Adaptive variability in the duration of critical windows of plasticity

PubMed Central

Wells, Jonathan C. K.

2014-01-01

Developmental plasticity underlies widespread associations between early-life exposures and many components of adult phenotype, including the risk of chronic diseases. Humans take almost two decades to reach reproductive maturity, and yet the ‘critical windows’ of physiological sensitivity that confer developmental plasticity tend to close during fetal life or infancy. While several explanations for lengthy human maturation have been offered, the brevity of physiological plasticity has received less attention. I argue that offspring plasticity is only viable within the niche of maternal care, and that as this protection is withdrawn, the offspring is obliged to canalize many developmental traits in order to minimize environmental disruptions. The schedule of maternal care may therefore shape the duration of critical windows, and since the duration of this care is subject to parent–offspring conflict, the resolution of this conflict may shape the duration of critical windows. This perspective may help understand (i) why windows close at different times for different traits, and (ii) why the duration of critical windows may vary across human populations. The issue is explored in relation to population differences in the association between infant weight gain and later body composition. The occupation of more stable environments by western populations may have favoured earlier closure of the critical window during which growth in lean mass is sensitive to nutritional intake. This may paradoxically have elevated the risk of obesity following rapid infant weight gain in such populations. PMID:25095791

Developmental plasticity of growth and digestive efficiency in dependence of early-life food availability

PubMed Central

Kotrschal, Alexander; Szidat, Sönke; Taborsky, Barbara

2014-01-01

Nutrition is a potent mediator of developmental plasticity. If food is scarce, developing organisms may invest into growth to outgrow size-dependent mortality (short-term benefit) and/or into an efficient digestion system (long-term benefit). We investigated this potential trade-off, by determining the influence of food availability on juvenile body and organ growth, and on adult digestive efficiency in the cichlid fish Simochromis pleurospilus. We reared two groups of fish at constant high or low food rations, and we switched four other groups between these two rations at an early and late juvenile period. We measured juvenile growth and organ sizes at different developmental stages and determined adult digestive efficiency. Fish kept at constant, high rations grew considerably faster than low-food fish. Nevertheless, S. pleurospilus partly buffered the negative effects of low food availability by developing heavier digestive organs, and they were therefore more efficient in digesting their food as adults. Results of fish exposed to a ration switch during either the early or late juvenile period suggest (i) that the ability to show compensatory growth after early exposure to low food availability persists during the juvenile period, (ii) that digestive efficiency is influenced by varying juvenile food availability during the late juvenile phase and (iii) that the efficiency of the adult digestive system is correlated with the growth rate during a narrow time window of juvenile period. PMID:25866430

Developmental Audits with Challenging Youth

ERIC Educational Resources Information Center

Brendtro, Larry K.; du Toit, Lesley; Bath, Howard; Van Bockern, Steve

2006-01-01

The Developmental Audit[R] is a new strength-based assessment model for youth who are in conflict in home, school, or community. Developmental Audits involve collaboration with young persons who are seen as experts on themselves. Discussing challenging life events provides a window to the young person's private logic and goals. The audit scans…

Timing of androgen receptor disruption and estrogen exposure underlies a spectrum of congenital penile anomalies

PubMed Central

Armfield, Brooke A.; Cohn, Martin J.

2015-01-01

Congenital penile anomalies (CPAs) are among the most common human birth defects. Reports of CPAs, which include hypospadias, chordee, micropenis, and ambiguous genitalia, have risen sharply in recent decades, but the causes of these malformations are rarely identified. Both genetic anomalies and environmental factors, such as antiandrogenic and estrogenic endocrine disrupting chemicals (EDCs), are suspected to cause CPAs; however, little is known about the temporal window(s) of sensitivity to EDCs, or the tissue-specific roles and downstream targets of the androgen receptor (AR) in external genitalia. Here, we show that the full spectrum of CPAs can be produced by disrupting AR at different developmental stages and in specific cell types in the mouse genital tubercle. Inactivation of AR during a narrow window of prenatal development results in hypospadias and chordee, whereas earlier disruptions cause ambiguous genitalia and later disruptions cause micropenis. The neonatal phase of penile development is controlled by the balance of AR to estrogen receptor α (ERα) activity; either inhibition of androgen or augmentation of estrogen signaling can induce micropenis. AR and ERα have opposite effects on cell division, apoptosis, and regulation of Hedgehog, fibroblast growth factor, bone morphogenetic protein, and Wnt signaling in the genital tubercle. We identify Indian hedgehog (Ihh) as a novel downstream target of AR in external genitalia and show that conditional deletion of Ihh inhibits penile masculinization. These studies reveal previously unidentified cellular and molecular mechanisms by which antiandrogenic and estrogenic signals induce penile malformations and demonstrate that the timing of endocrine disruption can determine the type of CPA. PMID:26598695

Interactions between Auxin Transport and the Actin Cytoskeleton in Developmental Polarity of Fucus distichus Embryos in Response to Light and Gravity1

PubMed Central

Sun, Haiguo; Basu, Swati; Brady, Shari R.; Luciano, Randy L.; Muday, Gloria K.

2004-01-01

Land plants orient their growth relative to light and gravity through complex mechanisms that require auxin redistribution. Embryos of brown algae use similar environmental stimuli to orient their developmental polarity. These studies of the brown algae Fucus distichus examined whether auxin and auxin transport are also required during polarization in early embryos and to orient growth in already developed tissues. These embryos polarize with the gravity vector in the absence of a light cue. The auxin, indole-3-acetic acid (IAA), and auxin efflux inhibitors, such as naphthylphthalamic acid (NPA), reduced environmental polarization in response to gravity and light vectors. Young rhizoids are negatively phototropic, and NPA also inhibits rhizoid phototropism. The effect of IAA and NPA on gravity and photopolarization is maximal within 2.5 to 4.5 h after fertilization (AF). Over the first 6 h AF, auxin transport is relatively constant, suggesting that developmentally controlled sensitivity to auxin determines the narrow window during which NPA and IAA reduce environmental polarization. Actin patches were formed during the first hour AF and began to photolocalize within 3 h, coinciding with the time of NPA and IAA action. Treatment with NPA reduced the polar localization of actin patches but not patch formation. Latrunculin B prevented environmental polarization in a time frame that overlaps the formation of actin patches and IAA and NPA action. Latrunculin B also altered auxin transport. Together, these results indicate a role for auxin in the orientation of developmental polarity and suggest interactions between the actin cytoskeleton and auxin transport in F. distichus embryos. PMID:15122028

9. INTERIOR LIVING ROOM DETAIL OF ONE OF TWO NARROW ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. INTERIOR LIVING ROOM DETAIL OF ONE OF TWO NARROW 4-LIGHT OVER 4-LIGHT, DOUBLE-HUNG, WOOD-FRAMED WINDOWS ON EITHER SIDE OF FRONT DOOR SHOWING EXPOSED COUNTERBALANCE CABLE. VIEW TO SOUTHWEST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

A Summary of the Evaluation of PPG Herculite XP Glass in Punched Window and Storefront Assemblies

DTIC Science & Technology

2013-01-01

frames for all IGU windows extruded from existing dies. The glazing was secured to the frame on all four sides with a 1/2-in bead width of DOW 995...lite and non-laminated IGU debris tests. A wood frame with a 4-in wide slit was placed behind the window to transform the debris cloud into a narrow...speed camera DIC Set-up laser deflection gauge shock tube window wood frame with slit high speed camerawell lit backdrop Debris Tracking Set-up laser

Evaluation of an Out-of-the-Window Air Traffic Control Tower Simulation for Controller Training

DOT National Transportation Integrated Search

1996-09-01

This study gathered evidence concerning the potential usefulness of out-of-the-window air traffic control tower : simulation for training tower controllers. Data were collected from all ten developmental controllers who completed : simulation trainin...

The Timing of the Excitatory-to-Inhibitory GABA Switch Is Regulated by the Oxytocin Receptor via KCC2

PubMed Central

Leonzino, Marianna; Busnelli, Marta; Antonucci, Flavia; Verderio, Claudia; Mazzanti, Michele; Chini, Bice

2016-01-01

Summary Oxytocin and its receptor (Oxtr) play a crucial role in the postnatal transition of neuronal GABA neurotransmission from excitatory to inhibitory, a developmental process known as the GABA switch. Using hippocampal neurons from Oxtr-null mice, we show that (1) Oxtr is necessary for the correct timing of the GABA switch by upregulating activity of the chloride cotransporter KCC2, (2) Oxtr, in a very early and narrow time window, directly modulates the functional activity of KCC2 by promoting its phosphorylation and insertion/stabilization at the neuronal surface, and (3) in the absence of Oxtr, electrophysiological alterations are recorded in mature neurons, a finding consistent with a reduced level of KCC2 and increased susceptibility to seizures observed in adult Oxtr-null mice. These data identify KCC2 as a key target of oxytocin in postnatal events that may be linked to pathogenesis of neurodevelopmental disorders. PMID:27052180

Alternative approach for management of an electrical storm in Brugada syndrome:Importance of primary ablation within a narrow time window.

PubMed

Talib, Ahmed Karim; Yui, Yoshiaki; Kaneshiro, Takashi; Sekiguchi, Yukio; Nogami, Akihiko; Aonuma, Kazutaka

2016-06-01

Placement of an implantable cardioverter-defibrillator (ICD) is the only powerful treatment modality for Brugada syndrome in patients presenting with ventricular fibrillation (VF). For those whose first presentation is an electrical storm, pharmacologic therapy is typically used to control VF followed by ICD implantation. We report an alternative approach whereby, before ICD implantation, emergency catheter ablation of the VF-triggering premature ventricular contraction (PVC) resulted in long-term VF-free survival. The results suggest that, because VF triggers appear in a narrow time window, ablation of the culprit PVCs that initiate VF before the index PVCs subside is a reasonable alternative approach.

The Audiovisual Temporal Binding Window Narrows in Early Childhood

ERIC Educational Resources Information Center

Lewkowicz, David J.; Flom, Ross

2014-01-01

Binding is key in multisensory perception. This study investigated the audio-visual (A-V) temporal binding window in 4-, 5-, and 6-year-old children (total N = 120). Children watched a person uttering a syllable whose auditory and visual components were either temporally synchronized or desynchronized by 366, 500, or 666 ms. They were asked…

7. INTERIOR OF LIVING ROOM SHOWING DISTINCTIVE 6LIGHT THREEPANEL DOOR, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. INTERIOR OF LIVING ROOM SHOWING DISTINCTIVE 6-LIGHT THREE-PANEL DOOR, ONE OF THE NARROW 4-LIGHT OVER 4-LIGHT, DOUBLE-HUNG WINDOWS FRAMING THE FRONT DOOR, AND THE PAIRED 6-LIGHT OVER 1-LIGHT, DOUBLE-HUNG WINDOWS. VIEW TO NORTHWEST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

Nondestrucive analysis of fuel pins

DOEpatents

Stepan, I.E.; Allard, N.P.; Suter, C.R.

1972-11-03

Disclosure is made of a method and a correspondingly adapted facility for the nondestructive analysis of the concentation of fuel and poison in a nuclear reactor fuel pin. The concentrations of fuel and poison in successive sections along the entire length of the fuel pin are determined by measuring the reactivity of a thermal reactor as each successive small section of the fuel pin is exposed to the neutron flux of the reactor core and comparing the measured reactivity with the reactivities measured for standard fuel pins having various known concentrations. Only a small section of the length of the fuel pin is exposed to the neutron flux at any one time while the remainder of the fuel pin is shielded from the neutron flux. In order to expose only a small section at any one time, a boron-10-lined dry traverse tube is passed through the test region within the core of a low-power thermal nuclear reactor which has a very high fuel sensitivity. A narrow window in the boron-10 lining is positioned at the core center line. The fuel pins are then systematically traversed through the tube past the narrow window such that successive small sections along the length of the fuel pin are exposed to the neutron flux which passes through the narrow window.

Letter-sound processing deficits in children with developmental dyslexia: An ERP study.

PubMed

Moll, Kristina; Hasko, Sandra; Groth, Katharina; Bartling, Jürgen; Schulte-Körne, Gerd

2016-04-01

The time course during letter-sound processing was investigated in children with developmental dyslexia (DD) and typically developing (TD) children using electroencephalography. Thirty-eight children with DD and 25 TD children participated in a visual-auditory oddball paradigm. Event-related potentials (ERPs) elicited by standard and deviant stimuli in an early (100-190 ms) and late (560-750 ms) time window were analysed. In the early time window, ERPs elicited by the deviant stimulus were delayed and less left lateralized over fronto-temporal electrodes for children with DD compared to TD children. In the late time window, children with DD showed higher amplitudes extending more over right frontal electrodes. Longer latencies in the early time window and stronger right hemispheric activation in the late time window were associated with slower reading and naming speed. Additionally, stronger right hemispheric activation in the late time window correlated with poorer phonological awareness skills. Deficits in early stages of letter-sound processing influence later more explicit cognitive processes during letter-sound processing. Identifying the neurophysiological correlates of letter-sound processing and their relation to reading related skills provides insight into the degree of automaticity during letter-sound processing beyond behavioural measures of letter-sound-knowledge. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Application of MEMS-based x-ray optics as tuneable nanosecond choppers

NASA Astrophysics Data System (ADS)

Chen, Pice; Walko, Donald A.; Jung, Il Woong; Li, Zhilong; Gao, Ya; Shenoy, Gopal K.; Lopez, Daniel; Wang, Jin

2017-08-01

Time-resolved synchrotron x-ray measurements often rely on using a mechanical chopper to isolate a set of x-ray pulses. We have started the development of micro electromechanical systems (MEMS)-based x-ray optics, as an alternate method to manipulate x-ray beams. In the application of x-ray pulse isolation, we recently achieved a pulse-picking time window of half a nanosecond, which is more than 100 times faster than mechanical choppers can achieve. The MEMS device consists of a comb-drive silicon micromirror, designed for efficiently diffracting an x-ray beam during oscillation. The MEMS devices were operated in Bragg geometry and their oscillation was synchronized to x-ray pulses, with a frequency matching subharmonics of the cycling frequency of x-ray pulses. The microscale structure of the silicon mirror in terms of the curvature and the quality of crystallinity ensures a narrow angular spread of the Bragg reflection. With the discussion of factors determining the diffractive time window, this report showed our approaches to narrow down the time window to half a nanosecond. The short diffractive time window will allow us to select single x-ray pulse out of a train of pulses from synchrotron radiation facilities.

Broadband Absorbing Exciton-Plasmon Metafluids with Narrow Transparency Windows.

PubMed

Yang, Jihua; Kramer, Nicolaas J; Schramke, Katelyn S; Wheeler, Lance M; Besteiro, Lucas V; Hogan, Christopher J; Govorov, Alexander O; Kortshagen, Uwe R

2016-02-10

Optical metafluids that consist of colloidal solutions of plasmonic and/or excitonic nanomaterials may play important roles as functional working fluids or as means for producing solid metamaterial coatings. The concept of a metafluid employed here is based on the picture that a single ballistic photon, propagating through the metafluid, interacts with a large collection of specifically designed optically active nanocrystals. We demonstrate water-based metafluids that act as broadband electromagnetic absorbers in a spectral range of 200-3300 nm and feature a tunable narrow (∼100 nm) transparency window in the visible-to-near-infrared region. To define this transparency window, we employ plasmonic gold nanorods. We utilize excitonic boron-doped silicon nanocrystals as opaque optical absorbers ("optical wall") in the UV and blue-green range of the spectrum. Water itself acts as an opaque "wall" in the near-infrared to infrared. We explore the limits of the concept of a "simple" metafluid by computationally testing and validating the effective medium approach based on the Beer-Lambert law. According to our simulations and experiments, particle aggregation and the associated decay of the window effect are one example of the failure of the simple metafluid concept due to strong interparticle interactions.

Evaluation of the Exceedance Rate of a Stationary Stochastic Process by Statistical Extrapolation Using the Envelope Peaks over Threshold (EPOT) Method

DTIC Science & Technology

2011-04-01

this limitation the length of the windows needs to be shortened. It is also leads to a narrower confidence interval, see Figure 2.9. 82 The " big ...least one event will occur within the window. The windows are then grouped in sets of two and the process is reapeated for a window size twice as big ...0 505 T. Fu 1 506 D. Walden 1 508 J. Brown 1 55 T.Applebee 0 55 M. Dipper 1 551 T. Smith I 551 C. Bassler 3 3 551 V. Belenky 1 551 W. Belknap

Interview with Violet Oaklander, Author of "Windows to Our Children."

ERIC Educational Resources Information Center

Campbell, Chari A.

1993-01-01

Presents interview with Dr. Violent Oaklander, experienced child therapist and author of "Windows to Our Children: A Gestalt Therapy with Children and Adolescents." Discusses critical components of successful therapy with children. Explains how developmental stage of child affects therapeutic process, and provides specific examples of working with…

REPRODUCTIVE AND DEVELOPMENTAL EFFECTS OF CONTAMINANTS IN OVIPAROUS VERTEBRATES: WORKSHOP SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS

EPA Science Inventory

Oviparous vertebrates generally occupy important niches in aquatic as well as terrestrial systems, and reproductive and developmental effects on these species can be of relatively great ecological significance. Because these organisms have critical windows of development, they ma...

Strategies for Reversing the Effects of Metabolic Disorders Induced as a Consequence of Developmental Programming

PubMed Central

Vickers, M. H.; Sloboda, D. M.

2012-01-01

Obesity and the metabolic syndrome have reached epidemic proportions worldwide with far-reaching health care and economic implications. The rapid increase in the prevalence of these disorders suggests that environmental and behavioral influences, rather than genetic causes, are fueling the epidemic. The developmental origins of health and disease hypothesis has highlighted the link between the periconceptual, fetal, and early infant phases of life and the subsequent development of metabolic disorders in later life. In particular, the impact of poor maternal nutrition on susceptibility to later life metabolic disease in offspring is now well documented. Several studies have now shown, at least in experimental animal models, that some components of the metabolic syndrome, induced as a consequence of developmental programming, are potentially reversible by nutritional or targeted therapeutic interventions during windows of developmental plasticity. This review will focus on critical windows of development and possible therapeutic avenues that may reduce metabolic and obesogenic risk following an adverse early life environment. PMID:22783205

Determination of design and operation parameters for upper atmospheric research instrumentation to yield optimum resolution with deconvolution, appendix 4

NASA Technical Reports Server (NTRS)

Ioup, George E.; Ioup, Juliette W.

1989-01-01

The power spectrum for a stationary random process can be defined with the Wiener-Khintchine Theorem, which says that the power spectrum and the auto correlation function are a Fourier transform pair. To implement this theorem for signals that are discrete and of finite length we can use the Blackman-Tukey method. Blackman and Tukey (1958) show that a function w(tau), called a lag window, can be applied to the auto correlation estimates to obtain power spectrum estimates that are statistically stable. The Fourier transform of w(r) is called a spectral window. Typical choices for spectral windows show a distinct trade-off between the main lobe width and side lobe strength. A new idea for designing windows by taking linear combinations of the standard windows to produce hybrid windows was introduced by Smith (1985). We implement Smith's idea to obtain spectral windows with narrow main lobes and smaller (compared with typical windows) near side lobes. One of the main contributions of this thesis is that we show that Smith's problem is equivalent to a Quadratic Programming (QP) problem with linear equality and inequality constraints. A computer program was written to produce hybrid windows by setting up and solving the QP problem. We also developed and solved two variations of the original problem. The two variations involved changing the inequality constraints in both cases from non negativity on the combination coefficients to non negativity on the hybrid lag window itself. For the second variation, the window functions used to construct the hybrid window were changed to a frequency-variable set of truncated cosinusoids. A series of tests was run with the three computer programs to investigate the behavior of the hybrid spectral and lag windows. Emphasis was put on obtaining spectral windows with both relatively narrow main lobes and the lowest possible (for these algorithms) near side lobes. Some success was achieved for this goal. A 10 dB peak side lobe reduction over the rectangular spectral window without significant main lobe broadening was achieved. Also, average side lobe levels of -117 dB were reached at a cost of doubling the main lobe width (at the -3 dB point).

Exposure to suboptimal temperatures during metamorphosis reveals a critical developmental window in the solitary bee, Megachile rotundata

USDA-ARS?s Scientific Manuscript database

Metamorphosis is an important developmental stage for holometabolous insects, during which adult morphology and physiology are established. Proper development relies on optimal body temperatures, and natural ambient temperature (Ta) fluctuations, especially in spring or in northern latitudes, could ...

Developmental spinal canal stenosis and somatotype.

PubMed Central

Nightingale, S

1989-01-01

The hypothesis that somatotype and cervical spine developmental canal stenosis may be associated has been investigated by anthropometry and measurement of lateral projection cervical spine radiographs. A significant association of canal size with somatotype has been found such that those with developmentally narrow canals are more likely to have relatively shorter long-bones, particularly in the upper arm, and longer trunks. Images PMID:2769282

Active two-phase cooling of an IR window for a hypersonic interceptor

NASA Astrophysics Data System (ADS)

Burzlaff, B. H.; Chivian, Jay S.; Cotten, W. D.; Hemphill, R. B.; Huhlein, Michael A.

1993-06-01

A novel actively cooled window for an IR sensor on a hypersonic interceptor is envisioned which achieves an IR window with high transmittance, low emittance, and low image distortion under high aerodynamic heat flux. The cooling concept employs two-phase convective boiling of liquid ammonia. Coolant is confined to narrow, parallel channels within the window to minimize obscuration of the aperture. The high latent heat of vaporization of ammonia minimizes coolant mass-flow requirements. Low boiling temperatures at projected operating pressures promote high thermal conductivity and low emissivity in the window. The concept was tested with thermal measurements on sub-mm width coolant channels in Si. High values for heat transfer coefficient and critical heat flux were obtained. Thermal gradients within the window can be controlled by the coolant channel configuration. Design options are investigated by predicting the effect of aerodynamic heat flux on the image produced by an IR sensor with a cooled window. Ammonia-cooled IR windows will function in the anticipated aerothermal environment.

Calculation of Retention Time Tolerance Windows with Absolute Confidence from Shared Liquid Chromatographic Retention Data

PubMed Central

Boswell, Paul G.; Abate-Pella, Daniel; Hewitt, Joshua T.

2015-01-01

Compound identification by liquid chromatography-mass spectrometry (LC-MS) is a tedious process, mainly because authentic standards must be run on a user’s system to be able to confidently reject a potential identity from its retention time and mass spectral properties. Instead, it would be preferable to use shared retention time/index data to narrow down the identity, but shared data cannot be used to reject candidates with an absolute level of confidence because the data are strongly affected by differences between HPLC systems and experimental conditions. However, a technique called “retention projection” was recently shown to account for many of the differences. In this manuscript, we discuss an approach to calculate appropriate retention time tolerance windows for projected retention times, potentially making it possible to exclude candidates with an absolute level of confidence, without needing to have authentic standards of each candidate on hand. In a range of multi-segment gradients and flow rates run among seven different labs, the new approach calculated tolerance windows that were significantly more appropriate for each retention projection than global tolerance windows calculated for retention projections or linear retention indices. Though there were still some small differences between the labs that evidently were not taken into account, the calculated tolerance windows only needed to be relaxed by 50% to make them appropriate for all labs. Even then, 42% of the tolerance windows calculated in this study without standards were narrower than those required by WADA for positive identification, where standards must be run contemporaneously. PMID:26292624

Calculation of retention time tolerance windows with absolute confidence from shared liquid chromatographic retention data.

PubMed

Boswell, Paul G; Abate-Pella, Daniel; Hewitt, Joshua T

2015-09-18

Compound identification by liquid chromatography-mass spectrometry (LC-MS) is a tedious process, mainly because authentic standards must be run on a user's system to be able to confidently reject a potential identity from its retention time and mass spectral properties. Instead, it would be preferable to use shared retention time/index data to narrow down the identity, but shared data cannot be used to reject candidates with an absolute level of confidence because the data are strongly affected by differences between HPLC systems and experimental conditions. However, a technique called "retention projection" was recently shown to account for many of the differences. In this manuscript, we discuss an approach to calculate appropriate retention time tolerance windows for projected retention times, potentially making it possible to exclude candidates with an absolute level of confidence, without needing to have authentic standards of each candidate on hand. In a range of multi-segment gradients and flow rates run among seven different labs, the new approach calculated tolerance windows that were significantly more appropriate for each retention projection than global tolerance windows calculated for retention projections or linear retention indices. Though there were still some small differences between the labs that evidently were not taken into account, the calculated tolerance windows only needed to be relaxed by 50% to make them appropriate for all labs. Even then, 42% of the tolerance windows calculated in this study without standards were narrower than those required by WADA for positive identification, where standards must be run contemporaneously. Copyright © 2015 Elsevier B.V. All rights reserved.

Constructivist developmental theory is needed in developmental neuroscience

NASA Astrophysics Data System (ADS)

Arsalidou, Marie; Pascual-Leone, Juan

2016-12-01

Neuroscience techniques provide an open window previously unavailable to the origin of thoughts and actions in children. Developmental cognitive neuroscience is booming, and knowledge from human brain mapping is finding its way into education and pediatric practice. Promises of application in developmental cognitive neuroscience rests however on better theory-guided data interpretation. Massive amounts of neuroimaging data from children are being processed, yet published studies often do not frame their work within developmental models—in detriment, we believe, to progress in this field. Here we describe some core challenges in interpreting the data from developmental cognitive neuroscience, and advocate the use of constructivist developmental theories of human cognition with a neuroscience interpretation.

A randomized trial to determine the impact on compliance of a psychophysical peripheral cue based on the Elaboration Likelihood Model.

PubMed

Horton, Rachael Jane; Minniti, Antoinette; Mireylees, Stewart; McEntegart, Damian

2008-11-01

Non-compliance in clinical studies is a significant issue, but causes remain unclear. Utilizing the Elaboration Likelihood Model of persuasion, this study assessed the psychophysical peripheral cue 'Interactive Voice Response System (IVRS) call frequency' on compliance. 71 participants were randomized to once daily (OD), twice daily (BID) or three times daily (TID) call schedules over two weeks. Participants completed 30-item cognitive function tests at each call. Compliance was defined as proportion of expected calls within a narrow window (+/- 30 min around scheduled time), and within a relaxed window (-30 min to +4 h). Data were analyzed by ANOVA and pairwise comparisons adjusted by the Bonferroni correction. There was a relationship between call frequency and compliance. Bonferroni adjusted pairwise comparisons showed significantly higher compliance (p=0.03) for the BID (51.0%) than TID (30.3%) for the narrow window; for the extended window, compliance was higher (p=0.04) with OD (59.5%), than TID (38.4%). The IVRS psychophysical peripheral cue call frequency supported the ELM as a route to persuasion. The results also support OD strategy for optimal compliance. Models suggest specific indicators to enhance compliance with medication dosing and electronic patient diaries to improve health outcomes and data integrity respectively.

Seismic facies analysis based on self-organizing map and empirical mode decomposition

NASA Astrophysics Data System (ADS)

Du, Hao-kun; Cao, Jun-xing; Xue, Ya-juan; Wang, Xing-jian

2015-01-01

Seismic facies analysis plays an important role in seismic interpretation and reservoir model building by offering an effective way to identify the changes in geofacies inter wells. The selections of input seismic attributes and their time window have an obvious effect on the validity of classification and require iterative experimentation and prior knowledge. In general, it is sensitive to noise when waveform serves as the input data to cluster analysis, especially with a narrow window. To conquer this limitation, the Empirical Mode Decomposition (EMD) method is introduced into waveform classification based on SOM. We first de-noise the seismic data using EMD and then cluster the data using 1D grid SOM. The main advantages of this method are resolution enhancement and noise reduction. 3D seismic data from the western Sichuan basin, China, are collected for validation. The application results show that seismic facies analysis can be improved and better help the interpretation. The powerful tolerance for noise makes the proposed method to be a better seismic facies analysis tool than classical 1D grid SOM method, especially for waveform cluster with a narrow window.

Ocean acidification has little effect on developmental thermal windows of echinoderms from Antarctica to the tropics.

PubMed

Karelitz, Sam E; Uthicke, Sven; Foo, Shawna A; Barker, Mike F; Byrne, Maria; Pecorino, Danilo; Lamare, Miles D

2017-02-01

As the ocean warms, thermal tolerance of developmental stages may be a key driver of changes in the geographical distributions and abundance of marine invertebrates. Additional stressors such as ocean acidification may influence developmental thermal windows and are therefore important considerations for predicting distributions of species under climate change scenarios. The effects of reduced seawater pH on the thermal windows of fertilization, embryology and larval morphology were examined using five echinoderm species: two polar (Sterechinus neumayeri and Odontaster validus), two temperate (Fellaster zelandiae and Patiriella regularis) and one tropical (Arachnoides placenta). Responses were examined across 12-13 temperatures ranging from -1.1 °C to 5.7 °C (S. neumayeri), -0.5 °C to 10.7 °C (O. validus), 5.8 °C to 27 °C (F. zelandiae), 6.0 °C to 27.1 °C (P. regularis) and 13.9 °C to 34.8 °C (A. placenta) under present-day and near-future (2100+) ocean acidification conditions (-0.3 pH units) and for three important early developmental stages 1) fertilization, 2) embryo (prehatching) and 3) larval development. Thermal windows for fertilization were broad and were not influenced by a pH decrease. Embryological development was less thermotolerant. For O. validus, P. regularis and A. placenta, low pH reduced normal development, albeit with no effect on thermal windows. Larval development in all five species was affected by both temperature and pH; however, thermal tolerance was not reduced by pH. Results of this study suggest that in terms of fertilization and development, temperature will remain as the most important factor influencing species' latitudinal distributions as the ocean continues to warm and decrease in pH, and that there is little evidence of a synergistic effect of temperature and ocean acidification on the thermal control of species ranges. © 2016 John Wiley & Sons Ltd.

Difference of auditory brainstem responses by stimulating to round and oval window in animal experiments.

PubMed

Lee, Jyung Hyun; Park, Hyo Soon; Wei, Qun; Kim, Myoung Nam; Cho, Jin-Ho

2017-01-02

ABSTACT To ensure the safety and efficacy of implantable hearing aids, animal experiments are an essential developmental procedure, in particular, auditory brainstem responses (ABRs) can be used to verify the objective effectiveness of implantable hearing aids. This study measured and compared the ABRs generated when applying the same vibration stimuli to an oval window and round window. The ABRs were measured using a TDT system 3 (TDT, USA), while the vibration stimuli were applied to a round window and oval window in 4 guinea pigs using a piezo-electric transducer with a proper contact tip. A paired t-test was used to determine any differences between the ABR amplitudes when applying the stimulation to an oval window and round window. The paired t-test revealed a significant difference between the ABR amplitudes generated by the round and oval window stimulation (t = 10.079, α < .0001). Therefore, the results confirmed that the biological response to round window stimulation was not the same as that to oval window stimulation.

Through Shared Windows: Outreach Project for Infants, Toddlers, and Children with Developmental Disabilities. Final Report.

ERIC Educational Resources Information Center

Harrison, Holly

This final report describes activities and accomplishments of the Through Shared Windows (TSW) Outreach Project, a 4-year project at the University of New Mexico designed to improve services to young children with disabilities and their families. Three major outcomes were accomplished. First, a Web site was developed that focuses on observational…

A protein-dye hybrid system as a narrow range tunable intracellular pH sensor.

PubMed

Anees, Palapuravan; Sudheesh, Karivachery V; Jayamurthy, Purushothaman; Chandrika, Arunkumar R; Omkumar, Ramakrishnapillai V; Ajayaghosh, Ayyappanpillai

2016-11-18

Accurate monitoring of pH variations inside cells is important for the early diagnosis of diseases such as cancer. Even though a variety of different pH sensors are available, construction of a custom-made sensor array for measuring minute variations in a narrow biological pH window, using easily available constituents, is a challenge. Here we report two-component hybrid sensors derived from a protein and organic dye nanoparticles whose sensitivity range can be tuned by choosing different ratios of the components, to monitor the minute pH variations in a given system. The dye interacts noncovalently with the protein at lower pH and covalently at higher pH, triggering two distinguishable fluorescent signals at 700 and 480 nm, respectively. The pH sensitivity region of the probe can be tuned for every unit of the pH window resulting in custom-made pH sensors. These narrow range tunable pH sensors have been used to monitor pH variations in HeLa cells using the fluorescence imaging technique.

Inhaled Antibiotics for Gram-Negative Respiratory Infections

PubMed Central

Fraidenburg, Dustin R.; Scardina, Tonya

2016-01-01

SUMMARY Gram-negative organisms comprise a large portion of the pathogens responsible for lower respiratory tract infections, especially those that are nosocomially acquired, and the rate of antibiotic resistance among these organisms continues to rise. Systemically administered antibiotics used to treat these infections often have poor penetration into the lung parenchyma and narrow therapeutic windows between efficacy and toxicity. The use of inhaled antibiotics allows for maximization of target site concentrations and optimization of pharmacokinetic/pharmacodynamic indices while minimizing systemic exposure and toxicity. This review is a comprehensive discussion of formulation and drug delivery aspects, in vitro and microbiological considerations, pharmacokinetics, and clinical outcomes with inhaled antibiotics as they apply to disease states other than cystic fibrosis. In reviewing the literature surrounding the use of inhaled antibiotics, we also highlight the complexities related to this route of administration and the shortcomings in the available evidence. The lack of novel anti-Gram-negative antibiotics in the developmental pipeline will encourage the innovative use of our existing agents, and the inhaled route is one that deserves to be further studied and adopted in the clinical arena. PMID:27226088

Primitive erythropoiesis is regulated by miR-126 via nonhematopoietic Vcam-1+ cells.

PubMed

Sturgeon, Christopher M; Chicha, Laurie; Ditadi, Andrea; Zhou, Qinbo; McGrath, Kathleen E; Palis, James; Hammond, Scott M; Wang, Shusheng; Olson, Eric N; Keller, Gordon

2012-07-17

Primitive erythropoiesis defines the onset of hematopoiesis in the yolk sac of the early embryo and is initiated by the emergence of progenitors assayed as colony-forming cells (EryP-CFCs). EryP-CFCs are detected for only a narrow window during embryonic development, suggesting that both their initiation and termination are tightly controlled. Using the embryonic stem differentiation system to model primitive erythropoiesis, we found that miR-126 regulates the termination of EryP-CFC development. Analyses of miR-126 null embryos revealed that this miR also regulates EryP-CFCs in vivo. We identified vascular cell adhesion molecule-1 (Vcam-1) expressed by a mesenchymal cell population as a relevant target of miR-126. Interaction of EryP-CFCs with Vcam-1 accelerated their maturation to ßh1-globin(+) and Ter119(+) cells through a Src family kinase. These findings uncover a cell nonautonomous regulatory pathway for primitive erythropoiesis that may provide insight into the mechanism(s) controlling the developmental switch from primitive to definitive hematopoiesis. Copyright © 2012 Elsevier Inc. All rights reserved.

The Traditional Approach to Developmental Education: Background and Effectiveness. Research Brief

ERIC Educational Resources Information Center

Horn, Aaron S.; Asmussen, John G.

2014-01-01

A significant challenge in higher education is to narrow the educational attainment gap between academically prepared and unprepared students. To this end, developmental or remedial education is intended to improve the academic skills and knowledge of students who are unprepared for undergraduate coursework, particularly in the areas of…

Diversity & Developmentally Appropriate Practices: Challenges for Early Childhood Education.

ERIC Educational Resources Information Center

Mallory, Bruce L., Ed.; New, Rebecca S., Ed.

The current conceptualization of what is appropriate in early childhood education is overly narrow in its interpretation of the role of the teacher, and with respect to variations in cultural and developmental diversity. Based on this observation, this book discusses various issues surrounding diversity, inclusion, and appropriate early…

How flexible is phenotypic plasticity? Developmental windows for trait induction and reversal.

PubMed

Hoverman, Jason T; Relyea, Rick A

2007-03-01

Inducible defenses allow prey to modulate their phenotypic responses to the level of predation risk in the environment and reduce the cost of constitutive defenses. Inherent in this statement is that prey must alter their phenotypes during development in order to form these defenses. This has lead many ecologists and evolutionary biologists to call for studies that examine developmental plasticity to provide insights into the importance of development in controlling the trajectories of trait formation, the integration of phenotypes over ontogeny, and the establishment of developmental windows for trait formation and reversal. By moving away from studies that focus on a single point in development, we can obtain a more complete understanding of the phenotypic decisions and limitations of prey. We exposed freshwater snails (Helisoma trivolvis) to environments in which predatory water bugs (Belostoma flumineum) were always absent, always present, or added and removed at different points in development. We discovered that snails formed morphological defenses against water bugs. Importantly, after the initial induction of defenses, snails showed similar developmental trajectories as snails reared without predators. Further, the snails possessed wide developmental windows for inducible defenses that extended past sexual maturity. However, being induced later in development appeared to have an associated cost (i.e., decreased shell thickness) that was not found when water bugs were always present. This epiphenotype (i.e., new shell formation as an extension of the current shell) suggests that resource limitation plays an important role in responses to temporal variation in predation risk and may have critical ecological costs that limit the benefits of the inducible defense. Lastly, the ability of snails to completely reverse their defenses was limited to early in ontogeny due to the constraints associated with modular growth of shell material. In sum, we demonstrate that taking a developmental perspective is extremely valuable for understanding the ecology of inducible defenses.

Round and Oval Window Anatomic Variability: Its Implication for the Vibroplasty Technique.

PubMed

Mancheño, Marta; Aristegui, Miguel; Sañudo, Jose Ramon

2017-06-01

The objective of this study is to evaluate the anatomical variability of round and oval window regions and its relationship with their closest structures, to determine its implication on the fitting and stabilization of the middle ear implant Vibrant Soundbridge. Variations of the anatomy of round and oval window regions were assessed in a total of 85 human dissected temporal bones. Afterward, we evaluated the adaptation and subsequent stabilization of the floating mass transducer (FMT) of the Vibrant Soundbridge in 67 cases in round window (RW) and in 22 cases in oval window (OW), and the influence that the variability of the different anatomical features examined had on this stabilization. We also assessed access and surgeon's view of the RW niche through the facial recess approach. Stabilization of the FMT in the RW was achieved in 53 (79%) of the 67 cases; we found that the less favorable anatomical conditions for stabilization were: membrane smaller than 1.5 mm, presence of a high jugular bulb and a narrow or very narrow RW niche. Frequently, two or more of these conditions happened simultaneously. In seven cases (22%) access to the RW through facial recess approach did not allow positioning the FMT in place. OW stabilization succeeded in 18 (82%) of the 22 cases. Round and oval window vibroplasty are difficult surgical techniques. To place the FMT directly on the OW may be easier as we do not have to drill the niche. In both regions there are some anatomical conditions that hinder fitting the FMT and even make it impossible. Once fitted, the main problem is to achieve good stabilization of the device.

Spectral Engineering of Slow Light, Cavity Line Narrowing, and Pulse Compression

NASA Astrophysics Data System (ADS)

Sabooni, Mahmood; Li, Qian; Rippe, Lars; Mohan, R. Krishna; Kröll, Stefan

2013-11-01

More than 4 orders of magnitude of cavity-linewidth narrowing in a rare-earth-ion-doped crystal cavity, emanating from strong intracavity dispersion caused by off-resonant interaction with dopant ions, is demonstrated. The dispersion profiles are engineered using optical pumping techniques creating significant semipermanent but reprogrammable changes of the rare-earth absorption profiles. Several cavity modes are shown within the spectral transmission window. Several possible applications of this phenomenon are discussed.

Protective broadband window coatings

NASA Astrophysics Data System (ADS)

Askinazi, Joel; Narayanan, Authi A.

1997-06-01

Optical windows employed in current and future airborne and ground based optical sensor systems are required to provide long service life under extreme environmental conditions including blowing sand and high speed rain. State of the art sensor systems are employing common aperture windows which must provide optical bandpasses from the TV to the LWIR. Operation Desert Storm experience indicates that current optical coatings provide limited environmental protection which adversely affects window life cycle cost. Most of these production coatings also have limited optical bandpasses (LWIR, MWIR, or TV-NIR). A family of optical coatings has been developed which provide a significant increase in rain and sand impact protection to current optical window materials. These coatings can also be tailored to provide either narrow optical bandwidth (e.g., LWIR) or broadband transmittance (TV- LWIR). They have been applied to a number of standard optical window materials. These coating have successfully completed airborne rain and sand abrasion test with minimal impact on optical window performance. Test results are presented. Low cost service life is anticipated as well as the ability to operate windows in even more taxing environments than currently feasible.

Gene x Environment Interactions in Reading Disability and Attention-Deficit/Hyperactivity Disorder

ERIC Educational Resources Information Center

Pennington, Bruce F.; McGrath, Lauren M.; Rosenberg, Jenni; Barnard, Holly; Smith, Shelley D.; Willcutt, Erik G.; Friend, Angela; DeFries, John C.; Olson, Richard K.

2009-01-01

This article examines Gene x Environment (G x E) interactions in two comorbid developmental disorders--reading disability (RD) and attention-deficit/hyperactivity disorder (ADHD)--as a window on broader issues on G x E interactions in developmental psychology. The authors first briefly review types of G x E interactions, methods for detecting…

Mindfulness and Compassion Training in Adolescence: A Developmental Contemplative Science Perspective

ERIC Educational Resources Information Center

Roeser, Robert W.; Pinela, Cristi

2014-01-01

Adolescence is a developmental period of risk, as well as a window of opportunity for cultivating positive development and thriving. It is characterized by simultaneous changes in the brain, body, mind, and social domains that offer a platform for building new skills and habits. This chapter discusses the role that secular forms of mindfulness and…

Influence of Conduct Problems and Depressive Symptomatology on Adolescent Substance Use: Developmentally Proximal versus Distal Effects

ERIC Educational Resources Information Center

Maslowsky, Julie; Schulenberg, John E.; Zucker, Robert A.

2014-01-01

The identification of developmentally specific windows at which key predictors of adolescent substance use are most influential is a crucial task for informing the design of appropriately targeted substance use prevention and intervention programs. The current study examined effects of conduct problems and depressive symptomatology on changes in…

Interior of the second floor dance hall showing tall and ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior of the second floor dance hall showing tall and narrow window openings with 10-foot scale near center, looking south. - Bower Building, 409-413 East Weber Avenue, Stockton, San Joaquin County, CA

Brain Responses Reveal That Infants' Face Discrimination Is Guided by Statistical Learning from Distributional Information

ERIC Educational Resources Information Center

Altvater-Mackensen, Nicole; Jessen, Sarah; Grossmann, Tobias

2017-01-01

Infants' perception of faces becomes attuned to the environment during the first year of life. However, the mechanisms that underpin perceptual narrowing for faces are only poorly understood. Considering the developmental similarities seen in perceptual narrowing for faces and speech and the role that statistical learning has been shown to play…

Challenges and opportunities in developmental integrative physiology☆

PubMed Central

Mueller, C.A.; Eme, J.; Burggren, W.W.; Roghair, R.D.; Rundle, S.D.

2015-01-01

This review explores challenges and opportunities in developmental physiology outlined by a symposium at the 2014 American Physiological Society Intersociety Meeting: Comparative Approaches to Grand Challenges in Physiology. Across animal taxa, adverse embryonic/fetal environmental conditions can alter morphological and physiological phenotypes in juveniles or adults, and capacities for developmental plasticity are common phenomena. Human neonates with body sizes at the extremes of perinatal growth are at an increased risk of adult disease, particularly hypertension and cardiovascular disease. There are many rewarding areas of current and future research in comparative developmental physiology. We present key mechanisms, models, and experimental designs that can be used across taxa to investigate patterns in, and implications of, the development of animal phenotypes. Intraspecific variation in the timing of developmental events can be increased through developmental plasticity (heterokairy), and could provide the raw material for selection to produce heterochrony — an evolutionary change in the timing of developmental events. Epigenetics and critical windows research recognizes that in ovo or fetal development represent a vulnerable period in the life history of an animal, when the developing organism may be unable to actively mitigate environmental perturbations. ‘Critical windows’ are periods of susceptibility or vulnerability to environmental or maternal challenges, periods when recovery from challenge is possible, and periods when the phenotype or epigenome has been altered. Developmental plasticity may allow survival in an altered environment, but it also has possible long-term consequences for the animal. “Catch-up growth” in humans after the critical perinatal window has closed elicits adult obesity and exacerbates a programmed hypertensive phenotype (one of many examples of “fetal programing”). Grand challenges for developmental physiology include integrating variation in developmental timing within and across generations, applying multiple stressor dosages and stressor exposure at different developmental timepoints, assessment of epigenetic and parental influences, developing new animal models and techniques, and assessing and implementing these designs and models in human health and development. PMID:25711780

Developmental origins of epigenetic transgenerational inheritance

PubMed Central

Hanson, Mark A.; Skinner, Michael K.

2016-01-01

Abstract Environmental factors can induce epigenetic alterations in the germ cells that can potentially be transmitted transgenerationally. This non-genetic form of inheritance is termed epigenetic transgenerational inheritance and has been shown in a variety of species including plants, flies, worms, fish, rodents, pigs, and humans. This phenomenon operates during specific critical windows of exposure, linked to the developmental biology of the germ cells (sperm and eggs). Therefore, concepts of the developmental origins of transgenerational inheritance of phenotypic variation and subsequent disease risk need to include epigenetic processes affecting the developmental biology of the germ cell. These developmental impacts on epigenetic transgenerational inheritance, in contrast to multigenerational exposures, are the focus of this Perspective. PMID:27390622

Self-Sustained Mode-3 Tear Controls Dynamics of Narrow Retreating Subduction Zones

NASA Astrophysics Data System (ADS)

Munch, J.; Gerya, T.; Ueda, K.

2017-12-01

The Caribbean oroclinal basin exhibits several narrow retreating slabs in an oceanic domain. The slabs show a curved shape associated to a bent topography (trench). We propose that the curvature of the topography depends on slab retreat mechanisms following mode-3 tearing at the edges of the slab (out of the plane fracture propagation). While first-order characteristics have been principally reproduced in self-sustained subduction initiation models (Gerya et al., 2015, Nature, 527, 221-225), the relevant observations have not been quantified and the exact mechanism is not understood. In this work, we study the long-term 3D evolution of narrowing oceanic subduction zones during retreat, and investigate the link between mode-3 tear and orocline formation. Numerical experiments are carried out with a thermo-mechanical 3D finite-difference code. To allow the observation of developing topography, the precise location of the internal surface and its evolution by material diffusion is tracked. Retreating subduction is facilitated via a strong age contrast between a young lithosphere window enclosed by shear zones and the surrounding lithosphere. By varying the length and thickness of the shear zones and location of the age transition, the influence of these parameters on the tearing process and the development of topography is assessed. Experiments trigger subduction initiation and slab retreat via fracture zone collapse and spontaneous paired mode-3 tear propagation within the oceanic plate interior. Narrow retreating subducting slabs form as a natural result of the spontaneous paired tearing process. A curved trench forms along with slab retreat. Topography evolution and tearing trajectory appear to be dependent on the initial shear zones and young window dimensions. We also note a strong narrowing of the slab during the retreat (several tens of kilometers over 800 km of retreat). Overall, results indicate that narrowing of retreating slabs is a self-consistent consequence of tear propagation dynamics. This plate tearing mechanism may control dynamics of other narrow retreating subduction zones worldwide.

Solar Eclipse

Atmospheric Science Data Center

2013-04-16

... View Larger Image Within that narrow window during a solar eclipse where an observer on Earth can watch the Moon's shadow obscure ... of the imagery acquired during Terra orbit 20920. The panels cover an area of about 380 kilometers x 2909 kilometers and use data ...

28. ROOM 211, VIEW TO THE SOUTHEAST. THE LONG NARROW ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

28. ROOM 211, VIEW TO THE SOUTHEAST. THE LONG NARROW SPACE HAS EXPOSED TRUSSWORK IN UNPAINTED WOOD AS DID ALL UPSTAIRS ROOMS IN THEIR ORIGINAL CONDITION. CLERESTORY WINDOWS ARE INTERSPERSED WITH VENTS ALONG BOTH LONG SIDES OF THE ROOM. WALLS HAVE WIDE WOOD PANELING THAT IS PAINTED, FLOORS ARE WOOD. DOORWAY IN SOUTHWEST WALL LEADS TO UNFINISHED ATTIC SPACE. - Presidio of San Francisco, Cavalry Stables, Cowles Street, between Lincoln Boulevard & McDowell Street, San Francisco, San Francisco County, CA

Beyond the dyad: making Developmental Origins of Health and Disease (DOHaD) interventions more inclusive.

PubMed

Pentecost, M; Ross, F C; Macnab, A

2018-02-01

Pregnant women, children under 2 and the first thousand days of life have been principal targets for Developmental Origins of Health and Disease interventions. This paradigm has been criticized for laying responsibility for health outcomes on pregnant women and mothers and through the thousand days focus inadvertently deflecting attention from other windows for intervention. Drawing on insights from the South African context, this commentary argues for integrated and inclusive interventions that encompass broader social framings. First, future interventions should include a wider range of actors. Second, broader action frameworks should encompass life-course approaches that identify multiple windows of opportunity for intervention. Using two examples - the inclusion of men, and engagement with adolescents - this commentary offers strategies for producing more inclusive interventions by using a broader social framework.

Developmental time windows for axon growth influence neuronal network topology.

PubMed

Lim, Sol; Kaiser, Marcus

2015-04-01

Early brain connectivity development consists of multiple stages: birth of neurons, their migration and the subsequent growth of axons and dendrites. Each stage occurs within a certain period of time depending on types of neurons and cortical layers. Forming synapses between neurons either by growing axons starting at similar times for all neurons (much-overlapped time windows) or at different time points (less-overlapped) may affect the topological and spatial properties of neuronal networks. Here, we explore the extreme cases of axon formation during early development, either starting at the same time for all neurons (parallel, i.e., maximally overlapped time windows) or occurring for each neuron separately one neuron after another (serial, i.e., no overlaps in time windows). For both cases, the number of potential and established synapses remained comparable. Topological and spatial properties, however, differed: Neurons that started axon growth early on in serial growth achieved higher out-degrees, higher local efficiency and longer axon lengths while neurons demonstrated more homogeneous connectivity patterns for parallel growth. Second, connection probability decreased more rapidly with distance between neurons for parallel growth than for serial growth. Third, bidirectional connections were more numerous for parallel growth. Finally, we tested our predictions with C. elegans data. Together, this indicates that time windows for axon growth influence the topological and spatial properties of neuronal networks opening up the possibility to a posteriori estimate developmental mechanisms based on network properties of a developed network.

Tuning the emission of aqueous Cu:ZnSe quantum dots to yellow light window

NASA Astrophysics Data System (ADS)

Wang, Chunlei; Hu, Zhiyang; Xu, Shuhong; Wang, Yanbin; Zhao, Zengxia; Wang, Zhuyuan; Cui, Yiping

2015-07-01

Synthesis of internally doped Cu:ZnSe QDs in an aqueous solution still suffers from narrow tunable emissions from the blue to green light window. In this work, we extended the emission window of aqueous Cu:ZnSe QDs to the yellow light window. Our results show that high solution pH, multiple injections of Zn precursors, and nucleation doping strategy are three key factors for preparing yellow emitted Cu:ZnSe QDs. All these factors can depress the reactivity of CuSe nuclei and Zn monomers, promoting ZnSe growth outside CuSe nuclei rather than form ZnSe nuclei separately. With increased ZnSe QD size, the conduction band and nearby trap state energy levels shift to higher energy sites, causing Cu:ZnSe QDs to have a much longer emission.

Design, Fabrication and Testing of Multilayer Coated X-Ray Optics for the Water Window Imaging X-Ray Microscope

NASA Technical Reports Server (NTRS)

Spencer, Dwight C.

1996-01-01

Hoover et. al. built and tested two imaging Schwarzschild multilayer microscopes. These instruments were constructed as prototypes for the "Water Window Imaging X-Ray Microscope," which is a doubly reflecting, multilayer x-ray microscope configured to operate within the "water window." The "water window" is the narrow region of the x-ray spectrum between the K absorption edges of oxygen (lamda = 23.3 Angstroms) and of carbon (lamda = 43.62 Angstroms), where water is relatively highly transmissive and carbon is highly absorptive. This property of these materials, thus permits the use of high resolution multilayer x-ray microscopes for producing high contrast images of carbon-based structures within the aqueous physiological environments of living cells. We report the design, fabrication and testing of multilayer optics that operate in this regime.

Toward a Narrower, More Pragmatic View of Developmental Dyspraxia

PubMed Central

Steinman, Kyle J.; Mostofsky, Stewart H.; Denckla, Martha B.

2010-01-01

Apraxia traditionally refers to impaired ability to carry out skilled movements in the absence of fundamental sensorimotor, language, or general cognitive impairment sufficient to preclude them. The child neurology literature includes a much broader and varied usage of the term developmental dyspraxia. It has been used to describe a wide range of motor symptoms, including clumsiness and general coordination difficulties, in various developmental disorders (including autistic spectrum disorders, developmental language disorders, and perinatal stroke). We argue for the need to restrict use of the term developmental dyspraxia to describe impaired performance of skilled gestures, recognizing that, unlike acquired adult-onset apraxia, coexisting sensory and motor problems may also be present. PMID:20032517

How Does the Narrowing of Eligibility Criteria Affect Enrollment in Part C Early Intervention?

ERIC Educational Resources Information Center

Elbaum, Batya; Celimli-Aksoy, Seniz; Marshall, Jennifer T.; Berkovits, Michelle D.

2017-01-01

In recent years, many states have narrowed their eligibility criteria for participation in the IDEA Part C early intervention (EI) program for infants and toddlers with or at risk for developmental delays. However, there is scant research on the effects of such a policy change on the population of children served or on the timing of children's…

Inhaled Antibiotics for Gram-Negative Respiratory Infections.

PubMed

Wenzler, Eric; Fraidenburg, Dustin R; Scardina, Tonya; Danziger, Larry H

2016-07-01

Gram-negative organisms comprise a large portion of the pathogens responsible for lower respiratory tract infections, especially those that are nosocomially acquired, and the rate of antibiotic resistance among these organisms continues to rise. Systemically administered antibiotics used to treat these infections often have poor penetration into the lung parenchyma and narrow therapeutic windows between efficacy and toxicity. The use of inhaled antibiotics allows for maximization of target site concentrations and optimization of pharmacokinetic/pharmacodynamic indices while minimizing systemic exposure and toxicity. This review is a comprehensive discussion of formulation and drug delivery aspects, in vitro and microbiological considerations, pharmacokinetics, and clinical outcomes with inhaled antibiotics as they apply to disease states other than cystic fibrosis. In reviewing the literature surrounding the use of inhaled antibiotics, we also highlight the complexities related to this route of administration and the shortcomings in the available evidence. The lack of novel anti-Gram-negative antibiotics in the developmental pipeline will encourage the innovative use of our existing agents, and the inhaled route is one that deserves to be further studied and adopted in the clinical arena. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Improved high-intensity microwave discharge lamp for atomic resonance absorption and fluorescence spectrometry.

PubMed

Lifshitz, A; Skinner, G B; Wood, D R

1978-09-01

An unusually good combination of high intensity and narrow line has been achieved in a microwave discharge lamp by placing the optical window in the center of the microwave cavity. Construction details and performance characteristics are described.

The monaural temporal window based on masking period pattern data in school-aged children and adults.

PubMed

Buss, Emily; He, Shuman; Grose, John H; Hall, Joseph W

2013-03-01

Several lines of evidence indicate that auditory temporal resolution improves over childhood, whereas other data implicate the development of processing efficiency. The present study used the masking period pattern paradigm to examine the maturation of temporal processing in normal-hearing children (4.8 to 10.7 yrs) compared to adults. Thresholds for a brief tone were measured at 6 temporal positions relative to the period of a 5-Hz quasi-square-wave masker envelope, with a 20-dB modulation depth, as well as in 2 steady maskers. The signal was a pure tone at either 1000 or 6500 Hz, and the masker was a band of noise, either spectrally wide or narrow (21.3 and 1.4 equivalent rectangular bandwidths, respectively). Masker modulation improved thresholds more for wide than narrow bandwidths, and adults tended to receive more benefit from modulation than young children. Fits to data for the wide maskers indicated a change in window symmetry with development, reflecting relatively greater backward masking for the youngest listeners. Data for children >6.5 yrs of age appeared more adult-like for the 6500- than the 1000-Hz signal. Differences in temporal window asymmetry with listener age cannot be entirely explained as a consequence of a higher criterion for detection in children, a form of inefficiency.

BE-PLUS: a new base editing tool with broadened editing window and enhanced fidelity.

PubMed

Jiang, Wen; Feng, Songjie; Huang, Shisheng; Yu, Wenxia; Li, Guanglei; Yang, Guang; Liu, Yajing; Zhang, Yu; Zhang, Lei; Hou, Yu; Chen, Jia; Chen, Jieping; Huang, Xingxu

2018-06-06

Base editor (BE), containing a cytidine deaminase and catalytically defective Cas9, has been widely used to perform base editing. However, the narrow editing window of BE limits its utility. Here, we developed a new editing technology named as base editor for programming larger C to U (T) scope (BE-PLUS) by fusing 10 copies of GCN4 peptide to nCas9(D10A) for recruiting scFv-APOBEC-UGI-GB1 to the target sites. The new system achieves base editing with a broadened window, resulting in an increased genome-targeting scope. Interestingly, the new system yielded much fewer unwanted indels and non-C-to-T conversions. We also demonstrated its potential use in gene disruption across the whole genome through induction of stop codons (iSTOP). Taken together, the BE-PLUS system offers a new editing tool with increased editing window and enhanced fidelity.

Electrochemical Synthesis of Bismuth Particles: Tuning Particle Shape through Substrate Type within a Narrow Potential Window

PubMed Central

Bilican, Doga; Fornell, Jordina; Sort, Jordi; Pellicer, Eva

2017-01-01

Bismuth (Bi) electrodeposition was studied on Si/Ti/Au, FTO-, and ITO-coated glasses from acidic nitrate solutions with and without gluconate within a narrow potential window (ΔE = 80 mV). This potential range was sufficient to observe a change in particle shape, from polyhedrons (including hexagons) to dendrites, the trend being slightly different depending on substrate activity. In all cases, though, the formation of dendrites was favoured as the applied potential was made more negative. Bi particles were more uniformly distributed over the substrate when sodium gluconate was added to the electrolyte. X-ray diffraction analyses of dendrites grown at −0.28 V indicated that they exhibit the rhombohedral phase of Bi and are predominantly oriented along the (003) plane. This orientation is exacerbated at the lowest applied potential (−0.20 V vs. Ag|AgCl) on glass/ITO substrate, for which completed and truncated hexagons are observed from the top view scanning electron microscopy images. PMID:28772402

Triple tailored nonlinear dispersion of dressed four- and six-wave mixing

NASA Astrophysics Data System (ADS)

Sun, Yanyong; Wang, Zhiguo; Zhang, Zhaoyang; Gu, Bingling; Wang, Kun; Yang, Gaoguo; Zhang, Yanpeng

2018-06-01

We investigate the spectral signals and spatial images of a probe transmission signal, four-wave mixing (FWM), and six-wave mixing (SWM) under double dressing effects in an inverted Y-type system. Especially, we get the triple tailored nonlinear dispersion (about 60 MHz) of the dressed FWM and SWM through the interaction between electromagnetically induced transparency (EIT) windows and the Kerr nonlinearity. Moreover, SWM and dressed FWM with narrow linewidth are obtained through the tailoring of the three EIT windows, which is much narrower than the EIT. In addition, we first elaborate the modulation effect from the self-Kerr coefficient of FWM on the spot. We also investigate the spatial characteristics (defocusing, shifting, and splitting) of FWM and SWM induced by tailored self-Kerr and cross-Kerr effects among the relative fields. Such spatial shifting, splitting induced by the tailored nonlinear dispersion can be used for a higher contrast and high speed switch as well as a high resolution router.

Effects of temporal variability in ground data collection on classification accuracy

USGS Publications Warehouse

Hoch, G.A.; Cully, J.F.

1999-01-01

This research tested whether the timing of ground data collection can significantly impact the accuracy of land cover classification. Ft. Riley Military Reservation, Kansas, USA was used to test this hypothesis. The U.S. Army's Land Condition Trend Analysis (LCTA) data annually collected at military bases was used to ground truth disturbance patterns. Ground data collected over an entire growing season and data collected one year after the imagery had a kappa statistic of 0.33. When using ground data from only within two weeks of image acquisition the kappa statistic improved to 0.55. Potential sources of this discrepancy are identified. These data demonstrate that there can be significant amounts of land cover change within a narrow time window on military reservations. To accurately conduct land cover classification at military reservations, ground data need to be collected in as narrow a window of time as possible and be closely synchronized with the date of the satellite imagery.

Alterations in audiovisual simultaneity perception in amblyopia

PubMed Central

2017-01-01

Amblyopia is a developmental visual impairment that is increasingly recognized to affect higher-level perceptual and multisensory processes. To further investigate the audiovisual (AV) perceptual impairments associated with this condition, we characterized the temporal interval in which asynchronous auditory and visual stimuli are perceived as simultaneous 50% of the time (i.e., the AV simultaneity window). Adults with unilateral amblyopia (n = 17) and visually normal controls (n = 17) judged the simultaneity of a flash and a click presented with both eyes viewing. The signal onset asynchrony (SOA) varied from 0 ms to 450 ms for auditory-lead and visual-lead conditions. A subset of participants with amblyopia (n = 6) was tested monocularly. Compared to the control group, the auditory-lead side of the AV simultaneity window was widened by 48 ms (36%; p = 0.002), whereas that of the visual-lead side was widened by 86 ms (37%; p = 0.02). The overall mean window width was 500 ms, compared to 366 ms among controls (37% wider; p = 0.002). Among participants with amblyopia, the simultaneity window parameters were unchanged by viewing condition, but subgroup analysis revealed differential effects on the parameters by amblyopia severity, etiology, and foveal suppression status. Possible mechanisms to explain these findings include visual temporal uncertainty, interocular perceptual latency asymmetry, and disruption of normal developmental tuning of sensitivity to audiovisual asynchrony. PMID:28598996

Alterations in audiovisual simultaneity perception in amblyopia.

PubMed

Richards, Michael D; Goltz, Herbert C; Wong, Agnes M F

2017-01-01

Amblyopia is a developmental visual impairment that is increasingly recognized to affect higher-level perceptual and multisensory processes. To further investigate the audiovisual (AV) perceptual impairments associated with this condition, we characterized the temporal interval in which asynchronous auditory and visual stimuli are perceived as simultaneous 50% of the time (i.e., the AV simultaneity window). Adults with unilateral amblyopia (n = 17) and visually normal controls (n = 17) judged the simultaneity of a flash and a click presented with both eyes viewing. The signal onset asynchrony (SOA) varied from 0 ms to 450 ms for auditory-lead and visual-lead conditions. A subset of participants with amblyopia (n = 6) was tested monocularly. Compared to the control group, the auditory-lead side of the AV simultaneity window was widened by 48 ms (36%; p = 0.002), whereas that of the visual-lead side was widened by 86 ms (37%; p = 0.02). The overall mean window width was 500 ms, compared to 366 ms among controls (37% wider; p = 0.002). Among participants with amblyopia, the simultaneity window parameters were unchanged by viewing condition, but subgroup analysis revealed differential effects on the parameters by amblyopia severity, etiology, and foveal suppression status. Possible mechanisms to explain these findings include visual temporal uncertainty, interocular perceptual latency asymmetry, and disruption of normal developmental tuning of sensitivity to audiovisual asynchrony.

On the relationship between instantaneous phase synchrony and correlation-based sliding windows for time-resolved fMRI connectivity analysis.

PubMed

Pedersen, Mangor; Omidvarnia, Amir; Zalesky, Andrew; Jackson, Graeme D

2018-06-08

Correlation-based sliding window analysis (CSWA) is the most commonly used method to estimate time-resolved functional MRI (fMRI) connectivity. However, instantaneous phase synchrony analysis (IPSA) is gaining popularity mainly because it offers single time-point resolution of time-resolved fMRI connectivity. We aim to provide a systematic comparison between these two approaches, on both temporal and topological levels. For this purpose, we used resting-state fMRI data from two separate cohorts with different temporal resolutions (45 healthy subjects from Human Connectome Project fMRI data with repetition time of 0.72 s and 25 healthy subjects from a separate validation fMRI dataset with a repetition time of 3 s). For time-resolved functional connectivity analysis, we calculated tapered CSWA over a wide range of different window lengths that were temporally and topologically compared to IPSA. We found a strong association in connectivity dynamics between IPSA and CSWA when considering the absolute values of CSWA. The association between CSWA and IPSA was stronger for a window length of ∼20 s (shorter than filtered fMRI wavelength) than ∼100 s (longer than filtered fMRI wavelength), irrespective of the sampling rate of the underlying fMRI data. Narrow-band filtering of fMRI data (0.03-0.07 Hz) yielded a stronger relationship between IPSA and CSWA than wider-band (0.01-0.1 Hz). On a topological level, time-averaged IPSA and CSWA nodes were non-linearly correlated for both short (∼20 s) and long (∼100 s) windows, mainly because nodes with strong negative correlations (CSWA) displayed high phase synchrony (IPSA). IPSA and CSWA were anatomically similar in the default mode network, sensory cortex, insula and cerebellum. Our results suggest that IPSA and CSWA provide comparable characterizations of time-resolved fMRI connectivity for appropriately chosen window lengths. Although IPSA requires narrow-band fMRI filtering, we recommend the use of IPSA given that it does not mandate a (semi-)arbitrary choice of window length and window overlap. A code for calculating IPSA is provided. Copyright © 2018. Published by Elsevier Inc.

Genetics Home Reference: Lujan syndrome

MedlinePlus

... attention-seeking. Some affected individuals have features of autism or related developmental disorders affecting communication and social ... a narrow roof of the mouth (palate) ; crowded teeth ; and a small chin ( micrognathia ). Almost all people ...

IDENTIFYING CRITICAL WINDOWS OF EXPOSURE FOR CHILDREN'S HEALTH

EPA Science Inventory

Several authors have considered the importance of exposure timing and how this affects the outcomes observed, but no one has systematically compiled preconceptional, prentatal, and postnatal developmental exposures and subsequent outcomes. Efforts were undertaken to examine the ...

Profitability of integrated management of fusarium head blight in North Carolina winter wheat

USDA-ARS?s Scientific Manuscript database

Fusarium head blight (FHB) is one of the most difficult small-grain diseases to manage, due to the partial effectiveness of management techniques and the narrow window of time within which to apply fungicides profitably. The most effective management approach is to integrate cultivar resistance wit...

High fat programming of beta cell compensation, exhaustion, death and dysfunction.

PubMed

Cerf, Marlon E

2015-03-01

Programming refers to events during critical developmental windows that shape progeny health outcomes. Fetal programming refers to the effects of intrauterine (in utero) events. Lactational programming refers to the effects of events during suckling (weaning). Developmental programming refers to the effects of events during both fetal and lactational life. Postnatal programming refers to the effects of events either from birth (lactational life) to adolescence or from weaning (end of lactation) to adolescence. Islets are most plastic during the early life course; hence programming during fetal and lactational life is most potent. High fat (HF) programming is the maintenance on a HF diet (HFD) during critical developmental life stages that alters progeny metabolism and physiology. HF programming induces variable diabetogenic phenotypes dependent on the timing and duration of the dietary insult. Maternal obesity reinforces HF programming effects in progeny. HF programming, through acute hyperglycemia, initiates beta cell compensation. However, HF programming eventually leads to chronic hyperglycemia that triggers beta cell exhaustion, death and dysfunction. In HF programming, beta cell dysfunction often co-presents with insulin resistance. Balanced, healthy nutrition during developmental windows is critical for preserving beta cell structure and function. Thus early positive nutritional interventions that coincide with the development of beta cells may reduce the overwhelming burden of diabetes and metabolic disease. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dependence of Surface Contrast on Emission Angle in Cassini ISS 938-nm Images of Titan

NASA Technical Reports Server (NTRS)

Fussner, S.; McEwen, A.; Perry, J.; Turtle, E.; Dawson, D.; Porco, C.; West, R.

2005-01-01

Titan, the largest of Saturn s moons, is one of the most difficult solid surfaces in the Solar System to study. It is shrouded in a thick atmosphere with fine haze particles extending up to 500 km. [1] The atmosphere itself is rich in methane, which allows clear viewing of the surface only through narrow "windows" in the methane spectrum. Even in these methane windows, the haze absorbs and scatters light, blurring surface features and reducing the contrast of images. The haze optical depth is high at visible wavelengths, and decreases at longer (infrared) wavelengths. [2

Life History theory hypotheses on child growth: Potential implications for short and long-term child growth, development and health.

PubMed

Said-Mohamed, Rihlat; Pettifor, John M; Norris, Shane A

2018-01-01

Life history theory integrates ecological, physiological, and molecular layers within an evolutionary framework to understand organisms' strategies to optimize survival and reproduction. Two life history hypotheses and their implications for child growth, development, and health (illustrated in the South African context) are reviewed here. One hypothesis suggests that there is an energy trade-off between linear growth and brain growth. Undernutrition in infancy and childhood may trigger adaptive physiological mechanisms prioritizing the brain at the expense of body growth. Another hypothesis is that the period from conception to infancy is a critical window of developmental plasticity of linear growth, the duration of which may vary between and within populations. The transition from infancy to childhood may mark the end of a critical window of opportunity for improving child growth. Both hypotheses emphasize the developmental plasticity of linear growth and the potential determinants of growth variability (including the role of parent-offspring conflict in maternal resources allocation). Implications of these hypotheses in populations with high burdens of undernutrition and infections are discussed. In South Africa, HIV/AIDS during pregnancy (associated with adverse birth outcomes, short duration of breastfeeding, and social consequences) may lead to a shortened window of developmental plasticity of growth. Furthermore, undernutrition and infectious diseases in children living in South Africa, a country undergoing a rapid nutrition transition, may have adverse consequences on individuals' cognitive abilities and risks of cardio-metabolic diseases. Studies are needed to identify physiological mechanisms underlying energy allocation between biological functions and their potential impacts on health. © 2017 Wiley Periodicals, Inc.

Free-breathing 3D Cardiac MRI Using Iterative Image-Based Respiratory Motion Correction

PubMed Central

Moghari, Mehdi H.; Roujol, Sébastien; Chan, Raymond H.; Hong, Susie N.; Bello, Natalie; Henningsson, Markus; Ngo, Long H.; Goddu, Beth; Goepfert, Lois; Kissinger, Kraig V.; Manning, Warren J.; Nezafat, Reza

2012-01-01

Respiratory motion compensation using diaphragmatic navigator (NAV) gating with a 5 mm gating window is conventionally used for free-breathing cardiac MRI. Due to the narrow gating window, scan efficiency is low resulting in long scan times, especially for patients with irregular breathing patterns. In this work, a new retrospective motion compensation algorithm is presented to reduce the scan time for free-breathing cardiac MRI that increasing the gating window to 15 mm without compromising image quality. The proposed algorithm iteratively corrects for respiratory-induced cardiac motion by optimizing the sharpness of the heart. To evaluate this technique, two coronary MRI datasets with 1.3 mm3 resolution were acquired from 11 healthy subjects (7 females, 25±9 years); one using a NAV with a 5 mm gating window acquired in 12.0±2.0 minutes and one with a 15 mm gating window acquired in 7.1±1.0 minutes. The images acquired with a 15 mm gating window were corrected using the proposed algorithm and compared to the uncorrected images acquired with the 5 mm and 15 mm gating windows. The image quality score, sharpness, and length of the three major coronary arteries were equivalent between the corrected images and the images acquired with a 5 mm gating window (p-value>0.05), while the scan time was reduced by a factor of 1.7. PMID:23132549

Neuroendocrine models of social anxiety disorder

PubMed Central

van Honk, Jack; Bos, Peter A.; Terburg, David; Heany, Sarah; Stein, Dan J.

2015-01-01

Social anxiety disorder (SAD) is a highly prevalent and disabling disorder with key behavioral traits of social fearfulness, social avoidance, and submissiveness. Here we argue that hormonal systems play a key role in mediating social anxiety, and so may be important in SAD. Hormonal alterations, often established early in development through the interaction between biological and psychological factors (eg, genetic predisposition x early trauma), predispose to socially fearful, avoidant, and submissive behavior. However, whereas gene variants and histories of trauma persist, hormonal systems can be remodeled over the course of life. Hormones play a key role during the periods of all sensitive developmental windows (ie, prenatal, neonatal, puberty, aging), and are capable of opening up new developmental windows in adulthood. Indeed, the developmental plasticity of our social brain, and thus of social behavior in adulthood, critically depends on steroid hormones such as testosterone and peptide hormones such as oxytocin. These steroid and peptide hormones in interaction with social experiences may have potential for reprogramming the socially anxious brain. Certainly, single administrations of oxytocin and testosterone in humans reduce socially fearful, avoidant, and submissive behavior. Such work may ultimately lead to new approaches to the treatment of SAD. PMID:26487809

Signal and noise level estimation for narrow spectral width returns observed by the Indian MST radar

NASA Astrophysics Data System (ADS)

Hooper, D. A.

1999-07-01

Use is made of five sets of multibeam observations of the lower atmosphere made by the Indian mesosphere-stratosphere-troposphere (MST) radar. Two aspects of signal processing which can lead to serious underestimates of the signal-to-noise ratio are considered. First, a comparison is made of the effects of different data weighting windows applied to the inphase and quadrature components of the radar return samples prior to Fourier transformation. The relatively high degree of spectral leakage associated with the rectangular and Hamming windows can give rise to overestimates of the noise levels by up to 28 dB for the strongest signals. Use of the Hanning window is found to be the most appropriate for these particular data. Second, a technique for removing systematic dc biases from the data in the time domain is compared with the more well-known practice of correction in the frequency domain. The latter technique, which is often used to remove the effects of ground clutter, is shown to be particularly inappropriate for the characteristically narrow spectral width signals observed by the Indian MST radar. For cases of near-zero Doppler shift it can remove up to 30 dB of signal information. The consequences of noise and signal level discrepancies for studies of refractivity structures are discussed. It is shown that neither problem has a significant effect on Doppler shift or spectral width estimates.

Arabidopsis Plastidial Folylpolyglutamate Synthetase Is Required for Seed Reserve Accumulation and Seedling Establishment in Darkness

PubMed Central

Meng, Hongyan; Jiang, Ling; Xu, Bosi; Guo, Wenzhu; Li, Jinglai; Zhu, Xiuqing; Qi, Xiaoquan; Duan, Lixin; Meng, Xianbin; Fan, Yunliu; Zhang, Chunyi

2014-01-01

Interactions among metabolic pathways are important in plant biology. At present, not much is known about how folate metabolism affects other metabolic pathways in plants. Here we report a T-DNA insertion mutant (atdfb-3) of the plastidial folylpolyglutamate synthetase gene (AtDFB) was defective in seed reserves and skotomorphogenesis. Lower carbon (C) and higher nitrogen (N) content in the mutant seeds than that of the wild type were indicative of an altered C and N partitioning capacity. Higher levels of organic acids and sugars were detected in the mutant seeds compared with the wild type. Further analysis revealed that atdfb-3 seeds contained less total amino acids and individual Asn and Glu as well as NO3 −. These results indicate significant changes in seed storage in the mutant. Defects in hypocotyl elongation were observed in atdfb-3 in darkness under sufficient NO3 − conditions, and further enhanced under NO3 − limited conditions. The strong expression of AtDFB in cotyledons and hypocotyl during early developmental stage was consistent with the mutant sensitivity to limited NO3 − during a narrow developmental window. Exogenous 5-formyl-tetrahydrofolate completely restored the hypocotyl length in atdfb-3 seedlings with NO3 − as the sole N source. Further study demonstrated that folate profiling and N metabolism were perturbed in atdfb-3 etiolated seedlings. The activity of enzymes involved in N reduction and assimilation was altered in atdfb-3. Taken together, these results indicate that AtDFB is required for seed reserves, hypocotyl elongation and N metabolism in darkness, providing novel insights into potential associations of folate metabolism with seed reserve accumulation, N metabolism and hypocotyl development in Arabidopsis. PMID:25000295

Arabidopsis plastidial folylpolyglutamate synthetase is required for seed reserve accumulation and seedling establishment in darkness.

PubMed

Meng, Hongyan; Jiang, Ling; Xu, Bosi; Guo, Wenzhu; Li, Jinglai; Zhu, Xiuqing; Qi, Xiaoquan; Duan, Lixin; Meng, Xianbin; Fan, Yunliu; Zhang, Chunyi

2014-01-01

Interactions among metabolic pathways are important in plant biology. At present, not much is known about how folate metabolism affects other metabolic pathways in plants. Here we report a T-DNA insertion mutant (atdfb-3) of the plastidial folylpolyglutamate synthetase gene (AtDFB) was defective in seed reserves and skotomorphogenesis. Lower carbon (C) and higher nitrogen (N) content in the mutant seeds than that of the wild type were indicative of an altered C and N partitioning capacity. Higher levels of organic acids and sugars were detected in the mutant seeds compared with the wild type. Further analysis revealed that atdfb-3 seeds contained less total amino acids and individual Asn and Glu as well as NO3-. These results indicate significant changes in seed storage in the mutant. Defects in hypocotyl elongation were observed in atdfb-3 in darkness under sufficient NO3- conditions, and further enhanced under NO3- limited conditions. The strong expression of AtDFB in cotyledons and hypocotyl during early developmental stage was consistent with the mutant sensitivity to limited NO3- during a narrow developmental window. Exogenous 5-formyl-tetrahydrofolate completely restored the hypocotyl length in atdfb-3 seedlings with NO3- as the sole N source. Further study demonstrated that folate profiling and N metabolism were perturbed in atdfb-3 etiolated seedlings. The activity of enzymes involved in N reduction and assimilation was altered in atdfb-3. Taken together, these results indicate that AtDFB is required for seed reserves, hypocotyl elongation and N metabolism in darkness, providing novel insights into potential associations of folate metabolism with seed reserve accumulation, N metabolism and hypocotyl development in Arabidopsis.

Hydrocephalus and arthrogryposis in an immunocompetent mouse model of ZIKA teratogeny: A developmental study

PubMed Central

Xavier-Neto, Jose; Carvalho, Murilo; Pascoalino, Bruno dos Santos; Cardoso, Alisson Campos; Costa, Ângela Maria Sousa; Pereira, Ana Helena Macedo; Santos, Luana Nunes; Saito, Ângela; Marques, Rafael Elias; Smetana, Juliana Helena Costa; Consonni, Silvio Roberto; Bandeira, Carla; Costa, Vivian Vasconcelos; Bajgelman, Marcio Chaim; de Oliveira, Paulo Sérgio Lopes; Cordeiro, Marli Tenorio; Gonzales Gil, Laura Helena Vega; Pauletti, Bianca Alves; Granato, Daniela Campos; Paes Leme, Adriana Franco; Freitas-Junior, Lucio; Holanda de Freitas, Carolina Borsoi Moraes; Teixeira, Mauro Martins; Bevilacqua, Estela; Franchini, Kleber

2017-01-01

The teratogenic mechanisms triggered by ZIKV are still obscure due to the lack of a suitable animal model. Here we present a mouse model of developmental disruption induced by ZIKV hematogenic infection. The model utilizes immunocompetent animals from wild-type FVB/NJ and C57BL/6J strains, providing a better analogy to the human condition than approaches involving immunodeficient, genetically modified animals, or direct ZIKV injection into the brain. When injected via the jugular vein into the blood of pregnant females harboring conceptuses from early gastrulation to organogenesis stages, akin to the human second and fifth week of pregnancy, ZIKV infects maternal tissues, placentas and embryos/fetuses. Early exposure to ZIKV at developmental day 5 (second week in humans) produced complex manifestations of anterior and posterior dysraphia and hydrocephalus, as well as severe malformations and delayed development in 10.5 days post-coitum (dpc) embryos. Exposure to the virus at 7.5–9.5 dpc induces intra-amniotic hemorrhage, widespread edema, and vascular rarefaction, often prominent in the cephalic region. At these stages, most affected embryos/fetuses displayed gross malformations and/or intrauterine growth restriction (IUGR), rather than isolated microcephaly. Disrupted conceptuses failed to achieve normal developmental landmarks and died in utero. Importantly, this is the only model so far to display dysraphia and hydrocephalus, the harbinger of microcephaly in humans, as well as arthrogryposis, a set of abnormal joint postures observed in the human setting. Late exposure to ZIKV at 12.5 dpc failed to produce noticeable malformations. We have thus characterized a developmental window of opportunity for ZIKV-induced teratogenesis encompassing early gastrulation, neurulation and early organogenesis stages. This should not, however, be interpreted as evidence for any safe developmental windows for ZIKV exposure. Late developmental abnormalities correlated with damage to the placenta, particularly to the labyrinthine layer, suggesting that circulatory changes are integral to the altered phenotypes. PMID:28231241

Technical Note: Display window setting: An important factor for detecting subtle but clinically relevant artifacts in daily CT quality control.

PubMed

Long, Zaiyang; Bruesewitz, Michael R; Sheedy, Emily N; Powell, Michele A; Kramer, Jacqualynn C; Supalla, Randall R; Colvin, Chance M; Bechel, Jessica R; Favazza, Christopher P; Kofler, James M; Leng, Shuai; McCollough, Cynthia H; Yu, Lifeng

2016-12-01

This study aimed to investigate the influence of display window setting on technologist performance detecting subtle but clinically relevant artifacts in daily computed tomography (CT) quality control (dQC) images. Fifty three sets of dQC images were retrospectively selected, including 30 sets without artifacts, and 23 with subtle but clinically relevant artifacts. They were randomized and shown to six CT technologists (two new and four experienced). Each technologist reviewed all images in each of two sessions, one with a display window width (WW) of 100 HU, which is currently recommended by the American College of Radiology, and the other with a narrow WW of 40 HU, both at a window level of 0 HU. For each case, technologists rated the presence of image artifacts based on a five point scale. The area under the receiver operating characteristic curve (AUC) was used to evaluate the artifact detection performance. At a WW of 100 HU, the AUC (95% confidence interval) was 0.658 (0.576, 0.740), 0.532 (0.429, 0.635), and 0.616 (0.543, 0.619) for the experienced, new, and all technologists, respectively. At a WW of 40 HU, the AUC was 0.768 (0.687, 0.850), 0.546 (0.433, 0.658), and 0.694 (0.619, 0.769), respectively. The performance significantly improved at WW of 40 HU for experienced technologists (p = 0.009) and for all technologists (p = 0.040). Use of a narrow display WW significantly improved technologists' performance in dQC for detecting subtle but clinically relevant artifacts as compared to that using a 100 HU display WW.

Structural determinants of vascular resistance properties in hypertension. Haemodynamic and model analysis.

PubMed

Korner, P I; Angus, J A

1992-01-01

The average internal radius (ri) of the resistance vessels of the hindquarter (HQ) bed was narrower in renovascular and genetic hypertension than in normotensive controls. The narrowing was approximately uniform over the full range of vasomotor tone, which accounted for the bed's property as an 'amplifier' of vascular resistance (R) (increased slope (S) of the dose-R response curve) and for the elevated R at maximum dilatation (Rmin). In the model we examined the effects on the dose-R curve parameters of altering wall/internal radius (w/ri) ratio, ri and wall 'stiffness' one at a time, whilst the others were held constant: only narrowing of ri led to increases in both S and Rmin; with hypertrophy alone, S increased but Rmin was reduced, whilst increased wall stiffness increased Rmin but lowered S. Thus, for hypertrophy to be associated with rises of both S and Rmin, it must be linked to lumen narrowing, to increased wall stiffness, or to both. Preferential deposition of new material towards the lumen will link hypertrophy to narrowing. It has been suggested that narrowing can occur without hypertrophy ('remodelling'). In the model an increase of only 1-2% WV was required to produce rises in w/ri of congruent to 30-50% when associated with congruent to 10-15% reduction in ri, which is close to the limit of detection. From the literature, the sites of greater narrowing in hypertension extend down to small arteries and large arterioles. The rise in BP upstream from those sites, due to the vascular amplifier, offsets the down-stream effects of vascular narrowing on blood flow and this negative feedback system helps to maintain elevation of BP at a stable level. We also examined developmental rise in R between 4 and 50 weeks, which affected SHR and WKY in the same proportion: structural factors (vascular length of larger arteries, 'rarefaction' of arterioles and capillaries) accounted for only about half the rise in R, and the remainder was probably due to developmental changes in muscle function.

An Experiment in American Educational Philosophy

ERIC Educational Resources Information Center

Zahner, Mary

2016-01-01

The nineteenth century educational experiment by Amos Bronson Alcott and Elizabeth Palmer Peabody at the Temple School in Boston from 1834-1836 was generally considered a failure. Nevertheless, a narrow window of the experiment planted the seed for future interest in early childhood education by means of Peabody's (1836) "Record of a School:…

Low-Voltage Complementary Electronics from Ion-Gel-Gated Vertical Van der Waals Heterostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Yongsuk; Kang, Junmo; Jariwala, Deep

2016-03-22

Low-voltage complementary circuits comprising n-type and p-type van der Waals heterojunction vertical field-effect transistors (VFETs) are demonstrated. The resulting VFETs possess high on-state current densities (>3000 A cm-2) and on/off current ratios (>104) in a narrow voltage window (<3 V).

Equity and Excellence in Education Reform: An Unfinished Agenda.

ERIC Educational Resources Information Center

Sadker, Myra; Sadker, David

This paper argues that the recent wave of school reform literature has neglected females, thereby threatening to close already narrowing windows of opportunity for their advanced education beyond high school. A line-by-line content analysis of 138 articles on educational reform published in nine influential professional journals between 1983 and…

21. INTERIOR OF UTILITY ROOM SHOWING OPEN REAR DOOR AT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. INTERIOR OF UTILITY ROOM SHOWING OPEN REAR DOOR AT PHOTO CENTER, PAIRED NARROW 1-LIGHT OVER 1-LIGHT, DOUBLE-HUNG, WOOD-FRAMED WINDOWS AT PHOTO LEFT. OPEN DOOR AT PHOTO RIGHT LEADS TO BATHROOM. VIEW TO SOUTHWEST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

Clinical recommendation for treatment planning of sinus augmentation procedures by using presurgical CAT scan images: a preliminary report.

PubMed

Kutkut, Ahmad M; Andreana, Sebastiano; Kim, Hyeong-Ll; Monaco, Edward

2011-12-01

To propose a clinical recommendation based on anatomy of maxillary sinus before sinus augmentation procedure using presurgical computerized axial tomography (CAT) scan images. CAT scan images were randomly selected from previous completed implant cases. Proposed area for the lateral window osteotomy was outlined on the panorex image of the CAT scan. Sagittal section on the CAT scan that was in the center of the outlined window was selected for sinus measurement analysis. On CAT scan, 2 lines were drawn to measure the dimensions of sinus. One line measured the horizontal width and the other line measured the vertical height. Based on the measurement data, a classification of the maxillary sinus anatomy was proposed. Narrow sinus cavity indicates favorable type anatomy in terms of bone regeneration healing and wide sinus cavity as less favorable anatomy for patient treatment planning. A narrow sinus and greater exposure to the blood supply should require shorter healing times after grafting. Conversely, wider sinus cavities and less exposure to the blood supply would require a longer healing time before implant placement.

Germline and reproductive tract effects intensify in male mice with successive generations of estrogenic exposure

PubMed Central

Horan, Tegan S.; Marre, Alyssa; Hassold, Terry; Lawson, Crystal; Hunt, Patricia A.

2017-01-01

The hypothesis that developmental estrogenic exposure induces a constellation of male reproductive tract abnormalities is supported by experimental and human evidence. Experimental data also suggest that some induced effects persist in descendants of exposed males. These multi- and transgenerational effects are assumed to result from epigenetic changes to the germline, but few studies have directly analyzed germ cells. Typically, studies of transgenerational effects have involved exposing one generation and monitoring effects in subsequent unexposed generations. This approach, however, has limited human relevance, since both the number and volume of estrogenic contaminants has increased steadily over time, intensifying rather than reducing or eliminating exposure. Using an outbred CD-1 mouse model, and a sensitive and quantitative marker of germline development, meiotic recombination, we tested the effect of successive generations of exposure on the testis. We targeted the germline during a narrow, perinatal window using oral exposure to the synthetic estrogen, ethinyl estradiol. A complex three generation exposure protocol allowed us to compare the effects of individual, paternal, and grandpaternal (ancestral) exposure. Our data indicate that multiple generations of exposure not only exacerbate germ cell exposure effects, but also increase the incidence and severity of reproductive tract abnormalities. Taken together, our data suggest that male sensitivity to environmental estrogens is increased by successive generations of exposure. PMID:28727826

Hedgehog-responsive candidate cell of origin for diffuse intrinsic pontine glioma

PubMed Central

Monje, Michelle; Mitra, Siddhartha S.; Freret, Morgan E.; Raveh, Tal B.; Kim, James; Masek, Marilyn; Attema, Joanne L.; Haddix, Terri; Edwards, Michael S. B.; Fisher, Paul G.; Weissman, Irving L.; Rowitch, David H.; Vogel, Hannes; Wong, Albert J.; Beachy, Philip A.

2011-01-01

Diffuse intrinsic pontine gliomas (DIPGs) are highly aggressive tumors of childhood that are almost universally fatal. Our understanding of this devastating cancer is limited by a dearth of available tissue for study and by the lack of a faithful animal model. Intriguingly, DIPGs are restricted to the ventral pons and occur during a narrow window of middle childhood, suggesting dysregulation of a postnatal neurodevelopmental process. Here, we report the identification of a previously undescribed population of immunophenotypic neural precursor cells in the human and murine brainstem whose temporal and spatial distributions correlate closely with the incidence of DIPG and highlight a candidate cell of origin. Using early postmortem DIPG tumor tissue, we have established in vitro and xenograft models and find that the Hedgehog (Hh) signaling pathway implicated in many developmental and oncogenic processes is active in DIPG tumor cells. Modulation of Hh pathway activity has functional consequences for DIPG self-renewal capacity in neurosphere culture. The Hh pathway also appears to be active in normal ventral pontine precursor-like cells of the mouse, and unregulated pathway activity results in hypertrophy of the ventral pons. Together, these findings provide a foundation for understanding the cellular and molecular origins of DIPG, and suggest that the Hh pathway represents a potential therapeutic target in this devastating pediatric tumor. PMID:21368213

Thermohydraulic behavior of the liquid metal target of a spallation neutron source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeda, Y.

1996-06-01

The author presents work done on three main problems. (1) Natural circulation in double coaxial cylindircal container: The thermohydraulic behaviour of the liquid metal target of the spallation neutron source at PSI has been investigated. The configuration is a natural-circulation loop in a concentric double-tube-type container. The results show that the natural-circulation loop concept is valid for the design phase of the target construction, and the current specified design criteria will be fulfilled with the proposed parameter values. (2) Flow around the window: Water experiments were performed for geometry optimisation of the window shape of the SINQ container for avoidingmore » generating recirculation zones at peripheral area and the optimal cooling of the central part of the beam entrance window. Flow visualisation technique was mainly used for various window shapes, gap distance between the window and the guide tube edge. (3) Flow in window cooling channels: Flows in narrow gaps of cooling channels of two different types of windows were studied by flow visualisation techniques. One type is a slightly curved round cooling channel and the other is hemispherical shape, both of which have only 2 mm gap distance and the water inlet is located on one side and flows out from the opposite side. In both cases, the central part of the flow area has lower velocity than peripheral area.« less

Laser window with annular grooves for thermal isolation

DOEpatents

Warner, B.E.; Horton, J.A.; Alger, T.W.

1983-07-13

A laser window or other optical element which is thermally loaded, heats up and causes optical distortions because of temperature gradients between the center and the edge. A number of annular grooves, one to three or more, are formed in the element between a central portion and edge portion, producing a web portion which concentrates the thermal gradient and thermally isolates the central portion from the edge portion, producing a uniform temperature profile across the central portion and therefore reduce the optical distortions. The grooves are narrow and closely spaced with respect to the thickness of the element, and successive grooves are formed from alternate sides of the element.

Bayesian distributed lag interaction models to identify perinatal windows of vulnerability in children's health.

PubMed

Wilson, Ander; Chiu, Yueh-Hsiu Mathilda; Hsu, Hsiao-Hsien Leon; Wright, Robert O; Wright, Rosalind J; Coull, Brent A

2017-07-01

Epidemiological research supports an association between maternal exposure to air pollution during pregnancy and adverse children's health outcomes. Advances in exposure assessment and statistics allow for estimation of both critical windows of vulnerability and exposure effect heterogeneity. Simultaneous estimation of windows of vulnerability and effect heterogeneity can be accomplished by fitting a distributed lag model (DLM) stratified by subgroup. However, this can provide an incomplete picture of how effects vary across subgroups because it does not allow for subgroups to have the same window but different within-window effects or to have different windows but the same within-window effect. Because the timing of some developmental processes are common across subpopulations of infants while for others the timing differs across subgroups, both scenarios are important to consider when evaluating health risks of prenatal exposures. We propose a new approach that partitions the DLM into a constrained functional predictor that estimates windows of vulnerability and a scalar effect representing the within-window effect directly. The proposed method allows for heterogeneity in only the window, only the within-window effect, or both. In a simulation study we show that a model assuming a shared component across groups results in lower bias and mean squared error for the estimated windows and effects when that component is in fact constant across groups. We apply the proposed method to estimate windows of vulnerability in the association between prenatal exposures to fine particulate matter and each of birth weight and asthma incidence, and estimate how these associations vary by sex and maternal obesity status in a Boston-area prospective pre-birth cohort study. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Windows of sensitivity to toxic chemicals in the motor effects development.

PubMed

Ingber, Susan Z; Pohl, Hana R

2016-02-01

Many chemicals currently used are known to elicit nervous system effects. In addition, approximately 2000 new chemicals introduced annually have not yet undergone neurotoxicity testing. This review concentrated on motor development effects associated with exposure to environmental neurotoxicants to help identify critical windows of exposure and begin to assess data needs based on a subset of chemicals thoroughly reviewed by the Agency for Toxic Substances and Disease Registry (ATSDR) in Toxicological Profiles and Addenda. Multiple windows of sensitivity were identified that differed based on the maturity level of the neurological system at the time of exposure, as well as dose and exposure duration. Similar but distinct windows were found for both motor activity (GD 8-17 [rats], GD 12-14 and PND 3-10 [mice]) and motor function performance (insufficient data for rats, GD 12-17 [mice]). Identifying specific windows of sensitivity in animal studies was hampered by study designs oriented towards detection of neurotoxicity that occurred at any time throughout the developmental process. In conclusion, while this investigation identified some critical exposure windows for motor development effects, it demonstrates a need for more acute duration exposure studies based on neurodevelopmental windows, particularly during the exposure periods identified in this review. Published by Elsevier Inc.

Windows of sensitivity to toxic chemicals in the motor effects development✩

PubMed Central

Ingber, Susan Z.; Pohl, Hana R.

2017-01-01

Many chemicals currently used are known to elicit nervous system effects. In addition, approximately 2000 new chemicals introduced annually have not yet undergone neurotoxicity testing. This review concentrated on motor development effects associated with exposure to environmental neurotoxicants to help identify critical windows of exposure and begin to assess data needs based on a subset of chemicals thoroughly reviewed by the Agency for Toxic Substances and Disease Registry (ATSDR) in Toxicological Profiles and Addenda. Multiple windows of sensitivity were identified that differed based on the maturity level of the neurological system at the time of exposure, as well as dose and exposure duration. Similar but distinct windows were found for both motor activity (GD 8–17 [rats], GD 12–14 and PND 3–10 [mice]) and motor function performance (insufficient data for rats, GD 12–17 [mice]). Identifying specific windows of sensitivity in animal studies was hampered by study designs oriented towards detection of neurotoxicity that occurred at any time throughout the developmental process. In conclusion, while this investigation identified some critical exposure windows for motor development effects, it demonstrates a need for more acute duration exposure studies based on neurodevelopmental windows, particularly during the exposure periods identified in this review. PMID:26686904

The Effect of Working Memory Capacity Limitations on the Intuitive Assessment of Correlation: Amplification, Attenuation, or Both?

ERIC Educational Resources Information Center

Cahan, Sorel; Mor, Yaniv

2007-01-01

This article challenges Yaakov Kareev's (1995a, 2000) argument regarding the positive bias of intuitive correlation estimates due to working memory capacity limitations and its adaptive value. The authors show that, under narrow window theory's primacy effect assumption, there is a considerable between-individual variability of the effects of…

Estimating fuel consumption for the upper coastal plain of South Carolina

Treesearch

S.L. Goodrick; D. Shea; J. Blake

2010-01-01

Recent changes in air quality regulations present a potential obstacle to continued use of prescribed fire as a land management tool. towering of the acceptable daily concentration of particulate matter from 6510 35 jig/m' will bring much closer scrutiny of prescribed burning practices from the air quality community. To work within this narrow window, land...

Optical Filter Assembly for Interplanetary Optical Communications

NASA Technical Reports Server (NTRS)

Chen, Yijiang; Hemmati, Hamid

2013-01-01

Ground-based, narrow-band, high throughput optical filters are required for optical links from deep space. We report on the development of a tunable filter assembly that operates at telecommunication window of 1550 nanometers. Low insertion loss of 0.5 decibels and bandwidth of 90 picometers over a 2000 nanometers operational range of detectors has been achieved.

An assessment of prewhitening in estimating power spectra of atmospheric turbulence at long wavelengths

NASA Technical Reports Server (NTRS)

Keisler, S. R.; Rhyne, R. H.

1976-01-01

Synthetic time histories were generated and used to assess the effects of prewhitening on the long wavelength portion of power spectra of atmospheric turbulence. Prewhitening is not recommended when using the narrow spectral windows required for determining power spectral estimates below the 'knee' frequency, that is, at very long wavelengths.

Transparency of 2μ m window of Titan's atmosphere

NASA Astrophysics Data System (ADS)

Rannou, P.; Seignovert, B.; Le Mouélic, S.; Maltagliati, L.; Rey, M.; Sotin, C.

2018-02-01

Titan's atmosphere is optically thick and hides the surface and the lower layers from the view at almost all wavelengths. However, because gaseous absorptions are spectrally selective, some narrow spectral intervals are relatively transparent and allow to probe the surface. To use these intervals (called windows) a good knowledge of atmospheric absorption is necessary. Once gas spectroscopic linelists are well established, the absorption inside windows depends on the way the far wings of the methane absorption lines are cut-off. We know that the intensity in all the windows can be explained with the same cut-off parameters, except for the window at 2 μm. This discrepancy is generally treated with a workaround which consists in using a different cut-off description for this specific window. This window is relatively transparent and surface may have specific spectral signatures that could be detected. Thus, a good knowledge of atmosphere opacities is essential and our scope is to better understand what causes the difference between the 2 μm window and the other windows. In this work, we used scattered light at the limb and transmissions in occultation observed with VIMS (Visual Infrared Mapping Spectrometer) onboard Cassini, around the 2 μm window. Data shows an absorption feature that participates to the shape of this window. Our atmospheric model fits well the VIMS data at 2 μm with the same cut-off than for the other windows, provided an additional absorption is introduced in the middle of the window around ≃ 2.065 μm. It explains well the discrepency between the cut-off used at 2 μm, and we show that a gas with a fairly constant mixing ratio, possibly ethane, may be the cause of this absorption. Finally, we studied the impact of this absorption on the retrieval of the surface reflectivity and found that it is significant.

Computational model for behavior shaping as an adaptive health intervention strategy.

PubMed

Berardi, Vincent; Carretero-González, Ricardo; Klepeis, Neil E; Ghanipoor Machiani, Sahar; Jahangiri, Arash; Bellettiere, John; Hovell, Melbourne

2018-03-01

Adaptive behavioral interventions that automatically adjust in real-time to participants' changing behavior, environmental contexts, and individual history are becoming more feasible as the use of real-time sensing technology expands. This development is expected to improve shortcomings associated with traditional behavioral interventions, such as the reliance on imprecise intervention procedures and limited/short-lived effects. JITAI adaptation strategies often lack a theoretical foundation. Increasing the theoretical fidelity of a trial has been shown to increase effectiveness. This research explores the use of shaping, a well-known process from behavioral theory for engendering or maintaining a target behavior, as a JITAI adaptation strategy. A computational model of behavior dynamics and operant conditioning was modified to incorporate the construct of behavior shaping by adding the ability to vary, over time, the range of behaviors that were reinforced when emitted. Digital experiments were performed with this updated model for a range of parameters in order to identify the behavior shaping features that optimally generated target behavior. Narrowing the range of reinforced behaviors continuously in time led to better outcomes compared with a discrete narrowing of the reinforcement window. Rapid narrowing followed by more moderate decreases in window size was more effective in generating target behavior than the inverse scenario. The computational shaping model represents an effective tool for investigating JITAI adaptation strategies. Model parameters must now be translated from the digital domain to real-world experiments so that model findings can be validated.

Developmental milestones among Aboriginal children in Canada

PubMed Central

Findlay, Leanne; Kohen, Dafna; Miller, Anton

2014-01-01

BACKGROUND: Windows of achievement provide age ranges for the attainment of early developmental skills. Group-specific research is warranted given that development may be influenced by social or cultural factors. OBJECTIVES: To examine developmental milestones for Inuit, Métis and off-reserve First Nation children in Canada, based on developmental domains collected from the 2006 Aboriginal Children’s Survey. Sociodemographic and health predictors of risk for developmental delay were also examined. RESULTS: The ranges in which children achieve certain developmental milestones are presented. Gross motor and self-help skills were found to be achieved earlier (across the three Aboriginal groups), whereas language skills were achieved slightly later than in Canadian children in general. Furthermore, health factors (eg, low birth weight, chronic health conditions) were associated with late achievement of developmental outcomes even when sociodemographic characteristics were considered. CONCLUSIONS: Findings suggest that the timing of milestone achievement may differ for Aboriginal children, highlighting the importance of establishing culturally specific norms and standards rather than relying on those derived from general populations. This information may be useful for practitioners and parents interested in identifying the age ranges for development, as well as age ranges indicating potential for developmental risk and opportunities for early intervention among Aboriginal children. PMID:24855426

Detection with Enhanced Energy Windowing Phase I Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bass, David A.; Enders, Alexander L.

2016-12-01

This document reviews the progress of Phase I of the Detection with Enhanced Energy Windowing (DEEW) project. The DEEW project is the implementation of software incorporating an algorithm which reviews data generated by radiation portal monitors and utilizes advanced and novel techniques for detecting radiological and fissile material while not alarming on Naturally Occurring Radioactive Material. Independent testing indicated that the Enhanced Energy Windowing algorithm showed promise at reducing the probability of alarm in the stream of commerce compared to existing algorithms and other developmental algorithms, while still maintaining adequate sensitivity to threats. This document contains a brief description ofmore » the project, instructions for setting up and running the applications, and guidance to help make reviewing the output files and source code easier.« less

Emile's Moral Development. A Rousseauan Perspective on Kohlberg.

ERIC Educational Resources Information Center

Simpson, Evan

1983-01-01

Uses Rousseau's "Emile" to explicate Kohlberg's characterization of moral development and to illuminate several theoretical problems in Kohlberg's cognitive-developmental account. Analysis supports contentions that Kohlberg's concept of morality is unduly narrow and suggests that his one-sidedly rationalistic approach exaggerates the…

Displacement and frequency analyses of vibratory systems

NASA Astrophysics Data System (ADS)

Low, K. H.

1995-02-01

This paper deals with the frequency and response studies of vibratory systems, which are represented by a set of n coupled second-order differential equations. The following numerical methods are used in the response analysis: central difference, fourth-order Runge-Kutta and modal methods. Data generated in the response analysis are processed to obtain the system frequencies by using the fast Fourier transform (FFT) or harmonic response methods. Two types of the windows are used in the FFT analysis: rectangular and Hanning windows. Examples of two, four and seven degrees of freedom systems are considered, to illustrate the proposed algorithms. Comparisons with those existing results confirm the validity of the proposed methods. The Hanning window attenuates the results that give a narrower bandwidth around the peak if compared with those using the rectangular window. It is also found that in free vibrations of a multi-mass system, the masses will vibrate in a manner that is the superposition of the natural frequencies of the system, while the system will vibrate at the driving frequency in forced vibrations.

Online frequency estimation with applications to engine and generator sets

NASA Astrophysics Data System (ADS)

Manngård, Mikael; Böling, Jari M.

2017-07-01

Frequency and spectral analysis based on the discrete Fourier transform is a fundamental task in signal processing and machine diagnostics. This paper aims at presenting computationally efficient methods for real-time estimation of stationary and time-varying frequency components in signals. A brief survey of the sliding time window discrete Fourier transform and Goertzel filter is presented, and two filter banks consisting of: (i) sliding time window Goertzel filters (ii) infinite impulse response narrow bandpass filters are proposed for estimating instantaneous frequencies. The proposed methods show excellent results on both simulation studies and on a case study using angular speed data measurements of the crankshaft of a marine diesel engine-generator set.

Generation of tunable double Fano resonances by plasmon hybridization in graphene–metal metamaterial

NASA Astrophysics Data System (ADS)

Yan, Zhendong; Qian, Lina; Zhan, Peng; Wang, Zhenlin

2018-07-01

We proposed the excitation of double Fano resonances by the destructive interference between the narrow electric symmetric/antisymmetric resonant modes formed by plasmon hybridization and a broad magnetic dipole resonance in a novel hybrid metamaterial composed of periodically patterned stacked graphene–ribbon pairs and gold split-ring resonators. The double Fano transparency windows in this hybrid metamaterial can be actively controlled by tuning the Fermi energy of graphene through the use of electric gating and its electronic mobility. Our designed dual Fano resonances exhibit a large group index associated with the resonance response in the transparency windows, suggesting promising applications in nanophotonics, such as a slow light device.

Critical disease windows shaped by stress exposure alter allocation trade-offs between development and immunity.

PubMed

Kirschman, Lucas J; Crespi, Erica J; Warne, Robin W

2018-01-01

Ubiquitous environmental stressors are often thought to alter animal susceptibility to pathogens and contribute to disease emergence. However, duration of exposure to a stressor is likely critical, because while chronic stress is often immunosuppressive, acute stress can temporarily enhance immune function. Furthermore, host susceptibility to stress and disease often varies with ontogeny; increasing during critical developmental windows. How the duration and timing of exposure to stressors interact to shape critical windows and influence disease processes is not well tested. We used ranavirus and larval amphibians as a model system to investigate how physiological stress and pathogenic infection shape development and disease dynamics in vertebrates. Based on a resource allocation model, we designed experiments to test how exposure to stressors may induce resource trade-offs that shape critical windows and disease processes because the neuroendocrine stress axis coordinates developmental remodelling, immune function and energy allocation in larval amphibians. We used wood frog larvae (Lithobates sylvaticus) to investigate how chronic and acute exposure to corticosterone, the dominant amphibian glucocorticoid hormone, mediates development and immune function via splenocyte immunohistochemistry analysis in association with ranavirus infection. Corticosterone treatments affected immune function, as both chronic and acute exposure suppressed splenocyte proliferation, although viral replication rate increased only in the chronic corticosterone treatment. Time to metamorphosis and survival depended on both corticosterone treatment and infection status. In the control and chronic corticosterone treatments, ranavirus infection decreased survival and delayed metamorphosis, although chronic corticosterone exposure accelerated rate of metamorphosis in uninfected larvae. Acute corticosterone exposure accelerated metamorphosis increased survival in infected larvae. Interactions between stress exposure (via glucocorticoid actions) and infection impose resource trade-offs that shape optimal allocation between development and somatic function. As a result, critical disease windows are likely shaped by stress exposure because any conditions that induce changes in differentiation rates will alter the duration and susceptibility of organisms to stressors or disease. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Developmental windows of breast cancer risk provide opportunities for targeted chemoprevention

PubMed Central

Martinson, Holly A.; Lyons, Traci R.; Giles, Erin D.; Borges, Virginia F.; Schedin, Pepper

2014-01-01

The magnitude of the breast cancer problem implores researchers to aggressively investigate prevention strategies. However, several barriers currently reduce the feasibility of breast cancer prevention. These barriers include the inability to accurately predict future breast cancer diagnosis at the individual level, the need for improved understanding of when to implement interventions, uncertainty with respect to optimal duration of treatment, and negative side effects associated with currently approved chemoprevention therapies. None-the-less, the unique biology of the mammary gland, with its postnatal development and conditional terminal differentiation, may permit the resolution of many of these barriers. Specifically, lifecycle-specific windows of breast cancer risk have been identified that may be amenable to risk-reducing strategies. Here, we argue for prevention research focused on two of these lifecycle windows of risk: postpartum mammary gland involution and peri-menopause. We provide evidence that these windows are highly amenable to targeted, limited duration treatments. Such approaches could result in the prevention of postpartum and postmenopausal breast cancers, correspondingly. PMID:23664839

Worldwide variability in growth and its association with health: Incorporating body composition, developmental plasticity, and intergenerational effects.

PubMed

Wells, Jonathan C K

2017-03-01

In their seminal book "Worldwide variation in human growth," published in 1976, Eveleth and Tanner highlighted substantial variability within and between populations in the magnitude and schedule of human growth. In the four decades since then, research has clarified why growth variability is so closely associated with human health. First, growth patterns are strongly associated with body composition, both in the short- and long-term. Poor growth in early life constrains the acquisition of lean tissue, while compensatory "catch-up" growth may elevate body fatness. Second, these data are examples of the fundamental link between growth and developmental plasticity. Growth is highly sensitive to ecological stresses and stimuli during early "critical windows," but loses much of this sensitivity as it undergoes canalization during early childhood. Crucially, the primary source of stimuli during early "critical windows" is not the external environment itself, but rather maternal phenotype, which transduces the impact of ecological conditions. Maternal phenotype, representing many dimensions of "capital," thus generates a powerful impact on the developmental trajectory of the offspring. There is increasing evidence that low levels of maternal capital impact the offspring's size at birth, schedule of maturation, and body composition and physiological function in adulthood. While evidence has accrued of substantial heritability in adult height, it is clear that the pathway through which it is attained has major implications for metabolic phenotype. Integrating these perspectives is important for understanding how developmental plasticity may on the one hand contribute to adaptation, while on the other shape susceptibility to non-communicable disease. © 2017 Wiley Periodicals, Inc.

Optimizing the location of fuel treatments over time at landscape scales

Treesearch

Greg Jones; Woodam Chung

2011-01-01

Fuel treatments are a vital part of forest management - but when faced with limited budgets, narrow burning windows, and air quality restrictions, it can be challenging to prioritize where, when, and how fuel treatments should be applied across the landscape to achieve the most benefi t. To help ease this process, land managers can turn to various standalone models,...

Surface Emissivity Maps for Use in Satellite Retrievals of Longwave Radiation

NASA Technical Reports Server (NTRS)

Wilber, Anne C.; Kratz, David P.; Gupta, Shashi K.

1999-01-01

Accurate accounting of surface emissivity is essential for the retrievals of surface temperature from remote sensing measurements, and for the computations of longwave (LW) radiation budget of the Earth?s surface. Past studies of the above topics assumed that emissivity for all surface types, and across the entire LW spectrum is equal to unity. There is strong evidence, however, that emissivity of many surface materials is significantly lower than unity, and varies considerably across the LW spectrum. We have developed global maps of surface emissivity for the broadband LW region, the thermal infrared window region (8-12 micron), and 12 narrow LW spectral bands. The 17 surface types defined by the International Geosphere Biosphere Programme (IGBP) were adopted as such, and an additional (18th) surface type was introduced to represent tundra-like surfaces. Laboratory measurements of spectral reflectances of 10 different surface materials were converted to corresponding emissivities. The 10 surface materials were then associated with 18 surface types. Emissivities for the 18 surface types were first computed for each of the 12 narrow spectral bands. Emissivities for the broadband and the window region were then constituted from the spectral band values by weighting them with Planck function energy distribution.

Abscisic acid (ABA) sensitivity regulates desiccation tolerance in germinated Arabidopsis seeds.

PubMed

Maia, Julio; Dekkers, Bas J W; Dolle, Miranda J; Ligterink, Wilco; Hilhorst, Henk W M

2014-07-01

During germination, orthodox seeds lose their desiccation tolerance (DT) and become sensitive to extreme drying. Yet, DT can be rescued, in a well-defined developmental window, by the application of a mild osmotic stress before dehydration. A role for abscisic acid (ABA) has been implicated in this stress response and in DT re-establishment. However, the path from the sensing of an osmotic cue and its signaling to DT re-establishment is still largely unknown. Analyses of DT, ABA sensitivity, ABA content and gene expression were performed in desiccation-sensitive (DS) and desiccation-tolerant Arabidopsis thaliana seeds. Furthermore, loss and re-establishment of DT in germinated Arabidopsis seeds was studied in ABA-deficient and ABA-insensitive mutants. We demonstrate that the developmental window in which DT can be re-established correlates strongly with the window in which ABA sensitivity is still present. Using ABA biosynthesis and signaling mutants, we show that this hormone plays a key role in DT re-establishment. Surprisingly, re-establishment of DT depends on the modulation of ABA sensitivity rather than enhanced ABA content. In addition, the evaluation of several ABA-insensitive mutants, which can still produce normal desiccation-tolerant seeds, but are impaired in the re-establishment of DT, shows that the acquisition of DT during seed development is genetically different from its re-establishment during germination. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

An Efficient Adaptive Window Size Selection Method for Improving Spectrogram Visualization.

PubMed

Nisar, Shibli; Khan, Omar Usman; Tariq, Muhammad

2016-01-01

Short Time Fourier Transform (STFT) is an important technique for the time-frequency analysis of a time varying signal. The basic approach behind it involves the application of a Fast Fourier Transform (FFT) to a signal multiplied with an appropriate window function with fixed resolution. The selection of an appropriate window size is difficult when no background information about the input signal is known. In this paper, a novel empirical model is proposed that adaptively adjusts the window size for a narrow band-signal using spectrum sensing technique. For wide-band signals, where a fixed time-frequency resolution is undesirable, the approach adapts the constant Q transform (CQT). Unlike the STFT, the CQT provides a varying time-frequency resolution. This results in a high spectral resolution at low frequencies and high temporal resolution at high frequencies. In this paper, a simple but effective switching framework is provided between both STFT and CQT. The proposed method also allows for the dynamic construction of a filter bank according to user-defined parameters. This helps in reducing redundant entries in the filter bank. Results obtained from the proposed method not only improve the spectrogram visualization but also reduce the computation cost and achieves 87.71% of the appropriate window length selection.

The Liguleless narrow mutation affects proximal distal signaling and leaf growth

USDA-ARS?s Scientific Manuscript database

How cells acquire competence to differentiate according to position is an essential question in developmental biology. Maize leaves provide a unique opportunity to study positional information. In the developing leaf primordium, a line is drawn across a field of seemingly identical cells. Above the ...

The Utility of Stage-specific Mid-to-late Drosophila Follicle Isolation

PubMed Central

Spracklen, Andrew J.; Tootle, Tina L.

2013-01-01

Drosophila oogenesis or follicle development has been widely used to advance the understanding of complex developmental and cell biologic processes. This methods paper describes how to isolate mid-to-late stage follicles (Stage 10B-14) and utilize them to provide new insights into the molecular and morphologic events occurring during tight windows of developmental time. Isolated follicles can be used for a variety of experimental techniques, including in vitro development assays, live imaging, mRNA expression analysis and western blot analysis of proteins. Follicles at Stage 10B (S10B) or later will complete development in culture; this allows one to combine genetic or pharmacologic perturbations with in vitro development to define the effects of such manipulations on the processes occurring during specific periods of development. Additionally, because these follicles develop in culture, they are ideally suited for live imaging studies, which often reveal new mechanisms that mediate morphological events. Isolated follicles can also be used for molecular analyses. For example, changes in gene expression that result from genetic perturbations can be defined for specific developmental windows. Additionally, protein level, stability, and/or posttranslational modification state during a particular stage of follicle development can be examined through western blot analyses. Thus, stage-specific isolation of Drosophila follicles provides a rich source of information into widely conserved processes of development and morphogenesis. PMID:24326735

Specification of hepatopancreas progenitors in zebrafish by hnf1ba and wnt2bb

PubMed Central

Lancman, Joseph J.; Zvenigorodsky, Natasha; Gates, Keith P.; Zhang, Danhua; Solomon, Keely; Humphrey, Rohan K.; Kuo, Taiyi; Setiawan, Linda; Verkade, Heather; Chi, Young-In; Jhala, Ulupi S.; Wright, Christopher V. E.; Stainier, Didier Y. R.; Dong, P. Duc Si

2013-01-01

Although the liver and ventral pancreas are thought to arise from a common multipotent progenitor pool, it is unclear whether these progenitors of the hepatopancreas system are specified by a common genetic mechanism. Efforts to determine the role of Hnf1b and Wnt signaling in this crucial process have been confounded by a combination of factors, including a narrow time frame for hepatopancreas specification, functional redundancy among Wnt ligands, and pleiotropic defects caused by either severe loss of Wnt signaling or Hnf1b function. Using a novel hypomorphic hnf1ba zebrafish mutant that exhibits pancreas hypoplasia, as observed in HNF1B monogenic diabetes, we show that hnf1ba plays essential roles in regulating β-cell number and pancreas specification, distinct from its function in regulating pancreas size and liver specification, respectively. By combining Hnf1ba partial loss of function with conditional loss of Wnt signaling, we uncover a crucial developmental window when these pathways synergize to specify the entire ventrally derived hepatopancreas progenitor population. Furthermore, our in vivo genetic studies demonstrate that hnf1ba generates a permissive domain for Wnt signaling activity in the foregut endoderm. Collectively, our findings provide a new model for HNF1B function, yield insight into pancreas and β-cell development, and suggest a new mechanism for hepatopancreatic specification. PMID:23720049

Constructing Sexuality and Identity in an Online Teen Chat Room

ERIC Educational Resources Information Center

Subrahmanyam, K.; Greenfield, P. M.; Tynes, B.

2004-01-01

In this article, we propose that adolescents' online interactions are both a literal and a metaphoric screen for representing major adolescent developmental issues, such as sexuality and identity. Because of the public nature of Internet chat rooms, they provide an open window into the expression of adolescent concerns. Our study utilizes this…

Neuroimaging: A Window to the Neurological Foundations of Learning and Behavior in Children.

ERIC Educational Resources Information Center

Lyon, G. Reid, Ed.; Rumsey, Judith M., Ed.

This book presents 11 papers on the use of neuroimaging technology in brain-related disorders. The text contains full-color neuroimaging scans and provides both theoretical and methodological explanations of the various neuroimaging techniques and their application to developmental disorders in children. The papers are grouped into three sections,…

Oxygen--a limiting factor for brain recovery.

PubMed

Hadanny, Amir; Efrati, Shai

2015-09-01

Effective brain metabolism is highly dependent on a narrow therapeutic window of oxygen. In major insults to the brain (e.g., intracerebral hemorrhage), a slight decrease in oxygen supply, as occurs in a hypobaric environment at high altitude, has devastating effects on the injured brain tissue. Conversely, increasing brain oxygenation, by the use of hyperbaric oxygen therapy, can improve brain metabolism and its dependent regenerative processes.

The Crista Fenestra and Its Impact on the Surgical Approach to the Scala Tympani during Cochlear Implantation.

PubMed

Angeli, Roberto D; Lavinsky, Joel; Setogutti, Enio T; Lavinsky, Luiz

2017-01-01

The aim of this work was to describe the dimensions of the crista fenestra and determine its presence by means of high-resolution computed tomography (CT) for the purpose of cochlear implantation via the round window approach. A series of 10 adult human temporal bones underwent high-resolution CT scanning and were further dissected for microscopic study of the round window niche. In all of the specimens, the round window membrane was fully visualized after the complete removal of bony overhangs. The crista fenestra was identified as a sharp bony crest located in the anterior and inferior borders of the niche; its area ranged from 0.28 to 0.80 mm2 (mean 0.51 ± 0.18). The proportion of the area occupied by the crista fenestra in the whole circumference of the round window ranged from 23 to 50% (mean 36%). We found a moderate positive correlation between the area of the niche and the dimensions of the crista fenestra (Spearman rho: 0.491). In every case, high-resolution CT scanning was unable to determine the presence of the crista fenestra. The crista fenestra occupies a variable but expressive area within the bony round window niche. Narrower round window niches tended to house smaller crests. The presence of the crista fenestra is an important obstacle to adequate access to the scala tympani. Nevertheless, a high-resolution CT scan provides no additional preoperative information with regard to its presence for the purpose of surgical access to the scala tympani via the round window niche. © 2017 S. Karger AG, Basel.

Fear, Worry, and Ritualistic Behaviour in Childhood: Developmental Trends and Interrelations

ERIC Educational Resources Information Center

Laing, Sarah V.; Fernyhough, Charles; Turner, Michelle; Freeston, Mark H.

2009-01-01

Previous studies of childhood fear, worry, and ritualistic behaviour have been limited by restricted age ranges, narrow ranges of anxiety phenomena, non-comparable methodologies, and assessment of typical behaviour within a pathological context. Content and intensity of fear, worry, and ritualistic behaviour, and associations among these…

Flexibility in Bilingual Infants' Word Learning

ERIC Educational Resources Information Center

Graf Estes, Katharine; Hay, Jessica F.

2015-01-01

The present experiments tested bilingual infants' developmental narrowing for the interpretation of sounds that form words. These studies addressed how language specialization proceeds when the environment provides varied and divergent input. Experiment 1 (N = 32) demonstrated that bilingual 14- and 19-month-olds learned a pair of object labels…

Temporal dynamics of figure-ground segregation in human vision.

PubMed

Neri, Peter; Levi, Dennis M

2007-01-01

The segregation of figure from ground is arguably one of the most fundamental operations in human vision. Neural signals reflecting this operation appear in cortex as early as 50 ms and as late as 300 ms after presentation of a visual stimulus, but it is not known when these signals are used by the brain to construct the percepts of figure and ground. We used psychophysical reverse correlation to identify the temporal window for figure-ground signals in human perception and found it to lie within the range of 100-160 ms. Figure enhancement within this narrow temporal window was transient rather than sustained as may be expected from measurements in single neurons. These psychophysical results prompt and guide further electrophysiological studies.

Latency as a region contrast: Measuring ERP latency differences with Dynamic Time Warping.

PubMed

Zoumpoulaki, A; Alsufyani, A; Filetti, M; Brammer, M; Bowman, H

2015-12-01

Methods for measuring onset latency contrasts are evaluated against a new method utilizing the dynamic time warping (DTW) algorithm. This new method allows latency to be measured across a region instead of single point. We use computer simulations to compare the methods' power and Type I error rates under different scenarios. We perform per-participant analysis for different signal-to-noise ratios and two sizes of window (broad vs. narrow). In addition, the methods are tested in combination with single-participant and jackknife average waveforms for different effect sizes, at the group level. DTW performs better than the other methods, being less sensitive to noise as well as to placement and width of the window selected. © 2015 Society for Psychophysiological Research.

Brief daily exposures to Asian females reverses perceptual narrowing for Asian faces in Caucasian infants

PubMed Central

Anzures, Gizelle; Wheeler, Andrea; Quinn, Paul C.; Pascalis, Olivier; Slater, Alan M.; Heron-Delaney, Michelle; Tanaka, James W.; Lee, Kang

2012-01-01

Perceptual narrowing in the visual, auditory, and multisensory domains has its developmental origins in infancy. The present study shows that experimentally induced experience can reverse the effects of perceptual narrowing on infants’ visual recognition memory of other-race faces. Caucasian 8- to 10-month-olds who could not discriminate between novel and familiarized Asian faces at the beginning of testing were given brief daily experience with Asian female faces in the experimental condition and Caucasian female faces in the control condition. At the end of three weeks, only infants who received daily experience with Asian females showed above-chance recognition of novel Asian female and male faces. Further, infants in the experimental condition showed greater efficiency in learning novel Asian females compared to infants in the control condition. Thus, visual experience with a novel stimulus category can reverse the effects of perceptual narrowing in infancy via improved stimulus recognition and encoding. PMID:22625845

Neural Correlates of Multisensory Perceptual Learning

PubMed Central

Powers, Albert R.; Hevey, Matthew A.; Wallace, Mark T.

2012-01-01

The brain’s ability to bind incoming auditory and visual stimuli depends critically on the temporal structure of this information. Specifically, there exists a temporal window of audiovisual integration within which stimuli are highly likely to be perceived as part of the same environmental event. Several studies have described the temporal bounds of this window, but few have investigated its malleability. Recently, our laboratory has demonstrated that a perceptual training paradigm is capable of eliciting a 40% narrowing in the width of this window that is stable for at least one week after cessation of training. In the current study we sought to reveal the neural substrates of these changes. Eleven human subjects completed an audiovisual simultaneity judgment training paradigm, immediately before and after which they performed the same task during an event-related 3T fMRI session. The posterior superior temporal sulcus (pSTS) and areas of auditory and visual cortex exhibited robust BOLD decreases following training, and resting state and effective connectivity analyses revealed significant increases in coupling among these cortices after training. These results provide the first evidence of the neural correlates underlying changes in multisensory temporal binding and that likely represent the substrate for a multisensory temporal binding window. PMID:22553032

From Mice to Men: research models of developmental programming

PubMed Central

Rabadán-Diehl, C.; Nathanielsz, P.

2012-01-01

Developmental programming can be defined as a response to a specific challenge to the mammalian organism during a critical developmental time window that alters the trajectory of development with persistent effects on offspring phenotype and predisposition to future illness. We focus on the need for studies in relevant, well-characterized animal models in the context of recent research discoveries on the challenges, mechanisms and outcomes of developmental programming. We discuss commonalities and differences in general principles of developmental programming as they apply to several species, including humans. The consequences of these differences are discussed. Obesity, metabolic disorders and cardiovascular diseases are associated with the highest percentage of morbidity and mortality worldwide. Although many of the causes are associated with lifestyle, high-energy diets and lack of physical activity, recent evidence has linked developmental programming to the epidemic of metabolic diseases. A better understanding of comparative systems physiology of mother, fetus and neonate using information provided by rapid advances in molecular biology has the potential to improve the lifetime health of future generations by providing better women’s health, diagnostic tools and preventative and therapeutic interventions in individuals exposed during their development to programming influences. PMID:23525085

A Motor-Skills Programme to Enhance Visual Motor Integration of Selected Pre-School Learners

ERIC Educational Resources Information Center

Africa, Eileen K.; van Deventer, Karel J.

2017-01-01

Pre-schoolers are in a window period for motor skill development. Visual-motor integration (VMI) is the foundation for academic and sport skills. Therefore, it must develop before formal schooling. This study attempted to improve VMI skills. VMI skills were measured with the "Beery-Buktenica developmental test of visual-motor integration 6th…

Accurate identification of microseismic P- and S-phase arrivals using the multi-step AIC algorithm

NASA Astrophysics Data System (ADS)

Zhu, Mengbo; Wang, Liguan; Liu, Xiaoming; Zhao, Jiaxuan; Peng, Ping'an

2018-03-01

Identification of P- and S-phase arrivals is the primary work in microseismic monitoring. In this study, a new multi-step AIC algorithm is proposed. This algorithm consists of P- and S-phase arrival pickers (P-picker and S-picker). The P-picker contains three steps: in step 1, a preliminary P-phase arrival window is determined by the waveform peak. Then a preliminary P-pick is identified using the AIC algorithm. Finally, the P-phase arrival window is narrowed based on the above P-pick. Thus the P-phase arrival can be identified accurately by using the AIC algorithm again. The S-picker contains five steps: in step 1, a narrow S-phase arrival window is determined based on the P-pick and the AIC curve of amplitude biquadratic time-series. In step 2, the S-picker automatically judges whether the S-phase arrival is clear to identify. In step 3 and 4, the AIC extreme points are extracted, and the relationship between the local minimum and the S-phase arrival is researched. In step 5, the S-phase arrival is picked based on the maximum probability criterion. To evaluate of the proposed algorithm, a P- and S-picks classification criterion is also established based on a source location numerical simulation. The field data tests show a considerable improvement of the multi-step AIC algorithm in comparison with the manual picks and the original AIC algorithm. Furthermore, the technique is independent of the kind of SNR. Even in the poor-quality signal group which the SNRs are below 5, the effective picking rates (the corresponding location error is <15 m) of P- and S-phase arrivals are still up to 80.9% and 76.4% respectively.

Acts of Writing: A Compilation of Six Models That Define the Processes of Writing

ERIC Educational Resources Information Center

Sharp, Laurie A.

2016-01-01

Writing is a developmental and flexible process. Using a prescribed process for acts of writing during instruction does not take into account individual differences of writers and generates writing instruction that is narrow, rigid, and inflexible. Preservice teachers receive limited training with theory and pedagogy for writing, which potentially…

Improved Learning in Aging: Implications for Education.

ERIC Educational Resources Information Center

Kramer, Deirdre A.

Three types of lay theories about the social world form a developmental sequence. Earlier developing theories are reorganized at the next level into a more inclusive, encompassing view of the world in order to make better predictions. The absolute thinker sees the world as fixed and unchanging, reasons with absolute rules, and has a narrow world…

Identifying Stable Reference Genes for qRT-PCR Normalisation in Gene Expression Studies of Narrow-Leafed Lupin (Lupinus angustifolius L.).

PubMed

Taylor, Candy M; Jost, Ricarda; Erskine, William; Nelson, Matthew N

2016-01-01

Quantitative Reverse Transcription PCR (qRT-PCR) is currently one of the most popular, high-throughput and sensitive technologies available for quantifying gene expression. Its accurate application depends heavily upon normalisation of gene-of-interest data with reference genes that are uniformly expressed under experimental conditions. The aim of this study was to provide the first validation of reference genes for Lupinus angustifolius (narrow-leafed lupin, a significant grain legume crop) using a selection of seven genes previously trialed as reference genes for the model legume, Medicago truncatula. In a preliminary evaluation, the seven candidate reference genes were assessed on the basis of primer specificity for their respective targeted region, PCR amplification efficiency, and ability to discriminate between cDNA and gDNA. Following this assessment, expression of the three most promising candidates [Ubiquitin C (UBC), Helicase (HEL), and Polypyrimidine tract-binding protein (PTB)] was evaluated using the NormFinder and RefFinder statistical algorithms in two narrow-leafed lupin lines, both with and without vernalisation treatment, and across seven organ types (cotyledons, stem, leaves, shoot apical meristem, flowers, pods and roots) encompassing three developmental stages. UBC was consistently identified as the most stable candidate and has sufficiently uniform expression that it may be used as a sole reference gene under the experimental conditions tested here. However, as organ type and developmental stage were associated with greater variability in relative expression, it is recommended using UBC and HEL as a pair to achieve optimal normalisation. These results highlight the importance of rigorously assessing candidate reference genes for each species across a diverse range of organs and developmental stages. With emerging technologies, such as RNAseq, and the completion of valuable transcriptome data sets, it is possible that other potentially more suitable reference genes will be identified for this species in future.

Identifying Stable Reference Genes for qRT-PCR Normalisation in Gene Expression Studies of Narrow-Leafed Lupin (Lupinus angustifolius L.)

PubMed Central

Erskine, William; Nelson, Matthew N.

2016-01-01

Quantitative Reverse Transcription PCR (qRT-PCR) is currently one of the most popular, high-throughput and sensitive technologies available for quantifying gene expression. Its accurate application depends heavily upon normalisation of gene-of-interest data with reference genes that are uniformly expressed under experimental conditions. The aim of this study was to provide the first validation of reference genes for Lupinus angustifolius (narrow-leafed lupin, a significant grain legume crop) using a selection of seven genes previously trialed as reference genes for the model legume, Medicago truncatula. In a preliminary evaluation, the seven candidate reference genes were assessed on the basis of primer specificity for their respective targeted region, PCR amplification efficiency, and ability to discriminate between cDNA and gDNA. Following this assessment, expression of the three most promising candidates [Ubiquitin C (UBC), Helicase (HEL), and Polypyrimidine tract-binding protein (PTB)] was evaluated using the NormFinder and RefFinder statistical algorithms in two narrow-leafed lupin lines, both with and without vernalisation treatment, and across seven organ types (cotyledons, stem, leaves, shoot apical meristem, flowers, pods and roots) encompassing three developmental stages. UBC was consistently identified as the most stable candidate and has sufficiently uniform expression that it may be used as a sole reference gene under the experimental conditions tested here. However, as organ type and developmental stage were associated with greater variability in relative expression, it is recommended using UBC and HEL as a pair to achieve optimal normalisation. These results highlight the importance of rigorously assessing candidate reference genes for each species across a diverse range of organs and developmental stages. With emerging technologies, such as RNAseq, and the completion of valuable transcriptome data sets, it is possible that other potentially more suitable reference genes will be identified for this species in future. PMID:26872362

A toy model that predicts the qualitative role of bar bend in a push jerk.

PubMed

Santos, Aaron; Meltzer, Norman E

2009-11-01

In this work, we describe a simple coarse-grained model of a barbell that can be used to determine the qualitative role of bar bend during a jerk. In simulations of this model, we observed a narrow time window during which the lifter can leverage the elasticity of the bar in order to lift the weight to a maximal height. This time window shifted to later times as the weight was increased. In addition, we found that the optimal time to initiate the drive was strongly correlated with the time at which the bar had reached a maximum upward velocity after recoiling. By isolating the effect of the bar, we obtained a generalized strategy for lifting heavy weight in the jerk.

Unravelling ancient microbial history with community proteogenomics and lipid geochemistry.

PubMed

Brocks, Jochen J; Banfield, Jillian

2009-08-01

Our window into the Earth's ancient microbial past is narrow and obscured by missing data. However, we can glean information about ancient microbial ecosystems using fossil lipids (biomarkers) that are extracted from billion-year-old sedimentary rocks. In this Opinion article, we describe how environmental genomics and related methodologies will give molecular fossil research a boost, by increasing our knowledge about how evolutionary innovations in microorganisms have changed the surface of planet Earth.

Management of Temporal Constraints for Factory Scheduling.

DTIC Science & Technology

1987-06-01

consistency of scheduling decisions were implemented in both the ISIS [Fox 84] and SOJA [LePape 85a] scheduling systems. More recent work with the...kinds of time propagation systems: the symbolic and the numeric ones. Symbolic systems combine relationships with a temporal logic a la Allen [Allen 81...maintains consistency by narrowing time windows associated with activities as decisions are made, and SOJA [LePape 85b] guarantees a schedule’s

Changes in mammary histology and transcriptome profiles by low-dose exposure to environmental phenols at critical windows of development.

PubMed

Gopalakrishnan, Kalpana; Teitelbaum, Susan L; Lambertini, Luca; Wetmur, James; Manservisi, Fabiana; Falcioni, Laura; Panzacchi, Simona; Belpoggi, Fiorella; Chen, Jia

2017-01-01

Exposure to environmental chemicals has been linked to altered mammary development and cancer risk at high doses using animal models. Effects at low doses comparable to human exposure remain poorly understood, especially during critical developmental windows. We investigated the effects of two environmental phenols commonly used in personal care products - methyl paraben (MPB) and triclosan (TCS) - on the histology and transcriptome of normal mammary glands at low doses mimicking human exposure during critical windows of development. Sprague-Dawley rats were exposed during perinatal, prepubertal and pubertal windows, as well as from birth to lactation. Low-dose exposure to MPB and TCS induced measurable changes in both mammary histology (by Masson's Trichrome Stain) and transcriptome (by microarrays) in a window-specific fashion. Puberty represented a window of heightened sensitivity to MPB, with increased glandular tissue and changes of expression in 295 genes with significant enrichment in functions such as DNA replication and cell cycle regulation. Long-term exposure to TCS from birth to lactation was associated with increased adipose and reduced glandular and secretory tissue, with expression alterations in 993 genes enriched in pathways such as cholesterol synthesis and adipogenesis. Finally, enrichment analyses revealed that genes modified by MPB and TCS were over-represented in human breast cancer gene signatures, suggesting possible links with breast carcinogenesis. These findings highlight the issues of critical windows of susceptibility that may confer heightened sensitivity to environmental insults and implicate the potential health effects of these ubiquitous environmental chemicals in breast cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Changes in Mammary Histology and Transcriptome Profiles by Low-Dose Exposure to Environmental Phenols at Critical Windows of Development1

PubMed Central

Gopalakrishnan, Kalpana; Teitelbaum, Susan L.; Lambertini, Luca; Wetmur, James; Manservisi, Fabiana; Falcioni, Laura; Panzacchi, Simona; Belpoggi, Fiorella; Chen, Jia

2016-01-01

Exposure to environmental chemicals has been linked to altered mammary development and cancer risk at high doses using animal models. Effects at low doses comparable to human exposure remain poorly understood, especially during critical developmental windows. We investigated the effects of two environmental phenols commonly used in personal care products – methyl paraben (MPB) and triclosan (TCS) – on the histology and transcriptome of normal mammary glands at low doses mimicking human exposure during critical windows of development. Sprague-Dawley rats were exposed during perinatal, prepubertal and pubertal windows, as well as from birth to lactation. Low-dose exposure to MPB and TCS induced measurable changes in both mammary histology (by Masson’s Trichrome Stain) and transcriptome (by microarrays) in a window-specific fashion. Puberty represented a window of heightened sensitivity to MPB, with increased glandular tissue and changes of expression in 295 genes with significant enrichment in functions such as DNA replication and cell cycle regulation. Long-term exposure to TCS from birth to lactation was associated with increased adipose and reduced glandular and secretory tissue, with expression alterations in 993 genes enriched in pathways such as cholesterol synthesis and adipogenesis. Finally, enrichment analyses revealed that genes modified by MPB and TCS were over-represented in human breast cancer gene signatures, suggesting possible links with breast carcinogenesis. These findings highlight the issues of critical windows of susceptibility that may confer heightened sensitivity to environmental insults and implicate the potential health effects of these ubiquitous environmental chemicals in breast cancer. PMID:27810681

Narrowing the Gap: Effects of Intervention on Developmental Trajectories in Autism

ERIC Educational Resources Information Center

Klintwall, Lars; Eldevik, Sigmund; Eikeseth, Svein

2015-01-01

Although still a matter of some debate, there is a growing body of research supporting Early and Intensive Behavioral Intervention as the intervention of choice for children with autism. Learning rate is an alternative to change in standard scores as an outcome measure in studies of early intervention. Learning rates can be displayed graphically…

Do convergent developmental mechanisms underlie convergent phenotypes?

NASA Technical Reports Server (NTRS)

Wray, Gregory A.

2002-01-01

Convergence is a pervasive evolutionary process, affecting many aspects of phenotype and even genotype. Relatively little is known about convergence in developmental processes, however, nor about the degree to which convergence in development underlies convergence in anatomy. A switch in the ecology of sea urchins from feeding to nonfeeding larvae illustrates how convergence in development can be associated with convergence in anatomy. Comparisons to more distantly related taxa, however, suggest that this association may be limited to relatively close phylogenetic comparisons. Similarities in gene expression during development provide another window into the association between convergence in developmental processes and convergence in anatomy. Several well-studied transcription factors exhibit likely cases of convergent gene expression in distantly related animal phyla. Convergence in regulatory gene expression domains is probably more common than generally acknowledged, and can arise for several different reasons. Copyright 2002 S. Karger AG, Basel.

Critical period plasticity is disrupted in the barrel cortex of Fmr1 knockout mice

PubMed Central

Harlow, Emily G.; Till, Sally M.; Russell, Theron A.; Wijetunge, Lasani S.; Kind, Peter; Contractor, Anis

2010-01-01

Summary Alterations in sensory processing constitute prominent symptoms of Fragile X syndrome; however, little is known about how disrupted synaptic and circuit development in sensory cortex contributes to these deficits. To investigate how the loss of fragile X mental retardation protein (FMRP) impacts the development of cortical synapses, we examined excitatory thalamocortical synapses in somatosensory cortex during the perinatal critical period in Fmr1 knockout mice. FMRP ablation resulted in dysregulation of glutamatergic signaling maturation. The fraction of silent synapses persisting to later developmental times was increased, there was a temporal delay in the window for synaptic plasticity, while other forms of developmental plasticity were not altered in Fmr1 knockout mice. Our results indicate that FMRP is required for the normal developmental progression of synaptic maturation, and loss of this important RNA binding protein impacts the timing of the critical period for layer IV synaptic plasticity. PMID:20159451

An aqueous electrolyte of the widest potential window and its superior capability for capacitors.

PubMed

Tomiyasu, Hiroshi; Shikata, Hirokazu; Takao, Koichiro; Asanuma, Noriko; Taruta, Seiichi; Park, Yoon-Yul

2017-03-21

A saturated aqueous solution of sodium perchlorate (SSPAS) was found to be electrochemically superior, because the potential window is remarkably wide to be approximately 3.2 V in terms of a cyclic voltammetry. Such a wide potential window has never been reported in any aqueous solutions, and this finding would be of historical significance for aqueous electrolyte to overcome its weak point that the potential window is narrow. In proof of this fact, the capability of SSPAS was examined for the electrolyte of capacitors. Galvanostatic charge-discharge measurements showed that a graphite-based capacitor containing SSPAS as an electrolyte was stable within 5% deviation for the 10,000 times repetition at the operating voltage of 3.2 V without generating any gas. The SSPAS worked also as a functional electrolyte in the presence of an activated carbon and metal oxides in order to increase an energy density. Indeed, in an asymmetric capacitor containing MnO 2 and Fe 3 O 4 mixtures in the positive and negative electrodes, respectively, the energy density enlarged to be 36.3 Whkg -1 , which belongs to the largest value in capacitors. Similar electrochemical behaviour was also confirmed in saturated aqueous solutions of other alkali and alkaline earth metal perchlorate salts.

Wide electrochemical window of supercapacitors from coffee bean-derived phosphorus-rich carbons.

PubMed

Huang, Congcong; Sun, Ting; Hulicova-Jurcakova, Denisa

2013-12-01

Phosphorus-rich carbons (PCs) were prepared by phosphoric acid activation of waste coffee grounds in different impregnation ratios. PCs were characterized by nitrogen and carbon dioxide adsorption and X-ray photoelectron spectroscopy. The results indicate that the activation step not only creates a porous structure, but also introduces various phosphorus and oxygen functional groups to the surface of carbons. As evidenced by cyclic voltammetry, galvanostatic charge/discharge, and wide potential window tests, a supercapacitor constructed from PC-2 (impregnation ratio of 2), with the highest phosphorus content, can operate very stably in 1 M H2 SO4 at 1.5 V with only 18 % degradation after 10 000 cycles at a current density of 5 A g(-1) . Due to the wide electrochemical window, a supercapacitor assembled with PC-2 has a high energy density of 15 Wh kg(-1) at a power density of 75 W kg(-1) . The possibility of widening the potential window above the theoretical potential for the decomposition of water is attributed to reversible electrochemical hydrogen storage in narrow micropores and the positive effect of phosphorus-rich functional groups, particularly the polyphosphates on the carbon surface. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An aqueous electrolyte of the widest potential window and its superior capability for capacitors

PubMed Central

Tomiyasu, Hiroshi; Shikata, Hirokazu; Takao, Koichiro; Asanuma, Noriko; Taruta, Seiichi; Park, Yoon-Yul

2017-01-01

A saturated aqueous solution of sodium perchlorate (SSPAS) was found to be electrochemically superior, because the potential window is remarkably wide to be approximately 3.2 V in terms of a cyclic voltammetry. Such a wide potential window has never been reported in any aqueous solutions, and this finding would be of historical significance for aqueous electrolyte to overcome its weak point that the potential window is narrow. In proof of this fact, the capability of SSPAS was examined for the electrolyte of capacitors. Galvanostatic charge-discharge measurements showed that a graphite-based capacitor containing SSPAS as an electrolyte was stable within 5% deviation for the 10,000 times repetition at the operating voltage of 3.2 V without generating any gas. The SSPAS worked also as a functional electrolyte in the presence of an activated carbon and metal oxides in order to increase an energy density. Indeed, in an asymmetric capacitor containing MnO2 and Fe3O4 mixtures in the positive and negative electrodes, respectively, the energy density enlarged to be 36.3 Whkg−1, which belongs to the largest value in capacitors. Similar electrochemical behaviour was also confirmed in saturated aqueous solutions of other alkali and alkaline earth metal perchlorate salts. PMID:28322349

Compound windows of the Hénon-map

NASA Astrophysics Data System (ADS)

Lorenz, Edward N.

2008-08-01

For the two-parameter second-order Hénon map, the shapes and locations of the periodic windows-continua of parameter values for which solutions x0,x1,… can be stably periodic, embedded in larger regions where chaotic solutions or solutions of other periods prevail-are found by a random searching procedure and displayed graphically. Many windows have a typical shape, consisting of a central “body” from which four narrow “antennae” extend. Such windows, to be called compound windows, are often arranged in bands, to be called window streets, that are made up largely of small detected but poorly resolved compound windows. For each fundamental subwindow-the portion of a window where a fundamental period prevails-a stability measure U is introduced; where the solution is stable, |U|<1. Curves of constant U are found by numerical integration. Along one line in parameter space the Hénon-map reduces to the one-parameter first-order logistic map, and two antennae from each compound window intersect this line. The curves where U=1 and U=-1 that bound either antenna are close together within these intersections, but, as either curve with U=-1 leaves the line, it diverges from the curve where U=1, crosses the other curve where U=-1, and nears the other curve where U=1, forming another antenna. The region bounded by the numerically determined curves coincides with the subwindow as found by random searching. A fourth-degree equation for an idealized curve of constant U is established. Points in parameter space producing periodic solutions where x0=xm=0, for given values of m, are found to lie on Cantor sets of curves that closely fit the window streets. Points producing solutions where x0=xm=0 and satisfying a third condition, approximating the condition that xn be bounded as n→-∞, lie on curves, to be called street curves of order m, that approximate individual members of the Cantor set and individual window streets. Compound windows of period m+m‧ tend to occur near the intersections of street curves of orders m and m‧. Some exceptions to what appear to be fairly general results are noted. The exceptions render it difficult to establish general theorems.

Effect of magnetic field on the optical properties of an inhomogeneously broadened multilevel Λ-system in Rb vapor

NASA Astrophysics Data System (ADS)

Kaur, Paramjit; Wasan, Ajay

2017-03-01

We present a theoretical model, using density matrix approach, to study the effect of external longitudinal and transverse magnetic fields on the optical properties of an inhomogeneously broadened multilevel Λ-system using the D2 line in 85Rb and 87Rb atoms. The presence of closely spaced multiple excited states causes asymmetry in the absorption and dispersion profiles. We observe a wide EIT window with a positive slope at the line center for a stationary atom. While for a moving atom, the linewidth of EIT window reduces and positive dispersion becomes steeper. When magnetic field is applied, our calculations show multiple EIT subwindows that are significantly narrower and shallow than single EIT window. The number of EIT subwindows depend on the orientation of the magnetic field. We also obtain multiple positive dispersive regions for subluminal propagation in the medium. The anomalous dispersion exists in between two subwindows showing the superluminal light propagation. Our theoretical analysis explain the experiments performed by Wei et al. [Phys. Rev. A 72, 023806 (2005)] and Iftiquar et al. [Phys. Rev. A 79, 013808 (2009)].

Integration of ground-penetrating radar, ultrasonic tests and infrared thermography for the analysis of a precious medieval rose window

NASA Astrophysics Data System (ADS)

Nuzzo, L.; Calia, A.; Liberatore, D.; Masini, N.; Rizzo, E.

2010-04-01

The integration of high-resolution, non-invasive geophysical techniques (such as ground-penetrating radar or GPR) with emerging sensing techniques (acoustics, thermography) can complement limited destructive tests to provide a suitable methodology for a multi-scale assessment of the state of preservation, material and construction components of monuments. This paper presents the results of the application of GPR, infrared thermography (IRT) and ultrasonic tests to the 13th century rose window of Troia Cathedral (Apulia, Italy), affected by widespread decay and instability problems caused by the 1731 earthquake and reactivated by recent seismic activity. This integrated approach provided a wide amount of complementary information at different scales, ranging from the sub-centimetre size of the metallic joints between the various architectural elements, narrow fractures and thin mortar fillings, up to the sub-metre scale of the internal masonry structure of the circular ashlar curb linking the rose window to the façade, which was essential to understand the original building technique and to design an effective restoration strategy.

Erk-Creb pathway suppresses glutathione-S-transferase pi expression under basal and oxidative stress conditions in zebrafish embryos.

PubMed

Hrubik, Jelena; Glisic, Branka; Fa, Svetlana; Pogrmic-Majkic, Kristina; Andric, Nebojsa

2016-01-05

Transcriptional activation of phase II enzymes including glutathione-S-transferase pi class (Gst Pi) is important for redox regulation and defense from xenobiotics. The role of extracellular signal-regulated kinase (Erk) and protein kinase B (Akt) in regulation of Gst Pi expression has been described using adult mammalian cells. Whether these signaling pathways contribute to Gst Pi expression during embryogenesis is unknown. Using zebrafish embryo model, we provide novel evidence that Erk signaling acts as a specific suppressor of gstp1-2 mRNA during early embryogenesis. Addition of Erk inhibitor U0126 enhanced gstp1-2 mRNA expression during transition from blastula to the segmentation stage and from pharyngula until the hatching stage. Basal Erk activity did not affect gstp1-2 expression in tert-butylhydroquinone-exposed embryos. Addition of phorbol 12-myristate 13-acetate increased Erk activity leading to suppression of gstp1-2 mRNA. Activation of cAMP/Creb pathway by forskolin prevented gstp1-2 expression, whereas U0126 suppressed Creb phosphorylation, thus setting up Creb as a proximal transmitter of Erk inhibitory effect. Collectively, these findings suggest that Erk-Creb pathway exerts suppressive effect on gstp1-2 mRNA in a narrow developmental window. This study also provides a novel link between Erk and gstp1-2 expression, setting apart a possible differential regulation of gstp1-2 in adult and embryonic cells. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prior, P; Timmins, R; Wells, R G

Dual isotope SPECT allows simultaneous measurement of two different tracers in vivo. With In111 (emission energies of 171keV and 245keV) and Tc99m (140keV), quantification of Tc99m is degraded by cross talk from the In111 photons that scatter and are detected at an energy corresponding to Tc99m. TEW uses counts recorded in two narrow windows surrounding the Tc99m primary window to estimate scatter. Iterative TEW corrects for the bias introduced into the TEW estimate resulting from un-scattered counts detected in the scatter windows. The contamination in the scatter windows is iteratively estimated and subtracted as a fraction of the scatter-corrected primarymore » window counts. The iterative TEW approach was validated with a small-animal SPECT/CT camera using a 2.5mL plastic container holding thoroughly mixed Tc99m/In111 activity fractions of 0.15, 0.28, 0.52, 0.99, 2.47 and 6.90. Dose calibrator measurements were the gold standard. Uncorrected for scatter, the Tc99m activity was over-estimated by as much as 80%. Unmodified TEW underestimated the Tc99m activity by 13%. With iterative TEW corrections applied in projection space, the Tc99m activity was estimated within 5% of truth across all activity fractions above 0.15. This is an improvement over the non-iterative TEW, which could not sufficiently correct for scatter in the 0.15 and 0.28 phantoms.« less

DPOAEs in infants developmentally exposed to PCBs show two differently time spaced exposure sensitive windows.

PubMed

Koštiaková, Vladimíra; Moleti, Arturo; Wimmerová, Soňa; Jusko, Todd A; Palkovičová Murínová, Ľubica; Sisto, Renata; Richterová, Denisa; Kováč, Ján; Čonka, Kamil; Patayová, Henrieta; Tihányi, Juraj; Trnovec, Tomáš

2016-10-01

The study aim was to identify the timing of sensitive windows for ototoxicity related to perinatal exposure to PCBs. A total of 351 and 214 children from a birth cohort in eastern Slovakia underwent otoacoustic testing at 45 and 72 months, respectively, and distortion product otoacoustic emissions (DPOAEs) at 11 frequencies were recorded. Cord and child 6-, 16-, 45-, and 72- month blood samples were analyzed for PCB 153 concentration. The PCB 153 concentration-time profiles were approximated with a system model to calculate area under the PCB*time curves (AUCs) for specific time intervals (3 and 6 months for 45 and 72 months data, respectively). DPOAE amplitudes were correlated (Spearman) with cord serum PCB and AUCs, markers of prenatal and postnatal exposure, respectively. Two exposure critical windows were identified in infants, the first related to prenatal and early postnatal and the second to postnatal exposure to PCBs. Our data have shown tonotopicity, sexual dimorphism, and asymmetry in ototoxicity of PCBs. Copyright © 2016. Published by Elsevier Ltd.

ARC-1985-AC85-0199-5

NASA Image and Video Library

1985-03-02

Artist: Gebing Artist's conception of a newborne star, still hidden in visible light by the dust clouds within which it formed, shows matter in orbit around the rotating star. Such leftover debris may eventually form comets, planets, satellites, and asteroids. Material squeezed out by the formation process is thought to be ejected along the star's rotation axis in relatively narrow, high-velocity streams of matter. (ref: SIRTF borchure 'A Window on Cosmic Birth 1987) -- Milky Way with Black hole

Disorder-to-order transitions induced by alkyne/azide click chemistry in diblock copolymer thin films.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, X.; Gu, W.; Chen, W.

2012-01-01

We investigated thin film morphologies of binary blends of alkyne-functionalized diblock copolymer poly(ethylene oxide)-block-poly(n-butyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) and Rhodamine B azide, where the thermal alkyne/azide click reaction between the two components induced a disorder-to-order transition (DOT) of the copolymer. By controlling the composition of the neat copolymers and the mole ratio between the alkyne and azide groups, different microphase separated morphologies were achieved. At higher azide loading ratios, a perpendicular orientation of the microdomains was observed with wide accessible film thickness window. As less azide was incorporated, the microdomains have a stronger tendency to be parallel to the substrate, andmore » the film thickness window for perpendicular orientation also became narrower.« less

Tunable Narrow Band Emissions from Dye-Sensitized Core/Shell/Shell Nanocrystals in the Second Near-Infrared Biological Window

PubMed Central

Shao, Wei; Chen, Guanying; Kuzmin, Andrey; Kutscher, Hilliard L.; Pliss, Artem; Ohulchanskyy, Tymish Y.; Prasad, Paras N.

2017-01-01

We introduce a hybrid organic–inorganic system consisting of epitaxial NaYF4:Yb3+/X3+@NaYbF4@NaYF4:Nd3+ (X = null, Er, Ho, Tm, or Pr) core/shell/shell (CSS) nanocrystal with organic dye, indocyanine green (ICG) on the nanocrystal surface. This system is able to produce a set of narrow band emissions with a large Stokes-shift (>200 nm) in the second biological window of optical transparency (NIR-II, 1000–1700 nm), by directional energy transfer from light-harvesting surface ICG, via lanthanide ions in the shells, to the emitter X3+ in the core. Surface ICG not only increases the NIR-II emission intensity of inorganic CSS nanocrystals by ~4-fold but also provides a broadly excitable spectral range (700–860 nm) that facilitates their use in bioapplications. We show that the NIR-II emission from ICG-sensitized Er3+-doped CSS nanocrystals allows clear observation of a sharp image through 9 mm thick chicken breast tissue, and emission signal detection through 22 mm thick tissue yielding a better imaging profile than from typically used Yb/Tm-codoped upconverting nanocrystals imaged in the NIR-I region (700–950 nm). Our result on in vivo imaging suggests that these ICG-sensitized CSS nanocrystals are suitable for deep optical imaging in the NIR-II region. PMID:27935695

A true minimally invasive approach for cochlear implantation: high accuracy in cranial base navigation through flat-panel-based volume computed tomography.

PubMed

Majdani, Omid; Bartling, Soenke H; Leinung, Martin; Stöver, Timo; Lenarz, Minoo; Dullin, Christian; Lenarz, Thomas

2008-02-01

High-precision intraoperative navigation using high-resolution flat-panel volume computed tomography makes feasible the possibility of minimally invasive cochlear implant surgery, including cochleostomy. Conventional cochlear implant surgery is typically performed via mastoidectomy with facial recess to identify and avoid damage to vital anatomic landmarks. To accomplish this procedure via a minimally invasive approach--without performing mastoidectomy--in a precise fashion, image-guided technology is necessary. With such an approach, surgical time and expertise may be reduced, and hearing preservation may be improved. Flat-panel volume computed tomography was used to scan 4 human temporal bones. A drilling channel was planned preoperatively from the mastoid surface to the round window niche, providing a margin of safety to all functional important structures (e.g., facial nerve, chorda tympani, incus). Postoperatively, computed tomographic imaging and conventional surgical exploration of the drilled route to the cochlea were performed. All 4 specimens showed a cochleostomy located at the scala tympani anterior inferior to the round window. The chorda tympani was damaged in 1 specimen--this was preoperatively planned as a narrow facial recess was encountered. Using flat-panel volume computed tomography for image-guided surgical navigation, we were able to perform minimally invasive cochlear implant surgery defined as a narrow, single-channel mastoidotomy with cochleostomy. Although this finding is preliminary, it is technologically achievable.

Atomistic simulations of CO2 and N2 within cage-type silica zeolites.

PubMed

Madison, Lindsey; Heitzer, Henry; Russell, Colin; Kohen, Daniela

2011-03-01

The behavior of CO(2) and N(2), both as single components and as binary mixtures, in two cage-type silica zeolites was studied using atomistic simulations. The zeolites considered, ITQ-3 and paradigm cage-type zeolite ZK4 (the all-silica analog of LTA), were chosen so that the principles illustrated can be generalized to other adsorbent/adsorbate systems with similar topology and types of interactions. N(2) was chosen both because of the potential uses of N(2)/CO(2) separations and because it differs from CO(2) most significantly in the magnitude of its Coulombic interactions with zeolites. Despite similarities between N(2) and CO(2) diffusion in other materials, we show here that the diffusion of CO(2) within cage-type zeolites is dominated by an energy barrier to diffusion located at the entrance to the narrow channels connecting larger cages. This barrier originates in Coulombic interactions between zeolites and CO(2)'s quadrupole and results in well-defined orientations for the diffusing molecules. Furthermore, CO(2)'s favorable electrostatic interactions with the zeolite framework result in preferential binding in the windows between cages. N(2)'s behavior, in contrast, is more consistent with that of molecules previously studied. Our analysis suggests that CO(2)'s behavior might be common for adsorbates with quadrupoles that interact strongly with a material that has narrow windows between cages.

Fundamental resource dis/advantages, youth health and adult educational outcomes.

PubMed

Elman, Cheryl; Wray, Linda A; Xi, Juan

2014-01-01

Recent studies find lasting effects of poor youth health on educational attainment but use young samples and narrow life course windows of observation to explore outcomes. We apply a life course framework to three sets of Health and Retirement Study birth cohorts to examine early health status effects on education and skills attainment measured late in life. The older cohorts that we study were the earliest recipients of U.S. policies promoting continuing education through the GI Bill, community college expansions and new credentials such as the GED. We examine a wide range of outcomes but focus on GEDs, postsecondary school entry and adult human capital as job-related training. We find that older U.S. cohorts had considerable exposure to these forms of attainment and that the effects of youth health on them vary by outcome: health selection and ascription group effects are weak or fade, respectively, in outcomes associated with delayed or adult attainment. However, poorer health and social disadvantage in youth and barriers associated with ascription carry forward to limit attainment of key credentials such as diplomas and college degrees. We find that the human capital - health gradient is dynamic and that narrow windows of observation in existing studies miss much of it. National context also matters for studying health-education linkages over the life course. Copyright © 2013 Elsevier Inc. All rights reserved.

Biochemical basis for pharmacological intervention as a reprogramming strategy against hypertension and kidney disease of developmental origin.

PubMed

Tain, You-Lin; Chan, Samuel H H; Chan, Julie Y H

2018-07-01

The concept of "developmental origins of health and disease" (DOHaD) stipulates that both hypertension and kidney disease may take origin from early-life insults. The DOHaD concept also offers reprogramming strategies aiming at shifting therapeutic interventions from adulthood to early life, even before clinical symptoms are evident. Based on those two concepts, this review will present the evidence for the existence of, and the programming mechanisms in, kidney developmental programming that may lead to hypertension and kidney disease. This will be followed by potential pharmacological interventions that may serve as a reprogramming strategy to counter the rising epidemic of hypertension and kidney disease. We point out that before patients could benefit from this strategy, the most pressing issue is for the growing body of evidence from animal studies in support of pharmacological intervention as a reprogramming strategy to long-term protect against hypertension and kidney disease of developmental origins to be validated clinically and the critical window, drug dose, dosing regimen, and therapeutic duration identified. Copyright © 2018 Elsevier Inc. All rights reserved.

The study on achievement of motor milestones and associated factors among children in rural North India

PubMed Central

Gupta, Arti; Kalaivani, Mani; Gupta, Sanjeev Kumar; Rai, Sanjay K.; Nongkynrih, Baridalyne

2016-01-01

Background: Nearly 14% of children worldwide do not reach their developmental potential in early childhood. The early identification of delays in achieving milestones is critical. The World Health Organization (WHO) has developed normal age ranges for the achievement of motor milestones by healthy children. This study aimed to assess the gross motor developmental achievements and associated factors among children in rural India. Materials and Methods: A cross-sectional study was conducted with rural children in North India. A pretested questionnaire was used to collect the data. The median age at the time of the highest observed milestone was calculated and compared with the WHO windows of achievement. Results: Overall, 221 children aged 4–18 months were included in the study. The median age of motor development exhibited a 0.1–2.1-month delay compared to the WHO median age of motor milestone achievement. The prevalence of the gross motor milestone achievements for each of the six milestones ranged from 91.6% to 98.4%. Developmental delay was observed in 6.3% of the children. After adjusting for different variables, children with birth order of second or more were found to be significantly associated with the timely achievement of gross motor milestones. Conclusion: The apparently healthy children of the rural area of Haryana achieved gross motor milestones with some delay with respect to the WHO windows of achievement. Although the median value of this delay was low, awareness campaigns should be implemented to promote timely identification of children with development delays. PMID:27843845

Neuropsychological basic deficits in preschoolers at risk for ADHD: a meta-analysis.

PubMed

Pauli-Pott, Ursula; Becker, Katja

2011-06-01

Widely accepted neuropsychological theories on attention deficit hyperactivity disorder (ADHD) assume that the complex symptoms of the disease arise from developmentally preceding neuropsychological basic deficits. These deficits in executive functions and delay aversion are presumed to emerge in the preschool period. The corresponding normative developmental processes include phases of relative stability and rapid change. These non-linear developmental processes might have implications for concurrent and predictive associations between basic deficits and ADHD symptoms. To derive a description of the nature and strength of these associations, a meta-analysis was conducted. It is assumed that weighted mean effect sizes differ between basic deficits and depend on age. The meta-analysis included 25 articles (n=3005 children) in which associations between assessments of basic deficits (i.e. response inhibition, interference control, delay aversion, working memory, flexibility, and vigilance/arousal) in the preschool period and concurrent or subsequent ADHD symptoms or diagnosis of ADHD had been analyzed. For response inhibition and delay aversion, mean effect sizes were of medium to large magnitude while the mean effect size for working memory was small. Meta-regression analyses revealed that effect sizes of delay aversion tasks significantly decreased with increasing age while effect sizes of interference control tasks and Continuous Performance Tests (CPTs) significantly increased. Depending on the normative maturational course of each skill, time windows might exist that allow for a more or less valid assessment of a specific deficit. In future research these time windows might help to describe early developing forms of ADHD and to identify children at risk. Copyright © 2011 Elsevier Ltd. All rights reserved.

Age Differences in Prenatal Testosterone's Protective Effects on Disordered Eating Symptoms: Developmental Windows of Expression?

PubMed Central

Culbert, Kristen M.; Breedlove, S. Marc; Sisk, Cheryl L.; Keel, Pamela K.; Neale, Michael C.; Boker, Steven M.; Burt, S. Alexandra; Klump, Kelly L.

2015-01-01

Prenatal testosterone exposure may be protective against disordered eating. However, prior studies have produced mixed results. Developmental differences in prenatal testosterone's protective effects on disordered eating may explain these discrepancies. Indeed, studies have differed in the age of participants assessed, with data supporting prenatal testosterone effects on disordered eating in early adolescent and young adult samples but not in late adolescence. The present series of studies are the first to investigate age differences in prenatal testosterone's protective effects on disordered eating. Two indirect markers of higher prenatal testosterone were examined: 1) lower finger-length ratios [index (2D)/ring (4D) finger] (Study 1), and 2) lower disordered eating in females from opposite-sex twin pairs (who are thought to be exposed to higher prenatal testosterone from their male co-twin) relative to female controls (Study 2). Participants were twins from the Michigan State University Twin Registry (Study 1: n = 409; Study 2: n = 1,538) in early adolescence, late adolescence, or young adulthood. Disordered eating was assessed with well-validated questionnaires. Finger-length ratios were measured from hand scans, using electronic computer calipers. Findings were consistent across both studies. Higher prenatal testosterone (lower 2D:4D; females from opposite-sex twin pairs vs. controls) predicted lower disordered eating in early adolescence and young adulthood only. Prenatal testosterone-disordered eating associations were not observed during late adolescence. Results point to the possibility of developmental windows of expression for prenatal testosterone's protective effects on disordered eating and suggest that prior discrepant results may reflect age differences across samples. PMID:25621790

A Teacher's Window into the Child's Mind and Papers from the Institute for Neuro-Physiological Psychology. A Non-Invasive Approach to Solving Learning and Behavior Problems.

ERIC Educational Resources Information Center

Goddard, Sally

This book describes a neuro-developmental approach to learning difficulty assessment and remediation through assessment of a student's reception of information through the sensory channels, processing of sensory information in the brain, and repertoire of responses for expression. Chapter 1, "Reflexes: Their Impact on Success or Failure in…

Children Who Desperately Want To Read, But Are Not Working at Grade Level: Use Movement Patterns as "Windows" To Discover Why.

ERIC Educational Resources Information Center

Corso, Marjorie

A qualitative longitudinal study, first of four parts, compared developmental movement levels and academic learning levels in young children. Subjects were 28 children of various ages who were not working up to grade level but who did not qualify for learning disability services. Parents completed a detailed demographic survey and a neurological…

A Developmental Shift from Similar to Language-Specific Strategies in Verb Acquisition: A Comparison of English, Spanish, and Japanese

ERIC Educational Resources Information Center

Maguire, Mandy J.; Hirsh-Pasek, Kathy; Golinkoff, Roberta Michnick; Imai, Mutsumi; Haryu, Etsuko; Vanegas, Sandra; Okada, Hiroyuki; Pulverman, Rachel; Sanchez-Davis, Brenda

2010-01-01

The world's languages draw on a common set of event components for their verb systems. Yet, these components are differentially distributed across languages. At what age do children begin to use language-specific patterns to narrow possible verb meanings? English-, Japanese-, and Spanish-speaking adults, toddlers, and preschoolers were shown…

Two-step phase-shifting SPIDER

NASA Astrophysics Data System (ADS)

Zheng, Shuiqin; Cai, Yi; Pan, Xinjian; Zeng, Xuanke; Li, Jingzhen; Li, Ying; Zhu, Tianlong; Lin, Qinggang; Xu, Shixiang

2016-09-01

Comprehensive characterization of ultrafast optical field is critical for ultrashort pulse generation and its application. This paper combines two-step phase-shifting (TSPS) into the spectral phase interferometry for direct electric-field reconstruction (SPIDER) to improve the reconstruction of ultrafast optical-fields. This novel SPIDER can remove experimentally the dc portion occurring in traditional SPIDER method by recording two spectral interferograms with π phase-shifting. As a result, the reconstructed results are much less disturbed by the time delay between the test pulse replicas and the temporal widths of the filter window, thus more reliable. What is more, this SPIDER can work efficiently even the time delay is so small or the measured bandwidth is so narrow that strong overlap happens between the dc and ac portions, which allows it to be able to characterize the test pulses with complicated temporal/spectral structures or narrow bandwidths.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Fei; Maier, T. A.; Scarola, V. W.

The extended Bose-Hubbard model captures the essential properties of a wide variety of physical systems including ultracold atoms and molecules in optical lattices, Josephson junction arrays, and certain narrow band superconductors. It exhibits a rich phase diagram including a supersolid phase where a lattice solid coexists with a superfluid. We use quantum Monte Carlo to study the supersolid part of the phase diagram of the extended Bose-Hubbard model on the simple cubic lattice. We add disorder to the extended Bose-Hubbard model and find that the maximum critical temperature for the supersolid phase tends to be suppressed by disorder. But wemore » also find a narrow parameter window in which the supersolid critical temperature is enhanced by disorder. Our results show that supersolids survive a moderate amount of spatial disorder and thermal fluctuations in the simple cubic lattice.« less

Lagged kernel machine regression for identifying time windows of susceptibility to exposures of complex mixtures.

PubMed

Liu, Shelley H; Bobb, Jennifer F; Lee, Kyu Ha; Gennings, Chris; Claus Henn, Birgit; Bellinger, David; Austin, Christine; Schnaas, Lourdes; Tellez-Rojo, Martha M; Hu, Howard; Wright, Robert O; Arora, Manish; Coull, Brent A

2018-07-01

The impact of neurotoxic chemical mixtures on children's health is a critical public health concern. It is well known that during early life, toxic exposures may impact cognitive function during critical time intervals of increased vulnerability, known as windows of susceptibility. Knowledge on time windows of susceptibility can help inform treatment and prevention strategies, as chemical mixtures may affect a developmental process that is operating at a specific life phase. There are several statistical challenges in estimating the health effects of time-varying exposures to multi-pollutant mixtures, such as: multi-collinearity among the exposures both within time points and across time points, and complex exposure-response relationships. To address these concerns, we develop a flexible statistical method, called lagged kernel machine regression (LKMR). LKMR identifies critical exposure windows of chemical mixtures, and accounts for complex non-linear and non-additive effects of the mixture at any given exposure window. Specifically, LKMR estimates how the effects of a mixture of exposures change with the exposure time window using a Bayesian formulation of a grouped, fused lasso penalty within a kernel machine regression (KMR) framework. A simulation study demonstrates the performance of LKMR under realistic exposure-response scenarios, and demonstrates large gains over approaches that consider each time window separately, particularly when serial correlation among the time-varying exposures is high. Furthermore, LKMR demonstrates gains over another approach that inputs all time-specific chemical concentrations together into a single KMR. We apply LKMR to estimate associations between neurodevelopment and metal mixtures in Early Life Exposures in Mexico and Neurotoxicology, a prospective cohort study of child health in Mexico City.

Superior Volumetic Modulated Arc Therapy Planning Solution for Prostate Patients

DTIC Science & Technology

2014-07-01

narrow; it was selected to enhance the visibility of the small low-contrast tumors. The width of this window corresponds to about 13.5 Hounsfield units ...1R01EB013118-01 from the National Institute of Health. In order to obtain relative stopping power (RSP), Hounsfield units (i.e. units of x-ray...attenuation used in x-ray CT) are trans- formed using a calibration curve. However, there is no unique relationship between Hounsfield units and RSP, especially

Latitudinal variation in photoperiodic response of the three-spined stickleback Gasterosteus aculeatus in western North America

PubMed Central

Yeates-Burghart, Q. S.; O’Brien, C.; Cresko, W. A.; Holzapfel, C. M.; Bradshaw, W. E.

2014-01-01

Reproductive maturation in both male and female three-spined stickleback Gasterosteus aculeatus was strongly photoperiodic in a northern population (Alaska, 61° N) but not in a southern population (Oregon, 43° N) from western North America. Increasing reliance on photoperiod with increasing latitude is a general phenomenon among vertebrates, and is probably due to the anticipation of a narrower window of opportunity for reproduction and development at higher latitudes. PMID:20738673

Is There a Critical Period for the Developmental Neurotoxicity of Low-Level Tobacco Smoke Exposure?

PubMed

Slotkin, Theodore A; Stadler, Ashley; Skavicus, Samantha; Card, Jennifer; Ruff, Jonathan; Levin, Edward D; Seidler, Frederic J

2017-01-01

Secondhand tobacco smoke exposure in pregnancy increases the risk of neurodevelopmental disorders. We evaluated in rats whether there is a critical period during which tobacco smoke extract (TSE) affects the development of acetylcholine and serotonin systems, prominent targets for adverse effects of nicotine and tobacco smoke. We simulated secondhand smoke exposure by administering TSE so as to produce nicotine concentrations one-tenth those in active smoking, with 3 distinct, 10-day windows: premating, early gestation or late gestation. We conducted longitudinal evaluations in multiple brain regions, starting in early adolescence (postnatal day 30) and continued to full adulthood (day 150). TSE exposure in any of the 3 windows impaired presynaptic cholinergic activity, exacerbated by a decrement in nicotinic cholinergic receptor concentrations. Although the adverse effects were seen for all 3 treatment windows, there was a distinct progression, with lowest sensitivity for premating exposure and higher sensitivity for gestational exposures. Serotonin receptors were also reduced by TSE exposure with the same profile: little effect with premating exposure, intermediate effect with early gestational exposure and large effect with late gestational exposure. As serotonergic circuits can offset the neurobehavioral impact of cholinergic deficits, these receptor changes were maladaptive. Thus, there is no single 'critical period' for effects of low-level tobacco smoke but there is differential sensitivity dependent upon the developmental stage at the time of exposure. Our findings reinforce the need to avoid secondhand smoke exposure not only during pregnancy, but also in the period prior to conception, or generally for women of childbearing age. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Children Who Desperately Want To Read, But Are Not Working at Grade Level: Use Movement Patterns As "Windows" To Discover Why. Part II: The Transverse Midline.

ERIC Educational Resources Information Center

Corso, Marjorie

This paper discusses a multi-part longitudinal study which compared the developmental movement levels and the academic learning level in young children, noting that the relationship between movement education and academic education is based on the assumption that both realms of learning are dependent on the adequate development of the brain. The…

Developmental changes in organization of structural brain networks.

PubMed

Khundrakpam, Budhachandra S; Reid, Andrew; Brauer, Jens; Carbonell, Felix; Lewis, John; Ameis, Stephanie; Karama, Sherif; Lee, Junki; Chen, Zhang; Das, Samir; Evans, Alan C

2013-09-01

Recent findings from developmental neuroimaging studies suggest that the enhancement of cognitive processes during development may be the result of a fine-tuning of the structural and functional organization of brain with maturation. However, the details regarding the developmental trajectory of large-scale structural brain networks are not yet understood. Here, we used graph theory to examine developmental changes in the organization of structural brain networks in 203 normally growing children and adolescents. Structural brain networks were constructed using interregional correlations in cortical thickness for 4 age groups (early childhood: 4.8-8.4 year; late childhood: 8.5-11.3 year; early adolescence: 11.4-14.7 year; late adolescence: 14.8-18.3 year). Late childhood showed prominent changes in topological properties, specifically a significant reduction in local efficiency, modularity, and increased global efficiency, suggesting a shift of topological organization toward a more random configuration. An increase in number and span of distribution of connector hubs was found in this age group. Finally, inter-regional connectivity analysis and graph-theoretic measures indicated early maturation of primary sensorimotor regions and protracted development of higher order association and paralimbic regions. Our finding reveals a time window of plasticity occurring during late childhood which may accommodate crucial changes during puberty and the new developmental tasks that an adolescent faces.

Concurrent validity of the Microsoft Kinect for Windows v2 for measuring spatiotemporal gait parameters.

PubMed

Dolatabadi, Elham; Taati, Babak; Mihailidis, Alex

2016-09-01

This paper presents a study to evaluate the concurrent validity of the Microsoft Kinect for Windows v2 for measuring the spatiotemporal parameters of gait. Twenty healthy adults performed several sequences of walks across a GAITRite mat under three different conditions: usual pace, fast pace, and dual task. Each walking sequence was simultaneously captured with two Kinect for Windows v2 and the GAITRite system. An automated algorithm was employed to extract various spatiotemporal features including stance time, step length, step time and gait velocity from the recorded Kinect v2 sequences. Accuracy in terms of reliability, concurrent validity and limits of agreement was examined for each gait feature under different walking conditions. The 95% Bland-Altman limits of agreement were narrow enough for the Kinect v2 to be a valid tool for measuring all reported spatiotemporal parameters of gait in all three conditions. An excellent intraclass correlation coefficient (ICC2, 1) ranging from 0.9 to 0.98 was observed for all gait measures across different walking conditions. The inter trial reliability of all gait parameters were shown to be strong for all walking types (ICC3, 1 > 0.73). The results of this study suggest that the Kinect for Windows v2 has the capacity to measure selected spatiotemporal gait parameters for healthy adults. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

A narrow band pattern-matching model of vowel perception

NASA Astrophysics Data System (ADS)

Hillenbrand, James M.; Houde, Robert A.

2003-02-01

The purpose of this paper is to propose and evaluate a new model of vowel perception which assumes that vowel identity is recognized by a template-matching process involving the comparison of narrow band input spectra with a set of smoothed spectral-shape templates that are learned through ordinary exposure to speech. In the present simulation of this process, the input spectra are computed over a sufficiently long window to resolve individual harmonics of voiced speech. Prior to template creation and pattern matching, the narrow band spectra are amplitude equalized by a spectrum-level normalization process, and the information-bearing spectral peaks are enhanced by a ``flooring'' procedure that zeroes out spectral values below a threshold function consisting of a center-weighted running average of spectral amplitudes. Templates for each vowel category are created simply by averaging the narrow band spectra of like vowels spoken by a panel of talkers. In the present implementation, separate templates are used for men, women, and children. The pattern matching is implemented with a simple city-block distance measure given by the sum of the channel-by-channel differences between the narrow band input spectrum (level-equalized and floored) and each vowel template. Spectral movement is taken into account by computing the distance measure at several points throughout the course of the vowel. The input spectrum is assigned to the vowel template that results in the smallest difference accumulated over the sequence of spectral slices. The model was evaluated using a large database consisting of 12 vowels in /hVd/ context spoken by 45 men, 48 women, and 46 children. The narrow band model classified vowels in this database with a degree of accuracy (91.4%) approaching that of human listeners.

An Assembly Funnel Makes Biomolecular Complex Assembly Efficient

PubMed Central

Zenk, John; Schulman, Rebecca

2014-01-01

Like protein folding and crystallization, the self-assembly of complexes is a fundamental form of biomolecular organization. While the number of methods for creating synthetic complexes is growing rapidly, most require empirical tuning of assembly conditions and/or produce low yields. We use coarse-grained simulations of the assembly kinetics of complexes to identify generic limitations on yields that arise because of the many simultaneous interactions allowed between the components and intermediates of a complex. Efficient assembly occurs when nucleation is fast and growth pathways are few, i.e. when there is an assembly “funnel”. For typical complexes, an assembly funnel occurs in a narrow window of conditions whose location is highly complex specific. However, by redesigning the components this window can be drastically broadened, so that complexes can form quickly across many conditions. The generality of this approach suggests assembly funnel design as a foundational strategy for robust biomolecular complex synthesis. PMID:25360818

Digitized detection of gamma-ray signals concentrated in narrow time windows for transient positron annihilation lifetime spectroscopy

NASA Astrophysics Data System (ADS)

Kinomura, A.; Suzuki, R.; Oshima, N.; O'Rourke, B. E.; Nishijima, T.; Ogawa, H.

2014-12-01

A pulsed slow-positron beam generated by an electron linear accelerator was directly used for positron annihilation lifetime spectroscopy without any positron storage devices. A waveform digitizer was introduced to simultaneously capture multiple gamma-ray signals originating from positron annihilation events during a single accelerator pulse. The positron pulse was chopped and bunched with the chopper signals also sent to the waveform digitizer. Time differences between the annihilation gamma-ray and chopper peaks were calculated and accumulated as lifetime spectra in a computer. The developed technique indicated that positron annihilation lifetime spectroscopy can be performed in a 20 μs time window at a pulse repetition rate synchronous with the linear accelerator. Lifetime spectra of a Kapton sheet and a thermally grown SiO2 layer on Si were successfully measured. Synchronization of positron lifetime measurements with pulsed ion irradiation was demonstrated by this technique.

A view of metals through the terahertz window

NASA Astrophysics Data System (ADS)

Dodge, Steve

2006-05-01

As electrons move through a metal, interaction with their environment tends to slow them down, causing the Drude peak in the optical conductivity to become narrower. The resulting peak width is typically in the terahertz frequency range that sits between microwaves the far infrared, too fast for conventional electronics and too slow for conventional infrared spectroscopy. With femtosecond laser techniques, however, coherent, broadband terahertz radiation can now be generated and detected with exquisite sensitivity, providing a new window onto electronic interactions in metals. I will discuss the application of this technique to a variety of metallic systems, including elemental lead, the nearly magnetic oxide metal CaRuO3, and CrV alloys that span the quantum phase transition from spin-density wave to paramagnetic metal. M. A. Gilmore, S. Kamal, D. M. Broun, and J. S. Dodge, Appl. Phys. Lett. 88, 141910 (2006).

Dynamic CRM occupancy reflects a temporal map of developmental progression.

PubMed

Wilczyński, Bartek; Furlong, Eileen E M

2010-06-22

Development is driven by tightly coordinated spatio-temporal patterns of gene expression, which are initiated through the action of transcription factors (TFs) binding to cis-regulatory modules (CRMs). Although many studies have investigated how spatial patterns arise, precise temporal control of gene expression is less well understood. Here, we show that dynamic changes in the timing of CRM occupancy is a prevalent feature common to all TFs examined in a developmental ChIP time course to date. CRMs exhibit complex binding patterns that cannot be explained by the sequence motifs or expression of the TFs themselves. The temporal changes in TF binding are highly correlated with dynamic patterns of target gene expression, which in turn reflect transitions in cellular function during different stages of development. Thus, it is not only the timing of a TF's expression, but also its temporal occupancy in refined time windows, which determines temporal gene expression. Systematic measurement of dynamic CRM occupancy may therefore serve as a powerful method to decode dynamic changes in gene expression driving developmental progression.

Disordered Supersolids in the Extended Bose-Hubbard Model

DOE PAGES

Lin, Fei; Maier, T. A.; Scarola, V. W.

2017-10-06

The extended Bose-Hubbard model captures the essential properties of a wide variety of physical systems including ultracold atoms and molecules in optical lattices, Josephson junction arrays, and certain narrow band superconductors. It exhibits a rich phase diagram including a supersolid phase where a lattice solid coexists with a superfluid. We use quantum Monte Carlo to study the supersolid part of the phase diagram of the extended Bose-Hubbard model on the simple cubic lattice. We add disorder to the extended Bose-Hubbard model and find that the maximum critical temperature for the supersolid phase tends to be suppressed by disorder. But wemore » also find a narrow parameter window in which the supersolid critical temperature is enhanced by disorder. Our results show that supersolids survive a moderate amount of spatial disorder and thermal fluctuations in the simple cubic lattice.« less

The source of the electric field in the nightside magnetosphere

NASA Technical Reports Server (NTRS)

Stern, D. P.

1975-01-01

In the open magnetosphere model magnetic field lines from the polar caps connect to the interplanetary magnetic field and conduct an electric field from interplanetary space to the polar ionosphere. By examining the magnetic flux involved it is concluded that only slightly more than half of the magnetic flux in the polar caps belongs to open field lines and that such field lines enter or leave the magnetosphere through narrow elongated windows stretching the tail. These window regions are identified with the tail's boundary region and shift their position with changes in the interplanetary magnetic field, in particular when a change of interplanetary magnetic sector occurs. The circuit providing electric current in the magnetopause and the plasma sheet is extended across those windows; thus energy is drained from the interplanetary electric field and an electric potential drop is produced across the plasma sheet. The polar cap receives its electric field from interplanetary space on the day side from open magnetic field lines and on the night side from closed field lines leading to the plasma sheet. The theory described provides improved understanding of magnetic flux bookkeeping, of the origin of Birkeland currents, and of the boundary layer of the geomagnetic tail.

High rate DC-reactive sputter deposition of Y 2O 3 film on the textured metal substrate for the superconducting coated conductor

NASA Astrophysics Data System (ADS)

Kim, Ho-Sup; Park, Chan; Ko, Rock-Kil; Shi, Dongqui; Chung, Jun-Ki; Ha, Hong-Soo; Park, Yu-Mi; Song, Kyu-Jeong; Youm, Do-Jun

2005-10-01

Y2O3 film was directly deposited on Ni-3at%W substrate by DC reactive sputtering. DC reactive sputtering was carried out using metallic Y target and water vapor for oxidizing the elements of metallic target on the substrate. The detailed conditions of DC reactive sputtering for depositions of Y2O3 films were investigated. The window of water vapor for proper growth of Y2O3 films was determined by sufficient oxidations of the Y2O3 films and the non-oxidation of the target surface, which was required for high rate sputtering. The window turned out to be fairly wide in the chamber used. As the sputtering power was raised, the deposition rate increased without narrowing the window. The fabricated Y2O3 films showed good texture qualities and surface morphologies. The YBCO film deposited directly on the Y2O3 buffered Ni-3at%W substrate showed Tc, Ic (77 K, self field), and Jc (77 K, self field) of 89 K, 64 A/cm and 1.1 MA/cm2, respectively.

Perceptual learning shapes multisensory causal inference via two distinct mechanisms.

PubMed

McGovern, David P; Roudaia, Eugenie; Newell, Fiona N; Roach, Neil W

2016-04-19

To accurately represent the environment, our brains must integrate sensory signals from a common source while segregating those from independent sources. A reasonable strategy for performing this task is to restrict integration to cues that coincide in space and time. However, because multisensory signals are subject to differential transmission and processing delays, the brain must retain a degree of tolerance for temporal discrepancies. Recent research suggests that the width of this 'temporal binding window' can be reduced through perceptual learning, however, little is known about the mechanisms underlying these experience-dependent effects. Here, in separate experiments, we measure the temporal and spatial binding windows of human participants before and after training on an audiovisual temporal discrimination task. We show that training leads to two distinct effects on multisensory integration in the form of (i) a specific narrowing of the temporal binding window that does not transfer to spatial binding and (ii) a general reduction in the magnitude of crossmodal interactions across all spatiotemporal disparities. These effects arise naturally from a Bayesian model of causal inference in which learning improves the precision of audiovisual timing estimation, whilst concomitantly decreasing the prior expectation that stimuli emanate from a common source.

Periods of cardiovascular susceptibility to hypoxia in embryonic american alligators (Alligator mississippiensis)

PubMed Central

Tate, Kevin B.; Rhen, Turk; Eme, John; Kohl, Zachary F.; Crossley, Janna; Elsey, Ruth M.

2016-01-01

During embryonic development, environmental perturbations can affect organisms' developing phenotype, a process known as developmental plasticity. Resulting phenotypic changes can occur during discrete, critical windows of development. Critical windows are periods when developing embryos are most susceptible to these perturbations. We have previously documented that hypoxia reduces embryo size and increases relative heart mass in American alligator, and this study identified critical windows when hypoxia altered morphological, cardiovascular function and cardiac gene expression of alligator embryos. We hypothesized that incubation in hypoxia (10% O2) would increase relative cardiac size due to cardiac enlargement rather than suppression of somatic growth. We exposed alligator embryos to hypoxia during discrete incubation periods to target windows where the embryonic phenotype is altered. Hypoxia affected heart growth between 20 and 40% of embryonic incubation, whereas somatic growth was affected between 70 and 90% of incubation. Arterial pressure was depressed by hypoxic exposure during 50–70% of incubation, whereas heart rate was depressed in embryos exposed to hypoxia during a period spanning 70–90% of incubation. Expression of Vegf and PdgfB was increased in certain hypoxia-exposed embryo treatment groups, and hypoxia toward the end of incubation altered β-adrenergic tone for arterial pressure and heart rate. It is well known that hypoxia exposure can alter embryonic development, and in the present study, we have identified brief, discrete windows that alter the morphology, cardiovascular physiology, and gene expression in embryonic American alligator. PMID:27101296

Temporal differentiation of pH-dependent capacitive current from dopamine.

PubMed

Yoshimi, Kenji; Weitemier, Adam

2014-09-02

Voltammetric recording of dopamine (DA) with fast-scan cyclic voltammetry (FSCV) on carbon fiber microelectrodes have been widely used, because of its high sensitivity to dopamine. However, since an electric double layer on a carbon fiber surface in a physiological ionic solution behaves as a capacitor, fast voltage manipulation in FSCV induces large capacitive current. The faradic current from oxidation/reduction of target chemicals must be extracted from this large background current. It is known that ionic shifts, including H(+), influence this capacitance, and pH shift can cause confounding influences on the FSCV recordings within a wide range of voltage. Besides FSCV with a triangular waveform, we have been using rectangular pulse voltammetry (RPV) for dopamine detection in the brain. In this method, the onset of a single pulse causes a large capacitive current, but unlike FSCV, the capacitive current is restricted to a narrow temporal window of just after pulse onset (<5 ms). In contrast, the peak of faradic current from dopamine oxidation occurs after a delay of more than a few milliseconds. Taking advantage of the temporal difference, we show that RPV could distinguish dopamine from pH shifts clearly and easily. In addition, the early onset current was useful to evaluate pH shifts. The narrow voltage window of our RPV pulse allowed a clear differentiation of dopamine and serotonin (5-HT), as we have shown previously. Additional recording with RPV, alongside FSCV, would improve identification of chemicals such as dopamine, pH, and 5-HT.

Interferometer for Space Station Windows

NASA Technical Reports Server (NTRS)

Hall, Gregory

2003-01-01

Inspection of space station windows for micrometeorite damage would be a difficult task insitu using current inspection techniques. Commercially available optical profilometers and inspection systems are relatively large, about the size of a desktop computer tower, and require a stable platform to inspect the test object. Also, many devices currently available are designed for a laboratory or controlled environments requiring external computer control. This paper presents an approach using a highly developed optical interferometer to inspect the windows from inside the space station itself using a self- contained hand held device. The interferometer would be capable as a minimum of detecting damage as small as one ten thousands of an inch in diameter and depth while interrogating a relatively large area. The current developmental state of this device is still in the proof of concept stage. The background section of this paper will discuss the current state of the art of profilometers as well as the desired configuration of the self-contained, hand held device. Then, a discussion of the developments and findings that will allow the configuration change with suggested approaches appearing in the proof of concept section.

Critical developmental windows for morphology and hematology revealed by intermittent and continuous hypoxic incubation in embryos of quail (Coturnix coturnix)

PubMed Central

Elmonoufy, Nourhan A.

2017-01-01

Hypoxia during embryonic growth in embryos is frequently a powerful determinant of development, but at least in avian embryos the effects appear to show considerable intra- and inter-specific variation. We hypothesized that some of this variation may arise from different protocols that may or may not result in exposure during the embryo’s critical window for hypoxic effects. To test this hypothesis, quail embryos (Coturnix coturnix) in the intact egg were exposed to hypoxia (~15% O2) during “early” (Day 0 through Day 5, abbreviated as D0-D5), “middle” (D6-D10) or “late” (D11-D15) incubation or for their entire 16–18 day incubation (“continuous hypoxia”) to determine critical windows for viability and growth. Viability, body mass, beak and toe length, heart mass, and hematology (hematocrit and hemoglobin concentration) were measured on D5, D10, D15 and at hatching typically between D16 and D18 Viability rate was ~50–70% immediately following the exposure period in the early, middle and late hypoxic groups, but viability improved in the early and late groups once normoxia was restored. Middle hypoxia groups showed continuing low viability, suggesting a critical period from D6-D10 for embryo viability. The continuous hypoxia group experienced viability reaching <10% after D15. Hypoxia, especially during late and continuous hypoxia, also inhibited growth of body, beak and toe when measured at D15. Full recovery to normal body mass upon hatching occurred in all other groups except for continuous hypoxia. Contrary to previous avian studies, heart mass, hematocrit and hemoglobin concentration were not altered by any hypoxic incubation pattern. Although hypoxia can inhibit embryo viability and organ growth during most incubation periods, the greatest effects result from continuous or middle incubation hypoxic exposure. Hypoxic inhibition of growth can subsequently be “repaired” by catch-up growth if a final period of normoxic development is available. Collectively, these data indicate a critical developmental window for hypoxia susceptibility during the mid-embryonic period of development. PMID:28926567

Critical developmental windows for morphology and hematology revealed by intermittent and continuous hypoxic incubation in embryos of quail (Coturnix coturnix).

PubMed

Burggren, Warren W; Elmonoufy, Nourhan A

2017-01-01

Hypoxia during embryonic growth in embryos is frequently a powerful determinant of development, but at least in avian embryos the effects appear to show considerable intra- and inter-specific variation. We hypothesized that some of this variation may arise from different protocols that may or may not result in exposure during the embryo's critical window for hypoxic effects. To test this hypothesis, quail embryos (Coturnix coturnix) in the intact egg were exposed to hypoxia (~15% O2) during "early" (Day 0 through Day 5, abbreviated as D0-D5), "middle" (D6-D10) or "late" (D11-D15) incubation or for their entire 16-18 day incubation ("continuous hypoxia") to determine critical windows for viability and growth. Viability, body mass, beak and toe length, heart mass, and hematology (hematocrit and hemoglobin concentration) were measured on D5, D10, D15 and at hatching typically between D16 and D18 Viability rate was ~50-70% immediately following the exposure period in the early, middle and late hypoxic groups, but viability improved in the early and late groups once normoxia was restored. Middle hypoxia groups showed continuing low viability, suggesting a critical period from D6-D10 for embryo viability. The continuous hypoxia group experienced viability reaching <10% after D15. Hypoxia, especially during late and continuous hypoxia, also inhibited growth of body, beak and toe when measured at D15. Full recovery to normal body mass upon hatching occurred in all other groups except for continuous hypoxia. Contrary to previous avian studies, heart mass, hematocrit and hemoglobin concentration were not altered by any hypoxic incubation pattern. Although hypoxia can inhibit embryo viability and organ growth during most incubation periods, the greatest effects result from continuous or middle incubation hypoxic exposure. Hypoxic inhibition of growth can subsequently be "repaired" by catch-up growth if a final period of normoxic development is available. Collectively, these data indicate a critical developmental window for hypoxia susceptibility during the mid-embryonic period of development.

Palaeoenvironment and Its Control on the Formation of Miocene Marine Source Rocks in the Qiongdongnan Basin, Northern South China Sea

PubMed Central

Li, Wenhao; Zhang, Zhihuan; Wang, Weiming; Lu, Shuangfang; Li, Youchuan; Fu, Ning

2014-01-01

The main factors of the developmental environment of marine source rocks in continental margin basins have their specificality. This realization, in return, has led to the recognition that the developmental environment and pattern of marine source rocks, especially for the source rocks in continental margin basins, are still controversial or poorly understood. Through the analysis of the trace elements and maceral data, the developmental environment of Miocene marine source rocks in the Qiongdongnan Basin is reconstructed, and the developmental patterns of the Miocene marine source rocks are established. This paper attempts to reveal the hydrocarbon potential of the Miocene marine source rocks in different environment and speculate the quality of source rocks in bathyal region of the continental slope without exploratory well. Our results highlight the palaeoenvironment and its control on the formation of Miocene marine source rocks in the Qiongdongnan Basin of the northern South China Sea and speculate the hydrocarbon potential of the source rocks in the bathyal region. This study provides a window for better understanding the main factors influencing the marine source rocks in the continental margin basins, including productivity, preservation conditions, and the input of terrestrial organic matter. PMID:25401132

Developmental Origins of Chronic Kidney Disease: Should We Focus on Early Life?

PubMed Central

Tain, You-Lin; Hsu, Chien-Ning

2017-01-01

Chronic kidney disease (CKD) is becoming a global burden, despite recent advances in management. CKD can begin in early life by so-called “developmental programming” or “developmental origins of health and disease” (DOHaD). Early-life insults cause structural and functional changes in the developing kidney, which is called renal programming. Epidemiological and experimental evidence supports the proposition that early-life adverse events lead to renal programming and make subjects vulnerable to developing CKD and its comorbidities in later life. In addition to low nephron endowment, several mechanisms have been proposed for renal programming. The DOHaD concept opens a new window to offset the programming process in early life to prevent the development of adult kidney disease, namely reprogramming. Here, we review the key themes on the developmental origins of CKD. We have particularly focused on the following areas: evidence from human studies support fetal programming of kidney disease; insight from animal models of renal programming; hypothetical mechanisms of renal programming; alterations of renal transcriptome in response to early-life insults; and the application of reprogramming interventions to prevent the programming of kidney disease. PMID:28208659

Child Health, Developmental Plasticity, and Epigenetic Programming

PubMed Central

Feil, R.; Constancia, M.; Fraga, M.; Junien, C.; Carel, J.-C.; Boileau, P.; Le Bouc, Y.; Deal, C. L.; Lillycrop, K.; Scharfmann, R.; Sheppard, A.; Skinner, M.; Szyf, M.; Waterland, R. A.; Waxman, D. J.; Whitelaw, E.; Ong, K.; Albertsson-Wikland, K.

2011-01-01

Plasticity in developmental programming has evolved in order to provide the best chances of survival and reproductive success to the organism under changing environments. Environmental conditions that are experienced in early life can profoundly influence human biology and long-term health. Developmental origins of health and disease and life-history transitions are purported to use placental, nutritional, and endocrine cues for setting long-term biological, mental, and behavioral strategies in response to local ecological and/or social conditions. The window of developmental plasticity extends from preconception to early childhood and involves epigenetic responses to environmental changes, which exert their effects during life-history phase transitions. These epigenetic responses influence development, cell- and tissue-specific gene expression, and sexual dimorphism, and, in exceptional cases, could be transmitted transgenerationally. Translational epigenetic research in child health is a reiterative process that ranges from research in the basic sciences, preclinical research, and pediatric clinical research. Identifying the epigenetic consequences of fetal programming creates potential applications in clinical practice: the development of epigenetic biomarkers for early diagnosis of disease, the ability to identify susceptible individuals at risk for adult diseases, and the development of novel preventive and curative measures that are based on diet and/or novel epigenetic drugs. PMID:20971919

Mapping the Trajectory of Socioeconomic Disparity in Working Memory: Parental and Neighborhood Factors

PubMed Central

Hackman, Daniel A.; Betancourt, Laura M.; Gallop, Robert; Romer, Daniel; Brodsky, Nancy L.; Hurt, Hallam; Farah, Martha J.

2014-01-01

Working memory (WM) is positively correlated with socioeconomic status (SES). It is not clear, however, if SES predicts the rate of WM development over time nor whether SES effects are specific to family rather than neighborhood SES. A community sample of children (n = 316) enrolled between ages 10 and 13 completed four annual assessments of WM. Lower parental education, but not neighborhood disadvantage, was associated with worse WM performance. Neither measure of SES was associated with the rate of developmental change. Consequently the SES disparity in WM is not a developmental lag which narrows nor an accumulating effect that becomes more pronounced. Rather, the relation between family SES and WM originates earlier in childhood and is stable though adolescence. PMID:24779417

Linewidth narrowing for 31Phosphorus MRI of cell membranes

NASA Astrophysics Data System (ADS)

Barrett, Sean; Frey, Merideth; Madri, Joseph; Michaud, Michael

2011-03-01

Most 31 P Magnetic Resonance Spectroscopy studies of tissues try to avoid contamination by a relatively large, but broad, spectral feature attributed to cell membrane phospholipids. MRI using this broad 31 P membrane spectrum is not even attempted, since the spatial resolution and signal-to-noise would be poor, relative to conventional MRI using the narrow 1 H water spectrum. This long-standing barrier has been overcome by a novel pulse sequence, recently discovered in fundamental quantum computation research, which narrows the broad 31 P spectrum by ~ 1000 × . Applying time-dependent gradients in synch with a repeating pulse block enables a new route to high spatial resolution, 3D 31 P MRI of the soft solid components of cells and tissues. So far, intact and sectioned samples of ex vivo fixed mouse organs have been imaged, with (sub-mm)3 voxels. Extending the reach of MRI to broad spectra in natural and artificial tissues opens a new window into cells, enabling progress in biomedical research. W.J. Thoma et al., J. MR 61, 141 (1985); E.J. Murphy et al., MR Med 12, 282 (1989); R. McNamara et al., NMR Biomed 7, 237 (1994).

Spectral Prior Image Constrained Compressed Sensing (Spectral PICCS) for Photon-Counting Computed Tomography

PubMed Central

Yu, Zhicong; Leng, Shuai; Li, Zhoubo; McCollough, Cynthia H.

2016-01-01

Photon-counting computed tomography (PCCT) is an emerging imaging technique that enables multi-energy imaging with only a single scan acquisition. To enable multi-energy imaging, the detected photons corresponding to the full x-ray spectrum are divided into several subgroups of bin data that correspond to narrower energy windows. Consequently, noise in each energy bin increases compared to the full-spectrum data. This work proposes an iterative reconstruction algorithm for noise suppression in the narrower energy bins used in PCCT imaging. The algorithm is based on the framework of prior image constrained compressed sensing (PICCS) and is called spectral PICCS; it uses the full-spectrum image reconstructed using conventional filtered back-projection as the prior image. The spectral PICCS algorithm is implemented using a constrained optimization scheme with adaptive iterative step sizes such that only two tuning parameters are required in most cases. The algorithm was first evaluated using computer simulations, and then validated by both physical phantoms and in-vivo swine studies using a research PCCT system. Results from both computer-simulation and experimental studies showed substantial image noise reduction in narrow energy bins (43~73%) without sacrificing CT number accuracy or spatial resolution. PMID:27551878

Spectral prior image constrained compressed sensing (spectral PICCS) for photon-counting computed tomography

NASA Astrophysics Data System (ADS)

Yu, Zhicong; Leng, Shuai; Li, Zhoubo; McCollough, Cynthia H.

2016-09-01

Photon-counting computed tomography (PCCT) is an emerging imaging technique that enables multi-energy imaging with only a single scan acquisition. To enable multi-energy imaging, the detected photons corresponding to the full x-ray spectrum are divided into several subgroups of bin data that correspond to narrower energy windows. Consequently, noise in each energy bin increases compared to the full-spectrum data. This work proposes an iterative reconstruction algorithm for noise suppression in the narrower energy bins used in PCCT imaging. The algorithm is based on the framework of prior image constrained compressed sensing (PICCS) and is called spectral PICCS; it uses the full-spectrum image reconstructed using conventional filtered back-projection as the prior image. The spectral PICCS algorithm is implemented using a constrained optimization scheme with adaptive iterative step sizes such that only two tuning parameters are required in most cases. The algorithm was first evaluated using computer simulations, and then validated by both physical phantoms and in vivo swine studies using a research PCCT system. Results from both computer-simulation and experimental studies showed substantial image noise reduction in narrow energy bins (43-73%) without sacrificing CT number accuracy or spatial resolution.

Multimodal Cues in the Socialization of Joint Attention in Young Children with Varying Degrees of Vision: Getting the POINT Even When You Can't See It

ERIC Educational Resources Information Center

Rickard, Carolyn

2013-01-01

Research on joint attention and language learning has focused primarily on cues requiring visual access. However, this narrow focus cannot account for the emergence of language among some congenitally blind children who develop language on the same developmental timescale as their sighted peers. Findings from this longitudinal, retrospective study…

Cross-Sectional Analysis of Time-Dependent Data: Mean-Induced Association in Age-Heterogeneous Samples and an Alternative Method Based on Sequential Narrow Age-Cohort Samples

ERIC Educational Resources Information Center

Hofer, Scott M.; Flaherty, Brian P.; Hoffman, Lesa

2006-01-01

The effect of time-related mean differences on estimates of association in cross-sectional studies has not been widely recognized in developmental and aging research. Cross-sectional studies of samples varying in age have found moderate to high levels of shared age-related variance among diverse age-related measures. These findings may be…

Monoamine-Sensitive Developmental Periods Impacting Adult Emotional and Cognitive Behaviors

PubMed Central

Suri, Deepika; Teixeira, Cátia M; Cagliostro, Martha K Caffrey; Mahadevia, Darshini; Ansorge, Mark S

2015-01-01

Development passes through sensitive periods, during which plasticity allows for genetic and environmental factors to exert indelible influence on the maturation of the organism. In the context of central nervous system development, such sensitive periods shape the formation of neurocircuits that mediate, regulate, and control behavior. This general mechanism allows for development to be guided by both the genetic blueprint as well as the environmental context. While allowing for adaptation, such sensitive periods are also vulnerability windows during which external and internal factors can confer risk to disorders by derailing otherwise resilient developmental programs. Here we review developmental periods that are sensitive to monoamine signaling and impact adult behaviors of relevance to psychiatry. Specifically, we review (1) a serotonin-sensitive period that impacts sensory system development, (2) a serotonin-sensitive period that impacts cognition, anxiety- and depression-related behaviors, and (3) a dopamine- and serotonin-sensitive period affecting aggression, impulsivity and behavioral response to psychostimulants. We discuss preclinical data to provide mechanistic insight, as well as epidemiological and clinical data to point out translational relevance. The field of translational developmental neuroscience has progressed exponentially providing solid conceptual advances and unprecedented mechanistic insight. With such knowledge at hand and important methodological innovation ongoing, the field is poised for breakthroughs elucidating the developmental origins of neuropsychiatric disorders, and thus understanding pathophysiology. Such knowledge of sensitive periods that determine the developmental trajectory of complex behaviors is a necessary step towards improving prevention and treatment approaches for neuropsychiatric disorders. PMID:25178408

Developmental pathways in infants from 4 to 24 months.

PubMed

Valla, L; Birkeland, M S; Hofoss, D; Slinning, K

2017-07-01

There has been limited epidemiological research describing population-based samples regarding developmental pathways throughout infancy, and the research that exists has revealed substantial diversity. Identifying predictors for developmental pathways can inform early intervention services. The Ages and Stages Questionnaire was used to measure communication, gross motor, fine motor, problem-solving and personal-social skills longitudinally in a large, population-based sample of 1555 infants recruited from well-baby clinics in five municipalities in southeast Norway. We conducted latent class analyses to identify common pathways within the five developmental areas. Our results indicated that most classes of infants showed generally positive and stable normative developmental pathways. However, for communication and gross motor areas, more heterogeneity was found. For gross motor development, a class of 10% followed a U-shaped curve. A class of 8% had a declining communication pathway and did not reach the level of the high stable communication class at 24 months. Low gestational age, low Apgar score, male sex, maternal depression symptoms, non-Scandinavian maternal ethnicity and high maternal education significantly predict less beneficial communication pathways. The results suggest that infants with low gestational age, low Apgar score, male sex and a mother with depression symptoms or non-Scandinavian ethnicity may be at risk of developing less beneficial developmental pathways, especially within the communication area. Targeting these infants for surveillance and support might be protective against delayed development in several areas during a critical window of development. © 2017 John Wiley & Sons Ltd.

Application study of filamentary composites in a commercial jet aircraft fuselage

NASA Technical Reports Server (NTRS)

Johnson, R. W.; June, R. R.

1972-01-01

A study of applications of filamentary composite materials to aircraft fuselage structure was performed. General design criteria were established and material studies conducted using the 727-200 forebody as the primary structural component. Three design approaches to the use of composites were investigated: uniaxial reinforcement of metal structure, uniaxial and biaxial reinforcement of metal structure, and an all-composite design. Materials application studies for all three concepts were conducted on fuselage shell panels, keel beam, floor beams, floor panels, body frames, fail-safe straps, and window frames. Cost benefit studies were conducted and developmental program costs estimated. On the basis of weight savings, cost effectiveness, developmental program costs, and potential for early application on commercial aircraft, the unaxial design is recommended for a 5-year flight service evaluation program.

Parent-reported Temperament Trajectories among Infant Siblings of Children with Autism

PubMed Central

del Rosario, Mithi; Gillespie-Lynch, Kristen; Johnson, Scott; Sigman, Marian; Hutman, Ted

2013-01-01

Temperament atypicalities have been documented in infancy and early development in children who develop autism spectrum disorders (ASD). The current study investigates whether there are differences in developmental trajectories of temperament between infants and toddlers with and without ASD. Parents of infant siblings of children with autism completed the Carey Temperament Scales about their child at 6, 12, 18, 24, and 36 months of age. Temperament trajectories of children with ASD reflected increases over time in activity level, and decreasing adaptability and approach behaviors relative to high-risk typically developing children. This study is the first to compare temperament trajectories between high-risk typically developing infants and infants subsequently diagnosed with ASD in the developmental window when overt symptoms of ASD first emerge. PMID:23820765

Prenatal Testosterone Programming of Insulin Resistance in the Female Sheep.

PubMed

Puttabyatappa, Muraly; Padmanabhan, Vasantha

2017-01-01

Insulin resistance, a common feature of metabolic disorders such as obesity, nonalcoholic fatty liver disease, metabolic syndrome, and polycystic ovary syndrome, is a risk factor for development of diabetes. Because sex hormones orchestrate the establishment of sex-specific behavioral, reproductive, and metabolic differences, a role for them in the developmental origin of insulin resistance is also to be expected. Female sheep exposed to male levels of testosterone during fetal life serve as an excellent translational model for delineating programming of insulin resistance. This chapter summarizes the ontogeny of insulin resistance, the tissue-specific changes in insulin sensitivity, and the various factors that are involved in the programming and maintenance of the insulin resistance in adult female sheep that were developmentally exposed to fetal male levels of testosterone during the sexual-differentiation window.

Narrowing the gap: effects of intervention on developmental trajectories in autism.

PubMed

Klintwall, Lars; Eldevik, Sigmund; Eikeseth, Svein

2015-01-01

Although still a matter of some debate, there is a growing body of research supporting Early and Intensive Behavioral Intervention as the intervention of choice for children with autism. Learning rate is an alternative to change in standard scores as an outcome measure in studies of early intervention. Learning rates can be displayed graphically as developmental trajectories, which are easy to understand and avoid some of the counter-intuitive properties of changes in standard scores. The data used in this analysis were from 453 children with autism, previously described by Eldevik et al. Children receiving Early and Intensive Behavioral Intervention exhibited significantly steeper developmental trajectories than children in the control group, in both intelligence and adaptive behaviors. However, there was a considerable variability in individual learning rates within the group receiving Early and Intensive Behavioral Intervention. This variability could partly be explained by the intensity of the treatment, partly by children's intake intelligence quotient age-equivalents. Age at intake did not co-vary with learning rate. © The Author(s) 2013.

Discrimination of side-window glass of Korean autos by laser ablation inductively coupled plasma mass spectrometry.

PubMed

Lee, Sin-Woo; Ryu, Jong-Sik; Min, Ji-Sook; Choi, Man-Yong; Lee, Kwang-Sik; Shin, Woo-Jin

2016-07-15

Fragments of glass from cars are often found at crime scenes and can be crucial evidence for solving the crime. The glass fragments are important as trace evidence at crime scenes related to car accidents and burgled homes. By identifying the origin of glass fragments, it is possible to infer the identity of a suspect. Our results represent a promising approach to a thorough forensic investigation of car glass. Thirty-five samples from the side windows of cars produced and used in South Korea were collected from the official agencies of five car manufacturers and from two glassmakers. In addition, 120 samples from side mirrors were collected from the same suppliers as well as from small businesses. Their chemical compositions (including Pb isotopes) were analyzed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and linear discriminant analysis (LDA) was performed. The percentages of major elements (Si, Ca, and Fe) in side-window glass varied within narrow ranges (30.0 ± 2.36%, 5.93 ± 0.52%, and 0.33 ± 0.05%, respectively), while the differences among Pb isotope ratios were not significant. In contrast, light rare earth elements (LREEs) were different from each glassmaker. From the LDA, the types of side-window glass were successfully discriminated according to car manufacturer, glassmaker, and even glass thickness. However, glass from side mirrors cannot be used for good forensic identifiers. Discrimination techniques for side-window glass, although not for side mirrors, using chemical compositions combined with multivariate statistical analyses provide evidence for forensic investigations. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Developmental Changes in Organization of Structural Brain Networks

PubMed Central

Khundrakpam, Budhachandra S.; Reid, Andrew; Brauer, Jens; Carbonell, Felix; Lewis, John; Ameis, Stephanie; Karama, Sherif; Lee, Junki; Chen, Zhang; Das, Samir; Evans, Alan C.; Ball, William S.; Byars, Anna Weber; Schapiro, Mark; Bommer, Wendy; Carr, April; German, April; Dunn, Scott; Rivkin, Michael J.; Waber, Deborah; Mulkern, Robert; Vajapeyam, Sridhar; Chiverton, Abigail; Davis, Peter; Koo, Julie; Marmor, Jacki; Mrakotsky, Christine; Robertson, Richard; McAnulty, Gloria; Brandt, Michael E.; Fletcher, Jack M.; Kramer, Larry A.; Yang, Grace; McCormack, Cara; Hebert, Kathleen M.; Volero, Hilda; Botteron, Kelly; McKinstry, Robert C.; Warren, William; Nishino, Tomoyuki; Robert Almli, C.; Todd, Richard; Constantino, John; McCracken, James T.; Levitt, Jennifer; Alger, Jeffrey; O'Neil, Joseph; Toga, Arthur; Asarnow, Robert; Fadale, David; Heinichen, Laura; Ireland, Cedric; Wang, Dah-Jyuu; Moss, Edward; Zimmerman, Robert A.; Bintliff, Brooke; Bradford, Ruth; Newman, Janice; Evans, Alan C.; Arnaoutelis, Rozalia; Bruce Pike, G.; Louis Collins, D.; Leonard, Gabriel; Paus, Tomas; Zijdenbos, Alex; Das, Samir; Fonov, Vladimir; Fu, Luke; Harlap, Jonathan; Leppert, Ilana; Milovan, Denise; Vins, Dario; Zeffiro, Thomas; Van Meter, John; Lange, Nicholas; Froimowitz, Michael P.; Botteron, Kelly; Robert Almli, C.; Rainey, Cheryl; Henderson, Stan; Nishino, Tomoyuki; Warren, William; Edwards, Jennifer L.; Dubois, Diane; Smith, Karla; Singer, Tish; Wilber, Aaron A.; Pierpaoli, Carlo; Basser, Peter J.; Chang, Lin-Ching; Koay, Chen Guan; Walker, Lindsay; Freund, Lisa; Rumsey, Judith; Baskir, Lauren; Stanford, Laurence; Sirocco, Karen; Gwinn-Hardy, Katrina; Spinella, Giovanna; McCracken, James T.; Alger, Jeffry R.; Levitt, Jennifer; O'Neill, Joseph

2013-01-01

Recent findings from developmental neuroimaging studies suggest that the enhancement of cognitive processes during development may be the result of a fine-tuning of the structural and functional organization of brain with maturation. However, the details regarding the developmental trajectory of large-scale structural brain networks are not yet understood. Here, we used graph theory to examine developmental changes in the organization of structural brain networks in 203 normally growing children and adolescents. Structural brain networks were constructed using interregional correlations in cortical thickness for 4 age groups (early childhood: 4.8–8.4 year; late childhood: 8.5–11.3 year; early adolescence: 11.4–14.7 year; late adolescence: 14.8–18.3 year). Late childhood showed prominent changes in topological properties, specifically a significant reduction in local efficiency, modularity, and increased global efficiency, suggesting a shift of topological organization toward a more random configuration. An increase in number and span of distribution of connector hubs was found in this age group. Finally, inter-regional connectivity analysis and graph-theoretic measures indicated early maturation of primary sensorimotor regions and protracted development of higher order association and paralimbic regions. Our finding reveals a time window of plasticity occurring during late childhood which may accommodate crucial changes during puberty and the new developmental tasks that an adolescent faces. PMID:22784607

When blood is thinner than water.

PubMed

Gude, Dilip; Abbas, Aslam; Mohiuddin, Hina

2013-01-01

Antagonists of vitamin K dependant clotting factors are commonly used as treatment/prophylaxis for anticoagulation. Due to their narrow therapeutic window, a wide range of complications including death may occur. International normalized ratio (INR) is monitored to measure adequacy/excess of anticoagulation. There is a plethora of risk factors that may contribute to the uncontrollably high INR values. We describe our experience of a case of deep venous thrombosis wherein the patient had an overshoot of INR during anticoagulation therapy. We review the literature and discuss management in such scenarios.

Side effects of the strain-doping approach to develop optical materials based on Ge

NASA Astrophysics Data System (ADS)

Escalante, Jose M.

2018-05-01

Following the strain-doping approach for development of Ge based optical gain material, we have studied the impact of doping and strain on the optical properties of Germanium. Emphasizing the importance of the bandgap narrowing effect due to doping on the emission wavelength, we have computed a strain-doping-energy maps, which provide the strain and doping windows that can be considered in order to achieve a specific value of the Γ bandgap. Finally, we discuss the polarization of the emitted light, and its dependence on strains.

Analysis of the Effect of Environmental Conditions in Conducting Amphibious Assaults Using a Ship Simulator/Vessel-Response Model Proof-of-Concept Study

DTIC Science & Technology

2017-05-01

Analyzing these factors enables a planner to develop an axis-of-advance that a vessel can easily maintain, as well as to reduce the travel time from...operational risk by testing the feasibility of the navigability of an area; 2) determining the capacity and timing of that operation; 3) defining the...conditions at this location dictate that only a narrow window of time is available for conducting surface ship-to- shore operations. The vessel

Resonant kink-antikink scattering through quasinormal modes

NASA Astrophysics Data System (ADS)

Dorey, Patrick; Romańczukiewicz, Tomasz

2018-04-01

We investigate the role that quasinormal modes can play in kink-antikink collisions, via an example based on a deformation of the ϕ4 model. We find that narrow quasinormal modes can store energy during collision processes and later return it to the translational degrees of freedom. Quasinormal modes also decay, which leads to energy leakage, causing a closing of resonance windows and an increase of the critical velocity. We observe similar phenomena in an effective model, a small modification of the collective-coordinate approach to the ϕ4 model.

Do mitochondria play a role in remodelling lace plant leaves during programmed cell death?

PubMed

Lord, Christina E N; Wertman, Jaime N; Lane, Stephanie; Gunawardena, Arunika H L A N

2011-06-06

Programmed cell death (PCD) is the regulated death of cells within an organism. The lace plant (Aponogeton madagascariensis) produces perforations in its leaves through PCD. The leaves of the plant consist of a latticework of longitudinal and transverse veins enclosing areoles. PCD occurs in the cells at the center of these areoles and progresses outwards, stopping approximately five cells from the vasculature. The role of mitochondria during PCD has been recognized in animals; however, it has been less studied during PCD in plants. The following paper elucidates the role of mitochondrial dynamics during developmentally regulated PCD in vivo in A. madagascariensis. A single areole within a window stage leaf (PCD is occurring) was divided into three areas based on the progression of PCD; cells that will not undergo PCD (NPCD), cells in early stages of PCD (EPCD), and cells in late stages of PCD (LPCD). Window stage leaves were stained with the mitochondrial dye MitoTracker Red CMXRos and examined. Mitochondrial dynamics were delineated into four categories (M1-M4) based on characteristics including distribution, motility, and membrane potential (ΔΨm). A TUNEL assay showed fragmented nDNA in a gradient over these mitochondrial stages. Chloroplasts and transvacuolar strands were also examined using live cell imaging. The possible importance of mitochondrial permeability transition pore (PTP) formation during PCD was indirectly examined via in vivo cyclosporine A (CsA) treatment. This treatment resulted in lace plant leaves with a significantly lower number of perforations compared to controls, and that displayed mitochondrial dynamics similar to that of non-PCD cells. Results depicted mitochondrial dynamics in vivo as PCD progresses within the lace plant, and highlight the correlation of this organelle with other organelles during developmental PCD. To the best of our knowledge, this is the first report of mitochondria and chloroplasts moving on transvacuolar strands to form a ring structure surrounding the nucleus during developmental PCD. Also, for the first time, we have shown the feasibility for the use of CsA in a whole plant system. Overall, our findings implicate the mitochondria as playing a critical and early role in developmentally regulated PCD in the lace plant.

Phelan-McDermid syndrome presenting with developmental delays and facial dysmorphisms.

PubMed

Kim, Yoon-Myung; Choi, In-Hee; Kim, Jun Suk; Kim, Ja Hye; Cho, Ja Hyang; Lee, Beom Hee; Kim, Gu-Hwan; Choi, Jin-Ho; Seo, Eul-Ju; Yoo, Han-Wook

2016-11-01

Phelan-McDermid syndrome is a rare genetic disorder caused by the terminal or interstitial deletion of the chromosome 22q13.3. Patients with this syndrome usually have global developmental delay, hypotonia, and speech delays. Several putative genes such as the SHANK3 , RAB , RABL2B , and IB2 are responsible for the neurological features. This study describes the clinical features and outcomes of Korean patients with Phelan-McDermid syndrome. Two patients showing global developmental delay, hypotonia, and speech delay were diagnosed with Phelan-McDermid syndrome via chromosome analysis, fluorescent in situ hybridization, and multiplex ligation-dependent probe amplification analysis. Brain magnetic resonance imaging of Patients 1 and 2 showed delayed myelination and severe communicating hydrocephalus, respectively. Electroencephalography in patient 2 showed high amplitude spike discharges from the left frontotemporoparietal area, but neither patient developed seizures. Kidney ultrasonography of both the patients revealed multicystic kidney disease and pelviectasis, respectively. Patient 2 experienced recurrent respiratory infections, and chest computed tomography findings demonstrated laryngotracheomalacia and bronchial narrowing. He subsequently died because of heart failure after a ventriculoperitoneal shunt operation at 5 months of age. Patient 1, who is currently 20 months old, has been undergoing rehabilitation therapy. However, global developmental delay was noted, as determines using the Korean Infant and Child Development test, the Denver developmental test, and the Bayley developmental test. This report describes the clinical features, outcomes, and molecular genetic characteristics of two Korean patients with Phelan-McDermid syndrome.

The mechanism of action of doxofylline is unrelated to HDAC inhibition, PDE inhibition or adenosine receptor antagonism.

PubMed

van Mastbergen, J; Jolas, T; Allegra, L; Page, C P

2012-02-01

Xanthines such as theophylline have been used in the treatment of lung diseases since the early 1900's, but have a major drawback of a very narrow therapeutic window and many drug/drug interactions. This means that plasma levels have to be measured regularly and can make the use of theophylline problematic. With the increasing availability of other classes of drugs for the treatment of respiratory diseases, this has limited the use of xanthines, despite their clear clinical benefit in the treatment of patients with asthma and COPD. Doxofylline is a xanthine molecule having both bronchodilator and anti-inflammatory activity with an improved therapeutic window over conventional xanthines such as theophylline. However, the mechanistic basis of this improved therapeutic window is not understood. The present study has investigated some pharmacological activities of doxofylline in comparison with theophylline. Doxofylline does not directly inhibit any of the known HDAC enzymes, and did not inhibit any PDE enzyme sub types or act as an antagonist at any of the known adenosine receptors, except for PDE2A(1), and adenosine A(2A) and only at the highest tested concentration (10(-4) M). These results may explain the improved tolerability profile of doxofylline compared with theophylline. Copyright © 2011. Published by Elsevier Ltd.

Stabilizing Ir(001) Epitaxy on Yttria-Stabilized Zirconia Using a Thin Ir Seed Layer Grown by Pulsed Laser Deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, Lisha; Jacobs, Christopher B.; Rouleau, Christopher M.

In this paper, we demonstrate the reproducible epitaxial growth of 100 nm thick Ir(001) films on a heteroepitaxial stack consisting of 5 nm Ir and 100 nm yttria-stabilized zirconia (YSZ) grown on Si(001) substrates. It is shown that a 5 nm thick Ir layer grown by pulsed laser deposition in the same chamber as the YSZ film without breaking the vacuum is the key to stabilizing Ir(001) epitaxial growth. Growth of the Ir seed layer with pure (001) orientation occurs only in a narrow growth temperature window from 550 to 750 °C, and the fraction of Ir(111) increases at substratemore » temperatures outside of this window. The Ir seed layer prevents exposure of the YSZ film to air during sample transfer and enables highly reproducible Ir(001) heteroepitaxy on YSZ buffered Si(001). In contrast, if Ir is grown directly on a bare YSZ layer that was exposed to ambient conditions, the films are prone to change orientation to (111). These results reveal that preserving the chemical and structural purity of the YSZ surface is imperative for achieving Ir(001) epitaxy. The narrow range of the mosaic spread values from eight experiments demonstrates the high yield and high reproducibility of Ir(001) heteroepitaxy by this approach. Lastly, the improved Ir(001) epitaxial growth method is of great significance for integrating a variety of technologically important materials such as diamond, graphene, and functional oxides on a Si platform.« less

Stabilizing Ir(001) Epitaxy on Yttria-Stabilized Zirconia Using a Thin Ir Seed Layer Grown by Pulsed Laser Deposition

DOE PAGES

Fan, Lisha; Jacobs, Christopher B.; Rouleau, Christopher M.; ...

2016-11-18

In this paper, we demonstrate the reproducible epitaxial growth of 100 nm thick Ir(001) films on a heteroepitaxial stack consisting of 5 nm Ir and 100 nm yttria-stabilized zirconia (YSZ) grown on Si(001) substrates. It is shown that a 5 nm thick Ir layer grown by pulsed laser deposition in the same chamber as the YSZ film without breaking the vacuum is the key to stabilizing Ir(001) epitaxial growth. Growth of the Ir seed layer with pure (001) orientation occurs only in a narrow growth temperature window from 550 to 750 °C, and the fraction of Ir(111) increases at substratemore » temperatures outside of this window. The Ir seed layer prevents exposure of the YSZ film to air during sample transfer and enables highly reproducible Ir(001) heteroepitaxy on YSZ buffered Si(001). In contrast, if Ir is grown directly on a bare YSZ layer that was exposed to ambient conditions, the films are prone to change orientation to (111). These results reveal that preserving the chemical and structural purity of the YSZ surface is imperative for achieving Ir(001) epitaxy. The narrow range of the mosaic spread values from eight experiments demonstrates the high yield and high reproducibility of Ir(001) heteroepitaxy by this approach. Lastly, the improved Ir(001) epitaxial growth method is of great significance for integrating a variety of technologically important materials such as diamond, graphene, and functional oxides on a Si platform.« less

Targeting Oxidative Stress and Aberrant Critical Period Plasticity in the Developmental Trajectory to Schizophrenia

PubMed Central

Do, Kim Q.; Cuenod, Michel; Hensch, Takao K.

2015-01-01

Schizophrenia is a neurodevelopmental disorder reflecting a convergence of genetic risk and early life stress. The slow progression to first psychotic episode represents both a window of vulnerability as well as opportunity for therapeutic intervention. Here, we consider recent neurobiological insight into the cellular and molecular components of developmental critical periods and their vulnerability to redox dysregulation. In particular, the consistent loss of parvalbumin-positive interneuron (PVI) function and their surrounding perineuronal nets (PNNs) as well as myelination in patient brains is consistent with a delayed or extended period of circuit instability. This linkage to critical period triggers (PVI) and brakes (PNN, myelin) implicates mistimed trajectories of brain development in mental illness. Strategically introduced antioxidant treatment or later reinforcement of molecular brakes may then offer a novel prophylactic psychiatry. PMID:26032508

A developmental perspective on the link between parents' employment and children's obesity.

PubMed

Crosnoe, Robert; Dunifon, Rachel

2017-01-01

Despite public concerns about the negative implications of the increased labor force participation of mothers for child development, decades of research have revealed few risks and some benefits. One potential risk-a consistently observed association between maternal employment and childhood obesity-offers a window into how some dimensions of family health may be undermined by work in an economic and policy context that is not family friendly. The purpose of this article is to identify ways that a developmental perspective can enrich the literature on how children's weight may be related to the work experiences of both mothers and fathers across diverse populations, a literature that heretofore has been dominated by economic and demographic perspectives, focused almost solely on women, and largely ignored racial/ethnic variation. After reviewing the extant literature, we put forward a conceptual model that uses ecological and developmental insights to identify the mechanisms by which parents' employment might matter to children's weight and discuss this model in the context of the contemporary landscape of family policy. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Transient inhibition of the ERK pathway prevents cerebellar developmental defects and improves long-term motor functions in murine models of neurofibromatosis type 1.

PubMed

Kim, Edward; Wang, Yuan; Kim, Sun-Jung; Bornhorst, Miriam; Jecrois, Emmanuelle S; Anthony, Todd E; Wang, Chenran; Li, Yi E; Guan, Jun-Lin; Murphy, Geoffrey G; Zhu, Yuan

2014-12-23

Individuals with neurofibromatosis type 1 (NF1) frequently exhibit cognitive and motor impairments and characteristics of autism. The cerebellum plays a critical role in motor control, cognition, and social interaction, suggesting that cerebellar defects likely contribute to NF1-associated neurodevelopmental disorders. Here we show that Nf1 inactivation during early, but not late stages of cerebellar development, disrupts neuronal lamination, which is partially caused by overproduction of glia and subsequent disruption of the Bergmann glia (BG) scaffold. Specific Nf1 inactivation in glutamatergic neuronal precursors causes premature differentiation of granule cell (GC) precursors and ectopic production of unipolar brush cells (UBCs), indirectly disrupting neuronal migration. Transient MEK inhibition during a neonatal window prevents cerebellar developmental defects and improves long-term motor performance of Nf1-deficient mice. This study reveals essential roles of Nf1 in GC/UBC migration by generating correct numbers of glia and controlling GC/UBC fate-specification/differentiation, identifying a therapeutic prevention strategy for multiple NF1-associcated developmental abnormalities.

Bivalence Mn5O8 with hydroxylated interphase for high-voltage aqueous sodium-ion storage

PubMed Central

Shan, Xiaoqiang; Charles, Daniel S.; Lei, Yinkai; Qiao, Ruimin; Wang, Guofeng; Yang, Wanli; Feygenson, Mikhail; Su, Dong; Teng, Xiaowei

2016-01-01

Aqueous electrochemical energy storage devices have attracted significant attention owing to their high safety, low cost and environmental friendliness. However, their applications have been limited by a narrow potential window (∼1.23 V), beyond which the hydrogen and oxygen evolution reactions occur. Here we report the formation of layered Mn5O8 pseudocapacitor electrode material with a well-ordered hydroxylated interphase. A symmetric full cell using such electrodes demonstrates a stable potential window of 3.0 V in an aqueous electrolyte, as well as high energy and power performance, nearly 100% coulombic efficiency and 85% energy efficiency after 25,000 charge–discharge cycles. The interplay between hydroxylated interphase on the surface and the unique bivalence structure of Mn5O8 suppresses the gas evolution reactions, offers a two-electron charge transfer via Mn2+/Mn4+ redox couple, and provides facile pathway for Na-ion transport via intra-/inter-layer defects of Mn5O8. PMID:27845345

Dynamic chirp control of all-optical format-converted pulsed data from a multi-wavelength inverse-optical-comb injected semiconductor optical amplifier.

PubMed

Lin, Gong-Ru; Pan, Ci-Ling; Yu, Kun-Chieh

2007-10-01

By spectrally and temporally reshaping the gain-window of a traveling-wave semiconductor optical amplifier (TWSOA) with a backward injected multi- or single-wavelength inverse-optical-comb, we theoretically and experimentally investigate the dynamic frequency chirp of the all-optical 10GBit/s Return-to-Zero (RZ) data-stream format-converted from the TWSOA under strong cross-gain depletion scheme. The multi-wavelength inverse-optical-comb injection effectively depletes the TWSOA gain spectrally and temporally, remaining a narrow gain-window and a reduced spectral linewidth and provide a converted RZ data with a smaller peak-to-peak frequency chirp of 6.7 GHz. Even at high inverse-optical-comb injection power and highly biased current condition for improving the operational bit-rate, the chirp of the multi-wavelength-injection converted RZ pulse is still 2.1-GHz smaller than that obtained by using single-wavelength injection at a cost of slight pulse-width broadening by 1 ps.

Processing ISS Images of Titan's Surface

NASA Technical Reports Server (NTRS)

Perry, Jason; McEwen, Alfred; Fussner, Stephanie; Turtle, Elizabeth; West, Robert; Porco, Carolyn; Knowles, Ben; Dawson, Doug

2005-01-01

One of the primary goals of the Cassini-Huygens mission, in orbit around Saturn since July 2004, is to understand the surface and atmosphere of Titan. Surface investigations are primarily accomplished with RADAR, the Visual and Infrared Mapping Spectrometer (VIMS), and the Imaging Science Subsystem (ISS) [1]. The latter two use methane "windows", regions in Titan's reflectance spectrum where its atmosphere is most transparent, to observe the surface. For VIMS, this produces clear views of the surface near 2 and 5 microns [2]. ISS uses a narrow continuum band filter (CB3) at 938 nanometers. While these methane windows provide our best views of the surface, the images produced are not as crisp as ISS images of satellites like Dione and Iapetus [3] due to the atmosphere. Given a reasonable estimate of contrast (approx.30%), the apparent resolution of features is approximately 5 pixels due to the effects of the atmosphere and the Modulation Transfer Function of the camera [1,4]. The atmospheric haze also reduces contrast, especially with increasing emission angles [5].

Digitized detection of gamma-ray signals concentrated in narrow time windows for transient positron annihilation lifetime spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinomura, A., E-mail: a.kinomura@aist.go.jp; Suzuki, R.; Oshima, N.

2014-12-15

A pulsed slow-positron beam generated by an electron linear accelerator was directly used for positron annihilation lifetime spectroscopy without any positron storage devices. A waveform digitizer was introduced to simultaneously capture multiple gamma-ray signals originating from positron annihilation events during a single accelerator pulse. The positron pulse was chopped and bunched with the chopper signals also sent to the waveform digitizer. Time differences between the annihilation gamma-ray and chopper peaks were calculated and accumulated as lifetime spectra in a computer. The developed technique indicated that positron annihilation lifetime spectroscopy can be performed in a 20 μs time window at amore » pulse repetition rate synchronous with the linear accelerator. Lifetime spectra of a Kapton sheet and a thermally grown SiO{sub 2} layer on Si were successfully measured. Synchronization of positron lifetime measurements with pulsed ion irradiation was demonstrated by this technique.« less

P-channel differential multiple-time programmable memory cells by laterally coupled floating metal gate fin field-effect transistors

NASA Astrophysics Data System (ADS)

Wang, Tai-Min; Chien, Wei-Yu; Hsu, Chia-Ling; Lin, Chrong Jung; King, Ya-Chin

2018-04-01

In this paper, we present a new differential p-channel multiple-time programmable (MTP) memory cell that is fully compatible with advanced 16 nm CMOS fin field-effect transistors (FinFET) logic processes. This differential MTP cell stores complementary data in floating gates coupled by a slot contact structure, which make different read currents possible on a single cell. In nanoscale CMOS FinFET logic processes, the gate dielectric layer becomes too thin to retain charges inside floating gates for nonvolatile data storage. By using a differential architecture, the sensing window of the cell can be extended and maintained by an advanced blanket boost scheme. The charge retention problem in floating gate cells can be improved by periodic restoring lost charges when significant read window narrowing occurs. In addition to high programming efficiency, this p-channel MTP cells also exhibit good cycling endurance as well as disturbance immunity. The blanket boost scheme can remedy the charge loss problem under thin gate dielectrics.

Electronic tunability of zero dispersion wavelengths in a spiral photonic crystal fiber for supercontinuum generation in the communication window

NASA Astrophysics Data System (ADS)

Hossain, Md. Nazmul; Alam, M. Shah; Mohsin, K. M.; Hasan, Dihan Md. Nuruddin

2011-08-01

A liquid crystal infiltrated spiral photonic crystal fiber (LCSPCF) is presented here for electrical tuning of two zero dispersion wavelengths (ZDWs) in the present communication window. The proposed LCSPCF shows tunability of the ZDWs from 1433 nm to 2136 nm due to the rotation of the infiltrated LC mesogen induced by the external electric field. Therefore, the ZDW can easily be shifted towards the available pump wavelength for effective supercontinuum generation (SCG) over a broad wavelength region. By tuning the bandwidth (BW) in between the two ZDWs the extension of the generated supercontinuum (SC) spectrum can also be electrically controlled. This will help the SCG in our desired band with optimum power budget. Moreover, the index guiding mechanism of the proposed soft glass LCSPCF shows improvement over the narrow operational bandwidth and the low nonlinearity of the band-gap guided silica LCPCF. Additionally, the solid core of the proposed LCSPCF is less lossy than the previously proposed liquid crystal core PCF.

Bivalence Mn5O8 with hydroxylated interphase for high-voltage aqueous sodium-ion storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shan, Xiaoqiang; Charles, Daniel S.; Lei, Yinkai

Aqueous electrochemical energy storage devices have attracted significant attention owing to their high safety, low cost, and environmental friendliness. However, their applications have been limited by a narrow potential window (~1.23 V), beyond which the hydrogen and oxygen evolution reactions occur. Here, we report the formation of layered Mn 5O 8 pseudocapacitor electrode material with a well ordered hydroxylated interphase. A symmetric full cell using such electrodes demonstrates a stable potential window of 3.0 V in an aqueous electrolyte, as well as high energy and power performance, nearly 100% coulombic efficiency and 85% energy efficiency after 25,000 charge-discharge cycles. Furthermore,more » the interplay between hydroxylated interphase on the surface and the unique bivalence structure of Mn 5O 8 suppresses the gas evolution reactions, offers a two-electron charge transfer via Mn 2+/Mn 4+ redox couple, and provides facile pathway for Na-ion transport via intra-/inter-layer defects of Mn 5O 8.« less

Adhesion signals of phospholipid vesicles at an electrified interface.

PubMed

DeNardis, Nadica Ivošević; Žutić, Vera; Svetličić, Vesna; Frkanec, Ruža

2012-09-01

General adhesion behavior of phospholipid vesicles was examined in a wide range of potentials at the mercury electrode by recording time-resolved adhesion signals. It was demonstrated that adhesion-based detection is sensitive to polar headgroups in phospholipid vesicles. We identified a narrow potential window around the point of zero charge of the electrode where the interaction of polar headgroups of phosphatidylcholine vesicles with the substrate is manifested in the form of bidirectional signals. The bidirectional signal is composed of the charge flow due to the nonspecific interaction of vesicle adhesion and spreading and of the charge flow due to a specific interaction of the negatively charged electrode and the most exposed positively charged choline headgroups. These signals are expected to appear only when the electrode surface charge density is less than the surface charge density of the choline groups at the contact interface. In comparison, for the negatively charged phosphatidylserine vesicles, we identified the potential window at the mercury electrode where charge compensation takes place, and bidirectional signals were not detected.

Bivalence Mn5O8 with hydroxylated interphase for high-voltage aqueous sodium-ion storage

DOE PAGES

Shan, Xiaoqiang; Charles, Daniel S.; Lei, Yinkai; ...

2016-11-15

Aqueous electrochemical energy storage devices have attracted significant attention owing to their high safety, low cost, and environmental friendliness. However, their applications have been limited by a narrow potential window (~1.23 V), beyond which the hydrogen and oxygen evolution reactions occur. Here, we report the formation of layered Mn 5O 8 pseudocapacitor electrode material with a well ordered hydroxylated interphase. A symmetric full cell using such electrodes demonstrates a stable potential window of 3.0 V in an aqueous electrolyte, as well as high energy and power performance, nearly 100% coulombic efficiency and 85% energy efficiency after 25,000 charge-discharge cycles. Furthermore,more » the interplay between hydroxylated interphase on the surface and the unique bivalence structure of Mn 5O 8 suppresses the gas evolution reactions, offers a two-electron charge transfer via Mn 2+/Mn 4+ redox couple, and provides facile pathway for Na-ion transport via intra-/inter-layer defects of Mn 5O 8.« less

Plasma interactions determine the composition in pulsed laser deposited thin films

NASA Astrophysics Data System (ADS)

Chen, Jikun; Döbeli, Max; Stender, Dieter; Conder, Kazimierz; Wokaun, Alexander; Schneider, Christof W.; Lippert, Thomas

2014-09-01

Plasma chemistry and scattering strongly affect the congruent, elemental transfer during pulsed laser deposition of target metal species in an oxygen atmosphere. Studying the plasma properties of La0.6Sr0.4MnO3, we demonstrate for as grown La0.6Sr0.4MnO3-δ films that a congruent transfer of metallic species is achieved in two pressure windows: ˜10-3 mbar and ˜2 × 10-1 mbar. In the intermediate pressure range, La0.6Sr0.4MnO3-δ becomes cation deficient and simultaneously almost fully stoichiometric in oxygen. Important for thin film growth is the presence of negative atomic oxygen and under which conditions positive metal-oxygen ions are created in the plasma. This insight into the plasma chemistry shows why the pressure window to obtain films with a desired composition and crystalline structure is narrow and requires a careful adjustment of the process parameters.

An approach to emotion recognition in single-channel EEG signals: a mother child interaction

NASA Astrophysics Data System (ADS)

Gómez, A.; Quintero, L.; López, N.; Castro, J.

2016-04-01

In this work, we perform a first approach to emotion recognition from EEG single channel signals extracted in four (4) mother-child dyads experiment in developmental psychology. Single channel EEG signals are analyzed and processed using several window sizes by performing a statistical analysis over features in the time and frequency domains. Finally, a neural network obtained an average accuracy rate of 99% of classification in two emotional states such as happiness and sadness.

Developmental Origins of Common Disease: Epigenetic Contributions to Obesity.

PubMed

Kappil, Maya; Wright, Robert O; Sanders, Alison P

2016-08-31

The perinatal period is a window of susceptibility for later life disease. Recent epigenetic findings are beginning to increase our understanding of the molecular mechanisms that may contribute to the programming of obesity. This review summarizes recent evidence that supports the role of epigenetically mediated early life programming in the later onset of obesity. Establishing such links between environmental exposures and modifiable molecular changes ultimately holds promise to inform interventional efforts toward alleviating the environmentally mediated onset of obesity.

Developmental Origins of Common Disease: Epigenetic Contributions to Obesity

PubMed Central

Kappil, Maya; Wright, Robert O.; Sanders, Alison P.

2016-01-01

The perinatal period is a window of susceptibility for later life disease. Recent epigenetic findings are beginning to increase our understanding of the molecular mechanisms that may contribute to the programming of obesity. This review summarizes recent evidence that supports the role of epigenetically mediated early life programming in the later onset of obesity. Establishing such links between environmental exposures and modifiable molecular changes ultimately holds promise to inform interventional efforts toward alleviating the environmentally mediated onset of obesity. PMID:27216778

Influence of gravity and light on the developmental polarity of Ceratopteris richardii fern spores

NASA Technical Reports Server (NTRS)

Edwards, E. S.; Roux, S. J.

1998-01-01

The polarity of germinating single-celled spores of the fern Ceratopteris richardii Brogn. is influenced by gravity during a time period prior to the first cellular division designated a "polarity-determination window". After this window closes, control of polarity is seen in the downward (with respect to gravity) migration of the nucleus along the proximal face of the spore and the subsequent downward growth of the primary rhizoid. When spores are germinated on a clinostat the direction of nuclear migration and subsequent primary rhizoid growth is random. However, in each case the direction of nuclear migration predicts the direction of rhizoid elongation. Although it is the most obvious movement, the downward migration is not the first movement of the nucleus. During the polarity-determination window, the nucleus moves randomly within a region centered behind the trilete marking. While the polarity of many fern spores has been reported to be controlled by light, spores of C. richardii are the first documented to have their polarity influenced by gravity. Directional white light also affects the polarity of these spores, but this influence is slight and is secondary to that of gravity.

Phase separation of comb polymer nanocomposite melts.

PubMed

Xu, Qinzhi; Feng, Yancong; Chen, Lan

2016-02-07

In this work, the spinodal phase demixing of branched comb polymer nanocomposite (PNC) melts is systematically investigated using the polymer reference interaction site model (PRISM) theory. To verify the reliability of the present method in characterizing the phase behavior of comb PNCs, the intermolecular correlation functions of the system for nonzero particle volume fractions are compared with our molecular dynamics simulation data. After verifying the model and discussing the structure of the comb PNCs in the dilute nanoparticle limit, the interference among the side chain number, side chain length, nanoparticle-monomer size ratio and attractive interactions between the comb polymer and nanoparticles in spinodal demixing curves is analyzed and discussed in detail. The results predict two kinds of distinct phase separation behaviors. One is called classic fluid phase boundary, which is mediated by the entropic depletion attraction and contact aggregation of nanoparticles at relatively low nanoparticle-monomer attraction strength. The second demixing transition occurs at relatively high attraction strength and involves the formation of an equilibrium physical network phase with local bridging of nanoparticles. The phase boundaries are found to be sensitive to the side chain number, side chain length, nanoparticle-monomer size ratio and attractive interactions. As the side chain length is fixed, the side chain number has a large effect on the phase behavior of comb PNCs; with increasing side chain number, the miscibility window first widens and then shrinks. When the side chain number is lower than a threshold value, the phase boundaries undergo a process from enlarging the miscibility window to narrowing as side chain length increases. Once the side chain number overtakes this threshold value, the phase boundary shifts towards less miscibility. With increasing nanoparticle-monomer size ratio, a crossover of particle size occurs, above which the phase separation is consistent with that of chain PNCs. The miscibility window for this condition gradually narrows while the other parameters of the PNCs system are held constant. These results indicate that the present PRISM theory can give molecular-level details of the underlying mechanisms of the comb PNCs. It is hoped that the results can be used to provide useful guidance for the future design control of novel, thermodynamically stable comb PNCs.

Cyclopamine-induced synophthalmia in sheep: defining a critical window and toxicokinetic evaluation.

PubMed

Welch, K D; Panter, K E; Lee, S T; Gardner, D R; Stegelmeier, B L; Cook, D

2009-07-01

Cyclopamine, a steroidal alkaloid, from the plant Veratrum californicum is teratogenic, causing a range of different birth defects. The critical window for cyclopamine-induced synophthalmia formation has been reported to be gestational day (GD) 14. The objectives of this study were to better describe cyclopamine-induced craniofacial deformities, to better define the window of susceptibility to synophthalmia formation, and to characterize cyclopamine toxicokinetics in sheep. Ewes were dosed i.v. with purified cyclopamine for toxicokinetic analysis. Another four groups of ewes were dosed orally twice daily with 0.88 g/kg of V. californicum on GD 13, 14 or 15 or consecutively on GD days 13-15. Pregnancy and pre-partum fetal malformations were determined by ultrasound imaging on GD 60. At parturition lambs were assessed for gross malformations. The elimination half-life of cyclopamine in ewes was determined to be 1.1 +/- 0.1 h. The rapid clearance of cyclopamine indicates that ingestion of V. californicum must occur during a very narrow window for synophthalmia formation to occur. Ewes dosed with V. californicum on GD 13 or 14 had lambs with various craniofacial malformations including cyclopia, maxillary dysplasia and mandibular micrognathia. Ewes dosed on GD 15 delivered normal lambs. Ewes dosed consecutively on GD 13-15 were not pregnant at GD 60 and Veratrum-induced embryonic death was assumed to be the cause. Interestingly, lambs with cyclopia were smaller, under-developed and appeared premature even though their twin appeared fully developed. Initial evaluations suggest this was due to placental dysplasia. 2009 by John Wiley & Sons, Ltd.

Heat shock protein expression as guidance for the therapeutic window of retinal laser therapy

NASA Astrophysics Data System (ADS)

Wang, Jenny; Huie, Philip; Dalal, Roopa; Lee, Seungjun; Tan, Gavin; Lee, Daeyoung; Lavinksy, Daniel; Palanker, Daniel

2016-03-01

Unlike conventional photocoagulation, non-damaging retinal laser therapy (NRT) limits laser-induced heating to stay below the retinal damage threshold and therefore requires careful dosimetry. Without the adverse effects associated with photocoagulation, NRT can be applied to critical areas of the retina and repeatedly to manage chronic disorders. Although the clinical benefits of NRT have been demonstrated, the mechanism of therapeutic effect and width of the therapeutic window below damage threshold are not well understood. Here, we measure activation of heat shock response via laser-induced hyperthermia as one indication of cellular response. A 577 nm laser is used with the Endpoint Management (EpM) user interface, a titration algorithm, to set experimental pulse energies relative to a barely visible titration lesion. Live/dead staining and histology show that the retinal damage threshold in rabbits is at 40% of titration energy on EpM scale. Heat shock protein 70 (HSP70) expression in the retinal pigment epithelium (RPE) was detected by whole-mount immunohistochemistry after different levels of laser treatment. We show HSP70 expression in the RPE beginning at 25% of titration energy indicating that there is a window for NRT between 25% and 40% with activation of the heat shock protein expression in response to hyperthermia. HSP70 expression is also seen at the perimeter of damaging lesions, as expected based on a computational model of laser heating. Expression area for each pulse energy setting varied between laser spots due to pigmentation changes, indicating the relatively narrow window of non-damaging activation and highlighting the importance of proper titration.

14. View toward the northwest corner of the basement in ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. View toward the northwest corner of the basement in the north segment of the building. Portions of the basement floor are earth, and portions are concrete. For some undetermined reason an unbonded, narrow panel of brick occurs in the west (left) wall. A corbeled brick footing is seen under this panel, as if the panel is carrying a concentrated load. An identical element occurs to the left, outside the camera's view. These 'columns' may support the second-story brick facade over the ground floor store windows. Credit GADA/MRM. - Stroud Building, 31-33 North Central Avenue, Phoenix, Maricopa County, AZ

Modeling of planar varactor frequency multiplier devices with blocking barriers

NASA Technical Reports Server (NTRS)

Lieneweg, Udo; Tolmunen, T. J.; Frerking, Margaret A.; Maserjian, Joseph

1992-01-01

Models for optimization of planar frequency triplers with symmetrical C-V curves are presented. Role and limitation of various blocking barriers (oxide, Mott, heterojunction) are discussed. Devices with undoped drift regions (BIN) have moderate efficiency but a broad range of power operation, whereas devices with doped drift regions (BNN) have high efficiency in a narrow power window. In particular, an upper power limit of the BNN is caused by electron velocity saturation. Implementations in SiO2/Si and AlAs/GaAs and means for increasing the power of BNN structures are considered.

Bioactive Mimetics of Conotoxins and other Venom Peptides

PubMed Central

Duggan, Peter J.; Tuck, Kellie L.

2015-01-01

Ziconotide (Prialt®), a synthetic version of the peptide ω-conotoxin MVIIA found in the venom of a fish-hunting marine cone snail Conus magnus, is one of very few drugs effective in the treatment of intractable chronic pain. However, its intrathecal mode of delivery and narrow therapeutic window cause complications for patients. This review will summarize progress in the development of small molecule, non-peptidic mimics of Conotoxins and a small number of other venom peptides. This will include a description of how some of the initially designed mimics have been modified to improve their drug-like properties. PMID:26501323

Modeling of planar varactor frequency multiplier devices with blocking barriers

NASA Astrophysics Data System (ADS)

Lieneweg, Udo; Tolmunen, T. J.; Frerking, Margaret A.; Maserjian, Joseph

1992-05-01

Models for optimization of planar frequency triplers with symmetrical C-V curves are presented. Role and limitation of various blocking barriers (oxide, Mott, heterojunction) are discussed. Devices with undoped drift regions (BIN) have moderate efficiency but a broad range of power operation, whereas devices with doped drift regions (BNN) have high efficiency in a narrow power window. In particular, an upper power limit of the BNN is caused by electron velocity saturation. Implementations in SiO2/Si and AlAs/GaAs and means for increasing the power of BNN structures are considered.

Infrared Radiation Filament And Metnod Of Manufacture

DOEpatents

Johnson, Edward A.

1998-11-17

An improved IR radiation source is provided by the invention. A radiation filament has a textured surface produced by seeded ion bombardment of a metal foil which is cut to a serpentine shape and mounted in a windowed housing. Specific ion bombardment texturing techniques tune the surface to maximize emissions in the desired wavelength range and to limit emissions outside that narrow range, particularly at longer wavelengths. A combination of filament surface texture, thickness, material, shape and power circuit feedback control produce wavelength controlled and efficient radiation at much lower power requirements than devices of the prior art.

Exploiting the extraordinary genetic polymorphism of ciona for developmental genetics with whole genome sequencing.

PubMed

Abdul-Wajid, Sarah; Veeman, Michael T; Chiba, Shota; Turner, Thomas L; Smith, William C

2014-05-01

Studies in tunicates such as Ciona have revealed new insights into the evolutionary origins of chordate development. Ciona populations are characterized by high levels of natural genetic variation, between 1 and 5%. This variation has provided abundant material for forward genetic studies. In the current study, we make use of deep sequencing and homozygosity mapping to map spontaneous mutations in outbred populations. With this method we have mapped two spontaneous developmental mutants. In Ciona intestinalis we mapped a short-tail mutation with strong phenotypic similarity to a previously identified mutant in the related species Ciona savignyi. Our bioinformatic approach mapped the mutation to a narrow interval containing a single mutated gene, α-laminin3,4,5, which is the gene previously implicated in C. savignyi. In addition, we mapped a novel genetic mutation disrupting neural tube closure in C. savignyi to a T-type Ca(2+) channel gene. The high efficiency and unprecedented mapping resolution of our study is a powerful advantage for developmental genetics in Ciona, and may find application in other outbred species.

Recruitment and Retention of Pregnant Women for a Behavioral Intervention: Lessons from the Maternal Adiposity, Metabolism, and Stress (MAMAS) Study

PubMed Central

Laraia, Barbara A.; Adler, Nancy; Vieten, Cassandra; Thomas, Melanie; Epel, Elissa

2013-01-01

Introduction Recruiting participants for research studies can be challenging. Many studies fall short of their target or must prolong recruitment to reach it. We examined recruitment and retention strategies and report lessons learned in a behavioral intervention developmental trial to encourage healthy pregnancy weight gain and stress reduction in low-income overweight pregnant women. Methods In the San Francisco Bay area from February 2010 through March 2011, we used direct and indirect strategies to recruit English-speaking overweight and obese pregnant women who were aged 18 to 45, were in the early stages of pregnancy, and who had an annual household income less than 500% of the federal poverty guidelines. Eligible women who consented participated in focus groups or an 8-week behavioral intervention. We identified successful recruiting strategies and sites and calculated the percentage of women who were enrolled and retained. Results Of 127 women screened for focus group participation, 69 were eligible and enrolled. A total of 57 women participated in 9 focus groups and 3 women completed individual interviews for a completion rate of 87%. During recruitment for the intervention, we made contact with 204 women; 135 were screened, 33% were eligible, and 69.1% of eligible women enrolled. At 1 month postpartum, 82.6% of eligible women completed an assessment. Recruiting at hospital-based prenatal clinics was the highest-yielding strategy. Conclusion The narrow window of eligibility for enrolling early stage pregnant women in a group intervention presents obstacles. In-person recruitment was the most successful strategy; establishing close relationships with providers, clinic staff, social service providers, and study participants was essential to successful recruitment and retention. PMID:23469765

Assessment of Toxicological Perturbations and Variants of Pancreatic Islet Development in the Zebrafish Model

PubMed Central

Sant, Karilyn E.; Jacobs, Haydee M.; Xu, Jiali; Borofski, Katrina A.; Moss, Larry G.; Moss, Jennifer B.; Timme-Laragy, Alicia R.

2016-01-01

The pancreatic islets, largely comprised of insulin-producing beta cells, play a critical role in endocrine signaling and glucose homeostasis. Because they have low levels of antioxidant defenses and a high perfusion rate, the endocrine islets may be a highly susceptible target tissue of chemical exposures. However, this endpoint, as well as the integrity of the surrounding exocrine pancreas, is often overlooked in studies of developmental toxicology. Disruption of development by toxicants can alter cell fate and migration, resulting in structural alterations that are difficult to detect in mammalian embryo systems, but that are easily observed in the zebrafish embryo model (Danio rerio). Using endogenously expressed fluorescent protein markers for developing zebrafish beta cells and exocrine pancreas tissue, we documented differences in islet area and incidence rates of islet morphological variants in zebrafish embryos between 48 and 96 h post fertilization (hpf), raised under control conditions commonly used in embryotoxicity assays. We identified critical windows for chemical exposures during which increased incidences of endocrine pancreas abnormalities were observed following exposure to cyclopamine (2–12 hpf), Mono-2-ethylhexyl phthalate (MEHP) (3–48 hpf), and Perfluorooctanesulfonic acid (PFOS) (3–48 hpf). Both islet area and length of the exocrine pancreas were sensitive to oxidative stress from exposure to the oxidant tert-butyl hydroperoxide during a highly proliferative critical window (72 hpf). Finally, pancreatic dysmorphogenesis following developmental exposures is discussed with respect to human disease. PMID:28393070

Epigenetic impacts of endocrine disruptors in the brain☆

PubMed Central

Walker, Deena M.; Gore, Andrea C.

2017-01-01

The acquisition of reproductive competence is organized and activated by steroid hormones acting upon the hypothalamus during critical windows of development. This review describes the potential role of epigenetic processes, particularly DNA methylation, in the regulation of sexual differentiation of the hypothalamus by hormones. We examine disruption of these processes by endocrine-disrupting chemicals (EDCs) in an age-, sex-, and region-specific manner, focusing on how perinatal EDCs act through epigenetic mechanisms to reprogram DNA methylation and sex steroid hormone receptor expression throughout life. These receptors are necessary for brain sexual differentiation and their altered expression may underlie disrupted reproductive physiology and behavior. Finally, we review the literature on histone modifications and non-coding RNA involvement in brain sexual differentiation and their perturbation by EDCs. By putting these data into a sex and developmental context we conclude that perinatal EDC exposure alters the developmental trajectory of reproductive neuroendocrine systems in a sex-specific manner. PMID:27663243

The inability to mentally represent action may be associated with performance deficits in children with developmental coordination disorder.

PubMed

Gabbard, Carl; Bobbio, Tatiana

2011-03-01

Several research studies indicate that children with developmental coordination disorder (DCD) show delays with an array of perceptual-motor skills. One of the explanations, based on limited research, is that these children have problems generating and/or monitoring a mental (action) representation of intended actions, termed the "internal modeling deficit" (IMD) hypothesis. According to the hypothesis, children with DCD have significant limitations in their ability to accurately generate and utilize internal models of motor planning and control. The focus of this review is on one of the methods used to examine action representation-motor imagery, which theorists argue provides a window into the process of action representation (e.g., Jeannerod, 2001 . Neural simulation of action: A unifying mechanism for motor cognition. Neuroimage, 14, 103-109.). Included in the review are performance studies of typically developing and DCD children, and possible brain structures involved.

Childhood Stuttering – Where are we and Where are we going?

PubMed Central

Smith, Anne; Weber, Christine

2017-01-01

Remarkable progress has been made over the past two decades in expanding our understanding of the behavioral, peripheral physiological, and central neurophysiological bases of stuttering in early childhood. It is clear that stuttering is a neurodevelopmental disorder characterized by atypical development of speech motor planning and execution networks. The speech motor system must interact in complex ways with neural systems mediating language, other cognitive, and emotional processes. During the time window when stuttering typically appears and follows its path to either recovery or persistence, all of these neurobehavioral systems are undergoing rapid and dramatic developmental changes. We summarize our current understanding of the various developmental trajectories relevant for the understanding of stuttering in early childhood. We also present theoretical and experimental approaches that we believe will be optimal for even more rapid progress toward developing better and more targeted treatment for stuttering in the preschool children who are more likely to persist in stuttering. PMID:27701705

OsWOX3A is involved in negative feedback regulation of the gibberellic acid biosynthetic pathway in rice (Oryza sativa).

PubMed

Cho, Sung-Hwan; Kang, Kiyoon; Lee, Sang-Hwa; Lee, In-Jung; Paek, Nam-Chon

2016-03-01

The plant-specific WUSCHEL-related homeobox (WOX) nuclear proteins have important roles in the transcriptional regulation of many developmental processes. Among the rice (Oryza sativa) WOX proteins, a loss of OsWOX3A function in narrow leaf2 (nal2) nal3 double mutants (termed nal2/3) causes pleiotropic effects, such as narrow and curly leaves, opened spikelets, narrow grains, more tillers, and fewer lateral roots, but almost normal plant height. To examine OsWOX3A function in more detail, transgenic rice overexpressing OsWOX3A (OsWOX3A-OX) were generated; unexpectedly, all of them consistently exhibited severe dwarfism with very short and wide leaves, a phenotype that resembles that of gibberellic acid (GA)-deficient or GA-insensitive mutants. Exogenous GA3 treatment fully rescued the developmental defects of OsWOX3A-OX plants, suggesting that constitutive overexpression of OsWOX3A downregulates GA biosynthesis. Quantitative analysis of GA intermediates revealed significantly reduced levels of GA20 and bioactive GA1 in OsWOX3A-OX, possibly due to downregulation of the expression of KAO, which encodes ent-kaurenoic acid oxidase, a GA biosynthetic enzyme. Yeast one-hybrid and electrophoretic mobility shift assays revealed that OsWOX3A directly interacts with the KAO promoter. OsWOX3A expression is drastically and temporarily upregulated by GA3 and downregulated by paclobutrazol, a blocker of GA biosynthesis. These data indicate that OsWOX3A is a GA-responsive gene and functions in the negative feedback regulation of the GA biosynthetic pathway for GA homeostasis to maintain the threshold levels of endogenous GA intermediates throughout development. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Early Methylprednisolone Treatment Can Stabilize the Blood-Optic Nerve Barrier in a Rat Model of Anterior Ischemic Optic Neuropathy (rAION).

PubMed

Huang, Tzu-Lun; Wen, Yao-Tseng; Chang, Chung-Hsing; Chang, Shu-Wen; Lin, Kuan-Hung; Tsai, Rong-Kung

2017-03-01

We investigated whether methylprednisolone (MP) treatment halting retinal ganglion cell (RGC) death and having anti-inflammatory effect over a narrow therapeutic window affects the integrity of the blood-optic nerve barrier (BOB) in a rat model of ischemic optic neuropathy (rAION). The optic nerve (ON) vascular permeability was determined by Evans blue extravasation. Changes in the levels of TNF-α and IL-1β cytokines were analyzed using quantitative RT-PCR (qRT-PCR) from day 1 to day 5 post-rAION. Rats were treated with MP starting on days 0, 1, 2, and 7 post-rAION. The survival and apoptosis of the RGCs were determined by fluoroGold labeling and TUNEL assay, and the visual function was assessed with flash visual-evoked potentials (FVEPs) 4 weeks postinfarct. Inflammation of the ON was detected by immunohistochemical staining of ED1. Macrophage recruitment in the ON was significantly reduced, which was compatible with the reduction in ON vascular permeability, after MP treatment starting on days 0 and 1 postinsult compared to PBS treatment (both, P < 0.05). There was significant reduction in TNF-α and IL-1β expression in MP-treated rats (all, P < 0.05). The survival number and antiapoptotic effect on RGCs, and the P1-N2 FVEP amplitude significantly improved with MP treatment starting on days 0 and 1 (all, P < 0.05). Early treatment with MP halts RGC death and mitigates macrophage infiltration with decreased expression of proinflammatory cytokines in acute rAION. The very narrow therapeutic window is related to the quick stabilization of the disrupted BOB by early application of MP.

The narrow therapeutic window of glycated hemoglobin and assay variability.

PubMed

Hosseini, S S; Bibler, I; Charles, M A

1999-12-01

Glycated hemoglobin is measured by a variety of assays, each of which has a unique normal level. Our purpose is to show that among the different assays available in the United States, using the same patient's blood sample, assay results may vary widely and may more or less easily achieve a glycated hemoglobin value within the normal range. The following assays were compared using the same patient's blood sample for each pair of assays: glycohemoglobin affinity assay (GHB Reader; Isolab, Akron, OH) versus gel electrophoresis assay (n = 76); Isolab versus ion capture assay (IMX; Abbott Laboratories, Irving, TX) (n = 57); monoclonal antibody assay (DCA2000; Bayer Diagnostics, Pittsburgh, PA) versus IMX (n = 100); and high-performance liquid chromatography (HPLC) assay (Bio-Rad Variant A1c; Bio-Rad Laboratories, Richmond, CA) versus IMX assay (n = 55). Our analyses indicate that a relative ranking can be established for the ease of achieving a normal glycated hemoglobin level. The ranking indicates that the most stringent or difficult assays for achieving a normal level are the Isolab and DCA2000 assays. The intermediate assays are the IMX and Bio-Rad Variant, and the easiest method for achieving a normal value is the gel electrophoresis assay. Our results indicate that various glycated hemoglobin assays vary widely and are associated with more or less difficulty for an individual patient to achieve a glycated hemoglobin level within the normal range. These results are especially significant with respect to (1) the clinically narrow therapeutic window of glycated hemoglobin values in type 1 diabetes to avoid rapidly advancing severe hypoglycemia rates and chronic microvascular complication rates, and (2) the glycated hemoglobin threshold for rapidly advancing macrovascular disease in both type 1 and type 2 patients.

Early direct-injection, low-temperature combustion of diesel fuel in an optical engine utilizing a 15-hole, dual-row, narrow-included-angle nozzle.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gehrke, Christopher R.; Radovanovic, Michael S.; Milam, David M.

2008-04-01

Low-temperature combustion of diesel fuel was studied in a heavy-duty, single-cylinder optical engine employing a 15-hole, dual-row, narrow-included-angle nozzle (10 holes x 70/mD and 5 holes x 35/mD) with 103-/gmm-diameter orifices. This nozzle configuration provided the spray targeting necessary to contain the direct-injected diesel fuel within the piston bowl for injection timings as early as 70/mD before top dead center. Spray-visualization movies, acquired using a high-speed camera, show that impingement of liquid fuel on the piston surface can result when the in-cylinder temperature and density at the time of injection are sufficiently low. Seven single- and two-parameter sweeps around amore » 4.82-bar gross indicated mean effective pressure load point were performed to map the sensitivity of the combustion and emissions to variations in injection timing, injection pressure, equivalence ratio, simulated exhaust-gas recirculation, intake temperature, intake boost pressure, and load. High-speed movies of natural luminosity were acquired by viewing through a window in the cylinder wall and through a window in the piston to provide quasi-3D information about the combustion process. These movies revealed that advanced combustion phasing resulted in intense pool fires within the piston bowl, after the end of significant heat release. These pool fires are a result of fuel-films created when the injected fuel impinged on the piston surface. The emissions results showed a strong correlation with pool-fire activity. Smoke and NO/dx emissions rose steadily as pool-fire intensity increased, whereas HC and CO showed a dramatic increase with near-zero pool-fire activity.« less

Impact of the deposition conditions of buffer and windows layers on lowering the metastability effects in Cu(In,Ga)Se2/Zn(S,O)-based solar cell

NASA Astrophysics Data System (ADS)

Naghavi, Negar; Hildebrandt, Thibaud; Bouttemy, Muriel; Etcheberry, Arnaud; Lincot, Daniel

2016-02-01

The highest and most reproducible (Cu(In,Ga)Se2 (CIGSe) based solar-cell efficiencies are obtained by use of a very thin n-type CdS layer deposited by chemical bath deposition (CBD). However because of both Cadmium's adverse environmental impact and the narrow bandgap of CdS (2.4-2.5 eV) one of the major objectives in the field of CIGSe technology remains the development and implementation in the production line of Cd-free buffer layers. The CBDZn( S,O) remains one the most studied buffer layer for replacing the CdS in Cu(In,Ga)Se2-based solar cells and has already demonstrated its potential to lead to high-efficiency solar cells up to 22.3%. However one of the key issue to implement a CBD-Zn(S,O) process in a CIGSe production line is the cells stability, which depends both on the deposition conditions of CBD-Zn(S,O) and on a good band alignment between CIGSe/Zn(S,O)/windows layers. The most common window layers applied in CIGSe solar cells consist of two layers : a thin (50-100 nm) and highly resistive i-ZnO layer deposited by magnetron sputtering and a transparent conducting 300-500 nm ZnO:Al layer. In the case of CBD-Zn(S,O) buffer layer, the nature and deposition conditions of both Zn(S,O) and the undoped window layer can strongly influence the performance and stability of cells. The present contribution will be specially focused on the effect of condition growth of CBD-Zn(S,O) buffer layers and the impact of the composition and deposition conditions of the undoped window layers such as ZnxMgyO or ZnxSnyO on the stability and performance of these solar cells.

Role of the immune modulator programmed cell death-1 during development and apoptosis of mouse retinal ganglion cells

PubMed Central

Chen, Ling; Sham, Caroline W.; Chan, Ann M.; Francisco, Loise M.; Wu, Yin; Mareninov, Sergey; Sharpe, Arlene H.; Freeman, Gordon J.; Yang, Xian-Jie; Braun, Jonathan; Gordon, Lynn K.

2011-01-01

PURPOSE Mammalian programmed cell death-1 (PD-1) is a membrane-associated receptor regulating the balance between T cell activation, tolerance and immunopathology, however its role in neurons has not yet been defined. We investigate the hypothesis that PD-1 signaling actively promotes retinal ganglion cell (RGC) death within the developing mouse retina. METHODS Mature retinal cell types expressing PD-1 were identified by immunofluorescence staining of vertical retina sections; developmental expression was localized by immunostaining and quantified by Western analysis. PD-1 involvement in developmental RGC survival was assessed in vitro using retina explants and in vivo using PD-1 knockout mice. PD-1 ligand gene expression was detected by RT-PCR. RESULTS PD-1 is expressed in most adult RGCs, and undergoes dynamic upregulation during the early postnatal window of retinal cell maturation and physiological programmed cell death (PCD). In vitro blockade of PD-1 signaling during this time selectively increases survival of RGCs. Furthermore, PD-1 deficient mice show a selective increase in RGC number in the neonatal retina at the peak of developmental RGC death. Lastly, throughout postnatal retina maturation, we find gene expression of both immune PD-1 ligand genes, PD-L1 and PD-L2. CONCLUSIONS These findings collectively support a novel role for a PD-1-mediated signaling pathway in developmental PCD during postnatal RGC maturation. PMID:19420345

Kinase-activating and kinase-impaired cardio-facio-cutaneous syndrome alleles have activity during zebrafish development and are sensitive to small molecule inhibitors.

PubMed

Anastasaki, Corina; Estep, Anne L; Marais, Richard; Rauen, Katherine A; Patton, E Elizabeth

2009-07-15

The Ras/MAPK pathway is critical for human development and plays a central role in the formation and progression of most cancers. Children born with germ-line mutations in BRAF, MEK1 or MEK2 develop cardio-facio-cutaneous (CFC) syndrome, an autosomal dominant syndrome characterized by a distinctive facial appearance, heart defects, skin and hair abnormalities and mental retardation. CFC syndrome mutations in BRAF promote both kinase-activating and kinase-impaired variants. CFC syndrome has a progressive phenotype, and the availability of clinically active inhibitors of the MAPK pathway prompts the important question as to whether such inhibitors might be therapeutically effective in the treatment of CFC syndrome. To study the developmental effects of CFC mutant alleles in vivo, we have expressed a panel of 28 BRAF and MEK alleles in zebrafish embryos to assess the function of human disease alleles and available chemical inhibitors of this pathway. We find that both kinase-activating and kinase-impaired CFC mutant alleles promote the equivalent developmental outcome when expressed during early development and that treatment of CFC-zebrafish embryos with inhibitors of the FGF-MAPK pathway can restore normal early development. Importantly, we find a developmental window in which treatment with a MEK inhibitor can restore the normal early development of the embryo, without the additional, unwanted developmental effects of the drug.

Capacitance of Ti 3C 2T x MXene in Ionic Liquid Electrolyte

DOE PAGES

Lin, Zifeng; Barbara, Daffos; Taberna, Pierre-Louis; ...

2016-04-14

Ti 3C 2T x MXene, a two-dimensional (2D) early transition metal carbide, has shown an extremely high volumetric capacitance in aqueous electrolytes, but in a narrow voltage window (less than 1.23 V). The utilization of MXene materials in ionic liquid electrolytes with a large voltage window has never been addressed. Here, we report the preparation of the Ti 3C 2T x MXene ionogel film by vacuum filtration for use as supercapacitor electrodes operating in 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI) neat ionic liquid electrolyte. Due to the disordered structure of the Ti 3C 2T x hydrogel film and a stable spacing after vacuummore » drying, achieved through ionic liquid electrolyte immersion of the Ti 3C 2T x hydrogel film, the Ti 3C 2T x surface became accessible to EMI + and TFSI - ions. A capacitance of 70 F g -1 together with a large voltage window of 3 V was obtained at a scan rate of 20 mV s -1 in neat EMI-TFSI electrolyte. The electrochemical signature indicates a capacitive behavior even at a high scan rate (500 mV s -1) and a high power performance. This work opens up the possibilities of using MXene materials with various ionic liquid electrolytes.« less

The water vapour continuum in near-infrared windows - Current understanding and prospects for its inclusion in spectroscopic databases

NASA Astrophysics Data System (ADS)

Shine, Keith P.; Campargue, Alain; Mondelain, Didier; McPheat, Robert A.; Ptashnik, Igor V.; Weidmann, Damien

2016-09-01

Spectroscopic catalogues, such as GEISA and HITRAN, do not yet include information on the water vapour continuum that pervades visible, infrared and microwave spectral regions. This is partly because, in some spectral regions, there are rather few laboratory measurements in conditions close to those in the Earth's atmosphere; hence understanding of the characteristics of the continuum absorption is still emerging. This is particularly so in the near-infrared and visible, where there has been renewed interest and activity in recent years. In this paper we present a critical review focusing on recent laboratory measurements in two near-infrared window regions (centred on 4700 and 6300 cm-1) and include reference to the window centred on 2600 cm-1 where more measurements have been reported. The rather few available measurements, have used Fourier transform spectroscopy (FTS), cavity ring down spectroscopy, optical-feedback - cavity enhanced laser spectroscopy and, in very narrow regions, calorimetric interferometry. These systems have different advantages and disadvantages. Fourier Transform Spectroscopy can measure the continuum across both these and neighbouring windows; by contrast, the cavity laser techniques are limited to fewer wavenumbers, but have a much higher inherent sensitivity. The available results present a diverse view of the characteristics of continuum absorption, with differences in continuum strength exceeding a factor of 10 in the cores of these windows. In individual windows, the temperature dependence of the water vapour self-continuum differs significantly in the few sets of measurements that allow an analysis. The available data also indicate that the temperature dependence differs significantly between different near-infrared windows. These pioneering measurements provide an impetus for further measurements. Improvements and/or extensions in existing techniques would aid progress to a full characterisation of the continuum - as an example, we report pilot measurements of the water vapour self-continuum using a supercontinuum laser source coupled to an FTS. Such improvements, as well as additional measurements and analyses in other laboratories, would enable the inclusion of the water vapour continuum in future spectroscopic databases, and therefore allow for a more reliable forward modelling of the radiative properties of the atmosphere. It would also allow a more confident assessment of different theoretical descriptions of the underlying cause or causes of continuum absorption.

Do mitochondria play a role in remodelling lace plant leaves during programmed cell death?

PubMed Central

2011-01-01

Background Programmed cell death (PCD) is the regulated death of cells within an organism. The lace plant (Aponogeton madagascariensis) produces perforations in its leaves through PCD. The leaves of the plant consist of a latticework of longitudinal and transverse veins enclosing areoles. PCD occurs in the cells at the center of these areoles and progresses outwards, stopping approximately five cells from the vasculature. The role of mitochondria during PCD has been recognized in animals; however, it has been less studied during PCD in plants. Results The following paper elucidates the role of mitochondrial dynamics during developmentally regulated PCD in vivo in A. madagascariensis. A single areole within a window stage leaf (PCD is occurring) was divided into three areas based on the progression of PCD; cells that will not undergo PCD (NPCD), cells in early stages of PCD (EPCD), and cells in late stages of PCD (LPCD). Window stage leaves were stained with the mitochondrial dye MitoTracker Red CMXRos and examined. Mitochondrial dynamics were delineated into four categories (M1-M4) based on characteristics including distribution, motility, and membrane potential (ΔΨm). A TUNEL assay showed fragmented nDNA in a gradient over these mitochondrial stages. Chloroplasts and transvacuolar strands were also examined using live cell imaging. The possible importance of mitochondrial permeability transition pore (PTP) formation during PCD was indirectly examined via in vivo cyclosporine A (CsA) treatment. This treatment resulted in lace plant leaves with a significantly lower number of perforations compared to controls, and that displayed mitochondrial dynamics similar to that of non-PCD cells. Conclusions Results depicted mitochondrial dynamics in vivo as PCD progresses within the lace plant, and highlight the correlation of this organelle with other organelles during developmental PCD. To the best of our knowledge, this is the first report of mitochondria and chloroplasts moving on transvacuolar strands to form a ring structure surrounding the nucleus during developmental PCD. Also, for the first time, we have shown the feasibility for the use of CsA in a whole plant system. Overall, our findings implicate the mitochondria as playing a critical and early role in developmentally regulated PCD in the lace plant. PMID:21645374

Transient inhibition of the ERK pathway prevents cerebellar developmental defects and improves long-term motor functions in murine models of neurofibromatosis type 1

PubMed Central

Kim, Edward; Wang, Yuan; Kim, Sun-Jung; Bornhorst, Miriam; Jecrois, Emmanuelle S; Anthony, Todd E; Wang, Chenran; Li, Yi E; Guan, Jun-Lin; Murphy, Geoffrey G; Zhu, Yuan

2014-01-01

Individuals with neurofibromatosis type 1 (NF1) frequently exhibit cognitive and motor impairments and characteristics of autism. The cerebellum plays a critical role in motor control, cognition, and social interaction, suggesting that cerebellar defects likely contribute to NF1-associated neurodevelopmental disorders. Here we show that Nf1 inactivation during early, but not late stages of cerebellar development, disrupts neuronal lamination, which is partially caused by overproduction of glia and subsequent disruption of the Bergmann glia (BG) scaffold. Specific Nf1 inactivation in glutamatergic neuronal precursors causes premature differentiation of granule cell (GC) precursors and ectopic production of unipolar brush cells (UBCs), indirectly disrupting neuronal migration. Transient MEK inhibition during a neonatal window prevents cerebellar developmental defects and improves long-term motor performance of Nf1-deficient mice. This study reveals essential roles of Nf1 in GC/UBC migration by generating correct numbers of glia and controlling GC/UBC fate-specification/differentiation, identifying a therapeutic prevention strategy for multiple NF1-associcated developmental abnormalities. DOI: http://dx.doi.org/10.7554/eLife.05151.001 PMID:25535838

Age at adoption from institutional care as a window into the lasting effects of early experiences

PubMed Central

Julian, Megan M.

2013-01-01

One of the major questions of human development is how early experience impacts the course of development years later. Children adopted from institutional care experience varying levels of deprivation in their early life followed by qualitatively better care in an adoptive home, providing a unique opportunity to study the lasting effects of early deprivation and its timing. The effects of age at adoption from institutional care are discussed for multiple domains of social and behavioral development within the context of several prominent developmental hypotheses about the effects of early deprivation (cumulative effects, experience-expectant developmental programming, and experience-adaptive developmental programming). Age at adoption effects are detected in a majority of studies, particularly when children experienced global deprivation and were assessed in adolescence. For most outcomes, institutionalization beyond a certain age is associated with a step-like increase in risk for lasting social and behavioral problems, with the step occurring at an earlier age for children who experienced more severe levels of deprivation. Findings are discussed in terms of their concordance and discordance with our current hypotheses, and speculative explanations for the findings are offered. PMID:23576122

Commonly dysregulated genes in murine APL cells

PubMed Central

Yuan, Wenlin; Payton, Jacqueline E.; Holt, Matthew S.; Link, Daniel C.; Watson, Mark A.; DiPersio, John F.; Ley, Timothy J.

2007-01-01

To identify genes that are commonly dysregulated in a murine model of acute promyelocytic leukemia (APL), we first defined gene expression patterns during normal murine myeloid development; serial gene expression profiling studies were performed with primary murine hematopoietic progenitors that were induced to undergo myeloid maturation in vitro with G-CSF. Many genes were reproducibly expressed in restricted developmental “windows,” suggesting a structured hierarchy of expression that is relevant for the induction of developmental fates and/or differentiated cell functions. We compared the normal myeloid developmental transcriptome with that of APL cells derived from mice expressing PML-RARα under control of the murine cathepsin G locus. While many promyelocyte-specific genes were highly expressed in all APL samples, 116 genes were reproducibly dysregulated in many independent APL samples, including Fos, Jun, Egr1, Tnf, and Vcam1. However, this set of commonly dysregulated genes was expressed normally in preleukemic, early myeloid cells from the same mouse model, suggesting that dysregulation occurs as a “downstream” event during disease progression. These studies suggest that the genetic events that lead to APL progression may converge on common pathways that are important for leukemia pathogenesis. PMID:17008535

Neurogenesis and Developmental Anesthetic Neurotoxicity

PubMed Central

Kang, Eunchai; Berg, Daniel A.; Furmanski, Orion; Jackson, William M.; Ryu, Yun Kyoung; Gray, Christy D.; Mintz, C. David

2017-01-01

The mechanism by which anesthetics might act on the developing brain in order to cause long term deficits remains incompletely understood. The hippocampus has been identified as a structure that is likely to be involved, as rodent models show numerous deficits in behavioral tasks of learning that are hippocampal-dependent. The hippocampus is an unusual structure in that it is the site of large amounts of neurogenesis postnatally, particularly in the first year of life in humans, and these newly generated neurons are critical to the function of this structure. Intriguingly, neurogenesis is a major developmental event that occurs during postulated windows of vulnerability to developmental anesthetic neurotoxicity across the different species in which it has been studied. In this review, we examine the evidence for anesthetic effects on neurogenesis in the early postnatal period and ask whether neurogenesis should be studied further as a putative mechanism of injury. Multiple anesthetics are considered, and both in vivo and in vitro work is presented. While there is abundant evidence that anesthetics act to suppress neurogenesis at several different phases, evidence of a causal link between these effects and any change in learning behavior remains elusive. PMID:27751818

Neurogenesis and developmental anesthetic neurotoxicity.

PubMed

Kang, Eunchai; Berg, Daniel A; Furmanski, Orion; Jackson, William M; Ryu, Yun Kyoung; Gray, Christy D; Mintz, C David

The mechanism by which anesthetics might act on the developing brain in order to cause long term deficits remains incompletely understood. The hippocampus has been identified as a structure that is likely to be involved, as rodent models show numerous deficits in behavioral tasks of learning that are hippocampal-dependent. The hippocampus is an unusual structure in that it is the site of large amounts of neurogenesis postnatally, particularly in the first year of life in humans, and these newly generated neurons are critical to the function of this structure. Intriguingly, neurogenesis is a major developmental event that occurs during postulated windows of vulnerability to developmental anesthetic neurotoxicity across the different species in which it has been studied. In this review, we examine the evidence for anesthetic effects on neurogenesis in the early postnatal period and ask whether neurogenesis should be studied further as a putative mechanism of injury. Multiple anesthetics are considered, and both in vivo and in vitro work is presented. While there is abundant evidence that anesthetics act to suppress neurogenesis at several different phases, evidence of a causal link between these effects and any change in learning behavior remains elusive. Copyright © 2016. Published by Elsevier Inc.

Present and future of developmental neuropsychopharmacology.

PubMed

Arango, Celso

2015-05-01

The field of child and adolescent psychiatry has always lagged behind adult psychiatry. With recent evidence that the vast majority of mental disorders, even when they emerge in adulthood, cause abnormal neurodevelopment and resultant emphasis on prevention and early intervention, there is a need to put child psychiatry at the top of the agenda in mental health research. This should also be the case for developmental neuropsychopharmacology. The target of drug discovery should shift toward a population younger than the one that is typically included in clinical trials. This is not only a matter of trying to replicate what has been found in individuals with mature brains; it is about searching for new strategies that address developing brains while the therapeutic window for their effect is still open. At present, major concerns in developmental psychopharmacology are over-prescription rates and use of psychotropic medications for conditions with a particularly underdeveloped evidence base, as well as adverse effects, especially potentially life-shortening cardiometabolic effects and suicidal ideation. The future of research in this area should focus on the use of drugs for primary and secondary prevention that would modify abnormal brain development. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

The Construct of the Multisensory Temporal Binding Window and its Dysregulation in Developmental Disabilities

PubMed Central

Wallace, Mark T.; Stevenson, Ryan A.

2014-01-01

Behavior, perception and cognition are strongly shaped by the synthesis of information across the different sensory modalities. Such multisensory integration often results in performance and perceptual benefits that reflect the additional information conferred by having cues from multiple senses providing redundant or complementary information. The spatial and temporal relationships of these cues provide powerful statistical information about how these cues should be integrated or “bound” in order to create a unified perceptual representation. Much recent work has examined the temporal factors that are integral in multisensory processing, with many focused on the construct of the multisensory temporal binding window – the epoch of time within which stimuli from different modalities is likely to be integrated and perceptually bound. Emerging evidence suggests that this temporal window is altered in a series of neurodevelopmental disorders, including autism, dyslexia and schizophrenia. In addition to their role in sensory processing, these deficits in multisensory temporal function may play an important role in the perceptual and cognitive weaknesses that characterize these clinical disorders. Within this context, focus on improving the acuity of multisensory temporal function may have important implications for the amelioration of the “higher-order” deficits that serve as the defining features of these disorders. PMID:25128432

Normal development of the tomato clownfish Amphiprion frenatus: live imaging and in situ hybridization analyses of mesodermal and neurectodermal development.

PubMed

Ghosh, J; Wilson, R W; Kudoh, T

2009-12-01

The normal embryonic development of the tomato clownfish Amphiprion frenatus was analysed using live imaging and by in situ hybridization for detection of mesodermal and neurectodermal development. Both morphology of live embryos and tissue-specific staining revealed significant differences in the gross developmental programme of A. frenatus compared with better-known teleost fish models, in particular, initiation of somitogenesis before complete epiboly, initiation of narrowing of the neurectoderm (neurulation) before somitogenesis, relatively early pigmentation of melanophores at the 10-15 somite stage and a distinctive pattern of melanophore distribution. These results suggest evolutionary adaptability of the teleost developmental programme. The ease of obtaining eggs, in vitro culture of the embryo, in situ staining analyses and these reported characteristics make A. frenatus a potentially important model marine fish species for studying embryonic development, physiology, ecology and evolution.

Behavioural evidence for separate mechanisms of audiovisual temporal binding as a function of leading sensory modality.

PubMed

Cecere, Roberto; Gross, Joachim; Thut, Gregor

2016-06-01

The ability to integrate auditory and visual information is critical for effective perception and interaction with the environment, and is thought to be abnormal in some clinical populations. Several studies have investigated the time window over which audiovisual events are integrated, also called the temporal binding window, and revealed asymmetries depending on the order of audiovisual input (i.e. the leading sense). When judging audiovisual simultaneity, the binding window appears narrower and non-malleable for auditory-leading stimulus pairs and wider and trainable for visual-leading pairs. Here we specifically examined the level of independence of binding mechanisms when auditory-before-visual vs. visual-before-auditory input is bound. Three groups of healthy participants practiced audiovisual simultaneity detection with feedback, selectively training on auditory-leading stimulus pairs (group 1), visual-leading stimulus pairs (group 2) or both (group 3). Subsequently, we tested for learning transfer (crossover) from trained stimulus pairs to non-trained pairs with opposite audiovisual input. Our data confirmed the known asymmetry in size and trainability for auditory-visual vs. visual-auditory binding windows. More importantly, practicing one type of audiovisual integration (e.g. auditory-visual) did not affect the other type (e.g. visual-auditory), even if trainable by within-condition practice. Together, these results provide crucial evidence that audiovisual temporal binding for auditory-leading vs. visual-leading stimulus pairs are independent, possibly tapping into different circuits for audiovisual integration due to engagement of different multisensory sampling mechanisms depending on leading sense. Our results have implications for informing the study of multisensory interactions in healthy participants and clinical populations with dysfunctional multisensory integration. © 2016 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Titan's Surface Composition from the Cassini Visual and Infrared Mapping Spectrometer (VIMS) Investigation

NASA Astrophysics Data System (ADS)

McCord, T. B.; Griffith, C. A.; Hansen, G. B.; Lunine, J. I.; Baines, K. H.; Brown, R. H.; Buratti, B.; Clark, R. N.; Cruikshank, D. P.; Filacchione, G.; Jaumann, R.; Hibbitts, C. A.; Sotine, C.; Cassini VIMS

2004-11-01

Titan, the largest satellite of Saturn, has a thick atmosphere containing methane with high altitude haze that obscures the surface except for windows in the methane absorption bands at some IR wavelengths where scattering also is reduced. Chemistry models of the atmosphere suggest deep deposits of organic liquids and solids (1). Groundbased telescopic observations of Titan's integral disk suggest the presence of water ice (2). The Cassini VIMS obtained spectra in the 0.35 to 5.1 μm range that include narrow windows in the methane spectrum near 1.6, 2.0, 2.8, and 5.0 μm where the surface might have been observed with spatial resolution up to about 100 x 200 km during the Saturn orbit insertion phase on June 30 2004. Surface albedo features seem to appear in these windows. We have analyzed Titan's spectra in an attempt to identity the surface material(s). The VIMS spectra were averaged for several pixels for each of six regions on Titan corresponding to apparent bright and dark surface features. The spectra were calibrated to I/F as seen by VIMS and then were analyzed using radiative transfer models to remove the effects of the atmosphere (2) to estimate surface I/F values. These were then compared with candidate material reflectance at each of the spectral windows. Preliminary analysis suggests that the average results will agree with previous groundbased data analyses (2) and there is the suggestion of differences in reflectance among the surface regions analyzed so far. This work was supported by the NASA Cassini Project. (1) Lunine et al., Science, 222, 1229, 1983. (2) Coustenis et al., Icarus 118, 87, 1995; Griffith et al., Science 300, 628, 2003.

Porous poly-ether ether ketone (PEEK) manufactured by a novel powder route using near-spherical salt bead porogens: characterisation and mechanical properties.

PubMed

Siddiq, Abdur R; Kennedy, Andrew R

2015-02-01

Porous PEEK structures with approximately 85% open porosity have been made using PEEK-OPTIMA® powder and a particulate leaching technique using porous, near-spherical, sodium chloride beads. A novel manufacturing approach is presented and compared with a traditional dry mixing method. Irrespective of the method used, the use of near-spherical beads with a fairly narrow size range results in uniform pore structures. However the integration, by tapping, of fine PEEK into a pre-existing network salt beads, followed by compaction and "sintering", produces porous structures with excellent repeatability and homogeneity of density; more uniform pore and strut sizes; an improved and predictable level of connectivity via the formation of "windows" between the cells; faster salt removal rates and lower levels of residual salt. Although tapped samples show a compressive yield stress >1 MPa and stiffness >30 MPa for samples with 84% porosity, the presence of windows in the cell walls means that tapped structures show lower strengths and lower stiffnesses than equivalent structures made by mixing. Copyright © 2014 Elsevier B.V. All rights reserved.

Reference measurements on a Francis model turbine with 2D Laser-Doppler-Anemometry

NASA Astrophysics Data System (ADS)

Frey, A.; Kirschner, O.; Riedelbauch, S.; Jester-Zuerker, R.; Jung, A.

2016-11-01

To validate the investigations of a high-resolution CFD simulation of a Francis turbine, measurements with 2D Laser-Doppler-Anemometry are carried out. The turbine is operated in part load, where a rotating vortex rope occurs. To validate both, mean velocities and velocity fluctuations, the measurements are classified relative to the vortex rope position. Several acrylic glass windows are installed in the turbine walls such as upstream of the spiral case inlet, in the vaneless space and in the draft tube. The current investigation is focused on a measurement plane below the runner. 2D velocity components are measured on this whole plane by measuring several narrow spaced radial lines. To avoid optical refraction of the laser beam a plan parallel window is inserted in the cone wall. The laser probe is positioned with a 2D traverse system consisting of a circumferential rail and a radial aligned linear traverse. The velocity data are synchronized with the rotational frequency of the rotating vortex rope. The results of one measurement line show the dependency of the axial and circumferential velocities on the vortex rope position.

Seismpol_ a visual-basic computer program for interactive and automatic earthquake waveform analysis

NASA Astrophysics Data System (ADS)

Patanè, Domenico; Ferrari, Ferruccio

1997-11-01

A Microsoft Visual-Basic computer program for waveform analysis of seismic signals is presented. The program combines interactive and automatic processing of digital signals using data recorded by three-component seismic stations. The analysis procedure can be used in either an interactive earthquake analysis or an automatic on-line processing of seismic recordings. The algorithm works in the time domain using the Covariance Matrix Decomposition method (CMD), so that polarization characteristics may be computed continuously in real time and seismic phases can be identified and discriminated. Visual inspection of the particle motion in hortogonal planes of projection (hodograms) reduces the danger of misinterpretation derived from the application of the polarization filter. The choice of time window and frequency intervals improves the quality of the extracted polarization information. In fact, the program uses a band-pass Butterworth filter to process the signals in the frequency domain by analysis of a selected signal window into a series of narrow frequency bands. Significant results supported by well defined polarizations and source azimuth estimates for P and S phases are also obtained for short-period seismic events (local microearthquakes).

Observational program options and system requirements for the search for extraterrestrial intelligence /SETI/

NASA Technical Reports Server (NTRS)

Billingham, J.; Wolfe, J. H.; Edelson, R. E.; Gulkis, S.; Sadin, S. R.

1978-01-01

The possibility that intelligent life may be widespread in the universe is now being investigated. A formula for estimating the number of coexisting communicative civilizations has been developed by Drake. A good way of conducting a search for extraterrestrial intelligence (SETI) is to examine the microwave window of the electromagnetic spectrum for narrow-band signals which such civilizations may be transmitting. Two specific search strategies are described. Both employ existing antennas equipped with sophisticated multichannel spectrum analyzers and pattern recognition devices. The Ames Research Center proposal is a high sensitivity, high-resolution search of nearby promising stars and selected sky areas in the 'water hole' (1400-1727 MHz). The Jet Propulsion Laboratory proposal is for a survey of most of the sky over a significant portion of the free-space microwave window at lower sensitivities and resolutions. The approaches are complementary and both are being pursued. The consummation of these programs could achieve one of the most profound discoveries in the history of human civilization, or at least will show the way to future efforts.

Broadband laser ranging precision and accuracy experiments with PDV benchmarking

NASA Astrophysics Data System (ADS)

Catenacci, Jared; Daykin, Ed; Howard, Marylesa; Lalone, Brandon; Miller, Kirk

2017-06-01

Broadband laser ranging (BLR) is a developmental diagnostic designed to measure the precise position of surfaces and particle clouds moving at velocities of several kilometers per second. Recent single stage gas gun experiments were conducted to quantify the precision and accuracy possible with a typical BLR system. For these experiments, the position of a mirrored projectile is measured relative to the location of a stationary optical flat (uncoated window) mounted within the gun catch tank. Projectile velocity is constrained to one-dimensional motion within the gun barrel. A collimating probe is aligned to be orthogonal to both the target window and the mirrored impactor surface. The probe is used to simultaneously measure the position and velocity with a BLR and conventional Photonic Doppler Velocimetry (PDV) system. Since there is a negligible lateral component to the target velocity, coupled with strong signal returns from a mirrored surface, integrating the PDV measurement provides a high fidelity distance measurement reference to which the BLR measurement may be compared.

Optimized ex-ovo culturing of chick embryos to advanced stages of development.

PubMed

Cloney, Kellie; Franz-Odendaal, Tamara Anne

2015-01-24

Research in anatomy, embryology, and developmental biology has largely relied on the use of model organisms. In order to study development in live embryos model organisms, such as the chicken, are often used. The chicken is an excellent model organism due to its low cost and minimal maintenance, however they present observational challenges because they are enclosed in an opaque eggshell. In order to properly view the embryo as it develops, the shell must be windowed or removed. Both windowing and ex ovo techniques have been developed to assist researchers in the study of embryonic development. However, each of the methods has limitations and challenges. Here, we present a simple, optimized ex ovo culture technique for chicken embryos that enables the observation of embryonic development from stage HH 19 into late stages of development (HH 40), when many organs have developed. This technique is easy to adopt in both undergraduate classes and more advanced research laboratories where embryo manipulations are conducted.

War's enduring effects on the development of egalitarian motivations and in-group biases.

PubMed

Bauer, Michal; Cassar, Alessandra; Chytilová, Julie; Henrich, Joseph

2014-01-01

In suggesting that new nations often coalesce in the decades following war, historians have posed an important psychological question: Does the experience of war generate an enduring elevation in people's egalitarian motivations toward their in-group? We administered social-choice tasks to more than 1,000 children and adults differentially affected by wars in the Republic of Georgia and Sierra Leone. We found that greater exposure to war created a lasting increase in people's egalitarian motivations toward their in-group, but not their out-groups, during a developmental window starting in middle childhood (around 7 years of age) and ending in early adulthood (around 20 years of age). Outside this window, war had no measurable impact on social motivations in young children and had only muted effects on the motivations of older adults. These "war effects" are broadly consistent with predictions from evolutionary approaches that emphasize the importance of group cooperation in defending against external threats, though they also highlight key areas in need of greater theoretical development.

High resolution time-to-space conversion of sub-picosecond pulses at 1.55µm by non-degenerate SFG in PPLN crystal.

PubMed

Shayovitz, Dror; Herrmann, Harald; Sohler, Wolfgang; Ricken, Raimund; Silberhorn, Christine; Marom, Dan M

2012-11-19

We demonstrate high resolution and increased efficiency background-free time-to-space conversion using spectrally resolved non-degenerate and collinear SFG in a bulk PPLN crystal. A serial-to-parallel resolution factor of 95 and a time window of 42 ps were achieved. A 60-fold increase in conversion efficiency slope compared with our previous work using a BBO crystal [D. Shayovitz and D. M. Marom, Opt. Lett. 36, 1957 (2011)] was recorded. Finally the measured 40 GHz narrow linewidth of the output SFG signal implies the possibility to extract phase information by employing coherent detection techniques.

Time-to-space mapping of a continuous light wave with picosecond time resolution based on an electrooptic beam deflection.

PubMed

Hisatake, S; Kobayashi, T

2006-12-25

We demonstrate a time-to-space mapping of an optical signal with a picosecond time resolution based on an electrooptic beam deflection. A time axis of the optical signal is mapped into a spatial replica by the deflection. We theoretically derive a minimum time resolution of the time-to-space mapping and confirm it experimentally on the basis of the pulse width of the optical pulses picked out from the deflected beam through a narrow slit which acts as a temporal window. We have achieved the minimum time resolution of 1.6+/-0.2 ps.

The Disk-Jet Connection in Radio-Loud AGN: The X-Ray Perspective

NASA Technical Reports Server (NTRS)

Sambruna, Rita

2008-01-01

Unification schemes assume that radio-loud active galactic nuclei (AGN) contain an accretion disk and a relativistic jet perpendicular to the disk, and an obscuring molecular torus. The jet dominance decreases with larger viewing angles from blazars to Broad-Line and Narrow-Line Radio Galaxies. A fundamental question is how accretion and ejecta are related. The X-rays provide a convenient window to study these issues, as they originate in the innermost nuclear regions and penetrate large obscuring columns. I review the data, using observations by Chandra but also from other currently operating high-energy experiments. Synergy with the upcoming GLAST mission will also be highlighted.

Problems and pitfalls in cardiac drug therapy.

PubMed

Stone, S M; Rai, N; Nei, J

2001-01-01

Medical errors in the care of patients may account for 44,000 to 98,000 deaths per year, and 7,000 deaths per year are attributed to medication errors alone. Increasing awareness among health care providers of potential errors is a critical step toward improving the safety of medical care. Because today's medications are increasingly complex, approved at an accelerated rate, and often have a narrow therapeutic window with only a small margin of safety, patient and provider education is critical in assuring optimal therapeutic outcomes. Providers can use electronic resources such as Web sites to keep informed on drug-drug, drug-food, and drug-nutritional supplements interactions.

Two-step ion-exchange chromatographic purification combined with reversed-phase chromatography to isolate C-peptide for mass spectrometric analysis.

PubMed

Kabytaev, Kuanysh; Durairaj, Anita; Shin, Dmitriy; Rohlfing, Curt L; Connolly, Shawn; Little, Randie R; Stoyanov, Alexander V

2016-02-01

A liquid chromatography with mass spectrometry on-line platform that includes the orthogonal techniques of ion exchange and reversed phase chromatography is applied for C-peptide analysis. Additional improvement is achieved by the subsequent application of cation- and anion-exchange purification steps that allow for isolating components that have their isoelectric points in a narrow pH range before final reversed-phase mass spectrometry analysis. The utility of this approach for isolating fractions in the desired "pI window" for profiling complex mixtures is discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laser-Based Production of Metallic Conducting Paths

NASA Astrophysics Data System (ADS)

Vedder, Christian; Stollenwerk, Jochen; Wissenbach, Konrad; Pirch, Norbert

For numerous devices such as OLEDs, solar cells or heated windows conducting paths are needed for collecting or distributing electricity on poorly or non-conducting surfaces. With established techniques the metallic paths can only be produced with a great deal of effort, incurring high costs for plant, equipment and energy. A new laser based process to manufacture conducting paths allows for writing narrow paths (down to 35 μm width) of Al, Cu, Ag or similar materials onto flat surfaces of glass (plain or coated with ITO) and silicon wafers by melting and vaporizing a metal foil through optical energy at high speeds of up to 2.5 m/s.

An explicit approach to detecting and characterizing submersed aquatic vegetation using a single-beam digital echosounder

NASA Astrophysics Data System (ADS)

Sabol, Bruce M.

2005-09-01

There has been a longstanding need for an objective and cost-effective technique to detect, characterize, and quantify submersed aquatic vegetation at spatial scales between direct physical sampling and remote aerial-based imaging. Acoustic-based approaches for doing so are reviewed and an explicit approach, using a narrow, single-beam echosounder, is described in detail. This heuristic algorithm is based on the spatial distribution of a thresholded signal generated from a high-frequency, narrow-beam echosounder operated in a vertical orientation from a survey boat. The physical basis, rationale, and implementation of this algorithm are described, and data documenting performance are presented. Using this technique, it is possible to generate orders of magnitude more data than would be available using previous techniques with a comparable level of effort. Thus, new analysis and interpretation approaches are called for which can make full use of these data. Several analyses' examples are shown for environmental effects application studies. Current operational window and performance limitations are identified and thoughts on potential processing approaches to improve performance are discussed.

The Role of Maternal Nutrition During the Periconceptional Period and Its Effect on Offspring Phenotype.

PubMed

Fleming, Tom P; Eckert, Judith J; Denisenko, Oleg

2017-01-01

The early preimplantation embryo has been rigorously studied for decades to understand inherent reproductive and developmental mechanisms driving its morphogenesis from before fertilisation through to and beyond implantation. Recent research has demonstrated that this short developmental window is also critical for the embryo's interaction with external, maternal factors, particularly nutritional status. Here, maternal dietary quality has been shown to alter the pattern of development in an enduring way that can influence health throughout the lifetime. Thus, using mouse models, maternal protein restriction exclusively during the preimplantation period with normal nutrition thereafter is sufficient to cause adverse cardiometabolic and neurological outcomes in adult offspring. Evidence for similar effects whereby environmental factors during the periconceptional window can programme postnatal disease risk can be found in human and large animal models and also in response to in vitro conditions such as assisted conception and related infertility treatments. In this review, using mouse malnutrition models, we evaluate the step-by-step mechanisms that lead from maternal poor diet consumption though to offspring disease. We consider how adverse programming within the embryo may be induced, what nutrient factors and signalling pathways may be involved, and how these cues act to change the embryo in distinct ways across placental and foetal lineage paths, leading especially to changes in the growth trajectory which in turn associate with later disease risk. These mechanisms straddle epigenetic, molecular, cellular and physiological levels of biology and suggest, for health outcomes, preimplantation development to be the most important time in our lives.

Developmental evidence for obstetric adaptation of the human female pelvis.

PubMed

Huseynov, Alik; Zollikofer, Christoph P E; Coudyzer, Walter; Gascho, Dominic; Kellenberger, Christian; Hinzpeter, Ricarda; Ponce de León, Marcia S

2016-05-10

The bony pelvis of adult humans exhibits marked sexual dimorphism, which is traditionally interpreted in the framework of the "obstetrical dilemma" hypothesis: Giving birth to large-brained/large-bodied babies requires a wide pelvis, whereas efficient bipedal locomotion requires a narrow pelvis. This hypothesis has been challenged recently on biomechanical, metabolic, and biocultural grounds, so that it remains unclear which factors are responsible for sex-specific differences in adult pelvic morphology. Here we address this issue from a developmental perspective. We use methods of biomedical imaging and geometric morphometrics to analyze changes in pelvic morphology from late fetal stages to adulthood in a known-age/known-sex forensic/clinical sample. Results show that, until puberty, female and male pelves exhibit only moderate sexual dimorphism and follow largely similar developmental trajectories. With the onset of puberty, however, the female trajectory diverges substantially from the common course, resulting in rapid expansion of obstetrically relevant pelvic dimensions up to the age of 25-30 y. From 40 y onward females resume a mode of pelvic development similar to males, resulting in significant reduction of obstetric dimensions. This complex developmental trajectory is likely linked to the pubertal rise and premenopausal fall of estradiol levels and results in the obstetrically most adequate pelvic morphology during the time of maximum female fertility. The evidence that hormones mediate female pelvic development and morphology supports the view that solutions of the obstetrical dilemma depend not only on selection and adaptation but also on developmental plasticity as a response to ecological/nutritional factors during a female's lifetime.

Developmental evidence for obstetric adaptation of the human female pelvis

PubMed Central

Huseynov, Alik; Zollikofer, Christoph P. E.; Coudyzer, Walter; Gascho, Dominic; Kellenberger, Christian; Hinzpeter, Ricarda; Ponce de León, Marcia S.

2016-01-01

The bony pelvis of adult humans exhibits marked sexual dimorphism, which is traditionally interpreted in the framework of the “obstetrical dilemma” hypothesis: Giving birth to large-brained/large-bodied babies requires a wide pelvis, whereas efficient bipedal locomotion requires a narrow pelvis. This hypothesis has been challenged recently on biomechanical, metabolic, and biocultural grounds, so that it remains unclear which factors are responsible for sex-specific differences in adult pelvic morphology. Here we address this issue from a developmental perspective. We use methods of biomedical imaging and geometric morphometrics to analyze changes in pelvic morphology from late fetal stages to adulthood in a known-age/known-sex forensic/clinical sample. Results show that, until puberty, female and male pelves exhibit only moderate sexual dimorphism and follow largely similar developmental trajectories. With the onset of puberty, however, the female trajectory diverges substantially from the common course, resulting in rapid expansion of obstetrically relevant pelvic dimensions up to the age of 25–30 y. From 40 y onward females resume a mode of pelvic development similar to males, resulting in significant reduction of obstetric dimensions. This complex developmental trajectory is likely linked to the pubertal rise and premenopausal fall of estradiol levels and results in the obstetrically most adequate pelvic morphology during the time of maximum female fertility. The evidence that hormones mediate female pelvic development and morphology supports the view that solutions of the obstetrical dilemma depend not only on selection and adaptation but also on developmental plasticity as a response to ecological/nutritional factors during a female’s lifetime. PMID:27114515

Developmental plasticity of mating calls enables acoustic communication in diverse environments

PubMed Central

Beckers, Oliver M; Schul, Johannes

2008-01-01

Male calls of the katydid Neoconocephalus triops exhibit substantial developmental plasticity in two parameters: (i) calls of winter males are continuous and lack the verse structure of summer calls and (ii) at equal temperatures, summer males produce calls with a substantially higher pulse rate than winter males. We raised female N. triops under conditions that reliably induced either summer or winter phenotype and tested their preferences for the call parameters that differ between summer and winter males. Neither generation was selective for the presence of verses, but females had strong preferences for pulse rates: only a narrow range of pulse rates was attractive. The attractive ranges did not differ between summer and winter females. Both male pulse rate and female preference for pulse rate changed with ambient temperature, but female preference changed more than the male calls. As a result, the summer call was attractive only at 25°C, whereas the slower winter call was attractive only at 20°C. Thus, developmental plasticity of male calls compensates for differences in temperature dependency between calls and preferences and enables the communication system to function in heterogeneous environments. The potential role of call plasticity during the invasion of new habitats is discussed. PMID:18302998

Spirituality as a Positive Youth Development Construct: A Conceptual Review

PubMed Central

Shek, Daniel T. L.

2012-01-01

The concept of spirituality as a positive youth development construct is reviewed in this paper. Both broad and narrow definitions of spirituality are examined and a working definition of spirituality is proposed. Regarding theories of spirituality, different models pertinent to spiritual development and the relationship between spirituality and positive youth development are highlighted. Different ecological factors, particularly family and peer influences, were found to influence spirituality. Research on the influence of spirituality on adolescent developmental outcomes is examined. Finally, ways to promote adolescent spirituality are discussed. PMID:22654611

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furforo, L.; Rittler, M.; Slavutsky, I.R.

We report on a girl with developmental delay, macrocephaly, facial asymmetry, small downturned palpebral fissures, high and narrow palate, micrognathia, short neck, a heart defect, and unilateral renal agenesis. Cytogenetic analysis showed a proximal tandem duplication of the long arm of chromosome one (1q12{r_arrow}q21.3). This abnormality was suggested by G-and C-banding but it was specifically characterized by fluorescent in situ hybridization (FISH). Clinical findings in our patient are compared with those of the literature in an attempt to delineate the phenotype in patients with proximal 1q duplication. 12 refs., 4 figs., 1 tab.

Evaluation of SNS Beamline Shielding Configurations using MCNPX Accelerated by ADVANTG

DOE Office of Scientific and Technical Information (OSTI.GOV)

Risner, Joel M; Johnson, Seth R.; Remec, Igor

2015-01-01

Shielding analyses for the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory pose significant computational challenges, including highly anisotropic high-energy sources, a combination of deep penetration shielding and an unshielded beamline, and a desire to obtain well-converged nearly global solutions for mapping of predicted radiation fields. The majority of these analyses have been performed using MCNPX with manually generated variance reduction parameters (source biasing and cell-based splitting and Russian roulette) that were largely based on the analyst's insight into the problem specifics. Development of the variance reduction parameters required extensive analyst time, and was often tailored to specific portionsmore » of the model phase space. We previously applied a developmental version of the ADVANTG code to an SNS beamline study to perform a hybrid deterministic/Monte Carlo analysis and showed that we could obtain nearly global Monte Carlo solutions with essentially uniform relative errors for mesh tallies that cover extensive portions of the model with typical voxel spacing of a few centimeters. The use of weight window maps and consistent biased sources produced using the FW-CADIS methodology in ADVANTG allowed us to obtain these solutions using substantially less computer time than the previous cell-based splitting approach. While those results were promising, the process of using the developmental version of ADVANTG was somewhat laborious, requiring user-developed Python scripts to drive much of the analysis sequence. In addition, limitations imposed by the size of weight-window files in MCNPX necessitated the use of relatively coarse spatial and energy discretization for the deterministic Denovo calculations that we used to generate the variance reduction parameters. We recently applied the production version of ADVANTG to this beamline analysis, which substantially streamlined the analysis process. We also tested importance function collapsing (in space and energy) capabilities in ADVANTG. These changes, along with the support for parallel Denovo calculations using the current version of ADVANTG, give us the capability to improve the fidelity of the deterministic portion of the hybrid analysis sequence, obtain improved weight-window maps, and reduce both the analyst and computational time required for the analysis process.« less

Analysis of the Poisson-Nernst-Planck equation in a ball for modeling the Voltage-Current relation in neurobiological microdomains

NASA Astrophysics Data System (ADS)

Cartailler, J.; Schuss, Z.; Holcman, D.

2017-01-01

The electro-diffusion of ions is often described by the Poisson-Nernst-Planck (PNP) equations, which couple nonlinearly the charge concentration and the electric potential. This model is used, among others, to describe the motion of ions in neuronal micro-compartments. It remains at this time an open question how to determine the relaxation and the steady state distribution of voltage when an initial charge of ions is injected into a domain bounded by an impermeable dielectric membrane. The purpose of this paper is to construct an asymptotic approximation to the solution of the stationary PNP equations in a d-dimensional ball (d = 1 , 2 , 3) in the limit of large total charge. In this geometry the PNP system reduces to the Liouville-Gelfand-Bratú (LGB) equation, with the difference that the boundary condition is Neumann, not Dirichlet, and there is a minus sign in the exponent of the exponential term. The entire boundary is impermeable to ions and the electric field satisfies the compatibility condition of Poisson's equation. These differences replace attraction by repulsion in the LGB equation, thus completely changing the solution. We find that the voltage is maximal in the center and decreases toward the boundary. We also find that the potential drop between the center and the surface increases logarithmically in the total number of charges and not linearly, as in classical capacitance theory. This logarithmic singularity is obtained for d = 3 from an asymptotic argument and cannot be derived from the analysis of the phase portrait. These results are used to derive the relation between the outward current and the voltage in a dendritic spine, which is idealized as a dielectric sphere connected smoothly to the nerve axon by a narrow neck. This is a fundamental microdomain involved in neuronal communication. We compute the escape rate of an ion from the steady density in a ball, which models a neuronal spine head, to a small absorbing window in the sphere. We predict that the current is defined by the narrow neck that is connected to the sphere by a small absorbing window, as suggested by the narrow escape theory, while voltage is controlled by the PNP equations independently of the neck.

Possibility of Recombination Gain Increase in CV Ions at 4.0 nm Via Coherence

NASA Astrophysics Data System (ADS)

Luo, Y.; Morozov, A.; Gordon, D.; Sprangle, P.; Svidzinsky, A.; Xia, H.; Scully, M.; Suckewer, S.

This paper is about the recent experimental results on amplification of the CV line in the "water window" at 4.03 nm from resonance transition to the ground level of He-like ions in recombination scheme. The indication of the amplification of the CV line has been observed when an elongated narrow plasma channel was created, where high intensity 100 fs beams, optimal for creating CV ions in high density plasma, was propagated up to 0.5-0.6 mm. Without channeling the effective plasma length was much shorter and there was no indication of amplification.The large interest in gain generation in He-like ions in the transition to ground state is due to the possibility of applying a recently developed theory of Lasing Without Inversion (LWI) in XUV and X-ray regions to largely increase the gain for such transitions. The presented results of the indication of CV line amplifications are being discussed from the point of view of using LWI as a superradiance gain increase, hence to construct a very compact soft X-ray laser in the "water window".The last part of the paper is related to the application of the ultra-intensive fs plasma laser, which is currently in the process of development by using stimulated Raman backscattering (SRBS) to create a plasma amplifier and compressor, as the pump for compact laser operating in the "water window" and also at shorter wavelengths.

Obtaining a Low and Wide Atomic Layer Deposition Window (150-275 °C) for In2 O3 Films Using an InIII Amidinate and H2 O.

PubMed

Kim, Sang Bok; Jayaraman, Ashwin; Chua, Danny; Davis, Luke M; Zheng, Shao-Liang; Zhao, Xizhu; Lee, Sunghwan; Gordon, Roy G

2018-06-05

Indium oxide is a major component of many technologically important thin films, most notably the transparent conductor indium tin oxide (ITO). Despite being pyrophoric, homoleptic indium(III) alkyls do not allow atomic layer deposition (ALD) of In 2 O 3 using water as a co-precursor at substrate temperatures below 200 °C. Several alternative indium sources have been developed, but none allows ALD at lower temperatures except in the presence of oxidants such as O 2 or O 3 , which are not compatible with some substrates or alloying processes. We have synthesized a new indium precursor, tris(N,N'-diisopropylformamidinato)indium(III), compound 1, which allows ALD of pure, carbon-free In 2 O 3 films using H 2 O as the only co-reactant, on substrates in the temperature range 150-275 °C. In contrast, replacing just the H of the anionic iPrNC(H)NiPr ligand with a methyl group (affording the known tris(N,N'-diisopropylacetamidinato)indium(III), compound 2) results in a considerably higher and narrower ALD window in the analogous reaction with H 2 O (225-300 °C). Kinetic studies demonstrate that a higher rate of surface reactions in both parts of the ALD cycle gives rise to this difference in the ALD windows. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Defect window analysis by using SEM-contour based shape quantifying method for sub-20nm node production

NASA Astrophysics Data System (ADS)

Hibino, Daisuke; Hsu, Mingyi; Shindo, Hiroyuki; Izawa, Masayuki; Enomoto, Yuji; Lin, J. F.; Hu, J. R.

2013-04-01

The impact on yield loss due to systematic defect which remains after Optical Proximity Correction (OPC) modeling has increased, and achieving an acceptable yield has become more difficult in the leading technology beyond 20 nm node production. Furthermore Process-Window has become narrow because of the complexity of IC design and less process margin. In the past, the systematic defects have been inspected by human-eyes. However the judgment by human-eyes is sometime unstable and not accurate. Moreover an enormous amount of time and labor will have to be expended on the one-by-one judgment for several thousands of hot-spot defects. In order to overcome these difficulties and improve the yield and manufacturability, the automated system, which can quantify the shape difference with high accuracy and speed, is needed. Inspection points could be increased for getting higher yield, if the automated system achieves our goal. Defect Window Analysis (DWA) system by using high-precision-contour extraction from SEM image on real silicon and quantifying method which can calculate the difference between defect pattern and non-defect pattern automatically, which was developed by Hitachi High-Technologies, has been applied to the defect judgment instead of the judgment by human-eyes. The DWA result which describes process behavior might be feedback to design or OPC or mask. This new methodology and evaluation results will be presented in detail in this paper.

Improved photovoltaic properties of ZnTeO-based intermediate band solar cells

NASA Astrophysics Data System (ADS)

Tanaka, Tooru; Saito, Katsuhiko; Guo, Qixin; Yu, Kin Man; Walukiewicz, Wladek

2018-02-01

Highly mismatched ZnTe1-xOx (ZnTeO) alloy is one of the potential candidates for an absorber material in a bulk intermediate band solar cell (IBSC) because a narrow, O-derived intermediate band IB (E-) is formed well below the conduction band CB (E+) edge of the ZnTe. We have previously demonstrated the generation of photocurrent induced by two-step photon absorption (TSPA) in ZnTeO IBSCs using n-ZnO window layer. However, because of the large conduction band offset (CBO) between ZnTe and ZnO, only a small open circuit voltage (Voc) was observed in this structure. Here, we report our recent progress on the development of ZnTeO IBSCs with n-ZnS window layer. ZnS has a large direct band gap of 3.7 eV with an electron affinity of 3.9 eV that can realize a smaller CBO with ZnTe. We have grown n-type ZnS thin films on ZnTe substrates by molecular beam epitaxy (MBE), and demonstrated ZnTe solar cells and ZnTeO IBSCs using n-ZnS window layer with an improved VOC. Especially, a n-ZnS/i-ZnTe/p-ZnTe solar cell showed an improved Voc of 0.77 V, a large short-circuit current density of 6.7 mA/cm2 with a fill factor of 0.60, yielding the power conversion efficiency of 3.1 %, under 1 sun illumination.

Psychosocially influenced cancer: diverse early-life stress experiences and links to breast cancer.

PubMed

Schuler, Linda A; Auger, Anthony P

2010-11-01

This perspective on Boyd et al. (beginning on page 1398 in this issue of the journal) discusses recent published research examining the interplay between social stress and breast cancer. Cross-disciplinary studies using genetically defined mouse models and established neonatal and peripubertal paradigms of social stress are illuminating biological programming by diverse early-life experiences for the risk of breast cancer. Understanding the mechanisms underlying this programming can lead to the identification of risk factors and sensitive developmental windows, enabling improved prevention and treatment strategies for this devastating disease. ©2010 AACR.

Early structural and functional plasticity alterations in a susceptibility period of DYT1 dystonia mouse striatum

PubMed Central

Maltese, Marta; Stanic, Jennifer; Tassone, Annalisa; Sciamanna, Giuseppe; Ponterio, Giulia; Vanni, Valentina; Martella, Giuseppina; Imbriani, Paola; Bonsi, Paola; Mercuri, Nicola Biagio

2018-01-01

The onset of abnormal movements in DYT1 dystonia is between childhood and adolescence, although it is unclear why clinical manifestations appear during this developmental period. Plasticity at corticostriatal synapses is critically involved in motor memory. In the Tor1a+/Δgag DYT1 dystonia mouse model, long-term potentiation (LTP) appeared prematurely in a critical developmental window in striatal spiny neurons (SPNs), while long-term depression (LTD) was never recorded. Analysis of dendritic spines showed an increase of both spine width and mature mushroom spines in Tor1a+/Δgag neurons, paralleled by an enhanced AMPA receptor (AMPAR) accumulation. BDNF regulates AMPAR expression during development. Accordingly, both proBDNF and BDNF levels were significantly higher in Tor1a+/Δgag mice. Consistently, antagonism of BDNF rescued synaptic plasticity deficits and AMPA currents. Our findings demonstrate that early loss of functional and structural synaptic homeostasis represents a unique endophenotypic trait during striatal maturation, promoting the appearance of clinical manifestations in mutation carriers. PMID:29504938

A systematic evaluation of the potential effects of trichloroethylene exposure on cardiac development.

PubMed

Makris, Susan L; Scott, Cheryl Siegel; Fox, John; Knudsen, Thomas B; Hotchkiss, Andrew K; Arzuaga, Xabier; Euling, Susan Y; Powers, Christina M; Jinot, Jennifer; Hogan, Karen A; Abbott, Barbara D; Hunter, E Sidney; Narotsky, Michael G

2016-10-01

The 2011 EPA trichloroethylene (TCE) IRIS assessment, used developmental cardiac defects from a controversial drinking water study in rats (Johnson et al. [51]), along with several other studies/endpoints to derive reference values. An updated literature search of TCE-related developmental cardiac defects was conducted. Study quality, strengths, and limitations were assessed. A putative adverse outcome pathway (AOP) construct was developed to explore key events for the most commonly observed cardiac dysmorphologies, particularly those involved with epithelial-mesenchymal transition (EMT) of endothelial origin (EndMT); several candidate pathways were identified. A hypothesis-driven weight-of-evidence analysis of epidemiological, toxicological, in vitro, in ovo, and mechanistic/AOP data concluded that TCE has the potential to cause cardiac defects in humans when exposure occurs at sufficient doses during a sensitive window of fetal development. The study by Johnson et al. [51] was reaffirmed as suitable for hazard characterization and reference value derivation, though acknowledging study limitations and uncertainties. Published by Elsevier Inc.

Why Do Anxious Children Become Depressed Teenagers?: The Role of Social Evaluative Threat and Reward Processing

PubMed Central

Silk, Jennifer S.; Davis, Stephanie; McMakin, Dana L.; Dahl, Ronald E.; Forbes, Erika E.

2012-01-01

Background Depression is a leading cause of worldwide disability. Adolescence represents a key developmental window in which rates of this disorder increase markedly. Children with an anxiety disorder show a particular risk of developing depression during adolescence. Method We present and review evidence for a developmental model that considers the intersection of two vulnerabilities relevant to the trajectory from anxiety to depression: difficulties in response to potential social evaluation and changes in reward processing at puberty. Results Evidence suggests that these vulnerabilities (a) have been associated with depression, (b) are likely to be problematic in many but not all anxious youth, and (c) may be exacerbated by maturational processes that occur around pubertal development in ways that can create a negative spiral into a depressive disorder. Conclusions We discuss the possibility that early intervention strategies targeting key aspects of these vulnerabilities could alter the trajectory away from depression for many anxious youth. PMID:22340187

Perceptual Learning of Intonation Contour Categories in Adults and 9- to 11-Year-Old Children: Adults Are More Narrow-Minded.

PubMed

Kapatsinski, Vsevolod; Olejarczuk, Paul; Redford, Melissa A

2017-03-01

We report on rapid perceptual learning of intonation contour categories in adults and 9- to 11-year-old children. Intonation contours are temporally extended patterns, whose perception requires temporal integration and therefore poses significant working memory challenges. Both children and adults form relatively abstract representations of intonation contours: Previously encountered and novel exemplars are categorized together equally often, as long as distance from the prototype is controlled. However, age-related differences in categorization performance also exist. Given the same experience, adults form narrower categories than children. In addition, adults pay more attention to the end of the contour, while children appear to pay equal attention to the beginning and the end. The age range we examine appears to capture the tail-end of the developmental trajectory for learning intonation contour categories: There is a continuous effect of age on category breadth within the child group, but the oldest children (older than 10;3) are adult-like. Copyright © 2016 Cognitive Science Society, Inc.

Perceptual learning of intonation contour categories in adults and 9 to 11-year-old children: Adults are more narrow-minded

PubMed Central

Kapatsinski, Vsevolod; Olejarczuk, Paul; Redford, Melissa A.

2015-01-01

We report on rapid perceptual learning of intonation contour categories in adults and 9- to 11-year-old children. Intonation contours are temporally extended patterns whose perception requires temporal integration and therefore poses significant working memory challenges. Both children and adults form relatively abstract representations of intonation contours: previously encountered and novel exemplars are categorized together equally often, as long as distance from the prototype is controlled. However, age-related differences in categorization performance also exist. Given the same experience, adults form narrower categories than children. In addition, adults pay more attention to the end of the contour while children appear to pay equal attention to the beginning and the end. The age range we examine appears to capture the tail-end of the developmental trajectory for learning intonation contour categories: there is a continuous effect of age on category breadth within the child group, but the oldest children (older than 10;3) are adult-like. PMID:26901251

Maturation of the P3 and concurrent oscillatory processes during adolescence.

PubMed

Mathes, Birgit; Khalaidovski, Ksenia; Wienke, Annika S; Schmiedt-Fehr, Christina; Basar-Eroglu, Canan

2016-07-01

During adolescence event-related modulations of the neural response may increase. For slow event-related components, such as the P3, this developmental change may be masked due to increased amplitude levels of ongoing delta and theta oscillations in adolescents. In a cross-sectional study design, EEG was measured in 51 participants between 13 and 24years. A visual oddball paradigm was used to elicit the P3. Our analysis focused on fronto-parietal activations within the P3 time-window and the concurrent time-frequency characteristics in the delta (∼0.5-4Hz) and theta (∼4-7Hz) band. The parietal P3 amplitude was similar across the investigated age range, while the amplitude at frontal regions increased with age. The pre-stimulus amplitudes of delta and theta oscillations declined with age, while post-stimulus amplitude enhancement and inter-trial phase coherence increased. These changes affected fronto-parietal electrode sites. The parietal P3 maximum seemed comparable for adolescents and young adults. Detailed analysis revealed that within the P3 time-window brain maturation during adolescence may lead to reduced spontaneous slow-wave oscillations, increased amplitude modulation and time precision of event-related oscillations, and altered P3 scalp topography. Time-frequency analyses may help to distinguish selective neurodevelopmental changes within the P3 time window. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Ube3a reinstatement identifies distinct developmental windows in a murine Angelman syndrome model

PubMed Central

Silva-Santos, Sara; van Woerden, Geeske M.; Bruinsma, Caroline F.; Mientjes, Edwin; Jolfaei, Mehrnoush Aghadavoud; Distel, Ben; Kushner, Steven A.; Elgersma, Ype

2015-01-01

Angelman syndrome (AS) is a severe neurodevelopmental disorder that results from loss of function of the maternal ubiquitin protein ligase E3A (UBE3A) allele. Due to neuron-specific imprinting, the paternal UBE3A copy is silenced. Previous studies in murine models have demonstrated that strategies to activate the paternal Ube3a allele are feasible; however, a recent study showed that pharmacological Ube3a gene reactivation in adulthood failed to rescue the majority of neurocognitive phenotypes in a murine AS model. Here, we performed a systematic study to investigate the possibility that neurocognitive rescue can be achieved by reinstating Ube3a during earlier neurodevelopmental windows. We developed an AS model that allows for temporally controlled Cre-dependent induction of the maternal Ube3a allele and determined that there are distinct neurodevelopmental windows during which Ube3a restoration can rescue AS-relevant phenotypes. Motor deficits were rescued by Ube3a reinstatement in adolescent mice, whereas anxiety, repetitive behavior, and epilepsy were only rescued when Ube3a was reinstated during early development. In contrast, hippocampal synaptic plasticity could be restored at any age. Together, these findings suggest that Ube3a reinstatement early in development may be necessary to prevent or rescue most AS-associated phenotypes and should be considered in future clinical trial design. PMID:25866966

Windows of susceptibility and consequences of early life exposures to 17β–estradiol on medaka (Oryzias latipes) reproductive success

USGS Publications Warehouse

Lee Pow, Crystal S. D.; Tilahun, Kedamawit; Creech, Kari; Law, J. Mac; Cope, W. Gregory; Kwak, Thomas J.; Rice, James A.; Aday, D. Derek; Kullman, Seth W.

2017-01-01

Estrogens and estrogen mimics are commonly found in surface waters and are associated with deleterious effects in fish populations. Impaired fertility and fecundity in fish following chronic exposures to estrogens and estrogen mimics during critical windows in development are well documented. However, information regarding differential reproductive effects of exposure within defined developmental stages remains sparse. In this study, reproductive capacity was assessed in Japanese medaka (Oryzias latipes) after exposure to two concentrations of 17β–estradiol (E2β; 2 ng/L and 50 ng/L) during four distinct stages of development: gonad development, gonad differentiation, development of secondary sex characteristics (SSC) and gametogenesis. Exposure to E2β did not adversely impact survival, hatch success, growth, or genotypic ratios. In contrast, exposure to 50 ng/L E2β during SSC development altered phenotypic ratios and SSC. Exposure to both E2β treatments reduced reproductive capacity (fertility, fecundity) by 7.3–57.4% in adult medaka breeding pairs, with hindrance of SSC development resulting in the largest disruption in breeding capacity (51.6–57.4% decrease) in the high concentration. This study documents differential effects among four critical stages of development and provides insight into factors (window of exposure, exposure concentration and duration of exposure period) contributing to reproductive disruption in fish.

Resource quality affects weapon and testis size and the ability of these traits to respond to selection in the leaf-footed cactus bug, Narnia femorata.

PubMed

Sasson, Daniel A; Munoz, Patricio R; Gezan, Salvador A; Miller, Christine W

2016-04-01

The size of weapons and testes can be central to male reproductive success. Yet, the expression of these traits is often extremely variable. Studies are needed that take a more complete organism perspective, investigating the sources of variation in both traits simultaneously and using developmental conditions that mimic those in nature. In this study, we investigated the components of variation in weapon and testis sizes using the leaf-footed cactus bug, Narnia femorata (Hemiptera: Coreidae) on three natural developmental diets. We show that the developmental diet has profound effects on both weapon and testis expression and scaling. Intriguingly, males in the medium-quality diet express large weapons but have relatively tiny testes, suggesting complex allocation decisions. We also find that heritability, evolvability, and additive genetic variation are highest in the high-quality diet for testis and body mass. This result suggests that these traits may have an enhanced ability to respond to selection during a small window of time each year when this diet is available. Taken together, these results illustrate that normal, seasonal fluctuations in the nutritional environment may play a large role in the expression of sexually selected traits and the ability of these traits to respond to selection.

Evaluation of the developmental toxicity of lead in the Danio rerio body.

PubMed

Roy, Nicole M; DeWolf, Sarah; Carneiro, Bruno

2015-01-01

Lead has been utilized throughout history and is widely distributed and mobilized globally. Although lead in the environment has been somewhat mitigated, the nature of lead and its extensive uses in the past prohibit it from being completely absent from our environment and exposure to lead is still a public health concern. Most studies regarding lead toxicity have focused on the brain. However, little is found in the literature on the effects of lead in other tissues. Here, we utilize the zebrafish model system to investigate effects of lead exposure during early developmental time windows at 24, 48 and 72 h post fertilization in the body. We analyze whole body, notochord and somatic muscle changes, vascular changes of the body, as well as motor neuron alterations. We find lead exposure induces a curved body phenotype with concomitant changes in somite length, decreased notochord staining and abnormal muscle staining using live and in situ approaches. Furthermore, altered vasculature within the somatic regions, loss and/or alternations of motor neuron extension both dorsally and ventrally from the spinal cord, loss of Rohon-Beard sensory neurons, and increased areas of apoptosis were found. We conclude that lead is developmentally toxic to other areas of the developing embryo, not just the brain. Copyright © 2014 Elsevier B.V. All rights reserved.

When can parents most influence their child's development? Expert knowledge and perceived local realities.

PubMed

Worthman, Carol M; Tomlinson, Mark; Rotheram-Borus, Mary Jane

2016-04-01

Compelling evidence for the long-term impact of conditions in gestation and early childhood on both physical and psychosocial functioning and productivity has stimulated a focus in global health policy and social services on the "first 1000 days". Consequently, related initiatives may assume that rationale for this orientation and the agency of parents during this period is self-evident and widely shared among parents and communities. In 2012, we tested this assumption among a sample of 38 township-dwelling caregivers in Cape Town, by asking a question identified during a study of cultural models of parenting, namely: At what age or stage can a parent or caregiver have the most influence on a child's development? Formal cultural consensus analysis of responses met criteria for strong agreement that the period for greatest impact of parenting on a child's development occurs at adolescence, at a median age of 12 years. In follow-up focus groups and structured interviews, caregivers articulated clear ecological and developmental reasons for this view, related to protection both of developmental potential and against powerful, context-specific ecological risks (early pregnancy, substance ab/use, violence and gangs) that emerge during adolescence. Such risks threaten educational attainment, reproductive health, and social derailment with enduring consequences for lifetime well-being that caregivers are highly motivated to prevent. Developmental needs in pregnancy and early childhood, by contrast, were considered more manageable. These findings resonate with emerging evidence for multiple sensitive periods with corresponding developmental needs, and urge the value of complementing efforts to optimize early development with those to sustain and enhance it during later windows of developmental opportunity such as adolescence. Our results also indicate the need to consult local views of developmental risk and parenting practice in communicating with caregivers and planning interventions, and the value of using available methodological tools to do so. Copyright © 2016 Elsevier Ltd. All rights reserved.

When can parents most influence their child’s development? Expert knowledge and perceived local realities

PubMed Central

Worthman, Carol M.; Tomlinson, Mark; Rotheram-Borus, Mary Jane

2016-01-01

Compelling evidence for the long-term impact of conditions in gestation and early childhood on both physical and psychosocial functioning and productivity has stimulated a focus in global health policy and social services on the “first 1000 days”. Consequently, related initiatives may assume that rationale for this orientation and the agency of parents during this period is self-evident and widely shared among parents and communities. We tested this assumption in 2012 among a sample of 38 township-dwelling caregivers in Cape Town, by asking a question identified during a study of cultural models of parenting, namely: At what age or stage can a parent or caregiver have the most influence on a child’s development? Formal cultural consensus analysis of responses met criteria for strong agreement that the period for greatest impact of parenting on a child’s development occurs at adolescence, at a median age of 12 years. In follow-up focus groups and structured interviews, caregivers articulated clear ecological and developmental reasons for this view, related to protection both of developmental potential and against powerful, context-specific ecological risks (early pregnancy, substance ab/use, violence and gangs) that emerge during adolescence. Such risks threaten educational attainment, reproductive health, and social derailment with enduring consequences for lifetime well-being that caregivers are highly motivated to prevent. Developmental needs in pregnancy and early childhood, by contrast, were considered more manageable. These findings resonate with emerging evidence for multiple sensitive periods with corresponding developmental needs, and urge the value of complementing efforts to optimize early development with those to sustain and enhance it during later windows of developmental opportunity such as adolescence. Our results also indicate the need to consult local views of developmental risk and parenting practice in communicating with caregivers and planning interventions, and the value of using available methodological tools to do so. PMID:26945544

Determination of electron energy, spectral width, and beam divergence at the exit window for clinical megavoltage x-ray beams.

PubMed

Sawkey, D L; Faddegon, B A

2009-03-01

Monte Carlo simulations of x-ray beams typically take parameters of the electron beam in the accelerating waveguide to be free parameters. In this paper, a methodology is proposed and implemented to determine the energy, spectral width, and beam divergence of the electron source. All treatment head components were removed from the beam path, leaving only the exit window. With the x-ray target and flattener out of the beam, uncertainties in physical characteristics and relative position of the target and flattening filter, and in spot size, did not contribute to uncertainty in the energy. Beam current was lowered to reduce recombination effects. The measured dose distributions were compared with Monte Carlo simulation of the electron beam through the treatment head to extract the electron source characteristics. For the nominal 6 and 18 MV x-ray beams, the energies were 6.51 +/- 0.15 and 13.9 +/- 0.2 MeV, respectively, with the uncertainties resulting from uncertainties in the detector position in the measurement and in the stopping power in the simulations. Gaussian spectral distributions were used, with full widths at half maximum ranging from 20 +/- 4% at 6 MV to 13 +/- 4% at 18 MV required to match the fall-off portion of the percent-depth ionization curve. Profiles at the depth of maximum dose from simulations that used the manufacturer-specified exit window geometry and no beam divergence were 2-3 cm narrower than measured profiles. Two simulation configurations yielding the measured profile width were the manufacturer-specified exit window thickness with electron source divergences of 3.3 degrees at 6 MV and 1.8 degrees at 18 MV and an exit window 40% thicker than the manufacturer's specification with no beam divergence. With the x-ray target in place (and no flattener), comparison of measured to simulated profiles sets upper limits on the electron source divergences of 0.2 degrees at 6 MV and 0.1 degrees at 18 MV. A method of determining source characteristics without mechanical modification of the treatment head, and therefore feasible in clinics, is presented. The energies and spectral widths determined using this method agree with those determined with only the exit window in the beam path.

Size and Location of Defects at the Coupling Interface Affect Lithotripter Performance

PubMed Central

Li, Guangyan; Williams, James C.; Pishchalnikov, Yuri A.; Liu, Ziyue; McAteer, James A.

2012-01-01

OBJECTIVE To determine how the size and location of coupling defects caught between the therapy head of a lithotripter and the skin of a surrogate patient (acoustic window of a test chamber) affect the features of shock waves responsible for stone breakage. METHODS Model defects were placed in the coupling gel between the therapy head of a Dornier Compact-S electromagnetic lithotripter and the Mylar window of a water-filled coupling test system. A fiber-optic hydrophone was used to measure acoustic pressures and map the lateral dimensions of the focal zone of the lithotripter. The effect of coupling conditions on stone breakage was assessed using Gypsum model stones. RESULTS Stone breakage decreased in proportion to the area of the coupling defect; a centrally located defect blocking only 18% of the transmission area reduced stone breakage by an average of almost 30%. The effect on stone breakage was greater for defects located on-axis and decreased as the defect was moved laterally; an 18% defect located near the periphery of the coupling window (2.0 cm off-axis) reduced stone breakage by only ~15% compared to when coupling was completely unobstructed. Defects centered within the coupling window acted to narrow the focal width of the lithotripter; an 8.2% defect reduced the focal width ~30% compared to no obstruction (4.4 mm versus 6.5 mm). Coupling defects located slightly off center disrupted the symmetry of the acoustic field; an 18% defect positioned 1.0 cm off-axis shifted the focus of maximum positive pressure ~1.0 mm laterally. Defects on and off-axis imposed a significant reduction in the energy density of shock waves across the focal zone. CONCLUSIONS In addition to blocking the transmission of shock wave energy, coupling defects also disrupt the properties of shock waves that play a role in stone breakage, including the focal width of the lithotripter and the symmetry of the acoustic field; the effect is dependent on the size and location of defects, with defects near the center of the coupling window having the greatest effect. These data emphasize the importance of eliminating air pockets from the coupling interface, particularly defects located near the center of the coupling window. PMID:22938566

Use of DES Modeling for Determining Launch Availability for SLS

NASA Technical Reports Server (NTRS)

Watson, Michael; Staton, Eric; Cates, Grant; Finn, Ronald; Altino, Karen M.; Burns, K. Lee

2014-01-01

(1) NASA is developing a new heavy lift launch system for human and scientific exploration beyond Earth orbit comprising of the Space Launch System (SLS), Orion Multi-Purpose Crew Vehicle (MPCV), and Ground Systems Development and Operations (GSDO); (2) The desire of the system is to ensure a high confidence of successfully launching the exploration missions, especially those that require multiple launches, have a narrow Earth departure window, and high investment costs; and (3) This presentation discusses the process used by a Cross-Program team to develop the Exploration Systems Development (ESD) Launch Availability (LA) Technical Performance Measure (TPM) and allocate it to each of the Programs through the use of Discrete Event Simulations (DES).

Image segmentation of pyramid style identifier based on Support Vector Machine for colorectal endoscopic images.

PubMed

Okamoto, Takumi; Koide, Tetsushi; Sugi, Koki; Shimizu, Tatsuya; Anh-Tuan Hoang; Tamaki, Toru; Raytchev, Bisser; Kaneda, Kazufumi; Kominami, Yoko; Yoshida, Shigeto; Mieno, Hiroshi; Tanaka, Shinji

2015-08-01

With the increase of colorectal cancer patients in recent years, the needs of quantitative evaluation of colorectal cancer are increased, and the computer-aided diagnosis (CAD) system which supports doctor's diagnosis is essential. In this paper, a hardware design of type identification module in CAD system for colorectal endoscopic images with narrow band imaging (NBI) magnification is proposed for real-time processing of full high definition image (1920 × 1080 pixel). A pyramid style image segmentation with SVMs for multi-size scan windows, which can be implemented on an FPGA with small circuit area and achieve high accuracy, is proposed for actual complex colorectal endoscopic images.

Orbital selective directional conductor in the two-orbital Hubbard model

DOE PAGES

Mukherjee, Anamitra; Patel, Niravkumar D.; Moreo, Adriana; ...

2016-02-29

Recently, we employed a developed many-body technique that allows for the incorporation of thermal effects, the rich phase diagram of a two-dimensional two-orbital (degenerate d xz and d yz) Hubbard model is presented varying temperature and the repulsion U. The main result is the finding at intermediate U of an antiferromagnetic orbital selective state where an effective dimensional reduction renders one direction insulating and the other metallic. Possible realizations of this state are discussed. Additionally, we also study nematicity above the N eel temperature. After a careful finite-size scaling analysis, the nematicity temperature window appears to survive in the bulkmore » limit, although it is very narrow.« less

Tunable electromagnetically induced absorption based on graphene

NASA Astrophysics Data System (ADS)

Cao, Maoyong; Wang, Tongling; Zhang, Huiyun; Zhang, Yuping

2018-04-01

In this paper, an electronically induced absorption (EIA) structure based on graphene at the infrared frequency is proposed. A pair of nanorods is coupled to a ring resonator, resulting in electronically induced transparency (EIT), and then, Babinet's principle is applied to transform the EIT structure into an EIA structure. Based on the bright and dark modes of the coupling schemes, the adjustment of the coupling strength between the dark and bright modes can be achieved by changing the asymmetry degree. In addition, the transparency window and the absorption peak can be tuned by changing the Fermi energy of graphene. This graphene-based EIA structure can develop the path in narrow-band filtering and, absorptive switching in the future.

Surface Temperature Dependence of Hydrogen Ortho-Para Conversion on Amorphous Solid Water.

PubMed

Ueta, Hirokazu; Watanabe, Naoki; Hama, Tetsuya; Kouchi, Akira

2016-06-24

The surface temperature dependence of the ortho-to-para conversion of H_{2} on amorphous solid water is first reported. A combination of photostimulated desorption and resonance-enhanced multiphoton ionization techniques allowed us to sensitively probe the conversion on the surface of amorphous solid water at temperatures of 9.2-16 K. Within a narrow temperature window of 8 K, the conversion time steeply varied from ∼4.1×10^{3} to ∼6.4×10^{2}  s. The observed temperature dependence is discussed in the context of previously suggested models and the energy dissipation process. The two-phonon process most likely dominates the conversion rate at low temperatures.

Vitamin K antagonists and direct thrombin inhibitors: present and future.

PubMed

Pineo, Graham F; Hull, Russell D

2005-02-01

Warfarin and related compounds are efficacious and safe in a variety of clinical thrombotic disorders; however, these drugs have a narrow therapeutic window, whereby inadequate therapy is associated with an increased thrombotic risk and overanticoagulation is associated with bleeding. Therefore, attempts have been made to develop alternatives to warfarin. Ximelagatran, an oral direct thrombin inhibitor, has been shown to be as efficacious and safe as warfarin for the prevention and treatment of different thrombotic disorders. This article reviews the pharmacology of the coumarins, the most commonly used vitamin K antagonists, and the practical aspects regarding their use in the management of thrombotic disorders. The future role of the oral direct thrombin inhibitor ximelagatran also is reviewed.

Current and future bioanalytical approaches for stroke assessment.

PubMed

Pullagurla, Swathi R; Baird, Alison E; Adamski, Mateusz G; Soper, Steven A

2015-01-01

Efforts are underway to develop novel platforms for stroke diagnosis to meet the criteria for effective treatment within the narrow time window mandated by the FDA-approved therapeutic (<3 h). Blood-based biomarkers could be used for rapid stroke diagnosis and coupled with new analytical tools, could serve as an attractive platform for managing stroke-related diseases. In this review, we will discuss the physiological processes associated with stroke and current diagnostic tools as well as their associated shortcomings. We will then review information on blood-based biomarkers and various detection technologies. In particular, point of care testing that permits small blood volumes required for the analysis and rapid turn-around time measurements of multiple markers will be presented.

Analyzing Transient Turbuelnce in a Stenosed Carotid Artery by Proper Orthogonal Decomposition

NASA Astrophysics Data System (ADS)

Grinberg, Leopold; Yakhot, Alexander; Karniadakis, George

2009-11-01

High resolution 3D simulation (involving 100M degrees of freedom) were employed to study transient turbulent flow in a carotid arterial bifurcation with a stenosed internal carotid artery (ICA). In the performed simulation an intermittent (in space and time) laminar-turbulent-laminar regime was observed. The simulation reveals the mechanism of the onset of turbulent flow in the stenosed ICA where the narrowing in the artery generates a strong jet flow. Time- and space-window Proper Orthogonal Decomposition (POD) was applied to quantify the different flow regimes in the occluded artery. A simplified version of the POD analysis that utilizes 2D slices only - more appropriate in the clinical setting - was also investigated.

Multisensory integration and ADHD-like traits: Evidence for an abnormal temporal integration window in ADHD.

PubMed

Panagiotidi, Maria; Overton, Paul G; Stafford, Tom

2017-11-01

Abnormalities in multimodal processing have been found in many developmental disorders such as autism and dyslexia. However, surprisingly little empirical work has been conducted to test the integrity of multisensory integration in Attention Deficit Hyperactivity Disorder (ADHD). The main aim of the present study was to examine links between symptoms of ADHD (as measured using a self-report scale in a healthy adult population) and the temporal aspects of multisensory processing. More specifically, a Simultaneity Judgement (SJ) and a Temporal Order Judgement (TOJ) task were used in participants with low and high levels of ADHD-like traits to measure the temporal integration window and Just-Noticeable Difference (JND) (respectively) between the timing of an auditory beep and a visual pattern presented over a broad range of stimulus onset asynchronies. The Point of Subjective Similarity (PSS) was also measured in both cases. In the SJ task, participants with high levels of ADHD-like traits considered significantly fewer stimuli to be simultaneous than participants with high levels of ADHD-like traits, and the former were found to have significantly smaller temporal windows of integration (although no difference was found in the PSS in the SJ or TOJ tasks, or the JND in the latter). This is the first study to identify an abnormal temporal integration window in individuals with ADHD-like traits. Perceived temporal misalignment of two or more modalities can lead to distractibility (e.g., when the stimulus components from different modalities occur separated by too large of a temporal gap). Hence, an abnormality in the perception of simultaneity could lead to the increased distractibility seen in ADHD. Copyright © 2017 Elsevier B.V. All rights reserved.

Titan's Surface Composition from Cassini VIMS Solar Occultation Observations

NASA Astrophysics Data System (ADS)

McCord, Thomas; Hayne, Paul; Sotin, Christophe

2013-04-01

Titan's surface is obscured by a thick absorbing and scattering atmosphere, allowing direct observation of the surface within only a few spectral win-dows in the near-infrared, complicating efforts to identify and map geologi-cally important materials using remote sensing IR spectroscopy. We there-fore investigate the atmosphere's infrared transmission with direct measure-ments using Titan's occultation of the Sun as well as Titan's reflectance measured at differing illumination and observation angles observed by Cas-sini's Visual and Infrared Mapping Spectrometer (VIMS). We use two im-portant spectral windows: the 2.7-2.8-mm "double window" and the broad 5-mm window. By estimating atmospheric attenuation within these windows, we seek an empirical correction factor that can be applied to VIMS meas-urements to estimate the true surface reflectance and map inferred composi-tional variations. Applying the empirical corrections, we correct the VIMS data for the viewing geometry-dependent atmospheric effects to derive the 5-µm reflectance and 2.8/2.7-µm reflectance ratio. We then compare the cor-rected reflectances to compounds proposed to exist on Titan's surface. We propose a simple correction to VIMS Titan data to account for atmospheric attenuation and diffuse scattering in the 5-mm and 2.7-2.8 mm windows, generally applicable for airmass < 3.0. We propose a simple correction to VIMS Titan data to account for atmospheric attenuation and diffuse scatter-ing in the 5-mm and 2.7-2.8 mm windows, generally applicable for airmass < 3.0. The narrow 2.75-mm absorption feature, dividing the window into two sub-windows, present in all on-planet measurements is not present in the occultation data, and its strength is reduced at the cloud tops, suggesting the responsible molecule is concentrated in the lower troposphere or on the sur-face. Our empirical correction to Titan's surface reflectance yields properties shifted closer to water ice for the majority of the low-to-mid latitude area covered by VIMS measurements. Four compositional units are defined and mapped on Titan's surface based on the positions of data clusters in 5-mm vs. 2.8/2.7-mm scatter plots; a simple ternary mixture of H2O, hydrocarbons and CO2 might explain the reflectance properties of these surface units. The vast equatorial "dune seas" are compositionally very homogeneous, perhaps suggesting transport and mixing of particles over very large distances and/or and very consistent formation process and source material. The composi-tional branch characterizing Tui Regio and Hotei Regio is consistent with a mixture of typical Titan hydrocarbons and CO2, or possibly methane/ethane; the concentration mechanism proposed is something similar to a terrestrial playa lake evaporate deposit, based on the fact that river channels are known to feed into at least Hotei Regio.

Effect of temperature and nutrients on the growth and development of seedlings of an invasive plant.

PubMed

Skálová, Hana; Moravcová, Lenka; Dixon, Anthony F G; Kindlmann, P; Pyšek, Petr

2015-04-28

Plant species distributions are determined by the response of populations to regional climates; however, little is known about how alien plants that arrive in central Europe from climatically warmer regions cope with the temperature conditions at the early stage of population development. Ambrosia artemisiifolia (common ragweed) is an invasive annual plant causing considerable health and economic problems in Europe. Although climate-based models predict that the whole of the Czech Republic is climatically suitable for this species, it is confined to the warmest regions. To determine the factors possibly responsible for its restricted occurrence, we investigated the effects of temperature and nutrient availability on its seedlings. The plants were cultivated at one of seven temperature regimes ranging from 10 to 34 °C, combined with three nutrient levels. The data on the rate of leaf development were used to calculate the lower developmental threshold (LDT, the temperature, in °C, below which development ceases), the sum of effective temperatures (SET, the amount of heat needed to complete a developmental stage measured in degree days above LDT) and width of the thermal window. The rate of development decreased with decrease in temperature and nutrient supply. Besides this, the decrease in the availability of nutrients resulted in decreased LDT, increased SET and wider thermal window. The dependence of LDT and SET on the availability of nutrients contradicts the concept that thermal constants do not vary. Our results highlight temperature as the main determinant of common ragweed's distribution and identify nutrient availability as a factor that results in the realized niche being smaller than the fundamental niche; both of these need to be taken into account when predicting the future spread of A. artemisiifolia. Published by Oxford University Press on behalf of the Annals of Botany Company.

Motoneuron axon pathfinding errors in zebrafish: Differential effects related to concentration and timing of nicotine exposure

PubMed Central

Menelaou, Evdokia; Paul, Latoya T.; Perera, Surangi N.; Svoboda, Kurt R.

2015-01-01

Nicotine exposure during embryonic stages of development can affect many neurodevelopmental processes. In the developing zebrafish, exposure to nicotine was reported to cause axonal pathfinding errors in the later born secondary motoneurons (SMN). These alterations in SMN axon morphology coincided with muscle degeneration at high nicotine concentrations (15–30µM). Previous work showed that the paralytic mutant zebrafish known as sofa potato, exhibited nicotine-induced effects onto SMN axons at these high concentrations but in the absence of any muscle deficits, indicating that pathfinding errors could occur independent of muscle effects. In this study, we used varying concentrations of nicotine at different developmental windows of exposure to specifically isolate its effects onto subpopulations of motoneuron axons. We found that nicotine exposure can affect SMN axon morphology in a dose-dependent manner. At low concentrations of nicotine, SMN axons exhibited pathfinding errors, in the absence of any nicotine-induced muscle abnormalities. Moreover, the nicotine exposure paradigms used affected the 3 subpopulations of SMN axons differently, but the dorsal projecting SMN axons were primarily affected. We then identified morphologically distinct pathfinding errors that best described the nicotine-induced effects on dorsal projecting SMN axons. To test whether SMN pathfinding was potentially influenced by alterations in the early born primary motoneuron (PMN), we performed dual labeling studies, where both PMN and SMN axons were simultaneously labeled with antibodies. We show that only a subset of the SMN axon pathfinding errors coincided with abnormal PMN axonal targeting in nicotine-exposed zebrafish. We conclude that nicotine exposure can exert differential effects depending on the levels of nicotine and developmental exposure window. PMID:25668718

Exposure to butachlor causes thyroid endocrine disruption and promotion of metamorphosis in Xenopus laevis.

PubMed

Li, Shuying; Li, Meng; Wang, Qiangwei; Gui, Wenjun; Zhu, Guonian

2016-06-01

Butachlor is extensively applied in rice paddy ecosystem in china, and has been widespread contaminant in the aquatic environment. Here, Xenopus laevis was used for the evaluation of teratogenesis developmental toxicity, and disruption of thyroid system when exposure to different concentrations of butachlor by window phase exposure. Acute toxicity investigation shown that 96 h-LC50 value of butachlor was 1.424 mg L(-1) and 0.962 mg L(-1) for tadpoles (starting from stages 46/47) and embryos (starting from stages 8/9), respectively. Exposure to butachlor caused malformation, including abnormal eye, pericardial edema, enlarged proctodaeum and bent tail. Window phase exposure test indicated that butachlor significantly promote the contents of whole-body thyroid hormones (THs, T3 and T4) at higher levels, indicating thyroid endocrine disruption. At 7 days, exposure to butachlor up-regulated the mRNA expression of genes involved in THs synthesis and metabolism (tshα, tg, tpo and dio1) and THs receptors (trα and trβ). At 14 days, up-regulation of the mRNA expression of genes related to THs synthesis and metabolism (tshα, tshβ, tg, tpo, dio1, dio2 and ttr) and THs receptors (trβ) were also observed after the exposure to butachlor. At 21 days, butachlor up-regulated the mRNA expression of tshα, tg, tpo genes and down-regulated the mRNA expression of tshβ, tg, dio1, ttr and trα genes. These results showed that butachlor could change the mRNA expression of genes involved in the HPT axis and increase whole-body thyroid hormones levels of X. laevis tadpoles in a dose- and time-dependent manner, causing thyroid endocrine disruption and developmental toxicity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lace plant ethylene receptors, AmERS1a and AmERS1c, regulate ethylene-induced programmed cell death during leaf morphogenesis.

PubMed

Rantong, Gaolathe; Evans, Rodger; Gunawardena, Arunika H L A N

2015-10-01

The lace plant, Aponogeton madagascariensis, is an aquatic monocot that forms perforations in its leaves as part of normal leaf development. Perforation formation occurs through developmentally regulated programmed cell death (PCD). The molecular basis of PCD regulation in the lace plant is unknown, however ethylene has been shown to play a significant role. In this study, we examined the role of ethylene receptors during perforation formation. We isolated three lace plant ethylene receptors AmERS1a, AmERS1b and AmERS1c. Using quantitative PCR, we examined their transcript levels at seven stages of leaf development. Through laser-capture microscopy, transcript levels were also determined in cells undergoing PCD and cells not undergoing PCD (NPCD cells). AmERS1a transcript levels were significantly lower in window stage leaves (in which perforation formation and PCD are occurring) as compared to all other leaf developmental stages. AmERS1a and AmERS1c (the most abundant among the three receptors) had the highest transcript levels in mature stage leaves, where PCD is not occurring. Their transcript levels decreased significantly during senescence-associated PCD. AmERS1c had significantly higher transcript levels in NPCD compared to PCD cells. Despite being significantly low in window stage leaves, AmERS1a transcripts were not differentially expressed between PCD and NPCD cells. The results suggested that ethylene receptors negatively regulate ethylene-controlled PCD in the lace plant. A combination of ethylene and receptor levels determines cell fate during perforation formation and leaf senescence. A new model for ethylene emission and receptor expression during lace plant perforation formation and senescence is proposed.

The persistent sampling bias in developmental psychology: A call to action.

PubMed

Nielsen, Mark; Haun, Daniel; Kärtner, Joscha; Legare, Cristine H

2017-10-01

Psychology must confront the bias in its broad literature toward the study of participants developing in environments unrepresentative of the vast majority of the world's population. Here, we focus on the implications of addressing this challenge, highlight the need to address overreliance on a narrow participant pool, and emphasize the value and necessity of conducting research with diverse populations. We show that high-impact-factor developmental journals are heavily skewed toward publishing articles with data from WEIRD (Western, educated, industrialized, rich, and democratic) populations. Most critically, despite calls for change and supposed widespread awareness of this problem, there is a habitual dependence on convenience sampling and little evidence that the discipline is making any meaningful movement toward drawing from diverse samples. Failure to confront the possibility that culturally specific findings are being misattributed as universal traits has broad implications for the construction of scientifically defensible theories and for the reliable public dissemination of study findings. Copyright © 2017 Elsevier Inc. All rights reserved.

Whole-organ cell shape analysis reveals the developmental basis of ascidian notochord taper.

PubMed

Veeman, Michael T; Smith, William C

2013-01-15

Here we use in toto imaging together with computational segmentation and analysis methods to quantify the shape of every cell at multiple stages in the development of a simple organ: the notochord of the ascidian Ciona savignyi. We find that cell shape in the intercalated notochord depends strongly on anterior-posterior (AP) position, with cells in the middle of the notochord consistently wider than cells at the anterior or posterior. This morphological feature of having a tapered notochord is present in many chordates. We find that ascidian notochord taper involves three main mechanisms: Planar Cell Polarity (PCP) pathway-independent sibling cell volume asymmetries that precede notochord cell intercalation; the developmental timing of intercalation, which proceeds from the anterior and posterior towards the middle; and the differential rates of notochord cell narrowing after intercalation. A quantitative model shows how the morphology of an entire developing organ can be controlled by this small set of cellular mechanisms. Copyright © 2012 Elsevier Inc. All rights reserved.

Whole-organ cell shape analysis reveals the developmental basis of ascidian notochord taper

PubMed Central

Veeman, Michael T.; Smith, William C.

2012-01-01

Here we use in toto imaging together with computational segmentation and analysis methods to quantify the shape of every cell at multiple stages in the development of a simple organ: the notochord of the ascidian Ciona savignyi. We find that cell shape in the intercalated notochord depends strongly on anterior-posterior (AP) position, with cells in the middle of the notochord consistently wider than cells at the anterior or posterior. This morphological feature of having a tapered notochord is present in many chordates. We find that ascidian notochord taper involves three main mechanisms: Planar Cell Polarity (PCP) pathway-independent sibling cell volume asymmetries that precede notochord cell intercalation; the developmental timing of intercalation, which proceeds from the anterior and posterior towards the middle; and the differential rates of notochord cell narrowing after intercalation. A quantitative model shows how the morphology of an entire developing organ can be controlled by this small set of cellular mechanisms. PMID:23165294

Perceptual learning shapes multisensory causal inference via two distinct mechanisms

PubMed Central

McGovern, David P.; Roudaia, Eugenie; Newell, Fiona N.; Roach, Neil W.

2016-01-01

To accurately represent the environment, our brains must integrate sensory signals from a common source while segregating those from independent sources. A reasonable strategy for performing this task is to restrict integration to cues that coincide in space and time. However, because multisensory signals are subject to differential transmission and processing delays, the brain must retain a degree of tolerance for temporal discrepancies. Recent research suggests that the width of this ‘temporal binding window’ can be reduced through perceptual learning, however, little is known about the mechanisms underlying these experience-dependent effects. Here, in separate experiments, we measure the temporal and spatial binding windows of human participants before and after training on an audiovisual temporal discrimination task. We show that training leads to two distinct effects on multisensory integration in the form of (i) a specific narrowing of the temporal binding window that does not transfer to spatial binding and (ii) a general reduction in the magnitude of crossmodal interactions across all spatiotemporal disparities. These effects arise naturally from a Bayesian model of causal inference in which learning improves the precision of audiovisual timing estimation, whilst concomitantly decreasing the prior expectation that stimuli emanate from a common source. PMID:27091411

Face perception is tuned to horizontal orientation in the N170 time window.

PubMed

Jacques, Corentin; Schiltz, Christine; Goffaux, Valerie

2014-02-07

The specificity of face perception is thought to reside both in its dramatic vulnerability to picture-plane inversion and its strong reliance on horizontally oriented image content. Here we asked when in the visual processing stream face-specific perception is tuned to horizontal information. We measured the behavioral performance and scalp event-related potentials (ERP) when participants viewed upright and inverted images of faces and cars (and natural scenes) that were phase-randomized in a narrow orientation band centered either on vertical or horizontal orientation. For faces, the magnitude of the inversion effect (IE) on behavioral discrimination performance was significantly reduced for horizontally randomized compared to vertically or nonrandomized images, confirming the importance of horizontal information for the recruitment of face-specific processing. Inversion affected the processing of nonrandomized and vertically randomized faces early, in the N170 time window. In contrast, the magnitude of the N170 IE was much smaller for horizontally randomized faces. The present research indicates that the early face-specific neural representations are preferentially tuned to horizontal information and offers new perspectives for a description of the visual information feeding face-specific perception.

Head posture measurements among work vehicle drivers and implications for work and workplace design.

PubMed

Eklund, J; Odenrick, P; Zettergren, S; Johansson, H

1994-04-01

An increased risk of musculoskeletal disorders, e.g. from the neck region, has been found among professional drivers of work vehicles. The purpose of this study was to identify causes of postural load and implications for vehicle design and work tasks. A second purpose was to develop the methods for measurement and analysis of head postures. Field measurements of head postures for drivers of fork lift trucks, forestry machines, and cranes were carried out. The equipment used was an electric goniometer measurement system, containing a mechanical transmission between the head and the upper trunk. Methods for data presentation and quantification were developed. The results showed that rotatable and movable driver cabins improved head postures and viewing angles substantially. Narrow window frame structures and large, optimally-placed windows were also advantageous. The steering wheel, controls, and a high backrest restricted shoulder rotation, which increased head rotation in unfavourable viewing angles. Improved workspace layouts and work organization factors such as job enlargement decreased the influence of strenuous postures. The results also showed that head postures should be analysed in two or three dimensions simultaneously, otherwise the postures taken will be underestimated in relation to the maximal voluntary movement.

Baclofen novel gastroretentive extended release gellan gum superporous hydrogel hybrid system: in vitro and in vivo evaluation.

PubMed

El-Said, Ibrahim A; Aboelwafa, Ahmed A; Khalil, Rawia M; ElGazayerly, Omaima N

2016-01-01

Baclofen is a centrally acting skeletal muscle relaxant with a short elimination half-life, which results in frequent daily dosing and subsequent poor patient compliance. The narrow absorption window of baclofen in the upper gastrointestinal tract limits its formulation as extended release dosage forms. In this study, baclofen extended release superporous hydrogel (SPH) systems, including conventional SPH, SPH composite and SPH hybrid (SPHH), were prepared aiming to increase the residence of baclofen at its absorption window. The applicability of different polymers, namely, gellan gum, guar gum, polyvinyl alcohol and gelatin, was investigated in preparation of SPHH systems. The prepared SPH systems were evaluated regarding weight and volume swelling ratio, porosity, mechanical properties, incorporation efficiency, degree of erosion and drug release. In vivo assessment was performed in dogs to evaluate gastric residence time by X-ray studies. In addition, the oral bioavailability of baclofen relative to commercially available Lioresal® immediate release tablets was also investigated. The novel baclofen gellan SPHH cross linked with calcium chloride was characterized by optimum mechanical properties, acceptable swelling properties as well as extended drug release. It also exhibited a prolonged plasma profile when compared to twice daily administered Lioresal®.

Large reversible magnetocaloric effect in a Ni-Co-Mn-In magnetic shape memory alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, L.; Cong, D. Y.; Ma, L.

Reversibility of the magnetocaloric effect in materials with first-order magnetostructural transformation is of vital significance for practical magnetic refrigeration applications. Here, we report a large reversible magnetocaloric effect in a Ni49.8Co1.2Mn33.5In15.5 magnetic shape memory alloy. A large reversible magnetic entropy change of 14.6 J/(kg K) and a broad operating temperature window of 18 K under 5 T were simultaneously achieved, correlated with the low thermal hysteresis (-8 K) and large magnetic-field-induced shift of transformation temperatures (4.9 K/T) that lead to a narrow magnetic hysteresis (1.1 T) and small average magnetic hysteresis loss (48.4 J/kg under 5 T) as well. Furthermore,more » a large reversible effective refrigeration capacity (76.6 J/kg under 5 T) was obtained, as a result of the large reversible magnetic entropy change, broad operating temperature window, and small magnetic hysteresis loss. The large reversible magnetic entropy change and large reversible effective refrigeration capacity are important for improving the magnetocaloric performance, and the small magnetic hysteresis loss is beneficial to reducing energy dissipation during magnetic field cycle in potential applications.« less

Sitting in the Pilot's Seat; Optimizing Human-Systems Interfaces for Unmanned Aerial Vehicles

NASA Technical Reports Server (NTRS)

Queen, Steven M.; Sanner, Kurt Gregory

2011-01-01

One of the pilot-machine interfaces (the forward viewing camera display) for an Unmanned Aerial Vehicle called the DROID (Dryden Remotely Operated Integrated Drone) will be analyzed for optimization. The goal is to create a visual display for the pilot that as closely resembles an out-the-window view as possible. There are currently no standard guidelines for designing pilot-machine interfaces for UAVs. Typically, UAV camera views have a narrow field, which limits the situational awareness (SA) of the pilot. Also, at this time, pilot-UAV interfaces often use displays that have a diagonal length of around 20". Using a small display may result in a distorted and disproportional view for UAV pilots. Making use of a larger display and a camera lens with a wider field of view may minimize the occurrences of pilot error associated with the inability to see "out the window" as in a manned airplane. It is predicted that the pilot will have a less distorted view of the DROID s surroundings, quicker response times and more stable vehicle control. If the experimental results validate this concept, other UAV pilot-machine interfaces will be improved with this design methodology.

Voluntary and Involuntary Movements Widen the Window of Subjective Simultaneity.

PubMed

Arikan, B Ezgi; van Kemenade, Bianca M; Straube, Benjamin; Harris, Laurence R; Kircher, Tilo

2017-01-01

Forming a coherent percept of an event requires different sensory inputs originating from the event to be bound. Perceiving synchrony aids in binding of these inputs. In two experiments, we investigated how voluntary movements influence the perception of simultaneity, by measuring simultaneity judgments (SJs) for an audiovisual (AV) stimulus pair triggered by a voluntary button press. In Experiment 1, we manipulated contiguity between the action and its consequences by introducing delays between the button press and the AV stimulus pair. We found a widened window of subjective simultaneity (WSS) when the action-feedback relationship was time contiguous. Introducing a delay narrowed the WSS, suggesting that the wider WSS around the time of an action might facilitate perception of simultaneity. In Experiment 2, we introduced an involuntary condition using an externally controlled button to assess the influence of action-related predictive processes on SJs. We found a widened WSS around the action time, regardless of movement type, supporting the influence of causal relations in the perception of synchrony. Interestingly, the slopes of the psychometric functions in the voluntary condition were significantly steeper than the slopes in the involuntary condition, suggesting a role of action-related predictive mechanisms in making SJs more precise.

Voluntary and Involuntary Movements Widen the Window of Subjective Simultaneity

PubMed Central

Arikan, B. Ezgi; van Kemenade, Bianca M.; Straube, Benjamin; Harris, Laurence R.; Kircher, Tilo

2017-01-01

Forming a coherent percept of an event requires different sensory inputs originating from the event to be bound. Perceiving synchrony aids in binding of these inputs. In two experiments, we investigated how voluntary movements influence the perception of simultaneity, by measuring simultaneity judgments (SJs) for an audiovisual (AV) stimulus pair triggered by a voluntary button press. In Experiment 1, we manipulated contiguity between the action and its consequences by introducing delays between the button press and the AV stimulus pair. We found a widened window of subjective simultaneity (WSS) when the action-feedback relationship was time contiguous. Introducing a delay narrowed the WSS, suggesting that the wider WSS around the time of an action might facilitate perception of simultaneity. In Experiment 2, we introduced an involuntary condition using an externally controlled button to assess the influence of action-related predictive processes on SJs. We found a widened WSS around the action time, regardless of movement type, supporting the influence of causal relations in the perception of synchrony. Interestingly, the slopes of the psychometric functions in the voluntary condition were significantly steeper than the slopes in the involuntary condition, suggesting a role of action-related predictive mechanisms in making SJs more precise. PMID:28835813

Reproduction, embryonic development, and maternal transfer of contaminants in the amphibian Gastrophryne carolinensis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopkins, W.A.; DuRant, S.E.; Staub, B.P.

2006-05-15

Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. We examined maternal transfer of contaminants in eastern narrow-mouth toads (Gastrophryne carolinensis) collected from a reference site and near a coal-burning power plant. Adult toads inhabiting the industrial area transferred significant quantities of selenium and strontium to their eggs, but Se concentrations were most notable (up to 100 {mu} g/g dry mass). Compared with the reference site, hatching success was reducedmore » by 11% in clutches from the contaminated site. In surviving larvae, the frequency of developmental abnormalities and abnormal swimming was 55-58% higher in the contaminated site relative to the reference site. Craniofacial abnormalities were nearly an order of magnitude more prevalent in hatchlings from the contaminated site. When all developmental criteria were considered collectively, offspring from the contaminated site experienced 19% lower viability. Although there was no statistical relationship between the concentration of Se or Sr transferred to eggs and any measure of offspring viability, our study demonstrates that maternal transfer may be an important route of contaminant exposure in amphibians that has been overlooked.« less

Jaw-phonatory coordination in chronic developmental stuttering.

PubMed

Loucks, Torrey M J; De Nil, Luc F; Sasisekaran, Jayanthi

2007-01-01

A deficiency in sensorimotor integration in a person who stutters may be a factor in the pathophysiology of developmental stuttering. To test oral sensorimotor function in adults who stutter, we used a task that requires the coordination of a jaw-opening movement with phonation onset. The task was adapted from previous limb coordination studies, which show that movement coordination depends on intact proprioception. We hypothesized that adult stutterers would show deficient jaw-phonatory coordination relative to control participants. The task required initiation of phonation as a jaw-opening movement passed through a narrow spatial target. Target amplitude and jaw movement speed were varied. The stuttering group showed significantly higher movement error and spatial variability in jaw-phonatory coordination compared to the control group, but group differences in movement velocity or duration were not found. The aberrant jaw-phonatory coordination of the stuttering participants suggests that stuttering is associated with an oral proprioceptive limitation, although, the findings are also consistent with a motor control deficit. As a result of this activity, reader will (1) learn about a hypothesis and evidence supporting the view that a sensorimotor deficit contributes to chronic developmental stuttering and (2) will obtain information about the role of proprioception in multi-articulatory coordination and how it can be tested using an oral-phonatory coordination task.

A Window of Opportunity for Cognitive Training in Adolescence

PubMed Central

Knoll, Lisa J.; Fuhrmann, Delia; Sakhardande, Ashok L.; Stamp, Fabian; Speekenbrink, Maarten; Blakemore, Sarah-Jayne

2016-01-01

In the current study, we investigated windows for enhanced learning of cognitive skills during adolescence. Six hundred thirty-three participants (11–33 years old) were divided into four age groups, and each participant was randomly allocated to one of three training groups. Each training group completed up to 20 days of online training in numerosity discrimination (i.e., discriminating small from large numbers of objects), relational reasoning (i.e., detecting abstract relationships between groups of items), or face perception (i.e., identifying differences in faces). Training yielded some improvement in performance on the numerosity-discrimination task, but only in older adolescents or adults. In contrast, training in relational reasoning improved performance on that task in all age groups, but training benefits were greater for people in late adolescence and adulthood than for people earlier in adolescence. Training did not increase performance on the face-perception task for any age group. Our findings suggest that for certain cognitive skills, training during late adolescence and adulthood yields greater improvement than training earlier in adolescence, which highlights the relevance of this late developmental stage for education. PMID:27815519

Patterns of anomalies of structures of the middle ear and the facial nerve as revealed in newborn temporal bones.

PubMed

Tóth, Miklós; Sirirattanapan, Jarinratn; Mann, Wolf

2013-08-01

The purpose of this study is to offer new data about facial nerve malformations in the tympanic cavity. Prospective anatomic study of newborns to demonstrate the submacroscopic anatomy of the intratympanic facial nerve and its surrounding structures by malformations. Step-by-step microdissection of 12 newborn temporal bones and histologic evaluation of 4 middle ears showing multiple malformations. Four of 12 temporal bones presented malformation in the middle ear. All 4 temporal bones showed developmental failures of the stapes, and 3 of them had malposition of the tympanic portion of the facial nerve. In 3 cases, there was an oval window atresia, and in 1 case, the rim of the oval window was not ossified and was positioned medial to the stapes. Malformation or displacement of the stapes can be an indirect sign for facial nerve malformation. The most common site for facial nerve malformation is the tympanic portion. The tympanic segment of the nerve is devoid of bony covering in association with these anomalies of the stapes.

"Not just little adults": qualitative methods to support the development of pediatric patient-reported outcomes.

PubMed

Arbuckle, Rob; Abetz-Webb, Linda

2013-01-01

The US FDA and the European Medicines Agency (EMA) have issued incentives and laws mandating clinical research in pediatrics. While guidances for the development and validation of patient-reported outcomes (PROs) or health-related quality of life (HRQL) measures have been issued by these agencies, little attention has focused on pediatric PRO development methods. With reference to the literature, this article provides an overview of specific considerations that should be made with regard to the development of pediatric PRO measures, with a focus on performing qualitative research to ensure content validity. Throughout the questionnaire development process it is critical to use developmentally appropriate language and techniques to ensure outcomes have content validity, and will be reliable and valid within narrow age bands (0-2, 3-5, 6-8, 9-11, 12-14, 15-17 years). For qualitative research, sample sizes within those age bands must be adequate to demonstrate saturation while taking into account children's rapid growth and development. Interview methods, interview guides, and length of interview must all take developmental stage into account. Drawings, play-doh, or props can be used to engage the child. Care needs to be taken during cognitive debriefing, where repeated questioning can lead a child to change their answers, due to thinking their answer is incorrect. For the PROs themselves, the greatest challenge is in measuring outcomes in children aged 5-8 years. In this age range, while self-report is generally more valid, parent reports of observable behaviors are generally more reliable. As such, 'team completion' or a parent-administered child report is often the best option for children aged 5-8 years. For infants and very young children (aged 0-4 years), patient rating of observable behaviors is necessary, and, for adolescents and children aged 9 years and older, self-reported outcomes are generally valid and reliable. In conclusion, the development of PRO measures for use in children requires careful tailoring of qualitative methods, and performing research within narrow age bands. The best reporter should be carefully considered dependent on the child's age, developmental ability, and the concept being measured, and team completion should be considered alongside self-completion and observer measures.

The effect of a nonanatomic repair of the meniscal horn attachment on meniscal tension: a biomechanical study.

PubMed

Stärke, Christian; Kopf, Sebastian; Gröbel, Karl-Heinz; Becker, Roland

2010-03-01

The purpose of this biomechanical study was to investigate the potential effect of a nonanatomic repair of the meniscal horn attachment on the resultant circumferential tension in a large animal model and to show that the circumferential tension of the meniscus affects the local stress of the cartilage. All investigations were done in the medial compartment of porcine knees. First, the anterior horn attachment of the meniscus was mechanically separated from the surrounding tibial bone and fitted with a force transducer (n = 8). The femorotibial joint was loaded in compression at different flexion angles, and the resultant tension at the horn attachment was recorded. The measurements were done with the horn attachment at its anatomic position and repeated with the horn attachment being displaced medially or laterally by 3 mm. In the second part the local deformation of the cartilage under a femorotibial compressive load was measured at different levels of meniscal hoop tension (n = 5). A nonanatomic position of the horn attachment had a significant effect on the resultant tension (P < .01). Placing the horn attachment 3 mm medially decreased the tension at the horn attachment by 49% to 73%, depending on flexion angle and femorotibial load. The opposite placement resulted in a relative increase in the tension by 28% to 68%. Lower levels of meniscal hoop tension caused increased deformation of the cartilage (P < .05), indicating increased local stress. A nonanatomic position of the horn attachment strongly affects conversion of femorotibial loads into circumferential tension. There is a narrow window for a functionally sufficient repair of meniscal root tears. Although clinical inferences are limited because the specimens used were from a different species, there seems to be only a narrow window for a mechanically sufficient repair of root tears. Copyright 2010 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

The Anti-Methicillin-Resistant Staphylococcus aureus Quinolone WCK 771 Has Potent Activity against Sequentially Selected Mutants, Has a Narrow Mutant Selection Window against Quinolone-Resistant Staphylococcus aureus, and Preferentially Targets DNA Gyrase▿ †

PubMed Central

Bhagwat, Sachin S.; Mundkur, Lakshmi A.; Gupte, Shrikant V.; Patel, Mahesh V.; Khorakiwala, Habil F.

2006-01-01

WCK 771 is a broad-spectrum fluoroquinolone with enhanced activity against quinolone-resistant staphylococci. To understand the impact of the target-level interactions of WCK 771 on its antistaphylococcal pharmacodynamic properties, we determined the MICs for genetically defined mutants and studied the mutant prevention concentrations (MPCs), the frequency of mutation, and the cidality against the wild type and double mutants. There was a twofold increase in the MICs of WCK 771 for single gyrA mutants, indicating that DNA gyrase is its primary target. All first- and second-step mutants selected by WCK 771 revealed gyrA and grlA mutations, respectively. The MICs of WCK 771 and clinafloxacin were found to be superior to those of other quinolones against strains with double and triple mutations. WCK 771 was also cidal for high-density double mutants at low concentrations. WCK 771 and clinafloxacin showed narrow mutant selection windows compared to those of the other quinolones. Against a panel of 50 high-level quinolone-resistant clinical isolates of staphylococci (ciprofloxacin MIC ≥ 16 μg/ml), the WCK 771 MPCs were ≤2 μg/ml for 68% of the strains and ≤4 μg/ml for 28% of the strains. Our results demonstrate that gyrA is the primary target of WCK 771 and that it has pharmacodynamic properties remarkably different from those of quinolones with dual targets (garenoxacin and moxifloxacin) and topoisomerase IV-specific quinolones (trovafloxacin). WCK 771 displayed an activity profile comparable to that of clinafloxacin, a dual-acting quinolone with a high affinity to DNA gyrase. Overall, the findings signify the key role of DNA gyrase in determining the optimal antistaphylococcal features of quinolones. PMID:16940059

Development of a Novel Floating In-situ Gelling System for Stomach Specific Drug Delivery of the Narrow Absorption Window Drug Baclofen.

PubMed

R Jivani, Rishad; N Patel, Chhagan; M Patel, Dashrath; P Jivani, Nurudin

2010-01-01

The present study deals with development of a floating in-situ gel of the narrow absorption window drug baclofen. Sodium alginate-based in-situ gelling systems were prepared by dissolving various concentrations of sodium alginate in deionized water, to which varying concentrations of drug and calcium bicarbonate were added. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to check the presence of any interaction between the drug and the excipients. A 3(2) full factorial design was used for optimization. The concentrations of sodium alginate (X1) and calcium bicarbonate (X2) were selected as the independent variables. The amount of the drug released after 1 h (Q1) and 10 h (Q10) and the viscosity of the solution were selected as the dependent variables. The gels were studied for their viscosity, in-vitro buoyancy and drug release. Contour plots were drawn for each dependent variable and check-point batches were prepared in order to get desirable release profiles. The drug release profiles were fitted into different kinetic models. The floating lag time and floating time found to be 2 min and 12 h respectively. A decreasing trend in drug release was observed with increasing concentrations of CaCO3. The computed values of Q1 and Q10 for the check-point batch were 25% and 86% respectively, compared to the experimental values of 27.1% and 88.34%. The similarity factor (f 2) for the check-point batch being 80.25 showed that the two dissolution profiles were similar. The drug release from the in-situ gel follows the Higuchi model, which indicates a diffusion-controlled release. A stomach specific in-situ gel of baclofen could be prepared using floating mechanism to increase the residence time of the drug in stomach and thereby increase the absorption.

Wavelet-based group and phase velocity measurements: Method

NASA Astrophysics Data System (ADS)

Yang, H. Y.; Wang, W. W.; Hung, S. H.

2016-12-01

Measurements of group and phase velocities of surface waves are often carried out by applying a series of narrow bandpass or stationary Gaussian filters localized at specific frequencies to wave packets and estimating the corresponding arrival times at the peak envelopes and phases of the Fourier spectra. However, it's known that seismic waves are inherently nonstationary and not well represented by a sum of sinusoids. Alternatively, a continuous wavelet transform (CWT) which decomposes a time series into a family of wavelets, translated and scaled copies of a generally fast oscillating and decaying function known as the mother wavelet, is capable of retaining localization in both the time and frequency domain and well-suited for the time-frequency analysis of nonstationary signals. Here we develop a wavelet-based method to measure frequency-dependent group and phase velocities, an essential dataset used in crust and mantle tomography. For a given time series, we employ the complex morlet wavelet to obtain the scalogram of amplitude modulus |Wg| and phase φ on the time-frequency plane. The instantaneous frequency (IF) is then calculated by taking the derivative of phase with respect to time, i.e., (1/2π)dφ(f, t)/dt. Time windows comprising strong energy arrivals to be measured can be identified by those IFs close to the frequencies with the maximum modulus and varying smoothly and monotonically with time. The respective IFs in each selected time window are further interpolated to yield a smooth branch of ridge points or representative IFs at which the arrival time, tridge(f), and phase, φridge(f), after unwrapping and correcting cycle skipping based on a priori knowledge of the possible velocity range, are determined for group and phase velocity estimation. We will demonstrate our measurement method using both ambient noise cross correlation functions and multi-mode surface waves from earthquakes. The obtained dispersion curves will be compared with those by a conventional narrow bandpass method.

Controlling Surface Morphology and Circumventing Secondary Phase Formation in Non-polar m-GaN by Tuning Nitrogen Activity

NASA Astrophysics Data System (ADS)

Chang, C. W.; Wadekar, P. V.; Guo, S. S.; Cheng, Y. J.; Chou, M.; Huang, H. C.; Hsieh, W. C.; Lai, W. C.; Chen, Q. Y.; Tu, L. W.

2018-01-01

For the development of non-polar nitrides based optoelectronic devices, high-quality films with smooth surfaces, free of defects or clusters, are critical. In this work, the mechanisms governing the topography and single phase epitaxy of non-polar m-plane gallium nitride ( m-GaN) thin films are studied. The samples were grown using plasma-assisted molecular beam epitaxy on m-plane sapphire substrates. Growth of pure m-GaN thin films, concomitant with smooth surfaces is possible at low radio frequency powers and high growth temperatures as judged by the high resolution x-ray diffraction, field emission scanning electron microscopy, and atomic force microscopy measurements. Defect types and densities are quantified using transmission electron microscopy, while Raman spectroscopy was used to analyze the in-plane stress in the thin films which matches the lattice mismatch analysis. Energy dispersive spectroscopy and cathodoluminescence support a congruent growth and a dominant near band edge emission. From the analysis, a narrow growth window is discovered wherein epitaxial growth of pure m-plane GaN samples free of secondary phases with narrow rocking curves and considerable smooth surfaces are successfully demonstrated.

Slab narrowing in the Central Mediterranean: the Calabro-Ionian subduction zone as imaged by high resolution seismic tomography.

PubMed

Scarfì, L; Barberi, G; Barreca, G; Cannavò, F; Koulakov, I; Patanè, D

2018-03-26

A detailed 3D image of the Calabro-Ionian subduction system in the central Mediterranean was obtained by means of a seismic tomography, exploiting a large dataset of local earthquakes and computing algorithms able to build a dense grid of measure nodes. Results show that the slab is continuous below the southern sector of the Calabro-Peloritan Arc, but the deformation processes developing at its edges are leading to its progressive narrowing, influencing tectonics and magmatism at the surface, and with possible stress concentration in the tip zones. In the southwest, the deformation occurring at a free slab edge lead to propagation of a vertical lithospheric tear in the overriding plate, which extends along a NW-SE fault system (Aeolian-Tindari-Letojanni) up to about 30 km into the Ionian Sea; further southeast, the lithosphere appears only flexed and not broken yet. In the northeast, the slab seems to break progressively, parallel to the trench. Finally, northwest of Mt. Etna, the tomography highlights low V P that can be related to an upwelling of deep mantle material likely flowing laterally through a window opened by the complete slab detachment.

Pico-CSIA: Picomolar Scale Compound-Specific Isotope Analyses

NASA Astrophysics Data System (ADS)

Baczynski, A. A.; Polissar, P. J.; Juchelka, D.; Schwieters, J. B.; Hilkert, A.; Freeman, K. H.

2016-12-01

The basic approach to analyzing molecular isotopes has remained largely unchanged since the late 1990s. Conventional compound-specific isotope analyses (CSIA) are conducted using capillary gas chromatography (GC), a combustion interface, and an isotope-ratio mass spectrometer (IRMS). Commercially available GC-IRMS systems are comprised of components with inner diameters ≥0.25 mm and employ helium flow rates of 1-4 mL/min. These flow rates are an order of magnitude larger than what the IRMS can accept. Consequently, ≥90% of the sample is lost through the open split, and 1-10s of nanomoles of carbon are required for analysis. These sample requirements are prohibitive for many biomarkers, which are often present in picomolar concentrations. We utilize the resolving power and low flows of narrow-bore capillary GC to improve the sensitivity of CSIA. Narrow bore capillary columns (<0.25 mm ID) allow low helium flow rates of ≤0.5mL/min for more efficient sample transfer to the ion source of the IRMS while maintaining the high linear flow rates necessary to preserve narrow peak widths ( 250 ms). The IRMS has been fitted with collector amplifiers configured to 25 ms response times for rapid data acquisition across narrow peaks. Previous authors (e.g., Sacks et al., 2007) successfully demonstrated improved sensitivity afforded by narrow-bore GC columns. They reported an accuracy and precision of 1.4‰ for peaks with an average width at half maximum of 720 ms for 100 picomoles of carbon on column. Our method builds on their advances and further reduces peak widths ( 600 ms) and the amount of sample lost prior to isotopic analysis. Preliminary experiments with 100 picomoles of carbon on column show an accuracy and standard deviation <1‰. With further improvement, we hope to demonstrate robust isotopic analysis of 10s of picomoles of carbon, more than 2 orders of magnitude lower than commercial systems. The pico-CSIA method affords high-precision isotopic analyses for picomoles of carbon in organic biomarkers, which significantly lowers sample size requirements and broadens analytical windows in paleoclimate, astrobiological, and biogeochemical research.

Optimization of the Energy Window for PETbox4, a Preclinical PET Tomograph With a Small Inner Diameter

NASA Astrophysics Data System (ADS)

Gu, Z.; Bao, Q.; Taschereau, R.; Wang, H.; Bai, B.; Chatziioannou, A. F.

2014-06-01

Small animal positron emission tomography (PET) systems are often designed by employing close geometry configurations. Due to the different characteristics caused by geometrical factors, these tomographs require data acquisition protocols that differ from those optimized for conventional large diameter ring systems. In this work we optimized the energy window for data acquisitions with PETbox4, a 50 mm detector separation (box-like geometry) pre-clinical PET scanner, using the Geant4 Application for Tomographic Emission (GATE). The fractions of different types of events were estimated using a voxelized phantom including a mouse as well as its supporting chamber, mimicking a realistic mouse imaging environment. Separate code was developed to extract additional information about the gamma interactions for more accurate event type classification. Three types of detector backscatter events were identified in addition to the trues, phantom scatters and randoms. The energy window was optimized based on the noise equivalent count rate (NECR) and scatter fraction (SF) with lower-level discriminators (LLD) corresponding to energies from 150 keV to 450 keV. The results were validated based on the calculated image uniformity, spillover ratio (SOR) and recovery coefficient (RC) from physical measurements using the National Electrical Manufacturers Association (NEMA) NU-4 image quality phantom. These results indicate that when PETbox4 is operated with a more narrow energy window (350-650 keV), detector backscatter rejection is unnecessary. For the NEMA NU-4 image quality phantom, the SOR for the water chamber decreases by about 45% from 15.1% to 8.3%, and the SOR for the air chamber decreases by 31% from 12.0% to 8.3% at the LLDs of 150 and 350 keV, without obvious change in uniformity, further supporting the simulation based optimization. The optimization described in this work is not limited to PETbox4, but also applicable or helpful to other small inner diameter geometry scanners.

Neural correlates of perceptual narrowing in cross-species face-voice matching.

PubMed

Grossmann, Tobias; Missana, Manuela; Friederici, Angela D; Ghazanfar, Asif A

2012-11-01

Integrating the multisensory features of talking faces is critical to learning and extracting coherent meaning from social signals. While we know much about the development of these capacities at the behavioral level, we know very little about the underlying neural processes. One prominent behavioral milestone of these capacities is the perceptual narrowing of face-voice matching, whereby young infants match faces and voices across species, but older infants do not. In the present study, we provide neurophysiological evidence for developmental decline in cross-species face-voice matching. We measured event-related brain potentials (ERPs) while 4- and 8-month-old infants watched and listened to congruent and incongruent audio-visual presentations of monkey vocalizations and humans mimicking monkey vocalizations. The ERP results indicated that younger infants distinguished between the congruent and the incongruent faces and voices regardless of species, whereas in older infants, the sensitivity to multisensory congruency was limited to the human face and voice. Furthermore, with development, visual and frontal brain processes and their functional connectivity became more sensitive to the congruence of human faces and voices relative to monkey faces and voices. Our data show the neural correlates of perceptual narrowing in face-voice matching and support the notion that postnatal experience with species identity is associated with neural changes in multisensory processing (Lewkowicz & Ghazanfar, 2009). © 2012 Blackwell Publishing Ltd.

Narrowing the wingless-2 mutation to a 227 kb candidate region on chicken chromosome 12

PubMed Central

Webb, A E; Youngworth, I A; Kaya, M; Gitter, C L; O’Hare, E A; May, B; Cheng, H H; Delany, M E

2018-01-01

ABSTRACT Wingless-2 (wg-2) is an autosomal recessive mutation in chicken that results in an embryonic lethal condition. Affected individuals exhibit a multisystem syndrome characterized by absent wings, truncated legs, and craniofacial, kidney, and feather malformations. Previously, work focused on phenotype description, establishing the autosomal recessive pattern of Mendelian inheritance and placing the mutation on an inbred genetic background to create the congenic line UCD Wingless-2.331. The research described in this paper employed the complementary tools of breeding, genetics, and genomics to map the chromosomal location of the mutation and successively narrow the size of the region for analysis of the causative element. Specifically, the wg-2 mutation was initially mapped to a 7 Mb region of chromosome 12 using an Illumina 3 K SNP array. Subsequent SNP genotyping and exon sequencing combined with analysis from improved genome assemblies narrowed the region of interest to a maximum size of 227 kb. Within this region, 3 validated and 3 predicted candidate genes are found, and these are described. The wg-2 mutation is a valuable resource to contribute to an improved understanding of the developmental pathways involved in chicken and avian limb development as well as serving as a model for human development, as the resulting syndrome shares features with human congenital disorders. PMID:29562287

E/N effects on K0 values revealed by high precision measurements under low field conditions

NASA Astrophysics Data System (ADS)

Hauck, Brian C.; Siems, William F.; Harden, Charles S.; McHugh, Vincent M.; Hill, Herbert H.

2016-07-01

Ion mobility spectrometry (IMS) is used to detect chemical warfare agents, explosives, and narcotics. While IMS has a low rate of false positives, their occurrence causes the loss of time and money as the alarm is verified. Because numerous variables affect the reduced mobility (K0) of an ion, wide detection windows are required in order to ensure a low false negative response rate. Wide detection windows, however, reduce response selectivity, and interferents with similar K0 values may be mistaken for targeted compounds and trigger a false positive alarm. Detection windows could be narrowed if reference K0 values were accurately known for specific instrumental conditions. Unfortunately, there is a lack of confidence in the literature values due to discrepancies in the reported K0 values and their lack of reported error. This creates the need for the accurate control and measurement of each variable affecting ion mobility, as well as for a central accurate IMS database for reference and calibration. A new ion mobility spectrometer has been built that reduces the error of measurements affecting K0 by an order of magnitude less than ±0.2%. Precise measurements of ±0.002 cm2 V-1 s-1 or better have been produced and, as a result, an unexpected relationship between K0 and the electric field to number density ratio (E/N) has been discovered in which the K0 values of ions decreased as a function of E/N along a second degree polynomial trend line towards an apparent asymptote at approximately 4 Td.

Characterization of Raman Scattering in Solid Samples with Different Particle Sizes and Elucidation on the Trends of Particle Size-Dependent Intensity Variations in Relation to Changes in the Sizes of Laser Illumination and Detection Area.

PubMed

Duy, Pham K; Chun, Seulah; Chung, Hoeil

2017-11-21

We have systematically characterized Raman scatterings in solid samples with different particle sizes and investigated subsequent trends of particle size-induced intensity variations. For this purpose, both lactose powders and pellets composed of five different particle sizes were prepared. Uniquely in this study, three spectral acquisition schemes with different sizes of laser illuminations and detection windows were employed for the evaluation, since it was expected that the experimental configuration would be another factor potentially influencing the intensity of the lactose peak, along with the particle size itself. In both samples, the distribution of Raman photons became broader with the increase in particle size, as the mean free path of laser photons, the average photon travel distance between consecutive scattering locations, became longer under this situation. When the particle size was the same, the Raman photon distribution was narrower in the pellets since the individual particles were more densely packed in a given volume (the shorter mean free path). When the size of the detection window was small, the number of photons reaching the detector decreased as the photon distribution was larger. Meanwhile, a large-window detector was able to collect the widely distributed Raman photons more effectively; therefore, the trends of intensity change with the variation in particle size were dissimilar depending on the employed spectral acquisition schemes. Overall, the Monte Carlo simulation was effective at probing the photon distribution inside the samples and helped to support the experimental observations.

Ecological Consequences of Shifting the Timing of Burning Tallgrass Prairie

PubMed Central

Towne, E. Gene; Craine, Joseph M.

2014-01-01

In the Kansas Flint Hills, grassland burning is conducted during a relatively narrow window because management recommendations for the past 40 years have been to burn only in late spring. Widespread prescribed burning within this restricted time frame frequently creates smoke management issues downwind. A potential remedy for the concentrated smoke production in late spring is to expand burning to times earlier in the year. Yet, previous research suggested that burning in winter or early spring reduces plant productivity and cattle weight gain while increasing the proportion of undesirable plant species. In order to better understand the ecological consequences of burning at different times of the year, plant production and species abundance were measured for 20 years on ungrazed watersheds burned annually in autumn, winter, or spring. We found that there were no significant differences in total grass production among the burns on either upland or lowland topographic positions, although spring burned watersheds had higher grass culm production and lower forb biomass than autumn and winter burned watersheds. Burning in autumn or winter broadened the window of grass productivity response to precipitation, which reduces susceptibility to mid-season drought. Burning in autumn or winter also increased the phenological range of species by promoting cool-season graminoids without a concomitant decrease in warm-season grasses, potentially widening the seasonal window of high-quality forage. Incorporating autumn and winter burns into the overall portfolio of tallgrass prairie management should increase the flexibility in managing grasslands, promote biodiversity, and minimize air quality issues caused by en masse late-spring burning with little negative consequences for cattle production. PMID:25077487

Ecological consequences of shifting the timing of burning tallgrass prairie.

PubMed

Towne, E Gene; Craine, Joseph M

2014-01-01

In the Kansas Flint Hills, grassland burning is conducted during a relatively narrow window because management recommendations for the past 40 years have been to burn only in late spring. Widespread prescribed burning within this restricted time frame frequently creates smoke management issues downwind. A potential remedy for the concentrated smoke production in late spring is to expand burning to times earlier in the year. Yet, previous research suggested that burning in winter or early spring reduces plant productivity and cattle weight gain while increasing the proportion of undesirable plant species. In order to better understand the ecological consequences of burning at different times of the year, plant production and species abundance were measured for 20 years on ungrazed watersheds burned annually in autumn, winter, or spring. We found that there were no significant differences in total grass production among the burns on either upland or lowland topographic positions, although spring burned watersheds had higher grass culm production and lower forb biomass than autumn and winter burned watersheds. Burning in autumn or winter broadened the window of grass productivity response to precipitation, which reduces susceptibility to mid-season drought. Burning in autumn or winter also increased the phenological range of species by promoting cool-season graminoids without a concomitant decrease in warm-season grasses, potentially widening the seasonal window of high-quality forage. Incorporating autumn and winter burns into the overall portfolio of tallgrass prairie management should increase the flexibility in managing grasslands, promote biodiversity, and minimize air quality issues caused by en masse late-spring burning with little negative consequences for cattle production.

Environmental and epigenetic effects upon preimplantation embryo metabolism and development

PubMed Central

Chason, Rebecca J; Csokmay, John; Segars, James H.; DeCherney, Alan H.; Armant, D. Randall

2011-01-01

In vitro fertilization has provided a unique window into the metabolic processes that drive embryonic growth and development from a fertilized ovum to a competent blastocyst. Post-fertilization development is dependent upon a dramatic reshuffling of the parental genomes during meiosis, as well as epigenetic changes that provide a new and autonomous set of instructions to guide cellular differentiation both in the embryo and beyond. While early literature focused simply on the substrates and culture conditions required for progress through embryonic development, more recent insights lead us to suggest that the surrounding environment can alter the epigenome, which can, in turn, impact embryonic metabolism and developmental competence. PMID:21741268

Subtractive and differential hybridization molecular analyses of Ceratitis capitata XX/XY versus XX embryos to search for male-specific early transcribed genes.

PubMed

Salvemini, Marco; D'Amato, Rocco; Petrella, Valeria; Ippolito, Domenica; Ventre, Giuseppe; Zhang, Ying; Saccone, Giuseppe

2014-01-01

The agricultural pest Ceratitis capitata, also known as the Mediterranean fruit fly or Medfly, is a fruit crop pest of very high economic relevance in different continents. The strategy to separate Ceratitis males from females (sexing) in mass rearing facilities is a useful step before the sterilization and release of male-only flies in Sterile Insect Technique control programs (SIT). The identification of genes having early embryonic male-specific expression, including Y-linked genes, such as the Maleness factor, could help to design novel and improved methods of sexing in combination with transgenesis, aiming to confer conditional female-specific lethality or female-to-male sexual reversal. We used a combination of Suppression Subtractive Hybrydization (SSH), Mirror Orientation Selection (MOS) anddifferential screening hybridization (DSH) techniques to approach the problem of isolating corresponding mRNAs expressed in XX/XY embryos versus XX-only embryos during a narrow developmental window (8-10 hours after egg laying, AEL ). Here we describe a novel strategy we have conceived to obtain relatively large amounts of XX-only embryos staged at 8-10 h AEL and so to extract few micrograms of polyA+ required to apply the complex technical procedure. The combination of these 3 techniques led to the identification of a Y-linked putative gene, CcGm2, sharing high sequence identity to a paralogous gene, CcGm1, localized either on an autosome or on the X chromosome. We propose that CcGm2 is a first interesting putative Y-linked gene which could play a role in sex determination. The function exterted by this gene should be investigated by novel genetic tools, such as CRISPR-CAS9, which will permit to target only the Y-linked paralogue, avoiding to interfere with the autosomal or X-linked paralogue function.

Subtractive and differential hybridization molecular analyses of Ceratitis capitata XX/XY versus XX embryos to search for male-specific early transcribed genes

PubMed Central

2014-01-01

The agricultural pest Ceratitis capitata, also known as the Mediterranean fruit fly or Medfly, is a fruit crop pest of very high economic relevance in different continents. The strategy to separate Ceratitis males from females (sexing) in mass rearing facilities is a useful step before the sterilization and release of male-only flies in Sterile Insect Technique control programs (SIT). The identification of genes having early embryonic male-specific expression, including Y-linked genes, such as the Maleness factor, could help to design novel and improved methods of sexing in combination with transgenesis, aiming to confer conditional female-specific lethality or female-to-male sexual reversal. We used a combination of Suppression Subtractive Hybrydization (SSH), Mirror Orientation Selection (MOS) and differential screening hybridization (DSH) techniques to approach the problem of isolating corresponding mRNAs expressed in XX/XY embryos versus XX-only embryos during a narrow developmental window (8-10 hours after egg laying, AEL ). Here we describe a novel strategy we have conceived to obtain relatively large amounts of XX-only embryos staged at 8-10 h AEL and so to extract few micrograms of polyA+ required to apply the complex technical procedure. The combination of these 3 techniques led to the identification of a Y-linked putative gene, CcGm2, sharing high sequence identity to a paralogous gene, CcGm1, localized either on an autosome or on the X chromosome. We propose that CcGm2 is a first interesting putative Y-linked gene which could play a role in sex determination. The function exterted by this gene should be investigated by novel genetic tools, such as CRISPR-CAS9, which will permit to target only the Y-linked paralogue, avoiding to interfere with the autosomal or X-linked paralogue function. PMID:25472628

Redox-mediated quorum sensing in plants.

PubMed

Fuller, Alexandra W; Young, Phoebe; Pierce, B Daniel; Kitson-Finuff, Jamie; Jain, Purvi; Schneider, Karl; Lazar, Stephen; Taran, Olga; Palmer, Andrew G; Lynn, David G

2017-01-01

The rhizosphere, the narrow zone of soil around plant roots, is a complex network of interactions between plants, bacteria, and a variety of other organisms. The absolute dependence on host-derived signals, or xenognosins, to regulate critical developmental checkpoints for host commitment in the obligate parasitic plants provides a window into the rhizosphere's chemical dynamics. These sessile intruders use H2O2 in a process known as semagenesis to chemically modify the mature root surfaces of proximal host plants and generate p-benzoquinones (BQs). The resulting redox-active signaling network regulates the spatial and temporal commitments necessary for host attachment. Recent evidence from non-parasites, including Arabidopsis thaliana, establishes that reactive oxygen species (ROS) production regulates similar redox circuits related to root recognition, broadening xenognosins' role beyond the parasites. Here we compare responses to the xenognosin dimethoxybenzoquinone (DMBQ) between the parasitic plant Striga asiatica and the non-parasitic A. thaliana. Exposure to DMBQ simulates the proximity of a mature root surface, stimulating an increase in cytoplasmic Ca2+ concentration in both plants, but leads to remarkably different phenotypic responses in the parasite and non-parasite. In S. asiatica, DMBQ induces development of the host attachment organ, the haustorium, and decreases ROS production at the root tip, while in A. thaliana, ROS production increases and further growth of the root tip is arrested. Obstruction of Ca2+ channels and the addition of antioxidants both lead to a decrease in the DMBQ response in both parasitic and non-parasitic plants. These results are consistent with Ca2+ regulating the activity of NADPH oxidases, which in turn sustain the autocatalytic production of ROS via an external quinone/hydroquinone redox cycle. Mechanistically, this chemistry is similar to black and white photography with the emerging dynamic reaction-diffusion network laying the foundation for the precise temporal and spatial control underlying rhizosphere architecture.

Developmental abnormalities of the occipital bone in human chondrodystrophies (achondroplasia and thanatophoric dwarfism).

PubMed

Marin-Padilla, M; Marin-Padilla, T M

1977-01-01

Specific developmental malformations have been demonstrated in the occipital bone of two chondrodysplastic disorders (achondroplasia and thanatophoric dwarfism). Analysis of these malformations indicates that the occipital bone is primary affected in these disorders. In both cases, the endochondral-derived components of the occipital bone (the basioccipital, the two lateral parts, and the planum nuchale of the squama occipitalis) have failed to grow properly and are smaller and shorter than normal. On the other hand, the planum occipitalis of the squama, which derives from intramembranous ossification, is unaffected. In addition, the nature of these abnormalities indicates that the occipital synchondroses, together with the epiphyseal plates of other bones, are primarily affected in these two chondrodysplasias. The components of the occipital bone formed between the affected synchondroses failed to grow normally. The resulting malformation of the occipital bone is undoubtedly the cause of the shortening of the posterior cerebral fossa and of the considerable narrowing of the foramen magnum often described in these chondrodysplasias. It is postulated that growth disturbances between the affected occipital bone and the unaffected central nervous system results in the inadequacy of the posterior cerebral fossa and the foramen magnum to accommodate the growing brain. Consequently, compression of the brain at the posterior cerebral fossa or the foramen magnum levels could occur and thus lead to neurologic complications such as hydrocephalus and compression of the brain stem. It is suggested that the surgical removal of the fused posterior border of the lateral parts of the occipital bone (partial nuchalectomy) for the purpose of enlarging the narrow foramen magnum may be indicated in those chondrodysplastic children who develop these types of neurologic complications.

Socioeconomic status and executive function: developmental trajectories and mediation.

PubMed

Hackman, Daniel A; Gallop, Robert; Evans, Gary W; Farah, Martha J

2015-09-01

Childhood socioeconomic status (SES) predicts executive function (EF), but fundamental aspects of this relation remain unknown: the developmental course of the SES disparity, its continued sensitivity to SES changes during that course, and the features of childhood experience responsible for the SES-EF relation. Regarding course, early disparities would be expected to grow during development if caused by accumulating stressors at a given constant level of SES. Alternatively, they would narrow if schooling partly compensates for the effects of earlier deprivation, allowing lower-SES children to 'catch up'. The potential for later childhood SES change to affect EF is also unknown. Regarding mediating factors, previous analyses produced mixed answers, possibly due to correlation amongst candidate mediators. We address these issues with measures of SES, working memory and planning, along with multiple candidate mediators, from the NICHD Study of Early Childcare (n = 1009). Early family income-to-needs and maternal education predicted planning by first grade, and income-to-needs predicted working memory performance at 54 months. Effects of early SES remained consistent through middle childhood, indicating that the relation between early indicators of SES and EF emerges in childhood and persists without narrowing or widening across early and middle childhood. Changes in family income-to-needs were associated with significant changes in planning and trend-level changes in working memory. Mediation analyses supported the role of early childhood home characteristics in explaining the association between SES and EF, while early childhood maternal sensitivity was specifically implicated in the association between maternal education and planning. Early emerging and persistent SES-related differences in EF, partially explained by characteristics of the home and family environment, are thus a potential source of socioeconomic disparities in achievement and health across development. © 2015 John Wiley & Sons Ltd.

Dipole-Induced Electromagnetic Transparency

NASA Astrophysics Data System (ADS)

Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric

2014-10-01

We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that, in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a dipole-induced electromagnetic transparency (DIET) regime, similar to electromagnetically induced transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed.

Structure and enhanced thermochromic performance of low-temperature fabricated VO2/V2O3 thin film

NASA Astrophysics Data System (ADS)

Sun, Guangyao; Cao, Xun; Gao, Xiang; Long, Shiwei; Liang, Mengshi; Jin, Ping

2016-10-01

For VO2-based smart window manufacture, it is a long-standing demand for high-quality thin films deposited at low temperature. Here, the thermochromic films of VO2 were deposited by a magnetron sputtering method at a fairly low temperature of 250 °C without subsequent annealing by embedding a V2O3 interlayer. V2O3 acts as a seed layer to lower the depositing temperature and buffer layer to epitaxial grow VO2 film. The VO2/V2O3 films display high solar modulating ability and narrow hysteresis loop. Our data can serve as a promising point for industrial production with high degree of crystallinity at a low temperature.

Seismology and geodesy of the sun: Low-frequency oscillations.

PubMed

Dicke, R H

1981-04-01

The hourly averages of the solar ellipticity measured from June 13 to Sept. 17, 1966, are analyzed for indications of solar oscillations with periods in excess of 2 hr nu < 0.5 hr(-1). Nothing significant is found for frequencies nu > 0.1 hr(-1) but for lower frequencies the power spectrum shows a very complex structure containing about 20 strong narrow peaks. The complexity is illusionary. The signal apparently consists of only two frequencies. The complexity is due to aliasing by the window function with its basic 24-hr period, with many observational days missing, and with different numbers of hourly averages for the various observational days. Both signal frequencies are apparently due to odd-degree spherical harmonic oscillations of the sun.

Methanol ice in the protostar GL 2136

NASA Technical Reports Server (NTRS)

Skinner, C. J.; Tielens, A. G. G. M.; Barlow, M. J.; Justtanont, K.

1992-01-01

We present ground-based spectra in the 10 and 20 micron atmospheric windows of the deeply embedded protostar GL 2136. These reveal narrow absorption features at 9.7 and 8.9 microns, which we ascribe to the CO-stretch and CH3 rock (respectively) of solid methanol in grain mantles. The peak position of the 9.7 micron band implies that methanol is an important ice mantle component. However, the CH3OH/H2O abundance ratio derived from the observed column densities is only 0.1. This discrepancy suggests that the solid methanol and water ice are located in independent grain components. These independent components may reflect chemical differentiation during grain mantle formation and/or partial outgassing close to the protostar.

Potential of Surface Enhanced Raman Spectroscopy (SERS) in Therapeutic Drug Monitoring (TDM). A Critical Review

PubMed Central

Jaworska, Aleksandra; Fornasaro, Stefano; Sergo, Valter; Bonifacio, Alois

2016-01-01

Surface-Enhanced Raman Spectroscopy (SERS) is a label-free technique that enables quick monitoring of substances at low concentrations in biological matrices. These advantages make it an attractive tool for the development of point-of-care tests suitable for Therapeutic Drug Monitoring (TDM) of drugs with a narrow therapeutic window, such as chemotherapeutic drugs, immunosuppressants, and various anticonvulsants. In this article, the current applications of SERS in the field of TDM for cancer therapy are discussed in detail and illustrated according to the different strategies and substrates. In particular, future perspectives are provided and special concerns regarding the standardization of self-assembly methods and nanofabrication procedures, quality assurance, and technology readiness are critically evaluated. PMID:27657146

Multiple-taper spectral analysis: A stand-alone C-subroutine

NASA Astrophysics Data System (ADS)

Lees, Jonathan M.; Park, Jeffrey

1995-03-01

A simple set of subroutines in ANSI-C are presented for multiple taper spectrum estimation. The multitaper approach provides an optimal spectrum estimate by minimizing spectral leakage while reducing the variance of the estimate by averaging orthogonal eigenspectrum estimates. The orthogonal tapers are Slepian nπ prolate functions used as tapers on the windowed time series. Because the taper functions are orthogonal, combining them to achieve an average spectrum does not introduce spurious correlations as standard smoothed single-taper estimates do. Furthermore, estimates of the degrees of freedom and F-test values at each frequency provide diagnostics for determining levels of confidence in narrow band (single frequency) periodicities. The program provided is portable and has been tested on both Unix and Macintosh systems.

Self-organized pattern formation at organic-inorganic interfaces during deposition: Experiment versus modeling

NASA Astrophysics Data System (ADS)

Szillat, F.; Mayr, S. G.

2011-09-01

Self-organized pattern formation during physical vapor deposition of organic materials onto rough inorganic substrates is characterized by a complex morphological evolution as a function of film thickness. We employ a combined experimental-theoretical study using atomic force microscopy and numerically solved continuum rate equations to address morphological evolution in the model system: poly(bisphenol A carbonate) on polycrystalline Cu. As the key ingredients for pattern formation, (i) curvature and interface potential driven surface diffusion, (ii) deposition noise, and (iii) interface boundary effects are identified. Good agreement of experiments and theory, fitting only the Hamaker constant and diffusivity within narrow physical parameter windows, corroborates the underlying physics and paves the way for computer-assisted interface engineering.

Sensitivity of hiPSC-derived neural stem cells (NSC) to Pyrroloquinoline quinone depends on their developmental stage.

PubMed

Augustyniak, J; Lenart, J; Zychowicz, M; Lipka, G; Gaj, P; Kolanowska, M; Stepien, P P; Buzanska, L

2017-12-01

Pyrroloquinoline quinone (PQQ) is a factor influencing on the mitochondrial biogenesis. In this study the PQQ effect on viability, total cell number, antioxidant capacity, mitochondrial biogenesis and differentiation potential was investigated in human induced Pluripotent Stem Cells (iPSC) - derived: neural stem cells (NSC), early neural progenitors (eNP) and neural progenitors (NP). Here we demonstrated that sensitivity to PQQ is dependent upon its dose and neural stage of development. Induction of the mitochondrial biogenesis by PQQ at three stages of neural differentiation was evaluated at mtDNA, mRNA and protein level. Changes in NRF1, TFAM and PPARGC1A gene expression were observed at all developmental stages, but only at eNP were correlated with the statistically significant increase in the mtDNA copy numbers and enhancement of SDHA, COX-1 protein level. Thus, the "developmental window" of eNP for PQQ-evoked mitochondrial biogenesis is proposed. This effect was independent of high antioxidant capacity of PQQ, which was confirmed in all tested cell populations, regardless of the stage of hiPSC neural differentiation. Furthermore, a strong induction of GFAP, with down regulation of MAP2 gene expression upon PQQ treatment was observed. This indicates a possibility of shifting the balance of cell differentiation in the favor of astroglia, but more research is needed at this point. Copyright © 2017 Elsevier Ltd. All rights reserved.

The neurite growth inhibitory effects of soluble TNFα on developing sympathetic neurons are dependent on developmental age.

PubMed

Nolan, Aoife M; Collins, Louise M; Wyatt, Sean L; Gutierrez, Humberto; O'Keeffe, Gerard W

2014-01-01

During development, the growth of neural processes is regulated by an array of cellular and molecular mechanisms which influence growth rate, direction and branching. Recently, many members of the TNF superfamily have been shown to be key regulators of neurite growth during development. The founder member of this family, TNFα can both promote and inhibit neurite growth depending on the cellular context. Specifically, transmembrane TNFα promotes neurite growth, while soluble TNFα inhibits it. While the growth promoting effects of TNFα are restricted to a defined developmental window of early postnatal development, whether the growth inhibitory effects of soluble TNFα occur throughout development is unknown. In this study we used the extensively studied, well characterised neurons of the superior cervical ganglion to show that the growth inhibitory effects of soluble TNFα are restricted to a specific period of late embryonic and early postnatal development. Furthermore, we show that this growth inhibitory effect of soluble TNFα requires NF-κB signalling at all developmental stages at which soluble TNFα inhibits neurite growth. These findings raise the possibility that increases in the amount of soluble TNFα in vivo, for example as a result of maternal inflammation, could negatively affect neurite growth in developing neurons at specific stages of development. Copyright © 2015 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

Individual differences in frontolimbic circuitry and anxiety emerge with adolescent changes in endocannabinoid signaling across species.

PubMed

Gee, Dylan G; Fetcho, Robert N; Jing, Deqiang; Li, Anfei; Glatt, Charles E; Drysdale, Andrew T; Cohen, Alexandra O; Dellarco, Danielle V; Yang, Rui R; Dale, Anders M; Jernigan, Terry L; Lee, Francis S; Casey, B J

2016-04-19

Anxiety disorders peak in incidence during adolescence, a developmental window that is marked by dynamic changes in gene expression, endocannabinoid signaling, and frontolimbic circuitry. We tested whether genetic alterations in endocannabinoid signaling related to a common polymorphism in fatty acid amide hydrolase (FAAH), which alters endocannabinoid anandamide (AEA) levels, would impact the development of frontolimbic circuitry implicated in anxiety disorders. In a pediatric imaging sample of over 1,000 3- to 21-y-olds, we show effects of the FAAH genotype specific to frontolimbic connectivity that emerge by ∼12 y of age and are paralleled by changes in anxiety-related behavior. Using a knock-in mouse model of the FAAH polymorphism that controls for genetic and environmental backgrounds, we confirm phenotypic differences in frontoamygdala circuitry and anxiety-related behavior by postnatal day 45 (P45), when AEA levels begin to decrease, and also, at P75 but not before. These results, which converge across species and level of analysis, highlight the importance of underlying developmental neurobiology in the emergence of genetic effects on brain circuitry and function. Moreover, the results have important implications for the identification of risk for disease and precise targeting of treatments to the biological state of the developing brain as a function of developmental changes in gene expression and neural circuit maturation.

Transient activation of dopaminergic neurons during development modulates visual responsiveness, locomotion and brain activity in a dopamine ontogeny model of schizophrenia.

PubMed

Calcagno, B; Eyles, D; van Alphen, B; van Swinderen, B

2013-01-08

It has been observed that certain developmental environmental risk factors for schizophrenia when modeled in rodents alter the trajectory of dopaminergic development, leading to persistent behavioural changes in adults. This has recently been articulated as the "dopamine ontogeny hypothesis of schizophrenia". To test one aspect of this hypothesis, namely that transient dopaminergic effects during development modulate attention-like behavior and arousal in adults, we turned to a small-brain model, Drosophila melanogaster. By applying genetic tools allowing transient activation or silencing of dopaminergic neurons in the fly brain, we investigated whether a critical window exists during development when altered dopamine (DA) activity levels could lead to impairments in arousal states in adult animals. We found that increased activity in dopaminergic neurons in later stages of development significantly increased visual responsiveness and locomotion, especially in adult males. This misallocation of visual salience and hyperactivity mimicked the effect of acute methamphetamine feeding to adult flies, suggesting up-regulated DA signaling could result from developmental manipulations. Finally, brain recordings revealed significantly reduced gamma-band activity in adult animals exposed to the transient developmental insult. Together, these data support the idea that transient alterations in DA signaling during development can permanently alter behavior in adults, and that a reductionist model such as Drosophila can be used to investigate potential mechanisms underlying complex cognitive disorders such as schizophrenia.

Understanding mental retardation in Down's syndrome using trisomy 16 mouse models.

PubMed

Galdzicki, Z; Siarey, R J

2003-06-01

Mental retardation in Down's syndrome, human trisomy 21, is characterized by developmental delays, language and memory deficits and other cognitive abnormalities. Neurophysiological and functional information is needed to understand the mechanisms of mental retardation in Down's syndrome. The trisomy mouse models provide windows into the molecular and developmental effects associated with abnormal chromosome numbers. The distal segment of mouse chromosome 16 is homologous to nearly the entire long arm of human chromosome 21. Therefore, mice with full or segmental trisomy 16 (Ts65Dn) are considered reliable animal models of Down's syndrome. Ts65Dn mice demonstrate impaired learning in spatial tests and abnormalities in hippocampal synaptic plasticity. We hypothesize that the physiological impairments in the Ts65Dn mouse hippocampus can model the suboptimal brain function occuring at various levels of Down's syndrome brain hierarchy, starting at a single neuron, and then affecting simple and complex neuronal networks. Once these elements create the gross brain structure, their dysfunctional activity cannot be overcome by extensive plasticity and redundancy, and therefore, at the end of the maturation period the mind inside this brain remains deficient and delayed in its capabilities. The complicated interactions that govern this aberrant developmental process cannot be rescued through existing compensatory mechanisms. In summary, overexpression of genes from chromosome 21 shifts biological homeostasis in the Down's syndrome brain to a new less functional state.

Developmental changes in automatic rule-learning mechanisms across early childhood.

PubMed

Mueller, Jutta L; Friederici, Angela D; Männel, Claudia

2018-06-27

Infants' ability to learn complex linguistic regularities from early on has been revealed by electrophysiological studies indicating that 3-month-olds, but not adults, can automatically detect non-adjacent dependencies between syllables. While different ERP responses in adults and infants suggest that both linguistic rule learning and its link to basic auditory processing undergo developmental changes, systematic investigations of the developmental trajectories are scarce. In the present study, we assessed 2- and 4-year-olds' ERP indicators of pitch discrimination and linguistic rule learning in a syllable-based oddball design. To test for the relation between auditory discrimination and rule learning, ERP responses to pitch changes were used as predictor for potential linguistic rule-learning effects. Results revealed that 2-year-olds, but not 4-year-olds, showed ERP markers of rule learning. Although, 2-year-olds' rule learning was not dependent on differences in pitch perception, 4-year-old children demonstrated a dependency, such that those children who showed more pronounced responses to pitch changes still showed an effect of rule learning. These results narrow down the developmental decline of the ability for automatic linguistic rule learning to the age between 2 and 4 years, and, moreover, point towards a strong modification of this change by auditory processes. At an age when the ability of automatic linguistic rule learning phases out, rule learning can still be observed in children with enhanced auditory responses. The observed interrelations are plausible causes for age-of-acquisition effects and inter-individual differences in language learning. © 2018 John Wiley & Sons Ltd.

Different Cranial Ontogeny in Europeans and Southern Africans

PubMed Central

Sardi, Marina L.; Ramírez Rozzi, Fernando V.

2012-01-01

Modern human populations differ in developmental processes and in several phenotypic traits. However, the link between ontogenetic variation and human diversification has not been frequently addressed. Here, we analysed craniofacial ontogenies by means of geometric-morphometrics of Europeans and Southern Africans, according to dental and chronological ages. Results suggest that different adult cranial morphologies between Southern Africans and Europeans arise by a combination of processes that involve traits modified during the prenatal life and others that diverge during early postnatal ontogeny. Main craniofacial changes indicate that Europeans differ from Southern Africans by increasing facial developmental rates and extending the attainment of adult size and shape. Since other studies have suggested that native subsaharan populations attain adulthood earlier than Europeans, it is probable that facial ontogeny is linked with other developmental mechanisms that control the timing of maturation in other variables. Southern Africans appear as retaining young features in adulthood. Facial ontogeny in Europeans produces taller and narrower noses, which seems as an adaptation to colder environments. The lack of these morphological traits in Neanderthals, who lived in cold environments, seems a paradox, but it is probably the consequence of a warm-adapted faces together with precocious maturation. When modern Homo sapiens migrated into Asia and Europe, colder environments might establish pressures that constrained facial growth and development in order to depart from the warm-adapted morphology. Our results provide some answers about how cranial growth and development occur in two human populations and when developmental shifts take place providing a better adaptation to environmental constraints. PMID:22558270

A Fluorescent Indicator for Imaging Lysosomal Zinc(II) with Förster Resonance Energy Transfer (FRET)-Enhanced Photostability and a Narrow Band of Emission

PubMed Central

Sreenath, Kesavapillai; Yuan, Zhao; Allen, John R.

2015-01-01

We demonstrate a strategy to transfer the zinc(II) sensitivity of a fluoroionophore with low photostability and a broad emission band to a bright and photostable fluorophore with a narrow emission band. The two fluorophores are covalently connected to afford an intramolecular Förster resonance energy transfer (FRET) conjugate. The FRET donor in the conjugate is a zinc(II)-sensitive arylvinylbipyridyl fluoroionophore, the absorption and emission of which undergo bathochromic shifts upon zinc(II) coordination. When the FRET donor is excited, efficient intramolecular energy transfer occurs to result in the emission of the acceptor boron dipyrromethene (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene or BODIPY) as a function of zinc(II) concentration. The broad emission band of the donor/zinc(II) complex is transformed into the strong, narrow emission band of the BODIPY acceptor in the FRET conjugates, which can be captured within the narrow emission window that is preferred for multicolor imaging experiments. In addition to competing with other nonradiative decay processes of the FRET donor, the rapid intramolecular FRET of the excited FRET-conjugate molecule protects the donor fluorophore from photobleaching, thus enhancing the photostability of the indicator. FRET conjugates 3 and 4 contain aliphatic amino groups, which selectively target lysosomes in mammalian cells. This subcellular localization preference was verified by using confocal fluorescence microscopy, which also shows the zinc(II)-enhanced emission of 3 and 4 in lysosomes. It was further shown using two-color structured illumination microscopy (SIM), which is capable of extending the lateral resolution over the Abbe diffraction limit by a factor of two, that the morpholino-functionalized compound 4 localizes in the interior of lysosomes, rather than anchoring on the lysosomal membranes, of live HeLa cells. PMID:25382395

Canadian Association of Emergency Physicians position statement on acute ischemic stroke.

PubMed

Harris, Devin; Hall, Christopher; Lobay, Kevin; McRae, Andrew; Monroe, Tanya; Perry, Jeffrey J; Shearing, Anthony; Wollam, Gabe; Goddard, Tom; Lang, Eddy

2015-03-01

The CAEP Stroke Practice Committee was convened in the spring of 2013 to revisit the 2001 policy statement on the use of thrombolytic therapy in acute ischemic stroke. The terms of reference of the panel were developed to include national representation from urban academic centres as well as community and rural centres from all regions of the country. Membership was determined by attracting recognized stroke leaders from across the country who agreed to volunteer their time towards the development of revised guidance on the topic. The guideline panel elected to adopt the GRADE language to communicate guidance after review of existing systematic reviews and international clinical practice guidelines. Stroke neurologists from across Canada were engaged to work alongside panel members to develop guidance as a dyad-based consensus when possible. There was no unique systematic review performed to support this guidance, rather existing efficacy data was relied upon. After a series of teleconferences and face to face meetings, a draft guideline was developed and presented to the CAEP board in June of 2014. The panel noted the development of significant new evidence to inform a number of clinical questions related to acute stroke management. In general terms the recommendations issued by the CAEP Stroke Practice Committee are supportive of the use of thrombolytic therapy when treatment can be administered within 3 hours of symptom onset. The committee is also supportive of system-level changes including pre-hospital interventions, the transport of patients to dedicated stroke centers when possible and tele-health measures to support thrombolytic therapy in a timely window. Of note, after careful deliberation, the panel elected to issue a conditional recommendation against the use of thrombolytic therapy in the 3–4.5 hour window. The view of the committee was that as a result of a narrow risk benefit balance, one that is considerably narrower than the same considerations under 3 hours, a significant number of informed patients and families would opt against the risk of early intracranial hemorrhage and the possibility of increased 90-day mortality that is not seen for more timely treatment. Furthermore, the frequently impaired nature of patients suffering an acute stroke and the difficulties in asking families to make life and death decisions in a highly time-sensitive context led the panel to restrict a strong endorsement of thrombolytic to the 3 hour outermost limit. The committee noted as well that Health Canada has not approved a thrombolytic agent beyond a three hour window in acute ischemic stroke.

Drosophila Fragile X Mental Retardation Protein Developmentally Regulates Activity-Dependent Axon Pruning

PubMed Central

Tessier, Charles R.; Broadie, Kendal

2014-01-01

Summary Fragile X Syndrome (FraX) is a broad-spectrum neurological disorder with symptoms ranging from hyperexcitability to mental retardation and autism. Loss of the fragile X mental retardation 1 (fmr1) gene product, the mRNA-binding translational regulator FMRP, causes structural over-elaboration of dendritic and axonal processes as well as functional alterations in synaptic plasticity at maturity. It is unclear, however, whether FraX is primarily a disease of development, a disease of plasticity or both; a distinction vital for engineering intervention strategies. To address this critical issue, we have used the Drosophila FraX model to investigate the developmental roles of Drosophila FMRP (dFMRP). dFMRP expression and regulation of chickadee/profilin coincides with a transient window of late brain development. During this time, dFMRP is positively regulated by sensory input activity, and required to limit axon growth and for efficient activity-dependent pruning of axon branches in the Mushroom Body learning/memory center. These results demonstrate that dFMRP has a primary role in activity-dependent neural circuit refinement in late brain development. PMID:18321984

Polycomb group (PcG) proteins and Pax6 cooperate to inhibit in vivo reprogramming of the developing Drosophila eye.

PubMed

Zhu, Jinjin; Ordway, Alison J; Weber, Lena; Buddika, Kasun; Kumar, Justin P

2018-04-04

How different cells and tissues commit to and determine their fates has been a central question in developmental biology since the seminal embryological experiments conducted by Wilhelm Roux and Hans Driesch in sea urchins and frogs. Here, we demonstrate that Polycomb group (PcG) proteins maintain Drosophila eye specification by suppressing the activation of alternative fate choices. The loss of PcG in the developing eye results in a cellular reprogramming event in which the eye is redirected to a wing fate. This fate transformation occurs with either the individual loss of Polycomb proteins or the simultaneous reduction of the Pleiohomeotic repressive complex and Pax6. Interestingly, the requirement for retinal selector genes is limited to Pax6, as the removal of more downstream members does not lead to the eye-wing transformation. We also show that distinct PcG complexes are required during different developmental windows throughout eye formation. These findings build on earlier observations that the eye can be reprogrammed to initiate head epidermis, antennal and leg development. © 2018. Published by The Company of Biologists Ltd.

Early structural and functional plasticity alterations in a susceptibility period of DYT1 dystonia mouse striatum.

PubMed

Maltese, Marta; Stanic, Jennifer; Tassone, Annalisa; Sciamanna, Giuseppe; Ponterio, Giulia; Vanni, Valentina; Martella, Giuseppina; Imbriani, Paola; Bonsi, Paola; Mercuri, Nicola Biagio; Gardoni, Fabrizio; Pisani, Antonio

2018-03-05

The onset of abnormal movements in DYT1 dystonia is between childhood and adolescence, although it is unclear why clinical manifestations appear during this developmental period. Plasticity at corticostriatal synapses is critically involved in motor memory. In the Tor1a +/Δgag DYT1 dystonia mouse model, long-term potentiation (LTP) appeared prematurely in a critical developmental window in striatal spiny neurons (SPNs), while long-term depression (LTD) was never recorded. Analysis of dendritic spines showed an increase of both spine width and mature mushroom spines in Tor1a +/Δgag neurons, paralleled by an enhanced AMPA receptor (AMPAR) accumulation. BDNF regulates AMPAR expression during development. Accordingly, both proBDNF and BDNF levels were significantly higher in Tor1a +/Δgag mice. Consistently, antagonism of BDNF rescued synaptic plasticity deficits and AMPA currents. Our findings demonstrate that early loss of functional and structural synaptic homeostasis represents a unique endophenotypic trait during striatal maturation, promoting the appearance of clinical manifestations in mutation carriers. © 2018, Maltese et al.

Audiovisual Simultaneity Judgment and Rapid Recalibration throughout the Lifespan.

PubMed

Noel, Jean-Paul; De Niear, Matthew; Van der Burg, Erik; Wallace, Mark T

2016-01-01

Multisensory interactions are well established to convey an array of perceptual and behavioral benefits. One of the key features of multisensory interactions is the temporal structure of the stimuli combined. In an effort to better characterize how temporal factors influence multisensory interactions across the lifespan, we examined audiovisual simultaneity judgment and the degree of rapid recalibration to paired audiovisual stimuli (Flash-Beep and Speech) in a sample of 220 participants ranging from 7 to 86 years of age. Results demonstrate a surprisingly protracted developmental time-course for both audiovisual simultaneity judgment and rapid recalibration, with neither reaching maturity until well into adolescence. Interestingly, correlational analyses revealed that audiovisual simultaneity judgments (i.e., the size of the audiovisual temporal window of simultaneity) and rapid recalibration significantly co-varied as a function of age. Together, our results represent the most complete description of age-related changes in audiovisual simultaneity judgments to date, as well as being the first to describe changes in the degree of rapid recalibration as a function of age. We propose that the developmental time-course of rapid recalibration scaffolds the maturation of more durable audiovisual temporal representations.

[Children with developmental coordination disorder have difficulty with action representation].

PubMed

Gabbard, Carl; Cacola, Priscila

The study of children with developmental coordination disorder (DCD) has emerged as a vibrant line of inquiry over the last two decades. The literature indicates quite clearly that children with DCD display deficits with an array of perceptual-motor and daily living skills. The movements of children with DCD are often described as clumsy and uncoordinated and lead to difficulties with performing many of the activities of daily living and sports that typically developing children perform easily. It has been hypothesized, based on limited research, that an underlying problem is a deficit in generating and/or monitoring an action representation termed the internal modeling deficit hypothesis. According to the hypothesis, children with DCD have significant limitations in their ability to accurately generate and utilize internal models of motor planning and control. The focus of this review is on one of the methods used to examine action representation-motor imagery, which theorists argue provides a window into the process of action representation. Included are research methods and possible brain structures involved. An addition, a paradigm unique with this population-estimation of reachability (distance) via motor imagery, will be described.

Developmental outcome after a single episode of status epilepticus.

PubMed

Roy, Hélène; Lippé, Sarah; Lussier, Francine; Sauerwein, Hannelore Catherine; Lortie, Anne; Lacroix, Jacques; Lassonde, Maryse

2011-08-01

Consequences of status epilepticus (SE) on psychomotor development and the specific impact of the convulsive event on emerging executive functions remain controversial. Infants treated for a single episode of SE, those treated for a single febrile seizure, and healthy infants were tested with respect to motor development, language, personal, and social skills and self-regulation. The children were divided into two age groups to investigate the impact of the convulsive event at different windows of brain maturation. We found that infants who had had SE were inferior to healthy controls on the development scales. Age differentiated SE impact on visuomotor development versus sociolinguistic development. Children who had been treated for SE had significantly more difficulties delaying a response to an attractive stimulus in one of the long-delay conditions. A single episode of SE can interfere with psychomotor and cognitive development in children without previous developmental delay, and it seems that the functions that are emerging at the time of insult are most vulnerable. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

Technology assessment: Some questions from a developing country perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goonatilake, S.

1994-01-01

The emergence of technology assessment did not occur in a societal or value vacuum; neither did its practice. Today`s TA expertise is the outcome of historically located concerns, still unique to a particular narrow space ({open_quotes}Euro America{close_quotes}) and a narrow time frame (post-1960s). There are wide cultural, economic, societal and historical variations in the developing world as compared to the developed Western nations. This variation limits the usefulness of the simple transfer of concepts developed in the West. There are also many different potential stakeholders in developing countries. These also include those outside the formal sectors who variously define desirablemore » and undesirable aspects of the social and other factors of technology. This results in different cultural definitions of ethics, different visions of gender equality, different attitudes to the environment, different contents and values in local knowledge systems, and different social organizations associated with a given technology. An effective TA should recognize this multiplicity. It requires cognition, action, and debate on these key factors. At times this becomes an unavoidable developmental debate. 45 refs.« less

The Zebrafish Models to Explore Genetic and Epigenetic Impacts on Evolutionary Developmental Origins of Aging

PubMed Central

Kishi, Shuji

2014-01-01

Can we reset, reprogram, rejuvenate or reverse the organismal aging process? Certain genetic manipulations could at least reset and reprogram epigenetic dynamics beyond phenotypic plasticity and elasticity in cells, which can be further manipulated into organisms. However, in a whole complex aging organism, how can we rejuvenate intrinsic resources and infrastructures in an intact/noninvasive manner? The incidence of diseases increases exponentially with age, accompanied by progressive deteriorations of physiological functions in organisms. Aging-associated diseases are sporadic but essentially inevitable complications arising from senescence. Senescence is often considered the antithesis of early development, but yet there may be factors and mechanisms in common between these two phenomena to rejuvenate over the dynamic process of aging. The association between early development and late-onset disease with advancing age is thought to come from a consequence of developmental plasticity, the phenomenon by which one genotype can give rise to a range of physiologically and/or morphologically adaptive states based on diverse epigenotypes, in response to intrinsic or extrinsic environmental cues and genetic perturbations. We hypothesized that the future aging process can be predictive based on adaptivity during the early developmental period. Modulating the thresholds and windows of plasticity and its robustness by molecular genetic and chemical epigenetic approaches, we have successfully conducted experiments to isolate zebrafish mutants expressing apparently altered senescence phenotypes during their embryonic and/or larval stages (“embryonic/larval senescence”). Subsequently, at least some of these mutant animals were found to show shortened lifespan, while some others would be expected to live longer in adulthoods. We anticipate that previously uncharacterized developmental genes may mediate the aging process and play a pivotal role in senescence. On the other hand, unexpected senescence-related genes might also be involved in the early developmental process and its regulation. The ease of manipulation using the zebrafish system allows us to conduct an exhaustive exploration of novel genes/genotypes and epigenotype that can be linked to the senescence phenotype, and thereby facilitates searching for the evolutionary and developmental origins of aging in vertebrates. PMID:24239812

Environmental Estrogens Differentially Engage the Histone Methyltransferase EZH2 to Increase Risk of Uterine Tumorigenesis

PubMed Central

Greathouse, K. Leigh; Bredfeldt, Tiffany; Everitt, Jeffrey I.; Lin, Kevin; Berry, Tia; Kannan, Kurunthachalam; Mittelstadt, Megan L.; Ho, Shuk-mei; Walker, Cheryl L.

2013-01-01

Environmental exposures during sensitive windows of development can reprogram normal physiological responses and alter disease susceptibility later in life in a process known as developmental reprogramming. For example, exposure to the xenoestrogen diethylstilbestrol (DES) during reproductive tract development can reprogram estrogen-responsive gene expression in the myometrium, resulting in hyper-responsiveness to hormone in the adult uterus and promotion of hormone-dependent uterine leiomyoma. We show here that the environmental estrogens genistein (GEN), a soy phytoestrogen, and the plasticizer bisphenol A (BPA), differ in their pattern of developmental reprogramming and promotion of tumorigenesis (leiomyomas) in the uterus. While both GEN and BPA induce genomic estrogen receptor (ER) signaling in the developing uterus, only GEN induced PI3K/AKT non-genomic ER signaling to the histone methyltransferase Enhancer of Zeste homolog 2 (EZH2). As a result, this “pre-genomic” signaling phosphorylates and represses EZH2, and reduces levels of H3K27 repressive mark in chromatin. Furthermore, only GEN caused estrogen-responsive genes in the adult myometrium to become hyper-responsive to hormone; estrogen-responsive genes were repressed in BPA exposed uteri. Importantly, this pattern of EZH2 engagement to decrease versus increase H3K27 methylation correlated with the effect of these xenoestrogens on tumorigenesis. Developmental reprogramming by GEN promoted development of uterine leiomyomas, increasing tumor incidence and multiplicity, while BPA did not. These data demonstrate that environmental estrogens have distinct non-genomic effects in the developing uterus that determines their ability to engage the epigenetic regulator EZH2, decrease levels of the repressive epigenetic histone H3K27 methyl mark in chromatin during developmental reprogramming, and promote uterine tumorigenesis. PMID:22504913

Early neural disruption and auditory processing outcomes in rodent models: implications for developmental language disability

PubMed Central

Fitch, R. Holly; Alexander, Michelle L.; Threlkeld, Steven W.

2013-01-01

Most researchers in the field of neural plasticity are familiar with the “Kennard Principle,” which purports a positive relationship between age at brain injury and severity of subsequent deficits (plateauing in adulthood). As an example, a child with left hemispherectomy can recover seemingly normal language, while an adult with focal injury to sub-regions of left temporal and/or frontal cortex can suffer dramatic and permanent language loss. Here we present data regarding the impact of early brain injury in rat models as a function of type and timing, measuring long-term behavioral outcomes via auditory discrimination tasks varying in temporal demand. These tasks were created to model (in rodents) aspects of human sensory processing that may correlate—both developmentally and functionally—with typical and atypical language. We found that bilateral focal lesions to the cortical plate in rats during active neuronal migration led to worse auditory outcomes than comparable lesions induced after cortical migration was complete. Conversely, unilateral hypoxic-ischemic (HI) injuries (similar to those seen in premature infants and term infants with birth complications) led to permanent auditory processing deficits when induced at a neurodevelopmental point comparable to human “term,” but only transient deficits (undetectable in adulthood) when induced in a “preterm” window. Convergent evidence suggests that regardless of when or how disruption of early neural development occurs, the consequences may be particularly deleterious to rapid auditory processing (RAP) outcomes when they trigger developmental alterations that extend into subcortical structures (i.e., lower sensory processing stations). Collective findings hold implications for the study of behavioral outcomes following early brain injury as well as genetic/environmental disruption, and are relevant to our understanding of the neurologic risk factors underlying developmental language disability in human populations. PMID:24155699

Optogenetic Examination of Prefrontal-Amygdala Synaptic Development.

PubMed

Arruda-Carvalho, Maithe; Wu, Wan-Chen; Cummings, Kirstie A; Clem, Roger L

2017-03-15

A brain network comprising the medial prefrontal cortex (mPFC) and amygdala plays important roles in developmentally regulated cognitive and emotional processes. However, very little is known about the maturation of mPFC-amygdala circuitry. We conducted anatomical tracing of mPFC projections and optogenetic interrogation of their synaptic connections with neurons in the basolateral amygdala (BLA) at neonatal to adult developmental stages in mice. Results indicate that mPFC-BLA projections exhibit delayed emergence relative to other mPFC pathways and establish synaptic transmission with BLA excitatory and inhibitory neurons in late infancy, events that coincide with a massive increase in overall synaptic drive. During subsequent adolescence, mPFC-BLA circuits are further modified by excitatory synaptic strengthening as well as a transient surge in feedforward inhibition. The latter was correlated with increased spontaneous inhibitory currents in excitatory neurons, suggesting that mPFC-BLA circuit maturation culminates in a period of exuberant GABAergic transmission. These findings establish a time course for the onset and refinement of mPFC-BLA transmission and point to potential sensitive periods in the development of this critical network. SIGNIFICANCE STATEMENT Human mPFC-amygdala functional connectivity is developmentally regulated and figures prominently in numerous psychiatric disorders with a high incidence of adolescent onset. However, it remains unclear when synaptic connections between these structures emerge or how their properties change with age. Our work establishes developmental windows and cellular substrates for synapse maturation in this pathway involving both excitatory and inhibitory circuits. The engagement of these substrates by early life experience may support the ontogeny of fundamental behaviors but could also lead to inappropriate circuit refinement and psychopathology in adverse situations. Copyright © 2017 the authors 0270-6474/17/372976-10$15.00/0.

The Development of Attentional Biases for Faces in Infancy: A Developmental Systems Perspective

PubMed Central

Reynolds, Greg D.; Roth, Kelly C.

2018-01-01

We present an integrative review of research and theory on major factors involved in the early development of attentional biases to faces. Research utilizing behavioral, eye-tracking, and neuroscience measures with infant participants as well as comparative research with animal subjects are reviewed. We begin with coverage of research demonstrating the presence of an attentional bias for faces shortly after birth, such as newborn infants’ visual preference for face-like over non-face stimuli. The role of experience and the process of perceptual narrowing in face processing are examined as infants begin to demonstrate enhanced behavioral and neural responsiveness to mother over stranger, female over male, own- over other-race, and native over non-native faces. Next, we cover research on developmental change in infants’ neural responsiveness to faces in multimodal contexts, such as audiovisual speech. We also explore the potential influence of arousal and attention on early perceptual preferences for faces. Lastly, the potential influence of the development of attention systems in the brain on social-cognitive processing is discussed. In conclusion, we interpret the findings under the framework of Developmental Systems Theory, emphasizing the combined and distributed influence of several factors, both internal (e.g., arousal, neural development) and external (e.g., early social experience) to the developing child, in the emergence of attentional biases that lead to enhanced responsiveness and processing of faces commonly encountered in the native environment. PMID:29541043

Narrowing the window of inflationary magnetogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Markkanen, Tommi; Nurmi, Sami; Räsänen, Syksy

2017-06-01

We consider inflationary magnetogenesis where the conformal symmetry is broken by the term f {sup 2}(φ) F {sub αβ} F {sup αβ}. We assume that the magnetic field power spectrum today between 0.1 and 10{sup 4} Mpc is a power law, with upper and lower limits from observation. This fixes f to be close to a power law in conformal time in the window during inflation when the modes observed today are generated. In contrast to previous work, we do not make any assumptions about the form of f outside these scales. We cover all possible reheating histories, described bymore » an average equation of state −1/3 < w-bar < 1. Requiring that strong coupling and large backreaction are avoided both at the background and perturbative level, we find the bound δ {sub B} {sub 0} < 5 ×10{sup −15} ( r /0.07){sup 1/2} κG for the magnetic field generated by inflation, where r is the tensor-to-scalar ratio and κ is a constant related to the form of f . This estimate has an uncertainty of one order of magnitude related to our approximations. The parameter κ is < 100, and values ∼> 1 require a highly fine-tuned form of f ; typical values are orders of magnitude smaller.« less

Microfluidic study of environmental control of genetic competence in Streptococcus mutans

NASA Astrophysics Data System (ADS)

Son, Minjun; Ghoreishilangroudi, Seyedehdelaram; Ahn, Sang-Joon; Burne, Robert; Hagen, Stephen

2015-03-01

The bacterial pathogen Streptococcus mutans has the ability to enter a transient state of genetic competence in which it can integrate exogenous DNA. It regulates the competent state in response to several environmental inputs that include two quorum sensing peptides (CSP and XIP) as well as pH and other variables. However the interplay of these variables in regulating the competent state is poorly understood. We are using microfluidics to isolate and control environmental inputs and examine how the competence regulatory circuit responds at the single cell level. Our studies reveal that the pH of the growth environment plays a critical role in determining how cells respond to the quorum sensing signals: The response to both peptides is sharply tuned to a narrow window of near-neutral pH. Within this optimal pH range, a population responds unimodally to a XIP stimulus, and bimodally to CSP; outside this range the response to both signals is suppressed. Because a growing S. mutans culture acidifies its medium, our findings suggest that the passage of the pH through the sensitivity window transiently activates the competence circuit. In this way a sharply tuned environmental response gives S. mutans fine control over the duration of its competent state. This work is supported by the NIH under NIDCR awards R01 DE023339.

Tunable phonon-induced transparency in bilayer graphene nanoribbons.

PubMed

Yan, Hugen; Low, Tony; Guinea, Francisco; Xia, Fengnian; Avouris, Phaedon

2014-08-13

In the phenomenon of plasmon-induced transparency, which is a classical analogue of electromagnetically induced transparency (EIT) in atomic gases, the coherent interference between two plasmon modes results in an optical transparency window in a broad absorption spectrum. With the requirement of contrasting lifetimes, typically one of the plasmon modes involved is a dark mode that has limited coupling to the electromagnetic radiation and possesses relatively longer lifetime. Plasmon-induced transparency not only leads to light transmission at otherwise opaque frequency regions but also results in the slowing of light group velocity and enhanced optical nonlinearity. In this article, we report an analogous behavior, denoted as phonon-induced transparency (PIT), in AB-stacked bilayer graphene nanoribbons. Here, light absorption due to the plasmon excitation is suppressed in a narrow window due to the coupling with the infrared active Γ-point optical phonon, whose function here is similar to that of the dark plasmon mode in the plasmon-induced transparency. We further show that PIT in bilayer graphene is actively tunable by electrostatic gating and estimate a maximum slow light factor of around 500 at the phonon frequency of 1580 cm(-1), based on the measured spectra. Our demonstration opens an avenue for the exploration of few-photon nonlinear optics and slow light in this novel two-dimensional material.

Initial dynamics of the Norrish Type I reaction in acetone: probing wave packet motion.

PubMed

Brogaard, Rasmus Y; Sølling, Theis I; Møller, Klaus B

2011-02-10

The Norrish Type I reaction in the S(1) (nπ*) state of acetone is a prototype case of ketone photochemistry. On the basis of results from time-resolved mass spectrometry (TRMS) and photoelectron spectroscopy (TRPES) experiments, it was recently suggested that after excitation the wave packet travels toward the S(1) minimum in less than 30 fs and stays there for more than 100 picoseconds [Chem. Phys. Lett.2008, 461, 193]. In this work we present simulated TRMS and TRPES signals based on ab initio multiple spawning simulations of the dynamics during the first 200 fs after excitation, getting quite good agreement with the experimental signals. We can explain the ultrafast decay of the experimental signals in the following manner: the wave packet simply travels, mainly along the deplanarization coordinate, out of the detection window of the ionizing probe. This window is so narrow that subsequent revival of the signal due to the coherent deplanarization vibration is not observed, meaning that from the point of view of the experiment the wave packets travels directly to the S(1) minimum. This result stresses the importance of pursuing a closer link to the experimental signal when using molecular dynamics simulations in interpreting experimental results.

Pre- versus post-exercise protein intake has similar effects on muscular adaptations.

PubMed

Schoenfeld, Brad Jon; Aragon, Alan; Wilborn, Colin; Urbina, Stacie L; Hayward, Sara E; Krieger, James

2017-01-01

The purpose of this study was to test the anabolic window theory by investigating muscle strength, hypertrophy, and body composition changes in response to an equal dose of protein consumed either immediately pre- versus post-resistance training (RT) in trained men. Subjects were 21 resistance-trained men (>1 year RT experience) recruited from a university population. After baseline testing, participants were randomly assigned to 1 of 2 experimental groups: a group that consumed a supplement containing 25 g protein and 1 g carbohydrate immediately prior to exercise (PRE-SUPP) ( n  = 9) or a group that consumed the same supplement immediately post-exercise (POST-SUPP) ( n  = 12). The RT protocol consisted of three weekly sessions performed on non-consecutive days for 10 weeks. A total-body routine was employed with three sets of 8-12 repetitions for each exercise. Results showed that pre- and post-workout protein consumption had similar effects on all measures studied ( p  > 0.05). These findings refute the contention of a narrow post-exercise anabolic window to maximize the muscular response and instead lends support to the theory that the interval for protein intake may be as wide as several hours or perhaps more after a training bout depending on when the pre-workout meal was consumed.

Magnetic properties and thermal stability of Ti-doped CrO2 films

NASA Astrophysics Data System (ADS)

Zhang, Z.; Cheng, M.; Lu, Z.; Yu, Z.; Liu, S.; Liang, R.; Liu, Y.; Shi, J.; Xiong, R.

2018-04-01

Chromium dioxide (CrO2) is a striking half metal material which may have important applications in the field of spintronics. However, pure CrO2 film is metastable at room temperature and the synthesis process can be only performed in a narrow temperature range of 390-410 °C with TiO2 used as substrate material. Here, we report the preparation and investigation of (1 0 0) oriented Ti-doped CrO2 films on TiO2 substrates. It is found that Ti-doped films can maintain pure rutile phase even after a 510 °C post-annealing, showing much better thermal stability than pure CrO2 films. Ti-doped films can be prepared in a wider temperature window (390-470 °C), which may be attributed to the improvement of thermal stability. The broadening of process window may be beneficial for further improvement of film quality by optimizing growth temperature in a larger range. In addition to the improvement of thermal stability, the magnetic properties of Ti-doped CrO2 are also found to be tuned by Ti doping: saturation magnetizations of Ti-doped films at room temperature are significantly lower, and magnetic anisotropy decreases as the Ti-concentration increases, which is beneficial for decreasing switching current density in STT-based spintronic devices.

Cationic flocculants carrying hydrophobic functionalities: applications for solid/liquid separation.

PubMed

Schwarz, S; Jaeger, W; Paulke, B-R; Bratskaya, S; Smolka, N; Bohrisch, J

2007-07-26

The flocculation behaviors of three series of polycations with narrow molecular weight distributions carrying hydrophobic substituents on their backbones [poly(N-vinylbenzyl-N,N,N-trimethylammonium chloride), poly(N-vinylbenzyl-N,N-dimethyl-N-butylammonium chloride), and poly(N-vinylbenzylpyridinium chloride)] were investigated in dispersions of monodisperse polystyrene latexes and kaolin. Apparently, the charge density of the polycations decreases with increasing substituent hydrophobicity and increasing molecular weight of the polyelectrolytes. The necessary amount of flocculant for phase separation in dispersions with high substrate surface charge densities increases with increasing hydrophobicity of the polyelectrolyte. Nevertheless, the introduction of hydrophobic functionalities is beneficial, resulting in a substantial broadening of the range between the minimum and maximum amounts of flocculant necessary for efficient flocculation (flocculation window). An increase in ionic strength supports this effect. When the substrate has a low charge density, the hydrophobic interactions play a much more significant role in the flocculation process. Here, the minimum efficient doses remained the same for all three polyelectrolytes investigated, but the width of the flocculation window increased as the polycation hydrophobicity and the molecular weight increased. The necessary amount of flocculant increased with an increase in particle size at constant solid content of the dispersion, as well as with a decreasing number of particles at a constant particle size.

Physical and chemical constraints limit the habitat window for an endangered mussel

USGS Publications Warehouse

Campbell, Cara; Prestegaard, Karen L.

2016-01-01

Development of effective conservation and restoration strategies for freshwater pearly mussels requires identification of environmental constraints on the distributions of individual mussel species. We examined whether the spatial distribution of the endangered Alasmidonta heterodon in Flat Brook, a tributary of the upper Delaware River, was constrained by water chemistry (i.e., calcium availability), bed mobility, or both. Alasmidonta heterodon populations were bracketed between upstream reaches that were under-saturated with respect to aragonite and downstream reaches that were saturated for aragonite during summer baseflow but had steep channels with high bed mobility. Variability in bed mobility and water chemistry along the length of Flat Brook create a “habitat window” for A. heterodon defined by bed stability (mobility index ≤1) and aragonite saturation (saturation index ≥1). We suggest the species may exist in a narrow biogeochemical window that is seasonally near saturation. Alasmidonta heterodon populations may be susceptible to climate change or anthropogenic disturbances that increase discharge, decrease groundwater inflow or chemistry, and thus affect either bed mobility or aragonite saturation. Identifying the biogeochemical microhabitats and requirements of individual mussel species and incorporating this knowledge into management decisions should enhance the conservation and restoration of endangered mussel species.

Stabilizing new bismuth compounds in thin film form [Stabilizing new thin film materials in bismuth compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Aiping; Zhou, Honghui; Zhu, Yuanyuan

2016-11-10

Growth of unexpected phases from a composite target of BiFeO 3:BiMnO 3 and/or BiFeO 3:BiCrO 3 has been explored using pulsed laser deposition. The Bi 2FeMnO 6 tetragonal phase can be grown directly on SrTiO 3 (STO) substrate, while two phases (S1 and S2) were found to grow on LaAlO 3 (LAO) substrates with narrow growth windows. However, introducing a thin CeO 2 buffer layer effectively broadens the growth window for the pure S1 phase, regardless of the substrate. Moreover, we discovered two new phases (X1 and X2) when growing on STO substrates using a BiFeO 3:BiCrO 3 target. Puremore » X2 phase can be obtained on CeO 2-buffered STO and LAO substrates. This work demonstrates that some unexpected phases can be stabilized in a thin film form by using composite perovskite BiRO 3 (R = Cr, Mn, Fe, Co, Ni) targets. Moreover, it also indicates that CeO 2 can serve as a general template for the growth of bismuth compounds with potential room-temperature multiferroicity.« less

Focusing-schlieren visualization in a dual-mode scramjet

NASA Astrophysics Data System (ADS)

Kouchi, Toshinori; Goyne, Christopher P.; Rockwell, Robert D.; McDaniel, James C.

2015-12-01

Schlieren imaging is particularly suited to measuring density gradients in compressible flowfields and can be used to capture shock waves and expansion fans, as well as the turbulent structures of mixing and wake flows. Conventional schlieren imaging, however, has difficulty clearly capturing such structures in long-duration supersonic combustion test facilities. This is because the severe flow temperatures locally change the refractive index of the window glass that is being used to provide optical access. On the other hand, focusing-schlieren imaging presents the potential of reduced sensitivity to thermal distortion of the windows and to clearly capture the flow structures even during a combustion test. This reduced sensitivity is due the technique's ability to achieve a narrow depth of focus. As part of this study, a focusing-schlieren system was developed with a depth of focus near ±5 mm and was applied to a direct-connect, continuous-flow type, supersonic combustion test facility with a stagnation temperature near 1200 K. The present system was used to successfully visualize the flowfield inside a dual-mode scramjet. The imaging system captured combustion-induced volumetric expansion of the fuel jet and an anchored bifurcated shock wave at the trailing edge of the ramp fuel injector. This is the first time successful focusing-schlieren measurements have been reported for a dual-mode scramjet.

Microscopic study on the carrier distribution in optoelectronic device structures: experiment and modeling

NASA Astrophysics Data System (ADS)

Huang, Wenchao; Xia, Hui; Wang, Shaowei; Deng, Honghai; Wei, Peng; Li, Lu; Liu, Fengqi; Li, Zhifeng; Li, Tianxin

2011-12-01

Scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) both are capable of mapping the 2-demensional carrier distribution in semiconductor device structures, which is essential in determining their electrical and optoelectronic performances. In this work, cross-sectional SCM1,2 is used to study the InGaAs/InP P-i-N junctions prepared by area-selective p-type diffusion. The diffusion lengths in the depth as well as the lateral directions are obtained for junctions under different window sizes in mask, which imply that narrow windows may result in shallow p-n junctions. The analysis is beneficial to design and fabricate focal plane array of near infrared photodetectors with high duty-cycle and quantum efficiency. On the other hand, SSRM provides unparalleled spatial resolution (<10 nm) in electrical characterization3 that is demanded for studying low-dimensional structures. However, to derive the carrier density from the measured local conductance in individual quantum structures, reliable model for SSRM is necessary but still not well established. Based on the carrier concentration related transport mechanisms, i.e. thermionic emission and thermionic field emission4,5, we developed a numerical model for the tip-sample Schottky contact4. The calculation is confronted with SSRM study on the dose-calibrated quantum wells (QWs).

Two Titans

NASA Image and Video Library

2017-08-11

These two views of Saturn's moon Titan exemplify how NASA's Cassini spacecraft has revealed the surface of this fascinating world. Cassini carried several instruments to pierce the veil of hydrocarbon haze that enshrouds Titan. The mission's imaging cameras also have several spectral filters sensitive to specific wavelengths of infrared light that are able to make it through the haze to the surface and back into space. These "spectral windows" have enable the imaging cameras to map nearly the entire surface of Titan. In addition to Titan's surface, images from both the imaging cameras and VIMS have provided windows into the moon's ever-changing atmosphere, chronicling the appearance and movement of hazes and clouds over the years. A large, bright and feathery band of summer clouds can be seen arcing across high northern latitudes in the view at right. These views were obtained with the Cassini spacecraft narrow-angle camera on March 21, 2017. Images taken using red, green and blue spectral filters were combined to create the natural-color view at left. The false-color view at right was made by substituting an infrared image (centered at 938 nanometers) for the red color channel. The views were acquired at a distance of approximately 613,000 miles (986,000 kilometers) from Titan. Image scale is about 4 miles (6 kilometers) per pixel. https://photojournal.jpl.nasa.gov/catalog/PIA21624

Human Milk Bacterial and Glycosylation Patterns Differ by Delivery Mode.

PubMed

Hoashi, Marina; Meche, Lawrence; Mahal, Lara K; Bakacs, Elizabeth; Nardella, Deanna; Naftolin, Frederick; Bar-Yam, Naomi; Dominguez-Bello, Maria G

2016-07-01

Mammals have evolved to nourish their offspring exclusively with maternal milk for around half of the lactation period, a crucial developmental window. In view of oral-breast contact during lactation and the differences in oral microbiota between cesarean section (C-section) and vaginally delivered infants, we expected differences in milk composition by delivery mode. We performed a cross-sectional study of banked human milk and found changes related to time since delivery in bacterial abundance and glycosylation patterns only in milk from women who delivered vaginally. The results warrant further research into the effects of delivery mode on milk microbes, milk glycosylation, and postpartum infant development. © The Author(s) 2015.

DNA methylation as a dynamic regulator of development and disease processes: spotlight on the prostate.

PubMed

Keil, Kimberly P; Vezina, Chad M

2015-01-01

Prostate development, benign hyperplasia and cancer involve androgen and growth factor signaling as well as stromal-epithelial interactions. We review how DNA methylation influences these and related processes in other organ systems such as how proliferation is restricted to specific cell populations during defined temporal windows, how androgens elicit their actions and how cells establish, maintain and remodel DNA methylation in a time and cell specific fashion. We also discuss mechanisms by which hormones and endocrine disrupting chemicals reprogram DNA methylation in the prostate and elsewhere and examine evidence for a reawakening of developmental epigenetic pathways as drivers of prostate cancer and benign prostate hyperplasia.

DNA methylation as a dynamic regulator of development and disease processes: spotlight on the prostate

PubMed Central

Keil, Kimberly P; Vezina, Chad M

2015-01-01

Prostate development, benign hyperplasia and cancer involve androgen and growth factor signaling as well as stromal–epithelial interactions. We review how DNA methylation influences these and related processes in other organ systems such as how proliferation is restricted to specific cell populations during defined temporal windows, how androgens elicit their actions and how cells establish, maintain and remodel DNA methylation in a time and cell specific fashion. We also discuss mechanisms by which hormones and endocrine disrupting chemicals reprogram DNA methylation in the prostate and elsewhere and examine evidence for a reawakening of developmental epigenetic pathways as drivers of prostate cancer and benign prostate hyperplasia. PMID:26077429

Tests of the Dynamic Field Theory and the Spatial Precision Hypothesis: Capturing a Qualitative Developmental Transition in Spatial Working Memory

PubMed Central

Schutte, Anne R.; Spencer, John P.

2009-01-01

This study tested a dynamic field theory (DFT) of spatial working memory and an associated spatial precision hypothesis (SPH). Between three and six years of age there is a qualitative shift in how children use reference axes to remember locations: 3-year-olds’ spatial recall responses are biased toward reference axes after short memory delays, whereas 6-year-olds’ responses are biased away from reference axes. According to the DFT and the SPH, quantitative improvements over development in the precision of excitatory and inhibitory working memory processes lead to this qualitative shift. Simulations of the DFT in Experiment 1 predict that improvements in precision should cause the spatial range of targets attracted toward a reference axis to narrow gradually over development with repulsion emerging and gradually increasing until responses to most targets show biases away from the axis. Results from Experiment 2 with 3- to 5-year-olds support these predictions. Simulations of the DFT in Experiment 3 quantitatively fit the empirical results and offer insights into the neural processes underlying this developmental change. PMID:19968430

Florence Goodenough and child study: The question of mothers as researchers.

PubMed

Johnson, Ann

2015-05-01

This article examines the views of early developmental psychologist Florence Goodenough, summarizing her contributions to the field, her complex viewpoints on science and gender issues, and her arguments for maternal record-keeping as a valuable scientific strategy, as drawn from her writings in textbooks, popular magazine articles, and private correspondence. During the 1920s, 1930s, and 1940s, when Goodenough enjoyed a high professional profile as a research scientist, the field of child psychology shifted from focus on producing applied knowledge to benefit parents and educators to a preference for laboratory-controlled basic science approaches to understanding development. Goodenough championed observation and other descriptive methods, including use of mothers as data collectors in the home, even while these approaches were increasingly discredited by prominent peers in the United States. I argue that Goodenough's allegiance to maternal record-keeping highlights a forgotten strand of context-sensitive, descriptive work that survived despite its general disparagement among proponents of a narrower version of strictly experimental developmental science emerging in the 1920s. (c) 2015 APA, all rights reserved).

Drug therapy management in patients with renal impairment: how to use creatinine-based formulas in clinical practice.

PubMed

Eppenga, Willemijn L; Kramers, Cornelis; Derijks, Hieronymus J; Wensing, Michel; Wetzels, Jack F M; De Smet, Peter A G M

2016-12-01

The use of estimated glomerular filtration rate (eGFR) in daily clinical practice. eGFR is a key component in drug therapy management (DTM) in patients with renal impairment. eGFR is routinely reported by laboratories whenever a serum creatinine testing is ordered. In this paper, we will discuss how to use eGFR knowing the limitations of serum creatinine-based formulas. Before starting a renally excreted drug, an equally effective drug which can be used more safely in patients with renal impairment should be considered. If a renally excreted drug is needed, the reliability of the eGFR should be assessed and when needed, a 24-h urine creatinine clearance collection should be performed. After achieving the best approximation of the true GFR, we suggest a gradual drug dose adaptation according to the renal function. A different approach for drugs with a narrow therapeutic window (NTW) is recommended compared to drugs with a broad therapeutic window. For practical purposes, a therapeutic window of 5 or less was defined as a NTW and a list of NTW drugs is presented. Considerations about the drug dose may be different at the start of the therapy or during the therapy and depending on the indication. Monitoring effectiveness and adverse drug reactions are important, especially for NTW drugs. Dose adjustment should be based on an ongoing assessment of clinical status and risk versus the benefit of the used regimen. When determining the most appropriate dosing regimen serum creatinine-based formulas should never be used naively but always in combination with clinical and pharmacological assessment of the individual patient.

The risk of acute liver injury associated with the use of antibiotics--evaluating robustness of results in the pharmacoepidemiological research on outcomes of therapeutics by a European consortium (PROTECT) project.

PubMed

Udo, Renate; Tcherny-Lessenot, Stéphanie; Brauer, Ruth; Dolin, Paul; Irvine, David; Wang, Yunxun; Auclert, Laurent; Juhaeri, Juhaeri; Kurz, Xavier; Abenhaim, Lucien; Grimaldi, Lamiae; De Bruin, Marie L

2016-03-01

To examine the robustness of findings of case-control studies on the association between acute liver injury (ALI) and antibiotic use in the following different situations: (i) Replication of a protocol in different databases, with different data types, as well as replication in the same database, but performed by a different research team. (ii) Varying algorithms to identify cases, with and without manual case validation. (iii) Different exposure windows for time at risk. Five case-control studies in four different databases were performed with a common study protocol as starting point to harmonize study outcome definitions, exposure definitions and statistical analyses. All five studies showed an increased risk of ALI associated with antibiotic use ranging from OR 2.6 (95% CI 1.3-5.4) to 7.7 (95% CI 2.0-29.3). Comparable trends could be observed in the five studies: (i) without manual validation the use of the narrowest definition for ALI showed higher risk estimates, (ii) narrow and broad algorithm definitions followed by manual validation of cases resulted in similar risk estimates, and (iii) the use of a larger window (30 days vs 14 days) to define time at risk led to a decrease in risk estimates. Reproduction of a study using a predefined protocol in different database settings is feasible, although assumptions had to be made and amendments in the protocol were inevitable. Despite differences, the strength of association was comparable between the studies. In addition, the impact of varying outcome definitions and time windows showed similar trends within the data sources. Copyright © 2015 John Wiley & Sons, Ltd.

Product screening of fast reactions in IR-laser-heated liquid water filaments in a vacuum by mass spectrometry.

PubMed

Charvat, A; Stasicki, B; Abel, B

2006-03-09

In the present article a novel approach for rapid product screening of fast reactions in IR-laser-heated liquid microbeams in a vacuum is highlighted. From absorbed energies, a shock wave analysis, high-speed laser stroboscopy, and thermodynamic data of high-temperature water the enthalpy, temperature, density, pressure, and the reaction time window for the hot water filament could be characterized. The experimental conditions (30 kbar, 1750 K, density approximately 1 g/cm3) present during the lifetime of the filament (20-30 ns) were extreme and provided a unique environment for high-temperature water chemistry. For the probe of the reaction products liquid beam desorption mass spectrometry was employed. A decisive feature of the technique is that ionic species, as well as neutral products and intermediates may be detected (neutrals as protonated aggregates) via time-of-flight mass spectrometry without any additional ionization laser. After the explosive disintegration of the superheated beam, high-temperature water reactions are efficiently quenched via expansion and evaporative cooling. For first exploratory experiments for chemistry in ultrahigh-temperature, -pressure and -density water, we have chosen resorcinol as a benchmark system, simple enough and well studied in high-temperature water environments much below 1000 K. Contrary to oxidation reactions usually present under less extreme and dense supercritical conditions, we have observed hydration and little H-atom abstraction during the narrow time window of the experiment. Small amounts of radicals but no ionic intermediates other than simple proton adducts were detected. The experimental findings are discussed in terms of the energetic and dense environment and the small time window for reaction, and they provide firm evidence for additional thermal reaction channels in extreme molecular environments.

The retina as a window to the brain-from eye research to CNS disorders.

PubMed

London, Anat; Benhar, Inbal; Schwartz, Michal

2013-01-01

Philosophers defined the eye as a window to the soul long before scientists addressed this cliché to determine its scientific basis and clinical relevance. Anatomically and developmentally, the retina is known as an extension of the CNS; it consists of retinal ganglion cells, the axons of which form the optic nerve, whose fibres are, in effect, CNS axons. The eye has unique physical structures and a local array of surface molecules and cytokines, and is host to specialized immune responses similar to those in the brain and spinal cord. Several well-defined neurodegenerative conditions that affect the brain and spinal cord have manifestations in the eye, and ocular symptoms often precede conventional diagnosis of such CNS disorders. Furthermore, various eye-specific pathologies share characteristics of other CNS pathologies. In this Review, we summarize data that support examination of the eye as a noninvasive approach to the diagnosis of select CNS diseases, and the use of the eye as a valuable model to study the CNS. Translation of eye research to CNS disease, and deciphering the role of immune cells in these two systems, could improve our understanding and, potentially, the treatment of neurodegenerative disorders.

Tuning the chemosensory window

PubMed Central

Zhou, Shanshan; Mackay, Trudy FC

2010-01-01

Accurate perception of chemical signals from the environment is critical for the fitness of most animals. Drosophila melanogaster experiences its chemical environment through families of chemoreceptors that include olfactory receptors, gustatory receptors and odorant binding proteins. Its chemical environment, however, changes during its life cycle and the interpretation of chemical signals is dependent on dynamic social and physical surroundings. Phenotypic plasticity of gene expression of the chemoreceptor repertoire allows flies to adjust the chemosensory window through which they “view” their world and to modify the ensemble of expressed chemoreceptor proteins in line with their developmental and physiological state and according to their needs to locate food and oviposition sites under different social and physical environmental conditions. Furthermore, males and females differ in their expression profiles of chemoreceptor genes. Thus, each sex experiences its chemical environment via combinatorial activation of distinct chemoreceptor ensembles. The remarkable phenotypic plasticity of the chemoreceptor repertoire raises several fundamental questions. What are the mechanisms that translate environmental cues into regulation of chemoreceptor gene expression? How are gustatory and olfactory cues integrated perceptually? What is the relationship between ensembles of odorant binding proteins and odorant receptors? And, what is the significance of co-regulated chemoreceptor transcriptional networks? PMID:20305396

Characterization and gene cloning of the rice (Oryza sativa L.) dwarf and narrow-leaf mutant dnl3.

PubMed

Shi, L; Wei, X J; Adedze, Y M N; Sheng, Z H; Tang, S Q; Hu, P S; Wang, J L

2016-09-16

The dwarf and narrow-leaf rice (Oryza sativa L.) mutant dnl3 was isolated from the Japonica cultivar Zhonghua 11 (wild-type). dnl3 exhibited pleiotropic developmental defects. The narrow-leaf phenotype resulted from a marked reduction in the number of vascular bundles, while the dwarf stature was caused by the formation of foreshortened internodes and a reduced number of parenchyma cells. The suggestion that cell division is impaired in the mutant was consistent with the transcriptional behavior of various genes associated with cell division. The mutant was less responsive to exogenously supplied gibberellic acid than the wild-type, and profiling the transcription of genes involved in gibberellin synthesis and response revealed that a lesion in the mutant affected gibberellin signal transduction. The dnl3 phenotype was inherited as a single-dominant gene, mapping within a 19.1-kb region of chromosome 12, which was found to harbor three open reading frames. Resequencing the open reading frames revealed that the mutant carried an allele at one of the three genes that differed from the wild-type sequence by 2-bp deletions; this gene encoded a cellulose synthase-like D4 (CSLD4) protein. Therefore, OsCSLD4 is a candidate gene for DNL3. DNL3 was expressed in all of the rice organs tested at the heading stage, particularly in the leaves, roots, and culms. These results suggest that DNL3 plays important roles in rice leaf morphogenesis and vegetative development.

Designing prospective cohort studies for assessing reproductive and developmental toxicity during sensitive windows of human reproduction and development--the LIFE Study.

PubMed

Buck Louis, Germaine M; Schisterman, Enrique F; Sweeney, Anne M; Wilcosky, Timothy C; Gore-Langton, Robert E; Lynch, Courtney D; Boyd Barr, Dana; Schrader, Steven M; Kim, Sungduk; Chen, Zhen; Sundaram, Rajeshwari

2011-09-01

The relationship between the environment and human fecundity and fertility remains virtually unstudied from a couple-based perspective in which longitudinal exposure data and biospecimens are captured across sensitive windows. In response, we completed the LIFE Study with methodology that intended to empirically evaluate a priori purported methodological challenges: implementation of population-based sampling frameworks suitable for recruiting couples planning pregnancy; obtaining environmental data across sensitive windows of reproduction and development; home-based biospecimen collection; and development of a data management system for hierarchical exposome data. We used two sampling frameworks (i.e., fish/wildlife licence registry and a direct marketing database) for 16 targeted counties with presumed environmental exposures to persistent organochlorine chemicals to recruit 501 couples planning pregnancies for prospective longitudinal follow-up while trying to conceive and throughout pregnancy. Enrolment rates varied from <1% of the targeted population (n = 424,423) to 42% of eligible couples who were successfully screened; 84% of the targeted population could not be reached, while 36% refused screening. Among enrolled couples, ∼ 85% completed daily journals while trying; 82% of pregnant women completed daily early pregnancy journals, and 80% completed monthly pregnancy journals. All couples provided baseline blood/urine samples; 94% of men provided one or more semen samples and 98% of women provided one or more saliva samples. Women successfully used urinary fertility monitors for identifying ovulation and home pregnancy test kits. Couples can be recruited for preconception cohorts and will comply with intensive data collection across sensitive windows. However, appropriately sized sampling frameworks are critical, given the small percentage of couples contacted found eligible and reportedly planning pregnancy at any point in time. © Published 2011. This article is a US Government work and is in the public domain in the USA.

Evolution of synchrotron-radiation-based Mössbauer absorption spectroscopy for various isotopes

NASA Astrophysics Data System (ADS)

Seto, Makoto; Masuda, Ryo; Kobayashi, Yasuhiro; Kitao, Shinji; Kurokuzu, Masayuki; Saito, Makina; Hosokawa, Shuuich; Ishibashi, Hiroki; Mitsui, Takaya; Yoda, Yoshitaka; Mibu, Ko

2017-11-01

Synchrotron-radiation-based Mössbauer spectroscopy that yields absorption type Mössbauer spectra has been applied to various isotopes. This method enables the advanced measurement by using the excellent features of synchrotron radiation, such as Mössbauer spectroscopic measurement under high-pressures. Furthermore, energy selectivity of synchrotron radiation allows us to measure 40K Mössbauer spectra, of which observation is impossible by using ordinary radioactive sources because the first excited state of 40K is not populated by any radioactive parent nuclides. Moreover, this method has flexibility of the experimental setup that the measured sample can be used as a transmitter or a scatterer, depending on the sample conditions. To enhance the measurement efficiency of the spectroscopy, we developed a detection system in which a windowless avalanche photodiode (APD) detector is combined with a vacuum cryostat to detect internal conversion electrons adding to X-rays accompanied by nuclear de-excitation. In particular, by selecting the emission from the scatterer sample, depth selective synchrotron-radiation-based Mössbauer spectroscopy is possible. Furthermore, limitation of the time window in the delayed components enables us to obtain narrow linewidth in Mössbauer spectra. Measurement system that records velocity dependent time spectra and energy information simultaneously realizes the depth selective and narrow linewidth measurement.

Determination of the vinyl fluoride line intensities by TDL spectroscopy: the object oriented approach of Visual Line Shape Fitting Program to line profile analysis

NASA Astrophysics Data System (ADS)

Tasinato, Nicola; Pietropolli Charmet, Andrea; Stoppa, Paolo; Giorgianni, Santi

2010-03-01

In this work the self-broadening coefficients and the integrated line intensities for a number of ro-vibrational transitions of vinyl fluoride have been determined for the first time by means of TDL spectroscopy. The spectra recorded in the atmospheric window around 8.7 µm appear very crowded with a density of about 90 lines per cm-1. In order to fit these spectral features a new fitting software has been implemented. The program, which is designed for laser spectroscopy, can fit many lines simultaneously on the basis of different theoretical profiles (Doppler, Lorentz, Voigt, Galatry and Nelkin-Ghatak). Details of the object oriented implementation of the application are given. The reliability of the program is demonstrated by determining the line parameters of some ro-vibrational lines of sulphur dioxide in the ν1 band region around 9 µm. Then the software is used for the line profile analysis of vinyl fluoride. The experimental line shapes show deviations from the Voigt profile, which can be well modelled by using a Dicke narrowed line shape function. This leads to the determination of the self-narrowing coefficient within the framework of the strong collision model.

Hydrodynamic chromatography of macromolecules using polymer monolithic columns.

PubMed

Edam, Rob; Eeltink, Sebastiaan; Vanhoutte, Dominique J D; Kok, Wim Th; Schoenmakers, Peter J

2011-12-02

The selectivity window of size-based separations of macromolecules was tailored by tuning the macropore size of polymer monolithic columns. Monolithic materials with pore sizes ranging between 75 nm and 1.2 μm were prepared in situ in large I.D. columns. The dominant separation mechanism was hydrodynamic chromatography in the flow-through pores. The calibration curves for synthetic polymers matched with the elution behavior by HDC separations in packed columns with 'analyte-to-pore' aspect ratios (λ) up to 0.2. For large-macropore monoliths, a deviation in retention behavior was observed for small polystyrene polymers (M(r)<20 kDa), which may be explained by a combined HDC-SEC mechanism for λ<0.02. The availability of monoliths with very narrow pore sizes allowed investigation of separations at high λ values. For high-molecular weight polymers (M(r)>300,000 Da) confined in narrow channels, the separation strongly depended on flow rate. Flow-rate dependent elution behavior was evaluated by calculation of Deborah numbers and confirmed to be outside the scope of classic shear deformation or slalom chromatography. Shear-induced forces acting on the periphery of coiled polymers in solution may be responsible for flow-rate dependent elution. Copyright © 2011 Elsevier B.V. All rights reserved.

Drug concentration heterogeneity facilitates the evolution of drug resistance.

PubMed

Kepler, T B; Perelson, A S

1998-09-29

Pathogenic microorganisms use Darwinian processes to circumvent attempts at their control through chemotherapy. In the case of HIV-1 infection, in which drug resistance is a continuing problem, we show that in one-compartment systems, there is a relatively narrow window of drug concentrations that allows evolution of resistant variants. When the system is enlarged to two spatially distinct compartments held at different drug concentrations with transport of virus between them, the range of average drug concentrations that allow evolution of resistance is significantly increased. For high average drug concentrations, resistance is very unlikely to arise without spatial heterogeneity. We argue that a quantitative understanding of the role played by heterogeneity in drug levels and pathogen transport is crucial for attempts to control re-emergent infectious disease.

The nature of earthquake prediction

USGS Publications Warehouse

Lindh, A.G.

1991-01-01

Earthquake prediction is inherently statistical. Although some people continue to think of earthquake prediction as the specification of the time, place, and magnitude of a future earthquake, it has been clear for at least a decade that this is an unrealistic and unreasonable definition. the reality is that earthquake prediction starts from the long-term forecasts of place and magnitude, with very approximate time constraints, and progresses, at least in principle, to a gradual narrowing of the time window as data and understanding permit. Primitive long-term forecasts are clearly possible at this time on a few well-characterized fault systems. Tightly focuses monitoring experiments aimed at short-term prediction are already underway in Parkfield, California, and in the Tokai region in Japan; only time will tell how much progress will be possible. 

Non-pharmaceutical therapies for stroke: Mechanisms and clinical implications

PubMed Central

Chen, Fan; Qi, Zhifeng; Luo, Yuming; Hinchliffe, Taylor; Ding, Guanghong; Xia, Ying; Ji, Xunming

2014-01-01

Stroke is deemed a worldwide leading cause of neurological disability and death, however, there is currently no promising pharmacotherapy for acute ischemic stroke aside from intravenous or intra-arterial thrombolysis. Yet because of the narrow therapeutic time window involved, thrombolytic application is very restricted in clinical settings. Accumulating data suggest that non-pharmaceutical therapies for stroke might provide new opportunities for stroke treatment. Here we review recent research progress in the mechanisms and clinical implications of non-pharmaceutical therapies, mainly including neuroprotective approaches such as hypothermia, ischemic/hypoxic conditioning, acupuncture, medical gases, transcranial laser therapy, etc. In addition, we briefly summarize mechanical endovascular recanalization devices and recovery devices for the treatment of the chronic phase of stroke and discuss the relative merits of these devices. PMID:24407111

Stimulated Raman Spectroscopy with Entangled Light: Enhanced Resolution and Pathway Selection

PubMed Central

2015-01-01

We propose a novel femtosecond stimulated Raman spectroscopy (FSRS) technique that combines entangled photons with interference detection to select matter pathways and enhance the resolution. Following photoexcitation by an actinic pump, the measurement uses a pair of broad-band entangled photons; one (signal) interacts with the molecule and together with a third narrow-band pulse induces the Raman process. The other (idler) photon provides a reference for the coincidence measurement. This interferometric photon coincidence counting detection allows one to separately measure the Raman gain and loss signals, which is not possible with conventional probe transmission detection. Entangled photons further provide a unique temporal and spectral detection window that can better resolve fast excited-state dynamics compared to classical and correlated disentangled states of light. PMID:25177427

A 100 mW-level single-mode switchable dual-wavelength erbium-doped fiber laser

NASA Astrophysics Data System (ADS)

Cheng, Jianqun; Zhang, Liaolin; Sharafudeen, Kaniyarakkal; Qiu, Jianrong

2013-10-01

A switchable dual-wavelength CW erbium-doped fiber laser with two cascaded fiber Bragg gratings has been proposed and demonstrated experimentally at room temperature. The laser uses a linear resonant cavity configuration incorporating a Sagnac loop with a polarization controller (PC) and can switch flexibly to output a single wavelength or dual wavelengths based on the polarization hole burning (PHB) effect. The slope efficiency and maximum output power can reach 23% and 96 mW, respectively. The two lasing peaks of the laser, with a narrow linewidth output and an optical signal-to-noise ratio of more than 50 dB, are located in the C and L bands of the optical communication window, respectively. The laser shows good stability with respect to the wavelength and output power.

The effect of working memory capacity limitations on the intuitive assessment of correlation: amplification, attenuation, or both?

PubMed

Cahan, Sorel; Mor, Yaniv

2007-03-01

This article challenges Yaakov Kareev's (1995a, 2000) argument regarding the positive bias of intuitive correlation estimates due to working memory capacity limitations and its adaptive value. The authors show that, under narrow window theory's primacy effect assumption, there is a considerable between-individual variability of the effects of capacity limitations on the intuitive assessment of correlation, in terms of both sign and magnitude: Limited capacity acts as an amplifier for some individuals and as a silencer for others. Furthermore, the average amount of attenuation exceeds the average amount of amplification, and the more so, the smaller the capacity. Implications regarding the applicability and contribution of the bias notion in this context and the evaluation of the adaptive value of capacity limitations are discussed.

Crocodilian Nest in a Late Cretaceous Sauropod Hatchery from the Type Lameta Ghat Locality, Jabalpur, India

PubMed Central

Srivastava, Rahul; Patnaik, Rajeev; Shukla, U. K.; Sahni, Ashok

2015-01-01

The well-known Late Cretaceous Lameta Ghat locality (Jabalpur, India) provides a window of opportunity to study a large stable, near shore sandy beach, which was widely used by sauropod dinosaurs as a hatchery. In this paper, we revisit the eggs and eggshell fragments previously assigned to lizards from this locality and reassign them to crocodylomorphs. Several features point to a crocodilian affinity, including a subspherical to ellipsoidal shape, smooth, uneven external surface, discrete trapezoid shaped shell units with wide top and narrow base, basal knobs and wedge shaped crystallites showing typical inverted triangular extinction under crossed nicols. The crocodylomorph eggshell material presented in this paper adds to the skeletal data of these most probably Cretaceous-Eocene dryosaurid crocodiles. PMID:26641665

Apparatus For Linewidth Reduction in Distributed Feedback or Distributed Bragg Reflector Semiconductor Lasers Using Vertical Emission

NASA Technical Reports Server (NTRS)

Cook, Anthony L. (Inventor); Hendricks, Herbert D. (Inventor)

2000-01-01

The linewidth of a distributed feedback semiconductor laser or a distributed Bragg reflector laser having one or more second order gratings is reduced by using an external cavity to couple the vertical emission back into the laser. This method and device prevent disturbance of the main laser beam, provide unobstructed access to laser emission for the formation of the external cavity, and do not require a very narrow heat sink. Any distributed Bragg reflector semiconductor laser or distributed feedback semiconductor laser that can produce a vertical emission through the epitaxial material and through a window in the top metallization can be used. The external cavity can be formed with an optical fiber or with a lens and a mirror or grating.

Method and Apparatus for Linewidth Reduction in Distributed Feedback or Distributed Bragg Reflector Semiconductor Lasers using Vertical Emission

NASA Technical Reports Server (NTRS)

Cook, Anthony L. (Inventor); Hendricks, Herbert D. (Inventor)

1998-01-01

The linewidth of a distributed feedback semiconductor laser or a distributed Bragg reflector laser having one or more second order gratings is reduced by using an external cavity to couple the vertical emission back into the laser. This method and device prevent disturbance of the main laser beam. provide unobstructed access to laser emission for the formation of the external cavity. and do not require a very narrow heat sink. Any distributed Bragg reflector semiconductor laser or distributed feedback semiconductor laser that can produce a vertical emission through the epitaxial material and through a window in the top metallization can be used. The external cavity can be formed with an optical fiber or with a lens and a mirror of grating.

Structure and enhanced thermochromic performance of low-temperature fabricated VO 2/V 2O 3 thin film

DOE PAGES

Sun, Guangyao; Cao, Xun; Gao, Xiang; ...

2016-10-06

For VO 2-based smart window manufacture, it is a long-standing demand for high-quality thin films deposited at low temperature. In this paper, the thermochromic films of VO 2 were deposited by a magnetron sputtering method at a fairly low temperature of 250 °C without subsequent annealing by embedding a V 2O 3 interlayer. V 2O 3 acts as a seed layer to lower the depositing temperature and buffer layer to epitaxial grow VO 2 film. The VO 2/V 2O 3 films display high solar modulating ability and narrow hysteresis loop. Finally, our data can serve as a promising point formore » industrial production with high degree of crystallinity at a low temperature.« less

Seismology and geodesy of the sun: low-frequency oscillations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dicke, R.H.

1981-04-01

The hourly averages of the solar ellipticity measured from June 13 to September 17, 1966, are analyzed for indications of solar oscillations with periods in excess of 2 h ..nu.. < 0.5 h/sup -1/. Nothing significant is found for frequencies ..nu.. > 0.1 hr/sup -1/ but for lower frequencies the power spectrum shows a very complex structure containing about 20 strong narrow peaks. The complexity is illusionary. The signal apparently consists of only two frequencies. The complexity is due to aliasing by the window function with its basic 24-h period, with many observational days missing, and with different numbers ofmore » hourly averages for the various observational days. Both signal frequencies are apparently due to odd-degree spherical harmonic oscillations of the sun.« less

Common Raven (Corvus corax) kleptoparasitism at a Golden Eagle (Aquila chyrsaetos) nest in southern Nevada

USGS Publications Warehouse

Simes, Matthew; Johnson, Diego R.; Streit, Justin; Longshore, Kathleen M.; Nussear, Kenneth E.; Esque, Todd C.

2017-01-01

The Common Raven (Corvus corax) is a ubiquitous species in the Mojave Desert of southern Nevada and California. From 5 to 24 May 2014, using remote trail cameras, we observed ravens repeatedly kleptoparasitizing food resources from the nest of a pair of Golden Eagles (Aquila chyrsaetos) in the Spring Mountains of southern Nevada. The ravens fed on nine (30%) of the 30 prey items delivered to the nest during the chick rearing period. Kleptoparasitic behavior by the ravens decreased as the eagle nestling matured to seven weeks of age, suggesting a narrow temporal window in which ravens can successfully engage in kleptoparasitic behavior at eagle nests. The observation of kleptoparasitism by Common Ravens at the nest suggests potential risks to young Golden Eagles from Common Ravens.

Visible-light absorption and large band-gap bowing of GaN 1-xSb x from first principles

DOE PAGES

Sheetz, R. Michael; Richter, Ernst; Andriotis, Antonis N.; ...

2011-08-01

Applicability of the Ga(Sb x)N 1-x alloys for practical realization of photoelectrochemical water splitting is investigated using first-principles density functional theory incorporating the local density approximation and generalized gradient approximation plus the Hubbard U parameter formalism. Our calculations reveal that a relatively small concentration of Sb impurities is sufficient to achieve a significant narrowing of the band gap, enabling absorption of visible light. Theoretical results predict that Ga(Sb x)N 1-x alloys with 2-eV band gaps straddle the potential window at moderate to low pH values, thus indicating that dilute Ga(Sb x)N 1-x alloys could be potential candidates for splitting watermore » under visible light irradiation.« less

PUF60 variants cause a syndrome of ID, short stature, microcephaly, coloboma, craniofacial, cardiac, renal and spinal features

PubMed Central

Low, Karen J; Ansari, Morad; Abou Jamra, Rami; Clarke, Angus; El Chehadeh, Salima; FitzPatrick, David R; Greenslade, Mark; Henderson, Alex; Hurst, Jane; Keller, Kory; Kuentz, Paul; Prescott, Trine; Roessler, Franziska; Selmer, Kaja K; Schneider, Michael C; Stewart, Fiona; Tatton-Brown, Katrina; Thevenon, Julien; Vigeland, Magnus D; Vogt, Julie; Willems, Marjolaine; Zonana, Jonathan; Study, D D D; Smithson, Sarah F

2017-01-01

PUF60 encodes a nucleic acid-binding protein, a component of multimeric complexes regulating RNA splicing and transcription. In 2013, patients with microdeletions of chromosome 8q24.3 including PUF60 were found to have developmental delay, microcephaly, craniofacial, renal and cardiac defects. Very similar phenotypes have been described in six patients with variants in PUF60, suggesting that it underlies the syndrome. We report 12 additional patients with PUF60 variants who were ascertained using exome sequencing: six through the Deciphering Developmental Disorders Study and six through similar projects. Detailed phenotypic analysis of all patients was undertaken. All 12 patients had de novo heterozygous PUF60 variants on exome analysis, each confirmed by Sanger sequencing: four frameshift variants resulting in premature stop codons, three missense variants that clustered within the RNA recognition motif of PUF60 and five essential splice-site (ESS) variant. Analysis of cDNA from a fibroblast cell line derived from one of the patients with an ESS variants revealed aberrant splicing. The consistent feature was developmental delay and most patients had short stature. The phenotypic variability was striking; however, we observed similarities including spinal segmentation anomalies, congenital heart disease, ocular colobomata, hand anomalies and (in two patients) unilateral renal agenesis/horseshoe kidney. Characteristic facial features included micrognathia, a thin upper lip and long philtrum, narrow almond-shaped palpebral fissures, synophrys, flared eyebrows and facial hypertrichosis. Heterozygote loss-of-function variants in PUF60 cause a phenotype comprising growth/developmental delay and craniofacial, cardiac, renal, ocular and spinal anomalies, adding to disorders of human development resulting from aberrant RNA processing/spliceosomal function. PMID:28327570

Embryonic exposure to sodium arsenite perturbs vascular development in zebrafish.

PubMed

McCollum, Catherine W; Hans, Charu; Shah, Shishir; Merchant, Fatima A; Gustafsson, Jan-Åke; Bondesson, Maria

2014-07-01

Exposure to arsenic in its inorganic form, arsenite, causes adverse effects to many different organs and tissues. Here, we have investigated arsenite-induced adverse effects on vascular tissues in the model organism zebrafish, Danio rerio. Zebrafish embryos were exposed to arsenite at different exposure windows and the susceptibility to vascular tissue damage was recorded at 72hours post fertilization (hpf). Intersegmental vessel sprouting and growth was most perturbed by exposure to arsenite during the 24-48hpf window, while disruption in the condensation of the caudal vein plexus was more often observed at the 48-72hpf exposure window, reflecting when these structures develop during normal embryogenesis. The vascular growth rate was decreased by arsenite exposure, and deviated from that of control embryos at around 24-26.5hpf. We further mapped changes in expression of key regulators of angiogenesis and vasculogenesis. Downregulation of vascular endothelial growth factor receptor 1/fms-related tyrosine kinase 1 (vegfr1/flt1) expression was evident already at 24hpf, coinciding with the decreased vascular growth rate. At later time points, matrix metalloproteinase 9 (mmp9) expression was upregulated, suggesting that arsenite affects the composition of the extracellular matrix. In total, the expression of eight key factors involved in different aspects of vascularization was significantly altered by arsenic exposure. In conclusion, our results show that arsenite is a potent vascular disruptor in the developing zebrafish embryo, a finding that calls for an evaluation of arsenite as a developmental vascular toxicant in mammalian model systems. Copyright © 2014 Elsevier B.V. All rights reserved.

Identifying a Window of Vulnerability during Fetal Development in a Maternal Iron Restriction Model

PubMed Central

Mihaila, Camelia; Schramm, Jordan; Strathmann, Frederick G.; Lee, Dawn L.; Gelein, Robert M.

2011-01-01

It is well acknowledged from observations in humans that iron deficiency during pregnancy can be associated with a number of developmental problems in the newborn and developing child. Due to the obvious limitations of human studies, the stage during gestation at which maternal iron deficiency causes an apparent impairment in the offspring remains elusive. In order to begin to understand the time window(s) during pregnancy that is/are especially susceptible to suboptimal iron levels, which may result in negative effects on the development of the fetus, we developed a rat model in which we were able to manipulate and monitor the dietary iron intake during specific stages of pregnancy and analyzed the developing fetuses. We established four different dietary-feeding protocols that were designed to render the fetuses iron deficient at different gestational stages. Based on a functional analysis that employed Auditory Brainstem Response measurements, we found that maternal iron restriction initiated prior to conception and during the first trimester were associated with profound changes in the developing fetus compared to iron restriction initiated later in pregnancy. We also showed that the presence of iron deficiency anemia, low body weight, and changes in core body temperature were not defining factors in the establishment of neural impairment in the rodent offspring. Our data may have significant relevance for understanding the impact of suboptimal iron levels during pregnancy not only on the mother but also on the developing fetus and hence might lead to a more informed timing of iron supplementation during pregnancy. PMID:21423661

Temporal Binding Window of the Sound-Induced Flash Illusion in Amblyopia.

PubMed

Narinesingh, Cindy; Goltz, Herbert C; Wong, Agnes M F

2017-03-01

Amblyopia is a neurodevelopmental visual disorder caused by abnormal visual experience in childhood. In addition to known visual deficits, there is evidence for changes in audiovisual integration in amblyopia using explicit tasks. We examined audiovisual integration in amblyopia using an implicit task that is more relevant in a real-world context. A total of 11 participants with amblyopia and 16 controls were tested binocularly and monocularly on the sound-induced flash illusion, in which flashes and beeps are presented concurrently and the perceived number of flashes is influenced by the number of beeps. The task used 1 to 2 rapid peripheral flashes presented with 0 to 2 beeps, at 5 stimulus onset asynchronies, that is, beep (-200 milliseconds, -100 milliseconds) or flash leading (100 milliseconds, 200 milliseconds) or simultaneous (0 milliseconds). Participants reported the number of perceived flashes. Susceptibility was indicated by a "2 flashes" response to "fission" (1 flash, 2 beeps) or "1 flash" to "fusion" (2 flashes, 1 beep). For fission with the beep leading during binocular viewing, controls showed an expected decrease in illusion strength as stimulus onset asynchronies increased, whereas the illusion strength remained constant in participants with amblyopia, indicating a wider temporal binding window in amblyopia (P = 0.007). For fusion, participants with amblyopia showed reduced illusion strength during amblyopic eye viewing (P = 0.044) with the flash leading. Amblyopia is associated with the widening of the temporal binding window, specifically for fission when viewing binocularly with the beep leading. This suggests a developmental adaptation to delayed amblyopic eye visual processing to optimize audiovisual integration.

Developmental neurotoxicity elicited by prenatal or postnatal chlorpyrifos exposure: effects on neurospecific proteins indicate changing vulnerabilities.

PubMed

Garcia, Stephanie J; Seidler, Frederic J; Slotkin, Theodore A

2003-03-01

The developmental neurotoxicity of the organophosphate pesticide chlorpyrifos (CPF) is thought to involve both neurons and glia, thus producing a prolonged window of vulnerability. To characterize the cell types and brain regions involved in these effects, we administered CPF to developing rats and examined neuroprotein markers for oligodendrocytes (myelin basic protein, MBP), for neuronal cell bodies (neurofilament 68 kDa, NF68), and for developing axons (neurofilament 200 kDa, NF200). Prenatal CPF administration on gestational days (GDs) 17-20 elicited an immediate (GD21) enhancement of MBP and NF68; by postnatal day (PN) 30, however, there were deficits in all three biomarkers, with the effect restricted to females. Exposure in the early postnatal period, PN1-4, did not evoke significant short-term or long-term changes in the neuroproteins. However, with treatment on PN11-14, we found reductions in MBP in the immediate posttreatment period (PN15, PN20) throughout the brain, and deficiencies across all three proteins emerged by PN30. With this regimen, males were targeted preferentially. The sex-selective effects seen here for the GD17-20 and PN11-14 regimens match those reported earlier for subsequent behavioral performance. These results indicate a shift in the populations of neural cells targeted by CPF, dependent upon the period of exposure. Similarly, developmental differences in the sex selectivity of the biochemical mechanisms underlying neurotoxicant actions are likely to contribute to discrete behavioral outcomes.

Life-Long Implications of Developmental Exposure to Environmental Stressors: New Perspectives.

PubMed

Grandjean, Philippe; Barouki, Robert; Bellinger, David C; Casteleyn, Ludwine; Chadwick, Lisa H; Cordier, Sylvaine; Etzel, Ruth A; Gray, Kimberly A; Ha, Eun-Hee; Junien, Claudine; Karagas, Margaret; Kawamoto, Toshihiro; Paige Lawrence, B; Perera, Frederica P; Prins, Gail S; Puga, Alvaro; Rosenfeld, Cheryl S; Sherr, David H; Sly, Peter D; Suk, William; Sun, Qi; Toppari, Jorma; van den Hazel, Peter; Walker, Cheryl L; Heindel, Jerrold J

2015-10-01

The Developmental Origins of Health and Disease (DOHaD) paradigm is one of the most rapidly expanding areas of biomedical research. Environmental stressors that can impact on DOHaD encompass a variety of environmental and occupational hazards as well as deficiency and oversupply of nutrients and energy. They can disrupt early developmental processes and lead to increased susceptibility to disease/dysfunctions later in life. Presentations at the fourth Conference on Prenatal Programming and Toxicity in Boston, in October 2014, provided important insights and led to new recommendations for research and public health action. The conference highlighted vulnerable exposure windows that can occur as early as the preconception period and epigenetics as a major mechanism than can lead to disadvantageous "reprogramming" of the genome, thereby potentially resulting in transgenerational effects. Stem cells can also be targets of environmental stressors, thus paving another way for effects that may last a lifetime. Current testing paradigms do not allow proper characterization of risk factors and their interactions. Thus, relevant exposure levels and combinations for testing must be identified from human exposure situations and outcome assessments. Testing of potential underpinning mechanisms and biomarker development require laboratory animal models and in vitro approaches. Only few large-scale birth cohorts exist, and collaboration between birth cohorts on a global scale should be facilitated. DOHaD-based research has a crucial role in establishing factors leading to detrimental outcomes and developing early preventative/remediation strategies to combat these risks.

Influence of conduct problems and depressive symptomatology on adolescent substance use: developmentally proximal versus distal effects.

PubMed

Maslowsky, Julie; Schulenberg, John E; Zucker, Robert A

2014-04-01

The identification of developmentally specific windows at which key predictors of adolescent substance use are most influential is a crucial task for informing the design of appropriately targeted substance use prevention and intervention programs. The current study examined effects of conduct problems and depressive symptomatology on changes in alcohol, cigarette, and marijuana from 8th through 12th grade. We examined the effects of relatively developmentally distal versus proximal mental health problems on adolescent substance use and tested for gender differences. With a national, longitudinal sample from the Monitoring the Future study (N = 3,014), structural equation modeling was used to test the effects of 8th and 10th grade conduct problems and depressive symptomatology on subsequent changes in alcohol, cigarette, and marijuana use from 8th through 12th grade. Results indicated that relatively distal (8th grade) mental health problems were stronger predictors of increases in alcohol, cigarette, and marijuana use than were relatively more proximal (10th grade) mental health problems. Eighth grade conduct problems had the strongest effects on alcohol and marijuana use, and 8th grade depressive symptomatology had the strongest effects on cigarette use. Few gender differences were observed. These results suggest that intervening in earlier appearing conduct problems and depressive symptomatology may lead to a reduction in adolescent substance use in 10th and 12th grades and beyond. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Redox dynamics of manganese as a mitochondrial life-death switch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Matthew Ryan; Fernandes, Jolyn; Go, Young-Mi

Sten Orrenius, M.D., Ph.D., pioneered many areas of cellular and molecular toxicology and made seminal contributions to our knowledge of oxidative stress and glutathione (GSH) metabolism, organellar functions and Ca{sup +2}-dependent mechanisms of cell death, and mechanisms of apoptosis. On the occasion of his 80{sup th} birthday, we summarize current knowledge on redox biology of manganese (Mn) and its role in mechanisms of cell death. Mn is found in all organisms and has critical roles in cell survival and death mechanisms by regulating Mn-containing enzymes such as manganese superoxide dismutase (SOD2) or affecting expression and activity of caspases. Occupational exposuresmore » to Mn cause “manganism”, a Parkinson's disease-like condition of neurotoxicity, and experimental studies show that Mn exposure leads to accumulation of Mn in the brain, especially in mitochondria, and neuronal cell death occurs with features of an apoptotic mechanism. Interesting questions are why a ubiquitous metal that is essential for mitochondrial function would accumulate to excessive levels, cause increased H{sub 2}O{sub 2} production and lead to cell death. Is this due to the interactions of Mn with other essential metals, such as iron, or with toxic metals, such as cadmium? Why is the Mn loading in the human brain so variable, and why is there such a narrow window between dietary adequacy and toxicity? Are non-neuronal tissues similarly vulnerable to insufficiency and excess, yet not characterized? We conclude that Mn is an important component of the redox interface between an organism and its environment and warrants detailed studies to understand the role of Mn as a mitochondrial life-death switch. - Highlights: • Either insufficient or excess manganese activates mitochondria-mediated cell death. • The optimal healthy Mn exposure window is very narrow. • Mitochondrial H{sub 2}O{sub 2} production depends on Mn across physiologic to toxicologic range. • Integrative omics needed to understand complex Mn interaction in cell fate. • Mn is central to redox interface between an organism and its environment.« less

Sensitive Detection of Radiation-Induced Medulloblastomas after Acute or Protracted Gamma-Ray Exposures in Ptch1 Heterozygous Mice Using a Radiation-Specific Molecular Signature.

PubMed

Tsuruoka, Chizuru; Blyth, Benjamin J; Morioka, Takamitsu; Kaminishi, Mutsumi; Shinagawa, Mayumi; Shimada, Yoshiya; Kakinuma, Shizuko

2016-10-01

Recently reported studies have led to a heightened awareness of the risks of cancer induced by diagnostic radiological imaging, and in particular, the risk of brain cancer after childhood CT scans. One feature of Ptch1 +/- mice is their sensitivity to radiation-induced medulloblastomas (an embryonic cerebellar tumor) during a narrow window of time centered on the days around birth. Little is known about the dynamics of how dose protraction interacts with such narrow windows of sensitivity in individual tissues. Using medulloblastomas from irradiated Ptch1 +/- mice with a hybrid C3H × C57BL/6 F1 genetic background, we previously showed that the alleles retained on chromosome 13 (which harbors the Ptch1 gene) reveal two major mechanisms of loss of the wild-type allele. The loss of parental alleles from the telomere extending up to or past the Ptch1 locus by recombination (spontaneous type) accounts for almost all medulloblastomas in nonirradiated mice, while tumors in irradiated mice often exhibited interstitial deletions, which start downstream of the wild-type Ptch1 and extend up varying lengths towards the centromere (radiation type). In this study, Ptch1 +/- mice were exposed to an acute dose of either 100 or 500 mGy gamma rays in utero or postnatally, or the same radiation doses protracted over a four-day period, and were monitored for medulloblastoma development. The results showed dose- and age-dependent radiation-induced type tumors. Furthermore, the size of the radiation-induced deletion differed with the dose rate. The results of this work suggest that tumor latency may be related to the size of the deletion. In this study, 500 mGy exposure produced radiation-induced type tumors at all ages and dose rates, while 100 mGy exposure did not significantly produce radiation-induced type tumors. The radiation signature allows for unique mechanistic insight into the action of radiation to induce DNA lesions with known causal relationship to a specific tumor type, particularly for doses and dose rates that are relevant to both diagnostic and accidental radiological exposures.

Examining P-Wave Arrivals of Low-Frequency Earthquakes for Evidence of Attenuation and its Effects on Moment-Duration Scaling

NASA Astrophysics Data System (ADS)

Gerzina, J.; Rubin, A. M.

2017-12-01

Bostock et. al. (2015) found that low-frequency earthquake (LFE) duration is nearly independent of moment, a result that is surprising enough to warrant investigating whether it might be an artifact of attenuation. Bostock et. al. (2017) found that bulk crustal attenuation could not be the culprit, but suggested that near-source attenuation might cause pronounced depletion of high frequency S-waves. Despite their lower signal-to noise ratio, looking at the P-waves might be enlightening because they aren't expected to attenuate as much as S-waves in the high Vp/Vs region near the tremor source. We have examined P-wave arrivals of LFEs that occurred during episodic tremor in the Cascadia subduction zone with the goal of refining the relationship between LFE magnitude and duration.Bostock et. al's duration measurements were made on stacked templates rather than individual arrivals. Because members of Bostock's LFE families vary in location, and therefore in P-S delay time, aligning the stacks primarily on the S arrival may artificially widen the P pulse. To circumvent this, we used cross-station cross correlations on Bostock's detections to identify and stack events with similar locations and therefore similar P-S delay times, until P arrivals became visible. We then stacked these stacks based on cross-correlating the optimal P component in a small window surrounding the P arrival. Although this procedure narrowed both the P and S pulse widths, it did not dramatically narrow P in relation to S, nor did we observe different P pulse widths for small and large events.We also compared the frequency spectra of small windows around the expected P and S arrivals for each amplitude bin. Although there is more high-frequency content in P-waves than S-waves, we have not yet been able to resolve a difference in P-wave corner frequency for different event sizes. Thus our preliminary results support the notion that LFEs are intrinsically low frequency.

Evaluation of third molar development in the estimation of chronological age.

PubMed

Soares, Caio Belém Rodrigues Barros; Figueiroa, José Natal; Dantas, Renata Moura Xavier; Kurita, Lúcio Mitsuo; Pontual, Andréa dos Anjos; Ramos-Perez, Flávia Maria de Moraes; Perez, Danyel Elias da Cruz; Pontual, Maria Luiza dos Anjos

2015-09-01

The purpose of this study was to evaluate the correlation between chronological age and the degree of third molar mineralization by Demirjian's developmental stages (Demirjian et al., 1973) using panoramic radiography. From a total of 11.396 digital panoramic radiographs of patients from three oral radiology private clinics from the northeast region of Brazil, obtained from January to June 2009, 2097 radiographic images from patients aged between 6 and 22 years were selected. The images were analyzed individually by two obsevers using a 21-inch computer screen and Windows Picture and Fax Viewer. Reliability was achieved by intra- and interobserver evaluation, using the Kappa test. Chronological age, calcification stage, gender and third molar were interrelated using a multiple linear regression model, considering age as a response variable. There was reliability with Demirjian et al.'s developmental stage assesment, displaying a significant relationship between mineralization stages and patients' age (P<0.05). There was no significant difference between the average age and the calcification stage taking gender and localization of the third molar into consideration. It is possible to estimate chronological age based on Demirjian's stage of a third molar, regardless of gender and location. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Defining anural malformations in the context of a developmental problem

USGS Publications Warehouse

Meteyer, C.U.; Cole, Rebecca A.; Converse, K.A.; Docherty, D.E.; Wolcott, M.; Helgen, J.C.; Levey, R.; Eaton-Poole, L.; Burkhart, J.G.

2000-01-01

This paper summarizes terminology and general concepts involved in animal development for the purpose of providing background for the study and understanding of frog malformations. The results of our radiographic investigation of rear limb malformations in Rana pipiens provide evidence that frog malformations are the product of early developmental errors. Although bacteria, parasites and viruses were identified in these metamorphosed frogs, the relevant window to look for the teratogenic effect of these agents is in the early tadpole stage during limb development. As a result, our microbiological findings must be regarded as inconclusive relative to determining their contribution to malformations because we conducted our examinations on metamorphosed frogs not tadpoles. Future studies need to look at teratogenic agents (chemical, microbial, physical or mechanical) that are present in the embryo, tadpole, and their environments at the stages of development that are relevant for the malformation type. The impact of these teratogenic agents then needs to be assessed in appropriate animal models using studies that are designed to mimic field conditions. The results of these laboratory tests should then be analyzed in such a way that will allow comparison with the findings in the wild-caught tadpoles and frogs.

Computer aided diagnosis and treatment planning for developmental dysplasia of the hip

NASA Astrophysics Data System (ADS)

Li, Bin; Lu, Hongbing; Cai, Wenli; Li, Xiang; Meng, Jie; Liang, Zhengrong

2005-04-01

The developmental dysplasia of the hip (DDH) is a congenital malformation affecting the proximal femurs and acetabulum that are subluxatable, dislocatable, and dislocated. Early diagnosis and treatment is important because failure to diagnose and improper treatment can result in significant morbidity. In this paper, we designed and implemented a computer aided system for the diagnosis and treatment planning of this disease. With the design, the patient received CT (computed tomography) or MRI (magnetic resonance imaging) scan first. A mixture-based PV partial-volume algorithm was applied to perform bone segmentation on CT image, followed by three-dimensional (3D) reconstruction and display of the segmented image, demonstrating the special relationship between the acetabulum and femurs for visual judgment. Several standard procedures, such as Salter procedure, Pemberton procedure and Femoral Shortening osteotomy, were simulated on the screen to rehearse a virtual treatment plan. Quantitative measurement of Acetabular Index (AI) and Femoral Neck Anteversion (FNA) were performed on the 3D image for evaluation of DDH and treatment plans. PC graphics-card GPU architecture was exploited to accelerate the 3D rendering and geometric manipulation. The prototype system was implemented on PC/Windows environment and is currently under clinical trial on patient datasets.

Decreasing-Rate Pruning Optimizes the Construction of Efficient and Robust Distributed Networks.

PubMed

Navlakha, Saket; Barth, Alison L; Bar-Joseph, Ziv

2015-07-01

Robust, efficient, and low-cost networks are advantageous in both biological and engineered systems. During neural network development in the brain, synapses are massively over-produced and then pruned-back over time. This strategy is not commonly used when designing engineered networks, since adding connections that will soon be removed is considered wasteful. Here, we show that for large distributed routing networks, network function is markedly enhanced by hyper-connectivity followed by aggressive pruning and that the global rate of pruning, a developmental parameter not previously studied by experimentalists, plays a critical role in optimizing network structure. We first used high-throughput image analysis techniques to quantify the rate of pruning in the mammalian neocortex across a broad developmental time window and found that the rate is decreasing over time. Based on these results, we analyzed a model of computational routing networks and show using both theoretical analysis and simulations that decreasing rates lead to more robust and efficient networks compared to other rates. We also present an application of this strategy to improve the distributed design of airline networks. Thus, inspiration from neural network formation suggests effective ways to design distributed networks across several domains.

Decreasing-Rate Pruning Optimizes the Construction of Efficient and Robust Distributed Networks

PubMed Central

Navlakha, Saket; Barth, Alison L.; Bar-Joseph, Ziv

2015-01-01

Robust, efficient, and low-cost networks are advantageous in both biological and engineered systems. During neural network development in the brain, synapses are massively over-produced and then pruned-back over time. This strategy is not commonly used when designing engineered networks, since adding connections that will soon be removed is considered wasteful. Here, we show that for large distributed routing networks, network function is markedly enhanced by hyper-connectivity followed by aggressive pruning and that the global rate of pruning, a developmental parameter not previously studied by experimentalists, plays a critical role in optimizing network structure. We first used high-throughput image analysis techniques to quantify the rate of pruning in the mammalian neocortex across a broad developmental time window and found that the rate is decreasing over time. Based on these results, we analyzed a model of computational routing networks and show using both theoretical analysis and simulations that decreasing rates lead to more robust and efficient networks compared to other rates. We also present an application of this strategy to improve the distributed design of airline networks. Thus, inspiration from neural network formation suggests effective ways to design distributed networks across several domains. PMID:26217933

Prolonged in vivo imaging of Xenopus laevis.

PubMed

Hamilton, Paul W; Henry, Jonathan J

2014-08-01

While live imaging of embryonic development over long periods of time is a well established method for embryos of the frog Xenopus laevis, once development has progressed to the swimming stages, continuous live imaging becomes more challenging because the tadpoles must be immobilized. Current imaging techniques for these advanced stages generally require bringing the tadpoles in and out of anesthesia for short imaging sessions at selected time points, severely limiting the resolution of the data. Here we demonstrate that creating a constant flow of diluted tricaine methanesulfonate (MS-222) over a tadpole greatly improves their survival under anesthesia. Based on this result, we describe a new method for imaging stage 48 to 65 X. laevis, by circulating the anesthetic using a peristaltic pump. This supports the animal during continuous live imaging sessions for at least 48 hr. The addition of a stable optical window allows for high quality imaging through the anesthetic solution. This automated imaging system provides for the first time a method for continuous observations of developmental and regenerative processes in advanced stages of Xenopus over 2 days. Developmental Dynamics 243:1011-1019, 2014. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

Maternal Diet Modulates Placenta Growth and Gene Expression in a Mouse Model of Diabetic Pregnancy

PubMed Central

Kappen, Claudia; Kruger, Claudia; MacGowan, Jacalyn; Salbaum, J. Michael

2012-01-01

Unfavorable maternal diet during pregnancy can predispose the offspring to diseases later in life, such as hypertension, metabolic syndrome, and obesity. However, the molecular basis for this phenomenon of “developmental programming” is poorly understood. We have recently shown that a diet nutritionally optimized for pregnancy can nevertheless be harmful in the context of diabetic pregnancy in the mouse, associated with a high incidence of neural tube defects and intrauterine growth restriction. We hypothesized that placental abnormalities may contribute to impaired fetal growth in these pregnancies, and therefore investigated the role of maternal diet in the placenta. LabDiet 5015 diet was associated with reduced placental growth, commencing at midgestation, when compared to pregnancies in which the diabetic dam was fed LabDiet 5001 maintenance chow. Furthermore, by quantitative RT-PCR we identify 34 genes whose expression in placenta at midgestation is modulated by diet, diabetes, or both, establishing biomarkers for gene-environment interactions in the placenta. These results implicate maternal diet as an important factor in pregnancy complications and suggest that the early phases of placenta development could be a critical time window for developmental origins of adult disease. PMID:22701643

Application of ERTS-1 data to the protection and management of New Jersey's coastal environment

NASA Technical Reports Server (NTRS)

Yunghans, R. S.; Feinberg, E. B.; Wobber, F. J.; Mairs, R. L. (Principal Investigator); Macomber, R. T.; Stanczuk, D.

1973-01-01

The author has identified the following significant results. A Coastal Zone Surveillance Program has been developed in which systematic comparisons of early ERTS-1 images and recently acquired images are regularly made to identify areas where changes have occurred. A methodology for assessing and documenting benefits has been established. Quantification of benefits has been directed toward four candidate areas: shore protection, ocean outfalls, coastal land resources, and offshore waste disposal. A refinement in the change detection analysis procedure has led to greater accuracy in spotting developmental changes in the Coastal Zone. Preliminary conclusions drawn from the Shore Erosion case study indicate that in the northern test area (developed beach) erosion has occurred more often, is generally more severe, and the beach is slower to recover than in the southern test area (natural beach). From these data it appears that it may be possible to define areas most likely to experience further erosion. The assumption of continued erosion in areas that have at one time experienced severe erosion is supported by the simple fact that as a beach narrows wave energy is concentrated on a narrower beach surface. The higher energy condition subsequently results in accelerated erosion.

Reproduction, embryonic development, and maternal transfer of contaminants in the amphibian Gastrophryne carolinensis.

PubMed

Hopkins, William Alexander; DuRant, Sarah Elizabeth; Staub, Brandon Patrick; Rowe, Christopher Lee; Jackson, Brian Phillip

2006-05-01

Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. Despite the severe effects of maternal transfer of contaminants on early development in other vertebrate lineages, no studies have examined the effects of maternal transfer of contaminants on reproduction or development in amphibians. We examined maternal transfer of contaminants in eastern narrow-mouth toads (Gastrophryne carolinensis) collected from a reference site and near a coal-burning power plant. Adult toads inhabiting the industrial area transferred significant quantities of selenium and strontium to their eggs, but Se concentrations were most notable (up to 100 microg/g dry mass). Compared with the reference site, hatching success was reduced by 11% in clutches from the contaminated site. In surviving larvae, the frequency of developmental abnormalities and abnormal swimming was 55-58% higher in the contaminated site relative to the reference site. Craniofacial abnormalities were nearly an order of magnitude more prevalent in hatchlings from the contaminated site. When all developmental criteria were considered collectively, offspring from the contaminated site experienced 19% lower viability. Although there was no statistical relationship between the concentration of Se or Sr transferred to eggs and any measure of offspring viability, our study demonstrates that maternal transfer may be an important route of contaminant exposure in amphibians that has been overlooked.

Reproduction, Embryonic Development, and Maternal Transfer of Contaminants in the Amphibian Gastrophryne carolinensis

PubMed Central

Hopkins, William Alexander; DuRant, Sarah Elizabeth; Staub, Brandon Patrick; Rowe, Christopher Lee; Jackson, Brian Phillip

2006-01-01

Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. Despite the severe effects of maternal transfer of contaminants on early development in other vertebrate lineages, no studies have examined the effects of maternal transfer of contaminants on reproduction or development in amphibians. We examined maternal transfer of contaminants in eastern narrow-mouth toads (Gastrophryne carolinensis) collected from a reference site and near a coal-burning power plant. Adult toads inhabiting the industrial area transferred significant quantities of selenium and strontium to their eggs, but Se concentrations were most notable (up to 100 μg/g dry mass). Compared with the reference site, hatching success was reduced by 11% in clutches from the contaminated site. In surviving larvae, the frequency of developmental abnormalities and abnormal swimming was 55–58% higher in the contaminated site relative to the reference site. Craniofacial abnormalities were nearly an order of magnitude more prevalent in hatchlings from the contaminated site. When all developmental criteria were considered collectively, offspring from the contaminated site experienced 19% lower viability. Although there was no statistical relationship between the concentration of Se or Sr transferred to eggs and any measure of offspring viability, our study demonstrates that maternal transfer may be an important route of contaminant exposure in amphibians that has been overlooked. PMID:16675417

Epigenetic medicine and fetal alcohol spectrum disorders

PubMed Central

Resendiz, Marisol; Chen, Yuanyuan; Öztürk, Nail C; Zhou, Feng C

2013-01-01

Epigenetic medicine is still in its infancy. To date, only a handful of diseases have documented epigenetic correlates upstream of gene regulation including cancer, developmental syndromes and late-onset diseases. The finding that epigenetic markers are dynamic and heterogeneous at tissue and cellular levels, combined with recent identification of a new form of functionally distinct DNA methylation has opened a wider window for investigators to pry into the epigenetic world. It is anticipated that many diseases will be elucidated through this epigenetic inquiry. In this review, we discuss the normal course of DNA methylation during development, taking alcohol as a demonstrator of the epigenetic impact of environmental factors in disease etiology, particularly the growth retardation and neurodevelopmental deficits of fetal alcohol spectrum disorders. PMID:23414322

Advances in asthma and allergy genetics in 2007.

PubMed

Vercelli, Donata

2008-08-01

This review discusses the main advances in the genetics of asthma and allergy published in the Journal in 2007. The association studies discussed herein addressed 3 main topics: the effect of the environment and gene-environment interactions on asthma/allergy susceptibility, the contribution of T(H)2 immunity gene variants to allergic inflammation, and the role of filaggrin mutations in atopic dermatitis and associated phenotypes. Other articles revealed novel, potentially important candidate genes or confirmed known ones. Collectively, the works published in 2007 reiterate that allergy and asthma are typical complex diseases; that is, they are disorders in which intricate interactions among environmental and genetic factors modify disease susceptibility by altering the fundamental structural and functional properties of target organs at critical developmental windows.

Applications of Space-Time Duality

NASA Astrophysics Data System (ADS)

Plansinis, Brent W.

The concept of space-time duality is based on a mathematical analogy between paraxial diffraction and narrowband dispersion, and has led to the development of temporal imaging systems. The first part of this thesis focuses on the development of a temporal imaging system for the Laboratory for Laser Energetics. Using an electro-optic phase modulator as a time lens, a time-to-frequency converter is constructed capable of imaging pulses between 3 and 12 ps. Numerical simulations show how this system can be improved to image the 1-30 ps range used in OMEGA-EP. By adjusting the timing between the pulse and the sinusoidal clock of the phase modulator, the pulse spectrum can be selectively narrowed, broadened, or shifted. An experimental demonstration of this effect achieved spectral narrowing and broadening by a factor of 2. Numerical simulations show narrowing by a factor of 8 is possible with modern phase modulators. The second part of this thesis explores the space-time analog of reflection and refraction from a moving refractive index boundary. From a physics perspective, a temporal boundary breaks translational symmetry in time, requiring the momentum of the photon to remain unchanged while its energy may change. This leads to a shifting and splitting of the pulse spectrum as the boundary is crossed. Equations for the reflected and transmitted frequencies and a condition for total internal reflection are found. Two of these boundaries form a temporal waveguide, which confines the pulse to a narrow temporal window. These waveguides have a finite number of modes, which do not change during propagation. A single-mode waveguide can be created, allowing only a single pulse shape to form within the waveguide. Temporal reflection and refraction produce a frequency dependent phase shift on the incident pulse, leading to interference fringes between the incident light and the reflected light. In a waveguide, this leads to self-imaging, where the pulse shape reforms periodically at finite propagation lengths. Numerical simulations are performed for the specific case where the moving boundary is produced through cross-phase modulation. In this case, the Kerr nonlinearity causes the boundary to change during propagation, leading to unique temporal and spectral behavior.

Upgrading and performance of the SAO laser ranging system in Matera

NASA Technical Reports Server (NTRS)

Maddox, J.; Pearlman, M.; Throp, J.; Wohn, J.

1983-01-01

The performance of the SAO lasers was improved considerably in terms of accuracy, range noise, data yield, and reliability. With the narrower laser pulse (2.5-3.0 nsec) and a new analog pulse processing system, the systematic range errors were reduced to 3-5 cm and range noise has been reduced to 5-15 cm on low satellites and 10-18 cm on Lageos. Pulse repetition rate was increased to 30 ppm and considerable improvement has been made in signal-to-noise ratio by using a 3 Angstrom interference filter and by reducing the range gate window down to 200-400 nsec. The first upgraded system was installed in Arequipa, Peru in the spring of 1982. The second upgraded system is now in operation in Matera, Italy. The third system is expected to be installed in Israel during 1984.

First Mass Measurement of a 'Domestic' Microlens

NASA Astrophysics Data System (ADS)

Dong, Subo; Carey, Sean; Gould, Andrew; Zhu, Wei

2017-11-01

We propose to combine Spitzer, Gaia, and ground-based measurements to determine the mass, distance, and transverse velocity of the 'domestic' microlensing event J0507+2447. This is only the second 'domestic' event (microlensed source distance less than about 1 kpc) ever discovered, but this number is already 10 times higher than the number that are expected. Hence, determining the nature of these lenses would resolve a major puzzle. The low expected rate is what caused Einstein to delay publication of his microlensing idea by 24 years. By very good fortune, Spitzer's narrow 38 day window of observations overlaps magnified portions of the event. To determine the mass requires to measure both the 'microlens parallax' (courtesy of Spitzer) and the 'angular Einstein radius' (which can be derived from Gaia astrometry). Thus, this is a truly rare opportunity to probe the nature of 'domestic' microlenses.

Two-particle correlation function and dihadron correlation approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vechernin, V. V., E-mail: v.vechernin@spbu.ru; Ivanov, K. O.; Neverov, D. I.

It is shown that, in the case of asymmetric nuclear interactions, the application of the traditional dihadron correlation approach to determining a two-particle correlation function C may lead to a form distorted in relation to the canonical pair correlation function {sub C}{sup 2}. This result was obtained both by means of exact analytic calculations of correlation functions within a simple string model for proton–nucleus and deuteron–nucleus collisions and by means of Monte Carlo simulations based on employing the HIJING event generator. It is also shown that the method based on studying multiplicity correlations in two narrow observation windows separated inmore » rapidity makes it possible to determine correctly the canonical pair correlation function C{sub 2} for all cases, including the case where the rapidity distribution of product particles is not uniform.« less

Anticoagulant management in the cardiovascular setting.

PubMed

Verheugt, Freek W A

2012-02-01

Vitamin K antagonists have been used as oral anticoagulants (OACs) for over five decades, yet their use in real-world practice is problematic primarily because of their narrow therapeutic window, exacerbated by extensive food and drug interactions, necessitating regular coagulation monitoring and dose adjustment. Around half of patients receiving warfarin are within the therapeutic range, exposing them to the dangers of under-anticoagulation (i.e. thrombosis formation) or over-anticoagulation (i.e. bleeding). A new generation of OACs with improved pharmacology promises to revolutionize antithrombotic management. Rivaroxaban, apixaban (both oral direct Factor Xa inhibitors) and dabigatran (a direct thrombin inhibitor) all exhibit predictable anticoagulant responses and few drug-drug interactions and do not require routine coagulation monitoring. © 2011 The Author Fundamental and Clinical Pharmacology © 2011 Société Française de Pharmacologie et de Thérapeutique.

A world unglued: simultanagnosia as a spatial restriction of attention

PubMed Central

Dalrymple, Kirsten A.; Barton, Jason J. S.; Kingstone, Alan

2013-01-01

Simultanagnosia is a disorder of visual attention that leaves a patient's world unglued: scenes and objects are perceived in a piecemeal manner. It is generally agreed that simultanagnosia is related to an impairment of attention, but it is unclear whether this impairment is object- or space-based in nature. We first consider the findings that support a concept of simultanagnosia as deficit of object-based attention. We then examine the evidence suggesting that simultanagnosia results from damage to a space-based attentional system, and in particular a model of simultanagnosia as a narrowed spatial window of attention. We ask whether seemingly object-based deficits can be explained by space-based mechanisms, and consider the evidence that object processing influences spatial deficits in this condition. Finally, we discuss limitations of a space-based attentional explanation. PMID:23616758

Beware the yellow slimming pill: fatal 2,4-dinitrophenol overdose.

PubMed

Holborow, Alexander; Purnell, Richard M; Wong, Jenny Frederina

2016-04-04

An industrial chemical, 2,4-dinitrophenol (DNP), has found use as a weight loss drug. It is extremely toxic in overdose and has a narrow therapeutic window with significant interindividual variability in metabolism. The rise in internet-based sales and distribution of this drug has seen an increased incidence of both accidental and intentional overdose presenting to emergency departments across the UK. No antidote currently exists and overdose is often fatal despite management based on current recommendations. We report a case of intentional overdose of DNP in a young man and discuss the current treatment guidelines. The case highlights the need for an increased awareness among frontline medical staff of the effects of DNP poisoning and questions the need for a more aggressive approach in the management of acute toxicity. 2016 BMJ Publishing Group Ltd.

Long-lived coherences: Improved dispersion in the frequency domain using continuous-wave and reduced-power windowed sustaining irradiation

NASA Astrophysics Data System (ADS)

Sadet, A.; Fernandes, L.; Kateb, F.; Balzan, R.; Vasos, P. R.

2014-08-01

Long-lived coherences (LLC's) are detectable magnetisation modes with favourable relaxation times that translate as sharp resonances upon Fourier transform. The frequency domain of LLC's was previously limited to the range of J-couplings within pairs of homonuclear spins. LLC evolution at high magnetic fields needs to be sustained by radio-frequency irradiation. We show that LLC-based spectral dispersion can be extended beyond the J-couplings domain using adapted carrier offsets and introduce a new reduced-power sustaining method to preserve LLC's within the required range of offsets. Spectral resolution is enhanced as the natively narrow lines of LLC's are further dispersed, making them potential probes for the study of biomolecules featuring strong resonance overlap and for media where NMR spectroscopy is commonly hindered by line broadening.

Protective Efficacy of Selenite against Lead-Induced Neurotoxicity in Caenorhabditis elegans

PubMed Central

Tseng, I-Ling; Liao, Vivian Hsiu-Chuan

2013-01-01

Background Selenium is an essential micronutrient that has a narrow exposure window between its beneficial and toxic effects. This study investigated the protective potential of selenite (IV) against lead (Pb(II))-induced neurotoxicity in Caenorhabditis elegans. Principal Findings The results showed that Se(IV) (0.01 µM) pretreatment ameliorated the decline of locomotion behaviors (frequencies of body bends, head thrashes, and reversal ) of C. elegans that are damaged by Pb(II) (100 µM) exposure. The intracellular ROS level of C. elegans induced by Pb(II) exposure was significantly lowered by Se(IV) supplementation prior to Pb(II) exposure. Finally, Se(IV) protects AFD sensory neurons from Pb(II)-induced toxicity. Conclusions Our study suggests that Se(IV) has protective activities against Pb(II)-induced neurotoxicity through its antioxidant property. PMID:23638060

Terahertz atmospheric attenuation and continuum effects

NASA Astrophysics Data System (ADS)

Slocum, David M.; Goyette, Thomas M.; Slingerland, Elizabeth J.; Giles, Robert H.; Nixon, William E.

2013-05-01

Remote sensing over long path lengths has become of greater interest in the terahertz frequency region. Applications such as pollution monitoring and detection of energetic chemicals are of particular interest. Although there has been much attention to atmospheric effects over narrow frequency windows, accurate measurements across a wide spectrum is lacking. The water vapor continuum absorption spectrum was investigated using Fourier Transform Spectroscopy. The continuum effect gives rise to an excess absorption that is unaccounted for in just a resonant line spectrum simulation. The transmission of broadband terahertz radiation from 0.300THz - 1.5THz through air with varying relative humidity levels was recorded for multiple path lengths. From these data, the absorption coefficient as a function of frequency was determined and compared with model calculations. The intensity and location of the strong absorption lines were in good agreement with spectral databases such as the 2008 HITRAN database and the JPL database. However, a noticeable continuum effect was observed particularly in the atmospheric transmission windows. A small discrepancy still remained even after accounting for continuum absorption using the best available data from the literature. This discrepancy, when projected over a one kilometer path length, typical of distances used in remote sensing, can cause a 30dB difference between calculated and observed attenuation. From the experimental and resonant line simulation spectra the air-broadening continuum parameter was calculated and compared with values available in the literature.

Design optimization of highly asymmetrical layouts by 2D contour metrology

NASA Astrophysics Data System (ADS)

Hu, C. M.; Lo, Fred; Yang, Elvis; Yang, T. H.; Chen, K. C.

2018-03-01

As design pitch shrinks to the resolution limit of up-to-date optical lithography technology, the Critical Dimension (CD) variation tolerance has been dramatically decreased for ensuring the functionality of device. One of critical challenges associates with the narrower CD tolerance for whole chip area is the proximity effect control on asymmetrical layout environments. To fulfill the tight CD control of complex features, the Critical Dimension Scanning Electron Microscope (CD-SEM) based measurement results for qualifying process window and establishing the Optical Proximity Correction (OPC) model become insufficient, thus 2D contour extraction technique [1-5] has been an increasingly important approach for complementing the insufficiencies of traditional CD measurement algorithm. To alleviate the long cycle time and high cost penalties for product verification, manufacturing requirements are better to be well handled at design stage to improve the quality and yield of ICs. In this work, in-house 2D contour extraction platform was established for layout design optimization of 39nm half-pitch Self-Aligned Double Patterning (SADP) process layer. Combining with the adoption of Process Variation Band Index (PVBI), the contour extraction platform enables layout optimization speedup as comparing to traditional methods. The capabilities of identifying and handling lithography hotspots in complex layout environments of 2D contour extraction platform allow process window aware layout optimization to meet the manufacturing requirements.

Precision glass molding: Toward an optimal fabrication of optical lenses

NASA Astrophysics Data System (ADS)

Zhang, Liangchi; Liu, Weidong

2017-03-01

It is costly and time consuming to use machining processes, such as grinding, polishing and lapping, to produce optical glass lenses with complex features. Precision glass molding (PGM) has thus been developed to realize an efficient manufacture of such optical components in a single step. However, PGM faces various technical challenges. For example, a PGM process must be carried out within the super-cooled region of optical glass above its glass transition temperature, in which the material has an unstable non-equilibrium structure. Within a narrow window of allowable temperature variation, the glass viscosity can change from 105 to 1012 Pas due to the kinetic fragility of the super-cooled liquid. This makes a PGM process sensitive to its molding temperature. In addition, because of the structural relaxation in this temperature window, the atomic structure that governs the material properties is strongly dependent on time and thermal history. Such complexity often leads to residual stresses and shape distortion in a lens molded, causing unexpected changes in density and refractive index. This review will discuss some of the central issues in PGM processes and provide a method based on a manufacturing chain consideration from mold material selection, property and deformation characterization of optical glass to process optimization. The realization of such optimization is a necessary step for the Industry 4.0 of PGM.

Detecting signatures of selection in nine distinct lines of broiler chickens.

PubMed

Stainton, John J; Haley, Chris S; Charlesworth, Brain; Kranis, Andreas; Watson, Kellie; Wiener, Pamela

2015-02-01

Modern commercial chickens have been bred for one of two specific purposes: meat production (broilers) or egg production (layers). This has led to large phenotypic changes, so that the genomic signatures of selection may be detectable using statistical techniques. Genetic differentiation between nine distinct broiler lines was calculated using Weir and Cockerham's pairwise FST estimator for 11 003 genome-wide markers to identify regions showing evidence of differential selection across lines. Differentiation measures were averaged into overlapping sliding windows for each line, and a permutation approach was used to determine the significance of each window. A total of 51 regions were found to show significant differentiation between the lines. Several lines were consistently found to share significant regions, suggesting that the pattern of line divergence is related to selection for broiler traits. The majority of the 51 regions contain QTL relating to broiler traits, but only five of them were found to be significantly enriched for broiler QTL, including a region on chromosome 27 containing 39 broiler QTL and 114 genes. Additionally, a number of these regions have been identified by other selection mapping studies. This study has identified a large number of potential selection signatures, and further tests with higher-density marker data may narrow these regions down to individual genes. © 2014 Stichting International Foundation for Animal Genetics.

Nonvolatile Ferroelectric Memory Circuit Using Black Phosphorus Nanosheet-Based Field-Effect Transistors with P(VDF-TrFE) Polymer.

PubMed

Lee, Young Tack; Kwon, Hyeokjae; Kim, Jin Sung; Kim, Hong-Hee; Lee, Yun Jae; Lim, Jung Ah; Song, Yong-Won; Yi, Yeonjin; Choi, Won-Kook; Hwang, Do Kyung; Im, Seongil

2015-10-27

Two-dimensional van der Waals (2D vdWs) materials are a class of new materials that can provide important resources for future electronics and materials sciences due to their unique physical properties. Among 2D vdWs materials, black phosphorus (BP) has exhibited significant potential for use in electronic and optoelectronic applications because of its allotropic properties, high mobility, and direct and narrow band gap. Here, we demonstrate a few-layered BP-based nonvolatile memory transistor with a poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) ferroelectric top gate insulator. Experiments showed that our BP-based ferroelectric transistors operate satisfactorily at room temperature in ambient air and exhibit a clear memory window. Unlike conventional ambipolar BP transistors, our ferroelectric transistors showed only p-type characteristics due to the carbon-fluorine (C-F) dipole effect of the P(VDF-TrFE) layer, as well as the highest linear mobility value of 1159 cm(2) V(-1) s(-1) with a 10(3) on/off current ratio. For more advanced memory applications beyond unit memory devices, we implemented two memory inverter circuits, a resistive-load inverter circuit and a complementary inverter circuit, combined with an n-type molybdenum disulfide (MoS2) nanosheet. Our memory inverter circuits displayed a clear memory window of 15 V and memory output voltage efficiency of 95%.

Activation of GABA-A receptors during postnatal brain development increases anxiety- and depression-related behaviors in a time- and dose-dependent manner in adult mice.

PubMed

Salari, Ali-Akbar; Bakhtiari, Amir; Homberg, Judith R

2015-08-01

Disturbances of the gamma-amino butyric acid-ergic (GABAergic) system during postnatal development can have long-lasting consequences for later life behavior, like the individual's response to stress. However, it is unclear which postnatal windows of sensitivity to GABA-ergic modulations are associated with what later-life behavioral outcomes. Therefore, we sought to determine whether neonatal activation of the GABA-A receptor during two postnatal periods, an early window (postnatal day 3-5) and a late window (postnatal day 14-16), can affect anxiety- and depression-related behaviors in male mice in later life. To this end, mice were treated with either saline or muscimol (50, 100, 200, 300 and 500μg/kg) during the early and late postnatal periods. An additional group of mice was treated with the GABA-A receptor antagonist bicuculline+muscimol. When grown to adulthood male mice were exposed to behavioral tests to measure anxiety- and depression-related behaviors. Baseline and stress-induced corticosterone (CORT) levels were also measured. The results indicate that early postnatal and to a lesser extent later postnatal exposure to the GABA-A receptor agonist muscimol increased anxiety-like behavior and stress-induced CORT levels in adults. Moreover, the early postnatal treatment with muscimol increased depression-like behavior with increasing baseline CORT levels. The anxiogenic and depression-like later-life consequences could be antagonized by bicuculline. Our findings suggest that GABA-A receptor signaling during early-life can influence anxiety- and depression-related behaviors in a time- and dose-dependent manner in later life. Our findings help to increase insight in the developmental mechanisms contributing to stress-related disorders. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

Organizational effects of the antiandrogen, Vinclozolin, on penis development in the mouse.

PubMed

Amato, Ciro M; Boyd, Morgan; Yang, Joshua; McCoy, Krista A

2018-04-14

Endocrine disrupting chemicals (EDCs) are pollutants found throughout the environment that disrupt normal endocrine processes. In mice, penis development is thought to be most susceptible to EDCs during a critical developmental window occurring on embryonic days (E) 15.5-17.5. However, androgen signaling begins on E13.5 when Androgen Receptor (AR) protein is found in the genitalia and testosterone is circulating. We hypothesize that disrupting androgen signaling prior to the established critical window sensitizes the penis to future androgen disruption. To test this hypothesis, CD1 dams were exposed to Vinclozolin or a corn oil solvent control on E13.5 and E14.5 and AR levels were measured with immunohistochemistry on E14.5. Early antiandrogen exposure reduced AR within nuclei and decreased intensity of AR expression within E14.5 genitalia. To evaluate the influence of antiandrogen exposure before the known critical window of penis development, two groups of pregnant dams (n = 3) were exposed to Vinclozolin starting at either E13.5 or E14.5 and continued exposure through E16.5. Histology and M.O.U.S.E. scoring were used to quantify penis abnormalities. To account for differences in total doses mice experienced due to differences in length of dosing time, we compared animals that received the same total doses. Exposure to antiandrogens on E13.5 exacerbated malformations when exposure was continued through sexually dimorphic development. Both exposure time and Vinclozolin dose are important for severity of Vinclozolin-induced penis abnormalities in mice. This work shows, antiandrogen exposure prior to sensitive periods can exacerbate the effects of later antiandrogen exposure on reproductive development.

Different Electrophysiological Responses to Informative Value of Feedback Between Children and Adults.

PubMed

Du, Bin; Cao, Bihua; He, Weiqi; Li, Fuhong

2018-01-01

The ability to learn from feedback is important for children's adaptive behavior and school learning. Feedback has two main components, informative value and valence. How to disentangle these two components and what is the developmental neural correlates of using the informative value of feedback is still an open question. In this study, 23 children (7-10 years old) and 19 adults (19-22 years old) were asked to perform a rule induction task, in which they were required to find a rule, based on the informative value of feedback. Behavioral results indicated that the likelihood of correct searching behavior under negative feedback was low for children. Event-related potentials showed that (1) the effect of valence was processed in a wide time window, particularly in the N2 component; (2) the encoding process of the informative value of negative feedback began later for children than for adults; (3) a clear P300 was observed for adults; for children, however, P300 was absent in the frontal region; and (4) children processed the informative value of feedback chiefly in the left sites during the P300 time window, whereas adults did not show this laterality. These results suggested that children were less sensitive to the informative value of negative feedback possibly because of the immature brain.

Changes in the Metabolome in Response to Low-Dose Exposure to Environmental Chemicals Used in Personal Care Products during Different Windows of Susceptibility.

PubMed

Houten, Sander M; Chen, Jia; Belpoggi, Fiorella; Manservisi, Fabiana; Sánchez-Guijo, Alberto; Wudy, Stefan A; Teitelbaum, Susan L

2016-01-01

The consequences of ubiquitous exposure to environmental chemicals remain poorly defined. Non-targeted metabolomic profiling is an emerging method to identify biomarkers of the physiological response to such exposures. We investigated the effect of three commonly used ingredients in personal care products, diethyl phthalate (DEP), methylparaben (MPB) and triclosan (TCS), on the blood metabolome of female Sprague-Dawley rats. Animals were treated with low levels of these chemicals comparable to human exposures during prepubertal and pubertal windows as well as chronically from birth to adulthood. Non-targeted metabolomic profiling revealed that most of the variation in the metabolites was associated with developmental stage. The low-dose exposure to DEP, MPB and TCS had a relatively small, but detectable impact on the metabolome. Multiple metabolites that were affected by chemical exposure belonged to the same biochemical pathways including phenol sulfonation and metabolism of pyruvate, lyso-plasmalogens, unsaturated fatty acids and serotonin. Changes in phenol sulfonation and pyruvate metabolism were most pronounced in rats exposed to DEP during the prepubertal period. Our metabolomics analysis demonstrates that human level exposure to personal care product ingredients has detectable effects on the rat metabolome. We highlight specific pathways such as sulfonation that warrant further study.

The AP-1 transcription factor component Fosl2 potentiates the rate of myocardial differentiation from the zebrafish second heart field.

PubMed

Jahangiri, Leila; Sharpe, Michka; Novikov, Natasha; González-Rosa, Juan Manuel; Borikova, Asya; Nevis, Kathleen; Paffett-Lugassy, Noelle; Zhao, Long; Adams, Meghan; Guner-Ataman, Burcu; Burns, Caroline E; Burns, C Geoffrey

2016-01-01

The vertebrate heart forms through successive phases of cardiomyocyte differentiation. Initially, cardiomyocytes derived from first heart field (FHF) progenitors assemble the linear heart tube. Thereafter, second heart field (SHF) progenitors differentiate into cardiomyocytes that are accreted to the poles of the heart tube over a well-defined developmental window. Although heart tube elongation deficiencies lead to life-threatening congenital heart defects, the variables controlling the initiation, rate and duration of myocardial accretion remain obscure. Here, we demonstrate that the AP-1 transcription factor, Fos-like antigen 2 (Fosl2), potentiates the rate of myocardial accretion from the zebrafish SHF. fosl2 mutants initiate accretion appropriately, but cardiomyocyte production is sluggish, resulting in a ventricular deficit coupled with an accumulation of SHF progenitors. Surprisingly, mutant embryos eventually correct the myocardial deficit by extending the accretion window. Overexpression of Fosl2 also compromises production of SHF-derived ventricular cardiomyocytes, a phenotype that is consistent with precocious depletion of the progenitor pool. Our data implicate Fosl2 in promoting the progenitor to cardiomyocyte transition and uncover the existence of regulatory mechanisms to ensure appropriate SHF-mediated cardiomyocyte contribution irrespective of embryonic stage. © 2016. Published by The Company of Biologists Ltd.

Changes in the Metabolome in Response to Low-Dose Exposure to Environmental Chemicals Used in Personal Care Products during Different Windows of Susceptibility

PubMed Central

Chen, Jia; Belpoggi, Fiorella; Manservisi, Fabiana; Sánchez-Guijo, Alberto; Wudy, Stefan A.; Teitelbaum, Susan L.

2016-01-01

The consequences of ubiquitous exposure to environmental chemicals remain poorly defined. Non-targeted metabolomic profiling is an emerging method to identify biomarkers of the physiological response to such exposures. We investigated the effect of three commonly used ingredients in personal care products, diethyl phthalate (DEP), methylparaben (MPB) and triclosan (TCS), on the blood metabolome of female Sprague-Dawley rats. Animals were treated with low levels of these chemicals comparable to human exposures during prepubertal and pubertal windows as well as chronically from birth to adulthood. Non-targeted metabolomic profiling revealed that most of the variation in the metabolites was associated with developmental stage. The low-dose exposure to DEP, MPB and TCS had a relatively small, but detectable impact on the metabolome. Multiple metabolites that were affected by chemical exposure belonged to the same biochemical pathways including phenol sulfonation and metabolism of pyruvate, lyso-plasmalogens, unsaturated fatty acids and serotonin. Changes in phenol sulfonation and pyruvate metabolism were most pronounced in rats exposed to DEP during the prepubertal period. Our metabolomics analysis demonstrates that human level exposure to personal care product ingredients has detectable effects on the rat metabolome. We highlight specific pathways such as sulfonation that warrant further study. PMID:27467775

Trematode infection causes malformations and population effects in a declining New Zealand fish.

PubMed

Kelly, David W; Thomas, Harriet; Thieltges, David W; Poulin, Robert; Tompkins, Daniel M

2010-03-01

1. Animal malformations engender wide public and scientific concern because of associated environmental health risks. This is highlighted by increased incidence of limb malformations in amphibians associated with trematode infections and disturbance. Malformations may signal new emerging disease threats, but whether the phenomenon is broadly applicable across taxa, or has population-scale impacts, is unknown. 2. Malformations are widely reported in fish and, until now, have been attributed mainly to contaminants. We tested whether the trematode Telogaster opisthorchis caused severe malformations, leading to population effects, in Galaxias anomalus, a threatened New Zealand freshwater fish. 3. Experimental infection of larval fish caused increasing spinal malformation and mortality with infection intensity that closely matched field patterns. Field malformation frequency peaked in January (65%), before declining sharply in February (25%) and remaining low thereafter. 4. The peak occurred during a 'critical window' of larval development, with the decline coincident with a population crash, indicating that malformation was causing mortality in the field. 5. The occurrence of such critical developmental windows may explain why this mechanism of population impact has been overlooked. With global environmental stressors predicted to enhance trematode infections, our results show that parasite-induced malformation, and its population-scale impacts, could be more widespread than previously considered.

Automated Measurement of P- and S-Wave Differential Times for Imaging Spatial Distributions of Vp/Vs Ratio, with Moving-Window Cross-Correlation Technique

NASA Astrophysics Data System (ADS)

Taira, T.; Kato, A.

2013-12-01

A high-resolution Vp/Vs ratio estimate is one of the key parameters to understand spatial variations of composition and physical state within the Earth. Lin and Shearer (2007, BSSA) recently developed a methodology to obtain local Vp/Vs ratios in individual similar earthquake clusters, based on P- and S-wave differential times. A waveform cross-correlation approach is typically employed to measure those differential times for pairs of seismograms from similar earthquakes clusters, at narrow time windows around the direct P and S waves. This approach effectively collects P- and S-wave differential times and however requires the robust P- and S-wave time windows that are extracted based on either manually or automatically picked P- and S-phases. We present another technique to estimate P- and S-wave differential times by exploiting temporal properties of delayed time as a function of elapsed time on the seismograms with a moving-window cross-correlation analysis (e.g., Snieder, 2002, Phys. Rev. E; Niu et al. 2003, Nature). Our approach is based on the principle that the delayed time for the direct S wave differs from that for the direct P wave. Two seismograms aligned by the direct P waves from a pair of similar earthquakes yield that delayed times become zero around the direct P wave. In contrast, delayed times obtained from time windows including the direct S wave have non-zero value. Our approach, in principle, is capable of measuring both P- and S-wave differential times from single-component seismograms. In an ideal case, the temporal evolution of delayed time becomes a step function with its discontinuity at the onset of the direct S wave. The offset in the resulting step function would be the S-wave differential time, relative to the P-wave differential time as the two waveforms are aligned by the direct P wave. We apply our moving-window cross-correlation technique to the two different data sets collected at: 1) the Wakayama district, Japan and 2) the Geysers geothermal field, California. The both target areas are characterized by earthquake swarms that provide a number of similar events clusters. We use the following automated procedure to systematically analyze the two data sets: 1) the identification of the direct P arrivals by using an Akaike Information Criterion based phase picking algorithm introduced by Zhang and Thurber (2003, BSSA), 2) the waveform alignment by the P-wave with a waveform cross-correlation to obtain P-wave differential time, 3) the moving-time window analysis to estimate the S-differential time. Kato et al. (2010, GRL) have estimated the Vp/Vs ratios for a few similar earthquake clusters from the Wakayama data set, by a conventional approach to obtain differential times. We find that the resulting Vp/Vs ratios from our approach for the same earthquake clusters are comparable with those obtained from Kato et al. (2010, GRL). We show that the moving-window cross-correlation technique effectively measures both P- and S-wave differential times for the seismograms in which the clear P and S phases are not observed. We will show spatial distributions in Vp/Vs ratios in our two target areas.

Why don't zebras have machine guns? Adaptation, selection, and constraints in evolutionary theory.

PubMed

Shanahan, Timothy

2008-03-01

In an influential paper, Stephen Jay Gould and Richard Lewontin (1979) contrasted selection-driven adaptation with phylogenetic, architectural, and developmental constraints as distinct causes of phenotypic evolution. In subsequent publications Gould (e.g., 1997a,b, 2002) has elaborated this distinction into one between a narrow "Darwinian Fundamentalist" emphasis on "external functionalist" processes, and a more inclusive "pluralist" emphasis on "internal structuralist" principles. Although theoretical integration of functionalist and structuralist explanations is the ultimate aim, natural selection and internal constraints are treated as distinct causes of evolutionary change. This distinction is now routinely taken for granted in the literature in evolutionary biology. I argue that this distinction is problematic because the effects attributed to non-selective constraints are more parsimoniously explained as the ordinary effects of selection itself. Although it may still be a useful shorthand to speak of phylogenetic, architectural, and developmental constraints on phenotypic evolution, it is important to understand that such "constraints" do not constitute an alternative set of causes of evolutionary change. The result of this analysis is a clearer understanding of the relationship between adaptation, selection and constraints as explanatory concepts in evolutionary theory.

Pathogenic Chlamydia Lack a Classical Sacculus but Synthesize a Narrow, Mid-cell Peptidoglycan Ring, Regulated by MreB, for Cell Division

PubMed Central

Packiam, Mathanraj; Hsu, Yen-Pang; Tekkam, Srinivas; Hall, Edward; Rittichier, Jonathan T.; VanNieuwenhze, Michael; Brun, Yves V.; Maurelli, Anthony T.

2016-01-01

The peptidoglycan (PG) cell wall is a peptide cross-linked glycan polymer essential for bacterial division and maintenance of cell shape and hydrostatic pressure. Bacteria in the Chlamydiales were long thought to lack PG until recent advances in PG labeling technologies revealed the presence of this critical cell wall component in Chlamydia trachomatis. In this study, we utilize bio-orthogonal D-amino acid dipeptide probes combined with super-resolution microscopy to demonstrate that four pathogenic Chlamydiae species each possess a ≤ 140 nm wide PG ring limited to the division plane during the replicative phase of their developmental cycles. Assembly of this PG ring is rapid, processive, and linked to the bacterial actin-like protein, MreB. Both MreB polymerization and PG biosynthesis occur only in the intracellular form of pathogenic Chlamydia and are required for cell enlargement, division, and transition between the microbe’s developmental forms. Our kinetic, molecular, and biochemical analyses suggest that the development of this limited, transient, PG ring structure is the result of pathoadaptation by Chlamydia to an intracellular niche within its vertebrate host. PMID:27144308

Pathogenic Chlamydia Lack a Classical Sacculus but Synthesize a Narrow, Mid-cell Peptidoglycan Ring, Regulated by MreB, for Cell Division.

PubMed

Liechti, George; Kuru, Erkin; Packiam, Mathanraj; Hsu, Yen-Pang; Tekkam, Srinivas; Hall, Edward; Rittichier, Jonathan T; VanNieuwenhze, Michael; Brun, Yves V; Maurelli, Anthony T

2016-05-01

The peptidoglycan (PG) cell wall is a peptide cross-linked glycan polymer essential for bacterial division and maintenance of cell shape and hydrostatic pressure. Bacteria in the Chlamydiales were long thought to lack PG until recent advances in PG labeling technologies revealed the presence of this critical cell wall component in Chlamydia trachomatis. In this study, we utilize bio-orthogonal D-amino acid dipeptide probes combined with super-resolution microscopy to demonstrate that four pathogenic Chlamydiae species each possess a ≤ 140 nm wide PG ring limited to the division plane during the replicative phase of their developmental cycles. Assembly of this PG ring is rapid, processive, and linked to the bacterial actin-like protein, MreB. Both MreB polymerization and PG biosynthesis occur only in the intracellular form of pathogenic Chlamydia and are required for cell enlargement, division, and transition between the microbe's developmental forms. Our kinetic, molecular, and biochemical analyses suggest that the development of this limited, transient, PG ring structure is the result of pathoadaptation by Chlamydia to an intracellular niche within its vertebrate host.

The guanosine nucleotide (p)ppGpp initiates development and A-factor production in myxococcus xanthus.

PubMed

Harris, B Z; Kaiser, D; Singer, M

1998-04-01

Guanosine 3'-di-5'-(tri)di-phosphate nucleotides [(p)ppGpp], synthesized in response to amino acid limitation, induce early gene expression leading to multicellular fruiting body formation in Myxococcus xanthus. A mutant (DK527) that fails to accumulate (p)ppGpp in response to starvation was found to be blocked in development prior to aggregation. By use of a series of developmentally regulated Tn5lac transcriptional fusion reporters, the time of developmental arrest in DK527 was narrowed to within the few hours of development, the period of starvation recognition. The mutant is also defective in the production of A-factor, an early extracellular cell-density signal. The relA gene from Escherichia coli, which encodes a ribosome-dependent (p)ppGpp synthetase, rescues this mutant. We also demonstrate that inactivation of the M. xanthus relA homolog blocks development and the accumulation of (p)ppGpp. Moreover, the wild-type allele of Myxococcus relA rescues DK527. These observations support a model in which accumulation of (p)ppGpp, in response to starvation, initiates the program of fruiting body development, including the production of A-factor.

A possible upgrade of FLASH for harmonic lasing down to 1.3 nm

NASA Astrophysics Data System (ADS)

Schneidmiller, E. A.; Yurkov, M. V.

2013-07-01

We propose the 3rd harmonic lasing in a new FLASH undulator as a way to produce intense, narrow-band, and stable SASE radiation down to 1.3 nm with the present accelerator energy of 1.25 GeV. To provide optimal conditions for harmonic lasing, we suggest to suppress the fundamental with the help of a special set of phase shifters. We rely on the standard technology of gap-tunable planar hybrid undulators, and choose the period of 2.3 cm and the minimum gap of 0.9 cm; total length of the undulator system is 34.5 m. With the help of numerical simulations we demonstrate that the 3rd harmonic lasing at 1.3 nm provides peak power at a gigawatt level and the narrow intrinsic bandwidth, 0.1% (FWHM). Pulse duration can be controlled in the range of a few tens of femtoseconds, and the peak brilliance reaches the value of 1031 photons/(s mrad2 mm2 0.1% BW). With the given undulator design, a standard option of lasing at the fundamental wavelength to saturation is possible through the entire water window and at longer wavelengths. In this paper we briefly consider additional options such as polarization control, bandwidth reduction, self-seeding, X-ray pulse compression, and two-color operation. We also discuss possible technical issues and backup solutions.

Multiscale models and stochastic simulation methods for computing rare but key binding events in cell biology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerrier, C.; Holcman, D., E-mail: david.holcman@ens.fr; Mathematical Institute, Oxford OX2 6GG, Newton Institute

The main difficulty in simulating diffusion processes at a molecular level in cell microdomains is due to the multiple scales involving nano- to micrometers. Few to many particles have to be simulated and simultaneously tracked while there are exploring a large portion of the space for binding small targets, such as buffers or active sites. Bridging the small and large spatial scales is achieved by rare events representing Brownian particles finding small targets and characterized by long-time distribution. These rare events are the bottleneck of numerical simulations. A naive stochastic simulation requires running many Brownian particles together, which is computationallymore » greedy and inefficient. Solving the associated partial differential equations is also difficult due to the time dependent boundary conditions, narrow passages and mixed boundary conditions at small windows. We present here two reduced modeling approaches for a fast computation of diffusing fluxes in microdomains. The first approach is based on a Markov mass-action law equations coupled to a Markov chain. The second is a Gillespie's method based on the narrow escape theory for coarse-graining the geometry of the domain into Poissonian rates. The main application concerns diffusion in cellular biology, where we compute as an example the distribution of arrival times of calcium ions to small hidden targets to trigger vesicular release.« less

A polarization independent electromagnetically induced transparency-like metamaterial with large group delay and delay-bandwidth product

NASA Astrophysics Data System (ADS)

Bagci, Fulya; Akaoglu, Baris

2018-05-01

In this study, a classical analogue of electromagnetically induced transparency (EIT) that is completely independent of the polarization direction of the incident waves is numerically and experimentally demonstrated. The unit cell of the employed planar symmetric metamaterial structure consists of one square ring resonator and four split ring resonators (SRRs). Two different designs are implemented in order to achieve a narrow-band and wide-band EIT-like response. In the unit cell design, a square ring resonator is shown to serve as a bright resonator, whereas the SRRs behave as a quasi-dark resonator, for the narrow-band (0.55 GHz full-width at half-maximum bandwidth around 5 GHz) and wide-band (1.35 GHz full-width at half-maximum bandwidth around 5.7 GHz) EIT-like metamaterials. The observed EIT-like transmission phenomenon is theoretically explained by a coupled-oscillator model. Within the transmission window, steep changes of the phase result in high group delays and the delay-bandwidth products reach 0.45 for the wide-band EIT-like metamaterial. Furthermore, it has been demonstrated that the bandwidth and group delay of the EIT-like band can be controlled by changing the incidence angle of electromagnetic waves. These features enable the proposed metamaterials to achieve potential applications in filtering, switching, data storing, and sensing.

Periconceptional maternal micronutrient supplementation is associated with widespread gender related changes in the epigenome: a study of a unique resource in the Gambia.

PubMed

Khulan, Batbayar; Cooper, Wendy N; Skinner, Benjamin M; Bauer, Julien; Owens, Stephen; Prentice, Andrew M; Belteki, Gusztav; Constancia, Miguel; Dunger, David; Affara, Nabeel A

2012-05-01

In addition to the genetic constitution inherited by an organism, the developmental trajectory and resulting mature phenotype are also determined by mechanisms acting during critical windows in early life that influence and establish stable patterns of gene expression. This is the crux of the developmental origins of health and disease hypothesis that suggests undernutrition during gestation and infancy predisposes to ill health in later life. The hypothesis that periconceptional maternal micronutrient supplementation might affect fetal genome-wide methylation within gene promoters was explored in cord blood samples from offspring of Gambian women enrolled into a unique randomized, double blind controlled trial. Significant changes in the epigenome in cord blood DNA samples were further explored in a subset of offspring at 9 months. Gender-specific changes related to periconceptional nutritional supplementation were identified in cord blood DNA samples, some of which showed persistent changes in infant blood DNA samples. Significant effects of periconceptional micronutrient supplementation were also observed in postnatal samples which were not evident in cord blood. In this Gambian population, the increased death rate of individuals born in nutritionally poor seasons has been related to infection and it is of interest that we identified differential methylation at genes associated with defence against infection and immune response. Although the sample size was relatively small, these pilot data suggest that periconceptional nutrition in humans is an important determinant of newborn whole genome methylation patterns but may also influence postnatal developmental patterns of gene promoter methylation linking early with disease risk.

Development of auditory event-related potentials in infants prenatally exposed to methadone.

PubMed

Paul, Jonathan A; Logan, Beth A; Krishnan, Ramesh; Heller, Nicole A; Morrison, Deborah G; Pritham, Ursula A; Tisher, Paul W; Troese, Marcia; Brown, Mark S; Hayes, Marie J

2014-07-01

Developmental features of the P2 auditory ERP in a change detection paradigm were examined in infants prenatally exposed to methadone. Opiate dependent pregnant women maintained on methadone replacement therapy were recruited during pregnancy (N = 60). Current and historical alcohol and substance use, SES, and psychiatric status were assessed with a maternal interview during the third trimester. Medical records were used to collect information regarding maternal medications, monthly urinalysis, and breathalyzer to confirm comorbid drug and alcohol exposures. Between birth and 4 months infant ERP change detection performance was evaluated on one occasion with the oddball paradigm (.2 probability oddball) using pure-tone stimuli (standard = 1 kHz and oddball = 2 kHz frequency) at midline electrode sites, Fz, Cz, Pz. Infant groups were examined in the following developmental windows: 4-15, 16-32, or 33-120 days PNA. Older groups showed increased P2 amplitude at Fz and effective change detection performance at P2 not seen in the newborn group. Developmental maturation of amplitude and stimulus discrimination for P2 has been reported in developing infants at all of the ages tested and data reported here in the older infants are consistent with typical development. However, it has been previously reported that the P2 amplitude difference is detectable in neonates; therefore, absence of a difference in P2 amplitude between stimuli in the 4-15 days group may represent impaired ERP performance by neonatal abstinence syndrome or prenatal methadone exposure. © 2013 Wiley Periodicals, Inc.

Exposure to a PBDE/OH-BDE mixture alters juvenile zebrafish (Danio rerio) development

PubMed Central

Macaulay, Laura J.; Chernick, Melissa; Chen, Albert; Hinton, David E.; Bailey, Jordan M.; Kullman, Seth W.; Levin, Edward D.; Stapleton, Heather M.

2017-01-01

Polybrominated diphenyl ethers (PBDEs) and halogenated phenolic compounds (e.g., hydroxylated BDEs (OH-BDEs)) arecontaminants detected together frequently in human tissues, and are structurally similar to thyroid hormones (TH). THs partially mediate metamorphic transitions between life stages in zebrafish, making this a critical developmental window which may be uniquely vulnerable to chemicals disrupting thyroid signaling. In this study, zebrafish were exposed to 6-OH-BDE-47 (30 nM) alone or to a low (30 μg/L) or high dose (600 μg/L) mixture of PentaBDEs, 6-OH-BDE-47 (0.5–6 μg/L), & 2,4,6 tribromophenol (TBP) (5–100 μg/L) during juvenile development (9–23 days post fertilization; dpf) and evaluated for developmental endpoints mediated by TH signaling. Fish were sampled at three time points and examined for developmental and skeletal morphology, apical thyroid and skeletal gene markers, and modifications in swimming behavior (as adults). Exposure to the high mixture resulted in > 85% mortality within one week of exposure, despite being below reported acute toxicity thresholds for individual congeners. The low mixture and 6-OH-BDE-47 groups exhibited reductions in body length and delayed maturation, specifically relating to swim bladder,?, fin, and pigmentation development. Reduced skeletal ossification was also observed in 6-OH-BDE-47 treated fish. Assessment of thyroid and osteochondral gene regulatory networks demonstrated significantly increased expression of genes that regulate skeletal development and THs. Overall, these results indicate that exposures to PBDEs/OH-BDEs mixtures adversely impact zebrafish maturation during metamorphosis. PMID:27329031

There is no highly conserved embryonic stage in the vertebrates: implications for current theories of evolution and development.

PubMed

Richardson, M K; Hanken, J; Gooneratne, M L; Pieau, C; Raynaud, A; Selwood, L; Wright, G M

1997-08-01

Embryos of different species of vertebrate share a common organisation and often look similar. Adult differences among species become more apparent through divergence at later stages. Some authors have suggested that members of most or all vertebrate clades pass through a virtually identical, conserved stage. This idea was promoted by Haeckel, and has recently been revived in the context of claims regarding the universality of developmental mechanisms. Thus embryonic resemblance at the tailbud stage has been linked with a conserved pattern of developmental gene expression - the zootype. Haeckel's drawings of the external morphology of various vertebrates remain the most comprehensive comparative data purporting to show a conserved stage. However, their accuracy has been questioned and only a narrow range of species was illustrated. In view of the current widespread interest in evolutionary developmental biology, and especially in the conservation of developmental mechanisms, re-examination of the extent of variation in vertebrate embryos is long overdue. We present here the first review of the external morphology of tailbud embryos, illustrated with original specimens from a wide range of vertebrate groups. We find that embryos at the tailbud stage - thought to correspond to a conserved stage - show variations in form due to allometry, heterochrony, and differences in body plan and somite number. These variations foreshadow important differences in adult body form. Contrary to recent claims that all vertebrate embryos pass through a stage when they are the same size, we find a greater than 10-fold variation in greatest length at the tailbud stage. Our survey seriously undermines the credibility of Haeckel's drawings, which depict not a conserved stage for vertebrates, but a stylised amniote embryo. In fact, the taxonomic level of greatest resemblance among vertebrate embryos is below the subphylum. The wide variation in morphology among vertebrate embryos is difficult to reconcile with the idea of a phyogenetically-conserved tailbud stage, and suggests that at least some developmental mechanisms are not highly constrained by the zootype. Our study also highlights the dangers of drawing general conclusions about vertebrate development from studies of gene expression in a small number of laboratory species.

Embryonic critical windows: changes in incubation temperature alter survival, hatchling phenotype, and cost of development in lake whitefish (Coregonus clupeaformis).

PubMed

Mueller, Casey A; Eme, John; Manzon, Richard G; Somers, Christopher M; Boreham, Douglas R; Wilson, Joanna Y

2015-04-01

The timing, success and energetics of fish embryonic development are strongly influenced by temperature. However, it is unclear if there are developmental periods, or critical windows, when oxygen use, survival and hatchling phenotypic characteristics are particularly influenced by changes in the thermal environment. Therefore, we examined the effects of constant incubation temperature and thermal shifts on survival, hatchling phenotype, and cost of development in lake whitefish (Coregonus clupeaformis) embryos. We incubated whitefish embryos at control temperatures of 2, 5, or 8 °C, and shifted embryos across these three temperatures at the end of gastrulation or organogenesis. We assessed hatch timing, mass at hatch, and yolk conversion efficiency (YCE). We determined cost of development, the amount of oxygen required to build a unit of mass, for the periods from fertilization-organogenesis, organogenesis-fin flutter, fin flutter-hatch, and for total development. An increase in incubation temperature decreased time to 50 % hatch (164 days at 2 °C, 104 days at 5 °C, and 63 days at 8 °C), survival decreased from 55 % at 2 °C, to 38 % at 5 °C, and 17 % at 8 °C, and hatchling yolk-free dry mass decreased from 1.27 mg at 2 °C to 0.61 mg at 8 °C. Thermal shifts altered time to 50 % hatch and hatchling yolk-free dry mass and revealed a critical window during gastrulation in which a temperature change reduced survival. YCE decreased and cost of development increased with increased incubation temperature, but embryos that hatched at 8 °C and were incubated at colder temperatures during fertilization-organogenesis had reduced cost. The relationship between cost of development and temperature was altered during fin flutter-hatch, indicating it may be a critical window during which temperature has the greatest impact on energetic processes. The increase in cost of development with an increase in temperature has not been documented in other fishes and suggests whitefish embryos are more energy efficient at colder temperatures.

Critical windows in embryonic development: Shifting incubation temperatures alter heart rate and oxygen consumption of Lake Whitefish (Coregonus clupeaformis) embryos and hatchlings.

PubMed

Eme, J; Mueller, C A; Manzon, R G; Somers, C M; Boreham, D R; Wilson, J Y

2015-01-01

Critical windows are periods of developmental susceptibility when the phenotype of an embryonic, juvenile or adult animal may be vulnerable to environmental fluctuations. Temperature has pervasive effects on poikilotherm physiology, and embryos are especially vulnerable to temperature shifts. To identify critical windows, we incubated whitefish embryos at control temperatures of 2°C, 5°C, or 8°C, and shifted treatments among temperatures at the end of gastrulation or organogenesis. Heart rate (fH) and oxygen consumption ( [Formula: see text] ) were measured across embryonic development, and [Formula: see text] was measured in 1-day old hatchlings. Thermal shifts, up or down, from initial incubation temperatures caused persistent changes in fH and [Formula: see text] compared to control embryos measured at the same temperature (2°C, 5°C, or 8°C). Most prominently, when embryos were measured at organogenesis, shifting incubation temperature after gastrulation significantly lowered [Formula: see text] or fH. Incubation at 2°C or 5°C through gastrulation significantly lowered [Formula: see text] (42% decrease) and fH (20% decrease) at 8°C, incubation at 2°C significantly lowered [Formula: see text] (40% decrease) and fH (30% decrease) at 5°C, and incubation at 5°C and 8°C significantly lowered [Formula: see text] at 2°C (27% decrease). Through the latter half of development, [Formula: see text] and fH in embryos were not different from control values for thermally shifted treatments. However, in hatchlings measured at 2°C, [Formula: see text] was higher in groups incubated at 5°C or 8°C through organogenesis, compared to 2°C controls (43 or 65% increase, respectively). Collectively, these data suggest that embryonic development through organogenesis represents a critical window of embryonic and hatchling phenotypic plasticity. This study presents an experimental design that identified thermally sensitive periods for fish embryos. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

Recent developments and applications of the SEC vidicon for astronomy

NASA Technical Reports Server (NTRS)

Zucchino, P.; Lowrance, J. L.

1971-01-01

The engineering development of the SEC vidicon as an astronomical sensor has continued in parallel with its operational use. One scientific application was the six hour exposure of the quasar PHL-957 at the Coude spectrograph of the 200-inch Hale telescope. The developmental effort includes both the enhancement of the basic attributes that make the SEC an appropriate sensor, namely, high quantum efficiency, low threshold, and long integration; as well as work to broaden its scientific usefulness, such as the development of a MgF2 photocathode window for vacuum ultraviolet sensitivity, and a permanent magnet focus design for thermal compatibility with proposed large space telescopes. Additional details on the characteristics of the SEC tube are discussed, as well as plans to make a larger and higher resolution version.

Maternal obesity and prenatal programming.

PubMed

Elshenawy, Summer; Simmons, Rebecca

2016-11-05

Obesity is a significant and increasing public health concern in the United States and worldwide. Clinical and epidemiological evidence clearly shows that genetic and environmental factors contribute to the increased susceptibility of humans to obesity and its associated comorbidities; the interplay of these factors is explained by the concept of epigenetics. The impact of maternal obesity goes beyond the newborn period; fetal programming during the critical window of pregnancy, can have long term detrimental effects on the offspring as well as future generations. Emerging evidence is uncovering a link between the clinical and molecular findings in the offspring with epigenetic changes in the setting of maternal obesity. Research targeted towards reducing the transgenerational propagation and developmental programming of obesity is vital in reducing the increasing rates of disease. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.