Les effets des interfaces sur les proprietes magnetiques et de transport des multicouches nickel/iron et cobalt/silver

NASA Astrophysics Data System (ADS)

Veres, Teodor

Cette these est consacree a l'etude de l'evolution structurale des proprietes magnetiques et de transport des multicouches Ni/Fe et nanostructures a base de Co et de l'Ag. Dans une premiere partie, essentiellement bibliographique, nous introduisons quelques concepts de base relies aux proprietes magnetiques et de transport des multicouches metalliques. Ensuite, nous presentons une breve description des methodes d'analyse des resultats. La deuxieme partie est consacree a l'etude des proprietes magnetiques et de transport des multicouches ferromagnetiques/ferromagnetiques Ni/Fe. Nous montrerons qu'une interpretation coherente de ces proprietes necessite la prise en consideration des effets des interfaces. Nous nous attacherons a mettre en evidence, a evaluer et a etudier les effets de ces interfaces ainsi que leur evolution, et ce, suite a des traitements thermiques tel que le depot a temperature elevee et l'irradiation ionique. Les analyses correlees de la structure et de la magnetoresistance nous permettront d'emettre des conclusions sur l'influence des couches tampons entre l'interface et le substrat ainsi qu'entre les couches elles-memes sur le comportement magnetique des couches F/F. La troisieme partie est consacree aux systemes a Magneto-Resistance Geante (MRG) a base de Co et Ag. Nous allons etudier l'evolution de la microstructure suite a l'irradiation avec des ions Si+ ayant une energie de 1 MeV, ainsi que les effets de ces changements sur le comportement magnetique. Cette partie debutera par l'analyse des proprietes d'une multicouche hybride, intermediaire entre les multicouches et les materiaux granulaires. Nous analyserons a l'aide des mesures de diffraction, de relaxation superparamagnetique et de magnetoresistance, les evolutions structurales produites par l'irradiation ionique. Nous etablirons des modeles qui nous aideront a interpreter les resultats pour une serie des multicouches qui couvrent un large eventail de differents comportements magnetiques et ceci en fonction de l'epaisseur de la couche magnetique de Co. Nous verrons que dans ces systemes les effets de l'irradiation ionique sont fortement influences par l'energie de surface ainsi que par l'enthalpie de formation, largement positive pour le systeme Co/Ag.

Building Vocabulary of English Learners with Reading Disabilities through Computer-Assisted Morphology Instruction

ERIC Educational Resources Information Center

Lo, Ya-yu; Anderson, Adrienne L.; Bunch-Crump, Kimberly

2017-01-01

Many educators in public schools in the United States experience challenges in meeting the unique needs of the growing population of English learners who must simultaneously attain academic skills while acquiring English language proficiency. Such unique needs intensify for English learners with reading disabilities. Morphological awareness is key…

Morphology control, defect engineering and photoactivity tuning of ZnO crystals by graphene oxide--a unique 2D macromolecular surfactant.

PubMed

Pan, Xiaoyang; Yang, Min-Quan; Xu, Yi-Jun

2014-03-28

Zinc oxide (ZnO) nanostructured materials have received significant attention because of their unique physicochemical and electronic properties. In particular, the functional properties of ZnO are strongly dependent on its morphology and defect structure, particularly for a semiconductor ZnO-based photocatalyst. Here, we demonstrate a simple strategy for simultaneous morphology control, defect engineering and photoactivity tuning of semiconductor ZnO by utilizing the unique surfactant properties of graphene oxide (GO) in a liquid phase. By varying the amount of GO added during the synthesis process, the morphology of ZnO gradually evolves from a one dimensional prismatic rod to a hexagonal tube-like architecture while GO is converted into reduced GO (RGO). In addition, the introduction of GO can create oxygen vacancies in the lattice of ZnO crystals. As a result, the absorption edge of the wide band gap semiconductor ZnO is effectively extended to the visible light region, which thus endows the RGO-ZnO nanocomposites with visible light photoactivity; in contrast, the bare ZnO nanorod is only UV light photoactive. The synergistic integration of the unique morphology and the presence of oxygen vacancies imparts the RGO-ZnO nanocomposite with remarkably enhanced visible light photoactivity as compared to bare ZnO and its counterpart featuring different structural morphologies and the absence of oxygen vacancies. Our promising results highlight the versatility of the 2D GO as a solution-processable macromolecular surfactant to fabricate RGO-semiconductor nanocomposites with tunable morphology, defect structure and photocatalytic performance in a system-materials-engineering way.

Template-directed control of crystal morphologies.

PubMed

Meldrum, Fiona C; Ludwigs, Sabine

2007-02-12

Biominerals are characterised by unique morphologies, and it is a long-term synthetic goal to reproduce these synthetically. We here apply a range of templating routes to investigate whether a fascinating category of biominerals, the single crystals with complex forms, can be produced using simple synthetic methods. Macroporous crystals with sponge-like morphologies identical to that of sea urchin skeletal plates were produced on templating with a sponge-like polymer membrane. Similarly, patterning of individual crystal faces was achieved from the micrometer to nanometer scale through crystallisation on colloidal particle monolayers and patterned polymer thin films. These experiments demonstrate the versatility of a templating approach to producing single crystals with unique morphologies.

Assessment of the effect of No Stay, Bent Stay or Straight Stay when the Clothe the Soldier Rucksack is Worn with the Fragmentation Vest

DTIC Science & Technology

2006-02-01

effets de différents renforts de sac à dos (renforts droits, renforts courbés et aucun renfort) sur la...supérieures au seuil de tolérance de la peau et des muscles sous-jacents, et elles pourraient causer des lésions sur la peau et des ecchymoses. Assessment...présente évaluation portait sur cette pratique et visait à déterminer les effets de différents renforts de sac à dos (renforts droits, renforts courbés

A Survey of Serious Aircraft Accidents Involving Fatigue Fracture. Volume 1. Fixed-Wing Aircraft (Etude sur des Accidents Importants d’Avions du aux Effets des Fractures de Fatigue. Volume 1. Effets sur des Avions).

DTIC Science & Technology

1983-04-01

Bureau of Standards. NTS3 National Transportation Safety Board (USA). NTSB AAR NTSB Aircraft Accident Report. NZ AAR New Zealand Aircraft Accident Report...NZ AI New Zealand Accident Investigation Bureau. 0 -5- RAN Royal Australian Navy RAAI Royal Australian Air Force RAF Royal Air Force, UK S Substantial...Ice land Iraq Ireland Jamaica (1966 -1981) Japan (1973 - Feb. 81) Kenya Lethoso Malaysia Ma law i Mal ta Mexico Netherlands New Zealand Norway

Evaluation d'impact sur la santé et évaluation d'impact sur l'équité en santé : éventail de pratiques et questions de recherche.

PubMed

Villeval, Mélanie; Bidault, Elsa; Lang, Thierry

2016-09-01

L'Evaluation d'Impact sur la Santé (EIS) se développe au niveau international et est encore au stade émergent en France. Elle vise à évaluer les effets positifs et négatifs potentiels d'un projet, d'un programme ou d'une politique sur la santé. L'objectif est de produire des recommandations en direction des décideurs, afin d'en maximiser les effets positifs et d'en diminuer les effets négatifs. L'EIS est un moyen particulièrement intéressant d'action sur les déterminants de la santé au-delà des comportements individuels et du système de santé. Les politiques de logement, de transport, de solidarité, économiques, etc. ont, en effet, des impacts souvent non prévus sur la santé. Au-delà des effets sur la santé, l'EIS doit aussi permettre d'apprécier la distribution de ces effets dans la population.Si la préoccupation pour l'équité en santé est centrale dans l'EIS, elle reste cependant difficilement traduite en pratique. Face à cette difficulté, des démarches d'évaluation d'impact ont été développées pour renforcer la prise en compte de l'équité à chaque étape de l'EIS ou « Equity Focused Health Impact Assessment », ou prendre en compte les impacts sur les inégalités de santé de façon spécifique. Ainsi, l'Evaluation de l'Impact sur l'Equité en Santé (EIES) semble, par exemple, particulièrement intéressante pour évaluer l'impact sur les inégalités de projets dans le champ sanitaire.L'EIS et l'EIES posent de nombreuses questions de recherche, notamment autour de la réunion, dans une même démarche, du politique, du citoyen et de l'expert. La participation des populations vulnérables potentiellement affectées par la politique évaluée est une valeur centrale de l'EIS, mais pose des questions d'acceptabilité sociale. La collaboration avec les décideurs politiques est également un enjeu majeur. Les difficultés méthodologiques, notamment de quantification des impacts, peuvent constituer des freins à la promotion de la démarche auprès des décideurs. © The Author(s) 2015.

A Quantile Regression Approach to Understanding the Relations Between Morphological Awareness, Vocabulary, and Reading Comprehension in Adult Basic Education Students

PubMed Central

Tighe, Elizabeth L.; Schatschneider, Christopher

2015-01-01

The purpose of this study was to investigate the joint and unique contributions of morphological awareness and vocabulary knowledge at five reading comprehension levels in Adult Basic Education (ABE) students. We introduce the statistical technique of multiple quantile regression, which enabled us to assess the predictive utility of morphological awareness and vocabulary knowledge at multiple points (quantiles) along the continuous distribution of reading comprehension. To demonstrate the efficacy of our multiple quantile regression analysis, we compared and contrasted our results with a traditional multiple regression analytic approach. Our results indicated that morphological awareness and vocabulary knowledge accounted for a large portion of the variance (82-95%) in reading comprehension skills across all quantiles. Morphological awareness exhibited the greatest unique predictive ability at lower levels of reading comprehension whereas vocabulary knowledge exhibited the greatest unique predictive ability at higher levels of reading comprehension. These results indicate the utility of using multiple quantile regression to assess trajectories of component skills across multiple levels of reading comprehension. The implications of our findings for ABE programs are discussed. PMID:25351773

Les effets bénéfiques de l'accompagnement du patient cancéreux: particularités du Maroc

PubMed Central

Lkhoyaali, Sihame; Aitelhaj, Meryem; Errihani, Hassan

2014-01-01

Au Maroc la majorité des patients âgés cancéreux sont pris en charge par leurs proches l'accompagnement des patients est à l'origine de conséquences émotionnelles psychiques et financières négatives mais en contrepartie il est à l'origine de plusieurs effets bénéfiques à savoir un resserrement des liens familiaux, une surestime du soi et il est la source d'un bien-être affectif et spirituel qui permet de faire face à la maladie. PMID:25722766

Development of a Dynamic Biomechanical Model for Load Carriage: Phase IV Part C1: Assessment of Pressure Measurement Systems on Flat Surfaces for use in Human Load Carriage

DTIC Science & Technology

2005-08-01

iv Sommaire Les études sur les effets de la pression de contact produite par une charge d’un sac à dos sont essentielles, étant...mobilité des soldats et amenuiser leur capacité de combat. Afin de mieux comprendre les effets de la pression d’un sac à dos sur le confort et la... de mesure de pression qui pourraient être utilisés pour établir les valeurs de tolérance de la peau aux pressions durant le transport d’une charge

Consequences experimentales des effets des fluctuations du vide sur la fluorescence parametrique et la generation du second harmonique en milieu confine

NASA Astrophysics Data System (ADS)

Robichaud, Luc

Les fluctuations du vide, qui consistent en l'apparition momentanee de particules, ce qui est permit par le principe d'incertitude de Heisenberg, joue un role primordial dans les processus photoniques, en particulier les processus non-lineaires. Par la manipulation de ces fluctuations du vide a l'aide de confinement optique, on retrouve deux phenomenes particuliers : l'intensification de la fluorescence parametrique (Walker, 2008) et l'inhibition de la generation du second harmonique (Collette, 2013). Dans ce travail, on presente les resultats dans le cas classique ; c'est-a-dire sans fluctuations du vide et confinement. Par la suite, on presente les effets des fluctuations du vide et du confinement, ce qui mene aux deux effets mentionnes. Dans le cas de la fluorescence parametrique, le bruit quantique sur le champ interne et externe est calcule, le role du desaccord de phase dans le modele est expose et une generalisation tridimensionnelle est etudiee afin de generaliser la conception du modele d'un cas unidimensionnel a un cas tridimensionnel planaire. Dans le cas de la generation du second harmonique, les difficultes d'un modele purement tridimensionnel sont exposees et ensuite le cas limite planaire est etudie.

Imaging Implicit Morphological Processing: Evidence from Hebrew

ERIC Educational Resources Information Center

Bick, Atira S.; Frost, Ram; Goelman, Gadi

2010-01-01

Is morphology a discrete and independent element of lexical structure or does it simply reflect a fine-tuning of the system to the statistical correlation that exists among orthographic and semantic properties of words? Hebrew provides a unique opportunity to examine morphological processing in the brain because of its rich morphological system.…

A Quantile Regression Approach to Understanding the Relations Among Morphological Awareness, Vocabulary, and Reading Comprehension in Adult Basic Education Students.

PubMed

Tighe, Elizabeth L; Schatschneider, Christopher

2016-07-01

The purpose of this study was to investigate the joint and unique contributions of morphological awareness and vocabulary knowledge at five reading comprehension levels in adult basic education (ABE) students. We introduce the statistical technique of multiple quantile regression, which enabled us to assess the predictive utility of morphological awareness and vocabulary knowledge at multiple points (quantiles) along the continuous distribution of reading comprehension. To demonstrate the efficacy of our multiple quantile regression analysis, we compared and contrasted our results with a traditional multiple regression analytic approach. Our results indicated that morphological awareness and vocabulary knowledge accounted for a large portion of the variance (82%-95%) in reading comprehension skills across all quantiles. Morphological awareness exhibited the greatest unique predictive ability at lower levels of reading comprehension whereas vocabulary knowledge exhibited the greatest unique predictive ability at higher levels of reading comprehension. These results indicate the utility of using multiple quantile regression to assess trajectories of component skills across multiple levels of reading comprehension. The implications of our findings for ABE programs are discussed. © Hammill Institute on Disabilities 2014.

Gravitational lensing in observational cosmology

NASA Astrophysics Data System (ADS)

Nottale, L.

This paper reviews some previous theoretical and observational results concerning the various effects of gravitational lensing, and also presents still unpublished results in this field. The theoretical section deals with the Optical Scalar Equation (OSE) approach. We recall the form of these equations, which relate the deformations of the cross sectional area of a light beam to the material and energetic distribution it encounters, via the two basic contributions to lensing, the matter or Ricci term and the shear term. The introduction of a new distance, the optical distance, allows to write the OSE in a simplified way from which new solutions are easily derived. We demonstrate here that a general form may be obtained for the amplification formula in the exact relativistic treatment, provided the Universe is assumed to be Friedmannian in the mean. New results are also presented concerning the probability distribution of amplifications, the relation from matter term to shear terms (the first ones give the mean of the second ones) and the problem of energy conservation. We recall how our method let to an analytical formula yielding the amplification by any number of lenses placed anywhere along the line of sight and present new general solutions for lensing by large scale density inhomogeneities. The gravitational redshift effects are also considered, either due to the crossing by photons of inhomogeneities, or intrinsic to them ; generalized solutions to the last problem are given. Some observational evidence concerning various lensing effects, either statistical or applying to individual sources, are considered. We first recall how the dependence of the amplification formula on the various physical parameters points towards the optimisation of lensing by very rich clusters of galaxies lying at redshifts around 0.7, which may give rise to very large amplifications for reasonable values of the density parameter. Recent results concerning a statistical effect of amplification of Brightest Cluster Galaxies by foreground clusters are analysed, including the discussion of a selection effect precisely due to gravitational luminosity amplification. It results in an artificial increase of the deceleration parameter of the Universe measured from the Hubble diagram of these objects. We recall our proposal that the sample of distant 3C radiogalaxies of redshift > 1 is strongly perturbed by lensing effects, mostly by foreground clusters of galaxies (i.e. only the luminosity is changed without image multiplication), but also for some objects by galaxies, producing gravitational mirages. The case of 3C324, for which definite evidence for multiple imaging has been recently obtained, is described, including detailed modelling of the lensing configuration. We present a highly significant statistical effect of lensing on absorption line QSOs due to matter lying at the absorption redshifts. Microlensing is also considered, and we recall our recent proposal that the variability of some among the OVV QSOs turning to BL Lac at maximum brightness, like the eruptive object 0846 +51W1, is a consequence of microlensing by stars or compact objects constituting foreground galaxy halos. Finally, discrepant redshift associations are considered. We recall how the case of anomalous quintets of galaxies have been explained by the gravitational lensing effects of quartets halos on background galaxies. Then we present evidence that the Arp QSO-galaxy associations may be the result of the combined lensing effects of several superposed galaxies, groups and clusters. Cet article présente une revue de certains résultats théoriques et observationnels concernant les divers effets de lentille gravitationnelle, complétée par des résultats nouveaux non encore publiés. Dans la partie théorique, nous considérons essentiellement l'approche relativiste employant les équations scalaires optiques. La forme de ces équations est rappelée : elles relient les diverses déformations subies par la section d'un faisceau lumineux au cours de sa propagation, à la distribution matérielle et énergétique qu'il rencontre sur son trajet entre la source et l'observateur. Les deux contributions aux effets d'optique apparaissant dans ces équations (et leurs solutions) sont les termes de matière et les termes de cisaillement. Nous montrons comment une nouvelle distance peut être introduite, la distance optique, en fonction de laquelle les équations se simplifient et de nouvelles solutions analytiques peuvent être établies. En particulier, nous démontrons que la formule d'amplification gravitationnelle peut s'écrire sous une forme très générale sous la simple hypothèse que l'Univers est en moyenne de type Friedmann-Robertson-Walker. De nouveaux résultats sont aussi présentés concernant la distribution de probabilité des amplifications, les rapports entre termes de matière et termes de cisaillement (les premiers donnant la moyenne des seconds), et le problème de la conservation de l'énergie. Nous rappelons comment une formule analytique peut être obtenue pour des amplifications multiples et présentons des solutions nouvelles au problème de l'amplification par des hétérogénéités à très grande échelle. Enfin, les effets de décalages spectraux gravitationnels sont aussi considérés, qu'ils soient dus à des effets de traversée d'excès de densité, ou intrinsèques à ceux-ci ; dans ce dernier cas, une généralisation de solutions déjà connues est proposée. On considère ensuite le problème de la mise en évidence observationnelle des divers effets d'optique gravitationnelle, qu'ils soient de nature statistique ou qu'ils concernent des objets individuels. A la suite d'une analyse décrivant la dépendance de la formule d'amplification en fonction des différents paramètres y intervenant, nous insistons tout particulièrement sur le rôle cosmologique que jouent probablement les amas de galaxies très riches de décalages spectraux autour de 0,7 qui peuvent donner lieu à des amplifications quasi-infinies. La mise en évidence récente d'un effet statistique d'amplification par des amas d'avant-plan sur les galaxies les plus brillantes des amas est rappelée, ainsi que celle d'un important effet de sélection observationnel, précisément dû aux amplifications, qui augmente artificiellement la valeur de q0 mesurée à partir du diagramme de Hubble. L'extrapolation de cet effet à des objets plus lointains nous a conduit à proposer que les radiogalaxies lointaines du catalogue 3C de z < 1 étaient fortement affectées par les effets de lentille gravitationnelle, essentiellement par les amas (qui les amplifient la plupart du temps sans multiplication d'image), mais aussi dans certains cas par des galaxies qui peuvent alors provoquer des effets de mirage. Le cas de 3C324, pour lequel des preuves observationelles de multiplication d'image ont été récemment obtenues, est analysé en particulier ; un modèle détaillé en est présenté. Un autre effet statistique récemment démontré concerne les quasars à raies d'absorption, dont la luminosité est fortement corrélée à l'amplification prédite par de la matière située aux décalages spectraux d'absorption. On considère également les effets de microlentille : nous rappelons notre proposition récente que la variabilité de certains OVVs tels que le BL Lac éruptif 0846 + 51W1 est une conséquence du passage d'étoiles ou d'objets compacts du halo de galaxies intervenantes devant les régions centrales d'un quasar. Le lien entre effets d'optique gravitationnelle et associations de décalages spectraux discordants est évoqué. Le cas des quintets de galaxies discordant a été récemment expliqué par les effets (amplification, agrandissement, changement de densité superficielle d'objets lointains) des halos de groupes compacts de galaxies. Nous démontrons pour finir que les associations QSOsgalaxies de Arp peuvent s'expliquer par les effets de lentille gravitationnelle combinés de plusieurs galaxies, groupes et amas vus en superposition.

Development of a Dynamic Biomechanical Model for Load Carriage: Phase V: Development of the Biomechanical Model by Means of the Portable Measurement System

DTIC Science & Technology

2005-05-01

Résumé La performance opérationnelle des soldats dépend d’un certain nombre de facteurs, dont la charge de travail physiologique, les effets ...particulièrement à la charge de travail physiologique et aux effets biomécaniques, et à perfectionner la mise au point d’un modèle biomécanique dynamique (DBM...on a créé une couche de peau possédant des propriétés appropriées pour le modèle de torse et on a réalisé la modélisation de tous les composants

Morphological Decomposition in Reading Hebrew Homographs

ERIC Educational Resources Information Center

Miller, Paul; Liran-Hazan, Batel; Vaknin, Vered

2016-01-01

The present work investigates whether and how morphological decomposition processes bias the reading of Hebrew heterophonic homographs, i.e., unique orthographic patterns that are associated with two separate phonological, semantic entities depicted by means of two morphological structures (linear and nonlinear). In order to reveal the nature of…

Comparaison des effets des irradiations γ, X et UV dans les fibres optiques

NASA Astrophysics Data System (ADS)

Girard, S.; Ouerdane, Y.; Baggio, J.; Boukenter, A.; Meunier, J.-P.; Leray, J.-L.

2005-06-01

Les fibres optiques présentent de nombreux avantages incitant à les intégrer dans des applications devant résister aux environnements radiatifs associés aux domaines civil, spatial ou militaire. Cependant, leur exposition à un rayonnement entraîne la création de défauts ponctuels dans la silice amorphe pure ou dopée qui constitue les différentes parties de la fibre optique. Ces défauts causent, en particulier, une augmentation transitoire de l'atténuation linéique des fibres optiques responsable de la dégradation voire de la perte du signal propagé dans celles-ci. Dans cet article, nous comparons les effets de deux types d'irradiation: une impulsion X et une dose γ cumulée. Les effets de ces irradiations sont ensuite comparés avec ceux induits par une insolation ultraviolette (244 nm) sur les propriétés d'absorption des fibres optiques. Nous montrons qu'il existe des similitudes entre ces différentes excitations et qu'il est possible, sous certaines conditions, d'utiliser celles-ci afin d'évaluer la capacité de certaines fibres optiques à fonctionner dans un environnement nucléaire donné.

Antisuperconductors: Properties of Layered Compounds with Coupling

NASA Astrophysics Data System (ADS)

Carton, J.-P.; Lammert, P. E.; Prost, J.

1995-11-01

In this note, we consider properties of a hypothetical superconductor composed of Josephson-coupled microscopic layers with tunneling energy minimized at a phase difference of π. The non-zero phase offset in the ground state engenders an intriguing interplay between the superconductive ordering and structural lattice defects. Unusual magnetic properties are expected in the case of highly disordered crystals, which are consistent with observations of a “paramagnetic Meissner” or “Wohlleben” effect in high-T_c cuprate superconductors. Dans cette note, nous considérons les propriétés d'un supraconducteur hypothétique composé de couches microscopiques, couplées par effet Josephson, mais dont l'énergie de couplage est minimisée pour une différence de phase de π. L'état de base a des propriétés fascinantes dues à l'effet combiné de l'ordre supraconducteur et des défauts structuraux du cristal. Dans le cas de cristaux très désordonnés, on attend des propriétés magnétiques exceptionnelles, qui sont compatibles avec les observations dans quelques supraconducteurs cuprate haute-T_c d'un effet “Meissner paramagnétique” ou “Wohlleben”.

Etude par resistivite electrique du comportement d'un alliage amorphe Fe 40Ni 38Mo 4B 18 deforme par traction

NASA Astrophysics Data System (ADS)

Hoang, Long Phan; Sacovy, Paulette; Delaplace, Jean

1983-02-01

Des rubans d'alliages amorphes Metglas du type Fe 40Ni 38Mo 4B 18 à l'état brut de trempe ont été déformés par traction à la température ambiante et l'on a suivi les variations de la résistance électrique des échantillons au cours de la déformation. Il ressort de ces essais que la déformation plastique qui est de l'ordre de 0.5% avant rupture ne se produit pas de faĉon homogène dans l'échantillon. Les mesures électriques effectuées au cours de la déformation mettent en évidence dans le domaine élastique un effet d'élastorésistance, relativement important ( K ≠ 1); elles montrent que dans le domaine plastique la déformation permanente des échantillons s'accompagne d'une diminution de la résistivité électrique du matériau. Deux hypothèses sont discutées pour expliquer cet effet inattendu, l'un qui fait appel à l'existence de volumes libres, l'autre qui suppose une cristallisation localisée du matériau sous l'effet de la contrainte.

Evaluating the Effectiveness of a Morphological Awareness Intervention: A Pilot Study

ERIC Educational Resources Information Center

Brimo, Danielle

2016-01-01

Researchers have established that morphological awareness is an important skill because it contributes unique variance to word-level reading and reading comprehension; however, few studies include students with reading disorders. The purpose of this pilot study was to investigate whether training morphological awareness would improve morphological…

Nanoparticules d'or: De l'imagerie par resonance magnetique a la radiosensibilisation

NASA Astrophysics Data System (ADS)

Hebert, Etienne M.

Cette thèse approfondit l'étude de nanoparticules d'or de 5 nm de diamètre recouvertes de diamideéthanethioldiethylènetriaminepentacétate de gadolinium (DTDTPA:Gd), un agent de contraste pour l'imagerie par résonance magnétique (IRM). En guise de ciblage passif, la taille des nanoparticules a été contrôlée afin d'utiliser le réseau de néovaisseaux poreux et perméable des tumeurs. De plus les tumeurs ont un drainage lymphatique déficient qui permet aux nanoparticules de demeurer plus longtemps dans le milieu interstitiel de la tumeur. Les expériences ont été effectuées sur des souris Balb/c femelles portant des tumeurs MC7-L1. La concentration de nanoparticules a pu être mesurée à l'IRM in vivo. La concentration maximale se retrouvait à la fin de l'infusion de 10 min. La concentration s'élevait à 0.3 mM dans la tumeur et de 0.12 mM dans le muscle environnant. Les nanoparticules étaient éliminées avec une demi-vie de 22 min pour les tumeurs et de 20 min pour le muscle environnant. Les nanoparticules ont été fonctionnalisées avec le peptide Tat afin de leur conférer des propriétés de ciblage actif La rétention de ces nanoparticules a ainsi été augmentée de 1600 %, passant d'une demi-vie d'élimination de 22 min à 350 min. La survie des souris a été mesurée à l'aide de courbes Kaplan-Meier et d'un modèle mathématique évalue l'efficacité de traitements. Le modèle nous permet, à l'aide de la vitesse de croissance des tumeurs et de l'efficacité des traitements, de calculer la courbe de survie des spécimens. Un effet antagoniste a été observé au lieu de l'effet synergétique attendu entre une infusion de Au@DTDTPA:Gd et l'irradiation aux rayons X. L'absence d'effet synergétique a été attribuée à l'épaisseur du recouvrement de DTDTPA:Gd qui fait écran aux électrons produits par l'or. De plus, le moyen d'ancrage du recouvrement utilise des thiols qui peuvent s'avérer être des capteurs de radicaux. De plus, contrairement a ce qui était escompté, un effet chimiothérapeutique de ces nanoparticules a été observé in vitro et in vivo. Par contre, le mécanisme précis de cet effet est encore à être expliquer, mais on sait déjà que les nanoparticules d'or affectent les fonctions des macrophages ainsi que l'angiogenèse. MOTS-CLÉS : Radiosensibilisateur, Nanoparticules d'or, Agent de contraste pour l'IRM, Électrons de basses énergies, Kaplan-Meier, Effet chimiothérapeutique.

Parametrisation D'effets Non-Standard EN Phenomenologie Electrofaible

NASA Astrophysics Data System (ADS)

Maksymyk, Ivan

Cette these pat articles porte sur la parametrisation d'effets non standard en physique electrofaible. Dans chaque analyse, nous avons ajoute plusieurs operateurs non standard au lagrangien du modele standard electrofaible. Les operateurs non standard decrivent les nouveaux effets decoulant d'un modele sous-jacent non-specefie. D'emblee, le nombre d'operateurs non standard que l'on peut inclure dans une telle analyse est illimite. Mais pour une classe specifique de modeles sous-jacents, les effets non standard peuvent etre decrits par un nombre raisonnable d'operateurs. Dans chaque analyse nous avons developpe des expressions pour des observables electrofaibles, en fonction des coefficients des operateurs nouveaux. En effectuant un "fit" statistique sur un ensemble de donnees experimentales precises, nous avons obtenu des contraintes phenomenologiques sur ces coefficients. Dans "Model-Independent Global Constraints on New Physics", nous avons adopte des hypotheses tres peu contraignantes relatives aux modeles sous-jacents. Nous avons tronque le lagrangien effectif a la dimension cinq (inclusivement). Visant la plus grande generalite possible, nous avons admis des interactions qui ne respectent pas les symetries discretes (soit C, P et CP) ainsi que des interactions qui ne conservent pas la saveur. Le lagrangien effectif contient une quarantaine d'operateurs nouveaux. Nous avons determine que, pour la plupart des coefficients des nouveaux operateurs, les contraintes sont assez serrees (2 ou 3%), mais il y a des exceptions interessantes. Dans "Bounding Anomalous Three-Gauge-Boson Couplings", nous avons determine des contraintes phenomenologiques sur les deviations des couplages a trois bosons de jauge par rapport aux interactions prescrites par le modele standard. Pour ce faire, nous avons calcule les contributions indirectes des CTBJ non standard aux observables de basse energie. Puisque le lagrangien effectif est non-renormalisable, certaines difficultes techniques se posent: pour regulariser les integrales de Feynman les chercheurs se sont generalement servi de la methode de coupure, mais cette methode peut mener a des resultats incorrects. Nous avons opte pour une technique alternative: la regularisation dimensionnelle et la "soustraction minimale avec decouplage". Dans "Beyond S, T and U" nous presentons le formalisme STUVWX, qui est une extension du formalisme STU de Peskin et Takeuchi. Ces formalismes sont bases sur l'hypothese que la theorie sous-jacente se manifeste au moyen de self -energies de bosons de jauge. Ce type d'effet s'appelle 'oblique'. A la base du formalisme STU se trouve la supposition que l'echelle de la nouvelle physique, M, est beaucoup plus grande que q, l'echelle a laquelle on effectue des mesures. Il en resulte que les effets obliques se parametrisent par les trois variables S, T et U. Par contre, dans le formalisme STUVWX, nous avons admis la possibilite que M~ q. Dans "A Global Fit to Extended Oblique Parameters", nous avons effectue deux fits statistiques sur un ensemble de mesures electrofaibles de haute precision. Dans le premier fit, nous avons pose V=W=X=0, obtenant ainsi des contraintes pour l'ensemble {S,T,U}. Dans le second fit, nous avons inclus tous les six parametres.

Morphological Effects in Auditory Word Recognition: Evidence from Danish

ERIC Educational Resources Information Center

Balling, Laura Winther; Baayen, R. Harald

2008-01-01

In this study, we investigate the processing of morphologically complex words in Danish using auditory lexical decision. We document a second critical point in auditory comprehension in addition to the Uniqueness Point (UP), namely the point at which competing morphological continuation forms of the base cease to be compatible with the input,…

Minding Morphology: How Morphological Awareness Relates to Reading for English Language Learners

ERIC Educational Resources Information Center

Goodwin, Amanda P.; Huggins, A. Corinne; Carlo, Maria S.; August, Diane; Calderon, Margarita

2013-01-01

This study explored subprocesses of reading for 157 fifth grade Spanish-speaking English language learners (ELLs) by examining whether morphological awareness made a unique contribution to reading comprehension beyond a strong covariate-phonological decoding. The role of word reading and reading vocabulary as mediators of this relationship was…

Tool making, hand morphology and fossil hominins.

PubMed

Marzke, Mary W

2013-11-19

Was stone tool making a factor in the evolution of human hand morphology? Is it possible to find evidence in fossil hominin hands for this capability? These questions are being addressed with increasingly sophisticated studies that are testing two hypotheses; (i) that humans have unique patterns of grip and hand movement capabilities compatible with effective stone tool making and use of the tools and, if this is the case, (ii) that there exist unique patterns of morphology in human hands that are consistent with these capabilities. Comparative analyses of human stone tool behaviours and chimpanzee feeding behaviours have revealed a distinctive set of forceful pinch grips by humans that are effective in the control of stones by one hand during manufacture and use of the tools. Comparative dissections, kinematic analyses and biomechanical studies indicate that humans do have a unique pattern of muscle architecture and joint surface form and functions consistent with the derived capabilities. A major remaining challenge is to identify skeletal features that reflect the full morphological pattern, and therefore may serve as clues to fossil hominin manipulative capabilities. Hominin fossils are evaluated for evidence of patterns of derived human grip and stress-accommodation features.

Tool making, hand morphology and fossil hominins

PubMed Central

Marzke, Mary W.

2013-01-01

Was stone tool making a factor in the evolution of human hand morphology? Is it possible to find evidence in fossil hominin hands for this capability? These questions are being addressed with increasingly sophisticated studies that are testing two hypotheses; (i) that humans have unique patterns of grip and hand movement capabilities compatible with effective stone tool making and use of the tools and, if this is the case, (ii) that there exist unique patterns of morphology in human hands that are consistent with these capabilities. Comparative analyses of human stone tool behaviours and chimpanzee feeding behaviours have revealed a distinctive set of forceful pinch grips by humans that are effective in the control of stones by one hand during manufacture and use of the tools. Comparative dissections, kinematic analyses and biomechanical studies indicate that humans do have a unique pattern of muscle architecture and joint surface form and functions consistent with the derived capabilities. A major remaining challenge is to identify skeletal features that reflect the full morphological pattern, and therefore may serve as clues to fossil hominin manipulative capabilities. Hominin fossils are evaluated for evidence of patterns of derived human grip and stress-accommodation features. PMID:24101624

Analysis of electrical property changes of skin by oil-in-water emulsion components

PubMed Central

Jeong, CB; Han, JY; Cho, JC; Suh, KD; Nam, GW

2013-01-01

Synopsis ObjectivesAs the ‘Dry Skin Cycle’ produces continuous deterioration, cosmetic xerosis (flaky, dry skin) is one of the major concerns to most consumers. The purpose of this study was to investigate the moisturizing effect of oil-in-water (O/W) emulsion components. There are numerous types of oils, waxes, polyols and surfactants used as ingredients in skincare products. However, the moisturizing effect of each ingredient and understanding each use to make an effective moisturizing products are still not well understood. Methods To provide answers to these questions, we investigated the moisturizing effect of widely used 41 components (four different classes) in a simple O/W emulsion using capacitance methods. 106 different single oils, and combinations of oil with oil, wax, humectants, and surfactant were formulated and tested. Results In this study, we found that most of the O/W emulsion components had hydration effects on the skin. (i) The average relative water content increase (RWCI) rate of a single oil-based emulsion was 11.8 ± 5.2% (SE) and 7.9 ± 6.0% (SE) at 3 and 6 h, respectively. (ii) An oil combination emulsion showed an average RWCI rate similar to that of a single oil-based emulsion, 12.6 ± 6.0% (SE) and 12.1 ± 6.4% (SE) at 3 and 6 h, respectively (iii) A combination of waxes with oil showed an average RWCI rate of 16 ± 5.6% (SE) and 12.4 ± 4.5% (SE) at 3 and 6 h, respectively. (iv) Humectant combinations showed the highest average RWCI rate 28 ± 7.3% (SE) and 22.2 ± 7.5% (SE) at 3 and 6 h, respectively (v) Surfactant combinations had an average RWCI of 10.8 ± 4.5% (SE) and 6.0 ± 4.0% (SE) at 3 and 6 h, respectively. Conclusion Interestingly, it was difficult to find moisturizing power differences among samples in the same group. Only the humectants group showed significant differences among samples. Glycerine and urea showed significant skin hydration effects compared with other humectants. We also found a significant moisturizing effect by analysing the chemical functional groups; amide class had a higher hydration effect than betaines and disaccharides in humectants combination. Résumé Objectif Puisque le «cycle de la peau sèche” produit une détérioration continue, la xérose cosmétique (squameuse, peau sèche) est l’une des préoccupations majeures pour la plupart des consommateurs. Le but de cette étude était d’étudier l’effet hydratant des composants d’émulsions H / E. Il existe de nombreux types d’huiles, des cires, de polyols, et des tensioactifs utilisés comme ingrédients dans les produits de soins de la peau. Cependant, l’effet hydratant de chaque ingrédient et de leur utilisation dans des produits hydratants efficaces ne sont pas encore bien compris. MethodesPour apporter des réponses à ces questions, nous avons étudié l’effet hydratant des 41 éléments (4 classes différentes) largement utilisés dans une émulsion simple O/W en utilisant des méthodes de capacitance. 106 huiles individuelles différentes et des combinaisons d’huile avec de l’huile, de la cire, des humectants, et de tensioactifs ont été formulées et testées. ResultatsDans cette étude, nous avons constaté que la plupart des composants des émulsions huile-dans-eau (H/E) possédaient des effets d’hydratation de la peau. (i) Le taux moyen d’augmentation d’eau (RWCI = relative water content increase) d’une émulsion à base d’une seule huile était de 11,8 ± 5,2% (SE) et de 7,9 ± 6,0% (SE) à 3 et 6 h, respectivement. (ii) Une émulsion de combinaison d’huile montrait une RWCI similaire à celle d’une émulsion à base d’huile unique, 12,6 ± 6,0% (SE) et 12,1 ± 6,4% (SE) à 3 et 6 h, respectivement. (iii) Une combinaison des cires avec de l’huile présentait une RWCI de 16 ± 5,6% (SE) et 12,4 ± 4,5% (SE) à 3 et 6 h, respectivement. (iv) Les combinaisons d’humectant ont montré la plus forte augmentation avec +28 ± 7,3% (SE) et 22,2 ± 7,5% (SE) à 3 et 6 h, respectivement. (v) Les combinaisons de tensioactifs ont une RWCI moyenne de 10,8 ± 4,5% (SE) et de 6,0 ± 4,0% (SE) à 3 et 6 h, respectivement. ConclusionFait intéressant, il était difficile de trouver des différences de pouvoir d’hydratation entre les échantillons dans le même groupe. Seul le groupe des humectants a montré des différences significatives entre les échantillons. La glycérine et l’urée ont montré des effets significatifs sur l’hydratation de la peau par rapport aux autres humectants. Nous avons également constaté un effet hydratant important en analysant les groupes fonctionnels chimiques; la classe “amide” a eu un effet d’hydratation plus élevé que les bétaînes et disaccharides dans les combinaisons des humectants. PMID:23621673

The Role of Morphological Awareness in Word Reading Skills in Japanese: A Within-Language Cross-Orthographic Perspective

ERIC Educational Resources Information Center

Muroya, Naoko; Inoue, Tomohiro; Hosokawa, Miyuki; Georgiou, George K.; Maekawa, Hisao; Parrila, Rauno

2017-01-01

We examined the relationship between morphological awareness and word reading skills in syllabic Hiragana and morphographic Kanji. Participants were 127 Grade 1 Japanese-speaking children who were followed until Grade 2. The results showed that Grade 1 morphological awareness was uniquely and comparably associated with word reading skills in both…

Roles of Morphological Awareness in the Reading Comprehension of Spanish-Speaking Language Minority Learners: Exploring Partial Mediation by Vocabulary and Reading Fluency

ERIC Educational Resources Information Center

Kieffer, Michael J.; Biancarosa, Gina; Mancilla-Martinez, Jeannette

2013-01-01

This study investigated the direct and indirect roles of morphological awareness reading comprehension for Spanish-speaking language minority learners reading in English. Multivariate path analysis was used to investigate the unique contribution of derivational morphological awareness to reading comprehension as well as its indirect contributions…

Systemes Fermioniques a Basse Dimension D'espace: Supraconductivite, Effet Hall Quantique et Statistique Fractionnaire

NASA Astrophysics Data System (ADS)

Sakhi, Said

Cette these est constituee de trois sujets de recherche distincts. Les deux premiers articles traitent du phenomene de supraconductivite dans un modele bidimensionnel, dans le troisieme article on etudie l'action effective d'un systeme electronique soumis a l'effet d'un champ magnetique (systeme de Hall) et le dernier article examine la quantification d'un systeme de particules identiques en deux dimensions d'espace et la possibilite des anyons. Le modele qu'on analyse dans les deux premiers articles est un systeme fermionique dont les particules chargees et de masse nulle interagissent entre elles avcc un couplage attractif et fort. L'analyse de l'action effective decrivant la physique a basse energie nous permet d'examiner la structure de l'espace de phase. A temperature nulle, le parametre d'ordre du systeme prend une valeur moyenne non nulle. Consequemment, la symetrie continue U(1) du modele est spontanement brisee et il en resulte l'apparition d'un mode de Goldstone. En presence d'un champ electromagnetique externe, ce mode disparait et le champ de jauge acquiert une masse donc l'effet Meissner caracteristique d'un supraconducteur. Bien que le modele ne soit pas renormalisable dans le sens perturbatif, on montre qu'il l'est dans le cadre du developpement en 1/N ou N est le nombre d'especes fermioniques. En outre, on montre que l'inclusion des effets thermiques change radicalement le mecanisme de supraconductivite. En effet, on montre que la brisure spontanee de la symetrie U(1) n'est plus possible a temperature finie a cause de tres severes divergences infrarouges. Par contre, la dynamique des tourbillons (vortex) existant dans le plan devient essentielle. On montre que le phenomene de supraconductivite resulte du confinement de ces objets topologiques et que la temperature critique s'identifie a celle de Kosterlitz -Thouless. Ce mecanisme de supraconductivite presente l'avantage d'aboutir a un rapport gap a la temperature critique plus eleve que celui du modele de BCS et la non violation de la symetrie par renversement du temps et de l'espace contrairement au modele anyonique. Dans le troisieme article, on a developpe une methode systematique pour calculer les determinants fermioniques en presence d'un champ magnetique perpendiculaire au plan de confinement des particules. Aussi bien les effets thermiques que ceux dus aux impuretes sont pris en consideration dans cette methode. La technique est illustree dans le cas du systeme de Hall quantique. Finalement, dans le dernier article, on discute la quantification d'un systeme de particules identiques dans le plan. Apres avoir correctement defini l'espace de phase classique du systeme, l'analyse fait ressortir deux parametres fondamentaux denotes par theta et alpha. Le premier parametre theta est associe a l'intensite du flux magnetique localise au vertex du cone et definit la statistique des particules. Pour des valeurs arbitraires de theta on parle d'anyons. L'autre parametre alpha est associe a l'extension auto-adjointe de l'hamiltonien et ressort de l'unitarite de la theorie. On montre par un exemple explicite que alpha peut etre vu comme le vestige d'une interaction a tres courte distance (haute energie) entre les particules du systeme. Finalement, on montre que le groupe de symetrie du systeme avec extension auto -adjointe n'est plus SO(2,1) car le generateur de dilatation de ce groupe n'est plus compatible avec un parametre alpha arbitraire. (Abstract shortened by UMI.).

L'effet Hall Quantique

NASA Astrophysics Data System (ADS)

Samson, Thomas

Nous proposons une methode permettant d'obtenir une expression pour la conductivite de Hall de structures electroniques bidimensionnelles et nous examinons celle -ci a la limite d'une temperature nulle dans le but de verifier l'effet Hall quantique. Nous allons nous interesser essentiellement a l'effet Hall quantique entier et aux effets fractionnaires inferieurs a un. Le systeme considere est forme d'un gaz d'electrons en interaction faible avec les impuretes de l'echantillon. Le modele du gaz d'electrons consiste en un gaz bidimensionnel d'electrons sans spin expose perpendiculairement a un champ magnetique uniforme. Ce dernier est decrit par le potentiel vecteur vec{rm A} defini dans la jauge de Dingle ou jauge symetrique. Conformement au formalisme de la seconde quantification, l'hamiltonien de ce gaz est represente dans la base des etats a un-corps de Dingle |n,m> et exprime ainsi en terme des operateurs de creation et d'annihilation correspondants a_sp{ rm n m}{dag} et a _{rm n m}. Nous supposons de plus que les electrons du niveau fondamental de Dingle interagissent entre eux via le potentiel coulombien. La methode utilisee fait appel a une equation mai tresse a N-corps, de nature quantique et statistique, et verifiant le second principe de la thermodynamique. A partir de celle-ci, nous obtenons un systeme d'equations differentielles appele hierarchie d'equations quantique dont la resolution nous permet de determiner une equation a un-corps, dite de Boltzmann quantique, et dictant l'evolution de la moyenne statistique de l'operateur non-diagonal a _sp{rm n m}{dag } a_{rm n}, _{rm m}, sous l'action du champ electrique applique vec{rm E}(t). C'est sa solution Tr(p(t) a _sp{rm n m}{dag} a_{rm n},_ {rm m}), qui definit la relation de convolution entre la densite courant de Hall vec{rm J}_{rm H }(t) et le champ electrique vec {rm E}(t) dont la transformee de Laplace-Fourier du noyau nous fournit l'expression de la conductivite de Hall desiree. Pour une valeur de facteur d'occupation (nombre d'electrons/degenerescence des etats de Dingle) superieure a un, c'est-a-dire en absence d'interaction electron-electron, il nous sera facile d'evaluer cette conductivite a la limite d'une temperature nulle et de demontrer qu'elle tend vers l'une des valeurs quantiques qe^2/h conformement a l'effet Hall quantique entier. Cependant, pour une valeur du facteur d'occupation inferieure a un, c'est-a-dire en presence d'interaction electron-electron, nous ne pourrons evaluer cette limite et obtenir les resultats escomptes a cause de l'impossibilite de determiner l'un des termes impliques. Neanmoins, ce dernier etant de nature statistique, il pourra etre aisement mis en fonction du propagateur du gaz d'electrons dont on doit maintenant determiner une expression en regime effet Hall quantique fractionnaire. Apres avoir demontre l'impuissance de la theorie des perturbations, basee sur le theoreme de Wick et la technique des diagrammes de Feynman, a accomplir cette tache correctement, nous proposons une seconde methode. Celle -ci fait appel au formalisme de l'integrale fonctionnelle et a l'utilisation d'une transformation de Hubbard-Stratonovich generalisee permettant de substituer a l'interaction a deux-corps une interaction effective a un-corps. L'expression finale obtenue bien que non completement resolue, devrait pouvoir etre estimee par une bonne approximation analytique ou au pire numeriquement.

Three-dimensional analysis of the uniqueness of the anterior dentition in orthodontically treated patients and twins.

PubMed

Franco, A; Willems, G; Souza, P H C; Tanaka, O M; Coucke, W; Thevissen, P

2017-04-01

Dental uniqueness can be proven if no perfect match in pair-wise morphological comparisons of human dentitions is detected. Establishing these comparisons in a worldwide random population is practically unfeasible due to the need for a large and representative sample size. Sample stratification is an option to reduce sample size. The present study investigated the uniqueness of the human dentition in randomly selected subjects (Group 1), orthodontically treated patients (Group 2), twins (Group 3), and orthodontically treated twins (Group 4) in comparison with a threshold control sample of identical dentitions (Group 5). The samples consisted of digital cast files (DCF) obtained through extraoral 3D scanning. A total of 2.013 pair-wise morphological comparisons were performed (Group 1 n=110, Group 2 n=1.711, Group 3 n=172, Group 4 n=10, Group 5 n=10) with Geomagic Studio ® (3D Systems ® , Rock Hill, SC, USA) software package. Comparisons within groups were performed quantifying the morphological differences between DCF in Euclidean distances. Comparisons between groups were established applying One-way ANOVA. To ensure fair comparisons a post-hoc Power Analysis was performed. ROC analysis was applied to distinguish unique from non-unique dentures. Identical DCF were not detected within the experimental groups (from 1 to 4). The most similar DCF had Euclidian distance of 5.19mm in Group 1, 2.06mm in Group 2, 2.03mm in Group 3, and 1.88mm in Group 4. Groups 2 and 3 were statistically different from Group 5 (p<0.05). Statistically significant difference between Group 4 and 5 revealed to be possible including more pair-wise comparisons in both groups. The ROC analysis revealed sensitivity rate of 80% and specificity between 66.7% and 81.6%. Evidence to sustain the uniqueness of the human dentition in random and stratified populations was observed in the present study. Further studies testing the influence of the quantity of tooth material on morphological difference between dentitions and its impact on uniqueness remain necessary. Copyright © 2017 Elsevier B.V. All rights reserved.

L’effet du yoga chez les patients atteints de cancer

PubMed Central

Côté, Andréanne; Daneault, Serge

2012-01-01

Résumé Objectif Déterminer si le yoga thérapeutique améliore la qualité de vie de patients atteints de cancer. Sources des données Recherche effectuée avec la base de données MEDLINE (1950–2010) en utilisant les mots-clés yoga, cancer et quality of life. Sélection des études Priorité accordée aux études cliniques randomisées contrôlées évaluant l’effet du yoga sur différents symptômes susceptibles de se présenter chez des patients atteints de cancer en Amérique du Nord. Synthèse Quatre études cliniques randomisées contrôlées ont d’abord été analysées, puis 2 études sans groupe-contrôle. Trois études réalisées en Inde et au Proche-Orient ont également apporté des éléments intéressants au plan méthodologique. Les interventions proposées comprenaient des séances de yoga d’une durée et d’une fréquence variables. Les paramètres mesurés variaient également d’une étude à l’autre. Plusieurs symptômes ont connu des améliorations significatives avec le yoga (meilleure qualité du sommeil, diminution des symptômes anxieux ou dépressifs, amélioration du bien-être spirituel, etc.). Il a aussi semblé que la qualité de vie, dans sa globalité ou dans certaines de ses composantes spécifiques, s’améliorait. Conclusion La variété des effets bénéfiques produits, l’absence d’effet secondaire et le rapport coût-bénéfice avantageux du yoga thérapeutique en fait une intervention intéressante à suggérer par les médecins de famille aux patients atteints de cancer. Certaines lacunes méthodologiques ont pu diminuer la puissance statistique des études présentées, à commencer par la taille restreinte des échantillons et par l’assiduité variable des patients soumis à l’intervention. Il est également possible que les échelles de mesure utilisées ne convenaient pas à ce type de situation et de clientèle pour qu’en soit dégagé un effet significatif. Toutefois, les commentaires favorables des participants recueillis au cours des études et leur degré d’appréciation et de bien-être donnent à penser qu’il faille poursuivre les recherches pour mieux en comprendre les mécanismes.

On the Relationship between Phonological Awareness, Morphological Awareness and Chinese Literacy Skills: Evidence from an 8-Year Longitudinal Study

ERIC Educational Resources Information Center

Pan, Jinger; Song, Shuang; Su, Mengmeng; McBride, Catherine; Liu, Hongyun; Zhang, Yuping; Li, Hong; Shu, Hua

2016-01-01

The present study reported data on phonological awareness, morphological awareness, and Chinese literacy skills of 294 children from an 8-year longitudinal study. Results showed that mainland Chinese children's preliterate syllable awareness at ages 4 to 6 years uniquely predicted post-literate morphological awareness at ages 7 to 10 years.…

Le rôle médiateur du fonctionnement familial dans la relation entre l’adversité familiale et l’adaptation sociale des enfants d’âge préscolaire1

PubMed Central

Felli, M. C.; Parent, S.; Zelazo, P. D.; Tremblay, R. E.; Séguin, J. R.

2017-01-01

Résumé À la petite enfance, l’adaptation sociale de l’enfant dépend en partie des risques auxquels il est exposé dans son environnement. Toutefois, les mécanismes par lesquels les facteurs de risque opèrent leurs influences sur l’adaptation sociale de l’enfant sont peu documentés. Ainsi, cette étude examine dans un premier temps l’effet principal de l’adversité familiale, un cumul de facteurs de risque, sur les problèmes de comportement intériorisés et extériorisés, ainsi que sur la sécurité d’attachement des enfants d’âge préscolaire. Dans un deuxième temps, elle évalue le rôle médiateur du fonctionnement familial dans le lien entre l’adversité familiale et les problèmes de comportement de même qu’entre l’adversité familiale et la sécurité d’attachement des enfants d’âge préscolaire. Les 572 participants à l’étude (n=572) sont âgés entre cinq et 42 mois lors des mesures de l’adversité familiale et de 42 mois lors de la mesure des problèmes de comportement et du fonctionnement familial. Quatre-vingt d’entre eux (n=80) ont fait l’objet d’une mesure de sécurité d’attachement à 48 mois. Les résultats indiquent, d’abord, un effet principal de l’adversité familiale sur les problèmes de comportement intériorisés et extériorisés. Un effet médiateur significatif du fonctionnement familial est ensuite rapporté dans le lien entre l’adversité familiale et les problèmes de comportement intériorisés et extériorisés. Aucun effet significatif n’est observé pour la sécurité d’attachement des enfants de 48 mois. PMID:28567062

A morphological comparison of narrow, low-gradient streams traversing wetland environments to alluvial streams.

PubMed

Jurmu, Michael C

2002-12-01

Twelve morphological features from research on alluvial streams are compared in four narrow, low-gradient wetland streams located in different geographic regions (Connecticut, Indiana, and Wisconsin, USA). All four reaches differed in morphological characteristics in five of the features compared (consistent bend width, bend cross-sectional shape, riffle width compared to pool width, greatest width directly downstream of riffles, and thalweg location), while three reaches differed in two comparisons (mean radius of curvature to width ratio and axial wavelength to width ratio). The remaining five features compared had at least one reach where different characteristics existed. This indicates the possibility of varying morphology for streams traversing wetland areas further supporting the concept that the unique qualities of wetland environments might also influence the controls on fluvial dynamics and the development of streams. If certain morphological features found in streams traversing wetland areas differ from current fluvial principles, then these varying features should be incorporated into future wetland stream design and creation projects. The results warrant further research on other streams traversing wetlands to determine if streams in these environments contain unique morphology and further investigation of the impact of low-energy fluvial processes on morphological development. Possible explanations for the morphology deviations in the study streams and some suggestions for stream design in wetland areas based upon the results and field observations are also presented.

Internal stresses, dislocation mobility and ductility

NASA Astrophysics Data System (ADS)

Saada, G.

1991-06-01

The description of plastic deformation must take into account individual mechanisms and heterogeneity of plastic strain. Influence of dislocation interaction with forest dislocations and of cross slip are connected with the organization of dipole walls. The latter are described and their development is explained as a consequence of edge effects. Applications are discussed. La description de la déformation plastique doit prendre en compte les interactions individuelles des dislocations et l'hétérogénéité à grande échelle de la déformation plastique. Les interactions des dislocations mobiles avec la forêt de dislocations, le glissement dévié, ont pour effet la création de parois dipolaires. Celles-ci sont décrites et leur développement est appliqué à partir des effets de bord.

Effets de l'humidite sur la propagation du delaminage dans un composite carbone/epoxy sollicite en mode mixte I/II

NASA Astrophysics Data System (ADS)

LeBlanc, Luc R.

Les materiaux composites sont de plus en plus utilises dans des domaines tels que l'aerospatiale, les voitures a hautes performances et les equipements sportifs, pour en nommer quelques-uns. Des etudes ont demontre qu'une exposition a l'humidite nuit a la resistance des composites en favorisant l'initiation et la propagation du delaminage. De ces etudes, tres peu traitent de l'effet de l'humidite sur l'initiation du delaminage en mode mixte I/II et aucune ne traite des effets de l'humidite sur le taux de propagation du delaminage en mode mixte I/II dans un composite. La premiere partie de cette these consiste a determiner les effets de l'humidite sur la propagation du delaminage lors d'une sollicitation en mode mixte I/II. Des eprouvettes d'un composite unidirectionnel de carbone/epoxy (G40-800/5276-1) ont ete immergees dans un bain d'eau distillee a 70°C jusqu'a leur saturation. Des essais experimentaux quasi-statiques avec des chargements d'une gamme de mixites des modes I/II (0%, 25%, 50%, 75% et 100%) ont ete executes pour determiner les effets de l'humidite sur la resistance au delaminage du composite. Des essais de fatigue ont ete realises, avec la meme gamme de mixite des modes I/II, pour determiner 1'effet de 1'humidite sur l'initiation et sur le taux de propagation du delaminage. Les resultats des essais en chargement quasi-statique ont demontre que l'humidite reduit la resistance au delaminage d'un composite carbone/epoxy pour toute la gamme des mixites des modes I/II, sauf pour le mode I ou la resistance au delaminage augmente apres une exposition a l'humidite. Pour les chargements en fatigue, l'humidite a pour effet d'accelerer l'initiation du delaminage et d'augmenter le taux de propagation pour toutes les mixites des modes I/II. Les donnees experimentales recueillies ont ete utilisees pour determiner lesquels des criteres de delaminage en statique et des modeles de taux de propagation du delaminage en fatigue en mode mixte I/II proposes dans la litterature representent le mieux le delaminage du composite etudie. Une courbe de regression a ete utilisee pour determiner le meilleur ajustement entre les donnees experimentales et les criteres de delaminage en statique etudies. Une surface de regression a ete utilisee pour determiner le meilleur ajustement entre les donnees experimentales et les modeles de taux de propagation en fatigue etudies. D'apres les ajustements, le meilleur critere de delaminage en statique est le critere B-K et le meilleur modele de propagation en fatigue est le modele de Kenane-Benzeggagh. Afin de predire le delaminage lors de la conception de pieces complexes, des modeles numeriques peuvent etre utilises. La prediction de la longueur de delaminage lors des chargements en fatigue d'une piece est tres importante pour assurer qu'une fissure interlaminaire ne va pas croitre excessivement et causer la rupture de cette piece avant la fin de sa duree de vie de conception. Selon la tendance recente, ces modeles sont souvent bases sur l'approche de zone cohesive avec une formulation par elements finis. Au cours des travaux presentes dans cette these, le modele de progression du delaminage en fatigue de Landry & LaPlante (2012) a ete ameliore en y ajoutant le traitement des chargements en mode mixte I/II et en y modifiant l'algorithme du calcul de la force d'entrainement maximale du delaminage. Une calibration des parametres de zone cohesive a ete faite a partir des essais quasi-statiques experimentaux en mode I et II. Des resultats de simulations numeriques des essais quasi-statiques en mode mixte I/II, avec des eprouvettes seches et humides, ont ete compares avec les essais experimentaux. Des simulations numeriques en fatigue ont aussi ete faites et comparees avec les resultats experimentaux du taux de propagation du delaminage. Les resultats numeriques des essais quasi-statiques et de fatigue ont montre une bonne correlation avec les resultats experimentaux pour toute la gamme des mixites des modes I/II etudiee.

Nanoporous TiO2 nanoparticle assemblies with mesoscale morphologies: nano-cabbage versus sea-anemone

NASA Astrophysics Data System (ADS)

Darbandi, Masih; Gebre, Tesfaye; Mitchell, Lucas; Erwin, William; Bardhan, Rizia; Levan, M. Douglas; Mochena, Mogus D.; Dickerson, James H.

2014-05-01

We report the novel synthesis of nanoporous TiO2 nanoparticle ensembles with unique mesoscale morphologies. Constituent nanoparticles evolved into multifaceted assemblies, exhibiting excellent crystallinity and enhanced photocatalytic activity compared with commercial TiO2. Such materials could be exploited for applications, like organic pollutant degradation.We report the novel synthesis of nanoporous TiO2 nanoparticle ensembles with unique mesoscale morphologies. Constituent nanoparticles evolved into multifaceted assemblies, exhibiting excellent crystallinity and enhanced photocatalytic activity compared with commercial TiO2. Such materials could be exploited for applications, like organic pollutant degradation. Electronic supplementary information (ESI) available: Synthesis and characterization procedures, TEM/XRD of samples prepared at different temperature and water content, table of nitrogen adsorption-desorption values of different samples. See DOI: 10.1039/c3nr06154j

Inhomogeneous magnesium hydride synthesized by low temperature ion implantation: weak localization effect

NASA Astrophysics Data System (ADS)

Nédellec, P.; Dumoulin, L.; Burger, J. P.; Bernas, H.; Köstler, H.; Traverse, A.

1993-11-01

Metastable MgHx hydride was prepared by H ion implantation into Mg films at 5 K. The resistivity and magnetoresistance temperature dependence reveal weak localization effects due to atomic disorder. At low hydrogen concentrations, x le 0.3, the conductivity varies as σ sim log(T), typical of two-dimensional weak localization behaviour. The resistivity is also very sensitive to the sample inhomogeneity, due to H diffusion, which can be modelled by introducing a temperature-dependent geometrical percolating factor G. At higher H concentrations, 0.7 le x le 3, after annealing at 20 K, 50 K and 110 K, the samples also exhibit weak localization but with three-dimensional behaviour i.e. a σ sim sqrt{T}. Our analysis is consistent with the existence of an inhomogeneous system formed by a mixture of two phases with contrasted conduction properties, one of which is a well-behaved metal, while the other displays the localization properties. The results lead us to identify the former phase to a non percolating superconducting phase at low temperature. Des films d'hydrure MgHx sont préparés, hors de l'équilibre thermodynamique, par implantation d'ions H dans des films de Mg maintenus à 5 K. La mesure de la résistance et de la magnétorésistance en fonction de la température met en évidence des effets importants de localisation électronique due au désordre atomique. Pour les faibles concentrations d'hydrogène, x le 0,3, la conductivité varie comme σ sim log(T), variation caractéristique d'un comportement dominé par les effets de localisation électronique faible à 2 dimensions. La résistivité est très sensible aux effets d'inhomogénéité, liés à la diffusion de H. Nous avons modélisé ces effets en introduisant un coefficient géométrique variant avec la température. Pour les concentrations plus élevées (0, 7 le x le 3), après un recuit à 20 K, 50 K et 110 K, les films montrent également des effets de localisation mais la conductivité varie maintenant comme σ sim sqrt{T}, caractéristique d'un comportement tridimensionnel. L'analyse des résultats est compatible avec l'hypothèse d'un système inhomogène formé du mélange de deux phases avec des propriétés électriques contrastées : un “mauvais métal" et un “bon métal" qui, à basse température, pourrait présenter un état supraconducteur non percolant.

Des recommandations probantes pour surveiller l’innocuité des antipsychotiques de deuxième génération chez les enfants et les adolescents

PubMed Central

Pringsheim, Tamara; Panagiotopoulos, Constadina; Davidson, Jana; Ho, Josephine

2012-01-01

HISTORIQUE : Au Canada, l’utilisation d’antipsychotiques, notamment les antipsychotiques de deuxième génération (ADG), a augmenté de façon considérable depuis cinq ans chez les enfants ayant des troubles de santé mentale. Ces médicaments ont le potentiel de causer de graves complications métaboliques et neurologiques lorsqu’on les utilise de manière chronique. OBJECTIF : Synthétiser les données probantes relatives aux effets secondaires métaboliques et neurologiques précis associés à l’usage d’ADG chez les enfants et fournir des recommandations probantes sur la surveillance de ces effets secondaires. MÉTHODOLOGIE : Les auteurs ont procédé à une analyse systématique des essais cliniques contrôlés des ADG auprès d’enfants. Ils ont fait des recommandations à l’égard de la surveillance de l’innocuité des ADG d’après un modèle de classification fondé sur le système GRADE (système de notation de l’évaluation et de l’élaboration des recommandations). Lorsque les données probantes n’étaient pas suffisantes, ils fondaient leurs recommandations sur le consensus et l’avis d’experts. Un groupe consensuel multidisciplinaire a analysé toutes les données probantes pertinentes et est parvenu à un consensus à l’égard des recommandations. RÉSULTATS : Les recommandations probantes portant sur la surveillance de l’innocuité des ADG figurent dans les présentes lignes directrices. Les auteurs indiquent la qualité des recommandations relatives à des examens physiques et tests de laboratoire précis à l’égard de chaque ADG à des moments déterminés. CONCLUSION : De multiples essais aléatoires et contrôlés ont permis d’évaluer l’efficacité de bon nombre des ADG utilisés pour traiter les troubles de santé mentale en pédiatrie. Toutefois, leurs avantages ne sont pas sans risques : on observe à la fois des effets secondaires métaboliques et neurologiques chez les enfants traités au moyen d’ADG. Le risque de prise de poids, d’augmentation de l’indice de masse corporelle et de taux lipidiques anormaux est plus élevé à l’utilisation d’olanzapine, suivie de la clozapine et de la quétiapine. Quant au risque d’effets secondaires neurologiques des traitements, il est plus élevé à l’utilisation de rispéridone, d’olanzapine et d’aripiprazole. Des interventions de surveillance pertinentes des effets secondaires amélioreront la qualité des soins des enfants traités à l’aide de ces médicaments. PMID:24082813

Etude des melanges co-continus d'acide polylactique et d'amidon thermoplastique (PLA/TPS)

NASA Astrophysics Data System (ADS)

Chavez Garcia, Maria Graciela

Les melanges co-continus sont des melanges polymeriques ou chaque composant se trouve dans une phase continue. Pour cette raison, les caracteristiques de chacun des composants se combinent et il en resulte un materiau avec une morphologie et des proprietes particulieres. L'acide polylactique (PLA) et l'amidon thermoplastique (TPS) sont des biopolymeres qui proviennent de ressources renouvelables et qui sont biodegradables. Dans ce projet, differents melanges de PLA et TPS a une haute concentration de TPS ont ete prepares dans une extrudeuse bi-vis afin de generer des structures co-continues. Grace a la technique de lixiviation selective, le TPS est enleve pour creer une structure poreuse de PLA qui a pu etre analysee au moyen de la microtomographie R-X et de la microscopie electronique a balayage MEB. L'analyse des images 2D et 3D confirme la presence de la structure co-continue dans les melanges dont la concentration en TPS. se situe entre 66% et 80%. L'effet de deux plastifiants, le glycerol seul et le melange de glycerol et de sorbitol, dans la formulation de TPS est etudie dans ce travail. De plus, nous avons evalue l'effet du PLA greffe a l'anhydride maleique (PLAg) en tant que compatibilisant. On a trouve que la phase de TPS obtenue avec le glycerol est plus grande. L'effet de recuit sur la taille de phases est aussi analyse. Grace aux memes techniques d'analyse, on a etudie l'effet du procede de moulage par injection sur la morphologie. On a constate que les pieces injectees presentent une microstructure heterogene et differente entre la surface et le centre de la piece. Pres de la surface, une peau plus riche en PLA est presente et les phases de TPS y sont allongees sous forme de lamelles. Plus au centre de la piece, une morphologie plus cellulaire est observee pour chaque phase continue. L'effet des formulations sur les proprietes mecaniques a aussi ete etudie. Les pieces injectees dont la concentration de TPS est plus grande presentent une moindre resistance a la traction. La presence du compatibilisant dans la region co-continue affecte negativement cette resistance. En considerant que l'amidon est un biomateriau abondant, moins cher et plus rapidement biodegradable, son ajout dans le PLA presente l'avantage de reduire le cout tout en augmentant la vitesse de degradation du PLA. De plus, une structure continue poreuse de PLA produit par la technique de lixiviation selective a des applications potentielles soit comme materiau a degradation rapide ou encore, une fois la phase TPS retiree, comme substrat a porosite ouverte pour la fabrication de membranes, de supports cellulaires ou de filtres. Mots-cles : melanges immiscibles, acide polylactique, amidon thermoplastique, morphologie cocontinue, lixiviation selective, microtomographie R-X, materiau rigide poreux biodegradable.

Chromophobe hepatocellular carcinoma with abrupt anaplasia: a proposal for a new subtype of hepatocellular carcinoma with unique morphological and molecular features

PubMed Central

Wood, Laura D; Heaphy, Christopher M; Daniel, Hubert Darius-J; Naini, Bita V; Lassman, Charles R; Arroyo, May R; Kamel, Ihab R; Cosgrove, David P; Boitnott, John K; Meeker, Alan K; Torbenson, Michael S

2014-01-01

Hepatocellular carcinomas exhibit heterogeneous morphologies by routine light microscopy. Although some morphologies represent insignificant variations in growth patterns, others may represent unrecognized subtypes of hepatocellular carcinoma. Identification of these subtypes could lead to separation of hepatocellular carcinomas into discrete groups with unique underlying genetic changes, prognosis, or therapeutic responses. In order to identify potential subtypes, two pathologists independently screened a cohort of 219 unselected hepatocellular carcinoma resection specimens and divided cases into potential subtypes. One of these promising candidate subtypes was further evaluated using histological and molecular techniques. This subtype was characterized by a unique and consistent set of histological features: smooth chromophobic cytoplasm, abrupt focal nuclear anaplasia (small clusters of tumor cells with marked nuclear anaplasia in a background of tumor cells with bland nuclear cytology), and scattered microscopic pseudocysts—we designate this variant as ‘chromophobe hepatocellular carcinoma with abrupt anaplasia’. Thirteen cases were identified (6% of all hepatocellular carcinomas), including 6 men and 7 women with an average age of 61 years. Six cases occurred in cirrhotic livers. Serum AFP was elevated in 6 out of 10 cases. There were a variety of underlying liver diseases, but cases were enrichment for chronic hepatitis B, P = 0.006. Interestingly, at the molecular level, this variant was strongly associated with the alternative lengthening of telomere (ALT) phenotype by telomere FISH. ALT is a telomerase-independent mechanism of telomere maintenance and is found in approximately 8% of unselected hepatocellular carcinomas. In contrast, 11/12 (92%) of the cases of chromophobe hepatocellular carcinoma with abrupt anaplasia were ALT-positive. In summary, we propose that chromophobe hepatocellular carcinoma with abrupt anaplasia represents a new subtype of hepatocellular carcinoma with unique morphological and molecular features. PMID:23640129

Chromophobe hepatocellular carcinoma with abrupt anaplasia: a proposal for a new subtype of hepatocellular carcinoma with unique morphological and molecular features.

PubMed

Wood, Laura D; Heaphy, Christopher M; Daniel, Hubert Darius-J; Naini, Bita V; Lassman, Charles R; Arroyo, May R; Kamel, Ihab R; Cosgrove, David P; Boitnott, John K; Meeker, Alan K; Torbenson, Michael S

2013-12-01

Hepatocellular carcinomas exhibit heterogeneous morphologies by routine light microscopy. Although some morphologies represent insignificant variations in growth patterns, others may represent unrecognized subtypes of hepatocellular carcinoma. Identification of these subtypes could lead to separation of hepatocellular carcinomas into discrete groups with unique underlying genetic changes, prognosis, or therapeutic responses. In order to identify potential subtypes, two pathologists independently screened a cohort of 219 unselected hepatocellular carcinoma resection specimens and divided cases into potential subtypes. One of these promising candidate subtypes was further evaluated using histological and molecular techniques. This subtype was characterized by a unique and consistent set of histological features: smooth chromophobic cytoplasm, abrupt focal nuclear anaplasia (small clusters of tumor cells with marked nuclear anaplasia in a background of tumor cells with bland nuclear cytology), and scattered microscopic pseudocysts--we designate this variant as 'chromophobe hepatocellular carcinoma with abrupt anaplasia'. Thirteen cases were identified (6% of all hepatocellular carcinomas), including 6 men and 7 women with an average age of 61 years. Six cases occurred in cirrhotic livers. Serum AFP was elevated in 6 out of 10 cases. There were a variety of underlying liver diseases, but cases were enrichment for chronic hepatitis B, P=0.006. Interestingly, at the molecular level, this variant was strongly associated with the alternative lengthening of telomere (ALT) phenotype by telomere FISH. ALT is a telomerase-independent mechanism of telomere maintenance and is found in approximately 8% of unselected hepatocellular carcinomas. In contrast, 11/12 (92%) of the cases of chromophobe hepatocellular carcinoma with abrupt anaplasia were ALT-positive. In summary, we propose that chromophobe hepatocellular carcinoma with abrupt anaplasia represents a new subtype of hepatocellular carcinoma with unique morphological and molecular features.

Morphological, molecular and ecological aspects of the South American hypogeous fungi Alpova austroalnicola sp. nov.

Treesearch

Eduardo R. Nouhra; Laura S. Domínguez; Alejandra G. Becerra; James M. Trappe

2005-01-01

Field studies in Argentina's Yunga District revealed Alpova austroalnicola sp. nov., a hypogeous fungus associated with Alnus acuminata ssp, acuminata. Morphological and molecular studies based on amplification and sequencing of the nuclear LSU rDNA gene showed its unique identity within ...

Comportement instationnaire des thermoéléments à effet Peltier multi-étages

NASA Astrophysics Data System (ADS)

Monchoux, F.; Zély, D.; Cordier, A.

1995-01-01

The analysis of thermoelectric phenomena is possible based on non-equilibrium thermodynamics. Integration of the thermal balance equation leads to an analytical solution for the non-stationnary behaviour. The influence to Thomson effect is commmented. The model, introduced in the complete software TRNSYS, permits the modelling of complex systems including such elements in their thermal regulation. La thermodynamique des processus irréversibles permet l'analyse des phénomènes thermoélectriques. Par intégration de l'équation de bilan thermique, on a obtenu une solution analytique pour le régime non stationnaire donnant la température en tous points et le flux absorbé. On a analysé l'influence de l'effet Thomson. Le modèle a été inclu dans le code plus général TRNSYS qui permet la modélisation de systèmes complexes.

Evidence for Early Morphological Decomposition in Visual Word Recognition

ERIC Educational Resources Information Center

Solomyak, Olla; Marantz, Alec

2010-01-01

We employ a single-trial correlational MEG analysis technique to investigate early processing in the visual recognition of morphologically complex words. Three classes of affixed words were presented in a lexical decision task: free stems (e.g., taxable), bound roots (e.g., tolerable), and unique root words (e.g., vulnerable, the root of which…

Patterns of differences in brain morphology in humans as compared to extant apes.

PubMed

Aldridge, Kristina

2011-01-01

Although human evolution is characterized by a vast increase in brain size, it is not clear whether or not certain regions of the brain are enlarged disproportionately in humans, or how this enlargement relates to differences in overall neural morphology. The aim of this study is to determine whether or not there are specific suites of features that distinguish the morphology of the human brain from that of apes. The study sample consists of whole brain, in vivo magnetic resonance images (MRIs) of anatomically modern humans (Homo sapiens sapiens) and five ape species (gibbons, orangutans, gorillas, chimpanzees, bonobos). Twenty-nine 3D landmarks, including surface and internal features of the brain were located on 3D MRI reconstructions of each individual using MEASURE software. Landmark coordinate data were scaled for differences in size and analyzed using Euclidean Distance Matrix Analysis (EDMA) to statistically compare the brains of each non-human ape species to the human sample. Results of analyses show both a pattern of brain morphology that is consistently different between all apes and humans, as well as patterns that differ among species. Further, both the consistent and species-specific patterns include cortical and subcortical features. The pattern that remains consistent across species indicates a morphological reorganization of 1) relationships between cortical and subcortical frontal structures, 2) expansion of the temporal lobe and location of the amygdala, and 3) expansion of the anterior parietal region. Additionally, results demonstrate that, although there is a pattern of morphology that uniquely defines the human brain, there are also patterns that uniquely differentiate human morphology from the morphology of each non-human ape species, indicating that reorganization of neural morphology occurred at the evolutionary divergence of each of these groups. Copyright © 2010 Elsevier Ltd. All rights reserved.

Patterns of differences in brain morphology in humans as compared to extant apes

PubMed Central

Aldridge, Kristina

2010-01-01

Although human evolution is characterized by a vast increase in brain size, it is not clear whether or not certain regions of the brain are enlarged disproportionately in humans, or how this enlargement relates to differences in overall neural morphology. The aim of this study is to determine whether or not there are specific suites of features that distinguish the morphology of the human brain from that of apes. The study sample consists of whole brain, in vivo magnetic resonance images (MRIs) of anatomically modern humans (Homo sapiens sapiens) and five ape species (gibbons, orangutans, gorillas, chimpanzees, bonobos). Twenty-nine 3D landmarks, including surface and internal features of the brain were located on 3D MRI reconstructions of each individual using MEASURE software. Landmark coordinate data were scaled for differences in size and analyzed using Euclidean Distance Matrix Analysis (EDMA) to statistically compare the brains of each non-human ape species to the human sample. Results of analyses show both a pattern of brain morphology that is consistently different between all apes and humans, as well as patterns that differ among species. Further, both the consistent and species-specific patterns include cortical and subcortical features. The pattern that remains consistent across species indicates a morphological reorganization of 1) relationships between cortical and subcortical frontal structures, 2) expansion of the temporal lobe and location of the amygdala, and 3) expansion of the anterior parietal region. Additionally, results demonstrate that, although there is a pattern of morphology that uniquely defines the human brain, there are also patterns that uniquely differentiate human morphology from the morphology of each non-human ape species, indicating that reorganization of neural morphology occurred at the evolutionary divergence of each of these groups. PMID:21056456

An embodied view of octopus neurobiology.

PubMed

Hochner, Binyamin

2012-10-23

Octopuses have a unique flexible body and unusual morphology, but nevertheless they are undoubtedly a great evolutionary success. They compete successfully with vertebrates in their ecological niche using a rich behavioral repertoire more typical of an intelligent predator which includes extremely effective defensive behavior--fast escape swimming and an astonishing ability to adapt their shape and color to their environment. The most obvious characteristic feature of an octopus is its eight long and flexible arms, but these pose a great challenge for achieving the level of motor and sensory information processing necessary for their behaviors. First, coordinating motion is a formidable task because of the infinite degrees of freedom that have to be controlled; and second, it is hard to use body coordinates in this flexible animal to represent sensory information in a central control system. Here I will review experimental results suggesting that these difficulties, arising from the animal's morphology, have imposed the evolution of unique brain/body/behavior relationships best explained as intelligent behavior which emerges from the octopus's embodied organization. The term 'intelligent embodiment' comes from robotics and refers to an approach to designing autonomous robots in which the behavior emerges from the dynamic physical and sensory interactions of the agent's materials, morphology and environment. Consideration of the unusual neurobiology of the octopus in the light of its unique morphology suggests that similar embodied principles are instrumental for understanding the emergence of intelligent behavior in all biological systems. Copyright © 2012 Elsevier Ltd. All rights reserved.

Facile chemical approach to ZnO submicrometer particles with controllable morphologies.

PubMed

Bardhan, Rizia; Wang, Hui; Tam, Felicia; Halas, Naomi J

2007-05-22

We have developed a simple wet-chemistry approach to fabricating ZnO submicrometer particles with unique morphologies including rings, bowls, hemispheres, and disks. The size and morphology of the particles can be conveniently tailored by varying the concentrations of the zinc precursor. The reaction temperature, pH, and concentration of ammonia are also found to play critical roles in directing the formation of these particle morphologies. These submicrometer particles exhibit strong white-light emission upon UV excitation as a result of the presence of surface defect states resulting from the fabrication method and synthesis conditions.

Unique Dental Morphology of Homo floresiensis and Its Evolutionary Implications

PubMed Central

Kaifu, Yousuke; Kono, Reiko T.; Sutikna, Thomas; Saptomo, Emanuel Wahyu; Jatmiko

2015-01-01

Homo floresiensis is an extinct, diminutive hominin species discovered in the Late Pleistocene deposits of Liang Bua cave, Flores, eastern Indonesia. The nature and evolutionary origins of H. floresiensis’ unique physical characters have been intensively debated. Based on extensive comparisons using linear metric analyses, crown contour analyses, and other trait-by-trait morphological comparisons, we report here that the dental remains from multiple individuals indicate that H. floresiensis had primitive canine-premolar and advanced molar morphologies, a combination of dental traits unknown in any other hominin species. The primitive aspects are comparable to H. erectus from the Early Pleistocene, whereas some of the molar morphologies are more progressive even compared to those of modern humans. This evidence contradicts the earlier claim of an entirely modern human-like dental morphology of H. floresiensis, while at the same time does not support the hypothesis that H. floresiensis originated from a much older H. habilis or Australopithecus-like small-brained hominin species currently unknown in the Asian fossil record. These results are however consistent with the alternative hypothesis that H. floresiensis derived from an earlier Asian Homo erectus population and experienced substantial body and brain size dwarfism in an isolated insular setting. The dentition of H. floresiensis is not a simple, scaled-down version of earlier hominins. PMID:26624612

Contributions of Morphological Skill to Children's Essay Writing

PubMed Central

Northey, Mary; McCutchen, Deborah; Sanders, Elizabeth A.

2015-01-01

Morphological skills have previously been found to reliably predict reading skill, including word reading, vocabulary, and comprehension. However, less is known about how morphological skills might contribute to writing skill, aside from its well-documented role in the development of spelling. This correlational study examines whether morphological skill, as measured by a sentence generation task tapping both derivational morphology and meta-syntactic skills, predicts performance on a standardized essay writing task for fifth- and eighth-grade U.S. students (N = 233), after controlling for grade level, comprehension, and writing fluency. Multilevel analyses indicated that morphological skill and writing fluency were each uniquely predictive of essay quality, and this finding was consistent regardless of whether accurate spelling was required in the morphological task. Our results suggest that morphological skills play an important role in writing, as has been previously documented in reading and spelling. PMID:26957783

Effets non lineaires transversaux dans les guides d'ondes plans

NASA Astrophysics Data System (ADS)

Dumais, Patrick

Les effets non lineaires transversaux dus a l'effet Kerr optique non resonant sont etudies dans deux types de guides a geometrie plane. D'abord (au chapitre 2), l'emission de solitons spatiaux d'un guide de type canal est etudie historiquement, analytiquement et numeriquement dans le but d'en faire la conception et la fabrication, en AlGaAs, dans la region spectrale en deca de la moitie de la bande interdite de ce materiau, soit autour de 1,5 microns. Le composant, tel que concu, comporte une structure de multipuits quantiques. Le desordonnement local de cette structure permet une variation locale du coefficient Kerr dans le guide, ce qui mene a l'emission d'un soliton spatial au-dela d'une puissance optique de seuil. L'observation experimentale d'un changement en fonction de l'intensite du profil de champ a la sortie du guide realise est presentee. Deuxiemement (au chapitre 3) une technique de mesure du coefficient Kerr dans un guide plan est presentee. Cette technique consiste a mesurer le changement de transmission au travers d'un cache place a la sortie du guide en fonction de l'intensite crete a l'entree du guide plan. Une methode pour determiner les conditions optimales pour la sensibilite de la mesure est presentee, illustree de plusieurs exemples. Finalement, la realisation d'un oscillateur parametrique optique basee sur un cristal de niobate de lithium a domaines periodiquement inverses est presentee. La theorie des oscillateurs parametriques optiques est exposee avec une emphase sur la generation d'impulsions intenses a des longueurs d'onde autour de 1,5 microns a partir d'un laser Ti:saphir, dans le but d'obtenir une source pour faire les experiences sur l'emission solitonique.

Distinct Morphology of Human T-Cell Leukemia Virus Type 1-Like Particles

PubMed Central

Maldonado, José O.; Cao, Sheng; Zhang, Wei; Mansky, Louis M.

2016-01-01

The Gag polyprotein is the main retroviral structural protein and is essential for the assembly and release of virus particles. In this study, we have analyzed the morphology and Gag stoichiometry of human T-cell leukemia virus type 1 (HTLV-1)-like particles and authentic, mature HTLV-1 particles by using cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission electron microscopy (STEM). HTLV-1-like particles mimicked the morphology of immature authentic HTLV-1 virions. Importantly, we have observed for the first time that the morphology of these virus-like particles (VLPs) has the unique local feature of a flat Gag lattice that does not follow the curvature of the viral membrane, resulting in an enlarged distance between the Gag lattice and the viral membrane. Other morphological features that have been previously observed with other retroviruses include: (1) a Gag lattice with multiple discontinuities; (2) membrane regions associated with the Gag lattice that exhibited a string of bead-like densities at the inner leaflet; and (3) an arrangement of the Gag lattice resembling a railroad track. Measurement of the average size and mass of VLPs and authentic HTLV-1 particles suggested a consistent range of size and Gag copy numbers in these two groups of particles. The unique local flat Gag lattice morphological feature observed suggests that HTLV-1 Gag could be arranged in a lattice structure that is distinct from that of other retroviruses characterized to date. PMID:27187442

Effect of phonological and morphological awareness on reading comprehension in Hebrew-speaking adolescents with reading disabilities.

PubMed

Schiff, Rachel; Schwartz-Nahshon, Sarit; Nagar, Revital

2011-06-01

This research explored phonological and morphological awareness among Hebrew-speaking adolescents with reading disabilities (RD) and its effect on reading comprehension beyond phonological and word-reading abilities. Participants included 39 seventh graders with RD and two matched control groups of normal readers: 40 seventh graders matched for chronological age (CA) and 38 third graders matched for reading age (RA). We assessed phonological awareness, word reading, morphological awareness, and reading comprehension. Findings indicated that the RD group performed similarly to the RA group on phonological awareness but lower on phonological decoding. On the decontextualized morphological task, RD functioned on par with RA, whereas in a contextualized task RD performed above RA but lower than CA. In reading comprehension, RD performed as well as RA. Finally, results indicated that for normal readers contextual morphological awareness uniquely contributed to reading comprehension beyond phonological and word-reading abilities, whereas no such unique contribution emerged for the RD group. The absence of an effect of morphological awareness in predicting reading comprehension was suggested to be related to a different recognition process employed by RD readers which hinder the ability of these readers to use morphosemantic structures. The lexical quality hypothesis was proposed as further support to the findings, suggesting that a low quality of lexical representation in RD students leads to ineffective reading skills and comprehension. Lexical representation is thus critical for both lexical as well as comprehension abilities.

A Quantile Regression Approach to Understanding the Relations among Morphological Awareness, Vocabulary, and Reading Comprehension in Adult Basic Education Students

ERIC Educational Resources Information Center

Tighe, Elizabeth L.; Schatschneider, Christopher

2016-01-01

The purpose of this study was to investigate the joint and unique contributions of morphological awareness and vocabulary knowledge at five reading comprehension levels in adult basic education (ABE) students. We introduce the statistical technique of multiple quantile regression, which enabled us to assess the predictive utility of morphological…

The Contributions of Phonological and Morphological Awareness to Literacy Skills in the Adult Basic Education Population

ERIC Educational Resources Information Center

Fracasso, Lucille E.; Bangs, Kathryn; Binder, Katherine S.

2016-01-01

The Adult Basic Education (ABE) population consists of a wide range of abilities with needs that may be unique to this set of learners. The purpose of this study was to better understand the relative contributions of phonological decoding and morphological awareness to spelling, vocabulary, and comprehension across a sample of ABE students. In…

Evolution of thorax architecture in ant castes highlights trade-off between flight and ground behaviors

PubMed Central

Keller, Roberto A; Peeters, Christian; Beldade, Patrícia

2014-01-01

The concerted evolution of morphological and behavioral specializations has compelling examples in ant castes. Unique to ants is a marked divergence between winged queens and wingless workers, but morphological specializations for behaviors on the ground have been overlooked. We analyzed thorax morphology of queens and workers in species from 21 of the 25 ant subfamilies. We uncovered unique skeletomuscular modifications in workers that presumably increase power and flexibility of head–thorax articulation, emphasizing that workers are not simply wingless versions of queens. We also identified two distinct types of queens and showed repeated evolutionary associations with strategies of colony foundation. Solitary founding queens that hunt have a more worker-like thorax. Our results reveal that ants invest in the relative size of thorax segments according to their tasks. Versatility of head movements allows for better manipulation of food and objects, which arguably contributed to the ants’ ecological and evolutionary success. DOI: http://dx.doi.org/10.7554/eLife.01539.001 PMID:24399458

Evolution of thorax architecture in ant castes highlights trade-off between flight and ground behaviors.

PubMed

Keller, Roberto A; Peeters, Christian; Beldade, Patrícia

2014-01-01

The concerted evolution of morphological and behavioral specializations has compelling examples in ant castes. Unique to ants is a marked divergence between winged queens and wingless workers, but morphological specializations for behaviors on the ground have been overlooked. We analyzed thorax morphology of queens and workers in species from 21 of the 25 ant subfamilies. We uncovered unique skeletomuscular modifications in workers that presumably increase power and flexibility of head-thorax articulation, emphasizing that workers are not simply wingless versions of queens. We also identified two distinct types of queens and showed repeated evolutionary associations with strategies of colony foundation. Solitary founding queens that hunt have a more worker-like thorax. Our results reveal that ants invest in the relative size of thorax segments according to their tasks. Versatility of head movements allows for better manipulation of food and objects, which arguably contributed to the ants' ecological and evolutionary success. DOI: http://dx.doi.org/10.7554/eLife.01539.001.

Diet-Morphology Correlations in the Radiation of South American Geophagine Cichlids (Perciformes: Cichlidae: Cichlinae)

PubMed Central

López-Fernández, Hernán; Winemiller, Kirk O.; Montaña, Carmen; Honeycutt, Rodney L.

2012-01-01

Genera within the South American cichlid tribe Geophagini display specialized feeding and reproductive strategies, with some taxa specialized for both substrate-sifting and mouth brooding. Several lineages within the clade also possess an epibranchial lobe (EBL), a unique pharyngeal structure that has been proposed to have a function in feeding and/or mouth brooding. A recently published genus-level phylogeny of Neotropical cichlids was used as the evolutionary framework for investigating the evolution of morphological features presumably correlated with diet and mouth brooding in the tribe Geophagini. We tested for possible associations between the geophagine epibranchial lobe and benthic feeding and mouth brooding. We also addressed whether the EBL may be associated with unique patterns of diversification in certain geophagine clades. Tests of binary character correlations revealed the EBL was significantly associated with mouth brooding. We also tested for a relationship between diet and morphology. We analyzed stomach contents and morphometric variation among 21 species, with data for two additional species obtained from the literature. Principal Components Analysis revealed axes of morphological variation significantly correlated with piscivory and benthivory, and both morphology and diet were significantly associated with phylogeny. These results suggest that the EBL could be an adaptation for either feeding or mouth brooding. The EBL, however, was not associated with species richness or accelerated rates of phyletic diversification. PMID:22485154

Pythons in Burma: Short-tailed python (Reptilia: Squamata)

USGS Publications Warehouse

Zug, George R.; Gotte, Steve W.; Jacobs, Jeremy F.

2011-01-01

Short-tailed pythons, Python curtus species group, occur predominantly in the Malayan Peninsula, Sumatra, and Borneo. The discovery of an adult female in Mon State, Myanmar, led to a review of the distribution of all group members (spot-mapping of all localities of confirmed occurrence) and an examination of morphological variation in P. brongersmai. The resulting maps demonstrate a limited occurrence of these pythons within peninsular Malaya, Sumatra, and Borneo with broad absences in these regions. Our small samples limit the recognition of regional differentiation in the morphology of P. brongersmai populations; however, the presence of unique traits in the Myanmar python and its strong allopatry indicate that it is a unique genetic lineage, and it is described as Python kyaiktiyo new species.

Nanostructured Metal Oxides for Stoichiometric Degradation of Chemical Warfare Agents.

PubMed

Štengl, Václav; Henych, Jiří; Janoš, Pavel; Skoumal, Miroslav

2016-01-01

Metal oxides have very important applications in many areas of chemistry, physics and materials science; their properties are dependent on the method of preparation, the morphology and texture. Nanostructured metal oxides can exhibit unique characteristics unlike those of the bulk form depending on their morphology, with a high density of edges, corners and defect surfaces. In recent years, methods have been developed for the preparation of metal oxide powders with tunable control of the primary particle size as well as of a secondary particle size: the size of agglomerates of crystallites. One of the many ways to take advantage of unique properties of nanostructured oxide materials is stoichiometric degradation of chemical warfare agents (CWAs) and volatile organic compounds (VOC) pollutants on their surfaces.

Synthesis of multi-hierarchical structured yttria-stabilized zirconia powders and their enhanced thermophysical properties

NASA Astrophysics Data System (ADS)

Cao, Fengmei; Gao, Yanfeng; Chen, Hongfei; Liu, Xinling; Tang, Xiaoping; Luo, Hongjie

2013-06-01

Multi-hierarchical structured yttria-stabilized zirconia (YSZ) powders were successfully synthesized by a hydrothermal-calcination process. The morphology, crystallinity, and microstructure of the products were characterized by SEM, XRD, TEM, and BET. A possible formation mechanism of the unique structure formed during hydrothermal processing was also investigated. The measured thermophysical results indicated that the prepared YSZ powders had a low thermal conductivity (0.63-1.27 W m-1 K-1), good short-term high-temperature stability up to 1300 °C. The influence of the morphology and microstructure on their thermophysical properties was briefly discussed. The unique multi-hierarchical structure makes the prepared YSZ powders candidates for use in enhanced applications involving thermal barrier coatings.

Morphology and Photometry of Isolated Seyfert Galaxies

NASA Astrophysics Data System (ADS)

Cracco, V.; Ciroi, S.; di Mille, F.; Omizzolo, A.; Funes, J. G.; Rafanelli, P.

2008-10-01

An unresolved and intriguing problem about active galactic nuclei is the mechanism responsible for nuclear triggering and fueling. Until now there is not a unique solution that can completely explain this phenomenon. We present preliminary results about morphological and photometric analysis of a sample of 35 nearby (z<0.035) and isolated Seyfert galaxies, observed through broad-band BVR filters at the 1.8-m Vatican Telescope and the 2.2-m ESO-La Silla Telescope. We analyzed photometric and morphological parameters and, using GALFIT software, we obtained two-dimensional decomposition of the luminosity profiles.

From Morphology to Neural Information: The Electric Sense of the Skate

PubMed Central

Camperi, Marcelo; Tricas, Timothy C; Brown, Brandon R

2007-01-01

Morphology typically enhances the fidelity of sensory systems. Sharks, skates, and rays have a well-developed electrosense that presents strikingly unique morphologies. Here, we model the dynamics of the peripheral electrosensory system of the skate, a dorsally flattened batoid, moving near an electric dipole source (e.g., a prey organism). We compute the coincident electric signals that develop across an array of the skate's electrosensors, using electrodynamics married to precise morphological measurements of sensor location, infrastructure, and vector projection. Our results demonstrate that skate morphology enhances electrosensory information. Not only could the skate locate prey using a simple population vector algorithm, but its morphology also specifically leads to quick shifts in firing rates that are well-suited to the demonstrated bandwidth of the electrosensory system. Finally, we propose electrophysiology trials to test the modeling scheme. PMID:17571918

Effetive methods in educating extension agents and farmers on conservation farming technology

USDA-ARS?s Scientific Manuscript database

Adoption of new technologies requires transfer of information from developers to end users. Efficiency of the transfer process influences the rate of adoption and ultimate impact of the technology. Various channels are used to transfer technology from researchers to farmers. Two commonly used ones ...

Future of Software Engineering Standards

NASA Technical Reports Server (NTRS)

Poon, Peter T.

1997-01-01

In the new millennium, software engineering standards are expected to continue to influence the process of producing software-intensive systems which are cost-effetive and of high quality. These sytems may range from ground and flight systems used for planetary exploration to educational support systems used in schools as well as consumer-oriented systems.

Effet Bauschinger lors de la plasticité cyclique de l'aluminium pur monocristallin

NASA Astrophysics Data System (ADS)

Alhamany, A.; Chicois, J.; Fougères, R.; Hamel, A.

1992-08-01

This paper is concerned with the study of microscopic mechanisms which control the cyclic deformation of pure aluminium and especially with the analysis of the Bauschinger effect which appears in aluminium single crystals deformed by cyclic straining. Fatigue tests are performed on Al single crystals with the crystal axis parallel to [ overline{1}23] at room temperature, at plastic shear strain amplitudes in the range from 10^{-4} to 3× 10^{-3}. Mechanical saturation is not obtained at any strain level. Instead, a hardening-softening-secondary hardening sequence is found. The magnitude of the Bauschinger effect as the difference between yield stresses in traction and in compression, changes all along the fatigue loop and during the fatigue test. The Bauschinger effect disappears at two points of the fatigue loop, one in the traction part, the other in the compression one. At these points, the Bauschinger effect is inverted. Dislocation arrangement evolutions with fatigue conditions can explain the cyclic behaviour of Al single crystals. An heterogeneous dislocation distribution can be observed in the cyclically strained metal : dislocation tangles, long dislocation walls and dislocation cell walls, separated by dislocation poor channels appear in the material as a function of the cycle number. The long range internal stress necessary to ensure the compatibility of deformation between the hard and soft regions controls the observed Bauschinger effect. Ce travail s'inscrit dans le cadre de l'étude des mécanismes microsocopiques intervenant lors de la déformation cyclique de l'aluminium pur et concerne en particulier l'analyse de l'effet Bauschinger apparaissant au cours de la solliciation cyclique des monocristaux. L'étude a été menée à température ambiante sur des monocristaux d'aluminium pur orientés pour un glissement simple (axe [ overline{1}23] ), à des amplitudes de déformation plastique comprise entre 10^{-4} et quelques 10^{-3}. Nous n'avons pas obtenu de véritable saturation mécanique. Nous sommes en présence d'une séquence durcissement-adoucissement-durcissement secondaire. L'amplitude de l'effet Bauschinger considéré comme la différence entre les limites élastiques en traction et en compression mesurées selon une procédure appropriée, évolue le long d'une boucle de fatigue, s'annule pour deux points particuliers l'un en traction l'autre en compression. De part et d'autre de ces points, le signe de l'effet Bauschinger est inversé. Les microstructures des états fatigués sont caractérisés par une répartition hétérogène des dislocations constituée d'amas, de murs ou des parois, suivant le degré de déformation cyclique, séparés par des zones à faible densité de dislocations. Les contraintes internes liées aux incompatibilités de déformation résultant de cette répartition hétérogène des dislocations sont à l'origine de l'effet Bauschinger observé dans les monocristaux. Ces contraintes et l'évolution de la quantité de cellules de dislocations avec la fatigue expliquent le durcissement secondaire.

Gorilla-like anatomy on Australopithecus afarensis mandibles suggests Au. afarensis link to robust australopiths

PubMed Central

Rak, Yoel; Ginzburg, Avishag; Geffen, Eli

2007-01-01

Mandibular ramus morphology on a recently discovered specimen of Australopithecus afarensis closely matches that of gorillas. This finding was unexpected given that chimpanzees are the closest living relatives of humans. Because modern humans, chimpanzees, orangutans, and many other primates share a ramal morphology that differs from that of gorillas, the gorilla anatomy must represent a unique condition, and its appearance in fossil hominins must represent an independently derived morphology. This particular morphology appears also in Australopithecus robustus. The presence of the morphology in both the latter and Au. afarensis and its absence in modern humans cast doubt on the role of Au. afarensis as a modern human ancestor. The ramal anatomy of the earlier Ardipithecus ramidus is virtually that of a chimpanzee, corroborating the proposed phylogenetic scenario. PMID:17426152

Gorilla-like anatomy on Australopithecus afarensis mandibles suggests Au. afarensis link to robust australopiths.

PubMed

Rak, Yoel; Ginzburg, Avishag; Geffen, Eli

2007-04-17

Mandibular ramus morphology on a recently discovered specimen of Australopithecus afarensis closely matches that of gorillas. This finding was unexpected given that chimpanzees are the closest living relatives of humans. Because modern humans, chimpanzees, orangutans, and many other primates share a ramal morphology that differs from that of gorillas, the gorilla anatomy must represent a unique condition, and its appearance in fossil hominins must represent an independently derived morphology. This particular morphology appears also in Australopithecus robustus. The presence of the morphology in both the latter and Au. afarensis and its absence in modern humans cast doubt on the role of Au. afarensis as a modern human ancestor. The ramal anatomy of the earlier Ardipithecus ramidus is virtually that of a chimpanzee, corroborating the proposed phylogenetic scenario.

The unique stem cell system of the immortal larva of the human parasite Echinococcus multilocularis

PubMed Central

2014-01-01

Background It is believed that in tapeworms a separate population of undifferentiated cells, the germinative cells, is the only source of cell proliferation throughout the life cycle (similar to the neoblasts of free living flatworms). In Echinococcus multilocularis, the metacestode larval stage has a unique development, growing continuously like a mass of vesicles that infiltrate the tissues of the intermediate host, generating multiple protoscoleces by asexual budding. This unique proliferation potential indicates the existence of stem cells that are totipotent and have the ability for extensive self-renewal. Results We show that only the germinative cells proliferate in the larval vesicles and in primary cell cultures that undergo complete vesicle regeneration, by using a combination of morphological criteria and by developing molecular markers of differentiated cell types. The germinative cells are homogeneous in morphology but heterogeneous at the molecular level, since only sub-populations express homologs of the post-transcriptional regulators nanos and argonaute. Important differences are observed between the expression patterns of selected neoblast marker genes of other flatworms and the E. multilocularis germinative cells, including widespread expression in E. multilocularis of some genes that are neoblast-specific in planarians. Hydroxyurea treatment results in the depletion of germinative cells in larval vesicles, and after recovery following hydroxyurea treatment, surviving proliferating cells grow as patches that suggest extensive self-renewal potential for individual germinative cells. Conclusions In E. multilocularis metacestodes, the germinative cells are the only proliferating cells, presumably driving the continuous growth of the larval vesicles. However, the existence of sub-populations of the germinative cells is strongly supported by our data. Although the germinative cells are very similar to the neoblasts of other flatworms in function and in undifferentiated morphology, their unique gene expression pattern and the evolutionary loss of conserved stem cells regulators suggest that important differences in their physiology exist, which could be related to the unique biology of E. multilocularis larvae. PMID:24602211

The unique stem cell system of the immortal larva of the human parasite Echinococcus multilocularis.

PubMed

Koziol, Uriel; Rauschendorfer, Theresa; Zanon Rodríguez, Luis; Krohne, Georg; Brehm, Klaus

2014-03-06

It is believed that in tapeworms a separate population of undifferentiated cells, the germinative cells, is the only source of cell proliferation throughout the life cycle (similar to the neoblasts of free living flatworms). In Echinococcus multilocularis, the metacestode larval stage has a unique development, growing continuously like a mass of vesicles that infiltrate the tissues of the intermediate host, generating multiple protoscoleces by asexual budding. This unique proliferation potential indicates the existence of stem cells that are totipotent and have the ability for extensive self-renewal. We show that only the germinative cells proliferate in the larval vesicles and in primary cell cultures that undergo complete vesicle regeneration, by using a combination of morphological criteria and by developing molecular markers of differentiated cell types. The germinative cells are homogeneous in morphology but heterogeneous at the molecular level, since only sub-populations express homologs of the post-transcriptional regulators nanos and argonaute. Important differences are observed between the expression patterns of selected neoblast marker genes of other flatworms and the E. multilocularis germinative cells, including widespread expression in E. multilocularis of some genes that are neoblast-specific in planarians. Hydroxyurea treatment results in the depletion of germinative cells in larval vesicles, and after recovery following hydroxyurea treatment, surviving proliferating cells grow as patches that suggest extensive self-renewal potential for individual germinative cells. In E. multilocularis metacestodes, the germinative cells are the only proliferating cells, presumably driving the continuous growth of the larval vesicles. However, the existence of sub-populations of the germinative cells is strongly supported by our data. Although the germinative cells are very similar to the neoblasts of other flatworms in function and in undifferentiated morphology, their unique gene expression pattern and the evolutionary loss of conserved stem cells regulators suggest that important differences in their physiology exist, which could be related to the unique biology of E. multilocularis larvae.

PHOTOSYNTHETIC PIGMENT AND GENETIC DIFFERENCES BETWEEN TWO SOUTHERN OCEAN MORPHOTYPES OF EMILIANIA HUXLEYI (HAPTOPHYTA)1.

PubMed

Cook, Suellen S; Whittock, Lucy; Wright, Simon W; Hallegraeff, Gustaaf M

2011-06-01

The widespread coccolithophorid Emiliania huxleyi (Lohmann) W. W. Hay et H. Mohler plays a pivotal role in the carbon pump and is known to exhibit significant morphological, genetic, and physiological diversity. In this study, we compared photosynthetic pigments and morphology of triplicate strains of Southern Ocean types A and B/C. The two morphotypes differed in width of coccolith distal shield elements (0.11-0.24 μm, type A; 0.06-0.12 μm, type B/C) and morphology of distal shield central area (grill of curved rods in type A; thin plain plate in type B/C) and showed differences in carotenoid composition. The mean 19'-hexanoyloxyfucoxanthin (Hex):chl a ratio in type B/C was >1, whereas the type A ratio was <1. The Hex:fucoxanthin (fuc) ratio for type B/C was 11 times greater than that for type A, and the proportion of fuc in type A was 6 times higher than that in type B/C. The fuc derivative 4-keto-19'-hexanoyloxyfucoxanthin (4-keto-hex) was present in type A but undetected in B/C. DNA sequencing of tufA distinguished morphotypes A, B/C (indistinguishable from B), and R, while little variation was observed within morphotypes. Thirty single nucleotide polymorphisms were identified in the 710 bp tufA sequence, of which 10 alleles were unique to B/C and B morphotypes, seven alleles were unique to type A, and six alleles were unique to type R. We propose that the morphologically, physiologically, and genetically distinct Southern Ocean type B/C sensu Young et al. (2003) be classified as E. huxleyi var. aurorae var. nov. S. S. Cook et Hallegr. © 2011 Phycological Society of America.

Adaptation of sensor morphology: an integrative view of perception from biologically inspired robotics perspective

PubMed Central

Nurzaman, Surya G.

2016-01-01

Sensor morphology, the morphology of a sensing mechanism which plays a role of shaping the desired response from physical stimuli from surroundings to generate signals usable as sensory information, is one of the key common aspects of sensing processes. This paper presents a structured review of researches on bioinspired sensor morphology implemented in robotic systems, and discusses the fundamental design principles. Based on literature review, we propose two key arguments: first, owing to its synthetic nature, biologically inspired robotics approach is a unique and powerful methodology to understand the role of sensor morphology and how it can evolve and adapt to its task and environment. Second, a consideration of an integrative view of perception by looking into multidisciplinary and overarching mechanisms of sensor morphology adaptation across biology and engineering enables us to extract relevant design principles that are important to extend our understanding of the unfinished concepts in sensing and perception. PMID:27499843

The role of morphological awareness in reading comprehension among typical and learning disabled native Arabic speakers.

PubMed

Mahfoudhi, Abdessatar; Elbeheri, Gad; Al-Rashidi, Mousa; Everatt, John

2010-01-01

This work examines the role of morphological awareness in contrast to phonological processing in reading comprehension amongst two groups of native Arabic children: a group with learning disabilities (LD) and a mainstream group who were matched to the LD group in age or reading level. Measures of reading comprehension fluency, phonological skills, and morphological ability were given to both groups in addition to tests of nonverbal ability. For the mainstream children, unique variability in comprehension was predicted by the morphological measures over that of the measures of phonological skills and general nonverbal ability. In contrast, for the LD data, variability in comprehension was not predicted by morphological ability even though the children with LD performed the morphology task as well as their typically developing peers did. These findings are discussed in terms of theories of reading acquisition across languages as well as recommendations for literacy teaching and LD intervention in Arabic.

Novel multistep BRET-FRET energy transfer using nanoconjugates of firefly proteins, quantum dots, and red fluorescent proteins

NASA Astrophysics Data System (ADS)

Alam, Rabeka; Zylstra, Joshua; Fontaine, Danielle M.; Branchini, Bruce R.; Maye, Mathew M.

2013-05-01

Sequential bioluminescence resonance energy transfer (BRET) and fluorescence resonance energy transfer (FRET) from firefly luciferase to red fluorescent proteins using quantum dot or rod acceptor/donor linkers is described. The effect of morphology and tuned optical properties on the efficiency of this unique BRET-FRET system was evaluated.Sequential bioluminescence resonance energy transfer (BRET) and fluorescence resonance energy transfer (FRET) from firefly luciferase to red fluorescent proteins using quantum dot or rod acceptor/donor linkers is described. The effect of morphology and tuned optical properties on the efficiency of this unique BRET-FRET system was evaluated. Electronic supplementary information (ESI) available: Experimental details, Fig. S1 and Table S1-S4. See DOI: 10.1039/c3nr01842c

Morphology and force probing of primary murine liver sinusoidal endothelial cells.

PubMed

Zapotoczny, B; Owczarczyk, K; Szafranska, K; Kus, E; Chlopicki, S; Szymonski, M

2017-07-01

Liver sinusoidal endothelial cells (LSECs) represent unique type of endothelial cells featured by their characteristic morphology, ie, lack of a basement membrane and presence of fenestrations-transmembrane pores acting as a dynamic filter between the vascular space and the liver parenchyma. Delicate structure of LSECs membrane combined with a submicron size of fenestrations hinders their visualization in live cells. In this work, we apply atomic force microscopy contact mode to characterize fenestrations in LSECs. We reveal the structure of fenestrations in live LSECs. Moreover, we show that the high-resolution imaging of fenestrations is possible for the glutaraldehyde-fixed LSECs. Finally, thorough information about the morphology of LSECs including great contrast in visualization of sieve plates and fenestrations is provided using Force Modulation mode. We show also the ability to precisely localize the cell nuclei in fixed LSECs. It can be helpful for more precise description of nanomechanical properties of cell nuclei using atomic force microscopy. Presented methodology combining high-quality imaging of fixed cells with an additional nanomechanical information of both live and fixed LSECs provides a unique approach to study LSECs morphology and nanomechanics that could foster understanding of the role of LSECs in maintaining liver homeostasis. Copyright © 2017 John Wiley & Sons, Ltd.

Cranial morphology of Javanese Homo erectus: new evidence for continuous evolution, specialization, and terminal extinction.

PubMed

Kaifu, Yousuke; Aziz, Fachroel; Indriati, Etty; Jacob, Teuku; Kurniawan, Iwan; Baba, Hisao

2008-10-01

Our current knowledge of the evolution of Homo during the early to middle Pleistocene is far from complete. This is not only because of the small number of fossil samples available, but also due to the scarcity of standardized datasets which are reliable in terms of landmark identification, interobserver error, and other distorting factors. This study aims to accurately describe the cranial morphological changes of H. erectus in Java using a standardized set of measurements taken by the authors from 18 adult crania from Sangiran, Trinil, Sambungmacan, and Ngandong. The identification of some obscure landmarks was aided by the use of micro-CT imaging. While recent studies tend to emphasize evolutionary conservatism in Javanese H. erectus, our results reinforce the theory that chronologically later groups experienced distinct morphological changes in a number of cranial traits. Some of these changes, particularly those related to brain size expansion, are similar to those observed for the genus Homo as a whole, whereas others are apparently unique specializations restricted to Javanese H. erectus. Such morphological specializations in Java include previously undescribed anteroposterior lengthening of the midcranial base and an anterior shift of the posterior temporal muscle, which might have influenced the morphology of the angular torus and supramastoid sulcus. Analyses of morphological variation indicate that the three crania from Sambungmacan variously fill the morphological gap between the chronologically earlier (Bapang-AG, Bapang Formation above the Grenzbank zone in Sangiran) and later (Ngandong) morphotypes of Java. At least one of the Bapang-AG crania, Sangiran 17, also exhibits a few characteristics which potentially indicate evolution toward the Ngandong condition. These strongly suggest the continuous, gradual morphological evolution of Javanese H. erectus from the Bapang-AG to Ngandong periods. The development of some unique features in later Javanese H. erectus supports the hypothesis that this Javanese lineage went extinct without making significant contributions to the ancestry of modern humans.

ERMO3/MVP1/GOLD36 Is Involved in a Cell Type-Specific Mechanism for Maintaining ER Morphology in Arabidopsis thaliana

PubMed Central

Nakano, Ryohei Thomas; Matsushima, Ryo; Nagano, Atsushi J.; Fukao, Yoichiro; Fujiwara, Masayuki; Kondo, Maki; Nishimura, Mikio; Hara-Nishimura, Ikuko

2012-01-01

The endoplasmic reticulum (ER) has a unique, network-like morphology. The ER structures are composed of tubules, cisternae, and three-way junctions. This morphology is highly conserved among eukaryotes, but the molecular mechanism that maintains ER morphology has not yet been elucidated. In addition, certain Brassicaceae plants develop a unique ER-derived organelle called the ER body. This organelle accumulates large amounts of PYK10, a β-glucosidase, but its physiological functions are still obscure. We aimed to identify a novel factor required for maintaining the morphology of the ER, including ER bodies, and employed a forward-genetic approach using transgenic Arabidopsis thaliana (GFP-h) with fluorescently-labeled ER. We isolated and investigated a mutant (designated endoplasmic reticulum morphology3, ermo3) with huge aggregates and abnormal punctate structures of ER. ERMO3 encodes a GDSL-lipase/esterase family protein, also known as MVP1. Here, we showed that, although ERMO3/MVP1/GOLD36 was expressed ubiquitously, the morphological defects of ermo3 were specifically seen in a certain type of cells where ER bodies developed. Coimmunoprecipitation analysis combined with mass spectrometry revealed that ERMO3/MVP1/GOLD36 interacts with the PYK10 complex, a huge protein complex that is thought to be important for ER body-related defense systems. We also found that the depletion of transcription factor NAI1, a master regulator for ER body formation, suppressed the formation of ER-aggregates in ermo3 cells, suggesting that NAI1 expression plays an important role in the abnormal aggregation of ER. Our results suggest that ERMO3/MVP1/GOLD36 is required for preventing ER and other organelles from abnormal aggregation and for maintaining proper ER morphology in a coordinated manner with NAI1. PMID:23155454

Deuterium Isotope Effects During HMX Combustion: Chemical Kinetic Burn Rate Control Mechanism Verified

DTIC Science & Technology

1989-01-01

experience de gen dieses Experiments. Der 10 KDIE-Wert legt nahe. dab die combustion statique. La valeur de l’effet isotopique primaire laisse...anomaler combustion globale. Des 6tudes publifes par ailleurs confirment cette KDIE-Wert bei 10,4 MPa wirL angegeben. Diese KDIE-Experimente hypoth~se

Effets pathogènes d'un faible débit de dose : la relation « dose effet »

NASA Astrophysics Data System (ADS)

Masse, Roland

2002-10-01

There is no evidence of pathogenic effects in human groups exposed to less than 100 mSv at low dose-rate. The attributed effects are therefore the result of extrapolations from higher doses. The validity of such extrapolations is discussed from the point of view of epidemiology as well as cellular and molecular biology. The Chernobyl accident resulted in large excess of thyroid cancers in children; it also raised the point that some actual sanitary effects among distressed populations might be a direct consequence of low doses. Studies under the control of UN have not confirmed this point identifying no dose-effect relationship and " severe socio-economic and psychological pressures… poverty, poor diet and living conditions, and lifestyle factors" as the main cause for depressed health. Some hypothesis are considered for explaining the dose-dependence and high prevalence of non-cancer causes of death among human groups exposed to more than 300 mSv. To cite this article: R. Masse, C. R. Physique 3 (2002) 1049-1058.

Fiabilité des structures mécaniques adaptatives: effet de la panne des actionneurs ou des capteurs sur la stabilité

NASA Astrophysics Data System (ADS)

Fall, H.; Charon, W.; Kouta, R.

2002-12-01

Ces dernières décennies, des activités significatives dans le monde étaient dirigées autour du contrôle actif. Le but de ces recherches était essentiellement d'améliorer les performances, la fiabilité et la sécurité des systèmes. Notamment dans le cas des structures soumises à des vibrations aléatoires. D'importants travaux ont été consacré à l'utilisation des “matériaux intelligents” comme capteurs et actionneurs. Cette article propose l'analyse de la fiabilité des systèmes mécaniques en étudiant les pannes des actionneurs ou des capteurs. L'effet de ces pannes sur la stabilité et la performance du système y est démontré. Les méthodologies de conception y sont rappelées. Des exemples numériques sont fournis à travers le contrôle d'un panneau sous chargement dynamique pour illustrer la méthode proposée.

The relation of linguistic awareness and vocabulary to word reading and spelling for first grade students participating in Response to Intervention

PubMed Central

Kim, Young-Suk; Apel, Kenn; Otaiba, Stephanie Al

2013-01-01

Purpose We examined the relations of phonological, morphological, and orthographic awareness and vocabulary to word reading and spelling for first grade children who were receiving differentiated instruction in a Response to Intervention (RTI) model of instruction (N = 304). Method First grade children were assessed on their phonological, morphological, and orthographic awareness, expressive vocabulary, word reading, and spelling. Year-end word reading and spelling were outcome variables while phonological, morphological, and orthographic awareness, expressive vocabulary, and RTI status (Tiers 1, 2, & 3) were predictor variables assessed in the middle of the school year. Results The three linguistic awareness skills were unique predictors of word reading and phonological and orthographic awareness were unique predictors of spelling. The contributions these linguistic awareness skills and vocabulary made to word reading and spelling did not differ by children's RTI tier status. Conclusion These results, in conjunction with previous studies, suggest that even beginning readers and spellers draw on multiple linguistic awareness skills for their word reading and spelling regardless of their level of literacy skills. Educational implications are discussed. PMID:23833281

The relation of linguistic awareness and vocabulary to word reading and spelling for first-grade students participating in response to intervention.

PubMed

Kim, Young-Suk; Apel, Kenn; Al Otaiba, Stephanie

2013-10-01

The relations of phonological, orthographic, and morphological awareness and vocabulary to word reading and spelling were examined for 304 first-grade children who were receiving differentiated instruction in a Response to Intervention (RtI) model of instruction. First-grade children were assessed on their phonological, orthographic, and morphological awareness; expressive vocabulary; word reading; and spelling. Year-end word reading and spelling were outcome variables, and phonological, orthographic, and morphological awareness; expressive vocabulary; and RtI status (Tiers 1, 2, & 3) were predictor variables. The 3 linguistic awareness skills were unique predictors of word reading, and phonological and orthographic awareness were unique predictors of spelling. The contributions that these linguistic awareness skills and vocabulary made to word reading and spelling did not differ by children's RtI tier status. These results, in conjunction with previous studies, suggest that even beginning readers and spellers draw on multiple linguistic awareness skills for their word reading and spelling regardless of their level of literacy abilities. Educational implications are discussed.

Facilely prepared, N, O-codoped nanosheet derived from pre-functionalized polymer as supercapacitor electrodes

NASA Astrophysics Data System (ADS)

Wang, Jun; Yang, Ting; Zeng, Zheling; Deng, Shuguang

2018-04-01

Nitrogen and oxygen codoped carbon nanosheets derived from pre-functionalized polymer were prepared using a facile direct pyrolysis method. The carbon microstructures are tunable with micro- and mesopore size distribution and a large specific surface area (1628.9-2146.1 m2 g-1). Furthermore, a significant morphology change, from carbon granules to carbon nanosheets, occurred at an annealing temperature of 1273 K. The unique carbon sheet morphology guaranteed a good specific capacitance of 246.4 F g-1 at 0.5 A g-1 in 1 M H2SO4 aqueous solution and an excellent rate capability with a retention of 87.9% at 5 A g-1 as coin cell. The outstanding capacitance attributes to the combination of pseudocapacitance due to the N,O dual-doping and unique nanosheet morphology. Moreover, its outstanding cycling performance with 95% retention over 10,000 cycles at 10 A g-1 and an acceptable energy density of 8.6 Wh kg-1 at 0.2 A g-1 make the N,O-codoped carbon nanosheet potent and promising electrode material for high performance supercapacitors.

Morphological changes in human melanoma cells following irradiation with thermal neutrons.

PubMed

Barkla, D H; Allen, B J; Brown, J K; Mountford, M; Mishima, Y; Ichihashi, M

1989-01-01

Morphological changes in two human melanoma cell lines, MM96 and MM418, following irradiation with thermal neutrons, were studied using light and electron microscopy. The results show that the response of human malignant melanoma cells to neutron irradiation is both cell line dependent and dose dependent, and that in any given cell line, some cells are more resistant to irradiation than others, thus demonstrating heterogeneity in respect to radiosensitivity. Cells repopulating MM96 flasks after irradiation were morphologically similar to the cells of origin whereas in MM418 flasks cells differentiated into five morphologically distinct subgroups and showed increased melanization. The results also show that radiation causes distinctive morphological patterns of damage although ultrastructural changes unique to the high LET particles released from boron 10 neutron capture are yet to be identified.

Investigating morphological awareness and the processing of transparent and opaque words in adults with low literacy skills and in skilled readers

PubMed Central

To, Nancy L.; Tighe, Elizabeth L.; Binder, Katherine S.

2015-01-01

For adults with low literacy skills, the role of phonology in reading has been fairly well researched, but less is known about the role of morphology in reading. We investigated the contribution of morphological awareness to word reading and reading comprehension and found that for adults with low literacy skills and skilled readers, morphological awareness explained unique variance in word reading and reading comprehension. In addition, we investigated the effects of orthographic and phonological opacity in morphological processing. Results indicated that adults with low literacy skills were more impaired than skilled readers on items containing phonological changes but were spared on items involving orthographic changes. These results are consistent with previous findings of adults with low literacy skills reliance on orthographic codes. Educational implications are discussed. PMID:27158173

Fractal branching organizations of Ediacaran rangeomorph fronds reveal a lost Proterozoic body plan.

PubMed

Hoyal Cuthill, Jennifer F; Conway Morris, Simon

2014-09-09

The branching morphology of Ediacaran rangeomorph fronds has no exact counterpart in other complex macroorganisms. As such, these fossils pose major questions as to growth patterns, functional morphology, modes of feeding, and adaptive optimality. Here, using parametric Lindenmayer systems, a formal model of rangeomorph morphologies reveals a fractal body plan characterized by self-similar, axial, apical, alternate branching. Consequent morphological reconstruction for 11 taxa demonstrates an adaptive radiation based on 3D space-filling strategies. The fractal body plan of rangeomorphs is shown to maximize surface area, consistent with diffusive nutrient uptake from the water column (osmotrophy). The enigmas of rangeomorph morphology, evolution, and extinction are resolved by the realization that they were adaptively optimized for unique ecological and geochemical conditions in the late Proterozoic. Changes in ocean conditions associated with the Cambrian explosion sealed their fate.

The thorax morphology of Epiophlebia (Insecta: Odonata) nymphs--including remarks on ontogenesis and evolution.

PubMed

Büsse, Sebastian; Helmker, Benjamin; Hörnschemeyer, Thomas

2015-08-06

The species of Epiophlebia are unique among the recent Odonata in showing a mixture of morphological characters of dragonflies (Anisoptera) and damselflies (Zygoptera). The status of the four described extant species of Epiophlebia is disputable from a genetic as well as from a morphological point of view. Here we present an analysis of the thoracic musculature of different nymphal instars of Epiophlebia laidlawi and Epiophlebia superstes to elucidate their morphology and ontogenetic development. In total, 75 muscles have been identified in the thorax of Epiophlebia. This represents the highest number of thoracic muscles ever found in any odonate. It includes six muscles that are reported for the first time for Odonata, and three of these are even new for Pterygota. In total, our results indicate that Epiophlebia has the most ancestral thoracic morphology among Odonata.

Effets de la pollution de l’air sur la santé

PubMed Central

Abelsohn, Alan; Stieb, Dave M.

2011-01-01

Résumé Objectif Faire connaître aux médecins de famille les effets de la pollution atmosphérique sur la santé et indiquer quels conseils donner aux patients vulnérables pour qu’ils soient moins exposés. Sources de l’information On a consulté MEDLINE à l’aide des termes relatifs à la pollution atmosphérique et à ses effets indésirables. On a révisé les articles en anglais publiés entre janvier 2008 et décembre 2009. La plupart des études contenaient des preuves de niveau II. Principal message Au Canada, la pollution de l’air extérieur cause une morbidité et une mortalité importantes. Elle peut affecter le système respiratoire (exacerbation de l’asthme et de la maladie pulmonaire obstructive chronique) et le système cardiovasculaire (déclencher l’arythmie, l’insuffisance cardiaque et les AVC). La cote air santé (CAS) est un nouvel outil de communication mis au point par Santé Canada et Environnement Canada qui indique sur une échelle de 1 à 10, le risque pour la santé causé par la pollution atmosphérique. La CAS est largement diffusée dans les médias et cet outil pourrait être utile au médecin de famille pour inciter les patients à haut risque (comme ceux qui souffrent d’asthme, de maladie pulmonaire obstructive chronique ou d’insuffisance cardiaque) à réduire leur exposition à la pollution atmosphérique. Conclusion Le médecin de famille peut se servir de la CAS et de ses messages sur la santé pour enseigner aux asthmatiques et aux autres patients à risque élevé la façon de réduire les risques pour la santé causés par la pollution atmosphérique.

Le rôle du soutien parental dans la relation entre la victimisation homophobe, l’homophobie intériorisée et la détresse psychologique chez les jeunes de minorités sexuelles (JMS) : une approche de médiation modérée

PubMed Central

Bergeron, Félix-Antoine; Blais, Martin; Hébert, Martine

2016-01-01

Résumé Cet article explore le rôle modérateur du soutien parental dans les relations entre la victimisation homophobe, l’homophobie intériorisée et la détresse psychologique chez des jeunes de minorités sexuelles (JMS), que l’on dit aussi lesbiennes, gais, bisexuels ou en questionnement. Il vise à 1) documenter la prévalence des différentes formes de victimisation homophobe vécue par les JMS, et ce, selon le genre et l’âge et 2) à explorer l’effet modérateur du soutien parental dans la relation entre la victimisation homophobe, l’homophobie intériorisée et la détresse psychologique. Un échantillon de 228 JMS âgés de 14 à 22 ans, non exclusivement hétérosexuels, recrutés en milieu communautaire dans le cadre de l’enquête sur le Parcours Amoureux des Jeunes (PAJ) du Québec a été analysé. L’impact de la victimisation homophobe, du soutien parental, de l’homophobie intériorisée sur la détresse psychologique est exploré par un modèle de régression linéaire avec effets de médiation modérée. Le rôle modérateur du soutien parental est confirmé dans la relation entre la victimisation homophobe et la détresse psychologique. Ces variables peuvent constituer des leviers pour prévenir les effets négatifs des préjudices homophobes sur la santé mentale des JMS. PMID:26966851

Etude thermo-hydraulique de l'ecoulement du moderateur dans le reacteur CANDU-6

NASA Astrophysics Data System (ADS)

Mehdi Zadeh, Foad

Etant donne la taille (6,0 m x 7,6 m) ainsi que le domaine multiplement connexe qui caracterisent la cuve des reacteurs CANDU-6 (380 canaux dans la cuve), la physique qui gouverne le comportement du fluide moderateur est encore mal connue de nos jours. L'echantillonnage de donnees dans un reacteur en fonction necessite d'apporter des changements a la configuration de la cuve du reacteur afin d'y inserer des sondes. De plus, la presence d'une zone intense de radiations empeche l'utilisation des capteurs courants d'echantillonnage. En consequence, l'ecoulement du moderateur doit necessairement etre etudie a l'aide d'un modele experimental ou d'un modele numerique. Pour ce qui est du modele experimental, la fabrication et la mise en fonction de telles installations coutent tres cher. De plus, les parametres de la mise a l'echelle du systeme pour fabriquer un modele experimental a l'echelle reduite sont en contradiction. En consequence, la modelisation numerique reste une alternative importante. Actuellement, l'industrie nucleaire utilise une approche numerique, dite de milieu poreux, qui approxime le domaine par un milieu continu ou le reseau des tubes est remplace par des resistances hydrauliques distribuees. Ce modele est capable de decrire les phenomenes macroscopiques de l'ecoulement, mais ne tient pas compte des effets locaux ayant un impact sur l'ecoulement global, tel que les distributions de temperatures et de vitesses a proximite des tubes ainsi que des instabilites hydrodynamiques. Dans le contexte de la surete nucleaire, on s'interesse aux effets locaux autour des tubes de calandre. En effet, des simulations faites par cette approche predisent que l'ecoulement peut prendre plusieurs configurations hydrodynamiques dont, pour certaines, l'ecoulement montre un comportement asymetrique au sein de la cuve. Ceci peut provoquer une ebullition du moderateur sur la paroi des canaux. Dans de telles conditions, le coefficient de reactivite peut varier de maniere importante, se traduisant par l'accroissement de la puissance du reacteur. Ceci peut avoir des consequences majeures pour la surete nucleaire. Une modelisation CFD (Computational Fluid Dynamics) detaillee tenant compte des effets locaux s'avere donc necessaire. Le but de ce travail de recherche est de modeliser le comportement complexe de l'ecoulement du moderateur au sein de la cuve d'un reacteur nucleaire CANDU-6, notamment a proximite des tubes de calandre. Ces simulations servent a identifier les configurations possibles de l'ecoulement dans la calandre. Cette etude consiste ainsi a formuler des bases theoriques a l'origine des instabilites macroscopiques du moderateur, c.-a-d. des mouvements asymetriques qui peuvent provoquer l'ebullition du moderateur. Le defi du projet est de determiner l'impact de ces configurations de l'ecoulement sur la reactivite du reacteur CANDU-6.

Proprietes ionochromes et photochromes de derives du polythiophene

NASA Astrophysics Data System (ADS)

Levesque, Isabelle

La synthese et la caracterisation de derives regioreguliers du polythiophene ont ete effectuees en solution et sur des films minces. La spectroscopie UV-visible de ces derives a permis de constater qu'ils peuvent posseder des proprietes chromiques particulieres selon le stimulus auquel ils sont soumis. Par exemple, une augmentation de la temperature permet en effet aux polymeres de passer d'une couleur violette a jaune, et ce, a l'etat solide aussi bien qu'en solution. Ces proprietes chromiques semblent regies par une transition conformationnelle (plane a non-plane) de la chaine principale. Ce travail avait pour but de mieux comprendre l'influence de l'organisation des chaines laterales sur les transitions chromiques. Deux derives synthetises possedant des chaines laterales sensibles aux cations alcalins se sont averes etre ionochromes en plus d'etre thermochromes. Il s'agit d'un polymere comportant des chaines laterales de type oligo(oxyethylene) et d'un autre comportant un groupement ether couronne specifique aux ions lithium. Les effets chromiques observes sont expliques par des interactions non-covalentes des cations avec les atomes d'oxygene des chaines laterales dans le cas du premier polymere, et par l'insertion de l'ion Li + dans la cavite de l'ether couronne dans le cas du second polymere. Ces interactions semblent provoquer une diminution de l'organisation induisant ainsi une torsion de la chaine principale. Les deux polymeres semblent specifiques a certains cations et pourraient donc servir comme detecteurs optiques. La specificite aux ions Li+ du second polymere pourrait aussi permettre la conduction ionique, en plus de la conductivite electronique caracteristique des polythiophenes, ce qui pourrait s'averer utile dans le cas de batteries legeres entierement faites de polymeres et de sels de lithium. D'autres derives comportant des chaines laterales de type azobenzene se sont averes etre photochromes en plus d'etre thermochromes. Le groupement lateral a la possibilite de changer de configuration de la forme trans a la forme cis lorsqu'il est soumis a une irradiation dans le domaine de l'ultraviolet ce qui provoque, selon toute evidence, un effet marque sur l'organisation des chaines laterales. Cela induit alors une torsion de la chaine principale thiophene entrainant une diminution de conjugaison marquee. Ces effets peuvent etre exploites entre autres dans l'ecriture optique. Il s'est avere que le polymere irradie peu conjugue peut etre force a retourner a son etat initial conjugue tres rapidement par un traitement electrochimique simple. En conclusion, on a pu prouver qu'une modification dans l'organisation des chaines laterales par un stimulus exterieur affecte considerablement la conformation de la chaine principale. Cela porte a croire que les chaines laterales stabilisent une conformation particuliere des polythiophenes.

Hypothetical Hyperion

NASA Astrophysics Data System (ADS)

Howard, A. D.; Moore, J. M.; Schenk, P. M.

2011-03-01

A simulation model of Hyperion's surface includes impact cratering, weathering, and mass wasting. The unique "swiss cheese" morphology is due to the non-retention on the surface of most of the impact debris and low crater rim heights.

Taking Up Space: Museum Exploration in the Twenty-First Century

ERIC Educational Resources Information Center

Sutton, Tiffany

2007-01-01

Museums have become a crucible for questions of the role that traditional art and art history should play in contemporary art. Friedrich Nietzsche argued in the nineteenth century that museums can be no more than mausoleums for effete (fine) art. Over the course of the twentieth century, however, curators dispelled such blanket pessimism by…

Issues and Prospects of Effetive Implementation of New Secondary School Curriculum in Nigeria

ERIC Educational Resources Information Center

Ahmadi, Ali A.; Lukman, Ajibola A.

2015-01-01

This paper digs into the issues surrounding effective implementation of new secondary school curriculum in Nigeria. This is based on the feeling that 21st century education is characterized with a dramatic technological revolution. The paper therefore portrays education in the 21st century as a total departure from the factory-model education of…

Optics of a Double Focussing Magnetic Sector by Fringe Effect; OPTIQUE D'UN SECTEUR MAGNETIQUE A DOUBLE FOCALISATION PAR EFFET DE FRANCES

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

Krafft, J.

1960-01-01

A general study is made of the optical elements of a double-fccusing magnetic sector by the fringe effect, with a view to its application to the monochromation of the proton, deuteron, or triton beam of the 1.4 Mev accelerator. (auth)

Investigations into the Power MOSFET SEGR Phenomenon and its Physical Mechanism

NASA Technical Reports Server (NTRS)

Swift, G. M.; Edmonds, L. E.; Miyahira, T.; Nichols, D. K.; Johnston, A. H.

1997-01-01

The state of understanding of the destructive SEGR event in power MOSFETs is relatively mature with large published efforts, both experimental and theoretical. However, gasps remain in the uderstanding of the phenomenon, including unexplained anomalies, emperical-only dependencies on some important device and incident ion physical parameters, and limited insight into latent effets.

Growth of ZnO nanorods on glass substrate deposited using dip coating method

NASA Astrophysics Data System (ADS)

Rani, Rozina Abdul; Ghafar, Safiah Ab; Zoolfakar, Ahmad Sabirin; Rusop, M.

2018-05-01

ZnO unique properties make it attractive for electronics and optoelectronics application. There are varieties synthesis of ZnO nanostructure but one of the best ways is by using dip coating method due to its simplicity, low cost and reliability. This research investigated the effect of precursor concentration on the morphology of ZnO nanorods using dip coating technique. ZnO nanorods is synthesized by using zinc nitrate as precursor and glass slide as substrate. The morphology of ZnO is characterized using Field Emission Scanning Electron Microscope (FESEM). By using different concentration of precursor, each outcome demonstrated diverse morphologies.

The thorax morphology of Epiophlebia (Insecta: Odonata) nymphs – including remarks on ontogenesis and evolution

PubMed Central

Büsse, Sebastian; Helmker, Benjamin; Hörnschemeyer, Thomas

2015-01-01

The species of Epiophlebia are unique among the recent Odonata in showing a mixture of morphological characters of dragonflies (Anisoptera) and damselflies (Zygoptera). The status of the four described extant species of Epiophlebia is disputable from a genetic as well as from a morphological point of view. Here we present an analysis of the thoracic musculature of different nymphal instars of Epiophlebia laidlawi and Epiophlebia superstes to elucidate their morphology and ontogenetic development. In total, 75 muscles have been identified in the thorax of Epiophlebia. This represents the highest number of thoracic muscles ever found in any odonate. It includes six muscles that are reported for the first time for Odonata, and three of these are even new for Pterygota. In total, our results indicate that Epiophlebia has the most ancestral thoracic morphology among Odonata. PMID:26246088

Plateau-Rayleigh Crystal Growth of Nanowire Heterostructures: Strain-Modified Surface Chemistry and Morphological Control in One, Two, and Three Dimensions.

PubMed

Day, Robert W; Mankin, Max N; Lieber, Charles M

2016-04-13

One-dimensional (1D) structures offer unique opportunities for materials synthesis since crystal phases and morphologies that are difficult or impossible to achieve in macroscopic crystals can be synthesized as 1D nanowires (NWs). Recently, we demonstrated one such phenomenon unique to growth on a 1D substrate, termed Plateau-Rayleigh (P-R) crystal growth, where periodic shells develop along a NW core to form diameter-modulated NW homostructures with tunable morphologies. Here we report a novel extension of the P-R crystal growth concept with the synthesis of heterostructures in which Ge (Si) is deposited on Si (Ge) 1D cores to generate complex NW morphologies in 1, 2, or 3D. Depositing Ge on 50 nm Si cores with a constant GeH4 pressure yields a single set of periodic shells, while sequential variation of GeH4 pressure can yield multimodulated 1D NWs with two distinct sets of shell periodicities. P-R crystal growth on 30 nm cores also produces 2D loop structures, where Ge (Si) shells lie primarily on the outside (inside) of a highly curved Si (Ge) core. Systematic investigation of shell morphology as a function of growth time indicates that Ge shells grow in length along positive curvature Si cores faster than along straight Si cores by an order of magnitude. Short Ge deposition times reveal that shells develop on opposite sides of 50 and 100 nm Si cores to form straight 1D morphologies but that shells develop on the same side of 20 nm cores to produce 2D loop and 3D spring structures. These results suggest that strain mediates the formation of 2 and 3D morphologies by altering the NW's surface chemistry and that surface diffusion of heteroatoms on flexible freestanding 1D substrates can facilitate this strain-mediated mechanism.

Mineralogy of Huygens Basin, Mars: A Transect of Noachian Highlands Crust

NASA Astrophysics Data System (ADS)

Seelos, K. D.; Ackiss, S. E.; Seelos, F. P.; McBeck, J. A.; Buczkowski, D. L.; Hash, C. D.; Viviano, C. E.; Murchie, S. L.

2018-06-01

Huygens crater represents a unique probe of the Noachain crust in the Hellas rim region. We have identified four mineralogic units within a morphologic context to understand the ancient martian highlands.

The Training of Morphological Decomposition in Word Processing and Its Effects on Literacy Skills.

PubMed

Bar-Kochva, Irit; Hasselhorn, Marcus

2017-01-01

This study set out to examine the effects of a morpheme-based training on reading and spelling in fifth and sixth graders ( N = 47), who present poor literacy skills and speak German as a second language. A computerized training, consisting of a visual lexical decision task (comprising 2,880 items, presented in 12 sessions), was designed to encourage fast morphological analysis in word processing. The children were divided between two groups: the one underwent a morpheme-based training, in which word-stems of inflections and derivations were presented for a limited duration, while their pre- and suffixes remained on screen until response. Another group received a control training consisting of the same task, except that the duration of presentation of a non-morphological unit was restricted. In a Word Disruption Task, participants read words under three conditions: morphological separation (with symbols separating between the words' morphemes), non-morphological separation (with symbols separating between non-morphological units of words), and no-separation (with symbols presented at the beginning and end of each word). The group receiving the morpheme-based program improved more than the control group in terms of word reading fluency in the morphological condition. The former group also presented similar word reading fluency after training in the morphological condition and in the no-separation condition, thereby suggesting that the morpheme-based training contributed to the integration of morphological decomposition into the process of word recognition. At the same time, both groups similarly improved in other measures of word reading fluency. With regard to spelling, the morpheme-based training group showed a larger improvement than the control group in spelling of trained items, and a unique improvement in spelling of untrained items (untrained word-stems integrated into trained pre- and suffixes). The results further suggest some contribution of the morpheme-based training to performance in a standardized spelling task. The morpheme-based training did not, however, show any unique effect on comprehension. These results suggest that the morpheme-based training is effective in enhancing some basic literacy skill in the population examined, i.e., morphological analysis in word processing and the access to orthographic representations in spelling, with no specific effects on reading fluency and comprehension.

The Training of Morphological Decomposition in Word Processing and Its Effects on Literacy Skills

PubMed Central

Bar-Kochva, Irit; Hasselhorn, Marcus

2017-01-01

This study set out to examine the effects of a morpheme-based training on reading and spelling in fifth and sixth graders (N = 47), who present poor literacy skills and speak German as a second language. A computerized training, consisting of a visual lexical decision task (comprising 2,880 items, presented in 12 sessions), was designed to encourage fast morphological analysis in word processing. The children were divided between two groups: the one underwent a morpheme-based training, in which word-stems of inflections and derivations were presented for a limited duration, while their pre- and suffixes remained on screen until response. Another group received a control training consisting of the same task, except that the duration of presentation of a non-morphological unit was restricted. In a Word Disruption Task, participants read words under three conditions: morphological separation (with symbols separating between the words’ morphemes), non-morphological separation (with symbols separating between non-morphological units of words), and no-separation (with symbols presented at the beginning and end of each word). The group receiving the morpheme-based program improved more than the control group in terms of word reading fluency in the morphological condition. The former group also presented similar word reading fluency after training in the morphological condition and in the no-separation condition, thereby suggesting that the morpheme-based training contributed to the integration of morphological decomposition into the process of word recognition. At the same time, both groups similarly improved in other measures of word reading fluency. With regard to spelling, the morpheme-based training group showed a larger improvement than the control group in spelling of trained items, and a unique improvement in spelling of untrained items (untrained word-stems integrated into trained pre- and suffixes). The results further suggest some contribution of the morpheme-based training to performance in a standardized spelling task. The morpheme-based training did not, however, show any unique effect on comprehension. These results suggest that the morpheme-based training is effective in enhancing some basic literacy skill in the population examined, i.e., morphological analysis in word processing and the access to orthographic representations in spelling, with no specific effects on reading fluency and comprehension. PMID:29163245

Implant bone integration importance in forensic identification.

PubMed

De Angelis, Danilo; Cattaneo, Cristina

2015-03-01

Odontological identification consists of the comparison of antemortem dental information regarding a missing person with postmortem data from an unidentified corpse or human remains. Usually, the comparison concerns morphologic features that the operator chooses among all the visible characteristics because of inter-individual uniqueness; for this reason, implants can be of enormous assistance. A case concerning the recovery of a burnt oral implant, connected to a bone fragment, among 2780 charred bone fragments, suspected to have belonged to a victim of homicide, is presented to demonstrate that dental implants and their site of bone integration represent a very precious element for personal forensic identification. Because of their morphological invariability in time and because of their morphologic uniqueness, they were used as evidence to associate unidentified human charred remains to a missing person where DNA analysis failed to do so. The case illustrates the fundamental contribution, not yet described in literature, given by the clinical aspects of tooth replacement with dental implants to a forensic discipline. Clinical practitioners should therefore be aware of the great importance of their work and of dental records in a forensic identification scenario. © 2014 American Academy of Forensic Sciences.

Mechanical instability driven self-assembly and architecturing of 2D materials

NASA Astrophysics Data System (ADS)

Cai Wang, Michael; Leem, Juyoung; Kang, Pilgyu; Choi, Jonghyun; Knapp, Peter; Yong, Keong; Nam, SungWoo

2017-06-01

Two-dimensional (2D) materials have been well studied for their diverse and impressive properties and superlative mechanical strength. Their atomic thinness and weak van der Waals interaction, while fascinating and unique, dictate their tendency to exhibit out of plane morphologies such as bending, buckling, folding, rippling, scrolling, and wrinkling, etc. In this review, we discuss the mechanisms behind these instability driven morphologies and the resultant phenomena that arise. We then survey methods to manipulate them especially in a scalable manner, and elucidate some interesting applications uniquely enabled by these structures. Contrary to conventional wisdom, the deterministic control of these features has great implications for the local and overall material properties due to heterogeneous distribution of stresses and strains. The introduction of deformable and shape memory substrates especially allow for facile and large scale synthesis of various types of out of plane morphologies. We show that a variety of exciting phenomena and applications arise, including tunable surfaces and coatings, robust devices and electronics, adaptive optoelectronics, material toughening, energy storage, and chemical sensing. This new perspective on these otherwise nuisance thin-film phenomena enable new tools for future materials discovery, design, and synthesis with the ever growing library of 2D atomically thin materials.

Development of the pseudothumb in frogs

PubMed Central

Tokita, Masayoshi; Iwai, Noriko

2010-01-01

Frogs have highly conserved hand and foot morphology, possessing four fingers and five toes. As an exception, two Japanese ranid frog species, the Otton frog Babina subaspera and the dagger frog Babina holsti, possess a unique thumb-like structure (the pseudothumb) in the forelimb, giving an appearance of a total of five fingers on the hand. To obtain insights into the developmental mechanisms that generate this novel character, we investigated the hand morphogenesis of the Otton frog. The unique morphological pattern of the pseudothumb was already established in juveniles. Surprisingly, the bud-like structure, which is similar to the area of inductive activity (e.g. feather buds in birds and the carapacial ridge in turtles), was detected over the site where the future prepollex develops in larvae. By contrast, this bud-like structure was not found in larvae of other ranid species. We discuss possible scenarios that would favour the evolution of this very unusual trait in frogs. PMID:20147308

Bacterial cytoskeleton and implications for new antibiotic targets.

PubMed

Wang, Huan; Xie, Longxiang; Luo, Hongping; Xie, Jianping

2016-01-01

Traditionally eukaryotes exclusive cytoskeleton has been found in bacteria and other prokaryotes. FtsZ, MreB and CreS are bacterial counterpart of eukaryotic tubulin, actin filaments and intermediate filaments, respectively. FtsZ can assemble to a Z-ring at the cell division site, regulate bacterial cell division; MreB can form helical structure, and involve in maintaining cell shape, regulating chromosome segregation; CreS, found in Caulobacter crescentus (C. crescentus), can form curve or helical filaments in intracellular membrane. CreS is crucial for cell morphology maintenance. There are also some prokaryotic unique cytoskeleton components playing crucial roles in cell division, chromosome segregation and cell morphology. The cytoskeleton components of Mycobacterium tuberculosis (M. tuberculosis), together with their dynamics during exposure to antibiotics are summarized in this article to provide insights into the unique organization of this formidable pathogen and druggable targets for new antibiotics.

U-Pb geochronologic constraints on the origin of a unique monazite- xenotime gneiss, Hudson Highlands, New York

USGS Publications Warehouse

Aleinikoff, J.N.; Grauch, R.I.

1990-01-01

A unique rock composed almost entirely of equal proportions of monazite and xenotime occurs as a small, lenticular body (2 ?? 0.5 ?? 0.3 m) in association with paragneiss, migmatite, and Canada Hill Granite in an outcrop in the Hudson Highlands of southeastern New York. The paragneiss contains detrital zircon (207Pb/206Pb ages of 1150-1460 Ma), monazite, and xenotime (both dated at about 1000 Ma). Zircons from the monazite-xenotime gneiss contain dark, rounded cores and clear rims, a morphology suggestive of derivation from the paragneiss, with subsequent metamorphic overgrowth. We conclude, based on results from xenotime and zircon rims, that the monazite-xenotime gneiss formed at about 985 Ma. Based on zircon morphology and age relations within the outcrop, we prefer a metasomatic origin over other possibilities such as a paleo-placer or anatectic restite. -from Authors

Osseointegration of Plateau Root Form Implants: Unique Healing Pathway Leading to Haversian-Like Long-Term Morphology.

PubMed

Coelho, Paulo G; Suzuki, Marcelo; Marin, Charles; Granato, Rodrigo; Gil, Luis F; Tovar, Nick; Jimbo, Ryo; Neiva, Rodrigo; Bonfante, Estevam A

2015-01-01

Endosteal dental implants have been utilized as anchors for dental and orthopedic rehabilitations for decades with one of the highest treatment success rates in medicine. Such success is due to the phenomenon of osseointegration where after the implant surgical placement, bone healing results into an intimate contact between bone and implant surface. While osseointegration is an established phenomenon, the route which osseointegration occurs around endosteal implants is related to various implant design factors including surgical instrumentation and implant macro, micro, and nanometer scale geometry. In an implant system where void spaces (healing chambers) are present between the implant and bone immediately after placement, its inherent bone healing pathway results in unique opportunities to accelerate the osseointegration phenomenon at the short-term and its maintenance on the long-term through a haversian-like bone morphology and mechanical properties.

Did Lizards Follow Unique Pathways in Sex Chromosome Evolution?

PubMed Central

Gleeson, Dianne; Georges, Arthur

2018-01-01

Reptiles show remarkable diversity in modes of reproduction and sex determination, including high variation in the morphology of sex chromosomes, ranging from homomorphic to highly heteromorphic. Additionally, the co-existence of genotypic sex determination (GSD) and temperature-dependent sex determination (TSD) within and among sister clades makes this group an attractive model to study and understand the evolution of sex chromosomes. This is particularly so with Lizards (Order Squamata) which, among reptiles, show extraordinary morphological diversity. They also show no particular pattern of sex chromosome degeneration of the kind observed in mammals, birds and or even in snakes. We therefore speculate that sex determination sensu sex chromosome evolution is labile and rapid and largely follows independent trajectories within lizards. Here, we review the current knowledge on the evolution of sex chromosomes in lizards and discuss how sex chromosome evolution within that group differs from other amniote taxa, facilitating unique evolutionary pathways. PMID:29751579

A new dwarf crayfish (Decapoda: Cambaridae) from floodplain swamps in central Alabama.

PubMed

Schuster, Guenter A; Kendrick, Michael R

2017-03-05

Cambarellus (Pandicambarus) rotatus, new species, is a dwarf crayfish from floodplain swamps in the Tombigbee and Black Warrior river drainages of Greene, Hale, and Marengo counties, Alabama. The new species is morphologically most similar to Cambarellus (Pandicambarus) lesliei. They differ in a several morphological characters. Cambarellus rotatus, new species, has gonopods that are rotated mesially so that the terminal elements oppose each other, and they have a short C-shaped sperm groove. These are unique features among known species of Cambarellus.

The Cultivation of Ivy. A Saga of the College in America.

ERIC Educational Resources Information Center

Thelin, John R

The popular image of the Ivy League is one of a slightly awesome bastion of the well-born, well-bred, and soon-to-be-powerful or, less charitably, a haven for "the effete, unAmerican, and hopelessly bookish." This pervasive idea of collegiate personality is analyzed, tracing the evolution of the Ivy League from an incongruous array of…

Human Benchmarking of Expert Systems. Literature Review

DTIC Science & Technology

1990-01-01

effetiveness of the development procedures used in order to predict whether the aplication of similar approaches will likely have effective and...they used in their learning and problem solving. We will describe these approaches later. Reasoning. Reasoning usually includes inference. Because to ... in the software engineering process. For example, existing approaches to software evaluation in the military are based on a model of conventional

Electronic Structure and Morphology of Graphene Layers on SiC

NASA Astrophysics Data System (ADS)

Ohta, Taisuke

2008-03-01

Recent years have witnessed the discovery and the unique electronic properties of graphene, a sheet of carbon atoms arranged in a honeycomb lattice. The unique linear dispersion relation of charge carriers near the Fermi level (``Dirac Fermions'') lead to exciting transport properties, such as an unusual quantum Hall effect, and have aroused scientific and technological interests. On the way towards graphene-based electronics, a knowledge of the electronic band structure and the morphology of epitaxial graphene films on silicon carbide substrates is imperative. We have studied the evolution of the occupied band structure and the morphology of graphene layers on silicon carbide by systematically increasing the layer thickness. Using angle-resolved photoemission spectroscopy (ARPES), we examine this unique 2D system in its development from single layer to multilayers, by characteristic changes in the π band, the highest occupied state, and the dispersion relation in the out-of-plane electron wave vector in particular. The evolution of the film morphology is evaluated by the combination of low-energy electron microscopy and ARPES. By exploiting the sensitivity of graphene's electronic states to the charge carrier concentration, changes in the on-site Coulomb potential leading to a change of π and π* bands can be examined using ARPES. We demonstrate that, in a graphene bilayer, the gap between π and π* bands can be controlled by selectively adjusting relative carrier concentrations, which suggests a possible application of the graphene bilayer for switching functions in electronic devices. This work was done in collaboration with A. Bostwick, J. L. McChesney, and E. Rotenberg at Advanced Light Source, Lawrence Berkeley National Laboratory, K. Horn at Fritz-Haber-Institut, K. V. Emtsev and Th. Seyller at Lehrstuhl für Technische Physik, Universität Erlangen-Nürnberg, and F. El Gabaly and A. K. Schmid at National Center for Electron Microscopy, Lawrence Berkeley National Laboratory.

Symetrie en energie des spectres de l'onde de densite de charge dans le 2-hydrogene seleniure de niobium

NASA Astrophysics Data System (ADS)

Behmand, Behnaz

Les mecanismes qui menent a la supraconductivite dans les supraconducteurs a haute temperature critique sont encore aujourd'hui mal compris contrairement a ceux dans les supraconducteurs conventionnels. Dans les hauts-Tc, certaines modulations de la densite d'etats electroniques coexistant avec la phase supraconductrice ont ete observees, ce qui engendre des questionnements sur leur role dans la supraconductivite. En fait, plusieurs types de modulation de la densite d'etats electroniques existent, comme par exemple l'onde de densite de charge et l'onde de densite de paires. Ces deux modulations, d'origines differentes et mesurables avec la technique de spectroscopie par effet tunnel, peuvent etre differenciees avec une etude de leur symetrie. Ce memoire consistera donc a presenter l'etude de la symetrie de l'onde de densite de charge dans le 2H-NbSe2 qui est presente dans la phase supraconductrice a 300 mK. Par contre, certaines difficultes liees au principe de mesure, soit l'effet de normalisation, nuisent a l'identification de cette symetrie. La methode, pour contourner ce probleme sera alors l'element clef de ce travail.

Accident D’Electrisation et Hemorragie Cerebro-Meningee : A Propos D’une Observation

PubMed Central

Chaibdraa, A.; Medjellakh, M.S.; Saouli, A.; Bentakouk, M.C.

2008-01-01

Summary L'électrisation est un évènement accidentel qui diffère des autres pathologies occasionnant des brûlures graves, à cause de ses spécificités qui traduisent d'une part la destruction du revêtement cutané, mais également les effets directs ou indirects du courant électrique sur tout tissu de l'organisme rencontré lors de son passage, en particulier le tissu nerveux. Les manifestations neurologiques centrales sont nombreuses, en relation avec les effets de l'électricité sur le parenchyme cérébral ou une lésion associée à l'électrisation. Nous rapportons l'observation d'une hémorragie cérébro-meningée survenant au 3ème jour d'une électrisation grave. Cette complication est bien documentée dans la littérature traitant des accidents d'électrisation post-foudroiement. N'ayant pas rencontré de cas similaire publié lors des accidents dus au courant industriel, nous présentons cette observation, qui soulève le problème du mécanisme physiopathologique de survenue, difficile à trancher. PMID:21991125

Nouvelles approches en theorie du champ moyen dynamique: le cas du pouvoir thermoelectrique et celui de l'effet orbital d'un champ magnetique

NASA Astrophysics Data System (ADS)

Arsenault, Louis-Francois

Les applications reliees a la generation d'energie motivent la recherche de materiaux ayant un fort pouvoir thermoelectrique (S). De plus, S nous renseigne sur certaines proprietes fondamentales des materiaux, comme, par exemple, la transition entre l'etat coherent et incoherent des quasi-particules lorsque la temperature augmente. Empiriquement, la presence de fortes interactions electron-electron peut mener a un pouvoir thermoelectrique geant. Nous avons donc etudie le modele le plus simple qui tient compte de ces fortes interactions, le modele de Hubbard. La theorie du champ moyen dynamique (DMFT) est tout indiquee dans ce cas. Nous nous sommes concentres sur un systeme tridimensionnel (3d) cubique a face centree (fcc), et ce, pour plusieurs raisons. A) Ce type de cristal est tres commun dans la nature. B) La DMFT donne de tres bons resultats en 3d et donc ce choix sert aussi de preuve de principe de la methode. C) Finalement, a cause de la frustration electronique intrinseque au fcc, celui-ci ne presente pas de symetrie particule-trou, ce qui est tres favorable a l'apparition d'une grande valeur de S. Ce travail demontre que lorsque le materiau est un isolant a demi-remplissage a cause des fortes interactions (isolant de Mott), il est possible d'obtenir de grands pouvoirs thermoelectriques en le dopant legerement. C'est un resultat pratique important. Du point de vue methodologique, nous avons montre comment la limite de frequence infinie de S et l'approche dite de Kelvin, qui considere la limite de frequence nulle avant la limite thermodynamique pour S, donnent des estimations fiables de la vraie limite continue (DC) dans les domaines de temperature appropriee. Ces deux approches facilitent grandement les calculs en court-circuit ant la necessite de recourir a de problematiques prolongements analytiques. Nous avons trouve que la methode de calcul a frequence infinie fonctionne bien lorsque les echelles d'energie sont relativement faibles. En d'autres termes, cette approche donne une bonne representation de S lorsque le systeme devient coherent. Les calculs montrent aussi que la formule Kelvin est precise lorsque la fonction spectrale des electrons devient incoherente, soit a plus haute temperature. Dans la limite Kelvin, S est essentiellement l'entropie par particule, tel que propose il y a longtemps. Nos resultats demontrent ainsi que la vision purement entropique de S est la bonne dans le regime incoherent, alors que dans le regime coherent, l'approche a frequence infinie est meilleure. Nous avons utilise une methode a la fine pointe, soit le Monte-Carlo quantique en temps continu pour resoudre la DMFT. Pour permettre une exploration rapide du diagramme de phase, nous avons du developper une nouvelle version de la methode des perturbations iterees pour qu'elle soit applicable aussi a forte interaction au-dela de la valeur critique de la transition de Mott. Un autre sujet a aussi ete aborde. L'effet orbital du champ magnetique dans les systemes electroniques fortement correles est une question tres importante et peu developpee. Cela est d'autant plus essentiel depuis la decouverte des oscillations quantiques dans les supraconducteurs a haute temperature (haut- Tc). Par desir de developper une methode la moins biaisee possible, nous avons derive la DMFT lorsqu'un champ se couplant a l'operateur energie cinetique par la substitution de Peierls est present. Ce type d'approche est necessaire pour comprendre entre autres l'effet de la physique de Mott sur des phenomenes tels que les oscillations quantiques. Nous avons obtenu un resultat tres important en demontrant rigoureusement que la relation d'auto-coherence de la DMFT et le systeme intermediaire d'impurete quantique restent les memes. L'effet du champ peut etre contenu dans la fonction de Green locale, ce qui constitue la grande difference avec le cas habituel. Ceci permet de continuer a utiliser les solutionneurs d'impuretes standards, qui sont de plus en plus puissants. Nous avons aussi developpe la methode pour le cas d'un empilement de plans bidimensionnels selon z, ce qui permet d'etudier l'effet orbital du champ dans des nanostructures et meme dans les materiaux massifs, si le nombre de plans est suffisant pour obtenir la limite tridimensionnelle. Mots cles : Pouvoir thermoelectrique, Theorie du Champ Moyen Dynamique, Modele de Hubbard, Effet orbital du champ magnetique, Electrons fortement correles, Materiaux quantiques, Theorie des perturbations iterees

Spatially restricted dental regeneration drives pufferfish beak development

PubMed Central

Thiery, Alexandre P.; Shono, Takanori; Kurokawa, Daisuke; Britz, Ralf; Johanson, Zerina

2017-01-01

Vertebrate dentitions are extraordinarily diverse in both morphology and regenerative capacity. The teleost order Tetraodontiformes exhibits an exceptional array of novel dental morphologies, epitomized by constrained beak-like dentitions in several families, i.e., porcupinefishes, three-toothed pufferfishes, ocean sunfishes, and pufferfishes. Modification of tooth replacement within these groups leads to the progressive accumulation of tooth generations, underlying the structure of their beaks. We focus on the dentition of the pufferfish (Tetraodontidae) because of its distinct dental morphology. This complex dentition develops as a result of (i) a reduction in the number of tooth positions from seven to one per quadrant during the transition from first to second tooth generations and (ii) a dramatic shift in tooth morphogenesis following the development of the first-generation teeth, leading to the elongation of dental units along the jaw. Gene expression and 1,1′-Dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI) lineage tracing reveal a putative dental epithelial progenitor niche, suggesting a highly conserved mechanism for tooth regeneration despite the development of a unique dentition. MicroCT analysis reveals restricted labial openings in the beak, through which the dental epithelium (lamina) invades the cavity of the highly mineralized beak. Reduction in the number of replacement tooth positions coincides with the development of only four labial openings in the pufferfish beak, restricting connection of the oral epithelium to the dental cavity. Our data suggest the spatial restriction of dental regeneration, coupled with the unique extension of the replacement dental units throughout the jaw, are primary contributors to the evolution and development of this unique beak-like dentition. PMID:28507130

"Corkscrew stenosis": defining and preventing a complication of percutaneous dilatational tracheostomy.

PubMed

Jacobs, Jordan V; Hill, David A; Petersen, Scott R; Bremner, Ross M; Sue, Richard D; Smith, Michael A

2013-03-01

The short-term safety of percutaneous dilatational tracheostomy has been widely demonstrated. However, less is known about their long-term complications. Through an illustrative case series, we present and define "corkscrew stenosis," a type of tracheal stenosis uniquely associated with percutaneous dilatational tracheostomy. Patients treated at our institution for tracheal stenosis after percutaneous dilatational tracheostomy were reviewed. Demographic data including gender, age, history of presentation, lesion morphology, imaging, and management was collected and evaluated. The pathology of the stenosis and the strategies for prevention are presented. From January, 2008 through December 2011, 11 patients had tracheal stenosis after percutaneous dilatational tracheostomy. The mean age was 54 ± 17 years and 55% were male. The stenotic lesions were characterized by a corkscrew morphology at the stoma site with a mean distance of 2.3 ± 0.8 cm from the vocal cords. Images of these lesions demonstrated disruption and fracture of the proximal tracheal cartilages and displacement of the anterior tracheal wall into the tracheal lumen. The majority of our patients required tracheal resection for definitive repair. We suggest that a unique form of tracheal stenosis can result from percutaneous dilatational tracheostomy. We observed corkscrew stenosis to be located proximally, associated with fractured tracheal rings, and morphologically appearing as interdigitation of these fractured rings. Recognizing corkscrew stenosis, its unique mechanism of formation, and technical means of prevention may be important in advancing the long-term safety of this procedure for critically ill patients who require prolonged ventilatory support. Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Three-dimensional echocardiography of congenital abnormalities of the left atrioventricular valve.

PubMed

Rice, Kathryn; Simpson, John

2015-03-01

Congenital abnormalities of the left atrioventricular (AV) valve are a significant diagnostic challenge. Traditionally, reliance has been placed on two-dimensional echocardiographic (2DE) imaging to guide recognition of the specific morphological features. Real-time 3DE can provide unique views of the left AV valve with the potential to improve understanding of valve morphology and function to facilitate surgical planning. This review illustrates the features of congenital abnormalities of the left AV valve assessed by 3DE. The similarities and differences in morphology between different lesions are described, both with respect to the valve itself and supporting chordal apparatus. The potential advantages as well as limitations of this technique in clinical practice are outlined.

Linear Depolarization of Lidar Returns by Aged Smoke Particles

NASA Technical Reports Server (NTRS)

Mishchenko, Michael I.; Dlugach, Janna M.; Liu, Li

2016-01-01

We use the numerically exact (superposition) T-matrix method to analyze recent measurements of the backscattering linear depolarization ratio (LDR) for a plume of aged smoke at lidar wavelengths ranging from 355 to 1064 nm. We show that the unique spectral dependence of the measured LDRs can be modeled, but only by assuming expressly nonspherical morphologies of smoke particles containing substantial amounts of nonabsorbing (or weakly absorbing) refractory materials such as sulfates. Our results demonstrate that spectral backscattering LDR measurements can be indicative of the presence of morphologically complex smoke particles, but additional (e.g., passive polarimetric or bistatic lidar) measurements may be required for a definitive characterization of the particle morphology and composition.

Phylogeny of Fish-Infecting Calyptospora species (Apicomplexa: Eimeriorina)

EPA Science Inventory

There are numerous species of apicomplexans that infect poikilothermic vertebrates such as fishes, and possess unique morphological features that provide insight into the evolution of this important phylum of parasites. Here the relationship of the fish-infecting Calyptospora spe...

Fibrillation auriculaire et activité physique

PubMed Central

Bosomworth, N. John

2015-01-01

Résumé Objectif Examiner les données probantes portant sur les effets de divers niveaux d’activité physique sur l’incidence de fibrillation auriculaire (FA) dans la population générale et chez les athlètes d’endurance. Sources des données Une recherche a initialement été menée sur PubMed à l’aide des titres MeSH ou des mots-de-texte anglais (avec descripteur de zone de recherche TIAB [title and abstract]) atrial fibrillation et exercise ou physical activity ou athlet* ou sport*, sans filtre additionnel. Le système GRADE (grading of recommendations, assessment, development, and evaluation) a été utilisé pour tirer les conclusions au sujet de la qualité et du niveau de preuve. Sélection des études Aucune étude d’intervention n’est ressortie de la recherche. Les études d’observation ont alors été jugées acceptables et, bien que des études prospectives de cohortes à long terme de plus grande envergure auraient été préférables, des essais cas-témoins ou transversaux ont aussi été inclus dans cette révision. Synthèse Les données disponibles laissent croire à un lien proportionnel à la dose entre l’exercice plus intense et l’incidence réduite de FA chez les femmes. Il en va de même pour les hommes dont le niveau d’activité physique est de faible à modéré. Chez les hommes seulement, l’activité intense est associée à un risque accru de FA et ce, dans la plupart des études, mais pas la totalité d’entre elles. Ce risque est modéré, le rapport de risque instantané étant de 1,29 dans l’une des études de meilleure qualité. Le risque de FA chez la plupart des personnes régulièrement actives est plus faible que le risque observé dans la population sédentaire appariée. Conclusion La fibrillation auriculaire est probablement moins fréquente à mesure que le niveau d’activité physique augmente, la relation dose-réponse étant démontrable. À toutes les intensités, l’exercice doit être encouragé pour ses effets sur le bien-être physique et la réduction de la mortalité. Chez les hommes qui pratiquent des activités vigoureuses, les effets bénéfiques sur la FA pourraient disparaître et le risque pourrait surpasser celui observé dans la population sédentaire; cependant les données probantes à cet effet ne sont ni robustes ni constantes. Ces hommes devraient être mis au courant de cette hausse modeste du risque s’ils choisissent de poursuivre leurs activités physiques vigoureuses.

Inorganic Nanoparticle Induced Morphological Transition for Confined Self-Assembly of Block Copolymers within Emulsion Droplets.

PubMed

Zhang, Yan; He, Yun; Yan, Nan; Zhu, Yutian; Hu, Yuexin

2017-09-07

Recently, it has been reported that the incorporation of functional inorganic nanoparticles (NPs) into the three-dimensional (3D) confined self-assembly of block copolymers (BCPs) creates the unique nanostructured hybrid composites, which can not only introduce new functions to BCPs but also induce some interesting morphological transitions of BCPs. In the current study, we systematically investigate the cooperative self-assembly of a series of size-controlled and surface chemistry-tunable gold nanoparticles (AuNPs) and polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) diblock copolymer within the emulsion droplets. The influences of the size, content, and surface chemistry of the AuNPs on the coassembled nanostructures as well as the spatial distribution of AuNPs in the hybrid particles are examined. It is found that the size and content of the AuNPs are related to the entropic interaction, while the surface chemistry of AuNPs is related to the enthalpic interaction, which can be utilized to tailor the self-assembled morphologies of block copolymer confined in the emulsion droplets. As the content of PS-coated AuNPs increases, the morphology of the resulting AuNPs/PS-b-P2VP hybrid particles changes from the pupa-like particles to the bud-like particles and then to the onion-like particles. However, a unique morphological transition from the pupa-like particles to the mushroom-like particles is observed as the content of P4VP-coated AuNPs increases. More interestingly, it is observed that the large AuNPs are expelled to the surface of the BCP particles to reduce the loss in the conformational entropy of the block segment, which can arrange into the strings of necklaces on the surfaces of the hybrid particles.

The Unique Dorsal Brood Pouch of Thermosbaenacea (Crustacea, Malacostraca) and Description of an Advanced Developmental Stage of Tulumella unidens from the Yucatan Peninsula (Mexico), with a Discussion of Mouth Part Homologies to Other Malacostraca

PubMed Central

Olesen, Jørgen; Boesgaard, Tom; Iliffe, Thomas M.

2015-01-01

The Thermosbaenacea, a small taxon of crustaceans inhabiting subterranean waters, are unique among malacostracans as they brood their offspring dorsally under the carapace. This habit is of evolutionary interest but the last detailed report on thermosbaenacean development is more than 40 years old. Here we provide new observations on an ovigerous female of Tulumella unidens with advanced developmental stages in its brood chamber collected from an anchialine cave at the Yucatan Peninsula, which is only the third report on developmental stages of Thermosbaenacea and the first for the genus Tulumella. Significant in a wider crustacean context, we report and discuss hitherto unexplored lobate structures inside the brood chamber of the female originating at the first (maxilliped) and second thoracic segments, which are most likely modified epipods, perhaps serving as gills. At the posterior margin of carapace of the female are rows of large spines preventing the developing stages from falling out. The external morphology of the advanced developmental stages is described in much detail, providing information on e.g., carapace formation and early limb morphology. Among the hitherto unknown structures in the advanced developmental stages provided by this study are the presence of an embryonic dorsal organ and rudimentary ‘naupliar processes’ of the second antennae. Since most hypotheses on crustacean (and malacostracan and peracaridan) relationship rest on external limb morphology, we use early limb bud morphology of Tulumella to better establish thermosbaenacean limb homologies to those of other crustaceans, which is a necessary basis for future morphology based phylogenetic considerations. PMID:25901753

The Unique Dorsal Brood Pouch of Thermosbaenacea (Crustacea, Malacostraca) and Description of an Advanced Developmental Stage of Tulumella unidens from the Yucatan Peninsula (Mexico), with a Discussion of Mouth Part Homologies to Other Malacostraca.

PubMed

Olesen, Jørgen; Boesgaard, Tom; Iliffe, Thomas M

2015-01-01

The Thermosbaenacea, a small taxon of crustaceans inhabiting subterranean waters, are unique among malacostracans as they brood their offspring dorsally under the carapace. This habit is of evolutionary interest but the last detailed report on thermosbaenacean development is more than 40 years old. Here we provide new observations on an ovigerous female of Tulumella unidens with advanced developmental stages in its brood chamber collected from an anchialine cave at the Yucatan Peninsula, which is only the third report on developmental stages of Thermosbaenacea and the first for the genus Tulumella. Significant in a wider crustacean context, we report and discuss hitherto unexplored lobate structures inside the brood chamber of the female originating at the first (maxilliped) and second thoracic segments, which are most likely modified epipods, perhaps serving as gills. At the posterior margin of carapace of the female are rows of large spines preventing the developing stages from falling out. The external morphology of the advanced developmental stages is described in much detail, providing information on e.g., carapace formation and early limb morphology. Among the hitherto unknown structures in the advanced developmental stages provided by this study are the presence of an embryonic dorsal organ and rudimentary 'naupliar processes' of the second antennae. Since most hypotheses on crustacean (and malacostracan and peracaridan) relationship rest on external limb morphology, we use early limb bud morphology of Tulumella to better establish thermosbaenacean limb homologies to those of other crustaceans, which is a necessary basis for future morphology based phylogenetic considerations.

Comparative morphology analysis of live blood platelets using scanning ion conductance and robotic dark-field microscopy.

PubMed

Kraus, Max-Joseph; Seifert, Jan; Strasser, Erwin F; Gawaz, Meinrad; Schäffer, Tilman E; Rheinlaender, Johannes

2016-09-01

Many conventional microscopy techniques for investigating platelet morphology such as electron or fluorescence microscopy require highly invasive treatment of the platelets such as fixation, drying and metal coating or staining. Here, we present two unique but entirely different microscopy techniques for direct morphology analysis of live, unstained platelets: scanning ion conductance microscopy (SICM) and robotic dark-field microscopy (RDM). We demonstrate that both techniques allow for a quantitative evaluation of the morphological features of live adherent platelets. We show that their morphology can be quantified by both techniques using the same geometric parameters and therefore can be directly compared. By imaging the same identical platelets subsequently with SICM and RDM, we found that area, perimeter and circularity of the platelets are directly correlated between SICM and dark-field microscopy (DM), while the fractal dimension (FD) differed between the two microscopy techniques. We show that SICM and RDM are both valuable tools for the ex vivo investigation of the morphology of live platelets, which might contribute to new insights into the physiological and pathophysiological role of platelet spreading.

Microenvironment Induced Spheroid to Sheeting Transition of Immortalized Human Keratinocytes (HaCaT) Cultured in Microbubbles Formed in Polydimethylsiloxane

PubMed Central

Chandrasekaran, Siddarth; Giang, Ut-Binh; King, Michael R.; DeLouise, Lisa A

2011-01-01

The in vivo cellular microenvironment is regulated by a complex interplay of soluble factors and signaling molecules secreted by cells and it plays a critical role in the growth and development of normal and diseased tissues. In vitro systems that can recapitulate the microenvironment at the cellular level are needed to investigate the influence of autocrine signaling and extracellular matrix effects on tissue homeostasis, regeneration, and disease development and progression. In this study we report the use of microbubble technology as a means to culture cells in a controlled microenvironment in which cells can influence their function through autocrine signaling. Microbubbles (MB) are small spherical cavities about 100–300 µm in diameter formed in hydrophobic polymer polydimethylsiloxane (PDMS) with ~60–100 µm circular openings and aspect ratio ~3.5. We demonstrate that the unique architecture of the microbubble compartment is advantaged for cell culture using HaCaT cells, an immortalized keratinocyte cell line. We observe that HaCaT cells, seeded in microbubbles (15–20 cells / MB) and cultured under standard conditions, adopt a compact 3-D spheroidal morphology. Within 2–3 days, the cells transition to a sheeting morphology. Through experimentation and simulation we show that this transition in morphology is due to the unique architecture of the microbubble compartment which enables cells to condition their local microenvironment. The small media volume per cell and the development of shallow concentration gradients allow factors secreted by the cells to rise to bioactive levels. The kinetics of the morphology transition depends on the number of cells seeded per microbubble; higher cell seeding induces a more rapid transition. HaCaT cells seeded onto PDMS cured in 96-well plates also form compact spheroids but they do not transition to a sheeting morphology even after several weeks of culture. The importance of soluble factor accumulation in driving this morphology transition in microbubbles is supported by the observation that spheroids do not form when cells - seeded into microbubbles or onto PDMS cured in 96 well plates - are cultured in media conditioned by HaCaT cells grown in standard tissue culture plate. We observed that the addition of TGF-β1 to the growth media induced cells to proliferate in a sheeting morphology from the onset both on PDMS cured in 96-well plates and in microbubbles. TGF-β1 is a morphogen known to regulate epithelial-to-mesenchymal transition (EMT). Studies of the role of Ca2+ concentration and changes in Ecadherin expression additionally support an EMT-like HaCaT morphology transition. These findings taken together validate the microbubble compartment as a unique cell culture platform that can potentially transform investigative studies in cell biology and in particular the tumor microenvironment. Targeting the tumor microenvironment is an emerging area of anti-cancer therapy. PMID:21724250

Wool shrinkproofing by chemical and ezymatic methods

USDA-ARS?s Scientific Manuscript database

The uniqueness of wool, its functionality, morphology, physical/ mechanical behavior, and aesthetics, continue to be topics for innovative research to improve properties and create novel products. The perennial problems of yellowness, discomfort in wear, and shrinkage have been addressed over time ...

Modeling the Relations Among Morphological Awareness Dimensions, Vocabulary Knowledge, and Reading Comprehension in Adult Basic Education Students

PubMed Central

Tighe, Elizabeth L.; Schatschneider, Christopher

2016-01-01

This study extended the findings of Tighe and Schatschneider (2015) by investigating the predictive utility of separate dimensions of morphological awareness as well as vocabulary knowledge to reading comprehension in adult basic education (ABE) students. We competed two- and three-factor structural equation models of reading comprehension. A three-factor model of real word morphological awareness, pseudoword morphological awareness, and vocabulary knowledge emerged as the best fit and accounted for 79% of the reading comprehension variance. The results indicated that the constructs contributed jointly to reading comprehension; however, vocabulary knowledge was the only potentially unique predictor (p = 0.052), accounting for an additional 5.6% of the variance. This study demonstrates the feasibility of applying a latent variable modeling approach to examine individual differences in the reading comprehension skills of ABE students. Further, this study replicates the findings of Tighe and Schatschneider (2015) on the importance of differentiating among dimensions of morphological awareness in this population. PMID:26869981

Indirect Reconstruction of Pore Morphology for Parametric Computational Characterization of Unidirectional Porous Iron.

PubMed

Kovačič, Aljaž; Borovinšek, Matej; Vesenjak, Matej; Ren, Zoran

2018-01-26

This paper addresses the problem of reconstructing realistic, irregular pore geometries of lotus-type porous iron for computer models that allow for simple porosity and pore size variation in computational characterization of their mechanical properties. The presented methodology uses image-recognition algorithms for the statistical analysis of pore morphology in real material specimens, from which a unique fingerprint of pore morphology at a certain porosity level is derived. The representative morphology parameter is introduced and used for the indirect reconstruction of realistic and statistically representative pore morphologies, which can be used for the generation of computational models with an arbitrary porosity. Such models were subjected to parametric computer simulations to characterize the dependence of engineering elastic modulus on the porosity of lotus-type porous iron. The computational results are in excellent agreement with experimental observations, which confirms the suitability of the presented methodology of indirect pore geometry reconstruction for computational simulations of similar porous materials.

Modeling the Relations Among Morphological Awareness Dimensions, Vocabulary Knowledge, and Reading Comprehension in Adult Basic Education Students.

PubMed

Tighe, Elizabeth L; Schatschneider, Christopher

2016-01-01

This study extended the findings of Tighe and Schatschneider (2015) by investigating the predictive utility of separate dimensions of morphological awareness as well as vocabulary knowledge to reading comprehension in adult basic education (ABE) students. We competed two- and three-factor structural equation models of reading comprehension. A three-factor model of real word morphological awareness, pseudoword morphological awareness, and vocabulary knowledge emerged as the best fit and accounted for 79% of the reading comprehension variance. The results indicated that the constructs contributed jointly to reading comprehension; however, vocabulary knowledge was the only potentially unique predictor (p = 0.052), accounting for an additional 5.6% of the variance. This study demonstrates the feasibility of applying a latent variable modeling approach to examine individual differences in the reading comprehension skills of ABE students. Further, this study replicates the findings of Tighe and Schatschneider (2015) on the importance of differentiating among dimensions of morphological awareness in this population.

Evaluation de L’Effet du Vieillissement des Equipages sur les Consequences du Decalage Horaire (Evaluation of Crew Members Aging on Jet-Lag Consequences)

DTIC Science & Technology

2000-08-01

Ergonomia , 1987, 30, 13 79- physique que psychologique. Cela tend A damontrer que 1393. dans des conditions militaires op~rationnelles, les 2...melatonin. Ergonomia , 1987, 30, 1379- 1393. 2 - BLOIS R, FEINBERG I., GAILLARD J.M., KUPFER D.J. and WEBB W.B. Sleep in normal and pathological aging

Electromagnetic Noise Interference and Compatibility

DTIC Science & Technology

1975-11-01

RADIO INTERFERENCE by C.Fengler 7 LES CHARGES ELECTROSTATIQUES ET LES PERTURBATIONS QU’ELLES ENTRAINENT DANS LES LIAISONS RADIOELECTRIQUES par...PAR LA TRANSMISSION DANS UN SYSTFJE INTEGRE AEROPORTE par r,.David et M.Vanneizel 31 Not available at time of priating Reference DIGITAL DATA...TRANSMISSION IN AIRCRAFT: EMC-PROBLEMS AND POSSIBLE SOLUTIONS by R.Rode 32 GENERATIONS El EFFETS DES TENSIONS PARASITES DE CONDUCTION ET DE RAVONNEMENT ENTRE

Impuretés et systèmes corrélés. Des chaînes aux cuprates supraconducteurs

NASA Astrophysics Data System (ADS)

Bobroff, J.

2005-01-01

Impurities and correlated systems Discovery of high TC superconductors has opened the new field of strongly correlated fermions physics. In these compounds, mostly transition metal oxides, strong correlations between electrons affect sharply their electronic properties. In order to determine accurately these correlations and their possible link with superconductivity, we study the effect of local defects such as non magnetic impurities. In fact, in the more simple case of insulating spin chains and ladders, these impurities induce a staggered magnetism in their neighborhood which reveals the underlying electronic correlations. Similar effects are observed in high TC superconductors, using local probes such as nuclear magnetic resonance. These observations allow to get a better understanding of both normal and superconducting state of these oxides, both full of surprises. La découverte des supraconducteurs à haute température critique a ouvert la voie à une nouvelle physique, celle des fermions fortement corrélés. Dans ces systèmes, le plus souvent des oxydes de métaux de transition, les fortes corrélations entre électrons affectent profondément leurs propriétés électroniques et induisent de nouveaux états originaux : liquides de spins, supraconductivité, etc. Pour mesurer ces corrélations et ainsi déterminer leur lien éventuel avec la supraconductivité, nous proposons d'étudier l'effet de défauts ponctuels tels que des impuretés non magnétiques. En effet, dans le cas plus simple de chaînes ou d'échelles de spin isolantes, ces impuretés induisent dans leur voisinage immédiat un magnétisme alterné révélateur des corrélations électroniques. Des effets semblables sont observés dans les supraconducteurs à haute température critique, grâce à des sondes locales comme la résonance magnétique nucléaire. Ces observations permettent de mieux comprendre à la fois l'état normal et supraconducteur de ces oxydes, tous deux riches en surprises.

Les hémodialysés HVC sont-ils vraiment des patients difficiles à traiter?

PubMed Central

Krati, Khadija; Cherquaoui, Hind; Oubaha, Sofia; Samlani, Zouhour

2015-01-01

L'hépatite C demeure la principale infection virale chez l'hémodialysé, dont la prise en charge thérapeutique ainsi que la gestion de ses effets secondaires restent difficiles. Il s'agit d'une étude rétrospective portant sur tous les patients atteints d'hépatite C chronique ayant une insuffisance rénale chronique sous hémodialyse, suivis au service de gastroentérologie au CHU Mohamed VI de Marrakech sur une période de Janvier 2004 à Décembre 2014. Sur un total de 355 cas d'hépatite virale C, 13 patients étaient hémodialysés (3,66%). Dix patients ont été traités, soit 76,94% des cas. Le traitement n’était pas indiqué chez 2 patients ayant une fibrose minime sans cytolyse. Il était contre-indiqué chez une patiente multitarée. Deux malades ont eu une réponse virologique rapide et 5 une réponse virologique précoce. Le taux de réponse virologique soutenue était de 40%, 30% des patients étaient non répondeurs. Le traitement fut arrêté chez 2 patientes pour effets secondaires sévères. Un seul patient a été candidat à une transplantation rénale. En analyse multivariée, la réponse virologique soutenue a été significativement associée à certains facteurs prédictifs de bonne réponse thérapeutique: Age jeune ≤40 ans (P=0,0057), fibrose minime F1-F2 (P=0,03), génotype non 1 (P=0,0064), charge virale préthérapeutique <800000 UI/ml (P=0,013), et l'absence d'arrêt thérapeutique (P=0,028). La gestion efficace des effets secondaires du traitement de HVC permet d'obtenir chez l'hémodialysé un taux de réponse virologique soutenue avoisinant celui de la population générale. PMID:27022433

Durcissement superficiel de la fonte grise Ft25 induit par un traitement de surface dans le moule

NASA Astrophysics Data System (ADS)

Bouitna, Mohamed; Boutarek-Zaourar, Naïma; Mansour, Samir; Chentouf, Samir Mourad; Mossang, Eric

2018-02-01

L'objectif de cette étude est la consolidation en surface de la fonte grise lamellaire Ft25 par un dépôt riche en manganèse en développant une méthode combinant en une seule opération l'élaboration et le traitement de surface dans le moule. Les effets de la granulométrie du ferro-manganèse (80 % Mn + 20 % Fe), ainsi que l'épaisseur des pièces en fontes sur les couches formées ont été étudiés. On a retenu trois granulométries du ferro-manganèse de 0,18 mm, 0,25 mm et 0,5 mm pour le traitement des pièces en fontes présentant des épaisseurs de 25 mm, 100 mm et 200 mm. Parmi les résultats obtenus, on distingue une consolidation des propriétés en surface induite par la formation d'une couche riche en manganèse continue et homogène. L'effet de la granulométrie du ferro-manganèse sur l'épaisseur de la couche traitée a été mis en évidence. La variation de l'épaisseur des couches formées diminue avec l'augmentation de la granulométrie du ferro-manganèse. Pour une pièce de 100 mm d'épaisseur, la couche formée est estimée à 350 μm pour une granulométrie de 0,18 alors qu'elle n'est que de 180 μm pour une granulométrie de 0,5. L'effet de l'épaisseur de la pièce n'est en revanche pas assez prononcé sur la taille des couches formées. Une amélioration nette de la résistance, à l'usure de la fonte traitée en relation avec les transformations en surface, a été mise en évidence.

Les neuropathies liées au VIH/SIDA: une étude clinique chez les patients infectés par le VIH au Centre d'Excellence VIH/SIDA de l'Université de Lubumbashi

PubMed Central

Kabongo, Joe Katabwa; Kaputu-Kalala-Malu, Célestin; Luboya, Oscar; Mutombo, Valerien; Ntambwe, Abel; Mapatano, Mala Ali; Mukendi, Kavulu Mayamba

2015-01-01

Introduction En vue d'améliorer la prise en charge des patients souffrant de neuropathie (NP) associées à l'infection HIV, nous avons essayé de déterminer le profil clinique des personnes souffrant de NP au cours du suivi thérapeutique de leur infection HIV. Méthodes Il s'agit d'une étude transversale (n= 101) menée au centre d'excellence depuis 1 an. Notre analyse est essentiellement clinique. Par un examen clinique minutieux, nous avons recherché tous les symptômes et signes cliniques des NP. Subjectivement, les douleurs dominent le tableau. Pour affiner leur diagnostic, nous avons utilisé l’échelle DN4 (Diagnostic des douleurs neuropathiques) et l’échelle EVA (Evaluation de la gravité des douleurs). Nous avons ensuite analysé nos données en fonction de certains autres facteurs épidémiologiques tels que le taux des CD4, le traitement anti-HIV etc. Résultats Les 101 patients représentent 3,12% de la cohorte générale; 53,3% des patients présentent une abolition des réflexes ostéotendineux des membres inférieurs; 77,89% présentent une hypoesthésie thermo algique en chaussette et en gants; 25% ont présenté une amyotrophie des membres inférieurs; 76,5% ont été soumis à un traitement antirétroviral contenant la stavudine; 11,7% ont pris la didanosine (DDI) et Abacavir (ABC). 84% ont une moyenne de CD4 de 292 cel/mm3. Conclusion La NP altère la qualité de vie de nos patients et diminue l'adhérence au traitement antirétroviral. Plusieurs facteurs sont incriminés dans la survenue de la NP, l'effet direct des antirétroviraux, l'effet inflammatoire dysimmunitaire, l'effet infectieux lié aux infections opportunistes. D'autres facteurs seront recherchés et analysés ultérieurement. PMID:26185582

Effects of metalinguistic awareness on reading comprehension and the mediator role of reading fluency from grades 2 to 4.

PubMed

Li, Liping; Wu, Xinchun

2015-01-01

This study examined the contribution of metalinguistic awareness including morphological awareness, phonological awareness and orthographical awareness to reading comprehension, and the role of reading fluency as a mediator of the effects of metalinguistic awareness on reading comprehension from grades 2 to 4. Four hundred and fifteen elementary students in China mainland were administered a test battery that included measures of morphological awareness, phonological awareness, orthographical awareness, reading fluency, reading comprehension and IQ. Hierarchical regression and structural equation models (SEM) were used to analyze the data. Morphological awareness uniquely explained 9%, 10% and 13% variance of reading comprehension respectively from grade 2 to grade 4, however, phonological awareness and orthographical awareness did not contribute to reading comprehension; Reading fluency partially mediated the effect of morphological awareness on reading comprehension in grades 2-4. These findings indicated that reading fluency and morphological awareness should be facilitated in the Chinese instruction. Morphological awareness played an important role in Chinese reading and affected reading comprehension in grades 2 to 4; Reading fluency was a significant link between morphological awareness and reading comprehension in grades 2-4.

Tuning the Morphologies of MnO/C Hybrids by Space Constraint Assembly of Mn-MOFs for High Performance Li Ion Batteries.

PubMed

Sun, Dan; Tang, Yougen; Ye, Delai; Yan, Jun; Zhou, Haoshen; Wang, Haiyan

2017-02-15

Morphology controllable fabrication of electrode materials is of great significance but is still a major challenge for constructing advanced Li ion batteries. Herein, we propose a novel space constraint assembly approach to tune the morphology of Mn(terephthalic acid) (PTA)-MOF, in which benzonic acid was employed as a modulator to adjust the available MOF assembly directions. As a result, Mn(PTA)-MOFs with microquadrangulars, microflakes, and spindle-like microrods morphologies have been achieved. MnO/C hybrids with preserved morphologies were further obtained by self-sacrificial and thermal transformation of Mn(PTA)-MOFs. As anodes for Li ion batteries, these morphologies showed great influence on the electrochemical properties. Owing to the abundant porous structure and unique architecture, the MnO/C spindle-like microrods demonstrated superior electrochemical properties with a high reversible capacity of 1165 mAh g -1 at 0.3 A g -1 , excellent rate capability of 580 mAh g -1 at 3 A g -1 , and no considerable capacity loss after 200 cycles at 1 A g -1 . This strategy could be extended to engineering the morphology of other MOF-derived functional materials in various structure-dependent applications.

Effects of Metalinguistic Awareness on Reading Comprehension and the Mediator Role of Reading Fluency from Grades 2 to 4

PubMed Central

Li, Liping; Wu, Xinchun

2015-01-01

Purpose This study examined the contribution of metalinguistic awareness including morphological awareness, phonological awareness and orthographical awareness to reading comprehension, and the role of reading fluency as a mediator of the effects of metalinguistic awareness on reading comprehension from grades 2 to 4. Methods Four hundred and fifteen elementary students in China mainland were administered a test battery that included measures of morphological awareness, phonological awareness, orthographical awareness, reading fluency, reading comprehension and IQ. Hierarchical regression and structural equation models (SEM) were used to analyze the data. Results Morphological awareness uniquely explained 9%, 10% and 13% variance of reading comprehension respectively from grade 2 to grade 4, however, phonological awareness and orthographical awareness did not contribute to reading comprehension; Reading fluency partially mediated the effect of morphological awareness on reading comprehension in grades 2-4. Conclusions These findings indicated that reading fluency and morphological awareness should be facilitated in the Chinese instruction. Morphological awareness played an important role in Chinese reading and affected reading comprehension in grades 2 to 4; Reading fluency was a significant link between morphological awareness and reading comprehension in grades 2-4. PMID:25799530

A combinatorial approach to angiosperm pollen morphology.

PubMed

Mander, Luke

2016-11-30

Angiosperms (flowering plants) are strikingly diverse. This is clearly expressed in the morphology of their pollen grains, which are characterized by enormous variety in their shape and patterning. In this paper, I approach angiosperm pollen morphology from the perspective of enumerative combinatorics. This involves generating angiosperm pollen morphotypes by algorithmically combining character states and enumerating the results of these combinations. I use this approach to generate 3 643 200 pollen morphotypes, which I visualize using a parallel-coordinates plot. This represents a raw morphospace. To compare real-world and theoretical morphologies, I map the pollen of 1008 species of Neotropical angiosperms growing on Barro Colorado Island (BCI), Panama, onto this raw morphospace. This highlights that, in addition to their well-documented taxonomic diversity, Neotropical rainforests also represent an enormous reservoir of morphological diversity. Angiosperm pollen morphospace at BCI has been filled mostly by pollen morphotypes that are unique to single plant species. Repetition of pollen morphotypes among higher taxa at BCI reflects both constraint and convergence. This combinatorial approach to morphology addresses the complexity that results from large numbers of discrete character combinations and could be employed in any situation where organismal form can be captured by discrete morphological characters. © 2016 The Author(s).

A combinatorial approach to angiosperm pollen morphology

PubMed Central

2016-01-01

Angiosperms (flowering plants) are strikingly diverse. This is clearly expressed in the morphology of their pollen grains, which are characterized by enormous variety in their shape and patterning. In this paper, I approach angiosperm pollen morphology from the perspective of enumerative combinatorics. This involves generating angiosperm pollen morphotypes by algorithmically combining character states and enumerating the results of these combinations. I use this approach to generate 3 643 200 pollen morphotypes, which I visualize using a parallel-coordinates plot. This represents a raw morphospace. To compare real-world and theoretical morphologies, I map the pollen of 1008 species of Neotropical angiosperms growing on Barro Colorado Island (BCI), Panama, onto this raw morphospace. This highlights that, in addition to their well-documented taxonomic diversity, Neotropical rainforests also represent an enormous reservoir of morphological diversity. Angiosperm pollen morphospace at BCI has been filled mostly by pollen morphotypes that are unique to single plant species. Repetition of pollen morphotypes among higher taxa at BCI reflects both constraint and convergence. This combinatorial approach to morphology addresses the complexity that results from large numbers of discrete character combinations and could be employed in any situation where organismal form can be captured by discrete morphological characters. PMID:27881756

The Role of Morphological and Phonological Awareness in the Early Development of Word Spelling and Reading in Typically Developing and Disabled Arabic Readers.

PubMed

Saiegh-Haddad, Elinor; Taha, Haitham

2017-11-01

The study is a cross-sectional developmental investigation of morphological and phonological awareness in word spelling and reading in Arabic in reading-accuracy disabled (RD) children and in age-matched typically developing (TR) controls in grades 1-4 (N = 160). Morphological awareness tasks targeted the root and word pattern derivational system of Arabic, in both the oral and the written modalities. Phonological awareness employed a variety of orally administered segmentation and deletion tasks. The results demonstrated early deficits in morphological awareness, besides deficits in phonological awareness, in RD children as compared with typically developing controls, as well as in word and pseudoword spelling and reading (voweled and unvoweled). While phonological awareness emerged as the strongest predictor of reading, morphological awareness was also found to predict unique variance in reading, and even more so in spelling, beyond phonological awareness and cognitive skills. The results demonstrate the early emergence of morphological awareness deficits, alongside phonological deficits in Arabic RD, as well as the role of morphological processing in early reading and spelling. These findings reflect the centrality of derivational morphology in the structure of the spoken and the written Arabic word. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Spontaneous Epithelioid Hemangiosarcoma in a Rhesus Monkey (Macaca mulatta)

PubMed Central

Tsuchiya, Takayuki; Gray, Tasha L; Gatto, Nicholas T; Forest, Thomas; Machotka, Sam V; Troth, Sean P; Prahalada, Srinivasa

2014-01-01

Epithelioid hemangiosarcoma is a rare malignant endothelial neoplasia with a unique, predominantly epithelioid morphology. A 4-y-old rhesus monkey from our laboratory had multiple neoplastic nodules in a digit, limb skin, hindlimb muscle, and visceral organs including lung, heart, and brain. The nodules were composed of pleomorphic, polygonal, epithelioid, neoplastic cells that were arranged in sheets, nests, and cords and supported by variably dense fibrovascular connective tissue. The morphologic features of this tumor were predominantly epithelioid. However, some regions contained cystic spaces, clefts, and channel-like structures, all of which were lined with morphologically distinct neoplastic endothelial cells. These neoplastic cells, with or without epithelioid morphology, were positive immunohistochemically for CD31, factor VIII-related antigen, and vimentin. The presence of multiple metastatic nodules, high mitotic rate, and extensive Ki67-positive staining were consistent with malignancy. This report is the first description of epithelioid hemangiosarcoma in a rhesus monkey. PMID:25296017

Spontaneous epithelioid hemangiosarcoma in a rhesus monkey (Macaca mulatta).

PubMed

Tsuchiya, Takayuki; Gray, Tasha L; Gatto, Nicholas T; Forest, Thomas; Machotka, Sam V; Troth, Sean P; Prahalada, Srinivasa

2014-08-01

Epithelioid hemangiosarcoma is a rare malignant endothelial neoplasia with a unique, predominantly epithelioid morphology. A 4-y-old rhesus monkey from our laboratory had multiple neoplastic nodules in a digit, limb skin, hindlimb muscle, and visceral organs including lung, heart, and brain. The nodules were composed of pleomorphic, polygonal, epithelioid, neoplastic cells that were arranged in sheets, nests, and cords and supported by variably dense fibrovascular connective tissue. The morphologic features of this tumor were predominantly epithelioid. However, some regions contained cystic spaces, clefts, and channel-like structures, all of which were lined with morphologically distinct neoplastic endothelial cells. These neoplastic cells, with or without epithelioid morphology, were positive immunohistochemically for CD31, factor VIII-related antigen, and vimentin. The presence of multiple metastatic nodules, high mitotic rate, and extensive Ki67-positive staining were consistent with malignancy. This report is the first description of epithelioid hemangiosarcoma in a rhesus monkey.

BiVO4 microstructures with various morphologies: Synthesis and characterization

NASA Astrophysics Data System (ADS)

Wu, Min; Jing, Qifeng; Feng, Xinyan; Chen, Limiao

2018-01-01

Bismuth vanadate (BiVO4) microstructures with dumbbell, rod, ellipsoid, sphere, and cake-like morphologies have been successfully fabricated by using a surfactant-free hydrothermal method, in which the morphology of the BiVO4 microstructures can be tuned by simply varying the molar ratio of Bi(NO)3·5H2O to NaVO3 in the starting materials. Based on a series of contrast experiments, the probable formation mechanism of the BiVO4 microstructures with multiple shapes have been proposed. The photocatalytic performances of the as-prepared BiVO4 microstructures have been evaluated by studying the degradation of Rhodamine B solutions under visible light irradiation. The results reveal that the cake-like BiVO4 microstructures exhibit the higher photocatalytic activity than other BiVO4 microstructures due to its high surface area and unique morphology.

Enhancement of morphological and vascular features in OCT images using a modified Bayesian residual transform

PubMed Central

Tan, Bingyao; Wong, Alexander; Bizheva, Kostadinka

2018-01-01

A novel image processing algorithm based on a modified Bayesian residual transform (MBRT) was developed for the enhancement of morphological and vascular features in optical coherence tomography (OCT) and OCT angiography (OCTA) images. The MBRT algorithm decomposes the original OCT image into multiple residual images, where each image presents information at a unique scale. Scale selective residual adaptation is used subsequently to enhance morphological features of interest, such as blood vessels and tissue layers, and to suppress irrelevant image features such as noise and motion artefacts. The performance of the proposed MBRT algorithm was tested on a series of cross-sectional and enface OCT and OCTA images of retina and brain tissue that were acquired in-vivo. Results show that the MBRT reduces speckle noise and motion-related imaging artefacts locally, thus improving significantly the contrast and visibility of morphological features in the OCT and OCTA images. PMID:29760996

Astragalar Morphology of Selected Giraffidae.

PubMed

Solounias, Nikos; Danowitz, Melinda

2016-01-01

The artiodactyl astragalus has been modified to exhibit two trochleae, creating a double pullied structure allowing for significant dorso-plantar motion, and limited mediolateral motion. The astragalus structure is partly influenced by environmental substrates, and correspondingly, morphometric studies can yield paleohabitat information. The present study establishes terminology and describes detailed morphological features on giraffid astragali. Each giraffid astragalus exhibits a unique combination of anatomical characteristics. The giraffid astragalar morphologies reinforce previously established phylogenetic relationships. We find that the enlargement of the navicular head is a feature shared by all giraffids, and that the primitive giraffids possess exceptionally tall astragalar heads in relation to the total astragalar height. The sivatheres and the okapi share a reduced notch on the lateral edge of the astragalus. We find that Samotherium is more primitive in astragalar morphologies than Palaeotragus, which is reinforced by tooth characteristics and ossicone position. Diagnostic anatomical characters on the astragalus allow for giraffid species identifications and a better understanding of Giraffidae.

Origin of the unique morphology of the shoulder girdle in turtles

PubMed Central

Nagashima, Hiroshi; Hirasawa, Tatsuya; Sugahara, Fumiaki; Takechi, Masaki; Usuda, Ryo; Sato, Noboru; Kuratani, Shigeru

2013-01-01

The shoulder girdle of turtles has a triradiate morphology. Although its dorsal process represents the scapular blade, the skeletal identities of the two ventral processes remain uncertain. To elucidate the question, developmental patterns of the girdles were compared between Chinese soft-shelled turtles, chickens, and mice. Despite the morphological diversity of adults, the initial primordia of the shoulder girdles showed similar morphological patterns. The ventral two processes developed from the anlagen comparable to those of the acromion and the coracoid in other amniotes. The developmental pattern of the acromion is very similar among embryos, whereas that of the coracoid in mammals differs from that in non-mammals, implying that coracoids are not homologous between non-mammals and mammals. Therefore, amniotes have retained the ancestral pattern of the girdle anlage, and the shoulder girdle of turtles has been achieved through a transformation of the pattern in the late ontogenic period. PMID:24117338

The spinning apparatus of webspinners – functional-morphology, morphometrics and spinning behaviour

PubMed Central

Büsse, Sebastian; Hörnschemeyer, Thomas; Hohu, Kyle; McMillan, David; Edgerly, Janice S.

2015-01-01

Webspinners (Insecta: Embioptera) have a distinctly unique behaviour with related morphological characteristics. Producing silk with the basitarsomeres of their forelegs plays a crucial role in the lives of these insects – providing shelter and protection. The correlation between body size, morphology and morphometrics of the spinning apparatus and the spinning behaviour of Embioptera was investigated for seven species using state-of-the-art methodology for behavioural as well as for morphological approaches. Independent contrast analysis revealed correlations between morphometric characters and body size. Larger webspinners in this study have glands with greater reservoir volume, but in proportionally smaller tarsi relative to body size than in the smaller species. Furthermore, we present a detailed description and review of the spinning apparatus in Embioptera in comparison to other arthropods and substantiate the possible homology of the embiopteran silk glands to class III dermal silk glands of insects. PMID:25950122

Transparent, flexible supercapacitors from nano-engineered carbon films.

PubMed

Jung, Hyun Young; Karimi, Majid B; Hahm, Myung Gwan; Ajayan, Pulickel M; Jung, Yung Joon

2012-01-01

Here we construct mechanically flexible and optically transparent thin film solid state supercapacitors by assembling nano-engineered carbon electrodes, prepared in porous templates, with morphology of interconnected arrays of complex shapes and porosity. The highly textured graphitic films act as electrode and current collector and integrated with solid polymer electrolyte, function as thin film supercapacitors. The nanostructured electrode morphology and the conformal electrolyte packaging provide enough energy and power density for the devices in addition to excellent mechanical flexibility and optical transparency, making it a unique design in various power delivery applications.

Transparent, flexible supercapacitors from nano-engineered carbon films

PubMed Central

Jung, Hyun Young; Karimi, Majid B.; Hahm, Myung Gwan; Ajayan, Pulickel M.; Jung, Yung Joon

2012-01-01

Here we construct mechanically flexible and optically transparent thin film solid state supercapacitors by assembling nano-engineered carbon electrodes, prepared in porous templates, with morphology of interconnected arrays of complex shapes and porosity. The highly textured graphitic films act as electrode and current collector and integrated with solid polymer electrolyte, function as thin film supercapacitors. The nanostructured electrode morphology and the conformal electrolyte packaging provide enough energy and power density for the devices in addition to excellent mechanical flexibility and optical transparency, making it a unique design in various power delivery applications. PMID:23105970

Transparent, flexible supercapacitors from nano-engineered carbon films

NASA Astrophysics Data System (ADS)

Jung, Hyun Young; Karimi, Majid B.; Hahm, Myung Gwan; Ajayan, Pulickel M.; Jung, Yung Joon

2012-10-01

Here we construct mechanically flexible and optically transparent thin film solid state supercapacitors by assembling nano-engineered carbon electrodes, prepared in porous templates, with morphology of interconnected arrays of complex shapes and porosity. The highly textured graphitic films act as electrode and current collector and integrated with solid polymer electrolyte, function as thin film supercapacitors. The nanostructured electrode morphology and the conformal electrolyte packaging provide enough energy and power density for the devices in addition to excellent mechanical flexibility and optical transparency, making it a unique design in various power delivery applications.

The ROCK isoforms differentially regulate the morphological characteristics of carcinoma cells.

PubMed

Jerrell, Rachel J; Leih, Mitchell J; Parekh, Aron

2017-06-26

Rho-associated kinase (ROCK) activity drives cell migration via actomyosin contractility. During invasion, individual cancer cells can transition between 2 modes of migration, mesenchymal and amoeboid. Changes in ROCK activity can cause a switch between these migration phenotypes which are defined by distinct morphologies. However, recent studies have shown that the ROCK isoforms are not functionally redundant as previously thought. Therefore, it is unclear whether the ROCK isoforms play different roles in regulating migration phenotypes. Here, we found that ROCK1 and ROCK2 differentially regulate carcinoma cell morphology resulting in intermediate phenotypes that share some mesenchymal and amoeboid characteristics. These findings suggest that the ROCK isoforms play unique roles in the phenotypic plasticity of mesenchymal carcinoma cells which may have therapeutic implications.

Three-dimensional echocardiography of congenital abnormalities of the left atrioventricular valve

PubMed Central

Rice, Kathryn

2015-01-01

Congenital abnormalities of the left atrioventricular (AV) valve are a significant diagnostic challenge. Traditionally, reliance has been placed on two-dimensional echocardiographic (2DE) imaging to guide recognition of the specific morphological features. Real-time 3DE can provide unique views of the left AV valve with the potential to improve understanding of valve morphology and function to facilitate surgical planning. This review illustrates the features of congenital abnormalities of the left AV valve assessed by 3DE. The similarities and differences in morphology between different lesions are described, both with respect to the valve itself and supporting chordal apparatus. The potential advantages as well as limitations of this technique in clinical practice are outlined. PMID:26693328

Synthetic Design of Polysulfone Membranes: Morphological Effect on Property and Performance in Flow Batteries

NASA Astrophysics Data System (ADS)

Gindt, Brandon

This dissertation outlines a novel path towards improved understanding and function of proton exchange membranes (PEMs) for redox flow batteries, a large-scale battery storage device. This research uses synthetic methods and nanotechnology through two different approaches to prepare tailored polymer membranes: 1) Ion exchange membranes with enhanced chemical structures to promote membrane morphology on the nano-scale were prepared. Specifically, functional polysulfones (PSUs) were synthesized from different pre-sulfonated monomers. These PSUs have controlled placement and content of unique sulfonic acid moieties. PEMs were fabricated and characterized. The new PEMs showed desirable physical properties and performance in a vanadium redox flow battery (VRFB) cell. 2) Nanoporous PSU membranes were fabricated via post-hydrolysis of polylactide (PLA) from PLA-PSU-PLA triblock copolymer membranes. The controlled morphology and pore size of the resulting nanoporous membranes were evaluated by different microscopy and scattering techniques to understand structure-property relationships. Further, the resulting nanopore surface was chemically modified with sulfonic acid moieties. Membranes were analyzed and evaluated as separators for a VRFB. The chemically modified nanoporous PEMs exhibited unique behavior with respect to their ion conductivity when exposed to solutions of increasing acid concentration. In addition, the hierarchical micro-nanoporous membranes developed further showed promising structure and properties.

Adaptive bill morphology for enhanced tool manipulation in New Caledonian crows

PubMed Central

Matsui, Hiroshi; Hunt, Gavin R.; Oberhofer, Katja; Ogihara, Naomichi; McGowan, Kevin J.; Mithraratne, Kumar; Yamasaki, Takeshi; Gray, Russell D.; Izawa, Ei-Ichi

2016-01-01

Early increased sophistication of human tools is thought to be underpinned by adaptive morphology for efficient tool manipulation. Such adaptive specialisation is unknown in nonhuman primates but may have evolved in the New Caledonian crow, which has sophisticated tool manufacture. The straightness of its bill, for example, may be adaptive for enhanced visually-directed use of tools. Here, we examine in detail the shape and internal structure of the New Caledonian crow’s bill using Principal Components Analysis and Computed Tomography within a comparative framework. We found that the bill has a combination of interrelated shape and structural features unique within Corvus, and possibly birds generally. The upper mandible is relatively deep and short with a straight cutting edge, and the lower mandible is strengthened and upturned. These novel combined attributes would be functional for (i) counteracting the unique loading patterns acting on the bill when manipulating tools, (ii) a strong precision grip to hold tools securely, and (iii) enhanced visually-guided tool use. Our findings indicate that the New Caledonian crow’s innovative bill has been adapted for tool manipulation to at least some degree. Early increased sophistication of tools may require the co-evolution of morphology that provides improved manipulatory skills. PMID:26955788

Morphological characterization and molecular fingerprinting of Nostoc strains by multiplex RAPD.

PubMed

Hillol, Chakdar; Pabbi, Sunil

2012-01-01

Morphological parameters studied for the twenty selected Nostoc strains were mostly found to be consistent with the earlier reports. But the shape of akinetes observed in this study was a little deviation from the existing descriptions and heterocyst frequency was also found to be different in different strains in spite of growing in the same nitrogen free media. Multiplex RAPD produced reproducible and completely polymorphic amplification profiles for all the strains including some strain specific unique bands which are intended to be useful for identification of those strains. At least one to a maximum of two unique bands was produced by different dual primer combinations. For ten strains out of twenty, strain specific bands were found to be generated. Cluster analysis revealed a vast heterogeneity among these Nostoc strains and no specific clustering based on geographical origin was found except a few strains. It was also observed that morphological data may not necessarily correspond to the genetic data in most of the cases. CCC92 (Nostoc muscorum) and CCC48 (Nostoc punctiforme) showed a high degree of similarity which was well supported by high bootstrap value. The level of similarity of the strains ranged from 0.15 to 0.94. Cluster analysis based on multiplex RAPD showed a good fit revealing the discriminatory power of this technique.

Velcro-Like System Used to Fix a Protective Faecal Shield on Weevil Larvae.

PubMed

Skuhrovec, Jiří; Stejskal, Robert; Trnka, Filip; di Giulio, Andrea

2017-01-01

The last instar larva and pupa of Eucoeliodes mirabilis (A. Villa & G. B. Villa, 1835) (Curculionidae: Ceutorhynchini) are described using drawings and SEM images and are compared and keyed with already described larvae of 58 other ceutorhynchinae taxa. The larval body has an effective combination of morphological adaptations that assist a unique biological defensive strategy. All larval stages of E. mirabilis feed ectophytically on leaves of Euonymus europaeus L. (Celastraceae), and the larval body is covered with a thick faecal shield. The fixation of this protective shield on the larval back is performed by a peculiar dorsal microsculpture composed of a dense carpet of microtrichia on the thorax and abdomen, which serves effectively as a velcro system. Because of this strategy, macrosetae on the larval and pupal body of E. mirabilis are completely reduced. Larvae of E. mirabilis also have distinct morphological adaptations for protecting the spiracles against intrusion of faeces and avoiding occlusion of the tracheal system: a) microtrichia around spiracles are slightly shorter, distinctly stronger and are arranged with high-density and in clusters and b) spiracles are protected by an external safety valve. This strategy of E. mirabilis larvae is unique, although somewhat similar to that of Criocerinae and Blepharida-group leave beetles (Galerucinae) (both Coleoptera: Chrysomelidae), but with distinctly different morphological adaptations.

Velcro-Like System Used to Fix a Protective Faecal Shield on Weevil Larvae

PubMed Central

Stejskal, Robert; Trnka, Filip; di Giulio, Andrea

2017-01-01

The last instar larva and pupa of Eucoeliodes mirabilis (A. Villa & G. B. Villa, 1835) (Curculionidae: Ceutorhynchini) are described using drawings and SEM images and are compared and keyed with already described larvae of 58 other ceutorhynchinae taxa. The larval body has an effective combination of morphological adaptations that assist a unique biological defensive strategy. All larval stages of E. mirabilis feed ectophytically on leaves of Euonymus europaeus L. (Celastraceae), and the larval body is covered with a thick faecal shield. The fixation of this protective shield on the larval back is performed by a peculiar dorsal microsculpture composed of a dense carpet of microtrichia on the thorax and abdomen, which serves effectively as a velcro system. Because of this strategy, macrosetae on the larval and pupal body of E. mirabilis are completely reduced. Larvae of E. mirabilis also have distinct morphological adaptations for protecting the spiracles against intrusion of faeces and avoiding occlusion of the tracheal system: a) microtrichia around spiracles are slightly shorter, distinctly stronger and are arranged with high-density and in clusters and b) spiracles are protected by an external safety valve. This strategy of E. mirabilis larvae is unique, although somewhat similar to that of Criocerinae and Blepharida-group leave beetles (Galerucinae) (both Coleoptera: Chrysomelidae), but with distinctly different morphological adaptations. PMID:28125664

Unique morphological changes in plant pathogenic phytoplasma-infected petunia flowers are related to transcriptional regulation of floral homeotic genes in an organ-specific manner.

PubMed

Himeno, Misako; Neriya, Yutaro; Minato, Nami; Miura, Chihiro; Sugawara, Kyoko; Ishii, Yoshiko; Yamaji, Yasuyuki; Kakizawa, Shigeyuki; Oshima, Kenro; Namba, Shigetou

2011-09-01

Abnormal flowers are often induced by infection of certain plant pathogens, e.g. phytoplasma, but the molecular mechanisms underlying these malformations have remained poorly understood. Here, we show that infection with OY-W phytoplasma (Candidatus Phytoplasma asteris, onion yellows phytoplasma strain, line OY-W) affects the expression of the floral homeotic genes of petunia plants in an organ-specific manner. Upon infection with OY-W phytoplasma, floral morphological changes, including conversion to leaf-like structures, were observed in sepals, petals and pistils, but not in stamens. As the expression levels of homeotic genes differ greatly between floral organs, we examined the expression levels of homeotic genes in each floral organ infected by OY-W phytoplasma, compared with healthy plants. The expression levels of several homeotic genes required for organ development, such as PFG, PhGLO1 and FBP7, were significantly downregulated by the phytoplasma infection in floral organs, except the stamens, suggesting that the unique morphological changes caused by the phytoplasma infection might result from the significant decrease in expression of some crucial homeotic genes. Moreover, the expression levels of TER, ALF and DOT genes, which are known to participate in floral meristem identity, were significantly downregulated in the phytoplasma-infected petunia meristems, implying that phytoplasma would affect an upstream signaling pathway of floral meristem identity. Our results suggest that phytoplasma infection may have complex effects on floral development, resulting in the unique phenotypes that were clearly distinct from the mutant flower phenotypes produced by the knock-out or the overexpression of certain homeotic genes. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

Penis morphology in a Burmese amber harvestman

NASA Astrophysics Data System (ADS)

Dunlop, Jason A.; Selden, Paul A.; Giribet, Gonzalo

2016-02-01

A unique specimen of the fossil harvestman Halitherses grimaldii Giribet and Dunlop, 2005 (Arachnida: Opiliones) from the Cretaceous (ca. 99 Ma) Burmese amber of Myanmar reveals a fully extended penis. This is the first record of a male copulatory organ of this nature preserved in amber and is of special importance due to the age of the deposit. The penis has a slender, distally flattened truncus, a spatulate heart-shaped glans and a short distal stylus, twisted at the tip. In living harvestmen, the penis yields crucial characters for their systematics. Male genital morphology in H. grimaldii appears to be unique among the wider Dyspnoi clade to which this fossil belongs. The large eyes in the fossil differ markedly from other members of the subfamily Ortholasmatinae to which H. grimaldii was originally referred. Based on recent data, it has been argued that large eyes may be plesiomorphic for Palpatores (i.e. the suborders Eupnoi and Dyspnoi), potentially rendering this character plesiomorphic for the fossil too. Thus, the unique structure of the penis seen here, and the probable lack of diaphanous teeth, present in all other extant non-acropsopilionid Dyspnoi, suggest that H. grimaldii represents a new, extinct family of large-eyed dyspnoid harvestmen, Halithersidae fam. nov.; a higher taxon in amber diagnosed here on both somatic and genital characters.

Penis morphology in a Burmese amber harvestman.

PubMed

Dunlop, Jason A; Selden, Paul A; Giribet, Gonzalo

2016-02-01

A unique specimen of the fossil harvestman Halitherses grimaldii Giribet and Dunlop, 2005 (Arachnida: Opiliones) from the Cretaceous (ca. 99 Ma) Burmese amber of Myanmar reveals a fully extended penis. This is the first record of a male copulatory organ of this nature preserved in amber and is of special importance due to the age of the deposit. The penis has a slender, distally flattened truncus, a spatulate heart-shaped glans and a short distal stylus, twisted at the tip. In living harvestmen, the penis yields crucial characters for their systematics. Male genital morphology in H. grimaldii appears to be unique among the wider Dyspnoi clade to which this fossil belongs. The large eyes in the fossil differ markedly from other members of the subfamily Ortholasmatinae to which H. grimaldii was originally referred. Based on recent data, it has been argued that large eyes may be plesiomorphic for Palpatores (i.e. the suborders Eupnoi and Dyspnoi), potentially rendering this character plesiomorphic for the fossil too. Thus, the unique structure of the penis seen here, and the probable lack of diaphanous teeth, present in all other extant non-acropsopilionid Dyspnoi, suggest that H. grimaldii represents a new, extinct family of large-eyed dyspnoid harvestmen, Halithersidae fam. nov.; a higher taxon in amber diagnosed here on both somatic and genital characters.

Whipworm kinomes reflect a unique biology and adaptation to the host animal.

PubMed

Stroehlein, Andreas J; Young, Neil D; Korhonen, Pasi K; Chang, Bill C H; Nejsum, Peter; Pozio, Edoardo; La Rosa, Giuseppe; Sternberg, Paul W; Gasser, Robin B

2017-11-01

Roundworms belong to a diverse phylum (Nematoda) which is comprised of many parasitic species including whipworms (genus Trichuris). These worms have adapted to a biological niche within the host and exhibit unique morphological characteristics compared with other nematodes. Although these adaptations are known, the underlying molecular mechanisms remain elusive. The availability of genomes and transcriptomes of some whipworms now enables detailed studies of their molecular biology. Here, we defined and curated the full complement of an important class of enzymes, the protein kinases (kinomes) of two species of Trichuris, using an advanced and integrated bioinformatic pipeline. We investigated the transcription of Trichuris suis kinase genes across developmental stages, sexes and tissues, and reveal that selectively transcribed genes can be linked to central roles in developmental and reproductive processes. We also classified and functionally annotated the curated kinomes by integrating evidence from structural modelling and pathway analyses, and compared them with other curated kinomes of phylogenetically diverse nematode species. Our findings suggest unique adaptations in signalling processes governing worm morphology and biology, and provide an important resource that should facilitate experimental investigations of kinases and the biology of signalling pathways in nematodes. Copyright © 2017 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

NATO Human Resources (Manpower) Management (Gestion des ressources humaines (effectifs) de l’OTAN)

DTIC Science & Technology

2012-02-01

performances , la gestion des récompenses et du salaire, et la motivation du personnel. En conséquence, il faut que la gestion des ressources humaines...importance au fil du temps. Les ressources humaines, chargées à l’origine de l’embauche, du licenciement, de la paie et de la gestion des ...les effets des systèmes d’évaluation des performances ;

Afterrise: Deep Body Temperature Following Exercise

DTIC Science & Technology

1992-03-01

Egalement, les effets de la posture et des v~tements durant la recuperation et la temperature de la salle de recuperation furent examines. Cinq hommes se...chemise a manches courtes). Les temperatures rectales et de la peau furent mesurees A chaque minute durant les exercices et la r~cup~ration affectaient...overgarment. RESUME Cette etude fut entreprise pour documenter l’augmentation continue de la temperature rectale apres exercice dans la chaleur

Impact of Technologies on Learning in the Workplace. Final Report = L'effet des technologies d'apprentissage sur l'apprentissage a vie en milieu de travail.

ERIC Educational Resources Information Center

Dugas, Tim; Green, Lyndsay; Leckie, Norm

The use of learning technologies in the workplace and their impact on lifelong learning were examined. Data were collected from three sources: the literature on learning technologies and labor market trends affecting the adoption, implementation, and success of learning technologies in the workplace; case studies of 8 Canadian firms with 100 or…

Prevention des Toxicomanies Aupres des Filles avec des Problemes de Comportement: Effets a Court Terme (Prevention of Drug Addiction in Girls with Behavior Problems: Short-Term Effects).

ERIC Educational Resources Information Center

Vitaro, Frank; And Others

1992-01-01

This article, written in French, describes and evaluates the first phase of a program to prevent drug addiction among 110 fifth-grade girls with behavior problems in Montreal (Quebec, Canada). Evaluation of the instructional program showed positive results for student knowledge level, attitudes, and behaviors and supported program continuation…

Possibilité d'une nouvelle technologie de traitement des minerais de fer de l'Ouenza par radiométrie

NASA Astrophysics Data System (ADS)

Idres, A.; Bounouala, M.

2005-05-01

En l'absence d'une technologie fiable de traitement des haldes de minerais de fer, les caractéristiques minéralogiques et chimiques complexes et les effets néfastes des résidus miniers posent réellement un problème environnemental. A cet effet, une étude minéralogique et chimique du minerai de fer a été menée en utilisant des techniques multiples (microscopie optique, DRX, FX, MEB). En tenant compte de la nature des résidus, des échantillons représentatifs ont été testés par séparation radiométrique. Plusieurs paramètres ont été caractérisés tels que la vitesse de la bande transporteuse, le temps d'émission des rayons gamma et la granulométrie d'alimentation du procédé. Les résultats ainsi obtenus par cette méthode de séparation sont très significatifs en récupération et en teneur fer. Cependant, cette nouvelle technologie permet d'une part une meilleure valorisation des minerais de fer et d'autre part une réduction du tonnage stocké sur le carreau de la mine.

Effets tardifs d'une irradiation corporelle totale sur le métabolisme intraneuronal de la dopamine et de la sérotonine

NASA Astrophysics Data System (ADS)

Joubert, C.; Jacquet, N.; Lambert, F.; Martin, S.; Martin, C.

1998-04-01

Whole-body irradiation leads to delayed cognitive dysfunction which could result from perturbations of neurotransmission, specially the dopaminergic and the serotoninergic one. The aim of this study was to determine the concentrations of dopamine (DA), serotonin (5-HT) and their metabolites in three cerebral areas of rats, one month after (neutron-gamma) irradiation at 3.38Gy. An increase of DA, 5-HT, and their catabolites was observed. These effects are weak but observed in older rats. Au cours des mois suivant une irradiation corporell totale peuvent se manifester des troubles comportementaux qui pourraient être la conséquence d'altérations de la neuraotransmission, plus particulièrement de la transmission dopaminergique ou sérotoninergique. Nous avons recherché les variations des taux de dopamine (DA), de sérotonine (5-HT) et de leurs métabolites dans 3structures cérébrales 1 mois après une irradiation (neutron-gamma) à la dose de 3,38Gy. Les résultats préliminaires mettent en évidence une augmentation des taux de DA, de 5-HT et de leurs catabolites ; ces effets sont plus discrets mais similaires à ceux observés chez des animaux plus âgés.

Effet d'un champ magnétique uniforme sur les instabilités de Rayleigh-Bénard avec effet Soret

NASA Astrophysics Data System (ADS)

Ben Sassi, Mokhtar; Kaddeche, Slim; Abdennadher, Ali; Henry, Daniel; Hadid, Hamda Ben; Mojtabi, Abdelkader

2016-01-01

The effect of both magnitude and orientation of a uniform magnetic field on the critical transition occurring within an electrically conducting binary fluid layer, stratified in temperature and concentration, taking into account the Soret effect, is investigated numerically. For such a configuration, the results show that the critical thresholds corresponding to an arbitrary orientated magnetic field can be derived from those obtained for a vertical magnetic field and that the axes of the marginal cells are aligned with the horizontal component of the magnetic field. Moreover, an analytical study is conducted to investigate the impact of the magnetic field on long-wavelength instabilities. The effect of the magnetic field on such instabilities reveals a new phenomenon consisting in major changes of the unstable modes that lose their unicellular nature to regain their multi-roll characteristic, as it is the case without magnetic field for ψ <ψℓ0 = 131 Le / (34 - 131 Le). For a binary fluid characterized by a Lewis number Le and a separation factor ψ >ψℓ0, the value of the Hartmann number Haℓ (ψ , Le) corresponding to that transition responsible for a significant change in mass and heat transfer can be determined from the analytical relations derived in this work.

Diffraction-limited IR Microspectroscopy with IRENI

Treesearch

J. Sedlmair; B. Illman; M. Unger; C. Hirschmugl

2012-01-01

In a unique way, IRENI (Infrared environmental Imaging), operated at the Synchrotron Radiation Center in Madison, combines IR spectroscopy and IR imaging, revealing the chemical morphology of a sample. Most storage ring based IR confocal microscopes have to overcome a trade-off between spatial resolution versus...

Reading Comprehension Mediates the Relationship between Syntactic Awareness and Writing Composition in Children: A Longitudinal Study.

PubMed

Tong, Xiuhong; McBride, Catherine

2016-12-01

This research aimed to explore the relation between syntactic awareness and writing composition in 129 Hong Kong Chinese children. These children were from a ten-year longitudinal project. At each year, a number of measures were administered. The 129 children's data of nonverbal reasoning at age 4, phonological awareness, morphological awareness, vocabulary knowledge at age 8, reading comprehension at age 12 and syntactic awareness and writing composition skills at ages 11 and 12 were included in this study. Syntactic awareness was longitudinally and uniquely predictive of Chinese children's writing composition, and children's performance in early writing composition was uniquely associated with their later syntactic skills, even when controlling for the contributions from age, nonverbal and verbal abilities, phonological awareness, and morphological awareness. The relationship between syntactic awareness and writing composition was mediated by children's performance in reading comprehension. These findings may suggest a reciprocal relation between syntactic awareness and writing composition, and this association may vary with ability in reading comprehension in Chinese children.

The genome of Mesobuthus martensii reveals a unique adaptation model of arthropods

PubMed Central

Cao, Zhijian; Yu, Yao; Wu, Yingliang; Hao, Pei; Di, Zhiyong; He, Yawen; Chen, Zongyun; Yang, Weishan; Shen, Zhiyong; He, Xiaohua; Sheng, Jia; Xu, Xiaobo; Pan, Bohu; Feng, Jing; Yang, Xiaojuan; Hong, Wei; Zhao, Wenjuan; Li, Zhongjie; Huang, Kai; Li, Tian; Kong, Yimeng; Liu, Hui; Jiang, Dahe; Zhang, Binyan; Hu, Jun; Hu, Youtian; Wang, Bin; Dai, Jianliang; Yuan, Bifeng; Feng, Yuqi; Huang, Wei; Xing, Xiaojing; Zhao, Guoping; Li, Xuan; Li, Yixue; Li, Wenxin

2013-01-01

Representing a basal branch of arachnids, scorpions are known as ‘living fossils’ that maintain an ancient anatomy and are adapted to have survived extreme climate changes. Here we report the genome sequence of Mesobuthus martensii, containing 32,016 protein-coding genes, the most among sequenced arthropods. Although M. martensii appears to evolve conservatively, it has a greater gene family turnover than the insects that have undergone diverse morphological and physiological changes, suggesting the decoupling of the molecular and morphological evolution in scorpions. Underlying the long-term adaptation of scorpions is the expansion of the gene families enriched in basic metabolic pathways, signalling pathways, neurotoxins and cytochrome P450, and the different dynamics of expansion between the shared and the scorpion lineage-specific gene families. Genomic and transcriptomic analyses further illustrate the important genetic features associated with prey, nocturnal behaviour, feeding and detoxification. The M. martensii genome reveals a unique adaptation model of arthropods, offering new insights into the genetic bases of the living fossils. PMID:24129506

Oriented clay nanopaper from biobased components--mechanisms for superior fire protection properties.

PubMed

Carosio, F; Kochumalayil, J; Cuttica, F; Camino, G; Berglund, L

2015-03-18

The toxicity of the most efficient fire retardant additives is a major problem for polymeric materials. Cellulose nanofiber (CNF)/clay nanocomposites, with unique brick-and-mortar structure and prepared by simple filtration, are characterized from the morphological point of view by scanning electron microscopy and X-ray diffraction. These nanocomposites have superior fire protection properties to other clay nanocomposites and fiber composites. The corresponding mechanisms are evaluated in terms of flammability (reaction to a flame) and cone calorimetry (exposure to heat flux). These two tests provide a wide spectrum characterization of fire protection properties in CNF/montmorrilonite (MTM) materials. The morphology of the collected residues after flammability testing is investigated. In addition, thermal and thermo-oxidative stability are evaluated by thermogravimetric analyses performed in inert (nitrogen) and oxidative (air) atmospheres. Physical and chemical mechanisms are identified and related to the unique nanostructure and its low thermal conductivity, high gas barrier properties and CNF/MTM interactions for char formation.

Synthesis of Gold Nanoparticles with Buffer-Dependent Variations of Size and Morphology in Biological Buffers.

PubMed

Ahmed, Syed Rahin; Oh, Sangjin; Baba, Rina; Zhou, Hongjian; Hwang, Sungu; Lee, Jaebeom; Park, Enoch Y

2016-12-01

The demand for biologically compatible and stable noble metal nanoparticles (NPs) has increased in recent years due to their inert nature and unique optical properties. In this article, we present 11 different synthetic methods for obtaining gold nanoparticles (Au NPs) through the use of common biological buffers. The results demonstrate that the sizes, shapes, and monodispersity of the NPs could be varied depending on the type of buffer used, as these buffers acted as both a reducing agent and a stabilizer in each synthesis. Theoretical simulations and electrochemical experiments were performed to understand the buffer-dependent variations of size and morphology exhibited by these Au NPs, which revealed that surface interactions and the electrostatic energy on the (111) surface of Au were the determining factors. The long-term stability of the synthesized NPs in buffer solution was also investigated. Most NPs synthesized using buffers showed a uniquely wide range of pH stability and excellent cell viability without the need for further modifications.

A new species of small-eared shrew of the genus Cryptotis (Mammalia, Eulipotyphla, Soricidae) from the northernmost Peruvian Andes.

PubMed

Zeballos, Horacio; Pino, Kateryn; Medina, CÉsar E; Pari, Alexander; ChÁvez, Daniel; Tinoco, NicolÁs; Ceballos, Gerardo

2018-01-31

The northernmost Peruvian Andes, a unique biogeographic region characterized by the confluence of multiple distinct ecosystems (i.e. Amazon basin, Pacific rainforest, the Sechura Desert, the northern and central Andes), is the southernmost geographic range limit of the South American shrews representing the genus Cryptotis. In the northernmost Peruvian Andes, two poorly known species have traditionally been reported (C. peruviensis and C. equatoris). Our study, based on molecular and morphologic traits, confirms the presence of C. peruviensis but also the occurrence of C. montivaga, based on specimens erroneously assigned to C. equatoris. Moreover, a new species of Cryptotis from the páramo and montane forests of the Tabaconas Namballe National Sanctuary near the Ecuadorian border is also described. It is a member of the thomasi group and is distinguished from other South American shrews by a unique set of morphological characters, including large body size, comparatively short tail, simple ectoloph of M3, and large PM4 post protocrista.

Anomalous charge transport in conjugated polymers reveals underlying mechanisms of trapping and percolation

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

Mollinger, Sonya A.; Salleo, Alberto; Spakowitz, Andrew J.

While transport in conjugated polymers has many similarities to that in crystalline inorganic materials, several key differences reveal the unique relationship between the morphology of polymer films and the charge mobility. We develop a model that directly incorporates the molecular properties of the polymer film and correctly predicts these unique transport features. At low degree of polymerization, the increase of the mobility with the polymer chain length reveals trapping at chain ends, and saturation of the mobility at high degree of polymerization results from conformational traps within the chains. Similarly, the inverse field dependence of the mobility reveals that transportmore » on single polymer chains is characterized by the ability of the charge to navigate around kinks and loops in the chain. Lastly, these insights emphasize the connection between the polymer conformations and the transport and thereby offer a route to designing improved device morphologies through molecular design and materials processing.« less

Anomalous charge transport in conjugated polymers reveals underlying mechanisms of trapping and percolation

DOE PAGES

Mollinger, Sonya A.; Salleo, Alberto; Spakowitz, Andrew J.

2016-11-10

While transport in conjugated polymers has many similarities to that in crystalline inorganic materials, several key differences reveal the unique relationship between the morphology of polymer films and the charge mobility. We develop a model that directly incorporates the molecular properties of the polymer film and correctly predicts these unique transport features. At low degree of polymerization, the increase of the mobility with the polymer chain length reveals trapping at chain ends, and saturation of the mobility at high degree of polymerization results from conformational traps within the chains. Similarly, the inverse field dependence of the mobility reveals that transportmore » on single polymer chains is characterized by the ability of the charge to navigate around kinks and loops in the chain. Lastly, these insights emphasize the connection between the polymer conformations and the transport and thereby offer a route to designing improved device morphologies through molecular design and materials processing.« less

Coupling scanning tunneling microscope and supersonic molecular beams: a unique tool for in situ investigation of the morphology of activated systems.

PubMed

Smerieri, M; Reichelt, R; Savio, L; Vattuone, L; Rocca, M

2012-09-01

We report here on a new experimental apparatus combining a commercial low temperature scanning tunneling microscope with a supersonic molecular beam. This setup provides a unique tool for the in situ investigation of the topography of activated adsorption systems and opens thus new interesting perspectives. It has been tested towards the formation of the O/Ag(110) added rows reconstruction and of their hydroxylation, comparing data recorded upon O(2) exposure at thermal and hyperthermal energies.

The Predentary Bone and Its Significance in the Evolution of Feeding Mechanisms in Ornithischian Dinosaurs.

PubMed

Nabavizadeh, Ali; Weishampel, David B

2016-10-01

The characteristic predentary bone in ornithischian dinosaurs is a unique, unpaired element located at the midline of the mandibular symphysis. Although traditionally thought to only be a plant "nipping" bone, the true functional significance of this bone among feeding mechanisms of ornithischian dinosaurs is poorly known. Recent studies of a select few ornithischian genera have suggested rotation of the mandibular corpora around their long axes relative to their midline joint articulation with the predentary bone. This study aims to re-evaluate these hypotheses as well as provide in-depth qualitative comparative descriptions of predentary bone morphology in ornithischian genera throughout all subclades, including heterodontosaurids, thyreophorans, ornithopods, and marginocephalians. Descriptions evaluate overall shape of the predentary, its articular surfaces contacting the rostral ends of the dentaries, and the morphology of the rostral extent of the dentaries and their midline symphysis. Functionally relevant morphologies in each predentary morphotype are accentuated for further speculation of feeding mechanisms. Three predentary morphotypes are described throughout ornithischian subclades and each plays a unique role in feeding adaptations. Most notably, the predentary likely evolved as a midline axial point of the mandibular symphysis for simultaneous variable movement or rotation of the mandibular corpora in many, but not all, taxa. This simultaneous movement of the hemimandibles would have aided in feeding on both sides of the jaw at once. The function of the predentary as well as other jaw adaptations is discussed for genera throughout all subclades, focusing on both general shape and joint morphology. Anat Rec, 299:1358-1388, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Etude du champ magnetique dans les nuages moleculaires

NASA Astrophysics Data System (ADS)

Houde, Martin

2001-12-01

Ce travail est une étude du champ magnétique duns l'environnement circumstellaire des étoiles jeunes. Il a pour origine la certitude qu'avait l'auteur qu'il se devait d'être possible de détecter la présence d'un champ magnétique, et de possiblement le caractériser, par le biais d'observations de profils spectraux d'espèces moléculaires ioniques. Il en découle donc qu'un des buts principaux était de prouver que cela est effectivement possible. La thèse comporte alors des éléments théoriques et expérimentaux qui sont à la fois complémentaires et intimement liés. L'aspect théorique est basé sur l'interaction mutuelle que des particules neutres et chargées peuvent avoir l'une sur l'autre daps un plasma faiblement ionisé comme ceux existants daps les nuages moléculaires sites de formation stellaire. Il appert que la présence d'un champ magnétique a un effet direct sur le comportement des ions (via la force de Lorentz) et indirect sur les molécules neutres (via les nombreuses collisions entre les deux types de particules). Une telle interaction est, comme il est maintenant bien connu, présente dans les premières étapes de la formation dune étoile. Il s'agit bien sûr de la diffusion ambipolaire. Nous montrerons qu'il existe cependant un autre type de diffusion, jusqu'ici inconnue, qui se manifeste plus tard au tours de l'évolution des nuages moléculaires. Celle-ci peut avoir un effet dramatique sur l'apparence des profils spectraux (de rotation moléculaire) des espèces ioniques lorsque comparés à ceux qu'exhibent des espèces neutres coexistantes. Mais pour ce faire, il doit y avoir existence de mouvements organisés (des flots ou jets) de matière ou encore la présence de turbulence dans les régions considérées. Une distribution de vélocité du type maxwellienne ne révèlera pas la présence du champ magnétique. Les observations, qui ont pour but de confirmer la théorie, se situent dans le domaine des longueurs d'ondes millimétriques et sous- millimétriques. Plusieurs espèces moléculaires furent détectées dans un échantillon significatif de nuages moléculaires. L'effet prédit fut confirmé et ce peu importe si les raies observées sont opaques ou transparentes. Dans le dernier chapitre, nous considérerons une application intéressante où nous utiliserons la manifestation de cet effet (ou son manque) pour vérifier l'alignement préférentiel des flots bipolaires, qui accompagnent souvent la présence de proto- étoiles, avec le champ magnétique local.

Verbal Complementizers in Arabic

ERIC Educational Resources Information Center

Ahmed, Hossam Eldin Ibrahim

2015-01-01

A class of Modern Standard Arabic complementizers known as "'?inna' and its sisters" demonstrate unique case and word order restrictions. While CPs in Arabic allow both Subject-Verb (SV) and Verb-Subject (VS) word order and their subjects show nominative morphology, CPs introduced by "?inna" ban a verb from directly following…

Classification and phylogenetic analysis of Chinese hawthorn assessed by plant and pollen morphology.

PubMed

Ma, S L Y; Lu, Y M

2016-09-19

The Chinese hawthorn (Crataegus pinnatifida Bge. var. major N.E.Br.) is uniquely originated in northern China. The ecological and horticultural importance of Chinese hawthorn is considerable and some varieties are valued for their fruit or medicine extracts. Its taxonomy and phylogeny remain poorly understood. Apart from general plant morphological traits, pollen is an important trait for the classification of plants and their evolutionary origin. However, few studies have investigated the pollen of Chinese hawthorn. Here, an analysis of plant and pollen morphological characteristics was conducted in 57 cultivars from the Shenyang region. Thirty plant morphological characters and nine pollen grain characters were investigated. The plant morphological analysis revealed that the coefficient of variation for 13 traits was >20%, which indicates a high degree of variability. We also found that the pollen grains varied greatly in size, shape (from prolate to perprolate), and exine pattern (striate-perforate predominantly). The number of apertures was typically three. Based on these findings, we suggest that pollen morphology associated with plant morphological traits can be used for classification and phylogenetic analysis of Chinese hawthorn cultivars. In sum, our results provide new insights and constitute a scientific basis for future studies on the classification and evolution of Chinese hawthorn.

Tinea pedis presenting as asymmetric purpuric papules on the sole of the foot: a case report.

PubMed

Chen, Jennifer Yan Fei; Stroz, Marianne J; Adam, David N

2015-01-01

In this report we describe a unique case of tinea pedis. A 29-year-old man presented with a 3-day history of asymptomatic purpuric papules predominantly on his left foot. Potassium hydroxide preparation demonstrated fungal hyphae and culture yielded Trichophyton mentagrophytes. This patient presented unusually with purpuric papules, unlike the three commonly described types of tinea pedis. Given the morphology, positive potassium hydroxide slide preparation, T. mentagrophytes on fungal culture and clinical response to ketoconazole cream, we conclude that this represents a unique variant of tinea pedis. We recognize that even common dermatological diagnoses can have unique presentations, and it is important for clinicians to maintain a broad differential for new dermatologic cases.

Tinea Pedis Presenting as Asymmetric Purpuric Papules on the Sole of the Foot: A Case Report

PubMed Central

Chen, Jennifer Yan Fei; Stroz, Marianne J.; Adam, David N.

2015-01-01

In this report we describe a unique case of tinea pedis. A 29-year-old man presented with a 3-day history of asymptomatic purpuric papules predominantly on his left foot. Potassium hydroxide preparation demonstrated fungal hyphae and culture yielded Trichophyton mentagrophytes. This patient presented unusually with purpuric papules, unlike the three commonly described types of tinea pedis. Given the morphology, positive potassium hydroxide slide preparation, T. mentagrophytes on fungal culture and clinical response to ketoconazole cream, we conclude that this represents a unique variant of tinea pedis. We recognize that even common dermatological diagnoses can have unique presentations, and it is important for clinicians to maintain a broad differential for new dermatologic cases. PMID:25873874

Hollow Mesoporous Carbon Microparticles and Micromotors with Single Holes Templated by Colloidal Silica-Assisted Gas Bubbles.

PubMed

Huang, Xiaoxi; Zhang, Tao; Asefa, Tewodros

2017-07-01

A simple, new synthetic method that produces hollow, mesoporous carbon microparticles, each with a single hole on its surface, is reported. The synthesis involves unique templates, which are composed of gaseous bubbles and colloidal silica, and poly(furfuryl alcohol) as a carbon precursor. The conditions that give these morphologically unique carbon microparticles are investigated, and the mechanisms that result in their unique structures are proposed. Notably, the amount of colloidal silica and the type of polymer are found to hugely dictate whether or not the synthesis results in hollow asymmetrical microparticles, each with a single hole. The potential application of the particles as self-propelled micromotors is demonstrated. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultra-high density aligned Carbon-nanotube with controled nano-morphology for supercapacitors

NASA Astrophysics Data System (ADS)

Ghaffari, Mehdi; Zhao, Ran; Liu, Yang; Zhou, Yue; Cheng, Jiping; Guzman de Villoria, Roberto; Wardle, B. L.; Zhang, Q. M.

2012-02-01

Recent advances in fabricating controlled-morphology vertically aligned carbon nanotubes (VA-CNTs) with ultrahigh volume fractioncreate unique opportunities for developing unconventional supercapacitors with ultra-high energy density, power density, and long charge/discharge cycle life.Continuous paths through inter-VA-CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast discharge speed. We investigate the charge-discharge characteristics of VA-CNTs with >20 vol% of CNT and ionic liquids as electrolytes. By employing both the electric and electromechanical spectroscopes, as well as nanostructured materials characterization, the ion transport and storage behaviors in porous electrodes are studied. The results suggest pathways for optimizing the electrode morphology in supercapacitorsusing ultra-high volume fraction VA-CNTs to further enhance performance.

Pervasive influence of idiosyncratic associative biases during facial emotion recognition.

PubMed

El Zein, Marwa; Wyart, Valentin; Grèzes, Julie

2018-06-11

Facial morphology has been shown to influence perceptual judgments of emotion in a way that is shared across human observers. Here we demonstrate that these shared associations between facial morphology and emotion coexist with strong variations unique to each human observer. Interestingly, a large part of these idiosyncratic associations does not vary on short time scales, emerging from stable inter-individual differences in the way facial morphological features influence emotion recognition. Computational modelling of decision-making and neural recordings of electrical brain activity revealed that both shared and idiosyncratic face-emotion associations operate through a common biasing mechanism rather than an increased sensitivity to face-associated emotions. Together, these findings emphasize the underestimated influence of idiosyncrasies on core social judgments and identify their neuro-computational signatures.

Giraffe genome sequence reveals clues to its unique morphology and physiology

PubMed Central

Agaba, Morris; Ishengoma, Edson; Miller, Webb C.; McGrath, Barbara C.; Hudson, Chelsea N.; Bedoya Reina, Oscar C.; Ratan, Aakrosh; Burhans, Rico; Chikhi, Rayan; Medvedev, Paul; Praul, Craig A.; Wu-Cavener, Lan; Wood, Brendan; Robertson, Heather; Penfold, Linda; Cavener, Douglas R.

2016-01-01

The origins of giraffe's imposing stature and associated cardiovascular adaptations are unknown. Okapi, which lacks these unique features, is giraffe's closest relative and provides a useful comparison, to identify genetic variation underlying giraffe's long neck and cardiovascular system. The genomes of giraffe and okapi were sequenced, and through comparative analyses genes and pathways were identified that exhibit unique genetic changes and likely contribute to giraffe's unique features. Some of these genes are in the HOX, NOTCH and FGF signalling pathways, which regulate both skeletal and cardiovascular development, suggesting that giraffe's stature and cardiovascular adaptations evolved in parallel through changes in a small number of genes. Mitochondrial metabolism and volatile fatty acids transport genes are also evolutionarily diverged in giraffe and may be related to its unusual diet that includes toxic plants. Unexpectedly, substantial evolutionary changes have occurred in giraffe and okapi in double-strand break repair and centrosome functions. PMID:27187213

Morphological Integration of Soft-Tissue Facial Morphology in Down Syndrome and Siblings

PubMed Central

Starbuck, John; Reeves, Roger H.; Richtsmeier, Joan

2011-01-01

Down syndrome (DS), resulting from trisomy of chromosome 21, is the most common live-born human aneuploidy. The phenotypic expression of trisomy 21 produces variable, though characteristic, facial morphology. Although certain facial features have been documented quantitatively and qualitatively as characteristic of DS (e.g., epicanthic folds, macroglossia, and hypertelorism), all of these traits occur in other craniofacial conditions with an underlying genetic cause. We hypothesize that the typical DS face is integrated differently than the face of non-DS siblings, and that the pattern of morphological integration unique to individuals with DS will yield information about underlying developmental associations between facial regions. We statistically compared morphological integration patterns of immature DS faces (N = 53) with those of non-DS siblings (N = 54), aged 6–12 years using 31 distances estimated from 3D coordinate data representing 17 anthropometric landmarks recorded on 3D digital photographic images. Facial features are affected differentially in DS, as evidenced by statistically significant differences in integration both within and between facial regions. Our results suggest a differential affect of trisomy on facial prominences during craniofacial development. PMID:21996933

Morphological integration of soft-tissue facial morphology in Down Syndrome and siblings.

PubMed

Starbuck, John; Reeves, Roger H; Richtsmeier, Joan

2011-12-01

Down syndrome (DS), resulting from trisomy of chromosome 21, is the most common live-born human aneuploidy. The phenotypic expression of trisomy 21 produces variable, though characteristic, facial morphology. Although certain facial features have been documented quantitatively and qualitatively as characteristic of DS (e.g., epicanthic folds, macroglossia, and hypertelorism), all of these traits occur in other craniofacial conditions with an underlying genetic cause. We hypothesize that the typical DS face is integrated differently than the face of non-DS siblings, and that the pattern of morphological integration unique to individuals with DS will yield information about underlying developmental associations between facial regions. We statistically compared morphological integration patterns of immature DS faces (N = 53) with those of non-DS siblings (N = 54), aged 6-12 years using 31 distances estimated from 3D coordinate data representing 17 anthropometric landmarks recorded on 3D digital photographic images. Facial features are affected differentially in DS, as evidenced by statistically significant differences in integration both within and between facial regions. Our results suggest a differential affect of trisomy on facial prominences during craniofacial development. 2011 Wiley Periodicals, Inc.

Multisyllabic Word Reading as a Moderator of Morphological Awareness and Reading Comprehension

PubMed Central

Gilbert, Jennifer K.; Goodwin, Amanda P.; Compton, Donald L.; Kearns, Devin M.

2013-01-01

The purpose of this study was to investigate whether the relation between morphological awareness on reading comprehension is moderated by multisyllabic word reading ability in fifth grade students (N = 169, 53.7% female, 65.2% minority status, 69.2% free/reduced lunch status), oversampled for poor reading skill, when controlling for general knowledge and vocabulary. Based on the lexical quality hypothesis (Perfetti, 2007), it was expected that morphological awareness would have a stronger effect on comprehension for children with poor word reading skills, suggesting possible use of morphological awareness for word identification support. Results indicated that neither morphological awareness nor word reading was uniquely associated with reading comprehension when both were included in the model along with vocabulary and general knowledge. Instead, the interaction between word reading and morphological awareness explained significant additional variance in reading comprehension. By probing this interaction, it was determined that the effect of morphological awareness on reading comprehension was significant for the 39% of the sample that had more difficulty reading multisyllabic words), but not for students at the higher end of the multisyllabic word reading continuum. We conclude from these results that the relation between morphological awareness and reading comprehension is moderated by multisyllabic word reading ability, providing support for the lexical quality hypothesis (Perfetti, 2007). Although we have only correlational data, we suggest tentative instructional practices for improving the reading skill of upper elementary struggling readers. PMID:24219914

Teeth and numerology from zodiac signs. A correlative study.

PubMed

Kudva, S; Bhat, A P

2000-01-01

Comparative anatomical descriptions have been time and again mentioned in the literature. Based on these aspects, an attempt is made to correlate the morphological features of the human teeth, the zodiac sun signs and numerology. This unique study (first ever of its kind) is also done with a purpose as to whether a particular 'Zodiac Sunsign' or numerology can predict about an individual dental health, the same way the future predictions are being made. It was quite interesting to note that there are few definite attributable dental morphological traits and health to the specific sun signs and numerology.

A new species of the sponge Raspailia (Raspaxilla) (Porifera: Demospongiae: Axinellida: Raspailiidae) from deep seamounts of the Western Pacific.

PubMed

Ekins, Merrick; Debitus, CÉcile; Erpenbeck, Dirk; Hooper, John N A

2018-04-17

A new species of Raspailia (Raspaxilla) frondosa sp. nov. is described from the deep seamounts of the Norfolk and New Caledonia Ridges. The morphology of the species resembles that of a frond or a fern, and its unique highly compressed axial skeleton of interlaced spongin fibres without spicules in combination with a radial extra axial skeleton of a perpendicular palisade of spicules, differentiate it from all other species of the subgenus. This species is compared morphologically to all 18 other valid species described in Raspailia (Raspaxilla).

Motion Cues in Flight Simulation and Simulator Induced Sickness

DTIC Science & Technology

1988-06-01

asseusod in a driving simulator by means of a response surface methodology central-composite design . The most salient finding of the study was that visual...across treatment conditions. For an orthogonal response surface methodology (IBM) design with only tro independent variables. it can be readily shown that...J.E.Fowikes 8 SESSION III - ETIOLOGICAL FACTORS IN SIMULATOR-INDUCED AFTER EFFETS THE USE OF VE& IIBULAR MODELS FOR DESIGN AND EVALUATION OF FLIGHT

Engineering Aerodynamics

DTIC Science & Technology

1986-12-01

effective Reynolds Number5 to include the effet Of turbulence, which was supported in a convincing manner by the same ratio of 2.4 betwveen the Reynolds...iLIFT DEVICIS 143 methods incorl)orating various forms of flas) are shown on Figure 59. The other two methods, Boundary Layer Control and the Magnus ...Class Airship Hlull with Varying Lengths of Cylindric Midships," N.A.CA. Technical Report No. 138 (1922). 276 ENGINEERING AERODYNAMICS [Ch. 9 -- - - 2.0

Environmental Exposure and Design Criteria for Offshore Oil and Gas Structures

DTIC Science & Technology

1980-05-01

reliability ar_alysis. Because there are no clear lines of demarcation between them, these methods are often used in varying combinations. Sound ...cludes that OCSEA-P not now effe.tively contribute...to the accrual of sound scientific information adequate for OCS management." One reason for such a...procedures for resolving differences need to be developed. Sound and timely assessments of environmental exposure risks will require: 1) adequate levels of

A Snowball's Chance? Communities and Families Working To Prevent Youth Crime = Effet de boule de neige? Les communautes et les familles collaborent a la prevention de la criminalite chez les jeunes.

ERIC Educational Resources Information Center

Theilheimer, Ish, Ed.; Eisner, Kathy, Ed.

1996-01-01

This issue of the Canadian quarterly "Transitions," in French and English language versions, examines the prevention of youth crime, with a specific focus on activities, trends, and research dealing with Canadian families. Major articles in this issue are: (1) "A Snowball's Chance? Communities and Families Working to Prevent Youth…

Superomniphobic Surfaces for Military Applications: Nano- and Micro-Fabrication Methods. Chapter 1: Lithographic Fabrication of Surfaces with Different Microgeometries and Investigation of Their Wetting Behaviour

DTIC Science & Technology

2011-01-01

plus important, comparativement à une échelle plus large. Les résultats indiquent qu’un effet de cette nature est attribuable à des facteurs...par un angle de contact à l’avancement plus petit et un angle de contact au retrait plus important, comparativement à une échelle plus large. Les...Methods ............................................................................................................ 10 3.1 Experimental Design

Recherche universitaire et priorites nationales: l'effet du financement public sur la recherche energie solaire au Canada (University Research and National Priorities: The Effect of Public Financing on Solar Energy Research in Canada).

ERIC Educational Resources Information Center

Dalpe, Robert; Gingras, Yves

1990-01-01

The role of two main sources of university research financing in solar energy is examined to assess whether they oriented research in the direction of government programs. The strongest relationship appears to be in journal publication patterns. This scientific community has acquired the capacity to tap varying sources. (Author/MSE)

Mechanized Symmetrical Sowing

Treesearch

Kirk D. Howell

2005-01-01

With hundreds of variables to investigate, and thousands of combinations, seldom is there found such appeal to the investigator as an organism’s response to density. Loblolly pine (Pinus taeda L.) was grown at several levels of seedbed density and sowing configurations in order to display unique contrasts between consequent morphological traits,...

Allantoin crystal formation in Bagrada hilaris (Burmeister)(Hemiptera: Pentatomidae) females

USDA-ARS?s Scientific Manuscript database

Bagrada hilaris is a polyphagous herbivore recently reported as an invasive pest in the U.S. During the course of dissecting B. hilaris to understand ovarian morphology in relation to egg production and to determine sperm viability, unique crystals were observed in both the midgut and oviducts. Cry...

Executive Functioning Skills Uniquely Predict Chinese Word Reading

ERIC Educational Resources Information Center

Chung, Kevin K. H.; McBride-Chang, Catherine

2011-01-01

Eighty-five Hong Kong Chinese children were tested across both the 2nd and 3rd years of kindergarten (ages 4-5 years) on tasks of inhibitory control, working memory, vocabulary knowledge, phonological awareness, morphological awareness, and word reading. With age, vocabulary knowledge, and metalinguistic skills statistically controlled, the…

Allantoin crystal formation in Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae) females

USDA-ARS?s Scientific Manuscript database

Bagrada hilaris is a polyphagous herbivore recently reported as an invasive pest in the U.S. During the course of dissecting B. hilaris to understand ovarian morphology in relation to egg production and to determine sperm viability, unique crystals were observed in both the midgut and oviducts. Crys...

Slope-Velocity-Equilibrium and evolution of surface roughness on a stony hillslope

USDA-ARS?s Scientific Manuscript database

Slope-velocity equilibrium is hypothesized as a state that evolves naturally over time due to the interaction between overland flow and bed morphology, wherein steeper areas develop a relative increase in physical and hydraulic roughness such that flow velocity is a unique function of overland flow ...

Complex coevolutionary history of symbiotic Bacteroidales bacteria of various protists in the gut of termites

PubMed Central

Noda, Satoko; Hongoh, Yuichi; Sato, Tomoyuki; Ohkuma, Moriya

2009-01-01

Background The microbial community in the gut of termites is responsible for the efficient decomposition of recalcitrant lignocellulose. Prominent features of this community are its complexity and the associations of prokaryotes with the cells of cellulolytic flagellated protists. Bacteria in the order Bacteroidales are involved in associations with a wide variety of gut protist species as either intracellular endosymbionts or surface-attached ectosymbionts. In particular, ectosymbionts exhibit distinct morphological patterns of the associations. Therefore, these Bacteroidales symbionts provide an opportunity to investigate not only the coevolutionary relationships with the host protists and their morphological evolution but also how symbiotic associations between prokaryotes and eukaryotes occur and evolve within a complex symbiotic community. Results Molecular phylogeny of 31 taxa of Bacteroidales symbionts from 17 protist genera in 10 families was examined based on 16S rRNA gene sequences. Their localization, morphology, and specificity were also examined by fluorescent in situ hybridizations. Although a monophyletic grouping of the ectosymbionts occurred in three related protist families, the symbionts of different protist genera were usually dispersed among several phylogenetic clusters unique to termite-gut bacteria. Similar morphologies of the associations occurred in multiple lineages of the symbionts. Nevertheless, the symbionts of congeneric protist species were closely related to one another, and in most cases, each host species harbored a unique Bacteroidales species. The endosymbionts were distantly related to the ectosymbionts examined so far. Conclusion The coevolutionary history of gut protists and their associated Bacteroidales symbionts is complex. We suggest multiple independent acquisitions of the Bacteroidales symbionts by different protist genera from a pool of diverse bacteria in the gut community. In this sense, the gut could serve as a reservoir of diverse bacteria for associations with the protist cells. The similar morphologies are considered a result of evolutionary convergence. Despite the complicated evolutionary history, the host-symbiont relationships are mutually specific, suggesting their cospeciations at the protist genus level with only occasional replacements. PMID:19586555

Tempo and mode of performance evolution across multiple independent origins of adhesive toe pads in lizards.

PubMed

Hagey, Travis J; Uyeda, Josef C; Crandell, Kristen E; Cheney, Jorn A; Autumn, Kellar; Harmon, Luke J

2017-10-01

Understanding macroevolutionary dynamics of trait evolution is an important endeavor in evolutionary biology. Ecological opportunity can liberate a trait as it diversifies through trait space, while genetic and selective constraints can limit diversification. While many studies have examined the dynamics of morphological traits, diverse morphological traits may yield the same or similar performance and as performance is often more proximately the target of selection, examining only morphology may give an incomplete understanding of evolutionary dynamics. Here, we ask whether convergent evolution of pad-bearing lizards has followed similar evolutionary dynamics, or whether independent origins are accompanied by unique constraints and selective pressures over macroevolutionary time. We hypothesized that geckos and anoles each have unique evolutionary tempos and modes. Using performance data from 59 species, we modified Brownian motion (BM) and Ornstein-Uhlenbeck (OU) models to account for repeated origins estimated using Bayesian ancestral state reconstructions. We discovered that adhesive performance in geckos evolved in a fashion consistent with Brownian motion with a trend, whereas anoles evolved in bounded performance space consistent with more constrained evolution (an Ornstein-Uhlenbeck model). Our results suggest that convergent phenotypes can have quite distinctive evolutionary patterns, likely as a result of idiosyncratic constraints or ecological opportunities. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Two new Bent-toed Geckos of the Cyrtodactylus pulchellus complex from Peninsular Malaysia and multiple instances of convergent adaptation to limestone forest ecosystems.

PubMed

Grismer, L Lee; Wood, Perry L; Anuar, Shahrul; Grismer, Marta S; Quah, Evan S H; Murdoch, Matthew L; Muin, Mohd Abdul; Davis, Hayden R; Aguilar, César; Klabacka, Randy; Cobos, Anthony J; Aowphol, Anchalee; Sites, Jack W

2016-04-25

A new species of limestone cave-adapted gecko of the Cyrtodactylus pulchellus complex, C. hidupselamanya sp. nov., is described from an isolated karst formation at Felda Chiku 7, Kelantan, Peninsular Malaysia. This formation is scheduled to be completely quarried for its mineral content. From what we know about the life history of C. hidupselamanya sp. nov., this will result in its extinction. A new limestone forest-adapted species, C. lenggongensis sp. nov., from the Lenggong Valley, Perak was previously considered to be conspecific with C. bintangrendah but a re-evaluation of morphological, color pattern, molecular, and habitat preference indicates that it too is a unique lineage worthy of specific recognition. Fortunately C. lenggongensis sp. nov. is not facing extinction because its habitat is protected by the UNESCO Archaeological Heritage of the Lenggong Valley due to the archaeological significance of that region. Both new species can be distinguished from all other species of Cyrtodactylus based on molecular evidence from the mitochondrial gene ND2 and its flanking tRNAs as well as having unique combinations of morphological and color pattern characteristics. Using a time-calibrated BEAST analysis we inferred that the evolution of a limestone habitat preference and its apparently attendant morphological and color pattern adaptations evolved independently at least four times in the C. pulchellus complex between 26.1 and 0.78 mya.

Mouse spermatozoa with higher fertilization rates have thinner nuclei

PubMed Central

Ikawa, Masahito

2017-01-01

Background Although spermatozoa with normal morphology are assumed to have uniform fertilization ability, recent data show that even normal spermatozoa have considerable variation in their head shape which is associated with differences in fertilization ability. Appropriate quantitative indicators for good sperm morphology, however, remain unidentified. Methods Therefore, in an effort to identify such an indicator, we compared the nuclear contour of normal mouse spermatozoa by quantitative multivariate analysis using elliptic Fourier descriptors combined with principal component analysis. The spermatozoa were obtained from different strains and collection sites which have been shown to be associated with different fertilization abilities. Results We found that the head was 5.7% thinner in spermatozoa from the B6D2F1 (BDF1) strain, known to have a higher fertilization rate, than in those from the C57BL/6N (B6N) strain, which has a lower fertilization rate. Moreover, zona-penetrated spermatozoa in the perivitelline space consistently had 5.4% thinner heads than those isolated from the epididymis before ejaculation. The aspect ratio, which represents the sperm head thinness, uniquely distinguished these sperm populations, confirming its validity as a morphological indicator. Discussion Because aspect ratio has also been shown to characterize human spermatozoa, this unique morphometric indicator might be applicable to compare normal spermatozoa among multiple patients, which will greatly facilitate and enhance current reproductive technologies. PMID:29038763

Characteristics of zircons from volcanic ash-derived tonsteins in Late Permian coal fields of eastern Yunnan, China

USGS Publications Warehouse

Zhou, Y.; Ren, Y.; Tang, D.; Bohor, B.

1994-01-01

Kaolinitic tonsteins of altered synsedimentary volcanic ash-fall origin are well developed in the Late Permian coal-bearing formations of eastern Yunnan Province. Because of their unique origin, wide lateral extent, relatively constant thickness and sharp contacts with enclosing strata, great importance has been attached to these isochronous petrographic markers. In order to compare tonsteins with co-existing, non-cineritic claystones and characterize the individuality of tonsteins from different horizons for coal bed correlation, a semi-quantitative method was developed that is based on statistical analyses of the concentration and morphology of zircons and their spatial distribution patterns. This zircon-based analytical method also serves as a means for reconstructing volcanic ash-fall dispersal patterns. The results demonstrate that zircons from claystones of two different origins (i.e., tonstein and non-cineritic claystone) differ greatly in their relative abundances, crystal morphologies and spatial distribution patterns. Tonsteins from the same area but from different horizons are characterized by their own unique statistical patterns in terms of zircon concentration values and morphologic parameters (crystal length, width and the ratio of these values), thus facilitating stratigraphic correlation. Zircons from the same tonstein horizon also show continuous variation in these statistical patterns as a function of areal distribution, making it possible to identify the main path and direction in which the volcanic source materials were transported by prevailing winds. ?? 1994.

Nematogalectin, a nematocyst protein with GlyXY and galectin domains, demonstrates nematocyte-specific alternative splicing in Hydra

PubMed Central

Hwang, Jung Shan; Takaku, Yasuharu; Momose, Tsuyoshi; Adamczyk, Patrizia; Özbek, Suat; Ikeo, Kazuho; Khalturin, Konstantin; Hemmrich, Georg; Bosch, Thomas C. G.; Holstein, Thomas W.; David, Charles N.; Gojobori, Takashi

2010-01-01

Taxonomically restricted genes or lineage-specific genes contribute to morphological diversification in metazoans and provide unique functions for particular taxa in adapting to specific environments. To understand how such genes arise and participate in morphological evolution, we have investigated a gene called nematogalectin in Hydra, which has a structural role in the formation of nematocysts, stinging organelles that are unique to the phylum Cnidaria. Nematogalectin is a 28-kDa protein with an N-terminal GlyXY domain (glycine followed by two hydrophobic amino acids), which can form a collagen triple helix, followed by a galactose-binding lectin domain. Alternative splicing of the nematogalectin transcript allows the gene to encode two proteins, nematogalectin A and nematogalectin B. We demonstrate that expression of nematogalectin A and B is mutually exclusive in different nematocyst types: Desmonemes express nematogalectin B, whereas stenoteles and isorhizas express nematogalectin B early in differentiation, followed by nematogalectin A. Like Hydra, the marine hydrozoan Clytia also has two nematogalectin transcripts, which are expressed in different nematocyte types. By comparison, anthozoans have only one nematogalectin gene. Gene phylogeny indicates that tandem duplication of nematogalectin B exons gave rise to nematogalectin A before the divergence of Anthozoa and Medusozoa and that nematogalectin A was subsequently lost in Anthozoa. The emergence of nematogalectin A may have played a role in the morphological diversification of nematocysts in the medusozoan lineage. PMID:20937891

Isotropic and Anisotropic Growth of Metal-Organic Framework (MOF) on MOF: Logical Inference on MOF Structure Based on Growth Behavior and Morphological Feature.

PubMed

Choi, Sora; Kim, Taeho; Ji, Hoyeon; Lee, Hee Jung; Oh, Moonhyun

2016-11-02

The growth of one metal-organic framework (MOF) on another MOF for constructing a heterocompositional hybrid MOF is an interesting research topic because of the curiosity regarding the occurrence of this phenomenon and the value of hybrid MOFs as multifunctional materials or routes for fine-tuning MOF properties. In particular, the anisotropic growth of MOF on MOF is fascinating for the development of MOFs possessing atypical shapes and heterostructures or abnormal properties. Herein, we clarify the understanding of growth behavior of a secondary MOF on an initial MOF template, such as isotropic or anisotropic ways associated with their cell parameters. The isotropic growth of MIL-68-Br on the MIL-68 template results in the formation of core-shell-type MIL-68@MIL-68-Br. However, the unique anisotropic growth of a secondary MOF (MOF-NDC) on the MIL-68 template results in semitubular particles, and structural features of this unknown secondary MOF are successfully speculated for the first time on the basis of its unique growth behavior and morphological characteristics. Finally, the validation of this structural speculation is verified by the powder X-ray diffraction and the selected area electron diffraction studies. The results suggests that the growth behavior and morphological features of MOFs should be considered to be important factors for understanding the MOFs' structures.

Morphological changes in the cellulose and lignin components of biomass occur at different stages of steam pretreatment

DOE PAGES

Pingali, Sai Venkatesh; O'Neill, Hugh Michael; Nishiyama, Yoshiharu; ...

2014-01-09

Morphological changes to the different components of lignocellulosic biomass were observed as they occurred during steam pretreatment by placing a pressure reaction cell in a neutron beam and collecting time-resolved neutron scattering data. Changes to cellulose morphology occurred mainly in the heating phase, whereas changes in lignin morphology occurred mainly in the holding and cooling phases. During the heating stage, water is irreversibly expelled from cellulose microfibrils as the elementary fibrils coalesce. During the holding phase lignin aggregates begin to appear and they increase in size most noticeably during the cooling phase. This experiment demonstrates the unique information that inmore » situ small angle neutron scattering studies of pretreatment can provide. This approach is potentially useful in optimizing the heating, holding and cooling stages of pretreatments to allow the exact size and nature of lignin aggregates to be controlled in order to enhance enzyme accessibility to cellulose and therefore the efficiency of biomass conversion.« less

Astragalar Morphology of Selected Giraffidae

PubMed Central

2016-01-01

The artiodactyl astragalus has been modified to exhibit two trochleae, creating a double pullied structure allowing for significant dorso-plantar motion, and limited mediolateral motion. The astragalus structure is partly influenced by environmental substrates, and correspondingly, morphometric studies can yield paleohabitat information. The present study establishes terminology and describes detailed morphological features on giraffid astragali. Each giraffid astragalus exhibits a unique combination of anatomical characteristics. The giraffid astragalar morphologies reinforce previously established phylogenetic relationships. We find that the enlargement of the navicular head is a feature shared by all giraffids, and that the primitive giraffids possess exceptionally tall astragalar heads in relation to the total astragalar height. The sivatheres and the okapi share a reduced notch on the lateral edge of the astragalus. We find that Samotherium is more primitive in astragalar morphologies than Palaeotragus, which is reinforced by tooth characteristics and ossicone position. Diagnostic anatomical characters on the astragalus allow for giraffid species identifications and a better understanding of Giraffidae. PMID:27028515

Nitrogen stress triggered biochemical and morphological changes in the microalgae Scenedesmus sp. CCNM 1077.

PubMed

Pancha, Imran; Chokshi, Kaumeel; George, Basil; Ghosh, Tonmoy; Paliwal, Chetan; Maurya, Rahulkumar; Mishra, Sandhya

2014-03-01

The aim of present study was to investigate the effects of nitrogen limitation as well as sequential nitrogen starvation on morphological and biochemical changes in Scenedesmus sp. CCNM 1077. The results revealed that the nitrogen limitation and sequential nitrogen starvation conditions significantly decreases the photosynthetic activity as well as crude protein content in the organism, while dry cell weight and biomass productivity are largely unaffected up to nitrate concentration of about 30.87mg/L and 3 days nitrate limitation condition. Nitrate stress was found to have a significant effect on cell morphology of Scenedesmus sp. CCNM 1077. Total removal of nitrate from the growth medium resulted in highest lipid (27.93%) and carbohydrate content (45.74%), making it a potential feed stock for biodiesel and bio-ethanol production. This is a unique approach to understand morphological and biochemical changes in freshwater microalgae under nitrate limitation as well as sequential nitrate removal conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sloppy morphological tuning in identified neurons of the crustacean stomatogastric ganglion

PubMed Central

Otopalik, Adriane G; Goeritz, Marie L; Sutton, Alexander C; Brookings, Ted; Guerini, Cosmo; Marder, Eve

2017-01-01

Neuronal physiology depends on a neuron’s ion channel composition and unique morphology. Variable ion channel compositions can produce similar neuronal physiologies across animals. Less is known regarding the morphological precision required to produce reliable neuronal physiology. Theoretical studies suggest that moraphology is tightly tuned to minimize wiring and conduction delay of synaptic events. We utilize high-resolution confocal microscopy and custom computational tools to characterize the morphologies of four neuron types in the stomatogastric ganglion (STG) of the crab Cancer borealis. Macroscopic branching patterns and fine cable properties are variable within and across neuron types. We compare these neuronal structures to synthetic minimal spanning neurite trees constrained by a wiring cost equation and find that STG neurons do not adhere to prevailing hypotheses regarding wiring optimization principles. In this highly modulated and oscillating circuit, neuronal structures appear to be governed by a space-filling mechanism that outweighs the cost of inefficient wiring. DOI: http://dx.doi.org/10.7554/eLife.22352.001 PMID:28177286

Are Diet Preferences Associated to Skulls Shape Diversification in Xenodontine Snakes?

PubMed Central

Klaczko, Julia; Sherratt, Emma; Setz, Eleonore Z. F.

2016-01-01

Snakes are a highly successful group of vertebrates, within great diversity in habitat, diet, and morphology. The unique adaptations for the snake skull for ingesting large prey in more primitive macrostomatan snakes have been well documented. However, subsequent diversification in snake cranial shape in relation to dietary specializations has rarely been studied (e.g. piscivory in natricine snakes). Here we examine a large clade of snakes with a broad spectrum of diet preferences to test if diet preferences are correlated to shape variation in snake skulls. Specifically, we studied the Xenodontinae snakes, a speciose clade of South American snakes, which show a broad range of diets including invertebrates, amphibians, snakes, lizards, and small mammals. We characterized the skull morphology of 19 species of xenodontine snakes using geometric morphometric techniques, and used phylogenetic comparative methods to test the association between diet and skull morphology. Using phylogenetic partial least squares analysis (PPLS) we show that skull morphology is highly associated with diet preferences in xenodontine snakes. PMID:26886549

Etude experimentale des excitations topologiques de l'effet Hall quantique a nu = 1 dans les heterostructures semiconductrices a double puits quantique

NASA Astrophysics Data System (ADS)

Charlebois, Serge

De nombreux travaux theoriques et experimentaux ont ete publies sur les excitations topologiques de gaz electroniques bidimensionnels (GE2D), appellees skyrmions, dans le regime de l'effet Hall quantique a remplissage unitaire. On attend des excitations semblables appellees bimerons dans les systemes formes de deux GE2D couples. Contrairement au cas des GE2D simples, aucune experience n'a, a notre connaissance, presente la mesure d'une propriete specifique aux bimerons. Nous presentons dans cette these des travaux experimentaux ayant pour objectif l'etude d'excitations topologiques dans les heterostructures a double puits quantique. Une manifestation attendue (les bimerons est la presence d'une anisotropie dans la conductivite a travers une constriction. Nous avons concu un dispositif original a point de contact a trois grilles non-coplanaires. Ce dispositif a trois grilles a la particularite de permettre la creation d'une constriction etroite dans le double GE2D tout en permettant l'equilibrage de la densite electronique entre les deux puits dans l'etroit canal de conduction. Nous avons fabrique ce dispositif de taille submicronique par electrolithographie sur des heterostructures a double puits. Les dispositifs ainsi fabriques ont ete etudies a basse temperature (0.3K) et ont montre un fonctionnement conforme aux attentes. Les travaux n'ont pas permis de mettre en evidence une anisotropie de transport revelatrice de l'existence de bimerons. Cette these est a notre connaissance la premiere etude experimentale visant la realisation de l'experience d'anisotropie de transport et est ainsi une contribution significative a l'avancement des connaissances dans ce domaine. Les travaux theoriques que nous presentons ont permis de montrer l'effet des excitations topologiques sur la capacite grille-GE2D du systeme. Ces travaux ouvrent la voie de la detection des bimerons par l'intermediaire de la mesure de la capacite grille-GE2D ou encore de la susceptibilite electrique du GE2D. Poursuivant cet objectif, nous avons concu, realise et teste un dispositif de mesure in situ de la capacite grille-GE2D d'une heterostructure. Nous avons egalement suggere d'autres methodes experimentales pour la mise en evidence des bimerons par le couplage de la texture de pseudospin a la capacite du GE2D.

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

Boppana, Venkata Bharat Ram; Hould, Nathan D.; Lobo, Raul F., E-mail: lobo@udel.ed

We report the first instance of a hydrothermal synthesis of zinc germanate (Zn{sub 2}GeO{sub 4}) nano-materials having a variety of morphologies and photochemical properties in surfactant, template and catalyst-free conditions. A systematic variation of synthesis conditions and detailed characterization using X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, Raman spectroscopy, electron microscopy, X-ray photoelectron spectroscopy and small angle X-ray scattering led to a better understanding of the growth of these particles from solution. At 140 {sup o}C, the zinc germanate particle morphology changes with pH from flower-shaped at pH 6.0, to poly-disperse nano-rods at pH 10 when the Zn to Ge ratiomore » in the synthesis solution is 2. When the Zn to Ge ratio is reduced to 1.25, mono-disperse nano-rods could be prepared at pH 7.5. Nanorod formation is also independent of the addition of cetyltrimethylammonium bromide (CTAB), in contrast to previous reports. Photocatalytic tests show that Zn{sub 2}GeO{sub 4} nano-rods (by weight) and flower shaped (by surface area) are the most active for methylene blue dye degradation among the synthesized zinc germanate materials. -- Graphical abstract: Zinc germanate materials were synthesized possessing unique morphologies dependent on the hydrothermal synthesis conditions in the absence of surfactant, catalyst or template. These novel materials are characterized and evaluated for their photocatalytic activities. Display Omitted highlights: > Zinc germanate synthesized hydrothermally (surfactant free) with unique morphologies. > Flower-shaped, nano-rods, globular particles obtained dependent on synthesis pH. > At 140 {sup o}C, they possess the rhombohedral crystal irrespective of synthesis conditions. > They are photocatalytically active for the degradation of methylene blue. > Potential applications could be photocatalytic water splitting and CO{sub 2} reduction.« less

Disease surveillance of Atlantic herring: molecular characterization of hepatic coccidiosis and a morphological report of a novel intestinal coccidian

USGS Publications Warehouse

Friend, Sarah E; Lovey, J; Hershberger, Paul

2016-01-01

Surveillance for pathogens of Atlantic herring, including viral hemorrhagic septicemia virus (VHSV),Ichthyophonus hoferi, and hepatic and intestinal coccidians, was conducted from 2012 to 2016 in the NW Atlantic Ocean, New Jersey, USA. Neither VHSV nor I. hoferi was detected in any sample. Goussia clupearum was found in the livers of 40 to 78% of adult herring in varying parasite loads; however, associated pathological changes were negligible. Phylogenetic analysis based on small subunit 18S rRNA gene sequences placed G. clupearum most closely with other extraintestinal liver coccidia from the genus Calyptospora, though the G. clupearum isolates had a unique nucleotide insertion between 604 and 729 bp that did not occur in any other coccidian species. G. clupearum oocysts from Atlantic and Pacific herring were morphologically similar, though differences occurred in oocyst dimensions. Comparison of G. clupearum genetic sequences from Atlantic and Pacific herring revealed 4 nucleotide substitutions and 2 gaps in a 1749 bp region, indicating some divergence in the geographically separate populations. Pacific G. clupearum oocysts were not directly infective, suggesting that a heteroxenous life cycle is likely. Intestinal coccidiosis was described for the first time from juvenile and adult Atlantic herring. A novel intestinal coccidian species was detected based on morphological characteristics of exogenously sporulated oocysts. A unique feature in these oocysts was the presence of 3 long (15.1 ± 5.1 µm, mean ±SD) spiny projections on both ends of the oocyst. The novel morphology of this coccidian led us to tentatively name this parasite G. echinata n. sp.

Zoanthid diversity (Anthozoa: Hexacorallia) in the Galapagos Islands: a molecular examination

NASA Astrophysics Data System (ADS)

Reimer, J. D.; Sinniger, F.; Hickman, C. P.

2008-09-01

Although the Galapagos are famous for their unique biodiversity, many groups of marine invertebrates from this isolated archipelago remain understudied or not investigated. One such group is the zoanthids (Order Zoantharia, =Zoanthidea, =Zoanthiniaria), anthozoans (Cnidaria) found in marine ecosystems worldwide. Zoanthid taxonomy has been in a state of disorganization and neglect due in large part to the morphological plasticity within species and questions about the accuracy of traditionally used morphological and ecological characteristics. However, recent studies utilizing molecular methodology combined with morphology have proven to be very useful in understanding zoanthid diversity. The results of a survey of zoanthids from the Galapagos and the east Pacific are reported in this study. Shallow water (<35 m) zoanthid specimens were identified using the molecular markers mitochondrial 16S ribosomal DNA (mt 16S rDNA), cytochrome oxidase subunit I (COI) gene, and the internal transcribed spacer of ribosomal DNA (ITS-rDNA). From the collected specimens seven putative zoanthid species-level clades from three known genera ( Zoanthus, Palythoa, Parazoanthus) were identified at the molecular level. These identifications were further supported by morphological and ecological data. While almost all specimens belonged to known zoanthid genera, based on unique molecular and ecological data one group of specimens (designated unknown zoanthid sp. “03-103”) is potentially a novel undescribed genus. Additionally, the remaining three azooxanthellate Parazoanthus clades may also be undescribed new species, but due to the overall lack of zoanthid research and descriptions from neighboring areas (East Pacific, west coast of South America) further research is needed to clearly ascertain this. Additionally, notes on the four observed nominal azooxanthellate zoanthid species and a key to all eight nominal (seven from known genera, one from a potentially new genus) shallow water zoanthid species found thus far in the Galapagos Islands are provided.

A new genus of miniaturized and pug-nosed gecko from South America (Sphaerodactylidae: Gekkota)

PubMed Central

Gamble, Tony; Daza, Juan D; Colli, Guarino R; Vitt, Laurie J; Bauer, Aaron M

2011-01-01

Sphaerodactyl geckos comprise five genera distributed across Central and South America and the Caribbean. We estimated phylogenetic relationships among sphaerodactyl genera using both separate and combined analyses of seven nuclear genes. Relationships among genera were incongruent at different loci and phylogenies were characterized by short, in some cases zero length, internal branches and poor phylogenetic support at most nodes. We recovered a polyphyletic Coleodactylus, with Coleodactylus amazonicus being deeply divergent from the remaining Coleodactylus species sampled. The C. amazonicus lineage possessed unique codon deletions in the genes PTPN12 and RBMX while the remaining Coleodactylus species had unique codon deletions in RAG1. Topology tests could not reject a monophyletic Coleodactylus, but we show that short internal branch lengths decreased the accuracy of topology tests because there were not enough data along short branches to support one phylogenetic hypothesis over another. Morphological data corroborated results of the molecular phylogeny, with Coleodactylus exhibiting substantial morphological heterogeneity. We identified a suite of unique craniofacial features that differentiate C. amazonicus not only from other Coleodactylus species, but also from all other geckos. We describe this novel sphaerodactyl lineage as a new genus, Chatogekko gen. nov. We present a detailed osteology of Chatogekko, characterizing osteological correlates of miniaturization that provide a framework for future studies in sphaerodactyl systematics and biology. PMID:22125341

The sea cucumber genome provides insights into morphological evolution and visceral regeneration

PubMed Central

Dai, Hui; Hamel, Jean-François; Liu, Chengzhang; Yu, Yang; Liu, Shilin; Lin, Wenchao; Guo, Kaimin; Jin, Songjun; Xu, Peng; Storey, Kenneth B.; Huan, Pin; Zhang, Tao; Zhou, Yi; Zhang, Jiquan; Lin, Chenggang; Li, Xiaoni; Xing, Lili; Huo, Da; Sun, Mingzhe; Wang, Lei; Mercier, Annie; Li, Fuhua; Yang, Hongsheng

2017-01-01

Apart from sharing common ancestry with chordates, sea cucumbers exhibit a unique morphology and exceptional regenerative capacity. Here we present the complete genome sequence of an economically important sea cucumber, A. japonicus, generated using Illumina and PacBio platforms, to achieve an assembly of approximately 805 Mb (contig N50 of 190 Kb and scaffold N50 of 486 Kb), with 30,350 protein-coding genes and high continuity. We used this resource to explore key genetic mechanisms behind the unique biological characters of sea cucumbers. Phylogenetic and comparative genomic analyses revealed the presence of marker genes associated with notochord and gill slits, suggesting that these chordate features were present in ancestral echinoderms. The unique shape and weak mineralization of the sea cucumber adult body were also preliminarily explained by the contraction of biomineralization genes. Genome, transcriptome, and proteome analyses of organ regrowth after induced evisceration provided insight into the molecular underpinnings of visceral regeneration, including a specific tandem-duplicated prostatic secretory protein of 94 amino acids (PSP94)-like gene family and a significantly expanded fibrinogen-related protein (FREP) gene family. This high-quality genome resource will provide a useful framework for future research into biological processes and evolution in deuterostomes, including remarkable regenerative abilities that could have medical applications. Moreover, the multiomics data will be of prime value for commercial sea cucumber breeding programs. PMID:29023486

The sea cucumber genome provides insights into morphological evolution and visceral regeneration.

PubMed

Zhang, Xiaojun; Sun, Lina; Yuan, Jianbo; Sun, Yamin; Gao, Yi; Zhang, Libin; Li, Shihao; Dai, Hui; Hamel, Jean-François; Liu, Chengzhang; Yu, Yang; Liu, Shilin; Lin, Wenchao; Guo, Kaimin; Jin, Songjun; Xu, Peng; Storey, Kenneth B; Huan, Pin; Zhang, Tao; Zhou, Yi; Zhang, Jiquan; Lin, Chenggang; Li, Xiaoni; Xing, Lili; Huo, Da; Sun, Mingzhe; Wang, Lei; Mercier, Annie; Li, Fuhua; Yang, Hongsheng; Xiang, Jianhai

2017-10-01

Apart from sharing common ancestry with chordates, sea cucumbers exhibit a unique morphology and exceptional regenerative capacity. Here we present the complete genome sequence of an economically important sea cucumber, A. japonicus, generated using Illumina and PacBio platforms, to achieve an assembly of approximately 805 Mb (contig N50 of 190 Kb and scaffold N50 of 486 Kb), with 30,350 protein-coding genes and high continuity. We used this resource to explore key genetic mechanisms behind the unique biological characters of sea cucumbers. Phylogenetic and comparative genomic analyses revealed the presence of marker genes associated with notochord and gill slits, suggesting that these chordate features were present in ancestral echinoderms. The unique shape and weak mineralization of the sea cucumber adult body were also preliminarily explained by the contraction of biomineralization genes. Genome, transcriptome, and proteome analyses of organ regrowth after induced evisceration provided insight into the molecular underpinnings of visceral regeneration, including a specific tandem-duplicated prostatic secretory protein of 94 amino acids (PSP94)-like gene family and a significantly expanded fibrinogen-related protein (FREP) gene family. This high-quality genome resource will provide a useful framework for future research into biological processes and evolution in deuterostomes, including remarkable regenerative abilities that could have medical applications. Moreover, the multiomics data will be of prime value for commercial sea cucumber breeding programs.

Architecture and morphology of coral reef sequences. Modeling and observations from uplifting islands of SE Sulawesi, Indonesia

NASA Astrophysics Data System (ADS)

Pastier, Anne-Morwenn; Husson, Laurent; Bezos, Antoine; Pedoja, Kevin; Elliot, Mary; Hafidz, Abdul; Imran, Muhammad; Lacroix, Pascal; Robert, Xavier

2016-04-01

During the Late Neogene, sea level oscillations have profoundly shaped the morphology of the coastlines of intertropical zones, wherein relative sea level simultaneously controlled reef expansion and erosion of earlier reef bodies. In uplifted domains like SE Sulawesi, the sequences of fossil reefs display a variety of fossil morphologies. Similarly, the morphologies of the modern reefs are highly variable, including cliff notches, narrow fringing reefs, wide flat terraces, and barriers reefs. In this region, where uplift rates vary rapidly laterally, the entire set of morphologies is displayed within short distances. We developed a numerical model that predicts the architecture of fossil reefs sequences and apply it to observations from SE Sulawesi, accounting -amongst other parameters- for reef growth, coastal erosion, and uplift rates. The observations that we use to calibrate our models are mostly the morphology of both the onshore (dGPS and high-resolution Pleiades DEM) and offshore (sonar) coast, as well as U-Th radiometrically dated coral samples. Our method allows unravelling the spatial and temporal evolution of large domains on map view. Our analysis indicates that the architecture and morphology of uplifting coastlines is almost systematically polyphased (as attested by samples of different ages within a unique terrace), which assigns a primordial role to erosion, comparable to reef growth. Our models also reproduce the variety of modern morphologies, which are chiefly dictated by the uplift rates of the pre-existing morphology of the substratum, itself responding to the joint effects of reef building and subsequent erosion. In turn, we find that fossil and modern morphologies can be returned to uplift rates rather precisely, as the parametric window of each specific morphology is often narrow.

A new species of karst-adapted Cnemaspis Strauch, 1887 (Squamata: Gekkonidae) from a threatened karst region in Pahang, Peninsular Malaysia.

PubMed

Grismer, L Lee; Wood, Perry L; Mohamed, Maketab; Chan, Kin Onn; Heinz, Heather M; Sumarli, Alex S-I; Chan, Jacob A; Loredo, Ariel I

2013-12-12

A new species of karst-adapted gekkonid lizard of the genus Cnemaspis Strauch is described from Gua Gunting and Gua Goyang in a karst region of Merapoh, Pahang, Peninsular Malaysia whose unique limestone formations are in immediate danger of being quarried. The new species differs from all other species of Cnemaspis based on its unique suite of morphological and color pattern characters. Its discovery underscores the unique biodiversity endemic to karst regions and adds to a growing list of karst-adapted reptiles from Peninsular Malaysia. We posit that new karst-adapted species endemic to limestone forests will continue to be discovered and these regions will harbor a significant percentage of Peninsular Malaysia's biodiversity and thusly should be conserved rather than quarried.

Organogenesis in deep time: A problem in genomics, development, and paleontology.

PubMed

Pieretti, Joyce; Gehrke, Andrew R; Schneider, Igor; Adachi, Noritaka; Nakamura, Tetsuya; Shubin, Neil H

2015-04-21

The fossil record is a unique repository of information on major morphological transitions. Increasingly, developmental, embryological, and functional genomic approaches have also conspired to reveal evolutionary trajectory of phenotypic shifts. Here, we use the vertebrate appendage to demonstrate how these disciplines can mutually reinforce each other to facilitate the generation and testing of hypotheses of morphological evolution. We discuss classical theories on the origins of paired fins, recent data on regulatory modulations of fish fins and tetrapod limbs, and case studies exploring the mechanisms of digit loss in tetrapods. We envision an era of research in which the deep history of morphological evolution can be revealed by integrating fossils of transitional forms with direct experimentation in the laboratory via genome manipulation, thereby shedding light on the relationship between genes, developmental processes, and the evolving phenotype.

Mineral Biomarkers in Martian Meteorite Allan Hills 84001?

NASA Technical Reports Server (NTRS)

Thomas-Keprta, K. L.; Bazylinski, D. A.; Wentworth, S. J.; McKay, D. S.; Golden, D. C.; Gibson, E. K., Jr.; Romanek, C. S.

1998-01-01

The occurrence of fine-grained magnetite in the Fe-rich rims surrounding carbonate globules in the martian meteorite ALH84001, originally described in , have been proposed as fossil remains of primitive martian organisms. Here we report observations on size and shape distributions of magnetites from ALH84001 and compare them to biogenic and inorganic magnetite crystals of terrestrial origin. While some magnetite morphology is not unequivocally diagnostic for its biogenicity, such as cubodial forms of magnetite, which are common in inorganically formed magnetites, other morphologies of magnetite (parallel-epiped or elongated prismatic and arrowhead forms) are more likely signatures of biogenic activity. Some ALH 84001 magnetite particles described below have unique morphology and length-to-width ratios that are indistinguishable from a variety of terrestrial biogenic magnetite and distinct from all known inorganic forms of magnetite.

What controls channel form in steep mountain streams?

NASA Astrophysics Data System (ADS)

Palucis, M. C.; Lamb, M. P.

2017-07-01

Steep mountain streams have channel morphologies that transition from alternate bar to step-pool to cascade with increasing bed slope, which affect stream habitat, flow resistance, and sediment transport. Experimental and theoretical studies suggest that alternate bars form under large channel width-to-depth ratios, step-pools form in near supercritical flow or when channel width is narrow compared to bed grain size, and cascade morphology is related to debris flows. However, the connection between these process variables and bed slope—the apparent dominant variable for natural stream types—is unclear. Combining field data and theory, we find that certain bed slopes have unique channel morphologies because the process variables covary systematically with bed slope. Multiple stable states are predicted for other ranges in bed slope, suggesting that a competition of underlying processes leads to the emergence of the most stable channel form.

Biosynthesis of spherical and highly stable gold nanoparticles using Ferulago Angulata aqueous extract: dual role of extract

NASA Astrophysics Data System (ADS)

Alizadeh, A.; Parsafar, S.; Khodaei, M. M.

2017-03-01

A biocompatible method for synthesizing of highly disperses gold nanoparticles using Ferulago Angulata leaf extract has been developed. It has been shown that leaf extract acts as reducing and coating agent. Various spectroscopic and electron microscopic techniques were employed for the structural characterization of the prepared nanoparticles. The biosynthesized particles were identified as elemental gold with spherical morphology, narrow size distribution (ranged 9.2-17.5 nm) with high stability. Also, the effect of initial ratio of precursors, temperature and time of reaction on the size and morphology of the nanoparticles was studied in more detail. It was observed that varying these parameters provides an accessible remote control on the size and morphology of nanoparticles. The uniqueness of this procedure lies in its cleanliness using no extra surfactant, reducing agent or any capping agent.

Report of the Working Group on Aerodynamics of Aircraft Afterbody.

DTIC Science & Technology

1986-06-01

14 I 21 2.1.71 Addy A.L. Experimeftal-Theoretical Correlation of Supersonic Jet-on Base Pressure for Cylindrical Afterbodies. J. Aircraft, Vol. 7, No...An Improved Experimental-Theoretical Base Pressure Cor- Addy A.L. relation for Conical and Cylindrical Afterbodies with Agrell J. Centered Propulsive...2.1.92 Carri~re P. Effet d’une Injection de Fluide dans l’Eau-Morte sur les Conditions de Recollement d’un Ecoulement Plan Supersonique. Comptes

Wind Tunnel Wall Corrections (la Correction des effets de paroi en soufflerie)

DTIC Science & Technology

1998-10-01

round holes drilled either normal to the wall surface or at a fixed angle to the normal. Variable porosity features have been implemented in several...walls (holes drilled at 60 deg from the normal), including variable porosity configurations and the effects of screens and splitter plates for edge-tone...Figure 5.68 Schematic of slender wing and the indicated gauge func- tions in anticipation of matching. As detailed in Malmuth and Cole [122], the problems

Quel effet de l’euro sur le commerce europeen des produits forestiers? Académie d’Agriculture de France, Notes Académiques

Treesearch

Joseph Buongiorno

2015-01-01

The objective of this study was to determine the effect of the monetary union on the trade of forest products between euro-using countries. A differential gravity model of bilateral trade flows was developed and estimated with data for the bilateral trade between 12 euro countries from 1988 to 2013, for commodity groups HS44 (wood and articles of wood), HS47 (pulp of...

Africa Civic Action Planning and Implementation Guide

DTIC Science & Technology

1988-03-17

transfert du titre de propriet4 ou. que les d~fectuosit~s provenant de la conception sont... transfert du * .~.titre prendra effet normalement. au point de chargement chez le * fabricant; et pour ].es articles de de’fense fournis sur les stocks...dition avant l~e transfert . du Ititre de proprie’t4. Si l~e "lieu de livraison" d~sign4 est autre que le point initial d’expe’d’tion, l~e

[cAMP mediates the morphological change of cultured olfactory ensheathing cells induced by serum].

PubMed

Wang, Ying; Huang, Zhi-Hui

2011-02-25

Olfactory ensheathing cells (OECs) are a unique type of glia with common properties of astrocyte and Schwann cells. Cultured OECs have two morphological phenotypes, astrocyte-like OECs and Schwann cell-like OECs. Reversible changes have been found between these two morphological phenotypes. However, the molecular mechanism underlying the regulation of these reversible changes is still unknown. The aim of this paper is to establish a method for the morphology plasticity of cultured OECs, and investigate the underlying mechanism. Using the primary culture of OECs and immunocytochemistry, the morphology of OECs was observed under serum, serum free media or dB-cAMP drug treatment. Statistical analysis was performed to test differences among the percentages of OEC subtypes under these conditions. The results showed that under serum free media, (95.2±3.7)% of OECs showed Schwann cell-like morphology, and (4.8±3.7)% of OECs showed astrocyte-like morphology; however, under 10% serum media, (42.5±10.4)% of OECs exhibited Schwann cell-like morphology, and (57.5±10.4)% of OECs exhibited astrocyte-like morphology. When media was changed back to serum free media for 24 h, (94.8±5.0)% of OECs showed Schwann cell-like morphology, and (5.2±5.0)% of OECs showed astrocyte-like morphology. Furthermore, culture condition with or without serum did not affect the expression of OEC cell marker, p-75 and S-100. Finally, dB-cAMP, an analog of cAMP, through inhibiting the formation of F-actin stress fibers and focal adhesion, induced the morphology switch from astrocyte-like to Schwann cell-like morphology under serum condition, promoted the branches and the growth of processes. These results suggest that serum induces the morphology plasticity of cultured OECs, which is mediated by cytoplasmic cAMP level through regulating the formation of F-actin stress fibers and focal adhesion.

Pharmacogénétique: qu'en est-il au Maroc?

PubMed Central

Idrissi, Meryem Janati; Ouldim, Karim; Amarti, Afaf; El Hassouni, Mohamed; Khabbal, Youssef

2013-01-01

La pharmacogénétique est l’étude de l'influence des variations génétiques interindividuelles sur la réponse aux médicaments, avec le but d'améliorer la prise en charge des patients en visant une médecine personnalisée. Au fait le génome de deux personnes ne diffère que par 0.1% des 3.2 milliards de paires de bases, ce qui implique les effets indésirables des médicaments, qui ont un très important impact sur le plan clinique que sur le plan économique. Or cette dernière décennie ces effets indésirables ont pu être évités grâce aux tests pharmacogénétiques. Au Maroc, la recherche en pharmacogénétique commence à susciter l'intérêt des chercheurs avec quelques études. Une toute première étude en 1986, sur l'acétylation de l'isoniazide chez la population marocaine, suivie par deux autres en 2011 se focalisant sur le métabolisme du tacrolimus et des anti-vitamines K. Ainsi l'espoir maintenant est d'identifier les majoritaires polymorphismes génétiques affectant les patients marocains, afin de leur fournir une prise en charge adaptée. PMID:23785548

Kerr effect in the isotropic phase of a side-chain polymeric liquid crystal

NASA Astrophysics Data System (ADS)

Reys, V.; Dormoy, Y.; Collin, D.; Keller, P.; Martinoty, P.

1992-02-01

The birefringence induced by a pulsed electrical field was used to study the pretransitional effects associated with the isotropic phase of a side-chain polysiloxane. The results obtained show that these effects are characterised by a conventional value of the static exponent and an abnormal value of the dynamic exponent, which shows that the dynamic theory of low molecular weight liquid crystals does not apply. The results also reveal competition between the dipolar moments induced by the electrical field and the permanent moments of the mesogenic molecules. La biréfringence induite par un champ électrique impulsionnel a été utilisée pour étudier les effets prétransitionnels associés à la phase isotrope d'un polysiloxane à chaînes latérales. Les résultats obtenus montrent que ces effets sont caractérisés par une valeur classique de l'exposant statique et une valeur anormale de l'exposant dynamique. Ce dernier résultat montre que la théorie dynamique des cristaux liquides de bas poids moléculaire n'est pas applicable au cas présent. Les expériences mettent également en évidence une compétition entre les moments dipolaires induits par le champ électrique et les moments permanents des molécules mésogènes.

Excitations Élémentaires au Voisinage de la Surface de Séparation d'un Métal Normal et d'un Métal Supraconducteur

NASA Astrophysics Data System (ADS)

Saint-James, Par D.

On étudie le spectre d'excitation pour une couche de métal normal déposée sur un supraconducteur. On montre que si l'interaction attractive électron-électron est négligeable dans le métal normal, il n'y a pas de gap d'énergie dans le spectre d'excitation, même si l'épaisseur de la couche normale est petite. Une étude analogue, conduisant à une conclusion similaire, est menée pour deux supraconducteurs accolés et pour des sphères de métal normal baignant dans un supraconducteur. L'effet prévu pourrait expliquer quelques résultats particuliers observés dans des mesures d'effet tunnel dans des supraconducteurs durs. The excitation spectrum of a layer of normal metal (N) deposited on a superconducting substrate (S) is discussed. It is shown that if the electron-electron attractive interaction is negligibly small in (N) there is no energy gap in the excitation spectrum even if the thickness of the layer (N) is small. A similar study, with equivalent conclusions, has been carried out for two superconductors and for normal metal spheres embedded in a superconductor. The effect may possibly explain some peculiar results of tunnelling experiments on hard superconductors.

Extensive morphological divergence and rapid evolution of the larval neuromuscular junction in Drosophila.

PubMed

Campbell, Megan; Ganetzky, Barry

2012-03-13

Although the complexity and circuitry of nervous systems undergo evolutionary change, we lack understanding of the general principles and specific mechanisms through which it occurs. The Drosophila larval neuromuscular junction (NMJ), which has been widely used for studies of synaptic development and function, is also an excellent system for studies of synaptic evolution because the genus spans >40 Myr of evolution and the same identified synapse can be examined across the entire phylogeny. We have now characterized morphology of the NMJ on muscle 4 (NMJ4) in >20 species of Drosophila. Although there is little variation within a species, NMJ morphology and complexity vary extensively between species. We find no significant correlation between NMJ phenotypes and phylogeny for the species examined, suggesting that drift alone cannot explain the phenotypic variation and that selection likely plays an important role. However, the nature of the selective pressure is still unclear because basic parameters of synaptic function remain uniform. Whatever the mechanism, NMJ morphology is evolving rapidly in comparison with other morphological features because NMJ phenotypes differ even between several sibling species pairs. The discovery of this unexpectedly extensive divergence in NMJ morphology among Drosophila species provides unique opportunities to investigate mechanisms that regulate synaptic growth; the interrelationships between synaptic morphology, neural function, and behavior; and the evolution of nervous systems and behavior in natural populations.

Genera of euophryine jumping spiders (Araneae: Salticidae), with a combined molecular-morphological phylogeny.

PubMed

Zhang, Junxia; Maddison, Wayne P

2015-03-27

Morphological traits of euophryine jumping spiders were studied to clarify generic limits in the Euophryinae and to permit phylogenetic classification of genera lacking molecular data. One hundred and eight genera are recognized within the subfamily. Euophryine generic groups and the delimitation of some genera are reviewed in detail. In order to explore the effect of adding formal morphological data to previous molecular phylogenetic studies, and to find morphological synapomorphies, eighty-two morphological characters were scored for 203 euophryine species and seven outgroup species. The morphological dataset does not perform as well as the molecular dataset (genes 28S, Actin 5C; 16S-ND1, COI) in resolving the phylogeny of Euophryinae, probably because of frequent convergence and reversal. The formal morphological data were mapped on the phylogeny in order to seek synapomorphies, in hopes of extending the phylogeny to include taxa for which molecular data are not available. Because of homoplasy, few globally-applicable morphological synapomorphies for euophryine clades were found. However, synapomorphies that are unique locally in subclades still help to delimit euophryine generic groups and genera. The following synonyms of euophryine genera are proposed: Maeotella with Anasaitis; Dinattus with Corythalia; Paradecta with Compsodecta; Cobanus, Chloridusa and Wallaba with Sidusa; Tariona with Mopiopia; Nebridia with Amphidraus; Asaphobelis and Siloca with Coryphasia; Ocnotelus with Semnolius; Palpelius with Pristobaeus; Junxattus with Laufeia; Donoessus with Colyttus; Nicylla, Pselcis and Thianitara with Thiania. The new genus Saphrys is erected for misplaced species from southern South America.

Morphology inherence from hollow MOFs to hollow carbon polyhedrons in preparing carbon-based electrocatalysts

DOE PAGES

Pei, Yuchen; Qi, Zhiyuan; Li, Xinle; ...

2017-02-21

Hollow carbon nanostructures are emerging as advanced electrocatalysts for the oxygen reduction reaction (ORR) due to the effective usage of active sites and the reduced dependence on expensive noble metals. Conventional preparation of these hollow structures is achieved through templates (e.g. SiO 2, CdS, and Ni 3C), which serve to retain the void interiors during carbonization, leading to an essential template-removal procedure using hazardous chemical etchants. Herein, we demonstrate the direct carbonization of unique hollow zeolitic imidazolate frameworks (ZIFs) for the synthesis of hollow carbon polyhedrons (HCPs) with well-defined morphologies. The hollow ZIF particles behave bi-functionally as a carbon sourcemore » and a morphology directing agent. This method evidences the strong morphology inherence from the hollow ZIFs during the carbonization, advancing the significant simplicity and environmental friendliness of this synthesis strategy. The as-prepared HCPs show a uniform polyhedral morphology and large void interiors, which enable their superior ORR activity. Iron can be doped into the HCPs (Fe/HCPs), providing the Fe/HCPs with enhanced ORR properties ( E 1/2 = 0.850 V) in comparison with those of HCPs. As a result, we highlight the efficient structural engineering to transform ZIFs into advanced carbon nanostructures accomplishing morphological control and high electrocatalytic activity.« less

Morphology inherence from hollow MOFs to hollow carbon polyhedrons in preparing carbon-based electrocatalysts

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

Pei, Yuchen; Qi, Zhiyuan; Li, Xinle

Hollow carbon nanostructures are emerging as advanced electrocatalysts for the oxygen reduction reaction (ORR) due to the effective usage of active sites and the reduced dependence on expensive noble metals. Conventional preparation of these hollow structures is achieved through templates (e.g. SiO 2, CdS, and Ni 3C), which serve to retain the void interiors during carbonization, leading to an essential template-removal procedure using hazardous chemical etchants. Herein, we demonstrate the direct carbonization of unique hollow zeolitic imidazolate frameworks (ZIFs) for the synthesis of hollow carbon polyhedrons (HCPs) with well-defined morphologies. The hollow ZIF particles behave bi-functionally as a carbon sourcemore » and a morphology directing agent. This method evidences the strong morphology inherence from the hollow ZIFs during the carbonization, advancing the significant simplicity and environmental friendliness of this synthesis strategy. The as-prepared HCPs show a uniform polyhedral morphology and large void interiors, which enable their superior ORR activity. Iron can be doped into the HCPs (Fe/HCPs), providing the Fe/HCPs with enhanced ORR properties ( E 1/2 = 0.850 V) in comparison with those of HCPs. As a result, we highlight the efficient structural engineering to transform ZIFs into advanced carbon nanostructures accomplishing morphological control and high electrocatalytic activity.« less

Elevated rates of morphological and functional diversification in reef-dwelling haemulid fishes.

PubMed

Price, Samantha A; Tavera, Jose J; Near, Thomas J; Wainwright, Peter C

2013-02-01

The relationship between habitat complexity and species richness is well established but comparatively little is known about the evolution of morphological diversity in complex habitats. Reefs are structurally complex, highly productive shallow-water marine ecosystems found in tropical (coral reefs) and temperate zones (rocky reefs) that harbor exceptional levels of biodiversity. We investigated whether reef habitats promote the evolution of morphological diversity in the feeding and locomotion systems of grunts (Haemulidae), a group of predominantly nocturnal fishes that live on both temperate and tropical reefs. Using phylogenetic comparative methods and statistical analyses that take into account uncertainty in phylogeny and the evolutionary history of reef living, we demonstrate that rates of morphological evolution are faster in reef-dwelling haemulids. The magnitude of this effect depends on the type of trait; on average, traits involved in the functional systems for prey capture and processing evolve twice as fast on reefs as locomotor traits. This result, along with the observation that haemulids do not exploit unique feeding niches on reefs, suggests that fine-scale trophic niche partitioning and character displacement may be driving higher rates of morphological evolution. Whatever the cause, there is growing evidence that reef habitats stimulate morphological and functional diversification in teleost fishes. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Patterned functional carbon fibers from polyethylene.

PubMed

Hunt, Marcus A; Saito, Tomonori; Brown, Rebecca H; Kumbhar, Amar S; Naskar, Amit K

2012-05-08

Carbon fibers having unique morphologies, from hollow circular to gear-shaped, are produced from a novel melt-processable precursor and method. The resulting carbon fiber exhibits microstructural and topological properties that are dependent on processing conditions, rendering them highly amenable to myriad applications. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Apple (Malus H domestica Borkh.) responds to a simulated severe drought: genes common and unique to leaves and bark

USDA-ARS?s Scientific Manuscript database

Dehydration is feature of many abiotic stresses, but is more often an agricultural threat on its own. Plants have evolved numerous mechanisms for coping with dehydration, including morphological, biochemical, and molecular genetic responses. These mechanisms are complex and involve various combina...

The protolobar structure of the human kidney: Its biologic and clinical significance

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

Inke, G.

This book depicts the uniqueness of each kidney as a result of the interaction of the process of nephronogenesis with the random variability of vascular channels within the bounds of a limited space. The fields of anatomy, developmental biology, comparative morphology, embryology, nephrology, pathology, physiology, radiology, and urologic surgery are treated.

Mapping Cortical Morphology in Youth with Velocardiofacial (22q11.2 Deletion) Syndrome

ERIC Educational Resources Information Center

Kates, Wendy R.; Bansal, Ravi; Fremont, Wanda; Antshel, Kevin M.; Hao, Xuejun; Higgins, Anne Marie; Liu, Jun; Shprintzen, Robert J.; Peterson, Bradley S.

2011-01-01

Objective: Velocardiofacial syndrome (VCFS; 22q11.2 deletion syndrome) represents one of the highest known risk factors for schizophrenia. Insofar as up to 30% of individuals with this genetic disorder develop schizophrenia, VCFS constitutes a unique, etiologically homogeneous model for understanding the pathogenesis of schizophrenia. Method:…

Genetic evidence of hybridization between Onothera wolfii (Wolf's evening primrose) and O. glaziovana, a garden escape

Treesearch

Jennifer DeWoody; Leonel Arguello; David Imper; Robert D. Westfall; Valerie D. Hipkins

2008-01-01

Isozyme analysis of the rare Oenothera wolfii (Wolf's evening primrose) and the garden escape, O. glazioviana, indicates that hybridization between these species may be more widespread than morphological evidence indicates. Although both species contained low amounts of genetic variation, unique alleles were identified in...

Single-crystalline dendritic bimetallic and multimetallic nanocubes.

PubMed

Kuang, Yun; Zhang, Ying; Cai, Zhao; Feng, Guang; Jiang, Yingying; Jin, Chuanhong; Luo, Jun; Sun, Xiaoming

2015-12-01

Developing facial synthetic routes for fabrication of multimetallic nanocatalysts with open porous morphology, tunable composition and tailored crystalline structure is a big challenge for fabrication of low-cost electrocatalysts. Here we report on the synthesis of single-crystalline dendritic bimetallic and multimetallic nanocubes via a solvothermal co-reduction method. These cubes show highly porous, complex 3D inner connections but single-crystalline structure. Tuning the reduction kinetics of metal precursors and introducing galvanic reaction at the active sites during growth were believed to be the keys for the formation of such unique nanostructure. Electro-catalytic oxygen reduction (ORR) and methanol oxidation (MOR) on these catalysts showed dramatic enhancements for both cathodic and anodic electrocatalysis in fuel cells, which were attributed to their unique morphology and crystalline structure, as well as synergetic effect of the multi-metallic components. This work uncovers the formation mechanism of such complex single-crystalline dendritic multimetallic nanocrystals and offers a promising synthetic strategy for geometric and crystalline control of multimetallic nanocrystals with tailored physical and chemical properties, which will benefit the development of clean energy.

New hairworm (Nematomorpha, Gordiida) species described from the Arizona Madrean Sky Islands.

PubMed

Swanteson-Franz, Rachel J; Marquez, Destinie A; Goldstein, Craig I; Andreas Schmidt-Rhaesa; Bolek, Matthew G; Hanelt, Ben

2018-01-01

Gordiids, or freshwater hairworms, are members of the phylum Nematomorpha that use terrestrial definitive hosts (arthropods) and live as adults in rivers, lakes, or streams. The genus Paragordius consists of 18 species, one of which was described from the Nearctic in 1851. More than 150 years later, we are describing a second Paragordius species from a unique habitat within the Nearctic; the Madrean Sky Island complex. The Madrean Sky Islands are a series of isolated high mountains in northern Mexico and the southwestern United States (Arizona and New Mexico), and are well known for their high diversity and endemicity. The new species is described based on both molecular data (COI barcoding) and morphological characters of the eggs, larvae, cysts, and adults. Adult females have unique small oblong mounds present on the interior of the trifurcating lobes with randomly dispersed long hairs extending from the furrows between the mounds. Marked genetic differences support observed morphological differences. This species represents the second new hairworm to be described from the Madrean Sky Islands, and it may represent the first endemic hairworm from this biodiversity hotspot.

A Unique Finite Element Modeling of the Periodic Wave Transformation over Sloping and Barred Beaches by Beji and Nadaoka's Extended Boussinesq Equations

PubMed Central

Jabbari, Mohammad Hadi; Sayehbani, Mesbah; Reisinezhad, Arsham

2013-01-01

This paper presents a numerical model based on one-dimensional Beji and Nadaoka's Extended Boussinesq equations for simulation of periodic wave shoaling and its decomposition over morphological beaches. A unique Galerkin finite element and Adams-Bashforth-Moulton predictor-corrector methods are employed for spatial and temporal discretization, respectively. For direct application of linear finite element method in spatial discretization, an auxiliary variable is hereby introduced, and a particular numerical scheme is offered to rewrite the equations in lower-order form. Stability of the suggested numerical method is also analyzed. Subsequently, in order to display the ability of the presented model, four different test cases are considered. In these test cases, dispersive and nonlinearity effects of the periodic waves over sloping beaches and barred beaches, which are the common coastal profiles, are investigated. Outputs are compared with other existing numerical and experimental data. Finally, it is concluded that the current model can be further developed to model any morphological development of coastal profiles. PMID:23853534

A new look at lunar soil collected from the sea of tranquility during the Apollo 11 mission.

PubMed

Kiely, Carol; Greenberg, Gary; Kiely, Christopher J

2011-02-01

Complementary state-of-the-art optical, scanning electron, and X-ray microscopy techniques have been used to study the morphology of Apollo 11 lunar soil particles (10084-47). The combination of innovative lighting geometries with image processing of a through focal series of images has allowed us to obtain a unique collection of high-resolution light micrographs of these fascinating particles. Scanning electron microscopy (SEM) stereo-pair imaging has been exploited to illustrate some of the unique morphological properties of lunar regolith. In addition, for the first time, X-ray micrographs with submicron resolution have been taken of individual particles using X-ray ultramicroscopy (XuM). This SEM-based technique lends itself readily to the imaging of pores, cracks, and inclusions and allows the internal structure of an entire particle to be viewed. Rotational SEM and XuM movies have also been constructed from a series of images collected at sequential angles through 360°. These offer a new and insightful view of these complex particles providing size, shape, and spatial information on many of their internal features.

Sargassum-associated mobile fauna communities in the Caribbean, Gulf of Mexico, and Sargasso Sea

NASA Astrophysics Data System (ADS)

Martin, L.; Schell, J. M.; Goodwin, D.; Biggs, D.; Siuda, A. N.

2016-02-01

Sargassum natans and S. fluitans are entirely pelagic, offering a pseudo-benthic structural habitat for an associated community of mobile fauna. In turn, the mobile fauna community supports foraging seabirds, fish, and turtles. Recent satellite observations suggest Sargassum in the Sargasso Sea is seeded annually from the Gulf of Mexico. Furthermore, the Caribbean is in the midst of a Sargassum inundation that appears disconnected in origin from the Sargasso Sea and Gulf of Mexico. Sargassum and fauna were collected via dip net during spring and summer 2015 from the Gulf of Mexico, Sargasso Sea and Eastern Caribbean to study the impacts that region, aggregation pattern (isolated clump, windrow, mat), and Sargassum variety morphology have on mobile fauna community composition. Sargassum from all three regions shared five common (frequency >10%) species: flatworm spp., Portunus sayi, Litiopa melanostoma, Leander tenuicornis, and Latreutes fucorum). The Gulf presented the most unique species (9 unique / 16 total) followed by the Sargasso Sea (5 unique / 12 total) and the Caribbean (1 unique / 6 total). The majority of species unique to the Gulf of Mexico were juvenile fish while those in the Caribbean and Sargasso Sea were benthic-like species residing on the Sargassum itself. Differences in the morphological forms of Sargassum had a marked effect on fauna diversity and abundance. In all three regions, fewer individuals and species were found on the broad-leafed, less compact S. natans VIII than on the denser S. natans I and S. fluitans III. This study identifies the differences in macrofauna abundance and diversity between varieties of Sargassum and highlights the potential for dramatic community changes that could result from largescale Sargassum blooms and species shifts. Any shift in these keystone communities could result in negative cascading effects on seabirds, economically important fish populations, and juvenile turtles which use the seaweed as a nursery habitat.

A Giant Chelonioid Turtle from the Late Cretaceous of Morocco with a Suction Feeding Apparatus Unique among Tetrapods

PubMed Central

Bardet, Nathalie; Jalil, Nour-Eddine; de Lapparent de Broin, France; Germain, Damien; Lambert, Olivier; Amaghzaz, Mbarek

2013-01-01

Background Secondary adaptation to aquatic life occurred independently in several amniote lineages, including reptiles during the Mesozoic and mammals during the Cenozoic. These evolutionary shifts to aquatic environments imply major morphological modifications, especially of the feeding apparatus. Mesozoic (250–65 Myr) marine reptiles, such as ichthyosaurs, plesiosaurs, mosasaurid squamates, crocodiles, and turtles, exhibit a wide range of adaptations to aquatic feeding and a broad overlap of their tooth morphospaces with those of Cenozoic marine mammals. However, despite these multiple feeding behavior convergences, suction feeding, though being a common feeding strategy in aquatic vertebrates and in marine mammals in particular, has been extremely rarely reported for Mesozoic marine reptiles. Principal Findings A relative of fossil protostegid and dermochelyoid sea turtles, Ocepechelon bouyai gen. et sp. nov. is a new giant chelonioid from the Late Maastrichtian (67 Myr) of Morocco exhibiting remarkable adaptations to marine life (among others, very dorsally and posteriorly located nostrils). The 70-cm-long skull of Ocepechelon not only makes it one of the largest marine turtles ever described, but also deviates significantly from typical turtle cranial morphology. It shares unique convergences with both syngnathid fishes (unique long tubular bony snout ending in a rounded and anteriorly directed mouth) and beaked whales (large size and elongated edentulous jaws). This striking anatomy suggests extreme adaptation for suction feeding unmatched among known turtles. Conclusion/Significance The feeding apparatus of Ocepechelon, a bony pipette-like snout, is unique among tetrapods. This new taxon exemplifies the successful systematic and ecological diversification of chelonioid turtles during the Late Cretaceous. This new evidence for a unique trophic specialization in turtles, along with the abundant marine vertebrate faunas associated to Ocepechelon in the Late Maastrichtian phosphatic beds of Morocco, further supports the hypothesis that marine life was, at least locally, very diversified just prior to the Cretaceous/Palaeogene (K/Pg) biotic crisis. PMID:23874378

Corallite skeletal morphological variation in Hawaiian Porites lobata

NASA Astrophysics Data System (ADS)

Tisthammer, Kaho H.; Richmond, Robert H.

2018-06-01

Due to their high morphological plasticity and complex evolutionary history, the species boundaries of many reef-building corals are poorly understood. The skeletal structures of corals have traditionally been used for species identification, but these structures can be highly variable, and currently we lack knowledge regarding the extent of morphological variation within species. Porites species are notorious for their taxonomic difficulties, both morphologically and genetically, and currently there are several unresolved species complexes in the Pacific. Despite its ubiquitous presence and broad use in coral research, Porites lobata belongs to one such unresolved species complex. To understand the degree of intraspecific variation in skeletal morphology, 120 corallites from the Hawaiian P. lobata were examined. A subset of samples from two genetically differentiated populations from contrasting high- and low-stress environments in Maunalua Bay, Hawaii, were then quantitatively analyzed using multivariate morphometrics. Our observations revealed high intraspecific variation in corallite morphology, as well as significant morphological differences between the two populations of P. lobata. Additionally, significant correlation was found between the morphological and genetic distances calculated from approximately 18,000 loci generated from restriction site-associated DNA sequencing. The unique morphological characters observed from the genetically differentiated population under environmental stress suggest that these characters may have adaptive values, but how such traits relate to fitness and how much plasticity they can exhibit remain to be determined by future studies. Relatively simple morphometric analyses used in our study can be useful in clarifying the existing ambiguity in skeletal architecture, thus contributing to resolving species issues in corals.

Molecular characterization of organic electronic films.

PubMed

DeLongchamp, Dean M; Kline, R Joseph; Fischer, Daniel A; Richter, Lee J; Toney, Michael F

2011-01-18

Organic electronics have emerged as a viable competitor to amorphous silicon for the active layer in low-cost electronics. The critical performance of organic electronic materials is closely related to their morphology and molecular packing. Unlike their inorganic counterparts, polymers combine complex repeat unit structure and crystalline disorder. This combination prevents any single technique from being able to uniquely solve the packing arrangement of the molecules. Here, a general methodology for combining multiple, complementary techniques that provide accurate unit cell dimensions and molecular orientation is described. The combination of measurements results in a nearly complete picture of the organic film morphology. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of Quantitative Antifungal Testing Methods for Textile Fabrics.

PubMed

Imoto, Yasuo; Seino, Satoshi; Nakagawa, Takashi; Yamamoto, Takao A

2017-01-01

　Quantitative antifungal testing methods for textile fabrics under growth-supportive conditions were studied. Fungal growth activities on unfinished textile fabrics and textile fabrics modified with Ag nanoparticles were investigated using the colony counting method and the luminescence method. Morphological changes of the fungi during incubation were investigated by microscopic observation. Comparison of the results indicated that the fungal growth activity values obtained with the colony counting method depended on the morphological state of the fungi on textile fabrics, whereas those obtained with the luminescence method did not. Our findings indicated that unique characteristics of each testing method must be taken into account for the proper evaluation of antifungal activity.

Morphogenesis by symbiogenesis

NASA Technical Reports Server (NTRS)

Chapman, M. J.; Margulis, L.

1998-01-01

Here we review cases where initiation of morphogenesis, including the differentiation of specialized cells and tissues, has clearly evolved due to cyclical symbiont integration. For reasons of space, our examples are drawn chiefly from the plant, fungal and bacterial kingdoms. Partners live in symbioses and show unique morphological specializations that result when they directly and cyclically interact. We include here brief citations to relevant literature where plant, bacterial or fungal partners alternate independent with entirely integrated living. The independent, or at least physically unassociated stages, are correlated with the appearance of distinctive morphologies that can be traced to the simultaneous presence and strong interaction of the plant with individuals that represent different taxa.

Modality effect in false recognition: evidence from Chinese characters.

PubMed

Mao, Wei Bin; Yang, Zhi Liang; Wang, Lin Song

2010-02-01

Using the Deese/Roediger-McDermott (DRM) false memory method, Smith and Hunt ( 1998 ) first reported the modality effect on false memory and showed that false recall from DRM lists was lower following visual study than following auditory study, which led to numerous studies on the mechanism of modality effect on false memory and provided many competing explanations. In the present experiment, the authors tested the modality effect in false recognition by using a blocked presentation condition and a random presentation condition. The present experiment found a modality effect different from the results of the previous research; namely, false recognition was shown to be greater following visual study than following auditory study, especially in the blocked presentation condition rather than in the random presentation condition. The authors argued that this reversed modality effect may be due to different encoding and processing characteristics between Chinese characters and English words. Compared with English words, visual graphemes of critical lures in Chinese lists are likely to be activated and encoded in participants' minds, thus it is more difficult for participants to discriminate later inner graphemes from those items presented in visual modality. Hence visual presentation could lead to more false recognition than auditory presentation in Chinese lists. The results in the present experiment demonstrated that semantic activation occurring during the encoding and retrieve phases played an important role in modality effect in false recognition, and our findings might be explained by the activation-monitoring account. Utilisant la méthode de fausse mémoire de Deese/Roediger-McDermott (DRM), Smith et Hunt ( 1998 ) ont d'abord rendu compte de l'effet de modalité sur la fausse mémoire et ils ont montré que le faux rappel à partir des listes de DRM était plus faible suivant une étude visuelle plutôt qu'une étude auditive. Ceci a mené à plusieurs études sur le mécanisme de l'effet de modalité sur la fausse mémoire, lesquelles ont fourni plusieurs explications concurrentes. Dans la présente expérience, les auteurs ont testé l'effet de modalité dans la fausse reconnaissance en utilisant une condition de présentation fixe et une condition de présentation aléatoire. Cette expérience a révélé un effet de modalité différent des résultats obtenus dans les recherches antérieures. En effet, la fausse reconnaissance était plus élevée suivant une étude visuelle plutôt qu'une étude auditive, spécialement dans la condition de présentation fixe. Les auteurs suggèrent que cet effet de modalité inverse peut être dû à des caractéristiques d'encodage et de processus différentes entre les caractères chinois et les mots anglais. Comparativement aux mots anglais, les graphèmes visuels des leurres critiques dans les listes chinoises sont susceptibles d'être activés et encodés dans l'esprit des participants, rendant plus difficile de discriminer les graphèmes intériorisés plus tard de ces items présentés dans la modalité visuelle. Ainsi, la présentation visuelle pourrait mener à davantage de fausse reconnaissance que la présentation auditive dans les listes chinoises. Les résultats de la présente expérience ont démontré que l'activation sémantique se produisait durant l'encodage et que la phase de retrait jouait un rôle important dans l'effet de modalité dans la fausse reconnaissance. Nos résultats peuvent être expliqués par la théorie activation-contrôle. Utilizando el método de Deese/Roediger-McDermott (DRM) de falsa mamoria, Smith y Hunt ( 1998 ) fueron los primeros en encontrar el efecto de modalidad en la falsa memoria y demostraron que los falsos recuerdos del listado DRM fueron más bajos después de un estudio visual que después de un estudio auditivo lo cual llevó a varios estudios sobre el mecanismo del efecto de la modalidad sobre falsos recuerdos y proporcionó varias explicaciones que compiten entre sí. En el presente trabajo, los autores estudiaron el efecto de la modalidad en el falso reconocimiento utilizando una condición de presentación en bloques y otra condición de presentación de forma aleatoria. El presente experimento encontró un efecto de la modalidad diferente de los resultados de los estudios anteriores. En concreto, el reconocimiento falso ha resultado ser mayor después del estudio visual que después del estudio auditivo, especialmente en caso de la presentación en bloques en comparación con la condición de presentación aleatoria. Los autores argumentan que este efecto inverso de la modalidad puede ser causado por diferentes características de codificación y procesamiento entre caracteres chinos y palabras inglesas. En comparación con las palabras inglesas, los grafemas visuales de las palabras críticas en chino tienen probabilidad de ser activadas y codificadas en las mentes de los participantes, por tanto, es más difícil discriminar posteriores grafemas internos de los que fueron presentados en la modalidad visual. Por tanto, la presentación visual podría conducir a más falsos reconocimientos que la presentación auditiva en los listados de palabras chinas. Los resultados del presente experimento demostraron que la activación semántica durante las fases de codificación y recuperación jugó un rol importante en el efecto de falso reconocimiento según modalidad y que nuestros resultados se pueden explicar teniendo en cuenta la activación y la vigilancia.

Pharmacothérapie de la dépression chez les aînés

PubMed Central

Frank, Christopher

2014-01-01

Résumé Objectif Discuter du traitement pharmacologique de la dépression chez les personnes âgées, y compris le choix des antidépresseurs, le titrage de la dose, la surveillance de la réponse et des effets secondaires et le traitement des cas réfractaires. Sources des données Les lignes directrices de 2006 de la Canadian Coalition for Seniors’ Mental Health sur l’évaluation et le traitement de la dépression ont servi comme source principale. Pour recenser les articles publiés après les lignes directrices, on a procédé à une recherche documentaire dans MEDLINE de 2007 à 2012 à l’aide des expressions en anglais depression, treatment, drug therapy et elderly. Message principal Le but du traitement devrait être la rémission des symptômes. L’amélioration des symptômes peut être surveillée en fonction des objectifs du patient qu’on a identifiés ou en se servant d’outils cliniques comme le Patient Health Questionnaire–9. On devrait envisager le traitement en 3 étapes: l’étape du traitement aigu pour obtenir la rémission des symptômes, une étape de continuation pour prévenir la récurrence d’un même épisode de la maladie (rechute) et une étape de maintien (prophylaxie) pour prévenir de futurs épisodes (récurrence). Le dosage initial devrait être la moitié de la dose de départ habituelle chez l’adulte et il devrait être titré régulièrement jusqu’à ce que le patient réponde, jusqu’à ce que la dose maximale soit atteinte ou encore que les effets secondaires en limitent l’augmentation. Parmi les effets secondaires fréquents, on peut mentionner les chutes, la nausée, les étourdissements, les céphalées et, moins communément, l’hyponatrémie et des changements dans l’intervalle QT. Des stratégies pour changer ou augmenter les antidépresseurs sont présentées. Les patients plus âgés devraient être traités pendant au moins un an à compter de l’observation d’une amélioration clinique et ceux qui ont une dépression récurrente ou des symptômes sévères devraient continuer le traitement indéfiniment. La prise en charge de situations particulières comme une dépression profonde ou une dépression avec psychose est discutée, y compris le recours à une thérapie électroconvulsive. Les critères pour demander une consultation en psychiatrie gériatrique sont indiqués; par ailleurs, de nombreux médecins de famille n’ont pas aisément accès à une telle ressource ou à d’autres stratégies cliniques non pharmacologiques. Conclusion L’efficacité de la pharmacothérapie de la dépression n’est pas considérablement influencée par l’âge. L’identification de la dépression, le choix du traitement approprié, le tritrage des médicaments, la surveillance des effets secondaires et la durée suffisante du traitement amélioreront les résultats pour les patients plus âgés.

Developpement et validation d'un outil base sur l'acoustique geometrique pour le diagnostic du bruit de nacelle

NASA Astrophysics Data System (ADS)

Minard, Benoit

De nos jours, la problématique du bruit généré par les avions est devenue un point de développement important dans le domaine de l'aéronautique. C'est ainsi que de nombreuses études sont faites dans le domaine et une première approche consiste à modéliser de façon numérique ce bruit de manière à réduire de façon conséquente les coûts lors de la conception. C'est dans ce contexte qu'un motoriste a demandé à l'université de Sherbrooke, et plus particulièrement au groupe d'acoustique de l'Université de Sherbrooke (GAUS), de développer un outil de calcul de la propagation des ondes acoustiques dans les nacelles mais aussi pour l'étude des effets d'installation. Cet outil de prédiction leur permet de réaliser des études afin d'optimiser les traitements acoustiques (« liners »), la géométrie de ces nacelles pour des études portant sur l'intérieur de la nacelle et des études de positionnement des moteurs et de design pour les effets d'installation. L'objectif de ce projet de maîtrise était donc de poursuivre le travail réalisé par [gousset, 2011] sur l'utilisation d'une méthode de lancer de rayons pour l'étude des effets d'installation des moteurs d'avion. L'amélioration du code, sa rapidité, sa fiabilité et sa généralité étaient les objectifs principaux. Le code peut être utilisé avec des traitements acoustiques de surfaces («liners») et peut prendre en compte le phénomène de la diffraction par les arêtes et enfin peut être utilisé pour réaliser des études dans des environnements complexes tels que les nacelles d'avion. Le code développé fonctionne en 3D et procéde en 3 étapes : (1) Calcul des faisceaux initiaux (division d'une sphère, demi-sphère, maillage des surfaces de la géométrie) (2) Propagation des faisceaux dans l'environnement d'étude : calcul de toutes les caractéristiques des rayons convergents (amplitude, phase, nombre de réflexions, ...) (3) Reconstruction du champ de pression en un ou plusieurs points de l'espace à partir de rayons convergents (sommation des contributions de chaque rayon) : sommation cohérente. Le code (GA3DP) permet de prendre en compte les traitements de surface des parois, la directivité de la source, l'atténuation atmosphérique et la diffraction d'ordre 1. Le code a été validé en utilisant différentes méthodes telles que la méthode des sources-images, la méthode d'analyse modale ou encore la méthode des éléments finis de frontière. Un module Matlab a été créé spécialement pour l'étude des effets d'installation et intégré au code existant chez Pratt & Whitney Canada. Mots-clés : Acoustique géométrique - Ray-Tracing - Lancer de faisceaux - Diffraction - Sommation Cohérente - Niveau de Pression.

Solidification and Morphological Evolution of Al-Si Eutectics in Convector-Diffusive Conditions

NASA Technical Reports Server (NTRS)

Singh, N. B.; Su, Ching Hua; Arnold, Brad; Choa, Fow-Sen; Mandal, K. D.

2017-01-01

The Al-Si material system is an important and has been studied for over half century with a focus on industrial applications in high strength and high conductivity alloys. A great deal of researches have been focused on controlling the morphology and hence performance through the addition of small impurities and by processing conditions. Most of the structure-property correlations are based on the post solidified micromorphology and growth conditions. This material system is unique and has been explored for heat spreader, controlling coefficient of expansion by adjusting composition of silicon and in designing composites. The Al-Si system is very interesting system for understanding the dendritic (Al-rich side) eutectic transition. Recently this system has been of great interest because of its applications in designing heat spreader, low temperature flux to grow SiC large substrates and in controlling the coefficient of expansion of Al-based alloys. We have performed extensive experiments to understand eutectic transition and to understand the morphological evolution in presence of impurities. We will discuss the results of dendritic transition into faceted long grains in convector-diffusive conditions. In this presentation we will present morphological transition in presence of carbon impurity and development of novel morphology.

Controlling the Morphology of Side Chain Liquid Crystalline Block Copolymer Thin Films through Variations in Liquid Crystalline Content

PubMed Central

Verploegen, Eric; Zhang, Tejia; Jung, Yeon Sik; Ross, Caroline; Hammond, Paula T.

2009-01-01

In this paper we describe methods for manipulating the morphology of side-chain liquid crystalline block copolymers through variations in the liquid crystalline content. By systematically controlling the covalent attachment of side chain liquid crystals to a block copolymer (BCP) backbone, the morphology of both the liquid crystalline (LC) mesophase and the phase segregated BCP microstructures can be precisely manipulated. Increases in LC functionalization lead to stronger preferences for the anchoring of the LC mesophase relative to the substrate and the inter-material dividing surface (IMDS). By manipulating the strength of these interactions the arrangement and ordering of the ultrathin film block copolymer nanostructures can be controlled, yielding a range of morphologies that includes perpendicular and parallel cylinders, as well as both perpendicular and parallel lamellae. Additionally, we demonstrate the utilization of selective etching to create a nanoporous liquid crystalline polymer thin film. The unique control over the orientation and order of the self-assembled morphologies with respect to the substrate will allow for the custom design of thin films for specific nano-patterning applications without manipulation of the surface chemistry or the application of external fields. PMID:18763835

TiO2 nanofibers resembling 'yellow bristle grass' in morphology by a soft chemical transformation.

PubMed

Nandan, Sandeep; Deepak, T G; Nair, Shantikumar V; Nair, A Sreekumaran

2015-05-28

We synthesized a uniquely shaped one-dimensional (1-D) TiO2 nanostructure having the morphology of yellow bristle grass with high surface area by the titanate route under mild reaction conditions. The electrospun TiO2-SiO2 composite nanofibers upon treatment with concentrated NaOH at 80 °C under ambient pressure for 24 h resulted in sodium titanate (Na2Ti3O7) nanostructures. The Na2Ti3O7 nanostructures have an overall 1-D fibrous morphology but the highly porous fiber surfaces were decorated with layered thorn-like features (a morphology resembling that of yellow bristle grass) resulting in high surface area (113 m(2) g(-1)) and porosity. The Na2Ti3O7 nanostructures were converted into TiO2 nanostructures of the same morphology by acidification (0.1 N HCl) followed by low temperature sintering (110 °C) processes. Dye-sensitized solar cells (DSCs) constructed out of the material (cells of area 0.20 cm(2) and thickness 12 μm) showed a power conversion efficiency (η) of 8.02% in comparison with commercial P-25 TiO2 (η = 6.1%).

Morphological biosignatures and the search for life on Mars.

PubMed

Cady, Sherry L; Farmer, Jack D; Grotzinger, John P; Schopf, J William; Steele, Andrew

2003-01-01

This report provides a rationale for the advances in instrumentation and understanding needed to assess claims of ancient and extraterrestrial life made on the basis of morphological biosignatures. Morphological biosignatures consist of bona fide microbial fossils as well as microbially influenced sedimentary structures. To be recognized as evidence of life, microbial fossils must contain chemical and structural attributes uniquely indicative of microbial cells or cellular or extracellular processes. When combined with various research strategies, high-resolution instruments can reveal such attributes and elucidate how morphological fossils form and become altered, thereby improving the ability to recognize them in the geological record on Earth or other planets. Also, before fossilized microbially influenced sedimentary structures can provide evidence of life, criteria to distinguish their biogenic from non-biogenic attributes must be established. This topic can be advanced by developing process-based models. A database of images and spectroscopic data that distinguish the suite of bona fide morphological biosignatures from their abiotic mimics will avoid detection of false-positives for life. The use of high-resolution imaging and spectroscopic instruments, in conjunction with an improved knowledge base of the attributes that demonstrate life, will maximize our ability to recognize and assess the biogenicity of extraterrestrial and ancient terrestrial life.

Controlling the morphology of side chain liquid crystalline block copolymer thin films through variations in liquid crystalline content.

PubMed

Verploegen, Eric; Zhang, Tejia; Jung, Yeon Sik; Ross, Caroline; Hammond, Paula T

2008-10-01

In this paper, we describe methods for manipulating the morphology of side-chain liquid crystalline block copolymers through variations in the liquid crystalline content. By systematically controlling the covalent attachment of side chain liquid crystals to a block copolymer (BCP) backbone, the morphology of both the liquid crystalline (LC) mesophase and the phase-segregated BCP microstructures can be precisely manipulated. Increases in LC functionalization lead to stronger preferences for the anchoring of the LC mesophase relative to the substrate and the intermaterial dividing surface. By manipulating the strength of these interactions, the arrangement and ordering of the ultrathin film block copolymer nanostructures can be controlled, yielding a range of morphologies that includes perpendicular and parallel cylinders, as well as both perpendicular and parallel lamellae. Additionally, we demonstrate the utilization of selective etching to create a nanoporous liquid crystalline polymer thin film. The unique control over the orientation and order of the self-assembled morphologies with respect to the substrate will allow for the custom design of thin films for specific nanopatterning applications without manipulation of the surface chemistry or the application of external fields.

Genetic and morphological diversity of Trisetacus species (Eriophyoidea: Phytoptidae) associated with coniferous trees in Poland: phylogeny, barcoding, host and habitat specialization.

PubMed

Lewandowski, Mariusz; Skoracka, Anna; Szydło, Wiktoria; Kozak, Marcin; Druciarek, Tobiasz; Griffiths, Don A

2014-08-01

Eriophyoid species belonging to the genus Trisetacus are economically important as pests of conifers. A narrow host specialization to conifers and some unique morphological characteristics have made these mites interesting subjects for scientific inquiry. In this study, we assessed morphological and genetic variation of seven Trisetacus species originating from six coniferous hosts in Poland by morphometric analysis and molecular sequencing of the mitochondrial cytochrome oxidase subunit I gene and the nuclear D2 region of 28S rDNA. The results confirmed the monophyly of the genus Trisetacus as well as the monophyly of five of the seven species studied. Both DNA sequences were effective in discriminating between six of the seven species tested. Host-dependent genetic and morphological variation in T. silvestris and T. relocatus, and habitat-dependent genetic and morphological variation in T. juniperinus were detected, suggesting the existence of races or even distinct species within these Trisetacus taxa. This is the first molecular phylogenetic analysis of the Trisetacus species. The findings presented here will stimulate further investigations on the evolutionary relationships of Trisetacus as well as the entire Phytoptidae family.

Janus and Strawberry-like Particles from Azo Molecular Glass and Polydimethylsiloxane Oligomer.

PubMed

Hsu, Chungen; Du, Yi; Wang, Xiaogong

2017-10-10

This study investigated Janus and strawberry-like particles composed of azo molecular glass and polydimethylsiloxane (PDMS) oligomer, focusing on controllable fabrication and formation mechanism of these unique structures and morphologies. Two materials, the azo molecular glass (IA-Chol) and PDMS oligomer (H 2 pdca-PDMS), were prepared for this purpose. The Janus and strawberry-like particles were obtained from the droplets of a dichloromethane (DCM) solution containing both IA-Chol and H 2 pdca-PDMS, dispersed in water and stabilized by poly(vinyl alcohol). Results show that the structured particles are formed through segregation between the two components induced by gradual evaporation of DCM from the droplets, which is controlled by adding ethylene glycol (EG) into the above dispersion. Without the addition of EG, Janus particles are formed through the full segregation of the two components in the droplets. On the other hand, with the existence of EG in the dispersion, strawberry-like particles instead of Janus particles are formed in the phase separation process. The diffusion of EG molecules from the dispersion medium into the droplets causes the PDMS phase deswelling in the interfacial area due to the poor solvent effect. Caused by the surface coagulation, the coalescence of the isolated IA-Chol domains is jammed in the shell region, which results in the formation of the strawberry-like particles. For the particles separated from the dispersion and dried, the PDMS oligomer phase of the Janus particles can adhere and spread on the substrate to form unique "particle-on-pad" morphology due to its low surface energy and swelling ability, while the strawberry-like particles exist as "standstill" objects on the substrates. Upon irradiation with a linearly polarized laser beam at 488 nm, the azo molecular glass parts in the particles are significantly deformed along the light polarization direction, which show unique and distinct morphologies for these two types of the particles.

Differential expression of Meis2, Mab21l2 and Tbx3 during limb development associated with diversification of limb morphology in mammals.

PubMed

Dai, Mengyao; Wang, Yao; Fang, Lu; Irwin, David M; Zhu, Tengteng; Zhang, Junpeng; Zhang, Shuyi; Wang, Zhe

2014-01-01

Bats are the only mammals capable of self-powered flight using wings. Differing from mouse or human limbs, four elongated digits within a broad wing membrane support the bat wing, and the foot of the bat has evolved a long calcar that spread the interfemoral membrane. Our recent mRNA sequencing (mRNA-Seq) study found unique expression patterns for genes at the 5' end of the Hoxd gene cluster and for Tbx3 that are associated with digit elongation and wing membrane growth in bats. In this study, we focused on two additional genes, Meis2 and Mab21l2, identified from the mRNA-Seq data. Using whole-mount in situ hybridization (WISH) we validated the mRNA-Seq results for differences in the expression patterns of Meis2 and Mab21l2 between bat and mouse limbs, and further characterize the timing and location of the expression of these two genes. These analyses suggest that Meis2 may function in wing membrane growth and Mab21l2 may have a role in AP and DV axial patterning. In addition, we found that Tbx3 is uniquely expressed in the unique calcar structure found in the bat hindlimb, suggesting a role for this gene in calcar growth and elongation. Moreover, analysis of the coding sequences for Meis2, Mab21l2 and Tbx3 showed that Meis2 and Mab21l2 have high sequence identity, consistent with the functions of genes being conserved, but that Tbx3 showed accelerated evolution in bats. However, evidence for positive selection in Tbx3 was not found, which would suggest that the function of this gene has not been changed. Together, our findings support the hypothesis that the modulation of the spatiotemporal expression patterns of multiple functional conserved genes control limb morphology and drive morphological change in the diversification of mammalian limbs.

Differential Expression of Meis2, Mab21l2 and Tbx3 during Limb Development Associated with Diversification of Limb Morphology in Mammals

PubMed Central

Fang, Lu; Irwin, David M.; Zhu, Tengteng; Zhang, Junpeng; Zhang, Shuyi; Wang, Zhe

2014-01-01

Bats are the only mammals capable of self-powered flight using wings. Differing from mouse or human limbs, four elongated digits within a broad wing membrane support the bat wing, and the foot of the bat has evolved a long calcar that spread the interfemoral membrane. Our recent mRNA sequencing (mRNA-Seq) study found unique expression patterns for genes at the 5′ end of the Hoxd gene cluster and for Tbx3 that are associated with digit elongation and wing membrane growth in bats. In this study, we focused on two additional genes, Meis2 and Mab21l2, identified from the mRNA-Seq data. Using whole-mount in situ hybridization (WISH) we validated the mRNA-Seq results for differences in the expression patterns of Meis2 and Mab21l2 between bat and mouse limbs, and further characterize the timing and location of the expression of these two genes. These analyses suggest that Meis2 may function in wing membrane growth and Mab21l2 may have a role in AP and DV axial patterning. In addition, we found that Tbx3 is uniquely expressed in the unique calcar structure found in the bat hindlimb, suggesting a role for this gene in calcar growth and elongation. Moreover, analysis of the coding sequences for Meis2, Mab21l2 and Tbx3 showed that Meis2 and Mab21l2 have high sequence identity, consistent with the functions of genes being conserved, but that Tbx3 showed accelerated evolution in bats. However, evidence for positive selection in Tbx3 was not found, which would suggest that the function of this gene has not been changed. Together, our findings support the hypothesis that the modulation of the spatiotemporal expression patterns of multiple functional conserved genes control limb morphology and drive morphological change in the diversification of mammalian limbs. PMID:25166052

Technical Evaluation Report on the Fluid Dynamics Panel Specialists’ Meeting on Effects of Adverse Weather on Aerodynamics (Les Effets des Conditions Meteorologiques Adverses sur l’Aerodynamique)

DTIC Science & Technology

1991-11-01

AD-A245 117 III~i~IIiiIiIIi~ifhII _________________________AGARD-R306 0 AGARD ADVISORY GROUP FOR AEROSPACE RESEARCH & DEVELOPMENT 4 7 RUE ANCELLE...REPRODUCE LEGIBLY. AGARD-AR-306 ADVISORY GROUP FOR AEROSPACE RESEARCH & DEVELOPMENT 7 RUE ANCELLE 92200 NEUILLY SUR SEINE FRANCE AGARD ADVISORY RIEPORT...Conditions NMeleorolovioiue,, Adverscs sur rAerodynarminiuc) - J.J. Reinrnann National ,\\cronautico and Space .\\drmintration L eip Research (Center

L'effet de la mise en page d'un livre sur le pairage du texte et de l'illustration par le jeune lecteur (The Effect of Book Layout on the Linking of Text and Illustrations by the Young Reader).

ERIC Educational Resources Information Center

Reinwein, Joachim

A study investigated the degree to which the page layout of a book affects the young reader's association of text with appropriate illustrations. Four hundred native French-speaking third-graders in eight Montreal (Canada) schools participated. In a third-grade text about animals, the names of the animals illustrated in pictures and other words…

CFD Simulations of a Ferry in Head Seas

DTIC Science & Technology

2011-03-01

la durée de vie en fatigue globale du navire. Il est important, pour la conception, l’exploitation et la gestion du cycle de ...vibration de frottement qui exerce une contrainte sur la structure de coque primaire et qui a un effet défavorable sur la durée de vie en fatigue globale du ...laquelle ne peut simuler directement la physique du tossage. Le présent rapport contient les résultats d’une étude faisant

Real-Time Adaptive Control of Mixing in a Plane Shear Layer

DTIC Science & Technology

1994-02-02

l’icoulement d’un fuide visqueux incompressible autour d’un cylinder fixe ou en rotation. Effet Magnus . J. Mdc. 14, 109-134. TANEDA, S. 1977 Visual study...Mokhtarian & Yokomizo 1990), and in lift enhancement schemes employing the Magnus effect (Swanson 1961). Rotation of all or part of a body may also have...coordinate system. In this work, the body-fitted grid is simply one of cylindrical polar coordinates and is time-independent, except for a = 3.25 where

RTO Meeting Proceedings 16, Aircraft Weapon System Compatibility and Integration held in Chester, United Kingdom, 28-30 September, 1998

DTIC Science & Technology

1999-04-01

project, there was a requirement to place a camera behind a each photogrammetric target in the image and for each cylindrically curved window...testing. T by the wind tunnel’s captive trajectory sting, U.S. wing open effets on the o erthnd, h e Navyengneer h e obervd sgnifcan difereces wing...Flying Qualities, Symposium on Aeroballistics, May 1981. Aerodynamics, and Structures disciplines benefit directly 6. Magnus , A. E., and Epton, M. A

Development of the Wake Behind a Circular Cylinder Impulsively Started into Rotatory and Rectilinear Motion: Intermediate Rotation Rates

DTIC Science & Technology

1991-01-01

cylindre fixe ou en rotation. Effet Magnus . J. Mec. 14, 109-134. Taneda, S. 1977 Visual study of unsteady separated flows around bodies. Prog. Aero...enhancement schemes employing the Magnus effect (Swanson 1961). Rotating all or part of a body may also have applications in active or feedback control of...and yt into the governing equations in the generalized coordinate system. In this study, the body-fitted grid is simply one of cylindrical polar

AFTERRISE: Deep Body Temperature Following Exercise

DTIC Science & Technology

1992-04-01

Egalement, les effets de la posture et des v~tements durant la r~cup~ration et la temperature de la salle de r~cup~ration furent examines. Cinq hommes...une chemise a manches courtes). Les tempdratures rectales et de la peau furent mesurdes & chaque minute durant les exercices et la r6cupdration...Ndcnillll~ l OLen 1+ 1DNfnce na~on~e :x DTIC Ss ELECTE FEB 5 1993DI C AFTERRISE: DEEP BODY TEMPERATURE FOLLOWING EXERCISE (U) by S. Tuck and A.A

Why Cold-Wet Makes One Feel Chilled: A Literature Review

DTIC Science & Technology

1988-06-01

froid et mouill6. On examine aussi l’effet de la radiation solaire , l’interaction entre la peau at l’humidit6, entre la peau et la temp~rature de mgme...directions, including back out into space. Aerosols of water in clouds reflect incident solar energy . The upper surface of a stratus cloud cover can reflect...earth than under clear conditions. Albedo, the fraction of the incident energy which is reflected by a surface, varies considerably with the terrain

Hygrothermal Effects in Continuous Fibre Reinforced Composites. Part 4. Mechanical Properties 2 - Fatigue and Time-Dependent Properties (Effets Hygrothermiques dans les Composites a Renfort de Fibre Continu. Partie 4. Proprietes Mecaniques 2 - Fatigue et Proprietes Dependant du Temps)

DTIC Science & Technology

1983-09-01

reduction of stress intensity at a crack tip due to Lreep was responsible for increasing the fatigue life during the "slow- fast " L .sts. As creep is clearly...Aeronautical Establishment Structures and Materials Laboratory SPONSORING AGENCY/AGENCE DE SUBVENTION 8 DATE FILE/DOSSIER LAB. ORDER PAGES FIGS/ DIAGRAMMES

Relativité générale et gravitation.

NASA Astrophysics Data System (ADS)

Elbaz, E.

Contents: 1. Description de l'univers observable. 2. Lemicro-univers des particules élémentaires. 3. Analyse tensorielle.4. Relativité restreinte. 5. Effet de la gravitation en relativité générale. 6. Équations d'Einstein. 7. Ondes gravitationnelles. 8. Champ de gravitation statique et isotrope. 9. Structures stellaires. 10. Champ de gravitation non statique isotrope. 11. Introduction à la dynamique cosmologique et au modèle standard de l'univers très primitif. 12. Perspectives actuelles.

Light and Electron Microscopy of the European Beaver (Castor fiber) Stomach Reveal Unique Morphological Features with Possible General Biological Significance

PubMed Central

Petryński, Wojciech; Palkowska, Katarzyna; Prusik, Magdalena; Targońska, Krystyna; Giżejewski, Zygmunt; Przybylska-Gornowicz, Barbara

2014-01-01

Anatomical, histological, and ultrastructural studies of the European beaver stomach revealed several unique morphological features. The prominent attribute of its gross morphology was the cardiogastric gland (CGG), located near the oesophageal entrance. Light microscopy showed that the CGG was formed by invaginations of the mucosa into the submucosa, which contained densely packed proper gastric glands comprised primarily of parietal and chief cells. Mucous neck cells represented <0.1% of cells in the CGG gastric glands and 22–32% of cells in the proper gastric glands of the mucosa lining the stomach lumen. These data suggest that chief cells in the CGG develop from undifferentiated cells that migrate through the gastric gland neck rather than from mucous neck cells. Classical chief cell formation (i.e., arising from mucous neck cells) occurred in the mucosa lining the stomach lumen, however. The muscularis around the CGG consisted primarily of skeletal muscle tissue. The cardiac region was rudimentary while the fundus/corpus and pyloric regions were equally developed. Another unusual feature of the beaver stomach was the presence of specific mucus with a thickness up to 950 µm (in frozen, unfixed sections) that coated the mucosa. Our observations suggest that the formation of this mucus is complex and includes the secretory granule accumulation in the cytoplasm of pit cells, the granule aggregation inside cells, and the incorporation of degenerating cells into the mucus. PMID:24727802

Phylogenetic Relationships and Species Delimitation in Pinus Section Trifoliae Inferrred from Plastid DNA

PubMed Central

Hernández-León, Sergio; Gernandt, David S.; Pérez de la Rosa, Jorge A.; Jardón-Barbolla, Lev

2013-01-01

Recent diversification followed by secondary contact and hybridization may explain complex patterns of intra- and interspecific morphological and genetic variation in the North American hard pines (Pinus section Trifoliae), a group of approximately 49 tree species distributed in North and Central America and the Caribbean islands. We concatenated five plastid DNA markers for an average of 3.9 individuals per putative species and assessed the suitability of the five regions as DNA bar codes for species identification, species delimitation, and phylogenetic reconstruction. The ycf1 gene accounted for the greatest proportion of the alignment (46.9%), the greatest proportion of variable sites (74.9%), and the most unique sequences (75 haplotypes). Phylogenetic analysis recovered clades corresponding to subsections Australes, Contortae, and Ponderosae. Sequences for 23 of the 49 species were monophyletic and sequences for another 9 species were paraphyletic. Morphologically similar species within subsections usually grouped together, but there were exceptions consistent with incomplete lineage sorting or introgression. Bayesian relaxed molecular clock analyses indicated that all three subsections diversified relatively recently during the Miocene. The general mixed Yule-coalescent method gave a mixed model estimate of only 22 or 23 evolutionary entities for the plastid sequences, which corresponds to less than half the 49 species recognized based on morphological species assignments. Including more unique haplotypes per species may result in higher estimates, but low mutation rates, recent diversification, and large effective population sizes may limit the effectiveness of this method to detect evolutionary entities. PMID:23936218

Characterization of hydrogen responsive nanoporous palladium films synthesized via a spontaneous galvanic displacement reaction.

PubMed

Patton, J F; Lavrik, N V; Joy, D C; Hunter, S R; Datskos, P G; Smith, D B; Sepaniak, M J

2012-11-23

A model is presented regarding the mechanistic properties associated with the interaction of hydrogen with nanoporous palladium (np-Pd) films prepared using a spontaneous galvanic displacement reaction (SGDR), which involves PdCl(2) reduction by atomic Ag. Characterization of these films shows both chemical and morphological factors, which influence the performance characteristics of np-Pd microcantilever (MC) nanomechanical sensing devices. Raman spectroscopy, uniquely complemented with MC response profiles, is used to explore the chemical influence of palladium oxide (PdO). These combined techniques support a reaction mechanism that provides for rapid response to H(2) and recovery in the presence of O(2). Post-SGDR processing via reduction of PdCl(2)(s) in a H(2) environment results in a segregated nanoparticle three-dimensional matrix dispersed in a silver layer. The porous nature of the reduced material is shown by high resolution scanning electron microscopy. Extended grain boundaries, typical of these materials, result in a greater surface area conducive to fast sorption/desorption of hydrogen, encouraged by the presence of PdO. X-ray diffraction and inductively coupled plasma-optical emission spectroscopy are employed to study changes in morphology and chemistry occurring in these nanoporous films under different processing conditions. The unique nature of chemical/morphological effects, as demonstrated by the above characterization methods, provides evidence in support of observed nanomechanical response/recovery profiles offering insight for catalysis, H(2) storage and improved sensing applications.

Cyanobacteria in lakes on Yungui Plateau, China are assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use

PubMed Central

Liao, Jingqiu; Zhao, Lei; Cao, Xiaofeng; Sun, Jinhua; Gao, Zhe; Wang, Jie; Jiang, Dalin; Fan, Hao; Huang, Yi

2016-01-01

Plateau lakes are important ecosystems with diverse ecological functions. Cyanobacteria play a key role in plateau lakes as primary producers. However, they are threatening when dense blooms occur. Identifying cyanobacteiral biogeography and the mechanism of assembly processes shaping the distribution of cyanobacteria in plateau lakes is critical for understanding cyanobacterial ecology and applying it to lake management. In the present study, the biogeographic pattern and importance of neutral and niche processes in assembly of cyanobacteria in 21 lakes on Yungui Plateau, China were examined. Results showed that cyanobacteria exhibit unique biogeographic pattern, and most of them have a narrow habitat preference in plateau lakes. They were assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use, which explained 62.4% of the biological variation. Neutral processes were not at play. Water physicochemical property (key variables - dissolved oxygen, salinity, trophic status and pH) was the most dominant driver shaping its unique biogeographic pattern. Watershed land-use especially urban land, water body and agricultural land also exhibited a strong impact on cyanobacterial distribution, followed by lake morphology. As most of the cyanobacteiral genus detected in these plateau lakes were potential toxin-producers, this study indicated that in order to protect waters from toxic-bloom in the future, reducing nutrient loading and land-use practices are two practical approaches in plateau lake management. PMID:27819304

Morphology of single inhalable particle in the air polluted city of Shijiazhuang, China.

PubMed

Wang, Zanhong; Zhang, Lingzhi; Zhang, Yuliang; Zhao, Zhou; Zhang, Sumin

2008-01-01

In the typical air polluted city of Shijiazhuang, single inhalable particle samples in non-heating period, heating period, dust storm days, and snowy days were collected and detected by SEM/EDS (scanning electron microscopy and energy dispersive X-ray spectrometry). The particle morphology was characterized by the 6 shape clusters, which are: irregular square, agglomerate, sphere, floccule, column or stick, and unknown, by quantitative order. The irregular square particles are common in all kinds of samples; sphere particles are more, and column or stick are less in winter samples; in the wet deposit samples, agglomerate and floccule particles are not found. The surface of most particles is coarse with fractal edge, which can provide suitable chemical reaction bed in the polluted atmospheric environment. New formed calcium crystal is found to demonstrate the existence of neutralized reaction, explaining the reason for the high SO2 emission and low acid rain frequency in Shijiazhuang. The three sorts of surface patterns of spheres are smooth, semi-smooth, and coarse, corresponding to the element of Si-dominant, Si-Al-dominant, and Fe-dominant. The soot particle is present as floccule with average size around 10 microm, considerably larger than the former reported results, but wrapped or captured with other fine particles to make its appearance unique and enhance its toxicity potentially. The new formed calcium crystal, the 3 sorts of sphere surface patterns, and the unique soot appearance represent the single inhalable particle's morphology characteristics in Shijiazhuang City.

Cyanobacteria in lakes on Yungui Plateau, China are assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use

NASA Astrophysics Data System (ADS)

Liao, Jingqiu; Zhao, Lei; Cao, Xiaofeng; Sun, Jinhua; Gao, Zhe; Wang, Jie; Jiang, Dalin; Fan, Hao; Huang, Yi

2016-11-01

Plateau lakes are important ecosystems with diverse ecological functions. Cyanobacteria play a key role in plateau lakes as primary producers. However, they are threatening when dense blooms occur. Identifying cyanobacteiral biogeography and the mechanism of assembly processes shaping the distribution of cyanobacteria in plateau lakes is critical for understanding cyanobacterial ecology and applying it to lake management. In the present study, the biogeographic pattern and importance of neutral and niche processes in assembly of cyanobacteria in 21 lakes on Yungui Plateau, China were examined. Results showed that cyanobacteria exhibit unique biogeographic pattern, and most of them have a narrow habitat preference in plateau lakes. They were assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use, which explained 62.4% of the biological variation. Neutral processes were not at play. Water physicochemical property (key variables - dissolved oxygen, salinity, trophic status and pH) was the most dominant driver shaping its unique biogeographic pattern. Watershed land-use especially urban land, water body and agricultural land also exhibited a strong impact on cyanobacterial distribution, followed by lake morphology. As most of the cyanobacteiral genus detected in these plateau lakes were potential toxin-producers, this study indicated that in order to protect waters from toxic-bloom in the future, reducing nutrient loading and land-use practices are two practical approaches in plateau lake management.

Cyanobacteria in lakes on Yungui Plateau, China are assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use.

PubMed

Liao, Jingqiu; Zhao, Lei; Cao, Xiaofeng; Sun, Jinhua; Gao, Zhe; Wang, Jie; Jiang, Dalin; Fan, Hao; Huang, Yi

2016-11-07

Plateau lakes are important ecosystems with diverse ecological functions. Cyanobacteria play a key role in plateau lakes as primary producers. However, they are threatening when dense blooms occur. Identifying cyanobacteiral biogeography and the mechanism of assembly processes shaping the distribution of cyanobacteria in plateau lakes is critical for understanding cyanobacterial ecology and applying it to lake management. In the present study, the biogeographic pattern and importance of neutral and niche processes in assembly of cyanobacteria in 21 lakes on Yungui Plateau, China were examined. Results showed that cyanobacteria exhibit unique biogeographic pattern, and most of them have a narrow habitat preference in plateau lakes. They were assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use, which explained 62.4% of the biological variation. Neutral processes were not at play. Water physicochemical property (key variables - dissolved oxygen, salinity, trophic status and pH) was the most dominant driver shaping its unique biogeographic pattern. Watershed land-use especially urban land, water body and agricultural land also exhibited a strong impact on cyanobacterial distribution, followed by lake morphology. As most of the cyanobacteiral genus detected in these plateau lakes were potential toxin-producers, this study indicated that in order to protect waters from toxic-bloom in the future, reducing nutrient loading and land-use practices are two practical approaches in plateau lake management.

Substrate effect on the growth of monolayer dendritic MoS2 on LaAlO3 (100) and its electrocatalytic applications

NASA Astrophysics Data System (ADS)

Li, Cong; Zhang, Yu; Ji, Qingqing; Shi, Jianping; Chen, Zhaolong; Zhou, Xiebo; Fang, Qiyi; Zhang, Yanfeng

2016-09-01

In accommodating the rapid development of two-dimensional (2D) nanomaterials, chemical vapor deposition (CVD) has become a powerful tool for their batch production with desirable characteristics, such as high crystal quality, large domain size, and tunable domain shape. The crystallinity and morphology of the growth substrates usually play a crucial role in the CVD synthesis of high-quality monolayer MoS2, a kind of 2D layered material which has ignited huge interest in nanoelectronics, optoelectronics and energy harvesting, etc. Herein, by utilizing a low-pressure chemical vapor deposition (LPCVD) system, we demonstrate a regioselective synthesis of monolayer MoS2 on the corrugated single-crystal LaAlO3 (100) with twin crystal domains induced by the second-order phase transition. Unique dendritic morphologies with tunable nucleation densities were obtained in different regions of the undulated substrate, presenting a strong substrate modulation effect. Interestingly, the exposure of abundant active edge sites along with the rather high nucleation density makes the monolayer dendritic MoS2 a good electrocatalyst for hydrogen evolution reaction (HER), particularly featured by a rather high exchange current density (70.4 μA cm-2). Furthermore, uniform monolayer MoS2 films can also be obtained and transferred to arbitrary substrates. We believe that this work provides a new growth system for the controllable synthesis of 2D layered materials with unique dendritic morphologies, as well as its great application potential in energy conversion and harvesting.

Round and pointed-head grenadier fishes (Actinopterygii: Gadiformes) represent a single sister group: evidence from the complete mitochondrial genome sequences.

PubMed

Satoh, Takashi P; Miya, Masaki; Endo, Hiromitsu; Nishida, Mutsumi

2006-07-01

The gene order of mitochondrial genomes (mitogenomes) has been employed as a useful phylogenetic marker in various metazoan animals, because it may represent uniquely derived characters shared by members of monophyletic groups. During the course of molecular phylogenetic studies of the order Gadiformes (cods and their relatives) based on whole mitogenome sequences, we found that two deep-sea grenadiers (Squalogadus modificatus and Trachyrincus murrayi: family Macrouridae) revealed a unusually identical gene order (translocation of the tRNA(Leu (UUR))). Both are members of the same family, although their external morphologies differed so greatly (e.g., round vs. pointed head) that they have been placed in different subfamilies Macrouroidinae and Trachyrincinae, respectively. Additionally, we determined the whole mitogenome sequences of two other species, Bathygadus antrodes and Ventrifossa garmani, representing a total of four subfamilies currently recognized within Macrouridae. The latter two species also exhibited gene rearrangements, resulting in a total of three different patterns of unique gene order being observed in the four subfamilies. Partitioned Bayesian analysis was conducted using available whole mitogenome sequences from five macrourids plus five outgroups. The resultant trees clearly indicated that S. modificatus and T. murrayi formed a monophyletic group, having a sister relationship to other macrourids. Thus, monophyly of the two species with disparate head morphologies was corroborated by two different lines of evidence (nucleotide sequences and gene order). The overall topology of the present tree differed from any of the previously proposed, morphology-based phylogenetic hypotheses.

Structure and engineering of celluloses.

PubMed

Pérez, Serge; Samain, Daniel

2010-01-01

This chapter collates the developments and conclusions of many of the extensive studies that have been conducted on cellulose, with particular emphasis on the structural and morphological features while not ignoring the most recent results derived from the elucidation of unique biosynthetic pathways. The presentation of structural and morphological data gathered together in this chapter follows the historical development of our knowledge of the different structural levels of cellulose and its various organizational levels. These levels concern features such as chain conformation, chain polarity, chain association, crystal polarity, and microfibril structure and organization. This chapter provides some historical landmarks related to the evolution of concepts in the field of biopolymer science, which parallel the developments of novel methods for characterization of complex macromolecular structures. The elucidation of the different structural levels of organization opens the way to relating structure to function and properties. The chemical and biochemical methods that have been developed to dissolve and further modify cellulose chains are briefly covered. Particular emphasis is given to the facets of topochemistry and topoenzymology where the morphological features play a key role in determining unique physicochemical properties. A final chapter addresses what might be considered tomorrow's goal in amplifying the economic importance of cellulose in the context of sustainable development. Selected examples illustrate the types of result that can be obtained when cellulose fibers are no longer viewed as inert substrates, and when the polyhydroxyl nature of their surfaces, as well as their entire structural complexity, are taken into account. Copyright © 2010 Elsevier Inc. All rights reserved.

Phylogenetic relationships and species delimitation in pinus section trifoliae inferrred from plastid DNA.

PubMed

Hernández-León, Sergio; Gernandt, David S; Pérez de la Rosa, Jorge A; Jardón-Barbolla, Lev

2013-01-01

Recent diversification followed by secondary contact and hybridization may explain complex patterns of intra- and interspecific morphological and genetic variation in the North American hard pines (Pinus section Trifoliae), a group of approximately 49 tree species distributed in North and Central America and the Caribbean islands. We concatenated five plastid DNA markers for an average of 3.9 individuals per putative species and assessed the suitability of the five regions as DNA bar codes for species identification, species delimitation, and phylogenetic reconstruction. The ycf1 gene accounted for the greatest proportion of the alignment (46.9%), the greatest proportion of variable sites (74.9%), and the most unique sequences (75 haplotypes). Phylogenetic analysis recovered clades corresponding to subsections Australes, Contortae, and Ponderosae. Sequences for 23 of the 49 species were monophyletic and sequences for another 9 species were paraphyletic. Morphologically similar species within subsections usually grouped together, but there were exceptions consistent with incomplete lineage sorting or introgression. Bayesian relaxed molecular clock analyses indicated that all three subsections diversified relatively recently during the Miocene. The general mixed Yule-coalescent method gave a mixed model estimate of only 22 or 23 evolutionary entities for the plastid sequences, which corresponds to less than half the 49 species recognized based on morphological species assignments. Including more unique haplotypes per species may result in higher estimates, but low mutation rates, recent diversification, and large effective population sizes may limit the effectiveness of this method to detect evolutionary entities.

Complex Morphological Variability in Complex Evaporitic Systems: Thermal Spring Snails from the Chihuahuan Desert, Mexico

NASA Astrophysics Data System (ADS)

Tang, Carol M.; Roopnarine, Peter D.

2003-11-01

Thermal springs in evaporitic environments provide a unique biological laboratory in which to study natural selection and evolutionary diversification. These isolated systems may be an analogue for conditions in early Earth or Mars history. One modern example of such a system can be found in the Chihuahuan Desert of north-central Mexico. The Cuatro Cienegas basin hosts a series of thermal springs that form a complex of aquatic ecosystems under a range of environmental conditions. Using landmark-based morphometric techniques, we have quantified an unusually high level of morphological variability in the endemic gastropod Mexipyrgus from Cuatro Cienegas. The differentiation is seen both within and between hydrological systems. Our results suggest that this type of environmental system is capable of producing and maintaining a high level of morphological diversity on small spatial scales, and thus should be a target for future astrobiological research.

Morphology and Pattern Control of Diphenylalanine Self-Assembly via Evaporative Dewetting.

PubMed

Chen, Jiarui; Qin, Shuyu; Wu, Xinglong; Chu, And Paul K

2016-01-26

Self-assembled peptide nanostructures have unique physical and biological properties and promising applications in electrical devices and functional molecular recognition. Although solution-based peptide molecules can self-assemble into different morphologies, it is challenging to control the self-assembly process. Herein, controllable self-assembly of diphenylalanine (FF) in an evaporative dewetting solution is reported. The fluid mechanical dimensionless numbers, namely Rayleigh, Marangoni, and capillary numbers, are introduced to control the interaction between the solution and FF molecules in the self-assembly process. The difference in the film thickness reflects the effects of Rayleigh and Marangoni convection, and the water vapor flow rate reveals the role of viscous fingering in the emergence of aligned FF flakes. By employing dewetting, various FF self-assembled patterns, like concentric and spokelike, and morphologies, like strips and hexagonal tubes/rods, can be produced, and there are no significant lattice structural changes in the FF nanostructures.

The theropod furcula.

PubMed

Nesbitt, Sterling J; Turner, Alan H; Spaulding, Michelle; Conrad, Jack L; Norell, Mark A

2009-07-01

The furcula is a structure formed by the midline fusion of the clavicles. This is the element which is unique to theropods and is important for understanding the link between birds and other theropods. New specimens from basal theropods suggest that the furcula appeared very early in theropod history. We review furcula development, function, and morphology, as well as the anatomical terminology applied to it. Furcular morphology is highly variable in crown-group avians but is rather conserved among nonavian theropods. Here we review, or describe for the first time, the furculae in many nonavian theropods. Furculae occur in nearly all major clades of theropods, as shown by new theropod specimens from the Early Cretaceous of China and a close inspection of previously collected specimens. Informative phylogenetic characters pertaining to the furcula occur throughout Theropoda, though care should betake to consider taphonomic effects when describing furcular morphology. (c) 2009 Wiley-Liss, Inc.

Morphological and behavioral evidence of Batesian mimicry in nestlings of a lowland Amazonian bird.

PubMed

Londoño, Gustavo A; García, Duván A; Sánchez Martínez, Manuel A

2015-01-01

Because predation is the main cause of avian nest failure, selection should favor strategies that reduce the probability of nest predation. We describe apparent Batesian mimicry in the morphology and behavior of a Laniocera hypopyrra nestling. On hatching, the nestling had a distinctive bright orange color and modified feathers all over its body, and 6 days after hatching, it started to move its head very slowly from side to side (in a "caterpillar" movement) when disturbed. These traits gave it a resemblance to a hairy, aposematic caterpillar. This species has a long nestling period for its size (20 days), perhaps due to slow provisioning rates (about one feeding per hour). We argue that the slow growth rate, combined with high nest predation, favors the evolution of antipredation mechanisms such as the unique morphological and behavioral characteristics of L. hypopyrra nestlings.

Host Galaxy Morphologies Of Hard X-ray Selected AGN From The Swift BAT Survey

NASA Astrophysics Data System (ADS)

Koss, Michael; Mushotzky, R.; Veilleux, S.

2009-01-01

Surveys of AGN taken in the optical, UV, and soft X-rays miss an important population of obscured AGN only visible in the hard X-rays and mid-IR wavelengths. The SWIFT BAT survey in the hard X-ray range (14-195 keV) has provided a uniquely unbiased sample of 258 AGN unaffected by galactic or circumnuclear absorption. Optical imaging of this unbiased sample provides a new opportunity to understand how the environments of the host galaxies are linked to AGN. For these host galaxies, only a fraction, 29%, have high quality optical images, predominately from the SDSS. In addition, about 33% show peculiar morphologies and interaction. In 2008, we observed 110 of these targets at Kitt Peak with the 2.1m in the SDSS bands over 17 nights. Using these observations and SDSS data we review the relationships between color, morphology, merger activity, star formation, and AGN luminosity.

High Electromechanical Response of Ionic Polymer Actuators with Controlled-Morphology Aligned Carbon Nanotube/Nafion Nanocomposite Electrodes

PubMed Central

Liu, Sheng; Liu, Yang; Cebeci, Hülya; de Villoria, Roberto Guzmán; Lin, Jun-Hong

2011-01-01

Recent advances in fabricating controlled-morphology vertically aligned carbon nanotubes (VA-CNTs) with ultrahigh volume fraction create unique opportunities for markedly improving the electromechanical performance of ionic polymer conductor network composite (IPCNC) actuators. Continuous paths through inter-VA-CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast device actuation speed (>10% strain/second). One critical issue in developing advanced actuator materials is how to suppress the strain that does not contribute to the actuation (unwanted strain) thereby reducing actuation efficiency. Here our experiments demonstrate that the VA-CNTs give an anisotropic elastic response in the composite electrodes, which suppresses the unwanted strain and markedly enhances the actuation strain (>8% strain under 4 volts). The results reported here suggest pathways for optimizing the electrode morphology in IPCNCs using ultra-high volume fraction VA-CNTs to further enhanced performance. PMID:21765822

Morphological and molecular characteristics of a new species of Pasteuria parasitic on Meloidogyne ardenensis.

PubMed

Bishop, Alistair H; Gowen, Simon R; Pembroke, Barbara; Trotter, James R

2007-09-01

A species of the hyper-parasitic bacterium Pasteuria was isolated from the root-knot nematode Meloidogyne ardenensis infecting the roots of ash (Fraxinus excelsior). It is morphologically different from some other Pasteuria pathogens of nematodes in that the spores lack a basal ring on the ventral side of the spore and have a unique clumping nature. Transmission electron microscopy (TEM) showed that the clumps of spores are not random aggregates but result from the disintegration of the suicide cells of the thalli. Sporulation within each vegetative mycelium was shown to be asynchronous. In addition to the novel morphological features 16S rRNA sequence analysis showed this to be a new species of Pasteuria which we have called P. hartismeri. Spores of P. hartismeri attach to juveniles of root-knot nematodes infecting a wide range of plants such as mint (Meloidogyne hapla), rye grass (unidentified Meloidogyne sp.) and potato (Meloidogyne fallax).

Morphologies, Processing and Properties of Ceramic Foams from Pre-Ceramic Foams from Pre-Ceramic Polymer Routes

NASA Technical Reports Server (NTRS)

Stackpoole, Mairead; Simoes, Conan R.; Venkatapathy, Ethiras (Technical Monitor)

2002-01-01

The current research is focused on processing ceramic foams that have potential as a thermal protection material. Ceramic foams with different architectures were formed from the pyrolysis of pre-ceramic polymers at 1200 C in different atmospheres. In some systems a sacrificial polyurethane was used as the blowing agent. We have also processed foams using sacrificial fillers to introduce controlled cell sizes. Each sacrificial filler or blowing agent leads to a unique morphology. The effect of different fillers on foam morphologies will be presented. The presentation will also focus on characterization of these foams in terms of mechanical and thermal properties. Foams processed using these approaches having bulk densities ranging from 0.15 to 0.9 g per cubic centimeter and a cell sizes from 5 to 500 micrometers. Compression strengths ranged from 2 to 7 MPa for these materials.

Influence de l'introduction de défauts colonnaires amorphes sur les propriétés de transport d'un monocristal supraconducteur à haute Tc

NASA Astrophysics Data System (ADS)

Warmont, Franck; Hébert, Sylvie; Hardy, Vincent; Martin, Christine; Simon, Charles; Provost, Jackie

1997-12-01

Columnar defects can be introduced in high T_c superconductors by irradiation with high energy heavy ions. The concentration of these artificial pinning centers with a well characterized morphology is easily controlled. The pinning efficiency of these defects has been often demonstrated, mainly from magnetization measurements. In the present work, measurements of the electrical resistance along the c axis, R_c(T), in the presence of columnar defects are presented. They show the ability of these defects to prevent the thermal fluctuations effects. The measurements have been performed on the same crystal before and after the heavy ion irradiation. L'irradiation aux ions lourds de haute énergie permet d'introduire des défauts colonnaires amorphes dans les supraconducteurs à haute T_c. Ces centres de pinning artificiel, de morphologie connue, sont introduits en concentration facile à maîtriser. L'efficacité de ces défauts a été très souvent démontrée à partir de mesures d'aimantation. L'étude présentée ici : mesure de la résistance selon l'axe c, R_c(T), en présence de défauts colonnaires parallèles à l'axe c, montre que ces défauts sont capables de s'opposer efficacement à l'effet des fluctuations thermiques. Les mesures ont été faites sur le même monocristal avant et après l'irradiation.

Tailoring the yield and characteristics of wood cellulose nanocrystals (CNC) using concentrated acid hydrolysis

Treesearch

Liheng Chen; Qianqian Wang; Kolby Hirth; Carlos Baez; Umesh P. Agarwal; J. Y. Zhu

2015-01-01

Cellulose nanocrystals (CNC) have recently received much attention in the global scientific community for their unique mechanical and optical properties. Here, we conducted the first detailed exploration of the basic properties of CNC, such as morphology, crystallinity, degree of sulfation and yield, as a function of production condition variables. The rapid cellulose...

Inverted Martian Craters in Lineated Glacial Valleys, Ismenius Lacus Region, Mars

NASA Technical Reports Server (NTRS)

McConnell, B. S.; Wilt, G. L.; Gillespie, A.; Newsom, H. E.

2005-01-01

We studied small, uniquely-shaped craters found on the surface of lineated terrain in the Ismenius Lacus region of Mars. By utilizing MOC and THEMIS satellite images, we located terrain including lineations (viscous flow features), smoothing of topography, and morphologic features such as polygons and gullies, which appear to be strong evidence of preexisting ice deposits.

Modifications to a LATE MERISTEM IDENTITY-1 gene are responsible for the major leaf shapes of Upland cotton (Gossypium hirsutum L.)

USDA-ARS?s Scientific Manuscript database

Leaf shape varies spectacularly among plants. Leaves are the primary source of photo-assimilate in crop plants and understanding the genetic basis of variation in leaf morphology is critical to improving agricultural productivity. Leaf shape played a unique role in cotton improvement, as breeders ha...

Ultrasmall Peptides Self-Assemble into Diverse Nanostructures: Morphological Evaluation and Potential Implications

PubMed Central

Lakshmanan, Anupama; Hauser, Charlotte A.E.

2011-01-01

In this study, we perform a morphological evaluation of the diverse nanostructures formed by varying concentration and amino acid sequence of a unique class of ultrasmall self-assembling peptides. We modified these peptides by replacing the aliphatic amino acid at the C-aliphatic terminus with different aromatic amino acids. We tracked the effect of introducing aromatic residues on self-assembly and morphology of resulting nanostructures. Whereas aliphatic peptides formed long, helical fibers that entangle into meshes and entrap >99.9% water, the modified peptides contrastingly formed short, straight fibers with a flat morphology. No helical fibers were observed for the modified peptides. For the aliphatic peptides at low concentrations, different supramolecular assemblies such as hollow nanospheres and membrane blebs were found. Since the ultrasmall peptides are made of simple, aliphatic amino acids, considered to have existed in the primordial soup, study of these supramolecular assemblies could be relevant to understanding chemical evolution leading to the origin of life on Earth. In particular, we propose a variety of potential applications in bioengineering and nanotechnology for the diverse self-assembled nanostructures. PMID:22016623

Measuring sickle cell morphology in flow using spectrally encoded flow cytometry (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kviatkovsky, Inna; Zeidan, Adel; Yeheskely-Hayon, Daniella; Dann, Eldad J.; Yelin, Dvir

2017-02-01

During a sickle cell crisis in sickle cell anemia patients, deoxygenated red blood cells may change their mechanical properties and block small blood vessels, causing pain, local tissue damage and even organ failure. Measuring these cellular structural and morphological changes is important for understanding the factors contributing to vessel blockage and developing an effective treatment. In this work, we use spectrally encoded flow cytometry for confocal, high-resolution imaging of flowing blood cells from sickle cell anemia patients. A wide variety of cell morphologies were observed by analyzing the interference patterns resulting from reflections from the front and back faces of the cells' membrane. Using numerical simulation for calculating the two-dimensional reflection pattern from the cells, we propose an analytical expression for the three-dimensional shape of a characteristic sickle cell and compare it to a previous from the literature. In vitro spectrally encoded flow cytometry offers new means for analyzing the morphology of sickle cells in stress-free environment, and could provide an effective tool for studying the unique physiological properties of these cells.

Reflectance confocal microscopy of red blood cells: simulation and experiment (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zeidan, Adel; Yeheskely-Hayon, Daniella; Minai, Limor; Yelin, Dvir

2016-03-01

The properties of red blood cells are a remarkable indicator of the body's physiological condition; their density could indicate anemia or polycythemia, their absorption spectrum correlates with blood oxygenation, and their morphology is highly sensitive to various pathologic states including iron deficiency, ovalocytosis, and sickle cell disease. Therefore, measuring the morphology of red blood cells is important for clinical diagnosis, providing valuable indications on a patient's health. In this work, we simulated the appearance of normal red blood cells under a reflectance confocal microscope and discovered unique relations between the cells' morphological parameters and the resulting characteristic interference patterns. The simulation results showed good agreement with in vitro reflectance confocal images of red blood cells, acquired using spectrally encoded flow cytometry (SEFC) that imaged the cells during linear flow and without artificial staining. By matching the simulated patterns to the SEFC images of the cells, the cells' three-dimensional shapes were evaluated and their volumes were calculated. Potential applications include measurement of the mean corpuscular volume, cell morphological abnormalities, cell stiffness under mechanical stimuli, and the detection of various hematological diseases.

Electron microscopic examination of uncultured soil-dwelling bacteria.

PubMed

Amako, Kazunobu; Takade, Akemi; Taniai, Hiroaki; Yoshida, Shin-ichi

2008-05-01

Bacteria living in soil collected from a rice paddy in Fukuoka, Japan, were examined by electron microscopy using a freeze-substitution fixation method. Most of the observed bacteria could be categorized, based on the structure of the cell envelope and overall morphology, into one of five groups: (i) bacterial spore; (ii) Gram-positive type; (iii) Gram-negative type; (iv) Mycobacterium like; and (v) Archaea like. However, a few of the bacteria could not be readily categorized into one of these groups because they had unique cell wall structures, basically resembling those of Gram-negative bacteria, but with the layer corresponding to the peptidoglycan layer in Gram-negative bacteria being extremely thick, like that of the cortex of a bacterial spore. The characteristic morphological features found in many of these uncultured, soil-dwelling cells were the nucleoid being in a condensed state and the cytoplasm being shrunken. We were able to produce similar morphologies in vitro using a Salmonella sp. by culturing under low-temperature, low-nutrient conditions, similar to those found in some natural environments. These unusual morphologies are therefore hypothesized to be characteristic of bacteria in resting or dormant stages.

Invasive Aspergillus terreus morphological transitions and immunoadaptations mediating antifungal resistance.

PubMed

Bengyella, Louis; Yekwa, Elsie Laban; Subhani, Muhammad Nasir; Tambo, Ernest; Nawaz, Kiran; Hetsa, Bakoena Ashton; Iftikhar, Sehrish; Waikhom, Sayanika Devi; Roy, Pranab

2017-01-01

Aspergillus terreus Thom is a pathogen of public health and agricultural importance for its seamless abilities to expand its ecological niche. The aim of this study was holistically to investigate A. terreus morphological and immunoadaptations and their implication in antifungal resistance and proliferation during infection. In-depth unstructured mining of relevant peer-reviewed literature was performed for A. terreus morphological, immune, resistance, and genetic diversity based on the sequenced calmodulin-like gene. Accessory conidia and phialidic conidia produced by A. terreus confer discrete anti-fungal resistance that ensures survivability during therapies. Interestingly, by producing unique metabolites such as Asp-melanin and terretonin, A. terreus is capable of hijacking macrophages and scavenging iron, respectively. As such, A. terreus has established a rare mechanism to mitigate phagocytosis and swing the interaction dynamics in favor of its proliferation and survival in hosts. It is further unraveled that besides A. terreus genetic diversity, morphological, biochemical, and immunologic adaptations associated with conidia germination and discharge of chemical signals during infection enable masking of the host defense as an integral part of its strategy to survive and rapidly colonize hosts.

The morphology of the inner ear of squamate reptiles and its bearing on the origin of snakes

NASA Astrophysics Data System (ADS)

Palci, Alessandro; Hutchinson, Mark N.; Caldwell, Michael W.; Lee, Michael S. Y.

2017-08-01

The inner ear morphology of 80 snake and lizard species, representative of a range of ecologies, is here analysed and compared to that of the fossil stem snake Dinilysia patagonica, using three-dimensional geometric morphometrics. Inner ear morphology is linked to phylogeny (we find here a strong phylogenetic signal in the data that can complicate ecological correlations), but also correlated with ecology, with Dinilysia resembling certain semi-fossorial forms (Xenopeltis and Cylindrophis), consistent with previous reports. We here also find striking resemblances between Dinilysia and some semi-aquatic snakes, such as Myron (Caenophidia, Homalopsidae). Therefore, the inner ear morphology of Dinilysia is consistent with semi-aquatic as well as semi-fossorial habits: the most similar forms are either semi-fossorial burrowers with a strong affinity to water (Xenopeltis and Cylindrophis) or amphibious, intertidal forms which shelter in burrows (Myron). Notably, Dinilysia does not cluster as closely with snakes with exclusively terrestrial or obligate burrowing habits (e.g. scolecophidians and uropeltids). Moreover, despite the above similarities, Dinilysia also occupies a totally unique morphospace, raising issues with linking it with any particular ecological category.

Phylogeny of Selaginellaceae: There is value in morphology after all!

PubMed

Weststrand, Stina; Korall, Petra

2016-12-01

The cosmopolitan lycophyte family Selaginellaceae, dating back to the Late Devonian-Early Carboniferous, is notorious for its many species with a seemingly undifferentiated gross morphology. This morphological stasis has for a long time hampered our understanding of the evolutionary history of the single genus Selaginella. Here we present a large-scale phylogenetic analysis of Selaginella, and based on the resulting phylogeny, we discuss morphological evolution in the group. We sampled about one-third of the approximately 750 recognized Selaginella species. Evolutionary relationships were inferred from both chloroplast (rbcL) and single-copy nuclear gene data (pgiC and SQD1) using a Bayesian inference approach. The morphology of the group was studied and important features mapped onto the phylogeny. We present an overall well-supported phylogeny of Selaginella, and the phylogenetic positions of some previously problematic taxa (i.e., S. sinensis and allies) are now resolved with strong support. We show that even though the evolution of most morphological characters involves reversals and/or parallelisms, several characters are phylogenetically informative. Seven major clades are identified, which each can be uniquely diagnosed by a suite of morphological features. There is value in morphology after all! Our hypothesis of the evolutionary relationships of Selaginella is well founded based on DNA sequence data, as well as morphology, and is in line with previous findings. It will serve as a firm basis for further studies on Selaginella with respect to, e.g., the poorly known alpha taxonomy, as well as evolutionary questions such as historical biogeographic reconstructions. © 2016 Weststrand and Korall. Published by the Botanical Society of America. This work is licensed under a Creative Commons Attribution License (CC-BY 4.0).

Fasciola hepatica: Histology of the Reproductive Organs and Differential Effects of Triclabendazole on Drug-Sensitive and Drug-Resistant Fluke Isolates and on Flukes from Selected Field Cases.

PubMed

Hanna, Robert

2015-06-26

This review summarises the findings of a series of studies in which the histological changes, induced in the reproductive system of Fasciola hepatica following treatment of the ovine host with the anthelmintic triclabendazole (TCBZ), were examined. A detailed description of the normal macroscopic arrangement and histological features of the testes, ovary, vitelline tissue, Mehlis' gland and uterus is provided to aid recognition of the drug-induced lesions, and to provide a basic model to inform similar toxicological studies on F. hepatica in the future. The production of spermatozoa and egg components represents the main energy consuming activity of the adult fluke. Thus the reproductive organs, with their high turnover of cells and secretory products, are uniquely sensitive to metabolic inhibition and sub-cellular disorganisation induced by extraneous toxic compounds. The flukes chosen for study were derived from TCBZ-sensitive (TCBZ-S) and TCBZ-resistant (TCBZ-R) isolates, the status of which had previously been proven in controlled clinical trials. For comparison, flukes collected from flocks where TCBZ resistance had been diagnosed by coprological methods, and from a dairy farm with no history of TCBZ use, were also examined. The macroscopic arrangement of the reproductive system in flukes was studied using catechol/carmine stained whole mounts, and the histology of the main organs was examined using conventional haematoxylin-eosin stained sections. Validation of apoptosis in the fluke sections was carried out using an in situ hybridisation method designed to label endonuclease-induced DNA strand breaks. In TCBZ-S flukes exposed to TCBZ metabolites for 24-96 h in vivo, but not in TCBZ-R flukes, those tissues where active meiosis and/or mitosis occurred (testis, ovary, and vitelline follicles), were found to display progressive loss of cell content. This was due to apparent failure of cell division to keep pace with expulsion of the mature or effete products. Further, actively dividing cell types tended to become individualised, rounded and condensed, characteristic of apoptotic cell death. In the treated TCBZ-S flukes, strong positive labelling indicating apoptosis was associated with the morphologically abnormal cells undergoing mitosis or meiosis in the testis, ovary and vitelline follicles. In treated flukes from field outbreaks of suspected TCBZ-R fasciolosis, no significant histological changes were observed, nor was there any positive labelling for apotosis. On the other hand, sections of TCBZ treated flukes derived from a field case of fasciolosis where TCBZ resistance was not suspected displayed severe histological lesions, and heavy positive labelling for apoptosis. The triggering of apoptosis is considered to be related to failure of spindle formation at cell division, supporting the contention that TCBZ inhibits microtubule formation. In treated TCBZ-S flukes, protein synthesis and transport was apparently inhibited in the Mehlis' secretory cells, perhaps due to energy uncoupling or to microtubule defects. In the uterus, successful formation of shelled eggs represents the culmination of a complex sequence of cytokinetic, cytological and synthetic activity involving the vitelline follicles, the ovary and the Mehlis' gland. Histological evidence indicating failure of ovigenesis in TCBZ-S flukes was evident from as early as 24 h post-treatment onwards. Light labelling for apoptosis was associated with the testis of untreated Cullompton (TCBZ-S) and Sligo type 2 (TCBZ-R) flukes, which exhibit abnormal spermatogenesis and spermiogenesis, respectively. This was attributed to apoptosis and to heterophagy of effete germ line cells by the sustentacular tissue. The studies summarised in this review illustrate the potential utility of histological techniques for conveniently screening representative samples of flukes in field trials designed to validate instances of drug resistance. Histology can also be used to test the efficacy of new products against known drug-resistant and drug-susceptible fluke isolates. The account also provides reference criteria for drug-induced histopathological changes in fluke reproductive structures, examination of which may supplement and augment conventional coprological testing, and aid interpretation of TEM findings.

The Impact of Morphological Awareness on Word Reading and Dictation in Chinese Early Adolescent Readers With and Without Dyslexia.

PubMed

Kalindi, Sylvia Chanda; Chung, Kevin Kien Hoa

2018-01-01

This study investigated the role of morphological awareness in understanding Chinese word reading and dictation among Chinese-speaking adolescent readers in Hong Kong as well as the cognitive-linguistic profile of early adolescent readers with dyslexia. Fifty-four readers with dyslexia in Grades 5 and 6 were compared with 54 chronological age-matched (CA) typical readers on the following measures of cognitive-linguistic and literacy skills: morphological awareness, phonological awareness, visual-orthographic knowledge, rapid naming, vocabulary knowledge, verbal short-term memory (STM), Chinese word reading, and dictation (or spelling). The results indicated that early adolescent readers with dyslexia performed less well than the typical readers on all cognitive-linguistic and literacy measures except the phonological measures. Both groups' scores showed substantial correlations between morphological awareness and Chinese word reading and dictation. Visual-orthographic knowledge and rapid naming were also associated with dictation in early adolescent readers with and without dyslexia, respectively. Moderated multiple regression analyses further revealed that morphological awareness and rapid naming explained unique variance in word reading and dictation for the readers with dyslexia and typical readers separately after controlling readers' age and group effect. These results highlight the potential importance of morphological awareness and rapid naming in Chinese word reading and writing in Chinese early adolescents' literacy development and impairment.

Cranial base morphology and temporal bone pneumatization in Asian Homo erectus.

PubMed

Balzeau, Antoine; Grimaud-Hervé, Dominique

2006-10-01

The external morphological features of the temporal bone are used frequently to determine taxonomic affinities of fossils of the genus Homo. Temporal bone pneumatization has been widely studied in great apes and in early hominids. However, this feature is rarely examined in the later hominids, particularly in Asian Homo erectus. We provide a comparative morphological and quantitative analysis of Asian Homo erectus from the sites of Ngandong, Sambungmacan, and Zhoukoudian, and of Neandertals and anatomically modern Homo sapiens in order to discuss causes and modalities of temporal bone pneumatization during hominid evolution. The evolution of temporal bone pneumatization in the genus Homo is more complex than previously described. Indeed, the Zhoukoudian fossils have a unique pattern of temporal bone pneumatization, whereas Ngandong and Sambungmacan fossils, as well as the Neandertals, more closely resemble the modern human pattern. Moreover, these Chinese fossils are characterized by a wide midvault and a relatively narrow occipital bone. Our results support the point of view that cell development does not play an active role in determining cranial base morphology. Instead, pneumatization is related to available space and to temporal bone morphology, and its development is related to correlated morphology and the relative disposition of the bones and cerebral lobes. Because variation in pneumatization is extensive within the same species, the phyletic implications of pneumatization are limited in the taxa considered here.

Real-Time X-Ray Microscopy of Al-Cu Eutectic Solidification

NASA Technical Reports Server (NTRS)

Kaukler, William F.; Curreri, Peter A.; Sen, Subhayu

1998-01-01

Recent improvements in the resolution of the X-ray Transmission Microscope (XTM) for Solidification Studies provide microstructure feature detectability down to 5 micrometers during solidification. This presentation will show the recent results from observations made in real-time of the solid-liquid interfacial morphologies of the Al-CuAI2 eutectic alloy. Lamellar dimensions and spacings, transitions of morphology caused by growth rate changes, and eutectic grain structures are open to measurements. A unique vantage point viewing the face of the interface isotherm is possible for the first time with the XTM due to its infinite depth of field. A video of the solid-liquid interfaces seen in-situ and in real-time will be shown.

Egg morphology, laying behavior and record of the host plants of Ricania speculum (Walker, 1851), a new alien species for Europe (Hemiptera: Ricaniidae).

PubMed

Rossi, Elisabetta; Stroiński, Adam; Lucchi, Andrea

2015-11-17

The exotic planthopper, Ricania speculum (Ricaniidae) was recently detected in Liguria, in northern Italy, and recorded as a first alert for Europe. The first morphological description of eggs and laying behavior are given. Eggs are inserted into the woody tissue of a wide range of different host plants in such a unique manner among native and alien planthoppers of Italy that it can be used to describe the prevalence and diffusion of the species in new environments, though in the absence of juveniles and/or adults. In addition, the paper lists the host plants utilized for egg laying and describes the eggs.

Preparation and magnetic properties of magnetic photonic crystal by using monodisperse polystyrene covered Fe3O4 nanoparticles onto glass substrate

NASA Astrophysics Data System (ADS)

Azizi, Zahra Sadat; Tehranchi, Mohammad Mehdi; Vakili, Seyed Hamed; Pourmahdian, Saeed

2018-05-01

Engineering approach towards combined photonic band gap properties and magnetic/polymer composite particles, attract considerable attention of researchers due to their unique properties. In this research, two different magnetic particles were prepared by nearly monodisperse polystyrene spheres as bead with two concentrations of Fe3O4 nanoparticles to prepare magnetic photonic crystals (MPCs). The crystal surfaces and particles morphology were investigated employing scanning electron microscopy and transmission electron microscopy. The volume fraction of magnetic material embedded into colloidal spheres and their morphology was found to be a key parameter in the optical and magneto-optical properties of transparent MPC.

Preparation and morphology, magnetic properties of yttrium iron garnet nanodot arrays on Gd3Ga5O12 substrate

NASA Astrophysics Data System (ADS)

Xu, Zhiwang; Zheng, Hui; Han, Mangui

2017-07-01

In this work, yttrium iron garnet nanodot array has been deposited on Gd3Ga5O12 substrate by pulsed laser deposition through an ultrathin alumina mask. The morphology and magnetic properties of YIG nanodot array have been investigated. Scanning electron microscopy displays the prepared nanodot array has a sharp distribution in diameter centered at 330 nm with standard deviation of 20 nm. X-ray diffraction θ-2θ and pole figure analysis show the yttrium iron garnet nanodot array has oriented growth. Moreover, typical hysteresis loops and ferromagnetic resonance spectra display larger coercivity and multi-resonance peaks which are ascribed to this unique structure.

Morphological characterization of Eustrongylides sp. larvae (Nematoda, Dioctophymatoidea) parasite of Rhinella marina (Amphibia: Bufonidae) from Eastern Amazonia.

PubMed

Melo, Francisco Tiago de Vasconcelos; Melo, Caroline do Socorro Barros; Nascimento, Luciana de Cássia Silva do; Giese, Elane Guerreiro; Furtado, Adriano Penha; Santos, Jeannie Nascimento Dos

2016-06-07

Absctract Eustrongylides spp. nematodes have birds as final hosts and uses other vertebrates as intermediate/paratenic host (fish, amphibians and reptiles) and have zoonotic potential. In amphibians, the larvae may be located in the subcutaneous tissues, liver and mesentery, between the muscle fibres, especially in the lower limbs. Rhinella marina, which is widely observed in Brazil, has exhibited complex diversity in its helminth fauna, reflecting the unique habitat of the Amazon biome. For the first time, this study describes the morphological aspects of third-stage larvae of Eustrongylides sp. in Rhinella marina from Santa Cruz do Ararí, Marajó Archipelago, Eastern Amazonia, using light and scanning electron microscopy.

Malformations congénitales à Lubumbashi (République Démocratique du Congo): à propos de 72 cas observés et plaidoyer en faveur du développement d'un Registre National des Malformations Congénitales et d'un Centre National de Référence de Génétique Humaine

PubMed Central

Lubala, Toni Kasole; Shongo, Mick Yapongombo; Munkana, Arthur Ndundula; Mutombo, Augustin Mulangu; Mbuyi, Sébastien Musanzayi; wa Momat, Félix Kitenge

2012-01-01

En République Démocratique du Congo, les malformations congénitales constituent un véritable problème de santé publique. En effet, elles relancent le débat sur les effets de l'intensification de l'activité minière sur la santé de la reproduction. De 2009 à 2010, nous avons calculé une prévalence de 5.84 pour 1000 naissances. Les malformations du système nerveux central étaient les plus fréquentes (2.029 pour 1000) suivies des malformations des membres (1.055 pour 1000), et des fentes oro-faciales (0.811 pour 1000). Ces données sont certainement largement sous-estimées et les causes y relatives en République Démocratique du Congo ne sont ni surveillées, ni prévenues dans le cadre d'une politique gouvernementale. La mise en place d'un registre national et d'un centre national de génétique humaine de référence pourrait constituer un cadre rigoureux, organisé et structuré de surveillance et de prévention des malformations congénitales. PMID:23396951

Cold pearl surfactant-based blends.

PubMed

Crombie, R L

1997-10-01

Pearlizing agents have been used for many years in cosmetic formulations to add a pearlescent effect. Cold pearl surfactant-based blends are mixtures of glycol stearates and surfactants which can be blended in the cold into a wide range of personal-care formulations to create a pearlescent lustre effect. Under controlled manufacturing conditions constant viscosities and crystalline characteristics can be obtained. The development of these blends has been driven by efforts to improve the economics of adding solid pearlizing agents directly into a hot mix formulation. This paper summarizes the history of pearlizers, describes their advantages and physical chemistry of the manufacturing process. Finally some suggestions for applications are given. Les agents nacrants sont utilises depuis de nombreuses annees dans les formulations cosmetiques pour ajouter un effet nacre. Les melanges a froid a base de tensioactif nacre sont des melanges de stearates de glycol et de tensioactifs qui peuvent etre melanges a froid dans une large gamme de formulations d'hygiene personnelle pour creer un effet de lustre nacre. On peut obtenir des viscosites et des proprietes cristallines constantes avec des conditions de fabrication maitrisees. Le developpement de ces melanges a ete porte par les efforts pour ameliorer les couts de l'ajout d'agents nacrants solides directement dans une formulation melangee de l'ajout d'agents nacrants solides directement dans une formulation melangee a chaud. Cet article resume l'histoire des agents nacrants, decrit leurs avantages et al physico-chimie du procede de fabrication. On emet a la fin cetaines suggestions d'applications.

Influence des traitements thermiques et de la microstructure sur les phénomènes de découplage dans les composés au bismuth

NASA Astrophysics Data System (ADS)

Nicolas, M.; Guyen van Huong, C. N.; Burger, J. P.; Dubon, A.; Fitoussi, J. P.; Laval, J. Y.

1991-11-01

a.c. susceptibility measurements and 3D electronic microscopy observation were carried out on three Bi-compounds (2212 and 2223). Depending on the annealing conditions, one observes lamellar-type materials organized either in a more or less dense structure of fine particles or in very large slabs. The a.c. susceptibility signals allow to separate the intergranular from the intragranular effects. The combined results obtained by both techniques lead us to conclude that the intergranular and the intragranular decoupling, induced by magnetic fields are of same nature, i.e. occur at the (BiO)2 slab. Nous avons couplé des mesures de susceptibilité altemative et d'observation au microscope électronique en 3D sur trois échantillons supraconducteurs au bismuth (2212 et 2223). Selon les conditions de recuit, on observe des matériaux de type lamellaire, organisés soit en une structure plus ou moins dense de fines particules, soit en larges plaquettes. L'étude des signaux de susceptibilité alternative χ' et χ'' permet de séparer les effets intergranulaires des effets intragranulaires. les résultats combinés des deux techniques nous ont conduit à conclure que les deux types de découplage (inter et intragranulaires), induits par les champs magnétiques sont de même nature, c'est-à-dire se produisent au niveau des bicouches (BiO)2.

Magnétochiralité et résonances stochastiques dans les lasers

NASA Astrophysics Data System (ADS)

Bonnet, C.; Bretenaker, F.; Brunel, M.; Chauvat, D.; Emile, O.; Lai, N. D.; Le Floch, A.; Ropars, G.; Ruchon, T.; Singh, K.; Thépot, J.-Y.; Vallet, M.

2002-06-01

Les états propres d'un laser constituent un outil de choix pour étudier les différents rôles joués par le bruit dans un système. D'une part, si on veut isoler un effet petit difficilement accessible par les méthodes classiques, ces états propres permettent de réaliser des mesures différentielles de haute précision, à condition de pouvoir éliminer les bruits mécaniques, optiques, électroniques. A titre d'exemple, nous avons utilisé les états propageant et contrapropageant d'un laser ionique en anneau pour mesurer une interaction fondamentale faible: la biréfringence magnétochirale. Cette "biréfringence" se manifeste en effet par une petite variation d'indice selon le sens de parcours de l'anneau, de l'ordre de Δ n.10^{-11}, indépendante de la polarisation. A l'opposé, les deux états propres d'un laser du type Fabry-Perot constituent un système idéal pour explorer les résonances stochastiques à deux dimensions. Les résonances stochastiques par inhibition et par rotation sont isolées en présence de bruits blancs gaussiens tant pour les bruits optiques que magnétiques. L'utilisation possible de l'émission spontanée comme bruit actif est démontrée.

Morphology supporting function: attenuation correction for SPECT/CT, PET/CT, and PET/MR imaging

PubMed Central

Lee, Tzu C.; Alessio, Adam M.; Miyaoka, Robert M.; Kinahan, Paul E.

2017-01-01

Both SPECT, and in particular PET, are unique in medical imaging for their high sensitivity and direct link to a physical quantity, i.e. radiotracer concentration. This gives PET and SPECT imaging unique capabilities for accurately monitoring disease activity for the purposes of clinical management or therapy development. However, to achieve a direct quantitative connection between the underlying radiotracer concentration and the reconstructed image values several confounding physical effects have to be estimated, notably photon attenuation and scatter. With the advent of dual-modality SPECT/CT, PET/CT, and PET/MR scanners, the complementary CT or MR image data can enable these corrections, although there are unique challenges for each combination. This review covers the basic physics underlying photon attenuation and scatter and summarizes technical considerations for multimodal imaging with regard to PET and SPECT quantification and methods to address the challenges for each multimodal combination. PMID:26576737

The effects of surfactant on the structure of ZnCr2O4 dendrimer like nanostructures used in degradation of Eriochrome Black T

NASA Astrophysics Data System (ADS)

Sabet, Mohammad; Jahangiri, Hasan

2018-01-01

In this experimental work, we synthesized ZnCr2O4 nano dendrimer-like structures via a simple hydrothermal method. Different parameters such as the reaction time and temperature and the surfactant kind were changed to obtain different particle sizes and morphologies. Scanning electron microscopy was utilized to obtain the products morphologies. The results showed the product is mainly composed of dendrimer-like structures. Also, it was found the mentioned parameters had significant effects on the product sizes and morphologies. Furthermore, it was found key parameters that determine the morphology of the product is surfactant type and each surfactant creates a unique morphology. The crystallinity and crystallite size were studied by x-ray diffraction pattern. Also, the composition of the product was determined by energy dispersive x-ray analysis. Diffuse reflectance spectroscopy (DRS) was used to the investigation of the optical properties of the product. The results obtained from DRS spectra showed the product has about 3.3 eV band gap. The photocatalytic activity of the product showed that ZnCr2O4 has a significant photocatalytic activity and it can decompose Eriochrome Black T about 91% under ultra violet radiation.

Morphology control of rutile TiO2 with tunable bandgap by preformed β-FeOOH nanoparticles.

PubMed

Chen, Zheming; Wang, Feng; Balachandran, Subramanian; Li, Gen; Liu, Peng; Ding, Yanfen; Zhang, Shimin; Yang, Mingshu

2018-03-23

Rutile TiO 2 are widely used for applications of coatings, cosmetics, photoelectric devices and so on. However, effective control of well-defined morphology, size and composition of rutile TiO 2 nanoparticles from agglomeration has always been a challenge. A new synthesis strategy was proposed to prepare rutile TiO 2 with controllable morphology varied from flower-like structures to single-separated nanorods. The β-FeOOH nanoparticles were generated by the hydrolysis of FeCl 3 solution and could prevent the aggregation of TiO 2 nanocrystals at early stages of the reaction; thus, could control the morphology of rutile nanoparticles. The morphology of rutile TiO 2 nanoparticles could be controllably regulated from flower-like structures to individually separated nanorods. Meanwhile, the preformed β-FeOOH also played a role of dopant. Fe ions were substitutionally doped into the bulk lattice of TiO 2 nanocrystals and reduced the bandgap, which extended the solar radiation absorption range of rutile TiO 2 . The prepared TiO 2 may be suitable for novel UV-blue light shielding agents and many other applications in photoelectric devices, photocatalysis, and so on due to its small size, unprecedented discrete rod-like structure and unique UV-vis light permeability.

Morphology control of rutile TiO2 with tunable bandgap by preformed β-FeOOH nanoparticles

NASA Astrophysics Data System (ADS)

Chen, Zheming; Wang, Feng; Balachandran, Subramanian; Li, Gen; Liu, Peng; Ding, Yanfen; Zhang, Shimin; Yang, Mingshu

2018-03-01

Rutile TiO2 are widely used for applications of coatings, cosmetics, photoelectric devices and so on. However, effective control of well-defined morphology, size and composition of rutile TiO2 nanoparticles from agglomeration has always been a challenge. A new synthesis strategy was proposed to prepare rutile TiO2 with controllable morphology varied from flower-like structures to single-separated nanorods. The β-FeOOH nanoparticles were generated by the hydrolysis of FeCl3 solution and could prevent the aggregation of TiO2 nanocrystals at early stages of the reaction; thus, could control the morphology of rutile nanoparticles. The morphology of rutile TiO2 nanoparticles could be controllably regulated from flower-like structures to individually separated nanorods. Meanwhile, the preformed β-FeOOH also played a role of dopant. Fe ions were substitutionally doped into the bulk lattice of TiO2 nanocrystals and reduced the bandgap, which extended the solar radiation absorption range of rutile TiO2. The prepared TiO2 may be suitable for novel UV-blue light shielding agents and many other applications in photoelectric devices, photocatalysis, and so on due to its small size, unprecedented discrete rod-like structure and unique UV-vis light permeability.

Three-dimensional block copolymer nanostructures by the solvent-annealing-induced wetting in anodic aluminum oxide templates.

PubMed

Chu, Chiang-Jui; Chung, Pei-Yun; Chi, Mu-Huan; Kao, Yi-Huei; Chen, Jiun-Tai

2014-09-01

Block copolymers have been extensively studied over the last few decades because they can self-assemble into well-ordered nanoscale structures. The morphologies of block copolymers in confined geometries, however, are still not fully understood. In this work, the fabrication and morphologies of three-dimensional polystyrene-block-polydimethylsiloxane (PS-b-PDMS) nanostructures confined in the nanopores of anodic aluminum oxide (AAO) templates are studied. It is discovered that the block copolymers can wet the nanopores using a novel solvent-annealing-induced nanowetting in templates (SAINT) method. The unique advantage of this method is that the problem of thermal degradation can be avoided. In addition, the morphologies of PS-b-PDMS nanostructures can be controlled by changing the wetting conditions. Different solvents are used as the annealing solvent, including toluene, hexane, and a co-solvent of toluene and hexane. When the block copolymer wets the nanopores in toluene vapors, a perpendicular morphology is observed. When the block copolymer wets the nanopores in co-solvent vapors (toluene/hexane = 3:2), unusual circular and helical morphologies are obtained. These three-dimensional nanostructures can serve as naontemplates for refilling with other functional materials, such as Au, Ag, ZnO, and TiO2 . © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Repeated Origin and Loss of Adhesive Toepads in Geckos

PubMed Central

Gamble, Tony; Greenbaum, Eli; Jackman, Todd R.; Russell, Anthony P.; Bauer, Aaron M.

2012-01-01

Geckos are well known for their extraordinary clinging abilities and many species easily scale vertical or even inverted surfaces. This ability is enabled by a complex digital adhesive mechanism (adhesive toepads) that employs van der Waals based adhesion, augmented by frictional forces. Numerous morphological traits and behaviors have evolved to facilitate deployment of the adhesive mechanism, maximize adhesive force and enable release from the substrate. The complex digital morphologies that result allow geckos to interact with their environment in a novel fashion quite differently from most other lizards. Details of toepad morphology suggest multiple gains and losses of the adhesive mechanism, but lack of a comprehensive phylogeny has hindered efforts to determine how frequently adhesive toepads have been gained and lost. Here we present a multigene phylogeny of geckos, including 107 of 118 recognized genera, and determine that adhesive toepads have been gained and lost multiple times, and remarkably, with approximately equal frequency. The most likely hypothesis suggests that adhesive toepads evolved 11 times and were lost nine times. The overall external morphology of the toepad is strikingly similar in many lineages in which it is independently derived, but lineage-specific differences are evident, particularly regarding internal anatomy, with unique morphological patterns defining each independent derivation. PMID:22761794

Cochlear Hair Cell Electrochemistry: Mechanisms for Bidirectional Transduction.

DTIC Science & Technology

1988-06-30

cytoplasm in the cell’s laminated cisternal system. More specifically, we postulate that intracochlear potential gradients associated with acoustic...transduction drive intracellular fluids through an electo-osmotic "pump" formed by the plasma membrane and the morphologically unique laminated cisternal ...laminated cisternal system in the hearing loss measured with brainstem evoked response. The highly polycationic nature of the polyamines suggest their

How Simple Is Reading in Arabic? A Cross-Sectional Investigation of Reading Comprehension from First to Sixth Grade

ERIC Educational Resources Information Center

Asadi, Ibrahim A.; Khateb, Asaid; Shany, Michal

2017-01-01

This study aimed to examine, from a cross-sectional perspective, the extent to which the simple view of reading (SVR) model can be adapted to the Arabic language. This was carried out by verifying, in both beginning and more skilled readers, whether the unique orthographical and morphological characteristics of Arabic contribute to reading…

The Role of Argument Structure in Me'phaa Verbal Agreement

ERIC Educational Resources Information Center

Duncan, Philip T.

2017-01-01

This dissertation explores aspects of Me'phaa morphosyntax, from verb roots to verb-initial word orders. I argue that patterns of agreement map directly onto the syntax of argument structure, which in turn feed the language's unique manifestation of ergativity. Me'phaa agreement morphology is richly complex, and I show that this is due, in part,…

Gold nanoprobes for theranostics

PubMed Central

Panchapakesan, Balaji; Book-Newell, Brittany; Sethu, Palaniappan; Rao, Madhusudhana; Irudayaraj, Joseph

2011-01-01

Gold nanoprobes have become attractive diagnostic and therapeutic agents in medicine and life sciences research owing to their reproducible synthesis with atomic level precision, unique physical and chemical properties, versatility of their morphologies, flexibility in functionalization, ease of targeting, efficiency in drug delivery and opportunities for multimodal therapy. This review highlights some of the recent advances and the potential for gold nanoprobes in theranostics. PMID:22122586

Sleep: Helicon Cells Charge the Circuit.

PubMed

Yurgel, Maria E; Keene, Alex C

2018-04-02

A new study in the fruit fly, Drosophila melanogaster, has identified a neural circuitry that connects regions that control sleep with those that encode sleep pressure. These novel cells, termed helicon cells for their unique morphology, are modulated by sleep control centers and integrate sensory information, providing a novel mechanism for gating of sleep. Copyright © 2018 Elsevier Ltd. All rights reserved.

Continuous flow chemical vapour deposition of carbon nanotube sea urchins.

PubMed

de La Verpilliere, Jean; Jessl, Sarah; Saeed, Khuzaimah; Ducati, Caterina; De Volder, Michael; Boies, Adam

2018-04-26

Hybrid structures consisting of functional materials enhanced by carbon nanotubes (CNTs) have potential for a variety of high impact applications, as shown by the impressive progress in sensing and mechanical applications enabled by CNT-enhanced materials. The hierarchical organisation of CNTs with other materials is key to the design of macroscale devices benefiting from the unique properties of individual CNTs, provided CNT density, morphology and binding with other materials are optimized. In this paper, we provide an analysis of a continuous aerosol process to create a hybrid hierarchical sea urchin structure with CNTs organized around a functional metal oxide core. We propose a new mechanism for the growth of these carbon nanotube sea urchins (CNTSU) and give new insight into their chemical composition. To corroborate the new mechanism, we examine the influence of CNT growth conditions on CNTSU morphology and demonstrate a new in-line characterisation technique to continuously monitor aerosol CNT growth during synthesis, which enables industrial-scale production optimization. Based upon the new formation mechanism we describe the first substrate-based chemical vapour deposition growth of CNTSUs which increases CNT length and improves G to D ratio, which also allows for the formation of CNTSU carpets with unique structures.

Highly Oriented Graphene Sponge Electrode for Ultra High Energy Density Lithium Ion Hybrid Capacitors.

PubMed

Ahn, Wook; Lee, Dong Un; Li, Ge; Feng, Kun; Wang, Xiaolei; Yu, Aiping; Lui, Gregory; Chen, Zhongwei

2016-09-28

Highly oriented rGO sponge (HOG) can be easily synthesized as an effective anode for application in high-capacity lithium ion hybrid capacitors. X-ray diffraction and morphological analyses show that successfully exfoliated rGO sponge on average consists of 4.2 graphene sheets, maintaining its three-dimensional structure with highly oriented morphology even after the thermal reduction procedure. Lithium-ion hybrid capacitors (LIC) are fabricated in this study based on a unique cell configuration which completely eliminates the predoping process of lithium ions. The full-cell LIC consisting of AC/HOG-Li configuration has resulted in remarkably high energy densities of 231.7 and 131.9 Wh kg(-1) obtained at 57 W kg(-1) and 2.8 kW kg(-1). This excellent performance is attributed to the lithium ion diffusivity related to the intercalation reaction of AC/HOG-Li which is 3.6 times higher that of AC/CG-Li. This unique cell design and configuration of LIC presented in this study using HOG as an effective anode is an unprecedented example of performance enhancement and improved energy density of LIC through successful increase in cell operation voltage window.

Uniquely confining Cu2S nanoparticles in graphitized carbon fibers for enhanced oxygen evolution reaction

NASA Astrophysics Data System (ADS)

Zhao, Xiaoqian; Liu, Li; Zhang, Yan; Zhang, Huijuan; Wang, Yu

2017-08-01

Up to now, the literature on Cu2S with specific morphology applied to oxygen evolution reaction (OER) in the electrocatalytic field has been limited. In this work, unique peapod-like Cu2S/C exhibiting superb electrocatalytic performance toward OER is successfully synthesized, by employing Cu(OH)2 nanorods as the template and nontoxic glucose as the carbon source and then annealing with sublimed sulfur. It can be seen that this work explores a new application area for Cu2S. More precisely, the novel morphology contributes to increasing the electrochemical active surface area effectively and promoting contact between the Cu2S nanoparticles and the electrolyte. During electrochemical measurements, the peapod-like Cu2S/C shows enhanced electrocatalytic activity with a low overpotential of 401 mV at the current density of 10 mA cm-2 and a Tafel slope of 52 mV dec-1. More importantly, our material is able to maintain stability for at least 8 h at constant potential and the current loss is negligible after 2000 cycles. Obviously, these striking properties fully demonstrate that the peapod-like Cu2S/C as an efficient catalyst shows great promise for OER.

Identification of potential hydrophobic properties of carbon layer from the coffee bean waste

NASA Astrophysics Data System (ADS)

Fitria, D.; Baroroh, L. A. Al; Destyorini, F.; Widayatno, W. B.; Amal, M. I.; Wismogroho, A. S.

2018-03-01

The significant increase of waste due to vast development of human civilization and industrialization has plunged humanity into various environmental issues. Nowadays, the concern on waste handling and conversion into more valuable material has become one of hot research topics. Biomass waste has great abundance with various types that can be utilized for many applications such as landfill, recycled-material, adsorbent, separation, catalysis, and so on. In this study, coffee bean waste (CBW) was used as a source to produce hydrophobic layer. The CBW was converted into amorphous carbon using simple carbonization method at 500 °C, dispersed in acetic acid and then mixed with polyvinyl alcohol (PVA) at low temperature heating. In order to investigate effects of composition on hydrophobicity properties, ratio of carbon and PVA was varied. In addition, acetic acid was used to evaluate effect of dispersant on hydrophobic properties. SEM analysis reveals unique morphology of carbon layer. The measurement of contact angle demonstrates that this unique morphology possesses comparable hydrophobicity with that of some well-known materials. Fourier transform infrared spectroscopy (FTIR) analysis confirms the effect of PVA bonding and carbon layer on its hydrophobicity.

Biomimetic surface structuring using cylindrical vector femtosecond laser beams

NASA Astrophysics Data System (ADS)

Skoulas, Evangelos; Manousaki, Alexandra; Fotakis, Costas; Stratakis, Emmanuel

2017-03-01

We report on a new, single-step and scalable method to fabricate highly ordered, multi-directional and complex surface structures that mimic the unique morphological features of certain species found in nature. Biomimetic surface structuring was realized by exploiting the unique and versatile angular profile and the electric field symmetry of cylindrical vector (CV) femtosecond (fs) laser beams. It is shown that, highly controllable, periodic structures exhibiting sizes at nano-, micro- and dual- micro/nano scales can be directly written on Ni upon line and large area scanning with radial and azimuthal polarization beams. Depending on the irradiation conditions, new complex multi-directional nanostructures, inspired by the Shark’s skin morphology, as well as superhydrophobic dual-scale structures mimicking the Lotus’ leaf water repellent properties can be attained. It is concluded that the versatility and features variations of structures formed is by far superior to those obtained via laser processing with linearly polarized beams. More important, by exploiting the capabilities offered by fs CV fields, the present technique can be further extended to fabricate even more complex and unconventional structures. We believe that our approach provides a new concept in laser materials processing, which can be further exploited for expanding the breadth and novelty of applications.

Hybrid nanostructures of metal/two-dimensional nanomaterials for plasmon-enhanced applications.

PubMed

Li, Xuanhua; Zhu, Jinmeng; Wei, Bingqing

2016-06-07

Hybrid nanostructures composed of graphene or other two-dimensional (2D) nanomaterials and plasmonic metal components have been extensively studied. The unusual properties of 2D materials are associated with their atomically thin thickness and 2D morphology, and many impressive structures enable the metal nanomaterials to establish various interesting hybrid nanostructures with outstanding plasmonic properties. In addition, the hybrid nanostructures display unique optical characteristics that are derived from the close conjunction of plasmonic optical effects and the unique physicochemical properties of 2D materials. More importantly, the hybrid nanostructures show several plasmonic electrical effects including an improved photogeneration rate, efficient carrier transfer, and a plasmon-induced "hot carrier", playing a significant role in enhancing device performance. They have been widely studied for plasmon-enhanced optical signals, photocatalysis, photodetectors (PDs), and solar cells. In this review, the developments in the field of metal/2D hybrid nanostructures are comprehensively described. Preparation of hybrid nanostructures is first presented according to the 2D material type, as well as the metal nanomaterial morphology. The plasmonic properties and the enabled applications of the hybrid nanostructures are then described. Lastly, possible future research in this promising field is discussed.

Les fluctuations supraconductrices dans le compose praseodyme-cerium-oxyde de cuivre

NASA Astrophysics Data System (ADS)

Renaud, Jacques

Ce travail etudie les fluctuations supraconductrices dans le compose supraconducteur a haute temperature critique dope aux electrons Pr2-xCe xCuO4+delta. La technique utilisee pour sonder ces fluctuations est le transport electrique DC dans le plan ab. Il s'agit, a notre connaissance, de la premiere etude de ce type dans la classe generale des supraconducteurs a haute temperature critique dopes aux electrons et, plus particulierement, dans Pr2-xCe xCuO4+delta. De plus, l'etude est effectuee pour trois regimes de dopage, soit sous-dope x = 0.135, dopage optimal x = 0.15 et surdope x = 0.17. Les echantillons etudies sont des couches minces d'epaisseur plus grande que 100 nm crues par ablation laser. Les mesures electriques DC effectuees dans ce travail sont la resistance en reponse lineaire et les courbes IV en reponse non lineaire en fonction de la temperature. La mise en oeuvre experimentale de ces mesures a necessite une grande attention au filtrage et aux effets de chauffage a haut courant. Nous montrons que, sans cette attention, les donnees experimentales sont toujours erronees dans le regime pertinent pour nos echantillons. Les resultats pour le dopage optimal x = 0.15 sont expliques de facon tres convaincante dans le cadre de fluctuations purement 2D. D'abord, le regime des fluctuations gaussiennes est tres bien decrit par le modele d'Aslamazov-Larkin en deux dimensions. Ensuite, le regime de fluctuations critiques, se trouvant a plus basse temperature que le regime gaussien, est tres bien decrit par la physique 2D de Kosterlitz-Thouless. Dans cette analyse, les deux regimes ont des temperatures critiques coherentes entre elles, ce qui semble confirmer ce scenario 2D. Une analyse des donnees dans le cadre de fluctuations 3D est exploree mais donne des conclusions incoherentes. Les resultats pour les autres dopages sont qualitativement equivalents avec le dopage optimal et permettent donc une explication purement 2D. Par contre, contrairement au dopage optimal, les effets du desordre semblent etre tres importants. Une analyse detaillee de tous ces resultats semble indiquer que les signatures 2D in identifiees proviennent vraisemblablement de plans paralleles decouples formes d'environ 4 plans CuO2 couples. On discute de cette mise en ordre partielle comme une possible consequence d'une separation de phase isolante antiferromagnetique/supraconducteur. La largeur de la transition en fonction du dopage est aussi analysee dans le but de mettre en lumiere un possible effet du pseudogap. On montre que nos mesures ne supportent pas une telle interpretation.

Suivi après le traitement du cancer du sein

PubMed Central

Sisler, Jeffrey; Chaput, Geneviève; Sussman, Jonathan; Ozokwelu, Emmanuel

2016-01-01

Résumé Objectif Offrir aux médecins de famille un résumé des recommandations fondées sur les données probantes pour guider les soins aux survivantes traitées pour le cancer du sein. Qualité des données Une recherche documentaire a été effectuée dans MEDLINE entre 2000 et 2016 à l’aide des mots-clés anglais suivants : breast cancer, survivorship, follow-up care, aftercare, guidelines et survivorship care plans, en se concentrant sur la revue des lignes directrices publiées récemment par les organismes nationaux de cancérologie. Les données étaient de niveaux I à III. Message principal Les soins aux survivantes comportent 4 facettes : surveillance et dépistage, prise en charge des effets à long terme, promotion de la santé et coordination des soins. La surveillance des récidives ne se traduit que par une mammographie annuelle, et le dépistage d’autres cancers doit suivre les lignes directrices basées sur la population. La prise en charge des effets à long terme du cancer et de son traitement aborde des problèmes courants tels la douleur, la fatigue, le lymphœdème, la détresse et les effets indésirables des médicaments, de même que les préoccupations à long terme comme la santé du cœur et des os. La promotion de la santé met en relief les bienfaits de l’activité chez les survivantes du cancer, avec l’accent mis sur l’activité physique. Les soins aux survivantes sont de meilleure qualité lorsque divers services et professionnels de la santé participent aux soins, et le médecin de famille joue un rôle important dans la coordination des soins. Conclusion Les médecins de famille sont de plus en plus souvent les principaux fournisseurs de soins de suivi après le traitement du cancer du sein. Le cancer du sein doit être considéré comme une affection médicale chronique, même chez les femmes en rémission, et les patientes profitent de la même approche que celle utilisée pour les autres affections chroniques en soins de première ligne. PMID:27737992

Carapace surface architecture facilitates camouflage of the decorator crab Tiarinia cornigera.

PubMed

Sanka, Immanuel; Suyono, Eko Agus; Rivero-Müller, Adolfo; Alam, Parvez

2016-09-01

This paper elucidates the unique setal morphology of the decorator crab Tiarinia cornigera, and further presents evidence to that setal morphology promotes micro-organism nucleation and adhesion. The carapace of this crab is covered by clusters of setae, each comprising a hollow acicular stem that is enveloped by a haystack-like structure. Using computational fluid dynamics, we find that these setae are responsible for manipulating water flow over the carapace surface. Micro-organisms in the sea water, nest in areas of flow stagnation and as a result, nucleate to and biofoul the setae by means of chemical adhesion. Attached micro-organisms secrete extracellular polymeric substances, which we deduce must also provide an additional element of chemical adhesion to mechanically interlocked mesoscopic and macroscopic biomatter. By coupling physical and chemical methods for adhesion, T. cornigera is able to hierarchically decorate its carapace. Our paper brings to light the unique decorator crab carapace morphology of T. cornigera; and furthermore evidences its function in micro-organism nucleation and adhesion. We show how this special carapace morphology directs and guides water flow to form nesting regions of water stagnation where micro-organisms can nucleate and adhere. In the literature, decorator crab carapaces are presumed to be able to mechanically interlock biomatter as camouflage using hook-like setal outgrowths. T. cornigera contrarily exhibits clusters of hay-stack like structures. By encouraging micro-organism adhesion to the carapace setae, T. cornigera is able to effectively attach biomatter using both chemical and physical principles of adhesion. T. cornigera essentially has a super-biofouling carapace surface, for at least micro-organisms. Our work will have an impact on researchers interested in biofouling, adhesion, biomedical and purification filter systems, and in the development of novel biomimetic surfaces with tailored properties. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Description of Eucyclops tziscao sp. n., E. angeli sp. n., and a new record of E. festivus Lindberg, 1955 (Cyclopoida, Cyclopidae, Eucyclopinae) in Chiapas, Mexico

PubMed Central

Gutiérrez-Aguirre, Martha Angélica; Mercado-Salas, Nancy Fabiola; Cervantes-Martínez, Adrián

2013-01-01

Abstract Two new species of the freshwater cyclopoid genera Eucyclops are described, Eucyclops tziscao sp. n. and E. angeli sp. n. Both species belong to the serrulatus-group defined by morphological features such as: the presence of distal spinules or hair-like setae (groups N1 and N2) on frontal surface of antennal basis; the fourth leg coxa with a strong inner spine that bears dense setules on inner side, yet proximally naked (large gap) on outer side; and a 12-segmented antennule with smooth hyaline membrane on the three distalmost segments. Eucyclops tziscao sp. n. is morphologically similar to E. bondi and E. conrowae but differs from these species in having a unique combination of characters, including a caudal ramus 4.05±0.25 times as long as wide, lateral seta of Enp3P4 modified as a strong, sclerotized blunt seta, coxal spine of fourth leg with inner spinule-like setules distally, and sixth leg of males bearing a strong and long inner spine 2.3 times longer than median seta. Eucyclops angeli sp. n. can be distinguished by an unique combination of morphological features: the short caudal ramus; the long spine on the sixth antennular segment of A1; the presence of one additional group of spinules (N12’) on the caudal surface of A2; the presence of long setae in females, or short spinules in males on the lateral margin of fourth prosomite; the strong ornamentation of the intercoxal sclerite of P4, specially group I modified as long denticles; the distal modified setae of Exp3P3 and Exp3P4 in females and males; and the short lateral seta of P5. Finally, we report on a new record of E. festivus in México, and add data on morphology of the species. PMID:24294085

Unique Association of Rare Cardiovascular Disease in an Athlete With Ventricular Arrhythmias.

PubMed

Santomauro, V; Contursi, M; Dellegrottaglie, S; Borsellino, G

2015-01-01

Ventricular arrhythmias are a leading cause of non-elegibility to competitive sport. The failure to detect a significant organic substrate in the initial stage of screening does not preclude the identification of structural pathologies in the follow-up by using advanced imaging techniques. Here we report the case of a senior athlete judged not elegible because an arrhythmia with the morphology consistent with the origin of the left ventricle, in which subsequent execution of a cardiac MR and a thoracic CT scan has allowed the identification of an unique association between an area of myocardial damage, probable site of origine of the arrhythma, and a rare aortic malformation.

Lava Morphology Classification of a Fast-Spreading Ridge Using Deep-Towed Sonar Data: East Pacific Rise

NASA Astrophysics Data System (ADS)

Meyer, J.; White, S.

2005-05-01

Classification of lava morphology on a regional scale contributes to the understanding of the distribution and extent of lava flows at a mid-ocean ridge. Seafloor classification is essential to understand the regional undersea environment at midocean ridges. In this study, the development of a classification scheme is found to identify and extract textural patterns of different lava morphologies along the East Pacific Rise using DSL-120 side-scan and ARGO camera imagery. Application of an accurate image classification technique to side-scan sonar allows us to expand upon the locally available visual ground reference data to make the first comprehensive regional maps of small-scale lava morphology present at a mid-ocean ridge. The submarine lava morphologies focused upon in this study; sheet flows, lobate flows, and pillow flows; have unique textures. Several algorithms were applied to the sonar backscatter intensity images to produce multiple textural image layers useful in distinguishing the different lava morphologies. The intensity and spatially enhanced images were then combined and applied to a hybrid classification technique. The hybrid classification involves two integrated classifiers, a rule-based expert system classifier and a machine learning classifier. The complementary capabilities of the two integrated classifiers provided a higher accuracy of regional seafloor classification compared to using either classifier alone. Once trained, the hybrid classifier can then be applied to classify neighboring images with relative ease. This classification technique has been used to map the lava morphology distribution and infer spatial variability of lava effusion rates along two segments of the East Pacific Rise, 17 deg S and 9 deg N. Future use of this technique may also be useful for attaining temporal information. Repeated documentation of morphology classification in this dynamic environment can be compared to detect regional seafloor change.

Is Supramolecular Filament Chirality the Underlying Cause of Major Morphology Differences in Amyloid Fibrils?

PubMed Central

2015-01-01

The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for “normal” left-hand-helical filaments and below pH 2 for “reversed” right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218–289) prion, and a short polypeptide fragment of transthyretin, TTR (105–115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases. PMID:24484302

Is supramolecular filament chirality the underlying cause of major morphology differences in amyloid fibrils?

PubMed

Kurouski, Dmitry; Lu, Xuefang; Popova, Ludmila; Wan, William; Shanmugasundaram, Maruda; Stubbs, Gerald; Dukor, Rina K; Lednev, Igor K; Nafie, Laurence A

2014-02-12

The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for "normal" left-hand-helical filaments and below pH 2 for "reversed" right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218-289) prion, and a short polypeptide fragment of transthyretin, TTR (105-115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases.

Genetic, morphological, and spectral characterization of relictual Niobrara River hybrid aspens (Populus × smithii).

PubMed

Deacon, Nicholas John; Grossman, Jake Joseph; Schweiger, Anna Katharina; Armour, Isabella; Cavender-Bares, Jeannine

2017-12-01

Aspen groves along the Niobrara River in Nebraska have long been a biogeographic curiosity due to morphological differences from nearby remnant Populus tremuloides populations. Pleistocene hybridization between P. tremuloides and P. grandidentata has been proposed, but the nearest P. grandidentata populations are currently several hundred kilometers east. We tested the hybrid-origin hypothesis using genetic data and characterized putative hybrids phenotypically. We compared nuclear microsatellite loci and chloroplast sequences of Niobrara River aspens to their putative parental species. Parental species and putative hybrids were also grown in a common garden for phenotypic comparison. On the common garden plants, we measured leaf morphological traits and leaf-level spectral reflectance profiles, from which chemical traits were derived. The genetic composition of the three unique Niobrara aspen genotypes is consistent with the hybridization hypothesis and with maternal chloroplast inheritance from P. grandidentata . Leaf margin dentition and abaxial pubescence differentiated taxa, with the hybrids showing intermediate values. Spectral profiles allowed statistical separation of taxa in short-wave infrared wavelengths, with hybrids showing intermediate values, indicating that traits associated with internal structure of leaves and water absorption may vary among taxa. However, reflectance values in the visible region did not differentiate taxa, indicating that traits related to pigments are not differentiated. Both genetic and phenotypic results support the hypothesis of a hybrid origin for these genetically unique aspens. However, low genetic diversity and ongoing ecological and climatic threats to the hybrid taxon present a challenge for conservation of these relictual boreal communities. © 2017 Botanical Society of America.

Molecular and morphological characterization of local apple cultivars in Southern Spain.

PubMed

Pérez-Romero, L F; Suárez, M P; Dapena, E; Rallo, P

2015-02-20

The number of local and traditional fruit cultivars in Andalusia (Southern Spain) has decreased dramatically since the 1970s when new commercial cultivars from breeding programs were introduced, replacing old varieties, and thus decreasing genetic diversity. The present study was included in a genetic resources project with the objective of identifying and preserving traditional fruit tree cultivars in Southern Spain. The goal of this study was to begin the characterization of 29 apple accessions (Malus x domestica Borkh) belonging to 13 traditional cultivar denominations. For molecular characterization studies, 12 simple sequence repeat markers previously developed for apple species were used. Morphological characterization was performed using 33 fruit traits. A total of 115 alleles were amplified for the 12 loci, ranging from 7 (CH01h01, CH01h10, and GD 12) to 13 alleles per locus (CH02c11). Forty-one alleles were unique to specific genotypes. The locus with the highest number of detected unique alleles was CH01f03b with 6 alleles. Expected heterozygosity ranged from 0.74 for CH01h10 to 0.88 for CH02c11, with an average of 0.82. Observed heterozygosity varied from 0.45 for CH01h01 to 1.0 for CH02d08, with an average of 0.86. Three homonyms were found for accessions belonging to varieties 'Maguillo', 'Pero Minguela', and 'Castellana'. The most discriminant morphological characters studied revealed no homonyms or synonyms among cultivar denominations, although they are useful for describing varietal characteristics that have not been previously defined.

Clinically Detectable Dental Identifiers Observed in Intra-oral Photographs and Extra-oral Radiographs, Validated for Human Identification Purposes.

PubMed

Angelakopoulos, Nikolaos; Franco, Ademir; Willems, Guy; Fieuws, Steffen; Thevissen, Patrick

2017-07-01

Screening the prevalence and pattern of dental identifiers contributes toward the process of human identification. This research investigated the uniqueness of clinical dental identifiers in photographs and radiographs. Panoramic and lateral cephalometric radiographs and five intra-oral photographs of 1727 subjects were used. In a target set, two observers examined different subjects. In a subset, both observers examined the same subjects (source set). The distance between source and target subjects was quantified for each identifier. The percentage of subjects in the target set being at least as close as the correct subject was assessed. The number of molars (34.6%), missing teeth (42%), and displaced teeth (59.9%) were the most unique identifiers in photographs and panoramic and lateral cephalometric radiographs, respectively. The pattern of rotated teeth (14.9%) was the most unique in photographs, while displaced teeth was in panoramic (37.6%) and lateral cephalometric (54.8%) radiographs. Morphological identifiers were the most unique, highlighting their importance for human identifications. © 2016 American Academy of Forensic Sciences.

Effet de la poudre de verre sur le fluage du C-S-H

NASA Astrophysics Data System (ADS)

Danilova, Maryna

Glass is a unique inert material that could be recycled many times without changing its physical and chemical properties. Nevertheless, for some reason, large quantities of glass are still not recycled and therefore are stored as a waste. Its alternative recycling has become, since long, a major environmental problem. Moreover, glass is a potentially useful material for the development of ecological concrete, consequently, this way valorization seems to be imminent. In this research, characterization of the creep of concrete incorporating waste glass in powder form, i.e. glass powder (GP) as a supplementary cementitious material (GP-concrete) was carried out at a macro- and nanolevels. First, results from experimental study on the under load behaviour of GP-concrete are presented. Different types of strain occurring under load or after unload were discussed: quasi-instantaneous deformation, total mechanical deformation due to the maintained uniaxial compressive load during 1 year, total creep, basic creep, elastic recovery and total recovery. Shrinkage under drying conditions and endogenous shrinkage were also studied. After 1 year creep, the effects of constant load and drying on residual strength were also examined. A comparison was made concerning the final state of the porosity. Afterwards, the thesis reveals the results of tests conducted on the cement paste, going down to its composition and properties of the hydrated phases, in particular of calcium silicate hydrates (C-S-H). All of this, in order to conclude on the harmlessness use of GP regarding to the creep. Keywords : Glass powder, Air-entrained concrete, Creep, Shrinkage, C-S-H, Nanoindentation

Foreign Exchange Value-at-Risk with Multiple Currency Exposure: A Multivariate and Copula Generalized Autoregressive Conditional Heteroskedasticity Approach

DTIC Science & Technology

2014-11-01

du taux de change, et les responsables de la gestion interne se voient donc pressés de trouver des ... mesurer les effets négatifs que peuvent avoir les fluctuations mo- nétaires sur le budget et la planification du MDN, il faut connaître le poids des ...qualités comparables et qu’ils permettent d’effectuer une meilleure évaluation du risque qu’avec la méthode courante. On obtient désormais des estimations de

Swell Across the Continental Shelf

DTIC Science & Technology

2001-09-01

Arlington, VA The views expressed in this thesis are those of the author and do not reflect the official policy or position of the Department of Defense ...le terme de source, tandis que les effets de la réfraction et du levage causés par les variations de profondeur aux échelles sous-maille sont...précisement pris en compte grâce aux rayons pré- calculés. Ainsi ce modèle peut être appliqué à de vastes zones côtières avec des maillages

C3I for Crisis, Emergency and Consequence Management (C3I pour la gestion des crises, des urgences et de leurs consequences)

DTIC Science & Technology

2009-05-01

Quelque soit le contexte, l’aide à la décision passe par une analyse en profondeur de trois (3) aspects importants interdépendants, à savoir le...information, including suggestions for reducing this burden to Department of Defense , Washington Headquarters Services, Directorate for Information...type de menace, nécessite en effet d’adopter une approche collective de la sécurité étendue à une coopération avec de multiples organisations civiles

Biological Effects of Ionising Radiation and Countermeasures (Les effets biologiques des rayonnements ionisants et leurs contre-mesures)

DTIC Science & Technology

2018-01-01

promote cooperative research and information exchange, and secondly an in-house delivery business model where S&T activities are conducted in a NATO...Panel These Panels and Group are the power-house of the collaborative model and are made up of national representatives as well as recognised world...of Radiation Injury and Recovery 1-31 1.3.3.2 Mini-Pig Model of Acute Radiation Syndrome ( ARS ) 1-31 1.3.3.3 Medical Countermeasures (MedCM) 1-32

Hygrothermal Effects in Continuous Fibre Reinforced Composites. Part I. Thermal and Moisture Diffusion in Composite Materials (Effets Hygrothermiques dans les Composites a Renfort de Fibre Continu. Partie I. Diffusion de L’Humidite et de la Chaleur dans les Materiaux Composites)

DTIC Science & Technology

1983-01-01

considered important, complete, and a lasting contribution to existing knowledge. -’ Mechanical Engineering Reports (MS): Scientific and technical information...pertaining to investigations outside aeronautics considered important, complete, and a lasting contribution to existing knowledge. * AERONAUTICAL...NOTES (AN): Information les~s broad in scope but nevertheless of importance as a * contribution to existing knowledge. LABORATORY TECHNICAL REPORTS (LTR

Research on Modelling the Effects of Personal Hearing Protection and Communications Devices on Speech Intelligibility in Noise

DTIC Science & Technology

2011-06-01

performance ont été observées entre les différents groupes de sujets en ce qui a trait à l’effet du mode d’utilisation passif comparativement à l’écoute sans...work is staged over three fiscal/reporting periods as follows: Stage I (ending March 31st 2009): Design a Study Stage II (ending March 31st...under PWGSC Contract No. W7711-088145/001/TOR. It presents the study design and methods devised in Stage I, subjective and objective data collected

Unique Turbinal Morphology in Horseshoe Bats (Chiroptera: Rhinolophidae).

PubMed

Curtis, Abigail A; Simmons, Nancy B

2017-02-01

The mammalian nasal fossa contains a set of delicate and often structurally complex bones called turbinals. Turbinals and associated mucosae function in regulating respiratory heat and water loss, increasing surface area for olfactory tissue, and directing airflow within the nasal fossa. We used high-resolution micro-CT scanning to investigate a unique maxilloturbinal morphology in 37 species from the bat family Rhinolophidae, which we compared with those of families Hipposideridae, Megadermatidae, and Pteropodidae. Rhinolophids exhibit numerous structural modifications along the nasopharyngeal tract associated with emission of high duty cycle echolocation calls via the nostrils. In rhinolophids, we found that the maxilloturbinals and a portion of ethmoturbinal I form a pair of strand-like bony structures on each side of the nasal chamber. These structures project anteriorly from the transverse lamina and complete a hairpin turn to project posteriorly down the nasopharyngeal duct, and vary in length among species. The strand-like maxilloturbinals in Rhinolophidae were not observed in our outgroups and represent a synapomorphy for this family, and are unique in form among mammals. Within Rhinolophidae, maxilloturbinal size and cross-sectional shape were correlated with phylogeny. We hypothesize that strand-shaped maxilloturbinals may function to reduce respiratory heat and water loss without greatly impacting echolocation call transmission since they provide increased mucosal surface area for heat and moisture exchange but occupy minimal space. Alternatively, they may play a role in transmission of echolocation calls since they are located directly along the path sound travels between the larynx and nostrils during call emission. Anat Rec, 300:309-325, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Detection de la fin de la compaction des anodes par le son

NASA Astrophysics Data System (ADS)

Sanogo, Bazoumana

L'objectif de ce projet etait de developper un outil de controle en temps reel du temps de compaction en se servant du son genere par le vibrocompacteur pendant le formage des anodes crues. Ainsi, une application a ete developpee pour l'analyse des sons enregistres. Des essais ont ete realises avec differents microphones pour une meilleure qualite des mesures et un a ete choisi pour la suite du projet. De meme, differents tests ont ete realises sur des anodes de laboratoire ainsi que des anodes a l'echelle industrielle afin de mettre en place une methode pour la detection du temps optimal necessaire au formage des anodes. Les travaux au laboratoire de carbone a l'Universite du Quebec a Chicoutimi (UQAC) ont consiste a l'enregistrement de son des anodes fabriquees sur place avec differentes configurations; et a la caracterisation de certaines anodes de l'usine. Les anodes fabriquees au laboratoire sont reparties en deux groupes. Le premier regroupe les anodes pour la validation de notre methode. Ce sont des anodes produites avec des temps de compaction differents. Le laboratoire de carbone a l'UQAC est unique et il est possible de produire des anodes avec les memes proprietes que celles des anodes industrielles. Par consequent, la validation initialement prevue a l'usine a ete effectuee avec les anodes de laboratoire. Le deuxieme groupe a servi a etudier les effets des matieres premieres sur le temps de compaction. Le type de coke et le type de brai ont constitue les differentes variations dans ce deuxieme groupe. Quant aux tests et mesures a l'usine, ils ont ete realises en trois campagnes de mesure. La premiere campagne en juin 2014 a servi a standardiser et a trouver le meilleur positionnement des appareils pour les mesures, a regler le logiciel et a faire les premieres mesures. Une deuxieme campagne en mai 2015 a fait l'objet d'enregistrement de son en classant les anodes selon differents temps de compaction. La troisieme et derniere campagne en decembre 2015 a ete le lieu de tests finaux a l'usine en fabriquant des anodes avec differents criteres (variation du temps de compaction, taux de brai, arret manuel du compacteur, variation de la pression des ballons du haut du compacteur). Ces anodes ont ete ensuite analysees au laboratoire a l'UQAC. En parallele a ces travaux precites, l'amelioration de l'application d'analyse du son a ete faite avec le choix des parametres d'analyse et leur standardisation. Les resultats des premiers tests au laboratoire et ceux de la campagne de juin 2014 ont montre que la formation des anodes se fait suivant trois etapes : rearrangement des particules et du brai, compaction et consolidation et enfin la finition. Ces travaux ont montre en outre que le temps de compaction joue un role tres important dans la definition des proprietes finales des anodes. Ainsi, en plus du type de brai, du taux de brai et du type de coke, il faut tenir compte du temps de sur-compaction et de sous-compaction. En effet, ceci a ete demontre a travers les deux validations qui ont ete realisees. Les resultats de la caracterisation des echantillons (venant des anodes de la campagne de decembre 2015) ont montre qu'une anode compactee a un temps optimal acquiert une bonne resistance a la compression et sa resistivite electrique baisse. En outre, on note que le temps de compaction dans notre cas a baisse legerement avec l'augmentation de la pression des ballons de haut du vibrocompacteur. Ce qui a eu pour effet d'augmenter la densite crue de l'anode. Toutefois, il faut s'abstenir de generaliser ce constat car le nombre d'anodes testees est faible dans notre cas. Par ailleurs, cette etude montre que le temps necessaire pour le formage d'une anode croit avec l'augmentation du taux de brai et baisse legerement avec l'augmentation de la pression des ballons. (Abstract shortened by ProQuest.).

Surface topography during neural stem cell differentiation regulates cell migration and cell morphology.

PubMed

Czeisler, Catherine; Short, Aaron; Nelson, Tyler; Gygli, Patrick; Ortiz, Cristina; Catacutan, Fay Patsy; Stocker, Ben; Cronin, James; Lannutti, John; Winter, Jessica; Otero, José Javier

2016-12-01

We sought to determine the contribution of scaffold topography to the migration and morphology of neural stem cells by mimicking anatomical features of scaffolds found in vivo. We mimicked two types of central nervous system scaffolds encountered by neural stem cells during development in vitro by constructing different diameter electrospun polycaprolactone (PCL) fiber mats, a substrate that we have shown to be topographically similar to brain scaffolds. We compared the effects of large fibers (made to mimic blood vessel topography) with those of small-diameter fibers (made to mimic radial glial process topography) on the migration and differentiation of neural stem cells. Neural stem cells showed differential migratory and morphological reactions with laminin in different topographical contexts. We demonstrate, for the first time, that neural stem cell biological responses to laminin are dependent on topographical context. Large-fiber topography without laminin prevented cell migration, which was partially reversed by treatment with rock inhibitor. Cell morphology complexity assayed by fractal dimension was inhibited in nocodazole- and cytochalasin-D-treated neural precursor cells in large-fiber topography, but was not changed in small-fiber topography with these inhibitors. These data indicate that cell morphology has different requirements on cytoskeletal proteins dependent on the topographical environment encountered by the cell. We propose that the physical structure of distinct scaffolds induces unique signaling cascades that regulate migration and morphology in embryonic neural precursor cells. J. Comp. Neurol. 524:3485-3502, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

A Comparative Morphological Study of the Jugal and Quadratojugal in Early Birds and Their Dinosaurian Relatives.

PubMed

Wang, Min; Hu, Han

2017-01-01

The zygoma (called jugal bar) in modern birds accounts for a large portion of the ventral margin of the cranium. As a delicate and rod-like element, the jugal bar is functionally integrated into the avian cranial kinesis, a unique property that allows the beak to be elevated or depressed with respect to the braincase and thus distinguishes birds from all other modern vertebrates. Developmental studies show that the jugal bar of modern birds is formed by the fusion of the jugal and quadratojugal that are ossified from separated centers. However, those two bones are unfused and exhibit complicated morphological variations in basal birds and their dinosaurian relatives. Moreover, the jugal and quadratojugal form rigid articulations with the postorbital and squamosal, respectively, consequently hindering the movement of the upper jaw in most non-avian dinosaurs and some basal birds. A comparative study of the jugal and quadratojugal morphology of basal birds and their close relatives such as dromaeosaurids and oviraptorids elucidates how modern birds has achieved its derived jugal bar morphology, and sheds light on the evolution of the postorbital configuration of birds. We propose that numerous morphological modifications of those two elements (morphology changes and reduced articulation with other elements) took place in early bird history, and some of them pertinent to the refinement of the cranial kinesis. Anat Rec, 300:62-75, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

In-depth understanding of the relation between CuAlO₂ particle size and morphology for ozone gas sensor detection at a nanoscale level.

PubMed

Thirumalairajan, S; Mastelaro, Valmor R; Escanhoela, Carlos A

2014-12-10

A morphology-dependent nanomaterial for energy and environment applications is one of the key challenges for materials science and technology. In this study, we investigate the effect of the particle size of CuAlO2 nanostructures prepared through the facile and hydrothermal process to detect ozone gas. Phase analysis and structural information were obtained using X-ray diffraction and micro-Raman studies. The chemical states of CuAlO2 atomic species were determined by X-ray photoelectron spectroscopy. Electron microscopy images revealed the flower and hexagonal shape constituted of pentagon and oval CuAlO2 nanoparticles with average size ∼40 and 80 nm. The specific surface area was measured and found to be 59.8 and 70.8 m(2) g(-1), respectively. The developed CuAlO2 nanostructures not only possess unique morphology but also influence the ozone gas sensing performance. Among the two structures, CuAlO2, with hexagonal morphology, exhibited superior ozone detection for 200 ppb at 250 °C, with a response and good recovery time of 25 and 39 s compared to the flower morphology (28 and 69 s). These results show that not only does the morphology play an major role but also the particle size, surface area, gas adsorption/desorption, and grain-grain contact, as proposed in the gas sensing mechanism. Finally, we consider CuAlO2 material as a good candidate for environment monitoring applications.

Controls on Lava Flow Morphology and Propagation: Using Laboratory Analogue Experiments

NASA Astrophysics Data System (ADS)

Peters, S.; Clarke, A. B.

2017-12-01

The morphology of lava flows is controlled by eruption rate, composition, cooling rate, and topography [Fink and Griffiths, 1990; Gregg and Fink, 2000, 2006]. Lava flows are used to understand how volcanoes, volcanic fields, and igneous provinces formed and evolved [Gregg and Fink., 1996; Sheth, 2006]. This is particularly important for other planets where compositional data is limited and historical context is nonexistent. Numerical modeling of lava flows remains challenging, but has been aided by laboratory analog experiments [Gregg and Keszrthelyi, 2004; Soule and Cashman, 2004]. Experiments using polyethylene glycol (PEG) 600 wax have been performed to understand lava flow emplacement [Fink and Griffiths, 1990, 1992; Gregg and Fink, 2000]. These experiments established psi (hereafter denoted by Ψ), a dimensionless parameter that relates crust formation and advection timescales of a viscous gravity current. Four primary flow morphologies corresponding to discreet Ψ ranges were observed. Gregg and Fink [2000] also investigated flows on slopes and found that steeper slopes increase the effective effusion rate producing predicted morphologies at lower Ψ values. Additional work is needed to constrain the Ψ parameter space, evaluate the predictive capability of Ψ, and determine if the preserved flow morphology can be used to indicate the initial flow conditions. We performed 514 experiments to address the following controls on lava flow morphology: slope (n = 282), unsteadiness/pulsations (n = 58), slope & unsteadiness/pulsations (n = 174), distal processes, and emplacement vs. post-emplacement morphologies. Our slope experiments reveal a similar trend to Gregg and Fink [2000] with the caveat that very high and very low local & source eruption rates can reduce the apparent predictive capability of Ψ. Predicted Ψ morphologies were often produced halfway through the eruption. Our pulse experiments are expected to produce morphologies unique to each eruption rate and promote tube formation and compound flows. Post-emplacement morphologies are modified by a variety of factors (e.g. solidification, deflation), which may not preserve the initial morphology produced during an eruption. Relating this morphology to the eruption conditions is pertinent to understanding the evolution of planetary surfaces.

Processes and rates of sediment and wood accumulation in the headwater streams of the Oregon Coast Range, U.S.A.

Treesearch

C. L. May; R. E. Gresswell

2003-01-01

Abstract - Channels that have been scoured to bedrock by debris flows provide unique opportunities to calculate the rate of sediment and wood accumulation in low-order streams, to understand the temporal succession of channel morphology following disturbance, and to make inferences about processes associated with input and transport of sediment. Dendrochronology was...

Phylogeny of Priapulida.

PubMed

Shapeero, W L

1961-03-24

The systematic position of the small invertebrate group, Priapulida, is uncertain. In more recent publications they are classified usually as pseudocoelomates in the division Aschelminthes. A histological investigation of Priapulus caudatus, a widely distributed species, reveals the body cavity to be a coelom, its lining a peritoneum. These features, and others, indicate the priapulids to be. coelomates rather than pseudocoelomates. Unique morphology perhaps qualifies the group for the status of phylum.

Synthesis and Technological Innovation of Applying Oxide Nanomaterials in Wastewater Treatment by Flotation

NASA Astrophysics Data System (ADS)

Covaliu, C. I.; Moga, I. C.; Matache, M. G.; Paraschiv, G.; Gageanu, I.; Vasile, E.

2018-06-01

The appearance and development of nanotechnology gave new and efficient modalities for pollutants removal from wastewaters by using new compounds called nanomaterials which possess unique structural and morphological properties. In this paper we investigated the application of CoFe2O4 nanomaterial for increasing the efficiency of oily wastewater treatment by flotation. CoFe2O4 nanomaterial was prepared by precipitation method. Prior testing their application in wastewater treatment by flotation, the oxide nanomaterial was structural and morphological characterized by XRD and TEM analyses. The influence of CoFe2O4nanomaterial on oily wastewater depollution by flotation process was investigated by measuring the following parameters: treatment efficiency [%] and the stability of froth.

Influence of bases on hydrothermal synthesis of titanate nanostructures

NASA Astrophysics Data System (ADS)

Sikhwivhilu, Lucky M.; Sinha Ray, Suprakas; Coville, Neil J.

2009-03-01

A hydrothermal treatment of titanium dioxide (TiO2) with various bases (i.e., LiOH, NaOH, KOH, and NH4OH) was used to prepare materials with unique morphologies, relatively small crystallite sizes, and large specific surface areas. The experimental results show that the formation of TiO2 is largely dependent on the type, strength and concentration of a base. The effect of the nature of the base used and the concentration of the base on the formation of nanostructures were investigated using X-ray diffraction, Raman spectroscopy, transmission and scanning electron microscopy, as well as surface area measurements. Sodium hydroxide (NaOH) and potassium hydroxide (KOH) were both used to transform the morphology of starting TiO2 material.

Preparation and Characterization of Mesoporous Nickel derived from Liquid crystalline Template and Evaluation of its Electro catalytic activity towards Methanol Oxidation

NASA Astrophysics Data System (ADS)

Mohanapriya, S.; Renuka devi, R.; Raj, V.

2018-02-01

Mesoporous Nickel has been prepared by electrodeposition using non-ionic surfactant based liquid crystalline template under optimized processing conditions. Physico-chemical properties of mesoporous nickel is systematically characterized through XRD, SEM and AFM analyses. Comparison of electrocatalytic activity of mesoporous nickel with smooth nickel was interrogated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) analyses. Distinctly enhanced electrocatalytic activity with improved surface poisoning resistance related to mesoporous nickel electrode towards methanol oxidation stems from unique mesoporous morphology. This mesoporous morphology with high surface to volume ratio is highly beneficial to promote active catalytic centers to offer readily accessible Pt catalytic sites for MOR, through facilitating mass and electron transports.

Versatile buffer layer architectures based on Ge1-xSnx alloys

NASA Astrophysics Data System (ADS)

Roucka, R.; Tolle, J.; Cook, C.; Chizmeshya, A. V. G.; Kouvetakis, J.; D'Costa, V.; Menendez, J.; Chen, Zhihao D.; Zollner, S.

2005-05-01

We describe methodologies for integration of compound semiconductors with Si via buffer layers and templates based on the GeSn system. These layers exhibit atomically flat surface morphologies, low defect densities, tunable thermal expansion coefficients, and unique ductile properties, which enable them to readily absorb differential stresses produced by mismatched overlayers. They also provide a continuous selection of lattice parameters higher than that of Ge, which allows lattice matching with technologically useful III-V compounds. Using this approach we have demonstrated growth of GaAs, GeSiSn, and pure Ge layers at low temperatures on Si(100). These materials display extremely high-quality structural, morphological, and optical properties opening the possibility of versatile integration schemes directly on silicon.

Archaeocete-like jaws in a baleen whale

PubMed Central

Fitzgerald, Erich M. G.

2012-01-01

The titanic baleen whales (Cetacea, Mysticeti) have a bizarre skull morphology, including an elastic mandibular symphysis, which permits dynamic oral cavity expansion during bulk feeding. How this key innovation evolved from the sutured symphysis of archaeocetes has remained unclear. Now, mandibles of the Oligocene toothed mysticete Janjucetus hunderi show that basal mysticetes had an archaeocete-like sutured symphysis. This archaic morphology was paired with a wide rostrum typical of later-diverging baleen whales. This demonstrates that increased oral capacity via rostral widening preceded the evolution of mandibular innovations for filter feeding. Thus, the initial evolution of the mysticetes' unique cranial form and huge mouths was perhaps not linked to filtering plankton, but to enhancing suction feeding on individual prey. PMID:21849306

Production of zinc oxide nanowires power with precisely defined morphology

NASA Astrophysics Data System (ADS)

Mičová, Júlia; Remeš, Zdeněk; Chan, Yu-Ying

2017-12-01

The interest about zinc oxide is increasing thanks to its unique chemical and physical properties. Our attention has focused on preparation powder of 1D nanostructures of ZnO nanowires with precisely defined morphology include characterization size (length and diameter) and shape controlled in the scanning electron microscopy (SEM). We have compared results of SEM with dynamic light scattering (DLS) technique. We have found out that SEM method gives more accurate results. We have proposed transformation process from ZnO nanowires on substrates to ZnO nanowires powder by ultrasound peeling to colloid followed by lyophilization. This method of the mass production of the ZnO nanowires powder has some advantages: simplicity, cost effective, large-scale and environment friendly.

What Happens during Natural Protein Fibre Dissolution in Ionic Liquids.

PubMed

Chen, Jingyu; Vongsanga, Kylie; Wang, Xungai; Byrne, Nolene

2014-08-28

Here, we monitor the dissolution of several natural protein fibres such as wool, human hair and silk, in various ionic liquids (ILs). The dissolution of protein-based materials using ILs is an emerging area exploring the production of new materials from waste products. Wool is a keratin fibre, which is extensively used in the textiles industry and as a result has considerable amounts of waste produced each year. Wool, along with human hair, has a unique morphology whereby the outer layer, the cuticle, is heavily cross linked with disulphide bonds, whereas silk does not have this outer layer. Here we show how ILs dissolve natural protein fibres and how the mechanism of dissolution is directly related to the structure and morphology of the wool fibre.

Unique organogel formation with macroporous materials constructed by the freeze-drying of aqueous cyclodextrin solutions.

PubMed

Marui, Yasuhiro; Kikuzawa, Akira; Kida, Toshiyuki; Akashi, Mitsuru

2010-07-06

Macroporous cyclodextrin materials (MP-alpha-, beta-, and gamma-CDs) were easily fabricated by the freeze-drying of aqueous solutions of alpha-, beta-, and gamma-CDs. These MP-CDs showed the absorption ability toward various organic solvents and oils to give organogels at ambient temperature. The morphological changes of the MP-CD microstructures were observed through the absorption of organic solvents. In particular, the absorption of polar organic solvents with hydrogen-bond forming ability, including 1,4-dioxane and ethanol, by the MP-CDs caused remarkable morphological changes in the microstructures. The absorption of these polar solvents by MP-alpha- and gamma-CDs resulted in the formation of channel-type assemblies of alpha- and gamma-CDs, respectively.

The future of neuropathology in childhood.

PubMed

Rorke, L B

2000-11-01

The current state of knowledge of pediatric neuropathology is based upon a rich historical heritage dating back many centuries and representing the genius of many people, although, relatively speaking, little specific attention was paid to the unique issues relating to infants and children. Aside from descriptions of morphological features of disease (including tumors), advances in understanding basic pathogenetic mechanisms have flowered only in the recent past. Most exciting has been the progress in molecular biology and genetics, which has yielded a phenomenal bank of information in a short time, uncovering details of genes involved in development of the nervous system and specifically associated with various types of tumors. The future of pediatric neuropathology requires partnership with molecular geneticists whose studies hold promise of defining morphology.

Halloysite clay nanotubes for controlled release of protective agents.

PubMed

Abdullayev, Elshad; Lvov, Yuri

2011-11-01

Halloysite is a naturally occurring clay mineral with submicron sized hollow cylindrical morphology. Halloysite morphology, structure and properties were characterized by using SEM, TEM, XRD, FT-IR spectroscopy, surface electrokinetic (zeta) potential and nitrogen adsorption isotherms. Comparison of the halloysite structure with imogolite was also provided. Halloysite toxicological studies revealed that it is environmentally friendly and biocompatible material. Due to its unique tubular shape and availability in thousands of tons halloysite has potential to be applied as nanocontainers for encapsulation of chemically and biologically active agents such as medicines, pharmaceuticals, antiseptics, corrosion inhibitors, antifouling agents, and doped with them plastics producing smart polymeric nanocomposites with improved mechanical strength. Finally possibility to synthesize metal nanorods within the halloysite lumen was demonstrated.

Graphene-Like 2D Porous Carbon Nanosheets Derived from Cornstalk Pith for Energy Storage Materials

NASA Astrophysics Data System (ADS)

Gao, Kezheng; Niu, Qingyuan; Tang, Qiheng; Guo, Yaqing; Wang, Lizhen

2018-01-01

Biomass materials from different organisms or different parts (even different periods) of the same organism have different microscopic morphologies, hierarchical pore structures and even elemental compositions. Therefore, carbon materials inheriting the unique hierarchical microstructure of different biomass materials may exhibit significantly different electrochemical properties. Cornstalk pith and cornstalk skin (dried by freeze-drying) exhibit significantly different microstructures due to their different biological functions. The cornstalk skin-based carbon (S-carbon) exhibits a thick planar morphology, and the Barrett-Emmett-Teller (BET) surface area is only about 332.07 m2 g-1. However, cornstalk pith-based carbon (P-carbon) exhibits a graphene-like 2D porous nanosheet structure with a rough, wrinkled morphology, and the BET surface area is about 805.17 m2 g-1. In addition, a P-carbon supercapacitor exhibits much higher specific capacitance and much better rate capability than an S-carbon supercapacitor in 6 M potassium hydroxide (KOH) electrolyte.

Morphology-Tuned Synthesis of Nickel Cobalt Selenides as Highly Efficient Pt-Free Counter Electrode Catalysts for Dye-Sensitized Solar Cells.

PubMed

Qian, Xing; Li, Hongmei; Shao, Li; Jiang, Xiancai; Hou, Linxi

2016-11-02

In this work, morphology-tuned ternary nickel cobalt selenides based on different Ni/Co molar ratios have been synthesized via a simple precursor conversion method and used as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). The experimental facts and mechanism analysis clarified the possible growth process of product. It can be found that the electrochemical performance and structures of ternary nickel cobalt selenides can be optimized by tuning the Ni/Co molar ratio. Benefiting from the unique morphology and tunable composition, among the as-prepared metal selenides, the electrochemical measurements showed that the ternary nickel cobalt selenides exhibited a more superior electrocatalytic activity in comparison with binary Ni and Co selenides. In particular, the three-dimensional dandelion-like Ni 0.33 Co 0.67 Se microspheres delivered much higher power conversion efficiency (9.01%) than that of Pt catalyst (8.30%) under AM 1.5G irradiation.

Exceptional preservation reveals gastrointestinal anatomy and evolution in early actinopterygian fishes

PubMed Central

Argyriou, Thodoris; Clauss, Marcus; Maxwell, Erin E.; Furrer, Heinz; Sánchez-Villagra, Marcelo R.

2016-01-01

Current knowledge about the evolutionary morphology of the vertebrate gastrointestinal tract (GIT) is hindered by the low preservation potential of soft tissues in fossils. Exceptionally preserved cololites of individual †Saurichthys from the Middle Triassic of Switzerland provide unique insights into the evolutionary morphology of the GIT. The GIT of †Saurichthys differed from that of other early actinopterygians, and was convergent to that of some living sharks and rays, in exhibiting up to 30 turns of the spiral valve. Dissections and literature review demonstrate the phylogenetic diversity of GIT features and signs of biological factors that influence its morphology. A phylogenetically informed analysis of a dataset containing 134 taxa suggests that body size and phylogeny are important factors affecting the spiral valve turn counts. The high number of turns in the spiral valve of †Saurichthys and some recent sharks and rays reflect both energetically demanding lifestyles and the evolutionary histories of the groups. PMID:26732746

Investigation on large-area fabrication of vivid shark skin with superior surface functions

NASA Astrophysics Data System (ADS)

Chen, Huawei; Zhang, Xin; Ma, Lingxi; Che, Da; Zhang, Deyuan; Sudarshan, T. S.

2014-10-01

Shark skin has attracted worldwide attention because of its superior drag reduction, antifouling performance induced from its unique surface morphology. Although the vivid shark skin has been fabricated by a bio-replicated micro-imprinting approach in previous studies and superior drag reduction effect has been validated in water tunnel, continuous large-area fabrication is still an obstacle to wide apply. In this paper, one novel bio-replication coating technology is proposed for large-area transfer of shark skin based on rapid UV curable paint. Apart from design of coating system, bio-replication accuracy of surface morphology was validated about 97% by comparison between shark skin template and coating surface morphology. Finally, the drag reduction and anti-fouling function of coating surface were tested in water tunnel and open algae pond respectively. Drag reduction rate of coating surface was validated about 12% higher and anti-fouling was proved to about hundred times ameliorate, all of which are more excellent than simple 2D riblet surface.

Morphological awareness as a function of semantics, phonology, and orthography and as a predictor of reading comprehension in Chinese.

PubMed

Li, Hong; Dronjic, Vedran; Chen, X I; Li, Yixun; Cheng, Yahua; Wu, Xinchun

2017-09-01

This study investigates the contributions of semantic, phonological, and orthographic factors to morphological awareness of 413 Chinese-speaking students in Grades 2, 4, and 6, and its relationship with reading comprehension. Participants were orally presented with pairs of bimorphemic compounds and asked to judge whether the first morphemes of the words shared a meaning. Morpheme identity (same or different), whole-word semantic relatedness (high or low), orthography (same or different), and phonology (same or different) were manipulated. By Grade 6, children were able to focus on meaning similarities across morphemes while ignoring the distraction of form, but they remained influenced by whole-word semantic relatedness. Children's ability to overcome the distraction of phonology consistently improved with age, but did not reach ceiling, whereas the parallel ability for orthography reached ceiling at Grade 6. Morphological judgment performance was a significant unique predictor of reading comprehension when character naming and vocabulary knowledge were accounted for.

Study of Structural Morphology of Hemp Fiber from the Micro to the Nanoscale

NASA Astrophysics Data System (ADS)

Wang, Bei; Sain, Mohini; Oksman, Kristiina

2007-03-01

The focus of this work has been to study how high pressure defibrillation and chemical purification affect the hemp fiber morphology from micro to nanoscale. Microscopy techniques, chemical analysis and X-ray diffraction were used to study the structure and properties of the prepared micro and nanofibers. Microscopy studies showed that the used individualization processes lead to a unique morphology of interconnected web-like structure of hemp fibers. The nanofibers are bundles of cellulose fibers of widths ranging between 30 and 100 nm and estimated lengths of several micrometers. The chemical analysis showed that selective chemical treatments increased the α-cellulose content of hemp nanofibers from 75 to 94%. Fourier transform infrared spectroscopy (FTIR) study showed that the pectins were partially removed during the individualization treatments. X-ray analysis showed that the relative crystallinity of the studied fibers increased after each stage of chemical and mechanical treatments. It was also observed that the hemp nanofibers had an increased crystallinity of 71 from 57% of untreated hemp fibers.

Correlating morphology to dc conductivity in polymerized ionic liquids

NASA Astrophysics Data System (ADS)

Iacob, Ciprian; Matusmoto, Atsushi; Inoue, Tadashi; Runt, James

Polymerized ionic liquids (PILs) combine the attractive mechanical characteristics of polymers and unique physico-chemical properties of low molecular weight ionic liquids in the same material. PILs have shown remarkable advantages when employed in electrochemical devices such as dye-sensitized solar cells and lithium batteries, among others. Understanding their ionic transport mechanism is the key for designing highly conductive PILs. In the current study, the correlation between morphology and charge transport in two homologous series of PILs with systematic variation of the alkyl chain length and anions is investigated using broadband dielectric spectroscopy, rheology, differential scanning calorimetry and X-ray scattering. As the alkyl chain length increases, the backbone-to-backbone separation increases, and dc-conductivity consequently decreases. The cations dominate structural dynamics since they are attached to the polymer chains, while the anions are smaller and more mobile ionic species thereby controlling the ionic conductivity. Further interpretation of decoupling of dc conductivity from the segmental relaxation enabled the correlation between polymer morphology and dc conductivity. Supported by the National Science Foundation, Polymers Program.

Interface-mediated fabrication of bowl-like and deflated ballon-like hollow carbon nanospheres.

PubMed

Zhang, Haijiao; Li, Xia

2015-08-15

In our work, two kinds of hollow carbon nanospheres with controlled morphologies have been successfully prepared from low-cost and nontoxic glucose as the sole carbon precursor under neutral aqueous medium via a simple hydrothermal route. During the process, sodium dodecylbenzene sulfonate (SDBS) and triblock copolymer P123 ((EO)20(PO)70(EO)20) was skillfully selected as the structure-directing agent, respectively. SEM, TEM and AFM results revealed that the two products showed bowl-like and deflated-balloon-like morphology with uniform particle sizes, respectively. Based on the experimental observations, a possible formation mechanism was also discussed, in which the growth of the carbon nanospheres involved an interface-medicated assembly process. The present method was easy, green and mild. Apart from the unique nanostructure, the obtained bowl-like hollow carbon nanospheres exhibited excellent biocompatibility. In particular, it should be mentioned that the open window formed by the bowl-like morphology can facilitate ion transport, thus improving their performances. Copyright © 2015 Elsevier Inc. All rights reserved.

One-dimensional model for the intracranial pulse morphological analysis during hyperventilation and CO2 inhalation tests

NASA Astrophysics Data System (ADS)

Ryu, Jaiyoung; Hu, Xiao; Shadden, Shawn C.

2015-11-01

The brain's CO2 reactivity mechanism is coupled with cerebral autoregulation and other unique features of cerebral hemodynamics. We developed a one-dimensional nonlinear model of blood flow in the cerebral arteries coupled to lumped parameter (LP) networks. The LP networks incorporate cerebral autoregulation, CO2 reactivity, intracranial pressure, cerebrospinal fluid, and cortical collateral blood flow models. The model was used to evaluate hemodynamic variables (arterial deformation, blood velocity and pressure) in the cerebral vasculature during hyperventilation and CO2 inhalation test. Tests were performed for various arterial blood pressure (ABP) representing normal and hypotensive conditions. The increase of the cerebral blood flow rates agreed well with the published measurements for various ABP measurements taken during clinical CO2 reactivity tests. The changes in distal vasculature affected the reflected pulse wave energy, which caused the waveform morphological changes at the middle cerebral, common and internal carotid arteries. The pulse morphological analysis demonstrated agreement with previous clinical measurements for cerebral vasoconstriction and vasodilation.

Nesprin provides elastic properties to muscle nuclei by cooperating with spectraplakin and EB1

PubMed Central

Wang, Shuoshuo; Reuveny, Adriana

2015-01-01

Muscle nuclei are exposed to variable cytoplasmic strain produced by muscle contraction and relaxation, but their morphology remains stable. Still, the mechanism responsible for maintaining myonuclear architecture, and its importance, is currently elusive. Herein, we uncovered a unique myonuclear scaffold in Drosophila melanogaster larval muscles, exhibiting both elastic features contributed by the stretching capacity of MSP300 (nesprin) and rigidity provided by a perinuclear network of microtubules stabilized by Shot (spectraplakin) and EB1. Together, they form a flexible perinuclear shield that protects myonuclei from intrinsic or extrinsic forces. The loss of this scaffold resulted in significantly aberrant nuclear morphology and subsequently reduced levels of essential nuclear factors such as lamin A/C, lamin B, and HP1. Overall, we propose a novel mechanism for maintaining myonuclear morphology and reveal its critical link to correct levels of nuclear factors in differentiated muscle fibers. These findings may shed light on the underlying mechanism of various muscular dystrophies. PMID:26008743

Piscivory limits diversification of feeding morphology in centrarchid fishes.

PubMed

Collar, David C; O'Meara, Brian C; Wainwright, Peter C; Near, Thomas J

2009-06-01

Proximity to an adaptive peak influences a lineage's potential to diversify. We tested whether piscivory, a high quality but functionally demanding trophic strategy, represents an adaptive peak that limits morphological diversification in the teleost fish clade, Centrarchidae. We synthesized published diet data and applied a well-resolved, multilocus and time-calibrated phylogeny to reconstruct ancestral piscivory. We measured functional features of the skull and performed principal components analysis on species' values for these variables. To assess the role of piscivory on morphological diversification, we compared the fit of several models of evolution for each principal component (PC), where model parameters were allowed to vary between lineages that differed in degree of piscivory. According to the best-fitting model, two adaptive peaks influenced PC 1 evolution, one peak shared between highly and moderately piscivorous lineages and another for nonpiscivores. Brownian motion better fit PCs 2, 3, and 4, but the best Brownian models infer a slow rate of PC 2 evolution shared among all piscivores and a uniquely slow rate of PC 4 evolution in highly piscivorous lineages. These results suggest that piscivory limits feeding morphology diversification, but this effect is most severe in lineages that exhibit an extreme form of this diet.

Neomorphosis and heterochrony of skull shape in dog domestication.

PubMed

Geiger, Madeleine; Evin, Allowen; Sánchez-Villagra, Marcelo R; Gascho, Dominic; Mainini, Cornelia; Zollikofer, Christoph P E

2017-10-18

The overall similarity of the skull shape of some dog breeds with that of juvenile wolves begs the question if and how ontogenetic changes such as paedomorphosis (evolutionary juvenilisation) played a role in domestication. Here we test for changes in patterns of development and growth during dog domestication. We present the first geometric morphometric study using ontogenetic series of dog and wolf crania, and samples of dogs with relatively ancestral morphology and from different time periods. We show that patterns of juvenile-to-adult morphological change are largely similar in wolves and domestic dogs, but differ in two ways. First, dog skulls show unique (neomorphic) features already shortly after birth, and these features persist throughout postnatal ontogeny. Second, at any given age, juvenile dogs exhibit skull shapes that resemble those of consistently younger wolves, even in dog breeds that do not exhibit a 'juvenilized' morphology as adults. These patterns exemplify the complex nature of evolutionary changes during dog domestication: the cranial morphology of adult dogs cannot simply be explained as either neomorphic or paedomorphic. The key to our understanding of dog domestication may lie in a closer comparative examination of developmental phases.

Morphology-dependent water budgets and nutrient fluxes in arctic thaw ponds

USGS Publications Warehouse

Koch, Joshua C.; Gurney, Kirsty; Wipfli, Mark S.

2014-01-01

Thaw ponds on the Arctic Coastal Plain of Alaska are productive ecosystems, providing habitat and food resources for many fish and bird species. Permafrost in this region creates unique pond morphologies: deep troughs, shallow low-centred polygons (LCPs) and larger coalescent ponds. By monitoring seasonal trends in pond volume and chemistry, we evaluated whether pond morphology and size affect water temperature and desiccation, and nitrogen (N) and phosphorus (P) fluxes. Evaporation was the largest early-summer water flux in all pond types. LCPs dried quickly and displayed high early-summer nutrient concentrations and losses. Troughs consistently received solute-rich subsurface inflows, which accounted for 12 to 42 per cent of their volume and may explain higher P in the troughs. N to P ratios increased and ammonium concentrations decreased with pond volume, suggesting that P and inorganic N availability may limit ecosystem productivity in older, larger ponds. Arctic summer temperatures will likely increase in the future, which may accelerate mid-summer desiccation. Given their morphology, troughs may remain wet, become warmer and derive greater nutrient loads from their thawing banks. Overall, seasonal- to decadal-scale warming may increase ecosystem productivity in troughs relative to other Arctic Coastal Plain ponds. 

Hyoid skeleton, its related muscles, and morphological novelties in the frog Lepidobatrachus (anura, ceratophryidae).

PubMed

Fabrezi, Marissa; Lobo, Fernando

2009-11-01

Many traits of the skull of ceratophryines are related to the capture of large prey independently of aquatic or terrestrial feeding. Herein, detailed descriptions of the development of hyoid skeleton and the anatomy of muscles responsible for hyoid and tongue movements in Lepidobatrachus laevis and L. llanensis are provided and compared with those of other neobatrachians. The aquatic Lepidobatrachus has special features in its hyoid skeleton that integrates a set of derived features convergent with the conditions observed in non-neobatrachian anurans and morphological novelties (e.g., dorsal dermal hyoid ossification) that deviate from the generalized pattern found in most frogs. Further, reduction of fibers of muscles of buccal floor, reduction or loss of hyoid muscles (m. geniohyoideus rama lateralis, anterior pair of m. petrohyoideus posteriores), small tongue, and simplified tongue muscles are also morphological deviations from the pattern of terrestrial ceratophryines, and other aquatic ceratophryids (e.g., Telmatobius) that seem to be related to feeding underwater. The historical derived features shared with Chacophrys and Ceratophrys involved in megalophagy are conserved in Lepidobatrachus and morphological changes in the hyoglossal apparatus define a unique functional complex among anurans.

The evolutionary origins of Syngnathidae: pipefishes and seahorses.

PubMed

Wilson, A B; Orr, J W

2011-06-01

Despite their importance as evolutionary and ecological model systems, the phylogenetic relationships among gasterosteiforms remain poorly understood, complicating efforts to understand the evolutionary origins of the exceptional morphological and behavioural diversity of this group. The present review summarizes current knowledge on the origin and evolution of syngnathids, a gasterosteiform family with a highly developed form of male parental care, combining inferences based on morphological and molecular data with paleontological evidence documenting the evolutionary history of the group. Molecular methods have provided new tools for the study of syngnathid relationships and have played an important role in recent conservation efforts. Despite recent insights into syngnathid evolution, however, a survey of the literature reveals a strong taxonomic bias towards studies on the species-rich genera Hippocampus and Syngnathus, with a lack of data for many morphologically unique members of the family. The study of the evolutionary pressures responsible for generating the high diversity of syngnathids would benefit from a wider perspective, providing a comparative framework in which to investigate the evolution of the genetic, morphological and behavioural traits of the group as a whole. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

Experimental Detection and Visualization of the Extracellular Matrix in Macrocolony Biofilms.

PubMed

Serra, Diego O; Hengge, Regine

2017-01-01

By adopting elaborate three-dimensional morphologies that vary according to their extracellular matrix composition, macrocolony biofilms offer a unique opportunity to interrogate about the roles of specific matrix components in shaping biofilm architecture. Here, we describe two methods optimized for Escherichia coli that profit from morphology and the high level of structural organization of macrocolonies to gain insight into the production and assembly of amyloid curli and cellulose-the two major biofilm matrix elements of E. coli-in biofilms. The first method, the macrocolony morphology assay, is based on the ability of curli and cellulose-either alone or in combination-to generate specific morphological and Congo Red-staining patterns in E. coli macrocolonies, which can then be used as a direct visual readout for the production of these matrix components. The second method involves thin sectioning of macrocolonies, which along with in situ staining of amyloid curli and cellulose and microscopic imaging allows gaining fine details of the spatial arrangement of both matrix elements inside macrocolonies. Beyond their current use with E. coli and related curli and cellulose-producing Enterobacteriaceae, both the methods offer the potential to be adapted to other bacterial species.

[Morphological characteristic of Langerhans cells from the human epidermis in case of general hypothermia].

PubMed

Stefanenko, E V; Miadelets, O D; Kukhnovets, O A; Miadelets, V O

2009-01-01

The objective of this work was to study morphological changes in the Langerhans cells of epidermis and epithelium of hair follicles from subjects who died as a result of general hypothermia. A total of 105 cadaveric skin samples from subjects of either gender aged from 19 to 83 years were available for analysis. Postmortem examination 1-2 days after death was performed at the Department of Forensic Medical Examination for the Vitebsk region. Skin samples were frozen in liquid nitrogen and studied as cryostat sections. Langerhans cells were detected using the ATPase assay as described by Wachstein and Meisel and modified by Robins and Brendon. The Langerhans cells of subjects who died from general hypothermia were shown to undergo marked morphological changes. Moreover, their number significantly decreased as a result of disintegration and transformation into fine-grain material. Surviving cells lost many of their outgrowths and exhibited enhanced ATPase activity in pericarion. The Langerhans cells from dorsal and ventral skin as well as from interfollicular epidermis and the outer sheath of hair follicles underwent virtually identical changes. A unique morphological feature of the skin in those who died from general hypothermia was formation of intraepidermal, subepidermal, and dermal blisters.

A New Integrated Approach to Taxonomy: The Fusion of Molecular and Morphological Systematics with Type Material in Benthic Foraminifera

PubMed Central

Roberts, Angela; Austin, William; Evans, Katharine; Bird, Clare; Schweizer, Magali; Darling, Kate

2016-01-01

A robust and consistent taxonomy underpins the use of fossil material in palaeoenvironmental research and long-term assessment of biodiversity. This study presents a new integrated taxonomic protocol for benthic foraminifera by unequivocally reconciling the traditional taxonomic name to a specific genetic type. To implement this protocol, a fragment of the small subunit ribosomal RNA (SSU rRNA) gene is used in combination with 16 quantitative morphometric variables to fully characterise the benthic foraminiferal species concept of Elphidium williamsoni Haynes, 1973. A combination of live contemporary topotypic specimens, original type specimens and specimens of genetic outliers were utilised in this study. Through a series of multivariate statistical tests we illustrate that genetically characterised topotype specimens are morphologically congruent with both the holotype and paratype specimens of E. williamsoni Haynes, 1973. We present the first clear link between morphologically characterised type material and the unique SSU rRNA genetic type of E. williamsoni. This example provides a standard framework for the benthic foraminifera which bridges the current discontinuity between molecular and morphological lines of evidence, allowing integration with the traditional Linnaean roots of nomenclature to offer a new prospect for taxonomic stability. PMID:27388271

New protocol for synthesis of new nanomaterials with continuous 3D networks

NASA Astrophysics Data System (ADS)

Wang, Haiwang; Zhu, Ying; Wei, Xinfang; Chen, Huanhuan; Wang, Ruijie; Zhang, Dong; Song, Huaihe; Song, Shengju

2014-05-01

Nanostructured materials are attractive to researchers because of their unique optical, magnetic, thermodynamic, electrical, mechanical, and chemical properties. Controlling the morphology of nanomaterials could provide structural systems for a wide range of technologies. As a result, the development of nanofabrication techniques that are convenient and offer design flexibility is the subject of many studies. In order to progress beyond the conventional morphologies, we have turned to hydrogels, which can serve as organic templates for nanoscale objects with continuous microstructures. Transmission electron microscopy showed that the obtained nanonetwork had a continuous microstructure, which was several microns in length and width, with a cross-sectional diameter of 5-10 nm synthesized from a 35-g hexamethylenetetramine solution and a 1.5 g Zn(NO3)2 solution, and the cross-sectional diameter can be adjusted from 5 to 200 nm by controlling the concentration of the Zn(NO3)2 solution. Our results also showed that the nanostructures based on a superabsorbent polymer template could be controlled easily in terms of size and morphology by changing the concentration of the reaction solution. This protocol could be easily extended to synthesize a variety of nanostructured materials with novel morphologies.

Morphology and phase control of iron oxide polymorph nanoparticles

NASA Astrophysics Data System (ADS)

Cui, Hongtao; Wang, Li; Shi, Min; Li, Yanhong

2017-04-01

In this work, lepidocrocite (γ-FeOOH) nanobundles were prepared by a facile NH4F assisted epoxide precipitation route. The reactions between epoxide and [Fe(H2O)6]2+ promoted the hydrolysis and condensation of [Fe(H2O)6]2+, resulting in the formation of iron oxyhydroxide. After calcination of γ-FeOOH nanobundles at 400 °C, the produced α-Fe2O3 still kept the bundle morphology. Due to the unique chemistry of epoxide, the morphology and phase of iron oxide polymorph nanoparticles (goethite, akaganeite, lepidocrocite, magnetite) were well-controlled through controlling reaction conditions such as Fe2+ concentration, NH4F additive and reaction temperature. It is particularly interesting that NH4F working as phase controlling agent is able to control the phase development of iron oxyhydroxides. This phase control effect of NH4F is attributed to the promoted reaction rate of epoxide originating from the higher electronegativity of fluoride ions than chloride ions. Based on the results in this work and our other preliminary works, it is considered that this route can be used as a general strategy for controlling the morphology and phase of transition element compounds.

Form follows function: ultrastructure of different morphotypes of Physarum polycephalum

NASA Astrophysics Data System (ADS)

Oettmeier, Christina; Lee, Jonghyun; Döbereiner, Hans-Günther

2018-04-01

The multinucleate, unicellular slime mold Physarum polycephalum is a highly motile and morphologically diverse giant amoeba. Despite being brainless and lacking neurons, it exhibits ‘smart’ behavior. There is considerable interest in describing such traits and to investigate the underlying mechanochemical patterns which may hint at universal principles of behavior and decision-making. Furthermore, the slime mold’s mechanism of locomotion is unique. It resembles amoeboid movement, but differs from the locomotion of other amoebae in many ways, e.g. in their much larger size and lack of lobopodia. These two aspects, behavior and locomotion, are linked by the cytoskeleton and the overall morphology of P. polycephalum. In this paper, we present a structural analysis of different growth forms (micro-, meso- and macroplasmodia) by transmission electron microscopy (TEM), scanning electron microscopy (SEM), light microscopy, and fluorescence microscopy of F-actin. With these detailed investigations of cellular ultrastructure and morphology, we provide the basis for the analysis of, e.g. viscoelastic and rheological measurements. Our data also provide structural details for the many models that have been constructed for the understanding of locomotion. We conclude that morphological information is vital for the assessment and measurement of material properties.

Morphological Identification of Hair Recovered from Feces for Detection of Cannibalism in Eastern Chimpanzees.

PubMed

Walker, Christopher S; Walker, Kara K; Paulo, Gabo; Pusey, Anne E

2018-01-01

Chimpanzees (Pan troglodytes) are primarily frugivorous but consume a variable amount of meat from a variety of organisms, including other chimpanzees. Cannibalism is rare, usually follows lethal aggression, and does not occur following natural deaths. While chimpanzee cannibalism has been documented at multiple sites, many instances of this behavior go unrecorded. Identification of chimpanzee remains in feces, however, can provide indirect evidence of cannibalism. Hair, in particular, typically passes through the gastrointestinal tract undamaged and is commonly used for purposes of identification in wildlife forensics. Here we test the hypothesis that eastern chimpanzee (Pan troglodytes schweinfurthii) guard hair morphology can be reliably distinguished from the hairs of their most common prey species. Methods and results are presented in the context of a case study involving a suspected chimpanzee infanticide from Gombe, Tanzania. We find that chimpanzee guard hair morphology is unique among tested mammals and that the presence of abundant chimpanzee hair in feces is likely the result of cannibalism and not incidental ingestion from grooming or other means. Accordingly, morphological analysis of guard hairs from feces is a promising, cost-effective tool for the determination of cannibalistic acts in chimpanzees. © 2018 S. Karger AG, Basel.

Elaboration du Ge mesoporeux et etude de ses proprietes physico-chimiques en vue d'applications photovoltaiques

NASA Astrophysics Data System (ADS)

Tutashkonko, Sergii

Le sujet de cette these porte sur l'elaboration du nouveau nanomateriau par la gravure electrochimique bipolaire (BEE) --- le Ge mesoporeux et sur l'analyse de ses proprietes physico-chimiques en vue de son utilisation dans des applications photovoltaiques. La formation du Ge mesoporeux par gravure electrochimique a ete precedemment rapportee dans la litterature. Cependant, le verrou technologique important des procedes de fabrication existants consistait a obtenir des couches epaisses (superieure a 500 nm) du Ge mesoporeux a la morphologie parfaitement controlee. En effet, la caracterisation physico-chimique des couches minces est beaucoup plus compliquee et le nombre de leurs applications possibles est fortement limite. Nous avons developpe un modele electrochimique qui decrit les mecanismes principaux de formation des pores ce qui nous a permis de realiser des structures epaisses du Ge mesoporeux (jusqu'au 10 mum) ayant la porosite ajustable dans une large gamme de 15% a 60%. En plus, la formation des nanostructures poreuses aux morphologies variables et bien controlees est desormais devenue possible. Enfin, la maitrise de tous ces parametres a ouvert la voie extremement prometteuse vers la realisation des structures poreuses a multi-couches a base de Ge pour des nombreuses applications innovantes et multidisciplinaires grace a la flexibilite technologique actuelle atteinte. En particulier, dans le cadre de cette these, les couches du Ge mesoporeux ont ete optimisees dans le but de realiser le procede de transfert de couches minces d'une cellule solaire a triple jonctions via une couche sacrificielle en Ge poreux. Mots-cles : Germanium meso-poreux, Gravure electrochimique bipolaire, Electrochimie des semi-conducteurs, Report des couches minces, Cellule photovoltaique

Molecular Phylogeny, Recent Radiation and Evolution of Gross Morphology of the Rhubarb genus Rheum (Polygonaceae) Inferred from Chloroplast DNA trnL-F Sequences

PubMed Central

WANG, AILAN; YANG, MEIHUA; LIU, JIANQUAN

2005-01-01

• Background and Aims Rheum, a highly diversified genus with about 60 species, is mainly confined to the mountainous and desert regions of the Qinghai–Tibetan plateau and adjacent areas. This genus represents a good example of the extensive diversification of the temperate genera in the Qinghai–Tibetan plateau, in which the forces to drive diversification remain unknown. To date, the infrageneric classification of Rheum has been mainly based on morphological characters. However, it may have been subject to convergent evolution under habitat pressure, and the systematic position of some sections are unclear, especially Sect. Globulosa, which has globular inflorescences, and Sect. Nobilia, which has semi-translucent bracts. Recent palynological research has found substantial contradictions between exine patterns and the current classification of Rheum. Two specific objectives of this research were (1) to evaluate possible relationships of some ambiguous sections with a unique morphology, and (2) to examine possible occurrence of the radiative speciation with low genetic divergence across the total genus and the correlation between the extensive diversification time of Rheum and past geographical events, especially the recent large-scale uplifts of the Qinghai–Tibetan Plateau. • Methods The chloroplast DNA trnL-F region of 29 individuals representing 26 species of Rheum, belonging to seven out of eight sections, was sequenced and compared. The phylogenetic relationships were further constructed based on the sequences obtained. • Key Results Despite the highly diversified morphology, the genetic variation in this DNA fragment is relatively low. The molecular phylogeny is highly inconsistent with gross morphology, pollen exine patterns and traditional classifications, except for identifying all samples of Sect. Palmata, three species of Sect. Spiciformia and a few species of Sect. Rheum as corresponding monophyletic groups. The monotypic Sect. Globulosa showed a tentative position within the clade comprising five species of Sect. Rheum. All of the analyses revealed the paraphyly of R. nobile and R. alexandrae, the only two species of Sect. Nobilia circumscribed by the possession of large bracts. The crude calibration of lineages based on trnL-F sequence differentiation implied an extensive diversification of Rheum within approx. 7 million years. • Conclusions Based on these results, it is suggested that the rich geological and ecological diversity caused by the recent large-scale uplifts of the Qinghai–Tibetan Plateau since the late Tertiary, coupled with the oscillating climate of the Quaternary stage, might have promoted rapid speciation in small and isolated populations, as well as allowing the fixation of unique or rare morphological characters in Rheum. Such a rapid radiation, combined with introgressive hybridization and reticulate evolution, may have caused the transfer of cpDNA haplotypes between morphologically dissimilar species, and might account for the inconsistency between morphological classification and molecular phylogeny reported here. PMID:15994840

L'effet des deformations plastiques severes sur les proprietes d'hydruration du magnesium

NASA Astrophysics Data System (ADS)

Lang, Julien

Le travail de recherche effectue durant mon projet de maitrise en physique a l'Universite du Quebec a Trois-Rivieres dans les laboratoires de l'Institut de Recherche sur l'Hydrogene etait de comparer l'effet du laminage a froid de la poudre de MgH2 avec celui du broyage mecanique. Nous avons etudie cette nouvelle technique en utilisant un laminoir vertical concu specialement pour laminer de la poudre. Nous avons lamine la poudre de MgH2 5, 25, 50 et 100 fois. La comparaison de la morphologie de la poudre de MgH 2 telle que recu du manufacturier et broye mecaniquement pendant 30 minutes avec celle de la poudre laminee ete faite a l'aide d'un microscope electronique a balayage. Nous avons par la suite mesure les proprietes de sorption d'hydrogene grace un appareil PCT de type Sievert. Nous avons aussi determine la structure cristalline par diffraction de rayons X. A partir de ces resultats, nous avons constate que le nombre optimal de laminages est de cinq et a les caracteristiques d'absorption/desorption d'hydrogene similaires a un broyage mecanique de 30 minutes. Nous avons aussi utilise les courbes de cinetiques d'absorption et de desorption d'hydrogene pour calculer l'etape limitative dans les reactions de sorption des echantillons lamines. Comme cinq laminages se font en environ 10 secondes, on voit que le laminage a froid est une technique plus interessante industriellement que le broyage mecanique a cause de l'important gain en temps et en energie.

Apport de la simulation numérique à la compréhension des mécanismes d'interaction de cavités dans le cadre de la modélisation de l'endommagement ductile sous sollicitation dynamique

NASA Astrophysics Data System (ADS)

Roy, G.; Buy, F.; Llorca, F.

2002-12-01

L'étude présentée s'inscrit dans le cadre d'une démarche menant à la construction d'un modèle analytique ou semi analytique de comportement élasto-visco-plastique endommageable, applicable aux chargements rencontrés en configuration d'impact violent et générant de l'écaillage ductile. La prise en compte des effets de compressibilité et de micro inertie est essentielle pour modéliser la phase de croissance. Des simulations numériques globales de la structure et locales à l'échelle des hétérogénéités permettent d'évaluer les niveaux de sollicitations dans les zones susceptibles de s'endommager, dévaluer des critères analytiques de germination de l'endommagement et de comprendre les mécanismes d'interaction entre les défauts. Les effets micro inertiels et de compressibilité sont ainsi mis en évidence dans les phases de germination et de coalescence des micro défauts. II s'agit ici d'une illustration non exhaustive de travaux engagés au CEA Valduc sur le tantale, dans le cadre d'une thèse [10]. Un programme matériaux en partenariat CEA-CNRS sur la modélisation multi échelles du comportement de structures a également été initié dans ce contexte.

Morphological study on small molecule acceptor-based organic solar cells with efficiencies beyond 7% (Presentation Recording)

NASA Astrophysics Data System (ADS)

Ma, Wei; Yan, He

2015-10-01

Despite the essential role of fullerenes in achieving best-performance organic solar cells (OSCs), fullerene acceptors have several drawbacks including poor light absorption, high-cost production and purification. For this reason, small molecule acceptor (SMA)-based OSCs have attracted much attention due to the easy tunability of electronic and optical properties of SMA materials. In this study, polymers with temperature dependent aggregation behaviors are combined with various small molecule acceptor materials, which lead to impressive power conversion efficiencies of up to 7.3%. The morphological and aggregation properties of the polymer:small molecule blends are studied in details. It is found that the temperature-dependent aggregation behavior of polymers allows for the processing of the polymer solutions at moderately elevated temperature, and more importantly, controlled aggregation and strong crystallization of the polymer during the film cooling and drying process. This results in a well-controlled and near-ideal polymer:small molecule morphology that is controlled by polymer aggregation during warm casting and thus insensitive to the choice of small molecules. As a result, several cases of highly efficient (PCE between 6-7.3%) SMA OSCs are achieved. The second part of this presentation will describe the morphology of a new small molecule acceptor with a unique 3D structure. The relationship between molecular structure and morphology is revealed.

Self-assembly behaviours of peptide-drug conjugates: influence of multiple factors on aggregate morphology and potential self-assembly mechanism

NASA Astrophysics Data System (ADS)

Fan, Qin; Ji, Yujie; Wang, Jingjing; Wu, Li; Li, Weidong; Chen, Rui; Chen, Zhipeng

2018-04-01

Peptide-drug conjugates (PDCs) as self-assembly prodrugs have the unique and specific features to build one-component nanomedicines. Supramolecular structure based on PDCs could form various morphologies ranging from nanotube, nanofibre, nanobelt to hydrogel. However, the assembly process of PDCs is too complex to predict or control. Herein, we investigated the effects of extrinsic factors on assembly morphology and the possible formation of nanostructures based on PDCs. To this end, we designed a PDC consisting of hydrophobic drug (S)-ketoprofen (Ket) and valine-glutamic acid dimeric repeats peptide (L-VEVE) to study their assembly behaviour. Our results showed that the critical assembly concentration of Ket-L-VEVE was 0.32 mM in water to form various nanostructures which experienced from micelle, nanorod, nanofibre to nanoribbon. The morphology was influenced by multiple factors including molecular design, assembly time, pH and hydrogen bond inhibitor. On the basis of experimental results, we speculated the possible assembly mechanism of Ket-L-VEVE. The π-π stacking interaction between Ket molecules could serve as an anchor, and hydrogen bonded-induced β-sheets and hydrophilic/hydrophobic balance between L-VEVE peptide play structure-directing role in forming filament-like or nanoribbon morphology. This work provides a new sight to rationally design and precisely control the nanostructure of PDCs based on aromatic fragment.

Linking macroscopic with microscopic neuroanatomy using synthetic neuronal populations.

PubMed

Schneider, Calvin J; Cuntz, Hermann; Soltesz, Ivan

2014-10-01

Dendritic morphology has been shown to have a dramatic impact on neuronal function. However, population features such as the inherent variability in dendritic morphology between cells belonging to the same neuronal type are often overlooked when studying computation in neural networks. While detailed models for morphology and electrophysiology exist for many types of single neurons, the role of detailed single cell morphology in the population has not been studied quantitatively or computationally. Here we use the structural context of the neural tissue in which dendritic trees exist to drive their generation in silico. We synthesize the entire population of dentate gyrus granule cells, the most numerous cell type in the hippocampus, by growing their dendritic trees within their characteristic dendritic fields bounded by the realistic structural context of (1) the granule cell layer that contains all somata and (2) the molecular layer that contains the dendritic forest. This process enables branching statistics to be linked to larger scale neuroanatomical features. We find large differences in dendritic total length and individual path length measures as a function of location in the dentate gyrus and of somatic depth in the granule cell layer. We also predict the number of unique granule cell dendrites invading a given volume in the molecular layer. This work enables the complete population-level study of morphological properties and provides a framework to develop complex and realistic neural network models.

Linking Macroscopic with Microscopic Neuroanatomy Using Synthetic Neuronal Populations

PubMed Central

Schneider, Calvin J.; Cuntz, Hermann; Soltesz, Ivan

2014-01-01

Dendritic morphology has been shown to have a dramatic impact on neuronal function. However, population features such as the inherent variability in dendritic morphology between cells belonging to the same neuronal type are often overlooked when studying computation in neural networks. While detailed models for morphology and electrophysiology exist for many types of single neurons, the role of detailed single cell morphology in the population has not been studied quantitatively or computationally. Here we use the structural context of the neural tissue in which dendritic trees exist to drive their generation in silico. We synthesize the entire population of dentate gyrus granule cells, the most numerous cell type in the hippocampus, by growing their dendritic trees within their characteristic dendritic fields bounded by the realistic structural context of (1) the granule cell layer that contains all somata and (2) the molecular layer that contains the dendritic forest. This process enables branching statistics to be linked to larger scale neuroanatomical features. We find large differences in dendritic total length and individual path length measures as a function of location in the dentate gyrus and of somatic depth in the granule cell layer. We also predict the number of unique granule cell dendrites invading a given volume in the molecular layer. This work enables the complete population-level study of morphological properties and provides a framework to develop complex and realistic neural network models. PMID:25340814

Self-assembly behaviours of peptide-drug conjugates: influence of multiple factors on aggregate morphology and potential self-assembly mechanism.

PubMed

Fan, Qin; Ji, Yujie; Wang, Jingjing; Wu, Li; Li, Weidong; Chen, Rui; Chen, Zhipeng

2018-04-01

Peptide-drug conjugates (PDCs) as self-assembly prodrugs have the unique and specific features to build one-component nanomedicines. Supramolecular structure based on PDCs could form various morphologies ranging from nanotube, nanofibre, nanobelt to hydrogel. However, the assembly process of PDCs is too complex to predict or control. Herein, we investigated the effects of extrinsic factors on assembly morphology and the possible formation of nanostructures based on PDCs. To this end, we designed a PDC consisting of hydrophobic drug ( S )-ketoprofen (Ket) and valine-glutamic acid dimeric repeats peptide (L-VEVE) to study their assembly behaviour. Our results showed that the critical assembly concentration of Ket-L-VEVE was 0.32 mM in water to form various nanostructures which experienced from micelle, nanorod, nanofibre to nanoribbon. The morphology was influenced by multiple factors including molecular design, assembly time, pH and hydrogen bond inhibitor. On the basis of experimental results, we speculated the possible assembly mechanism of Ket-L-VEVE. The π-π stacking interaction between Ket molecules could serve as an anchor, and hydrogen bonded-induced β-sheets and hydrophilic/hydrophobic balance between L-VEVE peptide play structure-directing role in forming filament-like or nanoribbon morphology. This work provides a new sight to rationally design and precisely control the nanostructure of PDCs based on aromatic fragment.

Hippocampus-based contextual memory alters the morphological characteristics of astrocytes in the dentate gyrus.

PubMed

Choi, Moonseok; Ahn, Sangzin; Yang, Eun-Jeong; Kim, Hyunju; Chong, Young Hae; Kim, Hye-Sun

2016-07-26

Astrocytes have been reported to exist in two states, the resting and the reactive states. Morphological changes in the reactive state of astrocytes include an increase in thickness and number of processes, and an increase in the size of the cell body. Molecular changes also occur, such as an increase in the expression of glial fibrillary acidic protein (GFAP). However, the morphological and molecular changes during the process of learning and memory have not been elucidated. In the current study, we subjected Fvb/n mice to contextual fear conditioning, and checked for morphological and molecular changes in astrocytes. 1 h after fear conditioning, type II and type III astrocytes exhibited a unique status with an increased number of processes and decreased GFAP expression which differed from the typical resting or reactive state. In addition, the protein level of excitatory excitatory amino acid transporter 2 (EAAT2) was increased 1 h to 24 h after contextual fear conditioning while EAAT1 did not show any alterations. Connexin 43 (Cx43) protein was found to be increased at 24 h after fear conditioning. These data suggest that hippocampus-based contextual memory process induces changes in the status of astrocytes towards a novel status different from typical resting or reactive states. These morphological and molecular changes may be in line with functional changes.

Extracting hurricane eye morphology from spaceborne SAR images using morphological analysis

NASA Astrophysics Data System (ADS)

Lee, Isabella K.; Shamsoddini, Ali; Li, Xiaofeng; Trinder, John C.; Li, Zeyu

2016-07-01

Hurricanes are among the most destructive global natural disasters. Thus recognizing and extracting their morphology is important for understanding their dynamics. Conventional optical sensors, due to cloud cover associated with hurricanes, cannot reveal the intense air-sea interaction occurring at the sea surface. In contrast, the unique capabilities of spaceborne synthetic aperture radar (SAR) data for cloud penetration, and its backscattering signal characteristics enable the extraction of the sea surface roughness. Therefore, SAR images enable the measurement of the size and shape of hurricane eyes, which reveal their evolution and strength. In this study, using six SAR hurricane images, we have developed a mathematical morphology method for automatically extracting the hurricane eyes from C-band SAR data. Skeleton pruning based on discrete skeleton evolution (DSE) was used to ensure global and local preservation of the hurricane eye shape. This distance weighted algorithm applied in a hierarchical structure for extraction of the edges of the hurricane eyes, can effectively avoid segmentation errors by reducing redundant skeletons attributed to speckle noise along the edges of the hurricane eye. As a consequence, the skeleton pruning has been accomplished without deficiencies in the key hurricane eye skeletons. A morphology-based analyses of the subsequent reconstructions of the hurricane eyes shows a high degree of agreement with the hurricane eye areas derived from reference data based on NOAA manual work.

Management implications of the ecology of free-roaming horses in semiarid ecosystems of the western United States

USGS Publications Warehouse

Beever, Erik

2003-01-01

Compared to other ungulates of North America, free-roaming horses (Equus caballus) possess a unique evolutionary history that has given rise to a distinct suite of behavioral, morphological, and physiological traits. Because of their unique combination of cecal digestion, an elongate head with flexible lips, and non-uniform use of the landscape, horses represent a unique disturbance agent in semi-arid ecosystems of the western United States. Consequently, it is inappropriate to assume that influences of horses on the structure, composition, function, and pattern of arid and semi-arid ecosystems will mirror influences of cattle or other artiodactyls. Although management areas for free-roaming horses occupy 18.6 million ha of land across western North America, we know relatively little about how western ecosystems and their components have responded to this uniquely managed ungulate. I draw on my research of horse habitats in the western Great Basin (U.S.A.) to examine predictions of horses' unique influence, and advocate for continued research to refine our understanding of synecological relationships among horses and diverse ecosystem components in arid and semi-arid regions. 

Shared and unique patterns of phenotypic diversification along a stream gradient in two congeneric species

NASA Astrophysics Data System (ADS)

Jourdan, Jonas; Krause, Sarah T.; Lazar, V. Max; Zimmer, Claudia; Sommer-Trembo, Carolin; Arias-Rodriguez, Lenin; Klaus, Sebastian; Riesch, Rüdiger; Plath, Martin

2016-12-01

Stream ecosystems show gradual variation of various selection factors, which can result in a zonation of species distributions and gradient evolution of morphological and life-history traits within species. Identifying the selective agents underlying such phenotypic evolution is challenging as different species could show shared and/or unique (species-specific) responses to components of the river gradient. We studied a stream gradient inhabited by two mosquitofishes (genus Gambusia) in the Río Grijalva basin in southern Mexico and found a patchy distribution pattern of both congeners along a stretch of 100 km, whereby one species was usually dominant at a given site. We uncovered both shared and unique patterns of diversification: some components of the stream gradient, including differences in piscine predation pressure, drove shared patterns of phenotypic divergence, especially in females. Other components of the gradient, particularly abiotic factors (max. annual temperature and temperature range) resulted in unique patterns of divergence, especially in males. Our study highlights the complexity of selective regimes in stream ecosystems. It exemplifies that even closely related, congeneric species can respond in unique ways to the same components of the river gradient and shows how both sexes can exhibit quite different patterns of divergence in multivariate phenotypic character suites.

Shared and unique patterns of phenotypic diversification along a stream gradient in two congeneric species

PubMed Central

Jourdan, Jonas; Krause, Sarah T.; Lazar, V. Max; Zimmer, Claudia; Sommer-Trembo, Carolin; Arias-Rodriguez, Lenin; Klaus, Sebastian; Riesch, Rüdiger; Plath, Martin

2016-01-01

Stream ecosystems show gradual variation of various selection factors, which can result in a zonation of species distributions and gradient evolution of morphological and life-history traits within species. Identifying the selective agents underlying such phenotypic evolution is challenging as different species could show shared and/or unique (species-specific) responses to components of the river gradient. We studied a stream gradient inhabited by two mosquitofishes (genus Gambusia) in the Río Grijalva basin in southern Mexico and found a patchy distribution pattern of both congeners along a stretch of 100 km, whereby one species was usually dominant at a given site. We uncovered both shared and unique patterns of diversification: some components of the stream gradient, including differences in piscine predation pressure, drove shared patterns of phenotypic divergence, especially in females. Other components of the gradient, particularly abiotic factors (max. annual temperature and temperature range) resulted in unique patterns of divergence, especially in males. Our study highlights the complexity of selective regimes in stream ecosystems. It exemplifies that even closely related, congeneric species can respond in unique ways to the same components of the river gradient and shows how both sexes can exhibit quite different patterns of divergence in multivariate phenotypic character suites. PMID:27982114

Shared and unique patterns of phenotypic diversification along a stream gradient in two congeneric species.

PubMed

Jourdan, Jonas; Krause, Sarah T; Lazar, V Max; Zimmer, Claudia; Sommer-Trembo, Carolin; Arias-Rodriguez, Lenin; Klaus, Sebastian; Riesch, Rüdiger; Plath, Martin

2016-12-16

Stream ecosystems show gradual variation of various selection factors, which can result in a zonation of species distributions and gradient evolution of morphological and life-history traits within species. Identifying the selective agents underlying such phenotypic evolution is challenging as different species could show shared and/or unique (species-specific) responses to components of the river gradient. We studied a stream gradient inhabited by two mosquitofishes (genus Gambusia) in the Río Grijalva basin in southern Mexico and found a patchy distribution pattern of both congeners along a stretch of 100 km, whereby one species was usually dominant at a given site. We uncovered both shared and unique patterns of diversification: some components of the stream gradient, including differences in piscine predation pressure, drove shared patterns of phenotypic divergence, especially in females. Other components of the gradient, particularly abiotic factors (max. annual temperature and temperature range) resulted in unique patterns of divergence, especially in males. Our study highlights the complexity of selective regimes in stream ecosystems. It exemplifies that even closely related, congeneric species can respond in unique ways to the same components of the river gradient and shows how both sexes can exhibit quite different patterns of divergence in multivariate phenotypic character suites.

Glucose, Lactate, and Shuttling of Metabolites in Vertebrate Retinas

PubMed Central

Hurley, James B.; Lindsay, Kenneth J.; Du, Jianhai

2016-01-01

The vertebrate retina has specific functions and structures that give it a unique set of constraints on the way in which it can produce and use metabolic energy. The retina’s response to illumination influences its energy requirements, and the retina’s laminated structure influences the extent to which neurons and glia can access metabolic fuels. There are fundamental differences between energy metabolism in retina and that in brain. The retina relies on aerobic glycolysis much more than the brain does, and morphological differences between retina and brain limit the types of metabolic relationships that are possible between neurons and glia. This Mini-Review summarizes the unique metabolic features of the retina with a focus on the role of lactate shuttling. PMID:25801286

Mechanical properties of biological specimens explored by atomic force microscopy

NASA Astrophysics Data System (ADS)

Kasas, S.; Longo, G.; Dietler, G.

2013-04-01

The atomic force microscope is a widely used surface scanning apparatus capable of reconstructing at a nanometric scale resolution the 3D morphology of biological samples. Due to its unique sensitivity, it is now increasingly used as a force sensor, to characterize the mechanical properties of specimens with a similar lateral resolution. This unique capability has produced, in the last years, a vast increase in the number of groups that have exploited the versatility and sensitivity of the instrument to explore the nanomechanics of various samples in the fields of biology, microbiology and medicine. In this review we outline the state of the art in this field, reporting the most interesting recent works involving the exploration of the nanomechanical properties of various biological samples.

Merging mythology and morphology: the multifaceted lifestyle of Proteus mirabilis.

PubMed

Armbruster, Chelsie E; Mobley, Harry L T

2012-11-01

Proteus mirabilis, named for the Greek god who changed shape to avoid capture, has fascinated microbiologists for more than a century with its unique swarming differentiation, Dienes line formation and potent urease activity. Transcriptome profiling during both host infection and swarming motility, coupled with the availability of the complete genome sequence for P. mirabilis, has revealed the occurrence of interbacterial competition and killing through a type VI secretion system, and the reciprocal regulation of adhesion and motility, as well as the intimate connections between metabolism, swarming and virulence. This Review addresses some of the unique and recently described aspects of P. mirabilis biology and pathogenesis, and emphasizes the potential role of this bacterium in single-species and polymicrobial urinary tract infections.

Merging mythology and morphology: the multifaceted lifestyle of Proteus mirabilis

PubMed Central

Armbruster, Chelsie E.; Mobley, Harry L. T.

2013-01-01

Proteus mirabilis, named for the Greek god who changed shape to avoid capture, has fascinated microbiologists for more than a century with its unique swarming differentiation, Dienes line formation and potent urease activity. Transcriptome profiling during both host infection and swarming motility, coupled with the availability of the complete genome sequence for P. mirabilis, has revealed the occurrence of interbacterial competition and killing through a type VI secretion system, and the reciprocal regulation of adhesion and motility, as well as the intimate connections between metabolism, swarming and virulence. This Review addresses some of the unique and recently described aspects of P. mirabilis biology and pathogenesis, and emphasizes the potential role of this bacterium in single- species and polymicrobial urinary tract infections. PMID:23042564

Micromechanics of Sea Urchin spines.

PubMed

Tsafnat, Naomi; Fitz Gerald, John D; Le, Hai N; Stachurski, Zbigniew H

2012-01-01

The endoskeletal structure of the Sea Urchin, Centrostephanus rodgersii, has numerous long spines whose known functions include locomotion, sensing, and protection against predators. These spines have a remarkable internal microstructure and are made of single-crystal calcite. A finite-element model of the spine's unique porous structure, based on micro-computed tomography (microCT) and incorporating anisotropic material properties, was developed to study its response to mechanical loading. Simulations show that high stress concentrations occur at certain points in the spine's architecture; brittle cracking would likely initiate in these regions. These analyses demonstrate that the organization of single-crystal calcite in the unique, intricate morphology of the sea urchin spine results in a strong, stiff and lightweight structure that enhances its strength despite the brittleness of its constituent material.

Linking stream ecology with morphological variability in a native freshwater fish from semi-arid Australia

PubMed Central

Lostrom, Samantha; Evans, Jonathan P; Grierson, Pauline F; Collin, Shaun P; Davies, Peter M; Kelley, Jennifer L

2015-01-01

Environmental variation is a potent force affecting phenotypic expression. While freshwater fishes have provided a compelling example of the link between the environment and phenotypic diversity, few studies have been conducted with arid-zone fishes, particularly those that occur in geographically isolated regions where species typically inhabit intermittent and ephemeral creeks. We investigated morphological variation of a freshwater fish (the western rainbowfish, Melanotaenia australis) inhabiting creeks in the Pilbara region of northwest Australia to determine whether body shape variation correlated with local environmental characteristics, including water velocity, habitat complexity, predator presence, and food availability. We expected that the geographic isolation of creeks within this arid region would result in habitat-specific morphological specializations. We used landmark-based geometric morphometrics to quantify the level of morphological variability in fish captured from 14 locations within three distinct subcatchments of a major river system. Western rainbowfish exhibited a range of morphologies, with variation in body depth accounting for a significant proportion (>42%) of the total variance in shape. Sexual dimorphism was also apparent, with males displaying deeper bodies than females. While the measured local habitat characteristics explained little of the observed morphological variation, fish displayed significant morphological differentiation at the level of the subcatchment. Local adaptation may partly explain the geographic patterns of body shape variation, but fine-scale genetic studies are required to disentangle the effects of genetic differentiation from environmentally determined phenotypic plasticity in body shape. Developing a better understanding of environment–phenotype relationships in species from arid regions will provide important insights into ecological and evolutionary processes in these unique and understudied habitats. PMID:26380663

Influence of Zwitterions on Thermomechanical Properties and Morphology of Acrylic Copolymers: Implications for Electroactive Applications

DTIC Science & Technology

2011-09-30

transducers from branched sulfonated polysulfones.7 The mechanical strength of the membranes drastically decreased upon introduction of ionic liquids to... liquids ,8 and zwitterionomers maintained mechanical strengths upon swelling with 10 wt % ionic liquid . Zwitterions are chargedmolecules that contain...water purification5 to biotechnology.6 A unique combination of physical properties of ionomeric membranes is the ionic con- ductivity of lowmolar mass

Weak localization of electromagnetic waves and opposition phenomena exhibited by high-albedo atmosphereless solar system objects.

PubMed

Mishchenko, Michael I; Rosenbush, Vera K; Kiselev, Nikolai N

2006-06-20

The totality of new and previous optical observations of a class of high-albedo solar system objects at small phase angles reveals a unique combination of extremely narrow brightness and polarization features centered at exactly the opposition. The specific morphological parameters of these features provide an almost unequivocal evidence that they are caused by the renowned effect of coherent backscattering.

Anuran radiations and the evolution of tadpole morphospace

PubMed Central

Roelants, Kim; Haas, Alexander; Bossuyt, Franky

2011-01-01

Anurans (frogs and toads) are unique among land vertebrates in possessing a free-living larval stage that, parallel to adult frogs, diversified into an impressive range of ecomorphs. The tempo and mode at which tadpole morphology evolved through anuran history as well as its relationship to lineage diversification remain elusive. We used a molecular phylogenetic framework to examine patterns of morphological evolution in tadpoles in light of observed episodes of accelerated lineage diversification. Our reconstructions show that the expansion of tadpole morphospace during the basal anuran radiation in the Triassic/Early Jurassic was unparalleled by the basal neobatrachian radiation in the Late Jurassic/Early Cretaceous or any subsequent radiation in the Late Cretaceous/Early Tertiary. Comparative analyses of radiation episodes indicate that the slowdown of morphospace expansion was caused not only by a drop in evolutionary rate after the basal anuran radiation but also by an overall increase in homoplasy in the characters that did evolve during later radiations. The overlapping sets of evolving characters among more recent radiations may have enhanced tadpole diversity by creating unique combinations of homoplastic traits, but the lack of innovative character changes prevented the exploration of fundamental regions in morphospace. These complex patterns transcend the four traditionally recognized tadpole morphotypes and apply to most tissue types and body parts. PMID:21555583

Revised systematics of Holospora-like bacteria and characterization of "Candidatus Gortzia infectiva", a novel macronuclear symbiont of Paramecium jenningsi.

PubMed

Boscaro, Vittorio; Fokin, Sergei I; Schrallhammer, Martina; Schweikert, Michael; Petroni, Giulio

2013-01-01

The genus Holospora (Rickettsiales) includes highly infectious nuclear symbionts of the ciliate Paramecium with unique morphology and life cycle. To date, nine species have been described, but a molecular characterization is lacking for most of them. In this study, we have characterized a novel Holospora-like bacterium (HLB) living in the macronuclei of a Paramecium jenningsi population. This bacterium was morphologically and ultrastructurally investigated in detail, and its life cycle and infection capabilities were described. We also obtained its 16S rRNA gene sequence and developed a specific probe for fluorescence in situ hybridization experiments. A new taxon, "Candidatus Gortzia infectiva", was established for this HLB according to its unique characteristics and the relatively low DNA sequence similarities shared with other bacteria. The phylogeny of the order Rickettsiales based on 16S rRNA gene sequences has been inferred, adding to the available data the sequence of the novel bacterium and those of two Holospora species (Holospora obtusa and Holospora undulata) characterized for the purpose. Our phylogenetic analysis provided molecular support for the monophyly of HLBs and showed a possible pattern of evolution for some of their features. We suggested to classify inside the family Holosporaceae only HLBs, excluding other more distantly related and phenotypically different Paramecium endosymbionts.

Deposition of collagen type I onto skeletal endothelium reveals a new role for blood vessels in regulating bone morphology

PubMed Central

Ben Shoham, Adi; Rot, Chagai; Stern, Tomer; Krief, Sharon; Akiva, Anat; Dadosh, Tali; Sabany, Helena; Lu, Yinhui; Kadler, Karl E.

2016-01-01

Recently, blood vessels have been implicated in the morphogenesis of various organs. The vasculature is also known to be essential for endochondral bone development, yet the underlying mechanism has remained elusive. We show that a unique composition of blood vessels facilitates the role of the endothelium in bone mineralization and morphogenesis. Immunostaining and electron microscopy showed that the endothelium in developing bones lacks basement membrane, which normally isolates the blood vessel from its surroundings. Further analysis revealed the presence of collagen type I on the endothelial wall of these vessels. Because collagen type I is the main component of the osteoid, we hypothesized that the bone vasculature guides the formation of the collagenous template and consequently of the mature bone. Indeed, some of the bone vessels were found to undergo mineralization. Moreover, the vascular pattern at each embryonic stage prefigured the mineral distribution pattern observed one day later. Finally, perturbation of vascular patterning by overexpressing Vegf in osteoblasts resulted in abnormal bone morphology, supporting a role for blood vessels in bone morphogenesis. These data reveal the unique composition of the endothelium in developing bones and indicate that vascular patterning plays a role in determining bone shape by forming a template for deposition of bone matrix. PMID:27621060

EST-SSR marker revealed effective over biochemical and morphological scepticism towards identification of specific turmeric (Curcuma longa L.) cultivars.

PubMed

Sahoo, Ambika; Jena, Sudipta; Kar, Basudeba; Sahoo, Suprava; Ray, Asit; Singh, Subhashree; Joshi, Raj Kumar; Acharya, Laxmikanta; Nayak, Sanghamitra

2017-05-01

Turmeric (Curcuma longa L., family Zingiberaceae) is one of the most economically important plants for its use in food, medicine, and cosmetic industries. Cultivar identification is a major constraint in turmeric, owing to high degree of morphological similarity that in turn, affects its commercialization. The present study addresses this constraint, using EST-SSR marker based, molecular identification of 8 elite cultivars and 88 accessions in turmeric. Fifty EST-SSR primers were screened against eight cultivars of turmeric (Suroma, Roma, Lakadong, Megha, Alleppey Supreme, Kedaram, Pratibha, and Suvarna); out of which 11 primers showed polymorphic banding pattern. The polymorphic information content (PIC) of these primers ranged from 0.13 to 0.48. However, only three SSR loci (CSSR 14, CSSR 15, and CSSR 18) gave reproducible unique banding pattern clearly distinguishing the cultivars 'Lakadong' and 'Suvarna' from other cultivars tested. These three unique SSR markers also proved to be effective in identification of 'Lakadong' cultivars when analysed with 88 accessions of turmeric collected from different agro-climatic regions. Furthermore, two identified cultivars (Lakadong and Suvarna) could also be precisely differentiated when analysed and based on phylogenetic tree, with other 94 genotypes of turmeric. The novel SSR markers can be used for identification and authentication of two commercially important turmeric cultivars 'Lakadong' and 'Suvarna'.

Letting the ‘cat’ out of the bag: pouch young development of the extinct Tasmanian tiger revealed by X-ray computed tomography

PubMed Central

Spoutil, Frantisek; Prochazka, Jan; Black, Jay R.; Medlock, Kathryn; Paddle, Robert N.; Knitlova, Marketa; Hipsley, Christy A.

2018-01-01

The Tasmanian tiger or thylacine (Thylacinus cynocephalus) was an iconic Australian marsupial predator that was hunted to extinction in the early 1900s. Despite sharing striking similarities with canids, they failed to evolve many of the specialized anatomical features that characterize carnivorous placental mammals. These evolutionary limitations are thought to arise from functional constraints associated with the marsupial mode of reproduction, in which otherwise highly altricial young use their well-developed forelimbs to climb to the pouch and mouth to suckle. Here we present the first three-dimensional digital developmental series of the thylacine throughout its pouch life using X-ray computed tomography on all known ethanol-preserved specimens. Based on detailed skeletal measurements, we refine the species growth curve to improve age estimates for the individuals. Comparison of allometric growth trends in the appendicular skeleton (fore- and hindlimbs) with that of other placental and marsupial mammals revealed that despite their unique adult morphologies, thylacines retained a generalized early marsupial ontogeny. Our approach also revealed mislabelled specimens that possessed large epipubic bones (vestigial in thylacine) and differing vertebral numbers. All of our generated CT models are publicly available, preserving their developmental morphology and providing a novel digital resource for future studies of this unique marsupial. PMID:29515893

Biomimetic surface structuring using cylindrical vector femtosecond laser beams

PubMed Central

Skoulas, Evangelos; Manousaki, Alexandra; Fotakis, Costas; Stratakis, Emmanuel

2017-01-01

We report on a new, single-step and scalable method to fabricate highly ordered, multi-directional and complex surface structures that mimic the unique morphological features of certain species found in nature. Biomimetic surface structuring was realized by exploiting the unique and versatile angular profile and the electric field symmetry of cylindrical vector (CV) femtosecond (fs) laser beams. It is shown that, highly controllable, periodic structures exhibiting sizes at nano-, micro- and dual- micro/nano scales can be directly written on Ni upon line and large area scanning with radial and azimuthal polarization beams. Depending on the irradiation conditions, new complex multi-directional nanostructures, inspired by the Shark’s skin morphology, as well as superhydrophobic dual-scale structures mimicking the Lotus’ leaf water repellent properties can be attained. It is concluded that the versatility and features variations of structures formed is by far superior to those obtained via laser processing with linearly polarized beams. More important, by exploiting the capabilities offered by fs CV fields, the present technique can be further extended to fabricate even more complex and unconventional structures. We believe that our approach provides a new concept in laser materials processing, which can be further exploited for expanding the breadth and novelty of applications. PMID:28327611

Evolution of vertebrate mechanosensory hair cells and inner ears: toward identifying stimuli that select mutation driven altered morphologies

PubMed Central

Fritzsch, Bernd; Straka, Hans

2014-01-01

Among the major distance senses of vertebrates, the ear is unique in its complex morphological changes during evolution. Conceivably, these changes enable the ear to adapt toward sensing various physically well-characterized stimuli. This review develops a scenario that integrates sensory cell with organ evolution. We propose that molecular and cellular evolution of the vertebrate hair cells occurred prior to the formation of the vertebrate ear. We previously proposed that the genes driving hair cell differentiation, were aggregated in the otic region through developmental re-patterning that generated a unique vertebrate embryonic structure, the otic placode. In agreement with the presence of graviceptive receptors in many vertebrate outgroups, it is likely that the vertebrate ear originally functioned as a simple gravity-sensing organ. Based on the rare occurrence of angular acceleration receptors in vertebrate outgroups, we further propose that the canal system evolved with a more sophisticated ear morphogenesis. This evolving morphogenesis obviously turned the initial otocyst into a complex set of canals and recesses, harboring multiple sensory epithelia each adapted to the acquisition of a specific aspect of a given physical stimulus. As support for this evolutionary progression, we provide several details of the molecular basis of ear development. PMID:24281353

Diversity and evolution of the Confuciusornithidae: Evidence from a new 131-million-year-old specimen from the Huajiying Formation in NE China

NASA Astrophysics Data System (ADS)

Navalón, Guillermo; Meng, Qingjin; Marugán-Lobón, Jesús; Zhang, Yuguang; Wang, Baopeng; Xing, Hai; Liu, Di; Chiappe, Luis M.

2018-02-01

The Huajiying Formation contains the earliest deposits of the Jehol Biota, representing the world's second oldest avifauna. This avifauna includes the early confuciusornithid Eoconfuciusornis zhengi, the oldest occurrence of this clade and one of the earliest divergences of pygostylian birds. Although E. zhengi shows unique traits, the holotype's immature age makes comparisons with the better known Confuciusornis sanctus problematic. As a result, the taxonomic validity of E. zhengi is controversial. We describe a small, osteologically adult confuciusornithid from the same deposits as E. zhengi. The new fossil is most similar to E. zhengi but also shares traits with the stratigraphically younger Confuciusornis. The humerus of the new fossil is straighter and more slender, and bears a less dorsally-developed deltopectoral crest compared with similarly-sized and smaller specimens of Confuciusornis. The morphology of the humerus is intermediate between E. zhengi and Confuciusornis and its proximal portion is pierced by a small deltopectoral foramen, absent in the holotype of E. zhengi. However, this foramen is much smaller than in any other confuciusornithid. Shape analyses (geometric morphometrics) of the humerus of confuciusornithids of different ages and representatives of other basal avians and closely-related non-avian theropods supports our observations and indicate that the humeral differences between the holotype of E. zhengi and the new specimen are not easily explained as ontogenetic variation within a single species. However, the limited number of early confuciursornithids does not allow us to confidently interpret such differences as interspecific. Nonetheless, these analyses support the morphological distinctiveness of the early confuciusornithids from the Huajiying Formation and suggest a stepwise acquisition of the unique humeral morphology of Confuciusornithidae.

The relationship between 3D morphology of optic disc and spatial patterns of visual field loss in glaucoma

NASA Astrophysics Data System (ADS)

Wang, Mengyu; Wang, Hui; Baniasadi, Neda; Elze, Tobias

2017-02-01

Purpose: Optic disc tilt defined over 3D optic disc morphology has been shown to be associated with the location of initial glaucomatous damages. In this work, we study the impact of optic cup depth (OCD) on spatial patterns of visual field loss in glaucoma. Methods: Pairs of reliable Cirrus OCT scans around optic disc and Humphrey visual fields of glaucoma patients without visually significant cataract and age-related macular degeneration were selected. The most recent visit of a randomly selected eye of each patient was chosen. The OCD was automatically calculated on the superior-inferior cross sectional image passing through the optic disc center. The correlations between the mean pattern deviation (PD) of each sector in glaucoma hemifield test (GHT) and Garway-Heath scheme and OCD were evaluated for all severities glaucoma and mild glaucoma (mean deviation >= -5 dB), respectively. Results: 424 eyes of 424 patients passed the data reliability criteria with 346 mild glaucoma patients. For all severities glaucoma, there was no significant correlation between the mean sector PD and OCD. For mild glaucoma, OCD was uniquely correlated to the mean PD of the inferior pericentral sector (r=-0.18, p=0.01) in GHT, which was independent of mean deviation and retinal nerve fiber layer thickness (p<0.001 for both). Conclusion: OCD was uniquely correlated to the vision loss of the inferior pericentral sector in GHT and Garway- Health scheme for mild glaucoma. Future advancement of OCT imaging techniques may provide better clinical diagnosis for early glaucoma by focusing on 3D morphological variation of the optic disc.

Evaluation d'une approche pedagogique respectant les facons d'apprendre des filles en sciences et en TIC en 9e annee au Nouveau-Brunswick

NASA Astrophysics Data System (ADS)

Lirette-Pitre, Nicole T.

2009-07-01

La reussite scolaire des filles les amene de plus en plus a poursuivre une formation postsecondaire et a exercer des professions qui demandent un haut niveau de connaissances et d'expertise scientifique. Toutefois, les filles demeurent toujours tres peu nombreuses a envisager une carriere en sciences (chimie et physique), en ingenierie ou en TIC (technologie d'information et de la communication), soit une carriere reliee a la nouvelle economie. Pour plusieurs filles, les sciences et les TIC ne sont pas des matieres scolaires qu'elles trouvent interessantes meme si elles y reussissent tres bien. Ces filles admettent que leurs experiences d'apprentissage en sciences et en TIC ne leur ont pas permis de developper un interet ni de se sentir confiante en leurs habiletes a reussir dans ces matieres. Par consequent, peu de filles choisissent de poursuivre leurs etudes postsecondaires dans ces disciplines. La theorie sociocognitive du choix carriere a ete choisie comme modele theorique pour mieux comprendre quelles variables entrent en jeu lorsque les filles choisissent leur carriere. Notre etude a pour objet la conception et l'evaluation de l'efficacite d'un materiel pedagogique concu specifiquement pour ameliorer les experiences d'apprentissage en sciences et en TIC des filles de 9e annee au Nouveau-Brunswick. L'approche pedagogique privilegiee dans notre materiel a mis en oeuvre des strategies pedagogiques issues des meilleures pratiques que nous avons identifiees et qui visaient particulierement l'augmentation du sentiment d'auto-efficacite et de l'interet des filles pour ces disciplines. Ce materiel disponible par Internet a l'adresse http://www.umoncton.ca/lirettn/scientic est directement en lien avec le programme d'etudes en sciences de la nature de 9e annee du Nouveau-Brunswick. L'evaluation de l'efficacite de notre materiel pedagogique a ete faite selon deux grandes etapes methodologiques: 1) l'evaluation de l'utilisabilite et de la convivialite du materiel et 2) l'evaluation de l'effet du materiel en fonction de diverses variables reliees a l'interet et au sentiment d'auto-efficacite des filles en sciences et en TIC. Cette recherche s'est inscrite dans un paradigme pragmatique de recherche. Le pragmatisme a guide nos choix en ce qui a trait au modele de recherche et des techniques utilisees. Cette recherche a associe a la fois des techniques qualitatives et quantitatives, particulierement en ce qui concerne la collecte et l'analyse de donnees. Les donnees recueillies dans la premiere etape de l'evaluation de l'utilisabilite et de la convivialite du materiel par les enseignantes et les enseignants de sciences et les filles ont revele que le materiel concu est tres utilisable et convivial. Toutefois quelques petites ameliorations seront apportees a une version subsequente afin de faciliter davantage la navigation. Quant a l'evaluation des effets du materiel concu sur les variables reliees au sentiment d'auto-efficacite et aux interets lors de l'etape quasi experimentale, nos donnees qualitatives ont indique que ce materiel a eu des effets positifs sur le sentiment d'auto-efficacite et sur les interets des filles qui l'ont utilise. Toutefois, nos donnees quantitatives n'ont pas permis d'inferer un lien causal direct entre l'utilisation du materiel et l'augmentation du sentiment d'auto-efficacite et des interets des filles en sciences et en TIC. A la lumiere des resultats obtenus, nous avons conclu que le materiel a eu les effets escomptes. Donc, nous recommandons la creation et l'utilisation de materiel de ce genre dans toutes les classes de sciences de la 6e annee a la 12e annee au Nouveau-Brunswick.

Hydrodynamic Coating of a Fiber

NASA Astrophysics Data System (ADS)

Quéré, D.; de Ryck, A.

We discuss how a solid (especially a fiber) is coated when drawn out of a bath of liquid. 1. For slow withdrawals out of pure viscous liquids, the data are found to be fitted by the famous Landau law: then, the coating results from a balance between viscosity and capillarity. For quicker withdrawals, the thickness of the entrained film suddenly diverges, at a velocity on order 1 m/s. Inertia is shown to be responsible for this effect. At still higher velocities, the thickness decreases with the velocity because the solid can only entrain the viscous boundary layer. 2. For complex fluids, surface effects are found in the low velocity regime: out of a surfactant solution, films are thicker than predicted by Landau, by a factor of order 2. The thickening factor is shown to be fixed by the Marangoni flow due to the presence of surfactants; out of an emulsion, the film can be enriched with oil , which can be understood by a simple model of capture; out of a polymer solution, a strong swelling of the film is observed if normal stresses are present. Hence, the problem has two families of solution: (i) at low velocity, the thickness of the layer is fixed by a balance between viscous and surface forces and thus is sensitive to the presence of surfactants, or other heterogeneities; (ii) at high velocity, inertia must be considered and the film thickness is fixed by the bulk properties of the liquid (density and viscosity). In these regimes, it is not affected by the presence of surfactants in the bath. Nous décrivons le dépôt de liquide sur un solide (le plus souvent une fibre) qui advient quand on tire ce solide d'un bain. 1. Si le retrait se fait lentement hors d'un liquide pur et visqueux, les données expérimentales suivent la loi de Landau : le dépôt résulte d'un compromis entre forces visqueuses et forces capillaires. Pour des retraits plus rapides, on observe que l'épaisseur du dépôt diverge, pour une vitesse de l'ordre du mètre par seconde. Nous montrons comment l'inertie du fluide engendre un tel effet. Plus vite encore, l'épaisseur décroît lentement avec la vitesse, le solide ne parvenant à entraîner avec lui que la couche limite visqueuse qu'il a mis en mouvement. 2. Pour des liquides complexes, des effets de surface sont observés dans le régime basse vitesse : hors d'une solution de tensioactifs, les films sont plus épais que ce que prévoit la loi de Landau, d'un facteur 2 environ. Nous montrons que l'épaississement est déterminé par l'écoulement Marangoni dû à la présence des tensioactifs ; hors d'une émulsion, le film peut être enrichi en huile, ce que l'on peut interpréter à l'aide d'un modèle de capture ; hors d'une solution de polymère, on observe un fort gonflement du film dès que la solution est semi-diluée, à cause de l'effet des contraintes normales (effet Weissenberg). Le problème étudié a donc deux familles de solution : (i) à basse vitesse, le dépôt résulte d'un compromis entre viscosité et capillarité, si bien qu'il est sensible à la présence dans le bain d'hétérogénéités (tensioactifs, gouttes d'huile) ; (ii) à plus grande vitesse, l'inertie doit être prise en compte et l'épaisseur du film est alors liée aux propriétés de volume du liquide (densité et viscosité).

The Wasp-Waist Nebula: VLA Ammonia Observations of the Molecular Core Envelope In a Unique Class 0 Protostellar System

NASA Technical Reports Server (NTRS)

Wiseman, Jennifer

2010-01-01

The Wasp-Waist Nebula was discovered in the IRAC c2d survey of the Ophiuchus starforming clouds. It is powered by a well-isolated, low-luminosity, low-mass Class 0 object. Its weak outflow has been mapped in the CO (3-2) transition with the JCMT, in 2.12 micron H2 emission with WIRC (the Wide-Field Infrared Camera) on the Hale 5-meter, and, most recently, in six H2 mid-infrared lines with the IRS (InfraRed Spectrograph) on-board the Spitzer Space Telescope; possible jet twisting structure may be evidence of unique core dynamics. Here, we report results of recent VLA ammonia mapping observations of the dense gas envelope feeding the central core protostellar system. We describe the morphology, kinematics, and angular momentum characteristics of this unique system. The results are compared with the envelope structure deduced from IRAC 8-micron absorption of the PAH (polycyclic aromatic hydrocarbon) background emission from the cloud.

The unique karyotype of Henochilus wheatlandii, a critically endangered fish living in a fast-developing region in Minas Gerais State, Brazil.

PubMed

Silva, Priscilla C; Santos, Udson; Travenzoli, Natália M; Zanuncio, Jose C; Cioffi, Marcelo de B; Dergam, Jorge A

2012-01-01

Henochilus wheatlandii, the only species of this genus, is critically endangered and was considered extinct for over a century. The rediscovery of this fish in 1996 made it possible to study its phylogenetic relationships with other species in the subfamily Bryconinae. The aim of this study was to characterise the karyotype of H. wheatlandii. Standard staining, C-positive heterochromatin and nucleolar organiser region (NOR) banding, chromomycin A(3) staining, and fluorescent in situ hybridisation (FISH) using 5S rDNA and 18S rDNA probes were conducted on nineteen specimens collected in the Santo Antonio River, a sub-basin of the Doce River in Ferros municipality, Minas Gerais State, Brazil. Henochilus wheatlandii shared the same diploid number and chromosome morphology as other species of Bryconinae. However, its heterochromatin distribution patterns, NOR localisation, and FISH patterns revealed a cytogenetic profile unique among Neotropical Bryconinae, emphasizing the evolutionary uniqueness of this threatened species.

The Unique Karyotype of Henochilus wheatlandii, a Critically Endangered Fish Living in a Fast-Developing Region in Minas Gerais State, Brazil

PubMed Central

Silva, Priscilla C.; Santos, Udson; Travenzoli, Natália M.; Zanuncio, Jose C.; Cioffi, Marcelo de B.; Dergam, Jorge A.

2012-01-01

Henochilus wheatlandii, the only species of this genus, is critically endangered and was considered extinct for over a century. The rediscovery of this fish in 1996 made it possible to study its phylogenetic relationships with other species in the subfamily Bryconinae. The aim of this study was to characterise the karyotype of H. wheatlandii. Standard staining, C-positive heterochromatin and nucleolar organiser region (NOR) banding, chromomycin A3 staining, and fluorescent in situ hybridisation (FISH) using 5S rDNA and 18S rDNA probes were conducted on nineteen specimens collected in the Santo Antonio River, a sub-basin of the Doce River in Ferros municipality, Minas Gerais State, Brazil. Henochilus wheatlandii shared the same diploid number and chromosome morphology as other species of Bryconinae. However, its heterochromatin distribution patterns, NOR localisation, and FISH patterns revealed a cytogenetic profile unique among Neotropical Bryconinae, emphasizing the evolutionary uniqueness of this threatened species. PMID:22848754

Nanostructured magnetic particles with polystyrene and their magnetorheological applications.

PubMed

Fang, Fei Fei; Choi, Hyoung Jin

2011-03-01

Magnetorheological (MR) fluids are known to be colloidal suspensions of magnetic particles in a non-magnetic fluid, and exposure to a magnetic field transforms the fluid into a plastic-like solid in milliseconds. To improve the stability against sedimentation and uniform dispersion, two different MR candidates, soft magnetic carbonyl iron (CI) microspheres and magnetite (Fe3O4) particles were modified with polystyrene to be applied for MR fluids in this study. After modification, their unique morphology, crystalline structure and magnetic properties were examined in addition to MR performance and sedimentation characteristics. It was found that this embedded morphology not only effectively prevents direct contact of the magnetic species thus improving particle dispersion but also leads to obvious change in their density, compared with the traditional polymer coating method with a core-shell structure.

What Happens during Natural Protein Fibre Dissolution in Ionic Liquids

PubMed Central

Chen, Jingyu; Vongsanga, Kylie; Wang, Xungai; Byrne, Nolene

2014-01-01

Here, we monitor the dissolution of several natural protein fibres such as wool, human hair and silk, in various ionic liquids (ILs). The dissolution of protein-based materials using ILs is an emerging area exploring the production of new materials from waste products. Wool is a keratin fibre, which is extensively used in the textiles industry and as a result has considerable amounts of waste produced each year. Wool, along with human hair, has a unique morphology whereby the outer layer, the cuticle, is heavily cross linked with disulphide bonds, whereas silk does not have this outer layer. Here we show how ILs dissolve natural protein fibres and how the mechanism of dissolution is directly related to the structure and morphology of the wool fibre. PMID:28788183

A remarkable new genus and a new species of chewing louse (Phthiraptera, Ischnocera, Philopteridae) from Brazil

PubMed Central

Valim, Michel P.; Cicchino, Armando C.

2015-01-01

Abstract A new genus of chewing louse as Bobdalgleishia, and its type species Bobdalgleishia stephanophallus sp. n. (Phthiraptera) belonging to the Brueelia-complex (Ischnocera: Philopteridae) are described. Adults of the new species are fully described, illustrated and compared morphologically with the type species of Motmotnirmus Mey & Barker, 2014, which is its closest relative. The type host of Bobdalgleishia stephanophallus is a subspecies of the great jacamar Jacamerops aureus ridgwayi Todd, 1943, an endemic Amazonian bird distributed in northern Brazil, and the type locality is the State of Pará. Bobdalgleishia is a remarkable genus with unique morphological and chaetotaxic characters which readily separate it from other members of the Brueelia-complex, in particular by having the first two marginal temporal and ocular setae very long. PMID:26798280

Review of National Work Programme on the Long Term Effects of Sustained High G on the Cervical Spine (Analyse du programme de travail national : les effets long terme sur la colonne cervicale d’un nombre de G lev et prolong )

DTIC Science & Technology

2008-12-01

Prof. Karin Harms-Ringdahl, PhD, RPT Karolinska Institutet Department of Neurobiology, Care Sciences, and Society Division of Physiotherapy 23100...Äng Karolinska Institutet Department of Neurobiology, Care Sciences, and Society Division of Physiotherapy Alfred Nobels Allé 23100 SE-14183...report is in preparation. The RAF has an ongoing project (from August 2006 to September 2007) determining the need for physiotherapy for aircrew on the

Specialists Meeting on Wing-with-Stores Flutter

DTIC Science & Technology

1975-04-01

I, 150 -z20L0 250 00 350o PYLON COMPONENT MODE (PITCH4-) GENER~ALISED INERTIA A C, 2-20 FIG. 13. AIRCRAFT BENDING MODE FREQUENCI ES , FOR SfORES ON...ldgbre ddportance tandis Gus J ’effet inverse eut o’uorv6 pour ] es sections au- .elth du rdscteur. Calcul et exp~rionce oont v,-. lw. accord at...nontrent que i’interaction du r’~acteur sur i.aile eat trbs locale ot d’intensitC6 s;.ffismaaent faible pour pouvoir 6trc n~glii4e dana lea calculs do

Energy Security in Yemen

DTIC Science & Technology

2009-09-01

le présent rapport, nous analysons la sécurité du secteur énergétique et de son infrastructure au Yémen et nous examinons les répercussions...conflits. Toutefois, le problème fondamental du secteur de l‘énergie au Yémen est l‘épuisement des réserves pétrolières, menant à une réduction rapide des...niveaux de production de pétrole. Le déclin du secteur de l‘énergie dans ce pays aura un effet très négligeable sur les réserves énergétiques

Conference Proceedings on Effects of Adverse Weather on Aerodynamics Held in Toulouse, France on 29 April-1 May 1991 (Les Effets des Conditions Meteorologiques Adverses sur l’Aerodynamique)

DTIC Science & Technology

1991-12-01

and a refrigeration system and of a large, free jet wind tunnel. A schematic of the facil- heat exchanger that cools the air to temperatures as low ity...rotor testing turers, but correlations for heat and mass transfer over would involve the use of simulated ice applied to the wet airfoil surfaces are not...and also has incidence. A transient heat conduction the ability to introduce a correction for analysis applied around the rotor azimuth viscous effects

The Effect of Prolonged Military Activities in Man. Physiological and Biochemical Changes. Possible Means of Rapid Recuperation (les Effets d’activites mi1itaires prolongees sur l’homme. Changements physiologiques et biochimiques. Moyens possibles de recuperation rapide.)

DTIC Science & Technology

2001-03-01

possibilities to treat many groups in a repeated analysis the parametric methods were preferred. Student’s t-test has been used to identify significant...activation of the adrenal cortical glands and could therefore use the central POMC- serotonin pathway. This effect is observed in moderately trained...their unusual hours of arrival and departure deserves more study. It would be useful to know what selections they have and what they are making

Validation of an Acoustic Head Simulator for the Evaluation of Personal Hearing Protection Devices

DTIC Science & Technology

2004-11-01

et recouvert de peau artificielle. Les cavités de chaque côté permettent l’insertion de modules d’oreilles qui reproduisent les mécanismes des ...aux spécifications publiées. Ces différences n’ont pas influé sur la perte d’insertion. Après correction pour tenir compte des effets de la...un simulateur de tête époxy chargé d’aluminium et recouvert de peau artificielle. La tête est soutenue par un module de cou souple rattaché à un

Intellectual Property Rights: Lecture Series Held in London, (United Kingdom) on 21-22 October 1991, in Brussels (Belgium) on 24-25 October 1991 and in Arlington, Virginia on 6-7 November 1991

DTIC Science & Technology

1991-01-01

des rdalitfs diverses ct niouvantes sous I’cffet croisd des 6volutions techniques et &conomIques. I en rdsulte tine...r6le est croissant. Si un tel mouvement s’observe dans nombre de pays, cla ne signifie pas qu’il leur soit commun. En effet, la confrontation des ...conceptions nationales, voire rgionales, est dIdj engagdc en raison de l’internationalisation des activitds de transfert de technologies et de

Atmospheric Propagation Effects through Natural and Man-Made Obscurants for Visible to MM-Wave Radiation (Les Effets des Conditions Defavorables de Propagation sur les Systemes Optiques, IR et a Ondes Millimetiques)

DTIC Science & Technology

1993-11-01

In this section, we recall definitions of dual linear incoherent KH,’ radar measurables, rainfall rate and the specific attenuation (7) due to...reflectivity data. Two different path lengths (d1,) 10 and 20 from a C-band dual linear polarization radar measurements, Km., have been considered...model for simulation of dual linear polarization radar 7. REFERENCES measurement fields", to be published on lEE 1. Leitao, M. J. and P. A. Watson

Perimysial fibroblasts of extraocular muscle, as unique as the muscle fibers.

PubMed

Kusner, Linda L; Young, Andrew; Tjoe, Steven; Leahy, Patrick; Kaminski, Henry J

2010-01-01

Extraocular muscle (EOM) has a distinct skeletal muscle phenotype. The hypothesis for the study was that fibroblasts support the unique EOM phenotype and that perimysial fibroblasts derived from EOM have properties that distinguish them from fibroblasts derived from other skeletal muscle. Perimysial fibroblasts from leg muscle (LM-Fibro) and EOM (EOM-Fibro) of mice were derived and maintained in culture. EOM- and LM-Fibro were assessed morphologically and for vimentin, smooth muscle actin, and Thy-1 immunoreactivity. DNA microarray analysis was performed on LM- and EOM-Fibro grown in conditions that support myoblast differentiation. To assess trophic interactions, co-cultures of myoblasts from established cell lines, CL-EOM and CL-LM with, EOM- or LM-Fibro were performed in direct contact and in a permeable filter support culture. The degree of myotube maturation was assessed by the percentage of myotubes with more than three myonuclei per myotube. EOM- and LM-Fibro cells exhibited distinct morphologies. Both cell types proliferated as a monolayer and expressed vimentin. Fifty-five percent (SD 4.4%) of EOM-Fibro were Thy-1 positive compared with only 24% (SD 4.4%) of LM-Fibro. DNA microarray analysis demonstrated differential expression of structural, immune response, and metabolism-related genes between EOM- and LM-Fibro. Co-cultures demonstrated that mature myotube formation in EOM-derived cell lines was supported to a greater extent by EOM-Fibro than by LM-Fibro, compared with CL-EOM grown with LM-Fibro. Fibroblasts from EOM demonstrate distinct properties that distinguish them from leg muscle-derived fibroblasts. The distinct properties of EOM-Fibro may support the unique EOM phenotype and contribute to their differential involvement in disease.

Isotope effect in the organic superconductor β_H-(BEDT-TTF)2I3 where BEDT-TTF is bis (ethylenedithiotetrathiafulvalene)

NASA Astrophysics Data System (ADS)

Auban-Senzier, P.; Bourbonnais, C.; Jérome, D.; Lenoir, C.; Batail, P.; Canadell, E.; Buisson, J. P.; Lefrant, S.

1993-03-01

We have performed the simultaneous investigation of the isotope effect on the superconducting transition and on the Raman spectra in the organic superconductor β_H-(BEDT-TTF)2I3 (T_c = 8 K). For this purpose, we substitute ^{13}C for ^{12}C on the carbon sites of the central double bond of BEDT-TTF molecule. The isotope shifts measured by Raman experiments can be fairly well explained by standard molecular dynamics. However, the critical temperature is lowered by 0.2 K in the ^{13}C enriched material. We analyse the possible sources of this remarkable downward shift which leads to an isotope coefficient higher than the BCS value. The extended-Hückel calculations of the density of states for the two HOMO bands of β_H-(BEDT-TTF)2I3 do show that, within the framework of a weak coupling theory, its sizeable variation on the scale of ω_D cannot account for the observed isotope effect. On the other hand, we discuss how inelastic electronic scattering observed in resistivity measurements just above T_c can lead through a pair breaking mechanism to a sizeable increase of the isotope coefficient. Nous présentons une étude simultanée d'effet isotopique sur la transition supraconductrice et les spectres Raman dans le supraconducteur organique β_H-(BEDT-TTF)2I3 (T_c = 8 K). Pour cela, nous avons synthétisé le composé dans lequel les atomes de carbone de la double liaison centrale de la molécule BEDT-TTF sont substitués par l'isotope ^{13}C. Les déplacements isotopiques mesurés par spectroscopie Raman sont bien expliqués par la dynamique moléculaire standard. Cependant, la température critique est abaissée de 0.2 K dans le matériau enrichi en ^{13}C. Nous étudions les origines possibles de cet effet qui permet d'obtenir un coefficient isotopique supérieur à la valeur BCS. Des calculs de la densité d'états effectués par la méthode de Hückel étendue pour les deux bandes HOMO du composé montrent que, dans le cadre d'une théorie de couplage faible, son importante variation à l'échelle de ω_D ne peut expliquer l'effet observé. D'autre part, nous expliquons comment la diffusion électronique inélastique observée en résistivité juste au-dessus de T_c peut conduire via un mécanisme de brisure de paires, à une augmentation significative du coefficient isotopique.

Les recommandations thérapeutiques relatives aux effets secondaires extrapyramidaux associés à l’utilisation d’antipsychotiques de deuxième génération chez les enfants et les adolescents

PubMed Central

Pringsheim, Tamara; Doja, Asif; Belanger, Stacey; Patten, Scott

2012-01-01

HISTORIQUE ET OBJECTIF : L’utilisation d’antipsychotiques augmente chez les enfants. Le présent article visait à orienter les cliniciens quant à la prise en charge clinique des effets secondaires extrapyramidaux des antipsychotiques de deuxième génération. MÉTHODOLOGIE : Les publications, les entrevues avec des informateurs clés et des échanges avec les membres d’un groupe de discussion et les partenaires ont permis de déterminer les principaux secteurs cliniques d’orientation et les préférences quant à la structure des présentes recommandations. Les membres responsables des lignes directrices ont reçu le projet de recommandations, ont évalué l’information recueillie grâce à une analyse bibliographique systématique et ont utilisé un processus de groupe nominal pour parvenir à un consensus quant aux recommandations thérapeutiques. Les lignes directrices contiennent une description des anomalies neurologiques souvent observées avec l’utilisation d’antipsychotiques ainsi que les recommandations sur le moyen d’examiner et de quantifier ces anomalies. Une démarche séquentielle sur la prise en charge des anomalies neurologiques est présentée. RÉSULTATS : On peut observer plusieurs types de symptômes extrapyramidaux attribuables à l’utilisation d’antipsychotiques chez les enfants, y compris la dystonie aiguë, l’akathisie, le parkinsonisme et la dyskinésie tardive, toutes induites par les neuroleptiques, de même que la dystonie tardive, l’akathisie tardive et les dyskinésies de sevrage. La forte majorité des données probantes sur le traitement des troubles du mouvement induits par les antipsychotiques proviennent de patients adultes atteints de schizophrénie. Étant donné le peu de données pédiatriques, les recommandations découlent de publications portant tant sur des adultes que sur des enfants. Compte tenu des limites de généralisation des données provenant de sujets adultes pour des enfants, il faudrait évaluer ces recommandations d’après les avis d’experts plutôt que d’après les données probantes. CONCLUSION : Les cliniciens doivent savoir que les antipsychotiques de deuxième génération ont le potentiel d’induire des effets secondaires neurologiques et devraient faire preuve d’une extrême vigilance lorsqu’ils en prescrivent. PMID:24082814

Apport maternel chez la balane tropicale : Plasticite de l'allocation de la ressource trophique pour la production larvaire en conditions de limitation nutritionnelle et de stress environnemental

NASA Astrophysics Data System (ADS)

Freuchet, Florian

Dans le milieu marin, l'abondance du recrutement depend des processus qui vont affecter les adultes et le stock de larves. Sous l'influence de signaux fiables de la qualite de l'habitat, la mere peut augmenter (effet maternel anticipatoire, 'anticipatory mother effects', AME) ou reduire (effet maternel egoiste, 'selfish maternai effects', SME) la condition physiologique de la progeniture. Dans les zones tropicales, generalement plus oligotrophes, la ressource nutritive et la temperature sont deux composantes importantes pouvant limiter le recrutement. Les effets de l'apport nutritionnel et du stress thermique sur la production de larves et sur la stategie maternelle adoptee ont ete testes dans cette etude. Nous avons cible la balane Chthamalus bisinuatus (Pilsbry) comme modele biologique car el1e domine les zones intertidales superieures le long des cotes rocheuses du Sud-Est du Bresil (region tropicale). Les hypotheses de depart stipulaient que l'apport nutritionnel permet aux adultes de produire des larves de qualite elevee et que le stress thermique genere une ponte precoce, produisant des larves de faible qualite. Afin de tester ces hypotheses, des populations de C. bisinuatus ont ete elevees selon quatre groupes experimentaux differents, en combinant des niveaux d'apport nutritionnel (eleve et faible) et de stress thermique (stresse et non stresse). Des mesures de survie et de conditions physiologiques des adultes et des larves ont permis d'identifier les reponses parentales pouvant etre avantageuses dans un environnement tropical hostile. L'analyse des profils en acides gras a ete la methode utilisee pour evaluer la qualite physiologique des adultes et de larves. Les resultats du traitement alimentaire (fort ou faible apport nutritif), ne montrent aucune difference dans l'accumulation de lipides neutres, la taille des nauplii, l'effort de reproduction ou le temps de survie des nauplii en condition de jeune. Il semble que la faible ressource nutritive est compensee par les meres qui adoptent un modele AME qui se traduit par l'anticipation du milieu par les meres afin de produire des larves au phenotype approprie. A l'ajout d'un stress thermique, on observe des diminutions de 47% de la production de larves et celles-ci etaient 18 microm plus petites. Les meres semblent utiliser un modele SME caracterise par une diminution de la performance des larves. Suite a ces resultats, nous emettons l'hypothese qu'en zone subtropicale, comme sur les cotes de l'etat de Sao Paulo, l'elevation de la temperature subie par les balanes n'est, a priori, pas dommageable pour leur organisme si eIle est combinee a un apport nutritif suffisant.

Developpement d'outils quantitatifs pour le suivi par imagerie TEP/TDM de la reponse a la chimiotherapie et de sa toxicite

NASA Astrophysics Data System (ADS)

Croteau, Etienne

L'objectif de ce projet de doctorat est de developper des outils quantitatifs pour le suivi des traitements de chimiotherapie pour le cancer du sein et de leurs effets cardiotoxiques a l'aide de l'imagerie TEP dynamique. L'analyse cinetique en TEP dynamique permet l'evaluation de parametres biologiques in vivo. Cette analyse peut etre utilise pour caracteriser la reponse tumorale a la chimiotherapie et les effets secondaires nefastes qui peuvent en resulter. Le premier article de cette these decrit la mise au point des techniques d'analyse cinetique qui utilisent la fonction d'entree d'un radiotraceur derive de l'image dynamique. Des corrections de contamination radioactive externe (epanchement) et de l'effet de volume partiel ont ete necessaires pour standardiser l'analyse cinetique et la rendre quantitative. Le deuxieme article porte sur l'evaluation d'un nouveau radiotraceur myocardique. Le 11C-acetoacetate, un nouveau radiotraceur base sur un corps cetonique, a ete compare au 11C-acetate, couramment utilise en imagerie cardiaque TEP. L'utilisation de 3H-acetate et 14C-acetoacetate ont permis d'elucider la cinetique de ces traceurs depuis la fonction d'entree et la captation par les mitochondries cardiaques qui reflete la consommation en oxygene, jusqu'a la liberation de leurs principaux metabolites reciproques (3H20 et 14CO2). Le troisieme et dernier article de cette these presente l'integration d'un modele qui evalue la reserve cardiaque de perfusion et de consommation en oxygene. Un modele de cardiomyopathie a ete etabli a l'aide d'un agent chimiotherapeutique contre le cancer du sein, la doxorubicine, reconnu comme etant cardiotoxique. Un protocole de repos/effort a permis d'evaluer la capacite d'augmentation de perfusion et de consommation en oxygene par le coeur. La demonstration d'une reserve cardiaque reduite caracterise la cardiotoxicite. La derniere contribution de cette these porte sur la mise au point de methodes peu invasives pour mesurer la fonction d'entree en modele animal avec l'utilisation de l'artere caudale et un compteur microvolumetrique, la bi-modalite TEP/IRM dynamique avec le Gd-DTPA et l'etablissement d'un modele d'evaluation simultane de cardiotoxicite et reponse tumorale chez la souris. Le developpement d'outils d'analyse TEP dans l'evaluation de la cardiotoxicite lors de traitements du canter du sein permet de mieux comprendre la relation entre les dommages mitochondriaux et la diminution de la fraction d'ejection. Mots cles : Tomographie d'emission par positrons (TEP), analyses cinetiques, IIC-acetate, 11Cacetoacetate, cardiotoxicite.

The unique radar scattering properties of silicic lava flows and domes

NASA Technical Reports Server (NTRS)

Plaut, Jeffrey J.; Stofan, Ellen R.; Anderson, Steven W.; Crown, David A.

1995-01-01

Silicic (silica-rich) lava flows, such as rhyolite, rhyodacite, and dacite, possess unique physical properties primarily because of the relatively high viscosity of the molten lava. Silicic flows tend to be thicker than basaltic flows, and the resulting large-scale morphology is typically a steep-sided dome or flow lobe, with aspect ratios (height/length) sometimes approaching unity. The upper surfaces of silicic domes and flows are normally emplaced as relatively cool, brittle slabs that fracture as they are extruded from the central vent areas, and are then rafted away toward the flow margin as a brittle carapace above a more ductile interior layer. This mode of emplacement results in a surface with unique roughness characteristics, which can be well-characterized by multiparameter synthetic aperture radar (SAR) observations. In this paper, we examine the scattering properties of several silicic domes in the Inyo volcanic chain in the Eastern Sierra of California, using AIRSAR and TOPSAR data. Field measurements of intermediate-scale (cm to tens of m) surface topography and block size are used to assess the mechanisms of the scattering process, and to quantify the unique roughness characteristics of the flow surfaces.

Reticulate Structures Reveal the Significance of Cell Motility in the Morphogenesis of Complex Microbial Structures in Pavilion Lake, British Columbia

NASA Astrophysics Data System (ADS)

Shepard, R.

2008-12-01

Microbial communities are architects of incredibly complex and diverse morphological structures. Each morphology is a snapshot that reflects the complex interactions within the microbial community and between the community and its environment. Characterizing morphology as an emergent property of microbial communities is thus relevant to understanding the evolution of multicellularity and complexity in developmental systems, to the identification of biosignatures, and to furthering our understanding of modern and ancient microbial ecology. Recently discovered cyanobacterial mats in Pavilion Lake, British Columbia construct unusual complex architecture on the scale of decimeters that incorporates significant void space. Fundamental mesoscale morphological elements include terraces, arches, bridges, depressions, domes, and pillars. The mats themselves also exhibit several microscale morphologies, with reticulate structures being the dominant example. The reticulate structures exhibit a diverse spectrum of morphologies with endmembers characterized by either angular or curvilinear ridges. In laboratory studies, aggregation into reticulate structures occurs as a result of the random gliding and colliding among motile cyanobacterial filaments. Likewise, when Pavilion reticulate mats were sampled and brought to the surface, cyanobacteria invariably migrated out of the mat onto surrounding surfaces. Filaments were observed to move rapidly in clumps, preferentially following paths of previous filaments. The migrating filaments organized into new angular and ropey reticulate biofilms within hours of sampling, demonstrating that cell motility is responsible for the reticulate patterns. Because the morphogenesis of reticulate structures can be linked to motility behaviors of filamentous cyanobacteria, the Willow Point mats provide a unique natural laboratory in which to elucidate the connections between a specific microbial behavior and the construction of complex microbial community morphology. To this end, we identified and characterized fundamental building blocks of the mesoscale morphologies, including bridges, anchors, and curved edges. These morphological building blocks were compared with the suite of motility behaviors and patterns observed in reticulate morphogenesis. Results of this comparison suggest that cyanobacterial motility plays a significant and often dominant role in the morphogenesis of the entire suite of morphologies observed in the microbial mats of Pavilion Lake.

Bentho-pelagic divergence of cichlid feeding architecture was prodigious and consistent during multiple adaptive radiations within African rift-lakes.

PubMed

Cooper, W James; Parsons, Kevin; McIntyre, Alyssa; Kern, Brittany; McGee-Moore, Alana; Albertson, R Craig

2010-03-08

How particular changes in functional morphology can repeatedly promote ecological diversification is an active area of evolutionary investigation. The African rift-lake cichlids offer a calibrated time series of the most dramatic adaptive radiations of vertebrate trophic morphology yet described, and the replicate nature of these events provides a unique opportunity to test whether common changes in functional morphology have repeatedly facilitated their ecological success. Specimens from 87 genera of cichlid fishes endemic to Lakes Tanganyka, Malawi and Victoria were dissected in order to examine the functional morphology of cichlid feeding. We quantified shape using geometric morphometrics and compared patterns of morphological diversity using a series of analytical tests. The primary axes of divergence were conserved among all three radiations, and the most prevalent changes involved the size of the preorbital region of the skull. Even the fishes from the youngest of these lakes (Victoria), which exhibit the lowest amount of skull shape disparity, have undergone extensive preorbital evolution relative to other craniofacial traits. Such changes have large effects on feeding biomechanics, and can promote expansion into a wide array of niches along a bentho-pelagic ecomorphological axis. Here we show that specific changes in trophic anatomy have evolved repeatedly in the African rift lakes, and our results suggest that simple morphological alterations that have large ecological consequences are likely to constitute critical components of adaptive radiations in functional morphology. Such shifts may precede more complex shape changes as lineages diversify into unoccupied niches. The data presented here, combined with observations of other fish lineages, suggest that the preorbital region represents an evolutionary module that can respond quickly to natural selection when fishes colonize new lakes. Characterizing the changes in cichlid trophic morphology that have contributed to their extraordinary adaptive radiations has broad evolutionary implications, and such studies are necessary for directing future investigations into the proximate mechanisms that have shaped these spectacular phenomena.

Functional skeletal morphology and its implications for locomotory behavior among three genera of myosoricine shrews (Mammalia: Eulipotyphla: Soricidae)

USGS Publications Warehouse

Woodman, Neal; Stabile, Frank A.

2015-01-01

Myosoricinae is a small clade of shrews (Mammalia, Eulipotyphla, Soricidae) that is currently restricted to the African continent. Individual species have limited distributions that are often associated with higher elevations. Although the majority of species in the subfamily are considered ambulatory in their locomotory behavior, species of the myosoricine genus Surdisorex are known to be semifossorial. To better characterize variation in locomotory behaviors among myosoricines, we calculated 32 morphological indices from skeletal measurements from nine species representing all three genera that comprise the subfamily (i.e., Congosorex, Myosorex, Surdisorex) and compared them to indices calculated for two species with well-documented locomotory behaviors: the ambulatory talpid Uropsilus soricipes and the semifossorial talpid Neurotrichus gibbsii. We summarized the 22 most complete morphological variables by 1) calculating a mean percentile rank for each species and 2) using the first principal component from principal component analysis of the indices. The two methods yielded similar results and indicate grades of adaptations reflecting a range of potential locomotory behaviors from ambulatory to semifossorial that exceeds the range represented by the two talpids. Morphological variation reflecting grades of increased semifossoriality among myosoricine shrews is similar in many respects to that seen for soricines, but some features are unique to the Myosoricinae.

Adaptation and Convergent Evolution within the Jamesonia-Eriosorus Complex in High-Elevation Biodiverse Andean Hotspots

PubMed Central

Sánchez-Baracaldo, Patricia; Thomas, Gavin H.

2014-01-01

The recent uplift of the tropical Andes (since the late Pliocene or early Pleistocene) provided extensive ecological opportunity for evolutionary radiations. We test for phylogenetic and morphological evidence of adaptive radiation and convergent evolution to novel habitats (exposed, high-altitude páramo habitats) in the Andean fern genera Jamesonia and Eriosorus. We construct time-calibrated phylogenies for the Jamesonia-Eriosorus clade. We then use recent phylogenetic comparative methods to test for evolutionary transitions among habitats, associations between habitat and leaf morphology, and ecologically driven variation in the rate of morphological evolution. Páramo species (Jamesonia) display morphological adaptations consistent with convergent evolution in response to the demands of a highly exposed environment but these adaptations are associated with microhabitat use rather than the páramo per se. Species that are associated with exposed microhabitats (including Jamesonia and Eriorsorus) are characterized by many but short pinnae per frond whereas species occupying sheltered microhabitats (primarily Eriosorus) have few but long pinnae per frond. Pinnae length declines more rapidly with altitude in sheltered species. Rates of speciation are significantly higher among páramo than non-páramo lineages supporting the hypothesis of adaptation and divergence in the unique Páramo biodiversity hotspot. PMID:25340770

Forced swimming sabotages the morphological and synaptic maturation of newborn granule neurons and triggers a unique pro-inflammatory milieu in the hippocampus.

PubMed

Llorens-Martín, María; Jurado-Arjona, Jerónimo; Bolós, Marta; Pallas-Bazarra, Noemí; Ávila, Jesús

2016-03-01

Recent experimental data suggest that mood disorders are related to inflammatory phenomena and have led to the "inflammatory hypothesis of depression". Given that the hippocampus is one of the most affected areas in these disorders, we used a model of acute stress (the Porsolt test) to evaluate the consequences of forced swimming on two crucial events related to the pathophysiology of major depression: the functional maturation of newborn granule neurons; and the hippocampal inflammatory milieu. Using PSD95:GFP-expressing retroviruses, we found that forced swimming selectively alters the dendritic morphology of newborn neurons and impairs their connectivity by reducing the number and volume of their postsynaptic densities. In addition, acute stress triggered a series of morphological changes in microglial cells, together with an increase in microglial CD68 expression, thus suggesting the functional and morphological activation of this cell population. Furthermore, we observed an intriguing change in the hippocampal inflammatory milieu in response to forced swimming. Importantly, the levels of several molecules affected by acute stress (such as Interleukin-6 and eotaxin) have been described to also be altered in patients with depression and other mood disorders. Copyright © 2015 Elsevier Inc. All rights reserved.

An approach to localize the retinal blood vessels using bit planes and centerline detection.

PubMed

Fraz, M M; Barman, S A; Remagnino, P; Hoppe, A; Basit, A; Uyyanonvara, B; Rudnicka, A R; Owen, C G

2012-11-01

The change in morphology, diameter, branching pattern or tortuosity of retinal blood vessels is an important indicator of various clinical disorders of the eye and the body. This paper reports an automated method for segmentation of blood vessels in retinal images. A unique combination of techniques for vessel centerlines detection and morphological bit plane slicing is presented to extract the blood vessel tree from the retinal images. The centerlines are extracted by using the first order derivative of a Gaussian filter in four orientations and then evaluation of derivative signs and average derivative values is performed. Mathematical morphology has emerged as a proficient technique for quantifying the blood vessels in the retina. The shape and orientation map of blood vessels is obtained by applying a multidirectional morphological top-hat operator with a linear structuring element followed by bit plane slicing of the vessel enhanced grayscale image. The centerlines are combined with these maps to obtain the segmented vessel tree. The methodology is tested on three publicly available databases DRIVE, STARE and MESSIDOR. The results demonstrate that the performance of the proposed algorithm is comparable with state of the art techniques in terms of accuracy, sensitivity and specificity. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Development from childhood to adulthood increases morphological and functional inter-individual variability in the right superior temporal cortex.

PubMed

Bonte, Milene; Frost, Martin A; Rutten, Sanne; Ley, Anke; Formisano, Elia; Goebel, Rainer

2013-12-01

We study the developmental trajectory of morphology and function of the superior temporal cortex (STC) in children (8-9 years), adolescents (14-15 years) and young adults. We analyze cortical surface landmarks and functional MRI (fMRI) responses to voices, other natural categories and tones and examine how hemispheric asymmetry and inter-subject variability change across age. Our results show stable morphological asymmetries across age groups, including a larger left planum temporale and a deeper right superior temporal sulcus. fMRI analyses show that a rightward lateralization for voice-selective responses is present in all groups but decreases with age. Furthermore, STC responses to voices change from being less selective and more spatially diffuse in children to highly selective and focal in adults. Interestingly, the analysis of morphological landmarks reveals that inter-subject variability increases during development in the right--but not in the left--STC. Similarly, inter-subject variability of cortically-realigned functional responses to voices, other categories and tones increases with age in the right STC. Our findings reveal asymmetric developmental changes in brain regions crucial for auditory and voice perception. The age-related increase of inter-subject variability in right STC suggests that anatomy and function of this region are shaped by unique individual developmental experiences. © 2013.

Promoting Morphology with a Favorable Density of States Using Diiodooctane to Improve Organic Photovoltaic Device Efficiency and Charge Carrier Lifetimes

DOE PAGES

Garner, Logan E.; Bera, Abhijit; Larson, Bryon W.; ...

2017-06-06

Due to the inherent challenges in probing nanoscale properties within bulk heterojunction (BHJ) active layers of organic photovoltaic (OPV) devices, the relationship between morphology and nanoscale electronic structure is not well understood. Here, we employ scanning tunneling microscopy (STM) dI/dV imaging and localized density of states (DOS) spectra to investigate the influence of additives on morphology in a high-performance OPV system. In short, we are able to correlate the use of diiodooctane (DIO) additive with significant changes to the distribution of the localized DOS, most notably a broader distribution of PCE10 polymer HOMO levels and PC70BM fullerene LUMO levels, asmore » well as significantly smaller domain sizes and significantly higher overall device efficiencies. We further correlate this data with a nearly 3-fold increase in charge carrier lifetimes in the active layer when DIO is employed, determined by time-resolved microwave conductivity (TRMC) measurements. In conclusion, the results are consistent with the growing body of literature evidence that DIO promotes the formation of a polymer/fullerene mixed phase and therefore highlight the unique information that this combination of techniques can provide when investigating OPV active layer morphology.« less

The Role of Surface Chemistry in Adhesion and Wetting of Gecko Toe Pads

PubMed Central

Badge, Ila; Stark, Alyssa Y.; Paoloni, Eva L.; Niewiarowski, Peter H.; Dhinojwala, Ali

2014-01-01

An array of micron-sized setal hairs offers geckos a unique ability to walk on vertical surfaces using van der Waals interactions. Although many studies have focused on the role of surface morphology of the hairs, very little is known about the role of surface chemistry on wetting and adhesion. We expect that both surface chemistry and morphology are important, not only to achieve optimum dry adhesion but also for increased efficiency in self-cleaning of water and adhesion under wet conditions. Here, we used a plasma-based vapor deposition process to coat the hairy patterns on gecko toe pad sheds with polar and non-polar coatings without significantly perturbing the setal morphology. By a comparison of wetting across treatments, we show that the intrinsic surface of gecko setae has a water contact angle between 70–90°. As expected, under wet conditions, adhesion on a hydrophilic surface (glass) was lower than that on a hydrophobic surface (alkyl-silane monolayer on glass). Surprisingly under wet and dry conditions the adhesion was comparable on the hydrophobic surface, independent of the surface chemistry of the setal hairs. This work highlights the need to utilize morphology and surface chemistry in developing successful synthetic adhesives with desirable adhesion and self-cleaning properties. PMID:25323067

Alterations in blood-brain barrier function following acute hypertension: comparison of the blood-to-brain transfer of horseradish peroxidase with that of alpha-aminisobutyric acid

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

Ellison, M.D.B.

The blood-brain barrier (BBB) selectively restricts the blood-to-brain passage of many solutes owing to unique properties of cerebrovascular endothelial cell membranes. To date, experimental study of the BBB has been accomplished primarily through the use of two different methodological approaches. Morphological studies have mostly employed large molecular weight (MW) tracers to detect morphological alterations underlying increased permeability. Physiological studies, employing smaller, more physiologic tracers have successfully described, quantitatively, certain functional aspects of blood-to-brain transfer. The current work attempts to merge these two approaches and to consider barrier function/dysfunction from both a morphological and a functional perspective. Specifically, the study comparesmore » in rats, following acute hypertension, the cerebrovascular passage of /sup 14/C-alpha-aminoisobutyric acid (AIB) and that of horseradish peroxidase (HRP). The blood-to-brain passage of AIB and HRP were compared following acute hypertension, with regard to both the distributions of the tracer extravasation patterns and the magnitude of tracer extravasation. The results of this study suggest that traditional morphological barrier studies alone do not reveal all aspects of altered barrier status and that multiple mechanisms underlying increased BBB permeability may operate simultaneously during BBB dysfunction.« less

Large Magellanic Cloud Planetary Nebula Morphology: Probing Stellar Populations and Evolution.

PubMed

Stanghellini; Shaw; Balick; Blades

2000-05-10

Planetary nebulae (PNe) in the Large Magellanic Cloud (LMC) offer the unique opportunity to study both the population and evolution of low- and intermediate-mass stars, by means of the morphological type of the nebula. Using observations from our LMC PN morphological survey, and including images available in the Hubble Space Telescope Data Archive and published chemical abundances, we find that asymmetry in PNe is strongly correlated with a younger stellar population, as indicated by the abundance of elements that are unaltered by stellar evolution (Ne, Ar, and S). While similar results have been obtained for Galactic PNe, this is the first demonstration of the relationship for extragalactic PNe. We also examine the relation between morphology and abundance of the products of stellar evolution. We found that asymmetric PNe have higher nitrogen and lower carbon abundances than symmetric PNe. Our two main results are broadly consistent with the predictions of stellar evolution if the progenitors of asymmetric PNe have on average larger masses than the progenitors of symmetric PNe. The results bear on the question of formation mechanisms for asymmetric PNe-specifically, that the genesis of PNe structure should relate strongly to the population type, and by inference the mass, of the progenitor star and less strongly on whether the central star is a member of a close binary system.

Adaptation and convergent evolution within the Jamesonia-Eriosorus complex in high-elevation biodiverse Andean hotspots.

PubMed

Sánchez-Baracaldo, Patricia; Thomas, Gavin H

2014-01-01

The recent uplift of the tropical Andes (since the late Pliocene or early Pleistocene) provided extensive ecological opportunity for evolutionary radiations. We test for phylogenetic and morphological evidence of adaptive radiation and convergent evolution to novel habitats (exposed, high-altitude páramo habitats) in the Andean fern genera Jamesonia and Eriosorus. We construct time-calibrated phylogenies for the Jamesonia-Eriosorus clade. We then use recent phylogenetic comparative methods to test for evolutionary transitions among habitats, associations between habitat and leaf morphology, and ecologically driven variation in the rate of morphological evolution. Páramo species (Jamesonia) display morphological adaptations consistent with convergent evolution in response to the demands of a highly exposed environment but these adaptations are associated with microhabitat use rather than the páramo per se. Species that are associated with exposed microhabitats (including Jamesonia and Eriorsorus) are characterized by many but short pinnae per frond whereas species occupying sheltered microhabitats (primarily Eriosorus) have few but long pinnae per frond. Pinnae length declines more rapidly with altitude in sheltered species. Rates of speciation are significantly higher among páramo than non-páramo lineages supporting the hypothesis of adaptation and divergence in the unique Páramo biodiversity hotspot.

Forensically important flesh fly species in Thailand: morphology and developmental rate.

PubMed

Sukontason, Kom; Bunchu, Nophawan; Chaiwong, Tarinee; Moophayak, Kittikhun; Sukontason, Kabkaew L

2010-04-01

Forensically important flesh fly species in Thailand have been investigated for their larval morphology and developmental rate to increase the forensic entomology database in Thailand and nearby countries. Sarcophaga (Liosarcophaga) dux Thomson, Sarcophaga (Liopygia) ruficornis (Fabricius), and Sarcophaga (Boettcherisca) peregrina (Robineau-Desvoidy) are the species of greatest forensic importance. The third instars of these species are similar in morphological appearance, making it difficult or impossible to differentiate between them based on external morphological characteristics. This study compares these important characteristics and reveals that the most distinctive is the posterior spiracle, followed by the number of papillae on the anterior spiracle. For confirmation of these species, the unique characteristics of adult males are also shown for accurate identification. Both the third instar and adult male characteristics are keys to identifying these species. In addition, the developmental rate of S. dux was examined in northern Thailand during 2002-2003 under natural ambient temperature (approximately 24-28 degrees C) and a natural light/dark photoperiod (approximately 12:12 h), indicating relatively rapid larval development in summer (March-June), pre-pupae (stop moving) initiated at 72 h. In the rainy season (July-October), pre-pupae initiated at 72 or 96 h, whereas pre-pupae initiated at 96 h in winter.

Loss of YABBY2-Like Gene Expression May Underlie the Evolution of the Laminar Style in Canna and Contribute to Floral Morphological Diversity in the Zingiberales.

PubMed

Morioka, Kelsie; Yockteng, Roxana; Almeida, Ana M R; Specht, Chelsea D

2015-01-01

The Zingiberales is an order of tropical monocots that exhibits diverse floral morphologies. The evolution of petaloid, laminar stamens, staminodes, and styles contributes to this diversity. The laminar style is a derived trait in the family Cannaceae and plays an important role in pollination as its surface is used for secondary pollen presentation. Previous work in the Zingiberales has implicated YABBY2-like genes, which function in promoting laminar outgrowth, in the evolution of stamen morphology. Here, we investigate the evolution and expression of Zingiberales YABBY2-like genes in order to understand the evolution of the laminar style in Canna. Phylogenetic analyses show that multiple duplication events have occurred in this gene lineage prior to the diversification of the Zingiberales. Reverse transcription-PCR in Canna, Costus, and Musa reveals differential expression across floral organs, taxa, and gene copies, and a role for YABBY2-like genes in the evolution of the laminar style is proposed. Selection tests indicate that almost all sites in conserved domains are under purifying selection, consistent with their functional relevance, and a motif unique to monocot YABBY2-like genes is identified. These results contribute to our understanding of the molecular mechanisms underlying the evolution of floral morphologies.

Loss of YABBY2-Like Gene Expression May Underlie the Evolution of the Laminar Style in Canna and Contribute to Floral Morphological Diversity in the Zingiberales

PubMed Central

Morioka, Kelsie; Yockteng, Roxana; Almeida, Ana M. R.; Specht, Chelsea D.

2015-01-01

The Zingiberales is an order of tropical monocots that exhibits diverse floral morphologies. The evolution of petaloid, laminar stamens, staminodes, and styles contributes to this diversity. The laminar style is a derived trait in the family Cannaceae and plays an important role in pollination as its surface is used for secondary pollen presentation. Previous work in the Zingiberales has implicated YABBY2-like genes, which function in promoting laminar outgrowth, in the evolution of stamen morphology. Here, we investigate the evolution and expression of Zingiberales YABBY2-like genes in order to understand the evolution of the laminar style in Canna. Phylogenetic analyses show that multiple duplication events have occurred in this gene lineage prior to the diversification of the Zingiberales. Reverse transcription-PCR in Canna, Costus, and Musa reveals differential expression across floral organs, taxa, and gene copies, and a role for YABBY2-like genes in the evolution of the laminar style is proposed. Selection tests indicate that almost all sites in conserved domains are under purifying selection, consistent with their functional relevance, and a motif unique to monocot YABBY2-like genes is identified. These results contribute to our understanding of the molecular mechanisms underlying the evolution of floral morphologies. PMID:26734021

Morphology and Evolution of Sublimation Pits on Pluto

NASA Astrophysics Data System (ADS)

Abu-Hashmeh, N.; Conrad, J. W.; Nimmo, F.; Moore, J. M.; Stern, A.; Olkin, C.; Weaver, H. A., Jr.; Ennico Smith, K.; Young, L. A.

2017-12-01

Pluto's Sputnik Planitia region hosts a geologically young surface of nitrogen ice that exhibits striking pitted terrain (Moore et al., Science 351, 2016). These pits are most likely formed by sublimation due to incident sunlight, similar to the southern polar cap of Mars (Byrne and Ingersoll, Science 299, 2003); however, their evolution over time has resulted in unique morphological characteristics. Motivated by this, we used the high-resolution mosaic strips captured by New Horizons' Long Range Reconnaissance Imager (LORRI) to map sublimation pits in the southernmost region of Sputnik Planitia. Statistical data shows pit orientations appearing North-South dominant; their morphology also indicates extensional evolution along the major axis caused by further sublimation and contact-coalescence processes. Qualitative analysis of the region yielded indications of an evolutionary path for individual pits that coalesce into each other and exhibit an elongated end-stage. Additionally, densely-pitted regions generally appear to correlate with regions containing longer pits, implying that coalescence may be an important process for elongation. We also model the evolution geometry through competing effects of diffusion (viscous relaxation) and retreat (sublimation) (Buhler and Ingersoll, LPSC Abstract #1746, 2017). The model demonstrates single-pit and coalescing-pit evolutions that influence overall length, as well as a potential ability for the pit center to move in space while the pit morphology evolves.

The Role of Surface Chemistry in Adhesion and Wetting of Gecko Toe Pads

NASA Astrophysics Data System (ADS)

Badge, Ila; Stark, Alyssa Y.; Paoloni, Eva L.; Niewiarowski, Peter H.; Dhinojwala, Ali

2014-10-01

An array of micron-sized setal hairs offers geckos a unique ability to walk on vertical surfaces using van der Waals interactions. Although many studies have focused on the role of surface morphology of the hairs, very little is known about the role of surface chemistry on wetting and adhesion. We expect that both surface chemistry and morphology are important, not only to achieve optimum dry adhesion but also for increased efficiency in self-cleaning of water and adhesion under wet conditions. Here, we used a plasma-based vapor deposition process to coat the hairy patterns on gecko toe pad sheds with polar and non-polar coatings without significantly perturbing the setal morphology. By a comparison of wetting across treatments, we show that the intrinsic surface of gecko setae has a water contact angle between 70-90°. As expected, under wet conditions, adhesion on a hydrophilic surface (glass) was lower than that on a hydrophobic surface (alkyl-silane monolayer on glass). Surprisingly under wet and dry conditions the adhesion was comparable on the hydrophobic surface, independent of the surface chemistry of the setal hairs. This work highlights the need to utilize morphology and surface chemistry in developing successful synthetic adhesives with desirable adhesion and self-cleaning properties.

Self-assembly of red-blood-cell-like (NH4)[Fe2(OH)(PO4)2]·2H2O architectures from 2D nanoplates by sonochemical method.

PubMed

Wu, Kaipeng; Liu, Diwei; Tang, Yun

2018-01-01

Red-blood-cell-like (RBC-like) (NH 4 )[Fe 2 (OH)(PO 4 ) 2 ]·2H 2 O architectures assembled from 2D nanoplates are successfully synthesized via a facile sonochemical method. XRD measurement indicates that the as-prepared sample is well crystallized with a monoclinic structure. The morphology of the sample is characterized by SEM analysis, which shows that the (NH 4 )[Fe 2 (OH)(PO 4 ) 2 ]·2H 2 O particles exhibit a unique biconcave red blood cell morphology with an average diameter of 4um and thickness of 1.5um. The detailed time-dependent experiments are conducted to investigate the morphological evolution process. It reveals that the ultrasonic time is crucial to the morphology of the products, and the RBC-like (NH 4 )[Fe 2 (OH)(PO 4 ) 2 ]·2H 2 O proceeds in steps of crystallization, formation of thin plates, and the subsequent self-assembly. Compared to the available methods that are typically time-consuming and complicated, this smart sonochemical strategy proposed herein is efficient and simple. Moreover, these obtained special RBC-like architectures will be more fascinating for application in many areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Promoting Morphology with a Favorable Density of States Using Diiodooctane to Improve Organic Photovoltaic Device Efficiency and Charge Carrier Lifetimes

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

Garner, Logan E.; Bera, Abhijit; Larson, Bryon W.

Due to the inherent challenges in probing nanoscale properties within bulk heterojunction (BHJ) active layers of organic photovoltaic (OPV) devices, the relationship between morphology and nanoscale electronic structure is not well understood. Here, we employ scanning tunneling microscopy (STM) dI/dV imaging and localized density of states (DOS) spectra to investigate the influence of additives on morphology in a high-performance OPV system. In short, we are able to correlate the use of diiodooctane (DIO) additive with significant changes to the distribution of the localized DOS, most notably a broader distribution of PCE10 polymer HOMO levels and PC70BM fullerene LUMO levels, asmore » well as significantly smaller domain sizes and significantly higher overall device efficiencies. We further correlate this data with a nearly 3-fold increase in charge carrier lifetimes in the active layer when DIO is employed, determined by time-resolved microwave conductivity (TRMC) measurements. In conclusion, the results are consistent with the growing body of literature evidence that DIO promotes the formation of a polymer/fullerene mixed phase and therefore highlight the unique information that this combination of techniques can provide when investigating OPV active layer morphology.« less

Micellar Self-Assembly of Recombinant Resilin-/Elastin-Like Block Copolypeptides.

PubMed

Weitzhandler, Isaac; Dzuricky, Michael; Hoffmann, Ingo; Garcia Quiroz, Felipe; Gradzielski, Michael; Chilkoti, Ashutosh

2017-08-14

Reported here is the synthesis of perfectly sequence defined, monodisperse diblock copolypeptides of hydrophilic elastin-like and hydrophobic resilin-like polypeptide blocks and characterization of their self-assembly as a function of structural parameters by light scattering, cryo-TEM, and small-angle neutron scattering. A subset of these diblock copolypeptides exhibit lower critical solution temperature and upper critical solution temperature phase behavior and self-assemble into spherical or cylindrical micelles. Their morphologies are dictated by their chain length, degree of hydrophilicity, and hydrophilic weight fraction of the ELP block. We find that (1) independent of the length of the corona-forming ELP block there is a minimum threshold in the length of the RLP block below which self-assembly does not occur, but that once that threshold is crossed, (2) the RLP block length is a unique molecular parameter to independently tune self-assembly and (3) increasing the hydrophobicity of the corona-forming ELP drives a transition from spherical to cylindrical morphology. Unlike the self-assembly of purely ELP-based block copolymers, the self-assembly of RLP-ELPs can be understood by simple principles of polymer physics relating hydrophilic weight fraction and polymer-polymer and polymer-solvent interactions to micellar morphology, which is important as it provides a route for the de novo design of desired nanoscale morphologies from first principles.

Amazonis Planitia

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site] (Released 5 July 2002) This is an image of a crater within part of Amazonis Planitia, located at 22.9N, 152.5W. This image features a number of common features exhibited by Martian craters. The crater is sufficiently large to exhibit a central peak that is seen in the upper right hand corner if the image. Also apparent is the slump blocks on the inside of the crater walls. When the crater was first formed, the crater walls were unstable and subsequently formed a series of landslides over time that formed the hummocky terrain just inside the present crater wall. While these cratering features are common to craters formed on other planetary bodies, such as the moon, the ejecta blanket surrounding the crater displays a morphology that is more unique to Mars. The lobate morphology implies that the ejecta blanket was emplaced in an almost fluid fashion rather than the traditional ballistic ejecta emplacement. This crater morphology occurs on Mars where water ice is suspected to be present just beneath the surface. The impact that created the crater would have enough energy to melt large amounts of water that could form the mud or debris flows that characterize the ejecta morphology that is seen in this image.

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

McCormac, Kathleen; Byrd, Ian; Brannen, Rodney

We prepared highly porous Si/TiO 2 composite nanofibres using a unique sulphur-templating method combined with electrospinning. The structure, morphology, surface area, phase and composition of these nanofibres were characterized using Raman spectroscopy, scanning electron microscopy, powder X-ray diffraction, surface area analyser and thermogravimetric analyser. The specific surface area of Si/TiO 2 porous NFs is as large as 387m 2g -1, whose silicon capacity can be maintained above 1580mAhg -1 in 180 cycles.

Investigations into the Origins of the Physical Structure of Thin Films.

DTIC Science & Technology

1985-10-25

part of a Bachelor of Engineering thesis (see publications list). The digitization and grey-level scheme for recording the images was relatively low...Santa Rosa, CA). THESIS Ammar Kouki, Bachelor of Engineering Science (May, 1985), ’Can the Morphology of Thin Films Grown by CVD Be Explained Using...unique to the deposition technique but has been found in all vapor-deposited films as well as electrodeposited films. The only common link between

Constraining climatic controls on hillslope dynamics using a coupled model for the transport of soil and tracers: Application to loess-mantled hillslopes, Charwell River, South Island, New Zealand

Treesearch

J.J. Roering; P. Almond; P. Tonkin; J. McKean

2004-01-01

Landscapes reflect a legacy of tectonic and climatic forcing as modulated by surface processes. Because the morphologic characteristics of landscapes often do not allow us to uniquely define the relative roles of tectonic deformation and climate, additional constraints are required to interpret and predict landscape dynamics. Here we describe a coupled model for the...

Morphology, gas exchange, and chlorophyll content of longleaf pine seedlings in response to rooting volume, copper root pruning, and nitrogen supply in a container nursery

Treesearch

R. Kasten Dumroese; Shi-Jean Susana Sung; Jeremiah R. Pinto; Amy Ross-Davis; D. Andrew Scott

2013-01-01

Few pine species develop a seedling grass stage; this growth phase, characterized by strong, carrot-like taproots and a stem-less nature, poses unique challenges during nursery production. Fertilization levels beyond optimum could result in excessive diameter growth that reduces seedling quality as measured by the root bound index (RBI). We grew longleaf pine (Pinus...