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.

Whole-Cell Chloride Currents in Rat Astrocytes Accompany Changes in Cell Morphology

PubMed Central

Lascola, Christopher D.; Kraig, Richard P.

2009-01-01

Astrocytes can change shape dramatically in response to increased physiological and pathological demands, yet the functional consequences of morphological change are unknown. We report the expression of Cl− currents after manipulations that alter astrocyte morphology. Whole-cell Cl− currents were elicited after (1) rounding up cells by brief exposure to trypsin; (2) converting cells from a flat polygonal to a process-bearing (stellate) morphology by exposure to serum-free Ringer’s solution; and (3) swelling cells by exposure to hypo-osmotic solution. Zero-current potentials approximated the Nernst for Cl−, and rectification usually followed that predicted by the constant-field equation. We observed heterogeneity in the activation and inactivation kinetics, as well as in the relative degree of outward versus inward rectification. Cl− conductances were inhibited by 4,4-diisothiocyanostilbene-2,2′-disulfonic acid (200 μM) and by Zn2+ (1 mM). Whole-cell Cl− currents were not expressed in cells without structural change. We investigated whether changes in cytoskeletal actin accompanying changes in astrocytic morphology play a role in the induction of shape-dependent Cl− currents. Cytochalasins, which disrupt actin polymers by enhancing actin-ATP hydrolysis, elicited whole-cell Cl− conductances in flat, polygonal astrocytes. In stellate cells, elevated intracellular Ca2+ (2 μM), which can depolymerize actin, enhanced Cl− currents, and high intracellular ATP (5 mM), required for repolymerization, reduced Cl− currents. Modulation of Cl− current by Ca2+ and ATP was blocked by concurrent whole-cell dialysis with phalloidin and DNase, respectively. Phalloidin stabilizes actin polymers and DNase inhibits actin polymerization. Dialysis with phalloidin also prevented hypo-osmotically activated Cl− currents. These results demonstrate how the expression of astrocyte Cl− currents can be dependent on cell morphology, the structure of actin, Ca2+ homeostasis, and metabolism. PMID:8786429

Relating structure with morphology: A comparative study of perfect Langmuir Blodgett multilayers

NASA Astrophysics Data System (ADS)

Mukherjee, Smita; Datta, Alokmay; Giglia, Angelo; Mahne, Nichole; Nannarone, Stefano

2008-01-01

Atomic force microscopy and X-ray reflectivity of metal-stearate (MSt) Langmuir-Blodgett films on hydrophilic Silicon (1 0 0), show dramatic reduction in 'pinhole' defects when metal M is changed from Cd to Co, along with excellent periodicity in multilayer, with hydrocarbon tails tilted 9.6° from vertical for CoSt (untilted for CdSt). Near edge X-ray absorption fine structure (NEXAFS) and Fourier transform infra-red (FTIR) spectroscopies indicate bidentate bridging metal-carboxylate coordination in CoSt (unidentate in CdSt), underscoring role of headgroup structure in determining morphology. FTIR studies also show increased packing density in CoSt, consistent with increased coverage.

Cell-Cell Contact Area Affects Notch Signaling and Notch-Dependent Patterning.

PubMed

Shaya, Oren; Binshtok, Udi; Hersch, Micha; Rivkin, Dmitri; Weinreb, Sheila; Amir-Zilberstein, Liat; Khamaisi, Bassma; Oppenheim, Olya; Desai, Ravi A; Goodyear, Richard J; Richardson, Guy P; Chen, Christopher S; Sprinzak, David

2017-03-13

During development, cells undergo dramatic changes in their morphology. By affecting contact geometry, these morphological changes could influence cellular communication. However, it has remained unclear whether and how signaling depends on contact geometry. This question is particularly relevant for Notch signaling, which coordinates neighboring cell fates through direct cell-cell signaling. Using micropatterning with a receptor trans-endocytosis assay, we show that signaling between pairs of cells correlates with their contact area. This relationship extends across contact diameters ranging from micrometers to tens of micrometers. Mathematical modeling predicts that dependence of signaling on contact area can bias cellular differentiation in Notch-mediated lateral inhibition processes, such that smaller cells are more likely to differentiate into signal-producing cells. Consistent with this prediction, analysis of developing chick inner ear revealed that ligand-producing hair cell precursors have smaller apical footprints than non-hair cells. Together, these results highlight the influence of cell morphology on fate determination processes. Copyright © 2017 Elsevier Inc. All rights reserved.

Cell-cell contact area affects Notch signaling and Notch-dependent patterning

PubMed Central

Shaya, Oren; Binshtok, Udi; Hersch, Micha; Rivkin, Dmitri; Weinreb, Sheila; Amir-Zilberstein, Liat; Khamaisi, Bassma; Oppenheim, Olya; Desai, Ravi A.; Goodyear, Richard J.; Richardson, Guy P.; Chen, Christopher S.; Sprinzak, David

2017-01-01

Summary During development, cells undergo dramatic changes in their morphology. By affecting contact geometry, these morphological changes could influence cellular communication. However, it has remained unclear whether and how signaling depends on contact geometry. This question is particularly relevant for Notch signaling, which coordinates neighboring cell fates through direct cell-cell signaling. Using micropatterning with a receptor trans-endocytosis assay, we show that signaling between pairs of cells correlates with their contact area. This relationship extends across contact diameters ranging from microns to tens of microns. Mathematical modeling predicts that dependence of signaling on contact area can bias cellular differentiation in Notch-mediated lateral inhibition processes, such that smaller cells are more likely to differentiate into signal-producing cells. Consistent with this prediction, analysis of developing chick inner ear revealed that ligand-producing hair cell precursors have smaller apical footprints than non-hair cells. Together, these results highlight the influence of cell morphology on fate determination processes. PMID:28292428

From tunable core-shell nanoparticles to plasmonic drawbridges: Active control of nanoparticle optical properties

PubMed Central

Byers, Chad P.; Zhang, Hui; Swearer, Dayne F.; Yorulmaz, Mustafa; Hoener, Benjamin S.; Huang, Da; Hoggard, Anneli; Chang, Wei-Shun; Mulvaney, Paul; Ringe, Emilie; Halas, Naomi J.; Nordlander, Peter; Link, Stephan; Landes, Christy F.

2015-01-01

The optical properties of metallic nanoparticles are highly sensitive to interparticle distance, giving rise to dramatic but frequently irreversible color changes. By electrochemical modification of individual nanoparticles and nanoparticle pairs, we induced equally dramatic, yet reversible, changes in their optical properties. We achieved plasmon tuning by oxidation-reduction chemistry of Ag-AgCl shells on the surfaces of both individual and strongly coupled Au nanoparticle pairs, resulting in extreme but reversible changes in scattering line shape. We demonstrated reversible formation of the charge transfer plasmon mode by switching between capacitive and conductive electronic coupling mechanisms. Dynamic single-particle spectroelectrochemistry also gave an insight into the reaction kinetics and evolution of the charge transfer plasmon mode in an electrochemically tunable structure. Our study represents a highly useful approach to the precise tuning of the morphology of narrow interparticle gaps and will be of value for controlling and activating a range of properties such as extreme plasmon modulation, nanoscopic plasmon switching, and subnanometer tunable gap applications. PMID:26665175

Tipping points in Anthropocene fluvial dynamics

NASA Astrophysics Data System (ADS)

Notebaert, Bastiaan; Broothaerts, Nils; Verstraeten, Gert; Berger, Jean-François; Houbrechts, Geoffrey

2016-04-01

Many rivers have undergone dramatic changes over the last millennia due to anthropogenic on- and offsite impacts. These changes have important implications for the geomorphic and hydrological functioning of the river. In this study we compare the influence of large-scaled off-site anthropogenic impact on three European river systems. We do this using traditional geomorphological methods, combined with palynological and archaeological data; for each catchment a Holocene sediment budget was constructed. The Dijle catchment is located in the central Belgian loess belt, and has undergone intense agriculture for at least the last 2000 year. Pre-Anthropocene floodplain are big marshes lacking a well-established river channel. Anthropogenic deforestation in the headwaters resulted in a sediment pulse from the Bronze Age on. In the main floodplain sediments gradually covered the peat layer, starting near a newly formed river channel and expanding over time towards the floodplain edges. In contrast, this transition is abrupt in the smaller tributary floodplains. Comparison with palynological data shows that this abrupt transition occurs when human impact reaches a certain threshold. The Valdaine region is located in the French Pre-Alps. Floodplain deposition increased over time since the Neolithic time period due to human induced and fire related soil erosion. This general aggradation trend is however interrupted by three major river incision phases which are caused by human land abandonment and dry periods. A second major change in floodplain geomorphology occurs during the High Roman Period and the last 800 year: the fine-grained meandering river changes to a gravel loaded braided river. During this period the upstream mountain reaches became a major sediment source due to deforestation, possibly combined with climate change. During the last century reforestation and land abandonment has led to a new incision phases, and floodplain are now a major source of gravel while the river partially maintains its braided pattern. The Amblève River in the Belgian Ardennes uplands underwent less dramatic changes. Large parts of the catchment are deforested during the last 700 years, leading to an increase in floodplain sedimentation. Despite this major sediment pulse, change in floodplain morphology remained limited to an increase in bank height. We argue that a combination of floodplain and channel morphology, the fine texture of supplied sediment and the high stream power of channel forming events result is a system that is less sensitive to change. Also the relative short time of impact may play a role. These three examples demonstrate the varying impact of human deforestation on floodplain geomorphology. For the Dijle and Valdaine region this lead to dramatic changes once a certain tipping point is reached. In contrast the Amblève river is more resilient to human impact due to its specific morphological setting. The morphology of the catchments and the nature of supplied sediments plays a major role in the sensitivity of fluvial systems to environmental impact. Once the tipping points are reached, it is difficult for the river to revert to its original state and floodplains remain highly impacted.

Resolving Electrode Morphology’s Impact on Platinum Group Metal-Free Cathode Performance Using Nano-CT of 3D Hierarchical Pore and Ionomer Distribution

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

Komini Babu, Siddharth; Chung, Hoon T.; Zelenay, Piotr

This paper reports on the characterization of polymer electrolyte fuel cell (PEFC) cathodes featuring a platinum group metal-free (PGM-free) catalyst using nano-scale resolution X-ray computed tomography (nano-CT) and morphological analysis. PGM-free PEFC cathodes have gained significant interest in the past decade since they have the potential to dramatically reduce PEFC costs by eliminating the large platinum (Pt) raw material cost. However, several challenges remain before they are commercially viable. Since these catalysts have lower volumetric activity, the PGM-free cathodes are thicker and are subject to increased gas and proton transport resistances that reduce the performance. To better understand the efficacymore » of the catalyst and improve electrode performance, a detailed understanding the correlation between electrode fabrication, morphology, and performance is crucial. In this work, the pore/solid structure and the ionomer distribution was resolved in three dimensions (3D) using nano-CT for three PGM-free electrodes of varying Nafion® loading. The associated transport properties were evaluated from pore/particlescale simulations within the nano-CT imaged structure. These characterizations are then used to elucidate the microstructural origins of the dramatic changes in fuel cell performance with varying Nafion® ionomer loading. We show that this is primarily a result of distinct changes in ionomer’s spatial distribution. The significant impact of electrode morphology on performance highlights the importance of PGM-free electrode development in concert with efforts to improve catalyst activity and durability.« less

Resolving Electrode Morphology’s Impact on Platinum Group Metal-Free Cathode Performance Using Nano-CT of 3D Hierarchical Pore and Ionomer Distribution

DOE PAGES

Komini Babu, Siddharth; Chung, Hoon T.; Zelenay, Piotr; ...

2016-11-02

This paper reports on the characterization of polymer electrolyte fuel cell (PEFC) cathodes featuring a platinum group metal-free (PGM-free) catalyst using nano-scale resolution X-ray computed tomography (nano-CT) and morphological analysis. PGM-free PEFC cathodes have gained significant interest in the past decade since they have the potential to dramatically reduce PEFC costs by eliminating the large platinum (Pt) raw material cost. However, several challenges remain before they are commercially viable. Since these catalysts have lower volumetric activity, the PGM-free cathodes are thicker and are subject to increased gas and proton transport resistances that reduce the performance. To better understand the efficacymore » of the catalyst and improve electrode performance, a detailed understanding the correlation between electrode fabrication, morphology, and performance is crucial. In this work, the pore/solid structure and the ionomer distribution was resolved in three dimensions (3D) using nano-CT for three PGM-free electrodes of varying Nafion® loading. The associated transport properties were evaluated from pore/particlescale simulations within the nano-CT imaged structure. These characterizations are then used to elucidate the microstructural origins of the dramatic changes in fuel cell performance with varying Nafion® ionomer loading. We show that this is primarily a result of distinct changes in ionomer’s spatial distribution. The significant impact of electrode morphology on performance highlights the importance of PGM-free electrode development in concert with efforts to improve catalyst activity and durability.« less

Form matters: morphological aspects of lateral root development

PubMed Central

Szymanowska-Pułka, Joanna

2013-01-01

Background The crucial role of roots in plant nutrition, and consequently in plant productivity, is a strong motivation to study the growth and functioning of various aspects of the root system. Numerous studies on lateral roots, as a major determinant of the root system architecture, mostly focus on the physiological and molecular bases of developmental processes. Unfortunately, little attention is paid either to the morphological changes accompanying the formation of a lateral root or to morphological defects occurring in lateral root primordia. The latter are observed in some mutants and occasionally in wild-type plants, but may also result from application of external factors. Scope and Conclusions In this review various morphological aspects of lateral branching in roots are analysed. Morphological events occurring during the formation of a typical lateral root are described. This process involves dramatic changes in the geometry of the developing organ that at early stages are associated with oblique cell divisions, leading to breaking of the symmetry of the cell pattern. Several types of defects in the morphology of primordia are indicated and described. Computer simulations show that some of these defects may result from an unstable field of growth rates. Significant changes in both primary and lateral root morphology may also be a consequence of various mutations, some of which are auxin-related. Examples reported in the literature are considered. Finally, lateral root formation is discussed in terms of mechanics. In this approach the primordium is considered as a physical object undergoing deformation and is characterized by specific mechanical properties. PMID:24190952

Surface changes of biopolymers PHB and PLLA induced by Ar+ plasma treatment and wet etching

NASA Astrophysics Data System (ADS)

Slepičková Kasálková, N.; Slepička, P.; Sajdl, P.; Švorčík, V.

2014-08-01

Polymers, especially group of biopolymers find potential application in a wide range of disciplines due to their biodegradability. In biomedical applications these materials can be used as a scaffold or matrix. In this work, the influence of the Ar+ plasma treatment and subsequent wet etching (acetone/water) on the surface properties of polymers were studied. Two biopolymers - polyhydroxybutyrate with 8% polyhydroxyvalerate (PHB) and poly-L-lactic acid (PLLA) were used in these experiments. Modified surface layers were analyzed by different methods. Surface wettability was characterized by determination of water contact angle. Changes in elemental composition of modified surfaces were performed by X-ray Photoelectron Spectroscopy (XPS). Surface morphology and roughness was examined using Atomic Force Microscopy (AFM). Gravimetry method was used to study the mass loss. It was found that the modification from both with plasma and wet etching leads to dramatic changes of surface properties (surface chemistry, morphology and roughness). Rate of changes of these features strongly depends on the modification parameters.

Parallel behavioral and morphological divergence in fence lizards on two college campuses

PubMed Central

Howe, Stephen; Hynes, Stephanie; Hobbs, Brooke; Handal, Karina

2018-01-01

The spread of urban development has dramatically altered natural habitats, modifying community relationships, abiotic factors, and structural features. Animal populations living in these areas must perish, emigrate, or find ways to adjust to a suite of new selective pressures. Those that successfully inhabit the urban environment may make behavioral, physiological, and/or morphological adjustments that represent either evolutionary change and/or phenotypic plasticity. We tested for effects of urbanization on antipredator behavior and associated morphology across an urban-wild gradient in the western fence lizard (Sceloporus occidentalis) in two California counties, Santa Barbara and San Luis Obispo. We compared college campuses in both counties with adjacent rural habitats, conducting field trials that allowed us to characterize antipredator behavior in response to the acute stress of capture. We found notable divergence between campus and rural behavior, with campus lizards more frequently exhibiting diminished escape behavior, including tonic immobility, and lower sprint speeds. Furthermore, campus females had significantly shorter limbs, and while this did not explain variation in sprint speed, those with shorter limbs were more likely to show tonic immobility. We hypothesize that these parallel behavioral and morphological changes on both campuses reflect adjustment to a novel environment involving changes in predation and human presence. PMID:29444102

Morphological and functional evaluation of chronic pancreatitis with magnetic resonance imaging

PubMed Central

Hansen, Tine Maria; Nilsson, Matias; Gram, Mikkel; Frøkjær, Jens Brøndum

2013-01-01

Magnetic resonance imaging (MRI) techniques for assessment of morphology and function of the pancreas have been improved dramatically the recent years and MRI is very often used in diagnosing and follow-up of chronic pancreatitis (CP) patients. Standard MRI including fat-suppressed T1-weighted and T2-weighted imaging techniques reveal decreased signal and glandular atrophy of the pancreas in CP. In contrast-enhanced MRI of the pancreas in CP the pancreatic signal is usually reduced and delayed due to decreased perfusion as a result of chronic inflammation and fibrosis. Thus, morphological changes of the ductal system can be assessed by magnetic resonance cholangiopancreatography (MRCP). Furthermore, secretin-stimulated MRCP is a valuable technique to evaluate side branch pathology and the exocrine function of the pancreas and diffusion weighted imaging can be used to quantify both parenchymal fibrotic changes and the exocrine function of the pancreas. These standard and advanced MRI techniques are supplementary techniques to reveal morphological and functional changes of the pancreas in CP. Recently, spectroscopy has been used for assessment of metabolite concentrations in-vivo in different tissues and may have the potential to offer better tissue characterization of the pancreas. Hence, the purpose of the present review is to provide an update on standard and advanced MRI techniques of the pancreas in CP. PMID:24259954

Surface Modifications during a Catalytic Reaction: A Combined APT and FIB/SEM Analysis of Surface Segregation

DOE PAGES

Barroo, Cedric; Janvelyan, Nare; Zugic, Branko; ...

2016-07-25

To improve the understanding of catalytic processes, the surface structure and composition of the active materials need to be determined before and after reaction. Morphological changes may occur under reaction conditions and can dramatically influence the reactivity and/or selectivity of a catalyst. Goldbased catalysts with different architectures are currently being developed for selective oxidation reactions at low temperatures. Specifically, nanoporous Au (npAu) with a composition of Au 97-Ag 3 is obtained by dealloying a Ag 70-Au 30 bulk alloy. Recent studies highlight the efficiency of npAu catalysts for methanol oxidation using ozone to activate the catalysts before methanol oxidation. Inmore » this paper, we studied the morphological and compositional changes occurring at the surface of Au-based catalysts in certain conditions.« less

Game-Changing Innovations: How Culture Can Change the Parameters of Its Own Evolution and Induce Abrupt Cultural Shifts.

PubMed

Kolodny, Oren; Creanza, Nicole; Feldman, Marcus W

2016-12-01

One of the most puzzling features of the prehistoric record of hominid stone tools is its apparent punctuation: it consists of abrupt bursts of dramatic change that separate long periods of largely unchanging technology. Within each such period, small punctuated cultural modifications take place. Punctuation on multiple timescales and magnitudes is also found in cultural trajectories from historical times. To explain these sharp cultural bursts, researchers invoke such external factors as sudden environmental change, rapid cognitive or morphological change in the hominids that created the tools, or replacement of one species or population by another. Here we propose a dynamic model of cultural evolution that accommodates empirical observations: without invoking external factors, it gives rise to a pattern of rare, dramatic cultural bursts, interspersed by more frequent, smaller, punctuated cultural modifications. Our model includes interdependent innovation processes that occur at different rates. It also incorporates a realistic aspect of cultural evolution: cultural innovations, such as those that increase food availability or that affect cultural transmission, can change the parameters that affect cultural evolution, thereby altering the population's cultural dynamics and steady state. This steady state can be regarded as a cultural carrying capacity. These parameter-changing cultural innovations occur very rarely, but whenever one occurs, it triggers a dramatic shift towards a new cultural steady state. The smaller and more frequent punctuated cultural changes, on the other hand, are brought about by innovations that spur the invention of further, related, technology, and which occur regardless of whether the population is near its cultural steady state. Our model suggests that common interpretations of cultural shifts as evidence of biological change, for example the appearance of behaviorally modern humans, may be unwarranted.

Game-Changing Innovations: How Culture Can Change the Parameters of Its Own Evolution and Induce Abrupt Cultural Shifts

PubMed Central

2016-01-01

One of the most puzzling features of the prehistoric record of hominid stone tools is its apparent punctuation: it consists of abrupt bursts of dramatic change that separate long periods of largely unchanging technology. Within each such period, small punctuated cultural modifications take place. Punctuation on multiple timescales and magnitudes is also found in cultural trajectories from historical times. To explain these sharp cultural bursts, researchers invoke such external factors as sudden environmental change, rapid cognitive or morphological change in the hominids that created the tools, or replacement of one species or population by another. Here we propose a dynamic model of cultural evolution that accommodates empirical observations: without invoking external factors, it gives rise to a pattern of rare, dramatic cultural bursts, interspersed by more frequent, smaller, punctuated cultural modifications. Our model includes interdependent innovation processes that occur at different rates. It also incorporates a realistic aspect of cultural evolution: cultural innovations, such as those that increase food availability or that affect cultural transmission, can change the parameters that affect cultural evolution, thereby altering the population’s cultural dynamics and steady state. This steady state can be regarded as a cultural carrying capacity. These parameter-changing cultural innovations occur very rarely, but whenever one occurs, it triggers a dramatic shift towards a new cultural steady state. The smaller and more frequent punctuated cultural changes, on the other hand, are brought about by innovations that spur the invention of further, related, technology, and which occur regardless of whether the population is near its cultural steady state. Our model suggests that common interpretations of cultural shifts as evidence of biological change, for example the appearance of behaviorally modern humans, may be unwarranted. PMID:28036346

Extreme Postnatal Scaling in Bat Feeding Performance: A View of Ecomorphology from Ontogenetic and Macroevolutionary Perspectives.

PubMed

Santana, Sharlene E; Miller, Kimberly E

2016-09-01

Ecomorphology studies focus on understanding how anatomical and behavioral diversity result in differences in performance, ecology, and fitness. In mammals, the determinate growth of the skeleton entails that bite performance should change throughout ontogeny until the feeding apparatus attains its adult size and morphology. Then, interspecific differences in adult phenotypes are expected to drive food resource partitioning and patterns of lineage diversification. However, Formal tests of these predictions are lacking for the majority of mammal groups, and thus our understanding of mammalian ecomorphology remains incomplete. By focusing on a fundamental measure of feeding performance, bite force, and capitalizing on the extraordinary morphological and dietary diversity of bats, we discuss how the intersection of ontogenetic and macroevolutionary changes in feeding performance may impact ecological diversity in these mammals. We integrate data on cranial morphology and bite force gathered through longitudinal studies of captive animals and comparative studies of free-ranging individuals. We demonstrate that ontogenetic trajectories and evolutionary changes in bite force are highly dependent on changes in body and head size, and that bats exhibit dramatic, allometric increases in bite force during ontogeny. Interspecific variation in bite force is highly dependent on differences in cranial morphology and function, highlighting selection for ecological specialization. While more research is needed to determine how ontogenetic changes in size and bite force specifically impact food resource use and fitness in bats, interspecific diversity in cranial morphology and bite performance seem to closely match functional differences in diet. Altogether, these results suggest direct ecomorphological relationships at ontogenetic and macroevolutionary scales in bats. © The Author 2016. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Massing in high shear wet granulation can simultaneously improve powder flow and deteriorate powder compaction: a double-edged sword.

PubMed

Shi, Limin; Feng, Yushi; Sun, Changquan Calvin

2011-05-18

The influence of massing during high shear wet granulation (HSWG) process on granule properties and performance was investigated using microcrystalline cellulose (MCC). Massing time varied from 0 to 40 min while other factors were fixed. Granule physical properties, including morphology, size, porosity, and specific surface area (SSA), were characterized. Changes in powder properties were profound in the first 10 min of massing but negligible beyond 10 min. With 10 min of massing, granule tabletability decreased by 75% while flowability increased by 75%. The significantly deteriorated tabletability and improved flowability resulted from dramatic changes in granule morphology, porosity, and SSA. The results confirm that massing time is a key process parameter in HSWG, and it must be carefully evaluated and controlled during process development, scale up, and manufacturing. Copyright © 2011 Elsevier B.V. All rights reserved.

Microarray analysis on gene regulation by estrogen, progesterone and tamoxifen in human endometrial stromal cells.

PubMed

Ren, Chun-E; Zhu, Xueqiong; Li, Jinping; Lyle, Christian; Dowdy, Sean; Podratz, Karl C; Byck, David; Chen, Hai-Bin; Jiang, Shi-Wen

2015-03-13

Epithelial stromal cells represent a major cellular component of human uterine endometrium that is subject to tight hormonal regulation. Through cell-cell contacts and/or paracrine mechanisms, stromal cells play a significant role in the malignant transformation of epithelial cells. We isolated stromal cells from normal human endometrium and investigated the morphological and transcriptional changes induced by estrogen, progesterone and tamoxifen. We demonstrated that stromal cells express appreciable levels of estrogen and progesterone receptors and undergo different morphological changes upon hormonal stimulation. Microarray analysis indicated that both estrogen and progesterone induced dramatic alterations in a variety of genes associated with cell structure, transcription, cell cycle, and signaling. However, divergent patterns of changes, and in some genes opposite effects, were observed for the two hormones. A large number of genes are identified as novel targets for hormonal regulation. These hormone-responsive genes may be involved in normal uterine function and the development of endometrial malignancies.

Automated Techniques for Quantification of Coastline Change Rates using Landsat Imagery along Caofeidian, China

NASA Astrophysics Data System (ADS)

Dong, Di; Li, Ziwei; Liu, Zhaoqin; Yu, Yang

2014-03-01

This paper focuses on automated extraction and monitoring of coastlines by remote sensing techniques using multi-temporal Landsat imagery along Caofeidian, China. Caofeidian, as one of the active economic regions in China, has experienced dramatic change due to enhanced human activities, such as land reclamation. These processes have caused morphological changes of the Caofeidian shoreline. In this study, shoreline extraction and change analysis are researched. An algorithm based on image texture and mathematical morphology is proposed to automate coastline extraction. We tested this approach and found that it's capable of extracting coastlines from TM and ETM+ images with little human modifications. Then, the detected coastline vectors are imported into Arcgis software, and the Digital Shoreline Analysis System (DSAS) is used to calculate the change rate (the end point rate and linear regression rate). The results show that in some parts of the research area, remarkable coastline changes are observed, especially the accretion rate. The abnormal accretion is mostly attributed to the large-scale land reclamation during 2003 and 2004 in Caofeidian. So we can conclude that various construction projects, especially the land reclamation project, have made Caofeidian shorelines change greatly, far above the normal.

Regional stiffening with aging in tibialis anterior tendons of mice occurs independent of changes in collagen fibril morphology

PubMed Central

Wood, Lauren K.; Arruda, Ellen M.

2011-01-01

The incidence of tendon degeneration and rupture increases with advancing age. The mechanisms underlying this increased risk remain unknown but may arise because of age-related changes in tendon mechanical properties and structure. Our purpose was to determine the effect of aging on tendon mechanical properties and collagen fibril morphology. Regional mechanical properties and collagen fibril characteristics were determined along the length of tibialis anterior (TA) tendons from adult (8- to 12-mo-old) and old (28- to 30-mo-old) mice. Tangent modulus of all regions along the tendons increased in old age, but the increase was substantially greater in the proximal region adjacent to the muscle than in the rest of the tendon. Overall end-to-end modulus increased with old age at maximum tendon strain (799 ± 157 vs. 1,419 ± 91 MPa) and at physiologically relevant strain (377 ± 137 vs. 798 ± 104 MPa). Despite the dramatic changes in tendon mechanical properties from adulthood to old age, collagen fibril morphology and packing fraction remained relatively constant in all tendon regions examined. Since tendon properties are influenced by their external loading environment, we also examined the effect of aging on TA muscle contractile properties. Maximum isometric force did not differ between the age groups. We conclude that TA tendons stiffen in a region-dependent manner throughout the life span, but the changes in mechanical properties are not accompanied by corresponding changes in collagen fibril morphology or force-generating capacity of the TA muscle. PMID:21737825

Little evidence for morphological change in a resilient endemic species following the introduction of a novel predator.

PubMed

Sharpe, D M T; Langerhans, R B; Low-Décarie, E; Chapman, L J

2015-11-01

Human activities, such as species introductions, are dramatically and rapidly altering natural ecological processes and often result in novel selection regimes. To date, we still have a limited understanding of the extent to which such anthropogenic selection may be driving contemporary phenotypic change in natural populations. Here, we test whether the introduction of the piscivorous Nile perch, Lates niloticus, into East Africa's Lake Victoria and nearby lakes coincided with morphological change in one resilient native prey species, the cyprinid fish Rastrineobola argentea. Drawing on prior ecomorphological research, we predicted that this novel predator would select for increased allocation to the caudal region in R. argentea to enhance burst-swimming performance and hence escape ability. To test this prediction, we compared body morphology of R. argentea across space (nine Ugandan lakes differing in Nile perch invasion history) and through time (before and after establishment of Nile perch in Lake Victoria). Spatial comparisons of contemporary populations only partially supported our predictions, with R. argentea from some invaded lakes having larger caudal regions and smaller heads compared to R. argentea from uninvaded lakes. There was no clear evidence of predator-associated change in body shape over time in Lake Victoria. We conclude that R. argentea have not responded to the presence of Nile perch with consistent morphological changes and that other factors are driving observed patterns of body shape variation in R. argentea. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Phenotypic and Physiological Characterization of the Epibiotic Interaction Between TM7x and Its Basibiont Actinomyces.

PubMed

Bor, Batbileg; Poweleit, Nicole; Bois, Justin S; Cen, Lujia; Bedree, Joseph K; Zhou, Z Hong; Gunsalus, Robert P; Lux, Renate; McLean, Jeffrey S; He, Xuesong; Shi, Wenyuan

2016-01-01

Despite many examples of obligate epibiotic symbiosis (one organism living on the surface of another) in nature, such an interaction has rarely been observed between two bacteria. Here, we further characterize a newly reported interaction between a human oral obligate parasitic bacterium TM7x (cultivated member of Candidatus Saccharimonas formerly Candidate Phylum TM7), and its basibiont Actinomyces odontolyticus species (XH001), providing a model system to study epiparasitic symbiosis in the domain Bacteria. Detailed microscopic studies indicate that both partners display extensive morphological changes during symbiotic growth. XH001 cells manifested as short rods in monoculture, but displayed elongated and hyphal morphology when physically associated with TM7x. Interestingly, these dramatic morphological changes in XH001 were also induced in oxygen-depleted conditions, even in the absence of TM7x. Targeted quantitative real-time PCR (qRT-PCR) analyses revealed that both the physical association with TM7x as well as oxygen depletion triggered up-regulation of key stress response genes in XH001, and in combination, these conditions act in an additive manner. TM7x and XH001 co-exist with relatively uniform cell morphologies under nutrient-replete conditions. However, upon nutrient depletion, TM7x-associated XH001 displayed a variety of cell morphologies, including swollen cell body, clubbed-ends, and even cell lysis, and a large portion of TM7x cells transformed from ultrasmall cocci into elongated cells. Our study demonstrates a highly dynamic interaction between epibiont TM7x and its basibiont XH001 in response to physical association or environmental cues such as oxygen level and nutritional status, as reflected by their morphological and physiological changes during symbiotic growth.

[Banff score changes in kidneys from marginal donors].

PubMed

Borda, Bernadett; Szederkényi, Edit; Ottlakán, Aurél; Kemény, Éva; Szabó, Viktor; Hódi, Zoltán; Lázár, György

2016-02-21

Despite an increase in the number of cadaver donors and the number of overall organ transplantations, the dramatic increase in the waiting list makes it necessary to reconsider donor criteria. The authors examined whether differences could exist in the function and/or morphology of transplanted kidneys originated from marginal and ideal donors one and five years after transplantation. Kidney function and histopathologic findings were analysed and compared one and 5 years after transplantation in 97 patients having marginal donor kidneys and 178 patients who received ideal donor kidneys. Serum creatinine level was significantly higher (p = 0.0001) and estimated glomerular filtration rate was significantly lower (p = 0.003) in patients having marginal donor kidneys as compared to those with ideal donor kidneys 5 years after transplantation. Morphological changes in the transplanted kidneys such as tubulitis (p = 0.014) and interstitial inflammation (p = 0.025) were significantly more frequently present in patients with marginal donor kidneys than in those with ideal donor kidneys one year after transplantation. Despite an absence of differences in kidney function one year after kidney transplantation between patients having marginal and ideal donor kidneys, morphologic differences in the transplanted kidneys can be detected between the two groups of patients.

Modular evolution of the Cetacean vertebral column.

PubMed

Buchholtz, Emily A

2007-01-01

Modular theory predicts that hierarchical developmental processes generate hierarchical phenotypic units that are capable of independent modification. The vertebral column is an overtly modular structure, and its rapid phenotypic transformation in cetacean evolution provides a case study for modularity. Terrestrial mammals have five morphologically discrete vertebral series that are now known to be coincident with Hox gene expression patterns. Here, I present the hypothesis that in living Carnivora and Artiodactyla, and by inference in the terrestrial ancestors of whales, the series are themselves components of larger precaudal and caudal modular units. Column morphology in a series of fossil and living whales is used to predict the type and sequence of developmental changes responsible for modification of that ancestral pattern. Developmental innovations inferred include independent meristic additions to the precaudal column in basal archaeocetes and basilosaurids, stepwise homeotic reduction of the sacral series in protocetids, and dissociation of the caudal series into anterior tail and fluke subunits in basilosaurids. The most dramatic change was the novel association of lumbar and anterior caudal vertebrae in a module that crosses the precaudal/caudal boundary. This large unit is defined by shared patterns of vertebral morphology, count, and size in all living whales (Neoceti).

Evolution in an extreme environment: developmental biases and phenotypic integration in the adaptive radiation of antarctic notothenioids.

PubMed

Hu, Yinan; Ghigliotti, Laura; Vacchi, Marino; Pisano, Eva; Detrich, H William; Albertson, R Craig

2016-06-29

Over the past 40 million years water temperatures have dramatically dropped in the Southern Ocean, which has led to the local extinction of most nearshore fish lineages. The evolution of antifreeze glycoproteins in notothenioids, however, enabled these ancestrally benthic fishes to survive and adapt as temperatures reached the freezing point of seawater (-1.86 °C). Antarctic notothenioids now represent the primary teleost lineage in the Southern Ocean and are of fundamental importance to the local ecosystem. The radiation of notothenioids has been fostered by the evolution of "secondary pelagicism", the invasion of pelagic habitats, as the group diversified to fill newly available foraging niches in the water column. While elaborate craniofacial modifications have accompanied this adaptive radiation, little is known about how these morphological changes have contributed to the evolutionary success of notothenioids. We used a 3D-morphometrics approach to investigate patterns of morphological variation in the craniofacial skeleton among notothenioids, and show that variation in head shape is best explained by divergent selection with respect to foraging niche. We document further an accelerated rate of morphological evolution in the icefish family Channichthyidae, and show that their rapid diversification was accompanied by the evolution of relatively high levels of morphological integration. Whereas most studies suggest that extensive integration should constrain phenotypic evolution, icefish stand out as a rare example of increased integration possibly facilitating evolutionary potential. Finally, we show that the unique feeding apparatus in notothenioids in general, and icefish in particular, can be traced to shifts in early developmental patterning mechanisms and ongoing growth of the pharyngeal skeleton. Our work suggests that ecological opportunity is a major factor driving craniofacial variation in this group. Further, the observation that closely related lineages can differ dramatically in integration suggests that this trait can evolve quickly. We propose that the evolution of high levels of phenotypic integration in icefishes may be considered a key innovation that facilitated their morphological evolution and subsequent ecological expansion.

Fluid Mechanical Properties of Silkworm Fibroin Solutions

NASA Astrophysics Data System (ADS)

Matsumoto, Akira

2005-11-01

The aqueous solution behavior of silk fibroin is of interest due to the assembly and processing of this protein related to the spinning of protein fibers that exhibit remarkable mechanical properties. To gain insight into the origins of this functional feature, it is desired to determine how the protein behaves under a range of solution conditions. Pure fibroin at different concentrations in water was studied for surface tension, as a measure of surfactancy. In addition, shear induced changes on these solutions in terms of structure and morphology was also determined. Fibroin solutions exhibited shear rate-sensitive viscosity changes and precipitated at a critical shear rate where a dramatic increase of 75-150% of the initial value was observed along with a decrease in viscosity. In surface tension measurements, critical micelle concentrations were in the range of 3-4% w/v. The influence of additional factors, such as sericin protein, divalent and monovalent cations, and pH on the solution behavior in relation to structural and morphological features will also be described.

Exploring Solvent Shape and Function Using - and Isomer-Selective Vibrational Spectroscopy

NASA Astrophysics Data System (ADS)

Johnson, Mark

2010-06-01

We illustrate the new types of information than can be obtained through isomer-selective ``hole-burning'' spectroscopy carried out in the vibrational manifolds of Ar-tagged cluster ions. Three examples of increasing complexity will be presented where the changes in a solute ion are correlated with different morphologies of a surrounding solvent cage. In the first, we discuss the weak coupling limit where different hydration morphologies lead to small distortions of a covalent ion. We then introduce the more interesting case of the hydrated electron, where different shapes of the water network lead to dramatic changes in the extent of delocalization in the diffuse excess electron cloud. We then turn to the most complex case involving hydration of the nitrosonium ion, where different arrangements of the same number of water molecules span the range in behavior from simple solvation to actively causing a chemical reaction. The latter results are particularly interesting as they provide a microscopic, molecular-level picture of the ``solvent coordinate'' commonly used to describe solvent mediated processes.

Effects of morphology on the radiative properties of internally mixed light absorbing carbon aerosols with different aging status.

PubMed

Cheng, Tianhai; Wu, Yu; Chen, Hao

2014-06-30

Light absorbing carbon aerosols play a substantial role in climate change through radiative forcing, which is the dominant absorber of solar radiation. Radiative properties of light absorbing carbon aerosols are strongly dependent on the morphological factors and the mixing mechanism of black carbon with other aerosol components. This study focuses on the morphological effects on the optical properties of internally mixed light absorbing carbon aerosols using the numerically exact superposition T-matrix method. Three types aerosols with different aging status such as freshly emitted BC particles, thinly coated light absorbing carbon aerosols, heavily coated light absorbing carbon aerosols are studied. Our study showed that morphological factors change with the aging of internally mixed light absorbing carbon aerosols to result in a dramatic change in their optical properties. The absorption properties of light absorbing carbon aerosols can be enhanced approximately a factor of 2 at 0.67 um, and these enhancements depend on the morphological factors. A larger shell/core diameter ratio of volume-equivalent shell-core spheres (S/C), which indicates the degree of coating, leads to stronger absorption. The enhancement of absorption properties accompanies a greater enhancement of scattering properties, which is reflected in an increase in single scattering albedo (SSA). The enhancement of single scattering albedo due to the morphological effects can reach a factor of 3.75 at 0.67 μm. The asymmetry parameter has a similar yet smaller enhancement. Moreover, the corresponding optical properties of shell-and-core model determined by using Lorenz -Mie solutions are presented for comparison. We found that the optical properties of internally mixed light absorbing carbon aerosol can differ fundamentally from those calculated for the Mie theory shell-and-core model, particularly for thinly coated light absorbing carbon aerosols. Our studies indicate that the complex morphology of internally mixed light absorbing carbon aerosols must be explicitly considered in climate radiation balance.

Ordered polymer nanofibers enhance output brightness in bilayer light-emitting field-effect transistors.

PubMed

Hsu, Ben B Y; Seifter, Jason; Takacs, Christopher J; Zhong, Chengmei; Tseng, Hsin-Rong; Samuel, Ifor D W; Namdas, Ebinazar B; Bazan, Guillermo C; Huang, Fei; Cao, Yong; Heeger, Alan J

2013-03-26

Polymer light emitting field effect transistors are a class of light emitting devices that reveal interesting device physics. Device performance can be directly correlated to the most fundamental polymer science. Control over surface properties of the transistor dielectric can dramatically change the polymer morphology, introducing ordered phase. Electronic properties such as carrier mobility and injection efficiency on the interface can be promoted by ordered nanofibers in the polymer. Moreover, by controlling space charge in the polymer interface, the recombination zone can be spatially extended and thereby enhance the optical output.

Along-axis variations in seafloor spreading in the MARK area

NASA Astrophysics Data System (ADS)

Karson, J. A.; Thompson, G.; Humphris, S. E.; Bryan, W. B.; Edmond, J. M.

1987-08-01

Recent investigations with the manned submersible Alvin and the Angus deep-towed camera sled greatly extended the known range of variations in the style of seafloor spreading along the axis of the Mid-Atlantic Ridge. Five transects of the spreading center at intervals of 10-20 km south of the Kane Fracture Zone at 24 deg N latitude demonstate dramatic changes in the style and magnitude of tectonic extension, development of the neovolcanic zone, expression of hydrothermal venting, types of lithologic exposures, and morphology of the median valley.

Research on M23C6 precipitation of 690 alloy

NASA Astrophysics Data System (ADS)

Zhigang, Song; han, Feng; Wenjie, Zheng; Lihong, Zhang; Mingjuan, Ma; Weijun, Sang

Precipitation M23C6 of 690 alloy was studied in this paper. Firstly, M23C6 precipitation and evolution of chromium-depleted zone of 690 alloy during TT were studied. Evolution of chromium-depleted zone of 690 alloy was affected markedly by TT.The test results showed that the lowest chromium concentration in chromium-depleted zone raised dramatically after TT for 10 20h because of chromium backfill.The morphology of M23C6 in 690 alloy specimens changed obviously during different TT temperatures of 650 850°C. 690 alloy could get good M23C6 morphology though TT at 700 725°C and there appeared coarse M23C6 presenting multiple layer morphology when TT temperature reached 750 850°C. When treated for TT different time at 715°C, the M23C6 amount increased with extension of TT time and M23C6 could precipitate adequately while the TT time reached 15h.

Electrical properties of zinc-oxide-based thin-film transistors using strontium-oxide-doped semiconductors

NASA Astrophysics Data System (ADS)

Wu, Shao-Hang; Zhang, Nan; Hu, Yong-Sheng; Chen, Hong; Jiang, Da-Peng; Liu, Xing-Yuan

2015-10-01

Strontium-zinc-oxide (SrZnO) films forming the semiconductor layers of thin-film transistors (TFTs) are deposited by using ion-assisted electron beam evaporation. Using strontium-oxide-doped semiconductors, the off-state current can be dramatically reduced by three orders of magnitude. This dramatic improvement is attributed to the incorporation of strontium, which suppresses carrier generation, thereby improving the TFT. Additionally, the presence of strontium inhibits the formation of zinc oxide (ZnO) with the hexagonal wurtzite phase and permits the formation of an unusual phase of ZnO, thus significantly changing the surface morphology of ZnO and effectively reducing the trap density of the channel. Project supported by the National Natural Science Foundation of China (Grant No. 6140031454) and the Innovation Program of Chinese Academy of Sciences and State Key Laboratory of Luminescence and Applications.

Larval behavioral, morphological changes, and nematocyte dynamics during settlement of actinulae of Tubularia mesembryanthemum, Allman 1871 (Hydrozoa: Tubulariidae).

PubMed

Yamashita, Keiji; Kawaii, Satoru; Nakai, Mitsuyo; Fusetani, Nobuhiro

2003-06-01

The marine colonial hydroid Tubularia mesembryanthemum produces a morphologically unique dispersive stage, the actinula larva. Detailed observations were made on the behaviors and nematocyte dynamics of actinula larvae during attachment and morphogenesis by employing microscopic and time lapse video techniques. These observations produced four primary results. (1) Actinula larvae demonstrated two forms of attachment: temporary attachment by atrichous isorhiza (AI)-nematocysts discharged from the aboral tentacle (AT) tips-and permanent settlement by cement secretion from the columnar gland cells of the basal protrusion. (2) During larval settlement, numerous AIs were discharged from the AT tips with sinuous movement and rubbing of the tentacles onto the substrata, leading to "nematocyte-printing" around the settlement site. (3) Simultaneous with the discharge of the AIs, migration of stenoteles, desmonemes, and microbasic mastigophores occurred, resulting in a dramatic change of nematocyte composition in the ATs after larval settlement. This was in parallel with changes in larval behavior and the tentacle function. (4) Nematocyte-printing behavior during settlement could be recognized as metamorphic behavior responsible for irreversible changes in AT function, from attachment to feeding and defense.

Looking into the puparium: Micro-CT visualization of the internal morphological changes during metamorphosis of the blow fly, Calliphora vicina, with the first quantitative analysis of organ development in cyclorrhaphous dipterans.

PubMed

Martín-Vega, Daniel; Simonsen, Thomas J; Hall, Martin J R

2017-05-01

Metamorphosis of cyclorrhaphous flies takes place inside a barrel-like puparium, formed by the shrinking, hardening and darkening of the third-instar larval cuticle. The opacity of this structure hampers the visualization of the morphological changes occurring inside and therefore a full understanding of the metamorphosis process. Here, we use micro-computed tomography (micro-CT) to describe the internal morphological changes that occur during metamorphosis of the blow fly, Calliphora vicina Robineau-Desvoidy 1830 (Diptera: Calliphoridae) at a greater temporal resolution than anything hitherto published. The morphological changes were documented at 10% intervals of the total intra-puparial period, and down to 2.5% intervals during the first 20% interval, when the most dramatic morphological changes occur. Moreover, the development of an internal gas bubble, which plays an essential role during early metamorphosis, was further investigated with X-ray images and micro-CT virtual sections. The origin of this gas bubble has been largely unknown, but micro-CT virtual sections show that it is connected to one of the main tracheal trunks. Micro-CT virtual sections also provided enough resolution for determining the completion of the larval-pupal and pupal-adult apolyses, thus enabling an accurate timing of the different intra-puparial life stages. The prepupal, pupal, and pharate adult stages last for 7.5%, 22.5%, and 70% of the total intra-puparial development, respectively. Furthermore, we provide for the first time quantitative data on the development of two organ systems of the blow fly: the alimentary canal and the indirect flight muscles. There is a significant and negative correlation between the volume of the indirect flight muscles and the pre-helicoidal region of the midgut during metamorphosis. The latter occupies a large portion of the thorax during the pupal stage but narrows progressively as the indirect flight muscles increase in volume during the development of the pharate adult. © 2017 The Authors Journal of Morphology Published by Wiley Periodicals, Inc.

Identical Location Transmission Electron Microscopy Imaging of Site-Selective Pt Nanocatalysts: Electrochemical Activation and Surface Disordering.

PubMed

Arán-Ais, Rosa M; Yu, Yingchao; Hovden, Robert; Solla-Gullón, Jose; Herrero, Enrique; Feliu, Juan M; Abruña, Héctor D

2015-12-02

We have employed identical location transmission electron microscopy (IL-TEM) to study changes in the shape and morphology of faceted Pt nanoparticles as a result of electrochemical cycling; a procedure typically employed for activating platinum surfaces. We find that the shape and morphology of the as-prepared hexagonal nanoparticles are rapidly degraded as a result of potential cycling up to +1.3 V. As few as 25 potential cycles are sufficient to cause significant degradation, and after about 500-1000 cycles the particles are dramatically degraded. We also see clear evidence of particle migration during potential cycling. These finding suggest that great care must be exercised in the use and study of shaped Pt nanoparticles (and related systems) as electrocatlysts, especially for the oxygen reduction reaction where high positive potentials are typically employed.

Is there a morphological or physiological explanation for the dramatic increase in hybridization between loblolly and shortleaf pine?

Treesearch

Rodney E. Will; Curtis J. Lilly; John F. Stewart; C. Dana Nelson; Charles G. Taue

2015-01-01

Hybrids between shortleaf pine (Pinus echinata Mill.) and loblolly pine (P. taeda L.) have dramatically increased since the 1950s (Stewart and others 2012). Fire suppression, planting nonnative seed sources, and other anthropogenic activities have the potential to break down ecological barriers that previously kept these species from interbreeding (Tauer and others...

A morphology independent methodology for quantifying planview river change and characteristics from remotely sensed imagery

DOE PAGES

Rowland, Joel C.; Shelef, Eitan; Pope, Paul A.; ...

2016-07-15

Remotely sensed imagery of rivers has long served as a means for characterizing channel properties and detection of planview change. In the last decade the dramatic increase in the availability of satellite imagery and processing tools has created the potential to greatly expand the spatial and temporal scale of our understanding of river morphology and dynamics. To date, the majority of GIS and automated analyses of planview changes in rivers from remotely sensed data has been developed for single-threaded meandering river systems. These methods have limited applicability to many of the earth's rivers with complex multi-channel planforms. Here we presentmore » the methodologies of a set of analysis algorithms collectively called Spatially Continuous Riverbank Erosion and Accretion Measurements (SCREAM). SCREAM analyzes planview river metrics regardless of river morphology. These algorithms quantify both the erosion and accretion rates of riverbanks from binary masks of channels generated from imagery acquired at two time periods. Additionally, the program quantifies the area of change between river channels and the surrounding floodplain and area of islands lost or formed between these two time periods. To examine variations in erosion rates in relation to local channel attributes and make rate comparisons between river systems of varying sizes, the program determines channel widths and bank curvature at every bank pixel. SCREAM was developed and tested on rivers with diverse and complex planform morphologies in imagery acquired from a range of observational platforms with varying spatial resolutions. Here, validation and verification of SCREAM-generated metrics against manual measurements show no significant measurement errors in determination of channel width, erosion, and bank aspects. SCREAM has the potential to provide data for both the quantitative examination of the controls on erosion rates and for the comparison of these rates across river systems ranging broadly in size and planform morphology.« less

Complex and changing patterns of natural selection explain the evolution of the human hip.

PubMed

Grabowski, Mark; Roseman, Charles C

2015-08-01

Causal explanations for the dramatic changes that occurred during the evolution of the human hip focus largely on selection for bipedal function and locomotor efficiency. These hypotheses rest on two critical assumptions. The first-that these anatomical changes served functional roles in bipedalism-has been supported in numerous analyses showing how postcranial changes likely affected locomotion. The second-that morphological changes that did play functional roles in bipedalism were the result of selection for that behavior-has not been previously explored and represents a major gap in our understanding of hominin hip evolution. Here we use evolutionary quantitative genetic models to test the hypothesis that strong directional selection on many individual aspects of morphology was responsible for the large differences observed across a sample of fossil hominin hips spanning the Plio-Pleistocene. Our approach uses covariance among traits and the differences between relatively complete fossils to estimate the net selection pressures that drove the major transitions in hominin hip evolution. Our findings show a complex and changing pattern of natural selection drove hominin hip evolution, and that many, but not all, traits hypothesized to play functional roles in bipedalism evolved as a direct result of natural selection. While the rate of evolutionary change for all transitions explored here does not exceed the amount expected if evolution was occurring solely through neutral processes, it was far above rates of evolution for morphological traits in other mammalian groups. Given that stasis is the norm in the mammalian fossil record, our results suggest that large shifts in the adaptive landscape drove hominin evolution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Corn-like indium tin oxide nanostructures: fabrication, characterization and formation mechanism

NASA Astrophysics Data System (ADS)

Wu, Xu; Wang, Yihua; Yang, Bin

2015-11-01

Electrospinning is a simple but efficient procedure enabling the parallel fabrication of a multitude of inorganic fibers. But the precise control of the fiber's morphology, which seriously affects the electrical, optical and other important properties of such electrospun materials, is still less developed. The creation of nanoscale indium tin oxide fibers with corn-like geometry (corn-like ITO NFs) by our group has provided a good example to show how to modify the morphologies and properties of nanofibers by means of tailoring the fiber's compositions. Here we show that in the fabrication of corn-like ITO NFs, the usage of different solvents N, N-dimethylformamide (DMF) and deionized water, as well as the calcination temperature, can also lead to dramatic morphology changes, from ribbon-like to cylindrical and then to corn-like. The resultant nanoribbons and nanoscale corn-like fibers exhibit different photoluminescence properties. We find that the morphology of the as-spun fibers is closely related to the vapor pressure of the solvent we used, and the generation of ITO crystals sensitively depends on the calcination temperature, which both are critical for the morphology and properties of the final products. Thus, we demonstrate that the formation of this unprecedented nanostructure is determined by the combined effect of the precursor chemical composition, solvent and calcination temperature.

Biocompatibility of modified ultra-high-molecular-weight polyethylene

NASA Astrophysics Data System (ADS)

Novotná, Z.; Lacmanová, V.; Rimpelová, S.; Juřik, P.; Polívková, M.; Å vorčik, V.

2016-09-01

Ultra-high-molecular-weight polyethylene (UHMWPE, PE) is a synthetic polymer used for biomedical applications because of its high impact resistance, ductility and stability in contact with physiological fluids. Therefore this material is being used in human orthopedic implants such as total joint replacements. Surface modification of this material relates to changes of its surface hydrophilicity, energy, microstructure, roughness, and morphology, all influencing its biological response. In our recent work, PE was treated by an Ar+ plasma discharge and then grafted with biologically active polyethylene glycol in order to enhance adhesion and proliferation of mouse fibroblast (L929). The surface properties of pristine PE and its grafted counterparts were studied by goniometry (surface wettability). Furthermore, Atomic Force Microscopy was used to determine the surface morphology and roughness. The biological response of the L929 cell lines seeded on untreated and plasma treated PE matrices was quantified in terms of the cell adhesion, density, and metabolic activity. Plasma treatment leads to the ablation of the polymer surface layers. Plasma treatment and subsequent poly(ethylene glycol) grafting lead to dramatic changes in the polymer surface morphology and roughness. Biological tests, performed in vitro, show increased adhesion and proliferation of cells on modified polymers. Grafting with poly(ethylene glycol) increases cell proliferation compared to plasma treatment.

Constructing an Invasion Machine: The Rapid Evolution of a Dispersal-Enhancing Phenotype During the Cane Toad Invasion of Australia.

PubMed

Hudson, C M; McCurry, M R; Lundgren, P; McHenry, C R; Shine, R

Biological invasions can induce rapid evolutionary change. As cane toads (Rhinella marina) have spread across tropical Australia over an 80-year period, their rate of invasion has increased from around 15 to 60 km per annum. Toads at the invasion front disperse much faster and further than conspecifics from range-core areas, and their offspring inherit that rapid dispersal rate. We investigated morphological changes that have accompanied this dramatic acceleration, by conducting three-dimensional morphometric analyses of toads from both range-core and invasion-front populations. Morphology of heads, limbs, pectoral girdles and pelvic girdles differed significantly between toads from the two areas, ranging from 0.5% to 16.5% difference in mean bone dimensions between populations, with invasion-front toads exhibiting wider forelimbs, narrower hindlimbs and more compact skulls. Those changes plausibly reflect an increased reliance on bounding (multiple short hops in quick succession) rather than separate large leaps. Within an 80-year period, invasive cane toads have converted the basic anuran body plan - which evolved for occasional large leaps to evade predators - into a morphotype better-suited to sustained long-distance travel.

A Poorly Known High-Latitude Parasitoid Wasp Community: Unexpected Diversity and Dramatic Changes through Time

PubMed Central

Boudreault, Caroline; Goulet, Henri; Hebert, Paul D. N.; Smith, Adam C.

2011-01-01

Climate change will have profound and unanticipated effects on species distributions. The pace and nature of this change is largely unstudied, especially for the most diverse elements of terrestrial communities – the arthropods – here we have only limited knowledge concerning the taxonomy and the ecology of these groups. Because Arctic ecosystems have already experienced significant increases in temperature over the past half century, shifts in community structure may already be in progress. Here we utilise collections of a particularly hyperdiverse insect group – parasitoid wasps (Hymenoptera; Braconidae; Microgastrinae) – at Churchill, Manitoba, Canada in the early and mid-twentieth century to compare the composition of the contemporary community to that present 50–70 years ago. Morphological and DNA barcoding results revealed the presence of 79 species of microgastrine wasps in collections from Churchill, but we estimate that 20% of the local fauna awaits detection. Species composition and diversity between the two time periods differ significantly; species that were most common in historic collections were not found in contemporary collections and vice versa. Using barcodes we compared these collections to others from across North America; contemporary Churchill species are most affiliated with more south-western collections, while historic collections were more affiliated with eastern collections. The past five decades has clearly seen a dramatic change of species composition within the area studied coincident with rising temperature. PMID:21897854

Human Platelet Lysate versus Fetal Calf Serum: These Supplements Do Not Select for Different Mesenchymal Stromal Cells.

PubMed

Fernandez-Rebollo, Eduardo; Mentrup, Birgit; Ebert, Regina; Franzen, Julia; Abagnale, Giulio; Sieben, Torsten; Ostrowska, Alina; Hoffmann, Per; Roux, Pierre-François; Rath, Björn; Goodhardt, Michele; Lemaitre, Jean-Marc; Bischof, Oliver; Jakob, Franz; Wagner, Wolfgang

2017-07-11

Culture medium of mesenchymal stromal cells (MSCs) is usually supplemented with either human platelet lysate (HPL) or fetal calf serum (FCS). Many studies have demonstrated that proliferation and cellular morphology are affected by these supplements - it is therefore important to determine if they favor outgrowth of different subpopulations and thereby impact on the heterogeneous composition of MSCs. We have isolated and expanded human bone marrow-derived MSCs in parallel with HPL or FCS and demonstrated that HPL significantly increases proliferation and leads to dramatic differences in cellular morphology. Remarkably, global DNA-methylation profiles did not reveal any significant differences. Even at the transcriptomic level, there were only moderate changes in pairwise comparison. Furthermore, the effects on proliferation, cytoskeletal organization, and focal adhesions were reversible by interchanging to opposite culture conditions. These results indicate that cultivation of MSCs with HPL or FCS has no systematic bias for specific cell types.

A high resolution study of the glycocalyx of rat uterine epithelial cells during early pregnancy with the field emission gun scanning electron microscope.

PubMed Central

Jones, B J; Murphy, C R

1994-01-01

The field emission gun scanning electron microscope has been used to investigate morphological changes at the macromolecular level in the glycocalyx of rat uterine luminal epithelial cells during early pregnancy. This very high resolution microscope has allowed visualisation at a level previously unobtainable and has enabled us to establish that dramatic alterations occur in this glycocalyx at the time of blastocyst attachment. On d 1 of pregnancy a prominent, filamentous glycocalyx radiates from the microvilli. However, by d 6 of pregnancy when the microvilli have been replaced by irregular cell surface protrusions, the glycocalyceal filaments are completely lost and the plasma membrane appears smooth and covered with a felt-like coating. These morphological observations suggest a major reorganisation in surface carbohydrates during early pregnancy and extend histochemical observations on the uterine epithelial glycocalyx. Images Fig. 1 Fig. 2 Figs. 3 and 4 PMID:7961152

The formation of blobs from a pure interchange process

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

Zhu, P., E-mail: pzhu@ustc.edu.cn; Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706; Sovinec, C. R.

2015-02-15

In this work, we focus on examining a pure interchange process in a shear-less slab configuration as a prototype mechanism for blob formation. We employ full magnetohydrodynamic simulations to demonstrate that the blob-like structures can emerge through the nonlinear development of a pure interchange instability originating from a pedestal-like transition region. In the early nonlinear stage, filamentary structures develop and extend in the direction of the effective gravity. The blob-like structures appear when the radially extending filaments break off and disconnect from the core plasma. The morphology and the dynamics of these filaments and blobs vary dramatically with a sensitivemore » dependence on the dissipation mechanisms in the system and the initial perturbation. Despite the complexity in morphology and dynamics, the nature of the entire blob formation process in the shear-less slab configuration remains strictly interchange without involving any change in magnetic topology.« less

Dynamics and Morphology of Saturn’s North Polar Region During Cassini’s Final Year

NASA Astrophysics Data System (ADS)

Blalock, John J.; Sayanagi, Kunio M.; Ingersoll, Andrew P.; Dyudina, Ulyana A.; Ewald, Shawn; McCabe, Ryan M.; Gunnarson, Jacob; Garland, Justin; Gallego, Angelina

2017-10-01

We present an analysis of Saturn’s north polar region utilizing Cassini ISS images captured in visible and near-infrared wavelengths during late 2016 and 2017, including images captured during Cassini’s Grand Finale orbits. To measure the wind field in the region, we utilize the two-dimensional correlation imaging velocimetry (CIV) technique. We also calculate the relative vorticity and divergence from the wind field. To detect changes in the dynamics, we compare measurements of the wind, relative vorticity, and divergence in 2012 and 2013 with those from 2016/2017. We also compare cloud reflectivity between 2012/2013 and 2016/2017 in images that show the north pole under similar illumination conditions. To detect changes in cloud reflectivity, we utilize a Minnaert correction to calculate the zonal mean reflectivity as a function of latitude. Furthermore, we compare the winds and cloud reflectivity at several wavelengths in order to look for changes occurring at different altitudes. Our results indicate that while the dynamics of the north polar region have remained relatively stable, there have been significant morphology changes that have resulted in dramatic color changes. We hypothesize that these changes are a result of the seasonal cycle and linked to the increased production of photochemical hazes in the atmosphere. Our work has been supported by NASA PATM NNX14AK07G, NSF AAG 1212216, and NASA NESSF NNX15AQ70H.

Modeling electronic trap state distributions in nanocrystalline anatase

NASA Astrophysics Data System (ADS)

Le, Nam; Schweigert, Igor

The charge transport properties of nanocrystalline TiO2 films, and thus the catalytic performance of devices that incorporate them, are affected strongly by the spatial and energetic distribution of localized electronic trap states. Such traps may arise from a variety of defects: Ti interstitials, O vacancies, step edges at surfaces, and grain boundaries. We have developed a procedure for applying density functional theory (DFT) and density functional tight binding (DFTB) calculations to characterize distributions of localized states arising from multiple types of defects. We have applied the procedure to investigate how the morphologies of interfaces between pairs of attached anatase nanoparticles determine the energies of trap states therein. Our results complement recent experimental findings that subtle changes in the morphology of highly porous TiO2 aerogel networks can have a dramatic effect on catalytic performance, which was attributed to changes in the distribution of trap states. This work was supported by the U.S. Naval Research Laboratory via the National Research Council and by the Office of Naval Research through the U.S. Naval Research Laboratory.

Multiphase materials with lignin: 5. Effect of lignin atructure on hydroxypropyl cellulose blend morphology

Treesearch

Timothy G. Rials; Wolfgang G. Glasser

1990-01-01

The incremental elimination of hydroxy functionality in an organosolv lignin by ethylation or acetylation dramatically influenced the state of miscibility and resulting morphology of blends prepared with hydroxypropyl cellulose (HPC). A maximum level of interation between the blend components, as determined from melting point depression, occurred where 23-40% of the...

Sensory system plasticity in a visually specialized, nocturnal spider.

PubMed

Stafstrom, Jay A; Michalik, Peter; Hebets, Eileen A

2017-04-21

The interplay between an animal's environmental niche and its behavior can influence the evolutionary form and function of its sensory systems. While intraspecific variation in sensory systems has been documented across distant taxa, fewer studies have investigated how changes in behavior might relate to plasticity in sensory systems across developmental time. To investigate the relationships among behavior, peripheral sensory structures, and central processing regions in the brain, we take advantage of a dramatic within-species shift of behavior in a nocturnal, net-casting spider (Deinopis spinosa), where males cease visually-mediated foraging upon maturation. We compared eye diameters and brain region volumes across sex and life stage, the latter through micro-computed X-ray tomography. We show that mature males possess altered peripheral visual morphology when compared to their juvenile counterparts, as well as juvenile and mature females. Matching peripheral sensory structure modifications, we uncovered differences in relative investment in both lower-order and higher-order processing regions in the brain responsible for visual processing. Our study provides evidence for sensory system plasticity when individuals dramatically change behavior across life stages, uncovering new avenues of inquiry focusing on altered reliance of specific sensory information when entering a new behavioral niche.

Solid dispersion of acetaminophen and poly(ethylene oxide) prepared by hot-melt mixing.

PubMed

Yang, Min; Wang, Peng; Huang, Chien-Yueh; Ku, M Sherry; Liu, Huiju; Gogos, Costas

2010-08-16

In this study, a model drug, acetaminophen (APAP), was melt mixed with poly(ethylene oxide) (PEO) using a Brabender mixer. APAP was found to recrystallize upon cooling to room temperature for all the drug loadings investigated. Higher drug loading leads to faster recrystallization rate. However, the morphology of the recrystallized drug crystals is identical in samples with different drug loadings and does not change with the storage time. To adjust the drug's dissolution rate, nanoclay Cloisite 15A and 30B were added into the binary mixture. The presence of either of the nanoclay dramatically accelerates the drug's recrystallization rate and slows down the drug's releasing rate. The drop of the releasing rate is mainly due to the decrease of wettability, as supported by the contact angle data. Data analysis of the dissolution results suggests that the addition of nanoclays changes the drug's release mechanism from erosion dominant to diffusion dominant. This study suggests that nanoclays may be utilized to tailor the drug's releasing rate and to improve the dosage form's stability by dramatically shortening the lengthy recrystallization process. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Antiquity of the South Atlantic Anomaly and evidence for top-down control on the geodynamo.

PubMed

Tarduno, John A; Watkeys, Michael K; Huffman, Thomas N; Cottrell, Rory D; Blackman, Eric G; Wendt, Anna; Scribner, Cecilia A; Wagner, Courtney L

2015-07-28

The dramatic decay of dipole geomagnetic field intensity during the last 160 years coincides with changes in Southern Hemisphere (SH) field morphology and has motivated speculation of an impending reversal. Understanding these changes, however, has been limited by the lack of longer-term SH observations. Here we report the first archaeomagnetic curve from southern Africa (ca. 1000-1600 AD). Directions change relatively rapidly at ca. 1300 AD, whereas intensities drop sharply, at a rate greater than modern field changes in southern Africa, and to lower values. We propose that the recurrence of low field strengths reflects core flux expulsion promoted by the unusual core-mantle boundary (CMB) composition and structure beneath southern Africa defined by the African large low shear velocity province (LLSVP). Because the African LLSVP and CMB structure are ancient, this region may have been a steady site for flux expulsion, and triggering of geomagnetic reversals, for millions of years.

Looking into the puparium: Micro‐CT visualization of the internal morphological changes during metamorphosis of the blow fly, Calliphora vicina, with the first quantitative analysis of organ development in cyclorrhaphous dipterans

PubMed Central

Simonsen, Thomas J.; Hall, Martin J. R.

2017-01-01

Abstract Metamorphosis of cyclorrhaphous flies takes place inside a barrel‐like puparium, formed by the shrinking, hardening and darkening of the third‐instar larval cuticle. The opacity of this structure hampers the visualization of the morphological changes occurring inside and therefore a full understanding of the metamorphosis process. Here, we use micro‐computed tomography (micro‐CT) to describe the internal morphological changes that occur during metamorphosis of the blow fly, Calliphora vicina Robineau‐Desvoidy 1830 (Diptera: Calliphoridae) at a greater temporal resolution than anything hitherto published. The morphological changes were documented at 10% intervals of the total intra‐puparial period, and down to 2.5% intervals during the first 20% interval, when the most dramatic morphological changes occur. Moreover, the development of an internal gas bubble, which plays an essential role during early metamorphosis, was further investigated with X‐ray images and micro‐CT virtual sections. The origin of this gas bubble has been largely unknown, but micro‐CT virtual sections show that it is connected to one of the main tracheal trunks. Micro‐CT virtual sections also provided enough resolution for determining the completion of the larval‐pupal and pupal‐adult apolyses, thus enabling an accurate timing of the different intra‐puparial life stages. The prepupal, pupal, and pharate adult stages last for 7.5%, 22.5%, and 70% of the total intra‐puparial development, respectively. Furthermore, we provide for the first time quantitative data on the development of two organ systems of the blow fly: the alimentary canal and the indirect flight muscles. There is a significant and negative correlation between the volume of the indirect flight muscles and the pre‐helicoidal region of the midgut during metamorphosis. The latter occupies a large portion of the thorax during the pupal stage but narrows progressively as the indirect flight muscles increase in volume during the development of the pharate adult. PMID:28182298

Spatially Directed Proteomics of the Human Lens Outer Cortex Reveals an Intermediate Filament Switch Associated With the Remodeling Zone

PubMed Central

Wenke, Jamie L.; McDonald, W. Hayes; Schey, Kevin L.

2016-01-01

Purpose To quantify protein changes in the morphologically distinct remodeling zone (RZ) and adjacent regions of the human lens outer cortex using spatially directed quantitative proteomics. Methods Lightly fixed human lens sections were deparaffinized and membranes labeled with fluorescent wheat germ agglutinin (WGA-TRITC). Morphology directed laser capture microdissection (LCM) was used to isolate tissue from four distinct regions of human lens outer cortex: differentiating zone (DF), RZ, transition zone (TZ), and inner cortex (IC). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) of the plasma membrane fraction from three lenses (21-, 22-, and 27-year) revealed changes in major cytoskeletal proteins including vimentin, filensin, and phakinin. Peptides from proteins of interest were quantified using multiple reaction monitoring (MRM) mass spectrometry and isotopically-labeled internal peptide standards. Results Results revealed an intermediate filament switch from vimentin to beaded filament proteins filensin and phakinin that occurred at the RZ. Several other cytoskeletal proteins showed significant changes between regions, while most crystallins remained unchanged. Targeted proteomics provided accurate, absolute quantification of these proteins and confirmed vimentin, periplakin, and periaxin decrease from the DF to the IC, while filensin, phakinin, and brain acid soluble protein 1 (BASP1) increase significantly at the RZ. Conclusions Mass spectrometry-compatible fixation and morphology directed laser capture enabled proteomic analysis of narrow regions in the human lens outer cortex. Results reveal dramatic cytoskeletal protein changes associated with the RZ, suggesting that one role of these proteins is in membrane deformation and/or the establishment of ball and socket joints in the human RZ. PMID:27537260

Application of myostatin in sheep breeding programs: A review

PubMed Central

Miar, Younes; Salehi, Abdolreza; Kolbehdari, Davood; Aleyasin, Seyed Ahmad

2014-01-01

Plasma membrane H+-ATPase is a major integral membrane protein with a role in various physiological processes including abiotic stress response. To study the effect of NaCl on the expression pattern of a gene encoding the plasma membrane H+-ATPase, an experiment was carried out in a completely random design with three replications. A pair of specific primers was designed based on the sequence of the gene encoding plasma membrane H+-ATPase in Aeluropus littoralis to amplify a 259 bp fragment from the target gene by PCR. A gene encoding actin was used as reference gene to normalize the expression level of the target gene. A pair of specific primers was designed to amplify a 157 bp fragment from the actin gene by PCR. Plants were treated with different concentrations of NaCl, 0, 50, 100, 150, 200, 250, 500 and 1000 mM, for two days. Our results showed that the expression level of the plasma membrane H+-ATPase gene increased dramatically at 500 mM and then decreased with increasing concentrations of NaCl. The results also indicated that the leaves of plants, were treated with high concentrations of NaCl changed morphologically, but those grown under low concentrations of NaCl as well as the control plants did not show morphological changes in their leaves. Our results suggest a relation between morphological changes of treated plants and the expression level of the plasma membrane H+-ATPase gene in Aeluropus littoralis. PMID:27843975

Modifications in plasma membrane lipid composition and morphological features of AH-130 hepatoma cells by polyenylphosphatidylcholine in vivo treatment.

PubMed

Cinosi, Vincenzo; Antonini, Roberto; Crateri, Pasqualina; Arancia, Giuseppe

2011-07-01

The plasma membrane lipid composition in AH-130 hepatoma cells was found to change remarkably after polyenylphosphatidylcholine (PPC) treatment. Plasma membranes from cells grown in rats treated for 7 days i.v. with 20 mg/kg/day PPC, when compared to those of control cells, did not show significantly different amounts of cholesterol or phospholipids relative to protein content, but, surprisingly, the individual phospholipid distribution inside the two membrane leaflets changed dramatically. Phosphatidylcholine (PC), the major phospholipid in the external membrane leaflet, increased ~47% (p<0.001). By contrast, phosphatidylethanolamine (PE), the most important component of the inner leaflet, decreased nearly 37% (p<0.001), while sphingomyelin (SM) also decreased ~17%, (p=0.1). Tumor cells collected from control rats at the same time interval and observed by scanning electron microscopy, exhibited a spherical shape with numerous and randomly distributed long microvilli, the same morphological and ultrastructural features displayed by the implanted cells. Conversely, tumor cells from PPC-treated rats no longer showed the roundish cell profile, and microvilli appeared shortened and enlarged, with the formation of surface blebs. Transmission electron microscopy observations confirmed the morphological and ultrastructural cell changes, mainly seen as loss of microvilli and intense cytoplasmic vacuolization. Taken together, these results indicate that the new phospholipid class distribution in the plasma membrane leaflets, modifying tumor cell viable structures, produced heavy cell damage and in many cases brought about complete cellular disintegration.

Forelimb kinematics and motor patterns of swimming loggerhead sea turtles (Caretta caretta): are motor patterns conserved in the evolution of new locomotor strategies?

PubMed

Rivera, Angela R V; Wyneken, Jeanette; Blob, Richard W

2011-10-01

Novel functions in animals may evolve through changes in morphology, muscle activity or a combination of both. The idea that new functions or behavior can arise solely through changes in structure, without concurrent changes in the patterns of muscle activity that control movement of those structures, has been formalized as the neuromotor conservation hypothesis. In vertebrate locomotor systems, evidence for neuromotor conservation is found across evolutionary transitions in the behavior of terrestrial species, and in evolutionary transitions from terrestrial species to flying species. However, evolutionary transitions in the locomotion of aquatic species have received little comparable study to determine whether changes in morphology and muscle function were coordinated through the evolution of new locomotor behavior. To evaluate the potential for neuromotor conservation in an ancient aquatic system, we quantified forelimb kinematics and muscle activity during swimming in the loggerhead sea turtle, Caretta caretta. Loggerhead forelimbs are hypertrophied into wing-like flippers that produce thrust via dorsoventral forelimb flapping. We compared kinematic and motor patterns from loggerheads with previous data from the red-eared slider, Trachemys scripta, a generalized freshwater species exhibiting unspecialized forelimb morphology and anteroposterior rowing motions during swimming. For some forelimb muscles, comparisons between C. caretta and T. scripta support neuromotor conservation; for example, the coracobrachialis and the latissimus dorsi show similar activation patterns. However, other muscles (deltoideus, pectoralis and triceps) do not show neuromotor conservation; for example, the deltoideus changes dramatically from a limb protractor/elevator in sliders to a joint stabilizer in loggerheads. Thus, during the evolution of flapping in sea turtles, drastic restructuring of the forelimb was accompanied by both conservation and evolutionary novelty in limb motor patterns.

Evolution of mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane: Implications for barrier-estuary connectivity

USGS Publications Warehouse

Miselis, Jennifer L.; Andrews, Brian D.; Nicholson, Robert S.; Defne, Zafer; Ganju, Neil K.; Navoy, Anthony S.

2016-01-01

Assessments of coupled barrier island-estuary storm response are rare. Hurricane Sandy made landfall during an investigation in Barnegat Bay-Little Egg Harbor estuary that included water quality monitoring, geomorphologic characterization, and numerical modeling; this provided an opportunity to characterize the storm response of the barrier island-estuary system. Barrier island morphologic response was characterized by significant changes in shoreline position, dune elevation, and beach volume; morphologic changes within the estuary were less dramatic with a net gain of only 200,000 m3 of sediment. When observed, estuarine deposition was adjacent to the back-barrier shoreline or collocated with maximum estuary depths. Estuarine sedimentologic changes correlated well with bed shear stresses derived from numerically simulated storm conditions, suggesting that change is linked to winnowing from elevated storm-related wave-current interactions rather than deposition. Rapid storm-related changes in estuarine water level, turbidity, and salinity were coincident with minima in island and estuarine widths, which may have influenced the location of two barrier island breaches. Barrier-estuary connectivity, or the transport of sediment from barrier island to estuary, was influenced by barrier island land use and width. Coupled assessments like this one provide critical information about storm-related coastal and estuarine sediment transport that may not be evident from investigations that consider only one component of the coastal system.

Evolution of Sex-Specific Traits through Changes in HOX-Dependent doublesex Expression

PubMed Central

Tanaka, Kohtaro; Barmina, Olga; Sanders, Laura E.; Arbeitman, Michelle N.; Kopp, Artyom

2011-01-01

Almost every animal lineage is characterized by unique sex-specific traits, implying that such traits are gained and lost frequently in evolution. However, the genetic mechanisms responsible for these changes are not understood. In Drosophila, the activity of the sex determination pathway is restricted to sexually dimorphic tissues, suggesting that spatial regulation of this pathway may contribute to the evolution of sex-specific traits. We examine the regulation and function of doublesex (dsx), the main transcriptional effector of the sex determination pathway, in the development and evolution of Drosophila sex combs. Sex combs are a recent evolutionary innovation and show dramatic diversity in the relatively few Drosophila species that have them. We show that dsx expression in the presumptive sex comb region is activated by the HOX gene Sex combs reduced (Scr), and that the male isoform of dsx up-regulates Scr so that both genes become expressed at high levels in this region in males but not in females. Precise spatial regulation of dsx is essential for defining sex comb position and morphology. Comparative analysis of Scr and dsx expression reveals a tight correlation between sex comb morphology and the expression patterns of both genes. In species that primitively lack sex combs, no dsx expression is observed in the homologous region, suggesting that the origin and diversification of this structure were linked to the gain of a new dsx expression domain. Two other, distantly related fly lineages that independently evolved novel male-specific structures show evolutionary gains of dsx expression in the corresponding tissues, where dsx may also be controlled by Scr. These findings suggest that changes in the spatial regulation of sex-determining genes are a key mechanism that enables the evolution of new sex-specific traits, contributing to some of the most dramatic examples of phenotypic diversification in nature. PMID:21886483

Influence of multi-wavelength laser irradiation of enamel and dentin surfaces at 0.355, 2.94, and 9.4 μm on surface morphology, permeability, and acid resistance.

PubMed

Chang, Nai-Yuan N; Jew, Jamison M; Simon, Jacob C; Chen, Kenneth H; Lee, Robert C; Fried, William A; Cho, Jinny; Darling, Cynthia L; Fried, Daniel

2017-12-01

Ultraviolet (UV) and infrared (IR) lasers can be used to specifically target protein, water, and mineral, respectively, in dental hard tissues to produce varying changes in surface morphology, permeability, reflectivity, and acid resistance. The purpose of this study was to explore the influence of laser irradiation and topical fluoride application on the surface morphology, permeability, reflectivity, and acid resistance of enamel and dentin to shed light on the mechanism of interaction and develop more effective treatments. Twelve bovine enamel surfaces and twelve bovine dentin surfaces were irradiated with various combinations of lasers operating at 0.355 (Freq.-tripled Nd:YAG (UV) laser), 2.94 (Er:YAG laser), and 9.4 μm (CO 2 laser), and surfaces were exposed to an acidulated phosphate fluoride gel and an acid challenge. Changes in the surface morphology, acid resistance, and permeability were measured using digital microscopy, polarized light microscopy, near-IR reflectance, fluorescence, polarization sensitive-optical coherence tomography (PS-OCT), and surface dehydration rate measurements. Different laser treatments dramatically influenced the surface morphology and permeability of both enamel and dentin. CO 2 laser irradiation melted tooth surfaces. Er:YAG and UV lasers, while not melting tooth surfaces, showed markedly different surface roughness. Er:YAG irradiation led to significantly rougher enamel and dentin surfaces and led to higher permeability. There were significant differences in acid resistance among the various treatment groups. Surface dehydration measurements showed significant changes in permeability after laser treatments, application of fluoride and after exposure to demineralization. CO 2 laser irradiation was most effective in inhibiting demineralization on enamel while topical fluoride was most effective for dentin surfaces. Lasers Surg. Med. 49:913-927, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Nanoscale size effects on the mechanical properties of platinum thin films and cross-sectional grain morphology

NASA Astrophysics Data System (ADS)

Abbas, K.; Alaie, S.; Ghasemi Baboly, M.; Elahi, M. M. M.; Anjum, D. H.; Chaieb, S.; Leseman, Z. C.

2016-01-01

The mechanical behavior of polycrystalline Pt thin films is reported for thicknesses of 75 nm, 100 nm, 250 nm, and 400 nm. These thicknesses correspond to transitions between nanocrystalline grain morphology types as found in TEM studies. Thinner samples display a brittle behavior, but as thickness increases the grain morphology evolves, leading to a ductile behavior. During evolution of the morphology, dramatic differences in elastic moduli (105-160 GPa) and strengths (560-1700 MPa) are recorded and explained by the variable morphology. This work suggests that in addition to the in-plane grain size of thin films, the transitions in cross-sectional morphologies of the Pt films significantly affect their mechanical behavior.

Effect of the theta-alpha-Al2O3 transformation on the oxidation behavior of beta-NiAl+Zr

NASA Technical Reports Server (NTRS)

Rybicki, George C.; Smialek, James L.

1989-01-01

Isothermal oxidation of NiAl+Zr has been performed over the temperature range of 800-1200 C and studied by TGA, XRD, and SEM. A discontinuous decrease in growth rate of two orders of magnitude was observed at 1000 C due to the formation of alpha-Al2O3 from theta-Al2O3. This transformation also resulted in a dramatic change in the surface morphology of the scales, as a whisker topography was changed into a weblike network of oxide ridges and radial transformation cracks. It is believed that the ridges are evidence for a short-circuit outward aluminum diffusion growth mechanism that has been documented in a number of O-18 tracer studies.

Repression of gibberellin biosynthesis or signaling produces striking alterations in poplar growth, morphology, and flowering.

PubMed

Zawaski, Christine; Kadmiel, Mahita; Pickens, Jim; Ma, Cathleen; Strauss, Steven; Busov, Victor

2011-12-01

We modified gibberellin (GA) metabolism and signaling in transgenic poplars using dominant transgenes and studied their effects for 3 years under field conditions. The transgenes that we employed either reduced the bioactive GAs, or attenuated their signaling. The majority of transgenic trees had significant and in many cases dramatic changes in height, crown architecture, foliage morphology, flowering onset, floral structure, and vegetative phenology. Most transgenes elicited various levels of height reduction consistent with the roles of GA in elongation growth. Several other growth traits were proportionally reduced, including branch length, internode distance, and leaf length. In contrast to elongation growth, stem diameter growth was much less affected, suggesting that semi-dwarf trees in dense stands might provide high levels of biomass production and carbon sequestration. The severity of phenotypic effects was strongly correlated with transgene expression among independent transgenic events, but often in a non-linear manner, the form of which varied widely among constructs. The majority of semi-dwarfed, transgenic plants showed delayed bud flush and early bud set, and expression of a native GAI transgene accelerated first time flowering in the field. All of the phenotypic changes observed in multiple years were stable over the 3 years of field study. Our results suggest that transgenic modification of GA action may be useful for producing semi-dwarf trees with modified growth and morphology for horticulture and other uses.

Characterization of morphological response of red cells in a sucrose solution.

PubMed

Rudenko, Sergey V

2009-01-01

The dynamics of red cell shape changes following transfer into sucrose media having a low chloride content was studied. Based on a large number of measurements, six types of morphological response (MR), differing both in the degree of shape changes and the time course of the process, were identified. The most prominent type of response is a triphasic sequence of shape changes consisting of a fast transformation into a sphere (phase 1), followed by restoration of the discoid shape (phase 2) and final transformation into spherostomatocytes (phase 3), with individual parameters which could vary significantly. It was found that individual morphological response exhibited day to day variations, depending on the initial state of the red blood cells and the donor, but to a larger extent depended on the composition of the sucrose solution, such as concentration and type of buffers, the presence of EDTA, calcium, as well as very small amounts of extracellular hemoglobin. MR shows strong pH and ionic strength dependence. Low pH inhibited phase 1 and high pH changed dramatically the time course of the response. Increasing ionic strength inhibited all phases of MR, and at concentrations above 10-20 mM NaCl it was fully suppressed. Tris and phosphate were also inhibitory whereas HEPES, MOPS and Tricine were less effective. MR occurred also in hypertonic or hypotonic sucrose solutions, with exception of extreme hypotonicity due to volume restrictions. It is concluded that strong membrane depolarization per se is not a causal factor leading to MR, and its different phases could be regulated independently. For some types of morphological response the fast shape transformation from sphere to disc and back to sphere occurs within a 10 s time interval and could be accelerated several fold in the presence of a small amount of hemoglobin. It is suggested that MR represents a type of general cell reaction that occurs upon exposure to low ionic strength.

Morphological and quantitative changes in mitochondria, plastids, and peroxisomes during the log-to-stationary transition of the growth phase in cultured tobacco BY-2 cells.

PubMed

Toyooka, Kiminori; Sato, Mayuko; Wakazaki, Mayumi; Matsuoka, Ken

2016-01-01

We developed a wide-range and high-resolution transmission electron microscope acquisition system and obtained giga-pixel images of tobacco BY-2 cells during the log and stationary phases of cell growth. We demonstrated that the distribution and ultrastructure of compartments involved in membrane traffic (i.e., Golgi apparatus, multivesicular body, and vesicle cluster) change during the log-to-stationary transition. Mitochondria, peroxisomes, and plastids were also enumerated. Electron densities of mitochondria and peroxisomes were altered during the growth-phase shift, while their numbers were reduced by nearly half. Plastid structure dramatically changed from atypical to spherical with starch granules. Nearly the same number of plastids was observed in both log and stationary phases. These results indicate that mechanisms regulating organelle populations differ from organelle to organelle.

A unique coral biomineralization pattern has resisted 40 million years of major ocean chemistry change

NASA Astrophysics Data System (ADS)

Stolarski, Jarosław; Bosellini, Francesca R.; Wallace, Carden C.; Gothmann, Anne M.; Mazur, Maciej; Domart-Coulon, Isabelle; Gutner-Hoch, Eldad; Neuser, Rolf D.; Levy, Oren; Shemesh, Aldo; Meibom, Anders

2016-06-01

Today coral reefs are threatened by changes to seawater conditions associated with rapid anthropogenic global climate change. Yet, since the Cenozoic, these organisms have experienced major fluctuations in atmospheric CO2 levels (from greenhouse conditions of high pCO2 in the Eocene to low pCO2 ice-house conditions in the Oligocene-Miocene) and a dramatically changing ocean Mg/Ca ratio. Here we show that the most diverse, widespread, and abundant reef-building coral genus Acropora (20 morphological groups and 150 living species) has not only survived these environmental changes, but has maintained its distinct skeletal biomineralization pattern for at least 40 My: Well-preserved fossil Acropora skeletons from the Eocene, Oligocene, and Miocene show ultra-structures indistinguishable from those of extant representatives of the genus and their aragonitic skeleton Mg/Ca ratios trace the inferred ocean Mg/Ca ratio precisely since the Eocene. Therefore, among marine biogenic carbonate fossils, well-preserved acroporid skeletons represent material with very high potential for reconstruction of ancient ocean chemistry.

A normal genetic variation modulates synaptic MMP-9 protein levels and the severity of schizophrenia symptoms.

PubMed

Lepeta, Katarzyna; Purzycka, Katarzyna J; Pachulska-Wieczorek, Katarzyna; Mitjans, Marina; Begemann, Martin; Vafadari, Behnam; Bijata, Krystian; Adamiak, Ryszard W; Ehrenreich, Hannelore; Dziembowska, Magdalena; Kaczmarek, Leszek

2017-08-01

Matrix metalloproteinase 9 (MMP-9) has recently emerged as a molecule that contributes to pathological synaptic plasticity in schizophrenia, but explanation of the underlying mechanisms has been missing. In the present study, we performed a phenotype-based genetic association study (PGAS) in > 1,000 schizophrenia patients from the Göttingen Research Association for Schizophrenia (GRAS) data collection and found an association between the MMP-9 rs20544 C/T single-nucleotide polymorphism (SNP) located in the 3'untranslated region (UTR) and the severity of a chronic delusional syndrome. In cultured neurons, the rs20544 SNP influenced synaptic MMP-9 activity and the morphology of dendritic spines. We demonstrated that Fragile X mental retardation protein (FMRP) bound the MMP-9 3'UTR We also found dramatic changes in RNA structure folding and alterations in the affinity of FMRP for MMP-9 RNA, depending on the SNP variant. Finally, we observed greater sensitivity to psychosis-related locomotor hyperactivity in Mmp-9 heterozygous mice. We propose a novel mechanism that involves MMP-9-dependent changes in dendritic spine morphology and the pathophysiology of schizophrenia, providing the first mechanistic insights into the way in which the single base change in the MMP-9 gene (rs20544) influences gene function and results in phenotypic changes observed in schizophrenia patients. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

Wide-range high-resolution transmission electron microscopy reveals morphological and distributional changes of endomembrane compartments during log to stationary transition of growth phase in tobacco BY-2 cells.

PubMed

Toyooka, Kiminori; Sato, Mayuko; Kutsuna, Natsumaro; Higaki, Takumi; Sawaki, Fumie; Wakazaki, Mayumi; Goto, Yumi; Hasezawa, Seiichiro; Nagata, Noriko; Matsuoka, Ken

2014-09-01

Rapid growth of plant cells by cell division and expansion requires an endomembrane trafficking system. The endomembrane compartments, such as the Golgi stacks, endosome and vesicles, are important in the synthesis and trafficking of cell wall materials during cell elongation. However, changes in the morphology, distribution and number of these compartments during the different stages of cell proliferation and differentiation have not yet been clarified. In this study, we examined these changes at the ultrastructural level in tobacco Bright yellow 2 (BY-2) cells during the log and stationary phases of growth. We analyzed images of the BY-2 cells prepared by the high-pressure freezing/freeze substitution technique with the aid of an auto-acquisition transmission electron microscope system. We quantified the distribution of secretory and endosomal compartments in longitudinal sections of whole cells by using wide-range gigapixel-class images obtained by merging thousands of transmission electron micrographs. During the log phase, all Golgi stacks were composed of several thick cisternae. Approximately 20 vesicle clusters (VCs), including the trans-Golgi network and secretory vesicle cluster, were observed throughout the cell. In the stationary-phase cells, Golgi stacks were thin with small cisternae, and only a few VCs were observed. Nearly the same number of multivesicular body and small high-density vesicles were observed in both the stationary and log phases. Results from electron microscopy and live fluorescence imaging indicate that the morphology and distribution of secretory-related compartments dramatically change when cells transition from log to stationary phases of growth. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Spatially variant morphological restoration and skeleton representation.

PubMed

Bouaynaya, Nidhal; Charif-Chefchaouni, Mohammed; Schonfeld, Dan

2006-11-01

The theory of spatially variant (SV) mathematical morphology is used to extend and analyze two important image processing applications: morphological image restoration and skeleton representation of binary images. For morphological image restoration, we propose the SV alternating sequential filters and SV median filters. We establish the relation of SV median filters to the basic SV morphological operators (i.e., SV erosions and SV dilations). For skeleton representation, we present a general framework for the SV morphological skeleton representation of binary images. We study the properties of the SV morphological skeleton representation and derive conditions for its invertibility. We also develop an algorithm for the implementation of the SV morphological skeleton representation of binary images. The latter algorithm is based on the optimal construction of the SV structuring element mapping designed to minimize the cardinality of the SV morphological skeleton representation. Experimental results show the dramatic improvement in the performance of the SV morphological restoration and SV morphological skeleton representation algorithms in comparison to their translation-invariant counterparts.

Predation as the primary selective force in recurrent evolution of gigantism in Poecilozonites land snails in Quaternary Bermuda.

PubMed

Olson, Storrs L; Hearty, Paul J

2010-12-23

During the last half million years, pulses of gigantism in the anagenetic lineage of land snails of the subgenus Poecilozonites on Bermuda were correlated with glacial periods when lower sea level resulted in an island nearly an order of magnitude larger than at present. During those periods, the island was colonized by large vertebrate predators that created selection pressure for large size and rapid growth in the snails. Extreme reduction in land area from rising seas, along with changes in ecological conditions at the onset of interglacial episodes, marked extinction events for large predators, after which snails reverted to much smaller size. The giant snails were identical in morphology during the last two glacials when the predators included a large flightless rail Rallus recessus (marine isotope stages (MIS) 4-2) and a crane Grus latipes and a duck Anas pachysceles (MIS 6). In a preceding glacial period (MIS 10), when the fauna also included the tortoise Hesperotestudo bermudae, the snails were not only large, but the shells were much thicker, presumably to prevent crushing by tortoises. Evolution of Poecilozonites provides an outstanding example of dramatic morphological change in response to environmental pressures in the absence of cladogenesis.

High-temperature investigation on morphology, phase and size of iron/iron-oxide core–shell nanoclusters for radiation nanodetector

NASA Astrophysics Data System (ADS)

Khanal, Lokendra Raj; Williams, Thomas; Qiang, You

2018-06-01

Iron/iron-oxide (Fe–Fe3O4) core–shell nanoclusters (NCs) synthesized by a cluster deposition technique were subjected to a study of their high temperature structural and morphological behavior. Annealing effects have been investigated up to 800 °C in vacuum, oxygen and argon environments. The ~18 nm average size of the as-prepared NCs increases slowly in temperatures up to 500 °C in all three environments. The size increases abruptly in the argon environment but slowly in vacuum and oxygen when annealed at 800 °C. The x-ray diffraction (XRD) studies have shown that the iron core remains in the core–shell NCs only when they were annealed in the vacuum. A dramatic change in the surface morphology, an island like structure and/or a network like pattern, was observed at the elevated temperature. The as-prepared and annealed samples were analyzed using XRD, scanning electron microscopy and imageJ software for a close inspection of the temperature aroused properties. This work presents the temperature induced size growth mechanism, oxidation kinetics and phase transformation of the NCs accompanied by cluster aggregation, particle coalescence, and diffusion.

KSHV-TK is a tyrosine kinase that disrupts focal adhesions and induces Rho-mediated cell contraction

PubMed Central

Gill, Michael B; Turner, Rachel; Stevenson, Philip G; Way, Michael

2015-01-01

Paradoxically, the thymidine kinase (TK) encoded by Kaposi sarcoma-associated herpesvirus (KSHV) is an extremely inefficient nucleoside kinase, when compared to TKs from related herpesviruses. We now show that KSHV-TK, in contrast to HSV1-TK, associates with the actin cytoskeleton and induces extensive cell contraction followed by membrane blebbing. These dramatic changes in cell morphology depend on the auto-phosphorylation of tyrosines 65, 85 and 120 in the N-terminus of KSHV-TK. Phosphorylation of tyrosines 65/85 and 120 results in an interaction with Crk family proteins and the p85 regulatory subunit of PI3-Kinase, respectively. The interaction of Crk with KSHV-TK leads to tyrosine phoshorylation of this cellular adaptor. Auto-phosphorylation of KSHV-TK also induces a loss of FAK and paxillin from focal adhesions, resulting in activation of RhoA-ROCK signalling to myosin II and cell contraction. In the absence of FAK or paxillin, KSHV-TK has no effect on focal adhesion integrity or cell morphology. Our observations demonstrate that by acting as a tyrosine kinase, KSHV-TK modulates signalling and cell morphology. PMID:25471072

Morphology of Block Copolymer Electrolytes: A Numerical Self-Consistent Field Theory Study

NASA Astrophysics Data System (ADS)

Hou, Kevin; Qin, Jian

Engineering the morphology of ion-containing block copolymers is imperative for the optimization of their charge-transport and mechanical properties. Existing experiments have demonstrated that the addition of ions has a dramatic effect on the morphology and thermodynamic behavior of these structured electrolytes. We have developed an efficient, symmetry-adapted algorithm to calculate the ionic interactions in the SCFT for ion-containing polymers. We present the results of a numerical SCFT study examining how dielectric heterogeneity, ion concentration, and ion solvation affect morphology, domain spacing, ion distribution, and polymer density profiles. Particular attention is given to the detailed morphological analysis of the bicontinuous gyroidal phase, as well as the relevance of the aforementioned results to ionic conductivity.

Mitochondrial sequence divergence among Antarctic killer whale ecotypes is consistent with multiple species.

PubMed

LeDuc, Richard G; Robertson, Kelly M; Pitman, Robert L

2008-08-23

Recently, three visually distinct forms of killer whales (Orcinus orca) were described from Antarctic waters and designated as types A, B and C. Based on consistent differences in prey selection and habitat preferences, morphological divergence and apparent lack of interbreeding among these broadly sympatric forms, it was suggested that they may represent separate species. To evaluate this hypothesis, we compared complete sequences of the mitochondrial control region from 81 Antarctic killer whale samples, including 9 type A, 18 type B, 47 type C and 7 type-undetermined individuals. We found three fixed differences that separated type A from B and C, and a single fixed difference that separated type C from A and B. These results are consistent with reproductive isolation among the different forms, although caution is needed in drawing further conclusions. Despite dramatic differences in morphology and ecology, the relatively low levels of sequence divergence in Antarctic killer whales indicate that these evolutionary changes occurred relatively rapidly and recently.

Nanoparticle induced piezoelectric, super toughened, radiation resistant, multi-functional nanohybrids.

PubMed

Tiwari, Vimal K; Shripathi, T; Lalla, N P; Maiti, Pralay

2012-01-07

We have developed multifunctional nanohybrids of poly(vinylidene fluoride-co-chlorotrifluoroethylene) (CTFE) with a small percentage of surface modified inorganic layered silicate showing dramatic improvement in toughness, radiation resistant and piezoelectric properties vis-à-vis pristine polymer. Massive intercalation (d(001) 1.8 → 3.9 nm) of polymer inside the nanoclay galleries and unique crystallization behavior of the fluoropolymer on the surface of individual silicate layer has been reported. Toughness in the nanohybrid increases more than three orders of magnitude as compared to pure CTFE. High energy radiation (80 MeV Si(+7)) causes chain session, amorphization and creates olefinic bonds in the pure polymer while the nanohybrids are radiation resistant at a similar dose. Nanoclay induces the metastable piezoelectric β-phase in CTFE, suitable for sensor and actuator application. Molecular level changes after irradiation and controlled morphology for smart membrane have been confirmed by using spectroscopy, sol-gel technique, surface morphology studies and in situ residual gas analysis.

Investigations on Structural, Optical and X-Radiation Responsive Properties of a-Se Thin Films Fabricated by Thermal Evaporation Method at Low Vacuum Degree.

PubMed

Li, Jitao; Zhu, Xinghua; Yang, Dingyu; Gu, Peng; Wu, Haihua

2018-03-02

Amorphous selenium (a-Se) thin films with a thickness of 1200 nm were successfully fabricated by thermal evaporation at a low vacuum degree of 10 -2 Pa. The structural properties involving phase and morphology showed that a-Se thin films could be resistant to 60 °C in air. Also, a transformation to polycrystalline Selenium (p-Se) was shown as the annealing temperature rose to 62 °C and 65 °C, with obvious changes in color and surface morphology. Moreover, as the a-Se transformed to p-Se, the samples' transmittance decreased significantly, and the band gap declined dramatically from 2.15 eV to 1.92 eV. Finally, the X-radiation response of a-Se was investigated as an important property, revealing there is a remarkable response speed of photogeneration current both X-ray on and X-ray off, with a requirement of only a very small electrical field.

Two-dimensional nanowires on homoepitaxial interfaces: Atomic-scale mechanism of breakdown and disintegration

NASA Astrophysics Data System (ADS)

Michailov, Michail; Ranguelov, Bogdan

2018-03-01

We present a model for hole-mediated spontaneous breakdown of ahomoepitaxial two-dimensional (2D) flat nanowire based exclusively on random, thermally-activated motion of atoms. The model suggests a consecutive three-step mechanism driving the rupture and complete disintegration of the nanowire on a crystalline surface. The breakdown scenario includes: (i) local narrowing of a part of the stripe to a monatomic chain, (ii) formation of a recoverable single vacancy or a 2D vacancy cluster that causes temporary nanowire rupture, (iii) formation of a non-recoverable 2D hole leading to permanent nanowire breakdown. These successive events in the temporal evolution of the nanowire morphology bring the nanowire stripe into an irreversible unstable state, leading to a dramatic change in its peculiar physical properties and conductivity. The atomistic simulations also reveal a strong increase of the nanowire lifetime with an enlargement of its width and open up a way for a fine atomic-scale control of the nanowire lifetime and structural, morphological and thermodynamic stability.

[Morphological features of the myometrium in connective tissue dysplasia in women with uterine inertia].

PubMed

Konovalov, P V; Mitrofanova, L B; Gorshkov, A N; Ovsyannikov, F A

2015-01-01

to reveal the morphological features of the lower uterine segment myometrium in connective tissue dysplasia (CTD) in women with uterine inertia. Histological, immunohistochemical (with antibodies against collagen types I and III, matrix metalloproteinases 1 and 9 (MMR-1, MMP-9), tissue inhibitor of metalloproteinase 1 (TIMP-1), fibronectin; fibulin-5, connexin-43), electron microscopic, and electron immunocytochemical studies with morphometry of myometrial fragments from 15 parturient women with CTD and uterine inertia (a study group) and those from 10 women without CTD (a control group). The myometrium in CTD exhibited the decreased expression of connextin-43, fibulin-5, TIMP-1, collagens types I and III with collagen type III predominance and the unchanged levels of fibronectin and MMP-1 and MMP-9. Electron microscopy and immunocytochemistry showed fewer intercellular contacts and the dramatically lower expression of connexin-43 than in the control. A set of found myometrial changes in women with uterine inertia is a manifestation of CTD.

Calcium-Responsive Liposomes via a Synthetic Lipid Switch.

PubMed

Lou, Jinchao; Carr, Adam J; Watson, Alexa J; Mattern-Schain, Samuel I; Best, Michael D

2018-03-07

Liposomal drug delivery would benefit from enhanced control over content release. Here, we report a novel avenue for triggering release driven by chemical composition using liposomes sensitized to calcium-a target chosen due to its key roles in biology and disease. To demonstrate this principle, we synthesized calcium-responsive lipid switch 1, designed to undergo conformational changes upon calcium binding. The conformational change perturbs membrane integrity, thereby promoting cargo release. This was shown through fluorescence-based release assays via dose-dependent response depending on the percentage of 1 in liposomes, with minimal background leakage in controls. DLS experiments indicated dramatic changes in particle size upon treatment of liposomes containing 1 with calcium. In a comparison of ten naturally occurring metal cations, calcium provided the greatest release. Finally, STEM images showed significant changes in liposome morphology upon treatment of liposomes containing 1 with calcium. These results showcase lipid switches driven by molecular recognition principles as an exciting avenue for controlling membrane properties. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reversible changes in pancreatic islet structure and function produced by elevated blood glucose

PubMed Central

Brereton, Melissa F.; Iberl, Michaela; Shimomura, Kenju; Zhang, Quan; Adriaenssens, Alice E.; Proks, Peter; Spiliotis, Ioannis I.; Dace, William; Mattis, Katia K.; Ramracheya, Reshma; Gribble, Fiona M.; Reimann, Frank; Clark, Anne; Rorsman, Patrik; Ashcroft, Frances M.

2014-01-01

Diabetes is characterized by hyperglycaemia due to impaired insulin secretion and aberrant glucagon secretion resulting from changes in pancreatic islet cell function and/or mass. The extent to which hyperglycaemia per se underlies these alterations remains poorly understood. Here we show that β-cell-specific expression of a human activating KATP channel mutation in adult mice leads to rapid diabetes and marked alterations in islet morphology, ultrastructure and gene expression. Chronic hyperglycaemia is associated with a dramatic reduction in insulin-positive cells and an increase in glucagon-positive cells in islets, without alterations in cell turnover. Furthermore, some β-cells begin expressing glucagon, whilst retaining many β-cell characteristics. Hyperglycaemia, rather than KATP channel activation, underlies these changes, as they are prevented by insulin therapy and fully reversed by sulphonylureas. Our data suggest that many changes in islet structure and function associated with diabetes are attributable to hyperglycaemia alone and are reversed when blood glucose is normalized. PMID:25145789

Antiquity of the South Atlantic Anomaly and evidence for top-down control on the geodynamo

PubMed Central

Tarduno, John A.; Watkeys, Michael K.; Huffman, Thomas N.; Cottrell, Rory D.; Blackman, Eric G.; Wendt, Anna; Scribner, Cecilia A.; Wagner, Courtney L.

2015-01-01

The dramatic decay of dipole geomagnetic field intensity during the last 160 years coincides with changes in Southern Hemisphere (SH) field morphology and has motivated speculation of an impending reversal. Understanding these changes, however, has been limited by the lack of longer-term SH observations. Here we report the first archaeomagnetic curve from southern Africa (ca. 1000–1600 AD). Directions change relatively rapidly at ca. 1300 AD, whereas intensities drop sharply, at a rate greater than modern field changes in southern Africa, and to lower values. We propose that the recurrence of low field strengths reflects core flux expulsion promoted by the unusual core–mantle boundary (CMB) composition and structure beneath southern Africa defined by the African large low shear velocity province (LLSVP). Because the African LLSVP and CMB structure are ancient, this region may have been a steady site for flux expulsion, and triggering of geomagnetic reversals, for millions of years. PMID:26218786

Fast Kinetics of Calcium Signaling and Sensor Design

PubMed Central

Tang, Shen; Reddish, Florence; Zhuo, You; Yang, Jenny J.

2015-01-01

Fast calcium signaling is regulated by numerous calcium channels exhibiting high spatiotemporal profiles which are currently measured by fluorescent calcium sensors. There is still a strong need to improve the kinetics of genetically encoded calcium indicators (sensors) to capture calcium dynamics in the millisecond time frame. In this review, we summarize several major fast calcium signaling pathways and discuss the recent developments and application of genetically encoded calcium indicators to detect these pathways. A new class of genetically encoded calcium indicators designed with site-directed mutagenesis on the surface of beta-barrel fluorescent proteins to form a pentagonal bipyramidal-like calcium binding domain dramatically accelerates calcium binding kinetics. Furthermore, novel genetically encoded calcium indicators with significantly increased fluorescent lifetime change are advantageous in deep-field imaging with high light-scattering and notable morphology change. PMID:26151819

AgCl-doped CdSe quantum dots with near-IR photoluminescence.

PubMed

Kotin, Pavel Aleksandrovich; Bubenov, Sergey Sergeevich; Mordvinova, Natalia Evgenievna; Dorofeev, Sergey Gennadievich

2017-01-01

We report the synthesis of colloidal CdSe quantum dots doped with a novel Ag precursor: AgCl. The addition of AgCl causes dramatic changes in the morphology of synthesized nanocrystals from spherical nanoparticles to tetrapods and finally to large ellipsoidal nanoparticles. Ellipsoidal nanoparticles possess an intensive near-IR photoluminescence ranging up to 0.9 eV (ca. 1400 nm). In this article, we explain the reasons for the formation of the ellipsoidal nanoparticles as well as the peculiarities of the process. The structure, Ag content, and optical properties of quantum dots are also investigated. The optimal conditions for maximizing both the reaction yield and IR photoluminescence quantum yield are found.

Bulk synthesis of polypyrrole nanofibers by a seeding approach.

PubMed

Zhang, Xinyu; Manohar, Sanjeev K

2004-10-13

The morphology of doped polypyrrole.Cl powder changes dramatically from granular to nanofibrillar when a very small amount (1-4 mg) of V2O5 nanofibers are added to a chemical oxidative polymerization of pyrrole in aq 1.0 M HCl using (NH4)2S2O8 as the oxidant. Unlike the polyaniline system, a key synthetic requirement in the polypyrrole system is for the seed template to be "active", i.e., to be capable of independently oxidizing the pyrrole monomer. Thin, strongly adherent films can be obtained on inert surfaces such as glass, plastics, etc., directly from the polymerization mixture without any bulk product isolation steps, significantly simplifying the processing of these nanofibers.

Fabrication of SrGe2 thin films on Ge (100), (110), and (111) substrates

NASA Astrophysics Data System (ADS)

Imajo, T.; Toko, K.; Takabe, R.; Saitoh, N.; Yoshizawa, N.; Suemasu, T.

2018-01-01

Semiconductor strontium digermanide (SrGe2) has a large absorption coefficient in the near-infrared light region and is expected to be useful for multijunction solar cells. This study firstly demonstrates the formation of SrGe2 thin films via a reactive deposition epitaxy on Ge substrates. The growth morphology of SrGe2 dramatically changed depending on the growth temperature (300-700 °C) and the crystal orientation of the Ge substrate. We succeeded in obtaining single-oriented SrGe2 using a Ge (110) substrate at 500 °C. Development on Si or glass substrates will lead to the application of SrGe2 to high-efficiency thin-film solar cells.

Progressive brain damage, synaptic reorganization and NMDA activation in a model of epileptogenic cortical dysplasia.

PubMed

Colciaghi, Francesca; Finardi, Adele; Nobili, Paola; Locatelli, Denise; Spigolon, Giada; Battaglia, Giorgio Stefano

2014-01-01

Whether severe epilepsy could be a progressive disorder remains as yet unresolved. We previously demonstrated in a rat model of acquired focal cortical dysplasia, the methylazoxymethanol/pilocarpine - MAM/pilocarpine - rats, that the occurrence of status epilepticus (SE) and subsequent seizures fostered a pathologic process capable of modifying the morphology of cortical pyramidal neurons and NMDA receptor expression/localization. We have here extended our analysis by evaluating neocortical and hippocampal changes in MAM/pilocarpine rats at different epilepsy stages, from few days after onset up to six months of chronic epilepsy. Our findings indicate that the process triggered by SE and subsequent seizures in the malformed brain i) is steadily progressive, deeply altering neocortical and hippocampal morphology, with atrophy of neocortex and CA regions and progressive increase of granule cell layer dispersion; ii) changes dramatically the fine morphology of neurons in neocortex and hippocampus, by increasing cell size and decreasing both dendrite arborization and spine density; iii) induces reorganization of glutamatergic and GABAergic networks in both neocortex and hippocampus, favoring excitatory vs inhibitory input; iv) activates NMDA regulatory subunits. Taken together, our data indicate that, at least in experimental models of brain malformations, severe seizure activity, i.e., SE plus recurrent seizures, may lead to a widespread, steadily progressive architectural, neuronal and synaptic reorganization in the brain. They also suggest the mechanistic relevance of glutamate/NMDA hyper-activation in the seizure-related brain pathologic plasticity.

[Impact of compounded chelants on removal of heavy metals and characteristics of morphologic change in soil from heavy metals contaminated sites].

PubMed

Yin, Xue; Chen, Jia-Jun; Lü, Ce

2014-02-01

Na2 EDTA (EDTA) has been extensively applied in remediation of soil contaminated by heavy metals (HMs). However, it poses a threat to the environment due to its difficulty of degradation. In addition, it is of great importance to clarify the morphological distribution of these metals in soil, as it is related to the environmental risk of contaminated sites. Thus, in order to cut back the use of EDTA, a series of batch washing experiments were conducted to evaluate the removal of arsenic, cadmium, copper, and lead from the contaminated soil collected in a chemical plant. Furthermore, adopting the optimal ratio of EDTA/EDDS, the change of morphological distribution of HMs before and after washing was studied. The results indicated that the removal of arsenic, cadmium and lead reached the maximum when the ratio of EDTA/EDDS was 7:3 and the optimal value was 12.67%, 38.71% and 31.09%, respectively. The removal of copper reached 16.91% at an EDTA/EDDS ratio of 9:1. After washing, the absolute Fe-Mn oxide fraction concentration of arsenic was higher, which would increase the environmental risk; the morphological fraction distribution of cadmium was similar to the original soil; the removal of copper and lead was mainly derived from the Fe-Mn oxide fraction; as to lead, the absolute concentration of Fe-Mn oxide fraction decreased dramatically, was and the same was observed for the percentage in the organic fraction. Employing the compounded system, the removal of HMs could be improved, and meanwhile the amounts of bioavailable HMs declined. Hence, it is beneficial for providing theoretical support for HMs remediation.

Shiga Toxin Mediated Neurologic Changes in Murine Model of Disease.

PubMed

Pradhan, Suman; Pellino, Christine; MacMaster, Kayleigh; Coyle, Dennis; Weiss, Alison A

2016-01-01

Seizures and neurologic involvement have been reported in patients infected with Shiga toxin (Stx) producing E. coli , and hemolytic uremic syndrome (HUS) with neurologic involvement is associated with more severe outcome. We investigated the extent of renal and neurologic damage in mice following injection of the highly potent form of Stx, Stx2a, and less potent Stx1. As observed in previous studies, Stx2a brought about moderate to acute tubular necrosis of proximal and distal tubules in the kidneys. Brain sections stained with hematoxylin and eosin (H&E) appeared normal, although some red blood cell congestion was observed. Microglial cell responses to neural injury include up-regulation of surface-marker expression (e.g., Iba1) and stereotypical morphological changes. Mice injected with Stx2a showed increased Iba1 staining, mild morphological changes associated with microglial activation (thickening of processes), and increased microglial staining per unit area. Microglial changes were observed in the cortex, hippocampus, and amygdala regions, but not the nucleus. Magnetic resonance imaging (MRI) of Stx2a-treated mice revealed no hyper-intensities in the brain, although magnetic resonance spectroscopy (MRS) revealed significantly decreased levels of phosphocreatine in the thalamus. Less dramatic changes were observed following Stx1 challenge. Neither immortalized microvascular endothelial cells from the cerebral cortex of mice (bEnd.3) nor primary human brain microvascular endothelial cells were found to be susceptible to Stx1 or Stx2a. The lack of susceptibility to Stx for both cell types correlated with an absence of receptor expression. These studies indicate Stx causes subtle, but identifiable changes in the mouse brain.

The genome of the Gulf pipefish enables understanding of evolutionary innovations.

PubMed

Small, C M; Bassham, S; Catchen, J; Amores, A; Fuiten, A M; Brown, R S; Jones, A G; Cresko, W A

2016-12-20

Evolutionary origins of derived morphologies ultimately stem from changes in protein structure, gene regulation, and gene content. A well-assembled, annotated reference genome is a central resource for pursuing these molecular phenomena underlying phenotypic evolution. We explored the genome of the Gulf pipefish (Syngnathus scovelli), which belongs to family Syngnathidae (pipefishes, seahorses, and seadragons). These fishes have dramatically derived bodies and a remarkable novelty among vertebrates, the male brood pouch. We produce a reference genome, condensed into chromosomes, for the Gulf pipefish. Gene losses and other changes have occurred in pipefish hox and dlx clusters and in the tbx and pitx gene families, candidate mechanisms for the evolution of syngnathid traits, including an elongated axis and the loss of ribs, pelvic fins, and teeth. We measure gene expression changes in pregnant versus non-pregnant brood pouch tissue and characterize the genomic organization of duplicated metalloprotease genes (patristacins) recruited into the function of this novel structure. Phylogenetic inference using ultraconserved sequences provides an alternative hypothesis for the relationship between orders Syngnathiformes and Scombriformes. Comparisons of chromosome structure among percomorphs show that chromosome number in a pipefish ancestor became reduced via chromosomal fusions. The collected findings from this first syngnathid reference genome open a window into the genomic underpinnings of highly derived morphologies, demonstrating that de novo production of high quality and useful reference genomes is within reach of even small research groups.

Methodological considerations for analyzing trabecular architecture: an example from the primate hand.

PubMed

Kivell, Tracy L; Skinner, Matthew M; Lazenby, Richard; Hublin, Jean-Jacques

2011-02-01

Micro-computed tomographic analyses of trabecular bone architecture have been used to clarify the link between positional behavior and skeletal anatomy in primates. However, there are methodological decisions associated with quantifying and comparing trabecular anatomy across taxa that vary greatly in body size and morphology that can affect characterizations of trabecular architecture, such as choice of the volume of interest (VOI) size and location. The potential effects of these decisions may be amplified in small, irregular-shaped bones of the hands and feet that have more complex external morphology and more heterogeneous trabecular structure compared to, for example, the spherical epiphysis of the femoral head. In this study we investigate the effects of changes in VOI size and location on standard trabecular parameters in two bones of the hand, the capitate and third metacarpal, in a diverse sample of nonhuman primates that vary greatly in morphology, body mass and positional behavior. Results demonstrate that changes in VOI location and, to a lesser extent, changes in VOI size had a dramatic affect on many trabecular parameters, especially trabecular connectivity and structure (rods vs. plates), degree of anisotropy, and the primary orientation of the trabeculae. Although previous research has shown that some trabecular parameters are susceptible to slight variations in methodology (e.g. VOI location, scan resolution), this study provides a quantification of these effects in hand bones of a diverse sample of primates. An a priori understanding of the inherent biases created by the choice of VOI size and particularly location is critical to robust trabecular analysis and functional interpretation, especially in small bones with complex arthroses. © 2010 The Authors. Journal of Anatomy © 2010 Anatomical Society of Great Britain and Ireland.

Programmed cell death during development of cowpea (Vigna unguiculata (L.) Walp.) seed coat.

PubMed

Lima, Nathália Bastos; Trindade, Fernanda Gomes; da Cunha, Maura; Oliveira, Antônia Elenir Amâncio; Topping, Jennifer; Lindsey, Keith; Fernandes, Kátia Valevski Sales

2015-04-01

The seed coat develops primarily from maternal tissues and comprises multiple cell layers at maturity, providing a metabolically dynamic interface between the developing embryo and the environment during embryogenesis, dormancy and germination of seeds. Seed coat development involves dramatic cellular changes, and the aim of this research was to investigate the role of programmed cell death (PCD) events during the development of seed coats of cowpea [Vigna unguiculata (L.) Walp.]. We demonstrate that cells of the developing cowpea seed coats undergo a programme of autolytic cell death, detected as cellular morphological changes in nuclei, mitochondria, chloroplasts and vacuoles, DNA fragmentation and oligonucleosome accumulation in the cytoplasm, and loss of membrane viability. We show for the first time that classes 6 and 8 caspase-like enzymes are active during seed coat development, and that these activities may be compartmentalized by translocation between vacuoles and cytoplasm during PCD events. © 2014 John Wiley & Sons Ltd.

Degradation of porous poly(D,L-lactic-co-glycolic acid) films based on water diffusion.

PubMed

Huang, Ying-Ying; Qi, Min; Liu, Hong-Ze; Zhao, Hong; Yang, Da-Zhi

2007-03-15

Poly(D,L-lactic-co-glycolic acid) has been extensively used as a controlled release carrier for drug delivery due to its good biocompatibility, biodegradability, and mechanical strength. Effects of dense and porous film's degradation behavior have been systematically investigated up to 17 weeks in Hank's Simulated Body Fluid at 37 degrees C. The degradation of the films was studied by measuring changes in weight, molecular weight and its distribution, morphology, composition etc.. A special thing was that the differences in water diffusion in dense and porous structure films caused the different degradation behavior. According to the characteristic changes of various properties of films, the degradation process is suggested to be roughly divided into four stages, tentatively named as water absorption stage, dramatic loss of molecular weight or micro-pores formed stage, loss of weight or enlarged-pores formed stage, pores diminished or pores collapse stage.

Effects of bioleaching on the mechanical and chemical properties of waste rocks

NASA Astrophysics Data System (ADS)

Yin, Sheng-Hua; Wu, Ai-Xiang; Wang, Shao-Yong; Ai, Chun-Ming

2012-01-01

Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks, and play an important role in metal recovery and dump stability. This study focused on the characteristics of waste rocks subjected to bioleaching. A series of experiments were conducted to investigate the evolution of rock properties during the bioleaching process. Mechanical behaviors of the leached waste rocks, such as failure patterns, normal stress, shear strength, and cohesion were determined through mechanical tests. The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump. The mineralogical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching. The dump porosity and rock size change under the effect of dissolution, precipitation, and clay transportation. The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles.

Changes in physicochemical properties of chitin at developmental stages (larvae, pupa and adult) of Vespa crabro (wasp).

PubMed

Kaya, Murat; Sofi, Karwan; Sargin, Idris; Mujtaba, Muhammad

2016-07-10

It is already known that chitin in a single organism can exhibit huge differences depending on the functions it serves in different body parts, but the alterations in the characteristics of chitin in course of developmental stages of an organism still remain unknown. This study presents findings on how chitin matrix is changing physicochemically through discrete morphological stages - larva, pupa and adult - of an insect (Vespa crabro). Chitin content of the organisms were found to increase gradually as the organism grew; 2.1, 6.2 and 10.3%, with a dramatic increase in chitin deposition (nearly 3 folds) during the instar from larva to pupa. Enzymatic digestion test demonstrated that chitin isolates were close to pure. Chitin isolates were also subjected to thermal pyrolysis and no variations were observed in the thermal stability of the samples. However, it was observed that surface characteristics of chitin changed greatly as the insect grew. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sporisorium reilianum Infection Changes Inflorescence and Branching Architectures of Maize1[C][W][OA

PubMed Central

Ghareeb, Hassan; Becker, Annette; Iven, Tim; Feussner, Ivo; Schirawski, Jan

2011-01-01

Sporisorium reilianum is a biotrophic maize (Zea mays) pathogen of increasing economic importance. Symptoms become obvious at flowering time, when the fungus causes spore formation and phyllody in the inflorescences. To understand how S. reilianum changes the inflorescence and floral developmental program of its host plant, we investigated the induced morphological and transcriptional alterations. S. reilianum infection promoted the outgrowth of subapical ears, suggesting that fungal presence suppressed apical dominance. Female inflorescences showed two distinct morphologies, here termed “leafy ear” and “eary ear.” In leafy ears, all floral organs were replaced by vegetative organs. In eary ears, modified carpels enclosed a new female inflorescence harboring additional female inflorescences at every spikelet position. Similar changes in meristem fate and organ identity were observed in the tassel of infected plants, which formed male inflorescences at spikelet positions. Thus, S. reilianum triggered a loss of organ and meristem identity and a loss of meristem determinacy in male and female inflorescences and flowers. Microarray analysis showed that these developmental changes were accompanied by transcriptional regulation of genes proposed to regulate floral organ and meristem identity as well as meristem determinacy in maize. S. reilianum colonization also led to a 30% increase in the total auxin content of the inflorescence as well as a dramatic accumulation of reactive oxygen species. We propose a model describing the architectural changes of infected inflorescence as a consequence of transcriptional, hormonal, and redox modulation, which will be the basis for further molecular investigation of the underlying mechanism of S. reilianum-induced alteration of floral development. PMID:21653782

Redefining metamorphosis in spiny lobsters: molecular analysis of the phyllosoma to puerulus transition in Sagmariasus verreauxi

PubMed Central

Ventura, Tomer; Fitzgibbon, Quinn P.; Battaglene, Stephen C.; Elizur, Abigail

2015-01-01

The molecular understanding of crustacean metamorphosis is hindered by small sized individuals and inability to accurately define molt stages. We used the spiny lobster Sagmariasus verreauxi where the large, transparent larvae enable accurate tracing of the transition from a leaf-shaped phyllosoma to an intermediate larval-juvenile phase (puerulus). Transcriptomic analysis of larvae at well-defined stages prior to, during, and following this transition show that the phyllosoma-puerulus metamorphic transition is accompanied by vast transcriptomic changes exceeding 25% of the transcriptome. Notably, genes previously identified as regulating metamorphosis in other crustaceans do not fluctuate during this transition but in the later, morphologically-subtle puerulus-juvenile transition, indicating that the dramatic phyllosoma-puerulus morphological shift relies on a different, yet to be identified metamorphic mechanism. We examined the change in expression of domains and gene families, with focus on several key genes. Our research implies that the separation in molecular triggering systems between the phyllosoma-puerulus and puerulus-juvenile transitions might have enabled the extension of the oceanic phase in spiny lobsters. Study of similar transitions, where metamorphosis is uncoupled from the transition into the benthic juvenile form, in other commercially important crustacean groups might show common features to point on the evolutionary advantage of this two staged regulation. PMID:26311524

Redefining metamorphosis in spiny lobsters: molecular analysis of the phyllosoma to puerulus transition in Sagmariasus verreauxi.

PubMed

Ventura, Tomer; Fitzgibbon, Quinn P; Battaglene, Stephen C; Elizur, Abigail

2015-08-27

The molecular understanding of crustacean metamorphosis is hindered by small sized individuals and inability to accurately define molt stages. We used the spiny lobster Sagmariasus verreauxi where the large, transparent larvae enable accurate tracing of the transition from a leaf-shaped phyllosoma to an intermediate larval-juvenile phase (puerulus). Transcriptomic analysis of larvae at well-defined stages prior to, during, and following this transition show that the phyllosoma-puerulus metamorphic transition is accompanied by vast transcriptomic changes exceeding 25% of the transcriptome. Notably, genes previously identified as regulating metamorphosis in other crustaceans do not fluctuate during this transition but in the later, morphologically-subtle puerulus-juvenile transition, indicating that the dramatic phyllosoma-puerulus morphological shift relies on a different, yet to be identified metamorphic mechanism. We examined the change in expression of domains and gene families, with focus on several key genes. Our research implies that the separation in molecular triggering systems between the phyllosoma-puerulus and puerulus-juvenile transitions might have enabled the extension of the oceanic phase in spiny lobsters. Study of similar transitions, where metamorphosis is uncoupled from the transition into the benthic juvenile form, in other commercially important crustacean groups might show common features to point on the evolutionary advantage of this two staged regulation.

Three-dimensional analysis of synapses in the transentorhinal cortex of Alzheimer's disease patients.

PubMed

Domínguez-Álvaro, M; Montero-Crespo, M; Blazquez-Llorca, L; Insausti, R; DeFelipe, J; Alonso-Nanclares, L

2018-03-02

Synaptic dysfunction or loss in early stages of Alzheimer's disease (AD) is thought to be a major structural correlate of cognitive dysfunction. Early loss of episodic memory, which occurs at the early stage of AD, is closely associated with the progressive degeneration of medial temporal lobe (MTL) structures of which the transentorhinal cortex (TEC) is the first affected area. However, no ultrastructural studies have been performed in this region in human brain samples from AD patients. In the present study, we have performed a detailed three-dimensional (3D) ultrastructural analysis using focused ion beam/scanning electron microscopy (FIB/SEM) to investigate possible synaptic alterations in the TEC of patients with AD. Surprisingly, the analysis of the density, morphological features and spatial distribution of synapses in the neuropil showed no significant differences between AD and control samples. However, light microscopy studies showed that cortical thickness of the TEC was severely reduced in AD samples, but there were no changes in the volume occupied by neuronal and glial cell bodies, blood vessels, and neuropil. Thus, the present results indicate that there is a dramatic loss of absolute number of synapses, while the morphology of synaptic junctions and synaptic spatial distribution are maintained. How these changes affect cognitive impairment in AD remains to be elucidated.

A climate for speciation: rapid spatial diversification within the Sorex cinereus complex of shrews

USGS Publications Warehouse

Hope, Andrew G.; Speer, Kelly A.; Demboski, John R.; Talbot, Sandra L.; Cook, Joseph A.

2012-01-01

The cyclic climate regime of the late Quaternary caused dramatic environmental change at high latitudes. Although these events may have been brief in periodicity from an evolutionary standpoint, multiple episodes of allopatry and divergence have been implicated in rapid radiations of a number of organisms. Shrews of the Sorex cinereus complex have long challenged taxonomists due to similar morphology and parapatric geographic ranges. Here, multi-locus phylogenetic and demographic assessments using a coalescent framework were combined to investigate spatiotemporal evolution of 13 nominal species with a widespread distribution throughout North America and across Beringia into Siberia. For these species, we first test a hypothesis of recent differentiation in response to Pleistocene climate versus more ancient divergence that would coincide with pre-Pleistocene perturbations. We then investigate the processes driving diversification over multiple continents. Our genetic analyses highlight novel diversity within these morphologically conserved mammals and clarify relationships between geographic distribution and evolutionary history. Demography within and among species indicates both regional stability and rapid expansion. Ancestral ecological differentiation coincident with early cladogenesis within the complex enabled alternating and repeated episodes of allopatry and expansion where successive glacial and interglacial phases each promoted divergence. The Sorex cinereus complex constitutes a valuable model for future comparative assessments of evolution in response to cyclic environmental change.

Predation as the primary selective force in recurrent evolution of gigantism in Poecilozonites land snails in Quaternary Bermuda

PubMed Central

Olson, Storrs L.; Hearty, Paul J.

2010-01-01

During the last half million years, pulses of gigantism in the anagenetic lineage of land snails of the subgenus Poecilozonites on Bermuda were correlated with glacial periods when lower sea level resulted in an island nearly an order of magnitude larger than at present. During those periods, the island was colonized by large vertebrate predators that created selection pressure for large size and rapid growth in the snails. Extreme reduction in land area from rising seas, along with changes in ecological conditions at the onset of interglacial episodes, marked extinction events for large predators, after which snails reverted to much smaller size. The giant snails were identical in morphology during the last two glacials when the predators included a large flightless rail Rallus recessus (marine isotope stages (MIS) 4-2) and a crane Grus latipes and a duck Anas pachysceles (MIS 6). In a preceding glacial period (MIS 10), when the fauna also included the tortoise Hesperotestudo bermudae, the snails were not only large, but the shells were much thicker, presumably to prevent crushing by tortoises. Evolution of Poecilozonites provides an outstanding example of dramatic morphological change in response to environmental pressures in the absence of cladogenesis. PMID:20554560

Overexpression of MAP2 and NF-H Associated with Dendritic Pathology in the Spinal Cord of Mice Infected with Rabies Virus

PubMed Central

Santamaría, Gerardo; Torres-Fernández, Orlando

2018-01-01

Rabies is a viral infection that targets the nervous system, specifically neurons. The clinical manifestations of the disease are dramatic and their outcome fatal; paradoxically, conventional histopathological descriptions reveal only subtle changes in the affected nervous tissue. Some researchers have considered that the pathophysiology of rabies is based more on biochemical changes than on structural alterations, as is the case with some psychiatric diseases. However, we believe that it has been necessary to resort to other methods that allow us to analyze the effect of the infection on neurons. The Golgi technique is the gold standard for studying the morphology of all the components of a neuron and the cytoskeletal proteins are the structural support of dendrites and axons. We have previously shown, in the mouse cerebral cortex and now with this work in spinal cord, that rabies virus generates remarkable alterations in the morphological pattern of the neurons and that this effect is associated with the increase in the expression of two cytoskeletal proteins (MAP2 and NF-H). It is necessary to deepen the investigation of the pathogenesis of rabies in order to find therapeutic alternatives to a disease to which the World Health Organization classifies as a neglected disease. PMID:29509660

Fabrication of SrGe2 thin films on Ge (100), (110), and (111) substrates.

PubMed

Imajo, T; Toko, K; Takabe, R; Saitoh, N; Yoshizawa, N; Suemasu, T

2018-01-16

Semiconductor strontium digermanide (SrGe 2 ) has a large absorption coefficient in the near-infrared light region and is expected to be useful for multijunction solar cells. This study firstly demonstrates the formation of SrGe 2 thin films via a reactive deposition epitaxy on Ge substrates. The growth morphology of SrGe 2 dramatically changed depending on the growth temperature (300-700 °C) and the crystal orientation of the Ge substrate. We succeeded in obtaining single-oriented SrGe 2 using a Ge (110) substrate at 500 °C. Development on Si or glass substrates will lead to the application of SrGe 2 to high-efficiency thin-film solar cells.

Domains in Ferroelectric Nanostructures

NASA Astrophysics Data System (ADS)

Gregg, Marty

2010-03-01

Ferroelectric materials have great potential in influencing the future of small scale electronics. At a basic level, this is because ferroelectric surfaces are charged, and so interact strongly with charge-carrying metals and semiconductors - the building blocks for all electronic systems. Since the electrical polarity of the ferroelectric can be reversed, surfaces can both attract and repel charges in nearby materials, and can thereby exert complete control over both charge distribution and movement. It should be no surprise, therefore, that microelectronics industries have already looked very seriously at harnessing ferroelectric materials in a variety of applications, from solid state memory chips (FeRAMs) to field effect transistors (FeFETs). In all such applications, switching the direction of the polarity of the ferroelectric is a key aspect of functional behavior. The mechanism for switching involves the field-induced nucleation and growth of domains. Domain coarsening, through domain wall propagation, eventually causes the entire ferroelectric to switch its polar direction. It is thus the existence and behavior of domains that determine the switching response, and ultimately the performance of the ferroelectric device. A major issue, associated with the integration of ferroelectrics into microelectronic devices, has been that the fundamental properties associated with ferroelectrics, when in bulk form, appear to change quite dramatically and unpredictably when at the nanoscale: new modes of behaviour, and different functional characteristics from those seen in bulk appear. For domains, in particular, the proximity of surfaces and boundaries have a dramatic effect: surface tension and depolarizing fields both serve to increase the equilibrium density of domains, such that minor changes in scale or morphology can have major ramifications for domain redistribution. Given the importance of domains in dictating the overall switching characteristics of a device, the need to fully understand how size and morphology affect domain behaviour in small scale ferroelectrics is obvious. In this talk, observations from a programme of study examining domains in meso and nano-scale BaTiO3 shapes, that have been cut directly from bulk single crystal using focused ion beam milling, will be presented. In general, the equilibrium static domain configurations that occur appear to be the result of a simultaneous desire to minimize both the macroscopic strain and depolarizing fields developed on cooling through the Curie Temperature. While such governing factors might be obvious, the specific patterns that result as a function of morphology are often non-intuitive, and a series of images of domains in nanodots, rods and wires will be presented and rationalised. In addition, the nature in which morphological factors influence domain dynamics during switching will be discussed, with particular focus on axial switching in nanowires, and the manner in which local surface perturbations (such as notches and antinotches) affect domain wall propagation. In collaboration with Alina Schilling, Li-Wu Chang, Mark McMillen, Raymond McQuaid, and Leo McGilly, Queen's University Belfast; Gustau Catalan, Universitat Autonoma de Barcelona; and James Scott, University of Cambridge.

Degradation of Methylammonium Lead Iodide Perovskite Structures through Light and Electron Beam Driven Ion Migration

PubMed Central

2016-01-01

Organometal halide perovskites show promising features for cost-effective application in photovoltaics. The material instability remains a major obstacle to broad application because of the poorly understood degradation pathways. Here, we apply simultaneous luminescence and electron microscopy on perovskites for the first time, allowing us to monitor in situ morphology evolution and optical properties upon perovskite degradation. Interestingly, morphology, photoluminescence (PL), and cathodoluminescence of perovskite samples evolve differently upon degradation driven by electron beam (e-beam) or by light. A transversal electric current generated by a scanning electron beam leads to dramatic changes in PL and tunes the energy band gaps continuously alongside film thinning. In contrast, light-induced degradation results in material decomposition to scattered particles and shows little PL spectral shifts. The differences in degradation can be ascribed to different electric currents that drive ion migration. Moreover, solution-processed perovskite cuboids show heterogeneity in stability which is likely related to crystallinity and morphology. Our results reveal the essential role of ion migration in perovskite degradation and provide potential avenues to rationally enhance the stability of perovskite materials by reducing ion migration while improving morphology and crystallinity. It is worth noting that even moderate e-beam currents (86 pA) and acceleration voltages (10 kV) readily induce significant perovskite degradation and alter their optical properties. Therefore, attention has to be paid while characterizing such materials using scanning electron microscopy or transmission electron microscopy techniques. PMID:26804213

Polymer Nanocomposites: Insights from Theory and Molecular Simulations

NASA Astrophysics Data System (ADS)

Pani, Rakhee

Advantages of polymer nanocomposites have attracted great industrial attention due to their multifunctionality and innovative technological properties. Addition of small amount of nanoparticle (nanospheres, nanotubes, nanorods, nanoplatelets, or sheets) to polymer matrix cause dramatic improvement in structural and functional properties, which is difficult to attain from those of individual components. The interaction between polymer and nanoparticle create bulk materials dominated by solid state physics at the nanoscale. Furthermore, morphology of nanocomposites depends on structural arrangements of nanoparticles. Thus, for achievement of optimized functionality like electrical, optical, mechanical and thermal properties control over the dispersion of the nanoparticle is essential. However, properties of polymer nanocomposites depend on morphology control and nature of interfacial interactions. In order to control the morphology it is necessary to understand how the processing conditions, shape and size of nanoparticle influence the structure of composite. Molecular simulations can help us to predict the parameters that control the structural changes and we could design polymer nanocomposite entailing their end-use. In this work, we addressed the following research questions: (1) the dependence of nanoparticle ligand corona structure on solvent quality and (2) the role of interfacial energy and interactions on the dispersion of molecules and nanoparticles. Specifically, this research assessed the effect of solvent interactions on the structure of nanoparticles on the example of redox core encapsulating dendrimer and ligand functionalized gold nanoparticles, role of chemical interaction on solubility of glucose in ionic liquids, diffusion of fullerene nanoparticles in polymer matrix and influence of solubility parameters on the compatibility of gold nanoparticles with diblock copolymers. Computational methods allow quantifying the structure and flexibility of the polymer chains, how energetics and surface tension change with chemical composition of the polymer/dendrimer blocks, influence of nanoparticle on structural properties of polymer and factors which may contribute to the phase separation of the polymer from nanoparticle. Interfacial characteristics are not only determined by the size-induced properties, but also the surface chemistry of the particles. Presence of solvent and the resultant interactions with the solvent are known to influence the morphology and prevent or induce aggregation of nanoparticles in polymers. We found that surface chemistry can induce change in the structure of dendrimers encapsulating a redox active core and change the solubility of the nanoparticles. The interactions between nanoparticles and polymers can also influence the morphology. We performed investigation on the role of orientation of fullerene derivatives and surface energy of polymer surface which may induce the aggregation of the fullerene nanoparticles. Furthermore, we used quantitative measurements like cluster analysis to understand the most probable orientation of the fullerene derivative with respect to the polymer chains and the diffusion of the fullerene nanoparticle, which is related to the efficiency of solar cells, can change on presence of regiorandom and regioregular polymer chains. Furthermore, we have also used different solvents based on their Hildebrand solubility parameters to investigate factors governing the morphology of polymer nanocomposite via solvent interactions. We showed that change in solvent interactions affect the compatibility, aggregation/dispersion of the gold nanoparticles, which will directly affect the morphology of polymer matrix and structural aspects which can impact their functionality. Overall, our research indicated that solvent interaction play a role in controlling the morphology of polymer nanocomposite and solubility parameter can help us to predict the resulting morphology.

Self-organization of colloidal PbS quantum dots into highly ordered superlattices.

PubMed

Baranov, Alexander V; Ushakova, Elena V; Golubkov, Valery V; Litvin, Aleksandr P; Parfenov, Peter S; Fedorov, Anatoly V; Berwick, Kevin

2015-01-13

X-ray structural analysis, together with steady-state and transient optical spectroscopy, is used for studying the morphology and optical properties of quantum dot superlattices (QDSLs) formed on glass substrates by the self-organization of PbS quantum dots with a variety of surface ligands. The diameter of the PbS QDs varies from 2.8 to 8.9 nm. The QDSL's period is proportional to the dot diameter, increasing slightly with dot size due to the increase in ligand layer thickness. Removal of the ligands has a number of effects on the morphology of QDSLs formed from the dots of different sizes: for small QDs the reduction in the amount of ligands obstructs the self-organization process, impairing the ordering of the QDSLs, while for large QDs the ordering of the superlattice structure is improved, with an interdot distance as low as 0.4 nm allowing rapid charge carrier transport through the QDSLs. QDSL formation does not induce significant changes to the absorption and photoluminescence spectra of the QDs. However, the luminescence decay time is reduced dramatically, due to the appearance of nonradiative relaxation channels.

Advanced Tools for River Science: EAARL and MD_SWMS: Chapter 3

USGS Publications Warehouse

Kinzel, Paul J.

2009-01-01

Disruption of flow regimes and sediment supplies, induced by anthropogenic or climatic factors, can produce dramatic alterations in river form, vegetation patterns, and associated habitat conditions. To improve habitat in these fluvial systems, resource managers may choose from a variety of treatments including flow and/or sediment prescriptions, vegetation management, or engineered approaches. Monitoring protocols developed to assess the morphologic response of these treatments require techniques that can measure topographic changes above and below the water surface efficiently, accurately, and in a standardized, cost-effective manner. Similarly, modeling of flow, sediment transport, habitat, and channel evolution requires characterization of river morphology for model input and verification. Recent developments by the U.S. Geological Survey with regard to both remotely sensed methods (the Experimental Advanced Airborne Research LiDAR; EAARL) and computational modeling software (the Multi-Dimensional Surface-Water Modeling System; MD_SWMS) have produced advanced tools for spatially explicit monitoring and modeling in aquatic environments. In this paper, we present a pilot study conducted along the Platte River, Nebraska, that demonstrates the combined use of these river science tools.

Enhanced adherence of mouse fibroblast and vascular cells to plasma modified polyethylene.

PubMed

Reznickova, Alena; Novotna, Zdenka; Kolska, Zdenka; Kasalkova, Nikola Slepickova; Rimpelova, Silvie; Svorcik, Vaclav

2015-01-01

Since the last decade, tissue engineering has shown a sensational promise in providing more viable alternatives to surgical procedures for harvested tissues, implants and prostheses. Biomedical polymers, such as low-density polyethylene (LDPE), high-density polyethylene (HDPE) and ultra-high molecular weight polyethylene (UHMWPE), were activated by Ar plasma discharge. Degradation of polymer chains was examined by determination of the thickness of ablated layer. The amount of an ablated polymer layer was measured by gravimetry. Contact angle, measured by goniometry, was studied as a function of plasma exposure and post-exposure aging times. Chemical structure of modified polymers was characterized by angle resolved X-ray photoelectron spectroscopy. Surface chemistry and polarity of the samples were investigated by electrokinetic analysis. Changes in surface morphology were followed using atomic force microscopy. Cytocompatibility of plasma activated polyethylene foils was studied using two distinct model cell lines; VSMCs (vascular smooth muscle cells) as a model for vascular graft testing and connective tissue cells L929 (mouse fibroblasts) approved for standardized material cytotoxicity testing. Specifically, the cell number, morphology, and metabolic activity of the adhered and proliferated cells on the polyethylene matrices were studied in vitro. It was found that the plasma treatment caused ablation of the polymers, resulting in dramatic changes in their surface morphology and roughness. ARXPS and electrokinetic measurements revealed oxidation of the polymer surface. It was found that plasma activation has a positive effect on the adhesion and proliferation of VSMCs and L929 cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Sexually dimorphic responses to neonatal basal forebrain lesions in mice: I. Behavior and neurochemistry.

PubMed

Arters, J; Hohmann, C F; Mills, J; Olaghere, O; Berger-Sweeney, J

1998-12-01

The nucleus basalis magnocellularis (nBM) provides the primary source of cholinergic input to the cortex. Neonatal lesions of the nBM produce transient reductions in cholinergic markers, persistent abnormalities in cortical morphology, and spatial navigation impairments in adult mice. The present study examined sex differences in the effects of an electrolytic nBM lesion on postnatal day 1 (PND 1) in mice on behavior and neurochemistry in adulthood. Mice were lesioned on PND 1 and tested at 8 weeks of age on a battery of behavioral tests including passive avoidance, cued and spatial tasks in the Morris water maze, simple and delayed nonmatch to sample versions of an odor discrimination task, and locomotor activity measurements. Following behavioral testing, mice were sacrificed for either morphological assessment or neurochemical analysis of a cholinergic marker or catecholamines. There were no lesion or sex differences in acquisition or retention of passive avoidance, performance of the odor discrimination tasks, or activity levels. Control mice showed a robust sex difference in performance of the spatial water maze task. The lesion produced a slight cued but more dramatic spatial navigation deficit in the water maze which affected only the male mice. Neurochemical analyses revealed no lesion-induced changes in either choline acetyltransferase activity or levels of norepinephrine or serotonin at the time of testing. The subsequent report shows a sex difference in lesion-induced changes in cortical morphology which suggests that sexually dimorphic cholinergic influences on cortical development are responsible for the behavioral deficits seen in this study.

Interplay between river dynamics and international borders: the Hirmand River between Iran and Afghanistan

NASA Astrophysics Data System (ADS)

Yousefi, Saleh; Keesstra, Saskia; Pourghasemi, Hamid Reza; Surian, Nicola; Mirzaee, Somayeh

2017-04-01

Fluvial dynamics in riverine borders can play an important role in political relationships between countries. Rivers move and evolve under the influence of natural processes and external drivers (e.g. land use change in river catchments). The Hirmand River is an important riverine border between Iran and Afghanistan. The present study shows the evolution and lateral shifting of the Hirmand River along the common international border (25.6 km) over a period of 6 decades (1955-2015). Seven data series of aerial photos, topographic maps and Landsat images were used to identify the land cover and morphological changes in the study reach. The land cover has changed dramatically on both sides of the border during the last 6 decades, especially in the Afghan part. Overall, 49% of all land surface changed its cover type, especially the area of agriculture and residential land contributed to that, with an increase in surface area of about 4931 ha and 561 ha, respectively. On the other hand, the natural cover and water bodies decreased to 38 % and 63 %, respectively. The impact of these land use changes on the morphological evolution of Hirmand River was investigated in 5 sub-reaches. We found an average decrease of the active channel width of 53% during 60 years and the average River Network Change Index for the whole study reach during 60 years was -1.25 m/yr. Deposition and narrowing turned out to be the main processes occurring within the study reach. Furthermore, due to natural riverine processes the Hirmand River has moved towards Afghanistan (37 m on average) and lateral shifting was found to be up to 1900 m in some sections.

Extracellular Control of Limb Regeneration

NASA Astrophysics Data System (ADS)

Calve, S.; Simon, H.-G.

Adult newts possess the ability to completely regenerate organs and appendages. Immediately after limb loss, the extracellular matrix (ECM) undergoes dramatic changes that may provide mechanical and biochemical cues to guide the formation of the blastema, which is comprised of uncommitted stem-like cells that proliferate to replace the lost structure. Skeletal muscle is a known reservoir for blastema cells but the mechanism by which it contributes progenitor cells is still unclear. To create physiologically relevant culture conditions for the testing of primary newt muscle cells in vitro, the spatio-temporal distribution of ECM components and the mechanical properties of newt muscle were analyzed. Tenascin-C and hyaluronic acid (HA) were found to be dramatically upregulated in the amputated limb and were co-expressed around regenerating skeletal muscle. The transverse stiffness of muscle measured in situ was used as a guide to generate silicone-based substrates of physiological stiffness. Culturing newt muscle cells under different conditions revealed that the cells are sensitive to both matrix coating and substrate stiffness: Myoblasts on HA-coated soft substrates display a rounded morphology and become more elongated as the stiffness of the substrate increases. Coating of soft substrates with matrigel or fibronectin enhanced cell spreading and eventual cell fusion.

Impact of reaction conditions on grafting acrylamide onto starch

USDA-ARS?s Scientific Manuscript database

We have explored the radical initiated graft polymerization reaction of acrylamide onto starch where the solvent, concentration, temperature and reaction times were varied. We have found that the morphology of the resulting grafted polymer is dramatically different and is dependent on the reaction c...

Modeling attitude towards drug treament: the role of internal motivation, external pressure, and dramatic relief.

PubMed

Conner, Bradley T; Longshore, Douglas; Anglin, M Douglas

2009-04-01

Motivation for change has historically been viewed as the crucial element affecting responsiveness to drug treatment. Various external pressures, such as legal coercion, may engender motivation in an individual previously resistant to change. Dramatic relief may be the change process that is most salient as individuals internalize such external pressures. Results of structural equation modeling on data from 465 drug users (58.9% male; 21.3% Black, 34.2% Hispanic/Latino, and 35.1% White) entering drug treatment indicated that internal motivation and external pressure significantly and positively predicted dramatic relief and that dramatic relief significantly predicted attitudes towards drug treatment: chi (2) = 142.20, df = 100, p < 0.01; Robust Comparative Fit Index = 0.97, Root Mean Squared Error of Approximation = 0.03. These results indicate that when external pressure and internal motivation are high, dramatic relief is also likely to be high. When dramatic relief is high, attitudes towards drug treatment are likely to be positive. The findings indicate that interventions to get individuals into drug treatment should include processes that promote Dramatic Relief. Implications for addictions health services are discussed.

The preparation of large surface area lanthanum based perovskite supports for AuPt nanoparticles: tuning the glycerol oxidation reaction pathway by switching the perovskite B site

PubMed Central

Evans, Christopher D.; Smith, Paul J.; Manning, Troy D.; Miedziak, Peter J.; Brett, Gemma L.; Armstrong, Robert D.; Bartley, Jonathan K.; Taylor, Stuart H.; Rosseinsky, Matthew J.; Hutchings, Graham J.

2016-01-01

Gold and gold alloys, in the form of supported nanoparticles, have been shown over the last three decades to be highly effective oxidation catalysts. Mixed metal oxide perovskites, with their high structural tolerance, are ideal for investigating how changes in the chemical composition of supports affect the catalysts' properties, while retaining similar surface areas, morphologies and metal co-ordinations. However, a significant disadvantage of using perovskites as supports is their high crystallinity and small surface area. We report the use of a supercritical carbon dioxide anti-solvent precipitation methodology to prepare large surface area lanthanum based perovskites, making the deposition of 1 wt% AuPt nanoparticles feasible. These catalysts were used for the selective oxidation of glycerol. By changing the elemental composition of the perovskite B site, we dramatically altered the reaction pathway between a sequential oxidation route to glyceric or tartronic acid and a dehydration reaction pathway to lactic acid. Selectivity profiles were correlated to reported oxygen adsorption capacities of the perovskite supports and also to changes in the AuPt nanoparticle morphologies. Extended time on line analysis using the best oxidation catalyst (AuPt/LaMnO3) produced an exceptionally high tartronic acid yield. LaMnO3 produced from alternative preparation methods was found to have lower activities, but gave comparable selectivity profiles to that produced using the supercritical carbon dioxide anti-solvent precipitation methodology. PMID:27074316

The preparation of large surface area lanthanum based perovskite supports for AuPt nanoparticles: tuning the glycerol oxidation reaction pathway by switching the perovskite B site.

PubMed

Evans, Christopher D; Kondrat, Simon A; Smith, Paul J; Manning, Troy D; Miedziak, Peter J; Brett, Gemma L; Armstrong, Robert D; Bartley, Jonathan K; Taylor, Stuart H; Rosseinsky, Matthew J; Hutchings, Graham J

2016-07-04

Gold and gold alloys, in the form of supported nanoparticles, have been shown over the last three decades to be highly effective oxidation catalysts. Mixed metal oxide perovskites, with their high structural tolerance, are ideal for investigating how changes in the chemical composition of supports affect the catalysts' properties, while retaining similar surface areas, morphologies and metal co-ordinations. However, a significant disadvantage of using perovskites as supports is their high crystallinity and small surface area. We report the use of a supercritical carbon dioxide anti-solvent precipitation methodology to prepare large surface area lanthanum based perovskites, making the deposition of 1 wt% AuPt nanoparticles feasible. These catalysts were used for the selective oxidation of glycerol. By changing the elemental composition of the perovskite B site, we dramatically altered the reaction pathway between a sequential oxidation route to glyceric or tartronic acid and a dehydration reaction pathway to lactic acid. Selectivity profiles were correlated to reported oxygen adsorption capacities of the perovskite supports and also to changes in the AuPt nanoparticle morphologies. Extended time on line analysis using the best oxidation catalyst (AuPt/LaMnO3) produced an exceptionally high tartronic acid yield. LaMnO3 produced from alternative preparation methods was found to have lower activities, but gave comparable selectivity profiles to that produced using the supercritical carbon dioxide anti-solvent precipitation methodology.

Modelling morphology evolution during solidification of IPP in processing conditions

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

Pantani, R., E-mail: rpantani@unisa.it, E-mail: fedesantis@unisa.it, E-mail: vsperanza@unisa.it, E-mail: gtitomanlio@unisa.it; De Santis, F., E-mail: rpantani@unisa.it, E-mail: fedesantis@unisa.it, E-mail: vsperanza@unisa.it, E-mail: gtitomanlio@unisa.it; Speranza, V., E-mail: rpantani@unisa.it, E-mail: fedesantis@unisa.it, E-mail: vsperanza@unisa.it, E-mail: gtitomanlio@unisa.it

During polymer processing, crystallization takes place during or soon after flow. In most of cases, the flow field dramatically influences both the crystallization kinetics and the crystal morphology. On their turn, crystallinity and morphology affect product properties. Consequently, in the last decade, researchers tried to identify the main parameters determining crystallinity and morphology evolution during solidification In processing conditions. In this work, we present an approach to model flow-induced crystallization with the aim of predicting the morphology after processing. The approach is based on: interpretation of the FIC as the effect of molecular stretch on the thermodynamic crystallization temperature; modelingmore » the molecular stretch evolution by means of a model simple and easy to be implemented in polymer processing simulation codes; identification of the effect of flow on nucleation density and spherulites growth rate by means of simple experiments; determination of the condition under which fibers form instead of spherulites. Model predictions reproduce most of the features of final morphology observed in the samples after solidification.« less

Response of Halimeda to ocean acidification: Field and laboratory evidence

USGS Publications Warehouse

Robbins, L.L.; Knorr, P.O.; Hallock, P.

2009-01-01

Rising atmospheric pCO2 levels are changing ocean chemistry more dramatically now than in the last 20 million years. In fact, pHvalues of the open ocean have decreased by 0.1 since the 1800s and are predicted to decrease 0.1-0.4 globally in the next 90 years. Ocean acidification will affect fundamental geochemical and biological processes including calcification and carbonate sediment production. The west Florida shelf is a natural laboratory to examine the effects of ocean acidification on aragonite production by calcareous green algae. Scanning electron microscopy (SEM) of crystal morphology of calcifying organisms reveals ultrastructural details of calcification that occurred at different saturation states. Comparison of archived and recent specimens of calcareous green alga Halimeda spp. from the west Florida shelf, demonstrates crystal changes in shape and abundance over a 40+ year time span. Halimeda crystal data from apical sections indicate that increases in crystal concentration and decreases in crystal width occurred over the last 40+ years. Laboratory experiments using living specimens of Halimeda grown in environments with known pH values were used to constrain historical observations. Percentages of organic and inorganic carbon per sample weight of pooled species did not significantly change. However, individual species showed decreased inorganic carbon and increased organic carbon in more recent samples, although the sample sizes were limited. These results indicate that the effect of increased pCO 2 and decreased pH on calcification is reflected in the crystal morphology of this organism. More data are needed to confirm the observed changes in mass of crystal and organic carbon. ?? Author(s) 2009.

Competitive Adsorption-Assisted Formation of One-Dimensional Cobalt Nanochains with High CO Hydrogenation Activity

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

Liang, Xin; Ren, Zhibo; Zhu, Xiaolin

In the present work, cobalt nanochains have been successfully synthesized by a novel co assisted self-assembling formation strategy. A dramatic morphology transformation from cobalt nanoparticles to nanochains are observed when co molecules were introduced into the synthetic system. DFT calculations further confirm that competitive co-adsorbed co and oleylamine over the cobalt nanoparticles facilitates the formation of cobalt nanochains, which show higher co hydrogenation performance. The present work provides a new strategic and promising method for controllable synthesis of catalyst nanomaterials with the preferred surface structure and morphology.

Glucose-Induced Trophic Shift in an Endosymbiont Dinoflagellate with Physiological and Molecular Consequences1[OPEN

PubMed Central

Jinkerson, Robert E.; Clowez, Sophie; Onishi, Masayuki; Cleves, Phillip A.; Pringle, John R.

2018-01-01

Interactions between the dinoflagellate endosymbiont Symbiodinium and its cnidarian hosts (e.g. corals, sea anemones) are the foundation of coral-reef ecosystems. Carbon flow between the partners is a hallmark of this mutualism, but the mechanisms governing this flow and its impact on symbiosis remain poorly understood. We showed previously that although Symbiodinium strain SSB01 can grow photoautotrophically, it can grow mixotrophically or heterotrophically when supplied with Glc, a metabolite normally transferred from the alga to its host. Here we show that Glc supplementation of SSB01 cultures causes a loss of pigmentation and photosynthetic activity, disorganization of thylakoid membranes, accumulation of lipid bodies, and alterations of cell-surface morphology. We used global transcriptome analyses to determine if these physiological changes were correlated with changes in gene expression. Glc-supplemented cells exhibited a marked reduction in levels of plastid transcripts encoding photosynthetic proteins, although most nuclear-encoded transcripts (including those for proteins involved in lipid synthesis and formation of the extracellular matrix) exhibited little change in their abundances. However, the altered carbon metabolism in Glc-supplemented cells was correlated with modest alterations (approximately 2x) in the levels of some nuclear-encoded transcripts for sugar transporters. Finally, Glc-bleached SSB01 cells appeared unable to efficiently populate anemone larvae. Together, these results suggest links between energy metabolism and cellular physiology, morphology, and symbiotic interactions. However, the results also show that in contrast to many other organisms, Symbiodinium can undergo dramatic physiological changes that are not reflected by major changes in the abundances of nuclear-encoded transcripts and thus presumably reflect posttranscriptional regulatory processes. PMID:29217594

ECTODERMAL WNT/β-CATENIN SIGNALING SHAPES THE MOUSE FACE

PubMed Central

Reid, Bethany S.; Yang, Hui; Melvin, Vida Senkus; Taketo, Makoto M.; Williams, Trevor

2010-01-01

The canonical Wnt/β-catenin pathway is an essential component of multiple developmental processes. To investigate the role of this pathway in the ectoderm during facial morphogenesis, we generated conditional β-catenin mouse mutants using a novel ectoderm-specific Cre recombinase transgenic line. Our results demonstrate that ablating or stabilizing β-catenin in the embryonic ectoderm causes dramatic changes in facial morphology. There are accompanying alterations in the expression of Fgf8 and Shh, key molecules that establish a signaling center critical for facial patterning, the frontonasal ectodermal zone (FEZ). These data indicate that Wnt/β-catenin signaling within the ectoderm is critical for facial development and further suggest that this pathway is an important mechanism for generating the diverse facial shapes of vertebrates during evolution. PMID:21087601

Investigation of the microstructure of Ni and B4C ceramic-metal mixtures obtained by cold spray coating and followed by laser cladding

NASA Astrophysics Data System (ADS)

Filippov, A. A.; Fomin, V. M.; Orishich, A. M.; Malikov, A. G.; Ryashin, N. S.; Golyshev, A. A.

2017-10-01

In the present work, a combined method is considered for the production of a metal-matrix composite coating based on Ni and B4C. The coating is created by consistently applied methods: cold spray and laser cladding. Main focus of this work aimed to microstructure of coatings, element content and morphology of laser tracks. At this stage, the authors focused on the interaction of the laser unit with the substance without affecting the layer-growing technology products. It is shown that coating has deformed particles of nickel and the significantly decreased content of ceramic particles B4C after cold spray. After laser cladding there are no boundaries between nickel and dramatically changes in ceramic particles.

Ancient DNA provides new insights into the evolutionary history of New Zealand's extinct giant eagle.

PubMed

Bunce, Michael; Szulkin, Marta; Lerner, Heather R L; Barnes, Ian; Shapiro, Beth; Cooper, Alan; Holdaway, Richard N

2005-01-01

Prior to human settlement 700 years ago New Zealand had no terrestrial mammals--apart from three species of bats--instead, approximately 250 avian species dominated the ecosystem. At the top of the food chain was the extinct Haast's eagle, Harpagornis moorei. H. moorei (10-15 kg; 2-3 m wingspan) was 30%-40% heavier than the largest extant eagle (the harpy eagle, Harpia harpyja), and hunted moa up to 15 times its weight. In a dramatic example of morphological plasticity and rapid size increase, we show that the H. moorei was very closely related to one of the world's smallest extant eagles, which is one-tenth its mass. This spectacular evolutionary change illustrates the potential speed of size alteration within lineages of vertebrates, especially in island ecosystems.

The high resolution mapping of the Venice Lagoon tidal network

NASA Astrophysics Data System (ADS)

Madricardo, Fantina; Foglini, Federica; Kruss, Aleksandra; Bellafiore, Debora; Trincardi, Fabio

2017-04-01

One of the biggest challenges of the direct observation of the ocean is to achieve a high resolution mapping of its seafloor morphology and benthic habitats. So far, sonars have mapped just 0.05% of the ocean floor with less than ten-meter resolution. The recent efforts of the scientific community have been devoted towards the mapping of both Deep Ocean and very shallow coastal areas. Coastal and transitional environments in particular undergo strong morphological changes due to natural and anthropogenic pressure. Nowadays, only about 5% of the seafloor of these environments † have been mapped: the shallowness of these environments has prevented the use of underwater acoustics to reveal their morphological features. The recent technological development of multibeam echosounder systems, however, enables these instruments to achieve very high performances also in such shallow environments. In this work, we present results and case studies of an extensive multibeam survey carried out in the Lagoon of Venice in 2013. The Lagoon of Venice is the biggest lagoon in the Mediterranean Sea with a surface of about 550 km2 and with an average depth of about 1 m. In the last century, the morphological and ecological properties of the lagoon changed dramatically: the surface of the salt marshes was reduced by 60% and some parts of the lagoon are deepening with a net sediment flux exiting from the inlets. Moreover, major engineering interventions are currently ongoing at the inlets (MOSE project). These changes at the inlets could affect substantially the lagoon environment. To understand and monitor the future evolution of the Lagoon of Venice, ISMAR within the project RITMARE (a National Research Programme funded by the Italian Ministry of University and Research) carried out an extensive survey, involving a team of more than 25 scientists, to collect high resolution (0.5 m) bathymetry of key study areas such as the tidal inlets and channels. Following a broad multidisciplinary approach, bathymetric and backscatter intensity data are now employed for geomorphologic studies, habitat mapping and modelling of evolution trends of this highly dynamical and complex transitional environment.

Coupled dynamics of body mass and population growth in response to environmental change

PubMed Central

Ozgul, Arpat; Childs, Dylan Z.; Oli, Madan K.; Armitage, Kenneth B.; Blumstein, Daniel T.; Olson, Lucretia E.; Tuljapurkar, Shripad; Coulson, Tim

2017-01-01

Environmental change has altered the phenology, morphological traits and population dynamics of many species1,2. However, the links underlying these joint responses remain largely unknown due to a paucity of long-term data and the lack of an appropriate analytical framework3. Here, we investigate the link between phenotypic and demographic responses to environmental change using a novel methodology and an exceptional long-term (1976–2008) dataset from a hibernating mammal (the yellow-bellied marmot) inhabiting a dynamic subalpine habitat. We demonstrate how earlier emergence from hibernation and earlier weaning of young has led to a longer growing season and larger body masses prior to hibernation. The resulting shift in both the phenotype and the relationship between phenotype and fitness components led to a decline in adult mortality, which in turn triggered an abrupt increase in population size in recent years. Direct and trait-mediated effects of environmental change had comparable contributions to the observed dramatic increase in population growth. Our results help explain how a shift in phenology can cause simultaneous phenotypic and demographic changes, and highlight the need for a theory integrating ecological and evolutionary dynamics in stochastic environments4,5. PMID:20651690

Agatharesinol biosynthesis-related changes of ray parenchyma in sapwood sticks of Cryptomeria japonica during cell death.

PubMed

Nakaba, Satoshi; Arakawa, Izumi; Morimoto, Hikaru; Nakada, Ryogo; Bito, Nobumasa; Imai, Takanori; Funada, Ryo

2016-05-01

The work demonstrates a relationship between the biosynthesis of the secondary metabolite, agatharesinol, and cytological changes that occur in ray parenchyma during cell death in sapwood sticks of Cryptomeria japonica under humidity-regulated conditions. To characterize the death of ray parenchyma cells that accompanies the biosynthesis of secondary metabolites, we examined cell death in sapwood sticks of Cryptomeria japonica under humidity-regulated conditions. We monitored features of ray parenchyma cells, such as viability, the morphology of nuclei and vacuoles, and the amount of starch grains. In addition, we analyzed levels of agatharesinol, a heartwood norlignan, by gas chromatography-mass spectrometry in the same sapwood sticks. Dramatic changes in the amount of starch grains and in the level of agatharesinol occurred simultaneously. Therefore, the biosynthesis of agatharesinol appeared to originate from the breakdown of starch. Furthermore, we observed the expansion of vacuoles in ray parenchyma cells prior to other cytological changes at the final stage of cell death. In our experimental system, we were able to follow the process of cell death and to demonstrate relationships between cytological changes and the biosynthesis of a secondary metabolite during the death of ray parenchyma cells.

Multi-temporal database of High Resolution Stereo Camera (HRSC) images - Alpha version

NASA Astrophysics Data System (ADS)

Erkeling, G.; Luesebrink, D.; Hiesinger, H.; Reiss, D.; Jaumann, R.

2014-04-01

Image data transmitted to Earth by Martian spacecraft since the 1970s, for example by Mariner and Viking, Mars Global Surveyor (MGS), Mars Express (MEx) and the Mars Reconnaissance Orbiter (MRO) showed, that the surface of Mars has changed dramatically and actually is continually changing [e.g., 1-8]. The changes are attributed to a large variety of atmospherical, geological and morphological processes, including eolian processes [9,10], mass wasting processes [11], changes of the polar caps [12] and impact cratering processes [13]. In addition, comparisons between Mariner, Viking and Mars Global Surveyor images suggest that more than one third of the Martian surface has brightened or darkened by at least 10% [6]. Albedo changes can have effects on the global heat balance and the circulation of winds, which can result in further surface changes [14-15]. The High Resolution Stereo Camera (HRSC) [16,17] on board Mars Express (MEx) covers large areas at high resolution and is therefore suited to detect the frequency, extent and origin of Martian surface changes. Since 2003 HRSC acquires highresolution images of the Martian surface and contributes to Martian research, with focus on the surface morphology, the geology and mineralogy, the role of liquid water on the surface and in the atmosphere, on volcanism, as well as on the proposed climate change throughout the Martian history and has improved our understanding of the evolution of Mars significantly [18-21]. The HRSC data are available at ESA's Planetary Science Archive (PSA) as well as through the NASA Planetary Data System (PDS). Both data platforms are frequently used by the scientific community and provide additional software and environments to further generate map-projected and geometrically calibrated HRSC data. However, while previews of the images are available, there is no possibility to quickly and conveniently see the spatial and temporal availability of HRSC images in a specific region, which is important to detect the surface changes that occurred between two or more images.

Modeling Attitude towards Drug Treament: The Role of Internal Motivation, External Pressure, and Dramatic Relief

PubMed Central

Longshore, Douglas; Anglin, M. Douglas

2009-01-01

Motivation for change has historically been viewed as the crucial element affecting responsiveness to drug treatment. Various external pressures, such as legal coercion, may engender motivation in an individual previously resistant to change. Dramatic relief may be the change process that is most salient as individuals internalize such external pressures. Results of structural equation modeling on data from 465 drug users (58.9% male; 21.3% Black, 34.2% Hispanic/Latino, and 35.1% White) entering drug treatment indicated that internal motivation and external pressure significantly and positively predicted dramatic relief and that dramatic relief significantly predicted attitudes towards drug treatment: χ2=142.20, df=100, p<0.01; Robust Comparative Fit Index=0.97, Root Mean Squared Error of Approximation=0.03. These results indicate that when external pressure and internal motivation are high, dramatic relief is also likely to be high. When dramatic relief is high, attitudes towards drug treatment are likely to be positive. The findings indicate that interventions to get individuals into drug treatment should include processes that promote Dramatic Relief. Implications for addictions health services are discussed. PMID:18535908

Short-term Morphodynamics of an Eroding Salt Marsh Shoreline in the Delaware Estuary, USA

NASA Astrophysics Data System (ADS)

Fanta, D.; Quirk, T. E.

2017-12-01

Marsh edge morphology can change rapidly through erosional and depositional processes. Along seemingly similar stretches of marsh shoreline, erosion processes and rates can vary dramatically. In the Delaware Estuary, annual rates of edge erosion vary from a few centimeters to several meters across relatively short stretches of shoreline. Differences in erosion processes observed here include areas with and without vegetation growth seaward of the eroding marsh scarp. To better understand the factors that influence changes in marsh edge morphology, we examined wave energy, marsh scarp profile, and vegetation structure in relation to lateral erosion and accretion along two stretches of the Delaware Estuary for two years. Rates of erosion ranged from 0.01 to over 7 m/yr depending on shoreline exposure to waves and location on marsh scarp depth profile. Sediment deposition and accretion were up to an order of magnitude higher 15 cm from the marsh edge than 5 cm from the marsh edge, and were driven by storm events. In some areas, vegetation persisted seaward of eroding marshes where wave activity was dampened by a shallower bathymetric profile. Wave energy, distance from the edge and marsh elevation all contributed to vegetation structure, and therefore sedimentation and accretion dynamics. These results highlight the interactive nature of biophysical processes leading to lateral retreat or potential resilience of marsh edges.

Recent morphological changes of the Yellow River (Huanghe) submerged delta: Causes and environmental implications

NASA Astrophysics Data System (ADS)

Jiang, Chao; Pan, Shunqi; Chen, Shenliang

2017-09-01

The Yellow River (Huanghe) submerged delta (YRSD) has been under the threat of erosion and retreat during the Anthropocene due to dramatic climatic and anthropogenic changes in the Yellow River basin. The analysis of field data shows that over the period of 1977-2005, the changes in climate (decrease in precipitation and increase in air temperature) and human interventions (increase in water diversion projects) throughout the watershed have resulted in the sharp reductions of river flow and sediment discharges into the Bohai Sea. Consequently, over the decadal timescale, morphological evolution of the YRSD has gone through three stages: i.e. rapid accumulation (5.77 × 108 m3/year) in 1977-1985, moderate accumulation (3.80 × 108 m3/year) in 1986-1995 and slow accumulation (0.91 × 108 m3/year) in 1996-2005. Climatic change within the catchment characterized by the rapid increase of air temperature contributed significantly to the transitions from the rapid accumulation to the moderate accumulation, and to the subsequent slow accumulation. The decadal morphological changes of the YRSD also show peculiar deposition/erosion characteristics over the medium timescale under river input reduction. Within the three decades, the patterns of the main sedimentary body exhibit irregular ellipses with the long axis parallel to the - 5 or - 10 m isobaths and short axis perpendicular to the isobaths. The depocentres of the YRSD are located between the - 10 and - 15 m isobaths close to the respective river mouths, with a high vertical accretion rate of 1.20 m/year. The time series data of annual volumetric change of the YRSD and river sediment load from 1977 to 2005 further demonstrate significant linear positive relationships between deltaic geomorphic change and fluvial input over shorter timescales (annual and 3-year). The critical sediment discharges for maintaining the deposition/erosion equilibrium state of the YRSD over the annual and 3-year timescales are found to be 1.79 × 108 t/year and 1.29 × 108 t/year, respectively. The analysis from the latest hydrological data (2006-2015) suggests that over the decadal timescale, the evolution state of the YRSD currently has transitioned from constructive to destructive due to the weakened fluvial input. Moreover, there exists a close quantitative link between the progradation of the Yellow River subaerial delta (YRAD) and the YRSD over the five-year timescale, indicating that every 1 × 108 m3/year increase of the YRSD's yearly volumetric change will result in a 3.28 km2/year increase of the YRAD's yearly land-accretion area, and the YRAD will reach the extension/retreat balance state when yearly morphological change of the YRSD is at 0.73 × 108 m3/year.

Cartilaginous Epiphyses in Extant Archosaurs and Their Implications for Reconstructing Limb Function in Dinosaurs

PubMed Central

Holliday, Casey M.; Ridgely, Ryan C.; Sedlmayr, Jayc C.; Witmer, Lawrence M.

2010-01-01

Extinct archosaurs, including many non-avian dinosaurs, exhibit relatively simply shaped condylar regions in their appendicular bones, suggesting potentially large amounts of unpreserved epiphyseal (articular) cartilage. This “lost anatomy” is often underappreciated such that the ends of bones are typically considered to be the joint surfaces, potentially having a major impact on functional interpretation. Extant alligators and birds were used to establish an objective basis for inferences about cartilaginous articular structures in such extinct archosaur clades as non-avian dinosaurs. Limb elements of alligators, ostriches, and other birds were dissected, disarticulated, and defleshed. Lengths and condylar shapes of elements with intact epiphyses were measured. Limbs were subsequently completely skeletonized and the measurements repeated. Removal of cartilaginous condylar regions resulted in statistically significant changes in element length and condylar breadth. Moreover, there was marked loss of those cartilaginous structures responsible for joint architecture and congruence. Compared to alligators, birds showed less dramatic, but still significant changes. Condylar morphologies of dinosaur limb bones suggest that most non-coelurosaurian clades possessed large cartilaginous epiphyses that relied on the maintenance of vascular channels that are otherwise eliminated early in ontogeny in smaller-bodied tetrapods. A sensitivity analysis using cartilage correction factors (CCFs) obtained from extant taxa indicates that whereas the presence of cartilaginous epiphyses only moderately increases estimates of dinosaur height and speed, it has important implications for our ability to infer joint morphology, posture, and the complicated functional movements in the limbs of many extinct archosaurs. Evidence suggests that the sizes of sauropod epiphyseal cartilages surpassed those of alligators, which account for at least 10% of hindlimb length. These data suggest that large cartilaginous epiphyses were widely distributed among non-avian archosaurs and must be considered when making inferences about locomotor functional morphology in fossil taxa. PMID:20927347

Cartilaginous epiphyses in extant archosaurs and their implications for reconstructing limb function in dinosaurs.

PubMed

Holliday, Casey M; Ridgely, Ryan C; Sedlmayr, Jayc C; Witmer, Lawrence M

2010-09-30

Extinct archosaurs, including many non-avian dinosaurs, exhibit relatively simply shaped condylar regions in their appendicular bones, suggesting potentially large amounts of unpreserved epiphyseal (articular) cartilage. This "lost anatomy" is often underappreciated such that the ends of bones are typically considered to be the joint surfaces, potentially having a major impact on functional interpretation. Extant alligators and birds were used to establish an objective basis for inferences about cartilaginous articular structures in such extinct archosaur clades as non-avian dinosaurs. Limb elements of alligators, ostriches, and other birds were dissected, disarticulated, and defleshed. Lengths and condylar shapes of elements with intact epiphyses were measured. Limbs were subsequently completely skeletonized and the measurements repeated. Removal of cartilaginous condylar regions resulted in statistically significant changes in element length and condylar breadth. Moreover, there was marked loss of those cartilaginous structures responsible for joint architecture and congruence. Compared to alligators, birds showed less dramatic, but still significant changes. Condylar morphologies of dinosaur limb bones suggest that most non-coelurosaurian clades possessed large cartilaginous epiphyses that relied on the maintenance of vascular channels that are otherwise eliminated early in ontogeny in smaller-bodied tetrapods. A sensitivity analysis using cartilage correction factors (CCFs) obtained from extant taxa indicates that whereas the presence of cartilaginous epiphyses only moderately increases estimates of dinosaur height and speed, it has important implications for our ability to infer joint morphology, posture, and the complicated functional movements in the limbs of many extinct archosaurs. Evidence suggests that the sizes of sauropod epiphyseal cartilages surpassed those of alligators, which account for at least 10% of hindlimb length. These data suggest that large cartilaginous epiphyses were widely distributed among non-avian archosaurs and must be considered when making inferences about locomotor functional morphology in fossil taxa.

Morphological, cytological and metabolic consequences of autopolyploidization in Hylocereus (Cactaceae) species.

PubMed

Cohen, Hagai; Fait, Aaron; Tel-Zur, Noemi

2013-11-04

Genome doubling may have multi-level effects on the morphology, viability and physiology of polyploids compared to diploids. We studied the changes associated with autopolyploidization in two systems of somatic newly induced polyploids, diploid-autotetraploid and triploid-autohexaploid, belonging to the genus Hylocereus (Cactaceae). Stomata, fruits, seeds, embryos, and pollen were studied. Fruit pulp and seeds were subjected to metabolite profiling using established gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography (UPLC) Q-TOF-MS/MS (time of flight)-protocols. Autopolyploid lines produced lower numbers of tetrads, larger pollen grains with lower viability, larger stomata with lower density, and smaller fruits with lower seed numbers and decreased seed viability. The abundance of sugars was lower in the fruits and seeds of the two duplicated lines than in their donor lines, accompanied by increased contents of amino acids, tricarboxylic acid (TCA) cycle intermediates, organic acids and flavonoids. Betacyanins, the major fruit pigments in diploid and triploid donors, decreased following genome doubling. Both autopolyploid Hylocereus lines thus exhibited unfavorable changes, with the outcome being more dramatic in the autohexaploid than in the autotetraploid line. Induced autotetraploid and autohexaploid lines exhibited morphological and cytological characteristics that differed from those of their donor plants and that were accompanied by significant metabolic alterations. It is suggested that a developmental arrest occurs in the fruits of the autohexaploid line, since their pericarp shows a greater abundance of acids and of reduced sugars. We conclude that genome doubling does not necessarily confer a fitness advantage and that the extent of alterations induced by autopolyploidization depends on the genetic background of the donor genotype.

Morphological, cytological and metabolic consequences of autopolyploidization in Hylocereus (Cactaceae) species

PubMed Central

2013-01-01

Background Genome doubling may have multi-level effects on the morphology, viability and physiology of polyploids compared to diploids. We studied the changes associated with autopolyploidization in two systems of somatic newly induced polyploids, diploid-autotetraploid and triploid-autohexaploid, belonging to the genus Hylocereus (Cactaceae). Stomata, fruits, seeds, embryos, and pollen were studied. Fruit pulp and seeds were subjected to metabolite profiling using established gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography (UPLC) Q-TOF-MS/MS (time of flight)-protocols. Results Autopolyploid lines produced lower numbers of tetrads, larger pollen grains with lower viability, larger stomata with lower density, and smaller fruits with lower seed numbers and decreased seed viability. The abundance of sugars was lower in the fruits and seeds of the two duplicated lines than in their donor lines, accompanied by increased contents of amino acids, tricarboxylic acid (TCA) cycle intermediates, organic acids and flavonoids. Betacyanins, the major fruit pigments in diploid and triploid donors, decreased following genome doubling. Both autopolyploid Hylocereus lines thus exhibited unfavorable changes, with the outcome being more dramatic in the autohexaploid than in the autotetraploid line. Conclusion Induced autotetraploid and autohexaploid lines exhibited morphological and cytological characteristics that differed from those of their donor plants and that were accompanied by significant metabolic alterations. It is suggested that a developmental arrest occurs in the fruits of the autohexaploid line, since their pericarp shows a greater abundance of acids and of reduced sugars. We conclude that genome doubling does not necessarily confer a fitness advantage and that the extent of alterations induced by autopolyploidization depends on the genetic background of the donor genotype. PMID:24188386

Extracellular matrix protein in calcified endoskeleton: a potential additive for crystal growth and design

NASA Astrophysics Data System (ADS)

Azizur Rahman, M.; Fujimura, Hiroyuki; Shinjo, Ryuichi; Oomori, Tamotsu

2011-06-01

In this study, we demonstrate a key function of extracellular matrix proteins (ECMPs) on seed crystals, which are isolated from calcified endoskeletons of soft coral and contain only CaCO 3 without any living cells. This is the first report that an ECMP protein extracted from a marine organism could potentially influence in modifying the surface of a substrate for designing materials via crystallization. We previously studied with the ECMPs from a different type of soft coral ( Sinularia polydactyla) without introducing any seed crystals in the process , which showed different results. Thus, crystallization on the seed in the presence of ECMPs of present species is an important first step toward linking function to individual proteins from soft coral. For understanding this interesting phenomenon, in vitro crystallization was initiated in a supersaturated solution on seed particles of calcite (1 0 4) with and without ECMPs. No change in the crystal growth shape occurred without ECMPs present during the crystallization process. However, with ECMPs, the morphology and phase of the crystals in the crystallization process changed dramatically. Upon completion of crystallization with ECMPs, an attractive crystal morphology was found. Scanning electron microscopy (SEM) was utilized to observe the crystal morphologies on the seeds surface. The mineral phases of crystals nucleated by ECMPs on the seeds surface were examined by Raman spectroscopy. Although 50 mM Mg 2+ is influential in making aragonite in the crystallization process, the ECMPs significantly made calcite crystals even when 50 mM Mg 2+ was present in the process. Crystallization with the ECMP additive seems to be a technically attractive strategy to generate assembled micro crystals that could be used in crystals growth and design in the Pharmaceutical and biotechnology industries.

Genetic divergence between freshwater and marine morphs of alewife (Alosa pseudoharengus): a 'next-generation' sequencing analysis.

PubMed

Czesny, Sergiusz; Epifanio, John; Michalak, Pawel

2012-01-01

Alewife Alosa pseudoharengus, a small clupeid fish native to Atlantic Ocean, has recently (∼150 years ago) invaded the North American Great Lakes and despite challenges of freshwater environment its populations exploded and disrupted local food web structures. This range expansion has been accompanied by dramatic changes at all levels of organization. Growth rates, size at maturation, or fecundity are only a few of the most distinct morphological and life history traits that contrast the two alewife morphs. A question arises to what extent these rapidly evolving differences between marine and freshwater varieties result from regulatory (including phenotypic plasticity) or structural mutations. To gain insights into expression changes and sequence divergence between marine and freshwater alewives, we sequenced transcriptomes of individuals from Lake Michigan and Atlantic Ocean. Population specific single nucleotide polymorphisms were rare but interestingly occurred in sequences of genes that also tended to show large differences in expression. Our results show that the striking phenotypic divergence between anadromous and lake alewives can be attributed to massive regulatory modifications rather than coding changes.

Genetic Divergence between Freshwater and Marine Morphs of Alewife (Alosa pseudoharengus): A ‘Next-Generation’ Sequencing Analysis

PubMed Central

Czesny, Sergiusz; Epifanio, John; Michalak, Pawel

2012-01-01

Alewife Alosa pseudoharengus, a small clupeid fish native to Atlantic Ocean, has recently (∼150 years ago) invaded the North American Great Lakes and despite challenges of freshwater environment its populations exploded and disrupted local food web structures. This range expansion has been accompanied by dramatic changes at all levels of organization. Growth rates, size at maturation, or fecundity are only a few of the most distinct morphological and life history traits that contrast the two alewife morphs. A question arises to what extent these rapidly evolving differences between marine and freshwater varieties result from regulatory (including phenotypic plasticity) or structural mutations. To gain insights into expression changes and sequence divergence between marine and freshwater alewives, we sequenced transcriptomes of individuals from Lake Michigan and Atlantic Ocean. Population specific single nucleotide polymorphisms were rare but interestingly occurred in sequences of genes that also tended to show large differences in expression. Our results show that the striking phenotypic divergence between anadromous and lake alewives can be attributed to massive regulatory modifications rather than coding changes. PMID:22438868

Targeting SMN to Cajal bodies and nuclear gems during neuritogenesis

PubMed Central

Navascues, Joaquin; Berciano, Maria T.; Tucker, Karen E.

2006-01-01

Neurite outgrowth is a central feature of neuronal differentiation. PC12 cells are a good model system for studying the peripheral nervous system and the outgrowth of neurites. In addition to the dramatic changes observed in the cytoplasm, neuronal differentiation is also accompanied by striking changes in nuclear morphology. The large and sustained increase in nuclear transcription during neuronal differentiation requires synthesis of a large number of factors involved in pre-mRNA processing. We show that the number and composition of the nuclear subdomains called Cajal bodies and gems changes during the course of N-ras-induced neuritogenesis in the PC12-derived cell line UR61. The Cajal bodies found in undifferentiated cells are largely devoid of the survival of motor neurons (SMN) protein product. As cells shift to a differentiated state, SMN is not only globally upregulated, but is progressively recruited to Cajal bodies. Additional SMN foci (also known as Gemini bodies, gems) can also be detected. Using dual-immunogold labeling electron microscopy and mouse embryonic fibroblasts lacking the coilin protein, we show that gems clearly represent a distinct category of nuclear body. PMID:15164213

Molybdenum Carbamate Nanosheets as a New Class of Potential Phase Change Materials.

PubMed

Zhukovskyi, Maksym; Plashnitsa, Vladimir; Petchsang, Nattasamon; Ruth, Anthony; Bajpai, Anshumaan; Vietmeyer, Felix; Wang, Yuanxing; Brennan, Michael; Pang, Yunsong; Werellapatha, Kalpani; Bunker, Bruce; Chattopadhyay, Soma; Luo, Tengfei; Janko, Boldizsar; Fay, Patrick; Kuno, Masaru

2017-06-14

We report for the first time the synthesis of large, free-standing, Mo 2 O 2 (μ-S) 2 (Et 2 dtc) 2 (MoDTC) nanosheets (NSs), which exhibit an electron-beam induced crystalline-to-amorphous phase transition. Both electron beam ionization and femtosecond (fs) optical excitation induce the phase transition, which is size-, morphology-, and composition-preserving. Resulting NSs are the largest, free-standing regularly shaped two-dimensional amorphous nanostructures made to date. More importantly, amorphization is accompanied by dramatic changes to the NS electrical and optical response wherein resulting amorphous species exhibit room-temperature conductivities 5 orders of magnitude larger than those of their crystalline counterparts. This enhancement likely stems from the amorphization-induced formation of sulfur vacancy-related defects and is supported by temperature-dependent transport measurements, which reveal efficient variable range hopping. MoDTC NSs represent one instance of a broader class of transition metal carbamates likely having applications because of their intriguing electrical properties as well as demonstrated ability to toggle metal oxidation states.

Effects of boundaries and geometry on the spatial distribution of action potential duration in cardiac tissue

PubMed Central

Cherry, Elizabeth M.; Fenton, Flavio H.

2011-01-01

Increased dispersion of action potential duration across cardiac tissue has long been considered an important substrate for the development of most electrical arrhythmias. Although this dispersion has been studied previously by characterizing the static intrinsic gradients in cellular electrophysiology and dynamical gradients generated by fast pacing, few studies have concentrated on dispersions generated solely by structural effects. Here we show how boundaries and geometry can produce spatially dependent changes in action potential duration (APD) in homogeneous and isotropic tissue, where all the cells have the same APD in the absence of diffusion. Electrotonic currents due to coupling within the tissue and at the tissue boundaries can generate dispersion, and the profile of this dispersion can change dramatically depending on tissue size and shape, action potential morphology, tissue dimensionality, and stimulus frequency and location. The dispersion generated by pure geometrical effects can be on the order of tens of milliseconds, enough under certain conditions to produce conduction blocks and initiate reentrant waves. PMID:21762703

Acute and chronic gregarisation are associated with distinct DNA methylation fingerprints in desert locusts.

PubMed

Mallon, Eamonn B; Amarasinghe, Harindra E; Ott, Swidbert R

2016-10-18

Desert locusts (Schistocerca gregaria) show a dramatic form of socially induced phenotypic plasticity known as phase polyphenism. In the absence of conspecifics, locusts occur in a shy and cryptic solitarious phase. Crowding with conspecifics drives a behavioural transformation towards gregariousness that occurs within hours and is followed by changes in physiology, colouration and morphology, resulting in the full gregarious phase syndrome. We analysed methylation-sensitive amplified fragment length polymorphisms (MS-AFLP) to compare the effect of acute and chronic crowding on DNA methylation in the central nervous system. We find that crowd-reared and solitary-reared locusts show markedly different neural MS-AFLP fingerprints. However, crowding for a day resulted in neural MS-AFLP fingerprints that were clearly distinct from both crowd-reared and uncrowded solitary-reared locusts. Our results indicate that changes in DNA methylation associated with behavioural gregarisation proceed through intermediate states that are not simply partial realisations of the endpoint states.

The role of collapsing and cone rafting on eruption style changes and final cone morphology: Los Morados scoria cone, Mendoza, Argentina

NASA Astrophysics Data System (ADS)

Németh, Karoly; Risso, Corina; Nullo, Francisco; Kereszturi, Gabor

2011-06-01

Payún Matru Volcanic Field is a Quaternary monogenetic volcanic field that hosts scoria cones with perfect to breached morphologies. Los Morados complex is a group of at least four closely spaced scoria cones (Los Morados main cone and the older Cones A, B, and C). Los Morados main cone was formed by a long lived eruption of months to years. After an initial Hawaiian-style stage, the eruption changed to a normal Strombolian, conebuilding style, forming a cone over 150 metres high on a northward dipping (˜4°) surface. An initial cone gradually grew until a lava flow breached the cone's base and rafted an estimated 10% of the total volume. A sudden sector collapse initiated a dramatic decompression in the upper part of the feeding conduit and triggered violent a Strombolian style eruptive stage. Subsequently, the eruption became more stable, and changed to a regular Strombolian style that partially rebuilt the cone. A likely increase in magma flux coupled with the gradual growth of a new cone caused another lava flow outbreak at the structurally weakened earlier breach site. For a second time, the unstable flank of the cone was rafted, triggering a second violent Strombolian eruptive stage which was followed by a Hawaiian style lava fountain stage. The lava fountaining was accompanied by a steady outpour of voluminous lava emission accompanied by constant rafting of the cone flank, preventing the healing of the cone. Santa Maria is another scoria cone built on a nearly flat pre-eruption surface. Despite this it went through similar stages as Los Morados main cone, but probably not in as dramatic a manner as Los Morados. In contrast to these examples of large breached cones, volumetrically smaller cones, associated to less extensive lava flows, were able to heal raft/collapse events, due to the smaller magma output and flux rates. Our evidence shows that scoria cone growth is a complex process, and is a consequence of the magma internal parameters (e.g. volatile content, magma flux, recharge, output volume) and external conditions such as inclination of the pre-eruptive surface where they grew and thus gravitational instability.

Astronaut to Zoologist: Changing the Dramatic Play Area!

ERIC Educational Resources Information Center

Brouette, Scott J.

Changing the dramatic play area in a child care setting promotes creativity and gives children the chance to experience a place they may never experience in real life. Whenever possible, the children should be involved in the process of changing the area, by moving furniture and exchanging props, as well as brainstorming ideas for changes. The…

XRF map identification problems based on a PDE electrodeposition model

NASA Astrophysics Data System (ADS)

Sgura, Ivonne; Bozzini, Benedetto

2017-04-01

In this paper we focus on the following map identification problem (MIP): given a morphochemical reaction-diffusion (RD) PDE system modeling an electrodepostion process, we look for a time t *, belonging to the transient dynamics and a set of parameters \\mathbf{p} , such that the PDE solution, for the morphology h≤ft(x,y,{{t}\\ast};\\mathbf{p}\\right) and for the chemistry θ ≤ft(x,y,{{t}\\ast};\\mathbf{p}\\right) approximates a given experimental map M *. Towards this aim, we introduce a numerical algorithm using singular value decomposition (SVD) and Frobenius norm to give a measure of error distance between experimental maps for h and θ and simulated solutions of the RD-PDE system on a fixed time integration interval. The technique proposed allows quantitative use of microspectroscopy images, such as XRF maps. Specifically, in this work we have modelled the morphology and manganese distributions of nanostructured components of innovative batteries and we have followed their changes resulting from ageing under operating conditions. The availability of quantitative information on space-time evolution of active materials in terms of model parameters will allow dramatic improvements in knowledge-based optimization of battery fabrication and operation.

Sonication-Induced Modification of Carbon Nanotubes: Effect on the Rheological and Thermo-Oxidative Behaviour of Polymer-Based Nanocomposites.

PubMed

Arrigo, Rossella; Teresi, Rosalia; Gambarotti, Cristian; Parisi, Filippo; Lazzara, Giuseppe; Dintcheva, Nadka Tzankova

2018-03-05

The aim of this work is the investigation of the effect of ultrasound treatment on the structural characteristics of carbon nanotubes (CNTs) and the consequent influence that the shortening induced by sonication exerts on the morphology, rheological behaviour and thermo-oxidative resistance of ultra-high molecular weight polyethylene (UHMWPE)-based nanocomposites. First, CNTs have been subjected to sonication for different time intervals and the performed spectroscopic and morphological analyses reveal that a dramatic decrease of the CNT's original length occurs with increased sonication time. The reduction of the initial length of CNTs strongly affects the nanocomposite rheological behaviour, which progressively changes from solid-like to liquid-like as the CNT sonication time increases. The study of the thermo-oxidative behaviour of the investigated nanocomposites reveals that the CNT sonication has a detrimental effect on the thermo-oxidative stability of nanocomposites, especially for long exposure times. The worsening of the thermo-oxidative resistance of sonicated CNT-containing nanocomposites could be attributed to the lower thermal conductivity of low-aspect-ratio CNTs, which causes the increase of the local temperature at the polymer/nanofillers interphase, with the consequent acceleration of the degradative phenomena.

Cationic PAMAM dendrimers disrupt key platelet functions

PubMed Central

Jones, Clinton F.; Campbell, Robert A.; Franks, Zechariah; Gibson, Christopher C.; Thiagarajan, Giridhar; Vieira-de-Abreu, Adriana; Sukavaneshvar, Sivaprasad; Mohammad, S. Fazal; Li, Dean Y.; Ghandehari, Hamidreza; Weyrich, Andrew S.; Brooks, Benjamin D.; Grainger, David W.

2012-01-01

Poly(amidoamine) (PAMAM) dendrimers have been proposed for a variety of biomedical applications and are increasingly studied as model nanomaterials for such use. The dendritic structure features both modular synthetic control of molecular size and shape and presentation of multiple equivalent terminal groups. These properties make PAMAM dendrimers highly functionalizable, versatile single-molecule nanoparticles with a high degree of consistency and low polydispersity. Recent nanotoxicological studies showed that intravenous administration of amine-terminated PAMAM dendrimers to mice was lethal, causing a disseminated intravascular coagulation-like condition. To elucidate the mechanisms underlying this coagulopathy, in vitro assessments of platelet functions in contact with PAMAM dendrimers were undertaken. This study demonstrates that cationic G7 PAMAM dendrimers activate platelets and dramatically alter their morphology. These changes to platelet morphology and activation state substantially altered platelet function, including increased aggregation and adherence to surfaces. Surprisingly, dendrimer exposure also attenuated platelet-dependent thrombin generation, indicating that not all platelet functions remained intact. These findings provide additional insight into PAMAM dendrimer effects on blood components and underscore the necessity for further research on the effects and mechanisms of PAMAM-specific and general nanoparticle toxicity in blood. PMID:22497592

Gold nanoparticles deposited on glass: physicochemical characterization and cytocompatibility

PubMed Central

2013-01-01

Properties of gold films sputtered under different conditions onto borosilicate glass substrate were studied. Mean thickness of sputtered gold film was measured by gravimetry, and film contact angle was determined by goniometry. Surface morphology was examined by atomic force microscopy, and electrical sheet resistance was determined by two-point technique. The samples were seeded with rat vascular smooth muscle cells, and their adhesion and proliferation were studied. Gold depositions lead to dramatical changes in the surface morphology and roughness in comparison to pristine substrate. For sputtered gold structures, the rapid decline of the sheet resistance appears on structures deposited for the times above 100 s. The thickness of deposited gold nanoparticles/layer is an increasing function of sputtering time and current. AFM images prove the creation of separated gold islands in the initial deposition phase and a continuous gold coverage for longer deposition times. Gold deposition has a positive effect on the proliferation of vascular smooth muscle cells. Largest number of cells was observed on sample sputtered with gold for 20 s and at the discharge current of 40 mA. This sample exhibits lowest contact angle, low relative roughness, and only mild increase of electrical conductivity. PMID:23705782

Sonication-Induced Modification of Carbon Nanotubes: Effect on the Rheological and Thermo-Oxidative Behaviour of Polymer-Based Nanocomposites

PubMed Central

Teresi, Rosalia; Gambarotti, Cristian; Dintcheva, Nadka Tzankova

2018-01-01

The aim of this work is the investigation of the effect of ultrasound treatment on the structural characteristics of carbon nanotubes (CNTs) and the consequent influence that the shortening induced by sonication exerts on the morphology, rheological behaviour and thermo-oxidative resistance of ultra-high molecular weight polyethylene (UHMWPE)-based nanocomposites. First, CNTs have been subjected to sonication for different time intervals and the performed spectroscopic and morphological analyses reveal that a dramatic decrease of the CNT’s original length occurs with increased sonication time. The reduction of the initial length of CNTs strongly affects the nanocomposite rheological behaviour, which progressively changes from solid-like to liquid-like as the CNT sonication time increases. The study of the thermo-oxidative behaviour of the investigated nanocomposites reveals that the CNT sonication has a detrimental effect on the thermo-oxidative stability of nanocomposites, especially for long exposure times. The worsening of the thermo-oxidative resistance of sonicated CNT-containing nanocomposites could be attributed to the lower thermal conductivity of low-aspect-ratio CNTs, which causes the increase of the local temperature at the polymer/nanofillers interphase, with the consequent acceleration of the degradative phenomena. PMID:29510595

Historical Sediment Sources and Delivery on the Lower Mississippi River

NASA Astrophysics Data System (ADS)

Dahl, T. A.; Biedenharn, D. S.; Little, C. D.

2015-12-01

The development of the Lower Mississippi River (LMR) and its floodplain for navigation and flood control has been ongoing since the 18th century, with the most concerted efforts occurring as a result of the Flood Control Act (FCA) of 1928 following the Great Flood of 1927. The Mississippi River and Tributaries (MR&T) Project that was spawned from the FCA of 1928 has produced a massive, comprehensive system for flood control and channel stabilization that includes levees, channel improvements, and floodways, as well as tributary reservoirs and other basin improvements. Additionally, the development of the river for safe and dependable navigation has generated a substantial engineering effort involving river training structures, meander cutoffs, and dredging. The historical, and present-day morphology of the LMR reflects an integration of all these engineering interventions (and the process-responses they have triggered in the fluvial system), combined with natural drivers of channel change and evolution, including floods and droughts, hurricanes, neotectonic activity, geologic outcrops, climate change, and relative sea-level rise. In response to the complex requirements in navigation, flood risk reduction, and environmental restoration, all with multiple stakeholders, the U.S. Army Corps of Engineers created the Mississippi River Geomorphology & Potamology (MRG&P) Program. The goals of the MRG&P are to advance the knowledge of the geomorphology of the LMR and to transfer this technology to improve and sustain long-term management of the system. The results presented herein come from several MRG&P studies. The historical river morphology, and particularly the sources and delivery of sediments have changed dramatically over the past two centuries. In this presentation, the changes in sediment sources, and the manner in which this sediment is delivered through the channel system from the early 1800s to present-day is described.

Geomorphic Mapping and Paleoterrain Generation for use in Modeling Holocene (8,000 1,500 yr) Agropastoral Landuse and Landscape Interactions in Southeast Spain

NASA Astrophysics Data System (ADS)

Arrowsmith, J. R.; Dimaggio, E. N.; Barton, C. M.; Sarjoughian, H. S.; Fall, P.; Falconer, S. E.; Ullah, I. I.

2006-12-01

Dramatic changes in land use were associated with the rise of agriculture in the mid Holocene. Both the surface properties and the drainage networks were changed. Along with the direct modifications to surface properties (vegetation change, sediment liberation, and compaction) and drainage network alteration (terracing, canals), up and downstream responses in the watersheds communicated these changes throughout the landscape. The magnitude, rate, and feedbacks with the growing human populations are critical questions in our effort to assess human-landscape interactions. Our interdisciplinary team has focused on two field sites around the Mediterranean for model development and testing. We are combining high resolution process- based models of landscape change implemented within the GRASS GIS with agent based models of agropastoral behavior and driven by high resolution climate and vegetation models. In the Spanish field area (Penaguila Valley, 38.41 N 0.23 W), we have produced detailed (1:10,000) geomorphic maps which we combine with high resolution Digital Elevation Models (DEMs) on which we can run the surface process models to assess the portions of the landscape that are most sensitive to the postulated agropastoral landuse changes. To support this modeling we have produced the 1 m DEMs from softcopy photogrammetry. This DEM has greatly improved our overall spatial resolution to permit more accurate terrace correlations and improved quantitative assessment of morphologic processes (e.g. channel erosion, slope stability). In stereo, we have mapped overall landscape morphology that emphasizes areas of active erosion and alluvial terrace surfaces. Alluvial terraces are crucial to this research because they record periods of past stable topography and those of mid Holocene age were settled and farmed. We have correlated mapped terraces across the landscape using elevation and morphological distinctions. Using ArcGIS, we interpolated surfaces across equivalent terraces using triangulated irregular networks (TINs) allowing reconstruction of multiple regional landscapes to establish a chronosequence of absolute landscape change. This mapping and reconstruction will be field checked and numerical age constraints applied. Interestingly, our tentative age assessment of the lowest broad surface indicates that it was occupied about 5 ka, and now has been incised by 20 m. Archeological sites have been cut by the incision. This change from a broad low relief alluvial surface to one cut by narrow channels may have been an important change for the local populations and caused them to change their behaviors, even though it may have been initially triggered by distributed landscape change in the watershed, due to agropastoral activities.

Effects of the Antioxidant α-Lipoic Acid on Human Umbilical Vein Endothelial Cells Infected with Rickettsia rickettsii

PubMed Central

Eremeeva, Marina E.; Silverman, David J.

1998-01-01

Rickettsia rickettsii infection of endothelial cells is manifested in very distinctive changes in cell morphology, consisting of extensive dilatation of the membranes of the endoplasmic reticulum and outer nuclear envelope and blebbing of the plasma membrane, as seen by transmission electron microscopy (D. J. Silverman, Infect. Immun. 44:545–553, 1984). These changes in cellular architecture are thought to be due to oxidant-mediated cell injury, since their occurrence correlates with dramatic alterations in cellular metabolism, particularly with regard to antioxidant systems. In this study, it was shown that R. rickettsii infection of human umbilical vein endothelial cells resulted in a significant depletion of intracellular reduced glutathione (thiol) content at 72 and 96 h and decreased glutathione peroxidase activity at 72 h postinfection. Infected cells displayed a dramatic increase in the concentration of intracellular peroxides by 72 h. Supplementation of the cell culture medium with 100, 200, or 500 μM α-lipoic acid, a metabolic antioxidant, after inoculation with R. rickettsii restored the intracellular levels of thiols and glutathione peroxidase and reduced the intracellular peroxide levels in infected cells. These effects were dose dependent. Treated infected monolayers maintained better viability at 96 h after inoculation with R. rickettsii than did untreated infected cells. Moreover, supplementation of the cell culture medium with 100 μM α-lipoic acid for 72 h after infection prevented the occurrence of morphological changes in the infected cells. The presence of 100 or 200 μM α-lipoic acid did not influence rickettsial growth in endothelial cells, nor did it affect the ability of R. rickettsii to form lytic plaques in Vero cells. Treatment with 500 μM α-lipoic acid decreased by 50% both the number and size of lytic plaques in Vero cells, and it also decreased the recovery of viable rickettsiae from endothelial cells. However, under all treatment conditions, a significant number of rickettsiae could be detected microscopically. Furthermore, the rickettsiae apparently retained their capacity for intracellular movement, since they possessed long polymerized actin tails after 72 and 96 h of treatment regardless of the concentration of α-lipoic acid used. Since α-lipoic acid does not seem to exhibit direct antirickettsial activity except with long-term exposure at very high concentrations, the mechanism of its protective activity for endothelial cells infected with rickettsiae may involve complex changes in cellular metabolism that only indirectly affect rickettsiae. PMID:9573120

Examining the Cross-Roads: School Segregation in Indiana

ERIC Educational Resources Information Center

Moon, Jodi S.; Krull, Lauren

2017-01-01

Demographics in the U.S. have changed dramatically over the last three decades. Indiana's demographics are changing, too--albeit less dramatically. To explore how demographic shifts are changing the composition of Indiana's schools, the Center for Evaluation and Education Policy (CEEP) uses Common Core of Data (CCD) school enrollment data from the…

Fulcrum of Change: Leveraging 50 States to Turn around 5000 Schools

ERIC Educational Resources Information Center

Rhim, Lauren Morando; Redding, Sam

2011-01-01

In 2010, unprecedented levels of resources began to flow through state education agencies (SEAs) to support dramatic change in persistently low-performing schools under the expanded federal School Improvement Grant (SIG) program. The challenge for states is to leverage the federal investment to drive dramatic and sustainable change efforts in…

Plasmonic resonances in ordered and disordered aluminum nanocavities arrays.

NASA Astrophysics Data System (ADS)

Campuzano, R. G.; Mendoza, D.

2017-01-01

Nanocavities arrays were synthesized by electrochemical anodization of aluminum using oxalic and phosphoric acids as electrolytes. The morphology and topography of these structures were evaluated by SEM and AFM. Plasmonic properties of Al cavities arrays with different ordering and dimensions were analysed based on specular reflectivity. Al cavities arrays fabricated with phosphoric acid dramatically reduced the optical reflectivity as compared with unstructured Al. At the same time pronounced reflectivity dips were detectable in the 300nm-400nm range, which were ascribed to (0,1) plasmonic mode, and also a colored appearance in the samples is noticeably depending on the observation angle. These changes are not observed in samples made with oxalic acid and this fact was explained, based on a theoretical model, in terms that the surface plasmons are excited far in the UV range.

Enhancement of valve metal osteoconductivity by one-step hydrothermal treatment.

PubMed

Zuldesmi, Mansjur; Waki, Atsushi; Kuroda, Kensuke; Okido, Masazumi

2014-09-01

In this study, we produced super-hydrophilic surfaces of valve metals (Ti, Nb, Ta and Zr) by one-step hydrothermal treatment. Their surface characteristics and osteoconductivity using an in vivo test were then assessed. These data were compared with that of as-polished, as-anodized and both anodized+hydrothermally treated samples. Changes in surface chemistry, surface morphology and structure were investigated by X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray diffractometry. The results revealed that the water contact angles of valve metals were decreased by hydrothermal treatment and continued to reduce dramatically until lower than 10° after being immersed in phosphate buffered solution. By producing super-hydrophilic surfaces, the osteoconductivity of these hydrothermally treated valve metals was enhanced by up to 55%. Copyright © 2014 Elsevier B.V. All rights reserved.

Responsive hybrid inorganic-organic system derived from lanthanide luminescence

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

Zhou, Zhan; Zheng, Yuhui, E-mail: yhzheng78@scnu.edu.cn; Jiang, Lasheng

2016-05-15

Highlights: • A novel covalent hybrid material was used to detect hemoglobin. • All the recognition experiments were performed in buffer solution. • Porous nano-structures was extensively studied for the recognition. - Abstract: Terbium ions were incorporated into new organic-inorganic matrices to achieve intense green emissions. Hemoglobin (HB) interactions lead to dramatic changes in the luminescence emission intensities. Infrared spectra, morphological studies and photoluminescence give information for the speciation and process of hemoglobin additions. The porous material has a large specific surface area of 351 cm{sup 2}/g and the detection limit for HB (0.7 μM) was much lower than itsmore » physical doped material (8 μM). This promising hybrid material will lead to the design of versatile optical probes that are efficiently responding to the external targets.« less

Ancient DNA Provides New Insights into the Evolutionary History of New Zealand's Extinct Giant Eagle

PubMed Central

Szulkin, Marta; Lerner, Heather R. L; Barnes, Ian; Shapiro, Beth; Cooper, Alan; Holdaway, Richard N

2005-01-01

Prior to human settlement 700 years ago New Zealand had no terrestrial mammals—apart from three species of bats—instead, approximately 250 avian species dominated the ecosystem. At the top of the food chain was the extinct Haast's eagle, Harpagornis moorei. H. moorei (10–15 kg; 2–3 m wingspan) was 30%–40% heavier than the largest extant eagle (the harpy eagle, Harpia harpyja), and hunted moa up to 15 times its weight. In a dramatic example of morphological plasticity and rapid size increase, we show that the H. moorei was very closely related to one of the world's smallest extant eagles, which is one-tenth its mass. This spectacular evolutionary change illustrates the potential speed of size alteration within lineages of vertebrates, especially in island ecosystems. PMID:15660162

Sexual dimorphism of sonic apparatus and extreme intersexual variation of sounds in Ophidion rochei (Ophidiidae): first evidence of a tight relationship between morphology and sound characteristics in Ophidiidae

PubMed Central

2012-01-01

Background Many Ophidiidae are active in dark environments and display complex sonic apparatus morphologies. However, sound recordings are scarce and little is known about acoustic communication in this family. This paper focuses on Ophidion rochei which is known to display an important sexual dimorphism in swimbladder and anterior skeleton. The aims of this study were to compare the sound producing morphology, and the resulting sounds in juveniles, females and males of O. rochei. Results Males, females, and juveniles possessed different morphotypes. Females and juveniles contrasted with males because they possessed dramatic differences in morphology of their sonic muscles, swimbladder, supraoccipital crest, and first vertebrae and associated ribs. Further, they lacked the ‘rocker bone’ typically found in males. Sounds from each morphotype were highly divergent. Males generally produced non harmonic, multiple-pulsed sounds that lasted for several seconds (3.5 ± 1.3 s) with a pulse period of ca. 100 ms. Juvenile and female sounds were recorded for the first time in ophidiids. Female sounds were harmonic, had shorter pulse period (±3.7 ms), and never exceeded a few dozen milliseconds (18 ± 11 ms). Moreover, unlike male sounds, female sounds did not have alternating long and short pulse periods. Juvenile sounds were weaker but appear to be similar to female sounds. Conclusions Although it is not possible to distinguish externally male from female in O. rochei, they show a sonic apparatus and sounds that are dramatically different. This difference is likely due to their nocturnal habits that may have favored the evolution of internal secondary sexual characters that help to distinguish males from females and that could facilitate mate choice by females. Moreover, the comparison of different morphotypes in this study shows that these morphological differences result from a peramorphosis that takes place during the development of the gonads. PMID:23217241

Dramatic action: A theater-based paradigm for analyzing human interactions

PubMed Central

Raindel, Noa; Alon, Uri

2018-01-01

Existing approaches to describe social interactions consider emotional states or use ad-hoc descriptors for microanalysis of interactions. Such descriptors are different in each context thereby limiting comparisons, and can also mix facets of meaning such as emotional states, short term tactics and long-term goals. To develop a systematic set of concepts for second-by-second social interactions, we suggest a complementary approach based on practices employed in theater. Theater uses the concept of dramatic action, the effort that one makes to change the psychological state of another. Unlike states (e.g. emotions), dramatic actions aim to change states; unlike long-term goals or motivations, dramatic actions can last seconds. We defined a set of 22 basic dramatic action verbs using a lexical approach, such as ‘to threaten’–the effort to incite fear, and ‘to encourage’–the effort to inspire hope or confidence. We developed a set of visual cartoon stimuli for these basic dramatic actions, and find that people can reliably and reproducibly assign dramatic action verbs to these stimuli. We show that each dramatic action can be carried out with different emotions, indicating that the two constructs are distinct. We characterized a principal valence axis of dramatic actions. Finally, we re-analyzed three widely-used interaction coding systems in terms of dramatic actions, to suggest that dramatic actions might serve as a common vocabulary across research contexts. This study thus operationalizes and tests dramatic action as a potentially useful concept for research on social interaction, and in particular on influence tactics. PMID:29518101

The pivotal role of aristaless in development and evolution of diverse antennal morphologies in moths and butterflies.

PubMed

Ando, Toshiya; Fujiwara, Haruhiko; Kojima, Tetsuya

2018-01-25

Antennae are multi-segmented appendages and main odor-sensing organs in insects. In Lepidoptera (moths and butterflies), antennal morphologies have diversified according to their ecological requirements. While diurnal butterflies have simple, rod-shaped antennae, nocturnal moths have antennae with protrusions or lateral branches on each antennal segment for high-sensitive pheromone detection. A previous study on the Bombyx mori (silk moth) antenna, forming two lateral branches per segment, during metamorphosis has revealed the dramatic change in expression of antennal patterning genes to segmentally reiterated, branch-associated pattern and abundant proliferation of cells contributing almost all the dorsal half of the lateral branch. Thus, localized cell proliferation possibly controlled by the branch-associated expression of antennal patterning genes is implicated in lateral branch formation. Yet, actual gene function in lateral branch formation in Bombyx mori and evolutionary mechanism of various antennal morphologies in Lepidoptera remain elusive. We investigated the function of several genes and signaling specifically in lateral branch formation in Bombyx mori by the electroporation-mediated incorporation of siRNAs or morpholino oligomers. Knock down of aristaless, a homeobox gene expressed specifically in the region of abundant cell proliferation within each antennal segment, during metamorphosis resulted in missing or substantial shortening of lateral branches, indicating its importance for lateral branch formation. aristaless expression during metamorphosis was lost by knock down of Distal-less and WNT signaling but derepressed by knock down of Notch signaling, suggesting the strict determination of the aristaless expression domain within each antennal segment by the combinatorial action of them. In addition, analyses of pupal aristaless expression in antennae with various morphologies of several lepidopteran species revealed that the aristaless expression pattern has a striking correlation with antennal shapes, whereas the segmentally reiterated expression pattern was observed irrespective of antennal morphologies. Our results presented here indicate the significance of aristaless function in lateral branch formation in B. mori and imply that the diversification in the aristaless expression pattern within each antennal segment during metamorphosis is one of the significant determinants of antennal morphologies. According to these findings, we propose a mechanism underlying development and evolution of lepidopteran antennae with various morphologies.

Morphology-preserving chemical conversion of bioorganic and inorganic templates

NASA Astrophysics Data System (ADS)

Vernon, Jonathan Paul

The generation of nanostructured assemblies with complex (three-dimensional, 3D) self-assembled morphologies and with complex (multicomponent) tailorable inorganic compositions is of considerable technological and scientific interest. This dissertation demonstrates self-assembled 3D organic templates of biogenic origin can be converted into replicas comprised of numerous other functional nanocrystalline inorganic materials. Nature provides a spectacular variety of biologically-assembled 3D organic structures with intricate, hierarchical (macro-to-micro-to-nanoscale) morphologies. Such processing on readily-available structurally complex templates provides a framework for chemical conversion of synthetic organic templates and, potentially, production of organic/inorganic composites. Four specific research thrusts are detailed in this document. First, chemical conversion of a nanostructured bioorganic template into a multicomponent oxide compound (tetragonal BaTiO3) via SSG coating and subsequent morphology-preserving microwave hydrothermal processing is demonstrated. Second, morphology-preserving chemical conversion of bioorganic templates into hierarchical photoluminescent microparticles is demonstrated to reveal both the dramatic change in properties such processing can provide, and the potential utility of chemically transformed templates in anti-counterfeiting / authentication applications. Third, determination of the reaction mechanism(s) for morphology-preserving microwave hydrothermal conversion of TiO2 to BaTiO3, through Au inert markers on single crystal rutile titania, is detailed. Finally, utilization of constructive coating techniques (SSG) and moderate temperature (< 500°C) heat treatments to modify and replicate structural color is coupled with deconstructive focused ion beam microsurgery to prepare samples for microscale structure interrogation. Specifically, the effects of coating thickness and composition on reflection spectra of structurally colored templates are examined. Also, the effects of the replacement of natural material with higher index of refraction inorganic materials on optical properties are discussed. The three processing research thrusts constituting chapters 1, 2 and 4 take advantage of moderate temperature processing to ensure nanocrystalline materials, either for shape preservation or to prevent scattering in optical applications. The research thrust detailed in chapter 3 examines hydrothermal conversion of TiO2 to BaTiO3, not only to identify the reaction mechanism(s) involved in hydrothermal conversion under morphology-preserving conditions, but also to introduce inert marker experiments to the field of microwave hydrothermal processing.

In vivo administration of fluorescent dextrans for the specific and sensitive localization of brain vascular pericytes and their characterization in normal and neurotoxin exposed brains.

PubMed

Sarkar, Sumit; Schmued, Larry

2012-06-01

We have aimed to develop novel histochemical markers for the labeling of brain pericytes and characterize their morphology in the normal and the excitotoxin-exposed brain, as this class of cells has received little attention until recently. Pericyte labeling was accomplished by the intracerebroventricular injection of certain fluorescent dextran conjugates, such as Fluoro-Gold-dextran, FR-dextran, FITC-dextran and Fluoro-Turquoise (FT)-dextran. 1-7 days after the tracer injection, extensive labeling of vascular pericytes was seen throughout the entire brain. These cells were found distal to the endothelial cells and exhibited large dye containing vacuoles. The morphology of the pericytes was somewhat variable, exhibiting round or amoeboid shapes within larger intracellular vesicles, while those wrapping around capillaries exhibited a more elongated appearance with finger-like projections. The use of FG-dextran resulted in bluish yellow fluorescently labeled pericytes, while FR-dextran resulted in red fluorescent labeled pericytes, FITC-dextran exhibited green fluorescent pericytes and FT-dextran showed fluorescent blue pericytes in the brain. We have used these tracers to study possible changes in morphology and pericyte number following kainic acid insult, observing that the number of pericytes in the injured or lesioned areas of the brain is dramatically reduced compared to the non-injured areas. These novel fluorochromes should be of use for studies involving the detection and localization of pericytes in both normal and pathological brain tissues. Published by Elsevier B.V.

DMPS reverts morphologic and mitochondrial damage in OK cells exposed to toxic concentrations of HgCl2.

PubMed

Carranza-Rosales, Pilar; Guzmán-Delgado, Nancy E; Cruz-Vega, Delia E; Balderas-Rentería, Isaías; Gandolfi, A Jay

2007-05-01

Mercuric chloride (HgCl(2)) is a highly toxic compound, which can cause nephrotoxic damage. In the present study effects of HgCl(2) on mitochondria integrity and energy metabolism, as well as antidotal effects of 2,3-dimercaptopropane-1-sulfonate (DMPS) were investigated in the opossum kidney derived cell line (OK). OK cell monolayers were incubated during 0, 1, 3, 6, and 9 h in serum-free culture medium containing 15 microM HgCl(2), either in the absence or in the presence of 60 microM DMPS in a 1:4 ratio. Intracellular ATP content, MTT reduction, and HSP70/HSP90 induction were studied; confocal, transmission electron microscopy, and light microscopy studies were also performed. For confocal analysis, a mitochondrial selective probe (MitoTracker Red CMXH2Ros) was used. Antioxidant activity of DMPS was also studied by the scavenging of the free radical 2, 2-diphenyl-1-picrylhydrazyl (DPPH) technique. A decrease of ATP content, an impaired ability to reduce tetrazolium, and dramatic changes on cellular and mitochondrial morphology, and energetic levels were found after either 6 or 9 h of HgCl(2) exposure. Increased expression of HSP90 and HSP70 were also seen. When OK cells were co-incubated with HgCl(2) and DMPS, cellular morphology, viability, intracellular ATP, and mitochondrial membrane potential were partially restored; a protective effect on mitochondrial morphology was also seen. DMPS also showed potent antioxidant activity in vitro. Mitochondrial protection could be the cellular mechanism mediated by DMPS in OK cells exposed to a toxic concentration of HgCl(2).

Subtle effect of Xenos vesparum (Xenidae, Strepsiptera) on the reproductive apparatus of its male host: Parasite or parasitoid?

PubMed

Beani, L; Marchini, D; Cappa, F; Petrocelli, I; Gottardo, M; Manfredini, F; Giusti, F; Dallai, R

2017-08-01

Parasitic castration is an adaptive strategy where parasites usurp the hosts' reproductive physiology to complete their life cycle. The alterations in the host traits vary in their magnitude, from subtle changes in the host morpho-physiology and behaviour to the production of complex aberrant phenotypes, which often depend on the host gender. The strepsipteran macroparasite Xenos vesparum induces dramatic behavioural and physiological changes in its female host, the paper wasp Polistes dominula, while its effect on the male phenotype is largely unknown. In this study we investigated how a single X. vesparum parasite influences the functional morphology of P. dominula male reproductive apparatus. We performed morphometry and ultrastructure characterization of corpora allata, testes, seminal vesicles and accessory glands in parasitized and unparasitized males, and also in young and old males to control for the effect of age on the natural deterioration of these organs. Our results show that age significantly affects the development of male reproductive apparatus. A low parasite load - one parasite per host is the common prevalence in the field - has only a marginal impact on the reproductive morphology of P. dominula males, affecting quantitatively but not qualitatively the protein content of male accessory glands. Thus, in male P. dominula wasps, X. vesparum appears to behave as a true "parasite", in clear opposition to the role of "parasitoid" that it takes in female hosts where castration causes the reproductive death. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phylogenetics of Saccharomycetales, the ascomycete yeasts.

PubMed

Suh, Sung-Oui; Blackwell, Meredith; Kurtzman, Cletus P; Lachance, Marc-André

2006-01-01

Ascomycete yeasts (phylum Ascomycota: subphylum Saccharomycotina: class Saccharomycetes: order Saccharomycetales) comprise a monophyletic lineage with a single order of about 1000 known species. These yeasts live as saprobes, often in association with plants, animals and their interfaces. A few species account for most human mycotic infections, and fewer than 10 species are plant pathogens. Yeasts are responsible for important industrial and biotechnological processes, including baking, brewing and synthesis of recombinant proteins. Species such as Saccharomyces cerevisiae are model organisms in research, some of which led to a Nobel Prize. Yeasts usually reproduce asexually by budding, and their sexual states are not enclosed in a fruiting body. The group also is well defined by synapomorphies visible at the ultrastructural level. Yeast identification and classification changed dramatically with the availability of DNA sequencing. Species identification now benefits from a constantly updated sequence database and no longer relies on ambiguous growth tests. A phylogeny based on single gene analyses has shown the order to be remarkably divergent despite morphological similarities among members. The limits of many previously described genera are not supported by sequence comparisons, and multigene phylogenetic studies are under way to provide a stable circumscription of genera, families and orders. One recent multigene study has resolved species of the Saccharomycetaceae into genera that differ markedly from those defined by analysis of morphology and growth responses, and similar changes are likely to occur in other branches of the yeast tree as additional sequences become available.

Growth cones are actively influenced by substrate-bound adhesion molecules.

PubMed

Burden-Gulley, S M; Payne, H R; Lemmon, V

1995-06-01

As axons advance to appropriate target tissues during development, their growth cones encounter a variety of cell adhesion molecules (CAMs) and extracellular matrix molecules (ECM molecules). Purified CAMs and ECM molecules influence neurite outgrowth in vitro and are thought to have a similar function in vivo. For example, when retinal ganglion cell (RGC) neurons are grown on different CAM and ECM molecule substrates in vitro, their growth cones display distinctive morphologies (Payne et al., 1992). Similarly, RGC growth cones in vivo have distinctive shapes at different points in the pathway from the eye to the tectum, suggesting the presence of localized cues that determine growth cone behaviors such as pathway selection at choice points. In this report, time-lapse video microscopy was utilized to examine dynamic transformations of RGC growth cones as they progressed from L1/8D9, N-cadherin, or laminin onto a different substrate. Contact made by the leading edge of a growth cone with a new substrate resulted in a rapid and dramatic alteration in growth cone morphology. In some cases, the changes encompassed the entire growth cone including those regions not in direct contact with the new substrate. In addition, the growth cones displayed a variety of behavioral responses that were dependent upon the order of substrate contact. These studies demonstrate that growth cones are actively affected by the substrate, and suggest that abrupt changes in the molecular composition of the growth cone environment are influential during axonal pathfinding.

Invasive earthworms deplete key soil inorganic nutrients (Ca, Mg, K, and P) in a northern hardwood forest

Treesearch

Kit Resner; Kyungsoo Yoo; Stephen D. Sebestyen; Anthony Aufdenkampe; Cindy Hale; Amy Lyttle; Alex Blum

2015-01-01

Hardwood forests of the Great Lakes Region have evolved without earthworms since the Last Glacial Maximum, but are now being invaded by exotic earthworms introduced through agriculture, fishing, and logging. These exotic earthworms are known to increase soil mixing, affect soil carbon storage, and dramatically alter soil morphology. Here we show, using an active...

Revision and Microtomography of the Pheidole knowlesi Group, an Endemic Ant Radiation in Fiji (Hymenoptera, Formicidae, Myrmicinae)Myrmicinae).

PubMed

Fischer, Georg; Sarnat, Eli M; Economo, Evan P

2016-01-01

The Fijian islands, a remote archipelago in the southwestern Pacific, are home to a number of spectacular endemic radiations of plants and animals. Unlike most Pacific archipelagos, these evolutionary radiations extend to social insects, including ants. One of the most dramatic examples of ant radiation in Fiji has occurred in the hyperdiverse genus Pheidole. Most of the 17 native Fijian Pheidole belong to one of two species groups that descended from a single colonization, yet have evolved dramatically contrasting morphologies: the spinescent P. roosevelti species group, and the more morphologically conservative P. knowlesi species group. Here we revise the knowlesi group, in light of recent phylogenetic results, and enhanced with modern methods of X-ray microtomography. We recognize six species belonging to this group, including two of which we describe as new: Pheidole caldwelli Mann, Pheidole kava sp. n., Pheidole knowlesi Mann, P. ululevu sp. n., P. vatu Mann, and P. wilsoni Mann. Detailed measurements and descriptions, identification keys, and high-resolution images for queens, major and minor workers are provided. In addition, we include highly detailed 3D surface reconstructions for all available castes.

Dramatic Teaching for Dramatic Learning

ERIC Educational Resources Information Center

Graves, Julie

2010-01-01

Ressler's "Dramatic Changes" is a powerful guide for anyone brave enough to create a space for young people to discuss sexual orientation and gender identity. Her accessible style and tangible suggestions describe a creative and educationally sound approach to supporting youth in thoughtfully wrestling with one of the most controversial social…

Spectroscopic ellipsometry investigation of the optical properties of graphene oxide dip-coated on magnetron sputtered gold thin films

NASA Astrophysics Data System (ADS)

Politano, Grazia Giuseppina; Vena, Carlo; Desiderio, Giovanni; Versace, Carlo

2018-02-01

Despite intensive investigations on graphene oxide-gold nanocomposites, the interaction of graphene oxide sheets with magnetron sputtered gold thin films has not been studied yet. The optical constants of graphene oxide thin films dip-coated on magnetron sputtered gold thin films were determined by spectroscopic ellipsometry in the [300-1000] wavelength range. Moreover, the morphologic properties of the samples were investigated by SEM analysis. Graphene oxide absorbs mainly in the ultraviolet region, but when it is dip-coated on magnetron sputtered gold thin films, its optical constants show dramatic changes, becoming absorbing in the visible region, with a peak of the extinction coefficient at 3.1 eV. Using magnetron sputtered gold thin films as a substrate for graphene oxide thin films could therefore be the key to enhance graphene oxide optical sheets' properties for several technological applications, preserving their oxygen content and avoiding the reduction process.

THE EXTRAORDINARY MULTI-TAILED MAIN-BELT COMET P/2013 P5

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

Jewitt, David; Agarwal, Jessica; Weaver, Harold

2013-11-20

Hubble Space Telescope observations of main-belt comet P/2013 P5 reveal an extraordinary system of six dust tails that distinguish this object from any other. Observations two weeks apart show dramatic morphological change in the tails while providing no evidence for secular fading of the object as a whole. Each tail is associated with a unique ejection date, revealing continued, episodic mass loss from the 0.24 ± 0.04 km radius nucleus over the last five months. As an inner-belt asteroid and probable Flora family member, the object is likely to be highly metamorphosed and unlikely to contain ice. The protracted periodmore » of dust release appears inconsistent with an impact origin, but may be compatible with a body that is losing mass through a rotational instability. We suggest that P/2013 P5 has been accelerated to breakup speed by radiation torques.« less

Monolayer-Mediated Growth of Organic Semiconductor Films with Improved Device Performance.

PubMed

Huang, Lizhen; Hu, Xiaorong; Chi, Lifeng

2015-09-15

Increased interest in wearable and smart electronics is driving numerous research works on organic electronics. The control of film growth and patterning is of great importance when targeting high-performance organic semiconductor devices. In this Feature Article, we summarize our recent work focusing on the growth, crystallization, and device operation of organic semiconductors intermediated by ultrathin organic films (in most cases, only a monolayer). The site-selective growth, modified crystallization and morphology, and improved device performance of organic semiconductor films are demonstrated with the help of the inducing layers, including patterned and uniform Langmuir-Blodgett monolayers, crystalline ultrathin organic films, and self-assembled polymer brush films. The introduction of the inducing layers could dramatically change the diffusion of the organic semiconductors on the surface and the interactions between the active layer with the inducing layer, leading to improved aggregation/crystallization behavior and device performance.

Parvoviral nuclear import: bypassing the host nuclear-transport machinery.

PubMed

Cohen, Sarah; Behzad, Ali R; Carroll, Jeffrey B; Panté, Nelly

2006-11-01

The parvovirus Minute virus of mice (MVM) is a small DNA virus that replicates in the nucleus of its host cells. However, very little is known about the mechanisms underlying parvovirus' nuclear import. Recently, it was found that microinjection of MVM into the cytoplasm of Xenopus oocytes causes damage to the nuclear envelope (NE), suggesting that the nuclear-import mechanism of MVM involves disruption of the NE and import through the resulting breaks. Here, fluorescence microscopy and electron microscopy were used to examine the effect of MVM on host-cell nuclear structure during infection of mouse fibroblast cells. It was found that MVM caused dramatic changes in nuclear shape and morphology, alterations of nuclear lamin immunostaining and breaks in the NE of infected cells. Thus, it seems that the unusual nuclear-import mechanism observed in Xenopus oocytes is in fact used by MVM during infection of host cells.

Over-limiting Current and Control of Dendritic Growth by Surface Conduction in Nanopores

PubMed Central

Han, Ji-Hyung; Khoo, Edwin; Bai, Peng; Bazant, Martin Z.

2014-01-01

Understanding over-limiting current (faster than diffusion) is a long-standing challenge in electrochemistry with applications in desalination and energy storage. Known mechanisms involve either chemical or hydrodynamic instabilities in unconfined electrolytes. Here, it is shown that over-limiting current can be sustained by surface conduction in nanopores, without any such instabilities, and used to control dendritic growth during electrodeposition. Copper electrodeposits are grown in anodized aluminum oxide membranes with polyelectrolyte coatings to modify the surface charge. At low currents, uniform electroplating occurs, unaffected by surface modification due to thin electric double layers, but the morphology changes dramatically above the limiting current. With negative surface charge, growth is enhanced along the nanopore surfaces, forming surface dendrites and nanotubes behind a deionization shock. With positive surface charge, dendrites avoid the surfaces and are either guided along the nanopore centers or blocked from penetrating the membrane. PMID:25394685

Mitosis-specific phosphorylation of PML at T409 regulates spindle checkpoint.

PubMed

Jin, J; Liu, J

2016-08-31

During mitosis, Promyelocytic leukemia nuclear bodies (PML NBs) change dramatically in morphology and composition, but little is known about function of PML in mitosis. Here, we show that PML is phosphorylated at T409 (PML p409) in a mitosis-specific manner. More importantly, PML p409 contributes to maintain the duration of pro-metaphase and regulates spindle checkpoint. Deficient PML p409 caused a shortening of pro-metaphase and challenged the nocodazole-triggered mitotic arrest. T409A mutation led to a higher frequency of misaligned chromosomes on metaphase plate, and subsequently death in late mitosis. In addition, inhibition of PML p409 repressed growth of tumor cells, suggesting that PML p409 is a potential target for cancer therapy. Collectively, our study demonstrated an important phosphorylated site of PML, which contributed to explore the role of PML in mitosis.

MHY1 Encodes a C2H2-Type Zinc Finger Protein That Promotes Dimorphic Transition in the Yeast Yarrowia lipolytica

PubMed Central

Hurtado, Cleofe A. R.; Rachubinski, Richard A.

1999-01-01

The yeast-to-hypha morphological transition (dimorphism) is typical of many pathogenic fungi. Dimorphism has been attributed to changes in temperature and nutritional status and is believed to constitute a mechanism of response to adverse conditions. We have isolated and characterized a gene, MHY1, whose transcription is dramatically increased during the yeast-to-hypha transition in Yarrowia lipolytica. Deletion of MHY1 is viable and has no effect on mating, but it does result in a complete inability of cells to undergo mycelial growth. MHY1 encodes a C2H2-type zinc finger protein, Mhy1p, which can bind putative cis-acting DNA stress response elements, suggesting that Mhy1p may act as a transcription factor. Interestingly, Mhy1p tagged with a hemagglutinin epitope was concentrated in the nuclei of actively growing cells found at the hyphal tip. PMID:10322005

Abnormal cell-intrinsic and network excitability in the neocortex of serotonin-deficient Pet-1 knockout mice.

PubMed

Puzerey, Pavel A; Kodama, Nathan X; Galán, Roberto F

2016-02-01

Neurons originating from the raphe nuclei of the brain stem are the exclusive source of serotonin (5-HT) to the cortex. Their serotonergic phenotype is specified by the transcriptional regulator Pet-1, which is also necessary for maintaining their neurotransmitter identity across development. Transgenic mice in which Pet-1 is genetically ablated (Pet-1(-/-)) show a dramatic reduction (∼80%) in forebrain 5-HT levels, yet no investigations have been carried out to assess the impact of such severe 5-HT depletion on the function of target cortical neurons. Using whole cell patch-clamp methods, two-dimensional (2D) multielectrode arrays (MEAs), 3D morphological neuronal reconstructions, and animal behavior, we investigated the impact of 5-HT depletion on cortical cell-intrinsic and network excitability. We found significant changes in several parameters of cell-intrinsic excitability in cortical pyramidal cells (PCs) as well as an increase in spontaneous synaptic excitation through 5-HT3 receptors. These changes are associated with increased local network excitability and oscillatory activity in a 5-HT2 receptor-dependent manner, consistent with previously reported hypersensitivity of cortical 5-HT2 receptors. PC morphology was also altered, with a significant reduction in dendritic complexity that may possibly act as a compensatory mechanism for increased excitability. Consistent with this interpretation, when we carried out experiments with convulsant-induced seizures to asses cortical excitability in vivo, we observed no significant differences in seizure parameters between wild-type and Pet-1(-/-) mice. Moreover, MEA recordings of propagating field potentials showed diminished propagation of activity across the cortical sheath. Together these findings reveal novel functional changes in neuronal and cortical excitability in mice lacking Pet-1. Copyright © 2016 the American Physiological Society.

Elucidating the Role of Injury-Induced Electric Fields (EFs) in Regulating the Astrocytic Response to Injury in the Mammalian Central Nervous System

PubMed Central

Baer, Matthew L.; Henderson, Scott C.; Colello, Raymond J.

2015-01-01

Injury to the vertebrate central nervous system (CNS) induces astrocytes to change their morphology, to increase their rate of proliferation, and to display directional migration to the injury site, all to facilitate repair. These astrocytic responses to injury occur in a clear temporal sequence and, by their intensity and duration, can have both beneficial and detrimental effects on the repair of damaged CNS tissue. Studies on highly regenerative tissues in non-mammalian vertebrates have demonstrated that the intensity of direct-current extracellular electric fields (EFs) at the injury site, which are 50–100 fold greater than in uninjured tissue, represent a potent signal to drive tissue repair. In contrast, a 10-fold EF increase has been measured in many injured mammalian tissues where limited regeneration occurs. As the astrocytic response to CNS injury is crucial to the reparative outcome, we exposed purified rat cortical astrocytes to EF intensities associated with intact and injured mammalian tissues, as well as to those EF intensities measured in regenerating non-mammalian vertebrate tissues, to determine whether EFs may contribute to the astrocytic injury response. Astrocytes exposed to EF intensities associated with uninjured tissue showed little change in their cellular behavior. However, astrocytes exposed to EF intensities associated with injured tissue showed a dramatic increase in migration and proliferation. At EF intensities associated with regenerating non-mammalian vertebrate tissues, these cellular responses were even more robust and included morphological changes consistent with a regenerative phenotype. These findings suggest that endogenous EFs may be a crucial signal for regulating the astrocytic response to injury and that their manipulation may be a novel target for facilitating CNS repair. PMID:26562295

Formation of Nanosized Defective Lithium Peroxides through Si-Coated Carbon Nanotube Cathodes for High Energy Efficiency Li-O2 Batteries.

PubMed

Lin, Qi; Cui, Zhonghui; Sun, Jiyang; Huo, Hanyu; Chen, Cheng; Guo, Xiangxin

2018-06-06

The formation and decomposition of lithium peroxides (Li 2 O 2 ) during cycling is the key process for the reversible operation of lithium-oxygen batteries. The manipulation of such products from the large toroidal particles about hundreds of nanometers to the ones in the scale of tens of nanometers can improve the energy efficiency and the cycle life of the batteries. In this work, we carry out an in situ morphology tuning of Li 2 O 2 by virtue of the surface properties of the n-type Si-modified aligned carbon nanotube (CNT) cathodes. With the introduction of an n-type Si coating layer on the CNT surface, the morphology of Li 2 O 2 formed by discharge changes from large toroidal particles (∼300 nm) deposited on the pristine CNT cathodes to nanoparticles (10-20 nm) with poor crystallinity and plenty of lithium vacancies. Beneficial from such changes, the charge overpotential dramatically decreases to 0.55 V, with the charge plateau lying at 3.5 V even in the case of a high discharge capacity (3450 mA h g -1 ) being delivered, resulting in the high electrical energy efficiency approaching 80%. Such an improvement is attributed to the fact that the introduction of the n-type Si coating layer changes the surface properties of CNTs and guides the formation of nanosized amorphous-like lithium peroxides with plenty of defects. These results demonstrate that the cathode surface properties play an important role in the formation of products formed during the cycle, providing inspiration to design superior cathodes for the Li-O 2 cells.

Abnormal cell-intrinsic and network excitability in the neocortex of serotonin-deficient Pet-1 knockout mice

PubMed Central

Puzerey, Pavel A.; Kodama, Nathan X.

2015-01-01

Neurons originating from the raphe nuclei of the brain stem are the exclusive source of serotonin (5-HT) to the cortex. Their serotonergic phenotype is specified by the transcriptional regulator Pet-1, which is also necessary for maintaining their neurotransmitter identity across development. Transgenic mice in which Pet-1 is genetically ablated (Pet-1−/−) show a dramatic reduction (∼80%) in forebrain 5-HT levels, yet no investigations have been carried out to assess the impact of such severe 5-HT depletion on the function of target cortical neurons. Using whole cell patch-clamp methods, two-dimensional (2D) multielectrode arrays (MEAs), 3D morphological neuronal reconstructions, and animal behavior, we investigated the impact of 5-HT depletion on cortical cell-intrinsic and network excitability. We found significant changes in several parameters of cell-intrinsic excitability in cortical pyramidal cells (PCs) as well as an increase in spontaneous synaptic excitation through 5-HT3 receptors. These changes are associated with increased local network excitability and oscillatory activity in a 5-HT2 receptor-dependent manner, consistent with previously reported hypersensitivity of cortical 5-HT2 receptors. PC morphology was also altered, with a significant reduction in dendritic complexity that may possibly act as a compensatory mechanism for increased excitability. Consistent with this interpretation, when we carried out experiments with convulsant-induced seizures to asses cortical excitability in vivo, we observed no significant differences in seizure parameters between wild-type and Pet-1−/− mice. Moreover, MEA recordings of propagating field potentials showed diminished propagation of activity across the cortical sheath. Together these findings reveal novel functional changes in neuronal and cortical excitability in mice lacking Pet-1. PMID:26609119

From Clinging to Digging: The Postembryonic Skeletal Ontogeny of the Indian Purple Frog, Nasikabatrachus sahyadrensis (Anura: Nasikabatrachidae)

PubMed Central

Senevirathne, Gayani; Thomas, Ashish; Kerney, Ryan; Hanken, James; Biju, S. D.; Meegaskumbura, Madhava

2016-01-01

The Indian Purple frog, Nasikabatrachus sahyadrensis, occupies a basal phylogenetic position among neobatrachian anurans and has a very unusual life history. Tadpoles have a large ventral oral sucker, which they use to cling to rocks in torrents, whereas metamorphs possess adaptations for life underground. The developmental changes that underlie these shifts in habits and habitats, and especially the internal remodeling of the cranial and postcranial skeleton, are unknown. Using a nearly complete metamorphic series from free-living larva to metamorph, we describe the postembryonic skeletal ontogeny of this ancient and unique monotypic lineage. The torrent-dwelling larva possesses a dorsoventrally flattened body and a head with tiny dorsal eyes, robust lower and upper jaw cartilages, well-developed trabecular horns, and a definable gap between the trabecular horns and the tip of the snout. Unlike tadpoles of many other frogs, those of Nasikabatrachus retain larval mouthparts into late metamorphic stages. This unusual feature enables the larvae to maintain their clinging habit until near the end of metamorphosis. The subsequent ontogenetic shift from clinging to digging is correlated with rapid morphological changes and behavioral modifications. Metamorphs are equipped with a shortened tibiafibula and ossified prehallical elements, which likely facilitate initial digging using the hind limbs. Subsequently, the frogs may shift to headfirst burrowing by using the wedge-shaped skull, anteriorly positioned pectoral girdle, well-developed humeral crests and spatula-shaped forelimbs. The transition from an aquatic life in torrents to a terrestrial life underground entails dramatic changes in skeletal morphology and function that represent an extreme in metamorphic remodeling. Our analysis enhances the scope for detailed comparative studies across anurans, a group renowned for the diversity of its life history strategies. PMID:27028113

The Role of Electron Microscopy in Studying the Continuum of Changes in Membranous Structures during Poliovirus Infection

PubMed Central

Rossignol, Evan D.; Yang, Jie E.; Bullitt, Esther

2015-01-01

Replication of the poliovirus genome is localized to cytoplasmic replication factories that are fashioned out of a mixture of viral proteins, scavenged cellular components, and new components that are synthesized within the cell due to viral manipulation/up-regulation of protein and phospholipid synthesis. These membranous replication factories are quite complex, and include markers from multiple cytoplasmic cellular organelles. This review focuses on the role of electron microscopy in advancing our understanding of poliovirus RNA replication factories. Structural data from the literature provide the basis for interpreting a wide range of biochemical studies that have been published on virus-induced lipid biosynthesis. In combination, structural and biochemical experiments elucidate the dramatic membrane remodeling that is a hallmark of poliovirus infection. Temporal and spatial membrane modifications throughout the infection cycle are discussed. Early electron microscopy studies of morphological changes following viral infection are re-considered in light of more recent data on viral manipulation of lipid and protein biosynthesis. These data suggest the existence of distinct subcellular vesicle populations, each of which serves specialized roles in poliovirus replication processes. PMID:26473912

Influence of zeolite precipitation on borosilicate glass alteration under hyperalkaline conditions

NASA Astrophysics Data System (ADS)

Mercado-Depierre, S.; Fournier, M.; Gin, S.; Angeli, F.

2017-08-01

This study enables a better understanding of how nucleation-growth of zeolites affects glass dissolution kinetics in hyperalkaline solutions characteristic of cement waters. A 20-oxide borosilicate glass, an inactive surrogate of a typical intermediate level waste glass, was altered in static mode at 50 °C in a hyperalkaline solution rich in Na+, K+ and Ca2+ and at an initial pH50°C of 12.6. Experiments were performed at four glass-surface-area-to-solution-volume (S/V) ratios to investigate various reaction progresses. Two types of glass alteration kinetics were obtained: (i) at low S/V, a sharp alteration resumption occurred after a rate drop regime, (ii) at high S/V, a high dissolution rate was maintained throughout the test duration with a slight progressive slow-down. In all the experiments, zeolites precipitated but the time taken to form stable zeolite nuclei varied dramatically depending on the S/V. Resulting changes in pH affected zeolite composition, morphology, solubility and growth rate. A change in a critical parameter such as S/V affected all the processes controlling glass dissolution.

Effects of Fragmented Fe Intermetallic Compounds on Ductility in Al-Si-Mg Alloys.

PubMed

Kim, JaeHwang; Kim, DaeHwan

2018-03-01

Fe is intentionally added in order to form the Fe intermetallic compounds (Fe-IMCs) during casting. Field emission scanning electron microscope with energy dispersive spectrometer (EDS) was conducted to understand microstructural changes and chemical composition analyses. The needlelike Fe-IMCs based on two dimensional observation with hundreds of micro size are modified to fragmented particles with the minimum size of 300 nm through clod rolling with 80% thickness reduction. The ratio of Fe:Si on the fragmented Fe-IMCs after 80% reduction is close to 1:1, representing the β-Al5FeSi. The yield and tensile strengths are increased with increasing reduction rate. On the other hand, the elongation is decreased with the 40% reduction, but slightly increased with the 60% reduction. The elongation is dramatically increased over two times for the specimen of 80% reduction compared with that of the as-cast. Fracture behavior is strongly affected by the morphology and size of Fe-IMCs. The fracture mode is changed from brittle to ductile with the microstructure modification of Fe-IMCs.

The role of astrocytes in the hypothalamic response and adaptation to metabolic signals.

PubMed

Chowen, Julie A; Argente-Arizón, Pilar; Freire-Regatillo, Alejandra; Frago, Laura M; Horvath, Tamas L; Argente, Jesús

2016-09-01

The hypothalamus is crucial in the regulation of homeostatic functions in mammals, with the disruption of hypothalamic circuits contributing to chronic conditions such as obesity, diabetes mellitus, hypertension, and infertility. Metabolic signals and hormonal inputs drive functional and morphological changes in the hypothalamus in attempt to maintain metabolic homeostasis. However, the dramatic increase in the incidence of obesity and its secondary complications, such as type 2 diabetes, have evidenced the need to better understand how this system functions and how it can go awry. Growing evidence points to a critical role of astrocytes in orchestrating the hypothalamic response to metabolic cues by participating in processes of synaptic transmission, synaptic plasticity and nutrient sensing. These glial cells express receptors for important metabolic signals, such as the anorexigenic hormone leptin, and determine the type and quantity of nutrients reaching their neighboring neurons. Understanding the mechanisms by which astrocytes participate in hypothalamic adaptations to changes in dietary and metabolic signals is fundamental for understanding the neuroendocrine control of metabolism and key in the search for adequate treatments of metabolic diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

Laminin alterations after in vitro nonenzymatic glycosylation.

PubMed

Charonis, A S; Reger, L A; Dege, J E; Kouzi-Koliakos, K; Furcht, L T; Wohlhueter, R M; Tsilibary, E C

1990-07-01

Laminin, a basement membrane protein derived from the matrix of the Engelbreth-Holm-Swarm murine tumor, was nonenzymatically glycosylated in vitro in the presence of increasing glucose concentrations. The amount of glucose incorporated per laminin molecule was shown to be proportional to the molarity of glucose used. Nonenzymatic glycosylation resulted in formation of cross-links and alterations of the cruciform shape of laminin molecules; these alterations were dramatic when high concentrations of glucose were used. One of the functions of laminin, the process of self-assembly, was shown to be impaired after in vitro nonenzymatic glycosylation. Glucose incorporation resulted in a dramatic decrease of long-to-long laminin dimers, which normally form during the initial steps of assembly. Furthermore, nonenzymatic glycosylation of laminin reduced its ability to self-associate into complexes larger than dimers, as judged by turbidimetry. The observed decrease of maximal turbidity was proportional to the degree of nonenzymatic glycosylation. Aminoguanidine, which has been suggested to inhibit cross-link formation, was shown to restore to a large extent the shape of laminin, the percentage of long-to-long arm dimers, and the maximal turbidity when included in the mixtures of laminin and glucose. These data suggest that structural and functional alterations of laminin may be primarily due to formation of cross-links. Such modifications of laminin (along with our basement membrane components) may contribute to the morphological and physiological changes observed in basement membranes under diabetic conditions.

Women as Workers.

ERIC Educational Resources Information Center

Barrett, Nancy S.

As increasing numbers of women make the transition from the household sector into the labor market, dramatic changes in household composition have occurred that have thrust many women into the role of provider. This new role for women has led to dramatic and rapid changes in attitudes, as well as in the institutions and laws relating to women's…

The Homeobox BcHOX8 Gene in Botrytis Cinerea Regulates Vegetative Growth and Morphology

PubMed Central

Antal, Zsuzsanna; Rascle, Christine; Cimerman, Agnès; Viaud, Muriel; Billon-Grand, Geneviève; Choquer, Mathias; Bruel, Christophe

2012-01-01

Filamentous growth and the capacity at producing conidia are two critical aspects of most fungal life cycles, including that of many plant or animal pathogens. Here, we report on the identification of a homeobox transcription factor encoding gene that plays a role in these two particular aspects of the development of the phytopathogenic fungus Botrytis cinerea. Deletion of the BcHOX8 gene in both the B. cinerea B05-10 and T4 strains causes similar phenotypes, among which a curved, arabesque-like, hyphal growth on hydrophobic surfaces; the mutants were hence named Arabesque. Expression of the BcHOX8 gene is higher in conidia and infection cushions than in developing appressorium or mycelium. In the Arabesque mutants, colony growth rate is reduced and abnormal infection cushions are produced. Asexual reproduction is also affected with abnormal conidiophore being formed, strongly reduced conidia production and dramatic changes in conidial morphology. Finally, the mutation affects the fungus ability to efficiently colonize different host plants. Analysis of the B. cinerea genome shows that BcHOX8 is one member of a nine putative homeobox genes family. Available gene expression data suggest that these genes are functional and sequence comparisons indicate that two of them would be specific to B. cinerea and its close relative Sclerotinia sclerotiorum. PMID:23133556

Oligodendroglial p130Cas Is a Target of Fyn Kinase Involved in Process Formation, Cell Migration and Survival

PubMed Central

Gonsior, Constantin; Binamé, Fabien; Frühbeis, Carsten; Bauer, Nina M.; Hoch-Kraft, Peter; Luhmann, Heiko J.; Trotter, Jacqueline; White, Robin

2014-01-01

Oligodendrocytes are the myelinating glial cells of the central nervous system. In the course of brain development, oligodendrocyte precursor cells migrate, scan the environment and differentiate into mature oligodendrocytes with multiple cellular processes which recognize and ensheath neuronal axons. During differentiation, oligodendrocytes undergo dramatic morphological changes requiring cytoskeletal rearrangements which need to be tightly regulated. The non-receptor tyrosine kinase Fyn plays a central role in oligodendrocyte differentiation and myelination. In order to improve our understanding of the role of oligodendroglial Fyn kinase, we have identified Fyn targets in these cells. Purification and mass-spectrometric analysis of tyrosine-phosphorylated proteins in response to overexpressed active Fyn in the oligodendrocyte precursor cell line Oli-neu, yielded the adaptor molecule p130Cas. We analyzed the function of this Fyn target in oligodendroglial cells and observed that reduction of p130Cas levels by siRNA affects process outgrowth, the thickness of cellular processes and migration behavior of Oli-neu cells. Furthermore, long term p130Cas reduction results in decreased cell numbers as a result of increased apoptosis in cultured primary oligodendrocytes. Our data contribute to understanding the molecular events taking place during oligodendrocyte migration and morphological differentiation and have implications for myelin formation. PMID:24586768

Nuclear patterns of human breast cancer cells during apoptosis: characterisation by fractal dimension and co-occurrence matrix statistics.

PubMed

Losa, Gabriele A; Castelli, Christian

2005-11-01

An analytical strategy combining fractal geometry and grey-level co-occurrence matrix (GLCM) statistics was devised to investigate ultrastructural changes in oestrogen-insensitive SK-BR3 human breast cancer cells undergoing apoptosis in vitro. Apoptosis was induced by 1 microM calcimycin (A23187 Ca(2+) ionophore) and assessed by measuring conventional cellular parameters during the culture period. SK-BR3 cells entered the early stage of apoptosis within 24 h of treatment with calcimycin, which induced detectable changes in nuclear components, as documented by increased values of most GLCM parameters and by the general reduction of the fractal dimensions. In these affected cells, morphonuclear traits were accompanied by the reduction of distinct gangliosides and loss of unidentifiable glycolipid molecules at the cell surface. All these changes were shown to be involved in apoptosis before the detection of conventional markers, which were only measurable during the active phases of apoptotic cell death. In overtly apoptotic cells treated with 1 microM calcimycin for 72 h, most nuclear components underwent dramatic ultrastructural changes, including marginalisation and condensation of chromatin, as reflected in a significant reduction of their fractal dimensions. Hence, both fractal and GLCM analyses confirm that the morphological reorganisation of nuclei, attributable to a loss of structural complexity, occurs early in apoptosis.

Long-term morphologic evolution of the Hangzhou Bay, China

NASA Astrophysics Data System (ADS)

Wen, W.; Zhijun, D.; Hualiang, X.

2013-12-01

Estuaries are the most productive ecosystems of coastal zones in the world, which are significant to mankind as places of navigation, recreation and commerce as well as extensive and diverse habitats for wildlife. However, most estuary environments in the world had occurred greatly changes in recent decades. These estuaries have suffered from impacts of forcing factors including wave climate, mean sea level change and storm surge, especial to the intensive human activities such as training wall construction, channel dredging, sand mining and dam constructions. Thus, there have been increasing concerns about estuary environment changes under effects of different factors. Riverine loads into the Changjiang Estuary have declined dramatically with the construction of Three Gorges Dam (TGD) in 2003. The morphological evolution of the Hangzhou bay that located the southern proximity of the Yangtze estuary starts to attract increasing attentions due to most material of the Hangzhou bay received from Yangtze estuary. In this paper, historical bathymetric charts were digitized and analyzed within a GIS to provide quantitative estimate of changes in volumes in different regions below 0 m elevation. The results show that Hangzhou bay has experienced a major loss in estuarine volume of about 15% with annual mean sediment deposition rate of 80 million m3/a during the last 75 years. However, there is a large-scale spatial adjustment in Hangzhou bay: Bathymetric changes of the Hangzhou bay can be rapidly shifted within the range of 8-10 classes. Volume of the Jinshanzui upstream of the Hangzhou bay has obviously decreased in the last 75 years, especially during 2003-2008. However, Volume of the southern Hangzhou bay has experienced slowly decrease with minor deposition. The northern Hangzhou bay had largely volume changes with rapidly decrease during 1931-1981, and drastically increase since 2003. Further analysis of the bathymetric data relating to possible factors indicates that hydrodynamic characteristics of the Hangzhou bay and tidal reclamation could have influenced these changes in Hangzhou bay, even though there is sharply decline in suspended sediment discharge (SSD) into the Yangtze estuary. However, SSD from Yangtze estuary was the most significant factor contributing to changes of drastically increase in volume of the northern Hangzhou bay.

Activation and proliferation of lymphocytes and other mammalian cells in microgravity

NASA Technical Reports Server (NTRS)

Cogoli, A.; Cogoli-Greuter, M.

1997-01-01

The experimental findings reviewed in this chapter support the following conclusions: Proliferation. Human T-lymphocytes, associated with monocytes as accessory cells, show dramatic changes in the centrifuge, in the clinostat and in space. In free-floating cells the mitogenic response is depressed by 90% in microgravity, whereas in cells attached to a substratum activation is enhanced by 100% compared to 1-G ground and inflight controls. The duration of phase G1 of the mitotic cycle of HeLa cells is reduced in hypergravity, resulting in an increased proliferation rate. Other systems like Friend cells and WI38 human embryonic lung cells do not show significant changes. Genetic expression and signal transduction. T-lymphocytes and monocytes show important changes in the expression of cytokines like interleukin-1, interleukin-2, interferon-gamma and tumor necrosis factor. The data from space experiments in Spacelab, Space Shuttle mid-deck, and Biokosmos have helped to clarify certain aspects of the mechanism of T-cell activation. Epidermoid A431 cells show changes in the genetic expression of the proto-oncogenes c-fos and c-jun in the clinostat and in sounding rockets. Membrane function, in particular the binding of ligates as first messengers of a signal, is not changed in most of the cell systems in microgravity. Morphology and Mortility. Free cells, lymphocytes in particular, are able to move and form aggregates in microgravity, indicating that cell-cell contacts and cell communications do take place in microgravity. Dramatic morphological and ultrastructural changes are not detected in cells cultured in microgravity. Important experiments with single mammalian cells, including immune cells, were carried out recently in three Spacelab flights, (SL-J, D-2, and IML-2 in 1992, 1993, and 1994, respectively). The results of the D-2 mission have been published in ref. 75; those of the IML-2 mission in ref. 76. Finally, many cell biology experiments in space have suffered in the past from a lack of adequate controls (like 1-G centrifuges) and of proper experimental conditions (like well-controlled temperature). In this respect the availability of Biorack, outfitted with proper incubators with 1-G control centrifuge as well as a glovebox with a microscope, is a great advantage. It is also desirable that cell biology experiments in space are accompanied or even preceded by a program of ground-based investigations in the fast rotating clinostat and in the centrifuge, and that preparatory experiments be done in parabolic flights and sounding rockets, whenever possible. Proper publication of the results of space experiments is another important need. A great number of data have been published in proceedings and reports that are not available to the broad scientific community. To guarantee the credibility and the international recognition of space biology it is important that the results be published in international, peer reviewed journals.

Dramatic Changes in Health Care Professions in the Past 40 Years.

PubMed

Goldfield, Norbert

During the forty-year life of the Journal of Ambulatory Care Management, revolutionary transformations have occurred in the roles of existing health professions, as has the emergence of new categories of health professionals. This paper specifies the reasons for these dramatic changes, the new types of health care professions that have emerged, changes in existing professions, and suggestions of future directions. Many of these changes will be impacted by what occurs in Washington, DC in the debate over the Accountable Care Act.

Effect of captivity on morphology: negligible changes in external morphology mask significant changes in internal morphology

PubMed Central

Munn, Adam J.; Byrne, Phillip G.

2018-01-01

Captive breeding programmes are increasingly relied upon for threatened species management. Changes in morphology can occur in captivity, often with unknown consequences for reintroductions. Few studies have examined the morphological changes that occur in captive animals compared with wild animals. Further, the effect of multiple generations being maintained in captivity, and the potential effects of captivity on sexual dimorphism remain poorly understood. We compared external and internal morphology of captive and wild animals using house mouse (Mus musculus) as a model species. In addition, we looked at morphology across two captive generations, and compared morphology between sexes. We found no statistically significant differences in external morphology, but after one generation in captivity there was evidence for a shift in the internal morphology of captive-reared mice; captive-reared mice (two generations bred) had lighter combined kidney and spleen masses compared with wild-caught mice. Sexual dimorphism was maintained in captivity. Our findings demonstrate that captive breeding can alter internal morphology. Given that these morphological changes may impact organismal functioning and viability following release, further investigation is warranted. If the morphological change is shown to be maladaptive, these changes would have significant implications for captive-source populations that are used for reintroduction, including reduced survivorship.

Multiple beam interference confocal microscopy: a tool for morphological investigation of living cells and tissues

NASA Astrophysics Data System (ADS)

Joshi, Narahari V.; Medina, Honorio

2000-05-01

Multiple beam interference system is used in conjunction with a conventional scanning confocal microscope to examine the morphology and construction of 3D images of Histolytic Ameba and parasite Candida Albicans. The present combination permits to adjoin advantages of both systems, namely the vertical high contrast and optical sectioning. The interference pattern obtained from a multiple internal reflection of a simple, sandwiched between the glass plate and the cover plate, was focussed on an objective of a scanning confocal microscope. According to optical path differences, morphological details were revealed. The combined features, namely improved resolution in z axis, originated from the interference pattern and the optical sectioning of the confocal scanning system, enhance the resolution and contrast dramatically. These features permitted to obtain unprecedented images of Histolytic Ameba and parasite Candida Albicans. Because of the improved contrast, several details like double wall structure of candida, internal structure of ameba are clearly visible.

Expansion of presoldier cuticle contributes to head elongation during soldier differentiation in termites

NASA Astrophysics Data System (ADS)

Sugime, Yasuhiro; Ogawa, Kota; Watanabe, Dai; Shimoji, Hiroyuki; Koshikawa, Shigeyuki; Miura, Toru

2015-12-01

In termites, the soldier caste possesses morphological features suitable for colony defence, despite some exceptions. Soldiers are differentiated via two moultings through a presoldier stage with dramatic morphogenesis. While a number of morphological modifications are known to occur during the presoldier moult, growth and morphogenesis seem to continue even after the moult. The present study, using the damp-wood termite Hodotermopsis sjostedti, carried out morphological and histological investigations on the developmental processes during the presoldier stage that is artificially induced by the application of a juvenile hormone analogue. Measurements of five body parameters indicated that head length significantly increased during the 14-day period after the presoldier moult, while it did not increase subsequently to the stationary moult (pseudergate moult as control). Histological observations also showed that the cuticular development played a role in the presoldier head elongation, suggesting that the soft and flexible presoldier cuticle contributed to the soldier morphogenesis in termites.

Strategies of TV News Dramatization: An Attempt of Discourse Analysis.

ERIC Educational Resources Information Center

Mancini, Paolo

This paper defines indicators related to the dramatization of television and formulates a methodology for analyzing the discourse of the television news based on empirical studies. This methodology is used to isolate some indicators of dramatization as it relates to the structure and form of the message. The changes that have affected the text of…

Immunohistochemical localization of serotonin in the brain during natural sex change in the hermaphroditic goby Lythrypnus dalli.

PubMed

Lorenzi, Varenka; Grober, Matthew S

2012-02-01

The neurotransmitter serotonin (5-HT) may play a central role in the inhibition of socially regulated sex change in fish because of its known modulation of both aggressive and reproductive behavior. This is the first study to use immunohistochemical techniques to examine the morphometry of serotonergic neurons at different times during sex change. Using a model species wherein sex change is socially regulated via agonistic social interactions (the bluebanded goby, Lythrypnus dalli), we sampled brains of males and females with different social status, and of females at different times during sex change. Consistent with previous studies on other teleosts, immunoreactive neurons were found in the posterior periventricular nucleus (NPPv), the nucleus of the lateral recess (NRL), the nucleus of the posterior recess (NRP) and in the raphe nucleus. We measured the total area of NPPv, NRL, NRP, and the number and mean cell area of serotonergic neurons in the raphe nucleus. There was no significant difference in any of the brain regions between males, females or sex changing fish, but there was a slight increase in the number of dorsal raphe neurons in the brain of sex changers 2h after male removal. The results show that in L. dalli the serotonergic system does not present any morphological sex and status differences, nor any dramatic modifications during sex change. These data, together with previous results, do not support the hypothesis that serotonin inhibits socially regulated sex change. Copyright © 2011 Elsevier Inc. All rights reserved.

Toyota's tips drive dramatic ED improvements.

PubMed

2002-11-01

The Toyota Motor Corp.'s key concepts of allowing workers to make changes, putting the customer first, and reducing waste can have a dramatic impact when implemented in emergency departments. Staff should be empowered to make changes to improve quality. A chain of events should be set in motion for each customer request. Identify and eliminate roadblocks that cause delays.

Modeled atoll shoreline and run-up changes in response to sea-level rise and varying large wave conditions at Wake and Midway Atolls, Northwestern Hawaiian Islands

NASA Astrophysics Data System (ADS)

Shope, J. B.; Storlazzi, C. D.; Hoeke, R. K.

2016-12-01

Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. With sea level and wave climates projected to change over the next century, it is unclear how shoreline wave runup and erosion patterns along these low elevation islands will respond, making it difficult for communities to prepare for the future. To investigate this, extreme boreal winter and summer wave conditions under a variety of future sea-level rise (SLR) scenarios were modeled at two atolls, Wake and Midway, using Delft3D. Nearshore wave conditions were used to find the potential longshore sediment flux, and wave-driven shoreline erosion was calculated as the divergence of the longshore drift; runup and the locations where runup exceed the berm elevation were also found. Of the aforementioned parameters, SLR is projected to be the dominant force driving future island morphological change and flooding. Increased sea level reduces depth-limited breaking by the atoll reef, allowing larger waves to reach the shoreline, increasing runup height and driving greater inland flooding along most coastlines. Previously protected shorelines, such as lagoon shorelines or shorelines with comparably wide reef flats, are projected see the greatest relative increases in runup. Increases in inland flooding extent were greatest along seaward shorelines due to increases in runup. Changes in incident wave directions had a smaller effect on runup, and the projected changes to incident wave heights had a negligible effect. SLR also drove the greatest changes to island shoreline morphology. Windward islands are projected to become thinner as seaward and lagoonal shorelines erode, accreting toward more leeward shorelines and shorelines with comparably wider reef flats. Similarly, leeward islands are anticipated to become thinner and longer, accreting towards their longitudinal ends. The shorelines of these islands will likely change dramatically over the next century as SLR and altered wave climates drive new erosional regimes. It is vital to the sustainability of island communities that the relative magnitudes of these effects are addressed when planning for projected future climates.

Reliance of Wolbachia on High Rates of Host Proteolysis Revealed by a Genome-Wide RNAi Screen of Drosophila Cells.

PubMed

White, Pamela M; Serbus, Laura R; Debec, Alain; Codina, Adan; Bray, Walter; Guichet, Antoine; Lokey, R Scott; Sullivan, William

2017-04-01

Wolbachia are gram-negative, obligate, intracellular bacteria carried by a majority of insect species worldwide. Here we use a Wolbachia -infected Drosophila cell line and genome-wide RNA interference (RNAi) screening to identify host factors that influence Wolbachia titer. By screening an RNAi library targeting 15,699 transcribed host genes, we identified 36 candidate genes that dramatically reduced Wolbachia titer and 41 that increased Wolbachia titer. Host gene knockdowns that reduced Wolbachia titer spanned a broad array of biological pathways including genes that influenced mitochondrial function and lipid metabolism. In addition, knockdown of seven genes in the host ubiquitin and proteolysis pathways significantly reduced Wolbachia titer. To test the in vivo relevance of these results, we found that drug and mutant inhibition of proteolysis reduced levels of Wolbachia in the Drosophila oocyte. The presence of Wolbachia in either cell lines or oocytes dramatically alters the distribution and abundance of ubiquitinated proteins. Functional studies revealed that maintenance of Wolbachia titer relies on an intact host Endoplasmic Reticulum (ER)-associated protein degradation pathway (ERAD). Accordingly, electron microscopy studies demonstrated that Wolbachia is intimately associated with the host ER and dramatically alters the morphology of this organelle. Given Wolbachia lack essential amino acid biosynthetic pathways, the reliance of Wolbachia on high rates of host proteolysis via ubiquitination and the ERAD pathways may be a key mechanism for provisioning Wolbachia with amino acids. In addition, the reliance of Wolbachia on the ERAD pathway and disruption of ER morphology suggests a previously unsuspected mechanism for Wolbachia ' s potent ability to prevent RNA virus replication. Copyright © 2017 by the Genetics Society of America.

Why are the seed cones of conifers so diverse at pollination?

PubMed

Losada, Juan M; Leslie, Andrew B

2018-06-08

Form and function relationships in plant reproductive structures have long fascinated biologists. Although the intricate associations between specific pollinators and reproductive morphology have been widely explored among animal-pollinated plants, the evolutionary processes underlying the diverse morphologies of wind-pollinated plants remain less well understood. Here we study how this diversity may have arisen by focusing on two conifer species in the pine family that have divergent reproductive cone morphologies at pollination. Standard histology methods, artificial wind pollination assays and phylogenetic analyses were used in this study. A detailed study of cone ontogeny in these species reveals that variation in the rate at which their cone scales mature means that pollination occurs at different stages in their development, and thus in association with different specific morphologies. Pollination experiments nevertheless indicate that both species effectively capture pollen. In wind-pollinated plants, morphological diversity may result from simple variation in development among lineages rather than selective pressures for any major differences in function or performance. This work also illustrates the broader importance of developmental context in understanding plant form and function relationships; because plant reproductive structures perform many different functions over their lifetime, subtle differences in development may dramatically alter the specific morphologies that they use to meet these demands.

Formation of Specialized Propagules Resistant to Desiccation and Cryopreservation in the Threatened Moss Ditrichum plumbicola (Ditrichales, Bryopsida)

PubMed Central

Rowntree, J. K.; Duckett, J. G.; Mortimer, C. L.; Ramsay, M. M.; Pressel, S.

2007-01-01

Background and Aims Successful cryopreservation of bryophytes is linked to intrinsic desiccation tolerance and survival can be enhanced by pre-treatment with abscisic acid (ABA) and sucrose. The pioneer moss Ditrichum plumbicola is naturally subjected to desiccation in the field but showed unexpectedly low survival of cryopreservation, as well as a poor response to pre-treatment. The effects of the cryopreservation protocol on protonemata of D. plumbicola were investigated in order to explore possible relationships between the production in vitro of cryopreservation-tolerant asexual propagules and the reproductive biology of D. plumbicola in nature. Methods Protonemata were prepared for cryopreservation using a four-step protocol involving encapsulation in sodium alginate, pre-treatment for 2 weeks with ABA and sucrose, desiccation for 6 h and rapid freezing in liquid nitrogen. After each stage, protonemata were prepared for light and electron microscopy and growth on standard medium was monitored. Further samples were prepared for light and electron microscopy at intervals over a 24-h period following removal from liquid nitrogen and re-hydration. Key Results Pre-treatment with ABA and sucrose caused dramatic changes to the protonemata. Growth was arrested and propagules induced with pronounced morphological and cytological changes. Most cells died, but those that survived were characterized by thick, deeply pigmented walls, numerous small vacuoles and lipid droplets in their cytoplasm. Desiccation and cryopreservation elicited no dramatic cytological changes. Cells returned to their pre-dehydration and cryopreservation state within 2 h of re-hydration and/or removal from liquid nitrogen. Regeneration was normal once the ABA/sucrose stimulus was removed. Conclusions The ABA/sucrose pre-treatment induced the formation of highly desiccation- and cryopreservation-tolerant propagules from the protonemata of D. plumbicola. This parallels behaviour in the wild, where highly desiccation-tolerant rhizoids function as perennating organs allowing the moss to endure extreme environmental conditions. An involvement of endogenous ABA in the desiccation tolerance of D. plumbicola is suggested. PMID:17666410

Correlated evolution of beak morphology and song in the neotropical woodcreeper radiation.

PubMed

Derryberry, Elizabeth Perrault; Seddon, Nathalie; Claramunt, Santiago; Tobias, Joseph Andrew; Baker, Adam; Aleixo, Alexandre; Brumfield, Robb Thomas

2012-09-01

Mating signals may diversify as a byproduct of morphological adaptation to different foraging niches, potentially driving speciation. Although many studies have focused on the direct influence of ecological and sexual selection on signal divergence, the role of indirect mechanisms remains poorly understood. Using phenotypic and molecular datasets, we explored the interplay between morphological and vocal evolution in an avian radiation characterized by dramatic beak variation, the Neotropical woodcreepers (Dendrocolaptinae). We found evidence of a trade-off between the rate of repetition of song syllables and frequency bandwidth: slow paced songs had either narrow or wide frequency bandwidths, and bandwidth decreased as song pace increased. This bounded phenotypic space for song structure supports the hypothesis that passerine birds face a motor constraint during song production. Diversification of acoustic characters within this bounded space was correlated with diversification of beak morphology. In particular, species with larger beaks produced slower songs with narrower frequency bandwidths, suggesting that ecological selection on beak morphology influences the diversification of woodcreeper songs. Because songs in turn mediate mate choice and species recognition in birds, these results indicate a broader role for ecology in avian diversification. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Investigating Aerosol Morphology Using Scattering Phase Functions Measured with a Laser Imaging Nephelometer

NASA Astrophysics Data System (ADS)

Manfred, K.; Adler, G. A.; Erdesz, F.; Franchin, A.; Lamb, K. D.; Schwarz, J. P.; Wagner, N.; Washenfelder, R. A.; Womack, C.; Murphy, D. M.

2017-12-01

Particle morphology has important implications for light scattering and radiative transfer, but can be difficult to measure. Biomass burning and other important aerosol sources can generate a mixture of both spherical and non-spherical particle morphologies, and it is necessary to represent these populations correctly in models. We describe a laser imaging nephelometer that measures the unpolarized scattering phase function of bulk aerosol at 375 and 405 nm using a wide-angle lens and CCD. We deployed this instrument to the Missoula Fire Sciences Laboratory to measure biomass burning aerosol morphology from controlled fires during the recent FIREX intensive laboratory study. Total integrated scattering signal agreed with that determined by a cavity ring-down photoacoustic spectrometer system and a traditional integrating nephelometer within instrument uncertainties. We compared measured scattering phase functions at 405 nm to theoretical models for spherical (Mie) and fractal (Rayleigh-Debye-Gans) particle morphologies based on the size distribution reported by an optical particle counter. We show that particle morphology can vary dramatically for different fuel types, and present results for two representative fires (pine tree vs arid shrub). We find that Mie theory is inadequate to describe the actual behavior of realistic aerosols from biomass burning in some situations. This study demonstrates the capabilities of the laser imaging nephelometer instrument to provide real-time, in situ information about dominant particle morphology that is vital for accurate radiative transfer calculations.

Understanding Conversion-Type Electrodes for Lithium Rechargeable Batteries.

PubMed

Yu, Seung-Ho; Feng, Xinran; Zhang, Na; Seok, Jeesoo; Abruña, Héctor D

2018-02-20

The need/desire to lower the consumption of fossil fuels and its environmental consequences has reached unprecedented levels in recent years. A global effort has been undertaken to develop advanced renewable energy generation and especially energy storage technologies, as they would enable a dramatic increase in the effective and efficient use of renewable (and often intermittent) energy sources. The development of electrical energy storage (EES) technologies with high energy and power densities, long life, low cost, and safe use represents a challenge from both the fundamental science and technological application points of view. While the advent and broad deployment of lithium-ion batteries (LIBs) has dramatically changed the EES landscape, their performance metrics need to be greatly enhanced to keep pace with the ever-increasing demands imposed by modern consumer electronics and especially the emerging automotive markets. Current battery technologies are mostly based on the use of a transition metal oxide cathode (e.g., LiCoO 2 , LiFePO 4 , or LiNiMnCoO 2 ) and a graphite anode, both of which depend on intercalation/insertion of lithium ions for operation. While the cathode material currently limits the battery capacity and overall energy density, there is a great deal of interest in the development of high-capacity cathode materials as well as anode materials. Conversion reaction materials have been identified/proposed as potentially high-energy-density alternatives to intercalation-based materials. However, conversion reaction materials react during lithiation to form entirely new products, often with dramatically changed structure and chemistry, by reaction mechanisms that are still not completely understood. This makes it difficult to clearly distinguish the limitations imposed by the mechanism and practical losses from initial particle morphology, synthetic approaches, and electrode preparations. Transition metal compounds such as transition metal oxides, sulfides, fluorides, phosphides, and nitrides can undergo conversion reactions yielding materials with high theoretical capacity (generally from 500 to 1500 mA h g -1 ). In particular, a number of transition metal oxides and sulfides have shown excellent electrochemical properties as high-capacity anode materials. In addition, some transition metal fluorides have shown great potential as cathode materials for Li rechargeable batteries. In this Account we present mechanistic studies, with emphasis on the use of operando methods, of selected examples of conversion-type materials as both potentially high-energy-density anodes and cathodes in EES applications. We also include examples of the conceptually similar conversion-type reactions involving chalcogens and halogens, with emphasis on the Li-S system. In this case we focus on the problems arising from the low electrical conductivities of elemental sulfur and Li 2 S and the "redox shuttle" phenomena of polysulfides. In addition to mechanistic insights from the use of operando methods, we also cover several key strategies in electrode materials design such as controlling the size, morphology, composition, and architecture.

The effect of progressive hearing loss on the morphology of endbulbs of Held and bushy cells.

PubMed

Connelly, Catherine J; Ryugo, David K; Muniak, Michael A

2017-01-01

Studies of congenital and early-onset deafness have demonstrated that an absence of peripheral sound-evoked activity in the auditory nerve causes pathological changes in central auditory structures. The aim of this study was to establish whether progressive acquired hearing loss could lead to similar brain changes that would degrade the precision of signal transmission. We used complementary physiologic hearing tests and microscopic techniques to study the combined effect of both magnitude and duration of hearing loss on one of the first auditory synapses in the brain, the endbulb of Held (EB), along with its bushy cell (BC) target in the anteroventral cochlear nucleus. We compared two hearing mouse strains (CBA/Ca and heterozygous shaker-2 +/- ) against a model of early-onset progressive hearing loss (DBA/2) and a model of congenital deafness (homozygous shaker-2 -/- ), examining each strain at 1, 3, and 6 months of age. Furthermore, we employed a frequency model of the mouse cochlear nucleus to constrain our analyses to regions most likely to exhibit graded changes in hearing function with time. No significant differences in the gross morphology of EB or BC structure were observed in 1-month-old animals, indicating uninterrupted development. However, in animals with hearing loss, both EBs and BCs exhibited a graded reduction in size that paralleled the hearing loss, with the most severe pathology seen in deaf 6-month-old shaker-2 -/- mice. Ultrastructural pathologies associated with hearing loss were less dramatic: minor changes were observed in terminal size but mitochondrial fraction and postsynaptic densities remained relatively stable. These results indicate that acquired progressive hearing loss can have consequences on auditory brain structure, with prolonged loss leading to greater pathologies. Our findings suggest a role for early intervention with assistive devices in order to mitigate long-term pathology and loss of function. Copyright © 2016 Elsevier B.V. All rights reserved.

A Rural School/Community: A Case Study of a Dramatic Turnaround & Its Implications for School Improvement.

ERIC Educational Resources Information Center

Carlson, Robert V.

This paper presents a case study of a rural community exhibiting a dramatic turnaround in community support for a new school bond issue. Demographic change was partly responsible for the change in community attitudes, with two waves of immigration altering the long-term conservative orientation of this community. After a series of failed…

Potential of Targeting PDE1C/2A for Suppressing Metastatic Ovarian Cancers

DTIC Science & Technology

2015-09-01

HGSOC), are marked by profound chromosomal aberrations (gene amplification and loss) rather than recurrent somatic mutations [2-4...forced expression resulted in the induction of vimentin and disappearance of E-cadherin in these cells (Figure 1e). Moreover, these cells became...dramatic increase in the abundance of E-cadherin and disappearance of vimentin in both lines (Figure 5b). In addition, mesenchymal morphology of OVCAR5

Computer-assisted adjuncts for aneurysmal morphologic assessment: toward more precise and accurate approaches

NASA Astrophysics Data System (ADS)

Rajabzadeh-Oghaz, Hamidreza; Varble, Nicole; Davies, Jason M.; Mowla, Ashkan; Shakir, Hakeem J.; Sonig, Ashish; Shallwani, Hussain; Snyder, Kenneth V.; Levy, Elad I.; Siddiqui, Adnan H.; Meng, Hui

2017-03-01

Neurosurgeons currently base most of their treatment decisions for intracranial aneurysms (IAs) on morphological measurements made manually from 2D angiographic images. These measurements tend to be inaccurate because 2D measurements cannot capture the complex geometry of IAs and because manual measurements are variable depending on the clinician's experience and opinion. Incorrect morphological measurements may lead to inappropriate treatment strategies. In order to improve the accuracy and consistency of morphological analysis of IAs, we have developed an image-based computational tool, AView. In this study, we quantified the accuracy of computer-assisted adjuncts of AView for aneurysmal morphologic assessment by performing measurement on spheres of known size and anatomical IA models. AView has an average morphological error of 0.56% in size and 2.1% in volume measurement. We also investigate the clinical utility of this tool on a retrospective clinical dataset and compare size and neck diameter measurement between 2D manual and 3D computer-assisted measurement. The average error was 22% and 30% in the manual measurement of size and aneurysm neck diameter, respectively. Inaccuracies due to manual measurements could therefore lead to wrong treatment decisions in 44% and inappropriate treatment strategies in 33% of the IAs. Furthermore, computer-assisted analysis of IAs improves the consistency in measurement among clinicians by 62% in size and 82% in neck diameter measurement. We conclude that AView dramatically improves accuracy for morphological analysis. These results illustrate the necessity of a computer-assisted approach for the morphological analysis of IAs.

Speciation, Divergence, and the Origin of Gryllus rubens: Behavior, Morphology, and Molecules

PubMed Central

Gray, David A.

2011-01-01

The last 25 years or so has seen a huge resurgence of interest in speciation research. This has coincided with the development and widespread use of new tools in molecular genetics, especially DNA sequencing, to inform ecological and evolutionary questions. Here I review about a decade of work on the sister species of field crickets Gryllus texensis and G. rubens. This work has included analysis of morphology, behavior, and the mitochondrial DNA molecule. The molecular work in particular has dramatically re-shaped my interpretation of the speciational history of these taxa, suggesting that rather than ‘sister’ species we should consider these taxa as ‘mother-daughter’ species with G. rubens derived from within a subset of ancestral G. texensis. PMID:26467622

Organic supernanostructures self-assembled via solution process for explosive detection.

PubMed

Wang, Lei; Zhou, Yan; Yan, Jing; Wang, Jian; Pei, Jian; Cao, Yong

2009-02-03

Three different polymorphic crystalline structures, including microbelts and flowerlike supernanostructures, were obtained via a simple solution process by utilizing different solvents from an oligoarene derivative. Explosive chemosensors based on these self-assembled organic crystalline nanostructures were successfully fabricated. The differences in the structures on the microscopic level and in the film morphologies led to dramatic enhancements of the explosive detection speed. With the evolution of structures from the netted 1D microbelts to the flowerlike supernanostructures, the detection speed of the chemosensors for DNT and TNT was improved by more than 700 times. Our discovery demonstrates that the morphology control through self-assembly provides a new platform to utilize organic crystalline microstructures for chemosensors, optoelectronics, biosensors and bioelectronics, and so forth.

A Sensitive Method for Examining Whole Cell Biochemical Composition in Single Cells of Filamentous Fungi using Synchrotron FTIR Spectromicroscopy

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

Konstantin,J.; Gough, K.; Julian, R.

2008-01-01

Cell function is related to cell composition. The asexual state of filamentous fungi (molds and mildews) has two main life cycle stages: vegetative hyphae for substrate colonization and nutrient acquisition, and asexual spores for survival and dispersal. Hyphal composition changes over a few tens of microns during growth and maturation; spores are different from hyphae. Most biochemical analyses are restricted to studying a few components at high spatial resolution (e.g. histochemistry) or many compounds at low spatial resolution (e.g. GC-MS). Synchrotron FTIR spectromicroscopy can be used to study fungal cell biology by fingerprinting varieties of carbohydrates, proteins, and lipids atmore » about 6 microm spatial resolution. FTIR can distinguish fungal species and changes during hyphal growth, and reveals that even fungi grown under optimal vs mildly stressed conditions exhibit dramatic biochemical changes without obvious morphological effects. Here we compare hypha and spore composition of two fungi, Neurospora and Rhizopus. There are clear biochemical changes when Neurospora hyphae commit to spore development, during spore maturation and following germination, many of which are consistent with results from molecular genetics, but have not been shown before at high spatial resolution. Rhizopus spores develop within a fluid-containing sporangium that becomes dry at maturity. Rhizopus spores had similar protein content and significantly more carbohydrate than the sporangial fluid, both of which are novel findings.« less

Molecular and Neuroendocrine Mechanisms of Avian Seasonal Reproduction.

PubMed

Tamai, T Katherine; Yoshimura, Takashi

2017-01-01

Animals living outside tropical zones experience seasonal changes in the environment and accordingly, adapt their physiology and behavior in reproduction, molting, and migration. Subtropical birds are excellent models for the study of seasonal reproduction because of their rapid and dramatic response to changes in photoperiod. For example, testicular weight typically changes by more than a 100-fold. In birds, the eyes are not necessary for seasonal reproduction, and light is instead perceived by deep brain photoreceptors. Functional genomic analysis has revealed that long day (LD)-induced thyrotropin from the pars tuberalis of the pituitary gland causes local thyroid hormone (TH) activation within the mediobasal hypothalamus. This local bioactive TH, triiodothyronine (T 3 ), appears to regulate seasonal gonadotropin-releasing hormone (GnRH) secretion through morphological changes in neuro-glial interactions. GnRH, in turn, stimulates gonadotropin secretion and hence, gonadal development under LD conditions. In marked contrast, low temperatures accelerate short day (SD)-induced testicular regression in winter. Interestingly, low temperatures increase circulating levels of T 3 to support adaptive thermogenesis, but this induction of T 3 also triggers the apoptosis of germ cells by activating genes involved in metamorphosis. This apparent contradiction in the role of TH has recently been clarified. Central activation of TH during spring results in testicular growth, while peripheral activation of TH during winter regulates adaptive thermogenesis and testicular regression.

The developmental morphology of a "periosteal" ligament insertion: growth and maturation of the tibial insertion of the rabbit medial collateral ligament.

PubMed

Matyas, J R; Bodie, D; Andersen, M; Frank, C B

1990-05-01

The structural properties of ligament insertions change dramatically during growth and maturation, but little is known about their developmental anatomy. This study describes and quantifies changes in the gross and microscopic anatomy of the tibial insertion of the rabbit medial collateral ligament (MCL) during development and at skeletal maturity. Eighty animals were used for growth and descriptive studies. From this group, 27 animals, ranging in age from 1 to 24 months, were injected with fluorescent bone markers and their tibial insertions were processed undecalcified for histology. Sections were examined by polarized light and fluorescence microscopy to identify matrix and cells and to quantify mineral formation. Results showed that animals achieved histological skeletal maturity between 9 and 12 months of age. Body weights were a poor index of skeletal maturity. The tibial insertion was composed of five tissue layers, which changed proportions during growth and maturation. In immature animals, MCL fibers entered the periosteum; in older animals, MCL fibers were cemented to the tibia by advancing mineral. The tibial attachment of the MCL was thus transferred from the periosteum to the cortex during growth, suggesting that the term "periosteal insertion" is imprecise in adults. The hypothesis is put forward that these structural changes account for the reported increase in tensile failure of this insertion near skeletal maturity.

Crystallization of calcium oxalate monohydrate at dipalmitoylphosphatidylcholine monolayers in the presence of chondroitin sulfate A

NASA Astrophysics Data System (ADS)

Ouyang, Jian-Ming; Deng, Sui-Ping; Zhong, Jiu-Ping; Tieke, Bernd; Yu, Shu-Hong

2004-10-01

The growth and aggregation of calcium oxalate monohydrate (COM) crystals beneath dipalmitoylphosphatidylcholine (DPPC) monolayers in the presence of chondroitin sulfate A (C4S) was systematically examined under different surface pressure. The results indicated that the addition of C4S can inhibit the crystal growth and prevent the aggregation of COM crystals. Under a DPPC monolayer, well-defined three-dimensional hexagonal prisms and three-dimensional rhombus prisms with sharply angled tips were obtained. The DPPC monolayer at a surface pressure of 10 mN/m can match the Ca2+ distance of the (1 bar 0 1) face of COM better than at 20 mN/m. The addition of C4S could cooperatively modulate the interaction strength between the monolayer (or itself) with the specific morphology determining faces such as (1 bar 0 1) and (0 2 0), and thus results in remarkable stabilization of the (1 bar 0 1) faces. The dramatic changes in morphological details were due to the strong electrostatic interactions between the Ca2+-rich (1 bar 0 1) crystal faces of COM and the polyanionic polysaccharide C4S together with the negatively charged sites of the zwitterionic DPPC monolayers. The increase of the concentration of C4S can further enhance the stabilization of the (1 bar 0 1) face.

Asymmetric reproductive barriers and mosaic reproductive isolation: insights from Misty lake–stream stickleback

PubMed Central

Räsänen, Katja; Hendry, Andrew P

2014-01-01

Ecological speciation seems to occur readily but is clearly not ubiquitous – and the relative contributions of different reproductive barriers remain unclear in most systems. We here investigate the potential importance of selection against migrants in lake/stream stickleback (Gasterosteus aculeatus) from the Misty Lake system, Canada. This system is of particular interest because one population contrast (Lake vs. Outlet stream) shows very low genetic and morphological divergence, whereas another population contrast (Lake vs. Inlet stream) shows dramatic genetic and morphological divergence apparently without strong and symmetric reproductive barriers. To test whether selection against migrants might solve this “conundrum of missing reproductive isolation”, we performed a fully factorial reciprocal transplant experiment using 225 individually marked stickleback collected from the wild. Relative fitness of the different ecotypes (Lake, Inlet, and Outlet) was assessed based on survival and mass change in experimental enclosures. We found that Inlet fish performed poorly in the lake (selection against migrants in that direction), whereas Lake fish outperformed Inlet fish in all environments (no selection against migrants in the opposite direction). As predicted from their phenotypic and genetic similarity, Outlet and Lake fish performed similarly in all environments. These results suggest that selection against migrants is asymmetric and, together with previous work, indicates that multiple reproductive barriers contribute to reproductive isolation. Similar mosaic patterns of reproductive isolation are likely in other natural systems. PMID:24772291

Fusion, rupture, and degeneration: the fate of in vivo-labelled PSVs in developing barley endosperm *

PubMed Central

Ibl, Verena; Kapusi, Eszter; Arcalis, Elsa; Kawagoe, Yasushi; Stoger, Eva

2014-01-01

Cereal endosperm is a highly differentiated tissue containing specialized organelles for the accumulation of storage proteins. The endosperm of barley contains hordeins, which are ultimately deposited within protein storage vacuoles (PSVs). These organelles have been characterized predominantly by the histochemical analysis of fixed immature tissue samples. However, little is known about the fate of PSVs during barley endosperm development, and in vivo imaging has not been attempted in order to gain further insight. In this report, young seeds were followed through development to characterize the dynamic morphology of PSVs from aleurone, subaleurone, and central starchy endosperm cells. TIP3-GFP was used as a PSV membrane marker and several fluorescent tracers were used to identify membranes and monitor endomembrane organelles in real time. Whereas the spherical appearance of strongly labelled TIP3-GFP PSVs in the aleurone remained constant, those in the subaleurone and central starchy endosperm underwent substantial morphological changes. Fusion and rupture events were observed in the subaleurone, and internal membranes derived from both the tonoplast and endoplasmic reticulum were identified within these PSVs. TIP3-GFP-labelled PSVs in the starchy endosperm cells underwent a dramatic reduction in size, so that finally the protein bodies were tightly enclosed. Potential desiccation-related membrane-altering processes that may be causally linked to these dynamic endomembrane events in the barley endosperm are discussed. PMID:24803499

Stability of an Electrodeposited Nanocrystalline Ni-Based Alloy Coating in Oil and Gas Wells with the Coexistence of H₂S and CO₂.

PubMed

Sui, Yiyong; Sun, Chong; Sun, Jianbo; Pu, Baolin; Ren, Wei; Zhao, Weimin

2017-06-09

The stability of an electrodeposited nanocrystalline Ni-based alloy coating in a H₂S/CO₂ environment was investigated by electrochemical measurements, weight loss method, and surface characterization. The results showed that both the cathodic and anodic processes of the Ni-based alloy coating were simultaneously suppressed, displaying a dramatic decrease of the corrosion current density. The corrosion of the Ni-based alloy coating was controlled by H₂S corrosion and showed general corrosion morphology under the test temperatures. The corrosion products, mainly consisting of Ni₃S₂, NiS, or Ni₃S₄, had excellent stability in acid solution. The corrosion rate decreased with the rise of temperature, while the adhesive force of the corrosion scale increased. With the rise of temperature, the deposited morphology and composition of corrosion products changed, the NiS content in the corrosion scale increased, and the stability and adhesive strength of the corrosion scale improved. The corrosion scale of the Ni-based alloy coating was stable, compact, had strong adhesion, and caused low weight loss, so the corrosion rates calculated by the weight loss method cannot reveal the actual oxidation rate of the coating. As the corrosion time was prolonged, the Ni-based coating was thinned while the corrosion scale thickened. The corrosion scale was closely combined with the coating, but cannot fully prevent the corrosive reactants from reaching the substrate.

Lipophilic organic pollutants induce changes in phospholipid and membrane protein composition leading to Vero cell morphological change.

PubMed

Liao, Ting T; Wang, Lei; Jia, Ru W; Fu, Xiao H; Chua, Hong

2014-01-01

Membrane damage related to morphological change in Vero cells is a sensitive index of the composite biotoxicity of trace lipophilic chemicals. However, judging whether the morphological change in Vero cells happens and its ratio are difficult because it is not a quantitative characteristic. To find biomarkers of cell morphological change for quantitatively representing the ratio of morphological changed cell, the mechanism of cell membrane damage driven by typical lipophilic chemicals, such as trichlorophenol (TCP) and perfluorooctanesulphonate (PFOS), was explored. The ratio of morphologically changed cells generally increased with increased TCP or PFOS concentrations, and the level of four major components of phospholipids varied with concentrations of TCP or PFOS, but only the ratio of phosphatidylcholine (PC)/phosphatidylethanolamine (PE) decreased regularly as TCP or PFOS concentrations increased. Analysis of membrane proteins showed that the level of vimentin in normal cell membranes is high, while it decreases or vanishes after TCP exposure. These variations in phospholipid and membrane protein components may result in membrane leakage and variation in rigid structure, which leads to changes in cell morphology. Therefore, the ratio of PC/PE and amount of vimentin may be potential biomarkers for representing the ratio of morphological changed Vero cell introduced by trace lipophilic compounds, thus their composite bio-toxicity.

Crystallization, Crystal Orientation and Morphology of Poly(ethylene oxide) under 1D Defect-Free Nanoscale Confinement

NASA Astrophysics Data System (ADS)

Hsiao, Ming-Siao; Zheng, Joseph X.; van Horn, Ryan M.; Quirk, Roderic P.; Thomas, Edwin L.; Lotz, Bernard; Cheng, Stephen Z. D.

2009-03-01

One-dimensional (1-D) defect-free nanoscale confinement is created by growing single crystals of PS-b-PEO block copolymers in dilute solution. Those defect-free, 1-D confined lamellae having different PEO layer thicknesses in PS-b-PEO lamellar single crystals (or crystal mats) were used to study the polymer recrystallization and crystal orientation evolution as a function of recrystallization temperature (Trx) because the Tg^PS is larger than Tm^PEO in the PS-b-PEO single crystal. The results are summarized as follows. First, by the combination of electron diffraction and known PEO crystallography, the crystallization of PEO only takes place at Trx<-5^oC. Meanwhile a unique tilted PEO orientation is formed at Trx >-5^oC after self-seeding. The origin of the formation of tilted chains in the PEO crystal will be addressed. Second, from the analysis of 2D WAXD patterns of crystal mats, it is shown that the change in PEO c-axis orientation from homogeneous at low Trx to homeotropic at higher Trx transitions sharply, within 1^oC. The mechanism inducing this dramatic change in crystal orientation will be investigated in detail.

Molecular genetic identification of crustose representatives of the order Corallinales (Rhodophyta) in Chile.

PubMed

Vidal, Rodrigo; Meneses, Isabel; Smith, Macarena

2003-09-01

Knowledge on species of the order Corallinales along the coast of Chile is still scarce despite a number of studies and records of other divisions of seaweeds made since the early 20th century. This lack of information is more dramatic among crustose representatives of the order, thus depriving biogeographic studies of a thorough analysis and resulting in inadequately representative accounts of biodiversity. The currently changing taxonomy of the group makes it difficult to identify and differentiate among taxa based on morphological and developmental characters. Therefore, the use of molecular tools has been adopted in this study in order to facilitate identification and comparison of crustose corallines collected at the rocky intertidal between 27 degrees and 48 degrees S along the Pacific temperate coast of South America. A sequence 600bp (in length) from the SSU-rDNA gene was used to identify five taxa to the genus level: Lithophyllum, Spongites, Mesophyllum, Synarthrophyton, and Leptophytum. In all cases, the genus distinction based on morphological characters coincide with designations based on variation in the ribosomal DNA gene sequence. Spongites is the most frequently occurring genus and is found in all localities sampled while the others appear occasionally. Taxa recognition at species level must be examined with caution considering that morphological variability is not well understood in Chile because the SSU-rDNA region sequence does not always stand alone as an unambiguous means of identifying all coralline species. In such cases, more rapidly evolving markers are needed. For example, sequences from the ITS (rDNA) region often provide greater resolution among closely related species and genera. However, the methodology presented here remains a useful tool for species-level identification.

Biophysics of malarial parasite exit from infected erythrocytes.

PubMed

Chandramohanadas, Rajesh; Park, YongKeun; Lui, Lena; Li, Ang; Quinn, David; Liew, Kingsley; Diez-Silva, Monica; Sung, Yongjin; Dao, Ming; Lim, Chwee Teck; Preiser, Peter Rainer; Suresh, Subra

2011-01-01

Upon infection and development within human erythrocytes, P. falciparum induces alterations to the infected RBC morphology and bio-mechanical properties to eventually rupture the host cells through parasitic and host derived proteases of cysteine and serine families. We used previously reported broad-spectrum inhibitors (E64d, EGTA-AM and chymostatin) to inhibit these proteases and impede rupture to analyze mechanical signatures associated with parasite escape. Treatment of late-stage iRBCs with E64d and EGTA-AM prevented rupture, resulted in no major RBC cytoskeletal reconfiguration but altered schizont morphology followed by dramatic re-distribution of three-dimensional refractive index (3D-RI) within the iRBC. These phenotypes demonstrated several-fold increased iRBC membrane flickering. In contrast, chymostatin treatment showed no 3D-RI changes and caused elevated fluctuations solely within the parasitophorous vacuole. We show that E64d and EGTA-AM supported PV breakdown and the resulting elevated fluctuations followed non-Gaussian pattern that resulted from direct merozoite impingement against the iRBC membrane. Optical trapping experiments highlighted reduced deformability of the iRBC membranes upon rupture-arrest, more specifically in the treatments that facilitated PV breakdown. Taken together, our experiments provide novel mechanistic interpretations on the role of parasitophorous vacuole in maintaining the spherical schizont morphology, the impact of PV breakdown on iRBC membrane fluctuations leading to eventual parasite escape and the evolution of membrane stiffness properties of host cells in which merozoites were irreversibly trapped, recourse to protease inhibitors. These findings provide a comprehensive, previously unavailable, body of information on the combined effects of biochemical and biophysical factors on parasite egress from iRBCs.

Fabrication of high responsivity deep UV photo-detector based on Na doped ZnO nanocolumns

NASA Astrophysics Data System (ADS)

Agrawal, Jitesh; Dixit, Tejendra; Palani, I. A.; Ramachandra Rao, M. S.; Singh, Vipul

2018-05-01

We report a variety of the hydrothermally synthesized ZnO nanostructures with a significant suppression in defect-related emission and huge enhancement in the photo-current to the dark current ratio (approximately six orders of magnitude) upon UV light illumination. Interestingly, the photo-detector shows lower dark current of 1.6 nA with high responsivity of 507 A W‑1 at 254 nm. Here, a systematic analysis of the growth process as well as the physical, chemical and electrical properties of as-grown ZnO nanostructures has been performed. We have utilized the duo effect of both the inorganic (KMnO4) and organic (Na3C6H5O7) additives, which has facilitated the precise tuning of the morphology and intrinsic defects in nanostructures that have made an impact on the photo-responsivity, photoluminescence (PL) and adhesivity of the film on to the underlying substrate. PL analysis of as-grown ZnO nanostructures has suggested 11 times improvement in the near band emission (NBE) to defect level emission (DLE) ratio. Interestingly, thermal annealing of the samples has shown a dramatic change in the morphology with significant improvement in the crystallinity. Notably, the band gap was observed to be modulated from 3.3 eV to 3.1 eV after annealing. In addition to UV photo-detector based applications, the work presented here has provided a subtle solution towards the rectification of various problems pertaining to hydrothermal processes like poor adhesivity, feeble UV emission and problem in precise tuning of the morphology along with the bandgap in one go. Therefore, these investigations assume critical significance towards the development of next-generation optoelectronic devices.

Morphological and biomechanical response to eutrophication and hydrodynamic stresses.

PubMed

Zhu, Guorong; Yuan, Changbo; Di, Guilan; Zhang, Meng; Ni, Leyi; Cao, Te; Fang, Rongting; Wu, Gongguo

2018-05-01

Eutrophication and hydrodynamics determine the final distribution patterns of aquatic macrophytes; however, there is limited available knowledge regarding their interactive effects. Morphological and biomechanical responses to eutrophication and hydrodynamic stresses were assessed by sampling five abundant and dominant species, Potamogeton maackianus, P. pectinatus, P. lucens, Ceratophyllum demersum and Myriophyllum spicatum, in three macrophyte beds in Lake Erhai, Yunnan Province, China: one exposed to eutrophication and moderate southeast (SE) wind; one with mesotrophication, but sheltered by the lakeshore, with weak wind disturbance; and one with meso-eutrophication and strong SE wind. The results showed significant interactive effects of eutrophication and hydrodynamics on most biomechanical traits and some morphological traits, suggesting that aquatic macrophytes preferentially undergo biomechanical adjustments to resist the coexisting eutrophication and hydrodynamic stresses. In particular, hydrodynamics increased both the tensile force and tensile strain of P. maackianus under meso-eutrophication and dramatically decreased them in eutrophic areas, suggesting that eutrophication triggers mechanical failure in this species. Additionally, P. pectinatus, C. demersum and M. spicatum showed the lowest and highest values for the biomechanical variables (greater values for M. spicatum) in the most eutrophic and hydrodynamic areas, respectively, implying that increases in hydrodynamics primarily induce mechanical damage in eutrophic species. The plants generally exhibited greater tensile strain in both shallow and deep waters and the greatest tensile force at moderate depths. The stem cross-sectional area, plant height, stem length, internode length, and branch traits were all responsible for determining the biomechanical variables. This study reveals that hydrodynamic changes primarily induce mechanical damage in eutrophic species, whereas eutrophication triggers mechanical damage in sensitive species. Copyright © 2017. Published by Elsevier B.V.

[Impaired endometrial receptivity in primary infertility in women with undifferentiated connective tissue dysplasia and hereditary thrombophilia].

PubMed

Zanozin, A S; Demura, T A; Kolosovsky, D Yu; Faizullina, N M; Kogan, E A

The concurrence of undifferentiated connective tissue dysplasia (uCTD) and hereditary thrombophilia (HT) often accompanies female infertility, in the pathogenesis of which impaired endometrial receptivity plays an important role. to investigate endometrial morphological and immunophenotypic features in patients with primary infertility in the presence of uCTD and HT. The pipelle endometrial biopsy specimens taken in the implantation window were examined in 81 patients, including 13 women with a clinical diagnosis of uCTD, 40 with HT, 19 with uCTD concurrent with HT, and in a control group of 9 heathy surrogate mothers. Morphological, immunohistochemical, and morphometric examinations were done to study the paraffin-embedded endometrial biopsy sections stained with hematoxylin and eosin, pikrofuksin by van Gieson, and with toluidine blue. Immunohistochemical tests were carried out using primary antibodies against ER, PgR, LIF, PAI-1, VEGF, Collagen I, Collagen III, fibronectin, laminin, MMP-2, and MMP-9. The uCTD, HT, and uCTD + HT groups were found to have signs of decreased endometrial receptivity as dramatically lower counts of mature pinopodes, slower endometrial maturation, reduced expression of the receptivity marker LIF, and deviations of the stromal progesterone-estrogen index from the normal value. Sclerotic foci with type III collagen accumulation were detected in the endometrial stroma. uCTD and HT and especially their concurrence are commonly a concomitant disease and risk factors for infertility in women due to impaired endometrial receptivity. In uCTD, connective tissue remodeling processes are substantially retarded, which ultimately leads to increased processes of endometrial stromal sclerosis, reduced endometrial receptivity, and infertility. The most pronounced morphological and immunophenotypical changes have been ascertained to develop in the uCTD + NT group. The findings may be used to predict and devise new infertility treatments in patients with uCTD + NT.

Characterization and modeling of viscoelastic behavior of carbon nanotube reinforced polymers: The influence of interphase and nanotube morphology

NASA Astrophysics Data System (ADS)

Liu, Hua

The addition of nanoparticles into polymer materials has been observed to dramatically change the mechanical, thermal, electrical, and diffusion properties of the host polymers, promising a novel class of polymer matrix composite materials with superior properties and added functionalities that are ideal candidates in many applications, including aerospace, automobile, medical devices, and sporting goods. Understanding the behavior and underlying mechanisms of these polymer nanocomposites is critical. The research work presented in this dissertation represents one of the initial efforts in the long journey pursuing the ultimate understanding of nanoparticle reinforced polymer systems. Particular focal points are experimental evaluation and the development of appropriate modeling methods to capture the influence of the interphase on the overall viscoelastic behavior of carbon nanotube reinforced polymer nanocomposites. The first portion of this dissertation study investigates the viscoelastic behavior of MWCNT based PMMA nanocomposites, which complements our previous study of SWCNT/PMMA systems to confirm functionalization of nanotubes as an effective way to manipulate the interaction between nanotube and polymers and control the properties of the interphase region forming around the nanotubes and consequently change the overall performance of nanotube based polymer nanocomposites. In the second portion of this dissertation, we present a novel hybrid numerical-analytical modeling method that is capable of predicting viscoelastic behavior of multiphase polymer nanocomposites, in which the nanoscopic fillers can assume complex configurations. By combining the finite element technique and a micromechanical approach (particularly, the Mori-Tanaka method) with local phase properties, this method operates at low computational cost and effectively accounts for the influence of the interphase as well as in situ nanoparticle morphology. This modeling method is implemented two-dimensionally on nanotube and nanoplatelet based polymer nanocomposites. Given the experimentally measured frequency domain response of the bulk polymer, the viscoelastic behavior of the nanocomposites in both frequency and temperature domains can be calculated. The predicted pattern of influence of the interphase on the overall performance of the nanocomposites is consistent with the experimental observation. 3D parametric studies utilizing this modeling technique reveal that the nanotube morphology "modifies" the effect of interphase and hence profoundly influences the overall viscoelastic behavior. The findings help explain some experimental observations and furthermore, draw attention to the importance of morphology control through appropriate synthesis and processing techniques to further tune the thermomechanical behavior of the nanocomposites.

First report of changes in leukocyte morphology in response to inflammatory conditions in Asian and African elephants (Elephas maximus and Loxodonta africana).

PubMed

Stacy, Nicole I; Isaza, Ramiro; Wiedner, Ellen

2017-01-01

Although the hematology of healthy elephants has been well-described, published information on hematological changes during disease is limited. The objective of this study was to describe qualitative morphological changes in the leukocytes of Asian and African elephants (Elephas maximus and Loxodonta africana) diagnosed with a variety of inflammatory conditions. Twenty-five of 27 elephants had morphological changes in their leukocytes, although only 16 of these had a concurrent inflammatory leukogram. Morphological changes included heterophil left-shifting with or without concurrent dysgranulopoiesis, toxicity, or hypersegmentation, reactive lymphocytes, plasma cells, and/or vacuolated monocytes. Although the observed leukocyte morphological changes are non-specific, their early recognition upon blood film evaluation may provide important, clinically-relevant information, particularly if the leukogram is normal. This case series is the first description of qualitative morphological changes in the leukocytes of elephants in association with inflammation.

First report of changes in leukocyte morphology in response to inflammatory conditions in Asian and African elephants (Elephas maximus and Loxodonta africana)

PubMed Central

Isaza, Ramiro; Wiedner, Ellen

2017-01-01

Although the hematology of healthy elephants has been well-described, published information on hematological changes during disease is limited. The objective of this study was to describe qualitative morphological changes in the leukocytes of Asian and African elephants (Elephas maximus and Loxodonta africana) diagnosed with a variety of inflammatory conditions. Twenty-five of 27 elephants had morphological changes in their leukocytes, although only 16 of these had a concurrent inflammatory leukogram. Morphological changes included heterophil left-shifting with or without concurrent dysgranulopoiesis, toxicity, or hypersegmentation, reactive lymphocytes, plasma cells, and/or vacuolated monocytes. Although the observed leukocyte morphological changes are non-specific, their early recognition upon blood film evaluation may provide important, clinically-relevant information, particularly if the leukogram is normal. This case series is the first description of qualitative morphological changes in the leukocytes of elephants in association with inflammation. PMID:28934325

Synthesis and characterization of CaF2:Dy nanophosphor for dosimetric application

NASA Astrophysics Data System (ADS)

Bhadane, Mahesh S.; Patil, B. J.; Dahiwale, S. S.; Kulkarni, M. S.; Bhatt, B. C.; Bhoraskar, V. N.; Dhole, S. D.

2015-06-01

In this work, nanoparticles (NPs) of dysprosium doped calcium fluoride (CaF2:Dy) 1 mol % has been prepared using simple chemical co-precipitation method and its thermoluminescence (TL) dosimetric properties were studied. The synthesized nanoparticle sample was characterized by X-ray diffraction (XRD) and the particle size of face centered cubic phase NPs was found around 30 nm. The shape, morphology and size were also observed by scanning electron microscopy (SEM). From gamma irradiated CaF2:Dy TL curves, it was observed that the total areas of all the glow peak intensities are dramatically changed with increase in annealing temperature. Further, TL glow curve of the CaF2:Dy at 183 °C annealed at 400 °C, showed very sharp linear response in the dose range from 1 Gy to 750 Gy. This linear response of CaF2:Dy nanophosphor as a function of gamma dose is very useful from radiation dosimetric point of view.

Induced unconventional superconductivity on the surface states of Bi2Te3 topological insulator.

PubMed

Charpentier, Sophie; Galletti, Luca; Kunakova, Gunta; Arpaia, Riccardo; Song, Yuxin; Baghdadi, Reza; Wang, Shu Min; Kalaboukhov, Alexei; Olsson, Eva; Tafuri, Francesco; Golubev, Dmitry; Linder, Jacob; Bauch, Thilo; Lombardi, Floriana

2017-12-08

Topological superconductivity is central to a variety of novel phenomena involving the interplay between topologically ordered phases and broken-symmetry states. The key ingredient is an unconventional order parameter, with an orbital component containing a chiral p x  + ip y wave term. Here we present phase-sensitive measurements, based on the quantum interference in nanoscale Josephson junctions, realized by using Bi 2 Te 3 topological insulator. We demonstrate that the induced superconductivity is unconventional and consistent with a sign-changing order parameter, such as a chiral p x  + ip y component. The magnetic field pattern of the junctions shows a dip at zero externally applied magnetic field, which is an incontrovertible signature of the simultaneous existence of 0 and π coupling within the junction, inherent to a non trivial order parameter phase. The nano-textured morphology of the Bi 2 Te 3 flakes, and the dramatic role played by thermal strain are the surprising key factors for the display of an unconventional induced order parameter.

Radial fingering under arbitrary viscosity and density ratios

NASA Astrophysics Data System (ADS)

Anjos, Pedro H. A.; Dias, Eduardo O.; Miranda, José A.

2017-08-01

We study viscous fingering formation in radial Hele-Shaw cell geometry considering the combined action of capillary and inertial effects for arbitrary values of viscosity and density ratios. We tackle the problem by employing a perturbative mode-coupling approach and focus our attention on weakly nonlinear stages of the dynamics. If inertial effects are neglected, our theoretical results indicate that the shape of the resulting interfacial patterns is significantly affected by changes in the viscosity ratio. Under such conditions, the growing fingers tend to proliferate through a repeated ramification process (e.g., by finger bifurcation, quadrifurcation, etc.) as the capillary number is increased. Nevertheless, we find that this scenario is dramatically altered when inertia is taken into account. When inertia is relevant, the conventional finger splitting morphologies are replaced by three-lobed structures, characterized by the occurrence of sidebranching phenomena. We verify that slightly different types of sidebranched patterns arise, presenting either wide or sharp fingertips, for a range of capillary numbers and density ratios.

Finfish and aquatic invertebrate pathology resources for now and the future✩

PubMed Central

Spitsbergen, Jan M.; Blazer, Vicki S.; Bowser, Paul R.; Cheng, Keith C.; Cooper, Keith R.; Cooper, Timothy K.; Frasca, Salvatore; Groman, David B.; Harper, Claudia M.; (Mac) Law, Jerry M.; Marty, Gary D.; Smolowitz, Roxanna M.; Leger, Judy St.; Wolf, Douglas C.; Wolf, Jeffrey C.

2009-01-01

Utilization of finfish and aquatic invertebrates in biomedical research and as environmental sentinels has grown dramatically in recent decades. Likewise the aquaculture of finfish and invertebrates has expanded rapidly worldwide as populations of some aquatic food species and threatened or endangered aquatic species have plummeted due to overharvesting or habitat degradation. This increasing intensive culture and use of aquatic species has heightened the importance of maintaining a sophisticated understanding of pathology of various organ systems of these diverse species. Yet, except for selected species long cultivated in aquaculture, pathology databases and the workforce of highly trained pathologists lag behind those available for most laboratory animals and domestic mammalian and avian species. Several factors must change to maximize the use, understanding, and protection of important aquatic species: 1) improvements in databases of abnormalities across species; 2) standardization of diagnostic criteria for proliferative and nonproliferative lesions; and 3) more uniform and rigorous training in aquatic morphologic pathology. PMID:18948226

Pigmentary and photonic coloration mechanisms reveal taxonomic relationships of the Cattlehearts (Lepidoptera: Papilionidae: Parides)

PubMed Central

2014-01-01

Background The colorful wing patterns of butterflies, a prime example of biodiversity, can change dramatically within closely related species. Wing pattern diversity is specifically present among papilionid butterflies. Whether a correlation between color and the evolution of these butterflies exists so far remained unsolved. Results We here investigate the Cattlehearts, Parides, a small Neotropical genus of papilionid butterflies with 36 members, the wings of which are marked by distinctly colored patches. By applying various physical techniques, we investigate the coloration toolkit of the wing scales. The wing scales contain two different, wavelength-selective absorbing pigments, causing pigmentary colorations. Scale ridges with multilayered lamellae, lumen multilayers or gyroid photonic crystals in the scale lumen create structural colors that are variously combined with these pigmentary colors. Conclusions The pigmentary and structural traits strongly correlate with the taxonomical distribution of Parides species. The experimental findings add crucial insight into the evolution of butterfly wing scales and show the importance of morphological parameter mapping for butterfly phylogenetics. PMID:25064167

Impact of electrical conductivity on acid hydrolysis of guar gum under induced electric field.

PubMed

Li, Dandan; Zhang, Yao; Yang, Na; Jin, Zhengyu; Xu, Xueming

2018-09-01

This study aimed to improve induced electric field (IEF)-assisted hydrolysis of polysaccharide by controlling electrical conductivity. As the conductivity of reaction medium was increased, the energy efficiency of IEF was increased because of deceased impedance, as well as enhanced output voltage and temperature, thus the hydrolysis of guar gum (GG) was accelerated under IEF. Changes in weight-average molecular weight (Mw) suggested that IEF-assisted hydrolysis of GG could be described by the first-order kinetics 1/Mw ∝ kt, with the rate constant (k), varying directly with the medium conductivity. Although IEF-assisted hydrolysis largely disrupted the morphological structure of GG, it had no impact on the chemical structure. In comparison to native GG, the steady shear viscosity of hydrolyzed GG dramatically declined while the thermal stability slightly decreased. This study extended the knowledge of electrical conductivity upon IEF-assisted acid hydrolysis of GG and might contribute to a better utilization of IEF for polysaccharide modification. Copyright © 2018 Elsevier Ltd. All rights reserved.

The functional role for condensin in the regulation of chromosomal organization during the cell cycle.

PubMed

Kagami, Yuya; Yoshida, Kiyotsugu

2016-12-01

In all organisms, the control of cell cycle progression is a fundamental process that is essential for cell growth, development, and survival. Through each cell cycle phase, the regulation of chromatin organization is essential for natural cell proliferation and maintaining cellular homeostasis. During mitosis, the chromatin morphology is dramatically changed to have a "thread-like" shape and the condensed chromosomes are segregated equally into two daughter cells. Disruption of the mitotic chromosome architecture physically impedes chromosomal behaviors, such as chromosome alignment and chromosome segregation; therefore, the proper mitotic chromosome structure is required to maintain chromosomal stability. Accumulating evidence has demonstrated that mitotic chromosome condensation is induced by condensin complexes. Moreover, recent studies have shown that condensin also modulates interphase chromatin and regulates gene expression. This review mainly focuses on the molecular mechanisms that condensin uses to exert its functions during the cell cycle progression. Moreover, we discuss the condensin-mediated chromosomal organization in cancer cells.

Physical Properties of Gas Hydrates: A Review

DOE PAGES

Gabitto, Jorge F.; Tsouris, Costas

2010-01-01

Memore » thane gas hydrates in sediments have been studied by several investigators as a possible future energy resource. Recent hydrate reserves have been estimated at approximately 10 16   m 3 of methane gas worldwide at standard temperature and pressure conditions. In situ dissociation of natural gas hydrate is necessary in order to commercially exploit the resource from the natural-gas-hydrate-bearing sediment. The presence of gas hydrates in sediments dramatically alters some of the normal physical properties of the sediment. These changes can be detected by field measurements and by down-hole logs. An understanding of the physical properties of hydrate-bearing sediments is necessary for interpretation of geophysical data collected in field settings, borehole, and slope stability analyses; reservoir simulation; and production models. This work reviews information available in literature related to the physical properties of sediments containing gas hydrates. A brief review of the physical properties of bulk gas hydrates is included. Detection methods, morphology, and relevant physical properties of gas-hydrate-bearing sediments are also discussed.« less

Symbiotic adaptations in the fungal cultivar of leaf-cutting ants.

PubMed

De Fine Licht, Henrik H; Boomsma, Jacobus J; Tunlid, Anders

2014-12-01

Centuries of artificial selection have dramatically improved the yield of human agriculture; however, strong directional selection also occurs in natural symbiotic interactions. Fungus-growing attine ants cultivate basidiomycete fungi for food. One cultivar lineage has evolved inflated hyphal tips (gongylidia) that grow in bundles called staphylae, to specifically feed the ants. Here we show extensive regulation and molecular signals of adaptive evolution in gene trancripts associated with gongylidia biosynthesis, morphogenesis and enzymatic plant cell wall degradation in the leaf-cutting ant cultivar Leucoagaricus gongylophorus. Comparative analysis of staphylae growth morphology and transcriptome-wide expressional and nucleotide divergence indicate that gongylidia provide leaf-cutting ants with essential amino acids and plant-degrading enzymes, and that they may have done so for 20-25 million years without much evolutionary change. These molecular traits and signatures of selection imply that staphylae are highly advanced coevolutionary organs that play pivotal roles in the mutualism between leaf-cutting ants and their fungal cultivars.

Chemical Characterization and Antitumor Activities of Polysaccharide Extracted from Ganoderma lucidum

PubMed Central

Liang, Zengenni; Yi, Youjin; Guo, Yutong; Wang, Rencai; Hu, Qiulong; Xiong, Xingyao

2014-01-01

Ganoderma lucidum polysaccharide (GLP) is a biologically active substance reported to possess anti-tumor ability. Nonetheless, the mechanisms of GLP-stimulated apoptosis are still unclear. This study aims to determine the inhibitory and apoptosis-inducing effects of GLP on HCT-116 cells. We found that GLP reduced cell viability on HCT-116 cells in a time- and dose-dependent manner, which in turn, induced cell apoptosis. The observed apoptosis was characterized by morphological changes, DNA fragmentation, mitochondrial membrane potential decrease, S phase population increase, and caspase-3 and -9 activation. Furthermore, inhibition of c-Jun N-terminal kinase (JNK) by SP600125 led to a dramatic decrease of the GLP-induced apoptosis. Western blot analysis unveiled that GLP up-regulated the expression of Bax/Bcl-2, caspase-3 and poly (ADP-ribose) polymerase (PARP). These results demonstrate that apoptosis stimulated by GLP in human colorectal cancer cells is associated with activation of mitochondrial and mitogen-activated protein kinase (MAPK) pathways. PMID:24857920

SCFSlimb ubiquitin ligase suppresses condensin II–mediated nuclear reorganization by degrading Cap-H2

PubMed Central

Buster, Daniel W.; Daniel, Scott G.; Nguyen, Huy Q.; Windler, Sarah L.; Skwarek, Lara C.; Peterson, Maureen; Roberts, Meredith; Meserve, Joy H.; Hartl, Tom; Klebba, Joseph E.; Bilder, David; Bosco, Giovanni

2013-01-01

Condensin complexes play vital roles in chromosome condensation during mitosis and meiosis. Condensin II uniquely localizes to chromatin throughout the cell cycle and, in addition to its mitotic duties, modulates chromosome organization and gene expression during interphase. Mitotic condensin activity is regulated by phosphorylation, but mechanisms that regulate condensin II during interphase are unclear. Here, we report that condensin II is inactivated when its subunit Cap-H2 is targeted for degradation by the SCFSlimb ubiquitin ligase complex and that disruption of this process dramatically changed interphase chromatin organization. Inhibition of SCFSlimb function reorganized interphase chromosomes into dense, compact domains and disrupted homologue pairing in both cultured Drosophila cells and in vivo, but these effects were rescued by condensin II inactivation. Furthermore, Cap-H2 stabilization distorted nuclear envelopes and dispersed Cid/CENP-A on interphase chromosomes. Therefore, SCFSlimb-mediated down-regulation of condensin II is required to maintain proper organization and morphology of the interphase nucleus. PMID:23530065

Evolution of king crabs from hermit crab ancestors

NASA Astrophysics Data System (ADS)

Cunningham, C. W.; Blackstone, N. W.; Buss, L. W.

1992-02-01

KING crabs (Family Lithodidae) are among the world's largest arthropods, having a crab-like morphology and a strongly calcified exoskeleton1-6. The hermit crabs, by contrast, have depended on gastropod shells for protection for over 150 million years5,7. Shell-living has constrained the morphological evolution of hermit crabs by requiring a decalcified asymmetrical abdomen capable of coiling into gastropod shells and by preventing crabs from growing past the size of the largest available shells1-6. Whereas reduction in shell-living and acquisition of a crab-like morphology (carcinization) has taken place independently in several hermit crab lineages, and most dramatically in king crabs1-6, the rate at which this process has occurred was entirely unknown2,7. We present molecular evidence that king crabs are not only descended from hermit crabs, but are nested within the hermit crab genus Pagurus. We estimate that loss of the shell-living habit and the complete carcinization of king crabs has taken between 13 and 25 million years.

A Bacterial Parasite Effector Mediates Insect Vector Attraction in Host Plants Independently of Developmental Changes

PubMed Central

Orlovskis, Zigmunds; Hogenhout, Saskia A.

2016-01-01

Parasites can take over their hosts and trigger dramatic changes in host appearance and behavior that are typically interpreted as extended phenotypes that promote parasite survival and fitness. For example, Toxoplasma gondii is thought to manipulate the behaviors of infected rodents to aid transmission to cats and parasitic trematodes of the genus Ribeiroia alter limb development in their amphibian hosts to facilitate predation of the latter by birds. Plant parasites and pathogens also reprogram host development and morphology. However, whereas some parasite-induced morphological alterations may have a direct benefit to the fitness of the parasite and may therefore be adaptive, other host alterations may be side effects of parasite infections having no adaptive effects on parasite fitness. Phytoplasma parasites of plants often induce the development of leaf-like flowers (phyllody) in their host plants, and we previously found that the phytoplasma effector SAP54 generates these leaf-like flowers via the degradation of plant MADS-box transcription factors (MTFs), which regulate all major aspects of development in plants. Leafhoppers prefer to reproduce on phytoplasma-infected and SAP54-trangenic plants leading to the hypothesis that leafhopper vectors are attracted to plants with leaf-like flowers. Surprisingly, here we show that leafhopper attraction occurs independently of the presence of leaf-like flowers. First, the leafhoppers were also attracted to SAP54 transgenic plants without leaf-like flowers and to single leaves of these plants. Moreover, leafhoppers were not attracted to leaf-like flowers of MTF-mutant plants without the presence of SAP54. Thus, the primary role of SAP54 is to attract leafhopper vectors, which spread the phytoplasmas, and the generation of leaf-like flowers may be secondary or a side effect of the SAP54-mediated degradation of MTFs. PMID:27446117

Evolution of a Dark Anti-Cyclone on Saturn Associated with the Great Lightning Storm of 2010/2011 Through the Eyes of Cassini/VIMS

NASA Astrophysics Data System (ADS)

Momary, Thomas W.; Baines, K. H.; Brown, R. H.; Buratti, B. J.; Clark, R. N.; Nicholson, P. D.; Sotin, C.

2012-10-01

A massive dark anti-cyclonic storm system on Saturn spanning some 7∘ of longitude and 2∘ of latitude was observed by Cassini/VIMS at a planetocentric latitude of 37∘ on 4 January 2012 and 26 January 2012. During this time, it drifted some 54∘ of longitude at a speed of 23.1 ± 0.2 m/s prograde, a drift speed which correlates well with the canonical Voyager (and VIMS) wind profiles for Saturn at this latitude. The spot also drifted northward during this time by 1∘ and became noticeably "squished" in morphology. Using this drift rate and extrapolating backward, we find that the position corresponds to the large (> 5,000 km) anti-cyclone observed by VIMS on 11 May 2011 at 35.4∘ latitude (pc) and 49.4∘ W. longitude. This would represent 8 months of observation of this titanic feature, which was associated with the major lightning storm of 2010-2011, following the spot as it changed in size and morphology and drifted northward. The spot underwent a dramatic shift in shape in the 3 weeks of January, changing from roughly oval to a highly elongated pancake shape as it apparently bumped up against the dark band at 40∘ latitude and experienced a powerful shear. The evolution suggests that we are watching the death throes of this feature in our most recent observations. Finally, the dark spot was darker than surrounding regions in May 2011 and maintained its dark color across all pseudo-continua from 1.0 to 4.0 μm between May 2011 and early January 2012.

Morpho-Physiological and Proteome Level Responses to Cadmium Stress in Sorghum

PubMed Central

Kamal, Abu Hena Mostafa; Kim, Sang-Woo; Oh, Myeong-Won; Lee, Moon-Soon; Chung, Keun-Yook; Xin, Zhanguo; Woo, Sun-Hee

2016-01-01

Cadmium (Cd) stress may cause serious morphological and physiological abnormalities in addition to altering the proteome in plants. The present study was performed to explore Cd-induced morpho-physiological alterations and their potential associated mechanisms in Sorghum bicolor leaves at the protein level. Ten-day-old sorghum seedlings were exposed to different concentrations (0, 100, and 150 μM) of CdCl2, and different morpho-physiological responses were recorded. The effects of Cd exposure on protein expression patterns in S. bicolor were investigated using two-dimensional gel electrophoresis (2-DE) in samples derived from the leaves of both control and Cd-treated seedlings. The observed morphological changes revealed that the plants treated with Cd displayed dramatically altered shoot lengths, fresh weights and relative water content. In addition, the concentration of Cd was markedly increased by treatment with Cd, and the amount of Cd taken up by the shoots was significantly and directly correlated with the applied concentration of Cd. Using the 2-DE method, a total of 33 differentially expressed protein spots were analyzed using MALDI-TOF/TOF MS. Of these, treatment with Cd resulted in significant increases in 15 proteins and decreases in 18 proteins. Major changes were absorbed in the levels of proteins known to be involved in carbohydrate metabolism, transcriptional regulation, translation and stress responses. Proteomic results revealed that Cd stress had an inhibitory effect on carbon fixation, ATP production and the regulation of protein synthesis. Our study provides insights into the integrated molecular mechanisms involved in responses to Cd and the effects of Cd on the growth and physiological characteristics of sorghum seedlings. We have aimed to provide a reference describing the mechanisms involved in heavy metal damage to plants. PMID:26919231

Cytotoxicity and physicochemical characterization of iron–manganese-doped sulfated zirconia nanoparticles

PubMed Central

Al-Fahdawi, Mohamed Qasim; Rasedee, Abdullah; Al-Qubaisi, Mothanna Sadiq; Alhassan, Fatah H; Rosli, Rozita; El Zowalaty, Mohamed Ezzat; Naadja, Seïf-Eddine; Webster, Thomas J; Taufiq-Yap, Yun Hin

2015-01-01

Iron–manganese-doped sulfated zirconia nanoparticles with both Lewis and Brønsted acidic sites were prepared by a hydrothermal impregnation method followed by calcination at 650°C for 5 hours, and their cytotoxicity properties against cancer cell lines were determined. The characterization was carried out using X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, Brauner–Emmett–Teller (BET) surface area measurements, X-ray fluorescence, X-ray photoelectron spectroscopy, zeta size potential, and transmission electron microscopy (TEM). The cytotoxicity of iron–manganese-doped sulfated zirconia nanoparticles was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays against three human cancer cell lines (breast cancer MDA-MB231 cells, colon carcinoma HT29 cells, and hepatocellular carcinoma HepG2 cells) and two normal human cell lines (normal hepatocyte Chang cells and normal human umbilical vein endothelial cells [HUVECs]). The results suggest for the first time that iron–manganese-doped sulfated zirconia nanoparticles are cytotoxic to MDA-MB231 and HepG2 cancer cells but have less toxicity to HT29 and normal cells at concentrations from 7.8 μg/mL to 500 μg/mL. The morphology of the treated cells was also studied, and the results supported those from the cytotoxicity study in that the nanoparticle-treated HepG2 and MDA-MB231 cells had more dramatic changes in cell morphology than the HT29 cells. In this manner, this study provides the first evidence that iron–manganese-doped sulfated zirconia nanoparticles should be further studied for a wide range of cancer applications without detrimental effects on healthy cell functions. PMID:26425082

Alterations of sodium and potassium channels of RGCs in RCS rat with the development of retinal degeneration.

PubMed

Chen, Zhongshan; Song, Yanping; Yao, Junping; Weng, Chuanhuang; Yin, Zheng Qin

2013-11-01

All know that retinitis pigmentosa (RP) is a group of hereditary retinal degenerative diseases characterized by progressive dysfunction of photoreceptors and associated with progressive cells loss; nevertheless, little is known about how rods and cones loss affects the surviving inner retinal neurons and networks. Retinal ganglion cells (RGCs) process and convey visual information from retina to visual centers in the brain. The healthy various ion channels determine the normal reception and projection of visual signals from RGCs. Previous work on the Royal College of Surgeons (RCS) rat, as a kind of classical RP animal model, indicated that, at late stages of retinal degeneration in RCS rat, RGCs were also morphologically and functionally affected. Here, retrograde labeling for RGCs with Fluorogold was performed to investigate the distribution, density, and morphological changes of RGCs during retinal degeneration. Then, patch clamp recording, western blot, and immunofluorescence staining were performed to study the channels of sodium and potassium properties of RGCs, so as to explore the molecular and proteinic basis for understanding the alterations of RGCs membrane properties and firing functions. We found that the resting membrane potential, input resistance, and capacitance of RGCs changed significantly at the late stage of retinal degeneration. Action potential could not be evoked in a part of RGCs. Inward sodium current and outward potassium current recording showed that sodium current was impaired severely but only slightly in potassium current. Expressions of sodium channel protein were impaired dramatically at the late stage of retinal degeneration. The results suggested that the density of RGCs decreased, process ramification impaired, and sodium ion channel proteins destructed, which led to the impairment of electrophysiological functions of RGCs and eventually resulted in the loss of visual function.

Geomorphic effects, flood power, and channel competence of a catastrophic flood in confined and unconfined reaches of the upper Lockyer valley, southeast Queensland, Australia

NASA Astrophysics Data System (ADS)

Thompson, Chris; Croke, Jacky

2013-09-01

Flooding is a persistent natural hazard, and even modest changes in future climate are believed to lead to large increases in flood magnitude. Previous studies of extreme floods have reported a range of geomorphic responses from negligible change to catastrophic channel change. This paper provides an assessment of the geomorphic effects of a rare, high magnitude event that occurred in the Lockyer valley, southeast Queensland in January 2011. The average return interval of the resulting flood was ~ 2000 years in the upper catchment and decreased to ~ 30 years downstream. A multitemporal LiDAR-derived DEM of Difference (DoD) is used to quantify morphological change in two study reaches with contrasting valley settings (confined and unconfined). Differences in geomorphic response between reaches are examined in the context of changes in flood power, channel competence and degree of valley confinement using a combination of one-dimensional (1-D) and two-dimensional (2-D) hydraulic modelling. Flood power peaked at 9800 W m- 2 along the confined reach and was 2-3 times lower along the unconfined reach. Results from the DoD confirm that the confined reach was net erosional, exporting ~ 287,000 m3 of sediment whilst the unconfined reach was net depositional gaining ~ 209,000 m3 of sediment, 70% of the amount exported from the upstream, confined reach. The major sources of eroded sediment in the confined reach were within channel benches and macrochannel banks resulting in a significant increase of channel width. In the unconfined reach, the benches and floodplains were the major loci for deposition, whilst the inner channel exhibited minor width increases. The presence of high stream power values, and resultant high erosion rates, within the confined reach is a function of the higher energy gradient of the steeper channel that is associated with knickpoint development. Dramatic differences in geomorphic responses were observed between the two adjacent reaches of contrasting valley configuration. The confined reach experienced large-scale erosion and reorganisation of the channel morphology that resulted in significantly different areal representations of the five geomorphic features classified in this study.

The bald and the beautiful: hairlessness in domestic dog breeds.

PubMed

Parker, Heidi G; Harris, Alexander; Dreger, Dayna L; Davis, Brian W; Ostrander, Elaine A

2017-02-05

An extraordinary amount of genomic variation is contained within the chromosomes of domestic dogs, manifesting as dramatic differences in morphology, behaviour and disease susceptibility. Morphology, in particular, has been a topic of enormous interest as biologists struggle to understand the small window of dog domestication from wolves, and the division of dogs into pure breeding, closed populations termed breeds. Many traits related to morphology, including body size, leg length and skull shape, have been under selection as part of the standard descriptions for the nearly 400 breeds recognized worldwide. Just as important, however, are the minor traits that have undergone selection by fanciers and breeders to define dogs of a particular appearance, such as tail length, ear position, back arch and variation in fur (pelage) growth patterns. In this paper, we both review and present new data for traits associated with pelage including fur length, curl, growth, shedding and even the presence or absence of fur. Finally, we report the discovery of a new gene associated with the absence of coat in the American Hairless Terrier breed.This article is part of the themed issue 'Evo-devo in the genomics era, and the origins of morphological diversity'. © 2016 The Authors.

An updated systematic review on the possible effect of nonylphenol on male fertility.

PubMed

Noorimotlagh, Zahra; Haghighi, Neemat Jaafarzadeh; Ahmadimoghadam, Mehdi; Rahim, Fakher

2017-02-01

Diverse industries like detergents, resins and polymers, hair dyes, intravaginal spermicides, and pesticides produce endocrine disruptor (ED)-containing wastewaters that have hazardous effects on the environment and public health. Nonylphenol (NP) is a chemical substance that consists of a phenolic group and an attached lipophilic linear nonyl chain. NP has weak estrogenic activity and affects estrogen receptor (ER), as well as induces male infertility via a negative impact on spermatogenesis and sperm quality. The aim of this study was to comprehensively review all available literature about the side effects of NP on the male genital system. We systematically searched Scopus and PubMed using MeSH terms that include "Organic Chemicals," "Infertility," "Infertility, Male," "Nonylphenol", ("Infertility, Male"[Mesh]) OR "Nonylphenol" [Supplementary Concept]) OR "Prostate"[Mesh]) OR "Spermatozoa"[Mesh]) OR "Sertoli Cells"[Mesh]) OR "Leydig Cells"[Mesh] OR "Male accessory gland" OR "Epididym" OR "Reproductive toxicity"), and all other possible combinations from January 1, 1970, to September 15, 2016, with language limit. The initial search identified 117,742 potentially eligible studies, of which 33 met the established inclusion criteria and were included in the analysis. Thirty-three selected studies include animal model (n = 18), cell line (n = 15), human model (n = 1), morphology (n = 13), sperm quality (n = 17), and toxicity (n = 14). This review highlighted the evidence for the ED effect of NP that acts through interference with ER, discussing male reproductive tract perturbations. We critically discuss the available evidence on the effect of NP on sperm quality (such as motility, viability, sperm count, and sperm concentration), dramatic morphological changes (such as change of weights of testes and epididymis), and biochemical changes related to oxidative stress in testes. Finally, it is important to take caution with the continued use of NP that disrupts male reproductive health.

Structural and Functional Maturation of Cardiomyocytes Derived from Human Pluripotent Stem Cells

PubMed Central

Lundy, Scott D.; Zhu, Wei-Zhong

2013-01-01

Despite preclinical studies demonstrating the functional benefit of transplanting human pluripotent stem cell-derived cardiomyocytes (PSC-CMs) into damaged myocardium, the ability of these immature cells to adopt a more adult-like cardiomyocyte (CM) phenotype remains uncertain. To address this issue, we tested the hypothesis that prolonged in vitro culture of human embryonic stem cell (hESC)- and human induced pluripotent stem cell (hiPSC)-derived CMs would result in the maturation of their structural and contractile properties to a more adult-like phenotype. Compared to their early-stage counterparts (PSC-CMs after 20–40 days of in vitro differentiation and culture), late-stage hESC-CMs and hiPSC-CMs (80–120 days) showed dramatic differences in morphology, including increased cell size and anisotropy, greater myofibril density and alignment, sarcomeres visible by bright-field microscopy, and a 10-fold increase in the fraction of multinucleated CMs. Ultrastructural analysis confirmed improvements in the myofibrillar density, alignment, and morphology. We measured the contractile performance of late-stage hESC-CMs and hiPSC-CMs and noted a doubling in shortening magnitude with slowed contraction kinetics compared to the early-stage cells. We then examined changes in the calcium-handling properties of these matured CMs and found an increase in calcium release and reuptake rates with no change in the maximum amplitude. Finally, we performed electrophysiological assessments in hESC-CMs and found that late-stage myocytes have hyperpolarized maximum diastolic potentials, increased action potential amplitudes, and faster upstroke velocities. To correlate these functional changes with gene expression, we performed qPCR and found a robust induction of the key cardiac structural markers, including β-myosin heavy chain and connexin-43, in late-stage hESC-CMs and hiPSC-CMs. These findings suggest that PSC-CMs are capable of slowly maturing to more closely resemble the phenotype of adult CMs and may eventually possess the potential to regenerate the lost myocardium with robust de novo force-producing tissue. PMID:23461462

Linking hydrology, morphodynamics and ecology to assess the restoration potential of the heavily regulated Sarca River, NE Italy

NASA Astrophysics Data System (ADS)

Carolli, Mauro; Zolezzi, Guido; Pellegrini, Stefano; Gelmini, Francesca; Deriu, Micaela

2017-04-01

We develop an integrated eco-hydro-morphological quantitative investigation of the upper course of the Alpine Sarca River (NE Italy), for the purpose of assessing its potential in terms of environmental restoration. The Sarca River has been subject to heavy exploitation for hydropower production since the 1950s through a complex infrastructural system. As for many regulated Alpine rivers, increasing local interest has recently been developing to design and implement river restoration measures to improve the environmental conditions and ecosystem services that the river can provide. The aim of the work is to develop and apply a quantitative approach for a preliminary assessment of the successful potential of different river restoration options in the light of the recent eco-hydro-morphological dynamics of the Sarca river system at the catchment scale. The proposed analysis consists of three main steps: (1) detection of the main drivers of flow and sediment supply regimes alteration and characterization of such alteration; (2) a quantification of the effects of those alterations on geomorphic processes and fish habitat conditions; (3) the analysis of the restoration potential in the light of the results of the previous assessment. The analysis is tailored to the existing data availability, which is relatively high as for most river systems of comparable size in Europe, but not as much as in the case of a targeted research project, thus providing a representative case for many other regulated river catchments. Hydrological alteration is quantified by comparing recent (20 years) streamflow time series with a reconstructed series of analogous length, using a hydrological model that has been run excluding any man-made water abstraction, release and artificial reservoirs. upstream and downstream a large dam in the middle course of the river. By choosing the adult marble trout as target (endemic) fish species, effects of the alterations on the temporal and spatial habitat suitability have been assessed by applying a hydraulic-habitat method combined with the streamflow time series. Geomorphological trajectories of the last decades have been reconstructed through the analysis of aerial photos, and the geomorphic effects of flow regime alteration have been assessed in terms of the changes in frequency and duration of gravel-transporting flood events. Results indicate hydropower as one of the drivers of hydro-morphological alteration, with widespread torrent control works in the catchment playing a relevant role in reducing sediment supply. Recent changes in flow management related to the imposition of a Minimum Environmental Flow correspond to significant increase in the continuous duration of suitable habitat events, despite representing only a first step towards a dynamic ecological flow regime. While floods able to drive morphological changes still occurred after regulation, their frequency and duration have dramatically decreased, contributing to channel narrowing and morphological simplification. Overall, the analysis suggests that: (i) morphological river restoration aimed at restoring self-formed morphodynamics can only be effective if designed together with a dynamic geomorphic flow regime, and (ii) dynamic ecological flows should designed with a twofold objective of improving habitat and spawning sites conditions together with recreational uses of the river.

Psychosocial aspects of women's lives: work, family, and life cycle issues.

PubMed

Shrier, Diane K

2003-09-01

Over the past century and continuing to evolve into the twenty-first century, there have been dramatic changes in work and personal/family lives within the United States. These changes, though strongly affecting men and children, have impacted most dramatically on women's lives, particularly white, middle-class women. Psychiatrists and other mental health clinicians need to be aware of the scope and nature of these changes and to recognize that their own personal experiences and values might differ from those of women of different generations as well as different socioeconomic and cultural backgrounds.

Tongue-driven sonar beam steering by a lingual-echolocating fruit bat

PubMed Central

Falk, Benjamin; Chiu, Chen; Krishnan, Anand; Arbour, Jessica H.; Moss, Cynthia F.

2017-01-01

Animals enhance sensory acquisition from a specific direction by movements of head, ears, or eyes. As active sensing animals, echolocating bats also aim their directional sonar beam to selectively “illuminate” a confined volume of space, facilitating efficient information processing by reducing echo interference and clutter. Such sonar beam control is generally achieved by head movements or shape changes of the sound-emitting mouth or nose. However, lingual-echolocating Egyptian fruit bats, Rousettus aegyptiacus, which produce sound by clicking their tongue, can dramatically change beam direction at very short temporal intervals without visible morphological changes. The mechanism supporting this capability has remained a mystery. Here, we measured signals from free-flying Egyptian fruit bats and discovered a systematic angular sweep of beam focus across increasing frequency. This unusual signal structure has not been observed in other animals and cannot be explained by the conventional and widely-used “piston model” that describes the emission pattern of other bat species. Through modeling, we show that the observed beam features can be captured by an array of tongue-driven sound sources located along the side of the mouth, and that the sonar beam direction can be steered parsimoniously by inducing changes to the pattern of phase differences through moving tongue location. The effects are broadly similar to those found in a phased array—an engineering design widely found in human-made sonar systems that enables beam direction changes without changes in the physical transducer assembly. Our study reveals an intriguing parallel between biology and human engineering in solving problems in fundamentally similar ways. PMID:29244805

Tongue-driven sonar beam steering by a lingual-echolocating fruit bat.

PubMed

Lee, Wu-Jung; Falk, Benjamin; Chiu, Chen; Krishnan, Anand; Arbour, Jessica H; Moss, Cynthia F

2017-12-01

Animals enhance sensory acquisition from a specific direction by movements of head, ears, or eyes. As active sensing animals, echolocating bats also aim their directional sonar beam to selectively "illuminate" a confined volume of space, facilitating efficient information processing by reducing echo interference and clutter. Such sonar beam control is generally achieved by head movements or shape changes of the sound-emitting mouth or nose. However, lingual-echolocating Egyptian fruit bats, Rousettus aegyptiacus, which produce sound by clicking their tongue, can dramatically change beam direction at very short temporal intervals without visible morphological changes. The mechanism supporting this capability has remained a mystery. Here, we measured signals from free-flying Egyptian fruit bats and discovered a systematic angular sweep of beam focus across increasing frequency. This unusual signal structure has not been observed in other animals and cannot be explained by the conventional and widely-used "piston model" that describes the emission pattern of other bat species. Through modeling, we show that the observed beam features can be captured by an array of tongue-driven sound sources located along the side of the mouth, and that the sonar beam direction can be steered parsimoniously by inducing changes to the pattern of phase differences through moving tongue location. The effects are broadly similar to those found in a phased array-an engineering design widely found in human-made sonar systems that enables beam direction changes without changes in the physical transducer assembly. Our study reveals an intriguing parallel between biology and human engineering in solving problems in fundamentally similar ways.

[Grape seed extract induces morphological changes of prostate cancer PC-3 cells].

PubMed

Shang, Xue-Jun; Yin, Hong-Lin; Ge, Jing-Ping; Sun, Yi; Teng, Wen-Hui; Huang, Yu-Feng

2008-12-01

To observe the morphological changes of prostate cancer PC-3 cells induced by grape seed extract (GSE). PC-3 cells were incubated with different concentrations of GSE (100, 200 and 300 microg/ml) for 24, 48 and 72 hours, and then observed for morphological changes by invert microscopy, HE staining and transmission electron microscopy. The incubated PC-3 cells appeared round, small, wrinkled and broken under the invert microscope and exhibited the classical morphological characteristics of cell death under the electron microscope, including cell atrophy, increased vacuoles, crumpled nuclear membrane, and chromosome aggregation. GSE can cause morphological changes and induce necrosis and apoptosis of PC-3 cells.

Higher Education Affordability: Two Approaches

ERIC Educational Resources Information Center

DiSalvo, Steven R.

2017-01-01

There are two initiatives that can dramatically change the way college pricing and student debt are being handled under the current system. Both are commonsense solutions that would, if accepted, dramatically help students, graduates and families burdened by the cost of tuition and the loans they take to earn their degrees. First, income-based…

The health care industry: in evolution or revolution?

PubMed

Cleverley, W O

1999-01-01

The health care industry has experienced dramatic changes during the last 25 years and will likely undergo even more dramatic changes in the next 25 years. Many firms in the health care industry will thrive just as many firms have thrived during the last 25 years. The ultimate key to success will be management and their attention to the basics of good business management. Management has always been the key ingredient and will continue to be the most critical success factor.

Strong signatures of selection in the domestic pig genome.

PubMed

Rubin, Carl-Johan; Megens, Hendrik-Jan; Martinez Barrio, Alvaro; Maqbool, Khurram; Sayyab, Shumaila; Schwochow, Doreen; Wang, Chao; Carlborg, Örjan; Jern, Patric; Jørgensen, Claus B; Archibald, Alan L; Fredholm, Merete; Groenen, Martien A M; Andersson, Leif

2012-11-27

Domestication of wild boar (Sus scrofa) and subsequent selection have resulted in dramatic phenotypic changes in domestic pigs for a number of traits, including behavior, body composition, reproduction, and coat color. Here we have used whole-genome resequencing to reveal some of the loci that underlie phenotypic evolution in European domestic pigs. Selective sweep analyses revealed strong signatures of selection at three loci harboring quantitative trait loci that explain a considerable part of one of the most characteristic morphological changes in the domestic pig--the elongation of the back and an increased number of vertebrae. The three loci were associated with the NR6A1, PLAG1, and LCORL genes. The latter two have repeatedly been associated with loci controlling stature in other domestic animals and in humans. Most European domestic pigs are homozygous for the same haplotype at these three loci. We found an excess of derived nonsynonymous substitutions in domestic pigs, most likely reflecting both positive selection and relaxed purifying selection after domestication. Our analysis of structural variation revealed four duplications at the KIT locus that were exclusively present in white or white-spotted pigs, carrying the Dominant white, Patch, or Belt alleles. This discovery illustrates how structural changes have contributed to rapid phenotypic evolution in domestic animals and how alleles in domestic animals may evolve by the accumulation of multiple causative mutations as a response to strong directional selection.

Strong signatures of selection in the domestic pig genome

PubMed Central

Rubin, Carl-Johan; Megens, Hendrik-Jan; Barrio, Alvaro Martinez; Maqbool, Khurram; Sayyab, Shumaila; Schwochow, Doreen; Wang, Chao; Carlborg, Örjan; Jern, Patric; Jørgensen, Claus B.; Archibald, Alan L.; Fredholm, Merete; Groenen, Martien A. M.; Andersson, Leif

2012-01-01

Domestication of wild boar (Sus scrofa) and subsequent selection have resulted in dramatic phenotypic changes in domestic pigs for a number of traits, including behavior, body composition, reproduction, and coat color. Here we have used whole-genome resequencing to reveal some of the loci that underlie phenotypic evolution in European domestic pigs. Selective sweep analyses revealed strong signatures of selection at three loci harboring quantitative trait loci that explain a considerable part of one of the most characteristic morphological changes in the domestic pig—the elongation of the back and an increased number of vertebrae. The three loci were associated with the NR6A1, PLAG1, and LCORL genes. The latter two have repeatedly been associated with loci controlling stature in other domestic animals and in humans. Most European domestic pigs are homozygous for the same haplotype at these three loci. We found an excess of derived nonsynonymous substitutions in domestic pigs, most likely reflecting both positive selection and relaxed purifying selection after domestication. Our analysis of structural variation revealed four duplications at the KIT locus that were exclusively present in white or white-spotted pigs, carrying the Dominant white, Patch, or Belt alleles. This discovery illustrates how structural changes have contributed to rapid phenotypic evolution in domestic animals and how alleles in domestic animals may evolve by the accumulation of multiple causative mutations as a response to strong directional selection. PMID:23151514

Dramatic change of the recurrence time and outburst parameters of the intermediate polar GK Persei

NASA Astrophysics Data System (ADS)

Šimon, V.

2002-02-01

This analysis has shown that the intermediate polar GK Per experienced a very striking evolution. Its outbursts became wider and brighter in the last five decades. These changes were accompanied by striking variations of the recurrence time T_C, from 385 days within the years 1948-1967 to 890 days in 1970. Nowadays, T_C displays a strong trend of linear increase. Decrease of irradiation of the disk by the WD, combined with the decrease of viscosity, offers a plausible explanation. It is argued that variations of the mass transfer rate are unlikely to play a major role. The morphology of the outburst light curves in the optical and the X-ray region is also studied. The decay branch in the optical remains remarkably similar for all the events while the largest changes of the light curve occur in the rising branch. This can be explained if the thermal instability may start at different distances from the disk center. The quiescent level of brightness does not display any secular trend in recent decades but a wave on the time scale of about 30 years with the full amplitude of 0.3 m_v, probably due to activity of the cool star, is detected. This research has made use of the AFOEV database, operated at CDS, France, and the observations provided by the ASM/RXTE team.

Oxygen depletion speeds and simplifies diffusion in HeLa cells.

PubMed

Edwald, Elin; Stone, Matthew B; Gray, Erin M; Wu, Jing; Veatch, Sarah L

2014-10-21

Many cell types undergo a hypoxic response in the presence of low oxygen, which can lead to transcriptional, metabolic, and structural changes within the cell. Many biophysical studies to probe the localization and dynamics of single fluorescently labeled molecules in live cells either require or benefit from low-oxygen conditions. In this study, we examine how low-oxygen conditions alter the mobility of a series of plasma membrane proteins with a range of anchoring motifs in HeLa cells at 37°C. Under high-oxygen conditions, diffusion of all proteins is heterogeneous and confined. When oxygen is reduced with an enzymatic oxygen-scavenging system for ≥ 15 min, diffusion rates increase by > 2-fold, motion becomes unconfined on the timescales and distance scales investigated, and distributions of diffusion coefficients are remarkably consistent with those expected from Brownian motion. More subtle changes in protein mobility are observed in several other laboratory cell lines examined under both high- and low-oxygen conditions. Morphological changes and actin remodeling are observed in HeLa cells placed in a low-oxygen environment for 30 min, but changes are less apparent in the other cell types investigated. This suggests that changes in actin structure are responsible for increased diffusion in hypoxic HeLa cells, although superresolution localization measurements in chemically fixed cells indicate that membrane proteins do not colocalize with F-actin under either experimental condition. These studies emphasize the importance of controls in single-molecule imaging measurements, and indicate that acute response to low oxygen in HeLa cells leads to dramatic changes in plasma membrane structure. It is possible that these changes are either a cause or consequence of phenotypic changes in solid tumor cells associated with increased drug resistance and malignancy.

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

An examination of changes in maternal neuroimmune function during pregnancy and the postpartum period.

PubMed

Sherer, Morgan L; Posillico, Caitlin K; Schwarz, Jaclyn M

2017-11-01

There is strong evidence that the immune system changes dramatically during pregnancy in order to prevent the developing fetus from being "attacked" by the maternal immune system. Due to these alterations in peripheral immune function, many women that suffer from autoimmune disorders actually find significant relief from their symptoms throughout pregnancy; however, these changes can also leave the mother more susceptible to infections that would otherwise be mitigated by the inflammatory response (Robinson and Klein, 2012). Only one other study has looked at changes in microglial number and morphology during pregnancy and the postpartum period (Haim et al., 2016), but no one has yet examined the neuroimmune response following an immune challenge during this time. Therefore, in this study, we investigated the impact of an immune challenge during various time-points throughout pregnancy and the postpartum period on the expression of immune molecules in the brain of the mother and fetus. Our results indicate that similar to the peripheral immune suppression measured during pregnancy, we also see significant suppression of the immune response in the maternal brain, particularly during late gestation. In contrast to the peripheral immune system, immune modulation in the maternal brain extends moderately into the postpartum period. Additionally, we found that the fetal immune response in the brain and placenta is also suppressed just before parturition, suggesting that cytokine production in the fetus and placenta are mirroring the peripheral cytokine response of the mother. Copyright © 2017 Elsevier Inc. All rights reserved.

Computational modeling indicates that surface pressure can be reliably conveyed to tactile receptors even amidst changes in skin mechanics

PubMed Central

Wang, Yuxiang; Baba, Yoshichika; Lumpkin, Ellen A.

2016-01-01

Distinct patterns in neuronal firing are observed between classes of cutaneous afferents. Such differences may be attributed to end-organ morphology, distinct ion-channel complements, and skin microstructure, among other factors. Even for just the slowly adapting type I afferent, the skin's mechanics for a particular specimen might impact the afferent's firing properties, especially given the thickness and elasticity of skin can change dramatically over just days. Here, we show computationally that the skin can reliably convey indentation magnitude, rate, and spatial geometry to the locations of tactile receptors even amid changes in skin's structure. Using finite element analysis and neural dynamics models, we considered the skin properties of six mice that span a representative cohort. Modeling the propagation of the surface stimulus to the interior of the skin demonstrated that there can be large variance in stresses and strains near the locations of tactile receptors, which can lead to large variance in static firing rate. However, variance is significantly reduced when the stimulus tip is controlled by surface pressure and compressive stress is measured near the end organs. This particular transformation affords the least variability in predicted firing rates compared with others derived from displacement, force, strain energy density, or compressive strain. Amid changing skin mechanics, stimulus control by surface pressure may be more naturalistic and optimal and underlie how animals actively explore the tactile environment. PMID:27098029

Arctic Sea Ice Structure and Texture over Four Decades Using Landsat Archive Data

NASA Astrophysics Data System (ADS)

Doulgeris, A. P.; Scambos, T.; Tiampo, K. F.

2017-12-01

Arctic sea ice cover is a sensitive indicator of Arctic climate change, and has shown dramatic changes in recent decades, having thinned by 70% ( 3.5 m to 1.2 m between 1980 and 2015). Age distribution of the ice has changed in a similar fashion, with over 90% of the ice older than 5 winters now lost relative to 1985. To date, most of the data have been based on the continuous passive microwave record that began in 1978, which has 25 km grid resolution, or on SAR imagery with somewhat less frequent, less continuous observations. Landsat image data exist for the Arctic sea ice region north of Alaska and the MacKenzie River Delta area in Canada, the Canadian Archipelago, and Baffin Bay, extending back over 40 years. Resolution of the earliest Landsat MSS data is 56-70 m per pixel, and after 1984 many additional images at 30 m resolution are available. This 40+ year time period is used to investigate long-term changes in sea ice properties, such as comparing image-based snapshots with the trend in seasonal extents today, as well as more novel properties like sea ice roughness, lead structure and texture. The proposed study will initially investigate Landsat image analysis techniques to extract quantitative measures of ice roughness, lead fraction and perhaps morphological measures like lead linearity (which potentially indicate strength and compression history within the ice), and to explore these measures over the 40+ year time frame.

Oblique angle deposition-induced anisotropy in Co2FeAl films

NASA Astrophysics Data System (ADS)

Zhou, W.; Brock, J.; Khan, M.; Eid, K. F.

2018-06-01

A series of Co2FeAl Heusler alloy films, fabricated on Si/SiO2 substrates by magnetron sputtering-oblique angle deposition technique, have been investigated by magnetization and transport measurements. The morphology and magnetic anisotropy of the films strongly depended on the deposition angle. While the film deposited at zero degree (i.e. normal incidence) did not show any anisotropy, the films deposited at higher angles showed unusually strong in-plane anisotropy that increased with deposition angle. The enhanced anisotropy was well-reflected in the direction-dependent magnetization and the coercivity of the films that increased dramatically from 30 Oe to 490 Oe. In a similar vein, the electrical resistivity of the films also increased drastically, especially for deposition angles larger than 60°. These anisotropic effects and their relation to the morphology of the films are discussed.

Morphological change in cranial shape following the transition to agriculture across western Eurasia.

PubMed

Cheronet, Olivia; Finarelli, John A; Pinhasi, Ron

2016-09-13

The Neolithic transition brought about fundamental social, dietary and behavioural changes in human populations, which, in turn, impacted skeletal morphology. Crania are shaped through diverse genetic, ontogenetic and environmental factors, reflecting various elements of an individual's life. To determine the transition's effect on cranial morphology, we investigated its potential impact on the face and vault, two elements potentially responding to different influences. Three datasets from geographically distant regions (Ukraine, Iberia, and the Levant plus Anatolia) were analysed. Craniometric measurements were used to compare the morphology of pre-transition populations with that of agricultural populations. The Neolithic transition corresponds to a statistically significant increase only in cranial breadth of the Ukrainian vaults, while facial morphology shows no consistent transformations, despite expected changes related to the modification of masticatory behaviour. The broadening of Ukrainian vaults may be attributable to dietary and/or social changes. However, the lack of change observed in the other geographical regions and the lack of consistent change in facial morphology are surprising. Although the transition from foraging to farming is a process that took place repeatedly across the globe, different characteristics of transitions seem responsible for idiosyncratic responses in cranial morphology.

Differential Responses to Woodland Character and Landscape Context by Cryptic Bats in Urban Environments

PubMed Central

Lintott, Paul R.; Bunnefeld, Nils; Minderman, Jeroen; Fuentes-Montemayor, Elisa; Mayhew, Rebekah J.; Olley, Lena; Park, Kirsty J.

2015-01-01

Urbanisation is one of the most dramatic forms of land use change which relatively few species can adapt to. Determining how and why species respond differently to urban habitats is important in predicting future biodiversity loss as urban areas rapidly expand. Understanding how morphological or behavioural traits can influence species adaptability to the built environment may enable us to improve the effectiveness of conservation efforts. Although many bat species are able to exploit human resources, bat species richness generally declines with increasing urbanisation and there is considerable variation in the responses of different bat species to urbanisation. Here, we use acoustic recordings from two cryptic, and largely sympatric European bat species to assess differential responses in their use of fragmented urban woodland and the surrounding urban matrix. There was a high probability of P. pygmaeus activity relative to P. pipistrellus in woodlands with low clutter and understory cover which were surrounded by low levels of built environment. Additionally, the probability of recording P. pygmaeus relative to P. pipistrellus was considerably higher in urban woodland interior or edge habitat in contrast to urban grey or non-wooded green space. These results show differential habitat use occurring between two morphologically similar species; whilst the underlying mechanism for this partitioning is unknown it may be driven by competition avoidance over foraging resources. Their differing response to urbanisation indicates the difficulties involved when attempting to assess how adaptable a species is to urbanisation for conservation purposes. PMID:25978034

Effects of Excess Fluoride and Iodide on Thyroid Function and Morphology.

PubMed

Jiang, Yaqiu; Guo, Xiujuan; Sun, Qiuyan; Shan, Zhongyan; Teng, Weiping

2016-04-01

Exposure to high levels of iodide in Cangzhou, Shandong Province, China has been associated with increased incidence of thyroid disease; however, whether fluoride can affect the thyroid remains controversial. To investigate the effects of excess fluoride, we evaluated thyroid gland structure and function in rats exposed to fluoride and iodide, either alone or in combination. Five-week-old Wistar rats (n = 160 total) were randomly divided into eight groups: three groups that were given excess fluoride (15, 30, or 60 ppm F); one group given excess iodide (1200 μg/L I); three groups given excess iodide plus fluoride (1200 μg/L I plus 15, 30, or 60 ppm F); and one control group. The serum concentrations of the thyroid hormones TT3 and TT4 on day 150 were significantly reduced for certain fluoride groups; however, no significant differences were observed in concentrations for the pituitary hormone TSH among any groups. Hematoxylin and eosin staining revealed that iodide causes an increase in the areas of the colloid lumens and a decrease in the diameters of epithelial cells and nuclei; however, fluoride causes an increase in nuclear diameters. The damage to follicular epithelial cells upon fluoride or iodide treatment was easily observed by transmission electron microscopy, but the effects were most dramatic upon treatment with both fluoride and iodide. These results suggest that iodide causes the most damage but that fluoride can promote specific changes in the function and morphology of the thyroid, either alone or in combination with iodide.

Differential responses to woodland character and landscape context by cryptic bats in urban environments.

PubMed

Lintott, Paul R; Bunnefeld, Nils; Minderman, Jeroen; Fuentes-Montemayor, Elisa; Mayhew, Rebekah J; Olley, Lena; Park, Kirsty J

2015-01-01

Urbanisation is one of the most dramatic forms of land use change which relatively few species can adapt to. Determining how and why species respond differently to urban habitats is important in predicting future biodiversity loss as urban areas rapidly expand. Understanding how morphological or behavioural traits can influence species adaptability to the built environment may enable us to improve the effectiveness of conservation efforts. Although many bat species are able to exploit human resources, bat species richness generally declines with increasing urbanisation and there is considerable variation in the responses of different bat species to urbanisation. Here, we use acoustic recordings from two cryptic, and largely sympatric European bat species to assess differential responses in their use of fragmented urban woodland and the surrounding urban matrix. There was a high probability of P. pygmaeus activity relative to P. pipistrellus in woodlands with low clutter and understory cover which were surrounded by low levels of built environment. Additionally, the probability of recording P. pygmaeus relative to P. pipistrellus was considerably higher in urban woodland interior or edge habitat in contrast to urban grey or non-wooded green space. These results show differential habitat use occurring between two morphologically similar species; whilst the underlying mechanism for this partitioning is unknown it may be driven by competition avoidance over foraging resources. Their differing response to urbanisation indicates the difficulties involved when attempting to assess how adaptable a species is to urbanisation for conservation purposes.

Green revolution trees: semidwarfism transgenes modify gibberellins, promote root growth, enhance morphological diversity, and reduce competitiveness in hybrid poplar.

PubMed

Elias, Ani A; Busov, Victor B; Kosola, Kevin R; Ma, Cathleen; Etherington, Elizabeth; Shevchenko, Olga; Gandhi, Harish; Pearce, David W; Rood, Stewart B; Strauss, Steven H

2012-10-01

Semidwarfism has been used extensively in row crops and horticulture to promote yield, reduce lodging, and improve harvest index, and it might have similar benefits for trees for short-rotation forestry or energy plantations, reclamation, phytoremediation, or other applications. We studied the effects of the dominant semidwarfism transgenes GA Insensitive (GAI) and Repressor of GAI-Like, which affect gibberellin (GA) action, and the GA catabolic gene, GA 2-oxidase, in nursery beds and in 2-year-old high-density stands of hybrid poplar (Populus tremula × Populus alba). Twenty-nine traits were analyzed, including measures of growth, morphology, and physiology. Endogenous GA levels were modified in most transgenic events; GA(20) and GA(8), in particular, had strong inverse associations with tree height. Nearly all measured traits varied significantly among genotypes, and several traits interacted with planting density, including aboveground biomass, root-shoot ratio, root fraction, branch angle, and crown depth. Semidwarfism promoted biomass allocation to roots over shoots and substantially increased rooting efficiency with most genes tested. The increased root proportion and increased leaf chlorophyll levels were associated with changes in leaf carbon isotope discrimination, indicating altered water use efficiency. Semidwarf trees had dramatically reduced growth when in direct competition with wild-type trees, supporting the hypothesis that semidwarfism genes could be effective tools to mitigate the spread of exotic, hybrid, and transgenic plants in wild and feral populations.

Green Revolution Trees: Semidwarfism Transgenes Modify Gibberellins, Promote Root Growth, Enhance Morphological Diversity, and Reduce Competitiveness in Hybrid Poplar1[C][W][OA

PubMed Central

Elias, Ani A.; Busov, Victor B.; Kosola, Kevin R.; Ma, Cathleen; Etherington, Elizabeth; Shevchenko, Olga; Gandhi, Harish; Pearce, David W.; Rood, Stewart B.; Strauss, Steven H.

2012-01-01

Semidwarfism has been used extensively in row crops and horticulture to promote yield, reduce lodging, and improve harvest index, and it might have similar benefits for trees for short-rotation forestry or energy plantations, reclamation, phytoremediation, or other applications. We studied the effects of the dominant semidwarfism transgenes GA Insensitive (GAI) and Repressor of GAI-Like, which affect gibberellin (GA) action, and the GA catabolic gene, GA 2-oxidase, in nursery beds and in 2-year-old high-density stands of hybrid poplar (Populus tremula × Populus alba). Twenty-nine traits were analyzed, including measures of growth, morphology, and physiology. Endogenous GA levels were modified in most transgenic events; GA20 and GA8, in particular, had strong inverse associations with tree height. Nearly all measured traits varied significantly among genotypes, and several traits interacted with planting density, including aboveground biomass, root-shoot ratio, root fraction, branch angle, and crown depth. Semidwarfism promoted biomass allocation to roots over shoots and substantially increased rooting efficiency with most genes tested. The increased root proportion and increased leaf chlorophyll levels were associated with changes in leaf carbon isotope discrimination, indicating altered water use efficiency. Semidwarf trees had dramatically reduced growth when in direct competition with wild-type trees, supporting the hypothesis that semidwarfism genes could be effective tools to mitigate the spread of exotic, hybrid, and transgenic plants in wild and feral populations. PMID:22904164

Fusion, rupture, and degeneration: the fate of in vivo-labelled PSVs in developing barley endosperm.

PubMed

Ibl, Verena; Kapusi, Eszter; Arcalis, Elsa; Kawagoe, Yasushi; Stoger, Eva

2014-07-01

Cereal endosperm is a highly differentiated tissue containing specialized organelles for the accumulation of storage proteins. The endosperm of barley contains hordeins, which are ultimately deposited within protein storage vacuoles (PSVs). These organelles have been characterized predominantly by the histochemical analysis of fixed immature tissue samples. However, little is known about the fate of PSVs during barley endosperm development, and in vivo imaging has not been attempted in order to gain further insight. In this report, young seeds were followed through development to characterize the dynamic morphology of PSVs from aleurone, subaleurone, and central starchy endosperm cells. TIP3-GFP was used as a PSV membrane marker and several fluorescent tracers were used to identify membranes and monitor endomembrane organelles in real time. Whereas the spherical appearance of strongly labelled TIP3-GFP PSVs in the aleurone remained constant, those in the subaleurone and central starchy endosperm underwent substantial morphological changes. Fusion and rupture events were observed in the subaleurone, and internal membranes derived from both the tonoplast and endoplasmic reticulum were identified within these PSVs. TIP3-GFP-labelled PSVs in the starchy endosperm cells underwent a dramatic reduction in size, so that finally the protein bodies were tightly enclosed. Potential desiccation-related membrane-altering processes that may be causally linked to these dynamic endomembrane events in the barley endosperm are discussed. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Reduced naphthylphthalamic acid binding in the tir3 mutant of Arabidopsis is associated with a reduction in polar auxin transport and diverse morphological defects

NASA Technical Reports Server (NTRS)

Ruegger, M.; Dewey, E.; Hobbie, L.; Brown, D.; Bernasconi, P.; Turner, J.; Muday, G.; Estelle, M.

1997-01-01

Polar auxin transport plays a key role in the regulation of plant growth and development. To identify genes involved in this process, we have developed a genetic procedure to screen for mutants of Arabidopsis that are altered in their response to auxin transport inhibitors. We recovered a total of 16 independent mutants that defined seven genes, called TRANSPORT INHIBITOR RESPONSE (TIR) genes. Recessive mutations in one of these genes, TIR3, result in altered responses to transport inhibitors, a reduction in polar auxin transport, and a variety of morphological defects that can be ascribed to changes in indole-3-acetic acid distribution. Most dramatically, tir3 seedlings are strongly deficient in lateral root production, a process that is known to depend on polar auxin transport from the shoot into the root. In addition, tir3 plants display a reduction in apical dominance as well as decreased elongation of siliques, pedicels, roots, and the inflorescence. Biochemical studies indicate that tir3 plants have a reduced number of N-1-naphthylphthalamic (NPA) binding sites, suggesting that the TIR3 gene is required for expression, localization, or stabilization of the NPA binding protein (NBP). Alternatively, the TIR3 gene may encode the NBP. Because the tir3 mutants have a substantial defect in NPA binding, their phenotype provides genetic evidence for a role for the NBP in plant growth and development.

Stability of an Electrodeposited Nanocrystalline Ni-Based Alloy Coating in Oil and Gas Wells with the Coexistence of H2S and CO2

PubMed Central

Sui, Yiyong; Sun, Chong; Sun, Jianbo; Pu, Baolin; Ren, Wei; Zhao, Weimin

2017-01-01

The stability of an electrodeposited nanocrystalline Ni-based alloy coating in a H2S/CO2 environment was investigated by electrochemical measurements, weight loss method, and surface characterization. The results showed that both the cathodic and anodic processes of the Ni-based alloy coating were simultaneously suppressed, displaying a dramatic decrease of the corrosion current density. The corrosion of the Ni-based alloy coating was controlled by H2S corrosion and showed general corrosion morphology under the test temperatures. The corrosion products, mainly consisting of Ni3S2, NiS, or Ni3S4, had excellent stability in acid solution. The corrosion rate decreased with the rise of temperature, while the adhesive force of the corrosion scale increased. With the rise of temperature, the deposited morphology and composition of corrosion products changed, the NiS content in the corrosion scale increased, and the stability and adhesive strength of the corrosion scale improved. The corrosion scale of the Ni-based alloy coating was stable, compact, had strong adhesion, and caused low weight loss, so the corrosion rates calculated by the weight loss method cannot reveal the actual oxidation rate of the coating. As the corrosion time was prolonged, the Ni-based coating was thinned while the corrosion scale thickened. The corrosion scale was closely combined with the coating, but cannot fully prevent the corrosive reactants from reaching the substrate. PMID:28772995

Negotiating for Change: Modifying Collective Bargaining Agreements for School Turnaround

ERIC Educational Resources Information Center

Weinberg, Rebecca

2011-01-01

Dramatically improving student achievement in a school that has been failing for many years requires dramatically different conditions. Only the most effective teachers and leaders should be in the building, and the leadership must have the flexibility to respond strategically to the needs of the students, with regular input from teachers.…

Dramatic Declines in Higher Education Appropriations: State Conditions for Budget Punctuations

ERIC Educational Resources Information Center

Li, Amy Y.

2017-01-01

Public colleges and universities depend heavily on state appropriations and legislatures must decide how much to fund higher education. This study applies punctuated equilibrium theory to characterize the distribution of annual changes in higher education appropriations and defines the threshold for a dramatic budget cut. Using data for the 50…

Effect of the Cold-Sprayed Aluminum Coating-Substrate Interface Morphology on Bond Strength for Aircraft Repair Application

NASA Astrophysics Data System (ADS)

Blochet, Quentin; Delloro, Francesco; N'Guyen, Franck; Jeulin, Dominique; Borit, François; Jeandin, Michel

2017-04-01

This article is dealing with the effects of surface preparation of the substrate on aluminum cold-sprayed coating bond strength. Different sets of AA2024-T3 specimens have been coated with pure Al 1050 feedstock powder, using a conventional cold spray coating technique. The sets were grit-blasted (GB) before coating. The study focuses on substrate surface topography evolution before coating and coating-substrate interface morphology after coating. To study coating adhesion by LASAT® technique for each set, specimens with and without preceding GB treatment were tested in load-controlled conditions. Then, several techniques were used to evaluate the effects of substrate surface treatment on the final coating mechanical properties. Irregularities induced by the GB treatment modify significantly the interface morphology. Results showed that particle anchoring was improved dramatically by the presence of craters. The substrate surface was characterized by numerous anchors. Numerical simulation results exhibited the increasing deformation of particle onto the grit-blasted surface. In addition, results showed a strong relationship between the coating-substrate bond strength on the deposited material and surface preparation.

Impacts of land use and climate change on carbon dynamics in south-central Senegal

USGS Publications Warehouse

Liu, Shu-Guang; Kaire, M.; Wood, Eric C.; Diallo, O.; Tieszen, Larry L.

2004-01-01

Total carbon stock in vegetation and soils was reduced 37% in south-central Senegal from 1900 to 2000. The decreasing trend will continue during the 21st century unless forest clearing is stopped, selective logging dramatically reduced, and climate change, if any, relatively small. Developing a sustainable fuelwood and charcoal production system could be the most feasible and significant carbon sequestration project in the region. If future climate changes dramatically as some models have predicted, cropland productivity will drop more than 65% around 2100, posing a serious threat to food security and the efficiency of carbon sequestration projects.

Alterations in the Proteome of the Euprymna scolopes Light Organ in Response to Symbiotic Vibrio fischeri

PubMed Central

Doino Lemus, Judith; McFall-Ngai, Margaret J.

2000-01-01

During the onset of the cooperative association between the Hawaiian sepiolid squid Euprymna scolopes and the marine luminous bacterium Vibrio fischeri, the anatomy and morphology of the host's symbiotic organ undergo dramatic changes that require interaction with the bacteria. This morphogenetic process involves an array of tissues, including those in direct contact with, as well as those remote from, the symbiotic bacteria. The bacteria induce the developmental program soon after colonization of the organ, although complete morphogenesis requires 96 h. In this study, to determine critical time points, we examined the biochemistry underlying bacterium-induced host development using two-dimensional polyacrylamide gel electrophoresis. Specifically, V. fischeri-induced changes in the soluble proteome of the symbiotic organ during the first 96 h of symbiosis were identified by comparing the protein profiles of symbiont-colonized and uncolonized organs. Both symbiosis-related changes and age-related changes were analyzed to determine what proportion of the differences in the proteomes was the result of specific responses to interaction with bacteria. Although no differences were detected over the first 24 h, numerous symbiosis-related changes became apparent at 48 and 96 h and were more abundant than age-related changes. In addition, many age-related protein changes occurred 48 h sooner in symbiotic animals, suggesting that the interaction of squid tissue with V. fischeri cells accelerates certain developmental processes of the symbiotic organ. These data suggest that V. fischeri-induced modifications in host tissues that occur in the first 24 h of the symbiosis are independent of marked alterations in the patterns of abundant proteins but that the full 4-day morphogenetic program requires significant alteration of the host soluble proteome. PMID:10966433

Alterations in the proteome of the Euprymna scolopes light organ in response to symbiotic Vibrio fischeri.

PubMed

Doino Lemus, J; McFall-Ngai, M J

2000-09-01

During the onset of the cooperative association between the Hawaiian sepiolid squid Euprymna scolopes and the marine luminous bacterium Vibrio fischeri, the anatomy and morphology of the host's symbiotic organ undergo dramatic changes that require interaction with the bacteria. This morphogenetic process involves an array of tissues, including those in direct contact with, as well as those remote from, the symbiotic bacteria. The bacteria induce the developmental program soon after colonization of the organ, although complete morphogenesis requires 96 h. In this study, to determine critical time points, we examined the biochemistry underlying bacterium-induced host development using two-dimensional polyacrylamide gel electrophoresis. Specifically, V. fischeri-induced changes in the soluble proteome of the symbiotic organ during the first 96 h of symbiosis were identified by comparing the protein profiles of symbiont-colonized and uncolonized organs. Both symbiosis-related changes and age-related changes were analyzed to determine what proportion of the differences in the proteomes was the result of specific responses to interaction with bacteria. Although no differences were detected over the first 24 h, numerous symbiosis-related changes became apparent at 48 and 96 h and were more abundant than age-related changes. In addition, many age-related protein changes occurred 48 h sooner in symbiotic animals, suggesting that the interaction of squid tissue with V. fischeri cells accelerates certain developmental processes of the symbiotic organ. These data suggest that V. fischeri-induced modifications in host tissues that occur in the first 24 h of the symbiosis are independent of marked alterations in the patterns of abundant proteins but that the full 4-day morphogenetic program requires significant alteration of the host soluble proteome.

Microarray analysis identifies keratin loci as sensitive biomarkers for thyroid hormone disruption in the salamander Ambystoma mexicanum.

PubMed

Page, Robert B; Monaghan, James R; Samuels, Amy K; Smith, Jeramiah J; Beachy, Christopher K; Voss, S Randal

2007-02-01

Ambystomatid salamanders offer several advantages for endocrine disruption research, including genomic and bioinformatics resources, an accessible laboratory model (Ambystoma mexicanum), and natural lineages that are broadly distributed among North American habitats. We used microarray analysis to measure the relative abundance of transcripts isolated from A. mexicanum epidermis (skin) after exogenous application of thyroid hormone (TH). Only one gene had a >2-fold change in transcript abundance after 2 days of TH treatment. However, hundreds of genes showed significantly different transcript levels at days 12 and 28 in comparison to day 0. A list of 123 TH-responsive genes was identified using statistical, BLAST, and fold level criteria. Cluster analysis identified two groups of genes with similar transcription patterns: up-regulated versus down-regulated. Most notably, several keratins exhibited dramatic (1000 fold) increases or decreases in transcript abundance. Keratin gene expression changes coincided with morphological remodeling of epithelial tissues. This suggests that keratin loci can be developed as sensitive biomarkers to assay temporal disruptions of larval-to-adult gene expression programs. Our study has identified the first collection of loci that are regulated during TH-induced metamorphosis in a salamander, thus setting the stage for future investigations of TH disruption in the Mexican axolotl and other salamanders of the genus Ambystoma.

In vitro and in vivo evaluation of novel NGR-modified liposomes containing brucine.

PubMed

Li, Shu; Wang, Xi-Peng

2017-01-01

In this study, a novel NGR (Asn-Gly-Arg) peptide-modified liposomal brucine was prepared by using spray-drying method. The surface morphology of the liposomes, encapsulation efficiency and particle size were investigated. The data showed that the addition of NGR did not produce any significant influence on brucine liposomes in terms of particle size or zeta potential. In addition, after 3 months of storage, no dramatic change such as visible aggregation, drug content changes or precipitation in the appearance of NGR-brucine liposomes occurred. The in vitro release results indicated that the release of brucine from NGR liposomes was similar to that of liposomes, demonstrating that the NGR modification did not affect brucine release. The in vitro drug-release kinetic model of NGR-brucine liposomes fitted well with the Weibull's equation. In vivo, NGR-brucine liposomes could significantly extend the bioavailability of brucine; however, there was no significant difference observed in the pharmacokinetic parameters between liposomes and NGR liposomes after intravenous administration. Antitumor activity results showed that NGR-modified liposomes exhibited less toxicity and much higher efficacy in HepG2-bearing mice compared with non-modified liposomes. The enhanced antitumor activity might have occurred because brucine was specifically recognized by NGR receptor on the surface of tumor cells, which enhanced the intracellular uptake of drugs.

Asynchrony in craniomandibular development and growth in Enhydra lutris nereis (Carnivora: Mustelidae): Are southern sea otters born to bite?

USGS Publications Warehouse

Law, Chris J; Baliga, Vikram B.; Tinker, M. Tim; Mehta, Rita S.

2017-01-01

Weaning represents a major ontogenetic dietary shift in southern sea otters (Enhydra lutris nereis), as juveniles must transition from depending on mother’s milk to independently processing hard-shelled invertebrates. When the skulls of juveniles have reached sufficient maturity to transition to a durophagous diet remains to be investigated. Here, we conducted a comprehensive analysis of skull development and growth and sexual dimorphism using geometric morphometric approaches in 204 southern sea otter skulls. We found that southern sea otters of both sexes exhibit dramatic changes in cranial and mandibular shape and size over ontogeny. Although the majority of these changes occur in the pup stage, full development and growth of the skull does not occur until well after weaning. We hypothesize that the slower maturation of the crania of newly weaned juveniles serves as a handicap by constraining jaw adductor muscle size, biting ability and feeding on hard-shelled prey. In our analysis of sexual dimorphism, we found significant sexual shape and size dimorphism in adult craniomandibular morphology that arose through differences in developmental and growth rates and duration. We postulate that males are selected to attain mature crania faster to presumably reach adult biting ability sooner, gaining a competitive advantage in obtaining food and in male–male agonistic interactions.

Calcium oxalate stone formation in the inner ear as a result of an Slc26a4 mutation.

PubMed

Dror, Amiel A; Politi, Yael; Shahin, Hashem; Lenz, Danielle R; Dossena, Silvia; Nofziger, Charity; Fuchs, Helmut; Hrabé de Angelis, Martin; Paulmichl, Markus; Weiner, Steve; Avraham, Karen B

2010-07-09

Calcium oxalate stone formation occurs under pathological conditions and accounts for more than 80% of all types of kidney stones. In the current study, we show for the first time that calcium oxalate stones are formed in the mouse inner ear of a genetic model for hearing loss and vestibular dysfunction in humans. The vestibular system within the inner ear is dependent on extracellular tiny calcium carbonate minerals for proper function. Thousands of these biominerals, known as otoconia, are associated with the utricle and saccule sensory maculae and are vital for mechanical stimulation of the sensory hair cells. We show that a missense mutation within the Slc26a4 gene abolishes the transport activity of its encoded protein, pendrin. As a consequence, dramatic changes in mineral composition, size, and shape occur within the utricle and saccule in a differential manner. Although abnormal giant carbonate minerals reside in the utricle at all ages, in the saccule, a gradual change in mineral composition leads to a formation of calcium oxalate in adult mice. By combining imaging and spectroscopy tools, we determined the profile of mineral composition and morphology at different time points. We propose a novel mechanism for the accumulation and aggregation of oxalate crystals in the inner ear.

Assembly and Function of the Actin Cytoskeleton of Yeast: Relationships between Cables and Patches

PubMed Central

Karpova, Tatiana S.; McNally, James G.; Moltz, Samuel L.; Cooper, John A.

1998-01-01

Actin in eukaryotic cells is found in different pools, with filaments being organized into a variety of supramolecular assemblies. To investigate the assembly and functional relationships between different parts of the actin cytoskeleton in one cell, we studied the morphology and dynamics of cables and patches in yeast. The fine structure of actin cables and the manner in which cables disassemble support a model in which cables are composed of a number of overlapping actin filaments. No evidence for intrinsic polarity of cables was found. To investigate to what extent different parts of the actin cytoskeleton depend on each other, we looked for relationships between cables and patches. Patches and cables were often associated, and their polarized distributions were highly correlated. Therefore, patches and cables do appear to depend on each other for assembly and function. Many cell types show rearrangements of the actin cytoskeleton, which can occur via assembly or movement of actin filaments. In our studies, dramatic changes in actin polarization did not include changes in filamentous actin. In addition, the concentration of actin patches was relatively constant as cells grew. Therefore, cells do not have bursts of activity in which new parts of the actin cytoskeleton are created. PMID:9744880

Recycling of end-of-life reverse osmosis membranes by oxidative treatment: a technical evaluation.

PubMed

Coutinho de Paula, Eduardo; Gomes, Júlia Célia Lima; Amaral, Míriam Cristina Santos

2017-07-01

The adverse impacts caused by the disposal of thousands of tonnes per annum of reverse osmosis (RO) membranes modules have grown dramatically around the world. The objective of this study was to evaluate the technical feasibility of recycling by chemical oxidation of end-of-life RO membranes for applications in other separation processes with specifications less rigorous. The recycling technique consisted in to cause a membrane exposition with oxidant solutions in order to remove its aromatic polyamide layer and subsequent conversion to a porous membrane. The recycling technique was evaluated by water permeability and salt rejection tests before and after the oxidative treatments. Initially, membranes' chemical cleaning and pretreatment procedures were assessed. Among factors evaluated, the oxidizing agent, its concentration and pH, associated with the oxidative treatment time, showed important influence on the oxidation of the membranes. Results showed that sodium hypochlorite and potassium permanganate are efficient agents for the membrane recycling. The great increased permeability and decreased salt rejection indicated changes on membranes' selective properties. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and contact angle characterization techniques revealed marked changes on the main membranes' physical-chemical properties, such as morphology, roughness and hydrophobicity. Reuse of produced effluents and fouling tendency of recycled membranes were also evaluated.

Adsorption of polycyclic aromatic hydrocarbons by graphene and graphene oxide nanosheets.

PubMed

Wang, Jun; Chen, Zaiming; Chen, Baoliang

2014-05-06

The adsorption of naphthalene, phenanthrene, and pyrene onto graphene (GNS) and graphene oxide (GO) nanosheets was investigated to probe the potential adsorptive sites and molecular mechanisms. The microstructure and morphology of GNS and GO were characterized by elemental analysis, XPS, FTIR, Raman, SEM, and TEM. Graphene displayed high affinity to the polycyclic aromatic hydrocarbons (PAHs), whereas GO adsorption was significantly reduced after oxygen-containing groups were attached to GNS surfaces. An unexpected peak was found in the curve of adsorption coefficients (Kd) with the PAH equilibrium concentrations. The hydrophobic properties and molecular sizes of the PAHs affected the adsorption of G and GO. The high affinities of the PAHs to GNS are dominated by π-π interactions to the flat surface and the sieving effect of the powerful groove regions formed by wrinkles on GNS surfaces. In contrast, the adsorptive sites of GO changed to the carboxyl groups attaching to the edges of GO because the groove regions disappeared and the polar nanosheet surfaces limited the π-π interactions. The TEM and SEM images initially revealed that after loading with PAH, the conformation and aggregation of GNS and GO nanosheets dramatically changed, which explained the observations that the potential adsorption sites of GNS and GO were unusually altered during the adsorption process.

Finding sacral: Developmental evolution of the axial skeleton of odontocetes (Cetacea).

PubMed

Buchholtz, Emily A; Gee, Jessica K

2017-07-01

Axial morphology was dramatically transformed during the transition from terrestrial to aquatic environments by archaeocete cetaceans, and again during the subsequent odontocete radiation. Here, we reconstruct the sequence of developmental events that underlie these phenotypic transitions. Archaeocete innovations include the loss of primaxial/abaxial interaction at the sacral/pelvic articulation and the modular dissociation of the fluke from the remainder of the tail. Odontocetes subsequently integrated lumbar, sacral, and anterior caudal vertebrae into a single torso module, and underwent multiple series-specific changes in vertebral count. The conservation of regional proportions despite regional fluctuations in count strongly argues that rates of somitogenesis can vary along the column and that segmentation was dissociated from regionalization during odontocete evolution. Conserved regional proportions also allow the prediction of the location and count of sacral homologs within the torso module. These predictions are tested with the analysis of comparative pudendal nerve root location and geometric morphometrics. We conclude that the proportion of the column represented by the sacral series has been conserved, and that its vertebrae have changed in count and relative centrum length in parallel with other torso vertebrae. Although the sacral series of odontocetes is de-differentiated, it is not de-regionalized. © 2017 Wiley Periodicals, Inc.

Probability and surprisal in auditory comprehension of morphologically complex words.

PubMed

Balling, Laura Winther; Baayen, R Harald

2012-10-01

Two auditory lexical decision experiments document for morphologically complex words two points at which the probability of a target word given the evidence shifts dramatically. The first point is reached when morphologically unrelated competitors are no longer compatible with the evidence. Adapting terminology from Marslen-Wilson (1984), we refer to this as the word's initial uniqueness point (UP1). The second point is the complex uniqueness point (CUP) introduced by Balling and Baayen (2008), at which morphologically related competitors become incompatible with the input. Later initial as well as complex uniqueness points predict longer response latencies. We argue that the effects of these uniqueness points arise due to the large surprisal (Levy, 2008) carried by the phonemes at these uniqueness points, and provide independent evidence that how cumulative surprisal builds up in the course of the word co-determines response latencies. The presence of effects of surprisal, both at the initial uniqueness point of complex words, and cumulatively throughout the word, challenges the Shortlist B model of Norris and McQueen (2008), and suggests that a Bayesian approach to auditory comprehension requires complementation from information theory in order to do justice to the cognitive cost of updating probability distributions over lexical candidates. Copyright © 2012 Elsevier B.V. All rights reserved.

The effects of some polyamine biosynthetic inhibitors on growth and morphology of phytopathogenic fungi

NASA Technical Reports Server (NTRS)

Rajam, M. V.; Galston, A. W.

1985-01-01

We have studied the effects of two polyamine biosynthetic inhibitors, alpha-difluoromethylornithine (DFMO) and alpha-difluoromethylarginine (DFMA), and of polyamines (PAs), alone and in combination, on mycelial growth and morphology of four phytopathogenic fungi: Botrytis sp, B. cinerea, Rhizoctonia solani and Monilinia fructicola. The inhibitors were added to a Czapek agar medium to get final concentrations of 0.1, 0.5 and 1.0 mM. DFMO and DFMA, suicide inhibitors of ornithine decarboxylase (ODC) and arginine decarboxylase (ADC) respectively, inhibited mycelial growth strongly; the effect was generally more pronounced with DFMA than with DFMO, but each fungus had its own response pattern. The addition of the PAs putrescine (Put) and spermidine (Spd) to the culture medium resulted in a promotion of growth. In Botrytis sp and Monilinia fructicola exposed to inhibitors plus PAs, mycelial growth was actually increased above control values. Mycelial morphology was altered and cell size dramatically reduced in plates containing inhibitors alone, whereas with PAs alone, or in combination with inhibitors, morphology was normal, but cell length and diameters increased considerably. These results suggest that PAs are essential for growth in fungal mycelia. The inhibition caused by DFMA may be due to its arginase-mediated conversion to DFMO.

An investigation of the degradation of Fluorinated Ethylene Propylene (FEP) copolymer thermal blanketing materials aboard LDEF in the laboratory

NASA Technical Reports Server (NTRS)

Stiegman, A. E.; Brinza, David E.; Anderson, Mark S.; Minton, Timothy K.; Laue, Eric G.; Liang, Ranty H.

1991-01-01

Samples of fluorinated ethylene propylene copolymer thermal blanketing material, recovered from the Long Duration Exposure Facility (LDEF), were investigated to determine the nature and the extent of degradation due to exposure to the low-Earth-orbit environment. Samples recovered from the ram-facing direction of LDEF, which received vacuum-ultraviolet (VUV) radiation and atomic-oxygen impingement, and samples from the trailing edge, which received almost exclusively VUV exposure, were investigated by scanning electron microscopy and atomic force microscopy. The most significant result of this investigation was found on samples that received only VUV exposure. These samples possessed a hard, embrittled surface layer that was absent from the atomic-oxygen exposed sample and from unexposed control samples. This surface layer is believed to be responsible for the 'synergistic' effect between VUV and atomic oxygen. Overall, the investigation revealed dramatically different morphologies for the two samples. The sample receiving both atomic-oxygen and VUV exposure was deeply eroded and had a characteristic 'rolling' surface morphology, while the sample that received only VUV exposure showed mild erosion and a surface morphology characterized by sharp high-frequency peaks. The morphologies observed in the LDEF samples, including the embrittled surface layer, were successfully duplicated in the laboratory.

Investigation of Techniques for Inventorying Forested Regions. Volume 1: Reflectance Modeling and Empirical Multispectral Analysis of Forest Canopy Components

NASA Technical Reports Server (NTRS)

Nalepka, R. F. (Principal Investigator); Sadowski, F. G.; Malila, W. A.

1977-01-01

The author has identified the following significant results. Effects of vegetation density on overall canopy reflectance differed dramatically, depending on spectral band, base material, and vegetation type. For example, reflectance changes caused by variations in vegetation density were hardly apparant for a simulated burned surface in LANDSAT band 5, while large changes occurred in band 7. When increasing densities of tree overstory were placed over understories, intermediate to dense overstories effectively masked the understories and dominated the spectral signatures. Dramatic changes in reflectance occurred for canopies placed on a number of varying topographic positions. Such changes were seen to result in the spectral overlap of some nonforested with densely forested situations.

Burning Fossil Fuels: Impact of Climate Change on Health.

PubMed

Sommer, Alfred

2016-01-01

A recent, sophisticated granular analysis of climate change in the United States related to burning fossil fuels indicates a high likelihood of dramatic increases in temperature, wet-bulb temperature, and precipitation, which will dramatically impact the health and well-being of many Americans, particularly the young, the elderly, and the poor and marginalized. Other areas of the world, where they lack the resources to remediate these weather impacts, will be even more greatly affected. Too little attention is being paid to the impending health impact of accumulating greenhouse gases. © The Author(s) 2015.

Effects of temperature and cellular interactions on the mechanics and morphology of human cancer cells investigated by atomic force microscopy.

PubMed

Li, Mi; Liu, LianQing; Xi, Ning; Wang, YueChao; Xiao, XiuBin; Zhang, WeiJing

2015-09-01

Cell mechanics plays an important role in cellular physiological activities. Recent studies have shown that cellular mechanical properties are novel biomarkers for indicating the cell states. In this article, temperature-controllable atomic force microscopy (AFM) was applied to quantitatively investigate the effects of temperature and cellular interactions on the mechanics and morphology of human cancer cells. First, AFM indenting experiments were performed on six types of human cells to investigate the changes of cellular Young's modulus at different temperatures and the results showed that the mechanical responses to the changes of temperature were variable for different types of cancer cells. Second, AFM imaging experiments were performed to observe the morphological changes in living cells at different temperatures and the results showed the significant changes of cell morphology caused by the alterations of temperature. Finally, by co-culturing human cancer cells with human immune cells, the mechanical and morphological changes in cancer cells were investigated. The results showed that the co-culture of cancer cells and immune cells could cause the distinct mechanical changes in cancer cells, but no significant morphological differences were observed. The experimental results improved our understanding of the effects of temperature and cellular interactions on the mechanics and morphology of cancer cells.

How to Know when Dramatic Change Is on Track: Leading Indicators of School Turnarounds

ERIC Educational Resources Information Center

Kowal, Julie; Ableidinger, Joe

2011-01-01

In recent years, national policymakers have placed new emphasis on "school turnarounds" as a strategy for rapid, dramatic improvement in chronically failing schools, calling on education leaders to turn around performance in the 5,000 lowest-achieving schools nationwide. This goal may seem daunting, given the dismal success rates of…

Accurate Detection of Dysmorphic Nuclei Using Dynamic Programming and Supervised Classification.

PubMed

Verschuuren, Marlies; De Vylder, Jonas; Catrysse, Hannes; Robijns, Joke; Philips, Wilfried; De Vos, Winnok H

2017-01-01

A vast array of pathologies is typified by the presence of nuclei with an abnormal morphology. Dysmorphic nuclear phenotypes feature dramatic size changes or foldings, but also entail much subtler deviations such as nuclear protrusions called blebs. Due to their unpredictable size, shape and intensity, dysmorphic nuclei are often not accurately detected in standard image analysis routines. To enable accurate detection of dysmorphic nuclei in confocal and widefield fluorescence microscopy images, we have developed an automated segmentation algorithm, called Blebbed Nuclei Detector (BleND), which relies on two-pass thresholding for initial nuclear contour detection, and an optimal path finding algorithm, based on dynamic programming, for refining these contours. Using a robust error metric, we show that our method matches manual segmentation in terms of precision and outperforms state-of-the-art nuclear segmentation methods. Its high performance allowed for building and integrating a robust classifier that recognizes dysmorphic nuclei with an accuracy above 95%. The combined segmentation-classification routine is bound to facilitate nucleus-based diagnostics and enable real-time recognition of dysmorphic nuclei in intelligent microscopy workflows.

Accurate Detection of Dysmorphic Nuclei Using Dynamic Programming and Supervised Classification

PubMed Central

Verschuuren, Marlies; De Vylder, Jonas; Catrysse, Hannes; Robijns, Joke; Philips, Wilfried

2017-01-01

A vast array of pathologies is typified by the presence of nuclei with an abnormal morphology. Dysmorphic nuclear phenotypes feature dramatic size changes or foldings, but also entail much subtler deviations such as nuclear protrusions called blebs. Due to their unpredictable size, shape and intensity, dysmorphic nuclei are often not accurately detected in standard image analysis routines. To enable accurate detection of dysmorphic nuclei in confocal and widefield fluorescence microscopy images, we have developed an automated segmentation algorithm, called Blebbed Nuclei Detector (BleND), which relies on two-pass thresholding for initial nuclear contour detection, and an optimal path finding algorithm, based on dynamic programming, for refining these contours. Using a robust error metric, we show that our method matches manual segmentation in terms of precision and outperforms state-of-the-art nuclear segmentation methods. Its high performance allowed for building and integrating a robust classifier that recognizes dysmorphic nuclei with an accuracy above 95%. The combined segmentation-classification routine is bound to facilitate nucleus-based diagnostics and enable real-time recognition of dysmorphic nuclei in intelligent microscopy workflows. PMID:28125723

Ion-Implanted Diamond Films and Their Tribological Properties

NASA Technical Reports Server (NTRS)

Wu, Richard L. C.; Miyoshi, Kazuhisa; Korenyi-Both, Andras L.; Garscadden, Alan; Barnes, Paul N.

1993-01-01

This paper reports the physical characterization and tribological evaluation of ion-implanted diamond films. Diamond films were produced by microwave plasma, chemical vapor deposition technique. Diamond films with various grain sizes (0.3 and 3 microns) and roughness (9.1 and 92.1 nm r.m.s. respectively) were implanted with C(+) (m/e = 12) at an ion energy of 160 eV and a fluence of 6.72 x 10(exp 17) ions/sq cm. Unidirectional sliding friction experiments were conducted in ultrahigh vacuum (6.6 x 10(exp -7)Pa), dry nitrogen and humid air (40% RH) environments. The effects of C(+) ion bombardment on fine and coarse-grained diamond films are as follows: the surface morphology of the diamond films did not change; the surface roughness increased (16.3 and 135.3 nm r.m.s.); the diamond structures were damaged and formed a thin layer of amorphous non-diamond carbon; the friction coefficients dramatically decreased in the ultrahigh vacuum (0.1 and 0.4); the friction coefficients decreased slightly in the dry nitrogen and humid air environments.

Specificity Bio-identification of CNT-Based Transistor

NASA Astrophysics Data System (ADS)

Wang, Sheng-Yu; Wu, Hue-Min

2017-12-01

In this research, we report a simple and general approach to π-π stacking functionalization of the sidewalls of CNTs by 1-pyrenebutanoic acid, succinimidyl ester (PSE), and subsequent immobilization of insulin-like growth factor 1 receptor (IGF1R) onto SWNTs with a high degree of control and specificity. The selection of PSE provides visualization and characterization of individual CNTs based on its strong luminescence. In addition, we designed a simple and efficient electrode with a staggered pattern to increase the effect of electrophoresis by using electric field for the macroscopic alignment of CNTs to complete a field-effect device for CNT-based biosensors. Scanning Electron Microscopy (SEM) was used to investigate the morphology of the biosensors. The results of four-point probe method demonstrated high selectivity and sensitivity of detection. The functionalization of SWNTs was investigated by Fourier transform infrared spectroscopy (FTIR). Experimental results imply that specific binding between IGF1R and its specific mAb results in a dramatic change in electrical current of CNT-based devices, and suggest that the devices are very promising biosensor candidates to detect circulating cancer cells.

Loss of MyoD and Myf5 in Skeletal Muscle Stem Cells Results in Altered Myogenic Programming and Failed Regeneration.

PubMed

Yamamoto, Masakazu; Legendre, Nicholas P; Biswas, Arpita A; Lawton, Alexander; Yamamoto, Shoko; Tajbakhsh, Shahragim; Kardon, Gabrielle; Goldhamer, David J

2018-03-13

MyoD and Myf5 are fundamental regulators of skeletal muscle lineage determination in the embryo, and their expression is induced in satellite cells following muscle injury. MyoD and Myf5 are also expressed by satellite cell precursors developmentally, although the relative contribution of historical and injury-induced expression to satellite cell function is unknown. We show that satellite cells lacking both MyoD and Myf5 (double knockout [dKO]) are maintained with aging in uninjured muscle. However, injured muscle fails to regenerate and dKO satellite cell progeny accumulate in damaged muscle but do not undergo muscle differentiation. dKO satellite cell progeny continue to express markers of myoblast identity, although their myogenic programming is labile, as demonstrated by dramatic morphological changes and increased propensity for non-myogenic differentiation. These data demonstrate an absolute requirement for either MyoD or Myf5 in muscle regeneration and indicate that their expression after injury stabilizes myogenic identity and confers the capacity for muscle differentiation. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Role of Epithelial Mesenchymal Transition in Prostate Tumorigenesis

PubMed Central

Khan, Mohammad Imran; Hamid, Abid; Adhami, Vaqar Mustafa; Lall, Rahul K; Mukhtar, Hasan

2015-01-01

Globally, the cancer associated deaths are generally attributed to the spread of cancerous cells or their features to the nearby or distant secondary organs by a process known as metastasis. Among other factors, the metastatic dissemination of cancer cells is attributed to the reactivation of an evolutionary conserved developmental program known as epithelial to mesenchymal transition (EMT). During EMT, fully differentiated epithelial cells undergo a series of dramatic changes in their morphology, along with loss of cell to cell contact and matrix remodeling into less differentiated and invasive mesenchymal cells. Many studies provide evidence for the existence of EMT like states in prostate cancer (PCa) and suggest its possible involvement in PCa progression and metastasis. At the same time, the lack of conclusive evidence regarding the presence of full EMT in human PCa samples has somewhat dampened the interest in the field. However, ongoing EMT research provides new perspectives and unveils the enormous potential of this field in tailoring new therapeutic regimens for PCa management. This review summarizes the role of many transcription factors and other molecules that drive EMT during prostate tumorigenesis. PMID:25506896

Current tecniques and new perpectives research of magnetic resonance enterography in pediatric Crohn’s disease

PubMed Central

Masselli, Gabriele; Mastroiacovo, Ilaria; De Marco, Emidio; Francione, Giulia; Casciani, Emanuele; Polettini, Elisabetta; Gualdi, Gianfranco

2016-01-01

Crohn’s disease affects more than 500000 individuals in the United States, and about 25% of cases are diagnosed during the pediatric period. Imaging of the bowel has undergone dramatic changes in the past two decades. The endoscopy with biopsy is generally considered the diagnostic reference standard, this combination can evaluates only the mucosa, not inflammation or fibrosis in the mucosa. Actually, the only modalities that can visualize submucosal tissues throughout the small bowel are the computed tomography (CT) enterography (CTE) with the magnetic resonance enterography (MRE). CT generally is highly utilized, but there is growing concern over ionizing radiation and cancer risk; it is a very important aspect to keep in consideration in pediatric patients. In contrast to CTE, MRE does not subject patients to ionizing radiation and can be used to detect detailed morphologic information and functional data of bowel disease, to monitor the effects of medical therapy more accurately, to detect residual active disease even in patients showing apparent clinical resolution and to guide treatment more accurately. PMID:27551337

Incorporating 2D Materials with Micro-electromechanical Systems to Explore Strain Physics and Devices

NASA Astrophysics Data System (ADS)

Christopher, Jason; Vutukuru, Mounika; Kohler, Travis; Bishop, David; Swan, Anna; Goldberg, Bennett

2D materials can withstand an order of magnitude more strain than their bulk counterparts which can be used to dramatically change electrical, thermal and optical properties or even cause unconventional behavior such as generating pseudo-magnetic fields. Here we present micro-electromechanical systems (MEMS) as a platform for straining 2D materials to make such novel phenomena accessible. Unlike other strain techniques, MEMS are capable of precisely controlling the magnitude and orientation of the strain field and are readily integrated with current technology facilitating a path from lab bench to application. In this study, we use graphene as our prototypical 2D material, and determine strain via micro-Raman spectroscopy making extensive use of graphene's well-characterized phonon strain response. We report on the strength of various techniques for affixing graphene to MEMS, and investigate the role of surface morphology and chemistry in creating a high friction interface capable of inducing large strain. This work is supported by NSF DMR Grant 1411008, and author J. Christopher thanks the NDSEG program for its support.

Plasmonic resonances in hybrid systems of aluminum nanostructured arrays and few layer graphene within the UV-IR spectral range

NASA Astrophysics Data System (ADS)

González-Campuzano, R.; Saniger, J. M.; Mendoza, D.

2017-11-01

The size-controllable and ordered Al nanocavities and nanodomes arrays were synthesized by electrochemical anodization of aluminum using phosphoric acid, citric acid and mixture both acids. Few layer graphene (FLG) was transferred directly on top of Al nanostructures and their morphology were evaluated by scanning electron microscopy. The interaction between FLG and the plasmonic properties of Al nanostructures arrays were investigated based on specular reflectivity in the ultraviolet-visible-infrared range and Raman spectroscopy. We found that their optical reflectivity was dramatically reduced as compared with unstructured Al. At the same time pronounced reflectivity dips were detectable in the 200-896 nm wavelength range, which were ascribed to plasmonic resonances. The plasmonic properties of these nanostructures do not exhibit evident changes by the presence of FLG in the UV-vis range of the electromagnetic spectrum. By contrast, the surface-enhanced Raman spectroscopy of FLG was observed in nanocavities and nanodomes structures that result in an intensity increase of the characteristic G and 2D bands of FLG induced by the plasmonic properties of Al nanostructures.

Development of a high-content screening assay panel to accelerate mechanism of action studies for oncology research.

PubMed

Towne, Danli L; Nicholl, Emily E; Comess, Kenneth M; Galasinski, Scott C; Hajduk, Philip J; Abraham, Vivek C

2012-09-01

Efficient elucidation of the biological mechanism of action of novel compounds remains a major bottleneck in the drug discovery process. To address this need in the area of oncology, we report the development of a multiparametric high-content screening assay panel at the level of single cells to dramatically accelerate understanding the mechanism of action of cell growth-inhibiting compounds on a large scale. Our approach is based on measuring 10 established end points associated with mitochondrial apoptosis, cell cycle disruption, DNA damage, and cellular morphological changes in the same experiment, across three multiparametric assays. The data from all of the measurements taken together are expected to help increase our current understanding of target protein functions, constrain the list of possible targets for compounds identified using phenotypic screens, and identify off-target effects. We have also developed novel data visualization and phenotypic classification approaches for detailed interpretation of individual compound effects and navigation of large collections of multiparametric cellular responses. We expect this general approach to be valuable for drug discovery across multiple therapeutic areas.

Measuring Apoptosis by Microscopy and Flow Cytometry.

PubMed

Hollville, Emilie; Martin, Seamus J

2016-02-02

Apoptosis is a mode of programmed cell death that plays an important role during development and in the maintenance of tissue homeostasis. Numerous physiological as well as pathological stimuli trigger apoptosis such as engagement of Fas, TRAIL, or TNF receptors, growth factor deprivation, hypoxia, or exposure to cytotoxic drugs. Apoptosis is coordinated from within by members of the caspase family of cysteine proteases that, upon activation, trigger a series of morphological changes including cell shrinkage, extensive plasma membrane blebbing, chromatin condensation, DNA hydrolysis, and nuclear fragmentation. These dramatic structural and biochemical alterations result not only in the controlled dismantling of the cell, but also in the efficient recognition and removal of apoptotic cells by phagocytes. Necrosis, which is typically nonprogrammed or imposed upon the cell by overwhelming membrane or organelle damage, is characterized by rapid plasma membrane rupture followed by organelle and cell swelling. Necrosis is often provoked by infectious agents or a severe departure from physiological conditions. This unit describes protocols for the measurement of apoptosis and for distinguishing apoptosis from necrosis. Copyright © 2016 John Wiley & Sons, Inc.

Interfacial preparation and optical transmission surface plasmon resonance of Janus metamaterials membrane

NASA Astrophysics Data System (ADS)

Du, Yixuan; Zhang, Xiaowei; Li, Yunbo

2018-01-01

Janus metamaterials membrane had been fabricated using self-assembly strategy at the oil/water interface with thiol-terminated polymers. Janus metamaterials membrane exhibits a characteristic surface plasmon absorption band, in which the peak position is sensitive to the addition of polymer. The optical transmission surface plasmon resonance (T-SPR) peak has a blue shift at the visible region with addition of thiol-terminated polystyrene (PS-SH). With thiol-terminated poly (ethylene glycol) (PEG-SH) attachment onto the surface side of gold nanoparticles (AuNPs), the T-SPR band has a successive blue shift. One surprising thing is that it has a flat terrace on T-SPR band from 580 to 740 nm. In addition, The T-SPR of Janus metamaterials membrane dramatically changed with the addition PS-SH when the PEG-SH was capped on the opposite side. The morphologies of AuNPs membrane and Janus metamaterials membrane support the above mentioned result of SPR. In virtue of tunable SPR band, the Janus metamaterials membrane has great potential application in science-based design of optical sensing sensors and surface-enhanced optic sensitive detection.

Antimicrobial effect and membrane-active mechanism of tea polyphenols against Serratia marcescens.

PubMed

Yi, Shumin; Wang, Wei; Bai, Fengling; Zhu, Junli; Li, Jianrong; Li, Xuepeng; Xu, Yongxia; Sun, Tong; He, Yutang

2014-02-01

In this study, we investigated the antimicrobial effect of tea polyphenols (TP) against Serratia marcescens and examined the related mechanism. Morphology changes of S. marcescens were first observed by transmission electron microscopy after treatment with TP, which indicated that the primary inhibition action of TP was to damage the bacterial cell membranes. The permeability of the outer and inner membrane of S. marcescens dramatically increased after TP treatment, which caused severe disruption of cell membrane, followed by the release of small cellular molecules. Furthermore, a proteomics approach based on two-dimensional gel electrophoresis and MALDI-TOF/TOF MS analysis was used to study the difference of membrane protein expression in the control and TP treatment S. marcescens. The results showed that the expression of some metabolism enzymes and chaperones in TP-treated S. marcescens significantly increased compared to the untreated group, which might result in the metabolic disorder of this bacteria. Taken together, our results first demonstrated that TP had a significant growth inhibition effect on S. marcescens through cell membrane damage.

Processing of carbamazepine-PEG 4000 solid dispersions with supercritical carbon dioxide: preparation, characterisation, and in vitro dissolution.

PubMed

Moneghini, M; Kikic, I; Voinovich, D; Perissutti, B; Filipović-Grcić, J

2001-07-03

The purpose of this study was to apply the attractive technique of the supercritical fluid to the preparation of solvent-free solid dispersions. In particular, the gas antisolvent crystallisation technique (GAS), using supercritical carbon dioxide as processing medium, has been considered to prepare an enhanced release dosage form for of the poorly soluble carbamazepine, employing PEG 4000 as a hydrophilic carrier. The physical characterisation of the systems using laser granulometer, powder X-ray diffraction, thermal analyses, and scanning electron microscopy was carried out in order to understand the influence of this technological process on the physical status of the drug. The results of the physical characterisation attested a substantial correspondence of the solid state of the drug before and after treatment with GAS technique, whereas a pronounced change in size and morphology of the drug crystals was noticed. The dramatic reduction of the dimensions and the better crystal shape, together with the presence of the hydrophilic polymer determined a remarkable enhancement of the in vitro drug dissolution rate.

The antagonistic modulation of Arp2/3 activity by N-WASP, WAVE2 and PICK1 defines dynamic changes in astrocyte morphology.

PubMed

Murk, Kai; Blanco Suarez, Elena M; Cockbill, Louisa M R; Banks, Paul; Hanley, Jonathan G

2013-09-01

Astrocytes exhibit a complex, branched morphology, allowing them to functionally interact with numerous blood vessels, neighboring glial processes and neuronal elements, including synapses. They also respond to central nervous system (CNS) injury by a process known as astrogliosis, which involves morphological changes, including cell body hypertrophy and thickening of major processes. Following severe injury, astrocytes exhibit drastically reduced morphological complexity and collectively form a glial scar. The mechanistic details behind these morphological changes are unknown. Here, we investigate the regulation of the actin-nucleating Arp2/3 complex in controlling dynamic changes in astrocyte morphology. In contrast to other cell types, Arp2/3 inhibition drives the rapid expansion of astrocyte cell bodies and major processes. This intervention results in a reduced morphological complexity of astrocytes in both dissociated culture and in brain slices. We show that this expansion requires functional myosin II downstream of ROCK and RhoA. Knockdown of the Arp2/3 subunit Arp3 or the Arp2/3 activator N-WASP by siRNA also results in cell body expansion and reduced morphological complexity, whereas depleting WAVE2 specifically reduces the branching complexity of astrocyte processes. By contrast, knockdown of the Arp2/3 inhibitor PICK1 increases astrocyte branching complexity. Furthermore, astrocyte expansion induced by ischemic conditions is delayed by PICK1 knockdown or N-WASP overexpression. Our findings identify a new morphological outcome for Arp2/3 activation in restricting rather than promoting outwards movement of the plasma membrane in astrocytes. The Arp2/3 regulators PICK1, and N-WASP and WAVE2 function antagonistically to control the complexity of astrocyte branched morphology, and this mechanism underlies the morphological changes seen in astrocytes during their response to pathological insult.

Cretaceous flowers of Nymphaeaceae and implications for complex insect entrapment pollination mechanisms in early angiosperms.

PubMed

Gandolfo, M A; Nixon, K C; Crepet, W L

2004-05-25

Based on recent molecular systematics studies, the water lily lineage (Nymphaeales) provides an important key to understanding ancestral angiosperm morphology and is of considerable interest in the context of angiosperm origins. Therefore, the fossil record of Nymphaeales potentially provides evidence on both the timing and nature of diversification of one of the earliest clades of flowering plants. Recent fossil evidence of Turonian age (approximately 90 million years B.P.) includes fossil flowers with characters that, upon rigorous analysis, firmly place them within Nymphaeaceae. Unequivocally the oldest floral record of the Nymphaeales, these fossils are closely related to the modern Nymphaealean genera Victoria (the giant Amazon water lily) and Euryale. Although the fossils are much smaller than their modern relatives, the precise and dramatic correspondence between the fossil floral morphology and that of modern Victoria flowers suggests that beetle entrapment pollination was present in the earliest part of the Late Cretaceous.

Effects of inherent/enhanced solid acidity and morphology of diatomite templates on the synthesis and porosity of hierarchically porous carbon.

PubMed

Liu, Dong; Yuan, Peng; Tan, Daoyong; Liu, Hongmei; Fan, Mingde; Yuan, Aihua; Zhu, Jianxi; He, Hongping

2010-12-21

The inherent or enhanced solid acidity of raw or activated diatomite is found to have significant effects on the synthesis of hierarchically porous diatomite-templated carbon with high surface area and special porous structure. The solid acidity makes raw/activated diatomite a catalyst for the generation of porous carbon, and the porous parameters of the carbon products are strongly dependent on the solid acidity of diatomite templates. The morphology of diatomite also dramatically affects the textural structure of porous carbon. Two types of macroporous structures in the carbon product, the partially solid pillars and the ordered hollow tubes, derive from the replication of the central and the edge pores of diatom shell, respectively. The hierarchically porous carbon shows good capability for the adsorption of solvent naphtha and H(2), enabling potential applications in adsorption and gas storage.

Polycrystalline BiFeO{sub 3} thin film synthesized via sol-gel assisted spin coating technique for photosensitive application

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

Bogle, K. A., E-mail: kashinath.bogle@gmail.com; Narwade, R. D.; Mahabole, M. P.

2016-05-06

We are reporting photosensitivity property of BiFeO{sub 3} thin film under optical illumination. The thin film used for photosensitivity work was fabricated via sol-gel assisted spin coating technique. I-V measurements on the Cu/BiFeO{sub 3}/Al structure under dark condition show a good rectifying property and show dramatic blue shit in threshold voltage under optical illumination. The microstructure, morphology and elemental analysis of the films were characterized by using XRD, UV-Vis, FTIR, SEM and EDS.

Enhancement of the inverted polymer solar cells via ZnO doped with CTAB

NASA Astrophysics Data System (ADS)

Sivashnamugan, Kundan; Guo, Tzung-Fang; Hsu, Yao-Jane; Wen, Ten-Chin

2018-02-01

A facile approach enhancing electron extraction in zinc oxide (ZnO) electron transfer interlayer and improving performance of bulk-heterojunction (BHJ) polymer solar cells (PSCs) by adding cetyltrimethylammonium bromide (CTAB) into sol-gel ZnO precursor solution was demonstrated in this work. The power conversion efficiency (PCE) has a 24.1% increment after modification. Our results show that CTAB can dramatically influence optical, electrical and morphological properties of ZnO electron transfer layer, and work as effective additive to enhance the performance of bulk- heterojunction polymer solar cells.

Land-cover change detection

USGS Publications Warehouse

Chen, Xuexia; Giri, Chandra; Vogelmann, James

2012-01-01

Land cover is the biophysical material on the surface of the earth. Land-cover types include grass, shrubs, trees, barren, water, and man-made features. Land cover changes continuously.  The rate of change can be either dramatic and abrupt, such as the changes caused by logging, hurricanes and fire, or subtle and gradual, such as regeneration of forests and damage caused by insects (Verbesselt et al., 2001).  Previous studies have shown that land cover has changed dramatically during the past sevearal centuries and that these changes have severely affected our ecosystems (Foody, 2010; Lambin et al., 2001). Lambin and Strahlers (1994b) summarized five types of cause for land-cover changes: (1) long-term natural changes in climate conditions, (2) geomorphological and ecological processes, (3) human-induced alterations of vegetation cover and landscapes, (4) interannual climate variability, and (5) human-induced greenhouse effect.  Tools and techniques are needed to detect, describe, and predict these changes to facilitate sustainable management of natural resources.

Dynamics of clade diversification on the morphological hypercube

PubMed Central

Gavrilets, S.

1999-01-01

Understanding the relationship between taxonomic and morphological changes is important in identifying the reasons for accelerated morphological diversification early in the history of animal phyla. Here, a simple general model describing the joint dynamics of taxonomic diversity and morphological disparity is presented and applied to the data on the diversification of blastozoans. I show that the observed patterns of deceleration in clade diversification can be explicable in terms of the geometric structure of the morphospace and the effects of extinction and speciation on morphological disparity without invoking major declines in the size of morphological transitions or taxonomic turnover rates. The model allows testing of hypotheses about patterns of diversification and estimation of rates of morphological evolution. In the case of blastozoans, I find no evidence that major changes in evolutionary rates and mechanisms are responsible for the deceleration of morphological diversification seen during the period of this clade's expansion. At the same time, there is evidence for a moderate decline in overall rates of morphological diversification concordant with a major change (from positive to negative values) in the clade's growth rate.

Melanoma or Pseudo melanoma Change in a pigmented lesion after application of topical 5-Fluorouracil

DTIC Science & Technology

2017-10-26

morphologic change in a pigmented lesion following topical field therapy with 5-FU for actinic damage on the trunk. After four weeks of twice daily...morphologic change in a pigmented lesion following topical field therapy with 5-FU for actinic damage on the trunk. After four weeks of twice daily...After four weeks of twice daily application, a previously benign appearing pigmented lesion displayed a change in clinical morphology that

Conserving biodiversity on Mongolian Rangelands: Implications for protected area development and pastoral uses

Treesearch

Richard P. Reading; Donald J. Bedunah; Sukhiin Amgalanbaatar

2006-01-01

Mongolia is a sparsely populated country with over 80 percent of its land used by pastoralists for extensive livestock grazing. Mongolia’s wildlife and pastoralists have faced dramatic challenges with the recent rapid socioeconomic changes. Livestock numbers increased dramatically in the 1990s following the transition from communism to democracy and capitalism. Yet,...

Public health and clinical importance of amoebiasis in Malaysia: a review.

PubMed

Tengku, S A; Norhayati, M

2011-08-01

Entamoeba histolytica, the causative agent of human amoebiasis remains a significant cause of morbidity and mortality in developing countries and is responsible for up to 100,000 deaths worldwide each year. Entamoeba dispar, morphologically indistinguishable from E. histolytica is more common in humans in many parts of the world. Similarly Entamoeba moshkovskii, which was long considered to be a free-living amoeba is also morphologically identical to E. histolytica and E. dispar, and is highly prevalent in some E. histolytica endemic countries. Humans are the host of infection and there would not appear to be other meaningful animal reservoirs of E. histolytica. Entamoeba. histolytica can be present in sewage and contaminated water. The infection is mainly transmitted via ingestion of water or food contaminated by faeces containing E. histolytica cysts. Clinical features of amoebiasis range from asymptomatic colonization to amoebic dysentery and invasive extraintestinal amoebiasis, which is manifested most commonly in the form of abscesses in liver and lungs. The epidemiology of amoebiasis has dramatically changed since the separation of E. histolytica and E. dispar species and the worldwide prevalence of these species has not been estimated until recently. Morever, E. moshkovskii, another morphologically indistinguishable human parasitic Entamoeba was not mentioned or considered as a contributor to the prevalence figures in endemic areas. Amoebiasis is still a major health problem especially in aboriginal settlements and amongst people living in remote area in Malaysia. However, until now there is only one data currently available to indicate the true prevalence and incidence of E. histolytica and E. dispar. Further studies are needed to determine the burden of E. histolytica, E. dispar and E. moshkovskii infections in Malaysia. In the present review, we briefly summarize all methods use in diagnosing Entamoeba species, ranging from microscopic identification to molecular detection such as culture and isoenzyme analysis, antibody detection tests, antigen detection tests, immunochromatographic assays, conventional PCR, real-time PCR and loop-mediated isothermal amplification (LAMP).

Selective alterations of the host cell architecture upon infection with parvovirus minute virus of mice

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

Nueesch, Juerg P.F.; Lachmann, Sylvie; Rommelaere, Jean

During a productive infection, the prototype strain of parvovirus minute virus of mice (MVMp) induces dramatic morphological alterations to the fibroblast host cell A9, resulting in cell lysis and progeny virus release. In order to understand the mechanisms underlying these changes, we characterized the fate of various cytoskeletal filaments and investigated the nuclear/cytoplasmic compartmentalization of infected cells. While most pronounced effects could be seen on micro- and intermediate filaments, manifest in dramatic rearrangements and degradation of filamentous (F-)actin and vimentin structures, only little impact could be seen on microtubules or the nuclear envelope during the entire monitored time of infection.more » To further analyze the disruption of the cytoskeletal structures, we investigated the viral impact on selective regulatory pathways. Thereby, we found a correlation between microtubule stability and MVM-induced phosphorylation of {alpha}/{beta} tubulin. In contrast, disassembly of actin filaments late in infection could be traced back to the disregulation of two F-actin associated proteins gelsolin and Wiscott-Aldrich Syndrome Protein (WASP). Thereby, an increase in the amount of gelsolin, an F-actin severing protein was observed during infection, accounting for the disruption of stress fibers upon infection. Concomitantly, the actin polymerization activity also diminished due to a loss of WASP, the activator protein of the actin polymerization machinery the Arp2/3 complex. No effects could be seen in amount and distribution of other F-actin regulatory factors such as cortactin, cofilin, and profilin. In summary, the selective attack of MVM towards distinct host cell cytoskeletal structures argues for a regulatory feature during infection, rather than a collapse of the host cell as a mere side effect of virus production.« less

Observing Planetary Nebulae with JWST and Extremely Large Telescopes

NASA Astrophysics Data System (ADS)

Sahai, Raghvendra

2015-01-01

Most stars in the Universe that leave the main sequence in a Hubble time will end their lives evolving through the Planetary Nebula (PN) evolutionary phase. The heavy mass loss which occurs during the preceding AGB phase is important across astrophysics, dramatically changing the course of stellar evolution, dominantly contributing to the dust content of the interstellar medium, and influencing its chemical composition. The evolution from the AGB phase to the PN phases remains poorly understood, especially the dramatic transformation that occurs in the morphology of the mass-ejecta as AGB stars and their round circumstellar envelopes evolve into mostly PNe, the majority of which deviate strongly from spherical symmetry. In addition, although the PN [OIII] luminosity function (PNLF) has been used as a standard candle (on par with distance indicators such as Cepheids), we do not understand why it works. It has been argued that the resolution of these issues may be linked to binarity and associated processes such as mass transfer and common envelope evolution.Thus, understanding the formation and evolution of PNe is of wide astrophysical importance. PNe have long been known to emit across a very large span of wavelengths, from the radio to X-rays. Extensive use of space-based observatories at X-ray (Chandra/ XMM-Newton), optical (HST) and far-infrared (Spitzer, Herschel) wavelengths in recent years has produced significant new advances in our knowledge of these objects. Given the expected advent of the James Webb Space Telescope in the near future, and ground-based Extremely Large Telescope(s) somewhat later, this talk will focus on future high-angular-resolution, high-sensitivity observations at near and mid-IR wavelengths with these facilities that can help in addressing the major unsolved problems in the study of PNe.

Sand ridge morphology and bedform migration patterns derived from bathymetry and backscatter on the inner-continental shelf offshore of Assateague Island, USA

USGS Publications Warehouse

Pendleton, Elizabeth; Brothers, Laura; Thieler, E. Robert; Sweeney, Edward

2017-01-01

The U.S. Geological Survey and the National Oceanographic and Atmospheric Administration conducted geophysical and hydrographic surveys, respectively, along the inner-continental shelf of Fenwick and Assateague Islands, Maryland and Virginia over the last 40 years. High resolution bathymetry and backscatter data derived from surveys over the last decade are used to describe the morphology and presence of sand ridges on the inner-continental shelf and measure the change in the position of smaller-scale (10–100 s of meters) seafloor features. Bathymetric surveys from the last 30 years link decadal-scale sand ridge migration patterns to the high-resolution measurements of smaller-scale bedform features. Sand ridge morphology on the inner-shelf changes across-shore and alongshore. Areas of similar sand ridge morphology are separated alongshore by zones where ridges are less pronounced or completely transected by transverse dunes. Seafloor-change analyses derived from backscatter data over a 4–7 year period show that southerly dune migration increases in magnitude from north to south, and the east-west pattern of bedform migration changes ~ 10 km north of the Maryland-Virginia state line. Sand ridge morphology and occurrence and bedform migration changes may be connected to observed changes in geologic framework including topographic highs, deflated zones, and sand availability. Additionally, changes in sand ridge occurrence and morphology may help explain changes in the long-term shoreline trends along Fenwick and Assateague Islands. Although the data presented here cannot quantitatively link sand ridges to sediment transport and shoreline change, it does present a compelling relationship between inner-shelf sand availability and movement, sand ridge occurrence and morphology, geologic framework, and shoreline behavior.

Sand ridge morphology and bedform migration patterns derived from bathymetry and backscatter on the inner-continental shelf offshore of Assateague Island, USA

NASA Astrophysics Data System (ADS)

Pendleton, Elizabeth A.; Brothers, Laura L.; Thieler, E. Robert; Sweeney, Edward M.

2017-07-01

The U.S. Geological Survey and the National Oceanographic and Atmospheric Administration conducted geophysical and hydrographic surveys, respectively, along the inner-continental shelf of Fenwick and Assateague Islands, Maryland and Virginia over the last 40 years. High resolution bathymetry and backscatter data derived from surveys over the last decade are used to describe the morphology and presence of sand ridges on the inner-continental shelf and measure the change in the position of smaller-scale (10-100 s of meters) seafloor features. Bathymetric surveys from the last 30 years link decadal-scale sand ridge migration patterns to the high-resolution measurements of smaller-scale bedform features. Sand ridge morphology on the inner-shelf changes across-shore and alongshore. Areas of similar sand ridge morphology are separated alongshore by zones where ridges are less pronounced or completely transected by transverse dunes. Seafloor-change analyses derived from backscatter data over a 4-7 year period show that southerly dune migration increases in magnitude from north to south, and the east-west pattern of bedform migration changes 10 km north of the Maryland-Virginia state line. Sand ridge morphology and occurrence and bedform migration changes may be connected to observed changes in geologic framework including topographic highs, deflated zones, and sand availability. Additionally, changes in sand ridge occurrence and morphology may help explain changes in the long-term shoreline trends along Fenwick and Assateague Islands. Although the data presented here cannot quantitatively link sand ridges to sediment transport and shoreline change, it does present a compelling relationship between inner-shelf sand availability and movement, sand ridge occurrence and morphology, geologic framework, and shoreline behavior.

Japan's Democracy: How Much Change? Headline Series No. 305.

ERIC Educational Resources Information Center

Krauss, Ellis S.

This booklet analyzes the changes that have occurred in Japan in the postwar period. The book is divided into four chapters. Chapter 1, "Revolutionary Change: American Occupation, 1945-52," focuses on the dramatic changes brought by Occupation forces. Chapter 2, "Evolutionary Change: Japan's Democracy from the Occupation through the…

Some guidelines for helping natural resources adapt to climate change

Treesearch

Jill S. Baron; Susan Herrod Julius; Jordan M. West; Linda A. Joyce; Geoffrey Blate; Charles H. Peterson; Margaret Palmer; Brian D. Keller; Peter Kareiva; J. Michael Scott; Brad Griffith

2008-01-01

The changes occurring in mountain regions are an epitome of climate change. The dramatic shrinkage of major glaciers over the past century - and especially in the last 30 years - is one of several iconic images that have come to symbolize climate change.

Climate change damages to Alaska public infrastructure and the economics of proactive adaptation

EPA Science Inventory

Climate change in the circumpolar region is causing dramatic environmental change that increases the vulnerability of the built environment. We quantified the economic impacts of climate change on Alaska’s public infrastructure under relatively high and low climate forcing scenar...

The relative importance of body size and paleoclimatic change as explanatory variables influencing lineage diversification rate: an evolutionary analysis of bullhead catfishes (Siluriformes: Ictaluridae).

PubMed

Hardman, Michael; Hardman, Lotta M

2008-02-01

We applied Bayesian phylogenetics, divergence time estimation, diversification pattern analysis, and parsimony-based methods of ancestral state reconstruction to a combination of nucleotide sequences, maximum body sizes, fossils, and paleoclimate data to explore the influence of an extrinsic (climate change) and an intrinsic (maximum body size) factor on diversification rates in a North American clade of catfishes (Ictaluridae). We found diversification rate to have been significantly variable over time, with significant (or nearly significant) rate increases in the early history of Noturus. Though the latter coincided closely with a period of dramatic climate change at the Eocene-Oligocene boundary, we did not detect evidence for a general association between climate change and diversification rate during the entire history of Ictaluridae. Within Ictaluridae, small body size was found to be a near significant predictor of species richness. Morphological stasis of several species appears to be a consequence of a homoplastic increase in body size. We estimated the maximum standard length of the ictalurid ancestor to be approximately 50 cm, comparable to Eocene ictalurids (Astephus) and similar to modern sizes of Ameiurus and their Asian sister-taxon Cranoglanis. During the late Paleocene and early Eocene, the ictalurid ancestor diversified into the lineages represented by the modern epigean genera. The majority of modern species originated in the Oligocene and Miocene, most likely according to a peripheral isolates model of speciation. We discuss the difficulties of detecting macroevolutionary patterns within a lineage history and encourage the scrutiny of the terminal Eocene climatic event as a direct promoter of diversification.

The impacts of Cenozoic climate and habitat changes on small mammal diversity of North America

NASA Astrophysics Data System (ADS)

Samuels, Joshua X.; Hopkins, Samantha S. B.

2017-02-01

Through the Cenozoic, paleoclimate records show general trends of global cooling and increased aridity, and environments in North America shifted from predominantly forests to more open habitats. Paleobotanical records indicate grasses were present on the continent in the Eocene; however, paleosol and phytolith studies indicate that open habitats did not arise until the late Eocene or even later in the Oligocene. Studies of large mammalian herbivores have documented changes in ecomorphology and community structure through time, revealing that shifts in mammalian morphology occurred millions of years after the environmental changes thought to have triggered them. Smaller mammals, like rodents and lagomorphs, should more closely track climate and habitat changes due to their shorter generation times and smaller ranges, but these animals have received much less study. To examine changes in smaller mammals through time, we have assembled and analyzed an ecomorphological database of all North American rodent and lagomorph species. Analyses of these data found that rodent and lagomorph community structure changed dramatically through the Cenozoic, and shifts in diversity and ecology correspond closely with the timing of habitat changes. Cenozoic rodent and lagomorph species diversity is strongly biased by sampling of localities, but sampling-corrected diversity reveals diversity dynamics that, after an initial density-dependent diversification in the Eocene, track habitat changes and the appearance of new ecological adaptations. As habitats became more open and arid through time, rodent and lagomorph crown heights increased while burrowing, jumping, and cursorial adaptations became more prevalent. Through time, open-habitat specialists were added during periods of diversification, while closed-habitat taxa were disproportionately lost in subsequent diversity declines. While shifts among rodents and lagomorphs parallel changes in ungulate communities, they started millions of years earlier than in larger mammals. This is likely a consequence of the smaller mammals' greater sensitivity to environmental changes and more rapid evolution. These results highlight the importance of examining understudied members of vertebrate faunas for understanding the evolution of terrestrial communities through time.

Overexpression of plum auxin receptor PslTIR1 in tomato alters plant growth, fruit development and fruit shelf-life characteristics.

PubMed

El-Sharkawy, I; Sherif, S; El Kayal, W; Jones, B; Li, Z; Sullivan, A J; Jayasankar, Subramanian

2016-02-29

TIR1-like proteins are F-box auxin receptors. Auxin binding to the F-box receptor proteins promotes the formation of SCF(TIR1) ubiquitin ligase complex that targets the auxin repressors, Aux/IAAs, for degradation via the ubiquitin/26S proteasome pathway. The release of auxin response factors (ARFs) from their Aux/IAA partners allows ARFs to mediate auxin-responsive changes in downstream gene transcription. In an attempt to understand the potential role of auxin during fruit development, a plum auxin receptor, PslTIR1, has previously been characterized at the cellular, biochemical and molecular levels, but the biological significance of this protein is still lacking. In the present study, tomato (Solanum lycopersicum) was used as a model to investigate the phenotypic and molecular changes associated with the overexpression of PslTIR1. The findings of the present study highlighted the critical role of PslTIR1 as positive regulator of auxin-signalling in coordinating the development of leaves and fruits. This was manifested by the entire leaf morphology of transgenic tomato plants compared to the wild-type compound leaf patterning. Moreover, transgenic plants produced parthenocarpic fruits, a characteristic property of auxin hypersensitivity. The autocatalytic ethylene production associated with the ripening of climacteric fruits was not significantly altered in transgenic tomato fruits. Nevertheless, the fruit shelf-life characteristics were affected by transgene presence, mainly through enhancing fruit softening rate. The short shelf-life of transgenic tomatoes was associated with dramatic upregulation of several genes encoding proteins involved in cell-wall degradation, which determine fruit softening and subsequent fruit shelf-life. The present study sheds light into the involvement of PslTIR1 in regulating leaf morphology, fruit development and fruit softening-associated ripening, but not autocatalytic ethylene production. The results demonstrate that auxin accelerates fruit softening independently of ethylene action and this is probably mediated through the upregulation of many cell-wall metabolism genes.

A Temperature-Responsive Network Links Cell Shape and Virulence Traits in a Primary Fungal Pathogen

PubMed Central

Beyhan, Sinem; Gutierrez, Matias; Voorhies, Mark; Sil, Anita

2013-01-01

Survival at host temperature is a critical trait for pathogenic microbes of humans. Thermally dimorphic fungal pathogens, including Histoplasma capsulatum, are soil fungi that undergo dramatic changes in cell shape and virulence gene expression in response to host temperature. How these organisms link changes in temperature to both morphologic development and expression of virulence traits is unknown. Here we elucidate a temperature-responsive transcriptional network in H. capsulatum, which switches from a filamentous form in the environment to a pathogenic yeast form at body temperature. The circuit is driven by three highly conserved factors, Ryp1, Ryp2, and Ryp3, that are required for yeast-phase growth at 37°C. Ryp factors belong to distinct families of proteins that control developmental transitions in fungi: Ryp1 is a member of the WOPR family of transcription factors, and Ryp2 and Ryp3 are both members of the Velvet family of proteins whose molecular function is unknown. Here we provide the first evidence that these WOPR and Velvet proteins interact, and that Velvet proteins associate with DNA to drive gene expression. Using genome-wide chromatin immunoprecipitation studies, we determine that Ryp1, Ryp2, and Ryp3 associate with a large common set of genomic loci that includes known virulence genes, indicating that the Ryp factors directly control genes required for pathogenicity in addition to their role in regulating cell morphology. We further dissect the Ryp regulatory circuit by determining that a fourth transcription factor, which we name Ryp4, is required for yeast-phase growth and gene expression, associates with DNA, and displays interdependent regulation with Ryp1, Ryp2, and Ryp3. Finally, we define cis-acting motifs that recruit the Ryp factors to their interwoven network of temperature-responsive target genes. Taken together, our results reveal a positive feedback circuit that directs a broad transcriptional switch between environmental and pathogenic states in response to temperature. PMID:23935449

Effect of intermittent shear stress on corneal epithelial cells using an in vitro flow culture model.

PubMed

Hampel, Ulrike; Garreis, Fabian; Burgemeister, Fabian; Eßel, Nicole; Paulsen, Friedrich

2018-04-27

The aim of this study was to establish and to evaluate an in vitro model for culturing human telomerase-immortalized corneal epithelial (hTCEpi) cells under adjustable medium flow mimicking the movements of the tear film on the ocular surface. Using an IBIDI pump system, cells were cultured under unidirectional, continuous or oscillating, discontinuous medium flow. Cell surface and cytoskeletal architecture were investigated by scanning electron microscopy and immunofluorescence. Gene expression of e-cadherin, occludin, tight junction protein (TJP), desmoplakin, desmocollin and mucins was investigated by real-time PCR. Protein expression of desmoplakin, TJP, occludin and e-cadherin was analyzed by western blot and localization was detected by immunofluorescence. Rose bengal staining was used to assess mucin (MUC) barrier integrity. MUC1, -4 and -16 proteins were localized by immunofluorescence. Medium flow-induced shear stress dramatically changed cellular morphology of hTCEpi. Cells subjected to discontinuous shear stress displayed the typical flattened, polygonal cell shape of the superficial layer of stratified squamous epithelia. Cell surfaces showed less bulging under shear stress and less extracellular gaps. The mRNA expression of E-cadherin, occludin and TJP were increased under oscillatory medium flow. Desmoplakin and occludin protein were upregulated under oscillatory shear stress. Stress fiber formation was not aligned to flow direction. MUC1, -4, and -16 protein were localized under all culture conditions, a regulation on mRNA expression was not detectable. Rose Bengal uptake was diminished under unidirectional conditions. Our findings suggest that shear stress as it occurs at the ocular surface during blinking exerts marked effects on corneal epithelial cells, such as changes in cellular morphology and expression of cell junctions. The described model may be useful for in vitro investigations of ocular surface epithelia as it represents a much more physiologic reproduction of the in vivo situation than the commonly applied static culture conditions. Copyright © 2018. Published by Elsevier Inc.

Influence of organophosphate poisoning on human dendritic cells.

PubMed

Schäfer, Marina; Koppe, Franziska; Stenger, Bernhard; Brochhausen, Christoph; Schmidt, Annette; Steinritz, Dirk; Thiermann, Horst; Kirkpatrick, Charles James; Pohl, Christine

2013-12-05

Organophosphourus compounds (OPC, including nerve agents and pesticides) exhibit acute toxicity by inhibition of acetylcholinesterase. Lung affections are frequent complications and a risk factor for death. In addition, epidemiological studies reported immunological alterations after OPC exposure. In our experiments we investigated the effects of organophosphourus pesticides dimethoate and chlorpyrifos on dendritic cells (DC) that are essential for the initial immune response, especially in the pulmonary system. DC, differentiated from the monocyte cell line THP-1 by using various cytokines (IL-4, GM-CSF, TNF-α, Ionomycin), were exposed to organophosphourus compounds at different concentrations for a 24h time period. DC were characterized by flow cytometry and immunofluorescence using typical dendritic cell markers (e.g., CD11c, CD209 and CD83). After OPC exposure we investigated cell death, the secretion profile of inflammatory mediators, changes of DC morphology, and the effect on protein kinase signalling pathways. Our results revealed a successful differentiation of THP-1 into DC. OPC exposure caused a significant concentration-dependent influence on DC: Dendrites of the DC were shortened and damaged, DC-specific cell surface markers (i.e., CD83and CD209) decreased dramatically after chlorpyrifos exposure. Interestingly, the effects caused by dimethoate were in general less pronounced. The organophosphourus compounds affected the release of inflammatory cytokines, such as IL-1ß and IL-8. The anti-inflammatory cytokine IL-10 was significantly down regulated. Protein kinases like the Akt family or ERK, which are essential for cell survival and proliferation, were inhibited by both OPC. These findings indicate that the tested organophosphourus compounds induced significant changes in cell morphology, inhibited anti-inflammatory cytokines and influenced important protein signalling pathways which are involved in regulation of apoptosis. Thus our results highlight novel aspects -apparently independent of AChE inhibition- of OPC poisoning with regard to lung toxicity. Our findings contribute to the basic understanding of pulmonary complications caused by OPC poisoning. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Changes in corneal epithelial layer inflammatory cells in aqueous tear-deficient dry eye.

PubMed

Lin, Hui; Li, Wei; Dong, Nuo; Chen, Wensheng; Liu, Jing; Chen, Lelei; Yuan, Hongxia; Geng, Zhixin; Liu, Zuguo

2010-01-01

To investigate the morphology, distribution, and density of inflammatory cells in the corneal epithelium of aqueous tear-deficient dry eye. Thirty-two patients with non-Sjögren's syndrome (NSS) dry eye, 14 patients with Sjögren's syndrome (SS) dry eye, and 33 healthy volunteers were studied. In vivo laser scanning confocal microscopy was used to investigate both Langerhans cell (LCs) and leukocyte distribution and density in the peripheral and central corneal epithelium. LC morphology was also evaluated. Multifactor regression analysis assessed whether there is a correlation between clinical manifestations and inflammatory cell densities. LCs were present in both central (34.9 +/- 5.7 cells/mm(2)) and peripheral (90.7 +/- 8.2 cells/mm(2)) parts of the normal corneal epithelium. Moreover, LC density increased dramatically in the central corneal epithelium in patients with NSS (89.8 +/- 10.8 cells/mm(2)) and SS (127.9 +/- 23.7 cells/mm(2)). The ratio of LCs with obvious processes was much higher in patients with dry eye than in healthy volunteers. LC density also increased in peripheral corneal epithelium in patients with SS, but not in those with NSS. Leukocyte density in normal corneal epithelium was very low, whereas it increased in the central corneal epithelium (4.6 +/- 1.0 cells/mm(2)) in NSS and in both central (49.0 +/- 12.9 cells/mm(2)) and peripheral (84.2 +/- 36.8 cells/mm(2)) corneal epithelium in SS. Densities of LCs and leukocytes showed significant correlation with the severity found in clinical evaluation. The LC and leukocyte changes in the corneal epithelium suggest their involvement in aqueous tear-deficient dry eye pathophysiology. In vivo dynamic assessment of central corneal inflammatory cell density may serve as an indicator of dry eye severity and provide new insight for dry eye treatment.

Insect symbiosis: derivation of yeast-like endosymbionts within an entomopathogenic filamentous lineage.

PubMed

Suh, S O; Noda, H; Blackwell, M

2001-06-01

Yeast-like endosymbionts (YLSs) of insects often are restricted to specific hosts and are essential to the host's survival. For example, in planthoppers (Homoptera: Delphacidae), endosymbionts function in sterol utilization and nitrogen recycling for the hosts. Our study, designed to investigate evolutionary changes in the YLS lineage involved in the planthopper association, strongly suggests an origin of the YLSs from within the filamentous ascomycetes (Euascomycetes), not the true yeasts (Saccharomycetes), as their morphology might indicate. During divergence of the planthopper YLSs, dramatic changes would have occurred in the insect-fungus interaction and the fungal morphology that have previously been undescribed in filamentous ascomycetes. Phylogenetic trees were based on individual and combined data sets of 2.6 kb of the nuclear small- and large-subunit ribosomal RNA genes for YLSs from three rice planthoppers (Laodelphax striatellus, Nilaparvata lugens, and Sogatella furcifera) compared with 56 other fungi. Parsimony analysis placed the planthopper YLSs within Cordyceps (Euascomycetes: Hypocreales: Clavicipitaceae), a genus of filamentous insects and a few fungal pathogenic ascomycetes. Another YLS species restricted to the aphid Hamiltonaphis styraci (Homoptera: Aphididae) was a sister taxon to the planthopper YLSS: Filamentous insect pathogens (Metarhizium and Beauveria) specific to the same species of insect hosts as the YLSs also formed lineages within the Clavicipitaceae, but these were distinct from the clade comprising YLS species. Trees constrained to include the YLSs in families of the Hypocreales other than the Clavicipitaceae were rejected by the Kishino-Hasegawa test. In addition, the results of this study support a hypothesis of two independent origins of insect-associated YLSs from among filamentous ascomycetes: the planthopper YLSs in the Clavicipitaceae and the YLSs associated with anobiid beetles (Symbiotaphrina species). Several lineages of true yeasts (Saccharomycetes) also formed endosymbiotic associations with beetles, but they were not closely related to either group derived from the filamentous ascomycetes.

A functional interplay between the small GTPase Rab11a and mitochondria-shaping proteins regulates mitochondrial positioning and polarization of the actin cytoskeleton downstream of Src family kinases.

PubMed

Landry, Marie-Claude; Champagne, Claudia; Boulanger, Marie-Chloé; Jetté, Alexandra; Fuchs, Margit; Dziengelewski, Claire; Lavoie, Josée N

2014-01-24

It is believed that mitochondrial dynamics is coordinated with endosomal traffic rates during cytoskeletal remodeling, but the mechanisms involved are largely unknown. The adenovirus early region 4 ORF4 protein (E4orf4) subverts signaling by Src family kinases (SFK) to perturb cellular morphology, membrane traffic, and organellar dynamics and to trigger cell death. Using E4orf4 as a model, we uncovered a functional connection between mitochondria-shaping proteins and the small GTPase Rab11a, a key regulator of polarized transport via recycling endosomes. We found that E4orf4 induced dramatic changes in the morphology of mitochondria along with their mobilization at the vicinity of a polarized actin network typifying E4orf4 action, in a manner controlled by SFK and Rab11a. Mitochondrial remodeling was associated with increased proximity between Rab11a and mitochondrial membranes, changes in fusion-fission dynamics, and mitochondrial relocalization of the fission factor dynamin-related protein 1 (Drp1), which was regulated by the Rab11a effector protein FIP1/RCP. Knockdown of FIP1/RCP or inhibition of Drp1 markedly impaired mitochondrial remodeling and actin assembly, involving Rab11a-mediated mitochondrial dynamics in E4orf4-induced signaling. A similar mobilization of mitochondria near actin-rich structures was mediated by Rab11 and Drp1 in viral Src-transformed cells and contributed to the biogenesis of podosome rosettes. These findings suggest a role for Rab11a in the trafficking of Drp1 to mitochondria upon SFK activation and unravel a novel functional interplay between Rab11a and mitochondria during reshaping of the cell cytoskeleton, which would facilitate mitochondria redistribution near energy-requiring actin-rich structures.

[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.

Mid-infrared Variability of Changing-look AGNs

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

Sheng, Zhenfeng; Wang, Tinggui; Jiang, Ning

2017-09-01

It is known that some active galactic nuclei (AGNs) transit from Type 1 to Type 2 or vice versa. There are two explanations for the so-called changing-look AGNs: one is the dramatic change of the obscuration along the line of sight, and the other is the variation of accretion rate. In this Letter, we report the detection of large amplitude variations in the mid-infrared luminosity during the transitions in 10 changing-look AGNs using the Wide-field Infrared Survey Explorer ( WISE ) and newly released Near-Earth Object WISE Reactivation data. The mid-infrared light curves of 10 objects echo the variability inmore » the optical band with a time lag expected for dust reprocessing. The large variability amplitude is inconsistent with the scenario of varying obscuration, rather it supports the scheme of dramatic change in the accretion rate.« less

Morphogenesis and three-dimensional movement of the stomach during the human embryonic period.

PubMed

Kaigai, N; Nako, A; Yamada, S; Uwabe, C; Kose, K; Takakuwa, T

2014-05-01

The stomach develops as the local widening of the foregut after Carnegie stage (CS) 13 that moves in a dramatic and dynamic manner during the embryonic period. Using the magnetic resonance images of 377 human embryos, we present the morphology, morphometry, and three-dimensional movement of the stomach during CS16 and CS23. The stomach morphology revealed stage-specific features. The angular incisura and the cardia were formed at CS18. The change in the angular incisura angle was approximately 90° during CS19 and CS20, and was <90° after CS 21. The prominent formations of the fundus and the pylorus differentiate at around CS20. Morphometry of the stomach revealed that the stomach gradually becomes "deflected" during development. The stomach may appear to move to the left laterally and caudally due to its deflection and differential growth. The track of the reference points in the stomach may reflect the visual three-dimensional movement. The movement of point M, representing the movement of the greater curvature, was different from that of points C (cardia) and P (pyloric antrum). The P and C were located just around the midsagittal plane in all the stages observed. Point M moved in the caudal-left lateral direction until CS22. Moreover, the vector CP does not rotate around the dorsoventral axis, as widely believed, but around the transverse axis. The plane CPM rotated mainly around the longitudinal axis. The data obtained will be useful for prenatal diagnosis in the near future. Copyright © 2013 Wiley Periodicals, Inc.

Different cell death pathways induced by drugs in Trypanosoma cruzi: an ultrastructural study.

PubMed

Menna-Barreto, Rubem F S; Salomão, Kelly; Dantas, Andréia P; Santa-Rita, Ricardo M; Soares, Maurilio J; Barbosa, Helene S; de Castro, Solange L

2009-02-01

Electron microscopy has proven to be a reliable and essential tool to determine morphological alterations and target organelles in the investigation of new drugs for Chagas disease. In this review, we focused on evaluating different agents that induce death of Trypanosoma cruzi, i.e. lysophospholipids analogues, naphthoquinones and derivatives, cytoskeletal inhibitors and natural products. Apoptosis-like presents as morphological characteristics DNA fragmentation, membrane blebbing and apoptotic body formation. Autophagy involves autophagosome formation, with the appearance of membranes surrounding organelles and cytosolic structures. Necrosis causes the loss of osmotic balance, an increase of cytoplasmic vacuolization and plasma membrane disruption. Mitochondrion appears as a central checkpoint in both apoptosis and necrosis. Our evidences of ultrastructural changes to T. cruzi treated with the different classes of compounds point to dramatic mitochondrial alterations and similar autophagic phenotypes. Lysophospholipid analogues interfere in the lipid biosynthesis in epimastigotes, altering the amount of both phospholipids and sterols, and consequently the physical properties of the membrane. Naphthoquinone derivatives led to a strong DNA fragmentation in trypomastigotes and to the release of cysteine proteases from reservosomes to cytosol in epimastigotes, starting a proteolytic process which results in parasite death. The susceptibility of reservosomes was also observed in parasites treated with propolis, suggesting impairment of lipid metabolism, compromising membrane fluidity and leading to lysis. The cytoskeletal agents blocked mitosis of epimastigotes, arresting cell cycle and impairing the parasite proliferation. The variety of drug stimuli converge to the same pathway of death suggests an intense cross-talking between the three types of PCD in the protozoa.

Biocompatibility of Synthetic Poly(ester urethane)/Polyhedral Oligomeric Silsesquioxane Matrices with Embryonic Stem Cell Proliferation and Differentiation

PubMed Central

Guo, Yan-Lin; Wang, Wenshou; Otaigbe, Joshua U.

2010-01-01

Incorporation of polyhedral oligomeric silsesquioxanes (POSS) into poly (ester urethane)s (PEU) as a building block results in a PEU/POSS hybrid polymer with increased mechanical strength and thermostability. An attractive feature of the new polymer is that it forms a porous matrix when cast in the form of a thin film, making it potentially useful in tissue engineering. In this study, we present detailed microscopic analysis of the PEU/POSS matrix and demonstrate its biocompatibility with cell culture. The PEU/POSS polymer forms a continuous porous matrix with open pores and interconnected grooves. From SEM image analysis, it is calculated that there are about 950 pores per mm2 of the matrix area with pore size ranging from 1 to 15 μm in diameter. The area occupied by the pores represents approximately 7.6 % of matrix area. Using mouse embryonic stem cells (ESCs), we demonstrate that the PEU/POSS matrix provides excellent support for cell proliferation and differentiation. Under the cell culture condition optimized to maintain self-renewal, ESCs grown on a PEU/POSS matrix exhibit undifferentiated morphology, express pluripotency markers, and have similar growth rate to cells grown on gelatin. When induced for differentiation, ESCs underwent dramatic morphological change, characterized by the loss of clonogenecity and increased cell size with well-expanded cytoskeleton networks. Differentiated cells are able to form a continuous monolayer that is closely embedded on the matrix. The excellent compatibility between the PEU/POSS matrix and ESC proliferation/differentiation demonstrates the potential of using PEU/POSS polymers in future ESC-based tissue engineering. PMID:20213627

Edaravone Protects against Methylglyoxal-Induced Barrier Damage in Human Brain Endothelial Cells

PubMed Central

Tóth, Andrea E.; Walter, Fruzsina R.; Bocsik, Alexandra; Sántha, Petra; Veszelka, Szilvia; Nagy, Lajos; Puskás, László G.; Couraud, Pierre-Olivier; Takata, Fuyuko; Dohgu, Shinya; Kataoka, Yasufumi; Deli, Mária A.

2014-01-01

Background Elevated level of reactive carbonyl species, such as methylglyoxal, triggers carbonyl stress and activates a series of inflammatory responses leading to accelerated vascular damage. Edaravone is the active substance of a Japanese medicine, which aids neurological recovery following acute brain ischemia and subsequent cerebral infarction. Our aim was to test whether edaravone can exert a protective effect on the barrier properties of human brain endothelial cells (hCMEC/D3 cell line) treated with methylglyoxal. Methodology Cell viability was monitored in real-time by impedance-based cell electronic sensing. The barrier function of the monolayer was characterized by measurement of resistance and flux of permeability markers, and visualized by immunohistochemistry for claudin-5 and β-catenin. Cell morphology was also examined by holographic phase imaging. Principal Findings Methylglyoxal exerted a time- and dose-dependent toxicity on cultured human brain endothelial cells: a concentration of 600 µM resulted in about 50% toxicity, significantly reduced the integrity and increased the permeability of the barrier. The cell morphology also changed dramatically: the area of cells decreased, their optical height significantly increased. Edaravone (3 mM) provided a complete protection against the toxic effect of methylglyoxal. Co-administration of edaravone restored cell viability, barrier integrity and functions of brain endothelial cells. Similar protection was obtained by the well-known antiglycating molecule, aminoguanidine, our reference compound. Conclusion These results indicate for the first time that edaravone is protective in carbonyl stress induced barrier damage. Our data may contribute to the development of compounds to treat brain endothelial dysfunction in carbonyl stress related diseases. PMID:25033388

Anomalous absorption of isolated silver nanoparticulate films in visible region of electromagnetic field.

PubMed

Kim, Sang Woo; Hui, Bang Jae; Bae, Dong-Sik

2008-02-01

Anomalous absorption of isolated silver nanoparticulate films with different morphological patterns prepared by the wet colloidal route and followed by thermal treatment were investigated. A polymer embedded silver nanoparticulate film thermally treated at 200 degrees C showed maximum absorbance at approximately 412 nm. The peak position of the surface plasmon band was slightly different but still consistent with theoretical prediction derived by the Mie theory. An isolated nanopariculate film thermally treated at 300 degrees C showed anomalous absorption. Its maximum absorption band was shifted to green regime of 506.9 nm and the bandwidth at half-maximum absorbance of the surface plasmon band was greatly broadened. The plasmon band and its bandwidth were much deviated compared to the theoretical prediction calculated for the silver nanoparticles in the surrounding medium of air and poly(vinyl pyrrolidone) or soda-lime-silica glass. Even though there was no significant growth of silver nanoparticles during thermal treatment at 300 degrees C, the anomalous absorption was observed. The anomalous absorption was not attributed to effects of particle shape and size but to effects of pores induced by development of a great number of pores in the nanoparticulate film. The anomalous absorption greatly decreased with increase in heating temperature from 400 degrees C to 500 degrees C. The extraordinary plasmon damping of the isolated film decreased and the plasmon absorption band was re-shifted to violet regime of 416 nm because of large decrease in size of particles with dramatic change of pore morphology from circular pores with rim to small continuous pores induced by spontaneous formation of new silver nanoparticles.

Nanoscale Effects of Caspofungin against Two Yeast Species, Saccharomyces cerevisiae and Candida albicans

PubMed Central

Formosa, C.; Schiavone, M.; Martin-Yken, H.; François, J. M.; Duval, R. E.

2013-01-01

Saccharomyces cerevisiae and Candida albicans are model yeasts for biotechnology and human health, respectively. We used atomic force microscopy (AFM) to explore the effects of caspofungin, an antifungal drug used in hospitals, on these two species. Our nanoscale investigation revealed similar, but also different, behaviors of the two yeasts in response to treatment with the drug. While administration of caspofungin induced deep cell wall remodeling in both yeast species, as evidenced by a dramatic increase in chitin and decrease in β-glucan content, changes in cell wall composition were more pronounced with C. albicans cells. Notably, the increase of chitin was proportional to the increase in the caspofungin dose. In addition, the Young modulus of the cell was three times lower for C. albicans cells than for S. cerevisiae cells and increased proportionally with the increase of chitin, suggesting differences in the molecular organization of the cell wall between the two yeast species. Also, at a low dose of caspofungin (i.e., 0.5× MIC), the cell surface of C. albicans exhibited a morphology that was reminiscent of cells expressing adhesion proteins. Interestingly, this morphology was lost at high doses of the drug (i.e., 4× MIC). However, the treatment of S. cerevisiae cells with high doses of caspofungin resulted in impairment of cytokinesis. Altogether, the use of AFM for investigating the effects of antifungal drugs is relevant in nanomedicine, as it should help in understanding their mechanisms of action on fungal cells, as well as unraveling unexpected effects on cell division and fungal adhesion. PMID:23669379

Doping magnesium hydroxide with sodium nitrate: a new approach to tune the dehydration reactivity of heat-storage materials.

PubMed

Shkatulov, Alexandr; Krieger, Tamara; Zaikovskii, Vladimir; Chesalov, Yurii; Aristov, Yuri

2014-11-26

Thermochemical energy storage (TES) provides a challenging approach for improving the efficiency of various energy systems. Magnesium hydroxide, Mg(OH)2, is known as a suitable material for TES at temperature T>300 °C. In this work, the thermal decomposition of Mg(OH)2 in the absence and presence of sodium nitrate (NaNO3) is investigated to adapt this material for TES at T<300 °C. The most notable observations described for the doped Mg(OH)2 are (1) a significant reduction of the decomposition temperature Td that allows tuning the dehydration reactivity by varying the NaNO3 content. The Td decrease by 25 °C is revealed at a salt content Y≤2.0 wt %. The maximum Td depression of some 50 °C is observed at Y=15-20 wt %; (2) the NaNO3-doped Mg(OH)2 decomposes considerably faster under conditions typical for closed TES cycles (at T>300 °C in vapor atmosphere) than a pure Mg(OH)2; (3) the morphology of the dehydration product (MgO) dramatically changes. Differential scanning calorimetry, high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and vibrational spectroscopy (IR and Raman) are used to study the observed effects and to elucidate possible ways the NaNO3 influences the Mg(OH)2 dehydration and morphology of the dehydration product. The mechanism involving a chemical interaction between the salt and the hydroxide accompanied by nitrate embedding into brucite layers is discussed.

A workflow for the automatic segmentation of organelles in electron microscopy image stacks

PubMed Central

Perez, Alex J.; Seyedhosseini, Mojtaba; Deerinck, Thomas J.; Bushong, Eric A.; Panda, Satchidananda; Tasdizen, Tolga; Ellisman, Mark H.

2014-01-01

Electron microscopy (EM) facilitates analysis of the form, distribution, and functional status of key organelle systems in various pathological processes, including those associated with neurodegenerative disease. Such EM data often provide important new insights into the underlying disease mechanisms. The development of more accurate and efficient methods to quantify changes in subcellular microanatomy has already proven key to understanding the pathogenesis of Parkinson's and Alzheimer's diseases, as well as glaucoma. While our ability to acquire large volumes of 3D EM data is progressing rapidly, more advanced analysis tools are needed to assist in measuring precise three-dimensional morphologies of organelles within data sets that can include hundreds to thousands of whole cells. Although new imaging instrument throughputs can exceed teravoxels of data per day, image segmentation and analysis remain significant bottlenecks to achieving quantitative descriptions of whole cell structural organellomes. Here, we present a novel method for the automatic segmentation of organelles in 3D EM image stacks. Segmentations are generated using only 2D image information, making the method suitable for anisotropic imaging techniques such as serial block-face scanning electron microscopy (SBEM). Additionally, no assumptions about 3D organelle morphology are made, ensuring the method can be easily expanded to any number of structurally and functionally diverse organelles. Following the presentation of our algorithm, we validate its performance by assessing the segmentation accuracy of different organelle targets in an example SBEM dataset and demonstrate that it can be efficiently parallelized on supercomputing resources, resulting in a dramatic reduction in runtime. PMID:25426032

Climate change and mountain-front morphology: Estimating Late Glacial to Holocene erosion rates from the shape of fault-bounded hillslopes

NASA Astrophysics Data System (ADS)

Tucker, G. E.; McCoy, S. W.; Whittaker, A. C.; Roberts, G.; Lancaster, S. T.; Phillips, R. J.

2011-12-01

The existence of well-preserved Holocene bedrock fault scarps along active normal faults in the Mediterranean region and elsewhere suggests a dramatic reduction in rates of rock weathering and erosion that correlates with the transition from glacial to interglacial climate. We test and quantify this interpretation using a case study in the Italian Central Apennines. Holocene rates are derived from measurements of weathering-pit depth along the Magnola scarp, where previous cosmogenic 36Cl analyses constrain exposure history. To estimate the average hillslope erosion rate over ˜105 years, we introduce a simple geometric model of normal-fault footwall slope evolution. The model predicts that the gradient of a weathering-limited footwall hillslope is set by fault dip angle and by the ratio of slip rate to erosion rate; if either slip or erosion rate is known, the other can be derived. Applying this model to the Magnola fault yields an estimated average weathering rate on the order of 0.2-0.4 mm/yr, more than 10x higher than either the Holocene scarp weathering rate or modern regional limestone weathering rates. A numerical model of footwall growth and erosion, in which erosion rate tracks the oxygen-isotope curve, reproduces the main features of hillslope and scarp morphology and suggests that the hillslope erosion rate has varied by about a factor of 30 over the past one to two glacial cycles. We conclude that preservation of carbonate fault scarps reflects strong climatic control on rock breakdown by frost cracking.

Generic model of morphological changes in growing colonies of fungi

NASA Astrophysics Data System (ADS)

López, Juan M.; Jensen, Henrik J.

2002-02-01

Fungal colonies are able to exhibit different morphologies depending on the environmental conditions. This allows them to cope with and adapt to external changes. When grown in solid or semisolid media the bulk of the colony is compact and several morphological transitions have been reported to occur as the external conditions are varied. Here we show how a unified simple mathematical model, which includes the effect of the accumulation of toxic metabolites, can account for the morphological changes observed. Our numerical results are in excellent agreement with experiments carried out with the fungus Aspergillus oryzae on solid agar.

The role of behaviour in adaptive morphological evolution of African proboscideans.

PubMed

Lister, Adrian M

2013-08-15

The fossil record richly illustrates the origin of morphological adaptation through time. However, our understanding of the selective forces responsible in a given case, and the role of behaviour in the process, is hindered by assumptions of synchrony between environmental change, behavioural innovation and morphological response. Here I show, from independent proxy data through a 20-million-year sequence of fossil proboscideans in East Africa, that changes in environment, diet and morphology are often significantly offset chronologically, allowing dissection of the roles of behaviour and different selective drivers. These findings point the way to hypothesis-driven testing of the interplay between habitat change, behaviour and morphological adaptation with the use of independent proxies in the fossil record.

High-precision morphology: bifocal 4D-microscopy enables the comparison of detailed cell lineages of two chordate species separated for more than 525 million years.

PubMed

Stach, Thomas; Anselmi, Chiara

2015-12-23

Understanding the evolution of divergent developmental trajectories requires detailed comparisons of embryologies at appropriate levels. Cell lineages, the accurate visualization of cleavage patterns, tissue fate restrictions, and morphogenetic movements that occur during the development of individual embryos are currently available for few disparate animal taxa, encumbering evolutionarily meaningful comparisons. Tunicates, considered to be close relatives of vertebrates, are marine invertebrates whose fossil record dates back to 525 million years ago. Life-history strategies across this subphylum are radically different, and include biphasic ascidians with free swimming larvae and a sessile adult stage, and the holoplanktonic larvaceans. Despite considerable progress, notably on the molecular level, the exact extent of evolutionary conservation and innovation during embryology remain obscure. Here, using the innovative technique of bifocal 4D-microscopy, we demonstrate exactly which characteristics in the cell lineages of the ascidian Phallusia mammillata and the larvacean Oikopleura dioica were conserved and which were altered during evolution. Our accurate cell lineage trees in combination with detailed three-dimensional representations clearly identify conserved correspondence in relative cell position, cell identity, and fate restriction in several lines from all prospective larval tissues. At the same time, we precisely pinpoint differences observable at all levels of development. These differences comprise fate restrictions, tissue types, complex morphogenetic movement patterns, numerous cases of heterochronous acceleration in the larvacean embryo, and differences in bilateral symmetry. Our results demonstrate in extraordinary detail the multitude of developmental levels amenable to evolutionary innovation, including subtle changes in the timing of fate restrictions as well as dramatic alterations in complex morphogenetic movements. We anticipate that the precise spatial and temporal cell lineage data will moreover serve as a high-precision guide to devise experimental investigations of other levels, such as molecular interactions between cells or changes in gene expression underlying the documented structural evolutionary changes. Finally, the quantitative amount of digital high-precision morphological data will enable and necessitate software-based similarity assessments as the basis of homology hypotheses.

Color and Morphology of Lava Flows on Io

NASA Astrophysics Data System (ADS)

Piatek, Jennifer L.; McElfresh, Sarah B. Z.; Byrnes, Jeffrey M.; Hale, Amy Snyder; Crown, David A.

2000-12-01

Analyses of color and morphologic changes in Voyager images of lava flows on Io were conducted to extend previous flow studies to additional volcanoes in preparation for comparison to Galileo data. Blue and orange filter images of Atar, Daedalus, and Ra Paterae were examined to identify systematic downflow decreases in blue/orange reflectivity suggested in earlier studies as diagnostic of color changes in cooled sulfur flows. Analyses of the color and morphology of 21 lava flows were conducted at these volcanoes, with additional morphologic analysis of lava flows at Agni, Masaaw, Mbali, Shoshu, and Talos Paterae. A total of 66 lava flows of up to 245 km in length were mapped to identify morphologic changes consistent with the rheologic changes expected to occur in sulfur flows. Although downflow color changes are observed, the trends are not consistent, even at the same edifice. Individual flows exhibit a statistically significant increase in blue/orange ratio, decrease in blue/orange ratio, or a lack of progressive downflow color variation. Color changes have similar magnitudes downflow and across flow, and the color ranges observed are similar from volcano to volcano, suggesting that similar processes are controlling color ratios at these edifices. In addition, using flow widening and branching as an indicator of the low viscosity exhibited by sulfur cooling from high temperatures, these flows do not exhibit morphologic changes consistent with the systematic behavior expected from the simple progressive cooling of sulfur.

Modeling the brain morphology distribution in the general aging population

NASA Astrophysics Data System (ADS)

Huizinga, W.; Poot, D. H. J.; Roshchupkin, G.; Bron, E. E.; Ikram, M. A.; Vernooij, M. W.; Rueckert, D.; Niessen, W. J.; Klein, S.

2016-03-01

Both normal aging and neurodegenerative diseases such as Alzheimer's disease cause morphological changes of the brain. To better distinguish between normal and abnormal cases, it is necessary to model changes in brain morphology owing to normal aging. To this end, we developed a method for analyzing and visualizing these changes for the entire brain morphology distribution in the general aging population. The method is applied to 1000 subjects from a large population imaging study in the elderly, from which 900 were used to train the model and 100 were used for testing. The results of the 100 test subjects show that the model generalizes to subjects outside the model population. Smooth percentile curves showing the brain morphology changes as a function of age and spatiotemporal atlases derived from the model population are publicly available via an interactive web application at agingbrain.bigr.nl.

Morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel.

PubMed

Manuela Díaz-Monroy, Jennifer; Contreras-Bulnes, Rosalía; Fernando Olea-Mejía, Oscar; Emma Rodríguez-Vilchis, Laura; Sanchez-Flores, Ignacio

2014-06-01

Several scientific reports have shown the effects of Er:YAG laser irradiation on enamel morphology. However, there is lack of information regarding the morphological alterations produced by the acid attack on the irradiated surfaces. The aim of this study was to evaluate the morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel. Forty-eight enamel samples were divided into four groups (n = 12). GI (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm(2) ), 200 mJ (25.5 J/cm(2) ), and 300 mJ (38.2 J/cm(2) ), respectively, at 10 Hz without water irrigation. Enamel morphology was evaluated before-irradiation, after-irradiation, and after-acid dissolution, by scanning electron microscopy (SEM). Sample coating was avoided and SEM analysis was performed in a low-vacuum mode. To facilitate the location of the assessment area, a reference point was marked. Morphological changes produced by acid dissolution of irradiated enamel were observed, specifically on laser-induced undesired effects. These morphological changes were from mild to severe, depending on the presence of after-irradiation undesired effects. © 2014 Wiley Periodicals, Inc.

Freezing behavior of adherent neuron-like cells and morphological change and viability of post-thaw cells.

PubMed

Uemura, Makoto; Ishiguro, Hiroshi

2015-04-01

Freezing of nerve cells forming a neuronal network has largely been neglected, despite the fact that the cryopreservation of nerve cells benefits the study of cells in the areas of medicine and poison screening. Freezing of nerve cells is also attractive for studying cell morphology because of the characteristic long, thread-like neurites extending from the cell body. In the present study, freezing of neuron-like cells adhering to the substrate (differentiated PC12 cells), in physiological saline, was investigated in order to understand the fundamental freezing and thawing characteristics of nerve cells with neurites. The microscopic freezing behavior of cells under different cooling rates was observed. Next, the post-thaw morphological changes in the cells, including the cytoskeleton, were investigated and post-thaw cell viability was evaluated by dye exclusion using propidium iodide. Two categories of morphological changes, beading and shortening of the neurites, were found and quantified. Also, the morphological changes of neurites due to osmotic stress from sodium chloride were studied to gain a better understanding of causation. The results showed that morphological changes and cell death were promoted with a decrease in end temperature during freezing. Copyright © 2015 Elsevier Inc. All rights reserved.

The antagonistic modulation of Arp2/3 activity by N-WASP, WAVE2 and PICK1 defines dynamic changes in astrocyte morphology

PubMed Central

Murk, Kai; Blanco Suarez, Elena M.; Cockbill, Louisa M. R.; Banks, Paul; Hanley, Jonathan G.

2013-01-01

Summary Astrocytes exhibit a complex, branched morphology, allowing them to functionally interact with numerous blood vessels, neighboring glial processes and neuronal elements, including synapses. They also respond to central nervous system (CNS) injury by a process known as astrogliosis, which involves morphological changes, including cell body hypertrophy and thickening of major processes. Following severe injury, astrocytes exhibit drastically reduced morphological complexity and collectively form a glial scar. The mechanistic details behind these morphological changes are unknown. Here, we investigate the regulation of the actin-nucleating Arp2/3 complex in controlling dynamic changes in astrocyte morphology. In contrast to other cell types, Arp2/3 inhibition drives the rapid expansion of astrocyte cell bodies and major processes. This intervention results in a reduced morphological complexity of astrocytes in both dissociated culture and in brain slices. We show that this expansion requires functional myosin II downstream of ROCK and RhoA. Knockdown of the Arp2/3 subunit Arp3 or the Arp2/3 activator N-WASP by siRNA also results in cell body expansion and reduced morphological complexity, whereas depleting WAVE2 specifically reduces the branching complexity of astrocyte processes. By contrast, knockdown of the Arp2/3 inhibitor PICK1 increases astrocyte branching complexity. Furthermore, astrocyte expansion induced by ischemic conditions is delayed by PICK1 knockdown or N-WASP overexpression. Our findings identify a new morphological outcome for Arp2/3 activation in restricting rather than promoting outwards movement of the plasma membrane in astrocytes. The Arp2/3 regulators PICK1, and N-WASP and WAVE2 function antagonistically to control the complexity of astrocyte branched morphology, and this mechanism underlies the morphological changes seen in astrocytes during their response to pathological insult. PMID:23843614

Adaptive significance of avian beak morphology for ectoparasite control

PubMed Central

Clayton, Dale H; Moyer, Brett R; Bush, Sarah E; Jones, Tony G; Gardiner, David W; Rhodes, Barry B; Goller, Franz

2005-01-01

The beaks of Darwin's finches and other birds are among the best known examples of adaptive evolution. Beak morphology is usually interpreted in relation to its critical role in feeding. However, the beak also plays an important role in preening, which is the first line of defence against harmful ectoparasites such as feather lice, fleas, bugs, flies, ticks and feather mites. Here, we show a feature of the beak specifically adapted for ectoparasite control. Experimental trimming of the tiny (1–2 mm) maxillary overhang of rock pigeons (Columba livia) had no effect on feeding efficiency, yet triggered a dramatic increase in feather lice and the feather damage they cause. The overhang functions by generating a shearing force against the tip of the lower mandible, which moves forward remarkably quickly during preening, at up to 31 times per second. This force damages parasite exoskeletons, significantly enhancing the efficiency of preening for parasite control. Overhangs longer than the natural mean of 1.6 mm break significantly more often than short overhangs. Hence, stabilizing selection will favour overhangs of intermediate length. The adaptive radiation of beak morphology should be re-assessed with both feeding and preening in mind. PMID:15888414

Novel cell-biological ideas deducible from morphological observations on "dark" neurons revisited.

PubMed

Gallyas, Ferenc

2007-05-30

The origin, nature and fate of "dark" (dramatically shrunken and hyperbasophilic) neurons are century-old problems in both human and experimental neuropathology. Until a few years ago, hardly any cell-biological conclusion had been drawn from their histological investigation. On the basis of light and electron microscopic findings in animal experiments performed during the past few years, my research team has put forward novel ideas concerning 1. the nature of "dark" neurons (malfunction of an energy-storing gel-structure that is ubiquitously present in all intracellular spaces between the ultrastructural elements), 2. the mechanism of their formation (non-programmed initiation of a whole-cell phase-transition in this gel-structure), 3. their capability of recovery (programmed for some physiological purpose), 4. their death mode (neither necrotic nor apoptotic), and 5. their relationship with the apoptotic cell death (the gel structure in question is programmed for the morphological execution of ontogenetic apoptosis). Based on morphological observations, this paper revisits these ideas in order to bring them to the attention of researchers who are in a position to investigate their validity by means of experimental paradigms other than those used here.

Potent Nematicidal Activity and New Hybrid Metabolite Production by Disruption of a Cytochrome P450 Gene Involved in the Biosynthesis of Morphological Regulatory Arthrosporols in Nematode-Trapping Fungus Arthrobotrys oligospora.

PubMed

Song, Tian-Yang; Xu, Zi-Fei; Chen, Yong-Hong; Ding, Qiu-Yan; Sun, Yu-Rong; Miao, Yang; Zhang, Ke-Qin; Niu, Xue-Mei

2017-05-24

Types of polyketide synthase-terpenoid synthase (PKS-TPS) hybrid metabolites, including arthrosporols with significant morphological regulatory activity, have been elucidated from nematode-trapping fungus Arthrobotrys oligospora. A previous study suggested that the gene cluster AOL_s00215 in A. oligospora was involved in the production of arthrosporols. Here, we report that disruption of one cytochrome P450 monooxygenase gene AOL_s00215g280 in the cluster resulted in significant phenotypic difference and much aerial hyphae. A further bioassay indicated that the mutant showed a dramatic decrease in the conidial formation but developed numerous traps and killed 85% nematodes within 6 h in contact with prey, in sharp contrast to the wild-type strain with no obvious response. Chemical investigation revealed huge accumulation of three new PKS-TPS epoxycyclohexone derivatives with different oxygenated patterns around the epoxycyclohexone moiety and the absence of arthrosporols in the cultural broth of the mutant ΔAOL_s00215g280. These findings suggested that a study on the biosynthetic pathway for morphological regulatory metabolites in nematode-trapping fungus would provide an efficient way to develop new fungal biocontrol agents.

Optical redox ratio differentiates early tissue transformations in DMBA-induced hamster oral carcinogenesis based on autofluorescence spectroscopy coupled with multivariate analysis

NASA Astrophysics Data System (ADS)

Sethupathi, R.; Gurushankar, K.; Krishnakumar, N.

2016-11-01

Fluorescence intensity measurements have the potential to facilitate the diagnoses of many pathological conditions. The changes in fluorescence intensity may be influenced by factors such as tissue architectures, endogenous fluorophores, cellular metabolism and light penetration depth in tissue. Two of the most diagnostically important endogenous fluorophores are reduced nicotinamide dinucleotide (NADH) and flavin adenine dinucleotide (FAD), which can be used to monitor dramatic metabolic changes in cells and tissues. The goal of this study is to investigate changes in the endogenous fluorophore emission and to quantify metabolic changes in the redox state of various tissue transformation conditions with respect to control tissues in dimethyl benz[a] anthracene (DMBA)-induced hamster oral carcinogenesis for measuring emission spectrum at 320 nm excitation. In the present study, collagen, NADH and FAD emission of well-differentiated squamous cell carcinoma (WDSCC) showed decreased intensity at ~385 nm, ~450 nm and ~520 nm compared to hyperplasia, dysplasia and control tissues. Furthermore, a significant decrease in the optical redox ratio is observed in WDSCC tissues, which indicates an increased metabolic activity compared to the control tissues. Moreover, the principal component linear discriminant analysis (PC-LDA) algorithm together with the leave-one-out cross-validation (LOOCV) method yield an overall diagnostic sensitivity of 77.7% and a specificity of 88.8% in the classification of control, hyperplasia, dysplasia and WDSCC tissues, respectively. The results from this study demonstrated that fluorescence-based tissue analysis combined with PC-LDA has tremendous potential for the effective discrimination of control from neoplastic tissues; furthermore it also detects early neoplastic changes prior to definite morphologic alteration.

Coupled Environmental Processes in the Mojave Desert and Implications for ET Covers as Stable Landforms

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

D. Shafer; M. Y oung; S. Zitzer

2006-01-18

Monolayer evapotranspiration (ET) covers are the baseline method for closure of disposal sites for low-level radioactive waste (LLW), mixed LLW, and transuranic (TRU) waste at the Nevada Test Site (NTS). The regulatory timeline is typically 1,000 years for LLW and 10,000 years for TRU waste. Covers for such waste have different technical considerations than those with shorter timelines because they are subject to environmental change for longer periods of time, and because the environmental processes are often coupled. To evaluate these changes, four analog sites (approximately 30, 1,000 to 2,000, 7,000 to 12,500, and 125,000 years in age) on themore » NTS were analyzed to address the early post-institutional control period (the youngest site), the 1,000-year compliance period for disposal of LLW, and the 10,000-year period for TRU waste. Tests included soil texture, structure, and morphology; surface soil infiltration and hydraulic conductivity; vegetation and faunal surveys; and literature reviews. Separate measurements were made in plant undercanopy and intercanopy areas. The results showed a progressive increase in silt and clay content of surface soils with age. Changes in soil texture and structure led to a fivefold decline in saturated hydraulic conductivity in intercanopy areas, but no change in undercanopies, which were subject to bioturbation. These changes may have been responsible for the reduction in total plant cover, most dramatically in intercanopy areas, primarily because more precipitation either runs off the site or is held nearer to the surface where plant roots are less common. The results suggest that covers may evolve over longer timeframes to stable landforms that minimize the need for active maintenance.« less

Host responses of Japanese flounder Paralichthys olivaceus with lymphocystis cell formation.

PubMed

Iwakiri, Shogo; Song, Jun-Young; Nakayama, Kei; Oh, Myung-Joo; Ishida, Minoru; Kitamura, Shin-Ichi

2014-06-01

Lymphocystis disease virus (LCDV) is the causative agent of lymphocystis disease (LCD). In this study, we investigated the mechanisms of lymphocystis cell (LCC) formation from the viewpoint of gene expression changes in the infected fish. LCC occurrence and virus titers in the experimentally infected Japanese flounder, Paralichthys olivaceus were monitored by visual confirmation and real-time PCR, respectively. The gene expression changes in the fish fin were investigated by microarray experiments. LCCs firstly appeared in the fish at 21 days post infection (dpi). LCD incidence increased with time and reached 92.9% at 62 dpi. LCDV genome was firstly detected from dorsal fins at 14 dpi, and the relative amount of the genome gradually-increased until 56 dpi. Since the occurrence of LCC was approximately synchronized with increasing of the virus genome, virus replication might play important roles for LCC formation. The microarray detected a few gene expression changes until 28 dpi. However, the number of expression changed genes dramatically increased between 28 and 42 dpi in which LCCs formation was active. From the microarray data analyses, apoptosis and cell division related genes were down-regulated, whereas cell fusion and collagen related genes were up-regulated at 42 dpi. Together with the observation of morphological changes of LCCs in previous reports, it is suggested that the following steps are involved in LCC formation: the virus infected cells were (1) inhibited apoptotic death and (2) cell division before enlargement, (3) hypertrophied by cell fusion, and (4) surrounded by a hyaline capsule associated with the alteration of collagen fibers. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Challenge of High-resolution Mapping of Very Shallow Coastal Areas: Case Study of the Lagoon of Venice, Italy

NASA Astrophysics Data System (ADS)

Madricardo, F.; Foglini, F.; Kruss, A.; Bajo, M.; Campiani, E.; Ferrarin, C.; Fogarin, S.; Grande, V.; Janowski, L.; Keppel, E.; Leidi, E.; Lorenzetti, G.; Maicu, F.; Maselli, V.; Montereale Gavazzi, G.; Pellegrini, C.; Petrizzo, A.; Prampolini, M.; Remia, A.; Rizzetto, F.; Rovere, M.; Sarretta, A.; Sigovini, M.; Toso, C.; Zaggia, L.; Trincardi, F.

2017-12-01

Very shallow coastal environments are often highly urbanized with half of the world's population and 13 of the largest mega-cities located close to the coast. These environments undergo rapid morphological changes due to natural and anthropogenic pressure that will likely be enhanced in the near future by mean sea-level rise. Therefore, there is a strong need for high resolution seafloor mapping to monitor and protect shallow coastal areas. To date, only about 5% of their seafloor has been mapped: their shallowness has prevented so far the use of underwater acoustics to reveal their morphological features; their turbidity often hindered the efficient use of LIDAR technology, particularly in lagoons and estuaries. The recent technological development of multibeam echosounder systems, however, enables these instruments to achieve very high performances also in such shallow environments. In this work, we present the results of an extensive multibeam survey carried out in the Lagoon of Venice (Italy) in 2013. The Lagoon of Venice is the biggest lagoon in the Mediterranean Sea (surface area of about 550 km2, average depth of about 1 m) and it is a UNESCO World Cultural and Natural Heritage site together with the historical city of Venice which is currently endangered by relative sea-level rise. Major engineering works are ongoing at the lagoon inlets (MOSE project) to protect Venice from flood events. In the last century, the morphology and ecology of the lagoon changed dramatically: the extent of the salt marshes was reduced by 60% and some parts of the lagoon deepened by more than 1 m with a net sediment flux exiting from the inlets. To understand and monitor the future evolution of the Lagoon of Venice in view of the inlet modifications and mean sea-level rise, CNR-ISMAR within the project RITMARE (a National Research Programme funded by the Italian Ministry of University and Research) carried out an extensive survey, involving a team of more than 25 scientists, to collect high resolution (0.5 m) bathymetry of key study areas such as the tidal inlets and channels. Bathymetric and backscatter intensity data are now employed for geomorphologic studies, habitat mapping and modelling representing a paradigm of a broad multidisciplinary approach to monitor shallow coastal systems.

Anisotropic Morphological Changes in Goethite during Fe(2+)-Catalyzed Recrystallization.

PubMed

Joshi, Prachi; Gorski, Christopher A

2016-07-19

When goethite is exposed to aqueous Fe(2+), rapid and extensive Fe atom exchange can occur between solid-phase Fe(3+) and aqueous Fe(2+) in a process referred to as Fe(2+)-catalyzed recrystallization. This process can lead to the structural incorporation or release of trace elements, which has important implications for contaminant remediation and nutrient biogeochemical cycling. Prior work found that the process did not cause major changes to the goethite structure or morphology. Here, we further investigated if and how goethite morphology and aggregation behavior changed temporally during Fe(2+)-catalyzed recrystallization. On the basis of existing literature, we hypothesized that Fe(2+)-catalyzed recrystallization of goethite would not result in changes to individual particle morphology or interparticle interactions. To test this, we reacted nanoparticulate goethite with aqueous Fe(2+) at pH 7.5 over 30 days and used transmission electron microscopy (TEM), cryogenic TEM, and (55)Fe as an isotope tracer to observe changes in particle dimensions, aggregation, and isotopic composition over time. Over the course of 30 days, the goethite particles substantially recrystallized, and the particle dimensions changed anisotropically, resulting in a preferential increase in the mean particle width. The temporal changes in goethite morphology could not be completely explained by a single mineral-transformation mechanism but rather indicated that multiple transformation mechanisms occurred concurrently. Collectively, these results demonstrate that the morphology of goethite nanoparticles does change during recrystallization, which is an important step toward identifying the driving force(s) of recrystallization.

Effect of titanium ester on synthesizing NH2-MIL-125(Ti): Morphology changes from circular plate to octahedron and rhombic dodecahedron

NASA Astrophysics Data System (ADS)

Hu, Shen; Liu, Min; Guo, Xinwen; Kuang, Zhichong; Li, Keyan; Song, Chunshan; Zhang, Guoliang

2018-06-01

Titanium based MOF materials NH2-MIL-125 was synthesized through solvothermal method. By increasing the concentration of the reactants, the morphology of NH2-MIL-125 can be controlled from circular plate to special polyhedron. Meanwhile, the polyhedron can be modulated from octahedron to rhombic dodecahedron through changing the titanium ester of the reactants from tetraethyl titanate to tetrabutyl titanate. This is the first time to obtain NH2-MIL-125 with rhombic dodecahedron morphology. The test of acetic acid as additive on morphology changes shows that the adsorption of additives on special facets shows a more significant impact on the morphology formation. The morphology control of NH2-MIL-125 based on the modulation of the type of titanium ester, reactants concentration, and the added acetic acid concentration were detailed exhibited and explained.

Changing Families, Changing Workplaces

ERIC Educational Resources Information Center

Bianchi, Suzanne M.

2011-01-01

American families and workplaces have both changed dramatically over the past half-century. Paid work by women has increased sharply, as has family instability. Education-related inequality in work hours and income has grown. These changes, says Suzanne Bianchi, pose differing work-life issues for parents at different points along the income…

Ecuador's Higher Education System in Times of Change

ERIC Educational Resources Information Center

Van Hoof, Hubert B.; Estrella, Mateo; Eljuri, Marie-Isabel; León, Leonardo Torres

2013-01-01

Ecuador's higher education system is undergoing dramatic changes. The National Constitution of 2008 and the Higher Education Law of 2010 have changed the way Ecuador's universities are funded, administered, and accredited. The importance of research was elevated and drastic changes were made to the academic qualifications and employment conditions…

Social Change and Fathering: Change or Continuity in Vietnam?

ERIC Educational Resources Information Center

Jayakody, Rukmalie; Phuong, Pham Thi Thu

2013-01-01

Dramatic social changes have restructured virtually all aspects of Vietnam society. Although the economic consequences of these changes are well documented, little is known about how family roles and relationships have been affected. Because social and cultural contexts powerfully shape conceptions of parenting, the accelerated rate of social…

Changing times, changing stories: Generational differences in climate change perspectives from four remote indigenous communities in Subarctic Alaska

Treesearch

Nicole M. Herman-Mercer; Elli Matkin; Melinda J. Laituri; Ryan C. Toohey; Maggie Massey; Kelly Elder; Paul F. Schuster; Edda A. Mutter

2016-01-01

Indigenous Arctic and Subarctic communities currently are facing a myriad of social and environmental changes. In response to these changes, studies concerning indigenous knowledge (IK) and climate change vulnerability, resiliency, and adaptation have increased dramatically in recent years. Risks to lives and livelihoods are often the focus of adaptation...

Nuclear apoptotic volume decrease in individual cells: Confocal microscopy imaging and kinetic modeling.

PubMed

Khalo, Irina V; Konokhova, Anastasiya I; Orlova, Darya Y; Trusov, Konstantin V; Yurkin, Maxim A; Bartova, Eva; Kozubek, Stanislav; Maltsev, Valeri P; Chernyshev, Andrei V

2018-05-30

The dynamics of nuclear morphology changes during apoptosis remains poorly investigated and understood. Using 3D time-lapse confocal microscopy we performed a study of early-stage apoptotic nuclear morphological changes induced by etoposide in single living HepG2 cells. These observations provide a definitive evidence that nuclear apoptotic volume decrease (AVD) is occurring simultaneously with peripheral chromatin condensation (so called "apoptotic ring"). In order to describe quantitatively the dynamics of nuclear morphological changes in the early stage of apoptosis we suggest a general molecular kinetic model, which fits well the obtained experimental data in our study. Results of this work may clarify molecular mechanisms of nuclear morphology changes during apoptosis. Copyright © 2018 Elsevier Ltd. All rights reserved.

Morphological changes in ultrafast laser ablation plumes with varying spot size.

PubMed

Harilal, S S; Diwakar, P K; Polek, M P; Phillips, M C

2015-06-15

We investigated the role of spot size on plume morphology during ultrafast laser ablation of metal targets. Our results show that the spatial features of fs LA plumes are strongly dependent on the focal spot size. Two-dimensional self-emission images showed that the shape of the ultrafast laser ablation plumes changes from spherical to cylindrical with an increasing spot size from 100 to 600 μm. The changes in plume morphology and internal structures are related to ion emission dynamics from the plasma, where broader angular ion distribution and faster ions are noticed for the smallest spot size used. The present results clearly show that the morphological changes in the plume with spot size are independent of laser pulse width.

USE OF LIDAR TO MAP STREAM MORPHOLOGY AND MONITOR CHANGES DUE TO URBANIZATION OF A SMALL SUBURBAN WATERSHED

EPA Science Inventory

Urbanization has been associated with changes in stream flow regime, morphology, and water
quality of rural watersheds being developed. Most studies of the effect of urbanization on stream morphology have been done post hoc -after development has occurred -and involve the ext...

Dynamics of β-adrenergic/cAMP signaling and morphological changes in cultured astrocytes.

PubMed

Vardjan, Nina; Kreft, Marko; Zorec, Robert

2014-04-01

The morphology of astrocytes, likely regulated by cAMP, determines the structural association between astrocytes and the synapse, consequently modulating synaptic function. β-Adrenergic receptors (β-AR), which increase cytosolic cAMP concentration ([cAMP]i ), may affect cell morphology. However, the real-time dynamics of β-AR-mediated cAMP signaling in single live astrocytes and its effect on cell morphology have not been studied. We used the fluorescence resonance energy transfer (FRET)-based cAMP biosensor Epac1-camps to study time-dependent changes in [cAMP]i ; morphological changes in primary rat astrocytes were monitored by real-time confocal microscopy. Stimulation of β-AR by adrenaline, noradrenaline, and isoprenaline, a specific agonist of β-AR, rapidly increased [cAMP]i (∼15 s). The FRET signal response, mediated via β-AR, was faster than in the presence of forskolin (twofold) and dibutyryl-cAMP (>35-fold), which directly activate adenylyl cyclase and Epac1-camps, respectively, likely due to slow entry of these agents into the cytosol. Oscillations in [cAMP]i have not been recorded, indicating that cAMP-dependent processes operate in a slow time domain. Most Epac1-camps expressing astrocytes revealed a morphological change upon β-AR activation and attained a stellate morphology within 1 h. The morphological changes exhibited a bell-shaped dependency on [cAMP]i . The 5-10% decrease in cell cross-sectional area and the 30-50% increase in cell perimeter are likely due to withdrawal of the cytoplasm to the perinuclear region and the appearance of protrusions on the surface of astrocytes. Because astrocyte processes ensheath neurons, β-AR/cAMP-mediated morphological changes can modify the geometry of the extracellular space, affecting synaptic, neuronal, and astrocyte functions in health and disease. Copyright © 2014 Wiley Periodicals, Inc.

Mucoadhesive Microparticles for Gastroretentive Delivery: Preparation, Biodistribution and Targeting Evaluation

PubMed Central

Hou, Jing-Yi; Gao, Li-Na; Meng, Fan-Yun; Cui, Yuan-Lu

2014-01-01

The aim of this research was to prepare and characterize alginate-chitosan mucoadhesive microparticles containing puerarin. The microparticles were prepared by an emulsification-internal gelatin method using a combination of chitosan and Ca2+ as cationic components and alginate as anions. Surface morphology, particle size, drug loading, encapsulation efficiency and swelling ratio, in vitro drug released, in vitro evaluation of mucoadhesiveness and Fluorescence imaging of the gastrointestinal tract were determined. After optimization of the formulation, the encapsulation efficiency was dramatically increased from 70.3% to 99.2%, and a highly swelling ratio was achieved with a change in particle size from 50.3 ± 11.2 μm to 124.7 ± 25.6 μm. In ethanol induced gastric ulcers, administration of puerarin mucoadhesive microparticles at doses of 150 mg/kg, 300 mg/kg, 450 mg/kg and 600 mg/kg body weight prior to ethanol ingestion significantly protected the stomach ulceration. Consequently, significant changes were observed in inflammatory cytokines, such as prostaglandin E2 (PGE2), tumor necrosis factor (TNF-α), interleukin 6 (IL-6), and interleukin1β (IL-1β), in stomach tissues compared with the ethanol control group. In conclusion, core-shell type pH-sensitive mucoadhesive microparticles loaded with puerarin could enhance puerarin bioavailability and have the potential to alleviate ethanol-mediated gastric ulcers. PMID:25470180

Pathoproteomics of testicular tissue deficient in the GARP component VPS54: the wobbler mouse model of globozoospermia.

PubMed

Jockusch, Harald; Holland, Ashling; Staunton, Lisa; Schmitt-John, Thomas; Heimann, Peter; Dowling, Paul; Ohlendieck, Kay

2014-04-01

In human globozoospermia, round-headed spermatozoa lack an acrosome and therefore cannot properly interact with oocytes. In the wobbler (WR) mouse, an L967Q missense mutation in the vesicular protein-sorting factor VPS54 causes motor neuron degeneration and globozoospermia. Although electron microscopy of WR testis shows all major components of spermatogenesis, they appear in a deranged morphology that prevents the formation of the acrosome. In order to determine proteome-wide changes, affected testes were analysed by 2D-DIGE and MS. The concentration of 8 proteins was increased and that of 35 proteins decreased as compared to wild type. Mass spectrometric analysis identified proteins with an altered concentration to be associated with metabolite transport, fatty acid metabolism, cellular interactions, microtubule assembly and stress response (chaperones Hsp70-2 and Hsp90α). Minor changes were observed for proteins involved in cell redox homeostasis, cytoskeleton formation, PTMs, detoxification and metabolism. The most dramatically decreased protein in WR testis was identified as fatty acid binding protein FABP3, as confirmed by immunoblot analysis. We conclude that a missense mutation in VPS54, an essential component of the Golgi-associated retrograde protein complex, not only prevents the formation of an acrosome but also initiates a cascade of metabolic abnormalities and a stress reaction. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microsized Porous SiOx@C Composites Synthesized through Aluminothermic Reduction from Rice Husks and Used as Anode for Lithium-Ion Batteries.

PubMed

Cui, Jinlong; Cui, Yongfu; Li, Shaohui; Sun, Hongliang; Wen, Zhongsheng; Sun, Juncai

2016-11-09

Microsized porous SiO x @C composites used as anode for lithium-ion batteries (LIBs) are synthesized from rice husks (RHs) through low-temperature (700 °C) aluminothermic reduction. The resulting SiO x @C composite shows mesoporous irregular particle morphology with a high specific surface area of 597.06 m 2 /g under the optimized reduction time. This porous SiO x @C composite is constructed by SiO x nanoparticles uniformly dispersed in the C matrix. When tested as anode material for LIBs, it displays considerable specific capacity (1230 mAh/g at a current density of 0.1 A/g) and excellent cyclic stability with capacity fading of less than 0.5% after 200 cycles at 0.8 A/g. The dramatic volume change for the Si anode during lithium-ion (Li + ) insertion and extraction can be successfully buffered because of the formation of Li 2 O and Li 4 SiO 4 during initial lithiation process and carbon coating layer on the surface of SiO x . The porous structure could also mitigate the volume change and mechanical strains and shorten the Li + diffusion path length. These characteristics improve the cyclic stability of the electrode. This low-cost and environment-friendly SiO x @C composite anode material exhibits great potential as an alternative for traditional graphite anodes.

AFM combined to ATR-FTIR reveals Candida cell wall changes under caspofungin treatment.

PubMed

Quilès, Fabienne; Accoceberry, Isabelle; Couzigou, Célia; Francius, Grégory; Noël, Thierry; El-Kirat-Chatel, Sofiane

2017-09-21

Fungal pathogens from Candida genus are responsible for severe life-threatening infections and the antifungal arsenal is still limited. Caspofungin, an antifungal drug used for human therapy, acts as a blocking agent of the cell wall synthesis by inhibiting the β-1,3-glucan-synthase encoded by FKS genes. Despite its efficiency, the number of genetic mutants that are resistant to caspofungin is increasing. An important challenge to improve antifungal therapy is to understand cellular phenomenon that are associated with drug resistance. Here we used atomic force microscopy (AFM) combined to Fourier transform infrared spectroscopy in attenuated total reflection mode (ATR-FTIR) to decipher the effect of low and high drug concentration on the morphology, mechanics and cell wall composition of two Candida strains, one susceptible and one resistant to caspofungin. Our results confirm that caspofungin induces a dramatic cell wall remodelling via activation of stress responses, even at high drug concentration. Additionally, we highlighted unexpected changes related to drug resistance, suggesting that caspofungin resistance associated with FKS gene mutations comes from a combination of effects: (i) an overall remodelling of yeast cell wall composition; and (ii) cell wall stiffening through chitin synthesis. This work demonstrates that AFM combined to ATR-FTIR is a valuable approach to understand at the molecular scale the biological mechanisms associated with drug resistance.

Gene expression patterns during the larval development of European sea bass (dicentrarchus labrax) by microarray analysis.

PubMed

Darias, M J; Zambonino-Infante, J L; Hugot, K; Cahu, C L; Mazurais, D

2008-01-01

During the larval period, marine teleosts undergo very fast growth and dramatic changes in morphology, metabolism, and behavior to accomplish their metamorphosis into juvenile fish. Regulation of gene expression is widely thought to be a key mechanism underlying the management of the biological processes required for harmonious development over this phase of life. To provide an overall analysis of gene expression in the whole body during sea bass larval development, we monitored the expression of 6,626 distinct genes at 10 different points in time between 7 and 43 days post-hatching (dph) by using heterologous hybridization of a rainbow trout cDNA microarray. The differentially expressed genes (n = 485) could be grouped into two categories: genes that were generally up-expressed early, between 7 and 23 dph, and genes up-expressed between 25 and 43 dph. Interestingly, among the genes regulated during the larval period, those related to organogenesis, energy pathways, biosynthesis, and digestion were over-represented compared with total set of analyzed genes. We discuss the quantitative regulation of whole-body contents of these specific transcripts with regard to the ontogenesis and maturation of essential functions that take place over larval development. Our study is the first utilization of a transcriptomic approach in sea bass and reveals dynamic changes in gene expression patterns in relation to marine finfish larval development.

Changing America and the Changing Image of Scottsboro

ERIC Educational Resources Information Center

Murray, Hugh T., Jr.

1977-01-01

Discusses literary representations of Scottsboro. Notes that "the content of the extensive literature of Scottsboro changed dramatically, reflecting the radicalism of the 1930's, the cold-war liberalism of the 1950's, and the vacillations of the late 1960's early 70's. (Author/JM)

Flexible architecture of inducible morphological plasticity.

PubMed

Kishida, Osamu; Nishimura, Kinya

2006-05-01

1. Predator-induced morphological defences are produced in response to an emergent predator regime. In natural systems, prey organisms usually experience temporal shifting of the composition of the predator assemblage and of the intensity of predation risk from each predator species. Although, a repetitive morphological change in response to a sequential shift of the predator regime such as alteration of the predator species or diminution of the predation risk may be adaptive, such flexible inducible morphological defences are not ubiquitous. 2. We experimentally addressed whether a flexible inducible morphological defence is accomplished in response to serial changes in the predation regime, using a model prey species which adopt different defensive morphological phenotypes in response to different predator species. Rana pirica (Matsui) tadpoles increased body depth and tail depth against the predatory larval salamander Hynobius retardatus (Dunn); on the other hand, they only increased tail depth against the predatory larval dragonfly Aeshna nigroflava (Martin). 3. Rana pirica tadpoles with the predator-specific phenotypes were subjected to removal or exchange of the predator species. After removal of the predator species, tadpoles with each predator-specific phenotype changed their phenotype to the nondefensive basic one, suggesting that both predator-specific phenotypes are costly to maintain. After an exchange of the predator species, tadpoles with each predator-specific phenotype reciprocally, flexibly shifted their phenotype to the now more suitable predator-specific one only by modifying their body part. The partial modification can effectively reduce time and energy expenditures involved in repetitive morphological changes, and therefore suggest that the costs of the flexible morphological changes are reduced.

A young-onset frontal dementia with dramatic calcifications due to a novel CSF1R mutation.

PubMed

Gore, Ethan; Manley, Andrew; Dees, Daniel; Appleby, Brian S; Lerner, Alan J

2016-06-01

Neuroimaging and genomic analysis greatly aid in the identification of young-onset dementia antemortem. We present the case of a 33-year-old female with a 2-year rapid decline to dementia and immobility marked by personality change, executive deficits including compulsions, attention deficit, apraxia, Parkinsonism, and pyramidal signs. She had unique and dramatic calcifications and confluent white matter changes on imaging and was found to have a novel mutation in the colony stimulating factor 1 receptor gene causing adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP). Here, we review ALSP and briefly discuss differential diagnoses.

Charging effects in single InP/GaInP baby dots

NASA Astrophysics Data System (ADS)

Persson, Jonas

2001-03-01

It has recently been demonstrated that the matrix material plays a major role for the physical behavior of self-assembled InP/GaInP quantum dots. As the "intrinsically" n-type GaInP matrix fills the quantum dot with electrons the spectral behavior of the dot dramatically changes. For the larger, fully developed dots, the charging gives rise to several broad lines. With an external bias it is possible to reduce the electron population of the dot. For smaller dots, baby dots, we show the possibility of dramatically changing the appearance of the dot spectrum by a precise tuning of the size of the quantum dot. When the dot is small enough it is uncharged and the spectrum is very similar to other material systems, whereas a slightly larger dot is charged and the number of lines is dramatically increased. We present high spectral resolution photoluminescence measurements of individual InP/GaInP baby-dots and k\\cdotp calculations including direct and exchange interactions.

Morphological and Hydrodynamic Correlations with Increasing Outflow Facility by Rho-Kinase Inhibitor Y-27632

PubMed Central

Yang, Chen-Yuan Charlie

2014-01-01

Abstract Rho-kinase inhibitors affect actomyosin cytoskeletal networks and have been shown to significantly increase outflow facility and lower intraocular pressure in various animal models and human eyes. This article summarizes common morphological changes in the trabecular meshwork induced by Rho-kinase inhibitors and specifically compares the morphological and hydrodynamic correlations with increased outflow facility by Rho-kinase inhibitor, Y-27632, in bovine, monkey, and human eyes under similar experimental conditions. Interspecies comparison has shown that morphological changes in the juxtacanalicular connective tissue (JCT) of these 3 species were different. However, these different morphological changes in the JCT, no matter if it's separation between the JCT and inner wall in bovine eyes, or separation between the JCT cells or between the JCT cells and their matrix in monkey eyes, or even no separation between the inner wall and the JCT but a more subtle expansion of the JCT in human eyes, appear to correlate with the increased percent change of outflow facility. More importantly, these different morphological changes all resulted in an increase in effective filtration area, which was positively correlated with increased outflow facility in all 3 species. These results suggest a link among changes in outflow facility, tissue architecture, and aqueous outflow pattern. Y-27632 increases outflow facility by redistributing aqueous outflow through a looser and larger area in the JCT. PMID:24460021

Cellular and molecular responses of Neurospora crassa to non-thermal plasma at atmospheric pressure

NASA Astrophysics Data System (ADS)

Park, Gyungsoon; Ryu, Young H.; Hong, Young J.; Choi, Eun H.; Uhm, Han S.

2012-02-01

Filamentous fungi have been rarely explored in terms of plasma treatments. This letter presents the cellular and molecular responses of the filamentous fungus Neurospora crassa to an argon plasma jet at atmospheric pressure. The viability and cell morphology of N. crassa spores exposed to plasma were both significantly reduced depending on the exposure time when treated in water. The intracellular genomic DNA content was dramatically reduced in fungal tissues after a plasma treatment and the transcription factor tah-3 was found to be required for fungal tolerance to a harsh plasma environment.

Effect of Hydrogen and Carbamide Peroxide in Bleaching, Enamel Morphology, and Mineral Composition: In vitro Study.

PubMed

Llena, Carmen; Esteve, Irene; Forner, Leopoldo

2017-07-01

The aim of the study was to evaluate the bleaching effect, morphological changes, and variations in calcium (Ca) and phosphate (P) in the enamel with hydrogen peroxide (HP) and carbamide peroxide (CP) after the use of different application regimens. Four groups of five teeth were randomly assigned, according to the treatment protocol: HP 37.5% applied for 30 or 60 minutes (HP30, HP60), CP 16% applied for 14 or 28 hours (CP14, CP28). Changes in dental color were evaluated, according to the following formula: ΔE = [(L a -L b ) 2 +(a a -a b ) 2 + (b a -b b ) 2 ] 1/2 . Enamel morphology and Ca and P compositions were evaluated by confocal laser scanning microscope and environmental scanning electron microscopy. ΔE HP30 was significantly greater than CP14 (10.37 ± 2.65/8.56 ± 1.40), but not between HP60 and CP28. HP60 shows greater morphological changes than HP30. No morphological changes were observed in the groups treated with CP. The reduction in Ca and P was significantly greater in HP60 than in CP28 (p < 0.05). Both formulations improved tooth color; HP produced morphological changes and Ca and P a gradual decrease, while CP produced no morphological changes, and the decrease in mineral component was smaller. CP 16% applied during 2 weeks could be equally effective and safer for tooth whitening than to administer two treatment sessions with HP 37.5%.

Temporal downscaling of decadal sediment load estimates to a daily interval for use in hindcast simulations

USGS Publications Warehouse

Ganju, N.K.; Knowles, N.; Schoellhamer, D.H.

2008-01-01

In this study we used hydrologic proxies to develop a daily sediment load time-series, which agrees with decadal sediment load estimates, when integrated. Hindcast simulations of bathymetric change in estuaries require daily sediment loads from major tributary rivers, to capture the episodic delivery of sediment during multi-day freshwater flow pulses. Two independent decadal sediment load estimates are available for the Sacramento/San Joaquin River Delta, California prior to 1959, but they must be downscaled to a daily interval for use in hindcast models. Daily flow and sediment load data to the Delta are available after 1930 and 1959, respectively, but bathymetric change simulations for San Francisco Bay prior to this require a method to generate daily sediment load estimates into the Delta. We used two historical proxies, monthly rainfall and unimpaired flow magnitudes, to generate monthly unimpaired flows to the Sacramento/San Joaquin Delta for the 1851-1929 period. This step generated the shape of the monthly hydrograph. These historical monthly flows were compared to unimpaired monthly flows from the modern era (1967-1987), and a least-squares metric selected a modern water year analogue for each historical water year. The daily hydrograph for the modern analogue was then assigned to the historical year and scaled to match the flow volume estimated by dendrochronology methods, providing the correct total flow for the year. We applied a sediment rating curve to this time-series of daily flows, to generate daily sediment loads for 1851-1958. The rating curve was calibrated with the two independent decadal sediment load estimates, over two distinct periods. This novel technique retained the timing and magnitude of freshwater flows and sediment loads, without damping variability or net sediment loads to San Francisco Bay. The time-series represents the hydraulic mining period with sustained periods of increased sediment loads, and a dramatic decrease after 1910, corresponding to a reduction in available mining debris. The analogue selection procedure also permits exploration of the morphological hydrograph concept, where a limited set of hydrographs is used to simulate the same bathymetric change as the actual set of hydrographs. The final daily sediment load time-series and morphological hydrograph concept will be applied as landward boundary conditions for hindcasting simulations of bathymetric change in San Francisco Bay.

Changing Times: A Changing Public Sector May Require Changes to Public Management Education Programmes

ERIC Educational Resources Information Center

Oldfield, Chrissie

2017-01-01

It is becoming apparent that the environment in which Executive Masters in Public Administration programmes operate has changed dramatically in the wake of economic crisis and subsequent cuts in public spending. Changes in the funding of public sector organisations has been compounded by a broader "crisis" in the wider public sector…

Incorporating climate change and morphological uncertainty into coastal change hazard assessments

USGS Publications Warehouse

Baron, Heather M.; Ruggiero, Peter; Wood, Nathan J.; Harris, Erica L.; Allan, Jonathan; Komar, Paul D.; Corcoran, Patrick

2015-01-01

Documented and forecasted trends in rising sea levels and changes in storminess patterns have the potential to increase the frequency, magnitude, and spatial extent of coastal change hazards. To develop realistic adaptation strategies, coastal planners need information about coastal change hazards that recognizes the dynamic temporal and spatial scales of beach morphology, the climate controls on coastal change hazards, and the uncertainties surrounding the drivers and impacts of climate change. We present a probabilistic approach for quantifying and mapping coastal change hazards that incorporates the uncertainty associated with both climate change and morphological variability. To demonstrate the approach, coastal change hazard zones of arbitrary confidence levels are developed for the Tillamook County (State of Oregon, USA) coastline using a suite of simple models and a range of possible climate futures related to wave climate, sea-level rise projections, and the frequency of major El Niño events. Extreme total water levels are more influenced by wave height variability, whereas the magnitude of erosion is more influenced by sea-level rise scenarios. Morphological variability has a stronger influence on the width of coastal hazard zones than the uncertainty associated with the range of climate change scenarios.

Catchment-mediated atmospheric nitrogen deposition drives ecological change in two alpine lakes in SE Tibet.

PubMed

Hu, Zhujun; Anderson, Nicholas John; Yang, Xiangdong; McGowan, Suzanne

2014-05-01

The south-east margin of Tibet is highly sensitive to global environmental change pressures, in particular, high contemporary reactive nitrogen (Nr) deposition rates (ca. 40 kg ha(-1)  yr(-1) ), but the extent and timescale of recent ecological change is not well prescribed. Multiproxy analyses (diatoms, pigments and geochemistry) of (210) Pb-dated sediment cores from two alpine lakes in Sichuan were used to assess whether they have undergone ecological change comparable to those in Europe and North America over the last two centuries. The study lakes have contrasting catchment-to-lake ratios and vegetation cover: Shade Co has a relatively larger catchment and denser alpine shrub than Moon Lake. Both lakes exhibited unambiguous increasing production since the late 19th to early 20th. Principle component analysis was used to summarize the trends of diatom and pigment data after the little ice age (LIA). There was strong linear change in biological proxies at both lakes, which were not consistent with regional temperature, suggesting that climate is not the primary driver of ecological change. The multiproxy analysis indicated an indirect ecological response to Nr deposition at Shade Co mediated through catchment processes since ca. 1930, while ecological change at Moon Lake started earlier (ca. 1880) and was more directly related to Nr deposition (depleted δ(15) N). The only pronounced climate effect was evidenced by changes during the LIA when photoautotrophic groups shifted dramatically at Shade Co (a 4-fold increase in lutein concentration) and planktonic diatom abundance declined at both sites because of longer ice cover. The substantial increases in aquatic production over the last ca. 100 years required a substantial nutrient subsidy and the geochemical data point to a major role for Nr deposition although dust cannot be excluded. The study also highlights the importance of lake and catchment morphology for determining the response of alpine lakes to recent global environmental forcing. © 2013 John Wiley & Sons Ltd.

Silencing of ATP11B by RNAi-Induced Changes in Neural Stem Cell Morphology.

PubMed

Wang, Jiao; Wang, Qian; Zhou, Fangfang; Wang, Dong; Wen, Tieqiao

2017-01-01

RNA interference (RNAi) technology is one of the main research tools in many studies of neural stem cells. This study describes effects of ATP11B on the morphology change of neural stem cells by using RNAi. ATP11B belongs to P4-ATPases family, which is preferential translocate phosphatidylserine of cell membrane. Although it exists in neural stem cells, its physiological function is poorly understood. By using RNAi technology to downregulate expression of ATP11B, we found distinct morphological changes in neural stem cells. More important, psiRNA-ATP11B-transfected cells displayed short neurite outgrowth compared to the control cells. These data strongly suggest that ATP11B plays a key role in the morphological change of neural stem cells.

Morphological changes in ultrafast laser ablation plumes with varying spot size

DOE PAGES

Harilal, S. S.; Diwakar, P. K.; Polek, M. P.; ...

2015-06-04

We investigated the role of spot size on plume morphology during ultrafast laser ablation of metal targets. Our results show that the spatial features of fs LA plumes are strongly dependent on the focal spot size. Two-dimensional self-emission images showed that the shape of the ultrafast laser ablation plumes changes from spherical to cylindrical with an increasing spot size from 100 to 600 μm. The changes in plume morphology and internal structures are related to ion emission dynamics from the plasma, where broader angular ion distribution and faster ions are noticed for the smallest spot size used. The present resultsmore » clearly show that the morphological changes in the plume with spot size are independent of laser pulse width.« less

Double-Staining Method for Differentiation of Morphological Changes and Membrane Integrity of Campylobacter coli Cells

PubMed Central

Alonso, Jose L.; Mascellaro, Salvatore; Moreno, Yolanda; Ferrús, María A.; Hernández, Javier

2002-01-01

We developed a double-staining procedure involving NanoOrange dye (Molecular Probes, Eugene, Oreg.) and membrane integrity stains (LIVE/DEAD BacLight kit; Molecular Probes) to show the morphological and membrane integrity changes of Campylobacter coli cells during growth. The conversion from a spiral to a coccoid morphology via intermediary forms and the membrane integrity changes of the C. coli cells can be detected with the double-staining procedure. Our data indicate that young or actively growing cells are mainly spiral shaped (green-stained cells), but older cells undergo a degenerative change to coccoid forms (red-stained cells). Club-shaped transition cell forms were observed with NanoOrange stain. Chlorinated drinking water affected the viability but not the morphology of C. coli cells. PMID:12324366

GEOMORPHIC THRESHOLDS AND CHANNEL MORPHOLOGY IN LARGE RIVERS

EPA Science Inventory

Systematic changes in channel morphology occur as channel gradient, streamflow, and sediment character change and interact. Geomorphic thresholds of various kinds are useful metrics to define these changes along the river network, as they are based on in-channel processes that d...

University Outreach and Engagement: Responding to a Changing World

ERIC Educational Resources Information Center

Hrabowski, Freeman A., III; Weidemann, Craig D.

2004-01-01

Rapid and dramatic demographic and technological changes present the nation with enormous challenges for educating students, growing the economy, and responding to society's needs. America's colleges and universities have a central role to play in all of these critical areas--serving as agents of change as they themselves change institutionally in…

A gene network model accounting for development and evolution of mammalian teeth

PubMed Central

Salazar-Ciudad, Isaac; Jernvall, Jukka

2002-01-01

Generation of morphological diversity remains a challenge for evolutionary biologists because it is unclear how an ultimately finite number of genes involved in initial pattern formation integrates with morphogenesis. Ideally, models used to search for the simplest developmental principles on how genes produce form should account for both developmental process and evolutionary change. Here we present a model reproducing the morphology of mammalian teeth by integrating experimental data on gene interactions and growth into a morphodynamic mechanism in which developing morphology has a causal role in patterning. The model predicts the course of tooth-shape development in different mammalian species and also reproduces key transitions in evolution. Furthermore, we reproduce the known expression patterns of several genes involved in tooth development and their dynamics over developmental time. Large morphological effects frequently can be achieved by small changes, according to this model, and similar morphologies can be produced by different changes. This finding may be consistent with why predicting the morphological outcomes of molecular experiments is challenging. Nevertheless, models incorporating morphology and gene activity show promise for linking genotypes to phenotypes. PMID:12048258

Who gets custody now? Dramatic changes in children's living arrangements after divorce.

PubMed

Cancian, Maria; Meyer, Daniel R; Brown, Patricia R; Cook, Steven T

2014-08-01

This article reexamines the living arrangements of children following their parents' divorce, using Wisconsin Court Records, updating an analysis that showed relatively small but significant increases in shared custody in the late 1980s and early 1990s. These changes have accelerated markedly in the intervening years: between 1988 and 2008, the proportion of mothers granted sole physical custody fell substantially, the proportion of parents sharing custody increased dramatically, and father-sole custody remained relatively stable. We explore changes in the correlates of alternative custody outcomes, showing that some results from the earlier analysis still hold (for example, cases with higher total family income are more likely to have shared custody), but other differences have lessened (shared-custody cases have become less distinctive as they have become more common). Despite the considerable changes in marriage and divorce patterns over this period, we do not find strong evidence that the changes in custody are related to changes in the characteristics of families experiencing a divorce; rather, changes in custody may be the result of changes in social norms and the process by which custody is determined.

Effects of electromagnetic radiation on spatial memory and synapses in rat hippocampal CA1☆

PubMed Central

Li, Yuhong; Shi, Changhua; Lu, Guobing; Xu, Qian; Liu, Shaochen

2012-01-01

In this study, we investigated the effects of mobile phone radiation on spatial learning, reference memory, and morphology in related brain regions. After the near-field radiation (0.52–1.08 W/kg) was delivered to 8-week-old Wistar rats 2 hours per day for 1 month, behavioral changes were examined using the Morris water maze. Compared with the sham-irradiated rats, the irradiated rats exhibited impaired performance. Morphological changes were investigated by examining synaptic ultrastructural changes in the hippocampus. Using the physical dissector technique, the number of pyramidal neurons, the synaptic profiles, and the length of postsynaptic densities in the CA1 region were quantified stereologically. The morphological changes included mitochondrial degenerations, fewer synapses, and shorter postsynaptic densities in the radiated rats. These findings indicate that mobile phone radiation can significantly impair spatial learning and reference memory and induce morphological changes in the hippocampal CA1 region. PMID:25709623

Morphological change in machines accelerates the evolution of robust behavior

PubMed Central

Bongard, Josh

2011-01-01

Most animals exhibit significant neurological and morphological change throughout their lifetime. No robots to date, however, grow new morphological structure while behaving. This is due to technological limitations but also because it is unclear that morphological change provides a benefit to the acquisition of robust behavior in machines. Here I show that in evolving populations of simulated robots, if robots grow from anguilliform into legged robots during their lifetime in the early stages of evolution, and the anguilliform body plan is gradually lost during later stages of evolution, gaits are evolved for the final, legged form of the robot more rapidly—and the evolved gaits are more robust—compared to evolving populations of legged robots that do not transition through the anguilliform body plan. This suggests that morphological change, as well as the evolution of development, are two important processes that improve the automatic generation of robust behaviors for machines. It also provides an experimental platform for investigating the relationship between the evolution of development and robust behavior in biological organisms. PMID:21220304

An assessment of climate change in the Luquillo Mountains of Puerto Rico.

Treesearch

F. N. Scatena

1998-01-01

Change in the surface temperature of the coastal plain of 1 to 2C and/or a 11 to 33% change in annual rainfall could dramatically alter the distribution of forest vegetation within the Luquillo Experimental Forest(LEF) of northeastern Puerto Rico.

Institutional Influence on Behavioural Disorders in Early Adolescents

ERIC Educational Resources Information Center

Jayalekshmi, N. B.; Raja, B. William Dharma

2014-01-01

Early adolescence a period of transition between childhood and late adolescence, is where one experiences dramatic changes physically, and psychologically. These transitions cause cognitive, emotional, and social changes. The developmental changes that occur during this period cause varying degrees of disturbance in them. The period of transition…

The Changing Landscape of Disability in Childhood

ERIC Educational Resources Information Center

Halfon, Neal; Houtrow, Amy; Larson, Kandyce; Newacheck, Paul W.

2012-01-01

Americans' perceptions of childhood disability have changed dramatically over the past century, as have their ideas about health and illness, medical developments, threats to children's health and development, and expectations for child functioning. Neal Halfon, Amy Houtrow, Kandyce Larson, and Paul Newacheck examine how these changes have…

Slower Economic Growth Affects the 1995 Labor Market.

ERIC Educational Resources Information Center

Gardner, Jennifer M.; Hayghe, Howard V.

1996-01-01

Shows how job growth slowed dramatically in 1995, but the unemployment rate remained little changed. Discusses trends in nonfarm payroll employment by industry and changes in employment status of people in various demographic and occupational groups. (Author)

Global warming: China’s contribution to climate change

NASA Astrophysics Data System (ADS)

Spracklen, Dominick V.

2016-03-01

Carbon dioxide emissions from fossil-fuel use in China have grown dramatically in the past few decades, yet it emerges that the country's relative contribution to global climate change has remained surprisingly constant. See Letter p.357

Southeast Atmosphere Studies Workshop 2015

EPA Science Inventory

Concentrations of atmospheric trace species in the United States have changed dramatically over the past several decades in response to pollution control strategies, shifts in domestic energy policy, and economic development (and resulting emission changes) elsewhere in the world...

Morphological change to birds over 120 years is not explained by thermal adaptation to climate change.

PubMed

Salewski, Volker; Siebenrock, Karl-Heinz; Hochachka, Wesley M; Woog, Friederike; Fiedler, Wolfgang

2014-01-01

Changes in morphology have been postulated as one of the responses of animals to global warming, with increasing ambient temperatures leading to decreasing body size. However, the results of previous studies are inconsistent. Problems related to the analyses of trends in body size may be related to the short-term nature of data sets, to the selection of surrogates for body size, to the appropriate models for data analyses, and to the interpretation as morphology may change in response to ecological drivers other than climate and irrespective of size. Using generalized additive models, we analysed trends in three morphological traits of 4529 specimens of eleven bird species collected between 1889 and 2010 in southern Germany and adjacent areas. Changes and trends in morphology over time were not consistent when all species and traits were considered. Six of the eleven species displayed a significant association of tarsus length with time but the direction of the association varied. Wing length decreased in the majority of species but there were few significant trends in wing pointedness. Few of the traits were significantly associated with mean ambient temperatures. We argue that although there are significant changes in morphology over time there is no consistent trend for decreasing body size and therefore no support for the hypothesis of decreasing body size because of climate change. Non-consistent trends of change in surrogates for size within species indicate that fluctuations are influenced by factors other than temperature, and that not all surrogates may represent size appropriately. Future analyses should carefully select measures of body size and consider alternative hypotheses for change.

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.

Change of external sexual characteristics during consecutive moults in Crangon crangon L

NASA Astrophysics Data System (ADS)

Schatte, Jessica; Saborowski, Reinhard

2006-03-01

Adult males of the North Sea shrimp, Crangon crangon, were maintained for 8 months in the laboratory under natural temperature and light cycles. Successive moults were analysed for morphological changes. Out of the 70 shrimps, one male performed morphological sex reversal by reducing the male characteristics and developing female characteristics. The morphological changes including the loss of the appendix masculina appeared within a single moult cycle. This observation proves that C. crangon males may be capable of changing sex. The low number of sex reversals indicates that C. crangon is a facultative rather than an obligate protandric hermaphrodite.

Dramatic Enhancement in Photoresponse of β-In2S3 through Suppression of Dark Conductivity by Synthetic Control of Defect-Induced Carrier Compensation.

PubMed

Chaudhari, Nilima; Mandal, Lily; Game, Onkar; Warule, Sambhaji; Phase, Deodatta; Jadkar, Sandesh; Ogale, Satishchandra

2015-08-19

We report on the synthesis of dense and faceted indium sulfide (β-In2S3) nano-octahedron films on fluorine-doped tin oxide-coated glass by the hydrothermal method and their photoresponse properties in a flip chip device configuration. We have examined the temporal evolution of the phase constitution, morphology, and optoelectronic properties for films obtained after growth interruption at specific intervals. It is noted that, initially, an In(OH)3 film forms, which is gradually transformed to the β-In2S3 phase over time. In the case of the film wherein most, but not all, of In(OH)3 is consumed, an exceptionally large photoresponse (light to dark current ratio) of ∼10(4) and response time(s) (rise/fall) of ∼88/280 ms are realized. This superior performance is attributed to nearly complete carrier compensation achievable in the system under high pressure growth leading to dramatic reduction of dark conductivity. It is argued that the temporally growth-controlled equilibrium between quasi-In interstitials and cation vacancies dictates the optoelectronic properties.

Patterns of gene expression in atrophying skeletal muscles: response to food deprivation

NASA Technical Reports Server (NTRS)

Jagoe, R. Thomas; Lecker, Stewart H.; Gomes, Marcelo; Goldberg, Alfred L.

2002-01-01

During fasting and many systemic diseases, muscle undergoes rapid loss of protein and functional capacity. To define the transcriptional changes triggering muscle atrophy and energy conservation in fasting, we used cDNA microarrays to compare mRNAs from muscles of control and food-deprived mice. Expression of >94% of genes did not change, but interesting patterns emerged among genes that were differentially expressed: 1) mRNAs encoding polyubiquitin, ubiquitin extension proteins, and many (but not all) proteasome subunits increased, which presumably contributes to accelerated protein breakdown; 2) a dramatic increase in mRNA for the ubiquitin ligase, atrogin-1, but not most E3s; 3) a significant suppression of mRNA for myosin binding protein H (but not other myofibrillar proteins) and IGF binding protein 5, which may favor cell protein loss; 4) decreases in mRNAs for several glycolytic enzymes and phosphorylase kinase subunits, and dramatic increases in mRNAs for pyruvate dehydrogenase kinase 4 and glutamine synthase, which should promote glucose sparing and gluconeogenesis. During fasting, metallothionein mRNA increased dramatically, mRNAs for extracellular matrix components fell, and mRNAs that may favor cap-independent mRNA translation rose. Significant changes occurred in mRNAs for many growth-related proteins and transcriptional regulators. These transcriptional changes indicate a complex adaptive program that should favor protein degradation and suppress glucose oxidation in muscle. Similar analysis of muscles atrophying for other causes is allowing us to identify a set of atrophy-specific changes in gene expression.

Morphology of U 3O 8 materials following storage under controlled conditions of temperature and relative humidity

DOE PAGES

Tamasi, Alison L.; Cash, Leigh J.; Mullen, William Tyler; ...

2016-07-05

Changes in the visual characteristics of uranium oxide surfaces and morphology following storage under different conditions of temperature and relative humidity may provide insight into the history of an unknown sample. Sub-samples of three α-U 3O 8 materials—one that was phase-pure and two that were phase-impure—were stored under controlled conditions for two years. We used scanning electron microscopy to image the oxides before and after storage, and a morphology lexicon was used to characterize the images. Finally, temporal changes in morphology were observed in some sub-samples, and changes were greatest following exposure to high relative humidity.

Nutrient limitation and morphological plasticity of the carnivorous pitcher plant Sarracenia purpurea in contrasting wetland environments.

PubMed

Bott, Terry; Meyer, Gretchen A; Young, Erica B

2008-01-01

* Plasticity of leaf nutrient content and morphology, and macronutrient limitation were examined in the northern pitcher plant, Sarracenia purpurea subsp. purpurea, in relation to soil nutrient availability in an open, neutral pH fen and a shady, acidic ombrotrophic bog, over 2 yr following reciprocal transplantation of S. purpurea between the wetlands. * In both wetlands, plants were limited by nitrogen (N) but not phosphorus (P) (N content < 2% DW(-1), N : P < 14) but photosynthetic quantum yields were high (F(V)/F(M) > 0.79). Despite carnivory, leaf N content correlated with dissolved N availability to plant roots (leaf N vs , r(2) = 0.344, P < 0.0001); carnivorous N acquisition did not apparently overcome N limitation. * Following transplantation, N content and leaf morphological traits changed in new leaves to become more similar to plants in the new environment, reflecting wetland nutrient availability. Changes in leaf morphology were faster when plants were transplanted from fen to bog than from bog to fen, possibly reflecting a more stressful environment in the bog. * Morphological plasticity observed in response to changes in nutrient supply to the roots in natural habitats complements previous observations of morphological changes with experimental nutrient addition to pitchers.

In-Situ Atomic Force Microscope Imaging of Calcite Etch Pit Morphology Changes in Undersaturated and 1-Hydroxyethylidene-1,1-diphosphonic Acid Poisoned Solutions

PubMed Central

Britt, David W.

2012-01-01

Morphology changes in etch pits formed on the (1014) cleavage plane of calcite were induced by varying the ratio of [Ca2+] to [CO32−] in the bulk solution as well as through the addition of the crystal poison 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP). Three distinct morphologies were noted: symmetric rhombic, asymmetric rhombic, and triangular with a rough curved hypotenuse. The latter represents a transient morphology which is only observed during the actual dissolution process, while the former morphologies persist after dissolution is halted. PMID:25125794

Rectal cancer surgery: a brief history.

PubMed

Galler, Avi S; Petrelli, Nicholas J; Shakamuri, Shanthi P

2011-12-01

In the last 250 years, the treatment of rectal cancer has changed dramatically. Once considered an incurable disease, combined modality therapy has improved mortality from 100% to less than 4% for locally advanced rectal cancer. This dramatic reduction paralleled surgical techniques based on a growing understanding of anatomy and disease pathology. In order to understand modern treatment, it is necessary to recognize the achievements of preceding surgeons. Copyright © 2010 Elsevier Ltd. All rights reserved.

Name Changes in Medically Important Fungi and Their Implications for Clinical Practice

PubMed Central

de Hoog, G. Sybren; Chaturvedi, Vishnu; Denning, David W.; Dyer, Paul S.; Frisvad, Jens Christian; Geiser, David; Gräser, Yvonne; Guarro, Josep; Haase, Gerhard; Kwon-Chung, Kyung-Joo; Meyer, Wieland; Pitt, John I.; Samson, Robert A.; Tintelnot, Kathrin; Vitale, Roxana G.; Walsh, Thomas J.

2014-01-01

Recent changes in the Fungal Code of Nomenclature and developments in molecular phylogeny are about to lead to dramatic changes in the naming of medically important molds and yeasts. In this article, we present a widely supported and simple proposal to prevent unnecessary nomenclatural instability. PMID:25297326

Society Membership Profile: Employment Mobility and Career Change. AIP Report.

ERIC Educational Resources Information Center

Porter, Beverly Fearn; Kellman, Dawn

Information on the influence of employment mobility and career change on the flexibility of the physics labor force is provided, noting the past several decades have brought a dramatic roller coaster of changes to the physics community. Five sections are as follows: membership composition (demographics, professional self-identification, and…

Multiple-scale proximal sensor and remote imagery technology for sustaining agricultural productivity during climate change

USDA-ARS?s Scientific Manuscript database

Changes in climatic patterns have had dramatic influence on agricultural areas worldwide, particularly in irrigated arid-zone agricultural areas subjected to recurring drought, such as California’s San Joaquin Valley. Climate change has impacted water availability, which subsequently has impacted so...

Dangerous Gulf? The Relationship between America and its All-Volunteer Military

DTIC Science & Technology

2013-03-01

altering transformations like finding or converting to a new religion, or even turning Vegan . The pronounced changes brought on by a dramatic change...846961/celebrating- motherhood-how-becoming-a-mom-changes-you (accessed January 14, 2008); Colleen Patrick- Goudreau, “The Joyful Vegan : Stories of

School Business Administration: A Planning Approach. Third Edition.

ERIC Educational Resources Information Center

Candoli, I. Carl; And Others

The school business administration function in the operation of American schools has undergone dramatic changes during the past several years. Changing demographics, high technology, the movement to professionalize school administration, and changes by the legislative and judicial systems have all had significant impact on the character of school…

Changing Roles of Special Education Administrators: Impact on Multicultural Learners

ERIC Educational Resources Information Center

Bakken, Jeffrey P.; O'Brian, Mary; Shelden, Debra L.

2006-01-01

It is imperative for special education administrators, and all administrators, to adapt to the changing demographic and educational environments. The field of special education has changed dramatically in the last three decades, and administrators can and should be leaders of the continued evolution of special education. One useful organizing…

A study on electromigration-inducing intergranular fracture of fine silver alloy wires

NASA Astrophysics Data System (ADS)

Hsueh, Hao-Wen; Hung, Fei-Yi; Lui, Truan-Sheng

2017-01-01

In this study, Pd-coated Cu, Ag (purity = 4 N), and Ag alloy (Ag-8Au-3Pd) wires were employed to measure the tensile properties during current stressing using the so-called dynamic current tensile (DCT) test. Both the tensile strength and elongation of the wires decreased dramatically in the DCT test, particularly of the Ag-based wires, and the fracture morphology of the Cu-based and Ag-based wires was ductile fracture and intergranular fracture, respectively. Compared to the Cu-based wires, electromigration occurred more easily in the Ag-based wires, and it always generated voids and cracks at the grain boundaries; therefore, the fracture morphology of the Ag-based wires was intergranular fracture owing to the weakened grain boundary. Further, the results indicated that the Ag-based wires could not carry a higher current density than the Cu-based wires, primarily because their extremely low strength and elongation in current stressing might cause serious reliability problems.

Effect of the size-selective silver clusters on lithium peroxide morphology in lithium–oxygen batteries

DOE PAGES

Lu, Jun; Cheng, Lei; Lau, Kah Chun; ...

2014-09-12

Lithium–oxygen batteries have the potential needed for long-range electric vehicles, but the charge and discharge chemistries are complex and not well understood. The active sites on cathode surfaces and their role in electrochemical reactions in aprotic lithium–oxygen cells are difficult to ascertain because the exact nature of the sites is unknown. In this paper, we report the deposition of subnanometre silver clusters of exact size and number of atoms on passivated carbon to study the discharge process in lithium–oxygen cells. The results reveal dramatically different morphologies of the electrochemically grown lithium peroxide dependent on the size of the clusters. Thismore » dependence is found to be due to the influence of the cluster size on the formation mechanism, which also affects the charge process. Finally, the results of this study suggest that precise control of subnanometre surface structure on cathodes can be used as a means to improve the performance of lithium–oxygen cells.« less

Tracing the trilobite tree from the root to the tips: a model marriage of fossils and phylogeny.

PubMed

Lieberman, Bruce S; Karim, Talia S

2010-01-01

Trilobites are a highly diverse group of extinct arthropods that persisted for nearly 300 million years. During that time, there was a profusion of morphological form, and they occupied a plethora of marine habitats. Their diversity, relative abundance, and complex morphology make them excellent candidates for phylogenetic analysis, and partly as a consequence they have been the subject of many cladistic studies. Although phylogenetic knowledge is certainly incomplete, our understanding of evolutionary patterns within the group has dramatically increased over the last 30 years. Moreover, trilobites have formed an important component of various studies of macroevolutionary processes. Here, we summarize the phylogenetic breadth of knowledge on the Trilobita, and present various hypotheses about phylogenetic patterns within the group, from the highest to the lowest taxonomic levels. Key topics we consider include the question of trilobite monophyly, the phylogenetic position of trilobites vis à vis extant arthropod groups, and inter- and intra-ordinal relationships. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Muscle Functional Morphology in Paleobiology: The Past, Present, and Future of "Paleomyology".

PubMed

Perry, Jonathan M G; Prufrock, Kristen A

2018-03-01

Our knowledge of muscle anatomy and physiology in vertebrates has increased dramatically over the last two-hundred years. Today, much is understood about how muscles contract and about the functional meaning of muscular variation at multiple scales. Progress in muscle anatomy has profited from the availability of broad comparative samples, advances in microscopy have permitted comparisons at increasingly finer scales, and progress in muscle physiology has profited from many carefully designed and executed experiments. Several avenues of future work are promising. In particular, muscle ontogeny (growth and development) is poorly understood for many vertebrate groups. We consider which types of advances in muscle functional morphology are of use to paleobiologists. These are only a modest subset for muscle anatomy and a very small subset for muscle physiology. The relationship between muscle and bone - spatially and mechanically-is critical to any future advances in "paleomyology". Anat Rec, 301:538-555, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Counter-rotational cell flows drive morphological and cell fate asymmetries in mammalian hair follicles.

PubMed

Cetera, Maureen; Leybova, Liliya; Joyce, Bradley; Devenport, Danelle

2018-05-01

Organ morphogenesis is a complex process coordinated by cell specification, epithelial-mesenchymal interactions and tissue polarity. A striking example is the pattern of regularly spaced, globally aligned mammalian hair follicles, which emerges through epidermal-dermal signaling and planar polarized morphogenesis. Here, using live-imaging, we discover that developing hair follicles polarize through dramatic cell rearrangements organized in a counter-rotational pattern of cell flows. Upon hair placode induction, Shh signaling specifies a radial pattern of progenitor fates that, together with planar cell polarity, induce counter-rotational rearrangements through myosin and ROCK-dependent polarized neighbour exchanges. Importantly, these cell rearrangements also establish cell fate asymmetry by repositioning radial progenitors along the anterior-posterior axis. These movements concurrently displace associated mesenchymal cells, which then signal asymmetrically to maintain polarized cell fates. Our results demonstrate how spatial patterning and tissue polarity generate an unexpected collective cell behaviour that in turn, establishes both morphological and cell fate asymmetry.

Ancient DNA and morphometric analysis reveal extinction and replacement of New Zealand's unique black swans.

PubMed

Rawlence, Nicolas J; Kardamaki, Afroditi; Easton, Luke J; Tennyson, Alan J D; Scofield, R Paul; Waters, Jonathan M

2017-07-26

Prehistoric human impacts on megafaunal populations have dramatically reshaped ecosystems worldwide. However, the effects of human exploitation on smaller species, such as anatids (ducks, geese, and swans) are less clear. In this study we apply ancient DNA and osteological approaches to reassess the history of Australasia's iconic black swans ( Cygnus atratus ) including the palaeo-behaviour of prehistoric populations. Our study shows that at the time of human colonization, New Zealand housed a genetically, morphologically, and potentially ecologically distinct swan lineage ( C. sumnerensis , Poūwa), divergent from modern (Australian) C. atratus Morphological analyses indicate C. sumnerensis exhibited classic signs of the 'island rule' effect, being larger, and likely flight-reduced compared to C. atratus Our research reveals sudden extinction and replacement events within this anatid species complex, coinciding with recent human colonization of New Zealand. This research highlights the role of anthropogenic processes in rapidly reshaping island ecosystems and raises new questions for avian conservation, ecosystem re-wilding, and de-extinction. © 2017 The Author(s).

Enhancing fullerene-based solar cell lifetimes by addition of a fullerene dumbbell.

PubMed

Schroeder, Bob C; Li, Zhe; Brady, Michael A; Faria, Gregório Couto; Ashraf, Raja Shahid; Takacs, Christopher J; Cowart, John S; Duong, Duc T; Chiu, Kar Ho; Tan, Ching-Hong; Cabral, João T; Salleo, Alberto; Chabinyc, Michael L; Durrant, James R; McCulloch, Iain

2014-11-17

Cost-effective, solution-processable organic photovoltaics (OPV) present an interesting alternative to inorganic silicon-based solar cells. However, one of the major remaining challenges of OPV devices is their lack of long-term operational stability, especially at elevated temperatures. The synthesis of a fullerene dumbbell and its use as an additive in the active layer of a PCDTBT:PCBM-based OPV device is reported. The addition of only 20 % of this novel fullerene not only leads to improved device efficiencies, but more importantly also to a dramatic increase in morphological stability under simulated operating conditions. Dynamic secondary ion mass spectrometry (DSIMS) and TEM are used, amongst other techniques, to elucidate the origins of the improved morphological stability. © 2014 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Deep-water longline fishing has reduced impact on Vulnerable Marine Ecosystems

PubMed Central

Pham, Christopher K.; Diogo, Hugo; Menezes, Gui; Porteiro, Filipe; Braga-Henriques, Andreia; Vandeperre, Frederic; Morato, Telmo

2014-01-01

Bottom trawl fishing threatens deep-sea ecosystems, modifying the seafloor morphology and its physical properties, with dramatic consequences on benthic communities. Therefore, the future of deep-sea fishing relies on alternative techniques that maintain the health of deep-sea ecosystems and tolerate appropriate human uses of the marine environment. In this study, we demonstrate that deep-sea bottom longline fishing has little impact on vulnerable marine ecosystems, reducing bycatch of cold-water corals and limiting additional damage to benthic communities. We found that slow-growing vulnerable species are still common in areas subject to more than 20 years of longlining activity and estimate that one deep-sea bottom trawl will have a similar impact to 296–1,719 longlines, depending on the morphological complexity of the impacted species. Given the pronounced differences in the magnitude of disturbances coupled with its selectivity and low fuel consumption, we suggest that regulated deep-sea longlining can be an alternative to deep-sea bottom trawling. PMID:24776718

Anisotropic MoS2 Nanosheets Grown on Self-Organized Nanopatterned Substrates.

PubMed

Martella, Christian; Mennucci, Carlo; Cinquanta, Eugenio; Lamperti, Alessio; Cappelluti, Emmanuele; Buatier de Mongeot, Francesco; Molle, Alessandro

2017-05-01

Manipulating the anisotropy in 2D nanosheets is a promising way to tune or trigger functional properties at the nanoscale. Here, a novel approach is presented to introduce a one-directional anisotropy in MoS 2 nanosheets via chemical vapor deposition (CVD) onto rippled patterns prepared on ion-sputtered SiO 2 /Si substrates. The optoelectronic properties of MoS 2 are dramatically affected by the rippled MoS 2 morphology both at the macro- and the nanoscale. In particular, strongly anisotropic phonon modes are observed depending on the polarization orientation with respect to the ripple axis. Moreover, the rippled morphology induces localization of strain and charge doping at the nanoscale, thus causing substantial redshifts of the phonon mode frequencies and a topography-dependent modulation of the MoS 2 workfunction, respectively. This study paves the way to a controllable tuning of the anisotropy via substrate pattern engineering in CVD-grown 2D nanosheets. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Teaching Tip: Are You Changing the Rules? Again?

ERIC Educational Resources Information Center

Rice, Theodore

2012-01-01

Students often complain that the rules of mathematics are being changed. A short conversation between a professor and a class of college algebra students dramatizes this in the realm of complex numbers and the legal realm of speed limits.

Southeast Atmosphere Studies: learning from model-observation syntheses

EPA Science Inventory

Concentrations of atmospheric trace species in the United States have changed dramatically over the past several decades in response to pollution control strategies, shifts in domestic energy policy and economics, and economic development (and resulting emission changes) elsewher...

Cellular and molecular maturation in fetal and adult ovine calcaneal tendons

PubMed Central

Russo, Valentina; Mauro, Annunziata; Martelli, Alessandra; Di Giacinto, Oriana; Di Marcantonio, Lisa; Nardinocchi, Delia; Berardinelli, Paolo; Barboni, Barbara

2015-01-01

Processes of development during fetal life profoundly transform tendons from a plastic tissue into a highly differentiated structure, characterised by a very low ability to regenerate after injury in adulthood. Sheep tendon is frequently used as a translational model to investigate cell-based regenerative approaches. However, in contrast to other species, analytical and comparative baseline studies on the normal developmental maturation of sheep tendons from fetal through to adult life are not currently available. Thus, a detailed morphological and biochemical study was designed to characterise tissue maturation during mid- (2 months of pregnancy: 14 cm of length) and late fetal (4 months: 40 cm of length) life, through to adulthood. The results confirm that ovine tendon morphology undergoes profound transformations during this period. Endotenon was more developed in fetal tendons than in adult tissues, and its cell phenotype changed through tendon maturation. Indeed, groups of large rounded cells laying on smaller and more compacted ones expressing osteocalcin, vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) were identified exclusively in fetal mid-stage tissues, and not in late fetal or adult tendons. VEGF, NGF as well as blood vessels and nerve fibers showed decreased expression during tendon development. Moreover, the endotenon of mid- and late fetuses contained identifiable cells that expressed several pluripotent stem cell markers [Telomerase Reverse Transcriptase (TERT), SRY Determining Region Y Box-2 (SOX2), Nanog Homeobox (NANOG) and Octamer Binding Transcription Factor-4A (OCT-4A)]. These cells were not identifiable in adult specimens. Ovine tendon development was also accompanied by morphological modifications to cell nuclei, and a progressive decrease in cellularity, proliferation index and expression of connexins 43 and 32. Tendon maturation was similarly characterised by modulation of several other gene expression profiles, including Collagen type I, Collagen type III, Scleraxis B, Tenomodulin, Trombospondin 4 and Osteocalcin. These gene profiles underwent a dramatic reduction in adult tissues. Transforming growth factor-1 expression (involved in collagen synthesis) underwent a similar decrease. In conclusion, these morphological studies carried out on sheep tendons at different stages of development and aging offer normal structural and molecular baseline data to allow accurate evaluation of data from subsequent interventional studies investigating tendon healing and regeneration in ovine experimental models. PMID:25546075

The Remarkable Change in Euro-American Cranial Shape and Size.

PubMed

Jantz, Richard L; Jantz, Lee Meadows

2016-01-01

Secular changes in stature, weight, or other components of the body that can be obtained from historical records have been extensively studied. Cranial change has been central to anthropology for more than a century, but the focus has normally been on change measured in centuries or millennia. Cranial change measured in decades, normally considered to result from plastic response to the environment, has been less studied. This article reports on change in cranial vault dimensions in white Americans. Variables were glabello-occipital length (GOL), basion-bregma height (BBH), basion-nasion length (BNL), maximum cranial breadth (XCB), and biauricular breadth (AUB). Cranial size was calculated as the geometric mean of these variables, and shape dimensions were calculated as described by Darroch and Mosimann ( 1985 ). Cranial module and cranial capacity were also calculated. Samples consisted of 1,112 males and 668 females complete for those variables. Samples were organized into 10-year birth cohorts, with birth years ranging from 1820 to 1990. One-way ANOVA was used to test for variation among cohorts. The pattern of secular change was examined graphically and was compared with quality-of-life and environmental indicators, including stature, infant mortality, calories per person, and relative number of immigrants. All variables showed significant secular change, but BBH, XCB, and BNL responded most strongly. Over the past 170 years, crania became relatively higher, narrower, and larger with longer cranial bases. Both sexes changed, but female change was less pronounced than male change. The cranial variables tracked secular changes in stature, most prominently BNL. The highest correlation between a cranial variable and quality-of-life indicator was BBH and infant mortality. We are not able to identify specific causes of secular changes in cranial morphology. However, given that modern Americans have introduced themselves into a novel environment never before experienced by human populations, we consider it unlikely that it is pure plasticity. In addition to possible plastic responses, it is likely that selection, acting through the dramatic changes in infant mortality, is also involved.

Adsorbate-driven morphological changes on Cu(111) nano-pits

DOE PAGES

Mudiyanselage, K.; Xu, F.; Hoffmann, F. M.; ...

2014-12-09

Adsorbate-driven morphological changes of pitted-Cu(111) surfaces have been investigated following the adsorption and desorption of CO and H. The morphology of the pitted-Cu(111) surfaces, prepared by Ar + sputtering, exposed a few atomic layers deep nested hexagonal pits of diameters from 8 to 38 nm with steep step bundles. The roughness of pitted-Cu(111) surfaces can be healed by heating to 450-500 K in vacuum. Adsorption of CO on the pitted-Cu(111) surface leads to two infrared peaks at 2089-2090 and 2101-2105 cm -1 for CO adsorbed on under-coordinated sites in addition to the peak at 2071 cm -1 for CO adsorbedmore » on atop sites of the close-packed Cu(111) surface. CO adsorbed on under-coordinated sites is thermally more stable than that of atop Cu(111) sites. Annealing of the CO-covered surface from 100 to 300 K leads to minor changes of the surface morphology. In contrast, annealing of a H covered surface to 300 K creates a smooth Cu(111) surface as deduced from infrared data of adsorbed CO and scanning tunnelling microscopy (STM) imaging. The observation of significant adsorbate-driven morphological changes with H is attributed to its stronger modification of the Cu(111) surface by the formation of a sub-surface hydride with a hexagonal structure, which relaxes into the healed Cu(111) surface upon hydrogen desorption. These morphological changes occur ~150 K below the temperature required for healing of the pitted-Cu(111) surface by annealing in vacuum. In contrast, the adsorption of CO, which only interacts with the top-most Cu layer and desorbs by 160 K, does not significantly change the morphology of the pitted-Cu(111) surface.« less

A mimic study on effects of fluoride on tooth enamel structures

NASA Astrophysics Data System (ADS)

Ma, Guobin; Wang, Mu; Liu, Xiang Yang

2010-03-01

Tooth enamel is the hardest tissue in human body, and this superior mechanical property is contributed by its unique microstructures, i.e., oriented growth of rod-like apatite crystals into basic structural units called the prisms Fluoride (F^-) has been recognized to have significant effects on the physical and chemical properties of tooth enamel. However, the role of F^- on microstructures of apatite crystals is not well understood yet. Here we report a detailed investigation on the topic. Mimic in vitro growth of tooth enamel structures is performed at the biophysical conditions in simulated body fluids, using belt-like hydroxyapatite crystals as substrates It shows that F^- on the order of 0.1 mM will dramatically change the morphology of the grown crystals from irregular slabs to nano-needles, and the needles are aligned along the substrate with an average misorientation of ˜12 . Branched growth of bundles of nano-needles occurs with further increase of F^-, and finally, growth of highly porous structures as well as microspheres takes place when the F^- concentration exceeds 5 mM. In comparison with real tooth enamel structures, the relationship between enamel microstructures and tooth caries as well as fluorosis is discussed.

Peroxisome proliferator-activated receptors: bridging metabolic syndrome with molecular nutrition.

PubMed

Guri, Amir J; Hontecillas, Raquel; Bassaganya-Riera, Josep

2006-12-01

Over recent years, obesity rates and the onset of obesity-induced chronic diseases have risen dramatically. The more we learn about the physiological and morphological changes that occur during obesity, the more it is becoming clear that obesity-related disorders can be traced back to adipocyte hypertrophy and inflammation at white adipose tissue (WAT). To combat this problem, the body has developed a regulatory system specifically designed at mediating the systemic response to obesity, utilizing free fatty acids (FFAs) and their metabolites as nutrient messengers to signal adaptations from peripheral tissues. These messages are predominantly interceded through the peroxisome proliferator-activated receptors (PPARs), a family of ligand-induced transcription factors that serve as a net of lipid sensors throughout the body. Understanding how and why nutrients, nutrient derivatives and metabolites exert their physiological effects are the key goals in the study of molecular nutrition. By learning about the mechanisms and tissue-specific effects of endogenous PPAR ligands and expanding our knowledge of the body's integrated homeostatic system, we will significantly increase our odds of designing safe and effective preventive and therapeutic interventions that keep us one step ahead of obesity-related diseases.

Analysis of passivated A-286 stainless steel surfaces for mass spectrometer inlet systems by Auger electron and X-ray photoelectron spectroscopy and scanning electron microscopy

DOE PAGES

Ajo, Henry; Blankenship, Donnie; Clark, Elliot

2014-07-25

In this study, various commercially available surface treatments are being explored for use on stainless steel components in mass spectrometer inlet systems. Type A-286 stainless steel coupons, approximately 12.5 mm in diameter and 3 mm thick, were passivated with one of five different surface treatments; an untreated coupon served as a control. The surface and near-surface microstructure and chemistry of the coupons were investigated using sputter depth profiling using Auger electron spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). All the surface treatments studied appeared to change the surface morphology dramatically, as evidenced by lack of tool marks onmore » the treated samples in SEM images. In terms of the passivation treatment, Vendors A-D appeared to have oxide layers that were very similar in thickness to each other (0.7–0.9 nm thick), as well as to the untreated samples (the untreated sample oxide layers appeared to be somewhat larger). Vendor E’s silicon coating appears to be on the order of 200 nm thick.« less

Reverse engineering the euglenoid movement: from unicellular swimmers to bio-inspired robots

NASA Astrophysics Data System (ADS)

Desimone, Antonio; Noselli, Giovanni; Arroyo, Marino

Euglenids are unicelluar organisms living in freshwater, which are capable of moving either by beating a flagellum, or by executing dramatic shape changes. These are accomplished thanks to a complex structure made of interlocking pellicle strips, microtubules, and motor proteins. Relative sliding of the pellicle strips, suitably orchestrated, can cause the propagation of a bulge along the body, hence generating a propulsive force. We study the mechanisms by which the sliding of pellicle strips leads to shape control and locomotion, by means of both theory (through the mechanics of active surfaces and its coupling to computational fluid dynamics for the surrounding fluid) and experimental observations. Moreover, we implement them into a new concept of a surface with programmable shape, obtained by asssembling 3d-printed strips in a construct mimicking the biological template. We explore the range of possible geometries achievable by actuating these surfaces, to assess their potential in soft robotics applications. The subtle balance between constraints and flexibility leads to a wide variety of shapes that can be obtained with relatively simple controls, similar to the notion of morphological computation in biological systems. ERC Advanced Grant 340685 (MicroMotility).

The development of malaria parasites in the mosquito midgut

PubMed Central

Bennink, Sandra; Kiesow, Meike J.

2016-01-01

Summary The mosquito midgut stages of malaria parasites are crucial for establishing an infection in the insect vector and to thus ensure further spread of the pathogen. Parasite development in the midgut starts with the activation of the intraerythrocytic gametocytes immediately after take‐up and ends with traversal of the midgut epithelium by the invasive ookinetes less than 24 h later. During this time period, the plasmodia undergo two processes of stage conversion, from gametocytes to gametes and from zygotes to ookinetes, both accompanied by dramatic morphological changes. Further, gamete formation requires parasite egress from the enveloping erythrocytes, rendering them vulnerable to the aggressive factors of the insect gut, like components of the human blood meal. The mosquito midgut stages of malaria parasites are unprecedented objects to study a variety of cell biological aspects, including signal perception, cell conversion, parasite/host co‐adaptation and immune evasion. This review highlights recent insights into the molecules involved in gametocyte activation and gamete formation as well as in zygote‐to‐ookinete conversion and ookinete midgut exit; it further discusses factors that can harm the extracellular midgut stages as well as the measures of the parasites to protect themselves from any damage. PMID:27111866

Diversity of endophytic fungi of Myricaria laxiflora grown under pre- and post-flooding conditions.

PubMed

Tian, W; Bi, Y H; Zeng, W; Jiang, W; Xue, Y H; Wang, G X; Liu, S P

2015-09-09

Myricaria laxiflora is distributed along the riverbanks of the Yangtze River valley. The Three Gorges Dam has dramatically changed the habitat of M. laxiflora, which has evolved to develop increased resistance to flooding stress. In order to elucidate the relationship between plant endophytic fungi and flooding stress, we isolated and taxonomically characterized the endophytic fungi of M. laxiflora. One hundred and sixty-three fungi were isolated from healthy stems, leaves and roots of M. laxiflora grown under pre- and post-flooding conditions. Culture and isolation were carried out under aerobic and anaerobic conditions. Based on internal transcribed spacer sequence analysis and morphological characteristics, the isolates exhibited abundant biodiversity; they were classified into 5 subphyla, 7 classes, 12 orders, 17 families, and 26 genera. Dominant endophytes varied between pre- and post-flooding plants, among different plant tissues, and between aerobic and anaerobic culture conditions. Aspergillus and Alternaria accounted for more than 55% of all isolates. Although the number of isolates from post-flooding plants was greater, endophytes from pre-flooding plants were more diverse and abundant. Endophytes were distributed preferentially in particular tissues; this affinity was constrained by both the host habitat and the oxygen availability of the host.

Fibrinogen Motif Discriminates Platelet and Cell Capture in Peptide-Modified Gold Micropore Arrays.

PubMed

Adamson, Kellie; Spain, Elaine; Prendergast, Una; Moran, Niamh; Forster, Robert J; Keyes, Tia E

2018-01-16

Human blood platelets and SK-N-AS neuroblastoma cancer-cell capture at spontaneously adsorbed monolayers of fibrinogen-binding motifs, GRGDS (generic integrin adhesion), HHLGGAKQAGDV (exclusive to platelet integrin α IIb β 3 ), or octanethiol (adhesion inhibitor) at planar gold and ordered 1.6 μm diameter spherical cap gold cavity arrays were compared. In all cases, arginine/glycine/aspartic acid (RGD) promoted capture, whereas alkanethiol monolayers inhibited adhesion. Conversely only platelets adhered to alanine/glycine/aspartic acid (AGD)-modified surfaces, indicating that the AGD motif is recognized preferentially by the platelet-specific integrin, α IIb β 3 . Microstructuring of the surface effectively eliminated nonspecific platelet/cell adsorption and dramatically enhanced capture compared to RGD/AGD-modified planar surfaces. In all cases, adhesion was reversible. Platelets and cells underwent morphological change on capture, the extent of which depended on the topography of the underlying substrate. This work demonstrates that both the nature of the modified interface and its underlying topography influence the capture of cancer cells and platelets. These insights may be useful in developing cell-based cancer diagnostics as well as in identifying strategies for the disruption of platelet cloaks around circulating tumor cells.

Effects of cholesterol on plasma membrane lipid order in MCF-7 cells by two-photon microscopy

NASA Astrophysics Data System (ADS)

Zeng, Yixiu; Chen, Jianling; Yang, Hongqin; Wang, Yuhua; Li, Hui; Xie, Shusen

2014-09-01

Lipid rafts are cholesterol- and glycosphingolipids- enriched microdomains on plasma membrane surface of mammal cells, involved in a variety of cellular processes. Depleting cholesterol from the plasma membrane by drugs influences the trafficking of lipid raft markers. Optical imaging techniques are powerful tools to study lipid rafts in live cells due to its noninvasive feature. In this study, breast cancer cells MCF-7 were treated with different concentrations of MβCD to deplete cholesterol and an environmentally sensitive fluorescence probe, Laurdan was loaded to image lipid order by two-photon microscopy. The generalized polarization (GP) values were calculated to distinguish the lipid order and disorder phase. GP images and GP distributions of native and cholesterol-depleted MCF-7 cells were obtained. Our results suggest that even at low concentration (0.5 mM) of MβCD, the morphology of the MCF-7 cells changes. Small high GP areas (lipid order phase) decrease more rapidly than low GP areas (lipid disorder phase), indicating that lipid raft structure was altered more severely than nonraft domains. The data demonstrates that cholesterol dramatically affect raft coverage and plasma membrane fluidity in living cells.

Pressure-induced dramatic changes in organic–inorganic halide perovskites

PubMed Central

Yang, Wenge

2017-01-01

Organic–inorganic halide perovskites have emerged as a promising family of functional materials for advanced photovoltaic and optoelectronic applications with high performances and low costs. Various chemical methods and processing approaches have been employed to modify the compositions, structures, morphologies, and electronic properties of hybrid perovskites. However, challenges still remain in terms of their stability, the use of environmentally unfriendly chemicals, and the lack of an insightful understanding into structure–property relationships. Alternatively, pressure, a fundamental thermodynamic parameter that can significantly alter the atomic and electronic structures of functional materials, has been widely utilized to further our understanding of structure–property relationships, and also to enable emergent or enhanced properties of given materials. In this perspective, we describe the recent progress of high-pressure research on hybrid perovskites, particularly regarding pressure-induced novel phenomena and pressure-enhanced properties. We discuss the effect of pressure on structures and properties, their relationships and the underlying mechanisms. Finally, we give an outlook on future research avenues in which high pressure and related alternative methods such as chemical tailoring and interfacial engineering may lead to novel hybrid perovskites uniquely suited for high-performance energy applications. PMID:29147500

Serratia marcescens is injurious to intestinal epithelial cells

PubMed Central

Ochieng, John B; Boisen, Nadia; Lindsay, Brianna; Santiago, Araceli; Ouma, Collins; Ombok, Maurice; Fields, Barry; Stine, O Colin; Nataro, James P

2014-01-01

Diarrhea causes substantial morbidity and mortality in children in low-income countries. Although numerous pathogens cause diarrhea, the etiology of many episodes remains unknown. Serratia marcescens is incriminated in hospital-associated infections, and HIV/AIDS associated diarrhea. We have recently found that Serratia spp. may be found more commonly in the stools of patients with diarrhea than in asymptomatic control children. We therefore investigated the possible enteric pathogenicity of S. marcescens in vitro employing a polarized human colonic epithelial cell (T84) monolayer. Infected monolayers were assayed for bacterial invasion, transepithelial electrical resistance (TEER), cytotoxicity, interleukin-8 (IL-8) release and morphological changes by scanning electron microscopy. We observed significantly greater epithelial cell invasion by S. marcescens compared to Escherichia coli strain HS (p = 0.0038 respectively). Cell invasion was accompanied by reduction in TEER and secretion of IL-8. Lactate dehydrogenase (LDH) extracellular concentration rapidly increased within a few hours of exposure of the monolayer to S. marcescens. Scanning electron microscopy of S. marcescens-infected monolayers demonstrated destruction of microvilli and vacuolization. Our results suggest that S. marcescens interacts with intestinal epithelial cells in culture and induces dramatic alterations similar to those produced by known enteric pathogens. PMID:25426769

Serratia marcescens is injurious to intestinal epithelial cells.

PubMed

Ochieng, John B; Boisen, Nadia; Lindsay, Brianna; Santiago, Araceli; Ouma, Collins; Ombok, Maurice; Fields, Barry; Stine, O Colin; Nataro, James P

2014-01-01

Diarrhea causes substantial morbidity and mortality in children in low-income countries. Although numerous pathogens cause diarrhea, the etiology of many episodes remains unknown. Serratia marcescens is incriminated in hospital-associated infections, and HIV/AIDS associated diarrhea. We have recently found that Serratia spp. may be found more commonly in the stools of patients with diarrhea than in asymptomatic control children. We therefore investigated the possible enteric pathogenicity of S. marcescens in vitro employing a polarized human colonic epithelial cell (T84) monolayer. Infected monolayers were assayed for bacterial invasion, transepithelial electrical resistance (TEER), cytotoxicity, interleukin-8 (IL-8) release and morphological changes by scanning electron microscopy. We observed significantly greater epithelial cell invasion by S. marcescens compared to Escherichia coli strain HS (p = 0.0038 respectively). Cell invasion was accompanied by reduction in TEER and secretion of IL-8. Lactate dehydrogenase (LDH) extracellular concentration rapidly increased within a few hours of exposure of the monolayer to S. marcescens. Scanning electron microscopy of S. marcescens-infected monolayers demonstrated destruction of microvilli and vacuolization. Our results suggest that S. marcescens interacts with intestinal epithelial cells in culture and induces dramatic alterations similar to those produced by known enteric pathogens.

Polymorphism in Bacterial Flagella Suspensions

NASA Astrophysics Data System (ADS)

Schwenger, Walter J.

Bacterial flagella are a type of biological polymer studied for its role in bacterial motility and the polymorphic transitions undertaken to facilitate the run and tumble behavior. The naturally rigid, helical shape of flagella gives rise to novel colloidal dynamics and material properties. This thesis studies methods in which the shape of bacterial flagella can be controlled using in vitro methods and the changes the shape of the flagella have on both single particle dynamics and bulk material properties. We observe individual flagellum in both the dilute and semidilute regimes to observe the effects of solvent condition on the shape of the filament as well as the effect the filament morphology has on reptation through a network of flagella. In addition, we present rheological measurements showing how the shape of filaments effects the bulk material properties of flagellar suspensions. We find that the individual particle dynamics in suspensions of flagella can vary with geometry from needing to reptate linearly via rotation for helical filaments to the prevention of long range diffusion for block copolymer filaments. Similarly, for bulk material properties of flagella suspensions, helical geometries show a dramatic enhancement in elasticity over straight filaments while block copolymers form an elastic gel without the aid of crosslinking agents.

Morphological variation in salamanders and their potential response to climate change.

PubMed

Ficetola, Gentile Francesco; Colleoni, Emiliano; Renaud, Julien; Scali, Stefano; Padoa-Schioppa, Emilio; Thuiller, Wilfried

2016-06-01

Despite the recognition that some species might quickly adapt to new conditions under climate change, demonstrating and predicting such a fundamental response is challenging. Morphological variations in response to climate may be caused by evolutionary changes or phenotypic plasticity, or both, but teasing apart these processes is difficult. Here, we built on the number of thoracic vertebrae (NTV) in ectothermic vertebrates, a known genetically based feature, to establish a link with body size and evaluate how climate change might affect the future morphological response of this group of species. First, we show that in old-world salamanders, NTV variation is strongly related to changes in body size. Secondly, using 22 salamander species as a case study, we found support for relationships between the spatial variation in selected bioclimatic variables and NTV for most of species. For 44% of species, precipitation and aridity were the predominant drivers of geographical variation of the NTV. Temperature features were dominant for 31% of species, while for 19% temperature and precipitation played a comparable role. This two-step analysis demonstrates that ectothermic vertebrates may evolve in response to climate change by modifying the number of thoracic vertebrae. These findings allow to develop scenarios for potential morphological evolution under future climate change and to identify areas and species in which the most marked evolutionary responses are expected. Resistance to climate change estimated from species distribution models was positively related to present-day species morphological response, suggesting that the ability of morphological evolution may play a role for species' persistence under climate change. The possibility that present-day capacity for local adaptation might help the resistance response to climate change can be integrated into analyses of the impact of global changes and should also be considered when planning management actions favouring species persistence. © 2016 John Wiley & Sons Ltd.

Hydro-geomorphology of the middle Elwha River, Washington, following dam removal

NASA Astrophysics Data System (ADS)

Morgan, J. A.; Nelson, P. A.; Brogan, D. J.

2017-12-01

Dam removal is an increasingly common river restoration practice, which can produce dramatic increases in sediment supply to downstream reaches. There remains, however, considerable uncertainty in how mesoscale morphological units (e.g., riffles and pools) respond to the flow and sediment supply changes associated with dam removal. The recent removal of Glines Canyon Dam on the Elwha River in Washington State provides a natural setting to explore how increased sediment supply due to dam removal may affect downstream reaches. Here, we present observations and surveys documenting how a 1 km reach, located approximately 5 km downstream of the former dam site, has evolved following dam removal. Annual topographic/bathymetric surveys were conducted in 2014-2016 using RTK-GNSS methods, and these surveys were coupled with airborne lidar to create continuous surface maps of the valley bottom. Differencing the elevation models reveals channel widening and migration due to lateral bank retreat and bar aggradation. Analysis of aerial imagery dating back to 1939 suggests that rates of both widening and meander migration have increased following dam removal. We also used results from depth-averaged hydrodynamic modeling with a fuzzy c-means clustering approach to delineate riffle and pool units; this analysis suggests that both riffles and pools stayed relatively consistent from 2014-2015, while both areas decreased from 2015 to 2016. Without any considerable changes to the hydrologic regime these higher rates of change are implied to be the result of the increased sediment supply. Our results, which indicate an increased dynamism due directly to the amplified sediment supply, have the potential to further inform river managers and restoration specialists who oversee projects related to changing sediment regimes.

Changing Families in a Changing Military System.

ERIC Educational Resources Information Center

Hunter, Edna J., Ed.

Recently, the military system has begun to feel the impact of the military family. Whenever sudden dramatic changes or transitions occur, crises may result either for the individual or for the institution. At present both the military system and the military family are in a period of rapid transition. Perhaps one of the most important changes that…

Advanced manufacturing: Technology and international competitiveness

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

Tesar, A.

1995-02-01

Dramatic changes in the competitiveness of German and Japanese manufacturing have been most evident since 1988. All three countries are now facing similar challenges, and these challenges are clearly observed in human capital issues. Our comparison of human capital issues in German, Japanese, and US manufacturing leads us to the following key judgments: Manufacturing workforces are undergoing significant changes due to advanced manufacturing technologies. As companies are forced to develop and apply these technologies, the constituency of the manufacturing workforce (especially educational requirements, contingent labor, job content, and continuing knowledge development) is being dramatically and irreversibly altered. The new workforcemore » requirements which result due to advanced manufacturing require a higher level of worker sophistication and responsibility.« less

Adaptation of a Simple Microfluidic Platform for High-Dimensional Quantitative Morphological Analysis of Human Mesenchymal Stromal Cells on Polystyrene-Based Substrates.

PubMed

Lam, Johnny; Marklein, Ross A; Jimenez-Torres, Jose A; Beebe, David J; Bauer, Steven R; Sung, Kyung E

2017-12-01

Multipotent stromal cells (MSCs, often called mesenchymal stem cells) have garnered significant attention within the field of regenerative medicine because of their purported ability to differentiate down musculoskeletal lineages. Given the inherent heterogeneity of MSC populations, recent studies have suggested that cell morphology may be indicative of MSC differentiation potential. Toward improving current methods and developing simple yet effective approaches for the morphological evaluation of MSCs, we combined passive pumping microfluidic technology with high-dimensional morphological characterization to produce robust tools for standardized high-throughput analysis. Using ultraviolet (UV) light as a modality for reproducible polystyrene substrate modification, we show that MSCs seeded on microfluidic straight channel devices incorporating UV-exposed substrates exhibited morphological changes that responded accordingly to the degree of substrate modification. Substrate modification also effected greater morphological changes in MSCs seeded at a lower rather than higher density within microfluidic channels. Despite largely comparable trends in morphology, MSCs seeded in microscale as opposed to traditional macroscale platforms displayed much higher sensitivity to changes in substrate properties. In summary, we adapted and qualified microfluidic cell culture platforms comprising simple straight channel arrays as a viable and robust tool for high-throughput quantitative morphological analysis to study cell-material interactions.

Spatiotemporal Receptive Field Properties of a Looming-Sensitive Neuron in Solitarious and Gregarious Phases of the Desert Locust

PubMed Central

Harston, George W. J.; Kilburn-Toppin, Fleur; Matheson, Thomas; Burrows, Malcolm; Gabbiani, Fabrizio; Krapp, Holger G.

2010-01-01

Desert locusts (Schistocerca gregaria) can transform reversibly between the swarming gregarious phase and a solitarious phase, which avoids other locusts. This transformation entails dramatic changes in morphology, physiology, and behavior. We have used the lobula giant movement detector (LGMD) and its postsynaptic target, the descending contralateral movement detector (DCMD), which are visual interneurons that detect looming objects, to analyze how differences in the visual ecology of the two phases are served by altered neuronal function. Solitarious locusts had larger eyes and a greater degree of binocular overlap than those of gregarious locusts. The receptive field to looming stimuli had a large central region of nearly equal response spanning 120° × 60° in both phases. The DCMDs of gregarious locusts responded more strongly than solitarious locusts and had a small caudolateral focus of even further sensitivity. More peripherally, the response was reduced in both phases, particularly ventrally, with gregarious locusts showing greater proportional decrease. Gregarious locusts showed less habituation to repeated looming stimuli along the eye equator than did solitarious locusts. By contrast, in other parts of the receptive field the degree of habituation was similar in both phases. The receptive field organization to looming stimuli contrasts strongly with the receptive field organization of the same neurons to nonlooming local-motion stimuli, which show much more pronounced regional variation. The DCMDs of both gregarious and solitarious locusts are able to detect approaching objects from across a wide expanse of visual space, but phase-specific changes in the spatiotemporal receptive field are linked to lifestyle changes. PMID:19955292

Effects of genistein, a soybean-derived isoflavone, on proliferation and differentiation of B16-BL6 mouse melanoma cells.

PubMed

Yan, C H; Chen, X G; Li, Y; Han, R

1999-01-01

Genistein, a soybean-derived isoflavone, may contribute to the lower cancer incidence in South Asian countries. In this study, the effects and molecular mechanisms of genistein on growth and differentiation of B16-BL6 mouse melanoma cells were investigated. Genistein suppressed the growth of these melanoma cells. The IC50 value is 15.5 microM. On the other hand, genistein induced the changes of cell shape and cytoskeletal network. The cytoskeletal filaments were induced to form a bundle along the direction of elongation of the cells. Moreover, tyrosine phosphorylation levels of cytoskeleton-associated proteins decreased after the cells were exposed to 20 or 30 microM of genistein for 3 days. All these morphological and molecular changes were accompanied by appearance of the differentiated phenotypes. Genistein induced the increase of cellular melanin content, enhancement of tyrosinase activity, and decrease of colonization potentials in soft agar in a time-dependent and dose-dependent manner. The effective concentration was no more than 10 microM after 3 days' exposure. The tumorigenic potentials of B16-BL6 cells in C57BL/6 mouse also decreased after exposure to 20 or 30 microM of genistein for 3 days. When expressions of tumor-related genes were investigated in the differentiation-induced cells, the content of P53 dramatically increased while that of c-Myc protein decreased. Therefore, due to its ability to induce cellular and molecular changes, genistein suppressed the growth and induced differentiated phenotypes in B16-BL6 melanoma cells.

Conservation of Endo16 expression in sea urchins despite evolutionary divergence in both cis and trans-acting components of transcriptional regulation

NASA Technical Reports Server (NTRS)

Romano, Laura A.; Wray, Gregory A.

2003-01-01

Evolutionary changes in transcriptional regulation undoubtedly play an important role in creating morphological diversity. However, there is little information about the evolutionary dynamics of cis-regulatory sequences. This study examines the functional consequence of evolutionary changes in the Endo16 promoter of sea urchins. The Endo16 gene encodes a large extracellular protein that is expressed in the endoderm and may play a role in cell adhesion. Its promoter has been characterized in exceptional detail in the purple sea urchin, Strongylocentrotus purpuratus. We have characterized the structure and function of the Endo16 promoter from a second sea urchin species, Lytechinus variegatus. The Endo16 promoter sequences have evolved in a strongly mosaic manner since these species diverged approximately 35 million years ago: the most proximal region (module A) is conserved, but the remaining modules (B-G) are unalignable. Despite extensive divergence in promoter sequences, the pattern of Endo16 transcription is largely conserved during embryonic and larval development. Transient expression assays demonstrate that 2.2 kb of upstream sequence in either species is sufficient to drive GFP reporter expression that correctly mimics this pattern of Endo16 transcription. Reciprocal cross-species transient expression assays imply that changes have also evolved in the set of transcription factors that interact with the Endo16 promoter. Taken together, these results suggest that stabilizing selection on the transcriptional output may have operated to maintain a similar pattern of Endo16 expression in S. purpuratus and L. variegatus, despite dramatic divergence in promoter sequence and mechanisms of transcriptional regulation.

Evolution Of The Cloud Field And Wind Structure Of Ntb Disturbance

NASA Astrophysics Data System (ADS)

Barrado-Izagirre, Naiara; Pérez-Hoyos, S.; García-Melendo, E.; Sánchez-Lavega, A.

2009-09-01

The banded visual aspect of cloud patterns in Jupiter hides markedly turbulent areas visible in high resolution images. The North Temperate Belt (NTB) at 21° N planetocentric latitude where the most intense Jovian jet resides (with speeds of 160 - 180 m/s) is a region of particular interest because it is known to suffer almost every 15 years an eruption or disturbance which dramatically changes its appearance. This phenomenon is known as NTB Disturbance (NTBD). The last one of such disturbances happened in 2007 and was captured by the Hubble Space Telescope and with lower resolution by the "International Outer Planet Watch” (IOPW) network [Sánchez-Lavega et al., 2008. Depth of a strong Jovian jet from a planetary-scale disturbance driven by storms, Nature 451.]. In this work we make use of these observations to characterize the morphology of the disturbed cloud field in the wake of the plumes which originated the perturbation. This is done mostly in terms of the brightness spectral distribution in order to characterize the typical spatial frequency of the perturbation and its wavy and turbulent nature. In addition we make a comparison of the jet profile in the NTB just after the disturbance ended (June 2007) with one obtained year later (July 2008). It shows that a change occurred in its anticyclonic side producing a reinforced westward jet at 17°N with a speed change of 30 m/s. Acknowledgments: This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07

Changes in gene expression, protein content and morphology of chondrocytes cultured on a 3D Random Positioning Machine and 2D rotating clinostat

NASA Astrophysics Data System (ADS)

Aleshcheva, Ganna; Hauslage, Jens; Hemmersbach, Ruth; Infanger, Manfred; Bauer, Johann; Grimm, Daniela; Sahana, Jayashree

Chondrocytes are the only cell type found in human cartilage consisting of proteoglycans and type II collagen. Several studies on chondrocytes cultured either in Space or on a ground-based facility for simulation of microgravity revealed that these cells are very resistant to adverse effects and stress induced by altered gravity. Tissue engineering of chondrocytes is a new strategy for cartilage regeneration. Using a three-dimensional Random Positioning Machine and a 2D rotating clinostat, devices designed to simulate microgravity on Earth, we investigated the early effects of microgravity exposure on human chondrocytes of six different donors after 30 min, 2 h, 4 h, 16 h, and 24 h and compared the results with the corresponding static controls cultured under normal gravity conditions. As little as 30 min of exposure resulted in increased expression of several genes responsible for cell motility, structure and integrity (beta-actin); control of cell growth, cell proliferation, cell differentiation and apoptosis; and cytoskeletal components such as microtubules (beta-tubulin) and intermediate filaments (vimentin). After 4 hours disruptions in the vimentin network were detected. These changes were less dramatic after 16 hours, when human chondrocytes appeared to reorganize their cytoskeleton. However, the gene expression and protein content of TGF-β1 was enhanced for 24 h. Based on the results achieved, we suggest that chondrocytes exposed to simulated microgravity seem to change their extracellular matrix production behavior while they rearrange their cytoskeletal proteins prior to forming three-dimensional aggregates.

Leaf morphology shift linked to climate change.

PubMed

Guerin, Greg R; Wen, Haixia; Lowe, Andrew J

2012-10-23

Climate change is driving adaptive shifts within species, but research on plants has been focused on phenology. Leaf morphology has demonstrated links with climate and varies within species along climate gradients. We predicted that, given within-species variation along a climate gradient, a morphological shift should have occurred over time due to climate change. We tested this prediction, taking advantage of latitudinal and altitudinal variations within the Adelaide Geosyncline region, South Australia, historical herbarium specimens (n = 255) and field sampling (n = 274). Leaf width in the study taxon, Dodonaea viscosa subsp. angustissima, was negatively correlated with latitude regionally, and leaf area was negatively correlated with altitude locally. Analysis of herbarium specimens revealed a 2 mm decrease in leaf width (total range 1-9 mm) over 127 years across the region. The results are consistent with a morphological response to contemporary climate change. We conclude that leaf width is linked to maximum temperature regionally (latitude gradient) and leaf area to minimum temperature locally (altitude gradient). These data indicate a morphological shift consistent with a direct response to climate change and could inform provenance selection for restoration with further investigation of the genetic basis and adaptive significance of observed variation.

Automated Morphological Analysis of Microglia After Stroke.

PubMed

Heindl, Steffanie; Gesierich, Benno; Benakis, Corinne; Llovera, Gemma; Duering, Marco; Liesz, Arthur

2018-01-01

Microglia are the resident immune cells of the brain and react quickly to changes in their environment with transcriptional regulation and morphological changes. Brain tissue injury such as ischemic stroke induces a local inflammatory response encompassing microglial activation. The change in activation status of a microglia is reflected in its gradual morphological transformation from a highly ramified into a less ramified or amoeboid cell shape. For this reason, the morphological changes of microglia are widely utilized to quantify microglial activation and studying their involvement in virtually all brain diseases. However, the currently available methods, which are mainly based on manual rating of immunofluorescent microscopic images, are often inaccurate, rater biased, and highly time consuming. To address these issues, we created a fully automated image analysis tool, which enables the analysis of microglia morphology from a confocal Z-stack and providing up to 59 morphological features. We developed the algorithm on an exploratory dataset of microglial cells from a stroke mouse model and validated the findings on an independent data set. In both datasets, we could demonstrate the ability of the algorithm to sensitively discriminate between the microglia morphology in the peri-infarct and the contralateral, unaffected cortex. Dimensionality reduction by principal component analysis allowed to generate a highly sensitive compound score for microglial shape analysis. Finally, we tested for concordance of results between the novel automated analysis tool and the conventional manual analysis and found a high degree of correlation. In conclusion, our novel method for the fully automatized analysis of microglia morphology shows excellent accuracy and time efficacy compared to traditional analysis methods. This tool, which we make openly available, could find application to study microglia morphology using fluorescence imaging in a wide range of brain disease models.

Phosphoproteome analysis reveals a critical role for hedgehog signalling in osteoblast morphological transitions.

PubMed

Marumoto, Ariane; Milani, Renato; da Silva, Rodrigo A; da Costa Fernandes, Célio Junior; Granjeiro, José Mauro; Ferreira, Carmen V; Peppelenbosch, Maikel P; Zambuzzi, Willian F

2017-10-01

The reciprocal and adaptive interactions between cells and substrates governing morphological transitions in the osteoblast compartment remain largely obscure. Here we show that osteoblast cultured in basement membrane matrix (Matrigel™) exhibits significant morphological changes after ten days of culture, and we decided to exploit this situation to investigate the molecular mechanisms responsible for guiding osteoblast morphological transitions. As almost all aspects of cellular physiology are under control of kinases, we generated more or less comprehensive cellular kinome profiles employing PepChip peptide arrays that contain over 1000 consensus substrates of kinase peptide. The results obtained were used to construct interactomes, and these revealed an important role for FoxO in mediating morphological changes of osteoblast, which was validated by Western blot technology when FoxO was significantly up-expressed in response to Matrigel™. As FoxO is a critical protein in canonical hedgehog signalling, we decided to explore the possible involvement of hedgehog signalling during osteoblast morphological changes. It appeared that osteoblast culture in Matrigel™ stimulates release of a substantial amounts Shh while concomitantly inducing upregulation of the expression of the bona fide hedgehog target genes Gli-1 and Patched. Functional confirmation of the relevance of these results for osteoblast morphological transitions came from experiments in which Shh hedgehog signalling was inhibited using the well-established pathway inhibitor cyclopamine (Cyc). In the presence of Cyc, culture of osteoblasts in Matrigel™ is not capable of inducing morphological changes but appears to provoke a proliferative response as evident from the upregulation of Cyclin D3 and cdk4. The most straightforward interpretation of our results is that hedgehog signalling is both necessary and sufficient for membrane matrix-based morphological transitions. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

Nuances of Morphology in Myelodysplastic Diseases in the Age of Molecular Diagnostics.

PubMed

Shaver, Aaron C; Seegmiller, Adam C

2017-10-01

Morphologic dysplasia is an important factor in diagnosis of myelodysplastic syndrome (MDS). However, the role of dysplasia is changing as new molecular genetic and genomic technologies take a more prominent place in diagnosis. This review discusses the role of morphology in the diagnosis of MDS and its interactions with cytogenetic and molecular testing. Recent changes in diagnostic criteria have attempted to standardize approaches to morphologic diagnosis of MDS, recognizing significant inter-observer variability in assessment of dysplasia. Definitive correlates between cytogenetic/molecular and morphologic findings have been described in only a small set of cases. However, these genetic and morphologic tools do play a complementary role in the diagnosis of both MDS and other myeloid neoplasms. Diagnosis of MDS requires a multi-factorial approach, utilizing both traditional morphologic as well as newer molecular genetic techniques. Understanding these tools, and the interplay between them, is crucial in the modern diagnosis of myeloid neoplasms.

Welfare maximisation in public transport : an analysis of the development in 7 Norwegian cities : summary

DOT National Transportation Integrated Search

2001-01-01

Framework conditions for Norwegian public transport have changed substantially over : the past two decades. Operating subsidies in Norwegian conurbations have been cut : dramatically. Changes in the Transport Act, which allowed for competitive tender...

Cytoskeletal perturbation induced by herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T).

PubMed

Zhao, Y; Li, W; Chou, I N

1987-01-01

To understand the mechanisms of toxicity of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), we have studied their effects on the cytoskeletal organization, particularly microtubules (MT) and microfilaments (MF), DNA synthesis, and the synthesis and composition of cytoskeletal proteins in mouse 3T3 cells. Exposure of cells to 2,4-D or 2,4,5-T resulted in a dose-dependent inhibition of DNA synthesis; 50% inhibition occurred at 2.21 mM and 0.90 mM for 2,4-D and 2,4,5-T, respectively. Furthermore, a strong synergistic inhibition of DNA synthesis was produced by mixtures (each having a total concentration of 1.25 mM) of 2,4-D with 2,4,5-T. Similarly, 2,4,5-T is more potent than 2,4-D in causing cytoskeletal perturbation as revealed by fluorescence microscopy. Treatment of cells with 2,4-D (2.5 mM) or 2,4,5-T (1.25 mM) for 20 h resulted in severe MT aggregation and the appearance of large bundles, which were organized in a rope-like structure in the former and a dramatic octopus-like pattern in the latter. Further, MT bundling is particularly severe in the cell center. Under these conditions, marked changes in MF organization also occurred as evidenced by clustering and crisscrossing of MF in the perinuclear region. A 1:1 mixture (final = 1.25 mM) of 2,4-D and 2,4,5-T, a formulation equivalent to Agent Orange composition, also induced a dramatic perturbation to the organization of MT and MF, resulting in the formation of ring-like structures. MT bundling is still apparent, especially around the outer edge of the "rings." MF are localized predominantly along the cell periphery, where they appear to be aggregated tightly forming patches. Surprisingly, the synthesis and composition of cytoskeletal proteins, which are resistant to detergent extraction but released by CaCl2, are essentially unaffected by 2,4-D or 2,4,5-T. These results suggest that the dramatic perturbation of the cytoskeletal morphology caused by these herbicides probably only results from a structural reorganization and redistribution of MT and MF.

The Functional Anatomy of Nerves Innervating the Ventral Grooved Blubber of Fin Whales (Balaenoptera Physalus).

PubMed

Vogl, Wayne; Petersen, Hannes; Adams, Arlo; Lillie, Margo A; Shadwick, Robert E

2017-11-01

Nerves that supply the floor of the oral cavity in rorqual whales are extensible to accommodate the dramatic changes in tissue dimensions that occur during "lunge feeding" in this group. We report here that the large nerves innervating the muscle component of the ventral grooved blubber (VGB) in fin whales are branches of cranial nerve VII (facial nerve). Therefore, the muscles of the VGB are homologous to second branchial arch derived muscles, which in humans include the muscles of "facial expression." We speculate, based on the presence of numerous foramina on the dorsolateral surface of the mandibular bones, that general sensation from the VGB likely is carried by branches of the mandibular division (V3) of cranial nerve V (trigeminal nerve), and that these small branches travel in the lipid-rich layer directly underlying the skin. We show that intercostal and phrenic nerves, which are not extensible, have a different wall and nerve core morphology than the large VGB nerves that are branches of VII. Although these VGB nerves are known to have two levels of waviness, the intercostal and phrenic nerves have only one in which the nerve fascicles in the nerve core are moderately wavy. In addition, the VGB nerves have inner and outer parts to their walls with numerous large elastin fibers in the outer part, whereas intercostal and phrenic nerves have single walls formed predominantly of collagen. Our results illustrate that overall nerve morphology depends greatly on location and the forces to which the structures are exposed. Anat Rec, 300:1963-1972, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Expression Levels of ALA Dehydratase as a Marker of ALA-PDT Efficacy

NASA Astrophysics Data System (ADS)

Avital, Schauder; Tamar, Feuerstein; Zvi, Malik

2010-05-01

Accelerated synthesis of protoporphyrinIX (PpIX) following ALA pre-treatment followed by light irradiation is the principle of ALA-PDT. Several limiting enzymes were suggested to control PpIX accumulation and PDT efficacy, among them porphobilinogen deaminase (PBGD) and ferrochelatase. Here we reveal the centrality of ALA dehydratase (ALAD) activity in predicting ALA-PDT efficacy. Silencing of ALAD expression and activity was carried out in leukemic cells using shRNA plasmid transfection or Pb2+ intoxication. ALAD activity, porphyrin synthesis and mitochondrial activity were determined versus PDT efficacy. In K562 ALAD-silenced cells, ALAD activity and expression were reduced and as a result, PpIX synthesis was almost abolished. Following ALA treatment and irradiation, ALAD-silenced cells depicted normal mitochondrial activity, in contrast to control and non-silencing transfected cells where accumulated PpIX and irradiation caused ROS formation and mitochondrial damage. Morphological analysis by scanning electron microscopy (SEM) of ALA-PDT treated cells showed no morphological changes in ALAD-silenced cells, while controls exhibited cell deformations and lysis. Annexin V-FITC/PI staining as well as LDH-L leakage testing showed that membrane integrity was undamaged following ALA-PDT in ALAD silenced cells. Pb2+ treatment in MEL cells impaired ALAD activity and reduced PpIX synthesis but to a lesser extent. In conclusion, we show that a dramatic reduction in PpIX accumulation following down regulation of ALAD expression prevents an efficient PDT. Thus, ALAD has a major role in regulating PpIX synthesis and ALA-PDT therapeutic outcome. Monitoring ALAD expression or activity in various tumors may be useful as prognostic tool to predict PDT efficacy.

Brief communication: Lumbar lordosis in extinct hominins: implications of the pelvic incidence.

PubMed

Been, Ella; Gómez-Olivencia, Asier; Kramer, Patricia A

2014-06-01

Recently, interest has peaked regarding the posture of extinct hominins. Here, we present a new method of reconstructing lordosis angles of extinct hominin specimens based on pelvic morphology, more specifically the orientation of the sacrum in relation to the acetabulum (pelvic incidence). Two regression models based on the correlation between pelvic incidence and lordosis angle in living hominoids have been developed. The mean values of the calculated lordosis angles based on these models are 36°-45° for australopithecines, 45°-47° for Homo erectus, 27°-34° for the Neandertals and the Sima de los Huesos hominins, and 49°-51° for fossil H. sapiens. The newly calculated lordosis values are consistent with previously published values of extinct hominins (Been et al.: Am J Phys Anthropol 147 (2012) 64-77). If the mean values of the present nonhuman hominoids are representative of the pelvic and lumbar morphology of the last common ancestor between humans and nonhuman hominoids, then both pelvic incidence and lordosis angle dramatically increased during hominin evolution from 27° ± 5 to 22° ± 3 (respectively) in nonhuman hominoids to 54° ± 10 and 51° ± 11 in modern humans. This change to a more human-like configuration appeared early in the hominin evolution as the pelvis and spines of both australopithecines and H. erectus show a higher pelvic incidence and lordosis angle than nonhuman hominoids. The Sima de los Huesos hominins and Neandertals show a derived configuration with a low pelvic incidence and lordosis angle. Copyright © 2014 Wiley Periodicals, Inc.

Designing a Binding Interface for Control of Cancer Cell Adhesion via 3D Topography and Metabolic Oligosaccharide Engineering

PubMed Central

Du, Jian; Che, Pao-Lin; Wang, Zhi-Yun; Aich, Udayanath; Yarema, Kevin J.

2011-01-01

This study combines metabolic oligosaccharide engineering (MOE), a technology where the glycocalyx of living cells is endowed with chemical features not normally found in sugars, with custom-designed three dimensional biomaterial substrates to enhance the adhesion of cancer cells and control their morphology and gene expression. Specifically, Ac5ManNTGc, a thiol-bearing analogue of N-acetyl-d-mannosamine (ManNAc) was used to introduce thiolated sialic acids into the glycocalyx of human Jurkat T-lymphoma derived cells. In parallel 2D films and 3D electrospun nanofibrous scaffolds were prepared from polyethersulfone (PES) and (as controls) left unmodified or aminated. Alternately, the materials were malemided or gold-coated to provide bioorthogonal binding partners for the thiol groups newly expressed on the cell surface. Cell attachment was modulated by both the topography of the substrate surface and by the chemical compatibility of the binding interface between the cell and the substrate; a substantial increase in binding for normally non-adhesive Jurkat line for 3D scaffold compared to 2D surfaces with an added degree of adhesion resulting from chemoselective binding to malemidede-derivatived or gold-coated surfaces. In addition, the morphology of the cells attached to the 3D scaffolds via MOE-mediated adhesion was dramatically altered and the expression of genes involved in cell adhesion changed in a time-dependent manner. This study showed that cell adhesion could be enhanced, gene expression modulated, and cell fate controlled by introducing the 3D topograhical cues into the growth substrate and by creating a glycoengineered binding interface where the chemistry of both the cell surface and biomaterials scaffold was controlled to facilitate a new mode of carbohydrate-mediated adhesion. PMID:21549424

Development of Semicrystalline Morphology of Poly(L-lactic acid) During Processing of a Vascular Scaffold

NASA Astrophysics Data System (ADS)

Ailianou, Artemis

New and promising treatments for coronary heart disease are enabled by vascular scaffolds made of poly(L-lactic acid) (PLLA), as demonstrated by Abbott Vascular's bioresorbable vascular scaffold. PLLA is a semicrystalline polymer whose degree of crystallinity and crystalline microstructure depend on the thermal and deformation history during processing. In turn, the semicrystalline morphology determines scaffold strength and biodegradation time. However, spatially-resolved information about the resulting material structure (crystallinity and crystal orientation) is needed to interpret in vivo observations. The first manufacturing step of the scaffold is tube expansion in a process similar to injection blow molding. Spatial uniformity of the tube microstructure is essential for the consistent production and performance of the final scaffold. For implantation into the artery, solid-state deformation below the glass transition temperature is imposed on a laser-cut subassembly to crimp it into a small diameter. Regions of localized strain during crimping are implicated in deployment behavior. To examine the semicrystalline microstructure development of the scaffold, we employed complementary techniques of scanning electron and polarized light microscopy, wide-angle X-ray scattering, and X-ray microdiffraction. These techniques enabled us to assess the microstructure at the micro and nano length scale. The results show that the expanded tube is very uniform in the azimuthal and axial directions and that radial variations are more pronounced. The crimping step dramatically changes the microstructure of the subassembly by imposing extreme elongation and compression. Spatial information on the degree and direction of chain orientation from X-ray microdiffraction data gives insight into the mechanism by which the PLLA dissipates the stresses during crimping, without fracture. Finally, analysis of the microstructure after deployment shows that it is inherited from the crimping step and contributes to the scaffold's successful implantation in vivo.

Dynamic expression of ancient and novel molluscan shell genes during ecological transitions

PubMed Central

Jackson, Daniel J; Wörheide, Gert; Degnan, Bernard M

2007-01-01

Background The Mollusca constitute one of the most morphologically and ecologically diverse metazoan phyla, occupying a wide range of marine, terrestrial and freshwater habitats. The evolutionary success of the molluscs can in part be attributed to the evolvability of the external shell. Typically, the shell first forms during embryonic and larval development, changing dramatically in shape, colour and mineralogical composition as development and maturation proceeds. Major developmental transitions in shell morphology often correlate with ecological transitions (e.g. from a planktonic to benthic existence at metamorphosis). While the genes involved in molluscan biomineralisation are beginning to be identified, there is little understanding of how these are developmentally regulated, or if the same genes are operational at different stages of the mollusc's life. Results Here we relate the developmental expression of nine genes in the tissue responsible for shell production – the mantle – to ecological transitions that occur during the lifetime of the tropical abalone Haliotis asinina (Vetigastropoda). Four of these genes encode evolutionarily ancient proteins, while four others encode secreted proteins with little or no identity to known proteins. Another gene has been previously described from the mantle of another haliotid vetigastropod. All nine genes display dynamic spatial and temporal expression profiles within the larval shell field and juvenile mantle. Conclusion These expression data reflect the regulatory complexity that underlies molluscan shell construction from larval stages to adulthood, and serves to highlight the different ecological demands placed on each stage. The use of both ancient and novel genes in all stages of shell construction also suggest that a core set of shell-making genes was provided by a shared metazoan ancestor, which has been elaborated upon to produce the range of molluscan shell types we see today. PMID:17845714

Welding of Semiconductor Nanowires by Coupling Laser-Induced Peening and Localized Heating.

PubMed

Rickey, Kelly M; Nian, Qiong; Zhang, Genqiang; Chen, Liangliang; Suslov, Sergey; Bhat, S Venkataprasad; Wu, Yue; Cheng, Gary J; Ruan, Xiulin

2015-11-03

We demonstrate that laser peening coupled with sintering of CdTe nanowire films substantially enhances film quality and charge transfer while largely maintaining basic particle morphology. During the laser peening phase, a shockwave is used to compress the film. Laser sintering comprises the second step, where a nanosecond pulse laser beam welds the nanowires. Microstructure, morphology, material content, and electrical conductivities of the films are characterized before and after treatment. The morphology results show that laser peening can decrease porosity and bring nanowires into contact, and pulsed laser heating fuses those contacts. Multiphysics simulations coupling electromagnetic and heat transfer modules demonstrate that during pulsed laser heating, local EM field enhancement is generated specifically around the contact areas between two semiconductor nanowires, indicating localized heating. The characterization results indicate that solely laser peening or sintering can only moderately improve the thin film quality; however, when coupled together as laser peen sintering (LPS), the electrical conductivity enhancement is dramatic. LPS can decrease resistivity up to a factor of ~10,000, resulting in values on the order of ~10(5) Ω-cm in some cases, which is comparable to CdTe thin films. Our work demonstrates that LPS is an effective processing method to obtain high-quality semiconductor nanocrystal films.

Ecological specialization and morphological diversification in Greater Antillean boas.

PubMed

Reynolds, R Graham; Collar, David C; Pasachnik, Stesha A; Niemiller, Matthew L; Puente-Rolón, Alberto R; Revell, Liam J

2016-08-01

Colonization of islands can dramatically influence the evolutionary trajectories of organisms, with both deterministic and stochastic processes driving adaptation and diversification. Some island colonists evolve extremely large or small body sizes, presumably in response to unique ecological circumstances present on islands. One example of this phenomenon, the Greater Antillean boas, includes both small (<90 cm) and large (4 m) species occurring on the Greater Antilles and Bahamas, with some islands supporting pairs or trios of body-size divergent species. These boas have been shown to comprise a monophyletic radiation arising from a Miocene dispersal event to the Greater Antilles, though it is not known whether co-occurrence of small and large species is a result of dispersal or in situ evolution. Here, we provide the first comprehensive species phylogeny for this clade combined with morphometric and ecological data to show that small body size evolved repeatedly on separate islands in association with specialization in substrate use. Our results further suggest that microhabitat specialization is linked to increased rates of head shape diversification among specialists. Our findings show that ecological specialization following island colonization promotes morphological diversity through deterministic body size evolution and cranial morphological diversification that is contingent on island- and species-specific factors. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Effects of alloy heat treatment on oxidation kinetics and scale morphology for Crofer 22 APU

NASA Astrophysics Data System (ADS)

Magdefrau, Neal J.; Chen, Lei; Sun, Ellen Y.; Aindow, Mark

2013-11-01

The effect of alloy heat treatment on the oxidation kinetics and oxide scale microstructure of Crofer 22 APU has been studied. Parabolic oxidation rate constants were measured for the as-received alloy and after pre-oxidation heat treatment in argon at 1050 °C for 1 and 4 h. The oxide scale microstructure was investigated using scanning electron microscopy, focused ion beam milling and transmission electron microscopy. It was found that the alloy forms a two-layer scale with a continuous chromia layer and a discontinuous MnCr2O4 overlayer. Two forms of internal oxides were also formed: subscale pockets of spinel and isolated TiOx precipitates in the underlying alloy. The pre-oxidation heat treatment had a profound effect on the grain size and morphology of the Cr2O3 and MnCr2O4 layers in the scale. The heat-treated samples exhibit a 3.5× lower parabolic oxidation rate constant than the as-received Crofer 22 APU. This improvement in oxidation resistance is attributed to the dramatic differences in the morphology of the oxide scale that forms during the earliest stages of oxidation (<5 h). The implications of these findings for oxidation mechanisms and long-term SOFC performance are discussed.

Welding of Semiconductor Nanowires by Coupling Laser-Induced Peening and Localized Heating

PubMed Central

Rickey, Kelly M.; Nian, Qiong; Zhang, Genqiang; Chen, Liangliang; Suslov, Sergey; Bhat, S. Venkataprasad; Wu, Yue; Cheng, Gary J.; Ruan, Xiulin

2015-01-01

We demonstrate that laser peening coupled with sintering of CdTe nanowire films substantially enhances film quality and charge transfer while largely maintaining basic particle morphology. During the laser peening phase, a shockwave is used to compress the film. Laser sintering comprises the second step, where a nanosecond pulse laser beam welds the nanowires. Microstructure, morphology, material content, and electrical conductivities of the films are characterized before and after treatment. The morphology results show that laser peening can decrease porosity and bring nanowires into contact, and pulsed laser heating fuses those contacts. Multiphysics simulations coupling electromagnetic and heat transfer modules demonstrate that during pulsed laser heating, local EM field enhancement is generated specifically around the contact areas between two semiconductor nanowires, indicating localized heating. The characterization results indicate that solely laser peening or sintering can only moderately improve the thin film quality; however, when coupled together as laser peen sintering (LPS), the electrical conductivity enhancement is dramatic. LPS can decrease resistivity up to a factor of ~10,000, resulting in values on the order of ~105 Ω-cm in some cases, which is comparable to CdTe thin films. Our work demonstrates that LPS is an effective processing method to obtain high-quality semiconductor nanocrystal films. PMID:26527570

Monodisperse spindle-like FeWO{sub 4} nanoparticles: Controlled hydrothermal synthesis and enhanced optical properties

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

Guo, Jinxue; Zhou, Xiaoyu; Lu, Yibin

2012-12-15

Monodisperse FeWO{sub 4} nanoparticles with specific spindle-like morphology have been synthesized in the presence of citric acid through hydrothermal process. In the synthesis route, citric acid played four roles such as the reducing agent, chelating regents, structure-directing agent and stabilizing agents. In addition, the morphology of FeWO{sub 4} was dramatically tuned by the pH value of the precursor medium. The optical properties of FeWO{sub 4} were investigated with UV-Vis spectra and photoluminescence spectroscopy. The photocatalytic experiments demonstrated that the decomposition efficiency of the monodisperse spindle-like FeWO{sub 4} nanoparticles is 74% after 30 min of UV irradiation, which displayed remarkable enhancedmore » photodegradation activity compared with ordinary FeWO{sub 4} sample (57%) and normal TiO{sub 2} photocatalysts P-25 (56%). - Monodisperse spindle-like FeWO{sub 4} nanoparticles with enhanced photocatalytic activities. Highlights: Black-Right-Pointing-Pointer Monodisperse spindle-like FeWO{sub 4} were synthesized with hydrothermal method. Black-Right-Pointing-Pointer Citric acid plays key roles in the hydrothermal synthesis. Black-Right-Pointing-Pointer Their morphology can be tuned with pH value of the precursor medium. Black-Right-Pointing-Pointer They show enhanced photocatalytic activities with irradiation of UV light.« less

Effects of dimethyl sulfoxide on the morphology and viability of primary cultured neurons and astrocytes.

PubMed

Zhang, Chen; Deng, Yuanying; Dai, Hongmei; Zhou, Wenjuan; Tian, Jing; Bing, Guoying; Zhao, Lingling

2017-01-01

Dimethyl sulfoxide (DMSO) is a widely used solvent and vehicle for in vivo and in vitro administration of test compounds. Effects of DMSO independent of the test compound, such as in studies examining morphological plasticity or neurotoxic responses, may lead to spurious results. To investigate effects of DMSO concentration ([DMSO]) on morphology and survival of primary cultured neurons and astrocytes. Primary cultured neurons and astrocytes were treated with 0.25%-10.00% [DMSO] for 12-48h. Viable cell number and morphology were compared to untreated cultures using the CCK-8 assay and phase-contrast microscopy. Expression levels of the neuronal marker NeuN and astrocyte marker glial fibrillary acidic protein (GFAP) were determined by immunofluorescence and western blotting. A [DMSO]≤0.50% had no effect on neuronal number or NeuN expression up to 24h, while ≥1.00% induced a progressive and dramatic loss of both viability and NeuN expression even after 12h. Brief (12h) exposure to ≤1.00% DMSO had no effect on astrocytes survival or GFAP expression, while ≥5.00% significantly reduced both at all exposure durations. In contrast to neurons, exposure to 0.50% and 1.00% DMSO for 24 or 48h enhanced astrocytes proliferation and GFAP expression. Astrocytic processes were maintained at 0.50% and 1.00% DMSO, while neurons exhibited marked neurite retraction at ≥0.50%. A [DMSO]≥0.5% markedly disrupts neuronal morphology and reduces viability, even after brief exposure. In astrocytes, 0.50% and 1.00% DMSO appear to induce reactive gliosis. For treatment of neural cells, [DMSO] should be ≤0.25% to obviate spurious vehicle effects. Copyright © 2016 Elsevier Inc. All rights reserved.

Simulating galaxies in the reionization era with FIRE-2: morphologies and sizes

NASA Astrophysics Data System (ADS)

Ma, Xiangcheng; Hopkins, Philip F.; Boylan-Kolchin, Michael; Faucher-Giguère, Claude-André; Quataert, Eliot; Feldmann, Robert; Garrison-Kimmel, Shea; Hayward, Christopher C.; Kereš, Dušan; Wetzel, Andrew

2018-06-01

We study the morphologies and sizes of galaxies at z ≥ 5 using high-resolution cosmological zoom-in simulations from the Feedback In Realistic Environments project. The galaxies show a variety of morphologies, from compact to clumpy to irregular. The simulated galaxies have more extended morphologies and larger sizes when measured using rest-frame optical B-band light than rest-frame UV light; sizes measured from stellar mass surface density are even larger. The UV morphologies are usually dominated by several small, bright young stellar clumps that are not always associated with significant stellar mass. The B-band light traces stellar mass better than the UV, but it can also be biased by the bright clumps. At all redshifts, galaxy size correlates with stellar mass/luminosity with large scatter. The half-light radii range from 0.01 to 0.2 arcsec (0.05-1 kpc physical) at fixed magnitude. At z ≥ 5, the size of galaxies at fixed stellar mass/luminosity evolves as (1 + z)-m, with m ˜ 1-2. For galaxies less massive than M* ˜ 108 M⊙, the ratio of the half-mass radius to the halo virial radius is ˜ 10 per cent and does not evolve significantly at z = 5-10; this ratio is typically 1-5 per cent for more massive galaxies. A galaxy's `observed' size decreases dramatically at shallower surface brightness limits. This effect may account for the extremely small sizes of z ≥ 5 galaxies measured in the Hubble Frontier Fields. We provide predictions for the cumulative light distribution as a function of surface brightness for typical galaxies at z = 6.

On the holographic 3D tracking of in vitro cells characterized by a highly-morphological change.

PubMed

Memmolo, Pasquale; Iannone, Maria; Ventre, Maurizio; Netti, Paolo Antonio; Finizio, Andrea; Paturzo, Melania; Ferraro, Pietro

2012-12-17

Digital Holography (DH) in microscopic configuration is a powerful tool for the imaging of micro-objects contained into a three dimensional (3D) volume, by a single-shot image acquisition. Many studies report on the ability of DH to track particle, microorganism and cells in 3D. However, very few investigations are performed with objects that change severely their morphology during the observation period. Here we study DH as a tool for 3D tracking an osteosarcoma cell line for which extensive changes in cell morphology are associated to cell motion. Due to the great unpredictable morphological change, retrieving cell's position in 3D can become a complicated issue. We investigate and discuss in this paper how the tridimensional position can be affected by the continuous change of the cells. Moreover we propose and test some strategies to afford the problems and compare it with others approaches. Finally, results on the 3D tracking and comments are reported and illustrated.

Physical linkages between an offshore canyon and surf zone morphologic change

NASA Astrophysics Data System (ADS)

Hansen, Jeff E.; Raubenheimer, Britt; Elgar, Steve; List, Jeffrey H.; Lippmann, Thomas C.

2017-04-01

The causes of surf zone morphologic changes observed along a sandy beach onshore of a submarine canyon were investigated using field observations and a numerical model (Delft3D/SWAN). Numerically simulated morphologic changes using four different sediment transport formulae reproduce the temporal and spatial patterns of net cross-shore integrated (between 0 and 6.5 m water depths) accretion and erosion observed in a ˜300 m alongshore region, a few hundred meters from the canyon head. The observations and simulations indicate that the accretion or erosion results from converging or diverging alongshore currents driven primarily by breaking waves and alongshore pressure gradients. The location of convergence or divergence depends on the direction of the offshore waves that refract over the canyon, suggesting that bathymetric features on the inner shelf can have first-order effects on short-term nearshore morphologic change.

Hidden dental diversity in the oldest terrestrial apex predator Dimetrodon.

PubMed

Brink, Kirstin S; Reisz, Robert R

2014-01-01

Paleozoic sphenacodontid synapsids are the oldest known fully terrestrial apex predators. Dimetrodon and other sphenacodontids are the first terrestrial vertebrates to have strong heterodonty, massive skulls and well-developed labio-lingually compressed and recurved teeth with mesial and distal cutting edges (carinae). Here we reveal that the dentition of Dimetrodon and other sphenacodontids is diverse. Tooth morphology includes simple carinae with smooth cutting edges and elaborate enamel features, including the first occurrence of cusps and true denticles (ziphodonty) in the fossil record. A time-calibrated phylogenetic analysis indicates that changes in dental morphology occur in the absence of any significant changes in skull morphology, suggesting that the morphological change is associated with changes in feeding style and trophic interactions in these ecosystems. In addition, the available evidence indicates that ziphodonty evolved for the first time in the largest known species of the genus Dimetrodon and independently from the ziphodont teeth observed in some therapsids.

Assessing climate change impacts on soil salinity development with proximal and satellite sensors

USDA-ARS?s Scientific Manuscript database

Changes in climate patterns have dramatically influenced some agricultural areas. Examples include the historic 5-year drought in California’s San Joaquin Valley (SJV) and the 20-year above average annual rainfall in the Red River Valley (RRV) of the Midwestern USA. Climate change may have impacted ...

Birth Cohort Changes in Chinese College Students' Loneliness and Social Support

ERIC Educational Resources Information Center

Xin, Sufei; Xin, Ziqiang

2016-01-01

With the dramatic recent changes in Chinese society, Chinese college students' average levels of loneliness and social support might also have changed across their birth cohorts. The present cross-temporal meta-analysis of 56 studies (N = 21,541) found that Chinese college students' scores on the UCLA Loneliness Scale (Version 3) increased…

Drama and Routine in the Public Schools.

ERIC Educational Resources Information Center

Pondy, Louis R.; Huff, Anne S.

A case study of curricular change compares two leading models of organizational change. One model stresses the uncertainty and disorder of major changes and views them as dramatic events. The other model sees major organizational shifts as the result of ordinary day-to-day processes and emphasizes their routine nature. For this study, the…