Linking Leadership to Student Learning

ERIC Educational Resources Information Center

Leithwood, Kenneth; Seashore-Louis, Karen

2011-01-01

"Linking Leadership to Student Learning" clearly shows how school leadership improves student achievement. The book is based on an ambitious five-year study on educational leadership that was sponsored by The Wallace Foundation. The authors studied 43 districts, across 9 states and 180 elementary, middle, and secondary schools. In this book,…

Preserved Self-Other Distinction during Empathy in Autism Is Linked to Network Integrity of Right Supramarginal Gyrus

ERIC Educational Resources Information Center

Hoffmann, Ferdinand; Koehne, Svenja; Steinbeis, Nikolaus; Dziobek, Isabel; Singer, Tania

2016-01-01

Autism spectrum disorder (ASD) shows deficits in self-other distinction during theory of mind (ToM). Here we investigated whether ASD patients also show difficulties in self-other distinction during empathy and if potential deficits are linked to dysfunctional resting-state connectivity patterns. In a first study, ASD patients and controls…

Computational investigation of kinetics of cross-linking reactions in proteins: importance in structure prediction.

PubMed

Bandyopadhyay, Pradipta; Kuntz, Irwin D

2009-01-01

The determination of protein structure using distance constraints is a new and promising field of study. One implementation involves attaching residues of a protein using a cross-linking agent, followed by protease digestion, analysis of the resulting peptides by mass spectroscopy, and finally sequence threading to detect the protein folds. In the present work, we carry out computational modeling of the kinetics of cross-linking reactions in proteins using the master equation approach. The rate constants of the cross-linking reactions are estimated using the pKas and the solvent-accessible surface areas of the residues involved. This model is tested with fibroblast growth factor (FGF) and cytochrome C. It is consistent with the initial experimental rate data for individual lysine residues for cytochrome C. Our model captures all observed cross-links for FGF and almost 90% of the observed cross-links for cytochrome C, although it also predicts cross-links that were not observed experimentally (false positives). However, the analysis of the false positive results is complicated by the fact that experimental detection of cross-links can be difficult and may depend on specific experimental conditions such as pH, ionic strength. Receiver operator characteristic plots showed that our model does a good job in predicting the observed cross-links. Molecular dynamics simulations showed that for cytochrome C, in general, the two lysines come closer for the observed cross-links as compared to the false positive ones. For FGF, no such clear pattern exists. The kinetic model and MD simulation can be used to study proposed cross-linking protocols.

Synthesis and binding affinity analysis of α1-2- and α1-6-O/S-linked dimannosides for the elucidation of sulfur in glycosidic bonds using quartz crystal microbalance sensors.

PubMed

Norberg, Oscar; Wu, Bin; Thota, Niranjan; Ge, Jian-Tao; Fauquet, Germain; Saur, Ann-Kathrin; Aastrup, Teodor; Dong, Hai; Yan, Mingdi; Ramström, Olof

2017-11-27

The role of sulfur in glycosidic bonds has been evaluated using quartz crystal microbalance methodology. Synthetic routes towards α1-2- and α1-6-linked dimannosides with S- or O-glycosidic bonds have been developed, and the recognition properties assessed in competition binding assays with the cognate lectin concanavalin A. Mannose-presenting QCM sensors were produced using photoinitiated, nitrene-mediated immobilization methods, and the subsequent binding study was performed in an automated flow-through instrumentation, and correlated with data from isothermal titration calorimetry. The recorded K d -values corresponded well with reported binding affinities for the O-linked dimannosides with affinities for the α1-2-linked dimannosides in the lower micromolar range. The S-linked analogs showed slightly disparate effects, where the α1-6-linked analog showed weaker affinity than the O-linked dimannoside, as well as positive apparent cooperativity, whereas the α1-2-analog displayed very similar binding compared to the O-linked structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhancing robustness of interdependent network by adding connectivity and dependence links

NASA Astrophysics Data System (ADS)

Cui, Pengshuai; Zhu, Peidong; Wang, Ke; Xun, Peng; Xia, Zhuoqun

2018-05-01

Enhancing robustness of interdependent networks by adding connectivity links has been researched extensively, however, few of them are focusing on adding both connectivity and dependence links to enhance robustness. In this paper, we aim to study how to allocate the limited costs reasonably to add both connectivity and dependence links. Firstly, we divide the attackers into stubborn attackers and smart attackers according to whether would they change their attack modes with the changing of network structure; Then by simulations, link addition strategies are given separately according to different attackers, with which we can allocate the limited costs to add connectivity links and dependence links reasonably and achieve more robustness than only adding connectivity links or dependence links. The results show that compared to only adding connectivity links or dependence links, allocating the limited resources reasonably and adding both connectivity links and dependence links could bring more robustness to the interdependent networks.

Measures of health sciences journal use: a comparison of vendor, link-resolver, and local citation statistics*

PubMed Central

De Groote, Sandra L.; Blecic, Deborah D.; Martin, Kristin

2013-01-01

Objective: Libraries require efficient and reliable methods to assess journal use. Vendors provide complete counts of articles retrieved from their platforms. However, if a journal is available on multiple platforms, several sets of statistics must be merged. Link-resolver reports merge data from all platforms into one report but only record partial use because users can access library subscriptions from other paths. Citation data are limited to publication use. Vendor, link-resolver, and local citation data were examined to determine correlation. Because link-resolver statistics are easy to obtain, the study library especially wanted to know if they correlate highly with the other measures. Methods: Vendor, link-resolver, and local citation statistics for the study institution were gathered for health sciences journals. Spearman rank-order correlation coefficients were calculated. Results: There was a high positive correlation between all three data sets, with vendor data commonly showing the highest use. However, a small percentage of titles showed anomalous results. Discussion and Conclusions: Link-resolver data correlate well with vendor and citation data, but due to anomalies, low link-resolver data would best be used to suggest titles for further evaluation using vendor data. Citation data may not be needed as it correlates highly with other measures. PMID:23646026

Evaluation of inertial devices for the control of large, flexible, space-based telerobotic arms

NASA Technical Reports Server (NTRS)

Montgomery, Raymond C.; Kenny, Sean P.; Ghosh, Dave; Shenhar, Joram

1993-01-01

Inertial devices, including sensors and actuators, offer the potential of improving the tracking of telerobotic commands for space-based robots by smoothing payload motions and suppressing vibrations. In this paper, inertial actuators (specifically, torque-wheels and reaction-masses) are studied for that potential application. Batch simulation studies are presented which show that torque-wheels can reduce the overshoot in abrupt stop commands by 82 percent for a two-link arm. For man-in-the-loop evaluation, a real-time simulator has been developed which samples a hand-controller, solves the nonlinear equations of motion, and graphically displays the resulting motion on a computer workstation. Currently, two manipulator models, a two-link, rigid arm and a single-link, flexible arm, have been studied. Results are presented which show that, for a single-link arm, a reaction-mass/torque-wheel combination at the payload end can yield a settling time of 3 s for disturbances in the first flexible mode as opposed to 10 s using only a hub motor. A hardware apparatus, which consists of a single-link, highly flexible arm with a hub motor and a torque-wheel, has been assembled to evaluate the concept and is described herein.

Evaluation of inertial devices for the control of large, flexible, space-based telerobotic arms

NASA Astrophysics Data System (ADS)

Montgomery, Raymond C.; Kenny, Sean P.; Ghosh, Dave; Shenhar, Joram

1993-02-01

Inertial devices, including sensors and actuators, offer the potential of improving the tracking of telerobotic commands for space-based robots by smoothing payload motions and suppressing vibrations. In this paper, inertial actuators (specifically, torque-wheels and reaction-masses) are studied for that potential application. Batch simulation studies are presented which show that torque-wheels can reduce the overshoot in abrupt stop commands by 82 percent for a two-link arm. For man-in-the-loop evaluation, a real-time simulator has been developed which samples a hand-controller, solves the nonlinear equations of motion, and graphically displays the resulting motion on a computer workstation. Currently, two manipulator models, a two-link, rigid arm and a single-link, flexible arm, have been studied. Results are presented which show that, for a single-link arm, a reaction-mass/torque-wheel combination at the payload end can yield a settling time of 3 s for disturbances in the first flexible mode as opposed to 10 s using only a hub motor. A hardware apparatus, which consists of a single-link, highly flexible arm with a hub motor and a torque-wheel, has been assembled to evaluate the concept and is described herein.

An auxiliary optimization method for complex public transit route network based on link prediction

NASA Astrophysics Data System (ADS)

Zhang, Lin; Lu, Jian; Yue, Xianfei; Zhou, Jialin; Li, Yunxuan; Wan, Qian

2018-02-01

Inspired by the missing (new) link prediction and the spurious existing link identification in link prediction theory, this paper establishes an auxiliary optimization method for public transit route network (PTRN) based on link prediction. First, link prediction applied to PTRN is described, and based on reviewing the previous studies, the summary indices set and its algorithms set are collected for the link prediction experiment. Second, through analyzing the topological properties of Jinan’s PTRN established by the Space R method, we found that this is a typical small-world network with a relatively large average clustering coefficient. This phenomenon indicates that the structural similarity-based link prediction will show a good performance in this network. Then, based on the link prediction experiment of the summary indices set, three indices with maximum accuracy are selected for auxiliary optimization of Jinan’s PTRN. Furthermore, these link prediction results show that the overall layout of Jinan’s PTRN is stable and orderly, except for a partial area that requires optimization and reconstruction. The above pattern conforms to the general pattern of the optimal development stage of PTRN in China. Finally, based on the missing (new) link prediction and the spurious existing link identification, we propose optimization schemes that can be used not only to optimize current PTRN but also to evaluate PTRN planning.

Multiple repair pathways mediate tolerance to chemotherapeutic cross-linking agents in vertebrate cells.

PubMed

Nojima, Kuniharu; Hochegger, Helfrid; Saberi, Alihossein; Fukushima, Toru; Kikuchi, Koji; Yoshimura, Michio; Orelli, Brian J; Bishop, Douglas K; Hirano, Seiki; Ohzeki, Mioko; Ishiai, Masamichi; Yamamoto, Kazuhiko; Takata, Minoru; Arakawa, Hiroshi; Buerstedde, Jean-Marie; Yamazoe, Mitsuyoshi; Kawamoto, Takuo; Araki, Kasumi; Takahashi, Jun A; Hashimoto, Nobuo; Takeda, Shunichi; Sonoda, Eiichiro

2005-12-15

Cross-linking agents that induce DNA interstrand cross-links (ICL) are widely used in anticancer chemotherapy. Yeast genetic studies show that nucleotide excision repair (NER), Rad6/Rad18-dependent postreplication repair, homologous recombination, and cell cycle checkpoint pathway are involved in ICL repair. To study the contribution of DNA damage response pathways in tolerance to cross-linking agents in vertebrates, we made a panel of gene-disrupted clones from chicken DT40 cells, each defective in a particular DNA repair or checkpoint pathway, and measured the sensitivities to cross-linking agents, including cis-diamminedichloroplatinum (II) (cisplatin), mitomycin C, and melphalan. We found that cells harboring defects in translesion DNA synthesis (TLS), Fanconi anemia complementation groups (FANC), or homologous recombination displayed marked hypersensitivity to all the cross-linking agents, whereas NER seemed to play only a minor role. This effect of replication-dependent repair pathways is distinctively different from the situation in yeast, where NER seems to play a major role in dealing with ICL. Cells deficient in Rev3, the catalytic subunit of TLS polymerase Polzeta, showed the highest sensitivity to cisplatin followed by fanc-c. Furthermore, epistasis analysis revealed that these two mutants work in the same pathway. Our genetic comprehensive study reveals a critical role for DNA repair pathways that release DNA replication block at ICLs in cellular tolerance to cross-linking agents and could be directly exploited in designing an effective chemotherapy.

Design and fabrication of a chitosan hydrogel with gradient structures via a step-by-step cross-linking process.

PubMed

Xu, Yongxiang; Yuan, Shenpo; Han, Jianmin; Lin, Hong; Zhang, Xuehui

2017-11-15

The development of scaffolds to mimic the gradient structure of natural tissue is an important consideration for effective tissue engineering. In the present study, a physical cross-linking chitosan hydrogel with gradient structures was fabricated via a step-by-step cross-linking process using sodium tripolyphosphate and sodium hydroxide as sequential cross-linkers. Chitosan hydrogels with different structures (single, double, and triple layers) were prepared by modifying the gelling process. The properties of the hydrogels were further adjusted by varying the gelling conditions, such as gelling time, pH, and composition of the crosslinking solution. Slight cytotoxicity was showed in MTT assay for hydrogels with uncross-linking chitosan solution and non-cytotoxicity was showed for other hydrogels. The results suggest that step-by-step cross-linking represents a practicable method to fabricate scaffolds with gradient structures. Copyright © 2017. Published by Elsevier Ltd.

Flight tests with a data link used for air traffic control information exchange

NASA Technical Reports Server (NTRS)

Knox, Charles E.; Scanlon, Charles H.

1991-01-01

Previous studies showed that air traffic control (ATC) message exchange with a data link offers the potential benefits of increased airspace system safety and efficiency. To accomplish these benefits, data link can be used to reduce communication errors and relieve overloaded ATC voice radio frequencies, which hamper efficient message exchange during peak traffic periods. Flight tests with commercial airline pilots as test subjects were conducted in the NASA Transport Systems Research Vehicle Boeing 737 airplane to contrast flight operations that used current voice communications with flight operations that used data link to transmit both strategic and tactical ATC clearances during a typical commercial airflight from takeoff to landing. The results of these tests that used data link as the primary communication source with ATC showed flight crew acceptance, a perceived reduction in crew work load, and a reduction in crew communication errors.

Transglutaminase catalyzed cross-linking of sodium caseinate improves oxidative stability of flaxseed oil emulsion.

PubMed

Ma, Hairan; Forssell, Pirkko; Kylli, Petri; Lampi, Anna-Maija; Buchert, Johanna; Boer, Harry; Partanen, Riitta

2012-06-20

Sodium caseinate was modified by transglutaminase catalyzed cross-linking reaction prior to the emulsification process in order to study the effect of cross-linking on the oxidative stability of protein stabilized emulsions. The extent of the cross-linking catalyzed by different dosages of transglutaminase was investigated by following the ammonia production during the reaction and using SDS-PAGE gel. O/W emulsions prepared with the cross-linked and non-cross-linked sodium caseinates were stored for 30 days under the same conditions. Peroxide value measurement, oxygen consumption measurement, and headspace gas chromatography analysis were used to study the oxidative stability of the emulsions. The emulsion made of the cross-linked sodium caseinate showed an improved oxidative stability with reduced formation of fatty acid hydroperoxides and volatiles and a longer period of low rate oxygen consumption. The improving effect of transglutaminase catalyzed cross-linking could be most likely attributed to the enhanced physical stability of the interfacial protein layer against competitive adsorption by oil oxidation products.

Matching-centrality decomposition and the forecasting of new links in networks.

PubMed

Rohr, Rudolf P; Naisbit, Russell E; Mazza, Christian; Bersier, Louis-Félix

2016-02-10

Networks play a prominent role in the study of complex systems of interacting entities in biology, sociology, and economics. Despite this diversity, we demonstrate here that a statistical model decomposing networks into matching and centrality components provides a comprehensive and unifying quantification of their architecture. The matching term quantifies the assortative structure in which node makes links with which other node, whereas the centrality term quantifies the number of links that nodes make. We show, for a diverse set of networks, that this decomposition can provide a tight fit to observed networks. Then we provide three applications. First, we show that the model allows very accurate prediction of missing links in partially known networks. Second, when node characteristics are known, we show how the matching-centrality decomposition can be related to this external information. Consequently, it offers us a simple and versatile tool to explore how node characteristics explain network architecture. Finally, we demonstrate the efficiency and flexibility of the model to forecast the links that a novel node would create if it were to join an existing network. © 2016 The Author(s).

Matching–centrality decomposition and the forecasting of new links in networks

PubMed Central

Rohr, Rudolf P.; Naisbit, Russell E.; Mazza, Christian; Bersier, Louis-Félix

2016-01-01

Networks play a prominent role in the study of complex systems of interacting entities in biology, sociology, and economics. Despite this diversity, we demonstrate here that a statistical model decomposing networks into matching and centrality components provides a comprehensive and unifying quantification of their architecture. The matching term quantifies the assortative structure in which node makes links with which other node, whereas the centrality term quantifies the number of links that nodes make. We show, for a diverse set of networks, that this decomposition can provide a tight fit to observed networks. Then we provide three applications. First, we show that the model allows very accurate prediction of missing links in partially known networks. Second, when node characteristics are known, we show how the matching–centrality decomposition can be related to this external information. Consequently, it offers us a simple and versatile tool to explore how node characteristics explain network architecture. Finally, we demonstrate the efficiency and flexibility of the model to forecast the links that a novel node would create if it were to join an existing network. PMID:26842568

Barney and Breakfast: Messages about Food and Eating in Preschool Television Shows and How They May Impact the Development of Eating Behaviours in Children

ERIC Educational Resources Information Center

Anderson, Leslie Margaret; Anderson, Jim

2010-01-01

Television viewing has been linked to the increasing problem of obesity in young children, as well as to the development of inappropriate eating behaviours, yet the mechanism behind this link remains unclear. This study investigated the messages about food and eating that appear in a sample of preschool children's television shows and found that…

Evaluation of performance and maximum length of continuous decks in bridges : part 2.

DOT National Transportation Integrated Search

2012-08-01

Field experimental measurements and analytical studies showed that the link-slab reinforcement : experiences almost no axial load due to thermal and gravity loading. One of the fundamental : reasons for the low loads in the link-slab reinforcement is...

Nanophotonic Devices in Silicon for Nonlinear Optics

DTIC Science & Technology

2010-10-15

record performance  Demonstration of world‟s lowest loss slot waveguides, made in a DOD-trusted foundry (BAE Systems)  Design study showing...highly-cited design study.  Design study on analog links using the above modulators.  Demonstration of the first silicon waveguides for the mid...Hochberg. Design of transmission line driven slot waveguide Mach-Zehnder interferometers and application to analog optical links. Optics Express 2010

Studies of the permeation properties of glomerular basement membrane: cross-linking renders glomerular basement membrane permeable to protein.

PubMed

Walton, H A; Byrne, J; Robinson, G B

1992-03-20

Cross-linking glomerular basement membrane (GBM) has been shown to render it more permeable to protein. Isolated pig GBM was cross-linked with dimethylmalonimidate which reacts selectively with lysine epsilon-NH2 groups or with glutaraldehyde, a less selective cross-linking agent. Studies of the ultrafiltration properties of these materials in vitro using cytochrome c, myoglobin, bovine serum albumin and immunoglobulin showed that cross-linking had markedly increased solvent and protein fluxes as compared with native membranes particularly at higher pressures. Filtration studies with serum demonstrated that the cross-linked membranes were more permeable to serum proteins. Thickness measurements under pressure indicated that cross-linked membrane was less compressed than native membrane as pressure was increased. Pore theory did not provide a suitable model for analysis of the results, but analysis of the results using the fibre-matrix hypothesis indicated that cross-linking had the effect of bundling together the fibres (type IV collagen) in the GBM matrix. The effect of cross-linking on filtration could be explained by a combination of contraction of the membrane, fibre bundling and increased rigidity compared with native membrane. Cross-linking of GBM might lead to long-term damage of the glomerular capillary wall in nephritis, so promoting proteinuria.

Analysis of glycation induced protein cross-linking inhibitory effects of some antidiabetic plants and spices.

PubMed

Perera, Handunge Kumudu Irani; Handuwalage, Charith Sandaruwan

2015-06-09

Protein cross-linking which occurs towards the latter part of protein glycation is implicated in the development of chronic diabetic complications. Glycation induced protein cross-linking inhibitory effects of nine antidiabetic plants and three spices were evaluated in this study using a novel, simple, electrophoresis based method. Methanol extracts of thirteen plants including nine antidiabetic plants and three spices were used. Lysozyme and fructose were incubated at 37 °C in the presence or absence of different concentrations of plant extracts up to 31 days. Standard glycation inhibitor aminoguanidine and other appropriate controls were included. A recently established sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE) method was used to detect the products of protein cross-linking in the incubation mixtures. High molecular weight protein products representing the dimer, trimer and tetramer of lysozyme were detected in the presence of fructose. Among the nine antidiabetic plants, seven showed glycation induced protein cross-linking inhibitory effects namely Ficus racemosa (FR) stem bark, Gymnema sylvestre (GS) leaves, Musa paradisiaca (MP) yam, Phyllanthus debilis (PD) whole plant, Phyllanthus emblica (PE) fruit, Pterocarpus marsupium (PM) latex and Tinospora cordifolia (TC) leaves. Inhibition observed with Coccinia grandis (CG) leaves and Strychnos potatorum (SP) seeds were much low. Leaves of Gymnema lactiferum (GL), the plant without known antidiabetic effects showed the lowest inhibition. All three spices namely Coriandrum sativum (CS) seeds, Cinnamomum zeylanicum (CZ) bark and Syzygium aromaticum (SA) flower buds showed cross-link inhibitory effects with higher effects in CS and SA. PD, PE, PM, CS and SA showed almost complete inhibition on the formation of cross-linking with 25 μg/ml extracts. Methanol extracts of PD, PE, PM, CS and SA have shown promising inhibitory effects on glycation induced protein cross-linking.

Time development in the early history of social networks: link stabilization, group dynamics, and segregation.

PubMed

Bruun, Jesper; Bearden, Ian G

2014-01-01

Studies of the time development of empirical networks usually investigate late stages where lasting connections have already stabilized. Empirical data on early network history are rare but needed for a better understanding of how social network topology develops in real life. Studying students who are beginning their studies at a university with no or few prior connections to each other offers a unique opportunity to investigate the formation and early development of link patterns and community structure in social networks. During a nine week introductory physics course, first year physics students were asked to identify those with whom they communicated about problem solving in physics during the preceding week. We use these students' self reports to produce time dependent student interaction networks. We investigate these networks to elucidate possible effects of different student attributes in early network formation. Changes in the weekly number of links show that while roughly half of all links change from week to week, students also reestablish a growing number of links as they progress through their first weeks of study. Using the Infomap community detection algorithm, we show that the networks exhibit community structure, and we use non-network student attributes, such as gender and end-of-course grade to characterize communities during their formation. Specifically, we develop a segregation measure and show that students structure themselves according to gender and pre-organized sections (in which students engage in problem solving and laboratory work), but not according to end-of-coure grade. Alluvial diagrams of consecutive weeks' communities show that while student movement between groups are erratic in the beginning of their studies, they stabilize somewhat towards the end of the course. Taken together, the analyses imply that student interaction networks stabilize quickly and that students establish collaborations based on who is immediately available to them and on observable personal characteristics.

Testosterone and sexual desire in healthy women and men.

PubMed

van Anders, Sari M

2012-12-01

Sexual desire is typically higher in men than in women, with testosterone (T) thought to account for this difference as well as within-sex variation in desire in both women and men. However, few studies have incorporated both hormonal and social or psychological factors in studies of sexual desire. The present study addressed how three psychological domains (sexual-relational, stress-mood, body-embodiment) were related to links between T and sexual desire in healthy adults and whether dyadic and solitary desire showed associations with T. Participants (n = 196) were recruited as part of the Partnering, Physiology, and Health study, which had 105 men and 91 women who completed questionnaires and provided saliva for cortisol and T assays. T was positively linked to solitary desire in women, with masturbation frequency influencing this link. In contrast, T was negatively correlated with dyadic desire in women, but only when cortisol and perceived social stress were controlled. Replicating past findings, no significant correlations between T and desire in men were apparent, but these analyses showed that the null association remained even when psychological and confound variables were controlled. Men showed higher desire than women, but masturbation frequency rather than T influenced this difference. Results were discussed in terms of challenges to assumptions of clear links between T and desire, gendered approaches to T, and the unitarity of desire.

Study of the effect of mixing approach on cross-linking efficiency of hyaluronic acid-based hydrogel cross-linked with 1,4-butanediol diglycidyl ether.

PubMed

Al-Sibani, Mohammed; Al-Harrasi, Ahmed; Neubert, Reinhard H H

2016-08-25

Regardless of various strategies reported for cross-linking hyaluronic acid (HA) with 1,4-butanediol diglycidyl ether (BDDE), seeking new strategies that enhance cross-linking efficiency with a low level of cross-linker is essential. In this work, we studied the influence of mixing approach on two cross-linked BDDE-HA hydrogels prepared by two different mixing approaches; the large-batch mixing approach in which the hydrogel quantities were all mixed as a single lump in one container (hydrogel 1), and the small-batches mixing approach in which the hydrogel quantities were divided into smaller batches, mixed separately at various HA/BDDE ratios then combined in one reaction mixture (hydrogel 2). The result showed that the cross-linking reaction was mixing process-dependent. Degradation tests proved that, in relation to hydrogel 1, hydrogel 2 was more stable, and exhibited a higher resistance towards hyaluronidase activity. The swelling ratio of hydrogel 1 was significantly higher than that of hydrogel 2 in distilled water; however, in phosphate buffer saline, both hydrogels showed no significant difference. SEM images demonstrated that hydrogel 2 composite showed a denser network structure and smaller pore-size than hydrogel 1. In comparison to native HA, the occurrence of chemical modification in the cross-linked hydrogels was confirmed by FTIR and NMR distinctive peaks. These peaks also provided evidence that hydrogel 2 exhibited a higher degree of modification than hydrogel 1. In conclusion, the small-batches mixing approach proved to be more effective than large-batch mixing in promoting HA-HA entanglement and increasing the probability of BDDE molecules for binding with HA chains. Copyright © 2016 Elsevier B.V. All rights reserved.

Linking of uniform random polygons in confined spaces

NASA Astrophysics Data System (ADS)

Arsuaga, J.; Blackstone, T.; Diao, Y.; Karadayi, E.; Saito, M.

2007-03-01

In this paper, we study the topological entanglement of uniform random polygons in a confined space. We derive the formula for the mean squared linking number of such polygons. For a fixed simple closed curve in the confined space, we rigorously show that the linking probability between this curve and a uniform random polygon of n vertices is at least 1-O\\big(\\frac{1}{\\sqrt{n}}\\big) . Our numerical study also indicates that the linking probability between two uniform random polygons (in a confined space), of m and n vertices respectively, is bounded below by 1-O\\big(\\frac{1}{\\sqrt{mn}}\\big) . In particular, the linking probability between two uniform random polygons, both of n vertices, is bounded below by 1-O\\big(\\frac{1}{n}\\big) .

Acquisition of choice in concurrent chains: Assessing the cumulative decision model.

PubMed

Grace, Randolph C

2016-05-01

Concurrent chains is widely used to study pigeons' choice between terminal links that can vary in delay, magnitude, or probability of reinforcement. We review research on the acquisition of choice in this procedure. Acquisition has been studied with a variety of research designs, and some studies have incorporated no-food trials to allow for timing and choice to be observed concurrently. Results show that: Choice can be acquired rapidly within sessions when terminal links change unpredictably; under steady-state conditions, acquisition depends on both initial- and terminal-link schedules; and initial-link responding is mediated by learning about the terminal-link stimulus-reinforcer relations. The cumulative decision model (CDM) proposed by Christensen and Grace (2010) and Grace and McLean (2006, 2015) provides a good description of within-session acquisition, and correctly predicts the effects of initial and terminal-link schedules in steady-state designs (Grace, 2002a). Questions for future research include how abrupt shifts in preference within individual sessions and temporal control of terminal-link responding can be modeled. Copyright © 2016 Elsevier B.V. All rights reserved.

Modifications of Saccharomyces pastorianus cell wall polysaccharides with brewing process.

PubMed

Bastos, Rita; Coelho, Elisabete; Coimbra, Manuel A

2015-06-25

The cell wall polysaccharides of brewers spent yeast Saccharomyces pastorianus (BSY) and the inoculum yeast (IY) were studied in order to understand the changes induced by the brewing process. The hot water and alkali extractions performed solubilized mainly mannoproteins, more branched for BSY than those of IY. Also, (31)P solid state NMR showed that the BSY mannoproteins were 3 times more phosphorylated. By electron microscopy it was observed that the final residues of alkali sequential extraction until 4M KOH preserved the yeast three-dimensional structure. The final residues, composed mainly by glucans (92%), showed that the BSY, when compared with IY, contained higher amount of (1→4)-linked Glc (43% for BSY and 16% for IY) and lower (1→3)-linked Glc (17% for BSY and 42% for IY). The enzymatic treatment of final residue showed that both BSY and IY had (α1→4)-linked Glc and (β1→4)-linked Glc, in a 2:1 ratio, showing that S. pastorianus increases their cellulose-like linkages with the brewing process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Investigation of hydrogel membranes containing combination of gentamicin and dexamethasone for ocular delivery

PubMed Central

Prabhu, Prabhakara; Dubey, Akhilesh; Parth, Vinod; Ghate, Vivek

2015-01-01

Background: Hydrogel is a cross-linked network of polymers. Water penetrates these network causing swelling and giving the hydrogel a soft and rubbery consistency and there by maintaining the integrity of the membrane. Due to the drawback of conventional therapy for ocular delivery, hydrogel membranes containing the combination of gentamicin (GT) sulfate and dexamethasone (DX) were formulated for the treatment of conjunctivitis. The objective of this study was to formulate and evaluate the hydrogel membranes containing the combination of GT and DX for the treatment of conjunctivitis. Materials and Methods: In the present investigation, hydrogel membranes were prepared by using polymers such as gelatin, polyvinyl alcohol, and chitosan, which were cross-linked using physical/chemical methods. Results: The cross-linking of the membranes was confirmed by Fourier transform infra-red studies. The pH of the membranes ranged from 7.19 to 7.45 and drug content ranged from 69.82% to 89.19%. The hydrogels showed a considerably good swelling ratio ranging from 22.5% to 365.56%. The in vitro drug release study showed that there was a slow and sustained release of the drug from the membranes which were sufficiently cross-linked and followed zero order release. In vivo studies showed that the severity of conjunctivitis was remarkably lowered at day 3 with hydrogel membrane compared to marketed eye drops. Results of unpaired t-test of significance between two groups indicated that the hydrogel membrane showed a better response in the treatment of conjunctivitis compared to the marketed products. Stability studies proved that the formulations could be stable when stored at room temperature. Conclusion: Results of the study indicated that it is possible to develop a safe and physiologically effective hydrogels which are patient compliant. PMID:26682192

Allelic variation of the FRMD7 gene in congenital idiopathic nystagmus.

PubMed

Self, James E; Shawkat, Fatima; Malpas, Crispin T; Thomas, N Simon; Harris, Christopher M; Hodgkins, Peter R; Chen, Xiaoli; Trump, Dorothy; Lotery, Andrew J

2007-09-01

To perform a genotype-phenotype correlation study in an X-linked congenital idiopathic nystagmus pedigree (pedigree 1) and to assess the allelic variance of the FRMD7 gene in congenital idiopathic nystagmus. Subjects from pedigree 1 underwent detailed clinical examination including nystagmology. Screening of FRMD7 was undertaken in pedigree 1 and in 37 other congenital idiopathic nystagmus probands and controls. Direct sequencing confirmed sequence changes. X-inactivation studies were performed in pedigree 1. The nystagmus phenotype was extremely variable in pedigree 1. We identified 2 FRMD7 mutations. However, 80% of X-linked families and 96% of simplex cases showed no mutations. X-inactivation studies demonstrated no clear causal link between skewing and variable penetrance. We confirm profound phenotypic variation in X-linked congenital idiopathic nystagmus pedigrees. We demonstrate that other congenital nystagmus genes exist besides FRMD7. We show that the role of X inactivation in variable penetrance is unclear in congenital idiopathic nystagmus. Clinical Relevance We demonstrate that phenotypic variation of nystagmus occurs in families with FRMD7 mutations. While FRMD7 mutations may be found in some cases of X-linked congenital idiopathic nystagmus, the diagnostic yield is low. X-inactivation assays are unhelpful as a test for carrier status for this disease.

Rheological Behavior, Granule Size Distribution and Differential Scanning Calorimetry of Cross-Linked Banana (Musa paradisiaca) Starch.

NASA Astrophysics Data System (ADS)

Núñez-Santiago, María C.; Maristany-Cáceres, Amira J.; Suárez, Francisco J. García; Bello-Pérez, Arturo

2008-07-01

Rheological behavior at 60 °C, granule size distribution and Differential Scanning Calorimetry (DSC) tests were employed to study the effect of diverse reaction conditions: adipic acid concentration, pH and temperature during cross-linking of banana (Musa paradisiaca) starch. These properties were determined in native banana starch pastes for the purpose of comparison. Rheological behavior from pastes of cross-linked starch at 60 °C did not show hysteresis, probably due the cross-linkage of starch that avoided disruption of granules, elsewhere, native starch showed hysteresis in a thixotropic loop. All pastes exhibited non-Newtonian shear thinning behavior. In all cases, size distribution showed a decrease in the median diameter in cross-linked starches. This condition produces a decrease in swelling capacity of cross-linked starch. The median diameter decreased with an increase of acid adipic concentration; however, an increase of pH and Temperature produced an increase in this variable. Finally, an increase in gelatinization temperature and entalphy (ΔH) were observed as an effect of cross-linkage. An increase in acid adipic concentration produced an increase in Tonset and a decrease in ΔH. pH and temperature. The cross-linked of banana starch produced granules more resistant during the pasting procedure.

Delineating the contribution of long-term associations to immediate recall.

PubMed

Saint-Aubin, Jean; Guérard, Katherine; Chamberland, Cindy; Malenfant, Amélie

2014-01-01

In the present study we examined the contribution of semantic associative links to short-term recall performance by using the separation effect first introduced in free recall studies (Glanzer, 1969). Pairs of associated words were inserted in the to-be-remembered lists. In two experiments associated words were better recalled than non-associated words, and were better recalled when they were adjacent in the list than when they were separated by one non-associated item. In addition results showed that forward associative links among pair members were as beneficial to immediate serial recall as backward associative links. Finally the benefit of associative links among pair members was observed with both forward and backward recall.

Risk markers for disappearance of pediatric Web resources

PubMed Central

Hernández-Borges, Angel A.; Jiménez-Sosa, Alejandro; Torres-Álvarez de Arcaya, Maria L.; Macías-Cervi, Pablo; Gaspar-Guardado, Maria A.; Ruíz-Rabaza, Ana

2005-01-01

Objectives: The authors sought to find out whether certain Webometric indexes of a sample of pediatric Web resources, and some tests based on them, could be helpful predictors of their disappearance. Methods: The authors performed a retrospective study of a sample of 363 pediatric Websites and pages they had followed for 4 years. Main measurements included: number of resources that disappeared, number of inbound links and their annual increment, average daily visits to the resources in the sample, sample compliance with the quality criteria of 3 international organizations, and online time of the Web resources. Results: On average, 11% of the sample disappeared annually. However, 13% of these were available again at the end of follow up. Disappearing and surviving Websites did not show differences in the variables studied. However, surviving Web pages had a higher number of inbound links and higher annual increment in inbound links. Similarly, Web pages that survived showed higher compliance with recognized sets of quality criteria than those that disappeared. A subset of 14 quality criteria whose compliance accounted for 90% of the probability of online permanence was identified. Finally, a progressive increment of inbound links was found to be a marker of good prognosis, showing high specificity and positive predictive value (88% and 94%, respectively). Conclusions: The number of inbound links and annual increment of inbound links could be useful markers of the permanence probability for pediatric Web pages. Strategies that assure the Web editors' awareness of their Web resources' popularity could stimulate them to improve the quality of their Websites. PMID:16059427

Links between marital and parent-child interactions: moderating role of husband-to-wife aggression.

PubMed

Margolin, Gayla; Gordis, Elana B; Oliver, Pamella H

2004-01-01

The present study examined how marital conflict may compromise parenting by identifying interdependencies across marital and parent-child subsystems in a sample of 86 two-parent families with a child aged 9-13. The study used direct observation of three family discussions to examine interdependencies across family subsystems. The study also assessed whether a history of husband-to-wife aggression strengthened interdependencies. Overall, families with husband-to-wife aggression showed a negative tone that pervaded throughout the family. Consistent with theories about physically aggressive men tending to withdraw from conflict, fathers who had engaged in husband-to-wife aggression showed an association between marital hostilities and lower levels of empathy toward their children. Consistent with stress theories, women who had been exposed to husband-to-wife aggression showed a link between marital hostilities and negative affect when interacting with their children. These findings illustrate how a history of exposure to marital aggression can create a family environment of multiple risks for children. For children in families with prior marital aggression, ongoing marital hostilities can be linked to the additional risk of erosions in parental support.

Lysyl hydroxylase 2 induces a collagen cross-link switch in tumor stroma

PubMed Central

Chen, Yulong; Terajima, Masahiko; Yang, Yanan; Sun, Li; Ahn, Young-Ho; Pankova, Daniela; Puperi, Daniel S.; Watanabe, Takeshi; Kim, Min P.; Blackmon, Shanda H.; Rodriguez, Jaime; Liu, Hui; Behrens, Carmen; Wistuba, Ignacio I.; Minelli, Rosalba; Scott, Kenneth L.; Sanchez-Adams, Johannah; Guilak, Farshid; Pati, Debananda; Thilaganathan, Nishan; Burns, Alan R.; Creighton, Chad J.; Martinez, Elisabeth D.; Zal, Tomasz; Grande-Allen, K. Jane; Yamauchi, Mitsuo; Kurie, Jonathan M.

2015-01-01

Epithelial tumor metastasis is preceded by an accumulation of collagen cross-links that heighten stromal stiffness and stimulate the invasive properties of tumor cells. However, the biochemical nature of collagen cross-links in cancer is still unclear. Here, we postulated that epithelial tumorigenesis is accompanied by changes in the biochemical type of collagen cross-links. Utilizing resected human lung cancer tissues and a p21CIP1/WAF1-deficient, K-rasG12D-expressing murine metastatic lung cancer model, we showed that, relative to normal lung tissues, tumor stroma contains higher levels of hydroxylysine aldehyde–derived collagen cross-links (HLCCs) and lower levels of lysine aldehyde–derived cross-links (LCCs), which are the predominant types of collagen cross-links in skeletal tissues and soft tissues, respectively. Gain- and loss-of-function studies in tumor cells showed that lysyl hydroxylase 2 (LH2), which hydroxylates telopeptidyl lysine residues on collagen, shifted the tumor stroma toward a high-HLCC, low-LCC state, increased tumor stiffness, and enhanced tumor cell invasion and metastasis. Together, our data indicate that LH2 enhances the metastatic properties of tumor cells and functions as a regulatory switch that controls the relative abundance of biochemically distinct types of collagen cross-links in the tumor stroma. PMID:25664850

Effect of carbon nanotube dispersion on glass transition in cross-linked epoxy-carbon nanotube nanocomposites: role of interfacial interactions.

PubMed

Khare, Ketan S; Khare, Rajesh

2013-06-20

We have used atomistic molecular simulations to study the effect of nanofiller dispersion on the glass transition behavior of cross-linked epoxy-carbon nanotube (CNT) nanocomposites. Specific chemical interactions at the interface of CNTs and cross-linked epoxy create an interphase region, whose impact on the properties of their nanocomposites increases with an increasing extent of dispersion. To investigate this aspect, we have compared the volumetric, structural, and dynamical properties of three systems: neat cross-linked epoxy, cross-linked epoxy nanocomposite containing dispersed CNTs, and cross-linked epoxy nanocomposite containing aggregated CNTs. We find that the nanocomposite containing dispersed CNTs shows a depression in the glass transition temperature (Tg) by ~66 K as compared to the neat cross-linked epoxy, whereas such a large depression is absent in the nanocomposite containing aggregated CNTs. Our results suggest that the poor interfacial interactions between the CNTs and the cross-linked epoxy matrix lead to a more compressible interphase region between the CNTs and the bulk matrix. An analysis of the resulting dynamic heterogeneity shows that the probability of percolation of immobile domains becomes unity near the Tg calculated from volumetric properties. Our observations also lend support to the conceptual analogy between polymer nanocomposites and the nanoconfinement of polymer thin films.

Glycerogelatin-based ocular inserts of aceclofenac: physicochemical, drug release studies and efficacy against prostaglandin E₂-induced ocular inflammation.

PubMed

Mathurm, Manish; Gilhotra, Ritu Mehra

2011-01-01

An attempt has been made in the present study to formulate soluble ocular inserts of aceclofenac to facilitate the bioavailability of the drug into the eye, as no eye drop solution could be formulated. Glycero-gelatin ocular inserts/films were prepared and physicochemical parameters and drug release profiles of glycerol-gelatin films of aceclofenac were compared with surface cross-linked films of similar compositions. Ocular irritation of the developed formulation was also checked by HET-CAM test and efficacy of the developed formulation against prostaglandin-induced ocular inflammation in rabbit eye was determined. The non-cross-linked films showed poor mechanical, physicochemical properties, and very little potential of sustaining drug release, however cross-linking the films enhanced tensile strength by 70%, but elasticity decreased by 95%. The cross-linked ocular inserts showed less swelling than non-cross-linked. Formulation AF8 (20% gelatin and 70% glycerin, treated by cross-linker for 1 h) demonstrated the longest drug release for 24 h. As per the kinetic models all films showed a constant drug release with Higuchi diffusion mechanism. Formulation was found to be practically non-irritant. The optimized formulation was tested and compared with eye drops of aceclofenac for anti-inflammatory activity in rabbits against PGE₂-induced inflammation. In vivo studies with developed formulation indicated a significant inhibition of PGE₂-induced PMN migration as compared to eye drops. In conclusion, ocular inserts of aceclofenac was found promising as it achieved sustained drug release and better pharmacodynamic activity.

Household Chaos--Links with Parenting and Child Behaviour

ERIC Educational Resources Information Center

Coldwell, Joanne; Pike, Alison; Dunn, Judy

2006-01-01

Background: The study aimed to confirm previous findings showing links between household chaos and parenting in addition to examining whether household chaos was predictive of children's behaviour over and above parenting. In addition, we investigated whether household chaos acts as a moderator between parenting and children's behaviour. Method:…

Influence of different crosslinking systems on the mechanical and morphological properties of thermoplastic vulcanizates

NASA Astrophysics Data System (ADS)

Patermann, Simone; Altstädt, Volker

2015-05-01

Thermoplastic vulcanizates (TPVs) combine the elastic properties of thermoset cross-linked rubbers with the melt processability of thermoplastics. The most representative examples of this class are the TPVs based on polypropylene (PP) and ethylene-propylene-diene terpolymer rubber (EPDM). The PP/EPDM blends were produced by dynamic vulcanization in a continuous extrusion process. The influence of different crosslinking systems was studied with regard to cross-link density, compression set, tensile strength/elongation at break and morphology. With increasing peroxide concentration, the cross-link density increases, leading to a reduction of the compression set by 50 %. The same improvement is only reachable with twice the concentration of phenolic resin. Only the peroxide cross-linked blends show smaller dispersed EPDM particles with increasing peroxide concentration. With a peroxide concentration between 0.2 and 0.5 wt. %, a maximum in tensile strength and elongation at break was found. For the phenolic resin cross-linked blends, the tensile strength stays almost constant with increasing phenolic resin concentration and the elongation at break shows best results at 0.5 wt. % phenolic resin. Compared to batch processes, the results show different values, but comparable trends.

Effect of Cross-Linking on Free Volume Properties of PEG Based Thiol-Ene Networks

NASA Astrophysics Data System (ADS)

Ramakrishnan, Ramesh; Vasagar, Vivek; Nazarenko, Sergei

According to the Fox and Loshaek theory, in elastomeric networks, free volume decreases linearly with the cross-link density increase. The aim of this study is to show whether the poly(ethylene glycol) (PEG) based multicomponent thiol-ene elastomeric networks demonstrate this model behavior? Networks with a broad cross-link density range were prepared by changing the ratio of the trithiol crosslinker to PEG dithiol and then UV cured with PEG diene while maintaining 1:1 thiol:ene stoichiometry. Pressure-volume-temperature (PVT) data of the networks was generated from the high pressure dilatometry experiments which was fit using the Simha-Somcynsky Equation-of-State analysis to obtain the fractional free volume of the networks. Using Positron Annihilation Lifetime Spectroscopy (PALS) analysis, the average free volume hole size of the networks was also quantified. The fractional free volume and the average free volume hole size showed a linear change with the cross-link density confirming that the Fox and Loshaek theory can be applied to this multicomponent system. Gas diffusivities of the networks showed a good correlation with free volume. A free volume based model was developed to describe the gas diffusivity trends as a function of cross-link density.

Fabrication of chemically cross-linked porous gelatin matrices.

PubMed

Bozzini, Sabrina; Petrini, Paola; Altomare, Lina; Tanzi, Maria Cristina

2009-01-01

The aim of this study was to chemically cross-link gelatin, by reacting its free amino groups with an aliphatic diisocyanate. To produce hydrogels with controllable properties, the number of reacting amino groups was carefully determined. Porosity was introduced into the gelatin-based hydrogels through the lyophilization process. Porous and non-porous matrices were characterized with respect to their chemical structure, morphology, water uptake and mechanical properties. The physical, chemical and mechanical properties of the porous matrices are related to the extent of their cross-linking, showing that they can be controlled by varying the reaction parameters. Water uptake values (24 hours) vary between 160% and 200% as the degree of cross-linking increases. The flexibility of the samples also decreases by changing the extent of cross-linking. Young's modulus shows values between 0.188 KPa, for the highest degree, and 0.142 KPa for the lowest degree. The matrices are potential candidates for use as tissue-engineering scaffolds by modulating their physical chemical properties according to the specific application.

I Can Read It in Your Eyes: What Eye Movements Tell Us about Visuo-Attentional Processes in Developmental Dyslexia

ERIC Educational Resources Information Center

Bellocchi, Stephanie; Muneaux, Mathilde; Bastien-Toniazzo, Mireille; Ducrot, Stephanie

2013-01-01

Most studies today agree about the link between visual-attention and oculomotor control during reading: attention seems to affect saccadic programming, that is, the position where the eyes land in a word. Moreover, recent studies show that visuo-attentional processes are strictly linked to normal and impaired reading. In particular, a large body…

Renewable energy and characteristics of the Earth

NASA Astrophysics Data System (ADS)

Léger, Valérie

2016-04-01

During studying sustainable development, my sixth-form pupils have to devise and carry out experiments to show connection between some characteristics of the Earth and renewable energy. Thus, helping by a list of equipment, they can show, using simples' experiments, causal link. For example, they show that the layout in latitude of solar energy received on the ground, creates ocean and atmospheric currents. These currents are useful to product renewable energy. These researches allow me to show them new jobs link with renewable energy and sustainable development on the Earth. They can have more information thanks to other teachers working on the professional training centre including my secondary school.

The vulnerability of the global container shipping network to targeted link disruption

NASA Astrophysics Data System (ADS)

Viljoen, Nadia M.; Joubert, Johan W.

2016-11-01

Using complex network theory to describe the relational geography of maritime networks has provided great insights regarding their hierarchy and evolution over the past two decades. Unlike applications in other transport fields, notably air transport, complex network theory has had limited application in studying the vulnerability of maritime networks. This study uses targeted link disruption to investigate the strategy specific vulnerability of the network. Although nodal infrastructure such as ports can render a network vulnerable as a result of labour strikes, trade embargoes or natural disasters, it is the shipping lines connecting the ports that are more probably disrupted, either from within the industry, or outside. In this paper, we apply and evaluate two link-based disruption strategies on the global container shipping network, one based on link betweenness, and the other on link salience, to emulate the impact of large-scale service reconfiguration affecting priority links. The results show that the network is by and large robust to such reconfiguration. Meanwhile the flexibility of the network is reduced by both strategies, but to a greater degree by betweenness, resulting in a reduction of transshipment and dynamic rerouting potential amongst the busiest port regions. The results further show that the salience strategy is highly effective in reducing the commonality of shortest path sets, thereby diminishing opportunities for freight consolidation and scale economies.

Investigation of different cross-linking approaches on 3D gelatin scaffolds for tissue engineering application: A comparative analysis.

PubMed

Shankar, K Gopal; Gostynska, Natalia; Montesi, Monica; Panseri, Silvia; Sprio, Simone; Kon, Elizaveta; Marcacci, Maurilio; Tampieri, Anna; Sandri, Monica

2017-02-01

The present study aims to investigate the physical-chemical and biological features exhibited by porous scaffolds for regeneration of cartilaginous tissues obtained through stabilization of 3D gelatin hydrogels by physical (DHT), chemical (BDDGE) and natural (Genipin) cross-linking approaches. The study aimed at comparatively assessing the porous microstructure and the long-term resistance of the scaffolds upon degradation in wet physiological conditions (37°C, pH=7.4). The degree of cross-linking increases as function of incorporation of cross-linkers which was maximum up to 73% for BDDGE. The infrared spectroscopy and thermal analysis confirmed the gelatin structure was preserved during the cross-linking treatments. Mechanical properties of the scaffolds were analysed by static and dynamic compression test, which showed different viscoelastic behaviour upon various cross-linking strategies. The biological performance of the scaffolds investigated using human chondrocytes showed good cell adhesion, viability and proliferation, as well as extensive 3D scaffold colonization. Besides, the analysis of gene expression related to the formation of new chondral tissue reported increasing ability with time in the formation of new extra-cellular matrix. In conclusion, out of three different cross-linking methods, the gelatin scaffolds subjected to dehydrothermal treatment (DHT) represented to be the most favourable 3D scaffold for cartilage regeneration. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of nonwoven fabrics consisting of gelatin nanofibers cross-linked by glutaraldehyde or N-acetyl-d-glucosamine by aqueous method.

PubMed

Furuike, Tetsuya; Chaochai, Thitirat; Okubo, Tsubasa; Mori, Takahiro; Tamura, Hiroshi

2016-12-01

Since gelatin (Gel) undergoes a sol-gel transition, a novel dry-spinning procedure for Gel was used. Here, nonwoven fabrics of Gel were electrospun by applying the principles of dry spinning. The diameter of the fibers and the viscosity and flow rate of the solution were directly dependent on the concentration of Gel. Nonwoven fabrics spun with a 25% (w/w) Gel concentration only exhibited a nanoscale fiber diameter. In order to improve the properties of the nonwoven fabrics, they were cross-linked with glutaraldehyde (GTA) vapor after spinning or by the addition of N-acetyl-d-glucosamine (GlcNAc) to the Gel solution prior to spinning followed by heating these fibers. The developed nonwoven fibers were characterized using SEM, rheometry, FTIR, TGA, and mechanical tensile testing. The nonwoven fabrics cross-linked by the GTA vapor exhibited improved mechanical properties compared to those without cross-linking or with GlcNAc cross-linking. The swelling and water uptake ability resulted in no morphological changes in the fibers with GTA cross-linking. The TGA thermogram confirmed no phase change in the composite structure. Further, in vitro cytocompatibility studies using human mesenchymal stem cells showed the compatible nature of the developed nonwoven fibers. Our studies showed that these nonwoven fibers could be useful in medical care. Copyright © 2016 Elsevier B.V. All rights reserved.

Pre-configured polyhedron based protection against multi-link failures in optical mesh networks.

PubMed

Huang, Shanguo; Guo, Bingli; Li, Xin; Zhang, Jie; Zhao, Yongli; Gu, Wanyi

2014-02-10

This paper focuses on random multi-link failures protection in optical mesh networks, instead of single, the dual or sequential failures of previous studies. Spare resource efficiency and failure robustness are major concerns in link protection strategy designing and a k-regular and k-edge connected structure is proved to be one of the optimal solutions for link protection network. Based on this, a novel pre-configured polyhedron based protection structure is proposed, and it could provide protection for both simultaneous and sequential random link failures with improved spare resource efficiency. Its performance is evaluated in terms of spare resource consumption, recovery rate and average recovery path length, as well as compared with ring based and subgraph protection under probabilistic link failure scenarios. Results show the proposed novel link protection approach has better performance than previous works.

Synthesis, Characterization, and Antibacterial Activity of Cross-Linked Chitosan-Glutaraldehyde

PubMed Central

Li, Bin; Shan, Chang-Lin; Zhou, Qing; Fang, Yuan; Wang, Yang-Li; Xu, Fei; Han, Li-Rong; Ibrahim, Muhammad; Guo, Long-Biao; Xie, Guan-Lin; Sun, Guo-Chang

2013-01-01

This present study deals with synthesis, characterization and antibacterial activity of cross-linked chitosan-glutaraldehyde. Results from this study indicated that cross-linked chitosan-glutaraldehyde markedly inhibited the growth of antibiotic-resistant Burkholderia cepacia complex regardless of bacterial species and incubation time while bacterial growth was unaffected by solid chitosan. Furthermore, high temperature treated cross-linked chitosan-glutaraldehyde showed strong antibacterial activity against the selected strain 0901 although the inhibitory effects varied with different temperatures. In addition, physical-chemical and structural characterization revealed that the cross-linking of chitosan with glutaraldehyde resulted in a rougher surface morphology, a characteristic Fourier transform infrared (FTIR) band at 1559 cm−1, a specific X-ray diffraction peak centered at 2θ = 15°, a lower contents of carbon, hydrogen and nitrogen, and a higher stability of glucose units compared to chitosan based on scanning electron microscopic observation, FTIR spectra, X-ray diffraction pattern, as well as elemental and thermo gravimetric analysis. Overall, this study indicated that cross-linked chitosan-glutaraldehyde is promising to be developed as a new antibacterial drug. PMID:23670533

Chromatin structure and methylation of rat rRNA genes studied by formaldehyde fixation and psoralen cross-linking.

PubMed Central

Stancheva, I; Lucchini, R; Koller, T; Sogo, J M

1997-01-01

By using formaldehyde cross-linking of histones to DNA and gel retardation assays we show that formaldehyde fixation, similar to previously established psoralen photocross-linking, discriminates between nucleosome- packed (inactive) and nucleosome-free (active) fractions of ribosomal RNA genes. By both cross-linking techniques we were able to purify fragments from agarose gels, corresponding to coding, enhancer and promoter sequences of rRNA genes, which were further investigated with respect to DNA methylation. This approach allows us to analyse independently and in detail methylation patterns of active and inactive rRNA gene copies by the combination of Hpa II and Msp I restriction enzymes. We found CpG methylation mainly present in enhancer and promoter regions of inactive rRNA gene copies. The methylation of one single Hpa II site, located in the promoter region, showed particularly strong correlation with the transcriptional activity. PMID:9108154

A Causality Analysis of the Link between Higher Education and Economic Development.

ERIC Educational Resources Information Center

De Meulemeester, Jean-Luc; Rochat, Denis

1995-01-01

Summarizes a study exploring the relationship between higher education and economic development, using cointegration and Granger-causality tests. Results show a significant causality from higher education efforts in Sweden, United Kingdom, Japan, and France. However, a similar causality link has not been found for Italy or Australia. (68…

High-Fat Diet Linked to Prostate Cancer Metastasis

Cancer.gov

A new study in mice has revealed a molecular link between a high-fat diet and the growth and spread of prostate cancer. As this Cancer Currents post explains, researchers also showed that an anti-obesity drug that targets a protein that controls fat synthesis could potentially be used to treat metastatic prostate cance

Introduction: Links between Social Interaction and Executive Function

ERIC Educational Resources Information Center

Lewis, Charlie; Carpendale, Jeremy I. M.

2009-01-01

The term executive function is used increasingly within developmental psychology and is often taken to refer to unfolding brain processes. We trace the origins of research on executive function to show that the link with social interaction has a long history. We suggest that a recent frenzy of research exploring methods for studying individual…

A piloted simulation study of data link ATC message exchange

NASA Technical Reports Server (NTRS)

Waller, Marvin C.; Lohr, Gary W.

1989-01-01

Data link Air Traffic Control (ATC) and Air Traffic Service (ATS) message and data exchange offers the potential benefits of increased flight safety and efficiency by reducing communication errors and allowing more information to be transferred between aircraft and ground facilities. Digital communication also presents an opportunity to relieve the overloading of ATC radio frequencies which hampers message exchange during peak traffic hours in many busy terminal areas. A piloted simulation study to develop pilot factor guidelines and assess potential flight crew benefits and liabilities from using data link ATC message exchange was completed. The data link ATC message exchange concept, implemented on an existing navigation computer Control Display Unit (CDU) required maintaining a voice radio telephone link with an appropriate ATC facility. Flight crew comments, scanning behavior, and measurements of time spent in ATC communication activities for data link ATC message exchange were compared to similar measures for simulated conventional voice radio operations. The results show crew preference for the quieter flight deck environment and a perception of lower communication workload.

Trust from the past: Bayesian Personalized Ranking based Link Prediction in Knowledge Graphs

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

Zhang, Baichuan; Choudhury, Sutanay; Al-Hasan, Mohammad

2016-02-01

Estimating the confidence for a link is a critical task for Knowledge Graph construction. Link prediction, or predicting the likelihood of a link in a knowledge graph based on prior state is a key research direction within this area. We propose a Latent Feature Embedding based link recommendation model for prediction task and utilize Bayesian Personalized Ranking based optimization technique for learning models for each predicate. Experimental results on large-scale knowledge bases such as YAGO2 show that our approach achieves substantially higher performance than several state-of-art approaches. Furthermore, we also study the performance of the link prediction algorithm in termsmore » of topological properties of the Knowledge Graph and present a linear regression model to reason about its expected level of accuracy.« less

Link importance incorporated failure probability measuring solution for multicast light-trees in elastic optical networks

NASA Astrophysics Data System (ADS)

Li, Xin; Zhang, Lu; Tang, Ying; Huang, Shanguo

2018-03-01

The light-tree-based optical multicasting (LT-OM) scheme provides a spectrum- and energy-efficient method to accommodate emerging multicast services. Some studies focus on the survivability technologies for LTs against a fixed number of link failures, such as single-link failure. However, a few studies involve failure probability constraints when building LTs. It is worth noting that each link of an LT plays different important roles under failure scenarios. When calculating the failure probability of an LT, the importance of its every link should be considered. We design a link importance incorporated failure probability measuring solution (LIFPMS) for multicast LTs under independent failure model and shared risk link group failure model. Based on the LIFPMS, we put forward the minimum failure probability (MFP) problem for the LT-OM scheme. Heuristic approaches are developed to address the MFP problem in elastic optical networks. Numerical results show that the LIFPMS provides an accurate metric for calculating the failure probability of multicast LTs and enhances the reliability of the LT-OM scheme while accommodating multicast services.

Adsorption of hexavalent chromium on modified corn stalk using different cross-linking agents

NASA Astrophysics Data System (ADS)

Chen, Suhong; Zhu, Yi; Han, Zhijun; Feng, Gao; Jia, Yuling; Fu, Kaifang; Yue, Qinyan

2017-12-01

In this study, four different types of adsorbents modified from corn stalk were synthesized after the reaction with epichlorohydrin, N,N-dimethylformamide, triethylamine and different cross-linking agents. The surface functional groups and thermal stability of modified corn stalk (MCSs) were characterized using FTIR and TG analysis, respectively. The feasibility of using MCSs to remove Cr(VI) were evaluated. Adsorption isotherms were determined and modeled with Langmuir, Freundlich and Temkin equations. The experimental results showed that MCS modified using diethylenetriamine (DETA) had the best modification effect, and the adsorption capacity of Cr(VI) reached as high as 227.27 mg/g at 323 K. Thermodynamic study showed that the Cr(VI) adsorption onto MCSs was endothermic processes. As a result, MCS by using DETA as cross-linking agent has good potential for the removal of Cr(VI) from aqueous solutions.

A Study into the Collision-induced Dissociation (CID) Behavior of Cross-Linked Peptides*

PubMed Central

Giese, Sven H.; Fischer, Lutz; Rappsilber, Juri

2016-01-01

Cross-linking/mass spectrometry resolves protein–protein interactions or protein folds by help of distance constraints. Cross-linkers with specific properties such as isotope-labeled or collision-induced dissociation (CID)-cleavable cross-linkers are in frequent use to simplify the identification of cross-linked peptides. Here, we analyzed the mass spectrometric behavior of 910 unique cross-linked peptides in high-resolution MS1 and MS2 from published data and validate the observation by a ninefold larger set from currently unpublished data to explore if detailed understanding of their fragmentation behavior would allow computational delivery of information that otherwise would be obtained via isotope labels or CID cleavage of cross-linkers. Isotope-labeled cross-linkers reveal cross-linked and linear fragments in fragmentation spectra. We show that fragment mass and charge alone provide this information, alleviating the need for isotope-labeling for this purpose. Isotope-labeled cross-linkers also indicate cross-linker-containing, albeit not specifically cross-linked, peptides in MS1. We observed that acquisition can be guided to better than twofold enrich cross-linked peptides with minimal losses based on peptide mass and charge alone. By help of CID-cleavable cross-linkers, individual spectra with only linear fragments can be recorded for each peptide in a cross-link. We show that cross-linked fragments of ordinary cross-linked peptides can be linearized computationally and that a simplified subspectrum can be extracted that is enriched in information on one of the two linked peptides. This allows identifying candidates for this peptide in a simplified database search as we propose in a search strategy here. We conclude that the specific behavior of cross-linked peptides in mass spectrometers can be exploited to relax the requirements on cross-linkers. PMID:26719564

Novel isolation of water-soluble polysaccharides from the fruiting bodies of Pleurotus ostreatus mushrooms.

PubMed

Palacios, Irene; García-Lafuente, Ana; Guillamón, Eva; Villares, Ana

2012-09-01

Novel water-soluble polysaccharides have been isolated from the fruiting bodies of the edible mushroom Pleurotus ostreatus. Three polysaccharide fractions were obtained by ethanol precipitation from cold water, hot water and hot aqueous NaOH extracts. The fractions were purified by size exclusion chromatography showing a unique carbohydrate occurring in each fraction: PC from the cold fraction, PH from the hot fraction and PB from the hot aqueous NaOH fraction. The analysis of the methylated alditol acetates and the NMR studies revealed that all the polysaccharides displayed a linear backbone. PC was formed by α-(1→3),(1→6)-linked galactopyranosyl residues whereas PH and PB consisted of glucose-linked units. PH was exclusively composed of glucopyranosyl units bound by α-(1→4) linkages whereas PB was a β-linked glucan showing (1→3) and (1→6) glycosidic bonds. The analysis of molecular arrangement by complexation with Congo red showed that only the β-linked polysaccharide (PB) displayed a triple helix conformation. Copyright © 2012 Elsevier Ltd. All rights reserved.

In vivo oxidation in remelted highly cross-linked retrievals.

PubMed

Currier, B H; Van Citters, D W; Currier, J H; Collier, J P

2010-10-20

Elimination of free radicals to prevent oxidation has played a major role in the development and product differentiation of the latest generation of highly cross-linked ultra-high molecular weight polyethylene bearing materials. In the current study, we (1) examined oxidation in a series of retrieved remelted highly cross-linked ultra-high molecular weight polyethylene bearings from a number of device manufacturers and (2) compared the retrieval results with findings for shelf-stored control specimens. The hypothesis was that radiation-cross-linked remelted ultra-high molecular weight polyethylene would maintain oxidative stability in vivo comparable with the stability during shelf storage and in published laboratory aging tests. Fifty remelted highly cross-linked ultra-high molecular weight polyethylene acetabular liners and nineteen remelted highly cross-linked ultra-high molecular weight polyethylene tibial inserts were received after retrieval from twenty-one surgeons from across the U.S. Thirty-two of the retrievals had been in vivo for two years or more. Each was measured for oxidation with use of Fourier transform infrared spectroscopy. A control series of remelted highly cross-linked ultra-high molecular weight polyethylene acetabular liners from three manufacturers was analyzed with electron paramagnetic resonance spectroscopy to measure free radical content and with Fourier transform infrared spectroscopy to measure oxidation initially and after eight to nine years of shelf storage in air. The never-implanted, shelf-aged controls had no measurable free-radical content initially or after eight to nine years of shelf storage. The never-implanted controls showed no increase in oxidation during shelf storage. Oxidation measurements showed measurable oxidation in 22% of the retrieved remelted highly cross-linked liners and inserts after an average of two years in vivo. Because never-implanted remelted highly cross-linked ultra-high molecular weight polyethylene materials had no measurable free-radical concentration and no increase in oxidation during shelf storage, these materials were expected to be oxidation-resistant in vivo. However, some remelted highly cross-linked ultra-high molecular weight polyethylene retrievals showed measurable oxidation after an average of more than two years in vivo. This apparent departure from widely expected behavior requires continued study of the process of in vivo oxidation of ultra-high molecular weight polyethylene materials.

Phase Diagrams of Three-Dimensional Anderson and Quantum Percolation Models Using Deep Three-Dimensional Convolutional Neural Network

NASA Astrophysics Data System (ADS)

Mano, Tomohiro; Ohtsuki, Tomi

2017-11-01

The three-dimensional Anderson model is a well-studied model of disordered electron systems that shows the delocalization-localization transition. As in our previous papers on two- and three-dimensional (2D, 3D) quantum phase transitions [J. Phys. Soc. Jpn. 85, 123706 (2016), 86, 044708 (2017)], we used an image recognition algorithm based on a multilayered convolutional neural network. However, in contrast to previous papers in which 2D image recognition was used, we applied 3D image recognition to analyze entire 3D wave functions. We show that a full phase diagram of the disorder-energy plane is obtained once the 3D convolutional neural network has been trained at the band center. We further demonstrate that the full phase diagram for 3D quantum bond and site percolations can be drawn by training the 3D Anderson model at the band center.

Folic acid-targeted disulfide-based cross-linking micelle for enhanced drug encapsulation stability and site-specific drug delivery against tumors

PubMed Central

Zhang, Yumin; Zhou, Junhui; Yang, Cuihong; Wang, Weiwei; Chu, Liping; Huang, Fan; Liu, Qiang; Deng, Liandong; Kong, Deling; Liu, Jianfeng; Liu, Jinjian

2016-01-01

Although the shortcomings of small molecular antitumor drugs were efficiently improved by being entrapped into nanosized vehicles, premature drug release and insufficient tumor targeting demand innovative approaches that boost the stability and tumor responsiveness of drug-loaded nanocarriers. Here, we show the use of the core cross-linking method to generate a micelle with enhanced drug encapsulation ability and sensitivity of drug release in tumor. This kind of micelle could increase curcumin (Cur) delivery to HeLa cells in vitro and improve tumor accumulation in vivo. We designed and synthesized the core cross-linked micelle (CCM) with polyethylene glycol and folic acid-polyethylene glycol as the hydrophilic units, pyridyldisulfide as the cross-linkable and hydrophobic unit, and disulfide bond as the cross-linker. CCM showed spherical shape with a diameter of 91.2 nm by the characterization of dynamic light scattering and transmission electron microscope. Attributed to the core cross-linking, drug-loaded CCM displayed higher Nile Red or Cur-encapsulated stability and better sensitivity to glutathione than noncross-linked micelle (NCM). Cellular uptake and in vitro antitumor studies proved the enhanced endocytosis and better cytotoxicity of CCM-Cur against HeLa cells, which had a high level of glutathione. Meanwhile, the folate receptor-mediated drug delivery (FA-CCM-Cur) further enhanced the endocytosis and cytotoxicity. Ex vivo imaging studies showed that CCM-Cur and FA-CCM-Cur possessed higher tumor accumulation until 24 hours after injection. Concretely, FA-CCM-Cur exhibited the highest tumor accumulation with 1.7-fold of noncross-linked micelle Cur and 2.8-fold of free Cur. By combining cross-linking of the core with active tumor targeting of FA, we demonstrated a new and effective way to design nanocarriers for enhanced drug encapsulation, smart tumor responsiveness, and elevated tumor accumulation. PMID:27051287

Intra-molecular cross-linking of acidic residues for protein structure studies.

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

Kruppa, Gary Hermann; Young, Malin M.; Novak, Petr

2005-03-01

Intra-molecular cross-linking has been suggested as a method of obtaining distance constraints that would be useful in developing structural models of proteins. Recent work published on intra-molecular cross-linking for protein structural studies has employed commercially available primary amine selective reagents that can cross-link lysine residues to other lysine residues or the amino terminus. Previous work using these cross-linkers has shown that for several proteins of known structure, the number of cross-links that can be obtained experimentally may be small compared to what would be expected from the known structure, due to the relative reactivity, distribution, and solvent accessibility of themore » lysines in the protein sequence. To overcome these limitations we have investigated the use of cross-linking reagents that can react with other reactive sidechains in proteins. We used 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) to activate the carboxylic acid containing residues, aspartic acid (D), glutamic acid (E), and the carboxy terminus (O), for cross-linking reactions. Once activated, the DEO sidechains can react to form 'zero-length' cross-links with nearby primary amine containing resides, lysines (K) and the amino terminus (X), via the formation of a new amide bond. We also show that the EDC-activated DEO sidechains can be cross-linked to each other using dihydrazides, two hydrazide moieties connected by an alkyl cross-linker ann of variable length. Using these reagents, we have found three new 'zero-length' cross-links in ubiquitin consistent with its known structure (M1-E16, M1-E18, and K63-E64). Using the dihydrazide cross-linkers, we have identified 2 new cross-links (D21-D32 and E24-D32) unambiguously. Using a library of dihydrazide cross-linkers with varying arm length, we have shown that there is a minimum arm length required for the DEO-DEO cross-links of 5.8 angstroms. These results show that additional structural information can be obtained by exploiting new cross-linker chemistry, increasing the probability that the protein target of choice will yield sufficient distance constraints to develop a structural model.« less

Synthesis and characterization of a novel hyaluronic acid hydrogel.

PubMed

Zhao, X

2006-01-01

Hyaluronic acid (hyaluronan, HA) has many medical applications as a biomaterial. To enhance its biostability, a novel hydrogel of cross-linked hyaluronic acid was prepared using a double cross-linking process, which involves building cross-linkages between hydroxyl group pairs and carboxyl group pairs. The present study explored a number of cross-linking processes in order to obtain different degrees of cross-linking, which were evaluated by the measurement of water absorption capacity as an index of the gel network density. To gain a better understanding of the stability of the gel, the chemical structure and particularly the rheological behaviour of the cross-linked HA, which included the influences of factors, such as degree of cross-linking, HA concentration and gel particle size, were investigated. The in vitro biostability against hyaluronidase and free radical degradation was tested to show that the cross-linked hydrogel had improved resistance to in vitro hyaluronidase and free radical degradation.

Enhanced correlation of received power-signal fluctuations in bidirectional optical links

NASA Astrophysics Data System (ADS)

Minet, Jean; Vorontsov, Mikhail A.; Polnau, Ernst; Dolfi, Daniel

2013-02-01

A study of the correlation between the power signals received at both ends of bidirectional free-space optical links is presented. By use of the quasi-optical approximation, we show that an ideal (theoretically 100%) power-signal correlation can be achieved in optical links with specially designed monostatic transceivers based on single-mode fiber collimators. The theoretical prediction of enhanced correlation is supported both by experiments conducted over a 7 km atmospheric path and wave optics numerical analysis of the corresponding bidirectional optical link. In the numerical simulations, we also compare correlation properties of received power signals for different atmospheric conditions and for optical links with monostatic and bistatic geometries based on single-mode fiber collimator and on power-in-the-bucket transceiver types. Applications of the observed phenomena for signal fading mitigation and turbulence-enhanced communication link security in free-space laser communication links are discussed.

Spreading of cooperative behaviour across interdependent groups

NASA Astrophysics Data System (ADS)

Jiang, Luo-Luo; Perc, Matjaž

2013-08-01

Recent empirical research has shown that links between groups reinforce individuals within groups to adopt cooperative behaviour. Moreover, links between networks may induce cascading failures, competitive percolation, or contribute to efficient transportation. Here we show that there in fact exists an intermediate fraction of links between groups that is optimal for the evolution of cooperation in the prisoner's dilemma game. We consider individual groups with regular, random, and scale-free topology, and study their different combinations to reveal that an intermediate interdependence optimally facilitates the spreading of cooperative behaviour between groups. Excessive between-group links simply unify the two groups and make them act as one, while too rare between-group links preclude a useful information flow between the two groups. Interestingly, we find that between-group links are more likely to connect two cooperators than in-group links, thus supporting the conclusion that they are of paramount importance.

High-speed optical feeder-link system using adaptive optics

NASA Astrophysics Data System (ADS)

Arimoto, Yoshinori; Hayano, Yutaka; Klaus, Werner

1997-05-01

We propose a satellite laser communication system between a ground station and a geostationary satellite, named high- speed optical feeder link system. It is based on the application of (a) high-speed optical devices, which have been developed for ground-based high-speed fiber-optic communications, and (b) the adaptive optics which compensates wavefront distortions due to atmospheric turbulences using a real time feedback control. A link budget study shows that a system with 10-Gbps bit-rate are available assuming the state-of-the-art device performance of the Er-doped fiber amplifier. We further discuss preliminary measurement results of the atmospheric turbulence at the telescope site in Tokyo, and present current study on the design of the key components for the feeder-link laser transceiver.

Carbamate-linked cationic lipids with different hydrocarbon chains for gene delivery.

PubMed

Shi, Jia; Yu, Shijun; Zhu, Jie; Zhi, Defu; Zhao, Yinan; Cui, Shaohui; Zhang, Shubiao

2016-05-01

A series of carbamate-linked cationic lipids containing saturated or unsaturated hydrocarbon chains and quaternary ammonium head were designed and synthesized. After recrystallization, carbamate-linked cationic lipids with high purity (over 95%) were obtained. The structures of these lipids were proved by IR spectrum, HR-ESI-MS, HPLC, (1)H NMR and (13)C NMR. The liposomes were prepared by using these cationic lipids and neutral lipid DOPE. Particle size and zeta-potential were studied to show that they were suitable for gene transfection. The DNA-bonding ability of C12:0, C14:0 and C18:1 cationic liposomes was much better than others. The results of transfection showed that hydrophobic chains of these lipids have great effects on their transfection activity. The lipids bearing C12:0, C14:0 saturated chains or C18:1 unsaturated chain showed relatively higher transfection efficiency and lower cytotoxicity. So these cationic lipids could be used as non-viral gene carriers for further studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Localization to Xq22 and clinical update of a family with X-linked recessive mental retardation with progression sensorineural deafness, progressive tapeto-retinal degeneration and dystonia

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

Tranebjaerg, L.; Schwartz, C.; Huggins, K.

1994-07-15

In a reinvestigation of a six-generation Norwegian family, originally reported with non-syndromic X-linked recessive deafness by Mohr and Mageroy, we have demonstrated several syndromic manifestations. The 10 clinically characterized affected males range in age from 14-61 years, and show progressive mental deterioration and visual disability. Ophthalmological and electrophysiological studies showed myopia, decreased visual acuity, combined cone-rod dystrophy as well as central areolar dystrophy by means of ERG. Brain CT-scans showed cortical and central atrophy without predilection to specific areas. Linkage analysis, using X-chromosomal RFLPs and CA-repeats, yielded a maximum LOD score of 4.37 with linkage to DXS17. DXS17 is localizedmore » to Xq22. One recombinant with COL4A5 (deficient in Alport syndrome) was observed. Results from the studies of this family will be important in reclassification of non-syndromic X-linked deafness since the family now represents syndromic deafness and XLMR with a specific phenotype.« less

Comparative Effects of Computer-Based Concept Maps, Refutational Texts, and Expository Texts on Science Learning

ERIC Educational Resources Information Center

Adesope, Olusola O.; Cavagnetto, Andy; Hunsu, Nathaniel J.; Anguiano, Carlos; Lloyd, Joshua

2017-01-01

This study used a between-subjects experimental design to examine the effects of three different computer-based instructional strategies (concept map, refutation text, and expository scientific text) on science learning. Concept maps are node-link diagrams that show concepts as nodes and relationships among the concepts as labeled links.…

Understanding the Authoritative Parenting-Early Adolescent Tobacco Use Link; The Mediating Role of Peer Tobacco Use.

ERIC Educational Resources Information Center

Adamczyk-Robinette, Stacey L.; Fletcher, Anne C.; Wright, Kristie

2002-01-01

Studied the link between authoritative parenting style and early adolescent tobacco use through the self-reports of 156 eighth graders and independent reports on tobacco use from their friends. Results show that high levels of authoritative parenting are associated with lower levels of tobacco use among target adolescents. (SLD)

Brief Measure of Student-Instructor Rapport Predicts Student Success in Online Courses

ERIC Educational Resources Information Center

Lammers, William J.; Gillaspy, J. Arthur, Jr.

2013-01-01

At all educational levels, researchers show a positive link between student-teacher rapport and student outcomes. However, few scales have been developed to measure rapport at the university level and no study has examined the link between student-instructor rapport and objective measures of student learning in online courses. We developed a…

Community of Communities: An Electronic Link to Integrating Cultural Diversity in Nursing Curriculum.

ERIC Educational Resources Information Center

Ryan, Marilyn; Ali, Nagia; Carlton, Kay Hodson

2002-01-01

The Community of Communities (COC) website contains information and case studies based on cultural assessment. Online nursing courses are linked to a cultural module in the COC. Evaluation results from 63 students showed that the COC increased awareness of the role of culture in health care and knowledge of international health practices.…

γ-PGA and MTGase improve the formation of ε-(γ-glutamyl) lysine cross-links within hairtail (Trichiurus haumela) surimi protein.

PubMed

Hu, Yaqin; Shao, Ying; Wu, Chunhua; Yuan, Chunhong; Ishimura, Gakushi; Liu, Wenjuan; Chen, Shiguo

2018-03-01

The present study investigated the mechanism of ε-(γ-glutamyl) lysine cross-links within hairtail (Trichiurus haumela) surimi protein via γ-polyglutamic acid (γ-PGA) and MTGase. The results indicated that the addition of MTGase and γ-PGA markedly improved the gelation properties of hairtail surimi protein, including its maximum breaking force and deformation, water holding capacity and gel strength. The maximum improvements were achieved by adding 0.5units MTGase/g meat paste in combination with 0.06% γ-PGA. SDS-PAGE showed that the band intensity of cross-linked proteins increased, whereas that of myosin heavy chain decreased after treatments. Further scanning electron microscopy (SEM) analysis showed the formation of a denser gel matrix, which was caused by much stronger and more inter- and intra-molecular cross-linking of proteins, via MTGase catalysing ε-(γ-glutamyl) lysine cross-links formed between lysine residues in the gel protein and glutamic residues in the hydrolytic γ-PGA. The results provide reliable guidance for the improvement of hairtail surimi protein gelation properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mining gene link information for survival pathway hunting.

PubMed

Jing, Gao-Jian; Zhang, Zirui; Wang, Hong-Qiang; Zheng, Hong-Mei

2015-08-01

This study proposes a gene link-based method for survival time-related pathway hunting. In this method, the authors incorporate gene link information to estimate how a pathway is associated with cancer patient's survival time. Specifically, a gene link-based Cox proportional hazard model (Link-Cox) is established, in which two linked genes are considered together to represent a link variable and the association of the link with survival time is assessed using Cox proportional hazard model. On the basis of the Link-Cox model, the authors formulate a new statistic for measuring the association of a pathway with survival time of cancer patients, referred to as pathway survival score (PSS), by summarising survival significance over all the gene links in the pathway, and devise a permutation test to test the significance of an observed PSS. To evaluate the proposed method, the authors applied it to simulation data and two publicly available real-world gene expression data sets. Extensive comparisons with previous methods show the effectiveness and efficiency of the proposed method for survival pathway hunting.

In Vivo Immune Responses of Cross-Linked Electrospun Tilapia Collagen Membrane.

PubMed

Hassanbhai, Ammar Mansoor; Lau, Chau Sang; Wen, Feng; Jayaraman, Praveena; Goh, Bee Tin; Yu, Na; Teoh, Swee-Hin

2017-10-01

Collagen has been used extensively in tissue engineering applications. However, the source of collagen has been primarily bovine and porcine. In view of the potential risk of zoonotic diseases and religious constraints associated with bovine and porcine collagen, fish collagen was examined as an alternative. The aim of this study is to use tilapia fish collagen to develop a cross-linked electrospun membrane to be used as a barrier membrane in guided bone regeneration. As there is limited data available on the cytotoxicity and immunogenicity of cross-linked tilapia collagen, in vitro and in vivo tests were performed to evaluate this in comparison to the commercially available Bio-Gide ® membrane. In this study, collagen was extracted and purified from tilapia skin and electrospun into a nanofibrous membrane. The resultant membrane was cross-linked to obtain a cross-linked electrospun tilapia collagen (CETC) membrane, which was characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), degradation studies, cytotoxicity studies, and cell proliferation studies. The membranes were also implanted subcutaneously in rats and the host immune responses were examined. The DSC data showed that cross-linking increased the denaturation temperature of tilapia collagen to 58.3°C ± 1.4°C. The in vitro tests showed that CETC exhibited no cytotoxicity toward murine fibroblast L929 cells, and culture of murine preosteoblast MC3T3-E1 cells demonstrated better proliferation on CETC as compared to Bio-Gide. When implanted in rats, CETC caused a higher production of interleukin IL-6 at early time points as compared to Bio-Gide, but there was no long-term inflammatory responses after the acute inflammation phase. This finding was supported with histology data, which clearly illustrated that CETC has a decreased inflammatory response comparable to the benchmark control group. In all, this study demonstrated the viability for the use of CETC as a tissue engineering scaffold and provides an insight on the in vivo immune responses toward xenogenic collagen scaffolds.

A historical study to understand students’ current difficulties about RMS values

NASA Astrophysics Data System (ADS)

Khantine-Langlois, Françoise; Munier, Valérie

2016-07-01

Several studies show that students experience more and more difficulties managing the measurements of electrical values in alternating current and that they have trouble making links between theory and practice. They find it difficult to give meaning to root mean square (RMS; or effective) values, which are not understood as average values and are confused with instantaneous values. This shows that students do not clearly differentiate variable and direct currents. In this paper we try, with a historical study and a study of teaching the concept of RMS values, to understand students’ difficulties with this concept. In the first part we present an epistemological analysis of the concept of RMS values, showing that it is multifaceted and can be approached from different points of view. In the second part we analyse the evolution of French secondary school curricula and textbooks from the explicit introduction of variable currents to today, questioning the links between the evolution of the curricula and the evolution of the place of science and technology in our societies. We point out that the evolution of the curricula is linked to the social context and to the connections between science, technology and society, and also to the relationship with mathematics curricula. We show that alternating current is introduced earlier in the curriculum but has gradually lost all phenomenological description. This study allows us to better understand students’ difficulties and to discuss some implications for teaching.

Mapping the x-linked lymphoproliferative syndrome

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

Skare, J.C.; Milunsky, A.; Byron, K.S.

1987-04-01

The X-linked lymphoproliferative syndrome is triggered by Epstein-Barr virus infection and results in fatal mononucleosis, immunodeficiency, and lymphoproliferative disorders. This study shows that the mutation responsible for X-linked lymphoproliferative syndrome is genetically linked to a restriction fragment length polymorphism detected with the DXS42 probe (from Xq24-q27). The most likely recombination frequency between the loci is 4%, and the associated logarithm of the odds is 5.26. Haplotype analysis using flanking restriction fragment length polymorphism markers indicates that the locus for X-linked lymphoproliferative syndrome is distal to probe DXS42 but proximal to probe DXS99 (from Xq26-q27). It is now possible to predictmore » which members of a family with X-linked lymphoproliferative syndrome are carrier females and to diagnose the syndrome prenatally.« less

Micro-wear features on unique 100-Mrad cups: two retrieved cups compared to hip simulator wear study.

PubMed

Yamamoto, Kengo; Masaoka, Toshinori; Manaka, Masakazu; Oonishi, Hironobu; Clarke, Ian; Shoji, Hiromu; Kawanabe, Keiichi; Imakiire, Atsuhiro

2004-04-01

We studied the micro-wear phenomena of unique, extensively cross-linked polyethylene cups (cross-linked with 1,000 kGy-irradiation) that had been used briefly in Japan. Two retrievals (at 15 years) came from the Japanese "SOM" hip system (implanted 1971-78). These were compared to a set of 0 kGy and 500-1,500 kGy cups run in our hip simulator. The polyethylene cups that had not been cross-linked had the greatest wear. The worn areas had a burnished appearance and were clearly separated from the unworn region by a distinct ridge-line. The worn areas had lost all machine tracks, showed a large amount of UHMWPE 'flow', and long PE fibrils. The associated surface rippling was degraded. These features were considered synonymous with severe polyethylene wear. In contrast, the worn areas in the very cross-linked cups had a visibly matte surface and no ridge-line. Micro-examination showed that the machine tracks were still present. Ripple formations were less obvious than in the cups that were not cross-linked, polyethylene surface fibrils were scarcer and all the fibrils were much smaller than in the cups that were not crosslinked. Our two retrieved cups and the simulator cups confirmed the greater wear-resistance of very cross-linked polyethylene. It should also be noted that the SOM cup design and processing were unique and differed greatly from that of modern polyethylene cups.

Cross-linking of type I collagen with microbial transglutaminase: identification of cross-linking sites.

PubMed

Stachel, Ines; Schwarzenbolz, Uwe; Henle, Thomas; Meyer, Michael

2010-03-08

Collagen is a popular biomaterial. To deal with its lack of thermal stability and its weak resistance to proteolytic degradation, collagen-based materials are stabilized via different cross-linking procedures. Regarding the potential toxicity of residual cross-linking agents, enzyme-mediated cross-linking would provide an alternative and nontoxic method for collagen stabilization. The results of this study show that type I collagen is a substrate for mTG. However, epsilon-(gamma-glutamyl)lysine cross-links are only incorporated at elevated temperatures when the protein is partially or completely denatured. A maximum number of 5.4 cross-links per collagen monomer were found for heat-denatured collagen. Labeling with the primary amine monodansylcadaverine revealed that at least half of the cross-links are located within the triple helical region of the collagen molecule. Because the triple helix is highly ordered in its native state, this finding might explain why the glutamine residues are inaccessible for mTG under nondenaturing conditions.

Fluorescence imaging of tryptophan and collagen cross-links to evaluate wound closure ex vivo

NASA Astrophysics Data System (ADS)

Wang, Ying; Ortega-Martinez, Antonio; Farinelli, Bill; Anderson, R. R.; Franco, Walfre

2016-02-01

Wound size is a key parameter in monitoring healing. Current methods to measure wound size are often subjective, time-consuming and marginally invasive. Recently, we developed a non-invasive, non-contact, fast and simple but robust fluorescence imaging (u-FEI) method to monitor the healing of skin wounds. This method exploits the fluorescence of native molecules to tissue as functional and structural markers. The objective of the present study is to demonstrate the feasibility of using variations in the fluorescence intensity of tryptophan and cross-links of collagen to evaluate proliferation of keratinocyte cells and quantitate size of wound during healing, respectively. Circular dermal wounds were created in ex vivo human skin and cultured in different media. Two serial fluorescence images of tryptophan and collagen cross-links were acquired every two days. Histology and immunohistology were used to validate correlation between fluorescence and epithelialization. Images of collagen cross-links show fluorescence of the exposed dermis and, hence, are a measure of wound area. Images of tryptophan show higher fluorescence intensity of proliferating keratinocytes forming new epithelium, as compared to surrounding keratinocytes not involved in epithelialization. These images are complementary since collagen cross-links report on structure while tryptophan reports on function. HE and immunohistology show that tryptophan fluorescence correlates with newly formed epidermis. We have established a fluorescence imaging method for studying epithelialization processes during wound healing in a skin organ culture model, our approach has the potential to provide a non-invasive, non-contact, quick, objective and direct method for quantitative measurements in wound healing in vivo.

Chemical crosslinking and mass spectrometry studies of the structure and dynamics of membrane proteins and receptors.

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

Haskins, William E.; Leavell, Michael D.; Lane, Pamela

2005-03-01

Membrane proteins make up a diverse and important subset of proteins for which structural information is limited. In this study, chemical cross-linking and mass spectrometry were used to explore the structure of the G-protein-coupled photoreceptor bovine rhodopsin in the dark-state conformation. All experiments were performed in rod outer segment membranes using amino acid 'handles' in the native protein sequence and thus minimizing perturbations to the native protein structure. Cysteine and lysine residues were covalently cross-linked using commercially available reagents with a range of linker arm lengths. Following chemical digestion of cross-linked protein, cross-linked peptides were identified by accurate mass measurementmore » using liquid chromatography-fourier transform mass spectrometry and an automated data analysis pipeline. Assignments were confirmed and, if necessary, resolved, by tandem MS. The relative reactivity of lysine residues participating in cross-links was evaluated by labeling with NHS-esters. A distinct pattern of cross-link formation within the C-terminal domain, and between loop I and the C-terminal domain, emerged. Theoretical distances based on cross-linking were compared to inter-atomic distances determined from the energy-minimized X-ray crystal structure and Monte Carlo conformational search procedures. In general, the observed cross-links can be explained by re-positioning participating side-chains without significantly altering backbone structure. One exception, between C3 16 and K325, requires backbone motion to bring the reactive atoms into sufficient proximity for cross-linking. Evidence from other studies suggests that residues around K325 for a region of high backbone mobility. These findings show that cross-linking studies can provide insight into the structural dynamics of membrane proteins in their native environment.« less

Rational Design, Synthesis and Evaluation of γ-CD-Containing Cross-Linked Polyvinyl Alcohol Hydrogel as a Prednisone Delivery Platform.

PubMed

Marican, Adolfo; Avila-Salas, Fabián; Valdés, Oscar; Wehinger, Sergio; Villaseñor, Jorge; Fuentealba, Natalia; Arenas-Salinas, Mauricio; Argandoña, Yerko; Carrasco-Sánchez, Verónica; Durán-Lara, Esteban F

2018-03-07

This study describes the in-silico rational design, synthesis and evaluation of cross-linked polyvinyl alcohol hydrogels containing γ-cyclodextrin (γ-CDHSAs) as platforms for the sustained release of prednisone (PDN). Through in-silico studies using semi-empirical quantum mechanical calculations, the effectiveness of 20 dicarboxylic acids to generate a specific cross-linked hydrogel capable of supporting different amounts of γ-cyclodextrin (γ-CD) was evaluated. According to the interaction energies calculated with the in-silico studies, the hydrogel made from PVA cross-linked with succinic acids (SA) was shown to be the best candidate for containing γ-CD. Later, molecular dynamics simulation studies were performed in order to evaluate the intermolecular interactions between PDN and three cross-linked hydrogel formulations with different proportions of γ-CD (2.44%, 4.76% and 9.1%). These three cross-linked hydrogels were synthesized and characterized. The loading and the subsequent release of PDN from the hydrogels were investigated. The in-silico and experimental results showed that the interaction between PDN and γ-CDHSA was mainly produced with the γ-CDs linked to the hydrogels. Thus, the unique structures and properties of γ-CDHSA demonstrated an interesting multiphasic profile that could be utilized as a promising drug carrier for controlled, sustained and localized release of PDN.

Rational Design, Synthesis and Evaluation of γ-CD-Containing Cross-Linked Polyvinyl Alcohol Hydrogel as a Prednisone Delivery Platform

PubMed Central

Marican, Adolfo; Valdés, Oscar; Wehinger, Sergio; Villaseñor, Jorge; Fuentealba, Natalia; Argandoña, Yerko; Carrasco-Sánchez, Verónica

2018-01-01

This study describes the in-silico rational design, synthesis and evaluation of cross-linked polyvinyl alcohol hydrogels containing γ-cyclodextrin (γ-CDHSAs) as platforms for the sustained release of prednisone (PDN). Through in-silico studies using semi-empirical quantum mechanical calculations, the effectiveness of 20 dicarboxylic acids to generate a specific cross-linked hydrogel capable of supporting different amounts of γ-cyclodextrin (γ-CD) was evaluated. According to the interaction energies calculated with the in-silico studies, the hydrogel made from PVA cross-linked with succinic acids (SA) was shown to be the best candidate for containing γ-CD. Later, molecular dynamics simulation studies were performed in order to evaluate the intermolecular interactions between PDN and three cross-linked hydrogel formulations with different proportions of γ-CD (2.44%, 4.76% and 9.1%). These three cross-linked hydrogels were synthesized and characterized. The loading and the subsequent release of PDN from the hydrogels were investigated. The in-silico and experimental results showed that the interaction between PDN and γ-CDHSA was mainly produced with the γ-CDs linked to the hydrogels. Thus, the unique structures and properties of γ-CDHSA demonstrated an interesting multiphasic profile that could be utilized as a promising drug carrier for controlled, sustained and localized release of PDN. PMID:29518980

ARX polyalanine expansions are highly implicated in familial cases of mental retardation with infantile epilepsy and/or hand dystonia.

PubMed

Cossée, Mireille; Faivre, Laurence; Philippe, Christophe; Hichri, Heifa; de Saint-Martin, Anne; Laugel, Vincent; Bahi-Buisson, Nadia; Lemaitre, Jean-François; Leheup, Bruno; Delobel, Bruno; Demeer, Bénédicte; Poirier, Karine; Biancalana, Valérie; Pinoit, Jean-Michel; Julia, Sophie; Chelly, Jamel; Devys, Didier; Mandel, Jean-Louis

2011-01-01

Mutations in the ARX gene cause both nonsyndromic and several forms of syndromic mental retardation (MR). Two polyalanine (polyA) expansions of ARX are recurrent mutations. The most common one, the c.428_451dup, is associated with a wide spectrum of phenotypes, ranging from the most severe West syndrome to Partington syndrome (MR and hand dystonia), and even nonsyndromic X-linked mental retardation (NS-XLMR). Studies of patients not selected for specific clinical signs showed that the c.428_451dup is relatively frequent in families harboring X-linked MR (7.5%), but less common in familial cases compatible with X-linked NR (1%), and very rare in sporadic cases (0.1%). The c.333_334ins(GCG)7 expansion is less frequent and mainly associated with West syndrome. We screened for both ARX polyA expansions in 98 unrelated patients selected for the presence of NR associated with different types of epilepsy and/or with hand dystonia. We also studied two families with an initial diagnosis of NS-XLMR, one of which was identified as showing linkage to the ARX locus. The c.428_451dup was identified in three patients and the c.333_334ins(GCG)7 in one; all of the patients were from families with two affected brothers. We also found the c.428_451dup in the family linked to ARX, and clinical re-evaluation showed subtle, previously undetected signs. Our study illustrates that ARX polyA expansions are primarily associated with syndromic MR and shows a higher yield (18% in our cohort) when these mutations are screened in familial cases of MR with epilepsy and/or dystonia. Copyright © 2010 Wiley-Liss, Inc.

The Role of Executive Functions in Social Cognition among Children with Down Syndrome: Relationship Patterns

PubMed Central

Amadó, Anna; Serrat, Elisabet; Vallès-Majoral, Eduard

2016-01-01

Many studies show a link between social cognition, a set of cognitive and emotional abilities applied to social situations, and executive functions in typical developing children. Children with Down syndrome (DS) show deficits both in social cognition and in some subcomponents of executive functions. However this link has barely been studied in this population. The aim of this study is to investigate the links between social cognition and executive functions among children with DS. We administered a battery of social cognition and executive function tasks (six theory of mind tasks, a test of emotion comprehension, and three executive function tasks) to a group of 30 participants with DS between 4 and 12 years of age. The same tasks were administered to a chronological-age control group and to a control group with the same linguistic development level. Results showed that apart from deficits in social cognition and executive function abilities, children with DS displayed a slight improvement with increasing chronological age and language development in those abilities. Correlational analysis suggested that working memory was the only component that remained constant in the relation patterns of the three groups of participants, being the relation patterns similar among participants with DS and the language development control group. A multiple linear regression showed that working memory explained above 50% of the variability of social cognition in DS participants and in language development control group, whereas in the chronological-age control group this component only explained 31% of the variability. These findings, and specifically the link between working memory and social cognition, are discussed on the basis of their theoretical and practical implications for children with DS. We discuss the possibility to use a working memory training to improve social cognition in this population. PMID:27679588

Environmental Exposures and Parkinson’s Disease

PubMed Central

Nandipati, Sirisha; Litvan, Irene

2016-01-01

Parkinson’s disease (PD) affects millions around the world. The Braak hypothesis proposes that in PD a pathologic agent may penetrate the nervous system via the olfactory bulb, gut, or both and spreads throughout the nervous system. The agent is unknown, but several environmental exposures have been associated with PD. Here, we summarize and examine the evidence for such environmental exposures. We completed a comprehensive review of human epidemiologic studies of pesticides, selected industrial compounds, and metals and their association with PD in PubMed and Google Scholar until April 2016. Most studies show that rotenone and paraquat are linked to increased PD risk and PD-like neuropathology. Organochlorines have also been linked to PD in human and laboratory studies. Organophosphates and pyrethroids have limited but suggestive human and animal data linked to PD. Iron has been found to be elevated in PD brain tissue but the pathophysiological link is unclear. PD due to manganese has not been demonstrated, though a parkinsonian syndrome associated with manganese is well-documented. Overall, the evidence linking paraquat, rotenone, and organochlorines with PD appears strong; however, organophosphates, pyrethroids, and polychlorinated biphenyls require further study. The studies related to metals do not support an association with PD. PMID:27598189

Linking ClinicalTrials.gov and PubMed to Track Results of Interventional Human Clinical Trials

PubMed Central

Huser, Vojtech; Cimino, James J.

2013-01-01

Objective In an effort to understand how results of human clinical trials are made public, we analyze a large set of clinical trials registered at ClinicalTrials.gov, the world’s largest clinical trial registry. Materials and Methods We considered two trial result artifacts: (1) existence of a trial result journal article that is formally linked to a registered trial or (2) the deposition of a trial’s basic summary results within the registry. Results The study sample consisted of 8907 completed, interventional, phase 2-or-higher clinical trials that were completed in 2006-2009. The majority of trials (72.2%) had no structured trial-article link present. A total of 2367 trials (26.6%) deposited basic summary results within the registry. Of those , 969 trials (10.9%) were classified as trials with extended results and 1398 trials (15.7%) were classified as trials with only required basic results. The majority of the trials (54.8%) had no evidence of results, based on either linked result articles or basic summary results (silent trials), while a minimal number (9.2%) report results through both registry deposition and publication. Discussion Our study analyzes the body of linked knowledge around clinical trials (which we refer to as the “trialome”). Our results show that most trials do not report results and, for those that do, there is minimal overlap in the types of reporting. We identify several mechanisms by which the linkages between trials and their published results can be increased. Conclusion Our study shows that even when combining publications and registry results, and despite availability of several information channels, trial sponsors do not sufficiently meet the mandate to inform the public either via a linked result publication or basic results submission. PMID:23874614

Mining Missing Hyperlinks from Human Navigation Traces: A Case Study of Wikipedia.

PubMed

West, Robert; Paranjape, Ashwin; Leskovec, Jure

Hyperlinks are an essential feature of the World Wide Web. They are especially important for online encyclopedias such as Wikipedia: an article can often only be understood in the context of related articles, and hyperlinks make it easy to explore this context. But important links are often missing, and several methods have been proposed to alleviate this problem by learning a linking model based on the structure of the existing links. Here we propose a novel approach to identifying missing links in Wikipedia. We build on the fact that the ultimate purpose of Wikipedia links is to aid navigation. Rather than merely suggesting new links that are in tune with the structure of existing links, our method finds missing links that would immediately enhance Wikipedia's navigability. We leverage data sets of navigation paths collected through a Wikipedia-based human-computation game in which users must find a short path from a start to a target article by only clicking links encountered along the way. We harness human navigational traces to identify a set of candidates for missing links and then rank these candidates. Experiments show that our procedure identifies missing links of high quality.

Mining Missing Hyperlinks from Human Navigation Traces: A Case Study of Wikipedia

PubMed Central

West, Robert; Paranjape, Ashwin; Leskovec, Jure

2015-01-01

Hyperlinks are an essential feature of the World Wide Web. They are especially important for online encyclopedias such as Wikipedia: an article can often only be understood in the context of related articles, and hyperlinks make it easy to explore this context. But important links are often missing, and several methods have been proposed to alleviate this problem by learning a linking model based on the structure of the existing links. Here we propose a novel approach to identifying missing links in Wikipedia. We build on the fact that the ultimate purpose of Wikipedia links is to aid navigation. Rather than merely suggesting new links that are in tune with the structure of existing links, our method finds missing links that would immediately enhance Wikipedia's navigability. We leverage data sets of navigation paths collected through a Wikipedia-based human-computation game in which users must find a short path from a start to a target article by only clicking links encountered along the way. We harness human navigational traces to identify a set of candidates for missing links and then rank these candidates. Experiments show that our procedure identifies missing links of high quality. PMID:26634229

The effects of link format and screen location on visual search of web pages.

PubMed

Ling, Jonathan; Van Schaik, Paul

2004-06-22

Navigation of web pages is of critical importance to the usability of web-based systems such as the World Wide Web and intranets. The primary means of navigation is through the use of hyperlinks. However, few studies have examined the impact of the presentation format of these links on visual search. The present study used a two-factor mixed measures design to investigate whether there was an effect of link format (plain text, underlined, bold, or bold and underlined) upon speed and accuracy of visual search and subjective measures in both the navigation and content areas of web pages. An effect of link format on speed of visual search for both hits and correct rejections was found. This effect was observed in the navigation and the content areas. Link format did not influence accuracy in either screen location. Participants showed highest preference for links that were in bold and underlined, regardless of screen area. These results are discussed in the context of visual search processes and design recommendations are given.

Stabilization of collagen with EDC/NHS in the presence of L-lysine: a comprehensive study.

PubMed

Usha, R; Sreeram, K J; Rajaram, A

2012-02-01

This paper reports the effect of L-lysine on the conformational, rheological, and thermal properties of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) cross linked collagen and investigates the influence of l-lysine on the self assembly processes of collagen. In the absence of L-lysine, the rheological characterization of collagen cross linked with EDC/NHS showed an increase in shearing stress with shearing speed indicating that the collagen chains become rigid and the molecules are reluctant to flow. On the other hand, the increase in shearing stress with shearing speed is comparatively much less in the presence of L-lysine indicating a greater flexibility of the collagen molecules. The self assembly processes of collagen treated with EDC/NHS in the absence and presence of L-lysine were characterized using powder XRD, FT-IR, polarizing optical microscopy and kinetic studies. XRD studies show an increase in peak intensity and sharpness in the presence of L-lysine indicating the enhancement of crystallinity of collagen nano-fibrils. FT-IR results suggest that the incorporation of L-lysine in the EDC/NHS cross linking favors the molecular stability of collagen. From the present study, it is possible to conclude that the pre-treatment of collagen with L-lysine enhances EDC/NHS cross linking and can be used for biomaterial applications. Copyright © 2011 Elsevier B.V. All rights reserved.

The effect of pH on hydrolysis, cross-linking and barrier properties of starch barriers containing citric acid.

PubMed

Olsson, Erik; Menzel, Carolin; Johansson, Caisa; Andersson, Roger; Koch, Kristine; Järnström, Lars

2013-11-06

Citric acid cross-linking of starch for e.g. food packaging applications has been intensely studied during the last decade as a method of producing water-insensitive renewable barrier coatings. We managed to improve a starch formulation containing citric acid as cross-linking agent for industrial paper coating applications by adjusting the pH of the starch solution. The described starch formulations exhibited both cross-linking of starch by citric acid as well as satisfactory barrier properties, e.g. fairly low OTR values at 50% RH that are comparable with EVOH. Furthermore, it has been shown that barrier properties of coated papers with different solution pH were correlated to molecular changes in starch showing both hydrolysis and cross-linking of starch molecules in the presence of citric acid. Hydrolysis was shown to be almost completely hindered at solution pH≥4 at curing temperatures≤105 °C and at pH≥5 at curing temperatures≤150 °C, whereas cross-linking still occurred to some extent at pH≤6.5 and drying temperatures as low as 70 °C. Coated papers showed a minimum in water vapor transmission rate at pH 4 of the starch coating solution, corresponding to the point where hydrolysis was effectively hindered but where a significant degree of cross-linking still occurred. Copyright © 2013 Elsevier Ltd. All rights reserved.

The surprising recovery of red spruce growth shows links to decreased acid deposition and elevated temperature

Treesearch

Alexandra M. Kosiba; Paul G. Schaberg; Shelly A. Rayback; Gary J. Hawley

2018-01-01

Following growth declines and increased mortality linked to acid deposition-induced calcium depletion, red spruce (Picea rubens Sarg.) in the northeastern United States are experiencing a recovery. We found that more than 75% of red spruce trees and 90% of the plots examined in this study exhibited increasing growth since 2001. To understand this...

Development of swellable local implants of a polyethyleneimine-poly(vinyl pyrrolidone) (PEI-PVP) hydrogel as a socket filler.

PubMed

Chang, Ching-Wen; Ho, Hsiu-O; Lo, Yi-June; Lee, Sheng-Yang; Yang, You-Ren; Sheu, Ming-Thau

2012-01-01

In this study, hydrogels composed of polyethyleneimine (PEI) and poly(vinyl pyrrolidone) K90 (PVP) cross-linked with various concentrations (0, 0.125, 0.25 and 0.5%) of glutaraldehyde were evaluated as a hydrogel filler for the local delivery of lidocaine after tooth extraction. The drug-release kinetics, swellability, cytotoxicity and wound healing after tooth extraction of these non-cross-linked and cross-linked PEI-PVP hydrogels were examined in male beagles and compared to values using Spongostan(®). Results demonstrated that the extent of cross-linking influenced the swelling of the resulting hydrogel, but the drug-release rates were similar. No significant changes were observed in gingival fibroblasts in contact with the PEI- PVP hydrogels or Spongostan(®). In the in vivo study, PEI-PVP hydrogels showed good retention in the socket for 2 days and showed comparable wound-healing rates within 2 weeks with those of Spongostan(®). In conclusion, PEI-PVP hydrogels are suitable for use as socket-dressing materials, and the release of local anaesthesia from PEI-PVP hydrogels can be sustained for a desirable period of time to prevent pain after a tooth extraction.

Novel Spray Dried Glycerol 2-Phosphate Cross-Linked Chitosan Microparticulate Vaginal Delivery System—Development, Characterization and Cytotoxicity Studies

PubMed Central

Szymańska, Emilia; Szekalska, Marta; Czarnomysy, Robert; Lavrič, Zoran; Srčič, Stane; Miltyk, Wojciech; Winnicka, Katarzyna

2016-01-01

Chitosan microparticulate delivery systems containing clotrimazole were prepared by a spray drying technique using glycerol 2-phosphate as an ion cross-linker. The impact of a cross-linking ratio on microparticle characteristics was evaluated. Drug-free and drug-loaded unmodified or ion cross-linked chitosan microparticles were examined for the in vitro cytotoxicity in VK2/E6E7 human vaginal epithelial cells. The presence of glycerol 2-phosphate influenced drug loading and encapsulation efficacy in chitosan microparticles. By increasing the cross-linking ratio, the microparticles with lower diameter, moisture content and smoother surface were observed. Mucoadhesive studies displayed that all formulations possessed mucoadhesive properties. The in vitro release profile of clotrimazole was found to alter considerably by changing the glycerol 2-phosphate/chitosan ratio. Results from cytotoxicity studies showed occurrence of apoptotic cells in the presence of chitosan and ion cross-linked chitosan microparticles, followed by a loss of membrane potential suggesting that cell death might go through the mitochondrial apoptotic pathway. PMID:27690062

Impact of observational incompleteness on the structural properties of protein interaction networks

NASA Astrophysics Data System (ADS)

Kuhnt, Mathias; Glauche, Ingmar; Greiner, Martin

2007-01-01

The observed structure of protein interaction networks is corrupted by many false positive/negative links. This observational incompleteness is abstracted as random link removal and a specific, experimentally motivated (spoke) link rearrangement. Their impact on the structural properties of gene-duplication-and-mutation network models is studied. For the degree distribution a curve collapse is found, showing no sensitive dependence on the link removal/rearrangement strengths and disallowing a quantitative extraction of model parameters. The spoke link rearrangement process moves other structural observables, like degree correlations, cluster coefficient and motif frequencies, closer to their counterparts extracted from the yeast data. This underlines the importance to take a precise modeling of the observational incompleteness into account when network structure models are to be quantitatively compared to data.

PP/EPDM-blends by dynamic vulcanization: Influence of increasing peroxide concentration on mechanical, morphological and rheological characteristics

NASA Astrophysics Data System (ADS)

Patermann, S.; Altstädt, V.

2014-05-01

Thermoplastic vulcanizates (TPVs) combine the elastic properties of thermoset cross-linked rubbers with the melt processability of thermoplastics. The most representative examples of this class are the TPVs based on polypropylene (PP) and ethylene-propylenediene terpolymer rubber (EPDM). The PP/EPDM blends were produced by dynamic vulcanization in a continuous extrusion process. The influence of different peroxide concentrations was studied with regard to cross-link density, compression set, tensile strength/elongation at break and morphology. With increasing peroxide concentration, the cross-link density increases, leading to a reduction of the compression set by 50 %. The cross-linked blends show smaller dispersed EPDM particles than the uncured one. With a peroxide concentration between 0.2 and 0.6 % a maximum in tensile strength and elongation at break was found and with increasing peroxide concentration, the complex viscosity of the TPVs decreases. Compared to batch processes, the results show nearly the same trends.

Cross-linkable graphene oxide embedded nanocomposite hydrogel with enhanced mechanics and cytocompatibility for tissue engineering.

PubMed

Liu, Xifeng; Miller, A Lee; Waletzki, Brian E; Lu, Lichun

2018-05-01

Graphene oxide (GO) is an attractive material that can be utilized to enhance the modulus and conductivities of substrates and hydrogels. To covalently cross-link graphene oxide sheets into hydrogels, abundant cross-linkable double bonds were introduced to synthesize the graphene-oxide-tris-acrylate sheet (GO-TrisA). Polyacrylamide (PAM) nanocomposite hydrogels were then fabricated with inherent covalently and permanently cross-linked GO-TrisA sheets. Results showed that the covalently cross-linked GO-TrisA/PAM nanocomposite hydrogel had enhanced mechanical strength, thermo stability compared with GO/PAM hydrogel maintained mainly by hydrogen bonding between PAM chains and GO sheets. In vitro cell study showed that the covalently cross-linked rGO-TrisA/PAM nanocomposite hydrogel had excellent cytocompatibility after in situ reduction. These results suggest that rGO-TrisA/PAM nanocomposite hydrogel holds great potential for tissue engineering applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1247-1257, 2018. © 2018 Wiley Periodicals, Inc.

'Weakest Link' as a Cognitive Vulnerability Within the Hopelessness Theory of Depression in Chinese University Students.

PubMed

Xiao, Jing; Qiu, Yu; He, Yini; Cui, Lixia; Auerbach, Randy P; McWhinnie, Chad M; Yao, Shuqiao

2016-02-01

The current study tested the cognitive vulnerability-stress component of hopelessness theory using a 'weakest link' approach (e.g. an individual is as cognitively vulnerable to depression as his or her most depressogenic attributional style makes him or her) in a sample of Chinese university students. Participants included 520 students in Changsha. During an initial assessment, participants completed measures assessing weakest link, depressive symptoms and occurrence of negative events once a month for 6 months. Results from hierarchical linear modelling analyses showed that higher levels of weakest link scores were associated with greater increases in depressive symptoms following the occurrence of negative events. Higher weakest link level was associated with greater increases in depressive symptoms over time. These results provide support for the applicability of the 'weakest link' approach to the hopelessness theory to Chinese university students. Copyright © 2014 John Wiley & Sons, Ltd.

Is the kinetoplast DNA a percolating network of linked rings at its critical point?

NASA Astrophysics Data System (ADS)

Michieletto, Davide; Marenduzzo, Davide; Orlandini, Enzo

2015-05-01

In this work we present a computational study of the kinetoplast genome, modelled as a large number of semiflexible unknotted loops, which are allowed to link with each other. As the DNA density increases, the systems shows a percolation transition between a gas of unlinked rings and a network of linked loops which spans the whole system. Close to the percolation transition, we find that the mean valency of the network, i.e. the average number of loops which are linked to any one loop, is around three, as found experimentally for the kinetoplast DNA (kDNA). Even more importantly, by simulating the digestion of the network by a restriction enzyme, we show that the distribution of oligomers, i.e. structures formed by a few loops which remain linked after digestion, quantitatively matches experimental data obtained from gel electrophoresis, provided that the density is, once again, close to the percolation transition. With respect to previous work, our analysis builds on a reduced number of assumptions, yet can still fully explain the experimental data. Our findings suggest that the kDNA can be viewed as a network of linked loops positioned very close to the percolation transition, and we discuss the possible biological implications of this remarkable fact.

Neural activity, neural connectivity, and the processing of emotionally valenced information in older adults: links with life satisfaction.

PubMed

Waldinger, Robert J; Kensinger, Elizabeth A; Schulz, Marc S

2011-09-01

This study examines whether differences in late-life well-being are linked to how older adults encode emotionally valenced information. Using fMRI with 39 older adults varying in life satisfaction, we examined how viewing positive and negative images would affect activation and connectivity of an emotion-processing network. Participants engaged most regions within this network more robustly for positive than for negative images, but within the PFC this effect was moderated by life satisfaction, with individuals higher in satisfaction showing lower levels of activity during the processing of positive images. Participants high in satisfaction showed stronger correlations among network regions-particularly between the amygdala and other emotion processing regions-when viewing positive, as compared with negative, images. Participants low in satisfaction showed no valence effect. Findings suggest that late-life satisfaction is linked with how emotion-processing regions are engaged and connected during processing of valenced information. This first demonstration of a link between neural recruitment and late-life well-being suggests that differences in neural network activation and connectivity may account for the preferential encoding of positive information seen in some older adults.

Linking effects of anthropogenic debris to ecological impacts

PubMed Central

Browne, Mark Anthony; Underwood, A. J.; Chapman, M. G.; Williams, Rob; Thompson, Richard C.; van Franeker, Jan A.

2015-01-01

Accelerated contamination of habitats with debris has caused increased effort to determine ecological impacts. Strikingly, most work on organisms focuses on sublethal responses to plastic debris. This is controversial because (i) researchers have ignored medical insights about the mechanisms that link effects of debris across lower levels of biological organization to disease and mortality, and (ii) debris is considered non-hazardous by policy-makers, possibly because individuals can be injured or removed from populations and assemblages without ecological impacts. We reviewed the mechanisms that link effects of debris across lower levels of biological organization to assemblages and populations. Using plastic, we show microplastics reduce the ‘health’, feeding, growth and survival of ecosystem engineers. Larger debris alters assemblages because fishing-gear and tyres kill animals and damage habitat-forming plants, and because floating bottles facilitate recruitment and survival of novel taxa. Where ecological linkages are not known, we show how to establish hypothetical links by synthesizing studies to assess the likelihood of impacts. We also consider how population models examine ecological linkages and guide management of ecological impacts. We show that by focusing on linkages to ecological impacts rather than the presence of debris and its sublethal impacts, we could reduce threats posed by debris. PMID:25904661

Neural Activity, Neural Connectivity, and the Processing of Emotionally-Valenced Information in Older Adults: Links with Life Satisfaction

PubMed Central

Waldinger, Robert J.; Kensinger, Elizabeth A.; Schulz, Marc S.

2013-01-01

This study examines whether differences in late-life well-being are linked to how older adults encode emotionally-valenced information. Using fMRI with 39 older adults varying in life satisfaction, we examined how viewing positive and negative images affected activation and connectivity of an emotion-processing network. Participants engaged most regions within this network more robustly for positive than for negative images, but within the PFC this effect was moderated by life satisfaction, with individuals higher in satisfaction showing lower levels of activity during the processing of positive images. Participants high in satisfaction showed stronger correlations among network regions – particularly between the amygdala and other emotion processing regions – when viewing positive as compared to negative images. Participants low in satisfaction showed no valence effect. Findings suggest that late-life satisfaction is linked with how emotion-processing regions are engaged and connected during processing of valenced information. This first demonstration of a link between neural recruitment and late-life well-being suggests that differences in neural network activation and connectivity may account for the preferential encoding of positive information seen in some older adults. PMID:21590504

Evidence of reduced recombination rate in human regulatory domains.

PubMed

Liu, Yaping; Sarkar, Abhishek; Kheradpour, Pouya; Ernst, Jason; Kellis, Manolis

2017-10-20

Recombination rate is non-uniformly distributed across the human genome. The variation of recombination rate at both fine and large scales cannot be fully explained by DNA sequences alone. Epigenetic factors, particularly DNA methylation, have recently been proposed to influence the variation in recombination rate. We study the relationship between recombination rate and gene regulatory domains, defined by a gene and its linked control elements. We define these links using expression quantitative trait loci (eQTLs), methylation quantitative trait loci (meQTLs), chromatin conformation from publicly available datasets (Hi-C and ChIA-PET), and correlated activity links that we infer across cell types. Each link type shows a "recombination rate valley" of significantly reduced recombination rate compared to matched control regions. This recombination rate valley is most pronounced for gene regulatory domains of early embryonic development genes, housekeeping genes, and constitutive regulatory elements, which are known to show increased evolutionary constraint across species. Recombination rate valleys show increased DNA methylation, reduced doublestranded break initiation, and increased repair efficiency, specifically in the lineage leading to the germ line. Moreover, by using only the overlap of functional links and DNA methylation in germ cells, we are able to predict the recombination rate with high accuracy. Our results suggest the existence of a recombination rate valley at regulatory domains and provide a potential molecular mechanism to interpret the interplay between genetic and epigenetic variations.

Long-term durability of HT-PEM fuel cells based on thermally cross-linked polybenzimidazole

NASA Astrophysics Data System (ADS)

Søndergaard, Tonny; Cleemann, Lars Nilausen; Becker, Hans; Aili, David; Steenberg, Thomas; Hjuler, Hans Aage; Seerup, Larisa; Li, Qingfeng; Jensen, Jens Oluf

2017-02-01

Long-term durability of high temperature polymer electrolyte membrane fuel cells based on thermally cross-linked polybenzimidazole membranes was studied and compared with reference membranes based on linear polybenzimidazole. The test was conducted at 160 °C under constant load currents of 200 mA cm-2 for periods of 1000, 4400, and 13,000 h. Extensive beginning-of-life (BoL) and end-of-test (EoT) characterisation was carried out, and disturbance of the steady state operated cells was minimised by limiting in-line diagnostics to the low-invasive technique of electrochemical impedance spectroscopy (EIS). Up until the operating time of 9200 h, the cell equipped with the cross-linked membrane showed an average degradation rate of 0.5 μV h-1, compared to 2.6 μV h-1 for the reference membrane, though parallel tests for a shorter period of time showed deviations, likely due to malfunctioning contact between layers or cell components. For the full test period of 13,000 h, the average voltage decay rate was about 1.4 and 4.6 μV h-1 for cells equipped with cross-linked and linear polybenzimidazole membranes, respectively. EIS and post-test analysis revealed that the cross-linked membrane showed better stability in terms of area specific resistance due to improved acid retention characteristics.

Temperature dependence of creep compliance of highly cross-linked epoxy: A molecular simulation study

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

Khabaz, Fardin, E-mail: rajesh.khare@ttu.edu; Khare, Ketan S., E-mail: rajesh.khare@ttu.edu; Khare, Rajesh, E-mail: rajesh.khare@ttu.edu

2014-05-15

We have used molecular dynamics (MD) simulations to study the effect of temperature on the creep compliance of neat cross-linked epoxy. Experimental studies of mechanical behavior of cross-linked epoxy in literature commonly report creep compliance values, whereas molecular simulations of these systems have primarily focused on the Young’s modulus. In this work, in order to obtain a more direct comparison between experiments and simulations, atomistically detailed models of the cross-linked epoxy are used to study their creep compliance as a function of temperature using MD simulations. The creep tests are performed by applying a constant tensile stress and monitoring themore » resulting strain in the system. Our results show that simulated values of creep compliance increase with an increase in both time and temperature. We believe that such calculations of the creep compliance, along with the use of time temperature superposition, hold great promise in connecting the molecular insight obtained from molecular simulation at small length- and time-scales with the experimental behavior of such materials. To the best of our knowledge, this work is the first reported effort that investigates the creep compliance behavior of cross-linked epoxy using MD simulations.« less

Resting-state fMRI correlations: From link-wise unreliability to whole brain stability.

PubMed

Pannunzi, Mario; Hindriks, Rikkert; Bettinardi, Ruggero G; Wenger, Elisabeth; Lisofsky, Nina; Martensson, Johan; Butler, Oisin; Filevich, Elisa; Becker, Maxi; Lochstet, Martyna; Kühn, Simone; Deco, Gustavo

2017-08-15

The functional architecture of spontaneous BOLD fluctuations has been characterized in detail by numerous studies, demonstrating its potential relevance as a biomarker. However, the systematic investigation of its consistency is still in its infancy. Here, we analyze within- and between-subject variability and test-retest reliability of resting-state functional connectivity (FC) in a unique data set comprising multiple fMRI scans (42) from 5 subjects, and 50 single scans from 50 subjects. We adopt a statistical framework that enables us to identify different sources of variability in FC. We show that the low reliability of single links can be significantly improved by using multiple scans per subject. Moreover, in contrast to earlier studies, we show that spatial heterogeneity in FC reliability is not significant. Finally, we demonstrate that despite the low reliability of individual links, the information carried by the whole-brain FC matrix is robust and can be used as a functional fingerprint to identify individual subjects from the population. Copyright © 2017 Elsevier Inc. All rights reserved.

Photo-triggered fluorescent theranostic prodrugs as DNA alkylating agents for mechlorethamine release and spatiotemporal monitoring.

PubMed

Cao, Yanting; Pan, Rong; Xuan, Weimin; Wei, Yongyi; Liu, Kejian; Zhou, Jiahong; Wang, Wei

2015-06-28

We describe a new theranostic strategy for selective delivery and spatiotemporal monitoring of mechlorethamine, a DNA alkylating agent. A photo-responsive prodrug is designed and composed of a photolabile o-nitrophenylethyl group, a DNA alkylating mechlorethamine drug and a coumarin fluorophore. Masking of the "N" in mechlorethamine in a positively charged state in the prodrug renders it inactive, non-toxic, selective and non-fluorescent. Indeed, the stable prodrug shows negligible cytotoxicity towards normal cells with and without UV activation and is completely non-fluorescent. However, upon photo-irradiation, the active mechlorethamine is released and induces efficient DNA cross-links, accompanied by a strong fluorescence enhancement (152 fold). Furthermore, DNA cross-linking activity from the release can be transformed into anticancer activity observed in in vitro studies of tumor cells. Importantly, the drug release progress and the movement can be conveniently monitored by fluorescence spectroscopy. The mechanistic study proves that the DNA cross-linking activity is mainly due to the release of DNA alkylating mechlorethamine. Altogether, the studies show the power of the theranostic strategy for efficient therapy in cancer treatment.

Laponite crosslinked starch/polyvinyl alcohol hydrogels by freezing/thawing process and studying their cadmium ion absorption.

PubMed

Yu, Chen; Tang, Xiaozhi; Liu, Shaowei; Yang, Yuling; Shen, Xinchun; Gao, Chengcheng

2018-05-22

In this study, Laponite RD (LRD) cross-linked hydrogels consisting of starch, polyvinyl alcohol (PVA) were prepared by freezing/thawing process and the influence of LRD content on structure and properties of hydrogels was investigated. FTIR showed a new structure of hydrogen bonding might result from cross-linking reactions between LRD and polymers. X-ray diffraction (XRD) analysis showed that high degree of exfoliation of LRD clay layers had occurred during the preparation of hydrogels. The synergistic effect of physical cross-linking by freeze/thaw cycles and by LRD led to more porous, uniform and stable network, which was shown in SEM images. The melting temperature decreased and thermal stability got improved with the increase of LRD content. Reswelling ratios of hydrogels had the highest value when LRD content was 10%. Additionally, cadmium ion absorption capacity of the hydrogel was studied and the results showed that increasing the concentration of LRD increased absorption ratio and amount of Cd 2+ ion in the solution. In a word, LRD could be used as a physical crosslinker and reinforced agent for starch-PVA based hydrogels and the formed hydrogels could be used as novel type and high capacity absorbent materials in heavy metal removing processes. Copyright © 2018. Published by Elsevier B.V.

Combinatorial Approach for Large-scale Identification of Linked Peptides from Tandem Mass Spectrometry Spectra*

PubMed Central

Wang, Jian; Anania, Veronica G.; Knott, Jeff; Rush, John; Lill, Jennie R.; Bourne, Philip E.; Bandeira, Nuno

2014-01-01

The combination of chemical cross-linking and mass spectrometry has recently been shown to constitute a powerful tool for studying protein–protein interactions and elucidating the structure of large protein complexes. However, computational methods for interpreting the complex MS/MS spectra from linked peptides are still in their infancy, making the high-throughput application of this approach largely impractical. Because of the lack of large annotated datasets, most current approaches do not capture the specific fragmentation patterns of linked peptides and therefore are not optimal for the identification of cross-linked peptides. Here we propose a generic approach to address this problem and demonstrate it using disulfide-bridged peptide libraries to (i) efficiently generate large mass spectral reference data for linked peptides at a low cost and (ii) automatically train an algorithm that can efficiently and accurately identify linked peptides from MS/MS spectra. We show that using this approach we were able to identify thousands of MS/MS spectra from disulfide-bridged peptides through comparison with proteome-scale sequence databases and significantly improve the sensitivity of cross-linked peptide identification. This allowed us to identify 60% more direct pairwise interactions between the protein subunits in the 20S proteasome complex than existing tools on cross-linking studies of the proteasome complexes. The basic framework of this approach and the MS/MS reference dataset generated should be valuable resources for the future development of new tools for the identification of linked peptides. PMID:24493012

FTD and ALS: genetic ties that bind.

PubMed

Orr, Harry T

2011-10-20

Curiously, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), seemingly disparate neurodegenerative disorders, can be inherited together. Two groups (DeJesus-Hernandez et al. and Renton et al.) show that the long sought after ALS/FTD mutation on chromosomal region 9p is a hexanucleotide expansion in C90RF72. These studies, plus a study on X-linked ALS/FTD, provide molecular starting points for identifying pathways that link ALS and FTD pathogenesis. Copyright © 2011 Elsevier Inc. All rights reserved.

Relative entropy as a universal metric for multiscale errors

NASA Astrophysics Data System (ADS)

Chaimovich, Aviel; Shell, M. Scott

2010-06-01

We show that the relative entropy, Srel , suggests a fundamental indicator of the success of multiscale studies, in which coarse-grained (CG) models are linked to first-principles (FP) ones. We demonstrate that Srel inherently measures fluctuations in the differences between CG and FP potential energy landscapes, and develop a theory that tightly and generally links it to errors associated with coarse graining. We consider two simple case studies substantiating these results, and suggest that Srel has important ramifications for evaluating and designing coarse-grained models.

Relative entropy as a universal metric for multiscale errors.

PubMed

Chaimovich, Aviel; Shell, M Scott

2010-06-01

We show that the relative entropy, Srel, suggests a fundamental indicator of the success of multiscale studies, in which coarse-grained (CG) models are linked to first-principles (FP) ones. We demonstrate that Srel inherently measures fluctuations in the differences between CG and FP potential energy landscapes, and develop a theory that tightly and generally links it to errors associated with coarse graining. We consider two simple case studies substantiating these results, and suggest that Srel has important ramifications for evaluating and designing coarse-grained models.

Knowledge Representation and Management: a Linked Data Perspective.

PubMed

Barros, M; Couto, F M

2016-11-10

Biomedical research is increasingly becoming a data-intensive science in several areas, where prodigious amounts of data is being generated that has to be stored, integrated, shared and analyzed. In an effort to improve the accessibility of data and knowledge, the Linked Data initiative proposed a well-defined set of recommendations for exposing, sharing and integrating data, information and knowledge, using semantic web technologies. The main goal of this paper is to identify the current status and future trends of knowledge representation and management in Life and Health Sciences, mostly with regard to linked data technologies. We selected three prominent linked data studies, namely Bio2RDF, Open PHACTS and EBI RDF platform, and selected 14 studies published after 2014 (inclusive) that cited any of the three studies. We manually analyzed these 14 papers in relation to how they use linked data techniques. The analyses show a tendency to use linked data techniques in Life and Health Sciences, and even if some studies do not follow all of the recommendations, many of them already represent and manage their knowledge using RDF and biomedical ontologies. These insights from RDF and biomedical ontologies are having a strong impact on how knowledge is generated from biomedical data, by making data elements increasingly connected and by providing a better description of their semantics. As health institutes become more data centric, we believe that the adoption of linked data techniques will continue to grow and be an effective solution to knowledge representation and management.

Facile fabrication of core cross-linked micelles by RAFT polymerization and enzyme-mediated reaction.

PubMed

Wu, Yukun; Lai, Quanyong; Lai, Shuqi; Wu, Jing; Wang, Wei; Yuan, Zhi

2014-06-01

Polymeric micelles formed in aqueous solution by assembly of amphiphilic block copolymers have been extensively investigated due to their great potential as drug carriers. However, the stability of polymeric assembly is still one of the major challenges in delivering drugs to tissues and cells. Here, we report a facile route to fabricate core cross-linked (CCL) micelles using an enzymatic polymerization as the cross-linking method. We present synthesis of poly(ethylene glycol)-block-poly(N-isopropyl acrylamide-co-N-(4-hydroxyphenethyl) acrylamide) diblock copolymer PEG-b-P(NIPAAm-co-NHPAAm) via reversible addition-fragmentation chain transfer (RAFT) polymerization. The diblock copolymer was then self-assembled into non-cross-linked (NCL) micelles upon heating above the lower critical solution temperature (LCST), and subsequently cross-linked using horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) as enzyme and oxidant. The characterization of the diblock copolymer and micelles were studied by NMR, DLS, UV-vis, and fluorescence spectroscopy. The fluorescence study reveals that the cross-linking process endows the micelles with much lower critical micelle concentration (CMC). In addition, the drug release study shows that the CCL micelles have lower release amount of doxorubicin (DOX) than the NCL micelles due to the enhanced stability of the CCL micelles by core cross-linking process. Copyright © 2014 Elsevier B.V. All rights reserved.

Undoing the past in order to lie in the present: Counterfactual thinking and deceptive communication.

PubMed

Briazu, Raluca A; Walsh, Clare R; Deeprose, Catherine; Ganis, Giorgio

2017-04-01

This paper explores the proposal that there is a close link between counterfactual thinking and lying. Both require the imagination of alternatives to reality and we describe four studies which explore this link. In Study 1 we measured individual differences in both abilities and found that individuals with a tendency to generate counterfactual thoughts were also more likely to generate potential lies. Studies 2 and 3 showed that counterfactual availability influences people's ability to come up with lies and the extent to which they expect others to lie. Study 4 used a behavioural measure of deception to show that people tend to lie more in situations also known to elicit counterfactual thoughts. Overall, the results show that the imagination of alternatives to the past plays an important role in the generation of lies. We discuss the implications for the fields of counterfactual thinking and deception. Copyright © 2017 Elsevier B.V. All rights reserved.

Novel electrospun nanofibers of modified gelatin-tyrosine in cartilage tissue engineering.

PubMed

Agheb, Maria; Dinari, Mohammad; Rafienia, Mohammad; Salehi, Hossein

2017-02-01

In natural cartilage tissues, chondrocytes are linked to extracellular matrix (ECM) through cell-surface binding proteins. Surface modification of gelatin can provide a new generation of biopolymers and fibrous scaffolds with chemical, mechanical, and biological properties. In this study tyrosine protein and 1,2,3-triazole ring were utilized to functionalize gelatin without Cu catalyst. Their molecular structure was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy ( 1 HNMR). Chemical cross-linkers such as glutaraldehyde (GA) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysulfosuccinimide (NHS) were used to electrospin the modified gelatin. The modification of gelatin and cross-linking effects were confirmed by scanning electron microscopy (SEM), contact angle measurement, and mechanical tests. MTT assay using chondrocyte cells showed cell viability of electrospun modified gelatin scaffolds. In vitro cell culture studies showed that electrospun engineered protein scaffolds would support the attachment and growth of cells. The results also showed that cross-linked nanofibers with EDC/NHS could be considered excellent matrices in cell adhesion and proliferation before electrospinning process and their potential substrate in tissue engineering applications, especially in the field of cartilage engineering. Copyright © 2016. Published by Elsevier B.V.

New estradiol-linked nitrosoureas: can the pharmacokinetic properties help to explain the pharmacodynamic activities?

PubMed

Betsch, B; Berger, M R; Spiegelhalder, B; Eisenbrand, G; Schmähl, D

1989-01-01

The pharmacokinetics of 1-(2-chloroethyl)-1-nitrosocarbamoyl-L-alanine-estradiol-17-ester (CNC-alanine-estradiol-17-ester) a new estradiol-linked anticancer drug and the unlinked DNA-crosslinking agent 1-(2-chloroethyl)-1-nitrosocarbamoyl-L-alanine (CNC-alanine) have been studied in methylnitrosourea-induced female Sprague-Dawley rats after equimolar intravenous and oral administration. In comparison with the unlinked single agent, the CNC-alanine-estradiol-17-ester showed a 3-fold longer halflife in plasma and a three times larger volume of distribution. The distribution after intravenous administration was nearly three times faster. The absorption after peroral administration was likewise two times faster. The bioavailability of the estradiol-linked drug was determined to be 52%. After application of CNC-alanine-estradiol-17-ester the cytostatic metabolite CNC-alanine was found, indicating the cleavage of the ester bond. CNC-alanine generated from CNC-alanine-estradiol-17-ester showed a 50% longer halflife than when applied directly. The results indicate that linking 2-chloroethyl-nitrosoureas to estradiol can result in new anticancer agents with modified properties in comparison to the unlinked single agent. The higher antineoplastic activity of the hormone-linked drug can mainly be attributed to differences in the pharmacokinetic behaviour.

Gender and Modes of Collaboration in an Engineering Classroom: A Profile of Two Women on Student Teams.

ERIC Educational Resources Information Center

Ingram, Sandra; Parker, Anne

2002-01-01

Profiles two women from student engineering teams who participated in a study on collaboration and the role of gender. Shows that men and women alike displayed both gender-linked and non-gender-linked behavior, and that successful collaboration was influenced less by gender and more by such factors as a strong work ethic, team commitment, and…

K-Lysine acetyltransferase 2a regulates a hippocampal gene expression network linked to memory formation

PubMed Central

Stilling, Roman M; Rönicke, Raik; Benito, Eva; Urbanke, Hendrik; Capece, Vincenzo; Burkhardt, Susanne; Bahari-Javan, Sanaz; Barth, Jonas; Sananbenesi, Farahnaz; Schütz, Anna L; Dyczkowski, Jerzy; Martinez-Hernandez, Ana; Kerimoglu, Cemil; Dent, Sharon YR; Bonn, Stefan; Reymann, Klaus G; Fischer, Andre

2014-01-01

Neuronal histone acetylation has been linked to memory consolidation, and targeting histone acetylation has emerged as a promising therapeutic strategy for neuropsychiatric diseases. However, the role of histone-modifying enzymes in the adult brain is still far from being understood. Here we use RNA sequencing to screen the levels of all known histone acetyltransferases (HATs) in the hippocampal CA1 region and find that K-acetyltransferase 2a (Kat2a)—a HAT that has not been studied for its role in memory function so far—shows highest expression. Mice that lack Kat2a show impaired hippocampal synaptic plasticity and long-term memory consolidation. We furthermore show that Kat2a regulates a highly interconnected hippocampal gene expression network linked to neuroactive receptor signaling via a mechanism that involves nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). In conclusion, our data establish Kat2a as a novel and essential regulator of hippocampal memory consolidation. PMID:25024434

Diagnosis of sleep apnea in patients with stable chronic heart failure using a portable sleep test diagnostic device.

PubMed

Araújo, Inês; Marques, Filipa; André, Sandra; Araújo, Manuel; Marques, Sara; Ferreira, Rita; Moniz, Patrícia; Proença, Margarida; Borrego, Pedro; Fonseca, Cândida

2018-01-17

ApneaLink is a portable device for the screening of sleep apnea, a prevalent and underdiagnosed comorbidity in heart failure patients. A prospective cross-sectional study in patients with chronic heart failure was carried out to assess the sensitivity and specificity of apnea-hypopnea index (AHI) measurements using ApneaLink against the standard polysomnography test. Adult patients with a prior hospitalization in an acute heart failure hospital unit were recruited for the study. All participants were tested for sleep apnea using ApneaLink and polysomnography simultaneously during an overnight stay at a sleep laboratory. Global sleep apnea was evaluated according to the AHI, which was analyzed and compared. Subpopulation comparison based on ejection fraction was not realized due to population size. Thirty-five patients with stable chronic heart failure completed the study (mean age 70.9 ± 10.5 years and body mass index 30.0 ± 4.7 kg/m 2 ). Two patients were excluded due to insufficient study duration. ApneaLink had a sensitivity greater than 80% for all AHI measurements, and a specificity greater than 80% for all AHI measurements, except for AHI ≥ 5 events/h (61.5%). The results showed higher sensitivities and specificities at AHI values of ≥ 10 events/h (sensitivity 81.3% and specificity 84.2%) and ≥ 15 events/h (sensitivity 83.3% and specificity 91.3%). Correlation analysis showed that AHI measurements using ApneaLink and polysomnography had a strong and significant correlation (r = 0.794; P < 0.001). Our results suggest that ApneaLink could be used in clinical practice to identify heart failure patients with high (AHI ≥ 15 events/h) and low (AHI < 5 events/h) probability of having sleep apnea, sparing the need for a diagnostic polysomnography and thus potentially impacting prognosis by providing a more cost-effective and timely diagnosis of this non-cardiac comorbidity.

Revisiting the relationship between environmental and financial performance in Chinese industry.

PubMed

Qi, G Y; Zeng, S X; Shi, Jonathan J; Meng, X H; Lin, H; Yang, Q X

2014-12-01

The debate on the relationship between corporate or industrial environmental performance (EP) and financial performance (FP) has yet to be resolved, and studies need to examine the possible moderating effects on the EP-FP link. We argue that industrial EP has a positive effect on FP and that industrial munificence and resource slack can moderate the EP-FP link. Using a dataset from Chinese industrial firms, we examine the direct effect of industrial EP on FP and the indirect effects of industrial munificence and resource slack on the EP-FP link. Our results show that improving corporate or industrial-level EP significantly influences FP and that slack resources play a significant role on the EP-FP link. However, we found no significant moderating effect of industrial munificence on the link. Copyright © 2014 Elsevier Ltd. All rights reserved.

Retweets as a Predictor of Relationships among Users on Social Media.

PubMed

Tsugawa, Sho; Kito, Kosuke

2017-01-01

Link prediction is the problem of detecting missing links or predicting future link formation in a network. Application of link prediction to social media, such as Twitter and Facebook, is useful both for developing novel services and for sociological analyses. While most existing research on link prediction uses only the social network topology for the prediction, in social media, records of user activities such as posting, replying, and reposting are available. These records are expected to reflect user interest, and so incorporating them should improve link prediction. However, research into link prediction using the records of user activities is still in its infancy, and the effectiveness of such records for link prediction has not been fully explored. In this study, we focus in particular on records of reposting as a promising source that could be useful for link prediction, and investigate their effectiveness for link prediction on the popular social media platform Twitter. Our results show that (1) the prediction accuracy of techniques using reposting records is higher than that of popular topology-based techniques such as common neighbors and resource allocation for actively retweeting users, (2) the accuracy of link prediction techniques that use network topology alone can be improved by incorporating reposting records.

Retweets as a Predictor of Relationships among Users on Social Media

PubMed Central

Kito, Kosuke

2017-01-01

Link prediction is the problem of detecting missing links or predicting future link formation in a network. Application of link prediction to social media, such as Twitter and Facebook, is useful both for developing novel services and for sociological analyses. While most existing research on link prediction uses only the social network topology for the prediction, in social media, records of user activities such as posting, replying, and reposting are available. These records are expected to reflect user interest, and so incorporating them should improve link prediction. However, research into link prediction using the records of user activities is still in its infancy, and the effectiveness of such records for link prediction has not been fully explored. In this study, we focus in particular on records of reposting as a promising source that could be useful for link prediction, and investigate their effectiveness for link prediction on the popular social media platform Twitter. Our results show that (1) the prediction accuracy of techniques using reposting records is higher than that of popular topology-based techniques such as common neighbors and resource allocation for actively retweeting users, (2) the accuracy of link prediction techniques that use network topology alone can be improved by incorporating reposting records. PMID:28107489

The space-math link in preschool boys and girls: Importance of mental transformation, targeting accuracy, and spatial anxiety.

PubMed

Wong, Wang I

2017-06-01

Spatial abilities are pertinent to mathematical competence, but evidence of the space-math link has largely been confined to older samples and intrinsic spatial abilities (e.g., mental transformation). The roles of gender and affective factors are also unclear. This study examined the correlations between counting ability, mental transformation, and targeting accuracy in 182 Hong Kong preschoolers, and whether these relationships were weaker at higher spatial anxiety levels. Both spatial abilities related with counting similarly for boys and girls. Targeting accuracy also mediated the male advantage in counting. Interestingly, spatial anxiety moderated the space-math links, but differently for boys and girls. For boys, spatial abilities were irrelevant to counting at high anxiety levels; for girls, the role of anxiety on the space-math link is less clear. Results extend the evidence base of the space-math link to include an extrinsic spatial ability (targeting accuracy) and have implications for intervention programmes. Statement of contribution What is already known on this subject? Much evidence of a space-math link in adolescent and adult samples and for intrinsic spatial abilities. What does this study add? Extended the space-math link to include both intrinsic and extrinsic spatial abilities in a preschool sample. Showed how spatial anxiety moderated the space-math link differently for boys and girls. © 2016 The British Psychological Society.

Assessing the relationship between eating disorder psychopathology and autistic traits in a non-clinical adult population.

PubMed

Carton, Amelia Myri; Smith, Alastair D

2014-01-01

Previous research demonstrates a genetic and behavioural link between eating disorders and autism spectrum disorders, and a recent study (Coombs et al. in Br J Clin Psychol 50:326-338, 2011) extends this link to typical populations, showing a positive correlation between behaviours in typically developing children. The purpose of the present study was to examine whether this relationship continues beyond development, by studying the link between behaviours in a non-clinical adult population. We examined associations between performance on measures relating to autistic traits and disordered eating. Undergraduate students, equally balanced by gender and by subject studied (i.e. humanity or science), completed three tasks: to measure autistic traits, participants were administered the Embedded Figures Test (EFT) and the Autism-Spectrum Quotient (AQ). Eating disorder symptomatology was measured by the Eating Attitudes Test (Eat-26). Our data revealed a significant positive correlation between scores on the AQ and Eat-26. Multiple linear regressions showed that higher scores on the AQ were particularly associated with higher scores on the Bulimia & Food Preoccupation subscale of the Eat-26. EFT performance was positively related to behaviours associated with autism and eating disorders, although not reliably so. These data support the broader link between autistic traits and disordered eating in the non-clinical population, and demonstrate that it extends into adulthood (a time at which autistic behaviours can decrease). This work carries implications for the development of cognitive therapies for people with eating disorders.

Hydrolyzable tannins with the hexahydroxydiphenoyl unit and the m-depsidic link: HPLC-DAD-MS identification and model synthesis.

PubMed

Arapitsas, Panagiotis; Menichetti, Stefano; Vincieri, Franco F; Romani, Annalisa

2007-01-10

This study was designed to develop efficient analytical tools for the difficult HPLC-DAD-MS identification of hydrolyzable tannins in natural tissue extracts. Throughout the study of the spectroscopic characteristics of properly synthesized stereodefined standards, it was observed that the UV-vis spectra of compounds with the m-depsidic link showed a characteristic shoulder at 300 nm, consistent with the simple glucogalloyl esters, whereas compounds with the hexahydroxydiphenoyl (HHDP) unit gave a diagnostic fragmentation pattern, caused by a spontaneous lactonization in the mass spectrometer. These observations were confirmed by HPLC-DAD-MS analyses of tannic acid and raspberry extracts, which are rich in hydrolyzable tannins with the m-depsidic link and the HHDP unit, respectively.

Link prediction with node clustering coefficient

NASA Astrophysics Data System (ADS)

Wu, Zhihao; Lin, Youfang; Wang, Jing; Gregory, Steve

2016-06-01

Predicting missing links in incomplete complex networks efficiently and accurately is still a challenging problem. The recently proposed Cannistrai-Alanis-Ravai (CAR) index shows the power of local link/triangle information in improving link-prediction accuracy. Inspired by the idea of employing local link/triangle information, we propose a new similarity index with more local structure information. In our method, local link/triangle structure information can be conveyed by clustering coefficient of common-neighbors directly. The reason why clustering coefficient has good effectiveness in estimating the contribution of a common-neighbor is that it employs links existing between neighbors of a common-neighbor and these links have the same structural position with the candidate link to this common-neighbor. In our experiments, three estimators: precision, AUP and AUC are used to evaluate the accuracy of link prediction algorithms. Experimental results on ten tested networks drawn from various fields show that our new index is more effective in predicting missing links than CAR index, especially for networks with low correlation between number of common-neighbors and number of links between common-neighbors.

Interstaple Dithiol Cross-Linking in Au(25)(SR)(18) Nanomolecules: A Combined Mass Spectrometric and Computational Study

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

Jiang, Deen; Dass, Amala; Tschumper, Gregory

2011-01-01

A systematic study of cross-linking chemistry of the Au{sub 25}(SR){sub 18} nanomolecule by dithiols of varying chain length, HS-(CH2)n-SH where n = 2, 3, 4, 5, and 6, is presented here. Monothiolated Au{sub 25} has six [RSAuSRAuSR] staple motifs on its surface, and MALDI mass spectrometry data of the ligand exchanged clusters show that propane (C3) and butane (C4) dithiols have ideal chain lengths for interstaple cross-linking and that up to six C3 or C4 dithiols can be facilely exchanged onto the cluster surface. Propanedithiol predominately exchanges with two monothiols at a time, making cross-linking bridges, while butanedithiol can exchangemore » with either one or two monothiols at a time. The extent of cross-linking can be controlled by the Au{sub 25}(SR){sub 18} to dithiol ratio, the reaction time of ligand exchange, or the addition of a hydrophobic tail to the dithiol. MALDI MS suggests that during ethane (C2) dithiol exchange, two ethanedithiols become connected by a disulfide bond; this result is supported by density functional theory (DFT) prediction of the optimal chain length for the intrastaple coupling. Both optical absorption spectroscopy and DFT computations show that the electronic structure of the Au{sub 25} nanomolecule retains its main features after exchange of up to eight monothiol ligands.« less

Influence of enzymes and surfactants on the disintegration behavior of cross-linked hard gelatin capsules during dissolution.

PubMed

Pennings, F H; Kwee, B L S; Vromans, H

2006-01-01

Gelatin exhibits cross-linking upon storage at stress conditions. Capsules stored at these conditions fail to show appropriate in vitro dissolution. The aim of this study is to show the effect of surfactants in the medium on the disintegration of the gelatin capsule. This is demonstrated in the presence and absence of the enzymes pancreatin and pepsin, the function of which is to improve the dissolution. Sodium lauryl sulfate (SLS) and Tween 80 are tested as surfactants. When SLS is used in the medium, dissolution is significantly hampered due to the formation of a less soluble precipitate of gelatin. Compared to SLS, Tween 80 shows far better disintegration and solubility results in dissolution media with neutral or low pH. Therefore, it is concluded in this study that Tween 80 is preferred when a surfactant is necessary to comply with sink condition requirements.

Linking effects of anthropogenic debris to ecological impacts.

PubMed

Browne, Mark Anthony; Underwood, A J; Chapman, M G; Williams, Rob; Thompson, Richard C; van Franeker, Jan A

2015-05-22

Accelerated contamination of habitats with debris has caused increased effort to determine ecological impacts. Strikingly, most work on organisms focuses on sublethal responses to plastic debris. This is controversial because (i) researchers have ignored medical insights about the mechanisms that link effects of debris across lower levels of biological organization to disease and mortality, and (ii) debris is considered non-hazardous by policy-makers, possibly because individuals can be injured or removed from populations and assemblages without ecological impacts. We reviewed the mechanisms that link effects of debris across lower levels of biological organization to assemblages and populations. Using plastic, we show microplastics reduce the 'health', feeding, growth and survival of ecosystem engineers. Larger debris alters assemblages because fishing-gear and tyres kill animals and damage habitat-forming plants, and because floating bottles facilitate recruitment and survival of novel taxa. Where ecological linkages are not known, we show how to establish hypothetical links by synthesizing studies to assess the likelihood of impacts. We also consider how population models examine ecological linkages and guide management of ecological impacts. We show that by focusing on linkages to ecological impacts rather than the presence of debris and its sublethal impacts, we could reduce threats posed by debris. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Bioinspired Coordination Micelles Integrating High Stability, Triggered Cargo Release, and Magnetic Resonance Imaging.

PubMed

Xin, Keting; Li, Man; Lu, Di; Meng, Xuan; Deng, Jun; Kong, Deling; Ding, Dan; Wang, Zheng; Zhao, Yanjun

2017-01-11

Catechol-Fe 3+ coordinated micelles show the potential for achieving on-demand drug delivery and magnetic resonance imaging in a single nanoplatform. Herein, we developed bioinspired coordination-cross-linked amphiphilic polymeric micelles loaded with a model anticancer agent, doxorubicin (Dox). The nanoscale micelles could tolerate substantial dilution to a condition below the critical micelle concentration (9.4 ± 0.3 μg/mL) without sacrificing the nanocarrier integrity due to the catechol-Fe 3+ coordinated core cross-linking. Under acidic conditions (pH 5.0), the release rate of Dox was significantly faster compared to that at pH 7.4 as a consequence of coordination collapse and particle de-cross-linking. The cell viability study in 4T1 cells showed no toxicity regarding placebo cross-linked micelles. The micelles with improved stability showed a dramatically increased Dox accumulation in tumors and hence the enhanced suppression of tumor growth in a 4T1 tumor-bearing mouse model. The presence of Fe 3+ endowed the micelles T 1 -weighted MRI capability both in vitro and in vivo without the incorporation of traditional toxic paramagnetic contrast agents. The current work presented a simple "three birds with one stone" approach to engineer the robust theranostic nanomedicine platform.

Cell phones and cancer

MedlinePlus

Cancer and cell phones; Do cell phones cause cancer? ... Several major studies show no link between cell phones and cancer at this time. However, since the information available is based on short-term studies, the impact of many years of ...

Feel like you belong: on the bidirectional link between emotional fit and group identification in task groups

PubMed Central

Delvaux, Ellen; Meeussen, Loes; Mesquita, Batja

2015-01-01

Three studies investigated the association between members’ group identification and the emotional fit with their group. In the first study, a cross-sectional study in a large organization, we replicated earlier research by showing that group identification and emotional fit are positively associated, using a broader range of emotions and using profile correlations to measure group members’ emotional fit. In addition, in two longitudinal studies, where groups of students were followed at several time points during their collaboration on a project, we tested the directionality of the relationship between group identification and emotional fit. The results showed a bidirectional, positive link between group identification and emotional fit, such that group identification and emotional fit either mutually reinforce or mutually dampen each other over time. We discuss how these findings increase insights in group functioning and how they may be used to change group processes for better or worse. PMID:26300806

Cooperation and competition in business on example of Internet research of opto-electronic companies

NASA Astrophysics Data System (ADS)

Kaliczyńska, Małgorzata

2006-10-01

Based on findings from earlier studies which showed that links to academic web sites contain important information, the following study examines the practicability of using co-link data to describe cooperation and competition in optoelec-tronic business. The analysis was based on 32 companies and organizations which were found in an issue of a specialist magazine. For the purpose of the research three search engines - Google, Yahoo! and MSN Search were used. Assuming that a number of co-links to a pair of Web sites is a measure of the similarity between the two companies, the study aims at search for the sets of companies that would be similar to one another. The method applied is the MDS - multidimensional scaling that allows to present results of the analysis on a 2D map.

Knowledge Representation and Management: A Linked Data Perspective

PubMed Central

Barros, M.

2016-01-01

Summary Introduction Biomedical research is increasingly becoming a data-intensive science in several areas, where prodigious amounts of data is being generated that has to be stored, integrated, shared and analyzed. In an effort to improve the accessibility of data and knowledge, the Linked Data initiative proposed a well-defined set of recommendations for exposing, sharing and integrating data, information and knowledge, using semantic web technologies. Objective The main goal of this paper is to identify the current status and future trends of knowledge representation and management in Life and Health Sciences, mostly with regard to linked data technologies. Methods We selected three prominent linked data studies, namely Bio2RDF, Open PHACTS and EBI RDF platform, and selected 14 studies published after 2014 (inclusive) that cited any of the three studies. We manually analyzed these 14 papers in relation to how they use linked data techniques. Results The analyses show a tendency to use linked data techniques in Life and Health Sciences, and even if some studies do not follow all of the recommendations, many of them already represent and manage their knowledge using RDF and biomedical ontologies. Conclusion These insights from RDF and biomedical ontologies are having a strong impact on how knowledge is generated from biomedical data, by making data elements increasingly connected and by providing a better description of their semantics. As health institutes become more data centric, we believe that the adoption of linked data techniques will continue to grow and be an effective solution to knowledge representation and management. PMID:27830248

VCSEL-based fiber optic link for avionics: implementation and performance analyses

NASA Astrophysics Data System (ADS)

Shi, Jieqin; Zhang, Chunxi; Duan, Jingyuan; Wen, Huaitao

2006-11-01

A Gb/s fiber optic link with built-in test capability (BIT) basing on vertical-cavity surface-emitting laser (VCSEL) sources for military avionics bus for next generation has been presented in this paper. To accurately predict link performance, statistical methods and Bit Error Rate (BER) measurements have been examined. The results show that the 1Gb/s fiber optic link meets the BER requirement and values for link margin can reach up to 13dB. Analysis shows that the suggested photonic network may provide high performance and low cost interconnections alternative for future military avionics.

Barium-cross-linked alginate-gelatine microcapsule as a potential platform for stem cell production and modular tissue formation.

PubMed

Alizadeh Sardroud, Hamed; Nemati, Sorour; Baradar Khoshfetrat, Ali; Nabavinia, Mahbobeh; Beygi Khosrowshahi, Younes

2017-08-01

Influence of gelatine concentration and cross-linker ions of Ca 2+ and Ba 2+ was evaluated on characteristics of alginate hydrogels and proliferation behaviours of model adherent and suspendable stem cells of fibroblast and U937 embedded in alginate microcapsules. Increasing gelatine concentration to 2.5% increased extent of swelling to 15% and 25% for barium- and calcium-cross-linked hydrogels, respectively. Mechanical properties also decreased with increasing swelling of hydrogels. Both by increasing gelatine concentration and using barium ions increased considerably the proliferation of encapsulated model stem cells. Barium-cross-linked alginate-gelatine microcapsule tested for bone building block showed a 13.5 ± 1.5-fold expansion for osteoblast cells after 21 days with deposition of bone matrix. The haematopoietic stem cells cultured in the microcapsule after 7 days also showed up to 2-fold increase without adding any growth factor. The study demonstrates that barium-cross-linked alginate-gelatine microcapsule has potential for use as a simple and efficient 3D platform for stem cell production and modular tissue formation.

Characterization of demographic expansions from pairwise comparisons of linked microsatellite haplotypes.

PubMed

Navascués, Miguel; Hardy, Olivier J; Burgarella, Concetta

2009-03-01

This work extends the methods of demographic inference based on the distribution of pairwise genetic differences between individuals (mismatch distribution) to the case of linked microsatellite data. Population genetics theory describes the distribution of mutations among a sample of genes under different demographic scenarios. However, the actual number of mutations can rarely be deduced from DNA polymorphisms. The inclusion of mutation models in theoretical predictions can improve the performance of statistical methods. We have developed a maximum-pseudolikelihood estimator for the parameters that characterize a demographic expansion for a series of linked loci evolving under a stepwise mutation model. Those loci would correspond to DNA polymorphisms of linked microsatellites (such as those found on the Y chromosome or the chloroplast genome). The proposed method was evaluated with simulated data sets and with a data set of chloroplast microsatellites that showed signal for demographic expansion in a previous study. The results show that inclusion of a mutational model in the analysis improves the estimates of the age of expansion in the case of older expansions.

Proteasome, transporter associated with antigen processing, and class I genes in the nurse shark Ginglymostoma cirratum: evidence for a stable class I region and MHC haplotype lineages.

PubMed

Ohta, Yuko; McKinney, E Churchill; Criscitiello, Michael F; Flajnik, Martin F

2002-01-15

Cartilaginous fish (e.g., sharks) are derived from the oldest vertebrate ancestor having an adaptive immune system, and thus are key models for examining MHC evolution. Previously, family studies in two shark species showed that classical class I (UAA) and class II genes are genetically linked. In this study, we show that proteasome genes LMP2 and LMP7, shark-specific LMP7-like, and the TAP1/2 genes are linked to class I/II. Functional LMP7 and LMP7-like genes, as well as multiple LMP2 genes or gene fragments, are found only in some sharks, suggesting that different sets of peptides might be generated depending upon inherited MHC haplotypes. Cosmid clones bearing the MHC-linked classical class I genes were isolated and shown to contain proteasome gene fragments. A non-MHC-linked LMP7 gene also was identified on another cosmid, but only two exons of this gene were detected, closely linked to a class I pseudogene (UAA-NC2); this region probably resulted from a recent duplication and translocation from the functional MHC. Tight linkage of proteasome and class I genes, in comparison with gene organizations of other vertebrates, suggests a primordial MHC organization. Another nonclassical class I gene (UAA-NC1) was detected that is linked neither to MHC nor to UAA-NC2; its high level of sequence similarity to UAA suggests that UAA-NC1 also was recently derived from UAA and translocated from MHC. These data further support the principle of a primordial class I region with few class I genes. Finally, multiple paternities in one family were demonstrated, with potential segregation distortions.

Identification of O-Linked Glycoproteins Binding to the Lectin Helix pomatia Agglutinin as Markers of Metastatic Colorectal Cancer.

PubMed

Peiris, Diluka; Ossondo, Marlène; Fry, Simon; Loizidou, Marilena; Smith-Ravin, Juliette; Dwek, Miriam V

2015-01-01

Protein glycosylation is an important post-translational modification shown to be altered in all tumour types studied to date. Mucin glycoproteins have been established as important carriers of O-linked glycans but other glycoproteins exhibiting altered glycosylation repertoires have yet to be identified but offer potential as biomarkers for metastatic cancer. In this study a glycoproteomic approach was used to identify glycoproteins exhibiting alterations in glycosylation in colorectal cancer and to evaluate the changes in O-linked glycosylation in the context of the p53 and KRAS (codon 12/13) mutation status. Affinity purification with the carbohydrate binding protein from Helix pomatia agglutinin (HPA) was coupled to 2-dimensional gel electrophoresis with mass spectrometry to enable the identification of low abundance O-linked glycoproteins from human colorectal cancer specimens. Aberrant O-linked glycosylation was observed to be an early event that occurred irrespective of the p53 and KRAS status and correlating with metastatic colorectal cancer. Affinity purification using the lectin HPA followed by proteomic analysis revealed annexin 4, annexin 5 and CLCA1 to be increased in the metastatic colorectal cancer specimens. The results were validated using a further independent set of specimens and this showed a significant association between the staining score for annexin 4 and HPA and the time to metastasis; independently (annexin A4: Chi square 11.45, P = 0.0007; HPA: Chi square 9.065, P = 0.0026) and in combination (annexin 4 and HPA combined: Chi square 13.47; P = 0.0002). Glycoproteins showing changes in O-linked glycosylation in metastatic colorectal cancer have been identified. The glycosylation changes were independent of p53 and KRAS status. These proteins offer potential for further exploration as biomarkers and potential targets for metastatic colorectal cancer.

Structural characterization of human general transcription factor TFIIF in solution

PubMed Central

Akashi, Satoko; Nagakura, Shinjiro; Yamamoto, Seiji; Okuda, Masahiko; Ohkuma, Yoshiaki; Nishimura, Yoshifumi

2008-01-01

Human general transcription factor IIF (TFIIF), a component of the transcription pre-initiation complex (PIC) associated with RNA polymerase II (Pol II), was characterized by size-exclusion chromatography (SEC), electrospray ionization mass spectrometry (ESI-MS), and chemical cross-linking. Recombinant TFIIF, composed of an equimolar ratio of α and β subunits, was bacterially expressed, purified to homogeneity, and found to have a transcription activity similar to a natural one in the human in vitro transcription system. SEC of purified TFIIF, as previously reported, suggested that this protein has a size >200 kDa. In contrast, ESI-MS of the purified sample gave a molecular size of 87 kDa, indicating that TFIIF is an αβ heterodimer, which was confirmed by matrix-assisted laser desorption/ionization (MALDI) MS of the cross-linked TFIIF components. Recent electron microscopy (EM) and photo-cross-linking studies showed that the yeast TFIIF homolog containing Tfg1 and Tfg2, corresponding to the human α and β subunits, exists as a heterodimer in the PIC, so the human TFIIF is also likely to exist as a heterodimer even in the PIC. In the yeast PIC, EM and photo-cross-linking studies showed different results for the mutual location of TFIIE and TFIIF along DNA. We have examined the direct interaction between human TFIIF and TFIIE by ESI-MS, SEC, and chemical cross-linking; however, no direct interaction was observed, at least in solution. This is consistent with the previous photo-cross-linking observation that TFIIF and TFIIE flank DNA separately on both sides of the Pol II central cleft in the yeast PIC. PMID:18218714

Link prediction measures considering different neighbors’ effects and application in social networks

NASA Astrophysics Data System (ADS)

Luo, Peng; Wu, Chong; Li, Yongli

Link prediction measures have been attracted particular attention in the field of mathematical physics. In this paper, we consider the different effects of neighbors in link prediction and focus on four different situations: only consider the individual’s own effects; consider the effects of individual, neighbors and neighbors’ neighbors; consider the effects of individual, neighbors, neighbors’ neighbors, neighbors’ neighbors’ neighbors and neighbors’ neighbors’ neighbors’ neighbors; consider the whole network participants’ effects. Then, according to the four situations, we present our link prediction models which also take the effects of social characteristics into consideration. An artificial network is adopted to illustrate the parameter estimation based on logistic regression. Furthermore, we compare our methods with the some other link prediction methods (LPMs) to examine the validity of our proposed model in online social networks. The results show the superior of our proposed link prediction methods compared with others. In the application part, our models are applied to study the social network evolution and used to recommend friends and cooperators in social networks.

A Bayesian model for estimating population means using a link-tracing sampling design.

PubMed

St Clair, Katherine; O'Connell, Daniel

2012-03-01

Link-tracing sampling designs can be used to study human populations that contain "hidden" groups who tend to be linked together by a common social trait. These links can be used to increase the sampling intensity of a hidden domain by tracing links from individuals selected in an initial wave of sampling to additional domain members. Chow and Thompson (2003, Survey Methodology 29, 197-205) derived a Bayesian model to estimate the size or proportion of individuals in the hidden population for certain link-tracing designs. We propose an addition to their model that will allow for the modeling of a quantitative response. We assess properties of our model using a constructed population and a real population of at-risk individuals, both of which contain two domains of hidden and nonhidden individuals. Our results show that our model can produce good point and interval estimates of the population mean and domain means when our population assumptions are satisfied. © 2011, The International Biometric Society.

Cross-linked compared with historical polyethylene in THA: an 8-year clinical study.

PubMed

Geerdink, Carel H; Grimm, Bernd; Vencken, Wendy; Heyligers, Ide C; Tonino, Alphons J

2009-04-01

Wear particle-induced osteolysis is a major cause of aseptic loosening in THA. Increasing wear resistance of polyethylene (PE) occurs by increasing the cross-link density and early reports document low wear rates with such implants. To confirm longer-term reductions in wear we compared cross-linked polyethylene (irradiation in nitrogen, annealing) with historical polyethylene (irradiation in air) in a prospective, randomized clinical study involving 48 patients who underwent THAs with a minimum followup of 7 years (mean, 8 years; range, 7-9 years). The insert material was the only variable. The Harris hip score, radiographic signs of osteolysis, and polyethylene wear were recorded annually. Twenty-three historical and 17 moderately cross-linked polyethylene inserts were analyzed (five patients died, three were lost to followup). At 8 years, the wear rate was lower for cross-linked polyethylene (0.088 +/- 0.03 mm/year) than for the historical polyethylene (0.142 +/- 0.07 mm/year). This reduction (38%) did not diminish with time (33% at 5 years). Acetabular cyst formation was less frequent (39% versus 12%), affected fewer DeLee and Charnley zones (17% versus 4%), and was less severe for the cross-linked polyethylene. The only revision was for an aseptically loose cup in the historical polyethylene group. Moderately cross-linked polyethylene maintained its wear advantage with time and produced less osteolysis, showing no signs of aging at mid-term followup. Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Developing and physicochemical evaluation of cross-linked electrospun gelatin-glycerol nanofibrous membranes for medical applications

NASA Astrophysics Data System (ADS)

Morsy, Reda; Hosny, Marwa; Reicha, Fikry; Elnimr, Tarek

2017-05-01

This study aims to develop optimal cross-linked electrospun gelatin-glycerol (GEL-GLY) nano-fibrous mats suitable for tissue engineering and wound dressing applications. The optimized procedure involves heating the gelatin and gelatin-glycerol solutions up to 90 °C. The electrospinning process was performed, followed by further cross-linking of electrospun films in a container containing glutaraldehyde (GTA) vapor. The results of X-ray diffraction (XRD), Fourier transformed infrared (FTIR), and Differential thermal analysis (DTA) confirmed that heating gelatin solution up to 90 °C in the presence of glycerol affected the cross-linking efficiency and interactions between GTA molecules and gelatin chains. Scanning Electron Microscope (SEM) analysis showed that GEL-GLY nano-fibrous mats with weight ratios less than or equal (12:3 w/w) exhibited a regular morphology with defect free in addition to increasing the degradation time, cross-linking efficiency, and swelling degree of electrospun gelatin/glycerol.

Model studies of diffusion-controlled (2-hydroxyethyl methacrylate) HEMA hydrogel membranes for controlled release of proteins

NASA Astrophysics Data System (ADS)

Appawu, Jennifer A. M.

This thesis project consisted of three main components that were connected by roots in chemical analysis for studies in tissue engineering. The first part focused on characterizing the structural parameters of synthetic cross-linked poly (2-hydroxyethyl methacrylate) (Poly(HEMA) hydrogel membranes to determine optimal formulations for clinical studies. Poly(HEMA) membranes were loaded with Keratincocyte Growth Factor (KGF) for controlled release studies. Protein loading and release kinetics were determined with fluorescence spectroscopy. The spatial distribution of a protein in the membrane was determined using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The last part of the project focused on determining the biological effects of the polymer membranes in-vitro with a model cell line and a pilot in-vivo animal study. Based on the components completed in this project, five chapters are included in this dissertation document and are summarized below. A new protocol was developed using fluorescence spectroscopy that measured the rate of protein diffusion into cross-linked polymer membranes by measuring the change in the fluorescence intensity of the protein solution. This technique was also able to detect a conformational change that occurs within protein when KGF was imbibed within these cross-linked polymer membranes. ToF-SIMS chemical imaging and 3D depth profiling was used to determine the spatial distribution of KGF protein in frozen-hydrated HEMA hydrogel membranes. The 3D depth profiles showed that the KGF protein was aggregated in bright spots that indicated that KGF was not spatially homogenous on the surface and through the depth profiles. 3D depth profiles of the membranes studied at various times during release studies show that areas with aggregated proteins were retained during release, and at times with maximum release. The interpretation of the bright regions is that the KGf protein interacted with the cross-linked network of the hydrogel membranes, making it not available for release. The in-vitro biological experiments with the HaCaT cell line showed that the HEMA hydrogels were capable of sustaining cell viability, proliferation, and adhesion through cell adhesion and wounding experiments. The pilot in-vivo animal study also revealed that KGF protein had retained its pharmacological activity. The study also showed that the KGF protein enhanced the rate of wound closure.

Using link analysis to explore the impact of the physical environment on pharmacist tasks.

PubMed

Lester, Corey A; Chui, Michelle A

2016-01-01

National community pharmacy organizations have been redesigning pharmacies to better facilitate direct patient care. However, evidence suggests that changing the physical layout of a pharmacy prior to understanding how the environment impacts pharmacists' work may not achieve the desired benefits. This study describes an objective method to understanding how the physical layout of the pharmacy may affect how pharmacists perform tasks. Link analysis is a systems engineering method used to describe the influence of the physical environment on task completion. This study used a secondary data set of field notes collected from 9 h of direct observation in one mass-merchandise community pharmacy in the U.S. State, Wisconsin. A node is an individual location in the environment. A link is the movement between two nodes. Tasks were inventoried and task themes identified. The mean, minimum, and maximum number of links needed to complete each task were then determined and used to construct a link table. A link diagram is a graphical display showing the links in conjunction with the physical layout of the pharmacy. A total of 92 unique tasks were identified resulting in 221 links. Tasks were sorted into five themes: patient care activities, insurance issues, verifying prescriptions, filling prescriptions, and other. Insurance issues required the greatest number of links with a mean of 4.75. Verifying prescriptions and performing patient care were the most commonly performed tasks with 36 and 30 unique task occurrences, respectively. Link analysis provides an objective method for identifying how a pharmacist interacts with the physical environment to complete tasks. This method provides designers with useful information to target interventions to improve the effectiveness of pharmacist work. Analysis beyond link analysis should be considered for large scale system redesign. Copyright © 2015 Elsevier Inc. All rights reserved.

Correlation between connexin 32 gene mutations and clinical phenotype in X-linked dominant Charcot-Marie-Tooth neuropathy

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

Ionasescu, V.; Ionasescu, R.; Searby, C.

1996-06-14

We studied the relationship between the genotype and clinical phenotype in 27 families with dominant X-linked Charcot-Marie-Tooth (CMTX1) neuropathy. Twenty-two families showed mutations in the coding region of the connexin32 (cx32) gene. The mutations include four nonsense mutations, eight missense mutations, two medium size deletions, and one insertion. Most missense mutations showed a mild clinical phenotype (five out of eight), whereas all nonsense mutations, the larger of the two deletions, and the insertion that produced frameshifts showed severe phenotypes. Five CMTX1 families with mild clinical phenotype showed no point mutations of the cx32 gene coding region. Three of these familiesmore » showed positive genetic linkage with the markers of the Xq13.1 region. The genetic linkage of the remaining two families could not be evaluated because of their small size. 25 refs., 1 fig., 1 tab.« less

CUL4B ubiquitin ligase in mouse development: a model for human X-linked mental retardation syndrome?

PubMed

Zhao, Yongchao; Sun, Yi

2012-08-01

CUL4B, a member of the cullin-RING ubiquitin ligase family, is frequently mutated in X-linked mental retardation (XLMR) patients. The study by Liu et al. showed that Cul4b plays an essential developmental role in the extra-embryonic tissues, while it is dispensable in the embryo proper during mouse embryogenesis. Viable Cul4b-null mice provide the first animal model to study neuronal and behavioral deficiencies seen in human CUL4B XLMR patients.

Peripheral inflammation and cognitive aging.

PubMed

Lim, Alvin; Krajina, Katarina; Marsland, Anna L

2013-01-01

Evidence suggests that inflammation, an innate immune response facilitating recovery from injury and pathogenic invasion, is positively associated with age-related cognitive decline and may play a role in risk for dementia. Physiological pathways linking the peripheral immune and central nervous systems are outlined, and studies linking inflammation with neurocognitive function are overviewed. We also present recent studies from our laboratory showing that midlife inflammation is related to cognitive function and brain morphology. Finally, potential implications for treatment, future directions, and limitations are discussed. Copyright © 2013 S. Karger AG, Basel.

[Effects of prevention education on Human Papillomavirus linked to cervix cancer for unmarried female university students].

PubMed

Kim, Hae Won

2009-08-01

This study was done to identify the effects of a Human Papillomavirus (HPV) linked to cervix cancer prevention education program for unmarried university female students. A new model in the cervix cancer prevention is provided. The research design was a nonequivalent control group pretest-posttest design. Participants were 63 female students in one of two university in an experimental group (29 students) and control group (34 students). After 4 weeks education, the differences between the two groups in the measurement variables were compared. Twelve weeks later, a follow-up test was done for experimental group only. After the education, experimental group showed significantly higher scores in all variables, the intention for Pap test (Z=-3.73, p<.001), intention for HPV vaccination (Z=-3.14, p=.002), general cancer prevention behavior (Z=-2.20, p=.028), attitudes to Pap (Z=-3.23, p=.001), benefits of cancer prevention behavior (Z=-3.97, p<.001), and HPV linked to cervix cancer knowledge (Z=-5.40, p<.001). In the follow-up study, the experimental group showed intermediate effects in intention for Pap test, intention of HPV vaccination and HPV linked to cervix cancer knowledge as well as short term effects in general cancer prevention behavior, attitudes to Pap and benefits of cancer prevention behavior. The program developed for this study on prevention education of HPV linked to cervix cancer was effective for unmarried university students in the short term and intermediate duration. Other educational approaches should be developed and short term effects and longitudinal changes of the education should be assessed. This education program should also be replicated for other female groups including unmarried working women or female adolescents.

In vitro response of retinal pigment epithelial cells exposed to chitosan materials prepared with different cross-linkers.

PubMed

Lai, Jui-Yang; Li, Ya-Ting; Wang, Tsu-Pin

2010-01-01

The interaction between cells and biopolymers is the evaluation indicator of the biocompatibility of materials. The purpose of this work was to examine the responses of retinal pigment epithelial (RPE) cells to genipin (GP) or glutaraldehyde (GTA) cross-linked chitosan by means of cell viability assays, cytokine expression analyses, and apoptosis assays. Evaluations of non-cross-linked chitosan were conducted simultaneously for comparison. Both GP and GTA treated samples with the same extent of cross-linking (around 80%) were prepared by varying cross-linking time. Our results showed that GP cross-linking was carried out by either radical polymerization of the monomers or S(N)2 nucleophilic substitution reaction involving the replacement of the ester group on the monomer with a secondary amide linkage. On the other hand, GTA could react with free amino groups of chitosan, leading to the formation of either the Schiff bases or the Michael-type adducts with terminal aldehydes. The biocompatibility of non-cross-linked chitosan membranes was demonstrated by the absence of any signs of toxicity or inflammation reaction. The present study showed that the ARPE-19 cells exposed to GTA cross-linked chitosan membranes had significantly higher cytotoxicity, interleukin-6 levels, and number of TUNEL-positive nuclei than did those exposed to GP treated samples. In addition, the materials modified with GTA trigger apoptosis at an early stage and may induce toxicity in the RPE cells later. The findings suggest that while the chitosan molecules bridged by GP are satisfactorily cytocompatible, the counterparts treated by GTA do not seem to be tolerated. In terms of material safety, the GP cross-linked chitosan may be compatible with human RPE cells and may have a potential application as delivery carriers in the treatment of posterior segment diseases.

MULTIMODAL IMAGING OF MOSAIC RETINOPATHY IN CARRIERS OF HEREDITARY X-LINKED RECESSIVE DISEASES.

PubMed

Wu, An-Lun; Wang, Jung-Pan; Tseng, Yun-Ju; Liu, Laura; Kang, Yu-Chuan; Chen, Kuan-Jen; Chao, An-Ning; Yeh, Lung-Kun; Chen, Tun-Lu; Hwang, Yih-Shiou; Wu, Wei-Chi; Lai, Chi-Chun; Wang, Nan-Kai

2018-05-01

To investigate the clinical features in carriers of X-linked retinitis pigmentosa, X-linked ocular albinism, and choroideremia (CHM) using multimodal imaging and to assess their diagnostic value in these three mosaic retinopathies. We prospectively examined 14 carriers of 3 X-linked recessive disorders (X-linked retinitis pigmentosa, X-linked ocular albinism, and CHM). Details of abnormalities of retinal morphology were evaluated using fundus photography, fundus autofluorescence (FAF) imaging, and spectral domain optical coherence tomography. In six X-linked retinitis pigmentosa carriers, fundus appearance varied from unremarkable to the presence of tapetal-like reflex and pigmentary changes. On FAF imaging, all carriers exhibited a bright radial reflex against a dark background. By spectral domain optical coherence tomography, loss of the ellipsoid zone in the macula was observed in 3 carriers (50%). Regarding the retinal laminar architecture, 4 carriers (66.7%) showed thinning of the outer nuclear layer and a dentate appearance of the outer plexiform layer. All five X-linked ocular albinism carriers showed a characteristic mud-splatter patterned fundus, dark radial streaks against a bright background on FAF imaging, and a normal-appearing retinal structure by spectral domain optical coherence tomography imaging. Two of the 3 CHM carriers (66.7%) showed a diffuse moth-eaten appearance of the fundus, and all 3 showed irregular hyper-FAF and hypo-FAF spots throughout the affected area. In the CHM carriers, the structural changes observed by spectral domain optical coherence tomography imaging were variable. Our findings in an Asian cohort suggest that FAF imaging is a practical diagnostic test for differentiating X-linked retinitis pigmentosa, X-linked ocular albinism, and CHM carriers. Wide-field FAF is an easy and helpful adjunct to testing for the correct diagnosis and identification of lyonization in carriers of these three mosaic retinopathies.

O-Glycosylation in Cell Wall Proteins in Scedosporium prolificans Is Critical for Phagocytosis and Inflammatory Cytokines Production by Macrophages

PubMed Central

Xisto, Mariana I. D. S.; Bittencourt, Vera C. B.; Liporagi-Lopes, Livia Cristina; Haido, Rosa M. T.; Mendonça, Morena S. A.; Sassaki, Guilherme; Figueiredo, Rodrigo T.; Romanos, Maria Teresa V.; Barreto-Bergter, Eliana

2015-01-01

In this study, we analyze the importance of O-linked oligosaccharides present in peptidorhamnomannan (PRM) from the cell wall of the fungus Scedosporium prolificans for recognition and phagocytosis of conidia by macrophages. Adding PRM led to a dose-dependent inhibition of conidia phagocytosis, whereas de-O-glycosylated PRM did not show any effect. PRM induced the release of macrophage-derived antimicrobial compounds. However, O-linked oligosaccharides do not appear to be required for such induction. The effect of PRM on conidia-induced macrophage killing was examined using latex beads coated with PRM or de-O-glycosylated PRM. A decrease in macrophage viability similar to that caused by conidia was detected. However, macrophage killing was unaffected when beads coated with de-O-glycosylated PRM were used, indicating the toxic effect of O-linked oligosaccharides on macrophages. In addition, PRM triggered TNF-α release by macrophages. Chemical removal of O-linked oligosaccharides from PRM abolished cytokine induction, suggesting that the O-linked oligosaccharidic chains are important moieties involved in inflammatory responses through the induction of TNF-α secretion. In summary, we show that O-glycosylation plays a role in the recognition and uptake of S. prolificans by macrophages, killing of macrophages and production of pro- inflammatory cytokines. PMID:25875427

Mocaf cross-linking with gluten to improve the quality of mocaf dough

NASA Astrophysics Data System (ADS)

Raharja, Sapta; Udin, Faqih; Suparno, Ono; Febrianti, Faricha Helfi; Nuraisyah, Ani

2017-03-01

Crosslink between mocaf and gluten is conducted to increase the using of mocaf which has very big potential in Indonesia. The effort of cross-linking between mocaf and gluten is to get mocaf flour with better dough quality. This study aims to produce a cross-linked mocaf-gluten flour and to evaluate the influence of heating temperature (X1) and the addition of gluten concentration (X2) using completely randomized design factorial (RAFL). The cross-linking is carried out in alkaline solution with 10%, 20%, and 30% gluten addition and heating temperature at 50, 55, and 60 °C. The result showed that mocaf - gluten flour with the treatment of 30% gluten addition at 55 °C had the largest amount of protein and baking expansion (i.e 19.77% and 2.78 mL/g). Swelling power of the flour was increasing along with the increasing of water absorbing capacity of the mocaf - gluten flour. Birefringence properties of mocaf - gluten flour tended to be reduced as the increasing heating temperature. FTIR analysis of mocaf - gluten flour showed that there was peak strengthening of the infrared spectrum of the C - N bond at 1167-1159 cm-1 which was presumably resulted from the gluten addition and the cross-linking properties.

Evaluation of disintegrants functionality for orodispersible mini tablets.

PubMed

Soulairol, Ian; Chaheen, Mohammad; Tarlier, Nicolas; Aubert, Adrien; Bataille, Bernard; Sharkawi, Tahmer

2017-11-01

This work evaluates the functionalities of different superdisintegrants (SD) for manufacturing orodispersible mini tablets (ODMT) by direct compression. Twenty-three formulations varying in SD type, concentration, and lubricant were used to manufacture ODMT. The ODMT were then characterized for the following properties: friability, porosity, tensile strength, in vivo and in vitro disintegration time (DT). The results show that the presence, type, and concentration of SD did not influence friability, porosity, or tablet tensile strength. With regards to in vivo DT, only cross-linked poly (vinyl pyrrolidone) improved DT in all the tested formulations. Results also showed that when using microcrystalline cellulose (MCC) above 20% in the formulation, DT is longer. Cross-linked carboxymethyl cellulose accelerates DT when the MCC content is less than 20%. As for cross-linked carboxymethyl starch and calcium alginate showed no improvement on DT. Results for in vitro DT were all shorter than in vivo results and there was no correlation with the in vivo evaluation. This study shows that there is a need to develop better in vitro testing that precisely simulates in vivo conditions and that are adapted to ODMT. This standardization of the test methods for ODMTs must be accompanied by an improvement in the comprehension of SD mechanisms.

Low-Temperature Cross-Linking of PEDOT:PSS Films Using Divinylsulfone.

PubMed

Mantione, Daniele; Del Agua, Isabel; Schaafsma, Wandert; ElMahmoudy, Mohammed; Uguz, Ilke; Sanchez-Sanchez, Ana; Sardon, Haritz; Castro, Begoña; Malliaras, George G; Mecerreyes, David

2017-05-31

Recent interest in bioelectronics has prompted the exploration of properties of conducting polymer films at the interface with biological milieus. Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) from a commercially available source has been used as a model system for these studies. Different cross-linking schemes have been used to stabilize films of this material against delamination and redispersion, but the cost is a decrease in the electrical conductivity and/or additional heat treatment. Here we introduce divinylsulfone (DVS) as a new cross-linker for PEDOT:PSS. Thanks to the higher reactiveness of the vinyl groups of DVS, the cross-linking can be performed at room temperature. In addition, DVS does not reduce electronic conductivity of PEDOT:PSS but rather increases it by acting as a secondary dopant. Cell culture studies show that PEDOT:PSS:DVS films are cytocompatible and support neuroregeneration. As an example, we showed that this material improved the transconductance value and stability of an organic electrochemical transistor (OECT) device. These results open the way for the utilization of DVS as an effective cross-linker for PEDOT:PSS in bioelectronics applications.

MLR-1023 is a potent and selective allosteric activator of Lyn kinase in vitro that improves glucose tolerance in vivo.

PubMed

Saporito, Michael S; Ochman, Alexander R; Lipinski, Christopher A; Handler, Jeffrey A; Reaume, Andrew G

2012-07-01

2(1H)-pyrimidinone,5-(3-methylphenoxy) (MLR-1023) is a candidate for the treatment of type 2 diabetes. The current studies were aimed at determining the mechanism by which MLR-1023 mediates glycemic control. In these studies, we showed that MLR-1023 reduced blood glucose levels without increasing insulin secretion in vivo. We have further determined that MLR-1023 did not activate peroxisome proliferator-activated α, δ, and γ receptors or glucagon-like peptide-1 receptors or inhibit dipeptidyl peptidase-4 or α-glucosidase enzyme activity. However, in an in vitro broad kinase screen MLR-1023 activated the nonreceptor-linked Src-related tyrosine kinase Lyn. MLR-1023 increased the V(max) of Lyn with an EC(50) of 63 nM. This Lyn kinase activation was ATP binding site independent, indicating that MLR-1023 regulated the kinase through an allosteric mechanism. We have established a link between Lyn activation and blood glucose lowering with studies showing that the glucose-lowering effects of MLR-1023 were abolished in Lyn knockout mice, consistent with existing literature linking Lyn kinase and the insulin-signaling pathway. In summary, these studies describe MLR-1023 as a unique blood glucose-lowering agent and show that MLR-1023-mediated blood glucose lowering depends on Lyn kinase activity. These results, coupled with other results (J Pharmacol Exp Ther 342:23-32, 2012), suggest that MLR-1023 and Lyn kinase activation may be a new treatment modality for type 2 diabetes.

Rumination, distraction and mindful self-focus: effects on mood, dysfunctional attitudes and cortisol stress response.

PubMed

Kuehner, C; Huffziger, S; Liebsch, K

2009-02-01

Although aggravating effects of rumination on dysfunctional cognitions and endocrine stress responses have been proposed, experimental studies testing these assumptions are lacking. In parallel, mindfulness theory suggests beneficial effects of mindfulness on dysfunctional cognitions. This study aimed to investigate the effects of induced rumination, distraction and mindful self-focus on mood and dysfunctional attitudes and to assess the possible impact of induced rumination on participants' cortisol responses. Sixty university students were subjected to negative mood induction and subsequently randomly assigned to a rumination, distraction or mindful self-focus condition. The latter included statements focusing on self-acceptance and awareness of the breath. Four saliva cortisol samples were selected during the session. Compared to induced rumination, distraction showed a clear beneficial effect on the course of dysphoric mood, whereas a mindful self-focus did not. In contrast to distraction and mindful self-focus, participants induced to ruminate showed significant increases in dysfunctional attitudes from baseline to post-induction. Although rumination was not itself linked to higher cortisol responses, participants scoring high on the Beck Depression Inventory (BDI)-II who were induced to ruminate showed a smaller decrease in cortisol levels than those scoring low on the BDI-II. This study indicates that rumination as a dysfunctional mode of cognitive processing is able to maintain depression-linked dysfunctional thought content. Furthermore, our study revealed preliminary indications for a link between induced rumination and the cortisol stress response in vulnerable individuals.

Immunoglobulin subunits of murine B lymphocytes: structure and associations with other membrane proteins.

PubMed Central

Vogel, L; Haustein, D

1989-01-01

The Ig subunit structure of murine B lymphocytes was studied by employing different radiolabelling techniques in combination with chemical cross-linking. The main membrane structure of IgM was a half molecule that was disulphide-linked to proteins with MW 30,000, 45,000 and 55,000, respectively. Small amounts of mu 2L2, microL disulphide-linked to a protein with MW 50,000, and free microL were also detected. The main IgD structures were half molecules disulphide-linked to two proteins with MW 14,000 and two proteins with MW 16,000. Furthermore, IgD half molecules disulphide-linked to a protein with MW 16,000 and free half molecules could be demonstrated. Labelling with hydrophobic reagents showed that all Ig molecules and the protein with MW 50,000, linked to microL, penetrated the lipid bilayer, whereas the other IgM- and IgD-linked proteins probably did not. Additional proteins which were associated exclusively with IgM were detected by chemical cross-linking. These findings offer new possibilities for the investigation of the function(s) of antigen receptors on B cells. Images Figure 1 Figure 2 Figure 4 Figure 5 PMID:2787780

Non-iterative geometric approach for inverse kinematics of redundant lead-module in a radiosurgical snake-like robot.

PubMed

Omisore, Olatunji Mumini; Han, Shipeng; Ren, Lingxue; Zhang, Nannan; Ivanov, Kamen; Elazab, Ahmed; Wang, Lei

2017-08-01

Snake-like robot is an emerging form of serial-link manipulator with the morphologic design of biological snakes. The redundant robot can be used to assist medical experts in accessing internal organs with minimal or no invasion. Several snake-like robotic designs have been proposed for minimal invasive surgery, however, the few that were developed are yet to be fully explored for clinical procedures. This is due to lack of capability for full-fledged spatial navigation. In rare cases where such snake-like designs are spatially flexible, there exists no inverse kinematics (IK) solution with both precise control and fast response. In this study, we proposed a non-iterative geometric method for solving IK of lead-module of a snake-like robot designed for therapy or ablation of abdominal tumors. The proposed method is aimed at providing accurate and fast IK solution for given target points in the robot's workspace. n-1 virtual points (VPs) were geometrically computed and set as coordinates of intermediary joints in an n-link module. Suitable joint angles that can place the end-effector at given target points were then computed by vectorizing coordinates of the VPs, in addition to coordinates of the base point, target point, and tip of the first link in its default pose. The proposed method is applied to solve IK of two-link and redundant four-link modules. Both two-link and four-link modules were simulated with Robotics Toolbox in Matlab 8.3 (R2014a). Implementation result shows that the proposed method can solve IK of the spatially flexible robot with minimal error values. Furthermore, analyses of results from both modules show that the geometric method can reach 99.21 and 88.61% of points in their workspaces, respectively, with an error threshold of 1 mm. The proposed method is non-iterative and has a maximum execution time of 0.009 s. This paper focuses on solving IK problem of a spatially flexible robot which is part of a developmental project for abdominal surgery through minimal invasion or natural orifices. The study showed that the proposed geometric method can resolve IK of the snake-like robot with negligible error offset. Evaluation against well-known methods shows that the proposed method can reach several points in the robot's workspace with high accuracy and shorter computational time, simultaneously.

Effective oral delivery of insulin in animal models using vitamin B12-coated dextran nanoparticles.

PubMed

Chalasani, Kishore B; Russell-Jones, Gregory J; Jain, Akhlesh K; Diwan, Prakash V; Jain, Sanjay K

2007-09-26

The potential utility of vitamin B12 carrier system for the oral delivery of conjugated peptides/proteins and enhancement of nanoparticles (NPs) transport has been demonstrated. The present study aims to optimize the effectiveness of VB12-NPs conjugates using different levels of cross-linking, linked with different VB(12)-coatings and evaluates in animal models to investigate an efficient insulin carrier. Amino alkyl VB12 derivatives suitable for oral delivery were synthesized at 5'hydoxy ribose and e-propionamide sites via carbamate and ester/amide linkages, and were coupled to succinic acid modified dextran NPs of varied cross-linking. VB12 binding was confirmed by XPS analysis, and was quantified by HPLC (4.0 to 5.7% w/w of NPs). These polydisperse NPs conjugates showed higher size, high insulin entrapment and faster insulin release with low levels of cross-linking. These VB12-NPs conjugates (150-300 nm) showed profound (70-75% blood glucose reductions) and prolonged (54 h) anti-diabetic effects with biphasic behaviour in STZ diabetic rats. NPs with the low levels of cross-linking were found to be superior carriers, and were more effective with VB12 derivatives of carbamate linkage. The pharmacological availability relative to SC insulin was found to be 29.4%, which was superior compared to NPs conjugate of ester linked VB12 (1.5 fold) and relatively higher cross-linked particles (1.1 fold). Further, the NPs carrier demonstrated a similar oral insulin efficacy in congenital diabetic mice (60% reduction at 20 h). Significant quantities of plasma insulin were found in both animal models (231 and 197 muIU/ml). At two investigated doses, the carrier system shows dose response. Pre-dosing with a large excess of free VB12 minimized the observed activity, indicating predominance of VB12 mediated uptake. It is concluded that VB12-dextran NPs conjugate is a viable carrier for peroral insulin delivery to treat diabetics.

Spectroscopic characterization of collagen cross-links in bone

NASA Technical Reports Server (NTRS)

Paschalis, E. P.; Verdelis, K.; Doty, S. B.; Boskey, A. L.; Mendelsohn, R.; Yamauchi, M.

2001-01-01

Collagen is the most abundant protein of the organic matrix in mineralizing tissues. One of its most critical properties is its cross-linking pattern. The intermolecular cross-linking provides the fibrillar matrices with mechanical properties such as tensile strength and viscoelasticity. In this study, Fourier transform infrared (FTIR) spectroscopy and FTIR imaging (FTIRI) analyses were performed in a series of biochemically characterized samples including purified collagen cross-linked peptides, demineralized bovine bone collagen from animals of different ages, collagen from vitamin B6-deficient chick homogenized bone and their age- and sex-matched controls, and histologically stained thin sections from normal human iliac crest biopsy specimens. One region of the FTIR spectrum of particular interest (the amide I spectral region) was resolved into its underlying components. Of these components, the relative percent area ratio of two subbands at approximately 1660 cm(-1) and approximately 1690 cm(-1) was related to collagen cross-links that are abundant in mineralized tissues (i.e., pyridinoline [Pyr] and dehydrodihydroxylysinonorleucine [deH-DHLNL]). This study shows that it is feasible to monitor Pyr and DHLNL collagen cross-links spatial distribution in mineralized tissues. The spectroscopic parameter established in this study may be used in FTIRI analyses, thus enabling the calculation of relative Pyr/DHLNL amounts in thin (approximately 5 microm) calcified tissue sections with a spatial resolution of approximately 7 microm.

Rain attenuation statistics over millimeter wave bands in South Korea

NASA Astrophysics Data System (ADS)

Shrestha, Sujan; Choi, Dong-You

2017-01-01

Rain induced degradations are significant for terrestrial microwave links operating at frequencies higher than 10 GHz. Paper presents analyses done on rain attenuation and rainfall data for three years between 2013 till 2015, in 3.2 km experimental link of 38 GHz and 0.1 km link at 75 GHz. The less link distance is maintained for 75 GHz operating frequency in order to have better recording of propagation effect as such attenuation induced by rain. OTT Parsivel is used for collection of rain rate database which show rain rate of about 50 mm/h and attenuation values of 20.89 and 28.55 dB are obtained at 0.01% of the time for vertical polarization under 38 and 75 GHz respectively. Prediction models, namely, ITU-R P. 530-16, Da Silva Mello, Moupfouma, Abdulrahman, Lin and differential equation approach are analyzed. This studies help to identify most suitable rain attenuation model for higher microwave bands. While applying ITU-R P. 530-16, the relative error margin of about 3%, 38% and 42% along with 80, 70, 61% were obtained in 0.1%, 0.01% and 0.001% of the time for vertical polarization under 38 and 75 GHz respectively. Interestingly, ITU-R P. 530-16 shows relatively closer estimation to measured rain attenuation at 75 GHz with relatively less error probabilities and additionally, Abdulrahman and ITU-R P. 530-16 results in better estimation to the measured rain attenuation at 38 GHz link. The performance of prominent rain attenuation models are judged with different error matrices as recommended by ITU-R P. 311-15. Furthermore, the efficacy of frequency scaling technique of rain attenuation between links distribution are also discussed. This study shall be useful for making good considerations in rain attenuation predictions for terrestrial link operating at higher frequencies.

A quantitative analysis of sensitivity to the conditioned reinforcing value of terminal-link stimuli in a concurrent-chains schedule.

PubMed Central

Omino, T

1993-01-01

Pigeons were exposed to a concurrent-chains schedule in which a single variable-interval 30-s schedule was used in the initial links and fixed-time schedules were used in the terminal links. Three types of keylight conditions were used in the terminal links. In the first condition, different delays were associated with different keylight stimuli (cued condition). In the second condition, different delays were associated with the same stimulus, either a blackout (uncued blackout condition) or a white key (uncued white condition). Paired values of terminal-link fixed-time schedules differed by a constant ratio of 3:1, while the absolute value of delays was varied from 3 s to 54 s. The results showed that choice proportions for the shorter of two delays increased when the absolute size of the delays was increased for all keylight conditions. Further, the choice proportions for the shorter delay increased from the uncued blackout condition, to the uncued white condition, to the cued condition. A modified version of Fantino's (1969) delay-reduction model (expressed as a function relating the response ratio to the delay-reduction ratio) can be applied to these data by showing that sensitivity to delay reduction increased from the uncued blackout condition, to the uncued white condition, to the cued condition. Thus, the present study demonstrated that a modified version of the delay-reduction model can be used to assess quantitative differences in the terminal-link keylight condition in terms of sensitivity to delay reduction (i.e., the conditioned reinforcing value of the terminal-link keylight stimuli). PMID:8283150

Linking social capital and mortality in the elderly: a Swedish national cohort study.

PubMed

Sundquist, Kristina; Hamano, Tsuyoshi; Li, Xinjun; Kawakami, Naomi; Shiwaku, Kuninori; Sundquist, Jan

2014-07-01

Our objective was to examine the association between neighborhood linking social capital (a concept describing the amount of trust between individuals and societal institutions) and all-cause and cause-specific mortality in the elderly. The entire Swedish population aged 65+, a total of 1,517,336 men and women, was followed from 1 January 2002 until death, emigration, or the end of the study on 31 December 2010. Small geographic units were used to define neighborhoods. The definition of linking social capital was based on neighborhood voting participation rates, categorized into three groups. Multilevel logistic regression was used to estimate odds ratios (ORs) and between-neighborhood variance in three different models. The results showed an overall association between linking social capital and all-cause mortality. The significant OR of 1.53 in the group with low linking social capital decreased, but remained significant (OR=1.27), after accounting for age, sex, family income, marital status, country of birth, education level, and region of residence. There were also significant associations between linking social capital and cause-specific mortality in coronary heart disease, psychiatric disorders, cancer, stroke, chronic lower respiratory diseases, type 2 diabetes, and suicide. There are associations between low linking social capital and mortality from chronic disorders and suicide in the elderly population. Community support for elderly people living in neighborhoods with low levels of linking social capital may need to be strengthened. Copyright © 2014 Elsevier Inc. All rights reserved.

Hodgkin's disease, work, and the environment. A review.

PubMed

McCunney, R J

1999-01-01

Hodgkin's disease (HD), a lymphoma with an annual incidence in the United States of approximately 7500 cases, primarily affects the lymph nodes, spleen, and liver. The point of this article is to critically review the literature regarding the purported relationships between HD, certain occupations, and exposure to chemical agents. Attention will also be focused on recent advances in molecular genetics in the etiology of this ailment. A MEDLINE search was conducted to assess case-control and mortality evaluations that investigated links between HD and certain occupations and exposure to designated hazards. A review of citations in the Silver Platter Occupational and Environmental Medicine CD-ROM database was also conducted to ensure that all pertinent reports were obtained. Of the industries evaluated, woodworking showed the most consistent link between an increased risk of HD (relative risk, 1.8 to 7.2), but not all studies conducted showed positive associations. Although certain chemicals (ie, chlorophenols, pesticides) were reported as risks, no chemical was consistently and unambiguously linked with HD. Recent investigative work, however, points to a major etiological role for the Epstein-Barr virus (EBV), genetic fragments of which have been noted in Reed-Sternberg cells, the classic malignant cells of HD. The occupation most consistently associated with HD appears to be woodworking, although no specific chemical has been consistently linked with this lymphoma. The most persuasive evidence regarding the cause of HD arises from recent studies, including epidemiological, clinical, and genetic studies, that point to a major role by the EBV.

Escape of X-linked miRNA genes from meiotic sex chromosome inactivation

PubMed Central

Sosa, Enrique; Flores, Luis; Yan, Wei; McCarrey, John R.

2015-01-01

Past studies have indicated that transcription of all X-linked genes is repressed by meiotic sex chromosome inactivation (MSCI) during the meiotic phase of spermatogenesis in mammals. However, more recent studies have shown an increase in steady-state levels of certain X-linked miRNAs in pachytene spermatocytes, suggesting that either synthesis of these miRNAs increases or that degradation of these miRNAs decreases dramatically in these cells. To distinguish between these possibilities, we performed RNA-FISH to detect nascent transcripts from multiple miRNA genes in various spermatogenic cell types. Our results show definitively that Type I X-linked miRNA genes are subject to MSCI, as are all or most X-linked mRNA genes, whereas Type II and III X-linked miRNA genes escape MSCI by continuing ongoing, active transcription in primary spermatocytes. We corroborated these results by co-localization of RNA-FISH signals with both a corresponding DNA-FISH signal and an immunofluorescence signal for RNA polymerase II. We also found that X-linked miRNA genes that escape MSCI locate non-randomly to the periphery of the XY body, whereas genes that are subject to MSCI remain located within the XY body in pachytene spermatocytes, suggesting that the mechanism of escape of X-linked miRNA genes from MSCI involves their relocation to a position outside of the repressive chromatin domain associated with the XY body. The fact that Type II and III X-linked miRNA genes escape MSCI suggests an immediacy of function of the encoded miRNAs specifically required during the meiotic stages of spermatogenesis. PMID:26395485

Developing and evaluating Quilts for the depiction of large layered graphs.

PubMed

Bae, Juhee; Watson, Ben

2011-12-01

Traditional layered graph depictions such as flow charts are in wide use. Yet as graphs grow more complex, these depictions can become difficult to understand. Quilts are matrix-based depictions for layered graphs designed to address this problem. In this research, we first improve Quilts by developing three design alternatives, and then compare the best of these alternatives to better-known node-link and matrix depictions. A primary weakness in Quilts is their depiction of skip links, links that do not simply connect to a succeeding layer. Therefore in our first study, we compare Quilts using color-only, text-only, and mixed (color and text) skip link depictions, finding that path finding with the color-only depiction is significantly slower and less accurate, and that in certain cases, the mixed depiction offers an advantage over the text-only depiction. In our second study, we compare Quilts using the mixed depiction to node-link diagrams and centered matrices. Overall results show that users can find paths through graphs significantly faster with Quilts (46.6 secs) than with node-link (58.3 secs) or matrix (71.2 secs) diagrams. This speed advantage is still greater in large graphs (e.g. in 200 node graphs, 55.4 secs vs. 71.1 secs for node-link and 84.2 secs for matrix depictions). © 2011 IEEE

Synthesis and properties of reprocessable sulfonated polyimides cross-linked via acid stimulation for use as proton exchange membranes

NASA Astrophysics Data System (ADS)

Zhang, Boping; Ni, Jiangpeng; Xiang, Xiongzhi; Wang, Lei; Chen, Yongming

2017-01-01

Cross-linked sulfonated polyimides are one of the most promising materials for proton exchange membrane (PEM) applications. However, these cross-linked membranes are difficult to reprocess because they are insoluble. In this study, a series of cross-linkable sulfonated polyimides with flexible pendant alkyl side chains containing trimethoxysilyl groups is successfully synthesized. The cross-linkable polymers are highly soluble in common solvents and can be used to prepare tough and smooth films. Before the cross-linking reaction is complete, the membranes can be reprocessed, and the recovery rate of the prepared films falls within an acceptable range. The cross-linked membranes are obtained rapidly when the cross-linkable membranes are immersed in an acid solution, yielding a cross-linking density of the gel fraction of greater than 90%. The cross-linked membranes exhibit high proton conductivities and tensile strengths under hydrous conditions. Compared with those of pristine membranes, the oxidative and hydrolytic stabilities of the cross-linked membranes are significantly higher. The CSPI-70 membrane shows considerable power density in a direct methanol fuel cell (DMFC) test. All of these results suggest that the prepared cross-linked membranes have great potential for applications in proton exchange membrane fuel cells.

Psychosocial work aspects, stress and musculoskeletal pain among musicians. A systematic review in search of correlates and predictors of playing-related pain.

PubMed

Jacukowicz, Aleksandra

2016-06-16

Musicians face numerous psychosocial and physical demands at work resulting in high prevalence of musculoskeletal problems. Unlike physical risks, little is known about psychosocial work factors influencing such health problems in this particular group. The paper aimed to identify psychosocial work demands resulting in musculoskeletal problems among musicians. A systematic review was undertaken to find data linking psychosocial work demands or stress with musculoskeletal disorders among musicians. The exploration of databases resulted in nine research studies linking psychosocial aspects of work or stress with musculoskeletal problems among musicians. The analyzed studies linked psychosocial aspects with musculoskeletal problems in three ways - showing proportions of people indicating particular causes of pain, indicating correlations between these variables or performing regression analysis showing psychosocial predictors of musculoskeletal pain. Only a few studies have undertaken the issue of psychosocial risk factors for musculoskeletal problems among musicians. The results revealed that some psychosocial aspects of work, e.g. long hours at work, work content, high job demands, low control/influence, lack of social support, were related to musculoskeletal pain, however, the methods and results were inconsistent. The extant studies employed variety of definitions of psychosocial aspects that hindered the possibility for consistent conclusions. Basing on those conclusions, future directions were offered.

Cross-Linking Studies of Lysozyme Nucleation

NASA Technical Reports Server (NTRS)

Forsythe, Elizabeth; Pusey, Marc

2000-01-01

Tetragonal chicken egg white crystals consist of 4(sub 3) helices running in alternating directions, the helix rows having a two fold symmetry with each other. The unit cell consists of one complete tetrameric turn from each of two adjacent helices (an octamer). PBC analysis indicates that the helix intermolecular bonds are the strongest in the crystal, therefore likely formed first. AFM analysis of the (110) surface shows only complete helices, no half steps or bisected helices being found, while AFM line scans to measure the growth step increments show that they are multiples of the 4(sub 3) helix tetramer dimensions. This supports our thesis that the growth units are in fact multiples of the four molecule 4(sub 3) helix unit, the "average" growth unit size for the (110) face being an octamer (two turns about the helix) and the (101) growth unit averaging about the size of a hexamer. In an effort to better understand the species involved in the crystal nucleation and growth process, we have initiated an experimental program to study the species formed in solution compared to what is found in the crystal through covalent cross-linking studies. These experiments use the heterobifunctional cross-linking agent aminoethyl-4-azidonitroanaline (AEANA). An aliphatic amine at one end is covalently attached to the protein by a carbodiimide-mediated reaction, and a photo reactive group at the other can be used to initiate crosslinking. Modifications to the parent structure can be used to alter the distance between the two reactive groups and thus the cross-linking agents "reach". In practice, the cross-linking agent is first coupled to the asp101 side chain through the amine group. Asp101 lies within the active site cleft, and previous work with fluorescent probes had shown that derivatives at this site still crystallize in the tetragonal space group. This was also found to be the case with the AEANA derivative, which gave red tetragonal crystals. The protein now has a reactive group that can be photoactivated at a specific point in the nucleation or crystal growth process to "capture" protein molecules bound within reach of the crosslinking agent. If those bound protein molecules have a defined geometric relationship with the capturing molecule, such as would be found in a crystal, then the photoreacted cross-linking site should be consistent. Random protein interactions, typical of an amorphous precipitate or interaction, would show a random cross-linking reaction. The results of these and other experiments will be presented.

Identification of erosional and inundation hazard zones in Ken-Betwa river linking area, India, using remote sensing and GIS.

PubMed

Avtar, Ram; Singh, Chander Kumar; Shashtri, Satayanarayan; Mukherjee, Saumitra

2011-11-01

Ken-Betwa river link is one of the pilot projects of the Inter Linking of Rivers program of Government of India in Bundelkhand Region. It will connect the Ken and Betwa rivers through a system of dams, reservoirs, and canals to provide storage for excess rainfall during the monsoon season and avoid floods. The main objective of this study is to identify erosional and inundation prone zones of Ken-Betwa river linking site in India using remote sensing and geographic information system tools. In this study, Landsat Thematic Mapper data of year 2005, digital elevation model from the Shuttle Radar Topographic Mission, and other ancillary data were analyzed to create various thematic maps viz. geomorphology, land use/land cover, NDVI, geology, soil, drainage density, elevation, slope, and rainfall. The integrated thematic maps were used for hazard zonation. This is based on categorizing the different hydrological and geomorphological processes influencing the inundation and erosion intensity. Result shows that the southern part of the study area which lies in Panna district of Madhya Pradesh, India, is more vulnerable than the other areas.

Evaluation of super-link system theory for spinal cord injury patients using participatory action research in a rehabilitation hospital.

PubMed

Chen, Hsiao-Yu; Wu, Tzu-Jung; Cheng, Mei-Li; Sung, Hsi-Hui

2012-01-01

The purpose of this study was to integrate and evaluate the spinal cord injury rehabilitation nursing theory named Super-Link System Theory using participatory action research. Data were collected from October 2007 to September 2008 in a rehabilitation hospital by means of interviews, participant observations, documentary resources, case conferences and reports, and participants' self-reflective inquiries. The Super-Link System Theory was introduced to 31 rehabilitation nurses. The nurses selected a key reference group including the researcher to facilitate the participatory action research process to implement and evaluate the theory. Data were analyzed using content analysis. The findings shows that several key concepts were clarified and specific nursing interventions were identified. Furthermore, an integrated link system from the hospital to the community through both rehabilitation nurses and discharge planners was established. The study demonstrated an evidence base for an evolving theory of care, and empowered nurses to make sustainable changes to their practice. © 2012 Association of Rehabilitation Nurses.

Biodegradation pattern and tissue integration of native and cross-linked porcine collagen soft tissue augmentation matrices – an experimental study in the rat

PubMed Central

2014-01-01

Introduction Within the last decades, collagen types I and III have been established as a sufficient biomaterial for GBR and GTR procedures. They might also be an adequate matrix for soft tissue augmentations. However, collagen materials differ significantly regarding resorption time, biodegradation pattern and the invasion of inflammatory cells. The aim of the present study was to compare the biodegradation and tissue integration of native, differently processed and cross-linked collagen scaffolds in rats. Methods Four experimental porcine collagen matrices of 1.0 mm thickness, developed for soft tissue augmentation procedures, were tested. Based on the same native dermal Type I and III collagen, native (ND, Mucoderm® prototype), specifically defatted (DD), ethylene dioxide cross-linked (ECL) and dehydrothermally cross-linked (DCL) dermis collagen (AAP/Botiss Biomaterials, Berlin, Germany) were evaluated. Two specimens of 1 × 1 cm were fixed around a non-absorbable spacer using non-absorbable sutures. After rehydration, specimens (N = 8) were randomly allocated in unconnected subcutaneous pouches on the back of 40 Wistar rats. Rats were divided into five groups (1, 2, 4, 8 and 12 weeks), including eight animals each. After each period, eight rats were sacrificed and explanted specimens were prepared for histological analysis. The following parameters were evaluated: membrane thickness as a sign of biodegradation and volume stability, cell ingrowth, vascularization, tissue integration and foreign body reaction. Results Biodegradation pattern of the non cross-linked collagen scaffolds differed only slightly in terms of presence of inflammatory cells and cell invasion into the matrix. In terms of biodegradation, ECL displayed a considerable slower resorption than ND, DCL and DD. Chemical cross-linking using ethylene dioxide showed a significant higher invasion of inflammatory cells. Conclusion Within the limits of the present study it was concluded that the processing techniques influenced the collagen properties in a different intensity. Dehydrothermal cross-linking and special defatting did not notably change the biodegradation pattern, whereas cross-linking using ethylene dioxide led to significant higher volume stability of the matrix. However, ECL showed an increased inflammatory response and compromised tissue integration. Therefore, ethylene dioxide seems to be not suitable for stabilization of collagen matrices for soft tissue augmentation procedures. PMID:24670219

Ultra-high vacuum surface analysis study of rhodopsin incorporation into supported lipid bilayers.

PubMed

Michel, Roger; Subramaniam, Varuni; McArthur, Sally L; Bondurant, Bruce; D'Ambruoso, Gemma D; Hall, Henry K; Brown, Michael F; Ross, Eric E; Saavedra, S Scott; Castner, David G

2008-05-06

Planar supported lipid bilayers that are stable under ambient atmospheric and ultra-high-vacuum conditions were prepared by cross-linking polymerization of bis-sorbylphosphatidylcholine (bis-SorbPC). X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed to investigate bilayers that were cross-linked using either redox-initiated radical polymerization or ultraviolet photopolymerization. The redox method yields a more structurally intact bilayer; however, the UV method is more compatible with incorporation of transmembrane proteins. UV polymerization was therefore used to prepare cross-linked bilayers with incorporated bovine rhodopsin, a light-activated, G-protein-coupled receptor (GPCR). A previous study (Subramaniam, V.; Alves, I. D.; Salgado, G. F. J.; Lau, P. W.; Wysocki, R. J.; Salamon, Z.; Tollin, G.; Hruby, V. J.; Brown, M. F.; Saavedra, S. S. J. Am. Chem. Soc. 2005, 127, 5320-5321) showed that rhodopsin retains photoactivity after incorporation into UV-polymerized bis-SorbPC, but did not address how the protein is associated with the bilayer. In this study, we show that rhodopsin is retained in supported bilayers of poly(bis-SorbPC) under ultra-high-vacuum conditions, on the basis of the increase in the XPS nitrogen concentration and the presence of characteristic amino acid peaks in the ToF-SIMS data. Angle-resolved XPS data show that the protein is inserted into the bilayer, rather than adsorbed on the bilayer surface. This is the first study to demonstrate the use of ultra-high-vacuum techniques for structural studies of supported proteolipid bilayers.

Residential Mobility, Self-Concept, and Positive Affect in Social Interactions

PubMed Central

Oishi, Shigehiro; Lun, Janetta; Sherman, Gary D.

2008-01-01

The present research examined (a) the link between personal history of residential mobility and the self-concept and (b) the implications of such a link for positive affect in social interactions. Study 1 showed that the personal self was more central to the self-definition of frequent movers than to that of nonmovers, whereas the collective self was more central to the self-definition of nonmovers than to that of frequent movers. Results from a laboratory and a 2-week event sampling study (Studies 2 and 3) demonstrated that frequent movers felt happier when an interaction partner accurately perceived their personal selves, whereas nonmovers felt happier when a partner accurately perceived their collective selves. These findings present the first direct evidence on how personal history of residential mobility is linked to important individual differences in the self and positive affect in social interactions. PMID:17605594

Residential mobility, self-concept, and positive affect in social interactions.

PubMed

Oishi, Shigehiro; Lun, Janetta; Sherman, Gary D

2007-07-01

The present research examined (a) the link between personal history of residential mobility and the self-concept and (b) the implications of such a link for positive affect in social interactions. Study 1 showed that the personal self was more central to the self-definition of frequent movers than to that of nonmovers, whereas the collective self was more central to the self-definition of nonmovers than to that of frequent movers. Results from a laboratory and a 2-week event sampling study (Studies 2 and 3) demonstrated that frequent movers felt happier when an interaction partner accurately perceived their personal selves, whereas nonmovers felt happier when a partner accurately perceived their collective selves. These findings present the first direct evidence on how personal history of residential mobility is linked to important individual differences in the self and positive affect in social interactions. Copyright 2007 APA, all rights reserved.

Scaling of global input-output networks

NASA Astrophysics Data System (ADS)

Liang, Sai; Qi, Zhengling; Qu, Shen; Zhu, Ji; Chiu, Anthony S. F.; Jia, Xiaoping; Xu, Ming

2016-06-01

Examining scaling patterns of networks can help understand how structural features relate to the behavior of the networks. Input-output networks consist of industries as nodes and inter-industrial exchanges of products as links. Previous studies consider limited measures for node strengths and link weights, and also ignore the impact of dataset choice. We consider a comprehensive set of indicators in this study that are important in economic analysis, and also examine the impact of dataset choice, by studying input-output networks in individual countries and the entire world. Results show that Burr, Log-Logistic, Log-normal, and Weibull distributions can better describe scaling patterns of global input-output networks. We also find that dataset choice has limited impacts on the observed scaling patterns. Our findings can help examine the quality of economic statistics, estimate missing data in economic statistics, and identify key nodes and links in input-output networks to support economic policymaking.

The properties of water in swollen cross-linked polystyrene sulfo acids

NASA Astrophysics Data System (ADS)

Gagarin, A. N.; Tokmachev, M. G.; Kovaleva, S. S.; Ferapontov, N. B.

2008-11-01

The properties of water in polystyrene sulfo acid gels with various cross-linking degrees were studied by optical volumetry and dynamic desorption porosimetry. The isotherms of water desorption obtained by dynamic desorption porosimetry coincided with isopiestic isotherms, which allowed this method to be recommended for the determination of the amount of water in polymer gels. Joint optical volumetry and dynamic desorption porosimetry studies showed that the interphase boundary in the cross-liked hydrophilic polymer-water system did not coincide with the visible gel boundary, because gels were two-phase systems, which contained water of two types, “free” and “bound.” The influence of the degree of polymer cross-linking on the amounts and properties of water of the two types was studied. It was shown that constants of water distribution in the polymer could be calculated from the dynamic desorption porosimetry data.

[eLearning-radiology.com--sustainability for quality assurance].

PubMed

Ketelsen, D; Talanow, R; Uder, M; Grunewald, M

2009-04-01

The aim of the study was to analyze the availability of published radiological e-learning tools and to establish a solution for quality assurance. Substantial pubmed research was performed to identify radiological e-learning tools. 181 e-learning programs were selected. As examples two databases expanding their programs with external links, Compare (n = 435 external links) and TNT-Radiology (n = 1078 external links), were evaluated. A concept for quality assurance was developed by an international taskforce. At the time of assessment, 56.4 % (102 / 181) of the investigated e-learning tools were accessible at their original URL. A subgroup analysis of programs published 5 to 8 years ago showed significantly inferior availability to programs published 3 to 5 years ago (p < 0.01). The analysis of external links showed 49.2 % and 61.0 % accessible links for the programs Compare (published 2003) and TNT-Radiology (published 2006), respectively. As a consequence, the domain www.eLearning-radiology.com was developed by the taskforce and published online. This tool allows authors to present their programs and users to evaluate the e-learning tools depending on several criteria in order to remove inoperable links and to obtain information about the complexity and quality of the e-learning tools. More than 50 % of investigated radiological e-learning tools on the Internet were not accessible after a period of 5 to 8 years. As a consequence, an independent, international tool for quality assurance was designed and published online under www.eLearning-radiology.com .

Modified properties of a glycated and cross-linked soy protein isolate by transglutaminase and an oligochitosan of 5 kDa.

PubMed

Fu, Miao; Zhao, Xin-Huai

2017-01-01

Soy protein is an important protein ingredient for the food industry; however, its properties can be improved by enzymatic and chemical modifications. This study applied a new enzymatic glycation and cross-linking to modify soy protein isolate (SPI), using an oligochitosan of 5 kDa and transglutaminase. Properties of the obtained glycated and cross-linked SPI (GC-SPI) were unknown and thus assessed. GC-SPI contained glucosamine of 13.6 g kg -1 protein, but less reactable &bond;NH 2 than SPI (0.42 vs. 0.50 mol kg -1 protein). Infrared spectra and circular dichroism results showed that GC-SPI other than SPI and cross-linked SPI had more &bond;OH in molecules, and was more disordered in secondary structure. In comparison with SPI, GC-SPI showed enhanced water-binding capacity, could form aggregates with enlarged hydrodynamic radius (180.2 vs. 82.9 nm) and negative zeta-potential (-31.2 vs. -27.7 mV) in dispersion, but exhibited lower thermal stability (e.g. greater mass loss) upon heating at a temperature above 288 °C. GC-SPI also had lower in vitro proteolytic digestibility than SPI due to the protein cross-linking. Oligochitosan of 5 kDa and transglutaminase can be used to glycate and cross-link SPI. This approach is applicable to generate potential protein ingredient with good hydration and dispersive stabilisation. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Bias in the Flesh

PubMed Central

Messing, Solomon; Jabon, Maria; Plaut, Ethan

2016-01-01

There is strong evidence linking skin complexion to negative stereotypes and adverse real-world outcomes. We extend these findings to political ad campaigns, in which skin complexion can be easily manipulated in ways that are difficult to detect. Devising a method to measure how dark a candidate appears in an image, this paper examines how complexion varied with ad content during the 2008 presidential election campaign (study 1). Findings show that darker images were more frequent in negative ads—especially those linking Obama to crime—which aired more frequently as Election Day approached. We then conduct an experiment to document how these darker images can activate stereotypes, and show that a subtle darkness manipulation is sufficient to activate the most negative stereotypes about Blacks—even when the candidate is a famous counter-stereotypical exemplar—Barack Obama (study 2). Further evidence of an evaluative penalty for darker skin comes from an observational study measuring affective responses to depictions of Obama with varying skin complexion, presented via the Affect Misattribution Procedure in the 2008 American National Election Study (study 3). This study demonstrates that darker images are used in a way that complements ad content, and shows that doing so can negatively affect how individuals evaluate candidates and think about politics. PMID:27257306

Literature Search through Mixed-Membership Community Discovery

NASA Astrophysics Data System (ADS)

Eliassi-Rad, Tina; Henderson, Keith

We introduce a new approach to literature search that is based on finding mixed-membership communities on an augmented co-authorship graph (ACA) with a scalable generative model. An ACA graph contains two types of edges: (1) coauthorship links and (2) links between researchers with substantial expertise overlap. Our solution eliminates the biases introduced by either looking at citations of a paper or doing a Web search. A case study on PubMed shows the benefits of our approach.

Climatic change by cloudiness linked to the spatial variability of sea surface temperatures

NASA Technical Reports Server (NTRS)

Otterman, J.

1975-01-01

An active role in modifying the earth's climate is suggested for low cloudiness over the circumarctic oceans. Such cloudiness, linked to the spatial differences in ocean surface temperatures, was studied. The temporal variations from year to year of ocean temperature patterns can be pronounced and therefore, the low cloudiness over this region should also show strong temporal variations, affecting the albedo of the earth and therefore the climate. Photographs are included.

Keratoconus corneal architecture after riboflavin/ultraviolet A cross-linking: Ultrastructural studies

PubMed Central

Almubrad, Turki; Paladini, Iacopo; Mencucci, Rita

2013-01-01

Purpose Study to investigate the effects of collagen cross-linking on the ultrastructural organization of the corneal stroma in the human keratoconus cornea (KC). Methods Three normal, three keratoconus (KC1, KC2, KC3), and three cross-linked keratoconus (CXL1, CXL2, CXL3) corneas were analyzed. The KC corneas were treated with a riboflavin-ultraviolet A (UVA) treatment (CXL) method described by Wollensak et al. Penetrating keratoplasty (PKP) was performed 6 months after treatment. All samples were processed for electron microscopy. Results The riboflavin-UVA-treated CXL corneal stroma showed interlacing lamellae in the anterior stroma followed by well-organized parallel running lamellae. The lamellae contained uniformly distributed collagen fibrils (CFs) decorated with normal proteoglycans (PGs). The CF diameter and interfibrillar spacing in the CXL cornea were significantly increased compared to those in the KC cornea. The PG area in the CXL corneas were significantly smaller than the PGs in the KC cornea. The epithelium and Bowman’s layer were also normal. On rare occasions, a thick basement membrane and collagenous pannus were also observed. Conclusions Corneal cross-linking leads to modifications of the cornea stroma. The KC corneal structure showed a modification in the CF diameter, interfibrillar spacing, and PG area. This resulted in a more uniform distribution of collagen fibrils, a key feature for corneal transparency. PMID:23878503

Discrimination-related health inequality and role of social capital among marriage migrant women in South Korea.

PubMed

Kim, Chang-O

2016-10-26

This study aimed to evaluate whether social capital could alleviate health inequality against racial discrimination and identify the critical nature of social capital that generates health inequality differences within the social context of South Korea. Using the data of the 2009 National Survey of Multicultural Families, a nationally representative sample in which 40,430 foreign wives participated, the concentration index (CI) was used to measure the discrimination-related inequalities in self-rated health and was decomposed into contributing factors. The results showed a significant concentration of poor self-rated health unfavorable to foreign wives who were highly discriminated (CI 0.023, standard error [SE] 0.001, p < .001). However, when the CIs were assessed among the subgroups of different social capital, no discrimination-related inequality in health was observed among the group of linking social capital (CI 0.008, SE 0.008, p .332). The total differential decomposition method showed two major factors that generate differences in health inequality between the groups of non-linking and linking social capital: protest against discrimination (35.8 %); experiences of discrimination (28.3 %). The present results indicated that linking social capital can be a useful resource of health resilience factor that equalizes discrimination-related health inequality among marriage migrant women in South Korea. This study provides additional evidence that social capital needs to be placed in its political context.

Links of the significant wave height distribution in the Mediterranean sea with the Northern Hemisphere teleconnection patterns

NASA Astrophysics Data System (ADS)

Lionello, P.; Galati, M. B.

2008-06-01

This study analyzes the link between the SWH (Significant Wave Height) distribution in the Mediterranean Sea during the second half of the 20th century and the Northern Hemisphere SLP (Sea Level Pressure) teleconnection patterns. The SWH distribution is computed using the WAM (WAve Model) forced by the surface wind fields provided by the ERA-40 reanalysis for the period 1958-2001. The time series of mid-latitude teleconnection patterns are downloaded from the NOAA web site. This study shows that several mid-latitude patterns are linked to the SWH field in the Mediterranean, especially in its western part during the cold season: East Atlantic Pattern (EA), Scandinavian Pattern (SCA), North Atlantic Oscillation (NAO), East Atlantic/West Russia Pattern (EA/WR) and East Pacific/ North Pacific Pattern (EP/NP). Though the East Atlantic pattern exerts the largest influence, it is not sufficient to characterize the dominant variability. NAO, though relevant, has an effect smaller than EA and comparable to other patterns. Some link results from possibly spurious structures. Patterns which have a very different global structure are associated to similar spatial features of the wave variability in the Mediterranean Sea. These two problems are, admittedly, shortcomings of this analysis, which shows the complexity of the response of the Mediterranean SWH to global scale SLP teleconnection patterns.

Drug-Triggered and Cross-Linked Self-Assembling Nanofibrous Hydrogels

PubMed Central

Kumar, Vivek A.; Shi, Siyu; Wang, Benjamin K.; Li, I-Che; Jalan, Abhishek A.; Sarkar, Biplab; Wickremasinghe, Navindee C.; Hartgerink, Jeffrey D.

2015-01-01

Self-assembly of multidomain peptides (MDP) can be tailored to carry payloads that modulate the extracellular environment. Controlled release of growth factors, cytokines, and small-molecule drugs allows for unique control of in vitro and in vivo responses. In this study, we demonstrate this process of ionic cross-linking of peptides using multivalent drugs to create hydrogels for sustained long-term delivery of drugs. Using phosphate, heparin, clodronate, trypan, and suramin, we demonstrate the utility of this strategy. Although all multivalent anions result in good hydrogel formation, demonstrating the generality of this approach, suramin led to the formation of the best hydrogels per unit concentration and was studied in greater detail. Suramin ionically cross-linked MDP into a fibrous meshwork as determined by scanning and transmission electron microscopy. We measured material storage and loss modulus using rheometry and showed a distinct increase in G′ and G″ as a function of suramin concentration. Release of suramin from scaffolds was determined using UV spectroscopy and showed prolonged release over a 30 day period. Suramin bioavailability and function were demonstrated by attenuated M1 polarization of THP-1 cells compared to positive control. Overall, this design strategy has allowed for the development of a novel class of polymeric delivery vehicles with generally long-term release and, in the case of suramin, cross-linked hydrogels that can modulate cellular phenotype. PMID:25831137

Effects of Link Annotations on Search Performance in Layered and Unlayered Hierarchically Organized Information Spaces.

ERIC Educational Resources Information Center

Fraser, Landon; Locatis, Craig

2001-01-01

Investigated the effects of link annotations on high school user search performance in Web hypertext environments having deep (layered) and shallow link structures. Results confirmed previous research that shallow link structures are better than deep (layered) link structures, and also showed that annotations had virtually no effect on search…

[Facial injections of hyaluronic acid-based fillers for malformations. Preliminary study regarding scar tissue improvement and cosmetic betterment].

PubMed

Franchi, G; Neiva-Vaz, C; Picard, A; Vazquez, M-P

2018-06-01

Cross-linked hyaluronic acid-based fillers have gained rapid acceptance for treating facial wrinkles, deep tissue folds and sunken areas due to aging. This study evaluates, in addition to space-filling properties, their effects on softness and elasticity as a secondary effect, following injection of 3 commercially available cross-linked hyaluronic acid-based fillers (15mg/mL, 17,5mg/mL and 20mg/mL) in patients presenting with congenital or acquired facial malformations. We started injecting gels of cross-linked hyaluronic acid-based fillers in those cases in 2013; we performed 46 sessions of injections in 32 patients, aged from 13-32. Clinical assessment was performed by the patient himself and by a plastic surgeon, 15 days after injections and 6-18 months later. Cross-linked hyaluronic acid-based fillers offered very subtle cosmetic results and supplemented surgery with a very high level of satisfaction of the patients. When injected in fibrosis, the first session enhanced softness and elasticity; the second session enhanced the volume. Cross-linked hyaluronic acid-based fillers fill sunken areas and better softness and elasticity of scar tissues. In addition to their well-understood space-filling function, as a secondary effect, the authors demonstrate that cross-linked hyaluronic acid-based fillers improve softness and elasticity of scarring tissues. Many experimental studies support our observations, showing that cross-linked hyaluronic acid stimulates the production of several extra-cellular matrix components, including dermal collagen and elastin. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Role of solvent-mediated carbodiimide cross-linking in fabrication of electrospun gelatin nanofibrous membranes as ophthalmic biomaterials.

PubMed

Chou, Shih-Feng; Luo, Li-Jyuan; Lai, Jui-Yang; Ma, David Hui-Kang

2017-02-01

Due to their ability to mimic the structure of extracellular matrix, electrospun gelatin nanofibers are promising cell scaffolding materials for tissue engineering applications. However, the hydrophilic gelatin molecules usually need stabilization before use in aqueous physiological environment. Considering that biomaterials cross-linked via film immersion technique may have a more homogeneous cross-linked structure than vapor phase cross-linking, this work aims to investigate the chemical modification of electrospun gelatin nanofibrous membranes by liquid phase carbodiimide in the presence of ethanol/water co-solvents with varying ethanol concentrations ranging from 80 to 99.5vol%. The results of characterization showed that increasing water content in the binary reaction solvent system increases the extent of cross-linking of gelatin nanofibers, but simultaneously promotes the effect of biopolymer swelling and distortion in fiber mat structure. As compared to non-cross-linked counterparts, carbodiimide treated gelatin nanofibrous mats exhibited better thermal and biological stability where the shrinkage temperature and resistance to enzymatic degradation varied in response to ethanol/water solvent composition-mediated generation of cross-links. Irrespective of their cross-linking density, all studied membrane samples did not induce any responses in ocular epithelial cell cultures derived from cornea, lens, and retina. Unlike many other cross-linking agents and/or methods (e.g., excessive vapor phase cross-linking) that may pose a risk of toxicity, our study demonstrated that these nanofibrous materials are well tolerated by anterior segment tissues. These findings also indicate the safety of using ethanol/water co-solvents for chemical cross-linking of gelatin to engineer nanofibrous materials with negligible biological effects. In summary, the present results suggest the importance of solvent-mediated carbodiimide cross-linking in modulating structure-property relationship without compromising in vitro and in vivo biocompatibility of electrospun gelatin nanofibers for future ophthalmic applications. Copyright © 2016 Elsevier B.V. All rights reserved.

A 4-channel coil array interconnection by analog direct modulation optical link for 1.5-T MRI.

PubMed

Yuan, Jing; Wei, Juan; Shen, Gary X

2008-10-01

Optical glass fiber shows great advantages over coaxial cables in terms of electromagnetic interference, thus, it should be considered a potential alternative for magnetic resonance imaging (MRI) receive coil interconnection, especially for a large number coil array at high field. In this paper, we propose a 4-channel analog direct modulation optical link for a 1.5-T MRI coil array interconnection. First, a general direct modulated optical link is compared to an external modulated optical link. And then the link performances of the proposed direct modulated optical link, including power gain, frequency response, and dynamic range, are analyzed and measured. Phantom and in vivo head images obtained using this optical link are demonstrated for comparison with those obtained by cable connections. The signal-to-noise (SNR) analysis shows that the optical link achieves 6%-8% SNR a improvement over coaxial cables by elimination of electrical interference between cables during MR signal transmission.

Structure analysis of a novel heteroxylan from the stem of Dendrobium officinale and anti-angiogenesis activities of its sulfated derivative.

PubMed

Yue, Han; Liu, Yanqiu; Qu, Huanhuan; Ding, Kan

2017-10-01

Dendrobium officinale Kimura et Migo (Tie-Pi-Shi-Hu), a precious folk medicine exhibiting multiple bioactivities, including antitumor, immune-enhancing and so on. Although evidences showed polysaccharide is one of the major bioactive substances from this herb, several of them were homogenous with fine structures elucidated. In this study, we showed a novel homogeneous heteroxylan obtained from alkali-extracted crude polysaccharide. It composed of arabinose, xylose, glucose and 4-O-methylglucuronic acid (4-MGA) as well as trace amount of rhamnose and galactose in a ratio of 8.9:62.7:8.5:12.3:3.9:3.7. We further showed that it contained a backbone of 1,4-linked β-d-xylan, with branches of 1,4-linked α-d-glucose, 1,3-linked α-l-rhamnose, and terminal-linked α-l-arabinose, β-d-galactose, 4-MGA, and β-d-xylose directly or indirectly attached to C-2 position of glycosyl residues on backbone. The sulfated derivative with substitution degree about 0.9 was prepared according to the chlorosulfonic acid (CSA)-pyridine method. Bioactivity tests suggested that the sulfated polysaccharide could significantly disrupt tube formation and inhibit the migration of human microvascular endothelial cells (HMEC-1) at a low concentration (0.29μM) in a dose-dependent way without significant cytotoxity. Copyright © 2017 Elsevier B.V. All rights reserved.

Heterogeneous Data Fusion Method to Estimate Travel Time Distributions in Congested Road Networks

PubMed Central

Lam, William H. K.; Li, Qingquan

2017-01-01

Travel times in congested urban road networks are highly stochastic. Provision of travel time distribution information, including both mean and variance, can be very useful for travelers to make reliable path choice decisions to ensure higher probability of on-time arrival. To this end, a heterogeneous data fusion method is proposed to estimate travel time distributions by fusing heterogeneous data from point and interval detectors. In the proposed method, link travel time distributions are first estimated from point detector observations. The travel time distributions of links without point detectors are imputed based on their spatial correlations with links that have point detectors. The estimated link travel time distributions are then fused with path travel time distributions obtained from the interval detectors using Dempster-Shafer evidence theory. Based on fused path travel time distribution, an optimization technique is further introduced to update link travel time distributions and their spatial correlations. A case study was performed using real-world data from Hong Kong and showed that the proposed method obtained accurate and robust estimations of link and path travel time distributions in congested road networks. PMID:29210978

Heterogeneous Data Fusion Method to Estimate Travel Time Distributions in Congested Road Networks.

PubMed

Shi, Chaoyang; Chen, Bi Yu; Lam, William H K; Li, Qingquan

2017-12-06

Travel times in congested urban road networks are highly stochastic. Provision of travel time distribution information, including both mean and variance, can be very useful for travelers to make reliable path choice decisions to ensure higher probability of on-time arrival. To this end, a heterogeneous data fusion method is proposed to estimate travel time distributions by fusing heterogeneous data from point and interval detectors. In the proposed method, link travel time distributions are first estimated from point detector observations. The travel time distributions of links without point detectors are imputed based on their spatial correlations with links that have point detectors. The estimated link travel time distributions are then fused with path travel time distributions obtained from the interval detectors using Dempster-Shafer evidence theory. Based on fused path travel time distribution, an optimization technique is further introduced to update link travel time distributions and their spatial correlations. A case study was performed using real-world data from Hong Kong and showed that the proposed method obtained accurate and robust estimations of link and path travel time distributions in congested road networks.

Human monoclonal macroglobulins with specificity for Klebsiella K polysaccharides that contain 3,4-pyruvylated-D-galactose and 4,6- pyruvylated-D-galactose

PubMed Central

1980-01-01

Two human IgM myeloma proteins, IgMWEA and IgMMAY, were found to react with agar and Klebsiella polysaccharides that contain pyruvylated D- galactose (DGal). Quantitative precipitin data and precipitin inhibition studies with methyl alpha- and beta-glycosides of 4,6- pyruvylated-D-galactose showed their combining sites to be different, although each was directed against the pyruvylated-D-Gal, one reacting most specifically with Klebsiella polysaccharides with terminal nonreducing beta-linked 2,4 pyruvylated-D-Gal, whereas the other reacted equally well with Klebsiella polysaccharides that contain 3,4 beta-linked and 4,6 alpha-linked terminal nonreducing pyruvylated-DGal. Inhibition studies showed that both sites are directed toward one of the two space isomers of 3,4- or 4,6-pyruvylated DGal, the form in which the methyl group of the pyruvate is equatorial, or endo, and its carboxyl group axial, or exo, to the plane of the acetal ring. Coprecipitation studies showed the combining site of IgMWEA to be located on an (Fab')2 fragment and not on the (Fc)5mu fragment. The monoclonal peak in the serum of IgMMAY was specifically precipitated by Klebsiella polysaccharide. Myeloma proteins with specificities of this type may occur with reasonable frequency in humans and may be a consequence of clonal expansion from inapparent infection, carrier states, or disease produced by various Klebsiella organisms. PMID:6158553

Improvement of Janus Using Pegasus 1-Meter Resolution Database With a Transputer Network

DTIC Science & Technology

1994-03-01

Figure 4.9 shows the six jacks on the end of the HSI-card. Facing the back of the SPARC Station LINKO LINKI LINK2 LINK3 DOWN UP Figure 4.9: HSI-Card Link...shown in Figure 4.22. Facing the back of the Sun SPARC Station LINK0 LINKI LINK2 LINK3 DOWN UP "b Telephone Cable Facing the front of the Remote Tram...Holder LINKO LINKI LINK2 LINK3 DOWN UPI Figure 4.20: The Connection Between Sun SPARC Station and Remote Tram Holder 58 (3) Se.inu Up t• Link Speed

I can read it in your eyes: what eye movements tell us about visuo-attentional processes in developmental dyslexia.

PubMed

Bellocchi, Stéphanie; Muneaux, Mathilde; Bastien-Toniazzo, Mireille; Ducrot, Stéphanie

2013-01-01

Most studies today agree about the link between visual-attention and oculomotor control during reading: attention seems to affect saccadic programming, that is, the position where the eyes land in a word. Moreover, recent studies show that visuo-attentional processes are strictly linked to normal and impaired reading. In particular, a large body of research has found evidence of defective visuo-attentional processes in dyslexics. What do eye movements tell us about visuo-attentional deficits in developmental dyslexia? The purpose of this paper is to explore the link between oculomotor control and dyslexia, taking into account its heterogeneous manifestation and comorbidity. Clinical perspectives in the use of the eye-movements approach to better explore and understand reading impairments are discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Chiral Differentiation of DNA Adducts Formed by Enantiomeric Analogues of Antitumor Cisplatin Is Sequence-Dependent

PubMed Central

Delalande, Olivier; Malina, Jaroslav; Brabec, Viktor; Kozelka, Jiří

2005-01-01

1,2-GG intrastrand cross-links formed in DNA by the enantiomeric complexes [PtCl2(R,R-2,3-diaminobutane (DAB))] and [PtCl2(S,S-DAB)] were studied by biophysical methods. Molecular modeling revealed that structure of the cross-links formed at the TGGT sequence was affected by repulsion between the 5′-directed methyl group of the DAB ligand and the methyl group of the 5′-thymine of the TGGT fragment. Molecular dynamics simulations of the solvated platinated duplexes and our recent structural data indicated that the adduct of [PtCl2(R,R-DAB)] alleviated this repulsion by unwinding the TpG step, whereas the adduct of [PtCl2(S,S-DAB)] avoided the unfavorable methyl-methyl interaction by decreasing the kink angle. Electrophoretic retardation measurements on DNA duplexes containing 1,2-GG intrastrand cross-links of Pt(R,R-DAB)2+ or Pt(S,S-DAB)2+ at a CGGA site showed that in this sequence both enantiomers distorted the double helix to the identical extent similar to that found previously for the same sequence containing the cross-links of the parent antitumor \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}cis-{\\mathrm{Pt}}({\\mathrm{NH}}_{3})_{2}^{2+}\\end{equation*}\\end{document} (cisplatin). In addition, the adducts showed similar affinities toward the high-mobility-group box 1 proteins. Hence, whereas the structural perturbation induced in DNA by 1,2-GG intrastrand cross-links of cisplatin does not depend largely on the bases flanking the cross-links, the perturbation related to GG cross-linking by bulkier platinum diamine derivatives does. PMID:15805172

Temporal development of near-native functional properties and correlations with qMRI in self-assembling fibrocartilage treated with exogenous lysyl oxidase homolog 2.

PubMed

Hadidi, Pasha; Cissell, Derek D; Hu, Jerry C; Athanasiou, Kyriacos A

2017-12-01

Advances in cartilage tissue engineering have led to constructs with mechanical integrity and biochemical composition increasingly resembling that of native tissues. In particular, collagen cross-linking with lysyl oxidase has been used to significantly enhance the mechanical properties of engineered neotissues. In this study, development of collagen cross-links over time, and correlations with tensile properties, were examined in self-assembling neotissues. Additionally, quantitative MRI metrics were examined in relation to construct mechanical properties as well as pyridinoline cross-link content and other engineered tissue components. Scaffold-free meniscus fibrocartilage was cultured in the presence of exogenous lysyl oxidase, and assessed at multiple time points over 8weeks starting from the first week of culture. Engineered constructs demonstrated a 9.9-fold increase in pyridinoline content, reaching 77% of native tissue values, after 8weeks of culture. Additionally, engineered tissues reached 66% of the Young's modulus in the radial direction of native tissues. Further, collagen cross-links were found to correlate with tensile properties, contributing 67% of the tensile strength of engineered neocartilages. Finally, examination of quantitative MRI metrics revealed several correlations with mechanical and biochemical properties of engineered constructs. This study displays the importance of culture duration for collagen cross-link formation, and demonstrates the potential of quantitative MRI in investigating properties of engineered cartilages. This is the first study to demonstrate near-native cross-link content in an engineered tissue, and the first study to quantify pyridinoline cross-link development over time in a self-assembling tissue. Additionally, this work shows the relative contributions of collagen and pyridinoline to the tensile properties of collagenous tissue for the first time. Furthermore, this is the first investigation to identify a relationship between qMRI metrics and the pyridinoline cross-link content of an engineered collagenous tissue. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The differential effects of gratitude and sleep on psychological distress in patients with chronic pain.

PubMed

Ng, Mei-Yee; Wong, Wing-Sze

2013-02-01

This study aimed to examine the possible cross-sectional mediating role of sleep in the relationship of gratitude with depression and anxiety in patients with chronic pain. A total of 224 patients with chronic pain completed structured questionnaires assessing chronic pain, depression and anxiety symptoms, gratitude, and sleep disturbances. Results of multiple regression analyses yielded a modest mediating effect for sleep on the gratitude-depression link whereas a stronger mediating effect was found for sleep on the gratitude-anxiety link. These data show much of the effect of gratitude on depression was direct whereas sleep exerted a stronger mediating effect on the gratitude-anxiety link.

Linking biomedical engineering ethics case study approach and policy.

PubMed

Dibrell, William; Dobie, Elizabeth Ann

2007-01-01

In this paper we link bioengineering case study methods to the development of policy. The case study approach to ethics is an excellent way to show the complex nature of practical/moral reasoning. This approach can, however, lead to a kind of overwhelming complexity. The individual nature of each case makes it difficult to identify the most important information and difficult to see what moral considerations are most relevant. In order to make the overwhelming complexity less debilitating, we present a framework for moral decision making derived from suggestions made by W.D. Ross and Virginia Held. Ross articulates the multiple sources of morality and Held deepens the discussion by reminding us of the foundational importance of care and sympathy to our moral natures. We show how to use the notion of prima facie duty and discuss moral conflict. In doing this, we show how the framework, applied to cases, can be of assistance in helping us develop policies and codes of ethics with sufficient plasticity to be useful in the complex world of the bioengineer.

Effect of link oriented self-healing on resilience of networks

NASA Astrophysics Data System (ADS)

Shang, Yilun

2016-08-01

Many real, complex systems, such as the human brain and skin with their biological networks or intelligent material systems consisting of composite functional liquids, exhibit a noticeable capability of self-healing. Here, we study a network model with arbitrary degree distributions possessing natural link oriented recovery mechanisms, whereby a failed link can be recovered if its two end nodes maintain a sufficient proportion of functional links. These mechanisms are pertinent for many spontaneous healing and manual repair phenomena, interpolating smoothly between complete healing and no healing scenarios. We show that the self-healing strategies have profound impact on resilience of homogeneous and heterogeneous networks employing a percolation threshold, fraction of giant cluster, and link robustness index. The self-healing effect induces distinct resilience characteristics for scale-free networks under random failures and intentional attacks, and a resilience crossover has been observed at certain level of self-healing. Our work highlights the significance of understanding the competition between healing and collapsing in the resilience of complex networks.

Social Relatedness and Physical Health Are More Strongly Related in Older Than Younger Adults: Findings from the Korean Adult Longitudinal Study

PubMed Central

Choi, Eunsoo; Kwon, Yuri; Lee, Minha; Choi, Jongan; Choi, Incheol

2018-01-01

Previous research indicates that social relatedness is beneficial to physical health; however, findings on the relative strength of the relationship between these variables have been inconsistent. The present study employed cross-sectional survey (Study 1) and a daily diary survey (Study 2) to examine the link between social relatedness and physical health by age. Using a representative sample of Korean adults (N = 371) aged from 20 to 69, Study 1 examines the link between social relatedness (loneliness, perceived social support) and physical health (physical symptoms, chronic health conditions) using age as a moderator. The results show that participants' age moderates the association between social relatedness and physical health. Study 2 (N = 384) further corroborated the findings from Study 1 by showing that when controlling for the physical symptoms experienced prior to the daily diary reports, the level of loneliness experienced over a 13-day period exacerbates the age differences in the physical symptoms. The present study thus provides converging evidence that social relatedness plays a significant role in physical health, particularly in the older population. PMID:29403415

In vivo study on alkylation site in DNA by the bifunctional dianhydrogalactitol.

PubMed

Institoris, E

1981-05-01

In vivo alkylation of Yoshida sarcoma cell DNA by 3H-labelled 1,2:5,6-dianhydrogalactitol (DAG) yielded N-7 monogalactitylguanines and 1,6-di-(guanin-7-yl)-galactitol, similar to the alkylated products obtained by in vitro reaction of DNA with dianhydrogalactitol in neutral solution. The ratio between monoalkylguanines and diguaninyl product was 2-2.5, slightly increasing with doses. Persistence of alkylated products in DNA was followed in function of time. There was no significant loss of either monoalkylated bases or diguaninyl derivative during the observation period i.e. 7-24 h after treatment. In contrast, the physical measurements of the amount of renaturable DNA showed a rapid opening of cross-links in the same period. Taking the presence of diguaninyl moiety as an indicator of cross-links in DNA, these two latter findings show an apparent contradiction which could be reconciled however by the mechanism proposed by Reid and Walker (Biochim. Biophys. Acta, 179 (1969) 179) for the removal of cross-linkage induced by HN2. Accordingly, one arm of the cross-links is removed, probably enzymically, leaving the DNA non-renaturable, while the other arm of cross-link is still covalently attached to the DNA molecule rendering possible the detection of diguaninyl moiety in DNA at some later time. This concept for the removal of cross-links from DNA seems to be supported by our results too.

A clade of Listeria monocytogenes serotype 4b variant strains linked to recent listeriosis outbreaks associated with produce from a defined geographic region in the US.

PubMed

Burall, Laurel S; Grim, Christopher J; Datta, Atin R

2017-01-01

Four listeriosis incidences/outbreaks, spanning 19 months, have been linked to Listeria monocytogenes serotype 4b variant (4bV) strains. Three of these incidents can be linked to a defined geographical region, while the fourth is likely to be linked. In this study, whole genome sequencing (WGS) of strains from these incidents was used for genomic comparisons using two approached. The first was JSpecies tetramer, which analyzed tetranucleotide frequency to assess relatedness. The second, the CFSAN SNP Pipeline, was used to perform WGS SNP analyses against three different reference genomes to evaluate relatedness by SNP distances. In each case, unrelated strains were included as controls. The analyses showed that strains from these incidents form a highly related clade with SNP differences of ≤101 within the clade and >9000 against other strains. Multi-Virulence-Locus Sequence Typing, a third standardized approach for evaluation relatedness, was used to assess the genetic drift in six conserved, known virulence loci and showed a different clustering pattern indicating possible differences in selection pressure experienced by these genes. These data suggest a high degree of relatedness among these 4bV strains linked to a defined geographic region and also highlight the possibility of alterations related to adaptation and virulence.

Structural characterization and inhibition on α-d-glucosidase activity of non-starch polysaccharides from Fagopyrum tartaricum.

PubMed

Wang, Xiao-Ting; Zhu, Zhen-Yuan; Zhao, Liang; Sun, Hui-Qing; Meng, Meng; Zhang, Jin-Yu; Zhang, Yong-Min

2016-11-20

In the present study, the crude polysaccharide was extracted from Fagopyrum tartaricum and purified by Sephadex G-25 and G-75 column to produce a polysaccharide fraction termed TBP-II. Its average molecular weight was 26kDa. The structural characterization of TBP-II was investigated by gas chromatography, periodate oxidation-Smith degradation, Methylation and NMR. Congo red was applied to explore its advanced structures. The results revealed that chemical composition and structural characteristic of TBP-II was mainly consisted of galactose, arabinose, xylose and glucose with a molar ratio of 0.7:1:6.3:74.2. The backbone of TBP-II was composed of (1→4)-linked α-d-glucopyranosyl (Glcp), while the branches comprised of (1→3)-linked α-d-glucopyranosyl (Glcp), (1→6)-linked α-d-galactopyranosyl (Galp) and (1→2,4)-linked α-d-rhamnopyranosyl (Rhap). The structure of TBP-II was 1,3 and 1,6-branched-galactorhamnoglucan that had a linear backbone of (1→4)-linked α-d-glucopyranose (Glcp). Using Congo red assay showed that it was absent of triple helix structure. The α-d-glucosidase inhibitory activity of TBP-II was determined using acarbose as positive control. The result showed that the inhibition rate depended on the concentration of polysaccharides. Copyright © 2016 Elsevier Ltd. All rights reserved.

Parasites Affect Food Web Structure Primarily through Increased Diversity and Complexity

PubMed Central

Dunne, Jennifer A.; Lafferty, Kevin D.; Dobson, Andrew P.; Hechinger, Ryan F.; Kuris, Armand M.; Martinez, Neo D.; McLaughlin, John P.; Mouritsen, Kim N.; Poulin, Robert; Reise, Karsten; Stouffer, Daniel B.; Thieltges, David W.; Williams, Richard J.; Zander, Claus Dieter

2013-01-01

Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of parasites or from changes to diversity and complexity. We analyzed seven highly resolved food webs that include metazoan parasite data. Our analyses show that adding parasites usually increases link density and connectance (simple measures of complexity), particularly when including concomitant links (links from predators to parasites of their prey). However, we clarify prior claims that parasites “dominate” food web links. Although parasites can be involved in a majority of links, in most cases classic predation links outnumber classic parasitism links. Regarding network structure, observed changes in degree distributions, 14 commonly studied metrics, and link probabilities are consistent with scale-dependent changes in structure associated with changes in diversity and complexity. Parasite and free-living species thus have similar effects on these aspects of structure. However, two changes point to unique roles of parasites. First, adding parasites and concomitant links strongly alters the frequency of most motifs of interactions among three taxa, reflecting parasites' roles as resources for predators of their hosts, driven by trophic intimacy with their hosts. Second, compared to free-living consumers, many parasites' feeding niches appear broader and less contiguous, which may reflect complex life cycles and small body sizes. This study provides new insights about generic versus unique impacts of parasites on food web structure, extends the generality of food web theory, gives a more rigorous framework for assessing the impact of any species on trophic organization, identifies limitations of current food web models, and provides direction for future structural and dynamical models. PMID:23776404

Parasites affect food web structure primarily through increased diversity and complexity

USGS Publications Warehouse

Dunne, Jennifer A.; Lafferty, Kevin D.; Dobson, Andrew P.; Hechinger, Ryan F.; Kuris, Armand M.; Martinez, Neo D.; McLaughlin, John P.; Mouritsen, Kim N.; Poulin, Robert; Reise, Karsten; Stouffer, Daniel B.; Thieltges, David W.; Williams, Richard J.; Zander, Claus Dieter

2013-01-01

Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of parasites or from changes to diversity and complexity. We analyzed seven highly resolved food webs that include metazoan parasite data. Our analyses show that adding parasites usually increases link density and connectance (simple measures of complexity), particularly when including concomitant links (links from predators to parasites of their prey). However, we clarify prior claims that parasites ‘‘dominate’’ food web links. Although parasites can be involved in a majority of links, in most cases classic predation links outnumber classic parasitism links. Regarding network structure, observed changes in degree distributions, 14 commonly studied metrics, and link probabilities are consistent with scale-dependent changes in structure associated with changes in diversity and complexity. Parasite and free-living species thus have similar effects on these aspects of structure. However, two changes point to unique roles of parasites. First, adding parasites and concomitant links strongly alters the frequency of most motifs of interactions among three taxa, reflecting parasites’ roles as resources for predators of their hosts, driven by trophic intimacy with their hosts. Second, compared to free-living consumers, many parasites’ feeding niches appear broader and less contiguous, which may reflect complex life cycles and small body sizes. This study provides new insights about generic versus unique impacts of parasites on food web structure, extends the generality of food web theory, gives a more rigorous framework for assessing the impact of any species on trophic organization, identifies limitations of current food web models, and provides direction for future structural and dynamical models.

Parasites affect food web structure primarily through increased diversity and complexity.

PubMed

Dunne, Jennifer A; Lafferty, Kevin D; Dobson, Andrew P; Hechinger, Ryan F; Kuris, Armand M; Martinez, Neo D; McLaughlin, John P; Mouritsen, Kim N; Poulin, Robert; Reise, Karsten; Stouffer, Daniel B; Thieltges, David W; Williams, Richard J; Zander, Claus Dieter

2013-01-01

Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of parasites or from changes to diversity and complexity. We analyzed seven highly resolved food webs that include metazoan parasite data. Our analyses show that adding parasites usually increases link density and connectance (simple measures of complexity), particularly when including concomitant links (links from predators to parasites of their prey). However, we clarify prior claims that parasites "dominate" food web links. Although parasites can be involved in a majority of links, in most cases classic predation links outnumber classic parasitism links. Regarding network structure, observed changes in degree distributions, 14 commonly studied metrics, and link probabilities are consistent with scale-dependent changes in structure associated with changes in diversity and complexity. Parasite and free-living species thus have similar effects on these aspects of structure. However, two changes point to unique roles of parasites. First, adding parasites and concomitant links strongly alters the frequency of most motifs of interactions among three taxa, reflecting parasites' roles as resources for predators of their hosts, driven by trophic intimacy with their hosts. Second, compared to free-living consumers, many parasites' feeding niches appear broader and less contiguous, which may reflect complex life cycles and small body sizes. This study provides new insights about generic versus unique impacts of parasites on food web structure, extends the generality of food web theory, gives a more rigorous framework for assessing the impact of any species on trophic organization, identifies limitations of current food web models, and provides direction for future structural and dynamical models.

Study the adsorption of sulfates by high cross-linked polystyrene divinylbenzene anion-exchange resin

NASA Astrophysics Data System (ADS)

Fathy, Mahmoud; Moghny, Th. Abdel; Awadallah, Ahmed E.; El-Bellihi, Abdel-Hameed A.-A.

2017-03-01

In response to rising concerns about the effect of sulfate on water quality, human health, and agriculture, many jurisdictions around the world are imposing tighter regulations for sulfate discharge. This is driving the need for environmental compliance in industries like mining, metal processing, pulp and paper, sewage treatment, and chemical manufacturing. The sulfate removal from synthetic water by high cross-linked polystyrene divinylbenzene resin was studied at batch experiments in this study. The effect of pH, contact time, sulfates concentration, and adsorbent dose on the sulfate sequestration was investigated. The optimum conditions were studied on Saline water as a case study. The results showed that with increasing of the absorbent amount; contact time, and pH improve the efficiency of sulfate removal. The maximum sulfates uptake was obtained in pH and contact time 3.0 and 120 min, respectively. Also, with increasing initial concentration of sulfates in water, the efficiency of sulfate removal decreased. The obtained results in this study were matched with Freundlich isotherm and pseudo-second-order kinetic. The maximum adsorption capacity (Qm) and constant rate were found 0.318 (mg/g) and 0.21 (mg/g.min), respectively. This study also showed that in the optimum conditions, the sulfate removal efficiency from Saline water by 0.1 mg/L sulfates was 65.64 %. Eventually, high cross-linked polystyrene divinylbenzene resin is recommended as a suitable and low cost absorbent to sulfate removal from aqueous solutions.

Hydrographs showing groundwater levels for selected wells in the Puyallup River watershed and vicinity, Pierce and King Counties, Washington

USGS Publications Warehouse

Lane, R.C.; Julich, R.J.; Justin, G.B.

2013-01-01

Hydrographs of groundwater levels for selected wells in and adjacent to the Puyallup River watershed in Pierce and King Counties, Washington, are presented using an interactive Web-based map of the study area to illustrate changes in groundwater levels on a monthly and seasonal basis. The interactive map displays well locations that link to the hydrographs, which in turn link to the U.S. Geological Survey National Water Information System, Groundwater Site Inventory System.

Sorption of adamantane phenylamide derivatives on hyper-cross-linked polystyrene from water-acetonitrile eluents

NASA Astrophysics Data System (ADS)

Shafigulin, R. V.; Konstantinov, A. V.; Bulanova, A. V.; Il'in, M. M.; Davankov, V. A.

2016-11-01

Study of the main physicochemical features of the sorption of phenylamide adamantane derivatives on hyper-cross-linked polystyrene from water-acetonitrile solutions shows that both hydrophobic and electronic interactions make a large contribution to retention, especially for a chlorine-containing derivative in which there are π- p and π- d interactions between the outer-shell electrons of the chlorine atom in addition to π- π interactions between aromatic fragments of the sorbate and sorbent.

Sex chromosome linked genetic variance and the evolution of sexual dimorphism of quantitative traits.

PubMed

Husby, Arild; Schielzeth, Holger; Forstmeier, Wolfgang; Gustafsson, Lars; Qvarnström, Anna

2013-03-01

Theory predicts that sex chromsome linkage should reduce intersexual genetic correlations thereby allowing the evolution of sexual dimorphism. Empirical evidence for sex linkage has come largely from crosses and few studies have examined how sexual dimorphism and sex linkage are related within outbred populations. Here, we use data on an array of different traits measured on over 10,000 individuals from two pedigreed populations of birds (collared flycatcher and zebra finch) to estimate the amount of sex-linked genetic variance (h(2)z ). Of 17 traits examined, eight showed a nonzero h(2)Z estimate but only four were significantly different from zero (wing patch size and tarsus length in collared flycatchers, wing length and beak color in zebra finches). We further tested how sexual dimorphism and the mode of selection operating on the trait relate to the proportion of sex-linked genetic variance. Sexually selected traits did not show higher h(2)Z than morphological traits and there was only a weak positive relationship between h(2)Z and sexual dimorphism. However, given the relative scarcity of empirical studies, it is premature to make conclusions about the role of sex chromosome linkage in the evolution of sexual dimorphism. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Parental bonding and depression: personality as a mediating factor.

PubMed

Avagianou, Penelope-Alexia; Zafiropoulou, Maria

2008-01-01

According to Bowlby's theory of attachment, the role of early experience and parenting is of crucial importance to child development and mental health. In addition, several research findings suggest that parental bonding and different types of attachment play a crucial role in personality development. The present study examines the association between parental bonding experiences (lack of parental care, overprotection or both) and depression during adulthood. The objective of the present study was to evaluate different personality dimensions as possible mediators of the relation between perceptions of parental bonding and depressive symptoms in adult life. 181 participants (15- 49-years-old) completed the Parental Bonding Instrument (PBI), the Beck Depression Inventory (BDI) and the 16 Personality Factor Questionnaire (16PF). The results show that lack of parental care and overprotection is linked with depressive symptoms and a number of personality characteristics, such as low self-esteem, introversion, distress and emotional instability. In contrast, high care and low protection (optimal bonding) is linked with increased self-confidence, less distress and less depressive symptoms. The results presented here are in line with Bowlby's theory of attachment and show that parental bonding is linked with problematic personality development and psychopathology. The present study provided evidence that personality factors may mediate the observed relationship between parental rearing style and depression. The potential causal mechanisms warrant longitudinal evaluation.

A socio-historical approach to policy analysis: the case of the Brazilian Workers' Food Policy.

PubMed

Costa-Souza, Jamacy; Vieira-da-Silva, Ligia Maria; Pinell, Patrice

2018-02-05

Policy analyses based on traditional or structuralist definitions of the state are important, but they have some limitations for explaining processes related to policymaking, implementation, and results. Bourdieusian sociology links the analysis to objective and subjective dimensions of social practices and can help elucidate these phenomena. This article provides such empirical evidence by analyzing the social genesis of a Brazilian policy that currently serves 18 million workers and was established by the state in 1976 through the Fiscal Incentives Program for Workers' Nutrition (PIFAT/PAT). The study linked the analysis of the trajectory of social agents involved in the policy's formulation to the historical conditions that allowed the policy to exist in the first place. Although the literature treats the policy as a workers' food program (PAT), the current study showed that it actually represented a new model for paying financial subsidies to companies that provided food to their employees, meanwhile upgrading the commercial market for collective meals. The study further showed that the program emerged as an administrative policy, but linked to economic agents. The program became a specific social space in which issues related to workers' nutrition became secondary, but useful for disguising what had been an explicit side of its genesis, namely its essentially fiscal nature.

Enhancement of the NMSU Channel Error Simulator to Provide User-Selectable Link Delays

NASA Technical Reports Server (NTRS)

Horan, Stephen; Wang, Ru-Hai

2000-01-01

This is the third in a continuing series of reports describing the development of the Space-to-Ground Link Simulator (SGLS) to be used for testing data transfers under simulated space channel conditions. The SGLS is based upon Virtual Instrument (VI) software techniques for managing the error generation, link data rate configuration, and, now, selection of the link delay value. In this report we detail the changes that needed to be made to the SGLS VI configuration to permit link delays to be added to the basic error generation and link data rate control capabilities. This was accomplished by modifying the rate-splitting VIs to include a buffer the hold the incoming data for the duration selected by the user to emulate the channel link delay. In sample tests of this configuration, the TCP/IP(sub ftp) service and the SCPS(sub fp) service were used to transmit 10-KB data files using both symmetric (both forward and return links set to 115200 bps) and unsymmetric (forward link set at 2400 bps and a return link set at 115200 bps) link configurations. Transmission times were recorded at bit error rates of 0 through 10(exp -5) to give an indication of the link performance. In these tests. we noted separate timings for the protocol setup time to initiate the file transfer and the variation in the actual file transfer time caused by channel errors. Both protocols showed similar performance to that seen earlier for the symmetric and unsymmetric channels. This time, the delays in establishing the file protocol also showed that these delays could double the transmission time and need to be accounted for in mission planning. Both protocols also showed a difficulty in transmitting large data files over large link delays. In these tests, there was no clear favorite between the TCP/IP(sub ftp) and the SCPS(sub fp). Based upon these tests, further testing is recommended to extend the results to different file transfer configurations.

Decoupling Identification for Serial Two-Link Two-Inertia System

NASA Astrophysics Data System (ADS)

Oaki, Junji; Adachi, Shuichi

The purpose of our study is to develop a precise model by applying the technique of system identification for the model-based control of a nonlinear robot arm, under taking joint-elasticity into consideration. We previously proposed a systematic identification method, called “decoupling identification,” for a “SCARA-type” planar two-link robot arm with elastic joints caused by the Harmonic-drive® reduction gears. The proposed method serves as an extension of the conventional rigid-joint-model-based identification. The robot arm is treated as a serial two-link two-inertia system with nonlinearity. The decoupling identification method using link-accelerometer signals enables the serial two-link two-inertia system to be divided into two linear one-link two-inertia systems. The MATLAB®'s commands for state-space model estimation are utilized in the proposed method. Physical parameters such as motor inertias, link inertias, joint-friction coefficients, and joint-spring coefficients are estimated through the identified one-link two-inertia systems using a gray-box approach. This paper describes accuracy evaluations using the two-link arm for the decoupling identification method under introducing closed-loop-controlled elements and varying amplitude-setup of identification-input. Experimental results show that the identification method also works with closed-loop-controlled elements. Therefore, the identification method is applicable to a “PUMA-type” vertical robot arm under gravity.

Uncovering curvilinear relationships between conscientiousness and job performance: how theoretically appropriate measurement makes an empirical difference.

PubMed

Carter, Nathan T; Dalal, Dev K; Boyce, Anthony S; O'Connell, Matthew S; Kung, Mei-Chuan; Delgado, Kristin M

2014-07-01

The personality trait of conscientiousness has seen considerable attention from applied psychologists due to its efficacy for predicting job performance across performance dimensions and occupations. However, recent theoretical and empirical developments have questioned the assumption that more conscientiousness always results in better job performance, suggesting a curvilinear link between the 2. Despite these developments, the results of studies directly testing the idea have been mixed. Here, we propose this link has been obscured by another pervasive assumption known as the dominance model of measurement: that higher scores on traditional personality measures always indicate higher levels of conscientiousness. Recent research suggests dominance models show inferior fit to personality test scores as compared to ideal point models that allow for curvilinear relationships between traits and scores. Using data from 2 different samples of job incumbents, we show the rank-order changes that result from using an ideal point model expose a curvilinear link between conscientiousness and job performance 100% of the time, whereas results using dominance models show mixed results, similar to the current state of the literature. Finally, with an independent cross-validation sample, we show that selection based on predicted performance using ideal point scores results in more favorable objective hiring outcomes. Implications for practice and future research are discussed.

Oligo(ethylene glycol)-sidechain microgels prepared in absence of cross-linking agent: Polymerization, characterization and variation of particle deformability.

PubMed

Welsch, Nicole; Lyon, L Andrew

2017-01-01

We present a systematic study of self-cross-linked microgels formed by precipitation polymerization of oligo ethylene glycol methacrylates. The cross-linking density of these microgels and, thus, the network flexibility can be easily tuned through the modulation of the reaction temperature during polymerization. Microgels prepared in absence of any difunctional monomer, i.e. cross-linker, show enhanced deformability and particle spreading on solid surfaces as compared to microgels cross-linked with varying amounts of poly(ethylene glycol diacrylate) (PEG-DA) in addition to self-crosslinking. Particles prepared at low reaction temperatures exhibit the highest degree of spreading due to the lightly cross-linked and flexible polymer network. Moreover, AFM force spectroscopy studies suggest that cross-linker-free microgels constitute of a more homogeneous polymer network than PEG-DA cross-linked particles and have elastic moduli at the particle apex that are ~5 times smaller than the moduli of 5 mol-% PEG-DA cross-linked microgels. Resistive pulse sensing experiments demonstrate that microgels prepared at 75 and 80°C without PEG-DA are able to deform significantly to pass through nanopores that are smaller than the microgel size. Additionally, we found that polymer network flexibility of microgels is a useful tool to control the formation of particle dewetting patterns. This offers a promising new avenue for build-up of 2D self-assembled particle structures with patterned chemical and mechanical properties.

Oligo(ethylene glycol)-sidechain microgels prepared in absence of cross-linking agent: Polymerization, characterization and variation of particle deformability

PubMed Central

Lyon, L. Andrew

2017-01-01

We present a systematic study of self-cross-linked microgels formed by precipitation polymerization of oligo ethylene glycol methacrylates. The cross-linking density of these microgels and, thus, the network flexibility can be easily tuned through the modulation of the reaction temperature during polymerization. Microgels prepared in absence of any difunctional monomer, i.e. cross-linker, show enhanced deformability and particle spreading on solid surfaces as compared to microgels cross-linked with varying amounts of poly(ethylene glycol diacrylate) (PEG-DA) in addition to self-crosslinking. Particles prepared at low reaction temperatures exhibit the highest degree of spreading due to the lightly cross-linked and flexible polymer network. Moreover, AFM force spectroscopy studies suggest that cross-linker-free microgels constitute of a more homogeneous polymer network than PEG-DA cross-linked particles and have elastic moduli at the particle apex that are ~5 times smaller than the moduli of 5 mol-% PEG-DA cross-linked microgels. Resistive pulse sensing experiments demonstrate that microgels prepared at 75 and 80°C without PEG-DA are able to deform significantly to pass through nanopores that are smaller than the microgel size. Additionally, we found that polymer network flexibility of microgels is a useful tool to control the formation of particle dewetting patterns. This offers a promising new avenue for build-up of 2D self-assembled particle structures with patterned chemical and mechanical properties. PMID:28719648

A Method of Sharing Tacit Knowledge by a Bulletin Board Link to Video Scene and an Evaluation in the Field of Nursing Skill

NASA Astrophysics Data System (ADS)

Shimada, Satoshi; Azuma, Shouzou; Teranaka, Sayaka; Kojima, Akira; Majima, Yukie; Maekawa, Yasuko

We developed the system that knowledge could be discovered and shared cooperatively in the organization based on the SECI model of knowledge management. This system realized three processes by the following method. (1)A video that expressed skill is segmented into a number of scenes according to its contents. Tacit knowledge is shared in each scene. (2)Tacit knowledge is extracted by bulletin board linked to each scene. (3)Knowledge is acquired by repeatedly viewing the video scene with the comment that shows the technical content to be practiced. We conducted experiments that the system was used by nurses working for general hospitals. Experimental results show that the nursing practical knack is able to be collected by utilizing bulletin board linked to video scene. Results of this study confirmed the possibility of expressing the tacit knowledge of nurses' empirical nursing skills sensitively with a clue of video images.

Simulative Analysis of Inter-Satellite Optical Wireless Communication (IsOWC) Link with EDFA

NASA Astrophysics Data System (ADS)

Singh, Mehtab; Singh, Navpreet

2018-04-01

In this paper, simulative analysis and performance comparison of different EDFA (Erbium-doped fiber amplifier) configurations in a 10 Gbps inter-satellite optical wireless communication (IsOWC) link have been reported for a 5,000 km long link and 1,550 nm operating wavelength. The results show that system in which both pre-amplifier and booster amplifier stages are implemented simultaneously outperforms systems with only pre-amplifier and booster amplifier stage. From the results, it can be seen that by deploying a transmission power level of 15 dBm, a link distance of 9,600 km can be achieved with a quality factor of 6.01 dB and BER (Bit error rate) of 1.07×10-9. Also, in this paper, the performance of an 8×7 Gbps WDM-IsOWC link has been reported. The results show that by using both EDFA pre-amplifier and booster amplifier stages, a link distance of 8,000 km for each channel is achievable with desired performance levels (Q≥6 and BER≤10-9). Also, the effect of channel spacing on the performance of WDM-IsOWC link is investigated. The results show that the received signal has acceptable performance levels when the channel spacing is 100 GHz but when the channel spacing is reduced to 80 GHz, the quality of the received signal degrades and link distance decreases.

The Synergy of Double Cross-linking Agents on the Properties of Styrene Butadiene Rubber Foams

PubMed Central

Shao, Liang; Ji, Zhan-You; Ma, Jian-Zhong; Xue, Chao-Hua; Ma, Zhong-Lei; Zhang, Jing

2016-01-01

Sulfur (S) cross-linking styrene butadiene rubber (SBR) foams show high shrinkage due to the cure reversion, leading to reduced yield and increased processing cost. In this paper, double cross-linking system by S and dicumyl peroxide (DCP) was used to decrease the shrinkage of SBR foams. Most importantly, the synergy of double cross-linking agents was reported for the first time to our knowledge. The cell size and its distribution of SBR foams were investigated by FESEM images, which show the effect of DCP content on the cell structure of the SBR foams. The relationships between shrinkage and crystalline of SBR foams were analyzed by the synergy of double cross-linking agents, which were demonstrated by FTIR, Raman spectra, XRD, DSC and TGA. When the DCP content was 0.6 phr, the SBR foams exhibit excellent physical and mechanical properties such as low density (0.223 g/cm3), reduced shrinkage (2.25%) and compression set (10.96%), as well as elevated elongation at break (1.78 × 103%) and tear strength (54.63 N/mm). The results show that these properties are related to the double cross-linking system of SBR foams. Moreover, the double cross-linking SBR foams present high electromagnetic interference (EMI) shielding properties compared with the S cross-linking SBR foams. PMID:27841307

The Synergy of Double Cross-linking Agents on the Properties of Styrene Butadiene Rubber Foams

NASA Astrophysics Data System (ADS)

Shao, Liang; Ji, Zhan-You; Ma, Jian-Zhong; Xue, Chao-Hua; Ma, Zhong-Lei; Zhang, Jing

2016-11-01

Sulfur (S) cross-linking styrene butadiene rubber (SBR) foams show high shrinkage due to the cure reversion, leading to reduced yield and increased processing cost. In this paper, double cross-linking system by S and dicumyl peroxide (DCP) was used to decrease the shrinkage of SBR foams. Most importantly, the synergy of double cross-linking agents was reported for the first time to our knowledge. The cell size and its distribution of SBR foams were investigated by FESEM images, which show the effect of DCP content on the cell structure of the SBR foams. The relationships between shrinkage and crystalline of SBR foams were analyzed by the synergy of double cross-linking agents, which were demonstrated by FTIR, Raman spectra, XRD, DSC and TGA. When the DCP content was 0.6 phr, the SBR foams exhibit excellent physical and mechanical properties such as low density (0.223 g/cm3), reduced shrinkage (2.25%) and compression set (10.96%), as well as elevated elongation at break (1.78 × 103%) and tear strength (54.63 N/mm). The results show that these properties are related to the double cross-linking system of SBR foams. Moreover, the double cross-linking SBR foams present high electromagnetic interference (EMI) shielding properties compared with the S cross-linking SBR foams.

Stop feeling: inhibition of emotional interference following stop-signal trials.

PubMed

Kalanthroff, Eyal; Cohen, Noga; Henik, Avishai

2013-01-01

Although a great deal of literature has been dedicated to the mutual links between emotion and the selective attention component of executive control, there is very little data regarding the links between emotion and the inhibitory component of executive control. In the current study we employed an emotional stop-signal task in order to examine whether emotion modulates and is modulated by inhibitory control. Results replicated previous findings showing reduced inhibitory control [longer stop-signal reaction time (SSRT)] following negative, compared to neutral pictures. Most importantly, results show decreased emotional interference following stop-signal trials. These results show that the inhibitory control component of executive control can serve to decrease emotional effects. We suggest that inhibitory control and emotion have a two-way connection in which emotion disrupts inhibitory control and activation of inhibitory control disrupts emotion.

Phenotypic and genetic overlap between autistic traits at the extremes of the general population.

PubMed

Ronald, Angelica; Happé, Francesca; Price, Thomas S; Baron-Cohen, Simon; Plomin, Robert

2006-10-01

To investigate children selected from a community sample for showing extreme autistic-like traits and to assess the degree to which these individual traits--social impairments (SIs), communication impairments (CIs), and restricted repetitive behaviors and interests (RRBIs)--are caused by genes and environments, whether all of them are caused by the same genes and environments, and how often they occur together (as required by an autism diagnosis). The most extreme-scoring 5% were selected from 3,419 8-year-old pairs in the Twins Early Development Study assessed on the Childhood Asperger Syndrome Test. Phenotypic associations between extreme traits were compared with associations among the full-scale scores. Genetic associations between extreme traits were quantified using bivariate DeFries-Fulker extremes analysis. Phenotypic relationships between extreme SIs, CIs, and RRBIs were modest. There was a degree of genetic overlap between them, but also substantial genetic specificity. This first twin study assessing the links between extreme individual autistic-like traits (SIs, CIs, and RRBIs) found that all are highly heritable but show modest phenotypic and genetic overlap. This finding concurs with that of an earlier study from the same cohort that showed that a total autistic symptoms score at the extreme showed high heritability and that SIs, CIs, and RRBIs show weak links in the general population. This new finding has relevance for both clinical models and future molecular genetic studies.

Structure-property studies of thermoplastic and thermosetting polyurethanes using palm and soya oils-based polyols.

PubMed

Mohammed, Issam Ahmed; Al-Mulla, Emad Abbas Jaffar; Kadar, Nurul Khizien Abdul; Ibrahim, Mazlan

2013-01-01

Palm and soya oils were converted to monoglycerides via transesterification of triglycerides with glycerol by one step process to produce renewable polyols. Thermoplastic polyurethanes (TPPUs) were prepared from the reaction of the monoglycerides which act as polyol with 4,4'-methylenediphenyldiisocyanate (MDI) whereas, thermosetting polyurethanes (TSPUs) were prepared from the reaction of glycerol, MDI and monoglycerides in one pot. Characterization of the polyurethanes was carried out by FT-IR, (1)H NMR, and iodine value and sol-gel fraction. The TSPUs showed good thermal properties compared to TPPUs as well as TSPUs exhibits good properties in pencil hardness and adhesion, however poorer in flexural and impact strength compared to TPPUs. The higher percentage of cross linked fraction, the higher degree of cross linking occurred, which is due to the higher number of double bond presents in the TSPUs. These were reflected in iodine value test as the highest iodine value of the soya-based thermosetting polyurethanes confirmed the highest degree of cross linking. Polyurethanes based on soya oil showed better properties compared to palm oil. This study is a breakthrough development of polyurethane resins using palm and soya oils as one of the raw materials.

What Vaccinations Does My Child Need?

MedlinePlus

... not cause alarm. Some parents are concerned that vaccines might cause autism. However,many studies show that there is no link between getting vaccines and then getting autism. As with any medicine, there is a very ...

Back to Basics: Exploring the Conceptual Basis of Nursing.

ERIC Educational Resources Information Center

Scammell, J.; Miller, S.

1999-01-01

Supports the need for study of the foundational concepts of nursing. Evaluates nursing teachers' experiences in implementing a foundations unit, showing that it raised conceptual awareness and helped students link theory and practice. (SK)

Intentionally Linking Gateway-Course Transformation Efforts with Guided Pathways

ERIC Educational Resources Information Center

Rife, Martine Courant; Conner, Christine

2017-01-01

Offered as a case study, this chapter shows how Lansing Community College intentionally combined efforts to redesign eight high-risk courses with efforts to create clearer guided curricular pathways for the college's students.

Synthesis, Characterisation, and Evaluation of a Cross-Linked Disulphide Amide-Anhydride-Containing Polymer Based on Cysteine for Colonic Drug Delivery

PubMed Central

Lim, Vuanghao; Peh, Kok Khiang; Sahudin, Shariza

2013-01-01

The use of disulphide polymers, a low redox potential responsive delivery, is one strategy for targeting drugs to the colon so that they are specifically released there. The objective of this study was to synthesise a new cross-linked disulphide-containing polymer based on the amino acid cysteine as a colon drug delivery system and to evaluate the efficiency of the polymers for colon targeted drug delivery under the condition of a low redox potential. The disulphide cross-linked polymers were synthesised via air oxidation of 1,2-ethanedithiol and 3-mercapto-N-2-(3-mercaptopropionamide)-3-mercapto propionic anhydride (trithiol monomers) using different ratio combinations. Four types of polymers were synthesised: P10, P11, P151, and P15. All compounds synthesised were characterised by NMR, IR, LC-MS, CHNS analysis, Raman spectrometry, SEM-EDX, and elemental mapping. The synthesised polymers were evaluated in chemical reduction studies that were performed in zinc/acetic acid solution. The suitability of each polymer for use in colon-targeted drug delivery was investigated in vitro using simulated conditions. Chemical reduction studies showed that all polymers were reduced after 0.5–1.0 h, but different polymers had different thiol concentrations. The bacterial degradation studies showed that the polymers were biodegraded in the anaerobic colonic bacterial medium. Degradation was most pronounced for polymer P15. This result complements the general consensus that biodegradability depends on the swellability of polymers in an aqueous environment. Overall, these results suggest that the cross-linked disulphide-containing polymers described herein could be used as coatings for drugs delivered to the colon. PMID:24351841

Quantification of the effect of cross-shear and applied nominal contact pressure on the wear of moderately cross-linked polyethylene.

PubMed

Abdelgaied, Abdellatif; Brockett, Claire L; Liu, Feng; Jennings, Louise M; Fisher, John; Jin, Zhongmin

2013-01-01

Polyethylene wear is a great concern in total joint replacement. It is now considered a major limiting factor to the long life of such prostheses. Cross-linking has been introduced to reduce the wear of ultra-high-molecular-weight polyethylene (UHMWPE). Computational models have been used extensively for wear prediction and optimization of artificial knee designs. However, in order to be independent and have general applicability and predictability, computational wear models should be based on inputs from independent experimentally determined wear parameters (wear factors or wear coefficients). The objective of this study was to investigate moderately cross-linked UHMWPE, using a multidirectional pin-on-plate wear test machine, under a wide range of applied nominal contact pressure (from 1 to 11 MPa) and under five different kinematic inputs, varying from a purely linear track to a maximum rotation of +/- 55 degrees. A computational model, based on a direct simulation of the multidirectional pin-on-plate wear tester, was developed to quantify the degree of cross-shear (CS) of the polyethylene pins articulating against the metallic plates. The moderately cross-linked UHMWPE showed wear factors less than half of that reported in the literature for, the conventional UHMWPE, under the same loading and kinematic inputs. In addition, under high applied nominal contact stress, the moderately crosslinked UHMWPE wear showed lower dependence on the degree of CS compared to that under low applied nominal contact stress. The calculated wear coefficients were found to be independent of the applied nominal contact stress, in contrast to the wear factors that were shown to be highly pressure dependent. This study provided independent wear data for inputs into computational models for moderately cross-linked polyethylene and supported the application of wear coefficient-based computational wear models.

Identification of Kynoxazine, a Novel Fluorescent Product of the Reaction between 3-Hydroxykynurenine and Erythrulose in the Human Lens, and Its Role in Protein Modification*

PubMed Central

Rakete, Stefan; Nagaraj, Ram H.

2016-01-01

Kynurenine pathway metabolites and ascorbate degradation products are present in human lenses. In this study, we showed that erythrulose, a major ascorbate degradation product, reacts spontaneously with 3-hydroxykynurenine to form a fluorescent product. Structural characterization of the product revealed it to be 2-amino-4-(2-hydroxy-3-(2-hydroxyethyl)-2H-benzo[b][1,4]oxazin-5-yl)-4-oxobutanoic acid, which we named kynoxazine. Unlike 3-hydroxykynurenine, 3-hydroxykynurenine glucoside and kynurenine were unable to form a kynoxazine-like compound, which suggested that the aminophenol moiety in 3-hydroxykynurenine is essential for the formation of kynoxazine. This reasoning was confirmed using a model compound, 1-(2-amino-3-hydroxyphenyl)ethan-1-one, which is an aminophenol lacking the amino acid moiety of 3-hydroxykynurenine. Ultra-performance liquid chromatography-tandem mass spectrometry analyses showed that kynoxazine is present in the human lens at levels ranging from 0 to 64 pmol/mg lens. Kynoxazine as well as erythrulose degraded under physiological conditions to generate 3-deoxythreosone, which modified and cross-linked proteins through the formation of an arginine adduct, 3-deoxythreosone-derived hydroimidazolone, and a lysine-arginine cross-linking adduct, 3-deoxythreosone-derived hydroimidazolimine cross-link. Ultra-performance liquid chromatography-tandem mass spectrometry quantification showed that 32–169 pmol/mg protein of 3-deoxythreosone-derived hydroimidazolone and 1.1–11.2 pmol/mg protein of 3-deoxythreosone-derived hydroimidazolimine cross-link occurred in aging lenses. Taken together, these results demonstrate a novel biochemical mechanism by which ascorbate oxidation and the kynurenine pathway intertwine, which could promote protein modification and cross-linking in aging human lenses. PMID:26941078

The Hunt Opinion Model—An Agent Based Approach to Recurring Fashion Cycles

PubMed Central

Apriasz, Rafał; Krueger, Tyll; Marcjasz, Grzegorz; Sznajd-Weron, Katarzyna

2016-01-01

We study a simple agent-based model of the recurring fashion cycles in the society that consists of two interacting communities: “snobs” and “followers” (or “opinion hunters”, hence the name of the model). Followers conform to all other individuals, whereas snobs conform only to their own group and anticonform to the other. The model allows to examine the role of the social structure, i.e. the influence of the number of inter-links between the two communities, as well as the role of the stability of links. The latter is accomplished by considering two versions of the same model—quenched (parameterized by fraction L of fixed inter-links) and annealed (parameterized by probability p that a given inter-link exists). Using Monte Carlo simulations and analytical treatment (the latter only for the annealed model), we show that there is a critical fraction of inter-links, above which recurring cycles occur. For p ≤ 0.5 we derive a relation between parameters L and p that allows to compare both models and show that the critical value of inter-connections, p*, is the same for both versions of the model (annealed and quenched) but the period of a fashion cycle is shorter for the quenched model. Near the critical point, the cycles are irregular and a change of fashion is difficult to predict. For the annealed model we also provide a deeper theoretical analysis. We conjecture on topological grounds that the so-called saddle node heteroclinic bifurcation appears at p*. For p ≥ 0.5 we show analytically the existence of the second critical value of p, for which the system undergoes Hopf’s bifurcation. PMID:27835679

The Hunt Opinion Model-An Agent Based Approach to Recurring Fashion Cycles.

PubMed

Apriasz, Rafał; Krueger, Tyll; Marcjasz, Grzegorz; Sznajd-Weron, Katarzyna

2016-01-01

We study a simple agent-based model of the recurring fashion cycles in the society that consists of two interacting communities: "snobs" and "followers" (or "opinion hunters", hence the name of the model). Followers conform to all other individuals, whereas snobs conform only to their own group and anticonform to the other. The model allows to examine the role of the social structure, i.e. the influence of the number of inter-links between the two communities, as well as the role of the stability of links. The latter is accomplished by considering two versions of the same model-quenched (parameterized by fraction L of fixed inter-links) and annealed (parameterized by probability p that a given inter-link exists). Using Monte Carlo simulations and analytical treatment (the latter only for the annealed model), we show that there is a critical fraction of inter-links, above which recurring cycles occur. For p ≤ 0.5 we derive a relation between parameters L and p that allows to compare both models and show that the critical value of inter-connections, p*, is the same for both versions of the model (annealed and quenched) but the period of a fashion cycle is shorter for the quenched model. Near the critical point, the cycles are irregular and a change of fashion is difficult to predict. For the annealed model we also provide a deeper theoretical analysis. We conjecture on topological grounds that the so-called saddle node heteroclinic bifurcation appears at p*. For p ≥ 0.5 we show analytically the existence of the second critical value of p, for which the system undergoes Hopf's bifurcation.

Preparation and Optimisation of Cross-Linked Enzyme Aggregates Using Native Isolate White Rot Fungi Trametes versicolor and Fomes fomentarius for the Decolourisation of Synthetic Dyes

PubMed Central

Vršanská, Martina; Voběrková, Stanislava; Jiménez Jiménez, Ana María; Strmiska, Vladislav; Adam, Vojtěch

2017-01-01

The key to obtaining an optimum performance of an enzyme is often a question of devising a suitable enzyme and optimisation of conditions for its immobilization. In this study, laccases from the native isolates of white rot fungi Fomes fomentarius and/or Trametes versicolor, obtained from Czech forests, were used. From these, cross-linked enzyme aggregates (CLEA) were prepared and characterised when the experimental conditions were optimized. Based on the optimization steps, saturated ammonium sulphate solution (75 wt.%) was used as the precipitating agent, and different concentrations of glutaraldehyde as a cross-linking agent were investigated. CLEA aggregates formed under the optimal conditions showed higher catalytic efficiency and stabilities (thermal, pH, and storage, against denaturation) as well as high reusability compared to free laccase for both fungal strains. The best concentration of glutaraldehyde seemed to be 50 mM and higher efficiency of cross-linking was observed at a low temperature 4 °C. An insignificant increase in optimum pH for CLEA laccases with respect to free laccases for both fungi was observed. The results show that the optimum temperature for both free laccase and CLEA laccase was 35 °C for T. versicolor and 30 °C for F. fomentarius. The CLEAs retained 80% of their initial activity for Trametes and 74% for Fomes after 70 days of cultivation. Prepared cross-linked enzyme aggregates were also investigated for their decolourisation activity on malachite green, bromothymol blue, and methyl red dyes. Immobilised CLEA laccase from Trametes versicolor showed 95% decolourisation potential and CLEA from Fomes fomentarius demonstrated 90% decolourisation efficiency within 10 h for all dyes used. These results suggest that these CLEAs have promising potential in dye decolourisation. PMID:29295505

Identification of O-Linked Glycoproteins Binding to the Lectin Helix pomatia Agglutinin as Markers of Metastatic Colorectal Cancer

PubMed Central

Peiris, Diluka; Ossondo, Marlène; Fry, Simon; Loizidou, Marilena; Smith-Ravin, Juliette; Dwek, Miriam V.

2015-01-01

Background Protein glycosylation is an important post-translational modification shown to be altered in all tumour types studied to date. Mucin glycoproteins have been established as important carriers of O-linked glycans but other glycoproteins exhibiting altered glycosylation repertoires have yet to be identified but offer potential as biomarkers for metastatic cancer. Methodology In this study a glycoproteomic approach was used to identify glycoproteins exhibiting alterations in glycosylation in colorectal cancer and to evaluate the changes in O-linked glycosylation in the context of the p53 and KRAS (codon 12/13) mutation status. Affinity purification with the carbohydrate binding protein from Helix pomatia agglutinin (HPA) was coupled to 2-dimensional gel electrophoresis with mass spectrometry to enable the identification of low abundance O-linked glycoproteins from human colorectal cancer specimens. Results Aberrant O-linked glycosylation was observed to be an early event that occurred irrespective of the p53 and KRAS status and correlating with metastatic colorectal cancer. Affinity purification using the lectin HPA followed by proteomic analysis revealed annexin 4, annexin 5 and CLCA1 to be increased in the metastatic colorectal cancer specimens. The results were validated using a further independent set of specimens and this showed a significant association between the staining score for annexin 4 and HPA and the time to metastasis; independently (annexin A4: Chi square 11.45, P = 0.0007; HPA: Chi square 9.065, P = 0.0026) and in combination (annexin 4 and HPA combined: Chi square 13.47; P = 0.0002). Conclusion Glycoproteins showing changes in O-linked glycosylation in metastatic colorectal cancer have been identified. The glycosylation changes were independent of p53 and KRAS status. These proteins offer potential for further exploration as biomarkers and potential targets for metastatic colorectal cancer. PMID:26495974

Comparative study on protein cross-linking and gel enhancing effect of microbial transglutaminase on surimi from different fish.

PubMed

Chanarat, Sochaya; Benjakul, Soottawat; H-Kittikun, Aran

2012-03-15

Microbial transglutaminase (MTGase) has been used to increase the gel strength of surimi. Nevertheless, its effectiveness varies with fish species. The aim of this study was to elucidate the effect of MTGase at different levels on protein cross-linking and gel property of surimi from threadfin bream, Indian mackerel and sardine in the presence and absence of endogenous transglutaminase. Breaking force of all surimi gels increased as MTGase levels (0-0.6 U g⁻¹) increased except for threadfin bream surimi gel, where the breaking force decreased at 0.6 U g⁻¹ (P < 0.05). In the presence of EDTA, the gel strengthening effect was lower, suggesting the combined effect of endogenous transglutaminase with MTGase. With the addition of MTGase, the gel with the highest increase in breaking force showed highest decrease in myosin heavy chain. When cross-linking activity of MTGase on natural actomyosin (NAM) was determined, the highest decreasing rate in ε-amino group content with the concomitant increased formation of cross-linked proteins was found in NAM from threadfin bream. The reactivity of muscle proteins toward MTGase-induced cross-linking was in agreement with surimi gel strengthening. The composition and properties of muscle proteins of varying fish species more likely determined protein cross-linking induced by MTGase, thereby affecting their gel properties.

X-inactivation patterns in female Leber`s hereditary optic neuropathy patients do not support a strong X-linked determinant

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

Pegoraro, E.; Hoffman, E.P.; Carelli, V.

1996-02-02

Leber`s hereditary optic neuropathy (LHON) accounts for about 3% of the cases of blindness in young adult males. The underlying mitochondrial pathogenesis of LHON has been well studied, with specific mitochondrial DNA (mtDNA) mutations of structural genes described and well characterized. However, enigmatic aspects of the disease are not explained by mutation data, such as the higher proportion of affected males, the later onset of the disease in females, and the presence of unaffected individuals with a high proportion of mutant mtDNA. A hypothesis which has been put forward to explain the unusual disease expression is a dual model ofmore » mtDNA and X-linked nuclear gene inheritance. If a nuclear X-linked modifier gene influences the expression of the mitochondrial-linked mutant gene then the affected females should be either homozygous for the nuclear determinant, or if heterozygous, lyonization should favor the mutant X. In order to determine if an X-linked gene predisposes to LHON phenotype we studied X-inactivation patterns in 35 females with known mtDNA mutations from 10 LHON pedigrees. Our results do not support a strong X-linked determinant in LHON cause: 2 of the 10 (20%) manifesting carriers showed skewing of X-inactivation, as did 3 of the 25 (12%) nonmanifesting carriers. 39 refs., 2 figs., 1 tab.« less

Long-term effects of ovulation-stimulating drugs on cancer risk.

PubMed

Brinton, Louise

2007-07-01

Although nulliparity has been extensively related to the risk of ovarian, breast and endometrial cancers, with many studies showing the relationship largely attributable to infertility, treatment effects on cancer risk are poorly understood. Two early studies raised substantial concern when ovulation-stimulating drugs were linked with large increases in ovarian cancer, supporting the notion of an important aetiological role of incessant ovulation. Subsequent studies have been mainly reassuring, although some have suggested possible risk increases among nulligravid women, those with extensive follow-up, and those developing borderline tumours. Results regarding effects of fertility drugs on breast cancer risk are conflicting, with some showing no associations and others demonstrating possible risk increases, although for varying subgroups. In contrast, endometrial cancer results are more consistent, with two recent studies showing increased risks related to clomiphene usage. This is of interest given that clomiphene is structurally similar to tamoxifen, a drug extensively linked with this cancer. Given the recent marketing of fertility drugs and the fact that exposed women are only beginning to reach the cancer age range, further follow-up is necessary. This will also be important to fully resolve effects of exposures such as gonadotrophins, used more recently in conjunction with IVF.

Research Links Nutrition to Behavior Disorders.

ERIC Educational Resources Information Center

Schauss, Alexander G.

1985-01-01

Social and medical research studies are examined that show the dramatic effects of biochemical and nutritional factors on antisocial behavior. They include studies of cobalt levels in hair samples of violent and nonviolent criminals, effects of diet on chronic delinquents, and effects of vitamin/mineral supplements on behaviorally disordered…

Purification, Preliminary Characterization and Hepatoprotective Effects of Polysaccharides from Dandelion Root.

PubMed

Cai, Liangliang; Wan, Dongwei; Yi, Fanglian; Luan, Libiao

2017-08-25

In this study, purification, preliminary characterization and hepatoprotective effects of water-soluble polysaccharides from dandelion root (DRP) were investigated. Two polysaccharides, DRP1 and DRP2, were isolated from DRP. The two polysaccharides were α-type polysaccharides and didn't contain protein. DRP1, with a molecular weight of 5695 Da, was composed of glucose, galactose and arabinose, whereas DRP2, with molecular weight of 8882 Da, was composed of rhamnose, galacturonic acid, glucose, galactose and arabinose. The backbone of DRP1 was mainly composed of (1→6)-linked-α-d-Glc and (1→3,4)-linked-α-d-Glc. DRP2 was mainly composed of (1→)-linked-α-d-Ara and (1→)-linked-α-d-Glc. A proof-of-concept study was performed to assess the therapeutic potential of DRP1 and DRP2 in a mouse model that mimics acetaminophen (APAP) -induced liver injury (AILI) in humans. The present study shows DRP1 and DRP2 could protect the liver from APAP-induced hepatic injury by activating the Nrf2-Keap1 pathway. These conclusions demonstrate that the DRP1 and DRP2 might be suitable as functional foods and natural drugs in preventing APAP-induced liver injury.

Immunomodulatory Activity of Dietary Fiber: Arabinoxylan and Mixed-Linked Beta-Glucan Isolated from Barley Show Modest Activities in Vitro

PubMed Central

Samuelsen, Anne Berit; Rieder, Anne; Grimmer, Stine; Michaelsen, Terje E.; Knutsen, Svein H.

2011-01-01

High intake of dietary fiber is claimed to protect against development of colorectal cancer. Barley is a rich source of dietary fiber, and possible immunomodulatory effects of barley polysaccharides might explain a potential protective effect. Dietary fiber was isolated by extraction and enzyme treatment. A mixed-linked β-glucan (WSM-TPX, 96.5% β-glucan, Mw 886 kDa), an arabinoxylan (WUM-BS-LA, 96.4% arabinoxylan, Mw 156 kDa), a mixed-linked β-glucan rich fraction containing 10% arabinoxylan (WSM-TP) and an arabinoxylan rich fraction containing 30% mixed-linked β-glucan (WUM-BS) showed no significant effect on IL-8 secretion and proliferation of two intestinal epithelial cell lines, Caco-2 and HT-29, and had no significant effect on the NF-κB activity in the monocytic cell line U937-3κB-LUC. Further enriched arabinoxylan fractions (WUM-BS-LA) from different barley varieties (Tyra, NK96300, SB94897 and CDCGainer) were less active than the mixed-linked β-glucan rich fractions (WSM-TP and WSM-TPX) in the complement-fixing test. The mixed-linked β-glucan rich fraction from NK96300 and CDCGainer showed similar activities as the positive control while mixed-linked β-glucan rich fractions from Tyra and SB94897 were less active. From these results it is concluded that the isolated high molecular weight mixed-linked β-glucans and arabinoxylans from barley show low immunological responses in selected in vitro test systems and thus possible anti-colon cancer effects of barley dietary fiber cannot be explained by our observations. PMID:21340001

[The link between periodontitis and pancreatic cancer - review of the literature].

PubMed

Haładyj, Anna; Kaczyński, Tomasz; Górska, Renata

2016-01-01

Recent studies suggest that there is a plausible correlation between periodontitis and its influence on general health. By increasing systemic inflammatory response, which does not expire as long as inflammation of periodontal tissue endures, periodontal diseases may induce the increased risk of systemic diseases. Studies found a positive correlation between periodontitis and its impact on development of pancreatic cancer. The relationship between inflammatory periodontal disease and an increased risk of pancreatic cancer is not yet fully understood, therefore, further researches are warranted. The paper discusses the potential mechanisms that combine both entities and affect each other. It also presents results of recent studies showing a link between periodontitis and an increased risk of pancreatic cancer.

Exploring a new jellyfish collagen in the production of microparticles for protein delivery.

PubMed

Calejo, M Teresa; Almeida, António J; Fernandes, Ana I

2012-01-01

A microparticulate protein delivery system was developed using collagen, from the medusa Catostylus tagi, as a polymeric matrix. Collagen microparticles (CMPs) were produced by an emulsification-gelation-solvent extraction method and a high loading efficiency was found for the entrapment of lysozyme and α-lactalbumin. CMPs were cross-linked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). The uncross-linked CMPs were spherical, rough-surfaced, presenting an estimated median size of 28 µm by laser diffraction. Upon cross-linking, particle size (9.5 µm) and size distribution were reduced. CMPs showed a moderate hydrophobic behaviour and a positive surface charge. Cross-linking also resulted in greater stability in water, allowing a slow release, as shown by in vitro experiments. The assessment of lysozyme's biological activity showed that the protein remained active throughout the encapsulation and cross-linking processes. In summary, the work herein described shows the potential use of a marine collagen in the production of microparticles for the controlled release of therapeutic proteins.

Ultrastable optical frequency dissemination on a multi-access fibre network

NASA Astrophysics Data System (ADS)

Bercy, Anthony; Lopez, Olivier; Pottie, Paul-Eric; Amy-Klein, Anne

2016-07-01

We report a laboratory demonstration of the dissemination of an ultrastable optical frequency signal to two distant users simultaneously using a branching network. The ultrastable signal is extracted along a main fibre link; it is optically tracked by a narrow linewidth laser diode, which light is injected in a secondary link. The propagation noise of both links is actively compensated. We implement this scheme with two links of 50-km fibre spools, the extraction being set up at the mid-point of the main link. We show that the extracted signal at the end of the secondary link exhibits a fractional frequency instability of 1.4 × 10-15 at 1-s measurement time, almost equal to the 1.3 × 10-15 instability of the main link output end. The long-term instabilities are also very similar, at a level of 3-5 × 10-20 at 3 × 104-s integration time. We also show that the setting up of this extraction device, or of a simpler one, at the main link input, can test the proper functioning of the noise rejection on this main link. This work is a significant step towards a robust and flexible ultrastable network for multi-users dissemination.

Preparation and characterization of safe microparticles based on xylan.

PubMed

Cartaxo da Costa Urtiga, Silvana; Aquino Azevedo de Lucena Gabi, Camilla; Rodrigues de Araújo Eleamen, Giovanna; Santos Souza, Bartolomeu; Pessôa, Hilzeth de Luna Freire; Marcelino, Henrique Rodrigues; Afonso de Moura Mendonça, Elisângela; Egito, Eryvaldo Sócrates Tabosa do; Oliveira, Elquio Eleamen

2017-10-01

This work describes the preparation and evaluation of safe xylan-based microparticles prepared by cross-linking polymerization using sodium trimetaphosphate. The resulting microparticles were evaluated for morphology, particle size, polymer-cross-link agent interaction, and in vitro toxicity. The microparticles showed narrow monodisperse size distributions with their mean sizes being between 3.5 and 12.5 µm in dried state. FT-IR analyzes confirmed the interaction between sodium trimetaphosphate and xylan during the cross-linking process with formation of phosphate ester bonds. Additionally, the X-ray diffraction patterns and FT-IR analyzes suggested that little or no cross-linking agent remained inside the microparticles. Furthermore, the in-vitro studies using Artemia salina and human erythrocytes revealed that the microparticles are not toxic. Therefore, the overall results suggest that these xylan microparticles can be used as a platform for new drug delivery system.

A novel broad specificity fucosidase capable of core α1-6 fucose release from N-glycans labeled with urea-linked fluorescent dyes.

PubMed

Vainauskas, Saulius; Kirk, Charlotte H; Petralia, Laudine; Guthrie, Ellen P; McLeod, Elizabeth; Bielik, Alicia; Luebbers, Alex; Foster, Jeremy M; Hokke, Cornelis H; Rudd, Pauline M; Shi, Xiaofeng; Taron, Christopher H

2018-06-22

Exoglycosidases are often used for detailed characterization of glycan structures. Bovine kidney α-fucosidase is commonly used to determine the presence of core α1-6 fucose on N-glycans, an important modification of glycoproteins. Recently, several studies have reported that removal of core α1-6-linked fucose from N-glycans labeled with the reactive N-hydroxysuccinimide carbamate fluorescent labels 6-aminoquinolyl-N-hydroxysuccinimidylcarbamate (AQC) and RapiFluor-MS is severely impeded. We report here the cloning, expression and biochemical characterization of an α-fucosidase from Omnitrophica bacterium (termed fucosidase O). We show that fucosidase O can efficiently remove α1-6- and α1-3-linked core fucose from N-glycans. Additionally, we demonstrate that fucosidase O is able to efficiently hydrolyze core α1-6-linked fucose from N-glycans labeled with any of the existing NHS-carbamate activated fluorescent dyes.

Development of Middle Stone Age innovation linked to rapid climate change

PubMed Central

Ziegler, Martin; Simon, Margit H.; Hall, Ian R.; Barker, Stephen; Stringer, Chris; Zahn, Rainer

2013-01-01

The development of modernity in early human populations has been linked to pulsed phases of technological and behavioural innovation within the Middle Stone Age of South Africa. However, the trigger for these intermittent pulses of technological innovation is an enigma. Here we show that, contrary to some previous studies, the occurrence of innovation was tightly linked to abrupt climate change. Major innovational pulses occurred at times when South African climate changed rapidly towards more humid conditions, while northern sub-Saharan Africa experienced widespread droughts, as the Northern Hemisphere entered phases of extreme cooling. These millennial-scale teleconnections resulted from the bipolar seesaw behaviour of the Atlantic Ocean related to changes in the ocean circulation. These conditions led to humid pulses in South Africa and potentially to the creation of favourable environmental conditions. This strongly implies that innovational pulses of early modern human behaviour were climatically influenced and linked to the adoption of refugia. PMID:23695699

Human face structure correlates with professional baseball performance: insights from professional Japanese baseball players.

PubMed

Tsujimura, Hikaru; Banissy, Michael J

2013-06-23

In our daily lives, we use faces as a major source of information about other people. Recent work has begun to highlight how one's facial width-to-height ratio (fWHR) is linked to a number of behaviours (e.g. deception, aggression and financial performance in firms). fWHR has also been linked to several factors that may be beneficial for sport (e.g. achievement drive, winning mentality and aggression). Despite this, few studies have examined the relationship between fWHR and sports performance, and these have focused on Caucasian sportsmen. Here, we investigated the relationship between fWHR and baseball performance in professional Japanese baseball players. We show that fWHR is positively related with home run performance across two consecutive seasons. The findings provide the first evidence linking fWHR to baseball performance and linking fWHR to behavioural outcomes in Asian participants.

Development of Middle Stone Age innovation linked to rapid climate change.

PubMed

Ziegler, Martin; Simon, Margit H; Hall, Ian R; Barker, Stephen; Stringer, Chris; Zahn, Rainer

2013-01-01

The development of modernity in early human populations has been linked to pulsed phases of technological and behavioural innovation within the Middle Stone Age of South Africa. However, the trigger for these intermittent pulses of technological innovation is an enigma. Here we show that, contrary to some previous studies, the occurrence of innovation was tightly linked to abrupt climate change. Major innovational pulses occurred at times when South African climate changed rapidly towards more humid conditions, while northern sub-Saharan Africa experienced widespread droughts, as the Northern Hemisphere entered phases of extreme cooling. These millennial-scale teleconnections resulted from the bipolar seesaw behaviour of the Atlantic Ocean related to changes in the ocean circulation. These conditions led to humid pulses in South Africa and potentially to the creation of favourable environmental conditions. This strongly implies that innovational pulses of early modern human behaviour were climatically influenced and linked to the adoption of refugia.

Phase Diagram of the Bose Hubbard Model with Weak Links

NASA Astrophysics Data System (ADS)

Hettiarachchilage, Kalani; Rousseau, Valy; Tam, Ka-Ming; Moreno, Juana; Jarrell, Mark; Sheehy, Daniel

2012-02-01

We study the ground state phase diagram of strongly interacting ultracold Bose gas in a one-dimensional optical lattice with a tunable weak link, by means of Quantum Monte Carlo simulation. This model contains an on-site repulsive interaction (U) and two different near-neighbor hopping terms, J and t, for the weak link and the remainder of the chain, respectively. We show that by reducing the strength of J, a novel intermediate phase develops which is compressible and non-superfluid. This novel phase is identified as a Normal Bose Liquid (NBL) which does not appear in the phase diagram of the homogeneous bosonic Hubbard model. Further, we find a linear variation of the phase boundary of Normal Bose Liquid (NBL) to SuperFluid (SF) as a function of the strength of the weak link. These results may provide a new path to design advanced atomtronic devices in the future.

Carbon emission trading system of China: a linked market vs. separated markets

NASA Astrophysics Data System (ADS)

Liu, Yu; Feng, Shenghao; Cai, Songfeng; Zhang, Yaxiong; Zhou, Xiang; Chen, Yanbin; Chen, Zhanming

2013-12-01

The Chinese government intends to upgrade its current provincial carbon emission trading pilots to a nationwide scheme by 2015. This study investigates two of scenarios: separated provincial markets and a linked inter-provincial market. The carbon abatement effects of separated and linked markets are compared using two pilot provinces of Hubei and Guangdong based on a computable general equilibrium model termed Sino-TERMCo2. Simulation results show that the linked market can improve social welfare and reduce carbon emission intensity for the nation as well as for the Hubei-Guangdong bloc compared to the separated market. However, the combined system also distributes welfare more unevenly and thus increases social inequity. On the policy ground, the current results suggest that a well-constructed, nationwide carbon market complemented with adequate welfare transfer policies can be employed to replace the current top-down abatement target disaggregation practice.

Physical properties and biocompatibility of chitosan/soy blended membranes.

PubMed

Silva, S S; Santos, M I; Coutinho, O P; Mano, J F; Reis, R L

2005-06-01

Blends of polysaccharides and proteins are a source for the development of novel materials with interesting and tailorable properties, with potential to be used in a range of biomedical applications. in this work a series of blended membranes composed by chitosan and soy protein isolate was prepared by solvent casting methodology. in addition, cross-linking was performed in situ with glutaraldehyde solutions in the range 5x10(-3)-0.1 M. Furthermore, the influence of the composition and cross-linking on the degradation behaviour, water uptake and cell adhesion was investigated. The obtained results showed that the incorporation of chitosan, associated to network formation by cross linking, promoted a slight decrease of water absorption and a slower degradability of the membranes. Moreover, direct contact biocompatibility studies, with L929 cells, indicate that the cross-linking enhances the capability of the material to support cell growth.

A genome-wide systems analysis reveals strong link between colorectal cancer and trimethylamine N-oxide (TMAO), a gut microbial metabolite of dietary meat and fat.

PubMed

Xu, Rong; Wang, QuanQiu; Li, Li

2015-01-01

Dietary intakes of red meat and fat are established risk factors for both colorectal cancer (CRC) and cardiovascular disease (CVDs). Recent studies have shown a mechanistic link between TMAO, an intestinal microbial metabolite of red meat and fat, and risk of CVDs. Data linking TMAO directly to CRC is, however, lacking. Here, we present an unbiased data-driven network-based systems approach to uncover a potential genetic relationship between TMAO and CRC. We constructed two different epigenetic interaction networks (EINs) using chemical-gene, disease-gene and protein-protein interaction data from multiple large-scale data resources. We developed a network-based ranking algorithm to ascertain TMAO-related diseases from EINs. We systematically analyzed disease categories among TMAO-related diseases at different ranking cutoffs. We then determined which genetic pathways were associated with both TMAO and CRC. We show that CVDs and their major risk factors were ranked highly among TMAO-related diseases, confirming the newly discovered mechanistic link between CVDs and TMAO, and thus validating our algorithms. CRC was ranked highly among TMAO-related disease retrieved from both EINs (top 0.02%, #1 out of 4,372 diseases retrieved based on Mendelian genetics and top 10.9% among 882 diseases based on genome-wide association genetics), providing strong supporting evidence for our hypothesis that TMAO is genetically related to CRC. We have also identified putative genetic pathways that may link TMAO to CRC, which warrants further investigation. Through systematic disease enrichment analysis, we also demonstrated that TMAO is related to metabolic syndromes and cancers in general. Our genome-wide analysis demonstrates that systems approaches to studying the epigenetic interactions among diet, microbiome metabolisms, and disease genetics hold promise for understanding disease pathogenesis. Our results show that TMAO is genetically associated with CRC. This study suggests that TMAO may be an important intermediate marker linking dietary meat and fat and gut microbiota metabolism to risk of CRC, underscoring opportunities for the development of new gut microbiome-dependent diagnostic tests and therapeutics for CRC.

Links between personality, time perspective, and intention to practice physical activity during cancer treatment: an exploratory study.

PubMed

Villaron, Charlène; Marqueste, Tanguy; Eisinger, François; Cappiello, Maria-Antonietta; Therme, Pierre; Cury, François

2017-04-01

The purpose of the study was to analyze links between personality, time perspective, and intention to practice physical activity during cancer treatment. One hundred forty-three patients participated in survey by questionnaire. Intention to practice physical activity, time perspective using Zimbardo Time Perspective Inventory, and personality with the Big Five Inventory were measured. Structural equation models using Lisrel were developed to examine hypothetical links between the variables. The adjusted model evidenced an excellent fit (comparative fit index = 0.92; root-mean-square error of approximation = 0.076; P = .014). Results showed that intention to practice exercise was positively linked with openness to experience and negatively with present fatalist time perspective. Moreover, conscientiousness and neuroticism were found to be linked with future time perspective, which was positively related with intention to practice physical activity. The present exploratory study with patients suffering from cancer underlined the importance of considering jointly time perspective dimensions and personality factors for health behavior recommendations. Based on our results, we propose some reflections on practice to help nurses and physicians increase patient's motivation to be physically active. Taking into account patients' personality and time perspective, we would be able to propose specific awareness messages and offer short interventions to have an impact on patients' motivation to practice. Copyright © 2016 John Wiley & Sons, Ltd.

Rheological characterization of cataplasm bases composed of cross-linked partially neutralized polyacrylate hydrogel.

PubMed

Wang, Jian; Zhang, Hongqin; An, Dianyun; Yu, Jian; Li, Wei; Shen, Teng; Wang, Jianxin

2014-10-01

Viscoelasticity is a useful parameter for characterizing the intrinsic properties of the cross-linked polyacrylate hydrogel used in cataplasm bases. The aim of this study was to investigate the effects of various formulation parameters on the rheological characteristics of polyacrylate hydrogel. The hydrogel layers were formed using a partially neutralized polyacrylate (Viscomate(™)), which contained acrylic acid and sodium acrylate in different copolymerization ratios, as the cross-linked gel framework. Dihydroxyaluminum aminoacetate (DAAA), which produces aluminum ions, was used as the cross-linking agent. Rheological analyses were performed using a "stress amplitude sweep" and a "frequency sweep". The results showed that greater amounts of acrylic acid in the structure of Viscomate as well as higher concentrations of DAAA and Viscomate led to an increase in the elastic modulus (G'). However, greater amounts of acrylic acid in the structure of Viscomate and higher concentrations of DAAA had an opposite on the viscous modulus (G″); this might be owing to higher steric hindrance. The results of this study can serve as guidelines for the optimization of formulations for cataplasms.

Localization/delocalization of charges in bay-linked perylene bisimides.

PubMed

Jiang, Wei; Xiao, Chengyi; Hao, Linxiao; Wang, Zhaohui; Ceymann, Harald; Lambert, Christoph; Di Motta, Simone; Negri, Fabrizia

2012-05-29

The copper-mediated Ullmann coupling of 1,7-dibromoperylene bisimides afforded structurally perfect singly-linked perylene bisimide (PBI) arrays, whilst the homo-coupling of 1,12-dibromoperylene bisimides gave doubly-linked and triply-linked diperylene bisimides. The interactions of three bay-linked diperylene bisimides that differed in their linkage (singly, doubly, and triply) were investigated in their neutral and reduced forms (mono-anion to tetra-anion). UV/Vis absorption and fluorescence spectroscopy revealed different degrees of interaction, which was explained by exciton coupling and conjugation effects. The electrochemical properties and spectroelectrochemistry also showed quite-different degrees of PBI interactions in the reduced mixed-valence species, which was apparent by the observation of CT bands. The interpretation of the experimental findings was supported by spin-restricted and -unrestricted DFT and time-dependent TD-DFT calculations with the long-range-corrected CAM-B3LYP functional. Accordingly, the degree of interaction in both the neutral and reduced forms of the bay-linked PBIs was qualitatively in the order doubly linked

Sequence-Level Mechanisms of Human Epigenome Evolution

PubMed Central

Prendergast, James G.D.; Chambers, Emily V.; Semple, Colin A.M.

2014-01-01

DNA methylation and chromatin states play key roles in development and disease. However, the extent of recent evolutionary divergence in the human epigenome and the influential factors that have shaped it are poorly understood. To determine the links between genome sequence and human epigenome evolution, we examined the divergence of DNA methylation and chromatin states following segmental duplication events in the human lineage. Chromatin and DNA methylation states were found to have been generally well conserved following a duplication event, with the evolution of the epigenome largely uncoupled from the total number of genetic changes in the surrounding DNA sequence. However, the epigenome at tissue-specific, distal regulatory regions was observed to be unusually prone to diverge following duplication, with particular sequence differences, altering known sequence motifs, found to be associated with divergence in patterns of DNA methylation and chromatin. Alu elements were found to have played a particularly prominent role in shaping human epigenome evolution, and we show that human-specific AluY insertion events are strongly linked to the evolution of the DNA methylation landscape and gene expression levels, including at key neurological genes in the human brain. Studying paralogous regions within the same sample enables the study of the links between genome and epigenome evolution while controlling for biological and technical variation. We show DNA methylation and chromatin divergence between duplicated regions are linked to the divergence of particular genetic motifs, with Alu elements having played a disproportionate role in the evolution of the epigenome in the human lineage. PMID:24966180

Bias in the Flesh: Skin Complexion and Stereotype Consistency in Political Campaigns.

PubMed

Messing, Solomon; Jabon, Maria; Plaut, Ethan

2016-01-01

There is strong evidence linking skin complexion to negative stereotypes and adverse real-world outcomes. We extend these findings to political ad campaigns, in which skin complexion can be easily manipulated in ways that are difficult to detect. Devising a method to measure how dark a candidate appears in an image, this paper examines how complexion varied with ad content during the 2008 presidential election campaign (study 1). Findings show that darker images were more frequent in negative ads-especially those linking Obama to crime-which aired more frequently as Election Day approached. We then conduct an experiment to document how these darker images can activate stereotypes, and show that a subtle darkness manipulation is sufficient to activate the most negative stereotypes about Blacks-even when the candidate is a famous counter-stereotypical exemplar-Barack Obama (study 2). Further evidence of an evaluative penalty for darker skin comes from an observational study measuring affective responses to depictions of Obama with varying skin complexion, presented via the Affect Misattribution Procedure in the 2008 American National Election Study (study 3). This study demonstrates that darker images are used in a way that complements ad content, and shows that doing so can negatively affect how individuals evaluate candidates and think about politics.

BacNet and Analog/Digital Interfaces of the Building Controls Virtual Testbed

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

Nouidui, Thierry Stephane; Wetter, Michael; Li, Zhengwei

2011-11-01

This paper gives an overview of recent developments in the Building Controls Virtual Test Bed (BCVTB), a framework for co-simulation and hardware-in-the-loop. First, a general overview of the BCVTB is presented. Second, we describe the BACnet interface, a link which has been implemented to couple BACnet devices to the BCVTB. We present a case study where the interface was used to couple a whole building simulation program to a building control system to assess in real-time the performance of a real building. Third, we present the ADInterfaceMCC, an analog/digital interface that allows a USB-based analog/digital converter to be linked tomore » the BCVTB. In a case study, we show how the link was used to couple the analog/digital converter to a building simulation model for local loop control.« less

Dissecting the links between cerebellum and dystonia.

PubMed

Malone, Ailish; Manto, Mario; Hass, Chris

2014-12-01

Dystonia is a common movement disorder characterized by sustained muscle contractions. These contractions generate twisting and repetitive movements or typical abnormal postures, often exacerbated by voluntary movement. Dystonia can affect almost all the voluntary muscles. For several decades, the discussion on the pathogenesis has been focused on basal ganglia circuits, especially striatal networks. So far, although dystonia has been observed in some forms of ataxia such as dominant ataxias, the link between the cerebellum and dystonia has remained unclear. Recent human studies and experimental data mainly in rodents show that the cerebellum circuitry could also be a key player in the pathogenesis of some forms of dystonia. In particular, studies based on behavioral adaptation paradigm shed light on the links between dystonia and cerebellum. The spectrum of movement disorders in which the cerebellum is implicated is continuously expanding, and manipulation of cerebellar circuits might even emerge as a candidate therapy in the coming years.

A Study of an Optical Lunar Surface Communications Network with High Bandwidth Direct to Earth Link

NASA Technical Reports Server (NTRS)

Wilson, K.; Biswas, A.; Schoolcraft, J.

2011-01-01

A lunar surface systems study explores the application of optical communications to support a high bandwidth data link from a lunar relay satellite and from fixed lunar assets. The results show that existing 1-m ground stations could provide more than 99% coverage of the lunar terminal at 100Mb/s data rates from a lunar relay satellite and in excess of 200Mb/s from a fixed terminal on the lunar surface. We have looked at the effects of the lunar regolith and its removal on optical samples. Our results indicate that under repeated dust removal episodes sapphire rather than fused silica would be a more durable material for optical surfaces. Disruption tolerant network protocols can minimize the data loss due to link dropouts. We report on the preliminary results of the DTN protocol implemented over the optical carrier.

Understanding the science-learning environment: A genetically sensitive approach.

PubMed

Haworth, Claire M A; Davis, Oliver S P; Hanscombe, Ken B; Kovas, Yulia; Dale, Philip S; Plomin, Robert

2013-02-01

Previous studies have shown that environmental influences on school science performance increase in importance from primary to secondary school. Here we assess for the first time the relationship between the science-learning environment and science performance using a genetically sensitive approach to investigate the aetiology of this link. 3000 pairs of 14-year-old twins from the UK Twins Early Development Study reported on their experiences of the science-learning environment and were assessed for their performance in science using a web-based test of scientific enquiry. Multivariate twin analyses were used to investigate the genetic and environmental links between environment and outcome. The most surprising result was that the science-learning environment was almost as heritable (43%) as performance on the science test (50%), and showed negligible shared environmental influence (3%). Genetic links explained most (56%) of the association between learning environment and science outcome, indicating gene-environment correlation.

Structure, chain conformation and antitumor activity of a novel polysaccharide from Lentinus edodes.

PubMed

Yu, Zhang; Ming, Gu; Kaiping, Wang; Zhixiang, Chen; Liquan, Dai; Jingyu, Liu; Fang, Zeng

2010-12-01

A water-soluble polysaccharide LT1 was isolated from the basidiocarps of Lentinus edodes by hot water extraction and ethanol precipitations, further purified by gel chromatography. The Mw of LT1 was estimated to be 642 kDa by using HPGPC. Chemical and spectroscopic studies illustrated that LT1 has a backbone chain composed of 1 → 4-linked and 1 → 3-linked glucopyranosyl residues and has branches of single glucosyl stubs at C-6 of β-(1 → 4)-linked glucopyranosyl. AFM and Congo-red test revealed that LT1 existed as triple helix chain in 0.10 M NaOH solution or distilled water. Our studies showed that LT1 presented significant antitumor bioactivities on Sarcoma180 solid tumor cell implanted in BALB/c mice, which implies that LT1 could be potentially applied as a natural antitumor drug. Copyright © 2010 Elsevier B.V. All rights reserved.

The alliance relationship analysis of international terrorist organizations with link prediction

NASA Astrophysics Data System (ADS)

Fang, Ling; Fang, Haiyang; Tian, Yanfang; Yang, Tinghong; Zhao, Jing

2017-09-01

Terrorism is a huge public hazard of the international community. Alliances of terrorist organizations may cause more serious threat to national security and world peace. Understanding alliances between global terrorist organizations will facilitate more effective anti-terrorism collaboration between governments. Based on publicly available data, this study constructed a alliance network between terrorist organizations and analyzed the alliance relationships with link prediction. We proposed a novel index based on optimal weighted fusion of six similarity indices, in which the optimal weight is calculated by genetic algorithm. Our experimental results showed that this algorithm could achieve better results on the networks than other algorithms. Using this method, we successfully digged out 21 real terrorist organizations alliance from current data. Our experiment shows that this approach used for terrorist organizations alliance mining is effective and this study is expected to benefit the form of a more powerful anti-terrorism strategy.

The role of motor simulation in action perception: a neuropsychological case study.

PubMed

Eskenazi, Terry; Grosjean, Marc; Humphreys, Glyn W; Knoblich, Guenther

2009-07-01

Research on embodied cognition stresses that bodily and motor processes constrain how we perceive others. Regarding action perception the most prominent hypothesis is that observed actions are matched to the observer's own motor representations. Previous findings demonstrate that the motor laws that constrain one's performance also constrain one's perception of others' actions. The present neuropsychological case study asked whether neurological impairments affect a person's performance and action perception in the same way. The results showed that patient DS, who suffers from a frontal brain lesion, not only ignored target size when performing movements but also when asked to judge whether others can perform the same movements. In other words DS showed the same violation of Fitts's law when performing and observing actions. These results further support the assumption of close perception action links and the assumption that these links recruit predictive mechanisms residing in the motor system.

Two new templates for epidemiology applications: linked micromap plots and conditioned choropleth maps.

PubMed

Carr, D B; Wallin, J F; Carr, D A

This paper describes two interactive templates for representing spatially indexed estimates. Both templates use a matrix layout of small panels. The first template, called linked micromap plots, can represent multivariate estimates associated with each spatially indexed study unit. The second template, called conditioned choropleth maps, shows the connection between a dependent variable, as represented in a classed choropleth map, and two explanatory variables. The paper describes the cognitive considerations that motivate the layouts and representation details. The discussion also addresses topics of data quality and access, hypothesis generation, and interactive features such as pan and zoom and dynamic conditioning via sliders. The examples show epidemiological (mortality rates) and environmental (toxic concentrations) applications. Copyright 2000 John Wiley & Sons, Ltd.

Linearity optimizations of analog ring resonator modulators through bias voltage adjustments

NASA Astrophysics Data System (ADS)

Hosseinzadeh, Arash; Middlebrook, Christopher T.

2018-03-01

The linearity of ring resonator modulator (RRM) in microwave photonic links is studied in terms of instantaneous bandwidth, fabrication tolerances, and operational bandwidth. A proposed bias voltage adjustment method is shown to maximize spur-free dynamic range (SFDR) at instantaneous bandwidths required by microwave photonic link (MPL) applications while also mitigating RRM fabrication tolerances effects. The proposed bias voltage adjustment method shows RRM SFDR improvement of ∼5.8 dB versus common Mach-Zehnder modulators at 500 MHz instantaneous bandwidth. Analyzing operational bandwidth effects on SFDR shows RRMs can be promising electro-optic modulators for MPL applications which require high operational frequencies while in a limited bandwidth such as radio-over-fiber 60 GHz wireless network access.

Intracellular NAD+ levels are associated with LPS-induced TNF-α release in pro-inflammatory macrophages

PubMed Central

Al-Shabany, Abbas Jawad; Moody, Alan John; Foey, Andrew David; Billington, Richard Andrew

2016-01-01

Metabolism and immune responses have been shown to be closely linked and as our understanding increases, so do the intricacies of the level of linkage. NAD+ has previously been shown to regulate tumour necrosis factor-α (TNF-α) synthesis and TNF-α has been shown to regulate NAD+ homoeostasis providing a link between a pro-inflammatory response and redox status. In the present study, we have used THP-1 differentiation into pro- (M1-like) and anti- (M2-like) inflammatory macrophage subset models to investigate this link further. Pro- and anti-inflammatory macrophages showed different resting NAD+ levels and expression levels of NAD+ homoeostasis enzymes. Challenge with bacterial lipopolysaccharide, a pro-inflammatory stimulus for macrophages, caused a large, biphasic and transient increase in NAD+ levels in pro- but not anti-inflammatory macrophages that were correlated with TNF-α release and inhibition of certain NAD+ synthesis pathways blocked TNF-α release. Lipopolysaccharide stimulation also caused changes in mRNA levels of some NAD+ homoeostasis enzymes in M1-like cells. Surprisingly, despite M2-like cells not releasing TNF-α or changing NAD+ levels in response to lipopolysaccharide, they showed similar mRNA changes compared with M1-like cells. These data further strengthen the link between pro-inflammatory responses in macrophages and NAD+. The agonist-induced rise in NAD+ shows striking parallels to well-known second messengers and raises the possibility that NAD+ is acting in a similar manner in this model. PMID:26764408

Modeling Protein Excited-state Structures from "Over-length" Chemical Cross-links.

PubMed

Ding, Yue-He; Gong, Zhou; Dong, Xu; Liu, Kan; Liu, Zhu; Liu, Chao; He, Si-Min; Dong, Meng-Qiu; Tang, Chun

2017-01-27

Chemical cross-linking coupled with mass spectroscopy (CXMS) provides proximity information for the cross-linked residues and is used increasingly for modeling protein structures. However, experimentally identified cross-links are sometimes incompatible with the known structure of a protein, as the distance calculated between the cross-linked residues far exceeds the maximum length of the cross-linker. The discrepancies may persist even after eliminating potentially false cross-links and excluding intermolecular ones. Thus the "over-length" cross-links may arise from alternative excited-state conformation of the protein. Here we present a method and associated software DynaXL for visualizing the ensemble structures of multidomain proteins based on intramolecular cross-links identified by mass spectrometry with high confidence. Representing the cross-linkers and cross-linking reactions explicitly, we show that the protein excited-state structure can be modeled with as few as two over-length cross-links. We demonstrate the generality of our method with three systems: calmodulin, enzyme I, and glutamine-binding protein, and we show that these proteins alternate between different conformations for interacting with other proteins and ligands. Taken together, the over-length chemical cross-links contain valuable information about protein dynamics, and our findings here illustrate the relationship between dynamic domain movement and protein function. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Perception and Cognition in the Ageing Brain: A Brief Review of the Short- and Long-Term Links between Perceptual and Cognitive Decline

PubMed Central

Roberts, Katherine L.; Allen, Harriet A.

2016-01-01

Ageing is associated with declines in both perception and cognition. We review evidence for an interaction between perceptual and cognitive decline in old age. Impoverished perceptual input can increase the cognitive difficulty of tasks, while changes to cognitive strategies can compensate, to some extent, for impaired perception. While there is strong evidence from cross-sectional studies for a link between sensory acuity and cognitive performance in old age, there is not yet compelling evidence from longitudinal studies to suggest that poor perception causes cognitive decline, nor to demonstrate that correcting sensory impairment can improve cognition in the longer term. Most studies have focused on relatively simple measures of sensory (visual and auditory) acuity, but more complex measures of suprathreshold perceptual processes, such as temporal processing, can show a stronger link with cognition. The reviewed evidence underlines the importance of fully accounting for perceptual deficits when investigating cognitive decline in old age. PMID:26973514

An Effective Approach to Violence Prevention: Traditional Martial Arts in Middle School.

ERIC Educational Resources Information Center

Zivin, Gail; Hassan, Nimr R.; DePaula, Geraldine F.; Monti, Daniel A.; Harlan, Carmen; Hossain, Kashfia D.; Patterson, Ksai

2001-01-01

Replicated and extended the design and outcome measures of several small studies. In these studies, juveniles at high risk for violence and delinquency showed decreased violence and positive changes in psychological risk factors after being required to take a school-linked course in traditional martial arts. (Author)

Spatial attention interacts with serial-order retrieval from verbal working memory.

PubMed

van Dijck, Jean-Philippe; Abrahamse, Elger L; Majerus, Steve; Fias, Wim

2013-09-01

The ability to maintain the serial order of events is recognized as a major function of working memory. Although general models of working memory postulate a close link between working memory and attention, such a link has so far not been proposed specifically for serial-order working memory. The present study provided the first empirical demonstration of a direct link between serial order in verbal working memory and spatial selective attention. We show that the retrieval of later items of a sequence stored in working memory-compared with that of earlier items-produces covert attentional shifts toward the right. This observation suggests the conceptually surprising notion that serial-order working memory, even for nonspatially defined verbal items, draws on spatial attention.

Numbers and space: associations and dissociations.

PubMed

Nathan, Merav Ben; Shaki, Samuel; Salti, Moti; Algom, Daniel

2009-06-01

A cornerstone of contemporary research in numerical cognition is the surprising link found between numbers and space. In particular, people react faster and more accurately to small numbers with a left-hand key and to large numbers with a right-hand key. Because this contingency is found in a variety of tasks, it has been taken to support the automatic activation of magnitude as well as the notion of a mental number line arranged from left to right. The present study challenges the presence of a link between left-right location, on the one hand, and small-large number, on the other hand. We show that a link exists between space and relative magnitude, a relationship that might or might not be unique to numbers.

Reentrant behaviour in polyvinyl alcohol-borax hydrogels

NASA Astrophysics Data System (ADS)

Lawrence, Mathias B.; Desa, J. A. E.; Aswal, V. K.

2018-01-01

Polyvinyl alcohol (PVA) hydrogels, cross-linked with varying concentrations of borax, were studied with small angle neutron scattering (SANS), x-ray diffraction (XRD) and differential thermal analysis (DTA). The SANS data satisfy the Ornstein-Zernike approximation. The hydrogels are modelled as PVA chains bound by borate cross-links. Water occupies the spaces within the three-dimensional hydrogel network. The mesh size ξ indicates reentrant behaviour i.e. at first, ξ increases and later decreases as a function of borax concentration. The behaviour is explained on the basis of the balance between the charged di-diol cross-links and the shielding by free ions in the solvent. XRD and DTA show the molecular size of water in the solvent and the glass transition temperature commensurate with reentrant behaviour.

God attachment, mother attachment, and father attachment in early and middle adolescence.

PubMed

Sim, Tick Ngee; Yow, Amanda Shixian

2011-06-01

The present study examined the interplay of attachment to God, attachment to mother, and attachment to father with respect to adjustment (hope, self-esteem, depression) for 130 early and 106 middle adolescents in Singapore. Results showed that the parental attachments were generally linked (in expected directions) to adjustment. God attachment, however, had unique results. At the bivariate level, God attachment was only linked to early adolescents' self-esteem. When considered together with parental attachments (including interactions), God attachment did not emerge as the key moderator in attachment interactions and yielded some unexpected results (e.g., being positively linked to depression). These results are discussed viz-a-viz the secure base and safe haven functions that God and parental attachments may play during adolescence.

Kinetics versus thermodynamics in materials modeling: The case of the di-vacancy in iron

NASA Astrophysics Data System (ADS)

Djurabekova, F.; Malerba, L.; Pasianot, R. C.; Olsson, P.; Nordlund, K.

2010-07-01

Monte Carlo models are widely used for the study of microstructural and microchemical evolution of materials under irradiation. However, they often link explicitly the relevant activation energies to the energy difference between local equilibrium states. We provide a simple example (di-vacancy migration in iron) in which a rigorous activation energy calculation, by means of both empirical interatomic potentials and density functional theory methods, clearly shows that such a link is not granted, revealing a migration mechanism that a thermodynamics-linked activation energy model cannot predict. Such a mechanism is, however, fully consistent with thermodynamics. This example emphasizes the importance of basing Monte Carlo methods on models where the activation energies are rigorously calculated, rather than deduced from widespread heuristic equations.

Impact of turbulent phase noise on frequency transfer with asymmetric two-way ground-satellite coherent optical links

NASA Astrophysics Data System (ADS)

Robert, Clélia; Conan, Jean-Marc; Wolf, Peter

2016-06-01

Bidirectional ground-satellite laser links suffer from turbulence-induced scintillation and phase distortion. We study how turbulence impacts on coherent detection capacity and on the associated phase noise that restricts clock transfer precision. We evaluate the capacity to obtain a two-way cancellation of atmospheric effects despite the asymmetry between up and down link that limits the link reciprocity. For ground-satellite links, the asymmetry is induced by point-ahead angle and possibly the use, for the ground terminal, of different transceiver diameters, in reception and emission. The quantitative analysis is obtained thanks to refined end- to-end simulations under realistic turbulence and wind conditions as well as satellite cinematic. These temporally resolved simulations allow characterizing the coherent detection in terms of time series of heterodyne efficiency for different system parameters. We show that Tip/Tilt correction on ground is mandatory at reception for the down link and as a pre-compensation of the up link. Good correlation between up and down phase noise is obtained even with asymmetric apertures of the ground transceiver and in spite of pointing ahead angle. The reduction to less than 1 rad2 of the two-way differential phase noise is very promising for clock comparisons.

The use of cross-linked chitosan beads for nutrients (nitrate and orthophosphate) removal from a mixture of P-PO4, N-NO2 and N-NO3.

PubMed

Jóźwiak, Tomasz; Filipkowska, Urszula; Szymczyk, Paula; Kuczajowska-Zadrożna, Małgorzata; Mielcarek, Artur

2017-11-01

A hydrogel chitosan sorbent ionically cross-linked with sodium citrate and covalently cross-linked with epichlorohydrin was used to remove nutrients from an equimolar mixture of P-PO 4 , N-NO 2 and N-NO 3 . The scope of the study included, among other things, determination of the influence of pH on nutrient sorption effectiveness, nutrient sorption kinetics as well as determination of the maximum sorption capacity of cross-linked chitosan sorbents regarding P-PO 4 (H 2 PO 4 - , HPO 4 2- ), N-NO 2 (HNO 2 , NO 2 - ), and N-NO 3 (NO 3 - ). The effect of the type of the cross-linking agent on the affinity of the modified chitosan to each nutrient was studied as well. The kinetics of nutrient sorption on the tested chitosan sorbents was best described with the pseudo-second order model. The model of intramolecular diffusion showed that P-PO 4 , N-NO 2 and N-NO3 sorption on cross-linked hydrogel chitosan beads proceeded in two phases. The best sorbent of nutrients turned out to be chitosan cross-linked covalently with epichlorohydrin; with P-PO 4 , N-NO 2 and N-NO 3 sorption capacity reaching: 1.23, 0.94 and 0.76mmol/g, respectively (total of 2.92mmol/g). For comparison, the sorption capacity of chitosan cross-linked ionically with sodium citrate was: 0.43, 0.39 and 0.39mmol/g for P-PO 4 , N-NO 2 and N-NO 3 , respectively (total of 1.21mmol/g). Copyright © 2017 Elsevier B.V. All rights reserved.

A simulator investigation of the use of digital data link for pilot/ATC communications in a single pilot operation

NASA Technical Reports Server (NTRS)

Hinton, David A.; Lohr, Gary W.

1988-01-01

Studies have shown that radio communications between pilots and air traffic control contribute to high pilot workload and are subject to various errors. These errors result from congestion on the voice radio channel, and missed and misunderstood messages. The use of digital data link has been proposed as a means of reducing this workload and error rate. A critical factor, however, in determining the potential benefit of data link will be the interface between future data link systems and the operator of those systems, both in the air and on the ground. The purpose of this effort was to evaluate the pilot interface with various levels of data link capability, in simulated general aviation, single-pilot instrument flight rule operations. Results show that the data link reduced demands on pilots' short-term memory, reduced the number of communication transmissions, and permitted the pilots to more easily allocate time to critical cockpit tasks while receiving air traffic control messages. The pilots who participated unanimously indicated a preference for data link communications over voice-only communications. There were, however, situations in which the pilot preferred the use of voice communications, and the ability for pilots to delay processing the data link messages, during high workload events, caused delays in the acknowledgement of messages to air traffic control.

The social brain: scale-invariant layering of Erdős-Rényi networks in small-scale human societies.

PubMed

Harré, Michael S; Prokopenko, Mikhail

2016-05-01

The cognitive ability to form social links that can bind individuals together into large cooperative groups for safety and resource sharing was a key development in human evolutionary and social history. The 'social brain hypothesis' argues that the size of these social groups is based on a neurologically constrained capacity for maintaining long-term stable relationships. No model to date has been able to combine a specific socio-cognitive mechanism with the discrete scale invariance observed in ethnographic studies. We show that these properties result in nested layers of self-organizing Erdős-Rényi networks formed by each individual's ability to maintain only a small number of social links. Each set of links plays a specific role in the formation of different social groups. The scale invariance in our model is distinct from previous 'scale-free networks' studied using much larger social groups; here, the scale invariance is in the relationship between group sizes, rather than in the link degree distribution. We also compare our model with a dominance-based hierarchy and conclude that humans were probably egalitarian in hunter-gatherer-like societies, maintaining an average maximum of four or five social links connecting all members in a largest social network of around 132 people. © 2016 The Author(s).

Effect of curcumin caged silver nanoparticle on collagen stabilization for biomedical applications.

PubMed

Srivatsan, Kunnavakkam Vinjimur; Duraipandy, N; Begum, Shajitha; Lakra, Rachita; Ramamurthy, Usha; Korrapati, Purna Sai; Kiran, Manikantan Syamala

2015-04-01

The current study aims at understanding the influence of curcumin caged silver nanoparticle (CCSNP) on stability of collagen. The results indicated that curcumin caged silver nanoparticles efficiently stabilize collagen, indicated by enhanced tensile strength, fibril formation and viscosity. The tensile strength of curcumin caged silver nanoparticle cross-linked collagen and elongation at break was also found to be higher than glutaraldehyde cross-linked collagen. The physicochemical characteristics of curcumin caged nanoparticle cross-linked collagen exhibited enhanced strength. The thermal properties were also good with both thermal degradation temperature and hydrothermal stability higher than native collagen. CD analysis showed no structural disparity in spite of superior physicochemical properties suggesting the significance of curcumin caged nanoparticle mediated cross-linking. The additional enhancement in the stabilization of collagen could be attributed to multiple sites for interaction with collagen molecule provided by curcumin caged silver nanoparticles. The results of cell proliferation and anti-microbial activity assays indicated that curcumin caged silver nanoparticles promoted cell proliferation and inhibited microbial growth making it an excellent biomaterial for wound dressing application. The study opens scope for nano-biotechnological strategies for the development of alternate non-toxic cross-linking agents facilitating multiple site interaction thereby improving therapeutic values to the collagen for biomedical application. Copyright © 2015 Elsevier B.V. All rights reserved.

The hydrological calibration and validation of a complexly-linked watershed reservoir model for the Occoquan watershed, Virginia

NASA Astrophysics Data System (ADS)

Xu, Zhongyan; Godrej, Adil N.; Grizzard, Thomas J.

2007-10-01

SummaryRunoff models such as HSPF and reservoir models such as CE-QUAL-W2 are used to model water quality in watersheds. Most often, the models are independently calibrated to observed data. While this approach can achieve good calibration, it does not replicate the physically-linked nature of the system. When models are linked by using the model output from an upstream model as input to a downstream model, the physical reality of a continuous watershed, where the overland and waterbody portions are parts of the whole, is better represented. There are some additional challenges in the calibration of such linked models, because the aim is to simulate the entire system as a whole, rather than piecemeal. When public entities are charged with model development, one of the driving forces is to use public-domain models. This paper describes the use of two such models, HSPF and CE-QUAL-W2, in the linked modeling of the Occoquan watershed located in northern Virginia, USA. The description of the process is provided, and results from the hydrological calibration and validation are shown. The Occoquan model consists of six HSPF and two CE-QUAL-W2 models, linked in a complex way, to simulate two major reservoirs and the associated drainage areas. The overall linked model was calibrated for a three-year period and validated for a two-year period. The results show that a successful calibration can be achieved using the linked approach, with moderate additional effort. Overall flow balances based on the three-year calibration period at four stream stations showed agreement ranging from -3.95% to +3.21%. Flow balances for the two reservoirs, compared via the daily water surface elevations, also showed good agreement ( R2 values of 0.937 for Lake Manassas and 0.926 for Occoquan Reservoir), when missing (un-monitored) flows were included. Validation of the models ranged from poor to fair for the watershed models and excellent for the waterbody models, thus indicating that the current model can be used to explore waterbody issues, but should be used with appropriate care for watershed issues. The study objective of being able to use the Occoquan model to study the impact of land use changes on hydrodynamics and water quality in the waterbodies, particularly the Occoquan Reservoir, can be met with the current model. However, appropriate judgment should be exercised when using the model for the prediction of watershed runoff. One of the advantages of using the linked approach is to develop a direct linkage between upstream land use changes and downstream water quality. This makes it easier for decision-makers to evaluate alternative watershed management plans and for the public to understand the decision-making process. The successful calibration of hydrology provides a solid base for further model development and application.

Oligomerisation of Synaptobrevin-2 Studied by Native Mass Spectrometry and Chemical Cross-Linking

NASA Astrophysics Data System (ADS)

Wittig, Sabine; Haupt, Caroline; Hoffmann, Waldemar; Kostmann, Susann; Pagel, Kevin; Schmidt, Carla

2018-06-01

Synaptobrevin-2 is a key player in signal transmission in neurons. It forms, together with SNAP25 and Syntaxin-1A, the neuronal soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex and mediates exocytosis of synaptic vesicles with the pre-synaptic membrane. While Synaptobrevin-2 is part of a four-helix bundle in this SNARE complex, it is natively unstructured in the absence of lipids or other SNARE proteins. Partially folded segments, presumably SNARE complex formation intermediates, as well as formation of Synaptobrevin-2 dimers and oligomers, were identified in previous studies. Here, we employ three Synaptobrevin-2 variants—the full-length protein Syb(1-116), the soluble, cytosolic variant Syb(1-96) as well as a shorter version Syb(49-96) containing structured segments but omitting a trigger site for SNARE complex formation—to study oligomerisation in the absence of interaction partners or when incorporated into the lipid bilayer of liposomes. Combining native mass spectrometry with chemical cross-linking, we find that the truncated versions show increased oligomerisation. Our findings from both techniques agree well and confirm the presence of oligomers in solution while membrane-bound Synaptobrevin-2 is mostly monomeric. Using ion mobility mass spectrometry, we could further show that lower charge states of Syb(49-96) oligomers, which most likely represent solution structures, follow an isotropic growth curve suggesting that they are intrinsically disordered. From a technical point of view, we show that the combination of native ion mobility mass spectrometry with chemical cross-linking is well-suited for the analysis of protein homo-oligomers. [Figure not available: see fulltext.

Silk fibroin-Thelebolan matrix: A promising chemopreventive scaffold for soft tissue cancer.

PubMed

Mukhopadhyay, Sourav K; Naskar, Deboki; Bhattacharjee, Promita; Mishra, Abheepsa; Kundu, Subhas C; Dey, Satyahari

2017-07-01

Research of improved functional bio-mimetic matrix for regenerative medicine is currently one of the rapidly growing fields in tissue engineering and medical sciences. This study reports a novel bio-polymeric matrix, which is fabricated using silk protein fibroin from Bombyx mori silkworm and fungal exopolysaccharide Thelebolan from Antarctic fungus Thelebolus sp. IITKGP-BT12 by solvent evaporation and freeze drying method. Natural cross linker genipin is used to imprison the Thelebolan within the fibroin network. Different cross-linked and non-cross-linked fibroin/Thelebolan matrices are fabricated and biophysically characterized. Cross-linked thin films show robustness, good mechanical strength and high temperature stability in comparison to non-cross-linked and pure matrices. The 3D sponge matrices demonstrate good cytocompatibility. Interestingly, sustained release of the Thelebolan from the cross-linked matrices induce apoptosis in colon cancer cell line (HT-29) in time dependent manner while it is nontoxic to the normal fibroblast cells (L929).The findings indicate that the cross-linked fibroin/Thelebolan matrices can be used as potential topical chemopreventive scaffold for preclusion of soft tissue carcinoma. Copyright © 2017 Elsevier B.V. All rights reserved.

A new mutually reinforcing network node and link ranking algorithm

PubMed Central

Wang, Zhenghua; Dueñas-Osorio, Leonardo; Padgett, Jamie E.

2015-01-01

This study proposes a novel Normalized Wide network Ranking algorithm (NWRank) that has the advantage of ranking nodes and links of a network simultaneously. This algorithm combines the mutual reinforcement feature of Hypertext Induced Topic Selection (HITS) and the weight normalization feature of PageRank. Relative weights are assigned to links based on the degree of the adjacent neighbors and the Betweenness Centrality instead of assigning the same weight to every link as assumed in PageRank. Numerical experiment results show that NWRank performs consistently better than HITS, PageRank, eigenvector centrality, and edge betweenness from the perspective of network connectivity and approximate network flow, which is also supported by comparisons with the expensive N-1 benchmark removal criteria based on network efficiency. Furthermore, it can avoid some problems, such as the Tightly Knit Community effect, which exists in HITS. NWRank provides a new inexpensive way to rank nodes and links of a network, which has practical applications, particularly to prioritize resource allocation for upgrade of hierarchical and distributed networks, as well as to support decision making in the design of networks, where node and link importance depend on a balance of local and global integrity. PMID:26492958

Node, Node-Link, and Node-Link-Group Diagrams: An Evaluation.

PubMed

Saket, Bahador; Simonetto, Paolo; Kobourov, Stephen; Börner, Katy

2014-12-01

Effectively showing the relationships between objects in a dataset is one of the main tasks in information visualization. Typically there is a well-defined notion of distance between pairs of objects, and traditional approaches such as principal component analysis or multi-dimensional scaling are used to place the objects as points in 2D space, so that similar objects are close to each other. In another typical setting, the dataset is visualized as a network graph, where related nodes are connected by links. More recently, datasets are also visualized as maps, where in addition to nodes and links, there is an explicit representation of groups and clusters. We consider these three Techniques, characterized by a progressive increase of the amount of encoded information: node diagrams, node-link diagrams and node-link-group diagrams. We assess these three types of diagrams with a controlled experiment that covers nine different tasks falling broadly in three categories: node-based tasks, network-based tasks and group-based tasks. Our findings indicate that adding links, or links and group representations, does not negatively impact performance (time and accuracy) of node-based tasks. Similarly, adding group representations does not negatively impact the performance of network-based tasks. Node-link-group diagrams outperform the others on group-based tasks. These conclusions contradict results in other studies, in similar but subtly different settings. Taken together, however, such results can have significant implications for the design of standard and domain snecific visualizations tools.

A shared neural ensemble links distinct contextual memories encoded close in time

NASA Astrophysics Data System (ADS)

Cai, Denise J.; Aharoni, Daniel; Shuman, Tristan; Shobe, Justin; Biane, Jeremy; Song, Weilin; Wei, Brandon; Veshkini, Michael; La-Vu, Mimi; Lou, Jerry; Flores, Sergio E.; Kim, Isaac; Sano, Yoshitake; Zhou, Miou; Baumgaertel, Karsten; Lavi, Ayal; Kamata, Masakazu; Tuszynski, Mark; Mayford, Mark; Golshani, Peyman; Silva, Alcino J.

2016-06-01

Recent studies suggest that a shared neural ensemble may link distinct memories encoded close in time. According to the memory allocation hypothesis, learning triggers a temporary increase in neuronal excitability that biases the representation of a subsequent memory to the neuronal ensemble encoding the first memory, such that recall of one memory increases the likelihood of recalling the other memory. Here we show in mice that the overlap between the hippocampal CA1 ensembles activated by two distinct contexts acquired within a day is higher than when they are separated by a week. Several findings indicate that this overlap of neuronal ensembles links two contextual memories. First, fear paired with one context is transferred to a neutral context when the two contexts are acquired within a day but not across a week. Second, the first memory strengthens the second memory within a day but not across a week. Older mice, known to have lower CA1 excitability, do not show the overlap between ensembles, the transfer of fear between contexts, or the strengthening of the second memory. Finally, in aged mice, increasing cellular excitability and activating a common ensemble of CA1 neurons during two distinct context exposures rescued the deficit in linking memories. Taken together, these findings demonstrate that contextual memories encoded close in time are linked by directing storage into overlapping ensembles. Alteration of these processes by ageing could affect the temporal structure of memories, thus impairing efficient recall of related information.

Familial ethnic socialization, gender role attitudes, and ethnic identity development in Mexican-origin early adolescents.

PubMed

Sanchez, Delida; Whittaker, Tiffany A; Hamilton, Emma; Arango, Sarah

2017-07-01

This study examined the relations between familial ethnic socialization and ethnic identity development in 438 Mexican-origin (n = 242 boys and n = 196 girls) preadolescents. In addition, machismo and marianismo gender role attitudes were examined as potential mediators in this link. Confirmatory factor analyses (CFA) of the Familial Ethnic Socialization Scale (FES), Machismo Measure (MM), Marianismo Beliefs Scale (MBS), and the Ethnic Identity Brief Scale (EISB) were conducted to test the factor structure with a preadolescent Mexican-origin sample. Separate path analyses of analytic models were then performed on boys and girls. Results of the CFAs for survey measures revealed that for the FES, a 1-factor version indicated acceptable fit; for the MM, the original 2-factor structure indicated acceptable model fit; for the MBS, a revised 3-factor version indicated acceptable model fit; and, for the EISB, the affirmation and resolution dimensions showed acceptable fit. Among boys, FES was significantly and positively linked to caballerismo, and EISB affirmation and resolution; furthermore, the links between FES and EISB affirmation and resolution were indirectly connected by caballerismo. In addition, traditional machismo was negatively linked to EISB affirmation, and caballerismo was positively linked to EISB affirmation and resolution. Among girls, FES was significantly and positively related to the MBS-virtuous/chaste pillar, and EISB affirmation and resolution. The MBS-subordinate to others pillar was negatively linked to EISB affirmation. This study underscores the importance of FES and positive gender role attitudes in the link to ethnic identity development among Mexican-origin preadolescents. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Sex-dependent selection differentially shapes genetic variation on and off the guppy Y chromosome.

PubMed

Postma, Erik; Spyrou, Nicolle; Rollins, Lee Ann; Brooks, Robert C

2011-08-01

Because selection is often sex-dependent, alleles can have positive effects on fitness in one sex and negative effects in the other, resulting in intralocus sexual conflict. Evolutionary theory predicts that intralocus sexual conflict can drive the evolution of sex limitation, sex-linkage, and sex chromosome differentiation. However, evidence that sex-dependent selection results in sex-linkage is limited. Here, we formally partition the contribution of Y-linked and non-Y-linked quantitative genetic variation in coloration, tail, and body size of male guppies (Poecilia reticulata)-traits previously implicated as sexually antagonistic. We show that these traits are strongly genetically correlated, both on and off the Y chromosome, but that these correlations differ in sign and magnitude between both parts of the genome. As predicted, variation in attractiveness was found to be associated with the Y-linked, rather than with the non-Y-linked component of genetic variation in male ornamentation. These findings show how the evolution of Y-linkage may be able to resolve sexual conflict. More generally, they provide unique insight into how sex-specific selection has the potential to differentially shape the genetic architecture of fitness traits across different parts of the genome. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Technology and Thematic Units: A Primary Example (Technology Links to Literacy).

ERIC Educational Resources Information Center

Wepner, Shelley B.

1992-01-01

Uses a teacher's thematic unit on endangered species to share how technology can help to make meaningful connections across the curriculum. Shows how the unit includes science, social studies, mathematics, art, language arts, and music. (SR)

Nutrition and Learning.

ERIC Educational Resources Information Center

Black, Susan

2000-01-01

Studies by Tufts University's Center on Hunger and Poverty show conclusive links between nutrition and children's cognitive development. Cognitive defects can result from complex interactions between malnutrition and "environmental insults" that come from living in poverty. Poor nutrition has longterm consequences. Print and web…

Influence of cross-link structure, density and mechanical properties in the mesoscale deformation mechanisms of collagen fibrils

PubMed Central

Depalle, Baptiste; Qin, Zhao; Shefelbine, Sandra J.; Buehler, Markus J.

2015-01-01

Collagen is a ubiquitous protein with remarkable mechanical properties. It is highly elastic, shows large fracture strength and enables substantial energy dissipation during deformation. Most of the connective tissue in humans consists of collagen fibrils composed of a staggered array of tropocollagen molecules, which are connected by intermolecular cross-links. In this study, we report a three-dimensional coarse-grained model of collagen and analyze the influence of enzymatic cross-links on the mechanics of collagen fibrils. Two representatives immature and mature cross-links are implemented in the mesoscale model using a bottom-up approach. By varying the number, type and mechanical properties of cross-links in the fibrils and performing tensile test on the models, we systematically investigate the deformation mechanisms of cross-linked collagen fibrils. We find that cross-linked fibrils exhibit a three phase behavior, which agrees closer with experimental results than what was obtained using previous models. The fibril mechanical response is characterized by: (i) an initial elastic deformation corresponding to the collagen molecule uncoiling, (ii) a linear regime dominated by molecule sliding and (iii) the second stiffer elastic regime related to the stretching of the backbone of the tropocollagen molecules until the fibril ruptures. Our results suggest that both cross-link density and type dictate the stiffness of large deformation regime by increasing the number of interconnected molecules while cross-links mechanical properties determine the failure strain and strength of the fibril. These findings reveal that cross-links play an essential role in creating an interconnected fibrillar material of tunable toughness and strength. PMID:25153614

Self-assembling cyclic tetrapeptide from alternating C-linked carbo-beta-amino acid [(S)-beta-Caa] and alpha-aminoxy acid [(R)-Ama]: a selective chloride ion receptor.

PubMed

Sharma, Gangavaram V M; Manohar, Vennampalli; Dutta, Samit Kumar; Sridhar, Bojja; Ramesh, Venna; Srinivas, Ragampeta; Kunwar, Ajit C

2010-02-19

A cyclic tetrapeptide is prepared from alternating (S)-beta-Caa (C-linked carbo-beta-amino acid) and (R)-Ama (alpha-aminoxy acid). Extensive NMR (in CDCl(3) solution) and mass spectral (MS) studies show its halide binding capacity, with a special affinity to the chloride ion. At higher concentration it was found to form molecular aggregates as evidenced from transmission electron microscopic and atomic force microscopic analysis, confirming the formation of nanorods.

Epinigericin toxicity towards Tetrahymena pyriformis GL; changes in cell volume and intracellular pH.

PubMed

Bamdad, M; David, L; Grolière, C A

1995-12-01

A study of the toxicity of epinigericin, an antibiotic ionophor, towards the ciliate Tetrahymena pyriformis showed that this molecule stopped cell division, increased cell volume and led to a more basic intracellular pH. The action of epinigericin was probably linked to its function as an ionophor. The ionic selectivity of this molecule is still not known. The raising of the intracellular pH of ciliates by this antibiotic may be linked to its toxic action and its iontransport mechanism in Tetrahymena.

Two genetic markers closely linked to adult polycystic kidney disease on chromosome 16.

PubMed Central

Reeders, S T; Breuning, M H; Corney, G; Jeremiah, S J; Meera Khan, P; Davies, K E; Hopkinson, D A; Pearson, P L; Weatherall, D J

1986-01-01

The genetic locus for autosomal dominant adult polycystic kidney disease was recently assigned to chromosome 16 by the finding of genetic linkage to the alpha globin gene cluster. Further study showed that the phosphoglycolate phosphatase locus is also closely linked to both the locus for adult polycystic kidney disease and the alpha globin gene cluster. These findings have important implications for the prenatal and presymptomatic diagnosis of adult polycystic kidney disease and for a better understanding of its pathogenesis. Images FIG 1 PMID:3008903

Effect of atmospheric anisoplanatism on earth-to-satellite time transfer over laser communication links.

PubMed

Belmonte, Aniceto; Taylor, Michael T; Hollberg, Leo; Kahn, Joseph M

2017-07-10

The need for an accurate time reference on orbiting platforms motivates study of time transfer via free-space optical communication links. The impact of atmospheric turbulence on earth-to-satellite optical time transfer has not been fully characterized, however. We analyze limits to two-way laser time transfer accuracy posed by anisoplanatic non-reciprocity between uplink and downlink. We show that despite limited reciprocity, two-way time transfer can still achieve sub-picosecond accuracy in realistic propagation scenarios over a single satellite visibility period.

Network clustering and community detection using modulus of families of loops.

PubMed

Shakeri, Heman; Poggi-Corradini, Pietro; Albin, Nathan; Scoglio, Caterina

2017-01-01

We study the structure of loops in networks using the notion of modulus of loop families. We introduce an alternate measure of network clustering by quantifying the richness of families of (simple) loops. Modulus tries to minimize the expected overlap among loops by spreading the expected link usage optimally. We propose weighting networks using these expected link usages to improve classical community detection algorithms. We show that the proposed method enhances the performance of certain algorithms, such as spectral partitioning and modularity maximization heuristics, on standard benchmarks.

Design and Synthesis of Novel Arylketo-containing P1-P3 Linked Macro-cyclic BACE-1 Inhibitors

PubMed Central

Sandgren, Veronica; Belda, Oscar; Kvarnström, Ingemar; Lindberg, Jimmy; Samuelsson, Bertil; Dahlgren, Anders

2015-01-01

A series of arylketo-containing P1-P3 linked macrocyclic BACE-1 inhibitors were designed, synthesized, and compared with compounds with a previously known and extensively studied corresponding P2 isophthalamide moiety with the aim to improve on permeability whilst retaining the enzyme- and cell-based activities. Several inhibitors displayed substantial increases in Caco-2 cell-based permeability compared to earlier synthesized inhibitors and notably also with retained activities, showing that this approach might yield BACE-1 inhibitors with improved properties. PMID:25937848

Design and optimization of a fiber optic data link for new generation on-board SAR processing architectures

NASA Astrophysics Data System (ADS)

Ciminelli, Caterina; Dell'Olio, Francesco; Armenise, Mario N.; Iacomacci, Francesco; Pasquali, Franca; Formaro, Roberto

2017-11-01

A fiber optic digital link for on-board data handling is modeled, designed and optimized in this paper. Design requirements and constraints relevant to the link, which is in the frame of novel on-board processing architectures, are discussed. Two possible link configurations are investigated, showing their advantages and disadvantages. An accurate mathematical model of each link component and the entire system is reported and results of link simulation based on those models are presented. Finally, some details on the optimized design are provided.

UV laser-induced cross-linking in peptides

PubMed Central

Leo, Gabriella; Altucci, Carlo; Bourgoin-Voillard, Sandrine; Gravagnuolo, Alfredo M.; Esposito, Rosario; Marino, Gennaro; Costello, Catherine E.; Velotta, Raffaele; Birolo, Leila

2013-01-01

RATIONALE The aim of this study was to demonstrate, and to characterize by high resolution mass spectrometry, that it is possible to preferentially induce covalent cross-links in peptides by using high energy femtosecond UV laser pulses. The cross-link is readily formed only when aromatic amino acids are present in the peptide sequence. METHODS Three peptides, xenopsin, angiotensin I, interleukin, individually or in combination, were exposed to high energy femtosecond UV laser pulses, either alone or in the presence of spin trapping molecules, the reaction products being characterized by high resolution mass spectrometry. RESULTS High resolution mass spectrometry and spin trapping strategies showed that cross-linking occurs readily, proceeds via a radical mechanism, and is the highly dominant reaction, proceeding without causing significant photo-damage in the investigated range of experimental parameters. CONCLUSIONS High energy femtosecond UV laser pulses can be used to induce covalent cross-links between aromatic amino acids in peptides, overcoming photo-oxidation processes, that predominate as the mean laser pulse intensity approaches illumination conditions achievable with conventional UV light sources. PMID:23754800

Link prediction in multiplex online social networks

NASA Astrophysics Data System (ADS)

Jalili, Mahdi; Orouskhani, Yasin; Asgari, Milad; Alipourfard, Nazanin; Perc, Matjaž

2017-02-01

Online social networks play a major role in modern societies, and they have shaped the way social relationships evolve. Link prediction in social networks has many potential applications such as recommending new items to users, friendship suggestion and discovering spurious connections. Many real social networks evolve the connections in multiple layers (e.g. multiple social networking platforms). In this article, we study the link prediction problem in multiplex networks. As an example, we consider a multiplex network of Twitter (as a microblogging service) and Foursquare (as a location-based social network). We consider social networks of the same users in these two platforms and develop a meta-path-based algorithm for predicting the links. The connectivity information of the two layers is used to predict the links in Foursquare network. Three classical classifiers (naive Bayes, support vector machines (SVM) and K-nearest neighbour) are used for the classification task. Although the networks are not highly correlated in the layers, our experiments show that including the cross-layer information significantly improves the prediction performance. The SVM classifier results in the best performance with an average accuracy of 89%.

Link prediction in multiplex online social networks.

PubMed

Jalili, Mahdi; Orouskhani, Yasin; Asgari, Milad; Alipourfard, Nazanin; Perc, Matjaž

2017-02-01

Online social networks play a major role in modern societies, and they have shaped the way social relationships evolve. Link prediction in social networks has many potential applications such as recommending new items to users, friendship suggestion and discovering spurious connections. Many real social networks evolve the connections in multiple layers (e.g. multiple social networking platforms). In this article, we study the link prediction problem in multiplex networks. As an example, we consider a multiplex network of Twitter (as a microblogging service) and Foursquare (as a location-based social network). We consider social networks of the same users in these two platforms and develop a meta-path-based algorithm for predicting the links. The connectivity information of the two layers is used to predict the links in Foursquare network. Three classical classifiers (naive Bayes, support vector machines (SVM) and K-nearest neighbour) are used for the classification task. Although the networks are not highly correlated in the layers, our experiments show that including the cross-layer information significantly improves the prediction performance. The SVM classifier results in the best performance with an average accuracy of 89%.

Cross-linked enzyme aggregates of phenylalanine ammonia lyase: novel biocatalysts for synthesis of L-phenylalanine.

PubMed

Cui, Jian-Dong; Zhang, Si; Sun, Li-Mei

2012-06-01

Cross-linked enzyme aggregates of phenylalanine ammonia lyase (PAL-CLEAs) from Rhodotorula glutinis were prepared. The effects of the type of aggregating agent, its concentration, and that of cross-linking agent were studied. PAL-CLEAs production was most effective using ammonium sulfate (40 % saturation), followed by cross-linking for 1 h with 0.2 % (v/v) glutaraldehyde. Moreover, the storage and operational stability of the resulting PAL-CLEAs were also investigated. Compared to the free enzyme, the PAL-CLEAs exhibited the expected increased stability of the enzyme against various deactivating conditions such as pH, temperature, denaturants, and organic solvents and showed higher storage stability than its soluble counterpart. Additionally, the reusability of PAL-CLEAs with respect to the biotransformation of L-phenylalanine was evaluated. PAL-CLEAs could be recycled at least for 12 consecutive batch reactions without dramatic activity loss, which should dramatically increase the commercial potential of PAL for synthesis of L: -phenylalanine. To the best of our knowledge, this is the first report of immobilization of PAL as cross-linked enzyme aggregates.

Neural correlates of task switching in paternal 15q11-q13 deletion Prader-Willi syndrome.

PubMed

Woodcock, Kate A; Humphreys, Glyn W; Oliver, Chris; Hansen, Peter C

2010-12-02

We report a first study of brain activity linked to task switching in individuals with Prader-Willi syndrome (PWS). PWS individuals show a specific cognitive deficit in task switching which may be associated with the display of temper outbursts and repetitive questioning. The performance of participants with PWS and typically developing controls was matched in a cued task switching procedure, and brain activity was contrasted on switching and non-switching blocks using fMRI. Individuals with PWS did not show the typical frontal-parietal pattern of neural activity associated with switching blocks, with significantly reduced activation in regions of the posterior parietal and ventromedial prefrontal cortices. We suggest that this is linked to a difficulty in PWS in setting appropriate attentional weights to enable task-set reconfiguration. In addition to this, PWS individuals did not show the typical pattern of deactivation, with significantly less deactivation in an anterior region of the ventromedial prefrontal cortex. One plausible explanation for this is that individuals with PWS show dysfunction within the default mode network, which has been linked to attentional control. The data point to functional changes in the neural circuitry supporting task switching in PWS even when behavioural performance is matched to controls and thus highlight neural mechanisms that may be involved in a specific pathway between genes, cognition and behaviour. Copyright © 2010 Elsevier B.V. All rights reserved.

Physicochemical and digestibility properties of double-modified banana ( Musa paradisiaca L.) starches.

PubMed

Carlos-Amaya, Fandila; Osorio-Diaz, Perla; Agama-Acevedo, Edith; Yee-Madeira, Hernani; Bello-Pérez, Luis Arturo

2011-02-23

Banana starch was chemically modified using single (esterification or cross-linking) and dual modification (esterification-cross-linking and cross-linking-esterification), with the objective to increase the slowly digestible starch (SDS) and resistant starch (RS) concentrations. Physicochemical properties and in vitro digestibility were analyzed. The degree of substitution of the esterified samples ranged from 0.006 to 0.020. The X-ray diffraction pattern of the modified samples did not show change; however, an increase in crystallinity level was determined (from 23.79 to 32.76%). The ungelatinized samples had low rapidly digestible starch (RDS) (4.23-9.19%), whereas the modified starches showed an increase in SDS (from 10.79 to 16.79%) and had high RS content (74.07-85.07%). In the cooked samples, the esterified starch increased the SDS content (21.32%), followed by cross-linked starch (15.13%). Dual modified starch (cross-linked-esterified) had the lowest SDS content, but the highest RS amount. The esterified and cross-linked-esterified samples had higher peak viscosity than cross-linked and esterified-cross-linked. This characteristic is due to the fact that in dual modification, the groups introduced in the first modification are replaced by the functional group of the second modification. Temperature and enthalpy of gelatinization decreased in modified starches (from 75.37 to 74.02 °C and from 10.42 to 8.68 J/g, respectively), compared with their unmodified starch (76.15 °C and 11.05 J/g). Cross-linked-esterified starch showed the lowest enthalpy of gelatinization (8.68 J/g). Retrogradation temperature decreased in modified starches compared with unmodified (59.04-57.47 °C), but no significant differences were found among the modified samples.

Soil factors effects on life history attributes of Leiothrix spiralis and Leiothrix vivipara (Eriocaulaceae) on rupestrian grasslands in Southeastern Brazil.

PubMed

Coelho, F F; Martins, R P; Figueira, J E C; Demetrio, G R

2014-11-01

In this study, we hypothesized that the life history traits of Leiothrix spiralis and L. vivipara would be linked to soil factors of the rupestrian grasslands and that rosette size would be influenced by soil moisture. Soil analyses were performed from five populations of L. spiralis and four populations of L. vivipara. In each area, three replicates were employed in 19 areas of occurrence of Leiothrix species, and we quantified the life history attributes. The microhabitats of these species show low favorability regarding to soil factors. During the dry season, their rosettes decreased in diameter due the loss of its most outlying leaves. The absence of seedlings indicated the low fecundity of both species. However, both species showed rapid population growth by pseudovivipary. Both L. spiralis and L. vivipara exhibit a kind of parental care that was quantified by the presence of connections between parental-rosettes and ramets. The findings of the present study show that the life history traits are linked to soil factors.

Land-mobile satellite excess path loss measurements

NASA Astrophysics Data System (ADS)

Hess, G. C.

1980-05-01

An experiment conducted with the ATS-6 satellite to determine the additional path loss over free-space loss experienced by land-mobile communication links is described. This excess path loss is measured as a function of 1) local environment, 2) vehicle heading, 3) link frequency, 4) satellite elevation angle, and 5) street side. A statistical description of excess loss developed from the data shows that the first two parameters dominate. Excess path loss on the order of 25 dB is typical in urban situations, but decreases to under 10 dB in suburban/rural areas. Spaced antenna selection diversity is found to provide only a slight decrease (4 dB, typically) in the urban excess path loss observed. Level crossing rates are depressed in satellite links relative to those of Rayleigh-faded terrestrial links, but increases in average fade durations tend to offset that advantage. The measurements show that the excess path loss difference between 860-MHz links and 1550-MHz links is generally negligible.

Optimal Link Removal for Epidemic Mitigation: A Two-Way Partitioning Approach

PubMed Central

Enns, Eva A.; Mounzer, Jeffrey J.; Brandeau, Margaret L.

2011-01-01

The structure of the contact network through which a disease spreads may influence the optimal use of resources for epidemic control. In this work, we explore how to minimize the spread of infection via quarantining with limited resources. In particular, we examine which links should be removed from the contact network, given a constraint on the number of removable links, such that the number of nodes which are no longer at risk for infection is maximized. We show how this problem can be posed as a non-convex quadratically constrained quadratic program (QCQP), and we use this formulation to derive a link removal algorithm. The performance of our QCQP-based algorithm is validated on small Erdős-Renyi and small-world random graphs, and then tested on larger, more realistic networks, including a real-world network of injection drug use. We show that our approach achieves near optimal performance and out-perform so ther intuitive link removal algorithms, such as removing links in order of edge centrality. PMID:22115862

Health-Related Effects of Creative and Expressive Writing

ERIC Educational Resources Information Center

Lowe, Geoff

2006-01-01

Purpose: The purpose of this paper is to provide an overview of some health-related effects of creative and expressive writing. Design/methodology/approach: Reviews some of the main research studies exploring links between expressive writing and aspects of health, including two new experimental studies showing effects of poetry on mood and immune…

Comparing Fathers' Physical and Toy Play and Links to Child Behaviour: An Exploratory Study

ERIC Educational Resources Information Center

St George, Jennifer; Fletcher, Richard; Palazzi, Kerrin

2017-01-01

Increasing amounts of research show that fathers' involvement in children's lives contributes to the child's social, emotional and cognitive development; however, much of the evidence comes from fathers' caregiving and object play. This exploratory study compared the characteristics of 24 Australian fathers' play in two contexts--toy play and…

"Ser" and "Estar": Corrective Input to Children's Errors of the Spanish Copula Verbs

ERIC Educational Resources Information Center

Holtheuer, Carolina; Rendle-Short, Johanna

2013-01-01

Evidence for the role of corrective input as a facilitator of language acquisition is inconclusive. Studies show links between corrective input and grammatical use of some, but not other, language structures. The present study examined relationships between corrective parental input and children's errors in the acquisition of the Spanish copula…

Choosing to Compromise: Women Studying Childcare

ERIC Educational Resources Information Center

Wright, Hazel R.

2013-01-01

Reporting on a study of mature women training to work in childcare, this article demonstrates how some women choose to be part-time mothers, workers and students, wanting "the best of both worlds". It presents a theory of integrated lives that contrasts with customary deficit models and shows how a series of reciprocal links bind the…

Vasopressin Proves Es-sense-tial: Vasopressin and the Modulation of Sensory Processing in Mammals

PubMed Central

Bester-Meredith, Janet K.; Fancher, Alexandria P.; Mammarella, Grace E.

2015-01-01

As mammals develop, they encounter increasing social complexity in the surrounding world. In order to survive, mammals must show appropriate behaviors toward their mates, offspring, and same-sex conspecifics. Although the behavioral effects of the neuropeptide arginine vasopressin (AVP) have been studied in a variety of social contexts, the effects of this neuropeptide on multimodal sensory processing have received less attention. AVP is widely distributed through sensory regions of the brain and has been demonstrated to modulate olfactory, auditory, gustatory, and visual processing. Here, we review the evidence linking AVP to the processing of social stimuli in sensory regions of the brain and explore how sensory processing can shape behavioral responses to these stimuli. In addition, we address the interplay between hormonal and neural AVP in regulating sensory processing of social cues. Because AVP pathways show plasticity during development, early life experiences may shape life-long processing of sensory information. Furthermore, disorders of social behavior such as autism and schizophrenia that have been linked with AVP also have been linked with dysfunctions in sensory processing. Together, these studies suggest that AVP’s diversity of effects on social behavior across a variety of mammalian species may result from the effects of this neuropeptide on sensory processing. PMID:25705203

Design, synthesis and DNA-binding study of some novel morpholine linked thiazolidinone derivatives

NASA Astrophysics Data System (ADS)

War, Javeed Ahmad; Srivastava, Santosh Kumar; Srivastava, Savitri Devi

2017-02-01

The emergence of multiple drug resistance amongst bacterial strains resulted in many clinical drugs to be ineffective. Being vulnerable to bacterial infections any lack in the development of new antimicrobial drugs could pose a serious threat to public health. Here we report design and synthesis of a novel class of morpholine linked thiazolidinone hybrid molecules. The compounds were characterized by FT-IR, NMR and HRMS techniques. Susceptibility tests showed that most of the synthesized molecules were highly active against multiple bacterial strains. Compound 3f displayed MIC values which were better than the standard drug for most of the tested strains. DNA being a well defined target for many antimicrobial drugs was probed as possible target for these synthetic molecules. DNA-binding study of 3f with sm-DNA was probed through UV-vis absorption, fluorescence quenching, gel electrophoresis and molecular docking techniques. The studies revealed that compound 3f has strong affinity towards DNA and binds at the minor groove. The docking studies revealed that the compound 3f shows preferential binding towards A/T residues.

Design, synthesis and DNA-binding study of some novel morpholine linked thiazolidinone derivatives.

PubMed

War, Javeed Ahmad; Srivastava, Santosh Kumar; Srivastava, Savitri Devi

2017-02-15

The emergence of multiple drug resistance amongst bacterial strains resulted in many clinical drugs to be ineffective. Being vulnerable to bacterial infections any lack in the development of new antimicrobial drugs could pose a serious threat to public health. Here we report design and synthesis of a novel class of morpholine linked thiazolidinone hybrid molecules. The compounds were characterized by FT-IR, NMR and HRMS techniques. Susceptibility tests showed that most of the synthesized molecules were highly active against multiple bacterial strains. Compound 3f displayed MIC values which were better than the standard drug for most of the tested strains. DNA being a well defined target for many antimicrobial drugs was probed as possible target for these synthetic molecules. DNA-binding study of 3f with sm-DNA was probed through UV-vis absorption, fluorescence quenching, gel electrophoresis and molecular docking techniques. The studies revealed that compound 3f has strong affinity towards DNA and binds at the minor groove. The docking studies revealed that the compound 3f shows preferential binding towards A/T residues. Copyright © 2016 Elsevier B.V. All rights reserved.

Impact of the global economic crisis on metal levels in particulate matter (PM) at an urban area in the Cantabria Region (Northern Spain).

PubMed

Arruti, A; Fernández-Olmo, I; Irabien, A

2011-05-01

Air pollution by particulate matter is well linked with anthropogenic activities; the global economic crisis that broke out in the last year may be a proper indicator of this close relationship. Some economic indicators show the regional effects of the crisis on the Cantabria Region. The present work aims to evaluate the impact of the economic crisis on PM10 levels and composition at the major city of the region, Santander. Some metals linked to anthropogenic activities were measured at Santander and studied by Positive Matrix Factorization; this statistical analysis allowed to identify three main factors: urban background, industrial and molybdenum-related factor. The main results show that the temporal trend of the levels of the industrial tracers found in the present study are well agree with the evolution of the studied economic indicators; nevertheless, the urban background tracers and PM10 concentration levels are not well correlated with the studied economic indicators. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cyclophilin-B Modulates Collagen Cross-linking by Differentially Affecting Lysine Hydroxylation in the Helical and Telopeptidyl Domains of Tendon Type I Collagen*

PubMed Central

Terajima, Masahiko; Taga, Yuki; Chen, Yulong; Cabral, Wayne A.; Hou-Fu, Guo; Srisawasdi, Sirivimol; Nagasawa, Masako; Sumida, Noriko; Hattori, Shunji; Kurie, Jonathan M.; Marini, Joan C.; Yamauchi, Mitsuo

2016-01-01

Covalent intermolecular cross-linking provides collagen fibrils with stability. The cross-linking chemistry is tissue-specific and determined primarily by the state of lysine hydroxylation at specific sites. A recent study on cyclophilin B (CypB) null mice, a model of recessive osteogenesis imperfecta, demonstrated that lysine hydroxylation at the helical cross-linking site of bone type I collagen was diminished in these animals (Cabral, W. A., Perdivara, I., Weis, M., Terajima, M., Blissett, A. R., Chang, W., Perosky, J. E., Makareeva, E. N., Mertz, E. L., Leikin, S., Tomer, K. B., Kozloff, K. M., Eyre, D. R., Yamauchi, M., and Marini, J. C. (2014) PLoS Genet. 10, e1004465). However, the extent of decrease appears to be tissue- and molecular site-specific, the mechanism of which is unknown. Here we report that although CypB deficiency resulted in lower lysine hydroxylation in the helical cross-linking sites, it was increased in the telopeptide cross-linking sites in tendon type I collagen. This resulted in a decrease in the lysine aldehyde-derived cross-links but generation of hydroxylysine aldehyde-derived cross-links. The latter were absent from the wild type and heterozygous mice. Glycosylation of hydroxylysine residues was moderately increased in the CypB null tendon. We found that CypB interacted with all lysyl hydroxylase isoforms (isoforms 1–3) and a putative lysyl hydroxylase-2 chaperone, 65-kDa FK506-binding protein. Tendon collagen in CypB null mice showed severe size and organizational abnormalities. The data indicate that CypB modulates collagen cross-linking by differentially affecting lysine hydroxylation in a site-specific manner, possibly via its interaction with lysyl hydroxylases and associated molecules. This study underscores the critical importance of collagen post-translational modifications in connective tissue formation. PMID:26934917

Cyclophilin-B Modulates Collagen Cross-linking by Differentially Affecting Lysine Hydroxylation in the Helical and Telopeptidyl Domains of Tendon Type I Collagen.

PubMed

Terajima, Masahiko; Taga, Yuki; Chen, Yulong; Cabral, Wayne A; Hou-Fu, Guo; Srisawasdi, Sirivimol; Nagasawa, Masako; Sumida, Noriko; Hattori, Shunji; Kurie, Jonathan M; Marini, Joan C; Yamauchi, Mitsuo

2016-04-29

Covalent intermolecular cross-linking provides collagen fibrils with stability. The cross-linking chemistry is tissue-specific and determined primarily by the state of lysine hydroxylation at specific sites. A recent study on cyclophilin B (CypB) null mice, a model of recessive osteogenesis imperfecta, demonstrated that lysine hydroxylation at the helical cross-linking site of bone type I collagen was diminished in these animals (Cabral, W. A., Perdivara, I., Weis, M., Terajima, M., Blissett, A. R., Chang, W., Perosky, J. E., Makareeva, E. N., Mertz, E. L., Leikin, S., Tomer, K. B., Kozloff, K. M., Eyre, D. R., Yamauchi, M., and Marini, J. C. (2014) PLoS Genet 10, e1004465). However, the extent of decrease appears to be tissue- and molecular site-specific, the mechanism of which is unknown. Here we report that although CypB deficiency resulted in lower lysine hydroxylation in the helical cross-linking sites, it was increased in the telopeptide cross-linking sites in tendon type I collagen. This resulted in a decrease in the lysine aldehyde-derived cross-links but generation of hydroxylysine aldehyde-derived cross-links. The latter were absent from the wild type and heterozygous mice. Glycosylation of hydroxylysine residues was moderately increased in the CypB null tendon. We found that CypB interacted with all lysyl hydroxylase isoforms (isoforms 1-3) and a putative lysyl hydroxylase-2 chaperone, 65-kDa FK506-binding protein. Tendon collagen in CypB null mice showed severe size and organizational abnormalities. The data indicate that CypB modulates collagen cross-linking by differentially affecting lysine hydroxylation in a site-specific manner, possibly via its interaction with lysyl hydroxylases and associated molecules. This study underscores the critical importance of collagen post-translational modifications in connective tissue formation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Tetraethylorthosilicate (TEOS) applied in the surface modification of hydroxyapatite to develop polydimethylsiloxane/hydroxyapatite composites.

PubMed

Bareiro, O; Santos, L A

2014-03-01

Nanometric hydroxyapatite (HAp) particles were modified with 5 or 10 wt.% tetraethylorthosilicate (TEOS) solutions in order to prepare polydimethylsiloxane/hydroxyapatite (PDMS/HAp) composites. The surface modification of the HAp particles was studied by transmission electron spectroscopy (TEM) and by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) equipment. The dispersion state of the modified particles in the PDMS matrix was also assessed by SEM. The composite phase composition was characterized by X-ray diffraction (XRD). The composite thermodynamic parameters of cross-linking were analyzed by differential scanning calorimetry (DSC). TEM micrographs and EDS spectra indicated evidence of silica-coating formation on the surface of modified HAp particles. SEM results showed that the HAp particles formed agglomerates in the PDMS matrix. It was found that the introduction of HAp particles into the PDMS changed the enthalpy of cross-linking and the temperature of the beginning of the cross-linking reaction. EDS results indicated that the surface modification of HAp produced composites showing thermodynamic parameters that were more similar to those of unfilled PDMS. Copyright © 2013 Elsevier B.V. All rights reserved.

Synthesis, DNA binding ability and anticancer activity of 2-heteroaryl substituted benzimidazoles linked pyrrolo[2,1-c][1,4]benzodiazepine conjugates.

PubMed

Kamal, Ahmed; Pogula, Praveen Kumar; Khan, Mohammed Naseer Ahmed; Seshadri, Bobburi Naga; Sreekanth, Kokkonda

2013-08-01

As a continuation of our efforts to develop the benzimidazole-PBD conjugates as potential anticancer agents, a series of heteroaryl substituted benzimidazole linked PBD conjugates has been synthesized and evaluated for their anticancer potential in 60 human cancer cell lines. Most of the compounds exhibited promising anticancer activity and interestingly, compounds 4c and 4d displayed significant activity in most of the cell lines tested. Whereas, compound 4e showed selectivity in renal cancer cells with GI50 values of <10 and 70 nM against RXF 393 and UO-31 cell lines, respectively. Further, these compounds also showed significant DNA-binding affinity by thermal denaturation study using duplex form of calf thymus (CT) DNA.

Discussion on LDPC Codes and Uplink Coding

NASA Technical Reports Server (NTRS)

Andrews, Ken; Divsalar, Dariush; Dolinar, Sam; Moision, Bruce; Hamkins, Jon; Pollara, Fabrizio

2007-01-01

This slide presentation reviews the progress that the workgroup on Low-Density Parity-Check (LDPC) for space link coding. The workgroup is tasked with developing and recommending new error correcting codes for near-Earth, Lunar, and deep space applications. Included in the presentation is a summary of the technical progress of the workgroup. Charts that show the LDPC decoder sensitivity to symbol scaling errors are reviewed, as well as a chart showing the performance of several frame synchronizer algorithms compared to that of some good codes and LDPC decoder tests at ESTL. Also reviewed is a study on Coding, Modulation, and Link Protocol (CMLP), and the recommended codes. A design for the Pseudo-Randomizer with LDPC Decoder and CRC is also reviewed. A chart that summarizes the three proposed coding systems is also presented.

Family Context, Mexican-Origin Adolescent Mothers' Parenting Knowledge, and Children's Subsequent Developmental Outcomes

PubMed Central

Jahromi, Laudan B.; Guimond, Amy B.; Umaña-Taylor, Adriana J.; Updegraff, Kimberly A.; Toomey, Russell B.

2014-01-01

This study examined parenting knowledge among Mexican-origin adolescent mothers (N = 191; M age = 16.26 years), family contextual factors associated with adolescents' parenting knowledge, and toddlers' (M age = 2.01 years) subsequent developmental outcomes. Data came from home interviews and direct child assessments. Adolescents both under- and over-estimated children's developmental timing, and showed differences in their knowledge of specific developmental domains. Instrumental support from mother figures was positively linked to adolescents' knowledge accuracy, whereas emotional support was negatively related to adolescents' knowledge confidence. Furthermore, whereas mother figures' autonomy-granting was positively linked to knowledge confidence, psychological control was associated with less accurate adolescent parenting knowledge. Toddlers of adolescents with more accurate knowledge showed positive developmental functioning. Intervention implications are discussed. PMID:24004448

Effects of adaptive dynamical linking in networked games

NASA Astrophysics Data System (ADS)

Yang, Zhihu; Li, Zhi; Wu, Te; Wang, Long

2013-10-01

The role of dynamical topologies in the evolution of cooperation has received considerable attention, as some studies have demonstrated that dynamical networks are much better than static networks in terms of boosting cooperation. Here we study a dynamical model of evolution of cooperation on stochastic dynamical networks in which there are no permanent partners to each agent. Whenever a new link is created, its duration is randomly assigned without any bias or preference. We allow the agent to adaptively adjust the duration of each link during the evolution in accordance with the feedback from game interactions. By Monte Carlo simulations, we find that cooperation can be remarkably promoted by this adaptive dynamical linking mechanism both for the game of pairwise interactions, such as the Prisoner's Dilemma game (PDG), and for the game of group interactions, illustrated by the public goods game (PGG). And the faster the adjusting rate, the more successful the evolution of cooperation. We also show that in this context weak selection favors cooperation much more than strong selection does. What is particularly meaningful is that the prosperity of cooperation in this study indicates that the rationality and selfishness of a single agent in adjusting social ties can lead to the progress of altruism of the whole population.

Divorce and eating behaviors: a 5-day within-subject study of preadolescent obesity risk.

PubMed

Mauskopf, Susan S; O'Leary, Allison K; Banihashemi, Adria; Weiner, Michelle; Cookston, Jeffrey T

2015-04-01

Obesity rates have more than doubled among children and have tripled among adolescents since the 1980s, and currently more than one third of children and adolescents are overweight or obese. Parental divorce is a time of family upheaval, yet little is known about the family processes that link family structure and obesity. The current study gathered a 5-day eating behavior questionnaire from 37 preadolescents (mean=10.26 years; standard deviation=1.32; 32.4% female) and one parent to explore whether marital status was linked to obesity risk behaviors (i.e., high consumption of sugar-sweetened beverages (SSBs), low consumption of produce, skipping breakfast, and eating dinners away from the home) and whether family context (e.g., parent time spent with child, parental acceptance, and family routines) mediated that link. Results showed that preadolescents in divorced families consumed more SSBs than preadolescents in married families, and there was a trend for less-frequent breakfast consumption among preadolescents in the divorced families. Of the three family context variables, only family routines explained the link between family structure and obesity risk. This study highlights the importance of family processes during divorce to understand the etiology and prevalence of child and adolescent obesity.

How people make friends in social networking sites—A microscopic perspective

NASA Astrophysics Data System (ADS)

Hu, Haibo; Wang, Xiaofan

2012-02-01

We study the detailed growth of a social networking site with full temporal information by examining the creation process of each friendship relation that can collectively lead to the macroscopic properties of the network. We first study the reciprocal behavior of users, and find that link requests are quickly responded to and that the distribution of reciprocation intervals decays in an exponential form. The degrees of inviters/accepters are slightly negatively correlative with reciprocation time. In addition, the temporal feature of the online community shows that the distributions of intervals of user behaviors, such as sending or accepting link requests, follow a power law with a universal exponent, and peaks emerge for intervals of an integral day. We finally study the preferential selection and linking phenomena of the social networking site and find that, for the former, a linear preference holds for preferential sending and reception, and for the latter, a linear preference also holds for preferential acceptance, creation, and attachment. Based on the linearly preferential linking, we put forward an analyzable network model which can reproduce the degree distribution of the network. The research framework presented in the paper could provide a potential insight into how the micro-motives of users lead to the global structure of online social networks.

Design and evaluation of moxifloxacin hydrochloride ocular inserts.

PubMed

Pawar, Pravin K; Katara, Rajesh; Majumdar, Dipak K

2012-03-01

The objective of the present investigation was to prepare and evaluate ocular inserts of moxifloxacin. An ocular insert was made from an aqueous dispersion of moxifloxacin, sodium alginate, polyvinyl alcohol, and dibutyl phthalate by the film casting method. The ocular insert (5.5 mm diameter) was cross-linked by CaCl2 and was coated with Eudragit S-100, RL-100, RS-100, E-100 or L-100. The in vitro drug drainage/permeation studies were carried out using an all-glass modified Franz diffusion cell. The drug concentration and mucoadhesion time of the ocular insert were found satisfactory. Cross-linking and coating with polymers extended the drainage from inserts. The cross-linked ocular insert coated with Eudragit RL-100 showed maximum drug permeation compared to other formulations.

Does Maternal Employment Following Childbirth Support or Inhibit Low-Income Children’s Long-Term Development?

PubMed Central

Coley, Rebekah Levine; Lombardi, Caitlin McPherran

2012-01-01

This study assessed whether previous findings linking early maternal employment to lower cognitive and behavioral skills among middle class and White children generalized to other groups. Using a representative sample of urban, low-income, predominantly African American and Hispanic families (n = 444), OLS regression and propensity score matching models assessed links between maternal employment in the two years after childbearing and children’s functioning at age 7. Children whose mothers were employed early, particularly in their first 8 months, showed enhanced socio-emotional functioning compared to peers whose mother remained nonemployed. Protective associations emerged for both part time and full time employment, and were driven by African American children, with neutral effects for Hispanics. Informal home-based child care also heightened positive links. PMID:22931466

Fiber-coupling efficiency of Gaussian-Schell model beams through an ocean to fiber optical communication link

NASA Astrophysics Data System (ADS)

Hu, Beibei; Shi, Haifeng; Zhang, Yixin

2018-06-01

We theoretically study the fiber-coupling efficiency of Gaussian-Schell model beams propagating through oceanic turbulence. The expression of the fiber-coupling efficiency is derived based on the spatial power spectrum of oceanic turbulence and the cross-spectral density function. Our work shows that the salinity fluctuation has a greater impact on the fiber-coupling efficiency than temperature fluctuation does. We can select longer λ in the "ocean window" and higher spatial coherence of light source to improve the fiber-coupling efficiency of the communication link. We also can achieve the maximum fiber-coupling efficiency by choosing design parameter according specific oceanic turbulence condition. Our results are able to help the design of optical communication link for oceanic turbulence to fiber sensor.

Mixed Transportation Network Design under a Sustainable Development Perspective

PubMed Central

Qin, Jin; Ni, Ling-lin; Shi, Feng

2013-01-01

A mixed transportation network design problem considering sustainable development was studied in this paper. Based on the discretization of continuous link-grade decision variables, a bilevel programming model was proposed to describe the problem, in which sustainability factors, including vehicle exhaust emissions, land-use scale, link load, and financial budget, are considered. The objective of the model is to minimize the total amount of resources exploited under the premise of meeting all the construction goals. A heuristic algorithm, which combined the simulated annealing and path-based gradient projection algorithm, was developed to solve the model. The numerical example shows that the transportation network optimized with the method above not only significantly alleviates the congestion on the link, but also reduces vehicle exhaust emissions within the network by up to 41.56%. PMID:23476142

Mixed transportation network design under a sustainable development perspective.

PubMed

Qin, Jin; Ni, Ling-lin; Shi, Feng

2013-01-01

A mixed transportation network design problem considering sustainable development was studied in this paper. Based on the discretization of continuous link-grade decision variables, a bilevel programming model was proposed to describe the problem, in which sustainability factors, including vehicle exhaust emissions, land-use scale, link load, and financial budget, are considered. The objective of the model is to minimize the total amount of resources exploited under the premise of meeting all the construction goals. A heuristic algorithm, which combined the simulated annealing and path-based gradient projection algorithm, was developed to solve the model. The numerical example shows that the transportation network optimized with the method above not only significantly alleviates the congestion on the link, but also reduces vehicle exhaust emissions within the network by up to 41.56%.

A method for modelling GP practice level deprivation scores using GIS

PubMed Central

Strong, Mark; Maheswaran, Ravi; Pearson, Tim; Fryers, Paul

2007-01-01

Background A measure of general practice level socioeconomic deprivation can be used to explore the association between deprivation and other practice characteristics. An area-based categorisation is commonly chosen as the basis for such a deprivation measure. Ideally a practice population-weighted area-based deprivation score would be calculated using individual level spatially referenced data. However, these data are often unavailable. One approach is to link the practice postcode to an area-based deprivation score, but this method has limitations. This study aimed to develop a Geographical Information Systems (GIS) based model that could better predict a practice population-weighted deprivation score in the absence of patient level data than simple practice postcode linkage. Results We calculated predicted practice level Index of Multiple Deprivation (IMD) 2004 deprivation scores using two methods that did not require patient level data. Firstly we linked the practice postcode to an IMD 2004 score, and secondly we used a GIS model derived using data from Rotherham, UK. We compared our two sets of predicted scores to "gold standard" practice population-weighted scores for practices in Doncaster, Havering and Warrington. Overall, the practice postcode linkage method overestimated "gold standard" IMD scores by 2.54 points (95% CI 0.94, 4.14), whereas our modelling method showed no such bias (mean difference 0.36, 95% CI -0.30, 1.02). The postcode-linked method systematically underestimated the gold standard score in less deprived areas, and overestimated it in more deprived areas. Our modelling method showed a small underestimation in scores at higher levels of deprivation in Havering, but showed no bias in Doncaster or Warrington. The postcode-linked method showed more variability when predicting scores than did the GIS modelling method. Conclusion A GIS based model can be used to predict a practice population-weighted area-based deprivation measure in the absence of patient level data. Our modelled measure generally had better agreement with the population-weighted measure than did a postcode-linked measure. Our model may also avoid an underestimation of IMD scores in less deprived areas, and overestimation of scores in more deprived areas, seen when using postcode linked scores. The proposed method may be of use to researchers who do not have access to patient level spatially referenced data. PMID:17822545

Feasibility study on cross-linked biopolymeric concrete encapsulating selenium glass wastes.

PubMed

Kim, Daeik; Park, Joon-Seok; Yen, Teh Fu

2012-08-01

Feasibility study was conducted to encapsulate the selenium (Se) contained in glass waste, using the biopolymer-modified concrete. Biopolymer has unique characteristics to provide the chemical sites to metals or toxic compounds through the three-dimensional cross-linked structure. Very minute amount of biopolymer enhanced the characteristics of cementitious material. The resulting biopolymeric composite with selenium glass waste showed 20% higher compressive strength than ordinary concrete and the lower leaching concentration than the equipment detection limit. For a qualitative measurement, X-ray diffraction (XRD; X-ray powder diffractogram) was used to characterize the biopolymeric concrete. The optimum waste content percentage with appropriate biopolymer concrete mixture ratio was identified for its possible commercial use.

The evolution of fairness through spite

PubMed Central

Forber, Patrick; Smead, Rory

2014-01-01

The presence of apparently irrational fair play in the ultimatum game remains a focal point for studies in the evolution of social behaviour. We investigate the role of negative assortment in the evolution of fair play in the ultimatum game. Spite—social behaviour that inflicts harm with no direct benefit to the actor—can evolve when it is disproportionally directed at individuals playing different strategies. The introduction of negative assortment alters the dynamics in a way that increases the chance fairness evolves, but at a cost: spite also evolves. Fairness is usually linked to cooperation and prosocial behaviour, but this study shows that it may have evolutionary links to harmful antisocial behaviour. PMID:24523265

Social Relationships and Health: A Flashpoint for Health Policy

PubMed Central

Umberson, Debra; Montez, Jennifer Karas

2011-01-01

Social relationships—both quantity and quality—affect mental health, health behavior, physical health, and mortality risk. Sociologists have played a central role in establishing the link between social relationships and health outcomes, identifying explanations for this link, and discovering social variation (e.g., by gender and race) at the population level. Studies show that social relationships have short- and long-term effects on health, for better and for worse, and that these effects emerge in childhood and cascade throughout life to foster cumulative advantage or disadvantage in health. This article describes key research themes in the study of social relationships and health, and it highlights policy implications suggested by this research. PMID:20943583

Evaluation and linking of effective parameters in particle-based models and continuum models for mixing-limited bimolecular reactions

NASA Astrophysics Data System (ADS)

Zhang, Yong; Papelis, Charalambos; Sun, Pengtao; Yu, Zhongbo

2013-08-01

Particle-based models and continuum models have been developed to quantify mixing-limited bimolecular reactions for decades. Effective model parameters control reaction kinetics, but the relationship between the particle-based model parameter (such as the interaction radius R) and the continuum model parameter (i.e., the effective rate coefficient Kf) remains obscure. This study attempts to evaluate and link R and Kf for the second-order bimolecular reaction in both the bulk and the sharp-concentration-gradient (SCG) systems. First, in the bulk system, the agent-based method reveals that R remains constant for irreversible reactions and decreases nonlinearly in time for a reversible reaction, while mathematical analysis shows that Kf transitions from an exponential to a power-law function. Qualitative link between R and Kf can then be built for the irreversible reaction with equal initial reactant concentrations. Second, in the SCG system with a reaction interface, numerical experiments show that when R and Kf decline as t-1/2 (for example, to account for the reactant front expansion), the two models capture the transient power-law growth of product mass, and their effective parameters have the same functional form. Finally, revisiting of laboratory experiments further shows that the best fit factor in R and Kf is on the same order, and both models can efficiently describe chemical kinetics observed in the SCG system. Effective model parameters used to describe reaction kinetics therefore may be linked directly, where the exact linkage may depend on the chemical and physical properties of the system.

Efficacy and safety of newly developed cross-linked dextran gel injection for glans penis augmentation with a novel technique

PubMed Central

Yang, Dae Yul; Ko, Kyungtae; Lee, Seong Ho; Moon, Du Geon; Kim, Jong Wook; Lee, Won Ki

2018-01-01

There is no safe and effective standard method for glans penis augmentation. Furthermore, there has been scant research on glans penis augmentation due to a poor understanding of glans anatomy, technical difficulty, and a lack of suitable substances for augmentation. Cross-linked dextran gel is a newly developed filler for soft-tissue augmentation. We evaluated the efficacy and safety of using a novel technique to inject cross-linked dextran gel for glans penis augmentation during a 24-week follow-up study. This prospective, single-arm, multicenter study enrolled twenty healthy adult men who underwent glans penis augmentation between June and August 2013. Cross-linked dextran gel was injected into the glans penis using a simple and easy technique. The sizes of the glans penis and individual satisfaction were assessed. Any adverse event was also reported. A total of 18 individuals were analyzed; two of them were lost to follow-up. The mean procedure time and injected volume were about 30 min and 6.6 ± 0.9 ml, respectively. The mean surface areas of the glans at baseline and 24 weeks were 20.0 ± 3.5 cm2 and 33.6 ± 5.4 cm2, respectively, representing a mean increase of 68.7% ± 14.0% (P < 0.001). Sixteen individuals (88.9%) were satisfied with the outcomes, and none were dissatisfied. There were no serious adverse events during the study. Cross-linked dextran gel injection for glans penis augmentation was easy and showed a significant augmentative effect on the glans penis, good durability, and was well tolerated without serious adverse events. Therefore, cross-linked dextran gel injection may be an effective, new technique for glans penis augmentation. PMID:28303807

In vivo evaluation of folate decorated cross-linked micelles for the delivery of platinum anticancer drugs.

PubMed

Eliezar, Jeaniffer; Scarano, Wei; Boase, Nathan R B; Thurecht, Kristofer J; Stenzel, Martina H

2015-02-09

The biodistribution of micelles with and without folic acid targeting ligands were studied using a block copolymer consisting of acrylic acid (AA) and polyethylene glycol methyl ether acrylate (PEGMEA) blocks. The polymers were prepared using RAFT polymerization in the presence of a folic acid functionalized RAFT agent. Oxoplatin was conjugated onto the acrylic acid block to form amphiphilic polymers which, when diluted in water, formed stable micelles. In order to probe the in vivo stability, a selection of micelles were cross-linked using 1,8-diamino octane. The sizes of the micelles used in this study range between 75 and 200 nm, with both spherical and worm-like conformation. The effects of cross-linking, folate conjugation and different conformation on the biodistribution were studied in female nude mice (BALB/c) following intravenous injection into the tail vein. Using optical imaging to monitor the fluorophore-labeled polymer, the in vivo biodistribution of the micelles was monitored over a 48 h time-course after which the organs were removed and evaluated ex vivo. These experiments showed that both cross-linking and conjugation with folic acid led to increased fluorescence intensities in the organs, especially in the liver and kidneys, while micelles that are not conjugated with folate and not cross-linked are cleared rapidly from the body. Higher accumulation in the spleen, liver, and kidneys was also observed for micelles with worm-like shapes compared to the spherical micelles. While the various factors of cross-linking, micelle shape, and conjugation with folic acid all contribute separately to prolong the circulation time of the micelle, optimization of these parameters for drug delivery devices could potentially overcome adverse effects such as liver and kidney toxicity.

Structural analysis of fructans from Agave americana grown in South Africa for spirit production.

PubMed

Ravenscroft, Neil; Cescutti, Paola; Hearshaw, Meredith A; Ramsout, Ronica; Rizzo, Roberto; Timme, Elizabeth M

2009-05-27

Fructans isolated from Agave americana grown in South Africa are currently used for spirit production. Structural studies on water-soluble fructans were performed to facilitate the development of other applications including its use as a prebiotic. Acid hydrolysis followed by HPAEC-PAD analysis confirmed that the fructan was composed of glucose and fructose, and size analysis by HPAEC-PAD and size exclusion chromatography indicated that the saccharides have a DP range from 6 to 50. An average DP of 14 was estimated by (1)H NMR analysis. Linkage analysis and ESI-MS studies suggest that A. americana has a neofructan structure consisting of a central sucrose to which (2 → 1)- and (2 → 6)-linked β-D-Fruf chains are attached. The (2 → 1)-linked units extend from C-1 of Fru and C-6 of glucose, whereas the (2 → 6)-linked β-D-Fruf units are attached to C-6 of the central Fru. This structure accounts for the presence of equimolar amounts of 1,6-linked Glu and 1,2,6-linked Fru found in linkage analysis and the multiplicity of the NMR signals observed. Detailed ESI-MS studies were performed on fructan fractions: native, periodate oxidized/reduced, and permethylated oligomers. These derivatizations introduced mass differences between Glc and Fru following oxidation and between 1,2-, 1,6-, 2,6-, and 1,2,6-linked units after methylation. Thus, ESI-MS showed the presence of a single Glc per fructan chain and that it is predominantly internal, rather than terminal as found in inulin. These structural features were confirmed by the use of 1D and 2D NMR experiments.

An Accurate Link Correlation Estimator for Improving Wireless Protocol Performance

PubMed Central

Zhao, Zhiwei; Xu, Xianghua; Dong, Wei; Bu, Jiajun

2015-01-01

Wireless link correlation has shown significant impact on the performance of various sensor network protocols. Many works have been devoted to exploiting link correlation for protocol improvements. However, the effectiveness of these designs heavily relies on the accuracy of link correlation measurement. In this paper, we investigate state-of-the-art link correlation measurement and analyze the limitations of existing works. We then propose a novel lightweight and accurate link correlation estimation (LACE) approach based on the reasoning of link correlation formation. LACE combines both long-term and short-term link behaviors for link correlation estimation. We implement LACE as a stand-alone interface in TinyOS and incorporate it into both routing and flooding protocols. Simulation and testbed results show that LACE: (1) achieves more accurate and lightweight link correlation measurements than the state-of-the-art work; and (2) greatly improves the performance of protocols exploiting link correlation. PMID:25686314

Predicting missing links and identifying spurious links via likelihood analysis

NASA Astrophysics Data System (ADS)

Pan, Liming; Zhou, Tao; Lü, Linyuan; Hu, Chin-Kun

2016-03-01

Real network data is often incomplete and noisy, where link prediction algorithms and spurious link identification algorithms can be applied. Thus far, it lacks a general method to transform network organizing mechanisms to link prediction algorithms. Here we use an algorithmic framework where a network’s probability is calculated according to a predefined structural Hamiltonian that takes into account the network organizing principles, and a non-observed link is scored by the conditional probability of adding the link to the observed network. Extensive numerical simulations show that the proposed algorithm has remarkably higher accuracy than the state-of-the-art methods in uncovering missing links and identifying spurious links in many complex biological and social networks. Such method also finds applications in exploring the underlying network evolutionary mechanisms.

Predicting missing links and identifying spurious links via likelihood analysis

PubMed Central

Pan, Liming; Zhou, Tao; Lü, Linyuan; Hu, Chin-Kun

2016-01-01

Real network data is often incomplete and noisy, where link prediction algorithms and spurious link identification algorithms can be applied. Thus far, it lacks a general method to transform network organizing mechanisms to link prediction algorithms. Here we use an algorithmic framework where a network’s probability is calculated according to a predefined structural Hamiltonian that takes into account the network organizing principles, and a non-observed link is scored by the conditional probability of adding the link to the observed network. Extensive numerical simulations show that the proposed algorithm has remarkably higher accuracy than the state-of-the-art methods in uncovering missing links and identifying spurious links in many complex biological and social networks. Such method also finds applications in exploring the underlying network evolutionary mechanisms. PMID:26961965

Money Now, Money Later: Linking Time Discounting and Criminal Convictions in the Cambridge Study in Delinquent Development.

PubMed

Piquero, Alex R; Farrington, David P; Jennings, Wesley G

2018-04-01

Two prominent criminological theories offer time discounting, or the preference for an immediate reward over a later one, as a central part of understanding involvement in criminal activity. Yet, there exist only a few studies investigating this issue, and they are limited in a few respects. The current study extends prior work in this area by using multiple measures of time discounting collected at three different periods of the life course to examine the link to criminal offending into late middle adulthood in the Cambridge Study in Delinquent Development. Results show that greater time discounting is positively related to a higher number of criminal convictions by late middle adulthood, and this effect remains after controlling for early life-course individual and environmental risk in a multivariate framework. Study limitations and implications are also discussed.

X-linked juvenile retinoschisis in females and response to carbonic anhydrase inhibitors: case report and review of the literature.

PubMed

Ali, Syed; Seth, Rajeev

2013-01-01

A 63 year old woman was referred to the retina clinic after her vision failed to improve in her left eye after cataract surgery. X-linked retinoschisis was diagnosed in the patient after her retina exam revealed an area of retinoschisis and a foveal cyst. The OCT confirmed the macular cyst and the ERG showed loss of B waves. The florescein angiogram showed no significant perifoveal leakage. Her foveal cyst resolved after treatment with carbonic anhydrase inhibitors. The patient's son was examined and his ophthalmologic exam, ERG and imaging findings were consistent with X-linked retinoschisis. However, his bilateral foveal cysts did not respond to treatment with carbonic anhydrase inhibitors. X-linked retinoschisis is a very rare disease in women due to its X-linked recessive inheritance and the foveal cysts associated with it can respond to carbonic anhydrase inhibitors.

Effect of Simvastatin, Coenzyme Q10, Resveratrol, Acetylcysteine and Acetylcarnitine on Mitochondrial Respiration.

PubMed

Fišar, Z; Hroudová, J; Singh, N; Kopřivová, A; Macečková, D

2016-01-01

Some therapeutic and/or adverse effects of drugs may be related to their effects on mitochondrial function. The effects of simvastatin, resveratrol, coenzyme Q10, acetylcysteine, and acetylcarnitine on Complex I-, Complex II-, or Complex IV-linked respiratory rate were determined in isolated brain mitochondria. The protective effects of these biologically active compounds on the calcium-induced decrease of the respiratory rate were also studied. We observed a significant inhibitory effect of simvastatin on mitochondrial respiration (IC50 = 24.0 μM for Complex I-linked respiration, IC50 = 31.3 μM for Complex II-linked respiration, and IC50 = 42.9 μM for Complex IV-linked respiration); the inhibitory effect of resveratrol was found at very high concentrations (IC50 = 162 μM for Complex I-linked respiration, IC50 = 564 μM for Complex II-linked respiration, and IC50 = 1454 μM for Complex IV-linked respiration). Concentrations required for effective simvastatin- or resveratrol-induced inhibition of mitochondrial respiration were found much higher than concentrations achieved under standard dosing of these drugs. Acetylcysteine and acetylcarnitine did not affect the oxygen consumption rate of mitochondria. Coenzyme Q10 induced an increase of Complex I-linked respiration. The increase of free calcium ions induced partial inhibition of the Complex I+II-linked mitochondrial respiration, and all tested drugs counteracted this inhibition. None of the tested drugs showed mitochondrial toxicity (characterized by respiratory rate inhibition) at drug concentrations achieved at therapeutic drug intake. Resveratrol, simvastatin, and acetylcarnitine had the greatest neuroprotective potential (characterized by protective effects against calcium-induced reduction of the respiratory rate).

DEVELOPING INDICATORS OF NITROGEN SOURCE IN COASTAL ECOSYSTEMS

EPA Science Inventory

Several studies have linked stable isotope ratios of biota to nitrogen source. In particular, ribbed mussels show promise as sensitive indicators of the origins of nitrogen inputs to coastal ecosystems. Here we expand on previous work which demonstrated that mussel isotope ratios...

Renewable Selections

ERIC Educational Resources Information Center

Pye, Linda

2009-01-01

Studies show that well designed interiors can influence education profoundly. Awareness of the importance of sustainability and its role within the learning environment is growing. Research indicates a possible link between sustainable facilities and better learning outcomes. Education is one of the fastest growing markets for green buildings and…

Lexical Processing Skill in College-Age Resilient Readers

ERIC Educational Resources Information Center

Welcome, Suzanne E.; Chiarello, Christine; Halderman, Laura K.; Leonard, Christiana M.

2009-01-01

Despite an extensive literature linking individual differences in phonological processing to reading ability, some adults show normal text comprehension abilities despite poor pseudoword reading (Jackson & Doellinger (2002). "Journal of Educational Psychology," 94, 64-78). This study was undertaken to investigate differences between these…

Coupling of link- and node-ordering in the coevolving voter model.

PubMed

Toruniewska, J; Kułakowski, K; Suchecki, K; Hołyst, J A

2017-10-01

We consider the process of reaching the final state in the coevolving voter model. There is a coevolution of state dynamics, where a node can copy a state from a random neighbor with probabilty 1-p and link dynamics, where a node can rewire its link to another node of the same state with probability p. That exhibits an absorbing transition to a frozen phase above a critical value of rewiring probability. Our analytical and numerical studies show that in the active phase mean values of magnetization of nodes n and links m tend to the same value that depends on initial conditions. In a similar way mean degrees of spins up and spins down become equal. The system obeys a special statistical conservation law since a linear combination of both types magnetizations averaged over many realizations starting from the same initial conditions is a constant of motion: Λ≡(1-p)μm(t)+pn(t)=const., where μ is the mean node degree. The final mean magnetization of nodes and links in the active phase is proportional to Λ while the final density of active links is a square function of Λ. If the rewiring probability is above a critical value and the system separates into disconnected domains, then the values of nodes and links magnetizations are not the same and final mean degrees of spins up and spins down can be different.

Analysis of Nuclear Factor-κB (NF-κB) Essential Modulator (NEMO) Binding to Linear and Lysine-linked Ubiquitin Chains and Its Role in the Activation of NF-κB*

PubMed Central

Kensche, Tobias; Tokunaga, Fuminori; Ikeda, Fumiyo; Goto, Eiji; Iwai, Kazuhiro; Dikic, Ivan

2012-01-01

Nuclear factor-κB (NF-κB) essential modulator (NEMO), a component of the inhibitor of κB kinase (IKK) complex, controls NF-κB signaling by binding to ubiquitin chains. Structural studies of NEMO provided a rationale for the specific binding between the UBAN (ubiquitin binding in ABIN and NEMO) domain of NEMO and linear (Met-1-linked) di-ubiquitin chains. Full-length NEMO can also interact with Lys-11-, Lys-48-, and Lys-63-linked ubiquitin chains of varying length in cells. Here, we show that purified full-length NEMO binds preferentially to linear ubiquitin chains in competition with lysine-linked ubiquitin chains of defined length, including long Lys-63-linked deca-ubiquitins. Linear di-ubiquitins were sufficient to activate both the IKK complex in vitro and to trigger maximal NF-κB activation in cells. In TNFα-stimulated cells, NEMO chimeras engineered to bind exclusively to Lys-63-linked ubiquitin chains mediated partial NF-κB activation compared with cells expressing NEMO that binds to linear ubiquitin chains. We propose that NEMO functions as a high affinity receptor for linear ubiquitin chains and a low affinity receptor for long lysine-linked ubiquitin chains. This phenomenon could explain quantitatively distinct NF-κB activation patterns in response to numerous cell stimuli. PMID:22605335

The effect of riboflavin/UVA cross-linking on anti-degeneration and promoting angiogenic capability of decellularized liver matrix.

PubMed

Xiang, Junxi; Liu, Peng; Zheng, Xinglong; Dong, Dinghui; Fan, Shujuan; Dong, Jian; Zhang, Xufeng; Liu, Xuemin; Wang, Bo; Lv, Yi

2017-10-01

Weak mechanical property and unstable degradation rate limited the application of decellularized liver matrix in tissue engineering. The aim of this study was to explore a new method for improving the mechanical properties, anti-degeneration and angiogenic capability of decellularized liver matrix. This was achieved by a novel approach using riboflavin/ultraviolet A treatment to induce collagen cross-linking of decellularized matrix. Histological staining and scanning electron microscope showed that the diameter of cross-linked fibers significantly increased compared with the control group. The average peak load and Young's modulus of decellularized matrix were obviously improved after cross-linking. Then we implanted the modified matrix into the rat hepatic injury model to test the anti-degeneration and angiogenic capability of riboflavin/UVA cross-linked decellularized liver scaffolds in vivo. The results indicated that cross-linked scaffolds degrade more slowly than those in the control group. In the experiment group, average microvessel density in the implanted matrix was higher than that in the control group since the first week after implantation. In conclusion, we initiated the method to improve the biomechanical properties of decellularized liver scaffolds by riboflavin/UVA cross-linking, and more importantly, its improvement on anti-degeneration and angiogenesis was identified. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2662-2669, 2017. © 2017 Wiley Periodicals, Inc.

A group evolving-based framework with perturbations for link prediction

NASA Astrophysics Data System (ADS)

Si, Cuiqi; Jiao, Licheng; Wu, Jianshe; Zhao, Jin

2017-06-01

Link prediction is a ubiquitous application in many fields which uses partially observed information to predict absence or presence of links between node pairs. The group evolving study provides reasonable explanations on the behaviors of nodes, relations between nodes and community formation in a network. Possible events in group evolution include continuing, growing, splitting, forming and so on. The changes discovered in networks are to some extent the result of these events. In this work, we present a group evolving-based characterization of node's behavioral patterns, and via which we can estimate the probability they tend to interact. In general, the primary aim of this paper is to offer a minimal toy model to detect missing links based on evolution of groups and give a simpler explanation on the rationality of the model. We first introduce perturbations into networks to obtain stable cluster structures, and the stable clusters determine the stability of each node. Then fluctuations, another node behavior, are assumed by the participation of each node to its own belonging group. Finally, we demonstrate that such characteristics allow us to predict link existence and propose a model for link prediction which outperforms many classical methods with a decreasing computational time in large scales. Encouraging experimental results obtained on real networks show that our approach can effectively predict missing links in network, and even when nearly 40% of the edges are missing, it also retains stationary performance.

Collagen cross-link excretion during space flight and bed rest

NASA Technical Reports Server (NTRS)

Smith, S. M.; Nillen, J. L.; Leblanc, A.; Lipton, A.; Demers, L. M.; Lane, H. W.; Leach, C. S.; LeBlanc, A. (Principal Investigator)

1998-01-01

Extended exposure to weightlessness results in bone loss. However, little information exists as to the precise nature or time course of this bone loss. Bone resorption results in the release of collagen breakdown products, including N-telopeptide and the pyridinium (PYD) cross-links, pyridinoline and deoxypyridinoline. Urinary pyridinoline and deoxypyridinoline are known to increase during bed rest. We assessed excretion of PYD cross-links and N-telopeptide before, during, and after long (28-day, 59-day, and 84-day) Skylab missions, as well as during short (14-day) and long (119-day) bed-rest studies. During space flight, the urinary cross-link excretion level was twice those observed before flight. Urinary excretion levels of the collagen breakdown products were also 40-50% higher, during short and long bed rest, than before. These results clearly show that the changes in bone metabolism associated with space flight involve increased resorption. The rate of response (i.e. within days to weeks) suggests that alterations in bone metabolism are an early effect of weightlessness. These studies are important for a better understanding of bone metabolism in space crews and in those who are bedridden.

Preparation of PVA membrane for immobilization of GOD for glucose biosensor.

PubMed

Kumar, Jitendra; D'Souza, S F

2008-03-15

A membrane was prepared using polyvinyl alcohol (PVA) with low and high degree of polymerization (DOP), acetone, benzoic acid (BA) and was cross-linked by UV treatment. Membrane composition was optimized on the basis of swelling index. Membrane prepared with 12% low DOP and 8% high DOP of PVA, 2% BA, dissolved in buffer containing 20% acetone and cross-linked with UV treatment exhibited lower swelling index. Fourier transform infrared (FTIR) study of the membranes showed appearance of a strong band at approximately 2337 cm(-1) when UV was used for cross-linking in the presence of benzoic acid. Scanning electron microscope (SEM) study revealed that membrane cross-linked with UV treatment was smoother. Glucose oxidase (GOD)-PVA membrane was associated with the dissolved oxygen (DO) probe for biosensor reading. Glucose was detected on the basis of depletion of oxygen, when immobilized GOD oxidizes glucose to gluconolactone. A wide detection range, 0.9-225 mg/dl was estimated from the linear range of calibration plot of biosensor reading. Membranes were reused for 32 reactions without significant loss of activity and stored for 30 days (approximately 90% activity) at 4 degrees C. Membranes were also used with real blood samples.

Links Between Sibling Experiences and Romantic Competence from Adolescence Through Young Adulthood.

PubMed

Doughty, Susan E; Lam, Chun Bun; Stanik, Christine E; McHale, Susan M

2015-11-01

Although previous research has linked sibling relationship experiences to youth's social competencies with peers, we know little about the role of siblings in youth's romantic relationship experiences. Drawing on data from a longitudinal sample of 190 families, this study examined the links between sibling experiences and the development of perceived romantic competence from early adolescence into young adulthood (ages 12-20). The data were collected from 373 youth (50.7 % female) in home interviews on up to five annual occasions. Multi-level models tested the moderating role of sibling gender constellation in romantic competence development and the links between (changes in) sibling intimacy and conflict, and romantic competence. The results revealed that youth with same-sex siblings showed no change in their perceived romantic competence, but those with opposite-sex siblings exhibited increases in romantic competence over time. Controlling for parent-child intimacy, at times when youth reported more sibling intimacy, they also reported greater romantic competence, and youth with higher cross-time average sibling conflict were lower in romantic competence, on average. This study illustrates that sibling experiences remain important in social development into early adulthood and suggests directions for application and future research.

Links between Sibling Experiences and Romantic Competence from Adolescence through Young Adulthood

PubMed Central

Doughty, Susan E.; Lam, Chun Bun; Stanik, Christine E.; McHale, Susan M.

2014-01-01

Although previous research has linked sibling relationship experiences to youth’s social competencies with peers, we know little about the role of siblings in youth’s romantic relationship experiences. Drawing on data from a longitudinal sample of 190 families, this study examined the links between sibling experiences and the development of perceived romantic competence from early adolescence into young adulthood (ages 12 to 20). The data were collected from 373 youth (50.7% female) in home interviews on up to 5 annual occasions. Multi-level models tested the moderating role of sibling gender constellation in romantic competence development and the links between (changes in) sibling intimacy and conflict, and romantic competence. The results revealed that youth with same-sex siblings showed no change in their perceived romantic competence, but those with opposite-sex siblings exhibited increases in romantic competence over time. Controlling for parent-child intimacy, at times when youth reported more sibling intimacy, they also reported greater romantic competence, and youth with higher cross-time average sibling conflict were lower in romantic competence, on average. This study illustrates that sibling experiences remain important in social development into early adulthood and suggests directions for application and future research. PMID:25183625

Perceived discrimination predicts increased support for political rights and life satisfaction mediated by ethnic identity: A longitudinal analysis.

PubMed

Stronge, Samantha; Sengupta, Nikhil K; Barlow, Fiona Kate; Osborne, Danny; Houkamau, Carla A; Sibley, Chris G

2016-07-01

The aim of the current research is to test predictions derived from the rejection-identification model and research on collective action using cross-sectional (Study 1) and longitudinal (Study 2) methods. Specifically, an integration of these 2 literatures suggests that recognition of discrimination can have simultaneous positive relationships with well-being and engagement in collective action via the formation of a strong ingroup identity. We test these predictions in 2 studies using data from a large national probability sample of Māori (the indigenous peoples of New Zealand), collected as part of the New Zealand Attitudes and Values Study (Ns for Study 1 and 2 were 1,981 and 1,373, respectively). Consistent with the extant research, Study 1 showed that perceived discrimination was directly linked with decreased life satisfaction, but indirectly linked with increased life satisfaction through higher levels of ethnic identification. Perceived discrimination was also directly linked with increased support for Māori rights and indirectly linked with increased support for Māori rights through higher levels of ethnic identification. Study 2 replicated these findings using longitudinal data and identified multiple bidirectional paths between perceived discrimination, ethnic identity, well-being, and support for collective action. These findings replicate and extend the rejection-identification model in a novel cultural context by demonstrating via cross-sectional (Study 1) and longitudinal (Study 2) analyses that the recognition of discrimination can both motivate support for political rights and increase well-being by strengthening ingroup identity. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Hydrogels Prepared from Cross-Linked Nanofibrillated Cellulose

Treesearch

Sandeep S. Nair; J.Y. Zhu; Yulin Deng; Arthur J. Ragauskas

2014-01-01

Nanocomposite hydrogels were developed by cross-linking nanofibrillated cellulose with poly(methyl vinyl ether-co-maleic acid) and polyethylene glycol. The cross-linked hydrogels showed enhanced water absorption and gel content with the addition of nanocellulose. In addition, the thermal stability, mechanical strength, and modulus increased with an increase in the...

Ion Exchange Equilibrium and Kinetic Properties of Polyacrylate Films and Applications to Chemical Analysis and Environmental Decontamination

NASA Technical Reports Server (NTRS)

Tanner, Stephen P.

1997-01-01

One of the goals of the original proposal was to study how cross-linking affects the properties of an ion exchange material(IEM) developed at Lewis Research Center. However, prior to the start of this work, other workers at LERC investigated the effect of cross-linking on the properties of this material. Other than variation in the ion exchange capacity, the chemical characteristics were shown to be independent of the cross-linking agent, and the degree of cross-linking. New physical forms of the film were developed (film, supported film, various sizes of beads, and powder). All showed similar properties with respect to ion exchange equilibria but the kinetics of ion exchange depended on the surface area per unit mass; the powder form of the IEM exchanging much more rapidly than the other forms. The research performed under this grant was directed towards the application of the IEM to the analysis of metal ions at environmental concentrations.

Tribology of alternative bearings.

PubMed

Fisher, John; Jin, Zhongmin; Tipper, Joanne; Stone, Martin; Ingham, Eileen

2006-12-01

The tribological performance and biological activity of the wear debris produced has been compared for highly cross-linked polyethylene, ceramic-on-ceramic, metal-on-metal, and modified metal bearings in a series of in vitro studies from a single laboratory. The functional lifetime demand of young and active patients is 10-fold greater than the estimated functional lifetime of traditional polyethylene. There is considerable interest in using larger diameter heads in these high demand patients. Highly cross-linked polyethylene show a four-fold reduction in functional biological activity. Ceramic-on-ceramic bearings have the lowest wear rates and least reactive wear debris. The functional biological activity is 20-fold lower than with highly cross-linked polyethylene. Hence, ceramic-on-ceramic bearings address the tribological lifetime demand of highly active patients. Metal-on-metal bearings have substantially lower wear rates than highly cross-linked polyethylene and wear decreases with head diameter. Bedding in wear is also lower with reduced radial clearance. Differential hardness ceramic-on-metal bearings and the application of ceramic-like coatings reduce metal wear and ion levels.

The role of neutrophil gelatinase associated lipocalin (NGAL) as biological constituent linking depression and cardiovascular disease.

PubMed

Gouweleeuw, L; Naudé, P J W; Rots, M; DeJongste, M J L; Eisel, U L M; Schoemaker, R G

2015-05-01

Depression is more common in patients with cardiovascular disease than in the general population. Conversely, depression is a risk factor for developing cardiovascular disease. Comorbidity of these two pathologies worsens prognosis. Several mechanisms have been indicated in the link between cardiovascular disease and depression, including inflammation. Systemic inflammation can have long-lasting effects on the central nervous system, which could be associated with depression. NGAL is an inflammatory marker and elevated plasma levels are associated with both cardiovascular disease and depression. While patients with depression show elevated NGAL levels, in patients with comorbid heart failure, NGAL levels are significantly higher and associated with depression scores. Systemic inflammation evokes NGAL expression in the brain. This is considered a proinflammatory effect as it is involved in microglia activation and reactive astrocytosis. Animal studies support a direct link between NGAL and depression/anxiety associated behavior. In this review we focus on the role of NGAL in linking depression and cardiovascular disease. Copyright © 2015 Elsevier Inc. All rights reserved.

Protein analysis by 31p NMR spectroscopy in ionic liquid: quantitative determination of enzymatically created cross-links.

PubMed

Monogioudi, Evanthia; Permi, Perttu; Filpponen, Ilari; Lienemann, Michael; Li, Bin; Argyropoulos, Dimitris; Buchert, Johanna; Mattinen, Maija-Liisa

2011-02-23

Cross-linking of β-casein by Trichoderma reesei tyrosinase (TrTyr) and Streptoverticillium mobaraense transglutaminase (Tgase) was analyzed by (31)P nuclear magnetic resonance (NMR) spectroscopy in ionic liquid (IL). According to (31)P NMR, 91% of the tyrosine side chains were cross-linked by TrTyr at high dosages. When Tgase was used, no changes were observed because a different cross-linking mechanism was operational. However, this verified the success of the phosphitylation of phenolics within the protein matrix in the IL. Atomic force microscopy (AFM) in solid state showed that disk-shaped nanoparticles were formed in the reactions with average diameters of 80 and 20 nm for TrTyr and Tgase, respectively. These data further advance the current understanding of the action of tyrosinases on proteins on molecular and chemical bond levels. Quantitative (31)P NMR in IL was shown to be a simple and efficient method for the study of protein modification.

Quantitative Raman characterization of cross-linked collagen thin films as a model system for diagnosing early osteoarthritis

NASA Astrophysics Data System (ADS)

Wang, Chao; Durney, Krista M.; Fomovsky, Gregory; Ateshian, Gerard A.; Vukelic, Sinisa

2016-03-01

The onset of osteoarthritis (OA)in articular cartilage is characterized by degradation of extracellular matrix (ECM). Specifically, breakage of cross-links between collagen fibrils in the articular cartilage leads to loss of structural integrity of the bulk tissue. Since there are no broadly accepted, non-invasive, label-free tools for diagnosing OA at its early stage, Raman spectroscopyis therefore proposed in this work as a novel, non-destructive diagnostic tool. In this study, collagen thin films were employed to act as a simplified model system of the cartilage collagen extracellular matrix. Cross-link formation was controlled via exposure to glutaraldehyde (GA), by varying exposure time and concentration levels, and Raman spectral information was collected to quantitatively characterize the cross-link assignments imparted to the collagen thin films during treatment. A novel, quantitative method was developed to analyze the Raman signal obtained from collagen thin films. Segments of Raman signal were decomposed and modeled as the sum of individual bands, providing an optimization function for subsequent curve fitting against experimental findings. Relative changes in the concentration of the GA-induced pyridinium cross-links were extracted from the model, as a function of the exposure to GA. Spatially resolved characterization enabled construction of spectral maps of the collagen thin films, which provided detailed information about the variation of cross-link formation at various locations on the specimen. Results showed that Raman spectral data correlate with glutaraldehyde treatment and therefore may be used as a proxy by which to measure loss of collagen cross-links in vivo. This study proposes a promising system of identifying onset of OA and may enable early intervention treatments that may serve to slow or prevent osteoarthritis progression.

Comparative study of indirect immunofluorescence, enzyme-linked immunosorbent assay, and the Tzanck smear test for the diagnosis of pemphigus.

PubMed

Zhou, Tingting; Fang, Siyue; Li, Chunlei; Hua, Hong

2016-11-01

Pemphigus is one of the potentially fatal autoimmune blistering diseases. An early and accurate diagnosis is important for prognosis and therapy. It may be difficult to diagnosis based on clinical grounds alone. Direct and indirect immunofluorescence, enzyme-linked immunosorbent assay, the Tzanck smear test, or histopathology are all available for the diagnosis of pemphigus. However, there are no generally accepted diagnostic criteria for the diagnosis of this condition at present. To evaluate the diagnostic value of indirect immunofluorescence, enzyme-linked immunosorbent assay, and the Tzanck smear test for the diagnosis of pemphigus in dental clinics. A single-center retrospective study was conducted, and the clinical data of 33 patients with pemphigus and 61 controls were collected and analyzed from the Department of Oral Medicine, Peking University School of Stomatology, during 2010-2014. The sensitivities and specificities of indirect immunofluorescence, enzyme-linked immunosorbent assay, and the Tzanck smear test were calculated and compared in two groups. Sensitivities for the Tzanck smear test, indirect immunofluorescence, and enzyme-linked immunosorbent assay were 96.7%, 84.8%, and 84.8%, respectively, whereas the specificities of these tests were 60%, 91.8%, and 96.7%, respectively. The serial tests for the Tzanck smear test and enzyme-linked immunosorbent assay showed 82% sensitivity and 98.7% specificity. The serial test for the Tzanck smear test and enzyme-linked immunosorbent assay may represent a simple, rapid, and reliable way to definitive diagnosis of pemphigus. It is recommended as a common test for the diagnosis of pemphigus in dental clinics. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Tumor Necrosis Factor-Alpha Gene Promoter Region Polymorphism and the Risk of Coronary Heart Disease

PubMed Central

Asifa, Gul Zareen; Kazmi, Syed Ali Raza; Javed, Qamar

2013-01-01

Background. Tumor necrosis factor-alpha (TNF-α) gene polymorphisms have been implicated in the manifestation of atherosclerosis. Controversy exists regarding the link between the cytokine's variant genotype and CHD among different ethnic groups. There have been fewer studies on the TNF-α gene −1031T>C and −863C>A polymorphisms in relation to CHD. Therefore, the current study was designed to investigate the association of the TNF-α gene −1031T>C and −863C>A polymorphisms with CHD in a Pakistani population. Methods. Patients with CHD (n = 310) and healthy individuals (n = 310) were enrolled in this study. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results. A significant difference was observed in the −863C>A polymorphism between patients with CHD and control subjects (P < 0.0001). CHD risk was positively associated with the variant allele −863A (P < 0.0001) in the study subjects. There was no significant link between the −1031T>C polymorphism and CHD risk in the study population. Haplotypes A-T and A-C of the TNF-alpha gene loci at −863 and −1031 showed higher frequency in the patient group compared with controls (P < 0.05). Conclusion. The TNF-α  −863C>A gene polymorphism was associated with the pathogenesis of CHD while the −1031T>C polymorphism did not show any link with the disease in a Pakistani population. PMID:24381514

Influence of cross-link structure, density and mechanical properties in the mesoscale deformation mechanisms of collagen fibrils.

PubMed

Depalle, Baptiste; Qin, Zhao; Shefelbine, Sandra J; Buehler, Markus J

2015-12-01

Collagen is a ubiquitous protein with remarkable mechanical properties. It is highly elastic, shows large fracture strength and enables substantial energy dissipation during deformation. Most of the connective tissue in humans consists of collagen fibrils composed of a staggered array of tropocollagen molecules, which are connected by intermolecular cross-links. In this study, we report a three-dimensional coarse-grained model of collagen and analyze the influence of enzymatic cross-links on the mechanics of collagen fibrils. Two representatives immature and mature cross-links are implemented in the mesoscale model using a bottom-up approach. By varying the number, type and mechanical properties of cross-links in the fibrils and performing tensile test on the models, we systematically investigate the deformation mechanisms of cross-linked collagen fibrils. We find that cross-linked fibrils exhibit a three phase behavior, which agrees closer with experimental results than what was obtained using previous models. The fibril mechanical response is characterized by: (i) an initial elastic deformation corresponding to the collagen molecule uncoiling, (ii) a linear regime dominated by molecule sliding and (iii) the second stiffer elastic regime related to the stretching of the backbone of the tropocollagen molecules until the fibril ruptures. Our results suggest that both cross-link density and type dictate the stiffness of large deformation regime by increasing the number of interconnected molecules while cross-links mechanical properties determine the failure strain and strength of the fibril. These findings reveal that cross-links play an essential role in creating an interconnected fibrillar material of tunable toughness and strength. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Preliminary Characterization of Genipin-Cross-Linked Silk Sericin/Poly(vinyl alcohol) Films as Two-Dimensional Wound Dressings for the Healing of Superficial Wounds

PubMed Central

Siritientong, Tippawan; Ratanavaraporn, Juthamas; Srichana, Teerapol; Aramwit, Pornanong

2013-01-01

The genipin-cross-linked silk sericin/poly(vinyl alcohol) (PVA) films were developed aiming to be applied as two-dimensional wound dressings for the treatment of superficial wounds. The effects of genipin cross-linking concentration on the physical and biological properties of the films were investigated. The genipin-cross-linked silk sericin/PVA films showed the increased surface density, tensile strength, and percentage of elongation, but decreased percentage of light transmission, water vapor transmission rate, and water swelling, compared to the non-cross-linked films. This explained that the cross-linking bonds between genipin and silk sericin would reduce the mobility of molecular chains within the films, resulting in the more rigid molecular structure. Silk sericin was released from the genipin-cross-linked films in a sustained manner. In addition, either L929 mouse fibroblast or HaCat keratinocyte cells showed high percentage of viability when cultured on the silk sericin/PVA films cross-linked with 0.075 and 0.1% w/v genipin. The in vivo safety test performed according to ISO 10993-6 confirmed that the genipin-cross-linked silk sericin/PVA films were safe for the medical usages. The efficacy of the films for the treatment of superficial skin wounds will be further investigated in vivo and clinically. The genipin-cross-linked silk sericin/PVA films would be promising choices of two-dimensional wound dressings for the treatment of superficial wounds. PMID:24106722

Preliminary characterization of genipin-cross-linked silk sericin/poly(vinyl alcohol) films as two-dimensional wound dressings for the healing of superficial wounds.

PubMed

Siritientong, Tippawan; Ratanavaraporn, Juthamas; Srichana, Teerapol; Aramwit, Pornanong

2013-01-01

The genipin-cross-linked silk sericin/poly(vinyl alcohol) (PVA) films were developed aiming to be applied as two-dimensional wound dressings for the treatment of superficial wounds. The effects of genipin cross-linking concentration on the physical and biological properties of the films were investigated. The genipin-cross-linked silk sericin/PVA films showed the increased surface density, tensile strength, and percentage of elongation, but decreased percentage of light transmission, water vapor transmission rate, and water swelling, compared to the non-cross-linked films. This explained that the cross-linking bonds between genipin and silk sericin would reduce the mobility of molecular chains within the films, resulting in the more rigid molecular structure. Silk sericin was released from the genipin-cross-linked films in a sustained manner. In addition, either L929 mouse fibroblast or HaCat keratinocyte cells showed high percentage of viability when cultured on the silk sericin/PVA films cross-linked with 0.075 and 0.1% w/v genipin. The in vivo safety test performed according to ISO 10993-6 confirmed that the genipin-cross-linked silk sericin/PVA films were safe for the medical usages. The efficacy of the films for the treatment of superficial skin wounds will be further investigated in vivo and clinically. The genipin-cross-linked silk sericin/PVA films would be promising choices of two-dimensional wound dressings for the treatment of superficial wounds.

Improving Website Hyperlink Structure Using Server Logs

PubMed Central

Paranjape, Ashwin; West, Robert; Zia, Leila; Leskovec, Jure

2016-01-01

Good websites should be easy to navigate via hyperlinks, yet maintaining a high-quality link structure is difficult. Identifying pairs of pages that should be linked may be hard for human editors, especially if the site is large and changes frequently. Further, given a set of useful link candidates, the task of incorporating them into the site can be expensive, since it typically involves humans editing pages. In the light of these challenges, it is desirable to develop data-driven methods for automating the link placement task. Here we develop an approach for automatically finding useful hyperlinks to add to a website. We show that passively collected server logs, beyond telling us which existing links are useful, also contain implicit signals indicating which nonexistent links would be useful if they were to be introduced. We leverage these signals to model the future usefulness of yet nonexistent links. Based on our model, we define the problem of link placement under budget constraints and propose an efficient algorithm for solving it. We demonstrate the effectiveness of our approach by evaluating it on Wikipedia, a large website for which we have access to both server logs (used for finding useful new links) and the complete revision history (containing a ground truth of new links). As our method is based exclusively on standard server logs, it may also be applied to any other website, as we show with the example of the biomedical research site Simtk. PMID:28345077

Adaptive consensus of scale-free multi-agent system by randomly selecting links

NASA Astrophysics Data System (ADS)

Mou, Jinping; Ge, Huafeng

2016-06-01

This paper investigates an adaptive consensus problem for distributed scale-free multi-agent systems (SFMASs) by randomly selecting links, where the degree of each node follows a power-law distribution. The randomly selecting links are based on the assumption that every agent decides to select links among its neighbours according to the received data with a certain probability. Accordingly, a novel consensus protocol with the range of the received data is developed, and each node updates its state according to the protocol. By the iterative method and Cauchy inequality, the theoretical analysis shows that all errors among agents converge to zero, and in the meanwhile, several criteria of consensus are obtained. One numerical example shows the reliability of the proposed methods.

Poecilia picta, a Close Relative to the Guppy, Exhibits Red Male Coloration Polymorphism: A System for Phylogenetic Comparisons

PubMed Central

Lindholm, Anna K.; Sandkam, Ben; Pohl, Kristina; Breden, Felix

2015-01-01

Studies on the evolution of female preference and male color polymorphism frequently focus on single species since traits and preferences are thought to co-evolve. The guppy, Poecilia reticulata, has long been a premier model for such studies because female preferences and orange coloration are well known to covary, especially in upstream/downstream pairs of populations. However, focused single species studies lack the explanatory power of the comparative method, which requires detailed knowledge of multiple species with known evolutionary relationships. Here we describe a red color polymorphism in Poecilia picta, a close relative to guppies. We show that this polymorphism is restricted to males and is maintained in natural populations of mainland South America. Using tests of female preference we show female P. picta are not more attracted to red males, despite preferences for red/orange in closely related species, such as P. reticulata and P. parae. Male color patterns in these closely related species are different from P. picta in that they occur in discrete patches and are frequently Y chromosome-linked. P. reticulata have an almost infinite number of male patterns, while P. parae males occur in discrete morphs. We show the red male polymorphism in P. picta extends continuously throughout the body and is not a Y-linked trait despite the theoretical prediction that sexually-selected characters should often be linked to the heterogametic sex chromosome. The presence/absence of red male coloration of P. picta described here makes this an ideal system for phylogenetic comparisons that could reveal the evolutionary forces maintaining mate choice and color polymorphisms in this speciose group. PMID:26529081

Preparation of Nanocellulose Reinforced Chitosan Films, Cross-Linked by Adipic Acid

PubMed Central

Falamarzpour, Pouria; Behzad, Tayebeh; Zamani, Akram

2017-01-01

Adipic acid, an abundant and nontoxic compound, was used to dissolve and cross-link chitosan. After the preparation of chitosan films through casting technique, the in situ amidation reaction was performed at 80–100 °C as verified by Fourier transform infrared (FT-IR). The reaction was accompanied by the release of water which was employed to investigate the reaction kinetics. Accordingly, the reaction rate followed the first-order model and Arrhenius equation, and the activation energy was calculated to be 18 kJ/mol. Furthermore, the mechanical properties of the chitosan films were comprehensively studied. First, optimal curing conditions (84 °C, 93 min) were introduced through a central composite design. In order to evaluate the effects of adipic acid, the mechanical properties of physically cross-linked (uncured), chemically cross-linked (cured), and uncross-linked (prepared by acetic acid) films were compared. The use of adipic acid improved the tensile strength of uncured and chemically cross-linked films more than 60% and 113%, respectively. Finally, the effect of cellulose nanofibrils (CNFs) on the mechanical performance of cured films, in the presence of glycerol as a plasticizer, was investigated. The plasticized chitosan films reinforced by 5 wt % CNFs showed superior properties as a promising material for the development of chitosan-based biomaterials. PMID:28208822

Preparation of Nanocellulose Reinforced Chitosan Films, Cross-Linked by Adipic Acid.

PubMed

Falamarzpour, Pouria; Behzad, Tayebeh; Zamani, Akram

2017-02-13

Adipic acid, an abundant and nontoxic compound, was used to dissolve and cross-link chitosan. After the preparation of chitosan films through casting technique, the in situ amidation reaction was performed at 80-100 °C as verified by Fourier transform infrared (FT-IR). The reaction was accompanied by the release of water which was employed to investigate the reaction kinetics. Accordingly, the reaction rate followed the first-order model and Arrhenius equation, and the activation energy was calculated to be 18 kJ/mol. Furthermore, the mechanical properties of the chitosan films were comprehensively studied. First, optimal curing conditions (84 °C, 93 min) were introduced through a central composite design. In order to evaluate the effects of adipic acid, the mechanical properties of physically cross-linked (uncured), chemically cross-linked (cured), and uncross-linked (prepared by acetic acid) films were compared. The use of adipic acid improved the tensile strength of uncured and chemically cross-linked films more than 60% and 113%, respectively. Finally, the effect of cellulose nanofibrils (CNFs) on the mechanical performance of cured films, in the presence of glycerol as a plasticizer, was investigated. The plasticized chitosan films reinforced by 5 wt % CNFs showed superior properties as a promising material for the development of chitosan-based biomaterials.

Amide Link Scission in the Polyamide Active Layers of Thin-Film Composite Membranes upon Exposure to Free Chlorine: Kinetics and Mechanisms.

PubMed

Powell, Joshua; Luh, Jeanne; Coronell, Orlando

2015-10-20

The volume-averaged amide link scission in the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine was quantified at a variety of free chlorine exposure times, concentrations, and pH and rinsing conditions. The results showed that (i) hydroxyl ions are needed for scission to occur, (ii) hydroxide-induced amide link scission is a strong function of exposure to hypochlorous acid, (iii) the ratio between amide links broken and chlorine atoms taken up increased with the chlorination pH and reached a maximum of ∼25%, (iv) polyamide disintegration occurs when high free chlorine concentrations, alkaline conditions, and high exposure times are combined, (v) amide link scission promotes further chlorine uptake, and (vi) scission at the membrane surface is unrepresentative of volume-averaged scission in the active layer. Our observations are consistent with previously proposed mechanisms describing amide link scission as a result of the hydrolysis of the N-chlorinated amidic N-C bond due to nucleophilic attack by hydroxyl ions. This study increases the understanding of the physicochemical changes that could occur for membranes in treatment plants using chlorine as an upstream disinfectant and the extent and rate at which those changes would occur.

What do computer scientists tweet? Analyzing the link-sharing practice on Twitter.

PubMed

Schmitt, Marco; Jäschke, Robert

2017-01-01

Twitter communication has permeated every sphere of society. To highlight and share small pieces of information with possibly vast audiences or small circles of the interested has some value in almost any aspect of social life. But what is the value exactly for a scientific field? We perform a comprehensive study of computer scientists using Twitter and their tweeting behavior concerning the sharing of web links. Discerning the domains, hosts and individual web pages being tweeted and the differences between computer scientists and a Twitter sample enables us to look in depth at the Twitter-based information sharing practices of a scientific community. Additionally, we aim at providing a deeper understanding of the role and impact of altmetrics in computer science and give a glance at the publications mentioned on Twitter that are most relevant for the computer science community. Our results show a link sharing culture that concentrates more heavily on public and professional quality information than the Twitter sample does. The results also show a broad variety in linked sources and especially in linked publications with some publications clearly related to community-specific interests of computer scientists, while others with a strong relation to attention mechanisms in social media. This refers to the observation that Twitter is a hybrid form of social media between an information service and a social network service. Overall the computer scientists' style of usage seems to be more on the information-oriented side and to some degree also on professional usage. Therefore, altmetrics are of considerable use in analyzing computer science.

Eco-friendly and biocompatible cross-linked carboxymethylcellulose hydrogels as adsorbents for the removal of organic dye pollutants for environmental applications.

PubMed

Capanema, Nádia S V; Mansur, Alexandra A P; Mansur, Herman S; de Jesus, Anderson C; Carvalho, Sandhra M; Chagas, Poliane; de Oliveira, Luiz C

2017-08-28

In this study, new eco-friendly hydrogel adsorbents were synthesized based on carboxymethylcellulose (CMC, degree of substitution [DS] = 0.7) chemically cross-linked with citric acid (CA) using a green process in aqueous solution and applied for the adsorption of methylene blue (MB). Spectroscopic analyses demonstrated the mechanism of cross-linking through the reaction of hydroxyl functional groups from CMC with CA. These CMC hydrogels showed very distinct morphological features dependent on the extension of cross-linking and their nanomechanical properties were drastically increased by approximately 300% after cross-linking with 20% CA (e.g. elastic moduli from 80 ± 15 to 270 ± 50 MPa). Moreover, they were biocompatible using an in vitro cell viability assay in contact with human osteosarcoma-derived cells (SAOS) for 24 h. These CMC-based hydrogels exhibited adsorption efficiency above 90% (24 h) and maximum removal capacity of MB from 5 to 25 mg g -1 depending on the dye concentration (from 100 to 500 mg L -1 ), which was used as the model cationic organic pollutant. The adsorption of process of MB was well-fit to the pseudo-second-order kinetics model. The desorption of MB by immersion in KCl solution (3 mol L -1 , 24 h) showed a typical recovery efficiency of over 60% with conceivable reuse of these CMC-based hydrogels. Conversely, CMC hydrogels repelled methyl orange dye used as model anionic pollutant, proving the mechanism of adsorption by the formation of charged polyelectrolyte/dye complexes.

What do computer scientists tweet? Analyzing the link-sharing practice on Twitter

PubMed Central

Schmitt, Marco

2017-01-01

Twitter communication has permeated every sphere of society. To highlight and share small pieces of information with possibly vast audiences or small circles of the interested has some value in almost any aspect of social life. But what is the value exactly for a scientific field? We perform a comprehensive study of computer scientists using Twitter and their tweeting behavior concerning the sharing of web links. Discerning the domains, hosts and individual web pages being tweeted and the differences between computer scientists and a Twitter sample enables us to look in depth at the Twitter-based information sharing practices of a scientific community. Additionally, we aim at providing a deeper understanding of the role and impact of altmetrics in computer science and give a glance at the publications mentioned on Twitter that are most relevant for the computer science community. Our results show a link sharing culture that concentrates more heavily on public and professional quality information than the Twitter sample does. The results also show a broad variety in linked sources and especially in linked publications with some publications clearly related to community-specific interests of computer scientists, while others with a strong relation to attention mechanisms in social media. This refers to the observation that Twitter is a hybrid form of social media between an information service and a social network service. Overall the computer scientists’ style of usage seems to be more on the information-oriented side and to some degree also on professional usage. Therefore, altmetrics are of considerable use in analyzing computer science. PMID:28636619

Roads at risk - the impact of debris flows on road network reliability and vulnerability in southern Norway

NASA Astrophysics Data System (ADS)

Meyer, Nele Kristin; Schwanghart, Wolfgang; Korup, Oliver

2014-05-01

Norwegian's road network is frequently affected by debris flows. Both damage repair and traffic interruption generate high economic losses and necessitate a rigorous assessment of where losses are expected to be high and where preventive measures should be focused on. In recent studies, we have developed susceptibility and trigger probability maps that serve as input into a hazard calculation at the scale of first-order watersheds. Here we combine these results with graph theory to assess the impact of debris flows on the road network of southern Norway. Susceptibility and trigger probability are aggregated for individual road sections to form a reliability index that relates to the failure probability of a link that connects two network vertices, e.g., road junctions. We define link vulnerability as a function of traffic volume and additional link failure distance. Additional link failure distance is the extra length of the alternative path connecting the two associated link vertices in case the network link fails and is calculated by a shortest-path algorithm. The product of network reliability and vulnerability indices represent the risk index. High risk indices identify critical links for the Norwegian road network and are investigated in more detail. Scenarios demonstrating the impact of single or multiple debris flow events are run for the most important routes between seven large cities in southern Norway. First results show that the reliability of the road network is lowest in the central and north-western part of the study area. Road network vulnerability is highest in the mountainous regions in central southern Norway where the road density is low and in the vicinity of cities where the traffic volume is large. The scenarios indicate that city connections that have their shortest path via routes crossing the central part of the study area have the highest risk of route failure.

LinkImputeR: user-guided genotype calling and imputation for non-model organisms.

PubMed

Money, Daniel; Migicovsky, Zoë; Gardner, Kyle; Myles, Sean

2017-07-10

Genomic studies such as genome-wide association and genomic selection require genome-wide genotype data. All existing technologies used to create these data result in missing genotypes, which are often then inferred using genotype imputation software. However, existing imputation methods most often make use only of genotypes that are successfully inferred after having passed a certain read depth threshold. Because of this, any read information for genotypes that did not pass the threshold, and were thus set to missing, is ignored. Most genomic studies also choose read depth thresholds and quality filters without investigating their effects on the size and quality of the resulting genotype data. Moreover, almost all genotype imputation methods require ordered markers and are therefore of limited utility in non-model organisms. Here we introduce LinkImputeR, a software program that exploits the read count information that is normally ignored, and makes use of all available DNA sequence information for the purposes of genotype calling and imputation. It is specifically designed for non-model organisms since it requires neither ordered markers nor a reference panel of genotypes. Using next-generation DNA sequence (NGS) data from apple, cannabis and grape, we quantify the effect of varying read count and missingness thresholds on the quantity and quality of genotypes generated from LinkImputeR. We demonstrate that LinkImputeR can increase the number of genotype calls by more than an order of magnitude, can improve genotyping accuracy by several percent and can thus improve the power of downstream analyses. Moreover, we show that the effects of quality and read depth filters can differ substantially between data sets and should therefore be investigated on a per-study basis. By exploiting DNA sequence data that is normally ignored during genotype calling and imputation, LinkImputeR can significantly improve both the quantity and quality of genotype data generated from NGS technologies. It enables the user to quickly and easily examine the effects of varying thresholds and filters on the number and quality of the resulting genotype calls. In this manner, users can decide on thresholds that are most suitable for their purposes. We show that LinkImputeR can significantly augment the value and utility of NGS data sets, especially in non-model organisms with poor genomic resources.

The ChEMBL database as linked open data

PubMed Central

2013-01-01

Background Making data available as Linked Data using Resource Description Framework (RDF) promotes integration with other web resources. RDF documents can natively link to related data, and others can link back using Uniform Resource Identifiers (URIs). RDF makes the data machine-readable and uses extensible vocabularies for additional information, making it easier to scale up inference and data analysis. Results This paper describes recent developments in an ongoing project converting data from the ChEMBL database into RDF triples. Relative to earlier versions, this updated version of ChEMBL-RDF uses recently introduced ontologies, including CHEMINF and CiTO; exposes more information from the database; and is now available as dereferencable, linked data. To demonstrate these new features, we present novel use cases showing further integration with other web resources, including Bio2RDF, Chem2Bio2RDF, and ChemSpider, and showing the use of standard ontologies for querying. Conclusions We have illustrated the advantages of using open standards and ontologies to link the ChEMBL database to other databases. Using those links and the knowledge encoded in standards and ontologies, the ChEMBL-RDF resource creates a foundation for integrated semantic web cheminformatics applications, such as the presented decision support. PMID:23657106

Imprinted and X-linked non-coding RNAs as potential regulators of human placental function

PubMed Central

Buckberry, Sam; Bianco-Miotto, Tina; Roberts, Claire T

2014-01-01

Pregnancy outcome is inextricably linked to placental development, which is strictly controlled temporally and spatially through mechanisms that are only partially understood. However, increasing evidence suggests non-coding RNAs (ncRNAs) direct and regulate a considerable number of biological processes and therefore may constitute a previously hidden layer of regulatory information in the placenta. Many ncRNAs, including both microRNAs and long non-coding transcripts, show almost exclusive or predominant expression in the placenta compared with other somatic tissues and display altered expression patterns in placentas from complicated pregnancies. In this review, we explore the results of recent genome-scale and single gene expression studies using human placental tissue, but include studies in the mouse where human data are lacking. Our review focuses on the ncRNAs epigenetically regulated through genomic imprinting or X-chromosome inactivation and includes recent evidence surrounding the H19 lincRNA, the imprinted C19MC cluster microRNAs, and X-linked miRNAs associated with pregnancy complications. PMID:24081302

Experimental Myocardial Infarction Upregulates Circulating Fibroblast Growth Factor-23.

PubMed

Andrukhova, Olena; Slavic, Svetlana; Odörfer, Kathrin I; Erben, Reinhold G

2015-10-01

Myocardial infarction (MI) is a major cause of death worldwide. Epidemiological studies have linked vitamin D deficiency to MI incidence. Because fibroblast growth factor-23 (FGF23) is a master regulator of vitamin D hormone production and has been shown to be associated with cardiac hypertrophy per se, we explored the hypothesis that FGF23 may be a previously unrecognized pathophysiological factor causally linked to progression of cardiac dysfunction post-MI. Here, we show that circulating intact Fgf23 was profoundly elevated, whereas serum vitamin D hormone levels were suppressed, after induction of experimental MI in rat and mouse models, independent of changes in serum soluble Klotho or serum parathyroid hormone. Both skeletal and cardiac expression of Fgf23 was increased after MI. Although the molecular link between the cardiac lesion and circulating Fgf23 concentrations remains to be identified, our study has uncovered a novel heart-bone-kidney axis that may have important clinical implications and may inaugurate the new field of cardio-osteology. © 2015 American Society for Bone and Mineral Research.

Prospective associations between loneliness and emotional intelligence.

PubMed

Wols, A; Scholte, R H J; Qualter, P

2015-02-01

Loneliness has been linked cross-sectionally to emotional skill deficits (e.g., Zysberg, 2012), but missing from the literature is a longitudinal examination of these relationships. The present study fills that gap by examining the prospective relationships between loneliness and emotional functioning in young adolescents in England. One hundred and ninety-six adolescents aged 11-13 years (90 females) took part in the study and completed the youth version of the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT-YV) and the peer-related subscale of the Loneliness and Aloneness Scale for Children and Adolescents (LACA) at two time points, which were 10 months apart. Prospective associations were obtained for male and female adolescents separately using cross-lagged statistical techniques. Our results showed prospective links between understanding and managing emotions and loneliness for both females and males. Perceiving and using emotions were prospectively linked to loneliness in males only. Possible explanations and directions for future research are discussed. Copyright © 2014 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Discrimination, Harassment, Abuse and Bullying in the Workplace: Contribution of Workplace Injustice to Occupational Health Disparities

PubMed Central

Okechukwu, Cassandra A.; Souza, Kerry; Davis, Kelly D.; de Castro, A. Butch

2013-01-01

This paper synthesizes research on the contribution of workplace injustices – discrimination, harassment, abuse and bullying – to occupational health disparities. A conceptual framework is presented to illustrate the pathways through which injustices at the interpersonal and institutional level lead to differential risk of vulnerable workers to adverse occupational health outcomes. Members of demographic minority groups are more likely to be victims of workplace injustice and suffer more adverse outcomes when exposed to workplace injustice compared to demographic majority groups. A growing body of research links workplace injustice to poor psychological and physical health, and a smaller body of evidence links workplace injustice to unhealthy behaviors. Although not as well studied, studies also show that workplace injustice can influence workers’ health through effects on workers’ family life and job-related outcomes. Lastly, this paper discusses methodological limitations in research linking injustices and occupational health disparities and makes recommendations to improve the state of research. PMID:23813664

The centrality of fear extinction in linking risk factors to PTSD: A narrative review.

PubMed

Zuj, Daniel V; Palmer, Matthew A; Lommen, Miriam J J; Felmingham, Kim L

2016-10-01

Recent prospective studies in emergency services have identified impaired fear extinction learning and memory to be a significant predictor of Posttraumatic Stress Disorder (PTSD), complementing a wealth of cross-sectional evidence of extinction deficits associated with the disorder. Additional fields of research show specific risk factors and biomarkers of the disorder, including candidate genotypes, stress and sex hormones, cognitive factors, and sleep disturbances. Studies in mostly nonclinical populations also reveal that the aforementioned factors are involved in fear extinction learning and memory. Here, we provide a comprehensive narrative review of the literature linking PTSD to these risk factors, and linking these risk factors to impaired fear extinction. On balance, the evidence suggests that fear extinction may play a role in the relationship between risk factors and PTSD. Should this notion hold true, this review carries important implications for the improvement of exposure-based treatments, as well as strategies for the implementation of treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Controlling Hysteresis in Superconducting Weak Links and μ-Superconducting Quantum Interference Devices

NASA Astrophysics Data System (ADS)

Kumar, Nikhil; Winkelmann, C. B.; Biswas, Sourav; Courtois, H.; Gupta, Anjan K.

We have fabricated and studied the current-voltage characteristics of a number of niobium film based weak-link devices and μ-SQUIDs showing a critical current and two re-trapping currents. We have proposed a new understanding for the re-trapping currents in terms of thermal instabilities in different portions of the device. We also find that the superconducting proximity effect and the phase-slip processes play an important role in dictating the temperature dependence of the critical current in the non-hysteretic regime. The proximity effect helps in widening the temperature range of hysteresis-free characteristics. Finally we demonstrate control on temperature-range with hysteresis-free characteristics in two ways: 1) By using a parallel shunt resistor in close vicinity of the device, and 2) by reducing the weak-link width. Thus we get non-hysteretic behavior down to 1.3 K temperature in some of the studied devices. We acknowledge the financial support from CSIR, India as well as CNRS-Institute Neel, Grenoble, France.

On the Difference Between Additive and Subtractive QM/MM Calculations

PubMed Central

Cao, Lili; Ryde, Ulf

2018-01-01

The combined quantum mechanical (QM) and molecular mechanical (MM) approach (QM/MM) is a popular method to study reactions in biochemical macromolecules. Even if the general procedure of using QM for a small, but interesting part of the system and MM for the rest is common to all approaches, the details of the implementations vary extensively, especially the treatment of the interface between the two systems. For example, QM/MM can use either additive or subtractive schemes, of which the former is often said to be preferable, although the two schemes are often mixed up with mechanical and electrostatic embedding. In this article, we clarify the similarities and differences of the two approaches. We show that inherently, the two approaches should be identical and in practice require the same sets of parameters. However, the subtractive scheme provides an opportunity to correct errors introduced by the truncation of the QM system, i.e., the link atoms, but such corrections require additional MM parameters for the QM system. We describe and test three types of link-atom correction, viz. for van der Waals, electrostatic, and bonded interactions. The calculations show that electrostatic and bonded link-atom corrections often give rise to problems in the geometries and energies. The van der Waals link-atom corrections are quite small and give results similar to a pure additive QM/MM scheme. Therefore, both approaches can be recommended. PMID:29666794

X-linked cataract and Nance-Horan syndrome are allelic disorders.

PubMed

Coccia, Margherita; Brooks, Simon P; Webb, Tom R; Christodoulou, Katja; Wozniak, Izabella O; Murday, Victoria; Balicki, Martha; Yee, Harris A; Wangensteen, Teresia; Riise, Ruth; Saggar, Anand K; Park, Soo-Mi; Kanuga, Naheed; Francis, Peter J; Maher, Eamonn R; Moore, Anthony T; Russell-Eggitt, Isabelle M; Hardcastle, Alison J

2009-07-15

Nance-Horan syndrome (NHS) is an X-linked developmental disorder characterized by congenital cataract, dental anomalies, facial dysmorphism and, in some cases, mental retardation. Protein truncation mutations in a novel gene (NHS) have been identified in patients with this syndrome. We previously mapped X-linked congenital cataract (CXN) in one family to an interval on chromosome Xp22.13 which encompasses the NHS locus; however, no mutations were identified in the NHS gene. In this study, we show that NHS and X-linked cataract are allelic diseases. Two CXN families, which were negative for mutations in the NHS gene, were further analysed using array comparative genomic hybridization. CXN was found to be caused by novel copy number variations: a complex duplication-triplication re-arrangement and an intragenic deletion, predicted to result in altered transcriptional regulation of the NHS gene. Furthermore, we also describe the clinical and molecular analysis of seven families diagnosed with NHS, identifying four novel protein truncation mutations and a novel large deletion encompassing the majority of the NHS gene, all leading to no functional protein. We therefore show that different mechanisms, aberrant transcription of the NHS gene or no functional NHS protein, lead to different diseases. Our data highlight the importance of copy number variation and non-recurrent re-arrangements leading to different severity of disease and describe the potential mechanisms involved.

X-linked cataract and Nance-Horan syndrome are allelic disorders

PubMed Central

Coccia, Margherita; Brooks, Simon P.; Webb, Tom R.; Christodoulou, Katja; Wozniak, Izabella O.; Murday, Victoria; Balicki, Martha; Yee, Harris A.; Wangensteen, Teresia; Riise, Ruth; Saggar, Anand K.; Park, Soo-Mi; Kanuga, Naheed; Francis, Peter J.; Maher, Eamonn R.; Moore, Anthony T.; Russell-Eggitt, Isabelle M.; Hardcastle, Alison J.

2009-01-01

Nance-Horan syndrome (NHS) is an X-linked developmental disorder characterized by congenital cataract, dental anomalies, facial dysmorphism and, in some cases, mental retardation. Protein truncation mutations in a novel gene (NHS) have been identified in patients with this syndrome. We previously mapped X-linked congenital cataract (CXN) in one family to an interval on chromosome Xp22.13 which encompasses the NHS locus; however, no mutations were identified in the NHS gene. In this study, we show that NHS and X-linked cataract are allelic diseases. Two CXN families, which were negative for mutations in the NHS gene, were further analysed using array comparative genomic hybridization. CXN was found to be caused by novel copy number variations: a complex duplication–triplication re-arrangement and an intragenic deletion, predicted to result in altered transcriptional regulation of the NHS gene. Furthermore, we also describe the clinical and molecular analysis of seven families diagnosed with NHS, identifying four novel protein truncation mutations and a novel large deletion encompassing the majority of the NHS gene, all leading to no functional protein. We therefore show that different mechanisms, aberrant transcription of the NHS gene or no functional NHS protein, lead to different diseases. Our data highlight the importance of copy number variation and non-recurrent re-arrangements leading to different severity of disease and describe the potential mechanisms involved. PMID:19414485

On the difference between additive and subtractive QM/MM calculations

NASA Astrophysics Data System (ADS)

Cao, Lili; Ryde, Ulf

2018-04-01

The combined quantum mechanical (QM) and molecular mechanical (MM) approach (QM/MM) is a popular method to study reactions in biochemical macromolecules. Even if the general procedure of using QM for a small, but interesting part of the system and MM for the rest is common to all approaches, the details of the implementations vary extensively, especially the treatment of the interface between the two systems. For example, QM/MM can use either additive or subtractive schemes, of which the former is often said to be preferable, although the two schemes are often mixed up with mechanical and electrostatic embedding. In this article, we clarify the similarities and differences of the two approaches. We show that inherently, the two approaches should be identical and in practice require the same sets of parameters. However, the subtractive scheme provides an opportunity to correct errors introduced by the truncation of the QM system, i.e. the link atoms, but such corrections require additional MM parameters for the QM system. We describe and test three types of link-atom correction, viz. for van der Waals, electrostatic and bonded interactions. The calculations show that electrostatic and bonded link-atom corrections often give rise to problems in the geometries and energies. The van der Waals link-atom corrections are quite small and give results similar to a pure additive QM/MM scheme. Therefore, both approaches can be recommended.

A Historical Study to Understand Students' Current Difficulties about RMS Values

ERIC Educational Resources Information Center

Khantine-Langlois, Françoise; Munier, Valérie

2016-01-01

Several studies show that students experience more and more difficulties managing the measurements of electrical values in alternating current and that they have trouble making links between theory and practice. They find it difficult to give meaning to root mean square (RMS; or effective) values, which are not understood as average values and are…

Pathways from Adolescent Deliberate Self-Poisoning to Early Adult Outcomes: A Six-Year Follow-Up

ERIC Educational Resources Information Center

Aglan, Azza; Kerfoot, Michael; Pickles, Andrew

2008-01-01

Background: Prospective studies show that the adult outcomes of adolescents who deliberately harm themselves are marked by high rates of adversity and psychiatric disorders. The goal of this study was to identify pathways linking childhood risk factors to early adult outcomes of suicidal adolescents. Methods: A clinical sample of 158 adolescents…

Relationships between Family Connectedness and Body Satisfaction: A Longitudinal Study of Adolescent Girls and Boys

ERIC Educational Resources Information Center

Crespo, Carla; Kielpikowski, Magdalena; Jose, Paul; Pryor, Jan

2010-01-01

The present study examined the longitudinal links between perceptions of family connectedness and body satisfaction in 1,774 (52% female) adolescents. Participants (10-15 years of age at Time 1) completed self-report measures at three measurement occasions separated by 1 year each. Mean group difference results showed that both body satisfaction…

A Study in Kuwait of Health Risks Associated with Using Cell Phones

ERIC Educational Resources Information Center

Al-Khamees, Nedaa

2007-01-01

Previous studies have suggested a link between cell phone use and various symptoms. Analysis of 3,274 completed questionnaires from throughout Kuwait show a significant effect of exposure to cell phones for burning sensation on the ear, temporal pain, pain in the back of the head, auricular pain, noises in the ear, ear numbness, heartbeat…

N(4)C-ethyl-N(4)C cross-linked DNA: synthesis and characterization of duplexes with interstrand cross-links of different orientations.

PubMed

Noronha, Anne M; Noll, David M; Wilds, Christopher J; Miller, Paul S

2002-01-22

The preparation and physical properties of short DNA duplexes that contain a N(4)C-ethyl-N(4)C interstrand cross-link are described. Duplexes that contain an interstrand cross-link between mismatched C-C residues and duplexes in which the C residues of a -CG- or -GC- step are linked to give "staggered" interstrand cross-links were prepared using a novel N(4)C-ethyl-N(4)C phosphoramidite reagent. Duplexes with the C-C mismatch cross-link have UV thermal transition temperatures that are 25 degrees C higher than the melting temperatures of control duplexes in which the cross-link is replaced with a G-C base pair. It appears that this cross-link stabilizes adjacent base pairs and does not perturb the structure of the helix, a conclusion that is supported by the CD spectrum of this duplex and by molecular models. An even higher level of stabilization, 49 degrees C, is seen with the duplex that contains a -CG- staggered cross-link. Molecular models suggest that this cross-link may induce propeller twisting in the cross-linked base pairs, and the CD spectrum of this duplex exhibits an unusual negative band at 298 nm, although the remainder of the spectrum is similar to that of B-form DNA. Mismatched C-C or -CG- staggered cross-linked duplexes that have complementary overhanging ends can undergo self-ligation catalyzed by T4 DNA ligase. Analysis of the ligated oligomers by nondenaturing polyacrylamide gel electrophoresis shows that the resulting oligomers migrate in a manner similar to that of a mixture of non-cross-linked control oligomers and suggests that these cross-links do not result in significant bending of the helix. However, the orientation of the staggered cross-link can have a significant effect on the structure and stability of the cross-linked duplex. Thus, the thermal stability of the duplex that contains a -GC- staggered cross-link is 10 degrees C lower than the melting temperature of the control, non-cross-linked duplex. Unlike the -CG- staggered cross-link, in which the cross-linked base pairs can still maintain hydrogen bond contacts, molecular models suggest that formation of the -GC- staggered cross-link disrupts hydrogen bonding and may also perturb adjacent base pairs leading to an overall reduction in helix stability. Duplexes with specifically positioned and oriented cross-links can be used as substrates to study DNA repair mechanisms.

Ubiquitousness of link-density and link-pattern communities in real-world networks

NASA Astrophysics Data System (ADS)

Šubelj, L.; Bajec, M.

2012-01-01

Community structure appears to be an intrinsic property of many complex real-world networks. However, recent work shows that real-world networks reveal even more sophisticated modules than classical cohesive (link-density) communities. In particular, networks can also be naturally partitioned according to similar patterns of connectedness among the nodes, revealing link-pattern communities. We here propose a propagation based algorithm that can extract both link-density and link-pattern communities, without any prior knowledge of the true structure. The algorithm was first validated on different classes of synthetic benchmark networks with community structure, and also on random networks. We have further applied the algorithm to different social, information, technological and biological networks, where it indeed reveals meaningful (composites of) link-density and link-pattern communities. The results thus seem to imply that, similarly as link-density counterparts, link-pattern communities appear ubiquitous in nature and design.

Identification of an O-linked repetitive glycan chain of the polar flagellum flagellin of Azospirillum brasilense Sp7.

PubMed

Belyakov, Alexei Ye; Burygin, Gennady L; Arbatsky, Nikolai P; Shashkov, Alexander S; Selivanov, Nikolai Yu; Matora, Larisa Yu; Knirel, Yuriy A; Shchyogolev, Sergei Yu

2012-11-01

This is the first report to have identified an O-linked repetitive glycan in bacterial flagellin, a structural protein of the flagellum. Studies by sugar analysis, Smith degradation, (1)H and (13)C NMR spectroscopy, and mass spectrometry showed that the glycan chains of the polar flagellum flagellin of the plant-growth-promoting rhizobacterium Azospirillum brasilense Sp7 are represented by a polysaccharide with a molecular mass of 7.7 kDa, which has a branched tetrasaccharide repeating unit of the following structure: Copyright © 2012. Published by Elsevier Ltd.

Parent characteristics linked with daughters' attachment styles.

PubMed

Kilmann, Peter R; Vendemia, Jennifer M C; Parnell, Michele M; Urbaniak, Geoffrey C

2009-01-01

This study investigated links between parent characteristics and daughters' attachment styles for 90 female undergraduates and their married biological parents. Parents with a secure attachment pattern were rated as more accepting, less controlling, more competent, and more consistent in showing love and affection to their daughter in contrast to parents with an insecure attachment pattern. Significant positive associations were found between mothers' fearful attachment scores and the fearful, preoccupied, and dismissive attachment scores of daughters. Daughters of matched secure parents were more likely to report a secure attachment style, while daughters of matched insecure parents were more likely to report an insecure attachment style.

Nutritional influences on epigenetic programming: asthma, allergy, and obesity.

PubMed

Palmer, Debra J; Huang, Rae-Chi; Craig, Jeffrey M; Prescott, Susan L

2014-11-01

Observational studies show consistent links between early-life nutritional exposures as important risk factors for the development of asthma, allergy, and obesity. Reliance on increasing use of dietary supplementation and fortification (eg, with folate) to compensate for increased consumption of processed foods is also influencing immune and metabolic outcomes. Epigenetics is providing substantial advances in understanding how early-life nutritional exposures can effect disease development. This article summarizes current evidence linking the influence of early-life nutritional exposures on epigenetic regulation with a focus on the disease outcomes of asthma, allergy, and obesity. Copyright © 2014 Elsevier Inc. All rights reserved.

[Activity of the sympatho-adrenal system in patients with hysterical psychopathy and psychasthenia].

PubMed

Trunova, M M

1978-01-01

The paper is concerned with studies of the sympathoadrenal system activity by the indices of urine excretion of catecholamine and dofa in patients with hysterical and psychasthenic psychopathy. The disorders inherent in each of the groups are demonstrated. The patients with hysterical psychopathy show an exhaustion of all links in the catecholamine metabolism, while the patients with psychasthenical psychopathy an exhaustion of the noradrenaline link. In attempting to explain the mechanisms of disturbed activity in the sympathoadrenal system in both groups the role of the functional state of nonspecific activizing brain systems was taken into consideration.

Psychoneuroimmunology in Health Education.

ERIC Educational Resources Information Center

Hanson, Carl

1992-01-01

Studies suggest that stress, emotions, personality, and cognition can affect the immune system's response to disease. This paper argues the need for psychoneuroimmunology to be taught in health education courses and provides a brief overview of research showing the link between the mind and the immune system. (GLR)

At-a-Glance: Healthy Sleep

MedlinePlus

... make you irritable and is linked to poor behavior and trouble with relationships, especially among children and teens. People who chronically lack sleep are also more likely to become depressed. Health Sleep also is important for good health. Studies show that not getting enough sleep or getting ...

Tracing the trajectory of skill learning with a very large sample of online game players.

PubMed

Stafford, Tom; Dewar, Michael

2014-02-01

In the present study, we analyzed data from a very large sample (N = 854,064) of players of an online game involving rapid perception, decision making, and motor responding. Use of game data allowed us to connect, for the first time, rich details of training history with measures of performance from participants engaged for a sustained amount of time in effortful practice. We showed that lawful relations exist between practice amount and subsequent performance, and between practice spacing and subsequent performance. Our methodology allowed an in situ confirmation of results long established in the experimental literature on skill acquisition. Additionally, we showed that greater initial variation in performance is linked to higher subsequent performance, a result we link to the exploration/exploitation trade-off from the computational framework of reinforcement learning. We discuss the benefits and opportunities of behavioral data sets with very large sample sizes and suggest that this approach could be particularly fecund for studies of skill acquisition.

Towards producing novel fish gelatin films by combination treatments of ultraviolet radiation and sugars (ribose and lactose) as cross-linking agents.

PubMed

Bhat, Rajeev; Karim, A A

2014-07-01

Developing novel fish gelatin films with better mechanical properties than mammalian gelatin is a challenging but promising endeavor. Studies were undertaken to produce fish gelatin films by combining treatments with different sugars (ribose and lactose) followed 'by' 'and' ultraviolet (UV) radiation, as possible cross-linking agents. Increase in tensile strength and percent elongation at break was recorded, which was more significant in films without sugars that were exposed to UV radiation. Films with added ribose showed decreased solubility after UV treatment and exhibited higher swelling percentage than films with added lactose, which readily dissolved in water. FTIR spectra of all the films showed identical patterns, which indicated no major changes to have occurred in the functional groups as a result of interaction between gelatin, sugars and UV irradiation. The results of this study could be explored for commercial use, depending on industrial needs for either production of edible films or for food packaging purposes.

Evaluating the Link between Self-Esteem and Temperament in Mexican Origin Early Adolescents

PubMed Central

Robins, Richard W.; Donnellan, M. Brent; Widaman, Keith F.; Conger, Rand D.

2009-01-01

The present study examined the relation between self-esteem and temperament in a sample of 646 Mexican-American early adolescents (mean age=10.4). Self-esteem was assessed using child reports on the Self-Description Questionnaire II—Short (SDQII-S; Marsh et al., 2005) and temperament was assessed using child and mother reports on the revised Early Adolescent Temperament Questionnaire (Ellis & Rothbart, 2001). Findings show that: (a) early adolescents with high self-esteem show higher levels of Effortful Control but, contrary to findings in adult samples, do not differ from low self-esteem adolescents in Negative Affectivity; (b) low self-esteem is associated with Depression; and (c) low self-esteem is associated with Aggression. These findings replicated for boys and girls, two measures of self-esteem, and child and mother reports of temperament. The present study contributes to an emerging understanding of the link between self-esteem and temperament, and provides much needed data on the nature of self-esteem in ethnic minority populations. PMID:19740537

Insights into the Mechanism of a Covalently Linked Organic Dye–Cobaloxime Catalyst System for Dye‐Sensitized Solar Fuel Devices

PubMed Central

Pati, Palas Baran; Zhang, Lei; Philippe, Bertrand; Fernández‐Terán, Ricardo; Ahmadi, Sareh; Tian, Lei; Rensmo, Håkan; Hammarström, Leif

2017-01-01

Abstract A covalently linked organic dye–cobaloxime catalyst system based on mesoporous NiO is synthesized by a facile click reaction for mechanistic studies and application in a dye‐sensitized solar fuel device. The system is systematically investigated by photoelectrochemical measurements, density functional theory, time‐resolved fluorescence, transient absorption spectroscopy, and photoelectron spectroscopy. The results show that irradiation of the dye–catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer process to reduce the catalyst. Moreover, the dye adopts different structures with different excited state energies, and excitation energy transfer occurs between neighboring molecules on the semiconductor surface. The photoelectrochemical experiments also show hydrogen production by this system. The axial chloride ligands of the catalyst are released during photocatalysis to create the active sites for proton reduction. A working mechanism of the dye–catalyst system on the photocathode is proposed on the basis of this study. PMID:28338295

Does the taste matter? Taste and medicinal perceptions associated with five selected herbal drugs among three ethnic groups in West Yorkshire, Northern England

PubMed Central

Pieroni, Andrea; Torry, Bren

2007-01-01

In recent years, diverse scholars have addressed the issue of the chemosensory perceptions associated with traditional medicines, nevertheless there is still a distinct lack of studies grounded in the social sciences and conducted from a cross-cultural, comparative perspective. In this urban ethnobotanical field study, 254 informants belonging to the Gujarati, Kashmiri and English ethnic groups and living in Western Yorkshire in Northern England were interviewed about the relationship between taste and medicinal perceptions of five herbal drugs, which were selected during a preliminary study. The herbal drugs included cinnamon (the dried bark of Cinnamomum verum, Lauraceae), mint (the leaves of Mentha spp., Lamiaceae), garlic (the bulbs of Allium sativum, Alliaceae), ginger (the rhizome of Zingiber officinale, Zingiberaceae), and cloves (the dried flower buds of Syzygium aromaticum, Myrtaceae). The main cross-cultural differences in taste perceptions regarded the perception the perception of the spicy taste of ginger, garlic, and cinnamon, of the bitter taste of ginger, the sweet taste of mint, and of the sour taste of garlic. The part of the study of how the five selected herbal drugs are perceived medicinally showed that TK (Traditional Knowledge) is widespread among Kashmiris, but not so prevalent among the Gujarati and especially the English samples. Among Kashmiris, ginger was frequently considered to be helpful for healing infections and muscular-skeletal and digestive disorders, mint was chosen for healing digestive and respiratory troubles, garlic for blood system disorders, and cinnamon was perceived to be efficacious for infectious diseases. Among the Gujarati and Kashmiri groups there was evidence of a strong link between the bitter and spicy tastes of ginger, garlic, cloves, and cinnamon and their perceived medicinal properties, whereas there was a far less obvious link between the sweet taste of mint and cinnamon and their perceived medicinal properties, although the link did exist among some members of the Gujarati group. Data presented in this study show how that links between taste perceptions and medicinal uses of herbal drugs may be understood as bio-cultural phenomena rooted in human physiology, but also constructed through individual experiences and culture, and that these links can therefore be quite different across diverse cultures. PMID:17475019

On the relationship between the Indian summer monsoon rainfall and the EQUINOO in the CFSv2

NASA Astrophysics Data System (ADS)

Vishnu, S.; Francis, P. A.; Ramakrishna, S. S. V. S.; Shenoi, S. S. C.

2018-03-01

Several recent studies have shown that positive (negative) phase of Equatorial Indian Ocean Oscillation (EQUINOO) is favourable (unfavourable) to the Indian summer monsoon. However, many ocean-atmosphere global coupled models, including the state-of-the-art Climate Forecast System (CFS) version 2 have difficulty in reproducing this link realistically. In this study, we analyze the retrospective forecasts by the CFS model for the period 1982-2010 with an objective to identify the reasons behind the failure of the model to simulate the observed links between Indian summer monsoon and EQUINOO. It is found that, in the model hindcasts, the rainfall in the core monsoon region was mainly due to westward propagating synoptic scale systems, that originated from the vicinity of the tropical convergence zone (TCZ). Our analysis shows that unlike in observations, in the CFS, majority of positive (negative) EQUINOO events are associated with El Niño (La Niña) events in the Pacific. In addition to this, there is a strong link between EQUINOO and Indian Ocean Dipole (IOD) in the model. We show that, during the negative phase of EQUINOO/IOD, northward propagating TCZs remained stationary over the Bay of Bengal for longer period compared to the positive phase of EQUINOO/IOD. As a result, compared to the positive phase of EQUINOO/IOD, during a negative phase of EQUINOO/IOD, more westward propagating synoptic scale systems originated from the vicinity of TCZ and moved on to the core monsoon region, which resulted in higher rainfall over this region in the CFS. We further show that frequent, though short-lived, westward propagating systems, generated near the vicinity of TCZ over the Bay moved onto the mainland were responsible for less number of break monsoon spells during the negative phase of EQUINOO/IOD in the model hindcasts. This study underlines the necessity for improving the skill of the coupled models, particularly CFS model, to simulate the links between EQUINOO/IOD and the Indian summer monsoon for reliable predictions of seasonal and intraseasonal variation of Indian summer monsoon rainfall.

Immunodominant role of CCHA subunit of Concholepas hemocyanin is associated with unique biochemical properties.

PubMed

Becker, María Inés; Fuentes, Alejandra; Del Campo, Miguel; Manubens, Augusto; Nova, Esteban; Oliva, Harold; Faunes, Fernando; Valenzuela, María Antonieta; Campos-Vallette, Marcelo; Aliaga, Alvaro; Ferreira, Jorge; De Ioannes, Alfredo E; De Ioannes, Pablo; Moltedo, Bruno

2009-03-01

Hemocyanin, the oxygen transporter metallo-glycoprotein from mollusks, shows strong relationship between its notable structural features and intrinsic immunomodulatory effects. Here we investigated the individual contribution of CCHA and CCHB subunits from Concholepas hemocyanin (CCH) to in vivo humoral immune response and their pre-clinical evaluation as immunotherapeutic agent in a mice bladder cancer model, in relation to their biochemical properties. To this end, subunits were purified and well characterized. Homogeneous subunits were obtained by anionic exchange chromatography, and its purity assessed by electrophoretic and immunochemical methods. While each CCH subunit contains eight functional units showing partial cross reaction, the vibrational spectral analysis showed several spectral differences, suggesting structural differences between them. In addition, we demonstrated differences in the carbohydrate content: CCHA had a 3.6% w/w sugar with both N- and O-linked moieties. In turn, CCHB had a 2.5% w/w sugar with N-linked, while O-linked moieties were nearly absent. Considering these differences, it was not possible to predict a priori whether the immunogenic and immunotherapeutic properties of subunits might be similar. Surprisingly, both subunits by itself induced a humoral response, and showed an antitumor effect in the bladder carcinoma cell line MBT-2. However, when immunologic parameters were analyzed, CCHA showed better efficiency than CCHB. No allergic reactions or any toxic effects were observed in mice treated with CCHA, sustaining its potential therapeutic use. Our study supports that CCHA subunit accounts for the most important features involved in the immunogenicity of CCH, such as better hydrophilicity and higher content of carbohydrates.

Three-dimensional Architecture of Hair-bundle Linkages Revealed by Electron-microscopic Tomography

PubMed Central

Auer, Manfred; Koster, Abrahram J.; Ziese, Ulrike; Bajaj, Chandrajit; Volkmann, Niels; Wang, Da Neng

2008-01-01

The senses of hearing and balance rest upon mechanoelectrical transduction by the hair bundles of hair cells in the inner ear. Located at the apical cellular surface, each hair bundle comprises several tens of stereocilia and a single kinocilium that are interconnected by extracellular proteinaceous links. Using electron-microscopic tomography of bullfrog saccular sensory epithelia, we examined the three-dimensional structures of basal links, kinociliary links, and tip links. We observed significant differences in the appearances and dimensions of these three structures and found two distinct populations of tip links suggestive of the involvement of different proteins, splice variants, or protein–protein interactions. We noted auxiliary links connecting the upper portions of tip links to the taller stereocilia. Tip links and auxiliary links show a tendency to adopt a globular conformation when disconnected from the membrane surface. PMID:18421501

Cross-Linked Enzyme Aggregates for Applications in Aqueous and Nonaqueous Media.

PubMed

Roy, Ipsita; Mukherjee, Joyeeta; Gupta, Munishwar N

2017-01-01

Extensive cross-linking of a precipitate of a protein by a cross-linking reagent (glutaraldehyde has been most commonly used) creates an insoluble enzyme preparation called cross-linked enzyme aggregates (CLEAs). CLEAs show high stability and performance in conventional aqueous as well as nonaqueous media. These are also stable at fairly high temperatures. CLEAs with more than one kind of enzyme activity can be prepared, and such CLEAs are called combi-CLEAs or multipurpose CLEAs. Extent of cross-linking often influences their morphology, stability, activity, and enantioselectivity.

Smart surface coating of drug nanoparticles with cross-linkable polyethylene glycol for bio-responsive and highly efficient drug delivery

NASA Astrophysics Data System (ADS)

Wei, Weijia; Zhang, Xiujuan; Chen, Xianfeng; Zhou, Mengjiao; Xu, Ruirui; Zhang, Xiaohong

2016-04-01

Many drug molecules can be directly used as nanomedicine without the requirement of any inorganic or organic carriers such as silica and liposome nanostructures. This new type of carrier-free drug nanoparticles (NPs) has great potential in clinical treatment because of its ultra-high drug loading capacity and biodegradability. For practical applications, it is essential for such nanomedicine to possess robust stability and minimal premature release of therapeutic molecules during circulation in the blood stream. To meet this requirement, herein, we develop GSH-responsive and crosslinkable amphiphilic polyethylene glycol (PEG) molecules to modify carrier-free drug NPs. These PEG molecules can be cross-linked on the surface of the NPs to endow them with greater stability and the cross-link is sensitive to intracellular environment for bio-responsive drug release. With this elegant design, our experimental results show that the liberation of DOX from DOX-cross-linked PEG NPs is dramatically slower than that from DOX-non-cross-linked PEG NPs, and the DOX release profile can be controlled by tuning the concentration of the reducing agent to break the cross-link between PEG molecules. More importantly, in vivo studies reveal that the DOX-cross-linked PEG NPs exhibit favorable blood circulation half-life (>4 h) and intense accumulation in tumor areas, enabling effective anti-cancer therapy. We expect this work will provide a powerful strategy for stabilizing carrier-free nanomedicines and pave the way to their successful clinical applications in the future.Many drug molecules can be directly used as nanomedicine without the requirement of any inorganic or organic carriers such as silica and liposome nanostructures. This new type of carrier-free drug nanoparticles (NPs) has great potential in clinical treatment because of its ultra-high drug loading capacity and biodegradability. For practical applications, it is essential for such nanomedicine to possess robust stability and minimal premature release of therapeutic molecules during circulation in the blood stream. To meet this requirement, herein, we develop GSH-responsive and crosslinkable amphiphilic polyethylene glycol (PEG) molecules to modify carrier-free drug NPs. These PEG molecules can be cross-linked on the surface of the NPs to endow them with greater stability and the cross-link is sensitive to intracellular environment for bio-responsive drug release. With this elegant design, our experimental results show that the liberation of DOX from DOX-cross-linked PEG NPs is dramatically slower than that from DOX-non-cross-linked PEG NPs, and the DOX release profile can be controlled by tuning the concentration of the reducing agent to break the cross-link between PEG molecules. More importantly, in vivo studies reveal that the DOX-cross-linked PEG NPs exhibit favorable blood circulation half-life (>4 h) and intense accumulation in tumor areas, enabling effective anti-cancer therapy. We expect this work will provide a powerful strategy for stabilizing carrier-free nanomedicines and pave the way to their successful clinical applications in the future. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr09167e

In-Silico Design, Synthesis and Evaluation of a Nanostructured Hydrogel as a Dimethoate Removal Agent.

PubMed

Avila-Salas, Fabian; Marican, Adolfo; Villaseñor, Jorge; Arenas-Salinas, Mauricio; Argandoña, Yerko; Caballero, Julio; Durán-Lara, Esteban F

2018-01-04

This study describes the in-silico design, synthesis, and evaluation of a cross-linked PVA hydrogel (CLPH) for the absorption of organophosphorus pesticide dimethoate from aqueous solutions. The crosslinking effectiveness of 14 dicarboxilic acids was evaluated through in-silico studies using semiempirical quantum mechanical calculations. According to the theoretical studies, the nanopore of PVA cross-linked with malic acid (CLPH-MA) showed the best interaction energy with dimethoate. Later, using all-atom molecular dynamics simulations, three hydrogels with different proportions of PVA:MA (10:2, 10:4, and 10:6) were used to evaluate their interactions with dimethoate. These results showed that the suitable crosslinking degree for improving the affinity for the pesticide was with 20% ( W %) of the cross-linker. In the experimental absorption study, the synthesized CLPH-MA20 recovered 100% of dimethoate from aqueous solutions. Therefore, the theoretical data were correlated with the experimental studies. Surface morphology of CLPH-MA20 by Scanning Electron Microscopy (SEM) was analyzed. In conclusion, the ability of CLPH-MA20 to remove dimethoate could be used as a technological alternative for the treatment of contaminated water.

In-Silico Design, Synthesis and Evaluation of a Nanostructured Hydrogel as a Dimethoate Removal Agent

PubMed Central

Avila-Salas, Fabian; Marican, Adolfo; Villaseñor, Jorge; Argandoña, Yerko

2018-01-01

This study describes the in-silico design, synthesis, and evaluation of a cross-linked PVA hydrogel (CLPH) for the absorption of organophosphorus pesticide dimethoate from aqueous solutions. The crosslinking effectiveness of 14 dicarboxilic acids was evaluated through in-silico studies using semiempirical quantum mechanical calculations. According to the theoretical studies, the nanopore of PVA cross-linked with malic acid (CLPH-MA) showed the best interaction energy with dimethoate. Later, using all-atom molecular dynamics simulations, three hydrogels with different proportions of PVA:MA (10:2, 10:4, and 10:6) were used to evaluate their interactions with dimethoate. These results showed that the suitable crosslinking degree for improving the affinity for the pesticide was with 20% (W%) of the cross-linker. In the experimental absorption study, the synthesized CLPH-MA20 recovered 100% of dimethoate from aqueous solutions. Therefore, the theoretical data were correlated with the experimental studies. Surface morphology of CLPH-MA20 by Scanning Electron Microscopy (SEM) was analyzed. In conclusion, the ability of CLPH-MA20 to remove dimethoate could be used as a technological alternative for the treatment of contaminated water. PMID:29300312

Siblings, parents, and partners: family relationships within a longitudinal community study. ALSPAC study team. Avon Longitudinal Study of Pregnancy and Childhood.

PubMed

Dunn, J; Deater-Deckard, K; Pickering, K; Golding, J

1999-10-01

Links between sibling relationships, mother-partner, and parent-child relationships were studied in a longitudinal community sample of 3681 sibling pairs. Individual differences in sibling relationship quality were related to mother-partner affection and hostility assessed 4 years earlier, to contemporary parent-child negativity, and to indices of social adversity. Evidence for both direct and indirect pathways (via parent-child relations) linking mother-partner and sibling relations were found. Comparisons of prediction for non-stepfamilies and stepfather families showed similarities in patterns of association, but also differences: In stepfather families, mother-partner hostility was unrelated to parent-child negativity and sibling relationship quality. Both positivity and negativity towards young siblings decreased with the age of older siblings, and older sisters were more positive than older brothers.

Localization of PDZD7 to the stereocilia ankle-link associates this scaffolding protein with the Usher syndrome protein network.

PubMed

Grati, M'hamed; Shin, Jung-Bum; Weston, Michael D; Green, James; Bhat, Manzoor A; Gillespie, Peter G; Kachar, Bechara

2012-10-10

Usher syndrome is the leading cause of genetic deaf-blindness. Monoallelic mutations in PDZD7 increase the severity of Usher type II syndrome caused by mutations in USH2A and GPR98, which respectively encode usherin and GPR98. PDZ domain-containing 7 protein (PDZD7) is a paralog of the scaffolding proteins harmonin and whirlin, which are implicated in Usher type 1 and type 2 syndromes. While usherin and GPR98 have been reported to form hair cell stereocilia ankle-links, harmonin localizes to the stereocilia upper tip-link density and whirlin localizes to both tip and ankle-link regions. Here, we used mass spectrometry to show that PDZD7 is expressed in chick stereocilia at a comparable molecular abundance to GPR98. We also show by immunofluorescence and by overexpression of tagged proteins in rat and mouse hair cells that PDZD7 localizes to the ankle-link region, overlapping with usherin, whirlin, and GPR98. Finally, we show in LLC-PK1 cells that cytosolic domains of usherin and GPR98 can bind to both whirlin and PDZD7. These observations are consistent with PDZD7 being a modifier and candidate gene for USH2, and suggest that PDZD7 is a second scaffolding component of the ankle-link complex.

R213W mutation in the retinoschisis 1 gene causes X-linked juvenile retinoschisis in a large Chinese family.

PubMed

Xu, Jun; Gu, Hong; Ma, Kai; Liu, Xipu; Snellingen, Torkel; Sun, Erdan; Wang, Ningli; Liu, Ningpu

2010-08-12

We identified a large Chinese family with X-linked juvenile retinoschisis. The purpose of this study was to report the clinical findings of the family and to identify the genetic mutation by screening the retinoschisis 1 (RS1) gene. Family history was collected and all family members underwent routine ophthalmic examination. Venous blood was collected from family members and genomic DNA was extracted. The exons of RS1 were screened by PCR followed by direct sequencing and/or restriction enzyme digestion. The pedigree of interest was a four-generation family with 52 family members, including seven affected individuals. The proband was a 5-year-old boy showing highly elevated bullous retinoschisis with moderate vitreous hemorrhage in both eyes. Vitrectomy was performed in the left eye of the proband. Five affected males showed large peripheral retinoschisis in both eyes, either involving the macula or combined with foveal stellate cystic change. One of the affected family members showed only a foveal stellate cystic change in both eyes without periphery retinoschisis. Visual acuity of affected individuals ranged from hand motion to 0.4. The R213W mutation in exon 6 of RS1 was identified in all affected individuals, predicting an amino acid substitution of arginine to tryptophan at codon 213. Our data show that the R213W mutation in RS1 causes various severities of retinoschisis in a large Chinese family, providing further evidence for X-linked juvenile retinoschisis phenotypic variability.

Oxytonergic circuitry sustains and enables creative cognition in humans

PubMed Central

Baas, Matthijs; Roskes, Marieke; Sligte, Daniel J.; Ebstein, Richard P.; Chew, Soo Hong; Tong, Terry; Jiang, Yushi; Mayseless, Naama; Shamay-Tsoory, Simone G.

2014-01-01

Creativity enables humans to adapt flexibly to changing circumstances, to manage complex social relations and to survive and prosper through social, technological and medical innovations. In humans, chronic, trait-based as well as temporary, state-based approach orientation has been linked to increased capacity for divergent rather than convergent thinking, to more global and holistic processing styles and to more original ideation and creative problem solving. Here, we link creative cognition to oxytocin, a hypothalamic neuropeptide known to up-regulate approach orientation in both animals and humans. Study 1 (N = 492) showed that plasma oxytocin predicts novelty-seeking temperament. Study 2 (N = 110) revealed that genotype differences in a polymorphism in the oxytocin receptor gene rs1042778 predicted creative ideation, with GG/GT-carriers being more original than TT-carriers. Using double-blind placebo-controlled between-subjects designs, Studies 3–6 (N = 191) finally showed that intranasal oxytocin (vs matching placebo) reduced analytical reasoning, and increased holistic processing, divergent thinking and creative performance. We conclude that the oxytonergic circuitry sustains and enables the day-to-day creativity humans need for survival and prosperity and discuss implications. PMID:23863476

Genome-wide association study of serum coenzyme Q10 levels identifies susceptibility loci linked to neuronal diseases.

PubMed

Degenhardt, Frauke; Niklowitz, Petra; Szymczak, Silke; Jacobs, Gunnar; Lieb, Wolfgang; Menke, Thomas; Laudes, Matthias; Esko, Tõnu; Weidinger, Stephan; Franke, Andre; Döring, Frank; Onur, Simone

2016-07-01

Coenzyme Q 10 (CoQ 10 ) is a lipophilic redox molecule that is present in membranes of almost all cells in human tissues. CoQ 10 is, amongst other functions, essential for the respiratory transport chain and is a modulator of inflammatory processes and gene expression. Rare monogenetic CoQ 10 deficiencies show noticeable symptoms in tissues (e.g. kidney) and cell types (e.g. neurons) with a high energy demand. To identify common genetic variants influencing serum CoQ 10 levels, we performed a fixed effects meta-analysis in two independent cross-sectional Northern German cohorts comprising 1300 individuals in total. We identified two genome-wide significant susceptibility loci. The best associated single nucleotide polymorphism (SNP) was rs9952641 (P value = 1.31 × 10 - 8 , β = 0.063, CI 0.95 [0.041, 0.085]) within the COLEC12 gene on chromosome 18. The SNP rs933585 within the NRXN-1 gene on chromosome 2 also showed genome wide significance (P value = 3.64 × 10 - 8 , β = -0.034, CI 0.95 [-0.046, -0.022]). Both genes have been previously linked to neuronal diseases like Alzheimer's disease, autism and schizophrenia. Among our 'top-10' associated variants, four additional loci with known neuronal connections showed suggestive associations with CoQ 10 levels. In summary, this study demonstrates that serum CoQ 10 levels are associated with common genetic loci that are linked to neuronal diseases. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Synthesis of novel chromenones linked to 1,2,3-triazole ring system: Investigation of biological activities against Alzheimer's disease.

PubMed

Saeedi, Mina; Safavi, Maliheh; Karimpour-Razkenari, Elahe; Mahdavi, Mohammad; Edraki, Najmeh; Moghadam, Farshad Homayouni; Khanavi, Mahnaz; Akbarzadeh, Tahmineh

2017-02-01

In this work, novel chromenones linked to 1,2,3-triazole ring system were synthesized and evaluated for their anti-ChE activity. Among them, N-((1-(2-chlorobenzyl)-1H-1,2,3-triazol-5-yl)methyl)-8-methoxy-2-oxo-2H-chromene-3-carboxamide (6m) showed good anti-acetylcholinesterase activity (IC 50 =15.42μM). Also, compound 6m demonstrated neuroprotective effect against H 2 O 2 -induced cell death in PC12 neurons, however, it showed no beta-secretase (BACE1) inhibitory activity. Docking and kinetic studies separately confirmed dual binding activity of compound 6m since it targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. Copyright © 2016 Elsevier Inc. All rights reserved.

Robust cross-links in molluscan adhesive gels: Testing for contributions from hydrophobic and electrostatic interactions

PubMed Central

Smith, A.M.; Robinson, T. M.; Salt, M. D.; Hamilton, K. S.; Silvia, B. E.; Blasiak, R.

2009-01-01

The cross-linking interactions that provide cohesive strength to molluscan adhesive gels were investigated. Metal-based interactions have been shown to play an important role in the glue of the slug Arion subfuscus (Draparnaud), but other types of interactions may also contribute to the glue's strength and their role has not been investigated. This study shows that treatments that normally disrupt hydrophobic or electrostatic interactions have little to no effect on the slug glue. High salt concentrations and non-ionic detergent do not affect the solubility of the proteins in the glue or the ability of the glue proteins to stiffen gels. In contrast, metal chelation markedly disrupts the gel. Experiments with gel filtration chromatography identify a 40 kDa protein that is a central component of the cross-links in the glue. This 40 kDa protein forms robust macromolecular aggregations that are stable even in the presence of high concentrations of salt, non-ionic detergent, urea or metal chelators. Metal chelation during glue secretion, however, may block some of these cross-links. Such robust, non-specific interactions in an aqueous environment are highly unusual for hydrogels and reflect an intriguing cross-linking mechanism. PMID:18952190

Wake Vortex Transport and Decay in Ground Effect: Vortex Linking with the Ground

NASA Technical Reports Server (NTRS)

Proctor, Fred H.; Hamilton, David W.; Han, Jongil

2000-01-01

Numerical simulations are carried out with a three-dimensional Large-Eddy Simulation (LES) model to explore the sensitivity of vortex decay and transport in ground effect (IGE). The vortex decay rates are found to be strongly enhanced following maximum descent into ground effect. The nondimensional decay rate is found to be insensitive to the initial values of circulation, height, and vortex separation. The information gained from these simulations is used to construct a simple decay relationship. This relationship compares well with observed data from an IGE case study. Similarly, a relationship for lateral drift due to ground effect is constructed from the LES data. In the second part of this paper, vortex linking with the ground is investigated. Our numerical simulations of wake vortices for IGE show that a vortex may link with its image beneath the ground, if the intensity of the ambient turbulence is moderate to high. This linking with the ground (which is observed in real cases)gives the appearance of a vortex tube that bends to become vertically oriented and which terminates at the ground. From the simulations conducted, the linking time for vortices in the free atmosphere; i.e., a function of ambient turbulence intensity.

Robust cross-links in molluscan adhesive gels: testing for contributions from hydrophobic and electrostatic interactions.

PubMed

Smith, A M; Robinson, T M; Salt, M D; Hamilton, K S; Silvia, B E; Blasiak, R

2009-02-01

The cross-linking interactions that provide cohesive strength to molluscan adhesive gels were investigated. Metal-based interactions have been shown to play an important role in the glue of the slug Arion subfuscus (Draparnaud), but other types of interactions may also contribute to the glue's strength and their role has not been investigated. This study shows that treatments that normally disrupt hydrophobic or electrostatic interactions have little to no effect on the slug glue. High salt concentrations and non-ionic detergent do not affect the solubility of the proteins in the glue or the ability of the glue proteins to stiffen gels. In contrast, metal chelation markedly disrupts the gel. Experiments with gel filtration chromatography identify a 40 kDa protein that is a central component of the cross-links in the glue. This 40 kDa protein forms robust macromolecular aggregations that are stable even in the presence of high concentrations of salt, non-ionic detergent, urea or metal chelators. Metal chelation during glue secretion, however, may block some of these cross-links. Such robust, non-specific interactions in an aqueous environment are highly unusual for hydrogels and reflect an intriguing cross-linking mechanism.

Beyond human error taxonomies in assessment of risk in sociotechnical systems: a new paradigm with the EAST 'broken-links' approach.

PubMed

Stanton, Neville A; Harvey, Catherine

2017-02-01

Risk assessments in Sociotechnical Systems (STS) tend to be based on error taxonomies, yet the term 'human error' does not sit easily with STS theories and concepts. A new break-link approach was proposed as an alternative risk assessment paradigm to reveal the effect of information communication failures between agents and tasks on the entire STS. A case study of the training of a Royal Navy crew detecting a low flying Hawk (simulating a sea-skimming missile) is presented using EAST to model the Hawk-Frigate STS in terms of social, information and task networks. By breaking 19 social links and 12 task links, 137 potential risks were identified. Discoveries included revealing the effect of risk moving around the system; reducing the risks to the Hawk increased the risks to the Frigate. Future research should examine the effects of compounded information communication failures on STS performance. Practitioner Summary: The paper presents a step-by-step walk-through of EAST to show how it can be used for risk assessment in sociotechnical systems. The 'broken-links' method takes a systemic, rather than taxonomic, approach to identify information communication failures in social and task networks.

Tunable Elastomers with an Antithrombotic Component for Cardiovascular Applications.

PubMed

Stahl, Alexander M; Yang, Yunzhi Peter

2018-05-31

This study reports the development of a novel family of biodegradable polyurethanes for use as tissue engineered cardiovascular scaffolds or blood-contacting medical devices. Covalent incorporation of the antiplatelet agent dipyridamole into biodegradable polycaprolactone-based polyurethanes yields biocompatible materials with improved thromboresistance and tunable mechanical strength and elasticity. Altering the ratio of the dipyridamole to the diisocyanate linking unit and the polycaprolactone macromer enables control over both the drug content and the polymer cross-link density. Covalent cross-linking in the materials achieves significant elasticity and a tunable range of elastic moduli similar to that of native cardiovascular tissues. Interestingly, the cross-link density of the polyurethanes is inversely related to the elastic modulus, an effect attributed to decreasing crystallinity in the more cross-linked polymers. In vitro characterization shows that the antiplatelet agent is homogeneously distributed in the materials and is released slowly throughout the polymer degradation process. The drug-containing polyurethanes support endothelial cell and vascular smooth muscle cell proliferation, while demonstrating reduced levels of platelet adhesion and activation, supporting their candidacy as promising substrates for cardiovascular tissue engineering. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The intersubjective links in perversion.

PubMed

Eiguer, Alberto

2007-10-01

The author studies the intersubjective links which the pervert maintains with analyst or partner, attempting to indicate the differences between the investments in each case. Rather than accepting that empathy towards these patients is impossible to achieve and disturbs the countertransference profoundly, it attempts to show that these difficulties may be overcome if they are reinterpreted in the light of the theory of the intersubjective link. The author examines the theories and the practice of intersubjectivity and gives a definition of his approach to the link between two subjects. He applies these ideas to the case of a sexually masochistic female patient. The countertransference is marked successively by indifference, rejection and smothering. The analysis of the analyst's dream allows the situation to evolve. Failures in primary identification can result in domination over others and utilitarianism. The author examines the place of the challenge to the 'Law' and the father (in the attempt by the patient to put a theory to the test) in order to identify the figure of the witness in the pervert's intersubjective links. The desire of the transference would be marked by the figure of the witness rather than by that of the analyst as accomplice.

A flight investigation of simulated data link communications during single-pilot IFR flight

NASA Technical Reports Server (NTRS)

Parker, J. F.; Duffy, J. W.; Christensen, D. G.

1983-01-01

A Flight Data Console (FDC) was developed to allow simulation of a digital communications link to replace the current voice communication system used in air traffic control (ATC). The voice system requires manipulation of radio equipment, read-back of clearances, and mental storage of critical information items, all contributing to high workload, particularly during single-pilot operations. This was an inflight study to determine how a digital communications system might reduce cockpit workload, improve flight proficiency, and be accepted by general aviation pilots. Results show that instrument flight, including approach and landing, can be accomplished quite effectively using a digital data link system for ATC communications. All pilots expressed a need for a back-up voice channel. When included, this channel was used sparingly and principally to confirm any item of information about which there might be uncertainty.

Intracellular degradation of microspheres based on cross-linked dextran hydrogels or amphiphilic block copolymers: A comparative Raman microscopy study

PubMed Central

van Manen, Henk-Jan; van Apeldoorn, Aart A; Verrijk, Ruud; van Blitterswijk, Clemens A; Otto, Cees

2007-01-01

Micro- and nanospheres composed of biodegradable polymers show promise as versatile devices for the controlled delivery of biopharmaceuticals. Whereas important properties such as drug release profiles, biocompatibility, and (bio)degradability have been determined for many types of biodegradable particles, information about particle degradation inside phagocytic cells is usually lacking. Here, we report the use of confocal Raman microscopy to obtain chemical information about cross-linked dextran hydrogel microspheres and amphiphilic poly(ethylene glycol)-terephthalate/poly(butylene terephthalate) (PEGT/PBT) microspheres inside RAW 264.7 macrophage phagosomes. Using quantitative Raman microspectroscopy, we show that the dextran concentration inside phagocytosed dextran microspheres decreases with cell incubation time. In contrast to dextran microspheres, we did not observe PEGT/PBT microsphere degradation after 1 week of internalization by macrophages, confirming previous studies showing that dextran microsphere degradation proceeds faster than PEGT/PBT degradation. Raman microscopy further showed the conversion of macrophages to lipid-laden foam cells upon prolonged incubation with both types of microspheres, suggesting that a cellular inflammatory response is induced by these biomaterials in cell culture. Our results exemplify the power of Raman microscopy to characterize microsphere degradation in cells and offer exciting prospects for this technique as a noninvasive, label-free optical tool in biomaterials histology and tissue engineering. PMID:17722552

Development and Analytical Characterization of Pegunigalsidase Alfa, a Chemically Cross-Linked Plant Recombinant Human α-Galactosidase-A for Treatment of Fabry Disease.

PubMed

Ruderfer, Ilya; Shulman, Avidor; Kizhner, Tali; Azulay, Yaniv; Nataf, Yakir; Tekoah, Yoram; Shaaltiel, Yoseph

2018-05-16

The current treatment of Fabry disease by enzyme replacement therapy with commercially available recombinant human α-Galactosidase A shows a continuous deterioration of the disease patients. Human recombinant α-Galactosidase A is a homodimer with noncovalently bound subunits and is expressed in the ProCellEx plant cell-based protein expression platform to produce pegunigalsidase alfa. The effect of covalent bonding between two α-Galactosidase A subunits by PEG-based cross-linkers of various lengths was evaluated in this study. The results show that cross-linking by a bifunctional PEG polymer of 2000 Da produces a more stable protein with improved pharmacokinetic and biodistribution properties. The chemical modification did not influence the tertiary protein structure but led to an increased thermal stability and showed partial masking of immune epitopes. The developed pegunigalsidase alfa is currently tested in phase III clinical trials and has a potential to show superior efficacy versus the currently used enzyme replacement therapies in the treatment of Fabry disease patients.

Tracking the Oxygen Status in the Cell Nucleus with a Hoechst-Tagged Phosphorescent Ruthenium Complex.

PubMed

Hara, Daiki; Umehara, Yui; Son, Aoi; Asahi, Wataru; Misu, Sotaro; Kurihara, Ryohsuke; Kondo, Teruyuki; Tanabe, Kazuhito

2018-05-04

Molecular oxygen in living cells is distributed and consumed inhomogeneously, depending on the activity of each organelle. Therefore, tractable methods that can be used to monitor the oxygen status in each organelle are needed to understand cellular function. Here we report the design of a new oxygen-sensing probe for use in the cell nucleus. We prepared "Ru-Hoechsts", each consisting of a phosphorescent ruthenium complex linked to a Hoechst 33258 moiety, and characterized their properties as oxygen sensors. The Hoechst unit shows strong DNA-binding properties in the nucleus, and the ruthenium complex shows oxygen-dependent phosphorescence. Thus, Ru-Hoechsts accumulated in the cell nucleus and showed oxygen-dependent signals that could be monitored. Of the Ru-Hoechsts prepared in this study, Ru-Hoechst b, in which the ruthenium complex and the Hoechst unit were linked through a hexyl chain, showed the most suitable properties for monitoring the oxygen status. Ru-Hoechsts are probes with high potential for visualizing oxygen fluctuations in the nucleus. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Environmental and genetic determinants of innovativeness in a natural population of birds

PubMed Central

Quinn, John L.; Cole, Ella F.; Reed, Thomas E.

2016-01-01

Much of the evidence for the idea that individuals differ in their propensity to innovate and solve new problems has come from studies on captive primates. Increasingly, behavioural ecologists are studying innovativeness in wild populations, and uncovering links with functional behaviour and fitness-related traits. The relative importance of genetic and environmental factors in driving this variation, however, remains unknown. Here, we present the results of the first large-scale study to examine a range of causal factors underlying innovative problem-solving performance (PSP) among 831 great tits (Parus major) temporarily taken into captivity. Analyses show that PSP in this population: (i) was linked to a variety of individual factors, including age, personality and natal origin (immigrant or local-born); (ii) was influenced by natal environment, because individuals had a lower PSP when born in poor-quality habitat, or where local population density was high, leading to cohort effects. Links with many of the individual and environmental factors were present only in some years. In addition, PSP (iii) had little or no measurable heritability, as estimated by a Bayesian animal model; and (iv) was not influenced by maternal effects. Despite previous reports of links between PSP and a range of functional traits in this population, the analyses here suggest that innovativeness had weak if any evolutionary potential. Instead most individual variation was caused by phenotypic plasticity driven by links with other behavioural traits and by environmentally mediated developmental stress. Heritability estimates are population, time and context specific, however, and more studies are needed to determine the generality of these effects. Our results shed light on the causes of innovativeness within populations, and add to the debate on the relative importance of genetic and environmental factors in driving phenotypic variation within populations. PMID:26926275

High rate of translocation-based gene birth on the Drosophila Y chromosome.

PubMed

Tobler, Ray; Nolte, Viola; Schlötterer, Christian

2017-10-31

The Y chromosome is a unique genetic environment defined by a lack of recombination and male-limited inheritance. The Drosophila Y chromosome has been gradually acquiring genes from the rest of the genome, with only seven Y-linked genes being gained over the past 63 million years (0.12 gene gains per million years). Using a next-generation sequencing (NGS)-powered genomic scan, we show that gene transfers to the Y chromosome are much more common than previously suspected: at least 25 have arisen across three Drosophila species over the past 5.4 million years (1.67 per million years for each lineage). The gene transfer rate is significantly lower in Drosophila melanogaster than in the Drosophila simulans clade, primarily due to Y-linked retrotranspositions being significantly more common in the latter. Despite all Y-linked gene transfers being evolutionarily recent (<1 million years old), only three showed evidence for purifying selection ( ω ≤ 0.14). Thus, although the resulting Y-linked functional gene acquisition rate (0.25 new genes per million years) is double the longer-term estimate, the fate of most new Y-linked genes is defined by rapid degeneration and pseudogenization. Our results show that Y-linked gene traffic, and the molecular mechanisms governing these transfers, can diverge rapidly between species, revealing the Drosophila Y chromosome to be more dynamic than previously appreciated. Our analytical method provides a powerful means to identify Y-linked gene transfers and will help illuminate the evolutionary dynamics of the Y chromosome in Drosophila and other species. Copyright © 2017 the Author(s). Published by PNAS.

Age differences in search of web pages: the effects of link size, link number, and clutter.

PubMed

Grahame, Michael; Laberge, Jason; Scialfa, Charles T

2004-01-01

Reaction time, eye movements, and errors were measured during visual search of Web pages to determine age-related differences in performance as a function of link size, link number, link location, and clutter. Participants (15 young adults, M = 23 years; 14 older adults, M = 57 years) searched Web pages for target links that varied from trial to trial. During one half of the trials, links were enlarged from 10-point to 12-point font. Target location was distributed among the left, center, and bottom portions of the screen. Clutter was manipulated according to the percentage of used space, including graphics and text, and the number of potentially distracting nontarget links was varied. Increased link size improved performance, whereas increased clutter and links hampered search, especially for older adults. Results also showed that links located in the left region of the page were found most easily. Actual or potential applications of this research include Web site design to increase usability, particularly for older adults.

Study on polymethylmethacrylate ring in protecting limbal stem cells during collagen cross-linking.

PubMed

Jeyalatha, Vimalin; Jambulingam, Malathi; Gupta, Nidhi; Padmanabhan, Prema; Madhavan, Hajib N

2013-01-01

The UV rays used in the collagen cross-linking (CXL) procedure seem to cause potential damage to the limbal stem cells. This study was designed to evaluate the ability of polymethylmethacrylate (PMMA) hemiannulus as an alternative to protect corneal limbal stem cells during CXL. Ten freshly enucleated human cadaveric eyeballs were subjected to the corneal CXL procedure. The cadaveric eye ball was divided into 2 sectors: A and B. Sector A was left unprotected, while sector B was covered by a PMMA shield. Limbal biopsies from both sectors before and after the procedure were analyzed. Each limbal tissue was placed on human amniotic membrane (HAM) to check the cultivability and was subjected to marker studies using reverse transcriptase PCR. Before CXL, biopsies from both sectors showed growth on HAM. After CXL, biopsies from sector A showed no growth on HAM while 2 out of the 10 from sector B covered with the PMMA ring did show growth on HAM. The putative stem-cell marker ABCG2 was negative in all the samples from sector A after CXL and was positive in 2 out of the 10 samples from sector B. Covering the limbal region with PMMA offers partial protection of the limbus from the UV rays during the CXL procedure. © 2013 S. Karger AG, Basel.

The link between infertility and poverty: evidence from Bangladesh.

PubMed

Nahar, Papreen

2012-03-01

The link between high fertility and poverty is well established. However, this paper shows how infertility may also generate poverty among childless families in Bangladesh. An ethnographic study was conducted, involving various qualitative research methods that revealed economic consequences to be one of the crucial sequelae of childlessness in Bangladesh. This paper details how the poverty/fertility relationship is dependent on social and institutional characteristics, including patriarchal values, education, urban-rural location and health services. Empirical data show that childlessness generates poverty in various ways, including the deprivation of children's earnings, decline in women's mobility, demoralisation of men to earn an income, marriage devaluation by the husband, disbursements for treatment and denial of microcredit (very small loans to those in poverty, which support them to become self-employed to generate income). The current study shows that the infertility/poverty relationship is mostly contingent upon class and gender. It is therefore the rural poor childless women who are most badly affected economically in Bangladesh rather than the urban middle class childless women. In other words, this study reveal that along with gender, class plays a dominant role in terms of the economic consequences of childlessness in Bangladesh. It sheds light on a different and unusual aspect of poverty and aims to contribute to the gender discussion of livelihood and poverty.

Parathyroid Hormone, Cognitive Function and Dementia: A Systematic Review

PubMed Central

Lourida, Ilianna; Thompson-Coon, Jo; Dickens, Chris M.; Soni, Maya; Kuźma, Elżbieta; Kos, Katarina; Llewellyn, David J.

2015-01-01

Background Metabolic factors are increasingly recognized to play an important role in the pathogenesis of Alzheimer’s disease and dementia. Abnormal parathyroid hormone (PTH) levels play a role in neuronal calcium dysregulation, hypoperfusion and disrupted neuronal signaling. Some studies support a significant link between PTH levels and dementia whereas others do not. Methods We conducted a systematic review through January 2014 to evaluate the association between PTH and parathyroid conditions, cognitive function and dementia. Eleven electronic databases and citation indexes were searched including Medline, Embase and the Cochrane Library. Hand searches of selected journals, reference lists of primary studies and reviews were also conducted along with websites of key organizations. Two reviewers independently screened titles and abstracts of identified studies. Data extraction and study quality were performed by one and checked by a second reviewer using predefined criteria. A narrative synthesis was performed due to the heterogeneity of included studies. Results The twenty-seven studies identified were of low and moderate quality, and challenging to synthesize due to inadequate reporting. Findings from six observational studies were mixed but suggest a link between higher serum PTH levels and increased odds of poor cognition or dementia. Two case-control studies of hypoparathyroidism provide limited evidence for a link with poorer cognitive function. Thirteen pre-post surgery studies for primary hyperparathyroidism show mixed evidence for improvements in memory though limited agreement in other cognitive domains. There was some degree of cognitive impairment and improvement postoperatively in observational studies of secondary hyperparathyroidism but no evident pattern of associations with specific cognitive domains. Conclusions Mixed evidence offers weak support for a link between PTH, cognition and dementia due to the paucity of high quality research in this area. PMID:26010883

Study in mice shows that an aggressive type of breast cancer is linked to an inflammatory protein

Cancer.gov

Aberrant expression of an inflammatory protein, nitric oxide synthase 2 (NOS2), may enhance the progression and metastasis of an aggressive and less common form of breast cancer, known as the estrogen receptor-negative type of disease.

Health of Aging Parents and Childless Individuals

ERIC Educational Resources Information Center

Kendig, Hal; Dykstra, Pearl A.; van Gaalen, Ruben I.; Melkas, Tuula

2007-01-01

This article reviews and presents research findings on the relationships between parenthood and health over the life span. Existing research shows lacunae. The links between reproductive behavior and longevity generally focus on family size rather than contrasting parents and nonparents. Studies of marital status differentials in survival…

In Brief: Your Guide to Healthy Sleep

MedlinePlus

... make you irritable and is linked to poor behavior and trouble with relationships, especially among children and teens. People who chronically lack sleep are also more likely to become depressed. Health: Sleep is also important for good health. Studies show that not getting enough sleep or getting ...

Phenotypic heterogeneity and mutational spectrum in a cohort of 45 Italian males subjects with X-linked ectodermal dysplasia.

PubMed

Guazzarotti, L; Tadini, G; Mancini, G E; Giglio, S; Willoughby, C E; Callea, M; Sani, I; Nannini, P; Mameli, C; Tenconi, A A; Mauri, S; Bottero, A; Caimi, A; Morelli, M; Zuccotti, G V

2015-04-01

Ectodermal dysplasias (EDs) are a group of genetic disorders characterized by the abnormal development of the ectodermal-derived structures. X-linked hypohidrotic ectodermal dysplasia, resulting from mutations in ED1 gene, is the most common form. The main purpose of this study was to characterize the phenotype spectrum in 45 males harboring ED1 mutations. The study showed that in addition to the involvement of the major ectodermal tissues, the majority of patients also have alterations of several minor ectodermal-derived structures. Characterizing the clinical spectrum resulting from ED1 gene mutations improves diagnosis and can direct clinical care. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Shuttle/TDRSS Ku-band downlink study

NASA Technical Reports Server (NTRS)

Meyer, R.

1976-01-01

Assessing the adequacy of the baseline signal design approach, developing performance specifications for the return link hardware, and performing detailed design and parameter optimization tasks was accomplished by completing five specific study tasks. The results of these tasks show that the basic signal structure design is sound and that the goals can be met. Constraints placed on return link hardware by this structure allow reasonable specifications to be written so that no extreme technical risk areas in equipment design are foreseen. A third channel can be added to the PM mode without seriously degrading the other services. The feasibility of using only a PM mode was shown to exist, however, this will require use of some digital TV transmission techniques. Each task and its results are summarized.

Maternal mind-mindedness as a linking mechanism between childbirth-related posttraumatic stress symptoms and parenting stress.

PubMed

Camisasca, Elena; Procaccia, Rossella; Miragoli, Sarah; Valtolina, Giovanni Giulio; Di Blasio, Paola

2017-06-01

The researchers of this study have two aims. The first aim is to verify whether posttraumatic stress (PTS) symptoms, evaluated at 87 hours and at 3 months postpartum, are associated with maternal mind-mindedness (MM) and parenting stress, measured at 17 months postpartum. The second aim is to investigate, at 17 months, the predictive effects of PTS symptoms on the dimensions of parenting stress and to explore whether MM mediates these associations. Forty-one mother-infant dyads participated in the study. The results show that at 17 months, hyper-arousal symptoms predicted both MM and parenting stress. MM was a linking mechanism between maternal PTS symptoms and parenting stress.

Quiet Eye and Performance in Sport: A Meta-Analysis.

PubMed

Lebeau, Jean-Charles; Liu, Sicong; Sáenz-Moncaleano, Camilo; Sanduvete-Chaves, Susana; Chacón-Moscoso, Salvador; Becker, Betsy Jane; Tenenbaum, Gershon

2016-10-01

Research linking the "quiet eye" (QE) period to subsequent performance has not been systematically synthesized. In this paper we review the literature on the link between the two through nonintervention (Synthesis 1) and intervention (Synthesis 2) studies. In the first synthesis, 27 studies with 38 effect sizes resulted in a large mean effect (d = 1.04) reflecting differences between experts' and novices' QE periods, and a moderate effect size (d = 0.58) comparing QE periods for successful and unsuccessful performances within individuals. Studies reporting QE duration as a percentage of the total time revealed a larger mean effect size than studies reporting an absolute duration (in milliseconds). The second synthesis of 9 articles revealed very large effect sizes for both the quiet-eye period (d = 1.53) and performance (d = 0.84). QE also showed some ability to predict performance effects across studies.

The X linked recessive form of XY gonadal dysgenesis with a high incidence of gonadal germ cell tumours: clinical and genetic studies.

PubMed

Mann, J R; Corkery, J J; Fisher, H J; Cameron, A H; Mayerová, A; Wolf, U; Kennaugh, A A; Woolley, V

1983-08-01

Five phenotypic females in one family had the genotype 46,XY and all had gonadal germ cell tumours. Studies of the family pedigree suggest that this form of XY gonadal dysgenesis is inherited in an X linked recessive manner. G banding of elongated metaphase chromosomes from two subjects with XY gonadal dysgenesis and a female carrier showed no aberrations of the X chromosome. The titres of H-Y antigen in three girls with XY gonadal dysgenesis were in the male control range. Thus it appears that, in the X linked form, XY gonadal dysgenesis may be caused by a point deletion or mutation of a gene on the X chromosome, which controls the gonad specific receptor for the H-Y antigen. Studies of Xg blood groups were uninformative about linkage of Xg with the X borne gene causing the XY gonadal dysgenesis. Dermatoglyphic studies in the girls with XY gonadal dysgenesis and female carriers revealed high a-b palmar ridge counts and a tendency for the A mainline to terminate in the thenar area. Both of these features have been described in patients with Turner's syndrome.

Cutter Connectivity Bandwidth Study

NASA Astrophysics Data System (ADS)

2002-10-01

The goal of this study was to determine how much bandwidth is required for cutters to meet emerging data transfer requirements. The Cutter Connectivity Business Solutions Team with guidance front the Commandant's 5 Innovation Council sponsored this study. Today, many Coast Guard administrative and business functions are being conducted via electronic means. Although our larger cutters can establish part-time connectivity using commercial satellite communications (SATCOM) while underway, there are numerous complaints regarding poor application performance. Additionally, smaller cutters do not have any standard means of underway connectivity. The R&D study shows the most important factor affecting web performance and enterprise applications onboard cutters was latency. Latency describes the time it takes the signal to reach the satellite and come back down through space. The latency due to use of higher orbit satellites is causing poor application performance and inefficient use of expensive SATCOM links. To improve performance, the CC must, (1) reduce latency by using alternate communications links such as low-earth orbit satellites, (2) tailor applications to the SATCOM link and/or (3) optimize protocols used for data communication to minimize time required by present applications to establish communications between the user and the host systems.

Glycoprotein biosynthesis in animal cells grown in suspension culture. Assembly of lipid-linked saccharides and formation of protein-bound 'high-mannose' oligosaccharides.

PubMed Central

Bailey, D S; Burke, J; Sinclair, R; Mukherjee, B B

1981-01-01

Glycoprotein biosynthesis was studied with mouse L-cells grown in suspension culture. Glucose-deprived cells incorporated [3H]mannose into 'high-mannose' protein-bound oligosaccharides and a few relatively high-molecular-weight lipid-linked oligosaccharides. The latter were retained by DEAE-cellulose and turned over quite slowly during pulse--chase experiments. Increased heterogeneity in size of lipid-linked oligosaccharides developed during prolonged glucose deprivation. Sequential elongation of lipid-linked oligosaccharides was also observed, and conditions that prevented the assembly of the higher lipid-linked oligosaccharides also prevented the formation of the larger protein-bound 'high-mannose' oligosaccharides. In parallel experiments, [3H]mannose was incorporated into a total polyribosome fraction, suggesting that mannose residues were transferred co-translationally to nascent protein. Membrane preparations from these cells catalysed the assembly from UDP-N-acetyl-D-[6-3H]glucosamine and GDP-D-[U-14C]mannose of polyisoprenyl diphosphate derivatives whose oligosaccharide moieties were heterogeneous in size. Elongation of the N-acetyl-D-[6-3H]glucosamine-initiated glycolipids with mannose residues produced several higher lipid-linked oligosaccharides similar to those seen during glucose deprivation in vivo. Glucosylation of these mannose-containing oligosaccharides from UDP-D-[6-3H]glucose was restricted to those of a relatively high molecular weight. Protein-bound saccharides formed in vitro were mainly smaller in size than those assembled on the lipid acceptors. These results support the involvement of lipid-linked saccharides in the synthesis of asparagine-linked glycoproteins, but show both in vivo and in vitro that protein-bound 'high-mannose' oligosaccharide formation can occur independently of higher lipid-linked oligosaccharide synthesis. PMID:7306042

Evaluating the Effects of Riboflavin/UV-A and Rose-Bengal/Green Light Cross-Linking of the Rabbit Cornea by Noncontact Optical Coherence Elastography

PubMed Central

Singh, Manmohan; Li, Jiasong; Han, Zhaolong; Vantipalli, Srilatha; Liu, Chih-Hao; Wu, Chen; Raghunathan, Raksha; Aglyamov, Salavat R.; Twa, Michael D.; Larin, Kirill V.

2016-01-01

Purpose The purpose of this study was to use noncontact optical coherence elastography (OCE) to evaluate and compare changes in biomechanical properties that occurred in rabbit cornea in situ after corneal collagen cross-linking by either of two techniques: ultraviolet-A (UV-A)/riboflavin or rose-Bengal/green light. Methods Low-amplitude (≤10 μm) elastic waves were induced in mature rabbit corneas by a focused air pulse. Elastic wave propagation was imaged by a phase-stabilized swept source OCE (PhS-SSOCE) system. Corneas were then cross-linked by either of two methods: UV-A/riboflavin (UV-CXL) or rose-Bengal/green light (RGX). Phase velocities of the elastic waves were fitted to a previously developed modified Rayleigh-Lamb frequency equation to obtain the viscoelasticity of the corneas before and after the cross-linking treatments. Micro-scale depth-resolved phase velocity distribution revealed the depth-wise heterogeneity of both cross-linking techniques. Results Under standard treatment settings, UV-CXL significantly increased the stiffness of the corneas by ∼47% (P < 0.05), but RGX did not produce statistically significant increases. The shear viscosities were unaffected by either cross-linking technique. The depth-wise phase velocities showed that UV-CXL affected the anterior ∼34% of the corneas, whereas RGX affected only the anterior ∼16% of the corneas. Conclusions UV-CXL significantly strengthens the cornea, whereas RGX does not, and the effects of cross-linking by UV-CXL reach deeper into the cornea than cross-linking effects of RGX under similar conditions. PMID:27409461

Expression pattern of X-linked genes in sex chromosome aneuploid bovine cells.

PubMed

Basrur, Parvathi K; Farazmand, Ali; Stranzinger, Gerald; Graphodatskaya, Daria; Reyes, Ed R; King, W Allan

2004-01-01

Expression of the X-inactive specific transcript (XIST) gene is a prerequisite step for dosage compensation in mammals, accomplished by silencing one of the two X chromosomes in normal female diploid cells or all X chromosomes in excess of one in sex chromosome aneuploids. Our previous studies showing that XIST expression does not eventuate the inactivation of X-linked genes in fetal bovine testis had suggested that XIST expression may not be an indicator of X inactivation in this species. In this study, we used a semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) approach on cultures of bovine cells with varying sex chromosome constitution (XY, XX, XXY and XXX) to test whether the levels of XIST expressed conform to the number of late replicating (inactive) X chromosomes displayed by proliferating cells in these cultures. Expression patterns of four X-linked genes, including hypoxanthine phosphorybosyl transferase (HPRT), glucose-6-phosphate dehydrogenase (G6PD), zinc finger protein locus on the X (ZFX). and 'selected mouse cDNA on the X' (SMCX), in all these cells were also tested. Results showed that XIST expression was significantly higher (p < 0.05) in XXX cells compared to XX and XXY cells and that G6PD. HPRT, and SMCX loci are subject to X inactivation. The significantly higher levels of ZFX expressed in XXX cells compared to XX and XXY cells (p < 0.05) confirmed that this bovine locus, as human ZFX, escapes X inactivation. However, the levels of XIST and ZFX expressed were not proportional to the X chromosome load in these cells suggesting that X-linked loci escaping inactivation may be regulated at transcription (or post-transcription) level by mechanisms that prevent gene-specific product accumulation beyond certain levels in sex chromosome aneuploids.

Binuclear transition-metal complexes as new reagents for selective cross-linking of proteins. Coordination of cytochrome c to dirhodium(II). mu. -tetraacetate

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

Chen, J.; Kostic, N.M.

1988-07-27

This study introduces binuclear transition-metal complexes as reagents for selective covalent cross-linking of proteins. Incubation of horse cytochrome c (designated cyt) with Rh{sub 2}(OAc){sub 4} under mild conditions yields the diprotein complex, Rh{sub 2}(OAc){sub 4}(cyt){sub 2}, whose composition is established by size-exclusion chromatography, uv-vis spectroscopy, and {sup 1}H NMR spectroscopy. The protein molecules are coordinated to the Rh atoms via the imidazole (Im) rings of their His 33 residues, as shown by uv difference and {sup 1}H NMR spectroscopy, by the pH effect on the complex formation, and by the control experiments with tuna cytochrome c. The diprotein complex ismore » stable under ordinary conditions, and yet it can be cleaved, and the native protein recovered, by treatment with a suitable strong nucleophile. Spectroscopic and electrochemical measurements show that the structural and redox properties of cytochrome c are not perturbed significantly by cross-linking. Comparison between Rh{sub 2}(OAc){sub 4}(Im){sub 2} and Rh{sub 2}(OAc){sub 4}(cyt){sub 2} shows that the complex containing small ligands is not an entirely realistic model of the complex containing proteins. In particular, the enhanced stability of the latter toward hydrolysis may be due to steric bulk of the protein ligands and to hydrogen bonds that amino acid side chains may form with the inorganic link. Some of the findings of this study may pertain to the mechanism of antitumor action of the Rh{sub 2}(RCOO){sub 4} complexes. 86 refs., 2 tabs.« less

Dyslexia Linked to Visual Strengths Useful in Astronomy

NASA Astrophysics Data System (ADS)

Schneps, Matthew H.; Brockmole, J. R.; Rose, L. T.; Pomplun, M.; Sonnert, G.; Greenhill, L. J.

2011-05-01

Dyslexia is a hereditary neurological condition characterized by difficulties in reading, writing, and spelling. The fact that those with dyslexia include many accomplished scientists, including some recognized with a Nobel Prize, has prompted researchers to suggest that the neurology of dyslexia may predispose these individuals to advantages in visually-intensive domains such as science. Here, we report evidence of a link between dyslexia and abilities for visual processing useful in astronomy. First, we show that when images of natural scenes are Gaussian-blurred, so as to remove high-frequency detail (and resemble many astronomical images), college students with dyslexia significantly outperform those who are typical readers in learning the spatial contexts presented. Second, we show that when the threshold ability to detect radio signatures characteristic of black holes is measured in a laboratory simulation, astrophysicists with dyslexia significantly outperform those who are typical readers in this task when the visual periphery is important. In a third experiment, using eye-tracking technologies, we demonstrate that visual strategies significantly correlate with success in the black hole task, but that college students with dyslexia tend not to employ the strategies most likely to lead to success. Collectively, these studies suggest that dyslexia is linked to neurological advantages useful in astronomical careers, but that left to their own devices students with dyslexia may not benefit from these advantages without practice or training. These studies imply that many students who are struggling to read may find successful careers in astronomy or other fields that build on visual advantages linked to their reading disability, but that education and training may be vital in helping these students realize their strengths. This material is based upon work supported by the George E. Burch Fellowship (Smithsonian Institution) and the National Science Foundation under Grants HRD-0726032 and HRD-0930962.

High-resolution mapping of the x-linked hypohidrotic ectodermal dysplasia (EDA) locus

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

Zonana, J.; Jones, M.; Litt, M.

1992-11-01

The X-linked hypohidrotic ectodermal dysplasia (EDA) locus has been previously localized to the subchromosomal region Xq11-q21.1. The authors have extended previous linkage studies and analyzed linkage between the EDA locus and 10 marker loci, including five new loci, in 41 families. Four of the marker loci showed no recombination with the EDA locus, and six other loci were also linked to the EDA locus with recombination fractions of .009-.075. Multipoint analysis gave support to the placement of the PGK1P1 locus proximal to the EDA locus and the DXS453 and PGK1 loci distal to EDA. Further ordering of the loci couldmore » be inferred from a human-rodent somatic cell hybrid derived from an affected female with EDA and an X;9 translocation and from studies of an affected male with EDA and a submicroscopic deletion. Three of the proximal marker loci, which showed no recombination with the EDA locus, when used in combination, were informative in 92% of females. The closely linked flanking polymorphic loci DXS339 and DXS453 had heterozygosites of 72% and 76%, respectively, and when used jointly, they were doubly informative in 52% of females. The human DXS732 locus was defined by a conserved mouse probe pcos169E/4 (DXCrc169 locus) that consegregates with the mouse tabby (Ta) locus, a potential homologue to the EDA locus. The absence of recombination between EDA and the DXSA732 locus lends support to the hypothesis that the DXCrc169 locus in the mouse and the DXS732 locus in humans may contain candidate sequences for the Ta and EDA genes, respectively. 36 refs., 1 fig., 5 tabs.« less

A Rhomboid Protease Gene Deletion Affects a Novel Oligosaccharide N-Linked to the S-layer Glycoprotein of Haloferax volcanii*

PubMed Central

Parente, Juliana; Casabuono, Adriana; Ferrari, María Celeste; Paggi, Roberto Alejandro; De Castro, Rosana Esther; Couto, Alicia Susana; Giménez, María Inés

2014-01-01

Rhomboid proteases occur in all domains of life; however, their physiological role is not completely understood, and nothing is known of the biology of these enzymes in Archaea. One of the two rhomboid homologs of Haloferax volcanii (RhoII) is fused to a zinc finger domain. Chromosomal deletion of rhoII was successful, indicating that this gene is not essential for this organism; however, the mutant strain (MIG1) showed reduced motility and increased sensitivity to novobiocin. Membrane preparations of MIG1 were enriched in two glycoproteins, identified as the S-layer glycoprotein and an ABC transporter component. The H. volcanii S-layer glycoprotein has been extensively used as a model to study haloarchaeal protein N-glycosylation. HPLC analysis of oligosaccharides released from the S-layer glycoprotein after PNGase treatment revealed that MIG1 was enriched in species with lower retention times than those derived from the parent strain. Mass spectrometry analysis showed that the wild type glycoprotein released a novel oligosaccharide species corresponding to GlcNAc-GlcNAc(Hex)2-(SQ-Hex)6 in contrast to the mutant protein, which contained the shorter form GlcNAc2(Hex)2-SQ-Hex-SQ. A glycoproteomics approach of the wild type glycopeptide fraction revealed Asn-732 peptide fragments linked to the sulfoquinovose-containing oligosaccharide. This work describes a novel N-linked oligosaccharide containing a repeating SQ-Hex unit bound to Asn-732 of the H. volcanii S-layer glycoprotein, a position that had not been reported as glycosylated. Furthermore, this study provides the first insight on the biological role of rhomboid proteases in Archaea, suggesting a link between protein glycosylation and this protease family. PMID:24596091

Morphology of a submerged insular shelves in the West Alboran Basin.

NASA Astrophysics Data System (ADS)

Lafosse, Manfred; Le Roy, Pascal; Gorini, Christian; Rabineau, Marina; d'Acremont, Elia; Rabaute, Alain

2017-04-01

The dynamic of the seafloor in the Western Mediterranean Sea reflects the variety of the natural processes shaping it. Each of the sub-surface features is the result of tectonic, sedimentary and oceanic processes and eustatic sea-level variations. This study is focused on the morphology of three flat bathymetric highs and on the continental shelf in the Alboran Sea that show a variety of detailed seabed features that we attribute to a combination of present-day Mediterranean water mass flows, Quaternary active folding and faulting, differential erosion linked to relative-sea-level variation and local hydrodynamic. Swath bathymetry and reflectivity data, 2D seismic lines of multiple resolutions (12 channels, SPARKER source, and TOPAS seismic lines) have been acquired during three successive cruises: the MARLBORO-1 (2011), the MARLBORO-2 (2012) and the SARAS (2012) surveys. Our study deciphers the seabed structure of the banks with morphometric measurements (slope gradient, plan curvature, and topographic index) and correlates these structures to the stratigraphy of surrounding shelf. We show that the competition between active folding of the Miocene units and the erosion linked to the late Quaternary lowstands is creates the topography of the banks. The elevations of the flat surfaces measured on the banks are close to -110m and -80m. They are interpreted as submerged depositional surfaces linked to glacial and post-glacial deposit and wave-ravinement erosional surfaces as observed in other Mediterranean continental shelves. The analysis of the altitudinal spacing of these marine terraces indicates a spatial pattern with varying uplift rates. Furthermore, the characterization of sub-aqueous dune patterns locally linked to potential cold carbonate seamount could reflect the influence of water-masses current on the stratigraphic organization.

A rhomboid protease gene deletion affects a novel oligosaccharide N-linked to the S-layer glycoprotein of Haloferax volcanii.

PubMed

Parente, Juliana; Casabuono, Adriana; Ferrari, María Celeste; Paggi, Roberto Alejandro; De Castro, Rosana Esther; Couto, Alicia Susana; Giménez, María Inés

2014-04-18

Rhomboid proteases occur in all domains of life; however, their physiological role is not completely understood, and nothing is known of the biology of these enzymes in Archaea. One of the two rhomboid homologs of Haloferax volcanii (RhoII) is fused to a zinc finger domain. Chromosomal deletion of rhoII was successful, indicating that this gene is not essential for this organism; however, the mutant strain (MIG1) showed reduced motility and increased sensitivity to novobiocin. Membrane preparations of MIG1 were enriched in two glycoproteins, identified as the S-layer glycoprotein and an ABC transporter component. The H. volcanii S-layer glycoprotein has been extensively used as a model to study haloarchaeal protein N-glycosylation. HPLC analysis of oligosaccharides released from the S-layer glycoprotein after PNGase treatment revealed that MIG1 was enriched in species with lower retention times than those derived from the parent strain. Mass spectrometry analysis showed that the wild type glycoprotein released a novel oligosaccharide species corresponding to GlcNAc-GlcNAc(Hex)2-(SQ-Hex)6 in contrast to the mutant protein, which contained the shorter form GlcNAc2(Hex)2-SQ-Hex-SQ. A glycoproteomics approach of the wild type glycopeptide fraction revealed Asn-732 peptide fragments linked to the sulfoquinovose-containing oligosaccharide. This work describes a novel N-linked oligosaccharide containing a repeating SQ-Hex unit bound to Asn-732 of the H. volcanii S-layer glycoprotein, a position that had not been reported as glycosylated. Furthermore, this study provides the first insight on the biological role of rhomboid proteases in Archaea, suggesting a link between protein glycosylation and this protease family.

Comparison of linkage analysis methods for genome-wide scanning of extended pedigrees, with application to the TG/HDL-C ratio in the Framingham Heart Study

PubMed Central

Horne, Benjamin D; Malhotra, Alka; Camp, Nicola J

2003-01-01

Background High triglycerides (TG) and low high-density lipoprotein cholesterol (HDL-C) jointly increase coronary disease risk. We performed linkage analysis for TG/HDL-C ratio in the Framingham Heart Study data as a quantitative trait, using methods implemented in LINKAGE, GENEHUNTER (GH), MCLINK, and SOLAR. Results were compared to each other and to those from a previous evaluation using SOLAR for TG/HDL-C ratio on this sample. We also investigated linked pedigrees in each region using by-pedigree analysis. Results Fourteen regions with at least suggestive linkage evidence were identified, including some that may increase and some that may decrease coronary risk. Ten of the 14 regions were identified by more than one analysis, and several of these regions were not previously detected. The best regions identified for each method were on chromosomes 2 (LOD = 2.29, MCLINK), 5 (LOD = 2.65, GH), 7 (LOD = 2.67, SOLAR), and 22 (LOD = 3.37, LINKAGE). By-pedigree multi-point LOD values in MCLINK showed linked pedigrees for all five regions, ranging from 3 linked pedigrees (chromosome 5) to 14 linked pedigrees (chromosome 7), and suggested localizations of between 9 cM and 27 cM in size. Conclusion Reasonable concordance was found across analysis methods. No single method identified all regions, either by full sample LOD or with by-pedigree analysis. Concordance across methods appeared better at the pedigree level, with many regions showing by-pedigree support in MCLINK when no evidence was observed in the full sample. Thus, investigating by-pedigree linkage evidence may provide a useful tool for evaluating linkage regions. PMID:14975161

Comparison of linkage analysis methods for genome-wide scanning of extended pedigrees, with application to the TG/HDL-C ratio in the Framingham Heart Study.

PubMed

Horne, Benjamin D; Malhotra, Alka; Camp, Nicola J

2003-12-31

High triglycerides (TG) and low high-density lipoprotein cholesterol (HDL-C) jointly increase coronary disease risk. We performed linkage analysis for TG/HDL-C ratio in the Framingham Heart Study data as a quantitative trait, using methods implemented in LINKAGE, GENEHUNTER (GH), MCLINK, and SOLAR. Results were compared to each other and to those from a previous evaluation using SOLAR for TG/HDL-C ratio on this sample. We also investigated linked pedigrees in each region using by-pedigree analysis. Fourteen regions with at least suggestive linkage evidence were identified, including some that may increase and some that may decrease coronary risk. Ten of the 14 regions were identified by more than one analysis, and several of these regions were not previously detected. The best regions identified for each method were on chromosomes 2 (LOD = 2.29, MCLINK), 5 (LOD = 2.65, GH), 7 (LOD = 2.67, SOLAR), and 22 (LOD = 3.37, LINKAGE). By-pedigree multi-point LOD values in MCLINK showed linked pedigrees for all five regions, ranging from 3 linked pedigrees (chromosome 5) to 14 linked pedigrees (chromosome 7), and suggested localizations of between 9 cM and 27 cM in size. Reasonable concordance was found across analysis methods. No single method identified all regions, either by full sample LOD or with by-pedigree analysis. Concordance across methods appeared better at the pedigree level, with many regions showing by-pedigree support in MCLINK when no evidence was observed in the full sample. Thus, investigating by-pedigree linkage evidence may provide a useful tool for evaluating linkage regions.

Whey protein isolate with improved film properties through cross-linking catalyzed by small laccase from Streptomyces coelicolor.

PubMed

Quan, Wei; Zhang, Chong; Zheng, Meixia; Lu, Zhaoxin; Lu, Fengxia

2018-08-01

The effects of small laccase (SLAC) from Streptomyces coelicolor on the properties of whey protein isolate (WPI) films were studied. WPI was catalyze by SLAC without phenolic acid assistance. Particle size distribution results showed that some complexes with higher relative molecular weight formed in WPI samples treated with SLAC. The content of α-helixes decreased while those of β-sheets and random coils increased following SLAC treatment according to circular dichroism results. Fourier transform infrared spectral analysis suggested that some conformational changes occurred in WPI following SLAC treatment. Analysis of WPI films prepared by casting after SLAC treatment indicated that their film properties were all improved, including mechanical properties, solubility, water vapor, oxygen and carbon dioxide barrier properties, film color, light transmission, transparency and thermal properties. Compared with that of the control film, some obvious differences in the morphology of the WPI films were observed following SLAC treatment. This report demonstrates that laccase can directly catalyze protein cross-linking, which may be useful to improve the performance of protein films. In this study, SLAC was applied to WPI edible film during the film-making process. The results showed that SLAC can catalyze WPI cross-linking without phenolic acid assistance, and WPI film properties were improved after SLAC treatment. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Supporting awareness through collaborative brushing and linking of tabular data.

PubMed

Hajizadeh, Amir Hossein; Tory, Melanie; Leung, Rock

2013-12-01

Maintaining an awareness of collaborators' actions is critical during collaborative work, including during collaborative visualization activities. Particularly when collaborators are located at a distance, it is important to know what everyone is working on in order to avoid duplication of effort, share relevant results in a timely manner and build upon each other's results. Can a person's brushing actions provide an indication of their queries and interests in a data set? Can these actions be revealed to a collaborator without substantially disrupting their own independent work? We designed a study to answer these questions in the context of distributed collaborative visualization of tabular data. Participants in our study worked independently to answer questions about a tabular data set, while simultaneously viewing brushing actions of a fictitious collaborator, shown directly within a shared workspace. We compared three methods of presenting the collaborator's actions: brushing & linking (i.e. highlighting exactly what the collaborator would see), selection (i.e. showing only a selected item), and persistent selection (i.e. showing only selected items but having them persist for some time). Our results demonstrated that persistent selection enabled some awareness of the collaborator's activities while causing minimal interference with independent work. Other techniques were less effective at providing awareness, and brushing & linking caused substantial interference. These findings suggest promise for the idea of exploiting natural brushing actions to provide awareness in collaborative work.

Leaf Photosynthetic Rate of Tropical Ferns Is Evolutionarily Linked to Water Transport Capacity

PubMed Central

Cao, Kun-Fang; Hu, Hong; Zhang, Jiao-Lin

2014-01-01

Ferns usually have relatively lower photosynthetic potential than angiosperms. However, it is unclear whether low photosynthetic potential of ferns is linked to leaf water supply. We hypothesized that there is an evolutionary association of leaf water transport capacity with photosynthesis and stomatal density in ferns. In the present study, a series of functional traits relating to leaf anatomy, hydraulics and physiology were assessed in 19 terrestrial and 11 epiphytic ferns in a common garden, and analyzed by a comparative phylogenetics method. Compared with epiphytic ferns, terrestrial ferns had higher vein density (Dvein), stomatal density (SD), stomatal conductance (gs), and photosynthetic capacity (Amax), but lower values for lower epidermal thickness (LET) and leaf thickness (LT). Across species, all traits varied significantly, but only stomatal length (SL) showed strong phylogenetic conservatism. Amax was positively correlated with Dvein and gs with and without phylogenetic corrections. SD correlated positively with Amax, Dvein and gs, with the correlation between SD and Dvein being significant after phylogenetic correction. Leaf water content showed significant correlations with LET, LT, and mesophyll thickness. Our results provide evidence that Amax of the studied ferns is linked to leaf water transport capacity, and there was an evolutionary association between water supply and demand in ferns. These findings add new insights into the evolutionary correlations among traits involving carbon and water economy in ferns. PMID:24416265

Feeding ecology of Ammothella longipes (Arthropoda: Pycnogonida) in the Mediterranean Sea: A fatty acid biomarker approach

NASA Astrophysics Data System (ADS)

Soler-Membrives, Anna; Rossi, Sergio; Munilla, Tomás

2011-05-01

Fatty acid analysis has proved valuable in determining seasonal trophic links and the feeding behavior in organisms in which these diet and trophic links cannot be inferred from stomach content analyses. Seasonal variations in total free fatty acid content (TFFA) and fatty acid composition of seston (<250 μm), the brown macroalgae Stypocaulon spp., polychaetes (Nereididae) and the pycnogonid Ammothella longipes have been used to establish their trophic links, with particular focus on seasonality and feeding ecology of A. longipes. Samples were collected in a coastal environment (NW Mediterranean Sea) at 7-10 m depth, in five different periods (August and October 2008, February, June and September 2009). Seston and Stypocaulon spp. samples did not show significant seasonal variations in TFFA content, while nereids showed a significant variation. Analysis of fatty acid profile showed high similarities of fatty acid composition between seston and Stypocaulon spp. Nereids were closer to seston and Stypocaulon spp. than A. longipes, which seemed to follow a seasonal trend. The results of this study reveal that A. longipes may change its feeding behavior depending on the season and available food. This pycnogonid species appears to be carnivore during spring and early summer but seems to feed on detritus when availability of prey diminishes during winter. Notable high amounts of odd-chain fatty acids are found in summer-autumn for this species, which may come from bacteria acquired from the detrital diet or from de novo biosynthesis from propionate. The results obtained provide new and valuable data on the understudied feeding biology of pycnogonids in general, and contribute to the understanding of their functioning of Mediterranean shallow oligotrophic systems and their trophic links.

Biocompatibility of NGF-grafted GTG membranes for peripheral nerve repair using cultured Schwann cells.

PubMed

Chen, Pei-Ru; Chen, Ming-Hong; Sun, Jui-Sheng; Chen, Mei-Hsiu; Tsai, Chien-Chen; Lin, Feng-Huei

2004-11-01

We previously developed a biodegradable composite with potentially good biocompatibility composed by tricalcium phosphate and gluataraldehyde cross-linking gelatin (GTG) with good mechanical property feasible for surgical manipulation. The purpose of this study was to evaluate the feasibility of immobilizing nerve growth factor (NGF) onto the composite (GTG) with carbodiimide (GEN composite). Cultured Schwann cells were seeded onto the GTG and GEN composites. For comparison, GTG membrane soaked in NGF solution without carbodiimide (GN composite) as cross-linking agent was also used to culture Schwann cells. Cell morphology was observed by a scanning electron microscope. Cell survival, cytotoxicity and cellular metabolism on the NGF-grafted GTG membrane were assessed quantitatively in terms of cell protein content, leakage of cytosolic lactate dehydrogenase (LDH) activity and by the well-established MTT assay, respectively. The result of LDH study did not show significant difference among GTG, NGF-modified GTG and control group. This indicated that GTG composite, whether cross-linking with NGF or not, has little cytotoxic effect. Comparing the protein content and MTT assay among GEN, GN composite and control group, the data confirmed more attachment of Schwann cells on GEN composite. Although GTG cross-linking with NGF did not promote Schwann cell proliferation, the techniques we used in this study provided a method to fabricate a novel biomaterial incorporation of Schwann cells and covalently immobilized NGF.

Estimation of carbon dioxide emissions per urban center link unit using data collected by the Advanced Traffic Information System in Daejeon, Korea

NASA Astrophysics Data System (ADS)

Ryu, B. Y.; Jung, H. J.; Bae, S. H.; Choi, C. U.

2013-12-01

CO2 emissions on roads in urban centers substantially affect global warming. It is important to quantify CO2 emissions in terms of the link unit in order to reduce these emissions on the roads. Therefore, in this study, we utilized real-time traffic data and attempted to develop a methodology for estimating CO2 emissions per link unit. Because of the recent development of the vehicle-to-infrastructure (V2I) communication technology, data from probe vehicles (PVs) can be collected and speed per link unit can be calculated. Among the existing emission calculation methodologies, mesoscale modeling, which is a representative modeling measurement technique, requires speed and traffic data per link unit. As it is not feasible to install fixed detectors at every link for traffic data collection, in this study, we developed a model for traffic volume estimation by utilizing the number of PVs that can be additionally collected when the PV data are collected. Multiple linear regression and an artificial neural network (ANN) were used for estimating the traffic volume. The independent variables and input data for each model are the number of PVs, travel time index (TTI), the number of lanes, and time slots. The result from the traffic volume estimate model shows that the mean absolute percentage error (MAPE) of the ANN is 18.67%, thus proving that it is more effective. The ANN-based traffic volume estimation served as the basis for the calculation of emissions per link unit. The daily average emissions for Daejeon, where this study was based, were 2210.19 ton/day. By vehicle type, passenger cars accounted for 71.28% of the total emissions. By road, Gyeryongro emitted 125.48 ton/day, accounting for 5.68% of the total emission, the highest percentage of all roads. In terms of emissions per kilometer, Hanbatdaero had the highest emission volume, with 7.26 ton/day/km on average. This study proves that real-time traffic data allow an emissions estimate in terms of the link unit. Furthermore, an analysis of CO2 emissions can support traffic management to make decisions related to the reduction of carbon emissions.

Can Birds Perceive Rhythmic Patterns? A Review and Experiments on a Songbird and a Parrot Species

PubMed Central

ten Cate, Carel; Spierings, Michelle; Hubert, Jeroen; Honing, Henkjan

2016-01-01

While humans can easily entrain their behavior with the beat in music, this ability is rare among animals. Yet, comparative studies in non-human species are needed if we want to understand how and why this ability evolved. Entrainment requires two abilities: (1) recognizing the regularity in the auditory stimulus and (2) the ability to adjust the own motor output to the perceived pattern. It has been suggested that beat perception and entrainment are linked to the ability for vocal learning. The presence of some bird species showing beat induction, and also the existence of vocal learning as well as vocal non-learning bird taxa, make them relevant models for comparative research on rhythm perception and its link to vocal learning. Also, some bird vocalizations show strong regularity in rhythmic structure, suggesting that birds might perceive rhythmic structures. In this paper we review the available experimental evidence for the perception of regularity and rhythms by birds, like the ability to distinguish regular from irregular stimuli over tempo transformations and report data from new experiments. While some species show a limited ability to detect regularity, most evidence suggests that birds attend primarily to absolute and not relative timing of patterns and to local features of stimuli. We conclude that, apart from some large parrot species, there is limited evidence for beat and regularity perception among birds and that the link to vocal learning is unclear. We next report the new experiments in which zebra finches and budgerigars (both vocal learners) were first trained to distinguish a regular from an irregular pattern of beats and then tested on various tempo transformations of these stimuli. The results showed that both species reduced the discrimination after tempo transformations. This suggests that, as was found in earlier studies, they attended mainly to local temporal features of the stimuli, and not to their overall regularity. However, some individuals of both species showed an additional sensitivity to the more global pattern if some local features were left unchanged. Altogether our study indicates both between and within species variation, in which birds attend to a mixture of local and to global rhythmic features. PMID:27242635

Automated Assignment of MS/MS Cleavable Cross-Links in Protein 3D-Structure Analysis

NASA Astrophysics Data System (ADS)

Götze, Michael; Pettelkau, Jens; Fritzsche, Romy; Ihling, Christian H.; Schäfer, Mathias; Sinz, Andrea

2015-01-01

CID-MS/MS cleavable cross-linkers hold an enormous potential for an automated analysis of cross-linked products, which is essential for conducting structural proteomics studies. The created characteristic fragment ion patterns can easily be used for an automated assignment and discrimination of cross-linked products. To date, there are only a few software solutions available that make use of these properties, but none allows for an automated analysis of cleavable cross-linked products. The MeroX software fills this gap and presents a powerful tool for protein 3D-structure analysis in combination with MS/MS cleavable cross-linkers. We show that MeroX allows an automatic screening of characteristic fragment ions, considering static and variable peptide modifications, and effectively scores different types of cross-links. No manual input is required for a correct assignment of cross-links and false discovery rates are calculated. The self-explanatory graphical user interface of MeroX provides easy access for an automated cross-link search platform that is compatible with commonly used data file formats, enabling analysis of data originating from different instruments. The combination of an MS/MS cleavable cross-linker with a dedicated software tool for data analysis provides an automated workflow for 3D-structure analysis of proteins. MeroX is available at www.StavroX.com .

Rainfall estimation using microwave links. Results from an experimental setup in Luxembourg

NASA Astrophysics Data System (ADS)

Fenicia, Fabrizio; Matgen, Patrick; Pfister, Laurent

2010-05-01

Microwave links represent a valid alternative to traditional rainfall estimation methods. They are commonly used in mobile phone communication, and they constitute built-in widely distributed networks. Due to their ability of providing high temporal and spatial resolution measurements, their use is particularly suitable in urban settings. We here show results from an experimental setup in Luxembourg City, where two dual frequency links have been installed. The links cover a distance of about 4km, and measure power attenuation at 1 min. timestep. The links have been equipped with several recording raingauges, which measure rainfall in real-time communicating through a wireless connection. This set-up has been used to analyze in detail the mapping between attenuation and rainfall intensity, and gain insights into the potential accuracy of these instruments. In addition, we investigated the relation between rainfall and discharge response of the urban area of Luxembourg, which shows the potential utility of high frequency rainfall measurements for urban environments.

The role of social relationships in the link between olfactory dysfunction and mortality.

PubMed

Leschak, Carrianne J; Eisenberger, Naomi I

2018-01-01

Recent work suggests that olfactory dysfunction is a strong predictor of five-year mortality in older adults. Based on past work showing: 1) that olfactory dysfunction impairs social functioning and 2) that social ties are linked with mortality, the current work explored whether impairments in social life mediated the relationship between olfactory dysfunction and mortality. Additionally, based on work showing gender differences in the social consequences of olfactory dysfunction, gender was assessed as a potential moderator of this association. Social network size mediated the olfactory-mortality link for females. To probe what feature of social networks was driving this effect, we investigated two subcomponents of social life: emotional closeness (e.g., perceived social support, loneliness) and physical closeness (e.g., physical contact, in-person socializing with others). Physical closeness significantly mediated the olfactory-mortality link for females, even after controlling for social network size. Emotional closeness did not mediate this link. Possible mechanisms underlying this relationship are discussed.

Dexras1 links glucocorticoids to insulin-like growth factor-1 signaling in adipogenesis

PubMed Central

Kim, Hyo Jung; Cha, Jiyoung Y.; Seok, Jo Woon; Choi, Yoonjeong; Yoon, Bo Kyung; Choi, Hyeonjin; Yu, Jung Hwan; Song, Su Jin; Kim, Ara; Lee, Hyemin; Kim, Daeun; Han, Ji Yoon; Kim, Jae-woo

2016-01-01

Glucocorticoids are associated with obesity, but the underlying mechanism by which they function remains poorly understood. Previously, we showed that small G protein Dexras1 is expressed by glucocorticoids and leads to adipocyte differentiation. In this study, we explored the mechanism by which Dexras1 mediates adipogenesis and show a link to the insulin-like growth factor-1 (IGF-1) signaling pathway. Without Dexras1, the activation of MAPK and subsequent phosphorylation of CCAAT/enhancer binding protein β (C/EBPβ) is abolished, thereby inhibiting mitotic clonal expansion and further adipocyte differentiation. Dexras1 translocates to the plasma membrane upon insulin or IGF-1 treatment, for which the unique C-terminal domain (amino acids 223–276) is essential. Dexras1-dependent MAPK activation is selectively involved in the IGF-1 signaling, because another Ras protein, H-ras localized to the plasma membrane independently of insulin treatment. Moreover, neither epidermal growth factor nor other cell types shows Dexras1-dependent MAPK activation, indicating the importance of Dexras1 in IGF-1 signaling in adipogenesis. Dexras1 interacts with Shc and Raf, indicating that Dexras1-induced activation of MAPK is largely dependent on the Shc-Grb2-Raf complex. These results suggest that Dexras1 is a critical mediator of the IGF-1 signal to activate MAPK, linking glucocorticoid signaling to IGF-1 signaling in adipogenesis. PMID:27345868

Recent gene-capture on the UV sex chromosomes of the moss Ceratodon purpureus.

PubMed

McDaniel, Stuart F; Neubig, Kurt M; Payton, Adam C; Quatrano, Ralph S; Cove, David J

2013-10-01

Sex chromosomes evolve from ordinary autosomes through the expansion and subsequent degeneration of a region of suppressed recombination that is inherited through one sex. Here we investigate the relative timing of these processes in the UV sex chromosomes of the moss Ceratodon purpureus using molecular population genetic analyses of eight newly discovered sex-linked loci. In this system, recombination is suppressed on both the female-transmitted (U) sex chromosome and the male-transmitted (V) chromosome. Genes on both chromosomes therefore should show the deleterious effects of suppressed recombination and sex-limited transmission, while purifying selection should maintain homologs of genes essential for both sexes on both sex chromosomes. Based on analyses of eight sex-linked loci, we show that the nonrecombining portions of the U and V chromosomes expanded in at least two events (~0.6-1.3 MYA and ~2.8-3.5 MYA), after the divergence of C. purpureus from its dioecious sister species, Trichodon cylindricus and Cheilothela chloropus. Both U- and V-linked copies showed reduced nucleotide diversity and limited population structure, compared to autosomal loci, suggesting that the sex chromosomes experienced more recent selective sweeps that the autosomes. Collectively these results highlight the dynamic nature of gene composition and molecular evolution on nonrecombining portions of the U and V sex chromosomes. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

A neo-W chromosome in a tropical butterfly links colour pattern, male-killing, and speciation.

PubMed

Smith, David A S; Gordon, Ian J; Traut, Walther; Herren, Jeremy; Collins, Steve; Martins, Dino J; Saitoti, Kennedy; Ireri, Piera; Ffrench-Constant, Richard

2016-07-27

Sexually antagonistic selection can drive both the evolution of sex chromosomes and speciation itself. The tropical butterfly the African Queen, Danaus chrysippus, shows two such sexually antagonistic phenotypes, the first being sex-linked colour pattern, the second, susceptibility to a male-killing, maternally inherited mollicute, Spiroplasma ixodeti, which causes approximately 100% mortality in male eggs and first instar larvae. Importantly, this mortality is not affected by the infection status of the male parent and the horizontal transmission of Spiroplasma is unknown. In East Africa, male-killing of the Queen is prevalent in a narrow hybrid zone centred on Nairobi. This hybrid zone separates otherwise allopatric subspecies with different colour patterns. Here we show that a neo-W chromosome, a fusion between the W (female) chromosome and an autosome that controls both colour pattern and male-killing, links the two phenotypes thereby driving speciation across the hybrid zone. Studies of the population genetics of the neo-W around Nairobi show that the interaction between colour pattern and male-killer susceptibility restricts gene flow between two subspecies of D. chrysippus Our results demonstrate how a complex interplay between sex, colour pattern, male-killing, and a neo-W chromosome, has set up a genetic 'sink' that keeps the two subspecies apart. The association between the neo-W and male-killing thus provides a 'smoking gun' for an ongoing speciation process. © 2016 The Authors.

Effect of Rubber Polarity on Cluster Formation in Rubbers Cross-Linked with Diels–Alder Chemistry

PubMed Central

2017-01-01

Diels–Alder chemistry has been used for the thermoreversible cross-linking of furan-functionalized ethylene/propylene (EPM) and ethylene/vinyl acetate (EVM) rubbers. Both furan-functionalized elastomers were successfully cross-linked with bismaleimide to yield products with a similar cross-link density. NMR relaxometry and SAXS measurements both show that the apolar EPM-g-furan precursor contains phase-separated polar clusters and that cross-linking with polar bismaleimide occurs in these clusters. The heterogeneously cross-linked network of EPM-g-furan contrasts with the homogeneous network in the polar EVM-g-furan. The heterogeneous character of the cross-links in EPM-g-furan results in a relatively high Young’s modulus, whereas the more uniform cross-linking in EVM-g-furan results in a higher tensile strength and elongation at break. PMID:29213149

Relationships of Attitudes toward Homework and Time Spent on Homework to Course Outcomes: The Case of Foreign Language Learning

ERIC Educational Resources Information Center

Chang, Charles B.; Wall, Daniel; Tare, Medha; Golonka, Ewa; Vatz, Karen

2014-01-01

In previous studies of homework in core academic subjects, positive student attitudes toward homework were linked to higher achievement, whereas time spent on homework showed an inconsistent relationship with achievement. This study examined the generalizability of these findings to foreign language learning by analyzing 2,342 adult students'…

One of the Boys: Constructions of Disengagement and Criteria for Being a Successful Student

ERIC Educational Resources Information Center

Grønborg, Lisbeth

2013-01-01

The article discusses how a peer group culture in the school setting, embedded in conflicting fields of work and education, co-constructs student disengagement. Disengagement is traditionally linked with dropout and engagement with completion, but the study shows that this relation is not so linear. The data are based on a field study, where the…

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

Rivedal, Edgar; Leithe, Edward

Benzene is used at large volumes in many different human activities. Hematotoxicity and cancer-causation as a result of benzene exposure was recognized many years ago, but the mechanisms involved remain unclear. Aberrant regulation of gap junction intercellular communication (GJIC) has been linked to both cancer induction and interference with normal hematopoietic development. We have previously suggested that inhibition of GJIC may play a role in benzene toxicity since benzene metabolites were found to block GJIC, the ring-opened trans,trans-muconaldehyde (MUC) being the most potent metabolite. In the present work we have studied the molecular mechanisms underlying the MUC-induced inhibition of gapmore » junctional communication. We show that MUC induces cross-linking of the gap junction protein connexin43 and that this is likely to be responsible for the induced inhibition of GJIC, as well as the loss of connexin43 observed in Western blots. We also show that glutaraldehyde possesses similar effects as MUC, and we compare the effects to that of formaldehyde. The fact that glutaraldehyde and formaldehyde have been associated with induction of leukemia as well as disturbance of hematopoiesis, strengthens the possible link between the effect of MUC on gap junctions, and the toxic effects of benzene.« less

Oil type and cross-linking influence growth of Aureobasidium melanogenum on vegetable oils as a single carbon source.

PubMed

Peeters, Loes H M; Huinink, Hendrik P; Voogt, Benjamin; Adan, Olaf C G

2018-03-12

Aureobasidium melanogenum is the main fungus found in a spontaneously formed biofilm on a oil-treated wood. This dark colored biofilm functions as a protective coating. To better understand biofilm formation, in this study A. melanogenum was cultured on olive oil and raw linseed oil. Metabolic activity and oil conversion were measured. The results show that A. melanogenum is able to grow on linseed oil and olive oil as a single carbon source. The fungus produces the enzyme lipase to convert the oil into fatty acids and glycerol. Metabolic activity and oil conversion were equal on linseed oil and olive oil. The fungus was not able to grow on severe cross-linked linseed oil, meaning that the degree of cross-linking of the oil is important for growth of A. melanogenum. Dark coloring of the colony was seen on linseed oil, which might be a stress response on the presence of autoxidation products in linseed oil. The colony on olive oil showed delayed melanin production indicating an inhibitory effect of olive oil on melanin production. © 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Tebufenozide resistance is associated with sex-linked inheritance in Plutella xylostella.

PubMed

Cao, Guang-Chun; Han, Zhao-Jun

2015-04-01

The diamondback moth (DBM), Plutella xylostella (L.), is a major pest of cruciferous crops. Tebufenozide, a novel nonsteroidal ecdysone agonist, exhibits good efficacy and has played an increasingly important role in the control of Lepidopteran pests in China. For its resistance management, the genetic basis of tebufenozide resistance was studied using a laboratory selected resistant strain of DBM (resistant ratio, RR = 268). A series of crosses with laboratory susceptible and resistant strains revealed that tebufenozide resistance in this pest was partially biased toward female heredity, with a large difference in RR for F1 (RR = 29) and rF1 progeny (RR = 147). The dominance calculated for these 2 cross progeny was -0.788 and 0.09, respectively. Further analysis showed that the susceptible male and female larvae were similar in their sensitivity to tebufenozide, but the resistant female larvae showed significantly higher resistance than the resistant male larvae. The heredity of tebufenozide resistance in DBM might be linked with the W sex chromosome, which suggested that DBM has the ability to develop high levels of resistance to tebufenozide. This is the first report of sex-linked inheritance of tebufenozide resistance in P. xylostella (L.). © 2013 Institute of Zoology, Chinese Academy of Sciences.

Enzyme-linked, aptamer-based, competitive biolayer interferometry biosensor for palytoxin.

PubMed

Gao, Shunxiang; Zheng, Xin; Hu, Bo; Sun, Mingjuan; Wu, Jihong; Jiao, Binghua; Wang, Lianghua

2017-03-15

In this study, we coupled biolayer interferometry (BLI) with competitive binding assay through an enzyme-linked aptamer and developed a real-time, ultra-sensitive, rapid quantitative method for detection of the marine biotoxin palytoxin. Horseradish peroxidase-labeled aptamers were used as biorecognition receptors to competitively bind with palytoxin, which was immobilized on the biosensor surface. The palytoxin: horseradish peroxidase-aptamer complex was then submerged in a 3,3'-diaminobenzidine solution, which resulted in formation of a precipitated polymeric product directly on the biosensor surface and a large change in the optical thickness of the biosensor layer. This change could obviously shift the interference pattern and generate a response profile on the BLI biosensor. The biosensor showed a broad linear range for palytoxin (200-700pg/mL) with a low detection limit (0.04pg/mL). Moreover, the biosensor was applied to the detection of palytoxin in spiked extracts and showed a high degree of selectivity for palytoxin, good reproducibility, and stability. This enzyme-linked, aptamer-based, competitive BLI biosensor offers a promising method for rapid and sensitive detection of palytoxin and other analytes. Copyright © 2016 Elsevier B.V. All rights reserved.

Recyclable cross-linked anion exchange membrane for alkaline fuel cell application

NASA Astrophysics Data System (ADS)

Hou, Jianqiu; Liu, Yazhi; Ge, Qianqian; Yang, Zhengjin; Wu, Liang; Xu, Tongwen

2018-01-01

Cross-linking can effectively solve the conductivity-swelling dilemma in anion exchange membranes (AEMs) but will generate solid wastes. To address this, we developed an AEM cross-linked via disulfide bonds, bearing quaternary ammonium groups, which can be easily recycled. The membrane (RC-QPPO) with IEC of 1.78 mmol g-1, when cross-linked, showed enhanced mechanical properties and good hydroxide conductivity (24.6 mS cm-1 at 30 °C). Even at higher IEC value (2.13 mmol g-1), it still has low water uptake, low swelling ratio and delivers a peak power density of 150 mW cm-2 at 65 °C. Exploiting the formation of disulfide bonds from -SH groups, the membrane can be readily cross-linked in alkaline condition and recycled by reversibly breaking disulfide bonds with dithiothreitol (DTT). The recycled membrane solution can be directly utilized to cast a brand-new AEM. By washing away the residual DTT with water and exposure to air, it can be cross-linked again and this process is repeatable. During the recycling and cross-linking processes, the membrane showed a slight IEC decrease of 5% due to functional group degradation. The strategy presented here is promising in enhancing AEM properties and reducing the impact of artificial polymers on the environment.

Link prediction based on local community properties

NASA Astrophysics Data System (ADS)

Yang, Xu-Hua; Zhang, Hai-Feng; Ling, Fei; Cheng, Zhi; Weng, Guo-Qing; Huang, Yu-Jiao

2016-09-01

The link prediction algorithm is one of the key technologies to reveal the inherent rule of network evolution. This paper proposes a novel link prediction algorithm based on the properties of the local community, which is composed of the common neighbor nodes of any two nodes in the network and the links between these nodes. By referring to the node degree and the condition of assortativity or disassortativity in a network, we comprehensively consider the effect of the shortest path and edge clustering coefficient within the local community on node similarity. We numerically show the proposed method provide good link prediction results.