Structural Basis of Mitochondrial Transcription Initiation.

PubMed

Hillen, Hauke S; Morozov, Yaroslav I; Sarfallah, Azadeh; Temiakov, Dmitry; Cramer, Patrick

2017-11-16

Transcription in human mitochondria is driven by a single-subunit, factor-dependent RNA polymerase (mtRNAP). Despite its critical role in both expression and replication of the mitochondrial genome, transcription initiation by mtRNAP remains poorly understood. Here, we report crystal structures of human mitochondrial transcription initiation complexes assembled on both light and heavy strand promoters. The structures reveal how transcription factors TFAM and TFB2M assist mtRNAP to achieve promoter-dependent initiation. TFAM tethers the N-terminal region of mtRNAP to recruit the polymerase to the promoter whereas TFB2M induces structural changes in mtRNAP to enable promoter opening and trapping of the DNA non-template strand. Structural comparisons demonstrate that the initiation mechanism in mitochondria is distinct from that in the well-studied nuclear, bacterial, or bacteriophage transcription systems but that similarities are found on the topological and conceptual level. These results provide a framework for studying the regulation of gene expression and DNA replication in mitochondria. Copyright © 2017 Elsevier Inc. All rights reserved.

Network structure and concentration fluctuations in a series of elemental, binary, and tertiary liquids and glasses.

PubMed

Soper, Alan K

2010-10-13

Liquids and glasses continue to produce a lively debate about the nature of the disordered structure in these materials, and whether it is driven by longer range concentration or density fluctuations. One factor often lacking in these studies is an overview of a wide range of structures from which common features of and differences between materials can be identified. Here I examine the structure of a wide range of chain and network, elemental, binary and tertiary liquids and glasses, using available x-ray and neutron diffraction data and combining them with empirical potential structure refinement. Calculation of the Bhatia-Thornton number-number and concentration-concentration structure factors and distribution functions highlights common structural motifs that run through many of the series. It is found that the greatest structural overlap occurs where the nearest-neighbour and second-neighbour coordination numbers are similar for different materials. As these coordination numbers increase, so the structures undergo a sequence of characteristic changes involving increasingly bent bond angle distributions and increased packing fractions. In these regards liquid and amorphous phosphorus appear to be in a structural class of their own, combining both chain-like and network-like characteristics.

The internal structure of foster-parent completed SDQ for school-aged children

PubMed Central

Lehmann, Stine; Bøe, Tormod; Breivik, Kyrre

2017-01-01

Mental health problems are common in foster-children, and tools to measure the mental health of these children are needed. One candidate instrument is the Strengths and Difficulties Questionnaire (SDQ), a measure of child psychological adjustment that is increasingly being employed by Child Protection services. The aim of the current study was to examine the structural validity of the foster parent completed SDQ in a sample of 237 school aged foster children. Confirmatory factor analysis demonstrated an excellent fit of the foster parent completed SDQ data to a five-factor model (CFI = 0.96, RMSEA = 0.05, 90% CI [0.04, 0.06]), thus confirming the structural validity of the five-factor model for the parent-version of the SDQ in Norwegian foster children. Measurement invariance analyses indicated that boys had lower thresholds for fighting with or bullying other children than girls. Girls were on their side more likely to be rated as less popular than boys with a similar level of peer problems. PMID:28665965

The internal structure of foster-parent completed SDQ for school-aged children.

PubMed

Lehmann, Stine; Bøe, Tormod; Breivik, Kyrre

2017-01-01

Mental health problems are common in foster-children, and tools to measure the mental health of these children are needed. One candidate instrument is the Strengths and Difficulties Questionnaire (SDQ), a measure of child psychological adjustment that is increasingly being employed by Child Protection services. The aim of the current study was to examine the structural validity of the foster parent completed SDQ in a sample of 237 school aged foster children. Confirmatory factor analysis demonstrated an excellent fit of the foster parent completed SDQ data to a five-factor model (CFI = 0.96, RMSEA = 0.05, 90% CI [0.04, 0.06]), thus confirming the structural validity of the five-factor model for the parent-version of the SDQ in Norwegian foster children. Measurement invariance analyses indicated that boys had lower thresholds for fighting with or bullying other children than girls. Girls were on their side more likely to be rated as less popular than boys with a similar level of peer problems.

Resin blending for toughness in balloon films

NASA Technical Reports Server (NTRS)

Farr, M. P.; Harrison, I. R.

1993-01-01

The influence of chain architecture on toughness is examined by testing blends of HDPE with different types of low density PEs. The LDPE and LLDPE used have reported similar molecular weights, and densities. Two structural factors differentiate these polymers, long chain branching is peculiar to LDPE, and the short chain branching distribution of the two polymers are different. LDPE has branches which are evenly distributed among all chains. In contrast, the short chain branches in LLDPE are distributed heterogeneously. LLDPE and ULDPE have similar branch distributions but, ULDPE has a higher average number of branches per 1000 carbons and consequently a lower density. The effect which these structural differences have on mechanical properties can be used to investigate which parameters control toughness in PE materials.

Construct Validity of the Autism Impact Measure (AIM).

PubMed

Mazurek, Micah O; Carlson, Coleen; Baker-Ericzén, Mary; Butter, Eric; Norris, Megan; Kanne, Stephen

2018-01-17

The Autism Impact Measure (AIM) was designed to track incremental change in frequency and impact of core ASD symptoms. The current study examined the structural and convergent validity of the AIM in a large sample of children with ASD. The results of a series of exploratory and confirmatory factor analyses yielded a final model with five theoretically and empirically meaningful subdomains: Repetitive Behavior, Atypical Behavior, Communication, Social Reciprocity, and Peer Interaction. The final model showed very good fit both overall and for each of the five factors, indicating excellent structural validity. AIM subdomain scores were significantly correlated with measures of similar constructs across all five domains. The results provide further support for the psychometric properties of the AIM.

Mechanical behavior and shape optimization of lining structure for subsea tunnel excavated in weathered slot

NASA Astrophysics Data System (ADS)

Li, Peng-fei; Zhou, Xiao-jun

2015-12-01

Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the country rock that surrounds a tunnel, thereby lowering the arching effect and stratum stability of the structure. In this paper, the mechanical behavior and shape optimization of the lining structure for the Xiang'an tunnel excavated in weathered slots are examined. Eight cross sections with different geometric parameters are adopted to study the mechanical behavior and shape optimization of the lining structure. The hyperstatic reaction method is used through finite element analysis software ANSYS. The mechanical behavior of the lining structure is evidently affected by the geometric parameters of crosssectional shape. The minimum safety factor of the lining structure elements is set to be the objective function. The efficient tunnel shape to maximize the minimum safety factor is identified. The minimum safety factor increases significantly after optimization. The optimized cross section significantly improves the mechanical characteristics of the lining structure and effectively reduces its deformation. Force analyses of optimization process and program are conducted parametrically so that the method can be applied to the optimization design of other similar structures. The results obtained from this study enhance our understanding of the mechanical behavior of the lining structure for subsea tunnels. These results are also beneficial to the optimal design of lining structures in general.

High-resolution structure of TBP with TAF1 reveals anchoring patterns in transcriptional regulation

PubMed Central

Anandapadamanaban, Madhanagopal; Andresen, Cecilia; Helander, Sara; Ohyama, Yoshifumi; Siponen, Marina I.; Lundström, Patrik; Kokubo, Tetsuro; Ikura, Mitsuhiko; Moche, Martin; Sunnerhagen, Maria

2016-01-01

The general transcription factor TFIID provides a regulatory platform for transcription initiation. Here we present the crystal structure (1.97 Å) and NMR analysis of yeast TAF1 N-terminal domains TAND1 and TAND2 when bound to yeast TBP, together with mutational data. The yTAF1-TAND1, which in itself acts as a transcriptional activator, binds into the DNA-binding TBP concave surface by presenting similar anchor residues to TBP as E. coli Mot1 but from a distinct structural scaffold. Furthermore, we show how yTAF1-TAND2 employs an aromatic and acidic anchoring pattern to bind a conserved yTBP surface groove traversing the basic helix region, and we find highly similar TBP-binding motifs also presented by the structurally distinct TFIIA, Mot1 and Brf1 proteins. Our identification of these anchoring patterns, which can be easily disrupted or enhanced, provides compelling insight into the competitive multiprotein TBP interplay critical to transcriptional regulation. PMID:23851461

High-resolution structure of TBP with TAF1 reveals anchoring patterns in transcriptional regulation.

PubMed

Anandapadamanaban, Madhanagopal; Andresen, Cecilia; Helander, Sara; Ohyama, Yoshifumi; Siponen, Marina I; Lundström, Patrik; Kokubo, Tetsuro; Ikura, Mitsuhiko; Moche, Martin; Sunnerhagen, Maria

2013-08-01

The general transcription factor TFIID provides a regulatory platform for transcription initiation. Here we present the crystal structure (1.97 Å) and NMR analysis of yeast TAF1 N-terminal domains TAND1 and TAND2 bound to yeast TBP, together with mutational data. We find that yeast TAF1-TAND1, which in itself acts as a transcriptional activator, binds TBP's concave DNA-binding surface by presenting similar anchor residues to TBP as does Mot1 but from a distinct structural scaffold. Furthermore, we show how TAF1-TAND2 uses an aromatic and acidic anchoring pattern to bind a conserved TBP surface groove traversing the basic helix region, and we find highly similar TBP-binding motifs also presented by the structurally distinct TFIIA, Mot1 and Brf1 proteins. Our identification of these anchoring patterns, which can be easily disrupted or enhanced, provides insight into the competitive multiprotein TBP interplay critical to transcriptional regulation.

The Mannitol Operon Repressor MTIR belongs to a new class of transcription regulators in bacteria.

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

Tan, K.; Borovilos, M.; Zhou, M

2009-12-25

Many bacteria express phosphoenolpyruvate-dependent phosphotransferase systems (PTS). The mannitol-specific PTS catalyze the uptake and phosphorylation of d-mannitol. The uptake system comprises several genes encoded in the single operon. The expression of the mannitol operon is regulated by a proposed transcriptional factor, mannitol operon repressor (MtlR) that was first studied in Escherichia coli. Here we report the first crystal structures of MtlR from Vibrio parahemeolyticus (Vp-MtlR) and its homolog YggD protein from Shigella flexneri (Sf-YggD). MtlR and YggD belong to the same protein family (Pfam05068). Although Vp-MtlR and Sf-YggD share low sequence identity (22%), their overall structures are very similar, representingmore » a novel all {alpha}-helical fold, and indicate similar function. However, their lack of any known DNA-binding structural motifs and their unfavorable electrostatic properties imply that MtlR/YggD are unlikely to bind a specific DNA operator directly as proposed earlier. This structural observation is further corroborated by in vitro DNA-binding studies of E. coli MtlR (Ec-MtlR), which detected no interaction of Ec-MtlR with the well characterized mannitol operator/promoter region. Therefore, MtlR/YggD belongs to a new class of transcription factors in bacteria that may regulate gene expression indirectly as a part of a larger transcriptional complex.« less

A functional role of Rv1738 in Mycobacterium tuberculosis persistence suggested by racemic protein crystallography

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

Bunker, Richard D.; Mandal, Kalyaneswar; Bashiri, Ghader

Racemic protein crystallography was used to determine the X-ray structure of the predicted Mycobacterium tuberculosis protein Rv1738, which had been completely recalcitrant to crystallization in its natural L-form. Native chemical ligation was used to synthesize both L-protein and D-protein enantiomers of Rv1738. Crystallization of the racemic {D-protein + L-protein} mixture was immediately successful. The resulting crystals diffracted to high resolution and also enabled facile structure determination because of the quantized phases of the data from centrosymmetric crystals. The X-ray structure of Rv1738 revealed striking similarity with bacterial hibernation factors, despite minimal sequence similarity. As a result, we predict that Rv1738,more » which is highly up-regulated in conditions that mimic the onset of persistence, helps trigger dormancy by association with the bacterial ribosome.« less

A functional role of Rv1738 in Mycobacterium tuberculosis persistence suggested by racemic protein crystallography

DOE PAGES

Bunker, Richard D.; Mandal, Kalyaneswar; Bashiri, Ghader; ...

2015-04-07

Racemic protein crystallography was used to determine the X-ray structure of the predicted Mycobacterium tuberculosis protein Rv1738, which had been completely recalcitrant to crystallization in its natural L-form. Native chemical ligation was used to synthesize both L-protein and D-protein enantiomers of Rv1738. Crystallization of the racemic {D-protein + L-protein} mixture was immediately successful. The resulting crystals diffracted to high resolution and also enabled facile structure determination because of the quantized phases of the data from centrosymmetric crystals. The X-ray structure of Rv1738 revealed striking similarity with bacterial hibernation factors, despite minimal sequence similarity. As a result, we predict that Rv1738,more » which is highly up-regulated in conditions that mimic the onset of persistence, helps trigger dormancy by association with the bacterial ribosome.« less

Characterization of the amino acid contribution to the folding degree of proteins.

PubMed

Estrada, Ernesto

2004-03-01

The folding degree index (Estrada, Bioinformatics 2002;18:697-704) is extended to account for the contribution of amino acids to folding. First, the mathematical formalism for extending the folding degree index is presented. Then, the amino acid contributions to folding degree of several proteins are used to analyze its relation to secondary structure. The possibilities of using these contributions in helping or checking the assignation of secondary structure to amino acids are also introduced. The influence of external factors to the amino acids contribution to folding degree is studied through the temperature effect on ribonuclease A. Finally, the analysis of 3D protein similarity through the use of amino acid contributions to folding degree is studied by selecting a series of lysozymes. These results are compared to that obtained by sequence alignment (2D similarity) and 3D superposition of the structures, showing the uniqueness of the current approach. Copyright 2004 Wiley-Liss, Inc.

The Crystal Structure of PF-8, the DNA Polymerase Accessory Subunit from Kaposi's Sarcoma-Associated Herpesvirus

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

Baltz, Jennifer L.; Filman, David J.; Ciustea, Mihai

2009-12-01

Kaposi's sarcoma-associated herpesvirus is an emerging pathogen whose mechanism of replication is poorly understood. PF-8, the presumed processivity factor of Kaposi's sarcoma-associated herpesvirus DNA polymerase, acts in combination with the catalytic subunit, Pol-8, to synthesize viral DNA. We have solved the crystal structure of residues 1 to 304 of PF-8 at a resolution of 2.8 {angstrom}. This structure reveals that each monomer of PF-8 shares a fold common to processivity factors. Like human cytomegalovirus UL44, PF-8 forms a head-to-head dimer in the form of a C clamp, with its concave face containing a number of basic residues that are predictedmore » to be important for DNA binding. However, there are several differences with related proteins, especially in loops that extend from each monomer into the center of the C clamp and in the loops that connect the two subdomains of each protein, which may be important for determining PF-8's mode of binding to DNA and to Pol-8. Using the crystal structures of PF-8, the herpes simplex virus catalytic subunit, and RB69 bacteriophage DNA polymerase in complex with DNA and initial experiments testing the effects of inhibition of PF-8-stimulated DNA synthesis by peptides derived from Pol-8, we suggest a model for how PF-8 might form a ternary complex with Pol-8 and DNA. The structure and the model suggest interesting similarities and differences in how PF-8 functions relative to structurally similar proteins.« less

Demonstration of Functional Similarity of Proposed Biosimilar ABP 501 to Adalimumab.

PubMed

Velayudhan, Jyoti; Chen, Yuh-Feng; Rohrbach, Amanda; Pastula, Christina; Maher, Gwen; Thomas, Heather; Brown, Ryan; Born, Teresa L

2016-08-01

Due to the complex molecular structure and proprietary manufacturing processes of monoclonal antibodies (mAbs), differences in structure and function may be expected during development of biosimilar mAbs. Important regulatory requirements for approval of biosimilar products involve comprehensive assessments of any potential differences between proposed biosimilars and reference mAbs, including differences in all known mechanisms of action, using sensitive and relevant methods. Any identified structural differences should not result in differences in biofunctional or clinical activity. A comprehensive assessment comparing the Amgen biosimilar candidate ABP 501 with FDA-licensed adalimumab (adalimumab [US]) and EU-authorized adalimumab (adalimumab [EU]) was conducted to demonstrate similarity in biofunctional activity. The functional similarity assessment included testing of binding kinetics to soluble tumor necrosis factor α (TNFα) and relative binding to transmembrane TNFα. The neutralization of TNFα-induced caspase activation, TNFα- and lymphotoxin-α (LTα)-induced chemokine production, and cytotoxicity was also tested. Binding to Fc-gamma receptors FcγRIa, FcγRIIa (131H), FcγRIIIa (158V and 158F), and neonatal Fc receptor (FcRn) was compared with the reference mAbs, as was antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity. The data demonstrate that ABP 501 is similar to both adalimumab (US) and adalimumab (EU) with respect to evaluated biofunctional activities. Similarity in biofunctional activity is a critical component of the totality of evidence required for demonstration of biosimilarity. The functional similarity demonstrated for ABP 501 comprehensively assesses the known mechanisms of action of adalimumab, supporting the conclusion that ABP 501, adalimumab (US), and adalimumab (EU) are likely to be clinically similar.

Super elongation complex contains a TFIIF-related subcomplex

PubMed Central

Knutson, Bruce A.; Smith, Marissa L.; Walker-Kopp, Nancy; Xu, Xia

2016-01-01

ABSTRACT Super elongation complex (SEC) belongs to a family of RNA polymerase II (Pol II) elongation factors that has similar properties as TFIIF, a general transcription factor that increases the transcription elongation rate by reducing pausing. Although SEC has TFIIF-like functional properties, it apparently lacks sequence and structural homology. Using HHpred, we find that SEC contains an evolutionarily related TFIIF-like subcomplex. We show that the SEC subunit ELL interacts with the Pol II Rbp2 subunit, as expected for a TFIIF-like factor. These findings suggest a new model for how SEC functions as a Pol II elongation factor and how it suppresses Pol II pausing. PMID:27223670

Heritable Individual-Specific and Allele-Specific Chromatin Signatures in Humans

PubMed Central

McDaniell, Ryan; Lee, Bum-Kyu; Song, Lingyun; Liu, Zheng; Boyle, Alan P.; Erdos, Michael R.; Scott, Laura J.; Morken, Mario A.; Kucera, Katerina S.; Battenhouse, Anna; Keefe, Damian; Collins, Francis S.; Willard, Huntington F.; Lieb, Jason D.; Furey, Terrence S.; Crawford, Gregory E.; Iyer, Vishwanath R.; Birney, Ewan

2010-01-01

The extent to which variation in chromatin structure and transcription factor binding may influence gene expression, and thus underlie or contribute to variation in phenotype, is unknown. To address this question, we cataloged both individual-to-individual variation and differences between homologous chromosomes within the same individual (allele-specific variation) in chromatin structure and transcription factor binding in lymphoblastoid cells derived from individuals of geographically diverse ancestry. Ten percent of active chromatin sites were individual-specific; a similar proportion were allele-specific. Both individual-specific and allele-specific sites were commonly transmitted from parent to child, which suggests that they are heritable features of the human genome. Our study shows that heritable chromatin status and transcription factor binding differ as a result of genetic variation and may underlie phenotypic variation in humans. PMID:20299549

Emotional intelligence is a second-stratum factor of intelligence: evidence from hierarchical and bifactor models.

PubMed

MacCann, Carolyn; Joseph, Dana L; Newman, Daniel A; Roberts, Richard D

2014-04-01

This article examines the status of emotional intelligence (EI) within the structure of human cognitive abilities. To evaluate whether EI is a 2nd-stratum factor of intelligence, data were fit to a series of structural models involving 3 indicators each for fluid intelligence, crystallized intelligence, quantitative reasoning, visual processing, and broad retrieval ability, as well as 2 indicators each for emotion perception, emotion understanding, and emotion management. Unidimensional, multidimensional, hierarchical, and bifactor solutions were estimated in a sample of 688 college and community college students. Results suggest adequate fit for 2 models: (a) an oblique 8-factor model (with 5 traditional cognitive ability factors and 3 EI factors) and (b) a hierarchical solution (with cognitive g at the highest level and EI representing a 2nd-stratum factor that loads onto g at λ = .80). The acceptable relative fit of the hierarchical model confirms the notion that EI is a group factor of cognitive ability, marking the expression of intelligence in the emotion domain. The discussion proposes a possible expansion of Cattell-Horn-Carroll theory to include EI as a 2nd-stratum factor of similar standing to factors such as fluid intelligence and visual processing.

Zeroing In on Mindfulness Facets: Similarities, Validity, and Dimensionality across Three Independent Measures.

PubMed

Siegling, Alex B; Petrides, K V

2016-01-01

The field of mindfulness has seen a proliferation of psychometric measures, characterised by differences in operationalisation and conceptualisation. To illuminate the scope of, and offer insights into, the diversity apparent in the burgeoning literature, two distinct samples were used to examine the similarities, validity, and dimensionality of mindfulness facets and subscales across three independent measures: the Five Facet Mindfulness Questionnaire (FFMQ), Philadelphia Mindfulness Scale (PHLMS), and Toronto Mindfulness Scale (TMS). Results revealed problematic associations of FFMQ Observe with the other FFMQ facets and supported a four-factor structure (omitting this facet), while disputing the originally envisaged five-factor model; thus, solidifying a pattern in the literature. Results also confirmed the bidimensional nature of the PHLMS and TMS subscales, respectively. A joint Confirmatory Factor Analysis showed that PHLMS Acceptance could be assimilated within the FFMQ's four-factor model (as a distinct factor). The study offers a way of understanding interrelationships between the available mindfulness scales, so as to help practitioners and researchers make a more informed choice when conceptualising and operationalising mindfulness.

Zeroing In on Mindfulness Facets: Similarities, Validity, and Dimensionality across Three Independent Measures

PubMed Central

Siegling, Alex B.; Petrides, K. V.

2016-01-01

The field of mindfulness has seen a proliferation of psychometric measures, characterised by differences in operationalisation and conceptualisation. To illuminate the scope of, and offer insights into, the diversity apparent in the burgeoning literature, two distinct samples were used to examine the similarities, validity, and dimensionality of mindfulness facets and subscales across three independent measures: the Five Facet Mindfulness Questionnaire (FFMQ), Philadelphia Mindfulness Scale (PHLMS), and Toronto Mindfulness Scale (TMS). Results revealed problematic associations of FFMQ Observe with the other FFMQ facets and supported a four-factor structure (omitting this facet), while disputing the originally envisaged five-factor model; thus, solidifying a pattern in the literature. Results also confirmed the bidimensional nature of the PHLMS and TMS subscales, respectively. A joint Confirmatory Factor Analysis showed that PHLMS Acceptance could be assimilated within the FFMQ’s four-factor model (as a distinct factor). The study offers a way of understanding interrelationships between the available mindfulness scales, so as to help practitioners and researchers make a more informed choice when conceptualising and operationalising mindfulness. PMID:27055017

Structure of the catalytic domain of Plasmodium falciparum ARF GTPase-activating protein (ARFGAP)

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

Cook, William J.; Senkovich, Olga; Chattopadhyay, Debasish

2012-03-26

The crystal structure of the catalytic domain of the ADP ribosylation factor GTPase-activating protein (ARFGAP) from Plasmodium falciparum has been determined and refined to 2.4 {angstrom} resolution. Multiwavelength anomalous diffraction (MAD) data were collected utilizing the Zn{sup 2+} ion bound at the zinc-finger domain and were used to solve the structure. The overall structure of the domain is similar to those of mammalian ARFGAPs. However, several amino-acid residues in the area where GAP interacts with ARF1 differ in P. falciparum ARFGAP. Moreover, a number of residues that form the dimer interface in the crystal structure are unique in P. falciparummore » ARFGAP.« less

Validation of the Center for Epidemiological Studies Depression Scale among Korean Adolescents.

PubMed

Heo, Eun-Hye; Choi, Kyeong-Sook; Yu, Je-Chun; Nam, Ji-Ae

2018-02-01

The Center for Epidemiological Studies Depression Scale (CES-D) is designed to measure the current level of depressive symptomatology in the general population. However, no review has examined whether the scale is reliable and valid among children and adolescents in Korea. The purpose of this study was to test whether the Korean form of the CES-D is valid in adolescents. Data were obtained from 1,884 adolescents attending grades 1-3 in Korean middle schools. Reliability was evaluated by internal consistency (Cronbach's alpha). Concurrent validity was evaluated by a correlation analysis between the CES-D and other scales. Construct validity was evaluated by exploratory factor and confirmatory factor analyses. The internal consistency coefficient for the entire group was 0.88. The CES-D was positively correlated with scales that measure negative psychological constructs, such as the State Anxiety Inventory for Children, the Korean Social Anxiety Scale for Children and Adolescents, and the Reynold Suicidal Ideation Questionnaire, but it was negatively correlated with scales that measure positive psychological constructs, such as the Korean version of the Rosenberg Self-Esteem Scale and the Connor-Davidson Resilience Scale-2. The CES-D was examined by three-dimensional exploratory factor analysis, and the three-factor structure of the scale explained 53.165% of the total variance. The variance explained by factor I was 24.836%, that explained by factor II was 15.988%, and that explained by factor III was 12.341%. The construct validity of the CES-D was tested by confirmatory factor analysis, and we applied the entire group's data using a three-factor hierarchical model. The fit index showed a level similar to those of other countries' adolescent samples. The CES-D has high internal consistency and addresses psychological constructs similar to those addressed by other scales. The CES-D showed a three-factor structure in an exploratory factor analysis. The present findings suggest that the CES-D is a useful and reliable tool for measuring depression in Korean adolescents.

Suspensions of polymer-grafted nanoparticles with added polymers-Structure and effective pair-interactions.

PubMed

Chandran, Sivasurender; Saw, Shibu; Kandar, A K; Dasgupta, C; Sprung, M; Basu, J K

2015-08-28

We present the results of combined experimental and theoretical (molecular dynamics simulations and integral equation theory) studies of the structure and effective interactions of suspensions of polymer grafted nanoparticles (PGNPs) in the presence of linear polymers. Due to the absence of systematic experimental and theoretical studies of PGNPs, it is widely believed that the structure and effective interactions in such binary mixtures would be very similar to those of an analogous soft colloidal material-star polymers. In our study, polystyrene-grafted gold nanoparticles with functionality f = 70 were mixed with linear polystyrene (PS) of two different molecular weights for obtaining two PGNP:PS size ratios, ξ = 0.14 and 2.76 (where, ξ = Mg/Mm, Mg and Mm being the molecular weights of grafting and matrix polymers, respectively). The experimental structure factor of PGNPs could be modeled with an effective potential (Model-X), which has been found to be widely applicable for star polymers. Similarly, the structure factor of the blends with ξ = 0.14 could be modeled reasonably well, while the structure of blends with ξ = 2.76 could not be captured, especially for high density of added polymers. A model (Model-Y) for effective interactions between PGNPs in a melt of matrix polymers also failed to provide good agreement with the experimental data for samples with ξ = 2.76 and high density of added polymers. We tentatively attribute this anomaly in modeling the structure factor of blends with ξ = 2.76 to the questionable assumption of Model-X in describing the added polymers as star polymers with functionality 2, which gets manifested in both polymer-polymer and polymer-PGNP interactions especially at higher fractions of added polymers. The failure of Model-Y may be due to the neglect of possible many-body interactions among PGNPs mediated by matrix polymers when the fraction of added polymers is high. These observations point to the need for a new framework to understand not only the structural behavior of PGNPs but also possibly their dynamics and thermo-mechanical properties as well.

Understanding the Anatomic Basis for Obstructive Sleep Apnea Syndrome in Adolescents

PubMed Central

Kim, Christopher; Bagchi, Sheila; Keenan, Brendan T.; Comyn, François-Louis; Wang, Stephen; Tapia, Ignacio E.; Huang, Shirley; Traylor, Joel; Torigian, Drew A.; Bradford, Ruth M.; Marcus, Carole L.

2015-01-01

Rationale: Structural risk factors for obstructive sleep apnea syndrome (OSAS) in adolescents have not been well characterized. Because many adolescents with OSAS are obese, we hypothesized that the anatomic OSAS risk factors would be more similar to those in adults than those in children. Objectives: To investigate the anatomic risk factors in adolescents with OSAS compared with obese and lean control subjects using magnetic resonance imaging (MRI). Methods: Three groups of adolescents (age range: 12–16 yr) underwent MRI: obese individuals with OSAS (n = 49), obese control subjects (n = 38), and lean control subjects (n = 50). Measurements and Main Results: We studied 137 subjects and found that (1) obese adolescents with OSAS had increased adenotonsillar tissue compared with obese and lean control subjects; (2) obese OSAS adolescents had a smaller nasopharyngeal airway than control subjects; (3) the size of other upper airway soft tissue structures (volume of the tongue, parapharyngeal fat pads, lateral walls, and soft palate) was similar between subjects with OSAS and obese control subjects; (4) although there were no major craniofacial abnormalities in most of the adolescents with OSAS, the ratio of soft tissue to craniofacial space surrounding the airway was increased; and (5) there were sex differences in the pattern of lymphoid proliferation. Conclusions: Increased size of the pharyngeal lymphoid tissue, rather than enlargement of the upper airway soft tissue structures, is the primary anatomic risk factor for OSAS in obese adolescents. These results are important for clinical decision making and suggest that adenotonsillectomy should be considered as the initial treatment for OSAS in obese adolescents, a group that has poor continuous positive airway pressure adherence and difficulty in achieving weight loss. PMID:25835282

Arthroprotective Effects of Cf-02 Sharing Structural Similarity with Quercetin.

PubMed

Liu, Feng-Cheng; Lu, Jeng-Wei; Chien, Chiao-Yun; Huang, Hsu-Shan; Lee, Chia-Chung; Lien, Shiu-Bii; Lin, Leou-Chyr; Chen, Liv Weichien; Ho, Yi-Jung; Shen, Min-Chung; Ho, Ling-Jun; Lai, Jenn-Haung

2018-05-14

In this study, we synthesized hundreds of analogues based on the structure of small-molecule inhibitors (SMIs) that were previously identified in our laboratory with the aim of identifying potent yet safe compounds for arthritis therapeutics. One of the analogues was shown to share structural similarity with quercetin, a potent anti-inflammatory flavonoid present in many different fruits and vegetables. We investigated the immunomodulatory effects of this compound, namely 6-(2,4-difluorophenyl)-3-(3-(trifluoromethyl)phenyl)-2 H -benzo[ e ][1,3]oxazine-2,4(3 H )-dione (Cf-02), in a side-by-side comparison with quercetin. Chondrocytes were isolated from pig joints or the joints of patients with osteoarthritis that had undergone total knee replacement surgery. Several measures were used to assess the immunomodulatory potency of these compounds in tumor necrosis factor (TNF-α)-stimulated chondrocytes. Characterization included the protein and mRNA levels of molecules associated with arthritis pathogenesis as well as the inducible nitric oxide synthase (iNOS)⁻nitric oxide (NO) system and matrix metalloproteinases (MMPs) in cultured chondrocytes and proteoglycan, and aggrecan degradation in cartilage explants. We also examined the activation of several important transcription factors, including nuclear factor-kappaB (NF-κB), interferon regulatory factor-1 (IRF-1), signal transducer and activator of transcription-3 (STAT-3), and activator protein-1 (AP-1). Our overall results indicate that the immunomodulatory potency of Cf-02 is fifty-fold more efficient than that of quercetin without any indication of cytotoxicity. When tested in vivo using the induced edema method, Cf-02 was shown to suppress inflammation and cartilage damage. The proposed method shows considerable promise for the identification of candidate disease-modifying immunomodulatory drugs and leads compounds for arthritis therapeutics.

High-pressure crystal structure of elastically isotropic CaTiO3 perovskite under hydrostatic and non-hydrostatic conditions.

PubMed

Zhao, Jing; Ross, Nancy L; Wang, Di; Angel, Ross J

2011-11-16

The structural evolution of orthorhombic CaTiO3 perovskite has been studied using high-pressure single-crystal x-ray diffraction under hydrostatic conditions up to 8.1 GPa and under a non-hydrostatic stress field formed in a diamond anvil cell (DAC) up to 4.7 GPa. Under hydrostatic conditions, the TiO6 octahedra become more tilted and distorted with increasing pressure, similar to other 2:4 perovskites. Under non-hydrostatic conditions, the experiments do not show any apparent difference in the internal structural variation from hydrostatic conditions and no additional tilts and distortions in the TiO6 octahedra are observed, even though the lattice itself becomes distorted due to the non-hydrostatic stress. The similarity between the hydrostatic and non-hydrostatic cases can be ascribed to the fact that CaTiO3 perovskite is nearly elastically isotropic and, as a consequence, its deviatoric unit-cell volume strain produced by the non-hydrostatic stress is very small; in other words, the additional octahedral tilts relevant to the extra unit-cell volume associated with the deviatoric unit-cell volume strain may be totally neglected. This study further addresses the role that three factors--the elastic properties, the crystal orientation and the pressure medium--have on the structural evolution of an orthorhombic perovskite loaded in a DAC under non-hydrostatic conditions. The influence of these factors can be clearly visualized by plotting the three-dimensional distribution of the deviatoric unit-cell volume strain in relation to the cylindrical axis of the DAC and indicates that, if the elasticity of a perovskite is nearly isotropic as it is for CaTiO3, the other two factors become relatively insignificant.

Design and prediction of new anticoagulants as a selective Factor IXa inhibitor via three-dimensional quantitative structure-property relationships of amidinobenzothiophene derivatives.

PubMed

Gao, Jia-Suo; Tong, Xu-Peng; Chang, Yi-Qun; He, Yu-Xuan; Mei, Yu-Dan; Tan, Pei-Hong; Guo, Jia-Liang; Liao, Guo-Chao; Xiao, Gao-Keng; Chen, Wei-Min; Zhou, Shu-Feng; Sun, Ping-Hua

2015-01-01

Factor IXa (FIXa), a blood coagulation factor, is specifically inhibited at the initiation stage of the coagulation cascade, promising an excellent approach for developing selective and safe anticoagulants. Eighty-four amidinobenzothiophene antithrombotic derivatives targeting FIXa were selected to establish three-dimensional quantitative structure-activity relationship (3D-QSAR) and three-dimensional quantitative structure-selectivity relationship (3D-QSSR) models using comparative molecular field analysis and comparative similarity indices analysis methods. Internal and external cross-validation techniques were investigated as well as region focusing and bootstrapping. The satisfactory q (2) values of 0.753 and 0.770, and r (2) values of 0.940 and 0.965 for 3D-QSAR and 3D-QSSR, respectively, indicated that the models are available to predict both the inhibitory activity and selectivity on FIXa against Factor Xa, the activated status of Factor X. This work revealed that the steric, hydrophobic, and H-bond factors should appropriately be taken into account in future rational design, especially the modifications at the 2'-position of the benzene and the 6-position of the benzothiophene in the R group, providing helpful clues to design more active and selective FIXa inhibitors for the treatment of thrombosis. On the basis of the three-dimensional quantitative structure-property relationships, 16 new potent molecules have been designed and are predicted to be more active and selective than Compound 33, which has the best activity as reported in the literature.

Forest structure within barred owl (Strix varia) home ranges in the eastern cascade range, Washington

Treesearch

Peter H. Singleton

2015-01-01

Competitive interactions with Barred Owls (Strix varia) are an important factor contributing to the decline of the Northern Spotted Owl (Strix occidentalis caurina) population. Understanding the degree of similarity in fine-scale habitat associations for Spotted Owls and Barred Owls will help land managers evaluate whether...

Familial Correlates of Overt and Relational Aggression between Young Adolescent Siblings

ERIC Educational Resources Information Center

Yu, Jeong Jin; Gamble, Wendy C.

2008-01-01

Multi-group confirmatory factor analysis and multi-group structural equation modeling were used to test correlates of overt and relational aggression between young adolescent siblings across four groups (i.e., male/male, male/female, female/male, and female/female sibling pairs), using 433 predominately European American families. Similar patterns…

A Comparative Exploration of Learning Pathways and Transition Systems in Denmark and Australia

ERIC Educational Resources Information Center

Murray, Philomena; Polesel, John

2013-01-01

In the area of education and training, different configurations of government with different institutional structures may produce similar or quite different educational and employment outcomes. Other factors come into play in assessing outcomes. For example, young people's transitions from education to work are shaped by a variety of structural…

Searching for Tools versus Asking for Answers: A Taxonomy of Counselee Behavioral Styles during Career Counseling.

ERIC Educational Resources Information Center

Sagiv, Lilach

1999-01-01

A taxonomy of decision behavior styles (independence/dependence, active/passive, insightful/not) tested with 372 career counseling clients was supported by similar structure analysis and confirmatory factor analysis. Counselors were more likely to be satisfied with decisions of clients they perceived to be insightful. (SK)

Systematic deletion of homeobox genes in Podospora anserina uncovers their roles in shaping the fruiting body.

PubMed

Coppin, Evelyne; Berteaux-Lecellier, Véronique; Bidard, Frédérique; Brun, Sylvain; Ruprich-Robert, Gwenaël; Espagne, Eric; Aït-Benkhali, Jinane; Goarin, Anne; Nesseir, Audrey; Planamente, Sara; Debuchy, Robert; Silar, Philippe

2012-01-01

Higher fungi, which comprise ascomycetes and basidiomycetes, play major roles in the biosphere. Their evolutionary success may be due to the extended dikaryotic stage of their life cycle, which is the basis for their scientific name: the Dikarya. Dikaryosis is maintained by similar structures, the clamp in basidiomycetes and the crozier in ascomycetes. Homeodomain transcription factors are required for clamp formation in all basidiomycetes studied. We identified all the homeobox genes in the filamentous ascomycete fungus Podospora anserina and constructed deletion mutants for each of these genes and for a number of gene combinations. Croziers developed normally in these mutants, including those with up to six deleted homeogenes. However, some mutants had defects in maturation of the fruiting body, an effect that could be rescued by providing wild-type maternal hyphae. Analysis of mutants deficient in multiple homeogenes revealed interactions between the genes, suggesting that they operate as a complex network. Similar to their role in animals and plants, homeodomain transcription factors in ascomycetes are involved in shaping multicellular structures.

Systematic Deletion of Homeobox Genes in Podospora anserina Uncovers Their Roles in Shaping the Fruiting Body

PubMed Central

Coppin, Evelyne; Berteaux-Lecellier, Véronique; Bidard, Frédérique; Brun, Sylvain; Ruprich-Robert, Gwenaël; Espagne, Eric; Aït-Benkhali, Jinane; Goarin, Anne; Nesseir, Audrey; Planamente, Sara; Debuchy, Robert; Silar, Philippe

2012-01-01

Higher fungi, which comprise ascomycetes and basidiomycetes, play major roles in the biosphere. Their evolutionary success may be due to the extended dikaryotic stage of their life cycle, which is the basis for their scientific name: the Dikarya. Dikaryosis is maintained by similar structures, the clamp in basidiomycetes and the crozier in ascomycetes. Homeodomain transcription factors are required for clamp formation in all basidiomycetes studied. We identified all the homeobox genes in the filamentous ascomycete fungus Podospora anserina and constructed deletion mutants for each of these genes and for a number of gene combinations. Croziers developed normally in these mutants, including those with up to six deleted homeogenes. However, some mutants had defects in maturation of the fruiting body, an effect that could be rescued by providing wild-type maternal hyphae. Analysis of mutants deficient in multiple homeogenes revealed interactions between the genes, suggesting that they operate as a complex network. Similar to their role in animals and plants, homeodomain transcription factors in ascomycetes are involved in shaping multicellular structures. PMID:22662159

Why were California's wine country fires so destructive?

USGS Publications Warehouse

Keeley, Jon E.

2017-01-01

As of late October more than a dozen wildfires north of San Francisco had killed more than 40 people, burned approximately 160,000 acres and destroyed more than 7,000 structures.This tragic loss of life and property is unprecedented in California. However, the fires are not anomalous events in terms of their size, intensity or the speed with which they spread. Indeed, the path of the destructive Tubbs fire in Napa and Sonoma counties mirrors that of the Hanley fire of 1964. This extreme wind-driven fire burned under similar conditions, across much of the same landscape and covered an area substantially greater than the recent Tubbs fire.Strikingly, though, no lives were lost during the Hanley fire and only 29 structures were destroyed. Why did these two fires, 50 years apart, burn on the same general landscape, under similar extreme winds, with such different human impacts? Fire scientists will study these events intensively to parse out the relative importance of various factors. But it is clear that two factors probably were major contributors: wind and population growth.

Factor Analysis of the Brazilian Version of UPPS Impulsive Behavior Scale.

PubMed

Sediyama, Cristina Y N; Moura, Ricardo; Garcia, Marina S; da Silva, Antonio G; Soraggi, Carolina; Neves, Fernando S; Albuquerque, Maicon R; Whiteside, Setephen P; Malloy-Diniz, Leandro F

2017-01-01

Objective: To examine the internal consistency and factor structure of the Brazilian adaptation of the UPPS Impulsive Behavior Scale. Methods: UPPS is a self-report scale composed by 40 items assessing four factors of impulsivity: (a) urgency, (b) lack of premeditation; (c) lack of perseverance; (d) sensation seeking. In the present study 384 participants (278 women and 106 men), who were recruited from schools, universities, leisure centers and workplaces fulfilled the UPPS scale. An exploratory factor analysis was performed by using Varimax factor rotation and Kaiser Normalization, and we also conducted two confirmatory analyses to test the independency of the UPPS components found in previous analysis. Results: Results showed a decrease in mean UPPS total scores with age and this analysis showed that the youngest participants (below 30 years) scored significantly higher than the other groups over 30 years. No difference in gender was found. Cronbach's alpha, results indicated satisfactory values for all subscales, with similar high values for the subscales and confirmatory factor analysis indexes also indicated a poor model fit. The results of two exploratory factor analysis were satisfactory. Conclusion: Our results showed that the Portuguese version has the same four-factor structure of the original and previous translations of the UPPS.

High-confidence prediction of global interactomes based on genome-wide coevolutionary networks

PubMed Central

Juan, David; Pazos, Florencio; Valencia, Alfonso

2008-01-01

Interacting or functionally related protein families tend to have similar phylogenetic trees. Based on this observation, techniques have been developed to predict interaction partners. The observed degree of similarity between the phylogenetic trees of two proteins is the result of many different factors besides the actual interaction or functional relationship between them. Such factors influence the performance of interaction predictions. One aspect that can influence this similarity is related to the fact that a given protein interacts with many others, and hence it must adapt to all of them. Accordingly, the interaction or coadaptation signal within its tree is a composite of the influence of all of the interactors. Here, we introduce a new estimator of coevolution to overcome this and other problems. Instead of relying on the individual value of tree similarity between two proteins, we use the whole network of similarities between all of the pairs of proteins within a genome to reassess the similarity of that pair, thereby taking into account its coevolutionary context. We show that this approach offers a substantial improvement in interaction prediction performance, providing a degree of accuracy/coverage comparable with, or in some cases better than, that of experimental techniques. Moreover, important information on the structure, function, and evolution of macromolecular complexes can be inferred with this methodology. PMID:18199838

High-confidence prediction of global interactomes based on genome-wide coevolutionary networks.

PubMed

Juan, David; Pazos, Florencio; Valencia, Alfonso

2008-01-22

Interacting or functionally related protein families tend to have similar phylogenetic trees. Based on this observation, techniques have been developed to predict interaction partners. The observed degree of similarity between the phylogenetic trees of two proteins is the result of many different factors besides the actual interaction or functional relationship between them. Such factors influence the performance of interaction predictions. One aspect that can influence this similarity is related to the fact that a given protein interacts with many others, and hence it must adapt to all of them. Accordingly, the interaction or coadaptation signal within its tree is a composite of the influence of all of the interactors. Here, we introduce a new estimator of coevolution to overcome this and other problems. Instead of relying on the individual value of tree similarity between two proteins, we use the whole network of similarities between all of the pairs of proteins within a genome to reassess the similarity of that pair, thereby taking into account its coevolutionary context. We show that this approach offers a substantial improvement in interaction prediction performance, providing a degree of accuracy/coverage comparable with, or in some cases better than, that of experimental techniques. Moreover, important information on the structure, function, and evolution of macromolecular complexes can be inferred with this methodology.

Molecular Cloning, Bioinformatics Analysis and Expression of Insulin-Like Growth Factor 2 from Tianzhu White Yak, Bos grunniens

PubMed Central

Zhang, Quanwei; Gong, Jishang; Wang, Xueying; Wu, Xiaohu; Li, Yalan; Ma, Youji; Zhang, Yong; Zhao, Xingxu

2014-01-01

The IGF family is essential for normal embryonic and postnatal development and plays important roles in the immune system, myogenesis, bone metabolism and other physiological functions, which makes the study of its structure and biological characteristics important. Tianzhu white yak (Bos grunniens) domesticated under alpine hypoxia environments, is well adapted to survive and grow against severe hypoxia and cold temperatures for extended periods. In this study, a full coding sequence of the IGF2 gene of Tianzhu white yak was amplified by reverse transcription PCR and rapid-amplification of cDNA ends (RACE) for the first time. The cDNA sequence revealed an open reading frame of 450 nucleotides, encoding a protein with 179 amino acids. Its expression in different tissues was also studied by Real time PCR. Phylogenetic tree analysis indicated that yak IGF2 was similar to Bos taurus, and 3D structure showed high similarity with the human IGF2. The putative full CDS of yak IGF2 was amplified by PCR in five tissues, and cDNA sequence analysis showed high homology to bovine IGF2. Moreover the super secondary structure prediction showed a similar 3D structure with human IGF2. Its conservation in sequence and structure has facilitated research on IGF2 and its physiological function in yak. PMID:24394317

Distinct bacterial communities across a gradient of vegetation from a preserved Brazilian Cerrado.

PubMed

de Araujo, Ademir Sergio Ferreira; Bezerra, Walderly Melgaço; Dos Santos, Vilma Maria; Rocha, Sandra Mara Barbosa; Carvalho, Nilza da Silva; de Lyra, Maria do Carmo Catanho Pereira; Figueiredo, Marcia do Vale Barreto; de Almeida Lopes, Ângela Celis; Melo, Vania Maria Maciel

2017-04-01

The Cerrado biome in the Sete Cidades National Park, an Ecological Reserve in Northeastern Brazil, has conserved its native biodiversity and presents a variety of plants found in other savannas in Brazil. Despite this finding the soil microbial diversity and community structure are poorly understood. Therefore, we described soil bacterial diversity and distribution along a savanna vegetation gradient taking into account the prevailing environmental factors. The bacterial composition was retrieved by sequencing a fragment of the 16S ribosomal RNA gene. The bacterial operational taxonomic units (OTUs) were assigned to 37 different phyla, 96 classes, and 83 genera. At the phylum level, a core comprised by Proteobacteria, Acidobacteria, Actinobacteria, Firmicutes, Verrucomicrobia and Planctomycetes, was detected in all areas of Cerrado. 'Cerrado stricto sensu' and 'Cerradao' share more similarities between edaphic properties and vegetation and also present more similar bacterial communities, while 'Floresta decidual' and 'Campo graminoide' show the largest environmental differences and also more distinct bacterial communities. Proteobacteria (26%), Acidobacteria (21%) and Actinobacteria (21%) were the most abundant phyla within the four areas. All the samples present similar bacteria richness (alpha diversity) and the observed differences among them (beta diversity) were more related to the abundance of specific taxon OTUs compared to their presence or absence. Total organic C, N and P are the main abiotic factors structuring the bacterial communities. In summary, our findings show the bacterial community structure was clearly different across the Cerrado gradient, but that these environments share a bacterial phylum-core comprising Proteobacteria, Acidobacteria, Actinobacteria, Verrucomicrobia and Planctomycetes with other Brazilian savannas.

Simultaneous inactivation of sigma factors B and D interferes with light acclimation of the cyanobacterium Synechocystis sp. strain PCC 6803.

PubMed

Pollari, Maija; Ruotsalainen, Virpi; Rantamäki, Susanne; Tyystjärvi, Esa; Tyystjärvi, Taina

2009-06-01

In cyanobacteria, gene expression is regulated mainly at the level of transcription initiation, which is mediated by the RNA polymerase holoenzyme. The RNA polymerase core is catalytically active, while the sigma factor recognizes promoter sequences. Group 2 sigma factors are similar to the principal sigma factor but are nonessential. Group 2 sigma factors SigB and SigD are structurally the most similar sigma factors in Synechocystis sp. strain PCC 6803. Under standard growth conditions, simultaneous inactivation of sigB and sigD genes did not affect the growth, but the photosynthesis and growth of the DeltasigBD strain were slower than in the control strain at double light intensity. Light-saturated electron transfer rates and the fluorescence and thermoluminescence measurements showed that photosynthetic light reactions are fully functional in the DeltasigBD strain, but absorption and 77 K emission spectra measurements suggest that the light-harvesting system of the DeltasigBD strain does not acclimate normally to higher light intensity. Furthermore, the DeltasigBD strain is more sensitive to photoinhibition under bright light because impaired upregulation of psbA genes leads to insufficient PSII repair.

Microscopic neural image registration based on the structure of mitochondria

NASA Astrophysics Data System (ADS)

Cao, Huiwen; Han, Hua; Rao, Qiang; Xiao, Chi; Chen, Xi

2017-02-01

Microscopic image registration is a key component of the neural structure reconstruction with serial sections of neural tissue. The goal of microscopic neural image registration is to recover the 3D continuity and geometrical properties of specimen. During image registration, various distortions need to be corrected, including image rotation, translation, tissue deformation et.al, which come from the procedure of sample cutting, staining and imaging. Furthermore, there is only certain similarity between adjacent sections, and the degree of similarity depends on local structure of the tissue and the thickness of the sections. These factors make the microscopic neural image registration a challenging problem. To tackle the difficulty of corresponding landmarks extraction, we introduce a novel image registration method for Scanning Electron Microscopy (SEM) images of serial neural tissue sections based on the structure of mitochondria. The ellipsoidal shape of mitochondria ensures that the same mitochondria has similar shape between adjacent sections, and its characteristic of broad distribution in the neural tissue guarantees that landmarks based on the mitochondria distributed widely in the image. The proposed image registration method contains three parts: landmarks extraction between adjacent sections, corresponding landmarks matching and image deformation based on the correspondences. We demonstrate the performance of our method with SEM images of drosophila brain.

Four factors underlying mouse behavior in an open field

PubMed Central

Tanaka, Shoji; Young, Jared W.; Halberstadt, Adam L.; Masten, Virginia L.; Geyer, Mark A.

2012-01-01

The observation of the locomotor and exploratory behaviors of rodents in an open field is one of the most fundamental methods used in the field of behavioral pharmacology. A variety of behaviors can be recorded automatically and can readily generate a multivariate pattern of pharmacological effects. Nevertheless, the optimal ways to characterize observed behaviors and concomitant drug effects are still under development. The aim of this study was to extract meaningful behavioral factors that could explain variations in the observed variables from mouse exploration. Behavioral data were recorded from male C57BL/6J mice (n = 268) using the Behavioral Pattern Monitor (BPM). The BPM data were subjected to the exploratory factor analysis. The factor analysis extracted four factors: activity, sequential organization, diversive exploration, and inspective exploration. The activity factor and the two types of exploration factors correlated positively with one another, while the sequential organization factor negatively correlated with the remaining factors. The extracted factor structure constitutes a behavioral model of mouse exploration. This model will provide a platform on which one can assess the effects of psychoactive drugs and genetic manipulations on mouse exploratory behavior. Further studies are currently underway to examine the factor structure of similar multivariate data sets from humans tested in a human BPM. PMID:22569582

Four factors underlying mouse behavior in an open field.

PubMed

Tanaka, Shoji; Young, Jared W; Halberstadt, Adam L; Masten, Virginia L; Geyer, Mark A

2012-07-15

The observation of the locomotor and exploratory behaviors of rodents in an open field is one of the most fundamental methods used in the field of behavioral pharmacology. A variety of behaviors can be recorded automatically and can readily generate a multivariate pattern of pharmacological effects. Nevertheless, the optimal ways to characterize observed behaviors and concomitant drug effects are still under development. The aim of this study was to extract meaningful behavioral factors that could explain variations in the observed variables from mouse exploration. Behavioral data were recorded from male C57BL/6J mice (n=268) using the Behavioral Pattern Monitor (BPM). The BPM data were subjected to the exploratory factor analysis. The factor analysis extracted four factors: activity, sequential organization, diversive exploration, and inspective exploration. The activity factor and the two types of exploration factors correlated positively with one another, while the sequential organization factor negatively correlated with the remaining factors. The extracted factor structure constitutes a behavioral model of mouse exploration. This model will provide a platform on which one can assess the effects of psychoactive drugs and genetic manipulations on mouse exploratory behavior. Further studies are currently underway to examine the factor structure of similar multivariate data sets from humans tested in a human BPM. Copyright © 2012 Elsevier B.V. All rights reserved.

The association of daily hassles and uplifts with family and life satisfaction: does cultural orientation make a difference?

PubMed

Lavee, Yoav; Ben-Ari, Adital

2008-03-01

The study examined similarities and differences between people having individualist and collectivist cultural orientations in terms of what they perceive as stressful and uplifting experiences in their daily lives, and the relation between daily experiences and family and life satisfaction. Data were collected from two representative community samples (697 Jews and 303 Arabs). Each sample was grouped into individualist and collectivist cultural orientations. The two cultural orientation groups differed with respect to the appraisal of positive and negative daily experiences. A structural equation modeling (SEM) multi-group analysis indicated a similar factor structure for hassles and uplifts in both groups. However, the two groups differed in the effects of positive and negative daily occurrences on family and life satisfaction.

Cross-ethnic generalizability of the three-factor model of psychopathy: the Youth Psychopathic Traits Inventory in an incarcerated sample of native Dutch and Moroccan immigrant boys.

PubMed

Veen, Violaine C; Stevens, Gonneke W J M; Andershed, Henrik; Raaijmakers, Quinten A W; Doreleijers, Theo A H; Vollebergh, Wilma A M

2011-01-01

Previous research provides support for the existence of the psychopathy construct in youths. However, studies regarding the psychometric properties of psychopathy measures with ethnic minority youths are lacking. In the present study, the three-factor structure of the Youth Psychopathic Traits Inventory (YPI) was examined for both native Dutch youth (N=158) and an ethnic minority group, Moroccans (N=141), in an incarcerated adolescent population in the Netherlands. Our results showed that the three-factor structure of the YPI is comparable across an ethnic majority and an ethnic minority group in an incarcerated sample in the Netherlands. Moreover, associations between psychopathic traits and mental health problems were similar for both ethnic groups. The results support the cross-ethnic generalizability of the three-factor model of psychopathy as measured through the Youth Psychopathic Traits Inventory. Copyright © 2011 Elsevier Ltd. All rights reserved.

Validation of the Polish version of the Multidimensional Body-Self Relations Questionnaire among women.

PubMed

Brytek-Matera, Anna; Rogoza, Radosław

2015-03-01

In Poland, appropriate means to assess body image are relatively limited. The aim of the study was to evaluate the psychometric properties of the Polish version of the Multidimensional Body-Self Relations Questionnaire (MBSRQ). To do so, a sample of 341 females ranging in age from 18 to 35 years (M = 23.09; SD = 3.14) participated in the present study. Owing to the fact that the confirmatory factor analysis of the original nine-factor model was not well fitted to the data (RMSEA = 0.06; CFI = 0.75) the exploratory approach was employed. Based on parallel analysis and minimum average partial an eight-factor structure of the Polish version of the MBSRQ was distinguished. Exploratory factor analysis revealed a factorial structure similar to the original version. The proposed model was tested using an exploratory structural equation modelling approach which resulted in good fit (RMSEA = 0.04; CFI = 0.91). In the present study, the internal reliability assessed by McDonald's ω coefficient amounts from 0.66 to 0.91. In conclusion, the Polish version of the MBSRQ is a useful measure for the attitudinal component of body image assessment.

Differentiating responses to contaminants from responses to other environmental factors for benthic biota in freshwater ecosystems

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

Day, K.E.; Reynoldson, T.B.; Rosenberg, D.M.

1995-12-31

Many ecological risk assessments (ERAS) of lakes, rivers and streams compare measurements of benthic community structure in specific areas of contamination to similar measurements in reference or ``clean`` areas as a basis for determining impact. However, despite numerous studies documenting alterations of benthic communities as a result of stress, the success of correctly assessing the ``health`` or degradation of these communities depends on how well responses to contamination can be discriminated from responses to other environmental factors. It is important in the ERA process to adequately describe benthic communities and to determine how natural environmental factors (e.g., substrate particle sizemore » and texture, organic content, water quality, pH, seston, etc.) may be driving benthic community structure. This knowledge is particularly important when reference areas are distant from stressed areas. This presentation will provide an overview of the environmental factors that are important in structuring natural benthic communities in rivers and lakes and discuss approaches that may be useful in differentiating between natural variability and anthropogenic stress in ERA. Several case studies from the Laurentian Great Lakes and the Fraser River watershed in British Columbia will be discussed.« less

Synoptic Factors Affecting Structure Predictability of Hurricane Alex (2016)

NASA Astrophysics Data System (ADS)

Gonzalez-Aleman, J. J.; Evans, J. L.; Kowaleski, A. M.

2016-12-01

On January 7, 2016, a disturbance formed over the western North Atlantic basin. After undergoing tropical transition, the system became the first hurricane of 2016 - and the first North Atlantic hurricane to form in January since 1938. Already an extremely rare hurricane event, Alex then underwent extratropical transition [ET] just north of the Azores Islands. We examine the factors affecting Alex's structural evolution through a new technique called path-clustering. In this way, 51 ensembles from the European Centre for Medium-Range Weather Forecasts Ensemble Prediction System (ECMWF-EPS) are grouped based on similarities in the storm's path through the Cyclone Phase Space (CPS). The differing clusters group various possible scenarios of structural development represented in the ensemble forecasts. As a result, it is possible to shed light on the role of the synoptic scale in changing the structure of this hurricane in the midlatitudes through intercomparison of the most "realistic" forecast of the evolution of Alex and the other physically plausible modes of its development.

The structure of harassment and abuse in the workplace: a factorial comparison of two measures.

PubMed

Fendrich, Michael; Woodword, Paul; Richman, Judith A

2002-08-01

The structures of two measures examining negative experiences in the workplace, one focusing primarily on sexual harassment (SEQ) and one focusing on workplace abuse (GWA), were examined in detail. This article investigated whether the five subscales for the relatively unexplored measure (GWA) are reliably measured by a single underlying construct. It also investigated whether the two workplace-based measures are distinct but related constructs and the consistency of their factor structure across genders. Using a large and diverse organizational survey derived from a Midwestern university, analyses supported the distinctiveness of the two measures and showed that the factor structures for the two constructs were remarkably similar across genders. Analyses also suggested that indices of extreme behavior within each of the constructs were not reliably measured. The findings have important implications for data collection strategies in research focused on negative workplace experiences. This study provides considerable support for the continued use of both measures in research investigating the impact of adverse workplace environment on health.

Using register data to deduce patterns of social exchange.

PubMed

Jansson, Fredrik

2017-07-01

This paper presents a novel method for deducting propensities for social exchange between individuals based on the choices they make, and based on factors such as country of origin, sex, school grades and socioeconomic background. The objective here is to disentangle the effect of social ties from the other factors, in order to find patterns of social exchange. This is done through a control-treatment design on analysing available data, where the 'treatment' is similarity of choices between socially connected individuals, and the control is similarity of choices between non-connected individuals. Structural dependencies are controlled for and effects from different classes are pooled through a mix of methods from network and meta-analysis. The method is demonstrated and tested on Swedish register data on students at upper secondary school. The results show that having similar grades is a predictor of social exchange. Also, previous results from Norwegian data are replicated, showing that students cluster based on country of origin.

Generalized Structured Component Analysis with Uniqueness Terms for Accommodating Measurement Error

PubMed Central

Hwang, Heungsun; Takane, Yoshio; Jung, Kwanghee

2017-01-01

Generalized structured component analysis (GSCA) is a component-based approach to structural equation modeling (SEM), where latent variables are approximated by weighted composites of indicators. It has no formal mechanism to incorporate errors in indicators, which in turn renders components prone to the errors as well. We propose to extend GSCA to account for errors in indicators explicitly. This extension, called GSCAM, considers both common and unique parts of indicators, as postulated in common factor analysis, and estimates a weighted composite of indicators with their unique parts removed. Adding such unique parts or uniqueness terms serves to account for measurement errors in indicators in a manner similar to common factor analysis. Simulation studies are conducted to compare parameter recovery of GSCAM and existing methods. These methods are also applied to fit a substantively well-established model to real data. PMID:29270146

Formation of gut-like structures in vitro from mouse embryonic stem cells.

PubMed

Torihashi, Shigeko

2006-01-01

Embryonic stem (ES) cells have the potential to differentiate into all cell types originating from the three germ layers; however, there are still few reports about the formation of functional organs from embryonic stem cells. Recently, we reported that by hanging drops of mouse ES cells, embryoid bodies (EBs) formed gut-like structures in vitro composed of three layers corresponding to the epithelium, lamina propria, and musculature. The morphological features and the process of formation are similar to gut and its organogenesis in vivo. Thus, this is a good model for development of the gut and a useful tool for analysis of the factors required for gut organogenesis. The protocol basically involves a method of hanging drops to make EBs, which are then plated on coated dishes for outgrowth. EBs develop to form gut-like structures when induced to spontaneously enter a program of differentiation in vitro without addition of any extrinsic factors.

Genetic Transfer of Salmonella typhimurium and Escherichia coli Lipopolysaccharide Antigens to Escherichia coli K-12

PubMed Central

Jones, Randall T.; Koeltzow, Donald E.; Stocker, B. A. D.

1972-01-01

Escherichia coli K-12 ϰ971 was crossed with a smooth Salmonella typhimurium donor, HfrK6, which transfers early the ilv-linked rfa region determining lipopolysaccharide (LPS) core structure. Two ilv+ hybrids differing in their response to the LPS-specific phages FO and C21 were then crossed with S. typhimurium HfrK9, which transfers early the rfb gene cluster determining O repeat unit structure. Most recombinants selected for his+ (near rfb) were agglutinated by Salmonella factor 4 antiserum. Transfer of an F′ factor (FS400) carrying the rfb–his region of S. typhimurium to the same two ilv+ hybrids gave similar results. LPS extracted from two ilv+,his+, factor 4-positive hybrids contained abequose, the immunodominant sugar for factor 4 specificity. By contrast, his+ hybrids obtained from ϰ971 itself by similar HfrK9 and F′FS400 crosses were not agglutinated by factor 4 antiserum, indicating that the parental E. coli ϰ971 does not have the capacity to attach Salmonella O repeat units to its LPS core. It is concluded that the Salmonella rfb genes are expressed only in E. coli ϰ971 hybrids which have also acquired ilv-linked genes (presumably rfa genes affecting core structure or O-translocase ability, or both) from a S. typhimurium donor. When E. coli ϰ971 was crossed with a smooth E. coli donor, Hfr59, of serotype O8, which transfers his early, most his+ recombinants were agglutinated by E. coli O8 antiserum and lysed by the O8-specific phage, Ω8. This suggests that, although the parental E. coli K-12 strain ϰ971 cannot attach Salmonella-specific repeat units to its LPS core, it does have the capacity to attach E. coli O8-specific repeat units. PMID:4559827

Factor analytic study of two questionnaires measuring oral health-related quality of life among children and adults in New Zealand, Germany and Poland.

PubMed

Tapsoba, H; Deschamps, J P; Leclercq, M H

2000-01-01

A questionnaire designed to measure oral health-related quality of life (OHRQOL) in adults and children was assessed for its factorial structure and reliability using data from the Second International Collaborative Study on Oral Health Outcomes in New Zealand, Poland and Germany. Principal component analysis with orthogonal and oblique rotation was applied. The three-factor structure hypothesized for the children's questionnaire (self-reported oral disease symptoms, perceived oral well-being, social and physical functioning) was confirmed in New Zealand and Poland, and two self-reported oral disease symptom dimensions emerged in Germany. Five factors instead of the three hypothesized were identified for adults: two dimensions of symptoms were identified, and social and physical functioning appeared to be independent dimensions of OHRQOL. Similarity between the factors was demonstrated in all three countries. The reliability of the questionnaire ranged from moderate to excellent depending on the dimension and the country. These findings provide preliminary evidence of the cross-cultural stability of the OHRQOL questionnaire in New Zealand, Poland and Germany, for both children and adults. Further investigations by the present authors of the properties of the instrument in other samples will focus on demonstrating the stability and replicability of the factor structure identified here.

Assessment of the structural validity of the domestic violence healthcare providers’ survey questionnaire using a Nigerian sample

PubMed Central

John, Ime A; Lawoko, Stephen

2010-01-01

Abstract: Background: There has been increased advocacy to involve healthcare providers in the prevention of intimate partner violence (IPV) through screening for it in healthcare. Yet, only one in ten providers screen for IPV, suggesting barriers. Understanding the readiness of healthcare providers to screen for IPV is therefore paramount. The Domestic Violence Healthcare Provider Survey Scales (DVHPSS) is a previously validated, comprehensive scale to study readiness of healthcare providers to screen for IPV. However, an understanding of its usefulness in the Sub-Saharan African context remains elusive. The current study undertook to examine the structural validity of the DVHPSS in Nigeria. Methods: Exploratory factor analysis and Cronbach's Alpha were run to reveal the factorial structure and reliability of the instrument/subscales respectively. Established thresholds were used to determine significant factor loadings and alphas coefficient. Results: A six factor model emerged, with 2 factors similar to the original scale, another two differing slightly and a further two factors resulting from a splitting up of the original combination of victim/provider safety to having distinct victim and provider safety subscales. Conclusions: With slight modifications, the DVHPSS can be use to study IPV screening among Nigerian healthcare professionals. Introducing screening protocols could promote better understanding of crucial questions that were lost in the analysis. PMID:21483202

Comparison of the structural basis for thermal stability between archaeal and bacterial proteins.

PubMed

Ding, Yanrui; Cai, Yujie; Han, Yonggang; Zhao, Bingqiang

2012-01-01

In this study, the structural basis for thermal stability in archaeal and bacterial proteins was investigated. There were many common factors that confer resistance to high temperature in both archaeal and bacterial proteins. These factors include increases in the Lys content, the bends and blanks of secondary structure, the Glu content of salt bridge; decreases in the number of main-side chain hydrogen bond and exposed surface area, and changes in the bends and blanks of amino acids. Certainly, the utilization of charged amino acids to form salt bridges is a primary factor. In both heat-resistant archaeal and bacterial proteins, most Glu and Asp participate in the formation of salt bridges. Other factors may influence either archaeal or bacterial protein thermostability, which includes the more frequent occurrence of shorter 3(10)-helices and increased hydrophobicity in heat-resistant archaeal proteins. However, there were increases in average helix length, the Glu content in salt bridges, temperature factors and decreases in the number of main-side chain hydrogen bonds, uncharged-uncharged hydrogen bonds, hydrophobicity, and buried and exposed polar surface area in heat-resistant bacterial proteins. Evidently, there are few similarities and many disparities between the heat-resistant mechanisms of archaeal and bacterial proteins.

Extending Structural Analyses of the Rosenberg Self-Esteem Scale to Consider Criterion-Related Validity: Can Composite Self-Esteem Scores Be Good Enough?

PubMed

Donnellan, M Brent; Ackerman, Robert A; Brecheen, Courtney

2016-01-01

Although the Rosenberg Self-Esteem Scale (RSES) is the most widely used measure of global self-esteem in the literature, there are ongoing disagreements about its factor structure. This methodological debate informs how the measure should be used in substantive research. Using a sample of 1,127 college students, we test the overall fit of previously specified models for the RSES, including a newly proposed bifactor solution (McKay, Boduszek, & Harvey, 2014 ). We extend previous work by evaluating how various latent factors from these structural models are related to a set of criterion variables frequently studied in the self-esteem literature. A strict unidimensional model poorly fit the data, whereas models that accounted for correlations between negatively and positively keyed items tended to fit better. However, global factors from viable structural models had similar levels of association with criterion variables and with the pattern of results obtained with a composite global self-esteem variable calculated from observed scores. Thus, we did not find compelling evidence that different structural models had substantive implications, thereby reducing (but not eliminating) concerns about the integrity of the self-esteem literature based on overall composite scores for the RSES.

Discovering perturbation of modular structure in HIV progression by integrating multiple data sources through non-negative matrix factorization.

PubMed

Ray, Sumanta; Maulik, Ujjwal

2016-12-20

Detecting perturbation in modular structure during HIV-1 disease progression is an important step to understand stage specific infection pattern of HIV-1 virus in human cell. In this article, we proposed a novel methodology on integration of multiple biological information to identify such disruption in human gene module during different stages of HIV-1 infection. We integrate three different biological information: gene expression information, protein-protein interaction information and gene ontology information in single gene meta-module, through non negative matrix factorization (NMF). As the identified metamodules inherit those information so, detecting perturbation of these, reflects the changes in expression pattern, in PPI structure and in functional similarity of genes during the infection progression. To integrate modules of different data sources into strong meta-modules, NMF based clustering is utilized here. Perturbation in meta-modular structure is identified by investigating the topological and intramodular properties and putting rank to those meta-modules using a rank aggregation algorithm. We have also analyzed the preservation structure of significant GO terms in which the human proteins of the meta-modules participate. Moreover, we have performed an analysis to show the change of coregulation pattern of identified transcription factors (TFs) over the HIV progression stages.

Principles of ipsilateral and contralateral cortico-cortical connectivity in the mouse.

PubMed

Goulas, Alexandros; Uylings, Harry B M; Hilgetag, Claus C

2017-04-01

Structural connectivity among cortical areas provides the substrate for information exchange in the cerebral cortex and is characterized by systematic patterns of presence or absence of connections. What principles govern this cortical wiring diagram? Here, we investigate the relation of physical distance and cytoarchitecture with the connectional architecture of the mouse cortex. Moreover, we examine the relation between patterns of ipsilateral and contralateral connections. Our analysis reveals a mirrored and attenuated organization of contralateral connections when compared with ipsilateral connections. Both physical distance and cytoarchitectonic similarity of cortical areas are related to the presence or absence of connections. Notably, our analysis demonstrates that the combination of these factors relates better to cortico-cortical connectivity than each factor in isolation and that the two factors relate differently to ipsilateral and contralateral connectivity. Physical distance is more tightly related to the presence or absence of ipsilateral connections, but its relevance greatly diminishes for contralateral connections, while the contribution of cytoarchitectonic similarity remains relatively stable. Our results, together with similar findings in the cat and macaque cortex, suggest that a common set of principles underlies the macroscale wiring of the mammalian cerebral cortex.

A Surrogate for Debye-Waller Factors from Dynamic Stokes Shifts

PubMed Central

Zhong, Qin; Johnson, Jerainne; Aamer, Khaled A.; Tyagi, Madhusudan

2011-01-01

We show that the short-time behavior of time-resolved fluorescence Stokes shifts (TRSS) are similar to that of the intermediate scattering function obtained from neutron scattering at q near the peak in the static structure factor for glycerol. This allows us to extract a Debye-Waller (DW) factor analog from TRSS data at times as short as 1 ps in a relatively simple way. Using the time-domain relaxation data obtained by this method we show that DW factors evaluated at times ≥ 40 ps can be directly influenced by α relaxation and thus should be used with caution when evaluating relationships between fast and slow dynamics in glassforming systems. PMID:21701673

Psychometric properties and factor structure of the Fertility Problem Inventory in a sample of infertile women undergoing fertility treatment.

PubMed

Gourounti, K; Anagnostopoulos, F; Vaslamatzis, G

2011-10-01

to examine the psychometric properties of the Fertility Problem Inventory (FPI) originally developed by Newton et al. (1999); as there are no data concerning the factorial structure of the FPI, a special focus is placed on construct validity through factor analysis. public hospital in Athens, Greece. a cross-sectional study. 108 women undergoing fertility treatment with in-vitro fertilisation. the FPI was 'forward-backward' translated from English to Greek. The translated instrument was then administered to a set of infertile women for pilot testing. Principal axis factoring with promax rotation was used to test the factor structure of the FPI. Measures of anxiety State Trait Anxiety Inventory, depression (Center for Epidemiologic Studies--Depression Scale) and mood states Profile of Mood States were used to assess the convergent validity of the FPI. Cronbach's α was used to measure internal consistency of the FPI scales. exploratory factor analysis suggested four factors. The majority of relationship and sexual concern items grouped into one solid factor, named 'spousal concern'. The original scales of social concern, need for parenthood and rejection of childfree lifestyle were reproduced after rearranging nine cross-loading items. Construct validity was confirmed by computing correlations between the derived FPI scales and conceptually similar constructions of anxiety, depression and mood states. Internal consistency reliability was satisfactory. the FPI was found to have a relatively stable factor structure and satisfactory reliability, and convergent and discriminant validity. The FPI may enable researchers and clinicians to apply a reliable measure that focuses on various/many dimensions of infertility-related stress. Copyright © 2010 Elsevier Ltd. All rights reserved.

Family quality of life of Chinese families of children with intellectual disabilities.

PubMed

Hu, X; Wang, M; Fei, X

2012-01-01

The concepts of quality of life and family quality of life (FQOL) are increasingly being studied in the field of intellectual disabilities (ID) in China as important frameworks for: (1) assessing families' need for supports and services; (2) guiding organisational and service delivery system changes; and (3) evaluating quality family outcomes. The present study focused on exploring the perceptions of Chinese families who have a child with an ID regarding FQOL as well as examining the factor structure of FQOL concept from Chinese families. The Chinese version of the Family Quality of Life Scale was used to survey Chinese families living in the urban and suburban areas of Beijing who have a child with ID. A total of 442 families participated in this study. Confirmatory factor analysis was used to test the factor structure of FQOL. Multivariate analysis was also used to examine group differences among families in terms of family demographic variables. A five-factor structure of the FQOL construct was found in the Chinese sample, suggesting a similar factor structure found from US families in the literature. Different living conditions (e.g. housing and transportation) tended to affect significantly families' satisfaction ratings of their FQOL. It is also found that family income and severity of disability of the child are predictors of families' satisfaction ratings of FQOL. The preliminary findings of this study suggest a cross-cultural factor structure comparability of FQOL between samples in the USA and China. Results call for further examination of the family-centred service and support as a mediator on the interactive relationship between family characteristics, family needs and FQOL outcomes. © 2011 The Authors. Journal of Intellectual Disability Research © 2011 Blackwell Publishing Ltd.

Structure and Dynamics of Hydroxyl-Functionalized Protic Ammonium Carboxylate Ionic Liquids.

PubMed

Thummuru, Dhileep Nagi Reddy; Mallik, Bhabani S

2017-10-26

We performed classical molecular dynamics simulations to investigate the structure and dynamics of protic ionic liquids, 2-hydroxy ethylammonium acetate, ethylammonium hydroxyacetate, and 2-hydroxyethylammonium hydroxyacetate at ambient conditions. Structural properties such as density, radial distribution functions, spatial distribution functions, and structure factors have been calculated. Dynamic properties such as mean square displacements, as well as residence and hydrogen bond dynamics have also been calculated. Hydrogen bond lifetimes and residence times change with the addition of hydroxyl groups. We observe that when a hydroxyl group is present on the cation, dynamics become very slow and it forms a strong hydrogen bond with carboxylate oxygen atoms of the anion. The hydroxyl functionalized ILs show more dynamic diversity than structurally similar ILs.

Rationally engineered flavin-dependent oxidase reveals steric control of dioxygen reduction.

PubMed

Zafred, Domen; Steiner, Barbara; Teufelberger, Andrea R; Hromic, Altijana; Karplus, P Andrew; Schofield, Christopher J; Wallner, Silvia; Macheroux, Peter

2015-08-01

The ability of flavoenzymes to reduce dioxygen varies greatly, and is controlled by the protein environment, which may cause either a rapid reaction (oxidases) or a sluggish reaction (dehydrogenases). Previously, a 'gatekeeper' amino acid residue was identified that controls the reactivity to dioxygen in proteins from the vanillyl alcohol oxidase superfamily of flavoenzymes. We have identified an alternative gatekeeper residue that similarly controls dioxygen reactivity in the grass pollen allergen Phl p 4, a member of this superfamily that has glucose dehydrogenase activity and the highest redox potential measured in a flavoenzyme. A substitution at the alternative gatekeeper site (I153V) transformed the enzyme into an efficient oxidase by increasing dioxygen reactivity by a factor of 60,000. An inverse exchange (V169I) in the structurally related berberine bridge enzyme (BBE) decreased its dioxygen reactivity by a factor of 500. Structural and biochemical characterization of these and additional variants showed that our model enzymes possess a cavity that binds an anion and resembles the 'oxyanion hole' in the proximity of the flavin ring. We showed also that steric control of access to this site is the most important parameter affecting dioxygen reactivity in BBE-like enzymes. Analysis of flavin-dependent oxidases from other superfamilies revealed similar structural features, suggesting that dioxygen reactivity may be governed by a common mechanistic principle. Structural data are available in PDB database under the accession numbers 4PVE, 4PVH, 4PVJ, 4PVK, 4PWB, 4PWC and 4PZF. © 2015 FEBS.

Structural Similitude and Scaling Laws

NASA Technical Reports Server (NTRS)

Simitses, George J.

1998-01-01

Aircraft and spacecraft comprise the class of aerospace structures that require efficiency and wisdom in design, sophistication and accuracy in analysis and numerous and careful experimental evaluations of components and prototype, in order to achieve the necessary system reliability, performance and safety. Preliminary and/or concept design entails the assemblage of system mission requirements, system expected performance and identification of components and their connections as well as of manufacturing and system assembly techniques. This is accomplished through experience based on previous similar designs, and through the possible use of models to simulate the entire system characteristics. Detail design is heavily dependent on information and concepts derived from the previous steps. This information identifies critical design areas which need sophisticated analyses, and design and redesign procedures to achieve the expected component performance. This step may require several independent analysis models, which, in many instances, require component testing. The last step in the design process, before going to production, is the verification of the design. This step necessitates the production of large components and prototypes in order to test component and system analytical predictions and verify strength and performance requirements under the worst loading conditions that the system is expected to encounter in service. Clearly then, full-scale testing is in many cases necessary and always very expensive. In the aircraft industry, in addition to full-scale tests, certification and safety necessitate large component static and dynamic testing. Such tests are extremely difficult, time consuming and definitely absolutely necessary. Clearly, one should not expect that prototype testing will be totally eliminated in the aircraft industry. It is hoped, though, that we can reduce full-scale testing to a minimum. Full-scale large component testing is necessary in other industries as well, Ship building, automobile and railway car construction all rely heavily on testing. Regardless of the application, a scaled-down (by a large factor) model (scale model) which closely represents the structural behavior of the full-scale system (prototype) can prove to be an extremely beneficial tool. This possible development must be based on the existence of certain structural parameters that control the behavior of a structural system when acted upon by static and/or dynamic loads. If such structural parameters exist, a scaled-down replica can be built, which will duplicate the response of the full-scale system. The two systems are then said to be structurally similar. The term, then, that best describes this similarity is structural similitude. Similarity of systems requires that the relevant system parameters be identical and these systems be governed by a unique set of characteristic equations. Thus, if a relation or equation of variables is written for a system, it is valid for all systems which are similar to it. Each variable in a model is proportional to the corresponding variable of the prototype. This ratio, which plays an essential role in predicting the relationship between the model and its prototype, is called the scale factor.

Understanding Angiography-Based Aneurysm Flow Fields through Comparison with Computational Fluid Dynamics.

PubMed

Cebral, J R; Mut, F; Chung, B J; Spelle, L; Moret, J; van Nijnatten, F; Ruijters, D

2017-06-01

Hemodynamics is thought to be an important factor for aneurysm progression and rupture. Our aim was to evaluate whether flow fields reconstructed from dynamic angiography data can be used to realistically represent the main flow structures in intracranial aneurysms. DSA-based flow reconstructions, obtained during interventional treatment, were compared qualitatively with flow fields obtained from patient-specific computational fluid dynamics models and quantitatively with projections of the computational fluid dynamics fields (by computing a directional similarity of the vector fields) in 15 cerebral aneurysms. The average similarity between the DSA and the projected computational fluid dynamics flow fields was 78% in the parent artery, while it was only 30% in the aneurysm region. Qualitatively, both the DSA and projected computational fluid dynamics flow fields captured the location of the inflow jet, the main vortex structure, the intrasaccular flow split, and the main rotation direction in approximately 60% of the cases. Several factors affect the reconstruction of 2D flow fields from dynamic angiography sequences. The most important factors are the 3-dimensionality of the intrasaccular flow patterns and inflow jets, the alignment of the main vortex structure with the line of sight, the overlapping of surrounding vessels, and possibly frame rate undersampling. Flow visualization with DSA from >1 projection is required for understanding of the 3D intrasaccular flow patterns. Although these DSA-based flow quantification techniques do not capture swirling or secondary flows in the parent artery, they still provide a good representation of the mean axial flow and the corresponding flow rate. © 2017 by American Journal of Neuroradiology.

Factorial Validity and Gender Invariance of the Physical Activity Enjoyment Scale (PACES) in Older Adolescents

ERIC Educational Resources Information Center

Dunton, Genevieve Fridlund; Tscherne, James; Rodriguez, Daniel

2009-01-01

Documented gender differences in physical activity rates during adolescence (Grunbaum et al., 2004) pose the question of whether physical activity enjoyment similarly differs between boys and girls. However, a necessary precursor to research on this topic is that the factor structure of the PACES be equivalent across gender. Although gender…

Market structure in U.S. southern pine roundwood

Treesearch

Matthew F. Bingham; Jeffrey P. Prestemon; Douglas J. MacNair; Robert C. Abt

2003-01-01

Time series of commodity prices from multiple locations can behave as if responding to forces of spatial arbitrage. cvcn while such prices may instead be responding similarly to common factors aside from spatial arbitrage. Hence, while the Law of One Price may hold as a statistical concept, its acceptance is not sufficient to conclude market integration. We tested...

The factor structure of the Social Interaction Anxiety Scale and the Social Phobia Scale.

PubMed

Heidenreich, Thomas; Schermelleh-Engel, Karin; Schramm, Elisabeth; Hofmann, Stefan G; Stangier, Ulrich

2011-05-01

The Social Interaction Anxiety Scale (SIAS) and the Social Phobia Scale (SPS) are two compendium measures that have become some of the most popular self-report scales of social anxiety. Despite their popularity, it remains unclear whether it is necessary to maintain two separate scales of social anxiety. The primary objective of the present study was to examine the factor analytic structure of both measures to determine the factorial validity of each scale. For this purpose, we administered both scales to 577 patients at the beginning of outpatient treatment. Analyzing both scales simultaneously, a CFA with two correlated factors showed a better fit to the data than a single factor model. An additional EFA with an oblique rotation on all 40 items using the WLSMV estimator further supported the two factor solution. These results suggest that the SIAS and SPS measure similar, but not identical facets of social anxiety. Thus, our findings provide support to retain the SIAS and SPS as two separate scales. Copyright © 2011 Elsevier Ltd. All rights reserved.

Factor Structure, Internal Consistency, and Screening Sensitivity of the GARS-2 in a Developmental Disabilities Sample

PubMed Central

Volker, Martin A.; Dua, Elissa H.; Lopata, Christopher; Thomeer, Marcus L.; Toomey, Jennifer A.; Smerbeck, Audrey M.; Rodgers, Jonathan D.; Popkin, Joshua R.; Nelson, Andrew T.; Lee, Gloria K.

2016-01-01

The Gilliam Autism Rating Scale-Second Edition (GARS-2) is a widely used screening instrument that assists in the identification and diagnosis of autism. The purpose of this study was to examine the factor structure, internal consistency, and screening sensitivity of the GARS-2 using ratings from special education teaching staff for a sample of 240 individuals with autism or other significant developmental disabilities. Exploratory factor analysis yielded a correlated three-factor solution similar to that found in 2005 by Lecavalier for the original GARS. Though the three factors appeared to be reasonably consistent with the intended constructs of the three GARS-2 subscales, the analysis indicated that more than a third of the GARS-2 items were assigned to the wrong subscale. Internal consistency estimates met or exceeded standards for screening and were generally higher than those in previous studies. Screening sensitivity was .65 and specificity was .81 for the Autism Index using a cut score of 85. Based on these findings, recommendations are made for instrument revision. PMID:26981279

Crystal structure of enterococcus faecalis sly A-like transcriptional factor.

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

Wu, R.; Zhang, R.; Zagnitko, O.

2003-05-30

The crystal structure of a SlyA transcriptional regulator at 1.6 {angstrom} resolution is presented, and structural relationships between members of the MarR/SlyA family are discussed. The SlyA family, which includes SlyA, Rap, Hor, and RovA proteins, is widely distributed in bacterial and archaeal genomes. Current evidence suggests that SlyA-like factors act as repressors, activators, and modulators of gene transcription. These proteins have been shown to up-regulate the expression of molecular chaperones, acid-resistance proteins, and cytolysin, and down-regulate several biosynthetic enzymes. The structure of SlyA from Enterococcus faecalis, determined as a part of an ongoing structural genomics initiative (www.mcsg.anl.gov), revealed themore » same winged helix DNA-binding motif that was recently found in the MarR repressor from Escherichia coli and the MexR repressor from Pseudomonas aeruginosa, a sequence homologue of MarR. Phylogenetic analysis of the MarR/SlyA family suggests that Sly is placed between the SlyA and MarR subfamilies and shows significant sequence similarity to members of both subfamilies.« less

Archaeal RNA polymerase and transcription regulation

PubMed Central

Jun, Sung-Hoon; Reichlen, Matthew J.; Tajiri, Momoko; Murakami, Katsuhiko S.

2010-01-01

To elucidate the mechanism of transcription by cellular RNA polymerases (RNAPs), high resolution X-ray crystal structures together with structure-guided biochemical, biophysical and genetics studies are essential. The recently-solved X-ray crystal structures of archaeal RNA polymerase (RNAP) allow a structural comparison of the transcription machinery among all three domains of life. The archaea were once thought of closely related to bacteria, but they are now considered to be more closely related to the eukaryote at the molecular level than bacteria. According to these structures, the archaeal transcription apparatus, which includes RNAP and general transcription factors, is similar to the eukaryotic transcription machinery. Yet, the transcription regulators, activators and repressors, encoded by archaeal genomes are closely related to bacterial factors. Therefore, archaeal transcription appears to possess an intriguing hybrid of eukaryotic-type transcription apparatus and bacterial-like regulatory mechanisms. Elucidating the transcription mechanism in archaea, which possesses a combination of bacterial and eukaryotic transcription mechanisms that are commonly regarded as separate and mutually exclusive, can provide data that will bring basic transcription mechanisms across all three domains of life. PMID:21250781

The structure factor of primes

NASA Astrophysics Data System (ADS)

Zhang, G.; Martelli, F.; Torquato, S.

2018-03-01

Although the prime numbers are deterministic, they can be viewed, by some measures, as pseudo-random numbers. In this article, we numerically study the pair statistics of the primes using statistical-mechanical methods, particularly the structure factor S(k) in an interval M ≤slant p ≤slant M + L with M large, and L/M smaller than unity. We show that the structure factor of the prime-number configurations in such intervals exhibits well-defined Bragg-like peaks along with a small ‘diffuse’ contribution. This indicates that primes are appreciably more correlated and ordered than previously thought. Our numerical results definitively suggest an explicit formula for the locations and heights of the peaks. This formula predicts infinitely many peaks in any non-zero interval, similar to the behavior of quasicrystals. However, primes differ from quasicrystals in that the ratio between the location of any two predicted peaks is rational. We also show numerically that the diffuse part decays slowly as M and L increases. This suggests that the diffuse part vanishes in an appropriate infinite-system-size limit.

The molecular structure and catalytic mechanism of a quorum-quenching N-acyl-L-homoserine lactone hydrolase

PubMed Central

Kim, Myung Hee; Choi, Won-Chan; Kang, Hye Ok; Lee, Jong Suk; Kang, Beom Sik; Kim, Kyung-Jin; Derewenda, Zygmunt S.; Oh, Tae-Kwang; Lee, Choong Hwan; Lee, Jung-Kee

2005-01-01

In many Gram-negative bacteria, including a number of pathogens such as Pseudomonas aeruginosa and Erwinia carotovora, virulence factor production and biofilm formation are linked to the quorum-sensing systems that use diffusible N-acyl-l-homoserine lactones (AHLs) as intercellular messenger molecules. A number of organisms also contain genes coding for lactonases that hydrolyze AHLs into inactive products, thereby blocking the quorum-sensing systems. Consequently, these enzymes attract intense interest for the development of antiinfection therapies. However, the catalytic mechanism of AHL-lactonase is poorly understood and subject to controversy. We here report a 2.0-Å resolution structure of the AHL-lactonase from Bacillus thuringiensis and a 1.7-Å crystal structure of its complex with l-homoserine lactone. Despite limited sequence similarity, the enzyme shows remarkable structural similarities to glyoxalase II and RNase Z proteins, members of the metallo-β-lactamase superfamily. We present experimental evidence that AHL-lactonase is a metalloenzyme containing two zinc ions involved in catalysis, and we propose a catalytic mechanism for bacterial metallo-AHL-lactonases. PMID:16314577

Electron microscopy and in vitro deneddylation reveal similar architectures and biochemistry of isolated human and Flag-mouse COP9 signalosome complexes

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

Rockel, Beate; Schmaler, Tilo; Huang, Xiaohua

2014-07-25

Highlights: • Deneddylation rates of human erythrocyte and mouse fibroblast CSN are very similar. • 3D models of native human and mouse CSN reveal common architectures. • The cryo-structure of native mammalian CSN shows a horseshoe subunit arrangement. - Abstract: The COP9 signalosome (CSN) is a regulator of the ubiquitin (Ub) proteasome system (UPS). In the UPS, proteins are Ub-labeled for degradation by Ub ligases conferring substrate specificity. The CSN controls a large family of Ub ligases called cullin-RING ligases (CRLs), which ubiquitinate cell cycle regulators, transcription factors and DNA damage response proteins. The CSN possesses structural similarities with themore » 26S proteasome Lid complex and the translation initiation complex 3 (eIF3) indicating similar ancestry and function. Initial structures were obtained 14 years ago by 2D electron microscopy (EM). Recently, first 3D molecular models of the CSN were created on the basis of negative-stain EM and single-particle analysis, mostly with recombinant complexes. Here, we compare deneddylating activity and structural features of CSN complexes purified in an elaborate procedure from human erythrocytes and efficiently pulled down from mouse Flag-CSN2 B8 fibroblasts. In an in vitro deneddylation assay both the human and the mouse CSN complexes deneddylated Nedd8-Cul1 with comparable rates. 3D structural models of the erythrocyte CSN as well as of the mouse Flag-CSN were generated by negative stain EM and by cryo-EM. Both complexes show a central U-shaped segment from which several arms emanate. This structure, called the horseshoe, is formed by the PCI domain subunits. CSN5 and CSN6 point away from the horseshoe. Compared to 3D models of negatively stained CSN complexes, densities assigned to CSN2 and CSN4 are better defined in the cryo-map. Because biochemical and structural results obtained with CSN complexes isolated from human erythrocytes and purified by Flag-CSN pulldown from mouse B8 fibroblasts are very similar, Flag-CSN pulldowns are a proper alternative to CSN preparation from erythrocytes.« less

Acanthamoeba castellanii contains a ribosomal RNA enhancer binding protein which stimulates TIF-IB binding and transcription under stringent conditions.

PubMed

Yang, Q; Radebaugh, C A; Kubaska, W; Geiss, G K; Paule, M R

1995-11-11

The intergenic spacer (IGS) of Acanthamoeba castellanii rRNA genes contains repeated elements which are weak enhancers for transcription by RNA polymerase I. A protein, EBF, was identified and partially purified which binds to the enhancers and to several other sequences within the IGS, but not to other DNA fragments, including the rRNA core promoter. No consensus binding sequence could be discerned in these fragments and bound factor is in rapid equilibrium with unbound. EBF has functional characteristics similar to vertebrate upstream binding factors (UBF). Not only does it bind to the enhancer and other IGS elements, but it also stimulates binding of TIF-IB, the fundamental transcription initiation factor, to the core promoter and stimulates transcription from the promoter. Attempts to identify polypeptides with epitopes similar to rat or Xenopus laevis UBF suggest that structurally the protein from A.castellanii is not closely related to vertebrate UBF.

Acanthamoeba castellanii contains a ribosomal RNA enhancer binding protein which stimulates TIF-IB binding and transcription under stringent conditions.

PubMed Central

Yang, Q; Radebaugh, C A; Kubaska, W; Geiss, G K; Paule, M R

1995-01-01

The intergenic spacer (IGS) of Acanthamoeba castellanii rRNA genes contains repeated elements which are weak enhancers for transcription by RNA polymerase I. A protein, EBF, was identified and partially purified which binds to the enhancers and to several other sequences within the IGS, but not to other DNA fragments, including the rRNA core promoter. No consensus binding sequence could be discerned in these fragments and bound factor is in rapid equilibrium with unbound. EBF has functional characteristics similar to vertebrate upstream binding factors (UBF). Not only does it bind to the enhancer and other IGS elements, but it also stimulates binding of TIF-IB, the fundamental transcription initiation factor, to the core promoter and stimulates transcription from the promoter. Attempts to identify polypeptides with epitopes similar to rat or Xenopus laevis UBF suggest that structurally the protein from A.castellanii is not closely related to vertebrate UBF. Images PMID:7501455

Exploratory factor analysis of borderline personality disorder criteria in hospitalized adolescents.

PubMed

Becker, Daniel F; McGlashan, Thomas H; Grilo, Carlos M

2006-01-01

The authors examined the factor structure of borderline personality disorder (BPD) in hospitalized adolescents and also sought to add to the theoretical and clinical understanding of any homogeneous components by determining whether they may be related to specific forms of Axis I pathology. Subjects were 123 adolescent inpatients, who were reliably assessed with structured diagnostic interviews for Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition Axes I and II disorders. Exploratory factor analysis identified BPD components, and logistic regression analyses tested whether these components were predictive of specific Axis I disorders. Factor analysis revealed a 4-factor solution that accounted for 67.0% of the variance. Factor 1 ("suicidal threats or gestures" and "emptiness or boredom") predicted depressive disorders and alcohol use disorders. Factor 2 ("affective instability," "uncontrolled anger," and "identity disturbance") predicted anxiety disorders and oppositional defiant disorder. Factor 3 ("unstable relationships" and "abandonment fears") predicted only anxiety disorders. Factor 4 ("impulsiveness" and "identity disturbance") predicted conduct disorder and substance use disorders. Exploratory factor analysis of BPD criteria in adolescent inpatients revealed 4 BPD factors that appear to differ from those reported for similar studies of adults. The factors represent components of self-negation, irritability, poorly modulated relationships, and impulsivity--each of which is associated with characteristic Axis I pathology. These findings shed light on the nature of BPD in adolescents and may also have implications for treatment.

Structure of Escherichia coli AdhP (ethanol-inducible dehydrogenase) with bound NAD.

PubMed

Thomas, Leonard M; Harper, Angelica R; Miner, Whitney A; Ajufo, Helen O; Branscum, Katie M; Kao, Lydia; Sims, Paul A

2013-07-01

The crystal structure of AdhP, a recombinantly expressed alcohol dehydrogenase from Escherichia coli K-12 (substrain MG1655), was determined to 2.01 Å resolution. The structure, which was solved using molecular replacement, also included the structural and catalytic zinc ions and the cofactor nicotinamide adenine dinucleotide (NAD). The crystals belonged to space group P21, with unit-cell parameters a = 68.18, b = 118.92, c = 97.87 Å, β = 106.41°. The final R factor and Rfree were 0.138 and 0.184, respectively. The structure of the active site of AdhP suggested a number of residues that may participate in a proton relay, and the overall structure of AdhP, including the coordination to structural and active-site zinc ions, is similar to those of other tetrameric alcohol dehydrogenase enzymes.

Major depressive disorder and factorial dimensions among individuals with recent-onset spinal cord injury.

PubMed

Williamson, Meredith L C; Elliott, Timothy R

2013-02-01

We examine the rates of major depressive disorder, single episode determined by the Inventory to Diagnose Depression (IDD) in a clinical sample of persons with recent-onset spinal cord injury (SCI; ≤52 weeks) participating in an inpatient SCI rehabilitation program. We also analyzed the factor structure of the IDD measure in an attempt to replicate the factor structure reported by Frank et al. (1992), and we examined item endorsement patterns. A retrospective chart review was conducted. Participants were 354 individuals (93 women, 261 men) in an inpatient SCI rehabilitation program. Fifteen percent of the sample met criteria for a major depressive disorder (MDD). A higher rate of depression was observed among women. A "dysphoria" factor accounted for 24% of the variance in the final four-factor model. The four-factor solution explained a total of 35.5% of the variance, with an "anhedonia" factor contributing 4.6%, a "sleep" factor contributing 3.5%, and an "appetite" factor contributing 3.5%, respectively. Items assessing symptoms of insomnia, weight loss, worrying about health, and decreased energy had the highest percentage of endorsement to meet Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) criteria for clinical significance. The rate of single episodes of MDD determined by the IDD parallels the rate observed with the Patient Health Questionnaire-9 (PHQ-9). The factor structure of the IDD was similar to that reported by Frank et al. (1992). Information provided by the IDD about the presence and severity of MDD symptoms can inform interventions for persons with SCI.

Dual energy CT with one full scan and a second sparse-view scan using structure preserving iterative reconstruction (SPIR)

NASA Astrophysics Data System (ADS)

Wang, Tonghe; Zhu, Lei

2016-09-01

Conventional dual-energy CT (DECT) reconstruction requires two full-size projection datasets with two different energy spectra. In this study, we propose an iterative algorithm to enable a new data acquisition scheme which requires one full scan and a second sparse-view scan for potential reduction in imaging dose and engineering cost of DECT. A bilateral filter is calculated as a similarity matrix from the first full-scan CT image to quantify the similarity between any two pixels, which is assumed unchanged on a second CT image since DECT scans are performed on the same object. The second CT image from reduced projections is reconstructed by an iterative algorithm which updates the image by minimizing the total variation of the difference between the image and its filtered image by the similarity matrix under data fidelity constraint. As the redundant structural information of the two CT images is contained in the similarity matrix for CT reconstruction, we refer to the algorithm as structure preserving iterative reconstruction (SPIR). The proposed method is evaluated on both digital and physical phantoms, and is compared with the filtered-backprojection (FBP) method, the conventional total-variation-regularization-based algorithm (TVR) and prior-image-constrained-compressed-sensing (PICCS). SPIR with a second 10-view scan reduces the image noise STD by a factor of one order of magnitude with same spatial resolution as full-view FBP image. SPIR substantially improves over TVR on the reconstruction accuracy of a 10-view scan by decreasing the reconstruction error from 6.18% to 1.33%, and outperforms TVR at 50 and 20-view scans on spatial resolution with a higher frequency at the modulation transfer function value of 10% by an average factor of 4. Compared with the 20-view scan PICCS result, the SPIR image has 7 times lower noise STD with similar spatial resolution. The electron density map obtained from the SPIR-based DECT images with a second 10-view scan has an average error of less than 1%.

Geometrical comparison of two protein structures using Wigner-D functions.

PubMed

Saberi Fathi, S M; White, Diana T; Tuszynski, Jack A

2014-10-01

In this article, we develop a quantitative comparison method for two arbitrary protein structures. This method uses a root-mean-square deviation characterization and employs a series expansion of the protein's shape function in terms of the Wigner-D functions to define a new criterion, which is called a "similarity value." We further demonstrate that the expansion coefficients for the shape function obtained with the help of the Wigner-D functions correspond to structure factors. Our method addresses the common problem of comparing two proteins with different numbers of atoms. We illustrate it with a worked example. © 2014 Wiley Periodicals, Inc.

Cross-tail magnetic flux ropes as observed by the GEOTAIL spacecraft

NASA Technical Reports Server (NTRS)

Lepping, R. P.; Fairfield, D. H.; Jones, J.; Frank, L. A.; Paterson, W. R.; Kokubun, S.; Yamamoto, T.

1995-01-01

Ten transient magnetic structures in Earth's magnetotail, as observed in GEOTAIL measurements, selected for early 1993 (at (-) X(sub GSM) = 90 - 130 Earth radii), are shown to have helical magnetic field configurations similar to those of interplanetary magnetic clouds at 1 AU but smaller in size by a factor of approximately = 700. Such structures are shown to be well approximated by a comprehensive magnetic force-free flux-rope model. For this limited set of 10 events the rope axes are seen to be typically aligned with the Y(sub GSM) axis and the average diameter of these structures is approximately = 15 Earth radii.

Confirmatory factor analysis of the Revised UCLA Loneliness Scale (UCLA LS-R) in individuals over 65.

PubMed

Ausín, Berta; Muñoz, Manuel; Martín, Teresa; Pérez-Santos, Eloísa; Castellanos, Miguel Ángel

2018-01-08

The UCLA LS-R is the most extensively used scale to assess loneliness. However, few studies examine the scale's use on older individuals. The goal of the study is to analyse the suitability of the scale´s structure for assessing older individuals. The UCLA LS-R scale was administered to a random sample of 409 community-dwelling residents of Madrid (53% women) aged 65-84 years (obtained from the MentDis_ICF65+ study). Confirmatory factor analysis was used to assess the factor structure of the UCLA LS-R. The internal consistency of the scale obtained a Cronbach's alpha of .85. All the analysed models of factor structure of the UCLA LS-R achieved a fairly good fit and RMSEA values over .80. The models that best fit the empirical data are those of Hojat (1982) and Borges et al. (2008). The data suggest an equivalent effectiveness of UCLA LS-R in adults under 65 and over 65, which may indicate a similar structure of the loneliness construct in both populations. This outcome is consistent with the idea that loneliness has two dimensions: emotional loneliness and social loneliness. The use of short measures that are easy to apply and interpret should help primary care professionals identify loneliness problems in older individuals sooner and more accurately.

[Convergent origin of repeats in genes coding for globular proteins. An analysis of the factors determining the presence of inverted and symmetrical repeats].

PubMed

Solov'ev, V V; Kel', A E; Kolchanov, N A

1989-01-01

The factors, determining the presence of inverted and symmetrical repeats in genes coding for globular proteins, have been analysed. An interesting property of genetical code has been revealed in the analysis of symmetrical repeats: the pairs of symmetrical codons corresponded to pairs of amino acids with mostly similar physical-chemical parameters. This property may explain the presence of symmetrical repeats and palindromes only in genes coding for beta-structural proteins-polypeptides, where amino acids with similar physical-chemical properties occupy symmetrical positions. A stochastic model of evolution of polynucleotide sequences has been used for analysis of inverted repeats. The modelling demonstrated that only limiting of sequences (uneven frequencies of used codons) is enough for arising of nonrandom inverted repeats in genes.

A structural and functional comparison of gap junction channels composed of connexins and innexins.

PubMed

Skerrett, I Martha; Williams, Jamal B

2017-05-01

Methods such as electron microscopy and electrophysiology led to the understanding that gap junctions were dense arrays of channels connecting the intracellular environments within almost all animal tissues. The characteristics of gap junctions were remarkably similar in preparations from phylogenetically diverse animals such as cnidarians and chordates. Although few studies directly compared them, minor differences were noted between gap junctions of vertebrates and invertebrates. For instance, a slightly wider gap was noted between cells of invertebrates and the spacing between invertebrate channels was generally greater. Connexins were identified as the structural component of vertebrate junctions in the 1980s and innexins as the structural component of pre-chordate junctions in the 1990s. Despite a lack of similarity in gene sequence, connexins and innexins are remarkably similar. Innexins and connexins have the same membrane topology and form intercellular channels that play a variety of tissue- and temporally specific roles. Both protein types oligomerize to form large aqueous channels that allow the passage of ions and small metabolites and are regulated by factors such as pH, calcium, and voltage. Much more is currently known about the structure, function, and structure-function relationships of connexins. However, the innexin field is expanding. Greater knowledge of innexin channels will permit more detailed comparisons with their connexin-based counterparts, and provide insight into the ubiquitous yet specific roles of gap junctions. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 522-547, 2017. © 2016 The Authors Developmental Neurobiology Published by Wiley Periodicals, Inc.

Expression of virus-encoded proteinases: functional and structural similarities with cellular enzymes.

PubMed Central

Dougherty, W G; Semler, B L

1993-01-01

Many viruses express their genome, or part of their genome, initially as a polyprotein precursor that undergoes proteolytic processing. Molecular genetic analyses of viral gene expression have revealed that many of these processing events are mediated by virus-encoded proteinases. Biochemical activity studies and structural analyses of these viral enzymes reveal that they have remarkable similarities to cellular proteinases. However, the viral proteinases have evolved unique features that permit them to function in a cellular environment. In this article, the current status of plant and animal virus proteinases is described along with their role in the viral replication cycle. The reactions catalyzed by viral proteinases are not simple enzyme-substrate interactions; rather, the processing steps are highly regulated, are coordinated with other viral processes, and frequently involve the participation of other factors. Images PMID:8302216

Origin, distribution and 3D-modeling of Gr-EXPB1, an expansin from the potato cyst nematode Globodera rostochiensis.

PubMed

Kudla, Urszula; Qin, Ling; Milac, Adina; Kielak, Anna; Maissen, Cyril; Overmars, Hein; Popeijus, Herman; Roze, Erwin; Petrescu, Andrei; Smant, Geert; Bakker, Jaap; Helder, Johannes

2005-04-25

Southern analysis showed that Gr-EXPB1, a functional expansin from the potato cyst nematode Globodera rostochiensis, is member of a multigene family, and EST data suggest expansins to be present in other plant parasitic nematodes as well. Homology modeling predicted that Gr-EXPB1 domain 1 (D1) has a flat beta-barrel structure with surface-exposed aromatic rings, whereas the 3D structure of Gr-EXPB1-D2 was remarkably similar to plant expansins. Gr-EXPB1 shows highest sequence similarity to two extracellular proteins from saprophytic soil-inhabiting Actinobacteria, and includes a bacterial type II carbohydrate-binding module. These results support the hypothesis that a number of pathogenicity factors of cyst nematodes is of procaryotic origin and were acquired by horizontal gene transfer.

Capturing the DSM-5 Alternative Personality Disorder Model Traits in the Five-Factor Model's Nomological Net.

PubMed

Suzuki, Takakuni; Griffin, Sarah A; Samuel, Douglas B

2017-04-01

Several studies have shown structural and statistical similarities between the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) alternative personality disorder model and the Five-Factor Model (FFM). However, no study to date has evaluated the nomological network similarities between the two models. The relations of the Revised NEO Personality Inventory (NEO PI-R) and the Personality Inventory for DSM-5 (PID-5) with relevant criterion variables were examined in a sample of 336 undergraduate students (M age  = 19.4; 59.8% female). The resulting profiles for each instrument were statistically compared for similarity. Four of the five domains of the two models have highly similar nomological networks, with the exception being FFM Openness to Experience and PID-5 Psychoticism. Further probing of that pair suggested that the NEO PI-R domain scores obscured meaningful similarity between PID-5 Psychoticism and specific aspects and lower-order facets of Openness. The results support the notion that the DSM-5 alternative personality disorder model trait domains represent variants of the FFM domains. Similarities of Openness and Psychoticism domains were supported when the lower-order aspects and facets of Openness domain were considered. The findings support the view that the DSM-5 trait model represents an instantiation of the FFM. © 2015 Wiley Periodicals, Inc.

Factor Analysis of the Brazilian Version of UPPS Impulsive Behavior Scale

PubMed Central

Sediyama, Cristina Y. N.; Moura, Ricardo; Garcia, Marina S.; da Silva, Antonio G.; Soraggi, Carolina; Neves, Fernando S.; Albuquerque, Maicon R.; Whiteside, Setephen P.; Malloy-Diniz, Leandro F.

2017-01-01

Objective: To examine the internal consistency and factor structure of the Brazilian adaptation of the UPPS Impulsive Behavior Scale. Methods: UPPS is a self-report scale composed by 40 items assessing four factors of impulsivity: (a) urgency, (b) lack of premeditation; (c) lack of perseverance; (d) sensation seeking. In the present study 384 participants (278 women and 106 men), who were recruited from schools, universities, leisure centers and workplaces fulfilled the UPPS scale. An exploratory factor analysis was performed by using Varimax factor rotation and Kaiser Normalization, and we also conducted two confirmatory analyses to test the independency of the UPPS components found in previous analysis. Results: Results showed a decrease in mean UPPS total scores with age and this analysis showed that the youngest participants (below 30 years) scored significantly higher than the other groups over 30 years. No difference in gender was found. Cronbach’s alpha, results indicated satisfactory values for all subscales, with similar high values for the subscales and confirmatory factor analysis indexes also indicated a poor model fit. The results of two exploratory factor analysis were satisfactory. Conclusion: Our results showed that the Portuguese version has the same four-factor structure of the original and previous translations of the UPPS. PMID:28484414

Population genomic analysis suggests strong influence of river network on spatial distribution of genetic variation in invasive saltcedar across the southwestern United States

USGS Publications Warehouse

Lee, Soo-Rang; Jo, Yeong-Seok; Park, Chan-Ho; Friedman, Jonathan M.; Olson, Matthew S.

2018-01-01

Understanding the complex influences of landscape and anthropogenic elements that shape the population genetic structure of invasive species provides insight into patterns of colonization and spread. The application of landscape genomics techniques to these questions may offer detailed, previously undocumented insights into factors influencing species invasions. We investigated the spatial pattern of genetic variation and the influences of landscape factors on population similarity in an invasive riparian shrub, saltcedar (Tamarix L.) by analysing 1,997 genomewide SNP markers for 259 individuals from 25 populations collected throughout the southwestern United States. Our results revealed a broad-scale spatial genetic differentiation of saltcedar populations between the Colorado and Rio Grande river basins and identified potential barriers to population similarity along both river systems. River pathways most strongly contributed to population similarity. In contrast, low temperature and dams likely served as barriers to population similarity. We hypothesize that large-scale geographic patterns in genetic diversity resulted from a combination of early introductions from distinct populations, the subsequent influence of natural selection, dispersal barriers and founder effects during range expansion.

Influence of Interspecific Competition and Landscape Structure on Spatial Homogenization of Avian Assemblages

PubMed Central

Robertson, Oliver J.; McAlpine, Clive; House, Alan; Maron, Martine

2013-01-01

Human-induced biotic homogenization resulting from landscape change and increased competition from widespread generalists or ‘winners’, is widely recognized as a global threat to biodiversity. However, it remains unclear what aspects of landscape structure influence homogenization. This paper tests the importance of interspecific competition and landscape structure, for the spatial homogeneity of avian assemblages within a fragmented agricultural landscape of eastern Australia. We used field observations of the density of 128 diurnal bird species to calculate taxonomic and functional similarity among assemblages. We then examined whether taxonomic and functional similarity varied with patch type, the extent of woodland habitat, land-use intensity, habitat subdivision, and the presence of Manorina colonies (a competitive genus of honeyeaters). We found the presence of a Manorina colony was the most significant factor positively influencing both taxonomic and functional similarity of bird assemblages. Competition from members of this widespread genus of native honeyeater, rather than landscape structure, was the main cause of both taxonomic and functional homogenization. These species have not recently expanded their range, but rather have increased in density in response to agricultural landscape change. The negative impacts of Manorina honeyeaters on assemblage similarity were most pronounced in landscapes of moderate land-use intensity. We conclude that in these human-modified landscapes, increased competition from dominant native species, or ‘winners’, can result in homogeneous avian assemblages and the loss of specialist species. These interacting processes make biotic homogenization resulting from land-use change a global threat to biodiversity in modified agro-ecosystems. PMID:23724136

The Organizational Health of Urban Elementary Schools: School Health and Teacher Functioning.

PubMed

Mehta, Tara G; Atkins, Marc S; Frazier, Stacy L

2013-09-01

This study examined the factor structure of the Organizational Health Inventory-Elementary version (OHI-E; Hoy, Tarter, & Kottkamp, 1991) in a sample of 203 teachers working in 19 high-poverty, urban schools and the association of organizational school health with teacher efficacy, teacher stress, and job satisfaction. Results indicated a similar factor structure of the OHI-E as compared with the population of schools in the original sample (Hoy et al., 1991), and that specific components of organizational health, such as a positive learning environment, are associated with teacher efficacy, stress, and satisfaction. Overall, teachers' relations with their peers, their school leadership, and their students appear especially critical in high-poverty, urban schools. Recommendations for research and practice related to improving high-poverty, urban schools are presented.

The Organizational Health of Urban Elementary Schools: School Health and Teacher Functioning

PubMed Central

Mehta, Tara G.; Atkins, Marc S.; Frazier, Stacy L.

2013-01-01

This study examined the factor structure of the Organizational Health Inventory-Elementary version (OHI-E; Hoy, Tarter, & Kottkamp, 1991) in a sample of 203 teachers working in 19 high-poverty, urban schools and the association of organizational school health with teacher efficacy, teacher stress, and job satisfaction. Results indicated a similar factor structure of the OHI-E as compared with the population of schools in the original sample (Hoy et al., 1991), and that specific components of organizational health, such as a positive learning environment, are associated with teacher efficacy, stress, and satisfaction. Overall, teachers’ relations with their peers, their school leadership, and their students appear especially critical in high-poverty, urban schools. Recommendations for research and practice related to improving high-poverty, urban schools are presented. PMID:23935763

Pre-Test Analysis Predictions for the Shell Buckling Knockdown Factor Checkout Tests - TA01 and TA02

NASA Technical Reports Server (NTRS)

Thornburgh, Robert P.; Hilburger, Mark W.

2011-01-01

This report summarizes the pre-test analysis predictions for the SBKF-P2-CYL-TA01 and SBKF-P2-CYL-TA02 shell buckling tests conducted at the Marshall Space Flight Center (MSFC) in support of the Shell Buckling Knockdown Factor (SBKF) Project, NASA Engineering and Safety Center (NESC) Assessment. The test article (TA) is an 8-foot-diameter aluminum-lithium (Al-Li) orthogrid cylindrical shell with similar design features as that of the proposed Ares-I and Ares-V barrel structures. In support of the testing effort, detailed structural analyses were conducted and the results were used to monitor the behavior of the TA during the testing. A summary of predicted results for each of the five load sequences is presented herein.

Analysis of local bond-orientational order for liquid gallium at ambient pressure: Two types of cluster structures.

PubMed

Chen, Lin-Yuan; Tang, Ping-Han; Wu, Ten-Ming

2016-07-14

In terms of the local bond-orientational order (LBOO) parameters, a cluster approach to analyze local structures of simple liquids was developed. In this approach, a cluster is defined as a combination of neighboring seeds having at least nb local-orientational bonds and their nearest neighbors, and a cluster ensemble is a collection of clusters with a specified nb and number of seeds ns. This cluster analysis was applied to investigate the microscopic structures of liquid Ga at ambient pressure (AP). The liquid structures studied were generated through ab initio molecular dynamics simulations. By scrutinizing the static structure factors (SSFs) of cluster ensembles with different combinations of nb and ns, we found that liquid Ga at AP contained two types of cluster structures, one characterized by sixfold orientational symmetry and the other showing fourfold orientational symmetry. The SSFs of cluster structures with sixfold orientational symmetry were akin to the SSF of a hard-sphere fluid. On the contrary, the SSFs of cluster structures showing fourfold orientational symmetry behaved similarly as the anomalous SSF of liquid Ga at AP, which is well known for exhibiting a high-q shoulder. The local structures of a highly LBOO cluster whose SSF displayed a high-q shoulder were found to be more similar to the structure of β-Ga than those of other solid phases of Ga. More generally, the cluster structures showing fourfold orientational symmetry have an inclination to resemble more to β-Ga.

Non-Rigid Structure Estimation in Trajectory Space from Monocular Vision

PubMed Central

Wang, Yaming; Tong, Lingling; Jiang, Mingfeng; Zheng, Junbao

2015-01-01

In this paper, the problem of non-rigid structure estimation in trajectory space from monocular vision is investigated. Similar to the Point Trajectory Approach (PTA), based on characteristic points’ trajectories described by a predefined Discrete Cosine Transform (DCT) basis, the structure matrix was also calculated by using a factorization method. To further optimize the non-rigid structure estimation from monocular vision, the rank minimization problem about structure matrix is proposed to implement the non-rigid structure estimation by introducing the basic low-rank condition. Moreover, the Accelerated Proximal Gradient (APG) algorithm is proposed to solve the rank minimization problem, and the initial structure matrix calculated by the PTA method is optimized. The APG algorithm can converge to efficient solutions quickly and lessen the reconstruction error obviously. The reconstruction results of real image sequences indicate that the proposed approach runs reliably, and effectively improves the accuracy of non-rigid structure estimation from monocular vision. PMID:26473863

Scientific literacy: Factor structure and gender differences

NASA Astrophysics Data System (ADS)

Manhart, James Joseph

The purpose of this study was to investigate the factor structure of scientific literacy and to document any gender differences with respect to each factor. Participants included 1139 students (574 females, 565 males) in grades 9 through 12 who were taking a science class at one of four Midwestern high schools. Based on National Science Education Standards, a 100 item multiple-choice test was constructed to assess scientific literacy. Confirmatory factor analysis of item parcels suggested a three factor model was the best way to explain the data resulting from the administration of this test. The factors were labeled constructs of science, abilities necessary to do scientific inquiry, and social aspects of science. Gender differences with respect to these factors were examined using analysis of variance procedures. Because differential enrollment in science classes could cause gender differences in grades 11 and 12, parallel analyses were conducted on the grades 9 and 10 subsample and the grades 11 and 12 subsample. However, the results of the two analyses were similar. The most consistent gender difference observed was that females performed better than males on the social aspects of science factor. Males tended to perform better than females on the constructs of science factor, although no consistent gender difference was noted for items dealing with life science. With respect to the abilities necessary to do scientific inquiry factor, females tended to perform better than males in grades 9 and 10, while no consistent gender difference was observed in grades 11 and 12. Gender differences were also examined using the Mantel-Haenszel procedure to flag individual items that functioned differently for females and males of the same ability. Twelve items were flagged for grades 9 and 10 (8 in favor of females, 4 in favor of males). Fourteen items were flagged for grades 11 and 12 (7 in favor of females, 7 in favor of males). All of the flagged items exhibited only small to moderate differential item functioning (DIF). Only three items were similarly flagged in both subsamples, one item from each factor.

A Latent Variable Approach to Determining the Structure of Executive Function in Preschool Children

ERIC Educational Resources Information Center

Miller, Michael R.; Giesbrecht, Gerald F.; Muller, Ulrich; McInerney, Robert J.; Kerns, Kimberly A.

2012-01-01

The composition of executive function (EF) in preschool children was examined using confirmatory factor analysis (CFA). A sample of 129 children between 3 and 5 years of age completed a battery of EF tasks. Using performance indicators of working memory and inhibition similar to previous CFA studies with preschoolers, we replicated a unitary EF…

Methanogen Diversity in Indigenous and Introduced Ruminant Species on the Tibetan Plateau

PubMed Central

Huang, Xiao Dan; Martinez-Fernandez, Gonzalo; Padmanabha, Jagadish; Long, Ruijun; Denman, Stuart E.; McSweeney, Christopher S.

2016-01-01

Host factors are regarded as important in shaping the archaeal community in the rumen but few controlled studies have been performed to demonstrate this across host species under the same environmental conditions. A study was designed to investigate the structure of the methanogen community in the rumen of two indigenous (yak and Tibetan sheep) and two introduced domestic ruminant (cattle and crossbred sheep) species raised and fed under similar conditions on the high altitude Tibetan Plateau. The methylotrophic Methanomassiliicoccaceae was the predominant archaeal group in all animals even though Methanobrevibacter are usually present in greater abundance in ruminants globally. Furthermore, within the Methanomassiliicoccaceae family members from Mmc. group 10 and Mmc. group 4 were dominant in Tibetan Plateau ruminants compared to Mmc. group 12 found to be highest in other ruminants studied. Small ruminants presented the highest number of sequences that belonged to Methanomassiliicoccaceae compared to the larger ruminants. Although the methanogen community structure was different among the ruminant species, there were striking similarities between the animals in this environment. This indicates that factors such as the extreme environmental conditions and diet on the Tibetan Plateau might have a greater impact on rumen methanogen community compared to host differences. PMID:27274707

The structure of intelligence in children and adults with high functioning autism

PubMed Central

Goldstein, Gerald; Allen, Daniel N.; Minshew, Nancy J.; Williams, Diane L.; Volkmar, Fred; Klin, Ami; Schultz, Robert J.

2011-01-01

Confirmatory factor analyses of the traditional 11 subtests of the Wechsler child and adult intelligence scales were accomplished for 137 children and 118 adults with high functioning autism (HFA) and for comparable age groups from the standardization samples contained in the Wechsler manuals. The objective was determining whether HFA groups produced similar best fitting models to those found in the normative samples or formed a separate “social intelligence” factor. Four-factor models incorporating a “social intelligence” factor provided the best fit in both the autism and normative, but the subtest intercorrelations were generally lower in the autism samples. Findings were interpreted in terms of underconnectivity or reduced communication among brain regions in autism. PMID:18444708

Glucan Binding Protein C of Streptococcus mutans Mediates both Sucrose-Independent and Sucrose-Dependent Adherence.

PubMed

Mieher, Joshua L; Larson, Matthew R; Schormann, Norbert; Purushotham, Sangeetha; Wu, Ren; Rajashankar, Kanagalaghatta R; Wu, Hui; Deivanayagam, Champion

2018-07-01

The high-resolution structure of glucan binding protein C (GbpC) at 1.14 Å, a sucrose-dependent virulence factor of the dental caries pathogen Streptococcus mutans , has been determined. GbpC shares not only structural similarities with the V regions of AgI/II and SspB but also functional adherence to salivary agglutinin (SAG) and its scavenger receptor cysteine-rich domains (SRCRs). This is not only a newly identified function for GbpC but also an additional fail-safe binding mechanism for S. mutans Despite the structural similarities with S. mutans antigen I/II (AgI/II) and SspB of Streptococcus gordonii , GbpC remains unique among these surface proteins in its propensity to adhere to dextran/glucans. The complex crystal structure of GbpC with dextrose (β-d-glucose; Protein Data Bank ligand BGC) highlights exclusive structural features that facilitate this interaction with dextran. Targeted deletion mutant studies on GbpC's divergent loop region in the vicinity of a highly conserved calcium binding site confirm its role in biofilm formation. Finally, we present a model for adherence to dextran. The structure of GbpC highlights how artfully microbes have engineered the lectin-like folds to broaden their functional adherence repertoire. Copyright © 2018 American Society for Microbiology.

Biomechanical and Structural Features of CS2 Fimbriae of Enterotoxigenic Escherichia coli

PubMed Central

Mortezaei, Narges; Singh, Bhupender; Zakrisson, Johan; Bullitt, Esther; Andersson, Magnus

2015-01-01

Enterotoxigenic Escherichia coli (ETEC) are a major cause of diarrhea worldwide, and infection of children in under-developed countries often leads to high mortality rates. Isolated ETEC expresses a plethora of colonization factors (fimbriae/pili), of which CFA/I and CFA/II, which are assembled via the alternate chaperone pathway (ACP), are among the most common. Fimbriae are filamentous structures whose shafts are primarily composed of helically arranged single pilin-protein subunits, with a unique biomechanical ability to unwind and rewind. A sustained ETEC infection, under adverse conditions of dynamic shear forces, is primarily attributed to this biomechanical feature of ETEC fimbriae. Recent understanding about the role of fimbriae as virulence factors points to an evolutionary adaptation of their structural and biomechanical features. In this work, we investigated the biophysical properties of CS2 fimbriae from the CFA/II group. Homology modeling of its major structural subunit, CotA, reveals structural clues related to the niche in which they are expressed. Using optical-tweezers force spectroscopy, we found that CS2 fimbriae unwind at a constant force of 10 pN and have a corner velocity (i.e., the velocity at which the force required for unwinding rises exponentially with increased speed) of 1300 nm/s. The biophysical properties of CS2 fimbriae assessed in this work classify them into a low-force unwinding group of fimbriae together with the CFA/I and CS20 fimbriae expressed by ETEC strains. The three fimbriae are expressed by ETEC, colonize in similar gut environments, and exhibit similar biophysical features, but differ in their biogenesis. Our observation suggests that the environment has a strong impact on the biophysical characteristics of fimbriae expressed by ETEC. PMID:26153701

Scoring of Side-Chain Packings: An Analysis of Weight Factors and Molecular Dynamics Structures.

PubMed

Colbes, Jose; Aguila, Sergio A; Brizuela, Carlos A

2018-02-26

The protein side-chain packing problem (PSCPP) is a central task in computational protein design. The problem is usually modeled as a combinatorial optimization problem, which consists of searching for a set of rotamers, from a given rotamer library, that minimizes a scoring function (SF). The SF is a weighted sum of terms, that can be decomposed in physics-based and knowledge-based terms. Although there are many methods to obtain approximate solutions for this problem, all of them have similar performances and there has not been a significant improvement in recent years. Studies on protein structure prediction and protein design revealed the limitations of current SFs to achieve further improvements for these two problems. In the same line, a recent work reported a similar result for the PSCPP. In this work, we ask whether or not this negative result regarding further improvements in performance is due to (i) an incorrect weighting of the SFs terms or (ii) the constrained conformation resulting from the protein crystallization process. To analyze these questions, we (i) model the PSCPP as a bi-objective combinatorial optimization problem, optimizing, at the same time, the two most important terms of two SFs of state-of-the-art algorithms and (ii) performed a preprocessing relaxation of the crystal structure through molecular dynamics to simulate the protein in the solvent and evaluated the performance of these two state-of-the-art SFs under these conditions. Our results indicate that (i) no matter what combination of weight factors we use the current SFs will not lead to better performances and (ii) the evaluated SFs will not be able to improve performance on relaxed structures. Furthermore, the experiments revealed that the SFs and the methods are biased toward crystallized structures.

Crystal Structure of Swine Vesicular Disease Virus and Implications for Host Adaptation

PubMed Central

Fry, Elizabeth E.; Knowles, Nick J.; Newman, John W. I.; Wilsden, Ginette; Rao, Zihe; King, Andrew M. Q.; Stuart, David I.

2003-01-01

Swine vesicular disease virus (SVDV) is an Enterovirus of the family Picornaviridae that causes symptoms indistinguishable from those of foot-and-mouth disease virus. Phylogenetic studies suggest that it is a recently evolved genetic sublineage of the important human pathogen coxsackievirus B5 (CBV5), and in agreement with this, it has been shown to utilize the coxsackie and adenovirus receptor (CAR) for cell entry. The 3.0-Å crystal structure of strain UK/27/72 SVDV (highly virulent) reveals the expected similarity in core structure to those of other picornaviruses, showing most similarity to the closest available structure to CBV5, that of coxsackievirus B3 (CBV3). Features that help to cement together and rigidify the protein subunits are extended in this virus, perhaps explaining its extreme tolerance of environmental factors. Using the large number of capsid sequences available for both SVDV and CBV5, we have mapped the amino acid substitutions that may have occurred during the supposed adaptation of SVDV to a new host onto the structure of SVDV and a model of the SVDV/CAR complex generated by reference to the cryo-electron microscopy-visualized complex of CBV3 and CAR. The changes fall into three clusters as follows: one lines the fivefold pore, a second maps to the CAR-binding site and partially overlaps the site for decay accelerating factor (DAF) to bind to echovirus 7 (ECHO7), and the third lies close to the fivefold axis, where the low-density lipoprotein receptor binds to the minor group of rhinoviruses. Later changes in SVDV (post-1971) map to the first two clusters and may, by optimizing recognition of a pig CAR and/or DAF homologue, have improved the adaptation of the virus to pigs. PMID:12692248

Medium range order and structural relaxation in As–Se network glasses through FSDP analysis

DOE PAGES

Golovchak, R.; Lucas, P.; Oelgoetz, J.; ...

2015-01-13

We performed synchrotron X-ray diffraction and neutron scattering studies on As-Se glasses in two states: as-prepared (rejuvenated) and aged for similar to 27 years. The first sharp diffraction peak (FSDP) obtained from the structure factor data as a function of composition and temperature indicates that the cooperative processes that are responsible for structural relaxation do not affect FSDP. The results are correlated with the composition dependence of the complex heat capacity of the glasses and concentration of different structural fragments in the glass network. Furthermore, the comparison of structural information shows that density fluctuations, which were thought previously to havemore » a significant contribution to FSDP, have much smaller effect than the cation-cation correlations, presence of ordered structural fragments or cage molecules.« less

Molecular Basis for the Recognition and Cleavages of IGF-II, TGF-[alpha], and Amylin by Human Insulin-Degrading Enzyme

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

Guo, Qing; Manolopoulou, Marika; Bian, Yao

2010-02-11

Insulin-degrading enzyme (IDE) is involved in the clearance of many bioactive peptide substrates, including insulin and amyloid-{beta}, peptides vital to the development of diabetes and Alzheimer's disease, respectively. IDE can also rapidly degrade hormones that are held together by intramolecular disulfide bond(s) without their reduction. Furthermore, IDE exhibits a remarkable ability to preferentially degrade structurally similar peptides such as the selective degradation of insulin-like growth factor (IGF)-II and transforming growth factor-{alpha} (TGF-{alpha}) over IGF-I and epidermal growth factor, respectively. Here, we used high-accuracy mass spectrometry to identify the cleavage sites of human IGF-II, TGF-{alpha}, amylin, reduced amylin, and amyloid-{beta} bymore » human IDE. We also determined the structures of human IDE-IGF-II and IDE-TGF-{alpha} at 2.3 {angstrom} and IDE-amylin at 2.9 {angstrom}. We found that IDE cleaves its substrates at multiple sites in a biased stochastic manner. Furthermore, the presence of a disulfide bond in amylin allows IDE to cut at an additional site in the middle of the peptide (amino acids 18-19). Our amylin-bound IDE structure offers insight into how the structural constraint from a disulfide bond in amylin can alter IDE cleavage sites. Together with NMR structures of amylin and the IGF and epidermal growth factor families, our work also reveals the structural basis of how the high dipole moment of substrates complements the charge distribution of the IDE catalytic chamber for the substrate selectivity. In addition, we show how the ability of substrates to properly anchor their N-terminus to the exosite of IDE and undergo a conformational switch upon binding to the catalytic chamber of IDE can also contribute to the selective degradation of structurally related growth factors.« less

Reliability and Validity of the Telephone-Based eHealth Literacy Scale Among Older Adults: Cross-Sectional Survey.

PubMed

Stellefson, Michael; Paige, Samantha R; Tennant, Bethany; Alber, Julia M; Chaney, Beth H; Chaney, Don; Grossman, Suzanne

2017-10-26

Only a handful of studies have examined reliability and validity evidence of scores produced by the 8-item eHealth literacy Scale (eHEALS) among older adults. Older adults are generally more comfortable responding to survey items when asked by a real person rather than by completing self-administered paper-and-pencil or online questionnaires. However, no studies have explored the psychometrics of this scale when administered to older adults over the telephone. The objective of our study was to examine the reliability and internal structure of eHEALS data collected from older adults aged 50 years or older responding to items over the telephone. Respondents (N=283) completed eHEALS as part of a cross-sectional landline telephone survey. Exploratory structural equation modeling (E-SEM) analyses examined model fit of eHEALS scores with 1-, 2-, and 3-factor structures. Subsequent analyses based on the partial credit model explored the internal structure of eHEALS data. Compared with 1- and 2-factor models, the 3-factor eHEALS structure showed the best global E-SEM model fit indices (root mean square error of approximation=.07; comparative fit index=1.0; Tucker-Lewis index=1.0). Nonetheless, the 3 factors were highly correlated (r range .36 to .65). Item analyses revealed that eHEALS items 2 through 5 were overfit to a minor degree (mean square infit/outfit values <1.0; t statistics less than -2.0), but the internal structure of Likert scale response options functioned as expected. Overfitting eHEALS items (2-5) displayed a similar degree of information for respondents at similar points on the latent continuum. Test information curves suggested that eHEALS may capture more information about older adults at the higher end of the latent continuum (ie, those with high eHealth literacy) than at the lower end of the continuum (ie, those with low eHealth literacy). Item reliability (value=.92) and item separation (value=11.31) estimates indicated that eHEALS responses were reliable and stable. Results support administering eHEALS over the telephone when surveying older adults regarding their use of the Internet for health information. eHEALS scores best captured 3 factors (or subscales) to measure eHealth literacy in older adults; however, statistically significant correlations between these 3 factors suggest an overarching unidimensional structure with 3 underlying dimensions. As older adults continue to use the Internet more frequently to find and evaluate health information, it will be important to consider modifying the original eHEALS to adequately measure societal shifts in online health information seeking among aging populations. ©Michael Stellefson, Samantha R Paige, Bethany Tennant, Julia M Alber, Beth H Chaney, Don Chaney, Suzanne Grossman. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 26.10.2017.

Maximum Likelihood Factor Analysis of the Effects of Chronic Centrifugation on the Structural Development of the Musculoskeletal System of the Rat

NASA Technical Reports Server (NTRS)

Amtmann, E.; Kimura, T.; Oyama, J.; Doden, E.; Potulski, M.

1979-01-01

At the age of 30 days female Sprague-Dawley rats were placed on a 3.66 m radius centrifuge and subsequently exposed almost continuously for 810 days to either 2.76 or 4.15 G. An age-matched control group of rats was raised near the centrifuge facility at earth gravity. Three further control groups of rats were obtained from the animal colony and sacrificed at the age of 34, 72 and 102 days. A total of 16 variables were simultaneously factor analyzed by maximum-likelihood extraction routine and the factor loadings presented after-rotation to simple structure by a varimax rotation routine. The variables include the G-load, age, body mass, femoral length and cross-sectional area, inner and outer radii, density and strength at the mid-length of the femur, dry weight of gluteus medius, semimenbranosus and triceps surae muscles. Factor analyses on A) all controls, B) all controls and the 2.76 G group, and C) all controls and centrifuged animals, produced highly similar loading structures of three common factors which accounted for 74%, 68% and 68%. respectively, of the total variance. The 3 factors were interpreted as: 1. An age and size factor which stimulates the growth in length and diameter and increases the density and strength of the femur. This factor is positively correlated with G-load but is also active in the control animals living at earth gravity. 2. A growth inhibition factor which acts on body size, femoral length and on both the outer and inner radius at mid-length of the femur. This factor is intensified by centrifugation.

Confirmatory factor analysis of 2 versions of the Brief Pain Inventory in an ambulatory population indicates that sleep interference should be interpreted separately.

PubMed

Walton, David M; Putos, Joseph; Beattie, Tyler; MacDermid, Joy C

2016-07-01

The Brief Pain Inventory (BPI-SF) is a widely-used generic pain interference scale, however its factor structure remains unclear. An expanded 10-item version of the Interference subscale has been proposed, but the additional value of the 3 extra items has not been rigorously evaluated. The purpose of this study was to evaluate and contrast the factorial and concurrent validity of the original 7-item and 10-item versions of the BPI-SF in a large heterogeneous sample of patients with chronic pain. Exploratory and confirmatory factor analyses were conducted on independent subsets of the sample, and concurrent correlations with scales capturing similar constructs were evaluated. Two independent exploratory factor analyses (n=500 each) supported a single interference factor in both the 7- and 10-item versions, while confirmatory factor analysis (N=1000) suggested that a 2-factor structure (Physical and Affective) provided better fit. A 3-factor model, where sleep interference was the third factor, improved in model fit further. There was no significant difference in model fit between the 7- and 10-item versions. Concurrent associations with measures of general health, pain intensity and pain-related cognitions were all in the anticipated direction and magnitude and were not different by version of the BPI-SF. The addition of 3 extra items to the original 7-item Interference subscale of the BPI-SF did not improve psychometric properties. The combined results lead us to endorse a 3-factor structure (Physical, Affective, and Sleep Interference) as the more statistically and conceptually sound option. Copyright © 2016 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Developing the Stroke Exercise Preference Inventory (SEPI)

PubMed Central

Bonner, Nicholas S.; O’Halloran, Paul D.; Bernhardt, Julie; Cumming, Toby B.

2016-01-01

Background Physical inactivity is highly prevalent after stroke, increasing the risk of poor health outcomes including recurrent stroke. Tailoring of exercise programs to individual preferences can improve adherence, but no tools exist for this purpose in stroke. Methods We identified potential questionnaire items for establishing exercise preferences via: (i) our preliminary Exercise Preference Questionnaire in stroke, (ii) similar tools used in other conditions, and (iii) expert panel consultations. The resulting 35-item questionnaire (SEPI-35) was administered to stroke survivors, along with measures of disability, depression, anxiety, fatigue and self-reported physical activity. Exploratory factor analysis was used to identify a factor structure in exercise preferences, providing a framework for item reduction. Associations between exercise preferences and personal characteristics were analysed using multivariable regression. Results A group of 134 community-dwelling stroke survivors (mean age 64.0, SD 13.3) participated. Analysis of the SEPI-35 identified 7 exercise preference factors (Supervision-support, Confidence-challenge, Health-wellbeing, Exercise context, Home-alone, Similar others, Music-TV). Item reduction processes yielded a 13-item version (SEPI-13); in analysis of this version, the original factor structure was maintained. Lower scores on Confidence-challenge were significantly associated with disability (p = 0.002), depression (p = 0.001) and fatigue (p = 0.001). Self-reported barriers to exercise were particularly prevalent in those experiencing fatigue and anxiety. Conclusions The SEPI-13 is a brief instrument that allows assessment of exercise preferences and barriers in the stroke population. This new tool can be employed by health professionals to inform the development of individually tailored exercise interventions. PMID:27711242

The social and community opportunities profile social inclusion measure: Structural equivalence and differential item functioning in community mental health residents in Hong Kong and the United Kingdom.

PubMed

Huxley, Peter John; Chan, Kara; Chiu, Marcus; Ma, Yanni; Gaze, Sarah; Evans, Sherrill

2016-03-01

China's future major health problem will be the management of chronic diseases - of which mental health is a major one. An instrument is needed to measure mental health inclusion outcomes for mental health services in Hong Kong and mainland China as they strive to promote a more inclusive society for their citizens and particular disadvantaged groups. To report on the analysis of structural equivalence and item differentiation in two mentally unhealthy and one healthy sample in the United Kingdom and Hong Kong. The mental health sample in Hong Kong was made up of non-governmental organisation (NGO) referrals meeting the selection/exclusion criteria (being well enough to be interviewed, having a formal psychiatric diagnosis and living in the community). A similar sample in the United Kingdom meeting the same selection criteria was obtained from a community mental health organisation, equivalent to the NGOs in Hong Kong. Exploratory factor analysis and logistic regression were conducted. The single-variable, self-rated 'overall social inclusion' differs significantly between all of the samples, in the way we would expect from previous research, with the healthy population feeling more included than the serious mental illness (SMI) groups. In the exploratory factor analysis, the first two factors explain between a third and half of the variance, and the single variable which enters into all the analyses in the first factor is having friends to visit the home. All the regression models were significant; however, in Hong Kong sample, only one-fifth of the total variance is explained. The structural findings imply that the social and community opportunities profile-Chinese version (SCOPE-C) gives similar results when applied to another culture. As only one-fifth of the variance of 'overall inclusion' was explained in the Hong Kong sample, it may be that the instrument needs to be refined using different or additional items within the structural domains of inclusion. © The Author(s) 2015.

In silico characterization and analysis of RTBP1 and NgTRF1 protein through MD simulation and molecular docking - A comparative study.

PubMed

Mukherjee, Koel; Pandey, Dev Mani; Vidyarthi, Ambarish Saran

2015-02-06

Gaining access to sequence and structure information of telomere binding proteins helps in understanding the essential biological processes involve in conserved sequence specific interaction between DNA and the proteins. Rice telomere binding protein (RTBP1) and Nicotiana glutinosa telomere repeat binding factor (NgTRF1) are helix turn helix motif type of proteins that plays role in telomeric DNA protection and length regulation. Both the proteins share same type of domain but till now there is very less communication on the in silico studies of these complete proteins.Here we intend to do a comparative study between two proteins through modeling of the complete proteins, physiochemical characterization, MD simulation and DNA-protein docking. I-TASSER and CLC protein work bench was performed to find out the protein 3D structure as well as the different parameters to characterize the proteins. MD simulation was completed by GROMOS forcefield of GROMACS for 10 ns of time stretch. The simulated 3D structures were docked with template DNA (3D DNA modeled through 3D-DART) of TTTAGGG conserved sequence motif using HADDOCK web server.Digging up all the facts about the proteins it was reveled that around 120 amino acids in the tail part was showing a good sequence similarity between the proteins. Molecular modeling, sequence characterization and secondary structure prediction also indicates the similarity between the protein's structure and sequence. The result of MD simulation highlights on the RMSD, RMSF, Rg, PCA and Energy plots which also conveys the similar type of motional behavior between them. The best complex formation for both the proteins in docking result also indicates for the first interaction site which is mainly the helix3 region of the DNA binding domain. The overall computational analysis reveals that RTBP1 and NgTRF1 proteins display good amount of similarity in their physicochemical properties, structure, dynamics and binding mode.

In Silico Characterization and Analysis of RTBP1 and NgTRF1 Protein Through MD Simulation and Molecular Docking: A Comparative Study.

PubMed

Mukherjee, Koel; Pandey, Dev Mani; Vidyarthi, Ambarish Saran

2015-09-01

Gaining access to sequence and structure information of telomere-binding proteins helps in understanding the essential biological processes involve in conserved sequence-specific interaction between DNA and the proteins. Rice telomere-binding protein (RTBP1) and Nicotiana glutinosa telomere repeat binding factor (NgTRF1) are helix-turn-helix motif type of proteins that plays role in telomeric DNA protection and length regulation. Both the proteins share same type of domain, but till now there is very less communication on the in silico studies of these complete proteins. Here we intend to do a comparative study between two proteins through modeling of the complete proteins, physiochemical characterization, MD simulation and DNA-protein docking. I-TASSER and CLC protein work bench was performed to find out the protein 3D structure as well as the different parameters to characterize the proteins. MD simulation was completed by GROMOS forcefield of GROMACS for 10 ns of time stretch. The simulated 3D structures were docked with template DNA (3D DNA modeled through 3D-DART) of TTTAGGG conserved sequence motif using HADDOCK Web server. By digging up all the facts about the proteins, it was revealed that around 120 amino acids in the tail part were showing a good sequence similarity between the proteins. Molecular modeling, sequence characterization and secondary structure prediction also indicate the similarity between the protein's structure and sequence. The result of MD simulation highlights on the RMSD, RMSF, Rg, PCA and energy plots which also conveys the similar type of motional behavior between them. The best complex formation for both the proteins in docking result also indicates for the first interaction site which is mainly the helix3 region of the DNA-binding domain. The overall computational analysis reveals that RTBP1 and NgTRF1 proteins display good amount of similarity in their physicochemical properties, structure, dynamics and binding mode.

Super-resolution biomolecular crystallography with low-resolution data.

PubMed

Schröder, Gunnar F; Levitt, Michael; Brunger, Axel T

2010-04-22

X-ray diffraction plays a pivotal role in the understanding of biological systems by revealing atomic structures of proteins, nucleic acids and their complexes, with much recent interest in very large assemblies like the ribosome. As crystals of such large assemblies often diffract weakly (resolution worse than 4 A), we need methods that work at such low resolution. In macromolecular assemblies, some of the components may be known at high resolution, whereas others are unknown: current refinement methods fail as they require a high-resolution starting structure for the entire complex. Determining the structure of such complexes, which are often of key biological importance, should be possible in principle as the number of independent diffraction intensities at a resolution better than 5 A generally exceeds the number of degrees of freedom. Here we introduce a method that adds specific information from known homologous structures but allows global and local deformations of these homology models. Our approach uses the observation that local protein structure tends to be conserved as sequence and function evolve. Cross-validation with R(free) (the free R-factor) determines the optimum deformation and influence of the homology model. For test cases at 3.5-5 A resolution with known structures at high resolution, our method gives significant improvements over conventional refinement in the model as monitored by coordinate accuracy, the definition of secondary structure and the quality of electron density maps. For re-refinements of a representative set of 19 low-resolution crystal structures from the Protein Data Bank, we find similar improvements. Thus, a structure derived from low-resolution diffraction data can have quality similar to a high-resolution structure. Our method is applicable to the study of weakly diffracting crystals using X-ray micro-diffraction as well as data from new X-ray light sources. Use of homology information is not restricted to X-ray crystallography and cryo-electron microscopy: as optical imaging advances to subnanometre resolution, it can use similar tools.

Metamorphic Proteins: Emergence of Dual Protein Folds from One Primary Sequence.

PubMed

Lella, Muralikrishna; Mahalakshmi, Radhakrishnan

2017-06-20

Every amino acid exhibits a different propensity for distinct structural conformations. Hence, decoding how the primary amino acid sequence undergoes the transition to a defined secondary structure and its final three-dimensional fold is presently considered predictable with reasonable certainty. However, protein sequences that defy the first principles of secondary structure prediction (they attain two different folds) have recently been discovered. Such proteins, aptly named metamorphic proteins, decrease the conformational constraint by increasing flexibility in the secondary structure and thereby result in efficient functionality. In this review, we discuss the major factors driving the conformational switch related both to protein sequence and to structure using illustrative examples. We discuss the concept of an evolutionary transition in sequence and structure, the functional impact of the tertiary fold, and the pressure of intrinsic and external factors that give rise to metamorphic proteins. We mainly focus on the major components of protein architecture, namely, the α-helix and β-sheet segments, which are involved in conformational switching within the same or highly similar sequences. These chameleonic sequences are widespread in both cytosolic and membrane proteins, and these folds are equally important for protein structure and function. We discuss the implications of metamorphic proteins and chameleonic peptide sequences in de novo peptide design.

Virulence factor rtx in Legionella pneumophila, evidence suggesting it is a modular multifunctional protein.

PubMed

D'Auria, Giuseppe; Jiménez, Núria; Peris-Bondia, Francesc; Pelaz, Carmen; Latorre, Amparo; Moya, Andrés

2008-01-14

The repeats in toxin (Rtx) are an important pathogenicity factor involved in host cells invasion of Legionella pneumophila and other pathogenic bacteria. Its role in escaping the host immune system and cytotoxic activity is well known. Its repeated motives and modularity make Rtx a multifunctional factor in pathogenicity. The comparative analysis of rtx gene among 6 strains of L. pneumophila showed modularity in their structures. Among compared genomes, the N-terminal region of the protein presents highly dissimilar repeats with functionally similar domains. On the contrary, the C-terminal region is maintained with a fashionable modular configuration, which gives support to its proposed role in adhesion and pore formation. Despite the variability of rtx among the considered strains, the flanking genes are maintained in synteny and similarity. In contrast to the extracellular bacteria Vibrio cholerae, in which the rtx gene is highly conserved and flanking genes have lost synteny and similarity, the gene region coding for the Rtx toxin in the intracellular pathogen L. pneumophila shows a rapid evolution. Changes in the rtx could play a role in pathogenicity. The interplay of the Rtx toxin with host membranes might lead to the evolution of new variants that are able to escape host cell defences.

Breast Cancer Screening Beliefs Questionnaire: Psychometric properties assessment of the Arabic version.

PubMed

Kwok, Cannas; Endrawes, Gihane; Lee, Chun Fan

2016-02-01

The aim of the study was to report the psychometric properties of the Arabic version of the Breast Cancer Screening Beliefs Questionnaire (BCSBQ). A convenience sample of 251 Arabic-Australian women was recruited from a number of Arabic community organizations. Construct validity was examined by Cuzick's non-parametric test while Cronbach α was used to assess internal consistency reliability. Explanatory factor analysis was conducted to study the factor structure. The results indicated that the Arabic version of the BCSBQ had satisfactory validity and internal consistency. The Cronbach's alpha of the three subscales ranged between 0.810 and 0.93. The frequency of breast cancer screening practices (breast awareness, clinical breast-examination and mammography) were significantly associated with attitudes towards general health check-up and perceived barriers to mammographic screening. Exploratory factor analysis showed a similar fit for the hypothesized three-factor structure with our data set. The Arabic version of the BCBSQ is a culturally appropriate, valid and reliable instrument for assessing the beliefs, knowledge and attitudes to breast cancer and breast cancer screening practices among Arabic-Australian women. Copyright © 2015 Elsevier Ltd. All rights reserved.

Acetylcholine-Like Molecular Arrangement in Psychomimetic Anticholinergic Drugs

PubMed Central

Maayani, Saul; Weinstein, Harel; Cohen, Sasson; Sokolovsky, Mordechai

1973-01-01

A study of the relation between the psychotropic activity and the antagonism to acetylcholine observed for some heterocyclic amino esters and compounds of the phencyclidine series suggests some common molecular structural requirements for their properties. Criteria obtained from quantum mechanical calculations of acetylcholine-like molecules indicate that their molecular reactivity with the cholinergic receptor site follows a certain dynamic interaction pattern. This pattern suggests a certain molecular arrangement essential for the interaction, which is based on the electronic properties of the molecules and therefore remains valid for the evaluation of compounds which lack any apparent similarity to acetylcholine. This type of molecular arrangement is shown to be shared by both activators and inhibitors of the acetylcholine receptor discussed here, thus supporting the hypothesis of their binding to a common receptor. The differences in biological activity are attributed to the effect of molecular structural factors which are not commonly included in the molecular arrangement based on the active groups of acetylcholine. The role of such factors is revealed by a study of the observed differences in the cholinergic and psychomimetic activities of related pairs of isomers and enantiomers of the molecules investigated. Structural factors which interfere with the conformational changes occurring in the receptor protein induced by an activator are characterized through differences obtained by the comparative investigation of the activities of the agonist acetate and the antagonist benzilate amino esters of quinuclidine, tropine, and pseudotropine. The same factors are shown in studies of the phencyclidine series to contribute to the antagonism to acetylcholine activity that is closely related to the psychomimetic activity of these drugs in the central nervous system. Similarly, phencyclidine derivatives in which the characteristic acetylcholine-like molecular arrangement is modified by various substitutions are shown to loose both anticholinergic and psychotropic behavior. This close correlation is supported by the identification of molecular regions which will generate the proper molecular arrangement in local anesthetics and morphine, compounds which are known to be involved in cholinergic mechanisms. Images PMID:4522291

Insights into molecular plasticity in protein complexes from Trm9-Trm112 tRNA modifying enzyme crystal structure

PubMed Central

Létoquart, Juliette; van Tran, Nhan; Caroline, Vonny; Aleksandrov, Alexey; Lazar, Noureddine; van Tilbeurgh, Herman; Liger, Dominique; Graille, Marc

2015-01-01

Most of the factors involved in translation (tRNA, rRNA and proteins) are subject to post-transcriptional and post-translational modifications, which participate in the fine-tuning and tight control of ribosome and protein synthesis processes. In eukaryotes, Trm112 acts as an obligate activating platform for at least four methyltransferases (MTase) involved in the modification of 18S rRNA (Bud23), tRNA (Trm9 and Trm11) and translation termination factor eRF1 (Mtq2). Trm112 is then at a nexus between ribosome synthesis and function. Here, we present a structure-function analysis of the Trm9-Trm112 complex, which is involved in the 5-methoxycarbonylmethyluridine (mcm5U) modification of the tRNA anticodon wobble position and hence promotes translational fidelity. We also compare the known crystal structures of various Trm112-MTase complexes, highlighting the structural plasticity allowing Trm112 to interact through a very similar mode with its MTase partners, although those share less than 20% sequence identity. PMID:26438534

Structure of Radical-Induced Cell Death1 Hub Domain Reveals a Common αα-Scaffold for Disorder in Transcriptional Networks.

PubMed

Bugge, Katrine; Staby, Lasse; Kemplen, Katherine R; O'Shea, Charlotte; Bendsen, Sidsel K; Jensen, Mikael K; Olsen, Johan G; Skriver, Karen; Kragelund, Birthe B

2018-05-01

Communication within cells relies on a few protein nodes called hubs, which organize vast interactomes with many partners. Frequently, hub proteins are intrinsically disordered conferring multi-specificity and dynamic communication. Conversely, folded hub proteins may organize networks using disordered partners. In this work, the structure of the RST domain, a unique folded hub, is solved by nuclear magnetic resonance spectroscopy and small-angle X-ray scattering, and its complex with a region of the transcription factor DREB2A is provided through data-driven HADDOCK modeling and mutagenesis analysis. The RST fold is unique, but similar structures are identified in the PAH (paired amphipathic helix), TAFH (TATA-box-associated factor homology), and NCBD (nuclear coactivator binding domain) domains. We designate them as a group the αα hubs, as they share an αα-hairpin super-secondary motif, which serves as an organizing platform for malleable helices of varying topology. This allows for partner adaptation, exclusion, and selection. Our findings provide valuable insights into structural features enabling signaling fidelity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Unique structure of iC3b resolved at a resolution of 24 Å by 3D-electron microscopy.

PubMed

Alcorlo, Martin; Martínez-Barricarte, Ruben; Fernández, Francisco J; Rodríguez-Gallego, César; Round, Adam; Vega, M Cristina; Harris, Claire L; de Cordoba, Santiago Rodríguez; Llorca, Oscar

2011-08-09

Activation of C3, deposition of C3b on the target surface, and subsequent amplification by formation of a C3-cleaving enzyme (C3-convertase; C3bBb) triggers the effector functions of complement that result in inflammation and cell lysis. Concurrently, surface-bound C3b is proteolyzed to iC3b by factor I and appropriate cofactors. iC3b then interacts with the complement receptors (CR) of the Ig superfamily, CR2 (CD21), CR3 (CD11b/CD18), and CR4 (CD11c/CD18) on leukocytes, down-modulating inflammation, enhancing B cell-mediated immunity, and targeting pathogens for clearance by phagocytosis. Using EM and small-angle X-ray scattering, we now present a medium-resolution structure of iC3b (24 Å). iC3b displays a unique conformation with structural features distinct from any other C3 fragment. The macroglobulin ring in iC3b is similar to that in C3b, whereas the TED (thioester-containing domain) domain and the remnants of the CUB (complement protein subcomponents C1r/C1s, urchin embryonic growth factor and bone morphogenetic protein 1) domain have moved to locations more similar to where they were in native C3. A consequence of this large conformational change is the disruption of the factor B binding site, which renders iC3b unable to assemble a C3-convertase. This structural model also justifies the decreased interaction between iC3b and complement regulators and the recognition of iC3b by the CR of the Ig superfamily, CR2, CR3, and CR4. These data further illustrate the extraordinary conformational versatility of C3 to accommodate a great diversity of functional activities.

Adaptation and psychometric assessment of the Hebrew version of the Recovery Promoting Relationships Scale (RPRS).

PubMed

Moran, Galia S; Zisman-Ilani, Yaara; Garber-Epstein, Paula; Roe, David

2014-03-01

Recovery is supported by relationships that are characterized by human centeredness, empowerment and a hopeful approach. The Recovery Promoting Relationships Scale (RPRS; Russinova, Rogers, & Ellison, 2006) assesses consumer-provider relationships from the consumer perspective. Here we present the adaptation and psychometric assessment of a Hebrew version of the RPRS. The RPRS was translated to Hebrew (RPRS-Heb) using multiple strategies to assure conceptual soundness. Then 216 mental health consumers were administered the RPRS-Heb as part of a larger project initiative implementing illness management and recovery intervention (IMR) in community settings. Psychometric testing included assessment of the factor structure, reliability, and validity using the Hope Scale, the Working Alliance Inventory, and the Recovery Assessment Scale. The RPRS-Heb factor structure replicated the two factor structures found in the original scale with minor exceptions. Reliability estimates were good: Cronbach's alpha for the total scale was 0.94. An estimate of 0.93 for the Recovery-Promoting Strategies factor, and 0.86 for the Core Relationship. Concurrent validity was confirmed using the Working Alliance Scale (rp = .51, p < .001) and the Hope Scale (rp = .43, p < .001). Criterion validity was examined using the Recovery Assessment Scale (rp = .355, p < .05). The study yielded a 23-item RPRS-Heb version with a psychometrically sound factor structure, satisfactory reliability, and concurrent validity tested against the Hope, Alliance, and Recovery Assessment scales. Outcomes are discussed in the context of the original scale properties and a similar Dutch initiative. The RPRS-Heb can serve as a valuable tool for studying recovery promoting relationships with Hebrew speaking population.

Literature review on the structure and operation of Pharmacy and Therapeutics Committees.

PubMed

Durán-García, Esther; Santos-Ramos, Bernardo; Puigventos-Latorre, Francesc; Ortega, Ana

2011-06-01

To review the literature on the structure and operation of hospital Pharmacy and Therapeutics Committees from an international point of view and examine the factors that influence decision-making of these committees. We performed a literature search in the Medline and Embase databases from 1997 to January 2009 with the search terms: formulary system decision making, pharmacy and therapeutics committee, formularies hospital, drug formulary, survey, drug selection and outcome assessment health care. Inclusion criteria were the following: studies analyzing Pharmacy and Therapeutics Committees published in English or Spanish from 1997 to January 2009. Exclusion criteria were: publications which were editorials or opinion pieces, studies relating to one hospital, and studies where full text could not be attained. The analysis was divided into structural/organizational data and data on factors affecting the decision-making process. Seventeen studies met the inclusion criteria. Pharmacy and Therapeutics Committees and formularies were present in more than 90% of the hospitals in four of the five countries examined. Therapeutic interchange programs existed only in two of these countries. The mean number of committee members ranged between six and eight. More than 89% of the committees included a pharmacist. Standard operating procedures were implemented by 89% of the committees. The most influential factors in the decision-making were clinical trial results or drug costs rather than pharmacoeconomic studies. Other local organization-dependent factors were also important. The structure and operating procedures of Hospital Pharmacy and Therapeutics Committees are similar in select Western countries. Information from clinical trials is the most influential factor in the decision-making process.

Functional and structural insights into novel DREB1A transcription factors in common wheat (Triticum aestivum L.): A molecular modeling approach.

PubMed

Kumar, Anuj; Kumar, Sanjay; Kumar, Upendra; Suravajhala, Prashanth; Gajula, M N V Prasad

2016-10-01

Triticum aestivum L. known as common wheat is one of the most important cereal crops feeding a large and growing population. Various environmental stress factors including drought, high salinity and heat etc. adversely affect wheat production in a significant manner. Dehydration-responsive element-binding (DREB1A) factors, a class of transcription factors (TF) play an important role in combating drought stress. It is known that DREB1A specifically interacts with the dehydration responsive elements (DRE/CRT) inducing expression of genes involved in environmental stress tolerance in plants. Despite its critical interplay in plants, the structural and functional aspects of DREB1A TF in wheat remain unresolved. Previous studies showed that wheat DREBs (DREB1 and DREB2) were isolated using various methods including yeast two-hybrid screens but no extensive structural models were reported. In this study, we made an extensive in silico study to gain insight into DREB1A TF and reported the location of novel DREB1A in wheat chromosomes. We inferred the three-dimensional structural model of DREB1A using homology modelling and further evaluated them using molecular dynamics(MD) simulations yielding refined modelled structures. Our biochemical function predictions suggested that the wheat DREB1A orthologs have similar biochemical functions and pathways to that of AtDREB1A. In conclusion, the current study presents a structural perspective of wheat DREB1A and helps in understanding the molecular basis for the mechanism of DREB1A in response to environmental stress. Copyright © 2016 Elsevier Ltd. All rights reserved.

The psychometric properties of the generalized anxiety disorder-7 scale in Hispanic Americans with English or Spanish language preference.

PubMed

Mills, Sarah D; Fox, Rina S; Malcarne, Vanessa L; Roesch, Scott C; Champagne, Brian R; Sadler, Georgia Robins

2014-07-01

The Generalized Anxiety Disorder-7 scale (GAD-7) is a self-report questionnaire that is widely used to screen for anxiety. The GAD-7 has been translated into numerous languages, including Spanish. Previous studies evaluating the structural validity of the English and Spanish versions indicate a unidimensional factor structure in both languages. However, the psychometric properties of the Spanish language version have yet to be evaluated in samples outside of Spain, and the measure has not been tested for use among Hispanic Americans. This study evaluated the reliability, structural validity, and convergent validity of the English and Spanish language versions of the GAD-7 for Hispanic Americans in the United States. A community sample of 436 Hispanic Americans with an English (n = 210) or Spanish (n = 226) language preference completed the GAD-7. Multiple-group confirmatory factor analysis (CFA) was used to examine the goodness-of-fit of the unidimensional factor structure of the GAD-7 across language-preference groups. Results from the multiple-group CFA indicated a similar unidimensional factor structure with equivalent response patterns and item intercepts, but different variances, across language-preference groups. Internal consistency was good for both English and Spanish language-preference groups. The GAD-7 also evidenced good convergent validity as demonstrated by significant correlations in expected directions with the Perceived Stress Scale, the Patient Health Questionnaire-9, and the Physical Health domain of the World Health Organization Quality of Life-BREF assessment. The unidimensional GAD-7 is suitable for use among Hispanic Americans with an English or Spanish language preference.

Factor analysis of regional brain activation in bipolar and healthy individuals reveals a consistent modular structure.

PubMed

Fleck, David E; Welge, Jeffrey A; Eliassen, James C; Adler, Caleb M; DelBello, Melissa P; Strakowski, Stephen M

2018-07-01

The neurophysiological substrates of cognition and emotion, as seen with fMRI, are generally explained using modular structures. The present study was designed to probe the modular structure of cognitive-emotional processing in bipolar and healthy individuals using factor analysis and compare the results with current conceptions of the neurophysiology of bipolar disorder. Exploratory factor analysis was used to assess patterns of covariation among brain regions-of-interest activated during the Continuous Performance Task with Emotional and Neutral Distractors in healthy and bipolar individuals without a priori constraints on the number or composition of latent factors. Results indicated a common cognitive-emotional network consisting of prefrontal, medial temporal, limbic, parietal, anterior cingulate and posterior cingulate modules. However, reduced brain activation to emotional stimuli in the frontal, medial temporal and limbic modules was apparent in the bipolar relative to the healthy group, potentially accounting for emotional dysregulation in bipolar disorder. This study is limited by a relatively small sample size recruited at a single site. The results have yet to be validated on a larger independent sample. Although the modular structure of cognitive-emotional processing is similar in bipolar and healthy individuals, activation in response to emotional/neutral cues varies. These findings are not only consistent with recent conceptions of mood regulation in bipolar disorder, but also suggest that regional activation can be considered within tighter modular structures without compromising data interpretation. This demonstration may serve as a template for data reduction in future region-of-interest analyses to increase statistical power. Copyright © 2018 Elsevier B.V. All rights reserved.

Structural Determinants in Family Planning Service Utilization in Ethiopia: EDHS 2011 Analysis

PubMed Central

Gizachew Balew, Jembere; Cho, Yongtae; Tammy Kim, Clara; Ko, Woorim

2015-01-01

Family planning coverage has improved in Ethiopia in the last decade, though fertility is still about 5.8 in the rural setup. In this paper, the major structural determinants of family planning service were analyzed using a multilevel model from 8906 individual women observation in the 2011 EDHS data. The results show that there is a big variation in family planning use both at the individual and between group levels. More than 39% of the variation in FP use is explained by contextual cluster level differences. Most of the socioeconomic predictors; respondent's education, ethnicity, and partners' education as well as employment status and urbanization were found to be significant factors that affect FP use. Similarly health extension visit and media access were found to be strong factors that affect FP service at both individual and cluster levels. This evidence concludes that addressing these contextual factors is very crucial to strengthen FP use and fertility reduction in the nation, beyond individual behavioral changes. PMID:26783520

Cultural-based biases of the GAD-7.

PubMed

Parkerson, Holly A; Thibodeau, Michel A; Brandt, Charles P; Zvolensky, Michael J; Asmundson, Gordon J G

2015-04-01

The GAD-7 is a popular measure of generalized anxiety disorder (GAD) symptoms that has been used across many cultural groups. Existing evidence demonstrates that the prevalence of GAD varies across self-identified ethnic/cultural groups, a phenomenon that some researchers attribute to cross-cultural measurement error rather than to actual differences in rates of GAD. Nonetheless, the effect of culture on factor structure and response patterns to the GAD-7 have not been examined and could result over- or under-estimated GAD-7 scores across different cultural groups. The current investigation assessed the factor structure of the GAD-7 in White/Caucasian, Hispanic, and Black/African American undergraduates and tested for cultural-based biases. A modified one-factor model exhibited good fit across subsamples. Results revealed that Black/African American participants with high GAD symptoms scored lower on the GAD-7 than other participants with similar GAD symptoms. Results highlight the need for culturally sensitive GAD screening tools. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling drivers of phosphorus loads in Chesapeake Bay tributaries and inferences about long-term change

USGS Publications Warehouse

Ryberg, Karen R.; Blomquist, Joel; Sprague, Lori A.; Sekellick, Andrew J.; Keisman, Jennifer

2018-01-01

Causal attribution of changes in water quality often consists of correlation, qualitative reasoning, listing references to the work of others, or speculation. To better support statements of attribution for water-quality trends, structural equation modeling was used to model the causal factors of total phosphorus loads in the Chesapeake Bay watershed. By transforming, scaling, and standardizing variables, grouping similar sites, grouping some causal factors into latent variable models, and using methods that correct for assumption violations, we developed a structural equation model to show how causal factors interact to produce total phosphorus loads. Climate (in the form of annual total precipitation and the Palmer Hydrologic Drought Index) and anthropogenic inputs are the major drivers of total phosphorus load in the Chesapeake Bay watershed. Increasing runoff due to natural climate variability is offsetting purposeful management actions that are otherwise decreasing phosphorus loading; consequently, management actions may need to be reexamined to achieve target reductions in the face of climate variability.

The Cyber Aggression in Relationships Scale: A New Multidimensional Measure of Technology-Based Intimate Partner Aggression.

PubMed

Watkins, Laura E; Maldonado, Rosalita C; DiLillo, David

2018-07-01

The purpose of this study was to develop and provide initial validation for a measure of adult cyber intimate partner aggression (IPA): the Cyber Aggression in Relationships Scale (CARS). Drawing on recent conceptual models of cyber IPA, items from previous research exploring general cyber aggression and cyber IPA were modified and new items were generated for inclusion in the CARS. Two samples of adults 18 years or older were recruited online. We used item factor analysis to test the factor structure, model fit, and invariance of the measure structure across women and men. Results confirmed that three-factor models for both perpetration and victimization demonstrated good model fit, and that, in general, the CARS measures partner cyber aggression similarly for women and men. The CARS also demonstrated validity through significant associations with in-person IPA, trait anger, and jealousy. Findings suggest the CARS is a useful tool for assessing cyber IPA in both research and clinical settings.

Integrating Prospective Longitudinal Data: Modeling Personality and Health in the Terman Life Cycle and Hawaii Longitudinal Studies

PubMed Central

Kern, Margaret L.; Hampson, Sarah E.; Goldberg, Lewis R.; Friedman, Howard S.

2013-01-01

The present study used a collaborative framework to integrate two long-term prospective studies: the Terman Life Cycle Study and the Hawaii Personality and Health Longitudinal Study. Using a five-factor personality-trait framework, teacher assessments of child personality were rationally and empirically aligned to establish similar factor structures across samples. Comparable items related to adult self-rated health, education, and alcohol use were harmonized, and data were pooled on harmonized items. A structural model was estimated, allowing paths to differ by sample. Harmonized child personality factors were then used to examine markers of physiological dysfunction in the Hawaii sample and mortality risk in the Terman sample. Harmonized conscientiousness predicted less physiological dysfunction in the Hawaii sample and lower mortality risk in the Terman sample. These results illustrate how collaborative, integrative work with multiple samples offers the exciting possibility that samples from different cohorts and ages can be linked together to directly test lifespan theories of personality and health. PMID:23231689

Cytokines and pulmonary fibrosis.

PubMed Central

Gauldie, J.; Jordana, M.; Cox, G.

1993-01-01

Chronically inflamed and fibrotic tissue of the respiratory tract can be shown to actively express the genes and products of a number of powerful growth and differentiating factors. The initial activation of lung inflammatory cells, including alveolar macrophages, is presumed to result in the release of early acting cytokines such as IL-1 and TNF. Subsequent activation and possible phenotype alteration of the structural cells results in release of other growth factors and accumulation of blood derived inflammatory cells. These cells, once they have entered the tissue and become further activated, may begin to release their own autocrine factors and "feed back" some of the similar signals to the tissue cells in a paracrine manner, further inducing differentiation and phenotype change. These internal tissue cell and cytokine cascades could account for the chronic nature of the inflammation. Therapeutic intervention must therefore take into account the inflammatory component as well as the nature of the cytokines and structural cells involved in the propagation of the disease. PMID:8236078

Exploration of peptides that fit into the thermally vibrating active site of cathepsin K protease by alternating artificial intelligence and molecular simulation

NASA Astrophysics Data System (ADS)

Nishiyama, Katsuhiko

2017-08-01

Eighteen tripeptides that fit into the thermally vibrating active site of cathepsin K were discovered by alternating artificial intelligence and molecular simulation. The 18 tripeptides fit the active site better than the cysteine protease inhibitor E64, and a better inhibitor of cathepsin K could be designed considering these tripeptides. Among the 18 tripeptides, Phe-Arg-Asp and Tyr-Arg-Asp fit the active site the best and their structural similarity should be considered in the design process. Interesting factors emerged from the structure of the decision tree, and its structural information will guide exploration of potential inhibitor molecules for proteases.

Thiophene-Based Organic Semiconductors.

PubMed

Turkoglu, Gulsen; Cinar, M Emin; Ozturk, Turan

2017-10-24

Thiophene-based π-conjugated organic small molecules and polymers are the research subject of significant current interest owing to their potential use as organic semiconductors in material chemistry. Despite simple and similar molecular structures, the hitherto reported properties of thiophene-based organic semiconductors are rather diverse. Design of high performance organic semiconducting materials requires a thorough understanding of inter- and intra-molecular interactions, solid-state packing, and the influence of both factors on the charge carrier transport. In this chapter, thiophene-based organic semiconductors, which are classified in terms of their chemical structures and their structure-property relationships, are addressed for the potential applications as organic photovoltaics (OPVs), organic field-effect transistors (OFETs) and organic light emitting diodes (OLEDs).

Stress Analysis of Columns and Beam Columns by the Photoelastic Method

NASA Technical Reports Server (NTRS)

Ruffner, B F

1946-01-01

Principles of similarity and other factors in the design of models for photoelastic testing are discussed. Some approximate theoretical equations, useful in the analysis of results obtained from photoelastic tests are derived. Examples of the use of photoelastic techniques and the analysis of results as applied to uniform and tapered beam columns, circular rings, and statically indeterminate frames, are given. It is concluded that this method is an effective tool for the analysis of structures in which column action is present, particularly in tapered beam columns, and in statically indeterminate structures in which the distribution of loads in the structures is influenced by bending moments due to axial loads in one or more members.

Evaluation of the Compulsive Exercise Test (CET) in Adolescents with Eating Disorders: Factor Structure and Relation to Eating Disordered Psychopathology.

PubMed

Swenne, Ingemar

2016-07-01

The aims of this study were to explore the factor structure of the Compulsive Exercise Test (CET) in a clinical sample of Swedish adolescents with eating disorders (ED) and to study the relationship of CET with ED cognitions, body weight and exercise frequency. The compulsive Exercise Test, the Eating Disorders Examination-Questionnaire, body mass index (BMI) and exercise frequency were available at assessment of 210 adolescents (age 14.4 ± 1.6 years) with ED. Factor analysis generated four factors with close similarity to factors previously obtained in a community sample of adolescents samples and supported the use of the original version of CET. Exercise for weight control was strongly related to ED cognitions but less to exercise frequency and BMI. Exercise for regulation of mood was related to ED cognitions and exercise frequency but not to BMI. In adolescents with ED, different aspects of exercise are related to ED cognitions. This needs addressing in the treatment of adolescents with ED. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association.

Tenofovir Nephrotoxicity: 2011 Update

PubMed Central

Fernandez-Fernandez, Beatriz; Montoya-Ferrer, Ana; Sanz, Ana B.; Sanchez-Niño, Maria D.; Izquierdo, Maria C.; Poveda, Jonay; Sainz-Prestel, Valeria; Ortiz-Martin, Natalia; Parra-Rodriguez, Alejandro; Selgas, Rafael; Ruiz-Ortega, Marta; Egido, Jesus; Ortiz, Alberto

2011-01-01

Tenofovir is an acyclic nucleotide analogue reverse-transcriptase inhibitor structurally similar to the nephrotoxic drugs adefovir and cidofovir. Tenofovir is widely used to treat HIV infection and approved for treatment of hepatitis B virus. Despite initial cell culture and clinical trials results supporting the renal safety of tenofovir, its clinical use is associated with a low, albeit significant, risk of kidney injury. Proximal tubular cell secretion of tenofovir explains the accumulation of the drug in these mitochondria-rich cells. Tenofovir nephrotoxicity is characterized by proximal tubular cell dysfunction that may be associated with acute kidney injury or chronic kidney disease. Withdrawal of the drug leads to improvement of analytical parameters that may be partial. Understanding the risk factors for nephrotoxicity and regular monitoring of proximal tubular dysfunction and serum creatinine in high-risk patients is required to minimize nephrotoxicity. Newer, structurally similar molecular derivatives that do not accumulate in proximal tubules are under study. PMID:21716719

Latent constructs of the autobiographical memory questionnaire: a recollection-belief model of autobiographical experience.

PubMed

Fitzgerald, Joseph M; Broadbridge, Carissa L

2013-01-01

Many researchers employ single-item scales of subjective experiences such as imagery and confidence to assess autobiographical memory. We tested the hypothesis that four latent constructs, recollection, belief, impact, and rehearsal, account for the variance in commonly used scales across four different types of autobiographical memory: earliest childhood memory, cue word memory of personal experience, highly vivid memory, and most stressful memory. Participants rated each memory on scales hypothesised to be indicators of one of four latent constructs. Multi-group confirmatory factor analyses and structural analyses confirmed the similarity of the latent constructs of recollection, belief, impact, and rehearsal, as well as the similarity of the structural relationships among those constructs across memory type. The observed pattern of mean differences between the varieties of autobiographical experiences was consistent with prior research and theory in the study of autobiographical memory.

Approving for a community aged care package: experiences and perceptions of six metropolitan aged care assessment service teams.

PubMed

Stephens, Delwyne; Wells, Yvonne; Gardner, Ian

2011-06-01

To establish whether the experiences and perceptions of different metropolitan Aged Care Assessment Service (ACAS) teams when approving people for Community Aged Care Packages (CACPs) were similar. Six semi-structured 30-minute group interviews were completed. ACAS team approval processes for CACPs were similar. The primary criterion for approval was need for case management. Many factors, however, impinged on the approval process. Barriers to making approvals included long waiting times, a lack of confidence in the priority rating system, and consideration of whether a person was better off with Home and Community Care services because of the impact of the Australian Government's Cost Recovery policy. ACAS teams have competing considerations when approving a person for a CACP. In particular, structural barriers, such as cost recovery policies, can have a significant negative impact on approval decisions. © 2010 The Authors. Journal compilation © 2010 ACOTA.

A size-structured model of bacterial growth and reproduction.

PubMed

Ellermeyer, S F; Pilyugin, S S

2012-01-01

We consider a size-structured bacterial population model in which the rate of cell growth is both size- and time-dependent and the average per capita reproduction rate is specified as a model parameter. It is shown that the model admits classical solutions. The population-level and distribution-level behaviours of these solutions are then determined in terms of the model parameters. The distribution-level behaviour is found to be different from that found in similar models of bacterial population dynamics. Rather than convergence to a stable size distribution, we find that size distributions repeat in cycles. This phenomenon is observed in similar models only under special assumptions on the functional form of the size-dependent growth rate factor. Our main results are illustrated with examples, and we also provide an introductory study of the bacterial growth in a chemostat within the framework of our model.

The hierarchical structure of childhood personality in five countries: continuity from early childhood to early adolescence.

PubMed

Tackett, Jennifer L; Slobodskaya, Helena R; Mar, Raymond A; Deal, James; Halverson, Charles F; Baker, Spencer R; Pavlopoulos, Vassilis; Besevegis, Elias

2012-08-01

Childhood personality is a rapidly growing area of investigation within individual differences research. One understudied topic is the universality of the hierarchical structure of childhood personality. In the present investigation, parents rated the personality characteristics of 3,751 children from 5 countries and 4 age groups. The hierarchical structure of childhood personality was examined for 1-, 2-, 3-, 4-, and 5-factor models across country (Canada, China, Greece, Russia, and the United States) and age group (3-5, 6-8, 9-11, and 12-14 years of age). Many similarities were noted across both country and age. The Five-Factor Model was salient beginning in early childhood (ages 3-5). Deviations across groups and from adult findings are noted, including the prominent role of antagonism in childhood personality and the high covariation between Conscientiousness and intellect. Future directions, including the need for more explicit attempts to merge temperament and personality models, are discussed. © 2011 The Authors. Journal of Personality © 2011, Wiley Periodicals, Inc.

Low-Dimensional Network Formation in Molten Sodium Carbonate

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

Wilding, Martin C.; Wilson, Mark; Alderman, Oliver L. G.

2016-04-15

Molten carbonates are highly inviscid liquids characterized by low melting points and high solubility of rare earth elements and volatile molecules. An understanding of the structure and related properties of these intriguing liquids has been limited to date. We report the results of a study of molten sodium carbonate (Na2CO3) which combines high energy X-ray diffraction, containerless techniques and computer simulation to provide insight into the liquid structure. Total structure factors (F-x(Q)) are collected on the laser-heated carbonate spheres suspended in flowing gases of varying composition in an aerodynamic levitation furnace. The respective partial structure factor contributions to Fx(Q) aremore » obtained by performing molecular dynamics simulations treating the carbonate anions as flexible entities. The carbonate liquid structure is found to be heavily temperature-dependent. At low temperatures a low-dimensional carbonate chain network forms, at T = 1100 K for example similar to 55% of the C atoms form part of a chain. The mean chain lengths decrease as temperature is increased and as the chains become shorter the rotation of the carbonate anions becomes more rapid enhancing the diffusion of Na+ ions.« less

Calcium-independent metal-ion catalytic mechanism of anthrax edema factor

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

Shen, Yuequan; Zhukovskaya, Natalia L.; Guo, Qing

2009-11-18

Edema factor (EF), a key anthrax exotoxin, has an anthrax protective antigen-binding domain (PABD) and a calmodulin (CaM)-activated adenylyl cyclase domain. Here, we report the crystal structures of CaM-bound EF, revealing the architecture of EF PABD. CaM has N- and C-terminal domains and each domain can bind two calcium ions. Calcium binding induces the conformational change of CaM from closed to open. Structures of the EF-CaM complex show how EF locks the N-terminal domain of CaM into a closed conformation regardless of its calcium-loading state. This represents a mechanism of how CaM effector alters the calcium affinity of CaM andmore » uncouples the conformational change of CaM from calcium loading. Furthermore, structures of EF-CaM complexed with nucleotides show that EF uses two-metal-ion catalysis, a prevalent mechanism in DNA and RNA polymerases. A histidine (H351) further facilitates the catalysis of EF by activating a water to deprotonate 3'OH of ATP. Mammalian adenylyl cyclases share no structural similarity with EF and they also use two-metal-ion catalysis, suggesting the catalytic mechanism-driven convergent evolution of two structurally diverse adenylyl cyclases.« less

Evaluation of the late life disability instrument in the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) study.

PubMed

Hsu, Fang-Chi; Rejeski, W Jack; Ip, Edward H; Katula, Jeff A; Fielding, Roger; Jette, Alan M; Studenski, Stephanie A; Blair, Steven N; Miller, Michael E

2010-10-06

The late life disability instrument (LLDI) was developed to assess limitations in instrumental and management roles using a small and restricted sample. In this paper we examine the measurement properties of the LLDI using data from the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) study. LIFE-P participants, aged 70-89 years, were at elevated risk of disability. The 424 participants were enrolled at the Cooper Institute, Stanford University, University of Pittsburgh, and Wake Forest University. Physical activity and successful aging health education interventions were compared after 12-months of follow-up. Using factor analysis, we determined whether the LLDI's factor structure was comparable with that reported previously. We further examined how each item related to measured disability using item response theory (IRT). The factor structure for the limitation domain within the LLDI in the LIFE-P study did not corroborate previous findings. However, the factor structure using the abbreviated version was supported. Social and personal role factors were identified. IRT analysis revealed that each item in the social role factor provided a similar level of information, whereas the items in the personal role factor tended to provide different levels of information. Within the context of community-based clinical intervention research in aged populations, an abbreviated version of the LLDI performed better than the full 16-item version. In addition, the personal subscale would benefit from additional research using IRT. The protocol of LIFE-P is consistent with the principles of the Declaration of Helsinki and is registered at http://www.ClinicalTrials.gov (registration # NCT00116194).

Perfectionism among Chinese Gifted and Nongifted Students in Hong Kong: The Use of the Revised Almost Perfect Scale

ERIC Educational Resources Information Center

Chan, David W.

2011-01-01

This study investigated the structure of perfectionism based on the almost Perfect Scale-Revised with a sample of 320 gifted students aged 7 to 12 and a sample of 882 nongifted students of similar ages in Hong Kong. Multigroup confirmatory factor analyses across the two student groups supported a common three-dimensional model that included…

Structure of the Newcastle disease virus F protein in the post-fusion conformation

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

Swanson, Kurt; Wen, Xiaolin; Leser, George P.

2010-11-17

The paramyxovirus F protein is a class I viral membrane fusion protein which undergoes a significant refolding transition during virus entry. Previous studies of the Newcastle disease virus, human parainfluenza virus 3 and parainfluenza virus 5 F proteins revealed differences in the pre- and post-fusion structures. The NDV Queensland (Q) F structure lacked structural elements observed in the other two structures, which are key to the refolding and fusogenic activity of F. Here we present the NDV Australia-Victoria (AV) F protein post-fusion structure and provide EM evidence for its folding to a pre-fusion form. The NDV AV F structure containsmore » heptad repeat elements missing in the previous NDV Q F structure, forming a post-fusion six-helix bundle (6HB) similar to the post-fusion hPIV3 F structure. Electrostatic and temperature factor analysis of the F structures points to regions of these proteins that may be functionally important in their membrane fusion activity.« less

Global search in photoelectron diffraction structure determination using genetic algorithms

NASA Astrophysics Data System (ADS)

Viana, M. L.; Díez Muiño, R.; Soares, E. A.; Van Hove, M. A.; de Carvalho, V. E.

2007-11-01

Photoelectron diffraction (PED) is an experimental technique widely used to perform structural determinations of solid surfaces. Similarly to low-energy electron diffraction (LEED), structural determination by PED requires a fitting procedure between the experimental intensities and theoretical results obtained through simulations. Multiple scattering has been shown to be an effective approach for making such simulations. The quality of the fit can be quantified through the so-called R-factor. Therefore, the fitting procedure is, indeed, an R-factor minimization problem. However, the topography of the R-factor as a function of the structural and non-structural surface parameters to be determined is complex, and the task of finding the global minimum becomes tough, particularly for complex structures in which many parameters have to be adjusted. In this work we investigate the applicability of the genetic algorithm (GA) global optimization method to this problem. The GA is based on the evolution of species, and makes use of concepts such as crossover, elitism and mutation to perform the search. We show results of its application in the structural determination of three different systems: the Cu(111) surface through the use of energy-scanned experimental curves; the Ag(110)-c(2 × 2)-Sb system, in which a theory-theory fit was performed; and the Ag(111) surface for which angle-scanned experimental curves were used. We conclude that the GA is a highly efficient method to search for global minima in the optimization of the parameters that best fit the experimental photoelectron diffraction intensities to the theoretical ones.

Hypochondriasis Y-BOCS: a study of the psychometric properties of a clinician-administered semi-structured interview to assess hypochondriacal thoughts and behaviours.

PubMed

Greeven, Anja; Spinhoven, Philip; van Balkom, Anton J L M

2009-01-01

This study investigated the psychometric properties of the first clinician-administered semi-structured interview for assessing the severity of hypochondriacal symptoms. The Hypochondriasis Yale-Brown Obsessive-Compulsive Scale (H-YBOCS) consisted of three a priori dimensions: hypochondriacal obsessions, compulsions and avoidance. The 16-item interview was conducted with 112 participants with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, hypochondriasis. We analysed factor analytic structure, reliability, construct validity and sensitivity to change. Factor analysis supported a three-factor model similar to the a priori dimensions. Internal consistency ranged from satisfactory to good. Inter-rater reliability was excellent. The construct validity was low to moderate. The H-YBOCS was sensitive for measuring changes in symptom severity. The H-YBOCS is a (factorially) valid and coherent interview with a high level of agreement across different raters. The relatively low discriminant validity could be due to co-morbid anxiety and depressive disorders. Overall, the H-YBOCS seems to be a promising contribution to the assessment of hypochondriasis. *The hypochondriasis Y-BOCS is a feasible clinician rated interview to assess the severity of hypochondriacal complaints.

Urban American Indian Adolescent Girls: Framing Sexual Risk Behavior

PubMed Central

Martyn, Kristy K.; Momper, Sandra L.; Loveland-Cherry, Carol J.; Low, Lisa Kane

2014-01-01

Purpose American Indian (AI) adolescent girls have higher rates of sexual activity, births and STIs compared to the national average. The purpose of this study was to explore factors that influence urban adolescent AI girls' sexual risk behavior (SRB). Design A qualitative study was conducted using grounded theory methodology to reveal factors and processes that influence SRB. Methods Talking circles, individual interviews, and event history calendars were used with 20 urban AI 15-19 year old girls to explore influences on their sexual behavior. Findings The generated theory, Framing Sexual Risk Behavior, describes both social and structural factors and processes that influenced the girls' sexual behaviors. The theory extends Bronfenbrenner's ecological model by identifying microsystem, mesosystem, and macrosystem influences on sexual behavior, including: Microsystem: Being “Normal,” Native, and Having Goals; Mesosystem: Networks of Family and Friends, Environmental Influences, and Sex Education; and Macrosystem: Tribal Traditions/History and Federal Policy. Discussion Urban AI girls reported similar social and structural influences on SRB as urban adolescents from other racial and ethnic groups. However, differences were noted in the family structure, cultural heritage, and unique history of AIs. Implications for Practice This theory can be used in culturally responsive practice with urban AI girls. PMID:24803532

Similarity measure and domain adaptation in multiple mixture model clustering: An application to image processing.

PubMed

Leong, Siow Hoo; Ong, Seng Huat

2017-01-01

This paper considers three crucial issues in processing scaled down image, the representation of partial image, similarity measure and domain adaptation. Two Gaussian mixture model based algorithms are proposed to effectively preserve image details and avoids image degradation. Multiple partial images are clustered separately through Gaussian mixture model clustering with a scan and select procedure to enhance the inclusion of small image details. The local image features, represented by maximum likelihood estimates of the mixture components, are classified by using the modified Bayes factor (MBF) as a similarity measure. The detection of novel local features from MBF will suggest domain adaptation, which is changing the number of components of the Gaussian mixture model. The performance of the proposed algorithms are evaluated with simulated data and real images and it is shown to perform much better than existing Gaussian mixture model based algorithms in reproducing images with higher structural similarity index.

Similarity measure and domain adaptation in multiple mixture model clustering: An application to image processing

PubMed Central

Leong, Siow Hoo

2017-01-01

This paper considers three crucial issues in processing scaled down image, the representation of partial image, similarity measure and domain adaptation. Two Gaussian mixture model based algorithms are proposed to effectively preserve image details and avoids image degradation. Multiple partial images are clustered separately through Gaussian mixture model clustering with a scan and select procedure to enhance the inclusion of small image details. The local image features, represented by maximum likelihood estimates of the mixture components, are classified by using the modified Bayes factor (MBF) as a similarity measure. The detection of novel local features from MBF will suggest domain adaptation, which is changing the number of components of the Gaussian mixture model. The performance of the proposed algorithms are evaluated with simulated data and real images and it is shown to perform much better than existing Gaussian mixture model based algorithms in reproducing images with higher structural similarity index. PMID:28686634

Comparison of experimental and calculated chiroptical spectra for chiral molecular structure determination.

PubMed

Polavarapu, Prasad L; Covington, Cody L

2014-09-01

For three different chiroptical spectroscopic methods, namely, vibrational circular dichroism (VCD), electronic circular dichroism (ECD), and Raman optical activity (ROA), the measures of similarity of the experimental spectra to the corresponding spectra predicted using quantum chemical theories are summarized. In determining the absolute configuration and/or predominant conformations of chiral molecules, these similarity measures provide numerical estimates of agreement between experimental observations and theoretical predictions. Selected applications illustrating the similarity measures for absorption, circular dichroism, and corresponding dissymmetry factor (DF) spectra, in the case of VCD and ECD, and for Raman, ROA, and circular intensity differential (CID) spectra in the case of ROA, are presented. The analysis of similarity in DF or CID spectra is considered to be much more discerning and accurate than that in absorption (or Raman) and circular dichroism (or ROA) spectra, undertaken individually. © 2014 Wiley Periodicals, Inc.

How are population-based funding formulae for healthcare composed? A comparative analysis of seven models.

PubMed

Penno, Erin; Gauld, Robin; Audas, Rick

2013-11-08

Population-based funding formulae act as an important means of promoting equitable health funding structures. To evaluate how policy makers in different jurisdictions construct health funding formulae and build an understanding of contextual influences underpinning formula construction we carried out a comparative analysis of key components of funding formulae across seven high-income and predominantly publically financed health systems: New Zealand, England, Scotland, the Netherlands, the state of New South Wales in Australia, the Canadian province of Ontario, and the city of Stockholm, Sweden. Core components from each formula were summarised and key similarities and differences evaluated from a compositional perspective. We categorised approaches to constructing funding formulae under three main themes: identifying factors which predict differential need amongst populations; adjusting for cost factors outside of needs factors; and engaging in normative correction of allocations for 'unmet' need. We found significant congruence in the factors used to guide need and cost adjustments. However, there is considerable variation in interpretation and implementation of these factors. Despite broadly similar frameworks, there are distinct differences in the composition of the formulae across the seven health systems. Ultimately, the development of funding formulae is a dynamic process, subject to availability of data reflecting health needs, the influence of wider socio-political objectives and health system determinants.

Comparison of modal identification techniques using a hybrid-data approach

NASA Technical Reports Server (NTRS)

Pappa, Richard S.

1986-01-01

Modal identification of seemingly simple structures, such as the generic truss is often surprisingly difficult in practice due to high modal density, nonlinearities, and other nonideal factors. Under these circumstances, different data analysis techniques can generate substantially different results. The initial application of a new hybrid-data method for studying the performance characteristics of various identification techniques with such data is summarized. This approach offers new pieces of information for the system identification researcher. First, it allows actual experimental data to be used in the studies, while maintaining the traditional advantage of using simulated data. That is, the identification technique under study is forced to cope with the complexities of real data, yet the performance can be measured unquestionably for the artificial modes because their true parameters are known. Secondly, the accuracy achieved for the true structural modes in the data can be estimated from the accuracy achieved for the artificial modes if the results show similar characteristics. This similarity occurred in the study, for example, for a weak structural mode near 56 Hz. It may even be possible--eventually--to use the error information from the artificial modes to improve the identification accuracy for the structural modes.

Gain and refractive index dynamics in p-doped InAs quantum dash semiconductor optical amplifiers

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

Komolibus, Katarzyna; Tyndall National Institute, University College Cork, Cork T12 R5CP; Piwonski, Tomasz, E-mail: tomasz.piwonski@tyndall.ie

The ultrafast carrier dynamics in a p-doped dash-in-a-well structure at 1.5 μm is experimentally investigated. An analysis of the timescales related to carrier relaxation and escape processes as well as the “dynamical” linewidth enhancement factor is presented and compared with results obtained from similar un-doped materials. Intentional p-doping of the active region results in an enhancement of the intermediate timescale of the gain dynamics associated with phonon-assisted electron capture and a reduction of the α-factor due to increased differential gain.

Structural and Functional Studies Indicate That the EPEC Effector, EspG, Directly Binds p21-Activated Kinase

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

Germane, Katherine L.; Spiller, Benjamin W.

2011-09-20

Bacterial pathogens secrete effectors into their hosts that subvert host defenses and redirect host processes. EspG is a type three secretion effector with a disputed function that is found in enteropathogenic Escherichia coli. Here we show that EspG is structurally similar to VirA, a Shigella virulence factor; EspG has a large, conserved pocket on its surface; EspG binds directly to the amino-terminal inhibitory domain of human p21-activated kinase (PAK); and mutations to conserved residues in the surface pocket disrupt the interaction with PAK.

The Role of Structural Barriers in Risky Sexual Behavior, Victimization and Readiness to Change HIV/STI-Related Risk Behavior Among Transgender Women.

PubMed

Raiford, Jerris L; Hall, Grace J; Taylor, Raekiela D; Bimbi, David S; Parsons, Jeffrey T

2016-10-01

This study examines the role of structural barriers experienced by a community-based sample of 63 HIV-positive and negative transgender women that may elevate HIV infection and transmission risks. Separate hierarchical linear multiple regression analyses tested the association between structural barriers (e.g., unemployment, lack of food, shelter) and condomless anal sex acts, abuse, and readiness to change risk behavior, while controlling for other related factors. Among this primarily Hispanic and African-American sample, HIV-positive and negative transgender women experienced a similar number of structural barriers and experiencing structural barriers was significantly associated with an increased number of condomless anal sex acts (p = .002), victimization (p = .000) and a decreased readiness to change HIV-related risk behavior (p = .014). Structural-level interventions are needed to address this elevated risk among this underserved and hard-to-reach population.

The Greenland shark Somniosus microcephalus-Hemoglobins and ligand-binding properties.

PubMed

Russo, Roberta; Giordano, Daniela; Paredi, Gianluca; Marchesani, Francesco; Milazzo, Lisa; Altomonte, Giovanna; Del Canale, Pietro; Abbruzzetti, Stefania; Ascenzi, Paolo; di Prisco, Guido; Viappiani, Cristiano; Fago, Angela; Bruno, Stefano; Smulevich, Giulietta; Verde, Cinzia

2017-01-01

A large amount of data is currently available on the adaptive mechanisms of polar bony fish hemoglobins, but structural information on those of cartilaginous species is scarce. This study presents the first characterisation of the hemoglobin system of one of the longest-living vertebrate species (392 ± 120 years), the Arctic shark Somniosus microcephalus. Three major hemoglobins are found in its red blood cells and are made of two copies of the same α globin combined with two copies of three very similar β subunits. The three hemoglobins show very similar oxygenation and carbonylation properties, which are unaffected by urea, a very important compound in marine elasmobranch physiology. They display identical electronic absorption and resonance Raman spectra, indicating that their heme-pocket structures are identical or highly similar. The quaternary transition equilibrium between the relaxed (R) and the tense (T) states is more dependent on physiological allosteric effectors than in human hemoglobin, as also demonstrated in polar teleost hemoglobins. Similar to other cartilaginous fishes, we found no evidence for functional differentiation among the three isoforms. The very similar ligand-binding properties suggest that regulatory control of O2 transport may be at the cellular level and that it may involve changes in the cellular concentrations of allosteric effectors and/or variations of other systemic factors. The hemoglobins of this polar shark have evolved adaptive decreases in O2 affinity in comparison to temperate sharks.

The Greenland shark Somniosus microcephalus—Hemoglobins and ligand-binding properties

PubMed Central

Paredi, Gianluca; Marchesani, Francesco; Milazzo, Lisa; Altomonte, Giovanna; Del Canale, Pietro; Abbruzzetti, Stefania; Ascenzi, Paolo; di Prisco, Guido; Viappiani, Cristiano; Fago, Angela; Bruno, Stefano; Smulevich, Giulietta

2017-01-01

A large amount of data is currently available on the adaptive mechanisms of polar bony fish hemoglobins, but structural information on those of cartilaginous species is scarce. This study presents the first characterisation of the hemoglobin system of one of the longest-living vertebrate species (392 ± 120 years), the Arctic shark Somniosus microcephalus. Three major hemoglobins are found in its red blood cells and are made of two copies of the same α globin combined with two copies of three very similar β subunits. The three hemoglobins show very similar oxygenation and carbonylation properties, which are unaffected by urea, a very important compound in marine elasmobranch physiology. They display identical electronic absorption and resonance Raman spectra, indicating that their heme-pocket structures are identical or highly similar. The quaternary transition equilibrium between the relaxed (R) and the tense (T) states is more dependent on physiological allosteric effectors than in human hemoglobin, as also demonstrated in polar teleost hemoglobins. Similar to other cartilaginous fishes, we found no evidence for functional differentiation among the three isoforms. The very similar ligand-binding properties suggest that regulatory control of O2 transport may be at the cellular level and that it may involve changes in the cellular concentrations of allosteric effectors and/or variations of other systemic factors. The hemoglobins of this polar shark have evolved adaptive decreases in O2 affinity in comparison to temperate sharks. PMID:29023598

The three-dimensional structure of the native ternary complex of bovine pancreatic procarboxypeptidase A with proproteinase E and chymotrypsinogen C.

PubMed Central

Gomis-Rüth, F X; Gómez, M; Bode, W; Huber, R; Avilés, F X

1995-01-01

The metalloexozymogen procarboxypeptidase A is mainly secreted in ruminants as a ternary complex with zymogens of two serine endoproteinases, chymotrypsinogen C and proproteinase E. The bovine complex has been crystallized, and its molecular structure analysed and refined at 2.6 A resolution to an R factor of 0.198. In this heterotrimer, the activation segment of procarboxypeptidase A essentially clamps the other two subunits, which shield the activation sites of the former from tryptic attack. In contrast, the propeptides of both serine proproteinases are freely accessible to trypsin. This arrangement explains the sequential and delayed activation of the constituent zymogens. Procarboxypeptidase A is virtually identical to the homologous monomeric porcine form. Chymotrypsinogen C displays structural features characteristic for chymotrypsins as well as elastases, except for its activation domain; similar to bovine chymotrypsinogen A, its binding site is not properly formed, while its surface located activation segment is disordered. The proproteinase E structure is fully ordered and strikingly similar to active porcine elastase; its specificity pocket is occluded, while the activation segment is fixed to the molecular surface. This first structure of a native zymogen from the proteinase E/elastase family does not fundamentally differ from the serine proproteinases known so far. Images PMID:7556081

Factor structure of the functional movement screen in marine officer candidates.

PubMed

Kazman, Josh B; Galecki, Jeffrey M; Lisman, Peter; Deuster, Patricia A; OʼConnor, Francis G

2014-03-01

Functional movement screening (FMS) is a musculoskeletal assessment that is intended to fill a gap between preparticipation examinations and performance tests. Functional movement screening consists of 7 standardized movements involving multiple muscle groups that are rated 0-3 during performance; scores are combined into a final score, which is intended to predict injury risk. This use of a sum-score in this manner assumes that the items are unidimensional and scores are internally consistent, which are measures of internal reliability. Despite research into the FMS' predictive value and interrater reliability, research has not assessed its psychometric properties. The present study is a standard psychometric analysis of the FMS and is the first to assess the internal consistency and factor structure of the FMS, using Cronbach's alpha and exploratory factor analysis (EFA). Using a cohort of 877 male and 57 female Marine officer candidates who performed the FMS, EFA of polychoric correlations with varimax rotation was conducted to explore the structure of the FMS. Tests were repeated on the original scores, which integrated feelings of pain during movement (0-3), and then on scores discounting the pain instruction and based only on the performance (1-3), to determine whether pain ratings affected the factor structure. The average FMS score was 16.7 ± 1.8. Cronbach's alpha was 0.39. Exploratory factor analysis availed 2 components accounting for 21 and 17% and consisting of separate individual movements (shoulder mobility and deep squat, respectively). Analysis on scores discounting pain showed similar results. The factor structures were not interpretable, and the low Cronbach's alpha suggests a lack of internal consistency in FMS sum scores. Results do not offer support for validity of the FMS sum score as a unidimensional construct. In the absence of additional psychometric research, caution is warranted when using the FMS sum score.

Examination of the neighborhood activation theory in normal and hearing-impaired listeners.

PubMed

Dirks, D D; Takayanagi, S; Moshfegh, A; Noffsinger, P D; Fausti, S A

2001-02-01

Experiments were conducted to examine the effects of lexical information on word recognition among normal hearing listeners and individuals with sensorineural hearing loss. The lexical factors of interest were incorporated in the Neighborhood Activation Model (NAM). Central to this model is the concept that words are recognized relationally in the context of other phonemically similar words. NAM suggests that words in the mental lexicon are organized into similarity neighborhoods and the listener is required to select the target word from competing lexical items. Two structural characteristics of similarity neighborhoods that influence word recognition have been identified; "neighborhood density" or the number of phonemically similar words (neighbors) for a particular target item and "neighborhood frequency" or the average frequency of occurrence of all the items within a neighborhood. A third lexical factor, "word frequency" or the frequency of occurrence of a target word in the language, is assumed to optimize the word recognition process by biasing the system toward choosing a high frequency over a low frequency word. Three experiments were performed. In the initial experiments, word recognition for consonant-vowel-consonant (CVC) monosyllables was assessed in young normal hearing listeners by systematically partitioning the items into the eight possible lexical conditions that could be created by two levels of the three lexical factors, word frequency (high and low), neighborhood density (high and low), and average neighborhood frequency (high and low). Neighborhood structure and word frequency were estimated computationally using a large, on-line lexicon-based Webster's Pocket Dictionary. From this program 400 highly familiar, monosyllables were selected and partitioned into eight orthogonal lexical groups (50 words/group). The 400 words were presented randomly to normal hearing listeners in speech-shaped noise (Experiment 1) and "in quiet" (Experiment 2) as well as to an elderly group of listeners with sensorineural hearing loss in the speech-shaped noise (Experiment 3). The results of three experiments verified predictions of NAM in both normal hearing and hearing-impaired listeners. In each experiment, words from low density neighborhoods were recognized more accurately than those from high density neighborhoods. The presence of high frequency neighbors (average neighborhood frequency) produced poorer recognition performance than comparable conditions with low frequency neighbors. Word frequency was found to have a highly significant effect on word recognition. Lexical conditions with high word frequencies produced higher performance scores than conditions with low frequency words. The results supported the basic tenets of NAM theory and identified both neighborhood structural properties and word frequency as significant lexical factors affecting word recognition when listening in noise and "in quiet." The results of the third experiment permit extension of NAM theory to individuals with sensorineural hearing loss. Future development of speech recognition tests should allow for the effects of higher level cognitive (lexical) factors on lower level phonemic processing.

A cross-national study on the multidimensional characteristics of the five-item psychological demands scale of the Job Content Questionnaire.

PubMed

Choi, BongKyoo; Kawakami, Norito; Chang, SeiJin; Koh, SangBaek; Bjorner, Jakob; Punnett, Laura; Karasek, Robert

2008-01-01

The five-item psychological demands scale of the Job Content Questionnaire (JCQ) has been assumed to be one-dimensional in practice. To examine whether the scale has sufficient internal consistency and external validity to be treated as a single scale, using the cross-national JCQ datasets from the United States, Korea, and Japan. Exploratory factor analyses with 22 JCQ items, confirmatory factor analyses with the five psychological demands items, and correlations analyses with mental health indexes. Generally, exploratory factor analyses displayed the predicted demand/control/support structure with three and four factors extracted. However, at more detailed levels of exploratory and confirmatory factor analyses, the demands scale showed clear evidence of multi-factor structure. The correlations of items and subscales of the demands scale with mental health indexes were similar to those of the full scale in the Korean and Japanese datasets, but not in the U.S. data. In 4 out of 16 sub-samples of the U.S. data, several significant correlations of the components of the demands scale with job dissatisfaction and life dissatisfaction were obscured by the full scale. The multidimensionality of the psychological demands scale should be considered in psychometric analysis and interpretation, occupational epidemiologic studies, and future scale extension.

A structural and functional comparison of gap junction channels composed of connexins and innexins

PubMed Central

Williams, Jamal B.

2016-01-01

ABSTRACT Methods such as electron microscopy and electrophysiology led to the understanding that gap junctions were dense arrays of channels connecting the intracellular environments within almost all animal tissues. The characteristics of gap junctions were remarkably similar in preparations from phylogenetically diverse animals such as cnidarians and chordates. Although few studies directly compared them, minor differences were noted between gap junctions of vertebrates and invertebrates. For instance, a slightly wider gap was noted between cells of invertebrates and the spacing between invertebrate channels was generally greater. Connexins were identified as the structural component of vertebrate junctions in the 1980s and innexins as the structural component of pre‐chordate junctions in the 1990s. Despite a lack of similarity in gene sequence, connexins and innexins are remarkably similar. Innexins and connexins have the same membrane topology and form intercellular channels that play a variety of tissue‐ and temporally specific roles. Both protein types oligomerize to form large aqueous channels that allow the passage of ions and small metabolites and are regulated by factors such as pH, calcium, and voltage. Much more is currently known about the structure, function, and structure–function relationships of connexins. However, the innexin field is expanding. Greater knowledge of innexin channels will permit more detailed comparisons with their connexin‐based counterparts, and provide insight into the ubiquitous yet specific roles of gap junctions. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 522–547, 2017 PMID:27582044

A proximity-based graph clustering method for the identification and application of transcription factor clusters.

PubMed

Spadafore, Maxwell; Najarian, Kayvan; Boyle, Alan P

2017-11-29

Transcription factors (TFs) form a complex regulatory network within the cell that is crucial to cell functioning and human health. While methods to establish where a TF binds to DNA are well established, these methods provide no information describing how TFs interact with one another when they do bind. TFs tend to bind the genome in clusters, and current methods to identify these clusters are either limited in scope, unable to detect relationships beyond motif similarity, or not applied to TF-TF interactions. Here, we present a proximity-based graph clustering approach to identify TF clusters using either ChIP-seq or motif search data. We use TF co-occurrence to construct a filtered, normalized adjacency matrix and use the Markov Clustering Algorithm to partition the graph while maintaining TF-cluster and cluster-cluster interactions. We then apply our graph structure beyond clustering, using it to increase the accuracy of motif-based TFBS searching for an example TF. We show that our method produces small, manageable clusters that encapsulate many known, experimentally validated transcription factor interactions and that our method is capable of capturing interactions that motif similarity methods might miss. Our graph structure is able to significantly increase the accuracy of motif TFBS searching, demonstrating that the TF-TF connections within the graph correlate with biological TF-TF interactions. The interactions identified by our method correspond to biological reality and allow for fast exploration of TF clustering and regulatory dynamics.

Social network types and well-being among South Korean older adults.

PubMed

Park, Sojung; Smith, Jacqui; Dunkle, Ruth E

2014-01-01

The social networks of older individuals reflect personal life history and cultural factors. Despite these two sources of variation, four similar network types have been identified in Europe, North America, Japan, and China: namely 'restricted', 'family', 'friend', and 'diverse'. This study identified the social network types of Korean older adults and examined differential associations of the network types with well-being. The analysis used data from the 2008 wave of the Korean Longitudinal Study of Aging (KLoSA: N = 4251, age range 65-108). We used a two-step cluster analytical approach to identify network types from seven indicators of network structure and function. Regression models determined associations between network types and well-being outcomes, including life satisfaction and depressive symptomatology. Cluster analysis of indicators of network structure and function revealed four types, including the restricted, friend, and diverse types. Instead of a family type, we found a couple-focused type. The young-old (age 65-74) were more likely to be in the couple-focused type and more of the oldest old (age 85+) belonged to the restricted type. Compared with the restricted network, older adults in all other networks were more likely to report higher life satisfaction and lower depressive symptomatology. Life course and cohort-related factors contribute to similarities across societies in network types and their associations with well-being. Korean-specific life course and socio-historical factors, however, may contribute to our unique findings about network types.

Longitudinal factorial invariance of the PedsQL 4.0 Generic Core Scales child self-report Version: one year prospective evidence from the California State Children's Health Insurance Program (SCHIP).

PubMed

Varni, James W; Limbers, Christine A; Newman, Daniel A; Seid, Michael

2008-11-01

The measurement of health-related quality of life (HRQOL) in pediatric medicine and health services research has grown significantly over the past decade. The paradigm shift toward patient-reported outcomes (PROs) has provided the opportunity to emphasize the value and critical need for pediatric patient self-report. In order for changes in HRQOL/PRO outcomes to be meaningful over time, it is essential to demonstrate longitudinal factorial invariance. This study examined the longitudinal factor structure of the PedsQL 4.0 Generic Core Scales over a one-year period for child self-report ages 5-17 in 2,887 children from a statewide evaluation of the California State Children's Health Insurance Program (SCHIP) utilizing a structural equation modeling framework. Specifying four- and five-factor measurement models, longitudinal structural equation modeling was used to compare factor structures over a one-year interval on the PedsQL 4.0 Generic Core Scales. While the four-factor conceptually-derived measurement model for the PedsQL 4.0 Generic Core Scales produced an acceptable fit, the five-factor empirically-derived measurement model from the initial field test of the PedsQL 4.0 Generic Core Scales produced a marginally superior fit in comparison to the four-factor model. For the five-factor measurement model, the best fitting model, strict factorial invariance of the PedsQL 4.0 Generic Core Scales across the two measurement occasions was supported by the stability of the comparative fit index between the unconstrained and constrained models, and several additional indices of practical fit including the root mean squared error of approximation, the non-normed fit index, and the parsimony normed fit index. The findings support an equivalent factor structure on the PedsQL 4.0 Generic Core Scales over time. Based on these data, it can be concluded that over a one-year period children in our study interpreted items on the PedsQL 4.0 Generic Core Scales in a similar manner.

Effect of the deletion of the C region on the structure and hydration of insulin-like growth factor 1: a molecular dynamics investigation

NASA Astrophysics Data System (ADS)

Degreve, Leo; Silva, Luciene B.

The structure and hydration of insulin-like growth factor 1 and an inactive mutant lacking the C region have been investigated in aqueous solution by molecular dynamics simulation. The overall structures of the two polypeptide resemble those determined by NMR spectroscopy. The deletion of the C region in the wild polypeptide introduces structural stability in the mutant, leading to a better definition of the secondary structure elements. A detailed hydration analysis was performed using the radial distribution functions and energy distributions. The backbone of the mutant is in general more solvent accessible than the wild polypeptide backbone. The structural rearrangements induced in the mutant led to changes in the solvent exposition of Tyr24 and Tyr60, which are residues important for ligand-receptor complex formation. Tyr24 exhibited a similar degree of solvent exposition in both IGF-1 and in the mutant; however, its hydroxyl group in the wild polypeptide is better solvated than in the mutant. Tyr60 was found to be solvent exposed in the wild protein, while in the mutant the involvement of its hydroxyl group in intramolecular hydrogen bonds led to it being buried away from the solvent.

Emotional and Behavioral Problems among Impoverished Kenyan Youth: Factor Structure and Sex-Differences

PubMed Central

Harder, Valerie S.; Mutiso, Victoria N.; Khasakhala, Lincoln I.; Burke, Heather M.; Rettew, David C.; Ivanova, Masha Y.; Ndetei, David M.

2014-01-01

Data on youth emotional and behavioral problems from societies in Sub-Saharan Africa are lacking. This may be due to the fact that few youth mental health assessments have been tested for construct validity of syndrome structure across multicultural societies that include developing countries, and almost none have been tested in Sub-Saharan Africa. The Youth Self-Report (YSR), for example, has shown great consistency of its syndrome structure across many cultures, yet data from only one developing country in Sub-Saharan Africa have been included. In this study, we test the factor structure of YSR syndromes among Kenyan youth ages 11–18 years from an informal settlement in Nairobi, Kenya and examine sex-differences in levels of emotional and behavioral problems. We find the eight syndrome structure of the YSR to fit these data well (Root Mean Square Error of Approximation=.049). While Kenyan girls have significantly higher internalizing (Anxious/Depressed, Withdrawn/Depressed, Somatic) problem scores than boys, these differences are of similar magnitude to published multicultural findings. The results support the generalizability of the YSR syndrome structure to Kenyan youth and are in line with multicultural findings supporting the YSR as an assessment of emotional and behavioral problems in diverse societies. PMID:25419046

Factors Important for Work Participation Among Older Workers with Depression, Cardiovascular Disease, and Osteoarthritis: A Mixed Method Study.

PubMed

Boot, Cécile R L; de Kruif, Anja Th C M; Shaw, William S; van der Beek, Allard J; Deeg, Dorly J; Abma, Tineke

2016-06-01

Purpose The aim of this study was to gain insight into differences and similarities in factors important for work participation in older (58-65 years) workers among three different chronic diseases: depression (D), cardiovascular disease (C), and osteoarthritis (O). Methods A mixed method design was used, with a qualitative part (in-depth interviews) with 14 patients with D, C or O and a quantitative part based on the 2002-2003 cohort of the Longitudinal Aging Study Amsterdam. We analysed and compared 3-year (response 93 %) predictors of paid work in 239 participants with D, C, or O using regression analyses. The qualitative findings were integrated with the quantitative findings aiming at complementarity. Results Common factors important for work participation were: working at baseline; male gender; lower age; partner with paid work; better physical and mental health; and higher mastery scores. The qualitative analyses added autonomy in work and provided contextual information regarding the perceived importance of working as factors important for participation in paid work. For D and C, work gave purpose in life and enhanced social contacts. Participation in work was perceived as necessary to structure life only for D. Conclusion Most factors important for work participation were similar for D, C, and O. However, the interviews revealed that for D, the context and the meaning attributed to these factors differed.

Validation of the MOS Social Support Survey 6-item (MOS-SSS-6) measure with two large population-based samples of Australian women.

PubMed

Holden, Libby; Lee, Christina; Hockey, Richard; Ware, Robert S; Dobson, Annette J

2014-12-01

This study aimed to validate a 6-item 1-factor global measure of social support developed from the Medical Outcomes Study Social Support Survey (MOS-SSS) for use in large epidemiological studies. Data were obtained from two large population-based samples of participants in the Australian Longitudinal Study on Women's Health. The two cohorts were aged 53-58 and 28-33 years at data collection (N = 10,616 and 8,977, respectively). Items selected for the 6-item 1-factor measure were derived from the factor structure obtained from unpublished work using an earlier wave of data from one of these cohorts. Descriptive statistics, including polychoric correlations, were used to describe the abbreviated scale. Cronbach's alpha was used to assess internal consistency and confirmatory factor analysis to assess scale validity. Concurrent validity was assessed using correlations between the new 6-item version and established 19-item version, and other concurrent variables. In both cohorts, the new 6-item 1-factor measure showed strong internal consistency and scale reliability. It had excellent goodness-of-fit indices, similar to those of the established 19-item measure. Both versions correlated similarly with concurrent measures. The 6-item 1-factor MOS-SSS measures global functional social support with fewer items than the established 19-item measure.

The Structure of Resting Bacterial Populations in Soil and Subsoil Permafrost

NASA Astrophysics Data System (ADS)

Soina, Vera S.; Mulyukin, Andrei L.; Demkina, Elena V.; Vorobyova, Elena A.; El-Registan, Galina I.

2004-09-01

The structure of individual cells in microbial populations in situ of the Arctic and Antarctic permafrost was studied by scanning and transmission electron microscopy methods and compared with that of cyst-like resting forms generated under special conditions by the non-sporeforming bacteria Arthrobacter and Micrococcus isolated from the permafrost. Electron microscopy examination of microorganisms in situ revealed several types of bacterial cells having no signs of damage, including "dwarf" curved forms similar to nanoforms. Intact bacterial cells in situ and frozen cultures of the permafrost isolates differed from vegetative cells by thickened cell walls, the altered structure of cytoplasm, and the compact nucleoid, and were similar in these features to cyst-like resting forms of non-spore-forming "permafrost" bacterial strains of Arthrobacter and Micrococcus spp. Cyst-like cells, being resistant to adverse external factors, are regarded as being responsible for survival of the non-spore-formers under prolonged exposure to subzero temperatures and can be a target to search for living microorganisms in natural environments both on the Earth and on extraterrestrial bodies.

Identifying similar and different factors effecting long-term cardiac exercise rehabilitation behavior modification between New Zealand and the United Kingdom.

PubMed

Dunn, Stephanie; Lark, Sally; Fallows, Stephen

2014-07-01

Cardiac Rehabilitation (CR) programs are the most cost-effective measure for reducing morbidity associated with Coronary Vascular Disease (CVD). To be more effective there is a need to understand what influences the maintenance of healthy behaviors. This study identifies similar and different influences in CR of the United Kingdom (UK) and New Zealand (NZ). A retrospective study. Participants had previously been discharged from CR for 6 to 12+ months within the UK (n = 22) and NZ (n = 21). Participant's attended a focus group. Discussions were digitally recorded, transcribed then thematically analyzed. The CR programs were observed over 2 months to enable comment on findings relating to 'theory in practice.' Similar positive patient experiences influencing behavior between groups and countries were; support, education, positive attitude, and motivation. Companionship and exercising alongside people with similar health problems was the major determinant for positive exercise behavior. Barriers to maintaining exercise included; physical disabilities, time constraints, and weather conditions. NZ participants were more affected by external factors (eg, opportunity, access, and time). Both CR programs were successful in facilitating the maintenance of healthy lifestyles. Exercising with other cardiac patients for support in a structured environment was the strongest influence in maintaining healthy lifestyles beyond CR programs.

Universal behavior of the γ⁎γ→(π0,η,η′) transition form factors

PubMed Central

Melikhov, Dmitri; Stech, Berthold

2012-01-01

The photon transition form factors of π, η and η′ are discussed in view of recent measurements. It is shown that the exact axial anomaly sum rule allows a precise comparison of all three form factors at high-Q2 independent of the different structures and distribution amplitudes of the participating pseudoscalar mesons. We conclude: (i) The πγ form factor reported by Belle is in excellent agreement with the nonstrange I=0 component of the η and η′ form factors obtained from the BaBar measurements. (ii) Within errors, the πγ form factor from Belle is compatible with the asymptotic pQCD behavior, similar to the η and η′ form factors from BaBar. Still, the best fits to the data sets of πγ, ηγ, and η′γ form factors favor a universal small logarithmic rise Q2FPγ(Q2)∼log(Q2). PMID:23226917

Ego-resiliency reloaded: a three-component model of general resiliency.

PubMed

Farkas, Dávid; Orosz, Gábor

2015-01-01

Ego-resiliency (ER) is a capacity that enables individuals to adapt to constantly changing environmental demands. The goal of our research was to identify components of Ego-resiliency, and to test the reliability and the structural and convergent validity of the refined version of the ER11 Ego-resiliency scale. In Study 1 we used a factor analytical approach to assess structural validity and to identify factors of Ego-resiliency. Comparing alternative factor-structures, a hierarchical model was chosen including three factors: Active Engagement with the World (AEW), Repertoire of Problem Solving Strategies (RPSS), and Integrated Performance under Stress (IPS). In Study 2, the convergent and divergent validity of the ER11 scale and its factors and their relationship with resilience were tested. The results suggested that resiliency is a double-faced construct, with one function to keep the personality system stable and intact, and the other function to adjust the personality system in an adaptive way to the dynamically changing environment. The stability function is represented by the RPSS and IPS components of ER. Their relationship pattern is similar to other constructs of resilience, e.g. the Revised Connor-Davidson Resilience Scale (R-CD-RISC). The flexibility function is represented by the unit of RPSS and AEW components. In Study 3 we tested ER11 on a Hungarian online representative sample and integrated the results in a model of general resiliency. This framework allows us to grasp both the stability-focused and the plasticity-focused nature of resiliency.

Ego-Resiliency Reloaded: A Three-Component Model of General Resiliency

PubMed Central

Farkas, Dávid; Orosz, Gábor

2015-01-01

Ego-resiliency (ER) is a capacity that enables individuals to adapt to constantly changing environmental demands. The goal of our research was to identify components of Ego-resiliency, and to test the reliability and the structural and convergent validity of the refined version of the ER11 Ego-resiliency scale. In Study 1 we used a factor analytical approach to assess structural validity and to identify factors of Ego-resiliency. Comparing alternative factor-structures, a hierarchical model was chosen including three factors: Active Engagement with the World (AEW), Repertoire of Problem Solving Strategies (RPSS), and Integrated Performance under Stress (IPS). In Study 2, the convergent and divergent validity of the ER11 scale and its factors and their relationship with resilience were tested. The results suggested that resiliency is a double-faced construct, with one function to keep the personality system stable and intact, and the other function to adjust the personality system in an adaptive way to the dynamically changing environment. The stability function is represented by the RPSS and IPS components of ER. Their relationship pattern is similar to other constructs of resilience, e.g. the Revised Connor-Davidson Resilience Scale (R-CD-RISC). The flexibility function is represented by the unit of RPSS and AEW components. In Study 3 we tested ER11 on a Hungarian online representative sample and integrated the results in a model of general resiliency. This framework allows us to grasp both the stability-focused and the plasticity-focused nature of resiliency. PMID:25815881

The Spinal Cord Injury- Functional Index: Item Banks to Measure Physical Functioning of Individuals with Spinal Cord Injury

PubMed Central

Tulsky, David S.; Jette, Alan; Kisala, Pamela A.; Kalpakjian, Claire; Dijkers, Marcel P.; Whiteneck, Gale; Ni, Pengsheng; Kirshblum, Steven; Charlifue, Susan; Heinemann, Allen W.; Forchheimer, Martin; Slavin, Mary; Houlihan, Bethlyn; Tate, Denise; Dyson-Hudson, Trevor; Fyffe, Denise; Williams, Steve; Zanca, Jeanne

2012-01-01

Objective To develop a comprehensive set of patient reported items to assess multiple aspects of physical functioning relevant to the lives of people with spinal cord injury (SCI) and to evaluate the underlying structure of physical functioning. Design Cross-sectional Setting Inpatient and community Participants Item pools of physical functioning were developed, refined and field tested in a large sample of 855 individuals with traumatic spinal cord injury stratified by diagnosis, severity, and time since injury Interventions None Main Outcome Measure SCI-FI measurement system Results Confirmatory factor analysis (CFA) indicated that a 5-factor model, including basic mobility, ambulation, wheelchair mobility, self care, and fine motor, had the best model fit and was most closely aligned conceptually with feedback received from individuals with SCI and SCI clinicians. When just the items making up basic mobility were tested in CFA, the fit statistics indicate strong support for a unidimensional model. Similar results were demonstrated for each of the other four factors indicating unidimensional models. Conclusions Though unidimensional or 2-factor (mobility and upper extremity) models of physical functioning make up outcomes measures in the general population, the underlying structure of physical function in SCI is more complex. A 5-factor solution allows for comprehensive assessment of key domain areas of physical functioning. These results informed the structure and development of the SCI-FI measurement system of physical functioning. PMID:22609299

The Aftercare and School Observation System (ASOS): Reliability and Component Structure.

PubMed

Ingoldsby, Erin M; Shelleby, Elizabeth C; Lane, Tonya; Shaw, Daniel S; Dishion, Thomas J; Wilson, Melvin N

2013-10-01

This study examines the psychometric properties and component structure of a newly developed observational system, the Aftercare and School Observation System (ASOS). Participants included 468 children drawn from a larger longitudinal intervention study. The system was utilized to assess participant children in school lunchrooms and recess and various afterschool environments. Exploratory factor analyses examined whether a core set of component constructs assessing qualities of children's relationships, caregiver involvement and monitoring, and experiences in school and aftercare contexts that have been linked to children's behavior problems would emerge. Construct validity was assessed by examining associations between ASOS constructs and questionnaire measures assessing children's behavior problems and relationship qualities in school and aftercare settings. Across both settings, two factors showed very similar empirical structures and item loadings, reflecting the constructs of a negative/aggressive context and caregiver positive involvement, with one additional unique factor from the school setting reflecting the extent to which caregiver methods used resulted in less negative behavior and two additional unique factors from the aftercare setting reflecting positivity in the child's interactions and general environment and negativity in the child's interactions and setting. Modest correlations between ASOS factors and aftercare provider and teacher ratings of behavior problems, adult-child relationships, and a rating of school climate contributed to our interpretation that the ASOS scores capture meaningful features of children's experiences in these settings. This study represents the first step of establishing that the ASOS reliably and validly captures risk and protective relationships and experiences in extra-familial settings.

Community structure of grassland ground-dwelling arthropods along increasing soil salinities.

PubMed

Pan, Chengchen; Feng, Qi; Liu, Jiliang; Li, Yulin; Li, Yuqiang; Yu, Xiaoya

2018-03-01

Ground-dwelling arthropod communities are influenced by numerous biotic and abiotic factors. Little is known, however, about the relative importance of vegetation structure and abiotic environmental factors on the patterns of ground-dwelling arthropod community across a wide range of soil salinities. Here, a field survey was conducted to assess the driving forces controlling ground-dwelling arthropod community in the salinized grasslands in the Hexi Corridor, Gansu Province, China. The data were analyzed by variance partitioning with canonical correspondence analysis (CCA). We found that vegetation structure and edaphic factors were at least of similar importance to the pattern of the whole ground-dwelling arthropod community. However, when all collected ground-dwelling arthropods were categorized into three trophic guilds (predators, herbivores, and decomposers), as these groups use different food sources, their populations were controlled by different driving forces. Predators and decomposers were mainly determined by biotic factors such as vegetation cover and aboveground plant biomass and herbivores by plant density and vegetation cover. Abiotic factors were also major determinants for the variation occurring in these guilds, with predators strongly affected by soil electrical conductivity (EC) and the content of fine particles (silt + clay, CS), herbivores by soil N:P, EC, and CS, and decomposers by soil EC and organic matter content (SOM). Since plant cover, density, and aboveground biomass can indicate resource availability, which are mainly constrained by soil N:P, EC, CS, and SOM, we consider that the ground-dwelling arthropod community in the salinized grasslands was mainly influenced by resource availability.

Structural differences within negative and depressive syndrome dimensions in schizophrenia, organic brain disease, and major depression: A confirmatory factor analysis of the positive and negative syndrome scale.

PubMed

Eisenberg, Daniel P; Aniskin, Dmitry B; White, Leonard; Stein, Judith A; Harvey, Philip D; Galynker, Igor I

2009-01-01

The emerging dimensional approach to classification and treatment of psychiatric disorders calls for better understanding of diagnosis-related variations in psychiatric syndromes and for proper validation of psychometric scales used for the evaluation of those syndromes. This study tested the hypothesis that negative and depressive syndromes as measured by the Positive and Negative Syndrome Scale (PANSS) are consistent across different diagnoses. We administered the PANSS to subjects with schizophrenia (n = 305), organic brain disease (OBD, n = 66) and major depressive disorder (MDD, n = 75). Confirmatory factor analysis (CFA) was used to establish if the PANSS items for negative symptoms and for depression fit the hypothesized factor structure and if the item factor loadings were similar among the diagnostic groups. The negative and depressive symptom subscales fit well according to a variety of fit indexes for all groups individually after some modest model modification. However, multisample modeling procedures indicated that the pattern of factor loadings was significantly different among the groups in most cases. The results of this study indicate diagnosis-related variations in the negative and depressive syndrome dimensions in schizophrenia, OBD and MDD. These results also validate limited use of the PANSS for evaluation of negative and depressive syndromes in disorders other than schizophrenia. Larger studies are warranted to further evaluate clinical and nosologic significance of diagnostic categories, dimensions and structures of psychiatric syndromes. 2009 S. Karger AG, Basel.

Igs expressed by chronic lymphocytic leukemia B cells show limited binding-site structure variability.

PubMed

Marcatili, Paolo; Ghiotto, Fabio; Tenca, Claudya; Chailyan, Anna; Mazzarello, Andrea N; Yan, Xiao-Jie; Colombo, Monica; Albesiano, Emilia; Bagnara, Davide; Cutrona, Giovanna; Morabito, Fortunato; Bruno, Silvia; Ferrarini, Manlio; Chiorazzi, Nicholas; Tramontano, Anna; Fais, Franco

2013-06-01

Ag selection has been suggested to play a role in chronic lymphocytic leukemia (CLL) pathogenesis, but no large-scale analysis has been performed so far on the structure of the Ag-binding sites (ABSs) of leukemic cell Igs. We sequenced both H and L chain V(D)J rearrangements from 366 CLL patients and modeled their three-dimensional structures. The resulting ABS structures were clustered into a small number of discrete sets, each containing ABSs with similar shapes and physicochemical properties. This structural classification correlates well with other known prognostic factors such as Ig mutation status and recurrent (stereotyped) receptors, but it shows a better prognostic value, at least in the case of one structural cluster for which clinical data were available. These findings suggest, for the first time, to our knowledge, on the basis of a structural analysis of the Ab-binding sites, that selection by a finite quota of antigenic structures operates on most CLL cases, whether mutated or unmutated.

DNA replication in the archaea.

PubMed

Barry, Elizabeth R; Bell, Stephen D

2006-12-01

The archaeal DNA replication machinery bears striking similarity to that of eukaryotes and is clearly distinct from the bacterial apparatus. In recent years, considerable advances have been made in understanding the biochemistry of the archaeal replication proteins. Furthermore, a number of structures have now been obtained for individual components and higher-order assemblies of archaeal replication factors, yielding important insights into the mechanisms of DNA replication in both archaea and eukaryotes.

Factorial and Hierarchical Cluster Analysis of the Adaptive Behavior Scales (Part I & II) in a Population of Older People (50 Years +) with Severe Intellectual Impairment (Mental Handicap).

ERIC Educational Resources Information Center

Moss, S. C.; Hogg, J.

1990-01-01

Principal components analysis was employed on the Adaptive Behavior Scales with scores of 122 older (mean age 63.5) individuals with severe intellectual impairment living in England. The study found the structure of adaptive skills and interpersonal maladaptive behaviors similar to that found for younger retarded adults. Two factors, personal…

Modeling Insurgency, Counter-Insurgency, and Coalition Strategies and Operations

DTIC Science & Technology

2012-01-01

these structures to analyze the components of leadership, promotion , recruitment, financial resources, operational techniques, network communications...processes into account: promotion of junior leaders (j), loss of senior leaders to internal factors (l), recruitment of senior leaders (o), rate that senior...is modeled in a similar manner as senior lead- ers, using: promotion of foot soldiers to junior leaders (β1f), the loss of junior leaders promoted to

Sequence-similar, structure-dissimilar protein pairs in the PDB.

PubMed

Kosloff, Mickey; Kolodny, Rachel

2008-05-01

It is often assumed that in the Protein Data Bank (PDB), two proteins with similar sequences will also have similar structures. Accordingly, it has proved useful to develop subsets of the PDB from which "redundant" structures have been removed, based on a sequence-based criterion for similarity. Similarly, when predicting protein structure using homology modeling, if a template structure for modeling a target sequence is selected by sequence alone, this implicitly assumes that all sequence-similar templates are equivalent. Here, we show that this assumption is often not correct and that standard approaches to create subsets of the PDB can lead to the loss of structurally and functionally important information. We have carried out sequence-based structural superpositions and geometry-based structural alignments of a large number of protein pairs to determine the extent to which sequence similarity ensures structural similarity. We find many examples where two proteins that are similar in sequence have structures that differ significantly from one another. The source of the structural differences usually has a functional basis. The number of such proteins pairs that are identified and the magnitude of the dissimilarity depend on the approach that is used to calculate the differences; in particular sequence-based structure superpositioning will identify a larger number of structurally dissimilar pairs than geometry-based structural alignments. When two sequences can be aligned in a statistically meaningful way, sequence-based structural superpositioning provides a meaningful measure of structural differences. This approach and geometry-based structure alignments reveal somewhat different information and one or the other might be preferable in a given application. Our results suggest that in some cases, notably homology modeling, the common use of nonredundant datasets, culled from the PDB based on sequence, may mask important structural and functional information. We have established a data base of sequence-similar, structurally dissimilar protein pairs that will help address this problem (http://luna.bioc.columbia.edu/rachel/seqsimstrdiff.htm).

An Indian adaptation of the Involvement Evaluation Questionnaire: similarities and differences in assessment of caregiver burden.

PubMed

Grover, S; Chakrabarti, S; Ghormode, D; Dutt, A; Kate, N; Kulhara, P

2011-12-01

The Involvement Evaluation Questionnaire (IEQ) is a comprehensive, conceptually valid and reliable means of assessing caregiver burden. However, its psychometric properties have rarely been examined in non-European settings. The aim of the present study was to evaluate the psychometric properties of an Indian translation of the IEQ (Hindi-IEQ). The European Union (English) version of IEQ was translated into Hindi and reviewed by a group of experts and caregivers for translation accuracy, cultural appropriateness, and for relevance and acceptability of items and constructs. The Hindi-IEQ was then administered to 162 primary caregivers of patients with severe mental illnesses. Eighteen caregivers completed both the English and Hindi versions to check the level of agreement between them. Another 27 completed the Hindi-IEQ twice, a week apart, to evaluate its test-retest reliability. Factor structure of the Hindi-IEQ was examined using an exploratory, principal components and factor analysis. Pearson's correlation coefficients were significant for 24 items, while intraclass correlation coefficients were significant for 28 of the 31 items (P < 0.05), indicating a satisfactory level of agreement between the Hindi and English versions. Test-retest reliability for all items of the Hindi-IEQ was adequate, with kappa values ranging from 0.46 to 0.95 and intraclass correlation coefficients from 0.76 to 1.00. Internal consistency (Cronbach's alpha = 0.89) and the split-half reliability (Spearman-Brown coefficient = 0.68) of the Hindi-IEQ were also satisfactory. However, several differences were noted in the factor structure and distribution of scores of the Hindi-IEQ, which were quite unlike that of the European Union version. The similarities and differences between the 2 versions of the IEQ indicated that sociocultural factors could influence assessment of caregiver burden across different cultures.

Validation of the Chronic Pain Acceptance Questionnaire-8 in an Australian pain clinic sample.

PubMed

Baranoff, John; Hanrahan, Stephanie J; Kapur, Dilip; Connor, Jason P

2014-02-01

Recently, an 8-item short-form version of the Chronic Pain Acceptance Questionnaire (CPAQ-8) was developed predominantly in an internet sample. Further investigation of the factor structure in a multidisciplinary pain clinic sample is required. Investigation of the concurrent validity of the CPAQ-8 after accounting for the effects of variables commonly measured in the pain clinic setting is also necessary. This study examines the factor structure and concurrent validity of the CPAQ-8 in a sample of treatment-seeking patients who attended a multidisciplinary pain clinic. Participants were 334 patients who attended an Australian multidisciplinary pain service. Participants completed the CPAQ, a demographic questionnaire, and measures of patient adjustment and functioning. Confirmatory factor analysis identified a two-factor 8-item model consisting of Activity Engagement and Pain Willingness factors (SRMR = 0.039, RMSEA = 0.063, CFI = 0.973, TLI = 0.960) was superior to both the CPAQ and CPAQ with an item removed. The CPAQ and CPAQ-8 total scores were highly correlated (r = 0.93). After accounting for pain intensity, the CPAQ-8 was a significant predictor of depression, anxiety, stress, and disability. The subscales of the CPAQ-8 were both unique contributors to depression and disability in regression analyses, after accounting for pain intensity and kinesiophobia, and after accounting for pain intensity and catastrophizing. The CPAQ-8 has a sound factor structure and similar psychometric properties to the CPAQ; it may have clinical utility as a measure of pain acceptance in treatment-seeking, chronic pain patients.

Developing a systems-based framework of the factors influencing dietary and physical activity behaviours in ethnic minority populations living in Europe - a DEDIPAC study.

PubMed

Holdsworth, Michelle; Nicolaou, Mary; Langøien, Lars Jørun; Osei-Kwasi, Hibbah Araba; Chastin, Sebastien F M; Stok, F Marijn; Capranica, Laura; Lien, Nanna; Terragni, Laura; Monsivais, Pablo; Mazzocchi, Mario; Maes, Lea; Roos, Gun; Mejean, Caroline; Powell, Katie; Stronks, Karien

2017-11-07

Some ethnic minority populations have a higher risk of non-communicable diseases than the majority European population. Diet and physical activity behaviours contribute to this risk, shaped by a system of inter-related factors. This study mapped a systems-based framework of the factors influencing dietary and physical activity behaviours in ethnic minority populations living in Europe, to inform research prioritisation and intervention development. A concept mapping approach guided by systems thinking was used: i. Preparation (protocol and terminology); ii. Generating a list of factors influencing dietary and physical activity behaviours in ethnic minority populations living in Europe from evidence (systematic mapping reviews) and 'eminence' (89 participants from 24 academic disciplines via brainstorming, an international symposium and expert review) and; iii. Seeking consensus on structuring, rating and clustering factors, based on how they relate to each other; and iv. Interpreting/utilising the framework for research and interventions. Similar steps were undertaken for frameworks developed for the majority European population. Seven distinct clusters emerged for dietary behaviour (containing 85 factors) and 8 for physical activity behaviours (containing 183 factors). Four clusters were similar across behaviours: Social and cultural environment; Social and material resources; Psychosocial; and Migration context. Similar clusters of factors emerged in the frameworks for diet and physical activity behaviours of the majority European population, except for 'migration context'. The importance of factors across all clusters was acknowledged, but their relative importance differed for ethnic minority populations compared with the majority population. This systems-based framework integrates evidence from both expert opinion and published literature, to map the factors influencing dietary and physical activity behaviours in ethnic minority groups. Our findings illustrate that innovative research and complex interventions need to be developed that are sensitive to the needs of ethnic minority populations. A systems approach that encompasses the complexity of the inter-related factors that drive behaviours may inform a more holistic public health paradigm to more effectively reach ethnic minorities living in Europe, as well as the majority host population.

Structure of Rot, a global regulator of virulence genes in Staphylococcus aureus.

PubMed

Zhu, Yuwei; Fan, Xiaojiao; Zhang, Xu; Jiang, Xuguang; Niu, Liwen; Teng, Maikun; Li, Xu

2014-09-01

Staphylococcus aureus is a highly versatile pathogen that can infect human tissue by producing a large arsenal of virulence factors that are tightly regulated by a complex regulatory network. Rot, which shares sequence similarity with SarA homologues, is a global regulator that regulates numerous virulence genes. However, the recognition model of Rot for the promoter region of target genes and the putative regulation mechanism remain elusive. In this study, the 1.77 Å resolution X-ray crystal structure of Rot is reported. The structure reveals that two Rot molecules form a compact homodimer, each of which contains a typical helix-turn-helix module and a β-hairpin motif connected by a flexible loop. Fluorescence polarization results indicate that Rot preferentially recognizes AT-rich dsDNA with ~30-base-pair nucleotides and that the conserved positively charged residues on the winged-helix motif are vital for binding to the AT-rich dsDNA. It is proposed that the DNA-recognition model of Rot may be similar to that of SarA, SarR and SarS, in which the helix-turn-helix motifs of each monomer interact with the major grooves of target dsDNA and the winged motifs contact the minor grooves. Interestingly, the structure shows that Rot adopts a novel dimerization model that differs from that of other SarA homologues. As expected, perturbation of the dimer interface abolishes the dsDNA-binding ability of Rot, suggesting that Rot functions as a dimer. In addition, the results have been further confirmed in vivo by measuring the transcriptional regulation of α-toxin, a major virulence factor produced by most S. aureus strains.

Structural basis of mammalian glycan targeting by Vibrio cholerae cytolysin and biofilm proteins

PubMed Central

De, Swastik; Kaus, Katherine; Sinclair, Shada

2018-01-01

Vibrio cholerae is an aquatic gram-negative microbe responsible for cholera, a pandemic disease causing life-threatening diarrheal outbreaks in populations with limited access to health care. Like most pathogenic bacteria, V. cholerae secretes virulence factors to assist colonization of human hosts, several of which bind carbohydrate receptors found on cell-surfaces. Understanding how pathogenic virulence proteins specifically target host cells is important for the development of treatment strategies to fight bacterial infections. Vibrio cholerae cytolysin (VCC) is a secreted pore-forming toxin with a carboxy-terminal β-prism domain that targets complex N-glycans found on mammalian cell-surface proteins. To investigate glycan selectivity, we studied the VCC β-prism domain and two additional β-prism domains found within the V. cholerae biofilm matrix protein RbmC. We show that the two RbmC β-prism domains target a similar repertoire of complex N-glycan receptors as VCC and find through binding and modeling studies that a branched pentasaccharide core (GlcNAc2-Man3) represents the likely footprint interacting with these domains. To understand the structural basis of V. cholerae β-prism selectivity, we solved high-resolution crystal structures of fragments of the pentasaccharide core bound to one RbmC β-prism domain and conducted mutagenesis experiments on the VCC toxin. Our results highlight a common strategy for cell-targeting utilized by both toxin and biofilm matrix proteins in Vibrio cholerae and provide a structural framework for understanding the specificity for individual receptors. Our results suggest that a common strategy for disrupting carbohydrate interactions could affect multiple virulence factors produced by V. cholerae, as well as similar β-prism domains found in other vibrio pathogens. PMID:29432487

Structure and Spatial Distribution of the Chironomidae Community in Mesohabitats in a First Order Stream at the Poço D'Anta Municipal Biological Reserve in Brazil

PubMed Central

Vescovi Rosa, Beatriz Figueiraujo Jabour; de Oliveira, Vívian Campos; Alves, Roberto da Gama

2011-01-01

The Chironomidae occupy different habitats along the lotic system with their distribution determined by different factors such as the substrate characteristics and water speed. The input of vegetable material from the riparian forest allows a higher habitat diversity and food to the benthic fauna. The main aim of this paper is to verify the structure and spatial distribution of the Chironomidae fauna in different mesohabitats in a first order stream located at a Biological Reserve in the southeast of Brazil. In the months of July, August, and September 2007, and in January, February, and March 2008, samples were collected with a hand net (250 µm) in the following mesohabitats: litter from riffles, litter from pools, and sediment from pools. The community structure of each mesohabitat was analyzed through the abundance of organisms, taxa richness, Pielou's evenness, Shannon's diversity, and taxa dominance. Similarity among the mesohabitats was obtained by Cluster analysis, and Chironomidae larvae distribution through the Correspondence analysis. Indicator species analysis was used to identify possible taxa preference for a determined mesohabitat. The analyzed mesohabitats showed high species richness and diversity favored by the large environmental heterogeneity. Some taxa were indicators of the type of mesohabitat. The substrate was the main factor that determined taxa distribution in relation to water flow differences (riffle and pool). Stream characteristics such as low water speed and the presence of natural mechanisms of retention may have provided a higher faunistic similarity between the areas with different flows. The results showed that the physical characteristics of each environment presented a close relationship with the structure and spatial distribution of the Chironomidae fauna in lotic systems. PMID:21529258

What Happened, and Why: Toward an Understanding of Human Error Based on Automated Analyses of Incident Reports. Volume 1

NASA Technical Reports Server (NTRS)

Maille, Nicolas P.; Statler, Irving C.; Ferryman, Thomas A.; Rosenthal, Loren; Shafto, Michael G.; Statler, Irving C.

2006-01-01

The objective of the Aviation System Monitoring and Modeling (ASMM) project of NASA s Aviation Safety and Security Program was to develop technologies that will enable proactive management of safety risk, which entails identifying the precursor events and conditions that foreshadow most accidents. This presents a particular challenge in the aviation system where people are key components and human error is frequently cited as a major contributing factor or cause of incidents and accidents. In the aviation "world", information about what happened can be extracted from quantitative data sources, but the experiential account of the incident reporter is the best available source of information about why an incident happened. This report describes a conceptual model and an approach to automated analyses of textual data sources for the subjective perspective of the reporter of the incident to aid in understanding why an incident occurred. It explores a first-generation process for routinely searching large databases of textual reports of aviation incident or accidents, and reliably analyzing them for causal factors of human behavior (the why of an incident). We have defined a generic structure of information that is postulated to be a sound basis for defining similarities between aviation incidents. Based on this structure, we have introduced the simplifying structure, which we call the Scenario as a pragmatic guide for identifying similarities of what happened based on the objective parameters that define the Context and the Outcome of a Scenario. We believe that it will be possible to design an automated analysis process guided by the structure of the Scenario that will aid aviation-safety experts to understand the systemic issues that are conducive to human error.

Effects of Structural Properties of Electrospun TiO2 Nano-fiber Meshes on their Osteogenic Potential

PubMed Central

Wang, Xiaokun; Gittens, Rolando A.; Song, Rosemary; Tannenbaum, Rina; Olivares-Navarrete, Rene; Schwartz, Zvi; Chen, Haifeng; Boyan, Barbara D.

2011-01-01

Ideal outcomes in the field of tissue engineering and regenerative medicine involve biomaterials that can enhance cell differentiation and production of local factors for natural tissue regeneration without the use of systemic drugs. Biomaterials typically used in tissue engineering applications include polymeric scaffolds that mimic the 3-D structural environment of the native tissue, but these are often functionalized with proteins or small peptides to improve their biological performance. For bone applications, titanium (Ti) implants, or more appropriately the titania (TiO2) passive oxide layer formed on their surface, have been shown to enhance osteoblast differentiation in vitro and to promote osseointegration in vivo. In this study we evaluated the effect on osteoblast differentiation of pure TiO2 nano-fiber meshes with different surface micro-roughness and nano-fiber diameters, prepared by the electrospinning method. MG63 cells were seeded on TiO2 meshes, and cell number, differentiation markers and local factor production were analyzed. The results showed that cells grew throughout the entire surfaces and with similar morphology in all groups. Cell number was sensitive to surface micro-roughness, whereas cell differentiation and local factor production was regulated by both surface roughness and nano-fiber diameter. These results indicate that scaffold structural cues alone can be used to drive cell differentiation and create an osteogenic environment without the use of exogenous factors. PMID:22075122

Soil and plant factors driving the community of soil-borne microorganisms across chronosequences of secondary succession of chalk grasslands with a neutral pH.

PubMed

Kuramae, Eiko; Gamper, Hannes; van Veen, Johannes; Kowalchuk, George

2011-08-01

Although soil pH has been shown to be an important factor driving microbial communities, relatively little is known about the other potentially important factors that shape soil-borne microbial community structure. This study examined plant and microbial communities across a series of neutral pH fields (pH=7.0-7.5) representing a chronosequence of secondary succession after former arable fields were taken out of production. These fields ranged from 17 to >66 years since the time of abandonment, and an adjacent arable field was included as a reference. Hierarchical clustering analysis, nonmetric multidimensional scaling and analysis of similarity of 52 different plant species showed that the plant community composition was significantly different in the different chronosequences, and that plant species richness and diversity increased with time since abandonment. The microbial community structure, as analyzed by phylogenetic microarrays (PhyloChips), was significantly different in arable field and the early succession stage, but no distinct microbial communities were observed for the intermediate and the late succession stages. The most determinant factors in shaping the soil-borne microbial communities were phosphorous and NH(4)(+). Plant community composition and diversity did not have a significant effect on the belowground microbial community structure or diversity. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Psychometric evaluation of Persian Nomophobia Questionnaire: Differential item functioning and measurement invariance across gender.

PubMed

Lin, Chung-Ying; Griffiths, Mark D; Pakpour, Amir H

2018-03-01

Background and aims Research examining problematic mobile phone use has increased markedly over the past 5 years and has been related to "no mobile phone phobia" (so-called nomophobia). The 20-item Nomophobia Questionnaire (NMP-Q) is the only instrument that assesses nomophobia with an underlying theoretical structure and robust psychometric testing. This study aimed to confirm the construct validity of the Persian NMP-Q using Rasch and confirmatory factor analysis (CFA) models. Methods After ensuring the linguistic validity, Rasch models were used to examine the unidimensionality of each Persian NMP-Q factor among 3,216 Iranian adolescents and CFAs were used to confirm its four-factor structure. Differential item functioning (DIF) and multigroup CFA were used to examine whether males and females interpreted the NMP-Q similarly, including item content and NMP-Q structure. Results Each factor was unidimensional according to the Rach findings, and the four-factor structure was supported by CFA. Two items did not quite fit the Rasch models (Item 14: "I would be nervous because I could not know if someone had tried to get a hold of me;" Item 9: "If I could not check my smartphone for a while, I would feel a desire to check it"). No DIF items were found across gender and measurement invariance was supported in multigroup CFA across gender. Conclusions Due to the satisfactory psychometric properties, it is concluded that the Persian NMP-Q can be used to assess nomophobia among adolescents. Moreover, NMP-Q users may compare its scores between genders in the knowledge that there are no score differences contributed by different understandings of NMP-Q items.

The Dream Property Scale: an exploratory English version.

PubMed

Takeuchi, T; Ogilvie, R D; Ferrelli, A V; Murphy, T I; Belicki, K

2001-09-01

Our goal is to develop an English version of the Dream Property Scale (DPS-E) based on the original normed scale in Japan (DPS-J). Factor analyses extracted four factors (Emotionality, Rationality, Activity, and Impression) and its factor structure was apparently similar to the DPS-J. The DPS-E was also shown to be related to EEG power spectral values. These results indicate that the DPS-E may provide an exploratory basis for a reliable and valid tool for capturing and quantifying the properties of dream experiences that could reflect physiological activities without the intervention of experimenters. We suggest that the DPS-E will develop into a useful tool to help clarify dream production mechanisms by further investigation. Copyright 2001 Academic Press.

Development of the Social Capital Questionnaire in Greece.

PubMed

Kritsotakis, George; Koutis, Antonis D; Alegakis, Athanassios K; Philalithis, Anastas E

2008-06-01

The Greek version of the social capital questionnaire (SCQ-G) was evaluated in a sample of 521 adults drawn from three different urban areas in Greece. Exploratory factor analysis followed by multi-trait scaling yielded six factors: Participation in the Community, Feelings of Safety, Family/Friends Connections, Value of Life and Social Agency, Tolerance of Diversity, and Work Connections. The factor solution is similar to the patterns identified originally in Australia and the US. Variations suggest that social capital does not share the same structure in different countries. The SCQ-G is a useful scale to measure individual-level social capital in Greece. Social capital measurement tools should be validated in each cultural or national setting in which they are used.

The Psychometric Properties of the Generalized Anxiety Disorder-7 scale in Hispanic Americans with English or Spanish Language Preference

PubMed Central

Mills, Sarah D.; Fox, Rina S.; Malcarne, Vanessa L.; Roesch, Scott C.; Champagne, Brian R.; Sadler, Georgia Robins

2014-01-01

The Generalized Anxiety Disorder-7 scale (GAD-7) is a self-report questionnaire that is widely used to screen for anxiety. The GAD-7 has been translated into numerous languages, including Spanish. Previous studies evaluating the structural validity of the English and Spanish versions indicate a uni-dimensional factor structure in both languages. However, the psychometric properties of the Spanish language version have yet to be evaluated in samples outside of Spain, and the measure has not been tested for use among Hispanic Americans. This study evaluated the reliability, structural validity, and convergent validity of the English and Spanish language versions of the GAD-7 for Hispanic Americans in the United States. A community sample of 436 Hispanic Americans with an English (n = 210) or Spanish (n = 226) language preference completed the GAD-7. Multiple-group confirmatory factor analysis (CFA) was used to examine the goodness of fit of the uni-dimensional factor structure of the GAD-7 across language-preference groups. Results from the multiple-group CFA indicated a similar unidimensional factor structure with equivalent response patterns and item intercepts, but different variances, across language-preference groups. Internal consistency was good for both English and Spanish language-preference groups. The GAD-7 also evidenced good convergent validity as demonstrated by significant correlations in expected directions with the Perceived Stress Scale, the Patient Health Questionnaire-9, and the Physical health domain of the World Health Organization Quality of Life-BREF assessment. The uni-dimensional GAD-7 is suitable for use among Hispanic Americans with an English or Spanish language preference. PMID:25045957

Protein structure similarity from Principle Component Correlation analysis.

PubMed

Zhou, Xiaobo; Chou, James; Wong, Stephen T C

2006-01-25

Owing to rapid expansion of protein structure databases in recent years, methods of structure comparison are becoming increasingly effective and important in revealing novel information on functional properties of proteins and their roles in the grand scheme of evolutionary biology. Currently, the structural similarity between two proteins is measured by the root-mean-square-deviation (RMSD) in their best-superimposed atomic coordinates. RMSD is the golden rule of measuring structural similarity when the structures are nearly identical; it, however, fails to detect the higher order topological similarities in proteins evolved into different shapes. We propose new algorithms for extracting geometrical invariants of proteins that can be effectively used to identify homologous protein structures or topologies in order to quantify both close and remote structural similarities. We measure structural similarity between proteins by correlating the principle components of their secondary structure interaction matrix. In our approach, the Principle Component Correlation (PCC) analysis, a symmetric interaction matrix for a protein structure is constructed with relationship parameters between secondary elements that can take the form of distance, orientation, or other relevant structural invariants. When using a distance-based construction in the presence or absence of encoded N to C terminal sense, there are strong correlations between the principle components of interaction matrices of structurally or topologically similar proteins. The PCC method is extensively tested for protein structures that belong to the same topological class but are significantly different by RMSD measure. The PCC analysis can also differentiate proteins having similar shapes but different topological arrangements. Additionally, we demonstrate that when using two independently defined interaction matrices, comparison of their maximum eigenvalues can be highly effective in clustering structurally or topologically similar proteins. We believe that the PCC analysis of interaction matrix is highly flexible in adopting various structural parameters for protein structure comparison.

The secondary structure of the ets domain of human Fli-1 resembles that of the helix-turn-helix DNA-binding motif of the Escherichia coli catabolite gene activator protein.

PubMed Central

Liang, H; Olejniczak, E T; Mao, X; Nettesheim, D G; Yu, L; Thompson, C B; Fesik, S W

1994-01-01

The ets family of eukaryotic transcription factors is characterized by a conserved DNA-binding domain of approximately 85 amino acids for which the three-dimensional structure is not known. By using multidimensional NMR spectroscopy, we have determined the secondary structure of the ets domain of one member of this gene family, human Fli-1, both in the free form and in a complex with a 16-bp cognate DNA site. The secondary structure of the Fli-1 ets domain consists of three alpha-helices and a short four-stranded antiparallel beta-sheet. This secondary structure arrangement resembles that of the DNA-binding domain of the catabolite gene activator protein of Escherichia coli, as well as those of several eukaryotic DNA-binding proteins including histone H5, HNF-3/fork head, and the heat shock transcription factor. Differences in chemical shifts of backbone resonances and amide exchange rates between the DNA-bound and free forms of the Fli-1 ets domain suggest that the third helix is the DNA recognition helix, as in the catabolite gene activator protein and other structurally related proteins. These results suggest that the ets domain is structurally similar to the catabolite gene activator protein family of helix-turn-helix DNA-binding proteins. Images PMID:7972119

Surface Orientation Affects the Direction of Cone Growth by Leptolyngbya sp. Strain C1, a Likely Architect of Coniform Structures Octopus Spring (Yellowstone National Park)

PubMed Central

Reyes, Kristina; Gonzalez, Nicolas I.; Stewart, Joshua; Ospino, Frank; Nguyen, Dickie; Cho, David T.; Ghahremani, Nahal; Spear, John R.

2013-01-01

Laminated, microbially produced stromatolites within the rock record provide some of the earliest evidence for life on Earth. The chemical, physical, and biological factors that lead to the initiation of these organosedimentary structures and shape their morphology are unclear. Modern coniform structures with morphological features similar to stromatolites are found on the surface of cyanobacterial/microbial mats. They display a vertical element of growth, can have lamination, can be lithified, and observably grow with time. To begin to understand the microbial processes and interactions required for cone formation, we determined the phylogenetic composition of the microbial community of a coniform structure from a cyanobacterial mat at Octopus Spring, Yellowstone National Park, and reconstituted coniform structures in vitro. The 16S rRNA clone library from the coniform structure was dominated by Leptolyngbya sp. Other cyanobacteria and heterotrophic bacteria were present in much lower abundance. The same Leptolyngbya sp. identified in the clone library was also enriched in the laboratory and could produce cones in vitro. When coniform structures were cultivated in the laboratory, the initial incubation conditions were found to influence coniform morphology. In addition, both the angle of illumination and the orientation of the surface affected the angle of cone formation demonstrating how external factors can influence coniform, and likely, stromatolite morphology. PMID:23241986

Evidence for the Discriminant Validity of the Revised Social Anhedonia Scale From Social Anxiety.

PubMed

Cicero, David C; Krieg, Alexander; Becker, Theresa M; Kerns, John G

2016-10-01

Social anhedonia and social anxiety are two constructs with similar behaviors including avoidance of and withdrawal from social situations. In three studies, the current research aimed to test whether social anhedonia could be discriminated from social anxiety using the most common measure of social anhedonia, the Revised Social Anhedonia Scale (RSAS). In Study 1, an item-level factor analysis of the RSAS found two factors: Social Apathy/Aversion and Social Withdrawal. In Study 2, this two-factor structure was confirmed in a separate sample. In Study 3, a model with social anhedonia and anxiety scale scores loading on separate factors fit better than a model with social anhedonia and anxiety loading on a single factor. Social anhedonia and anxiety displayed differential associations with negative schizotypy and emotion processing. Findings suggest that the RSAS is successful in measuring social anhedonia distinct from social anxiety. © The Author(s) 2015.

Childhood obesity in America.

PubMed

Van Grouw, Jacqueline M; Volpe, Stella L

2013-10-01

To provide an overview of the current advances in childhood obesity physiology, intervention, and prevention. Structural and functional brain impairments are present in obese adolescents with metabolic syndrome (MetS). Aerobic training for 20 or 40 min per day produced similar affects on metabolic risk factors. Vitamin D supplementation has been shown to improve the metabolic risk factors in obese children; however, obese children require greater doses to treat vitamin D deficiency. A 10-week community-based exergaming weight management program significantly decreased the BMI in obese children. There is surmounting research on MetS and its associated risk factors in obese children. Gaining a comprehensive overview of the factors associated with obesity in children is crucial in developing the most effective intervention strategies. Community-based and family-centered interventions have generated positive results in reducing children's BMI and improving MetS risk factors. In addition to obesity intervention efforts, ongoing prevention initiatives are imperative to reduce the prevalence of childhood obesity.

Promoter Recognition by Extracytoplasmic Function σ Factors: Analyzing DNA and Protein Interaction Motifs

PubMed Central

Guzina, Jelena

2016-01-01

ABSTRACT Extracytoplasmic function (ECF) σ factors are the largest and the most diverse group of alternative σ factors, but their mechanisms of transcription are poorly studied. This subfamily is considered to exhibit a rigid promoter structure and an absence of mixing and matching; both −35 and −10 elements are considered necessary for initiating transcription. This paradigm, however, is based on very limited data, which bias the analysis of diverse ECF σ subgroups. Here we investigate DNA and protein recognition motifs involved in ECF σ factor transcription by a computational analysis of canonical ECF subfamily members, much less studied ECF σ subgroups, and the group outliers, obtained from recently sequenced bacteriophages. The analysis identifies an extended −10 element in promoters for phage ECF σ factors; a comparison with bacterial σ factors points to a putative 6-amino-acid motif just C-terminal of domain σ2, which is responsible for the interaction with the identified extension of the −10 element. Interestingly, a similar protein motif is found C-terminal of domain σ2 in canonical ECF σ factors, at a position where it is expected to interact with a conserved motif further upstream of the −10 element. Moreover, the phiEco32 ECF σ factor lacks a recognizable −35 element and σ4 domain, which we identify in a homologous phage, 7-11, indicating that the extended −10 element can compensate for the lack of −35 element interactions. Overall, the results reveal greater flexibility in promoter recognition by ECF σ factors than previously recognized and raise the possibility that mixing and matching also apply to this group, a notion that remains to be biochemically tested. IMPORTANCE ECF σ factors are the most numerous group of alternative σ factors but have been little studied. Their promoter recognition mechanisms are obscured by the large diversity within the ECF σ factor group and the limited similarity with the well-studied housekeeping σ factors. Here we extensively compare bacterial and bacteriophage ECF σ factors and their promoters in order to infer DNA and protein recognition motifs involved in transcription initiation. We predict a more flexible promoter structure than is recognized by the current paradigm, which assumes rigidness, and propose that ECF σ promoter elements may complement (mix and match with) each other's strengths. These results warrant the refocusing of research efforts from the well-studied housekeeping σ factors toward the physiologically highly important, but insufficiently understood, alternative σ factors. PMID:27137497

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

Lashuel, Hilal A.; Aljabari, Bayan; Sigurdsson, Einar M.

We demonstrate herein that human macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine expressed in the brain and not previously considered to be amyloidogenic, forms amyloid fibrils similar to those derived from the disease associated amyloidogenic proteins {beta}-amyloid and {alpha}-synuclein. Acid denaturing conditions were found to readily induce MIF to undergo amyloid fibril formation. MIF aggregates to form amyloid-like structures with a morphology that is highly dependent on pH. The mechanism of MIF amyloid formation was probed by electron microscopy, turbidity, Thioflavin T binding, circular dichroism spectroscopy, and analytical ultracentrifugation. The fibrillar structures formed by MIF bind Congo red andmore » exhibit the characteristic green birefringence under polarized light. These results are consistent with the notion that amyloid fibril formation is not an exclusive property of a select group of amyloidogenic proteins, and contribute to a better understanding of the factors which govern protein conformational changes and amyloid fibril formation in vivo.« less

Automatic classification of protein structures relying on similarities between alignments

PubMed Central

2012-01-01

Background Identification of protein structural cores requires isolation of sets of proteins all sharing a same subset of structural motifs. In the context of an ever growing number of available 3D protein structures, standard and automatic clustering algorithms require adaptations so as to allow for efficient identification of such sets of proteins. Results When considering a pair of 3D structures, they are stated as similar or not according to the local similarities of their matching substructures in a structural alignment. This binary relation can be represented in a graph of similarities where a node represents a 3D protein structure and an edge states that two 3D protein structures are similar. Therefore, classifying proteins into structural families can be viewed as a graph clustering task. Unfortunately, because such a graph encodes only pairwise similarity information, clustering algorithms may include in the same cluster a subset of 3D structures that do not share a common substructure. In order to overcome this drawback we first define a ternary similarity on a triple of 3D structures as a constraint to be satisfied by the graph of similarities. Such a ternary constraint takes into account similarities between pairwise alignments, so as to ensure that the three involved protein structures do have some common substructure. We propose hereunder a modification algorithm that eliminates edges from the original graph of similarities and gives a reduced graph in which no ternary constraints are violated. Our approach is then first to build a graph of similarities, then to reduce the graph according to the modification algorithm, and finally to apply to the reduced graph a standard graph clustering algorithm. Such method was used for classifying ASTRAL-40 non-redundant protein domains, identifying significant pairwise similarities with Yakusa, a program devised for rapid 3D structure alignments. Conclusions We show that filtering similarities prior to standard graph based clustering process by applying ternary similarity constraints i) improves the separation of proteins of different classes and consequently ii) improves the classification quality of standard graph based clustering algorithms according to the reference classification SCOP. PMID:22974051

How Universal Is the Big Five? Testing the Five-Factor Model of Personality Variation Among Forager–Farmers in the Bolivian Amazon

PubMed Central

Gurven, Michael; von Rueden, Christopher; Massenkoff, Maxim; Kaplan, Hillard; Vie, Marino Lero

2014-01-01

The five-factor model (FFM) of personality variation has been replicated across a range of human societies, suggesting the FFM is a human universal. However, most studies of the FFM have been restricted to literate, urban populations, which are uncharacteristic of the majority of human evolutionary history. We present the first test of the FFM in a largely illiterate, indigenous society. Tsimane forager–horticulturalist men and women of Bolivia (n = 632) completed a translation of the 44-item Big Five Inventory (Benet-Martínez & John, 1998), a widely used metric of the FFM. We failed to find robust support for the FFM, based on tests of (a) internal consistency of items expected to segregate into the Big Five factors, (b) response stability of the Big Five, (c) external validity of the Big Five with respect to observed behavior, (d) factor structure according to exploratory and confirmatory factor analysis, and (e) similarity with a U.S. target structure based on Procrustes rotation analysis. Replication of the FFM was not improved in a separate sample of Tsimane adults (n = 430), who evaluated their spouses on the Big Five Inventory. Removal of reverse-scored items that may have elicited response biases produced factors suggestive of Extraversion, Agreeableness, and Conscientiousness, but fit to the FFM remained poor. Response styles may covary with exposure to education, but we found no better fit to the FFM among Tsimane who speak Spanish or have attended school. We argue that Tsimane personality variation displays 2 principal factors that may reflect socioecological characteristics common to small-scale societies. We offer evolutionary perspectives on why the structure of personality variation may not be invariant across human societies. PMID:23245291

How universal is the Big Five? Testing the five-factor model of personality variation among forager-farmers in the Bolivian Amazon.

PubMed

Gurven, Michael; von Rueden, Christopher; Massenkoff, Maxim; Kaplan, Hillard; Lero Vie, Marino

2013-02-01

The five-factor model (FFM) of personality variation has been replicated across a range of human societies, suggesting the FFM is a human universal. However, most studies of the FFM have been restricted to literate, urban populations, which are uncharacteristic of the majority of human evolutionary history. We present the first test of the FFM in a largely illiterate, indigenous society. Tsimane forager-horticulturalist men and women of Bolivia (n = 632) completed a translation of the 44-item Big Five Inventory (Benet-Martínez & John, 1998), a widely used metric of the FFM. We failed to find robust support for the FFM, based on tests of (a) internal consistency of items expected to segregate into the Big Five factors, (b) response stability of the Big Five, (c) external validity of the Big Five with respect to observed behavior, (d) factor structure according to exploratory and confirmatory factor analysis, and (e) similarity with a U.S. target structure based on Procrustes rotation analysis. Replication of the FFM was not improved in a separate sample of Tsimane adults (n = 430), who evaluated their spouses on the Big Five Inventory. Removal of reverse-scored items that may have elicited response biases produced factors suggestive of Extraversion, Agreeableness, and Conscientiousness, but fit to the FFM remained poor. Response styles may covary with exposure to education, but we found no better fit to the FFM among Tsimane who speak Spanish or have attended school. We argue that Tsimane personality variation displays 2 principal factors that may reflect socioecological characteristics common to small-scale societies. We offer evolutionary perspectives on why the structure of personality variation may not be invariant across human societies. (c) 2013 APA, all rights reserved.

Psychometric properties of the Irish Management Standards Indicator Tool.

PubMed

Boyd, S; Kerr, R; Murray, P

2016-12-01

Work Positive is Ireland's national policy initiative to control work-related stress. Since the introduction of the UK Health and Safety Executive's Management Standards (MS) in 2004, a number of studies have been undertaken to assess the potential adaptation of the MS framework within Ireland. To investigate the dimensionality, reliability and validity of the Irish version of the MS Indicator Tool (ROI-MSIT). Between February 2011 and June 2014, we collected data from a wide range of public and private sector organizations that used the ROI-MSIT. In addition to the ROI-MSIT, respondents completed the WHO-Five Well-being Index (WHO-5). Exploratory factor analysis (EFA) was used to determine whether the ROI-MSIT maintained the structure of the UK instrument. The internal consistency of the ROI-MSIT was also assessed to determine its reliability, while its criterion-related validity was explored through correlation analysis with the WHO-5. Data were collected from 7377 participants. The factor structure of the ROI-MSIT consisted of six factors; the Demands, Control, Peer Support, Relationships and Role factors were equivalent to the original UK factors. Like the Italian version, a principal factor emerged that combined the Manager Support and Change domains. Cronbach's alpha scores ranged from 0.75 to 0.91. Finally, the ROI-MSIT's subscales and WHO-5 were positively correlated (r = 0.42-0.59, P < 0.001). The ROI-MSIT is reliable and valid, with a factor structure similar to the original UK instrument and the Italian MSIT. Further psychometric evaluation of the ROI-MSIT is recommended. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Confirmatory factor analysis of the Autonomy over Tobacco Scale (AUTOS) in adults.

PubMed

Wellman, Robert J; DiFranza, Joseph R; O'Loughlin, Jennifer

2015-11-01

The Autonomy over Tobacco Scale (AUTOS), a 12-item self-administered questionnaire, was designed to measure autonomy in three correlated lower-order symptom domains: withdrawal, psychological dependence, and cue-induced craving. The factor structure of the AUTOS remains an open question; confirmatory analyses in adolescents supported the hierarchical structure, while exploratory analyses in adolescents and adults yield single-factor solutions. Here we seek to determine whether the hypothesized hierarchical structure is valid in adult smokers. The AUTOS was administered to two independent convenience samples of adult current smokers: a calibration sample recruited in the US for online studies, and a confirmation sample drawn from the prospective Nicotine Dependence in Teens study in Montreal. We tested competing hierarchical and single-factor models using the robust weighted least-squares (WLSMV) estimation method. A single-factor model that allowed correlated error variances between theoretically related items fit well in the calibration sample (n = 434), χ(2)SB(52) = 165.71; χ(2)/df = 3.19; SRMR = 0.03; CFI = 0.96; NNFI = 0.95; RMSEA = 0.07 (95% CI: 0.06, 0.08). Reliability of the single factor was high (ωB = 0.92) and construct validity was adequate. In the confirmation sample (n = 335), a similar model fit well:χ(2)SB(53) = 126.94; χ(2)/df = 2.44; SRMR = 0.04; CFI = 0.95; NNFI = 0.93; RMSEA = 0.07 (95% CI: 0.05, 0.08). Reliability of the single factor was again high (ωB = 0.92) and construct validity was adequate. The AUTOS is unidimensional in adult smokers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Latent structures of female sexual functioning.

PubMed

Carvalho, Joana; Vieira, Armando Luís; Nobre, Pedro

2012-08-01

For the last three decades, male and female sexual responses have been conceptualized as similar, based on separated and sequential phases as proposed by the models of Masters and Johnson (1966) and Kaplan (1979) model. However, there is a growing debate around the need to conceptualize female sexual response and the classification of sexual dysfunction in women, in view of the upcoming editions of the DSM and ICD. The aim of this study was to test, using structural equation modeling, five conceptual, alternative models of female sexual function, using a sample of women with sexual difficulties and a sample of women without sexual problems. A total of 1993 Portuguese women participated in the study and completed a modified version of the Female Sexual Function Index. Findings suggested a four-factor solution as the model that best fit the data regarding women presenting sexual difficulties: (1) desire/arousal; (2) lubrication; (3) orgasm; (4) pain/vaginismus. In relation to sexually healthy women, the best model was a five-factor solution comprising of (1) desire; (2) arousal; (3) lubrication; (4) orgasm; and (5) pain/vaginismus. Discriminant validity between factors was supported, suggesting that these dimensions measure distinct phenomena. Model fit to the data significantly decreased in both samples, as models began to successively consider greater levels of overlap among phases of sexual function, towards a single-factor solution. By suggesting the overlap between pain and vaginismus, results partially support the new classification that is currently being discussed regarding DSM-5. Additionally, results on the relationship between sexual desire and arousal were inconclusive as sexually healthy women were better characterized by a five-factor model that considered the structural independence among these factors, whereas women with sexual difficulties better fit with a four-factor model merging sexual desire and subjective sexual arousal.

MD simulations of papillomavirus DNA-E2 protein complexes hints at a protein structural code for DNA deformation.

PubMed

Falconi, M; Oteri, F; Eliseo, T; Cicero, D O; Desideri, A

2008-08-01

The structural dynamics of the DNA binding domains of the human papillomavirus strain 16 and the bovine papillomavirus strain 1, complexed with their DNA targets, has been investigated by modeling, molecular dynamics simulations, and nuclear magnetic resonance analysis. The simulations underline different dynamical features of the protein scaffolds and a different mechanical interaction of the two proteins with DNA. The two protein structures, although very similar, show differences in the relative mobility of secondary structure elements. Protein structural analyses, principal component analysis, and geometrical and energetic DNA analyses indicate that the two transcription factors utilize a different strategy in DNA recognition and deformation. Results show that the protein indirect DNA readout is not only addressable to the DNA molecule flexibility but it is finely tuned by the mechanical and dynamical properties of the protein scaffold involved in the interaction.

Armours for soft bodies: how far can bioinspiration take us?

PubMed

White, Zachary W; Vernerey, Franck J

2018-05-15

The development of armour is as old as the dawn of civilization. Early man looked to natural structures to harvest or replicate for protection, leaning on millennia of evolutionary developments in natural protection. Since the advent of more modern weaponry, Armor development has seemingly been driven more by materials research than bio-inspiration. However, parallels can still be drawn between modern bullet-protective armours and natural defensive structures. Soft armour for handgun and fragmentation threats can be likened to mammalian skin, and similarly, hard armour can be compared with exoskeletons and turtle shells. Via bio-inspiration, it may be possible to develop structures previously un-researched for ballistic protection. This review will cover current modern ballistic protective structures focusing on energy dissipation and absorption methods, and their natural analogues. As all armour is a compromise between weight, flexibility and protection, the imbricated structure of scaled skin will be presented as a better balance between these factors.

Crystal structure and confirmation of the alanine:glyoxylate aminotransferase activity of the YFL030w yeast protein.

PubMed

Meyer, Philippe; Liger, Dominique; Leulliot, Nicolas; Quevillon-Cheruel, Sophie; Zhou, Cong-Zhao; Borel, Franck; Ferrer, Jean-Luc; Poupon, Anne; Janin, Joël; van Tilbeurgh, Herman

2005-12-01

We have determined the three-dimensional crystal structure of the protein encoded by the open reading frame YFL030w from Saccharomyces cerevisiae to a resolution of 2.6 A using single wavelength anomalous diffraction. YFL030w is a 385 amino-acid protein with sequence similarity to the aminotransferase family. The structure of the protein reveals a homodimer adopting the fold-type I of pyridoxal 5'-phosphate (PLP)-dependent aminotransferases. The PLP co-factor is covalently bound to the active site in the crystal structure. The protein shows close structural resemblance with the human alanine:glyoxylate aminotransferase (EC 2.6.1.44), an enzyme involved in the hereditary kidney stone disease primary hyperoxaluria type 1. In this paper we show that YFL030w codes for an alanine:glyoxylate aminotransferase, highly specific for its amino donor and acceptor substrates.

Rapid change with depth in megabenthic structure-forming communities of the Makapu'u deep-sea coral bed

NASA Astrophysics Data System (ADS)

Long, Dustin J.; Baco, Amy R.

2014-01-01

Seamounts are largely unexplored undersea mountains rising abruptly from the ocean floor, which can support an increased abundance and diversity of organisms. Deep-sea corals are important benthic structure-formers on current-swept hard substrates in these habitats. While depth is emerging as a factor structuring the fauna of seamounts on a large spatial scale, most work addressing deep-sea coral and seamount community structure has not considered the role of small-scale variation in species distributions. Video from six ROV dives over a depth range of ~320-530 m were analyzed to assess the diversity and density of benthic megafaunal invertebrates across the Makapu'u deep-sea coral bed, offshore of Oahu, Hawaii. At the same time, the physical environment along the dive track was surveyed to relate biotic patterns with abiotic variables including depth, aspect, rugosity, substrate, slope and relief to test the factors structuring community assemblages. Despite the narrow range examined, depth was found to be the strongest structuring gradient, and six unique macrobenthic communities were found, with a 93% faunal dissimilarity over the depth surveyed. Relief, rugosity and slope were also factors in the final model. Alcyonacean octocorals were the dominant macrofaunal invertebrates at all but the deepest depth zone. The commercially harvested precious coral C. secundum was the dominant species at depths 370-470 m, with a distribution that is on average deeper than similar areas. This may be artificial due to the past harvesting of this species on the shallower portion of its range. Primnoid octocorals were the most abundant octocoral family overall. This work yields new insight on the spatial ecology of seamounts, pointing out that community changes can occur over narrow depth ranges and that communities can be structured by small-scale physiography.

Recombinant factor VIIa (eptacog alfa): a review of its use in congenital hemophilia with inhibitors, acquired hemophilia, and other congenital bleeding disorders.

PubMed

Croom, Katherine F; McCormack, Paul L

2008-01-01

Recombinant factor VIIa (NovoSeven; also known as recombinant activated factor VII or eptacog alfa) is structurally similar to human plasma-derived coagulation factor VIIa, but is manufactured using DNA biotechnology. Recombinant factor VIIa interacts with thrombin-activated platelets to produce a thrombin burst leading to accelerated fibrin clot formation localized to the site of vascular injury. It is approved in many countries for use as an intravenous hemostatic agent in patients with congenital hemophilia with inhibitors, and also for acquired hemophilia, factor VII deficiency, and Glanzmann thrombasthenia in some countries. Studies have shown it to be effective and generally well tolerated when used intravenously to treat bleeding episodes or provide hemostatic cover during surgery in patients with congenital hemophilia with inhibitors, acquired hemophilia, factor VII deficiency or Glanzmann thrombasthenia. Based on available data, its efficacy in terms of patient-assessed response may be similar to that of activated prothrombin complex concentrate (aPCC), but treatment with a single 270 microg/kg dose of recombinant factor VIIa might reduce the need for rescue therapy compared with aPCC. Recombinant factor VIIa is not immunogenic in patients with hemophilia, does not produce an anamnestic response in hemophilia patients with inhibitors, and has very low thrombogenicity. It is recommended in guidelines as the treatment of choice for bleeds in patients with hemophilia B with high-responding inhibitors and for patients with factor VII deficiency, and is also a first-line therapeutic option for high-responder hemophilia A patients with inhibitors and those with acquired hemophilia. Cost data from pharmacoeconomic analyses support its use in hemophilia patients with inhibitors. Thus, recombinant factor VIIa is a valuable treatment option for patients with these rare, but potentially serious, bleeding disorders.

Confirmation of the Factor Structure and Measurement Invariance of the Children's Scale of Hostility and Aggression: Reactive/Proactive in Clinic-Referred Children With and Without Autism Spectrum Disorder.

PubMed

Farmer, Cristan A; Kaat, Aaron J; Mazurek, Micah O; Lainhart, Janet E; DeWitt, Mary Beth; Cook, Edwin H; Butter, Eric M; Aman, Michael G

2016-02-01

The measurement of aggression in its different forms (e.g., physical and verbal) and functions (e.g., impulsive and instrumental) is given little attention in subjects with developmental disabilities (DD). In this study, we confirm the factor structure of the Children's Scale for Hostility and Aggression: Reactive/Proactive (C-SHARP) and demonstrate measurement invariance (consistent performance across clinical groups) between clinic-referred groups with and without autism spectrum disorder (ASD). We also provide evidence of the construct validity of the C-SHARP. Caregivers provided C-SHARP, Child Behavior Checklist (CBCL), and Proactive/Reactive Rating Scale (PRRS) ratings for 644 children, adolescents, and young adults 2-21 years of age. Five types of measurement invariance were evaluated within a confirmatory factor analytic framework. Associations among the C-SHARP, CBCL, and PRRS were explored. The factor structure of the C-SHARP had a good fit to the data from both groups, and strict measurement invariance between ASD and non-ASD groups was demonstrated (i.e., equivalent structure, factor loadings, item intercepts and residuals, and latent variance/covariance between groups). The C-SHARP Problem Scale was more strongly associated with CBCL Externalizing than with CBCL Internalizing, supporting its construct validity. Subjects classified with the PRRS as both Reactive and Proactive had significantly higher C-SHARP Proactive Scores than those classified as Reactive only, who were rated significantly higher than those classified by the PRRS as Neither Reactive nor Proactive. A similar pattern was observed for the C-SHARP Reactive Score. This study provided evidence of the validity of the C-SHARP through confirmation of its factor structure and its relationship with more established scales. The demonstration of measurement invariance demonstrates that differences in C-SHARP factor scores were the result of differences in the construct rather than to error or unmeasured/nuisance variables. These data suggest that the C-SHARP is useful for quantifying subtypes of aggressive behavior in children, adolescents, and young adults with DD.

Experienced quality factors: qualitative evaluation approach to audiovisual quality

NASA Astrophysics Data System (ADS)

Jumisko-Pyykkö, Satu; Häkkinen, Jukka; Nyman, Göte

2007-02-01

Subjective evaluation is used to identify impairment factors of multimedia quality. The final quality is often formulated via quantitative experiments, but this approach has its constraints, as subject's quality interpretations, experiences and quality evaluation criteria are disregarded. To identify these quality evaluation factors, this study examined qualitatively the criteria participants used to evaluate audiovisual video quality. A semi-structured interview was conducted with 60 participants after a subjective audiovisual quality evaluation experiment. The assessment compared several, relatively low audio-video bitrate ratios with five different television contents on mobile device. In the analysis, methodological triangulation (grounded theory, Bayesian networks and correspondence analysis) was applied to approach the qualitative quality. The results showed that the most important evaluation criteria were the factors of visual quality, contents, factors of audio quality, usefulness - followability and audiovisual interaction. Several relations between the quality factors and the similarities between the contents were identified. As a research methodological recommendation, the focus on content and usage related factors need to be further examined to improve the quality evaluation experiments.

Metric equivalence assessment in cross-cultural research: using an example of the Center for Epidemiological Studies--Depression Scale.

PubMed

Kim, Miyong; Han, Hae-Ra; Phillips, Linda

2003-01-01

Metric equivalence is a quantitative way to assess cross-cultural equivalences of translated instruments by examining the patterns of psychometric properties based on cross-cultural data derived from both versions of the instrument. Metric equivalence checks at item and instrument levels can be used as a valuable tool to refine cross-cultural instruments. Korean and English versions of the Center for Epidemiological Studies-Depression Scale (CES-D) were administered to 154 Korean Americans and 151 Anglo Americans to illustrate approaches to assessing their metric equivalence. Inter-item and item-total correlations, Cronbach's alpha coefficients, and factor analysis were used for metric equivalence checks. The alpha coefficient for the Korean-American sample was 0.85 and 0.92 for the Anglo American sample. Although all items of the CES-D surpassed the desirable minimum of 0.30 in the Anglo American sample, four items did not meet the standard in the Korean American sample. Differences in average inter-item correlations were also noted between the two groups (0.25 for Korean Americans and 0.37 for Anglo Americans). Factor analysis identified two factors for both groups, and factor loadings showed similar patterns and congruence coefficients. Results of the item analysis procedures suggest the possibility of bias in certain items that may influence the sensitivity of the Korean version of the CES-D. These item biases also provide a possible explanation for the alpha differences. Although factor loadings showed similar patterns for the Korean and English versions of the CES-D, factorial similarity alone is not sufficient for testing the universality of the structure underlying an instrument.

7D.09: REDUCED VIT D AND ELEVATED URICEMIA INDUCE CAPILLARY RAREFACTION BEFORE MACROVASCULAR DAMAGE IN PATIENTS WITH METABOLIC SYNDROME AT THE VERY EARLY STAGES OF HYPERTENSION.

PubMed

Nazzaro, P; Schirosi, G; De Benedittis, L; Mezzapesa, D; Federico, F

2015-06-01

Reduced (L) Vit D (D) and high (H) uric acid (U) levels have been associate with increased cardiovascular risk. Aim of the study was to highlight their association with the subclinical vascular damage in untreated recently diagnosed very mild hypertensives with a similar number of metabolic syndrome factors (nATPIII). By medical visit and identification of the metabolic syndrome factors, 238 very mild hypertensives (136 ± 15/84 ± 9 mmHg), 62 controls with normal (N) D and U, 96 with LD, 40 with HU and 40 with both the conditions (LDHU) with similar metabolic assessment, underwent measures of carotid-femoral pulse wave velocity (PWV), ankle-brachial index (ABI), carotid intima-media thickness (IMT), as indices of functional and structural arterial damage, and videocapillaroscopy of the middle and distal phalangeal skin of the 2nd, 3rd and 4th finger of the non-dominant hand during baseline (CAP) and venous congestion (CVC) obtaining capillary recruitment (REC) as indices of functional and structural microcirculatory damage. Patients showed a similar hypertensive state during the medical visit and ABPM but different capillary indices.(m ± s:d.*:p<.05, **:p < .01, ***:p < .001 vs NDNU; °:p < .05, °°:p < .01, °°°:p < .001 vs LDNU;^p < .05, ^^:p < .01, ^^^:p < .001 vs NDHU).(Figure is included in full-text article.)Pearson analysis showed the association between Vit D and CVC (.440*) and REC (.335***) in LDNU and with CVC (631***) and REC (.666*) in LDHU as well as between U and CAP (-.470*) in NDHU and (-606*) in LDHU. The results suggest that, in very mild hypertensives with metabolic syndrome, reduced Vit D is associate to structural microvascular damage before the onset of structural or functional macrovascular impairment. Hyperuricemia show a lower microcirculatory damage but this is amplified in patients with both the disorders (LDHU).

Conceptualizing and Measuring Weekend versus Weekday Alcohol Use: Item Response Theory and Confirmatory Factor Analysis

PubMed Central

Handren, Lindsay; Crano, William D.

2018-01-01

Culturally, people tend to abstain from alcohol intake during the weekdays and wait to consume in greater frequency and quantity during the weekends. The current research sought to empirically justify the days representing weekday versus weekend alcohol consumption. In study 1 (N = 419), item response theory was applied to a two-parameter (difficulty and discrimination) model that evaluated the days of drinking (frequency) during the typical 7-day week. Item characteristic curves were most similar for Monday, Tuesday, and Wednesday (prototypical weekday) and for Friday and Saturday (prototypical weekend). Thursday and Sunday, however, exhibited item characteristics that bordered the properties of weekday and weekend consumption. In study 2 (N = 403), confirmatory factor analysis was applied to test six hypothesized measurement structures representing drinks per day (quantity) during the typical week. The measurement model producing the strongest fit indices was a correlated two-factor structure involving separate weekday and weekend factors that permitted Thursday and Sunday to double load on both dimensions. The proper conceptualization and accurate measurement of the days demarcating the normative boundaries of “dry” weekdays and “wet” weekends are imperative to inform research and prevention efforts targeting temporal alcohol intake patterns. PMID:27488456

Conceptualizing and Measuring Weekend versus Weekday Alcohol Use: Item Response Theory and Confirmatory Factor Analysis.

PubMed

Lac, Andrew; Handren, Lindsay; Crano, William D

2016-10-01

Culturally, people tend to abstain from alcohol intake during the weekdays and wait to consume in greater frequency and quantity during the weekends. The current research sought to empirically justify the days representing weekday versus weekend alcohol consumption. In study 1 (N = 419), item response theory was applied to a two-parameter (difficulty and discrimination) model that evaluated the days of drinking (frequency) during the typical 7-day week. Item characteristic curves were most similar for Monday, Tuesday, and Wednesday (prototypical weekday) and for Friday and Saturday (prototypical weekend). Thursday and Sunday, however, exhibited item characteristics that bordered the properties of weekday and weekend consumption. In study 2 (N = 403), confirmatory factor analysis was applied to test six hypothesized measurement structures representing drinks per day (quantity) during the typical week. The measurement model producing the strongest fit indices was a correlated two-factor structure involving separate weekday and weekend factors that permitted Thursday and Sunday to double load on both dimensions. The proper conceptualization and accurate measurement of the days demarcating the normative boundaries of "dry" weekdays and "wet" weekends are imperative to inform research and prevention efforts targeting temporal alcohol intake patterns.

Reynolds stress structures in a self-similar adverse pressure gradient turbulent boundary layer at the verge of separation.

NASA Astrophysics Data System (ADS)

Atkinson, C.; Sekimoto, A.; Jiménez, J.; Soria, J.

2018-04-01

Mean Reynolds stress profiles and instantaneous Reynolds stress structures are investigated in a self-similar adverse pressure gradient turbulent boundary layer (APG-TBL) at the verge of separation using data from direct numerical simulations. The use of a self-similar APG-TBL provides a flow domain in which the flow gradually approaches a constant non-dimensional pressure gradient, resulting in a flow in which the relative contribution of each term in the governing equations is independent of streamwise position over a domain larger than two boundary layer thickness. This allows the flow structures to undergo a development that is less dependent on the upstream flow history when compared to more rapidly decelerated boundary layers. This APG-TBL maintains an almost constant shape factor of H = 2.3 to 2.35 over a momentum thickness based Reynolds number range of Re δ 2 = 8420 to 12400. In the APG-TBL the production of turbulent kinetic energy is still mostly due to the correlation of streamwise and wall-normal fluctuations, 〈uv〉, however the contribution form the other components of the Reynolds stress tensor are no longer negligible. Statistical properties associated with the scale and location of sweeps and ejections in this APG-TBL are compared with those of a zero pressure gradient turbulent boundary layer developing from the same inlet profile, resulting in momentum thickness based range of Re δ 2 = 3400 to 3770. In the APG-TBL the peak in both the mean Reynolds stress and the production of turbulent kinetic energy move from the near wall region out to a point consistent with the displacement thickness height. This is associated with a narrower distribution of the Reynolds stress and a 1.6 times higher relative number of wall-detached negative uv structures. These structures occupy 5 times less of the boundary layer volume and show a similar reduction in their streamwise extent with respect to the boundary layer thickness. A significantly lower percentage of wall-attached structures is observed in the present case when compared with a similar investigation of a rapidly decelerating APG-TBL, suggesting that these wall-attached features could be the remanent from the lower pressure gradient domain upstream.

Importance of intrinsic properties of dense caseinate dispersions for structure formation.

PubMed

Manski, Julita M; van Riemsdijk, Lieke E; van der Goot, Atze J; Boom, Remko M

2007-11-01

Rheological measurements of dense calcium caseinate and sodium caseinate dispersions (> or =15%) provided insight into the factors determining shear-induced structure formation in caseinates. Calcium caseinate at a sufficiently high concentration (30%) was shown to form highly anisotropic structures during shearing and concurrent enzymatic cross-linking. In contrast, sodium caseinate formed isotropic structures using similar processing conditions. The main difference between the two types of caseinates is the counterion present, and as a consequence, the size of structural elements and their interactions. The rheological behavior of calcium caseinate and sodium caseinate reflected these differences, yielding non-monotonic and shear thinning flow behavior for calcium caseinate whereas sodium caseinate behaved only slightly shear thinning. It appears that the intrinsic properties of the dense caseinate dispersions, which are reflected in their rheological behavior, affect the structure formation that was found after applying shear. Therefore, rheological measurements are useful to obtain an indication of the structure formation potential of caseinate dispersions.

Regional factors rather than forest type drive the community structure of soil living oribatid mites (Acari, Oribatida).

PubMed

Erdmann, Georgia; Scheu, Stefan; Maraun, Mark

2012-06-01

Most European forests are managed by humans. However, the manner and intensity of management vary. While the effect of forest management on above-ground communities has been investigated in detail, effects on the below-ground fauna remain poorly understood. Oribatid mites are abundant microarthropods in forest soil and important decomposers in terrestrial ecosystems. Here, we investigated the effect of four forest types (i.e., managed coniferous forests; 30 and 70 years old managed beech forests; natural beech forests) on the density, diversity and community structure of oribatid mites (Acari). The study was replicated at three regions in Germany: the Swabian Alb, the Hainich and the Schorfheide. To relate changes in oribatid mite community structure to environmental factors, litter mass, pH, C and N content of litter, fine roots and C content of soil were measured. Density of oribatid mites was highest in the coniferous forests and decreased in the order 30 years old, 70 years old, and natural beech forests. Mass of the litter layer and density of oribatid mites were strongly correlated indicating that the litter layer is an important factor regulating oribatid mite densities. Diversity of oribatid mites was little affected by forest type indicating that they harbor similar numbers of niches. Species composition differed between the forest types, suggesting different types of niches. The community structure of oribatid mites differed more strongly between the three regions than between the forest types indicating that regional factors are more important than effects associated with forest type.

Multidimensional structure of employee motivation - Clustering approach

NASA Astrophysics Data System (ADS)

Gąsior, Marcin; Skowron, Łukasz; Sak-Skowron, Monika

2014-12-01

Employees' motivation along with their satisfaction with work is one of the most significant factors determining functioning and the success of an organization on the market. The purpose of this article is to demonstrate that motivation to work is a phenomenon whose nature is different among subsequent employees not only in terms of its general level, but also internal structure, and checking whether among various possible structures of motivation there is repeatability which could prove the existence of specific regularities and enabling possible classification of employees. Reasoning with regard to internal structure of motivation was conducted on the basis of the designated 14 variables expressing it, which included both internal factors (feelings) and external (actions), both positive and negative in its meaning. The conducted research consisted in segmentation of the surveyed employees using the generalized method of k-means, in order to separate groups with the same subsequent intensity profiles, so designated variables. By way of research, five various groups of employees were found. Each has a unique, different profile of motivation, at the same time, in each of them a different satisfaction level of the employed was observed. The analysis leads to a conclusion that the motivation profile itself is not completely connected with the perceived satisfaction with work. While signs of motivation positive in nature are usually stronger among satisfied employees, and the weaker - among dissatisfied ones, we cannot speak about a similar regularity when it comes to factors of negative nature. Furthermore, the presented research shows that within negative factors, larger intensification can be observed among ones of internal nature, while among these of external nature - it is smaller.

Multilineage differentiation of rhesus monkey embryonic stem cells in three-dimensional culture systems

NASA Technical Reports Server (NTRS)

Chen, Silvia S.; Revoltella, Roberto P.; Papini, Sandra; Michelini, Monica; Fitzgerald, Wendy; Zimmerberg, Joshua; Margolis, Leonid

2003-01-01

In the course of normal embryogenesis, embryonic stem (ES) cells differentiate along different lineages in the context of complex three-dimensional (3D) tissue structures. In order to study this phenomenon in vitro under controlled conditions, 3D culture systems are necessary. Here, we studied in vitro differentiation of rhesus monkey ES cells in 3D collagen matrixes (collagen gels and porous collagen sponges). Differentiation of ES cells in these 3D systems was different from that in monolayers. ES cells differentiated in collagen matrixes into neural, epithelial, and endothelial lineages. The abilities of ES cells to form various structures in two chemically similar but topologically different matrixes were different. In particular, in collagen gels ES cells formed gland-like circular structures, whereas in collagen sponges ES cells were scattered through the matrix or formed aggregates. Soluble factors produced by feeder cells or added to the culture medium facilitated ES cell differentiation into particular lineages. Coculture with fibroblasts in collagen gel facilitated ES cell differentiation into cells of a neural lineage expressing nestin, neural cell adhesion molecule, and class III beta-tubulin. In collagen sponges, keratinocytes facilitated ES cell differentiation into cells of an endothelial lineage expressing factor VIII. Exogenous granulocyte-macrophage colony-stimulating factor further enhanced endothelial differentiation. Thus, both soluble factors and the type of extracellular matrix seem to be critical in directing differentiation of ES cells and the formation of tissue-like structures. Three-dimensional culture systems are a valuable tool for studying the mechanisms of these phenomena.

Confirmatory factor analytic investigation of variance composition, gender invariance, and validity of the Male Role Norms Inventory-Adolescent-revised (MRNI-A-r).

PubMed

Levant, Ronald F; McDermott, Ryon C; Hewitt, Amber A; Alto, Kathleen M; Harris, Kyle T

2016-10-01

Confirmatory factor analysis of responses to the Male Role Norms Inventory-Adolescent-revised (MRNI-A-r) from 384 middle school students (163 boys, 221 girls) indicated that the best fit to the data was a bifactor model incorporating the hypothesized 3-factor structure while explicitly modeling an additional, general factor. Specifically, each item-level indicator loaded simultaneously on 2 factors: a general traditional masculinity ideology factor and a specific factor corresponding to 1 of the 3 hypothesized masculine norms for adolescents: Emotionally Detached Dominance, Toughness, and Avoidance of Femininity. Invariance testing across gender supported metric invariance for the general factor only. Although item loadings on the general factor were similar across boys and girls, the specific factor loadings varied substantially, with many becoming nonsignificant in the presence of the general factor for girls. A structural regression analysis predicting latent variables of the Meanings of Adolescent Masculinity Scale (MAMS), the Rosenberg Self-esteem Scale, and the Discipline, School Difficulties, and Positive Behavior Scale (DSDPBS) indicated that the general factor was a strong predictor of MAMS for both genders and DSDPBS for girls. Findings indicate that the MRNI-A-r general factor is a valid and reliable indicator of overall internalization of traditional masculinity ideology in adolescents; however, the specific factors may have different meanings for boys as compared with girls and lack validity in the presence of the general factor. These findings are consistent with a developmental perspective of gender ideology that views adolescence as a time when a differentiated cognitive schema of masculine norms is beginning to develop. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Crystal structure of a dimeric mannose-specific agglutinin from garlic: quaternary association and carbohydrate specificity.

PubMed

Chandra, N R; Ramachandraiah, G; Bachhawat, K; Dam, T K; Surolia, A; Vijayan, M

1999-01-22

A mannose-specific agglutinin, isolated from garlic bulbs, has been crystallized in the presence of a large excess of alpha-d-mannose, in space group C2 and cell dimensions, a=203.24, b=43.78, c=79.27 A, beta=112.4 degrees, with two dimers in the asymmetric unit. X-ray diffraction data were collected up to a nominal resolution of 2.4 A and the structure was solved by molecular replacement. The structure, refined to an R-factor of 22.6 % and an Rfree of 27.8 % reveals a beta-prism II fold, similar to that in the snowdrop lectin, comprising three antiparallel four-stranded beta-sheets arranged as a 12-stranded beta-barrel, with an approximate internal 3-fold symmetry. This agglutinin is, however, a dimer unlike snowdrop lectin which exists as a tetramer, despite a high degree of sequence similarity between them. A comparison of the two structures reveals a few substitutions in the garlic lectin which stabilise it into a dimer and prevent tetramer formation. Three mannose molecules have been identified on each subunit. In addition, electron density is observed for another possible mannose molecule per dimer resulting in a total of seven mannose molecules in each dimer. Although the mannose binding sites and the overall structure are similar in the subunits of snowdrop and garlic lectin, their specificities to glycoproteins such as GP120 vary considerably. These differences appear, in part, to be a direct consequence of the differences in oligomerisation, implying that variation in quaternary association may be a mode of achieving oligosaccharide specificity in bulb lectins. Copyright 1998 Academic Press.

Insights into molecular plasticity in protein complexes from Trm9-Trm112 tRNA modifying enzyme crystal structure.

PubMed

Létoquart, Juliette; van Tran, Nhan; Caroline, Vonny; Aleksandrov, Alexey; Lazar, Noureddine; van Tilbeurgh, Herman; Liger, Dominique; Graille, Marc

2015-12-15

Most of the factors involved in translation (tRNA, rRNA and proteins) are subject to post-transcriptional and post-translational modifications, which participate in the fine-tuning and tight control of ribosome and protein synthesis processes. In eukaryotes, Trm112 acts as an obligate activating platform for at least four methyltransferases (MTase) involved in the modification of 18S rRNA (Bud23), tRNA (Trm9 and Trm11) and translation termination factor eRF1 (Mtq2). Trm112 is then at a nexus between ribosome synthesis and function. Here, we present a structure-function analysis of the Trm9-Trm112 complex, which is involved in the 5-methoxycarbonylmethyluridine (mcm(5)U) modification of the tRNA anticodon wobble position and hence promotes translational fidelity. We also compare the known crystal structures of various Trm112-MTase complexes, highlighting the structural plasticity allowing Trm112 to interact through a very similar mode with its MTase partners, although those share less than 20% sequence identity. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

The Joint Damping Experiment (JDX)

NASA Technical Reports Server (NTRS)

Folkman, Steven L.; Bingham, Jeff G.; Crookston, Jess R.; Dutson, Joseph D.; Ferney, Brook D.; Ferney, Greg D.; Rowsell, Edwin A.

1997-01-01

The Joint Damping Experiment (JDX), flown on the Shuttle STS-69 Mission, is designed to measure the influence of gravity on the structural damping of a high precision three bay truss. Principal objectives are: (1) Measure vibration damping of a small-scale, pinjointed truss to determine how pin gaps give rise to gravity-dependent damping rates; (2) Evaluate the applicability of ground and low-g aircraft tests for predicting on-orbit behavior; and (3) Evaluate the ability of current nonlinear finite element codes to model the dynamic behavior of the truss. Damping of the truss was inferred from 'Twang' tests that involve plucking the truss structure and recording the decay of the oscillations. Results are summarized as follows. (1) Damping, rates can change by a factor of 3 to 8 through changing the truss orientation; (2) The addition of a few pinned joints to a truss structure can increase the damping by a factor as high as 30; (3) Damping is amplitude dependent; (4) As gravity induced preloads become large (truss long axis perpendicular to gravity vector) the damping is similar to non-pinjointed truss; (5) Impacting in joints drives higher modes in structure; (6) The torsion mode disappears if gravity induced preloads are low.

Low temperature structures of dCpG-proflavine. Conformational and hydration effects.

PubMed Central

Schneider, B; Ginell, S L; Berman, H M

1992-01-01

The structure of the complex of dCpG with proflavine was determined using x-ray data taken at -130 degrees C (low temperature) and at -2 degrees C (cold temperature) and compared with the structure of the complex determined previously at room temperature (Shieh, H. S., H. M. Berman, M. Dabrow, and S. Neidle. 1980. Nucleic Acids Res. 8:85-97). Low temperature was refined with 5,125 reflections between 8.0 and 0.93 A, Anisotropically modeled temperature factors were used for DNA/drug atoms and isotropic ones for water oxygens to R factor of 12.2% in P2(1)2(1)2; a = 32.853, b = 21.760, c = 13.296 A. Cold temperature was refined isotropically with 2,846 reflections 8.0-0.89 A to R = 15.1% in P2(1)2(1)2; a = 32.867, b = 22.356, c = 13.461 A. Both structures are very similar to the room temperature one, though some important differences were observed: one guanine sugar moiety is disordered and additional water molecules have been located that give rise to infinite polyhedral hydration networks. Images FIGURE 2 PMID:1489914

Low temperature structures of dCpG-proflavine.

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

Schneider, B.; Ginell, S. L.; Berman, H. M.

1992-12-01

The structure of the complex of dCpG with proflavine was determined using x-ray data taken at -130 degrees C (low temperature) and at -2 degrees C (cold temperature) and compared with the structure of the complex determined previously at room temperature (Shieh, H. S., H. M. Berman, M. Dabrow, and S. Neidle. 1980. Nucleic Acids Res. 8:85-97). Low temperature was refined with 5,125 reflections between 8.0 and 0.93 A, Anisotropically modeled temperature factors were used for DNA/drug atoms and isotropic ones for water oxygens to R factor of 12.2% in P2(1)2(1)2; a = 32.853, b = 21.760, c = 13.296more » A. Cold temperature was refined isotropically with 2,846 reflections 8.0-0.89 A to R = 15.1% in P2(1)2(1)2; a = 32.867, b = 22.356, c = 13.461 A. Both structures are very similar to the room temperature one, though some important differences were observed: one guanine sugar moiety is disordered and additional water molecules have been located that give rise to infinite polyhedral hydration networks.« less

Driving factors for the evolution of species-specific echolocation call design in new world free-tailed bats (molossidae).

PubMed

Jung, Kirsten; Molinari, Jesús; Kalko, Elisabeth K V

2014-01-01

Phylogeny, ecology, and sensorial constraints are thought to be the most important factors influencing echolocation call design in bats. The Molossidae is a diverse bat family with a majority of species restricted to tropical and subtropical regions. Most molossids are specialized to forage for insects in open space, and thus share similar navigational challenges. We use an unprecedented dataset on the echolocation calls of 8 genera and 18 species of New World molossids to explore how habitat, phylogenetic relatedness, body mass, and prey perception contribute to echolocation call design. Our results confirm that, with the exception of the genus Molossops, echolocation calls of these bats show a typical design for open space foraging. Two lines of evidence point to echolocation call structure of molossids reflecting phylogenetic relatedness. First, such structure is significantly more similar within than among genera. Second, except for allometric scaling, such structure is nearly the same in congeneric species. Despite contrasting body masses, 12 of 18 species call within a relatively narrow frequency range of 20 to 35 kHz, a finding that we explain by using a modeling approach whose results suggest this frequency range to be an adaptation optimizing prey perception in open space. To conclude, we argue that the high variability in echolocation call design of molossids is an advanced evolutionary trait allowing the flexible adjustment of echolocation systems to various sensorial challenges, while conserving sender identity for social communication. Unraveling evolutionary drivers for echolocation call design in bats has so far been hampered by the lack of adequate model organisms sharing a phylogenetic origin and facing similar sensorial challenges. We thus believe that knowledge of the echolocation call diversity of New World molossid bats may prove to be landmark to understand the evolution and functionality of species-specific signal design in bats.

Driving Factors for the Evolution of Species-Specific Echolocation Call Design in New World Free-Tailed Bats (Molossidae)

PubMed Central

Jung, Kirsten; Molinari, Jesús

2014-01-01

Phylogeny, ecology, and sensorial constraints are thought to be the most important factors influencing echolocation call design in bats. The Molossidae is a diverse bat family with a majority of species restricted to tropical and subtropical regions. Most molossids are specialized to forage for insects in open space, and thus share similar navigational challenges. We use an unprecedented dataset on the echolocation calls of 8 genera and 18 species of New World molossids to explore how habitat, phylogenetic relatedness, body mass, and prey perception contribute to echolocation call design. Our results confirm that, with the exception of the genus Molossops, echolocation calls of these bats show a typical design for open space foraging. Two lines of evidence point to echolocation call structure of molossids reflecting phylogenetic relatedness. First, such structure is significantly more similar within than among genera. Second, except for allometric scaling, such structure is nearly the same in congeneric species. Despite contrasting body masses, 12 of 18 species call within a relatively narrow frequency range of 20 to 35 kHz, a finding that we explain by using a modeling approach whose results suggest this frequency range to be an adaptation optimizing prey perception in open space. To conclude, we argue that the high variability in echolocation call design of molossids is an advanced evolutionary trait allowing the flexible adjustment of echolocation systems to various sensorial challenges, while conserving sender identity for social communication. Unraveling evolutionary drivers for echolocation call design in bats has so far been hampered by the lack of adequate model organisms sharing a phylogenetic origin and facing similar sensorial challenges. We thus believe that knowledge of the echolocation call diversity of New World molossid bats may prove to be landmark to understand the evolution and functionality of species-specific signal design in bats. PMID:24454833

Genetic diversity and population structure of African village dogs based on microsatellite and immunity-related molecular markers.

PubMed

Vychodilova, Leona; Necesankova, Michaela; Albrechtova, Katerina; Hlavac, Jan; Modry, David; Janova, Eva; Vyskocil, Mirko; Mihalca, Andrei D; Kennedy, Lorna J; Horin, Petr

2018-01-01

The village and street dogs represent a unique model of canine populations. In the absence of selective breeding and veterinary care, they are subject mostly to natural selection. Their analyses contribute to understanding general mechanisms governing the genetic diversity, evolution and adaptation. In this study, we analyzed the genetic diversity and population structure of African village dogs living in villages in three different geographical areas in Northern Kenya. Data obtained for neutral microsatellite molecular markers were compared with those computed for potentially non-neutral markers of candidate immunity-related genes. The neutral genetic diversity was similar to other comparable village dog populations studied so far. The overall genetic diversity in microsatellites was higher than the diversity of European pure breeds, but it was similar to the range of diversity observed in a group composed of many European breeds, indicating that the African population has maintained a large proportion of the genetic diversity of the canine species as a whole. Microsatellite marker diversity indicated that the entire population is subdivided into three genetically distinct, although closely related subpopulations. This genetical partitioning corresponded to their geographical separation and the observed gene flow well correlated with the communication patterns among the three localities. In contrast to neutral microsatellites, the genetic diversity in immunity-related candidate SNP markers was similar across all three subpopulations and to the European group. It seems that the genetic structure of this particular population of Kenyan village dogs is mostly determined by geographical and anthropogenic factors influencing the gene flow between various subpopulations rather than by biological factors, such as genetic contribution of original migrating populations and/or the pathogen-mediated selection. On the other hand, the study of oldest surviving dogs suggested a biological mechanism, i.e. a possible advantage of the overal heterozygosity marked by the the microsatellite loci analyzed.

Exploring sex differences in autistic traits: A factor analytic study of adults with autism.

PubMed

Grove, Rachel; Hoekstra, Rosa A; Wierda, Marlies; Begeer, Sander

2017-08-01

Research has highlighted potential differences in the phenotypic and clinical presentation of autism spectrum conditions across sex. Furthermore, the measures utilised to evaluate autism spectrum conditions may be biased towards the male autism phenotype. It is important to determine whether these instruments measure the autism phenotype consistently in autistic men and women. This study evaluated the factor structure of the Autism Spectrum Quotient Short Form in a large sample of autistic adults. It also systematically explored specific sex differences at the item level, to determine whether the scale assesses the autism phenotype equivalently across males and females. Factor analyses were conducted among 265 males and 285 females. A two-factor structure consisting of a social behaviour and numbers and patterns factor was consistent across groups, indicating that the latent autism phenotype is similar among both autistic men and women. Subtle differences were observed on two social behaviour item thresholds of the Autism Spectrum Quotient Short Form, with women reporting scores more in line with the scores expected in autism on these items than men. However, these differences were not substantial. This study showed that the Autism Spectrum Quotient Short Form detects autistic traits equivalently in males and females and is not biased towards the male autism phenotype.

Psychometric Properties of the Persian Version of the Padua Inventory: Washington State University Revision (PI-WSUR)

PubMed Central

Kaviani, Hosein; Esmaili, Yaghob; Ebrahimkhani, Narges; Manesh, Alireza Amin

2011-01-01

Objective The psychometric properties and factor structure of the Persian Padua Inventory Washington State University Revision (PI-WSUR), a measure of obsessive- compulsive phenomena, was examined in a non-clinical sample of 348 Iranian university students. Method The PI-WSUR was translated into Persian, and its back translation was controlled by the author inventory. A pilot study based on cultural differences was carried out on twenty students. The study subjects consisted of 348 university students, and they completed PPI, OCI-R, MOCI, BAI, STAI, BDI-II and the demographic inventory. Results The factor analysis of the PI-WSUR, exhibited eight factors similar but not identical with factor structure in previous studies. as the eight factors are as follows: contamination obsessions; washing compulsions; ordering compulsions; checking compulsions; obsessional thoughts to harm self/others; obsessional thoughts about violence; obsessional impulses to harm self/others; and obsessional impulses to steal. The result also indicated excellent internal consistency (Cronbach alpha= 0.92), Spearman split test (0.95) and test- retest (r= 0.77). We assessed the concurrent validity of the PPI in relation to the Obsessive Compulsive Inventory-Revised (OCI-R), and the Maudsley Obsessive- Compulsive Inventory (MOCI). Conclusion The Iranian version of the PI to some extend remains the sound psychometric properties of the original version. PMID:22952515

The French republican model of integration: the theory of cohesion and the practice of exclusion.

PubMed

Oberti, Marco

2008-01-01

What are the explaining factors for the wave of riots in France in November 2005? In providing some answers, this article begins by examining the practical usefulness of the French republican model of integration for social cohesion, highlighting the way its negation of other criteria, such as ethnicity, race, or religion, limit this national conception of citizenship and emphasizing these excluded factors as one of the main causes of frustration and resentment among migrant groups in France.The author compares these riots to the student movements in spring 2006 and shows some similarities as well as important differences between the explaining structural factors of these two youth-based social upheavals. One of the contributing distinctions is the experience of ethnic and racial discrimination as an important source of deep resentment. The author avoids reducing the riots simply to a clash between ethnic groups with specific ethnic interests or a class revolt. Instead, he stresses the relationship between specific social structural factors and spatial effects as the element that created the context for the riots by transforming inequalities into visible and indefensible discrimination. Several factors show that spatial aspects (in the form of segregation) are important alongside the ethnic/racial ones in explaining the riots.

Factorial invariance of pediatric patient self-reported fatigue across age and gender: a multigroup confirmatory factor analysis approach utilizing the PedsQL™ Multidimensional Fatigue Scale.

PubMed

Varni, James W; Beaujean, A Alexander; Limbers, Christine A

2013-11-01

In order to compare multidimensional fatigue research findings across age and gender subpopulations, it is important to demonstrate measurement invariance, that is, that the items from an instrument have equivalent meaning across the groups studied. This study examined the factorial invariance of the 18-item PedsQL™ Multidimensional Fatigue Scale items across age and gender and tested a bifactor model. Multigroup confirmatory factor analysis (MG-CFA) was performed specifying a three-factor model across three age groups (5-7, 8-12, and 13-18 years) and gender. MG-CFA models were proposed in order to compare the factor structure, metric, scalar, and error variance across age groups and gender. The analyses were based on 837 children and adolescents recruited from general pediatric clinics, subspecialty clinics, and hospitals in which children were being seen for well-child checks, mild acute illness, or chronic illness care. A bifactor model of the items with one general factor influencing all the items and three domain-specific factors representing the General, Sleep/Rest, and Cognitive Fatigue domains fit the data better than oblique factor models. Based on the multiple measures of model fit, configural, metric, and scalar invariance were found for almost all items across the age and gender groups, as was invariance in the factor covariances. The PedsQL™ Multidimensional Fatigue Scale demonstrated strict factorial invariance for child and adolescent self-report across gender and strong factorial invariance across age subpopulations. The findings support an equivalent three-factor structure across the age and gender groups studied. Based on these data, it can be concluded that pediatric patients across the groups interpreted the items in a similar manner regardless of their age or gender, supporting the multidimensional factor structure interpretation of the PedsQL™ Multidimensional Fatigue Scale.

Two-year Test-Retest Reliability in High School Athletes Using the Four- and Two-Factor ImPACT Composite Structures: The Effects of Learning Disorders and Headache/Migraine Treatment History.

PubMed

Brett, Benjamin L; Solomon, Gary S; Hill, Jennifer; Schatz, Philip

2018-03-01

This study examined the test-retest reliability of the four- and two-factor structures (i.e., Memory and Speed) of ImPACT over a 2-year interval across multiple groups with premorbid conditions, including those with a history of special education or learning disorders (LD; n = 114), treatment history for headache/migraine (n = 81), and a control group (n = 792). Nine hundred and eighty seven high school athletes completed baseline testing using online ImPACT across a 2-year interval. Paired-samples t-tests documented improvement from initial to follow-up assessments. Test stability was examined using Regression-based measures (RBM) and Reliable change indices (RCI). Reliability was examined using intraclass correlation coefficients (ICC). Significant improvement on all four composites were observed for the control group over a 2-year interval; whereas significant differences were observed only on Visual Motor Speed for the LD and headache/migraine treatment history groups. ICCs ranges were similar across groups and greater or comparable reliability was observed for the two-factor structure on Memory (0.67-0.73) and Speed (0.76-0.78) composites. RCIs and RBMs demonstrated stability for the four- and two-factor structures, with few cases falling outside the range of expected change within a healthy sample at the 90% and 95% CIs. Typical practices of obtaining new baselines every 2 years in the high school population can be applied to athletes with a history of special education or LD and headache/migraine treatment. The two-factor structure has potential to increase test-retest reliability. Further research regarding clinical utility is needed. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Free classification of regional dialects of American English.

PubMed

Clopper, Cynthia G; Pisoni, David B

2007-07-01

Recent studies have found that naïve listeners perform poorly in forced-choice dialect categorization tasks. However, the listeners' error patterns in these tasks reveal systematic confusions between phonologically similar dialects. In the present study, a free classification procedure was used to measure the perceptual similarity structure of regional dialect variation in the United States. In two experiments, participants listened to a set of short English sentences produced by male talkers only (Experiment 1) and by male and female talkers (Experiment 2). The listeners were instructed to group the talkers by regional dialect into as many groups as they wanted with as many talkers in each group as they wished. Multidimensional scaling analyses of the data revealed three primary dimensions of perceptual similarity (linguistic markedness, geography, and gender). In addition, a comparison of the results obtained from the free classification task to previous results using the same stimulus materials in six-alternative forced-choice categorization tasks revealed that response biases in the six-alternative task were reduced or eliminated in the free classification task. Thus, the results obtained with the free classification task in the current study provided further evidence that the underlying structure of perceptual dialect category representations reflects important linguistic and sociolinguistic factors.

Identifying gender specific risk/need areas for male and female juvenile offenders: Factor analyses with the Structured Assessment of Violence Risk in Youth (SAVRY).

PubMed

Hilterman, Ed L B; Bongers, Ilja; Nicholls, Tonia L; van Nieuwenhuizen, Chijs

2016-02-01

By constructing risk assessment tools in which the individual items are organized in the same way for male and female juvenile offenders it is assumed that these items and subscales have similar relevance across males and females. The identification of criminogenic needs that vary in relevance for 1 of the genders, could contribute to more meaningful risk assessments, especially for female juvenile offenders. In this study, exploratory factor analyses (EFA) on a construction sample of male (n = 3,130) and female (n = 466) juvenile offenders were used to aggregate the 30 items of the Structured Assessment of Violence Risk in Youth (SAVRY) into empirically based risk/need factors and explore differences between genders. The factor models were cross-validated through confirmatory factor analyses (CFA) on a validation sample of male (n = 2,076) and female (n = 357) juvenile offenders. In both the construction sample and the validation sample, 5 factors were identified: (a) Antisocial behavior; (b) Family functioning; (c) Personality traits; (d) Social support; and (e) Treatability. The male and female models were significantly different and the internal consistency of the factors was good, both in the construction sample and the validation sample. Clustering risk/need items for male and female juvenile offenders into meaningful factors may guide clinicians in the identification of gender-specific treatment interventions. PsycINFO Database Record (c) 2016 APA, all rights reserved.

Similarities in the Etiology of Alcohol Use Among Native American and Non-Native Young Women

PubMed Central

Komro, Kelli A.; Livingston, Melvin D.; Garrett, Brady A.; Boyd, Misty L.

2016-01-01

Objective: This study examined social- and individual- level factors associated with alcohol use among young women and tested whether differences exist between Native American and non-Native young women. Method: School-based surveys were conducted among 952 young women (ages 14–19) attending four high schools within the tribal jurisdictional service area of the Cherokee Nation in northeastern Oklahoma. Structural equation modeling using Mplus was used to assess the direct and indirect effects of social- and individual-level factors on subsequent alcohol use among Native and non-Native young women. Results: We found no differences in the level of risk and protective factors among Native and non-Native young women. Among Native and non-Native young women, alcohol access, parental communication, and best friends’ alcohol use had statistically significant direct and/or indirect effects on alcohol use. Indirect effects were mediated through alcohol expectancies and norms. A history of alcohol problems by an adult in the household and depression were not retained as independent risk factors in either model. Conclusions: We found more similarities than differences in level of and relations to alcohol use among social and individual risk and protective factors between Native American and non-Native young women from northeastern Oklahoma. The results provide support for universal prevention strategies, suggesting the importance of increasing perceptions that it is difficult to obtain alcohol and increasing parent–child communication. PMID:27588537

Similarities in the Etiology of Alcohol Use Among Native American and Non-Native Young Women.

PubMed

Komro, Kelli A; Livingston, Melvin D; Garrett, Brady A; Boyd, Misty L

2016-09-01

This study examined social-and individual-level factors associated with alcohol use among young women and tested whether differences exist between Native American and non-Native young women. School-based surveys were conducted among 952 young women (ages 14-19) attending four high schools within the tribal jurisdictional service area of the Cherokee Nation in northeastern Oklahoma. Structural equation modeling using Mplus was used to assess the direct and indirect effects of social-and individual-level factors on subsequent alcohol use among Native and non-Native young women. We found no differences in the level of risk and protective factors among Native and non-Native young women. Among Native and non-Native young women, alcohol access, parental communication, and best friends' alcohol use had statistically significant direct and/or indirect effects on alcohol use. Indirect effects were mediated through alcohol expectancies and norms. A history of alcohol problems by an adult in the household and depression were not retained as independent risk factors in either model. We found more similarities than differences in level of and relations to alcohol use among social and individual risk and protective factors between Native American and non-Native young women from northeastern Oklahoma. The results provide support for universal prevention strategies, suggesting the importance of increasing perceptions that it is difficult to obtain alcohol and increasing parent-child communication.

Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles.

PubMed

Duan, Meichun; Liu, Yunhui; Yu, Zhenrong; Baudry, Jacques; Li, Liangtao; Wang, Changliu; Axmacher, Jan C

2016-04-01

High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments.

Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles

PubMed Central

Duan, Meichun; Liu, Yunhui; Yu, Zhenrong; Baudry, Jacques; Li, Liangtao; Wang, Changliu; Axmacher, Jan C.

2016-01-01

High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments. PMID:27032533

Different Measures of Structural Similarity Tap Different Aspects of Visual Object Processing

PubMed Central

Gerlach, Christian

2017-01-01

The structural similarity of objects has been an important variable in explaining why some objects are easier to categorize at a superordinate level than to individuate, and also why some patients with brain injury have more difficulties in recognizing natural (structurally similar) objects than artifacts (structurally distinct objects). In spite of its merits as an explanatory variable, structural similarity is not a unitary construct, and it has been operationalized in different ways. Furthermore, even though measures of structural similarity have been successful in explaining task and category-effects, this has been based more on implication than on direct empirical demonstrations. Here, the direct influence of two different measures of structural similarity, contour overlap and within-item structural diversity, on object individuation (object decision) and superordinate categorization performance is examined. Both measures can account for performance differences across objects, but in different conditions. It is argued that this reflects differences between the measures in whether they tap: (i) global or local shape characteristics, and (ii) between- or within-category structural similarity. PMID:28861027

A multigroup confirmatory factor analysis of the Patient Health Questionnaire-9 among English- and Spanish-speaking Latinas.

PubMed

Merz, Erin L; Malcarne, Vanessa L; Roesch, Scott C; Riley, Natasha; Sadler, Georgia Robins

2011-07-01

Depression is a significant problem for ethnic minorities that remains understudied partly due to a lack of strong measures with established psychometric properties. One screening tool, the Patient Health Questionnaire-9 (PHQ-9), which was developed for use in primary care has also gained popularity in research settings. The reliability and validity of the PHQ-9 has been well established among predominantly Caucasian samples, in addition to many minority groups. However, there is little evidence regarding its utility among Hispanic Americans, a large and growing cultural group in the United States. In this study, we investigated the reliability and structural validity of the PHQ-9 in Hispanic American women. A community sample of 479 Latina women from southern California completed the PHQ-9 in their preferred language of English or Spanish. Cronbach's alphas suggested that there was good internal consistency for both the English- and Spanish-language versions. Structural validity was investigated using multigroup confirmatory factor analysis. Results support a similar one-factor structure with equivalent response patterns and variances among English- and Spanish-speaking Latinas. These results suggest that the PHQ-9 can be used with confidence in both English and Spanish versions to screen Latinas for depression.

Factor Structure Evaluation of the French Version of the Digital Natives Assessment Scale.

PubMed

Wagner, Vincent; Acier, Didier

2017-03-01

"Digital natives" concept defines young adults particularly familiar with emerging technologies such as computers, smartphones, or Internet. This notion is still controversial and so far, the primary identifying criterion was to consider their date of birth. However, literature highlighted the need to describe specific characteristics. The purpose of this research was to evaluate the factor structure of a French version of the Digital Natives Assessment Scale (DNAS). The sample of this study includes 590 participants from a 6-week massive open online course and from Web sites, electronic forums, and social networks. The DNAS was translated in French and then back-translated to English. A principal component analysis with orthogonal rotation followed by a confirmatory factorial analysis showed that a 15-item four-correlated component model provided the best fit for the data of our sample. Factor structure of this French-translated version of the DNAS was rather similar than those found in earlier studies. This study provides evidence of the DNAS robustness through cross-cultural and cross-generational validation. The French version of the DNAS appears to be appropriate as a quick and effective questionnaire to assess digital natives. More studies are needed to better define further features of this particular group.

A Multigroup Confirmatory Factor Analysis of the Patient Health Questionnaire-9 among English- and Spanish-speaking Latinas

PubMed Central

Merz, Erin L.; Malcarne, Vanessa L.; Roesch, Scott C.; Riley, Natasha; Sadler, Georgia Robins

2014-01-01

Depression is a significant problem for ethnic minorities that remains understudied partly due to a lack of strong measures with established psychometric properties. One screening tool, the Patient Health Questionnaire-9 (PHQ-9), which was developed for use in primary care has also gained popularity in research settings. The reliability and validity of the PHQ-9 has been well established among predominantly Caucasian samples, in addition to many minority groups. However, there is little evidence regarding its utility among Hispanic Americans, a large and growing cultural group in the United States. In this study, we investigated the reliability and structural validity of the PHQ-9 in Hispanic American women. A community sample of 479 Latina women from southern California completed the PHQ-9 in their preferred language of English or Spanish. Cronbach’s alphas suggested that there was good internal consistency for both the English- and Spanish-language versions. Structural validity was investigated using multigroup confirmatory factor analysis (CFA). Results support a similar one-factor structure with equivalent response patterns and variances among English- and Spanish-speaking Latinas. These results suggest that the PHQ-9 can be used with confidence in both English and Spanish versions to screen Latinas for depression. PMID:21787063

Microcavity morphology optimization

NASA Astrophysics Data System (ADS)

Ferdous, Fahmida; Demchenko, Alena A.; Vyatchanin, Sergey P.; Matsko, Andrey B.; Maleki, Lute

2014-09-01

High spectral mode density of conventional optical cavities is detrimental to the generation of broad optical frequency combs and to other linear and nonlinear applications. In this work we optimize the morphology of high-Q whispering gallery (WG) and Fabry-Perot (FP) cavities and find a set of parameters that allows treating them, essentially, as single-mode structures, thus removing limitations associated with a high density of cavity mode spectra. We show that both single-mode WGs and single-mode FP cavities have similar physical properties, in spite of their different loss mechanisms. The morphology optimization does not lead to a reduction of quality factors of modes belonging to the basic family. We study the parameter space numerically and find the region where the highest possible Q factor of the cavity modes can be realized while just having a single bound state in the cavity. The value of the Q factor is comparable with that achieved in conventional cavities. The proposed cavity structures will be beneficial for generation of octave spanning coherent frequency combs and will prevent undesirable effects of parametric instability in laser gravitational wave detectors.

Evaluation of Structural Factors Potentially Implicated in Acute Lymphoblastic Leukemia: A report of the MIGICCL.

PubMed

López-Sánchez, Dulce María; Méndez-Tenorio, Alfonso; Roacho-Pérez, Jorge Alberto; Rangel-López, Angélica

2016-10-01

Acute lymphoblastic leukemia (ALL) is the most common cancer in the pediatric population; ∼80% of the cases show some translocation. Translocations that result in ALL are due to chromosome breaks. However, the exact mechanisms that cause these breaks have not been well studied. A detailed search of the breakpoints associated with ALL reported in the NCBI database shows that some are concentrated in limited regions of the chromosome, whereas others are scattered throughout. Therefore, the objective of this study was to identify the structural factors involved in chromosomal breaks in ALL. We performed several bioinformatic studies on the sequences where chromosomal breakpoints have been reported in search of rearrangements: areas of high similarity, thermodynamic stability, composition and conformation of the DNA. Certain factors may influence chromosome breaks and are capable of predicting the propensity towards these types of events. These findings may be useful in the design of molecular techniques able to detect these changes in ALL. Copyright © 2016 IMSS. Published by Elsevier Inc. All rights reserved.

Stretching Fibroblasts Remodels Fibronectin and Alters Cancer Cell Migration

NASA Astrophysics Data System (ADS)

Ao, Mingfang; Brewer, Bryson M.; Yang, Lijie; Franco Coronel, Omar E.; Hayward, Simon W.; Webb, Donna J.; Li, Deyu

2015-02-01

Most investigations of cancer-stroma interactions have focused on biochemical signaling effects, with much less attention being paid to biophysical factors. In this study, we investigated the role of mechanical stimuli on human prostatic fibroblasts using a microfluidic platform that was adapted for our experiments and further developed for both repeatable performance among multiple assays and for compatibility with high-resolution confocal microscopy. Results show that mechanical stretching of normal tissue-associated fibroblasts (NAFs) alters the structure of secreted fibronectin. Specifically, unstretched NAFs deposit and assemble fibronectin in a random, mesh-like arrangement, while stretched NAFs produce matrix with a more organized, linearly aligned structure. Moreover, the stretched NAFs exhibited an enhanced capability for directing co-cultured cancer cell migration in a persistent manner. Furthermore, we show that stretching NAFs triggers complex biochemical signaling events through the observation of increased expression of platelet derived growth factor receptor α (PDGFRα). A comparison of these behaviors with those of cancer-associated fibroblasts (CAFs) indicates that the observed phenotypes of stretched NAFs are similar to those associated with CAFs, suggesting that mechanical stress is a critical factor in NAF activation and CAF genesis.

The Italian version of the Depression Anxiety Stress Scales-21: Factor structure and psychometric properties on community and clinical samples.

PubMed

Bottesi, Gioia; Ghisi, Marta; Altoè, Gianmarco; Conforti, Erica; Melli, Gabriele; Sica, Claudio

2015-07-01

The Depression Anxiety Stress Scales-21 (DASS-21) is the short version of a self-report measure that was originally developed to provide maximum differentiation between depressive and anxious symptoms. Despite encouraging evidence, the factor structure and other features of the DASS-21 are yet to be firmly established. A community sample of 417 participants and two clinical groups (32 depressive patients and 25 anxious patients) completed the Italian version of the DASS-21 along with several measures of psychopathology. Confirmatory factor analyses suggested that the DASS-21 is a measure of general distress plus three additional orthogonal dimensions (anxiety, depression, and stress). The internal consistency and temporal stability of the measure were good; each DASS-21 scale correlated more strongly with a measure of a similar construct, demonstrating good convergent and divergent validity. Lastly, the DASS-21 demonstrated good criterion-oriented validity. The validity of the Italian DASS-21 and its utility, both for community and clinical individuals, are supported. Copyright © 2015 Elsevier Inc. All rights reserved.

Integrating prospective longitudinal data: modeling personality and health in the Terman Life Cycle and Hawaii Longitudinal Studies.

PubMed

Kern, Margaret L; Hampson, Sarah E; Goldberg, Lewis R; Friedman, Howard S

2014-05-01

The present study used a collaborative framework to integrate 2 long-term prospective studies: the Terman Life Cycle Study and the Hawaii Personality and Health Longitudinal Study. Within a 5-factor personality-trait framework, teacher assessments of child personality were rationally and empirically aligned to establish similar factor structures across samples. Comparable items related to adult self-rated health, education, and alcohol use were harmonized, and data were pooled on harmonized items. A structural model was estimated as a multigroup analysis. Harmonized child personality factors were then used to examine markers of physiological dysfunction in the Hawaii sample and mortality risk in the Terman sample. Harmonized conscientiousness predicted less physiological dysfunction in the Hawaii sample and lower mortality risk in the Terman sample. These results illustrate how collaborative, integrative work with multiple samples offers the exciting possibility that samples from different cohorts and ages can be linked together to directly test life span theories of personality and health. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Why different countries manage death differently: a comparative analysis of modern urban societies.

PubMed

Walter, Tony

2012-03-01

The sociology of death, dying and bereavement tends to take as its implicit frame either the nation state or a homogenous modernity. Between-nation differences in the management of death and dying are either ignored or untheorized. This article seeks to identify the factors that can explain both similarities and differences in the management of death between different modern western nations. Structural factors which affect all modern nations include urbanization and the division of labour leading to the dominance of professionals, migration, rationality and bureaucracy, information technology and the risk society. How these sociologically familiar structural features are responded to, however, depends on national histories, institutions and cultures. Historically, key transitional periods to modernity, different in different nations, necessitated particular institutional responses in the management of dying and dead bodies. Culturally, key factors include individualism versus collectivism, religion, secularization, boundary regulation, and expressivism. Global flows of death practices depend significantly on subjugated nations' perceptions of colonialism, neo-colonialism and modernity, which can lead to a dominant power's death practices being either imitated or rejected. © London School of Economics and Political Science 2012.

Structural classification of small, disulfide-rich protein domains.

PubMed

Cheek, Sara; Krishna, S Sri; Grishin, Nick V

2006-05-26

Disulfide-rich domains are small protein domains whose global folds are stabilized primarily by the formation of disulfide bonds and, to a much lesser extent, by secondary structure and hydrophobic interactions. Disulfide-rich domains perform a wide variety of roles functioning as growth factors, toxins, enzyme inhibitors, hormones, pheromones, allergens, etc. These domains are commonly found both as independent (single-domain) proteins and as domains within larger polypeptides. Here, we present a comprehensive structural classification of approximately 3000 small, disulfide-rich protein domains. We find that these domains can be arranged into 41 fold groups on the basis of structural similarity. Our fold groups, which describe broader structural relationships than existing groupings of these domains, bring together representatives with previously unacknowledged similarities; 18 of the 41 fold groups include domains from several SCOP folds. Within the fold groups, the domains are assembled into families of homologs. We define 98 families of disulfide-rich domains, some of which include newly detected homologs, particularly among knottin-like domains. On the basis of this classification, we have examined cases of convergent and divergent evolution of functions performed by disulfide-rich proteins. Disulfide bonding patterns in these domains are also evaluated. Reducible disulfide bonding patterns are much less frequent, while symmetric disulfide bonding patterns are more common than expected from random considerations. Examples of variations in disulfide bonding patterns found within families and fold groups are discussed.

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

Kim, Kyung Hwan; Pathak, Harshad; Spah, Alexander

Nuclear quantum effects (NQEs) have a significant influence on the hydrogen bonds in water and aqueous solutions and have thus been the topic of extensive studies. However, the microscopic origin and the corresponding temperature dependence of NQEs have been elusive and still remain the subject of ongoing discussion. Previous x-ray scattering investigations indicate that NQEs on the structure of water exhibit significant temperature dependence. Here, by performing wide-angle x-ray scattering of H 2O and D 2O droplets at temperatures from 275 K down to 240 K, we determine the temperature dependence of NQEs on the structure of water down tomore » the deeply supercooled regime. The data reveal that the magnitude of NQEs on the structure of water is temperature independent, as the structure factor of D 2O is similar to H 2O if the temperature is shifted by a constant 5 K, valid from ambient conditions to the deeply supercooled regime. Analysis of the accelerated growth of tetrahedral structures in supercooled H 2O and D 2O also shows similar behavior with a clear 5 K shift. The results indicate a constant compensation between NQEs delocalizing the proton in the librational motion away from the bond and in the OH stretch vibrational modes along the bond. In conclusion, this is consistent with the fact that only the vibrational ground state is populated at ambient and supercooled conditions.« less

Behavioral correlates of changes in hippocampal gray matter structure during acquisition of foreign vocabulary.

PubMed

Bellander, Martin; Berggren, Rasmus; Mårtensson, Johan; Brehmer, Yvonne; Wenger, Elisabeth; Li, Tie-Qiang; Bodammer, Nils C; Shing, Yee-Lee; Werkle-Bergner, Markus; Lövdén, Martin

2016-05-01

Experience can affect human gray matter volume. The behavioral correlates of individual differences in such brain changes are not well understood. In a group of Swedish individuals studying Italian as a foreign language, we investigated associations among time spent studying, acquired vocabulary, baseline performance on memory tasks, and gray matter changes. As a way of studying episodic memory training, the language learning focused on acquiring foreign vocabulary and lasted for 10weeks. T1-weighted structural magnetic resonance imaging and cognitive testing were performed before and after the studies. Learning behavior was monitored via participants' use of a smartphone application dedicated to the study of vocabulary. A whole-brain analysis showed larger changes in gray matter structure of the right hippocampus in the experimental group (N=33) compared to an active control group (N=23). A first path analyses revealed that time spent studying rather than acquired knowledge significantly predicted change in gray matter structure. However, this association was not significant when adding performance on baseline memory measures into the model, instead only the participants' performance on a short-term memory task with highly similar distractors predicted the change. This measure may tap similar individual difference factors as those involved in gray matter plasticity of the hippocampus. Copyright © 2015 Elsevier Inc. All rights reserved.

Antibiotic Resistance Mediated by the MacB ABC Transporter Family: A Structural and Functional Perspective.

PubMed

Greene, Nicholas P; Kaplan, Elise; Crow, Allister; Koronakis, Vassilis

2018-01-01

The MacB ABC transporter forms a tripartite efflux pump with the MacA adaptor protein and TolC outer membrane exit duct to expel antibiotics and export virulence factors from Gram-negative bacteria. Here, we review recent structural and functional data on MacB and its homologs. MacB has a fold that is distinct from other structurally characterized ABC transporters and uses a unique molecular mechanism termed mechanotransmission. Unlike other bacterial ABC transporters, MacB does not transport substrates across the inner membrane in which it is based, but instead couples cytoplasmic ATP hydrolysis with transmembrane conformational changes that are used to perform work in the extra-cytoplasmic space. In the MacAB-TolC tripartite pump, mechanotransmission drives efflux of antibiotics and export of a protein toxin from the periplasmic space via the TolC exit duct. Homologous tripartite systems from pathogenic bacteria similarly export protein-like signaling molecules, virulence factors and siderophores. In addition, many MacB-like ABC transporters do not form tripartite pumps, but instead operate in diverse cellular processes including antibiotic sensing, cell division and lipoprotein trafficking.

Characterization of IXINITY® (Trenonacog Alfa), a Recombinant Factor IX with Primary Sequence Corresponding to the Threonine-148 Polymorph

PubMed Central

Monroe, Dougald M.; Jenny, Richard J.; Van Cott, Kevin E.; Saward, Laura L.

2016-01-01

The goal of these studies was to extensively characterize the first recombinant FIX therapeutic corresponding to the threonine-148 (Thr-148) polymorph, IXINITY (trenonacog alfa [coagulation factor IX (recombinant)]). Gel electrophoresis, circular dichroism, and gel filtration were used to determine purity and confirm structure. Chromatographic and mass spectrometry techniques were used to identify and quantify posttranslational modifications. Activity was assessed as the ability to activate factor X (FX) both with and without factor VIIIa (FVIIIa) and in a standard clotting assay. All results were consistent across multiple lots. Trenonacog alfa migrated as a single band on Coomassie-stained gels; activity assays were normal and showed <0.002 IU of activated factor IX (FIXa) per IU of FIX. The molecule has >97%  γ-carboxylation and underwent the appropriate structural change upon binding calcium ions. Trenonacog alfa was activated normally with factor XIa (FXIa); once activated it bound to FVIIIa and FXa. When activated to FIXa, it was inhibited efficiently by antithrombin. Glycosylation patterns were similar to plasma-derived FIX with sialic acid content consistent with the literature reports of good pharmacokinetic performance. These studies have shown that trenonacog alfa is a highly pure product with a primary sequence and posttranslational modifications consistent with the common Thr-148 polymorphism of plasma-derived FIX. PMID:26997955

Measuring pathology using the PANSS across diagnoses: Inconsistency of the positive symptom domain across schizophrenia, schizoaffective, and bipolar disorder.

PubMed

Anderson, Ariana E; Mansolf, Maxwell; Reise, Steven P; Savitz, Adam; Salvadore, Giacomo; Li, Qingqin; Bilder, Robert M

2017-12-01

Although the Positive and Negative Syndrome Scale (PANSS) was developed for use in schizophrenia (SZ), antipsychotic drug trials use the PANSS to measure symptom change also for bipolar (BP) and schizoaffective (SA) disorder, extending beyond its original indications. If the dimensions measured by the PANSS are different across diagnoses, then the same score change for the same drug condition may have different meanings depending on which group is being studied. Here, we evaluated whether the factor structure in the PANSS was consistent across schizophrenia (n = 3647), bipolar disorder (n = 858), and schizoaffective disorder (n = 592). Along with congruency coefficients, Hancock's H, and Jaccard indices, we used target rotations and statistical tests of invariance based on confirmatory factor models. We found the five symptom dimensions measured by the 30-item PANSS did not generalize well to schizoaffective and bipolar disorders. A model based on an 18-item version of the PANSS generalized better across SZ and BP groups, but significant problems remained in generalizing some of the factors to the SA sample. Schizophrenia and bipolar disorder showed greater similarity in factor structure than did schizophrenia and schizoaffective disorder. The Anxiety/Depression factor was the most consistent across disorders, while the Positive factor was the least consistent. Copyright © 2017 Elsevier B.V. All rights reserved.

Generation of crystal structures using known crystal structures as analogues

PubMed Central

Cole, Jason C.; Groom, Colin R.; Read, Murray G.; Giangreco, Ilenia; McCabe, Patrick; Reilly, Anthony M.; Shields, Gregory P.

2016-01-01

This analysis attempts to answer the question of whether similar molecules crystallize in a similar manner. An analysis of structures in the Cambridge Structural Database shows that the answer is yes – sometimes they do, particularly for single-component structures. However, one does need to define what we mean by similar in both cases. Building on this observation we then demonstrate how this correlation between shape similarity and packing similarity can be used to generate potential lattices for molecules with no known crystal structure. Simple intermolecular interaction potentials can be used to minimize these potential lattices. Finally we discuss the many limitations of this approach. PMID:27484374

Use of the Behavior Rating Inventory of Executive Function and Child Behavior Checklist in Ugandan Children with HIV or a History of Severe Malaria.

PubMed

Familiar, Itziar; Ruisenor-Escudero, Horacio; Giordani, Bruno; Bangirana, Paul; Nakasujja, Noeline; Opoka, Robert; Boivin, Michael

2015-05-01

To assess the structural overlap between the Behavior Rating Inventory of Executive Function (BRIEF) and Achenbach Child Behavior Checklist (CBCL) among children in Uganda. Caregiver ratings for the BRIEF and CBCL were obtained for 2 independent samples of school-aged children: 106 children (5-12 years old, 50% males) with a history of severe malaria and on 144 HIV-infected children (5-12 years old, 58% males) in Uganda. Exploratory factor analysis was used to evaluate the factor structure of the 8 subscales for the BRIEF and the 8 scales of the CBCL to determine correlation. Overall, children in the severe malaria group had higher (increased symptom) BRIEF and CBCL scores than those in the HIV-infected group. Three factors that provided a reasonable fit to the data and could be characterized as 3 specific domains were identified: (1) Metacognition, which consisted of the scales in the BRIEF Metacognition domain, (2) Behavioral Adjustment, which comprised of the scales in the BRIEF Behavioral Regulation domain and the Externalizing Symptoms scales in the CBCL, and (3) Emotional Adjustment, which mainly consisted of the Internalizing Symptoms scales in the CBCL. The BRIEF Behavior Regulation and CBCL Externalizing Symptoms scales, however, did overlap in terms of assessing similar behavior symptoms. These findings were consistent across the severe malaria and HIV-infected samples of children. The BRIEF and CBCL instruments offer distinct, yet complementary, assessments of behavior in clinical pediatric populations in the Ugandan context, supporting the use of these measures for similar research settings.

Use of the BRIEF and CBCL in Ugandan Children with HIV or a History of Severe Malaria

PubMed Central

Itziar, Familiar; Horacio, Ruisenor-Escudero; Bruno, Giordani; Paul, Bangirana; Noeline, Nakasujja; Robert, Opoka; Michael, Boivin

2015-01-01

Objective To assess the structural overlap between the Behavior Rating Inventory of Executive Function (BRIEF) and Achenbach Child Behavior Check List (CBCL) among children in Uganda. Methods Caregiver ratings for the BRIEF and CBCL were obtained for two independent samples of school-aged children: 106 children (5-12 years old, 50% males) with a history of severe malaria, and on 144 HIV-infected children (5-12 years old, 58% males) in Uganda. Exploratory factor analysis was used to evaluate the factor structure of the 8 sub-scales for the BRIEF and the 8 scales of the CBCL to determine correlation. Results Overall, children in the severe malaria group had higher (increased symptom) BRIEF and CBCL scores than children in the HIV-infected group. We identified 3 factors that provided a reasonable fit to the data and could be characterized as 3 specific domains: 1) Metacognition, which consisted of the scales in the BRIEF Metacognition domain; 2) Behavioral Adjustment, which was comprised of the scales in the BRIEF Behavioral Regulation domain and the Externalizing Symptoms scales in the CBCL; and 3) Emotional Adjustment, which mainly consisted of the Internalizing Symptoms scales in the CBCL. The BRIEF Behavior Regulation and CBCL Externalizing Symptoms scales, however, did overlap in terms of assessing similar behavior symptoms. These findings were consistent across the severe malaria and HIV-infected samples of children. Conclusion The BRIEF and CBCL instruments offer distinct, yet complementary, assessments of behavior in clinical pediatric populations in the Ugandan context, supporting the use of these measures for similar research settings. PMID:25738440

[The theory of multiple intelligences: a suitable neurocognitive context for the neuropsychological hypotheses on the factors and mechanisms of superiority].

PubMed

Sierra-Fitzgerald, O; Quevedo-Caicedo, J

The aim of this article is to relate two theories regarding the structure of the human mind. We suggest that the theory of multiple intelligences, a neurocognitive theory of the psychologist Howard Garnerd provides a suitable context for theoretical understanding and validation of the hypothesis of the pathology of superiority, a neuropsychological hypothesis formulated by the neuropsychologists Norman Geschwind and Albert Galaburda. Similarly, we show that, apart from being a context, the first theory enriches the second. We review the essential elements of both theories together with the arguments for them so that the reader may judge for himself. Similarly we review the factors determining intelligence; the association between neuropathology and intellectual dysfunction, general and specific, and the new directions in the understanding of human cognition. We propose to consider the first theory as a fertile ambit and broad methodological framework for investigation in neuropsychology. This simultaneously shows the relevance of including neuropsychological investigation in broader cognitive and neuropsychological theories and models.

Two distinct DNA sequences recognized by transcription factors represent enthalpy and entropy optima

PubMed Central

Yin, Yimeng; Das, Pratyush K; Jolma, Arttu; Zhu, Fangjie; Popov, Alexander; Xu, You; Nilsson, Lennart

2018-01-01

Most transcription factors (TFs) can bind to a population of sequences closely related to a single optimal site. However, some TFs can bind to two distinct sequences that represent two local optima in the Gibbs free energy of binding (ΔG). To determine the molecular mechanism behind this effect, we solved the structures of human HOXB13 and CDX2 bound to their two optimal DNA sequences, CAATAAA and TCGTAAA. Thermodynamic analyses by isothermal titration calorimetry revealed that both sites were bound with similar ΔG. However, the interaction with the CAA sequence was driven by change in enthalpy (ΔH), whereas the TCG site was bound with similar affinity due to smaller loss of entropy (ΔS). This thermodynamic mechanism that leads to at least two local optima likely affects many macromolecular interactions, as ΔG depends on two partially independent variables ΔH and ΔS according to the central equation of thermodynamics, ΔG = ΔH - TΔS. PMID:29638214

Structural characterization and chromosomal location of the mouse macrophage migration inhibitory factor gene and pseudogenes

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

Bozza, M.; Gerard, C.; Kolakowski, L.F. Jr.

1995-06-10

Macrophage migration inhibitory factor, MIF, is a cytokine released by T-lymphocytes, macrophages, and the pituitary gland that serves to integrate peripheral and central inflammatory responses. Ubiquitous expression and developmental regulation suggest that MIF may have additional roles outside of the immune system. Here we report the structure and chromosomal location of the mouse Mif gene and the partial characterization of five Mif pseudogenes. The mouse Mif gene spans less than 0.7 kb of chromosomal DNA and is composed of three exons. A comparison between the mouse and the human genes shows a similar gene structure and common regulatory elements inmore » both promoter regions. The mouse Mif gene maps to the middle region of chromosome 10, between Bcr and S100b, which have been mapped to human chromosomes 22q11 and 21q22.3, respectively. The entire sequence of two pseudogenes demonstrates the absence of introns, the presence of the 5{prime} untranslated region of the cDNA, a 3{prime} poly(A) tail, and the lack of sequence similarity with untranscribed regions of the gene. The five pseudogenes are highly homologous to the cDNA, but contain a variable number of mutations that would produce mutated or truncated MIF-like proteins. Phylogenetic analyses of MIF genes and pseudogenes indicate several independent genetic events that can account for multiple genomic integrations. Three of the Mif pseudogenes were also mapped by interspecific backcross to chromosomes 1, 9, and 17. These results suggest that Mif pseudogenes originated by retrotransposition. 46 refs., 5 figs., 1 tab.« less

Structure based alignment and clustering of proteins (STRALCP)

DOEpatents

Zemla, Adam T.; Zhou, Carol E.; Smith, Jason R.; Lam, Marisa W.

2013-06-18

Disclosed are computational methods of clustering a set of protein structures based on local and pair-wise global similarity values. Pair-wise local and global similarity values are generated based on pair-wise structural alignments for each protein in the set of protein structures. Initially, the protein structures are clustered based on pair-wise local similarity values. The protein structures are then clustered based on pair-wise global similarity values. For each given cluster both a representative structure and spans of conserved residues are identified. The representative protein structure is used to assign newly-solved protein structures to a group. The spans are used to characterize conservation and assign a "structural footprint" to the cluster.

Synthesis, physicochemical characterization and biological evaluation of chitosan sulfate as heparan sulfate mimics.

PubMed

Doncel-Pérez, Ernesto; Aranaz, Inmaculada; Bastida, Agatha; Revuelta, Julia; Camacho, Celia; Acosta, Niuris; Garrido, Leoncio; Civera, Concepción; García-Junceda, Eduardo; Heras, Angeles; Fernández-Mayoralas, Alfonso

2018-07-01

Despite the relevant biological functions of heparan sulfate (HS) glycosaminoglycans, their limited availability and the chemical heterogeneity from natural sources hamper their use for biomedical applications. Chitosan sulfates (ChS) exhibit structural similarity to HSs and may mimic their biological functions. We prepared a variety of ChS with different degree of sulfation to evaluate their ability to mimic HS in protein binding and to promote neural cell division and differentiation. The structure of the products was characterized using various spectroscopic and analytical methods. The study of their interaction with different growth factors showed that ChS bound to the proteins similarly or even better than heparin. In cell cultures, a transition effect on cell number was observed as a function of ChS concentration. Differences in promoting the expression of the differentiation markers were also found depending on the degree of sulfation and modification in the chitosan. Copyright © 2018 Elsevier Ltd. All rights reserved.

Two pheromone precursor genes are transcriptionally expressed in the homothallic ascomycete Sordaria macrospora.

PubMed

Pöggeler, S

2000-06-01

In order to analyze the involvement of pheromones in cell recognition and mating in a homothallic fungus, two putative pheromone precursor genes, named ppg1 and ppg2, were isolated from a genomic library of Sordaria macrospora. The ppg1 gene is predicted to encode a precursor pheromone that is processed by a Kex2-like protease to yield a pheromone that is structurally similar to the alpha-factor of the yeast Saccharomyces cerevisiae. The ppg2 gene encodes a 24-amino-acid polypeptide that contains a putative farnesylated and carboxy methylated C-terminal cysteine residue. The sequences of the predicted pheromones display strong structural similarity to those encoded by putative pheromones of heterothallic filamentous ascomycetes. Both genes are expressed during the life cycle of S. macrospora. This is the first description of pheromone precursor genes encoded by a homothallic fungus. Southern-hybridization experiments indicated that ppg1 and ppg2 homologues are also present in other homothallic ascomycetes.

Ridges and scarps in the equatorial belt of Mars

USGS Publications Warehouse

Lucchitta, B.K.; Klockenbrink, J.L.

1981-01-01

The morphology and distribution of ridges and scarps on Mars in the ?? 30?? latitude belt were investigated. Two distinct types of ridges were recognized. The first is long and linear, resembling mare ridges on the Moon; it occurs mostly in plains areas. The other is composed of short, anastomosing segments and occurs mostly in ancient cratered terrain and intervening plateaus. Where ridges are eroded, landscape configurations suggest that they are located along regional structures. The age of ridges is uncertain, but some are as young as the latest documented volcanic activity on Mars. The origins of ridges are probably diverse-they may result from wrinkling due to compression or from buckling due to settling over subsurface structures. The similar morphologic expressions of ridge types of various origins may be related to a similar deformation mechanism caused by two main factors: (1) most ridges are developed in thick layers of competent material and (2) ridges formed under stresses near a free surface. ?? 1981 D. Reidel Publishing Co.

Factor structure of the Edinburgh Handedness Inventory versus the Fazio Laterality Inventory in a population with established atypical handedness.

PubMed

Fazio, Rachel L; Cantor, James M

2015-01-01

The Edinburgh Handedness Inventory (EHI) has consistently remained the most used handedness inventory despite its limitations. The psychometric properties of handedness inventories, however, are increasingly important due to their use in matching groups for neuroimaging research. This study compared the performance of the EHI and the Fazio Laterality Inventory (FLI) in a population with atypical handedness. Whereas the EHI demonstrated a single-factor loading in this population, the FLI's previously demonstrated single factor dissociated into two factors: fine motor/ballistic movements and expressive/instrumental movements. This dissociation is similar to that seen when tests of cognitive constructs--which tend to load on a single factor in intact populations--dissociate when administered to populations with difficulties in the assessed domain. This pattern of performance lends further support for the use of the FLI to more accurately assess handedness. Future research in other populations with atypical laterality may illuminate additional factors of the FLI.

Frailty Index Predicts All-Cause Mortality for Middle-Aged and Older Taiwanese: Implications for Active-Aging Programs.

PubMed

Lin, Shu-Yu; Lee, Wei-Ju; Chou, Ming-Yueh; Peng, Li-Ning; Chiou, Shu-Ti; Chen, Liang-Kung

2016-01-01

Frailty Index, defined as an individual's accumulated proportion of listed health-related deficits, is a well-established metric used to assess the health status of old adults; however, it has not yet been developed in Taiwan, and its local related structure factors remain unclear. The objectives were to construct a Taiwan Frailty Index to predict mortality risk, and to explore the structure of its factors. Analytic data on 1,284 participants aged 53 and older were excerpted from the Social Environment and Biomarkers of Aging Study (2006), in Taiwan. A consensus workgroup of geriatricians selected 159 items according to the standard procedure for creating a Frailty Index. Cox proportional hazard modeling was used to explore the association between the Taiwan Frailty Index and mortality. Exploratory factor analysis was used to identify structure factors and produce a shorter version-the Taiwan Frailty Index Short-Form. During an average follow-up of 4.3 ± 0.8 years, 140 (11%) subjects died. Compared to those in the lowest Taiwan Frailty Index tertile (< 0.18), those in the uppermost tertile (> 0.23) had significantly higher risk of death (Hazard ratio: 3.2; 95% CI 1.9-5.4). Thirty-five items of five structure factors identified by exploratory factor analysis, included: physical activities, life satisfaction and financial status, health status, cognitive function, and stresses. Area under the receiver operating characteristic curves (C-statistics) of the Taiwan Frailty Index and its Short-Form were 0.80 and 0.78, respectively, with no statistically significant difference between them. Although both the Taiwan Frailty Index and Short-Form were associated with mortality, the Short-Form, which had similar accuracy in predicting mortality as the full Taiwan Frailty Index, would be more expedient in clinical practice and community settings to target frailty screening and intervention.

Exploring the Interactions of the Dietary Plant Flavonoids Fisetin and Naringenin with G-Quadruplex and Duplex DNA, Showing Contrasting Binding Behavior: Spectroscopic and Molecular Modeling Approaches.

PubMed

Bhattacharjee, Snehasish; Chakraborty, Sandipan; Sengupta, Pradeep K; Bhowmik, Sudipta

2016-09-01

Guanine-rich sequences have the propensity to fold into a four-stranded DNA structure known as a G-quadruplex (G4). G4 forming sequences are abundant in the promoter region of several oncogenes and become a key target for anticancer drug binding. Here we have studied the interactions of two structurally similar dietary plant flavonoids fisetin and naringenin with G4 as well as double stranded (duplex) DNA by using different spectroscopic and modeling techniques. Our study demonstrates the differential binding ability of the two flavonoids with G4 and duplex DNA. Fisetin more strongly interacts with parallel G4 structure than duplex DNA, whereas naringenin shows stronger binding affinity to duplex rather than G4 DNA. Molecular docking results also corroborate our spectroscopic results, and it was found that both of the ligands are stacked externally in the G4 DNA structure. C-ring planarity of the flavonoid structure appears to be a crucial factor for preferential G4 DNA recognition of flavonoids. The goal of this study is to explore the critical effects of small differences in the structure of closely similar chemical classes of such small molecules (flavonoids) which lead to the contrasting binding properties with the two different forms of DNA. The resulting insights may be expected to facilitate the designing of the highly selective G4 DNA binders based on flavonoid scaffolds.

Crystal Structure of Menin Reveals Binding Site for Mixed Lineage Leukemia (MLL) Protein

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

Murai, Marcelo J.; Chruszcz, Maksymilian; Reddy, Gireesh

2014-10-02

Menin is a tumor suppressor protein that is encoded by the MEN1 (multiple endocrine neoplasia 1) gene and controls cell growth in endocrine tissues. Importantly, menin also serves as a critical oncogenic cofactor of MLL (mixed lineage leukemia) fusion proteins in acute leukemias. Direct association of menin with MLL fusion proteins is required for MLL fusion protein-mediated leukemogenesis in vivo, and this interaction has been validated as a new potential therapeutic target for development of novel anti-leukemia agents. Here, we report the first crystal structure of menin homolog from Nematostella vectensis. Due to a very high sequence similarity, the Nematostellamore » menin is a close homolog of human menin, and these two proteins likely have very similar structures. Menin is predominantly an {alpha}-helical protein with the protein core comprising three tetratricopeptide motifs that are flanked by two {alpha}-helical bundles and covered by a {beta}-sheet motif. A very interesting feature of menin structure is the presence of a large central cavity that is highly conserved between Nematostella and human menin. By employing site-directed mutagenesis, we have demonstrated that this cavity constitutes the binding site for MLL. Our data provide a structural basis for understanding the role of menin as a tumor suppressor protein and as an oncogenic co-factor of MLL fusion proteins. It also provides essential structural information for development of inhibitors targeting the menin-MLL interaction as a novel therapeutic strategy in MLL-related leukemias.« less

Temperature-Independent Nuclear Quantum Effects on the Structure of Water

DOE PAGES

Kim, Kyung Hwan; Pathak, Harshad; Spah, Alexander; ...

2017-08-14

Nuclear quantum effects (NQEs) have a significant influence on the hydrogen bonds in water and aqueous solutions and have thus been the topic of extensive studies. However, the microscopic origin and the corresponding temperature dependence of NQEs have been elusive and still remain the subject of ongoing discussion. Previous x-ray scattering investigations indicate that NQEs on the structure of water exhibit significant temperature dependence. Here, by performing wide-angle x-ray scattering of H 2O and D 2O droplets at temperatures from 275 K down to 240 K, we determine the temperature dependence of NQEs on the structure of water down tomore » the deeply supercooled regime. The data reveal that the magnitude of NQEs on the structure of water is temperature independent, as the structure factor of D 2O is similar to H 2O if the temperature is shifted by a constant 5 K, valid from ambient conditions to the deeply supercooled regime. Analysis of the accelerated growth of tetrahedral structures in supercooled H 2O and D 2O also shows similar behavior with a clear 5 K shift. The results indicate a constant compensation between NQEs delocalizing the proton in the librational motion away from the bond and in the OH stretch vibrational modes along the bond. In conclusion, this is consistent with the fact that only the vibrational ground state is populated at ambient and supercooled conditions.« less

Facet personality and surface-level diversity as team mental model antecedents: implications for implicit coordination.

PubMed

Fisher, David M; Bell, Suzanne T; Dierdorff, Erich C; Belohlav, James A

2012-07-01

Team mental models (TMMs) have received much attention as important drivers of effective team processes and performance. Less is known about the factors that give rise to these shared cognitive structures. We examined potential antecedents of TMMs, with a specific focus on team composition variables, including various facets of personality and surface-level diversity. Further, we examined implicit coordination as an important outcome of TMMs. Results suggest that team composition in terms of the cooperation facet of agreeableness and racial diversity were significantly related to team-focused TMM similarity. TMM similarity was also positively predictive of implicit coordination, which mediated the relationship between TMM similarity and team performance. Post hoc analyses revealed a significant interaction between the trust facet of agreeableness and racial diversity in predicting TMM similarity. Results are discussed in terms of facilitating the emergence of TMMs and corresponding implications for team-related human resource practices. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

Communication: Is a coarse-grained model for water sufficient to compute Kapitza conductance on non-polar surfaces?

PubMed

Ardham, Vikram Reddy; Leroy, Frédéric

2017-10-21

Coarse-grained models have increasingly been used in large-scale particle-based simulations. However, due to their lack of degrees of freedom, it is a priori unlikely that they straightforwardly represent thermal properties with the same accuracy as their atomistic counterparts. We take a first step in addressing the impact of liquid coarse-graining on interfacial heat conduction by showing that an atomistic and a coarse-grained model of water may yield similar values of the Kapitza conductance on few-layer graphene with interactions ranging from hydrophobic to mildly hydrophilic. By design the water models employed yield similar liquid layer structures on the graphene surfaces. Moreover, they share common vibration properties close to the surfaces and thus couple with the vibrations of graphene in a similar way. These common properties explain why they yield similar Kapitza conductance values despite their bulk thermal conductivity differing by more than a factor of two.

Fold independent structural comparisons of protein-ligand binding sites for exploring functional relationships.

PubMed

Gold, Nicola D; Jackson, Richard M

2006-02-03

The rapid growth in protein structural data and the emergence of structural genomics projects have increased the need for automatic structure analysis and tools for function prediction. Small molecule recognition is critical to the function of many proteins; therefore, determination of ligand binding site similarity is important for understanding ligand interactions and may allow their functional classification. Here, we present a binding sites database (SitesBase) that given a known protein-ligand binding site allows rapid retrieval of other binding sites with similar structure independent of overall sequence or fold similarity. However, each match is also annotated with sequence similarity and fold information to aid interpretation of structure and functional similarity. Similarity in ligand binding sites can indicate common binding modes and recognition of similar molecules, allowing potential inference of function for an uncharacterised protein or providing additional evidence of common function where sequence or fold similarity is already known. Alternatively, the resource can provide valuable information for detailed studies of molecular recognition including structure-based ligand design and in understanding ligand cross-reactivity. Here, we show examples of atomic similarity between superfamily or more distant fold relatives as well as between seemingly unrelated proteins. Assignment of unclassified proteins to structural superfamiles is also undertaken and in most cases substantiates assignments made using sequence similarity. Correct assignment is also possible where sequence similarity fails to find significant matches, illustrating the potential use of binding site comparisons for newly determined proteins.

Mapping soil landscape as spatial continua: The Neural Network Approach

NASA Astrophysics Data System (ADS)

Zhu, A.-Xing

2000-03-01

A neural network approach was developed to populate a soil similarity model that was designed to represent soil landscape as spatial continua for hydroecological modeling at watersheds of mesoscale size. The approach employs multilayer feed forward neural networks. The input to the network was data on a set of soil formative environmental factors; the output from the network was a set of similarity values to a set of prescribed soil classes. The network was trained using a conjugate gradient algorithm in combination with a simulated annealing technique to learn the relationships between a set of prescribed soils and their environmental factors. Once trained, the network was used to compute for every location in an area the similarity values of the soil to the set of prescribed soil classes. The similarity values were then used to produce detailed soil spatial information. The approach also included a Geographic Information System procedure for selecting representative training and testing samples and a process of determining the network internal structure. The approach was applied to soil mapping in a watershed, the Lubrecht Experimental Forest, in western Montana. The case study showed that the soil spatial information derived using the neural network approach reveals much greater spatial detail and has a higher quality than that derived from the conventional soil map. Implications of this detailed soil spatial information for hydroecological modeling at the watershed scale are also discussed.

Factor structure and convergent validity of the Derriford Appearance Scale-24 using standard scoring versus treating ‘not applicable’ responses as missing data: a Scleroderma Patient-centered Intervention Network (SPIN) cohort study

PubMed Central

Merz, Erin L; Kwakkenbos, Linda; Carrier, Marie-Eve; Gholizadeh, Shadi; Mills, Sarah D; Fox, Rina S; Jewett, Lisa R; Williamson, Heidi; Harcourt, Diana; Assassi, Shervin; Furst, Daniel E; Gottesman, Karen; Mayes, Maureen D; Moss, Tim P; Thombs, Brett D; Malcarne, Vanessa L

2018-01-01

Objective Valid measures of appearance concern are needed in systemic sclerosis (SSc), a rare, disfiguring autoimmune disease. The Derriford Appearance Scale-24 (DAS-24) assesses appearance-related distress related to visible differences. There is uncertainty regarding its factor structure, possibly due to its scoring method. Design Cross-sectional survey. Setting Participants with SSc were recruited from 27 centres in Canada, the USA and the UK. Participants who self-identified as having visible differences were recruited from community and clinical settings in the UK. Participants Two samples were analysed (n=950 participants with SSc; n=1265 participants with visible differences). Primary and secondary outcome measures The DAS-24 factor structure was evaluated using two scoring methods. Convergent validity was evaluated with measures of social interaction anxiety, depression, fear of negative evaluation, social discomfort and dissatisfaction with appearance. Results When items marked by respondents as ‘not applicable’ were scored as 0, per standard DAS-24 scoring, a one-factor model fit poorly; when treated as missing data, the one-factor model fit well. Convergent validity analyses revealed strong correlations that were similar across scoring methods. Conclusions Treating ‘not applicable’ responses as missing improved the measurement model, but did not substantively influence practical inferences that can be drawn from DAS-24 scores. Indications of item redundancy and poorly performing items suggest that the DAS-24 could be improved and potentially shortened. PMID:29511009

Transformation and Alignment in Similarity

ERIC Educational Resources Information Center

Hodgetts, Carl J.; Hahn, Ulrike; Chater, Nick

2009-01-01

This paper contrasts two structural accounts of psychological similarity: structural alignment (SA) and Representational Distortion (RD). SA proposes that similarity is determined by how readily the structures of two objects can be brought into alignment; RD measures similarity by the complexity of the transformation that "distorts" one…

Structural Basis for Antagonism by Suramin of Heparin Binding to Vaccinia Complement Protein

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

Ganesh, Vannakambadi K.; Muthuvel, Suresh Kumar; Smith, Scott A.

2010-07-19

Suramin is a competitive inhibitor of heparin binding to many proteins, including viral envelope proteins, protein tyrosine phosphatases, and fibroblast growth factors (FGFs). It has been clinically evaluated as a potential therapeutic in treatment of cancers caused by unregulated angiogenesis, triggered by FGFs. Although it has shown clinical promise in treatment of several cancers, suramin has many undesirable side effects. There is currently no experimental structure that reveals the molecular interactions responsible for suramin inhibition of heparin binding, which could be of potential use in structure-assisted design of improved analogues of suramin. We report the structure of suramin, in complexmore » with the heparin-binding site of vaccinia virus complement control protein (VCP), which interacts with heparin in a geometrically similar manner to many FGFs. The larger than anticipated flexibility of suramin manifested in this structure, and other details of VCP-suramin interactions, might provide useful structural information for interpreting interactions of suramin with many proteins.« less

1.55 Å resolution X-ray crystal structure of Rv3902c from Mycobacterium tuberculosis

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

Reddy, Bharat G.; Moates, Derek B.; Kim, Heung-Bok

The 1.55 Å resolution X-ray crystal structure of Rv3902c from M. tuberculosis reveals a novel fold. The crystallographic structure of the Mycobacterium tuberculosis (TB) protein Rv3902c (176 residues; molecular mass of 19.8 kDa) was determined at 1.55 Å resolution. The function of Rv3902c is unknown, although several TB genes involved in bacterial pathogenesis are expressed from the operon containing the Rv3902c gene. The unique structural fold of Rv3902c contains two domains, each consisting of antiparallel β-sheets and α-helices, creating a hand-like binding motif with a small binding pocket in the palm. Structural homology searches reveal that Rv3902c has an overallmore » structure similar to that of the Salmonella virulence-factor chaperone InvB, with an r.m.s.d. for main-chain atoms of 2.3 Å along an aligned domain.« less

Measuring social desirability across language and sex: A comparison of Marlowe-Crowne Social Desirability Scale factor structures in English and Mandarin Chinese in Malaysia.

PubMed

Kurz, A Solomon; Drescher, Christopher F; Chin, Eu Gene; Johnson, Laura R

2016-06-01

Malaysia is a Southeast Asian country in which multiple languages are prominently spoken, including English and Mandarin Chinese. As psychological science continues to develop within Malaysia, there is a need for psychometrically sound instruments that measure psychological phenomena in multiple languages. For example, assessment tools for measuring social desirability could be a useful addition in psychological assessments and research studies in a Malaysian context. This study examined the psychometric performance of the English and Mandarin Chinese versions of the Marlowe-Crowne Social Desirability Scale when used in Malaysia. Two hundred and eighty-three students (64% female; 83% Chinese, 9% Indian) from two college campuses completed the Marlowe-Crowne Social Desirability Scale in their language of choice (i.e., English or Mandarin Chinese). Proposed factor structures were compared with confirmatory factor analysis, and multiple indicators-multiple causes models were used to examine measurement invariance across language and sex. Factor analyses supported a two-factor structure (i.e., Attribution and Denial) for the measure. Invariance tests revealed the scale was invariant by sex, indicating that social desirability can be interpreted similarly across sex. The scale was partially invariant by language version, with some non-invariance observed within the Denial factor. Non-invariance may be related to differences in the English and Mandarin Chinese languages, as well as cultural differences. Directions for further research include examining the measurement of social desirability in other contexts where both English and Mandarin Chinese are spoken (i.e., China) and further examining the causes of non-invariance on specific items. © 2016 The Institute of Psychology, Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Computational study of the melting-freezing transition in the quantum hard-sphere system for intermediate densities. II. Structural features.

PubMed

Sesé, Luis M; Bailey, Lorna E

2007-04-28

The structural features of the quantum hard-sphere system in the region of the fluid-face-centered-cubic-solid transition, for reduced number densities 0.45

Reliability and validity of the Fear of Intimacy Scale in China.

PubMed

Ingersoll, Travis S; Norvilitis, Jill M; Zhang, Jie; Jia, Shuhua; Tetewsky, Sheldon

2008-05-01

Participants in China (n = 343) and the United States (n = 283) completed measures to assess the reliability and validity of the Fear of Intimacy Scale (Descutner & Thelen, 1991) with a Chinese population. Internal consistency was strong in both cultures, and the factor structure was also similar between cultures, with confirmatory factor analysis (CFA) identifying three-factor models in both samples. As evidence of convergent validity, the scale was positively correlated with depression and negatively correlated with social support and self-esteem. There were gender differences between cultures, but low levels of femininity were predictive of fear of intimacy in both cultures. The influence of individualism and collectivism varied, with high levels of individualism more predictive of a fear of intimacy in China than in the United States.

Scaling behavior in the dynamics of citations to scientific journals

NASA Astrophysics Data System (ADS)

Picoli, S., Jr.; Mendes, R. S.; Malacarne, L. C.; Lenzi, E. K.

2006-08-01

We analyze a database comprising the impact factor (citations per recent items published) of scientific journals for a 13-year period (1992 2004). We find that i) the distribution of impact factors follows asymptotic power law behavior, ii) the distribution of annual logarithmic growth rates has an exponential form, and iii) the width of this distribution decays with the impact factor as a power law with exponent β simeq 0.22. The results ii) and iii) are surprising similar to those observed in the growth dynamics of organizations with complex internal structure suggesting the existence of common mechanisms underlying the dynamics of these systems. We propose a general model for such systems, an extension of the simplest model for firm growth, and compare their predictions with our empirical results.

Personality traits across countries: Support for similarities rather than differences

PubMed Central

Mac Giolla, Erik

2017-01-01

In the current climate of migration and globalization, personality characteristics of individuals from different countries have received a growing interest. Previous research has established reliable differences in personality traits across countries. The present study extends this research by examining 30 personality traits in 22 countries, based on an online survey in English with large national samples (NTotal = 130,602). The instrument used was a comprehensive, open-source measure of the Five Factor Model (FFM) (IPIP-NEO-120). We postulated that differences in personality traits between countries would be small, labeling this a Similarities Hypothesis. We found support for this in three stages. First, similarities across countries were observed for model fits for each of the five personality trait structures. Second, within-country sex differences for the five personality traits showed similar patterns across countries. Finally, the overall the contribution to personality traits from countries was less than 2%. In other words, the relationship between a country and an individual’s personality traits, however interesting, are small. We conclude that the most parsimonious explanation for the current and past findings is a cross-country personality Similarities Hypothesis. PMID:28622380

Personality traits across countries: Support for similarities rather than differences.

PubMed

Kajonius, Petri; Mac Giolla, Erik

2017-01-01

In the current climate of migration and globalization, personality characteristics of individuals from different countries have received a growing interest. Previous research has established reliable differences in personality traits across countries. The present study extends this research by examining 30 personality traits in 22 countries, based on an online survey in English with large national samples (NTotal = 130,602). The instrument used was a comprehensive, open-source measure of the Five Factor Model (FFM) (IPIP-NEO-120). We postulated that differences in personality traits between countries would be small, labeling this a Similarities Hypothesis. We found support for this in three stages. First, similarities across countries were observed for model fits for each of the five personality trait structures. Second, within-country sex differences for the five personality traits showed similar patterns across countries. Finally, the overall the contribution to personality traits from countries was less than 2%. In other words, the relationship between a country and an individual's personality traits, however interesting, are small. We conclude that the most parsimonious explanation for the current and past findings is a cross-country personality Similarities Hypothesis.

Medical weather forecast as the risk management facilities of meteopathia with population

NASA Astrophysics Data System (ADS)

Efimenko, Natalya; Chalaya, Elena; Povolotskaia, Nina; Senik, Irina; Topuriya, David

2013-04-01

Frequent cases of extreme deviations of weather conditions and anthropogenic press on the Earth atmosphere are external stressors and provoke the development of meteopathic reactions (DMR) with people suffering from dysadaptation (DA). [EGU2011-6740-3; EGU2012-6103]. The influence of weather factors on the person is multivariate which complicates the search of physiological indicators of this exposure. The results of long-term researches of meteodependence and risks development of weather-conditional pathologic reactions with people suffering from DA (1640 observed people) in various systems and human body subsystems (thermal control, cardiovascular, respiratory, vegetative and central nervous systems) were taken as a principle of calculation methodology of estimation of weather pathogenicity (EWP). This estimation is used in the system of medical weather forecast (MWF) in the resorts of Caucasian Mineral Waters and is marked as an organized structure in prevention of DMR risks. Nowadays MWF efficiency is from 78% to 95% as it depends not only on the performance of models of dynamic, synoptic, heliogeophysical forecasts, but also on the underestimation of environmental factors which often act as dominating stressors. The program of atmospheric global system monitoring and real-time forecasts doesn`t include atmospheric electricity factors, ionization factors, range and chemistry factors of aerosol particles and organic volatile plant matters in atmospheric boundary layer. New fractality researches of control mechanisms processes providing adaptation to external and internal environmental conditions with patients suffering from DA allowed us to understand the meaning of the phenomenon of structural similarity and similarity of physiological response processes to the influence of weather types with similar dominating environmental factors. Particularly, atmospheric conditions should be regarded as stressor natural factors that create deionization conditions of the surface atmosphere. The correlation of the results of the research of external respiration function, cardiovascular and central nervous systems with people suffering from DA (187 people) made in days with favorable weathers, but different in natural anion quantity in the surface atmosphere, allowed us to develop similar physiological processes at the phenomena of natural deionization. When the anions amount reduces from 1255±38 ion/cm3 to 190±13 ion/cm3, we have detected the increase of tension of vegetative index (from 458±24 to 802±44), the decrease in efficiency of neurohumoral regulation (from 0,25±0,08 to 0,06±0,02), the increase of spectrum excitability of cortical activity in the wave range of delta 0 0.4 Hz by 29%, the decrease in cortical activity in the wave range of theta 4 … 8 Hz, alpha 8 … 13 Hz beta 13 … 19 Hz, gamma 19 … 25Hz by 4-10%; the decrease in organism adaptation layer by 14% and integrated health indicator by 18%. We have also detected similar processes in cardiovascular and respiratory systems. So the problem of creation of high-quality system of medical weather forecast for the population demands the performance of interdisciplinary researches in the field of medicine, biology, meteorology and the development of DMR risk management programs at various natural and anthropogenic stressors. The studies were performed by support of the Program "Basic Sciences for Medicine" and RFBR project No.10-05-01014_a.

Structural and functional properties of the N transcriptional activation domain of thyroid transcription factor-1: similarities with the acidic activation domains.

PubMed Central

Tell, G; Perrone, L; Fabbro, D; Pellizzari, L; Pucillo, C; De Felice, M; Acquaviva, R; Formisano, S; Damante, G

1998-01-01

The thyroid transcription factor 1 (TTF-1) is a tissue-specific transcription factor involved in the development of thyroid and lung. TTF-1 contains two transcriptional activation domains (N and C domain). The primary amino acid sequence of the N domain does not show any typical characteristic of known transcriptional activation domains. In aqueous solution the N domain exists in a random-coil conformation. The increase of the milieu hydrophobicity, by the addition of trifluoroethanol, induces a considerable gain of alpha-helical structure. Acidic transcriptional activation domains are largely unstructured in solution, but, under hydrophobic conditions, folding into alpha-helices or beta-strands can be induced. Therefore our data indicate that the inducibility of alpha-helix by hydrophobic conditions is a property not restricted to acidic domains. Co-transfections experiments indicate that the acidic domain of herpes simplex virus protein VP16 (VP16) and the TTF-1 N domain are interchangeable and that a chimaeric protein, which combines VP16 linked to the DNA-binding domain of TTF-1, undergoes the same regulatory constraints that operate for the wild-type TTF-1. In addition, we demonstrate that the TTF-1 N domain possesses two typical properties of acidic activation domains: TBP (TATA-binding protein) binding and ability to activate transcription in yeast. Accordingly, the TTF-1 N domain is able to squelch the activity of the p65 acidic domain. Altogether, these structural and functional data suggest that a non-acidic transcriptional activation domain (TTF-1 N domain) activates transcription by using molecular mechanisms similar to those used by acidic domains. TTF-1 N domain and acidic domains define a family of proteins whose common property is to activate transcription through the use of mechanisms largely conserved during evolutionary development. PMID:9425125

The General Environment Fit Scale: A Factor Analysis and Test of Convergent Construct Validity

PubMed Central

Beasley, Christopher; Jason, Leonard; Miller, Steven

2014-01-01

Person-environment fit (P-E fit) was initially espoused as an important construct in the field of community psychology; however, most of the theoretical and empirical development of the construct has been conducted by industrial/organizational (I/O) psychologists. In the current study, the GEFS—a P-E fit measure was developed from I/O and business management perspectives on fit—was administered to 246 attendees of an annual convention for residents and alumni of Oxford House (OH), a network of over 1400 mutual-help recovery homes. The authors conducted confirmatory factor and convergent construct validity analyses on the GEFS. The results suggested that the theoretical factor structure of the measure adequately fit the data, suggesting that the GEFS is a valid measure of P-E fit. OH resident fit with their recovery home was related to satisfaction, but not expected tenure. Exploratory analyses revealed that the sufficient supply of resident needs by the recovery home and similarity between residents and their housemates predicted satisfaction with the recovery home, but only similarity with housemates predicted how long residents intended to stay in the OHs. PMID:22071911

Development and Validation of a Spanish Version of the Grit-S Scale

PubMed Central

Arco-Tirado, Jose L.; Fernández-Martín, Francisco D.; Hoyle, Rick H.

2018-01-01

This paper describes the development and initial validation of a Spanish version of the Short Grit (Grit-S) Scale. The Grit-S Scale was adapted and translated into Spanish using the Translation, Review, Adjudication, Pre-testing, and Documentation model and responses to a preliminary set of items from a large sample of university students (N = 1,129). The resultant measure was validated using data from a large stratified random sample of young adults (N = 1,826). Initial validation involved evaluating the internal consistency of the adapted scale and its subscales and comparing the factor structure of the adapted version to that of the original scale. The results were comparable to results from similar analyses of the English version of the scale. Although the internal consistency of the subscales was low, the internal consistency of the full scale was well-within the acceptable range. A two-factor model offered an acceptable account of the data; however, when a single correlated error involving two highly similar items was included, a single factor model fit the data very well. The results support the use of overall scores from the Spanish Grit-S Scale in future research. PMID:29467705

Did Convergent Protein Evolution Enable Phytoplasmas to Generate 'Zombie Plants'?

PubMed

Rümpler, Florian; Gramzow, Lydia; Theißen, Günter; Melzer, Rainer

2015-12-01

Phytoplasmas are pathogenic bacteria that reprogram plant development such that leaf-like structures instead of floral organs develop. Infected plants are sterile and mainly serve to propagate phytoplasmas and thus have been termed 'zombie plants'. The developmental reprogramming relies on specific interactions of the phytoplasma protein SAP54 with a small subset of MADS-domain transcription factors. Here, we propose that SAP54 folds into a structure that is similar to that of the K-domain, a protein-protein interaction domain of MADS-domain proteins. We suggest that undergoing convergent structural and sequence evolution, SAP54 evolved to mimic the K-domain. Given the high specificity of resulting developmental alterations, phytoplasmas might be used to study flower development in genetically intractable plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nonobservable nature of the nuclear shell structure: Meaning, illustrations, and consequences

NASA Astrophysics Data System (ADS)

Duguet, T.; Hergert, H.; Holt, J. D.; Somà, V.

2015-09-01

Background: The concept of single-nucleon shells constitutes a basic pillar of our understanding of nuclear structure. Effective single-particle energies (ESPEs) introduced by French [Proceedings of the International School of Physics "Enrico Fermi," Course XXXVI, Varenna 1965, edited by C. Bloch (Academic Press, New York, 1966)] and Baranger [Nucl. Phys. A 149, 225 (1970), 10.1016/0375-9474(70)90692-5] represent the most appropriate tool to relate many-body observables to a single-nucleon shell structure. As briefly discussed in Duguet and Hagen [Phys. Rev. C 85, 034330 (2012), 10.1103/PhysRevC.85.034330], the dependence of ESPEs on one-nucleon transfer probability matrices makes them purely theoretical quantities that "run" with the nonobservable resolution scale λ employed in the calculation. Purpose: Given that ESPEs provide a way to interpret the many-body problem in terms of simpler theoretical ingredients, the goal is to specify the terms, i.e., the exact sense and conditions, in which this interpretation can be conducted meaningfully. Methods: While the nuclear shell structure is both scale and scheme dependent, the present study focuses on the former. A detailed discussion is provided to illustrate the scale (in)dependence of observables and nonobservables and the reasons why ESPEs, i.e., the shell structure, belong to the latter category. State-of-the-art multireference in-medium similarity renormalization group and self-consistent Gorkov Green's function many-body calculations are employed to corroborate the formal analysis. This is done by comparing the behavior of several observables and of nonobservable ESPEs (and spectroscopic factors) under (quasi) unitary similarity renormalization group transformations of the Hamiltonian parametrized by the resolution scale λ . Results: The formal proofs are confirmed by the results of ab initio many-body calculations in their current stage of implementation. In practice, the unitarity of the similarity transformations is broken owing to the omission of induced many-body interactions beyond three-body operators and to the nonexact treatment of the many-body Schrödinger equation. The impact of this breaking is first characterized by quantifying the artificial running of observables over a (necessarily) finite interval of λ values. Then the genuine running of ESPEs is characterized and shown to be convincingly larger than the one of observables (which would be zero in an exact calculation). Conclusions: The nonobservable nature of the nuclear shell structure, i.e., the fact that it constitutes an intrinsically theoretical object with no counterpart in the empirical world, must be recognized and assimilated. Indeed, the shell structure cannot be determined uniquely from experimental data and cannot be talked about in an absolute sense as it depends on the nonobservable resolution scale employed in the theoretical calculation. It is only at the price of fixing arbitrarily (but conveniently) such a scale that one can establish correlations between observables and the shell structure. To some extent, fixing the resolution scale provides ESPEs (and spectroscopic factors) with a quasi-observable character. Eventually, practitioners can refer to nuclear shells and spectroscopic factors in their analyses of nuclear phenomena if, and only if, they use consistent structure and reaction theoretical schemes based on a fixed resolution scale they have agreed on prior to performing their analysis and comparisons.

Fibrin structural and diffusional analysis suggests that fibers are permeable to solute transport.

PubMed

Leonidakis, Kimon Alexandros; Bhattacharya, Pinaki; Patterson, Jennifer; Vos, Bart E; Koenderink, Gijsje H; Vermant, Jan; Lambrechts, Dennis; Roeffaers, Maarten; Van Oosterwyck, Hans

2017-01-01

Fibrin hydrogels are promising carrier materials in tissue engineering. They are biocompatible and easy to prepare, they can bind growth factors and they can be prepared from a patient's own blood. While fibrin structure and mechanics have been extensively studied, not much is known about the relation between structure and diffusivity of solutes within the network. This is particularly relevant for solutes with a size similar to that of growth factors. A novel methodological approach has been used in this study to retrieve quantitative structural characteristics of fibrin hydrogels, by combining two complementary techniques, namely confocal fluorescence microscopy with a fiber extraction algorithm and turbidity measurements. Bulk rheological measurements were conducted to determine the impact of fibrin hydrogel structure on mechanical properties. From these measurements it can be concluded that variations in the fibrin hydrogel structure have a large impact on the rheological response of the hydrogels (up to two orders of magnitude difference in storage modulus) but only a moderate influence on the diffusivity of dextran solutes (up to 25% difference). By analyzing the diffusivity measurements by means of the Ogston diffusion model we further provide evidence that individual fibrin fibers can be semi-permeable to solute transport, depending on the average distance between individual protofibrils. This can be important for reducing mass transport limitations, for modulating fibrinolysis and for growth factor binding, which are all relevant for tissue engineering. Fibrin is a natural biopolymer that has drawn much interest as a biomimetic carrier in tissue engineering applications. We hereby use a novel combined approach for the structural characterization of fibrin networks based on optical microscopy and light scattering methods that can also be applied to other fibrillar hydrogels, like collagen. Furthermore, our findings on the relation between solute transport and fibrin structural properties can lead to the optimized design of fibrin hydrogel constructs for controlled release applications. Finally, we provide new evidence for the fact that fibrin fibers may be permeable for solutes with a molecular weight comparable to that of growth factors. This finding may open new avenues for tailoring mass transport properties of fibrin carriers. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.