Adolescent Executive Dysfunction in Daily Life: Relationships to Risks, Brain Structure and Substance Use

Directory of Open Access Journals (Sweden)

Duncan B. Clark

2017-11-01

Full Text Available During adolescence, problems reflecting cognitive, behavioral and affective dysregulation, such as inattention and emotional dyscontrol, have been observed to be associated with substance use disorder (SUD risks and outcomes. Prior studies have typically been with small samples, and have typically not included comprehensive measurement of executive dysfunction domains. The relationships of executive dysfunction in daily life with performance based testing of cognitive skills and structural brain characteristics, thought to be the basis for executive functioning, have not been definitively determined. The aims of this study were to determine the relationships between executive dysfunction in daily life, measured by the Behavior Rating Inventory of Executive Function (BRIEF, cognitive skills and structural brain characteristics, and SUD risks, including a global SUD risk indicator, sleep quality, and risky alcohol and cannabis use. In addition to bivariate relationships, multivariate models were tested. The subjects (n = 817; ages 12 through 21 were participants in the National Consortium on Alcohol and Neurodevelopment in Adolescence (NCANDA study. The results indicated that executive dysfunction was significantly related to SUD risks, poor sleep quality, risky alcohol use and cannabis use, and was not significantly related to cognitive skills or structural brain characteristics. In multivariate models, the relationship between poor sleep quality and risky substance use was mediated by executive dysfunction. While these cross-sectional relationships need to be further examined in longitudinal analyses, the results suggest that poor sleep quality and executive dysfunction may be viable preventive intervention targets to reduce adolescent substance use.

The Relationship between Corporate Performance and Ownership Structure: Evidence from Turkey

Directory of Open Access Journals (Sweden)

Hicabi Ersoy

2015-11-01

Full Text Available This study investigates the effects of ownership structure on the performance of the listed companies in Borsa Istanbul Stock Exchange 30 Firms (BIST 30. The main hypothesis of our study is that there is a significant relationship between companies' performances and their ownership structures.The statistical population includes 19 non-financial companies in the period of years between 2008 and 2013. The results show that the concentration of the large shares of companies one or a few share holders has a negative effect on related firm’s performance.

Investigating the Structure-Activity Relationship of the Insecticidal Natural Product Rocaglamide.

Science.gov (United States)

Hall, Roger G; Bruce, Ian; Cooke, Nigel G; Diorazio, Louis J; Cederbaum, Fredrik; Dobler, Markus R; Irving, Ed

2017-12-01

The natural product Rocaglamide (1), isolated from the tree Aglaia elliptifolia, is a compelling but also challenging lead structure for crop protection. In laboratory assays, the natural product shows highly interesting insecticidal activity against chewing pests and beetles, but also phytotoxicity on some crop plants. Multi-step syntheses with control of stereochemistry were required to probe the structure-activity relationship (SAR), and seek simplified analogues. After a significant research effort, just two areas of the molecule were identified which allow modification whilst maintaining activity, as will be highlighted in this paper.

Rare-earth transition-metal intermetallics: Structure-bonding-property relationships

Energy Technology Data Exchange (ETDEWEB)

Han, M. K. [Iowa State Univ., Ames, IA (United States)

2006-01-01

The explorations of rare-earth, transition metal intermetallics have resulted in the synthesis and characterization, and electronic structure investigation, as well as understanding the structure-bonding property relationships. The work has presented the following results: (1) Understanding the relationship between compositions and properties in LaFe_13-xSi_x system: A detailed structural and theoretical investigation provided the understanding of the role of a third element on stabilizing the structure and controlling the transformation of cubic NaZn{sub 13}-type structures to the tetragonal derivative, as well as the relationship between the structures and properties. (2) Synthesis of new ternary rare-earth iron silicides Re_2-xFe₄Si_14-y and proposed superstructure: This compound offers complex structural challenges such as fractional occupancies and their ordering in superstructure. (3) Electronic structure calculation of FeSi₂: This shows that the metal-semiconductor phase transition depends on the structure. The mechanism of band gap opening is described in terms of bonding and structural distortion. This result shows that the electronic structure calculations are an essential tool for understanding the relationship between structure and chemical bonding in these compounds. (4) Synthesis of new ternary rare-earth Zinc aluminides Tb₃Zn_3.6Al_7.4: Partially ordered structure of Tb₃Zn_3.6Al_7.4 compound provides new insights into the formation, composition and structure of rare-earth transition-metal intermetallics. Electronic structure calculations attribute the observed composition to optimizing metal-metal bonding in the electronegative (Zn, Al) framework, while the specific ordering is strongly influenced by specific orbital interactions. (5) Synthesis of new structure type of Zn₃₉(Cr_xAl_1-x)₈₁

Rare-Earth Transition-Metal Intermetallics: Structure-bonding-Property Relationships

Energy Technology Data Exchange (ETDEWEB)

Han, Mi-Kyung [Iowa State Univ., Ames, IA (United States)

2006-01-01

Our explorations of rare-earth, transition metal intermetallics have resulted in the synthesis and characterization, and electronic structure investigation, as well as understanding the structure-bonding-property relationships. Our work has presented the following results: (1) Understanding the relationship between compositions and properties in LaFe_13-xSi_x system: A detailed structural and theoretical investigation provided the understanding of the role of a third element on stabilizing the structure and controlling the transformation of cubic NaZn₁₃-type structures to the tetragonal derivative, as well as the relationship between the structures and properties. (2) Synthesis of new ternary rare-earth iron silicides RE_2-xFe₄Si_14-y and proposed superstructure: This compound offers complex structural challenges such as fractional occupancies and their ordering in superstructure. (3) Electronic structure calculation of FeSi₂: This shows that the metal-semiconductor phase transition depends on the structure. The mechanism of band gap opening is described in terms of bonding and structural distortion. This result shows that the electronic structure calculations are an essential tool for understanding the relationship between structure and chemical bonding in these compounds. (4) Synthesis of new ternary rare-earth Zinc aluminides Tb₃Zn_3.6Al_7.4: Partially ordered structure of Tb_3.6Zn_13-xAl_7.4 compound provides new insights into the formation, composition and structure of rare-earth transition-metal intermetallics. Electronic structure calculations attribute the observed composition to optimizing metal-metal bonding in the electronegative (Zn, Al) framework, while the specific ordering is strongly influenced by specific orbital interactions. (5) Synthesis of new structure type of Zn₃₉(Cr_xAl_1-x

A study on the relationship between organizational structure and organizational agility: A case study of insurance firm

Directory of Open Access Journals (Sweden)

Javad Sadeghi

2012-09-01

Full Text Available The primary aim of this survey is to study the relationship between organizational structure and organizational agility in an insurance company in Iran. The statistical population includes 300 employees and managers of the proposed insurance company across in Tehran province, Iran and a sample of 73 people are selected, randomly for the survey. Questionnaire is used as a major tool of data collection. Validity of the questionnaire is confirmed through content validity by professors and experts. Reliability of the questionnaire was calculated using Cronbach alpha. SPSS software is used for data analysis. Research findings illustrate there is a significant relationship between organizational agility and two dimensions of organizational structure, i.e. formalization and centralization. No significant relationship was observed between complexity and organizational agility.

Structure-activity relationship of surfactant for preparing DMFC anodic catalyst

International Nuclear Information System (INIS)

Su Yi; Xue Xinzhong; Xu Weilin; Liu Changpeng; Xing Wei; Zhou Xiaochun; Tian Tian; Lu Tianhong

2006-01-01

Three kinds of surfactants as stabilizer were applied to the preparation of electrocatalysts for direct methanol fuel cell (DMFC). The catalysts have been characterized by examining their catalytic activities, morphologies and particle sizes by means of cyclic voltammetry, chronoamperometry, X-ray diffraction and transmission electron microscopy (TEM). It is found that the surfactants with different structures have a significantly influence on the catalyst shape and activity. The catalysts prepared with non-ionic surfactants as the stabilizer show higher activity for direct oxidation of methanol. The structure-activity relationship (SAR) analysis has been explored and the effect of hydrophile-lipophile balance (HLB value) has also been discussed

The NMR structure of human obestatin in membrane-like environments: insights into the structure-bioactivity relationship of obestatin.

Science.gov (United States)

Alén, Begoña O; Nieto, Lidia; Gurriarán-Rodríguez, Uxía; Mosteiro, Carlos S; Álvarez-Pérez, Juan C; Otero-Alén, María; Camiña, Jesús P; Gallego, Rosalía; García-Caballero, Tomás; Martín-Pastor, Manuel; Casanueva, Felipe F; Jiménez-Barbero, Jesús; Pazos, Yolanda

2012-01-01

The quest for therapeutic applications of obestatin involves, as a first step, the determination of its 3D solution structure and the relationship between this structure and the biological activity of obestatin. On this basis, we have employed a combination of circular dichroism (CD), nuclear magnetic resonance (NMR) spectroscopy, and modeling techniques to determine the solution structure of human obestatin (1). Other analogues, including human non-amidated obestatin (2) and the fragment peptides (6-23)-obestatin (3), (11-23)-obestatin (4), and (16-23)-obestatin (5) have also been scrutinized. These studies have been performed in a micellar environment to mimic the cell membrane (sodium dodecyl sulfate, SDS). Furthermore, structural-activity relationship studies have been performed by assessing the in vitro proliferative capabilities of these peptides in the human retinal pigmented epithelial cell line ARPE-19 (ERK1/2 and Akt phosphorylation, Ki67 expression, and cellular proliferation). Our findings emphasize the importance of both the primary structure (composition and size) and particular segments of the obestatin molecule that posses significant α-helical characteristics. Additionally, details of a species-specific role for obestatin have also been hypothesized by comparing human and mouse obestatins (1 and 6, respectively) at both the structural and bioactivity levels.

The NMR structure of human obestatin in membrane-like environments: insights into the structure-bioactivity relationship of obestatin.

Directory of Open Access Journals (Sweden)

Begoña O Alén

Full Text Available The quest for therapeutic applications of obestatin involves, as a first step, the determination of its 3D solution structure and the relationship between this structure and the biological activity of obestatin. On this basis, we have employed a combination of circular dichroism (CD, nuclear magnetic resonance (NMR spectroscopy, and modeling techniques to determine the solution structure of human obestatin (1. Other analogues, including human non-amidated obestatin (2 and the fragment peptides (6-23-obestatin (3, (11-23-obestatin (4, and (16-23-obestatin (5 have also been scrutinized. These studies have been performed in a micellar environment to mimic the cell membrane (sodium dodecyl sulfate, SDS. Furthermore, structural-activity relationship studies have been performed by assessing the in vitro proliferative capabilities of these peptides in the human retinal pigmented epithelial cell line ARPE-19 (ERK1/2 and Akt phosphorylation, Ki67 expression, and cellular proliferation. Our findings emphasize the importance of both the primary structure (composition and size and particular segments of the obestatin molecule that posses significant α-helical characteristics. Additionally, details of a species-specific role for obestatin have also been hypothesized by comparing human and mouse obestatins (1 and 6, respectively at both the structural and bioactivity levels.

Quantitative structure-activity relationship (QSAR) models for polycyclic aromatic hydrocarbons (PAHs) dissipation in rhizosphere based on molecular structure and effect size

International Nuclear Information System (INIS)

Ma Bin; Chen Huaihai; Xu Minmin; Hayat, Tahir; He Yan; Xu Jianming

2010-01-01

Rhizoremediation is a significant form of bioremediation for polycyclic aromatic hydrocarbons (PAHs). This study examined the role of molecular structure in determining the rhizosphere effect on PAHs dissipation. Effect size in meta-analysis was employed as activity dataset for building quantitative structure-activity relationship (QSAR) models and accumulative effect sizes of 16 PAHs were used for validation of these models. Based on the genetic algorithm combined with partial least square regression, models for comprehensive dataset, Poaceae dataset, and Fabaceae dataset were built. The results showed that information indices, calculated as information content of molecules based on the calculation of equivalence classes from the molecular graph, were the most important molecular structural indices for QSAR models of rhizosphere effect on PAHs dissipation. The QSAR model, based on the molecular structure indices and effect size, has potential to be used in studying and predicting the rhizosphere effect of PAHs dissipation. - Effect size based on meta-analysis was used for building PAHs dissipation quantitative structure-activity relationship (QSAR) models.

Quantitative structure-activity relationship (QSAR) models for polycyclic aromatic hydrocarbons (PAHs) dissipation in rhizosphere based on molecular structure and effect size

Energy Technology Data Exchange (ETDEWEB)

Ma Bin; Chen Huaihai; Xu Minmin; Hayat, Tahir [Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Natural Resource Sciences, Zhejiang University, Hangzhou 310029 (China); He Yan, E-mail: yhe2006@zju.edu.c [Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Natural Resource Sciences, Zhejiang University, Hangzhou 310029 (China); Xu Jianming, E-mail: jmxu@zju.edu.c [Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Natural Resource Sciences, Zhejiang University, Hangzhou 310029 (China)

2010-08-15

Rhizoremediation is a significant form of bioremediation for polycyclic aromatic hydrocarbons (PAHs). This study examined the role of molecular structure in determining the rhizosphere effect on PAHs dissipation. Effect size in meta-analysis was employed as activity dataset for building quantitative structure-activity relationship (QSAR) models and accumulative effect sizes of 16 PAHs were used for validation of these models. Based on the genetic algorithm combined with partial least square regression, models for comprehensive dataset, Poaceae dataset, and Fabaceae dataset were built. The results showed that information indices, calculated as information content of molecules based on the calculation of equivalence classes from the molecular graph, were the most important molecular structural indices for QSAR models of rhizosphere effect on PAHs dissipation. The QSAR model, based on the molecular structure indices and effect size, has potential to be used in studying and predicting the rhizosphere effect of PAHs dissipation. - Effect size based on meta-analysis was used for building PAHs dissipation quantitative structure-activity relationship (QSAR) models.

Quantitative Structure-Activity Relationship Analysis of the ...

African Journals Online (AJOL)

Erah

Quantitative Structure-Activity Relationship Analysis of the Anticonvulsant ... Two types of molecular descriptors, including the 2D autocorrelation ..... It is based on the simulation of natural .... clustering anticonvulsant, antidepressant, and.

Syntheses and absorption-structure relationships of some new ...

Indian Academy of Sciences (India)

New biheterocyclic compound was synthesized as starting material to prepare new photosensitizers mono-, tri-, substituted tri-, azadimethine and mixed cyanine dyes. Absorption-structure relationship of the synthesized cyanine dyes were determined by studying their electronic spectral behaviour in ethanol. The structure of ...

Trichothecenes: structure-toxic activity relationships.

Science.gov (United States)

Wu, Qinghua; Dohnal, Vlastimil; Kuca, Kamil; Yuan, Zonghui

2013-07-01

Trichothecenes comprise a large family of structurally related toxins mainly produced by fungi belonging to the genus Fusarium. Among trichothecenes, type A and type B are of the most concern due to their broad and highly toxic nature. In order to address structure-activity relationships (SAR) of trichothecenes, relationships between structural features and biological effects of trichothecene mycotoxins in mammalian systems are summarized in this paper. The double bond between C-9-C-10 and the 12,13-epoxide ring are essential structural features for trichothecene toxicity. Removal of these groups results in a complete loss of toxicity. A hydroxyl group at C-3 enhances trichothecene toxicity, while this activity decreases gradually when C-3 is substituted with either hydrogen or an acetoxy group. The presence of a hydroxyl group at C-4 promotes slightly lower toxicity than an acetoxy group at the same position. The toxicity for type B trichothecenes decreases if the substituent at C-4 is changed from acetoxy to hydroxyl or hydrogen at C-4 position. The presence of hydroxyl and hydrogen groups on C-15 decreases the trichothecene toxicity in comparison with an acetoxy group attached to this carbon. Trichothecenes toxicity increases when a macrocyclic ring exists between the C-4 and C-15. At C-8 position, an oxygenated substitution at C-8 is essential for trichothecene toxicity, indicating a decrease in the toxicity if substituent change from isovaleryloxy through hydrogen to the hydroxyl group. The presence of a second epoxy ring at C-7-C-8 reduces the toxicity, whereas epoxidation at C-9-C-10 of some macrocyclic trichothecenes increases the activity. Conjugated trichothecenes could release their toxic precursors after hydrolysis in animals, and present an additional potential risk. The SAR study of trichothecenes should provide some crucial information for a better understanding of trichothecene chemical and biological properties in food contamination.

The therapeutic relationship: historical development and contemporary significance.

Science.gov (United States)

O'Brien, A J

2001-04-01

The therapeutic relationship is a concept held by many to be fundamental to the identity of mental health nurses. While the therapeutic relationship was given formal expression in nursing theory in the middle of the last century, its origins can be traced to attendants' interpersonal practices in the asylum era. The dominance of medical understandings of mental distress, and the working-class status of asylum attendants, prevented the development of an account of mental health nursing based on attendants' relationships with asylum inmates. It was left to Peplau and other nursing theorists to describe mental health nursing as a therapeutic relationship in the 1940s and later. Some distinctive features of colonial life in New Zealand suggest that the ideal of the attendant as the embodiment of bourgeoisie values seems particularly unlikely to have been realized in the New Zealand context. However, New Zealand literature from the 20th century shows that the therapeutic relationship, as part of a general development of a therapeutic discourse, came to assume a central place in conceptualizations of mental health nursing. While the therapeutic relationship is not by itself a sufficient basis for professional continuity, it continues to play a fundamental role in mental health nurses' professional identity. The way in which the therapeutic relationship is articulated in the future will determine the meaning of the therapeutic relationship for future generations of mental health nurses.

Verbal Memory Decline following DBS for Parkinson's Disease: Structural Volumetric MRI Relationships.

Science.gov (United States)

Geevarghese, Ruben; Lumsden, Daniel E; Costello, Angela; Hulse, Natasha; Ayis, Salma; Samuel, Michael; Ashkan, Keyoumars

2016-01-01

Parkinson's disease is a chronic degenerative movement disorder. The mainstay of treatment is medical. In certain patients Deep Brain Stimulation (DBS) may be offered. However, DBS has been associated with post-operative neuropsychology changes, especially in verbal memory. Firstly, to determine if pre-surgical thalamic and hippocampal volumes were related to verbal memory changes following DBS. Secondly, to determine if clinical factors such as age, duration of symptoms or motor severity (UPDRS Part III score) were related to verbal memory changes. A consecutive group of 40 patients undergoing bilateral Subthalamic Nucleus (STN)-DBS for PD were selected. Brain MRI data was acquired, pre-processed and structural volumetric data was extracted using FSL. Verbal memory test scores for pre- and post-STN-DBS surgery were recorded. Linear regression was used to investigate the relationship between score change and structural volumetric data. A significant relationship was demonstrated between change in List Learning test score and thalamic (left, p = 0.02) and hippocampal (left, p = 0.02 and right p = 0.03) volumes. Duration of symptoms was also associated with List Learning score change (p = 0.02 to 0.03). Verbal memory score changes appear to have a relationship to pre-surgical MRI structural volumetric data. The findings of this study provide a basis for further research into the use of pre-surgical MRI to counsel PD patients regarding post-surgical verbal memory changes.

Quantitative structure-activation barrier relationship modeling for Diels-Alder ligations utilizing quantum chemical structural descriptors.

Science.gov (United States)

Nandi, Sisir; Monesi, Alessandro; Drgan, Viktor; Merzel, Franci; Novič, Marjana

2013-10-30

In the present study, we show the correlation of quantum chemical structural descriptors with the activation barriers of the Diels-Alder ligations. A set of 72 non-catalysed Diels-Alder reactions were subjected to quantitative structure-activation barrier relationship (QSABR) under the framework of theoretical quantum chemical descriptors calculated solely from the structures of diene and dienophile reactants. Experimental activation barrier data were obtained from literature. Descriptors were computed using Hartree-Fock theory using 6-31G(d) basis set as implemented in Gaussian 09 software. Variable selection and model development were carried out by stepwise multiple linear regression methodology. Predictive performance of the quantitative structure-activation barrier relationship (QSABR) model was assessed by training and test set concept and by calculating leave-one-out cross-validated Q2 and predictive R2 values. The QSABR model can explain and predict 86.5% and 80% of the variances, respectively, in the activation energy barrier training data. Alternatively, a neural network model based on back propagation of errors was developed to assess the nonlinearity of the sought correlations between theoretical descriptors and experimental reaction barriers. A reasonable predictability for the activation barrier of the test set reactions was obtained, which enabled an exploration and interpretation of the significant variables responsible for Diels-Alder interaction between dienes and dienophiles. Thus, studies in the direction of QSABR modelling that provide efficient and fast prediction of activation barriers of the Diels-Alder reactions turn out to be a meaningful alternative to transition state theory based computation.

Brain structure and the relationship with neurocognitive functioning in schizophrenia and bipolar disorder : MRI studies

OpenAIRE

Hartberg, Cecilie Bhandari

2011-01-01

Brain structural abnormalities as well as neurocognitive dysfunction, are found in schizophrenia and in bipolar disorder. Based on the fact that both brain structure and neurocognitive functioning are significantly heritable and affected in both schizophrenia and bipolar disorder, relationships between them are expected. However, previous studies report inconsistent findings. Also, schizophrenia and bipolar disorder are classified as separate disease entities, but demonstrate overlap with reg...

Relationship Structures and Semantic Type Assignments of the UMLS Enriched Semantic Network

Science.gov (United States)

Zhang, Li; Halper, Michael; Perl, Yehoshua; Geller, James; Cimino, James J.

2005-01-01

Objective: The Enriched Semantic Network (ESN) was introduced as an extension of the Unified Medical Language System (UMLS) Semantic Network (SN). Its multiple subsumption configuration and concomitant multiple inheritance make the ESN's relationship structures and semantic type assignments different from those of the SN. A technique for deriving the relationship structures of the ESN's semantic types and an automated technique for deriving the ESN's semantic type assignments from those of the SN are presented. Design: The technique to derive the ESN's relationship structures finds all newly inherited relationships in the ESN. All such relationships are audited for semantic validity, and the blocking mechanism is used to block invalid relationships. The mapping technique to derive the ESN's semantic type assignments uses current SN semantic type assignments and preserves nonredundant categorizations, while preventing new redundant categorizations. Results: Among the 426 newly inherited relationships, 326 are deemed valid. Seven blockings are applied to avoid inheritance of the 100 invalid relationships. Sixteen semantic types have different relationship structures in the ESN as compared to those in the SN. The mapping of semantic type assignments from the SN to the ESN avoids the generation of 26,950 redundant categorizations. The resulting ESN contains 138 semantic types, 149 IS-A links, 7,303 relationships, and 1,013,876 semantic type assignments. Conclusion: The ESN's multiple inheritance provides more complete relationship structures than in the SN. The ESN's semantic type assignments avoid the existing redundant categorizations appearing in the SN and prevent new ones that might arise due to multiple parents. Compared to the SN, the ESN provides a more accurate unifying semantic abstraction of the UMLS Metathesaurus. PMID:16049233

Factors correlating with significant differences between X-ray structures of myoglobin

International Nuclear Information System (INIS)

Rashin, Alexander A.; Domagalski, Marcin J.; Zimmermann, Michael T.; Minor, Wladek; Chruszcz, Maksymilian; Jernigan, Robert L.

2014-01-01

Conformational differences between myoglobin structures are studied. Most structural differences in whale myoglobin beyond the uncertainty threshold can be correlated with a few specific structural factors. There are always exceptions and a search for additional factors is needed. The results might have serious implications for biological insights from conformational differences. Validation of general ideas about the origins of conformational differences in proteins is critical in order to arrive at meaningful functional insights. Here, principal component analysis (PCA) and distance difference matrices are used to validate some such ideas about the conformational differences between 291 myoglobin structures from sperm whale, horse and pig. Almost all of the horse and pig structures form compact PCA clusters with only minor coordinate differences and outliers that are easily explained. The 222 whale structures form a few dense clusters with multiple outliers. A few whale outliers with a prominent distortion of the GH loop are very similar to the cluster of horse structures, which all have a similar GH-loop distortion apparently owing to intermolecular crystal lattice hydrogen bonds to the GH loop from residues near the distal histidine His64. The variations of the GH-loop coordinates in the whale structures are likely to be owing to the observed alternative intermolecular crystal lattice bond, with the change to the GH loop distorting bonds correlated with the binding of specific ‘unusual’ ligands. Such an alternative intermolecular bond is not observed in horse myoglobins, obliterating any correlation with the ligands. Intermolecular bonds do not usually cause significant coordinate differences and cannot be validated as their universal cause. Most of the native-like whale myoglobin structure outliers can be correlated with a few specific factors. However, these factors do not always lead to coordinate differences beyond the previously determined uncertainty

Factors correlating with significant differences between X-ray structures of myoglobin

Energy Technology Data Exchange (ETDEWEB)

Rashin, Alexander A., E-mail: alexander-rashin@hotmail.com [BioChemComp Inc., 543 Sagamore Avenue, Teaneck, NJ 07666 (United States); Iowa State University, 112 Office and Lab Bldg, Ames, IA 50011-3020 (United States); Domagalski, Marcin J. [University of Virginia, 1340 Jefferson Park Avenue, Jordan Hall, Room 4223, Charlottesville, VA 22908 (United States); Zimmermann, Michael T. [Iowa State University, 112 Office and Lab Bldg, Ames, IA 50011-3020 (United States); Minor, Wladek [University of Virginia, 1340 Jefferson Park Avenue, Jordan Hall, Room 4223, Charlottesville, VA 22908 (United States); Chruszcz, Maksymilian [University of Virginia, 1340 Jefferson Park Avenue, Jordan Hall, Room 4223, Charlottesville, VA 22908 (United States); University of South Carolina, 631 Sumter Street, Columbia, SC 29208 (United States); Jernigan, Robert L. [Iowa State University, 112 Office and Lab Bldg, Ames, IA 50011-3020 (United States); BioChemComp Inc., 543 Sagamore Avenue, Teaneck, NJ 07666 (United States)

2014-02-01

Conformational differences between myoglobin structures are studied. Most structural differences in whale myoglobin beyond the uncertainty threshold can be correlated with a few specific structural factors. There are always exceptions and a search for additional factors is needed. The results might have serious implications for biological insights from conformational differences. Validation of general ideas about the origins of conformational differences in proteins is critical in order to arrive at meaningful functional insights. Here, principal component analysis (PCA) and distance difference matrices are used to validate some such ideas about the conformational differences between 291 myoglobin structures from sperm whale, horse and pig. Almost all of the horse and pig structures form compact PCA clusters with only minor coordinate differences and outliers that are easily explained. The 222 whale structures form a few dense clusters with multiple outliers. A few whale outliers with a prominent distortion of the GH loop are very similar to the cluster of horse structures, which all have a similar GH-loop distortion apparently owing to intermolecular crystal lattice hydrogen bonds to the GH loop from residues near the distal histidine His64. The variations of the GH-loop coordinates in the whale structures are likely to be owing to the observed alternative intermolecular crystal lattice bond, with the change to the GH loop distorting bonds correlated with the binding of specific ‘unusual’ ligands. Such an alternative intermolecular bond is not observed in horse myoglobins, obliterating any correlation with the ligands. Intermolecular bonds do not usually cause significant coordinate differences and cannot be validated as their universal cause. Most of the native-like whale myoglobin structure outliers can be correlated with a few specific factors. However, these factors do not always lead to coordinate differences beyond the previously determined uncertainty

[Volunteer satisfaction: Internal structure and relationship with permanence in organizations].

Science.gov (United States)

Vecina Jiménez, M L; Chacón Fuertes, Fernando; Sueiro Abad, Manuel J

2009-02-01

Volunteer satisfaction: Internal structure and relationship with permanence in organizations. The concept of satisfaction is considered theoretically relevant in practically all the studies that have investigated the factors that influence the permanence of volunteer participation in organizations. However, the practical results are not conclusive, perhaps due to the wide range of ways in which the concept is understood and measured. The object of this study is: to analyse the internal structure of satisfaction and to verify its relationship with volunteer duration in organizations. The results of the factor analysis yield a three-factor structure: Satisfaction with the management of the organization, Satisfaction with the tasks, Satisfaction of motivations. The three factors allow us to differentiate between individuals who remain in the organization for a period of 12 consecutive months, and those who leave earlier. The results of structural equation model analysis show that the relationship between satisfaction and the length of time that volunteers stay with the organization is affected by the intention to remain.

Significant others and contingencies of self-worth: activation and consequences of relationship-specific contingencies of self-worth.

Science.gov (United States)

Horberg, E J; Chen, Serena

2010-01-01

Three studies tested the activation and consequences of contingencies of self-worth associated with specific significant others, that is, relationship-specific contingencies of self-worth. The results showed that activating the mental representation of a significant other with whom one strongly desires closeness led participants to stake their self-esteem in domains in which the significant other wanted them to excel. This was shown in terms of self-reported contingencies of self-worth (Study 1), in terms of self-worth after receiving feedback on a successful or unsatisfactory performance in a relationship-specific contingency domain (Study 2), and in terms of feelings of reduced self-worth after thinking about a failure in a relationship-specific contingency domain (Study 3). Across studies, a variety of contingency domains were examined. Furthermore, Study 3 showed that failing in an activated relationship-specific contingency domain had negative implications for current feelings of closeness and acceptance in the significant-other relationship. Overall, the findings suggest that people's contingencies of self-worth depend on the social situation and that performance in relationship-specific contingency domains can influence people's perceptions of their relationships.

The Relationship of Clinical Nurses' Perceptions of Structural and Psychological Empowerment and Engagement on Their Unit.

Science.gov (United States)

DiNapoli, Jean Marie; O'Flaherty, Deirdre; Musil, Carol; Clavelle, Joanne T; Fitzpatrick, Joyce J

2016-02-01

The purpose of this study was to describe relationships between structural empowerment, psychological empowerment, and engagement among clinical nurses. Empowerment and engagement are key drivers of retention and quality in healthcare. Creating an empowering culture and an engaged staff supports initiatives that are essential for positive work environments. A survey of 280 nurses in a national conference was conducted using the Conditions of Work Effectiveness, Psychological Empowerment Instrument, and the Utrecht Work Engagement Scale. Pearson correlation coefficients and multiple regression analysis were used to determine relationships between demographic data and study variables. Overall, nurses had high perceptions of structural empowerment and psychological empowerment and were moderately engaged. Also, significant positive relationships were found between the key study variables. Results show positive correlations between empowerment and perceived engagement among clinical nurses.

Structure-activity relationship studies of citalopram derivatives

DEFF Research Database (Denmark)

Larsen, M Andreas B; Plenge, Per; Andersen, Jacob

2016-01-01

towards the S2 site. EXPERIMENTAL APPROACH: We performed a systematic structure-activity relationship study based on the scaffold of citalopram and the structurally closely related congener, talopram, that shows low-affinity S1 binding in SERT. The role of the four chemical substituents, which distinguish...... citalopram from talopram in conferring selectivity towards the S1 and S2 site, respectively, was assessed by determining the binding of 14 citalopram/talopram analogous to the S1 and S2 binding sites in SERT using membranes of COS7 cells transiently expressing SERT. KEY RESULTS: The structure-activity...

Molecular Descriptors Family on Structure Activity Relationships 1. Review of the Methodology

Directory of Open Access Journals (Sweden)

Lorentz JÄNTSCHI

2005-01-01

Full Text Available This review cumulates the knowledge about the use of Molecular Descriptors Family usage on Structure Activity Relationships. The methodology is augmented through the general Structure Activity Relationships methodology. The obtained models in a series of five papers are quantitatively analyzed by comparing with previous reported results by using of the correlated correlations tests. The scores for a series of 13 data sets unpublished yet results are presented. Two unrestricted online access portals to the Molecular Descriptors Family Structure Activity Relationship models results are given.

Structure-function relationship of skeletal muscle provides inspiration for design of new artificial muscle

Science.gov (United States)

Gao, Yingxin; Zhang, Chi

2015-03-01

A variety of actuator technologies have been developed to mimic biological skeletal muscle that generates force in a controlled manner. Force generation process of skeletal muscle involves complicated biophysical and biochemical mechanisms; therefore, it is impossible to replace biological muscle. In biological skeletal muscle tissue, the force generation of a muscle depends not only on the force generation capacity of the muscle fiber, but also on many other important factors, including muscle fiber type, motor unit recruitment, architecture, structure and morphology of skeletal muscle, all of which have significant impact on the force generation of the whole muscle or force transmission from muscle fibers to the tendon. Such factors have often been overlooked, but can be incorporated in artificial muscle design, especially with the discovery of new smart materials and the development of innovative fabrication and manufacturing technologies. A better understanding of the physiology and structure-function relationship of skeletal muscle will therefore benefit the artificial muscle design. In this paper, factors that affect muscle force generation are reviewed. Mathematical models used to model the structure-function relationship of skeletal muscle are reviewed and discussed. We hope the review will provide inspiration for the design of a new generation of artificial muscle by incorporating the structure-function relationship of skeletal muscle into the design of artificial muscle.

Uncovering the structure-function relationship in spider silk

Science.gov (United States)

Yarger, Jeffery L.; Cherry, Brian R.; van der Vaart, Arjan

2018-03-01

All spiders produce protein-based biopolymer fibres that we call silk. The most studied of these silks is spider dragline silk, which is very tough and relatively abundant compared with other types of spider silks. Considerable research has been devoted to understanding the relationship between the molecular structure and mechanical properties of spider dragline silks. In this Review, we overview experimental and computational studies that have provided a wealth of detail at the molecular level on the highly conserved repetitive core and terminal regions of spider dragline silk. We also discuss the role of the nanocrystalline β-sheets and amorphous regions in determining the properties of spider silk fibres, endowing them with strength and elasticity. Additionally, we outline imaging techniques and modelling studies that elucidate the importance of the hierarchical structure of silk fibres at the molecular level. These insights into structure-function relationships can guide the reverse engineering of spider silk to enable the production of superior synthetic fibres.

Bank Image Structure: The Relationship to Consumer Behaviour

Directory of Open Access Journals (Sweden)

Lukasova Ruzena

2014-03-01

Full Text Available This paper presents the results of a study of the relationship between the bank image, its structure as a reflection in the minds of individuals and behavioural tendencies in relation to banks. Attitudinal scales were used to identify the contents of the particular banks’ image. The structure of the image was identified by means of factor analysis. The study found that the respondents’ behavioural tendencies, i.e. their willingness to be a client of or to recommend a particular bank, are related to different content components of particular banks and mainly to respondents’ needs. Based on the results, the study identifies the danger that the results of the bank image analysis can be misinterpreted if the respondents’ relationship to the bank is underestimated.

Relationship Structure, Relationship Texture: Case Studies in Non/Monogamies Research

Directory of Open Access Journals (Sweden)

Jessica Joan Kean

2017-05-01

Full Text Available This article develops case studies from qualitative interviews with people in negotiated non-monogamous relationships to ask what discursive or practical factors besides non/monogamy might play a role in assessments of a relationship’s structure or worth. Beginning with an auto-ethnographic reflection on the way the ‘significance’ was recognised and misrecognised in one polyamorous ‘thrupple’, I introduce three case studies of people in negotiated non-monogamous relationships in order to bring a cultural studies method of the particular to the study of intimacy. For the individuals in these case studies, the practice and experience of non/monogamy is inextricably linked to the ideas and practices surrounding gender, sexuality, sex work, friendship, HIV status and ability. Sketching a middle path between the romantic’s dream of love as a state of exception or exemption from the social and the theorist’s map of the patterned effects of hetero- and mono-normativities, this article attends to the contingency, flexibility and incoherence which so often underpins the sense we make of relationships, even as that sense is shaped by the practices, ideals and institutions of intimacy, love and friendship.

Impact of functional and structural social relationships on two year depression outcomes: A multivariate analysis.

Science.gov (United States)

Davidson, Sandra K; Dowrick, Christopher F; Gunn, Jane M

2016-03-15

High rates of persistent depression highlight the need to identify the risk factors associated with poor depression outcomes and to provide targeted interventions to people at high risk. Although social relationships have been implicated in depression course, interventions targeting social relationships have been disappointing. Possibly, interventions have targeted the wrong elements of relationships. Alternatively, the statistical association between relationships and depression course is not causal, but due to shared variance with other factors. We investigated whether elements of social relationships predict major depressive episode (MDE) when multiple relevant variables are considered. Data is from a longitudinal study of primary care patients with depressive symptoms. 494 participants completed questionnaires at baseline and a depression measure (PHQ-9) two years later. Baseline measures included functional (i.e. quality) and structural (i.e. quantity) social relationships, depression, neuroticism, chronic illness, alcohol abuse, childhood abuse, partner violence and sociodemographic characteristics. Logistic regression with generalised estimating equations was used to estimate the association between social relationships and MDE. Both functional and structural social relationships predicted MDE in univariate analysis. Only functional social relationships remained significant in multivariate analysis (OR: 0.87; 95%CI: 0.79-0.97; p=0.01). Other unique predictors of MDE were baseline depression severity, neuroticism, childhood sexual abuse and intimate partner violence. We did not assess how a person's position in their depression trajectory influenced the association between social relationships and depression. Interventions targeting relationship quality may be part of a personalised treatment plan for people at high risk due of persistent depression due to poor social relationships. Copyright © 2015 Elsevier B.V. All rights reserved.

Structure-function relationship in complex brain networks expressed by hierarchical synchronization

International Nuclear Information System (INIS)

Zhou Changsong; Zemanova, Lucia; Zamora-Lopez, Gorka; Hilgetag, Claus C; Kurths, Juergen

2007-01-01

The brain is one of the most complex systems in nature, with a structured complex connectivity. Recently, large-scale corticocortical connectivities, both structural and functional, have received a great deal of research attention, especially using the approach of complex network analysis. Understanding the relationship between structural and functional connectivity is of crucial importance in neuroscience. Here we try to illuminate this relationship by studying synchronization dynamics in a realistic anatomical network of cat cortical connectivity. We model the nodes (cortical areas) by a neural mass model (population model) or by a subnetwork of interacting excitable neurons (multilevel model). We show that if the dynamics is characterized by well-defined oscillations (neural mass model and subnetworks with strong couplings), the synchronization patterns are mainly determined by the node intensity (total input strengths of a node) and the detailed network topology is rather irrelevant. On the other hand, the multilevel model with weak couplings displays more irregular, biologically plausible dynamics, and the synchronization patterns reveal a hierarchical cluster organization in the network structure. The relationship between structural and functional connectivity at different levels of synchronization is explored. Thus, the study of synchronization in a multilevel complex network model of cortex can provide insights into the relationship between network topology and functional organization of complex brain networks

Structure-function relationship in complex brain networks expressed by hierarchical synchronization

Energy Technology Data Exchange (ETDEWEB)

Zhou Changsong [Institute of Physics, University of Potsdam, PF 601553, 14415 Potsdam (Germany); Zemanova, Lucia [Institute of Physics, University of Potsdam, PF 601553, 14415 Potsdam (Germany); Zamora-Lopez, Gorka [Institute of Physics, University of Potsdam, PF 601553, 14415 Potsdam (Germany); Hilgetag, Claus C [Jacobs University Bremen, Campus Ring 6, Rm 116, D-28759 Bremen (Germany); Kurths, Juergen [Institute of Physics, University of Potsdam, PF 601553, 14415 Potsdam (Germany)

2007-06-15

The brain is one of the most complex systems in nature, with a structured complex connectivity. Recently, large-scale corticocortical connectivities, both structural and functional, have received a great deal of research attention, especially using the approach of complex network analysis. Understanding the relationship between structural and functional connectivity is of crucial importance in neuroscience. Here we try to illuminate this relationship by studying synchronization dynamics in a realistic anatomical network of cat cortical connectivity. We model the nodes (cortical areas) by a neural mass model (population model) or by a subnetwork of interacting excitable neurons (multilevel model). We show that if the dynamics is characterized by well-defined oscillations (neural mass model and subnetworks with strong couplings), the synchronization patterns are mainly determined by the node intensity (total input strengths of a node) and the detailed network topology is rather irrelevant. On the other hand, the multilevel model with weak couplings displays more irregular, biologically plausible dynamics, and the synchronization patterns reveal a hierarchical cluster organization in the network structure. The relationship between structural and functional connectivity at different levels of synchronization is explored. Thus, the study of synchronization in a multilevel complex network model of cortex can provide insights into the relationship between network topology and functional organization of complex brain networks.

Materials science in microelectronics I the relationships between thin film processing and structure

CERN Document Server

Machlin, Eugene

2005-01-01

Thin films play a key role in the material science of microelectronics, and the subject matter of thin-films divides naturally into two headings: processing / structure relationship, and structure / properties relationship.The first volume of Materials Science in Microelectronics focuses on the first relationship - that between processing and the structure of the thin-film. The state of the thin film's surface during the period that one monolayer exists - before being buried in the next layer - determines the ultimate structure of the thin film, and thus its properties. This

The significance of interfamilial relationships on birth preparedness and complication readiness in Pakistan.

Science.gov (United States)

Ghani, Usman; Crowther, Susan; Kamal, Yasir; Wahab, Muhammad

2018-03-29

In the interests of improving maternal health care and survival, the issue of birth preparedness and complication readiness has been much debated and has remained a priority for the international health community. The provision of birth preparedness and complications readiness is determined by a range of different factors. The main aim of this study is to identify and measure the influence of husbands and other family relationships on birth preparedness and complications readiness in the Khyber Pakhtunkhwa province of Pakistan. This study is a cross-sectional exploratory study. Data was collected through a survey questionnaire. Logistic regression and descriptive analysis was used. Analysis indicated that the mother-in-law's role, men's and women's level of education and interfamilial relationships are still the most significant factors influencing birth preparedness and complications readiness. Of the respondents, 86% were receiving antenatal care and 76.5% were planning for the birth to take place in state-run hospitals or private obstetric and gynae clinics. The tendency to take up antenatal care in Khyber Pakhtunkhwa can mainly be credited to a mutual understanding between husband and wife and a good relationship between the woman and her mother-in-law. Highlighting the significance of these relationships has implications for ensuring birth preparedness and complications readiness. Copyright © 2018 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Comparative genomics of the relationship between gene structure and expression

NARCIS (Netherlands)

Ren, X.

2006-01-01

The relationship between the structure of genes and their expression is a relatively new aspect of genome organization and regulation. With more genome sequences and expression data becoming available, bioinformatics approaches can help the further elucidation of the relationships between gene

Redox properties of structural Fe in clay minerals: 3. Relationships between smectite redox and structural properties.

Science.gov (United States)

Gorski, Christopher A; Klüpfel, Laura E; Voegelin, Andreas; Sander, Michael; Hofstetter, Thomas B

2013-01-01

Structural Fe in clay minerals is an important redox-active species in many pristine and contaminated environments as well as in engineered systems. Understanding the extent and kinetics of redox reactions involving Fe-bearing clay minerals has been challenging due to the inability to relate structural Fe(2+)/Fe(total) fractions to fundamental redox properties, such as reduction potentials (EH). Here, we overcame this challenge by using mediated electrochemical reduction (MER) and oxidation (MEO) to characterize the fraction of redox-active structural Fe (Fe(2+)/Fe(total)) in smectites over a wide range of applied EH-values (-0.6 V to +0.6 V). We examined Fe(2+)/Fe(total )- EH relationships of four natural Fe-bearing smectites (SWy-2, SWa-1, NAu-1, NAu-2) in their native, reduced, and reoxidized states and compared our measurements with spectroscopic observations and a suite of mineralogical properties. All smectites exhibited unique Fe(2+)/Fe(total) - EH relationships, were redox active over wide EH ranges, and underwent irreversible electron transfer induced structural changes that were observable with X-ray absorption spectroscopy. Variations among the smectite Fe(2+)/Fe(total) - EH relationships correlated well with both bulk and molecular-scale properties, including Fe(total) content, layer charge, and quadrupole splitting values, suggesting that multiple structural parameters determined the redox properties of smectites. The Fe(2+)/Fe(total) - EH relationships developed for these four commonly studied clay minerals may be applied to future studies interested in relating the extent of structural Fe reduction or oxidation to EH-values.

Quantitative structure carcinogenicity relationship for detecting structural alerts in nitroso-compounds

International Nuclear Information System (INIS)

Helguera, Aliuska Morales; Cordeiro, M. Natalia D.S.; Perez, Miguel Angel Cabrera; Combes, Robert D.; Gonzalez, Maykel Perez

2008-01-01

In this work, Quantitative Structure-Activity Relationship (QSAR) modelling was used as a tool for predicting the carcinogenic potency of a set of 39 nitroso-compounds, which have been bioassayed in male rats by using the oral route of administration. The optimum QSAR model provided evidence of good fit and performance of predicitivity from training set. It was able to account for about 84% of the variance in the experimental activity and exhibited high values of the determination coefficients of cross validations, leave one out and bootstrapping (q 2 LOO = 78.53 and q 2 Boot = 74.97). Such a model was based on spectral moments weighted with Gasteiger-Marsilli atomic charges, polarizability and hydrophobicity, as well as with Abraham indexes, specifically the summation solute hydrogen bond basicity and the combined dipolarity/polarizability. This is the first study to have explored the possibility of combining Abraham solute descriptors with spectral moments. A reasonable interpretation of these molecular descriptors from a toxicological point of view was achieved by means of taking into account bond contributions. The set of relationships so derived revealed the importance of the length of the alkyl chains for determining carcinogenic potential of the chemicals analysed, and were able to explain the difference between mono-substituted and di-substituted nitrosoureas as well as to discriminate between isomeric structures with hydroxyl-alkyl and alkyl substituents in different positions. Moreover, they allowed the recognition of structural alerts in classical structures of two potent nitrosamines, consistent with their biotransformation. These results indicate that this new approach has the potential for improving carcinogenicity predictions based on the identification of structural alerts

Composition-Structure-Property Relationships in Boroaluminosilicate Glasses

DEFF Research Database (Denmark)

Zheng, Qiuju; Potuzak, M.; Mauro, J.C.

2012-01-01

boroaluminosilicate glasses from peralkaline to peraluminous compositions by substituting Al2O3 for SiO2. Our results reveal a pronounced change in all the measured physical properties (density, elastic moduli, hardness, glass transition temperature, and liquid fragility) around [Al2O3]–[Na2O]=0. The structural......The complicated structural speciation in boroaluminosilicate glasses leads to a mixed network former effect yielding nonlinear variation in many macroscopic properties as a function of chemical composition. Here we study the composition–structure–property relationships in a series of sodium...

Modeling process-structure-property relationships for additive manufacturing

Science.gov (United States)

Yan, Wentao; Lin, Stephen; Kafka, Orion L.; Yu, Cheng; Liu, Zeliang; Lian, Yanping; Wolff, Sarah; Cao, Jian; Wagner, Gregory J.; Liu, Wing Kam

2018-02-01

This paper presents our latest work on comprehensive modeling of process-structure-property relationships for additive manufacturing (AM) materials, including using data-mining techniques to close the cycle of design-predict-optimize. To illustrate the processstructure relationship, the multi-scale multi-physics process modeling starts from the micro-scale to establish a mechanistic heat source model, to the meso-scale models of individual powder particle evolution, and finally to the macro-scale model to simulate the fabrication process of a complex product. To link structure and properties, a highefficiency mechanistic model, self-consistent clustering analyses, is developed to capture a variety of material response. The model incorporates factors such as voids, phase composition, inclusions, and grain structures, which are the differentiating features of AM metals. Furthermore, we propose data-mining as an effective solution for novel rapid design and optimization, which is motivated by the numerous influencing factors in the AM process. We believe this paper will provide a roadmap to advance AM fundamental understanding and guide the monitoring and advanced diagnostics of AM processing.

The Ghosts of Acetylcholine : structure-activity relationships of ...

African Journals Online (AJOL)

The Ghosts of Acetylcholine : structure-activity relationships of muscle relaxants : registrar communication. ... AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

Evidence for the functional significance of diazotroph community structure in soil.

Science.gov (United States)

Hsu, Shi-Fang; Buckley, Daniel H

2009-01-01

Microbial ecologists continue to seek a greater understanding of the factors that govern the ecological significance of microbial community structure. Changes in community structure have been shown to have functional significance for processes that are mediated by a narrow spectrum of organisms, such as nitrification and denitrification, but in some cases, functional redundancy in the community seems to buffer microbial ecosystem processes. The functional significance of microbial community structure is frequently obscured by environmental variation and is hard to detect in short-term experiments. We examine the functional significance of free-living diazotrophs in a replicated long-term tillage experiment in which extraneous variation is minimized and N-fixation rates can be related to soil characteristics and diazotroph community structure. Soil characteristics were found to be primarily impacted by tillage management, whereas N-fixation rates and diazotroph community structure were impacted by both biomass management practices and interactions between tillage and biomass management. The data suggest that the variation in diazotroph community structure has a greater impact on N-fixation rates than do soil characteristics at the site. N-fixation rates displayed a saturating response to increases in diazotroph community diversity. These results show that the changes in the community structure of free-living diazotrophs in soils can have ecological significance and suggest that this response is related to a change in community diversity.

Structural mode significance using INCA. [Interactive Controls Analysis computer program

Science.gov (United States)

Bauer, Frank H.; Downing, John P.; Thorpe, Christopher J.

1990-01-01

Structural finite element models are often too large to be used in the design and analysis of control systems. Model reduction techniques must be applied to reduce the structural model to manageable size. In the past, engineers either performed the model order reduction by hand or used distinct computer programs to retrieve the data, to perform the significance analysis and to reduce the order of the model. To expedite this process, the latest version of INCA has been expanded to include an interactive graphical structural mode significance and model order reduction capability.

Relationships between structural complexity, coral traits, and reef fish assemblages

Science.gov (United States)

Darling, Emily S.; Graham, Nicholas A. J.; Januchowski-Hartley, Fraser A.; Nash, Kirsty L.; Pratchett, Morgan S.; Wilson, Shaun K.

2017-06-01

With the ongoing loss of coral cover and the associated flattening of reef architecture, understanding the links between coral habitat and reef fishes is of critical importance. Here, we investigate whether considering coral traits and functional diversity provides new insights into the relationship between structural complexity and reef fish communities, and whether coral traits and community composition can predict structural complexity. Across 157 sites in Seychelles, Maldives, the Chagos Archipelago, and Australia's Great Barrier Reef, we find that structural complexity and reef zone are the strongest and most consistent predictors of reef fish abundance, biomass, species richness, and trophic structure. However, coral traits, diversity, and life histories provided additional predictive power for models of reef fish assemblages, and were key drivers of structural complexity. Our findings highlight that reef complexity relies on living corals—with different traits and life histories—continuing to build carbonate skeletons, and that these nuanced relationships between coral assemblages and habitat complexity can affect the structure of reef fish assemblages. Seascape-level estimates of structural complexity are rapid and cost effective with important implications for the structure and function of fish assemblages, and should be incorporated into monitoring programs.

Family structure and its relationship to travel

Science.gov (United States)

Christine Cornell McCreedy; Joseph T. O' Leary; Daniel Fesenmaier

1992-01-01

This paper examines the relationship between family structure and travel to further understand what differences exist between family groups. Results indicate that the absence of a husband delays travel for single mothers and that they are not as well-off as their married counterparts. We examine other travel and leisure studies to make comparisons with these data,...

The effect of leverage and/or influential on structure-activity relationships.

Science.gov (United States)

Bolboacă, Sorana D; Jäntschi, Lorentz

2013-05-01

In the spirit of reporting valid and reliable Quantitative Structure-Activity Relationship (QSAR) models, the aim of our research was to assess how the leverage (analysis with Hat matrix, h(i)) and the influential (analysis with Cook's distance, D(i)) of QSAR models may reflect the models reliability and their characteristics. The datasets included in this research were collected from previously published papers. Seven datasets which accomplished the imposed inclusion criteria were analyzed. Three models were obtained for each dataset (full-model, h(i)-model and D(i)-model) and several statistical validation criteria were applied to the models. In 5 out of 7 sets the correlation coefficient increased when compounds with either h(i) or D(i) higher than the threshold were removed. Withdrawn compounds varied from 2 to 4 for h(i)-models and from 1 to 13 for D(i)-models. Validation statistics showed that D(i)-models possess systematically better agreement than both full-models and h(i)-models. Removal of influential compounds from training set significantly improves the model and is recommended to be conducted in the process of quantitative structure-activity relationships developing. Cook's distance approach should be combined with hat matrix analysis in order to identify the compounds candidates for removal.

Relationship between Temperament, Depression, Anxiety, and Hopelessness in Adolescents: A Structural Equation Model

Directory of Open Access Journals (Sweden)

Paolo Iliceto

2011-01-01

Full Text Available The purpose of this study was to test the validity of affective temperaments for predicting psychiatric morbidity and suicide risk, using a two-factor model to explain the relationships between temperament, anxiety, depression, and hopelessness. We investigated 210 high school students, 103 males and 107 females, 18-19 years old, who were administered self-report questionnaires to assess temperament (TEMPS-A, depression (BDI-II, anxiety (STAI and hopelessness (BHS. The final structural model had a good fit with the data, with two factors significantly correlated, the first labeled unstable cyclothymic temperament including Dysthymic/Cyclothymic/Anxious temperament, Irritable temperament and Depression, and the second labeled Demoralization including Anxiety (State/Trait and Hopelessness. Depression, anxiety and hopelessness are in a complex relationship partly mediated by temperament.

Perceptions of self, significant others, and teacher-child relationships in indiscriminately friendly children.

Science.gov (United States)

Vervoort, Eleonora; Bosmans, Guy; Doumen, Sarah; Minnis, Helen; Verschueren, Karine

2014-11-01

Despite increasing research on indiscriminate friendliness in children, almost no research exists on social-cognitive deficits that are supposed to underlie indiscriminately friendly behavior. In this study, we compared indiscriminately friendly children with controls regarding their perceptions of self, reliability trust in significant others, and perceptions of the teacher-child relationship. Children's perceptions were compared in two samples: a sample of 33 likely cases for disinhibited reactive attachment disorder (RAD) from special education for children with emotional and behavioral disorders (75.76% boys, Mage=8.52, 96.9% Caucasian, 33.3% and 45.5% of their mothers completed primary or secondary education, respectively) was matched on sex, age, and socio-economic status with a sample of 33 controls from general education. Children participated individually in several interviews assessing global and social self-concept, reliability trust in significant others, teacher-child relationship perceptions, and vocabulary. Parents and teachers completed a screening questionnaire for RAD and the Strengths and Difficulties Questionnaire. Likely disinhibited RAD-cases showed more indiscriminate friendliness and more problem behavior in general according to their parents and teachers than controls. Furthermore, likely RAD-cases reported a more positive global self-concept, more reliability trust in significant others, and more dependency in the teacher-child relationship than controls. The results are in line with clinical observations of indiscriminately friendly children and findings in clinical samples of maltreated or attachment disrupted children but contrast hypotheses from developmental attachment research. Further research is needed to explain the more positive perceptions of indiscriminately friendly children. Copyright © 2014 Elsevier Ltd. All rights reserved.

Structuring strategy and relationships in North American gas markets

International Nuclear Information System (INIS)

Fisher, J.

1998-01-01

Duke Energy's experience in strategy development and structuring relationships with other companies were described. Included was a description of their partnership with PanEnergy and Mobil and a merger between PanEnergy and Duke. In developing their growth strategy, Duke Energy was guided by the following considerations: (1) an assessment of the market, (2) the identification of opportunities, (3) a self-assessment, (4) the establishment of goals, and (5) determining strategic alternatives. The advantages and disadvantages of different structuring relationships were reviewed. Duke Energy's approach to Ontario's residential market and their agreement with Alliance Gas Management were also discussed. The goal of the Alliance Gas management agreement was to simplify Alliance's wholesale gas supply management needs and to allow Alliance access to diverse gas supplies. figs

Significance of Operating Environment in Condition Monitoring of Large Civil Structures

OpenAIRE

Alampalli, Sreenivas

1999-01-01

Success of remote long-term condition monitoring of large civil structures and developing calibrated analytical models for damage detection, depend significantly on establishing accurate baseline signatures and their sensitivity. Most studies reported in the literature concentrated on the effect of structural damage on modal parameters without emphasis on reliability of modal parameters. Thus, a field bridge structure was studied for the significance of operating conditions in relation to bas...

Critical zone structure controls concentration-discharge relationships and solute generation in forested tropical montane watersheds

Science.gov (United States)

Wymore, Adam S.; Brereton, Richard L.; Ibarra, Daniel E.; Maher, Kate; McDowell, William H.

2017-07-01

Concentration-discharge (C-Q) relationships are poorly known for tropical watersheds, even though the tropics contribute a disproportionate amount of solutes to the global ocean. The Luquillo Mountains in Puerto Rico offer an ideal environment to examine C-Q relationships across a heterogeneous tropical landscape. We use 10-30 years of weekly stream chemistry data across 10 watersheds to examine C-Q relationships for weathering products (SiO2(aq), Ca2+, Mg2+, and Na+) and biologically controlled solutes (dissolved organic carbon [DOC], dissolved organic nitrogen [DON], NH4+, NO3-, PO43-, K+, and SO42-). We analyze C-Q relationships using power law equations and a solute production model and use principal component analysis to test hypotheses regarding how the structure of the critical zone controls solute generation. Volcaniclastic watersheds had higher concentrations of weathering solutes and smaller tributaries were approximately threefold more efficient at generating these solutes than larger rivers. Lithology and vegetation explained a significant amount of variation in the theoretical maximum concentrations of weathering solutes (r2 = 0.43-0.48) and in the C-Q relationships of PO43- (r2 = 0.63) and SiO2(aq) (r2 = 0.47). However, the direction and magnitude of these relationships varied. Across watersheds, various forms of N and P displayed variable C-Q relationships, while DOC was consistently enriched with increasing discharge. Results suggest that PO43- may be a useful indicator of watershed function. Relationships between C-Q and landscape characteristics indicate the extent to which the structure and function of the Critical zone controls watershed solute fluxes.

The relationship between Prostate CAncer gene 3 (PCA3) and prostate cancer significance

NARCIS (Netherlands)

van Poppel, Hein; Haese, Alexander; Graefen, Markus; de la Taille, Alexandre; Irani, Jacques; de Reijke, Theo; Remzi, Mesut; Marberger, Michael

2012-01-01

OBJECTIVE To evaluate the relationship between Prostate CAncer gene 3 (PCA3) and prostate cancer significance. PATIENTS AND METHODS Clinical data from two multi-centre European open-label, prospective studies evaluating the clinical utility of the PCA3 assay in guiding initial and repeat biopsy

Quantitative structure-toxicity relationship study of some natural and synthetic coumarins using retention parameters

Directory of Open Access Journals (Sweden)

Rabtti El Hadi M.A.

2012-01-01

Full Text Available Four lipophilicity descriptors (RM0, b, C0, PC1 for twelve coumarine derivatives were determined by reversed-phase thin-layer chromatography in order to analyze which descriptor best describes the lipophilicity of coumarines investigated. Moreover, possible chemical toxicity of coumarins, expressed as the probability of a compound to cause organ-specific health effects, was calculated using ACD/Tox Suite program. The quantitative relationships between toxicity and molecular descriptors, including experimentally determined lipophilicity descriptors obtained in current study, were investigated using partial least square regression. The best models were obtained for kidney and liver health effects. Quantitative structure-toxicity relationship models revealed the importance of electric polarization descriptors, size descriptors and lipophilicity descriptors. Obtained models were used for the selection of the structural features of the compounds that are significantly affecting their absorption, distribution, metabolism, excretion, and toxicity. [Acknowledgements. This work has been supported by the Ministry of Education and Science of Serbia, Grant 172017.

Quantitative structure-activity relationship of some 1-benzylbenzimidazole derivatives as antifungal agents

Directory of Open Access Journals (Sweden)

Podunavac-Kuzmanović Sanja O.

2007-01-01

Full Text Available In the present study, the antifungal activity of some 1-benzylbenzimidazole derivatives against yeast Saccharomyces cerevisiae was investigated. The tested benzimidazoles displayed in vitro antifungal activity and minimum inhibitory concentration (MIC was determined for all the compounds. Quantitative structure-activity relationship (QSAR has been used to study the relationships between the antifungal activity and lipophilicity parameter, logP, calculated by using CS Chem-Office Software version 7.0. The results are discussed on the basis of statistical data. The best QSAR model for prediction of antifungal activity of the investigated series of benzimidazoles was developed. High agreement between experimental and predicted inhibitory values was obtained. The results of this study indicate that the lipophilicity parameter has a significant effect on antifungal activity of this class of compounds, which simplify design of new biologically active molecules.

Comparing Effect of 'Summarizing', 'Question-Answer Relationship', and 'Syntactic Structure Identification' on the Reading Comprehension of Iranian EFL students

Directory of Open Access Journals (Sweden)

Fatemeh Hemmati

2013-01-01

Full Text Available This study aimed at comparing the effects of 'question-answer relationship strategy', 'summarizing', and 'syntactic structure identification training'on the reading comprehension of Iranian EFL learners. The participants were sixty (34 women and 26 men intermediate students who answered an English reading comprehension test consisting of three reading passages as the pretest. During the treatment, the students in the first group were supposed to summarize the passages. The subjects in the second group familiarized with the syntactic structure identification strategy and the ones in the third group were taught the question-answer relationship strategy. At the end of the treatment, an English reading comprehension test similar to the pretest was administered to the groups as a posttest. The results suggested that there is statistically significant difference between the reading comprehension abilities of the three classes. Furthermore the use of QAR strategy led to better comprehension of reading texts with syntactic structure training and summarizing between which there was no significant difference.

Reconstructing Data Flow Diagrams from Structure Charts Based on the Input and Output Relationship

OpenAIRE

YAMAMOTO, Shuichiro

1995-01-01

The traceability of data flow diagrams against structure charts is very important for large software development. Specifying if there is a relationship between a data flow diagram and a structure chart is a time consuming task. Existing CASE tools provide a way to maintain traceability. If we can extract the input-output relationship of a system from a structure chart, the corresponding data flow diagram can be automatically generated from the relationship. For example, Benedusi et al. propos...

Integrative Genomics: Quantifying significance of phenotype-genotype relationships from multiple sources of high-throughput data

Directory of Open Access Journals (Sweden)

Eric eGamazon

2013-05-01

Full Text Available Given recent advances in the generation of high-throughput data such as whole genome genetic variation and transcriptome expression, it is critical to come up with novel methods to integrate these heterogeneous datasets and to assess the significance of identified phenotype-genotype relationships. Recent studies show that genome-wide association findings are likely to fall in loci with gene regulatory effects such as expression quantitative trait loci (eQTLs, demonstrating the utility of such integrative approaches. When genotype and gene expression data are available on the same individuals, we developed methods wherein top phenotype-associated genetic variants are prioritized if they are associated, as eQTLs, with gene expression traits that are themselves associated with the phenotype. Yet there has been no method to determine an overall p-value for the findings that arise specifically from the integrative nature of the approach. We propose a computationally feasible permutation method that accounts for the assimilative nature of the method and the correlation structure among gene expression traits and among genotypes. We apply the method to data from a study of cellular sensitivity to etoposide, one of the most widely used chemotherapeutic drugs. To our knowledge, this study is the first statistically sound quantification of the significance of the genotype-phenotype relationships resulting from applying an integrative approach. This method can be easily extended to cases in which gene expression data are replaced by other molecular phenotypes of interest, e.g., microRNA or proteomic data. This study has important implications for studies seeking to expand on genetic association studies by the use of omics data. Finally, we provide an R code to compute the empirical FDR when p-values for the observed and simulated phenotypes are available.

The Relationship between Bureaucratic School Structures and Teacher Self-Efficacy

Science.gov (United States)

Kilinç, Ali Çagatay; Kosar, Serkan; Er, Emre; Ögdem, Zeki

2016-01-01

The purpose of this study was to examine the relationship between bureaucratic school structures and teachers' self-efficacy. Participants included 252 teachers from 15 primary schools in Ankara, Turkey. Mean, standard deviation, correlation, and regression analyses were conducted. Results indicated that bureaucratic school structures and teacher…

Food structure: Its formation and relationships with other properties.

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Joardder, Mohammad U H; Kumar, Chandan; Karim, M A

2017-04-13

Food materials are complex in nature as it has heterogeneous, amorphous, hygroscopic and porous properties. During processing, microstructure of food materials changes which significantly affects other properties of food. An appropriate understanding of the microstructure of the raw food material and its evolution during processing is critical in order to understand and accurately describe dehydration processes and quality anticipation. This review critically assesses the factors that influence the modification of microstructure in the course of drying of fruits and vegetables. The effect of simultaneous heat and mass transfer on microstructure in various drying methods is investigated. Effects of changes in microstructure on other functional properties of dried foods are discussed. After an extensive review of the literature, it is found that development of food structure significantly depends on fresh food properties and process parameters. Also, modification of microstructure influences the other properties of final product. An enhanced understanding of the relationships between food microstructure, drying process parameters and final product quality will facilitate the energy efficient optimum design of the food processor in order to achieve high-quality food.

Structural Diversity and Close Interracial Relationships in College

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Bowman, Nicholas A.

2012-01-01

Recent legal and political actions have challenged the use of race-conscious college admissions policies. Earlier research offers mixed evidence about the link between an institution's racial/ethnic composition (i.e., structural diversity) and the formation of close interracial relationships, so the present study examines this topic directly for…

[The relationship between eyeball structure and visual acuity in high myopia].

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Liu, Yi-Chang; Xia, Wen-Tao; Zhu, Guang-You; Zhou, Xing-Tao; Fan, Li-Hua; Liu, Rui-Jue; Chen, Jie-Min

2010-06-01

To explore the relationship between eyeball structure and visual acuity in high myopia. Totally, 152 people (283 eyeballs) with different levels of myopia were tested for visual acuity, axial length, and fundus. All cases were classified according to diopter, axial length, and fundus. The relationships between diopter, axial length, fundus and visual acuity were studied. The mathematical models were established for visual acuity and eyeball structure markers. The visual acuity showed a moderate correlation with fundus class, comus, axial length and diopter ([r] > 0.4, P eyeball structure markers. The visual acuity should decline with axial length extension, diopter deepening and pathological deterioration of fundus. To detect the structure changes by combining different kinds of objective methods can help to assess and to judge the vision in high myopia.

Mapping the Structure-Function Relationship in Glaucoma and Healthy Patients Measured with Spectralis OCT and Humphrey Perimetry

Science.gov (United States)

Muñoz–Negrete, Francisco J.; Oblanca, Noelia; Rebolleda, Gema

2018-01-01

Purpose To study the structure-function relationship in glaucoma and healthy patients assessed with Spectralis OCT and Humphrey perimetry using new statistical approaches. Materials and Methods Eighty-five eyes were prospectively selected and divided into 2 groups: glaucoma (44) and healthy patients (41). Three different statistical approaches were carried out: (1) factor analysis of the threshold sensitivities (dB) (automated perimetry) and the macular thickness (μm) (Spectralis OCT), subsequently applying Pearson's correlation to the obtained regions, (2) nonparametric regression analysis relating the values in each pair of regions that showed significant correlation, and (3) nonparametric spatial regressions using three models designed for the purpose of this study. Results In the glaucoma group, a map that relates structural and functional damage was drawn. The strongest correlation with visual fields was observed in the peripheral nasal region of both superior and inferior hemigrids (r = 0.602 and r = 0.458, resp.). The estimated functions obtained with the nonparametric regressions provided the mean sensitivity that corresponds to each given macular thickness. These functions allowed for accurate characterization of the structure-function relationship. Conclusions Both maps and point-to-point functions obtained linking structure and function damage contribute to a better understanding of this relationship and may help in the future to improve glaucoma diagnosis. PMID:29850196

Structure/property relationships in non-linear optical materials

Energy Technology Data Exchange (ETDEWEB)

Cole, J M [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); [Durham Univ. (United Kingdom); Howard, J A.K. [Durham Univ. (United Kingdom); McIntyre, G J [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

1997-04-01

The application of neutrons to the study of structure/property relationships in organic non-linear optical materials (NLOs) is described. In particular, charge-transfer effects and intermolecular interactions are investigated. Charge-transfer effects are studied by charge-density analysis and an example of one such investigation is given. The study of intermolecular interactions concentrates on the effects of hydrogen-bonding and an example is given of two structurally similar molecules with very disparate NLO properties, as a result of different types of hydrogen-bonding. (author). 3 refs.

Investigation of the relationship between structural empowerment and organizational commitment of nurses in Zanjan hospitals.

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Eskandari, Fereidoun; Siahkali, Soheila Rabie; Shoghli, Alireza; Pazargadi, Mehrnoosh; Tafreshi, Mansoreh Zaghari

2017-03-01

The demanding nature of nursing work environments signals longstanding and growing concerns about nurses' health and job satisfaction and the provision of quality care. Specifically in health care settings, nurse leaders play an essential role in creating supportive work environments to avert these negative trends and increase nurse job satisfaction. The purpose of this study was to examine the relationship between structural empowerment and organizational commitment of nurses. 491 nurses working in Zanjan hospitals participated in this descriptive-correlational study in 2010. Tools for data collection were Meyer and Allen's organizational commitment questionnaire and "Conditions for Work Effectiveness Questionnaire-II" (CWEQ-II). Data was analyzed by SPSS16. The statistical tests such as variance analysis, t-test, pearson correlation coefficient and linear regression were used for data analysis. According to the findings, the perception of nurses working in hospitals on "Structural Empowerment" was moderate (15.98±3.29). Nurses believed "opportunity" as the most important element in structural empowerment with the score of 3.18 ±0.79. Nurses working in non-academic hospitals and in non-teaching hospitals had higher organizational commitment than others. There was a significant relationship between structural empowerment and organizational commitment. Generally, structural empowerment (relatively strong) correlates with nurses' organizational commitment. We concluded that a high structural empowerment increases the organizational commitment of nurses.

Family Structures, Relationships, and Housing Recovery Decisions after Hurricane Sandy

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Ali Nejat

2016-04-01

Full Text Available Understanding of the recovery phase of a disaster cycle is still in its infancy. Recent major disasters such as Hurricane Sandy have revealed the inability of existing policies and planning to promptly restore infrastructure, residential properties, and commercial activities in affected communities. In this setting, a thorough grasp of housing recovery decisions can lead to effective post-disaster planning by policyholders and public officials. The objective of this research is to integrate vignette and survey design to study how family bonds affected rebuilding/relocating decisions after Hurricane Sandy. Multinomial logistic regression was used to investigate respondents’ family structures before Sandy and explore whether their relationships with family members changed after Sandy. The study also explores the effect of the aforementioned relationship and its changes on households’ plans to either rebuild/repair their homes or relocate. These results were compared to another multinomial logistic regression which was applied to examine the impact of familial bonds on respondents’ suggestions to a vignette family concerning rebuilding and relocating after a hurricane similar to Sandy. Results indicate that respondents who lived with family members before Sandy were less likely to plan for relocating than those who lived alone. A more detailed examination shows that this effect was driven by those who improved their relationships with family members; those who did not improve their family relationships were not significantly different from those who lived alone, when it came to rebuilding/relocation planning. Those who improved their relationships with family members were also less likely to suggest that the vignette family relocate. This study supports the general hypothesis that family bonds reduce the desire to relocate, and provides empirical evidence that family mechanisms are important for the rebuilding/relocating decision

On the relationship between justice judgments, outcomes and identity orientations among Iranian EFL learners: A structural equation model

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Seyyed Ayatollah Razmjoo

2015-06-01

Full Text Available One problem which can be observed in the field of EFL/ESL learning is that a number of English major BA and MA students are not highly committed to their major and decide not to continue their graduate studies. Sometimes even graduate students from English majors prefer to extend their education or work in an unrelated field. This might be attributed to the extent to which they perceive evaluation procedures and outcomes as fair. Considering this, the present study investigates first the relationships between justice judgments, outcomes and identity orientations. The study, then, uses structural equation modeling in order to examine whether identity orientation has any mediating effect on the relationship between justice judgment and outcomes. Participants were74 students in Department of Foreign Languages and Linguistics, Shiraz University selected based on convenience sampling. They filled out three questionnaires on distributive and procedural justice judgments, rule compliance and outcome satisfaction, and personal and social identity orientations. The collected data was then analyzed using descriptive statistics, correlation, and structural equation modeling. Based on the obtained findings, procedural justice had significant positive correlation with rule compliance and distributive justice was significantly correlated with outcome satisfaction. The generated structural equation model also indicated that justice judgments only directly affected outcomes and identity had no mediating effect on the causal relationship between the two.

Tools to Understand Structural Property Relationships for Wood Cell Walls

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Joseph E. Jakes; Daniel J. Yelle; Charles R. Frihart

2011-01-01

Understanding structure-property relationships for wood cell walls has been hindered by the complex polymeric structures comprising these cell walls and the difficulty in assessing meaningful mechanical property measurements of individual cell walls. To help overcome these hindrances, we have developed two experimental methods: 1) two-dimensional solution state nuclear...

Significance of Operating Environment in Condition Monitoring of Large Civil Structures

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Sreenivas Alampalli

1999-01-01

Full Text Available Success of remote long-term condition monitoring of large civil structures and developing calibrated analytical models for damage detection, depend significantly on establishing accurate baseline signatures and their sensitivity. Most studies reported in the literature concentrated on the effect of structural damage on modal parameters without emphasis on reliability of modal parameters. Thus, a field bridge structure was studied for the significance of operating conditions in relation to baseline signatures. Results indicate that in practice, civil structures should be monitored for at least one full cycle of in-service environmental changes before establishing baselines for condition monitoring or calibrating finite-element models. Boundary conditions deserve special attention.

Structure-activity relationship of crustacean peptide hormones.

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Katayama, Hidekazu

2016-01-01

In crustaceans, various physiological events, such as molting, vitellogenesis, and sex differentiation, are regulated by peptide hormones. To understanding the functional sites of these hormones, many structure-activity relationship (SAR) studies have been published. In this review, the author focuses the SAR of crustacean hyperglycemic hormone-family peptides and androgenic gland hormone and describes the detailed results of our and other research groups. The future perspectives will be also discussed.

Quantitative Structure-Activity Relationships and Docking Studies of Calcitonin Gene-Related Peptide Antagonists

DEFF Research Database (Denmark)

Jenssen, Håvard; Mehrabian, Mohadeseh; Kyani, Anahita

2012-01-01

Defining the role of calcitonin gene-related peptide in migraine pathogenesis could lead to the application of calcitonin gene-related peptide antagonists as novel migraine therapeutics. In this work, quantitative structure-activity relationship modeling of biological activities of a large range...... of calcitonin gene-related peptide antagonists was performed using a panel of physicochemical descriptors. The computational studies evaluated different variable selection techniques and demonstrated shuffling stepwise multiple linear regression to be superior over genetic algorithm-multiple linear regression....... The linear quantitative structure-activity relationship model revealed better statistical parameters of cross-validation in comparison with the non-linear support vector regression technique. Implementing only five peptide descriptors into this linear quantitative structure-activity relationship model...

GirlPOWER! Strengthening Mentoring Relationships through a Structured, Gender-Specific Program

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Pryce, Julia M.; Silverthorn, Naida; Sanchez, Bernadette; DuBois, David L.

2010-01-01

The authors examine GirlPOWER! an innovative program that uses structure and group-based activities to enhance one-to-one mentoring relationships for young adolescent girls from the perspective of the focus, purpose, and authorship dimensions of mentoring relationships that Karcher and Nakkula described. The discussion draws on several sources of…

Structure-cytotoxicity relationships for dietary flavonoids

DEFF Research Database (Denmark)

Breinholt, V.; Dragsted, L.O.

1998-01-01

The cytotoxicity of a large series of dietary flavonoids was tested in a non-tumorigenic mouse and two human cancer cell lines, using the neutral red dye exclusion assay. All compounds tested exhibited a concentration-dependent cytotoxic action in the employed cell lines. The relative cytotoxicity...... of the flavonoids, however, Tvas found to vary greatly among the different cell Lines. With a few exceptions, the investigated flavonoids were more cytotoxic to the human cancer cell lines, than the mouse cell line. The differences in cytotoxicity were accounted for in part by differences in cellular uptake...... and metabolic capacity among the different cell types. In 3T3 cells fairly consistent structure-cytotoxicity relationships were found. The most cytotoxic structures tested in 3T3 cells were flavonoids with adjacent 3',4' hydroxy groups on the B-ring, such as luteolin, quercetin, myricetin, fisetin, eriodictyol...

Research on structure-alteration zone related to uranium mineralization and its exploration significance

International Nuclear Information System (INIS)

Huang Xianfang; Liu Dechang; Ye Fawang; Dong Xiuzhen; Yang Xu Zhang Hongguang

2008-01-01

The paper is focused on recommending geological characteristics of structure-alteration zone which is found from image interpretation in Bashibulake District, north of Tarim Basin, expounding remote sensing information enhancement and extraction technique, analyzing image feature, genetic mechanism and discussing the relationship between uranium mineralization and structure-alteration zone. A new discovery is raised through applying remote sensing information analysis and geologic analysis, that is, the uranium deposits in Bashibulake District are controlled by structure-alteration zone. The new understanding provides a new view point for reconsidering main controlling factors and uranium mineralization distribution in the area. It is helpful for further reconnaissance and exploration in the area. (authors)

Children's representations of multiple family relationships: organizational structure and development in early childhood.

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Schermerhorn, Alice C; Cummings, E Mark; Davies, Patrick T

2008-02-01

The authors examine mutual family influence processes at the level of children's representations of multiple family relationships, as well as the structure of those representations. From a community sample with 3 waves, each spaced 1 year apart, kindergarten-age children (105 boys and 127 girls) completed a story-stem completion task, tapping representations of multiple family relationships. Structural equation modeling with autoregressive controls indicated that representational processes involving different family relationships were interrelated over time, including links between children's representations of marital conflict and reactions to conflict, between representations of security about marital conflict and parent-child relationships, and between representations of security in father-child and mother-child relationships. Mixed support was found for notions of increasing stability in representations during this developmental period. Results are discussed in terms of notions of transactional family dynamics, including family-wide perspectives on mutual influence processes attributable to multiple family relationships.

Relationship and significance of gait deviations associated with limb length discrepancy: A systematic review.

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Khamis, Sam; Carmeli, Eli

2017-09-01

Controversy still exists as to the clinical significance of leg length discrepancy (LLD) in spite of the fact that further evidence has been emerging regarding the relationship between several clinical conditions and LLD. The objectives of our study were to review the available research with regard to LLD as a cause of clinically significant gait deviations, to determine if there is a relationship between the magnitude of LLD and the presence of gait deviations and to identify the most common gait deviations associated with LLD. In line with the PRISMA guidelines, a literature search was carried out throughout the Medline, CINAHL and EMBASE databases. Twelve articles met the predetermined inclusion criteria and were included in the review. Quality assessment using the Methodological Index for Non-Randomized Studies (MINORS) scale was completed for all included studies. Two main methodologies were found in 4 studies evaluating gait asymmetry in patients or healthy participants with anatomic LLD and 8 studies evaluating gait deviations while simulating LLD by employing artificial lifts of 1-5cm on healthy subjects. A significant relationship was found between anatomic LLD and gait deviation. Evidence suggests that gait deviations may occur with discrepancies of >1cm, with greater impact seen as the discrepancy increases. Compensatory strategies were found to occur in both the shorter and longer limb, throughout the lower limb. As the discrepancy increases, more compensatory strategies occur. Sagittal plane deviations seem to be the most effective deviations, although, frontal plane compensations also occur in the pelvis, hip and foot. Copyright © 2017 Elsevier B.V. All rights reserved.

BLAT2DOLite: An Online System for Identifying Significant Relationships between Genetic Sequences and Diseases.

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Liang Cheng

Full Text Available The significantly related diseases of sequences could play an important role in understanding the functions of these sequences. In this paper, we introduced BLAT2DOLite, an online system for annotating human genes and diseases and identifying the significant relationships between sequences and diseases. Currently, BLAT2DOLite integrates Entrez Gene database and Disease Ontology Lite (DOLite, which contain loci of gene and relationships between genes and diseases. It utilizes hypergeometric test to calculate P-values between genes and diseases of DOLite. The system can be accessed from: http://123.59.132.21:8080/BLAT2DOLite. The corresponding web service is described in: http://123.59.132.21:8080/BLAT2DOLite/BLAT2DOLiteIDMappingPort?wsdl.

A Quantitative Structure-Property Relationship (QSPR Study of Aliphatic Alcohols by the Method of Dividing the Molecular Structure into Substructure

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Bin Cheng

2011-04-01

Full Text Available A quantitative structure–property relationship (QSPR analysis of aliphatic alcohols is presented. Four physicochemical properties were studied: boiling point (BP, n-octanol–water partition coefficient (lg POW, water solubility (lg W and the chromatographic retention indices (RI on different polar stationary phases. In order to investigate the quantitative structure–property relationship of aliphatic alcohols, the molecular structure ROH is divided into two parts, R and OH to generate structural parameter. It was proposed that the property is affected by three main factors for aliphatic alcohols, alkyl group R, substituted group OH, and interaction between R and OH. On the basis of the polarizability effect index (PEI, previously developed by Cao, the novel molecular polarizability effect index (MPEI combined with odd-even index (OEI, the sum eigenvalues of bond-connecting matrix (SX1CH previously developed in our team, were used to predict the property of aliphatic alcohols. The sets of molecular descriptors were derived directly from the structure of the compounds based on graph theory. QSPR models were generated using only calculated descriptors and multiple linear regression techniques. These QSPR models showed high values of multiple correlation coefficient (R > 0.99 and Fisher-ratio statistics. The leave-one-out cross-validation demonstrated the final models to be statistically significant and reliable.

The relationship between quality management practices and organisational performance: A structural equation modelling approach

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Jamaluddin, Z.; Razali, A. M.; Mustafa, Z.

2015-02-01

The purpose of this paper is to examine the relationship between the quality management practices (QMPs) and organisational performance for the manufacturing industry in Malaysia. In this study, a QMPs and organisational performance framework is developed according to a comprehensive literature review which cover aspects of hard and soft quality factors in manufacturing process environment. A total of 11 hypotheses have been put forward to test the relationship amongst the six constructs, which are management commitment, training, process management, quality tools, continuous improvement and organisational performance. The model is analysed using Structural Equation Modeling (SEM) with AMOS software version 18.0 using Maximum Likelihood (ML) estimation. A total of 480 questionnaires were distributed, and 210 questionnaires were valid for analysis. The results of the modeling analysis using ML estimation indicate that the fits statistics of QMPs and organisational performance model for manufacturing industry is admissible. From the results, it found that the management commitment have significant impact on the training and process management. Similarly, the training had significant effect to the quality tools, process management and continuous improvement. Furthermore, the quality tools have significant influence on the process management and continuous improvement. Likewise, the process management also has a significant impact to the continuous improvement. In addition the continuous improvement has significant influence the organisational performance. However, the results of the study also found that there is no significant relationship between management commitment and quality tools, and between the management commitment and continuous improvement. The results of the study can be used by managers to prioritize the implementation of QMPs. For instances, those practices that are found to have positive impact on organisational performance can be recommended to

Connecting Structure-Property and Structure-Function Relationships across the Disciplines of Chemistry and Biology: Exploring Student Perceptions

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Kohn, Kathryn P.; Underwood, Sonia M.; Cooper, Melanie M.

2018-01-01

While many university students take science courses in multiple disciplines, little is known about how they perceive common concepts from different disciplinary perspectives. Structure-property and structure-function relationships have long been considered important explanatory concepts in the disciplines of chemistry and biology, respectively.…

Familial identification: population structure and relationship distinguishability.

Science.gov (United States)

Rohlfs, Rori V; Fullerton, Stephanie Malia; Weir, Bruce S

2012-02-01

With the expansion of offender/arrestee DNA profile databases, genetic forensic identification has become commonplace in the United States criminal justice system. Implementation of familial searching has been proposed to extend forensic identification to family members of individuals with profiles in offender/arrestee DNA databases. In familial searching, a partial genetic profile match between a database entrant and a crime scene sample is used to implicate genetic relatives of the database entrant as potential sources of the crime scene sample. In addition to concerns regarding civil liberties, familial searching poses unanswered statistical questions. In this study, we define confidence intervals on estimated likelihood ratios for familial identification. Using these confidence intervals, we consider familial searching in a structured population. We show that relatives and unrelated individuals from population samples with lower gene diversity over the loci considered are less distinguishable. We also consider cases where the most appropriate population sample for individuals considered is unknown. We find that as a less appropriate population sample, and thus allele frequency distribution, is assumed, relatives and unrelated individuals become more difficult to distinguish. In addition, we show that relationship distinguishability increases with the number of markers considered, but decreases for more distant genetic familial relationships. All of these results indicate that caution is warranted in the application of familial searching in structured populations, such as in the United States.

Familial identification: population structure and relationship distinguishability.

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Rori V Rohlfs

2012-02-01

Full Text Available With the expansion of offender/arrestee DNA profile databases, genetic forensic identification has become commonplace in the United States criminal justice system. Implementation of familial searching has been proposed to extend forensic identification to family members of individuals with profiles in offender/arrestee DNA databases. In familial searching, a partial genetic profile match between a database entrant and a crime scene sample is used to implicate genetic relatives of the database entrant as potential sources of the crime scene sample. In addition to concerns regarding civil liberties, familial searching poses unanswered statistical questions. In this study, we define confidence intervals on estimated likelihood ratios for familial identification. Using these confidence intervals, we consider familial searching in a structured population. We show that relatives and unrelated individuals from population samples with lower gene diversity over the loci considered are less distinguishable. We also consider cases where the most appropriate population sample for individuals considered is unknown. We find that as a less appropriate population sample, and thus allele frequency distribution, is assumed, relatives and unrelated individuals become more difficult to distinguish. In addition, we show that relationship distinguishability increases with the number of markers considered, but decreases for more distant genetic familial relationships. All of these results indicate that caution is warranted in the application of familial searching in structured populations, such as in the United States.

A validation of the Experiences in Close Relationships-Relationship Structures scale (ECR-RS) in adolescents

DEFF Research Database (Denmark)

Donbaek, Dagmar Feddern; Elklit, Ask

2014-01-01

structures in adults and, hence, moves beyond the traditional focus on romantic relationships. The present article explored the psychometric abilities of the ECR-RS across parental and best friend domains in a sample of 15 to 18-year-olds (n = 1999). Two oblique factors were revealed across domains...

Structural relationships and vasorelaxant activity of monoterpenes

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Cardoso Lima Tamires

2012-09-01

Full Text Available Abstract Background and purpose of the study The hypotensive activity of the essential oil of Mentha x villosa and its main constituent, the monoterpene rotundifolone, have been reported. Therefore, our objective was to evaluate the vasorelaxant effect of monoterpenes found in medicinal plants and establish the structure-activity relationship of rotundifolone and its structural analogues on the rat superior mesenteric artery. Methods Contractions of the vessels were induced with 10 μM of phenylephine (Phe in rings with endothelium. During the tonic phase of the contraction, the monoterpenes (10-8 - 10-3, cumulatively were added to the organ bath. The extent of relaxation was expressed as the percentage of Phe-induced contraction. Results The results from the present study showed that both oxygenated terpenes (rotundifolone, (+-limonene epoxide, pulegone epoxide, carvone epoxide, and (+-pulegone and non-oxygenated terpene ((+-limonene exhibit relaxation activity. The absence of an oxygenated molecular structure was not a critical requirement for the molecule to be bioactive. Also it was found that the position of ketone and epoxide groups in the monoterpene structures influence the vasorelaxant potency and efficacy. Major conclusion The results suggest that the presence of functional groups in the chemical structure of rotundifolone is not essential for its vasorelaxant activity.

The Moderating Role of Corporate Governance on the Relationship between Capital Structure and Financial Performance: Evidence from Manufacturing Sector of Pakistan

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Muhammad Iqbal

2017-02-01

Full Text Available The key purpose of this research paper is to explore the moderating effect of Corporate Governance on the relationship between accounting base financial performance i.e. ROA, and ROE and Capital Structure of 173 Manufacturing firms listed in KSE of Pakistan for the period of 2009 to 2014. In this study multiple regression method is used under fixed effect regression model approach on panel data. The empirical results show that the inclusion of Corporate Governance Index (CGI as moderating variable has influenced the interaction between Capital Structure and Financial Performance which was positively significant. The result is generally found that the most of Pakistani manufacturing listed firms pursue good corporate governance mechanism and use good and optimal level of Capital Mix to get the better and high financial performance. Furthermore, the corporate governance sub-indices i.e. board structure (BOD-I and transparency & disclosure (DISC-III both also have positive and statistically significant association with both firms performance variables: ROA and ROE. Moreover, the ownership structure sub-index (OWS-II has not significant influence on financial performance. In last, the capital structure also has positive relationship with financial performance, interestingly about 70 per cent of Capital is financed by Equity capital and the Debt capital signifies 30 per cent only. The core significance of this paper is to investigate the impact of Corporate Governance practices on financial decisions from the Pakistani perspective.

Computational study of the structure-free radical scavenging relationship of procyanidins.

Science.gov (United States)

Mendoza-Wilson, Ana María; Castro-Arredondo, Sergio Ivan; Balandrán-Quintana, René Renato

2014-10-15

Procyanidins (PCs) are effective free radical scavengers, however, their antioxidant ability is variable because they have different degrees of polymerisation, are composed by distinct types of subunits and are very susceptible to changes in conformation. In this work the structure-free radical scavenging relationship of monomers, dimers and trimers of PCs was studied through the hydrogen atom transfer (HAT), sequential proton-loss electron-transfer (SPLET) and single electron transfer followed by proton transfer (SET-PT) mechanisms in aqueous phase, employing the Density Functional Theory (DFT) computational method. The structure-free radical scavenging relationship of PCs showed a very similar behaviour in HAT and SET-PT mechanisms, but very different in the SPLET mechanism. The structural factor that showed more effects on the ability of PCs to scavenge free radicals in aqueous phase was the conformation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quantitative structure-property relationship (correlation analysis) of phosphonic acid-based chelates in design of MRI contrast agent.

Science.gov (United States)

Tiwari, Anjani K; Ojha, Himanshu; Kaul, Ankur; Dutta, Anupama; Srivastava, Pooja; Shukla, Gauri; Srivastava, Rakesh; Mishra, Anil K

2009-07-01

Nuclear magnetic resonance imaging is a very useful tool in modern medical diagnostics, especially when gadolinium (III)-based contrast agents are administered to the patient with the aim of increasing the image contrast between normal and diseased tissues. With the use of soft modelling techniques such as quantitative structure-activity relationship/quantitative structure-property relationship after a suitable description of their molecular structure, we have studied a series of phosphonic acid for designing new MRI contrast agent. Quantitative structure-property relationship studies with multiple linear regression analysis were applied to find correlation between different calculated molecular descriptors of the phosphonic acid-based chelating agent and their stability constants. The final quantitative structure-property relationship mathematical models were found as--quantitative structure-property relationship Model for phosphonic acid series (Model 1)--log K(ML) = {5.00243(+/-0.7102)}- MR {0.0263(+/-0.540)}n = 12 l r l = 0.942 s = 0.183 F = 99.165 quantitative structure-property relationship Model for phosphonic acid series (Model 2)--log K(ML) = {5.06280(+/-0.3418)}- MR {0.0252(+/- .198)}n = 12 l r l = 0.956 s = 0.186 F = 99.256.

Structure-Property Relationship in High Tg Thermosetting Polyimides

Science.gov (United States)

Chuang, Kathy C.; Meador, Mary Ann B.; HardyGreen, DeNise

2000-01-01

This viewgraph presentation gives an overview of the structure-property relationship in high glass transition temperatures (T(sub g)) thermosetting polyimides. The objectives of this work are to replace MDA in PMR-15 with 2,2-substituted benzidine and to evaluate the thermo-oxidative stability and mechanical properties of DMBZ-15 against PMR-15. Details are given on the T(sub g) of polyimide resins, the x-ray crystal structure of 2,2-Bis(trifluoro)benzidine (BFBZ), the isothermal aging of polyimide resins at 288 C under 1 atm of circulating air, the compressive strength of polyimide composites, and a gas evaluation profile of DMBZ-15 polyimide resins.

Structural and reliability analysis of quality of relationship index in cancer patients.

Science.gov (United States)

Cousson-Gélie, Florence; de Chalvron, Stéphanie; Zozaya, Carole; Lafaye, Anaïs

2013-01-01

Among psychosocial factors affecting emotional adjustment and quality of life, social support is one of the most important and widely studied in cancer patients, but little is known about the perception of support in specific significant relationships in patients with cancer. This study examined the psychometric properties of the Quality of Relationship Inventory (QRI) by evaluating its factor structure and its convergent and discriminant validity in a sample of cancer patients. A total of 388 patients completed the QRI. Convergent validity was evaluated by testing the correlations between the QRI subscales and measures of general social support, anxiety and depression symptoms. Discriminant validity was examined by testing group comparison. The QRI's longitudinal invariance across time was also tested. Principal axis factor analysis with promax rotation identified three factors accounting for 42.99% of variance: perceived social support, depth, and interpersonal conflict. Estimates of reliability with McDonald's ω coefficient were satisfactory for all the QRI subscales (ω ranging from 0.75 - 0.85). Satisfaction from general social support was negatively correlated with the interpersonal conflict subscale and positively with the depth subscale. The interpersonal conflict and social support scales were correlated with depression and anxiety scores. We also found a relative stability of QRI subscales (measured 3 months after the first evaluation) and differences between partner status and gender groups. The Quality of Relationship Inventory is a valid tool for assessing the quality of social support in a particular relationship with cancer patients.

Structural equation modeling assessing relationship between mathematics beliefs, teachers' attitudes and teaching practices among novice teachers in Malaysia

Science.gov (United States)

Borhan, Noziati; Zakaria, Effandi

2017-05-01

This quantitative study was conducted to investigate the perception level of novice teachers about mathematics belief, teachers' attitude towards mathematics and teaching practices of mathematics in the classroom. In addition, it also aims to identify whether there is a correspondence model with the data obtained and to identify the relationship between the variables of beliefs, attitudes and practices among novice teachers in Malaysia. A total of 263 primary novice teachers throughout the country were involved in this study were selected randomly. Respondents are required to provide a response to the questionnaire of 66 items related to mathematics beliefs, attitudes and practices of the teaching mathematics. There are ten sub-factors which have been established in this instrument for three major constructs using a Likert scale rating of five points. The items of the constructs undergo the exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) procedure involve of unidimensionality test, convergent validity, construct validity and discriminant validity. Descriptive statistics were used to describe the frequency, percentage, the mean and standard deviation for completing some research questions that have been expressed. As for inferential statistical analysis, the researchers used structural equation modeling (SEM) to answer the question of correspondents model and the relationship between these three variables. The results of the study were found that there exist a correspondence measurement and structural model with the data obtained. While the relationship between variable found that mathematics beliefs have a significant influence on teachers' attitudes towards mathematics as well as the relationship between the attitudes with teaching practices. Meanwhile, mathematics belief had no significant relationship with mathematics teaching practices among novice teachers in Malaysia.

Impact velocity vs. target hardness relationships for equivalent response of cask structures

International Nuclear Information System (INIS)

Chen, T.F.; Chen, J.C.; Witte, M.C.; Fischer, L.E.

1993-01-01

In this paper, impact velocity vs. target hardness relationships for cask structures are reviewed. The relationships are based on equivalent cask responses in terms of equal deceleration or similar cask damages. By examining several past cask or container tests as well as some analytical results, some conclusions can be drawn about the relationship between target hardness and equivalent impact velocities. This relationship clearly shows that the cask response to impact is cask-dependent and that the rigid sphere impact model results in an unconservative estimate of equivalent velocity

Physiological significance of Fuc and Sialic acid containing glycans in the body

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Muhammad Ramzan Manwar Hussain

2016-09-01

Full Text Available Complex biomolecular machinery carrying diverse glycan chains are involved in a wide range of physiological activities including blood group determination, cancer recognition protein stabilization and sperm–egg interaction. Diversity of glycan chains, linked to lipids and proteins is due to isomeric and conformational modifications of various sugar residues, giving rise to unique carbohydrate structures with a wide range of anomeric linkages. This unique and significant structural diversity of naturally occurring oligosaccharide structures make them the best recognition markers for countless physiological activities. This is a challenging task to explore the relationship between biological processes and stereochemical behavior of sugar residues. Current review article is related with the physiological significance of glycans carrying fucose and/or sialic residues in complex biomolecular assemblies. Both the sugar units have a diverse range of anomery and linkages with the penultimate sugars. The existing literature and databases did not contain comprehensive information regarding structure–function relationship of glycans. Therefore, the current study is scheduled to debate on the structure–function relationship of glycans carrying Fuc and sialic acid in their backbone structures.

3-alkyl fentanyl analogues: Structure-activity-relationship study

OpenAIRE

Vučković, Sonja; Savić-Vujović, Katarina; Srebro, Dragana; Ivanović, Milovan; Došen-Mićović, Ljiljana; Stojanović, Radan; Prostran, Milica

2012-01-01

Introduction. Fentanyl belongs to 4-anilidopiperidine class of synthetic opioid analgesics. It is characterized by high potency, rapid onset and short duration of action. A large number of fentanyl analogues have been synthesized so far, both to establish the structure-activity-relationship (SAR) and to find novel, clinically useful analgesic drugs. Objective. In this study, newly synthesized 3-alkyl fentanyl analogues were examined for analgesic activity and compared with fentanyl. Methods. ...

Synthesis and anticancer structure activity relationship investigation of cationic anthraquinone analogs.

Science.gov (United States)

Shrestha, Jaya P; Fosso, Marina Y; Bearss, Jeremiah; Chang, Cheng-Wei Tom

2014-04-22

We have synthesized a series of novel 4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d][1,2,3]triazol-3-ium salts, which can be viewed as analogs of cationic anthraquinones. Unlike the similar analogs that we have reported previously, these compounds show relatively weak antibacterial activities but exert strong anticancer activities (low μM to nM GI50), in particular, against melanoma, colon cancer, non-small cell lung cancer and central nervous system (CNS) cancer. These compounds are structurally different from their predecessors by having the aromatic group, instead of alkyl chains, directly attached to the cationic anthraquinone scaffold. Further investigation in the structure-activity relationship (SAR) reveals the significant role of electron donating substituents on the aromatic ring in enhancing the anticancer activities via resonance effect. Steric hindrance of these groups is disadvantageous but is less influential than the resonance effect. The difference in the attached groups at N-1 position of the cationic anthraquinone analog is the main structural factor for the switching of biological activity from antibacterial to anticancer. The discovery of these compounds may lead to the development of novel cancer chemotherapeutics. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Examining Relationships among Enabling School Structures, Academic Optimism and Organizational Citizenship Behaviors

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Messick, Penelope Pope

2012-01-01

This study examined the relationships among enabling school structures, academic optimism, and organizational citizenship behaviors. Additionally, it sought to determine if academic optimism served as a mediator between enabling school structures and organizational citizenship behaviors. Three existing survey instruments, previously tested for…

Structure Matters: The Role of Clique Hierarchy in the Relationship Between Adolescent Social Status and Aggression and Prosociality.

Science.gov (United States)

Pattiselanno, Kim; Dijkstra, Jan Kornelis; Steglich, Christian; Vollebergh, Wilma; Veenstra, René

2015-12-01

Peer cliques form an important context for the social development of adolescents. Although clique members are often similar in social status, also within cliques, status differences exist. How differences in social status between clique members are related to behaviors of its individual members is rather unknown. This study examined to what extent the relationship of individual social status (i.e., perceived popularity) with aggression and prosocial behavior depends on the level of internal clique hierarchy. The sample consists of 2674 adolescents (49.8% boys), with a mean age of 14.02. We focused specifically on physical and relational aggression, and practical and emotional support, because these behaviors have shown to be of great importance for social relationships and social standing among adolescents. The internal status hierarchy of cliques was based on the variation in individual social status between clique members (i.e., clique hierarchization) and the structure of status scores within a clique (pyramid shape, inverted pyramid, or equal distribution of social status scores) (i.e., clique status structure). The results showed that differences in aggressive and prosocial behaviors were particularly moderated by clique status structure: aggression was stronger related to individual social status in (girls') cliques where the clique status structure reflected an inverted pyramid with relatively more high status adolescents within the clique than low status peers, and prosocial behavior showed a significant relationship with individual social status, again predominantly in inverted pyramid structured (boys' and girls') cliques. Furthermore, these effects differed by types of gender cliques: the associations were found in same gender but not mixed-gender cliques. The findings stress the importance of taking into account internal clique characteristics when studying adolescent social status in relationship to aggression and prosociality.

On-rate based optimization of structure-kinetic relationship--surfing the kinetic map.

Science.gov (United States)

Schoop, Andreas; Dey, Fabian

2015-10-01

In the lead discovery process residence time has become an important parameter for the identification and characterization of the most efficacious compounds in vivo. To enable the success of compound optimization by medicinal chemistry toward a desired residence time the understanding of structure-kinetic relationship (SKR) is essential. This article reviews various approaches to monitor SKR and suggests using the on-rate as the key monitoring parameter. The literature is reviewed and examples of compound series with low variability as well as with significant changes in on-rates are highlighted. Furthermore, findings of kinetic on-rate changes are presented and potential underlying rationales are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Structure/property relationships in multipass GMA welding of beryllium.

Energy Technology Data Exchange (ETDEWEB)

Hochanadel, P. W. (Patrick W.); Hults, W. L. (William L.); Thoma, D. J. (Dan J.); Dave, V. R. (Vivek R.); Kelly, A. M. (Anna Marie); Pappin, P. A. (Pallas A.); Cola, M. J. (Mark J.); Burgardt, P. (Paul)

2001-01-01

Beryllium is an interesting metal that has a strength to weight ratio six times that of steel. Because of its unique mechanical properties, beryllium is used in aerospace applications such as satellites. In addition, beryllium is also used in x-ray windows because it is nearly transparent to x-rays. Joining of beryllium has been studied for decades (Ref.l). Typically joining processes include braze-welding (either with gas tungsten arc or gas metal arc), soldering, brazing, and electron beam welding. Cracking which resulted from electron beam welding was recently studied to provide structure/property relationships in autogenous welds (Ref. 2). Braze-welding utilizes a welding arc to melt filler, and only a small amount of base metal is melted and incorporated into the weld pool. Very little has been done to characterize the braze-weld in terms of the structure/property relationships, especially with reference to multipass welding. Thus, this investigation was undertaken to evaluate the effects of multiple passes on microstructure, weld metal composition, and resulting material properties for beryllium welded with aluminum-silicon filler metal.

Significance of structure–soil–structure interaction for closely spaced structures

International Nuclear Information System (INIS)

Roy, Christine; Bolourchi, Said; Eggers, Daniel

2015-01-01

Nuclear facilities typically consist of many closely spaced structures with different sizes and depths of embedment. Seismic response of each structure could be influenced by dynamic structure–soil–structure interaction (SSSI) behavior of adjacent closely spaced structures. This paper examines the impact of SSSI on the in-structure response spectra (ISRS) and peak accelerations of a light structure adjacent to a heavy structure and of a heavy structure adjacent to a similar heavy structure for several soil cases, foundation embedment depths, and separation distances. The impacts of a heavy surface or embedded structure on adjacent ground motions were studied. The analyses demonstrated the adjacent ground motions are sensitive to foundation embedment, soil profile, response frequency, and distance from the structure. Seismic responses of a light structure located near a heavy structure are calculated either by modeling both structures subjected to free field motions, or performing a cascade analysis by considering the light structure model subjected to modified ground motions due to the heavy structure. Cascade SSSI analyses are shown to adequately account for the effect of the heavy structure on the light structure without explicitly modeling both structures together in a single analysis. To further study the influence of SSSI behavior, this paper examines dynamic response of two adjacent heavy structures and compares this response to response of a single heavy structure neglecting adjacent structures. The SSSI responses of the two heavy structures are evaluated for varying soil conditions and structure separation distances using three-dimensional linear SSI analyses and considering anti-symmetry boundary conditions. The analyses demonstrate that the SSSI response of a light or a heavy structure can be influenced by the presence of a nearby heavy structure. Although this study considers linear analysis methodology, the conclusion of SSSI influences on dynamic

A study on the relationship between capital structure and the performance of production market: A case study of firms listed on Tehran Stock Exchange

Directory of Open Access Journals (Sweden)

Kobra Sadat Salek Esfahani

2013-04-01

Full Text Available One of the most complicated and challenging issues in today's financial managers is the relationship between the components of capital structure in terms of bonds and shares used for financing and share price of their company, and its effects on the macroeconomic variables. This research aims to study the relationship between the capital structure and performance of the production market in some firms listed on Tehran Stock Exchange (TSE. In this research, the index of capital structure is debt ratio and that of production market performance is sales growth and return of assets (ROA. The statistical sample of this research includes 128 companies, which have been active in 11 various industries and listed on TSE over the period 2005-2010. The statistical techniques used to test the hypotheses of this research include correlation coefficient and pooled least squares regression (panel data. Based on the results of our survey, there is a strong and significant relationship between debt ratio and return on assets among the companies listed on TSE and most industries especially based metals at the confidence level of 95%. In contrast, there is no strong and significant relationship between debt ratio and sales growth in the above-mentioned companies and in most industries.

Quantitative structure-activity relationships for green algae growth inhibition by polymer particles.

NARCIS (Netherlands)

Nolte, Tom M; Peijnenburg, Willie J G M; Hendriks, A Jan; van de Meent, Dik

After use and disposal of chemical products, many types of polymer particles end up in the aquatic environment with potential toxic effects to primary producers like green algae. In this study, we have developed Quantitative Structure-Activity Relationships (QSARs) for a set of highly structural

Significance of Shear Wall in Multi-Storey Structure With Seismic Analysis

Science.gov (United States)

Bongilwar, Rajat; Harne, V. R.; Chopade, Aditya

2018-03-01

In past decades, shear walls are one of the most appropriate and important structural component in multi-storied building. Therefore, it would be very interesting to study the structural response and their systems in multi-storied structure. Shear walls contribute the stiffness and strength during earthquakes which are often neglected during design of structure and construction. This study shows the effect of shear walls which significantly affect the vulnerability of structures. In order to test this hypothesis, G+8 storey building was considered with and without shear walls and analyzed for various parameters like base shear, storey drift ratio, lateral displacement, bending moment and shear force. Significance of shear wall has been studied with the help of two models. First model is without shear wall i.e. bare frame and other another model is with shear wall considering opening also in it. For modeling and analysis of both the models, FEM based software ETABS 2016 were used. The analysis of all models was done using Equivalent static method. The comparison of results has been done based on same parameters like base shear, storey drift ratio, lateral displacement, bending moment and shear force.

Sequence-structure relationships in RNA loops: establishing the basis for loop homology modeling.

Science.gov (United States)

Schudoma, Christian; May, Patrick; Nikiforova, Viktoria; Walther, Dirk

2010-01-01

The specific function of RNA molecules frequently resides in their seemingly unstructured loop regions. We performed a systematic analysis of RNA loops extracted from experimentally determined three-dimensional structures of RNA molecules. A comprehensive loop-structure data set was created and organized into distinct clusters based on structural and sequence similarity. We detected clear evidence of the hallmark of homology present in the sequence-structure relationships in loops. Loops differing by structures. Thus, our results support the application of homology modeling for RNA loop model building. We established a threshold that may guide the sequence divergence-based selection of template structures for RNA loop homology modeling. Of all possible sequences that are, under the assumption of isosteric relationships, theoretically compatible with actual sequences observed in RNA structures, only a small fraction is contained in the Rfam database of RNA sequences and classes implying that the actual RNA loop space may consist of a limited number of unique loop structures and conserved sequences. The loop-structure data sets are made available via an online database, RLooM. RLooM also offers functionalities for the modeling of RNA loop structures in support of RNA engineering and design efforts.

Processing information about support exchanges in close relationships: The role of a knowledge structure

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Bulent eTuran

2016-02-01

Full Text Available People develop knowledge of interpersonal interaction patterns (e.g., prototypes and schemas, which shape how they process incoming information. One such knowledge structure based on attachment theory was examined: the secure base script (the prototypic sequence of events when an attachment figure comforts a close relationship partner in distress. In two studies (N = 53 and N = 119, participants were shown animated film clips in which geometric figures depicted the secure base script and asked to describe the animations. Both studies found that many people readily recognize the secure-base script from these minimal cues quite well, suggesting that this script is not only available in the context of specific relationships (i.e., a relationship-specific knowledge: The generalized (abstract structure of the script is also readily accessible, which would make it possible to apply it to any relationship (including new relationships. Regression analyses suggested that participants who recognized the script were more likely to (a include more animation elements when describing the animations, (b see a common theme in different animations, (c create better organized stories, and (d later recall more details of the animations. These findings suggest that access to this knowledge structure helps a person organize and remember relevant incoming information. Furthermore, in both Study 1 and Study 2, individual differences in the ready recognition of the script were associated with individual differences in having access to another related knowledge: indicators suggesting that a potential relationship partner can be trusted to be supportive and responsive at times of stress. Results of Study 2 also suggest that recognizing the script is associated with those items of an attachment measure that concern giving and receiving support. Thus, these knowledge structures may shape how people process support-relevant information in their everyday lives, potentially

Relationship between Structural and Stress Relaxation in a Block-Copolymer Melt

International Nuclear Information System (INIS)

Patel, Amish J.; Narayanan, Suresh; Sandy, Alec; Mochrie, Simon G. J.; Garetz, Bruce A.; Watanabe, Hiroshi; Balsara, Nitash P.

2006-01-01

The relationship between structural relaxation on molecular length scales and macroscopic stress relaxation was explored in a disordered block-copolymer melt. Experiments show that the structural relaxation time, measured by x-ray photon correlation spectroscopy is larger than the terminal stress relaxation time, measured by rheology, by factors as large as 100. We demonstrate that the structural relaxation data are dominated by the diffusion of intact micelles while the stress relaxation data are dominated by contributions due to disordered concentration fluctuations

Quantitative structure-retention relationship studies using immobilized artificial membrane chromatography I: amended linear solvation energy relationships with the introduction of a molecular electronic factor.

Science.gov (United States)

Li, Jie; Sun, Jin; Cui, Shengmiao; He, Zhonggui

2006-11-03

Linear solvation energy relationships (LSERs) amended by the introduction of a molecular electronic factor were employed to establish quantitative structure-retention relationships using immobilized artificial membrane (IAM) chromatography, in particular ionizable solutes. The chromatographic indices, log k(IAM), were determined by HPLC on an IAM.PC.DD2 column for 53 structurally diverse compounds, including neutral, acidic and basic compounds. Unlike neutral compounds, the IAM chromatographic retention of ionizable compounds was affected by their molecular charge state. When the mean net charge per molecule (delta) was introduced into the amended LSER as the sixth variable, the LSER regression coefficient was significantly improved for the test set including ionizable solutes. The delta coefficients of acidic and basic compounds were quite different indicating that the molecular electronic factor had a markedly different impact on the retention of acidic and basic compounds on IAM column. Ionization of acidic compounds containing a carboxylic group tended to impair their retention on IAM, while the ionization of basic compounds did not have such a marked effect. In addition, the extra-interaction with the polar head of phospholipids might cause a certain change in the retention of basic compounds. A comparison of calculated and experimental retention indices suggested that the semi-empirical LSER amended by the addition of a molecular electronic factor was able to reproduce adequately the experimental retention factors of the structurally diverse solutes investigated.

Social relationship difficulties in autism and reactive attachment disorder: Improving diagnostic validity through structured assessment.

Science.gov (United States)

Davidson, Claire; O'Hare, Anne; Mactaggart, Fiona; Green, Jonathan; Young, David; Gillberg, Christopher; Minnis, Helen

2015-05-01

Autism Spectrum Disorder (ASD) versus Reactive Attachment Disorder (RAD) is a common diagnostic challenge for clinicians due to overlapping difficulties with social relationships. RAD is associated with neglect or maltreatment whereas ASD is not: accurate differential diagnosis is therefore critical. Very little research has investigated the relationship between the two, and it is unknown if standardised measures are able to discriminate between ASD and RAD. The current study aimed to address these issues. Fifty eight children with ASD, and no history of maltreatment, were group matched on age with 67 children with RAD. Group profiles on multi-informant measures of RAD were investigated and group differences explored. Discriminant function analysis determined assessment features that best discriminated between the two groups. Although, according to parent report, children with ASD presented with significantly fewer indiscriminate friendliness behaviours compared to the RAD group (p<0.001), 36 children with ASD appeared to meet core RAD criteria. However, structured observation clearly demonstrated that features were indicative of ASD and not RAD for all but 1 of these 36 children. Children with RAD and children with ASD may demonstrate similar social relationship difficulties but there appears to be a difference in the social quality of the interactions between the groups. In most cases it was possible to differentiate between children with ASD and children with RAD via structured observation. Nevertheless, for a small proportion of children with ASD, particularly those whose difficulties may be more subtle, our current standardised measures, including structured observation, may not be effective in differentiating RAD from ASD. Copyright © 2015. Published by Elsevier Ltd.

MEDITERRANEAN FOREST TREE DECLINE IN ITALY: RELATIONSHIPS BETWEEN DROUGHT, POLLUTANTS AND THE WAX STRUCTURE OF LEAVES

Directory of Open Access Journals (Sweden)

E. PAOLETTI

1996-04-01

Full Text Available After presenting the situation of forest decline in Italy and analyzing the factors that play a contributing role, tbis paper studies the response of the epicuticular wax structures and the stomata in ten broadleaf species and one conifer to fog-like treatments with acids andlor surfactants and to severe water stress. The main results are that wax structure alterations vary in intensity in the different species studied and that the microstructural alterations observed in field conditions cannot be attributed only to severe drought. since sample trccs put through water stress simulations do nol differ significantly from controls. In the artificial surfactant treatment, a positive relationship between structural damage to tbe stomata and transpiration suggests possible synergies between the effects of drought and those of pollutants in inducing stress conditions in Mediterranean vegetation.

Stress Exposure in Significant Relationships Is Associated with Lymph Node Status in Breast Cancer.

Directory of Open Access Journals (Sweden)

Chiara Renzi

Full Text Available Life stress exposure may impact on health and disease. Previous literature showed that stressful life events are associated with cancer incidence, survival and mortality. In animal models, patterns of maternal care have been shown to critically affect stress sensitivity and immunity trajectories later in life, by modifying DNA methylation during critical periods early in life. However, the role of parental care in breast cancer progression and survival has only limitedly been explored. Here, we investigated whether these factors may be linked to biological prognostic variables.One hundred twenty-three women hospitalized for surgery of primary breast cancer completed a questionnaire assessing parental bonding. Stressful events throughout the life span were also assessed.We found that the absence of optimal parental relationships is significantly associated with an increased risk of lymph node involvement, adjusting for confounders, while cumulative stress in the area of sentimental relationships is borderline significantly associated with the same prognostic factor.Our results suggest that parental bonding and sentimental relations may have a role in breast cancer progression. These variables represent an important evolutionary aspect which may modulate cancer progression through psycho-physiological stress pathways and influence the immune system.

Pathways to Structure-Property Relationships of Peptide-Materials Interfaces: Challenges in Predicting Molecular Structures.

Science.gov (United States)

Walsh, Tiffany R

2017-07-18

An in-depth appreciation of how to manipulate the molecular-level recognition between peptides and aqueous materials interfaces, including nanoparticles, will advance technologies based on self-organized metamaterials for photonics and plasmonics, biosensing, catalysis, energy generation and harvesting, and nanomedicine. Exploitation of the materials-selective binding of biomolecules is pivotal to success in these areas and may be particularly key to producing new hierarchically structured biobased materials. These applications could be accomplished by realizing preferential adsorption of a given biomolecule onto one materials composition over another, one surface facet over another, or one crystalline polymorph over another. Deeper knowledge of the aqueous abiotic-biotic interface, to establish clear structure-property relationships in these systems, is needed to meet this goal. In particular, a thorough structural characterization of the surface-adsorbed peptides is essential for establishing these relationships but can often be challenging to accomplish via experimental approaches alone. In addition to myriad existing challenges associated with determining the detailed molecular structure of any molecule adsorbed at an aqueous interface, experimental characterization of materials-binding peptides brings new, complex challenges because many materials-binding peptides are thought to be intrinsically disordered. This means that these peptides are not amenable to experimental techniques that rely on the presence of well-defined secondary structure in the peptide when in the adsorbed state. To address this challenge, and in partnership with experiment, molecular simulations at the atomistic level can bring complementary and critical insights into the origins of this abiotic/biotic recognition and suggest routes for manipulating this phenomenon to realize new types of hybrid materials. For the reasons outlined above, molecular simulation approaches also face

Quantitative structure-activity relationships of selective antagonists of glucagon receptor using QuaSAR descriptors.

Science.gov (United States)

Manoj Kumar, Palanivelu; Karthikeyan, Chandrabose; Hari Narayana Moorthy, Narayana Subbiah; Trivedi, Piyush

2006-11-01

In the present paper, quantitative structure activity relationship (QSAR) approach was applied to understand the affinity and selectivity of a novel series of triaryl imidazole derivatives towards glucagon receptor. Statistically significant and highly predictive QSARs were derived for glucagon receptor inhibition by triaryl imidazoles using QuaSAR descriptors of molecular operating environment (MOE) employing computer-assisted multiple regression procedure. The generated QSAR models revealed that factors related to hydrophobicity, molecular shape and geometry predominantly influences glucagon receptor binding affinity of the triaryl imidazoles indicating the relevance of shape specific steric interactions between the molecule and the receptor. Further, QSAR models formulated for selective inhibition of glucagon receptor over p38 mitogen activated protein (MAP) kinase of the compounds in the series highlights that the same structural features, which influence the glucagon receptor affinity, also contribute to their selective inhibition.

Biosynthesis and structure-activity relationships of the lipid a family of glycolipids.

Science.gov (United States)

Xiao, Xirui; Sankaranarayanan, Karthik; Khosla, Chaitan

2017-10-01

Lipopolysaccharide (LPS), a glycolipid found in the outer membrane of Gram-negative bacteria, is a potent elicitor of innate immune responses in mammals. A typical LPS molecule is composed of three different structural domains: a polysaccharide called the O-antigen, a core oligosaccharide, and Lipid A. Lipid A is the amphipathic glycolipid moiety of LPS. It stimulates the immune system by tightly binding to Toll-like receptor 4. More recently, Lipid A has also been shown to activate intracellular caspase-4 and caspase-5. An impressive diversity is observed in Lipid A structures from different Gram-negative bacteria, and it is well established that subtle changes in chemical structure can result in dramatically different immune activities. For example, Lipid A from Escherichia coli is highly toxic to humans, whereas a biosynthetic precursor called Lipid IV A blocks this toxic activity, and monophosphoryl Lipid A from Salmonella minnesota is a vaccine adjuvant. Thus, an understanding of structure-activity relationships in this glycolipid family could be used to design useful immunomodulatory agents. Here we review the biosynthesis, modification, and structure-activity relationships of Lipid A. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structure-function relationships during segregated and integrated network states of human brain functional connectivity.

Science.gov (United States)

Fukushima, Makoto; Betzel, Richard F; He, Ye; van den Heuvel, Martijn P; Zuo, Xi-Nian; Sporns, Olaf

2018-04-01

Structural white matter connections are thought to facilitate integration of neural information across functionally segregated systems. Recent studies have demonstrated that changes in the balance between segregation and integration in brain networks can be tracked by time-resolved functional connectivity derived from resting-state functional magnetic resonance imaging (rs-fMRI) data and that fluctuations between segregated and integrated network states are related to human behavior. However, how these network states relate to structural connectivity is largely unknown. To obtain a better understanding of structural substrates for these network states, we investigated how the relationship between structural connectivity, derived from diffusion tractography, and functional connectivity, as measured by rs-fMRI, changes with fluctuations between segregated and integrated states in the human brain. We found that the similarity of edge weights between structural and functional connectivity was greater in the integrated state, especially at edges connecting the default mode and the dorsal attention networks. We also demonstrated that the similarity of network partitions, evaluated between structural and functional connectivity, increased and the density of direct structural connections within modules in functional networks was elevated during the integrated state. These results suggest that, when functional connectivity exhibited an integrated network topology, structural connectivity and functional connectivity were more closely linked to each other and direct structural connections mediated a larger proportion of neural communication within functional modules. Our findings point out the possibility of significant contributions of structural connections to integrative neural processes underlying human behavior.

Using Structural Equation Modeling to Examine the Effects of Sex and Physical Activity on the Metabolic Syndrome and Health-related Quality of Life Relationship

Directory of Open Access Journals (Sweden)

Peter D. Hart

2018-01-01

Full Text Available Objectives The purpose of this study was to use structural equation modeling (SEM to investigate the moderating effects of sex and the mediating effects of physical activity (PA on the metabolic syndrome (MetS and health-related quality of life (HRQOL relationship. Methods The 2013-14 NHANES was used and included 1,077 adults 50+ years of age. A latent construct of MetS was created using five observed variables: waist circumference, HDL cholesterol, triglycerides, fasting glucose, and mean arterial pressure. A PA variable was created from self-reported moderate and vigorous recreational activity and converted to quartiles of moderate-to-vigorous PA minutes per week. HRQOL was assessed from a question regarding self-rated general health and dichotomized to indicate poor/good HRQOL. Results The MetS latent model showed adequate fit (χ2/df=2.47, GFI=0.99, CFI=0.99, and RMSEA=0.04 and significantly (P<.001 predicted all observed variables. The structural model also showed adequate fit with significant direct effects of MetS on HRQOL (β= −0.118, P<0.001 and PA on HRQOL (β=0.176, P<0.001. The effect of MetS on HRQOL (β= −0.048, P=0.001 through PA revealed that PA mediates the relationship. The multi-group analysis showed that the structural model was significantly different between males and females, with PA completely mediating the MetS and HRQOL relationship in males and partially mediating the relationship in females. Conclusions Results from this study support the use of SEM for investigating moderating and mediating effects while simultaneously measuring a latent construct. Additionally, PA was a stronger mediator to the MetS and HRQOL relationship in older males than in older females.

Spiders in Motion: Demonstrating Adaptation, Structure-Function Relationships, and Trade-Offs in Invertebrates

Science.gov (United States)

Bowlin, Melissa S.; McLeer, Dorothy F.; Danielson-Francois, Anne M.

2014-01-01

Evolutionary history and structural considerations constrain all aspects of animal physiology. Constraints on invertebrate locomotion are especially straightforward for students to observe and understand. In this exercise, students use spiders to investigate the concepts of adaptation, structure-function relationships, and trade-offs. Students…

Prognostic significance of delayed structural recovery after macular hole surgery

DEFF Research Database (Denmark)

Christensen, Ulrik C; Krøyer, Kristian; Sander, Birgit

2009-01-01

was used; however, secondary macular hole surgery had a significant influence on diameter of photoreceptor layer discontinuity at 3 months. CONCLUSIONS: Structural recovery in the form of photoreceptor layer discontinuity with a diameter of more than approximately 1500 microm 3 months after macular hole...

Relationship between the structural stability with the types and land uses in southeastern Spain

International Nuclear Information System (INIS)

Marin Sanleandro, P.; Sanchez Navarro, A.; Delgado Iniesta, M. J.; Fernandez-Delgado Juarez, M.

2009-01-01

Structural stability is one of the most important physical properties and is proposed as an indicator of quality. The aim of this study is to see the possible relationship between this property with soil types and uses of them. In this paper we have selected the Mazarron area based on their environmental characteristics and has taken forty-one topsoil samples, after analysis and study of the relationship between its structural stability with soil types and uses of same, we find a closer relationship in the case of uses that type, so that the natural soil as the percentage of stable aggregates close to 75%, while in soils anthropized this value reaches 44 %. (Author) 6 refs

The Relationship between Ownership Structure and Risk Management: Evidence from Iran

OpenAIRE

Sheyda Lotfi; Ataollah Mohammadi

2014-01-01

This research aims to study the relationship between the Ownership Structure and Risk Management in time period between 2007 to 2013 based on a sample including 642 Year_Firm among campanies listed in Tehran Stock Exchange. In following for each of the variables related to the Ownership Structure such as Institutional Ownership, Management ownership, Family Ownership, and Ownership Concentration, a hypothesis is formulated and its impact upon the Risk Management is investigated. The simple li...

Structural relationships in high temperature superconductors

International Nuclear Information System (INIS)

Schuller, I.K.; Segre, C.U.; Hinks, D.G.; Jorgensen, J.D.; Soderholm, L.; Beno, M.; Zhang, K.

1987-09-01

The recent discovery of two types of metallic copper oxide compounds which are superconducting to above 90 0 K has renewed interest in the search for new high temperature superconducting materials. It is significant that both classes of compounds, La/sub 2-x/Sr/sub x/CuO/sub 4-y/ and YBa 2 Cu 3 O/sub 7-δ/ are intimately related to the extensively studied perovskite family. Both compounds contain highly oxidized, covalently bonded Cu-O sublattices, however, they differ in geometry. In this paper we discuss the relationship of these features to the superconducting properties. 30 refs., 6 figs

Calculation of Quantitative Structure-Activity Relationship Descriptors of Artemisinin Derivatives

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Jambalsuren Bayarmaa

2008-06-01

Full Text Available Quantitative structure-activity relationships are based on the construction of predictive models using a set of known molecules and associated activity value. This accurate methodology, developed with adequate mathematical and computational tools, leads to a faster, cheaper and more comprehensive design of new products, reducing the experimental synthesis and testing on animals. Preparation of the QSAR models of artemisinin derivatives was carried out by the genetic function algorithm (GFA method for 91 molecules. The results show some relationships to the observed antimalarial activities of the artemisinin derivatives. The most statistically signi fi cant regression equation obtained from the fi nal GFA relates to two molecular descriptors.

Statistically significant dependence of the Xaa-Pro peptide bond conformation on secondary structure and amino acid sequence

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Leitner Dietmar

2005-04-01

Full Text Available Abstract Background A reliable prediction of the Xaa-Pro peptide bond conformation would be a useful tool for many protein structure calculation methods. We have analyzed the Protein Data Bank and show that the combined use of sequential and structural information has a predictive value for the assessment of the cis versus trans peptide bond conformation of Xaa-Pro within proteins. For the analysis of the data sets different statistical methods such as the calculation of the Chou-Fasman parameters and occurrence matrices were used. Furthermore we analyzed the relationship between the relative solvent accessibility and the relative occurrence of prolines in the cis and in the trans conformation. Results One of the main results of the statistical investigations is the ranking of the secondary structure and sequence information with respect to the prediction of the Xaa-Pro peptide bond conformation. We observed a significant impact of secondary structure information on the occurrence of the Xaa-Pro peptide bond conformation, while the sequence information of amino acids neighboring proline is of little predictive value for the conformation of this bond. Conclusion In this work, we present an extensive analysis of the occurrence of the cis and trans proline conformation in proteins. Based on the data set, we derived patterns and rules for a possible prediction of the proline conformation. Upon adoption of the Chou-Fasman parameters, we are able to derive statistically relevant correlations between the secondary structure of amino acid fragments and the Xaa-Pro peptide bond conformation.

Analysis Relationship Among Descriptor, References and Citation to Contruct the Inherent Structure of Document Collection

International Nuclear Information System (INIS)

Hasibuan, Zainal A.; Mustangimah

2001-01-01

There are many characteristics can be used to identify a document which cover characteristics of the documents, cited documents, and citing documents This research explored the inherent structure of a document collection as one of main components of information retrieval system. The characteristics examined are: descriptors, references (cited documents), and citations (citing documents). Three independent variables were studied: co-descriptor, bibliographic coupling, and co-citation. A test collection was constructed by searching on a single descriptor i nformation retrieval i n the CD-ROM version of Education Resource Information Clearinghouse (ERIC), covering the period 1981 through 1985. Descriptors were extracted from ERIC; cited and citing documents associated with the test collection were derived from Social Sciences Citation Index (SSCI), covering the period 1981 through 1990. Three hypothesis were tested in this study, that are: (1) the higher the frequency of co-descriptors between documents, the higher the frequencies of their bibliographic coupling and co-citation; (2) the higher the frequency of bibliographic coupling between documents, the higher the frequencies of their co-citation and co-descriptors; and (3) the higher the frequency of co-citation between documents, the higher the frequencies of their co-descriptors and bibliographic coupling. The results showed that all of three hypothesis are supported statistically and there is a significant linear relationship among the observed variables. It is mean that there is a significant relationship among descriptors, references, and citation, so that it can be used to construct the inherent structure of document collection in order to improve information retrieval system performance

[Relationships between microscope structure and thermodynamic properties

International Nuclear Information System (INIS)

Wu, R.S.; Lee, L.L.; Cochran, D.

1990-01-01

This paper exhibits on the molecular level, the relationships between the microscopic structure and thermodynamic properties of dilute supercritical solutions by application of the integral equation theories for molecular distribution functions. To solve the integral equations, the authors use Baxter's Wiener-Hopf factorization of the Ornstein-Zernike equations and then apply this method to binary Lennard-Jones mixtures. A number of closure relations have been used: such as the Percus-Yevick (PY), the reference hypernetted chain (RHNC), the hybrid mean spherical approximation (HMSA), and the reference interaction-site (RISM) methods. The authors examine the microstructures of several important classes of supercritical mixtures, including the usual attractive-type and the less known repulsive-type solutions. The clustering of solvent molecules for solvent-solute structures in the attractive mixtures and, correspondingly, the solvent cavitation in the repulsive mixtures are clearly demonstrated. These are shown to be responsible for the large negative growth of the solute partial molar volumes in the attractive case and the positive growth in the repulsive case

A structural equation model of patient-healthcare provider relationships and HIV-infected patient outcomes in Chinese populations.

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Chen, Wei-Ti; Shiu, Chengshi; Yang, Joyce P; Chuang, Peing; Zhang, Lin; Bao, Meijuan; Lu, Hongzhou

2018-03-01

Obtaining maximum antiretroviral therapy (ART) adherence is critical for maintaining a high CD4 count and strong immune function in PLWHA. Key factors for achieving optimum adherence include good medication self-efficacy, decreased medication-taking difficulties, and positive patient-healthcare provider (HCP) relationships. Limited studies have analyzed the correlation of these factors and ART adherence in Chinese population. In this paper, structural equation modeling was performed to assess the proposed model of relations between patient-HCP relationships and adherence. Audio Computer-Assisted Self-Interview (ACASI) software was used to collect data on ART adherence and patient variables among 227 PLWHA in Shanghai and Taipei. Participants completed a one-time 60-minute ACASI survey that consisted of standardized measures to assess demographics, recent CD4 counts, self-efficacy, patient-HCP relationship, adherence, and medication-taking difficulties. The data shown the relationship between patient-HCP relationships and adherence was significantly consistent with mediation by medication self-efficacy. However, patient-HCP interaction did not directly influence medication-taking difficulties, and medication-taking difficulties did not significantly affect CD4 counts. Furthermore, patient-HCP interactions did not directly impact CD4 counts; rather, the relation was consistent with mediation (by either better medication self-efficacy or better adherence) or by improved adherence alone. Future interventions should be designed to enhance self-management and provide better patient-HCP communication. This improved communication will enhance medication self-efficacy and decrease medication-taking difficulties. This in turn will improve medication adherence and immune function among PLWHA.

THE SIGNIFICANCE OF STRUCTURAL AND GEOLOGICAL RELATIONSHIP ASSESSMENT IN THE CONSTRUCTION OF THE OMBLA UNDERGROUND HYDROELECTRIC POWER PLANT

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Renato Buljan

1997-12-01

Full Text Available The construction design of the underground hydroelectric plant Ombla required geological and structural investigations to he carried out. Due to past earthquakes in the area permanent tectonic movements were inferred. Therefore, in the wider and adjacent surroundings of the Ombla spring it was necessary to analyze the structural fabric and the geodynamic characteristics of the area. The most active zone encountered is the front part of a thrust fault belonging to the Dinaricum regional structural unit. The compressive regime is maintained as a response to the regional stress of an approximately S-N orientation. Different displacements of various parts of the Dinaricum unit are present. Along the rim of the structural blocks, the Hum-Om-bla fault zone extends, accompanied by left transcurrent faults, Through this zone the main groundwater drainage occurs supplying the Ombla spring. In the local Ombla spring area this zone is characterized by three sub-blocks and three major faults. The most important fault for the vital facilities of the Ombla hydroelectric power plant is the Pločice fault which divides the structural sub-blocks. Along this fault zone there are four mutually connected. The lowest two arc active groundwater draining systems supplying the Ombla spring. The data on local stress implies the following deformation of sub-blocks: sub-blocks 2c and 2f are displaced along normal faults from 20° to 30° to the left, downwards, while the sub-block 2 d is displaced along the Pločice thrust fault of 100° to 130° to the left, upwards. The structural data confirmed that the building of an underground dam with a height from 100 to 130 m was feasible. The connection between the caverns and the fault zone was determined. The unfavorable position of the active Pločice fault zone imposes the construction of vital Ombla power plant facilities underground.

Applying Exploratory Structural Equation Modeling to Examine the Student-Teacher Relationship Scale in a Representative Greek Sample.

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Tsigilis, Nikolaos; Gregoriadis, Athanasios; Grammatikopoulos, Vasilis; Zachopoulou, Evridiki

2018-01-01

Teacher-child relationships in early childhood are a fundamental prerequisite for children's social, emotional, and academic development. The Student-Teacher Relationship Scale (STRS) is one of the most widely accepted and used instruments that evaluate the quality of teacher-child relationships. STRS is a 28-item questionnaire that assess three relational dimensions, Closeness, Conflict, and Dependency. The relevant literature has shown a pattern regarding the difficulty to support the STRS factor structure with CFA, while it is well-documented with EFA. Recently, a new statistical technique was proposed to combine the best of the CFA and EFA namely, the Exploratory Structural Equation Modeling (ESEM). The purpose of this study was (a) to examine the factor structure of the STRS in a Greek national sample. Toward this end, the ESEM framework was applied in order to overcome the limitations of EFA and CFA, (b) to confirm previous findings about the cultural influence in teacher-child relationship patterns, and (c) to examine the invariance of STRS across gender and age. Early educators from a representative Greek sample size of 535 child care and kindergarten centers completed the STRS for 4,158 children. CFA as well as ESEM procedures were implemented. Results showed that ESEM provided better fit to the data than CFA in both groups, supporting the argument that CFA is an overly restrictive approach in comparison to ESEM for the study of STRS. All primary loadings were statistically significant and were associated with their respective latent factors. Contrary to the existing literature conducted in USA and northern Europe, the association between Closeness and Dependency yielded a positive correlation. This finding is in line with previous studies conducted in Greece and confirm the existence of cultural differences in teacher-child relationships. In addition, findings supported the configural, metric, scalar, and variance/covariance equivalence of the STRS

Applying Exploratory Structural Equation Modeling to Examine the Student-Teacher Relationship Scale in a Representative Greek Sample

Directory of Open Access Journals (Sweden)

Nikolaos Tsigilis

2018-05-01

Full Text Available Teacher-child relationships in early childhood are a fundamental prerequisite for children's social, emotional, and academic development. The Student-Teacher Relationship Scale (STRS is one of the most widely accepted and used instruments that evaluate the quality of teacher-child relationships. STRS is a 28-item questionnaire that assess three relational dimensions, Closeness, Conflict, and Dependency. The relevant literature has shown a pattern regarding the difficulty to support the STRS factor structure with CFA, while it is well-documented with EFA. Recently, a new statistical technique was proposed to combine the best of the CFA and EFA namely, the Exploratory Structural Equation Modeling (ESEM. The purpose of this study was (a to examine the factor structure of the STRS in a Greek national sample. Toward this end, the ESEM framework was applied in order to overcome the limitations of EFA and CFA, (b to confirm previous findings about the cultural influence in teacher-child relationship patterns, and (c to examine the invariance of STRS across gender and age. Early educators from a representative Greek sample size of 535 child care and kindergarten centers completed the STRS for 4,158 children. CFA as well as ESEM procedures were implemented. Results showed that ESEM provided better fit to the data than CFA in both groups, supporting the argument that CFA is an overly restrictive approach in comparison to ESEM for the study of STRS. All primary loadings were statistically significant and were associated with their respective latent factors. Contrary to the existing literature conducted in USA and northern Europe, the association between Closeness and Dependency yielded a positive correlation. This finding is in line with previous studies conducted in Greece and confirm the existence of cultural differences in teacher-child relationships. In addition, findings supported the configural, metric, scalar, and variance/covariance equivalence of

Genetic Structure and Relationship Analysis of an Association Population in Jute (Corchorus spp. Evaluated by SSR Markers.

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Liwu Zhang

Full Text Available Population structure and relationship analysis is of great importance in the germplasm utilization and association mapping. Jute, comprised of white jute (C. capsularis L and dark jute (C. olitorius L, is second to cotton in its commercial significance in the world. Here, we assessed the genetic structure and relationship in a panel of 159 jute accessions from 11 countries and regions using 63 SSRs. The structure analysis divided the 159 jute accessions from white and dark jute into Co and Cc group, further into Co1, Co2, Cc1 and Cc2 subgroups. Out of Cc1 subgroup, 81 accessions were from China and the remaining 10 accessions were from India (2, Japan (5, Thailand, Vietnam (2 and Pakistan (1. Out of Cc2 subgroup, 35 accessions were from China, and the remaining 3 accessions were from India, Pakistan and Thailand respectively. It can be inferred that the genetic background of these jute accessions was not always correlative with their geographical regions. Similar results were found in Co1 and Co2 subgroups. Analysis of molecular variance revealed 81% molecular variation between groups but it was low (19% within subgroups, which further confirmed the genetic differentiation between the two groups. The genetic relationship analysis showed that the most diverse genotypes were Maliyeshengchangguo and Changguozhongyueyin in dark jute, BZ-2-2, Aidianyehuangma, Yangjuchiyuanguo, Zijinhuangma and Jute 179 in white jute, which could be used as the potential parents in breeding programs for jute improvement. These results would be very useful for association studies and breeding in jute.

Structure-solubility relationships in fluoride-containing phosphate based bioactive glasses

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Shaharyar, Yaqoot

The dissolution of fluoride-containing bioactive glasses critically affects their biomedical applications. Most commercial fluoride-releasing bioactive glasses have been designed in the soda-lime-silica system. However, their relatively slow chemical dissolution and the adverse effect of fluoride on their bioactivity are stimulating the study of novel biodegradable materials with higher bioactivity, such as biodegradable phosphate-based bioactive glasses, which can be a viable alternative for applications where a fast release of active ions is sought. In order to design new biomaterials with controlled degradability and high bioactivity, it is essential to understand the connection between chemical composition, molecular structure, and solubility in physiological fluids.Accordingly, in this work we have combined the strengths of various experimental techniques with Molecular Dynamics (MD) simulations, to elucidate the impact of fluoride ions on the structure and chemical dissolution of bioactive phosphate glasses in the system: 10Na2O - (45-x) CaO - 45P2O5 - xCaF2, where x varies between 0 -- 10 mol.%. NMR and MD data reveal that the medium-range atomic-scale structure of thse glasses is dominated by Q2 phosphate units followed by Q1 units, and the MD simulations further show that fluoride tends to associate with network modifier cations to form alkali/alkaline-earth rich ionic aggregates. On a macroscopic scale, we find that incorporating fluoride in phosphate glasses does not affect the rate of apatite formation on the glass surface in simulated body fluid (SBF). However, fluoride has a marked favorable impact on the glass dissolution in deionized water. Similarly, fluoride incorporation in the glasses results in significant weight gain due to adsorption of water (in the form of OH ions). These macroscopic trends are discussed on the basis of the F effect on the atomistic structure of the glasses, such as the F-induced phosphate network re-polymerization, in a

Relationship of carotid arterial functional and structural changes to left atrial volume in untreated hypertension.

Science.gov (United States)

Jaroch, Joanna; Rzyczkowska, Barbara; Bociąga, Zbigniew; Vriz, Olga; Driussi, Caterina; Loboz-Rudnicka, Maria; Dudek, Krzysztof; Łoboz-Grudzień, Krystyna

2016-04-01

The contribution of arterial functional and structural changes to left ventricular (LV) diastolic dysfunction has been the area of recent research. There are some studies on the relationship between arterial stiffness (a.s.) and left atrial (LA) remodelling as a marker of diastolic burden. Little is known about the association of arterial structural changes and LA remodelling in hypertension (H). The aim of this study was to examine the relationship between carotid a.s. and intima-media thickness (IMT) and LA volume in subjects with H. The study included 245 previously untreated hypertensives (166 women and 79 men, mean age 53.7 ± 11.8 years). Each patient was subjected to echocardiography with measurement of LA volume, evaluation of left ventricular hypertrophy (LVH) and LV systolic/diastolic function indices, integrated assessment of carotid IMT and echo-tracking of a.s. and wave reflection parameters. Univariate regression analysis revealed significant correlations between indexed LA volume and selected clinical characteristics, echocardiographic indices of LVH and LV diastolic/systolic function and a.s./wave reflection parameters. The following parameters were identified as independent determinants of indexed LA volume on multivariate regression analysis: diastolic blood pressure (beta = -0.229, P arterial stiffness but not intima-media thickness and LA volume in patients with untreated hypertension.

Structure modification and functionality of whey proteins: quantitative structure-activity relationship approach.

Science.gov (United States)

Nakai, S; Li-Chan, E

1985-10-01

According to the original idea of quantitative structure-activity relationship, electric, hydrophobic, and structural parameters should be taken into consideration for elucidating functionality. Changes in these parameters are reflected in the property of protein solubility upon modification of whey proteins by heating. Although solubility is itself a functional property, it has been utilized to explain other functionalities of proteins. However, better correlations were obtained when hydrophobic parameters of the proteins were used in conjunction with solubility. Various treatments reported in the literature were applied to whey protein concentrate in an attempt to obtain whipping and gelling properties similar to those of egg white. Mapping simplex optimization was used to search for the best results. Improvement in whipping properties by pepsin hydrolysis may have been due to higher protein solubility, and good gelling properties resulting from polyphosphate treatment may have been due to an increase in exposable hydrophobicity. However, the results of angel food cake making were still unsatisfactory.

Relationships between structural social capital, knowledge identification capability and external knowledge acquisition

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Beatriz Ortiz

2017-07-01

Full Text Available Purpose - The purpose of this paper is to analyze the mediating effect of the identification of valuable external knowledge on the relationship between the development of inter-organizational ties (structural social capital and the acquisition of external knowledge. Design/methodology/approach - Using a sample of 87 firms from Spanish biotechnology and pharmaceutics industries, the authors have tested the proposed mediation hypothesis by applying the partial least squares technique to a structural equations model. Findings - The study results show that those firms with stronger, more frequent and closer inter-relationships are able to increase the amount of intentionally acquired knowledge, partly due to the greater level of development of their knowledge identification capability. Thus, firms with a higher capability to recognize the value of the knowledge embedded in their inter-organizational networks will be more likely to design better strategies to acquire and integrate such knowledge into their current knowledge bases for either present or future use. Originality/value - This research contributes to knowledge management and social capital literature by means of the study of two key determinants of knowledge acquisition – structural social capital and knowledge identification capability – and the explanation of their relationships of mutual influence. The paper thus tries to fill this literature gap and connects the relational perspective of social capital with the knowledge-based view from a strategic point of view.

The Structure of Phonological Processing and Its Relationship to Basic Reading

Science.gov (United States)

Nelson, Jason M.; Lindstrom, Jennifer H.; Lindstrom, Will; Denis, Daniel

2012-01-01

We investigated various structural models of phonological processing and the relationship of phonological processing abilities to basic reading. Data were collected on 116 kindergarten and first grade students. The specific ability model, which included phonological awareness, phonological memory, and rapid automatized naming as separate…

Neurological soft signs and their relationships to neurocognitive functions: a re-visit with the structural equation modeling design.

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Raymond C K Chan

Full Text Available BACKGROUND: Neurological soft signs and neurocognitive impairments have long been considered important features of schizophrenia. Previous correlational studies have suggested that there is a significant relationship between neurological soft signs and neurocognitive functions. The purpose of the current study was to examine the underlying relationships between these two distinct constructs with structural equation modeling (SEM. METHODS: 118 patients with schizophrenia and 160 healthy controls were recruited for the current study. The abridged version of the Cambridge Neurological Inventory (CNI and a set of neurocognitive function tests were administered to all participants. SEM was then conducted independently in these two samples to examine the relationships between neurological soft signs and neurocognitive functions. RESULTS: Both the measurement and structural models showed that the models fit well to the data in both patients and healthy controls. The structural equations also showed that there were modest to moderate associations among neurological soft signs, executive attention, verbal memory, and visual memory, while the healthy controls showed more limited associations. CONCLUSIONS: The current findings indicate that motor coordination, sensory integration, and disinhibition contribute to the latent construct of neurological soft signs, whereas the subset of neurocognitive function tests contribute to the latent constructs of executive attention, verbal memory, and visual memory in the present sample. Greater evidence of neurological soft signs is associated with more severe impairment of executive attention and memory functions. Clinical and theoretical implications of the model findings are discussed.

Relationship between chemical structure of soil organic matter and intra-aggregate pore structure: evidence from X-ray computed micro-tomography

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Kravchenko, Alexandra; Grandy, Stuart A.

2014-05-01

Understanding chemical structure of soil organic matter (SOM) and factors that affect it are vital for gaining understanding of mechanisms of C sequestration by soil. Physical protection of C by adsorption to mineral particles and physical disconnection between C sources and microbial decomposers is now regarded as the key component of soil C sequestration. Both of the processes are greatly influenced by micro-scale structure and distribution of soil pores. However, because SOM chemical structure is typically studied in disturbed (ground and sieved) soil samples the experimental evidence of the relationships between soil pore structure and chemical structure of SOM are still scarce. Our study takes advantage of the X-ray computed micro-tomography (µ-CT) tools that enable non-destructive analysis of pore structure in intact soil samples. The objective of this study is to examine the relationship between SOM chemical structure and pore-characteristics in intact soil macro-aggregates from two contrasting long-term land uses. The two studied land use treatments are a conventionally tilled corn-soybean-wheat rotation treatment and a native succession vegetation treatment removed from agricultural use >20 years ago. The study is located in southwest Michigan, USA, on sandy-loam Typic Hapludalfs. For this study we used soil macro-aggregates 4-6 mm in size collected at 0-15 cm depth. The aggregate size was selected so as both to enable high resolution of µ-CT and to provide sufficient amount of soil for C measurements. X-ray µ-CT scanning was conducted at APS Argonne at a scanning resolution of 14 µm. Two scanned aggregates (1 per treatment) were used in this preliminary study. Each aggregate was cut into 7 "geo-referenced" sections. Analyses of pore characteristics in each section were conducted using 3DMA and ImageJ image analysis tools. SOM chemistry was analyzed using pyrolysis/gas chromatography-mass spectroscopy. Results demonstrated that the relationships

Dysphagia and trismus after concomitant chemo-Intensity-Modulated Radiation Therapy (chemo-IMRT) in advanced head and neck cancer; dose-effect relationships for swallowing and mastication structures.

Science.gov (United States)

van der Molen, Lisette; Heemsbergen, Wilma D; de Jong, Rianne; van Rossum, Maya A; Smeele, Ludi E; Rasch, Coen R N; Hilgers, Frans J M

2013-03-01

Prospective assessment of dysphagia and trismus in chemo-IMRT head and neck cancer patients in relation to dose-parameters of structures involved in swallowing and mastication. Assessment of 55 patients before, 10-weeks (N=49) and 1-year post-treatment (N=37). Calculation of dose-volume parameters for swallowing (inferior (IC), middle (MC), and superior constrictors (SC)), and mastication structures (e.g. masseter). Investigation of relationships between dose-parameters and endpoints for swallowing problems (videofluoroscopy-based laryngeal Penetration-Aspiration Scale (PAS), and study-specific structured questionnaire) and limited mouth-opening (measurements and questionnaire), taking into account baseline scores. At 10-weeks, volume of IC receiving ≥60 Gy (V60) and mean dose IC were significant predictors for PAS. One-year post-treatment, reported problems with swallowing solids were significantly related to masseter dose-parameters (mean, V20, V40 and V60) and an inverse relationship (lower dose related to a higher probability) was observed for V60 of the IC. Dose-parameters of masseter and pterygoid muscles were significant predictors of trismus at 10-weeks (mean, V20, and V40). At 1-year, dose-parameters of all mastication structures were strong predictors for subjective mouth-opening problems (mean, max, V20, V40, and V60). Dose-effect relationships exist for dysphagia and trismus. Therefore treatment plans should be optimized to avoid these side effects. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Dysphagia and trismus after concomitant chemo-Intensity-Modulated Radiation Therapy (chemo-IMRT) in advanced head and neck cancer; dose–effect relationships for swallowing and mastication structures

International Nuclear Information System (INIS)

Molen, Lisette van der; Heemsbergen, Wilma D.; Jong, Rianne de; Rossum, Maya A. van; Smeele, Ludi E.; Rasch, Coen R.N.; Hilgers, Frans J.M.

2013-01-01

Background and purpose: Prospective assessment of dysphagia and trismus in chemo-IMRT head and neck cancer patients in relation to dose-parameters of structures involved in swallowing and mastication. Material and methods: Assessment of 55 patients before, 10-weeks (N = 49) and 1-year post-treatment (N = 37). Calculation of dose–volume parameters for swallowing (inferior (IC), middle (MC), and superior constrictors (SC)), and mastication structures (e.g. masseter). Investigation of relationships between dose-parameters and endpoints for swallowing problems (videofluoroscopy-based laryngeal Penetration-Aspiration Scale (PAS), and study-specific structured questionnaire) and limited mouth-opening (measurements and questionnaire), taking into account baseline scores. Results: At 10-weeks, volume of IC receiving ⩾60 Gy (V60) and mean dose IC were significant predictors for PAS. One-year post-treatment, reported problems with swallowing solids were significantly related to masseter dose-parameters (mean, V20, V40 and V60) and an inverse relationship (lower dose related to a higher probability) was observed for V60 of the IC. Dose-parameters of masseter and pterygoid muscles were significant predictors of trismus at 10-weeks (mean, V20, and V40). At 1-year, dose-parameters of all mastication structures were strong predictors for subjective mouth-opening problems (mean, max, V20, V40, and V60). Conclusions: Dose–effect relationships exist for dysphagia and trismus. Therefore treatment plans should be optimized to avoid these side effects

Analysis of structural relationship among the occupational dysfunction on the psychological problem in healthcare workers: a study using structural equation modeling

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Mutsumi Teraoka

2015-11-01

Full Text Available Purpose. The purpose of this study is to demonstrate the hypothetical model based on structural relationship with the occupational dysfunction on psychological problems (stress response, burnout syndrome, and depression in healthcare workers.Method. Three cross sectional studies were conducted to assess the following relations: (1 occupational dysfunction on stress response (n = 468, (2 occupational dysfunction on burnout syndrome (n = 1,142, and (3 occupational dysfunction on depression (n = 687. Personal characteristics were collected through a questionnaire (such as age, gender, and job category, opportunities for refreshment, time spent on leisure activities, and work relationships as well as the Classification and Assessment of Occupational Dysfunction (CAOD. Furthermore, study 1 included the Stress Response Scale-18 (SRS-18, study 2 used the Japanese Burnout Scale (JBS, and study 3 employed the Center for Epidemiological Studies Depression Scale (CES-D. The Kolmogorov–Smirnov test, confirmatory factor analysis (CFA, exploratory factor analysis (EFA, and path analysis of structural equation modeling (SEM analysis were used in all of the studies. EFA and CFA were used to measure structural validity of four assessments; CAOD, SRS-18, JBS, and CES-D. For examination of a potential covariate, we assessed the correlation of the total and factor score of CAOD and personal factors in all studies. Moreover, direct and indirect effects of occupational dysfunction on stress response (Study 1, burnout syndrome (Study 2, and depression (Study 3 were also analyzed.Results. In study 1, CAOD had 16 items and 4 factors. In Study 2 and 3, CAOD had 16 items and 5 factors. SRS-18 had 18 items and 3 factors, JBS had 17 items and 3 factors, and CES-D had 20 items and 4 factors. All studies found that there were significant correlations between the CAOD total score and the personal factor that included opportunities for refreshment, time spent on leisure

Analysis of structural relationship among the occupational dysfunction on the psychological problem in healthcare workers: a study using structural equation modeling.

Science.gov (United States)

Teraoka, Mutsumi; Kyougoku, Makoto

2015-01-01

Purpose. The purpose of this study is to demonstrate the hypothetical model based on structural relationship with the occupational dysfunction on psychological problems (stress response, burnout syndrome, and depression) in healthcare workers. Method. Three cross sectional studies were conducted to assess the following relations: (1) occupational dysfunction on stress response (n = 468), (2) occupational dysfunction on burnout syndrome (n = 1,142), and (3) occupational dysfunction on depression (n = 687). Personal characteristics were collected through a questionnaire (such as age, gender, and job category, opportunities for refreshment, time spent on leisure activities, and work relationships) as well as the Classification and Assessment of Occupational Dysfunction (CAOD). Furthermore, study 1 included the Stress Response Scale-18 (SRS-18), study 2 used the Japanese Burnout Scale (JBS), and study 3 employed the Center for Epidemiological Studies Depression Scale (CES-D). The Kolmogorov-Smirnov test, confirmatory factor analysis (CFA), exploratory factor analysis (EFA), and path analysis of structural equation modeling (SEM) analysis were used in all of the studies. EFA and CFA were used to measure structural validity of four assessments; CAOD, SRS-18, JBS, and CES-D. For examination of a potential covariate, we assessed the correlation of the total and factor score of CAOD and personal factors in all studies. Moreover, direct and indirect effects of occupational dysfunction on stress response (Study 1), burnout syndrome (Study 2), and depression (Study 3) were also analyzed. Results. In study 1, CAOD had 16 items and 4 factors. In Study 2 and 3, CAOD had 16 items and 5 factors. SRS-18 had 18 items and 3 factors, JBS had 17 items and 3 factors, and CES-D had 20 items and 4 factors. All studies found that there were significant correlations between the CAOD total score and the personal factor that included opportunities for refreshment, time spent on leisure

The Relationship between Self-Leadership and Personality: A Comparison of Hierarchical Factor Structures

OpenAIRE

Houghton, Jeffery D.

2000-01-01

This study examined the relationship between self-leadership and personality through an analysis and comparison of hierarchical factor structures. More specifically, this study examined the relationships between the self-leadership dimensions of behavior-focused strategies, natural reward strategies, and constructive thought strategies, and the personality dimensions of extraversion, emotional stability, and conscientiousness. The results of the study provide evidence that the self-leadershi...

Relationships Between Lower-Body Muscle Structure and Lower-Body Strength, Power, and Muscle-Tendon Complex Stiffness.

Science.gov (United States)

Secomb, Josh L; Lundgren, Lina E; Farley, Oliver R L; Tran, Tai T; Nimphius, Sophia; Sheppard, Jeremy M

2015-08-01

The purpose of this study was to determine whether any relationships were present between lower-body muscle structure and strength and power qualities. Fifteen elite male surfing athletes performed a battery of lower-body strength and power tests, including countermovement jump (CMJ), squat jump (SJ), isometric midthigh pull (IMTP), and had their lower-body muscle structure assessed with ultrasonography. In addition, lower-body muscle-tendon complex (MTC) stiffness and dynamic strength deficit (DSD) ratio were calculated from the CMJ and IMTP. Significant relationships of large to very large strength were observed between the vastus lateralis (VL) thickness of the left (LVL) and right (RVL) leg and peak force (PF) (r = 0.54-0.77, p well as IMTP PF (r = 0.53-0.60, p = 0.02-0.04). Furthermore, large relationships were found between left lateral gastrocnemius (LG) pennation angle and SJ and IMTP PF (r = 0.53, p = 0.04, and r = 0.70, p < 0.01, respectively) and between LG and IMTP relative PF (r = 0.63, p = 0.01). Additionally, large relationships were identified between lower-body MTC stiffness and DSD ratio (r = 0.68, p < 0.01), right (LG) pennation angle (r = 0.51, p = 0.05), CMJ PF (r = 0.60, p = 0.02), and jump height (r = 0.53, p = 0.04). These results indicate that greater VL thickness and increased LG pennation angle are related to improved performance in the CMJ, SJ, and IMTP. Furthermore, these results suggest that lower-body MTC stiffness explains a large amount of variance in determining an athlete's ability to rapidly apply force during a dynamic movement.

The dynamic relationship between structural change and CO2 emissions in Malaysia: a cointegrating approach.

Science.gov (United States)

Ali, Wajahat; Abdullah, Azrai; Azam, Muhammad

2017-05-01

The current study investigates the dynamic relationship between structural changes, real GDP per capita, energy consumption, trade openness, population density, and carbon dioxide (CO 2 ) emissions within the EKC framework over a period 1971-2013. The study used the autoregressive distributed lagged (ARDL) approach to investigate the long-run relationship between the selected variables. The study also employed the dynamic ordinary least squared (DOLS) technique to obtain the robust long-run estimates. Moreover, the causal relationship between the variables is explored using the VECM Granger causality test. Empirical results reveal a negative relationship between structural change and CO 2 emissions in the long run. The results indicate a positive relationship between energy consumption, trade openness, and CO 2 emissions. The study applied the turning point formula of Itkonen (2012) rather than the conventional formula of the turning point. The empirical estimates of the study do not support the presence of the EKC relationship between income and CO 2 emissions. The Granger causality test indicates the presence of long-run bidirectional causality between energy consumption, structural change, and CO 2 emissions in the long run. Economic growth, openness to trade, and population density unidirectionally cause CO 2 emissions. These results suggest that the government should focus more on information-based services rather than energy-intensive manufacturing activities. The feedback relationship between energy consumption and CO 2 emissions suggests that there is an ominous need to refurbish the energy-related policy reforms to ensure the installations of some energy-efficient modern technologies.

Relationships between avian richness and landscape structure at multiple scales using multiple landscapes

Science.gov (United States)

Michael S. Mitchell; Scott H. Rutzmoser; T. Bently Wigley; Craig Loehle; John A. Gerwin; Patrick D. Keyser; Richard A. Lancia; Roger W. Perry; Christopher L. Reynolds; Ronald E. Thill; Robert Weih; Don White; Petra Bohall Wood

2006-01-01

Little is known about factors that structure biodiversity on landscape scales, yet current land management protocols, such as forest certification programs, place an increasing emphasis on managing for sustainable biodiversity at landscape scales. We used a replicated landscape study to evaluate relationships between forest structure and avian diversity at both stand...

Arterial relationships to the nerves and some rigid structures in the posterior cranial fossa.

Science.gov (United States)

Surchev, N

2008-09-01

The close relationships between the cranial nerves and the arterial vessels in the posterior cranial fossa are one of the predisposing factors for artery-nerve compression. The aim of this study was to examine the relationships of the vertebral and basilar arteries to some skull and dural structures and the nerves in the posterior cranial fossa. For this purpose, the skull bases and brains of 70 cadavers were studied. The topographic relationships of the vertebral and basilar arteries to the cranial nerves in the posterior cranial fossa were studied and the distances between the arteries and some osseous formations were measured. The most significant variations in arterial position were registered in the lower half of the basilar artery. Direct contact with an artery was established for the hypoglossal canal, jugular tubercle, and jugular foramen. The results reveal additional information about the relationships of the nerves and arteries to the skull and dural formations in the posterior cranial fossa. New quantitative information is given to illustrate them. The conditions for possible artery-nerve compression due to arterial dislocation are discussed and two groups (lines) of compression points are suggested. The medial line comprises of the brain stem points, usually the nerve root entry/exit zone. The lateral line includes the skull eminences, on which the nerves lie, or skull and dural foramina through which they exit the cranial cavity. (c) 2008 Wiley-Liss, Inc.

Bonds or Bargains: Relationship Paradigms and Their Significance for Marital Therapy.

Science.gov (United States)

Johnson, Sue

1986-01-01

Discusses contrasting conceptual paradigms describing the nature of intimate relationships. Relationships may be viewed in terms of a rational bargain or as an emotional bond. The implications of each paradigm for the process of marital therapy and the role of bonding and attachment in adult intimacy are prescribed. Implications for marital…

V-amylose structural characteristics, methods of preparation, significance, and potential applications

CSIR Research Space (South Africa)

Obiro, WC

2012-02-01

Full Text Available , and postprandial hyperglycaemia in diabetics. Various aspects of V-amylose structure, methods of preparation, factors that affect its formation, and the significance and potential applications of the V-amylose complexes are reviewed....

Formation of cognitive structures in conditioned-reflex behavior in monkeys: Relationship with type of visual information.

Science.gov (United States)

Dudkin, K N; Chueva, I V

2009-02-01

The characteristics of learning processes and long-term memory (LTM) were studied in rhesus macaques discriminating visual stimuli (geometrical figures of different shapes, sizes, and orientations, and with different spatial relationships between image components). Trained monkeys were tested for the ability to perform invariant recognition after stimulus transformation, i.e., changes in size, shape, number of objects, and spatial relationships. Analysis of behavioral characteristics (correct solutions, refusals to decide, motor response times) revealed differences associated with the type of visual information. When monkeys discriminated between black and white geometrical figures of different shapes and orientations, as well as black-and-white figures with different shapes or orientations, the learning time was short and transformation of the stimuli had no effect on correct solutions: there was complete transfer of learning. When monkeys discriminated figures of different sizes or complex images with different spatial relationships, the learning time was significantly greater. Changes in the size and shape of figures led to significant reductions in correct solutions and significant increases in refusals to solve the task and in motor reaction times. Invariance of discrimination in this case appeared after additional training. The results obtained here showed that in conditioned reflex learning, the sensory processing of stimuli has the result that discriminatory features are formed in LTM, i.e., cognitive structures (functional neurophysiological mechanisms), these supporting the classification of visual images. The temporal conditioned link of the executive reaction is established with these. Their formation is determined by the type of sensory information and the existence in LTM of separate subsystems for spatial and non-spatial information.

Overnight weight loss: relationship with sleep structure and heart rate variability

OpenAIRE

Walter Moraes; Dalva Poyares; Christian Guilleminault; Agostinho Rosa; Marco Tulio Mello; Adriana Rueda; Sergio Tufik

2008-01-01

Background: Weight loss can be caused by a loss of body mass due to metabolism and by water loss as unsensible water loss, sweating, or excretion in feces and urine. Although weight loss during sleep is a well-known phenomenon, it has not yet been studied in relation to sleep structure or autonomic tonus during sleep. Our study is proposed to be a first step in assessing the relationship between overnight weight loss, sleep structure, and HRV (heart rate variability) parameters.Methods: Twent...

Stimulation of Orobanche ramosa seed germination by fusicoccin derivatives: a structure-activity relationship study.

Science.gov (United States)

Evidente, Antonio; Andolfi, Anna; Fiore, Michele; Boari, Angela; Vurro, Maurizio

2006-01-01

A structure-activity relationship study was conducted assaying 25 natural analogues and derivatives of fusicoccin (FC), and cotylenol, the aglycone of cotylenins, for their ability to stimulate the seed germination of the parasitic species Orobanche ramosa. Some of the compounds tested proved to be highly active, being 8,9-isopropylidene of the corresponding FC aglycone and the dideacetyl derivative the most active FC derivatives. In both groups of glucosides and aglycones (including cotylenol), the most important structural feature to impart activity appears to be the presence of the primary hydroxy group at C-19. Furthermore, the functionalities and the conformation of the carbotricyclic ring proved to play a significant role. The dideacetyl derivative of FC, being easily and rapidly obtainable in high yield starting by FC, could be of interest for its practical application as a stimulant of Orobanche ramosa seed germination, inducing the "suicidal germination", an interesting approach for parasitic plant management.

On the relationship between residue structural environment and sequence conservation in proteins.

Science.gov (United States)

Liu, Jen-Wei; Lin, Jau-Ji; Cheng, Chih-Wen; Lin, Yu-Feng; Hwang, Jenn-Kang; Huang, Tsun-Tsao

2017-09-01

Residues that are crucial to protein function or structure are usually evolutionarily conserved. To identify the important residues in protein, sequence conservation is estimated, and current methods rely upon the unbiased collection of homologous sequences. Surprisingly, our previous studies have shown that the sequence conservation is closely correlated with the weighted contact number (WCN), a measure of packing density for residue's structural environment, calculated only based on the C α positions of a protein structure. Moreover, studies have shown that sequence conservation is correlated with environment-related structural properties calculated based on different protein substructures, such as a protein's all atoms, backbone atoms, side-chain atoms, or side-chain centroid. To know whether the C α atomic positions are adequate to show the relationship between residue environment and sequence conservation or not, here we compared C α atoms with other substructures in their contributions to the sequence conservation. Our results show that C α positions are substantially equivalent to the other substructures in calculations of various measures of residue environment. As a result, the overlapping contributions between C α atoms and the other substructures are high, yielding similar structure-conservation relationship. Take the WCN as an example, the average overlapping contribution to sequence conservation is 87% between C α and all-atom substructures. These results indicate that only C α atoms of a protein structure could reflect sequence conservation at the residue level. © 2017 Wiley Periodicals, Inc.

Relationship among visual field, blood flow, and neural structure measurements in glaucoma.

Science.gov (United States)

Hwang, John C; Konduru, Ranjith; Zhang, Xinbo; Tan, Ou; Francis, Brian A; Varma, Rohit; Sehi, Mitra; Greenfield, David S; Sadda, Srinivas R; Huang, David

2012-05-17

To determine the relationship among visual field, neural structural, and blood flow measurements in glaucoma. Case-control study. Forty-seven eyes of 42 patients with perimetric glaucoma were age-matched with 27 normal eyes of 27 patients. All patients underwent Doppler Fourier-domain optical coherence tomography to measure retinal blood flow and standard glaucoma evaluation with visual field testing and quantitative structural imaging. Linear regression analysis was performed to analyze the relationship among visual field, blood flow, and structure, after all variables were converted to logarithmic decibel scale. Retinal blood flow was reduced in glaucoma eyes compared to normal eyes (P flow and structural loss of rim area and retinal nerve fiber layer (RNFL). There was no correlation or paradoxical correlation between blood flow and structure. Multivariate regression analysis revealed that reduced blood flow and structural loss are independent predictors of visual field loss. Each dB decrease in blood flow was associated with at least 1.62 dB loss in mean deviation (P ≤ 0.001), whereas each dB decrease in rim area and RNFL was associated with 1.15 dB and 2.56 dB loss in mean deviation, respectively (P ≤ 0.03). There is a close link between reduced retinal blood flow and visual field loss in glaucoma that is largely independent of structural loss. Further studies are needed to elucidate the causes of the vascular dysfunction and potential avenues for therapeutic intervention. Blood flow measurement may be useful as an independent assessment of glaucoma severity.

Doing the Organizational Tango: Symbiotic Relationship between Formal and Informal Organizational Structures for an Agile Organization

Directory of Open Access Journals (Sweden)

Irena Malgorzata Ali

2016-04-01

Full Text Available This paper reports on research with a broad objective to examine the relationship between two organizational entities, the formally structured organization and informal organizational structures, in a changing operational environment, more specifically during military deployments. The paper draws on organizational and complexity paradigms; based on empirical evidence obtained through qualitative techniques, it describes mechanisms that enable a symbiotic relationship between these two organizational structures in a complex operational landscape. Substantive findings provide insights into the dynamics of the interactions between these structures and illuminate the relationship between three enabling factors – accountability, responsible autonomy, and command and control arrangements – that need to be considered to fully exploit the strengths inherent in both formal and informal structures. Based on these findings, a model for enhancement of organizational agility in response to changes in a complex operational environment is described. The model is predicated on feedback and mutual adjustment of the organization, institution and individual through sensemaking; it illustrates the dynamic nature of interactions that are required for such a response.

Structure-activity relationships between sterols and their thermal stability in oil matrix.

Science.gov (United States)

Hu, Yinzhou; Xu, Junli; Huang, Weisu; Zhao, Yajing; Li, Maiquan; Wang, Mengmeng; Zheng, Lufei; Lu, Baiyi

2018-08-30

Structure-activity relationships between 20 sterols and their thermal stabilities were studied in a model oil system. All sterol degradations were found to be consistent with a first-order kinetic model with determination of coefficient (R 2 ) higher than 0.9444. The number of double bonds in the sterol structure was negatively correlated with the thermal stability of sterol, whereas the length of the branch chain was positively correlated with the thermal stability of sterol. A quantitative structure-activity relationship (QSAR) model to predict thermal stability of sterol was developed by using partial least squares regression (PLSR) combined with genetic algorithm (GA). A regression model was built with R 2 of 0.806. Almost all sterol degradation constants can be predicted accurately with R 2 of cross-validation equals to 0.680. Four important variables were selected in optimal QSAR model and the selected variables were observed to be related with information indices, RDF descriptors, and 3D-MoRSE descriptors. Copyright © 2018 Elsevier Ltd. All rights reserved.

An examination of a reciprocal relationship between network governance and network structure

DEFF Research Database (Denmark)

Bergenholtz, Carsten; Goduscheit, René Chester

The present article examines the network structure and governance of inter-organisational innovation networks. Network governance refers to the issue of how to manage and coordinate the relational activities and processes in the network while research on network structure deals with the overall...... structural relations between the actors in the network. These streams of research do contain references to each other but mostly rely on a static conception of the relationship between network structure and the applied network governance. The paper is based on a primarily qualitative case study of a loosely...... coupled Danish inter-organisational innovation network. The proposition is that a reciprocal relation between network governance and network structure can be identified....

Analysis of the relationships among trust antecedents, organizational structures, and performance outcomes

OpenAIRE

Seykora, Joseph T.

2009-01-01

Approved for public release, distribution unlimited MBA Professional Report The project explores and seeks to identify relationships among four trust antecedents, two organizational structures, and two performance outcomes. The results will help to further explain associations between trust level (high or low) and organizational structure. Past research found that the edge organization operating in a high trust environment produces the most accurate results in the least amount of time. ...

Three-dimensional quantitative structure-activity relationships and docking studies of some structurally diverse flavonoids and design of new aldose reductase inhibitors

Directory of Open Access Journals (Sweden)

Utpal Chandra De

2015-01-01

Full Text Available Aldose reductase (AR plays an important role in the development of several long-term diabetic complications. Inhibition of AR activities is a strategy for controlling complications arising from chronic diabetes. Several AR inhibitors have been reported in the literature. Flavonoid type compounds are shown to have significant AR inhibition. The objective of this study was to perform a computational work to get an idea about structural insight of flavonoid type compounds for developing as well as for searching new flavonoid based AR inhibitors. The data-set comprising 68 flavones along with their pIC 50 values ranging from 0.44 to 4.59 have been collected from literature. Structure of all the flavonoids were drawn in Chembiodraw Ultra 11.0, converted into corresponding three-dimensional structure, saved as mole file and then imported to maestro project table. Imported ligands were prepared using LigPrep option of maestro 9.6 version. Three-dimensional quantitative structure-activity relationships and docking studies were performed with appropriate options of maestro 9.6 version installed in HP Z820 workstation with CentOS 6.3 (Linux. A model with partial least squares factor 5, standard deviation 0.2482, R 2 = 0.9502 and variance ratio of regression 122 has been found as the best statistical model.

Chemistry and Structure-Activity Relationships of Psychedelics.

Science.gov (United States)

Nichols, David E

2018-01-01

This chapter will summarize structure-activity relationships (SAR) that are known for the classic serotonergic hallucinogens (aka psychedelics), focusing on the three chemical types: tryptamines, ergolines, and phenethylamines. In the brain, the serotonin 5-HT 2A receptor plays a key role in regulation of cortical function and cognition, and also appears to be the principal target for hallucinogenic/psychedelic drugs such as LSD. It is one of the most extensively studied of the 14 known types of serotonin receptors. Important structural features will be identified for activity and, where possible, those that the psychedelics have in common will be discussed. Because activation of the 5-HT 2A receptor is the principal mechanism of action for psychedelics, compounds with 5-HT 2A agonist activity generally are quickly discarded by the pharmaceutical industry. Thus, most of the research on psychedelics can be related to activation of 5-HT 2A receptors. Therefore, much of the discussion will include not only clinical or anecdotal studies, but also will consider data from animal models as well as a certain amount of molecular pharmacology where it is known.

Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins

Directory of Open Access Journals (Sweden)

Gheorghe Stan

2017-04-01

Full Text Available The exploitation of nanoscale size effects to create new nanostructured materials necessitates the development of an understanding of relationships between molecular structure, physical properties and material processing at the nanoscale. Numerous metrologies capable of thermal, mechanical, and electrical characterization at the nanoscale have been demonstrated over the past two decades. However, the ability to perform nanoscale molecular/chemical structure characterization has only been recently demonstrated with the advent of atomic-force-microscopy-based infrared spectroscopy (AFM-IR and related techniques. Therefore, we have combined measurements of chemical structures with AFM-IR and of mechanical properties with contact resonance AFM (CR-AFM to investigate the fabrication of 20–500 nm wide fin structures in a nanoporous organosilicate material. We show that by combining these two techniques, one can clearly observe variations of chemical structure and mechanical properties that correlate with the fabrication process and the feature size of the organosilicate fins. Specifically, we have observed an inverse correlation between the concentration of terminal organic groups and the stiffness of nanopatterned organosilicate fins. The selective removal of the organic component during etching results in a stiffness increase and reinsertion via chemical silylation results in a stiffness decrease. Examination of this effect as a function of fin width indicates that the loss of terminal organic groups and stiffness increase occur primarily at the exposed surfaces of the fins over a length scale of 10–20 nm. While the observed structure–property relationships are specific to organosilicates, we believe the combined demonstration of AFM-IR with CR-AFM should pave the way for a similar nanoscale characterization of other materials where the understanding of such relationships is essential.

Structure-affinity relationship in the interactions of human organic anion transporter 1 with caffeine, theophylline, theobromine and their metabolites.

Science.gov (United States)

Sugawara, Mitsuru; Mochizuki, Takahiro; Takekuma, Yoh; Miyazaki, Katsumi

2005-08-15

It is well known that human organic anion transporter 1 (hOAT1) transports many kinds of drugs, endogenous compounds, and toxins. However, little is known about the structure-affinity relationship. The aim of this study was to elucidate the structure-affinity relationship using a series of structurally related compounds that interact with hOAT1. Inhibitory effects of xanthine- and uric acid-related compounds on the transport of p-aminohippuric acid were examined using CHO-K1 cells stably expressing hOAT1. The order of potency for the inhibitory effects of xanthine-related compounds on PAH uptake was 1-methyl derivative>7-methyl derivative>3-methyl derivative falling dotsxanthine>1,3,7-trimethyl derivative (caffeine). The order of potency of the inhibition was 1,3,7-trimethyluric acid>1,3-dimethyluric acid>1,7-dimethyluric acid>1-methyluric acid>uric acid. A significant correlation between inhibitory potency and lipophilicity of the tested uric acid-related compounds was observed. The main determinant of the affinity of xanthine-related compounds is the position of the methyl group. On the other hand, lipophilicity is the main determinant of the affinity of uric acid-related compounds.

Structure-Property Relationships in Amorphous Transparent Conducting Oxides

Science.gov (United States)

Moffitt, Stephanie Lucille

Over the last 20 years a new field of amorphous transparent conducting oxides (a-TCOs) has developed. The amorphous nature of these films makes them well suited for large area applications. In addition, a-TCOs can be made at low temperatures and through solution processing methods. These assets provide promising opportunities to improve applications such as solar cells and back-lit displays where traditional crystalline TCOs are used. In addition, it opens the door for new technological applications including the possibility for transparent, flexible electronics. Despite the recent growth in this field, fundamental understanding of the true nature of conductivity and the amorphous structure in this materials system is still progressing. To develop a greater understanding of a-TCOs, structure-property relationships were developed in the a-IGO and a-IZO systems. From the combination of element-specific local structure studies and liquid quench molecular dynamics simulations it is clear that a degree of structure remains in a-TCOs. By understanding this structure, the effect of gallium on thermal stability, carrier concentration and carrier mobility is understood. The source of charge carriers in a-IZO is identified as oxygen vacancies through the application of in situ Brouwer analysis. The continued development of the Brouwer analysis technique for use in amorphous oxides adds to the available methods for studying defects in amorphous systems. Finally, the foundational knowledge gained from the in-depth study of a-IGO was extended to understand the role of combustion processing and pulsed laser deposition as growth methods for transistors based on a-IGO.

Power in a startup's relationships with its established partners : Interactions between structural and behavioural power

NARCIS (Netherlands)

Oukes, Tamara; von Raesfeld Meijer, Ariane; Groen, Aard

2017-01-01

Power plays a key role in the relationships between startups and established organisations. Yet researchers have devoted little attention to the startup's perspective on power in such relationships. To study startups' view on power, a useful starting point is their structural power, but this also

Relationships between the structure of wheat gluten and ACE inhibitory activity of hydrolysate: stepwise multiple linear regression analysis.

Science.gov (United States)

Zhang, Yanyan; Ma, Haile; Wang, Bei; Qu, Wenjuan; Wali, Asif; Zhou, Cunshan

2016-08-01

Ultrasound pretreatment of wheat gluten (WG) before enzymolysis can improve the angiotensin converting enzyme (ACE) inhibitory activity of the hydrolysates by alerting the structure of substrate proteins. Establishment of a relationship between the structure of WG and ACE inhibitory activity of the hydrolysates to judge the end point of the ultrasonic pretreatment is vital. The results of stepwise multiple linear regression (MLR) showed that the contents of free sulfhydryl, α-helix, disulfide bond, surface hydrophobicity and random coil were significantly correlated to ACE Inhibitory activity of the hydrolysate, with the standard partial regression coefficients were 3.729, -0.676, -0.252, 0.022 and 0.156, respectively. The R(2) of this model was 0.970. External validation showed that the stepwise MLR model could well predict the ACE inhibitory activity of hydrolysate based on the content of free sulfhydryl, α-helix, disulfide bond, surface hydrophobicity and random coil of WG before hydrolysis. A stepwise multiple linear regression model describing the quantitative relationships between the structure of WG and the ACE Inhibitory activity of the hydrolysates was established. This model can be used to predict the endpoint of the ultrasonic pretreatment. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Structure-function relationship between the octopus perimeter cluster mean sensitivity and sector retinal nerve fiber layer thickness measured with the RTVue optical coherence tomography and scanning laser polarimetry.

Science.gov (United States)

Naghizadeh, Farzaneh; Garas, Anita; Vargha, Péter; Holló, Gábor

2014-01-01

To determine structure-function relationship between each of 16 Octopus perimeter G2 program clusters and the corresponding 16 peripapillary sector retinal nerve fiber layer thickness (RNFLT) values measured with the RTVue-100 Fourier-domain optical coherence tomography (RTVue OCT) and scanning laser polarimetry with variable corneal compensation (GDx-VCC) and enhanced corneal compensation (GDx-ECC) corneal compensation. One eye of 110 white patients (15 healthy, 20 ocular hypertensive, and 75 glaucoma eyes) were investigated. The Akaike information criterion and the F test were used to identify the best fitting model. Parabolic relationship with logarithmic cluster mean sensitivity and linear sector RNFLT values provided the best fit. For RTVue OCT, significant (P0.05) was found for the control eyes. Mean sensitivity of the Octopus visual field clusters showed significant parabolic relationship with the corresponding peripapillary RNFLT sectors. The relationship was more general with the RTVue OCT than GDx-VCC or GDx-ECC. The results show that visual field clusters of the Octopus G program can be applied for detailed structure-function research.

Processing, structure, property and performance relationships for the thermal spray of the internal surface of aluminum cylinders

Science.gov (United States)

Cook, David James

The increased need for automotive weight reduction has necessitated the use of aluminum for engine blocks. Conventional aluminum alloys cannot survive the constant wear from a piston ring reciprocating on the surface. However, a wear resistant thermal spray coating can be applied on the internal surface of the cylinder bore, which has significant advantages over other available options. Thermal spray is a well-established process for depositing molten, semi-molten, or solid particles onto a substrate to form a protective coating. For this application, the two main challenges were obtaining good wear resistance, and achieving good adhesion. To design a system capable of producing a well-adhered, wear resistant coating for this high volume application it is necessary to identify the overall processing, structure, properties, and performance relationships. The results will demonstrate that very important relationships exist among particle characteristics, substrate conditions, and the properties of the final coating. However, it is the scientific studies to understand some of the process physics in these relationships that allow recognition of the critical processing conditions that need to be controlled to ensure a consistent, reliable thermal spray coating. In this investigation, it will be shown that the critical microstructural aspect of the coating that produced the required tribological properties was the presence of wuestite (FeO). It was found that by using a low carbon steel material with compressed air atomizing gas, it was possible to create an Fe/FeO structure that exhibited excellent tribological properties. This study will also show that traditional thermal spray surface preparation techniques were not ideal for this application, therefore a novel alternative approach was developed. The application of a flux to the aluminum surface prior to thermal spray promotes excellent bond strengths to non-roughened aluminum. Analysis will show that this flux strips

Applications of genetic algorithms on the structure-activity relationship analysis of some cinnamamides.

Science.gov (United States)

Hou, T J; Wang, J M; Liao, N; Xu, X J

1999-01-01

Quantitative structure-activity relationships (QSARs) for 35 cinnamamides were studied. By using a genetic algorithm (GA), a group of multiple regression models with high fitness scores was generated. From the statistical analyses of the descriptors used in the evolution procedure, the principal features affecting the anticonvulsant activity were found. The significant descriptors include the partition coefficient, the molar refraction, the Hammet sigma constant of the substituents on the benzene ring, and the formation energy of the molecules. It could be found that the steric complementarity and the hydrophobic interaction between the inhibitors and the receptor were very important to the biological activity, while the contribution of the electronic effect was not so obvious. Moreover, by construction of the spline models for these four principal descriptors, the effective range for each descriptor was identified.

Anti-proliferation activity of terpenoids isolated from Euphorbia kansui in human cancer cells and their structure-activity relationship.

Science.gov (United States)

Hou, Jin-Jun; Shen, Yao; Yang, Zhou; Fang, Lin; Cai, Lu-Ying; Yao, Shuai; Long, Hua-Li; Wu, Wan-Ying; Guo, De-An

2017-10-01

Euphorbia kansui is a commonly used traditional Chinese medicine for the treatment of edema, pleural effusion, and asthma, etc. According to the previous researches, terpenoids in E. kansui possess various biological activities, e.g., anti-virus, anti-allergy, antitumor effects. In this work, twenty five terpenoids were isolated from E. kansui, including thirteen ingenane- and eight jatrophane-type diterpenoids (with two new compounds, kansuinin P and Q) and four triterpenoids. Eighteen of them were analyzed by MTS assay for in vitro anticancer activity in five human cancer cell lines. Structure-activity relationship for 12 ingenane-type diterpenoids in colorectal cancer Colo205 cells were preliminary studied. Significant anti-proliferation activities were observed in human melanoma cells breast cancer MDA-MB-435 cells and Colo205 cells. More than half of the isolated ingenane-type diterpenoids showed inhibitory activities in MDA-MB-435 cells. Eight ingenane- and one jatrophane-type diterpenoids possessed much lower IC 50 values in MDA-MB-435 cells than positive control staurosporine. Preliminary structure-activity relationship analysis showed that substituent on position 20 was important for the activity of ingenane-type diterpenoids in Colo205 cells and substituent on position 3 contributed more significant biological activity of the compounds than that on position 5 in both MDA-MB-435 and Colo205 cells. Copyright © 2017 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Perceived boundary of 'differences' and 'sameness' by Japanese students in Australia : Is difference in cultures a significant variable for constructing interpersonal relationship?

OpenAIRE

小柳, 志津

2003-01-01

Thirty-one Japanese undergraduate and postgraduate students in Australian universities participated in semi-structured interviews to examine the interpersonal relationships between Japanese students and other nationalities in Australia, in particular, Australians and other international students. It was found that the Japanese students tended to form closer relationships and feel more comfortable in communicating with other Asian students than Australians, and that many regard Asian students ...

The relationship between occupational culture dimensions and reward preferences: A structural equation modelling approach

Directory of Open Access Journals (Sweden)

Mark Bussin

2016-06-01

Full Text Available Orientation: Reward has links to employee attraction and retention and as such has a role to play in managing talent. However, despite a range of research, there is still lack of clarity on employee preferences relating to reward. Research purpose: The purpose of the research was to recommend and appraise a theoretical model of the relationship between occupational culture dimensions and reward preferences of specific occupational groups in the South African context. Motivation for the study: The motivation for this study was to address the gap that exists with reward preferences and occupational culture with a view to identifying and gaining insight into individual preferences. Research design, approach and method: A structural equation modelling approach was adopted in exploring the proposed relationships. A South African Information, Communication, and Technology (ICT organisation served as the population, and a web-based survey assisted in gathering study data (n = 1362. Main findings: The findings provided support for the relationship between occupational culture dimensions and certain reward preferences. In particular, statistically significant results were obtained with the inclusion of the Environment, Team, and Time occupational culture dimensions as independent variables. Practical implications and value-add: The study provides workable input to organisations and reward professionals in the design of their reward strategies and programmes. Keywords: compensation; employee preferences; occupational culture; remuneration; reward preferences

Anosognosia in mild cognitive impairment: Relationship to activation of cortical midline structures involved in self-appraisal

Science.gov (United States)

Ries, Michele L.; Jabbar, Britta M.; Schmitz, Taylor W.; Trivedi, Mehul A.; Gleason, Carey E.; Carlsson, Cynthia M.; Rowley, Howard A.; Asthana, Sanjay; Johnson, Sterling C.

2009-01-01

Awareness of cognitive dysfunction shown by individuals with Mild Cognitive Impairment (MCI), a condition conferring risk for Alzheimer’s disease (AD), is variable. Anosognosia, or unawareness of loss of function, is beginning to be recognized as an important clinical symptom of MCI. However, little is known about the brain substrates underlying this symptom. We hypothesized that MCI participants’ activation of cortical midline structures (CMS) during self-appraisal would covary with level of insight into cognitive difficulties (indexed by a discrepancy score between patient and informant ratings of cognitive decline in each MCI participant). To address this hypothesis, we first compared 16 MCI participants and 16 age-matched controls, examining brain regions showing conjoint or differential BOLD response during self-appraisal. Second, we used regression to investigate the relationship between awareness of deficit in MCI and BOLD activity during self-appraisal, controlling for extent of memory impairment. Between-group comparisons indicated that MCI participants show subtly attenuated CMS activity during self-appraisal. Regression analysis revealed a highly-significant relationship between BOLD response during self-appraisal and self-awareness of deficit in MCI. This finding highlights the level of anosognosia in MCI as an important predictor of response to self-appraisal in cortical midline structures, brain regions vulnerable to changes in early AD. PMID:17445294

Synthesis and structure-activity relationship of N-alkyl Gly-boro-Pro inhibitors of DPP4, FAP, and DPP7.

Science.gov (United States)

Hu, Yi; Ma, Lifu; Wu, Min; Wong, Melissa S; Li, Bei; Corral, Sergio; Yu, Zhizhou; Nomanbhoy, Tyzoon; Alemayehu, Senaiet; Fuller, Stacy R; Rosenblum, Jonathan S; Rozenkrants, Natasha; Minimo, Lauro C; Ripka, William C; Szardenings, Anna K; Kozarich, John W; Shreder, Kevin R

2005-10-01

The structure-activity relationship of various N-alkyl Gly-boro-Pro derivatives against three dipeptidyl peptidases (DPPs) was studied. In a series of N-cycloalkyl analogs, DPP4 and fibroblast activation protein-alpha (FAP) optimally preferred N-cycloheptyl whereas DPP7 tolerated even larger cycloalkyl rings. Gly alpha-carbon derivatization of N-cyclohexyl or N-(2-adamantyl) Gly-boro-Pro resulted in a significant decrease in potency against all the three DPPs.

A biology-based approach for quantitative structure-activity relationships (QSARs) in ecotoxicity.

NARCIS (Netherlands)

Jager, T.; Kooijman, S.A.L.M.

2009-01-01

Quantitative structure-activity relationships (QSARs) for ecotoxicity can be used to fill data gaps and limit toxicity testing on animals. QSAR development may additionally reveal mechanistic information based on observed patterns in the data. However, the use of descriptive summary statistics for

Structure-Energy Relationships of Halogen Bonds in Proteins.

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Scholfield, Matthew R; Ford, Melissa Coates; Carlsson, Anna-Carin C; Butta, Hawera; Mehl, Ryan A; Ho, P Shing

2017-06-06

The structures and stabilities of proteins are defined by a series of weak noncovalent electrostatic, van der Waals, and hydrogen bond (HB) interactions. In this study, we have designed and engineered halogen bonds (XBs) site-specifically to study their structure-energy relationship in a model protein, T4 lysozyme. The evidence for XBs is the displacement of the aromatic side chain toward an oxygen acceptor, at distances that are equal to or less than the sums of their respective van der Waals radii, when the hydroxyl substituent of the wild-type tyrosine is replaced by a halogen. In addition, thermal melting studies show that the iodine XB rescues the stabilization energy from an otherwise destabilizing substitution (at an equivalent noninteracting site), indicating that the interaction is also present in solution. Quantum chemical calculations show that the XB complements an HB at this site and that solvent structure must also be considered in trying to design molecular interactions such as XBs into biological systems. A bromine substitution also shows displacement of the side chain, but the distances and geometries do not indicate formation of an XB. Thus, we have dissected the contributions from various noncovalent interactions of halogens introduced into proteins, to drive the application of XBs, particularly in biomolecular design.

Comparing the Structure-Function Relationship at the Macula With Standard Automated Perimetry and Microperimetry.

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Rao, Harsha L; Januwada, Manideepak; Hussain, Raza S M; Pillutla, Lalitha N; Begum, Viquar U; Chaitanya, Aditya; Senthil, Sirisha; Garudadri, Chandra S

2015-12-01

To compare the structure-function relationship between ganglion cell-inner plexiform layer (GCIPL) thickness measurements using spectral-domain optical coherence tomography (SDOCT) and visual sensitivities measured using standard automated perimetry (SAP) and microperimetry (MP) at the macula in glaucoma. In a prospective study, 45 control eyes (29 subjects) and 60 glaucoma eyes (45 patients) underwent visual sensitivity estimation at the macula (central 10°) by SAP and MP, and GCIPL thickness measurement at the macula by SDOCT. Structure-function relationships between GCILP thickness and visual sensitivity loss with SAP and MP at various macular sectors were assessed using the Hood and Kardon model. To compare structure-function relationship with SAP and MP, we calculated the number of data points falling outside the 5th and the 95th percentile values of the Hood and Kardon model with each of the perimeters. The number of points falling outside the 5th and 95th percentile values of the Hood and Kardon model ranged from 28 (superior sector) to 48 (inferonasal sector) with SAP and 33 (superior sector) to 49 (inferonasal sector) with MP. The difference in the number of points falling outside the 5th and 95th percentile values with SAP and MP was statistically insignificant (P > 0.05, χ(2) test) for all the sectors. Visual sensitivity measurements of both SAP and MP demonstrated a similar relationship with the GCIPL measurements of SDOCT at the macula in glaucoma.

Structural design significance of tension-tension fatigue data on composites

Science.gov (United States)

Grimes, G. C.

1977-01-01

Constant cycle tension-tension fatigue and related static tension data have been generated on six single composite material/orientation combinations and twenty-one hybrid composite material/orientation combinations. Anomalies are related to the temperature rise and stopped interval creep, whereas endurance limit stresses (runouts) are associated with static proportional limit values, when they occur, and internal damage. The significance of these room temperature-dry data on the design allowables and weight of aerodynamic structueres is discussed. Such structures are helicopter rotor blades and wing and horizontal stabilizer lower surfaces. Typical criteria for turning these data into preliminary allowables are shown, as are examples of such allowables developed from the data. These values are then compared to those that might be used if the structures were made of metal.

Antiplasmodial Activity, Cytotoxicity and Structure-Activity Relationship Study of Cyclopeptide Alkaloids

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Emmy Tuenter

2017-02-01

Full Text Available Cyclopeptide alkaloids are polyamidic, macrocyclic compounds, containing a 13-, 14-, or 15-membered ring. The ring system consists of a hydroxystyrylamine moiety, an amino acid, and a β-hydroxy amino acid; attached to the ring is a side chain, comprised of one or two more amino acid moieties. In vitro antiplasmodial activity was shown before for several compounds belonging to this class, and in this paper the antiplasmodial and cytotoxic activities of ten more cyclopeptide alkaloids are reported. Combining these results and the IC50 values that were reported by our group previously, a library consisting of 19 cyclopeptide alkaloids was created. A qualitative SAR (structure-activity relationship study indicated that a 13-membered macrocyclic ring is preferable over a 14-membered one. Furthermore, the presence of a β-hydroxy proline moiety could correlate with higher antiplasmodial activity, and methoxylation (or, to a lesser extent, hydroxylation of the styrylamine moiety could be important for displaying antiplasmodial activity. In addition, QSAR (quantitative structure-activity relationship models were developed, using PLS (partial least squares regression and MLR (multiple linear regression. On the one hand, these models allow for the indication of the most important descriptors (molecular properties responsible for the antiplasmodial activity. Additionally, predictions made for interesting structures did not contradict the expectations raised in the qualitative SAR study.

The relationship between inter-organizational trust and performance

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Roman Fiala

2012-01-01

Full Text Available The article deals with an investigation of the relationship between inter-organizational trust and performance. Using data obtained in a questionnaire survey in 373 organizations with more than 20 employees with their seat in the Czech Republic, we found the relationship between inter-organizational trust and supplier performance, mediated by the level of conflict. Also, the statistically significant negative relationship between inter-organizational trust and costs of negotiation and the statistically significant positive relationship between supplier performance and perceived performance were confirmed. The hypothesis on the statistically significant relationship between inter-organizational trust and negotiating costs was not confirmed. The structural equation modelling technique was used in the calculations. The calculated model fit indices (CFI, NFI, NNFI with values over 0.9 demonstrate a very good quality of the model.

Relationship between birth order of spouses with different degrees of consanguineous relationship.

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Reddy, B M; Malhotra, K C

1991-08-01

The relationship between birth order of spouses with different degrees of consanguinity is examined in a sample of 1826 couples belonging to the endogamous Vadde Fisherfolk of Kolleru Lake, Andhra Pradesh, India. We attempt to explain the wide variation in the frequency of different kinds of consanguineous marriages through the age-sex structure of the population in general and especially of the related families. This structure may also be manifested in the association between the birth orders of spouses. A highly significant and large correlation between the birth orders of spouses in uncle-niece marriages and a gradual decrease in the correlation with increase in remoteness of the relationship between the spouses were observed. Given the distribution of age differences between the spouses and assuming a standard age-sex structure, it seems possible to estimate the optimum frequency with which at least close consanguineous marriages occur in any particular population.

Significant relationship between lifetime alcohol use disorders and suicide attempts in an Australian schizophrenia sample.

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McLean, Duncan; Gladman, Beverley; Mowry, Bryan

2012-02-01

Suicide and attempted suicide are common in individuals with schizophrenia, and evidence exists for a link between substance use disorders and suicidality in this disorder. However, alcohol has not been consistently implicated. We examined the relationship between substance use disorders and suicide attempts in schizophrenia. We recruited a schizophrenia sample in Australia (n = 821) for genetic analyses. We analysed demographic and clinical variables, including substance use disorders, and their relationship to suicide attempts using generalised equation modelling. A significant association was identified between lifetime alcohol abuse/dependence and suicide attempts (OR = 1.66; 95% CI, 1.23 to 2.24; p = 0.001) after adjustment for potential confounders, but not between cannabis abuse/dependence and suicide attempts, nor between other illicit drug abuse/dependence and suicide attempts. Polysubstance abuse/dependence was also not implicated. These results suggest that the presence of alcohol abuse/dependence may be a risk factor for suicide attempts in individuals with schizophrenia, independent of comorbid substance abuse/dependence.

Comparison of Macular Integrity Assessment (MAIA ™, MP-3, and the Humphrey Field Analyzer in the Evaluation of the Relationship between the Structure and Function of the Macula.

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Kazuyuki Hirooka

Full Text Available This study was conducted in order to compare relationships between the macular visual field (VF mean sensitivity measured by MAIATM (Macular Integrity Assessment, MP-3, or Humphry field analyzer (HFA and the ganglion cell and inner plexiform layer (GCA thicknesses.This cross-sectional study examined 73 glaucoma patients and 19 normal subjects. All subjects underwent measurements for GCA thickness by Cirrus HD-OCT and static threshold perimetry using MAIATM, MP-3, or HFA. VF and OCT in the retinal view were used to examine both the global relationship between the VF sensitivity and GCA thickness, and the superior hemiretina and inferior hemiretina. The relationship between the GCA thickness and macular sensitivity was examined by Spearman correlation analysis.For each instrument, statistically significant macular VF sensitivity (dB and GCA thickness relationships were observed using the decibel scale (R = 0.547-0.687, all P < 0.001. The highest correlation for the global (R = 0.682 and the superior hemiretina (R = 0.594 GCA thickness-VF mean sensitivity was observed by the HFA. The highest correlation for the inferior hemiretina (R = 0.687 GCA thickness-VF mean sensitivity was observed by the MP-3. Among the three VF measurement instruments, however, no significant differences were found for the structure-function relationships.All three VF measurement instruments found similar structure-function relationships in the central VF.

The roles of host evolutionary relationships (genus: Nasonia) and development in structuring microbial communities.

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Brucker, Robert M; Bordenstein, Seth R

2012-02-01

The comparative structure of bacterial communities among closely related host species remains relatively unexplored. For instance, as speciation events progress from incipient to complete stages, does divergence in the composition of the species' microbial communities parallel the divergence of host nuclear genes? To address this question, we used the recently diverged species of the parasitoid wasp genus Nasonia to test whether the evolutionary relationships of their bacterial microbiotas recapitulate the Nasonia phylogenetic history. We also assessed microbial diversity in Nasonia at different stages of development to determine the role that host age plays in microbiota structure. The results indicate that all three species of Nasonia share simple larval microbiotas dominated by the γ-proteobacteria class; however, bacterial species diversity increases as Nasonia develop into pupae and adults. Finally, under identical environmental conditions, the relationships of the microbial communities reflect the phylogeny of the Nasonia host species at multiple developmental stages, which suggests that the structure of an animal's microbial community is closely allied with divergence of host genes. These findings highlight the importance of host evolutionary relationships on microbiota composition and have broad implications for future studies of microbial symbiosis and animal speciation. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Quantitative Structure – Antioxidant Activity Relationships of Flavonoid Compounds

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Károly Héberger

2004-12-01

Full Text Available A quantitative structure – antioxidant activity relationship (QSAR study of 36 flavonoids was performed using the partial least squares projection of latent structures (PLS method. The chemical structures of the flavonoids have been characterized by constitutional descriptors, two-dimensional topological and connectivity indices. Our PLS model gave a proper description and a suitable prediction of the antioxidant activities of a diverse set of flavonoids having clustering tendency.

Structure-activity relationships of diverse xanthones against multidrug resistant human tumor cells.

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Wang, Qiwen; Ma, Chenyao; Ma, Yun; Li, Xiang; Chen, Yong; Chen, Jianwei

2017-02-01

Thirteen xanthones were isolated naturally from the stem of Securidaca inappendiculata Hassk, and structure-activity relationships (SARs) of these compounds were comparatively predicted for their cytotoxic activity against three human multidrug resistant (MDR) cell lines MCF-7/ADR, SMMC-7721/Taxol, and A549/Taxol cells. The results showed that the selected xanthones exhibited different potent cytotoxic activity against the growth of different human tumor cell lines, and most of the xanthones exhibited selective cytotoxicity against SMMC-7721/Taxol cells. Furthermore, some tested xanthones showed stronger cytotoxicity than Cisplatin, which has been used in clinical application extensively. The SARs analysis revealed that the cytotoxic activities of diverse xanthones were affected mostly by the number and position of methoxyl and hydroxyl groups. Xanthones with more free hydroxyl and methoxyl groups increased the cytotoxic activity significantly, especially for those with the presence of C-3 hydroxyl and C-4 methoxyl groups. Copyright © 2016 Elsevier Ltd. All rights reserved.

Striving to be known by significant others: automatic activation of self-verification goals in relationship contexts.

Science.gov (United States)

Kraus, Michael W; Chen, Serena

2009-07-01

Extending research on the automatic activation of goals associated with significant others, the authors hypothesized that self-verification goals typically pursued with significant others are automatically elicited when a significant-other representation is activated. Supporting this hypothesis, the activation of a significant-other representation through priming (Experiments 1 and 3) or through a transference encounter (Experiment 2) led participants to seek feedback that verifies their preexisting self-views. Specifically, significant-other primed participants desired self-verifying feedback, in general (Experiment 1), from an upcoming interaction partner (Experiment 2), and relative to acquaintance-primed participants and favorable feedback (Experiment 3). Finally, self-verification goals were activated, especially for relational self-views deemed high in importance to participants' self-concepts (Experiment 2) and held with high certainty (Experiment 3). Implications for research on self-evaluative goals, the relational self, and the automatic goal activation literature are discussed, as are consequences for close relationships. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Noncoded amino acids in protein engineering: Structure-activity relationship studies of hirudin-thrombin interaction.

Science.gov (United States)

De Filippis, Vincenzo; Acquasaliente, Laura; Pontarollo, Giulia; Peterle, Daniele

2018-01-01

The advent of recombinant DNA technology allowed to site-specifically insert, delete, or mutate almost any amino acid in a given protein, significantly improving our knowledge of protein structure, stability, and function. Nevertheless, a quantitative description of the physical and chemical basis that makes a polypeptide chain to efficiently fold into a stable and functionally active conformation is still elusive. This mainly originates from the fact that nature combined, in a yet unknown manner, different properties (i.e., hydrophobicity, conformational propensity, polarizability, and hydrogen bonding capability) into the 20 standard natural amino acids, thus making difficult, if not impossible, to univocally relate the change in protein stability or function to the alteration of physicochemical properties caused by amino acid exchange(s). In this view, incorporation of noncoded amino acids with tailored side chains, allowing to finely tune the structure at a protein site, would facilitate to dissect the effects of a given mutation in terms of one or a few physicochemical properties, thus much expanding the scope of physical organic chemistry in the study of proteins. In this review, relevant applications from our laboratory will be presented on the use of noncoded amino acids in structure-activity relationships studies of hirudin binding to thrombin. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

3D Printers Can Provide an Added Dimension for Teaching Structure-Energy Relationships

Science.gov (United States)

Blauch, David N.; Carroll, Felix A.

2014-01-01

A 3D printer is used to prepare a variety of models representing potential energy as a function of two geometric coordinates. These models facilitate the teaching of structure-energy relationships in molecular conformations and in chemical reactions.

A phenomenological model for the structure-composition relationship of the high Tc cuprates based on simple chemical principles

International Nuclear Information System (INIS)

Alarco, J.A.; Talbot, P.C.

2012-01-01

A simple phenomenological model for the relationship between structure and composition of the high Tc cuprates is presented. The model is based on two simple crystal chemistry principles: unit cell doping and charge balance within unit cells. These principles are inspired by key experimental observations of how the materials accommodate large deviations from stoichiometry. Consistent explanations for significant HTSC properties can be explained without any additional assumptions while retaining valuable insight for geometric interpretation. Combining these two chemical principles with a review of Crystal Field Theory (CFT) or Ligand Field Theory (LFT), it becomes clear that the two oxidation states in the conduction planes (typically d 8 and d 9 ) belong to the most strongly divergent d-levels as a function of deformation from regular octahedral coordination. This observation offers a link to a range of coupling effects relating vibrations and spin waves through application of Hund’s rules. An indication of this model’s capacity to predict physical properties for HTSC is provided and will be elaborated in subsequent publications. Simple criteria for the relationship between structure and composition in HTSC systems may guide chemical syntheses within new material systems.

Investor structure and the price-volume relationship in a continuous double auction market: An agent-based modeling perspective

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Zhang, Wei; Bi, Zhengzheng; Shen, Dehua

2017-02-01

This paper investigates the impact of investor structure on the price-volume relationship by simulating a continuous double auction market. Connected with the underlying mechanisms of the price-volume relationship, i.e., the Mixture of Distribution Hypothesis (MDH) and the Sequential Information Arrival Hypothesis (SIAH), the simulation results show that: (1) there exists a strong lead-lag relationship between the return volatility and trading volume when the number of informed investors is close to the number of uninformed investors in the market; (2) as more and more informed investors entering the market, the lead-lag relationship becomes weaker and weaker, while the contemporaneous relationship between the return volatility and trading volume becomes more prominent; (3) when the informed investors are in absolute majority, the market can achieve the new equilibrium immediately. Therefore, we can conclude that the investor structure is a key factor in affecting the price-volume relationship.

Structure-properties relationships of polyhedral oligomeric silsesquioxane (POSS filled PS nanocomposites

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J. J. Schwab

2012-07-01

Full Text Available The polyhedral oligomeric silsesquioxane (POSS additivated polystyrene (PS based nanocomposites were prepared by melt processing and the structure-properties relationships of the POSS-PS systems were compared to those of the neat PS. In order to investigate the effect of these structural parameters on the final properties of the polymer nanocomposites, five different kinds of POSS samples were used, in particular, POSS with different inorganic cage and with different organic pendent groups. The rheological investigation suggests clearly that the POSS acts as a plasticizer and that the processability of the PS was positively modified. The affinity between the POSS samples and the PS matrix was estimated by the calculated theoretical solubility parameters, considering the Hoy’s method and by morphology analysis. Minor difference between the solubility parameter of POSS and the matrix means better compatibility and no aggregation tendency. Furthermore, the POSS loading leads to a decrease of the rigidity, of the glass transition temperature and of the damping factor of the nanocomposite systems. The loading of different POSS molecules with open cage leads to a more pronounced effect on all the investigated properties that the loading of the POSS molecules with closed cage. Moreover, the melt properties are significantly influenced by the type of inorganic framework, by the type of the pendent organic groups and by the interaction between the POSS organic groups and the host matrix, while, the solid state properties appears to be influenced more by the kind of cage.

Synthesis and structure-activity relationship exploration of some potent anti-cancer phenyl amidrazone derivatives.

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Habashneh, Almeqdad Y; El-Abadelah, Mustafa M; Bardaweel, Sanaa K; Taha, Mutasem O

2017-12-04

Amidrazones have been reported to have significant anti-tumor properties against several cancer cell lines. The current project aims to profile the structure-anticancer activity relationship of phenyl-amidrazons. Fifteen phenyl-amidrazone-piperazine derivatives were prepared and tested against four cancer cell lines (leukemia, prostate, breast and colon cancers). Six compounds illustrated low micromolar anticancer IC50 values, while the remaining compounds were either inactive or of moderate potencies. All compounds were virtually nontoxic against normal fibroblast cells. Docking into the oncogenic kinase bcr/abl illustrated the critical importance of (i) p-halogen substituent on the ligand's phenyl ring and (ii) the presence of positive ionizable moiety at the ligand's piperazine fragment for anticancer activity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Structure-rheology relationship in a sheared lamellar fluid.

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Jaju, S J; Kumaran, V

2016-03-01

The structure-rheology relationship in the shear alignment of a lamellar fluid is studied using a mesoscale model which provides access to the lamellar configurations and the rheology. Based on the equations and free energy functional, the complete set of dimensionless groups that characterize the system are the Reynolds number (ργL(2)/μ), the Schmidt number (μ/ρD), the Ericksen number (μγ/B), the interface sharpness parameter r, the ratio of the viscosities of the hydrophilic and hydrophobic parts μ(r), and the ratio of the system size and layer spacing (L/λ). Here, ρ and μ are the fluid density and average viscosity, γ is the applied strain rate, D is the coefficient of diffusion, B is the compression modulus, μ(r) is the maximum difference in the viscosity of the hydrophilic and hydrophobic parts divided by the average viscosity, and L is the system size in the cross-stream direction. The lattice Boltzmann method is used to solve the concentration and momentum equations for a two dimensional system of moderate size (L/λ=32) and for a low Reynolds number, and the other parameters are systematically varied to examine the qualitative features of the structure and viscosity evolution in different regimes. At low Schmidt numbers where mass diffusion is faster than momentum diffusion, there is fast local formation of randomly aligned domains with "grain boundaries," which are rotated by the shear flow to align along the extensional axis as time increases. This configuration offers a high resistance to flow, and the layers do not align in the flow direction even after 1000 strain units, resulting in a viscosity higher than that for an aligned lamellar phase. At high Schmidt numbers where momentum diffusion is fast, the shear flow disrupts layers before they are fully formed by diffusion, and alignment takes place by the breakage and reformation of layers by shear, resulting in defects (edge dislocations) embedded in a background of nearly aligned layers

The relationships of multiple factors to menopausal symptoms in different racial/ethnic groups of midlife women: the structural equation modeling.

Science.gov (United States)

Im, Eun-Ok; Chang, Sun Ju; Chee, Eunice; Chee, Wonshik

2018-04-09

The purpose of the present study was to examine the relationships of multiple factors to menopausal symptoms in different racial/ethnic groups of midlife women. This secondary analysis was conducted with the data from 980 midlife women that were collected from 2005 to 2013 using the Midlife Women's Symptom Index. Structural equation modeling was used to analyze the data. The model had the highest fit indices for Non-Hispanic (NH) White midlife women, and prominent racial/ethnic differences were observed in the relationships of multiple factors to menopausal symptoms. In all racial/ethnic groups (except in Hispanic women), perceived health status was significantly associated positively with menopausal symptoms (β = -0.149 for NH African American; β = -0.207 for NH Asians; β = -0.162 for NH Whites). Body mass index was significantly positively associated with menopausal symptoms only in NH Asians (β = 0.118) and Hispanics (β = 0.210). The racial/ethnic differences in the relationships of multiple factors to menopausal symptoms could have resulted from the different cultural contexts in which women undergo during their menopausal transitions. Further cultural studies on the associations of racial/ethnic-specific factors with menopausal symptoms would help in understanding possible causes for racial/ethnic differences in the factors significantly associated with menopausal symptoms.

Quantitative description on structure-property relationships of Li-ion battery materials for high-throughput computations

Science.gov (United States)

Wang, Youwei; Zhang, Wenqing; Chen, Lidong; Shi, Siqi; Liu, Jianjun

2017-12-01

Li-ion batteries are a key technology for addressing the global challenge of clean renewable energy and environment pollution. Their contemporary applications, for portable electronic devices, electric vehicles, and large-scale power grids, stimulate the development of high-performance battery materials with high energy density, high power, good safety, and long lifetime. High-throughput calculations provide a practical strategy to discover new battery materials and optimize currently known material performances. Most cathode materials screened by the previous high-throughput calculations cannot meet the requirement of practical applications because only capacity, voltage and volume change of bulk were considered. It is important to include more structure-property relationships, such as point defects, surface and interface, doping and metal-mixture and nanosize effects, in high-throughput calculations. In this review, we established quantitative description of structure-property relationships in Li-ion battery materials by the intrinsic bulk parameters, which can be applied in future high-throughput calculations to screen Li-ion battery materials. Based on these parameterized structure-property relationships, a possible high-throughput computational screening flow path is proposed to obtain high-performance battery materials.

Structure of Unsteady Partially Premixed Flames and the Existence of State Relationships

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Suresh K. Aggarwal

2009-09-01

essentially similar in the second regime. A more significant difference in the first regime between these flames is the presence of a flow instability that manifests itself through the self-excited oscillations of the 1-g flame and the concomitant flickering of the nonpremixed reaction zone. For VR ≤ 1, as the coflow velocity is increased, the oscillation amplitude decreases and the oscillation frequency increases, both of which are in accord with previous experimental and computational results concerning 1-g jet diffusion flames. The modified conserved scalar approach is found to be effective in characterizing the flame structure and developing state relationships for both steady and unsteady partially premixed flames. This is demonstrated by the fact that the temperature as well as the major and minor species profiles follow similar state relationships in terms of the modified mixture fraction for the 0- and 1-g flames, even though these flames have markedly different spatio-temporal characteristics.

Evolutionary significance of seed structure in Alpinioideae (Zingiberaceae): Seed Structure in Alpinioideae

Energy Technology Data Exchange (ETDEWEB)

Benedict, John C. [Department of Earth & Environmental Sciences, University of Michigan, Ann Arbor MI (United States); Smith, Selena Y. [Department of Earth & Environmental Sciences, University of Michigan, Ann Arbor MI (United States); Museum of Paleontology, University of Michigan, Ann Arbor MI (United States); Collinson, Margaret E. [Department of Earth Sciences, Royal Holloway, University of London (United Kingdom); Leong-Škorničková, Jana [Herbarium, Singapore Botanic Gardens, National Parks Board (Singapore); Specht, Chelsea D. [Department of Plant and Microbial Biology & University and Jepson Herbaria, University of California, Berkeley CA (United States); Fife, Julie L. [Swiss Light Source, Paul Scherrer Institut, Villigen (Switzerland); Marone, Federica [Swiss Light Source, Paul Scherrer Institut, Villigen (Switzerland); Xiao, Xianghui [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Parkinson, Dilworth Y. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)

2015-03-09

Alpinioideae is the largest of the four subfamilies of Zingiberaceae and is widely distributed throughout the New and Old World tropics. Recent molecular studies have shown that, although Alpinioideae is a strongly supported monophyletic subfamily with two distinct tribes (Alpinieae and Riedelieae), large genera, such as Alpinia and Amomum, are polyphyletic and are in need of revision. Alpinia and Amomum have been shown to form seven and three distinct clades, respectively, but, for many of these clades, traditional vegetative and floral synapomorphies have not been found. A broad survey of seeds in Alpinioideae using light microscopy and synchrotron-based X-ray tomographic microscopy has shown that many clades have distinctive seed structures that serve as distinctive apomorphies. Tribes Riedelieae and Alpinieae can be distinguished on the basis of operculum structure, with the exception of three taxa analysed. The most significant seed characters were found to be various modifications of the micropylar and chalazal ends, the cell shape of the endotesta and exotesta, and the location of an endotestal gap. A chalazal chamber and hilar rim are reported for the first time in Zingiberaceae. In addition to characterizing clades of extant lineages, these data offer insights into the taxonomic placement of many fossil zingiberalean seeds that are critical to understanding the origin and evolution of Alpinioideae and Zingiberales as a whole.(c) 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178, 441-466..

Study of relationship between the organizational structure and market orientation from the viewpoint of nurse managers.

Science.gov (United States)

Bahadori, Mohammadkarim; Yaghoubi, Maryam; Javadi, Marzieh; Rahimi, Zahreh Agha

2015-01-01

Considering globalization of health care and quality improvement trend to respond to competition and customer orientation, attention to organizational structure and its relationship with market orientation is essential. Therefore, this study reviews the relationship between organizational structure and market orientation in selected hospitals of Isfahan (Iran). This study was a descriptive survey. The study population comprised nurse managers from selected hospitals (n = 80). Data collection tools were two questionnaires (market orientation questionnaire and organizational structure) that the validity and reliability were confirmed (r = 0.83 for market orientation questionnaire and r = 0.87 for organizational structure). SPSS (Ver. 16) software was used for the analyses. The mean score of organizational structure was 65.4 (11.2) and total mean of market orientation was 51.14 (17.6). All aspects of the organizational structure (Organization Centralization, Formalization in Organization, and Organization Complication) and market orientation (responding to competition, accountability, customer satisfaction, intelligent organization)-except by responding to clients with Formalization in Organization-as well as all aspects of the Systemic attitude (the system of internal coordination and communication systems_ and market orientation (responding to competition, accountability, customer satisfaction, intelligent organization), there was a meaningful relationship (P organizational structure and can lead managers' view to the analysis and recognizing elements of success and achievement to goals. With increasing competition in markets, globalization of health services, and presence in international markets and more attention to patients' satisfaction, hospitals need to understand and use of market orientation in order to promote quality and services in the health care system.

The Effect of Relationship Marketing towards Customers' Loyalty Mediated by Relationship Quality (Case Study in Priority Bank in Niaga

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Endang Ruswanti

2016-10-01

Full Text Available A large number of banks let people be more free in choosing the best bank for their needs. People can freely switch from one bank to another which makes the loyalty level of bank customers decrease, even though the efforts and cost spent for maintaining the customers is cheaper than the efforts and cost spent on getting new customers. Relationship is one of the answers to the problem, relationship marketing is a marketing principle which emphasizes and takes effort in maintaining good long term relationship with customers. This research aims to, analyze the influence competence, communication, and conflict handling towards relationship quality, mediated by relationship quality, and towards customer loyalty. The research was conducted by collecting quantitative data through questionnaires distributed to 130 respondents. The objects of this research were the priority customers at Niaga Bank, and it used purposive sampling technique. This research conducted by using Structural Equation Model method. The result of this research showed that, (1 relationship marketing which consists of competence component, communication, and conflict handling have significant influence and positively towards relationship quality, partially and simultaneously, (2 relationship marketing have significant influence and positively towards customer loyalty which is mediated by relationship quality, and (3 relationship quality have significant influence and positively towards customer loyalty.

The Relationship between Structure-Related Food Parenting Practices and Children's Heightened Levels of Self-Regulation in Eating.

Science.gov (United States)

Frankel, Leslie A; Powell, Elisabeth; Jansen, Elena

Food parenting practices influence children's eating behaviors and weight status. Food parenting practices also influence children's self-regulatory abilities around eating, which has important implications for children's eating behaviors. The purpose of the following study is to examine use of structure-related food parenting practices and the potential impact on children's ability to self-regulate energy intake. Parents (n = 379) of preschool age children (M = 4.10 years, SD = 0.92) were mostly mothers (68.6%), Non-White (54.5%), and overweight/obese (50.1%). Hierarchical Multiple Regression was conducted to predict child self-regulation in eating from structure-related food parenting practices (structured meal setting, structured meal timing, family meal setting), while accounting for child weight status, parent age, gender, BMI, race, and yearly income. Hierarchical Multiple Regression results indicated that structure-related feeding practices (structured meal setting and family meal setting, but not structured meal timing) are associated with children's heightened levels of self-regulation in eating. Models examining the relationship within children who were normal weight and overweight/obese indicated the following: a relationship between structured meal setting and heightened self-regulation in eating for normal-weight children and a relationship between family meal setting and heightened self-regulation in eating for overweight/obese children. Researchers should further investigate these potentially modifiable parent feeding behaviors as a protective parenting technique, which possibly contributes to a healthy weight development by enhancing self-regulation in eating.

Scale-Free Relationships between Social and Landscape Factors in Urban Systems

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Chunzhu Wei

2017-01-01

Full Text Available Urban planners and ecologists have long debated the relationship between the structure of urban landscapes and social activities. There have, however, been very few discussions as to whether any such relationships might depend on the scales of observation. This work applies a hierarchical zoning technique to data from the city of Quito, Ecuador, to examine how relationships between typical spatial landscape metrics and social indicators depend on zoning scales. Our results showed that the estimates of both landscape heterogeneity features and social indicators significantly depend on the zoning scale. The mean values of the typical landscape metrics and the social indicators all exhibited predictable responses to a changing zoning scale, suggesting a consistent and significant scaling relationship within the multiple zoning scales. Yet relationships between these pairs of variables remain notably invariant to scale. This quantitative demonstration of the scale-free nature of the relationship between landscape characteristics and social indicators furthers our understanding of the relationships between landscape structures and social aspects of urban spaces, including deprivation and public service accessibility. The relationships between social indicators and one typical landscape aggregation metric (represented as the percentage of like adjacencies were nevertheless significantly dependent on scale, suggesting the importance of zoning scale decisions for analyzing the relationships between the social indicators and the landscape characteristics related with landscape adjacency. Aside from this typical landscape aggregation metric, the general invariance to the zoning scale of relationships between landscape structures and socioeconomic indicators in Quito suggests the importance of applying these scale-free relationships in understanding complex socio-ecological systems in other cities, which are shaped by the conflated influences of both

Structure-thermodynamics-antioxidant activity relationships of selected natural phenolic acids and derivatives: an experimental and theoretical evaluation.

Science.gov (United States)

Chen, Yuzhen; Xiao, Huizhi; Zheng, Jie; Liang, Guizhao

2015-01-01

Phenolic acids and derivatives have potential biological functions, however, little is known about the structure-activity relationships and the underlying action mechanisms of these phenolic acids to date. Herein we investigate the structure-thermodynamics-antioxidant relationships of 20 natural phenolic acids and derivatives using DPPH• scavenging assay, density functional theory calculations at the B3LYP/6-311++G(d,p) levels of theory, and quantitative structure-activity relationship (QSAR) modeling. Three main working mechanisms (HAT, SETPT and SPLET) are explored in four micro-environments (gas-phase, benzene, water and ethanol). Computed thermodynamics parameters (BDE, IP, PDE, PA and ETE) are compared with the experimental radical scavenging activities against DPPH•. Available theoretical and experimental investigations have demonstrated that the extended delocalization and intra-molecular hydrogen bonds are the two main contributions to the stability of the radicals. The C = O or C = C in COOH, COOR, C = CCOOH and C = CCOOR groups, and orthodiphenolic functionalities are shown to favorably stabilize the specific radical species to enhance the radical scavenging activities, while the presence of the single OH in the ortho position of the COOH group disfavors the activities. HAT is the thermodynamically preferred mechanism in the gas phase and benzene, whereas SPLET in water and ethanol. Furthermore, our QSAR models robustly represent the structure-activity relationships of these explored compounds in polar media.

Multi-Structural Relationships among Organizational Culture, Job Autonomy, and CTE Teacher Turnover Intention

Science.gov (United States)

Song, Ji Hoon; Martens, Jon; McCharen, Belinda; Ausburn, Lynna J.

2011-01-01

This study investigated structural relationships among the constructs of supportive learning culture, school innovative climate, task-related job autonomy, and teacher turnover intention in career and technical education. The study applied organizational concepts to a problem typically approached from the perspective of teacher characteristics and…

Significance of agricultural row structure on the microwave emissivity of soils

Science.gov (United States)

Promes, P. M.; Jackson, T. J.; O'Neill, P. E.

1987-01-01

A series of field experiments was carried out to extend the data base available for verifying agricultural row effect models of emissivity. The row effects model was used to simulate a data base from which an algorithm could be developed to account for row effects when the scene dielectric constant and small-scale roughness are unknown. One objective of the study was to quantify the significance of row structure and to develop a practical procedure for removing the effects of periodic row structure on the microwave emissivity of a soil in order to use the emissivity values to estimate the soil moisture. A second objective was to expand the data set available for model verification through field observations using a truck-mounted 1.4-GHz microwave radiometer.

Quantitative structure-retention relationships of flavonoids unraveled by immobilized artificial membrane chromatography.

Science.gov (United States)

Santoro, Adriana Leandra; Carrilho, Emanuel; Lanças, Fernando Mauro; Montanari, Carlos Alberto

2016-06-10

The pharmacokinetic properties of flavonoids with differing degrees of lipophilicity were investigated using immobilized artificial membranes (IAMs) as the stationary phase in high performance liquid chromatography (HPLC). For each flavonoid compound, we investigated whether the type of column used affected the correlation between the retention factors and the calculated octanol/water partition (log Poct). Three-dimensional (3D) molecular descriptors were calculated from the molecular structure of each compound using i) VolSurf software, ii) the GRID method (computational procedure for determining energetically favorable binding sites in molecules of known structure using a probe for calculating the 3D molecular interaction fields, between the probe and the molecule), and iii) the relationship between partition and molecular structure, analyzed in terms of physicochemical descriptors. The VolSurf built-in Caco-2 model was used to estimate compound permeability. The extent to which the datasets obtained from different columns differ both from each other and from both the calculated log Poct and the predicted permeability in Caco-2 cells was examined by principal component analysis (PCA). The immobilized membrane partition coefficients (kIAM) were analyzed using molecular descriptors in partial least square regression (PLS) and a quantitative structure-retention relationship was generated for the chromatographic retention in the cholesterol column. The cholesterol column provided the best correlation with the permeability predicted by the Caco-2 cell model and a good fit model with great prediction power was obtained for its retention data (R(2)=0.96 and Q(2)=0.85 with four latent variables). Copyright © 2015 Elsevier B.V. All rights reserved.

New insights about enzyme evolution from large scale studies of sequence and structure relationships

OpenAIRE

Babbitt, Patricia; Brown, SD; Babbitt, PC

2014-01-01

© 2014 by The American Society for Biochemistry and Molecular Biology, Inc.Understanding how enzymes have evolved offers clues about their structure-function relationships and mechanisms. Here, we describe evolution of functionally diverse enzyme superfami

Quantitative structure-retention relationships of pesticides in reversed-phase high-performance liquid chromatography

International Nuclear Information System (INIS)

Aschi, Massimiliano; D'Archivio, Angelo Antonio; Maggi, Maria Anna; Mazzeo, Pietro; Ruggieri, Fabrizio

2007-01-01

In this paper, a quantitative structure-retention relationships (QSRR) method is employed to predict the retention behaviour of pesticides in reversed-phase high-performance liquid chromatography (HPLC). A six-parameter nonlinear model is developed by means of a feed-forward artificial neural network (ANN) with back-propagation learning rule. Accurate description of the retention factors of 26 compounds including commonly used insecticides, herbicides and fungicides and some metabolites is successfully achieved. In addition to the acetonitrile content, included to describe composition of the water-acetonitrile mobile phase, the octanol-water partition coefficient (from literature) and four quantum chemical descriptors are considered to account for the effect of solute structure on the retention. These are: the total dipole moment, the mean polarizability, the anisotropy of polarizability and a descriptor of hydrogen bonding ability based on the atomic charges on hydrogen bond donor and acceptor chemical functionalities. The proposed nonlinear QSRR model exhibits a high degree of correlation between observed and computed retention factors and a good predictive performance in wide range of mobile phase composition (40-65%, v/v acetonitrile) that supports its application for the prediction of the chromatographic behaviour of unknown pesticides. A multilinear regression model based on the same six descriptors shows a significantly worse predictive capability

Quantitative structure-retention relationships of pesticides in reversed-phase high-performance liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Aschi, Massimiliano [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); D' Archivio, Angelo Antonio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy)]. E-mail: darchivi@univaq.it; Maggi, Maria Anna [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); Mazzeo, Pietro [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); Ruggieri, Fabrizio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy)

2007-01-23

In this paper, a quantitative structure-retention relationships (QSRR) method is employed to predict the retention behaviour of pesticides in reversed-phase high-performance liquid chromatography (HPLC). A six-parameter nonlinear model is developed by means of a feed-forward artificial neural network (ANN) with back-propagation learning rule. Accurate description of the retention factors of 26 compounds including commonly used insecticides, herbicides and fungicides and some metabolites is successfully achieved. In addition to the acetonitrile content, included to describe composition of the water-acetonitrile mobile phase, the octanol-water partition coefficient (from literature) and four quantum chemical descriptors are considered to account for the effect of solute structure on the retention. These are: the total dipole moment, the mean polarizability, the anisotropy of polarizability and a descriptor of hydrogen bonding ability based on the atomic charges on hydrogen bond donor and acceptor chemical functionalities. The proposed nonlinear QSRR model exhibits a high degree of correlation between observed and computed retention factors and a good predictive performance in wide range of mobile phase composition (40-65%, v/v acetonitrile) that supports its application for the prediction of the chromatographic behaviour of unknown pesticides. A multilinear regression model based on the same six descriptors shows a significantly worse predictive capability.

Structure-Property Relationships and the Mixed Network Former Effect in Boroaluminosilicate Glasses

DEFF Research Database (Denmark)

Zheng, Qiuju; Potuzak, Marcel; Mauro, John C.

compositions by substituting Al2O3 for SiO2. We also investigate the various roles of sodium in the glasses including charge compensation of tetrahedral aluminum and boron atoms and formation of non-bridging oxygen. We find that mechanical properties (density, elastic moduli, and hardness), glass transition......Boroaluminosilicate glasses are important materials for various applications, e.g., liquid crystal display substrates, glass fibers for reinforcement, and thermal shock-resistant glass containers. The complicated structural speciation in these glasses leads to a mixed network former effect yielding...... nonlinear variation in many macroscopic properties. It is therefore crucial to investigate and understand structure-property correlations in boroaluminosilicate glasses. Here we study the structure-property relationships of a range of sodium boroaluminosilicate glasses from peralkaline to peraluminous...

Absorbability, Mechanism and Structure-Property Relationship of Three Phenolic Acids from the Flowers of Trollius chinensis

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Xiu-Wen Wu

2014-11-01

Full Text Available The absorption properties, mechanism of action, and structure-property relationship of three phenolic acids isolated from the flowers of Trollius chinensis Bunge, namely, proglobeflowery acid (PA, globeflowery acid (GA and trolloside (TS, were investigated using the human Caco-2 cell monolayer model. The results showed that these three phenolic acids were transported across the Caco-2 cell monolayer in a time and concentration dependent manner at the Papp level of 10−5 cm/s, and their extent of absorption correlated with their polarity and molecular weight. In conclusion, all three of these compounds were easily absorbed through passive diffusion, which implied their high bioavailability and significant contribution to the effectiveness of T. chinensis.

Establishing collaborative structures and relationships: Teacher leaders' experiences

Science.gov (United States)

Canizo, Thea Lynne

2002-04-01

The purpose of this study was to explore teacher leaders' experiences as they attempted to establish collaborative structures and relationships resulting in improved science instruction at their schools. Teacher leaders were middle school science facilitators, full-time classroom teachers who acted as liaisons between the science teachers at their schools and a change initiative funded by the National Science Foundation. This was a qualitative study, using interviews to create a case study. The researcher used a three-part interview design developed by Seidman (1991). Six research questions served as a framework for the data analysis. Participants identified the following as factors which contributed to their success: support from the principal, other science teachers, central staff personnel, and the district-wide group of science facilitators; professional development; and the successful completion of a scope and sequence for science instruction. Factors identified as hindering their success were: lack of support or conflict with the principal; resistance to change; time constraints; a district policy which limited meeting time; teacher and administrator turnover; tension between the middle school and junior high school models; and personal doubts. From descriptions of their understanding and exercising of leadership, the researcher concluded that teacher leaders had become empowered. The school culture was seen to have a great effect on teacher leaders. The contrasts between a school with a positive culture and another school in disarray were presented. Structures such as summer institutes and release time during the school day were identified as critical for giving teachers the time needed to establish more collaborative working relationships. Once greater trust and understanding were present, teachers were better able to examine their teaching practices more critically. Participants identified mentoring of new members, a continuing role for science

Structure-Activity Relationships on the Molecular Descriptors Family Project at the End

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Lorentz JÄNTSCHI

2007-12-01

Full Text Available Molecular Descriptors Family (MDF on the Structure-Activity Relationships (SAR, a promising approach in investigation and quantification of the link between 2D and 3D structural information and the activity, and its potential in the analysis of the biological active compounds is summarized. The approach, attempts to correlate molecular descriptors family generated and calculated on a set of biological active compounds with their observed activity. The estimation as well as prediction abilities of the approach are presented. The obtained MDF SAR models can be used to predict the biological activity of unknown substrates in a series of compounds.

Structural Relationships among E-Learners' Sense of Presence, Usage, Flow, Satisfaction, and Persistence

Science.gov (United States)

Joo, Young Ju; Joung, Sunyoung; Kim, Eun Kyung

2013-01-01

This study aimed to investigate the structural relationships among teaching presence, cognitive presence, usage, learning flow, satisfaction, and learning persistence in corporate e-learners. The research participants were 462 e-learners registered for cyber-lectures through an electronics company in South Korea. The extrinsic variables were sense…

Environmental properties of long-chain alcohols. Structure-activity Relationship for Chronic Aquatic Toxicity

DEFF Research Database (Denmark)

Schaefers, Christoph; Sanderson, Hans; Boshof, Udo

2009-01-01

Daphnia magna reproduction tests were performed with C10, C12, C14 and C15 alcohols to establish a structure-activity relationship of chronic effects of long-chain alcohols. The data generation involved substantial methodological efforts due to the exceptionally rapid biodegradability of the test...

Factor Structure of the Chinese Version of the Parent Adult-Child Relationship Questionnaire

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Daoyang Wang

2018-03-01

Full Text Available The Parent Adult-Child Relationship Questionnaire (PACQ included two identical versions of the 13-item scale, which were administered to each subject, one which referred to “relationship with mother” and the other to “relationship with father.” The PACQ, originally in English, is a self-report measure of the filial relationship. The present study aimed to develop a Chinese version of the PACQ and use it to explore Chinese parent adult-child relationships. A total of 454 Chinese adult-children completed the Chinese version of the PACQ. The structure of the questionnaire was analyzed using exploratory factor analysis (EFA and confirmatory factor analysis (CFA. We found that the Cronbach's α was 0.66–0.88 for fathers and 0.76–0.91 for mothers, which demonstrates high internal consistency reliabilities of the Chinese version of the PACQ. The Chinese version of the PACQ for father had similar constructs similar to with those of the original English version. However, a new factor for mothers, “attachment,” was derived from the original English version. The results suggested that the Chinese version of PACQ is a valid and reliable measure of relationship quality between Chinese adult-children and their parents.

In vitro surfactant structure-toxicity relationships: implications for surfactant use in sexually transmitted infection prophylaxis and contraception.

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Ângela S Inácio

Full Text Available BACKGROUND: The need for woman-controlled, cheap, safe, effective, easy-to-use and easy-to-store topical applications for prophylaxis against sexually transmitted infections (STIs makes surfactant-containing formulations an interesting option that requires a more fundamental knowledge concerning surfactant toxicology and structure-activity relationships. METHODOLOGY/PRINCIPAL FINDINGS: We report in vitro effects of surfactant concentration, exposure time and structure on the viability of mammalian cell types typically encountered in the vagina, namely, fully polarized and confluent epithelial cells, confluent but non-polarized epithelial-like cells, dendritic cells, and human sperm. Representatives of the different families of commercially available surfactants--nonionic (Triton X-100 and monolaurin, zwitterionic (DDPS, anionic (SDS, and cationic (C(nTAB (n = 10 to 16, C(12PB, and C(12BZK--were examined. Triton X-100, monolaurin, DDPS and SDS were toxic to all cell types at concentrations around their critical micelle concentration (CMC suggesting a non-selective mode of action involving cell membrane destabilization and/or destruction. All cationic surfactants were toxic at concentrations far below their CMC and showed significant differences in their toxicity toward polarized as compared with non-polarized cells. Their toxicity was also dependent on the chemical nature of the polar head group. Our results suggest an intracellular locus of action for cationic surfactants and show that their structure-activity relationships could be profitably exploited for STI prophylaxis in vaginal gel formulations. The therapeutic indices comparing polarized epithelial cell toxicity to sperm toxicity for all surfactants examined, except C(12PB and C(12BZK, does not justify their use as contraceptive agents. C(12PB and C(12BZK are shown to have a narrow therapeutic index recommending caution in their use in contraceptive formulations. CONCLUSIONS/SIGNIFICANCE

Super-resolution structure of DNA significantly differs in buccal cells of controls and Alzheimer's patients.

Science.gov (United States)

Garcia, Angeles; Huang, David; Righolt, Amanda; Righolt, Christiaan; Kalaw, Maria Carmela; Mathur, Shubha; McAvoy, Elizabeth; Anderson, James; Luedke, Angela; Itorralba, Justine; Mai, Sabine

2017-09-01

The advent of super-resolution microscopy allowed for new insights into cellular and physiological processes of normal and diseased cells. In this study, we report for the first time on the super-resolved DNA structure of buccal cells from patients with Alzheimer's disease (AD) versus age- and gender-matched healthy, non-caregiver controls. In this super-resolution study cohort of 74 participants, buccal cells were collected and their spatial DNA organization in the nucleus examined by 3D Structured Illumination Microscopy (3D-SIM). Quantitation of the super-resolution DNA structure revealed that the nuclear super-resolution DNA structure of individuals with AD significantly differs from that of their controls (p structure of AD significantly differs in mild, moderate, and severe disease with respect to the DNA-containing and DNA-free/poor spaces. We conclude that whole genome remodeling is a feature of buccal cells in AD. © 2016 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.

Structure-function relationships in elderly resting-state-networks : influence of age and cognitive performance

OpenAIRE

Jockwitz, Christiane

2016-01-01

The aim of this work was to investigate the structure-function relationship in cognitive resting state networks in a large population-based elderly sample. The first study characterized the functional connectivity in four cognitive resting state networks with respect to age, gender and cognitive performance: Default Mode Network (DMN), executive, and left and right frontoparietal resting state networks. The second study assessed the structural correlates of the functional reorganization of th...

Sustainable Corporate Social Media Marketing Based on Message Structural Features: Firm Size Plays a Significant Role as a Moderator

OpenAIRE

Moon Young Kang; Byungho Park

2018-01-01

Social media has been receiving attention as a cost-effective tool to build corporate brand image and to enrich customer relationships. This phenomenon calls for more attention to developing a model that measures the impact of structural features, used in corporate social media messages. Based on communication science, this study proposes a model to measure the impact of three essential message structural features (interactivity, formality, and immediacy) in corporate social media on customer...

Comparative pharmacodynamic analysis of imidazoline compounds using rat model of ocular mydriasis with a test of quantitative structure-activity relationships.

Science.gov (United States)

Raczak-Gutknecht, Joanna; Nasal, Antoni; Frąckowiak, Teresa; Kornicka, Anita; Sączewski, Franciszek; Wawrzyniak, Renata; Kubik, Łukasz; Kaliszan, Roman

2017-09-10

Imidazol(in)e derivatives, having the chemical structure similar to clonidine, exert diverse pharmacological activities connected with their interactions with alpha2-adrenergic receptors, e.g. hypotension, bradycardia, sedation as well as antinociceptive, anxiolytic, antiarrhythmic, muscle relaxant and mydriatic effects. The mechanism of pupillary dilation observed after systemic administration of imidazol(in)es to rats, mice and cats depends on the stimulation of postsynaptic alpha2-adrenoceptors within the brain. It was proved that the central nervous system (CNS)-localized I1-imidazoline receptors are not engaged in those effects. It appeared interesting to analyze the CNS-mediated pharmacodynamics of imidazole(in)e agents in terms of their chromatographic and calculation chemistry-derived parameters. In the present study a systematic determination and comparative pharmacometric analysis of mydriatic effects in rats were performed on a series of 20 imidazol(in)e agents, composed of the well-known drugs and of the substances used in experimental pharmacology. The eye pupil dilatory activities of the compounds were assessed in anesthetized Wistar rats according to the established Koss method. Among twenty imidazol(in)e derivatives studied, 18 produced diverse dose-dependent mydriatic effects. In the quantitative structure-activity relationships (QSAR) analysis, the pharmacological data (half maximum mydriatic effect - ED 50 in μmol/kg) were considered along with the structural parameters of the agents from molecular modeling. The theoretically calculated lipophilicity parameters, CLOGP, of imidazol(in)es, as well as their lipophilicity parameters from HPLC, logk w , were also considered. The attempts to derive statistically significant QSAR equations for a full series of the agents under study were unsuccessful. However, for a subgroup of eight apparently structurally related imidazol(in)es a significant relationship between log(1/ED 50 ) and logk w values was

New Insights about Enzyme Evolution from Large Scale Studies of Sequence and Structure Relationships*

Science.gov (United States)

Brown, Shoshana D.; Babbitt, Patricia C.

2014-01-01

Understanding how enzymes have evolved offers clues about their structure-function relationships and mechanisms. Here, we describe evolution of functionally diverse enzyme superfamilies, each representing a large set of sequences that evolved from a common ancestor and that retain conserved features of their structures and active sites. Using several examples, we describe the different structural strategies nature has used to evolve new reaction and substrate specificities in each unique superfamily. The results provide insight about enzyme evolution that is not easily obtained from studies of one or only a few enzymes. PMID:25210038

Quantitative structure-retention relationship studies with immobilized artificial membrane chromatography II: partial least squares regression.

Science.gov (United States)

Li, Jie; Sun, Jin; He, Zhonggui

2007-01-26

We aimed to establish quantitative structure-retention relationship (QSRR) with immobilized artificial membrane (IAM) chromatography using easily understood and obtained physicochemical molecular descriptors and to elucidate which descriptors are critical to affect the interaction process between solutes and immobilized phospholipid membranes. The retention indices (logk(IAM)) of 55 structurally diverse drugs were determined on an immobilized artificial membrane column (IAM.PC.DD2) directly or obtained by extrapolation method for highly hydrophobic compounds. Ten simple physicochemical property descriptors (clogP, rings, rotatory bond, hydro-bond counting, etc.) of these drugs were collected and used to establish QSRR and predict the retention data by partial least squares regression (PLSR). Five descriptors, clogP, rotatory bond (RotB), rings, molecular weight (MW) and total surface area (TSA), were reserved by using the Variable Importance for Projection (VIP) values as criterion to build the final PLSR model. An external test set was employed to verify the QSRR based on the training set with the five variables, and QSRR by PLSR exhibited a satisfying predictive ability with R(p)=0.902 and RMSE(p)=0.400. Comparison of coefficients of centered and scaled variables by PLSR demonstrated that, for the descriptors studied, clogP and TSA have the most significant positive effect but the rotatable bond has significant negative effect on drug IAM chromatographic retention.

Structural Features of Sibling Dyads and Attitudes toward Sibling Relationships in Young Adulthood

Science.gov (United States)

Riggio, Heidi R.

2006-01-01

This study examined sibling-dyad structural variables (sex composition, age difference, current coresidence, position adjacency, family size, respondent and/or sibling ordinal position) and attitudes toward adult sibling relationships. A sample of 1,053 young adults (M age = 22.1 years) described one sibling using the Lifespan Sibling Relationship…

Molecular Descriptors Family on Structure Activity Relationships 3. Antituberculotic Activity of some Polyhydroxyxanthones

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Sorana BOLBOACĂ

2005-06-01

Full Text Available The antituberculotic activity of some polyhydroxyxanthones was estimated using the Molecular Descriptors Family on Structure Activity Relationships methodology. From a total number of 298110 real and distinct calculated descriptors, 94843 were significantly different and entered into multiple linear regression analysis. The best performing bi-varied model was obtained by use of all polyhydroxyxanthones. The MDF SAR model was validated splitting the molecules into training and test sets. A correlated correlations analysis was applied in other to compare the MDF SAR models with the previous SAR model. The prediction ability of antituberculotic activity of polyhydroxyxanthones with MDF SAR methodology is sustained by three arguments: leave-one-out procedure, training vs. test procedure, and the correlated correlations analysis. Looking at the bi-varied MDF SAR model, we can conclude that the antituberculotic activity of polyhydroxyxanthones is almost of geometrical nature (99% and is strongly dependent on partial atomic charge and group electronegativity.

Changing structure of income indoor air pollution relationship in India

International Nuclear Information System (INIS)

Kavi Kumar, K.S.; Viswanathan, Brinda

2007-01-01

Bio fuels are still a major source for cooking by many households in developing countries such as India causing significant disease burden due to indoor air pollution. While household income influences the choice of fuel the policies that affect accessibility and price of fuels also have an important role in determining the fuel choice. This study analyzes the pollution-income relationship for the period 1983-2000, separately across rural and urban households in India based on unit record data on fuel consumption obtained through National Sample Surveys. While a non-monotonic relationship is observed in rural India in both the decades, in urban India a similar relationship is observed only for the initial period indicating faster transition towards 'cleaner' fuels mainly enabled by policies that have been pro-urban. The study also finds that the impact of household size and composition on bio fuels is more negative than for clean fuels and is increasingly negative over time possibly due to greater awareness about the ill effects of such fuels

Structure-activity relationship of antiparasitic and cytotoxic indoloquinoline alkaloids, and their tricyclic and bicyclic analogues.

Science.gov (United States)

Van Baelen, Gitte; Hostyn, Steven; Dhooghe, Liene; Tapolcsányi, Pál; Mátyus, Péter; Lemière, Guy; Dommisse, Roger; Kaiser, Marcel; Brun, Reto; Cos, Paul; Maes, Louis; Hajós, György; Riedl, Zsuzsanna; Nagy, Ildikó; Maes, Bert U W; Pieters, Luc

2009-10-15

Based on the indoloquinoline alkaloids cryptolepine (1), neocryptolepine (2), isocryptolepine (3) and isoneocryptolepine (4), used as lead compounds for new antimalarial agents, a series of tricyclic and bicyclic analogues, including carbolines, azaindoles, pyrroloquinolines and pyrroloisoquinolines was synthesized and biologically evaluated. None of the bicyclic compounds was significantly active against the chloroquine-resistant strain Plasmodium falciparum K1, in contrast to the tricyclic derivatives. The tricyclic compound 2-methyl-2H-pyrido[3,4-b]indole (9), or 2-methyl-beta-carboline, showed the best in vitro activity, with an IC(50) value of 0.45 microM against P. falciparum K1, without apparent cytotoxicity against L6 cells (SI>1000). However, this compound was not active in the Plasmodium berghei mouse model. Structure-activity relationships are discussed and compared with related naturally occurring compounds.

New Insights into the Relationship Between Network Structure and Strain Induced Crystallization in Unvolcanized Natural Rubber by Synchrotron X-ray Diffraction

International Nuclear Information System (INIS)

Toki, S.; Hsiao, B.; Amnuaypornsri, S.; Sakdapipanich, J.

2009-01-01

The relationship between the network structure and strain-induced crystallization in un-vulcanized as well as vulcanized natural rubbers (NR) and synthetic poly-isoprene rubbers (IR) was investigated via synchrotron wide-angle X-ray diffraction (WAXD) technique. It was found that the presence of a naturally occurring network structure formed by natural components in un-vulcanized NR significantly facilitates strain-induced crystallization and enhances modulus and tensile strength. The stress-strain relation in vulcanized NR is due to the combined effect of chemical and naturally occurring networks. The weakness of naturally occurring network against stress and temperature suggests that vulcanized NR has additional relaxation mechanism due to naturally occurring network. The superior mechanical properties in NR compared with IR are mainly due to the existence of naturally occurring network structure.

Relationship between Online Learning Readiness and Structure and Interaction of Online Learning Students

Science.gov (United States)

Demir Kaymak, Zeliha; Horzum, Mehmet Baris

2013-01-01

Current study tried to determine whether a relationship exists between readiness levels of the online learning students for online learning and the perceived structure and interaction in online learning environments. In the study, cross sectional survey model was used. The study was conducted with 320 voluntary students studying online learning…

Fragment-based quantitative structure-activity relationship (FB-QSAR) for fragment-based drug design.

Science.gov (United States)

Du, Qi-Shi; Huang, Ri-Bo; Wei, Yu-Tuo; Pang, Zong-Wen; Du, Li-Qin; Chou, Kuo-Chen

2009-01-30

In cooperation with the fragment-based design a new drug design method, the so-called "fragment-based quantitative structure-activity relationship" (FB-QSAR) is proposed. The essence of the new method is that the molecular framework in a family of drug candidates are divided into several fragments according to their substitutes being investigated. The bioactivities of molecules are correlated with the physicochemical properties of the molecular fragments through two sets of coefficients in the linear free energy equations. One coefficient set is for the physicochemical properties and the other for the weight factors of the molecular fragments. Meanwhile, an iterative double least square (IDLS) technique is developed to solve the two sets of coefficients in a training data set alternately and iteratively. The IDLS technique is a feedback procedure with machine learning ability. The standard Two-dimensional quantitative structure-activity relationship (2D-QSAR) is a special case, in the FB-QSAR, when the whole molecule is treated as one entity. The FB-QSAR approach can remarkably enhance the predictive power and provide more structural insights into rational drug design. As an example, the FB-QSAR is applied to build a predictive model of neuraminidase inhibitors for drug development against H5N1 influenza virus. (c) 2008 Wiley Periodicals, Inc.

Sex differences in the relationship between white matter connectivity and creativity.

Science.gov (United States)

Ryman, Sephira G; van den Heuvel, Martijn P; Yeo, Ronald A; Caprihan, Arvind; Carrasco, Jessica; Vakhtin, Andrei A; Flores, Ranee A; Wertz, Christopher; Jung, Rex E

2014-11-01

Creative cognition emerges from a complex network of interacting brain regions. This study investigated the relationship between the structural organization of the human brain and aspects of creative cognition tapped by divergent thinking tasks. Diffusion weighted imaging (DWI) was used to obtain fiber tracts from 83 segmented cortical regions. This information was represented as a network and metrics of connectivity organization, including connectivity strength, clustering and communication efficiency were computed, and their relationship to individual levels of creativity was examined. Permutation testing identified significant sex differences in the relationship between global connectivity and creativity as measured by divergent thinking tests. Females demonstrated significant inverse relationships between global connectivity and creative cognition, whereas there were no significant relationships observed in males. Node specific analyses revealed inverse relationships across measures of connectivity, efficiency, clustering and creative cognition in widespread regions in females. Our findings suggest that females involve more regions of the brain in processing to produce novel ideas to solutions, perhaps at the expense of efficiency (greater path lengths). Males, in contrast, exhibited few, relatively weak positive relationships across these measures. Extending recent observations of sex differences in connectome structure, our findings of sexually dimorphic relationships suggest a unique topological organization of connectivity underlying the generation of novel ideas in males and females. Published by Elsevier Inc.

Cationic lipids: molecular structure/ transfection activity relationships and interactions with biomembranes.

Science.gov (United States)

Koynova, Rumiana; Tenchov, Boris

2010-01-01

Abstract Synthetic cationic lipids, which form complexes (lipoplexes) with polyanionic DNA, are presently the most widely used constituents of nonviral gene carriers. A large number of cationic amphiphiles have been synthesized and tested in transfection studies. However, due to the complexity of the transfection pathway, no general schemes have emerged for correlating the cationic lipid chemistry with their transfection efficacy and the approaches for optimizing their molecular structures are still largely empirical. Here we summarize data on the relationships between transfection activity and cationic lipid molecular structure and demonstrate that the transfection activity depends in a systematic way on the lipid hydrocarbon chain structure. A number of examples, including a large series of cationic phosphatidylcholine derivatives, show that optimum transfection is displayed by lipids with chain length of approximately 14 carbon atoms and that the transfection efficiency strongly increases with increase of chain unsaturation, specifically upon replacement of saturated with monounsaturated chains.

Refinement of the Fe4Al13 structure and its relationship to the quasihomological homeotypical structures

International Nuclear Information System (INIS)

Grin, J.; Burkhardt, U.; Ellner, M.; Peters, K.

1994-01-01

The crystal structure of Fe 4 Al 13 was refined using single crystal diffractometer data: pearson symbol mC102, space group C2/m; a=15.492(2) A, b=8.078(2) A, c=12.471(1) A, β=107.69(1) ; R F =0.053, R F (w)=0.044 for 1127 reflections and 137 refined parameters. The coordination numbers of atoms are 9, 10, 11 for iron and 10, 12, 13, 14 for aluminium. The shortest interatomic distances are: Fe-Fe - 2.902 A, Fe-Al - 2.374 A, Al-Al - 2.533 A. A preferred occupation of pentagonal prismatic coordinated positions by aluminium was found. The structural relationship between the Fe 4 Al 13 structure and chemically homologous and homeotypical structures of aluminium and gallium containing systems with the 3d transition metals is discussed. The greatest similarity was found concerning the coordination polyhedra, especially that of transition metal atoms. The main common feature of these homeotypical structures is the presence of pentagonal ''channels'', which is strongly dependent on the chemical composition. With increasing atomic number of the 3d transition metal, the stability range of these structures shifts to the transition metal-rich concentration. It is concluded that there is a connection between the occurrence of aluminium and gallium-containing decagonal and icosahedral phases and the existence of the infinite one-dimensional pentagonal channels in the intermetallic compounds showing a similar chemical composition. (orig.)

New insights about enzyme evolution from large scale studies of sequence and structure relationships.

Science.gov (United States)

Brown, Shoshana D; Babbitt, Patricia C

2014-10-31

Understanding how enzymes have evolved offers clues about their structure-function relationships and mechanisms. Here, we describe evolution of functionally diverse enzyme superfamilies, each representing a large set of sequences that evolved from a common ancestor and that retain conserved features of their structures and active sites. Using several examples, we describe the different structural strategies nature has used to evolve new reaction and substrate specificities in each unique superfamily. The results provide insight about enzyme evolution that is not easily obtained from studies of one or only a few enzymes. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

The nuclear higher-order structure defined by the set of topological relationships between DNA and the nuclear matrix is species-specific in hepatocytes.

Science.gov (United States)

Silva-Santiago, Evangelina; Pardo, Juan Pablo; Hernández-Muñoz, Rolando; Aranda-Anzaldo, Armando

2017-01-15

During the interphase the nuclear DNA of metazoan cells is organized in supercoiled loops anchored to constituents of a nuclear substructure or compartment known as the nuclear matrix. The stable interactions between DNA and the nuclear matrix (NM) correspond to a set of topological relationships that define a nuclear higher-order structure (NHOS). Current evidence suggests that the NHOS is cell-type-specific. Biophysical evidence and theoretical models suggest that thermodynamic and structural constraints drive the actualization of DNA-NM interactions. However, if the topological relationships between DNA and the NM were the subject of any biological constraint with functional significance then they must be adaptive and thus be positively selected by natural selection and they should be reasonably conserved, at least within closely related species. We carried out a coarse-grained, comparative evaluation of the DNA-NM topological relationships in primary hepatocytes from two closely related mammals: rat and mouse, by determining the relative position to the NM of a limited set of target sequences corresponding to highly-conserved genomic regions that also represent a sample of distinct chromosome territories within the interphase nucleus. Our results indicate that the pattern of topological relationships between DNA and the NM is not conserved between the hepatocytes of the two closely related species, suggesting that the NHOS, like the karyotype, is species-specific. Copyright © 2016 Elsevier B.V. All rights reserved.

The relationship between coherent structures and heat transfer processes in the initial region of a round jet

Energy Technology Data Exchange (ETDEWEB)

Drobniak, S.; Elsner, J.W. [Tech. Univ. of Czestochowa (Poland). Inst. of Thermal Machinary; El-Kassem, E.S.A. [Cairo University, Faculty of Engineering, Giza (Egypt)

1998-03-19

This paper describes an experimental study of the relationship between coherent vortical structures and the intensity of heat transport in the initial region of a round, free jet. Simultaneous measurements of velocity and temperature were taken with a four-wire combined probe in a jet that was acoustically stimulated with a frequency corresponding to the jet-column mode. The obtained results suggest that the mutual phase relations between oscillatory and random components of velocity and temperature lead to substantial intensification of the radial heat transport. Due to the same reason the longitudinal heat flux does not reveal a significant change in the presence of coherent structures and, as a result, a much wider spread of the temperature field in comparison with velocity may be observed as a characteristic feature of this flow. It was also observed that heat transfer processes are realized in substantial part by random turbulence generated due to the action of coherent motion. (orig.) With 13 figs., 27 refs.

Safety culture relationships with hospital nursing sensitive metrics.

Science.gov (United States)

Brown, Diane Storer; Wolosin, Robert

2013-01-01

Public demand for safer care has catapulted the healthcare industry's efforts to understand relationships between patient safety and hospital performance. This study explored linkages between staff perceptions of safety culture (SC) and ongoing measures of hospital nursing unit-based structures, care processes, and adverse patient outcomes. Relationships between nursing-sensitive measures of hospital performance and SC were explored at the unit-level from 9 California hospitals and 37 nursing units. SC perceptions were measured 6 months prior to collection of nursing metrics and relationships between the two sets of data were explored using correlational and regression analyses. Significant relationships were found with reported falls and process measures for fall prevention. Multiple associations were identified with SC and the structure of care delivery: skill mix, staff turnover, and workload intensity demonstrated significant relationships with SC, explaining 22-45% of the variance. SC was an important factor to understand in the quest to advance safe patient care. These findings have affordability and care quality implications for hospital leadership. When senior leaders prioritized a safety culture, patient outcomes may have improved with less staff turnover and more productivity. A business case could be made for investing in patient safety systems to provide reliably safe care. © 2013 National Association for Healthcare Quality.

The Binding of Four Licorice Flavonoids to Bovine Serum Albumin by Multi-Spectroscopic and Molecular Docking Methods: Structure-Affinity Relationship

Science.gov (United States)

Hou, J.; Liang, Q.; Shao, S.

2017-03-01

Flavanones are the main compound of licorice, and the C'-4 position substitution is a significant structural feature for their biological activity. The ability of three selected flavanones (liquiritigenin, liquiritin, and liquiritin apioside) bearing different substituents (hydroxyl groups, glucose, and glucose-apiose sugar moiety) at the C'-4 position and a chalcone ( isoliquiritigenin, an isomer of liquiritigenin) to bind bovine serum albumin (BSA) was studied by multispectroscopic and molecular docking methods under physiological conditions. The binding mechanism of fl avonoids to BSA can be explained by the formation of a flavonoids-BSA complex, and the binding affinity is the strongest for isoliquiritigenin, followed by liquiritin apioside, liquiritin, and liquiritigenin. The thermodynamic analysis and the molecular docking indicated that the interaction between flavonoids and BSA was dominated by the hydrophobic force and hydrogen bonds. The competitive experiments as well as the molecular docking results suggested the most possible binding site of licorice flavonoids on BSA at subdomain IIA. These results revealed that the basic skeleton structure and the substituents at the C'-4 position of flavanones significantly affect the structure-affinity relationships of the licorice flavonoid binding to BSA.

Quantitative structure-cytotoxicity relationship of phenylpropanoid amides.

Science.gov (United States)

Shimada, Chiyako; Uesawa, Yoshihiro; Ishihara, Mariko; Kagaya, Hajime; Kanamoto, Taisei; Terakubo, Shigemi; Nakashima, Hideki; Takao, Koichi; Saito, Takayuki; Sugita, Yoshiaki; Sakagami, Hiroshi

2014-07-01

A total of 12 phenylpropanoid amides were subjected to quantitative structure-activity relationship (QSAR) analysis, based on their cytotoxicity, tumor selectivity and anti-HIV activity, in order to investigate on their biological activities. Cytotoxicity against four human oral squamous cell carcinoma (OSCC) cell lines and three human oral normal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor selectivity was evaluated by the ratio of the mean CC50 (50% cytotoxic concentration) against normal oral cells to that against OSCC cell lines. Anti-HIV activity was evaluated by the ratio of CC50 to EC50 (50% cytoprotective concentration from HIV infection). Physicochemical, structural, and quantum-chemical parameters were calculated based on the conformations optimized by the LowModeMD method followed by density functional theory (DFT) method. Twelve phenylpropanoid amides showed moderate cytotoxicity against both normal and OSCC cell lines. N-Caffeoyl derivatives coupled with vanillylamine and tyramine exhibited relatively higher tumor selectivity. Cytotoxicity against normal cells was correlated with descriptors related to electrostatic interaction such as polar surface area and chemical hardness, whereas cytotoxicity against tumor cells correlated with free energy, surface area and ellipticity. The tumor-selective cytotoxicity correlated with molecular size (surface area) and electrostatic interaction (the maximum electrostatic potential). The molecular size, shape and ability for electrostatic interaction are useful parameters for estimating the tumor selectivity of phenylpropanoid amides. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Modifiers in rhodium catalysts for carbon monoxide hydrogenation: Structure-activity relationships

Energy Technology Data Exchange (ETDEWEB)

Bhore, N. A.

1989-05-01

This report is aimed at identifying interesting modified rhodium systems and elucidating structure-activity relationships in these systems with the overall goal of understanding the scientific issues in the catalytic conversion of syngas to oxygenates. Specific additives (sodium and molybdenum) are selected based on the scoping experiments. The effect of the additives on supported rhodium catalysts is then investigated. Throughout the investigation, experiments and analysis were performed on real systems instead of ideal systems. 374 refs., 82 figs., 57 tabs.

Combining region- and network-level brain-behavior relationships in a structural equation model.

Science.gov (United States)

Bolt, Taylor; Prince, Emily B; Nomi, Jason S; Messinger, Daniel; Llabre, Maria M; Uddin, Lucina Q

2018-01-15

Brain-behavior associations in fMRI studies are typically restricted to a single level of analysis: either a circumscribed brain region-of-interest (ROI) or a larger network of brain regions. However, this common practice may not always account for the interdependencies among ROIs of the same network or potentially unique information at the ROI-level, respectively. To account for both sources of information, we combined measurement and structural components of structural equation modeling (SEM) approaches to empirically derive networks from ROI activity, and to assess the association of both individual ROIs and their respective whole-brain activation networks with task performance using three large task-fMRI datasets and two separate brain parcellation schemes. The results for working memory and relational tasks revealed that well-known ROI-performance associations are either non-significant or reversed when accounting for the ROI's common association with its corresponding network, and that the network as a whole is instead robustly associated with task performance. The results for the arithmetic task revealed that in certain cases, an ROI can be robustly associated with task performance, even when accounting for its associated network. The SEM framework described in this study provides researchers additional flexibility in testing brain-behavior relationships, as well as a principled way to combine ROI- and network-levels of analysis. Copyright © 2017 Elsevier Inc. All rights reserved.

[Eyeball structure changes in high myopic patients and their significance for forensic assessment].

Science.gov (United States)

Liu, Yi-Chang; Xia, Wen-Tao; Zhou, Xing-Tao; Liu, Rui-Jue; Bian, Shi-Zhong; Ying, Chong-Liang; Zhu, Guang-You

2008-10-01

There are irreversible eyeball structural changes in high myopic patients. These changes include axial length, corneal radius, anterior chamber depth, fundus degeneration, macula thickness, etc. There is a close relationship between the damage degree of visual function and these changes. The incidence of complications, such as vitreous opacity, posterior vitreous detachment, cataract, glaucoma, posterior staphyloma and retina detachment, is also highly related to the myopia diopter. More and more researches have indicated that the myopia diopter and the level of visual function are affected by multiple factors. It is promising to detect all of these changes by different kinds of methods, and to assess visual function through these changes. By clarifying these changes, it is also useful to distinguish traumatic damage from disease to provide evidence for forensic assessment of eye injuries.

Organization structure as a moderator of the relationship between procedural justice, interactional justice, perceived organizational support, and supervisory trust.

Science.gov (United States)

Ambrose, Maureen L; Schminke, Marshall

2003-04-01

Organizational justice researchers recognize the important role organization context plays in justice perceptions, yet few studies systematically examine contextual variables. This article examines how 1 aspect of context--organizational structure--affects the relationship between justice perceptions and 2 types of social exchange relationships, organizational and supervisory. The authors suggest that under different structural conditions, procedural and interactional justice will play differentially important roles in determining the quality of organizational social exchange (as evidenced by perceived organizational support [POS]) and supervisory social exchange (as evidenced by supervisory trust). In particular, the authors hypothesized that the relationship between procedural justice and POS would be stronger in mechanistic organizations and that the relationship between interactional justice and supervisory trust would be stronger in organic organizations. The authors' results support these hypotheses.

A Structural Equation Modeling of the Relationships between Depression, Drug Abuse and Social Support with Suicidal Ideation among Soldiers in Iran in 2015.

Science.gov (United States)

Nosratabadi, Mehdi; Halvaiepour, Zohreh

2016-01-01

Military service is a crucial period in the lives of young people and during this period soldier facing with multiple psychosocial problems. The present study aimed to explore structural analysis of the relationships between depression, drug abuse, social support and the risk of suicidal ideation among Military Medical University soldiers in Iran. In the present correlational research, a sample of 176 soldiers, from three units, was selected using randomly stratified sampling. Data were collected through the Social Support Questionnaire (SSQ), the Beck Depression Inventory-II (BDI-II), the Beck Scale for Suicide Ideation (BSS) and the Possibility of Drug Abuse Scale (LDAS). Structural equation modeling was used to test the fit of the model, identify direct and indirect effects of the psychosocial correlates. Data were analyzed using the SPSS and AMOS software (Verson22). out of the whole subjects, 28.4% had suicidal ideation and 65.3% had degrees of depression (mild to severe). A significant reverse relationship was observed between social support and suicidal ideation (pdrug abuse and suicidal ideation. The final structural model indicated that 74% of the variance in suicidal ideation was explained by the three examined variables of depression, social support and drug abuse. The overall results showed that the risk of suicidal ideation, depression and drug abuse are relatively significant in Military Medical University soldiers requiring taking serious actions by the authorities and other relevant organizations in order to improve the psychosocial health status of these soldiers.

Significance of Airborne Gamma-ray spectrometric data of Umm bisilla Area, central Eastern Desert, Egypt

Energy Technology Data Exchange (ETDEWEB)

Rabie, S I [Nuclear materials authority, Maadi, Cairo, (Egypt)

1995-10-01

Umm bisilla area, located in the Central Eastern Desert of Egypt, consists mainly of basement rocks. The present investigation of the airborne spectrometric data is to define the meaningful anomalies from the raw data by applying the significance factor techniques, by calculating the significant radioactive provinces. Determination of the gross structural pattern and broad variations in composition of the crystalline basement, to define the relationships between the tectonic features of the area as interpreted from aeromagnetic data, with the significant anomalies revealed from spectrometric data was carried out through the application of different magnetic techniques. Five significant uraniferous zones were detected associated with Umm Bisilla granite, amphibolite, and grey granite. The intersection of the structural lineaments interpreted from aeromagnetic data illustrated good correlation with the significant uranium anomalous zones interpreted from spectrometric data, and indicated that the concentration is structurally. 15 figs.

Dihydro-β-agarofuran sesquiterpenes from celastraceae species as anti-tumour-promoting agents: Structure-activity relationship.

Science.gov (United States)

Núñez, Marvin J; Jiménez, Ignacio A; Mendoza, Cristina R; Chavez-Sifontes, Marvin; Martinez, Morena L; Ichiishi, Eiichiro; Tokuda, Ryo; Tokuda, Harukuni; Bazzocchi, Isabel L

2016-03-23

Inhibition of tumour promotion in multistage chemical carcinogenesis is considered a promising strategy for cancer chemoprevention. In an ongoing investigation of bioactive secondary metabolites from Celastraceae species, five new dihydro-β-agarofuran sesquiterpenes (1-5), named Chiapens A-E, and seventeen known ones, were isolated from Maytenus chiapensis. Their structures were elucidated by extensive NMR spectroscopic and mass spectrometric techniques, and their absolute configurations were determined by circular dichroism studies, chemical correlations and biogenic means. The isolated compounds, along with twenty known sesquiterpenes, previously isolated from Zinowiewia costaricensis, have been tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorpol-13-acetate (TPA). Thirty three compounds from this series showed stronger effects than that of β-carotene, the reference inhibitor. The structure-activity relationship (SAR) analysis revealed that the type of substituent, in particular at the C-1 position of the sesquiterpene scaffold, was able to modulate the anti-tumour promoting activity. Compounds 3, 6, and 33 showed significant effects in an in vivo two-stage mouse-skin carcinogenesis model. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Research on the relationship between the structural properties of bedding layer in spring mattress and sleep quality.

Science.gov (United States)

Shen, Liming; Chen, Yu-xia; Guo, Yong; Zhong, ShiLu; Fang, Fei; Zhao, Jing; Hu, Tian-Yi

2012-01-01

Mattress, as a sleep platform, its types and physical properties has an important effect on sleep quality and rest efficiency. In this paper, by subjective evaluations, analysis of sleeping behaviors and tests of depth of sleep, the relationship between characteristics of the bedding materials, the structure of mattress, sleep quality and sleep behaviors were studied. The results showed that: (1) Characteristics of the bedding materials and structure of spring mattress had a remarkable effect on sleep behaviors and sleep quality. An optimum combination of the bedding materials, the structure of mattress and its core could improve the overall comfort of mattress, thereby improving the depth of sleep and sleep quality. (2) Sleep behaviors had a close relationship with sleeping postures and sleep habits. The characteristics of sleep behaviors vary from person to person.

Structure-activity relationships of heterogeneous catalysts from time-resolved X-ray absorption spectroscopy

International Nuclear Information System (INIS)

Ressler, T.; Jentoft, R.E.; Wienold, J.; Girgsdies, F.; Neisius, T.; Timpe, O.

2003-01-01

Knowing the composition and the evolution of the bulk structure of a heterogeneous catalyst under working conditions (in situ) is a pre-requisite for understanding structure-activity relationships. X-ray absorption spectroscopy can be employed to study a catalytically active material in situ. In addition to steady-state investigations, the technique permits experiments with a time-resolution in the sub-second range to elucidate the solid-state kinetics of the reactions involved. Combined with mass spectrometry, the evolution of the short-range order structure of a heterogeneous catalyst, the average valence of the constituent metals, and the phase composition can be obtained. Here we present results obtained from time-resolved studies on the reduction of MoO 3 in propene and in propene and oxygen

Quantitative structure-cytotoxicity relationship of piperic acid amides.

Science.gov (United States)

Shimada, Chiyako; Uesawa, Yoshihiro; Ishihara, Mariko; Kagaya, Hajime; Kanamoto, Taisei; Terakubo, Shigemi; Nakashima, Hideki; Takao, Koichi; Miyashiro, Takaki; Sugita, Yoshiaki; Sakagami, Hiroshi

2014-09-01

A total of 12 piperic acid amides, including piperine, were subjected to quantitative structure-activity relationship (QSAR) analysis, based on their cytotoxicity, tumor selectivity and anti-HIV activity, in order to find new biological activities. Cytotoxicity against four human oral squamous cell carcinoma (OSCC) cell lines and three human oral normal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor selectivity was evaluated by the ratio of the mean 50% cytotoxic concentration (CC50) against normal oral cells to that against OSCC cell lines. Anti-HIV activity was evaluated by the ratio of the CC50 to 50% HIV infection-cytoprotective concentration (EC50). Physicochemical, structural, and quantum-chemical parameters were calculated based on the conformations optimized by LowModeMD method followed by density functional theory method. All compounds showed low-to-moderate tumor selectivity, but no anti-HIV activity. N-Piperoyldopamine ( 8: ) which has a catechol moiety, showed the highest tumor selectivity, possibly due to its unique molecular shape and electrostatic interaction, especially its largest partial equalization of orbital electronegativities and vsurf descriptors. The present study suggests that molecular shape and ability for electrostatic interaction are useful parameters for estimating the tumor selectivity of piperic acid amides. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Structure/property relationships in polymer membranes for water purification and energy applications

Science.gov (United States)

Geise, Geoffrey

Providing sustainable supplies of purified water and energy is a critical global challenge for the future, and polymer membranes will play a key role in addressing these clear and pressing global needs for water and energy. Polymer membrane-based processes dominate the desalination market, and polymer membranes are crucial components in several rapidly developing power generation and storage applications that rely on membranes to control rates of water and/or ion transport. Much remains unknown about the influence of polymer structure on intrinsic water and ion transport properties, and these relationships must be developed to design next generation polymer membrane materials. For desalination applications, polymers with simultaneously high water permeability and low salt permeability are desirable in order to prepare selective membranes that can efficiently desalinate water, and a tradeoff relationship between water/salt selectivity and water permeability suggests that attempts to prepare such materials should rely on approaches that do more than simply vary polymer free volume. One strategy is to functionalize hydrocarbon polymers with fixed charge groups that can ionize upon exposure to water, and the presence of charged groups in the polymer influences transport properties. Additionally, in many emerging energy applications, charged polymers are exposed to ions that are very different from sodium and chloride. Specific ion effects have been observed in charged polymers, and these effects must be understood to prepare charged polymers that will enable emerging energy technologies. This presentation discusses research aimed at further understanding fundamental structure/property relationships that govern water and ion transport in charged polymer films considered for desalination and electric potential field-driven applications that can help address global needs for clean water and energy.

Evaluation of potential relationships between benthic community structure and toxic metals in Laizhou Bay.

Science.gov (United States)

Wu, Bin; Song, Jinming; Li, Xuegang

2014-10-15

The objective of the present study was to examine the relationships between benthic community structure and toxic metals using bivariate/multivariate techniques at 17 sediment locations in Laizhou Bay, North China. Sediment chemical data were evaluated against geochemical background values and sediment quality guidelines, which identified Cu and As as contaminants of concern with a moderate potential for adverse effects. Benthic community data were subjected to non-metric multidimensional scaling, which generated four groups of stations. Spearman rank correlation was then employed to explore the relationships between the major axes of heavy metals and benthic community structure. However, weak and insignificant correlations were found between these axes, indicating that contaminants of concern may not be the primary explanatory factors. Polychaeta were abundant in southern Laizhou Bay, serving as a warning regarding the health status of the ecosystem. Integrated sediment quality assessment showed sediments from northern central locations were impaired, displaying less diverse benthos and higher metal contamination. Copyright © 2014 Elsevier Ltd. All rights reserved.

Efficiently mapping structure-property relationships of gas adsorption in porous materials: application to Xe adsorption.

Science.gov (United States)

Kaija, A R; Wilmer, C E

2017-09-08

Designing better porous materials for gas storage or separations applications frequently leverages known structure-property relationships. Reliable structure-property relationships, however, only reveal themselves when adsorption data on many porous materials are aggregated and compared. Gathering enough data experimentally is prohibitively time consuming, and even approaches based on large-scale computer simulations face challenges. Brute force computational screening approaches that do not efficiently sample the space of porous materials may be ineffective when the number of possible materials is too large. Here we describe a general and efficient computational method for mapping structure-property spaces of porous materials that can be useful for adsorption related applications. We describe an algorithm that generates random porous "pseudomaterials", for which we calculate structural characteristics (e.g., surface area, pore size and void fraction) and also gas adsorption properties via molecular simulations. Here we chose to focus on void fraction and Xe adsorption at 1 bar, 5 bar, and 10 bar. The algorithm then identifies pseudomaterials with rare combinations of void fraction and Xe adsorption and mutates them to generate new pseudomaterials, thereby selectively adding data only to those parts of the structure-property map that are the least explored. Use of this method can help guide the design of new porous materials for gas storage and separations applications in the future.

First-Principles Study of Structure Property Relationships of Monolayer (Hydroxy)Oxide-Metal Bifunctional Electrocatalysts

DEFF Research Database (Denmark)

Zeng, Zhenhua; Kubal, Joseph; Greeley, Jeffrey Philip

2015-01-01

step towards accurate identification and prediction of a variety of oxide/electrode interfacial structure-properties relationships, but also provides the foundation for rational design and control of ‘targeted active phases’ at catalytic interfaces. The successful design of bifunctional......In the present study, on the basis of detailed density functional theory (DFT) calculations, and using Ni hydroxy(oxide) films on Pt(111) and Au(111) electrodes as model systems, we describe a detailed structural and electrocatalytic analysis of hydrogen evolution (HER) at three-phase boundaries...... under alkaline electrochemical conditions. We demonstrate that the structure and oxidation state of the films can be systematically tuned by changing the applied electrode potential and/or the nature of substrates. Structural features determined from the theoretical calculations provide a wealth...

Relationship between Professional Learning Community, Bureaucratic Structure and Organisational Trust in Primary Education Schools

Science.gov (United States)

Kalkan, Fatma

2016-01-01

This research uses relational survey method to determine the relationship between professional learning community, bureaucratic structure and organisational trust according to the perceptions of teachers who work in primary education schools. Data were collected from 805 teachers who work in primary education schools in the districts (Altindag,…

Computational models for structure-hydrophobicity relationships of 4-carboxyl-2,6-dinitrophenyl azo hydroxynaphthalenes.

Science.gov (United States)

Idowu, Olakunle S; Adegoke, Olajire A; Idowu, Abiola; Olaniyi, Ajibola A

2007-01-01

Some phenyl azo hydroxynaphthalene dyes (e.g., sunset yellow) are certified as approved colorants for food, cosmetics, and drug formulations. The hydrophobicity of 4 newly synthesized azo dyes of the phenyl azo hydroxynaphthalene class was investigated, as a training set, with the goal of developing models for quantitative structure-property relationships (QSPR). Retention behavior of the molecules reversed-phase thin-layer chromatography (RPTLC) was investigated using liquid paraffin-coated silica gel as the stationary phase. Mobile phases consisted of aqueous mixtures of methanol, acetone, and dimethylformamide (DMF). Basic hydrophobicity parameter (Rmw), specific hydrophobic surface area (S), and isocratic chromatographic hydrophobicity index (phio) were computed from the chromatographic data. The hydrophobicity index (Rm) decreased linearly with increasing concentration of organic modifiers. Extrapolated Rmw values obtained by using DMF and acetone differ significantly from the value obtained by using methanol as organic modifier [P dyes and may also play useful roles in computer-assisted molecular discovery of nontoxic azo dyes.

Computational modeling of the structure-function relationship in human placental terminal villi.

OpenAIRE

Plitman, Mayo R; Olsthoorn, Jason; Charnock-Jones, David Stephen; Burton, Graham James; Oyen, Michelle Lynn

2016-01-01

Placental oxygen transport takes place at the final branches of the villous tree and is dictated by the relative arrangement of the maternal and fetal circulations. Modeling techniques have failed to accurately assess the structure-function relationship in the terminal villi due to the geometrical complexity. Three-dimensional blood flow and oxygen transport was modeled in four terminal villi reconstructed from confocal image stacks. The blood flow was analyzed along the center lines of capil...

INTERDEPENDENCE BETWEEN RELATIONSHIP QUALITY DIMENSIONS

Directory of Open Access Journals (Sweden)

Mario Pepur

2011-02-01

Full Text Available Tourism-dependent economy, unfavourable structure of accommodation and hotel capacity, seasonality of business and liquidity problems indicate importance of the relationships between hotels and banks in Croatia. Since the capital investments in new and modern capacities are necessity, the quality of their relationship would determine the future of Croatian economy as a whole in the long run. Regarding the capital investments, it is crucially important that cooperation between the employees in both business entities is based on the satisfaction, trust and commitment. In this way, every potential uncertainty as a consequence of the entity’s actions could be minimized. In this paper, 356 tourist objects are hierarchically clustered according to the relationship quality dimensions for the purpose of testing the characteristics according to which the clusters significantly differentiate. Consequently, the interdependence between the observed relationship quality dimensions is examined.

Processing-structure-property relationships of carbon nanotube and nanoplatelet enabled piezoresistive sensors

Science.gov (United States)

Luo, Sida

Individual carbon nanotubes (CNTs) possess excellent piezoresistive performance, which is manifested by the significant electrical resistance change when subject to mechanical deformation. In comparison to individual CNTs, the CNT thin films, formed by a random assembly of individual tubes or bundles, show much lower piezoresistive sensitivity. Given the progress made to date in developing CNT ensemble based-piezoresistive sensors, the related piezoresistive mechanism(s) are still not well understood. The crucial step to obtain a better understanding of this issue is to study the effects of CNT structure in the dispersion on the piezoresistivity of CNT ensemble based-piezoresistive sensors. To reach this goal, my Ph.D. research first focuses on establishing the processing-structure-property relationship of SWCNT thin film piezoresistive sensors. The key accomplishment contains: 1) developing the combined preparative ultracentrifuge method (PUM) and dynamic light scattering (DLS) method to quantitatively characterized SWCNT particle size in dispersions under various sonication conditions; 2) designing combined ultrasonication and microfluidization processing protocol for high throughput and large-scale production of high quality SWCNT dispersions; 3) fabricating varied SWCNT thin film piezoresistive sensors through spray coating technique and immersion-drying post-treatment; and 4) investigating the effect of microstructures of SWCNTs on piezoresistivity of SWCNT thin film sensors. This experimental methodology for quantitative and systematic investigation of the processing-structure-property relationships provides a means for the performance optimization of CNT ensemble based piezoresistive sensors. As a start to understand the piezoresistive mechanism, the second focus of my Ph.D. research is studying charge transport behaviors in SWCNT thin films. It was found that the temperature-dependent sheet resistance of SWCNT thin films could be explained by a 3D variable

Structure-activity relationships of nucleoside analogues for inhibition of tick-borne encephalitis virus

Czech Academy of Sciences Publication Activity Database

Eyer, L.; Šmídková, Markéta; Nencka, Radim; Neča, J.; Kastl, T.; Palus, Martin; De Clercq, E.; Růžek, Daniel

2016-01-01

Roč. 133, Sep (2016), s. 119-129 ISSN 0166-3542 R&D Projects: GA MZd(CZ) NV16-34238A; GA ČR(CZ) GA16-20054S Institutional support: RVO:61388963 ; RVO:60077344 Keywords : structure-activity relationship * tick-borne encephalitis * nucleoside inhibitor * antiviral activity * cytotoxicity Subject RIV: CC - Organic Chemistry; EE - Microbiology, Virology (BC-A) Impact factor: 4.271, year: 2016

Representation of molecular structure using quantum topology with inductive logic programming in structure-activity relationships.

Science.gov (United States)

Buttingsrud, Bård; Ryeng, Einar; King, Ross D; Alsberg, Bjørn K

2006-06-01

The requirement of aligning each individual molecule in a data set severely limits the type of molecules which can be analysed with traditional structure activity relationship (SAR) methods. A method which solves this problem by using relations between objects is inductive logic programming (ILP). Another advantage of this methodology is its ability to include background knowledge as 1st-order logic. However, previous molecular ILP representations have not been effective in describing the electronic structure of molecules. We present a more unified and comprehensive representation based on Richard Bader's quantum topological atoms in molecules (AIM) theory where critical points in the electron density are connected through a network. AIM theory provides a wealth of chemical information about individual atoms and their bond connections enabling a more flexible and chemically relevant representation. To obtain even more relevant rules with higher coverage, we apply manual postprocessing and interpretation of ILP rules. We have tested the usefulness of the new representation in SAR modelling on classifying compounds of low/high mutagenicity and on a set of factor Xa inhibitors of high and low affinity.

Structurally-constrained relationships between cognitive states in the human brain.

Directory of Open Access Journals (Sweden)

Ann M Hermundstad

2014-05-01

Full Text Available The anatomical connectivity of the human brain supports diverse patterns of correlated neural activity that are thought to underlie cognitive function. In a manner sensitive to underlying structural brain architecture, we examine the extent to which such patterns of correlated activity systematically vary across cognitive states. Anatomical white matter connectivity is compared with functional correlations in neural activity measured via blood oxygen level dependent (BOLD signals. Functional connectivity is separately measured at rest, during an attention task, and during a memory task. We assess these structural and functional measures within previously-identified resting-state functional networks, denoted task-positive and task-negative networks, that have been independently shown to be strongly anticorrelated at rest but also involve regions of the brain that routinely increase and decrease in activity during task-driven processes. We find that the density of anatomical connections within and between task-positive and task-negative networks is differentially related to strong, task-dependent correlations in neural activity. The space mapped out by the observed structure-function relationships is used to define a quantitative measure of separation between resting, attention, and memory states. We find that the degree of separation between states is related to both general measures of behavioral performance and relative differences in task-specific measures of attention versus memory performance. These findings suggest that the observed separation between cognitive states reflects underlying organizational principles of human brain structure and function.

Methanol oxidation reaction on core-shell structured Ruthenium-Palladium nanoparticles: Relationship between structure and electrochemical behavior

Science.gov (United States)

Kübler, Markus; Jurzinsky, Tilman; Ziegenbalg, Dirk; Cremers, Carsten

2018-01-01

In this work the relationship between structural composition and electrochemical characteristics of Palladium(Pd)-Ruthenium(Ru) nanoparticles during alkaline methanol oxidation reaction is investigated. The comparative study of a standard alloyed and a precisely Ru-core-Pd-shell structured catalyst allows for a distinct investigation of the electronic effect and the bifunctional mechanism. Core-shell catalysts benefit from a strong electronic effect and an efficient Pd utilization. It is found that core-shell nanoparticles are highly active towards methanol oxidation reaction for potentials ≥0.6 V, whereas alloyed catalysts show higher current outputs in the lower potential range. However, differential electrochemical mass spectrometry (DEMS) experiments reveal that the methanol oxidation reaction on core-shell structured catalysts proceeds via the incomplete oxidation pathway yielding formaldehyde, formic acid or methyl formate. Contrary, the alloyed catalyst benefits from the Ru atoms at its surface. Those are found to be responsible for high methanol oxidation activity at lower potentials as well as for complete oxidation of CH3OH to CO2 via the bifunctional mechanism. Based on these findings a new Ru-core-Pd-shell-Ru-terrace catalyst was synthesized, which combines the advantages of the core-shell structure and the alloy. This novel catalyst shows high methanol electrooxidation activity as well as excellent selectivity for the complete oxidation pathway.

Atomic Scale Structure-Chemistry Relationships at Oxide Catalyst Surfaces and Interfaces

Science.gov (United States)

McBriarty, Martin E.

Oxide catalysts are integral to chemical production, fuel refining, and the removal of environmental pollutants. However, the atomic-scale phenomena which lead to the useful reactive properties of catalyst materials are not sufficiently understood. In this work, the tools of surface and interface science and electronic structure theory are applied to investigate the structure and chemical properties of catalytically active particles and ultrathin films supported on oxide single crystals. These studies focus on structure-property relationships in vanadium oxide, tungsten oxide, and mixed V-W oxides on the surfaces of alpha-Al2O3 and alpha-Fe2O 3 (0001)-oriented single crystal substrates, two materials with nearly identical crystal structures but drastically different chemical properties. In situ synchrotron X-ray standing wave (XSW) measurements are sensitive to changes in the atomic-scale geometry of single crystal model catalyst surfaces through chemical reaction cycles, while X-ray photoelectron spectroscopy (XPS) reveals corresponding chemical changes. Experimental results agree with theoretical calculations of surface structures, allowing for detailed electronic structure investigations and predictions of surface chemical phenomena. The surface configurations and oxidation states of V and W are found to depend on the coverage of each, and reversible structural shifts accompany chemical state changes through reduction-oxidation cycles. Substrate-dependent effects suggest how the choice of oxide support material may affect catalytic behavior. Additionally, the structure and chemistry of W deposited on alpha-Fe 2O3 nanopowders is studied using X-ray absorption fine structure (XAFS) measurements in an attempt to bridge single crystal surface studies with real catalysts. These investigations of catalytically active material surfaces can inform the rational design of new catalysts for more efficient and sustainable chemistry.

Multivariate quantitative structure-pharmacokinetic relationships (QSPKR) analysis of adenosine A(1) receptor agonists in rat

NARCIS (Netherlands)

Van der Graaf, PH; Nilsson, J; Van Schaick, EA; Danhof, M

The aim of this study was to investigate the feasibility of a quantitative structure-pharmacokinetic relationships (QSPKR) method based on contemporary three-dimensional (3D) molecular characterization and multivariate statistical analysis. For this purpose, the programs SYBYL/CoMFA, GRID, and

Relationships among Adolescents' Leisure Motivation, Leisure Involvement, and Leisure Satisfaction: A Structural Equation Model

Science.gov (United States)

Chen, Ying-Chieh; Li, Ren-Hau; Chen, Sheng-Hwang

2013-01-01

The purpose of this cross-sectional study was to test a cause-and-effect model of factors affecting leisure satisfaction among Taiwanese adolescents. A structural equation model was proposed in which the relationships among leisure motivation, leisure involvement, and leisure satisfaction were explored. The study collected data from 701 adolescent…

Structure-property relationship in cytotoxicity and cell uptake of poly(2-oxazoline) amphiphiles

KAUST Repository

Luxenhofer, Robert

2011-07-01

The family of poly(2-oxazoline)s (POx) is being increasingly investigated in the context of biomedical applications. We tested the relative cytotoxicity of POx and were able to confirm that these polymers are typically not cytotoxic even at high concentrations. Furthermore, we report structure-uptake relationships of a series of amphiphilic POx block copolymers that have different architectures, molar mass and chain termini. The rate of endocytosis can be fine-tuned over a broad range by changing the polymer structure. The cellular uptake increases with the hydrophobic character of the polymers and is observed even at nanomolar concentrations. Considering the structural versatility of this class of polymers, the relative ease of preparation and their stability underlines the potential of POx as a promising platform candidate for the preparation of next-generation polymer therapeutics.

The Relationships between Individualism, Nationalism, Ethnocentrism, and Authoritarianism in Flanders: A Continuous Time-Structural Equation Modeling Approach.

Science.gov (United States)

Angraini, Yenni; Toharudin, Toni; Folmer, Henk; Oud, Johan H L

2014-01-01

This article analyzes the relationships among nationalism (N), individualism (I), ethnocentrism (E), and authoritarianism (A) in continuous time (CT), estimated as a structural equation model. The analysis is based on the General Election Study for Flanders, Belgium, for 1991, 1995, and 1999. We find reciprocal effects between A and E and between E and I as well as a unidirectional effect from A on I. We furthermore find relatively small, but significant, effects from both I and E on N but no effect from A on N or from N on any of the other variables. Because of its central role in the N-I-E-A complex, mitigation of authoritarianism has the largest potential to reduce the spread of nationalism, ethnocentrism, and racism in Flanders.

PERCEPTIONS OF CLOSE AND GROUP RELATIONSHIPS MEDIATE THE RELATIONSHIP BETWEEN ANXIETY AND DEPRESSION OVER A DECADE LATER.

Science.gov (United States)

Jacobson, Nicholas C; Newman, Michelle G

2016-01-01

Previous research has demonstrated that anxiety reliably predicts later depression, but little has been uncovered about the mechanism underlying this connection. Interpersonal relationships appear to be a viable mechanism of the association as anxiety has been shown to predict later deficits in both close (e.g., "best friendships") and group relationships (e.g., classroom peer groups), and deficits in both close and group relationships have been linked to later depressive symptoms. The current study examined close and group relationships as potential mediators between anxiety and depression 12-14 years later. In a nationally representative sample of adolescents (N = 6,504), anxiety was measured at baseline, perceptions of close relationships (i.e., feeling loved) and perceptions of group relationships (i.e., feeling part of a group) were measured 6 months later, and depression levels and diagnosis were measured 12-14 years later. Using structural equation models, the results showed that adolescent perceptions of both close and group relationships significantly mediated the relationship between adolescent anxiety and adult levels of depression. Furthermore, perceptions of not being accepted/loved in close relationships significantly mediated the relationship between adolescent anxiety and clinical depression in adulthood. These results suggest that a perception of not being accepted in group relationships may be a mechanism by which heightened anxiety in adolescents leads to heightened nonclinical depression in adulthood. On the other hand, adolescent perceptions of not feeling loved or accepted in close relationships may be a mechanism by which heightened anxiety in adolescence leads to clinical depression--in adulthood. © 2015 Wiley Periodicals, Inc.

Relationships among structural empowerment, psychological empowerment, intent to stay and burnout in nursing field in mainland China-based on a cross-sectional questionnaire research.

Science.gov (United States)

Meng, Lina; Liu, Yanhui; Liu, Hongwei; Hu, Yu; Yang, Jipeng; Liu, Jingying

2015-06-01

The aim of the study was to explore the relationship among perceived structural empowerment, psychological empowerment, burnout and intent to stay by nurses in mainland China.With the shortage of nurses in many countries, including China, intent to stay is a dominant factor to influence the quality of care. Also, burnout is identified to negatively affect the quality of care. Empowered clinical nurse practical environment is related to intent to stay and burnout. In the current literature, there is a lack of data based on empowering environment discussing the relationship between burnout and intent to stay. The study used an anonymous questionnaire, filled voluntarily by 219 nurses from different sections in a city in mainland China, 2012.Structural equation modelling (SEM) was used to test the proposed hypotheses. Based on the SEM model, structural empowerment and psychological empowerment had significant positive effects on intent to stay of nurses and negative effects on burnout. Burnout had a significant negative effect on intent to stay. The final modified models yielded χ(2)  = 58.580, P > 0.05, χ(2) /df = 1.046, root mean square error of approximation = 0.015, Tucker-Lewis Index = 0.996, comparative fit index = 0.998,which indicated good fit indices. Creating a positive empowering workplace can encourage nurses to stay long and prevent burnout. Therefore, higher level of empowering environment is required. © 2014 Wiley Publishing Asia Pty Ltd.

Levels of Management Commitment: A Moderator the Structural Relationships among Critical Success Factors of TQM, World-Class Performance in Operations, and Company Financial Performance

Directory of Open Access Journals (Sweden)

Wakhid Slamet Ciptono

2012-01-01

Full Text Available This study investigates the moderating impacts of the three levels of management commitment (top, middle, and low levels on the structural relationships among the constructs— six critical success factors of TQM (quality improvement program, supervisory leadership, supplier involvement, management commitment, training to improve products/services, cross-functional relationships; world-class performance in operations (world-class company practices, operational excellence practices, company non-financial performance; and company financial performance. It uses a sample of 1,332 managers in 140 strategic business units (SBUs within 49 oil and gas companies in Indonesia. The empirical results indicate that the goodness-of-fit of the unconstrained model is much better than that of the constrained model, and this is an indicative that the three level of management moderates the structural relationships among the constructs. Those are, three levels of management act as a moderator variable between critical success factors of TQM, world-class company practices, operational excellence practices, company non-financial performance, and company financial performance. Results further reveal that world-class performances in operations (world-class company practices, operational excellence practices, and company non-financial performance were positively mediated the impact of critical success factors of TQM on company financial performance. Results also point out that five of six critical success factors of TQM positively associated with world-class company practices and operational excellence practices under the three levels of management (top, middle, low. World-class company practices and operational excellence practices have direct and significant effects on company non-financial performance (productivity, operational reliability. Furthermore, empirical results suggest that there is a positive and significant relationship between company non

Affective Structures among Students and Its Relationship with Academic Burnout with Emphasis on Gender

Science.gov (United States)

Bikar, Somaye; Marziyeh, Afsaneh; Pourghaz, Abdolwahab

2018-01-01

This study aimed to determine the relationship between affective structures and academic burnout among male and female third-grade high school students in Zahedan in the academic year 2016-2017. The current descriptive-correlational study had a sample including 362 students selected using a multistage cluster sampling method. To collect data,…

The Sport Commitment Model: An Investigation of Structural Relationships with Thai Youth Athlete Populations

Science.gov (United States)

Choosakul, Chairat; Vongjaturapat, Naruepon; Li, Fuzhong; Harmer, Peter

2009-01-01

Grounded in the conceptual framework of the Sport Commitment Model and previous empirical studies conducted in Western countries, this study was designed to (a) test and validate a Thai version of the Athlete Opinion Survey to assess components of the Sport Commitment Model in Thai youth athletes and (b) examine structural relationships among…

Physiological significance, structure and isolation of α-lactalbumin

Directory of Open Access Journals (Sweden)

Katarina Lisak Jakopović

2016-01-01

Full Text Available Along with the constant increase in the cheese milk production, the world whey production is increasing constantly too (>2 % per year. The excellent nutritional properties attributed to whey are mainly conditioned by the presence of highly valuable proteins with wide range of biological and functional properties. The main whey proteins are β-lactoglobulin (β-Lg and α-lactalbumin (α-La which are extensively used in functional foods and beverages, infant formulas, sport diets, but are a very good source of bioactive peptides too. Along with casein, β-Lg is most commonly made responsible for causing food allergies, especially in infants whose digestion system isn’t completely developed. Hence, there is a great interest for removing β-Lg prior to whey utilization in certain products. At the same time α-La was recognized as the nutritionally most valuable protein and might be regarded as an ideal ingredient for infant formulas. Thus, the aim of the present paper was to give an overview of the currently available methods for α-La isolation, and to highlight their advantages and disadvantages as well. Also, this paper reviews the most recent insights related to the structure and physiological significance of α-La.

THE MEDIATION ROLE OF RELATIONSIP QUALITY PERCEPTION ON THE RELATIONSHIP BETWEEN RELATIONSHIP MARKETING ACTIVITIES AND RE-PURCHASE INTENTION

Directory of Open Access Journals (Sweden)

Özer YILMAZ

2016-08-01

Full Text Available This study attempted to determine the effect of banks' relationship marketing operations on consumers' intentions of repurchasing and the mediator role of relational quality perception on this effect.  Data used in this study were gathered through a questionnaire from 482 participants in Balıkesir city centre. Descriptive statistics and structural equation modeling based on PLS algorithm (PLS-YEM were used for the analysis. Results indicated that banks' relationship marketing operations significantly and positively affected consumers' intentions of repurchasing and relational quality perceptions of consumers had a complete mediator effect on this relationship.

Intergroup Variation of Social Relationships in Wild Vervet Monkeys: A Dynamic Network Approach.

Science.gov (United States)

Borgeaud, Christèle; Sosa, Sebastian; Bshary, Redouan; Sueur, Cédric; van de Waal, Erica

2016-01-01

Social network analysis is a powerful tool that enables us to describe and quantify relationships between individuals. So far most of the studies rely on the analyses of various network snapshots, but do not capture changes over time. Here we use a stochastic actor-oriented model (SAOM) to test both the structure and the dynamics of relationships of three groups of wild vervet monkeys. We found that triadic closure (i.e., the friend of a friend is a friend) was significant in all three groups while degree popularity (i.e., the willingness to associate with individuals with high degree of connections) was significant in only two groups (AK, BD). The structure and dynamics of relationships according to the attributes of sex, matrilineand age differed significantly among groups. With respect to the structure, when analyzing the likelihood of bonds according to the different attributes, we found that individuals associate themselves preferably to individuals of the same sex only in two groups (AK, NH), while significant results for attachment to individuals of the same matriline were found also in two groups (BD, NH). With respect to the dynamics, i.e., how quickly relationships are modified, we found in two groups (AK, BD) that females' relationships were more prone to variation than males.' In the BD group, relationships within high-ranking matrilines were less stable than low-ranking ones while in the NH group, juveniles' relationships were also less stable than adults' ones. The intergroup variation indicates that establishing species-specific or even population specific characteristics of social networks for later between-species comparisons will be challenging. Although, such variation could also indicate some methodological issue, we are quite confident that data was collected similarly within the different groups. Our study therefore provides a potential new method to quantify social complexity according to natural demographic variation.

The synthesis, structure-toxicity relationship of cisplatin derivatives for the mechanism research of cisplatin-induced nephrotoxicity.

Science.gov (United States)

Hu, Jing; Wu, Tian-Ming; Li, Hong-Ze; Zuo, Ze-Ping; Zhao, Ying-Lan; Yang, Li

2017-08-01

Cisplatin is a widely used antineoplastic drug, while its nephrotoxicity limits the clinical application. Although several mechanisms contributing to nephrotoxicity have been reported, the direct protein targets are unclear. Herein we reported the synthesis of 29 cisplatin derivatives and the structure-toxicity relationship (STR) of these compounds with MTT assay in human renal proximal tubule cells (HK-2) and pig kidney epithelial cells (LLC-PK1). To the best of our knowledge, this study represented the first report regarding the structure-toxicity relationship (STR) of cisplatin derivatives. The potency of biotin-pyridine conjugated derivative 3 met the requirement for target identification, and the preliminary chemical proteomics results suggested that it is a promising tool for further target identification of cisplatin-induced nephrotoxicity. Copyright © 2017. Published by Elsevier Ltd.

Brand relationships: A study of five relationship constructs

DEFF Research Database (Denmark)

Bergkvist, Lars; Bech-Larsen, Tino

This study investigates the relationships between the five brand relationship constructs sense of community, brand identification, brand love, brand loyalty, and active engagement. Structural equation modelling with partial least squares showed provided support for six relational hypotheses...

Selective extraction of americium(III) over europium(III) ions with pyridylpyrazole ligands. Structure-property relationships

Energy Technology Data Exchange (ETDEWEB)

Su, Dongping; Liu, Ying; Li, Shimeng; Ding, Songdong; Jin, Yongdong; Wang, Zhipeng; Hu, Xiaoyang; Zhang, Lirong [Department of chemistry, Sichuan University, Chengdu (China)

2017-01-18

To clarify the structure-property relationships of pyridylpyrazole ligands and provide guidance for the design of new and more efficient ligands for the selective extraction of actinides over lanthanides, a series of alkyl-substituted pyridylpyrazole ligands with different branched chains at different positions of the pyrazole ring were synthesized. Extraction experiments showed that the pyridylpyrazole ligands exhibited good selective extraction abilities for Am{sup III} ions, and the steric effects of the branched chain had a significant impact on the distribution ratios of Am{sup III} and Eu{sup III} ions as well as the separation factor. Moreover, both slope analyses and UV/Vis spectrometry titrations indicated the formation of a 1:1 complex of 2-(1-octyl-1H-pyrazol-3-yl)pyridine (C8-PypzH) with Eu{sup III} ions. The stability constant (log K) for this complex obtained from the UV/Vis titration was 4.45 ± 0.04. Single crystals of the complexes of 3-(2-pyridyl)pyrazole (PypzH) with Eu(NO{sub 3}){sub 3} and Sm(NO{sub 3}){sub 3} were obtained; PypzH acts as a bidentate ligand in the crystal structures, and the N atom with a bound H atom did not participate in the coordination. In general, this study revealed some interesting findings on the effects of the alkyl-chain structure and the special complexation between pyridylpyrazole ligands and Ln{sup III} ions. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Structured social relationships: a review of volunteer home visiting programs for parents of young children.

Science.gov (United States)

Byrne, Fiona; Grace, Rebekah; Tredoux, Jaimie; Kemp, Lynn

2016-06-01

Objective The aims of the present paper were to: (1) review the research literature that contributes to an understanding of the role of volunteer home visiting programs in supporting the health and well being of families with young children; and (2) propose a conceptual model outlining service pathways for families in need of additional support. Methods An integrative literature review method was used, with a mix of electronic and manual search methods for the period January 1980-January 2014. Forty-five studies were identified that met the inclusion criteria for review and were coded according to themes developed a priori. Results There is little formal research that has examined the effectiveness of volunteer home visiting programs for supporting family health and well being. The available research suggests that volunteer home visiting programs provide socioemotional support through structured social relationships; however, there is limited empirical evidence to explicate the factors that contribute to these outcomes. Conclusion In recognition of the importance of peer support for new parents, the not-for-profit sector has been involved in providing volunteer home visiting services to families for decades. However, the body of research to support this work is characterised by methodological limitations, and rigorous evidence is limited. What is clear anecdotally and qualitatively from the existing research is that parents who are in need of additional support value engagement with a community volunteer. These structured social relationships appear to fulfil a service need within the community, helping build bridges to support social networks, and thus complementing professional services and relationships. Overall, structured social relationships in the form of volunteer home visiting programs appear to provide an important pathway to support family health and well being. Findings from the existing research are mixed and often characterised by methodological

Polyploidy and the relationship between leaf structure and function: implications for correlated evolution of anatomy, morphology, and physiology in Brassica.

Science.gov (United States)

Baker, Robert L; Yarkhunova, Yulia; Vidal, Katherine; Ewers, Brent E; Weinig, Cynthia

2017-01-05

Polyploidy is well studied from a genetic and genomic perspective, but the morphological, anatomical, and physiological consequences of polyploidy remain relatively uncharacterized. Whether these potential changes bear on functional integration or are idiosyncratic remains an open question. Repeated allotetraploid events and multiple genomic combinations as well as overlapping targets of artificial selection make the Brassica triangle an excellent system for exploring variation in the connection between plant structure (anatomy and morphology) and function (physiology). We examine phenotypic integration among structural aspects of leaves including external morphology and internal anatomy with leaf-level physiology among several species of Brassica. We compare diploid and allotetraploid species to ascertain patterns of phenotypic correlations among structural and functional traits and test the hypothesis that allotetraploidy results in trait disintegration allowing for transgressive phenotypes and additional evolutionary and crop improvement potential. Among six Brassica species, we found significant effects of species and ploidy level for morphological, anatomical and physiological traits. We identified three suites of intercorrelated traits in both diploid parents and allotetraploids: Morphological traits (such as leaf area and perimeter) anatomic traits (including ab- and ad- axial epidermis) and aspects of physiology. In general, there were more correlations between structural and functional traits for allotetraploid hybrids than diploid parents. Parents and hybrids did not have any significant structure-function correlations in common. Of particular note, there were no significant correlations between morphological structure and physiological function in the diploid parents. Increased phenotypic integration in the allotetraploid hybrids may be due, in part, to increased trait ranges or simply different structure-function relationships. Genomic and chromosomal

Quantitative structure activity relationship for the computational prediction of nitrocompounds carcinogenicity

International Nuclear Information System (INIS)

Morales, Aliuska Helguera; Perez, Miguel Angel Cabrera; Combes, Robert D.; Gonzalez, Maykel Perez

2006-01-01

Several nitrocompounds have been screened for carcinogenicity in rodents, but this is a lengthy and expensive process, taking two years and typically costing 2.5 million dollars, and uses large numbers of animals. There is, therefore, much impetus to develop suitable alternative methods. One possible way of predicting carcinogenicity is to use quantitative structure-activity relationships (QSARs). QSARs have been widely utilized for toxicity testing, thereby contributing to a reduction in the need for experimental animals. This paper describes the results of applying a TOPological substructural molecular design (TOPS-MODE) approach for predicting the rodent carcinogenicity of nitrocompounds. The model described 79.10% of the experimental variance, with a standard deviation of 0.424. The predictive power of the model was validated by leave-one-out validation, with a determination coefficient of 0.666. In addition, this approach enabled the contribution of different fragments to carcinogenic potency to be assessed, thereby making the relationships between structure and carcinogenicity to be transparent. It was found that the carcinogenic activity of the chemicals analysed was increased by the presence of a primary amine group bonded to the aromatic ring, a manner that was proportional to the ring aromaticity. The nitro group bonded to an aromatic carbon atom is a more important determinant of carcinogenicity than the nitro group bonded to an aliphatic carbon. Finally, the TOPS-MODE approach was compared with four other predictive models, but none of these could explain more than 66% of the variance in the carcinogenic potency with the same number of variables

Structure-Activity Relationships of the Human Immunodeficiency Virus Type 1 Maturation Inhibitor PF-46396.

Science.gov (United States)

Murgatroyd, Christopher; Pirrie, Lisa; Tran, Fanny; Smith, Terry K; Westwood, Nicholas J; Adamson, Catherine S

2016-09-15

HIV-1 maturation inhibitors are a novel class of antiretroviral compounds that consist of two structurally distinct chemical classes: betulinic acid derivatives and the pyridone-based compound PF-46396. It is currently believed that both classes act by similar modes of action to generate aberrant noninfectious particles via inhibition of CA-SP1 cleavage during Gag proteolytic processing. In this study, we utilized a series of novel analogues with decreasing similarity to PF-46396 to determine the chemical groups within PF-46396 that contribute to antiviral activity, Gag binding, and the relationship between these essential properties. A spectrum of antiviral activity (active, intermediate, and inactive) was observed across the analogue series with respect to CA-SP1 cleavage and HIV-1 (NL4-3) replication kinetics in Jurkat T cells. We demonstrate that selected inactive analogues are incorporated into wild-type (WT) immature particles and that one inactive analogue is capable of interfering with PF-46396 inhibition of CA-SP1 cleavage. Mutations that confer PF-46396 resistance can impose a defective phenotype on HIV-1 that can be rescued in a compound-dependent manner. Some inactive analogues retained the capacity to rescue PF-46396-dependent mutants (SP1-A3V, SP1-A3T, and CA-P157S), implying that they can also interact with mutant Gag. The structure-activity relationships observed in this study demonstrate that (i) the tert-butyl group is essential for antiviral activity but is not an absolute requirement for Gag binding, (ii) the trifluoromethyl group is optimal but not essential for antiviral activity, and (iii) the 2-aminoindan group is important for antiviral activity and Gag binding but is not essential, as its replacement is tolerated. Combinations of antiretroviral drugs successfully treat HIV/AIDS patients; however, drug resistance problems make the development of new mechanistic drug classes an ongoing priority. HIV-1 maturation inhibitors are novel as they

Structural optimization and structure-functional selectivity relationship studies of G protein-biased EP2 receptor agonists.

Science.gov (United States)

Ogawa, Seiji; Watanabe, Toshihide; Moriyuki, Kazumi; Goto, Yoshikazu; Yamane, Shinsaku; Watanabe, Akio; Tsuboi, Kazuma; Kinoshita, Atsushi; Okada, Takuya; Takeda, Hiroyuki; Tani, Kousuke; Maruyama, Toru

2016-05-15

The modification of the novel G protein-biased EP2 agonist 1 has been investigated to improve its G protein activity and develop a better understanding of its structure-functional selectivity relationship (SFSR). The optimization of the substituents on the phenyl ring of 1, followed by the inversion of the hydroxyl group on the cyclopentane moiety led to compound 9, which showed a 100-fold increase in its G protein activity compared with 1 without any increase in β-arrestin recruitment. Furthermore, SFSR studies revealed that the combination of meta and para substituents on the phenyl moiety was crucial to the functional selectivity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Composition - structure - properties relationships of peraluminous glasses for nuclear waste containment

International Nuclear Information System (INIS)

Piovesan, Victor

2016-01-01

Part of the Research and Development program concerning high level nuclear waste conditioning aims to assess new glass formulations able to incorporate a high waste content with enhanced properties in terms of homogeneity, thermal stability, long term behavior and process ability. This study focuses on peraluminous glasses, defined by an excess of aluminum ions Al"3"+ in comparison with modifier elements such as Na"+, Li"+ or Ca"2"+. A Design of Experiment approach has been employed to determine relationships between composition of simplified peraluminous glasses (SiO_2 - B_2O_3 - Al_2O_3 - Na_2O - Li_2O - CaO - La_2O_3) and their physical properties such as viscosity, glass transition temperature and glass homogeneity. Moreover, some structural investigation (NMR) was performed in order to better understand the structural role of Na"+, Li"+ and Ca"2"+ and the structural organization of peraluminous glasses. Then, physical and chemical properties of fully simulated peraluminous glasses were characterized to evaluate transposition between simplified and fully simulated glasses and also to put forward the potential of peraluminous glasses for nuclear waste containment. (author) [fr

The relationship between dental implant stability and trabecular bone structure using cone-beam computed tomography

Science.gov (United States)

2016-01-01

Purpose The objective of this study was to investigate the relationships between primary implant stability as measured by impact response frequency and the structural parameters of trabecular bone using cone-beam computed tomography(CBCT), excluding the effect of cortical bone thickness. Methods We measured the impact response of a dental implant placed into swine bone specimens composed of only trabecular bone without the cortical bone layer using an inductive sensor. The peak frequency of the impact response spectrum was determined as an implant stability criterion (SPF). The 3D microstructural parameters were calculated from CT images of the bone specimens obtained using both micro-CT and CBCT. Results SPF had significant positive correlations with trabecular bone structural parameters (BV/TV, BV, BS, BSD, Tb.Th, Tb.N, FD, and BS/BV) (Pmicro-CT and CBCT (Pimplant stability prediction by combining BV/TV and SMI in the stepwise forward regression analysis. Bone with high volume density and low surface density shows high implant stability. Well-connected thick bone with small marrow spaces also shows high implant stability. The combination of bone density and architectural parameters measured using CBCT can predict the implant stability more accurately than the density alone in clinical diagnoses. PMID:27127692

From Green to Blue: Site-Directed Mutagenesis of the Green Fluorescent Protein to Teach Protein Structure-Function Relationships

Science.gov (United States)

Giron, Maria D.; Salto, Rafael

2011-01-01

Structure-function relationship studies in proteins are essential in modern Cell Biology. Laboratory exercises that allow students to familiarize themselves with basic mutagenesis techniques are essential in all Genetic Engineering courses to teach the relevance of protein structure. We have implemented a laboratory course based on the…

Study of the structure-activity relationships of parabens: a practical class

Energy Technology Data Exchange (ETDEWEB)

Fernandes, Joao Paulo dos Santos; Savino, Giovanna; Amarante, Andre Cortinas Goncalves, E-mail: joao.fernandes@mackenzie.br [Centro de Ciencias Biologicas e da Saude, Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil); Sousa, Milena Rodrigues de; Silva, Geane Ramos da [Universidade Camilo Castelo Branco, Sao Paulo, SP (Brazil); Cianciulli, Maria Eliza [Universidade do Grande ABC, Santo Andre, SP (Brazil); Correa, Michelle Fidelis; Ferrarini, Marcio [Centro Universitario Sao Camilo, Sao Paulo, SP (Brazil)

2013-09-01

Parabens are p-hydroxybenzoic acid esters widely used as preservatives. With the aim of teaching the structure-activity relationships (SAR) knowledge in a practical form, this paper proposed a practical class to view the SAR of parabens as antimicrobial agents. Methyl, ethyl, n-propyl, isopropyl and isopentyl paraben compounds were synthesized and their respective antimicrobial activities were assessed through determination of minimum inhibitory concentrations (MIC) against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 stains. With the MIC values, it was possible to verify their correlation with calculated lipophilicity (ClogP). This method can be applied in practical Medicinal Chemistry classes. (author)

Study of the structure-activity relationships of parabens: a practical class

International Nuclear Information System (INIS)

Fernandes, João Paulo dos Santos; Savino, Giovanna; Amarante, André Cortinas Gonçalves; Sousa, Milena Rodrigues de; Silva, Geane Ramos da; Cianciulli, Maria Eliza; Corrêa, Michelle Fidelis; Ferrarini, Márcio

2013-01-01

Parabens are p-hydroxybenzoic acid esters widely used as preservatives. With the aim of teaching the structure-activity relationships (SAR) knowledge in a practical form, this paper proposed a practical class to view the SAR of parabens as antimicrobial agents. Methyl, ethyl, n-propyl, isopropyl and isopentyl paraben compounds were synthesized and their respective antimicrobial activities were assessed through determination of minimum inhibitory concentrations (MIC) against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 stains. With the MIC values, it was possible to verify their correlation with calculated lipophilicity (ClogP). This method can be applied in practical Medicinal Chemistry classes. (author)

Surface-Based fMRI-Driven Diffusion Tractography in the Presence of Significant Brain Pathology: A Study Linking Structure and Function in Cerebral Palsy

Science.gov (United States)

Cunnington, Ross; Boyd, Roslyn N.; Rose, Stephen E.

2016-01-01

Diffusion MRI (dMRI) tractography analyses are difficult to perform in the presence of brain pathology. Automated methods that rely on cortical parcellation for structural connectivity studies often fail, while manually defining regions is extremely time consuming and can introduce human error. Both methods also make assumptions about structure-function relationships that may not hold after cortical reorganisation. Seeding tractography with functional-MRI (fMRI) activation is an emerging method that reduces these confounds, but inherent smoothing of fMRI signal may result in the inclusion of irrelevant pathways. This paper describes a novel fMRI-seeded dMRI-analysis pipeline based on surface-meshes that reduces these issues and utilises machine-learning to generate task specific white matter pathways, minimising the requirement for manually-drawn ROIs. We directly compared this new strategy to a standard voxelwise fMRI-dMRI approach, by investigating correlations between clinical scores and dMRI metrics of thalamocortical and corticomotor tracts in 31 children with unilateral cerebral palsy. The surface-based approach successfully processed more participants (87%) than the voxel-based approach (65%), and provided significantly more-coherent tractography. Significant correlations between dMRI metrics and five clinical scores of function were found for the more superior regions of these tracts. These significant correlations were stronger and more frequently found with the surface-based method (15/20 investigated were significant; R2 = 0.43–0.73) than the voxelwise analysis (2 sig. correlations; 0.38 & 0.49). More restricted fMRI signal, better-constrained tractography, and the novel track-classification method all appeared to contribute toward these differences. PMID:27487011

Spatio-Temporal Story Mapping Animation Based On Structured Causal Relationships Of Historical Events

Science.gov (United States)

Inoue, Y.; Tsuruoka, K.; Arikawa, M.

2014-04-01

In this paper, we proposed a user interface that displays visual animations on geographic maps and timelines for depicting historical stories by representing causal relationships among events for time series. We have been developing an experimental software system for the spatial-temporal visualization of historical stories for tablet computers. Our proposed system makes people effectively learn historical stories using visual animations based on hierarchical structures of different scale timelines and maps.

Parent-Child Relations and Peer Associations as Mediators of the Family Structure--Substance Use Relationship

Science.gov (United States)

Crawford, Lizabeth A.; Novak, Katherine B.

2008-01-01

Using data from the National Education Longitudinal Survey of 1988, the authors assess the extent to which adolescents' levels of parental attachment and opportunities for participating in delinquent activities mediate the family structure--substance use relationship. A series of hierarchical regressions supported the hypotheses that high levels…

The Relationship between Racial Identity and Perceived Significance of the Election of President Barack Obama among African American Mothers.

Science.gov (United States)

Franco, Marisa; Smith-Bynum, Mia

2016-01-01

African American women's racial identity is a major determinant for how they interpret the world around them, yet there is little research examining how specific aspects of racial identity are linked with attitudes about an event that has been highly significant for African-Americans: the election of President Barack Obama. The current study examined the relationship between African American mothers' racial identity and their perceived significance of the election of President Barack Obama as an indicator of reduced systemic and actual racism for African Americans, using a sample of 110 African American mothers residing in a Northeastern metropolitan area. Results revealed that racial centrality and assimilation positively predicted perceived significance of President Obama's election for diminishing racism. Implications and future directions are discussed.

External validation of structure-biodegradation relationship (SBR) models for predicting the biodegradability of xenobiotics.

Science.gov (United States)

Devillers, J; Pandard, P; Richard, B

2013-01-01

Biodegradation is an important mechanism for eliminating xenobiotics by biotransforming them into simple organic and inorganic products. Faced with the ever growing number of chemicals available on the market, structure-biodegradation relationship (SBR) and quantitative structure-biodegradation relationship (QSBR) models are increasingly used as surrogates of the biodegradation tests. Such models have great potential for a quick and cheap estimation of the biodegradation potential of chemicals. The Estimation Programs Interface (EPI) Suite™ includes different models for predicting the potential aerobic biodegradability of organic substances. They are based on different endpoints, methodologies and/or statistical approaches. Among them, Biowin 5 and 6 appeared the most robust, being derived from the largest biodegradation database with results obtained only from the Ministry of International Trade and Industry (MITI) test. The aim of this study was to assess the predictive performances of these two models from a set of 356 chemicals extracted from notification dossiers including compatible biodegradation data. Another set of molecules with no more than four carbon atoms and substituted by various heteroatoms and/or functional groups was also embodied in the validation exercise. Comparisons were made with the predictions obtained with START (Structural Alerts for Reactivity in Toxtree). Biowin 5 and Biowin 6 gave satisfactorily prediction results except for the prediction of readily degradable chemicals. A consensus model built with Biowin 1 allowed the diminution of this tendency.

STRUCTURE-ACTIVITY RELATIONSHIP STUDY OF DITERPENES FOR TREATMENT OF ALZHEIMER'S DISEASE

Directory of Open Access Journals (Sweden)

Gabriel F. dos Santos

Full Text Available Alzheimer's disease is an irreversible, degenerative and age-related disease which is growing more and more with the increase in life expectancy. Kaurane diterpenes are a class of natural products available in large amounts in nature and isolated from plants grown worldwide. In the present work¸ twenty-seven kaurane diterpenes of natural origin and some readily available derivatives were assayed for acetylcholinesterase inhibition and the structure-activity relationship was analyzed. The kaurenoic acid derivatives screened showed to be promising inhibitors of AChE, which could provide new leads for drugs to fight Alzheimer's disease symptoms. Among them, eleven compounds showed activities comparable or higher than the positive control galantamine. Existence of an allylic hydroxyl group showed to be an important structural feature for AChE inhibition. In addition, presence of free hydroxyl groups at C-17 and C-19, furnished a diol especially active, able to completely inhibit AChE.

Structural relationships among attachment insecurity, alexithymia, and body esteem in women with eating disorders.

Science.gov (United States)

Keating, Leah; Tasca, Giorgio A; Hill, Robert

2013-08-01

Patients with eating disorders tend to experience low levels of body esteem. To assess the psychosocial processes that may predict low body esteem in these individuals, we assessed the structural interrelations among attachment anxiety, attachment avoidance, alexithymia, and body esteem in a cross-sectional sample of patients with eating disorders. We tested a model in which alexithymia mediates the relationship between attachment insecurity and body esteem. Participants were 300 women with anorexia nervosa (n = 109), bulimia nervosa (n = 130), and eating disorders not otherwise specified (n = 61) who completed pretreatment self-report questionnaires at intake for a day hospital treatment program. We found a direct and negative relationship between attachment anxiety and body esteem. Additionally, attachment avoidance had an indirect negative relationship to body esteem through alexithymia. These results indicate that therapists may attend to attachment insecurity and affective regulation strategies when addressing body image issues in patients with eating disorders. © 2013 Elsevier Ltd. All rights reserved.

The global relationship between chromatin physical topology, fractal structure, and gene expression

DEFF Research Database (Denmark)

Almassalha, Luay M; Tiwari, A; Ruhoff, P T

2017-01-01

in an empty space, but in a highly complex, interrelated, and dense nanoenvironment that profoundly influences chemical interactions. We explored the relationship between the physical nanoenvironment of chromatin and gene transcription in vitro. We analytically show that changes in the fractal dimension, D...... show that the increased heterogeneity of physical structure of chromatin due to increase in fractal dimension correlates with increased heterogeneity of gene networks. These findings indicate that the higher order folding of chromatin topology may act as a molecular-pathway independent code regulating...

Perceived Social Relationships and Science Learning Outcomes for Taiwanese Eighth Graders: Structural Equation Modeling with a Complex Sampling Consideration

Science.gov (United States)

Jen, Tsung-Hau; Lee, Che-Di; Chien, Chin-Lung; Hsu, Ying-Shao; Chen, Kuan-Ming

2013-01-01

Based on the Trends in International Mathematics and Science Study 2007 study and a follow-up national survey, data for 3,901 Taiwanese grade 8 students were analyzed using structural equation modeling to confirm a social-relation-based affection-driven model (SRAM). SRAM hypothesized relationships among students' perceived social relationships in…

The relationship between structural and functional connectivity: graph theoretical analysis of an EEG neural mass model

NARCIS (Netherlands)

Ponten, S.C.; Daffertshofer, A.; Hillebrand, A.; Stam, C.J.

2010-01-01

We investigated the relationship between structural network properties and both synchronization strength and functional characteristics in a combined neural mass and graph theoretical model of the electroencephalogram (EEG). Thirty-two neural mass models (NMMs), each representing the lump activity

Structure-property relationships of multiferroic materials: A nano perspective

Science.gov (United States)

Bai, Feiming

The integration of sensors, actuators, and control systems is an ongoing process in a wide range of applications covering automotive, medical, military, and consumer electronic markets. Four major families of ceramic and metallic actuators are under development: piezoelectrics, electrostrictors, magnetostrictors, and shape-memory alloys. All of these materials undergo at least two phase transformations with coupled thermodynamic order parameters. These transformations lead to complex domain wall behaviors, which are driven by electric fields (ferroelectrics), magnetic fields (ferromagnetics), or mechanical stress (ferroelastics) as they transform from nonferroic to ferroic states, contributing to the sensing and actuating capabilities. This research focuses on two multiferroic crystals, Pb(Mg1/3Nb 2/3)O3-PbTiO3 and Fe-Ga, which are characterized by the co-existence and coupling of ferroelectric polarization and ferroelastic strain, or ferro-magnetization and ferroelastic strain. These materials break the conventional boundary between piezoelectric and electrostrictors, or magnetostrictors and shape-memory alloys. Upon applying field or in a poled condition, they yield not only a large strain but also a large strain over field ratio, which is desired and much benefits for advanced actuator and sensor applications. In this thesis, particular attention has been given to understand the structure-property relationships of these two types of materials from atomic to the nano/macro scale. X-ray and neutron diffraction were used to obtain the lattice structure and phase transformation characteristics. Piezoresponse and magnetic force microscopy were performed to establish the dependence of domain configurations on composition, thermal history and applied fields. It has been found that polar nano regions (PNRs) make significant contributions to the enhanced electromechanical properties of PMN-x%PT crystals via assisting intermediate phase transformation. With increasing PT

Dictionary Pruning with Visual Word Significance for Medical Image Retrieval.

Science.gov (United States)

Zhang, Fan; Song, Yang; Cai, Weidong; Hauptmann, Alexander G; Liu, Sidong; Pujol, Sonia; Kikinis, Ron; Fulham, Michael J; Feng, David Dagan; Chen, Mei

2016-02-12

Content-based medical image retrieval (CBMIR) is an active research area for disease diagnosis and treatment but it can be problematic given the small visual variations between anatomical structures. We propose a retrieval method based on a bag-of-visual-words (BoVW) to identify discriminative characteristics between different medical images with Pruned Dictionary based on Latent Semantic Topic description. We refer to this as the PD-LST retrieval. Our method has two main components. First, we calculate a topic-word significance value for each visual word given a certain latent topic to evaluate how the word is connected to this latent topic. The latent topics are learnt, based on the relationship between the images and words, and are employed to bridge the gap between low-level visual features and high-level semantics. These latent topics describe the images and words semantically and can thus facilitate more meaningful comparisons between the words. Second, we compute an overall-word significance value to evaluate the significance of a visual word within the entire dictionary. We designed an iterative ranking method to measure overall-word significance by considering the relationship between all latent topics and words. The words with higher values are considered meaningful with more significant discriminative power in differentiating medical images. We evaluated our method on two public medical imaging datasets and it showed improved retrieval accuracy and efficiency.

An analysis of structural relationship among achievement motive on social participation, purpose in life, and role expectations among community dwelling elderly attending day services

Directory of Open Access Journals (Sweden)

Nobuyuki Sano

2016-01-01

Full Text Available Background. Achievement motive is defined as the intention to achieve one’s goals. Achievement motive is assumed to promote clients to choices and actions toward their valuable goal, so it is an important consideration in rehabilitation. Purpose. The purpose of this study is to demonstrate the structural relationship among achievement motive on purpose in life, social participation, and role expectation of community-dwelling elderly people. Methods. Participants were community-dwelling elderly people in day-service centers. A total of 281 participants (male: 127, female: 154 answered the self-administered questionnaire in cross-sectional research. The questionnaire was comprised of demographic data and scales that evaluated achievement motive, social participation, purpose in life, and role expectation. We studied the structural relationship established by our hypothesized model via a structural equation modeling approach. Results. We checked the standardized path coefficients and the modification indices; the modified model’s statistics were a good fit: CFI = 0.984, TLI = 0.983, RMSEA = 0.050, 90% CI [0.044–0.055]. Achievement motive had a significantly direct effect on purpose in life (direct effect = 0.445, p value < 0.001, a significantly indirect effect on purpose in life via social participation or role expectation (indirect effect = 0.170, p value < 0.001 and a total effect on purpose in life (total effect = 0.615. Discussion. This result suggests that enhancing the intention to achieve one’s goals enables participants to feel a spirit of challenge with a purpose and a sense of fulfillment in their daily lives.

An analysis of structural relationship among achievement motive on social participation, purpose in life, and role expectations among community dwelling elderly attending day services.

Science.gov (United States)

Sano, Nobuyuki; Kyougoku, Makoto

2016-01-01

Background. Achievement motive is defined as the intention to achieve one's goals. Achievement motive is assumed to promote clients to choices and actions toward their valuable goal, so it is an important consideration in rehabilitation. Purpose. The purpose of this study is to demonstrate the structural relationship among achievement motive on purpose in life, social participation, and role expectation of community-dwelling elderly people. Methods. Participants were community-dwelling elderly people in day-service centers. A total of 281 participants (male: 127, female: 154) answered the self-administered questionnaire in cross-sectional research. The questionnaire was comprised of demographic data and scales that evaluated achievement motive, social participation, purpose in life, and role expectation. We studied the structural relationship established by our hypothesized model via a structural equation modeling approach. Results. We checked the standardized path coefficients and the modification indices; the modified model's statistics were a good fit: CFI = 0.984, TLI = 0.983, RMSEA = 0.050, 90% CI [0.044-0.055]. Achievement motive had a significantly direct effect on purpose in life (direct effect = 0.445, p value < 0.001), a significantly indirect effect on purpose in life via social participation or role expectation (indirect effect = 0.170, p value < 0.001) and a total effect on purpose in life (total effect = 0.615). Discussion. This result suggests that enhancing the intention to achieve one's goals enables participants to feel a spirit of challenge with a purpose and a sense of fulfillment in their daily lives.

Structure-function relationships in highly modified shoots of cactaceae.

Science.gov (United States)

Mauseth, James D

2006-11-01

Cacti are extremely diverse structurally and ecologically, and so modified as to be intimidating to many biologists. Yet all have the same organization as most dicots, none differs fundamentally from Arabidopsis or other model plants. This review explains cactus shoot structure, discusses relationships between structure, ecology, development and evolution, and indicates areas where research on cacti is necessary to test general theories of morphogenesis. Cactus leaves are diverse; all cacti have foliage leaves; many intermediate stages in evolutionary reduction of leaves are still present; floral shoots often have large, complex leaves whereas vegetative shoots have microscopic leaves. Spines are modified bud scales, some secrete sugar as extra-floral nectaries. Many cacti have juvenile/adult phases in which the flowering adult phase (a cephalium) differs greatly from the juvenile; in some, one side of a shoot becomes adult, all other sides continue to grow as the juvenile phase. Flowers are inverted: the exterior of a cactus 'flower' is a hollow vegetative shoot with internodes, nodes, leaves and spines, whereas floral organs occur inside, with petals physically above stamens. Many cacti have cortical bundles vascularizing the cortex, however broad it evolves to be, thus keeping surface tissues alive. Great width results in great weight of weak parenchymatous shoots, correlated with reduced branching. Reduced numbers of shoot apices is compensated by great increases in number of meristematic cells within individual SAMs. Ribs and tubercles allow shoots to swell without tearing during wet seasons. Shoot epidermis and cortex cells live and function for decades then convert to cork cambium. Many modifications permit water storage within cactus wood itself, adjacent to vessels.

Relationship and significance of serum leptin with blood insulin and lipid in 6-13 years old obese children

International Nuclear Information System (INIS)

Sheng Chunyong; Wang Chunlan; Zhang Linong

2005-01-01

To explore relationship and significance of Serum Leptin with BMI, Insulin, triglyceride (TG) and total cholesterol (TC) in obese children aged 6-13 years. Serum Leptin of school-age children 118 (64 male, 54 female; normal non-obese 56 and obese 62) were deter- mined and compared with BMI, Insulin, TG and TC. The results showed that: (1) Each index of obese children was remarkably higher than that of non-obese children (P 0.05). (3) Leptin was poritinely corelation with BMI, insulin, TG and TC(P=0.001). Leptin level in serum may varied according to sex, BMI or blood lipid level. It is of great significance in prevention and treatment of obesity to use drug which may improve Leptin receptor effect. (authors)

Some Relationships Between Psychological Structure, Educational Beliefs, and Teaching Strategies in Three Types of Teacher Trainees.

Science.gov (United States)

Nier, Charles J.

This study investigated systematic relationships among teacher personality types (Ambitious, Conscientious, and Indulgent), preservice educational beliefs, and intern classroom practices. The investigation traced the theoretical and empirical linkage from personality structure though educational ideology and finally to perceptions of teacher…

Performance evaluation recommendations of nuclear power plants outdoor significant civil structures earthquake resistance. Technical documentation

International Nuclear Information System (INIS)

2005-06-01

The Japan Society of Civil Engineers has updated performance evaluation recommendations of nuclear power plants outdoor significant civil structures earthquake resistance in June 2005. Experimental and analytical considerations on the seismic effects evaluation criteria, such as analytical seismic models of soils for underground structures, effects of vertical motions on time-history dynamic analysis and shear fracture of reinforced concretes by cyclic loadings, were shown in this document and incorporated in new recommendations. (T. Tanaka)

3-cyanoindole-based inhibitors of inosine monophosphate dehydrogenase: synthesis and initial structure-activity relationships.

Science.gov (United States)

Dhar, T G Murali; Shen, Zhongqi; Gu, Henry H; Chen, Ping; Norris, Derek; Watterson, Scott H; Ballentine, Shelley K; Fleener, Catherine A; Rouleau, Katherine A; Barrish, Joel C; Townsend, Robert; Hollenbaugh, Diane L; Iwanowicz, Edwin J

2003-10-20

A series of novel small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH), based upon a 3-cyanoindole core, were explored. IMPDH catalyzes the rate determining step in guanine nucleotide biosynthesis and is a target for anticancer, immunosuppressive and antiviral therapy. The synthesis and the structure-activity relationships (SAR), derived from in vitro studies, for this new series of inhibitors is given.

Synthesis and structure-activity relationship of the first nonpeptidergic inverse agonists for the human cytomegalovirus encoded chemokine receptor US28.

Science.gov (United States)

Hulshof, Janneke W; Casarosa, Paola; Menge, Wiro M P B; Kuusisto, Leena M S; van der Goot, Henk; Smit, Martine J; de Esch, Iwan J P; Leurs, Rob

2005-10-06

US28 is a human cytomegalovirus (HCMV) encoded G-protein-coupled receptor that signals in a constitutively active manner. Recently, we identified 1 [5-(4-(4-chlorophenyl)-4-hydroxypiperidin-1-yl)-2,2-diphenylpentanenitrile] as the first reported nonpeptidergic inverse agonist for a viral-encoded chemokine receptor. Interestingly, this compound is able to partially inhibit the viral entry of HIV-1. In this study we describe the synthesis of 1 and several of its analogues and unique structure-activity relationships for this first class of small-molecule ligands for the chemokine receptor US28. Moreover, the compounds have been pharmacologically characterized as inverse agonists on US28. By modification of lead structure 1, it is shown that a 4-phenylpiperidine moiety is essential for affinity and activity. Other structural features of 1 are shown to be of less importance. These compounds define the first SAR of ligands on a viral GPCR (US28) and may therefore serve as important tools to investigate the significance of US28-mediated constitutive activity during viral infection.

Sexual dimorphism of the incidence of significant relationships between selected foot parameters and trunk parameters in children aged 7 – 13 years

Directory of Open Access Journals (Sweden)

Mirosław Mrozkowiak

2018-02-01

2.                  The number of trunk parameters with which the features of feet correlated most significantly was found to be bigger in male subjects than in their female counterparts. The features in boys revealed a more frequent significant relationship whereas the differentiating features were observed only in the frontal plane.

Performance evaluation recommendations of nuclear power plants outdoor significant civil structures earthquake resistance. Performance evaluation examples

International Nuclear Information System (INIS)

2005-06-01

The Japan Society of Civil Engineers has updated performance evaluation recommendations of nuclear power plants outdoor significant civil structures earthquake resistance in June 2005. Based on experimental and analytical considerations, analytical seismic models of soils for underground structures, effects of vertical motions on time-history dynamic analysis and shear fracture of reinforced concretes by cyclic loadings have been incorporated in new recommendations. This document shows outdoor civil structures earthquake resistance and endurance performance evaluation examples based on revised recommendations. (T. Tanaka)

Dysphagia disorders in patients with cancer of the oropharynx are significantly affected by the radiation therapy dose to the superior and middle constrictor muscle: A dose-effect relationship

International Nuclear Information System (INIS)

Levendag, Peter C.; Teguh, David N.; Voet, Peter; Est, Henri van der; Noever, Inge; Kruijf, Wilhelmus J.M. de; Kolkman-Deurloo, Inger-Karine; Prevost, Jean-Briac; Poll, Johan; Schmitz, Paul I.M.; Heijmen, Ben J.

2007-01-01

Purpose/Objective: To assess the relationship between the radiation therapy (RT) dose received by the muscular components of the swallowing (sw) apparatus and - dysphagia related - quality of life (QoL) in oropharyngeal cancer. Materials/Methods: Between 2000 and 2005, 81 patients with SCC of the oropharynx were treated by 3DCRT or IMRT, with or without concomitant chemotherapy (CHT); 43 out of these 81 patients were boosted by brachytherapy (BT). Charts of 81 patients were reviewed with regard to late dysphagia complaints; 23% experienced severe dysphagia. Seventeen patients expired. Fifty-six out of 64 (88%) responded to quality of life (QoL) questionnaires; that is, the Performance Status Scales of List, EORTC H and N35, and the M.D. Anderson Dysphagia Inventory. The superior (scm), middle (mcm), and inferior constrictor muscle (icm), the cricopharyngeus muscle and the inlet of the esophagus, are considered of paramount importance for swallowing. The mean dose was calculated in the muscular structures. Univariate analysis and multivariate analysis were performed using the proportional odds model. Results: Mean follow-up was 18 months (range 2-34) for IMRT, and 46 months for 3DCRT (range 2-72). At 3-years, a LRC of 84%, DFS of 78% and OS of 77% were observed. A significant correlation was observed between the mean dose in the scm and mcm, and severe dysphagia complaints (univariate analysis). A steep dose-effect relationship, with an increase of the probability of dysphagia of 19% with every additional 10 Gy, was established. In the multivariate analysis, BT (dose) was the only significant factor. Conclusion: A dose-effect relationship between dose and swallowing complaints was observed. One way to improve the QoL is to constrain the dose to be received by the swallowing muscles

The relationship between context, structure, and processes with outcomes of 6 regional diabetes networks in Europe

NARCIS (Netherlands)

Mahdavi, M. (Mahdi); J. Vissers (Jan); S. Elkhuizen (Sylvia); Van Dijk, M. (Mattees); Vanhala, A. (Antero); Karampli, E. (Eleftheria); R. Faubel (Raquel); P. Forte (Paul); Coroian, E. (Elena); J.J. van de Klundert (Joris)

2018-01-01

textabstractBackground While health service provisioning for the chronic condition Type 2 Diabetes (T2D) often involves a network of organisations and professionals, most evidence on the relationships between the structures and processes of service provisioning and the outcomes considers single

A Review of Recent Advances towards the Development of (Quantitative) Structure-Activity Relationships for Metallic Nanomaterials.

NARCIS (Netherlands)

Chen, Guangchao; Vijver, Martina G; Xiao, Yinlong; Peijnenburg, Willie J G M

2017-01-01

Gathering required information in a fast and inexpensive way is essential for assessing the risks of engineered nanomaterials (ENMs). The extension of conventional (quantitative) structure-activity relationships ((Q)SARs) approach to nanotoxicology, i.e., nano-(Q)SARs, is a possible solution. The

Structure Property Relationships in Organic Conjugated Systems

OpenAIRE

O'Neill, Luke; Lynch, Patrick; McNamara, Mary

2005-01-01

A series of π conjugated oligomers were studied by absorption and photoluminescence spectroscopy. A linear relationship between the positioning of the absorption and photoluminescence maxima plotted against inverse conjugation length is observed. The relationships are in good agreement with the simple particle in a box method, one of the earliest descriptions of the properties of one-dimensional organic molecules. In addition to the electronic transition energies, it was observed that the Sto...

Structure Property Relationships in Organic Conjugated Systems

OpenAIRE

O'Neill, Luke

2008-01-01

A series of pi(п) conjugated oligomers containing 1 to 6 monomer units were studied by absorption and photoluminescence spectroscopies. The results are discussed and examined with regard to the variation of the optical properties with the increase of effective conjugation length. It was found that there was a linear relationship between the positioning of the absorption and photoluminescence maxima plotted against inverse conjugation length. The relationships are in good agreement with the si...

Relationship characteristics of women in interracial same-sex relationships.

Science.gov (United States)

Jeong, Jae Y; Horne, Sharon G

2009-01-01

The purpose of this study was to examine the relationship characteristics of women in interracial same-sex relationships with respect to their current level of stress, internalized homophobia, perceived relationship equality, relationship satisfaction, and social support. Four groups were compared according to their current type of race relationship (ethnic minority women with White partners, White partners only, both ethnic minority partners, and White women with ethnic minority partners). No significant differences were found in terms of children and income; however, ethnic minority women with ethnic minority partners reported lower education attainment than the other groups. Relationally, there were no significant differences by race relationship for social support, relationship equality, relationship satisfaction, or stress. Internalized homophobia was lowest for interracial partnerships (ethnic minority paired with White partner). These findings are discussed in relationship to minority stress.

Performance evaluation recommendations and manuals of nuclear power plants outdoor significant civil structures earthquake resistance

International Nuclear Information System (INIS)

2005-06-01

Performance evaluation recommendations and manuals of nuclear power plants outdoor significant civil structures earthquake resistance have been updated in June 2005 by the Japan Society of Civil Engineers. Based on experimental and analytical considerations on the recommendations of May 2002, analytical seismic models of soils for underground structures, effects of vertical motions on time-history dynamic analysis and shear fracture of reinforced concretes by cyclic loadings have been evaluated and incorporated in new recommendations. (T. Tanaka)

A Mapping Between Structural and Functional Brain Networks.

Science.gov (United States)

Meier, Jil; Tewarie, Prejaas; Hillebrand, Arjan; Douw, Linda; van Dijk, Bob W; Stufflebeam, Steven M; Van Mieghem, Piet

2016-05-01

The relationship between structural and functional brain networks is still highly debated. Most previous studies have used a single functional imaging modality to analyze this relationship. In this work, we use multimodal data, from functional MRI, magnetoencephalography, and diffusion tensor imaging, and assume that there exists a mapping between the connectivity matrices of the resting-state functional and structural networks. We investigate this mapping employing group averaged as well as individual data. We indeed find a significantly high goodness of fit level for this structure-function mapping. Our analysis suggests that a functional connection is shaped by all walks up to the diameter in the structural network in both modality cases. When analyzing the inverse mapping, from function to structure, longer walks in the functional network also seem to possess minor influence on the structural connection strengths. Even though similar overall properties for the structure-function mapping are found for different functional modalities, our results indicate that the structure-function relationship is modality dependent.

Relationships between hormones and aggressive behavior in green anole lizards: an analysis using structural equation modeling.

Science.gov (United States)

Yang, Eun-Jin; Wilczynski, Walter

2002-09-01

We investigated the relationship between aggressive behavior and circulating androgens in the context of agonistic social interaction and examined the effect of this interaction on the androgen-aggression relationship in response to a subsequent social challenge in male Anolis carolinensis lizards. Individuals comprising an aggressive encounter group were exposed to an aggressive conspecific male for 10 min per day during a 5-day encounter period, while controls were exposed to a neutral stimulus for the same period. On the sixth day, their responses to an intruder test were observed. At intervals, individuals were sacrificed to monitor plasma androgen levels. Structural equation modeling (SEM) was used to test three a priori interaction models of the relationship between social stimulus, aggressive behavior, and androgen. Model 1 posits that exposure to a social stimulus influences androgen and aggressive behavior independently. In Model 2, a social stimulus triggers aggressive behavior, which in turn increases circulating levels of androgen. In Model 3, exposure to a social stimulus influences circulating androgen levels, which in turn triggers aggressive behavior. During the 5 days of the encounter period, circulating testosterone (T) levels of the aggressive encounter group followed the same pattern as their aggressive behavioral responses, while the control group did not show significant changes in their aggressive behavior or T level. Our SEM results supported Model 2. A means analysis showed that during the intruder test, animals with 5 days of aggressive encounters showed more aggressive responses than did control animals, while their circulating androgen levels did not differ. This further supports Model 2, suggesting that an animal's own aggressive behavior may trigger increases in levels of plasma androgen. Copyright 2002 Elsevier Science (USA)

Examining Structural Relationships between Work Engagement, Organizational Procedural Justice, Knowledge Sharing, and Innovative Work Behavior for Sustainable Organizations

Directory of Open Access Journals (Sweden)

Woocheol Kim

2017-02-01

Full Text Available Despite the importance of the human/social dimension of organizational sustainability, this area of scholastic endeavor has received relatively little attention when compared to the economic and environmental dimensions of sustainability. On the basis of social exchange theory, this study posited the important role that employee work engagement is a key component for improving human performance for organizational sustainability. In order to do so, it suggests the important role that employee work engagement has on the relationships among various factors in the organization, including organizational procedural justice, knowledge sharing, and innovative work behaviors. A total of 400 complete responses from full-time employees in Korean organizations were used for the purpose of data analysis with structural equation modeling (SEM. The results demonstrated that organizational procedural justice is positively related with employee work engagement, knowledge sharing, and innovative work behavior. In addition, work engagement enhances employee knowledge sharing and innovative work behavior, and knowledge sharing enhances innovative work behavior. With regard to the mechanisms of these relationships, work engagement and knowledge sharing acted as significant mediators. Based on the findings, we suggested relevant research implications and recommendations for future research on sustainable organizations.

Molecular Descriptors Family on Structure Activity Relationships 6. Octanol-Water Partition Coefficient of Polychlorinated Biphenyls

Directory of Open Access Journals (Sweden)

Lorentz JÄNTSCHI

2006-01-01

Full Text Available Octanol-water partition coefficient of two hundred and six polychlorinated biphenyls was model by the use of an original method based on complex information obtained from compounds structure. The regression analysis shows that best results are obtained in four-varied model (r2 = 0.9168. The prediction ability of the model was studied through leave-one-out analysis (r2cv(loo = 0.9093 and in training and test sets analysis. Modeling the octanol-water partition coefficient of polychlorinated biphenyls by integration of complex structural information provide a stable and performing four-varied model, allowing us to make remarks about relationship between structure of polychlorinated biphenyls and associated octanol-water partition coefficients.

The Relationship of Bureaucratic Structure to School Climate: An Exploratory Factor Analysis of Construct Validity

Science.gov (United States)

Lennon, Patricia A.

2010-01-01

This researcher examined the relationship of bureaucratic structure to school climate by means of an exploratory factor analysis of a measure of bureaucracy developed by Hoy and Sweetland (2000) and the four dimensional measure of climate developed by Hoy, Smith, and Sweetland (2002). Since there had been no other empirical studies whose authors…

Quantitative structure activity relationship (QSAR) of piperine analogs for bacterial NorA efflux pump inhibitors.

Science.gov (United States)

Nargotra, Amit; Sharma, Sujata; Koul, Jawahir Lal; Sangwan, Pyare Lal; Khan, Inshad Ali; Kumar, Ashwani; Taneja, Subhash Chander; Koul, Surrinder

2009-10-01

Quantitative structure activity relationship (QSAR) analysis of piperine analogs as inhibitors of efflux pump NorA from Staphylococcus aureus has been performed in order to obtain a highly accurate model enabling prediction of inhibition of S. aureus NorA of new chemical entities from natural sources as well as synthetic ones. Algorithm based on genetic function approximation method of variable selection in Cerius2 was used to generate the model. Among several types of descriptors viz., topological, spatial, thermodynamic, information content and E-state indices that were considered in generating the QSAR model, three descriptors such as partial negative surface area of the compounds, area of the molecular shadow in the XZ plane and heat of formation of the molecules resulted in a statistically significant model with r(2)=0.962 and cross-validation parameter q(2)=0.917. The validation of the QSAR models was done by cross-validation, leave-25%-out and external test set prediction. The theoretical approach indicates that the increase in the exposed partial negative surface area increases the inhibitory activity of the compound against NorA whereas the area of the molecular shadow in the XZ plane is inversely proportional to the inhibitory activity. This model also explains the relationship of the heat of formation of the compound with the inhibitory activity. The model is not only able to predict the activity of new compounds but also explains the important regions in the molecules in quantitative manner.

Estimating Tropical Forest Structure Using a Terrestrial Lidar.

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Michael Palace

Full Text Available Forest structure comprises numerous quantifiable biometric components and characteristics, which include tree geometry and stand architecture. These structural components are important in the understanding of the past and future trajectories of these biomes. Tropical forests are often considered the most structurally complex and yet least understood of forested ecosystems. New technologies have provided novel avenues for quantifying biometric properties of forested ecosystems, one of which is LIght Detection And Ranging (lidar. This sensor can be deployed on satellite, aircraft, unmanned aerial vehicles, and terrestrial platforms. In this study we examined the efficacy of a terrestrial lidar scanner (TLS system in a tropical forest to estimate forest structure. Our study was conducted in January 2012 at La Selva, Costa Rica at twenty locations in a predominantly undisturbed forest. At these locations we collected field measured biometric attributes using a variable plot design. We also collected TLS data from the center of each plot. Using this data we developed relative vegetation profiles (RVPs and calculated a series of parameters including entropy, Fast Fourier Transform (FFT, number of layers and plant area index to develop statistical relationships with field data. We developed statistical models using a series of multiple linear regressions, all of which converged on significant relationships with the strongest relationship being for mean crown depth (r2 = 0.88, p < 0.001, RMSE = 1.04 m. Tree density was found to have the poorest significant relationship (r2 = 0.50, p < 0.01, RMSE = 153.28 n ha-1. We found a significant relationship between basal area and lidar metrics (r2 = 0.75, p < 0.001, RMSE = 3.76 number ha-1. Parameters selected in our models varied, thus indicating the potential relevance of multiple features in canopy profiles and geometry that are related to field-measured structure. Models for biomass estimation included

Estimating Tropical Forest Structure Using a Terrestrial Lidar.

Science.gov (United States)

Palace, Michael; Sullivan, Franklin B; Ducey, Mark; Herrick, Christina

2016-01-01

Forest structure comprises numerous quantifiable biometric components and characteristics, which include tree geometry and stand architecture. These structural components are important in the understanding of the past and future trajectories of these biomes. Tropical forests are often considered the most structurally complex and yet least understood of forested ecosystems. New technologies have provided novel avenues for quantifying biometric properties of forested ecosystems, one of which is LIght Detection And Ranging (lidar). This sensor can be deployed on satellite, aircraft, unmanned aerial vehicles, and terrestrial platforms. In this study we examined the efficacy of a terrestrial lidar scanner (TLS) system in a tropical forest to estimate forest structure. Our study was conducted in January 2012 at La Selva, Costa Rica at twenty locations in a predominantly undisturbed forest. At these locations we collected field measured biometric attributes using a variable plot design. We also collected TLS data from the center of each plot. Using this data we developed relative vegetation profiles (RVPs) and calculated a series of parameters including entropy, Fast Fourier Transform (FFT), number of layers and plant area index to develop statistical relationships with field data. We developed statistical models using a series of multiple linear regressions, all of which converged on significant relationships with the strongest relationship being for mean crown depth (r2 = 0.88, p < 0.001, RMSE = 1.04 m). Tree density was found to have the poorest significant relationship (r2 = 0.50, p < 0.01, RMSE = 153.28 n ha-1). We found a significant relationship between basal area and lidar metrics (r2 = 0.75, p < 0.001, RMSE = 3.76 number ha-1). Parameters selected in our models varied, thus indicating the potential relevance of multiple features in canopy profiles and geometry that are related to field-measured structure. Models for biomass estimation included structural canopy

Structure-function relationships with spectral-domain optical coherence tomography retinal nerve fiber layer and optic nerve head measurements.

Science.gov (United States)

Pollet-Villard, Frédéric; Chiquet, Christophe; Romanet, Jean-Paul; Noel, Christian; Aptel, Florent

2014-05-02

To evaluate the regional structure-function relationship between visual field sensitivity and retinal nerve fiber layer (RNFL) thickness and optic nerve head (ONH) measurements using spectral-domain optical coherence tomography (SD-OCT). Prospective cross-sectional study conducted on patients with glaucoma, suspected glaucoma, and healthy subjects. Eyes were tested on Cirrus OCT and standard achromatic perimetry. RNFL thickness of 12 peripapillary 30° sectors, neuroretinal rim thickness extracted from 36 neuroretinal rim scans, and Bruch membrane opening minimum rim width (BMO-MRW)-a recently defined parameter-extracted from 36 neuroretinal rim scans were obtained. Correlations between peripapillary RNFL thickness, neuroretinal rim thickness, all six sectors of BMO-MRW, and visual field sensitivity in the six corresponding areas were evaluated using logarithmic regression analysis. Receiver operating curve areas were calculated for each RNFL, ONH, and macular ganglion cell analysis parameter. We included 142 eyes of 142 subjects. The correlations (r(2)) between RNFL thickness, Cirrus-based neuroretinal rim thickness, BMO-MRW and visual field sensitivity ranged from 0.07 to 0.60, 0.15 to 0.49, and 0.24 to 0.66, respectively. The structure-function correlations were stronger with BMO-MRW than with Cirrus-based neuroretinal rim thickness. The largest areas under the receiver operating curve were seen for rim area (0.926 [95% confidence interval 0.875, 0.977]; P function relationship was significantly stronger with BMO-MRW than other ONH SD-OCT parameters. The best diagnostic capabilities were seen with rim area and average RNFL.

The relationship between cognitive processing of affective verbal material and the basic personality structure

Directory of Open Access Journals (Sweden)

Orlić Ana

2010-01-01

Full Text Available The aim of this study was to investigate the relationship between cognitive processing of affective verbal material and the basic personality structure. For the purposes of research a new experiment was created, where affective priming was measured in a lexical decision task. The term affective priming stands for facilitation in recognition of the stimuli that comes after the presentation of stimuli of the same valence. In this experiment, two words were presented on a screen in front of the subject (stimuli-prime and stimuli-target. Those two words were of the same or different affective valence, and the subject's were instructed to respond whether the second word on the screen had a meaning or not. The basic personality structure was defined by the 'Big five' model and the Disintegration model and measured by NEO PI-R and Delta 10 questionnaires. The results of the affective priming experiment indicated a strong effect of positive facilitation and much weaker effect off negative facilitation. Two significant functions were extracted by quasicanonical correlation analysis. The first function showed correlation between the effect of positive facilitation and all of the subscales of Neuroticism, Extraversion and Conscientiousness (NEO PI-R, as well as all sub dimensions of Disintegration (DELTA 10. The second one indicated to a correlation between the negative facilitation effect and some subscales of Neuroticism, Extraversion and Agreeableness (NEO PI-R, as well as all subscales of Disintegration (DELTA 10.

Relationship Dissolution and Psychologically Aggressive Dating Relationships: Preliminary Findings From a College-Based Relationship Education Course.

Science.gov (United States)

Negash, Sesen; Cravens, Jaclyn D; Brown, Preston C; Fincham, Frank D

This study evaluated the impact of a relationship education program, delivered as part of a college course, among students (N = 152) who reported experiencing psychological aggression in their exclusive dating relationship. Preliminary results showed that compared to those in the control group, participants receiving relationship education were significantly more likely to end their romantic relationship, even after controlling for relationship satisfaction. Furthermore, when relationship termination occurred, those in the intervention group were significantly more likely to attribute the breakup to their participation in the class as compared to those in the control group. The tentative findings are an important preliminary step in assessing the benefits of relationship education in reducing the risk of psychological aggression among college students.

[Phytoplankton's community structure and its relationships with environmental factors in the rivers of Tongling City, Anhui Province of East China in winter].

Science.gov (United States)

Wang, Li; Wei, Wei; Zhou, Ping; Li, Yang; Sun, Qing-Ye

2013-01-01

Tongling is one of the main non-ferrous metal mining areas in China, and the biodiversity in the river ecosystem of this area is seriously affected by heavy metals as a result of mining activities. In the winter in 2010, an investigation was conducted on the community structure of phytoplankton and its relationships with environmental factors in the main sections of the rivers in Tongling. A total of 203 phytoplankton species were identified, belonging to 96 genera and 8 phyla. The community structure of the phytoplankton differed obviously in different river sections, but the communities were all dominated by Bacillariophyta, Chlorophyta and Cyanophyta. The phytoplankton abundance ranged from 9.1 x 10(3) to 6.5 x 10(7) cells x L(-1), and the quantity of the phytoplankton in the river sections directly carried with mining waste water was significantly low. The Shannon index of the phytoplankton community at different sampling sites ranged from 0 to 3.45, with a significant discrepancy in different river sections. There existed significant correlations between the density and group number of phytoplankton and the COD(Cr) and cadmium, copper and zinc concentrations in the rivers, and the concentrations of river total nitrogen, NH4(+)-N, NO3(-)-N, and copper, COD(Cr) and pH were the main environmental variables affecting the phytoplankton' s community structure and its spatial distribution. Although the nutritional status of the river waters had greater effects on the community structure of phytoplankton, the effects of the heavy metals there from mining enterprises could not be neglected.

Customer over employee? : the implications of Customer Relationship Management (CRM) for organisational structures and labour quality

NARCIS (Netherlands)

Kwakkelstein, T.

2002-01-01

This paper for the Emergence WWWe (The World, the Workplace and We, the workers)-Conference E-Work in a Global World, Brussels 16 & 17 April 2002, explores the effects of the increasing popular ICT application suite Customer Relationship Management (CRM) on organisational structures, corporate

Exploring the relationships among performance-based functional ability, self-rated disability, perceived instrumental support, and depression: a structural equation model analysis.

Science.gov (United States)

Weil, Joyce; Hutchinson, Susan R; Traxler, Karen

2014-11-01

Data from the Women's Health and Aging Study were used to test a model of factors explaining depressive symptomology. The primary purpose of the study was to explore the association between performance-based measures of functional ability and depression and to examine the role of self-rated physical difficulties and perceived instrumental support in mediating the relationship between performance-based functioning and depression. The inclusion of performance-based measures allows for the testing of functional ability as a clinical precursor to disability and depression: a critical, but rarely examined, association in the disablement process. Structural equation modeling supported the overall fit of the model and found an indirect relationship between performance-based functioning and depression, with perceived physical difficulties serving as a significant mediator. Our results highlight the complementary nature of performance-based and self-rated measures and the importance of including perception of self-rated physical difficulties when examining depression in older persons. © The Author(s) 2014.

Bulk-surface relationship of an electronic structure for high-throughput screening of metal oxide catalysts

International Nuclear Information System (INIS)

Kweun, Joshua Minwoo; Li, Chenzhe; Zheng, Yongping; Cho, Maenghyo; Kim, Yoon Young; Cho, Kyeongjae

2016-01-01

Graphical abstract: - Highlights: • Bulk-surface relationship was predicted by the ligand field nature of metal oxides. • Antibonding and bonding d-bands occupancy clarified the bulk-surface relationship. • Different surface relaxations were explained by the bulk electronic structures. • Transition from the bulk to the surface state was simulated by oxygen adsorption. - Abstract: Designing metal-oxides consisting of earth-abundant elements has been a crucial issue to replace precious metal catalysts. To achieve efficient screening of metal-oxide catalysts via bulk descriptors rather than surface descriptors, we investigated the relationship between the electronic structure of bulk and that of the surface for lanthanum-based perovskite oxides, LaMO_3 (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu). Through density functional theory calculations, we examined the d-band occupancy of the bulk and surface transition-metal atoms (n_B_u_l_k and n_S_u_r_f) and the adsorption energy of an oxygen atom (E_a_d_s) on (001), (110), and (111) surfaces. For the (001) surface, we observed strong correlation between the n_B_u_l_k and n_S_u_r_f with an R-squared value over 94%, and the result was interpreted in terms of ligand field splitting and antibonding/bonding level splitting. Moreover, the E_a_d_s on the surfaces was highly correlated with the n_B_u_l_k with an R-squared value of more than 94%, and different surface relaxations could be explained by the bulk electronic structure (e.g., LaMnO_3 vs. LaTiO_3). These results suggest that a bulk-derived descriptor such as n_B_u_l_k can be used to screen metal-oxide catalysts.

Structural and functional measures of social relationships and quality of life among older adults: does chronic disease status matter?

Science.gov (United States)

Liao, Jing; Brunner, Eric J

2016-01-01

To evaluate the relative importance of structural and functional social relationships for quality of life (QoL) and the extent to which diagnosed chronic disease modifies these associations. Multivariate linear regression was used to investigate time-lagged associations between structural and functional measures of social relationships and QoL assessed 5 years apart by CASP-19, in 5925 Whitehall II participants (mean age 61, SD 6.0). Chronic disease was clinically verified coronary heart disease, stroke, diabetes or cancer. Social relationships-QoL associations were consistent across disease status (P-values for interaction: 0.15-0.99). Larger friend network (β = 1.9, 95% CI 1.5-2.3), having a partner (β = 1.2, 95% CI 0.5-1.7), higher confiding support (β = 2.2, 95% CI 1.8-2.7) and lower negative aspects of close relationships (β = 3.3, 95% CI 2.8-3.8) were independently related to improved QoL in old age. The estimated difference in QoL due to social relationships was equivalent to up to 0.5 SD of the CASP-19 score and was stronger than the effect of chronic disease (coronary heart disease β = 2.0, 95% CI 1.4-2.6). We found that beneficial aspects of social relationships in relation to QoL were, in order of importance: avoiding negative aspects of close relationships, having confiding support, having a wide network of friends and having a partner. These associations were not modified by chronic disease. Thus, despite inevitable physical deterioration, we may be able to enhance a satisfying late life by optimizing our social relationships.

Structural and functional significance of water permeation through cotransporters

DEFF Research Database (Denmark)

Zeuthen, Thomas; Gorraitz, Edurne; Her, Ka

2016-01-01

Membrane transporters, in addition to their major role as specific carriers for ions and small molecules, can also behave as water channels. However, neither the location of the water pathway in the protein nor their functional importance is known. Here, we map the pathway for water and urea...... through the intestinal sodium/glucose cotransporter SGLT1. Molecular dynamics simulations using the atomic structure of the bacterial transporter vSGLT suggest that water permeates the same path as Na+ and sugar. On a structural model of SGLT1, based on the homology structure of vSGLT, we identified...... to be due to alterations in steric hindrance to water and urea, and/or changes in protein folding caused by mismatching of side chains in the water pathway. Water permeation through SGLT1 and other transporters bears directly on the structural mechanism for the transport of polar solutes through...

Quantitative Structure-Retention Relationships (QSRR) for Chromatographic Separation of Disazo and Trisazo 4,4'-Diaminobenzanilide-based Dyes

OpenAIRE

Funar-Timofei, Simona; Fabian, Walter M. F.; Simu, Georgeta M.; Suzukic, Takahiro

2006-01-01

For a series of 23 disazo and trisazo 4,4'-diaminobenzanilide-based direct dye molecules, thechromatographic mobilities, extrapolated to modifier-free conditions (RM0 values), were determinedfrom reverse-phase thin-layer chromatography (RP-TLC) experiments. Traditional and rational QSAR/QSPR modelling techniques have been applied to find a quantitative structure-retention relationship (QSRR) for the dyes. Molecular dye structures were energy minimized by both molecular mechanics and quantum c...

Significance of Alkali-Silica reaction in nuclear safety-related concrete structures

International Nuclear Information System (INIS)

Le Pape, Y.; Field, K.G.; Mattus, C.H.; Naus, D.J.; Busby, J.T.; Saouma, V.; Ma, Z.J.; Cabage, J.V.; Guimaraes, M.

2015-01-01

Nuclear Power Plant license renewal up to 60 years and possible life extension beyond has established a renewed focus on long-term aging of nuclear generating stations materials, and particularly, on concrete. Large irreplaceable sections of most nuclear generating stations include concrete components. The Expanded Materials Degradation Analysis, jointly performed by the Department of Energy, the U.S. Nuclear Regulatory Commission, the Academia and the Power Generation Industry, identified the need to develop a consistent knowledge base of alkali-silica reaction (ASR) within concrete as an urgent priority (Graves et al., 2014). ASR results in an expansion of Concrete produced by the reaction between alkali (generally from cement), reactive aggregate (like amorphous silica) and water absorption. ASR causes expansion, cracking and loss of mechanical properties. Considering that US commercial reactors in operation enter the age when ASR distress can be potentially observed and that numerous non-nuclear infrastructures (transportation, energy production) in a majority of the States have already experienced ASR-related concrete degradation, the susceptibility and significance of ASR for nuclear concrete structures must be addressed. This paper outlines an on-going research program including the investigation of the possibility of ASR in nuclear power plants, and the assessment of the residual shear bearing capacity of ASR-subjected nuclear structures. (authors)

Structure-Activity Relationship Studies of the Cyclic Depsipeptide Natural Product YM-254890, Targeting the Gq Protein

DEFF Research Database (Denmark)

Zhang, Hang; Xiong, Xiao-feng; Boesgaard, Michael W

2017-01-01

that specifically inhibit signaling mediated by the Gq subfamily. In this study we exploit a newly developed synthetic strategy for this compound class in the design, synthesis, and pharmacological evaluation of eight new analogues of YM-254890. These structure-activity relationship studies led to the discovery...

Investigations on the structure – Property relationships of electron beam welded Inconel 625 and UNS 32205

International Nuclear Information System (INIS)

Devendranath Ramkumar, K.; Sridhar, R.; Periwal, Saurabh; Oza, Smitkumar; Saxena, Vimal; Hidad, Preyas; Arivazhagan, N.

2015-01-01

Highlights: • Joining of dissimilar metals of Inconel 625 and UNS S32205 using electron beam welding. • Detailed structure – property relationship of dissimilar welds. • Improved metallurgical and tensile properties from the EB welding. - Abstract: The metallurgical and mechanical properties of electron beam welded Ni based superalloy Inconel 625 and UNS S32205 duplex stainless steel plates have been investigated in the present study. Interface microstructure studies divulged the absence of any grain coarsening effects or the formation of any secondary phases at the heat affected zone (HAZ) of the electron beam (EB) weldments. Tensile studies showed that the fracture occurred at the weld zone in all the trials and the average weld strength was reported to be 850 MPa. Segregation of Mo rich phases was witnessed at the inter-dendritic arms of the fusion zone. The study recommended the use of EB welding for joining these dissimilar metals by providing detailed structure – property relationships

Is better beautiful or is beautiful better? Exploring the relationship between beauty and category structure.

Science.gov (United States)

Sanders, Megan; Davis, Tyler; Love, Bradley C

2013-06-01

We evaluate two competing accounts of the relationship between beauty and category structure. According to the similarity-based view, beauty arises from category structure such that central items are favored due to their increased fluency. In contrast, the theory-based view holds that people's theories of beauty shape their perceptions of categories. In the present study, subjects learned to categorize abstract paintings into meaningfully labeled categories and rated the paintings' beauty, value, and typicality. Inconsistent with the similarity-based view, beauty ratings were highly correlated across conditions despite differences in fluency and assigned category structure. Consistent with the theory-based view, beautiful paintings were treated as central members for categories expected to contain beautiful paintings (e.g., art museum pieces), but not in others (e.g., student show pieces). These results suggest that the beauty of complex, real-world stimuli is not determined by fluency within category structure but, instead, interacts with people's prior knowledge to structure categories.

Relative Power in Sibling Relationships Across Adolescence.

Science.gov (United States)

Lindell, Anna K; Campione-Barr, Nicole

2017-06-01

During childhood, older siblings typically hold a more powerful position in their relationship with their younger siblings, but these relationships are thought to become more egalitarian during adolescence as siblings begin to prepare for their relationships as adults and as younger siblings become more socially and cognitively competent. Little is known about relationship factors that may explain this shift in power dynamics, however. The present study therefore examined longitudinal changes in adolescents' and their siblings' perceptions of sibling relative power from age 12 to 18 (n = 145 dyads), and examined whether different levels of sibling relationship positivity and negativity, as well as sibling structural variables, indicated different over-time changes in relative power. Multilevel models indicated that adolescents reported significant declines in their siblings' relative power across adolescence, with older siblings relinquishing the most power over time. However, only siblings with less positively involved relationships reported declines in relative power, suggesting that siblings who maintain highly involved relationships may not become more egalitarian during adolescence. © 2017 Wiley Periodicals, Inc.

Quantitative Structure Activity Relationship of Cinnamaldehyde Compounds against Wood-Decaying Fungi

Directory of Open Access Journals (Sweden)

Dongmei Yang

2016-11-01

Full Text Available Cinnamaldehyde, of the genius Cinnamomum, is a major constituent of the bark of the cinnamon tree and possesses broad-spectrum antimicrobial activity. In this study, we used best multiple linear regression (BMLR to develop quantitative structure activity relationship (QSAR models for cinnamaldehyde derivatives against wood-decaying fungi Trametes versicolor and Gloeophyllun trabeum. Based on the two optimal QSAR models, we then designed and synthesized two novel cinnamaldehyde compounds. The QSAR models exhibited good correlation coefficients: R2Tv = 0.910 for Trametes versicolor and R2Gt = 0.926 for Gloeophyllun trabeum. Small errors between the experimental and calculated values of two designed compounds indicated that these two QSAR models have strong predictability and stability.

Analysis of moment structures for assessing relationships among perceived chewing ability, dentition status, muscle strength, and balance in community-dwelling older adults.

Science.gov (United States)

Moriya, Shingo; Notani, Kenji; Murata, Ayumi; Inoue, Nobuo; Miura, Hiroko

2014-12-01

The aim of this study was to assess relationships among perceived chewing ability, dentition status, muscle strength and balance in community-dwelling older adults using analysis of moment structures (Amos). Physical performance parameters such as muscle strength and balance can predict the future onset of disabilities in activities of daily living among older adults. In this context, elucidation of the relationships among oral conditions and physical performance parameters is necessary. Data on occlusal contact patterns of natural teeth (OPNT), self-assessed masticatory ability (mastication), body mass index (BMI), handgrip strength (HG) and one-leg standing time with eyes open (OLST) were collected from 501 independently living adults aged 65-74 years. The relationships among these parameters were analysed using Spearman's rank correlation coefficients and Amos. Subjects of both genders showed significant correlations among OPNT, mastication, HG and OLST, evaluated using Spearman's rank correlation coefficients. For each Amos model, the goodness-of-fit statistic indicated a good level of fit. In both men and women, OPNT was significantly related to mastication, and mastication was related to HG but not to OLST. OPNT was related to neither HG nor OLST in women and was related to OLST but not HG in men. The findings observed in this study present a possible importance of dental status and perceived chewing ability for the onset of disability by influencing physical performance in community-dwelling older adults. © 2012 The Gerodontology Society and John Wiley & Sons A/S.

Red Wine Tannin Structure-Activity Relationships during Fermentation and Maceration.

Science.gov (United States)

Yacco, Ralph S; Watrelot, Aude A; Kennedy, James A

2016-02-03

The correlation between tannin structure and corresponding activity was investigated by measuring the thermodynamics of interaction between tannins isolated from commercial red wine fermentations and a polystyrene divinylbenzene HPLC column. Must and/or wine samples were collected throughout fermentation/maceration from five Napa Valley wineries. By varying winery, fruit source, maceration time, and cap management practice, it was considered that a reasonably large variation in commercially relevant tannin structure would result. Tannins were isolated from samples collected using low pressure chromatography and were then characterized by gel permeation chromatography and acid-catalyzed cleavage in the presence of excess phloroglucinol (phloroglucinolysis). Corresponding tannin activity was determined using HPLC by measuring the thermodynamics of interaction between isolated tannin and a polystyrene divinylbenzene HPLC column. This measurement approach was designed to determine the ability of tannins to hydrophobically interact with a hydrophobic surface. The results of this study indicate that tannin activity is primarily driven by molecular size. Compositionally, tannin activity was positively associated with seed tannins and negatively associated with skin and pigmented tannins. Although measured indirectly, the extent of tannin oxidation as determined by phloroglucinolysis conversion yield suggests that tannin oxidation at this stage of production reduces tannin activity. Based upon maceration time, this study indicates that observed increases in perceived astringency quality, if related to tannin chemistry, are driven by tannin molecular mass as opposed to pigmented tannin formation or oxidation. Overall, the results of this study give new insight into tannin structure-activity relationships which dominate during extraction.

Relationship between structure and antiproliferative activity of polymethoxyflavones towards HL60 cells.

Science.gov (United States)

Kawaii, Satoru; Ikuina, Tomoyasu; Hikima, Takeshi; Tokiwano, Tetsuo; Yoshizawa, Yuko

2012-12-01

As part of our continuing investigation of polymethoxyflavone (PMF) derivatives as potential anticancer substances, a series of PMF derivatives was synthesized. The synthesized compounds were evaluated for cytotoxicity against the promyelocytic leukemic HL60 cell line, and structure-activity relationship correlations were investigated along with previously isolated PMFs from the peel of king orange (Citrus nobilis). 7,3'-Dimethoxyflavone demonstrated the most potent activity among the synthetic PMFs. Consideration of correlation between the methoxylation pattern and antiproliferative activity revealed the importance of the 3'-methoxyl group and the higher degree of methoxylation on the A-ring moiety of PMFs.

Electron-topological investigation of the structure-antitumor activity relationship of thiosemicarbazone derivatives.

Science.gov (United States)

Dimoglo, A S; Chumakov, Y M; Dobrova, B N; Saracoglu, M

1997-04-01

In the frameworks of the electron-topological method (ETM) the structure-antitumor activity relationship was investigated for a series of thiosemicarbazone derivatives. The series included 70 compounds. Conformational analysis and quantum-chemical calculations were carried out for each compound. The revealed activity feature showed a satisfactory description of the class of active compounds according to two different parameters P and alpha estimating the probabilities of the feature realization in the class of active compounds (they are equal to 0.94 and 0.86, correspondingly). The results of testing demonstrated the high ability of ETM in predicting the activity investigated.

Synthesis and Structure-Activity Relationships of a Series of Aporphine Derivatives with Antiarrhythmic Activities and Acute Toxicity

Directory of Open Access Journals (Sweden)

Hui Wang

2016-11-01

Full Text Available Some aporphine alkaloids, such as crebanine, were found to present arrhythmic activity and also higher toxicity. A series of derivatives were synthesized by using three kinds of aporphine alkaloids (crebanine, isocorydine, and stephanine as lead compounds. Chemical methods, including ring-opening reaction, bromination, methylation, acetylation, quaternization, and dehydrogenation, were adopted. Nineteen target derivatives were evaluated for their antiarrhythmic potential in the mouse model of ventricular fibrillation (VF, induced by CHCl3, and five of the derivatives were investigated further in the rat model of arrhythmia, induced by BaCl2. Meanwhile, preliminary structure-activity/toxicity relationship analyses were carried out. Significantly, N-acetamidesecocrebanine (1d, three bromo-substituted products of crebanine (2a, 2b, 2c, N-methylcrebanine (2d, and dehydrostephanine (4a displayed antiarrhythmic effects in the CHCl3-induced model. Among them, 7.5 mg/kg of 2b was able to significantly reduce the incidence of VF induced by CHCl3 (p < 0.05, increase the number of rats that resumed sinus rhythm from arrhythmia, induced by BaCl2 (p < 0.01, and the number of rats that maintained sinus rhythm for more than 20 min (p < 0.01. Therefore, 2b showed remarkably higher antiarrhythmic activity and a lower toxicity (LD50 = 59.62 mg/kg, mice, simultaneously, indicating that 2b could be considered as a promising candidate in the treatment of arrhythmia. Structural-activity analysis suggested that variationsin antiarrhythmic efficacy and toxicity of aporphines were related to the C-1,C-2-methylenedioxy group on ring A, restricted ring B structural conformation, N-quaternization of ring B, levoduction of 6a in ring C, and the 8-, 9-, 10-methoxy groups on ring D on the skeleton.

Students' Demand for Smartphones: Structural Relationships of Product Features, Brand Name, Product Price and Social Infuence

Science.gov (United States)

Suki, Norazah Mohd

2013-01-01

Purpose: The study aims to examine structural relationships of product features, brand name, product price and social influence with demand for Smartphones among Malaysian students'. Design/methodology/approach: Data collected from 320 valid pre-screened university students studying at the pubic higher learning institution in Federal Territory of…

The Relationship between Structural Dimensions of Personality and School Life in Adolescence

Directory of Open Access Journals (Sweden)

Renato G. Carvalho

2014-01-01

Full Text Available In this cross-sectional study, we analyse the relationship between personality, which was operationalized in the PSY-5 dimensions of the Minnesota Multiphasic Personality Inventory - Adolescent (MMPI-A and the way students live their lives at school, expressed through indicators of achievement, integration, and overall satisfaction. A total of 351 students, aged 14-18 years, participated in the study. The instruments were the Portuguese version of the MMPI-A and the School Life Questionnaire. Results show a pattern of significant relationships between personality traits and school life, being Disconstraint and Introversion the personality dimensions that stood out mostly in the explanation of school life variables results. Results are analysed considering the importance of personality for the development of more or less adaptive pathways in adolescence.

Finding the most significant common sequence and structure motifs in a set of RNA sequences

DEFF Research Database (Denmark)

Gorodkin, Jan; Heyer, L.J.; Stormo, G.D.

1997-01-01

We present a computational scheme to locally align a collection of RNA sequences using sequence and structure constraints, In addition, the method searches for the resulting alignments with the most significant common motifs, among all possible collections, The first part utilizes a simplified...

The couple relationship - support functions and sexuality in Old Age

Directory of Open Access Journals (Sweden)

Claudia Josefina Arias

2013-12-01

Full Text Available The aim of this paper is to analyze: 1 couple relationships – support functions and characteristics of the relationships – and their difference by gender, and 2 changes that occur in those relationships and in sexual activity in older heterosexual adults in the 65-85 age range. The subjects of the analysis were intentionally selected and the data has been collected in structured and semi-structured interviews. The results obtained by quantitative and qualitative analysis show that the couple relationship in old age fulfills functions such as emotional support, companionship and cognitive advice. Analysis by gender shows significant differences in 4 out of the 5 support functions that were explored. Among the changes that take place in old age, the decrease of frequency in sexual activity appears in the first place, though the level of satisfaction is maintained; and fellowship, mutual care and positive affect in relation to the partner increase.

Proximity and Distance in Knowledge Relationships : From Micro to Structural Considerations based on Territorial Knowledge Dynamics (TKDs)

NARCIS (Netherlands)

Crespo, Joan; Vicente, Jérôme

2016-01-01

Crespo J. and Vicente J. Proximity and distance in knowledge relationships: from micro to structural considerations based on territorial knowledge dynamics (TKDs), Regional Studies. Among the key parameters identified in territorial knowledge dynamics (TKDs), this paper focuses on the balance and

Relationships between bat occupancy and habitat and landscape structure along a savanna, woodland, forest gradient in the Missouri Ozarks

Science.gov (United States)

Clarissa A. Starbuck; Sybill K. Amelon; Frank R. III. Thompson

2015-01-01

Many land-management agencies are restoring savannas and woodlands using prescribed fire and forest thinning, and information is needed on how wildlife species respond to these management activities. Our objectives were to evaluate support for relationships of bat site occupancy with vegetation structure and management and landscape composition and structure across a...

Structural protein relationships among eastern equine encephalitis viruses.

Science.gov (United States)

Strizki, J M; Repik, P M

1994-11-01

We have re-evaluated the relationships among the polypeptides of eastern equine encephalitis (EEE) viruses using SDS-PAGE and peptide mapping of individual virion proteins. Four to five distinct polypeptide bands were detected upon SDS-PAGE analysis of viruses: the E1, E2 and C proteins normally associated with alphavirus virions, as well as an additional more rapidly-migrating E2-associated protein and a high M(r) (HMW) protein. In contrast with previous findings by others, the electrophoretic profiles of the virion proteins of EEE viruses displayed a marked correlation with serotype. The protein profiles of the 33 North American (NA)-serotype viruses examined were remarkably homogeneous, with variation detected only in the E1 protein of two isolates. In contrast, considerable heterogeneity was observed in the migration profiles of both the E1 and E2 glycoproteins of the 13 South American (SA)-type viruses examined. Peptide mapping of individual virion proteins using limited proteolysis with Staphylococcus aureus V8 protease confirmed that, in addition to the homogeneity evident among NA-type viruses and relative heterogeneity among SA-type viruses, the E1 and E2 proteins of NA- and SA-serotype viruses exhibited serotype-specific structural variation. The C protein was highly conserved among isolates of both virus serotypes. Endoglycosidase analyses of intact virions did not reveal substantial glycosylation differences between the glycoproteins of NA- and SA-serotype viruses. Both the HMW protein and the E2 protein (doublet) of EEE virus appeared to contain, at least in part, high-mannose type N-linked oligosaccharides. No evidence of O-linked glycans was found on either the E1 or the E2 glycoprotein. Despite the observed structural differences between proteins of NA- and SA-type viruses, Western blot analyses utilizing polyclonal antibodies indicated that immunoreactive epitopes appeared to be conserved.

Determination of structural fluctuations of proteins from structure-based calculations of residual dipolar couplings

International Nuclear Information System (INIS)

Montalvao, Rinaldo W.; De Simone, Alfonso; Vendruscolo, Michele

2012-01-01

Residual dipolar couplings (RDCs) have the potential of providing detailed information about the conformational fluctuations of proteins. It is very challenging, however, to extract such information because of the complex relationship between RDCs and protein structures. A promising approach to decode this relationship involves structure-based calculations of the alignment tensors of protein conformations. By implementing this strategy to generate structural restraints in molecular dynamics simulations we show that it is possible to extract effectively the information provided by RDCs about the conformational fluctuations in the native states of proteins. The approach that we present can be used in a wide range of alignment media, including Pf1, charged bicelles and gels. The accuracy of the method is demonstrated by the analysis of the Q factors for RDCs not used as restraints in the calculations, which are significantly lower than those corresponding to existing high-resolution structures and structural ensembles, hence showing that we capture effectively the contributions to RDCs from conformational fluctuations.

Climate technology transfer at the local, national and global levels: analyzing the relationships between multi-level structures

NARCIS (Netherlands)

Tessema Abissa, Fisseha; Tessema Abissa, Fisseha

2014-01-01

This thesis examines the relationships between multi-leveled decision structures for climate technology transfer through an analysis of top-down macro-policy and bottom-up micro-implementation. It examines how international climate technology transfer policy under the UNFCCC filters down to the

Discovery and Structure-Activity Relationship of a Bioactive Fragment of ELABELA that Modulates Vascular and Cardiac Functions

NARCIS (Netherlands)

Murza, Alexandre; Sainsily, Xavier; Coquerel, David; Côté, Jérôme; Marx, Patricia; Besserer-Offroy, Élie; Longpré, Jean-Michel; Lainé, Jean; Reversade, Bruno; Salvail, Dany; Leduc, Richard; Dumaine, Robert; Lesur, Olivier; Auger-Messier, Mannix; Sarret, Philippe; Marsault, Éric

2016-01-01

ELABELA (ELA) was recently discovered as a novel endogenous ligand of the apelin receptor (APJ), a G protein-coupled receptor. ELA signaling was demonstrated to be crucial for normal heart and vasculature development during embryogenesis. We delineate here ELA's structure- activity relationships and

Use of Random and Site-Directed Mutagenesis to Probe Protein Structure-Function Relationships: Applied Techniques in the Study of Helicobacter pylori.

Science.gov (United States)

Whitmire, Jeannette M; Merrell, D Scott

2017-01-01

Mutagenesis is a valuable tool to examine the structure-function relationships of bacterial proteins. As such, a wide variety of mutagenesis techniques and strategies have been developed. This chapter details a selection of random mutagenesis methods and site-directed mutagenesis procedures that can be applied to an array of bacterial species. Additionally, the direct application of the techniques to study the Helicobacter pylori Ferric Uptake Regulator (Fur) protein is described. The varied approaches illustrated herein allow the robust investigation of the structural-functional relationships within a protein of interest.

Pengaruh Customer Relationship Management Terhadap Loyalitas Pelanggan Starbucks Di Surabaya

OpenAIRE

Chandra, Felicia; Wibisono, Benny; Andreani, Fransisca

2017-01-01

: The study is to find the influence of Customer Relationship Management (CRM)on customer loyalty of Starbucks Coffee Surabaya. CRM variables include financial benefits,social benefits and structural ties. Multiple linear regression is used with 150 respondentsusing purposive sampling. The results show that financial benefits and structural ties havepositive and significant influences on customer loyalty; whereas, social benefits has positivebut insignificant influence on customer loyalty. Th...

Faculty research productivity and organizational structure in schools of nursing.

Science.gov (United States)

Kohlenberg, E M

1992-01-01

The purpose of this study was to identify the relationship between faculty research productivity and organizational structure in schools of nursing. The need for nursing research has been widely recognized by members of the nursing profession, yet comparatively few engage in conducting research. Although contextual variables have been investigated that facilitate or inhibit nursing research, the relationship between organizational structure and nursing research productivity has not been examined. This problem was examined within the context of the Entrepreneurial Theory of Formal Organizations. A survey methodology was used for data collection. Data on individual faculty research productivity and organizational structure in the school of nursing were obtained through the use of a questionnaire. A random sample of 300 faculty teaching in 60 master's and doctoral nursing schools in the United States was used. The instruments for data collection were Wakefield-Fisher's Adapted Scholarly Productivity Index and Hall's Organizational Inventory. The data were analyzed using Pearson Product-Moment Correlation Coefficients and multiple correlation/regression techniques. The overall relationship between faculty research productivity and organizational structure in schools of nursing was not significant at the .002 level of confidence. Although statistically significant relationships were not identified, scholarly research productivity and its subscale prepublication and research activities tended to vary positively with procedural specifications in a highly bureaucratic organizational structure. Further research may focus on identification of structural variables that support highly productive nurse researchers.

Statistical significance of theoretical predictions: A new dimension in nuclear structure theories (I)

International Nuclear Information System (INIS)

DUDEK, J; SZPAK, B; FORNAL, B; PORQUET, M-G

2011-01-01

In this and the follow-up article we briefly discuss what we believe represents one of the most serious problems in contemporary nuclear structure: the question of statistical significance of parametrizations of nuclear microscopic Hamiltonians and the implied predictive power of the underlying theories. In the present Part I, we introduce the main lines of reasoning of the so-called Inverse Problem Theory, an important sub-field in the contemporary Applied Mathematics, here illustrated on the example of the Nuclear Mean-Field Approach.

Quantitative structure-activity relationship (QSAR) for insecticides: development of predictive in vivo insecticide activity models.

Science.gov (United States)

Naik, P K; Singh, T; Singh, H

2009-07-01

Quantitative structure-activity relationship (QSAR) analyses were performed independently on data sets belonging to two groups of insecticides, namely the organophosphates and carbamates. Several types of descriptors including topological, spatial, thermodynamic, information content, lead likeness and E-state indices were used to derive quantitative relationships between insecticide activities and structural properties of chemicals. A systematic search approach based on missing value, zero value, simple correlation and multi-collinearity tests as well as the use of a genetic algorithm allowed the optimal selection of the descriptors used to generate the models. The QSAR models developed for both organophosphate and carbamate groups revealed good predictability with r(2) values of 0.949 and 0.838 as well as [image omitted] values of 0.890 and 0.765, respectively. In addition, a linear correlation was observed between the predicted and experimental LD(50) values for the test set data with r(2) of 0.871 and 0.788 for both the organophosphate and carbamate groups, indicating that the prediction accuracy of the QSAR models was acceptable. The models were also tested successfully from external validation criteria. QSAR models developed in this study should help further design of novel potent insecticides.

The prognostic significance and relationship with body composition of CCR7-positive cells in colorectal cancer.

Science.gov (United States)

Malietzis, George; Lee, Gui Han; Bernardo, David; Blakemore, Alexandra I F; Knight, Stella C; Moorghen, Morgan; Al-Hassi, Hafid O; Jenkins, John T

2015-07-01

The host local immune response (LIR) to cancer is a determinant of cancer outcome. Regulation of this local response is largely achieved through chemokine synthesis from the tumor microenvironment such as C-Chemokine-Receptor-7 (CCR7). We examined the LIR measured as CCR7 expression, in colorectal cancers (CRC) and explored relationships with body composition (BC) and survival. A study of paraffin-embedded tissue specimens was carried out in 116 patients with non-metastatic CRC. CCR7 expression was determined by immunohistochemistry. Analysis of computer tomography scans was used to calculate BC parameters. Survival analyses and multivariate regression models were used. High CCR7(+) cell density within the tumor stroma and at the margin was significantly associated with increased age, the presence of lymphovascular invasion, higher tumor stage, lymph node metastasis, high Klintrup-Makinen immune score, and myosteatosis. High CCR7(+) cell density in the tumor margin was significantly associated with shorter disease-free (DFS) and overall survival (OS) (P < 0.001). This was also significantly associated with shorter survival in multivariate analysis (HR = 8.87; 95%CI [2.51-31.3]; P < 0.01 for OS and HR = 4.72; 95%CI (1.24-12.9); P = 0.02 for DFS). Our results suggest that a specific immune microenvironment may be associated with altered host's BC and tumor behavior, and that CCR7 may serve as a novel prognostic biomarker. © 2015 Wiley Periodicals, Inc.

The relationship between cerebral infarction on MR and angiographic findings in moyamoya disease: significance of the posterior circulation

Energy Technology Data Exchange (ETDEWEB)

Lee, Eun Ja; Song, Soon Young [College of Medicine, Kwangdong Univ., Koyang (Korea, Republic of); Yu, Won Jong; Jung, So Lyung; Chung, Bong Gak; Kag, Si Won [College of Medicine, The Catholic Univ. of Korea, Seoul (Korea, Republic of); Kim, Man Deuk [College of Medicine, Pochon CHA Univ., Pochon (Korea, Republic of)

2002-06-01

To investigate the relationship between changes in the posterior and anterior circulation, as seen at angiography, and the frequency and extent of cerebral infarction revealed by MR imaging in moyamoya disease. This study involved 34 patients (22 females and 12 males, aged 2-52 years) in whom cerebral angiography revealed the presence of moyamoya disease (bilateral; unilateral= 24:10; total hemispheres=58) and who also underwent brain MR imaging. To evaluate the angiographic findings, we applied each angiographic staging system to the anterior and posterior circulation. Leptomeningeal collateral circulation from the cortical branches of the posterior cerebral artery (PCA) was also assigned one of four grades. At MR imaging, areas of cerebral cortical or subcortical infarction in the hemisphere were divided into six zones. White matter and basal ganglionic infarction, ventricular dilatation, cortical atrophy, and hemorrhagic lesions were also evaluated. To demonstrate the statistical significance of the relationship between the angiographic and the MR findings, both the Mantel-Haenszel chi-square test for trend and the chi-square test were used. The degree of steno-occlusive PCA change correlated significantly with the internal carotid artery (ICA) stage (p<0.0001). As PCA stages advanced, the degree of leptomeningeal collaterals from the PCA decreased significantly (P<0.0001), but ICA stages were not significant (p>0.05). The prevalence of infarction showed significant correlation with the degree of steno-occlusive change in both the ICA and PCA. The degree of cerebral ischemia in moyamoya patients increased proportionally with the severity of PCA stenosis rather than with that of steno-occlusive lesins of the anterior circulation. Infarctions tended to be distributed in the anterior part of the hemisphere at PCA state I or II, while in more advanced PCA lesions, they were also found posteriorly, especially in the territories of the posterior middle cerebral artery

Non-covalent interaction between dietary stilbenoids and human serum albumin: Structure-affinity relationship, and its influence on the stability, free radical scavenging activity and cell uptake of stilbenoids.

Science.gov (United States)

Cao, Hui; Jia, Xueping; Shi, Jian; Xiao, Jianbo; Chen, Xiaoqing

2016-07-01

Dietary stilbenoids are associated with many benefits for human health, which depend on their bioavailability and bioaccessibility. The stilbenoid-human serum albumin (HSA) interactions are investigated to explore the structure-affinity relationship and influence on the stability, free radical scavenging activity and cell uptake of stilbenoids. The structure-affinity relationship of the stilbenoids-HSA interaction was found as: (1) the methoxylation enhanced the affinity, (2) an additional hydroxyl group increases the affinity and (3) the glycosylation significantly weakened the affinity. HSA obviously masked the free radical scavenging potential of stilbenoids. The stabilities of stilbenoids in different medium were determined as: HSA solution>human plasma>Dulbecco's modified Eagle's medium. It appears that the milk enhanced the cell uptake of stilbenoids with multi-hydroxyl groups and weakened the cell uptake of stilbenoids with methoxyl group on EA.hy 926 endothelial cells. The stilbenoids are hardly absorbed by human umbilical vein endothelial cells in the presence of milk. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantitative structure-activity relationship modeling of the toxicity of organothiophosphate pesticides to Daphnia magna and Cyprinus carpio

NARCIS (Netherlands)

Zvinavashe, E.; Du, T.; Griff, T.; Berg, van den J.H.J.; Soffers, A.E.M.F.; Vervoort, J.J.M.; Murk, A.J.; Rietjens, I.

2009-01-01

Within the REACH regulatory framework in the EU, quantitative structure-activity relationships (QSAR) models are expected to help reduce the number of animals used for experimental testing. The objective of this study was to develop QSAR models to describe the acute toxicity of organothiophosphate

The relationship between species diversity and genetic structure in the rare Picea chihuahuana tree species community, Mexico.

Science.gov (United States)

Simental-Rodríguez, Sergio Leonel; Quiñones-Pérez, Carmen Zulema; Moya, Daniel; Hernández-Tecles, Enrique; López-Sánchez, Carlos Antonio; Wehenkel, Christian

2014-01-01

Species diversity and genetic diversity, the most basic elements of biodiversity, have long been treated as separate topics, although populations evolve within a community context. Recent studies on community genetics and ecology have suggested that genetic diversity is not completely independent of species diversity. The Mexican Picea chihuahuana Martínez is an endemic species listed as "Endangered" on the Red List. Forty populations of Chihuahua spruce have been identified. This species is often associated with tree species of eight genera in gallery forests. This rare Picea chihuahuana tree community covers an area no more than 300 ha and has been subject of several studies involving different topics such as ecology, genetic structure and climate change. The overall aim of these studies was to obtain a dataset for developing management tools to help decision makers implement preservation and conservation strategies. However, this unique forest tree community may also represent an excellent subject for helping us to understand the interplay between ecological and evolutionary processes in determining community structure and dynamics. The AFLP technique and species composition data were used together to test the hypothesis that species diversity is related to the adaptive genetic structure of some dominant tree species (Picea chihuahuana, Pinus strobiformis, Pseudotsuga menziesii and Populus tremuloides) of the Picea chihuahuana tree community at fourteen locations. The Hill numbers were used as a diversity measure. The results revealed a significant correlation between tree species diversity and genetic structure in Populus tremuloides. Because the relationship between the two levels of diversity was found to be positive for the putative adaptive AFLP detected, genetic and species structures of the tree community were possibly simultaneously adapted to a combination of ecological or environmental factors. The present findings indicate that interactions between

Structure activity relationship study of curcumin analogues toward the amyloid-beta aggregation inhibitor.

Science.gov (United States)

Endo, Hitoshi; Nikaido, Yuri; Nakadate, Mamiko; Ise, Satomi; Konno, Hiroyuki

2014-12-15

Inhibition of the amyloid β aggregation process could possibly prevent the onset of Alzheimer's disease. In this article, we report a structure-activity relationship study of curcumin analogues for anti amyloid β aggregation activity. Compound 7, the ideal amyloid β aggregation inhibitor in vitro among synthesized curcumin analogues, has not only potent anti amyloid β aggregation effects, but also water solubility more than 160 times that of curcumin. In addition, new approaches to improve water solubility of curcumin-type compounds are proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.

On the relationship between magnetostatic wave energy and dispersion characteristics in ferrite structures

International Nuclear Information System (INIS)

Vashkovsky, Anatolii V; Lock, Edwin H

2011-01-01

The energy and dispersion characteristics of a dipole spin wave in a ferrite-dielectric-metal structure are calculated. An analysis of spin wave dispersion characteristics with extreme points demonstrates how fundamental relationships among the propagation constant, phase and group velocities, Poynting vector, and power flux manifest themselves when the wavenumber changes near these points. A comparison of magnetostatic approximation results with calculations using Maxwell's equations shows the inadequacy of the magnetostatic approximation formulas currently used for calculating the Poynting vector and power flux of dipole spin waves. A correct alternative is proposed. (methodological notes)

A global view of structure-function relationships in the tautomerase superfamily.

Science.gov (United States)

Davidson, Rebecca; Baas, Bert-Jan; Akiva, Eyal; Holliday, Gemma L; Polacco, Benjamin J; LeVieux, Jake A; Pullara, Collin R; Zhang, Yan Jessie; Whitman, Christian P; Babbitt, Patricia C

2018-02-16

The tautomerase superfamily (TSF) consists of more than 11,000 nonredundant sequences present throughout the biosphere. Characterized members have attracted much attention because of the unusual and key catalytic role of an N-terminal proline. These few characterized members catalyze a diverse range of chemical reactions, but the full scale of their chemical capabilities and biological functions remains unknown. To gain new insight into TSF structure-function relationships, we performed a global analysis of similarities across the entire superfamily and computed a sequence similarity network to guide classification into distinct subgroups. Our results indicate that TSF members are found in all domains of life, with most being present in bacteria. The eukaryotic members of the cis -3-chloroacrylic acid dehalogenase subgroup are limited to fungal species, whereas the macrophage migration inhibitory factor subgroup has wide eukaryotic representation (including mammals). Unexpectedly, we found that 346 TSF sequences lack Pro-1, of which 85% are present in the malonate semialdehyde decarboxylase subgroup. The computed network also enabled the identification of similarity paths, namely sequences that link functionally diverse subgroups and exhibit transitional structural features that may help explain reaction divergence. A structure-guided comparison of these linker proteins identified conserved transitions between them, and kinetic analysis paralleled these observations. Phylogenetic reconstruction of the linker set was consistent with these findings. Our results also suggest that contemporary TSF members may have evolved from a short 4-oxalocrotonate tautomerase-like ancestor followed by gene duplication and fusion. Our new linker-guided strategy can be used to enrich the discovery of sequence/structure/function transitions in other enzyme superfamilies. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

The Structural Relationship between Out-of-School Time Enrichment and Black Student Participation in Advanced Science

Science.gov (United States)

Young, Jamaal; Young, Jemimah

2018-01-01

The researchers tested a model of the structural relationship between Black student engagement in out-of-school time (OST) science enrichment and participation in advanced science courses in high school. The participants in the sample were Black students (N = 3,173) who participated in the High School Longitudinal Study of 2009/2012. The student…

Designing a Quantitative Structure-Activity Relationship for the ...

Science.gov (United States)

Toxicokinetic models serve a vital role in risk assessment by bridging the gap between chemical exposure and potentially toxic endpoints. While intrinsic metabolic clearance rates have a strong impact on toxicokinetics, limited data is available for environmentally relevant chemicals including nearly 8000 chemicals tested for in vitro bioactivity in the Tox21 program. To address this gap, a quantitative structure-activity relationship (QSAR) for intrinsic metabolic clearance rate was developed to offer reliable in silico predictions for a diverse array of chemicals. Models were constructed with curated in vitro assay data for both pharmaceutical-like chemicals (ChEMBL database) and environmentally relevant chemicals (ToxCast screening) from human liver microsomes (2176 from ChEMBL) and human hepatocytes (757 from ChEMBL and 332 from ToxCast). Due to variability in the experimental data, a binned approach was utilized to classify metabolic rates. Machine learning algorithms, such as random forest and k-nearest neighbor, were coupled with open source molecular descriptors and fingerprints to provide reasonable estimates of intrinsic metabolic clearance rates. Applicability domains defined the optimal chemical space for predictions, which covered environmental chemicals well. A reduced set of informative descriptors (including relative charge and lipophilicity) and a mixed training set of pharmaceuticals and environmentally relevant chemicals provided the best intr

Self-esteem mediates the effect of the parent-adolescent relationship on depression.

Science.gov (United States)

Hu, Junmin; Ai, Hongshan

2016-06-01

There is a trend of rapid growth in both the level and occurrence of depression when people reach adolescence. The present study aimed to investigate the impact of the parent-adolescent relationship on depression in adolescents, and mainly focused on the confirmation of the mediator role of self-esteem. A total of 364 senior middle school students accomplished the Parent-Adolescent Relationship Scale, Rosenberg Self-Esteem Scale, and Zung Self-Rating Depression Scale. The results suggested that both parent-adolescent relationship and self-esteem were significantly correlated with depression. Structural equation modeling indicated that self-esteem partially mediated the relationship between parent-adolescent relationship and depression. © The Author(s) 2014.

Correlation and Relationship Analisys for Business Risk and Company Assets

Directory of Open Access Journals (Sweden)

Subagyo Ahmad

2017-12-01

Full Text Available Purpose : This study aims to investigate how variable ratios such as capital structure, NPM, ROA, asset structure and business risk on 60 companies listed on the IDX to know the book ending 2016. Research methodology : The method used in this research is descriptive statistic analysis, correlation analysis and multiple regression analysis. Findings : result of research explains that capital structure of 60 food and beverage industry company have significant relation with variable of Net Profit Margin (NPM equal to 0,0658, business risk equal to 0,0401, asset structure equal to 0,0019 and for ROA variable with no relation significant with a value of 0.5929. So that 3 variables that have significant relationship and 1 variable of capital structure with ROA is not significant. Originality : This study can contribute to the existing literature, especially those related to the analysis of the company’s financial ratios. And later the results of this study can be used as an investigation tool about the impact of business risk to the company’s financial analysis of the food and beverage industry.

Psychometric Properties of the Persian Version of the Relationship Assessment Scale among Couples

Directory of Open Access Journals (Sweden)

غلامرضا دهشیری

2016-06-01

Full Text Available This research administrated to evaluate the psychometric properties of the Persian version of Relationship Assessment scale. Therefore, 315 married individuals (199 women and 116 men from Tehran city were volunteered to respond to four scales: the Relationship Assessment, the Kansas Marital Satisfaction, the Oxford Happiness and the Life Satisfaction. Results from exploratory & confirmatory factor analysis showed that factor structure of Relationship Assessment scale was unidimensional. The internal consistency of the scale in the total sample was 0.88. Significant correlations between scores of the Relationship Assessment scale with the scores of the Kansas Marital Satisfaction Scale, the Life Satisfaction Scale and the Oxford Happiness Questionnaire demonstrated good convergent validity of the scale. Also, the results showed that there was no significant gender difference between the mean scores of relationship satisfaction. In conclusion, the Relationship Assessment scale is a valid and reliable tool to measure marital satisfaction in Iran.

Effect of thermal processing on estimated metabolizable protein supply to dairy cattle from camelina seeds: relationship with protein molecular structural changes.

Science.gov (United States)

Peng, Quanhui; Khan, Nazir A; Wang, Zhisheng; Zhang, Xuewei; Yu, Peiqiang

2014-08-20

This study evaluated the effect of thermal processing on the estimated metabolizable protein (MP) supply to dairy cattle from camelina seeds (Camelina sativa L. Crantz) and determined the relationship between heat-induced changes in protein molecular structural characteristics and the MP supply. Seeds from two camelina varieties were sampled in two consecutive years and were either kept raw or were heated in an autoclave (moist heating) or in an air-draft oven (dry heating) at 120 °C for 1 h. The MP supply to dairy cattle was modeled by three commonly used protein evaluation systems. The protein molecular structures were analyzed by Fourier transform/infrared-attenuated total reflectance molecular spectroscopy. The results showed that both the dry and moist heating increased the contents of truly absorbable rumen-undegraded protein (ARUP) and total MP and decreased the degraded protein balance (DPB). However, the moist-heated camelina seeds had a significantly higher (P seeds. The regression equations showed that intensities of the protein molecular structural bands can be used to estimate the contents of ARUP, MP, and DPB with high accuracy (R(2) > 0.70). These results show that protein molecular structural characteristics can be used to rapidly assess the MP supply to dairy cattle from raw and heat-treated camelina seeds.

Constrained relationship agency as the risk factor for intimate ...

African Journals Online (AJOL)

We used structural equation modelling to identify and measure constrained relationship agency (CRA) as a latent variable, and then tested the hypothesis that CRA plays a significant role in the pathway between IPV and transactional sex. After controlling for CRA, receiving more material goods from a sexual partner was ...

The significance of structural power in Strategic Environmental Assessment

International Nuclear Information System (INIS)

Hansen, Anne Merrild; Kørnøv, Lone; Cashmore, Matthew; Richardson, Tim

2013-01-01

This article presents a study of how power dynamics enables and constrains the influence of actors upon decision-making and Strategic Environmental Assessment (SEA). Based on structuration theory, a model for studying power dynamics in strategic decision-making processes is developed. The model is used to map and analyse key decision arenas in the decision process of aluminium production in Greenland. The analysis shows that communication lines are an important resource through which actors exercise power and influence decision-making on the location of the aluminium production. The SEA process involved not only reproduction of formal communication and decision competence but also production of alternative informal communication structures in which the SEA had capability to influence. It is concluded, that actors influence strategic decision making, and attention needs to be on not only the formal interactions between SEA process and strategic decision-making process but also on informal interaction and communication between actors as the informal structures, which can be crucial to the outcome of the decision-making process. This article is meant as a supplement to the understanding of power dynamics influence in IA processes and as a contribution to the IA research field with a method to analyse power dynamics in strategic decision-making processes. The article also brings reflections of strengths and weaknesses of using the structuration theory as an approach to power analysis. - Highlights: ► Informal interaction influenced process despite the presence of formalised rules. ► Interdependence of actors influenced SEA effectiveness. ► SEA practitioners successfully exercised power to influence decision-making. ► Power dynamics are properties of actors' interactions in decision-making. ► Power structures can be enabling and not solely limiting.

Boiling points of halogenated aliphatic compounds: a quantitative structure-property relationship for prediction and validation.

Science.gov (United States)

Oberg, Tomas

2004-01-01

Halogenated aliphatic compounds have many technical uses, but substances within this group are also ubiquitous environmental pollutants that can affect the ozone layer and contribute to global warming. The establishment of quantitative structure-property relationships is of interest not only to fill in gaps in the available database but also to validate experimental data already acquired. The three-dimensional structures of 240 compounds were modeled with molecular mechanics prior to the generation of empirical descriptors. Two bilinear projection methods, principal component analysis (PCA) and partial-least-squares regression (PLSR), were used to identify outliers. PLSR was subsequently used to build a multivariate calibration model by extracting the latent variables that describe most of the covariation between the molecular structure and the boiling point. Boiling points were also estimated with an extension of the group contribution method of Stein and Brown.

The impact of HMO penetration on the relationship between nurse staffing and quality.

Science.gov (United States)

Mark, Barbara A; Harless, David W; McCue, Michael

2005-07-01

While there are a number of studies examining the relationship between nurse staffing and quality, none has examined structural differences in the relationship between nurse staffing and quality contingent upon the level of managed care penetration. We used administrative data, and a dynamic panel data model to examine this relationship in a panel of 422 acute care hospitals from 1990 to 1995. We found that there were significant differences in the relationship between nurse staffing and both mortality and length of stay depending upon the level of HMO penetration in the hospital's market.

Parental and relationship representations and experiences of depression in college students.

Science.gov (United States)

Sadeh, A; Rubin, S S; Berman, E

1993-02-01

Young adults' descriptions of their parents and their relationships with their parents were used to reexamine the relations between object representation and depressive experience. One hundred eight students completed (a) four open-ended descriptions, including two written descriptions of the parents (mother and father, separately), and two written descriptions of the relationships with the parents; and (b) the Depressive Experience Questionnaire. Each of the four open-ended descriptions was rated on seven scales. Factor analysis yielded four distinct factors from the 28 dimensions of the descriptions. These factors were related to: (a) the degree of elaboration and investment, (b) the structural level of the descriptions, (c) the affective tone of the description of the father, and (d) the affective tone of the description of the mother. Significant differences and interactions were found regarding the interplay between the specific significant other represented (father or mother) and the specific framework of representation (parent description or relationship description). Measures derived from parents' and relationship descriptions significantly predicted depressive experiences of self-criticism and dependency. The results indicate the advantages of a joint exploration of the representation of distinct significant others (mother and father) and the use of two modes of relatedness (describe parent and describe relationship with parent) in the process of personality assessment.

An overview of structure-activity relationship studies of curcumin analogs as antioxidant and anti-inflammatory agents.

Science.gov (United States)

Arshad, Laiba; Haque, Md Areeful; Abbas Bukhari, Syed Nasir; Jantan, Ibrahim

2017-04-01

Curcumin, extracted mainly from Curcuma longa rhizomes, has been reported to possess potent anti-inflammatory and anti-oxidant activities. Although safe at higher doses and exhibiting multiple biological activities, curcumin still has the problem of poor bioavailability which has been an attractive area of research over the last few years. A number of efforts have been made by modifying structural features of curcumin. This review highlights the structurally modified and more stable newly synthesized curcumin analogs that have been screened against antioxidant and anti-inflammatory activities. Also the structure-activity relationship to gain insight into future guidelines for scheming new compounds has been discussed, and further these analogs being more stable may serve as promising agents for use in different pathological conditions.

Significance of fluid-structure interaction phenomena for containment response to ex-vessel steam explosions

Energy Technology Data Exchange (ETDEWEB)

Almstroem, H.; Sundel, T. [National Defence Research Establishment, Stockholm (Sweden); Frid, W.; Engelbrektson, A.

1998-01-01

When studying the structural response of a containment building to ex-vessel steam explosion loads, a two-step procedure is often used. In the first step of this procedure the structures are treated as rigid and the pressure-time history generated by the explosion at the rigid wall is calculated. In the second step the calculated pressure is applied to the structures. The obvious weakness of the two-step procedure is that it does not correspond to the real dynamic behaviour of the fluid-structure system. The purpose of this paper is to identify and evaluate the relevant fluid-structure interaction phenomena. This is achieved through direct treatment of the explosion process and the structural response. The predictions of a direct and two-step treatment are compared for a BWR Mark II containment design, consisting of two concentric walls interacting with water masses in the central and annular pools. It is shown that the two-step approach leads to unrealistic energy transfer in the containment system studied, and to significant overestimation of the deflection of the containment wall. As regards the pedestal wall, the direct method analysis shows that the flexibility of this wall affects the pressure-time history considerably. Three load types have been identified for this wall namely shock load, water blow as a result of water cavitation, and hydrodynamic load. Reloading impulse due to cavitation phenomena plays an important role as it amounts to about 40% of the total impulse load. Investigation of the generality of the cavitation phenomena in the context of ex-vessel steam explosion loads was outside the scope of this work. (author)

Significance of fluid-structure interaction phenomena for containment response to ex-vessel steam explosions

Energy Technology Data Exchange (ETDEWEB)

Almstroem, H.; Sundel, T. (Nat. Defence Res. Establ., Tumba (Sweden)); Frid, W. (Swedish Nuclear Power Inspectorate, SE-10658, Stockholm (Sweden)); Engelbrektson, A. (VBB/SWECO, Box 34044, SE-10026, Stockholm (Sweden))

1999-05-01

When studying the structural response of a containment building to ex-vessel steam explosion loads, a two-step procedure is often used. In the first step of this procedure the structures are treated as rigid and the pressure-time history generated by the explosion, at the rigid wall, is calculated. In the second step the calculated pressure is applied to the structures. The obvious weakness of the two-step procedure is that it does not correspond to the real dynamic behaviour of the fluid-structure system. The purpose of this paper is to identify and evaluate the relevant fluid-structure interaction phenomena. This is achieved through direct treatment of the explosion process and the structural response. The predictions of a direct and two-step treatment are compared for a BWR Mark II containment design, consisting of two concentric walls interacting with water masses in the central and annular pools. It is shown that the two-step approach leads to unrealistic energy transfer in the containment system studied and to significant overestimation of the deflection of the containment wall. As regards the pedestal wall, the direct method analysis shows that the flexibility of this wall affects the pressure-time history considerably. Three load types have been identified for this wall namely shock load, water blow as a result of water cavitation, and hydrodynamic load. Reloading impulse due to cavitation phenomena plays an important role as it amounts to [approx]40% of the total impulse load. Investigation of the generality of the cavitation phenomena in the context of ex-vessel steam explosion loads was outside the scope of this work. (orig.) 5 refs.

Significance of fluid-structure interaction phenomena for containment response to ex-vessel steam explosions

International Nuclear Information System (INIS)

Almstroem, H.; Sundel, T.; Frid, W.; Engelbrektson, A.

1999-01-01

When studying the structural response of a containment building to ex-vessel steam explosion loads, a two-step procedure is often used. In the first step of this procedure the structures are treated as rigid and the pressure-time history generated by the explosion, at the rigid wall, is calculated. In the second step the calculated pressure is applied to the structures. The obvious weakness of the two-step procedure is that it does not correspond to the real dynamic behaviour of the fluid-structure system. The purpose of this paper is to identify and evaluate the relevant fluid-structure interaction phenomena. This is achieved through direct treatment of the explosion process and the structural response. The predictions of a direct and two-step treatment are compared for a BWR Mark II containment design, consisting of two concentric walls interacting with water masses in the central and annular pools. It is shown that the two-step approach leads to unrealistic energy transfer in the containment system studied and to significant overestimation of the deflection of the containment wall. As regards the pedestal wall, the direct method analysis shows that the flexibility of this wall affects the pressure-time history considerably. Three load types have been identified for this wall namely shock load, water blow as a result of water cavitation, and hydrodynamic load. Reloading impulse due to cavitation phenomena plays an important role as it amounts to ∼40% of the total impulse load. Investigation of the generality of the cavitation phenomena in the context of ex-vessel steam explosion loads was outside the scope of this work. (orig.)

Significance tests for functional data with complex dependence structure.

Science.gov (United States)

Staicu, Ana-Maria; Lahiri, Soumen N; Carroll, Raymond J

2015-01-01

We propose an L 2 -norm based global testing procedure for the null hypothesis that multiple group mean functions are equal, for functional data with complex dependence structure. Specifically, we consider the setting of functional data with a multilevel structure of the form groups-clusters or subjects-units, where the unit-level profiles are spatially correlated within the cluster, and the cluster-level data are independent. Orthogonal series expansions are used to approximate the group mean functions and the test statistic is estimated using the basis coefficients. The asymptotic null distribution of the test statistic is developed, under mild regularity conditions. To our knowledge this is the first work that studies hypothesis testing, when data have such complex multilevel functional and spatial structure. Two small-sample alternatives, including a novel block bootstrap for functional data, are proposed, and their performance is examined in simulation studies. The paper concludes with an illustration of a motivating experiment.

Significance tests for functional data with complex dependence structure

KAUST Repository

Staicu, Ana-Maria

2015-01-01

We propose an L (2)-norm based global testing procedure for the null hypothesis that multiple group mean functions are equal, for functional data with complex dependence structure. Specifically, we consider the setting of functional data with a multilevel structure of the form groups-clusters or subjects-units, where the unit-level profiles are spatially correlated within the cluster, and the cluster-level data are independent. Orthogonal series expansions are used to approximate the group mean functions and the test statistic is estimated using the basis coefficients. The asymptotic null distribution of the test statistic is developed, under mild regularity conditions. To our knowledge this is the first work that studies hypothesis testing, when data have such complex multilevel functional and spatial structure. Two small-sample alternatives, including a novel block bootstrap for functional data, are proposed, and their performance is examined in simulation studies. The paper concludes with an illustration of a motivating experiment.

Quantitative Structure activity relationship and risk analysis of some pesticides in the cattle milk

OpenAIRE

Faqir Muhammad*, Ijaz Javed, Masood Akhtar1, Zia-ur-Rahman, Mian Muhammad Awais1, Muhammad Kashif Saleemi2 and Muhammad Irfan Anwar3

2012-01-01

Milk of cattle was collected from various localities of Faisalabad, Pakistan. Pesticides concentration was determined by HPLC using solid phase microextraction. The residue analysis revealed that about 40% milk samples were contaminated with pesticides. The mean±SE levels (ppm) of cyhalothrin, endosulfan, chlorpyrifos and cypermethrin were 0.38±0.02, 0.26±0.02, 0.072±0.01 and 0.085±0.02, respectively. Quantitative structure activity relationship (QSAR) models were used to predict the residues...

The brief family relationship scale: a brief measure of the relationship dimension in family functioning.

Science.gov (United States)

Fok, Carlotta Ching Ting; Allen, James; Henry, David

2014-02-01

The Relationship dimension of the Family Environment Scale, which consists of the Cohesion, Expressiveness, and Conflict subscales, measures a person's perception of the quality of his or her family relationship functioning. This study investigates an adaptation of the Relationship dimension of the Family Environment Scale for Alaska Native youth. The authors tested the adapted measure, the Brief Family Relationship Scale, for psychometric properties and internal structure with 284 12- to 18-year-old predominately Yup'ik Eskimo Alaska Native adolescents from rural, remote communities. This non-Western cultural group is hypothesized to display higher levels of collectivism traditionally organized around an extended kinship family structure. Results demonstrate a subset of the adapted items function satisfactorily, a three-response alternative format provided meaningful information, and the subscale's underlying structure is best described through three distinct first-order factors, organized under one higher order factor. Convergent and discriminant validity of the Brief Family Relationship Scale was assessed through correlational analysis.

Evolutionary relationship and structural characterization of the EPF/EPFL gene family.

Science.gov (United States)

Takata, Naoki; Yokota, Kiyonobu; Ohki, Shinya; Mori, Masashi; Taniguchi, Toru; Kurita, Manabu

2013-01-01

EPF1-EPF2 and EPFL9/Stomagen act antagonistically in regulating leaf stomatal density. The aim of this study was to elucidate the evolutionary functional divergence of EPF/EPFL family genes. Phylogenetic analyses showed that AtEPFL9/Stomagen-like genes are conserved only in vascular plants and are closely related to AtEPF1/EPF2-like genes. Modeling showed that EPF/EPFL peptides share a common 3D structure that is constituted of a scaffold and loop. Molecular dynamics simulation suggested that AtEPF1/EPF2-like peptides form an additional disulfide bond in their loop regions and show greater flexibility in these regions than AtEPFL9/Stomagen-like peptides. This study uncovered the evolutionary relationship and the conformational divergence of proteins encoded by the EPF/EPFL family genes.

The relationship between the applied torque and stresses in post-tension structures

International Nuclear Information System (INIS)

Liew, F.K.; Hamdan, S.; Osman, M.S.

2008-01-01

This paper presents the nondestructive testing (NDT) method to determine the resultant stresses in mild steel bar usually employed in structures. The technique utilized ultrasonic pulse-echo that determined the wave velocity change due to torque applied between bolt and nut. Mild steel bar with nominal diameter of 19 and 25mm were used. The specimen was loaded by means of a torque wrench that gave the required amount of moment (∼300Nm). This was carefully achieved manually. In order to measure the strain, strain gauges were employed. The direct strain gauge method gives the strain values. This strain is used to calculate the stress due to the applied load. The experiment had been carried out in a control environment with constant temperature. The relationship between torque-velocity, torque-strain and stress-strain is obtained and compared. The test results indicate that ultrasonic wave velocity decrease with the applied torque. This is due to degradation or loss of strength of the material. The potential of this NDT method to obtain structure quality and strength determination is discussed. (author)

The relationship between the applied torque and stresses in post-tension structures

Energy Technology Data Exchange (ETDEWEB)

Liew, F.K.; Hamdan, S.; Osman, M.S. [Univ. Malaysia Sarawak, Faculty of Engineering, Kota Samarahan, Sarawak (Malaysia)

2008-09-15

This paper presents the nondestructive testing (NDT) method to determine the resultant stresses in mild steel bar usually employed in structures. The technique utilized ultrasonic pulse-echo that determined the wave velocity change due to torque applied between bolt and nut. Mild steel bar with nominal diameter of 19 and 25mm were used. The specimen was loaded by means of a torque wrench that gave the required amount of moment (∼300Nm). This was carefully achieved manually. In order to measure the strain, strain gauges were employed. The direct strain gauge method gives the strain values. This strain is used to calculate the stress due to the applied load. The experiment had been carried out in a control environment with constant temperature. The relationship between torque-velocity, torque-strain and stress-strain is obtained and compared. The test results indicate that ultrasonic wave velocity decrease with the applied torque. This is due to degradation or loss of strength of the material. The potential of this NDT method to obtain structure quality and strength determination is discussed. (author)

The incidence of significant relationships between selected parameters of feet and parameters of trunk in children aged 4, 5 and 6 years

Directory of Open Access Journals (Sweden)

Mirosław Mrozkowiak

2018-02-01

2. Foot parameters revealed the most frequent significant relationship with trunk parameters in the sagittal and frontal planes. Trunk parameters with which foot parameters correlated most often included: asymmetry in the height of both scapulas with the right scapula up, inclination of thoracolumbar region and asymmetry in the height of waist triangles with the right triangle up.

Structure-activity relationships of lanostane-type triterpenoids from Ganoderma lingzhi as α-glucosidase inhibitors.

Science.gov (United States)

Fatmawati, Sri; Kondo, Ryuichiro; Shimizu, Kuniyoshi

2013-11-01

A series of lanostane-type triterpenoids, identified as ganoderma alcohols and ganoderma acids, were isolated from the fruiting body of Ganoderma lingzhi. Some of these compounds were confirmed as active inhibitors of the in vitro human recombinant aldose reductase. This paper aims to explain the structural requirement for α-glucosidase inhibition. Our structure-activity studies of ganoderma alcohols showed that the OH substituent at C-3 and the double-bond moiety at C-24 and C-25 are necessary to increase α-glucosidase inhibitory activity. The structure-activity relationships of ganoderma acids revealed that the OH substituent at C-11 is an important feature and that the carboxylic group in the side chain is essential for the recognition of α-glucosidase inhibitory activity. Moreover, the double-bond moiety at C-20 and C-22 in the side chain and the OH substituent at C-3 of ganoderma acids improve α-glucosidase inhibitory activity. These results provide an approach with which to consider the structural requirements of lanostane-type triterpenoids from G. lingzhi. An understanding of these requirements is considered necessary in order to improve a new type of α-glucosidase inhibitor. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Relationship Between Structural Game Characteristics and Gambling Behavior: A Population-Level Study.

Science.gov (United States)

Leino, Tony; Torsheim, Torbjørn; Blaszczynski, Alex; Griffiths, Mark; Mentzoni, Rune; Pallesen, Ståle; Molde, Helge

2015-12-01

The aim of this study was to examine the relationship between the structural characteristics and gambling behavior among video lottery terminal (VLT) gamblers. The study was ecological valid, because the data consisted of actual gambling behavior registered in the participants natural gambling environment without intrusion by researchers. Online behavioral tracking data from Multix, an eight game video lottery terminal, were supplied by Norsk-Tipping (the state owned gambling company in Norway). The sample comprised the entire population of Multix gamblers (N = 31,109) who had gambled in January 2010. The individual number of bets made across games was defined as the dependent variable, reward characteristics of a game (i.e., payback percentage, hit frequency, size of winnings and size of jackpot) and bet characteristics of a game (i.e., range of betting options and availability of advanced betting options) served as the independent variables. Control variables were age and gender. Two separate cross-classified multilevel random intercepts models were used to analyze the relationship between bets made, reward characteristics and bet characteristics, where the number of bets was nested within both individuals and within games. The results show that the number of bets is positively associated with payback percentage, hit frequency, being female and age, and negatively associated with size of wins and range of available betting options. In summary, the results show that the reward characteristics and betting options explained 27% and 15% of the variance in the number of bets made, respectively. It is concluded that structural game characteristics affect gambling behavior. Implications of responsible gambling are discussed.

Individual-based ant-plant networks: diurnal-nocturnal structure and species-area relationship.

Directory of Open Access Journals (Sweden)

Wesley Dáttilo

Full Text Available Despite the importance and increasing knowledge of ecological networks, sampling effort and intrapopulation variation has been widely overlooked. Using continuous daily sampling of ants visiting three plant species in the Brazilian Neotropical savanna, we evaluated for the first time the topological structure over 24 h and species-area relationships (based on the number of extrafloral nectaries available in individual-based ant-plant networks. We observed that diurnal and nocturnal ant-plant networks exhibited the same pattern of interactions: a nested and non-modular pattern and an average level of network specialization. Despite the high similarity in the ants' composition between the two collection periods, ant species found in the central core of highly interacting species totally changed between diurnal and nocturnal sampling for all plant species. In other words, this "night-turnover" suggests that the ecological dynamics of these ant-plant interactions can be temporally partitioned (day and night at a small spatial scale. Thus, it is possible that in some cases processes shaping mutualistic networks formed by protective ants and plants may be underestimated by diurnal sampling alone. Moreover, we did not observe any effect of the number of extrafloral nectaries on ant richness and their foraging on such plants in any of the studied ant-plant networks. We hypothesize that competitively superior ants could monopolize individual plants and allow the coexistence of only a few other ant species, however, other alternative hypotheses are also discussed. Thus, sampling period and species-area relationship produces basic information that increases our confidence in how individual-based ant-plant networks are structured, and the need to consider nocturnal records in ant-plant network sampling design so as to decrease inappropriate inferences.

Synthesis and Structure-Activity Relationships of Novel Amino/Nitro Substituted 3-Arylcoumarins as Antibacterial Agents

Directory of Open Access Journals (Sweden)

Ysabel Santos

2013-01-01

Full Text Available A new series of amino/nitro-substituted 3-arylcoumarins were synthesized and their antibacterial activity against clinical isolates of Staphylococcus aureus (Gram-positive and Escherichia coli (Gram-negative was evaluated. Some of these molecules exhibited antibacterial activity against S. aureus comparable to the standards used (oxolinic acid and ampicillin. The preliminary structure-activity relationship (SAR study showed that the antibacterial activity against S. aureus depends on the position of the 3-arylcoumarin substitution pattern. With the aim of finding the structural features for the antibacterial activity and selectivity, in the present manuscript different positions of nitro, methyl, methoxy, amino and bromo substituents on the 3-arylcoumarin scaffold were reported.

Sustainable Corporate Social Media Marketing Based on Message Structural Features: Firm Size Plays a Significant Role as a Moderator

Directory of Open Access Journals (Sweden)

Moon Young Kang

2018-04-01

Full Text Available Social media has been receiving attention as a cost-effective tool to build corporate brand image and to enrich customer relationships. This phenomenon calls for more attention to developing a model that measures the impact of structural features, used in corporate social media messages. Based on communication science, this study proposes a model to measure the impact of three essential message structural features (interactivity, formality, and immediacy in corporate social media on customers’ purchase intentions, mediated by brand attitude and corporate trust. Especially, social media platforms are believed to provide a good marketing platform for small and medium enterprises (SMEs by providing access to huge audiences at a very low cost. The findings from this study based on a structural equation model suggest that brand attitude and corporate trust have larger impacts on purchase intention for SMEs than large firms. This implies that SMEs with little to no presence in the market should pay more attention to building corporate trust and brand attitude for their sustainable growth.

Data-driven multi-scale multi-physics models to derive process-structure-property relationships for additive manufacturing

Science.gov (United States)

Yan, Wentao; Lin, Stephen; Kafka, Orion L.; Lian, Yanping; Yu, Cheng; Liu, Zeliang; Yan, Jinhui; Wolff, Sarah; Wu, Hao; Ndip-Agbor, Ebot; Mozaffar, Mojtaba; Ehmann, Kornel; Cao, Jian; Wagner, Gregory J.; Liu, Wing Kam

2018-01-01

Additive manufacturing (AM) possesses appealing potential for manipulating material compositions, structures and properties in end-use products with arbitrary shapes without the need for specialized tooling. Since the physical process is difficult to experimentally measure, numerical modeling is a powerful tool to understand the underlying physical mechanisms. This paper presents our latest work in this regard based on comprehensive material modeling of process-structure-property relationships for AM materials. The numerous influencing factors that emerge from the AM process motivate the need for novel rapid design and optimization approaches. For this, we propose data-mining as an effective solution. Such methods—used in the process-structure, structure-properties and the design phase that connects them—would allow for a design loop for AM processing and materials. We hope this article will provide a road map to enable AM fundamental understanding for the monitoring and advanced diagnostics of AM processing.

Data-driven multi-scale multi-physics models to derive process-structure-property relationships for additive manufacturing

Science.gov (United States)

Yan, Wentao; Lin, Stephen; Kafka, Orion L.; Lian, Yanping; Yu, Cheng; Liu, Zeliang; Yan, Jinhui; Wolff, Sarah; Wu, Hao; Ndip-Agbor, Ebot; Mozaffar, Mojtaba; Ehmann, Kornel; Cao, Jian; Wagner, Gregory J.; Liu, Wing Kam

2018-05-01

Additive manufacturing (AM) possesses appealing potential for manipulating material compositions, structures and properties in end-use products with arbitrary shapes without the need for specialized tooling. Since the physical process is difficult to experimentally measure, numerical modeling is a powerful tool to understand the underlying physical mechanisms. This paper presents our latest work in this regard based on comprehensive material modeling of process-structure-property relationships for AM materials. The numerous influencing factors that emerge from the AM process motivate the need for novel rapid design and optimization approaches. For this, we propose data-mining as an effective solution. Such methods—used in the process-structure, structure-properties and the design phase that connects them—would allow for a design loop for AM processing and materials. We hope this article will provide a road map to enable AM fundamental understanding for the monitoring and advanced diagnostics of AM processing.

Finescale Structure of the Temperature-Salinity Relationship

National Research Council Canada - National Science Library

Polzin, Kurt L; Ferrari, Raffaele

2005-01-01

The long term goal of this project is to understand the processes that establish the temperature-salinity relationship in the ocean, with emphasis on the interplay between advection at the large scale...

The structural, connectomic and network covariance of the human brain.

Science.gov (United States)

Irimia, Andrei; Van Horn, John D

2013-02-01

Though it is widely appreciated that complex structural, functional and morphological relationships exist between distinct areas of the human cerebral cortex, the extent to which such relationships coincide remains insufficiently appreciated. Here we determine the extent to which correlations between brain regions are modulated by either structural, connectomic or network-theoretic properties using a structural neuroimaging data set of magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) volumes acquired from N=110 healthy human adults. To identify the linear relationships between all available pairs of regions, we use canonical correlation analysis to test whether a statistically significant correlation exists between each pair of cortical parcels as quantified via structural, connectomic or network-theoretic measures. In addition to this, we investigate (1) how each group of canonical variables (whether structural, connectomic or network-theoretic) contributes to the overall correlation and, additionally, (2) whether each individual variable makes a significant contribution to the test of the omnibus null hypothesis according to which no correlation between regions exists across subjects. We find that, although region-to-region correlations are extensively modulated by structural and connectomic measures, there are appreciable differences in how these two groups of measures drive inter-regional correlation patterns. Additionally, our results indicate that the network-theoretic properties of the cortex are strong modulators of region-to-region covariance. Our findings are useful for understanding the structural and connectomic relationship between various parts of the brain, and can inform theoretical and computational models of cortical information processing. Published by Elsevier Inc.

Exploring the relationships among attachment, emotional intelligence and communication.

Science.gov (United States)

Cherry, M Gemma; Fletcher, Ian; O'Sullivan, Helen

2013-03-01

Attachment style has been shown to influence both emotional intelligence (EI) and the clinical communication of medical students and doctors. No research has assessed the relationships among attachment, EI and clinical communication in medical students. This study was conducted to evaluate the effect of EI on the relationship between medical students' attachment style and clinical communication. Medical students were invited to complete measures of attachment (using the Experiences in Close Relationships-Short Form [ECR-SF], a 12-item measure that provides attachment avoidance and attachment anxiety dimensional scores) and EI (using the Mayer-Salovey-Caruso Emotional Intelligence Test [MSCEIT], a 141-item measure of the perception, use, understanding and management of emotions) at the end of Year 1, prior to a summative objective structured clinical examination (OSCE). Clinical communication was assessed using OSCE scores. Structural equation modelling (SEM) was used to analyse a hypothetical model of the relationships among attachment style, EI and clinical communication. A total of 200 of 358 (55.9%) students participated. Attachment avoidance was significantly negatively correlated with total EI scores (r=-0.28, pcommunication. © Blackwell Publishing Ltd 2013.

Relationship between Chemical Structure and Antimicrobial Activities of Isothiocyanates from Cruciferous Vegetables against Oral Pathogens.

Science.gov (United States)

Ko, Mi-Ok; Kim, Mi-Bo; Lim, Sang-Bin

2016-12-28

We evaluated the potentials of 10 isothiocyanates (ITCs) from cruciferous vegetables and radish root hydrolysate for inhibiting the growth of oral pathogens, with an emphasis on assessing any structure-function relationship. Structural differences in ITCs impacted their antimicrobial activities against oral pathogens differently. The indolyl ITC (indol-3-carbinol) was the most potent inhibitor of the growth of oral pathogens, followed by aromatic ITCs (benzyl ITC (BITC) and phenylethyl ITC (PEITC)) and aliphatic ITCs (erucin, iberin, and sulforaphene). Sulforaphene, which is similar in structure, but has one double bond, showed higher antimicrobial activity than sulforaphane. Erucin, which has a thiol group, showed higher antimicrobial activity than sulforaphane, which has a sulfinyl group. BITC and iberin with a short chain exhibited higher antimicrobial potential than PEITC and sulforaphane with a longer chain, respectively. ITCs have strong antimicrobial activities and may be useful in the prevention and management of dental caries.

Relationship between obesity and the risk of clinically significant depression: Mendelian randomisation study.

LENUS (Irish Health Repository)

Hung, Chi-Fa

2014-07-01

Obesity has been shown to be associated with depression and it has been suggested that higher body mass index (BMI) increases the risk of depression and other common mental disorders. However, the causal relationship remains unclear and Mendelian randomisation, a form of instrumental variable analysis, has recently been employed to attempt to resolve this issue.

Scientific habits of mind: A reform of structure and relationships

Science.gov (United States)

Mooney, Linda Beth

This research was designed to broaden current elementary science reform efforts by including the voices of our young scientists. Ten high school students who were defined as possessing both coherent science knowledge and scientific habits of mind were selected for the study. Through a three-part series of in-depth, phenomenological interviews, these students revealed early childhood experiences from birth through age ten to which they attributed their development of science knowledge and scientific habits of mind. Educational connoisseurship and criticism provided the framework through which the experiences were analyzed. The research revealed the overwhelming role of scientific habits of mind in the current success of these young scientists. Scientific habits of mind were developed through the structures and relationships in the home. Parents of the participants provided a non-authoritarian, fun, playful, tolerant atmosphere in which messes and experimentation were the norm. Large blocks of uninterrupted, unstructured time and space that "belonged" to the child allowed these children to follow where curiosity led. Frequently, the parent modeled scientific habits of mind. Good discipline in the minds of these families had nothing to do with punishments, rewards, or rules. The parents gave the children responsibilities, "free rein," and their trust, and the children blossomed in that trust and mutual respect. Parents recognized and supported the uniqueness, autonomy, interests, and emotions of the child. Above all, the young scientists valued the time, freedom, patience, and emotional support provided by their parents. For girls, construction toys, hot wheels, sand boxes, and outdoor experiences were particularly important. Art classes, free access to art media, sewing, music, and physical activity facilitated observational skills and spatial relationship development. The girls knew that doing traditionally masculine and feminine activities were acceptable and

CASS Ferrite and Grain Structure Relationship

Energy Technology Data Exchange (ETDEWEB)

Ruud, Clayton O. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meyer, Ryan M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Diaz, Aaron A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Anderson, Michael T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-07-13

This document summarizes the results of research conducted at Pacific Northwest National Laboratory (PNNL) to determine whether, based on experimental measurements, a correlation existed between grain structure in cast austenitic stainless steel (CASS) piping and ferrite content of the casting alloy. The motivation for this research lies in the fact that ultrasonic testing (UT) is strongly influenced by CASS grain structure; knowledge of this grain structure may help improve the ability to interpret UT responses, thereby improving the overall reliability of UT inspections of CASS components.

A multilevel cross-lagged structural equation analysis for reciprocal relationship between social capital and health

OpenAIRE

Sessions, John; Yu, Ge; Fu, Yu; Wall, Matin

2015-01-01

We investigated the reciprocal relationship between individual social capital and perceived mental and physical health in the UK. Using data from the British Household Panel Survey from 1991 to 2008, we fitted cross-lagged structural equation models that include three indicators of social capital vis. social participation, social network, and loneliness. Given that multiple measurement points (level 1) are nested within individuals (level 2), we also applied a multilevel model to allow for re...

Current data regarding the structure-toxicity relationship of boron-containing compounds.

Science.gov (United States)

Farfán-García, E D; Castillo-Mendieta, N T; Ciprés-Flores, F J; Padilla-Martínez, I I; Trujillo-Ferrara, J G; Soriano-Ursúa, M A

2016-09-06

Boron is ubiquitous in nature, being an essential element of diverse cells. As a result, humans have had contact with boron containing compounds (BCCs) for a long time. During the 20th century, BCCs were developed as antiseptics, antibiotics, cosmetics and insecticides. Boric acid was freely used in the nosocomial environment as an antiseptic and sedative salt, leading to the death of patients and an important discovery about its critical toxicology for humans. Since then the many toxicological studies done in relation to BCCs have helped to establish the proper limits of their use. During the last 15 years, there has been a boom of research on the design and use of new, potent and efficient boron containing drugs, finding that the addition of boron to some known drugs increases their affinity and selectivity. This mini-review summarizes two aspects of BCCs: toxicological data found with experimental models, and the scarce but increasing data about the structure-activity relationship for toxicity and therapeutic use. As is the case with boron-free compounds, the biological activity of BCCs is related to their chemical structure. We discuss the use of new technology to discover potent and efficient BCCs for medicinal therapy by avoiding toxic effects. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

[Structure of Relationships Formed by Occupational Health Nurses for Co-operating with Managers to Support Workers with Mental Health Concerns].

Science.gov (United States)

Hatanaka, Junko; Takasaki, Masako; Hatanaka, Michiyo

2018-05-31

Occupational health staff and managers play important roles in supporting workers with mental health concerns and mutual co-operation among them is a necessary element. However, when co-operating with other professionals, several problems arise that often make such co-operation a challenge. Effective mutual actions are needed to promote such co-operation, and relationships must be formed for this purpose. Therefore, in this study, we aimed to clarify how occupational health nurses form relationships for facilitating co-operation with managers to provide support to workers with mental health concerns. Data were collected using semi-structured interviews with 11 occupational health nurses who provide individualized mental health support and who have at least 5 years of experience as occupational health nurses. Analysis of the recorded interviews was performed using a qualitative statistical method (KJ method). Six elements that constitute the formation of relationships were identified. When occupational health nurses form relationships for facilitating co-operation with a manager to provide support to workers, they "form relationships through strategic communication" with them and when co-operation is required, they form a relationship by "acting in a manner that suits the manager," such as his/her character and the situation. To support this relationship, occupational health nurses "provide mental support to the manager" by listening to his/her anxiety or real intention about supporting the subordinate with mental health concerns and provide relief while understanding their burdens during the co-operation. Occupational health nurses even "provide support to the manager in their activities," which assessed the situation at the workplace as the specialist and advised the manager to understand how to concern to the subordinate specifically. In addition, they "indirectly support the manager" which included coordinating with the concerned persons so as to not excessively

Free and Open Source Chemistry Software in Research of Quantitative Structure-Toxicity Relationship of Pesticides

Directory of Open Access Journals (Sweden)

Rastija Vesna

2017-01-01

Full Text Available Pesticides are toxic chemicals aimed for the destroying pest on crops. Numerous data evidence about toxicity of pesticides on aquatic organisms. Since pesticides with similar properties tend to have similar biological activities, toxicity may be predicted from structure. Their structure feature and properties are encoded my means of molecular descriptors. Molecular descriptors can capture quite simple two-dimensional (2D chemical structures to highly complex three-dimensional (3D chemical structures. Quantitative structure-toxicity relationship (QSTR method uses linear regression analyses for correlation toxicity of chemical with their structural feature using molecular descriptors. Molecular descriptors were calculated using open source software PaDEL and in-house built PyMOL plugin (PyDescriptor. PyDescriptor is a new script implemented with the commonly used visualization software PyMOL for calculation of a large and diverse set of easily interpretable molecular descriptors encoding pharmacophoric patterns and atomic fragments. PyDescriptor has several advantages like free and open source, can work on all major platforms (Windows, Linux, MacOS. QSTR method allows prediction of toxicity of pesticides without experimental assay. In the present work, QSTR analysis for toxicity of a dataset of mixtures of 5 classes of pesticides comprising has been performed.

Improving quantitative structure-activity relationship models using Artificial Neural Networks trained with dropout.

Science.gov (United States)

Mendenhall, Jeffrey; Meiler, Jens

2016-02-01

Dropout is an Artificial Neural Network (ANN) training technique that has been shown to improve ANN performance across canonical machine learning (ML) datasets. Quantitative Structure Activity Relationship (QSAR) datasets used to relate chemical structure to biological activity in Ligand-Based Computer-Aided Drug Discovery pose unique challenges for ML techniques, such as heavily biased dataset composition, and relatively large number of descriptors relative to the number of actives. To test the hypothesis that dropout also improves QSAR ANNs, we conduct a benchmark on nine large QSAR datasets. Use of dropout improved both enrichment false positive rate and log-scaled area under the receiver-operating characteristic curve (logAUC) by 22-46 % over conventional ANN implementations. Optimal dropout rates are found to be a function of the signal-to-noise ratio of the descriptor set, and relatively independent of the dataset. Dropout ANNs with 2D and 3D autocorrelation descriptors outperform conventional ANNs as well as optimized fingerprint similarity search methods.

Comparative Analysis of Predictive Models for Liver Toxicity Using ToxCast Assays and Quantitative Structure-Activity Relationships (MCBIOS)

Science.gov (United States)

Comparative Analysis of Predictive Models for Liver Toxicity Using ToxCast Assays and Quantitative Structure-Activity Relationships Jie Liu1,2, Richard Judson1, Matthew T. Martin1, Huixiao Hong3, Imran Shah1 1National Center for Computational Toxicology (NCCT), US EPA, RTP, NC...

Sexual dimorphism of the incidence of significant relationships between selected parameters of feet and characteristics of trunk in adolescents aged 14 – 18 years

Directory of Open Access Journals (Sweden)

Mirosław Mrozkowiak

2018-03-01

Full Text Available Summary Introduction. Symmetry, asymmetry, mutual relationships and concomitance have become a subject of interest of numerous researchers. The analysis of the findings obtained in the own study conducted among adolescents aged 14-18 years revealed an incidental nature and randomness of the distribution of significant correlations in each age and gender range, which made it impossible to show any regularities or dependencies between the measured parameters. Material and method. The examinations carried out in the group of teenagers aged 14 to 18 years recorded 2,343 observations, including 1,148 girls and 1,195 boys, concerning the size of 89 parameters describing trunk and feet. The station for an assessment of selected features using the photogrammetric method consisted of a computer, a card, software, a display monitor, a printer and a projection-reception device with a camera.     Findings 1. The number of feet parameters revealing significant relationships with trunk parameters which differentiated the female gender from the male one was greater; likewise, the features in women revealed a more frequent relationship. Additionally, female sex was differentiated by morphological traits, the abnormal positioning of toes and the longitudinal arch of feet. 2. The number of trunk parameters correlating with foot parameters was observed to be bigger in the female gender than in the male one. The parameters in female subjects showed more relationships and the parameters which differentiated female sex included the frontal plane and the sagittal plane to a lesser extent, whereas male gender was characterized by the sagittal plane.

Quantitative structure-activity relationship modeling on in vitro endocrine effects and metabolic stability involving 26 selected brominated flame retardants

NARCIS (Netherlands)

Harju, M.; Hamers, T.; Kamstra, J.H.; Sonneveld, E.; Boon, J.P.

2007-01-01

In this work, quantitative structure-activity relationships (QSARs) were developed to aid human and environmental risk assessment processes for brominated flame retardants (BFRs). Brominated flame retardants, such as the high-production-volume chemicals polybrominated diphenyl ethers (PBDEs),

Using structural equation modeling to investigate relationships among ecological variables

Science.gov (United States)

Malaeb, Z.A.; Kevin, Summers J.; Pugesek, B.H.

2000-01-01

Structural equation modeling is an advanced multivariate statistical process with which a researcher can construct theoretical concepts, test their measurement reliability, hypothesize and test a theory about their relationships, take into account measurement errors, and consider both direct and indirect effects of variables on one another. Latent variables are theoretical concepts that unite phenomena under a single term, e.g., ecosystem health, environmental condition, and pollution (Bollen, 1989). Latent variables are not measured directly but can be expressed in terms of one or more directly measurable variables called indicators. For some researchers, defining, constructing, and examining the validity of latent variables may be the end task of itself. For others, testing hypothesized relationships of latent variables may be of interest. We analyzed the correlation matrix of eleven environmental variables from the U.S. Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) using methods of structural equation modeling. We hypothesized and tested a conceptual model to characterize the interdependencies between four latent variables-sediment contamination, natural variability, biodiversity, and growth potential. In particular, we were interested in measuring the direct, indirect, and total effects of sediment contamination and natural variability on biodiversity and growth potential. The model fit the data well and accounted for 81% of the variability in biodiversity and 69% of the variability in growth potential. It revealed a positive total effect of natural variability on growth potential that otherwise would have been judged negative had we not considered indirect effects. That is, natural variability had a negative direct effect on growth potential of magnitude -0.3251 and a positive indirect effect mediated through biodiversity of magnitude 0.4509, yielding a net positive total effect of 0

Evolutionary relationship and structural characterization of the EPF/EPFL gene family.

Directory of Open Access Journals (Sweden)

Naoki Takata

Full Text Available EPF1-EPF2 and EPFL9/Stomagen act antagonistically in regulating leaf stomatal density. The aim of this study was to elucidate the evolutionary functional divergence of EPF/EPFL family genes. Phylogenetic analyses showed that AtEPFL9/Stomagen-like genes are conserved only in vascular plants and are closely related to AtEPF1/EPF2-like genes. Modeling showed that EPF/EPFL peptides share a common 3D structure that is constituted of a scaffold and loop. Molecular dynamics simulation suggested that AtEPF1/EPF2-like peptides form an additional disulfide bond in their loop regions and show greater flexibility in these regions than AtEPFL9/Stomagen-like peptides. This study uncovered the evolutionary relationship and the conformational divergence of proteins encoded by the EPF/EPFL family genes.

Empirical study with structural break on the relationship between financial development and economic growth of Jiangxi province

Directory of Open Access Journals (Sweden)

Jiang Xinxi

2016-01-01

Full Text Available The empirical study over the period 1978-2011 found that the relationship between real per capita GDP and financial interrelation ratio structurally broke since 2004. From 1978 to 2003, economic growth and financial development had a long-term co-integration, and it showed one-way supply relationship according to the Granger causality test, which means the economic growth have a slowly leading function to the development of finance. From 2004 to 2011, the correlation between them became weaker and had no Granger causality, but there had a long-term co-integration and mutual causality relationship existed between loan and GDP during the whole period. From it we can see loan could boost output more persistently. Therefore, the enhanced economic power of Jiangxi province could promote further development of regional financial service industries, and we would propose some related policy suggestions in this paper.

Testing statistical significance scores of sequence comparison methods with structure similarity

Directory of Open Access Journals (Sweden)

Leunissen Jack AM

2006-10-01

Full Text Available Abstract Background In the past years the Smith-Waterman sequence comparison algorithm has gained popularity due to improved implementations and rapidly increasing computing power. However, the quality and sensitivity of a database search is not only determined by the algorithm but also by the statistical significance testing for an alignment. The e-value is the most commonly used statistical validation method for sequence database searching. The CluSTr database and the Protein World database have been created using an alternative statistical significance test: a Z-score based on Monte-Carlo statistics. Several papers have described the superiority of the Z-score as compared to the e-value, using simulated data. We were interested if this could be validated when applied to existing, evolutionary related protein sequences. Results All experiments are performed on the ASTRAL SCOP database. The Smith-Waterman sequence comparison algorithm with both e-value and Z-score statistics is evaluated, using ROC, CVE and AP measures. The BLAST and FASTA algorithms are used as reference. We find that two out of three Smith-Waterman implementations with e-value are better at predicting structural similarities between proteins than the Smith-Waterman implementation with Z-score. SSEARCH especially has very high scores. Conclusion The compute intensive Z-score does not have a clear advantage over the e-value. The Smith-Waterman implementations give generally better results than their heuristic counterparts. We recommend using the SSEARCH algorithm combined with e-values for pairwise sequence comparisons.

Relationships Between Lower-Body Muscle Structure and, Lower-Body Strength, Explosiveness and Eccentric Leg Stiffness in Adolescent Athletes