384 research outputs found
The Antecedents and Consequences of Body Image Dissatisfaction: A Structural Modeling Analysis and a Controlled Laboratory Task
Recent covariance structural equation modeling investigations have begun to examine factors thought to play a role in body image dissatisfaction and eating disturbance (Thompson et al., 1999). The current investigation extended this line of research using structural equation modeling to examine a tripartite model of body image dissatisfaction. Female participants (N = 200) completed an informed consent, the Survey of Background Information, the Body Comparison Scale, the Restraint Scale, the Three Factor Eating Questionnaire, the Body Esteem Scale-Revised, the Inventory of Peer Influence on Eating Concerns, the Perception of Teasing Scale, the Eating Disorders Inventory, the Parent Involvement Scale, the Sociocultural Attitudes Towards Appearance Scale-Revised, the Perceived Sociocultural Pressure Scale, and the Symptoms Checklist 90-Revised.
In addition, a laboratory-based, controlled experiment was used to investigate the role of social comparison in the development of body image dissatisfaction resulting from exposure to media images of thinness and attractiveness. Based on responses to the Body Comparison Scale, two groups of women were identified from the original sample: those with a high pre-existing tendency to engage in social comparison (n = 30) and those with a low pre-existing tendency to engage in social comparison (n = 30). After completing a Survey of Background Information, half of each group of women watched commercials that epitomized societal ideals of thinness and attractiveness; whereas, half of each group of women viewed commercials that did not focus on appearance. Upon completion of the commercial video clips, each participant completed the Eating Disorders Inventory and the Body Comparison Scale.
The present study did not support the tripartite models of body image dissatisfaction, as the data did not adequately fit either of the two proposed models. However, the data did support an alternative multidimensional model of body image disturbance and several of the specific hypothesized effects. Analyses examining the effects of the type of video viewed on social comparison yielded significant between-group differences, but failed to yield significant interactions between women’s pre-existing tendency to engage in social comparison and the type of video viewed across the two assessments. Further, analyses examining the role of social comparison in body image dissatisfaction yielded significant interactions for video condition by pre-post trial and social comparison by pre-post trial
Comparative HPLC-MSn analysis of canine and human meibomian lipidomes: many similarities, a few differences
The aim of this study was to evaluate the lipidome of meibomian gland
secretions in canines (cMGS) – a common pet and laboratory animal – and to
compare it with that of human MGS (hMGS), to determine whether canines could
be used as a valid experimental animal model in studies of the biochemistry
and physiology of the human ocular surface in general, and of the Meibomian
glands in particular. The MGS of both species were evaluated using HPLC in
combination with atmospheric pressure chemical ionization ion trap mass
spectrometry. The main lipid classes found in cMGS were very long chain
cholesteryl esters, wax esters, (O-acyl)-omega-hydroxy fatty acids (OAHFA),
and cholesteryl esters of OAHFA. The lipidomes of cMGS and hMGS were found to
be qualitatively similar, which implies similar biosynthetic and
biodegradation pathways in canines and humans. However, some quantitative
differences between the two were observed
Optimising DNA binding to carbon nanotubes by non-covalent methods
The use of carbon nanotubes as a gene delivery system has been extensively studied in recent years owing to its potential advantages over viral vectors. To achieve this goal, carbon nanotubes have to be functionalized to become compatible with aqueous media and to bind the genetic material. To establish the best conditions for plasmid DNA binding, we compare the dispersion properties of single-, double- and multi-walled carbon nanotubes (SWCNTs, DWCNTs and MWCNTs, respectively) functionalized with a variety of surfactants by non-covalent attachment. The DNA binding properties of the functionalized carbon nanotubes were studied and compared by electrophoresis. Furthermore, a bilayer functionalization method for DNA binding on SWCNTs was developed that utilized RNA-wrapping to solubilize the nanotubes and cationic polymers as a bridge between nanotubes and DNA
Application of novel image base estimation of invisible leaf injuries in relation to morphological and photosynthetic changes of Phaseolus vulgaris L. exposed to tropospheric ozone
This study aimed to evaluate the degree of Phaseolus vulgaris L. (bean) leaf tissue injury caused by
tropospheric ozone. To validate O3 symptoms at the microscopic level, Evans blue staining together with
an image processing method for the removal of distortions and calculation of dead leaf areas was applied.
Net photosynthetic rate (PN), stomatal conductance (gs) and intercellular CO2 concentration (Ci) were
determined to evaluate leaf physiological responses to ozone. It was found that both resistant and
sensitive varieties of bean were damaged by ozone; however, the size of necrotic and partially destroyed
leaf area in the sensitive genotype (S156) was bigger (1.18%, 2.18%) than in the resistant genotype (R123),
i.e. 0.02% and 0.50%. Values of net photosynthetic rates were lower in the sensitive genotype in ambient
air conditions, than in the resistant genotype in ambient air conditions. We further found that there was
a correlation between physiological and anatomical injuries; net photosynthetic rate (PN) was negatively
correlated with percentage of necrotic area of both genotypes, while stomatal conductance (gs), intercellular
CO2 concentration (Ci) were positively correlated with percentage of necrotic tissue of both genotypes. Moreover, visible injures in both genotypes were positively correlated with percentage of anatomical injures. In conclusion, the presented combinations of morphological, anatomical and physiological markers allowed differential diagnosis of ozone injury
On the formation process of silicon carbide nanophases via hydrogenated thermally induced templated synthesis
A thermally induced templated synthesis for SiC nanotubes and nanofibers
using ammonia or nitrogen as a carrier gas, single wall carbon nanotubes
(SWCNT) as templates as well as gaseous Si is presented. The bundles of SWCNT
act as both the carbon source and as a nanoframe from which SiC structuctures
form. Depending on the duration of the thermally induced templated reaction,
for a fixed temperature, carrier gas, and gas pressure, various SiC
nanostructures are obtained. These structures include SiC nanorods coated in C,
SiC nanorods, SiC nanotubes, and SiC nanocrytals. From our analysis using
transmission electron microscopy (TEM) and scanning electron microscopy (SEM),
electron energy-loss spectroscopy (EELS), electron diffraction (EDX), optical
absorption spectroscopy and Raman spectroscopy as probes we prove that H has a
key role on the morphology and stochiometry of the different SiC
nanostructures.Comment: 9 pages, 2 Figure
Pressure dependence of Raman modes in double wall carbon nanotubes filled with α-Fe.
The preparation of highly anisotropic one-dimensional (1D) structures confined into carbon nanotubes (CNTs) in general is a key objective in CNTs research. In this work, the capillary effect was used to fill double wall carbon nanotubes with iron. The samples are characterized by Mössbauer and Raman spectroscopy, transmission electron microscopy, scanning area electron diffraction, and magnetization. In order to investigate their structural stability and compare it with that of single wall carbon nanotubes (SWNTs), elucidating the differences induced by the inner-outer tube interaction, unpolarized Raman spectra of tangential modes of double wall carbon nanotubes (DWNTs) filled with 1D nanocrystallin α-Fe excited with 514 nm were studied at room temperature and elevated pressure. Up to 16 GPa we find a pressure coefficient for the internal tube of 4.3 cm−1 GPa−1 and for the external tube of 5.5 cm−1 GPa−1. In addition, the tangential band of the external and internal tubes broadens and decreases in amplitude. All findings lead to the conclusion that the outer tube acts as a protection shield for the inner tubes (at least up 16 GPa). Structural phase transitions were not observed in this range of pressure
Chloroquine-enhanced gene delivery mediated by carbon nanotubes
Polyethyleneimine-coated double-walled carbon nanotubes (DWCNTs) were used for dual gene and drug delivery, after loading the DWCNTs with the drug chloroquine, a lysosomotropic compound that is able to promote escape from the lysosomal compartment. Different forms of functionalization of the DWCNTs were examined in order to optimize this system. They included the testing of different treatments on DWCNTs to optimize the loading and delivery of chloroquine and the selection of a cationic polymer for coating the DWCNTs for optimum DNA binding and delivery. An acid oxidation treatment of DWCNTs was selected for optimum chloroquine loading together with polyethyleneimine as optimum cationic coating agent for plasmid DNA binding. Optimization of the conditions for choroquine-enhanced gene delivery were developed using luciferase expression as a model system. We have demonstrated that chloroquine-loading increases the ability of polyethyleneimine-coated DWCNTs to deliver functional nucleic acid to human cells. Cell viability tests have shown no cytotoxicity of the functionalized DWCNTs at the concentrations needed for optimum gene delivery. These results support the potential applications of this methodology in gene therapy
BN domains included into carbon nanotubes: role of interface
We present a density functional theory study on the shape and arrangement of
small BN domains embedded into single-walled carbon nanotubes. We show a strong
tendency for the BN hexagons formation at the simultaneous inclusion of B and N
atoms within the walls of carbon nanotubes. The work emphasizes the importance
of a correct description of the BN-C frontier. We suggest that BN-C interface
will be formed preferentially with the participation of N-C bonds. Thus, we
propose a new way of stabilizing the small BN inclusions through the formation
of nitrogen terminated borders. The comparison between the obtained results and
the available experimental data on formation of BN plackets within the single
walled carbon nanotubes is presented. The mirror situation of inclusion of
carbon plackets within single walled BN nanotubes is considered within the
proposed formalism. Finally, we show that the inclusion of small BN plackets
inside the CNTs strongly affects the electronic character of the initial
systems, opening a band gap. The nitrogen excess in the BN plackets introduces
donor states in the band gap and it might thus result in a promising way for
n-doping single walled carbon nanotubes
Does wage rank affect employees' well-being?
How do workers make wage comparisons? Both an experimental study and an analysis of 16,000 British employees are reported. Satisfaction and well-being levels are shown to depend on more than simple relative pay. They depend upon the ordinal rank of an individual's wage within a comparison group. “Rank” itself thus seems to matter to human beings. Moreover, consistent with psychological theory, quits in a workplace are correlated with pay distribution skewness
- …