Towards Steering Magnetic Nanoparticles in Drug Targeting Using a Linear Halbach Array

Magnetic nanoparticles offer numerous promising biomedical applications, e.g. magnetic drug targeting. Here, magnetic drug carriers inside the human body are directed towards tumorous tissue by an external magnetic field. However, the success of the treatment strongly depends on the amount of drug carriers, reaching the desired tumor region. This steering process is still an open research topic. In this paper, the previous study of a linear Halbach array is extended by an additional Halbach array with different magnetization angles between two adjacent magnets and investigated numerically using COMSOL Multiphysics. The Halbach arrays are arranged with permanent magnets and generate a relatively large region of a moderately homogeneous, high magnetic field while having a strong gradient. This results in a strong magnetic force, trapping many particles at the magnets. Afterwards, to avoid particle agglomeration, the Halbach array is flipped to its weak side. Therefore, the magnetic flux density, its gradient and the resulting magnetic force are computed for the different Halbach arrays with different constellations of magnetization directions. Since the calculation of the gradient can lead to high errors due to the used mesh in Comsol, the gradient was derived analytically by investigating two different fitting functions. Overall, the array with a 90∘ shifted magnetization performs best, changing the magnetic sides of the array easily and deflecting more particles. Besides, the results revealed that the magnetic force dominates directly underneath the magnets compared to the other existing forces on the SPIONS. Summarized, the results depict that the magnetic force and, thus, the region where the particles are able to get washed out, can be adjusted using low-cost permanent magnets.</p

Towards Differential Static Magnetic Localization of Commercial Capsule Endoscopes: An Evaluation Using Different Ring and Cylindrical Magnets

Capsule endoscopy is a promising diagnostic tool for the entire gastrointestinal tract. Since a patient swallows the capsules, their size must be sufficiently small. The principal built-in components are cameras, silver-oxide batteries, light emitting diodes, and an antenna for transmitting the video. For diagnosis and treatment, the precise localization of the capsules for specific video frames is required. Recently, static magnetic localization of these capsules with an integrated permanent magnet showed promising results. However, in the state-of-the-art, relatively large magnets compared to the small capsules were used. Therefore, in this extended paper, the localization performance of a recently proposed optimized differential static magnetic localization method for different sized disc and ring magnets was evaluated. The ring magnets were designed for integration with the two batteries of commercial capsules. The magnets were evaluated in static and dynamic scenarios to evaluate the performance of the method in a patient's daily life. It was revealed that the mean position and orientation errors did not exceed 5 mm and 4∘, respectively, for all applied magnets except for the 1.5 and 3 mm long disc magnets. Moreover, the results indicated that the ferromagnetic batteries of capsule endoscopes increase the localization performance when they are centered within a diametrical ring magnet. Overall, it was revealed that the localization performance of the optimized differential method is significantly better than the state-of-the-art even when the magnet volume is significantly reduced compared to previous work. Therefore, it was concluded that 5 mm long disc magnet or a ring magnet are excellent candidates for integration into a commercial capsule for magnetic localization and yield the advantage of being passive magnetic sources.</p

Within-trait heterogeneity in age group differences in personality domains and facets:implications for the development and coherence of personality traits

The study investigated differences in the Five-Factor Model (FFM) domains and facets across adulthood. The main questions were whether personality scales reflected coherent units of trait development and thereby coherent personality traits more generally. These questions were addressed by testing if the components of the trait scales (items for facet scales and facets for domain scales) showed consistent age group differences. For this, measurement invariance (MI) framework was used. In a sample of 2,711 Estonians who had completed the NEO Personality Inventory 3 (NEO PI-3), more than half of the facet scales and one domain scale did not meet the criterion for weak MI (factor loading equality) across 12 age groups spanning ages from 18 to 91 years. Furthermore, none of the facet and domain scales met the criterion for strong MI (intercept equality), suggesting that items of the same facets and facets of the same domains varied in age group differences. When items were residualized for their respective facets, 46% of them had significant (p < 0.0002) residual age-correlations. When facets were residualized for their domain scores, a majority had significant (p < 0.002) residual age-correlations. For each domain, a series of latent factors were specified using random quarters of their items: scores of such latent factors varied notably (within domains) in correlations with age. We argue that manifestations of aetiologically coherent traits should show similar age group differences. Given this, the FFM domains and facets as embodied in the NEO PI-3 do not reflect aetiologically coherent traits

A Basic Bivariate Structure of Personality Attributes Evident Across Nine Languages

(Objective:) Here, two studies seek to characterize a parsimonious common-denominator personality structure with optimal cross-cultural replicability. Personality differences are observed in all human populations and cultures, but lexicons for personality attributes that contain so many distinctions that parsimony is lacking. Models stipulating the most important attributes have been formulated by experts or by empirical studies drawing on experience in a very limited range of cultures. (Method:) Factor-analyses of personality lexicons of nine languages of diverse provenance (Chinese, Korean, Filipino, Turkish, Greek, Polish, Hungarian, Maasai, and Senoufo) were examined, and their common structure compared to that of several prominent models in psychology. (Results:) A parsimonious bivariate model showed evidence of substantial convergence and ubiquity across cultures. Analyses involving key markers of these dimensions in English indicate that they are broad dimensions involving the overlapping content of the interpersonal circumplex, models of communion and agency, and of morality/warmth and competence. (Conclusions:) These “Big Two” dimensions – Social Self-Regulation and Dynamism – provide a common-denominator model involving the two most crucial axes of personality variation, ubiquitous across cultures.The Big Two might serve as an umbrella model serving to link diverse theoretical models and associated research literatures

Cross-Cultural Differences in a Global “Survey of World Views”

10.1177/0022022114551791We know that there are cross-cultural differences in psychological variables, such as individualism/collectivism. But it has not been clear which of these variables show relatively the greatest differences. The Survey of World Views project operated from the premise that such issues are best addressed in a diverse sampling of countries representing a majority of the world¿s population, with a very large range of item-content. Data were collected online from 8,883 individuals (almost entirely college students based on local publicizing efforts) in 33 countries that constitute more than two third of the world¿s population, using items drawn from measures of nearly 50 variables. This report focuses on the broadest patterns evident in item data. The largest differences were not in those contents most frequently emphasized in cross-cultural psychology (e.g., values, social axioms, cultural tightness), but instead in contents involving religion, regularity-norm behaviors, family roles and living arrangements, and ethnonationalism. Content not often studied cross-culturally (e.g., materialism, Machiavellianism, isms dimensions, moral foundations) demonstrated moderate-magnitude differences. Further studies are needed to refine such conclusions, but indications are that cross-cultural psychology may benefit from casting a wider net in terms of the psychological variables of focus