Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 16 de 16
Filter
Add more filters










Publication year range
1.
PLoS One ; 19(5): e0302446, 2024.
Article in English | MEDLINE | ID: mdl-38701079

ABSTRACT

Various studies point to the lack of evidence of distributive opinion polarization in Europe. As most studies analyse the same item batteries from international social surveys, this lack of polarization might be due to an item's issue (e.g., the nature or substance of an item) or item formulation characteristics used to measure polarization. Based on a unique sample of 817 political attitudinal items asked in 2022 by respondents of a non-random online panel in Germany, we empirically assess the item characteristics most likely to lead to distributive opinion polarization-measured with the Van der Eijk agreement index. Our results show that only 20% of the items in our sample have some-at most moderate-level of opinion polarization. Moreover, an item's salience in the news media before the survey data collection, whether an item measures attitudes toward individual financial and non-financial costs, and the implicit level of knowledge required to answer an item (level of technicality) are significantly associated with higher opinion polarization. By contrast, items measuring a cultural issue (such as issues on gender, LGTBQI+, and ethnic minorities) and items with a high level of abstraction are significantly associated with a lower level of polarization. Our study highlights the importance of reflecting on the potential influence of an item's issue and item formulation characteristics on the empirical assessment of distributive opinion polarization.


Subject(s)
Attitude , Germany , Humans , Surveys and Questionnaires , Female , Male , Public Opinion , Politics
2.
Polymers (Basel) ; 16(9)2024 Apr 30.
Article in English | MEDLINE | ID: mdl-38732723

ABSTRACT

A promising therapeutic option for the treatment of critical-size mandibular defects is the implantation of biodegradable, porous structures that are produced patient-specifically by using additive manufacturing techniques. In this work, degradable poly(DL-lactide) polymer (PDLLA) was blended with different mineral phases with the aim of buffering its acidic degradation products, which can cause inflammation and stimulate bone regeneration. Microparticles of CaCO3, SrCO3, tricalcium phosphates (α-TCP, ß-TCP), or strontium-modified hydroxyapatite (SrHAp) were mixed with the polymer powder following processing the blends into scaffolds with the Arburg Plastic Freeforming 3D-printing method. An in vitro degradation study over 24 weeks revealed a buffer effect for all mineral phases, with the buffering capacity of CaCO3 and SrCO3 being the highest. Analysis of conductivity, swelling, microstructure, viscosity, and glass transition temperature evidenced that the mineral phases influence the degradation behavior of the scaffolds. Cytocompatibility of all polymer blends was proven in cell experiments with SaOS-2 cells. Patient-specific implants consisting of PDLLA + CaCO3, which were tested in a pilot in vivo study in a segmental mandibular defect in minipigs, exhibited strong swelling. Based on these results, an in vitro swelling prediction model was developed that simulates the conditions of anisotropic swelling after implantation.

3.
medRxiv ; 2023 Sep 06.
Article in English | MEDLINE | ID: mdl-37732233

ABSTRACT

Mental conditions exhibit a higher-order transdiagnostic factor structure which helps to explain the widespread comorbidity observed in psychopathology. However, the phenotypic and genetic structures of psychopathology may differ, raising questions about the validity and utility of these factors. Here, we study the phenotypic and genetic factor structures of ten psychiatric conditions using UK Biobank and public genomic data. Although the factor structure of psychopathology was generally genetically and phenotypically consistent, conditions related to externalizing (e.g., alcohol use disorder) and compulsivity (e.g., eating disorders) exhibited cross-level disparities in their relationships with other conditions, plausibly due to environmental influences. Domain-level factors, especially thought disorder and internalizing factors, were more informative than a general psychopathology factor in genome-wide association and polygenic index analyses. Collectively, our findings enhance the understanding of comorbidity and shared etiology, highlight the intricate interplay between genes and environment, and offer guidance for psychiatric research using polygenic indices.

4.
NPJ Sci Learn ; 8(1): 24, 2023 Jul 17.
Article in English | MEDLINE | ID: mdl-37460608

ABSTRACT

Estimates of shared environmental influence on educational attainment (EA) using the Classical Twin Design (CTD) have been enlisted as genetically sensitive measures of unequal opportunity. However, key assumptions of the CTD appear violated for EA. In this study we compared CTD estimates of shared environmental influence on EA with estimates from a Nuclear Twin and Family Design (NTFD) in the same 982 German families. Our CTD model estimated shared environmental influence at 43%. After accounting for assortative mating, our best fitting NTFD model estimated shared environmental influence at 26%, disaggregating this into twin-specific shared environments (16%) and environmental influences shared by all siblings (10%). Only the sibling shared environment captures environmental influences that reliably differ between families, suggesting the CTD substantially overestimates between-family differences in educational opportunity. Moreover, parental education was found to have no environmental effect on offspring education once genetic influences were accounted for.

5.
Biomater Sci ; 11(16): 5590-5604, 2023 Aug 08.
Article in English | MEDLINE | ID: mdl-37403758

ABSTRACT

Their excellent mechanical properties, degradability and suitability for processing by 3D printing technologies make the thermoplastic polylactic acid and its derivatives favourable candidates for biomaterial-based bone regeneration therapies. In this study, we investigated whether bioactive mineral fillers, which are known to promote bone healing based on their dissolution products, can be integrated into a poly(L-lactic-co-glycolic) acid (PLLA-PGA) matrix and how key characteristics of degradation and cytocompatibility are influenced. The polymer powder was mixed with particles of CaCO3, SrCO3, strontium-modified hydroxyapatite (SrHAp) or tricalcium phosphates (α-TCP, ß-TCP) in a mass ratio of 90 : 10; the resulting composite materials have been successfully processed into scaffolds by the additive manufacturing method Arburg Plastic Freeforming (APF). Degradation of the composite scaffolds was investigated in terms of dimensional change, bioactivity, ion (calcium, phosphate, strontium) release/uptake and pH development during long-term (70 days) incubation. The mineral fillers influenced the degradation behavior of the scaffolds to varying degrees, with the calcium phosphate phases showing a clear buffer effect and an acceptable dimensional increase. The amount of 10 wt% SrCO3 or SrHAp particles did not appear to be appropriate to release a sufficient amount of strontium ions to exert a biological effect in vitro. Cell culture experiments with the human osteosarcoma cell line SAOS-2 and human dental pulp stem cells (hDPSC) indicated the high cytocompatibility of the composites: For all material groups cell spreading and complete colonization of the scaffolds over the culture period of 14 days as well as an increase of the specific alkaline phosphatase activity, typical for osteogenic differentiation, were observed.


Subject(s)
Osteogenesis , Tissue Scaffolds , Humans , Tissue Scaffolds/chemistry , Glycols , Calcium Phosphates/chemistry , Minerals , Cell Differentiation , Strontium/chemistry , Printing, Three-Dimensional
6.
Behav Genet ; 53(2): 85-100, 2023 03.
Article in English | MEDLINE | ID: mdl-36378351

ABSTRACT

UK Biobank participants do not have a high-quality measure of intelligence or polygenic scores (PGSs) of intelligence to simultaneously examine the genetic and neural underpinnings of intelligence. We created a standardized measure of general intelligence (g factor) relative to the UK population and estimated its quality. After running a GWAS of g on UK Biobank participants with a g factor of good quality and without neuroimaging data (N = 187,288), we derived a g PGS for UK Biobank participants with neuroimaging data. For individuals with at least one cognitive test, the g factor from eight cognitive tests (N = 501,650) explained 29% of the variance in cognitive test performance. The PGS for British individuals with neuroimaging data (N = 27,174) explained 7.6% of the variance in g. We provided high-quality g factor estimates for most UK Biobank participants and g factor PGSs for UK Biobank participants with neuroimaging data.


Subject(s)
Biological Specimen Banks , Cognition , Humans , Neuropsychological Tests , Intelligence/genetics , Multifactorial Inheritance , United Kingdom/epidemiology
7.
Beilstein J Nanotechnol ; 2: 545-551, 2011.
Article in English | MEDLINE | ID: mdl-22003460

ABSTRACT

Cellular response to both surface topography and surface chemistry has been studied for several years. However, most of the studies focus on only one of the two parameters and do not consider their possible synergistic effects. Here, we report on a fabrication method for nanostructured surfaces composed of highly ordered arrays of silica nanocones with gold tips. By using a combination of block copolymer nanolithography, electroless deposition, and reactive ion etching several parameters such as structure height and structure distance could easily be adjusted to the desired values. The gold tips allow for easy functionalization of the substrates through a thiol linker system. Improved neural cell adhesion can be obtained and is dependent on the nature of the nanocone surface, thus illustrating the influence of different surface topographies on the nanometer length scale, on a complex cellular behavior such as cell adhesion. Substrate and surface functionality are shown to last over several days, leading to the conclusion that the features of our substrates can also be used for longer term experiments. Finally, initial neural cell adhesion is found to be more prominent on substrates with short intercone distances, which is an important finding for research dealing with the reactions of neuron-like tissue in the immediate moments after direct contact with an implanted surface.

9.
Biomaterials ; 31(2): 250-8, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19783042

ABSTRACT

Mechanical forces and geometric constraints play critical roles in determining cell functionality and tissue development. Novel experimental methods are essential to explore the underlying biological mechanisms of cell response. We present a versatile method to culture cells on adhesive micro-patterned substrates while applying long-term cyclic tensile strain (CTS). A polydimethysiloxane (PDMS) mold is coated with a cell repulsive NCO-sP(EO-stat-PO) hydrogel which in turn is covalently patterned by fibronectin using micro-contact printing. This results in two-dimensional, highly selective cell-adhesive micro-patterns. The substrates allow application of CTS to adherent cells for more than 4 days under cell culture conditions without unspecific adhesion. The applicability of our system is demonstrated by studying the adaptive response of C2C12 skeletal myoblasts seeded on fibronectin lines with different orientations relative to the strain direction. After application of CTS (amplitude of 7%, frequency of 0.5 Hz) we find that actin fiber organization is dominantly controlled by CTS. Nuclei shape is predominantly affected by the constraint of the adhesive lines, resulting in significant elongation. Morphologically, myotube formation was incomplete after 4 days of culture, but actin striations were observed exclusively on the 45 degrees line patterns subjected to CTS, the direction of maximum shear strain.


Subject(s)
Cell Shape/drug effects , Coated Materials, Biocompatible/pharmacology , Hydrogel, Polyethylene Glycol Dimethacrylate/chemistry , Hydrogel, Polyethylene Glycol Dimethacrylate/pharmacology , Myoblasts/cytology , Stress, Mechanical , Actins/metabolism , Animals , Cell Aggregation/drug effects , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Dimethylpolysiloxanes/pharmacology , Mice , Myoblasts/drug effects , Organelle Shape/drug effects , Stress Fibers/drug effects , Stress Fibers/metabolism
10.
Langmuir ; 26(2): 1051-6, 2010 Jan 19.
Article in English | MEDLINE | ID: mdl-19817353

ABSTRACT

We report a study on the interaction of the extracellular domain of trans-membrane proteins N-cadherin and L1 with nitrilotriacetic acid (NTA)-terminated self-assembled monolayers (SAMs) grown on silver and gold surfaces. Quartz crystal microbalance (QCM) and reflection absorption infrared spectroscopy (RAIRS) measurements reveal that upon addition of protein to an NTA-SAM there is a subsequent change in the mass and average chemical structure inside the films formed on the metal substrates. By using vibrational sum frequency generation (VSFG) spectroscopy and making a comparison to SAMs prepared with n-alkanethiols, we find that the formed NTA-SAMs are terminated by ethanol molecules from solution. The ethanol signature vanishes after the addition of L1, which indicates that the L1 proteins can interact specifically with the NTA complex. Although the RAIRS spectra display signatures in the amide and fingerprint regions, the VSFG spectra display only a weak feature at 866 cm(-1), which possibly indicates that some of the abundant phenyl rings in the complex are ordered. Although cell biology experiments suggest the directional complexation of L1, the VSFG experiments suggest that the alpha-helices and beta-sheets of L1 lack any preferential ordering.


Subject(s)
Capsid Proteins/chemistry , Gold/chemistry , Membranes, Artificial , Nitrilotriacetic Acid/chemistry , Silver/chemistry , Cadherins/chemistry , Models, Theoretical , Protein Structure, Tertiary , Surface Properties
11.
Nano Lett ; 9(12): 4115-21, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19694460

ABSTRACT

The density/spacing of plasma membrane proteins is thought to be crucial for their function; clear-cut experimental evidence, however, is still rare. We examined nanopatterns biofunctionalized with cell adhesion molecule DM-GRASP with respect to their impact on neuron attachment and neurite growth. Data analysis/modeling revealed that these cellular responses improve with increasing DM-GRASP density, with the exception of one spacing which does not allow for the anchorage of a cytoskeletal protein (spectrin) to three DM-GRASP molecules.


Subject(s)
Nanostructures/chemistry , Nanostructures/ultrastructure , Nanotechnology/methods , Neural Cell Adhesion Molecules/chemistry , Neurons/cytology , Neurons/physiology , Tissue Engineering/methods , Animals , Cell Adhesion , Cell Differentiation , Cells, Cultured , Crystallization/methods , Macromolecular Substances/chemistry , Materials Testing , Molecular Conformation , Neurons/chemistry , Particle Size , Surface Properties
12.
BMC Cell Biol ; 9: 64, 2008 Dec 04.
Article in English | MEDLINE | ID: mdl-19055842

ABSTRACT

BACKGROUND: Molecular spacing is important for cell adhesion in a number of ways, ranging from the ordered arrangement of matrix polymers extracellularly, to steric hindrance of adhesion/signaling complexes intracellularly. This has been demonstrated using nanopatterned RGD peptides, a canonical extracellular matrix ligand for integrin interactions. Cell adhesion was greatly reduced when the RGD-coated nanoparticles were separated by more than 60 nm, indicating a sharp spacing-dependent threshold for this form of cell adhesion. RESULTS: Here we show a similar dependence of cell adhesion on the spacing of agrin, a protein that exists as both a secreted, matrix-bound form and a type-2 transmembrane form in vivo. Agrin was presented as a substrate for cell adhesion assays by anchoring recombinant protein to gold nanoparticles that were arrayed at tunable distances onto glass coverslips. Cells adhered well to nanopatterned agrin, and when presented as uniformly coated substrates, adhesion to agrin was comparable to other well-studied adhesion molecules, including N-Cadherin. Adhesion of both mouse primary cortical neurons and rat B35 neuroblastoma cells showed a spacing-dependent threshold, with a sharp drop in adhesion when the space between agrin-coated nanoparticles increased from 60 to 90 nm. In contrast, adhesion to N-Cadherin decreased gradually over the entire range of distances tested (uniform, 30, 60, 90, and 160 nm). The spacing of the agrin nanopattern also influenced cell motility, and peptide competition suggested adhesion was partially integrin dependent. Finally, differences in cell adhesion to C-terminal agrin fragments of different lengths were detected using nanopatterned substrates, and these differences were not evident using uniformly coated substrates. CONCLUSION: These results suggest nanopatterned substrates may provide a physiological presentation of adhesive substrates, and are consistent with cells adhering to agrin through a mechanism that more closely resembles an interaction with the extracellular matrix than a transmembrane adhesion molecule.


Subject(s)
Agrin/metabolism , Cell Adhesion Molecules/metabolism , Cell Membrane/metabolism , Extracellular Matrix/metabolism , Animals , Apoptosis , Cell Adhesion , Cell Line, Tumor , Humans , Mice , Nanostructures , Protein Binding , Rats , Substrate Specificity
13.
Biointerphases ; 2(1): 1-5, 2007 Mar.
Article in English | MEDLINE | ID: mdl-20408630

ABSTRACT

Living confluent fish fibroblast cells RTG-P1 from rainbow trout adherent on diamond were examined by attenuated total reflection (ATR) infrared (IR) spectroscopy. In particular, IR spectra were recorded dynamically during the adsorption of the cells onto the diamond and during their biochemically induced structural responses to the subsequent addition of trypsin and cytochalasin D. It is shown that changes in the IR spectra result from changes in cell morphology and surface coverage. The results demonstrate the potential and the applicability of ATR IR spectroscopy for live cell adhesion assays.

14.
Biointerphases ; 2(1): 44-8, 2007 Mar.
Article in English | MEDLINE | ID: mdl-20408635

ABSTRACT

The authors describe the deposition of single biomolecules on substrates at defined spacing by pure self-assembly. The substrate is equipped with an array of 8 nm large gold particles which form the template for biomolecule binding. The authors verified the successful binding of single biomolecules via specific antibody labeling and imaging by fluorescence microscopy. Scanning force microscopy provided evidence that every gold nanoparticle of the pattern is occupied by at least one biomolecule. Furthermore, gold conjugated secondary antibodies in combination with scanning electron microscopy proved that at least 75% of the nanoparticles carried only one active biomolecule. The precision given by such surface densities is molecularly defined and such considerably higher than in any other case reported so far.

15.
Soft Matter ; 3(12): 1486-1491, 2007 Nov 14.
Article in English | MEDLINE | ID: mdl-32900102

ABSTRACT

Adhesion and neurite formation of neurons and neuroblastoma cells critically depends on the lateral spacing of the cell adhesion molecule DM-GRASP offered as nanostructured substrate.

16.
J Biol Chem ; 278(45): 44457-66, 2003 Nov 07.
Article in English | MEDLINE | ID: mdl-12941935

ABSTRACT

All type I DnaJ (Hsp40) homologues share the presence of two highly conserved zinc centers. To elucidate their function, we constructed DnaJ mutants that separately replaced cysteines of either zinc center I or zinc center II with serine residues. We found that in the absence of zinc center I, the autonomous, DnaK-independent chaperone activity of DnaJ is dramatically reduced. Surprisingly, this only slightly impaired the in vivo function of DnaJ, and its ability to function as a co-chaperone in the DnaK/DnaJ/GrpE foldase machine. The DnaJ zinc center II, on the other hand, was found to be absolutely essential for the in vivo and in vitro function of DnaJ. This did not seem to be caused by a lack of substrate binding affinity or an inability to work as an ATPase-stimulating factor. Rather it appears that zinc center II mutant proteins lack a necessary additional interaction site with DnaK, which seems to be crucial for locking-in substrate proteins onto DnaK. These findings led us to a model in which ATP hydrolysis in DnaK is only the first step in converting DnaK into its high affinity binding state. Additional interactions between DnaK and DnaJ are required to make the DnaK/DnaJ/GrpE foldase machinery catalytically active.


Subject(s)
Escherichia coli Proteins , Heat-Shock Proteins/chemistry , Heat-Shock Proteins/physiology , Zinc/metabolism , Adenosine Triphosphatases/metabolism , Adenosine Triphosphate/metabolism , Bacterial Proteins/metabolism , Binding Sites , Circular Dichroism , Cysteine , Drug Interactions , Escherichia coli/chemistry , Escherichia coli/genetics , Gene Deletion , Gene Expression , HSP40 Heat-Shock Proteins , HSP70 Heat-Shock Proteins/metabolism , Heat-Shock Proteins/genetics , Heat-Shock Proteins/metabolism , Hot Temperature , Hydrolysis , Luciferases/chemistry , Luciferases/metabolism , Models, Molecular , Molecular Chaperones/physiology , Molecular Structure , Mutagenesis, Site-Directed , Plasmids/genetics , Protein Conformation , Protein Folding , Serine , Structure-Activity Relationship , Transfection
SELECTION OF CITATIONS
SEARCH DETAIL
...