901 research outputs found
Visual adaptation to thin and fat bodies transfers across identity
Visual perception is highly variable and can be influenced by the surrounding world. Previous research has revealed that body perception can be biased due to adaptation to thin or fat body shapes. The aim of the present study was to show that adaptation to certain body shapes and the resulting perceptual biases transfer across different identities of adaptation and test stimuli. We designed two similar adaptation experiments in which healthy female participants adapted to pictures of either thin or fat bodies and subsequently compared more or less distorted pictures of their own body to their actual body shape. In the first experiment (n = 16) the same identity was used as adaptation and test stimuli (i.e. pictures of the participant’s own body) while in the second experiment (n = 16) we used pictures of unfamiliar thin or fat bodies as adaptation stimuli. We found comparable adaptation effects in both experiments: After adaptation to a thin body, participants rated a thinner than actual body picture to be the most realistic and vice versa. We therefore assume that adaptation to certain body shapes transfers across different identities. These results raise the questions of whether some type of natural adaptation occurs in everyday life. Natural and predominant exposure to certain bodily features like body shape – especially the thin ideal in Western societies – could bias perception for these features. In this regard, further research might shed light on aspects of body dissatisfaction and the development of body image disturbances in terms of eating disorders
Untersuchungen zur Präsentation von endogenen Antigenen auf MHC-Klasse-I- und MHC-Klasse-II-Molekülen
Grundlage für die Entstehung adaptiver Immunantworten ist die Präsentation von Antigenen auf MHC-Klasse-I- und MHC-Klasse-II-Molekülen. Die hierfür verantwortlichen Antigen-Prozessierungswege sind weitgehend aufgeklärt, jedoch ist die molekulare Basis der Antigen-Auswahl noch immer unverstanden. Neuere Untersuchungen verschiedener Arbeitsgruppen zeigten, dass Antigene, die über endogene Präsentationswege auf MHC-Moleküle geladen werden, vornehmlich von neusynthetisierten und nicht von maturen Proteinen abstammen. Wie und welcher Teil der neusynthetisierten Translationsprodukte ausgewählt und in die Antigenpräsentationswege dirigiert wird und ob biochemische Charakteristika der Antigene die Auswahl beeinflussen, ist noch ungeklärt.
In der vorliegenden Arbeit wurden verschiedene Postulate und Hypothesen zur Antigen-Auswahl und -Präsentation untersucht: (1) der Beitrag von Defective Ribosomal Products (DRiP) sowie (2) prä-mRNA-Translationsprodukten zum Antigenpool und (3) der Einfluss von Antigen-mRNA-Stabilität. Desweiteren wurden (4) der Einfluss biochemischer Eigenschaften, sowie Größe der Antigene auf die Präsentation und (5) die Beteiligung verschiedener Autophagie-Komponenten und des mTOR-Signalwegs in der Antigenpräsentation studiert.
Um die DRiP-Hypothese zu überprüfen, wurde die Präsentation des Modellantigens Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) und der instabilen Variante CFTR∆F508 auf MHC-Klasse-I-Molekülen untersucht. Nach Expression in Zielzellen wurden Antigene aus beiden Proteinen mit ähnlicher Effizienz präsentiert und die Behandlung mit CFTR-Faltungsmodulatoren, die zu erhöhten Proteinspiegeln führte, hatte keinen Einfluss auf die T-Zellerkennung. Für dieses Modellantigen konnten somit keine Anhaltspunkte für einen Beitrag von DRiP zum Antigenpool gefunden werden.
Die Bedeutung von prä-mRNA-Translationsprodukten als Antigenquelle wurde durch den Vergleich der Präsentation von Exon- und Intron-kodierten T-Zellepitopen untersucht. Eine T-Zellerkennung Intron-kodierter Epitope erfolgte nur nach Mutation der Spleiß-Stellen und der dadurch bedingten Translation von Intronsequenzen. Neben fehlenden Evidenzen für einen bedeutenden Beitrag von prä-mRNA-Translationsprodukten zum Antigenpool lieferten diese und weitere Untersuchungen auch keine Hinweise auf einen Einfluss der Antigenmenge und der Antigen-mRNA-Stabilität auf die Antigenpräsentation.
Untersuchungen zur endogenen Präsentation eines Modellantigens auf MHC-Klasse-II-Molekülen ergaben, dass sowohl die Länge des Polypeptids als auch seine Aminosäuresequenz einen großen Einfluss auf die Autophagie-abhängige Präsentation des Antigens haben. Durch Verwendung verschiedener chemischer Inhibitoren wurden Hinweise auf eine mTOR-unabhängige Regulation dieses Präsentationswegs erhalten.Basis for the development of adaptive immune response is the presentation of antigens on MHC class I and II molecules. While the pathways involved in antigen processing have been extensively studied, the molecular basis for the selection of antigens still remains unknown. Recent results from different labs showed that antigens loaded on MHC molecules via endogenous presentation pathways are mainly derived from newly synthesized and not from mature proteins. How and which fraction of the newly synthesized translation products is selected and channeled into presentation pathways and whether biochemical characteristics of antigens influence the selection, is still unclear.
In this study, different theories and hypotheses regarding antigen selection and presentation were analyzed: (1) the contribution of Defective Ribosomal Products (DRiP) and (2) pre-mRNA translation products to the antigen pool, (3) the influence of mRNA stability and (4) biochemical properties as well as size of polypeptides on antigen presentation, and (5) the involvement of different components of autophagy and of the mTOR signaling pathway in antigen presentation.
In order to examine the DRiP hypothesis, the presentation of the model antigen Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and the instable CFTR∆F508 variant on MHC class I molecules was analyzed. Following expression in target cells, antigens from both proteins were presented with similar efficiency and treatment with CFTR folding modulators, which resulted in increased protein levels, had no effect on T-cell recognition. Thus, no evidence for a significant contribution of DRiP to the antigenic pool was obtained for this model antigen.
The relevance of pre-mRNA translational products in antigen presentation was investigated by comparing T-cell recognition of epitopes derived from exon sequences to those derived from intron sequences. T cells recognized intronic epitopes only if the splicing sites were mutated and, consequently, when intron sequences became part of the open reading frame. Besides challenging the relevance of pre-mRNA translational products for the antigenic pool, these and additional experiments also demonstrated that the abundance of the antigenic protein, or the stability of the antigen mRNA, does not correlate with efficiency of antigen presentation.
Analysis of endogenous presentation of a model antigen on MHC class II molecules demonstrated that size and amino acid composition of the antigenic polypeptide has a major effect on autophagy-dependent antigen presentation. By using different chemical inhibitors, a mTOR-independent regulation of this antigen presentation pathway was revealed
EFFECTS OF AN 8-WEEK KNEE INJURY PREVENTION PROGRAM AND TECHNIQUE MODIFICATION TRAINING ON CHANGE-OF-DIRECTION PERFORMANCE
The purpose of this analysis was to determine whether an 8-week knee injury prevention program with an additional focus on change-of-direction (COD) technique training results in improved COD performance compared to a control training group with a focus on linear sprint training. Although both groups showed indicators for superior performance during a 135-degree COD, such as a more effective reorientation of the body, the COD technique modification component was ineffective in improving overall COD completion time or ground contact times. Follow-up analyses will show whether the COD group adopted a safer COD movement strategy following training, e.g. by reducing the knee valgus loading
Lower tidal volume at initiation of mechanical ventilation may reduce progression to acute respiratory distress syndrome: A systematic review
INTRODUCTION: The most appropriate tidal volume in patients without acute respiratory distress syndrome (ARDS) is controversial and has not been rigorously examined. Our objective was to determine whether a mechanical ventilation strategy using lower tidal volume is associated with a decreased incidence of progression to ARDS when compared with a higher tidal volume strategy. METHODS: A systematic search of MEDLINE, EMBASE, CINAHL, the Cochrane Library, conference proceedings, and clinical trial registration was performed with a comprehensive strategy. Studies providing information on mechanically ventilated patients without ARDS at the time of initiation of mechanical ventilation, and in which tidal volume was independently studied as a predictor variable for outcome, were included. The primary outcome was progression to ARDS. RESULTS: The search yielded 1,704 studies, of which 13 were included in the final analysis. One randomized controlled trial was found; the remaining 12 studies were observational. The patient cohorts were significantly heterogeneous in composition and baseline risk for developing ARDS; therefore, a meta-analysis of the data was not performed. The majority of the studies (n = 8) showed a decrease in progression to ARDS with a lower tidal volume strategy. ARDS developed early in the course of illness (5 hours to 3.7 days). The development of ARDS was associated with increased mortality, lengths of stay, mechanical ventilation duration, and nonpulmonary organ failure. CONCLUSIONS: In mechanically ventilated patients without ARDS at the time of endotracheal intubation, the majority of data favors lower tidal volume to reduce progression to ARDS. However, due to significant heterogeneity in the data, no definitive recommendations can be made. Further randomized controlled trials examining the role of lower tidal volumes in patients without ARDS, controlling for ARDS risk, are needed. 2013 Fuller et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Applying scattered wave tomography and joint inversion of high density (SWATH D) geophysical and petrophysical datasets to unravel Eastern Alpine crustal structure
This project harnesses the high density of seismic stations in AlpArray and the AlpArray complementary experiment SWATH D to significantly improve the resolution and reliability of the subsurface models by enabling the use of many different inversion methods to obtain and integrate the different results. These advanced models are vital for resolving the complex Alpine plate configuration and understanding how the crustal structure seen today reflects the dramatic changes in mountain building style and reorganisation of plate boundaries at about 20 Ma. We employ the joint inversion of seismological and petrophysical data sets in order to understand the intra-crustal structure, temperature, and petrophysical properties of crustal layers by inverting seismic data directly for the crust’s constituent mineral assemblages. Teleseismic full waveform inversion (FWI) provides a powerful tool for illuminating both the crustal and, complementing the joint inversion, intra-crustal structure. In our application of FWI, we increase the frequency content with the progression of the inversion.
To perform FWI with teleseismic data at low frequencies, we couple the 1D code Gemini (Friederich and Dalkolmo, 1995) with the 3D code SPECFEM3D Cartesian for forward modelling and use the FWI code ASKI (Schumacher and Friederich, 2016) for computing waveform sensitivity kernels and performing the inversion. At higher frequencies we opt for a ray theory-based approach rather than full waveform modelling due to its high computational cost. We calculate high frequency P-phase synthetic seismograms by coupling various codes to obtain travel times, amplitudes and source time functions. ObsPy TauP, a 1D code, is used to determine travel times and ray paths in the bulk earth, while FM3D (de Kool et al., 2006), a 3D code, is employed in the study area. Subsequently, the ray paths are used to calculate amplitudes via dynamic ray tracing. Source time functions are obtained by fitting the recorded data. We intend to use the P-phase synthetic seismograms within the framework of ASKI to compute waveform sensitivity kernels. Subsequent inversion with these kernels could improve the resolution of the resulting models.
First results of FWI at low frequencies up to 0.1 Hz (using the coupled Gemini-SPECFEM3D code for forward modelling) demonstrate a good agreement with the P-wave velocity models obtained from teleseismic travel time tomography by Paffrath et al. (2021) as part of the first phase of the SPP. Though derived from Fourier-transformed waveform data and currently only 24 events, the FWI model reduces the variance of the P-wave travel time residuals data set by 60 percent. Moreover, the FWI models exhibit surprisingly high resolution in the crust and uppermost mantle with a superb image of the Alpine and Apennine orogenic root and the Ivrea body probably by virtue of the presence of reflected and converted P- and S-phases in the considered time windows.
Receiver functions and surface wave dispersion curves, calculated in partner projects, are usually jointly inverted for elastic properties. By utilising the strengths of Markov Chain Monte Carlo inversion, we are able to instead parameterise our model by temperature and mineral assemblage. This allows the introduction of geological-mineralogical constraints, in a probabilistic self-consistent manner, to the inversion. A further significant advantage is in interpretation where the probabilities of certain lithologies being present allows for a more seamless integration of qualitative geological data and a reduction in interpretation biases present when only seismic velocities are presented
Phonology of hunting signs in two Kalahari-Khoe speaking groups (Ts'ixa and ||Ani)
Phonology of hunting signs in two Kalahari-Khoe speaking groups (Ts'ixa and ||Ani
Integrating Combined First Trimester Screening for Preeclampsia into Routine Ultrasound Examination.
Introduction The Fetal Medicine Foundation (FMF) London has developed a first trimester screening algorithm for preeclampsia (PE), based on maternal characteristics and past risk factors, mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), and placental growth factor (PlGF). The aim of this study was to determine the feasibility of integrating PE screening into routine practice.
Material and Methods All pregnancies with a fetal crown-rump length of 45 - 84 mm presenting to our ultrasound department between January 2014 and September 2020 were included in this analysis. Screening for PE was offered to singleton pregnancies only. The number of screening tests performed in the eligible population was assessed and the reasons for missed screenings identified with the help of the electronic clinical database. SPSS Statistics 25 and GraphPad version 8.0 for Windows were used for statistical analysis.
Results 6535 pregnancies were included, 4510 (69.0%) of which were screened for PE. The percentage of patients being offered PE screening increased over the years from 63.1 to 96.7% (r s = 0.96; p = 0.003), while the rate of screenings performed in eligible patients remained stable at a median [range] of 86.2% [78.0 - 91.8%] (p = ns). 2025 (31.0%) pregnancies were not screened for PE, 1306 (64.5%) because they were not eligible for screening. 145 (2.2%) women explicitly declined PE screening; their background risk was lower than that of women who accepted screening.
Conclusion Our study shows that integration of PE screening into the routine first trimester ultrasound scan is feasible and widely accepted by pregnant women and health care providers
MicroRNA Function in Human Diseases
MicroRNAs are emerging as a hot topic in research, and rightfully so. They show great promise as targets of treatment and as markers for common human diseases, such as cancer and metabolic diseases. In this review, we address some of the basic questions regarding micro- RNA function in human disease and the clinical significance of microRNAs. Specifically, micro- RNAs in epigenetics, cancer, and metabolic diseases are discussed, with examples taken from cholangiocarcinoma and nonalcoholic fatty liver disease
- …