Clinically Translatable Cell Tracking and Quantification by MRI in Cartilage Repair Using Superparamagnetic Iron Oxides

Background: Articular cartilage has very limited intrinsic regenerative capacity, making cell-based therapy a tempting approach for cartilage repair. Cell tracking can be a major step towards unraveling and improving the repair process of these therapies. We studied superparamagnetic iron oxides (SPIO) for labeling human bone marrow-derived mesenchymal stem cells (hBMSCs) regarding effectivity, cell viability, long term metabolic cell activity, chondrogenic differentiation and hBMSC secretion profile. We additionally examined the capacity of synovial cells to endocytose SPIO from dead, labeled cells, together with the use of magnetic resonance imaging (MRI) for intra-articular visualization and quantification of SPIO labeled cells. Methodology/Prinicipal Findings: Efficacy and various safety aspects of SPIO cell labeling were determined using appropriate assays. Synovial SPIO re-uptake was investigated in vitro by co-labeling cells with SPIO and green fluorescent protein (GFP). MRI experiments were performed on a clinical 3.0T MRI scanner. Two cell-based cartilage repair techniques were mimicked for evaluating MRI traceability of labeled cells: intra-articular cell injection and cell implantation in cartilage defects. Cells were applied ex vivo or in vitro in an intra-articular environment and immediately scanned. SPIO labeling was effective and did not impair any of the studied safety aspects, including hBMSC secretion profile. SPIO from dead, labeled cells could be taken up by synovial cells. Both injected and implanted SPIO-labeled cells could accurately be visualized by MRI in a clinically relevant sized joint model using clinically applied cell doses. Finally, we quantified the amount of labeled cells seeded in cartilage defects using MR-based relaxometry. Conclusions: SPIO labeling appears to be safe without influencing cell behavior. SPIO labeled cells can be visualized in an intra-articular environment and quantified when seeded in cartilage defects.Biomechanical EngineeringMechanical, Maritime and Materials Engineerin

The CARMENES search for exoplanets around M dwarfs High-resolution optical and near-infrared spectroscopy of 324 survey stars

The CARMENES radial velocity (RV) survey is observing 324 M dwarfs to search for any orbiting planets. In this paper, we present the survey sample by publishing one CARMENES spectrum for each M dwarf. These spectra cover the wavelength range 520–1710 nm at a resolution of at least R >80 000, and we measure its RV, Hα emission, and projected rotation velocity. We present an atlas of high-resolution M-dwarf spectra and compare the spectra to atmospheric models. To quantify the RV precision that can be achieved in low-mass stars over the CARMENES wavelength range, we analyze our empirical information on the RV precision from more than 6500 observations. We compare our high-resolution M-dwarf spectra to atmospheric models where we determine the spectroscopic RV information content, Q, and signal-to-noise ratio. We find that for all M-type dwarfs, the highest RV precision can be reached in the wavelength range 700–900 nm. Observations at longer wavelengths are equally precise only at the very latest spectral types (M8 and M9). We demonstrate that in this spectroscopic range, the large amount of absorption features compensates for the intrinsic faintness of an M7 star. To reach an RV precision of 1 m s−1 in very low mass M dwarfs at longer wavelengths likely requires the use of a 10 m class telescope. For spectral types M6 and earlier, the combination of a red visual and a near-infrared spectrograph is ideal to search for low-mass planets and to distinguish between planets and stellar variability. At a 4 m class telescope, an instrument like CARMENES has the potential to push the RV precision well below the typical jitter level of 3–4 m s−1

The CARMENES search for exoplanets around M dwarfs High-resolution optical and near-infrared spectroscopy of 324 survey stars

The CARMENES radial velocity (RV) survey is observing 324 M dwarfs to search for any orbiting planets. In this paper, we present the survey sample by publishing one CARMENES spectrum for each M dwarf. These spectra cover the wavelength range 520–1710 nm at a resolution of at least R >80 000, and we measure its RV, Hα emission, and projected rotation velocity. We present an atlas of high-resolution M-dwarf spectra and compare the spectra to atmospheric models. To quantify the RV precision that can be achieved in low-mass stars over the CARMENES wavelength range, we analyze our empirical information on the RV precision from more than 6500 observations. We compare our high-resolution M-dwarf spectra to atmospheric models where we determine the spectroscopic RV information content, Q, and signal-to-noise ratio. We find that for all M-type dwarfs, the highest RV precision can be reached in the wavelength range 700–900 nm. Observations at longer wavelengths are equally precise only at the very latest spectral types (M8 and M9). We demonstrate that in this spectroscopic range, the large amount of absorption features compensates for the intrinsic faintness of an M7 star. To reach an RV precision of 1 m s−1 in very low mass M dwarfs at longer wavelengths likely requires the use of a 10 m class telescope. For spectral types M6 and earlier, the combination of a red visual and a near-infrared spectrograph is ideal to search for low-mass planets and to distinguish between planets and stellar variability. At a 4 m class telescope, an instrument like CARMENES has the potential to push the RV precision well below the typical jitter level of 3–4 m s−1

The CARMENES search for exoplanets around M dwarfs HD147379 b: A nearby Neptune in the temperate zone of an early-M dwarf

We report on the first star discovered to host a planet detected by radial velocity (RV) observations obtained within the CARMENES survey for exoplanets around M dwarfs. HD 147379 (V = 8.9 mag, M = 0.58 ± 0.08 M⊙), a bright M0.0 V star at a distance of 10.7 pc, is found to undergo periodic RV variations with a semi-amplitude of K = 5.1 ± 0.4 m s−1 and a period of P = 86.54 ± 0.06 d. The RV signal is found in our CARMENES data, which were taken between 2016 and 2017, and is supported by HIRES/Keck observations that were obtained since 2000. The RV variations are interpreted as resulting from a planet of minimum mass mP sin i = 25 ± 2 M⊕, 1.5 times the mass of Neptune, with an orbital semi-major axis a = 0.32 au and low eccentricity (e < 0.13). HD 147379 b is orbiting inside the temperate zone around the star, where water could exist in liquid form. The RV time-series and various spectroscopic indicators show additional hints of variations at an approximate period of 21.1 d (and its first harmonic), which we attribute to the rotation period of the star.FEDER/ERF FICTS-2011-02 fundsMajor Research Instrumentation Programme and DFG Research Unit FOR2544 “Blue Planets around Red StarsEuropean Research Council (ERC-279347), Deutsche Forschungsgemeinschaft (RE 1664/12-1, RE 2694/4-1), Bundesministerium für Bildung und Forschung (BMBF-05A14MG3, BMBF-05A17MG3), Spanish Ministry of Economy and Competitiveness (MINECO, grants AYA2015-68012-C2-2-P, AYA2016-79425-C3-1,2,3-P, AYA2015-69350-C3-2-P, AYA2014-54348-C03- 01, AYA2014-56359-P, AYA2014-54348-C3-2-R, AYA2016-79425-C3-3-P and 2013 Ramòn y Cajal program RYC-2013-14875), Fondo Europeo de Desarrollo Regional (FEDER, grant ESP2016-80435-C2-1-R, ESP2015-65712-C5- 5-R), Generalitat de Catalunya/CERCA programme, Spanish Ministerio de Educación, Cultura y Deporte, programa de Formación de Profesorado Universitario (grant FPU15/01476), Deutsches Zentrum für Luft- und Raumfahrt (grants 50OW0204 and 50OO1501), Office of Naval Research Global (award no. N62909-15-1-2011), Mexican CONACyT grant CB-2012-183007

The CARMENES search for exoplanets around M dwarfs. First visual-channel radial-velocity measurements and orbital parameter updates of seven M-dwarf planetary systems

Stars and planetary system

CARMENES: high-resolution spectra and precise radial velocities in the red and infrared

SPIE Astronomical Telescopes + Instrumentation (2018, Austin, Texas, United States

Understanding academic performance of international students: The role of ethnicity, academic and social integration

More than 3 million students study outside their home country, primarily at a Western university. A common belief among educators is that international students are insufficiently adjusted to higher education in their host country, both academically and socially. Furthermore, several groups of international students experience considerable amounts of stress while adapting to the culture of the host-institute. Several researchers argue that studies on adaptation of international students should widen its focus to the underlying mechanisms that leads towards this “misalignment”. In a cross-institutional comparison among 958 students at five business schools in the Netherlands, differences in academic performance between local and international students were identified by focussing on their levels of academic and social integration. Students’ academic integration was measured with the Students’ Adaptation to College Questionnaire (SACQ), while students’ social integration was measured with a newly developed and validated questionnaire. The results indicate that the degree of academic success of international students is multi-faceted. International students with a (mixed) western ethnic background perform well on both academic and social integration, and also attained higher study-performance in comparison to domestic students. In contrast, international students with a non-Western background are less integrated compared to other international students. Nevertheless, they have a similar study-performance. Finally, academic adjustment is the main predictor of study-performance for Dutch, Western and Mixed-Western students. Social adjustment was negatively related to study-performance. The lack of fit for predicting long-term study success of non-Western students indicates that their academic and social integration processes are more complex and non-linear

Academic and social integration of international and local students at five business schools, a cross-institutional comparison

An increasing number of students choose to study at a university in a foreign country. A common belief among educators is that international students are insufficiently academically adjusted. Recent research has found a mixed picture on whether international students underperform in academic integration and academic performance. Therefore, Morrison et al. (2005) argue that research should extend its focus to understanding the underlying reasons for these performance differences of international versus local students.In a cross-institutional comparison among 871 students of five business schools, we investigated the differences in academic and social integration amongst local and international students. International students value their faculty and educational system more than local students. However, international and local students have limited social contact with each other and spend their private time differently. Finally, students with a non-Western background are less integrated than Western students, have considerable lower academic and social integration scores and have (marginally) lower grade point average (GPA) and European credit transfer system (ECTS) scores. Institutes with small classes and collaborative learning settings seem to provide a more favourable learning environment for international students

Scholastic Achievement: A Multivariate Analysis of Nutritional, Intellectual, Socioeconomic, Sociocultural, Familial, and Demographic Variables in Chilean School-Age Children

Artículo de publicación ISI.OBJECTIVE: We determined relative effects of nutritional status, intellectual ability, exposure to mass media, and socioeconomic, sociocultural, familial, demographic, and educational variables on scholastic achievement (SA). METHODS: This was a cross-sectional study. Exposure to mass media and nutritional, intellectual, socioeconomic, sociocultural, familial, demographic, and educational factors, including approximately 2000 variables, were measured in a representative and proportional sample of 4509 school-age children from elementary and high schools in Chile's Metropolitan Region. The field study was carried out between 1986 and 1987, and data processing, which lasted 15 y, was completed in 2002. RESULTS: Within the total sample, intellectual ability, level of maternal schooling, head circumference-for-age Z score, book reading, in-door plumbing, level of paternal schooling, type of school, quality of housing, height-for-age Z score, and calcium intake were the independent variables with the greatest explanatory power in SA variance (r(2) = 0.508). In most grades, IA was the independent variable with the greatest explanatory power in SA variance. In adolescents in their fourth year of high school and whose physical growth and intellectual development processes are consolidated, intellectual ability, age, head circumference-for-age Z score, book reading, type of school, and level of paternal schooling were the independent variables with the greatest explanatory power in SA variance (r(2) = 0.60). CONCLUSIONS: These findings show that SA is conditioned by multiple factors depending on the characteristics of school-age children, their families, and the educational system. Nutritional indicators of past nutrition are significantly associated with SA, especially head circumference-for-age Z score. This information may be useful for health and educational planning.This study was supported in part by grants 1841167 and 1880818 from the National Fund for Scientific and Technologic Development and grant S 2169-924F from the Research and Development Department, University of Chile