Characterization of nanomedicines’ surface coverage using molecular probes and capillary electrophoresis

International audienceA faithful characterization of nanomedicine (NM) is needed for a better understanding of their in vivo outcomes. Size and surface charge are studied with well-established methods. However, other relevant parameters for the understanding of NM behavior in vivo remain largely inaccessible. For instance, the reactive surface of nanomedicines, which are often grafted with macromolecules to decrease their recognition by the immune system, is excluded from a systematic characterization. Yet, it is known that a subtle modification of NMs' surface characteristics (grafting density, molecular architecture and conformation of macromolecules) is at the root of major changes in the presence of biological components. In this work, a method that investigates the steric hindrance properties of the NMs’ surface coverage based on its capacity to exclude or allow adsorption of well-defined proteins was developed based on capillary electrophoresis. A series of proteins with different molecular weights (MW) were used as molecular probes to screen their adsorption behavior on nanoparticles bearing different molecular architectures at their surface. This novel strategy evaluating to some degree a functionality of NMs can bring additional information about their shell property and might allow for a better perception of their behavior in the presence of biological components. The developed method could discriminate nanoparticles with a high surface coverage excluding high MW proteins from nanoparticles with a low surface coverage that allowed high MW proteins to adsorb on their surface. The method has the potential for further standardization and automation for a routine use. It can be applied in quality control of NMs and to investigate interactions between proteins and NM in different situations

iSTAR first light: Characterizing astronomy education research dissertations in the iSTAR database

There is widespread interest among discipline-based science education researchers to situate their research in the existing scholarly literature base. Unfortunately, traditional approaches to conducting a thorough literature review are unduly hindered in astronomy education research as the venues in which scholarship is reported are fragmented and widely dispersed across journals of varying disciplines. The international STudies of Astronomy education Research (iSTAR) online repository is the result of a concerted international community effort to collect and categorize existing research from peer-reviewed journal articles, dissertations/theses, and grey literature. In a “first light” survey of over 300 U.S. dissertations, we find: (i) work in AER dates back to 1923; (ii) the number of extant dissertations is far greater than anticipated; (iii) research methods definitions have evolved; and (iv) most work has studied participants’ broad knowledge rather than specific learning targets. The surprisingly wide breadth of rarely cited research motivates us to collect more AER from across international and cross-disciplinary sources

Measuring the positive psychological well-being of people with rheumatoid arthritis: a cross-sectional validation of the subjective vitality scale

Introduction: People with rheumatoid arthritis (RA) frequently suffer from compromised physical and psychological health, however, little is known about positive indicators of health, due to a lack of validated outcome measures. This study aims to validate a clinically relevant outcome measure of positive psychological well-being for people with RA. The first study examined the reliability and factorial validity of the Subjective Vitality Scale (SVS), whilst study 2 tested the instruments convergent validity. Methods: In study 1, National Rheumatoid Arthritis Society members (N = 333; M age = 59.82 years SD = 11.00) completed a postal questionnaire. For study 2, participants (N = 106; M age = 56 years, SD = 12 years) were those recruited to a randomized control trial comparing two physical activity interventions who completed a range of health-related questionnaires. Results: The SVS had a high level of internal consistency (α = .93, Rho = .92). Confirmatory factor analysis supported the uni-dimensional factor structure of the questionnaire among RA patients [χ = 1327 (10), CFI = 1.0, SRMSR = .01 and RMSEA = .00 (.00 - .08)]. Support for the scales convergent validity was revealed by significant (p < .05) relationships, in expected directions, with health related quality of life (r = .59), physical function (r = .58), feelings of fatigue (r = −.70), anxiety (r = −.57) and depression (r = −.73). Conclusions: Results from two studies have provided support for the internal consistency, factorial structure and convergent validity of the Subjective Vitality Scale. Researchers and healthcare providers may employ this clinically relevant, freely available and brief assessment with the confidence that it is a valid and reliable measure of positive psychological well-being for RA patients

Unlocking preservation bias in the amber insect fossil record through experimental decay.

Fossils entombed in amber are a unique resource for reconstructing forest ecosystems, and resolving relationships of modern taxa. Such fossils are famous for their perfect, life-like appearance. However, preservation quality is vast with many sites showing only cuticular preservation, or no fossils. The taphonomic processes that control this range are largely unknown; as such, we know little about potential bias in this important record. Here we employ actualistic experiments, using, fruit flies and modern tree resin to determine whether resin type, gut microbiota, and dehydration prior to entombment affects decay. We used solid phase microextraction gas chromatography-mass spectrometry (SPME GC-MS) to confirm distinct tree resin chemistry; gut microbiota of flies was modified using antibiotics and categorized though sequencing. Decay was assessed using phase contrast synchrotron tomography. Resin type demonstrates a significant control on decay rate. The composition of the gut microbiota was also influential, with minor changes in composition affecting decay rate. Dehydration prior to entombment, contrary to expectations, enhanced decay. Our analyses show that there is potential significant bias in the amber fossil record, especially between sites with different resin types where ecological completeness and preservational fidelity are likely affected

Analysis on the situation of subjective well-being and its influencing factors in patients with ankylosing spondylitis

BACKGROUND: To examine the subjective well-being (SWB) in patients with ankylosing spondylitis (AS) compared with the healthy controls, and to explore the associations between SWB and demographic characteristics, disease-specific variables in AS patients. METHODS: SWB was assessed with General Well-Being Schedule (GWBS) in 200 AS patients and 210 healthy controls. Comparisons among subgroups were performed to investigate how certain aspects operate as favorable or adverse factors in influencing SWB in the patients with AS. RESULTS: Both men and women with AS reported significantly impaired SWB on all scales of the GWBS except for the Control (O) scale. The results revealed that better sleep, lower disease activity and more family care predicted higher SWB. In AS patients, positive attitude towards therapy prospect was significantly associated with higher SWB. Therapy prospect refers to the hope of patients about the disease treatment. CONCLUSIONS: Compared with general population, SWB might be affected by the onset of AS. There are significant associations between SWB and sleep quality, BASDAI, APGAR, therapy prospect

Evaluation of zeta potential of nanomaterials by electrophoretic light scattering: Fast field reversal versus Slow field reversal modes

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