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Characterization of how the microenvironment, or niche, regulates stem cell activity is central to understanding stem cell biology and to developing strategies for the therapeutic manipulation of stem cells. Low oxygen tension (hypoxia) is commonly thought to be a shared niche characteristic in maintaining quiescence in multiple stem cell types. However, support for the existence of a hypoxic niche has largely come from indirect evidence such as proteomic analysis, expression of hypoxia inducible factor-1α (Hif-1α) and related genes, and staining with surrogate hypoxic markers (for example, pimonidazole). Here we perform direct in vivo measurements of local oxygen tension (pO2) in the bone marrow of live mice. Using two-photon phosphorescence lifetime microscopy, we determined the absolute pO2 of the bone marrow to be quite low (

Significance: Raman spectroscopy is a valuable technique for tissue identification, but its conventional implementation is hindered by low efficiency due to scattering. Addressing this limitation, we are further developing the wavelength-swept Raman spectroscopy approach. Aim: We aim to enhance Raman signal detection by employing a laser capable of sweeping over a wide wavelength range to sequentially excite tissue with different wavelengths, paired with a photodetector featuring a fixed narrow-bandpass filter for collecting the Raman signal at a specific wavelength. Approach: We experimentally validate our technique using a fiber-based swept-source Raman spectroscopy setup. In addition, simulations are conducted to assess the efficacy of our approach in comparison with conventional spectrometer-based Raman spectroscopy. Results: Our simulations reveal that the wavelength-swept configuration leads to a significantly stronger signal compared with conventional spectrometer-based Raman spectroscopy. Experimentally, our setup demonstrates an improvement of at least 200x in photon detection compared with the spectrometer-based setup. Furthermore, data acquired from different regions of a fixed monkey brain using our technique achieves 99% accuracy in classification via k-nearest neighbor analysis. Conclusions: Our study showcases the potential of wavelength-swept Raman spectroscopy for tissue identification, particularly in highly scattering media, such as the brain. The developed technique offers enhanced signal detection capabilities, paving the way for future in vivo applications in tissue characterization. [ABSTRACT FROM AUTHOR]

Occupational health and safety (OHS) is a largely technical field, still guided by a biomedical model of health that seeks to isolate factors that cause injury. Despite a growing literature on organisational and managerial factors influencing occupational health, their full integration into the OHS concept has been slow. A broader understanding is still needed to recognise the restructuring of work and the link between well-being at work and management style. In the context of a rapidly changing world of work, increasing workforce diversity, and inequality, OHS needs to take account of the social sciences and humanities to broaden its reductionist vision. Occupational illnesses, distress, and suffering, especially in relation to relational or organisational issues, have no initial cause or specific ontology; they result from a long-standing process or repetitive relational pattern that needs to be exposed and understood in greater depth, considering contextual factors and dynamics. Using the authors' anthropological backgrounds and the basic principles of the double bind theory developed many decades ago by Gregory Bateson and his colleagues at the Palo Alto School of Communication, we propose a reflection on pragmatic paradoxes or double bind situations in the workplace (which can be briefly defined as the presence of contradictory or conflicting demands or messages), their potential impact on workers' health and well-being, and how to resolve them. This paper sought to explore the world of pragmatic paradoxes and double binds by discussing different categories, types, or forms of paradoxes/double binds that occur in the context of occupational health and their underlying mechanisms. It also includes a discussion of the possible link to the concept of super-diversity, as it too is associated with migration channels, employment, gendered flows, and local systems. Finally, we discuss the practical implications of this understanding for health professionals, researchers, and policymakers, from a perspective of promoting more holistic and context-sensitive interactional approaches to occupational health. [ABSTRACT FROM AUTHOR]

This paper presents results of a study conducted with undergraduate students involved in either problem- or project-based curricula (Medicine and Engineering, respectively) at the Université de Sherbrooke, Canada. The objective of the present research was to measure the impact of these innovative curricula on students' engagement and persistence in higher education. Our research question was: What determinants better predict students' engagement and persistence in innovative curricula such as PBL? Nine variables were examined as potential predictors of both factors (engagement and persistence). Results showed a variation in variables predicting engagement and persistence, with the most significant predictor being stress related.