Optical force-induced nonlinearity and self-guiding of light in human red blood cell suspensions

Osmotic conditions play an important role in the cell properties of human red blood cells (RBCs), which are crucial for the pathological analysis of some blood diseases such as malaria. Over the past decades, numerous efforts have mainly focused on the study of the RBC biomechanical properties that arise from the unique deformability of erythrocytes. Here, we demonstrate nonlinear optical effects from human RBCs suspended in different osmotic solutions. Specifically, we observe self-trapping and scattering-resistant nonlinear propagation of a laser beam through RBC suspensions under all three osmotic conditions, where the strength of the optical nonlinearity increases with osmotic pressure on the cells. This tunable nonlinearity is attributed to optical forces, particularly the forward scattering and gradient forces. Interestingly, in aged blood samples (with lysed cells), a notably different nonlinear behavior is observed due to the presence of free hemoglobin. We use a theoretical model with an optical force-mediated nonlocal nonlinearity to explain the experimental observations. Our work on light self-guiding through scattering bio-soft-matter may introduce new photonic tools for noninvasive biomedical imaging and medical diagnosis.Comment: 20 Pages, 5 figures, accepted for publication in Light, Science & Applicatio

Testing breast cancer serum biomarkers for early detection and prognosis in pre-diagnosis samples

This research was funded by the National Institute for Health Research (NIHR) University College London Hospitals (UCLH) Biomedical Research Centre. UKCTOCS was core funded by the Medical Research Council, Cancer Research UK, and the Department of Health with additional support from the Eve Appeal, Special Trustees of Bart’s and the London, and Special Trustees of UCLH. OB and JFT also received support from the Eve Appeal Gynaecological Cancer Research Trust and Cancer Research UK PRC Programme Grant A12677

Ergonomic audit at university

This thesis deals with ergonomic audit of the workspace and working conditions of a university. First, factors affecting students and researchers are analyzed, with focus on their effects on physical and mental health. Attention is mainly given to the effects of thermal and moisture parameter of air, carbon dioxide concentration, lighting and classroom and office equipment. Level of adaptation of the workspace to the needs of disabled students and faculty is also considered. In the practical part of the thesis, the proposed audit is carried out at the Faculty of Mechanical Engineering of the Brno University of Technology. Measurements of ergonomic parameters were performed in selected rooms. Based on their results, shortcomings were identified and corrective measures were proposed

SARS-Cov2 acute and post-active infection in the context of autoimmune and chronic inflammatory diseases

International audienceThe clinical and immunological spectrum of acute and post-active COVID-19 syndrome overlaps with criteria used to characterize autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Indeed, following SARS-Cov2 infection, the innate immune response is altered with an initial delayed production of interferon type I (IFN-I), while the NF-kappa B and inflammasome pathways are activated. In lung and digestive tissues, an alternative and extrafollicular immune response against SARS-Cov2 takes place with, consequently, an altered humoral and memory T cell response leading to breakdown of tolerance with the emergence of autoantibodies. However, the risk of developing severe COVID-19 among SLE and RA patients did not exceed the general population except in those having pre-existing neutralizing autoantibodies against IFN-I. Treatment discontinuation rather than COVID-19 infection or vaccination increases the risk of developing flares. Last but not least, a limited number of case reports of individuals having developed SLE or RA following COVID-19 infection/vaccination have been reported. Altogether, the SARS-Cov2 pandemic represents an unique opportunity to investigate the dangerous interplay between the immune response against infectious agents and autoimmunity, and to better understand the triggering role of infection as a risk factor in autoimmune and chronic inflammatory disease development

Interplay of Environmental, Individual and Genetic Factors in Rheumatoid Arthritis Provocation

In this review, we explore systemization of knowledge about the triggering effects of non-genetic factors in pathogenic mechanisms that contribute to the development of rheumatoid arthritis (RA). Possible mechanisms involving environmental and individual factors in RA pathogenesis were analyzed, namely, infections, mental stress, sleep deprivation ecology, age, perinatal and gender factors, eating habits, obesity and smoking. The non-genetic factors modulate basic processes in the body with the impact of these factors being non-specific, but these common challenges may be decisive for advancement of the disease in the predisposed body at risk for RA. The provocation of this particular disease is associated with the presence of congenital loci minoris resistentia. The more frequent non-genetic factors form tangles of interdependent relationships and, thereby, several interdependent external factors hit one vulnerable basic process at once, either provoking or reinforcing each other. Understanding the specific mechanisms by which environmental and individual factors impact an individual under RA risk in the preclinical stages can contribute to early disease diagnosis and, if the factor is modifiable, might be useful for the prevention or delay of its development

Humor From The Perspective Of Positive Psychology. Implications For Research On Development In Adulthood

The purpose of the article is the presentation of the ways that humor was understood within the current of positive psychology; the state and advances of research on the significance of this property in achieving and safeguarding a "good life” as well as the legitimacy and possibility of applying the theoretical and research approach devised by the mentioned orientation approaches to issues connected with humor to the field of developmental psychology during the life course. A conceptualisation of humor was presented as a character strength comprising the virtue of transcendence in the approach of Peterson and Seligman, a composite of wisdom in the concept of Webster and of a thinking style, experiencing and action in the theory of Martin. A review of research was then undertaken: humor as a virtue imbuing property; humor correlates understood from the perspective of positive psychology; manifestations of its regulative role and individual differences in humor as a resource contributing to individual growth. In the closing paragraphs a suggestion was formulated regarding humor research as a resource that supports positive development, namely, the fulfilment of developmental tasks, overcoming developmental crises and coping with problems connected with ageing

Optical force-induced nonlinearity and self-guiding of light in human red blood cell suspensions.

Osmotic conditions play an important role in the cell properties of human red blood cells (RBCs), which are crucial for the pathological analysis of some blood diseases such as malaria. Over the past decades, numerous efforts have mainly focused on the study of the RBC biomechanical properties that arise from the unique deformability of erythrocytes. Here, we demonstrate nonlinear optical effects from human RBCs suspended in different osmotic solutions. Specifically, we observe self-trapping and scattering-resistant nonlinear propagation of a laser beam through RBC suspensions under all three osmotic conditions, where the strength of the optical nonlinearity increases with osmotic pressure on the cells. This tunable nonlinearity is attributed to optical forces, particularly the forward-scattering and gradient forces. Interestingly, in aged blood samples (with lysed cells), a notably different nonlinear behavior is observed due to the presence of free hemoglobin. We use a theoretical model with an optical force-mediated nonlocal nonlinearity to explain the experimental observations. Our work on light self-guiding through scattering bio-soft-matter may introduce new photonic tools for noninvasive biomedical imaging and medical diagnosis