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Psychological aspects of labor and birth have received little attention within maternity care service planning or clinical practice. The aim of this paper is to propose a model demonstrating how neurohormonal processes, in particular oxytocinergic mechanisms, not only control the physiological aspects of labor and birth, but also contribute to the subjective psychological experiences of birth. In addition, sensory information from the uterus as well as the external environment might influence these neurohormonal processes thereby influencing the progress of labor and the experience of birth. In this new model of childbirth, we integrated the findings from two previous systematic reviews, one on maternal plasma levels of oxytocin during physiological childbirth and one meta-synthesis of women´s subjective experiences of physiological childbirth. The neurobiological processes induced by the release of endogenous oxytocin during birth influence maternal behaviour and feelings in connection with birth in order to facilitate birth. The psychological experiences during birth may promote an optimal transition to motherhood. The spontaneous altered state of consciousness, that some women experience, may well be a hallmark of physiological childbirth in humans. The data also highlights the crucial role of one-to-one support during labor and birth. The physiological importance of social support to reduce labor stress and pain necessitates a reconsideration of many aspects of modern maternity care. By listening to women's experiences and by observing women during childbirth, factors that contribute to an optimized process of labor, such as the mothers' wellbeing and feelings of safety, may be identified. These observations support the integrative role of endogenous oxytocin in coordinating the neuroendocrine, psychological and physiological aspects of labor and birth, including oxytocin mediated. decrease of pain, fear and stress, support the need for midwifery one-to-one support in labour as well as the need for maternity care that optimizes the function of these neuroendocrine processes even when birth interventions are used. Women and their partners would benefit from understanding the crucial role that endogenous oxytocin plays in the psychological and neuroendocrinological process of labor.

Main conclusion The starch–statolith theory was established science for a century when the existence of gravitropic, starchless mutants questioned its premise. However, detailed kinetic studies support a statolith-based mechanism for graviperception. Gravitropism is the directed growth of plants in response to gravity, and the starch–statolith hypothesis has had a consensus among scientists as the accepted model for gravity perception. However, in the late 1980s, with the isolation of a starchless mutant (lacking phosphoglucomutase, pgm) of Arabidopsis thaliana that was gravitropic, a statolith-based hypothesis for graviperception was questioned. Two groups studied the physiology and gravitropism kinetics of this pgm mutant, and these papers were published side-by-side in Planta . Based on the observation that the starchless mutant was responsive to gravity, Tim Caspar and colleagues (Caspar and Pickard, Planta 177:185–197, 1989) suggested that their results negated the starch–statolith hypothesis. In contrast, John Z. Kiss (Kiss et al., Planta 177:198–206, 1989) and colleagues turned the argument around 180 degrees and concluded that since a full complement of starch is required for full gravitropic sensitivity, in fact, their pgm studies provided strong support for a statolith-based model for gravity perception. Kiss and coworkers also provided evidence that the starchless plastids were relatively dense and proposed that these organelles function as statoliths in the pgm mutant plants. These two publications stimulated novel approaches (e.g., magnetophoresis, optical tweezers, spaceflight experiments, and laser ablation) to the study of gravity perception in plants. The controversy regarding the starch–statolith hypothesis remained for about a decade or so, but the current consensus supports a statolith-based model for graviperception in plants.

The state of isolation and confinement causes several symptoms as a psycho-physiological stressor. The crew’s health and condition may play a crucial role in prolonged space sojourns success. However, it’s important to distinguish the role of microgravity from the distress aspect to better understand human physiology in training during space missions. Although stabilography is a commonly used biomechanical technique, there is not enough data on the measurement repeatability. It has already been proven that the stabilograms differ between subjects due to multiple anatomical and physiological characteristics but the intersubject variability remains unclear. The study provides statistical data on 10 different stabilography measurements of 18 participants performed on different days during an analog space mission (5 females and 4 males) and in normal conditions (5 females and 4 males). Descriptive statistics and interclass correlation were used to determine intra- and intersubject variability. Mann-Whitney test was used for group comparison. Isolation was found to significantly impact symmetry and forefoot/backfoot index in trials with eyes open and ellipse area and forefoot/backfoot index in trials with eyes closed. The results show a diverse level of stabilography parameters measurement repeatability. The least stable parameter was the ellipse area (%SD = 45.79 %) and the most stable stance symmetry (%SD = 4.60 %). The results confirm ellipse area and center of pressure path poor repeatability and relative stability of parameters describing load distribution. It also proves the importance of performing multiple trials in stabilography studies to reduce the risk of erroneous results caused by intersubject variability.

Despite the use of countermeasures (including intense physical activity), cosmonauts and astronauts develop muscle atony and atrophy, cardiovascular system failure, osteopenia, etc. All these changes, reminiscent of age-related physiological changes, occur in a healthy person in microgravity quite quickly – within a few months. Adaptation to the lost of gravity leads to the symptoms of aging, which are compensated after returning to Earth. The prospect of interplanetary flights raises the question of gravity thresholds, below which the main physiological systems will decrease their functional potential, similar to aging, and affect life expectancy. An important role in the aging process belongs to the body’s cellular reserve – progenitor cells, which are involved in physiological remodeling and regenerative/reparative processes of all physiological systems. With age, progenitor cell count and their regenerative potential decreases. Moreover, their paracrine profile becomes pro-inflammatory during replicative senescence, disrupting tissue homeostasis. Mesenchymal stem/stromal cells (MSCs) are mechanosensitive, and therefore deprivation of gravitational stimulus causes serious changes in their functional status. The review compares the cellular effects of microgravity and changes developing in senescent cells, including stromal precursors.

Modification of physiological processes may be used to offset the negative effects of gravity on plant growth and development. This study was set up to assess the efficacy of sodium nitroprusside (SNP) and indole-3-acetic acid (IAA) in improving the germination characteristics of Oryza sativa var. Nerica in microgravity. The seeds were primed with SNP and IAA solutions, which were then divided into three concentrations: 100, 500, and 1000 mg/L. The primed rice seeds were then inoculated and mounted on the Clinostat at 2 rpm for 168 h. Under microgravity, the germination of rice was found to be impaired. However, germination was increased when IAA and SNP were used under the simulated microgravity conditions. For instance, seedlings exposed to 100 ppm IAA had at least 10% germination within the first 48 h and 100% germination within the first 120 h. Also, seedlings treated with 100 ppm SNP under microgravity showed a significantly improved germination response with 40% germination occurring within 48 h and 100% germination occurring within the first 72 h. Although microgravity caused an initial 83-h delay in germination, this was reduced to less than 45 h when seeds were pretreated with 100 ppm IAA and SNP. Regardless of the chemical agent used as the growth-stimulating component, there was more variation with germination time than with apparent changes in results induced by treatment concentrations. The study also reinforces the importance of chlorophyll to plant productivity because of the effects of the treatments on chlorophyll concentration, especially IAA. Moreover, the use of IAA and SNP is a promising strategy for mitigating the negative physiological effects of microgravity.

Teleost fish such as zebrafish (Danio rerio) are increasingly used for physiological, genetic and developmental studies. Our understanding of the physiological consequences of altered gravity in an entire organism is still incomplete. We used altered gravity and drug treatment experiments to evaluate their effects specifically on bone formation and more generally on whole genome gene expression. By combining morphometric tools with an objective scoring system for the state of development for each element in the head skeleton and specific gene expression analysis, we confirmed and characterized in detail the decrease or increase of bone formation caused by a 5 day treatment (from 5dpf to 10 dpf) of, respectively parathyroid hormone (PTH) or vitamin D3 (VitD3). Microarray transcriptome analysis after 24 hours treatment reveals a general effect on physiology upon VitD3 treatment, while PTH causes more specifically developmental effects. Hypergravity (3g from 5dpf to 9 dpf) exposure results in a significantly larger head and a significant increase in bone formation for a subset of the cranial bones. Gene expression analysis after 24 hrs at 3g revealed differential expression of genes involved in the development and function of the skeletal, muscular, nervous, endocrine and cardiovascular systems. Finally, we propose a novel type of experimental approach, the \"Reduced Gravity Paradigm\", by keeping the developing larvae at 3g hypergravity for the first 5 days before returning them to 1g for one additional day. 5 days exposure to 3g during these early stages also caused increased bone formation, while gene expression analysis revealed a central network of regulatory genes (hes5, sox10, lgals3bp, egr1, edn1, fos, fosb, klf2, gadd45ba and socs3a) whose expression was consistently affected by the transition from hyper- to normal gravity.

Microgravity exposure causes several physiological and psychosocial alterations that challenge astronauts’ health during space flight. Notably, many of these changes are mostly related to physical inactivity influencing different functional systems and organ biology, in particular the musculoskeletal system, dramatically resulting in aging-like phenotypes, such as those occurring in older persons on Earth. In this sense, sarcopenia, a syndrome characterized by the loss in muscle mass and strength due to skeletal muscle unloading, is undoubtedly one of the most critical aging-like adverse effects of microgravity and a prevalent problem in the geriatric population, still awaiting effective countermeasures. Therefore, there is an urgent demand to identify clinically relevant biological markers and to underline molecular mechanisms behind these effects that are still poorly understood. From this perspective, a lesson from Geroscience may help tailor interventions to counteract the adverse effects of microgravity. For instance, decades of studies in the field have demonstrated that in the older people, the clinical picture of sarcopenia remarkably overlaps (from a clinical and biological point of view) with that of frailty, primarily when referred to the physical function domain. Based on this premise, here we provide a deeper understanding of the biological mechanisms of sarcopenia and frailty, which in aging are often considered together, and how these converge with those observed in astronauts after space flight.

Both nationally and internationally, midwives' practices during the second stage of labour vary. A midwife's practice can be influenced by education and cultural practices but ultimately it should be informed by up-to-date scientific evidence. We conducted a systematic review of the literature to retrieve evidence that supports high quality intrapartum care during the second stage of labour. A systematic literature search was performed to September 2019 in collaboration with a medical information specialist. Bibliographic databases searched included: PubMed, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, Maternity and Infant Care Database and The Cochrane Library, resulting in 6,382 references to be screened after duplicates were removed. Articles were then assessed for quality by two independent researchers and data extracted. 17 studies focusing on midwives' practices during physiological second stage of labour were included. Two studies surveyed midwives regarding their practice and one study utilising focus groups explored how midwives facilitate women's birthing positions, while another focus group study explored expert midwives' views of their practice of preserving an intact perineum during physiological birth. The remainder of the included studies were primarily intervention studies, highlighting aspects of midwifery practice during the second stage of labour. The empirical findings were synthesised into four main themes namely: birthing positions, non-pharmacological pain relief, pushing techniques and optimising perineal outcomes; the results were outlined and discussed. By implementing this evidence midwives may enable women during the second stage of labour to optimise physiological processes to give birth. There is, however, a dearth of evidence relating to midwives' practice, which provides a positive experience for women during the second stage of labour. Perhaps this is because not all midwives' practices during the second stage of labour are researched and documented. This systematic review provides a valuable insight of the empirical evidence relating to midwifery practice during the physiological second stage of labour, which can also inform education and future research. The majority of the authors were members of the EU COST Action IS1405: Building Intrapartum Research Through Health (BIRTH). The study protocol is registered in the International Prospective Register of Systematic Reviews (PROSPERO; Registration CRD42018088300) and is published (Verhoeven, Spence, Nyman, Otten, Healy, 2019).

Gravity is one of the most ubiquitous environmental effects on living systems: Cellular and organismal responses to gravity are of central importance to understanding the physiological function of organisms, especially eukaryotes. Gravity has been demonstrated to have strong effects on the closed cardiovascular systems of terrestrial vertebrates, with rapidly responding neural reflexes ensuring proper blood flow despite changes in posture. Invertebrates possess open circulatory systems, which could provide fewer mechanisms to restrict gravity effects on blood flow, suggesting that these species also experience effects of gravity on blood pressure and distribution. However, whether gravity affects the open circulatory systems of invertebrates is unknown, partly due to technical measurement issues associated with small body size. Here we used X-ray imaging, radio-tracing of hemolymph, and micro-pressure measurements in the American grasshopper, Schistocerca americana, to assess responses to body orientation. Our results show that during changes in body orientation, gravity causes large changes in blood and air distribution, and that body position affects ventilation rate. Remarkably, we also found that insects show similar heart rate responses to body position as vertebrates, and contrasting with the classic understanding of open circulatory systems, have flexible valving systems between thorax and abdomen that can separate pressures. Gravitational effects on invertebrate cardiovascular and respiratory systems are likely to be widely distributed among invertebrates and to have broad influence on morphological and physiological evolution.

Recent years have seen the development of multiple in silico lung models, notably with the aim of improving patient care for pulmonary diseases. These models vary in complexity and typically only consider the implementation of pleural pressure, a depression that keeps the lungs inflated. Gravity, often considered negligible compared to pleural pressure, has been largely overlooked, also due to the complexity of formulating physiological boundary conditions to counterbalance it. However, gravity is known to affect pulmonary functions, such as ventilation. In this study, we incorporated gravity into a recent lung poromechanical model. To do so, in addition to the gravitational body force, we proposed novel boundary conditions consisting in a heterogeneous pleural pressure field constrained to counterbalance gravity to reach global equilibrium of applied forces. We assessed the impact of gravity on the global and local behavior of the model, including the pressure–volume response and porosity field. Our findings reveal that gravity, despite being small, influences lung response. Specifically, the inclusion of gravity in our model led to the emergence of heterogeneities in deformation and stress distribution, compatible with in vivo imaging data. This could provide valuable insights for predicting the progression of certain pulmonary diseases by correlating areas subjected to higher deformation and stresses with disease evolution patterns.