Graduated Stress Exposure of Spaceflight Hazards in a Virtual Environment

Stress experienced by astronauts during high-level hazardous situations may poses risk to personnel wellbeing and to mission success. Stress inoculation training (SIT) provides individuals with experience of minor stressors and coping skills during non-critical times to enhance their resistance to stress. This study evaluates the effect of exposure to a low level stressor on physiological response and cognitive load in high level stressor setting. Simulation of fire emergency on the International Space Station (ISS) in a full-scale, immersive, interactive, 3D virtual reality environment facilitated a process for stress inoculation. The experimental settings included two groups that have been exposed to either virtual no-smoke or to virtual light-smoke conditions. The two groups then experienced a subsequent stress exposure in a later trail to heavy-smoke conditions. Physiological responses and cognitive load measure were collected during the trials. The results indicated weak differences in physiological responses between the two groups, in the heavy smoke conditions. Overall, no significant differences have been detected on cognitive load categories according to NASA TLX

The creation of new rotation arc to the rat latissimus dorsi musculo-cutaneous flap with delay procedures

BACKGROUND: Latissimus dorsi musculocutaneous flap is one of the most frequently performed reconstructive techniques in surgery. Latissimus dorsi muscle has two arcs of rotation. It is classified as type V muscle. This muscle can be elevated on the thoracodorsal artery to cover large defects in the anterior chest and also, the muscle can be elevated on the segmental vessels to cover midline defects posteriorly. The aim of this study was to create a new arc of rotation on a vertical axis for the muscle and investigate effectiveness of vascular and chemical delays on the latissimus dorsi muscle flap with an inferior pedicle in an experimental rat model. We hypothesized that the latissimus dorsi muscle would be based on inferior pedicle by delay procedures. METHODS: We tested two different types of delay: vascular and combination of vascular and chemical. We also tried to determine how many days of "delay" can elicit beneficial effects of vascular and combination delays in an inferior pedicled latissimus dorsi musculocutaneous flap. To accomplish this, 48 male Sprague-Dawley rats were randomly subjected to vascular or combination delay (vascular and chemical). In addition, one ear of each rat was assigned into a delay procedure and the other ear was used as a control. Results were evaluated macroscopically, and micro-angiography and histological examinations were also performed. As a result, there was a significant difference in viable flap areas between vascular delay alone and control groups (p < 0.05). RESULTS: The higher rate of flap viability was obtained in seven-day vascular delay alone. However, there was no significant difference in the viability between seven-day vascular delay and five-day vascular delay (p < 0.05), so the earliest time when the flap viability could be obtained was at five days. The rate of flap viability was significantly higher in the vascular delay combined with chemical delay than the control group (p < 0.05). CONCLUSION: The combination of vascular and chemical delays increased the rate of viability. Nevertheless, there was no significant difference between vascular delay alone and combination of vascular and chemical delays. Chemical delay did not significantly decrease the delay period. Better histological and microangiographical results were achieved in delay groups compared to control groups. We concluded that the arch of the latissimus dorsi musculocutaneous flap can be changed and the flap can be used for various purposes with the delay procedures

Investigation of the genetic interaction between BDNF and DRD3 genes in suicidical behaviour in psychiatric disorders

Suicide is a serious public health concern, and it is partly genetic. The brain-derived neurotrophic factor (BDNF) gene has been a strong candidate in genetic studies of suicide (Zai et al, 2012; Dwivedi et al, 2010) and BDNF regulates the expression of the dopamine D3 receptor

Genetic Overlap Between Alzheimer’s Disease and Bipolar Disorder Implicates the MARK2 and VAC14 Genes

Background: Alzheimer's disease (AD) and bipolar disorder (BIP) are complex traits influenced by numerous common genetic variants, most of which remain to be detected. Clinical and epidemiological evidence suggest that AD and BIP are related. However, it is not established if this relation is of genetic origin. Here, we applied statistical methods based on the conditional false discovery rate (FDR) framework to detect genetic overlap between AD and BIP and utilized this overlap to increase the power to identify common genetic variants associated with either or both traits. Methods: We obtained genome wide association studies data from the International Genomics of Alzheimer's Project part 1 (17,008 AD cases and 37,154 controls) and the Psychiatric Genetic Consortium Bipolar Disorder Working Group (20,352 BIP cases and 31,358 controls). We used conditional QQ-plots to assess overlap in common genetic variants between AD and BIP. We exploited the genetic overlap to re-rank test-statistics for AD and BIP and improve detection of genetic variants using the conditional FDR framework. Results: Conditional QQ-plots demonstrated a polygenic overlap between AD and BIP. Using conditional FDR, we identified one novel genomic locus associated with AD, and nine novel loci associated with BIP. Further, we identified two novel loci jointly associated with AD and BIP implicating the MARK2 gene (lead SNP rs10792421, conjunctional FDR=0.030, same direction of effect) and the VAC14 gene (lead SNP rs11649476, conjunctional FDR=0.022, opposite direction of effect). Conclusions: We found polygenic overlap between AD and BIP and identified novel loci for each trait and two jointly associated loci. Further studies should examine if the shared loci implicating the MARK2 and VAC14 genes could explain parts of the shared and distinct features of AD and BIP

Manipulating Stress Responses during Spaceflight Training with Virtual Stressors

Virtual reality (VR) provides the ability to simulate stressors to replicated real-world situations. It allows for the creation and validation of training, therapy, and stress countermeasures in a safe and controlled setting. However, there is still much unknown about the cognitive appraisal of stressors and underlying elements. More research is needed on the creation of stressors and to verify that stress levels can be effectively manipulated by the virtual environment. The objective of this study was to investigate and validate different VR stressor levels from existing emergency spaceflight procedures. Experts in spaceflight procedures and the human stress response helped design a VR spaceflight environment and emergency fire task procedure. A within-subject experiment evaluated three stressor levels. Forty healthy participants each completed three trials (low, medium, high stressor levels) in VR to locate and extinguish a fire on the International Space Station (VR-ISS). Since stress is a complex construct, physiological data (heart rate, heart rate variability, blood pressure, electrodermal activity) and self-assessment (workload, stress, anxiety) were collected for each stressor level. The results suggest that the environmental-based stressors can induce significantly different, distinguishable levels of stress in individuals