[A study on longitudinal changes in white matter microstructure of parents who have lost their only child based on diffusion tensor imaging and its relationship with symptoms of posttraumatic stress disorder].

Objective: To investigate the longitudinal changes of white matter microstructural based on diffusion tensor imaging in parents who lost their only child without psychiatric disorders and its relationship with symptoms of posttraumatic stress disorder (PTSD). Methods: Parents who had who lost their only child and without psychiatric disorders in Jiangsu Province, from September 2016 to March 2017, were retrospectively collected (TENP group, 32). MRI scans were performed at baseline and at the end of 5-year follow-up, and the Clinician Administered PTSD Scales (CAPS) were used for assessing the severity of symptoms. Additionally, sex, age and education level matched healthy subjects were recruited as healthy controls (control group, 27) and underwent MRI scanning using the same protocol. The differences of fractional anisotropy (FA) values between TENP group and control group at baseline were analyzed by using Tract-based spatial statistics method, and the brain areas of lateral differences were used as the regions of interest for longitudinal follow-up analysis of TENP group. Partial correlation analysis was used to evaluate the relationship between FA values changes in longitudinal differences in brain regions and CAPS scores. Results: Compared with the control group, FA values of the right cingulate gyrus, Uncinate fasciculus, superior longitudinal fasciculus, corticospinal tract, Inferior fronto-occipital fasciculus, Inferior longitudinal fasciculus and forceps major in TENP group were decreased at baseline ((0.613±0.032) vs (0.631±0.034), (0.539±0.048) vs (0.563±0.045), (0.534±0.033) vs (0.558±0.039), (0.560±0.038) vs (0.580±0.030), (0.519±0.023) vs(0.549±0.024), (0.489±0.038) vs (0.518±0.027), (0.499±0.027) vs (0.533±0.032); all P<0.05). From baseline to follow-up, scores of trauma reexperience symptoms and avoidance/numbness symptoms were decreased ((5.2±2.8) vs (8.1±4.9), (4.0±3.2) vs (6.6±5.4); all P<0.05); FA values of the right corticospinal tract, Inferior fronto-occipital fasciculus, Inferior longitudinal fasciculus and forceps major were decreased ((0.523±0.049) vs (0.537±0.049), (0.568±0.052) vs (0.590±0.050), (0.540±0.063) vs (0.559±0.059), (0.520±0.059) vs (0.547±0.059); all P<0.05); The decrease of FA values of the right Inferior fronto-occipital fasciculus and right Inferior longitudinal fasciculus was negatively correlated with the decrease of avoidance/numbness symptoms scores (r=-0.458, -0.374, respectively, all P<0.05). Conclusions: The trauma of parents who lost their only child can result in impaired microstructural integrity of white matter. As the post-traumatic time goes by, parents who have lost their only child do not develop to PTSD and other psychiatric disorders, and the clinical symptoms are alleviated, the damage of the white matter microstructure continued to progress.

Relative importance of seed drying rate, desiccation tolerance, and cryotolerance for the conservation of Ardisia elliptica, A. brunnescens and A. virens.

BACKGROUND: The pan-tropical genus Ardisia has more than 400 species and is of high horticultural and medicinal value. Due to overexploitation it is important to conserve the germplasm of this genus. OBJECTIVE: To investigate the feasibility and methods of cryopreservation for long-term seed storage of three Ardisia species: A. elliptica Thunb., A. brunnescens Walker, and A. virens Kurz. METHODS: We tested whether rapid desiccation can increase desiccation tolerance and cryotolerance, and whether the thawing rate can affect cryopreservation success. Seeds were subjected to three desiccation treatments: 1) activated silica gel at 25 +/- 2 degree C, and 4% relative humidity (RH); 2) saturated NaCl solution in closed jars in 25 +/- 2 degree C and 75% RH; and 3) air-drying at room conditions at 27 +/- 2 degree C and RH 60% for different desiccation durations (12h, 24h, 48h, 96h, and 196h). Seeds were then assessed for desiccation tolerance and cryotolerance after rapid thawing (direct immersion in 36 degree C water bath for 2 min) or slow thawing (at 27°C for 1 h). RESULTS: For all three species, desiccation method and duration significantly affected cryotolerance (P < 0.0001). Fast desiccation did not improve germination compared to slower desiccation (P < 0.01). Whereas A. elliptica germination was unaffected by desiccation duration, drying time significantly (P < 0.0001) affected germination percentage in the other two species especially after 48h. Although slow thawing improved cryotolerance of A. brunnescens seeds (P < 0.05), there was no significant effect of thawing rate on A. elliptica. A. virens seed did not survive cryopreservation. CONCLUSIONS: Cryopreservation protocols of Ardisia species may be species-specific and should be established for each species in the genus so that cryopreservation can be used as a successful conservation strategy.

Impact of COVID-19 on the sleep-wake patterns of preschool children.

OBJECTIVE: To explore the impact of the COVID-19 pandemic on the sleep-wake patterns of preschool children. METHODS: A cohort of preschoolers established before the COVID-19 pandemic was invited to participate in this study. Data including children's demographics, their own and parental sleep-wake patterns, physical activities, and screen time were collected through an online questionnaire from August to September 2020. A comparison was made on the collected data from the same cohort of children before and during the pandemic. RESULTS: The cohort which was established before the pandemic consisted of 3720 preschoolers. For this current study, 642 (17%) participated, and 497 (13%) children who fulfilled the eligibility criteria were included in the final analysis. They showed a delay in their bedtime and wake time on both weekdays and weekends with a 15-30 min increase in nocturnal sleep duration. However, with a reduction in nap time, the average daily sleep duration was shortened by 16.3 ± 64.3 min (p < 0.001) and 27.5 ± 72.9 min (p < 0.001) during weekdays and weekends, respectively. Screen time was increased while outdoor activity duration was decreased. Parental sleep/wake times were also delayed with an increase in sleep duration. Children's sleep habits were associated with screen time and parental sleep/wake patterns. CONCLUSION: Despite school suspension during the COVID-19 pandemic, preschoolers were not sleeping longer. Screen time and parental sleep/wake patterns were the major factors driving the preschoolers' sleep habits. Health education is required to control screen time in children and to promote sleep hygiene among all family members.