Dynamic relaxation oscillations in a nonlinearly driven quartz crystal

We demonstrate thermo-mechanical relaxation oscillations in a strongly driven quartz crystal. Dynamic bifurcation leads to two stable oscillation states with a distinct electrical impedance. Slow Joule-heating, which shifts the susceptibility of the crystal, provides a feedback that leads to thermally-induced oscillations, in which the amplitude of the crystal is modulated by a relaxation cycle. The frequency of the relaxation cycle is roughly a million times lower than the resonance frequency of the crystal, and it can be adjusted by the detuning from the critical point for dynamic bifurcation. The experimental observations are reproduced by a simple model that takes into account the slow dynamics of the system.Comment: Main text: 8 pages, 4 figures. Supplementary information: 4 pages, 3 figure

Mammalian GGAs act together to sort mannose 6-phosphate receptors

The GGAs (Golgi-localized, γ ear–containing, ADP ribosylation factor–binding proteins) are multidomain proteins implicated in protein trafficking between the Golgi and endosomes. We examined whether the three mammalian GGAs act independently or together to mediate their functions. Using cryo-immunogold electron microscopy, the three GGAs were shown to colocalize within coated buds and vesicles at the trans-Golgi network (TGN) of HeLa cells. In vitro binding experiments revealed multidomain interactions between the GGAs, and chemical cross-linking experiments demonstrated that GGAs 1 and 2 form a complex on Golgi membranes. RNA interference of each GGA resulted in decreased levels of the other GGAs and their redistribution from the TGN to cytosol. This was associated with impaired incorporation of the cation-independent mannose 6-phosphate receptor into clathrin-coated vesicles at the TGN, partial redistribution of the receptor to endosomes, and missorting of cathepsin D. The morphology of the TGN was also altered. These findings indicate that the three mammalian GGAs cooperate to sort cargo and are required for maintenance of TGN structure

Vesicular Tubular Clusters between the ER and Golgi Mediate Concentration of Soluble Secretory Proteins by Exclusion from COPI-Coated Vesicles

AbstractWe have determined the concentrations of the secretory proteins amylase and chymotrypsinogen and the membrane proteins KDELr and rBet1 in COPII- and COPI-coated pre-Golgi compartments of pancreatic cells by quantitative immunoelectron microscopy. COPII was confined to ER membrane buds and adjacent vesicles. COPI occurred on vesicular tubular clusters (VTCs), Golgi cisternae, the trans-Golgi network, and immature secretory granules. Both secretory proteins exhibited a first, significant concentration step in noncoated segments of VTC tubules and were excluded from COPI-coated tips. By contrast, KDELr and rBet1 showed a first, significant concentration in COPII-coated ER buds and vesicles and were prominently present in COPI-coated tips of VTC tubules. These data suggest an important role of VTCs in soluble cargo concentration by exclusion from COPI-coated domains

Workplace mental health disclosure, sustainable employability and well-being at work:A cross-sectional study among military personnel with mental illness

Purpose Disclosure of mental illness to a supervisor can have positive (e.g. supervisor support) and negative consequences (e.g. stigma). However, research on the association between disclosure and sustainable employability and well-being at work is scarce. The aim of this study was to investigate the association between the disclosure decision (yes/no), experiences with the decision (positive/negative) and sustainable employment and well-being at work among military personnel with mental illness (N = 323). Methods A cross-sectional questionnaire study was conducted. Descriptive and regression (linear and ordinal) analyses were performed. Comparisons were made between those with positive and negative disclosure experiences. Results Disclosure decision (yes/no) was not significantly associated with any of the measures of sustainable employability and well-being at work. However, positive disclosure experiences were significantly associated with higher scores on almost all measures of sustainable employability and well-being at work. Those with negative disclosure experiences reported significantly more shame (M(pos) = 2.42, M(neg) = 2.78, p < .05) and discrimination (M(pos) = 1.70, M(neg) = 2.84, p < .001). Those with a positive disclosure experience, reported significantly more supervisor support (M(pos) = 3.20, M(neg) = 1.94, p < .001). Conclusion We did not find evidence that the disclosure decision itself is related to measures of sustainable employment and well-being at work. In contrast, how participants had experienced their (non-)disclosure decision was significantly related to almost all measures. This emphasizes the importance of the work environments reactions to disclosure and mental illness in the workplace. Future research and interventions should focus on increasing the likelihood of positive disclosure experiences through creating a more inclusive work environment, with more supervisor support and less stigma. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10926-022-10083-2

Brain lateralization and self-reported symptoms of ADHD in a population sample of adults:A dimensional approach

Many clinical studies reported a compromised brain lateralization in patients with Attention-Deficit/Hyperactivity Disorder (ADHD) without being conclusive about whether the deficit existed in the left or right hemisphere. It is well-recognized that studying ADHD dimensionally is more controlled for comorbid problems and medication effects, and provides more accurate assessment of the symptoms. Therefore, the present study applied the dimensional approach to test the relationship between brain lateralization and self-reported ADHD symptoms in a population sample. Eighty-five right-handed university students filled in the Conners’ Adult ADHD Rating Scales and performed a lateralization reaction time task. The task consists of two matching conditions: one condition requires nominal identification for letters tapping left hemisphere specialization (Letter Name-Identity condition) and the other one requires physical and visuospatial identification for shapes tapping right hemisphere specialization (Shape Physical-Identity condition). The letters or shapes to be matched are presented in left or right visual field of a fixation cross. For both task conditions, brain lateralization was indexed as the difference in mean reaction time between left and right visual field. Linear regression analyses, controlled for mood symptoms reported by a depression, anxiety and stress scale, showed no relationship between the variables. These findings from a population sample of adults do not support the dimensionality of lateralized information processing deficit in ADHD symptomatology. However, group comparison analyses showed that subjects with high level of inattention symptoms close to or above the clinical cut-off had a reduced right hemisphere processing in the Shape Physical-Identity condition