Social Media Use as a Predictor of Positive and Negative Affect: An Ecological Momentary Assessment Study of Adolescents with and without Clinical Depression.

Social media use is common in adolescents, with implications for psychosocial development and the emergence of depression. Yet, little is known about the time-linked connections between social media use and adolescents' affective experiences and how they may differ between depressed and non-depressed youth. We leveraged ecological momentary assessment in adolescents oversampled for current depression to examine (1) associations between social media use and concurrent and later positive and negative affect and (2) sex and presence of a depressive disorder as moderators of these associations. Adolescents aged 14-17 with (n = 48) and without (n = 97) clinical depression, as indicated via clinical interview, reported momentary social media use and positive and negative affect seven times per day for one week. Multilevel modeling indicated that social media use was associated with reduced positive affect both concurrently and at the next assessment. Further, among clinically depressed youth only, social media use was associated with reduced negative affect at the next assessment. Results suggest that social media use may reduce both positive and negative affect, highlighting the nuanced relation between adolescent social media use and emotional health and laying the groundwork for future research to address several open questions.

Ursids evolved dietary diversity without major alterations in metabolic rates.

The diets of the eight species of ursids range from carnivory (e.g., polar bears, Ursus maritimus) to insectivory (e.g., sloth bears, Melursus ursinus), omnivory (e.g., brown bears, U. arctos), and herbivory (e.g., giant pandas, Ailuropoda melanoleuca). Dietary energy availability ranges from the high-fat, highly digestible, calorically dense diet of polar bears (~ 6.4 kcal digestible energy/g fresh weight) to the high-fiber, poorly digestible, calorically restricted diet (~ 0.7) of giant pandas. Thus, ursids provide the opportunity to examine the extent to which dietary energy drives evolution of energy metabolism in a closely related group of animals. We measured the daily energy expenditure (DEE) of captive brown bears in a relatively large, zoo-type enclosure and compared those values to previously published results on captive brown bears, captive and free-ranging polar bears, and captive and free-ranging giant pandas. We found that all three species have similar mass-specific DEE when travel distances and energy intake are normalized even though their diets differ dramatically and phylogenetic lineages are separated by millions of years. For giant pandas, the ability to engage in low-cost stationary foraging relative to more wide-ranging bears likely provided the necessary energy savings to become bamboo specialists without greatly altering their metabolic rate.

Psychometric Properties and Factor Structure of the Multidimensional Behavioral Health Screen (MBHS) With a University Sample.

The Multidimensional Behavioral Health Screen (MBHS) is a brief screening measure of behavioral health symptoms. Although the measure was first developed for primary care, it is likely to have clinical utility in other settings. This study examined the MBHS's factor structure and psychometric properties with a university undergraduate and graduate student sample (n = 602, 58.6% female, 75.9% White, primarily aged 20-24) during the COVID-19 pandemic. MBHS subscale scores demonstrated internal consistency reliability and both convergent and discriminant relations with external, criterion variables. Confirmatory factor analyses supported a 7-subscale factor structure of the MBHS and did not find evidence of higher order factors. Clinical and theoretical implications, as well as future research directions, are discussed.

Delta-8- and Delta-9-THC Use Frequency, Use Motives, and Mental Health Outcomes.

Use of delta-8-THC ("delta-8") has proliferated after the passage of the 2018 Farm Bill. Yet, research on the mental health effects of this increasingly popular cannabinoid is scant. The current study sought to examine mental health correlates of delta-8 use frequency and motives, investigate whether delta-8 use motives predict use frequency, and compare use motives and problems between delta-8 and traditional cannabis. Participants consisted of 363 self-reported delta-8 users who completed measures of delta-8 use frequency, motives, and problems that were adapted from comparable measures for cannabis, as well as measures of mental health outcomes. Delta-8 use frequency was unrelated to use problems and other mental health outcomes. Delta-8 use frequency was positively associated with social and coping motives, but negatively associated with enhancement and conformity motives. Coping and conformity motives were associated with greater depression, anxiety, insomnia, and delta-8 use problems. Participants were more likely to report coping and enhancement motives for delta-8 use compared to cannabis use, but less likely to report conformity motives. Further longitudinal research is needed to assess causality for associations between delta-8 use frequency, use motives, and mental health outcomes.

Positive Interpretation Bias Predicts Longitudinal Decreases in Social Anxiety.

Theoretical models of social anxiety suggest that distorted interpretation processes contribute to its development and maintenance, although the pathways through which this occurs are not well understood. Therefore, the present longitudinal study sought to determine whether negative interpretation bias, positive interpretation bias, and interpretation inflexibility (the degree to which participants correctly revise initial interpretations) predict changes in social anxiety over time. In an important advance over prior studies, individual differences in working memory capacity (WMC) were accounted for, as WMC is thought to play a crucial role in the generation and maintenance of interpretation biases. Following a baseline assessment of social anxiety, interpretation biases, and WMC, participants completed follow-up assessments of social anxiety both 2 weeks (n = 106) and 4 weeks (n = 96) later. After controlling for baseline social anxiety and WMC, greater positive interpretation bias was found to predict lower social anxiety at both follow-ups. Neither negative interpretation bias nor interpretation inflexibility was significantly associated with follow-up social anxiety. These results provide support for greater positive interpretation bias as a facilitator of decreases in social anxiety and a potential target for clinical intervention.

Dampening of positive affect and depression: A meta-analysis of cross-sectional and longitudinal relationships.

Dampening responses to positive affect have been posited to confer vulnerability to depression, but longitudinal studies have not consistently shown dampening tendencies to predict follow-up depression. The cross-sectional, longitudinal, and cross-lagged relationships between dampening and depression were determined using meta-analytic methods. A systematic literature search of the PsycINFO and PubMed databases supplemented by Google Scholar yielded 60 samples suitable for inclusion in the cross-sectional analyses and 12 samples meeting criteria for the longitudinal analyses. In the first meta-analytic study to examine the relationship between dampening and depression, we found dampening to be associated with depression both cross-sectionally (r = .45) and prospectively (r = 0.34). Crucially, dampening at baseline remained a significant predictor of follow-up depression even after controlling for baseline levels of depression in cross-lagged analyses (ß = .09). A bidirectional effect was also found, with baseline levels of depression predicting follow-up tendencies to engage in dampening (r = 0.36). This relationship was again diminished but remained significant after controlling for initial levels of dampening (ß = .14). These results suggest that dampening responses to positive affect are a risk factor for the development of depression and highlight the importance of targeting dampening cognitions in treatment.

A comparison of telehealth versus in-person group therapy: Results from a DBT-based dual diagnosis IOP.

OBJECTIVE: The effectiveness of remotely delivered group interventions and treatments for individuals with more complex psychiatric presentations is understudied. Nevertheless, the emergence of the COVID-19 pandemic shifted such treatments from in-person to remote service delivery without the establishment of comparable effectiveness between in-person and remote delivery. The current study presents the results of a private practice's transition from in-person treatment delivery to a videoconference-delivered Dialectical Behavior Therapy (DBT)-based intensive outpatient program (IOP) for individuals with comorbid mental health and substance use disorder diagnoses in response to the pandemic. METHODS: Change in symptoms of depression, anxiety, and stress following completion of the IOP was compared between the in-person and videoconference groups. RESULTS: Large reductions in symptoms were found following completion of the IOP for both the in-person and videoconference groups. Furthermore, no significant differences in symptom reduction were found between the groups. CONCLUSION: Although large-scale replication is needed, these results suggest that IOPs and other intensive group therapies delivered via videoconference may be as effective as in-person therapies, even among individuals with more complex psychiatric presentations. Providers who have transitioned group therapies to videoconference formats or are considering creating remote groups can be more confident that they are not sacrificing treatment efficacy.

Ruminative Inertia, Emotion Regulation, and Depression: A Daily-Diary Study.

Emotional suppression and cognitive reappraisal are emotion regulation strategies that have been linked to the severity of depression. Recent research has shown that greater ruminative inertia (i.e., rumination that is more resistant to change across time) is also associated with higher levels of depressive symptoms in clinical samples. However, it is unknown how tendencies to use suppression or reappraisal might be related to the inertia of rumination from day to day. After completing a baseline assessment of depressive symptoms and trait emotional suppression and cognitive reappraisal use, undergraduates (n = 94) completed daily-diary questionnaires assessing rumination for two weeks. Both higher depressive symptoms and greater tendencies to use suppression predicted stronger ruminative inertia, while tendencies to use reappraisal were unrelated to ruminative inertia. These results suggest that maladaptive emotion regulation strategies may contribute to a pattern of rumination that is more resistant to change over time. They also provide the first evidence that ruminative inertia is positively associated with depressive symptoms in a nonclinical sample.

Naturalistic Partial Sleep Deprivation Leads to Greater Next-Day Anxiety: The Moderating Role of Baseline Anxiety and Depression.

The detrimental effects of insufficient sleep on emotional functioning have been well established. Total sleep deprivation usually leads to increased anxiety and depressive symptoms the following day. However, no study has yet examined the relationships between unmanipulated partial sleep deprivation and next-day symptoms of anxiety and depression in everyday life, which this study sought to characterize. Participants (N = 94) completed daily diary surveys twice per day for 2 weeks without instructions to alter their sleep in any way. Nights of spontaneous, naturally occurring partial sleep deprivation were followed by increased levels of self-reported symptoms of anxious arousal the next day, but were unrelated to next-day symptoms of anhedonic depression or general distress. The relationship between partial sleep deprivation and next-day anxious arousal was found to be moderated by both baseline depressive symptoms and anxiety such that individuals reporting higher levels of depression or anxiety at baseline showed relatively greater increases in symptoms of anxiety following partial sleep deprivation. These results suggest that partial sleep deprivation occurring in everyday life can lead to higher next-day levels of anxious arousal, a relationship that is particularly deleterious for individuals with higher overall levels of anxiety or depressive symptoms.

Cognitive risk, coping-oriented substance use, and increased avoidance tendencies among depressed outpatients: A prospective investigation.

OBJECTIVE: The present study was designed to assess the interplay between depressive cognition, coping-oriented substance use, and future behavioral disengagement tendencies. Cognitive risk subtypes examined include brooding rumination, attributional bias (internal/stable/global), and dysfunctional attitudes. METHOD: Individuals were recruited from outpatient treatment settings and met criteria for a unipolar depressive disorder (N = 70; 66% female; 81% White; Mage = 31; SDage = 13.2). Participants completed self-report measures of brooding rumination, attributional style, dysfunctional attitudes, coping-oriented substance use, and behavioral disengagement tendencies following a 3-week period. RESULTS: Brooding rumination, stable attributional style, and dysfunctional attitudes were positively associated with later behavioral disengagement tendencies. Coping-oriented substance use moderated associations between both internal attributional style, as well as dysfunctional attitudes onto later behavioral disengagement. CONCLUSIONS: With regard to stress-related avoidance, subsyndromal substance use may play a detrimental role among cognitively vulnerable, depressed outpatients when said drug or alcohol use serves as a means of coping.

Nutrient and mineral composition during shoot growth in seven species of Phyllostachys and Pseudosasa bamboo consumed by giant panda.

During the annual period of bamboo shoot growth in spring, free-ranging giant pandas feed almost exclusively on the shoots while ignoring the leaves and full- height culm. Little is known about the nutritional changes that occur during bamboo shoot growth, if nutritional changes differ among species, or how these changes might influence forage selection. Our objective was to examine the nutrient and mineral composition during three phases of shoot growth (<60, 90-150 and >180 cm) for seven species of bamboo (Phyllostachys (P.) aurea, P. aureosulcata, P. bissetii, P. glauca, P. nuda, P. rubromarginata, Pseudosasa japonica) fed to captive giant pandas at the Memphis Zoo. Total dietary fiber content of bamboo shoots increased (p < 0.0001) from an overall species average of 61% dry matter (DM) at < 60 cm to 75% DM at shoot heights > 180 cm, while crude protein, fat and ash exhibited significant declines (p < 0.05). Phyllostachys nuda had the overall greatest (p = 0.007) crude protein (21% DM) and fat (4% DM) content, and lowest overall total fibre (61% DM) content compared to the other species examined. In contrast, Pseudosasa japonica had the overall lowest crude protein and fat, and relatively higher fibre content (9%, 3% and 74% respectively). Concentrations of Zn and Fe were highest in shoots <60 cm (10-50 µg/g DM) and decreased (p < 0.05) during growth in all species examined. Concentrations of Ca, Cu, Mn, Na and K varied among species and were largely unaffected by growth stage. Due to their higher concentrations of nutrients and lower fibre content in comparison to culm and leaf, bamboo shoots should be a major component of captive giant panda diets when available.

Heat-treated myosin does not bind ATPase--inhibiting antibodies.

Polyclonal antibodies to native chicken pectoral fast-twitch myosin are directed to all subfragments of the molecule (S1, S2 and LMM), as seen in the ELISA and Western blotting techniques. The antibodies inhibit the Ca(2+)-activated myosin ATPase. Absorption of the antibodies with native myosin abolishes these reactions. Heat treatment of myosin for 2h at 40 degrees C will inactivate myosin ATPase and alter its antibody binding pattern: the binding of antibodies to the rod fractions is reduced, that to the globular head (S1) completely abolished. Thus, these antibodies are useful as sensitive probes for the structural integrity of the myosin head.

Embryonic chicken gizzard: smooth muscle and non-muscle myosin isoforms.

Antibodies to smooth muscle and non-muscle myosin allow the development of smooth muscle and its capillary system in the embryonic chicken gizzard to be followed by immunofluorescent techniques. Although smooth muscle development proceeds in a serosal to luminal direction, angiogenetic cell clusters develop independently at the luminal side close to the epithelial layer, and the presumptive capillaries invade the developing muscle in a luminal to serosal direction. The smooth muscle and non-muscle myosin heavy chains in this avian system cannot be separated by SDS polyacrylamide gel electrophoresis and do not show isoform specificity in immunoblotting, unlike the system found in mammals. Only two myosin heavy chains with M(r) of 200 and 196 kDa were separable and considerable immunological cross-reactivity was found between the denatured myosin isoform heavy chains.

Characterization of inositol 1,4,5-trisphosphate-sensitive (IsCaP) and -insensitive (IisCaP) nonmitochondrial Ca2+ pools in rat pancreatic acinar cells.

We have measured Ca2+ uptake and Ca2+ release in isolated permeabilized pancreatic acinar cells and in isolated membrane vesicles of endoplasmic reticulum prepared from these cells. Ca2+ uptake into cells was monitored with a Ca2+ electrode, whereas Ca2+ uptake into membrane vesicles was measured with 45Ca2+. Using inhibitors of known action, such as the H+ ATPase inhibitors NBD-Cl and NEM, the Ca2+ ATPase inhibitor vanadate as well as the second messenger inositol 1,4,5-trisphosphate (IP3) and its analog inositol 1,4,5-trisphosphorothioate (IPS3), we could functionally differentiate two nonmitochondrial Ca2+ pools. Ca2+ uptake into the IP3-sensitive Ca2+ pool (IsCaP) occurs by a MgATP-dependent Ca2+ uptake mechanism that exchanges Ca2+ for H+ ions. In the absence of ATP Ca2+ uptake can occur to some extent at the expense of an H+ gradient that is established by a vacuolar-type MgATP-dependent H+ pump present in the same organelle. The other Ca2+ pool takes up Ca2+ by a vanadate-sensitive Ca2+ ATPase and is insensitive to IP3 (IisCaP). The IsCaP is filled at "higher" Ca2+ concentrations (approximately 10(-6) mol/liter) which may occur during stimulation. The low steady-state [Ca2+] of approximately 10(-7) mol/liter is adjusted by the IisCaP. It is speculated that both Ca2+ pools can communicate with each other, the possible mechanism of which, however, is at present unknown.

Characterization of MgATP-driven H+ uptake into a microsomal vesicle fraction from rat pancreatic acinar cells.

In microsomal vesicles, as isolated from exocrine pancreas cells, MgATP-driven H+ transport was evaluated by measuring H+-dependent accumulation of acridine orange (AO). Active H+ uptake showed an absolute requirement for ATP with simple Michaelis-Menten kinetics (Km for ATP 0.43 mmol/liter) with a Hill coefficient of 0.99. H+ transport was maximal at an external pH of 6.7, generating an intravesicular pH of 4.8. MgATP-dependent H+ accumulation was abolished by protonophores, such as nigericin (10(-6) mol/liter) or CCCP (10(-5) mol/liter), and by inhibitors of nonmitochondrial H+ ATPases, such as NEM or NBD-Cl, at a concentration of 10(-5) mol/liter. Inhibitors of both mitochondrial and nonmitochondrial H+ pumps, such as DCCD (10(-5) mol/liter) or Dio 9 (0.25 mg/ml), reduced microsomal H+ transport by about 90%. Vanadate (2 x 10(-3) mol/liter), a blocker of those ATPases, which form a phosphorylated intermediate, did not inhibit H+ transport. The stilbene derivative DIDS (10(-4) mol/liter), which inhibits anion transport systems, abolished H+ transport completely. MgATP-dependent H+ transport was found to be anion dependent in the sequence Cl- greater than Br- greater than gluconate-; in the presence of SO2-4, CH3COO- or No-3, no H+ transport was observed. MgATP-dependent H+ accumulation was also cation dependent in the sequence K+ greater than Li+ greater than Na+ = choline+. As shown by dissipation experiments in the presence of different ion gradients and ionophores, both a Cl- and a K+ conductance, as well as a small H+ conductance, were found in the microsomal membranes. When membranes containing the H+ pump were further purified by Percoll gradient centrifugation (ninefold enrichment compared to homogenate), no correlation with markers for endoplasmic reticulum, mitochondria, plasma membranes, zymogen granules or Golgi membranes was found. The present data indicate that the H+ pump located in microsomes from rat exocrine pancreas is a vacuolar- or "V" -type H+ ATPase and has most similarities to that described in endoplasmic reticulum, Golgi apparatus or endosomes.

Photoaffinity labeling with GTP-gamma-azidoanilide of a cholera toxin-sensitive 40 kDa protein from pancreatic acinar cells.

In isolated pancreatic acinar plasma membranes a 40 kDa protein was labeled with the photoreactive GTP-analogue [alpha 32P] GTP-gamma-azidoanilide. Increased incorporation of the photolabel into the 40 kDa protein was obtained in the presence of increasing concentrations of cholecystokinin-octapeptide (10(-8) - 10(-5) M) but not with carbachol. Adenylyl cyclase activating hormones such as vasoactive intestinal polypeptide and secretin had no effect. Pretreatment of plasma membranes with cholera toxin reduced incorporation of GTP-gamma-azidoanilide into the 40 kDa protein by about 30%. This reduction was reversed if ADP-ribosylation by cholera toxin was performed in the presence of cholecystokinin, whereas carbachol had no effect. The data indicate that a cholera toxin-sensitive 40 kDa GTP-binding protein is involved in functionally coupling cholecystokinin- but not muscarinic acetylcholine-receptors to phospholipase C.

Coupled Na+-H+ exchange in isolated acinar cells from rat exocrine pancreas.

Isolated acinar cells from the rat exocrine pancreas were loaded with 6-carboxyfluorescein diacetate (CFDA), and the intracellular pH (pHi) was estimated from the pH-dependent fluorescence intensity of trapped 6-carboxyfluorescein liberated from CFDA by intracellular esterases. The intracellular fluorescence intensity was calibrated by equilibrating the internal and external pH with nigericin in K+ buffers. In the absence of Na+ (130 mmol/l K+) a pHi of 6.86 +/- 0.04 was found; in its presence (130 mmol/l Na+) a pHi of 7.17. Acute addition of Na+ increased intracellular pH with increasing Na+ concentrations, reaching a maximum at 150 mmol/l with an apparent Km of approximately 40 mmol/l. Of the different cations tested on pHi, such as Li+, K+, Rb+, and Cs+, only Li+ showed an effect on pHi similar to that of Na+. Amiloride dose dependently inhibited both Na+- and Li+-induced alkalinization (apparent Km approximately 10(-5) mol/l). In the presence of ouabain pHi was decreased by 0.2 pH units. Intracellular acidification induced by permeable buffers such as acetic acid-acetate or CO2-HCO3- was dissipated more rapidly in the presence of Na+ compared with K+ or with Na+ and amiloride in the medium. In Li+-preincubated cells intracellular acidification was higher in the absence of Li+ in the extracellular medium than in its presence. This Li+ gradient-induced acidification was dependent on the extracellular pH, was highest at an extracellular pH of 7.05, and decreased with increasing pH to 7.5. The results allow the conclusion that a coupled Na+-H+ exchange is present in pancreatic acinar cells and that the intracellular pH rather than the extracellular Na+ concentration regulates this transport mechanism.