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Good social connections are proposed to positively influence the course of cognitive decline by stimulating cognitive reserve and buffering harmful stress-related health effects. Prior meta-analytic research has uncovered links between social connections and the risk of poor health outcomes such as mild cognitive impairment, dementia, and mortality. These studies have primarily used aggregate data from North America and Europe with limited markers of social connections. Further research is required to explore these associations longitudinally across a wider range of social connection markers in a global setting.
Research Objective:
We examined the associations between social connection structure, function, and quality and the risk of our primary outcomes (mild cognitive impairment, dementia, and mortality).
Method:
Individual participant-level data were obtained from 13 longitudinal studies of ageing from across the globe. We conducted survival analysis using Cox regression models and combined estimates from each study using two-stage meta-analysis. We examined three social constructs: connection structure (living situation, relationship status, interactions with friends/family, community group engagement), function (social support, having a confidante) and quality (relationship satisfaction, loneliness) in relation to the risks of three primary outcomes (mild cognitive impairment, dementia, and mortality). In our partially adjusted models, we included age, sex, and education and in fully adjusted models used these variables as well as diabetes, hypertension, smoking, cardiovascular risk, and depression.
Preliminary results of the ongoing study:
In our fully adjusted models we observed: a lower risk of mild cognitive impairment was associated with being married/in a relationship (vs. being single), weekly community group engagement (vs. no engagement), weekly family/friend interactions (vs. not interacting), and never feeling lonely (vs. often feeling lonely); a lower risk of dementia was associated with monthly/weekly family/friend interactions and having a confidante (vs. no confidante); a lower risk of mortality was associated with living with others (vs. living alone), yearly/monthly/weekly community group engagement, and having a confidante.
Conclusion:
Good social connection structure, function, and quality are associated with reduced risk of incident MCI, dementia, and mortality. Our results provide actionable evidence that social connections are required for healthy ageing.
The prevalence of anxiety and depression continues to increase, becoming the most common mental health symptoms, with a higher proportion of these two mental illnesses among college students.
Subjects and Methods
The survey randomly selects 50 college students who suffer from both anxiety and depression at a certain university and divides them into two groups. One group consists of 25 people, and each group is treated with psychotherapy combined with tourism stimulus and psychotherapy. The treatment course lasts for one year, and a follow-up visit will be conducted one year later to score anxiety and depression.
Results
The scoring results showed that among college students receiving combination therapy, the highest anxiety score was 8.6, which decreased to 3.7 after treatment. The highest depression score was 9.2, which decreased to 4.4 after combination therapy. Analysis of 25 people who received combined treatment found that the average score for depression and anxiety decreased to 4.1, and 5 of them were cured. Among college students who only received psychological treatment, the highest anxiety score was 9.1, which decreased to 5.3 after treatment. The highest depression score was 8.7, which decreased to 4.9 after psychological treatment. The average score for depression and anxiety reduction was 2.9.
Conclusions
The experimental results indicate that tourism stimulus combined with psychotherapy has a better therapeutic effect on college students with anxiety and depression than using psychotherapy alone.
Acknowledgement
The Education Department of Hainan Province, No. Hnjg2021-116; 2022 Hainan Vocational University of Science and Technology Hainan Free Trade Port Business and Tourism Research Base Project, No. HKKY2022JD-06.
An 8-week experiment was performed to investigate the influence on growth performance, plasma biochemistry, glucose metabolism and the insulin pathway of supplementation of dietary taurine to a high-carbohydrate diet for grass carp. In this study, fish were fed diets at one of two carbohydrate levels, 31·49 % (positive control) or 38·61 % (T00). The high-carbohydrate basal diet (T00), without taurine, was supplemented with 0·05 % (T05), 0·10 % (T10), 0·15 % (T15) or 0·20 % (T20) taurine, resulting in six isonitrogenous (30·37 %) and isolipidic (2·37 %) experimental diets. The experimental results showed that optimal taurine level improved significantly weight gain, specific growth rate (SGR), feed utilisation, reduced plasma total cholesterol levels, TAG and promoted insulin-like growth factor level. Glucokinase, pyruvate kinase and phosphoenolpyruvate carboxykinase activities showed a quadratic function model with increasing dietary taurine level, while hexokinase, fatty acid synthetase activities exhibited a positive linear trend. Optimal taurine supplementation in high-carbohydrate diet upregulated insulin receptor (Ir), insulin receptor substrate (Irs1), phosphatidylinositol 3-kinase (pi3k), protein kinase B (akt1), glycogen synthase kinase 3 β (gs3kβ) mRNA level and downregulated insulin-like growth factor (igf-1), insulin-like growth factor 1 receptor (igf-1R) and Fork head transcription factor 1 (foxo1) mRNA level. The above results suggested that optimal taurine level could improve growth performance, hepatic capacity for glycolipid metabolism and insulin sensitivity, thus enhancing the utilisation of carbohydrates in grass carp. Based on SGR, dietary optimal tributyrin taurine supplementation in grass carp was estimated to be 0·08 %.
Coronavirus disease 2019 (COVID-19) asymptomatic cases are hard to identify, impeding transmissibility estimation. The value of COVID-19 transmissibility is worth further elucidation for key assumptions in further modelling studies. Through a population-based surveillance network, we collected data on 1342 confirmed cases with a 90-days follow-up for all asymptomatic cases. An age-stratified compartmental model containing contact information was built to estimate the transmissibility of symptomatic and asymptomatic COVID-19 cases. The difference in transmissibility of a symptomatic and asymptomatic case depended on age and was most distinct for the middle-age groups. The asymptomatic cases had a 66.7% lower transmissibility rate than symptomatic cases, and 74.1% (95% CI 65.9–80.7) of all asymptomatic cases were missed in detection. The average proportion of asymptomatic cases was 28.2% (95% CI 23.0–34.6). Simulation demonstrated that the burden of asymptomatic transmission increased as the epidemic continued and could potentially dominate total transmission. The transmissibility of asymptomatic COVID-19 cases is high and asymptomatic COVID-19 cases play a significant role in outbreaks.
Relatively few studies have explored the differential contributions of the accumulative dosage of psychotropic medications on mortality in patients with schizophrenia.
Methods
We aimed to explore the effects of the exposure dosage of psychotropic medications on mortality during a follow-up period of 5 years with a national cohort of individuals with schizophrenia in 2010. Causes of death were linked through Taiwan's National Mortality Registry. The mean defined daily dose of antipsychotics, antidepressants, mood stabilizers, and sedative-hypnotics, were calculated and survival analyses were conducted.
Results
A total of 102 964 individuals (54 151 men, 52.59%) with schizophrenia were included. Compared to patients with no exposure to antipsychotics, those with antipsychotic exposure had better survival outcomes, regardless of antipsychotic dosage. Antidepressant exposure, in low and moderate dosage, was associated with decreased all-cause mortality; exposure to mood stabilizers appeared to be associated with an increase in all-cause mortality. Although 89.7% of the patients had been prescribed sedative-hypnotics, exposure to sedative-hypnotics was associated with dose-related increased mortality risk [hazard ratio (HR) in low dose group: 1.16, 95% confidence interval (CI) 1.07–1.27; HR in moderate dose: 1.32, 95% CI 1.21–1.44; HR in high dose: 1.83, 95% CI 1.67–2.01)].
Conclusions
The results indicate that in the treatment of schizophrenia, antipsychotics and antidepressants are associated with lower mortality when using adequate dosages and mood stabilizers and sedative-hypnotics with higher mortality compared with no use. Furthermore, exposure to sedative-hypnotics is associated with a dose-related increased mortality risk which warrants clinical attention and further study.
In droplet impacts, transitions between coalescence and bouncing are determined by complex interplays of multiple mechanisms dominating at various length scales. Here we investigate the mechanisms and governing parameters comprehensively by experiments and scaling analyses, providing a unified framework for understanding and predicting the outcomes when using different fluids. Specifically, while bouncing had not been observed in head-on collisions of water drops under atmospheric conditions, it was found in our experiments to appear on increasing the droplet diameter sufficiently. Contrarily, while bouncing was always observed in head-on impacts of alkane drops, we found it to disappear on decreasing the diameter sufficiently. The variations are related to gas draining dynamics in the inter-droplet film and suggest an easier means for controlling bouncing as compared to alternating the ambient pressure usually sought. The scaling analysis further shows that for a given Weber number, enlarging droplet diameter or fluid viscosities, or lowering surface tension contributes to a larger characteristic minimum thickness of the gas film, thus enhancing bouncing. The key dimensionless group $(O{h_{g,l}},\;O{h_l},\;{A^\ast })$ is identified, referred to as the two-phase Ohnesorge number, the Ohnesorge number of liquid and the Hamaker constant, respectively. Our thickness-based model indicates that as ${h^{\prime}_{m,c}} > 21.1{h_{cr}}$, where ${h^{\prime}_{m,c}}$ is the maximum value of the characteristic minimum film thickness $({h_{m,c}})$ and ${h_{cr}}$ is the critical thickness, bouncing occurs in both head-on and off-centre collisions. That is, when $1.2O{h_{g,l}}/(1 - 2O{h_l}) > \sqrt[3]{{{A^\ast }}}$, a fully developed bouncing regime occurs, thereby yielding a lower coalescence efficiency. The transitional Weber number is found universally to be 4.
It has long been hypothesized that personality plays a causative role in incidence and outcome of breast cancer (BC), but epidemiological evidence of association between personality and BC is inconsistent.
Method
We used two-sample Mendelian randomization analysis to estimate the impact of personality on the risk and survival of BC. In total, 109 single nucleotide polymorphisms (SNPs) were utilized as instruments of neuroticism from a large-scale Genome-Wide Association Studies (GWAS), and five SNPs were utilized as instruments of extraversion from Genetic of Personality Consortium and 23andMe. Genetic association with the risk and survival of overall and individual subtype BC were obtained from the Breast Cancer Association Consortium.
Result
Neuroticism is significantly associated with the risk of overall BC [odds ratio (OR) 1.06; 95% confidence interval (CI) 1.01–1.11; p = 0.015] and the risk of luminal A BC (OR 1.09; 95% CI 1.03–1.16; p = 0.004). Extraversion is not associated with the risk of BC. None of neuroticism or extraversion is associated with the survival of BC.
Conclusion
Neuroticism was associated with a modest increased risk of BC and particularly luminal A BC.
ABSTRACT IMPACT: This poster will demonstrate how a community issue from a CTSI Community Advisory Board member organization initiated a collaborative, community-engaged project to identify priority areas of concern and culturally appropriate mitigation strategies. OBJECTIVES/GOALS: Little is known about the health and psychosocial impact of construction on older adults living near construction sites. We applied a mixed methods approach to identify evidence-based strategies to mitigate community prioritized health and psychosocial concerns related to long-term construction on older adults in NYC’s Manhattan Chinatown. METHODS/STUDY POPULATION: In Chinatown, where approximately 20% of its residents are seniors, many are poor, have a disability, and experience ambulatory difficulties. We used a mixed methods approach including: 1) a high level scoping review of the published literature on the health impact of long-term construction for older adults; 2) key informant interviews with stakeholders; and 3) a two-part community-engaged modified Delphi process to identify priority topic areas related to construction and older adults and evidence-informed, culturally-relevant mitigation strategies. Using priority areas identified through the modified Delphi process, we conducted a literature review on the health and psychosocial impact of construction on older adults. RESULTS/ANTICIPATED RESULTS: We identified five priority topics: construction site emissions; noise; outdoor nocturnal lighting; neighborhood changes; and relocation. Long-term construction is associated with environmental and psychosocial consequences with greater negative impacts on vulnerable populations. Current NYC mitigation policies are based on general population and need revisions to consider impacts for the most vulnerable, e.g. older adults and children, to mitigate adverse health outcomes. Findings were shared with City Council members and resulted in enacting specific recommended mitigation strategies, e.g. double paned windows, etc. Seniors are highly susceptible to the effects of air pollution, noise, and environmental changes, with exposure associated with higher morbidity, mortality, and social isolation. DISCUSSION/SIGNIFICANCE OF FINDINGS: Long-term construction may pose serious health implications for seniors residing near construction sites. Standards and guidelines for the general population may not protect them. Community-driven coalitions, like community-academic partnerships, can successfully advance community priorities and inform strategies to protect the elderly.
Generating designs via machine learning has been an on-going challenge in computer-aided design. Recently, deep learning methods have been applied to randomly generate images in fashion, furniture and product design. However, such deep generative methods usually require a large number of training images and human aspects are not taken into account in the design process. In this work, we seek a way to involve human cognitive factors through brain activity indicated by electroencephalographic measurements (EEG) in the generative process. We propose a neuroscience-inspired design with a machine learning method where EEG is used to capture preferred design features. Such signals are used as a condition in generative adversarial networks (GAN). First, we employ a recurrent neural network Long Short-Term Memory as an encoder to extract EEG features from raw EEG signals; this data are recorded from subjects viewing several categories of images from ImageNet. Second, we train a GAN model conditioned on the encoded EEG features to generate design images. Third, we use the model to generate design images from a subject’s EEG measured brain activity. To verify our proposed generative design method, we present a case study, in which the subjects imagine the products they prefer, and the corresponding EEG signals are recorded and reconstructed by our model for evaluation. The results indicate that a generated product image with preference EEG signals gains more preference than those generated without EEG signals. Overall, we propose a neuroscience-inspired artificial intelligence design method for generating a design taking into account human preference. The method could help improve communication between designers and clients where clients might not be able to express design requests clearly.
Given the concerns of health inequality associated with mental illnesses, we aimed to reveal the extent of which general mortality and life expectancy at birth in people with schizophrenia, bipolar disorder and depressive disorder varied in the 2005 and 2010 nationally representative cohorts in Taiwan.
Methods
Two nationally representative samples of individuals with schizophrenia, bipolar disorder and depressive disorder were identified from Taiwan's national health insurance database in 2005 and 2010, respectively, and followed-up for consecutive 3 years. The database was linked to nationwide mortality registry to identify causes and date of death. Age-, gender- and cause-specific mortality rates were generated, with the average follow-up period of each age- and gender-band applied as ‘weighting’ for the calculation of expected number of deaths. Age- and gender-standardised mortality ratios (SMRs) were calculated for these 3-year observation periods with Taiwanese general population in 2011/2012 as the standard population. The SMR calculations were then stratified by natural/unnatural causes and major groups of death. Corresponding life expectancies at birth were also calculated by gender, diagnosis of mental disorders and year of cohorts for further elucidation.
Results
The general differential in mortality rates for people with schizophrenia and bipolar disorder remained wide, revealing an SMR of 3.65 (95% confidence interval (CI): 3.55–3.76) for cohort 2005 and 3.27 (3.18-3.36) for cohort 2010 in schizophrenia, and 2.65 (95% CI: 2.55–2.76) for cohort 2005 and 2.39 (2.31-2.48) for cohort 2010 in bipolar disorder, respectively. The SMRs in people with depression were 1.83 (95% CI: 1.81–1.86) for cohort 2005 and 1.59 (1.57-1.61) for cohort 2010. SMRs due to unnatural causes tended to decrease in people with major mental illnesses over the years, but those due to natural causes remained relatively stable. The life expectancies at birth for schizophrenia, bipolar disorder and depression were all significantly lower than the national norms, specifically showing 14.97–15.50 years of life lost for men and 15.15–15.48 years for women in people with schizophrenia.
Conclusions
Compared to general population, the differential in mortality rates for people with major mental illnesses persisted substantial. The differential in mortality for unnatural causes of death seemed decreasing over the years, but that due to natural causes remained relatively steady. Regardless of gender, people with schizophrenia, bipolar disorder and depression were shown to have shortened life expectancies compared to general population.
To investigate homocysteine (Hcy) and folate levels, prevalence of hyperhomocysteinaemia (HHcy) and folate deficiency, which are affected by lifestyles in urban, agricultural and stock-raising populations.
Design:
This is a cross-sectional study.
Setting:
Urban, agricultural and stock-raising regions in Emin, China.
Participants:
Totally 1926 subjects – 885 (45·9 %) from urban, 861 (44·7 %) from agricultural and 180 (9·4 %) from stock-raising regions – were obtained using multistage stratified random sampling. Inclusion criteria encompassed inhabitants aged ≥15 years who resided at the current address for ≥6 months and agreed to participate in the study. Surveys on health behaviour questionnaires and physical examinations were conducted and blood samples collected.
Results:
The folate level of subjects from the stock-raising region was the lowest, followed by those from the agricultural region, and the highest in those from the urban region (3·48 v. 6·50 v. 7·12 ng/ml, P < 0·001), whereas mean Hcy showed no significant difference across regions. The OR for HHcy in stock-raising regions was 1·90 (95 % CI 1·11, 3·27) compared with the urban region after adjusting for all possible covariates. The OR for folate deficiency in stock-raising and agriculture regions was 11·51 (95 % CI 7·09, 18·67) and 1·91 (95 % CI 1·30, 2·82), respectively, compared with the urban region after adjusting for all possible covariates.
Conclusions:
HHcy and folate deficiency are highly prevalent in stock-raisers, which is of important reference for HHcy control in Xinjiang, with a possibility of extension to others with approximate lifestyles.
Deep learning methods have been applied to randomly generate images, such as in fashion, furniture design. To date, consideration of human aspects which play a vital role in a design process has not been given significant attention in deep learning approaches. In this paper, results are reported from a human- in-the-loop design method where brain EEG signals are used to capture preferable design features. In the framework developed, an encoder extracting EEG features from raw signals recorded from subjects when viewing images from ImageNet are learned. Secondly, a GAN model is trained conditioned on the encoded EEG features to generate design images. Thirdly, the trained model is used to generate design images from a person's EEG measured brain activity in the cognitive process of thinking about a design. To verify the proposed method, a case study is presented following the proposed approach. The results indicate that the method can generate preferred designs styles guided by the preference related brain signals. In addition, this method could also help improve communication between designers and clients where clients might not be able to express design requests clearly.
Introduction: To investigate the effects of paroxetine (PAR) on motor and cognitive function recovery in patients with non-depressed ischemic stroke (nD-AIS).
Methods: One hundred sixty-seven patients hospitalized for non-depressed acute ischemic stroke were selected and divided into treatment (T) and control (C) groups using a random number table. All patients received conventional secondary ischemic stroke prevention and rehabilitation training; patients in Group T additionally received treatment with PAR (10 mg/day during week 1 and 20 mg/day thereafter) for 3 months. The follow-up observation lasted 6 months. The Fugl–Meyer motor scale (FMMS), Montreal cognitive assessment (MoCA), and Hamilton depression scale (HAMD) were used on D0, D15, D90, and D180 (T0, 1, 2, and 3, respectively; D180 = 90 days after treatment cessation) after study initiation, and scores were compared between the groups.
Results: The FMMS and MoCA scores differed significantly between Groups T and C at T2 and T3 (p < .05); by contrast, these scores did not differ significantly between the groups at T1 (p > .05). Furthermore, the HAMD scores differed significantly between the two groups at T3 (p < .05), but not at T1 and T2 (p > .05).
Conclusions: PAR treatment may improve motor and cognitive function recovery in patients with nD-AIS. Moreover, PAR may reduce the occurrence of depression after stroke.
Evidence regarding the relationships between the socioeconomic status and
long-term outcomes of individuals with bipolar affective disorder (BPD)
is lacking.
Aims
We aimed to estimate the effects of baseline socioeconomic status on
longitudinal outcomes.
Method
A national cohort of adult participants with newly diagnosed BPD was
identified in 2008. The effects of personal and household socioeconomic
status were explored on outcomes of hospital treatment, mortality and
healthcare costs, over a 3-year follow-up period (2008–2011).
Results
A total of 7987 participants were recruited. The relative risks of
hospital treatment and mortality were found elevated for the ones from
low-income households who also had higher healthcare costs. Low premium
levels did not correlate with future healthcare costs.
Conclusions
Socioeconomic deprivation is associated with poorer outcome and higher
healthcare costs in BPD patients. Special care should be given to those
with lower socioeconomic status to improve outcomes with potential
benefits of cost savings in the following years.
To assess the association between maternal caffeine intake and risk of pregnancy loss using a systematic review and meta-analysis.
Design
Categorical and dose–response meta-analysis of prospective studies.
Setting
Relevant articles were identified by searching MEDLINE and SCOPUS databases through 30 January 2015. Two authors independently extracted information from eligible studies. Random-effects models were used to derive the summary relative risks (RR) and corresponding 95 % CI for specific categories of caffeine consumption and for a continuous association using generalized least-squares trend estimation.
Subjects
A total of 130 456 participants and 3429 cases in fourteen included studies.
Results
Compared with the reference category with no or very low caffeine intake, the RR (95 % CI) of pregnancy loss was 1·02 (0·85, 1·24; I2=28·3 %) for low intake (50–149 mg/d), 1·16 (0·94, 1·41; I2=49·6 %) for moderate intake (150–349 mg/d), 1·40 (1·16, 1·68; I2=18·6 %) for high intake (350–699 mg/d) and 1·72 (1·40, 2·13; I2=0·0 %) for very high intake (≥700 mg/d). In the dose–response analysis, each 100 mg/d increment in maternal caffeine intake (~1 cup of coffee) was associated with 7 % (95 % CI 3 %, 12 %) higher risk of pregnancy loss. Our results may have been affected by publication bias, but the association remained significant for the subset of larger studies. Furthermore, adjustment for smoking and pregnancy symptoms may have been incomplete, potentially resulting in residual confounding.
Conclusions
Albeit inconclusive, higher maternal caffeine intake was associated with a higher risk of pregnancy loss and adherence to guidelines to avoid high caffeine intake during pregnancy appears prudent.
Early life environments interact with genotype to determine stable phenotypic outcomes. Here we examined the influence of a variant in the brain-derived neurotropic factor (BDNF) gene (Val66Met), which underlies synaptic plasticity throughout the central nervous system, on the degree to which antenatal maternal anxiety associated with neonatal DNA methylation. We also examined the association between neonatal DNA methylation and brain substructure volume, as a function of BDNF genotype. Infant, but not maternal, BDNF genotype dramatically influences the association of antenatal anxiety on the epigenome at birth as well as that between the epigenome and neonatal brain structure. There was a greater impact of antenatal maternal anxiety on the DNA methylation of infants with the methionine (Met)/Met compared to both Met/valine (Val) and Val/Val genotypes. There were significantly more cytosine–phosphate–guanine sites where methylation levels covaried with right amygdala volume among Met/Met compared with both Met/Val and Val/Val carriers. In contrast, more cytosine–phosphate–guanine sites covaried with left hippocampus volume in Val/Val infants compared with infants of the Met/Val or Met/Met genotype. Thus, antenatal Maternal Anxiety × BDNF Val66Met Polymorphism interactions at the level of the epigenome are reflected differently in the structure of the amygdala and the hippocampus. These findings suggest that BDNF genotype regulates the sensitivity of the methylome to early environment and that differential susceptibility to specific environmental conditions may be both tissue and function specific.
Au nanoparticles (Au NPs) have attracted much interest owing to their unique optical properties. In this paper, a facile process has been successfully developed to synthesize the SiO2/Au hybrid microspheres with a diameter of 200 nm via the galvanic replacement of SiO2/Ag hybrid microspheres and chlorauric acid (HAuCl4) solution. The as-prepared products were investigated by x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM, JEOL-6700F), and transmission electron microscopy (TEM, JEOL 3010), respectively. As expected, the as-prepared SiO2/Au hybrid microspheres show strong chemical stability and superior catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The SiO2/Au hybrid microspheres would be found widely used in wastewater treatment, catalytic reaction, bacteriostatic and bactericidal applications.
Using the discrete ordinate method, we solve the equations of phonon radiative transfer for thin films analytically, and deduce closed-form expressions for three thermophysical properties including the phonon intensity, heat flux density and effective phonon thermal conductivity. These analytical expressions provide a fast and convenient way to analyze heat conduction behavior in thin films, and thus allowing us to comprehend how the film thickness and bulk phonon mean free path affects the thermophysical properties. Also we extend these expressions from thin films to one period of superlattices, and demonstrate that adjusting the thickness ratio of two layers can control its effective phonon thermal conductivity.
Predator–prey interactions play major and direct roles in the structuring of zooplankton communities. Asplanchna usually predates ciliates, rotifers, cladocerans and sometimes even copepods, its predation may drive not only the ecological, but also the evolutionary dynamics of prey populations. In the present study, the life-table demography and the population growth of Asplanchna brightwelli were investigated at four temperatures (16, 20, 24 and 28°C) using Brachionus angularis as prey at four densities (10, 20, 30 and 40 ind.mL−1). The results showed that temperature affected significantly all the life-table demographic parameters (age-specific survivorship and fecundity, average lifespan, life expectancy at hatching, generation time, net reproductive rate and intrinsic rate of population increase) and the population growth rate obtained from the population growth studies, prey density affected the generation time, the net reproductive rate, the intrinsic rate of population increase and the population growth rate, and the interaction between temperature and prey density affected the generation time and the population growth rate. Both the average lifespan and the life expectancy at hatching were the longest at 16°C, the generation times were longer at lower temperatures (16 and 20°C) and higher prey densities (30 and 40 ind.mL−1), the net reproductive rates were higher at lower temperatures (16 and 20°C) and 20–40 ind.mL−1 of B. angularis, and the population growth rates were higher at 20°C under 20–40 ind.mL−1 of B. angularis.
Phosphodiesterase 2 (PDE2) is an enzyme responsible for hydrolysis of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) to restrict intracellular signalling of these second messenger molecules. This study investigated how PDE2 inhibitor Bay 60-7550 affects the dysregulated glucocorticoid signalling in neuronal cells and regulates depressive behaviours after chronic stress in mice. We found that exposure of hippocampal neurons to corticosterone resulted in time- and concentration-dependent increases in PDE2 expression. These intriguing findings were confirmed in the hippocampal cell line HT-22. After corticosterone exposure for 24 h, HT-22 cells showed a concentration-dependent increase in mRNA levels for PDE2 subtypes, PDE2A1 and 2A3, as well as for the total PDE2A protein expression. Bay 60-7550 was found to reverse the cell lesion induced by corticosterone (50 μm). This neuroprotective effect was blocked by pretreatment with protein kinase G inhibitor KT5823, but not protein kinase A inhibitor H89, suggesting the involvement of cGMP-dependent signalling. Although Bay 60-7550 treatment for 24 h did not change the levels of phosphorylated mitogen-activated protein kinases ERK1/2 (pERK) and phosphorylated cAMP response element-binding protein (pCREB), it down-regulated pERK at 2 h and up-regulated a CREB co-activator, CREB-binding protein, at 24 h. Both of these effects were blocked by KT 5823. Furthermore, Bay 60-7550 reversed corticosterone-induced down-regulation of brain-derived neurotrophic factor protein levels 24 h after corticosterone exposure. In behavioural testing, Bay 60-7550 produced antidepressant-like effects and reduced corticosterone levels in stressed mice, further supporting the involvement of a PDE2-dependent pathway in mediating Bay 60-7550's effect during stress hormone insults.