Short- and long-term predictions of chaotic flows and extreme events: a physics-constrained reservoir computing approach.

We propose a physics-constrained machine learning method-based on reservoir computing-to time-accurately predict extreme events and long-term velocity statistics in a model of chaotic flow. The method leverages the strengths of two different approaches: empirical modelling based on reservoir computing, which learns the chaotic dynamics from data only, and physical modelling based on conservation laws. This enables the reservoir computing framework to output physical predictions when training data are unavailable. We show that the combination of the two approaches is able to accurately reproduce the velocity statistics, and to predict the occurrence and amplitude of extreme events in a model of self-sustaining process in turbulence. In this flow, the extreme events are abrupt transitions from turbulent to quasi-laminar states, which are deterministic phenomena that cannot be traditionally predicted because of chaos. Furthermore, the physics-constrained machine learning method is shown to be robust with respect to noise. This work opens up new possibilities for synergistically enhancing data-driven methods with physical knowledge for the time-accurate prediction of chaotic flows.

Effects of low-intensity electrical stimulation and adipose derived stem cells transplantation on the time-domain analysis-based electromyographic signals in dogs with SCI.

INTRODUCTION: The application of low-intensity electrical stimulation (LIES) to neural tissue increases neurochemical factors responsible for regeneration as nerve growth factor. Stem cell (SC) therapy for patients with Spinal cord injury (SCI) promote some increase functional improvement. OBJECTIVE: Investigate the electromyographic response in paraplegic dogs undergoing LIES and SC transplantation. METHODS: 27 dogs paraplegics with SCI were divided into three groups with different types of therapy. GADSC: two SC transplants (n = 9); GLIES: LIES (n = 8); GCOMB: two SC transplants and LIES (n = 10). Adipose derived mesenchymal stem cells (ADSCs) were transplanted by lumbar puncture in the amount of 1.2 × 106 cells/50 µL. Acupuncture needles positioned in the interspinous space were used for stimulation. The electrical stimulation was applied with a mean voltage ∼30 mV and four consecutive modulated frequencies (5 Hz, 10 Hz, 15 Hz and 20 Hz) within 5 min each. The patients motor performance was evaluated before (Pre) the procedure and after 30 (Post30) and 60 (Post60) days, from electromyography root mean square (EMGRMS) registered with subcutaneous electrodes in the vastus lateralis muscle, while the animals were in quadrupedal position. RESULTS: All three groups showed a significant intra-group increase of EMGRMS (Pre vs. Post30 or Pre vs. Post60). However, there were no statistically significant differences between Post30 and Post60. The inter-group test (GADSC X GLIES X GCOMB) did not present significance when compared the instants Pre (p = 0.34), Post30 (p = 0.78) and Post60 (p = 0.64). CONCLUSION: Some dogs recovered motor activity, expressed by the EMGRMS, in all groups, in pre vs. post (30 or 60 days) comparisons.

c-Myc-dependent transcriptional regulation of cell cycle and nucleosomal histones during oligodendrocyte differentiation.

Oligodendrocyte progenitor cells (OPCs) have the ability to divide or to growth arrest and differentiate into myelinating oligodendrocytes in the developing brain. Due to their high number and the persistence of their proliferative capacity in the adult brain, OPCs are being studied as potential targets for myelin repair and also as a potential source of brain tumors. This study addresses the molecular mechanisms regulating the transcriptional changes occurring at the critical transition between proliferation and cell cycle exit in cultured OPCs. Using bioinformatic analysis of existing datasets, we identified c-Myc as a key transcriptional regulator of this transition and confirmed direct binding of this transcription factor to identified target genes using chromatin immunoprecipitation. The expression of c-Myc was elevated in proliferating OPCs, where it also bound to the promoter of genes involved in cell cycle regulation (i.e. Cdc2) or chromosome organization (i.e. H2afz). Silencing of c-Myc was associated with decreased histone acetylation at target gene promoters and consequent decrease of gene transcripts. c-Myc silencing also induced a global increase of repressive histone methylation and premature peripheral nuclear chromatin compaction while promoting the progression towards differentiation. We conclude that c-Myc is an important modulator of the transition between proliferation and differentiation of OPCs, although its decrease is not sufficient to induce progression into a myelinating phenotype.

The association between insight and symptoms in bipolar inpatients: an Italian prospective study.

OBJECTIVE: To evaluate potential differences in insight among bipolar manic, mixed and bipolar depressed inpatients and assess the role of clinical and demographic characteristics as possible predictors. METHOD: One hundred and twenty consecutive inpatients divided into three diagnostic groups were studied on admission (T0), at discharge (T1) and at 18weeks after hospitalization (T2). The young mania rating scale (YMRS), the Hamilton rating scale for depression (HAMD) and the scale to assess unawareness of mental disorder (SUMD) were used. RESULTS: Patients with mixed mania showed highest scores on the SUMD than patients with mania or bipolar depression. It was found a significant relationship between improvements in mania and in the insight. The level of insight at baseline was the only predictor of awareness in social consequences, moreover clinical and demographic characteristics were predictors of insight into mental illness. For what concerns insight about therapy benefits it was influenced by level of mania at baseline. CONCLUSION: The three general dimensions of insight revealed significant differences among the three groups. Regression models suggest that insight is a multidimensional concept in which some aspects are state-related, associated with psychopathology, whereas others are trait-like qualities, not directly associated with symptoms and predicted only by level at baseline.

Role of estrogens in anterior pituitary gland remodeling during the estrous cycle.

In this review, we analyze the action of estrogens leading to the remodeling of the anterior pituitary gland, especially during the estrous cycle. Proliferation and death of anterior pituitary cells and especially lactotropes is regulated by estrogens, which act by sensitizing these cells to both mitotic and apoptotic stimuli such as TNF-alpha, FasL and dopamine. During the estrous cycle, the changing pattern of gonadal steroids is thought to modulate both cell proliferation and death in the anterior pituitary gland, estrogens being key players in cell turnover. The mechanisms involved in estrogen-modulated cell renewal in the anterior pituitary gland during the estrous cycle could include an increase in the expression of proapoptotic cytokines as well as the increase in the Bax/Bcl-2 ratio at proestrus, when estrogen levels are highest and a peak of apoptosis, in particular of lactotropes, is evident in this gland. Estrogens exert rapid antimitogenic and proapoptotic actions in the anterior pituitary through membrane-associated estrogen receptors, a mechanism that might also be involved in remodeling of this gland during the estrous cycle.

A symptom-specific analysis of the effect of high-frequency left or low-frequency right transcranial magnetic stimulation over the dorsolateral prefrontal cortex in major depression.

BACKGROUND: We have investigated the efficacy of high-frequency left (HFL) versus low-frequency right (LFR) repetitive transcranial magnetic stimulation (rTMS) in depression, focusing on specific symptoms as possible predictors of outcome for these two different types of stimulation. METHOD: Seventy-four outpatients with a major depressive episode treated with an adequate antidepressant dosage for at least 4 weeks were included in our study and randomly assigned to two different groups: HFL or LFR rTMS. The Hamilton Rating Scale for Depression (HAM-D) items were pooled into 6 factors to evaluate specific symptoms as possible predictors of response. RESULTS: Twenty-one out of 32 patients (65.6%) and 24 out of 42 patients (57.1%) were responders in the HFL and LFR groups, respectively. No significant difference in response rate was observed. Considering the whole sample, we found an inverse correlation between activity and HAM-D score reduction and a significant positive relation between somatic anxiety and outcome. An inverse correlation between psychic anxiety and HAM-D score reduction emerged considering the HFL group. In the LFR group, there was a significant negative relationship between baseline activity and the outcome. CONCLUSION: These findings support the hypothesis that LFR rTMS could be as effective as HFL rTMS and more suitable for patients with a higher anxiety degree, particularly in bipolar patients.

Response to SSRIs and role of the hormonal therapy in post-menopausal depression.

The aim of this study is to prospectively evaluate the antidepressant response to SSRIs in depressed post-menopausal women with or without hormonal therapy (HT), and to analyze the possible influence of basal serum levels of gonadotropins and sexual hormones on the antidepressant response. 170 post-menopausal women with a depressive episode (DSM-IV criteria)--47 on HT and 123 not on HT--started the treatment with an SSRI. Depressive symptoms were assessed at baseline and 7 weeks thereafter by raters blind to treatment regimen. Response rates were 63.2% in the group without HT and 83.7% in the HT group (p=0.013). An inverse correlation emerged between the basal levels of LH and the improvement in HRSD scores (p=0.001) in the group without HT. In conclusion, HT appeared to improve the antidepressant response to SSRIs. Furthermore, in post-menopausal women, LH basal levels may be taken into account as possible predictor of response.