GSK-3ß orchestrates the inhibitory innervation of adult-born dentate granule cells in vivo.

Adult hippocampal neurogenesis enhances brain plasticity and contributes to the cognitive reserve during aging. Adult hippocampal neurogenesis is impaired in neurological disorders, yet the molecular mechanisms regulating the maturation and synaptic integration of new neurons have not been fully elucidated. GABA is a master regulator of adult and developmental neurogenesis. Here we engineered a novel retrovirus encoding the fusion protein Gephyrin:GFP to longitudinally study the formation and maturation of inhibitory synapses during adult hippocampal neurogenesis in vivo. Our data reveal the early assembly of inhibitory postsynaptic densities at 1 week of cell age. Glycogen synthase kinase 3 Beta (GSK-3ß) emerges as a key regulator of inhibitory synapse formation and maturation during adult hippocampal neurogenesis. GSK-3ß-overexpressing newborn neurons show an increased number and altered size of Gephyrin+ postsynaptic clusters, enhanced miniature inhibitory postsynaptic currents, shorter and distanced axon initial segments, reduced synaptic output at the CA3 and CA2 hippocampal regions, and impaired pattern separation. Moreover, GSK-3ß overexpression triggers a depletion of Parvalbumin+ interneuron perineuronal nets. These alterations might be relevant in the context of neurological diseases in which the activity of GSK-3ß is dysregulated.

Long-term outcome predictors after functional remediation in patients with bipolar disorder.

BACKGROUND: Improving functioning in patients with bipolar disorder (BD) is one of the main objectives in clinical practice. Of the few psychosocial interventions that have been specifically developed to enhance the psychosocial outcome in BD, functional remediation (FR) is one which has demonstrated efficacy. The aim of this study was to examine which variables could predict improved functional outcome following the FR intervention in a sample of euthymic or subsyndromal patients with BD. METHODS: A total of 92 euthymic outpatients were included in this longitudinal study, with 62 completers. Partial correlations controlling for the functional outcome at baseline were calculated between demographic, clinical and neurocognitive variables, and functional outcome at endpoint was assessed by means of the Functioning Assessment Short Test scale. Next, a multiple regression analysis was run in order to identify potential predictors of functional outcome at 2-year follow-up, using the variables found to be statistically significant in the correlation analysis and other variables related to functioning as identified in the previous scientific literature. RESULTS: The regression model revealed that only two independent variables significantly contributed to the model (F(6,53): 4.003; p = 0.002), namely verbal memory and inhibitory control. The model accounted for 31.2% of the variance. No other demographic or clinical variable contributed to the model. CONCLUSIONS: Results suggest that patients with better cognitive performance at baseline, especially in terms of verbal memory and executive functions, may present better functional outcomes at long term follow-up after receiving functional remediation.

Identifying social cognition subgroups in euthymic patients with bipolar disorder: a cluster analytical approach.

BACKGROUND: Bipolar disorder (BD) is associated with social cognition (SC) impairments even during remission periods although a large heterogeneity has been described. Our aim was to explore the existence of different profiles on SC in euthymic patients with BD, and further explore the potential impact of distinct variables on SC. METHODS: Hierarchical cluster analysis was conducted using three SC domains [Theory of Mind (ToM), Emotional Intelligence (EI) and Attributional Bias (AB)]. The sample comprised of 131 individuals, 71 patients with BD and 60 healthy control subjects who were compared in terms of SC performance, demographic, clinical, and neurocognitive variables. A logistic regression model was used to estimate the effect of SC-associated risk factors. RESULTS: A two-cluster solution was identified with an adjusted-performance group (N = 48, 67.6%) and a low-performance group (N = 23, 32.4%) with mild deficits in ToM and AB domains and with moderate difficulties in EI. Patients with low SC performance were mostly males, showed lower estimated IQ, higher subthreshold depressive symptoms, longer illness duration, and poorer visual memory and attention. Low estimated IQ (OR 0.920, 95% CI 0.863-0.981), male gender (OR 5.661, 95% CI 1.473-21.762), and longer illness duration (OR 1.085, 95% CI 1.006-1.171) contributed the most to the patients clustering. The model explained up to 35% of the variance in SC performance. CONCLUSIONS: Our results confirmed the existence of two discrete profiles of SC among BD. Nearly two-thirds of patients exhibited adjusted social cognitive abilities. Longer illness duration, male gender, and lower estimated IQ were associated with low SC performance.

Multicenter Retrospective Registry of Anterior Communicating Artery Aneurysms with Endovascular Therapy (MACAARET): safety and efficacy study according to morphological considerations and spatial orientations.

AIM: To analyse the safety and efficacy parameters of endovascular treatment of anterior communicating artery (ACoA) aneurysms, according to their morphological considerations and three-dimensional orientation in a multicentric registry. MATERIALS AND METHODS: A retrospective analysis was undertaken of a prospective database of consecutive patients that underwent endovascular embolisation for ACoA aneurysm in four high-volume neuroradiology interventional departments. The study has been registered in ClinicalTrial.gov. Data were collected regarding the clinico-demographic variables of the patients, anatomical variations of the circle of Willis, morphological considerations and spatial orientation of ACoA aneurysms were recorded. Safety and efficacy variables were also recorded. Associations between anatomical variations of the circle of Willis, morphological considerations, and spatial orientation of the ACoA aneurysms and safety and efficacy variables were assessed. RESULTS: Data from 122 consecutive patients were collected in the MACAARET study (mean age (±SD) was 55 (±14) and 50.8% (62/122) were male). One hundred and five patients (86.1%) presented with subarachnoid haemorrhage (SAH). ACoA aneurysms with a neck size of >4 mm had less chance of having successful endovascular treatment than those of ≤4 mm (19.8% versus 46.7%; p=0.002) and were also more likely to recanalise during follow-up (61.5% versus 19.5%; p=0.003). Moreover, ACoA aneurysms with an aspect ratio of >1.7 had more chance of having immediate therapeutic success than those with a ratio of ≤1.7 (70.7% versus 44.8%; p=0.012). There were no other associations between the anatomical variables of the ACoA aneurysms and the safety-efficacy variables. CONCLUSION: ACoA aneurysms are suitable for both endovascular and microsurgical approaches, but more data are required to determine which is the best approach regarding the morphological and spatial orientation of the aneurysm and the anatomical variations of the circle of Willis.

The impact of water vapor on the OH reactivity toward CH3CHO at ultra-low temperatures (21.7-135.0 K): Experiments and theory.

The role of water vapor (H2O) and its hydrogen-bonded complexes in the gas-phase reactivity of organic compounds with hydroxyl (OH) radicals has been the subject of many recent studies. Contradictory effects have been reported at temperatures between 200 and 400 K. For the OH + acetaldehyde reaction, a slight catalytic effect of H2O was previously reported at temperatures between 60 and 118 K. In this work, we used Laval nozzle expansions to reinvestigate the impact of H2O on the OH-reactivity with acetaldehyde between 21.7 and 135.0 K. The results of this comprehensive study demonstrate that water, instead, slows down the reaction by factors of ∼3 (21.7 K) and ∼2 (36.2-89.5 K), and almost no effect of added H2O was observed at 135.0 K.

Inoculation with rumen fluid in early life as a strategy to optimize the weaning process in intensive dairy goat systems.

Ruminants are born with an undeveloped physical, metabolic, and microbial rumen. Rumen development is limited under artificial rearing systems when newborn animals are separated from the dam, fed on milk replacer, and weaned at an early age. This study aims to evaluate the effects of early-life inoculation of young ruminants with rumen fluid from adult animals. Eighty newborn goat kids were randomly allocated to 1 of 4 experimental treatments and inoculated daily from d 1 to wk 11 with autoclaved rumen fluid (AUT), fresh rumen fluid obtained from adult goats fed either a forage diet (RFF) or concentrate-rich diet (RFC), or absence of inoculation (CTL). Goat kids were artificially reared with ad libitum access to milk replacer, starter concentrate, and forage hay. Blood was sampled weekly and rumen microbial fermentation was monitored at 5 (preweaning), 7 (weaning), and 9 wk of age (postweaning). Results indicated that inoculation with fresh rumen fluid accelerated the rumen microbial and fermentative development before weaning. As a result, RFC and RFF animals had higher solid feed intake (+73%), rumen concentrations of ammonia-N (+26%), total volatile fatty acids (+46%), butyrate (+50%), and plasma ß-hydroxybutyrate (+48%), and lower milk intake (-6%) than CTL and AUT animals at wk 5. Inoculation with fresh inoculum also promoted early rumen colonization by a complex and abundant protozoal community, whereas CTL animals remained protozoa free. Although all kids experienced moderate growth retardation during 1 wk after weaning, inoculation with fresh rumen fluid favored the weaning process, leading to 2.2 times higher weight gain than CTL and AUT animals during wk 8. Some of these advantages were retained during the postweaning period and RFF and RFC animals showed higher forage intake (up to +44%) than CTL and AUT animals with no detrimental effects on feed digestibility or stress levels. The superior microbial load of RFC compared with RFF inoculum tended to provide further improvements in terms of forage intake, plasma ß-hydroxybutyrate, and rumen protozoa, whereas AUT inoculation provided minor (if any) advantages with respect to CTL animals. Although no differences were noted on animal growth, this study suggests that early life inoculation of goat kids with rumen microbiota can represent an effective strategy to accelerate the rumen development, facilitating a smooth transition from milk to solid feed and to the potential implementation of early weaning strategies.

Cortical abnormalities in bipolar disorder: an MRI analysis of 6503 individuals from the ENIGMA Bipolar Disorder Working Group.

Despite decades of research, the pathophysiology of bipolar disorder (BD) is still not well understood. Structural brain differences have been associated with BD, but results from neuroimaging studies have been inconsistent. To address this, we performed the largest study to date of cortical gray matter thickness and surface area measures from brain magnetic resonance imaging scans of 6503 individuals including 1837 unrelated adults with BD and 2582 unrelated healthy controls for group differences while also examining the effects of commonly prescribed medications, age of illness onset, history of psychosis, mood state, age and sex differences on cortical regions. In BD, cortical gray matter was thinner in frontal, temporal and parietal regions of both brain hemispheres. BD had the strongest effects on left pars opercularis (Cohen's d=-0.293; P=1.71 × 10-21), left fusiform gyrus (d=-0.288; P=8.25 × 10-21) and left rostral middle frontal cortex (d=-0.276; P=2.99 × 10-19). Longer duration of illness (after accounting for age at the time of scanning) was associated with reduced cortical thickness in frontal, medial parietal and occipital regions. We found that several commonly prescribed medications, including lithium, antiepileptic and antipsychotic treatment showed significant associations with cortical thickness and surface area, even after accounting for patients who received multiple medications. We found evidence of reduced cortical surface area associated with a history of psychosis but no associations with mood state at the time of scanning. Our analysis revealed previously undetected associations and provides an extensive analysis of potential confounding variables in neuroimaging studies of BD.

Social cognition in bipolar disorder: the role of sociodemographic, clinical, and neurocognitive variables in emotional intelligence.

OBJECTIVE: The main aims of this study were to examine the differences in the Emotional Intelligence (EI), the emotional domain of social cognition (SC), between euthymic patients with bipolar disorder (BD) and healthy controls (HC) and to evaluate the contribution of sociodemographic, clinical, and neuropsychological variables to EI. METHODS: We recruited 202 patients with BD and 50 HC. EI was evaluated using the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT). The sociodemographic, clinical, and neurocognitive variables that showed a significant association with EI were entered into hierarchical multiple regression analysis. RESULTS: BD patients obtained significantly lower scores compared to HC in the Emotional Intelligence Quotient (EIQ) and in the Understanding Emotions branch score. The best fitting model for the variables associated with EI in the patients group was a linear combination of gender, estimated IQ, family history of affective diagnosis, and executive function. The model, including these previous variables, explained up to 27.6% of the observed variance (R2  = 0.276, F = 16.406, P < 0.001). CONCLUSIONS: The identification of variables associated with deficit in EI, such as male gender, lower estimated IQ, family history of affective diagnosis. and lower executive function performance, may help in selecting treatment targets to improve SC, and especially EI, in patients with BD.

Heterogeneity of functional outcomes in patients with bipolar disorder: a cluster-analytic approach.

OBJECTIVE: The aim was to examine the heterogeneity of psychosocial outcomes in euthymic bipolar disorder (BD) patients and analyse the potential influence of distinct variables on functioning. METHOD: Using a hierarchical cluster exploratory analysis, 143 euthymic patients with diagnosis of BD were grouped according to their functional performance based on domains scores of the Functioning Assessment Short Test (FAST). The resulting groups were compared on sociodemographic, clinical and neurocognitive variables to find factors associated with each functional cluster. RESULTS: Patients were grouped in three functional profiles: patients with good functioning in all the FAST areas, patients with an intermediate profile showing great difficulties in the occupational domain and milder difficulties in most of the rest domains, and a third group with serious difficulties in almost all functional areas. Both functionally impaired groups were characterized by higher subthreshold symptoms (depressive and manic) and higher unemployment rates. The most functionally impaired group also showed lower scores on some measures of processing speed. CONCLUSION: Two of three functional profiles showed some kind of impairment which was associated with subsyndromal symptoms and cognitive performance. These patterns should be taken into consideration to develop more individualized interventions to restore, or improve, psychosocial outcomes.

Factors associated with poor functional outcome in bipolar disorder: sociodemographic, clinical, and neurocognitive variables.

OBJECTIVE: The current investigation aimed at studying the sociodemographic, clinical, and neuropsychological variables related to functional outcome in a sample of euthymic patients with bipolar disorder(BD) presenting moderate-severe levels of functional impairment. METHODS: Two-hundred and thirty-nine participants with BD disorders and with Functioning Assessment Short Test(FAST) scores equal or above 18 were administered a clinical and diagnostic interview, and the administration of mood measure scales and a comprehensive neuropsychological battery. Analyses involved preliminary Pearson bivariate correlations to identify sociodemographic and clinical variables associated with the FAST total score. Regarding neuropsychological variables, a principal component analysis (PCA) was performed to group the variables in orthogonal factors. Finally, a hierarchical multiple regression was run. RESULTS: The best fitting model for the variables associated with functioning was a linear combination of gender, age, estimated IQ, Hamilton Depression Rating Scale (HAM-D), number of previous manic episodes, Factor 1 and Factor 2 extracted from the PCA. The model, including all these previous variables, explained up to 29.4% of the observed variance. CONCLUSIONS: Male gender, older age, lower premorbid IQ, subdepressive symptoms, higher number of manic episodes, and lower performance in verbal memory, working memory, verbal fluency, and processing speed were associated with lower functioning in patients with BD.

Gas phase kinetics of the OH + CH3CH2OH reaction at temperatures of the interstellar medium (T = 21-107 K).

Ethanol, CH3CH2OH, has been unveiled in the interstellar medium (ISM) by radioastronomy and it is thought to be released into the gas phase after the warm-up phase of the grain surface, where it is formed. Once in the gas phase, it can be destroyed by different reactions with atomic and radical species, such as hydroxyl (OH) radicals. The knowledge of the rate coefficients of all these processes at temperatures of the ISM is essential in the accurate interpretation of the observed abundances. In this work, we have determined the rate coefficient for the reaction of OH with CH3CH2OH (k(T)) between 21 and 107 K by employing the pulsed and continuous CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme, which means Reaction Kinetics in a Uniform Supersonic Flow) technique. The pulsed laser photolysis technique was used for generating OH radicals, whose time evolution was monitored by laser induced fluorescence. An increase of approximately 4 times was observed for k(21 K) with respect to k(107 K). With respect to k(300 K), the OH-reactivity at 21 K is enhanced by two orders of magnitude. The obtained T-expression in the investigated temperature range is k(T) = (2.1 ± 0.5) × 10-11 (T/300 K)-(0.71±0.10) cm3 molecule-1 s-1. In addition, the pressure dependence of k(T) has been investigated at several temperatures between 21 K and 90 K. No pressure dependence of k(T) was observed in the investigated ranges. This may imply that this reaction is purely bimolecular or that the high-pressure limit is reached at the lowest total pressure experimentally accessible in our system. From our results, k(T) at usual IS temperatures (∼10-100 K) is confirmed to be very fast. Typical rate coefficients can be considered to range within about 4 × 10-11 cm3 molecule-1 s-1 at 100 K and around 1 × 10-10 cm3 molecule-1 s-1 at 20 K. The extrapolation of k at the lowest temperatures of the dense molecular clouds of ISM is also discussed in this paper.

Comment on "Methanol dimer formation drastically enhances hydrogen abstraction from methanol by OH at low temperature" by W. Siebrand, Z. Smedarchina, E. Martínez-Núñez and A. Fernández-Ramos, Phys. Chem. Chem. Phys., 2016, 18, 22712.

The article "Methanol dimer formation drastically enhances hydrogen abstraction from methanol by OH at low temperature" proposes a dimer mediated mechanism in order to explain the large low temperature rate coefficients for the OH + methanol reaction measured by several groups. It is demonstrated here theoretically that under the conditions of these low temperature experiments, there are insufficient dimers formed for the proposed new mechanism to apply. Experimental evidence is also presented to show that dimerization of the methanol reagent does not influence the rate coefficients reported under the conditions of methanol concentration used for the kinetics studies. It is also emphasised that the low temperature experiments have been performed using both the Laval nozzle expansion and flow-tube methods, with good agreement found for the rate coefficients measured using these two distinct techniques.

Effect of feeding a high-carbohydrate or a high-fat diet on subsequent food intake and blood concentration of satiety-related hormones in dogs.

Although studies in rodents and humans have evidenced a weaker effect of fat in comparison to carbohydrates on the suppression of food intake, very few studies have been carried out in this field in dogs. This study investigates the effects of a high-carbohydrate (HC) and a high-fat (HF) diets on subsequent food intake and blood satiety-related hormones in dogs. Diets differed mainly in their starch (442 vs. 271 g/kg dry matter) and fat (99.3 vs. 214 g/kg dry matter) contents. Twelve Beagle dogs received the experimental diets at maintenance energy requirements in two experimental periods, following a cross-over arrangement. In week 7 of each period, blood concentrations of active ghrelin, glucagon-like peptide (GLP-1), peptide YY, insulin, and glucose were determined before and at 30, 60, 120, 180, and 360 min post-feeding. The following week, intake of a challenge food offered 180 min after the HC and HF diets was recorded over two days. In comparison to the dogs on the HC diet, those on the HF diet had a higher basal concentration of GLP-1 (p = .010) and a higher total area under the curve over 180 min post-prandial (tAUC0-180 ) (p = .031). Dogs on the HC diet showed a higher elevation of ghrelin at 180 min (p = .033) and of insulin at 360 min (p = .041), although ghrelin and insulin tAUC0-180 did not differ between the two diets (p Ëƒ .10). Diet had no effect on challenge food intake (p Ëƒ .10), which correlated with the tAUC0-180 of ghrelin (r = .514, p = .010), insulin (r = -.595, p = .002), and glucose (r = -.516, p = .010). Feeding a diet high in carbohydrate or fat at these inclusion levels does not affect the feeding response at 180 min post-prandial, suggesting a similar short-term satiating capacity.

A comparative study on the influence of different organic amendments on trace element mobility and microbial functionality of a polluted mine soil.

A mine soil heavily polluted with zinc and cadmium was employed to evaluate the capacity of organic amendments of different origin to simultaneously reduce soil trace element mobility and enhance soil microbial functionality. With this aim, four organic products, namely olive processing solid waste (OPSW), municipal solid waste compost (MSWC), leonardite and peat, were applied individually at different doses (0, 1, 2 and 5%) to mine soil under controlled laboratory conditions. Extraction studies and analysis of soil microbiological parameters (basal soil respiration and dehydrogenase, ß-glucosidase, urease, arylsulfatase and acid and alkaline phosphatase activities) were performed to assess the effect of such amendments on soil restoration. Their ability to decrease mine soil mobile trace element contents followed the sequence MSWC > OPSW > peat > leonardite, with the former achieving reduction levels of 78 and 73% for Zn and Cd, respectively, when applied at a dose of 5%. This amendment also showed a good performance to restore soil microbial functionality. Thus, basal soil respiration and dehydrogenase, urease and alkaline phosphatase activities experienced increases of 187, 79, 42 and 26%, respectively, when mine soil was treated with 5% MSWC. Among tested organic products, MSWC proved to be the best amendment to perform both the chemical and the microbial soil remediation.

Evidence-based guides in tracheostomy use in critical patients. / Guías basadas en la evidencia para el uso de traqueostomía en el paciente crítico.

OBJECTIVES: Provide evidence based guidelines for tracheostomy in critically ill adult patients and identify areas needing further research. METHODS: A task force composed of representatives of 10 member countries of the Pan-American and Iberic Federation of Societies of Critical and Intensive Therapy Medicine and of the Latin American Critical Care Trial Investigators Network developed recommendations based on the Grading of Recommendations Assessment, Development and Evaluation system. RESULTS: The group identified 23 relevant questions among 87 issues that were initially identified. In the initial search, 333 relevant publications were identified of which 226 publications were chosen. The task force generated a total of 19 recommendations: 10 positive (1B=3, 2C=3, 2D=4) and 9 negative (1B=8, 2C=1). A recommendation was not possible in six questions. CONCLUSION: Percutaneous techniques are associated with a lower risk of infections compared to surgical tracheostomy. Early tracheostomy only seems to reduce the duration of ventilator use but not the incidence of pneumonia, the length of stay, or the long-term mortality rate. The evidence does not support the use of routine bronchoscopy guidance or laryngeal masks during the procedure. Finally, proper prior training is as important or even a more significant factor in reducing complications than the technique used.

The high-field magnet endstation for X-ray magnetic dichroism experiments at ESRF soft X-ray beamline ID32.

A new high-field magnet endstation for X-ray magnetic dichroism experiments has been installed and commissioned at the ESRF soft X-ray beamline ID32. The magnet consists of two split-pairs of superconducting coils which can generate up to 9 T along the beam and up to 4 T orthogonal to the beam. It is connected to a cluster of ultra-high-vacuum chambers that offer a comprehensive set of surface preparation and characterization techniques. The endstation and the beam properties have been designed to provide optimum experimental conditions for X-ray magnetic linear and circular dichroism experiments in the soft X-ray range between 400 and 1600 eV photon energy. User operation started in November 2014.

Prepulse inhibition in euthymic bipolar disorder patients in comparison with control subjects.

OBJECTIVE: Deficient prepulse inhibition (PPI) of the startle response, indicating sensorimotor gating deficits, has been reported in schizophrenia and other neuropsychiatric disorders. This study aimed to assess sensorimotor gating deficits in patients with euthymic bipolar. Furthermore, we analysed the relationships between PPI and clinical and cognitive measures. METHOD: Prepulse inhibition was measured in 64 patients with euthymic bipolar and in 64 control subjects matched for age, gender, education level and smoking status. Clinical characteristics and level of functioning were assessed in all participants using Hamilton Depression Rating Scale (HDRS), Young Mania Rating Scale (YMRS) and Functioning Assessment Short Test (FAST). Cognition was evaluated using the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB) and the Stroop test as an additional measure of executive function. RESULTS: Compared with controls, patients with bipolar disorder exhibited PPI deficits at 60- and 120-millisecond prepulse-pulse intervals. Among patients with bipolar disorder, PPI was correlated with the social cognition domain of the MCCB. PPI was not significantly correlated with other clinical, functional and neurocognitive variables in either group. CONCLUSIONS: Our data suggest that PPI deficit is a neurobiological marker in euthymic bipolar disorder, which is associated with social cognition but not with other clinical, functional or cognitive measures.

Clinical features, impulsivity, temperament and functioning and their role in suicidality in patients with bipolar disorder.

OBJECTIVE: Our aim was to analyse sociodemographic and clinical differences between non-suicidal (NS) bipolar patients (BP), BP reporting only suicidal ideation (SI) and BP suicide attempters according to Columbia-Suicide Severity Rating Scale (C-SRSS) criteria. Secondarily, we also investigated whether the C-SRSS Intensity Scale was associated with emergence of suicidal behaviour (SB). METHOD: A total of 215 euthymic bipolar out-patients were recruited. Semistructured interviews including the C-SRSS were used to assess sociodemographic and clinical data. Patients were grouped according to C-SRSS criteria: patients who scored ≤1 on the Severity Scale were classified as NS. The remaining patients were grouped into two groups: 'patients with history of SI' and 'patients with history of SI and SB' according to whether they did or did not have a past actual suicide attempt respectively. RESULTS: Patients from the three groups differed in illness onset, diagnosis, number of episodes and admissions, family history, comorbidities, rapid cycling and medication, as well as level of education, functioning, impulsivity and temperamental profile. CONCLUSION: Our results suggest that increased impulsivity, higher rates of psychiatric admissions and a reported poor controllability of SI significantly increased the risk for suicidal acts among patients presenting SI.

First evidence of the dramatic enhancement of the reactivity of methyl formate (HC(O)OCH3) with OH at temperatures of the interstellar medium: a gas-phase kinetic study between 22 K and 64 K.

The gas phase chemistry of neutral-neutral reactions of interest in the interstellar medium (ISM) is poorly understood. The rate coefficients (kOH) for the majority of the reactions of hydroxyl (OH) radicals with interstellar oxygenated species are unknown at the temperatures of the ISM. In this study, we present the first determination of kOH for HC(O)OCH3 between 22.4 ± 1.4 and 64.2 ± 1.7 K. The CRESU (French acronym for Cinétique de Réaction en Ecoulement Supersonique Uniforme or Reaction Kinetics in a Uniform Supersonic Flow) technique was used to create a chemical reactor with a uniform temperature and gas density and the pulsed laser photolysis/laser induced fluorescence technique was used to generate OH radicals and to monitor their temporal profile. It was observed that kOH(T) increases by one order of magnitude in only ∼40 K (kOH(T = 22 K) = (1.19 ± 0.36) × 10(-10) cm(3) s(-1) and kOH(T = 64 K) = (1.16 ± 0.12) × 10(-11) cm(3) s(-1)) and ∼3 orders of magnitude with respect to kOH(T = 298 K). This reaction is a very efficient route for the loss of HC(O)OCH3 in the gas phase and may have a great impact on the interpretation of astrophysical models of HC(O)OCH3 abundance in the cold regions of the ISM.