2,120 research outputs found
Controlling selectivity in alkene oxidation : anion driven syn-dihydroxylation or epoxidation catalysed by [Iron(III)(Pyridine-Containing Ligand)] complexes
The introduction of a pyridine moiety into the skeleton of a polyazamacrocyclic ligand affects both thermodynamic properties and coordination kinetics of the resulting metal complexes.1 These features have engendered a great interest of the scientific community. Much of the efforts in the use of macrocyclic pyridine containing ligands have been devoted to the study of catalytic oxidation reactions.2 We report here the synthesis and characterisation of [Fe(III)Pc-L\u2019s)] complexes (Pc-L = Pyridine-Containing Ligand) and their catalytic applications in alkene oxidation reactions using H2O2 as the terminal oxidant under mild conditions (Figure). Depending on the anion employed for the synthesis of the iron(III) metal complex, we observed a completely reversed selectivity. When X = OTf, a selective syn-dihydroxylation reaction was observed. On the other hand, employing X = Cl, we obtained the epoxide as the major product. It should be pointed out that under otherwise identical reaction conditions, using FeCl3\ub76H2O as catalyst in the absence of the ligand, no reaction was observed
Deuteration as an evolutionary tracer in massive-star formation
Theory predicts, and observations confirm, that the column density ratio of a
molecule containing D to its counterpart containing H can be used as an
evolutionary tracer in the low-mass star formation process. Since it remains
unclear if the high-mass star formation process is a scaled-up version of the
low-mass one, we investigated whether the relation between deuteration and
evolution can be applied to the high-mass regime. With the IRAM-30m telescope,
we observed rotational transitions of N2D+ and N2H+ and derived the deuterated
fraction in 27 cores within massive star-forming regions understood to
represent different evolutionary stages of the massive-star formation process.
Results. Our results clearly indicate that the abundance of N2D+ is higher at
the pre-stellar/cluster stage, then drops during the formation of the
protostellar object(s) as in the low-mass regime, remaining relatively constant
during the ultra-compact HII region phase. The objects with the highest
fractional abundance of N2D+ are starless cores with properties very similar to
typical pre-stellar cores of lower mass. The abundance of N2D+ is lower in
objects with higher gas temperatures as in the low-mass case but does not seem
to depend on gas turbulence. Our results indicate that the N2D+-to-N2H+ column
density ratio can be used as an evolutionary indicator in both low- and
high-mass star formation, and that the physical conditions influencing the
abundance of deuterated species likely evolve similarly during the processes
that lead to the formation of both low- and high-mass stars.Comment: Accepted by A&AL, 4 pages, 2 figures, 2 appendices (one for Tables,
one for additional figures
A systematic review of the relationship between generic and specific metacognitive beliefs and emotion dysregulation: A metacognitive model of emotion dysregulation
Although a probable association between metacognitive beliefs (also termed âmetacognitionsâ) and emotion dysregulation has been suggested in the literature, the evidence is still sparse and inconclusive. The current study aims to present a comprehensive evaluation of the literature examining the association between metacognitive beliefs and emotion dysregulation. In accordance with Preferred Reporting Items for Systematic Reviews and MetaâAnalyses (PRISMA) criteria, a search was conducted on PubMed and Ebsco. A manual search of reference lists was also run. Search terms were âmetacognitions/metacognitive beliefs/positive metacognitive beliefs/negative metacognitive beliefs/cognitive selfâconsciousness/beliefs about the need to control thoughts/cognitive confidence/negative beliefs about thoughts concerning uncontrollability and danger/AND difficulties emotion regulation/emotion dysregulationâ. A total of 19 studies met the inclusion criteria. In both nonâclinical and clinical populations, a higher endorsement of dysfunctional metacognitive beliefs was found to be associated with emotion dysregulation and vice versa. A higher endorsement of metacognitive beliefs may be associated, either directly or via maladaptive forms of mental control (e.g., worry, rumination and suppression) to emotion dysregulation. Metacognitive beliefs could be the potential therapeutic target in clinical interventions aimed at reducing emotion regulation difficulties
Metacognitions about desire thinking predict the severity of binge eating in a sample of Italian women
In this study, our principal aim was to investigate whether metacognitions about desire thinking predict the severity of binge eating in women and, if so, whether this relationship is independent of age, self-reported body mass index (BMI), negative affect, irrational food beliefs and craving. One hundred and four women, consisting of 32 consecutive patients with binge eating disorder undergoing initial assessment for cognitive therapy for eating disorders, 39 moderate binge eaters, and 33 non-binge eaters (both from the general population), completed the following measures: Self-reported BMI, Hospital Anxiety and Depression Scale, Irrational Food Beliefs Scale, General Craving Scale, Metacognitions about Desire Thinking Questionnaire, and Binge Eating Scale. A series of Spearman's rho correlation analyses revealed that self-reported BMI, anxiety, depression, irrational food beliefs, craving, and all three factors of the metacognitions about desire thinking questionnaire were significantly associated with the severity of binge eating. A stepwise regression analysis identified self-reported BMI, craving, and negative metacognitions about desire thinking as significant predictors of the severity of binge eating. These results, taken together, highlight the possible role of metacognitions about desire thinking in predicting the severity of binge eating. The clinical implications of these findings are discussed
First detection of triply-deuterated methanol
We report the first detection of triply-deuterated methanol, with 12 observed
transitions, towards the low-mass protostar IRAS 16293-2422, as well as
multifrequency observations of 13CH3OH, used to derive the column density of
the main isotopomer CH3OH. The derived fractionation ratio [CD3OH]/[CH3OH]
averaged on a 10'' beam is 1.4%. Together with previous CH2DOH and CHD2OH
observations, the present CD3OH observations are consistent with a formation of
methanol on grain surfaces, if the atomic D/H ratio is 0.1 to 0.3 in the
accreting gas. Such a high atomic ratio can be reached in the frame of
gas-phase chemical models including all deuterated isotopomers of H3+.Comment: Accepted by A&
Personality, motives and metacognitions as predictors of problematic Facebook Use in university students
© 2016 Elsevier Ltd.Facebook has become hugely popular among young people and adults all over the world, creating a new social phenomenon that has affected the communication patterns used by people to interact with each other. Although most people use Facebook wisely, a minority of users can show negative patterns of Facebook use, with negative consequences on personal psycho-social well-being, especially among young adults. The present study aims to test a model designed to assess the unique contribution of personality traits, motives for using Facebook and metacognitions on Problematic Facebook Use (PFU) among young adults. A total of 815 Italian university students participated in the study. Path analysis revealed that three of the four motives to use Facebook, and that two of the five metacognitions, predicted PFU. Moreover, only one personality trait (extraversion) appeared to be directly linked to PFU, while emotional stability indirectly influenced PFU via motives (coping and conformity) and metacognitions (negative beliefs about worry and cognitive confidence). In conclusion, motives and metacognitions predict PFU among young adults, and they should be taken into account to develop preventive measures and clinical interventions
Diagnosing shock temperature with NH and HO profiles
In a previous study of the L1157 B1 shocked cavity, a comparison between
NH(1-) and HO(1--1) transitions showed a
striking difference in the profiles, with HO emitting at definitely higher
velocities. This behaviour was explained as a result of the high-temperature
gas-phase chemistry occurring in the postshock gas in the B1 cavity of this
outflow. If the differences in behaviour between ammonia and water are indeed a
consequence of the high gas temperatures reached during the passage of a shock,
then one should find such differences to be ubiquitous among chemically rich
outflows. In order to determine whether the difference in profiles observed
between NH and HO is unique to L1157 or a common characteristic of
chemically rich outflows, we have performed Herschel-HIFI observations of the
NH(1-0) line at 572.5 GHz in a sample of 8 bright low-mass outflow
spots already observed in the HO(1--1) line within
the WISH KP. We detected the ammonia emission at high-velocities at most of the
outflows positions. In all cases, the water emission reaches higher velocities
than NH, proving that this behaviour is not exclusive of the L1157-B1
position. Comparisons with a gas-grain chemical and shock model confirms, for
this larger sample, that the behaviour of ammonia is determined principally by
the temperature of the gas.Comment: Accepted for publication in the Monthly Notices of the Royal
Astronomical Societ
Emotion regulation and desire thinking as predictors of problematic Facebook use
Background: Research evidence suggests that problematic Facebook use (PFU) affects large numbers of people worldwide. A variety of studies have investigated the relationship between PFU and psychological dysfunction, revealing that negative mood and cognitive self-regulation are common among problematic Facebook users.
Aim: The aim of the present study was to examine the role of craving, emotion regulation and desire thinking in predicting PFU.
Methods: An online survey was administered to 750 participants (males = 82%; Mage = 23.38 years; SDage = 5.72). Correlation analyses were conducted in order to test the associations between emotion regulation, craving, desire thinking and PFU. A path analysis was run to model the inter-relationships between the variables based on previous research findings.
Results: Correlation analyses indicated that all predictor variables were positively associated with PFU. Path analysis showed that imaginal prefiguration was associated with craving, which, in turn, was associated with verbal prefiguration that was directly linked to PFU, beyond the direct effect of emotion regulation.
Conclusions: These findings provide further support for the importance of desire thinking in predicting problematic behaviours. Desire thinking and emotion regulation should be considered in the modification of problematic Facebook use
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