Tetramesitylgermasilene: Synthesis And Reactivity Of A Germanium-silicon Double Bond

This thesis describes the synthesis of tetramesitylgermasilene (Mesityl=2,4,6-trimethylphenyl), the first example of a compound containing a germanium-silicon double bond, from hexamesitylsiladigermirane, the first compound containing a three-membered ring composed of two germanium atoms and one silicon atom. The synthesis can be effected both thermochemically and photochemically; however, the germasilene can only be characterized in solution at {dollar}{lcub}-78{rcub}\sp\circ{dollar}C.;In addition, a remarkable 1,2-mesityl rearrangement of the germasilene to form a silylgermylene is reported, with discussion describing a similar rearrangement found in tetramesityldigermene, a compound containing a germanium-germanium double bond. Finally, the thesis details initial investigations into the reactivity of the germasilene with various protic reagents and carbonyl compounds.;Throughout the thesis, emphasis is placed on rationalizing the reactivity of the germasilene with respect to similar compounds containing double bonds between the heavier group 14 elements. Comparisons to the theoretical predictions of the structure and reactivity of these compounds are included, and attempts are made to rationalize any differences between what is predicted theoretically and what is found experimentally

Promoting and supporting credibility in neuroscience

No abstract available

Promoting and supporting credibility in neuroscience.

No abstract available

Lifting the lid on impact and peer review.

Brain and Neuroscience Advances has grown in tandem with the British Neuroscience Association's campaign to build Credibility in Neuroscience, which encourages actions and initiatives aimed at improving reproducibility, reliability and openness. This commitment to credibility impacts not only what the Journal publishes, but also how it operates. With that in mind, the Editorial Board sought the views of the neuroscience community on the peer review process, and on how they should respond to the Journal Impact Factor that will be assigned to Brain and Neuroscience Advances. In this editorial, we present the results of a survey of neuroscience researchers conducted in the autumn of 2020 and discuss the broader implications of our findings for the Journal and the neuroscience community

Beyond the Baroreflex: A New Measure of Autonomic Regulation Based on the Time-Frequency Assessment of Variability, Phase Coherence and Couplings

For decades the role of autonomic regulation and the baroreflex in the generation of the respiratory sinus arrhythmia (RSA) - modulation of heart rate by the frequency of breathing - has been under dispute. We hypothesized that by using autonomic blockers we can reveal which oscillations and their interactions are suppressed, elucidating their involvement in RSA as well as in cardiovascular regulation more generally. R-R intervals, end tidal CO2, finger arterial pressure, and muscle sympathetic nerve activity (MSNA) were measured simultaneously in 7 subjects during saline, atropine and propranolol infusion. The measurements were repeated during spontaneous and fixed-frequency breathing, and apnea. The power spectra, phase coherence and couplings were calculated to characterise the variability and interactions within the cardiovascular system. Atropine reduced R-R interval variability (p \u3c 0.05) in all three breathing conditions, reduced MSNA power during apnea and removed much of the significant coherence and couplings. Propranolol had smaller effect on the power of oscillations and did not change the number of significant interactions. Most notably, atropine reduced R-R interval power in the 0.145–0.6 Hz interval during apnea, which supports the hypothesis that the RSA is modulated by a mechanism other than the baroreflex. Atropine also reduced or made negative the phase shift between the systolic and diastolic pressure, indicating the cessation of baroreflex-dependent blood pressure variability. This result suggests that coherent respiratory oscillations in the blood pressure can be used for the non-invasive assessment of autonomic regulation

Assessment and Management of Adult Preoperative Anxiety: A Survey of the Anesthesiologist Perspective

Introduction: Preoperative anxiety often goes unaccounted for in the surgical setting. Given that anesthesiologists are routinely involved in perioperative care, this study was performed to assess anesthesiologists’ views of adult preoperative anxiety assessment and management. Methods: Active members of the American Society of Anesthesiologists (ASA) were sent an online questionnaire. Survey items included demographic information in addition to questions about measurement of preoperative anxiety, management of anxiety, and which entities were allocated responsibility to reduce patient anxiety. Data were collected from February to March 2019. Results: Of 3,661 respondents, most asked their patients about preoperative anxiety (n=2332, 64.3%). The following techniques were supported to reduce preoperative anxiety: pharmacotherapy (n=3205, 91.6%), patient education (n=2493, 71.3%), preoperative anesthesiologist visit (n=2095, 59.9%), family members’ presence (n=1828, 52.3%), preoperative tours (n=660, 18.9%), nurse-patient empathetic interactions (n=622, 17.8%), traditional, complementary, or alternative medicine (n=243, 7.0%), other techniques (n=219, 6.3%), cognitive behavioral therapy (n=107, 3.1%), or referral to a psychologist/psychiatrist (n=44, 1.3%). Discussion: Most anesthesiologists formally assessed preoperative anxiety and indicated a willingness to discuss anxiety if raised by the patient. Most anesthesiologists preferred to administer anxiety medication to reduce preoperative anxiety, but several other techniques were supported

Iterative focused screening with biological fingerprints identifies selective Asc-1 inhibitors distinct from traditional high throughput screening

N-methyl-d-aspartate receptors (NMDARs) mediate glutamatergic signaling that is critical to cognitive processes in the central nervous system, and NMDAR hypofunction is thought to contribute to cognitive impairment observed in both schizophrenia and Alzheimer’s disease. One approach to enhance the function of NMDAR is to increase the concentration of an NMDAR coagonist, such as glycine or d-serine, in the synaptic cleft. Inhibition of alanine–serine–cysteine transporter-1 (Asc-1), the primary transporter of d-serine, is attractive because the transporter is localized to neurons in brain regions critical to cognitive function, including the hippocampus and cortical layers III and IV, and is colocalized with d-serine and NMDARs. To identify novel Asc-1 inhibitors, two different screening approaches were performed with whole-cell amino acid uptake in heterologous cells stably expressing human Asc-1: (1) a high-throughput screen (HTS) of 3 M compounds measuring 35S l-cysteine uptake into cells attached to scintillation proximity assay beads in a 1536 well format and (2) an iterative focused screen (IFS) of a 45 000 compound diversity set using a 3H d-serine uptake assay with a liquid scintillation plate reader in a 384 well format. Critically important for both screening approaches was the implementation of counter screens to remove nonspecific inhibitors of radioactive amino acid uptake. Furthermore, a 15 000 compound expansion step incorporating both on- and off-target data into chemical and biological fingerprint-based models for selection of additional hits enabled the identification of novel Asc-1-selective chemical matter from the IFS that was not identified in the full-collection HTS

Probing the extragalactic fast transient sky at minute timescales with DECam

Searches for optical transients are usually performed with a cadence of days to weeks, optimised for supernova discovery. The optical fast transient sky is still largely unexplored, with only a few surveys to date having placed meaningful constraints on the detection of extragalactic transients evolving at sub-hour timescales. Here, we present the results of deep searches for dim, minute-timescale extragalactic fast transients using the Dark Energy Camera, a core facility of our all-wavelength and all-messenger Deeper, Wider, Faster programme. We used continuous 20s exposures to systematically probe timescales down to 1.17 minutes at magnitude limits $g > 23$ (AB), detecting hundreds of transient and variable sources. Nine candidates passed our strict criteria on duration and non-stellarity, all of which could be classified as flare stars based on deep multi-band imaging. Searches for fast radio burst and gamma-ray counterparts during simultaneous multi-facility observations yielded no counterparts to the optical transients. Also, no long-term variability was detected with pre-imaging and follow-up observations using the SkyMapper optical telescope. We place upper limits for minute-timescale fast optical transient rates for a range of depths and timescales. Finally, we demonstrate that optical $g$-band light curve behaviour alone cannot discriminate between confirmed extragalactic fast transients such as prompt GRB flashes and Galactic stellar flares.Comment: Published in MNRA