One key challenge in the field of exploitation of solar energy is to store the energy and make it available on demand. One possibility is to use photochromic molecules that undergo light‐induced ...isomerization to metastable isomers. Here we present efforts to develop solar thermal energy storage systems based on the dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch. New DHA derivatives with one electron‐withdrawing cyano group at position 1 and one or two phenyl substituents in the five‐membered ring were prepared by using different synthetic routes. In particular, a diastereoselective reductive removal of one cyano group from DHAs incorporating two cyano groups at position 1 turned out to be most effective. Quantum chemical calculations reveal that the structural modifications provide two benefits relative to DHAs with two cyano groups at position 1: 1) The DHA–VHF energy difference is increased (i.e., higher energy capacity of metastable VHF isomer); 2) the Gibbs free energy of activation is increased for the energy‐releasing VHF to DHA back‐reaction. In fact, experimentally, these new derivatives were so reluctant to undergo the back‐reaction at room temperature that they practically behaved as DHA to VHF one‐way switches. Although lifetimes of years are at first attractive, which offers the ultimate control of energy release, for a real device it must of course be possible to trigger the back‐reaction, which calls for further iterations in the future.
Molecular solar thermal energy storage: Derivatives of the dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch with only one cyano group at position 1 were prepared and investigated experimentally and theoretically. Compared to derivatives with two cyano groups, these compounds exhibit larger energy differences between DHA and VHF isomers and hence larger energy storage capacities, while the VHF to DHA back‐reaction is on hold (see scheme).
Abstract Background Over the past decade, ultrasound utilization has increased within anesthesia and intensive care medicine, enhancing patient safety and diagnostic accuracy. However, the frequency ...of ultrasound usage and operator training in the Nordic countries remain unclear. This project aims to perform a survey on ultrasound availability, daily clinical use, and how ultrasound skills are trained and assessed, among anesthesiologists. Methods This online cross‐sectional survey will include anesthesiologists from the Nordic countries. The survey will adhere to the CROSS checklist. Survey items will be developed based on a formative model with a conceptual model, consisting of three main parts, including demographics, ultrasound machines and use, and skills development and assessment. The clinical relevance of items will be secured by including anesthesiologists of various levels of experience in the development of the survey. Furthermore, experienced researchers in medical education will participate in the development, contributing with relevant medical educational perspectives. Data will be summarized using a non‐parametric descriptive approach. A chi‐squared test will examine relevant relationships between certain answers. Results Results will be published in a peer‐reviewed journal and presented at relevant scientific conferences and meetings. Conclusion This study may find a high availability of ultrasound machines and frequent use in the clinical departments. Despite this expected daily use of ultrasound, missing standardized structured skills acquisition and assessment could be uncovered. The results of this study may contribute to mapping various aspects of clinical ultrasound and skills development for further use in research.
Abstract Background Access to the neuraxial space, including lumbar punctures and neuraxial anaesthesia, is an everyday procedure in clinical practice. Traditionally these procedures rely on manual ...palpation technique, but ultrasound is a useful tool when patients prove challenging. Presently, there is a lack of evidence‐based guidelines for technical skills acquisition, both with and without ultrasound, and likewise, competency assessment approaches vary globally. Accordingly, we aim to assess the current evidence regarding learning and assessment in neuraxial access ultrasound, for future educational recommendations. Methods This scoping review will be conducted in accordance with the Preferred Reporting Items for Systematic and Meta‐Analysis (PRISMA) statement, together with the PRISMA Extension for Scoping Reviews. A systematic search strategy will be based on a PICO approach, focusing on physicians, medical students, or nurses being exposed to education, training, or assessment in procedural neuraxial access ultrasound. No comparators are obligated, but outcomes should be assessable using the Kirkpatrick four levels of training evaluation. The search will be performed in Cochrane Library, Embase, Medline, Scopus, PubMed, and CINAHL. Independently, two authors will screen the studies and conflicts will be resolved by a third author. Relevant predefined data will be extracted and analysed using a descriptive approach. The quality of the studies will be assessed using the Medical Education Research Study Quality Instrument. Discussion This scoping review will contribute by presenting gathered evidence of an overview of the different approaches to achieving education and training of technical skills in neuraxial access, and how skills are tested, which could guide research and future recommendations for skills development and assessment.
The conversion and efficient storage of solar energy is recognized to hold significant potential with regard to future energy solutions. Molecular solar thermal batteries based on photochromic ...systems exemplify one possible technology able to harness and apply this potential. Herein is described the synthesis of a macrocycle based on a dimer of the dihydroazulene/vinylheptafulvene (DHA/VHF) photo/thermal couple. By taking advantage of conformational strain, this DHA–DHA macrocycle presents an improved ability to absorb and store incident light energy in chemical bonds (VHF–VHF). A stepwise energy release over two sequential ring‐closing reactions (VHF→DHA) combines the advantages of an initially fast discharge, hypothetically addressing immediate energy consumption needs, followed by a slow process for consistent, long‐term use. This exemplifies another step forward in the molecular engineering and design of functional organic materials towards solar thermal energy storage and release.
What goes around comes around: Stepwise photoisomerizations are observed in a macrocycle incorporating two photochromic dihydroazulene units, resulting in two vinylheptafulvene units that thermally revert in a stepwise manner to the original dihydroazulene macrocycle, on a fast and slow timescale (see figure). The harnessed energy is thereby released on timescales for immediate and long‐term consumption needs in the context of molecular solar thermal batteries.
Water is one of the most reactive and abundant molecules on Earth, and it is thus crucial to understand its reactivity with various material families. One of the big unknown questions is how water in ...liquid and vapor forms impact the fast-emerging class of metal–organic frameworks (MOFs). Here, we discover that high-pressure water vapor drastically modifies the structure and hence the dynamic, thermodynamic, and mechanical properties of MOF glasses. In detail, we find that an archetypical MOF (ZIF-62) is extremely sensitive to heat treatments performed at 460 °C and water vapor pressures up to ∼110 bar. Both the melting and glass transition temperatures decrease remarkably (by >100 °C), and simultaneously, hardness and Young’s modulus increase by up to 100% under very mild treatment conditions (<20 bar of hydrothermal pressure). Structural analyses suggest water to partially coordinate to Zn in the form of a hydroxide ion by replacing a bridging imidazolate-based linker. The work provides insight into the role of hot-compressed water in influencing the structure and properties of MOF glasses and opens a new route for systematically changing the thermodynamics and kinetics of MOF liquids and thus altering the thermal and mechanical properties of the resulting MOF glasses.
Molecules comprised of three covalently linked bi‐stable switches can exist in states described by a combination of binary numbers, one for each individual switch: ⟨000⟩, ⟨001⟩, etc. Here we have ...linked three photo‐/thermoswitches together in a rigid macrocyclic structure, one azobenzene (bit no 1) and two dihydroazulenes (DHAs; bits no 2 and 3) and demonstrate how electronic interactions and unfavorable strain in some states can be used to control the speed by which a certain state is reached. More specifically, upon irradiation of state ⟨000⟩, the AZB isomerizes from trans to cis and the two DHAs to vinylheptafulvenes (VHFs), generating ⟨111⟩. The thermal VHF‐to‐DHA back‐reactions from this state also occur stepwise and can be accelerated by photo‐induced AZB cis‐to‐trans conversion, proceeding via ⟨011⟩ to ultimately furnish ⟨000⟩. Overall, the accessibility to a specific state of one bit was found to depend on the states of its neighboring bits.
Switching switching: Three photochromic units (two dihydroazulenes/vinylheptafulvenes, blue/red, and one azobenzene, green/orange) influence each other's photo/thermal switching behavior when incorporated in a macrocyclic structure. This means that accessibility to one specific state described by a combination of three binary numbers depends on the pathway to this state.
The discovery that the Ten-Eleven Translocation (TET) hydroxylases cause DNA demethylation has fundamentally changed the notion of how DNA methylation is regulated. Clonal analysis of the ...hematopoetic stem cell compartment suggests that TET2 mutations can be early events in hematologic cancers and recent investigations have shown TET2 mutations in diffuse large B-cell lymphoma. However, the detection rates and the types of TET2 mutations vary, and the relation to global methylation patterns has not been investigated. Here, we show TET2 mutations in 12 of 100 diffuse large B-cell lymphomas with 7% carrying loss-of-function and 5% carrying missense mutations. Genome-wide methylation profiling using 450K Illumina arrays identified 315 differentially methylated genes between TET2 mutated and TET2 wild-type cases. TET2 mutations are primarily associated with hypermethylation within CpG islands (70%; P<0.0001), and at CpG-rich promoters (60%; P<0.0001) of genes involved in hematopoietic differentiation and cellular development. Hypermethylated loci in TET2 mutated samples overlap with the bivalent (H3K27me3/H3K4me3) silencing mark in human embryonic stem cells (P=1.5×10(-30)). Surprisingly, gene expression profiling showed that only 11% of the hypermethylated genes were down-regulated, among which there were several genes previously suggested to be tumor suppressors. A meta-analysis suggested that the 35 hypermethylated and down-regulated genes are associated with the activated B-cell-like type of diffuse large B-cell lymphoma in other studies. In conclusion, our data suggest that TET2 mutations may cause aberrant methylation mainly of genes involved in hematopoietic development, which are silenced but poised for activation in human embryonic stem cells.
In the Difficult Airway Society's 2015 "cannot intubate, cannot oxygenate" guideline, the emergency cricothyroidotomy is the final option when managing an unanticipated difficult airway. How often ...training for maintenance of this skill is required for anesthesiologists remains unknown. We aimed to assess if specialist-trained anesthesiologists' skills improved from a brush-up intervention and if skills were retained after 3 months.
In this multicenter, randomized, controlled trial, participants were randomized to either a simulation-based brush-up or no brush-up. Both groups performed a mannequin-based technical skills emergency cricothyroidotomy test twice and were assessed by a blinded rater using a structured assessment tool that included time, positioning, palpation, appropriate employment of instruments, and stepwise progression. After 3 months of non-training, participants completed identical tests of retention.
A total of 54 anesthesiologists were included from three hospitals in the Region of Southern Denmark. Thirty-seven percent of the participants had received skills training in emergency cricothyroidotomy in the prior 12 months. The intervention group (N = 27) performed better in the initial tests, with a mean time of 51.5 s (SD = 10.82), a total score per minute of 15.9 points (SD = 4.91), and 93% passing both initial tests compared to the control group (N = 27) with a mean time of 76.8 s (SD = 35.82), a total score per minute of 6.6 (SD = 4.68) and only 15% passing both initial tests. The intervention group managed to retain overall performance in retention tests in terms of performance time (48.9 s, p = .26), total score per minute (13.6 points, p = .094), and passing the tests (75%, p = .059).
Exposure to simulation-based brush-up training in emergency cricothyroidotomy improved anesthesiologists' technical performance and was overall retained after 3 months. Some loss of skill concerning specific items was observed, highlighting the need for regular training in emergency cricothyroidotomy. Simulation-based training should be prioritized to improve and maintain technical skills in infrequent high-stakes procedures.
Focused lung ultrasound (FLUS) has high diagnostic accuracy in many common conditions seen in a variety of emergency settings. Competencies are essential for diagnostic success and patient safety but ...can be challenging to acquire in clinical environments. Immersive virtual reality (IVR) offers an interactive risk-free learning environment and is progressing as an educational tool. First, this study explored the educational impact of novice FLUS users participating in a gamified or non-gamified IVR training module in FLUS by comparing test scores using a test with proven validity evidence. Second, the learning effect was assessed by comparing scores of each group with known test scores of novices, intermediates and experienced users in FLUS. A total of 48 participants were included: 24 received gamified and 24 received non-gamified IVR training. No significant difference was found between gamified (mean = 15.5 points) and non-gamified (mean = 15.2 points), indicating that chosen gamification elements for our setup did not affect learning outcome (p = 0.66). The mean scores of both groups did not significantly differ from those of known intermediate users in FLUS (gamified p = 0.63, non-gamified p = 0.24), indicating that both IVR modules could be used as unsupervised out-of-hospital training for novice trainees in FLUS.
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