1,149 research outputs found
Visualization of studentsâ cognitive knowledge in digital concept mapping
Meaningful learning through the creation a digital concept map is the easiest way to gain cognitive knowledge, new information, and possibility how to expand among learners. Only a few empirical studies have been conducted in the field of nursing regarding learning through concept mapping to achieve higher levels of knowledge and digital skills. The study evaluated the studentâs ability to visualize cognitive knowledge by creating a digital concept map. The objectives were to identify the perception using digital technologies and conceptual mapping, differences and relationships between gender, age, years of study, and branches. We used the ContextMinds program map creation. There were 92 Slovak students of nursing, public health and physiotherapy participated in the study. Data were collected and analyzed using IBM SPSS version 25.0. Perception of learning using digital concept mapping strategy was assessed using descriptive statistics, where paired t-test, analysis of variance (ANOVA) and Chi-square were used. The study found a positive perception of creating the digital concept map, but a low level of digital skills. First-year students took one or more weeks to submit the final version of the concept map in comparison to third-year students who took one or more hours. For second-year students, a creation of a concept map was less problematic than for first-year students. Students prefer standard teaching and learning methods. Healthcare absolvents are required to be proficient in digital literacy. Applying cognitive knowledge to create a digital concept map is a challenging strategy procedure
Novel applications of triarylfluoroboranes in organic synthesis
The work described in this thesis is concerned with the utilisation of bulky boron-based Lewis
acids as catalysts in organic synthesis. Chapter one provides a general introduction towards the
bulky boron-based Lewis acids and diazo compounds, wherein their general synthesis,
reactivity, and utilisation in the organic synthesis will be discussed in more detail. Furthermore,
the introductory part of this thesis will cover frustrated Lewis pairs, including how they can
activate small molecules via two different pathways and how such divergent activation was
later utilised in the organic synthesis. Chapter two and three will cover the use of
tris(pentafluorophenyl)borane as a catalyst for alkenylation and cyclopropenation of diazo
esters, wherein the optimisation reactions, substrate scope, and reaction mechanism will be
discussed. Lastly, frustrated Lewis pairs mediated cross-coupling reactions of arylacetylenes
and aryl esters will be covered together with conducted studies for a determination of the
reaction mechanism
Real-time Graph Building on FPGAs for Machine Learning Trigger Applications in Particle Physics
We present a design methodology that enables the semi-automatic generation of
a hardware-accelerated graph building architectures for locally constrained
graphs based on formally described detector definitions. In addition, we define
a similarity measure in order to compare our locally constrained graph building
approaches with commonly used k-nearest neighbour building approaches. To
demonstrate the feasibility of our solution for particle physics applications,
we implemented a real-time graph building approach in a case study for the
Belle~II central drift chamber using Field-Programmable Gate Arrays~(FPGAs).
Our presented solution adheres to all throughput and latency constraints
currently present in the hardware-based trigger of the Belle~II experiment. We
achieve constant time complexity at the expense of linear space complexity and
thus prove that our automated methodology generates online graph building
designs suitable for a wide range of particle physics applications. By enabling
an hardware-accelerated pre-processing of graphs, we enable the deployment of
novel Graph Neural Networks~(GNNs) in first level triggers of particle physics
experiments.Comment: 18 page
Radical Reactivity of Frustrated Lewis Pairs with Diaryl Esters
Advances in the chemistry of metal-free systems known as frustrated Lewis pairs (FLPs) has exposed new reactivity of the p-block elements, particularly in small-molecule activation and catalysis. Typically, the mode of activation by FLPs has been predicated on a heterolytic two-electron process, although recently, select FLPs have been shown to participate in single-electron processes. Here, we report the reaction of diaryl substituted esters with FLPs. This results in divergent pathways, one whereby the diaryl moiety is stabilized by the Lewis basic phosphine, and the alternative pathway, wherein a single-electron transfer process occurs, generating the [Mes_{3}P]+â
/[C(H)Ar_{2}]â
radical ion pair. The latter species undergoes a homocoupling reaction to yield tetraphenylethane derivatives. In the presence of olefins, this reactivity can be harnessed through an sp^{2}-sp^{3} CâC heterocoupling reaction to generate α,ÎČ-substituted olefins. Notably, this work showcases an FLP approach to metal-free radical CâH bond activation with subsequent CâC bond formation, which also displays complementary reactivity to other approaches
Borane catalysed cyclopropenation of arylacetylenes
Triarylboranes have gained substantial attention as catalysts for CâC bond forming reactions due to their remarkable catalytic activities. Herein, we report B(C6F5)3 catalysed cyclopropenation of a wide variety of arylacetylenes using donorâacceptor diazoesters. A mild reaction protocol has been developed for the synthesis of functionalised cyclopropenes (33 examples) in good to excellent yields
Tumour-derived alkaline phosphatase regulates tumour growth, epithelial plasticity and disease-free survival in metastatic prostate cancer
BACKGROUND: Recent evidence suggests that bone-related parameters are the main prognostic factors for overall survival in advanced prostate cancer (PCa), with elevated circulating levels of alkaline phosphatase (ALP) thought to reflect the dysregulated bone formation accompanying distant metastases. We have identified that PCa cells express ALPL, the gene that encodes for tissue nonspecific ALP, and hypothesised that tumour-derived ALPL may contribute to disease progression. METHODS: Functional effects of ALPL inhibition were investigated in metastatic PCa cell lines. ALPL gene expression was analysed from published PCa data sets, and correlated with disease-free survival and metastasis. RESULTS: ALPL expression was increased in PCa cells from metastatic sites. A reduction in tumour-derived ALPL expression or ALP activity increased cell death, mesenchymal-to-epithelial transition and reduced migration. Alkaline phosphatase activity was decreased by the EMT repressor Snail. In men with PCa, tumour-derived ALPL correlated with EMT markers, and high ALPL expression was associated with a significant reduction in disease-free survival. CONCLUSIONS: Our studies reveal the function of tumour-derived ALPL in regulating cell death and epithelial plasticity, and demonstrate a strong association between ALPL expression in PCa cells and metastasis or disease-free survival, thus identifying tumour-derived ALPL as a major contributor to the pathogenesis of PCa progression.British Journal of Cancer advance online publication, 22 December 2016; doi:10.1038/bjc.2016.402 www.bjcancer.com
Site-selective Csp3âCsp/Csp3âCsp2 cross-coupling reactions using frustrated Lewis pairs
The donorâacceptor ability of frustrated Lewis pairs (FLPs) has led to widespread applications in organic synthesis. Single electron transfer from a donor Lewis base to an acceptor Lewis acid can generate a frustrated radical pair (FRP) depending on the substrate and energy required (thermal or photochemical) to promote an FLP into an FRP system. Herein, we report the Csp3âCsp cross-coupling reaction of aryl esters with terminal alkynes using the B(C6F5)3/Mes3P FLP. Significantly, when the 1-ethynyl-4-vinylbenzene substrate was employed, the exclusive formation of Csp3âCsp cross-coupled products was observed. However, when 1-ethynyl-2-vinylbenzene was employed, solvent-dependent site-selective Csp3âCsp or Csp3âCsp2 cross-coupling resulted. The nature of these reaction pathways and their selectivity has been investigated by extensive electron paramagnetic resonance (EPR) studies, kinetic studies, and density functional theory (DFT) calculations both to elucidate the mechanism of these coupling reactions and to explain the solvent-dependent site selectivity
Triarylborane-catalysed alkenylation reaction of aryl esters with diazo compounds
Herein we report a facile, mild reaction protocol to form carbonâcarbon bonds in the absence of transition metal catalysts. We demonstrate the metalâfree alkenylation reactions of aryl esters with αâdiazoesters to give highly functionalized enyne products. Catalytic amounts of tris(pentafluorophenyl)borane (10â20 mol%) are employed to afford the C=C coupled products (31 examples) in good to excellent yields (36â87%). DFT studies have been undertaken to elucidate the mechanism for this alkenylation reaction
Tris(pentafluorphenyl)boran-katalysierte Erzeugung von Carbenium-Ionen und autokatalytische Pyrazol-Synthese â eine theoretische und experimentelle Studie
In den letzten Jahren hat sich die metallfreie organische Synthese unter Verwendung von Triarylboranen als Katalysatoren zu einem weit verbreiteten Forschungsgebiet entwickelt. Hier berichten wir ĂŒber eine umfassende theoretische und experimentelle Studie fĂŒr die hochselektive Synthese von N-substituierten Pyrazolen durch die Erzeugung von Carbenium-Ionen aus der Reaktion zwischen Arylestern und Vinyldiazoacetaten in Gegenwart von katalytischem Tris(pentafluorphenyl)boran [B(C6F5)3]. DFT-Studien zum Reaktionsmechanismus zeigen, dass die In-situ-Generierung einer Carbenium-Spezies als Autokatalysator fungiert, welcher die regiospezifische Bildung von N-substituierten Pyrazolen in guter bis hervorragender Ausbeute (bis zu 81â%) auslöst
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