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In-cage recombination facilitates the enantioselective organocatalytic [1,2]-rearrangement of allylic ammonium ylides
Get PDFFunding: The research leading to these results has received funding from Syngenta and the EPSRC Centre for Doctoral Training in Critical Resource Catalysis (W.C.H., CRITICAT, EP/L016419/1; K.K., EP/T023643/1; A.B.F., EP/J018139/1). A.D.S. and K.K. thank the EPSRC Programme Grant “Boron: Beyond the Reagent” (EP/W007517) for support. P.H.-Y.C. is the Bert and Emelyn Christensen Professor and gratefully acknowledges financial support from the Stone Family of OSU. Financial support from the National Science Foundation (NSF) (CHE-1352663) is acknowledged. T.F., H.B.W., J.M.L., and P.H.-Y.C. acknowledge computing infrastructure in part provided by the NSF Phase-2 CCI, Center for Sustainable Materials Chemistry (CHE-1102637).The [1,2]-rearrangement of allylic ammonium ylides is traditionally observed as a competitive minor pathway alongside the thermally allowed [2,3]-sigmatropic rearrangement. Concerted [1,2]-rearrangements are formally forbidden, with these processes believed to proceed through homolytic C–N bond fission of the ylide, followed by radical–radical recombination. The challenges associated with developing a catalytic enantioselective [1,2]-rearrangement of allylic ammonium ylides therefore lie in biasing the reaction pathway to favor the [1,2]-reaction product, alongside controlling a stereoselective radical–radical recombination event. Herein, a Lewis basic chiral isothiourea facilitates catalytic [1,2]-rearrangement of prochiral aryl ester ammonium salts to generate unnatural α-amino acid derivatives with up to complete selectivity over the [2,3]-rearrangement and with good to excellent enantiocontrol. Key factors in favoring the [1,2]-rearrangement include exploitation of disubstituted terminal allylic substituents, cyclic N-substituted ammonium salts, and elevated reaction temperatures. Mechanistic studies involving 13C-labeling and crossover reactions, combined with radical trapping experiments and observed changes in product enantioselectivity, are consistent with a radical solvent cage effect, with maximum product enantioselectivity observed through promotion of “in-cage” radical–radical recombination. Computational analysis indicates that the distribution between [1,2]- and [2,3]-rearrangement products arises predominantly from C–N bond homolysis of an intermediate ammonium ylide, followed by recombination of the α-amino radical at either the primary or tertiary site of an intermediate allylic radical. Electrostatic interactions involving the bromide counterion control the facial selectivity of the [1,2]- and [2,3]-rearrangements, while the sterically hindered tertiary position of the allylic substituent disfavors the formation of the [2,3]-product. These results will impact further investigations and understanding of enantioselective radical–radical reactions.Peer reviewe
Seroprevalence of Japanese encephalitis virus-specific antibodies in Australia following novel epidemic spread : protocol for a national cross-sectional study
Get PDFFunding: Australian governments fund Australian Red Cross Lifeblood to provide blood, blood products and services to the Australian community.Introduction Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that causes encephalitis and other morbidity in Southeast Asia. Since February 2022, geographically dispersed JEV human, animal and vector detections occurred on the Australian mainland for the first time. This study will determine the prevalence of JEV-specific antibodies in human blood with a focus on populations at high risk of JEV exposure and determine risk factors associated with JEV seropositivity by location, age, occupation and other factors. Method Samples are collected using two approaches: from routine blood donors (4153 samples), and active collections targeting high-risk populations (convenience sampling). Consent-based sampling for the latter includes a participant questionnaire on demographic, vaccination and exposure data. Samples are tested for JEV-specific total antibody using a defined epitope-blocking ELISA, and total antibody to Australian endemic flaviviruses Murray Valley encephalitis and Kunjin viruses. Analysis Two analytic approaches will occur: descriptive estimates of seroprevalence and multivariable logistic regression using Bayesian hierarchical models. Descriptive analyses will include unadjusted analysis of raw data with exclusions for JEV-endemic country of birth, travel to JEV-endemic countries, prior JEV-vaccination, and sex-standardised and age-standardised analyses. Multivariable logistic regression will determine which risk factors are associated with JEV seropositivity likely due to recent transmission within Australia and the relative contribution of each factor when accounting for effects within the model. Ethics National Mutual Acceptance ethical approval was obtained from the Sydney Children’s Hospitals Network Human Research Ethics Committee (HREC). Local approvals were planned to be sought in each jurisdiction, as per local ethics processes. Ethical approval was also obtained from the Australian Red Cross Lifeblood HREC. Dissemination Findings will be communicated to participants and their communities, and human and animal health stakeholders and policy-makers iteratively and after final analyses. Understanding human infection rates will inform procurement and targeted allocation of limited JEV vaccine, and public health strategies and communication campaigns, to at-risk populations.Peer reviewe
Modelling meaning : a logico-algebraic investigation of hyperintensionality
Get PDFThis dissertation studies and contributes to a recent trend of mathematical innovations linked to the hyperintensional revolution in formal semantics. It does so against the backdrop of a methodological pluralism that we defend in the first part of the thesis. We characterise semantics as a model-building activity and piggyback on a general pluralism about scientific models to motivate a metasemantics centered around the study of networks of distinct but complementary semantic models. The precise pluralism we endorse is two-tiered: two semantic models can bifurcate on the granularity at which meanings are modelled − the resolution each models targets − or on the techniques deployed in their respective formal apparatus − on the modelling style used to capture that target. This leads us to organise our metasemantics as a bi-dimensional cartography of semantic models.
We focuses on two-component semantics − which is based on the idea that propositions are characterised both by their truth-conditions and their subject-matter. The second part of dissertation lays out the basic semantic machinery of two-component semantics and and organises its multiple implementations in the context of our two-tier pluralism. In particular, we consider both the American and the Australian plans for paradefinite negation.
The third part explores various ontological modelling of truth-supporting circumstances and of aboutness-supporting topics as well as their semantic upshots. This exploration culminates in the result that particular implementations of two-component semantics lead to truthmaker semantics, a competing hyperintensional framework. This bridge between two-component and truthmaker semantics allows us to further our understanding of the preexisting American-style truthmaker semantics but also to develop an original Australianstyle truthmaker semantics."This work was supported by the Scottish Graduate School for Arts & Humanities [grant number AH/R012717]. This work was supported by the St Leonard’s College European Doctoral Stipend Scholarship."--Fundin
An account on functional polymer composite for multivariant application : a mechanistic approach
Get PDFThe presented article reports a detailed review of the polymer composite and its applications in multifaceted areas. The novelty of the report is in establishing the mechanistic overview on the functionalization of polymer for selective applications. The most important and established application of polymer is in sensing, polymer electrolyte, biomedical application, point of care application etc. The utilization of functional polymer in fluorescence thermometers is dependent on the maintenance of their lower critical solubility temperature. Polyelectrolytes like conducting polymers are widely applied for chemo sensing applications. The primary mechanism for the functionality of these conducting polymers is the presence of altering single and double bonds which enables the thorough flow of charge within the matrix system. Furthermore, the macromolecular synthetic polymer is subjected to functionalization through composite upon combing with specific salts and filler components. The addition of unreactive/reactive filler components in minute amounts is reported to significantly reduce the polarization loss and increase the cyclability of the matrix when applied to solid-state devices like sensors, fuel cells for stationary and mobile applications, etc. Fuels cells being an example of renewable energy is reported to attract the modern market with emphasis on polymer membrane-based system wherein sulphonic acid-based electrolyte membrane act as the ionic electrolyte conductor. The mechanism of ion conduction within the polymer matrix plays an important role in the application in solid-state devices like sensors, fuel cells, batteries, etc. The review briefly explains the role of ionic conduction as explained using two primary mechanisms like Arrhenius and Vogel Tammann Fulcher. Finally, the role of polymer bio composites is discussed in light of biomedical applications.Peer reviewe
Patients' emotional expressions and clinicians' responses in oncology – from recognition to exploration of concerns
Get PDFFunding: Fernanda Bittencourt Romeiro reports financial support was provided by Coordination for the Improvement of Higher Education Personnel – Brazil (CAPES) – Financing Code 001.Objectives: The objective of this study was to analyze patient's emotional expressions during the consultations and the responses of their oncologists to these expressions. Methods: The study employed a mixed-method, observational, descriptive, and explanatory design. A total of 31 adult patients at different clinical stages, undergoing cancer treatment and 8 oncologists were included. Thirty-one routine outpatient oncology consultations were analyzed, after being transcribed and coded, using the Portuguese version of the Verona Coding Definitions of Emotional Sequences (VR-CoDES). Results: The oncologists elicited and recognized patients' emotional concerns but they did not explore them in a way that encouraged patients to continue verbalizing their feelings. Oncologists provided more directive and guidance-oriented responses, focusing on cues related to physical pain and symptoms. Multilevel logistic regression analysis modeled the probability of oncologists' responses showing reduction of space in relation to patients' emotional cues/concerns, controlling for clustering and patients' clinical and socio-demographic variables. The type of cue and treatment influenced the oncologists' responses. Conclusions: Communication skills training focused on the ability to better explore patients' emotions may help oncologists to provide more explicit and empathetic responses that validate the emotional content expressed during consultations. Practice Implications: Oncologists do not use the same responses as a standard with patients, thus adjusting them individually.Peer reviewe
Turkish leaders and their foreign policy decision-making style : a comparative and multi-method perspective
Get PDFFunding: The authors gratefully acknowledge that this research was supported by a TUBITAK Evrena grant (110K112).Using both quantitative and qualitative research techniques, we investigate the effect of leaders’ style and personality on foreign policy. The study examines six Turkish leaders, Süleyman Demirel, Bülent Ecevit, Necmettin Erbakan, Recep Tayyip Erdoğan, Abdullah Gül, and Turgut Özal, and 18 foreign policy cases to answer the following questions: do Turkish leaders differ from each other in terms of their personality traits and styles?; how did their styles affect their foreign policy choices?; and how did they react to various domestic and international constraints they encountered in cases of foreign policy? Our findings suggest that: (a) in terms of their personality traits, Turkish leaders do not collectively fit in one category; (b) there are some stark differences among our six leaders, although some leaders are more similar to each other than others in terms of their personality traits and styles; (c) these differences were observable in the foreign policy decisions they made.Peer reviewe
Genome analysis of ESBL-producing Escherichia coli isolated from pigs
Get PDFFunding: L.L.F. Founou and R.C. Founou were funded by the Antimicrobial Research Unit (ARU) and College of Health Sciences (CHS) of the University of KwaZulu-Natal, South Africa. The National Research Foundation funded this study through the NRF Incentive Funding for Rated Researchers (Grant No. 85595), and the DST/NRF South African Research Chair in Antibiotic Resistance and One Health (Grant No. 98342) awarded to S.Y. Essack. The South African Medical Research Council also funded the study through the Self-Initiated Researcher (SIR) Grant awarded to S.Y Essack.The resistome, virulome and mobilome of extended spectrum ß-lactamase (ESBL)-producing Escherichia coli (ESBL-Ec) isolated from pigs in Cameroon and South Africa were assessed using whole genome sequencing (WGS). Eleven clonally related phenotypic ESBL-Ec isolates were subjected to WGS. The prediction of antibiotic resistance genes, virulence factors (VFs) and plasmids was performed using ResFinder, VirulenceFinder and PlasmidFinder, respectively. Diverse sequence types (STs) were detected with ST2144 and ST88 being predominant and blaCTX-M-15 (55%) being the principal ESBL gene. All except two isolates harboured various aminoglycoside resistance genes, including aph(3″)-Ib (6/11, 55%) and aph(6)-1d (6/11, 55%), while the qnrS1 gene was identified in four of the isolates. The ESBL-Ec isolates showed a 93.6% score of being human pathogens. The fim, ehaB, ibeB/C were the leading virulence factors detected. All isolates harboured at least three extraintestinal pathogenic E. coli (ExPEC) VFs, with one isolate harbouring up to 18 ExPEC VFs. Five isolates (45.45%) harboured the plasmid incompatibility group IncF (FII, FIB, FIC, FIA). The study revealed that there is an urgent need to implement effective strategies to contain the dissemination of resistant and virulent ESBL-Ec through the food chain in Cameroon and South Africa.Peer reviewe
‘A marriage of convenience’ : inter-organizational learning through strategic collaboration
Get PDFCollaboration is often used to combine capabilities and share resources to deliver strategic goals. The process has potential to support organizational learning and intertwining of knowledge between participating organizations. However, this often overlooks the complexities and contexts that make collaborations prone to failure. This paper explores inter-organizational learning between two police forces in the United Kingdom as they embark on a strategic partnership through collaboration. We investigate how learning emerges through the collaboration, what tensions surface as the partnership develops and how these tensions are resolved. Our research contributes to inter-organizational learning theory in three ways. Firstly, we show that inter-organizational learning is a multi-level process through practices that occur at inter-personal, inter-group and inter-organizational levels. Secondly, we highlight that key tensions attenuate the effectiveness of learning processes. Finally, we note that the outcomes of institutionalized learning — that is, merging infrastructure, standardizing processes and creating a shared identity — are interconnected, and that inter-organizational learning cannot be achieved without all three being embedded successfully. We offer new and important insights into the collaborative learning efforts that promote strategic partnership and integration.Peer reviewe
Foundation stone of empire : the role of Portland stone in ‘heritage’, commemoration, and identity
Get PDFIn 2013, Portland Stone, a creamy white limestone from the Isle of Portland in Dorset, was named the world’s first “Global Heritage Stone Resource” (GSHR) by the Heritage Stone Task Group, a sub-commission of the International Union of Geological Sciences. The criteria for GSHR designation are ambiguous, with the Task Group championing Portland Stone’s “cultural value” and “heritage,” neither of which are critically interrogated. In this paper we undertake a detailed critical discourse analysis of Hansard entries mentioning Portland Stone between 1803 and 2020. We reveal that the use of Portland Stone is intertwined with colonial oppression, class subjugation, empire politics, structural racism, and a mythologised, England-centric vision of British national identity. In celebrating the use of Portland Stone as part of Britain’s “heritage”, we are condoning a narrative of Britishness that is exclusionary and whitewashed, and that supports an elite rewriting of national and international history. Drawing on critical heritage literature, we argue that the Heritage Stone Task Group must urgently reconsider their uncritical appraisal of “heritage” and “culture” and consult with social science colleagues to ensure that all voices are heard. Our study shows that through the history and nature of their usage, the rocks beneath our feet, our natural foundation, can become imbued with notions of regional and national identity, belonging and exclusion, memory and loss – they can become a powerful manifestation of symbolic and unequal power structures. While British society’s attention is turned to the imprint of colonialism, empire, and race on our geographies, we urge further consideration of the built environment: the very stones that construct our towns and cities, the plinths on which statues are erected, tell stories of oppression and domination that are an important part of British history, culture, and heritage.Peer reviewe
Covid-19, board of directors and pessimism in annual reports : an intention to mitigate litigation risk
Get PDFThis study examines the impact of corporate COVID-19 disclosure on the negative tone (pessimism) in annual reports. We also investigate how board size and board independence influence pessimism in annual reports. Using a U.K. sample from 2020, we employ various techniques to explore the COVID-19 disclosure-pessimism nexus. Our findings, supported by Tobit regression and a two-stage least squares (2SLS) model, reveal a positive association between COVID-19 disclosure and pessimism in annual reports. We observe that managers tend to disclose COVID-19 information pessimistically as a risk mitigation strategy, aiming to prevent future earning shocks and potential litigation costs. Interestingly, our results also indicate that large boards and independent directors can bolster governance power, safeguarding firms against potential litigation costs by increasing pessimism in annual reports, both during and beyond the COVID-19 pandemic.Peer reviewe
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