Gustavus Adolphus College Collections
Not a member yet
92910 research outputs found
Sort by
Development of three Higher Education professional learning networks in response to COVID-19: a case study
No full textThe COVID-19 (SARS-CoV-2) pandemic brought in-person teaching to an abrupt halt in March 2020 posing the problem of how to continue to deliver undergraduate courses remotely. This paper presents a detailed case study of three international online Higher Education (HE) teaching networks, formed to address the critical need to support laboratory teaching in the UK and Australia. The study employed a sequential mixed methods design using an online survey followed by structured discussions with network leads. The findings show these networks provided a space that was previously missing for knowledge development, building confidence, supporting collaboration, and reduced isolation of members. COVID-19 created a common purpose triggering the formation of these communities, but multiple factors contributed to their continued success: individuals prioritised engagement; both participants and their contributions were welcomed, and they subsequently felt able to lead change. The research found that the three networks fit the framework for Professional Learning Networks (PLN) providing a useful template for Higher Education PLNs operating anywhere in the world
Melatonin versus midazolam in the premedication of anxious children attending for elective surgery under general anaesthesia: the MAGIC non-inferiority RCT
No full textBackground
Anxiety in children prior to general anaesthesia is common, with up to half displaying distress. Anxiety and distress may lead to unsuccessful anaesthesia, together with greater postoperative pain, agitation and behavioural changes after surgery including sleep disturbances. Midazolam is the current standard premedication; however, it has adverse effects such as the potential for respiratory suppression and unpredictable effects which may result in agitation rather than anxiolysis. Melatonin is an alternative preoperative anxiolytic; however, previous trials have delivered conflicting results. The aim of this non-inferiority trial was to evaluate the effectiveness of melatonin compared to midazolam in reducing anxiety in children undergoing general anaesthesia.
Methods
We undertook a randomised-controlled, parallel-group, double-blind, non-inferiority trial in 20 United Kingdom National Health Service trusts, with an embedded qualitative study and health economic evaluation. Anxious children having day case elective surgery under general anaesthesia were randomly assigned to either control (standard of care) group: midazolam; or intervention group: melatonin. The primary outcome was preoperative distress (non-inferiority hypothesis) as assessed by modified Yale Preoperative Anxiety Scale Short Form. Secondary outcomes included safety and efficacy objectives. Analyses were by intention to treat, with an additional per-protocol analysis. The sample size of the trial was 624 children.
Results
The trial was stopped early due to recruitment futility. Between 30 July 2019 and 9 November 2022, 110 children were recruited; 55 allocated to midazolam and 55 allocated to melatonin. Pre-planned analyses showed an adjusted mean difference of 13.1 (95% confidence interval 3.7 to 22.4) for the intention-to-treat population and 12.9 (95% confidence interval 3.1 to 22.6) for the per-protocol population, in favour of midazolam. In both analyses, the upper limit of the 95% confidence interval exceeds the predefined margin of 4.3; therefore, melatonin is not non-inferior to midazolam. The lower limit of the 95% confidence intervals excludes zero and thus melatonin is inferior to midazolam; the difference found is considered to be clinically meaningful. Adverse events in the midazolam arm (26%) were slightly higher than melatonin (18%); there were no serious adverse events in either arm. Challenges to recruitment included study-related factors (eligibility criteria and trial design), participant factors (caregiver stress on the day of treatment) and practitioner factors (valuing predictability). In terms of acceptability, preferences of the anaesthetist, patient and caregiver factors and medication side effects profile were influential and suggest the choice of preoperative anxiolytic is more complex than previously described.
On average, costs over the 14 days post surgery were lower for those who received melatonin (−£46.20, 95% confidence interval −£166.14 to £66.74) with a mean incremental difference in procedure success of −0.02 (95% confidence interval −0.08 to 0.004), although there was uncertainty around the results.
Conclusion
In children with preoperative anxiety, midazolam is more effective than melatonin at reducing preoperative anxiety prior to general anaesthesia, although the early termination of the trial increases the likelihood of bias.
Limitations
The trial was prematurely terminated due to recruitment futility. Despite this, a clinically meaningful and statistically significant finding was observed about the primary outcome.
Future work
There remains a need to develop or repurpose another drug with a more favourable side effects profile to midazolam.
Funding
This synopsis presents independent research funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme as award number 16/80/08
Revision Rates for Aseptic Loosening in the Obese Patient: A Comparison Between Stemmed, Uncemented, and Unstemmed Tibial Total Knee Arthroplasty Components
No full textBackground
Total knee arthroplasty (TKA) is an effective treatment option for high body mass index (BMI) patients achieving similar outcomes to nonobese patients. However, increased rates of aseptic loosening in patients with a high BMI have been reported. Component fixation is a concern when performing TKA in the obese patient. To address this concern in cemented TKA, extended tibial stems have been used. Uncemented implants that take advantage of biologic osseointegration have also been advocated. This retrospective study examined the use of and revision rates of extended cemented tibial stems and uncemented implants compared with conventional cemented implants in our high BMI patient population.
Methods
We retrospectively reviewed a prospectively maintained database of 3239 primary Attune TKAs (Depuy, Warsaw, Indiana). All obese patients (BMI > 30 kg/m2) with > 30 months of follow-up were included in our analysis. Those who underwent cemented TKA using a tibial stem extension (Group 1) (n = 145) and those where cementless implants were used (Group 2) (n = 100) were compared to a control group (n = 1243) using a standard cemented implant. Primary outcome measures were all-cause revision, revision for aseptic loosening, and revision for tibial loosening. Kaplan-Meier survival analysis and Cox regression models were used to compare the primary outcomes between groups.
Results
In total, there were 1512 knees that met the inclusion criteria. The mean follow-up was 6.8, 5.1, and 5.3 years for cemented, stemmed, and cementless groups, respectively. There were 37 all-cause revisions identified. Seven were for aseptic loosening (2 tibial, 1 femoral, and 4 involving both components); all of these were in the standard cemented implant group. There were no revisions in the stemmed or cementless implant groups. Survival analysis did not show any significant differences between groups for either all-cause revision or for aseptic loosening.
Conclusions
This retrospective analysis showed that there were no revisions required for aseptic loosening when a cemented, stemmed, or uncemented implant was used in obese patients. These findings show that cementless and extended stem implants are a reasonable option in obese patients
Search for cascade decays of charged sleptons and sneutrinos in final states with three leptons and missing transverse momentum in pp collisions at √s =13 TeV with the ATLAS detector
No full textA search for cascade decays of charged sleptons and sneutrinos using final states characterized by three leptons (electrons or muons) and missing transverse momentum is presented. The analysis is based on a dataset with 140 fb−1 of proton-proton (pp) collisions at a center-of-mass energy of √s =13 TeV recorded by the ATLAS detector at the Large Hadron Collider. This paper focuses on a supersymmetric scenario that is motivated by the muon anomalous magnetic moment observation, dark-mattter relic density abundance, and electroweak naturalness. A mass spectrum involving light Higgsinos and heavier sleptons with a bino at intermediate mass is targeted. No significant deviation from the Standard Model expectation is observed. This search enables us to place stringent constraints on this model, excluding at the 95% confidence level charged slepton and sneutrino masses up to 450 GeV when assuming a lightest neutralino mass of 100 GeV and mass-degenerate selectrons, smuons and sneutrinos
Enhancing autophagy by redox regulation extends lifespan in Drosophila
No full textDysregulation of redox homeostasis is implicated in the ageing process and the pathology of age-related diseases. To study redox signalling by H2O2 in vivo, we established a redox-shifted model by manipulating levels of the H2O2-degrading enzyme catalase in Drosophila. Here we report that ubiquitous over-expression of catalase robustly extends lifespan in females. As anticipated, these flies are strongly resistant to a range of oxidative stress challenges, but interestingly are sensitive to starvation, which could not be explained by differences in levels of energy reserves. This led us to explore the contribution of autophagy, which is an important mechanism for organismal survival in response to starvation. We show that autophagy is essential for the increased lifespan by catalase upregulation, as the survival benefits are completely abolished upon global autophagy knock-down. Furthermore, using a specific redox-inactive knock-in mutant, we highlight the in vivo role of a key regulatory cysteine residue in Atg4a, which is required for the lifespan extension in our catalase model. Altogether, these findings confirm the redox regulation of autophagy in vivo as an important modulator of longevity
Experimental and Theoretical Study of the Kinetics of Dimerization of Ammonia at Low Temperatures
No full textThe kinetics of the dimerization of NH3 in helium and nitrogen bath gas within the supersonic flow of a Laval nozzle were investigated at very low temperatures. Experimentally, the fraction of the NH3 monomer, fmonomer, remaining in the flow at 91 K in N2 and at 35 K in He for a total bath gas density [M]∼5 × 1016 molecules cm-3 was monitored using fluorescence from the electronically excited NH2 photofragment formed following NH3 photolysis at 213 nm. No dimerization was observed up to [NH3] = 1 × 1015 molecules cm-3 for 160 mm downstream of the 91 K N2 nozzle, nor up to [NH3] = 5 × 1014 molecules cm-3 for 150 mm downstream of the 35 K He nozzle. Dimerization was observed at higher [NH3], being more pronounced at lower temperatures. For the Cs and C2h conformers of the NH3 dimer, calculations at the CCSD(T)/aug-cc-pVTZ level gave a zero-point vibrational-energy corrected binding energy of −7.52 and −7.33 kJ mol-1, respectively. Energy-grained master equation calculations based on statistical rate theory using the open-source MESMER package were used to calculate rate coefficients for dimerization, kdimer, over the temperature range T = 25-300 K and [M] = 1013-1022 molecules cm-3 for He and N2. kdimer displayed a negative T dependence and a positive [M] dependence and was found to be sensitive to changes in the low-lying vibrational frequencies of the NH3 dimer, for example, the inclusion of a hindered rotor potential for the internal twisting mode, which alters the density of states. Using the axial profiles of T, [M], and velocity for the Laval nozzles, the calculated values of kdimer were used to calculate fmonomer in the flow for comparison with the experiment. At higher [NH3], when dimerization was observed, the calculations significantly underestimated the degree of dimerization taking place in the flow, with a significant increase in the calculated value of kdimer required to match the experiment. The reasons for the discrepancy are discussed, for example, errors in the calculation of the density of states for the NH3 dimer and the average energy removed per collision by the bath gas at very low temperatures
How Functional Groups Influence Asphaltene Aggregation: Molecular Simulations and Small-Angle Neutron Scattering
No full textAsphaltenes are polycyclic aromatic molecules found in high-molecular-weight fractions of crude oil. They dissolve in aromatic solvents like toluene but not in aliphatic solvents like heptane. Low solubility leads to aggregate formation and many problems in transport applications. Natural asphaltene fractions contain complex mixtures of molecules that vary widely between sources of crude oil, and so the chemical and structural properties are difficult to characterize. Herein, three synthetic asphaltenes containing different oxidation states of sulfur in binary mixtures of toluene and heptane are studied. Aggregate formation is investigated using a combination of small-angle neutron scattering (SANS) and molecular dynamics (MD) simulations. The extent of aggregation is found to depend strongly on both the composition of the solvent and the functionality of the sulfur atom. A benzothiophene-functionalized asphaltene, without any oxygen, forms nanoaggregates in toluene that do not change significantly on addition of heptane. In contrast, asphaltenes containing the sulfoxide or sulfone analogs form nanoaggregates in toluene and much larger clusters above 40% by volume heptane content, with the initial nanoaggregates of the sulfone being slightly larger. Such behavior is apparent in both measured and simulated scattering profiles, and while these techniques probe different length scales, the results are consistent. The microscopic structures of the simulated aggregates are detailed. In systems with low heptane content, the asphaltenes form small clusters of 2-4 molecules, depending on the functionality. In systems with greater heptane content, the sulfoxide and sulfone form larger clusters. The variations in clustering behavior between functional groups and solvents are attributed mainly to the electrostatic interactions between the polar sulfur-containing functional groups, which stabilize “head-to-tail” configurations in the sulfoxide aggregates and more complex branched structures in the sulfone aggregates
Culture and interculturality as non-/sharing: Meaning-making beyond discourse
No full textI present a sociosemiotic approach to culture/interculturality reconceptualised as non-/sharing in semiotic practices. I illustrate the non-/sharing dimensions and degrees derived from attributions of provenance in food-related Facebook groups. Several socialisation dimensions compete and combine in interaction, opening lines of flight challenging essentialised boundaries and ideas of multi/interculturality as necessarily tied to nationalities/ethnicities and/or mother tongues. The approach provides an analytical lens/toolkit to examine diversity and sharing co-construction in semiotic resources/practices in any communicative contexts, making it useful vis-a-vis a landscape of growing nationalisms and anti-immigration propaganda on one hand, and internal societal divisions and polarisations on the other.
L’articolo presenta un approccio sociosemiotico che riconcettualizza cultura/interculturalità in termini di non-/condivisione di pratiche semiotiche, articolato in dimensioni e gradi di non-/condivisione derivati dalle attribuzioni di provenienza in gruppi Facebook dedicati al cibo. Diverse dimensioni di socializzazione competono e si combinano nell’interazione, aprendo linee di fuga che minano confini essenzializzati, nonché concezioni di multi/interculturalità necessariamente legate a nazionalità/etnie/lingue. L’approccio fornisce una lente analitica per esaminare diversità e co-costruzione di condivisione in risorse/pratiche semiotiche in ogni contesto comunicativo, utile di fronte a un panorama crescente di nazionalismi e propaganda anti-immigrazione da un lato, e di divisioni interne e polarizzazioni sociali dall’altro
