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1.
Phys Chem Chem Phys ; 21(27): 14964-14972, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31237285

RESUMO

Extensive Monte Carlo simulations of lithium oxide, Li2O, an important material for fusion applications over a wide range of temperatures have been performed. In the low temperature range 1-500 K, quantum path-integral corrections to the enthalpy and unit cell size were determined. We show that classical Monte Carlo underestimates both these quantities and the difference between unit cell parameters with and without quantum corrections is large enough that such corrections should be included in any comparison between theory and experiment. Over the range 300-1000 K, the formation energies of Schottky and Frenkel defects are calculated and compared with those from direct free energy minimisation in the quasiharmonic approximation, which also includes quantum corrections; the Monte Carlo results highlight the onset of failure of the quasiharmonic approximation even at modest temperatures and suggest only a small variation of the defect enthalpies with temperature. Several possible diffusion mechanisms are identified. While an interstitialcy mechanism activates at around 900-1000 K, lithium vacancy migration dominates from 500 K. The estimated migration energy of the Li-vacancy jump (0.28 eV) agrees very well with the most recent NMR study. At temperatures above 1000 K, the superionic phase transition and subsequent melting are simulated and there is good agreement with available experimental data. Our simulations predict a rapid rise in the heat capacity and the thermal expansion coefficient which continues up to the melting point which leaves two interesting questions for future experimental studies: (i) whether above the superionic transition the heat capacity and the thermal expansion coefficient in antifluorite Li2O rise up to the melting point, as in our simulations, or fall, as observed in several fluorites, and (ii) the subsequent change in the heat capacity during melting.

2.
J Oncol ; 2019: 4878547, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32082376

RESUMO

Glioblastoma is the most common primary adult brain tumour, and despite optimal treatment, the median survival is 12-15 months. Patients with matched recurrent glioblastomas were investigated to try to find actionable mutations. Tumours were profiled using a validated DNA-based gene panel. Copy number variations (CNVs) and single nucleotide variants (SNVs) were examined, and potentially pathogenic variants and clinically actionable mutations were identified. The results revealed that glioblastomas were IDH-wildtype (IDH WT; n = 38) and IDH-mutant (IDH MUT; n = 3). SNVs in TSC2, MSH6, TP53, CREBBP, and IDH1 were variants of unknown significance (VUS) that were predicted to be pathogenic in both subtypes. IDH WT tumours had SNVs that impacted RTK/Ras/PI(3)K, p53, WNT, SHH, NOTCH, Rb, and G-protein pathways. Many tumours had BRCA1/2 (18%) variants, including confirmed somatic mutations in haemangioblastoma. IDH WT recurrent tumours had fewer pathways impacted (RTK/Ras/PI(3)K, p53, WNT, and G-protein) and CNV gains (BRCA2, GNAS, and EGFR) and losses (TERT and SMARCA4). IDH MUT tumours had SNVs that impacted RTK/Ras/PI(3)K, p53, and WNT pathways. VUS in KLK1 was possibly pathogenic in IDH MUT. Recurrent tumours also had fewer pathways (p53, WNT, and G-protein) impacted by genetic alterations. Public datasets (TCGA and GDC) confirmed the clinical significance of findings in both subtypes. Overall in this cohort, potentially actionable variation was most often identified in EGFR, PTEN, BRCA1/2, and ATM. This study underlines the need for detailed molecular profiling to identify individual GBM patients who may be eligible for novel treatment approaches. This information is also crucial for patient recruitment to clinical trials.

3.
Eur J Appl Physiol ; 83(1): 77-83, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11072777

RESUMO

The reliability and validity of a soccer-specific field test of repeated sprint ability was assessed. Seven male games players performed the repeated sprint test on six separate occasions. The temporal pattern of the mean sprint time was analysed by using coefficient of variation with confidence intervals (CI), and repeated measures ANOVA. A within subject mean coefficient of variation of 1.8% (95% CI, 1.5-2.4) was found for performance in the repeated sprint test across all six trials. The mean coefficient of variation across trials 2-4 was found to be 1.9% (95% CI, 1.3-3.1), compared to trials 4-6, where it was 1.4% (95% CI, 1.0-2.3). The ANOVA showed that a significant difference was present between the trials (F6,30 9.8. P<0.001). A Tukey post-hoc test showed that significant differences were present between trial I and trials 3-6, and trial 2 and trial 5. The learning effect was complete by trial 3. Performance in the repeated sprint test was compared to total running time averaged from two repeats of the maximal anaerobic running test laboratory protocol. Mean sprint time in the repeated sprint test and total running time in the laboratory protocol had a correlation coefficient of r = -0.298 (P = 0.516, n = 7), suggesting that the energetics of the two tests are not closely related. In conclusion, this soccer-specific field test demonstrated high reliability.


Assuntos
Teste de Esforço/métodos , Corrida/fisiologia , Futebol/fisiologia , Adulto , Teste de Esforço/estatística & dados numéricos , Humanos , Masculino , Reprodutibilidade dos Testes
4.
Ergonomics ; 36(1-3): 169-75, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8440215

RESUMO

The Circadian Type Inventory (Folkard 1987) was administered to 191 students (150 females and 41 males). Corrected item to total correlations for both the Vigour and Rigidity scales were low to moderate. The internal reliabilities of the scales indicate that Vigour is statistically more homogeneous (0.74) than Rigidity (0.58). In the absence of the original CTI correlation matrix, replication using a 2-factor principal component varimax solution was undertaken. It explained only 26.7% of the variance. Post hoc factor analyses yielded 3 factors which explained 33.4% of the variance. The relatively low amounts of variance explained and the inadequate transfer of the circadian constructs of Rigidity and Vigour into question items does not recommend the use of the CTI to measure circadian rhythm characteristics in order to predict tolerance to shiftwork.


Assuntos
Ritmo Circadiano , Individualidade , Inventário de Personalidade/estatística & dados numéricos , Adolescente , Adulto , Análise Fatorial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria , Reprodutibilidade dos Testes , Sono , Fases do Sono , Tolerância ao Trabalho Programado
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