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Structured Silicalite-1 Encapsulated Ni Catalyst Supported on SiC Foam for Dry Reforming of Methane
No full textStructured silicalite-1 zeolite encapsulated Ni catalyst supported on silicon carbide foam (i.e., Ni@S1-SiC) was prepared using a new yet simple one-pot method, showing the significantly improved anti-sintering and anti-coking performance in comparison with the conventional supported and encapsulated Ni catalysts (i.e., Ni/S1, Ni/S1-SiC, and Ni@S1), in catalytic dry reforming of methane (DRM). The developed Ni0.08@S1-SiC catalyst showed high CO2/CH4 conversions of >85% and H2/CO molar ratio of >0.85 at 700 °C, outperforming other control catalysts under investigation. Additionally, the Ni0.08@S1-SiC catalyst demonstrated high turnover frequency (TOF) values of ~5.4 and ~2.1 s−1 regarding to CO2/CH4 conversions at 400 °C, exhibiting excellent stability and low pressure-drop during 100 h on stream evaluation. Post-reaction characterisation of the used catalysts demonstrated that the combination of zeolite encapsulated Ni catalysts and SiC foam enabled well-dispersed and ultrafine Ni nanoparticles, low pressure drop and intensified transfer steps, presented excellent anti-sintering and anti-coking abilities
Association between age at first reported e-cigarette use and subsequent regular e-cigarette, ever cigarette and regular cigarette use
No full textBackground and Aims: Association of electronic cigarette use and subsequent smoking has received considerable attention, although age of first use has not. This study tested differences in regular (e-cigarettes, cigarettes) and ever (cigarettes) use between e-cigarette user groups: early versus never users, late versus never users, early versus late users and effects of controlling for covariates. Design: Prospective study with 12- and 24-month follow-up of e-cigarette/cigarette ever/regular use with data from an intervention. Setting: Forty-five schools in England (Staffordshire and Yorkshire). Participants: Never smokers (3289 13-14 year olds) who were part of a cluster randomised controlled trial. Measurements: Sample divided into groups of e-cigarette users: early users (at 13-14 years), late users (at 14-15 years), never users (at 13-14 and 14-15 years). Dependent variables were self-reported regular e-cigarette and cigarette use, ever cigarette use at 15-16 years. Covariates were assessed. Findings: Early users and late users compared with never users were significantly more likely to be regular e-cigarette users (early: OR=9.42, 95%CI=5.38, 16.49, p<.001; late: OR=6.89, 95%CI=4.11, 11.54, p<.001), ever cigarette users (early: OR=7.96, 95%CI=6.02, 10.53, p<.001; late: OR=5.13, 95%CI=3.85, 6.84, p<.001), and regular cigarette users (early: OR=7.80, 95%CI=3.99, 15.27, p<.001; late: OR=4.34, 95%CI=1.93, 9.77, p<.001) at age 15-16 years. Late users compared with early users had significantly lower rates of ever use of cigarettes at 15-16 years (OR=0.48, 95%CI=0.35, 0.66, p<.001), although this difference was non-significant at 12 months after first use of e-cigarettes (OR=0.89, 95%CI 0.64, 1.25, p = .498). Controlling for covariates did not change findings. Conclusions: Adolescents in England who report using e-cigarettes at 13-14 years of age have higher rates of subsequently initiating cigarette use than adolescents who report using e-cigarettes at 14-15 years, a difference that may be attributable to a longer period of time to initiate cigarette use in former group
Transition Metal-free Cross-Dehydrogenative Arylation of Unactivated Benzylic C–H Bonds
No full textThe cross-dehydrogenative arylation of benzylic C–H bonds with arenes provides straightforward access to synthetically useful 1,1-diarylmethanes, from readily available starting materials. Current approaches suffer from limited substrate scope, requirement for large excesses of alkyl arene and/or non-trivial reaction set up. We report a transition metal-free crossdehydrogenative arylation of benzylic C–H bonds using alkyl benzene derivatives and electron-rich arenes as coupling partners. The method proceeds through the in situ generation of a reactive benzyl fluoride intermediate which then reacts with the nucleophilic arene. The reaction tolerates a wide variety of functional groups including unprotected polar functionality and has been applied to the late-stage benzylation of several biologically relevant molecules
Expression of p53 is associated with microbial acetaldehyde production in oral squamous cell carcinoma
No full textObjectives: To investigate the association between p53 expression and microbial acetaldehyde production in patients with oral squamous cell carcinoma (OSCC). Study design: Oral mucosal biopsies from 22 patients with OSCC and 24 healthy controls (HC) were collected. p53 expression was analyzed by immunohistochemistry. Microbial samples were collected from the mucosa and microbial acetaldehyde production from ethanol was measured by gas chromatography. Results: The majority of all OSCC (77%) and HC samples (67%) produced mutagenic levels of acetaldehyde (>100 µM). A significant positive correlation between microbial acetaldehyde production and p53 expression levels in OSCC samples was seen in the intermediate and superficial layers of the epithelium of the infiltrative zone (P=0.0005 and P=0.0004, respectively) and in the superficial layer of the healthy appearing mucosa next to the tumor (P=0.0391). There was no significant correlation between acetaldehyde levels and p53 expression in HC samples. Conclusions: Our results show an association between microbial acetaldehyde production and immunostaining of p53 in OSCC samples
CA125 test result, test-to-diagnosis interval and stage in ovarian cancer: a cohort study using electronic health records
No full textBackground Cancer-Antigen-125 (CA125) is recommended as a first-line investigation in women in UK General Practice with symptoms of possible ovarian cancer. Aim To compare time between initial primary care CA125 test and diagnosis (test-to-diagnosis interval), tumour morphology and stage, in women with normal (<35U/ml) and abnormal (≥35U/ml) CA125 prior to ovarian cancer diagnosis. Design Retrospective cohort study using routinely collected primary care and cancer registry data. Methods Associations between CA125 result with test-to-diagnosis interval, stage and ovarian cancer morphology were examined. Results 351 (77%) women had an abnormal and 105 (23%) a normal initial CA125 result prior to ovarian cancer diagnosis. Median test-to-diagnosis interval was 35 days (Interquartile range [IQR]:21-53) in those with abnormal, and 64 days (IQR:42-127) in those with normal CA125s. Tumour morphology differed by CA125 result, with indolent borderline tumours being less common in those with abnormal (n=47, 13%) than normal (n=51, 49%) CA125s (p<0.001). Staging data was available for 381 women. 106 of 304 (35%) women with abnormal CA125s and 66 of 77 (86%) women with normal CA125s were diagnosed at an early stage: normal CA125s were associated with early-stage diagnosis (Odds Ratio:12.1, 95% CI:5.8-25.1, p<0.001). Conclusion Despite experiencing longer intervals between testing and diagnosis, women with normal CA125s more frequently had indolent tumours and were more commonly diagnosed at an early stage, compared to those with abnormal CA125s. Whilst more sensitive testing approaches might expedite diagnosis for some women, it is not known whether this would translate to earlier stage diagnosis and improved survival
Shockwave Characteristics of Streamer Propagation in Insulating Liquids under Positive Lightning Impulse
No full textThis paper presents an experimental study focusing on the quantitative analyses of spatial characteristics of Mach-cone shaped shockwaves generated by streamers in a mineral oil and a synthetic ester in a fixed 12 mm needle-plane gap under positive lightning impulse. The influences of voltage level and liquid type are investigated. Results showed that Mach-cone shaped shockwaves are always observed ahead of actively propagating streamer channels. In the mineral oil, instantaneous streamer velocities undergo initial bursts before gradually decreasing and stabilizing at around 2 km/s. Shockwave pressures decrease from 6-8 GPa upon the streamer initiation to around 4 GPa as streamer propagates to a longer distance. Compared to the mineral oil, the initial bursts of instantaneous streamer velocities and shockwave pressures are lower in the synthetic ester. Investigated voltage levels from initiation to near breakdown do not impose significant effects on the observed shockwave parameters. In addition, the appearance of Mach-cone shaped shockwave is found to be an effective indicator of actively propagating streamer channel which can be used as a tool to quantify streamer main branches
Do people with rheumatoid arthritis maintain their physical activity level at treatment onset over the first year of methotrexate therapy?
No full textObjectives: To describe how many people with rheumatoid arthritis (RA) reduce their baseline physical activity (PA) level over the first year of methotrexate (MTX) treatment, and which factors predict this.Methods: Data came from the Rheumatoid Arthritis Medication Study (RAMS), a prospective cohort of people with early RA starting MTX. Participants reported demographics and completed questionnaires at baseline, six and 12 months, including reporting the number of days per week they performed ≥20 minutes of PA; coded as none, low (1-3 days) or high (4-7 days). The PA levels of participants over 12 months are described. Predictors of stopping PA were assessed using multivariable logistic regression. Results: In total, 1468 participants were included (median [interquartile range] age: 60 [50, 69] years; 957 [65.2%] women). At baseline, the PA levels of the people with RA were: none = 408 (27.8%), low = 518 (35.3%), high = 542 (36.9%). 80% of participants maintained some PA or began PA between assessments (baseline to 6-months = 79.3%, 6-months to 12-months = 80.7%). 24.1% of participants reduced PA and 11.3% of participants stopped performing PA between baseline and 6-months (6-months to 12 months: 22.6% and 10.2% respectively). Baseline smoking, higher disability and greater socioeconomic deprivation were associated with stopping PA. Conclusion: Many people with early RA were not performing PA when starting MTX, or stopped performing PA over the first year of treatment. These people may require interventions to stay active. These interventions need to be mindful of socioeconomic barriers to PA participation.<br/
The Baby Steps web program for the wellbeing of new parents: A randomised controlled trial
No full textPhase Stability of the Tin monochalcogenides SnS and SnSe: a Quasi-Harmonic Lattice-Dynamics Study
No full textThe tin monochalcogenides SnS and SnSe adopt four different crystal structures, viz. orthorhombic Pnma and Cmcm andcubic rocksalt and π (𝑃2#3) phases, each of which has optimal properties for a range of potential applications. This richphase space makes it challenging to identify the conditions under which the different phases are obtained. We haveperformed first-principles quasi-harmonic lattice-dynamics calculations to assess the relative stabilities of the four phasesof SnS and SnSe. We investigate dynamical stability through the presence or absence of imaginary modes in the phonondispersion curves, and we compute Helmholtz and Gibbs free energies to evaluate the thermodynamic stability. We alsoconsider applied pressures up to 15 GPa to obtain simulated temperature-pressure phase diagrams. Finally, the relationshipsbetween the orthorhombic crystal phases are investigated by explicitly mapping the potential-energy surfaces along theimaginary harmonic phonon modes in the Cmcm phase, and the relationships between the cubic phases are found bytransition-state modelling using the climbing-image nudged elastic-band method
Insights into the Nano-Structure of Oil-Brine-Kaolinite Interfaces: Molecular Dynamics and Implications for Enhanced Oil Recovery
No full textOil-brine-clay minerals interactions play an important role in in-situ reservoir wettability, which governs the fluids flow during enhanced oil recovery, CO2 geosequestion and water remediation at subsurface. Kaolinite clay minerals are widely coated at pore surfaces at subsurface. Therefore, it is of vital importance to understand how kaolinite controls the in-situ wettability through the nanostructure of oil-brine-kaolinite interfaces. In this context, we therefore performed molecular dynamics (MD) simulation to compare the microstructures at kaolinite surfaces as a function of brine salinity in the presence of organic materials. We incorporated acid component (decanoic acid) and base component (quinoline) to evaluate the wettability alteration on kaolinite surface as a function of salinity. The species distribution and radial distribution function (g(r)) were calculated in high salinity water and low salinity water. The density profile shows that the octahedral aluminium layer is decanoic acid wet while the tetrahedral silicon layer is insensitive to both decanoic acid and quinoline regardless of salinity. The g(r) of Al and Si atoms in clay structure reveals that more water accumulates adjacent to the aluminium layer in low salinity water and screens out the ions and functional groups adsorption on the surface. However, less water accumulates around Si atoms in low salinity water than in high salinity water. The more accumulated water on octahedral layer than tetrahedral layer can explain the wettability differences on the octahedral layer and the tetrahedral layer. Furthermore, the MD results reveal that the decanoic acid is more responsive to salintiy variations than quinoline, which confirms that acid component is the primary element in oil to determine wettability alteration. This work sheds light on the significant influence of mineral surface chemical species on oil-minerals adhesion as a function of ionic strength at molecular scale. This work also provides an overall practical framework, which predicts the wettability alteration with applications in enhanced oil recovery, CO2 geosequestion and water remediation