A laboratory investigation on thermal properties of virgin and aged asphalt mixture

In this paper, the thermal properties of three dense graded asphalt mixtures, 20 mm DBM, AC 14, and AC 6, are presented. Density and air voids of the compacted specimens are also shown. Thermal conductivity was measured in the laboratory for non-aged, short-term aged and long-term aged asphalt mixtures at three different temperatures 19 (±1) oC, 65 (±5) oC, and 80 (±5) oC. Specific heat capacity and thermal diffusivity were calculated from equations derived from the literature. Heat penetration depth was also calculated and shows the heat from the thermal conductivity instrument heat source that dissipates into the asphalt specimens. The results were analysed to determine the effect of air voids content, transient line source (TLS) method, temperature and aggregate size in thermal conductivity and the effect of aging on the thermal properties of the asphalt mixtures studied. It was concluded that there is a minimal effect in thermal conductivity for 4% to 6.5% air voids. The method of measurement and temperature affect considerably thermal conductivity. However, the results were inconclusive in the effect of aggregate size on thermal conductivity. The effect of asphalt aging in thermal conductivity and thermal diffusivity varied between the asphalt mixtures studied and was relative to the temperature. Asphalt aging did not affect specific heat capacity

An innovative asphalt patch repair pre–heating method using dynamic heating

In hot mix asphalt patch repair, inadequate temperature at the interfaces is one of the influencing factors for inferior compaction and poor interface bonding. To enhance repair performance, a precisely controlled infrared pre-heating method for patch repair has been investigated. Asphalt slabs with 45 mm, 75 mm and 100 mm deep pothole excavations were subjected to dynamic heating with infrared heater operating power from 6.6 kW to 7.7 kW. The heater was kept either stationary or moving slowly across the excavations at 130 mm and 230 mm offsets. The tests included evaluating temperature increase throughout the excavations and inside the slab, recording heat power of infrared heater and heating time to avoid burning the asphalt. Irrespective of excavation depth, heating power and offset, the temperature distribution was found non-uniform in the pothole excavations and into the asphalt slab. The temperatures were higher at the faces of the excavation than inside the slab. Dynamic heating for approximately 10 min yielded better heat distribution while minimising the possibility of asphalt overheating and long pre-heating time. It has been concluded that 45 mm and 100 mm deep pothole excavations can be pre-heated with 6.6 kW and stationary heater or 7.5 kW and moving heater at 230 mm and 130 mm offset respectively. 75 mm deep excavation can be pre-heated with 7.1 kW and stationary heater at 230 mm offset

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Development of advanced temperature distribution model in hot mix asphalt patch repair

The performance of hot-mix asphalt patch repair is greatly reduced due to inferior compaction at the interface. It is known that the faster loss of temperature at the interface is one of the primary reasons for inferior compaction. A novel Controlled Pothole Repair System (CPRS) has been developed as part of this study. The CPRS uses infrared heating technology with enhanced features compared to many existing infrared systems. In parallel, a three dimensional finite element thermal model capable of modelling the loss of temperature during patch repair process has been developed. The first part of the paper presents the functionality of CPRS including experimental results to demonstrate various features of the system. In the second part, the numerical results are compared against experimentally measured values from a patch repair in a controlled laboratory condition. The tests are done to measure the influence of no preheating and preheating of the existing surface on the temperature loss. The results showed more than 80% agreement between simulation and actual measurements. It also shows, preheating of the existing surface can significantly reduce temperature loss at the interface, thus allowing more time for repair and the possibility of achieving better compaction

A África carioca em lentes européias: corpos, sinais e expressões

A proposta deste artigo é examinar as maneiras pelas quais alguns viajantes europeus que estiveram no Rio de Janeiro durante a primeira metade do século XIX diferenciaram os africanos na experiência da escravidão, tratando de um viés temático específico: os registros produzidos pela literatura de viagem oitocentista a respeito de suas belezas físicas, sinais corporais e expressões de cantos e danças. A convergência temática e valorativa desses relatos permite-nos observar a reiteração de certas tópicas que cristalizaram os significados mais comuns atribuídos pelos olhares estrangeiros aos africanismos com que depararam na cidade que continha, à época, a maior população escrava das Américas.<br>The proposal of this article is to investigate the ways some European travellers, who have came to the city of Rio de Janeiro during the first half of the 19th century, registered Africans in the slavery experience. Foreigners who visited Brazilian Court until 1850 faced the biggest African slave population of the Americas, and the set of their literature, which describes such cultural and social counterpose, reveals conceptual reiterations of a whole lot of physical and behavioural characteristics given to Africans in captivity

Cholesterol transport from late endosomes to the Golgi regulates t-SNARE trafficking, assembly, and function

This study shows that impaired cholesterol egress from late endosomes in cells with high annexin A6 levels is associated with altered soluble N-ethylmaleimide–sensitive fusion protein 23 (SNAP23) and syntaxin-4 cellular distribution and assembly and accumulation in Golgi membranes. This correlates with reduced secretion of cargo along the constitutive and SNAP23/syntaxin-4–dependent secretory pathway

Risk of COVID-19 after natural infection or vaccinationResearch in context

Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health