11 research outputs found

    Laboratory assessment of asphalt concrete durability utilizing balance mix design

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    The national highway network is vital to promote social and economic development in the United States; thus, it is essential to guarantee its durability. Better durability of asphalt concrete (AC) pavements would translate into less maintenance and repair, better ridership quality, and reduced environmental impacts. However, in the current design practice for AC materials, little attention is given to study AC performance and its implications for future durability. Additionally, budget and ecological constraints are continually requiring of pavement engineers to include increasing amounts of alternative materials into AC mixes; their impact on future mix performance, however, might not be captured by current testing approaches. Therefore, improving the tools available to assess AC durability is crucial. This research studied the laboratory performance of a high-quality Stone Matrix Asphalt (SMA), designed by the Danish Road Directorate, and that of a conventional Illinois dense-graded mix, blended with different dosages of rejuvenator to enhance its performance. The effect of short-term aging on the rejuvenated AC blends was also considered in this research. This study focused on assessing the cracking and rutting potential of the studies mixes using the Illinois Flexibility Index Test (I-FIT) and the Hamburg Wheel Track Test (HWTT). Additionally, mix stiffness and moisture damage susceptibility were evaluated using the output data from I-FIT and HWTT, respectively. The tests results were analyzed using the Illinois Balance Mix Design (I-BMD) approach to evaluate the tradeoffs between flexibility and rutting improvements. This study found that adding rejuvenator to AC does improve its flexibility characteristics; however, the impact becomes less significant with increasing dosage. However, the flexibility index (FI) exhibited by the SMA was the highest amongst the mixes considered in this study. Aging negatively affects FI, but its impact is somewhat limited. Regarding rutting resistance both types of mixes exhibited similar final rut depths; however, at higher dosages of rejuvenator the dense-graded AC mix becomes excessively soft and experiences rapid failure. Rutting resistance was found to be much more sensitive to the effects of both aging and rejuvenation that FI. Analysis of the moisture susceptibility data revealed that the SMA and the un-modified dense-graded AC mixes were less impacted by moisture damage compared to AC mixes with higher dosages of rejuvenator

    Development of Long-Term Aging Protocol for Implementation of the Illinois Flexibility Index Test (I-FIT)

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    The objective of this study was to evaluate long-term aging effects on asphalt mixtures using the Illinois Flexibility Index Test (I-FIT) and to develop a corresponding long-term aging protocol. The study recommended the use of the forced-draft oven as the aging equipment because of its availability, feasibility, practicability, capacity, and acceptable variability. A fully prepared semi-circular I-FIT specimen was chosen as the state of material during aging because it is practical, has limited operational variability, and its integrity is maintained during aging. The aging of compacted specimens for three days at 203°F (95°C) was found to be similar to aging for five days at 185°F (85°C) according to AASHTO R30, which is believed to be able to simulate up to 10 years of field aging. Hence, the 3D/95C aging method was chosen as the key component of the long-term aging protocol. Based on statistical analysis and oven-aging specimens immersed in argon, it was shown that the trends of aging after 1D/95C were similar to that observed after 3D/95C and 5D/85C. Hence, 1D/95C may be used as an indicator of 3D/95C aging for quality control purposes. Aging protocols were developed for laboratory-produced laboratory-compacted (LPLC) and plant-produced laboratory-compacted (PPLC) specimens. For LPLC, I-FIT on unaged and 3D/95C aged specimens should be conducted in all cases. A specific mix must have a mean flexibly index (FI) of unaged and 3D/95C aged specimens greater than 8.0 and 5.0, respectively, to be accepted. For PPLC, I-FIT procedure should be conducted on both unaged and 3D/95C aged specimens in all cases, while 1D/95C may be used by contractors to screen problematic mixes. Flexibility index higher than 8.0 and 4.0 for unaged and 3D/95C aged specimens, respectively, must be satisfied.IDOT-R27-175Ope

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    © 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research

    Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

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    © 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit
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