Performance of Concrete Pavements Containing Recycled Concrete Aggregate

DTFH61-93-C-00133This interim report documents the field performance of nine concrete pavement projects that incorporate recycled concrete aggregate (RCA) in the construction of the pavement. Multiple sections were evaluated on many of the nine projects, due to perceived differences in performance levels or variations in pavement design (such as the use of virgin aggregate or the inclusion of dowel bars). All told, a total of 17 sections (of which 12 contain RCA) were subjected to an extensive field testing program, consisting of pavement condition surveys, drainage surveys, falling weight deflectometer (FWD) testing, coring, and serviceability assessments. A minimum of eight cores were retrieved from each section for laboratory evaluation of compressive strength, split tensile strength, dynamic elastic modulus, static elastic modulus, and thermal coefficient of expansion, as well as for volumetric surface testing and petrographic analyses. Each of the 17 sections included in the investigation is described in detail. Performance observations and results from the FWD and laboratory testing are presented, with emphasis on evaluating the effect of RCA on pavement performance. An overall summary is provided that synthesizes the findings and conclusions of the field testing program. A laboratory-based research effort is currently being planned to provide additional insight on the behavior of concrete mixtures using RCA. Those laboratory-based results, taken in conjunction with the results of the field testing program, will be used to produce guidelines for the design of recycled concrete mixtures and to develop recommendations for the design of concrete pavements using RCA

Evolution of laparoscopic left lateral sectionectomy without the Pringle maneuver: through resection of benign and malignant tumors to living liver donation

BACKGROUND: Laparoscopic left lateral sectionectomy (LLS) has gained popularity in its use for benign and malignant tumors. This report describes the evolution of the authors' experience using laparoscopic LLS for different indications including living liver donation. METHODS: Between January 2004 and January 2009, 37 consecutive patients underwent laparoscopic LLS for benign, primary, and metastatic liver diseases, and for one case of living liver donation. Resection of malignant tumors was indicated for 19 (51%) of the 37 patients. RESULTS: All but three patients (deceased due to metastatic cancer disease) are alive and well after a median follow-up period of 20 months (range, 8-46 months). Liver cell adenomas (72%) were the main indication among benign tumors, and colorectal liver metastases (84%) were the first indication of malignancy. One case of live liver donation was performed. Whereas 16 patients (43%) had undergone a previous abdominal surgery, 3 patients (8%) had LLS combined with bowel resection. The median operation time was of 195 min (range, 115-300 min), and the median blood loss was of 50 ml (range, 0-500 ml). Mild to severe steatosis was noted in 7 patients (19%) and aspecific portal inflammation in 11 patients (30%). A median free margin of 5 mm (range, 5-27 mm) was achieved for all cancer patients. The overall recurrence rate for colorectal liver metastases was of 44% (7 patients), but none recurred at the surgical margin. No conversion to laparotomy was recorded, and the overall morbidity rate was 8.1% (1 grade 1 and 2 grade 2 complications). The median hospital stay was 6 days (range, 2-10 days). CONCLUSIONS: Laparoscopic LLS without portal clamping can be performed safely for cases of benign and malignant liver disease with minimal blood loss and overall morbidity, free resection margins, and a favorable outcome. As the ultimate step of the learning curve, laparoscopic LLS could be routinely proposed, potentially increasing the donor pool for living-related liver transplantation

New ideas for non-animal approaches to predict repeated-dose systemic toxicity: Report from an EPAA Blue Sky Workshop

© 2020 The Authors The European Partnership for Alternative Approaches to Animal Testing (EPAA) convened a ‘Blue Sky Workshop’ on new ideas for non-animal approaches to predict repeated-dose systemic toxicity. The aim of the Workshop was to formulate strategic ideas to improve and increase the applicability, implementation and acceptance of modern non-animal methods to determine systemic toxicity. The Workshop concluded that good progress is being made to assess repeated dose toxicity without animals taking advantage of existing knowledge in toxicology, thresholds of toxicological concern, adverse outcome pathways and read-across workflows. These approaches can be supported by New Approach Methodologies (NAMs) utilising modern molecular technologies and computational methods. Recommendations from the Workshop were based around the needs for better chemical safety assessment: how to strengthen the evidence base for decision making; to develop, standardise and harmonise NAMs for human toxicity; and the improvement in the applicability and acceptance of novel techniques. “Disruptive thinking” is required to reconsider chemical legislation, validation of NAMs and the opportunities to move away from reliance on animal tests. Case study practices and data sharing, ensuring reproducibility of NAMs, were viewed as crucial to the improvement of non-animal test approaches for systemic toxicity.U.S.Environmental Protection Agency (EPA); Agency for Science, Technology and Research ( A*STAR), Singapor

Cold atoms in space: community workshop summary and proposed road-map

We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies

Non-smoke spontaneous contrast in left atrium intensified by respiratory manoeuvres: a new transoesophageal echocardiographic observation.

OBJECTIVE--To elucidate why different types of contrast appear in the left atrium during transoesophageal echocardiographic contrast studies. This should lead to a more uniform definition of true patent foramen ovale. BACKGROUND--The Valsalva manoeuvre and cough are routinely used to enhance right to left shunt for the detection of patent foramen ovale. No information is, however, available on the effect of these manoeuvres on the intrinsic echogenicity of blood in the left atrium. METHODS--30 consecutive patients referred for transoesophageal echocardiography were studied. Gain settings were relatively high so that no details were lost. The appearance of contrast during normal respiration, cough, and the Valsalva manoeuvre was looked for in the left atrium with and without venous injection of 10 ml of 5% dextrose. Frequency of contrast appearance in the left atrium was expressed as a percentage. Intensity of contrast, when present, was graded 1 (mild), 2 (moderate), or 3 (equal to right atrial contrast during injection). Timing was assessed in cardiac cycles after the end of respiratory manoeuvres. RESULTS--Left atrial contrast appeared as a "snowstorm" flowing from the right pulmonary veins towards the middle of the left atrium. It was present respectively with and without contrast injection in eight and five patients during normal respiration, in 15 and seven during a cough, and in 20 and 14 during the Valsalva manoeuvre. When present, the mean intensity of contrast was 1.0 during normal respiration, 1.4 during a cough, and 1.4 during the Valsalva manoeuvre. The mean delay of contrast appearance was 3-4 cycles after release of the Valsalva manoeuvre and after onset of cough. CONCLUSIONS--Respiratory manoeuvres frequently induce the transient appearance of mild to moderate contrast in the left atrium, most often independently of venous injections. Mild contrast was seen only with high gain settings. This contrast is likely to be related to transient stasis in the pulmonary circulation. In some cases peripheral venous injections of dextrose solution produced, without any respiratory manoeuvre, a similar contrast after the first four cardiac cycles of the right atrium filling, which is likely to represent recirculation of the injected bolus through the pulmonary capillary bed. Therefore respiratory manoeuvres should always be performed before contrast injections to allow better distinction between this background and true patent foramen ovale or pulmonary arteriovenous fistula