Observations on the desiccation and cracking of clay layers

Waterways and lakes in low-lying delta areas require regular dredging for maintenance. Often these sediments are placed on land, where they are allowed to ripen through a combination of drainage, consolidation and evaporation. When cracks develop during desiccation, the physical response of the soil is affected by changes in the overall strength, stiffness and permeability of the material. To better identify how cracks form and propagate, a series of tests was carried out in a controlled laboratory environment on samples of drying clay slurries under different initial and boundary conditions. The outcomes of this study indicate that the results from laboratory small scale models must be carefully analyzed, as they depend on the area and the thickness of the sample. However, common features from the different tests can be identified, which are mostly related to the intrinsic behavior of the material. For instance, the water content at which cracks initiate depends mostly on the drying rate and not only on the initial water content. Typically for the clayey soil investigated, the cracking water content is well above the shrinkage limit and in some instances even above the liquid limit. Cracks can form anywhere a defect is encountered, but it was observed that they propagate in horizontal directions below the soil surface. On the soil surface they tend to intersect with each other perpendicularly, suggesting that they are dominated by a tensile stress regime. Shear stresses also influence the response, but mainly near the boundaries of the samples, due to the interface friction

Testing the Applicability of a Checklist-Based Startle Management Method in the Simulator

Several checklist-based methods have been proposed to help pilots manage startle in unexpected situations. In the current experiment, we tested how pilots reacted to using such a method, which featured the mnemonic COOL: Calm down – Observe – Outline – Lead. Using a motion-based simulator outfitted with a non-linear aerodynamic model of a small twin-propeller aircraft, twelve pilots practiced using the COOL method before performing four test scenarios involving startling events. Application of the full method in the test scenarios was high (90-100%), and pilots rated the method on average as useful (4 on a 1-5 point Likert scale). The first two steps of the method were seen as the “core” of the method. However, pilots also displayed difficulty with prioritizing dealing with immediate threats over executing the method. The results are promising, but they also warn us to be cautious when introducing a startle management method

A multi-phase biogeochemical model for mitigating earthquake-induced liquefaction via microbially induced desaturation and calcium carbonate precipitation

A next-generation biogeochemical model was developed to explore the impact of the native water source on microbially induced desaturation and precipitation (MIDP) via denitrification. MIDP is a non-disruptive, nature-based ground improvement technique that offers the promise of cost-effective mitigation of earthquake-induced soil liquefaction under and adjacent to existing structures. MIDP leverages native soil bacteria to reduce the potential for liquefaction triggering in the short term through biogenic gas generation (treatment completed within hours to days) and over the longer term through calcium carbonate precipitation (treatment completed in weeks to months). This next-generation biogeochemical model expands earlier modeling to consider multi-phase speciation, bacterial competition, inhibition, and precipitation. The biogeochemical model was used to explore the impact of varying treatment recipes on MIDP products and by-products in a natural seawater environment. The case study presented herein demonstrates the importance of optimizing treatment recipes to minimize unwanted by-products (e.g., H2S production) or incomplete denitrification (e.g., nitrate and nitrite accumulation).</p

Exploring the pharmacists' role in optimising antithrombotic therapy in primary care: A qualitative study

Objective In antithrombotic therapy, the balance between efficacy and safety is delicate, which makes it challenging for healthcare professionals, including pharmacists, to optimise therapy. Pharmacists may play an important role in optimising antithrombotic therapy, but especially in primary care, this role has not been elucidated. Here, we study how community pharmacists (pharmacists in primary care) perceive their current and future role in antithrombotic therapy. Design We conducted a qualitative study using semi-structured interviews. The interview protocol and subsequent analysis were based on the Theoretical Domains Framework, and the findings were interpreted with the Capability Opportunity Motivation - Behaviour System. Setting and participants The interview participants were community pharmacists, located across the Netherlands, from the Utrecht Pharmacy Practice network for Education and Research. Results We interviewed 16 community pharmacists between February and August 2021 and identified several major themes which were important for the pharmacist's role in antithrombotic therapy. Pharmacists felt responsible for the outcome of antithrombotic treatment and intended to invest in their role in antithrombotic therapy. Pharmacists did, however, experience barriers to their role in antithrombotic therapy, like a lack of access to clinical information such as the indication of antithrombotic treatment and a lack of specific knowledge on this treatment. Conclusion Community pharmacists perceive a role for themselves in antithrombotic therapy. To fulfil this role, several preconditions must be met

Evaluation of materials for retention of sodium and core debris in reactor systems. Annual progress report, September 1977-December 1978. [LMFBR]

This report considers some of the consequences of a hypothetical core disruptive accident in a nuclear reactor. The interactions expected between molten core debris, liquid sodium, and materials that might be employed in an ex-vessel sacrificial-bed or in the reactor building are discussed. Experimental work performed for NRC by Sandia Laboratories and Hanford Engineering Development Laboratory on the interactions between liquid sodium and basalt concrete is reviewed. Studies of molten steel interactions with concrete at Sandia Laboratories and molten UO/sub 2/ interactions with concrete at The Aerospace Corporation are also discussed. The potential of MgO for use in core containment is discussed and refractory materials other than MgO are reviewed. Finally, results from earlier experiments with molten core debris and various materials performed at The Aerospace Corporation are presented

Perceptions of HIV cure and willingness to participate in HIV cure-related trials among people enrolled in the Netherlands cohort study on acute HIV infection

BACKGROUND: People who initiate antiretroviral therapy (ART) during acute HIV infection are potential candidates for HIV cure-related clinical trials, as early ART reduces the size of the HIV reservoir. These trials, which may include ART interruption (ATI), might involve potential risks. We explored knowledge and perception of HIV cure and willingness to participate in cure-related trials among participants of the Netherlands Cohort Study on Acute HIV infection (NOVA study), who started antiretroviral therapy immediately after diagnosis of acute HIV infection. METHODS: We conducted 20 in-depth qualitative interviews with NOVA study participants between October–December 2018. Data were analyzed thematically, using inductive and iterative coding techniques. FINDINGS: Most participants had limited knowledge of HIV cure and understood HIV cure as complete eradication of HIV from their bodies. HIV cure was considered important to most participants, mostly due to the stigma surrounding HIV. More than half would consider undergoing brief ATI during trial participation, but only one person considered extended ATI. Viral rebound and increased infectiousness during ATI were perceived as large concerns. Participants remained hopeful of being cured during trial participation, even though they were informed that no personal medical benefit was to be expected. INTERPRETATION: Our results highlight the need for thorough informed consent procedures with assessment of comprehension and exploration of personal motives prior to enrollment in cure-related trials. Researchers might need to moderate their expectations about how many participants will enroll in a trial with extended ATI

Prospective and systematic screening for invasive aspergillosis in the ICU during the COVID-19 pandemic: a proof of principle for future pandemics

The diagnostic performance of a prospective, systematic screening strategy for COVID-19 associated pulmonary aspergillosis (CAPA) during the COVID-19 pandemic was investigated. Patients with COVID-19 admitted to the ICU were screened for CAPA twice weekly by collection of tracheal aspirate (TA) for Aspergillus culture and PCR. Subsequently, bronchoalveolar lavage (BAL) sampling was performed in patients with positive screening results and clinical suspicion of infection. Patient data were collected from April 2020–February 2022. Patients were classified according to 2020 ECMM/ISHAM consensus criteria. In total, 126/370 (34%) patients were positive in screening and CAPA frequency was 52/370 (14%) (including 13 patients negative in screening). CAPA was confirmed in 32/43 (74%) screening positive patients who underwent BAL sampling. ICU mortality was 62% in patients with positive screening and confirmed CAPA, and 31% in CAPA cases who were screening negative. The sensitivity, specificity, positive and negative predictive value (PPV & NPV) of screening for CAPA were 0.71, 0.73, 0.27, and 0.95, respectively. The PPV was higher if screening was culture positive compared to PCR positive only, 0.42 and 0.12 respectively. CAPA was confirmed in 74% of screening positive patients, and culture of TA had a better diagnostic performance than PCR. Positive screening along with clinical manifestations appeared to be a good indication for BAL sampling since diagnosis of CAPA was confirmed in most of these patients. Prospective, systematic screening allowed to quickly gain insight into the epidemiology of fungal superinfections during the pandemic and could be applicable for future pandemics. Medical Microbiolog

Management of adult-onset Still's disease:evidence- and consensus-based recommendations by experts

Objectives: Adult-onset Still's disease (AOSD) is a rare condition characterized by fevers, rash, and arthralgia/arthritis; most doctors treating AOSD in the Netherlands treat &lt;5 patients per year. Currently, there is no internationally accepted treatment guideline for AOSD. The objectives of this study were to conduct a Delphi panel aimed at reaching consensus about diagnostic and treatment strategies for patients with AOSD and to use the outcomes as a basis for a treatment algorithm. Methods: The Delphi panel brought together 18 AOSD experts: rheumatologists, internists and paediatricians. The Delphi process consisted of three rounds. In the first two rounds, online lists of questions and statements were completed. In the third round, final statements were discussed during a virtual meeting and a final vote took place. Consensus threshold was set at 80%. Two targeted literature searches were performed identifying the level of evidence of the consensus-based statements. Results: Consensus was reached on 29 statements, including statements related to diagnosis and diagnostic tests, definition of response and remission, the therapy, the use of methotrexate and tapering of treatment. The panel consented on reduction of the use of glucocorticoids to avoid side effects, and preferred the use of biologics over conventional treatment. The role of IL-1 and IL-6 blocking agents was considered important in the treatment of AOSD. Conclusion: In this Delphi panel, a high level of consensus was achieved on recommendations for diagnosis and therapy of AOSD that can serve as a basis for a treatment guideline.</p

Management of adult-onset Still's disease:evidence- and consensus-based recommendations by experts

Objectives: Adult-onset Still's disease (AOSD) is a rare condition characterized by fevers, rash, and arthralgia/arthritis; most doctors treating AOSD in the Netherlands treat &lt;5 patients per year. Currently, there is no internationally accepted treatment guideline for AOSD. The objectives of this study were to conduct a Delphi panel aimed at reaching consensus about diagnostic and treatment strategies for patients with AOSD and to use the outcomes as a basis for a treatment algorithm. Methods: The Delphi panel brought together 18 AOSD experts: rheumatologists, internists and paediatricians. The Delphi process consisted of three rounds. In the first two rounds, online lists of questions and statements were completed. In the third round, final statements were discussed during a virtual meeting and a final vote took place. Consensus threshold was set at 80%. Two targeted literature searches were performed identifying the level of evidence of the consensus-based statements. Results: Consensus was reached on 29 statements, including statements related to diagnosis and diagnostic tests, definition of response and remission, the therapy, the use of methotrexate and tapering of treatment. The panel consented on reduction of the use of glucocorticoids to avoid side effects, and preferred the use of biologics over conventional treatment. The role of IL-1 and IL-6 blocking agents was considered important in the treatment of AOSD. Conclusion: In this Delphi panel, a high level of consensus was achieved on recommendations for diagnosis and therapy of AOSD that can serve as a basis for a treatment guideline.</p