182 research outputs found
banahCEM – comparison of properties of a laterite-based geopolymer with conventional concrete
Comparison of lithomarge and cement-based mortars performance in aggressive aqueous environments
The resistance of room temperature cured geopolymer mortar (GPM) against chemical attacks, i.e. sodium and magnesium sulfate solutions, and sulfuric and hydrochloric acid solutions, was evaluated. GPM was formulated using a lithomarge precursor (low-purity kaolin) to achieve 28-day characteristic compressive strength of 60 MPa. Its performance was compared with an equivalent Portland cement mortar (PCM) having the same paste volume and strength grade. 28-day old bar samples were stored in 0.352 mol/L sulfate solutions for 52 weeks whereas 28-day old cube samples were exposed for 8 weeks to acid solutions with concentration of 0.52 mol/L. GPM showed superior performance against sulfate attack when compared to PCM. No visual deterioration was observed in GPM, the length changes were relatively small, and no changes to the microstructure were detected – in contrast to severely deteriorated PCM. As confirmed by visual observations and lower mass loss, GPM showed better resistance to attack by both acids than PCM. GPM provided a better quality (lower permeability) of an acid-degraded layer, lowering the degree of further deterioration. The main mechanisms of the matrix deterioration of GPM in both acids was dealumination of the hardened binder, with a higher degree of changes detected for sulfuric acid
Cäsium-Sorptionsuntersuchungen an graphitischen Reaktorwerkstoffen
A Knudsen cell-mass spectrometer System has been developed for vapour pressure measurements to determine the sorption isotherms of Cs for graphitic reactor materials. Double Knudsen cells heated by high frequency were employed in this system. A highvacuum furnace with a specially designed oven-cell was used for isopiestic experiments carried out in addition ta the mass spectrometric studies. The Cs equilibrium partial pressure was measured at temperatures 950 and 1820 K oves A3-3 fuel elementmatrix with Cs concentrations between 0.17 and 34.76 mma1/kg. Sorptionisotherms of Cs according to Henry and Freundlich wereevaluated from the vapour pressure data. The sorption enthalpies for CsTob tained indicahte a strong boned by chemisorption. Cssorption of the "reactor graphites" A3-3, A3-27, ASR -1RG, ASR-1RS, ASR-2RS, PAN, P3-JHAN, PXA-2N, H-451, H-327, IG-110 and thecoat-mix materials Cm-100 and Cm-30 resulted by the isopiestic method. It could be shown that graphitic reactor materials wich phenolic resin binder are able to bind a substantially higher amount of Cs by sorption than "reactor graphites" without this binder. More information about the content of this report is given in chapter 8 "Zusammenfassung und Ausblick" (Summary and outlook)
Radiological evaluation of industrial residues for construction purposes correlated with their chemical properties
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThis study characterises the naturally occurring radionuclide (NOR) contents of a suite of secondary raw materials or industrial residues that are normally disposed of in landfills or lagoons but now are increasingly used in green concretes. This includes ashes from a variety of industrial processes and red mud from aluminium production, as well as air pollution control residue and cement kiln dust. The chemical composition of the samples was determined with X-ray fluorescence spectroscopy (XRF). The Ra-226, Th-232 and K-40 activity concentrations were obtained by gamma spectrometry, and the results were compared with recently published NOR databases. The correlation between the NOR contents and the main chemical composition was investigated. The radioactive equilibrium in the U-238 chain was studied based on the determination of progeny isotopes. The most commonly used calculation methods (activity concentration index and radium equivalent concentration) were applied to classify the samples. The radon exhalation rate of the samples was measured, and the radon emanation coefficient was calculated. Significant correlation was found between the NORs and certain chemical components. The massic exhalation demonstrated a broad range, and it was found that the emanation coefficients were significantly lower in the case of the residues generated as a result of high-temperature combustion processes. The results showed a weak correlation between the Ra-226 concentration and the radon exhalation. This emphasises that managing the Ra-226 content of recycled material by itself is not sufficient to control the radon exhalation of recycled materials used in building products. The investigated parameters and their correlation behaviour could be used to source apportion materials found during the process of landfill mining and recovery of material for recycling.European Union Horizon 202
Change in health literacy over a decade in a prospective cohort of community-dwelling older adults
BACKGROUND: Health literacy is often viewed as a static trait in longitudinal studies, which may over or underestimate an individual’s ability to manage one’s health. OBJECTIVES: We sought to examine health literacy over time among older adults using three widely used measures. DESIGN: A prospective cohort study. PARTICIPANTS: Community-dwelling adults ages 55 to 74 at baseline with at least one follow-up visit (N = 656) recruited from one academic internal medicine clinic and six community health centers in Chicago, IL. MEASURES: Health literacy was measured using the Test of Functional Health Literacy in Adults (TOFHLA), Newest Vital Sign (NVS), and Rapid Estimate of Adult Literacy in Medicine (REALM) at baseline and up to three follow-up time points. RESULTS: In unadjusted analyses, significant changes since baseline were found beginning at the second follow-up (mean (M) = 6.0 years, SD = 0.6) for the TOFHLA (M = − 0.9, SD = 0.95, p = 0.049) and the REALM (M = 0.3, SD = 2.5, p = 0.004) and at the last follow-up (M = 8.6 years, SD = 0.5) for the NVS (M = − 0.2, SD = 1.4, p = 0.02). There were non-linear effects of baseline age on TOFHLA and NVS scores over time (piecewise cubic spline p = 0.01 and p < 0.001, respectively) and no effect on REALM scores (B = 0.02, 95% CI − 0.01 to 0.04, p = 0.17) using multivariable mixed-effects linear regression models, controlling for race, education, income, and comorbidity. CONCLUSION: We found a negative relationship between age and health literacy over time as measured by the TOFHLA and NVS. Health literacy barriers appear to be more prevalent among individuals in later life, when self-care demands are similarly increasing. Clinicians might consider strategies to assess and respond to limited health literacy, particularly among patients 70 and older. REALM performance remained stable over 10 years of follow-up. This questions whether health literacy tools measure the same attribute. Prospective health literacy studies should carefully consider what measures to use, depending on their objective
The Hydrogel Endovascular Aneurysm Treatment Trial (HEAT): A Randomized Controlled Trial of the Second-Generation Hydrogel Coil
© 2020 Congress of Neurological Surgeons 2020. BACKGROUND: Aneurysm recurrence after coiling has been associated with aneurysm growth, (re)hemorrhage, and a greater need for follow-up. The second-generation HydroCoil Embolic System (HES; MicroVention, Inc) consists of a platinum core with integrated hydrogel and was developed to reduce recurrence through enhancing packing density and healing within the aneurysm. OBJECTIVE: To compare recurrence between the second-generation HES and bare platinum coil (BPC) in the new-generation Hydrogel Endovascular Aneurysm Treatment Trial (HEAT). METHODS: HEAT is a randomized, controlled trial that enrolled subjects with ruptured or unruptured 3- to 14-mm intracranial aneurysms amenable to coiling. The primary endpoint was aneurysm recurrence using the Raymond-Roy scale. Secondary endpoints included minor and major recurrence, packing density, adverse events related to the procedure and/or device, mortality, initial complete occlusion, aneurysm retreatment, hemorrhage from target aneurysm during follow-up, aneurysm occlusion stability, and clinical outcome at final follow-up. RESULTS: A total of 600 patients were randomized (HES, n = 297 and BPC, n = 303), including 28% with ruptured aneurysms. Recurrence occurred in 11 (4.4%) subjects in the HES arm and 44 (15.4%) subjects in the BPC arm (P =. 002). While the initial occlusion rate was higher with BPC, the packing density and both major and minor recurrence rates were in favor of HES. Secondary endpoints including adverse events, retreatment, hemorrhage, mortality, and clinical outcome did not differ between arms. CONCLUSION: Coiling of small-to-medium aneurysms with second-generation HES resulted in less recurrence when compared to BPC, without increased harm. These data further support the use of the second-generation HES for the embolization of intracranial aneurysms. Video Abstract: 10.1093/neuros/nyaa006 nyaa006Media1 613226478400
DNA Targeting as a Likely Mechanism Underlying the Antibacterial Activity of Synthetic Bis-Indole Antibiotics
We previously reported the synthesis and biological activity of a series of cationic bis-indoles with potent, broad-spectrum antibacterial properties. Here, we describe mechanism of action studies to test the hypothesis that these compounds bind to DNA and that this target plays an important role in their antibacterial outcome. The results reported here indicate that the bis-indoles bind selectively to DNA at A/T-rich sites, which is correlated with the inhibition of DNA and RNA synthesis in representative Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) organisms. Further, exposure of E. coli and S. aureus to representative bis-indoles resulted in induction of the DNA damage-inducible SOS response. In addition, the bis-indoles were found to be potent inhibitors of cell wall biosynthesis; however, they do not induce the cell wall stress stimulon in S. aureus, suggesting that this pathway is inhibited by an indirect mechanism. In light of these findings, the most likely basis for the observed activities of these compounds is their ability to bind to the minor groove of DNA, resulting in the inhibition of DNA and RNA synthesis and other secondary effects
The electronic medication complete communication (EMC2) study: Rationale and methods for a randomized controlled trial of a strategy to promote medication safety in ambulatory care
AbstractBackgroundAdverse drug events (ADEs) affect millions of patients annually and place a significant burden on the healthcare system. The Food and Drug Administration (FDA) has developed patient safety information for high-risk medications that pose serious public health concerns. However, there are currently few assurances that patients receive this information or are able to identify or respond correctly to ADEs.ObjectiveTo evaluate the effectiveness of the Electronic Medication Complete Communication (EMC2) Strategy to promote safe medication use and reporting of ADEs in comparison to usual care.MethodsThe automated EMC2 Strategy consists of: 1) provider alerts to counsel patients on medication risks, 2) the delivery of patient-friendly medication information via the electronic health record, and 3) an automated telephone assessment to identify potential medication concerns or ADEs. The study will take place in two community health centers in Chicago, IL. Adult, English or Spanish-speaking patients (N=1200) who have been prescribed a high-risk medication will be enrolled and randomized to the intervention arm or usual care based upon practice location. The primary outcomes of the study are medication knowledge, proper medication use, and reporting of ADEs; these will be measured at baseline, 4weeks, and three months. Intervention fidelity as well as barriers and costs of implementation will be evaluated.ConclusionsThe EMC2 Strategy automates a patient-friendly risk communication and surveillance process to promote safe medication use while minimizing clinic burden. This trial seeks to evaluate the effectiveness and feasibility of this strategy in comparison to usual care
Mycoplasma hominis deep wound infection after neuromuscular scoliosis surgery: the use of real-time polymerase chain reaction (PCR)
Mycoplasma hominis is a commensal of the genitourinary tract. It mostly causes infections to associated structures of this system; however, occasionally it is a pathogen in nongenitourinary tract infections. Since, M. hominis strains require special growth conditions and cannot be Gram stained, they may be missed or delay diagnosis. This report describes a deep wound infection caused by M. hominis after neuromuscular scoliosis surgery; M. hominis was recovered by real-time polymerase chain reaction (PCR). An awareness of the role of M. hominis as an extragenital pathogen in musculoskeletal infections, especially in neuromuscular scoliosis, being a high-risk group for postoperative wound infection, it is necessary to identify this pathogen. Real-time PCR for postoperative deep wound infection, in patients with a history of genitourinary infections, decreases the delay in diagnosis and treatment. In these cases rapid real-time PCR on deep cultures should be considered
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