295 research outputs found

    Automated crack control analysis for concrete pavement construction

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    The focus of this research is on the control of random cracking in concrete paving by using sawcut notch locations in the early stages of construction. This is a major concern in concrete pavement construction. This research also addresses a probabilistic approach to determine the optimum time and depth of sawcutting for newly constructed portland cement concrete pavements. Variability in climate conditions and material characteristics during the hardening process affects the potential of cracking at any sawcut depth. Several factors affecting the probability of crack initiation are material strength parameters, method and quality of curing, slab/subbase stiffness, the amount and depth of steel reinforcement, friction between the slab and the subbase, and concrete shrinkage. Other factors relevant to concrete mixture characteristics such as cement content and type of coarse aggregate affect development of early aged stresses caused by shrinkage and thermally induced contraction. A probabilistic analysis of the factors that affect crack control using sawcut notches is presented in relation to different weather conditions (concrete placement temperature) at the time of construction, and concrete mixture characteristics such as fly ash replacement (FA) and cement factor (CF). Both of these significantly affect sawcut timing and depth requirement. The determination of crack initiation is based on fracture mechanics. Estimation of the time of cracking is based on predicted tensile strength and stress in the concrete at the bottom of the sawcut notch to assess the feasibility of crack control in the early stages of construction

    Identification of Concrete Incompatibilities Using Cement Paste Rheology

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    The complex interaction between cement and chemical/mineral admixtures in concrete mixtures sometimes leads to unpredictable concrete performance in the field which is generally defined as concrete incompatibilities. Cement paste rheology measurements instead of traditional workability tests (i.e., slump cone test) can have great potential in detecting those incompatibilities in concrete before the concrete is placed, which can, in turn, avoid related workability problems and setting time as well as heat evolution abnormalities. The objectives of the present study were to examine the applicability of the dynamic shear rheometer (DSR) to measure cement paste rheology, and to identify cement and mineral/chemical admixture incompatibilities, based on the determined rheological parameters. The DSR was modified and optimized for cement paste rheology measurements. Two different modes of operations (i.e., static and dynamic methods) with the modified DSR were investigated to measure representative rheological parameters as well as to identify cement and chemical/mineral admixture incompatibility. The conventional plastic viscosity and yield stress are measured in static mode and storage modulus curve, as a function of time, is measured in dynamic mode. The rate of change of plastic viscosity (RPV) as another static rheological parameter and the modeled magnitude parameter ?, from the dynamic rheological method, showed great potentialities as acceptance criteria to identify incompatible mixtures. The heat of hydration data from isothermal conduction calorimeter tests and setting time results for the studied mixtures have strongly supported the rheology based observations as supporting tools. Based on the main tests results, the acceptance criteria were set up using the rheological parameters in accordance with heat of hydration data. This will ultimately help material suppliers, concrete producers, and other users to detect problematic combinations of concrete ingredients before a given concrete mixture is placed

    The Sylvester Theorem and the Rogers-Ramanujan Identities over Totally Real Number Fields

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    In this paper, we prove two identities on the partition of a totally positive algebraic integer over a totally real number field which are the generalization of the Sylvester Theorem and that of the Rogers-Ramanujan Identities. Additionally, we give an another version of generalized Rogers-Ramanujan Identities

    The Euler-Glaisher Theorem over Totally Real Number Fields

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    In this paper, we study the partition theory over totally real number fields. Let KK be a totally real number field. A partition of a totally positive algebraic integer δ\delta over KK is λ=(λ1,λ2,,λr)\lambda=(\lambda_1,\lambda_2,\ldots,\lambda_r) for some totally positive integers λi\lambda_i such that δ=λ1+λ2++λr\delta=\lambda_1+\lambda_2+\cdots+\lambda_r. We find an identity to explain the number of partitions of δ\delta whose parts do not belong to a given ideal a\mathfrak a. We obtain a generalization of the Euler-Glaisher Theorem over totally real number fields as a corollary. We also prove that the number of solutions to the equation δ=x1+2x2++nxn\delta=x_1+2x_2+\cdots+nx_n with xix_i totally positive or 00 is equal to that of chain partitions of δ\delta. A chain partition of δ\delta is a partition λ=(λ1,λ2,,λr)\lambda=(\lambda_1,\lambda_2,\ldots,\lambda_r) of δ\delta such that λi+1λi\lambda_{i+1}-\lambda_i is totally positive or 00

    Sorbus alnifolia protects dopaminergic neurodegeneration in Caenorhabditis elegans

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    Context: The twigs of Sorbus alnifolia (Sieb. et Zucc.) K. Koch (Rosaceae) have been used to treat neuro- logical disorders as a traditional medicine in Korea. However, there are limited data describing the efficacy of S. alnifolia in Parkinson’s disease (PD). Objective: This study was conducted to identify the protective effects of the methanol extracts of S. alnifolia (MESA) on the dopaminergic (DA) neurodegeneration in Caenorhabditis elegans. Materials and methods: To test the neuroprotective action of MESA, viability assay was performed after 48 h exposure to 1-methyl-4-phenylpyridine (MMPþ) in PC12 cells and C. elegans (400 lM and 2 mM of MMPþ, respectively). Fluorescence intensity was quantified using transgenic mutants such as BZ555 (Pdat-1::GFP) and and UA57 (Pdat-1::GFP and Pdat-1::CAT-2) to determine MESA’s effects on DA neurode- generation in C. elegans. Aggregation of a-synuclein was observed using NL5901 strain (unc-54p::a- synuclein::YFP). MESA’s protective effects on the DA neuronal functions were examined by food-sensing assay. Lifespan assay was conducted to test the effects of MESA on the longevity. Results: MESA restored MPPþ-induced loss of viability in both PC12 cells and C. elegans (85.8% and 54.9%, respectively). In C. elegans, MESA provided protection against chemically and genetically-induced DA neurodegeneration, respectively. Moreover, food-sensing functions were increased 58.4% by MESA in the DA neuron degraded worms. MESA also prolonged the average lifespan by 25.6%. However, MESA failed to alter a-synuclein aggregation. Discussion and conclusions: These results revealed that MESA protects DA neurodegeneration and recov- ers diminished DA neuronal functions, thereby can be a valuable candidate for the treatment of PD

    Anti-allergic and anti-inflammatory effects of butanol extract from Arctium Lappa L

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    Background: Atopic dermatitis is a chronic, allergic inflammatory skin disease that is accompanied by markedly increased levels of inflammatory cells, including eosinophils, mast cells, and T cells. Arctium lappa L. is a traditional medicine in Asia. This study examined whether a butanol extract of A. lappa (ALBE) had previously unreported anti-allergic or anti-inflammatory effects.Methods: This study examined the effect of ALBE on the release of ??-hexosaminidase in antigen-stimulated-RBL-2H3 cells. We also evaluated the ConA-induced expression of IL-4, IL-5, mitogen-activated protein kinases (MAPKs), and nuclear factor (NF)-??B using RT-PCR, Western blotting, and ELISA in mouse splenocytes after ALBE treatment.Results: We observed significant inhibition of ??-hexosaminidase release in RBL-2H3 cells and suppressed mRNA expression and protein secretion of IL-4 and IL-5 induced by ConA-treated primary murine splenocytes after ALBE treatment. Additionally, ALBE (100 ??g/mL) suppressed not only the transcriptional activation of NF-??B, but also the phosphorylation of MAPKs in ConA-treated primary splenocytes.Conclusions: These results suggest that ALBE inhibits the expression of IL-4 and IL-5 by downregulating MAPKs and NF-??B activation in ConA-treated splenocytes and supports the hypothesis that ALBE may have beneficial effects in the treatment of allergic diseases, including atopic dermatitis. ?? 2011 Sohn et al; licensee BioMed Central Ltd

    Molecular Subgroup Analysis of Clinical Outcomes in a Phase 3 Study of Gemcitabine and Oxaliplatin with or without Erlotinib in Advanced Biliary Tract Cancer

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    AbstractBACKGROUND: We previously reported that the addition of erlotinib to gemcitabine and oxaliplatin (GEMOX) resulted in greater antitumor activity and might be a treatment option for patients with biliary tract cancers (BTCs). Molecular subgroup analysis of treatment outcomes in patients who had specimens available for analysis was undertaken. METHODS: Epidermal growth factor receptor (EGFR), KRAS, and PIK3CA mutations were evaluated using peptide nucleic acid–locked nucleic acid polymerase chain reaction clamp reactions. Survival and response rates (RRs) were analyzed according to the mutational status. Sixty-four patients (48.1%) were available for mutational analysis in the chemotherapy alone group and 61 (45.1%) in the chemotherapy plus erlotinib group. RESULTS: 1.6% (2/116) harbored an EGFR mutation (2 patients; exon 20), 9.6% (12/121) harbored a KRAS mutation (12 patients; exon 2), and 9.6% (12/118) harbored a PIK3CA mutation (10 patients, exon 9 and 2 patients, exon 20). The addition of erlotinib to GEMOX in patients with KRAS wild-type disease (n = 109) resulted in significant improvements in overall response compared with GEMOX alone (30.2% vs 12.5%, P = .024). In 95 patients with both wild-type KRAS and PIK3CA, there was evidence of a benefit associated with the addition of erlotinib to GEMOX with respect to RR as compared with GEMOX alone (P = .04). CONCLUSION: This study demonstrates that KRAS mutational status might be considered a predictive biomarker for the response to erlotinib in BTCs. Additionally, the mutation status of PIK3CA may be a determinant for adding erlotinib to chemotherapy in KRAS wild-type BTCs

    Enterobacter nimipressuralis as a cause of pseudobacteremia

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    <p>Abstract</p> <p>Background</p> <p>The clinical significance of the <it>Enterobacter nimipressuralis </it>as human pathogens remains unclear.</p> <p>Case presentations</p> <p>The microbiologic culture monitoring system of sterile body fluids revealed on an episode of <it>Enterobacter cloacae </it>and <it>Enterobacter amnigenus </it>in blood culture results on the same day; the antibiotic sensitivity and MIC were nearly the same for both species. First patient was a healthy woman with postmenopausal syndrome, while second patient with herpes zoster. Both patients had febrile sensations without signs of bacteremia. <it>E. amnigenus </it>was also cultured from the unused package of salined cotton in the container through epidemiologic investigation. The cultured <it>Enterobacter </it>species were all identified as <it>E. nimipressuralis </it>through <it>hsp60 </it>gene sequencing and infrequent-restriction-site PCR (IRS-PCR).</p> <p>Conclusion</p> <p>When an unusual microorganisms such as <it>E. nimipressuralis </it>is isolated from blood of a patient with no clinical signs of sepsis, a pseudobacteremia should be suspected. When the antibiogram and MIC test results of bacterial cultures from two or more patients are nearly the same, although the species involved may appear different, it may be necessary to prove that they are the same species through molecular methods. The microbiologic cultures monitoring system will probably help to detect pseudobacteremia and other pseudo infections through reliable and fast identification.</p

    The role of nafamostat mesilate as a regional anticoagulant during extracorporeal membrane oxygenation

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    Background Anticoagulation during extracorporeal membrane oxygenation (ECMO) usually is required to prevent thrombosis. The aim of this study was to investigate the usefulness of nafamostat mesilate (NM) as a regional anticoagulant during veno-arterial ECMO (VA-ECMO) treatment. Methods We retrospectively reviewed the medical records of 16 patients receiving VA-ECMO and NM from January 2017 to June 2020 at Haeundae Paik Hospital. We compared clinical and laboratory data, including activated partial thromboplastin time (aPTT), which was measured simultaneously in patients and the ECMO site, to estimate the efficacy of regional anticoagulation. Results The median patient age was 68.5 years, and 56.3% of patients were men. Cardiovascular disease was the most common primary disease (75.0%) requiring ECMO treatment, followed by respiratory disease (12.5%). The median duration of ECMO treatment was 7.5 days. Among 16 patients, seven were switched to NM after first using heparin as an anticoagulation agent, and nine received only NM. When comparing aPTT values in the NM group between patients and the ECMO site, that in patients was significantly lower than that at the ECMO site (73.57 vs. 79.25 seconds; P=0.010); in contrast, no difference was observed in the heparin group. Conclusions NM showed efficacy as a regional anticoagulation method by sustaining a lower aPTT value compared to that measured at the ECMO site. NM should be considered as a safer regional anticoagulation method in VA-ECMO for patients at high risk of bleeding
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