768 research outputs found
Development of a Procedure to Identify Aggregates for Bituminous Surfaces in Indiana
Adequate friction resistance is needed to prevent pavement slipperiness allowing vehicles to stop in a reasonable distance. For stone mastic asphalt surfaces, friction resistance is mainly a function of the interaction between the aggregates exposed at the road surface and vehicle tires. Aggregate performance is reduced with time by wear and polishing as a consequence of vehicular traffic. In this research a method to investigate performance based on physical, chemical and petrographic factors has been evaluated. The objective was to develop a laboratory method to test Indiana dolomite, limestone, sandstone, and gravel aggregates to predict friction resistance in the field and determine causes for the range of values among these aggregates. Assessment of gravel sources was based on individual rock types and their proportions comprising the gravel. Initial friction Values (IFV) and Polished Values (PV) were determined in the laboratory with the British Wheel and Pendulum test and field values obtained from the towed friction trailer. For two laboratories involved a significant difference in IFV and PV was obtained so that further verification is required. Correlations between parameters were established which provide predictions of friction resistance based on laboratory specimens. A database of physical and chemical properties should be collected on aggregates used or considered for bituminous wearing courses. This includes the testing required for Class A aggregates plus elemental Mg and elemental Ca content
A Case of Successful Surgical Treatment of Migraine Headaches in a Patient with Sporadic Pulmonary Arteriovenous Malformations
Pulmonary arteriovenous malformations (PAVMs) are thin-walled aneurysms caused by abnormal communication between the pulmonary arteries and veins. Migraine headaches are sometimes the presenting clinical manifestation of PAVMs. Although embolotherapy, using detachable balloons or stainless steel coils, is generally accepted as the best choice for the treatment of multiple PAVMs, the mode of intervention for solitary PAVMs remains a subject of debate. We present a 43-yr-old woman with a 10-yr history of chronic migraines and dyspnea on exertion. She was discovered to have a large solitary centrally located PAVM, placing her at high risk of complications if she were to undergo percutaneous transcatheter embolization. She underwent successful surgical resection of her right middle lobe without complications, resulting in subsequent symptomatic improvement
Differential effects of Radix Paeoniae Rubra (Chishao) on cytokine and chemokine expression inducible by mycobacteria
<p>Abstract</p> <p>Background</p> <p>Upon initial infection with mycobacteria, macrophages secrete multiple cytokines and chemokines, including interleukin-6 (IL-6), IL-8 and tumor necrosis factor-α (TNF-α), to mediate host immune responses against the pathogen. Mycobacteria also induce the production of IL-10 <it>via </it>PKR activation in primary human monocytes and macrophages. As an anti-inflammatory cytokine, over-expression of IL-10 may contribute to mycobacterial evasion of the host immunity. <it>Radix Paeoniae Rubra </it>(RPR, <it>Chishao</it>), a Chinese medicinal herb with potentials of anti-inflammatory, hepatoprotective and neuroprotective effects, is used to treat tuberculosis. This study investigates the immunoregulatory effects of RPR on primary human blood macrophages (PBMac) during mycobacterial infection.</p> <p>Methods</p> <p>The interaction of Bacillus Calmette-Guerin (BCG) with PBMac was used as an experimental model. A series of procedures involving solvent extraction and fractionation were used to isolate bioactive constituents in RPR. RPR-EA-S1, a fraction with potent immunoregulatory effects was obtained with a bioactivity guided fractionation scheme. PBMac were treated with crude RPR extracts or RPR-EA-S1 before BCG stimulation. The expression levels of IL-6, IL-8, IL-10 and TNF-α were measured by qPCR and ELISA. Western blotting was used to determine the effects of RPR-EA-S1 on signaling kinases and transcriptional factors in the BCG-activated PBMac.</p> <p>Results</p> <p>In BCG-stimulated macrophages, crude RPR extracts and fraction RPR-EA-S1 specifically inhibited IL-10 production while enhanced IL-8 expression at both mRNA and protein levels without affecting the expressions of IL-6 and TNF-α. Inhibition of BCG-induced IL-10 expression by RPR-EA-S1 occurred in a dose- and time-dependent manner. RPR-EA-S1 did not affect the phosphorylation of cellular protein kinases including MAPK, Akt and GSK3β. Instead, it suppressed the degradation of IκBα in the cytoplasm and inhibited the translocation of transcription factor NF-κB1 p50 to the nucleus.</p> <p>Conclusion</p> <p>RPR crude extracts and its fraction RPR-EA-S1 inhibited anti-inflammatory cytokine IL-10 and enhanced pro-inflammatory chemokine IL-8 expression in BCG-activated PBMac. The inhibitory effects of RPR-EA-S1 on IL-10 expression in BCG-activated PBMac may be due to the reduced nuclear translocation of NF-κB1 p50.</p
Ultrafine particulate pollutants induce oxidative stress and mitochondrial damage.
The objectives of this study were to determine whether differences in the size and composition of coarse (2.5-10 micro m), fine (< 2.5 microm), and ultrafine (< 0.1 microm) particulate matter (PM) are related to their uptake in macrophages and epithelial cells and their ability to induce oxidative stress. The premise for this study is the increasing awareness that various PM components induce pulmonary inflammation through the generation of oxidative stress. Coarse, fine, and ultrafine particles (UFPs) were collected by ambient particle concentrators in the Los Angeles basin in California and used to study their chemical composition in parallel with assays for generation of reactive oxygen species (ROS) and ability to induce oxidative stress in macrophages and epithelial cells. UFPs were most potent toward inducing cellular heme oxygenase-1 (HO-1) expression and depleting intracellular glutathione. HO-1 expression, a sensitive marker for oxidative stress, is directly correlated with the high organic carbon and polycyclic aromatic hydrocarbon (PAH) content of UFPs. The dithiothreitol (DTT) assay, a quantitative measure of in vitro ROS formation, was correlated with PAH content and HO-1 expression. UFPs also had the highest ROS activity in the DTT assay. Because the small size of UFPs allows better tissue penetration, we used electron microscopy to study subcellular localization. UFPs and, to a lesser extent, fine particles, localize in mitochondria, where they induce major structural damage. This may contribute to oxidative stress. Our studies demonstrate that the increased biological potency of UFPs is related to the content of redox cycling organic chemicals and their ability to damage mitochondria
Exo70-Mediated Recruitment of Nucleoporin Nup62 at the Leading Edge of Migrating Cells is Required for Cell Migration
Nucleoporin Nup62 localizes at the central channel of the nuclear pore complex and is essential for nucleocytoplasmic transport. Through its FG-repeat domain, Nup62 regulates nuclear pore permeability and binds nuclear transport receptors. Here, we report that Nup62 interacts directly with Exo70 and colocalizes with Exo70 at the leading edge of migrating cells. Nup62 binds the N-terminal domain of Exo70 through its coiled-coil domain but not through its FG-repeat domain. Selective inhibition of leading edge Nup62 using RNA interference significantly reduces cell migration. Furthermore, Exo70 recruits Nup62 at the plasma membrane and at filopodia. Removal of the Exo70-binding domain of Nup62 prevents leading edge localization of Nup62. Analogous to Exo70, Nup62 cycles between the plasma membrane and the perinuclear recycling compartment. Altogether, we propose that Nup62 not solely regulates access to the cell nucleus, but additionally functions in conjunction with Exo70, a key regulator of exocytosis and actin dynamics, at the leading edge of migrating cells
Discovery and Genetic Characterization of Novel Paramyxoviruses Related to the Genus Henipavirus in Crocidura Species in the Republic of Korea
Paramyxoviruses, negative-sense single-stranded RNA viruses, pose a critical threat to
human public health. Currently, 78 species, 17 genera, and 4 subfamilies of paramyxoviruses are harbored by multiple natural reservoirs, including rodents, bats, birds, reptiles, and fish. Henipaviruses
are critical zoonotic pathogens that cause severe acute respiratory distress and neurological diseases
in humans. Using reverse transcription-polymerase chain reaction, 115 Crocidura species individuals
were examined for the prevalence of paramyxovirus infections. Paramyxovirus RNA was observed in
26 (22.6%) shrews collected at five trapping sites, Republic of Korea. Herein, we report two genetically
distinct novel paramyxoviruses (genus: Henipavirus): Gamak virus (GAKV) and Daeryong virus
(DARV) isolated from C. lasiura and C. shantungensis, respectively. Two GAKVs and one DARV were
nearly completely sequenced using next-generation sequencing. GAKV and DARV contain six genes
(30
-N-P-M-F-G-L-50
) with genome sizes of 18,460 nucleotides and 19,471 nucleotides, respectively.
The phylogenetic inference demonstrated that GAKV and DARV form independent genetic lineages
of Henipavirus in Crocidura species. GAKV-infected human lung epithelial cells elicited the induction
of type I/III interferons, interferon-stimulated genes, and proinflammatory cytokines. In conclusion,
this study contributes further understandings of the molecular prevalence, genetic characteristics
and diversity, and zoonotic potential of novel paramyxoviruses in shrews
Modification of the association between recreational physical activity and survival after breast cancer by promoter methylation in breast cancer-related genes
Background: Mechanisms underlying the inverse association between physical activity and survival after breast cancer are unresolved, but DNA methylation may play a role. We hypothesized that promoter methylation of breast cancer-related genes, as well as global methylation, may modify the association between prediagnostic recreational physical activity (RPA) and breast cancer mortality.
Methods: Using a population-based sample of 1254 women diagnosed with first primary breast cancer, we examined modification of the RPA-mortality association by gene-specific promoter methylation and global methylation. Average lifetime RPA was assessed from menarche to diagnosis through structured in-home interviews. Promoter methylation of 13 breast cancer-related genes was evaluated in archived tumor by methylation-specific polymerase chain reaction and MethyLight assay. Global methylation in white blood cell DNA was determined at long interspersed nucleotide element 1 and by the luminometric methylation assay. After approximately 15Â years of follow-up, 486 patients had died, and 186 of the deaths were breast cancer-related. We used Cox proportional hazards regression to estimate HRs and 95% CIs as well as likelihood ratio tests to assess multiplicative interactions.
Results: All-cause mortality was lower only among physically active women with methylated promoter of APC (HR 0.60, 95% CI 0.40–0.80), CCND2 (HR 0.56, 95% CI 0.32–0.99), HIN (HR 0.55, 95% CI 0.38–0.80), and TWIST1 (HR 0.28, 95% CI 0.14–0.56) in tumors, but not among those with unmethylated tumors (significant interaction p < 0.05). We found no interaction between RPA and global methylation.
Conclusions: The improved survival after breast cancer that is associated with RPA may be more pronounced in women with promoter tumor methylation in biologically plausible genes
Kinetic Turbulence
The weak collisionality typical of turbulence in many diffuse astrophysical
plasmas invalidates an MHD description of the turbulent dynamics, motivating
the development of a more comprehensive theory of kinetic turbulence. In
particular, a kinetic approach is essential for the investigation of the
physical mechanisms responsible for the dissipation of astrophysical turbulence
and the resulting heating of the plasma. This chapter reviews the limitations
of MHD turbulence theory and explains how kinetic considerations may be
incorporated to obtain a kinetic theory for astrophysical plasma turbulence.
Key questions about the nature of kinetic turbulence that drive current
research efforts are identified. A comprehensive model of the kinetic turbulent
cascade is presented, with a detailed discussion of each component of the model
and a review of supporting and conflicting theoretical, numerical, and
observational evidence.Comment: 31 pages, 3 figures, 99 references, Chapter 6 in A. Lazarian et al.
(eds.), Magnetic Fields in Diffuse Media, Astrophysics and Space Science
Library 407, Springer-Verlag Berlin Heidelberg (2015
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