13,581 research outputs found
Alpha-tocopherol exerts protective function against the mucotoxicity of particulate matter in amphibian and human goblet cells
Exposure to particulate matter (PM) in ambient air is known to increase the risk of cardiovascular disorders and mortality. The cytotoxicity of PM is mainly due to the abnormal increase of reactive oxygen species (ROS), which damage cellular components such as DNA, RNA, and proteins. The correlation between PM exposure and human disorders, including mortality, is based on long-term exposure. In this study we have investigated acute responses of mucus-secreting goblet cells upon exposure to PM derived from a heavy diesel engine. To this end, we employed the mucociliary epithelium of amphibian embryos and human Calu-3 cells to examine PM mucotoxicity. Our data suggest that acute exposure to PM significantly impairs mucus secretion and results in the accumulation of mucus vesicles in the cytoplasm of goblet cells. RNA-seq analysis revealed that acute responses to PM exposure significantly altered gene expression patterns; however, known regulators of mucus production and the secretory pathway were not significantly altered. Interestingly, pretreatment with alpha-tocopherol nearly recovered the hyposecretion of mucus from both amphibian and human goblet cells. We believe this study demonstrates the mucotoxicity of PM and the protective function of alpha-tocopherol on mucotoxicity caused by acute PM exposure from heavy diesel engines
Raf kinase inhibitor protein1 is a myogenic inhibitor with conserved function in avians and mammals
Ductographic Findings of Breast Cancer
Ductography has become the gold standard for the evaluation of patients exhibiting pathologic nipple discharges. In nine patients (age range, 29-67 years; median age, 51 years) with invasive (n=5) or intraductal (n=4) cancer, ductographic findings were recorded, then correlated with mammographic and sonographic findings. Common ductographic findings included complete ductal obstruction, multiple irregular filling defects in the nondilated peripheral ducts, ductal wall irregularities, periductal contrast extravasation, and ductal displacement. Faint microcalcifications or ill-defined masses, which were not opacified by contrast material, were often discovered adjacent to ductal abnormalities. Mammographically and sonographically occult diffusely spreading intraductal cancers often manifested as pathologic nipple discharge. In such cases, meticulous ductographic examinations and interpretations were crucial in order not to miss breast cancers
A transformative route to nanoporous manganese oxides of controlled oxidation states with identical textural properties
Nanoporous nanocrystalline metal oxides with tunable oxidation states are crucial for controlling their catalytic, electronic, and optical properties. However, previous approaches to modulate oxidation states in nanoporous metal oxides commonly lead to the breakdown of the nanoporous structure as well as involve concomitant changes in their morphology, pore size, surface area, and nanocrystalline size. Herein, we present a transformative route to nanoporous metal oxides with various oxidation states using manganese oxides as model systems. Thermal conversion of Mn-based metal-organic frameworks (Mn-MOFs) at controlled temperature and atmosphere yielded a series of nanoporous manganese oxides with continuously tuned oxidation states: MnO, Mn3O 4, Mn5O8, and Mn2O3. This transformation enabled the preparation of low-oxidation phase MnO and metastable intermediate phase Mn5O8 with nanoporous architectures, which were previously rarely accessible. Significantly, nanoporous MnO, Mn3O4, and Mn5O8 had a very similar morphology, surface area, and crystalline size. We investigated the electrocatalytic activity of nanoporous manganese oxides for oxygen reduction reaction (ORR) to identify the role of oxidation states, and observed oxidation state-dependent activity and kinetics for the ORR.close5
Recurrent True Brachial Artery Aneurysm
True aneurysm of the brachial artery is a rare disease entity. The mechanism of aneurysm formation is considered to be compression of the arterial wall, producing contusion of the media and subsequent weakness of the wall and fusiform dilatation. It can be caused by arteriosclerotic, congenital, and metabolic disorders, and can be associated with diseases such as Kawasaki's disease. Doppler ultrasonography, computed tomography, arteriography, and selective upper extremity angiography may be performed for establishing the diagnosis of aneurysm. The best therapeutic option is operative repair, and it should be performed without any delay, in order to prevent upper extremity ischemic or thrombotic sequelae. Here, we report a case of recurrent brachial artery aneurysm with review of the literature
Electrochemical Properties of Polyaniline-Coated Li-Rich Nickel Manganese Oxide and Role of Polyaniline Coating Layer
Polyaniline is coated on Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 synthesized via co-precipitation. X-ray diffraction patterns exhibit that the polyaniline coating does not affect structural change of the Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 , and the resulting transmission electron microscopic images show the presence of coating layers on the surface of Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 . Electrochemical tests using coin type cells confirm that the surface modification by polyaniline is effective in maintaining capacity and retention upon cycling. The conducting coating character also assists improvement in rate capability. The polyaniline layer forms F-doped polyaniline during cycling, as is proved by time-of-flight secondary ion mass spectroscopy. Therefore, the presence of the polyaniline layers plays a role in lowering HF levels via scavenging F โ from HF in the electrolyte, and this F-doped polyaniline layer also assists in protecting the Li [Li 0.2 Efforts have been made to improve their intrinsic low rate capability stemming from the tetravalent Mn in the oxide matrix and cyclability as well. Hence, partial substitutions of Mn site with other elements or surface modifications have been made. 10,12 A recent report by Kang et al. 14 suggested that surface modification by Al(OH) 3 on Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 was fairly effective in capacity retention, rate capability, and thermal stability. Similar effects were also reported using Al 2 O 3 coating and AlPO 4 coating on the over-lithiated manganese oxides. 17,18 Furthermore, we perceive the main problem of oxide coating to be difficulty in complete encapsulation of active materials like core-shell materials due to condensation and crystal growth of the coating materials even at mild heat-treatment condition; it, hence, shows an islands-like coating. 18 For the reason, we object to complete encapsulation of Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 using a conductive polyaniline, which does not need further heat-treatment after polymerization. Also, the conductive coating layers are expected to improve the rate capability of the active material. In this paper, we introduce the details of polyaniline-coated Li [ โข C for 5 h. The dehydrates were thoroughly mixed with an appropriate amount of LiOH (samchun) and calcined at 900 โข C for 15 h in air. In attempt to modify the as-synthesized active materials with polyaniline (hereafter referred as to be PANi), Cl โ -doped emeraldine salt state PANi ([C 24 H 26 N 4 (Cl) 2 ] n ) was polymerized with aniline monomer (C 6 H 5 NH 2 ) and ammonium persulfate ((NH 4 ) 2 S 2 O 8 ,). First, aniline monomer and ammonium persulfate were separately poured into 1M HCl aqueous solution, and they were mixed to self-polymerize for 2 days. And the produced PANi in the solution was rinsed with absolute ethanol and acetone to remove the residual monomer, oligomer, and low molecular weight organic intermediates. To prepare violet pernigraniline base state (hereafter referred as to be VPB) PANi which needs to be dissolved in N-methyl-2-pyrrolinon(NMP) or m-cresol and so on, 19,20 the Cl โ -doped PANi was poured into a 1M NaOH aqueous solution and continuously stirred at 350 rpm for 2 days. Then, the solution was dried at 80 โข C in air. The obtained VPB powders were mixed with campor-10-sulfonic acid, ฮฒ (CSA, Sigma-aldrich, with a ratio of 4:1 in weight) to prepare (SO) 3 2โ -doped emeraldine salt state (hereafter referred as to be ES) PANi and dissolved into N-methyl-2-pyrrolinon (NMP X-ray diffractometry (XRD, Rint-2000, Rigaku) and highresolution transmission electron microscopy (HR-TEM, JEM-3010, JEOL) were employed to characterize the synthesized powders. Timeof-flight secondary ion mass spectroscopy (ToF-SIMS, PHI TRIFT V nanoTOF, ULVAC-PHI) was also used to confirm the presence of th
Three newly recorded plants of South Korea: Muhlenbergia ramosa (Hack. ex Matsum.) Makino, Dichanthelium acuminatum (Sw.) Gould & C.A. Clark and Rottboellia cochinchinensis (Lour.) Clayton
AbstractThree new Poaceae species are reported in South Korea. Muhlenbergia ramosa was found in Boryeong-si, Iksan-si, Jangsu-gun and Gwangju. Dichanthelium acuminatum and Rottboellia cochinchinensis were found in Jeonju-si, Jeollabuk-do and Seogwipo-si, Jeju-do which were thought to be alien species. Genus Dichanthelium and Rottboellia are newly reported in South Korea. Muhlenbergia ramosa was thought to be native to Korea
Role of Amphipathic Helix of a Herpesviral Protein in Membrane Deformation and T Cell Receptor Downregulation
Lipid rafts are membrane microdomains that function as platforms for signal transduction and membrane trafficking. Tyrosine kinase interacting protein (Tip) of T lymphotropic Herpesvirus saimiri (HVS) is targeted to lipid rafts in T cells and downregulates TCR and CD4 surface expression. Here, we report that the membrane-proximal amphipathic helix preceding Tip's transmembrane (TM) domain mediates lipid raft localization and membrane deformation. In turn, this motif directs Tip's lysosomal trafficking and selective TCR downregulation. The amphipathic helix binds to the negatively charged lipids and induces liposome tubulation, the TM domain mediates oligomerization, and cooperation of the membrane-proximal helix with the TM domain is sufficient for localization to lipid rafts and lysosomal compartments, especially the mutivesicular bodies. These findings suggest that the membrane-proximal amphipathic helix and TM domain provide HVS Tip with the unique ability to deform the cellular membranes in lipid rafts and to downregulate TCRs potentially through MVB formation
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