24 research outputs found
Ultraviolet photodepletion spectroscopy of dibenzo-18-crown-6-ether complexes with alkali metal cations
Ultraviolet photodepletion spectra of dibenzo-18-crown-6-ether complexes with alkali metal cations (M+-DB18C6, M = Cs, Rb, K, Na, and Li) were obtained in the gas phase using electrospray ionization quadrupole ion-trap reflectron time-of-flight mass spectrometry. The spectra exhibited a few distinct absorption bands in the wavenumber region of 35450ā37800 cm^(ā1). The lowest-energy band was tentatively assigned to be the origin of the S_0-S_1 transition, and the second band to a vibronic transition arising from the ābenzene breathingā mode in conjunction with symmetric or asymmetric stretching vibration of the bonds between the metal cation and the oxygen atoms in DB18C6. The red shifts of the origin bands were observed in the spectra as the size of the metal cation in M^+-DB18C6 increased from Li^+ to Cs^+. We suggested that these red shifts arose mainly from the decrease in the binding energies of larger-sized metal cations to DB18C6 at the electronic ground state. These size effects of the metal cations on the geometric and electronic structures, and the binding properties of the complexes at the S_0 and S_1 states were further elucidated by theoretical calculations using density functional and time-dependent density functional theories
High frequencies of Y-chromosome haplogroup O2b-SRY465 lineages in Korea: a genetic perspective on the peopling of Korea
<p>Abstract</p> <p>Background</p> <p>Koreans are generally considered a Northeast Asian group, thought to be related to Altaic-language-speaking populations. However, recent findings have indicated that the peopling of Korea might have been more complex, involving dual origins from both southern and northern parts of East Asia. To understand the male lineage history of Korea, more data from informative genetic markers from Korea and its surrounding regions are necessary. In this study, 25 Y-chromosome single nucleotide polymorphism markers and 17 Y-chromosome short tandem repeat (Y-STR) loci were genotyped in 1,108 males from several populations in East Asia.</p> <p>Results</p> <p>In general, we found East Asian populations to be characterized by male haplogroup homogeneity, showing major Y-chromosomal expansions of haplogroup O-M175 lineages. Interestingly, a high frequency (31.4%) of haplogroup O2b-SRY465 (and its sublineage) is characteristic of male Koreans, whereas the haplogroup distribution elsewhere in East Asian populations is patchy. The ages of the haplogroup O2b-SRY465 lineages (~9,900 years) and the pattern of variation within the lineages suggested an ancient origin in a nearby part of northeastern Asia, followed by an expansion in the vicinity of the Korean Peninsula. In addition, the coalescence time (~4,400 years) for the age of haplogroup O2b1-47z, and its Y-STR diversity, suggest that this lineage probably originated in Korea. Further studies with sufficiently large sample sizes to cover the vast East Asian region and using genomewide genotyping should provide further insights.</p> <p>Conclusions</p> <p>These findings are consistent with linguistic, archaeological and historical evidence, which suggest that the direct ancestors of Koreans were proto-Koreans who inhabited the northeastern region of China and the Korean Peninsula during the Neolithic (8,000-1,000 BC) and Bronze (1,500-400 BC) Ages.</p
Association of Plasma Retinol-Binding Protein 4, Adiponectin, and High Molecular Weight Adiponectin with Insulin Resistance in Non-Diabetic Hypertensive Patients
āThe authors have no financial conflicts of interest. Purpose: The aim of this study was to determine whether retinol-binding protein 4 (RBP4), adiponectin and high molecular weight (HMW) adiponectin are associated with insulin resistance (IR) and metabolic parameters in non-diabetic hypertensive patients. Also, we sought to compare the predictive values of these adipocytokines for IR in non-diabetic hypertensive patients. Materials and Methods: Analyses of RBP4, adiponectin, and HMW adiponectin were performed on 308 non-diabetic hypertensives (148 males, age 58 Ā± 10 years, 189 non-metabolic syndrome and 119 metabolic syndrome). The homeostasis model assessment (HOMA) index for IR, lipid profiles, and anthropometric measure-ments were assessed. Results: There was no significant difference in RBP4 levels according to the presence of metabolic syndrome, although adiponectin and HMW adiponectin were significantly lower in metabolic syndrome. Correlation analysis of log RBP4 with IR and metabolic indices revealed that there was no significant correlation of RBP4 with wais
Quercetin, the active phenolic component in kiwifruit, prevents hydrogen peroxide-induced inhibition of gap-junction intercellular communication
We evaluated the effects of the two main kiwifruit cultivars (gold kiwifruit (GOK) and green kiwifruit (GRK)) and their active phenolic compound, quercetin, on H2O2-induced inhibition of gap-junction intercellular communication (GJIC) in WB-F344 rat liver epithelial cells. We found that both GOK and GRK protect WB-F344 cells from H2O2-induced inhibition of GJIC. The extracellular signal-regulated protein kinase 1/2 (ERK1/2)-connexin 43 (Cx43) signalling pathway is crucial for the regulation of GJIC, and both GOK and GRK blocked the H2O2-induced phosphorylation of Cx43 and ERK1/2 in WB-F344 cells. Quercetin alone attenuated the H2O2-mediated ERK1/2-Cx43 signalling pathway and consequently reversed H2O2-mediated inhibition of GJIC in WB-F344 cells. A free radical-scavenging assay using 1,1-diphenyl-2-picrylhydrazyl showed that the scavenging activity of quercetin was higher than that of a synthetic antioxidant, butylated hydroxytoluene, per mol, suggesting that the chemopreventive effect of quercetin on H2O2-mediated inhibition of ERK1/2-Cx43 signalling and GJIC may be mediated through its free radical-scavenging activity. Since the carcinogenicity of reactive oxygen species such as H2O2 is attributable to the inhibition of GJIC, GOK, GRK and quercetin may have chemopreventive potential by preventing the inhibition of GJI
Giant Mesenteric Lipoma As an Unusual Cause of Abdominal Pain: A Case Report and a Review of the Literature
We report a rare case of giant mesenteric lipoma presenting with colicky abdominal pain. A 29-yr-old woman underwent laparoscopic resection for a giant mesenteric lipoma causing compression of the ileal loop. The resected ileal segment was encased by a giant fatty tissue, and normal mucosal fold patterns of the resected ileum were effaced by the mass. Microscopically, the mass was characterized by homogenous mature adipose tissue without cellular atypia, which was compatible with the diagnosis of a mesenteric lipoma. Despite the benign nature of this tumor, total excision with or without the affected intestinal loop should be considered if intestinal symptoms such as abdominal pain are present
A case of hemocholecyst associated with hemobilia following radiofrequency ablation therapy for hepatocellular carcinoma
Radiofrequency ablation (RFA) is performed as an alternative to surgical resection for primary or secondary liver malignancies. Although RFA can be performed safely in most patients, early and late complications related to mechanical or thermal damage occur in 8-9.5% cases. Hemocholecyst, which refers to hemorrhage of the gallbladder, has been reported with primary gallbladder disease or as a secondary event associated with hemobilia. Hemobilia, defined as hemorrhage in the biliary tract and most commonly associated with accidental or iatrogenic trauma, is a rare complication of RFA. Here we report a case of hemocholecyst associated with hemobilia after RFA for hepatocellular carcinoma that was successfully managed by laparoscopic cholecystectomy
Effect of Powder Heat Treatment on Chemical Composition and Thermoelectric Properties of Bismuth Antimony Telluride Alloys Fabricated by Combining Water Atomization and Spark Plasma Sintering
In this work, Bi0.5Sb1.5Te3 materials were produced by an economically viable and time efficient water atomization process. The powder samples were heat treated at different temperatures (673 K, 723 K, 743 K, 773 K, 803 K, and 823 K) followed by spark plasma sintering (SPS). It was found that the Te evaporated slightly at 723 K and 743 K and became dominated at 773 K, 803 K, and 823 K, which severely influences the thermoelectric properties. The electrical conductivity was significantly improved for over 803 K heat treated samples due to the remarkable improvement in hole concentration. The power factor values for the 803 K and 823 K samples were significantly larger at T > 350 K compared to other samples. Consequently, the peak ZT of 0.92 at 350 K was obtained for the 803 K sample, which could be useful in commercial thermoelectric power generation
Inhaled delivery of recombinant interferon-lambda restores allergic inflammation after development of asthma by controlling Th2-and Th17-cell-mediated immune responses
Remarkable progress has recently been achieved to identify the biological function and potential value of novel therapeutic targets for the effective control of allergic asthma. Interferon (IFN)-lambda has been suggested to restrict chronic inflammation in the lungs of asthmatic mice and we sought to determine the contribution of IFN-lambda as an asthma therapeutic. We show that inhaled IFN-lambda can restrict Th2 and Th17 inflammation in the lungs of asthmatic mice, accompanied with alteration of IL-10 secretion. BALB/C mice were used for an asthmatic mouse model with OVA. Recombinant IFN-lambda s (IFN-lambda(2): 2 mu g, IFN-lambda(3): 2 mu g) were inoculated into asthmatic mice after OVA challenge by intranasal delivery. Lungs of asthmatic mice were severely inflamed, with extensive inflammatory cell infiltration and increased goblet cell metaplasia with higher total lung resistance. Transcription of IL-4, IL-5, IL-13, and IL-17A was significantly higher until five days after the final OVA challenge. Asthmatic mice were administered recombinant IFN-lambda via inhalation three times after the last challenge and the asthmatic mice showed improvement in lung histopathologic findings, and total lung resistance was maintained under normal range. IFN-lambda inhalation exhibited significant decreases in Th2 and Th17 cytokine levels, and the populations of Th2 and Th17 cells were recovered from the lungs of asthmatic mice. Additionally, increase in IL-10 secretion from CD4 + Th cells population was observed in response to inhaled delivery of IFN-lambda along with alterations in Th2 and Th17 cell-derived inflammation. Our findings show that inhaled delivery of IFN-lambda can restrict airway inflammation in the lungs of asthmatic mice by controlling Th2-and Th17-mediated responses accompanied by regulation of IL-10 secretion even after asthma development.N
Investigation of the magnetic properties and fracture behavior of NdāFeāB alloy powders during high-energy ball milling
In this work, NdāFeāB alloy powders are fabricated via high energy ball milling and their fracture behavior and magnetic properties are investigated at different milling times. The powder characteristics (particle shape, size, size distribution, and microstructure) and magnetic properties of the NdāFeāB alloys are systematically analyzed. The initial spherical NdāFeāB powder is cracked/crushed even after a short period of milling (30 s) due to the high impact energy generated during high energy ball milling. These randomly cracked polygonal-shaped powders are fragmented after 5 min of milling and converted to fine powders. Interestingly, the fine particles after milling for 5 min are conducive to agglomeration at longer milling times (20ā60 min) and formed spherically-shaped agglomerated powder. Additionally, the sphericity of the powder increased to 92% by re-pulverization and agglomeration at 60 min. The milled powder shows the Nd _2 Fe _14 B phase, and the x-ray diffraction patterns exhibit peak broadening with increasing milling time, clearly confirming the powder refinement behavior by high energy ball milling. The magnetic properties of the milled powders are systematically investigated and their behavior is elucidated as a function of the milling time