59 research outputs found
Surface plasmon resonance tuning of Ag nanoisland films using a CO₂ laser
We demonstrate that the surface plasmon resonance of Ag nanoislands (NIs) can be conveniently tuned through the laser power and irradiation time. For instance, the resonance wavelength of Ag NIs can be tuned from 548 nm to 452 nm under the 3 W laser power simply by varying the irradiation time from 5 s to 2 min. Interestingly, the position-dependent optical absorption spectra and SEM analysis reveals that the Ag NIs gradually disappear from the irradiation center even at 3 W if the irradiation time is longer. This means that the macroscopic diffusion of Ag atoms on the substrate takes place during the CO₂ laser irradiation, and its driving force would be the temperature gradient along the radial direction with respect to the irradiation center due to the spatial beam profile of the laser
Acute CO2 tolerance limits of juveniles of three marine invertebrates, Sepia lycidas, Sepioteuthis lessoniana, and Marsupenaeus japonicus
CO2 ocean storage is proposed as a possible measure to mitigate climate changes caused by increasing atmospheric concentrations of the gas. The feasibility of the measure has been intensively investigated, yet its biological impact on marine animals is still largely unknown. We investigated the acute CO2 tolerance of juveniles of three marine invertebrates; the cuttlefish, Sepia lycidas, the squid, Sepioteuthis lessoniana, and the prawn, Marsupenaeus japonicus. Median tolerance limits of CO2 were 8.4% (24 h) for the cuttlefish, 5.9% (24 h) and 3.8% (48 h) for the squid and 14.3% (72 h) for the prawn. Comparison of these and previously reported data suggests an inverse relationship between O2 requirement and CO2 tolerance among marine animals
Revised Structure of Cercidinin A, a Novel Ellagitannin Having (R)-Hexahydroxydiphenoyl Esters at the 3, 4-Positions of Glucopyranose
The structue of cercidinin A, an ellagitannin isolated from the bark of Cercidiphyllum japonicum, was revised to 1, 2, 6-tri-O-galloyl-3, 4-(R)-hexahydroxydipenoyl-β-D-glucose by two-dimensional NMR spectral analysis. Cercidinin A represents the first ellagitannin possessing a hexahydroxydiphenoyl group at the 3, 4-positions of a modified 4C1-glucopyranose core
Two Distinct Mechanisms Underlying γδ T Cell-Mediated Regulation of Collagen Type I in Lung Fibroblasts
Idiopathic pulmonary fibrosis is a chronic intractable lung disease, leading to respiratory failure and death. Although anti-fibrotic agents delay disease progression, they are not considered curative treatments, and alternative modalities have attracted attention. We examined the effect of human γδ T cells on collagen type I in lung fibroblasts. Collagen type I was markedly reduced in a γδ T cell number-dependent manner following treatment with γδ T cells expanded with tetrakis-pivaloxymethyl 2-(thiazole-2-ylamino) ethylidene-1,1-bisphosphonate (PTA) and interleukin-2. Collagen type I levels remained unchanged on addition of γδ T cells to the culture system through a trans-well culture membrane, suggesting that cell–cell contact is essential for reducing its levels in lung fibroblasts. Re-stimulating γδ T cells with (E)-4-hydroxy-3-methylbut-2-enyl diphosphate (HMBPP) reduced collagen type I levels without cell–cell contact, indicating the existence of HMBPP-induced soluble anti-fibrotic factors in γδ T cells. Adding anti-interferon-γ (IFN-γ)-neutralizing mAb restored collagen type I levels, demonstrating that human γδ T cell-derived IFN-γ reduces collagen type I levels. Conversely, interleukin-18 augmented γδ T cell-induced suppression of collagen type I. Therefore, human γδ T cells reduce collagen levels in lung fibroblasts via two distinct mechanisms; adoptive γδ T cell transfer is potentially a new therapeutic candidate
Stability and Metastability of Li3YCl6 and Li3HoCl6
[EN] Metastable solid electrolytes exhibit superior conductivity compared to stable ones, making them a subject of considerable interest. However, synthesis of the metastable phase is affected by multiple thermodynamic and kinetic parameters, leading to ambiguity in the organization of stability and metastability. In this study, we organized remnant and intermediate metastability based on temperature. The intermediate metastable phase, which is less stable than the temperature-independent stable phase, typically transforms into the stable phase(s) at high temperatures. In contrast, the remnant metastable phase is formed by first obtaining most stable phase at specific temperatures and then “trapping” it by rapidly changing the temperature. By investigating Li+ conducting chlorides, Li3MCl6 (M = Y and Ho), we demonstrated that heating starting materials to approximately 600 K produced low-temperature Li3MCl6 phase with one formula unit while further heating resulted in high-temperature Li3MCl6 phase with three formula units. Annealing quenched Li3MCl6 at 573 K resulted in a phase transition from the high-temperature to low-temperature phase, indicating that the high-temperature phase was remnant metastable at low temperatures.This research was partially supported by KAKENHI (Grant No. JP20KK0124), JST PRESTO (Grant Nos. JPMJPR21Q2 and JPMJPR21Q8), and Grant-in-Aid for JSPS Fellows (21J11152).N
A comparative study of the sarcopenia screening in older patients with interstitial lung disease
Background: The Asian Working Group for Sarcopenia 2019 (AWGS 2019) is the gold standard diagnostic criteria for sarcopenia in Asian populations. The calf circumference (CalF), the strength, assistance in walking, rising from a chair, climbing stairs, and falls (SARC-F) and the SARC-CalF questionnaires for sarcopenia screening have been used by AWGS 2019. The aim of this study was to assess accuracy of these three sarcopenia screening tools in patients with interstitial lung disease.Methods: In this cross-sectional study, stable patients with interstitial lung disease were enrolled. The SARC-F, SARC-CalF, and CalF, used in patients with interstitial lung disease, were compared to the diagnostic criteria proposed by AWGS 2019. The accuracy of screening tools was compared using sensitivity and specificity. Moreover, areas under the receiver operating characteristic curves (AUC) were computed.Results: Seventy eight patients were analyzed, and sarcopenia was identified in 25 (32.1%) patients with interstitial lung disease by the AWGS 2019 criteria. The sensitivity of the CalF was highest (96%) of the three screening tools, while the specificity was 60%. The sensitivity of SARC-F and SARC-CalF were 24% and 68%, while the specificity were 92% and 66%, respectively. The AUCs of CalF, SARC-F, and SARC-CalF in all patients were 0.78, 0.58, and 0.67, respectively.Conclusions: The CalF is most suitable for screening sarcopenia in patients with interstitial lung disease, while SARC-F and SARC-CalF are not
Antiproliferative Constituents in the Plant 8. Seeds of Rhynchosia volubilis
The MeOH extract of the seeds of Rhynchosia volubilis (Leguminosae) showed antiproliferative activity against human gastric adenocarcinoma [MK-1, 50% growth inhibition (GI50): 25 μg/ml], human uterus carcinoma (HeLa, GI50: 30 μg/ml), and murine melanoma (B16F10, GI50: 8 μg/ml) cells. Bioactivity-guided fractionation resulted in the isolation of gallic acid methylester (1), gallic acid (2), 7-O-galloylcatechin (3), 1,6-di-O-galloylglucose (4), 1-O-galloylglucose (5), and trigalloylgallic acid (6), and their antiproliferative activity was estimated. All showed much stronger inhibition against B16F10 cell growth than against HeLa and MK-1 cell growth. Compound 2 and its tetramer (6) with a free carboxyl group showed higher activity than those which did not have a free carboxyl group. In relation to the gallic acid tetramer (6), two gallic acid dimers (ellagic acid and dehydrodigallic acid) and trimers (tergallic acid dilactone and flavogallonic acid dilactone) were tested for their activity, and compared with those of the isolates
Triterpene hexahydroxydiphenoyl esters and a quinic acid purpurogallin carbonyl ester from the leaves of Castanopsis fissa.
Triterpene hexahydroxydiphenoyl (HHDP) esters have only been isolated from Castanopsis species, and the distribution of these esters in nature is of chemotaxonomical interest. In this study, the chemical constituents of the leaves of Castanopsis fissa were examined in detail to identify and isolate potential HHDP esters. Together with 53 known compounds, 3,4-di-O-galloyl-1-O-purpurogallin carbonyl quinic acid (1) and 3,24-(S)-HHDP-2α,3β,23,24-tetrahydroxytaraxastan-28,20β-olide (2) were isolated and their structures were elucidated by spectroscopic and chemical methods. The polyphenols of the leaves were mainly composed of galloyl quinic acids, triterpenes HHDP esters, ellagitannins and flavonol glycosides. In particular, the isolation yields of 1,3,4-trigalloyl quinic acid and compound 2 were 1.53% and 0.27%, respectively, from the fresh leaves. The presence of lipid soluble HHDP esters of oleanane-type triterpenes as one of the major metabolites is an important chemotaxonomical discovery. Lipase inhibition activities and ORAC values of the major constituents were compared. The triterpene HHDP ester showed moderate lipase inhibition activity and myricitrin gave the largest ORAC value
Wide polarized potential windows at the interface between water and an ionic liquid, tetraheptylammonium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate
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