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1.
Molecules ; 29(1)2023 Dec 27.
Article in English | MEDLINE | ID: mdl-38202741

ABSTRACT

Acute kidney injury (AKI) and chronic kidney disease (CKD) have become public health problems due to high morbidity and mortality. Currently, drugs recommended for patients with AKI or CKD are extremely limited, and candidates based on a new mechanism need to be explored. 84-B10 is a novel 3-phenylglutaric acid derivative that can activate the mitochondrial protease, Lon protease 1 (LONP1), and may protect against cisplatin-induced AKI and unilateral ureteral obstruction- or 5/6 nephrectomy [5/6Nx]-induced CKD model. Preclinical studies have shown that 84-B10 has a good therapeutic effect, low toxicity, and is a good prospect for further development. In the present study, the UHPLC-MS/MS method was first validated then applied to the pharmacokinetic study and tissue distribution of 84-B10 in rats. Physicochemical properties of 84-B10 were then acquired in silico. Based on these physicochemical and integral physiological parameters, a physiological based pharmacokinetic (PBPK) model was developed using the PK-Sim platform. The fitting accuracy was estimated with the obtained experimental data. Subsequently, the validated model was employed to predict the pharmacokinetic profiles in healthy and chronic kidney injury patients to evaluate potential clinical outcomes. Cmax in CKD patients was about 3250 ng/mL after a single dose of 84-B10 (0.41 mg/kg), and Cmax,ss was 1360 ng/mL after multiple doses. This study may serve in clinical dosage setting in the future.


Subject(s)
Acute Kidney Injury , Renal Insufficiency, Chronic , Humans , Animals , Rats , Tandem Mass Spectrometry , Acute Kidney Injury/drug therapy , Renal Insufficiency, Chronic/drug therapy , Cisplatin , Endopeptidases , Mitochondrial Proteins , ATP-Dependent Proteases
2.
Toxicol Mech Methods ; 33(5): 427-436, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36573377

ABSTRACT

In this work, a microfluidic lung chip with membrane supporting cell growth that can produce multiple concentration gradients of gas and liquid is introduced. The chip is composed of a gas gradient layer in the upper part, a porous membrane supporting cell growth in the middle and a liquid gradient layer in the lower part. The gas-liquid interface environment of the cells on the membrane can expose the cells to the gas in the upper layer and the liquid in the lower layer at the same time. Then, the chip is applied to the toxicity testing of formaldehyde in A549 cells. The results showed that at 6 × 10-5 mol/L formaldehyde, the survival rate of the cells in four channels were 90, 87, 81, and 71%, which shows a dose-response trend under the influence of different concentrations of formaldehyde. ROS staining results also showed that formaldehyde exposure at 6 × 10-5 mol/L lead to the increase of ROS level in the cells. These results suggest that the chip based on cell growth on membrane could be used for toxicological evaluation of environmental polluting gases.


Subject(s)
Formaldehyde , Lung , Microfluidics , Toxicity Tests , Formaldehyde/toxicity , Reactive Oxygen Species , Toxicity Tests/methods
3.
Acta Cardiol Sin ; 39(3): 449-456, 2023 May.
Article in English | MEDLINE | ID: mdl-37229330

ABSTRACT

Background: The superiority of the new-generation self-expanding Evolut R compared with the first-generation CoreValve with regards to outcomes after transcatheter aortic valve replacement (TAVR) is unclear. The aim of this study was to investigate the hemodynamic and clinical performance of Evolut R compared with its direct predecessor, CoreValve, in a Taiwanese population. Methods: This study included all consecutive patients who underwent TAVR with either CoreValve or Evolut R between March 2013 and December 2020. Thirty-day Valve Academic Research Consortium-2 (VARC-2)-defined outcomes and hemodynamic performances were investigated. Results: There were no significant differences in baseline demographic characteristics between the patients receiving CoreValve (n = 117) or Evolut R (n = 117). Aortic valve-in-valve procedures for failed surgical bioprosthesis and procedures under conscious sedation were performed significantly more often with Evolut R. Pre-dilatation was performed significantly more often and contrast media volume was significantly higher with CoreValve. Stroke (0% vs. 4.3%, p = 0.024) and the need for emergent conversion to open surgery (0% vs. 5.1%, p = 0.012) were significantly lower in Evolut R than in CoreValve recipients. Evolut R significantly reduced 30-day composite safety endpoint (4.3% vs. 15.4%, p = 0.004). Conclusions: Advancements in transcatheter valve technologies have resulted in improved outcomes for patients undergoing TAVR with self-expanding valves. With the new-generation Evolut R, device success was high and the 30-day composite safety endpoint was significantly reduced after TAVR compared with CoreValve.

4.
FASEB J ; 35(4): e21479, 2021 04.
Article in English | MEDLINE | ID: mdl-33710680

ABSTRACT

Triggering receptor expressed on myeloid cells 2 (TREM2) is a cell surface receptor expressed on macrophages, microglial cells, and pre-osteoclasts, and that participates in diverse cellular function, including inflammation, bone homeostasis, neurological development, and coagulation. In spite of the indispensable role of the TREM2 protein in the maintenance of immune homeostasis and osteoclast differentiation, the exact ligand for TREM2 has not yet been identified. Here, we report a putative TREM2 ligand which is secreted from MC38 cells and identified as a cyclophilin A (CypA). A specific interaction between CypA and TREM2 was shown at both protein and cellular levels. Exogenous CypA specifically interacted and co-localized with TREM2 in RAW264.7 cells, and the physical interactions were shown to regulate TREM2 signaling transduction. The Pro144 residue in the extracellular domain of TREM2 was found to be the specific binding site of CypA. When considered together, this provides evidence that CypA interacts specifically with TREM2 as a potent ligand.


Subject(s)
Cyclophilin A/metabolism , Ligands , Microglia/metabolism , Myeloid Cells/metabolism , Animals , Carrier Proteins/metabolism , Cells, Cultured , Humans , Macrophages/metabolism , Osteoclasts/metabolism
5.
Cell Biol Toxicol ; 38(4): 557-575, 2022 08.
Article in English | MEDLINE | ID: mdl-35267148

ABSTRACT

Human lung organoids (hLOs) are useful for disease modelling and drug screening. However, a lack of immune cells in hLOs limits the recapitulation of in vivo cellular physiology. Here, we generated hLOs containing alveolar macrophage (AMφ)-like cells derived from pluripotent stem cells (PSC). To bridge hLOs with advanced human lung high-resolution X-ray computed tomography (CT), we acquired quantitative micro-CT images. Three hLO types were observed during differentiation. Among them, alveolar hLOs highly expressed not only lung epithelial cell markers but also AMφ-specific markers. Furthermore, CD68+ AMφ-like cells were spatially organized on the luminal epithelial surface of alveolar hLOs. Bleomycin-treated alveolar hLOs showed upregulated expression of fibrosis-related markers and extracellular matrix deposits in the alveolar sacs. Alveolar hLOs also showed structural alterations such as excessive tissue fraction under bleomycin treatment. Therefore, we suggest that micro-CT analyzable PSC-derived alveolar hLOs are a promising in vitro model to predict lung toxicity manifestations, including fibrosis.


Subject(s)
Pluripotent Stem Cells , Pulmonary Fibrosis , Alveolar Epithelial Cells , Bleomycin/metabolism , Humans , Lung , Macrophages, Alveolar , Organoids , Pluripotent Stem Cells/metabolism , Pulmonary Fibrosis/chemically induced , Pulmonary Fibrosis/metabolism , X-Ray Microtomography
6.
Acta Cardiol Sin ; 38(1): 56-63, 2022 Jan.
Article in English | MEDLINE | ID: mdl-35068884

ABSTRACT

BACKGROUND: Coronary angiography (CA) or percutaneous coronary intervention (PCI) after transcatheter aortic valve replacement (TAVR) may become technically challenging after implantation of the self-expanding Medtronic CoreValve (MCV) device, which extends above the coronary ostia. The aim of this study was to investigate the incidence and feasibility of CA or PCI and the outcomes of PCI after TAVR with the MCV device. METHODS: From July 2014 to April 2020, among 209 patients treated with TAVR with a MCV device, 14 (7%) underwent CA or PCI after the procedure at a mean duration of 28 ± 15 months at our institution. RESULTS: The mean age of the patients was 83 ± 6 years. Thirteen (93%) patients underwent CA due to angina symptoms with a positive noninvasive test, and 1 underwent CA for acute coronary syndrome. Most of the CA and PCI procedures were performed through a radial approach: 11 patients (79%) via the right radial artery, 1 (7%) the left radial artery, and 2 (14%) through the right femoral artery. CA of the left and right coronary arteries was successfully achieved in 13 patients (93%) with Judkin left (3.5 to 5) diagnostic catheters and in 11 patients (79%) with Judkin right (4) diagnostic catheters. The second-line catheter of choice was the Amplatz left (AL) 1 catheter for the right coronary artery and AL 2 for the left coronary artery. Procedural success was achieved in all 5 patients who underwent post-TAVR PCI without procedural or in-hospital complications. The use of a Guideliner microcatheter facilitated stent delivery in one patient. CONCLUSIONS: Coronary angiography or PCI following TAVR with a MCV device is feasible and safe, but requires understanding of the three-dimensional geometry of the prosthetic valve and its relationship to the coronary ostia.

7.
BMC Immunol ; 22(1): 30, 2021 05 12.
Article in English | MEDLINE | ID: mdl-33980160

ABSTRACT

BACKGROUND: Triggering receptor expressed on myeloid cells 2 (TREM2) signaling is considered to regulate anti-inflammatory responses in macrophages, dendritic cell maturation, osteoclast development, induction of obesity, and Alzheimer's disease pathogenesis. However, little is known regarding the effect of TREM2 on natural killer (NK) cells. RESULTS: Here, we demonstrated for the first time that CD3-CD122+NK1.1+ precursor NK (pNK) cells expressed TREM2 and their population increased in TREM2-overexpressing transgenic (TREM2-TG) mice compared with that in female C57BL/6 J wild type (WT) mice. Both NK cell-activating receptors and NK cell-associated genes were expressed at higher levels in various tissues of TREM2-TG mice than in WT mice. In addition, bone marrow-derived hematopoietic stem cells (HSCs) of TREM2-TG mice (TG-HSCs) successfully differentiated into NK cells in vitro, with a higher yield from TG-HSCs than from WT-HSCs. In contrast, TREM2 signaling inhibition by TREM2-Ig or a phosphatidylinositol 3-kinase (PI3K) inhibitor affected the expression of the NK cell receptor repertoire and decreased the expression levels of NK cell-associated genes, resulting in significant impairment of NK cell differentiation. Moreover, in melanoma-bearing WT mice, injection of bone marrow cells from TREM2-TG mice exerted greater antitumor effects than that with cells from WT control mice. CONCLUSIONS: Collectively, our data clearly showed that TREM2 promoted NK cell development and tumor regression, suggesting TREM2 as a new candidate for cancer immunotherapy.


Subject(s)
Bone Marrow Cells/immunology , Killer Cells, Natural/immunology , Melanoma/immunology , Membrane Glycoproteins/metabolism , Receptors, Immunologic/metabolism , Animals , Bone Marrow Transplantation , CD3 Complex/metabolism , Cell Differentiation , Female , Humans , Immunotherapy, Adoptive , Interleukin-2 Receptor beta Subunit/metabolism , Melanoma/therapy , Melanoma, Experimental , Membrane Glycoproteins/genetics , Mice , Mice, Inbred C57BL , Mice, Transgenic , Neoplasms, Experimental , Receptors, Immunologic/genetics
8.
Opt Express ; 29(10): 15434-15442, 2021 May 10.
Article in English | MEDLINE | ID: mdl-33985243

ABSTRACT

In this paper, we propose a four-wave mixing-based photonic crystal fiber (PCF) microfluid sensor, and two U-shape microslits fabricated by a femtosecond laser are embedded into the sensor for real-time microfluid measurement. Theoretical and experimental results prove that the signal wavelength is sensitive to both the refractive index (RI) and the material dispersion property of the liquid sample filled into the air channels. For different aqueous target samples at low concentrations, the responses of signal wavelength are consistent with each other. The obtained RI sensitivity is approximately 881.36 nm/RIU, and the sensing resolution is around 1.6 × 10-4 RIU. The proposed sensor also shows a better figure of merit (FOM) as high as 313.65 RIU-1 when compared with the fiber SPR sensors. Besides, the signal wavelengths present different responses with the increasing aqueous concentration due to the separated dispersion characteristics of the filled liquid samples, which can be potentially applied for the discrimination of liquid samples with a well-designed wavelength-coded sensor array in the future.

9.
J Formos Med Assoc ; 120(1 Pt 1): 180-188, 2021 Jan.
Article in English | MEDLINE | ID: mdl-32402520

ABSTRACT

BACKGROUND/PURPOSE: Outlet-type VSD is frequently associated with aortic valve prolapse that surgery is frequently required. The literature regarding outcomes of transcatheter closure of outlet-type VSDs is scant. This study was conducted to know the safety and efficacy of transcatheter closure of outlet-type ventricular septal defects (VSDs) with Amplatzer Duct Occluder II (ADO II). METHODS: Medical records of patients underwent attempted transcatheter closure of outlet-type VSD with ADO II between October 2013 and August 2019 were retrospectively reviewed. RESULTS: Among 49 patients, transcatheter closure was successful in 45 (91.8%; 33 males and 12 females; mean [± standard deviation] age and body weight: 15.8 (±17.7) years and 36.6 (±23.3) kg, respectively). The median VSD diameter was 4.0 mm (range: 1.2-6.0 mm). Device closure failed in four because the sheath could not be advanced through a prograde or retrograde route in one patient, occluder embolization in the two patients, and failed right ventricular disc anchoring in one patient. After a mean follow-up of 22.7 months (range: 0.3-51.1 months), only nine (20.0%) patients had increased severity in aortic regurgitation (AR) on the echocardiography. Preprocedural AR decreased in severity or even disappeared in 11 (24.4%) patients. No heart block or device failure occurred during follow-up. A trivial-to-small residual shunt was detected in 19 patients (42.2%) in the most recent echocardiography. CONCLUSION: Transcatheter closure of outlet-type VSDs with ADO II is feasible. Although no significant aggravation of AR was observed in the short-to-mid-term follow-up, long-term follow-up is mandatory.


Subject(s)
Heart Septal Defects, Ventricular , Septal Occluder Device , Adolescent , Adult , Cardiac Catheterization , Child , Child, Preschool , Female , Heart Septal Defects, Ventricular/diagnostic imaging , Heart Septal Defects, Ventricular/surgery , Humans , Infant , Infant, Newborn , Male , Retrospective Studies , Septal Occluder Device/adverse effects , Treatment Outcome , Young Adult
10.
Sensors (Basel) ; 21(2)2021 Jan 09.
Article in English | MEDLINE | ID: mdl-33435476

ABSTRACT

Large-scale wireless sensor networks are characterized by stringent energy and computation restrictions. It is exceedingly difficult to change a sensor network's environment configurations, such as the number of sensor nodes, after deployment of the nodes. Although several simulators are able to variously construct simulation models for sensor networks before their deployment, the configurations should be modified with extra human effort as the simulators cannot freely generate diverse models. In this paper, we propose a novel framework, called a system entity structure and model base for large-scale wireless sensor networks (WSN-SES/MB), which is based on discrete event system specification formalism. Our proposed framework synthesizes the structure and models for sensor networks through our modeling construction process. The proposed framework achieves time and cost savings in constructing discrete event simulation-based models. In addition, the framework increases the diversity of simulation models by the process's pruning algorithm. The simulation results validate that the proposed framework provides up to 8% time savings and up to 23% cost savings as compared to the manual extra effort.

11.
Educ Technol Res Dev ; 69(5): 2729-2760, 2021.
Article in English | MEDLINE | ID: mdl-34426722

ABSTRACT

Prior to this study, a testable model for the influence of contextual knowledge (XK) on teacher candidates' intention to integrate technology into classroom instruction had not been established. We applied the Decomposed Theory of Planned Behavior (DTPB) to aid us in this effort. Our work (a) provided a theoretical conceptualization for factors of XK through application of the DTPB, (b) represented the synergistic effects among these factors, and (c) allowed us to explore their influences on teacher candidates' intentions to teach with technology. To assess our model, which includes factors such as teacher candidates' beliefs, attitudes, and efficacy, we developed an instrument, the Intention to Teach with Technology (IT2) Survey. Results from the structural equation model of the survey data indicated our model fit the data very well and readily accounted for various XK factors, the relations among these factors, and their influence on teacher candidates' intentions to integrate technology into teaching. Given the complexity of the context in any teaching situation, its relation to and influence on technology integration, and the previously limited examination of context in research and teacher development, the results indicate the proposed model is quite plausible, accounting for 75% of the variation in intention. The study demonstrates the IT2 Survey is an effective instrument to examine factors associated with XK and their influences on technology integration. Our work extends theory about technology integration by including XK and has implications for researchers as well as practitioners who seek to advance technology integration in preparation programs.

12.
Microcirculation ; 27(4): e12608, 2020 05.
Article in English | MEDLINE | ID: mdl-31991513

ABSTRACT

OBJECTIVE: We aimed to determine whether high-dose nitroglycerin, a nitric oxide donor, preserves erythrocyte deformability during cardiopulmonary bypass and examines the signaling pathway of nitric oxide in erythrocytes. METHODS: In a randomized and controlled fashion, forty-two patients undergoing cardiac surgery with hypothermic cardiopulmonary bypass were allocated to high-dose (N = 21) and low-dose groups (N = 21). During rewarming period, patients were given intravenous nitroglycerin with an infusion rate 5 and 1 µg·kg-1 ·min-1 in high-dose and low-dose groups, respectively. Tyrosine phosphorylation level of non-muscle myosin IIA in erythrocyte membrane was used as an index of erythrocyte deformability and analyzed using immunoblotting. RESULTS: Tyrosine phosphorylation of non-muscle myosin IIA was significantly enhanced after bypass in high-dose group (3.729 ± 1.700 folds, P = .011) but not low-dose group (1.545 ± 0.595 folds, P = .076). Phosphorylation of aquaporin 1, vasodilator-stimulated phosphoprotein, and focal adhesion kinase in erythrocyte membrane was also upregulated in high-dose group after bypass. Besides, plasma nitric oxide level was highly correlated with fold change of non-muscle myosin IIA phosphorylation (Pearson's correlation coefficient .871). CONCLUSIONS: High-dose nitroglycerin administered during cardiopulmonary bypass improves erythrocyte deformability through activating phosphorylation of aquaporin 1, vasodilator-stimulated phosphoprotein, and focal adhesion kinase in erythrocytes.


Subject(s)
Cardiac Surgical Procedures , Cardiopulmonary Bypass , Erythrocyte Deformability/drug effects , Hypothermia, Induced , Nitroglycerin/administration & dosage , Rewarming , Vasodilator Agents/administration & dosage , Aged , Female , Humans , Male , Middle Aged
13.
Eur J Clin Invest ; 50(1): e13183, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31691961

ABSTRACT

BACKGROUND: Being woman is associated with higher survival rates after transcatheter aortic valve replacement (TAVR) despite the increase in periprocedural complications. The left ventricle (LV) remodelling process that follows TAVR is considered to play an important role. We aim to investigate whether gender difference affects the process of LV remodelling after TAVR. MATERIALS AND METHODS: A total of 100 patients (50 men and 50 women) after TAVR were enrolled. Echocardiography was performed at baseline before the TAVR procedure and repeated upon discharge, and at three, nine and 12 months post-TAVR. RESULTS: Women exhibited an early regression of LV mass and the LV mass index (LVMi) decreased 12.0% from 148.3 ± 48.0 to 130.5 ± 43.7 g/m2 at just a median of 17 days after the procedure (P < .001). Almost one-half of the LVMi regression occurred by 17 days post-TAVR and the LVMi regressed 22.0% by 12 months post-TAVR. In contrast, the regression of LVMi in men seemed to be more gradual and the significant regression of LVMi from baseline began to be observed since three months later after TAVR. The LVMi reduction at nine months was 11.5% and achieved 15.4% over one year. Multivariable logistic regression analysis showed only the female sex, better LVEF and greater baseline LVMi were independently associated with greater LVMi regression after TAVR, indicating female gender is an independent predictor for favourable LV remodelling after TAVR. CONCLUSION: In conclusion, female patients with AS had favourable reverse remodelling with greater and earlier LV mass regression post-TAVR compared with the male patients.


Subject(s)
Aortic Valve Stenosis/surgery , Hypertrophy, Left Ventricular/diagnostic imaging , Transcatheter Aortic Valve Replacement , Ventricular Remodeling , Aged , Aged, 80 and over , Aortic Valve Stenosis/complications , Echocardiography , Female , Humans , Hypertrophy, Left Ventricular/etiology , Male , Recovery of Function , Severity of Illness Index , Sex Factors , Time Factors
14.
FASEB J ; 33(12): 13386-13397, 2019 12.
Article in English | MEDLINE | ID: mdl-31550172

ABSTRACT

Gut-homing γδ T cells are induced by chemokines and cell adhesion molecules and play a critical role in homeostasis and mucosal immunity; however, little is known regarding their upstream regulators. We investigated the role of Axl as a specific regulator of chemokines and cell adhesion molecule in the distribution of intestinal γδ T cells. The population of γδ T-cell receptor-positive cells including Vγ1 and Vγ7 subsets was remarkably increased in the intraepithelial lymphocytes of Axl-/- mice compared with those of wild-type (WT) mice. An increased number of migrated γδ T cells were observed in the coculture with intraepithelial cells from Axl-/- mice. The mRNA expression level of chemokine (C-C motif) ligand (CCL) 25 was specifically higher in the small intestine of Axl-/- mice than in WT mice. In adoptive transfer, the migration of both thymic and extrathymic γδ T cells was increased in Axl-/- mice. The activation of Axl signaling down-regulated CCL25 expression via ERK signaling pathway and reduced the population of γδ T cells. Systemic dissemination was suppressed in Axl-/- mice infected with Salmonella typhimurium. Thus, our findings suggest that Axl plays a critical role in regulating the migration of γδ T cells for the maintenance of homeostasis and bacterial resistance.-Kim, S.-M., Park, M., Yee, S.-M., Ji, K.-Y., Lee, E.-H., Nguyen, T.-V., Nguyen, T. H.-L., Jang, J., Kim, E.-M., Choi, H.-R., Yun, C.-H., Kang, H.-S. Axl is a key regulator of intestinal γδ T-cell homeostasis.


Subject(s)
Epithelial Cells/immunology , Homeostasis , Intestine, Small/immunology , Proto-Oncogene Proteins/physiology , Receptor Protein-Tyrosine Kinases/physiology , Receptors, Antigen, T-Cell, gamma-delta/immunology , T-Lymphocyte Subsets/immunology , Typhoid Fever/immunology , Animals , Cell Movement , Cells, Cultured , Chemokines, CC/metabolism , Epithelial Cells/metabolism , Epithelial Cells/microbiology , Immunity, Mucosal , Intestinal Mucosa/immunology , Intestinal Mucosa/metabolism , Intestinal Mucosa/microbiology , Intestine, Small/metabolism , Intestine, Small/microbiology , Mice , Mice, Inbred C57BL , Mice, Knockout , Receptors, Antigen, T-Cell, gamma-delta/metabolism , Salmonella typhimurium/physiology , Typhoid Fever/metabolism , Typhoid Fever/microbiology , Axl Receptor Tyrosine Kinase
15.
J Phys Chem A ; 124(19): 3924-3934, 2020 May 14.
Article in English | MEDLINE | ID: mdl-32286064

ABSTRACT

Acoustic vibrations in plasmonic nanoparticles, monitored by an all-optical means, have attracted significant increasing interest because they provide unique insight into the mechanical properties of these metallic nanostructures. Al nanostructures are a recently emerging alternative to noble metal nanoparticles, because their broad wavelength tunability and high natural abundance make them ideal for many potential applications. Here, we investigate the acoustic vibrations of individual Al nanocrystals using a combination of electron microscopy and single-particle transient extinction spectroscopy, made possible with a low-pulse energy, high sensitivity, and probe-wavelength-tunable, single-particle transient extinction microscope. For chemically synthesized, faceted Al nanocrystals, the observed vibration frequency scales with the inverse particle diameter. In contrast, triangularly shaped Al nanocrystals support two distinct frequencies, corresponding to their in- and out-of-plane breathing modes. Unlike ensemble measurements, which measure average properties, measuring the damping time of the acoustic vibrations for individual particles enables us to investigate variations of the quality factor on the particle-to-particle level. Surprisingly, we find a large variation in quality factors even for nanocrystals of similar size and shape. This observed heterogeneity appears to result from substantially varying degrees of nanoparticle crystallinity even for chemically synthesized nanocrystals.

16.
Proc Natl Acad Sci U S A ; 114(44): 11621-11626, 2017 10 31.
Article in English | MEDLINE | ID: mdl-29078373

ABSTRACT

Plasmon hybridization theory, inspired by molecular orbital theory, has been extremely successful in describing the near-field coupling in clusters of plasmonic nanoparticles, also known as plasmonic molecules. However, the vibrational modes of plasmonic molecules have been virtually unexplored. By designing precisely configured plasmonic molecules of varying complexity and probing them at the individual plasmonic molecule level, intramolecular coupling of acoustic modes, mediated by the underlying substrate, is observed. The strength of this coupling can be manipulated through the configuration of the plasmonic molecules. Surprisingly, classical continuum elastic theory fails to account for the experimental trends, which are well described by a simple coupled oscillator picture that assumes the vibrational coupling is mediated by coherent phonons with low energies. These findings provide a route to the systematic optical control of the gigahertz response of metallic nanostructures, opening the door to new optomechanical device strategies.

17.
Nano Lett ; 19(5): 3091-3097, 2019 05 08.
Article in English | MEDLINE | ID: mdl-30935208

ABSTRACT

Aluminum nanostructures are a promising alternative material to noble metal nanostructures for several photonic and catalytic applications, but their ultrafast electron dynamics remain elusive. Here, we combine single-particle transient extinction spectroscopy and parameter-free first-principles calculations to investigate the non-equilibrium carrier dynamics in aluminum nanostructures. Unlike gold nanostructures, we find the sub-picosecond optical response of lithographically fabricated aluminum nanodisks to be more sensitive to the lattice temperature than the electron temperature. We assign the rise in the transient transmission to electron-phonon coupling with a pump-power-independent lifetime of 500 ± 100 fs and theoretically confirm this strong electron-phonon coupling behavior. We also measure electron-phonon lifetimes in chemically synthesized aluminum nanocrystals and find them to be even longer (1.0 ± 0.1 ps) than for the nanodisks. We also observe a rise and decay in the transient transmissions with amplitudes that scale with the surface-to-volume ratio of the aluminum nanodisks, implying a possible hot carrier trapping and detrapping at the native oxide shell-metal core interface.

18.
Nano Lett ; 18(6): 3494-3501, 2018 06 13.
Article in English | MEDLINE | ID: mdl-29715035

ABSTRACT

The study of acoustic vibrations in nanoparticles provides unique and unparalleled insight into their mechanical properties. Electron-beam lithography of nanostructures allows precise manipulation of their acoustic vibration frequencies through control of nanoscale morphology. However, the dissipation of acoustic vibrations in this important class of nanostructures has not yet been examined. Here we report, using single-particle ultrafast transient extinction spectroscopy, the intrinsic damping dynamics in lithographically fabricated plasmonic nanostructures. We find that in stark contrast to chemically synthesized, monocrystalline nanoparticles, acoustic energy dissipation in lithographically fabricated nanostructures is solely dominated by intrinsic damping. A quality factor of Q = 11.3 ± 2.5 is observed for all 147 nanostructures, regardless of size, geometry, frequency, surface adhesion, and mode. This result indicates that the complex Young's modulus of this material is independent of frequency with its imaginary component being approximately 11 times smaller than its real part. Substrate-mediated acoustic vibration damping is strongly suppressed, despite strong binding between the glass substrate and Au nanostructures. We anticipate that these results, characterizing the optomechanical properties of lithographically fabricated metal nanostructures, will help inform their design for applications such as photoacoustic imaging agents, high-frequency resonators, and ultrafast optical switches.

19.
Bioorg Chem ; 81: 27-34, 2018 12.
Article in English | MEDLINE | ID: mdl-30092384

ABSTRACT

Poria cocos Wolf confers edible sclerotia also known as 'Indian bread' in North America, that have been used for the treatment of various diseases in Asian countries. As part of our ongoing aim to identify biologically new metabolites from Korean edible mushrooms, we investigated the ethanol (EtOH) extract of the sclerotia of P. cocos by applying a comparative LC/MS- and bioassay-based analysis approach, since the EtOH extract reciprocally regulated adipocyte and osteoblast differentiation in mouse mesenchymal stem cells (MSCs). Bioassay-based analysis of the EtOH extract led to the successful isolation of two sterols, ergosterol peroxide (1) and 9,11-dehydroergosterol peroxide (2); three diterpenes, dehydroabietic acid (3), 7-oxocallitrisic acid, (4) and pimaric acid (5); and two triterpenes, dehydroeburicoic acid monoacetate (6) and eburicoic acid acetate (7) from the active hexane-soluble fraction. The isolated compounds (1-7) were examined for their effects on the regulation of MSC differentiation. The two sterols (1 and 2) were able to suppress MSC differentiation toward adipocytes. In contrast, the three diterpenes (3-5) showed activity to promote osteogenic differentiation of MSC. These findings demonstrate that the EtOH extract of P. cocos sclerotia is worth consideration as a new potential source of bioactive compounds effective in the treatment of osteoporosis in the elderly, since the extract contains sterols that inhibit adipogenic differentiation as well as diterpenes that promote osteogenic differentiation from MSCs.


Subject(s)
Adipocytes/drug effects , Osteoblasts/drug effects , Wolfiporia/chemistry , Abietanes/chemistry , Abietanes/isolation & purification , Abietanes/pharmacology , Animals , Cell Differentiation/drug effects , Cells, Cultured , Diterpenes/chemistry , Diterpenes/isolation & purification , Diterpenes/pharmacology , Dose-Response Relationship, Drug , Mice , Molecular Structure , Peroxides/chemistry , Peroxides/isolation & purification , Peroxides/pharmacology , Sterols/chemistry , Sterols/isolation & purification , Sterols/pharmacology , Structure-Activity Relationship
20.
BMC Complement Altern Med ; 18(1): 39, 2018 Jan 30.
Article in English | MEDLINE | ID: mdl-29382339

ABSTRACT

BACKGROUND: Hesperidin is a flavonoid with antioxidant, anti-inflammatory, and immune modulatory activities. Photoaging is a consequence of chronic exposure to the sun and ultraviolet (UV) radiation. This study was designed to evaluate the efficacy of hesperidin against photoaging of dorsal skin in hairless mice. METHODS: Hairless male mice (6-week-old) were divided into three groups (n = 7): control, UVB-treated vehicle, and UVB-treated hesperidin groups. UVB-irradiated mice from hesperidin group were orally administered 0.1 mL of water containing 100 mg/kg body weight per day hesperidin. RESULTS: The mean length and depth of wrinkles in the UVB-treated hesperidin group significantly improved after the oral administration of hesperidin, which significantly inhibited the increase in epidermal thickness and epidermal hypertrophy (P < 0.05). UVB irradiation of mice induced epidermal barrier dysfunction including an increase in the transepidermal water loss (TEWL); however, hesperidin decreased the TEWL. UVB irradiation increased the expression of MMP-9 and pro-inflammatory cytokines whereas UVB-treated hesperidin group showed reduced expression. These results indicate that hesperidin showed anti-photoaging activity in the UVB-irradiated hairless mice. In conclusion, hesperidin inhibited the UVB-induced increase in skin thickness, wrinkle formation, and collagen fiber loss in male hairless mice. CONCLUSIONS: These results suggest that hesperidin shows potent anti-photoaging activity by regulating MMP-9 expression through the suppression of MAPK-dependent signaling pathways.


Subject(s)
Antioxidants/pharmacology , Hesperidin/pharmacology , MAP Kinase Signaling System/drug effects , Matrix Metalloproteinase 9/metabolism , Skin Aging/drug effects , Animals , Down-Regulation/drug effects , Epidermis/drug effects , Epidermis/radiation effects , Immunohistochemistry , Male , Mice , Mice, Hairless , Skin Aging/radiation effects , Ultraviolet Rays
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