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1.
Opt Express ; 24(19): 21910-20, 2016 Sep 19.
Article in English | MEDLINE | ID: mdl-27661926

ABSTRACT

We report on measurement of small displacements with sub-nanometer precision using an optoelectronic oscillator (OEO) with an intra-loop Michelson interferometer. In comparison with conventional homodyne and heterodyne detection methods, where displacement appears as a power change or a phase shift, respectively, in the OEO detection, the displacement produces a shift in the oscillation frequency. In comparison with typical OEO sensors, where the frequency shift is proportional to the OEO oscillation frequency in radio-frequency domain, the frequency shift in our method with an intra-loop interferometer is proportional to an optical frequency. We constructed a hybrid apparatus and compared characteristics of the OEO and heterodyne detection methods.

2.
Chem Biodivers ; 12(4): 538-46, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25879499

ABSTRACT

We investigated the modulation of innate and adaptive immune cell activation by Eucommia ulmoides Oliver extract (EUE) and its ingredient genipin. As an innate immunity indicator, the phagocytic activity of macrophages was determined by measuring engulfed, fluorescently labeled Escherichia coli. As a surrogate marker for the respective activation of cellular and humoral adaptive immunity, concanavalin A (Con A) and lipopolysaccharide (LPS) induction of primary splenocyte proliferation was assayed in in vitro and ex vivo systems. EUE and genipin suppressed the proliferation of primary splenic lymphocytes induced by Con A or LPS, but not macrophage phagocytosis. Oral administration of EUE and genipin to mice decreased splenic lymphocyte proliferation induced by Con A or LPS. These results revealed that E. ulmoides and genipin suppressed cellular and humoral adaptive immunity, and they suggest that E. ulmoides and genipin are promising candidates for immunosuppressive drugs that target diseases that involve excessive activation of adaptive immunity.


Subject(s)
Eucommiaceae/chemistry , Immunosuppressive Agents/pharmacology , Iridoids/pharmacology , Lymphocytes/drug effects , Plant Extracts/pharmacology , Adaptive Immunity/drug effects , Administration, Oral , Animals , Cell Proliferation/drug effects , Concanavalin A/pharmacology , Iridoids/administration & dosage , Lipopolysaccharides/pharmacology , Macrophages/drug effects , Male , Mice, Inbred BALB C , Phagocytosis/drug effects , Plant Extracts/chemistry , Spleen/cytology , Spleen/drug effects
3.
Nanotechnology ; 25(4): 045604, 2014 Jan 31.
Article in English | MEDLINE | ID: mdl-24398944

ABSTRACT

We studied exchange coupled composite (ECC) media with an out-of-plane easy axis consisting of hard magnetic L1(0) chemically ordered FePtCu alloy films and magnetically softer [Co/Pt](N) multilayer stacks. By tailoring the structural properties of the ternary FePtCu alloy and [Co/Pt](N) multilayers, we can tune the magnetic parameters of the composite in a wide range. This allowed us to address experimentally one of the most crucial properties determining the performance of ECC media, namely the pinning field of the magnetic domain wall present at the interface between the hard and soft layers. We demonstrate that the pinning field is proportional to the difference of the magnetic anisotropy constants of the hard and soft layers, which confirms the theoretical predictions. Furthermore, we show that the pinning field can be efficiently decreased after an additional annealing step. Transmission electron microscopy investigations indicated that the origin of the observed effect is due to a heat-induced phase transformation of iron oxide present at the interface between the hard and soft layers. This study reveals that tailoring the properties of the hard/soft interface is another efficient tuning knob for optimization of the performance of ECC media.

4.
Biol Pharm Bull ; 36(12): 1928-35, 2013.
Article in English | MEDLINE | ID: mdl-24292051

ABSTRACT

The anti-inflammatory and neuroprotective effects of trans-cinnamaldehyde (TCA) were investigated on the inflammatory cells and the dopaminergic degeneration in mice. TCA inhibited the up-regulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the lipopolysaccharide (LPS)-induced inflammatory BV2 microglial cells. To investigate the TCA efficacy on the 6-hydroxydopamine (6-OHDA)-induced dopaminergic degeneration in mice, an intracerebroventricular injection of 6-OHDA was given to the mice, and TCA (30 mg/kg) was intraperitoneally administered. At 7 d after the 6-OHDA injection, 6-OHDA led to a severe loss of tyrosine hydroxylase (TH)-positive dopaminergic neurons in the striatum and substantia nigra (SN). On the other hand, TCA dramatically maintained the number of TH-positive dopaminergic neurons in the striatum and SN regions of the 6-OHDA-treated mice, which indicates that TCA is able to inhibit the 6-OHDA-induced reduction of TH expression in the dopaminergic neurons in the striatum and SN regions. TCA also inhibited the induction of iNOS and COX-2 in the 6-OHDA model, similarly as shown in the LPS-induced inflammatory BV2 microglial cells. These results indicate that TCA has a neuroprotective effect on dopaminergic neurons and that this effect may be associated with the inhibition of inflammatory responses. These findings suggest that TCA may be a therapeutic candidate for the prevention of inflammation-mediated neurodegenerative diseases.


Subject(s)
Acrolein/analogs & derivatives , Anti-Inflammatory Agents/pharmacology , Neuroprotective Agents/pharmacology , Acrolein/pharmacology , Animals , Cell Line , Cell Survival/drug effects , Corpus Striatum/drug effects , Corpus Striatum/metabolism , Corpus Striatum/pathology , Cyclooxygenase 2/metabolism , Dopaminergic Neurons/drug effects , Dopaminergic Neurons/pathology , Lipopolysaccharides , Male , Mice , Mice, Inbred ICR , Nitric Oxide/metabolism , Nitric Oxide Synthase Type II/metabolism , Oxidopamine , Substantia Nigra/drug effects , Substantia Nigra/metabolism , Substantia Nigra/pathology , Tyrosine 3-Monooxygenase/metabolism
5.
J Nanosci Nanotechnol ; 13(3): 1830-3, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23755600

ABSTRACT

Titanium carbide (TiC) particles have been coated with aluminum (Al) phase to enhance the compatibility with a metal matrix based on Al, expecting the homogenous dispersion of TiC particles into the matrix. The TiC particles were uniformly dispersed in the aqueous solution of pH 12. The aluminum nitrate as a precursor of Al phase was added to the solution dispersed with the TiC particles. The coating of Al phase onto the TiC particle was driven by the attractive force between the TiC particle with a negative charge and the Al cation in the aqueous solution. The TiC was not oxidized after heat treatment at 500 degrees C, whereas titanium dioxide peaks are detected after heat treatment at 1000 degrees C. In addition, the Al phase coated on the TiC surface was converted to amorphous alumina (Al2O3) and crystallized into alpha-Al2O3 during heat treatment at 500 and 1000 degrees C, respectively. The heat treatment condition such as atmosphere and temperature was an important factor in fabricating the reinforcing particles without degradation such as oxidation and phase transformation. The nano-sized Al2O3 coated reinforcing particles could be well fabricated using electrostatic force in the aqueous solution and by controlling the heat treatment condition.

6.
RSC Adv ; 13(10): 6564-6572, 2023 Feb 21.
Article in English | MEDLINE | ID: mdl-36874939

ABSTRACT

Passivation of precipitation-hardened UNS N07718 in 5 wt% NaCl + 0.5 wt% CH3COOH was investigated. Cyclic potentiodynamic polarisation revealed that the alloy surface was passivated without active-passive transition behaviour. The alloy surface was in a stable passive state during potentiostatic polarisation at 0.5 VSSE for 12 h. Bode and Mott-Schottky plots showed that the passive film became electrically resistive and less defective with n-type semiconductive properties during the polarisation. X-ray photoelectron spectra revealed that Cr- and Fe-enriched hydro/oxide layers were formed on the outer and inner layers of the passive film, respectively. The thickness of the film was almost constant with the increase of the polarisation time. The outer Cr-hydroxide layer changed into a Cr-oxide layer during the polarisation, resulting in a decreased donor density in the passive film. The film's composition change during the polarisation should be related to the corrosion resistance of the alloy in the shallow sour conditions.

7.
RSC Adv ; 13(28): 19220-19226, 2023 Jun 22.
Article in English | MEDLINE | ID: mdl-37377873

ABSTRACT

Preferential dissolution behaviour of the austenite (γ) phase in Fe-27Cr-xC high chromium cast irons (HCCIs) immersed in 0.1 mol dm-3 H2SO4 + 0.05 mol dm-3 HCl was investigated. Potentiodynamic and potentiostatic polarisation revealed that the primary and eutectic γ phases dissolved preferentially at -0.35 and 0.00 VSilver Silverchloride Electrode potential in sat. KCl (SSE), respectively. The immersion of the HCCIs in the solution showed that the dissolution of the primary γ phase dominated for ca. 1 h, while the primary and eutectic γ phases dissolved after ca. 1 h. However, the carbide phases remained undissolved during the dissolution of the γ phases. Furthermore, the corrosion rate of the HCCIs increased with the increasing C content owing to the increase in the contact potential difference values of the γ and carbide phases. The change in electromotive force due to C addition was related to the accelerated corrosion rate of the γ phases.

8.
BMC Med Genomics ; 16(1): 320, 2023 12 08.
Article in English | MEDLINE | ID: mdl-38066485

ABSTRACT

BACKGROUND: TMC1, which encodes transmembrane channel-like protein 1, forms the mechanoelectrical transduction (MET) channel in auditory hair cells, necessary for auditory function. TMC1 variants are known to cause autosomal dominant (DFNA36) and autosomal recessive (DFNB7/11) non-syndromic hearing loss, but only a handful of TMC1 variants underlying DFNA36 have been reported, hampering analysis of genotype-phenotype correlations. METHODS: In this study, we retrospectively reviewed 338 probands in an in-house database of genetic hearing loss, evaluating the clinical phenotypes and genotypes of novel TMC1 variants associated with DFNA36. To analyze the structural impact of these variants, we generated two structural models of human TMC1, utilizing the Cryo-EM structure of C. elegans TMC1 as a template and AlphaFold protein structure database. Specifically, the lipid bilayer-embedded protein database was used to construct membrane-embedded models of TMC1. We then examined the effect of TMC1 variants on intramolecular interactions and predicted their potential pathogenicity. RESULTS: We identified two novel TMC1 variants related to DFNA36 (c.1256T > C:p.Phe419Ser and c.1444T > C:p.Trp482Arg). The affected subjects had bilateral, moderate, late-onset, progressive sensorineural hearing loss with a down-sloping configuration. The Phe419 residue located in the transmembrane domain 4 of TMC1 faces outward towards the channel pore and is in close proximity to the hydrophobic tail of the lipid bilayer. The non-polar-to-polar variant (p.Phe419Ser) alters the hydrophobicity in the membrane, compromising protein-lipid interactions. On the other hand, the Trp482 residue located in the extracellular linker region between transmembrane domains 5 and 6 is anchored to the membrane interfaces via its aromatic rings, mediating several molecular interactions that stabilize the structure of TMC1. This type of aromatic ring-based anchoring is also observed in homologous transmembrane proteins such as OSCA1.2. Conversely, the substitution of Trp with Arg (Trp482Arg) disrupts the cation-π interaction with phospholipids located in the outer leaflet of the phospholipid bilayer, destabilizing protein-lipid interactions. Additionally, Trp482Arg collapses the CH-π interaction between Trp482 and Pro511, possibly reducing the overall stability of the protein. In parallel with the molecular modeling, the two mutants degraded significantly faster compared to the wild-type protein, compromising protein stability. CONCLUSIONS: This results expand the genetic spectrum of disease-causing TMC1 variants related to DFNA36 and provide insight into TMC1 transmembrane protein-lipid interactions.


Subject(s)
Hearing Loss, Sensorineural , Membrane Proteins , Animals , Humans , Caenorhabditis elegans , Hearing Loss, Sensorineural/genetics , Lipid Bilayers , Membrane Proteins/genetics , Retrospective Studies
9.
RSC Adv ; 13(1): 586-593, 2022 Dec 19.
Article in English | MEDLINE | ID: mdl-36605627

ABSTRACT

The effect of adding C on the passivity of hypoeutectic high chromium cast iron (HCCI) was investigated in a pH 8.4 boric-borate buffer solution. The microstructure of HCCI is composed of austenite and carbide phases, whose fractions and chemical compositions are influenced by the amount of C added. Electrochemical and surface analyses revealed that the addition of C in the HCCI increased the defect densities in the n-type and p-type semiconductive oxide layers on the austenite and carbide phases, respectively.

10.
J Sep Sci ; 34(6): 651-8, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21312331

ABSTRACT

A simple and sensitive reversed-phase (RP) HPLC coupled with pulsed amperometric detection (PAD) method was developed to determine the saikosaponin content in Bupleuri Radix or Caihu-shugan-san. Four saikosaponins in Bupleuri Radix and Caihu-shugan-san were extracted with a 6:4 solution of 10 mM sodium phosphate buffer (pH 8)/100% ethanol. Pulsed amperometric detection of carbohydrates in four major saikosaponins was highly sensitive when used with a water-acetonitrile gradient on an alkaline RP column with a post-column delivery system. The limits of detection (S/N=3) and of quantification (S/N=10) of saikosaponins were 0.01-0.02 and 0.03-0.05 µg/mL, respectively. The intra- and inter-day precision (RSDs) were each <9.7% and the average recoveries were 95.0-97.6% in Bupleuri Radix. This method can be used to analyze saikosaponins in Bupleuri Radix and Caihu-shugan-san.


Subject(s)
Bupleurum/chemistry , Chromatography, High Pressure Liquid/methods , Chromatography, Reverse-Phase/methods , Drugs, Chinese Herbal/analysis , Oleanolic Acid/analogs & derivatives , Saponins/analysis , Chromatography, High Pressure Liquid/instrumentation , Chromatography, Reverse-Phase/instrumentation , Oleanolic Acid/analysis
11.
Chem Pharm Bull (Tokyo) ; 59(6): 742-6, 2011.
Article in English | MEDLINE | ID: mdl-21628911

ABSTRACT

A new minor polyoxygenated triterpene named glutinolic acid (1) and two new aeginetic acid quinovosides (2, 3) were isolated from the roots of Rehmannia glutinosa LIBOSCH. (Scrophulariaceae) cultivated in Gunwi-gun, Korea. The structures of these compounds were established as 3α,19α,20ß,24,30-pentahydroxyurs-12-en-28-oic acid (1, glutinolic acid), aeginetic acid 5-O-ß-D-quinovoside (2) and aeginetoyl ajugol 5″-O-ß-D-quinovoside (3) on the basis of chemical and spectroscopic evidence.


Subject(s)
Disaccharides/chemistry , Monosaccharides/chemistry , Rehmannia/chemistry , Triterpenes/chemistry , Disaccharides/isolation & purification , Magnetic Resonance Spectroscopy , Molecular Conformation , Monosaccharides/isolation & purification , Plant Roots/chemistry , Triterpenes/isolation & purification
12.
Sci Rep ; 11(1): 3792, 2021 Feb 15.
Article in English | MEDLINE | ID: mdl-33589666

ABSTRACT

The macroscopic properties of permanent magnets and the resultant performance required for real implementations are determined by the magnets' microscopic features. However, earlier micromagnetic simulations and experimental studies required relatively a lot of work to gain any complete and comprehensive understanding of the relationships between magnets' macroscopic properties and their microstructures. Here, by means of supervised learning, we predict reliable values of coercivity (µ0Hc) and maximum magnetic energy product (BHmax) of granular NdFeB magnets according to their microstructural attributes (e.g. inter-grain decoupling, average grain size, and misalignment of easy axes) based on numerical datasets obtained from micromagnetic simulations. We conducted several tests of a variety of supervised machine learning (ML) models including kernel ridge regression (KRR), support vector regression (SVR), and artificial neural network (ANN) regression. The hyper-parameters of these models were optimized by a very fast simulated annealing (VFSA) algorithm with an adaptive cooling schedule. In our datasets of randomly generated 1,000 polycrystalline NdFeB cuboids with different microstructural attributes, all of the models yielded similar results in predicting both µ0Hc and BHmax. Furthermore, some outliers, which deteriorated the normality of residuals in the prediction of BHmax, were detected and further analyzed. Based on all of our results, we can conclude that our ML approach combined with micromagnetic simulations provides a robust framework for optimal design of microstructures for high-performance NdFeB magnets.

13.
J Phys Chem Lett ; 12(25): 6000-6006, 2021 Jul 01.
Article in English | MEDLINE | ID: mdl-34165310

ABSTRACT

Machine-learning (ML) techniques have drawn an ever-increasing focus as they enable high-throughput screening and multiscale prediction of material properties. Especially, ML force fields (FFs) of quantum mechanical accuracy are expected to play a central role for the purpose. The construction of ML-FFs for polymers is, however, still in its infancy due to the formidable configurational space of its composing atoms. Here, we demonstrate the effective development of ML-FFs using kernel functions and a Gaussian process for an organic polymer, polytetrafluoroethylene (PTFE), with a data set acquired by first-principles calculations and ab initio molecular dynamics (AIMD) simulations. Even though the training data set is sampled only with short PTFE chains, structures of longer chains optimized by our ML-FF show an excellent consistency with density functional theory calculations. Furthermore, when integrated with molecular dynamics simulations, the ML-FF successfully describes various physical properties of a PTFE bundle, such as a density, melting temperature, coefficient of thermal expansion, and Young's modulus.

14.
J Nat Prod ; 72(10): 1895-8, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19757853

ABSTRACT

Three new phenolic compounds, (E)-4'-demethyl-6-methyleucomin (1), anemarcoumarin A (2), and anemarchalconyn (3), were isolated from an ethyl acetate extract of the rhizomes of Anemarrhena asphodeloides, together with seven known compounds (4-10). The structures of the new compounds (1-3) were determined on the basis of spectroscopic data interpretation. Compound 3 exhibited a potent inhibitory effect against the differentiation of preadipocyte 3T3-L1 cells with an IC50 value of 5.3 microM.


Subject(s)
Adipogenesis/drug effects , Anemarrhena/chemistry , Coumarins/isolation & purification , Coumarins/pharmacology , Phenols/isolation & purification , Phenols/pharmacology , Plants, Medicinal/chemistry , 3T3-L1 Cells/drug effects , Animals , Coumarins/chemistry , Korea , Mice , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Phenols/chemistry , Rhizome/chemistry
15.
Biol Pharm Bull ; 32(8): 1433-8, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19652386

ABSTRACT

Coptidis Rhizoma and its isolated alkaloids are reported to possess a variety of activities, including neuroprotective and antioxidant effects. Thus, the anti-Alzheimer and antioxidant effects of six protoberberine alkaloids (berberine, palmatine, jateorrhizine, epiberberine, coptisine, and groenlandicine) and one aporphine alkaloid (magnoflorine) from Coptidis Rhizoma were evaluated via beta-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) assays, along with peroxynitrite (ONOO(-)) scavenging and total reactive oxygen species (ROS) inhibitory assays. Six protoberberine alkaloids exhibited predominant cholinesterases (ChEs) inhibitory effects with IC(50) values ranging between 0.44-1.07 microM for AChE and 3.32-6.84 microM for BChE; only epiberberine (K(i)=10.0) and groenlandicine (K(i)=21.2) exerted good, non-competitive BACE1 inhibitory activities with IC(50) values of 8.55 and 19.68 microM, respectively. In two antioxidant assays, jateorrhizine and groenlandicine exhibited significant ONOO(-) scavenging activities with IC(50) values of 0.78 and 0.84 microM, respectively; coptisine and groenlandicine exhibited moderate total ROS inhibitory activities with IC(50) values of 48.93 and 51.78 microM, respectively. These results indicate that Coptidis Rhizoma alkaloids have a strong potential of inhibition and prevention of Alzheimer's disease (AD) mainly through both ChEs and beta-amyloids pathways, and additionally through antioxidant capacities. In particular, groenlandicine may be a promising anti-AD agent due to its potent inhibitory activity of both ChEs and beta-amyloids formation, as well as marked ONOO(-) scavenging and good ROS inhibitory capacities. As a result, Coptidis Rhizoma and the alkaloids contained therein would clearly have beneficial uses in the development of therapeutic and preventive agents for AD and oxidative stress-related disease.


Subject(s)
Alkaloids/pharmacology , Alzheimer Disease/drug therapy , Antioxidants/pharmacology , Drugs, Chinese Herbal/chemistry , Acetylcholinesterase/metabolism , Alkaloids/isolation & purification , Alkaloids/therapeutic use , Alzheimer Disease/enzymology , Alzheimer Disease/metabolism , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Antioxidants/isolation & purification , Antioxidants/therapeutic use , Aspartic Acid Endopeptidases/antagonists & inhibitors , Butyrylcholinesterase/metabolism , Coptis/chemistry , Coptis chinensis , Humans , Inhibitory Concentration 50 , Molecular Structure , Reactive Oxygen Species/metabolism , Spectrophotometry , Substrate Specificity
16.
Arch Pharm Res ; 32(10): 1399-408, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19898803

ABSTRACT

Fourteen diterpenes were isolated from the n-hexane fraction of the roots of Aralia cordata (syn. = A. continentalis). Through spectroscopy, the chemical structures were determined as: ent-pimara-8(14),15-diene-19-oic acid (1); ent-kaur-16-en-19-oic-acid (2); 18-nor-ent-pimara-8(14),15-diene-4beta-ol (3); 18-nor-ent-kaur-16-ene-4beta-ol (4); ent-pimara-8(14),15-diene-19-ol (5); 7alpha-hydroxy-ent-pimara-8(14),15-diene-19-oic acid (6); 7beta-hydroxy-ent-pimara-8(14),15-diene-19-oic acid (7); ent-pimar-15-en-8alpha,19-diol (8); 7-oxo-ent-pimara-8(14),15-diene-19-oic acid (9); 16alpha-hydroxy-17-isovaleroyloxy-ent-kauran-19-oic acid (10); 17-hydroxy-ent-kaur-15-en-19-oic acid (11); 15alpha,16alpha-epoxy-17-hydroxy-ent-kauran-19-oic acid (12); 16alpha,17-dihydroxy-ent-kauran-19-oic acid (13); and 16alpha-methoxy-17-hydroxy-ent-kauran-19-oic acid (14). Compounds 4, 5, 8, 12, and 14 were first isolated from this plant. The anti-Alzheimer and antioxidant effects of ent-pimarane-type diterpenes 1, 3, 5, 8, and 9, as well as ent-kaurane-type diterpenes 2, 4, and 10-13, were evaluated via beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), peroxynitrite (ONOO(-)), and nitric oxide (NO*) assays. Of the compounds tested, 8 exerted the most effective BChE inhibition with an IC(50) value of 7.58 microM, followed by 3, 13, 11, 2, and 10. Compounds 9-11 exhibited good BACE1 inhibitory activities with IC(50) values of 18.58-24.10 microM. However, 11 showed marginal AChE inhibitory effect, and all compounds tested showed no scavenging activities on ONOO(-) and NO* at a concentration of 100 microM.


Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Aralia/chemistry , Aspartic Acid Endopeptidases/antagonists & inhibitors , Cholinesterases/metabolism , Diterpenes/pharmacology , Enzyme Inhibitors/pharmacology , Free Radical Scavengers/pharmacology , Acetylcholinesterase/metabolism , Butyrylcholinesterase/metabolism , Cholinesterase Inhibitors/isolation & purification , Cholinesterase Inhibitors/pharmacology , Diterpenes/isolation & purification , Enzyme Inhibitors/isolation & purification , Free Radical Scavengers/isolation & purification , Free Radicals/chemistry , Nitric Oxide/chemistry , Plant Roots/chemistry
17.
Materials (Basel) ; 12(20)2019 Oct 10.
Article in English | MEDLINE | ID: mdl-31658712

ABSTRACT

Carbon nanotubes (CNTs) have received interest as an attractive reinforcing agent metal matrix composites regarded as an increase to mechanical properties of the final product. Aluminum/carbon nanotubes (Al/CNTs) nanocomposites were observed with different raw material at the optimized experimental condition. In this study, Al-based CNTs composites were three different samples, including un-milled Al, un-milled Al with CNTs, and milled Al with CNTs nanocomposites in the presence of additional CNTs with various experimental conditions while using a traditional ball mill (TBM). The particle morphology and CNT dispersions of milled composites were respectively analysed by scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM), and the mechanical properties of the fabricated composites were tested. In each sample, CNTs were well dispersed on the surface of Al powder at different experimental conditions for milling in a TBM. The Al/CNTs nanocomposites were processed by compacting, sintering and rolling process. The Vickers hardness was used to characterize the mechanical properties. The hardness of Al/CNTs nanocomposites that were fabricated with milled Al with CNT was higher than the reached to in the nanocomposites prepared with the use of un-milled Al with CNT nanocomposites. Therefore, the discrete element method (DEM) simulation was used to complete quantitative analysis. The flow pattern, impact force, and energy at various experimental conditions are considered. The results of the simulations are compared with experimental data.

18.
Chem Biodivers ; 5(9): 1753-61, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18816528

ABSTRACT

Bioassay-guided fractionation of MeOH extract from fenugreek (Trigonella foenum-graecum L.) seeds resulted in the isolation of two rat growth-hormone release stimulators in vitro, fenugreek saponin I (1) and dioscin (9), along with two new, i.e., 2 and 3, and five known analogues, i.e., 4-8. The structures of the new steroidal saponins, fenugreek saponins I, II, and III (1-3, resp.), were determined as gitogenin 3-O-beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranoside, sarsasapogenin 3-O-beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranoside, and gitogenin 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, respectively. Fenugreek saponin I (1) and dioscin (9) caused ca. 12.5- and 17.7-fold stimulation of release, respectively, of rat growth hormone from rat pituitary cells, whereas gitogenin (5) showed moderate activity. To our knowledge, this is the first study to demonstrate that steroidal saponins stimulate rat growth-hormone release in rat pituitary cells.


Subject(s)
Growth Hormone/metabolism , Trigonella/chemistry , Animals , Cells, Cultured , Magnetic Resonance Spectroscopy , Male , Molecular Structure , Pituitary Gland/drug effects , Pituitary Gland/metabolism , Plant Extracts/chemistry , Plant Extracts/pharmacology , Rats , Rats, Sprague-Dawley , Seeds/chemistry
19.
Arch Pharm Res ; 30(6): 691-4, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17679545

ABSTRACT

A new norditerpene alkaloid named 8-O-methylhypaconine (1) was isolated along with twelve known alkaloids from the underground parts of an unknown species of Aconitum plant culti vated in Korea. Among the known alkaloids, two dianthramide glucosides, N-(2'-beta-glucopyra nosyl-5'-hydroxysalicyl)-5-hydroxyanthranilic acid methyl ester (2) and N-(2'-beta-glucopyranosyl-5'-hydroxysalicyl)-5-hydroxy-6-methoxyanthranilic acid methyl ester (3), were isolated from Aconitum plants for the first time. The structures were established on the basis of chemical and spectroscopic methods.


Subject(s)
Aconitum/chemistry , Alkaloids/chemistry , Diterpenes/chemistry , Alkaloids/isolation & purification , Diterpenes/isolation & purification , Korea , Magnetic Resonance Spectroscopy , Spectrometry, Mass, Electrospray Ionization , Spectrophotometry, Infrared
20.
Arch Pharm Res ; 40(9): 1087-1093, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28852980

ABSTRACT

Platycodon grandiflorum root is a traditional medicine and food material rich in triterpenoid saponins. Its major constituent, platycodin D (PD), is known to have various pharmacological properties, but processing methods may influence the PD content. In this study, a fully validated HPLC-ELSD method was developed for the quantification of PD in various states of 73 P. grandiflorum root samples from East Asia, and it exhibited a marked variation of the content. Furthermore, the effects of processing procedures such as peeling and drying temperature on the PD content were investigated using UPLC-ELSD analysis, and as a result, a significant influence of processing methods such as peeling and heating of samples on the content was confirmed. Specifically, unpeeled samples that were dried at 40 °C showed the greatest PD content. The obtained results could facilitate the reliable standardization of P. grandiflorum for precise authentication and efficacious applications.


Subject(s)
Chromatography, High Pressure Liquid/methods , Platycodon/chemistry , Saponins/isolation & purification , Triterpenes/isolation & purification , Asia, Eastern , Plant Roots , Saponins/chemistry , Temperature , Triterpenes/chemistry
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