• Title/Summary/Keyword: Cyclic compound

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Effects of Schisandra chinensis fruit extract and gomisin A on the contractility of penile corpus cavernosum smooth muscle: a potential mechanism through the nitric oxide - cyclic guanosine monophosphate pathway

  • Choi, Bo Ram;Kim, Hye Kyung;Park, Jong Kwan
    • Nutrition Research and Practice
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    • v.12 no.4
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    • pp.291-297
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    • 2018
  • BACKGROUND/OBJECTIVES: This study evaluated the effects and molecular mechanisms of the Schisandra chinensis fruit extract (SC) and its major compound gomisin A (GA), on the contractility of rabbit penile corpus cavernosum smooth muscle (PCCSM). MATERIALS/METHODS: PCCSM was exposed to SC or GA after appropriate pretreatment with nitric oxide synthase (NOS) blocker, guanylate cyclase blocker, adenylyl cyclase blocker or protein kinase A blocker. Subsequently, we evaluated the cyclic nucleotide in the perfusate by radioimmunoassay, protein expression level of neuronal NOS (nNOS) and endothelial NOS (eNOS) by western blot, and the interaction of SC or GA with udenafil and rolipram. RESULTS: Both SC and GA induce PCCSM relaxations in a concentration-dependent manner. Pretreatment with NOS blocker, guanylate cyclase blocker, adenylyl cyclase blocker or protein kinase A blocker result in significantly decreased relaxation. SC and GA also induce the levels of cyclic nucleotide in the perfusate in a concentration-dependent manner. Perfusion with GA also showed significantly higher levels of eNOS protein. Furthermore, the udenafil and rolipram induced relaxations of PCCSM were enhanced after exposure to SC and GA. Our results indicate that SC and GA induce the relaxation of PCCSM via the nitric oxide (NO)-cGMP and cAMP signaling pathways. CONCLUSIONS: The SC and GA are potential alternative treatments for men who want to consume natural products to ameliorate erectile function, or who do not respond to the commercially available medicines.

Strength upgrading of steel storage rack frames in the down-aisle direction

  • El Kadi, Bassel;Cosgun, Cumhur;Mangir, Atakan;Kiymaz, Guven
    • Steel and Composite Structures
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    • v.23 no.2
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    • pp.143-152
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    • 2017
  • This paper focuses on the seismic performance of pallet-type steel storage rack structures in their down aisle direction. As evidenced by experimental research, the seismic response of storage racks in the down-aisle direction is strongly affected by the nonlinear moment-rotation response of the beam-to-column connections. In their down-aisle direction, rack structures are designed to resist lateral seismic loads with typical moment frames utilizing proprietary beam-to-column moment-resisting connections. These connections are mostly boltless hooked type connections and they exhibit significantly large rotations resulting in large lateral frame displacements when subjected to strong ground motions. In this paper, typical hooked boltless beam-to-column connections are studied experimentally to obtain their non-linear reversed cyclic moment-rotation response. Additionally, a compound type connection involving the standard hooks and additional bolts were also tested under similar conditions. The simple introduction of the additional bolts within the hooked connection is considered to be a practical way of structural upgrade in the connection. The experimentally evaluated characteristics of the connections are compared in terms of some important performance indicators such as maximum moment and rotation capacity, change in stiffness and accumulated energy levels within the cyclic loading protocol. Finally, the obtained characteristics were used to carry out seismic performance assessment of rack frames incorporating the tested beam-to-column connections. The assessment involves a displacement based approach that utilizes a simple analytical model that captures the seismic behavior of racks in their down-aisle direction. The results of the study indicate that the proposed method of upgrading appears to be a very practical and effective way of increasing the seismic performance of hooked connections and hence the rack frames in their down-aisle direction.

The Incredible Shrinking Noun Phrase: Ongoing Change in Japanese Word Formation

  • Kevin Heffernan;Yusuke Imanishi
    • Asia Pacific Journal of Corpus Research
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    • v.4 no.1
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    • pp.1-23
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    • 2023
  • The Japanese language, as a typical agglutinating language, permits large noun phrases (NP) containing ten or more morphemes. In this paper, we argue that the nature of the NP in Japanese is changing. Our data are drawn from the Balanced Corpus of Contemporary Written Japanese. We conduct a series of apparent-time studies of ongoing changes in complex NPs. We first examine the length of compound nouns, followed by the usage of bound suffixes. We then examine ongoing changes in complex NPs that contain genitive case markers. Finally, we examine noun incorporation. All of our studies show a trend towards shorter, less complex NPs. Furthermore, our results suggest that the usage rate of phrases that modify the noun inside the NP (compound nouns, bound nouns, NPs containing genitive case, noun incorporation) appears to be decreasing over time. On the other hand, the usage rate of modifying material outside of the NP (positional phrases, relative clauses) appears to be increasing over time. We conclude by suggesting that our results reflect a diachronic change of decreasing synthetic morphology and increasing analytic morphology. We end by pointing out the implications of this work on our understanding syntheticity and analyticity.

Improving Joint Reliability of Lead-free Solder on Flexible Substrate under Cyclic Bending by Adding Graphene Oxide Powder (그래핀 산화 분말을 첨가한 플렉시블 기판 솔더 접합부의 반복 굽힘 신뢰성 향상)

  • Ko, Yong-Ho;Yu, Dong-Yurl;Son, Junhyuk;Bang, Junghwan;Kim, Taek-Soo
    • Journal of the Microelectronics and Packaging Society
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    • v.26 no.3
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    • pp.43-49
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    • 2019
  • In this study, a new approach using graphene oxide (GO) powder-composited Sn-3.0Ag-0.5Cu(in wt.%) solder paste for improving the bending reliability of solder joints between a flexible substrate and small outline package (SOP) was suggested. The GO addition slightly affected the melting temperature, however, the change in the melting temperature was not significant. Meanwhile, we observed the addition of GO could suppress IMC growth and IMC thickness of solder joint during the reflow process. Moreover, the cyclic bending test was also performed for evaluation of reliability in solder joint and we could improve the cyclic bending reliability of solder joint by adding GO powders. For 0.2 wt.% of GO added to the solder joint, the bending lifetime was increased to 20% greater than that without GO. Pull strength and ductility of the solder joint with GO were also higher than those of the joint without GO and it was assumed that this effect by adding GO could contribute to improve cyclic bending reliability of solder joint.

The Spreading Characteristics of the (Polymer/18-Crown-6) Composite Solution for Water Cast-Membranes ((Polymer/18-Crown-6)복합박막 제조용액의 수면전개 특성)

  • 남석태;최호상;최성부;김병식
    • Membrane Journal
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    • v.6 no.4
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    • pp.265-272
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    • 1996
  • The (polymer/carrier) composite membranes for separating the metallic ion have been prepared by the water cast-method. The morphology of these membranes was affected by the physical properties of the spreading solution. The surface tension of the (polymer/18-crown-6) composite solution was decreased with increasing the concentration of 18-crown-6 compound and the surface tension of polymer solution decreased the following order PVC>PS>CA. The viscosity of CA solution decreased with increasing the contents of the 18-crown-6 compound, but PVC and PS solutions showed no significance changes according as the concentration of 18-crown-6 compound. In the composite solutions, the spreading ability was improved by' the cyclic 18-crown-6 molecules which acted as an electric buffer and diminished the intermolecular force between the polymer chains. The (polymer/18-crown-6) composite membrane was more uniform than that of the mono polymer membrane on the coagulation state of polymer, and the top and bottom sides of membrane showed also the more smooth structure according as the concentration increment of 18-crown-6 molecule.

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Nonlinear P-Δ analysis of steel frames with semi-rigid connections

  • Valipour, Hamid R.;Bradford, Mark A.
    • Steel and Composite Structures
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    • v.14 no.1
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    • pp.1-20
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    • 2013
  • This paper presents the formulation for a novel force-based 1-D compound-element that captures both material and second order P-${\Delta}$ nonlinearities in steel frames. At the nodal points, the element is attached to nonlinear rotational and a translational springs which represent the flexural and axial stiffness of the connections respectively. By decomposing the total strain in the material as well as the generalised displacements of the flexible connections to their elastic and inelastic components, a secant solution strategy based on a direct iterative scheme is introduced and the corresponding solution strategy is outlined. The strain and slope of the deformed element are assumed to be small; however the equilibrium equations are satisfied for the deformed element taking account of P-${\Delta}$ effects. The formulation accuracy and efficiency is verified by some numerical examples on the nonlinear static, cyclic and dynamic analysis of steel frames.

Behavior of FRP bonded to steel under freeze thaw cycles

  • Toufigh, Vahab;Toufigh, Vahid;Saadatmanesh, Hamid
    • Steel and Composite Structures
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    • v.14 no.1
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    • pp.41-55
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    • 2013
  • Fiber reinforced polymers (FRP) materials are increasingly being used for strengthening and repair of steel structures. An issue that concerns engineers in steel members which are retrofitted with FRP is stress experienced due to temperature changes. The changing temperature affects the interface bond between the FRP and Steel. This research focused on the effects of cyclical thermal loadings on the interface properties of FRP bounded to steel members. Over fifty tests were conducted to investigate the thermal effects on bonding between FRP and steel, which were cycled from temperature of $-11^{\circ}C$ ($12^{\circ}F$) to $60^{\circ}C$ ($140^{\circ}F$) for 21-36 days. This investigation consisted of two test protocols, 1) the tensile test of epoxy resin, tack coat, FRP and FRP-steel plate, 2) tensile test of each FRP compound and FRP with steel after going through thermal cyclic loading. This investigation reveals an extensive reduction in the composite's strength.

High sensitivity biosensor for mycotoxin detection based on conducting polymer supported electrochemically polymerized biopolymers

  • Dhayal, Marshal;Park, Gye-Choon;Park, Kyung-Hee;Gu, Hal-Bon
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.243.1-243.1
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    • 2010
  • Devices based on nanomaterials platforms are emerging as a powerful tool for ultrasensitive sensors for the direct detection of biological and chemical species. In this talk, we will report the preparation and the full characterization of electrochemical polymerization of biopolymers platforms and nano-structure formation for electrochemical detection of enzymatic activity and toxic compound in electrolyte for biosensor applications. Formation of an electroactive polymer film of two different compounds has been quantified by observing new redox peak at higher potentials in cyclic voltammogram measurements. RCT value of at various biopolymer concentration based hybrid films has been obtained from electrochemical impedance spectroscopy analysis and possible mechanism for formation of complexes during electrochemical polymerization on conducting substrates has been investigated. Biosensors developed based on these hybrid biopolymers have very high sensitivity.

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Voltammetric Studies of Cu-Adriblastina Complex and its Effect on ssDNA-Adriblastina Interaction at In Situ Mercury Film Electrode

  • D.Abd El Hady;M.Ibrahim Abdel Hamid;M.Mahmoud Sellem;N.Abo E Maali
    • Archives of Pharmacal Research
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    • v.27 no.11
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    • pp.1161-1167
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    • 2004
  • Adriblastina, a cancerostatic anthracycline antibiotic, causes considerable oxidative damage to DNA molecules. The interaction of this compound with DNA was investigated using Osteryoung square wave stripping voltammetry (OSWSV) and cyclic voltammetry (CV) at an in situ mercury film electrode. It was found that the equilibrium constant of the bonded oxidized form of the drug was 63 times bigger more important than that of the bonded reduced form. Copper forms 1 metal: 2 drug stoichiometry complex which is highly stable compared to ssDNA-drug interaction and consequently inhibited the drug biochemical damaging effects. Copper complex offered sub-nanogram determination of adriblastina in aqueous and urine media.

Preparation of New Polyenaminonitriles Containing Cyclic and Methylene Units and Their Thermal Properties

  • Cho, Jeong-Hyun;Gong, Myoung-Seon
    • Macromolecular Research
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    • v.8 no.5
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    • pp.209-214
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    • 2000
  • Polyenaminonitriles containing cycloaliphatic and aliphatic units were prepared by interfacial or solution polymerization reaction of p-bis(1-chloro-2,2-dicyanovinyl) benzene (1) with 4-aminobenzyl-amine, 1-(2-aminoethyl)piperazine, 2-(aminomethyl)pyrrolidine and 4-(aminomethyl)piperidine. The chemical structure of the polymers was confirmed through a syntheses of the model compound. The resulting polymers possessed inherent viscosities of 0.29∼0.62 dL/g and they were easily soluble in polar aprotic solvents and common organic solvents. Thermal properties of the polymers such as curability and stability were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and infrared spectroscopy. The polymers exhibited a large exotherm in DSC analyses and underwent a curing reaction around 340-370$\^{C}$ to form insoluble materials. The polymers showed 70-80% residual weight at 600 $\^{C}$ under nitrogen.

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