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  • 1
    Language: English
    In: Organic letters, 20 January 2012, Vol.14(2), pp.513-5
    Description: The concomitant addition of the histone deacetylase inhibitor and the DNA methyltransferase inhibitor to the culture medium of an entomopathogenic fungus, Isaria tenuipes, greatly enhanced its secondary metabolite production and led to the isolation of tenuipyrone (1), a novel polyketide with an unprecedented tetracyclic ring system bearing a spiroketal structural component, along with two known C(10)-polyketides, cephalosporolide B (2), which is a plausible biosynthetic precursor of 1, and cephalosporolide F (3).
    Keywords: Hypocreales -- Chemistry ; Pyrones -- Chemistry ; Spiro Compounds -- Chemistry
    ISSN: 15237060
    E-ISSN: 1523-7052
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  • 2
    Language: English
    In: Tetrahedron Letters, 2012, Vol.53(3), pp.277-280
    Description: A new aromatic polyketide glycoside, indigotide A ( ), was isolated from the culture broth of the entomopathogenic fungus, , along with known cyclic depsipeptides, destruxins A, A , B, B and E ( – ), and a polyketide, NG-393 ( ). Repeated treatment of the . culture broth with 5-azacytidine, a DNA methyltransferase inhibitor, led to the isolation of another new aromatic polyketide glycoside, indigotide ( ).
    Keywords: Entomopathogenic Fungi ; Secondary Metabolites ; Polyketides ; DNA Methyltransferase Inhibitor ; Epigenetics ; Chemistry
    ISSN: 0040-4039
    E-ISSN: 1873-3581
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  • 3
    Language: English
    In: Journal of Pragmatics, 2011, Vol.43(4), pp.1127-1147
    Description: This study investigates the interlanguage behavior of Chinese learners of American English, focusing on how they offer ‘compliments’ in a second language (L2). In this paper, the behavior of Taiwanese ESL (English-as-a-second-language) learners in the United States is compared with that of Taiwanese native speakers of Mandarin Chinese and with that of native speakers of American English, in order to reveal how the ESL learners perform this speech act in naturally occurring contexts. The results showed that the linguistic strategies and options employed to realize compliments by native Chinese speakers were very different from those used by native speakers of English. For example, Chinese speakers were much less inclined to offer compliments than were English speakers. This tendency was also visible in the L2 of Chinese ESL speakers. Therefore, although there were some similarities between the learners and the target language speakers, the performance of the former, in terms of the use of strategies, positive semantic carriers, syntactic formulaic patterns, supportive moves and/or small talk, could often be seen to reflect native language (L1) communicative styles and the transfer of L1 socio-cultural strategies into L2 behavior.
    Keywords: Interlanguage Pragmatics ; Cross-Cultural Pragmatics ; Sociolinguistic Competence ; Naturally Occurring Data ; Speech Acts ; Compliments ; Computer Science ; Languages & Literatures
    ISSN: 0378-2166
    E-ISSN: 1879-1387
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  • 4
    Language: English
    In: Tetrahedron, 22 July 2012, Vol.68(29), pp.5817-5823
    Description: The concomitant addition of a histone deacetylase inhibitor, suberoyl bis-hydroxamic acid, and a DNA methyltransferase inhibitor, RG-108, to the culture medium of , an entomopathogenic fungus, induced a significant increase in diversity of secondary metabolites. From the culture media were isolated two new highly oxidized ergosterols, formosterols A ( ) and B ( ), and five new isariotin analogs, 12′- -acetylisariotin A ( ), 1- -isariotin A ( ), and isariotins K–M ( – ), together with 22,23-epoxy-3,12,14,16-tetrahydroxyergosta-5,7-dien-11-one (named formosterol C) ( ), isariotins A ( ), C ( ), and E ( ), TK-57-164A ( ), and beauvericin ( ). The NMR spectra, X-ray single crystallographic diffraction, and chemical transformations revealed the structures of the two new formosterols and five new isariotins. The stereochemistry of formosterol C ( ) was deduced from its spectroscopic data. The side chains of formosterols A–C ( – ) contained -22,23-epoxide, which is rarely present in naturally occurring sterols and triterpenes.
    Keywords: Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 5
    Language: English
    In: Tetrahedron Letters, 18 September 2013, Vol.54(38), pp.5162-5166
    Description: 1,5-Diphenylpent-3-en-1-yne derivatives were isolated in minor quantities from terrestrial plants and exhibited strong anti-inflammatory activity. A cross coupling reaction between -benzyl-9-BBN and chloroenynes under mild condition was developed resulting in the formation of different 1,5-diphenylpent-3-en-1-yne derivatives with a full control on the / selectivity. Several substrates bearing electron-donating and electron-withdrawing substituents were tolerable under the reaction conditions affording the corresponding products in good yields. This is the first study to report the synthesis of a vast array of novel 1,5-diphenylpent-3-en-1-yne derivatives paving the way for the preparation of tailored derivatives on mass scale necessary for biological studies and drug development.
    Keywords: Henna ; Palladium ; B-Benzyl-9-Bbn ; B-Alkyl Suzuki Coupling ; Aqueous Reaction ; Chemistry
    ISSN: 0040-4039
    E-ISSN: 1873-3581
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  • 6
    Language: English
    In: European Journal of Organic Chemistry, August 2012, Vol.2012(24), pp.4533-4540
    Description: An efficient method for the synthesis of flavones and γ‐benzopyranones has been developed utilizing a mild Sonogashira coupling and 18‐crown‐6 ether mediated 6‐ cyclization of ‐alkynoylphenyl acetates. By using this strategy, flavones and γ‐benzopyranones bearing electron‐donating groups, halogens, and simple alkyl substituents were synthesized in satisfactory yields. A facile, mild, and selective method for the synthesis of flavones and γ‐benzopyranones is reported. ‐Alkynoylphenyl acetates were obtained from either acyl chloride derivatives or substituted salicylates. Upon removing the acetate group, flavones and γ‐benzopyranones were synthesized within 15 min with the aid of 18‐crown‐6 ether. A library of flavones and γ‐benzopyranones was established.
    Keywords: Synthetic Methods ; Oxygen Heterocycles ; Cross‐Coupling ; Cyclization ; Michael Addition
    ISSN: 1434-193X
    E-ISSN: 1099-0690
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  • 7
    Language: English
    In: Journal of agricultural and food chemistry, 14 September 2011, Vol.59(17), pp.9219-25
    Description: Recycling agricultural resources has become an important issue worldwide promoting the economical value of agricultural production processes. Desugared sugar cane extract (DSE) from Saccharum officinarum is a byproduct obtained during sugar production. Two new neolignan glucosides, saccharnan A (1) and saccharnan B (2), together with 10 known phenolics (3-12) were isolated from DSE, and their structures were elucidated on the basis of NMR spectral analysis. Compounds 3, 4, 8, and 9 showed good activity against DPPH radical (IC(50) ≤ 51.20 μM) and compounds 3-8 and 12 exhibited strong ABTS(+) free radical scavenging activity (IC(50) ≤ 51.57 μM) compared to those of the positive controls, ascorbic acid and Trolox. Moreover, compounds 7 and 12 acted as potent tyrosinase inhibitors (IC(50) ≤ 42.59 μM) compared to the positive control arbutin. Our results highlighted the economical value of recycling DSE for the future development of natural antioxidants and/or tyrosinase inhibitors.
    Keywords: Antioxidants -- Analysis ; Enzyme Inhibitors -- Analysis ; Monophenol Monooxygenase -- Antagonists & Inhibitors ; Plant Extracts -- Chemistry ; Saccharum -- Chemistry
    ISSN: 00218561
    E-ISSN: 1520-5118
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  • 8
    Language: English
    In: European Journal of Organic Chemistry, December 2012, Vol.2012(34), pp.6760-6766
    Description: Copper catalysed oxidative coupling reaction of formamides with β‐keto esters and 2‐carbonyl‐substituted phenols successfully proceeded through direct C–H bond activation of formamides. The corresponding carbamates were formed with high stereoselectivity under mild reaction conditions. This protocol was successfully applied to the synthesis of three novel halogenated carbamates and a carbaryl insecticide derivative. Our results suggest the use of 6.0 equiv. TBHP is crucial for this type of reaction. Synthesis of carbamates was accomplished through the reaction of β‐keto esters or 2‐carbonyl‐substituted phenols with formamides using copper chloride and an oxidant. Sixteen aliphatic as well as fourteen aromatic carbamates were prepared in good to excellent yields. The methodology was applied to the synthesis of halogenated carbamates and a carbaryl insecticide derivative.
    Keywords: Synthetic Methods ; Oxidation ; C–H Activation ; Regioselectivity ; Carb­amates ; Copper
    ISSN: 1434-193X
    E-ISSN: 1099-0690
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  • 9
    Language: English
    In: Bioorganic & Medicinal Chemistry, 01 July 2013, Vol.21(13), pp.3866-3872
    Description: The addition of a DNA methyltransferase inhibitor, 5-azacytidine, to fungus culture broth changed its secondary metabolites profile. Analysis of the culture broth extract led to the isolation of three new bisabolane-type sesquiterpenoids: (7 )-(+)-7- -methylsydonol ( ), (7 ,11 )-(+)-12-hydroxysydonic acid ( ) and 7-deoxy-7,14-didehydrosydonol ( ), along with eight known compounds. The isolated compounds were evaluated for their anti-diabetic and anti-inflammatory activities. Among the isolates, ( )-(+)-sydonol ( ) did not only potentiate insulin-stimulated glucose consumption but also prevented lipid accumulation in 3T3-L1 adipocytes. Additionally, ( )-(+)-sydonol ( ) exhibited significant anti-inflammatory activity through inhibiting superoxide anion generation and elastase release by fMLP/CB-induced human neutrophils. This is the first report on isolating a secondary metabolite with anti-diabetic and anti-inflammatory activities from microorganisms.
    Keywords: Epigenetic ; Aspergillus Sydowii ; Bisabolane-Type ; Anti-Diabetic ; Anti-Inflammatory ; Medicine ; Chemistry ; Anatomy & Physiology
    ISSN: 0968-0896
    E-ISSN: 1464-3391
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  • 10
    In: International Journal of Sociotechnology and Knowledge Development (IJSKD), 2012, Vol.4(4), pp.44-57
    Description: This study aims to provide an effective approach to reduce the turnover rate and forecast the supply of hair stylists for the hair salon industry. An absorbing Markov chain process was applied in this study to forecast the supply of hair stylists for a hair salon chain. A hair salon chain with 13 salons in Taiwan was investigated as the case in this study. According to its business goals and expansion plans, and considering the firm’s present personnel profiles, the authors estimate the future demand for stylists and reduce the turnover rate for this company. In addition, this study finds that, based on a promotion system, the average turnover rate for hairdressing apprentices decreases from 19.500% to 17.770%, and the training period could be shortened from three years to one year and 11 months. Finally, they also found that the estimated supply of hair salon workers at each hierarchy level from 2010 to 2014 will be insufficient. The findings in this study could provide insights for the human resources department of hair salon industry.
    Keywords: Absorbing Markov Chain; Hair Salon Industry; Hairdressing; Promotion System; Turnover Rate
    ISSN: 1941-6253
    E-ISSN: 19416261
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