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61.
An optical biosensor consisting of a chromoionophore (ETH5294) (CM) doped sol-gel film interfaced with another sol-gel film immobilized with acetylcholinesterase (AChE) was employed to detect the insecticide dichlorvos. The main advantage of this optical biosensor is the use of a sol-gel layer with immobilized CM that possesses lipophilic property. The highly lipophilic nature of the CM and its compatibility with the sol-gel matrix has prevented leaching, which is frequently a problem in optical sensor construction based on pH indicator dyes. The immobilization of the indicator and enzyme was simple and need no chemical modification. The CM layer is pH sensitive and detects the pH changes of the acetylcholine chloride (AChCl) substrate when hydrolyzed by AChE layer deposited above. In the absence of the AChE layer, the pH response of the CM layer is linear from pH 6 to 8 (R2 = 0.98, n = 3) and it showed no leaching of the lipophilic chromoionophore. When the AChE layer is deposited on top, the optical biosensor responds to AChCl with a linear dynamic range of 40-90 mM AChCl (R2 = 0.984, n = 6). The response time of the biosensor is 12 min. Based on the optimum incubation time of 15 min, a linear calibration curve of dichlorvos against the percentage inhibition of AChE was obtained from 0.5 to 7 mg/L of dichlorvos (17-85% inhibition, R2 = 0.991, n = 9). The detection limit for dichlorvos was 0.5 mg/L. The results of the analysis of 1.7-6.0 mg/L of dichlorvos using this optical biosensor agreed well with a gas chromatography-mass spectrometry detection method. 相似文献
62.
Figueredo G Chalchat JC Chalard P Ozcan MM Al Juhaimi FY 《Natural product research》2012,26(19):1852-1856
The essential oils of sage leaves (Salvia aucheri Bentham var. canescens Boiss. & Heldr.), growing wild in South Anatolia, were extracted by hydrodistillation and analysed by GC and GC-MS. The percentage yields of the essential oils from sage leaves harvested at different years were 1.0%, 1.3%, 1.3%, 1.0%, 1.4%, 1.5% and 1.2%, respectively. In this study, 1,8-cineole, camphre, camphene α-pinene and β-pinene were identified as the major components of sage leaves collected at different periods. The main constituents of sage oil collected over the years were 1,8-cineole (35.01-48.06%), camphre (13.58-23.92%), camphene (6.77-8.82%), α-pinene (5.79-8.54%) and β-pinene (4.32-6.28%). 相似文献
63.
Abdollahi A Hassani A Ghosta Y Bernousi I Meshkatalsadat MH Shabani R Ziaee SM 《Natural product research》2012,26(1):77-83
The effects of postharvest spraying of essential oils from sweet basil (Ocimum basilicum), fennel (Foeniculum vulgare), summer savory (Satureja hortensis) and thyme (Thymus vulgaris) on fungal decay and quality parameters of the 'Thompson seedless' table grape stored at 0?±?1°C for 60 days were evaluated. Results showed that the essential oils, especially of thyme and fennel, have a good inhibitory effect on the development of fungal decay in Thompson table grapes. In addition, essential oils reduced weight loss, berry and rachis browning and had no considerable adverse effect on the flavour of the fruits. GC-MS analysis showed that the main compounds identified in sweet basil, fennel, summer savory and thyme oils are linalool (65.25%), trans-anethole (64.72%), carvacrol (54.14%) and β-ocimene (12.62%), respectively. Therefore, these essential oils have good potential for use as an alternative to synthetic fungicides for the preservation and storage of table grapes. 相似文献
64.
The aerial parts of Euphorbia cornigera Boiss., on extraction with MeOH, yielded new bio-active constituents (1, 2) and known compounds (3 and 4) after MTT cytotoxicity assay-guided fractionation and chromatographic separation were conducted. From the aerial parts of E. cornigera Boiss., new bio-active constituents were extracted in methanol. The extract was partitioned in different organic solvents and the ethylacetate-soluble portion was subjected to Craig's distribution. The MTT cytotoxicity assay-guided chromatographic separation yielded four (1-4), out of which two (1, 2) were new and two known (3, 4) bio-active compounds, and they are reported for the first time from this source. Their structure and relative stereochemistry were established by analysing spectroscopic and mass measurement data. The isolates were named as: 13-O-[(2Z ,4 E ,6 Z)]-deca-2,4,6-trienoylingenol (1), 13-O-( 2 Z ,4 E ,6 Z)-deca-2,4,6-trienoyl-20-O-angeloylingenol (2), 13-O-dodecanoyl-20-O-hexanoylingenol (3) and 3-O-(2,3-dimethylbutanoyl)-13-O-dodecanoyl-20-O-hexadecanoylingenol (4). Literature revealed that compounds 1 and 2 are new metabolites, while 3 and 4 are known, and are reported for the first time from this source. Cytotoxicities of isolates were evaluated in terms of IC(50) against RAW and HT-29 cell lines through MTT assay using ambrucin hydrochloride as a control. Compound 3 showed more activity than control, while 1, 2 and 4 were moderate. 相似文献
65.
Shongwe MS Al-Rahbi SH Al-Azani MA Al-Muharbi AA Al-Mjeni F Matoga D Gismelseed A Al-Omari IA Yousif A Adams H Morris MJ Mikuriya M 《Dalton transactions (Cambridge, England : 2003)》2012,41(8):2500-2514
The two potentially tridentate and monoprotic Schiff bases acetylpyridine benzoylhydrazone (HL(1)) and acetylpyridine 4-tert-butylbenzoylhydrazone (HL(2)) demonstrate remarkable coordination versatility towards iron on account of their propensity to undergo tautomeric transformations as imposed by the metal centre. Each of the pyridyl aroylhydrazone ligands complexes with the ferrous or ferric ion under strictly controlled reaction conditions to afford three six-coordinate mononuclear compounds [Fe(II)(HL)(2)](ClO(4))(2), [Fe(II)L(2)] and [Fe(III)L(2)]ClO(4) (HL = HL(1) or HL(2)) displaying distinct colours congruent with their intense CT visible absorptions. The synthetic manoeuvres rely crucially on the stoichiometry of the reactants, the basicities of the reaction mixtures and the choice of solvent. Electrochemically, each of these iron compounds exhibits a reversible metal-centred redox process. By all appearances, [Fe(III)(L(1))(2)]ClO(4) is one of only two examples of a crystallographically elucidated iron(III) bis-chelate compound of a pyridyl aroylhydrazone. Several pertinent physical measurements have established that each of the Schiff bases stabilises multiple spin states of iron; the enolate form of these ligands exhibits greater field strength than does the corresponding neutral keto tautomer. To the best of our knowledge, [Fe(III)(L(1))(2)]ClO(4) and [Fe(III)(L(2))(2)]ClO(4) are the first examples of ferric spin crossovers of aroylhydrazones. Whereas in the former the spin crossover (SCO) is an intricate gradual process, in the latter the (6)A(1)?(2)T(2) transition curve is sigmoidal with T(?)~280 K and the SCO is virtually complete. As regards [Fe(III)(L(1))(2)]ClO(4), M?ssbauer and EPR spectroscopic techniques have revealed remarkable dependence of the spin transition on sample type and extent of solvation. In frozen MeOH solution at liquid nitrogen temperature, both iron(III) compounds exist wholly in the doublet ground state. 相似文献
66.
M. Musa Saad H.-E. 《Solid State Communications》2012,152(14):1230-1233
The electronic and magnetic properties of new ordered vanadium-based double perovskite oxides Ba2VTO6 (T=Nb and Mo) have been investigated using the ab-initio linear muffin-tin orbitals method with the atomic-sphere approximation (LMTO-ASA). The calculations performed by using the local spin-density approximation with on-site Coulomb interaction (LSDA+U) style. The self-consistent band structure calculations predict half-metallic ferromagnetic (HM-FM) ground states with total spin magnetic moments of 2.1021 μB and 3.0633 μB per formula unit cell for Ba2VNbO6 and Ba2VMoO6, respectively. HM-FM nature in two compounds organizes from the ddpπ-superexchange interactions 3d-t2g2–O (2p)–4d-t2gn (n=0 or 1), conformity with Zener–Goodenough–Kanamori rules. 相似文献
67.
MS Shongwe UA Al-Zaabi F Al-Mjeni CS Eribal E Sinn IA Al-Omari HH Hamdeh D Matoga H Adams MJ Morris AL Rheingold E Bill DJ Sellmyer 《Inorganic chemistry》2012,51(15):8241-8253
Several potentially tridentate pyridyl and phenolic Schiff bases (apRen and HhapRen, respectively) were derived from the condensation reactions of 2-acetylpyridine (ap) and 2'-hydroxyacetophenone (Hhap), respectively, with N-R-ethylenediamine (RNHCH(2)CH(2)NH(2), Ren; R = H, Me or Et) and complexed in situ with iron(II) or iron(III), as dictated by the nature of the ligand donor set, to generate the six-coordinate iron compounds [Fe(II)(apRen)(2)]X(2) (R = H, Me; X(-) = ClO(4)(-), BPh(4)(-), PF(6)(-)) and [Fe(III)(hapRen)(2)]X (R = Me, Et; X(-) = ClO(4)(-), BPh(4)(-)). Single-crystal X-ray analyses of [Fe(II)(apRen)(2)](ClO(4))(2) (R = H, Me) revealed a pseudo-octahedral geometry about the ferrous ion with the Fe(II)-N bond distances (1.896-2.041 ?) pointing to the (1)A(1) (d(π)(6)) ground state; the existence of this spin state was corroborated by magnetic susceptibility measurements and M?ssbauer spectroscopy. In contrast, the X-ray structure of the phenolate complex [Fe(III)(hapMen)(2)]ClO(4), determined at 100 K, demonstrated stabilization of the ferric state; the compression of the coordinate bonds at the metal center is in accord with the (2)T(2) (d(π)(5)) ground state. Magnetic susceptibility measurements along with EPR and M?ssbauer spectroscopic techniques have shown that the iron(III) complexes are spin-crossover (SCO) materials. The spin transition within the [Fe(III)N(4)O(2)](+) chromophore was modulated with alkyl substituents to afford two-step and one-step (6)A(1) ? (2)T(2) transformations in [Fe(III)(hapMen)(2)]ClO(4) and [Fe(III)(hapEen)(2)]ClO(4), respectively. Previously, none of the X-salRen- and X-sal(2)trien-based ferric spin-crossover compounds exhibited a stepwise transition. The optical spectra of the LS iron(II) and SCO iron(III) complexes display intense d(π) → p(π)* and p(π) → d(π) CT visible absorptions, respectively, which account for the spectacular color differences. All the complexes are redox-active; as expected, the one-electron oxidative process in the divalent compounds occurs at higher redox potentials than does the reverse process in the trivalent compounds. The cyclic voltammograms of the latter compounds reveal irreversible electrochemical generation of the phenoxyl radical. Finally, the H(2)salen-type quadridentate ketimine H(2)hapen complexed with an equivalent amount of iron(III) to afford the μ-oxo-monobridged dinuclear complex [{Fe(III)(hapen)}(2)(μ-O)] exhibiting a distorted square-pyramidal geometry at the metal centers and considerable antiferromagnetic coupling of spins (J ≈ -99 cm(-1)). 相似文献
68.
Bandar Ali Al-Asbahi Mohamad S. AlSalhi Mohammad Hafizuddin Hj. Jumali Amanullah Fatehmulla Saif M. H. Qaid Wafa Musa Mujamammi Hamid M. Ghaithan 《Molecules (Basel, Switzerland)》2022,27(20)
The improvement of optical and optoelectronic properties of the individual poly [2-methoxy-5- (2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly[2-methoxy-5-(3,7-dimethyl-octyloxy)-1,4-phenylenevinylene]–End capped with Dimethyl phenyl (OC1C10–PPV–DMP), and poly (9,9′-di- n -octylfluorenyl-2,7-diyl) (F8) was revealed by blending them in ternary hybrid with optimal ratio (F8/2 wt.% MEH-PPV/2 wt.% OC1C10–PPV–DMP). All individual and optimal ternary solutions were prepared via the solution-blending method followed by depositing them onto glass and ITO substrates using spin-coating technique. The semi-crystalline phase of the ternary hybrid and the strong mixing between the conjugated polymers were evidenced by observing the X-ray diffraction patterns that related to F8 into the hybrid diffractogram. The optical and optoelectronic properties of all prepared thin films were investigated in terms of absorption and emission spectra, Commission International d′Eclairage (CIE) coordinates, and current–voltage (I-V) characterizations. Emission peaks at the entire range of visible spectrum can be revealed from the ternary hybrid of the three individual conjugated polymers, producing white emission as evidenced from the emission spectrum and CIE coordinates of the hybrid. Among all fabricated organic light-emitting diodes (OLEDs) devices, the ternary hybrid-based-OLED revealed the best performance in terms of current and turn-on voltage. 相似文献
69.
Shabani Mohammad Reza Moosavian Mohammad Ali Royaee Sayed Javid Zamani Yahya 《Catalysis Surveys from Asia》2022,26(1):46-57
Catalysis Surveys from Asia - An acid gas stream was utilized instead of pure H2S as feedstock in the methanol thiolation reaction with Alkali/W/γ-Al2O3 catalysts. The catalysts were... 相似文献
70.
A method for obtaining a medium pressure (p ~ 1 torr), low power (< 100 W), RF-generated plasma jet, suitable for chemical kinetics studies and technological applications is described. Though various supply gases can be used to create the plasma jet, only results on the properties of a nitrogen jet are given in this paper with an emphasis on some spectral and electrical characteristics. The emission spectra of the nitrogen jet are discussed and spatial distributions of the relative concentration of nitrogen or radical impurities emitting species such as N2(C3Πu, v' = 0), NH(A3Πg, v'=0) in the bulk of the postdischarge plasma are calculated from the intensity of their vibrational bands. Electrical space resolved double probe measurements and the spatial distributions of the electron density and temperature in the plasma jet are also presented. Possible applications are shortly discussed. 相似文献