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111.
An extracellular cholesterol oxidase (cho) enzyme was isolated from the Streptomyces parvus, a new source and purified 18-fold by ion exchange and gel filtration chromatography. Specific activity of the purified enzyme was found to be 20 U/mg with a 55 kDa molecular mass. The enzyme was stable at pH 7.2 and 50 °C. The enzyme activity was inhibited in the presence of Pb(2+), Ag(2+), Hg(2+), and Zn(2+) and enhanced in the presence of Mn(2+). The enzyme activity was inhibited by the thiol-reducing reagents (DTT, β-mercaptoethanol), suggesting that disulfide linkage is essential for the enzyme activity. The enzyme activity was found to be maximum in the presence of Triton X-100 and X-114 detergents whereas sodium dodecyl sulfate fully inactivated the enzyme. The enzyme showed moderate stability towards all organic solvents except acetone, benzene, chloroform and the activity increased in the presence of isopropanol and ethanol. The K(m) value for the oxidation of cholesterol by this enzyme was 0.02 mM. 相似文献
112.
Bhalla V Roopa Gupta A Dhir A Kumar M 《Dalton transactions (Cambridge, England : 2003)》2011,40(19):5176-5179
A new pentaquinone-based chemosensor armed with phenolic moieties has been synthesized. The fluorescence behaviour of the chemosensor in the presence of different chemical inputs mimics the functions of a digital encoder. 相似文献
113.
Dr. Vandana Bhalla Varun Vij Abhimanew Dhir Dr. Manoj Kumar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(12):3765-3772
New hetero‐oligophenylene derivative ( 2 ) was synthesized which exhibits aggregation‐induced emission enhancement (AIEE) in H2O/THF (80:20). The aggregates serve as a biological probe for three different proteins, that is bovine serum albumin (BSA), cytochrome c, and lysozyme, and DNA in contrasting modes. Further, among 29 metal ions tested, the contrasting fluorescence behavior of aggregates of 2 is observed with only Pb2+ and Pd2+ ions. Multiple output logic circuits based upon the fluorescence behavior between BSA and cytochrome c and between Pb2+ and Pd2+ ions are constructed. 相似文献
114.
A novel ditopic fluorescent chemosensor 2, based on the 1,3-alternate conformation of thiacalix[4]crown possessing two complexation sites, was synthesized and shows ratiometric nanomolar detection of Cu(2+) ions and exhibits negative allosteric behaviour between Cu(2+)/Li(+) ions in mixed aqueous media. 相似文献
115.
Novel pentacenequinone derivative 3 has been synthesized using the Suzuki-Miyaura coupling protocol which forms fluorescent nanoaggregates in aqueous media due to its aggregation-induced emission enhancement attributes and selectively senses picric acid with a detection limit of 500 ppb. 相似文献
116.
The problem of reflection and transmission due to longitudinal and transverse waves incident obliquely at a plane interface between uniform elastic solid half-space and fractional order thermoelastic solid half-space has been studied. It is found that the amplitude ratios of various reflected and refracted waves are functions of angle of incidence and frequency of incident wave and are influenced by the fractional order thermoelastic properties of media. The expressions of amplitude ratios and energy ratios have been computed numerically for a particular model. The variation of amplitude and energy ratios with angle of incidence is shown graphically. The conservation of energy at the interface is verified. 相似文献
117.
The impact of sustained inhaled corticosteroid (ICS) therapy on the larynx and pharynx was assessed using a prospective, cross-sectional, and investigator-blinded study conducted at the University Hospital Aintree, Liverpool, UK. Forty-six adults recruited from two local general practices and from general ENT clinics at our University hospital were investigated for the study. Patients were allocated to three groups according to ICS use. Laryngeal effects were measured by correlating the results of a vocal performance questionnaire, a respiratory symptom questionnaire, and measurements obtained by computerized speech analysis. Sustained vowels and connected speech were analyzed in normal and asthmatic subjects. Acoustic analysis was correlated with cellular markers of inflammation after biopsy. Regular ICS users had significantly more pharyngeal inflammation and throat discomfort (P < 0.0001). Vocal performance was also worse in this group (P < 0.0001). They were more likely to have hoarseness, weakness of voice, aphonia, sore throat, throat irritation, and cough (P < 0.0001). All these variables were directly related to one another (P < 0.0001). Multiple linear regression analysis showed that jitter was a good objective measure of hoarseness (P < 0.05). Regular ICS users were significantly more likely to have abnormal jitter, shimmer, and closed-phase quotient scores (P < 0.0001). There was no difference between the groups in the observed parameters of inflammation (P > 0.01). A higher pharyngitis score did not correlate with any of the histological markers of inflammation (P > 0.01). Local side effects are more common in asthmatics that use ICS regularly. Measures of laryngeal function are significantly worse in regular ICS users. However, histological markers and oropharyngeal redness are not reliable measures of inflammation. 相似文献
118.
119.
The carbosilanes RMe2Si(CH2)xSiH3, [R = 2-Th (1a, 2a), 4-Me-2-Th (3a, 4a), 2-Fu (5a, 6a), 5-Me-2-Fu (7a, 8a); x = 2 and 3], with primary SiH3 end groups undergo a facile dehydropolymerization under ambient conditions (50 °C, 48 h) in presence of Cp2TiCl2/2.2 n-BuLi catalyst to afford the corresponding poly(hydrosilane)s 1–8 bearing carbosilyl side chains appended with thienyl/furyl groups. These have been characterized by GPC, IR, multinuclear (1H, 13C{1H}, 29Si{1H}) NMR, UV and PL spectral studies. 相似文献
120.
Tripathi V Tabor SL Mantica PF Utsuno Y Bender P Cook J Hoffman CR Lee S Otsuka T Pereira J Perry M Pepper K Pinter JS Stoker J Volya A Weisshaar D 《Physical review letters》2008,101(14):142504
The beta decay of 33Mg (N=21) presented in this Letter reveals intruder configurations in both the parent and the daughter nucleus. The lowest excited states in the N=20 daughter nucleus, 33Al, are found to have nearly 2p-2h intruder configuration, thus extending the "island of inversion" beyond Mg. The allowed direct beta-decay branch to the 5/2{+} ground state of the daughter nucleus 33Al implies positive parity for the ground state of the parent 33Mg, contrary to an earlier suggestion of negative parity from a g-factor measurement. An admixture of 1p-1h and 3p-3h configurations is proposed for the ground state of 33Mg to explain all of the experimental observables. 相似文献