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21.
Nizakat Bib Misal Khan Amal Badshah Muhammad Ashraf Chaudry 《Radiation Physics and Chemistry》2005,73(6):362-364
Minimally processed cauliflower samples were irradiated, stored at 5 °C for 2 weeks and analyzed for sensory, physicochemical and microbiological qualities at 0th, 7th and 14th days. The data showed highest mean values of 7.93 and 7.57 for appearance and flavor, respectively, for 1.0 kGy treated samples. The D10 values of contaminating microorganisms on cauliflower were 0.20 (Escherischia coli) and 0.24 kGy (Salmonella paratyphae A.) and the resulting 5D10 value was 1.2 kGy. The study revealed that a dose of 1.5 kGy is enough for retention of quality and reduction of microbial load to 5D10 values in cauliflower during 2 weeks storage at refrigerated temperature. 相似文献
22.
The reactions of ten main group acidic oxides and oxyanions with molten alkali metal carbonate eutectics have been studied by thermogravimetry. Products have been identified by IR and Raman spectroscopy and stoichiometries suggested for the several reactions as oxide is progressively incorporated. Ultimately the tetrahedral ortho-oxyanion was formed except with the less acidic oxides (As2O3, Sb2O3, SiO2). Sulphite was partially oxidised by the carbon dioxide atmosphere to sulphate. 相似文献
23.
Saira Shahzadi Moazzam H. Bhatti Khadija Shahid Saqib Ali Saadia R. Tariq Mohammad Mazhar Khalid M. Khan 《Monatshefte für Chemie / Chemical Monthly》2002,133(8):1089-1096
Summary. Tributyltin(IV) derivatives of six different pharmaceutically active carboxylates were synthesized. The complexes were characterized
by different analytical techniques (elemental analysis; infrared, NMR, and mass spectroscopy). 119Sn NMR data were also recorded in six different coordinating and non-coordinating solvents. The antibacterial activities of
the compounds were tested using ten different bacteria relative to the reference drugs ampicillin and cephalexin.
Received September 20, 2001. Accepted (revised) December 6, 2001 相似文献
24.
Ahmad VU Khan A Farooq U Kousar F Khan SS Nawaz SA Abbasi MA Choudhary MI 《Chemical & pharmaceutical bulletin》2005,53(4):378-381
Three new tricyclic cis-clerodane type diterpenoids trivially named as limbatolide A (1), limbatolide B (2) and limbatolide C (3) have been isolated from the roots of Otostegia limbata along with two known compounds; oleanic acid and beta-sitosterol. The structure elucidation of the new compounds was based primarily on two-dimensional (2D) NMR techniques. Compounds 1-3 displayed inhibitory potential in a concentration-dependent manner against acetylcholinesterase (AChE; EC 3.1.1.7) and butyrylcholinesterase (BChE; EC 3.1.1.8) enzymes, respectively. 相似文献
25.
Tahir AA Molloy KC Mazhar M Kociok-Köhn G Hamid M Dastgir S 《Inorganic chemistry》2005,44(25):9207-9212
Ba(dmae)2 (dmaeH=N,N-dimethylaminoethanol, C4H11NO) reacts with Co(acac)2 (acac=2,4-pentanedionate) to produce the trinuclear coordination complex [Ba2Co(acac)4(dmae)3(dmaeH)] in an 85% yield. Spectroscopic and single-crystal X-ray diffraction experiments indicate that the complex possesses a structure in which two barium atoms and a cobalt atom are bridged by acac and dmae groups. The barium centers are eight and nine coordinate with BaO7N and BaO7N2 coordination spheres while the cobalt is a more regular CoO5N octahedron. This 2:1 heterobimetallic molecular complex was investigated as precursor for the deposition of thin film by AACVD. The film was characterized by SEM and XRD. TGA shows that the complex starts thermal decomposition upon heating in nitrogen atmosphere at 105 degrees C to produce barium cobalt oxide material of a Ba2CoO3 composition with an orthorhombic structure. The synthetic approach detailed here represents a unique route to the formation of a heterobimetallic barium cobalt coordination complex. 相似文献
26.
Ahmad VU Zubair M Athar Abbasi M Abid Rashid M Rasool N Nahar Khan S Iqbal Choudhary M Kousar F 《Magnetic resonance in chemistry : MRC》2005,43(6):486-488
The investigation of the chemical constituents of Symplocos racemosa Roxb led to the isolation of two new glycosides, symcomoside A (1) and symcomoside B (2), together with one known glycoside, tortoside C (3), which is reported for the first time from this plant. The structures of the new compounds were determined by 1D and 2D homonuclear and heteronuclear NMR spectroscopy, from chemical evidence and by comparison with published data for closely related compounds. Symcomoside B (2) showed potent inhibitory activity against alpha-glucosidase in a concentration-dependent fashion with an IC50 value of 0.733 +/- 0.033 mM whereas symcomoside A (1) showed very weak inhibitory activity against alpha-glucosidase (9.90% in 0.70 mM). 相似文献
27.
Marine brown alga Dictyota dichotoma (Dictyotaceae) collected from Karachi coast of Arabian Sea yielded two new (1 and 2) enones (dolastane-diterpenoids) named: dichotenone-A and -B along with an olide (loliolide, 3) as a new source. Their structures have been characterized with the aid of 2D-NMR spectroscopic techniques. 相似文献
28.
Khan KM Shujaat S Rahat S Hayat S Atta-ur-Rahman Choudhary MI 《Chemical & pharmaceutical bulletin》2002,50(11):1443-1446
Eight new beta-N-substituted acyl hydrazides along with their corresponding acyl derivatives were synthesized and screened for in vitro beta-glucuronidase inhibition and found to be active against the enzyme. All of these compounds were found to be noncompetitive inhibitors except for N'-(2-cyanoethyl)-4-hydroxy benzohydrazide (10), which was found to be an uncompetitive inhibitor. Structure-activity relationship studies indicated that the benzyloxy group present in compounds 12 and 13 is responsible for the beta-glucuronidase inhibition activity. 相似文献
29.
The reactions of lanthanum(III), cerium(III), praseodymium(III) and europium(III) chlorides have been studied in the molten lithium nitrate-potassium nitrate and sodium nitrate-potassium nitrate eutectics. The ultimate reaction products have been shown to be oxides (La2O3, CeO2, Pr6O11 and Eu2O3, respectively) which increased the rate of decomposition of the melts, while in three cases an intermediate oxide nitrate was formed (LaONO3, PrONO3 and EuONO3). The temperatures and stoichiometries of the reactions have been established. 相似文献
30.
Muhammad WT Fox KF Fox A Cotham W Walla M 《Rapid communications in mass spectrometry : RCM》2002,16(24):2278-2285
Single nucleotide polymorphisms (SNPs) and mutations were genotyped for both homozygous and heterozygous PCR products of p53, a tumor suppressor gene, and K-ras, an oncogene, using electrospray ionization (ESI) quadrupole time-of-flight (Q-TOF) mass spectrometry (MS) and ESI-quadrupole MS analysis. Mass accuracy was adequate for both instruments to detect genetic changes in homozygous PCR products, including the most difficult to distinguish (adenine [A] --> thymine [T] transversion). However, for the detection of A --> T shifts (9.0 Da difference) in heterozygous PCR products, the increased resolution of ESI-Q-TOFMS proved essential. Although, greater mass differences in heterozygotes (e.g. cytosine [C] <--> T or guanine [G] <--> A) can be discriminated using ESI-quadrupole MS analysis. 相似文献