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السجلات المعروضة 41 -- 60 من 539
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Biochemical And Environmental Studies On Hepatoma Patients In Egypt
( Qatar University , 1994 , Article)The present study was carried out on 102 hepatoma patients collected mainly from the National Cancer Institute, Cairo University, during the period 1988-1991 . Environmental and personal data were collected for each patient. ... -
REMOTE MONITORING AND CONTROL OF MICROCOMPUTER RAISED DATA ACQUISITION SYSTEMS
( Blackwell Publishing Ltd , 1994 , Article) -
A New Poly (Vinyl Chloride) Matrix Membrane Electrode for Manual and Flow Injection Determination of Pilocarpine in Some Pharmaceutical Preparations
( Taylor and Francis Inc. , 1994 , Article)A novel pilocarpinium ion selective membrane electrode is prepared, characterized and used in pharmaceutical analysis. The electrode system incorporates a PVC membrane with pilocarpine-reineckatc ion pair complex as an ... -
Flow injection potentiometric determination of harmine and harmaline hallucinogens
( Wiley-VCH Verlag , 1995 , Article)Flow injection analysis (FIA) systems incorporating potentiometric sensors for harmine and harmaline hallucinogens are described. The sensors are based on the use of harmine and harmaline tetraphenylborate or reineckate ... -
Constituents of plants growing in Qatar: part xxviii. Constituents Of cistanche phelypaea
( Qatar University , 1995 , Article)Ten compounds were isolated from the methanolic extract of the aerial parts of Cistanche phelypaea (Orobanchaceae) and identified as echinacoside (1), tubuloside A (2), tubuloside E (3), acteoside (4), 2'-acetylacteoside ... -
Constituents of Plants Growing in Qatar, Part XXX: A New Iridoid from Cistanche Phelypaea (L) COUT
(1995 , Article)New iridoid named phelypaeside (1) was isolated from the dried aerial parts of Cistanche phelypae (Orobanchaceae) growing in Qatar -
Constituents of Plants Growing in Qatar, Part XXVI: Phytochemical investigation of Rumex vesicarius
(1995 , Article)The study of Rumex vesicarius revealed the isolation and identification of four anthraquinones (chrysoplanol (I), emodin (II), physcion (III) and rhein (IV) and seven flavonoids (apigenin (V), isoorientin (VI), isovitesin ... -
Major sterol composition of some algae from Qatar
( Elsevier Science Ltd. , 1995 , Article)Thirteen macroscopic algae belonging to the three main divisions Chlorophyceae, Rhodophyceae and Phaeophyceae from the coast of Qatar (Arabian Gulf) were investigated for their sterol composition by using GC-MS coupling ... -
Solid-State Ac-Conductivity Analysis For The Long Debated Catalytic Activity Of The Boralite Sieve
( Qatar University , 1996 , Article)The ac-phase dependent impedance, capacitance and dielectric loss of boralite are measured and correlated with those of a similar history HZSM-5 as a function of frequency (0.1-100 kHz) and temperature (373-638 K) at 0.8 ... -
Kinetic Determination of Morphine in Illicit Powders, Using a Fluoride Selective Electrode, Based on Reaction with 1-Fluoro-2,4-dinitrobenzene
( Springer New York , 1996 , Article)A simple, accurate and selective method is described for the determination of morphine in illicit powders, based on monitoring the initial rate of fluoride ion liberation from the reaction of morphine with 1-fluoro-2,4-d ... -
Ac-conductivity analysis of the effects of partial dealumination and γ-irradiation on the electric features of HZSM-5
( Elsevier , 1996 , Article)For illustrating such titled effects, analysis of the electric impedance, capacitance, and dielectric loss dependences on the frequency W (0.1–100 kHz) and temperature T (373–673 K) is correlated at 0.8 V for γ-irradiated ... -
Evidence by ac-conductivity for the higher mobility of boron (over aluminium)-associated Brønsted sites in boron-modified HZSM-5
( Elsevier , 1996 , Article)A correlation ac-conductivity analysis is performed at 102–105 Hz, 373–613 K and 0.8 V for characterizing the effect of increasing boron incorporation in HZSM-5 lattice on altered electric features in BZSM-5 samples of ... -
Guaianolides from Picris radicata
( Elsevier Science Ltd. , 1996 , Article)The methylene chloride-methanol (1:1) extract of the aerial parts of Picris radicata Forssk afforded two new guaianolides. The structures were established from spectral data. -
Ground- and excited-state properties of some 3,4-dihydro-1-(2-p-substituted benzylidene)naphthalenones: substituent and environmental effects
( John Wiley & Sons, Ltd. , 1997 , Article)Electronic absorption and steady-state fluorescence emission of seven 3,4-dihydro-1-(2-p-substituted benzylidene)naphthalenones (1–7) show sizable solvent dependence. The charge-transfer (CT) absorption maxima of these ... -
Optical and electrical properties of a new polymer
( John Wiley & Sons, Inc. , 1997 , Article)Thin film of poly (5-isopropylidenecyclo-1,4-vinylene-2,3-dicarboxylicacidamide-s-methyl hydrazinecarbodithioate) (II) (Scheme 1) of 5 μm thickness was prepared. The dielectric properties of the prepared sample were studied ... -
Determination of glafenine in dosage forms and serum by thin layer densitometry and high performance liquid chromatography
( Elsevier , 1997 , Article)New thin layer densitometry and high performance liquid chromatography (HPLC) methods are described for quantitative determination of glafenine in dosage forms in the presence of its photo-degradation products and in serum ... -
Mercurimetric potentiometric determination of barbiturates using a solid-state iodide ion-selective electrode
( Taylor and Francis Inc. , 1997 , Article)A simple potentiometric method is described for mercurimetric titration of barbiturates using a solid-state iodide ion-selective electrode. The optimum titration conditions involve the use of a borate buffer of pH 9-10 as ... -
Plastic Membrane Electrodes for the Potentiometric Determination of Codeine in Pharmaceutical Preparations
( Springer New York , 1997 , Article)Four PVC membrane electrode systems responsive to codeinium cation are described. These electrodes are based on the use of the ion-association complexes of the codeinium cation with tetraphenylborate and reineckate ... -
Inhibition of the acid corrosion of iron with haloacetic acids
( Scientific Publishers of India , 1997 , Article)The efficiency of chloro, dichloro, trichloro, bromo, and iodoacetic acids as inhibitors for acid corrosion of iron was studied using polarization technique. A significant retardation of the corrosion rate is observed in ... -
(−)-Paniculatol, a new ent-labdane bromoditerpene from Laurencia paniculata
( Elsevier Science Ltd. , 1997 , Article)(−)-Paniculatol, 1, an unusual tricyclic bromoditerpene belonging to the ent-labdane series has been identified in the red alga Laurencia paniculata collected on Qatari coasts, Arabian Gulf. The structure displays an unusual ...