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1.
Moktar Ferid Mahmoud Dogguy Néjia Kbir-Ariguib Melika Trabelsi 《Journal of solid state chemistry》1984,53(2):149-154
The MIPO3Sm(PO3)3(MI = Li, Na, Ag) systems were studied. Differential thermal analysis and X-ray diffraction were used to investigate the liquidus and solidus relations. Three compounds LiSm(PO3)4, NaSm(PO3)4, and AgSm(PO3)4 were obtained which melt incongruently at 1248, 1143, and 1078 K, respectively. These compounds are isomorphous with their homologs LiLn(PO3)4, NaLn(PO3)4, AgLn(PO3)4 (Ln = Ce, La, Nd). They belong to the monoclinic system. The LiSm(PO3)4 unit cell parameters refined by least squares method are a = 16.43(3) Å, b = 7.16(1) Å, c = 9.65(3) Å, β = 125,9°(1), with the space group and Z = 4. NaSm(PO3)4 and AgSm(PO3)4 are isotypic; they cristallize in the space group, Z = 4; their unit cell parameters are, respectively, a = 12.18(1) Å, b = 13.05(1) Å, c = 7.25(5) Å, β = 126,53°(4), , b = 13.06(1) Å, c = 7.201(9) Å, β = 126,57°(7). The ir spectra of the last two compounds indicate that these phosphates are chain phosphates. 相似文献
2.
Chaabouni SE Mechichi T Limam F Marzouki N 《Applied biochemistry and biotechnology》2005,125(2):99-112
Two endoglucanases (EGs), EG A and EG B, were purified to homogeneity from Penicillium occitanis mutant Pol 6 culture medium. The molecular weights of EG A and EG B were 31,000 and 28,000 kDa, respectively. The pI was about 3 for EG A and 7.5 for EG B. Optimal activity was obtained at pH 3.5 for both endoglucanases. Optimal temperature for enzyme activity was 60 degrees C for EG A and 50 degrees C for EG B. EG A was thermostable at 60 degrees C and remained active after 1 h at 70 degrees C. EGs hydrolyzed carboxymethylcellulose, phosphoric acid swollen cellulose, and beta-glucan efficiently, whereas microcrystalline cellulose (Avicel) and laminarin were poorly hydrolyzed. Only EG B showed xylanase activity. Furthermore, these EGs were insensitive to the action of glucose and cellobiose but were inhibited by the divalent cations Hg2+, Co2+, and Mn2+. 相似文献
3.
Ferid Abidi Nayssene Aissaoui Jean-Charles Gaudin Jean-Marc Chobert Thomas Haertlé Mohamed Nejib Marzouki 《Applied biochemistry and biotechnology》2013,170(2):231-247
Prot-2 protease previously purified to homogeneity from Botrytis cinerea showed potentiality to be used in detergency and for production of bioactive peptides. To extend the characterization of Prot-2 protease, antifungal and antibacterial assays were performed in vitro using protein hydrolysates prepared from muscle of mackerel (Scomber scomborus) treated with this enzyme. The most active hydrolysate (degree of hydrolysis of 8 %) exhibited inhibition effect towards bacteria and phytopathogenic fungi, demonstrating that Prot-2 proteolysis generated bioactive peptides. Biochemical and molecular characterization of the purified Prot-2, by SDS-PAGE/Tryptic in gel-digestion and LC-MS/MS analysis, was investigated. The peptide amino acid sequence alignment search in database revealed a moderate homology between the determined amino acid sequence of Prot-2 protease and the known fungal trypsin/chymotrypsin in particular from Glomerella, Metarhizium and Streptomyces. From peptide sequence data obtained by mass spectrometry and sequences homologies, primers were defined and a cDNA fragment of 786 bp was amplified by RT-PCR. The cDNA nucleotide sequence analysis revealed an open reading frame coding for 262 amino acid residues. The deduced amino acid sequence of Prot-2 showed moderate identity with trypsin of Glomerella graminicola (74 %) and with chymotrypsin from Metarhizium anisopliae (71 %). Prot-2 exhibited a Ser protease homology and showed in addition the specific His motif of trypsin/chymotrypsin family. 相似文献
4.
In the framework of systematic investigations in the properties of rare-earth cyclotriphosphates, polycristalline samples of La1−xNdxP3O9·3H2O have been synthesized with x=5×10−3, 10−2, 5×10−2, 10−1 and 1. Absorbance spectra were measured at 300 K in the 300-1000 nm region. Fluorescent emissions from the 4F3/2 multiplet were observed at 300 and 6 K under pulsed laser excitations in either the 4F7/2 or 4F3/2 multiplet and the decays of these emissions were measured. These decays are exponential with decay-times on the order of 100 ns for all values of x. No important lengthening is observed as either the Nd concentration is decreased from 100 to 0.5 at% or the temperature is lowered from 300 to 6 K. These results are in contradiction with those obtained for the anhydrous La1−xNdx(PO3)3 compounds prepared by progressively heating the corresponding La1−xNdxP3O9·3H2O powder materials, a fact which shows the predominant role played by the water molecules in the Nd3+ luminescence in the considered hydrated compounds. 相似文献
5.
6.
The temperature dependences of the permittivity of TlInS2(1 −x)Se2x
solid solutions have been experimentally investigated in the temperature range including the points of structural phase transitions
in the solid solutions. It has been established that the isovalent substitution of selenium for sulfur in the anion sublattice
of the TlInS2(1 − x)Se2x
solid solutions shifts the phase transition temperatures T
i
and T
c
toward the low-temperature range with a simultaneous decrease in the temperature interval of the existence of the incommensurate
phase. The T-x phase diagram is constructed for the solid solutions under study and the coordinates are determined for a critical point
(of the Lifshitz type) at which the lines T
i
(x) and T
c
(x) converge in the phase diagram. The pattern of the T-x phase diagram for the TlInS2(1 − x)Se2x
solid solutions has been analyzed within the phenomenological model of a virtual crystal. 相似文献
7.
Olfa Tabbene Dorra Gharbi Imen Ben Slimene Salem Elkahoui Mohamed Najib Alfeddy Pascal Cosette Maria Luisa Mangoni Thierry Jouenne Ferid Limam 《Applied biochemistry and biotechnology》2012,168(8):2245-2256
In the present study, we evaluated the antioxidant and the scavenging ability of C14, C15 and C16 bacillomycin D-like lipopeptides produced by B38 strain. They all displayed strong reducing power activity, hydroxyl and superoxide anion radicals scavenging activities and inhibition of lipid peroxidation. In addition, they were found to protect plasmid DNA damage from hydroxyl radical oxidation. Data suggested that their antioxidant potency can be attributed to the hydrophobic and aromatic side-chain groups of their amino acids as well as to the aliphatic chain of their beta amino fatty acids. Note that the hydrocarbon chain length did not interfere with the antioxidant power. Overall, such bacillomycin D lipopeptides which exhibit antioxidant and radical scavenging activities may be useful for cosmetic, therapeutic or pharmaceutical purposes in order to delay or prevent oxidative deterioration of manufactured products. 相似文献
8.
9.
M. -H. Yu. Seyidov R. A. Suleymanov F. Salehli S. S. Babayev T. G. Mammadov A. I. Nadjafov G. M. Sharifov 《Physics of the Solid State》2009,51(3):568-576
The experimental data on memory effects in an incommensurate phase are analyzed both in undoped layered TlInS2 crystals selected from different technological batches and in TlInS2: La. Various types of unusual memory effect are detected. It is shown that the observed memory effects are due to pinning
of the soliton superstructure by a defect density wave in the internal field of the electret state.
Original Russian Text ? M.-H. Yu. Seyidov, R.A. Suleymanov, F. Salehli, S.S. Babayev, T.G. Mammadov, A.I. Nadjafov, G.M. Sharifov,
2009, published in Fizika Tverdogo Tela, 2009, Vol. 51, No. 3, pp. 533–542. 相似文献
10.
F. Chehimi-Moumen P. Llewellyn F. Rouquerol G. Vacquier D. Ben Hassen-Chehimi M. Ferid M. Trabelsi-Ayadi 《Journal of Thermal Analysis and Calorimetry》2005,82(3):783-789
Summary The aim of this work is the optimization of the preparation of anhydrous gadolinium hydrogen phosphate with good fluorescence
properties. The products obtained by dehydration of gadolinium hydrogen phosphate trihydrate depend on the conditions chosen
for the thermal treatment. For this reason, the dehydration was followed by Constant Rate Thermal Analysis whilst strictly
controlling the water vapour pressure above the sample. Intermediate samples, obtained during dehydration were characterised
by IR spectroscopy and X-ray diffraction. It has thus been shown that the thermal pathway taken for the dehydration depends
on the water vapour pressure above the sample in the region from 10-2to 5 mbar. Under the lowest water vapour pressure (5·10-3mbar), the elimination of the crystallization water is carried out in a continuous way and produces a quasi-amorphous intermediate.
Under higher water vapour pressure (5 mbar), well crystallized intermediate products are obtained. The results obtained suggest
that the trihydrate contains zeolitic water which confirms a prior structural study. 相似文献