Spinel Cu0.5Zn0.5Fe2O4 ferrite doped with different rare earth ions is investigated. FT-IR was used to investigate the effect of different rare earth substitution on the magnetic properties of this system. It was found that when Fe3+ is replaced with La and Nd ions, almost no changes were observed in the band position of IR spectra. As Gd and Dy substituted, small shifts for the band spectra were detected. On the other hand when Sm is replacing Fe3+ a noticed increase in the frequency band position was observed. The observed increase in the band ν1 position for Sm substitution can be explained as the replace of Fe3+ ions with Sm3+ ions in the tetrahedral site (A-site) of the spinel.

Thin filmsofZn40Se60 were preparedbythevacuumthermalevaporationtechnique.Theinfluenceof annealedtemperatureonthestructuralandopticalpropertieswasinvestigatedusingtheX-ray diffraction(XRD),scanningelectronmicroscopy(SEM)andopticaltransmission.TheXRDstudiesshow that theas-depositedfilmisamorphousinnature,butthecrystallinityimprovedwithincreasingthe annealingtemperature.Furthermoretheparticlesizeandcrystallinityincreasedwhereasthedisloca- tion andstrainsdecreasedwithincreasingtheannealingtemperature.SEMstudiesshowedthatthe annealingtemperatureinducedchangesinthemorphologyoftheas-depositedsample.Variousoptical constanthavebeencalculatedforas-depositedandannealedfilms.Themechanismoftheoptical absorptionfollowstheruleofdirecttransition.Itwasfoundthat,theopticalenergygap(Eg) decreased with increasingtheannealingtemperature.TheseresultscanbeinterpretedbytheDavisandMotte model. Ontheotherhandthemaximumvalueoftherefractiveindex(n) isshiftedtowardthelong wavelengthbyincreasingtheannealingtemperature.

Thin filmsofZn40Se60 were preparedbythevacuumthermalevaporationtechnique.Theinfluenceof annealedtemperatureonthestructuralandopticalpropertieswasinvestigatedusingtheX-ray diffraction(XRD),scanningelectronmicroscopy(SEM)andopticaltransmission.TheXRDstudiesshow that theas-depositedfilmisamorphousinnature,butthecrystallinityimprovedwithincreasingthe annealingtemperature.Furthermoretheparticlesizeandcrystallinityincreasedwhereasthedisloca- tion andstrainsdecreasedwithincreasingtheannealingtemperature.SEMstudiesshowedthatthe annealingtemperatureinducedchangesinthemorphologyoftheas-depositedsample.Variousoptical constanthavebeencalculatedforas-depositedandannealedfilms.Themechanismoftheoptical absorptionfollowstheruleofdirecttransition.Itwasfoundthat,theopticalenergygap(Eg) decreased with increasingtheannealingtemperature.TheseresultscanbeinterpretedbytheDavisandMotte model. Ontheotherhandthemaximumvalueoftherefractiveindex(n) isshiftedtowardthelong wavelengthbyincreasingtheannealingtemperature.

Thin filmsofZn40Se60 were preparedbythevacuumthermalevaporationtechnique.Theinfluenceof annealedtemperatureonthestructuralandopticalpropertieswasinvestigatedusingtheX-ray diffraction(XRD),scanningelectronmicroscopy(SEM)andopticaltransmission.TheXRDstudiesshow that theas-depositedfilmisamorphousinnature,butthecrystallinityimprovedwithincreasingthe annealingtemperature.Furthermoretheparticlesizeandcrystallinityincreasedwhereasthedisloca- tion andstrainsdecreasedwithincreasingtheannealingtemperature.SEMstudiesshowedthatthe annealingtemperatureinducedchangesinthemorphologyoftheas-depositedsample.Variousoptical constanthavebeencalculatedforas-depositedandannealedfilms.Themechanismoftheoptical absorptionfollowstheruleofdirecttransition.Itwasfoundthat,theopticalenergygap(Eg) decreased with increasingtheannealingtemperature.TheseresultscanbeinterpretedbytheDavisandMotte model. Ontheotherhandthemaximumvalueoftherefractiveindex(n) isshiftedtowardthelong wavelengthbyincreasingtheannealingtemperature.

multistep reactions using chemical and photochemical methods. Some of the synthesized photochromic dihydroindolizine derivatives were substituted on the fluorene (region A) and pyridazine (region C) moieties in order to provide the appropriate functionality for optimal tuning of the photochromic properties of the system. Irradiation of the photochromic DHIs with polychromatic light led to ring opened colored betaines, which underwent thermal 1,5-electrocyclization. The red to green colored betaines produced after UV irradiation returned back through 1,5-electrocyclization to the corresponding DHIs with different rate constants depending on the substituents in both fluorene and pyridazine regions. The kinetic measurements of the thermal 1,5-electrocyclization under different temperatures that ranged from
10 to 25 C showed that the half-lives of the colored betaines fall in the second to hours domain. Interestingly, these materials showed a very good photochromic behavior not only in solution but also in the PMMA matrix. Irradiation of a slide prepared by the deep-coating method led to the formation of the colored betaine and the kinetics of the thermally reversible 1,5- electrocyclization and the AFM image of the film has been recorded. Indeed, the chemical and thermal stability of the investigated betaines in polymer (PMMA) will render such species useful for a plethora of new of applications.

multistep reactions using chemical and photochemical methods. Some of the synthesized photochromic dihydroindolizine derivatives were substituted on the fluorene (region A) and pyridazine (region C) moieties in order to provide the appropriate functionality for optimal tuning of the photochromic properties of the system. Irradiation of the photochromic DHIs with polychromatic light led to ring opened colored betaines, which underwent thermal 1,5-electrocyclization. The red to green colored betaines produced after UV irradiation returned back through 1,5-electrocyclization to the corresponding DHIs with different rate constants depending on the substituents in both fluorene and pyridazine regions. The kinetic measurements of the thermal 1,5-electrocyclization under different temperatures that ranged from
10 to 25 C showed that the half-lives of the colored betaines fall in the second to hours domain. Interestingly, these materials showed a very good photochromic behavior not only in solution but also in the PMMA matrix. Irradiation of a slide prepared by the deep-coating method led to the formation of the colored betaine and the kinetics of the thermally reversible 1,5- electrocyclization and the AFM image of the film has been recorded. Indeed, the chemical and thermal stability of the investigated betaines in polymer (PMMA) will render such species useful for a plethora of new of applications.

The presentstudyinvestigatedthehormonesconcentrationsandgonadsalterationsof Clarias gariepinus caused bysublethelconcentrationsof4-nonylphenol(0,0.05,0.08and0.1mg/l).The changesintheactivitiesofthehormonesafterexposuretothesesubletheldosesof4-nonylpenol referredtoendocrinedisruptionin Clariasgariepinus in associationwithhistopathologicalchangesin reproductivetissues.Thelevelsofthyroidstimulatinghormone(TSH),triiodothyronine(T3),total thyroxine(T4),folliclestimulatinghormone(FSH),luteinizinghormone(LH)andtestosterone concentrationssignificantlydecreased(Po0.05) inthetreatedfishincomparisonwithcontrol.17-bestradiolincreasedsignificantly( Po0.05) with4-nonylphenolconcentrationsincrease.Reductionin the gonadosomaticindexwasevidentwithincreaseofsublethaldosesof4-nonylphenol.The histopathologicalchangesofNP-treatedwererecordedingonadsof Clariasgariepinus reflectingtheir sensitivitytoNP-estrogeniclikeeffects.

The presentstudyinvestigatedthehormonesconcentrationsandgonadsalterationsof Clarias gariepinus caused bysublethelconcentrationsof4-nonylphenol(0,0.05,0.08and0.1mg/l).The changesintheactivitiesofthehormonesafterexposuretothesesubletheldosesof4-nonylpenol referredtoendocrinedisruptionin Clariasgariepinus in associationwithhistopathologicalchangesin reproductivetissues.Thelevelsofthyroidstimulatinghormone(TSH),triiodothyronine(T3),total thyroxine(T4),folliclestimulatinghormone(FSH),luteinizinghormone(LH)andtestosterone concentrationssignificantlydecreased(Po0.05) inthetreatedfishincomparisonwithcontrol.17-bestradiolincreasedsignificantly( Po0.05) with4-nonylphenolconcentrationsincrease.Reductionin the gonadosomaticindexwasevidentwithincreaseofsublethaldosesof4-nonylphenol.The histopathologicalchangesofNP-treatedwererecordedingonadsof Clariasgariepinus reflectingtheir sensitivitytoNP-estrogeniclikeeffects.

The presentstudyinvestigatedthehormonesconcentrationsandgonadsalterationsof Clarias gariepinus caused bysublethelconcentrationsof4-nonylphenol(0,0.05,0.08and0.1mg/l).The changesintheactivitiesofthehormonesafterexposuretothesesubletheldosesof4-nonylpenol referredtoendocrinedisruptionin Clariasgariepinus in associationwithhistopathologicalchangesin reproductivetissues.Thelevelsofthyroidstimulatinghormone(TSH),triiodothyronine(T3),total thyroxine(T4),folliclestimulatinghormone(FSH),luteinizinghormone(LH)andtestosterone concentrationssignificantlydecreased(Po0.05) inthetreatedfishincomparisonwithcontrol.17-bestradiolincreasedsignificantly( Po0.05) with4-nonylphenolconcentrationsincrease.Reductionin the gonadosomaticindexwasevidentwithincreaseofsublethaldosesof4-nonylphenol.The histopathologicalchangesofNP-treatedwererecordedingonadsof Clariasgariepinus reflectingtheir sensitivitytoNP-estrogeniclikeeffects.

5-Chloro-3-methyl-1-phenyl-1-pyrazole-carboxaldehyde(1 ) was reacted with hydrazine hydrate and thiosemicarbazide to afford the corresponding hydrazones 2 and thiosemicarbazones 4. The latter compounds were used to obtain the pyrazole derivatives 3, 5-7. A series of azines 8a-e were obtained by reacting 2 with aromatic aldehydes. Potassium permanganate oxidation of1 gave the acid 9, which was transformed into the corresponding acid azide 11 then used to prepare diverse urea derivatives 13-18 via Curtius reaction