Search results for "LIX"
showing 10 items of 891 documents
Measuring personal networks and their relationship with scientific production
2011
24 p., 2 figures, 5 tables, 1 appendix and references
Asiakasuskollisuuden muodostuminen jäsenyyteen perustuvien palvelujen kontekstissa : Case SatsElixia
2016
Tutkimuksen tavoitteena oli tutkia liikuntakeskus SatsElixian asiakkaiden kokeman arvon vaikutusta asiakastyytyväisyyteen. Lisäksi haluttiin selvittää tyytyväisyyden ja uskollisuuden välistä suhdetta testaamalla sitä koettujen vaihtokustannusten sekä vaihtoehtoisten palveluntarjoajien houkuttelevuuden mediaatiovaikutusten kautta. Vaikka aiempia tutkimuksia asiakkaiden kokemasta arvosta sekä tyytyväisyyden ja uskollisuuden välisestä suhteesta löytyi paljon, oli kuitenkin mielekästä tutkia käsitteiden välisiä suhteita juuri jäsenyyteen perustuvien palvelujen kontekstissa testaamalla niiden lujuutta vaihtokustannusten ja vaihtoehtoisten palveluntarjoajien mediaatiovaikutuksilla. Teoriaosuudess…
LANGMUIR-SCHAEFER FILMS OF A NEW CALIX[4]PYRROLE-BASED MACROCYCLE EXHIBITING INDUCED CHIRALITY UPON DIFFERENTIATED BINDING WITH CHIRAL ALCOHOL VAPOURS
2004
Narrow rim CMPO/adamantylcalix[4]arenes for the extraction of lanthanides and actinides
2011
Abstract Six p-(1-adamantyl)calix[4]arenes 7, 8 with four differently attached diphenyl-carbamoylmethylphosphine oxide (CMPO) functions at the narrow rim were synthesized. This series was extended by adamantylcalix[4]arenes with two CMPO and two ester, acid or (diethylphosphono)acetylamino groups. Structures of new compounds were proved by NMR, mass-spectrometry and a single-crystal X-ray analysis for the intermediate di-phthalimide 103. The extraction studies towards selected lanthanides and thorium showed that the ligands 7 surpassed the corresponding p-H, p-tert-butyl and p-tert-octyl analogues 3–5 in lanthanide extraction while thorium was extracted with the same or lesser extent. For t…
tert-Butyl-calix[4]arenes Substituted at the Narrow Rim with Cobalt Bis(dicarbollide)(1–) and CMPO Groups – New and Efficient Extractants for Lanthan…
2007
Calix[4]arene derivatives bearing two residues A(–) derived from cobalt bis(dicarbollide)(1–) (1) and two CMPO groups B at their narrow rim were synthesized from tBu-calix[4]arene in four steps. The first step involved the preparation of tBu-calix[4]arene diether derivatives with appropriate precursors for amino groups (mostly nitriles 3). These were O-alkylated through ring-opening reactions with the zwitterionic dioxane derivative [(8-O(CH2CH2)2O-1,2-C2B9H10)-(1′,2′-C2B9H11)-3,3′-Co]0 (10) to produce ionic nitrile derivatives 4. Reduction of the nitrile groups with BH3·SMe2 (or deprotection in the case of the corresponding phthalimido or Boc derivatives 8) led to a series of diamines 5a–f…
Lanthanide complexation with CMPO and CMPO-calix[4]arenes in solution: spectrophotometric and electrospray mass spectrometric approaches.
2007
The binding of lanthanide(III) cations with organophosphorous ligands like CMPO and related calix[4]arene-based derivatives have been investigated using two experimental methods. The stability constants of the lanthanum, europium and ytterbium complexes were first determined in methanol by UV absorption spectrophotometry in the presence of nitrate or chloride anions. The results showed that the stoichiometry and the stability of the complexes formed depend on the position of the CMPO moieties either on the wide or the narrow rim of the calixarene scaffold, the nature of the medium, the conformational mobility of the ligands. Complexation of lanthanum was also followed by ESI-mass spectromet…
Tetra-CMPO-derivatives of calix[4]arenes fixed in the 1,3-alternate conformation
2010
Calix[4]arene derivatives fixed in the 1,3-alternate conformation and substituted at one side by four carbamoylmethylphosphine oxide (CMPO) residues were synthesised. Two CMPO groups are directly attached to the wide rim, while the second pair is bound to the narrow rim via a tri- or tetramethylene spacer. Similar compounds, in which two CMPO groups at the wide rim are combined with two picolinamide groups or two ionisable carboxylic groups at the narrow rim, were also prepared. Some of these calixarene derivatives were studied as extractants for lanthanides (La3+, Eu3+, Yb3+) and thorium (Th4+) from acidic solution into methylene chloride. For selected samples, stability constants in metha…
Conformationally Mobile Wide Rim Carbamoylmethylphosphine Oxide (CMPO)-Calixarenes
1999
Six new calix[4]arene derivatives 2a–f have been synthesised, bearing CMPO-like functions (-NH–C(O)–CH2–P(O)Ph2) at their wide rim. They differ by their alkoxy groups at the narrow rim, comprising all possible combinations of methoxy and syn-propoxy groups including the conformationally mobile tetramethyl ether 2e and the tetrapropyl ether 2f fixed in the cone conformation. Their extraction behaviour for thorium(IV) and several lanthanides(III) from 1M HNO3 to dichloromethane has been studied and compared also to non cyclic calixarene analogues 6a–e. Surprisingly the best extraction results were found for the 1,2-dimethoxy-3,4-dipropoxy derivative 2c among the calixarenes and for the tetram…
Complexation of M3+Lanthanide Cations by Calix[4]arene-CMPO Ligands: A Molecular Dynamics Study in Methanol Solution and at a Water/Chloroform Interf…
2000
Abstract We report a molecular dynamics study on the 1:1 M3+ lanthanide (La3+, Eu3+ and Yb3+) inclusion complexes of an important extractant molecule L: a calix[4]arene-tetraalkyl ether substituted at the wide rim by four NH-C(O)-CH2-P(O)Ph2 arms. The M(NO3)3 and MCl3 complexes of L are compared in methanol solution and at a water / chloroform interface. In the different environments the coordination sphere of M3+ involves the four phosphoryl oxygens and three to four loosely bound carbonyl oxygens of the CMPO-like arms. Based on free energy simulations, we address the question of ion binding selectivity in pure liquid phases and at the liquid-liquid interface where L and the complexes are …
Augstskolas un industrijas sadarbība studentu inovāciju veicināšanai: Latvijas Universitātes gadījuma izpēte
2017
Darbā tiek pētīta augstskolas un industrijas sadarbība inovāciju veicināšanai Eiropas Savienības inovāciju politikas kontekstā. Darba mērķis ir izpētīt augstskolas un industrijas sadarbības veidus, studentu iesaisti sadarbībā, kā arī šo sadarbību ietekmējošos faktorus Latvijas Universitātē. Tika konstatēts, ka Latvijas Universitātes sadarbības ar industriju un studentu iesaistes prakses ir dažādas, un tās atšķiras no fakultātes uz fakultāti. Studentu pētniecisko sadarbību ar industriju, kas ietver inovatīvu risinājumu izstrādi, veicina, galvenokārt, attiecīgās fakultātes mācībspēku sadarbība ar industriju, kā arī iespēja studentam par attiecīgo pētniecības tēmu izstrādāt noslēguma darbu. Pē…