Search results for "kemia"
showing 10 items of 1521 documents
Oppilaiden visuaaliset representaatiot kiehumisessa
2012
Tämän tutkimuksen tarkoituksena oli selvittää, miten visuaalisten representaatioiden käyttö mahdollisesti auttaa kemian oppimisessa. Erityisesti paneuduttiin kemian visuaalisten representaatioiden tuottamisen vaatimiin kognitiivisiin toimintoihin. Suoritettiin kirjallisuustutkimus kemian visuaalisista representaatioista ja niiden käytöstä oppimisessa. Kirjallisuustutkimuksen tulosten perusteella visuaalisten representaatioiden tuottamista tulisi hyödyntää osana kemian opetusta, sillä se vaatii oppijalta monipuolisia ja syvällisiä kognitiivisia prosesseja sekä auttaa oppijaa visualisoimaan kemiallisen tiedon submikroskooppisen tason tapahtumia. Juuri molekyylitason ymmärtäminen on kemian opi…
The Missing Member of the Partially O-Alkylated Resorcinarene Family: Synthesis and Conformation of Methyl Tetramethoxy Resorcinarene
2013
An improved Lewis acid catalyzed synthesis method for methyl tetramethoxy resorcinarene is described, which produced the missing lower rim methyl derivative of this partially O-alkylated resorcinarene family. Structural characterization by means of variable temperature NMR experiments and single crystal X-ray diffraction studies furthermore revealed that the resorcinarene core adopts different conformations in the solid state and in solution. peerReviewed
The Effect of Halogen Bonding on the Packing of Bromine Substituted Pyridine and Benzyl Functionalized Resorcinarene Tetrapodands in the Solid State
2012
The synthesis and characterization of new bromine-substituted pyridine and benzyl functionalized tetramethoxy resorcinarene tetrapodands are described and their solid-state structural properties and interactions were studied by single crystal X-ray crystallography. Three different crystal structures were obtained for the pyridine derivative and one for the benzyl derivative, which revealed that the interactions of the bromine substituent have an explicit effect on the crystal packing of the resorcinarene molecules. One of the structures obtained had very interesting halogen–halogen interactions with the same geometry as is generally found for compounds used in nonlinear optical studies. pee…
Stereocontrolled synthesis of fluorine-containing piperidine γ-amino acid derivatives
2019
An efficient synthetic approach for the construction of fluorine‐containing piperidine γ‐amino acid derivatives has been developed. The synthetic concept was based on oxidative ring opening of an unsaturated bicyclic γ‐lactam (Vince‐lactam) through its ring C=C bond, followed by double reductive amination of the diformyl intermediate performed with various fluoroalkylamines. The method has been extended towards the access of alkylated and perfluoroalkylated substances and for γ‐lactam derivatives. The transformations proceeded with stereocontrol: the configuration of the stereocenters in the products were predetermined by the configuration of the chiral centers of the starting γ‐lactam. The…
Photoluminescent Detection of Human T-Lymphoblastic Cells by ZnO Nanorods.
2020
The precise detection of cancer cells currently remains a global challenge. One-dimensional (1D) semiconductor nanostructures (e.g., ZnO nanorods) have attracted attention due to their potential use in cancer biosensors. In the current study, it was demonstrated that the possibility of a photoluminescent detection of human leukemic T-cells by using a zinc oxide nanorods (ZnO NRs) platform. Monoclonal antibodies (MABs) anti-CD5 against a cluster of differentiation (CD) proteins on the pathologic cell surface have been used as a bioselective layer on the ZnO surface. The optimal concentration of the protein anti-CD5 to form an effective bioselective layer on the ZnO NRs surface was selected. …
Orgaanisten yhdisteiden kiinteän tilan rakennemääritysmenetelmät
2011
Pro gradu -tutkielmassa käydään läpi 16 yleistä orgaanisten yhdisteiden kiinteän tilan rakennemääritysmenetelmää. Erityistä huomiota on tutkielmassa osoitettu röntgendiffraktiolle, kiinteän tilan NMR-spektroskopialle ja infrapunaspektroskopialle. Erikoistyössä valmistettiin kaksi uutta amidofoldameeriä ja yksi uusi sulfonyylifoldameeri. Valmistettujen yhdisteiden ominaisuuksia tutkittiin ja niitten rakenteet määritettiin. Lisäksi määritettiin yhden muodostetun fluorikompleksin rakenne.
pH and salivary sodium bicarbonate during the administration protocol for methotrexate in children with leukemia
2007
Objective: To analyze the behavior of pH and sodium bicarbonate (NAHCO3) in the saliva of patients with leukemia during the administration protocol for Methotrexate (Mtx). Materials and Methods: A controlled clinical essay was carried out on 23 patients between 4 and 18 years of age with high-risk Acute Lymphoblastic Leukemia. Sampling was carried out at To : basal condition; T1 : 12 hours after intravenous administration of sodium bicarbonate, before administering Mtx and T2 : 3 hours after administering Mtx, the time of maximum concentration. Chiron-Diagnostic 378® equipment was used to determine pH and sodium bicarbonate. The data was interpreted using Analysis of Variance at the 5% sign…
Frozen or dynamic? : An atomistic simulation perspective on the timescales of electrochemical reactions
2023
Electrochemical systems span a wide range of timescales, and several recent works have put forth the idea that the reaction environment should remain frozen and out of equilibrium during electrochemical electron or proton transfer reactions. Furthermore, simplified treatments of the electrochemical interface model the solvent and ions as frozen molecules. However, the claims and practices of a frozen environment strongly clash with most theoretical and simulation approaches developed to study electrochemical reaction rates. It has also been suggested that the electrode potential should not be fixed when simulating reaction rates due to conductivity limitations, which indicates constant pote…
Bisfosfonaatit : valmistus, ominaisuudet ja lääketieteellinen käyttö
2016
Tutkielman kirjallisessa osassa perehdytään bisfosfonaatteihin, niiden ominaisuuksiin ja valmistukseen sekä käyttöön lääketieteessä. Bisfosfonaattien valmistuksessa perehdytään sekä itse bisfosfonaattien että niiden johdannaisten valmistukseen. Bisfosfonaattien ominaisuuksia käydään läpi esittämällä niiden kemiallisia, biokemiallisia sekä farmakologisia ominaisuuksia ja vaikutustapoja. Eri bisfosfonaattien ominaisuuksia käsittelevät kappaleet on jaoteltu niistä käytettävän sukupolvijaottelun mukaisesti. Bisfosfonaattien käytössä pääosassa ovat niiden lääketieteelliset sovellukset. Bisfosfonaattien aihiolääkkeiden valmistuksessa keskitytään happoryhmän esteröintiin, amino- tai hydroksyyliryh…
Why Use Interactive Multi-Objective Optimization in Chemical Process Design?
2008
Problems in chemical engineering, like most real-world optimization problems, typically, have several conflicting performance criteria or objectives and they often are computationally demanding, which sets special requirements on the optimization methods used. In this chapter, we point out some shortcomings of some widely used basic methods of multi-objective optimization. As an alternative, we suggest using interactive approaches where the role of a decision maker or a designer is emphasized. Interactive multi-objective optimization has been shown to suit well for chemical process design problems because it takes the preferences of the decision maker into account in an iterative manner tha…