Search results for "Rite"
showing 10 items of 2726 documents
Supraphysiological doses of performance enhancing anabolic-androgenic steroids exert direct toxic effects on neuron-like cells.
2013
Anabolic-androgenic steroids (AAS) are lipophilic hormones often taken in excessive quantities by athletes and bodybuilders to enhance performance and increase muscle mass. AAS exert well known toxic effects on specific cell and tissue types and organ systems. The attention that androgen abuse has received lately should be used as an opportunity to educate both athletes and the general population regarding their adverse effects. Among numerous commercially available steroid hormones, very few have been specifically tested for direct neurotoxicity. We evaluated the effects of supraphysiological doses of methandienone and 17-α-methyltestosterone on sympathetic-like neuron cells. Vitality and …
Betulīna un tā piemaisījumu noteikšana, izmantojot AEŠH-UV-MS metodes
2016
Betulīna un tā piemaisījumu noteikšana, izmantojot AEŠH-UV-MS metodes. Autors: Zariņš Ainārs, zinātniskā vadītāja: Dr. Chem. Nakurte Ilva. Maģistra darbs, 50 lappuses, 17 attēli, 19 tabulas, 22 pielikumi, 43 literatūras avots. Latviešu valodā. Literatūras apskatā apkopota informācija par betulīnu, tā paraugos esošajiem iespējamajiem ķīmisko savienojumu piemaisījumiem un to analīzes metodēm. Darba praktiskajā daļā tika noteikts, kādus ķīmiskos savienojumus satur no bērza tāss iegūtais betulīns. To saturs noteikts, izmantojot gan šķidruma hromatogrāfiju – masspektrometriju, gan gāzu haromatogrāfiju-masspektrometriju un pēc iegūtajiem datiem izrēķināts savienojumu kvantitatīvais daudzums.
Bērza tāss etanola ekstraktvielu pamatkomponentu stabilitātes pētījumi
2017
Bērza tāss etanola ekstraktvielu pamatkomponentu stabilitātes pētījumi. Godiņa D., zinātniskais vadītājs no LU: Dr. chem. Ilva Nakurte un no LVKĶI: Dr. sc.ing. Aigars Pāže, bakalaura darbs, 49 lappuses, 20 attēli, 25 tabulas, 39 literatūras avoti. Latviešu valodā. Literatūras apskatā apkopota informācija par bērza tāss etanola ekstrakta sastāvu un sīkāk izklāstīts par pamatkomponentiem: betulīnu, betulīnskābi, lupeolu, ursolskābi. Aprakstītas iespējamās bērza tāss ekstrakta bioloģiski aktīvo savienojumu noteikšanas metodes: kopējo fenolu, antiradikālās aktivitātes un hromatogrāfiskās metodes. Veikta arī šo savienojumu stabilitātes pētījumu analīze. Bakalaura darba eksperimentālajā daļā veik…
Delta15N vērtību pielietojums ienestā minerālā slāpekļa aprites pētījumos mēslotās meža audzēs
2020
Maģistra darba ietvaros tika izpētīta zinātniskā literatūra par slāpekļa apriti dabā un meža ekosistēmās, ka arī dažādu faktoru ietekme uz slāpekļa aprites izmaiņām un slāpekļa izotopu attiecības izmaiņām koku, brūkleņu un melleņu paraugos. Eksperimentālajā daļā tika pētīta ienestā slāpekļa mēslojuma ietekme uz slāpekļa izotopu attiecības izmaiņām priedēs, mellenājos un brūklenājos. Šim eksperimentam tika ievākti 51 priežu skuju, 16 melleņu stublāju, 16 brūkleņu stublāju un lapu paraugi no dažādām meža audzēm, kuras tika mēslotas, izmantojot dažādus slāpekli saturošus ielabošanas veidus. δ15N un δ13C vērtības noteica, izmantojot izotopu attiecību masspektrometriju.
Evolution of the magma system of Pantelleria (Italy) from 190 ka to present
2022
The eruptive history of Pantelleria has been marked by the eruption of nine peralkaline ignimbrites, with inter-ignimbrite episodes from small, local volcanic centres. New whole-rock geochemical data are presented for seven ignimbrites and used with published data for younger units to track compositional changes with time. From»190 ka, silicicmagmatismwas dominated by comenditic trachyte to comendite compositions, evolving along generally similar liquid lines of descent (LLOD). The final ignimbrite, the Green Tuff (»46 ka), was tapped from a compositionally zoned pantelleritic upper reservoir to a trachytic mush zone. Younger (20–7 ka) silicic magmatism has been relatively small scale, with…
Anti-Inflammatory Triterpenes from Pistacia terebinthus Galls
2002
From the galls of Pistacia terebinthus we obtained an extract that proved to be effective against chronic and acute inflammation. Now we report on the isolation and identification of three triterpenes: two tirucallane-type lanostanoids and one oleanane, which we have identified as masticadienonic acid (1), masticadienolic acid (2), and morolic acid (3), respectively. All of them showed effectiveness on the mouse ear inflammation induced by repeated applications of 12-O-tetradecanoylphorbol 13-acetate and on the phospholipase A2-induced foot paw edema. The pharmacological activity of the compounds was ratified by a histological study of the ear samples. In addition, they inhibited leukotrien…
Spectral and microscopic study of self-assembly of novel cationic spermine amides of betulinic acid
2016
Supramolecular characteristics of two spermine amides of betulinic acid (1 and 2) were studied by measuring and evaluating their UV-VIS-NIR spectra in aqueous acetonitrile and DOSY-NMR spectra in tetradeuteromethanol, accompanied by atomic force microscopy (AFM) images, scanning electron microscopy (SEM) micrographs, and transmission electron microscopy (TEM) micrographs. Fibrous supramolecular self-assembly of 1 and 2 was observed by AFM images, as well as by the SEM and TEM micrographs. Bathochromic shifts of the absorbance maximum at 870nm to 1015-970nm in the UV-VIS-NIR spectra were observed with increasing water content in the acetonitrile/water systems, indicating formation of fibrous…
Two new biologically active triterpene saponins from Acanthophyllum squarrosum.
2000
Two novel triterpenoid saponins (1 and 2) have been isolated from the roots of Acanthophyllum squarrosum. The structures were established mainly by a combination of 2D NMR techniques as 3-O-beta-D-galactopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-be ta-D-glucuronopyranosylgypsogenin-28-O-beta-D-xylopyranosyl-(1-->3 )-b eta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L- rhamnopyranosyl-(1-->3)]-beta-D-fucopyranoside (1) and 3-O-beta-D-glucopyranosylgypsogenin-28-O-alpha-L-rhamnopyranosyl-( 1-- >2)-alpha-L-arabinopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->6 )]- beta-D-glucopyranoside (2). Compound 1 showed a moderate concentration-dependent immunomodulatory effect …
Acylated triterpene saponins from Silene jenisseensis
1995
Abstract From the roots of Silene jenisseensis a new trans-p-methoxycinnamoyl triterpene saponin has been isolated along with its cis-p-methoxycinnamoyl isomer as an inseparable mixture. Their structures were established by chemical means and spectroscopic methods including 1D- and 2D-homonuclear and heteronuclear correlation NMR spectroscopy as 3-O-[β- d -galactopyranosyl -(1 → 2)-β- d -glucuronopyranosyl ]-28-O-[β- d -glucopyranosyl -(1 → 2)-α- l - rhamnopyranosyl -(1 → 2)-β- d -4-O-trans-p- methoxycinnamoyl-fucopyranosyl ] quillaic acid and its cis-isomer, respectively. They did not show any activity in the in vitro chemoluminescence granulocytes assay, but exhibited only a weak inhibito…
Triterpene Saponins from Cyclamen persicum
2010
A new triterpene saponin 3- O-β-D-glucopyranosyl-(1→4)-α-L-arabinopyranosyl-16α-hydroxy-13β,28-epoxy-oleanan-30-al (1), along with four known triterpene glycosides (2-5) were isolated from Cyclamen persicum. Their structures were characterized by a combination of 1D- and 2D-NMR (1H-1H COSY, TOCSY, NOESY, HSQC, and HMBC) and MS spectrocopic data. The cytotoxicity of compounds 2 and 4 was evaluated using two human colon cancer cell lines HT-29 and HCT 116.