Search results for "DAS"
showing 10 items of 4164 documents
Microwave-assisted saponification of animal greases for cholesterol determination
1998
Abstract An alternative method for the hydrolysis of cholesterol esters in animal grease samples has been developed. The method consists of the microwave-assisted treatment of 4 g of animal fat or oil with 40 ml of an ethanolic KOH solution inside a 115 ml closed reactor in which samples were irradiated for 2.5 min at 50% power level of an exit power of 700 W. After extraction with petroleum ether and dissolution of the unsaponifiables in toluene, total cholesterol was determined spectrophotometrically by using p-anisidine as a test reagent of the enzymatic reaction of cholesterol through a bienzymic reactor in which cholesterol oxidase and horseradish peroxidase were noncovalently immobili…
A chemiluminescence flow-based procedure for determination of carbaryl in natural waters exploiting multicommutation and enzymatic reaction
2007
A chemiluminescence procedure for the determination of carbaryl in natural waters using acetylcholinesterase and choline oxidase is described. The flow system designed to implement multicommutation approach controlled by microcomputer comprised five solenoid valves, two columns with immobilized enzymes on controlled pore glass beads and chemiluminometric flow cell. In the best experimental conditions a linear response ranging from 25 to 700 µg L-1 carbaryl was obtained. Water samples were spiked with carbaryl in order to access the accuracy and recoveries between 95 and 101% were obtained for a concentration level ranging from 25 to 100 µg L-1 carbaryl. Detection limit and variation coeffic…
New Reusable Solid Biosensor with Covalent Immobilization of the Horseradish Peroxidase Enzyme: In Situ Liberation Studies of Hydrogen Peroxide by Po…
2019
Herein, we reported a chemiluminescent biosensor based on the covalent immobilization of the horseradish peroxidase (HRP) enzyme on a polydimethylsiloxane (PDMS) support to quantify in situ hydrogen peroxide (H2O2). The chemiluminescent reaction based on the use of luminol as an oxidizable substrate, with HRP as the catalyst, has been used in order to quantify H2O2 as the oxidizing agent. The performance of the proposed biosensor has been demonstrated to determine H2O2 liberated by cells in a culture medium and for evaluating the delivery of H2O2 from denture cleaner tablets, as examples of application. For both analyses, the results indicated that the biosensor is cost-effective, sensitive…
Flow injection determination of free and total cholesterol in animal greases using enzymes in non-aqueous media
1998
A non-covalently coimmobilized bienzymic reactor of horseradish peroxidase (HRP) and cholesterol oxidase (COD), operating in a continuous organic flowing stream of 1 × 10–3 M p-anisidine in buffer-saturated (pH 7.0) toluene, has been employed for cholesterol determination in animal greases, such as pig, beef, and chicken fat, and codfish liver oil. The method provides a good linear relationship up to 1.8 × 10–3 M cholesterol and average recoveries of 99.5%, a high sensitivity, with a detection limit of 1 × 10–6 M of cholesterol and a good precision (an interday RSD of 1.8% for the determination of total cholesterol in a codfish oil sample). The method permits the direct spectrophotometric d…
Hybrid Chelator-Based PSMA Radiopharmaceuticals: Translational Approach
2021
(1) Background: Prostate-specific membrane antigen (PSMA) has been extensively studied in the last decade. It became a promising biological target in the diagnosis and therapy of PSMA-expressing cancer diseases. Although there are several radiolabeled PSMA inhibitors available, the search for new compounds with improved pharmacokinetic properties and simplified synthesis is still ongoing. In this study, we developed PSMA ligands with two different hybrid chelators and a modified linker. Both compounds have displayed a promising pharmacokinetic profile. (2) Methods: DATA5m.SA.KuE and AAZTA5.SA.KuE were synthesized. DATA5m.SA.KuE was labeled with gallium-68 and radiochemical yields of various…
11. klases skolēnu valodas kompetences attīstīšana latviešu valodas paveidiem veltītajās stundās
2017
Diplomdarbā 11. klases skolēnu valodas kompetences attīstīšana latviešu valodas paveidiem veltītajās stundās izvirzīts mērķis attīstīt 11. klases skolēnu valodas kompetenci, izmantojot dialektoloģijas jautājumu un latgaliešu rakstu valodas nozīmes izpratnes sekmēšanai paredzētu lingvodidaktisko materiālu. Diplomdarbs ietver trīs nodaļas. Pirmajā nodaļā piedāvāts ieskats teorētiskajās atziņās, kas aktuālas un būtiskas pētāmās problēmas aspektā, otrajā nodaļā izmēģinājumdarbībā iesaistīto skolēnu pedagoģiski psiholoģiskais raksturojums, pētījumā iesaistītās klases raksturojums, trešajā nodaļā didaktiskā materiāla izstrāde un aprobācija. Pētījuma rezultātā secināts, ka izdevies pilnveidot un p…
Linguistica Lettica, Nr. 30
2022
Žurnāla "Linguistica Lettica" 30. numura tēma ir "Valodas bagātība slēpjas tās dažādībā". The theme of the 30th issue of the annual journal "Linguistica Lettica" is "The richness of language lies in its diversity".
Mast cells promote homeostasis by limiting endothelin-1-induced toxicity
2004
Endothelin-1 (ET-1) is a 21-amino-acid peptide, derived from vascular endothelial cells, with potent vasoconstrictor activity. ET-1 has been implicated in diverse physiological or pathological processes, including the vascular changes associated with sepsis. However, the factors that regulate ET-1-associated toxicity during bacterial infections, or in other settings, are not fully understood. Both the pathology associated with certain allergic and autoimmune disorders, and optimal host defence against bacterial and parasitic infections are mediated by mast cells. In vitro, mast cells can produce ET-1 (ref. 11), undergo ET-1-dependent and endothelin-A receptor (ET(A))-dependent activation, a…
The importance of a highly active and DeltapH-regulated diatoxanthin epoxidase for the regulation of the PS II antenna function in diadinoxanthin cyc…
2005
The present study focuses on the regulation of diatoxanthin (Dtx) epoxidation in the diadinoxanthin (Ddx) cycle containing algae Phaeodactylum tricornutum, Thalassiosira pseudonana, Cyclotella meneghiniana and Prymnesium parvum and its significance for the control of the photosystem II (PS II) antenna function. Our data show that Dtx epoxidase can exhibit extremely high activities when algal cells are transferred from high light (HL) to low light (LL). Under HL conditions, Dtx epoxidation is strongly inhibited by the light-driven proton gradient. Uncoupling of the cells during HL illumination restores the high epoxidation rates observed during LL. In Ddx cycle containing algae, non-photoche…
Innovative and Applied Research in Biology: Proceedings
2022
The collection contains SCIENTIFIC articles on the topics of the LU 80 conference reports. The main focus is on innovative and applied research in biology and interdisciplinary fields.