Search results for "Urea"

Purification and spectroscopic studies on catechol oxidases from Lycopus europaeus and Populus nigra: evidence for a dinuclear copper center of type …

1999

We purified two catechol oxidases from Lycopus europaeus and Populus nigra which only catalyze the oxidation of catechols to quinones without hydroxylating tyrosine. The molecular mass of the Lycopus enzyme was determined to 39,800 Da and the mass of the Populus enzyme was determined to 56,050 Da. Both catechol oxidases are inhibited by thiourea, N-phenylthiourea, dithiocarbamate, and cyanide, but show different pH behavior using catechol as substrate. Atomic absorption spectrosopic analysis found 1.5 copper atoms per protein molecule. Using EPR spectroscopy we determined 1.8 Cu per molecule catechol oxidase. Furthermore, EPR spectroscopy demonstrated that catechol oxidase is a copper enzym…

De cómo la realidad se quedó fuera del cuadro en el cine de los orígenes

2013

La Leyenda de los santos : orígenes medievales e itinerario renacentista

2016

This is an analysis of the trajectory of one of the two great families of our Medieval and Renaissance flos sanctorum. This family is formed of three works: the handwritten Compilación B (an abridged version of the Legenda aurea of Iacopo da Varazze), the Flos Sanctorum con sus ethimologías (an incunabulum of unknown date and printer) and the Leyenda de los santos, a work that thrived with several editions published since the end of the 15th century until 1579. This article explores the relationship between these three works and also analyses the specific affiliation of their principal manuscript copies and editions, concluding with how the texts have evolved from these first manuscript ver…

Influence of photo-initiators in the preparation of methacrylate monoliths into poly(ethylene-co-tetrafluoroethylene) tubing for microbore HPLC.

2020

[EN] In this study, poly(butyl methacrylate-co-ethyleneglycol dimethacrylate) polymeric monoliths were in situ developed within 0.75 mm i.d. poly(ethylene-co-tetrafluoroethylene) (ETFE) tubing by UV polymerization via three different free-radical initiators fscce-azobisisobutyronitrile (AIBN), 2,2-dimethoxy-2-phenylacetophenone (DMPA) and 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (MTMPP). The influence of the nature of each photo-initiator and irradiation time on the morphological features of the polymer was investigated by scanning electron microscopy, and the chromatographic properties of the resulting microbore columns were evaluated using alkyl benzenes as test substances. The …

Satisfaction with the clinical practice among nursing students using regression models and qualitative comparative analysis

2020

Abstract Background Clinical practice is considered fundamental in nursing studies for the effective education of nurses and students' satisfaction. Both the clinical environment and the clinical educator are key factors in students´ satisfaction. Objectives To analyze the influence of the socio-demographic variables of clinical educators and nursing students on satisfaction with the clinical practice. Design This was an observational, cross-sectional study. Settings A clinical practice course at a private university in Valencia, Spain. Participants The study included 527 nursing students enrolled on the clinical practice, supervised by 187 clinical educators. Methods Two statistical method…

Solutions to replace quantity with quality in science.

2012

In their recent letter, Joern Fischer and others [1xAcademia's obsession with quantity. Fischer, J. et al. Trends Ecol. Evol. 2012; 27: 463–474See all References[1] tackled one of the major problems in modern science: the obsession with quantity. Perspicaciously, they showed how targeting for quantity has faded out creativity and reflection from science. Fischer and others ended their letter with the words: ‘Starting with our own university departments (but not stopping there), it is time to take stock of what we are doing. We must recreate spaces for reflection, personal relationships, and depth. More does not equal better.’ Utopian as it may be, we applaud this statement.Unfortunately, Fi…

Sulfate-Templated 2D Anion-Layered Supramolecular Self-Assemblies

2019

Summary Using solution and solid-state analyses, we demonstrate that the tripodal N-methylated(1,3,5-benzene-tricarboxamide)-tris(phenylurea) BTA ligands, possessing urea functionalities in the meta position, are able to form extended self-assembly 2D networks via hydrogen bonding templated by sulfate (SO42–). The divergence of the urea binding sites confers a propeller-like conformation to the ligands and is key to formation of the self-assemblies. Studies in solution and in the solid state as well as scanning electron microscopy (SEM) on the self-assembly properties of the ligands showed that the convergence also leads to the formation of hierarchical structures, including porous films an…

The cockroach Blattella germanica obtains nitrogen from uric acid through a metabolic pathway shared with its bacterial endosymbiont.

2014

Uric acid storedin the fat bodyof cockroaches is a nitrogen reservoirmobilized in times of scarcity. The discovery of urease in Blattabacterium cuenoti, the primary endosymbiont of cockroaches, suggests that the endosymbiont may participate in cockroach nitrogen economy. However, bacterial urease may only be one piece in the entire nitrogen recycling process from insect uric acid. Thus, in addition to the uricolytic pathway to urea, there must be glutamine synthetase assimilating the released ammonia by the urease reaction to enable the stored nitrogen to be metabolically usable. None of the Blattabacterium genomes sequenced to date possess genes encoding for those enzymes. To test the host…

Hydroponic Lettuce Cultivation Using Organic Nutrient Solution from Aerobic Digested Aquacultural Sludge

2021

The aim of this study was to demonstrate how aquacultural sludge can be processed and utilized as an organic nutrient solution (ONS) for hydroponic lettuce production. By using a previous developed method, approximately 80% of the processed sludge was reclaimed as a clear, nutrient-rich solution. The performance of the recovered nutrient solution on lettuce growth was assessed in a nutrient film hydroponic system. The results were compared to the results obtained using a conventional nutrient solution (CNS). Yield, fresh weight, water consumption, and nutrient and heavy metal content in leaf tissue were measured. In spite of a 16% lower average fresh weight obtained in ONS compared to the w…

Birokrātismi sabiedriskajā saziņā

2016

Darbs pēta birokrātismus sabiedriskajā saziņā. Darba mērķis ir izpētīt, kā veidojas nozīme Eiropas Savienības (ES) diskursā un atklāt vissarežģītākos aspektus priekš tiem valodas lietotājiem, kam angļu valoda nav dzimtā. Šī darba loks ir sašaurināts līdz vienam programmas Horizon 2015 dokumentam, un visi piemēri šajā darbā ir ņemti no iepriekšminētā dokumenta. Pētnieciskā metode ir diskursa analīze. Autore pieradīja ka zināmas birokrātismu pazīmes, kā īpašības vārdi un modalitāte, var rādīt dokumentā neskaidrību . Šī darba rezultāti ir piemēru, paskaidrojumu un rekomendāciju kopsavilkums, kas varētu palīdzēt strādāt ar neskaidras valodas gadījumiem un ES dokumentācijas praktisks pētījums, k…