Search results for "LAB"

Efficient microwave-assisted direct radiosynthesis of [(18)F]PR04.MZ and [(18)F]LBT999: selective dopamine transporter ligands for quantitative molec…

2009

Abstract PR04.MZ 8-(4-fluoro-but-2-ynyl)-3- p -tolyl-8-aza-bicyclo[3.2.1]octane-2-carboxylic acid methyl ester ( 1 ) and LBT999 8-(( E )-4-fluoro-but-2-enyl)-3b- p -tolyl-8-aza-bicyclo[3.2.1]octane-2β-carboxylic acid methyl ester ( 2 ) are selective dopamine reuptake inhibitors, derived from cocaine. Compounds 1 and 2 were labelled with fluorine-18 at their terminally fluorinated N-substituents employing microwave enhanced direct nucleophilic fluorination. K[ 18 F]F − Kryptofix ® 222 cryptate, tetrabutyl ammonium [ 18 F]fluoride and caesium [ 18 F]fluoride were compared as fluoride sources under conventional and microwave enhanced conditions. Fluorination yields were remarkably increased un…

Synthesis and Evaluation of Novel Ring‐Strained Noncanonical Amino Acids for Residue‐Specific Bioorthogonal Reactions in Living Cells

2021

Abstract Bioorthogonal reactions are ideally suited to selectively modify proteins in complex environments, even in vivo. Kinetics and product stability of these reactions are crucial parameters to evaluate their usefulness for specific applications. Strain promoted inverse electron demand Diels–Alder cycloadditions (SPIEDAC) between tetrazines and strained alkenes or alkynes are particularly popular, as they allow ultrafast labeling inside cells. In combination with genetic code expansion (GCE)‐a method that allows to incorporate noncanonical amino acids (ncAAs) site‐specifically into proteins in vivo. These reactions enable residue‐specific fluorophore attachment to proteins in living mam…

A virtual laboratory designed for teaching diffractive lenses

2010

[EN] We present a virtual laboratory generated in Matlab GuiQc (Graphical User Interface) for its use in Optics courses as an informatic tool for teaching the focusing properties of a diffractive lens. This Gui allows the students to learn easily and rapidly about the influence on the focal volume of the lens construction parameters. As an example in this work we analyze fractal diffractive lenses because we found that fractal geometry is a highly motivating topic for students since it is related to a wide range of scientific and technological phenomena.

Computer-supported collaboration in a scripted 3-D game environment

2005

The particular focus of this paper is on scripting collaboration in a 3-D virtual game environment intended to make learning more effective, but also take into account the risk of over-scripting learning. The empirical experiment eScape, which encourages learners to solve problems collaboratively, is also presented. This study attempts to find out whether the features of 3-D games can be used to create meaningful scripted collaborative learning environments. The results indicated that scripting persuaded student teams to enter into collaboration, but the actual processes varied.

Improving Serendipity and Accuracy in Cross-Domain Recommender Systems

2017

Cross-domain recommender systems use information from source domains to improve recommendations in a target domain, where the term domain refers to a set of items that share attributes and/or user ratings. Most works on this topic focus on accuracy but disregard other properties of recommender systems. In this paper, we attempt to improve serendipity and accuracy in the target domain with datasets from source domains. Due to the lack of publicly available datasets, we collect datasets from two domains related to music, involving user ratings and item attributes. We then conduct experiments using collaborative filtering and content-based filtering approaches for the purpose of validation. Ac…

Woven folklore: computers promoting cross-cultural understanding

2004

Multicultural cooperation requires participants to understand the cultural background and identity of all the partners. In this respect, computers provide the cooperation with a new and interesting instrument. A team of students from two schools, one in Tanzania, another in Finland, implemented a multimedia version of an African folklore story. A computer served as a platform for genuine cooperation: the whole team worked on one electronic artefact, despite the geographical distance between the members. The collaborative process helped each participant to clarify his/her own cultural background whilst also becoming acquainted with that of his/her distant partner.

Fluorometric determination of chemically available lysine: adaptation, validation and application to different milk products.

2004

A spectrophotometric method based on the reaction between available lysine and ortho-phthaldialdehyde (OPA) was adapted and validated for fluorometric determination of the chemically available lysine contents in milk matrices (UHT and conventional in-bottle sterilized cow milk, milk-based infant formulas and infant formula ingredients). The values of the analytical parameters show its usefulness as a routine method (linearity, r = 0.9992; detection limit, 0.0066 mg/mL assay; accuracy, 99-108%; precision, intra-day 2.1-5.9% and inter-day 3.5 10.2%). No statistically significant differences (p < 0.05) were found between the values obtained with the adapted method and those obtained applying t…

Bioavailability and metabolism.

2002

Impact of parasitoid-associated polydnaviruses on plant-mediated herbivore interactions

2022

Insect herbivores interact via plant-mediated interactions in which one herbivore species induces changes in plant quality that affects the performance of a second phytophagous insect that shares the food plant. These interactions are often asymmetric due to specificity in induced plant responses to herbivore attack, amount of plant damage, elicitors in herbivore saliva and plant organ damaged by herbivores. Parasitoids and their symbiotic polydnaviruses alter herbivore physiology and behaviour and may influence how plants respond to parasitized herbivores. We argue that these phenomena affect plant-mediated interactions between herbivores. We identify that the extended phenotype of parasit…

Impact of conventional and non-conventional processing on prickly pear ( Opuntia spp.) and their derived products: From preservation of beverages to …

2017

Abstract Background In recent years, both food researchers and food industry have shown growing interest in Opuntia fruits, as they constitute a good source of phytochemicals such as phenolics, vitamin C, vitamin E, polysaccharides and betalains. Many of these compounds have shown antioxidant, anti-cancer, antiatherosclerotic and/or hepatoprotective properties. Moreover, the fruit is also a source of dietary fibers, which promote bowel transit, thus preventing constipation. Scope and approach Due to these properties, Opuntia fruits are considered as functional products offering numerous health benefits when are consumed as fresh or processed product. However, these compounds can lose their …