22 resultados para TANDEM
Resumo:
Kirjallisuusarvostelu
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Kirjallisuusarvostelu
Resumo:
Diplomityössä tavoitteena oli tutkia kapearailojauhekaaritekniikan soveltuvuutta konepajakäyttöön ja sen vaikutusta hitsauksen tuottavuuteen sekä hitsin mekaanisiin ominaisuuksiin. Työ tehtiin vertailukokeilla, jossa koehitsaukset suoritettiin eri aineenpaksuuksille siten, että jokaiselle tutkimuksen kohteena olleelle materiaalille tehtiin yksi hitsaus käytössä olevalla jauhekaaritekniikalla, jolloin saatiin vertailukohde, johon uutta kapearailotekniikkaa verrattiin. Tulokset osoittivat, että kapearailotekniikalla 1 palko/palkokerros aineenpaksuudeltaan Pl. 60 mm koekappale saatiin hitsattua n. 39 % nopeammin verrattuna perinteiseen tandem -hitsaukseen. Kyseisellä aineenpaksuudella lisäainelangan kulutus oli n. 41 % ja jauheen kulutus n. 71 % pienempi verrattuna perinteiseen X- railohitsaukseen tandem -menetelmällä. Lisäksi tuli esille, että ”palkoa palonpäälle” -tekniikka on kapearailotekniikoista tehokkain, sillä 2 palkoa/palkokerros menetelmässä railon leveyttä jouduttiin leventämään, jolloin kapearailotekniikan pieni railotilavuus menetettiin. Lisäaineen kulutus tälläkin menetelmällä jäi pienemmäksi verrattuna X- railohitsaukseen. Ennalta pelättyä kuonan irtoamisongelmaa ei kapearailohitsauksessa havaittu, vaan kuona irtosi ongelmitta railon kyljistä. Lisäksi kapearailotekniikalla hitsattujen hitsien lujuudet olivat vertailukelpoiset tandem- ja yksilankamenetelmällä hitsattujen hitsien kanssa.
Resumo:
Despite over 50 years of investigation, the precise cause of infant colic crying remains unresolved and the long-term consequences unrevealed, and an effective treatment is lacking. Indeed, a more profound understanding of the complex nature of infants’ excessive crying is needed. The purpose of this series of studies was to investigate the association between gut microbiota composition and infant crying, to evaluate the impact of colic crying on children’s later health and to study the possibilities of treating and preventing excessive crying with pro- and prebiotics. The material comprised three on-going, prospective randomized controlled trials of the probiotic Lactobacillus rhamnosus GG (ATCC 53103, LGG) or a mixture of prebiotics administered in early infancy. The study populations consisted of term infants (n=89), preterm infants (n=94) and term colic infants (n=30). Early crying was found to be inversely associated with the number of Bifidobacterium and Lactobacillus. Furthermore, at the age of 13 years functional gastrointestinal disorders (FGID) were manifested more frequently among children with previous colic crying than in those without. In preterm infants pro- and prebiotic supplementation during the first months of life reduced the frequency of excessive crying when compared to placebo. In parallel, probiotic LGG in tandem with a cow’s milk elimination diet and behavioral counseling reduced the daily crying amount among term colic infants when compared to placebo. In conclusion, the composition of the gut microbiota is associated with infant crying and colic, and probiotic LGG might provide a safe and effective treatment or preventive option to alleviate excessive crying in early infancy in term and preterm infants. Furthermore, early colic crying might be associated with the later development of FGID.
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Arkit: A-B4.
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Tannins, typically segregated into two major groups, the hydrolyzable tannins (HTs) and the proanthocyanidins (PAs), are plant polyphenolic secondary metabolites found throughout the plant kingdom. On one hand, tannins may cause harmful nutritional effects on herbivores, for example insects, and hence they work as plants’ defense against plant-eating animals. On the other hand, they may affect positively some herbivores, such as mammals, for example by their antioxidant, antimicrobial, anti-inflammatory or anticarcinogenic activities. This thesis focuses on understanding the bioactivity of plant tannins, their anthelmintic properties and the tools used for the qualitative and quantitative analysis of this endless source of structural diversity. The first part of the experimental work focused on the development of ultra-high performance liquid chromatography−tandem mass spectrometry (UHPLC-MS/MS) based methods for the rapid fingerprint analysis of bioactive polyphenols, especially tannins. In the second part of the experimental work the in vitro activity of isolated and purified HTs and their hydrolysis product, gallic acid, was tested against egg hatching and larval motility of two larval developmental stages, L1 and L2, of a common ruminant gastrointestinal parasite, Haemonchus contortus. The results indicated clear relationships between the HT structure and the anthelmintic activity. The activity of the studied compounds depended on many structural features, including size, functional groups present in the structure, and the structural rigidness. To further understand tannin bioactivity on a molecular level, the interaction between bovine serum albumin (BSA), and seven HTs and epigallocatechin gallate was examined. The objective was to define the effect of pH on the formation on tannin–protein complexes and to evaluate the stability of the formed complexes by gel electrophoresis and MALDI-TOF-MS. The results indicated that more basic pH values had a stabilizing effect on the tannin–protein complexes and that the tannin oxidative activity was directly linked with their tendency to form covalently stabilized complexes with BSA at increased pH.