Search results for "structures"
showing 10 items of 4815 documents
Semiautomatic growth analysis of multicellular tumor spheroids.
2011
Multicellular tumor spheroids (MCTS) are routinely employed as three-dimensional in vitro models to study tumor biology. Cultivation of MCTS in spinner flasks provides better growing conditions, especially with regard to the availability of nutrients and oxygen, when compared with microtiter plates. The main endpoint of drug response experiments is spheroid size. It is common practice to analyze spheroid size manually with a microscope and an ocular micrometer. This requires removal of some spheroids from the flask, which entails major limitations such as loss of MCTS and the risk of contamination. With this new approach, the authors present an efficient and highly reproducible method to an…
The occurrence of runt eggs in waterfowl clutches
2004
Abstract Eggs that are abnormally small are called runt eggs, and they occur in clutches across a wide variety of bird species. We surveyed waterfowl researchers to determine the natural frequency of occurrence of runt eggs in wild nesting ducks, geese, and swans. Of 551,632 eggs examined, 215 were runts, yielding a frequency of 0.039%. They occurred at about four times this frequency (0.156% in 21,832 eggs) in a museum oological collection. Runt eggs were not significantly more common within any taxonomic group among wild waterfowl, and their occurrence was not related to the mean clutch size of a species or to whether waterfowl exhibited regular conspecific nest parasitism. Cavity-nesting…
Impacts of ambient temperature and clutch size on incubation behaviour onset in a female-only incubator songbird
2021
Ambient temperature is assumed to be the major cue used by passerines to synchronize their laying and hatching dates to the expected peak of prey availability. While laying eggs, females are still able to fine-tune their hatching date following increasing or decreasing patterns of ambient temperature, mostly via changes in incubation onse t. The onset of incubation behaviour in relation to the laying sequence could have later conse- quences for the duration of the incubation period and the extent of hatching asynchrony. Clutch size is also known to affect incubation patterns and might therefore condition potential responses to changing temperatures. In this study we assessed the association…
Incubation and hatching periods in a Mediterranean Great Tit Parus major population
2014
Capsule The onset of incubation relative to clutch completion is highly variable in Great Tits Parus major, and has important consequences for the duration of the incubation and hatching periods.Aim To investigate when incubation starts relative to clutch completion, its effects on the length of the incubation and hatching periods, and which proximate factors affect all of these traits.Methods We used data from a Great Tit population in Eastern Spain collected over 15 years. Periodic visits to the nests (daily at some stages) allowed the determination of breeding parameters of interest. General linear models were used for analyses.Results On average, incubation started the day of laying of …
Nestling growth and mortality of Pied Flycatchers Ficedula hypoleuca in relation to weather and breeding effort
1996
The growth pattern and mortality of young Pied Flycatchers Ficedula hypoleuca were studied to focus on the mechanisms and constraints behind the widely studied optimization of clutch size. The clutch sizes were modified, and the growth and survival of chicks from different clutch sizes were monitored along with the prevailing weather during the nestling period to detect the effect of weather on reproductive success. The weather conditions during the feeding period of the nestlings varied within a season as well as between breeding seasons. The prevailing weather markedly affected both the growth rate and the survival of chicks, yet, the effects of weather on growth were not greater in enlar…
Breeding success of a colony of Boat-billed Herons Cochlearius cochlearius (Ciconiiformes: Ardeidae) in pasturelands of Costa Rica
2014
The breeding success of a double-brooding colony of Boat-billed Herons Cochlearius cochlearius was studied in pasturelands of Costa Rica. Mean clutch size in the first clutches (2.9 eggs/nest) was higher than in second and repeat clutches (2.3 eggs/nest). Breeding success was similar in the first attempt and second attempts(20.7 % and 21.7 %, respectively). In both attempts earlier nests enjoyed a higher breeding success. Starvation of the youngest chicks within the nest and destruction of nests by bad weather conditions were the main factors related to nestling death. No effects of human activity on the reproduction of the breeding colony were observed. Rev. Biol. Trop. 54 (4): 1131-1134. …
Direct subphthalocyanine conjugation to bombesin vs. indirect conjugation to its lipidic nanocarrier
2016
International audience; Bombesin (BBN) was covalently bound to graftable subphthalocyanine (SubPc) or to a cholesterol derivative, a component of a liposome that encapsulates non-graftable SubPc. The latter bioconjugation approach was suitable to address the stability of SubPc and was achieved by copper-free click-chemistry on the outer-face of the liposome. Liposomes were purified (FPLC) and then analyzed in size (outer diameter about 60 nm measured by DLS). In vitro binding studies allowed to determine the IC50 13.9 nM for one component of the liposome, cholesterol, conjugated to BBN. Hence, azido- (or alkynyl-) liposomes give fluorophores with no reactive functional group available on th…
A new method of anomeric protection and activation based on the conversion of glycosyl azides into glycosyl fluorides
1993
Glycosyl azides provide reliable anomeric protection stable to conditions for hydrolytic removal of ester groups, for reductive opening or release of acetalic diol protection, for the introduction of ether-type protection, and for glycosylation processes. The utility of this anomeric protection is further enhanced as glycosyl azides may be converted into glycosyl fluorides, which can be activated for glycosylation reactions. To this end, glycosyl azides have been subjected to 1,3-dipolar cycloaddition with di-tert-butyl acetylenedicarboxylate. On treatment with hydrogen fluoride-pyridine complex the N-glycosyl triazole derivatives directly give glycosyl fluorides.
High performance composites containing perfluoropolyethers-functionalized carbon-based nanoparticles: Rheological behavior and wettability
2016
Abstract Ultra High Molecular Weight Polyethylene (UHMWPE) based composites filled with carbon nanotubes (CNTs) and carbon black (CB) modified by perfluoropolyethers (PFPE) have been formulated. All composites show a segregated morphology with nanofillers selectively localized at the polymer particle–particle interface. The composites rheological properties have been deeply investigated: the PFPE functionalities linked on CNTs facilitate the semi-3D nanofillers network formation in the composites that show a solid-like behaviour even at lower investigated filler contents, reaching the rheological percolation threshold at lower nanofiller content than bare CNTs filled composites. For composi…
ISIM - INFRASTRUCTURES & STRUCTURES INFORMATION MODELING: A NEW CONCEPT OF BIM FOR INFRASTRUCTURES
2023
The application of Building Information Modeling (BIM) in infrastructure and structural projects, known as Integrated Structural and Infrastructure Modeling (ISIM), has gained attention in recent years due to its potential to revolutionize the construction industry. By providing a digital representation of the built environment, BIM allows for improved collaboration and communication between project stakeholders, leading to enhanced project outcomes. The ISIM approach is centered on the creation of a digital twin, a three-dimensional model of the infrastructure or structure, which serves as a virtual replica of the physical asset. This digital twin provides a platform for analysis, decision…