1,721,021 research outputs found
Bioencapsulation of Oocytes and Granulosa Cells
No full textA protocol for the encapsulation in sodium alginate of granulosa cells in primary culture and co-culture of oocyte-cumulus complexes is reported. Sodium alginate forms strong gels when jellified with barium ions, allowing the self-organization of cells into a 3D structure. This method of encapsulation is simple and cheap, allowing the culture of cells in a 3-dimensional fashion
Energy homeostasis in rabbit does during pregnancy and pseudopregnancy
Full text linkThis study was conducted to evaluate the changing concentrations of metabolic hormones and metabolites in pregnant (P) and pseudopregnant (PP) rabbit does. Twenty-five New Zealand White rabbit does were submitted to artificial insemination (AI) and then classified as P (n = 15) or PP (n = 10). Blood samples were collected weekly until day 32 post AI. During pregnancy, leptin concentrations were greater on Days 14 and 21 (P < 0.05), while insulin was greater on days 21 and 32 post AI (P < 0.05) compared to PP does. The triiodothyronine/thyroxine (T3/T4) ratio was greater in the first and last week (P < 0.001); whereas, cortisol concentrations were greater in the last week of pregnancy and after parturition (P < 0.01) compared with that of PP does. Non-esterified fatty acids (NEFA) concentrations increased from day 7 until day 32 post AI (P < 0.05). Glucose concentrations were unchanged throughout pregnancy although concentrations were positively associated with litter size. These results indicate concentrations of hormones and metabolites change during pregnancy to ensure energy requirements are met for both the foetuses and the maternal tissues. Physiological hyperleptinemia, hyperinsulinemia, and changes in cortisol as well as thyroid hormones indicate there is an adaptation of metabolic functions induced by pregnancy. These adaptations could be mediated by gonadal steroids because changes mainly occur in the second half of pregnancy when the profile of the sex hormones differs between P and PP does
Effects of Diets Enriched in Linseed and Fish Oil on the Expression Pattern of Toll-Like Receptors 4 and Proinflammatory Cytokines on Gonadal Axis and Reproductive Organs in Rabbit Buck
Full text linkInfections of the genital tract can perturb the fertility in humans and animals. Pathogen recognition and activation of innate immunity onset through the pattern recognition receptor activation, such as Toll-like receptor 4 (TLR4), leading to the production of proinflammatory cytokines and mediators. TLR4 is expressed both on leukocytes and nonimmune cells. Rabbit TLR4 shows great similarity to its human counterpart. Moreover, the TLR4 signalling pathway could be modulated by long-chain polyunsaturated fatty acids (LC-PUFA). The objectives of this study were (i) to determine the expression levels of TLR4 and proinflammatory cytokines in the reproductive hypothalamic-gonadal axis of the male rabbit and (ii) to evaluate if the n-3 PUFA-enriched diets can modify their expression levels in the tissues and LC-PUFA profiles in seminal plasma. Fifteen rabbit bucks (n=5/experimental group) were fed with different diets: Commercial standard (group C), rich in extruded linseed (10%, group L), and in fish oil (3%, group FO) for 110 days. TLR4, TNF-, and IL-1β mRNA were ubiquitously expressed throughout the hypothalamic-gonadal axis. However, TLR4 mRNA expression was lower in the hypothalamus than the epididymis (P<0.01), seminal vesicles (P<0.01), and pituitary gland (P<0.05). Dietary enrichment in PUFA did not modify the gene expression profile nor the histological characteristics of the tissues. Conversely in seminal plasma, rabbits fed with L and FO had lower n-6 (P<0.05), LC-PUFA n-6 (P<0.05), and n-6/n-3 ratio (P<0.05) but higher n-3 (P<0.001) and LC-PUFA n-3 (P<0.01) compared to the control group. Our study builds a map of the gene expression of TRL4 and proinflammatory cytokines in the reproductive hypothalamic-gonadal axis of the male rabbit, fundamental step for understanding the immune defence mechanisms. Diets enriched in LC-PUFA did not affect basal gene expression but modulated sperm fatty acid composition. Finally, rabbit may be an excellent animal model to study the relationship between inflammation and infertility, and the nutritional modulation of immune functions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
PHYSIOLOGICAL APPROACH TO THE STUDY OF AUTOCHTHONOUS CATTLE BREEDS OF NORTHERN ITALY
Full text linkThis PhD project is focused on the physiological characterization of some autochthonous bovine breeds of Northern Italy, using many biological parameters in order to make a comparison with the cosmopolitan breeds. Despite the lower milk production, these breeds present other interesting and peculiar features, such as rusticity, frugality, good food conversion, high product quality (milk and meat), good fertility and good resistance and resilience against the diseases. We applied a multidisciplinary approach to study the physiological bases of the interesting traits present in the local breeds, studying three main issues: the metabolism of the transition period, the milk composition and technological properties and the ethological traits.
a) Biodiversity of the transition period
i) Study of the milk ketone bodies assessment in Modenese breed and Holstein with a characterization of physiological, reproductive and productive performances.
The objective of this study was to characterize some productive, reproductive and metabolic parameters (ketone bodies) in the Italian autochthonous cattle breed Modenese, comparing them with those of Holstein and their crossbred (F1=Modenese x Holstein; F2=Modenese x F1) breed in the same farm, in order to understand if there is a different metabolic picture that can influence the reproductive performances. Milk samples have been collected at different times of lactation (20, 40, and 90 days in milk (DIM)) and analyzed by gas chromatography-mass spectrometry to obtain the the concentration of ketone bodies. In all time points, the Modenese breed showed a significant (p<0,05) lower concentration of ketone bodies. The F1, F2 and Modenese showed also better reproductive performances when compared to Holstein, with a significant lower (p<0,05) length of days open period.
ii) Comparative evaluation of the transition period: Italian autochthonous breed vs. Holstein
We evaluated the metabolic indicators, milk protein profiles and the milk microbiota in 6 Holstein Friesian and 4 Rendena cows reared on the same farm and under the same management conditions. Quarter milk samples and blood were collected from all cows at dry-off (T1), 1 day after calving (T2), 7-10 days after calving (T3) and 30 days after calving (T4). Blood samples were used for the analysis of plasma metabolites such as: glucose, total cholesterol, urea, inorganic phosphorus, total protein, albumin, total bilirubin, aspartate aminotransferase (GOT), γ-glutamyltransferase (GGT), creatinine, NEFA, β-OH-butyric acid (BHBA), thiol groups (SHp) and ferric reducing antioxidant power (FRAP). Quarter milk samples were subjected to bacteriological culture, protein profiles and characterization of the milk microbiota. Holstein cows showed a more severe fat mobilization, lower muscle mobilizationand systemic inflammatory response at T2 and T3 in comparison with Rendena cows. Significant differences were seen in the general composition of the milk microbiota of the two breeds. Concerning the milk protein abundance profile, pronounced differences were seen in the colostrum (T2), with significantly higher amounts of protective molecules (immunoglobulins and other immune-related proteins) in Rendena.
b) “Milks” biodiversity
i. Fatty acid profile, desaturase and atherogenic indices in milk of Holstein Friesian and Italian autochthonous cattle breeds
In this study the characteristics of the fatty acid profile in local Italian bovine breeds (Cabannina, Varzese, and Valdostana) are compared with those of Friesian, , a conventional breed, during the first period of lactation. The local breeds show a general trend to have higher unsaturated fatty acid percentages, as well as lower desaturase indices (related to C14, C16 and C18) and atherogenic index, with respect to Friesian cows.
ii. NMR-based metabolomics as a tool to characterize the milk biodiversity
In the present study we investigated the variations of the metabolic profiles during lactation in milks obtained from Friesian and autochthonous breeds from Northern Italy by 1H-NMR metabolomics. Furthermore, the external factors influencing the milk composition were minimized: the cows were bred on the same farm, were fed with the same diet, and were matched by for the lactation interval and lactation stage. Our results showed a difference in milk composition between breeds and in relation to stage of lactation.
iii. Milk microbiome characterization between healthy Holstein Friesian and Rendena cows
The aim of this study was to compare the milk microbiota in 6 Holstein and 3 Rendena cows reared on the same farm under the same management conditions, with a special focus on the transition period. Four time points (dry-off, 1 day after calving, 7-10 days after calving and 30 days after calving) were considered. The taxonomic profiles of cosmopolitan and local breeds were dominated by Firmicutes, mostly represented by the Streptococcus genus, followed by Proteobacteria, Bacteriodetes, and Actinobacteria. In both Rendena and Holstein the most abundant species was represented by Str. thermophilus, a lactic acid bacterium widely used in the fermentation of dairy products. However, the microbial populations were profoundly different in the two breeds along all the time points: the Rendena milk samples showed lower biodiversity and more stable microbial ecosystem.
c) Ethological biodiversity
i. Cattle Personality biodiversity in autochthonous Italian breeds: a pilot survey
This study assessed personality in five different cattle breeds (Bos taurus), two cosmopolitan (Holstein and Brown) and three Italian autochthonous, through a personality questionnaire completed by handlers (milkers). The objective was to determine whether this method could detect differences in personality, including breed, age and sex differences. Milkers’ assessments found breed and individual differences in the animals studied. Differences in personality traits resulted to be quite evident between individuals but consistent within each breed.
With these results, we have shed some light on the physiological mechanism at the base of the interesting features showed by the autochthonous Italian cattle breeds. This can contribute to the re-evaluation of bovine local breeds and their products, in order to recover the continuously reducing numbers, and enhance the quality of derived products, with positive effects on farm economy and biodiversity
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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