151 research outputs found

    The chemokine Sdf-1 and its receptor Cxcr4 are required for formation of muscle in zebrafish

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    <p>Abstract</p> <p>Background</p> <p>During development cell migration takes place prior to differentiation of many cell types. The chemokine receptor Cxcr4 and its ligand Sdf1 are implicated in migration of several cell lineages, including appendicular muscles.</p> <p>Results</p> <p>We dissected the role of <it>sdf1</it>-<it>cxcr4 </it>during skeletal myogenesis. We demonstrated that the receptor <it>cxcr4a </it>is expressed in the medial-anterior part of somites, suggesting that chemokine signaling plays a role in this region of the somite. Previous reports emphasized co-operation of Sdf1a and Cxcr4b. We found that during early myogenesis Sdf1a co-operates with the second Cxcr4 of zebrafish – Cxcr4a resulting in the commitment of myoblast to form fast muscle. Disrupting this chemokine signal caused a reduction in <it>myoD </it>and <it>myf5 </it>expression and fast fiber formation. In addition, we showed that a dimerization partner of MyoD and Myf5, E12, positively regulates transcription of <it>cxcr4a </it>and <it>sdf1a </it>in contrast to that of Sonic hedgehog, which inhibited these genes through induction of expression of <it>id2</it>.</p> <p>Conclusion</p> <p>We revealed a regulatory feedback mechanism between <it>cxcr4a</it>-<it>sdf1a </it>and genes encoding myogenic regulatory factors, which is involved in differentiation of fast myofibers. This demonstrated a role of chemokine signaling during development of skeletal muscles.</p

    Etude numérique de l'impact du filtrage optique sur les propriétés régénératives d'un convertisseur de longueur d'onde interférométrique en configuration différentielle

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    Session affiches 19 « Systèmes et réseaux de Télécommunication » [A10.2]National audienceDans cet article, nous présentons l'étude numérique des propriétés régénératives d'un convertisseur de longueur d'onde interférométrique à base d'amplificateurs optiques à semiconducteurs, en configuration différentielle. Nous avons démontré qu'en optimisant le filtrage optique, nous pouvons améliorer la qualité du signal en sortie du convertisseur en réduisant notamment l'effet de « patterning » lié à la réponse lente de l'amplificateur optique à semiconducteurs

    Kakvoća tjestenine bogate vlaknima, obogaćene prahom kore lubenice različitih veličina čestica

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    Research background. Watermelon rind, a by-product of watermelon juice processing, contains large amounts of dietary fibre and phenols with antioxidant capacity. The use of agro-industrial by-products would both improve economic benefits and reduce environmental emissions. The aim of this research is to examine the effect of the particle size of watermelon rind powder on the quality of high-fibre pasta. Experimental approach. The nutritional, physical and physicochemical quality of three samples of watermelon rind powder, sieved through three sieves with aperture size of 400, 210 and 149 μm, were analysed. Durum wheat semolina with watermelon rind powder mass fraction of 10 % were mixed and used to make pasta. Nutritional, textural and cooking quality, sensory acceptability, in vitro glycaemic index and antioxidant bioaccessibility of high-fibre pasta with added watermelon rind powder of different particle sizes were evaluated and compared. Results and conclusions. When the sieve aperture size was reduced from 400 to 149 µm, the soluble dietary fibre and total phenolic contents of watermelon rind powder were increased by 35 and 15 %, respectively, while its insoluble dietary fibre content was decreased by 21 %. Decrease in sieve aperture size from 410 to 149 µm reduced phenolic bioaccessibility of the fortified pasta from 63 to 57 %, but enhanced its predicted glycaemic index from 50 to 69. It also decreased the pasta hardness by 13 %, but improved its elongation rate and tensile strength by 13 and 40 %, respectively. The finer the particles of the watermelon rind powder, the longer the optimal cooking time, the higher the water absorption index, and the lower the cooking loss of the supplemented pasta. Consumers did not notice any significant differences in the overall acceptability among all pasta samples. Novelty and scientific contribution. The particle size of the watermelon rind powder had a major effect on nutritional value, texture and cooking quality of the fortified pasta. In particular, the predicted glycaemic index and antioxidant bioaccessibility of high-fibre pasta were significantly affected by the particle size of the dietary fibre material used in the recipe.Pozadina istraživanja. Kora lubenice, nusproizvod prerade soka lubenice, sadržava velike količine prehrambenih vlakana i fenola s antioksidacijskim svojstvima. Korištenjem agroindustrijskih nusproizvoda poboljšala bi se ekonomska učinkovitost procesa i smanjila emisija u okoliš. Svrha je ovog istraživanja bila ispitati utjecaj veličine čestica praha kore lubenice na kakvoću tjestenine bogate vlaknima. Eksperimentalni pristup. Ispitane su nutritivna, fizikalna i fizikalno-kemijska kakvoća triju uzoraka praha kore lubenice, prosijanih kroz tri sita veličine otvora 400, 210 i 149 μm. Krupica od durum pšenice pomiješana s 10 % praha kore lubenice upotrijebljena je za izradu tjestenine. Procijenjeni su i uspoređeni sljedeći parametri: nutritivna i teksturalna kakvoća te ona nakon kuhanja, senzorska prihvatljivost, in vitro glikemijski indeks i antioksidacijska biološka raspoloživost tjestenine bogate vlaknima s dodatkom praha kore lubenice različitih veličina čestica. Rezultati i zaključci. Smanjenjem veličine otvora sita s 400 na 149 µm povećali su se udjel topljivih prehrambenih vlakana za 35 % i ukupni udjel fenola u prahu kore lubenice za 15 %, dok se udjel netopljivih prehrambenih vlakana smanjio za 21 %. Smanjenjem veličine otvora sita s 400 na 149 µm smanjila se biološka raspoloživost fenola iz obogaćene tjestenine sa 63 na 57 %, ali se njezin predviđeni glikemijski indeks povećao s 50 na 69. Također se smanjila tvrdoća tjestenine za 13 %, no poboljšala se njezina rastezljivost za 13 % i vlačna čvrstoća za 40 %. Što su čestice praha kore lubenice bile sitnije, to je dulje bilo optimalno vrijeme kuhanja, veći je bio indeks upijanja vode i manji gubitak proizvoda nastao kuhanjem. Potrošači nisu primijetili nikakve bitne razlike u ukupnoj prihvatljivosti uzoraka obogaćene tjestenine. Novina i znanstveni doprinos. Veličina čestica praha kore lubenice uvelike je utjecala na nutritivnu vrijednost, teksturu i kakvoću obogaćene tjestenine nakon kuhanja. Konkretno, veličina čestica prehrambenih vlakana u materijalu korištenom u recepturi bitno je utjecala na predviđeni glikemijski indeks i antioksidacijsku biološku raspoloživost tjestenine bogate vlaknima

    Academic Anxiety of Vietnamese Secondary School Students as a Reason for Applying Online Learning

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    Academic anxiety is one of the major problems in student psychology across the world. It applies equally to students of all ages, from elementary school to college and university students. Research shows that learning online is an effective way to defuse feelings of academic anxiety. Elimination of anxiety is clearly visible regardless of age, gender, or prior online learning experience. The study aims to identify academic anxiety as one of the most important reasons for moving to online learning or blended learning in secondary school. The study investigated academic anxiety among secondary school students in Vietnam. After surveying 677 students in classroom learning, the results showed that 13.7% of secondary students suffered from frequent anxiety, and 3.0% of them suffered from very frequent anxiety. Lower anxiety was observed among students actively participated in-class activities, and students with excellent academic performance. These factors can be optimally enhanced through blended and online learning. There were no differences in academic anxiety among male and female students, urban and rural students. There was a moderate correlation between a student's anxiety level and pressure of the school, parental expectations, students' motivation for high performance, and especially, among students who have the melancholic temperament. And the influence of these negative factors can also be optimally reduced with the help of online learning. Regression model could provide useful suggestions for parents, teachers and students in reducing academic anxiety for students, including the use of full or blended online learning

    Enzimatska obrada iskorištenih listića zelenog čaja i njihova primjena u proizvodnji čajnog peciva s velikim udjelom prehrambenih vlakana

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    Research background. By-products of food industry have been studied as sources of high fibre and antioxidant ingredients for healthy food products, because of their economic and environmental benefits. However, the soluble dietary fibre content of these materials is usually lower than the recommended value that is claimed to bring positive health effects. Enzymatic treatment could be an efficient method for modifying insoluble and soluble dietary fibre contents of these materials. The purpose of this study is to investigate the effects of enzymatic treatment conditions on soluble, insoluble and total dietary fibre mass fractions in spent green tea leaves, and evaluate the quality of dough and cookies when different mass fractions of untreated and treated leaves were added to the recipe. Experimental approach. The mass fractions of soluble, insoluble and total dietary fibre in spent tea leaf powder was evaluated after the leaves were treated with cellulase amount of 0−25 U/g for 0 to 2 h. Wheat flour was replaced by untreated and treated spent tea leaf powder at 0, 10, 20, 30 and 40% in cookie formulation. Textural properties of dough, proximate composition, physical properties and overall acceptability of cookies were analysed. Results and conclusions. The appropriate conditions for enzymatic treatment were enzyme loading of 20 U/g and biocatalytic time of 1.5 h, under which the mass fraction of soluble dietary fibre in spent tea leaves increased by 144.5% compared to that of the control sample. The addition of spent tea leaves led to the increase in dough hardness. Increase in the spent tea leaf amount also enhanced fibre mass fraction, antioxidant activity and hardness of cookies but reduced their overall acceptability. Moreover, the enzymatic treatment of spent tea leaves improved the soluble to total dietary fibre ratio of the cookies, which influenced their textural properties and health benefits. The cookies with added 20% untreated or treated spent tea leaves were overall accepted by the panel. Novelty and scientific contribution. For the first time, spent tea leaves have been treated with enzymes to improve their soluble to total dietary fibre ratio. The treated spent tea leaves are a new promising high-fibre antioxidant ingredient for cookie preparation.Pozadina istraživanja. Nusproizvodi prehrambene industrije ispituju se iz ekonomskih i ekoloških razloga kao izvori sastojaka s velikim udjelom prehrambenih vlakana i antioksidacijskim učinkom koji se mogu upotrijebiti u proizvodnji zdrave hrane. Međutim, udjel topljivih prehrambenih vlakana u nusproizvodima je obično manji od preporučenih vrijednosti koje mogu imati pozitivan učinak na zdravlje. Enzimatska obrada bi mogla biti učinkovita metoda modificiranja netopljivih i topljivih prehrambenih vlakana iz otpada prehrambene industrije. Svrha je ovog rada bila ispitati utjecaj različitih uvjeta enzimatske obrade na masene udjele topljivih, netopljivih i ukupnih prehrambenih vlakana u iskorištenim listićima zelenog čaja, te procijeniti kakvoću tijesta i čajnog peciva s dodatkom različitih masenih udjela obrađenih i neobrađenih listića. Eksperimentalni pristup. Maseni udjeli topljivih, netopljivih i ukupnih prehrambenih vlakana u prahu od iskorištenih listića zelenog čaja mjereni su nakon njihove obrade s 0–25 U/g celulaze tijekom 0 do 2 h. U smjesi za čajno pecivo je pšenično brašno zamijenjeno s 0, 10, 20, 30 i 40 % obrađenog ili neobrađenog praha iskorištenih listića zelenog čaja. Ispitani su tekstura tijesta te kemijski sastav, fizikalna svojstva i ukupna prihvatljivost dobivenog čajnog peciva. Rezultati i zaključci. Pri povoljnim uvjetima enzimatske obrade, a to su 20 U/g enzima i vrijeme trajanja biokatalitičkog procesa od 1,5 sata, maseni udjel topljivih prehrambenih vlakana u iskorištenim listićima zelenog čaja porastao je za 144,5 % u usporedbi s kontrolnim uzorkom. Dodatkom iskorištenih listića zelenog čaja povećala se tvrdoća tijesta. Povećanjem količine listića čaja povećali su se i maseni udjel vlakana, antioksidacijska svojstva i tvrdoća čajnog peciva, ali se smanjila njihova prihvatljivost. Osim toga, enzimatskom se obradom iskorištenih listića zelenog čaja poboljšao omjer topljivih i ukupnih vlakana u čajnom pecivu, što je utjecalo na njegovu teksturu i pozitivan učinak na zdravlje. Panel ocjenjivača je okarakterizirao čajno pecivo s dodatkom 20 % obrađenih ili neobrađenih iskorištenih listića čaja kao prihvatljive. Novina i znanstveni doprinos. Prvi put je enzimatskom obradom iskorištenih listića zelenog čaja poboljšan njihov omjer topljivih i ukupnih prehrambenih vlakana. Obrađeni iskorišteni listići zelenog čaja novi su obećavajući sastojak s antioksidacijskim svojstvima koji se može upotrijebiti u pripremi čajnog peciva

    Caractérisation de dispositifs de récupération d'horloge tout-optique par la mesure de taux d'erreur binaire

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    session affiches A5 « Systèmes et Réseaux de télécommunications » [A5.2]National audienceNous proposons de caractériser différentes récupérations d'horloge tout-optiques, à base de lasers auto-pulsants à semiconducteurs, par la mesure de taux d'erreur binaire à 42,66 Gbit/s. Nous utilisons pour cela une technique de remodulation de l'horloge optique qui permet, via la mesure de taux d'erreur binaire, de comparer leurs performances et de quantifier leur sensibilité à la polarisation

    High Performance and Polarisation Insensitive BER Assessment of a 42.66 Gbit/s All-Optical Clock Recovery

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    regular session Mo.3.C « Towards 100 Gb/s » [Mo.3.C.6]International audienceWe propose a Bit-Error Rate assessment, and polarisation sensitivity characterization of an all-optical clock-recovery at 42.66 Gbit/s in a system environment

    Impacts of Economic Development on the Awareness of Cultural Preservation of Ethnic Minority People in the Border Region of Northern Vietnam

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    Purpose: The aim of this study is to examine how the Vietnamese government's economic development strategies affect ethnic minority people's knowledge of cultural preservation in the border area of Northern Vietnam.   Theoretical framework: The study focuses on three main driven factors of the awareness of cultural preservation that are economic changes, societal changes, and environmental changes from three economic fields: agriculture, industry, and trade and services.   Design/methodology/approach: The research sample was taken from ethnic minorities in Northern Vietnam's border area. For questionnaire administration, interviewees are selected at random from the population. Face-to-face, drop-off, and phone-calling approaches were used to disseminate the questionnaire. We received 544 completed returns out of 725 surveys sent out. The data was then cleaned and analyzed with SPSS 20 software using Partial Least Squares Structural Equation Modelling (PLS-SEM).   Findings: The results of a study of ethnic minority communities in seven provinces in Northern Vietnam's border region show that the development of agriculture, industry, trade and service significantly impacts ethnic minority people's awareness of cultural preservation issues due to environmental changes. In contrast, economic and sociological developments appear to have little influence on ethnic minority people's attention to cultural preservation. This phenomenon may be due to the long-term effects of economic and sociological changes, which mostly affect intangible cultural heritages. In contrast, environmental impats are felt swiftly and primarily on physical cultural heritages that can be seen.   Research, Practical &amp; Social implications: The findings of the research provide policymakers with valuable insights on the effects of economic development on cultural preservation. The study's recommendations can inform policies that promote sustainable economic development while preserving the cultural heritage of ethnic minority communities.   Originality/value: The research focuses on the border region of Northern Vietnam, which is an area of strategic importance for economic development and cultural preservation. The study's unique focus on this region provides insights into the cultural and economic dynamics of a specific area that has not been extensively studied
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