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Articoli di riviste sul tema "Taux GC"
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OUAAR, Djilali, Aicha MEGHERBI BENALI, Fawzia TOUMI BENALI, Marie-France THÉVENON, Kévin CANDELIER, Luc PIGNOLET e Jean GÉRARD. "Durabilité naturelle et composition en extractibles du bois de Juniperus oxycedrus subsp. oxycedrus du Nord-Ouest de l’Algérie". BOIS & FORETS DES TROPIQUES 350 (4 gennaio 2022): 57–69. http://dx.doi.org/10.19182/bft2021.350.a36837.
Testo completoAbstract (sommario):
Les bois de Juniperus oxycedrus subsp. oxycedrus étudiés sont issus de deux provenances du Nord-Ouest algérien aux conditions climatiques et édaphiques différentes (régions de Sidi Bel Abbès et de Tiaret). Les extractibles et les polyphénols totaux du duramen ont été quantifiés et caractérisés. La durabilité naturelle du duramen a été évaluée vis-à-vis de deux champignons de pourriture brune (Rhodonia placenta et Coniophora puteana) et de termites (Reticulitermes flavipes). Les taux d’extractibles les plus élevés sont ceux obtenus pour les bois de Sidi Bel Abbès. L’extraction au mélange toluène-éthanol a permis d’obtenir des taux plus élevés que l’extraction à l’eau, respectivement 14,17 % et 1,35 % pour les bois de Sidi Bel Abbès contre 9,84 % et 1,19 % pour ceux de Tiaret. Les analyses par chromatographie en phase gazeuse couplée à la spectrométrie de masse (GC/MS) montrent que les familles chimiques majoritairement identifiées dans les extraits aqueux sont les sesquiterpénoïdes, les acides gras et les stérols. Dans les extraits au toluène-éthanol, les sesquiterpènes et les sesquiterpénoïdes sont les composés majeurs. La composition en sesquiterpènes et sesquiterpénoïdes est différente en fonction de la provenance des bois, mais reste très similaire quantitativement. La teneur en polyphénols totaux des extraits au méthanol de la provenance Sidi Bel Abbès est supérieure à celle de Tiaret. Aucune différence significative n’est observée entre les deux provenances pour la durabilité naturelle vis-à-vis de C. puteana. En revanche, la résistance à R. placenta est significativement plus élevée pour la provenance Sidi Bel Abbès. Pour les deux provenances, le bois de J. oxycedrus subsp. oxycedrus est très durable vis-à-vis des champignons de pourriture. Il est aussi répulsif et résistant aux attaques de termites. Une analyse ciblée des relations entre la composition chimique et la durabilité naturelle permettra de mettre en évidence la nature du ou des constituants responsables de la durabilité́ naturelle du bois de J. oxycedrus subsp. oxycedrus, tant vis-à-vis des champignons lignivores que des termites.
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Eddine, Laib Djamel, Benzehra Abdelmadjid, Rahmani Youcef, Boulaouad Belkacem Aimene e Akkal Salah. "L’emploi de l’extrait du champignon endophyte Aspergillus niger isolé à partir des feuilles du ricin commun Ricinus communis L. (Euphorbiaceae, Malpighiales) comme agent de lutte biologique contre le criquet migrateur Locusta migratoria L. (Oedipodinae, Acrididae)." Journal of Applied Biosciences 170 (28 febbraio 2022): 17720–38. http://dx.doi.org/10.35759/jabs.170.5.
Testo completoAbstract (sommario):
Objectifs : Évaluer l'activité insecticide de l'extrait du champignon endophyte Aspergillus niger. Méthodologie et Résultats : Pour évaluer l'activité insecticide, dix concentrations (de 0,2 à 2 g/ L) de l'extrait fongique ont été appliqués par contact et par ingestion contre Locusta migratoria L. Pour connaitre la nature des métabolites secondaires responsables de l’activité insecticide des analyses chimiques, infrarouge à réflexion totale atténuée par transformée de Fourier de l'extrait fongique et un GC-MS-MS des hyphes du champignon et de l'extrait fongique ont été effectués. Un test d’inhibition d’Acétyl cholinestérase par l’extrait fongique a été effectué afin de connaitre le mode d’action ou l’effet d’extrait sur le système nerveux des insectes traités. La concentration la plus efficace contre les insectes est de 2 g/L, avec un taux de mortalité maximum de 86,95%et 100% pour les traitements par contact et ingestion, respectivement. L'analyse chimique de l'extrait fongique a révélé la présence de polyphénols, d'alcaloïdes, de terpénoïdes et de saponines comme métabolites responsables de ces activités. L'analyse FTIR-ATR de l'extrait fongique a révélé la présence de groupes alcool, nitro, imine, alcyne et hydroxyle. L'analyse GC-MS des hyphes et de l’extrait fongique a révélé la présence des volatiles insecticides Hexahydro-1H-cyclopenta [c] isoxazole-4, 5,6-triol, 2, 3, 4,4a, 5, 6, 7,8-octahydro-1H -naphtalène-1,8a-diol et acide propanoïque 2-éthyl-3-hydroxyhexyle. A 4 μg/mL l’extrait fongique est doté d’une activité inhibitrice d’Acétylcholinestérase maximale de 73,91 %. Conclusions et application des résultats : l’extrait du champignon endophyte d’Aspergillus niger constitue une bonne source de métabolites secondaires volatiles et non-volatiles à activité insecticide et peut être utilisé comme insecticide de contact ou ingestion contre L. migratoria. 17720 Laib et al., J. Appl. Biosci. Vol : 170, 2022 L’emploi de l’extrait du champignon endophyte Aspergillus niger isolé à partir des feuilles du ricin commun Ricinus communis L. comme agent de lutte biologique contre le criquet migrateur Locusta migratoria L. Mots clés : Activité insecticide, champignons endophytes, Locusta migratoria, Aspergillus niger, GC-MS-MS, FTIR-ATR. ABSTRACT Objectives: Evaluate the insecticidal activity of the extract obtained from the endophytic fungus, Aspergillus niger. Methodology and Results: Ten concentrations of 0.2 to 2 g/L of the fungal extract were applied by contact against Locusta migratoria L. To find out the nature of the secondary metabolites responsible for the insecticidal activity, we carried out chemical analysis, an infrared analysis with total reflection attenuated by transform Fourier of the fungal extract, and GC-MS-MS analysis for both colony and fungal extract. To reveal the effect of the extract on the nervous system of the treated insects, we carried out an acetyl cholinesterase inhibition test. The most effective concentration against the insects was 2 g/L, with a maximum mortality rate of 86, 95%and 100% for L. migratoria upon contact and ingestion treatments, respectively. Chemical analysis of the fungal extract revealed the presence of polyphenols, alkaloids, terpenoids, and andsaponins asthe metabolites responsible for these activities. The FTIR-ATR of the fungal extract revealed the presence of alcohol, nitro, imine, alkyne, and hydroxyl groups. Specifically, GC-MS analysis of both colony and fungal extract revealed the presence of the insecticidal volatiles Hexahydro-1Hcyclopenta [c] isoxazole-4,5,6-triol ,2,3,4,4a, 5,6,7,8-octahydro-1H-naphthalene-1,8a-diol and Propanoic acid 2-ethyl-3-hydroxyhexyl.Moreover, we found that at a concentration of 4 μg/mL, the fungal extract had a maximum inhibitory capacity of Ache of 73.11%. Conclusions and application of findings: the endophytic fungus A. niger is a good source of volatile and non-volatile secondary metabolites with insecticidal activity against L. migratoria. Keywords: Insecticidal activity, endophytic fungi, Locusta migratoria, Aspergillus niger, GCMS-MS, FTIR-ATR.
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Awaludin, Zaenal, Masatoshi Suzuki, Jahangir Masud, Takeyoshi Okajima e Takeo Ohsaka. "Enhanced Electrocatalysis of Oxygen Reduction on Pt/TaOx/GC". Journal of Physical Chemistry C 115, n. 51 (6 dicembre 2011): 25557–67. http://dx.doi.org/10.1021/jp209347r.
Testo completo
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Sidhu, A., A. Bharadwaj e A. Nandagudi. "AB0529 TEMPORAL ARTERY ULTRASOUND (TAUS) IS A RELIABLE TECHNIQUE TO RULE OUT GCA EVEN IN THE LEARNING PHASE". Annals of the Rheumatic Diseases 79, Suppl 1 (giugno 2020): 1562.3–1562. http://dx.doi.org/10.1136/annrheumdis-2020-eular.6540.
Testo completoAbstract (sommario):
Background:Giant cell arteritis (GCA) is an emergency. The initial treatment with high dose glucocorticoids (GC) is often started on clinical suspicion without waiting for Temporal artery biopsy (TAB) results, which can take days to be available. TAUS is a simple, non-invasive test which is readily available. However, like any other ultrasound, it is also operator dependent. A positive halo sign is the most specific abnormality seen on TAUS in GCA patients. The percentage of false positive TAUS in GCA diagnosis is low (1), but it can result in over diagnosis and unnecessary exposure to high dose GC in elderly population.Objectives:We looked at the reliability of TAUS in ruling out GCA after it was introduced within our rheumatology department one year ago.Methods:We adopted the quality improvement methodology for assessment. Retrospective data of suspected GCA patients was collected over the last two years. TAUS was introduced regularly to the investigative plan after eleven months. Two Rheumatology consultants were trained in TAUS. Results were compared before and after the introduction of ultrasound as a diagnostic tool. In collecting the data, our main focus for documentation was based on clinical symptoms, TAUS and TAB results. We aimed to increase the awareness of appropriate GCA referrals among the primary and secondary care with the support of teaching sessions.Results:From January 2018 to November 2019, 101 patients were referred to rheumatology with suspected GCA. Median age of our cohort was 72 years with male to female ratio of 1:3. 35 patients were referred in the first 11 months out of which, 10 (28.6%) were diagnosed with GCA. TAUS and TAB was done in 20% and 49% of patients respectively. 66 patients were referred in the next 12 months after TAUS was introduced. Out of 66, 14 patients (21.2%) were diagnosed as GCA. TAUS and TAB were done in 82% and 38% of the patients respectively. As listed in table 1, only 1 patient was found to have positive TAB after a negative TAUS (false negative). All of patients with positive TAUS were treated as GCA on the basis of clinical grounds, irrespective of TAB results. Despite the regular use of TAUS as a diagnostic tool in the second phase, there is a higher percentage of patients (78.8%) in which GCA was ruled out.TAUS introductionBefore regular TAUS(Jan 2018 – Nov 2018)After regular TAUS(Dec 2018 – Nov 2019)Patients referred3566GCA10 (28.6%)14 (21.2%)Not GCA25 (71.4%)52 (78.8%)TAUS done in20%82%TAB done in49%38%TAUS -ve and TAB +ve01TAUS +ve and TAB -ve/not done28Conclusion:After the routine introduction of TAUS, the percentage of patients diagnosed with GCA has declined and clinicians have been able to exclude suspected GCA diagnosis in a larger proportion of patients referred. This is noteworthy as our Rheumatologists are still in the learning phases of determining the significance of utility of TAUS. There is only a small decline in TAB frequency, which is expected to go down further in the coming years. We also noticed that the number of patients referred has almost doubled. This might be due to better education and awareness at the primary and secondary care level which was done as part of the project.References:[1]Fernández E, Monjo I, Bonilla G, et alOP0210 FALSE POSITIVES OF ULTRASOUND IN GIANT CELL ARTERITIS. SOME DISEASES CAN ALSO HAVE HALO SIGNAnnals of the Rheumatic Diseases2019;78:181Disclosure of Interests:None declared
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Wilson, Karen L. "Report of the General Committee: 26". TAXON 72, n. 4 (agosto 2023): 905–7. http://dx.doi.org/10.1002/tax.12994.
Testo completoAbstract (sommario):
SummaryDecisions of the General Committee are reported on about half of the proposals and requests in Report 73 of the Permanent Nomenclature Committee for Vascular Plants and Report 16 of the Permanent Nomenclature Committee for Fossils. As specified by the Code, the GC was consulted by the NC Fungi on several matters relating only to fungi.
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Thompson, M. G., R. M. Palmer, A. Thom, K. Garden, G. E. Lobley e G. Calder. "N tau-methylhistidine turnover in skeletal muscle cells measured by GC-MS". American Journal of Physiology-Cell Physiology 270, n. 6 (1 giugno 1996): C1875—C1879. http://dx.doi.org/10.1152/ajpcell.1996.270.6.c1875.
Testo completoAbstract (sommario):
A method that employs gas chromatography-mass spectrometry has been developed to measure N tau-methylhistidine (3-methylhistidine; 3-MH) synthesis and release from skeletal muscle myotubes in vitro. It shows excellent linearity (0.9999) over the range studied (0-4 nmol), high recovery (92.6%), and low coefficient of variation (1.6%). 3-MH release from myotubes was essentially linear over a 96-h incubation, whereas the loss of 3-MH from cell protein accelerated with increasing time, an effect due, at lest in part, to decreasing rates of total protein synthesis. When incubated in either glutamine-free or methionine-free medium for 48 h, 3-MH in cell protein and appearing in the medium were greatly reduced compared with the 48-h controls, suggesting that hypertrophy was greatly reduced. Similar but lesser trends were observed with adenosine 3',5' -cyclic monophosphate. In contrast, 12-O-tetradecanoylphorbol-13-acetate (TPA) appeared to both stimulate 3-MII synthesis and inhibit its release during a 48-h incubation. The development of this method facilitates detailed investigation into the mechanisms through which agents such as TPA regulate myofibrillar protein degradation.
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Silva, Bruno B., Pedro L. Rosalen, Jaime A. Cury, Masaharu Ikegaki, Vinícius C. Souza, Alessandro Esteves e Severino M. Alencar. "Chemical Composition and Botanical Origin of Red Propolis, a New Type of Brazilian Propolis". Evidence-Based Complementary and Alternative Medicine 5, n. 3 (2008): 313–16. http://dx.doi.org/10.1093/ecam/nem059.
Testo completoAbstract (sommario):
Red propolis is a new type of Brazilian propolis. This material, as well as the secretions of 20 plant species that are often mentioned as its probable botanical source, have been investigated by RP-HPTLC. Phytochemical evidence based on UV-VIS spectra, RP-HPLC and GC-MS, showedDalbergia ecastophyllum(L.) Taub. to be the main source of red propolis in Alagoas state. The propolis and plant resin showed high relative percentages of the isoflavonoids 3-Hydroxy-8,9-dimethoxypterocarpan and medicarpin. To our knowledge this is the first report of the secretion of a leguminous species being the source of propolis.
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Tyutkova, Ekaterina Aleksandrovna, Sergey Radzhinaldovich Loskutov e Daniil Vyacheslavovich Dorzhiev. "SEASONAL CHEMICAL STRUCTURE VARIABILITY IN BETULA TORTUOSA LEDEB. TREE RINGS IN ALPINE FOREST-TUNDRA OF KUZNETSK ALA TAU MOUNTAINS". chemistry of plant raw material, n. 3 (2 ottobre 2023): 63–70. http://dx.doi.org/10.14258/jcprm.20230311761.
Testo completoAbstract (sommario):
Woody vegetation growth conditions have marked effects on hemicellulose, cellulose and lignin formation. In this study, we analyzed the climatic responses of these major cell wall polymers in Betula tortuosa. We studied 35 annual rings (1980–2015) of Betula Tortuosa Ledeb. trees growing in the alpine forest-tundra of Kuznetsk Ala Tau using and pyrolysis gas chromatography mass spectrometry (Py-GC/MS). Our analysis of the correlation of the resulting spectra and Py-GC/MS values with mean air temperature and precipitation showed that the polymeric composition of Betula Tortuosa Ledeb. was mainly determined by June-August climate. The major factor limiting the development of the “unique” cell wall polymer composition of Betula Tortuosa Ledeb. found in alpine forest-tundra of Kuznetsk Ala Tau was a deficit of heat. At the end of the growing season, precipitation had largely a negative impact on polymer formation in Betula Tortuosa Ledeb. cell walls. We believe that Py-GC/MS is an effective approach to quantifying the consequences of current climate trends for Siberian forest ecosystems.
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Firdaus, Aulia Anisa, Endhah Purwandari, Retno Asih, Ahmad Sholih e Darminto Darminto. "The Optical Energy Gap of the Semiconducting Intrinsic Layer for Organic Solar Cell Applications". Computational And Experimental Research In Materials And Renewable Energy 6, n. 1 (31 maggio 2023): 14. http://dx.doi.org/10.19184/cerimre.v6i1.39254.
Testo completoAbstract (sommario):
The optical energy gap of the semiconducting intrinsic layer plays a crucial role in determining the increase in efficiency. The carbon-based biomass can be a choice for the silicon used as solar cell material. Here, we proposed the best biomass that can be used as a semiconductor component in solar cell applications. Coconut shells as bio-waste and palmyra sap, which are available in most areas of Indonesia, can be the best candidates to be considered. The XRD measurement showed both organic materials have an amorphous phase. The coconut shells sample has two peaks that are identical to graphene peaks, therefore this material is called graphenic-like carbon (GC). Furthermore, from the UV-visible spectroscopy, it was shown that both materials have a high transmittance of more than 95%, which indicates that they have transparent properties. Also, the Tauc plot method gives information about the optical energy gap of coconut shell charcoal (GC) and palmyra sap (a:C) which are 2.67 and 1.83 eV, respectively. From this result, palmyra sap becomes promising material to be applied as an intrinsic layer for semiconducting components in solar cell applications.Keywords: Amorphous phase, Coconut shells charcoal, Optical energy gap, Palmyra sugar.
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Ambastha, Surabhi, Amit Patnaik, Vinay Oraon e Latika Sharan. "Antimicrobial activity and GCMS Analysis of leaves Extracts of Butea Monosperma Lam Taub". Defence Life Science Journal 8, n. 3 (29 maggio 2023): 217–28. http://dx.doi.org/10.14429/dlsj.8.18789.
Testo completoAbstract (sommario):
Butea monosperma (Lam.) Taub is a well-known medicinal plant belonging to the family Fabaceae. More than hundreds of plants have been reported in the Ethno-botanical literature of India for theiranti-microbial activity as well as for treatment of many diseases and Butea monosperma (Lam.)Taub is one of them. The present investigation is focused on the anti-microbial activity of Butea monosperma leaves against both gram-positive (Bacillus subtilis, Enterococcus faecalis, Lactobacillus acidophilus, Staphylococcus aureus and Streptococcus mutans) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) as well as fungi (Candida albicans and Trichophyton rubrum). Both excerpts (ethanol and methanol) show positive responses against all the selected microorganisms. GC-MS analysis is done to find out important compound which is anti-microbial. A total of 38 compounds are identified in GC-MS analysis. Out of 38 compounds, 8 compounds are identified as antimicrobial in nature such as Dodecane, 2-HEXADECEN-1-OL, 3,7,11,15-TETRAMETHYL-, [R-[, Hexadecanoic acid, methyl ester, Phytol, Palmidrol, Squalene, Tetracosane, Vitamin E and Lup-20(29)-en-3-one which justify, this plant possess significant anti-microbial property. GC-MS analysis reveals that majorly, this plant leaves also possess 10 antioxidant compounds (Neophytadiene, 2-HEXADECEN-1-OL, 3,7,11,15-TETRAMETHYL-, [R-[, n-Hexadecanoic acid, Phytol, squalene, .alpha.-Tocospiro B, Tetracosane, .gamma.-Tocopherol, Ergost-5-en-3-ol, (3.beta.)- and STIGMASTA-5,22-DIEN-3-OL, (3.BETA.,22E)-,), 9 anti-cancerous compounds (Hexadecanoic acid, methyl ester, 9,12,15-OCTADECATRIENOIC ACID, METHYL ESTER, squalene, .gamma.-Tocopherol, Vitamin E, Ergost-5-en-3-ol, (3.beta.)-, STIGMASTA- 5,22-DIEN-3-OL, (3.BETA.,22E)-, .gamma.-Sitosterol and Lupeol),8 anti-inflammatory compounds (Neophytadiene,2-HEXADECEN-1-OL, 3,7,11,15-TETRAMETHYL-, [R-[, Hexadecanoic acid, methyl ester, n-Hexadecanoic acid, 9,12,15-OCTADECATRIENOIC ACID, METHYL ESTER, Phytol, Palmidrol, .alpha.-Tocospiro B and Lupeol), 3 cardioprotective compounds ( Neophytadiene, .alpha.-Tocospiro B and .gamma.-Tocopherol A) and 5 antidiabetic compounds (.alpha.-Tocospiro B, Vitamin E, STIGMASTA-5,22-DIEN-3-OL, (3.BETA.,22E)-, .gamma.-Sitosterol and Lup-20(29)-en-3-one).This investigation suggests that this plant leaf has not only anti-microbial potential but also possesses other important compounds to fight against many deadly diseases. Thus, this plant has immense potential to make an individual place in pharmacological industries, especially as antibiotics.
Tesi sul tema "Taux GC"
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Rousselle, Marjolaine. "Estimation et analyse du taux de substitution adaptatif chez les animaux". Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTG040/document.
Testo completoAbstract (sommario):
Comprendre les déterminants du taux d’adaptation est une question primordiale en évolution moléculaire. En particulier, l’influence de la taille efficace de population sur la sélection positive, ainsi que la nature des changements d’acides aminés qui mènent à de l’adaptation sont des questions encore débattues. Pour y répondre, la méthode DFE-α, dérivée du test fondateur de McDonald & Kreitman, est un outil puissant pour mesurer le taux de substitution adaptatif. Elle est néanmoins sensible à certains biais. Au cours de cette thèse, nous avons identifié deux biais majeurs de cette méthode, les fluctuations de long-terme du régime de sélection-dérive via des fluctuations démographiques, et la conversion génique biaisée vers GC (gBGC). Via des simulations, nous avons montré que divers scénarios plausibles de fluctuations démographiques peuvent mener à une sur-estimation du taux de substitution adaptatif. Nous avons aussi obtenu des indications empiriques que le régime de sélection-dérive récent ne reflète pas le régime de sélection-dérive de long-terme chez diverses espèces animales, ce qui représente une violation d’une hypothèse forte de la méthode DFE-α. D’autre part, nous avons montré que la gBGC entraîne une sur-estimation du taux de substitution adaptatif chez les primates et les oiseaux. Via un jeu de données de neuf taxons de métazoaires et un total de 40 espèces, nous avons d’une part initié une analyse visant à identifier la nature des changements d’acides aminés qui mènent à l’adaptation, et montré que les changements radicaux sont soumis à une plus forte sélection purificatrice que les changements conservatifs. D’autre part, nous avons pu évaluer le lien entre la taille efficace et le taux de substitution adaptatif tout en prenant en compte les deux sources de biais explorées précédemment. Nous avons mis en évidence pour la première fois une relation négative entre le taux de substitution adaptatif et des traits d’histoire de vie représentatifs de la taille de population de long-terme. Ce résultat va à l’encontre de l’hypothèse canonique d’une adaptation plus efficace en grandes populationsUnderstanding the determinants of the adaptive substitution rate is a central question inmolecular evolution. In particular, the influence of the effective population size N e on positiveselection as well as the nature of amino acid changes that lead to adaptation are still debated. TheDFE-α method, which was derived from the seminal McDonald & Kreitman test, is a powerful toolfor estimating the adaptive substitution rate. However, it is sensitive to various sources of bias. Inthis thesis, we identified two major sources of bias of this test, long-term fluctuations of theselective-drift regime through demographic fluctuations, and GC-biased gene conversion (gBGC).Using simulations, we showed that under plausible scenarios of fluctuating demography, the DFE-αmethod can lead to a severe over-estimation of the adaptive substitution rate. We also showed thatpolymorphism data reflect a transient selective-drift regime which is unlikely to correspond to theaverage regime experienced by genes and genomes during the long-term divergence betweenspecies. This violates an important assumption of the DFE-α method. Our results also indicate thatgBGC leads to an over-estimation of the adaptive substitution rate in primates and birds. Using adataset of nine metazoan taxa for a total of 40 species, we started an analysis aiming at identifyingthe type of amino acid changes that are more prone to adaptation, and evaluated the link between N eand the adaptive substitution rate while accounting for the two sources of bias previously explored.We reveal for the first time a negative relationship between the adaptive substitution rate and life-history traits representative of long-term N e . This result is in contradiction with the widespreadhypothesis that adaptation is more efficient in large populations
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Roginski, Paul. "Emergence de peptides de novo à partir de régions non-codantes". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASL063.
Testo completoAbstract (sommario):
Le génome codant et le génome non-codant ont été présentés comme deux espaces bien délimités. Pourtant les technologies « omiques » ont révélé un passage du non-codant vers le codant. La majeure partie du génome non-codant peut être transcrite, et certains de ses transcrits sont traduits en peptides. Si l'existence de ces derniers est le plus souvent éphémère, quelques-uns peuvent être sélectionnés et fixés par l'évolution. Les gènes dont ils sont issus sont appelés « de novo ». Durant cette thèse, j'ai développé des méthodes et de nouvelles métriques pour leur identification in silico chez les eucaryotes, et ai évalué l'impact des méthodes employées sur le type de séquences retenues. J'ai aussi investigué l'influence de la composition d'un génome en bases GC sur le processus d'émergence de novo. Ce paramètre qui sous-tend le matériel nucléotidique, impacte la fréquence des codons encodés dans le génome non-codant. J'ai montré comment le code génétique permet d'articuler ces contraintes nucléotidiques avec les contraintes protéiques (repliabilité, interactabilité). À partir des séquences ancestrales ayant donné naissance aux peptides de novo, j'ai cherché à mieux comprendre comment s'opère la transition entre les mondes non-codant et codant. Ceci m'a permis de proposer un modèle universel d'émergence des gènes de novo dicté par la structure du code génétique et le taux GC du génomeThe coding genome and the non-coding genome were presented as two well-defined spaces. However, omics technologies have revealed a passage from non-coding to coding genomes. Most of the non-coding genome can be transcribed, and some of these transcripts are translated into peptides. While the existence of peptides is usually ephemeral, some can be selected and fixed by evolution. The genes from which they are derived are called "de novo". During this thesis, I developed methods and new metrics for their in silico identification in eukaryotes, and assessed the impact of the methods employed on the type of sequences selected. I also investigated the influence of a genome's GC base composition on the de novo emergence process. This parameter, which underlies the nucleotide material, impacts the frequency of codons encoded in the non-coding genome. I have shown how the genetic code articulates these nucleotide constraints with protein constraints (foldability, interactability). Using the ancestral sequences that gave rise to de novo peptides, I sought to better understand how the transition between the non-coding and coding worlds takes place. This has enabled me to propose a universal model of de novo gene emergence dictated by the structure of the genetic code and the GC content of the genome
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Yuan, Jun. "Approche métagénomique pour l'étude de la dégradation de la quinoléine dans les sols". Phd thesis, Ecole Centrale de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00955925.
Testo completoAbstract (sommario):
Grâce au développement des technologies de métagénomique au cours des dix dernières années, il a été constaté que les micro-organismes représentent la plus grande ressource de diversité métabolique et génétique sur Terre. En effet, un gramme de sol contient 109 cellules bactériennes et 103-104 différentes espèces bactériennes. Certaines sont en mesure de réaliser des réactions enzymatiques conduisant à la dégradation complète de certains polluants toxiques pour l'environnement comme les composés organiques tels que la quinoléine. Cependant, l'immense réservoir de molécules et enzymes microbiennes n'a pas encore été exploité, car plus de 99% d'entre elles ne sont, pour l'instant, pas cultivables in vitro. Mon travail s'inscrit dans le cadre d'une collaboration entre l'Université SJTU (Shanghai Jiao Tong Université en Chine) et le groupe de G. M.E (Génomique Microbienne Environmentale) du laboratoire Ampère à l'Ecole Centrale de Lyon. Nos partenaires à l'Université SJTU ont construit un réacteur de dénitrification à l'échelle du laboratoire capable de dégrader la quinoléine en retirant la demande chimique en oxygène. Un nouvel outil appelé "Genefish" a été developpé dans notre laboratoire comme une méthode alternative de la métagénomique pour aider à la découverte de nouveaux gènes d'intérêt industriel ou environnemental. A la suite des premiers travaux réalisés dans notre laboratoire, ma thèse présentée ici comporte deux parties.Dans la première partie de ce travail, nous avons étudié le potentiel de dégradation de la quinoléine présente dans les bactéries d'un sol de référence largement étudié au laboratoire. Pour cela nous avons mis en place des expériences de microcosme qui visent à révéler la diversité potentielle des bactéries responsables de la dégradation de la quinoléine. Des analyses comparatives des profils RISA (Ribosomal Intergenic Spacer analysis) nous ont permis de mettre en évidence des changements dans la structure de la communauté des bactéries du sol incubé en conditions aérobie et anaérobie en présence de quinoléine. La dégradation de la quinoléine a été confirmée par technique de GC/MS (Gas Chromatography-Mass Spectrometry). Les travaux futurs seront de vérifier la communauté de bactéries responsables de la dégradation de quinoléine en utilisant la technique de NGS (Next Generation Sequencing).Le deuxième objectif de ma thèse a été d'utiliser Genefish dont la finalité est de capturer des gènes ciblés (le gène bcr qui serait responsable de la degradation de quinoléine dans le réacteur de nos partenaires) dans l'ADN métagénomique extrait du sol. Genefish consiste à élaborer une souche d'E.coli incluant un plasmide de capture permettant de pêcher les gènes recherchés dans un échantillon d'ADN metagénomique par recombinaison homologue. Le plasmide de capture comprend une cassette de deux gènes toxiques pour la souche qui activés par induction chimique vont permettre la sélection positive directe des clones recombinants, et deux sites multiples de clonage dans lesquels sont insérées les zones de recombinaison qui vont jouer le rôle d'hameçons. Nous avons testé la capacité de Genefish à capturer des produits PCR du gène bcr, l'efficacité de recombinaison reste faible à cause de la persistance de plusieurs copies du plasmide suicide dans la cellule après l' évenement de recombinaison. Par conséquent, trois stratégies ont été essayées pour améliorer l'efficacité: la co-électroporation, la ségrégation de plasmide et la construction de plasmide suicide en mono-copie. Finalement, la stratégie de la ségrégation plasmidique fonctionne mais l'efficacité de recombinaison est encore trop faible peut-être due à l'incertitude des modèles de recombinaison homologue. Les travaux futurs se concentreront sur l'amélioration des fréquences de recombinaison par transfert de fragments du plasmide de capture dans le chromosome de la souche Genefish.
4
Cheng, Ming-Te. "Methods for multi-class segmentation of molecular sequences". Thèse, 2006. http://hdl.handle.net/1866/16709.
Testo completoLibri sul tema "Taux GC"
1
Ulberg, Cy. Local option commercial parking tax analysis: Final report, Research Project GC 8719, Task 30, Parking Tax Evaluation. Olympia, Wash: Washington State Dept. of Transportation, Washington State Transportation Commission in cooperation with U.S. Dept. of Transportation, Federal Highway Administration, 1992.
Cerca il testo completoAtti di convegni sul tema "Taux GC"
1
Durau, Carmen Claudia, Ana Codruta Chis, Adalbert Okros e Casiana Doina Mihut. "FLORISTIC COMPOSITION AND FODDER VALUE OF SOME COMMUNAL PASTURES OF TIMIS COUNTY, ROMANIA: (A CASE STUDY)". In 23rd SGEM International Multidisciplinary Scientific GeoConference 2023. STEF92 Technology, 2023. http://dx.doi.org/10.5593/sgem2023/5.1/s20.16.
Testo completoAbstract (sommario):
Agri-fodder value, i.e., the diversity of floristic composition of communal pastures in Romania is strongly affected by impropper management practiced for the last three decades. Most permanent grassland areas are excessively grazed in addition to the effect of climate change on the multiplication and development of plant species making up the grassy cover. Communal pastures are the most important source of feed for animal growers in the territorial administrative units (TAUs) of the Timis County. Their current state is strongly correlated with grazing practices, with the maintenance of floristic composition, and their improvement methods. The goal of this paper is to illustrate ( from the perspective of floristic composition and of fodder value) the evolution of some communal pastures from Timis County. The study was carried out during three years (2020-2022) on several permanent grasslands belonging to the same TAUs. The Research method used is that of the double meter which points out biodiversity (the Shannon-Weaver Index H�, pastoral value PV, and grazing capacity Gc. Correlating these parameters allowed the authors to draw conclusions on the impact of management on vegetation and fodder value of the pastures studied. The results thus obtained are useful for the design of management strategies and for the development of some prediction models regarding the evolution of the grassy cover and of the agri-fodder value in the studied perimeter.
2
Diaz, S., N. Al Hammadi, A. Seif El Nasr, F. Villasuso, S. Prakash, O. Baobaid, D. Gracias e R. Mills. "Green Corridor: A Feasible Option for the UAE Decarbonization Pathway, Opportunities & Challenges". In ADIPEC. SPE, 2023. http://dx.doi.org/10.2118/216033-ms.
Testo completoAbstract (sommario):
Abstract The global energy sector is shifting towards a more sustainable, environmentally friendly production, and consumption of all energy sources. Climate change and ESG (Environment, Social, and Governance) topics are opening important debates about its challenges towards energy transition, management of a wide range of stakeholders, as well as benefits and opportunities, reflected on the long-term prospects of a company, which takes into consideration environmental concerns, businesses’ financial performance, resilience, and the ability to sustain their operations & business continuity during adverse situations with appropriate and effective governance frameworks. The objective of this paper is to examine the potential of green corridors (‘GC’) as a solution to reduce emissions in the shipping and logistics sector and how it aligns with the decarbonization strategy of the UAE. The scope of the proposed paper includes a pre-feasibility assessment of two locations, potential decarbonization clusters, or ports that include technical, economic, regulatory, and government aspects (e.g., consortium or JV structures). Our study will employ a mixed-methods approach, which includes a literature review, data analysis, stakeholder mapping, and expert interviews. The literature review will examine current research on decarbonization efforts in the shipping and logistics sector, with a focus on initiatives aimed at reducing greenhouse gas emissions as a tool to support the energy transition. The data analysis will be used to evaluate the pre-feasibility of implementing a GC, assessing one location and potential clusters, including project baselining for corridors, value chain mapping, screening criteria (selection framework and justification), and stakeholders’ mapping including regulatory bodies and governments. Expert interviews will be conducted with stakeholders in the shipping industry and governmental entities to gain insights into their perspectives on the potential of GC as a decarbonization pathway. GCs are increasingly seen as an essential part of the solution, viewed as catalysts to the transition toward zero-carbon shipping. Whilst there have been announcements to implement, there is no GC in full operation today, which enhances the novelty of this topic. GCs are expected to be built with decarbonization hubs to address the company's Sustainable Development Strategy (SDS) by providing carbon-free options between ports and with an end-to-end centric approach, where financing options, alternative fuels, and collaboration among sectors are essential. Moreover, GCs are expected to lower risks, increase stakeholder confidence in investing, and align on a roadmap for a multisector approach and governance structure feasible for meeting decarbonization targets and timelines. Shipping and logistics sectors represent 5-10% of direct emissions and a relevant proportion of scope 3 for the upstream & downstream sectors. Emissions and stakeholders need to be assessed, quantified, and mapped at the ports or hubs, including storage facilities, and routes. Nevertheless, identifying green policies could help close the gap in fuel costs (e.g., carbon exchanges, carbon credits, tax and fiscal policies, CCS, alternative fuel, and infrastructure incentives/subsidies, etc.), cargo sensitivity, and technology developments. The results of the paper are expected to indicate that GCs have the potential to significantly reduce greenhouse gas emissions (GHG) in the shipping and logistics sector and support the UAE's position as a "first mover" nation in terms of decarbonization. The UAE sustainability plans, and International Maritime Organization's (IMO) stricter regulations are incentivizing the sector to meet ambitious goals by 2030 and 2050, guiding more efforts to promote more collaboration across its hydrocarbon value chain. However, it will also require a significant investment in infrastructure and technology, as well as cooperation among multiple stakeholders, including government, industry, and the international community. Also, governance models and clear roadmaps linked with government policies and incentives would be important to make it successful.