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N-alkanes to estimate voluntary forage intake of cattle using controlled-release capsules; N-alcanos para estimar o consumo voluntário de forragem em bovinos usando cápsulas de liberação controlada

OLIVEIRA, Dimas Estrasulas de; MANELLA, Marcelo de Queiroz; TEDESCHI, Luis Orlindo; SILVA, Sila Carneiro da; LANNA, Dante Pazzanese Duarte
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica
Português
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N-alkanes have been used as internal markers in digestibility trials with ruminants and non-ruminants for more than 20 years. In this study, two trials were conducted under different feeding regimes to (i) evaluate the release rate of n-alkanes of controlled-release capsules in the rumen of rumen-cannulated steers either grazing or restrained in metabolic stalls and (ii) estimate voluntary forage intake of the same steers in metabolic stalls. Six rumen-cannulated Nelore steers were allocated to individual metabolic stalls and were fed diets with varying forage to concentrate ratios (80:20, 60:40, and 40:60; respectively). Corn silage was the only forage source. In the grazing trial, the same steers were evaluated under three feeding managements (Brachiaria brizantha cv. Marandu unsupplemented or supplemented with either 0.3% or 0.6% of live weight of a concentrate). The release rate of the n-alkanes (mg d-1) was measured by multiplying the distance (mm d-1) the capsule plunger travelled after 3, 7, 10, 13, and 17 d of rumen infusion to the n-alkanes concentration of capsule tablets (mg mm-1). There was an effect of day of measurement (P < 0.05) on the release rate of animals restrained in metabolic stalls and grazing. However, no effect (P > 0.05) of feeding management or feeding management x day of measurement interaction was observed. Values averaged 6.9 and 14.8%...

Uso da técnica de n-alcanos para medir o aporte de nutrientes através de estimativas do consumo de forragem em bovinos. ; The use of n-alkanes technique to measure nutrient uptake through forage intake estimates in bovines.

Oliveira, Dimas Estrasulas de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 12/09/2003 Português
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Os n-alcanos têm sido utilizados como indicadores em estudos de estimativas de consumo e composição botânica e/ou morfológica da dieta com ruminantes domésticos, selvagens e com animais não ruminantes. Foram realizados três experimentos, sendo que no primeiro foram avaliados a taxa de liberação de n-alcanos fornecidos via cápsulas de liberação controlada em animais fistulados no rúmen, alojados em gaiolas de metabolismo e, a validação da estimativa de consumo de forragem pelos animais submetidos a três tratamentos variando a relação volumoso : concentrado. No segundo foi avaliada a taxa de liberação de n-alcanos fornecidos via cápsula de liberação controlada com os mesmos animais em pastagem submetidos a três tratamentos com suplementação concentrada. As taxas foram medidas com o auxílio de um paquímetro removendo-se a cápsula via fístula ruminal, medindo-se a distância percorrida pelo êmbolo da cápsula que pressiona as pastilhas que contêm o indicador aos 3, 7, 10, 13 e 17 dias após a colocação no rúmen. Não houve efeito de dieta e da interação dieta e dia de medida (P>0,05) sobre a taxa diária de liberação no rúmen tanto com os animais em gaiolas de metabolismo como em pastagem. Foi possível unir as equações geradas em cada experimento resultando em uma quantidade liberada de indicador de 345 mg.dia -1 . O consumo estimado com o par C33:C32 de n-alcanos nos animais em gaiolas de metabolismo não diferiu do consumo observado (P>0...

Uso de N-alcanos para estimar o consumo e digestibilidade de azevém anual por ovinos; Use of n-alkanes to estimate the intake and digestibility of annual ryegrass by sheep

Reffatti, Mônica Vizzotto
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
Português
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Este trabalho foi conduzido com o objetivo de avaliar a metodologia de n-alcanos na estimativa do consumo e digestibilidade da matéria seca (CMS e DMS) por ovinos consumindo azevém anual (Lolium multiflorum Lam) e verificar o efeito dos ambientes criados através do manejo da pastagem, sob essas variáveis. Os ensaios foram conduzidos nos meses de Agosto e Novembro 2008, e as avaliações feitas nos estádios de pré-florescimento (PF) e florescimento pleno (FP) da pastagem. Para as estimativas foi utilizada a metodologia dos n-alcanos e conduzidos dois experimentos paralelamente, sendo um deles constituído por um ensaio de digestibilidade in vivo e o outro, por um ensaio de pastejo. No estudo com animais confinados também foi estudado o tempo para estabilização da concentração do C32 nas fezes e o efeito do nível de consumo sob essa variável. Nesse ensaio os tratamentos foram ofertas de: 1,5; 2,0; 2,5% do peso vivo (PV) de azevém e à vontade (ad libitum). A concentração de C32 nas fezes estabilizou próximo ao 4º dia de dosagem. O nível de consumo influenciou no tempo para estabilização e na concentração do marcador nas fezes quando estabilizada. A coleta per rectum foi eficiente nas estimativas de consumo e digestibilidade...

Estimativas da digestibilidade e consumo de matéria seca em ovinos alimentados com feno de aveia e concentrado em resposta ao método de administração de alcano externo C32

Fukumoto,Nelson Massaru; Damasceno,Julio Cesar; Roehsig,Lauri; Côrtes,Cristiano; Matsushita,Makoto; Santos,Geraldo Tadeu dos
Fonte: Sociedade Brasileira de Zootecnia Publicador: Sociedade Brasileira de Zootecnia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2006 Português
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Este estudo foi realizado com o objetivo de estimar a digestibilidade da MS, a produção fecal e o consumo de MS em ovinos alimentados com feno de aveia e concentrado. Os tratamentos consistiram de dois métodos de administração do n-alcano externo (C32): equilíbrio; dose pulso. No tratamento equilíbrio, durante oito dias (quatro de adaptação e cinco de coleta), os animais receberam diariamente um pélete de celulose contendo 100 mg de C32. Os animais do tratamento dose pulso receberam um único pélete de celulose contendo 150 mg de C32, sendo realizadas amostragens de fezes diretamente do reto dos animais, durante cinco dias a intervalos de 8 horas. A concentração de n-alcanos internos nos ingredientes da dieta foi baixa, inferior a 50 mg/kg de MS, sendo superior no feno de aveia. Não houve efeito dos tratamentos nas estimativas de digestibilidade da MS, mas houve diferenças entre os n-alcanos internos utilizados, obtendo-se o melhor valor com o alcano C33 (65,01%). As estimativas de produção fecal foram menos variáveis nos animais do tratamento equilíbrio, embora não tenha havido diferenças entre as médias dos tratamentos. O tratamento equilíbrio resultou em melhores estimativas do consumo de MS pelos animais...

Extrahelical cytosine bases in DNA duplexes containing d[GCC]n·d[GCC]n repeats: detection by a mechlorethamine crosslinking reaction

Rojsitthisak, Pornchai; Romero, Rebecca M.; Haworth, Ian S.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Publicado em 15/11/2001 Português
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The cytosine–cytosine (C–C) pair is one of the least stable DNA mismatch pairs. The bases of the C–C mismatch are only weakly hydrogen bonded, and previous work has shown that, in certain sequence contexts, they can become unstacked from the core helix, and adopt an ‘extrahelical’ location. Here, using DNA duplexes with d[GCC]n·d[GCC]n fragments containing C–C mismatches in a 1,4 bp relationship, we show that cytosine bases of different formal mismatch pairs can be crosslinked by mechlorethamine. For example, in the duplex d[CTCTCGCCGCCGCCGTATC]·d[GATACGCCGCCGCCGAGAG], where underlined cytosine bases are present as the formal C–C mismatch pairs C7–C32, C10–C29 and C13–C26, we show that two mechlorethamine crosslinks form between C13 and C29 and between C10 and C32, in addition to crosslinks at C7–C32, C10–C29 and C13–C26 (we have reported previously the crosslinking of formal C–C pairs by mechlorethamine). We interpret the formation of the C13–C29 and C10–C32 crosslinks as evidence of an extrahelical location of the crosslinkable cytosines. Such extrahelical cytosine bases have been observed previously for a single C–C mismatch pair (in the so-called E-motif conformation). In the E-motif, the extrahelical cytosines are folded back towards the 5′-end of the duplex...

Plasmodium falciparum gametocyte adhesion to C32 cells via CD36 is inhibited by antibodies to modified band 3.

Rogers, N J; Targett, G A; Hall, B S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1996 Português
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Plasmodium falciparum gametocyte-infected erythrocytes are characterized by their ability to sequester in the microvasculature of various organs, primarily the spleen and bone marrow. This phenomenon is thought to play a critical role in the development and survival of the sexual stages. Little is known, however, about ligands on the gametocyte-infected erythrocyte. Infection of erythrocytes with mature asexual stages of P. falciparum (trophozoites and schizonts) has been shown to induce modification of the erythrocyte anion transporter, band 3, and this has been linked to the acquisition of an adherent phenotype. Here, we demonstrate for the first time that immature gametocyte-infected erythrocytes also express modified band 3. In vitro binding assays demonstrate that gametocyte-infected erythrocytes of the 3D7 strain utilize this surface receptor for adhesion to C32 amelanotic melanoma cells via the host cell receptor CD36 (platelet glycoprotein IIIb). Adhesion of gametocyte-infected erythrocytes to CD36-transfected CHO cells is also dependent on modified band 3. However, modified band 3 does not mediate adhesion of gametocyte-infected erythrocytes to intercellular adhesion molecule 1, a second host receptor for gametocytes expressed on C32 cells.

Plasmodium falciparum-infected erythrocytes do not adhere well to C32 melanoma cells or CD36 unless rosettes with uninfected erythrocytes are first disrupted.

Handunnetti, S M; Hasler, T H; Howard, R J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1992 Português
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Plasmodium falciparum malaria parasites modify the human erythrocytes in which they grow so that some parasitized erythrocytes (PE) can cytoadhere (C+) to host vascular endothelial cells or adhere in rosettes (R+) to uninfected erythrocytes. These C+ and R+ adherence properties of PE appear to mediate much of the pathogenesis of severe malaria infections, in part by blocking blood flow in microvessels. From one parasite strain, PE were selected in vitro for C+ R+ or C+ R- adherence properties and examined in model adherence assays. The C+ R+ PE cytoadhered poorly to C32 melanoma cells or to immobilized CD36 in a settled-cell assay when uninfected human erythrocytes were present and formed rosettes with PE. C+ R- PE adhered well in the same assays. However, C+ R+ PE adhered very well, even better than C+ R- PE, when the rosettes were disrupted and the C+ R+ PE were purified. Adding back rabbit erythrocytes, which do not form rosettes with C+ R+ PE, had simply a dilutional effect. The ability of rosettes to interfere with the detection of adherence must be dealt with in all future assays of malarial PE adherence. Individual PE were observed attached simultaneously to C32 cells and to a few erythrocytes, suggesting that C+ and R+ adherence properties are coexpressed on the same PE. Coexpression of these adherence properties on the same PE may have pathological importance in vivo...

Assessment of Polymorphism in Zebrafish Mapping Strains

Nechiporuk, Alex; Finney, Janet E.; Keating, Mark T.; Johnson, Stephen L.
Fonte: Cold Spring Harbor Laboratory Press Publicador: Cold Spring Harbor Laboratory Press
Tipo: Artigo de Revista Científica
Publicado em /12/1999 Português
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To assess the level of heterozygosity within two commonly used inbred mapping zebrafish strains, C32 and SJD, we genotyped polymorphic CA-repeat markers randomly dispersed throughout the zebrafish genome. (For clarity purposes we will primarily use the term polymorphic to define polymorphism between strains, and the term heterozygous to address heterogeneity within a strain.) Eight male individuals each from C32 and SJD stocks were typed for 235 and 183 markers, respectively. Over 90% of the markers typed were polymorphic between these two strains. We found a limited number of heterozygous markers persisting in clusters within each inbred line. In the SJD strain, these were mainly limited to a few telomeric regions or regions otherwise distant from centromeres. As expected, centromeric regions were homozygous in the SJD strain, consistent with its derivation from a single half-tetrad individual. In contrast, heterozygous clusters were distributed randomly throughout the genome in the C32 strain, and these clusters could be detected with linked polymorphic markers. Nevertheless, most regions of the C32 strain are homozygous for CA-repeat markers in current stocks. This identification of the heterozygous regions within C32 and SJD lines should permit rapid fixation of these remaining regions in future generations of inbreeding. In addition...

Structure and Biosynthesis of Cuticular Lipids: Hydroxylation of Palmitic Acid and Decarboxylation of C28, C30, and C32 Acids in Vicia faba Flowers 12

Kolattukudy, P. E.; Croteau, Rodney; Brown, Linda
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1974 Português
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The structure and composition of the cutin monomers from the flower petals of Vicia faba were determined by hydrogenolysis (LiAlH4) or deuterolysis (LiAlD4) followed by thin layer chromatography and combined gas-liquid chromatography and mass spectrometry. The major components were 10, 16-dihydroxyhexadecanoic acid (79.8%), 9, 16-dihydroxyhexadecanoic acid (4.2%), 16-hydroxyhexadecanoic acid (4.2%), 18-hydroxyoctadecanoic acid (1.6%), and hexadecanoic acid (2.4%). These results show that flower petal cutin is very similar to leaf cutin of V. faba. Developing petals readily incorporated exogenous [1-14C]palmitic acid into cutin. Direct conversion of the exogeneous acid into 16-hydroxyhexadecanoic acid, 10, 16-dihydroxy-, and 9, 16-dihydroxyhexadecanoic acid was demonstrated by radio gas-liquid chromatography of their chemical degradation products. About 1% of the exogenous [1-14C]palmitic acid was incorporated into C27, C29, and C31n-alkanes, which were identified by combined gas-liquid chromatography and mass spectrometry as the major components of the hydrocarbons of V. faba flowers. The radioactivity distribution among these three alkanes (C27, 15%; C29, 48%; C31, 38%) was similar to the per cent composition of the alkanes (C27, 12%; C29...

A polymer library approach to suicide gene therapy for cancer

Anderson, Daniel G.; Peng, Weidan; Akinc, Akin; Hossain, Naushad; Kohn, Anat; Padera, Robert; Langer, Robert; Sawicki, Janet A.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
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Optimal gene therapy for cancer must (i) deliver DNA to tumor cells with high efficiency, (ii) induce minimal toxicity, and (iii) avoid gene expression in healthy tissues. To this end, we generated a library of >500 degradable, poly(β-amino esters) for potential use as nonviral DNA vectors. Using high-throughput methods, we screened this library in vitro for transfection efficiency and cytotoxicity. We tested the best performing polymer, C32, in mice for toxicity and DNA delivery after intratumor and i.m. injection. C32 delivered DNA intratumorally ≈4-fold better than one of the best commercially available reagents, jetPEI (polyethyleneimine), and 26-fold better than naked DNA. Conversely, the highest transfection levels after i.m. administration were achieved with naked DNA, followed by polyethyleneimine; transfection was rarely observed with C32. Additionally, polyethyleneimine induced significant local toxicity after i.m. injection, whereas C32 demonstrated no toxicity. Finally, we used C32 to deliver a DNA construct encoding the A chain of diphtheria toxin (DT-A) to xenografts derived from LNCaP human prostate cancer cells. This construct regulates toxin expression both at the transcriptional level by the use of a chimeric-modified enhancer/promoter sequence of the human prostate-specific antigen gene and by DNA recombination mediated by Flp recombinase. C32 delivery of the A chain of diphtheria toxin DNA to LNCaP xenografts suppressed tumor growth and even caused 40% of tumors to regress in size. Because C32 transfects tumors locally at high levels...

A Stargardt disease-3 mutation in the mouse Elovl4 gene causes retinal deficiency of C32-C36 acyl phosphatidylcholines

McMahon, Anne; Jackson, Shelley N.; Woods, Amina S.; Kedzierski, Wojciech
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
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Stargardt disease-3 (STGD3) is a juvenile dominant macular degeneration caused by mutations in elongase of very long chain fatty acid-4. All identified mutations produce a truncated protein which lacks a motif for protein retention in endoplasmic reticulum, the site of fatty acid synthesis. In these studies of Stgd3-knockin mice carrying a human pathogenic mutation, we examined two potential pathogenic mechanisms: truncated protein-induced cellular stress and lipid product deficiency. Analysis of mutant retinas detected no cellular stress but demonstrated selective deficiency of C32-C36 acyl phosphatidylcholines. We conclude that this deficit leads to the human STGD3 pathology.

Identifying Plasmodium falciparum cytoadherence-linked asexual protein 3 (CLAG 3) sequences that specifically bind to C32 cells and erythrocytes

Ocampo, Marisol; Rodríguez, Luis E.; Curtidor, Hernando; Puentes, Álvaro; Vera, Ricardo; Valbuena, John J.; López, Ramses; García, Javier E.; Ramírez, Luis E.; Torres, Elizabeth; Cortes, Jimena; Tovar, Diana; López, Yolanda; Patarroyo, Manuel A.; Pa
Fonte: Cold Spring Harbor Laboratory Press Publicador: Cold Spring Harbor Laboratory Press
Tipo: Artigo de Revista Científica
Publicado em /02/2005 Português
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Adhesion of mature asexual stage Plasmodium falciparum parasite-infected erythrocytes (iRBC) to the vascular endothelium is a critical event in the pathology of Plasmodium falciparum malaria. It has been suggested that the clag gene family is essential in cytoadherence to endothelial receptors. Primers used in PCR and RT-PCR assays allowed us to determine that the gene encoding CLAG 3 (GenBank accession no. NP_473155) is transcribed in the Plasmodium falciparum FCB2 strain. Western blot showed that antisera produced against polymerized synthetic peptides from this protein recognized a 142-kDa band in P. falciparum schizont lysate. Seventy-one 20-amino-acid-long nonoverlapping peptides, spanning the CLAG 3 (cytoadherence-linked asexual protein on chromosome 3) sequence were tested in C32 cell and erythrocyte binding assays. Twelve CLAG peptides specifically bound to C32 cells (which mainly express CD36) with high affinity, hereafter referred to as high-affinity binding peptides (HABPs). Five of them also bound to erythrocytes. HABP binding to C32 cells and erythrocytes was independent of peptide charge or peptide structure. Affinity constants were between 100 nM and 800 nM. Cross-linking and SDS-PAGE analysis allowed two erythrocyte binding proteins of around 26 kDa and 59 kDa to be identified...

Interactions between Cytochrome c2 and the Photosynthetic Reaction Center from Rhodobacter sphaeroides : The Cation-pi Interaction†

Paddock, M. L.; Weber, K. H.; Chang, C.; Okamura, M. Y.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 19/07/2005 Português
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The cation-pi interaction between positively charged and aromatic groups is a common feature of many proteins and protein complexes. The structure of the complex between cytochrome c2 (cyt c2) and photosynthetic reaction center (RC) from Rhodobacter sphaeroides exhibits a cation-pi complex formed between Arg-C32 on cyt c2 and Tyr-M295 on the RC (Axelrod et. al (2002) J. Mol. Biol. 319, 501–515). The importance of the cation-pi interaction for binding and electron transfer was studied by mutating Tyr-M295 and Arg-C32. The first and second order rates for electron transfer were not affected by mutating Tyr-M295 to Ala indicating that the cation-pi complex does not greatly affect the association process or structure of the state active in electron transfer. The dissociation constant KD showed a greater increase when Try-M295 was replaced by non-aromatic Ala (3-fold) than by aromatic Phe (1.2-fold) characteristic of a cation-pi interaction. Replacement of Arg-C32 by Ala increased KD (80-fold) largely due to removal of electrostatic interactions with negatively charged residues on the RC. Replacement by Lys, increased KD (6-fold) indicating that Lys does not form a cation-pi complex. This specificity for Arg may be due to a solvation effect. Double mutant analysis indicates interaction energy between Tyr-M295 and Arg-C32 of about −24 meV (−0.6 kcal/mole). This energy is surprisingly small considering the widespread occurrence of cation-pi complexes and may be due to the trade-off between the favorable cation-pi binding energy and the unfavorable desolvation energy needed to bury Arg-C32 in the short-range contact region between the two proteins.

Two Novel Alkane Hydroxylase-Rubredoxin Fusion Genes Isolated from a Dietzia Bacterium and the Functions of Fused Rubredoxin Domains in Long-Chain n-Alkane Degradation▿

Nie, Yong; Liang, Jieliang; Fang, Hui; Tang, Yue-Qin; Wu, Xiao-Lei
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /10/2011 Português
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Two alkane hydroxylase-rubredoxin fusion gene homologs (alkW1 and alkW2) were cloned from a Dietzia strain, designated DQ12-45-1b, which can grow on crude oil and n-alkanes ranging in length from 6 to 40 carbon atoms as sole carbon sources. Both AlkW1 and AlkW2 have an integral-membrane alkane monooxygenase (AlkB) conserved domain and a rubredoxin (Rd) conserved domain which are fused together. Phylogenetic analysis showed that these two AlkB-fused Rd domains formed a novel third cluster with all the Rds from the alkane hydroxylase-rubredoxin fusion gene clusters in Gram-positive bacteria and that this third cluster was distant from the known AlkG1- and AlkG2-type Rds. Expression of the alkW1 gene in DQ12-45-1b was induced when cells were grown on C8 to C32 n-alkanes as sole carbon sources, but expression of the alkW2 gene was not detected. Functional heterologous expression in an alkB deletion mutant of Pseudomonas fluorescens KOB2Δ1 suggested the alkW1 could restore the growth of KOB2Δ1 on C14 and C16 n-alkanes and induce faster growth on C18 to C32 n-alkanes than alkW1ΔRd, the Rd domain deletion mutant gene of alkW1, which also caused faster growth than KOB2Δ1 itself. In addition, the artificial fusion of AlkB from the Gram-negative P. fluorescens CHA0 and the Rds from both Gram-negative P. fluorescens CHA0 and Gram-positive Dietzia sp. DQ12-45-1b significantly increased the degradation of C32 alkane compared to that seen with AlkB itself. In conclusion...

N-Alkanes method to estimate dry matter intake on tropical grasses.

GENRO, T. C. M.; GENRO NETO, J. S.; CÔRREA, A. C. J.; LACA, E. A.
Fonte: In: REUNIÓN DE LA ASOCIACIÓN LATINOAMERICANA DE PRODUCCIÓN ANIMAL, 22., 2011, Montevideo, Uruguay. Memorias... Montevideo: Asociación Uruguaya de Producción Animal, 2011. Publicador: In: REUNIÓN DE LA ASOCIACIÓN LATINOAMERICANA DE PRODUCCIÓN ANIMAL, 22., 2011, Montevideo, Uruguay. Memorias... Montevideo: Asociación Uruguaya de Producción Animal, 2011.
Tipo: Resumo em anais de congresso (ALICE) Formato: 1 CD-ROM.
Português
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This trial was conducted to define which alkane (C31 and C33) must be paired with the external marker (C32) to estimate dry matter intake (DMI) of steers grazing three tropical grasses: Brachiaria brizantha cv. Marandu , Panicum maximum cv. Mombaça e Penisetum purpureum cv. Cameroon. This experiment was carried out at Embrapa Beef Cattle, Campo Grande, MS, Brazil. The steers were rotated on a predetermined schedule of 2 days of grazing per rotational paddock. Rotation order through the paddocks remained constant, with 30 days after each grazing bout. Measurements were made during two grazing periods: the middle of the dry season (August 97), at the beginning of the wet season (November 97). To estimate dry matter intake (DMI) eighteen Nelore steers were dosed during 12 days, twice a day, with alkane C32. From eighth to 12th day faeces were collected twice a day also. Herbage hand-clipping samples for n-alkanes analysis were collected from pastures. The profiles of n-alkanes were determinate from herbage and faeces within the range of C-chain between 27 and 35. We can see a clearly difference between DMI estimated using the pair C32/C33 and C32/C31. C32/C31 underestimated DMI and the pair C32/C33 showed DMI values near to values found in the literature for this steers. Both pairs were able to detect DMI differences between species...

Variabilidade genética e associação entre caracteres agronômicos, fisiológicos e fitoquímicos em variedades de Artemisia annua L

Bolina, Cristiane de Oliveira
Fonte: Pato Branco Publicador: Pato Branco
Tipo: Dissertação de Mestrado
Português
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Artemisia annua L. (Asteraceae) is a highly aromatic annual herb, native from Asia and acclimated in Brazil. The leaves are a rich source of artemisinin, a sesquiterpene lactone used in the preparation of drugs for the treatment of malaria, and also of essential oil used in cosmetics and hygienic products. This study aimed to estimate the genetic variability and correlation between agronomic, physiological and phytochemicals traits in varieties of A. annua, also to characterize the content, yield and essential oil composition. The design was completely randomized and treatments were the varieties Artemis, 2/39x5x3M and 2/39x1V of A. annua, submitted to agronomic, physiological and phytochemical evaluations. For the accomplishment of the genetic distance estimates dissimilarity matrices had been generated using the Euclidean distance and Tocher’s and UPGMA’s grouping methods. Moreover, relative importance of the characters for genetic divergence for the method of Singh was evaluated. The relationship between the studied characters was estimated using Pearson’s correlation coefficient and the significance level was analyzed by test t. The analyses were performed in the Genes software and the dendrograms obtained from the NTSYS program. The separation and quantification of substances present in the essential oil were performed by gas chromatography with flame ionization detector and the identification of them were made in a gas chromatography coupled with mass spectrometer. Tocher’s and UPGMA’s methods agreed among themselves in the formation of groups and the presence of genetic variability within varieties allowed the identification of dissimilar individuals with high average for all traits. The number of branches...

C32, A Young Star Cluster in IC 1613

Wyder, Ted K.; Hodge, Paul W.; Cole, Andrew
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/02/2000 Português
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The Local Group irregular galaxy IC 1613 has remained an enigma for many years because of its apparent lack of star clusters. We report the successful search for clusters among several of the candidate objects identified many years ago on photographic plates. We have used a single HST WFPC2 pointing and a series of images obtained with the WIYN telescope under exceptional seeing conditions, examining a total of 23 of the previously published candidates. All but six of these objects were found to be either asterisms or background galaxies. Five of the six remaining candidates possibly are small, sparse clusters and the sixth, C32, is an obvious cluster. It is a compact, young object, with an age of less than 10 million years and a total absolute magnitude of M_V = -5.78+/-0.16 within a radius of 13 pc.; Comment: 5 pages, 5 figures, to be published in the May 2000 issue of the PASP

Superconductivity in the C32 Intermetallic Compounds AAl(2-x)Si(x), with A=Ca and Sr, and 0.6
Lorenz, B.; Lenzi, J.; Cmaidalka, J.; Meng, R. L.; Sun, Y. Y.; Xue, Y. Y.; Chu, C. W.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 16/08/2002 Português
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The intermetallic compounds AAl2-xSix, where A = Ca, Sr or Ba, crystallize in the C32 structure, same as the recently discovered MgB2 with a high superconducting transition temperature of 39 K. For x = 1, superconductivity has been observed in AAlSi with A = Ca and Sr, but not with A = Ba. The transition temperatures are 7.8 and 5.1 K, respectively for CaAlSi and SrAlSi. The CaAl2-xSix compound system display a Tc-peak at x = 1, a possible x-induced electronic transition at x ~ 0.75 and a possible miscibility gap near x ~ 1.1 which results in a very broad superconducting transition. The Seebeck coefficients of AAlSi indicate that their carriers are predominantly electrons in nature, in contrast to the holes in MgB2.; Comment: 10 pages, 6 figures

N-alcanos para estimar o consumo voluntário de forragem em bovinos usando cápsulas de liberação controlada; N-alkanes to estimate voluntary forage intake of cattle using controlled-release capsules

Oliveira, Dimas Estrasulas de; Manella, Marcelo de Queiroz; Tedeschi, Luis Orlindo; Silva, Sila Carneiro da; Lanna, Dante Pazzanese Duarte
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/01/2008 Português
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N-alkanes have been used as internal markers in digestibility trials with ruminants and non-ruminants for more than 20 years. In this study, two trials were conducted under different feeding regimes to (i) evaluate the release rate of n-alkanes of controlled-release capsules in the rumen of rumen-cannulated steers either grazing or restrained in metabolic stalls and (ii) estimate voluntary forage intake of the same steers in metabolic stalls. Six rumen-cannulated Nelore steers were allocated to individual metabolic stalls and were fed diets with varying forage to concentrate ratios (80:20, 60:40, and 40:60; respectively). Corn silage was the only forage source. In the grazing trial, the same steers were evaluated under three feeding managements (Brachiaria brizantha cv. Marandu unsupplemented or supplemented with either 0.3% or 0.6% of live weight of a concentrate). The release rate of the n-alkanes (mg d-1) was measured by multiplying the distance (mm d-1) the capsule plunger travelled after 3, 7, 10, 13, and 17 d of rumen infusion to the n-alkanes concentration of capsule tablets (mg mm-1). There was an effect of day of measurement (P < 0.05) on the release rate of animals restrained in metabolic stalls and grazing. However, no effect (P >; 0.05) of feeding management or feeding management x day of measurement interaction was observed. Values averaged 6.9 and 14.8%...

Estimativa da ingestão e digestibilidade de erva e bolota em porcos alentejanos pela técnica dos n-alcanos

Mendes,C.; Ferraz-de-Oliveira,M. I.; Ribeiro,T.; d’Abreu,M. C.
Fonte: Sociedade de Ciências Agrárias de Portugal Publicador: Sociedade de Ciências Agrárias de Portugal
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 Português
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Com o objectivo de estimar, em porcos Alentejanos, a ingestão e a digestibilidade de erva e bolota, foi realizado um ensaio utilizando n-alcanos de cadeia longa como marcadores fecais. Oito animais, alojados em caixas metabólicas, distribuídos aleatoriamente em 2 grupos de 4 animais cada, foram sujeitos a dois tratamentos. Cada animal do grupo 1 recebeu um bolinho por dia, contendo 100 mg de C32 e 150 mg de C36 e do grupo 2, dois bolinhos por dia contendo 50 mg de C32 e 75 mg de C36. Os animais foram alimentados com erva e bolota ao longo de todo o ensaio. A ingestão e a digestibilidade da dieta foram determinadas individualmente, através da medição das quantidades de alimento ingeridas e de fezes produzidas durante 5 dias e estimadas através da utilização da técnica dos n-alcanos. As estimativas da digestibilidade feitas através da utilização dos n-alcanos naturais C25 e C27 permitiram a obtenção de resultados muito próximos das medições in vivo. Os C29 e C31, em combinação com os nalcanos artificiais (C32 e C36), forneceram as estimativas da digestibilidade mais próximas da determinada, sendo os pares C29:C32 e C29:C36 os que forneceram as melhores estimativas para a ingestão. A administração dos C32 e C36 uma ou duas vezes por dia não demonstrou ter qualquer influência nas estimativas realizadas. A composição da dieta (bolota e erva)...