1,348 research outputs found

    Estrutura de tamanho e fertilidade em uma população de Eriocnema fulva Naudin (Melastomataceae) no sudeste do Brasil

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    Eriocnema fulva Naudin is an endangered perennial herbaceous plant, endemic to Minas Gerais state, Brazil. This study was conducted in the Jambreiro Forest (19° 58' -59'S and 43° 52' -55' W, 800-1100 m altitude). In an attempt to describe the population size structure and its association with individual fertility, fifteen 1 x 1 m contiguous plots were set. We tagged, counted, and measured a total of 260 individuals in 1997, 1998 and 1999. Young individuals with leaf lamina lengths 10 cm in length did not reproduce was 2.69%. The highest survival probability of the large-sized individuals confirmed the strong correlation between size and survival. The data indicated that size is important for the fertility of E. fulva, and it may be one of the relevant aspects to be considered for analyses of survival probability. The intraspecific competition, which was indicated by negative correlation between fruit production per size unit and density, can affect fertility, as larger plants had higher fruit production.Eriocnema fulva é endêmica no estado de Minas Gerais e é ameaçada de extinção. Este estudo foi realizado na Mata do Jambreiro (19° 58' -59' S e 43° 52'-55' W, 800-1100 m de altitude) Com o objetivo de descrever a estrutura de tamanho da população e suas relações com a fertilidade dos indivíduos, foram instaladas 15 parcelas contíguas de 1 x 1m. Marcamos, contamos e medimos um total de 260 indivíduos em 1997, 1998 e 1999. Os indivíduos jovens com o comprimento do limbo 10 cm não se reproduzirem foi de 2,69%. A maior probabilidade de sobrevivência dos indivíduos de maior tamanho confirmou a forte correlação entre tamanho e sobrevivência. Os dados mostraram que o tamanho é importante para a fertilidade de Eriocnema fulva e pode ser relevante para análises de probabilidade de sobrevivência da espécie. A competição intra-específica, indicada pela correlação negativa entre a produção de frutos por unidade de tamanho e a densidade, pode influir na fertilidade, pois plantas maiores apresentaram maior produção de frutos.685693Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Boko Haram Assault on Nigeria: Towards Effective Mass Media Response

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    The Islamic sect, Boko Haram has waged a relentless war of attrition on Nigeria since 2009. The sect has attacked mostly government’s establishments, security operatives, places of worships, markets and lately, the mass media. These assaults have accounted for countless deaths and injuries to Nigerians and destruction of property worth millions. Many have expressed concern that the attacks if not decisively checked could spell grave danger to stability of the country, worsen security of lives and properties as well as freedom of speech and other related freedoms. The mass media, given their power and influence could play very significant role in winning the war against the Boko Haram insurgency. This paper critically examines the whole situation: the Boko Haram sect and its attacks; the assault on media houses, government’s response, mass media and objectivity, the media and terrorism and makes recommendations on how the mass media could be effectively deployed in the effort to stop the sect

    SHRUB AND TREE SPECIES COMPOSITION IN THE CERRADOS OF SOUTHWEST MINAS GERAIS

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    In order to improve the knowledge about variations in the floristic community of Brazilian cerrado, especially in regard to soil and climate conditions, we conducted a floristic assessment of the tree and shrub community of three disjoint adjacent regions situated in three municipalities of southwest Minas Gerais state (geographical coordinates 20-23 degrees S and 44-47 degrees W). Over a period of 24 months, in 49 allocated plots of 20 x 20 m, all tree and shrub species 1 m high or more in vegetative and/or reproductive stage were sampled. Additional random samples of blossoming plants were collected outside plots, and each plot was analyzed and categorized for soil type. 170 botanical species were identified belonging to 103 genera and 46 families. Family Fabaceae and genus Miconia presented the largest number of species. Although the cerrado of southwest Minas Gerais extends over marginal areas of occurrence of Brazilian cerrado, its floristic composition is rich not only in species but also in genera and families. Some species found in these cerrados also occur in local semideciduous forests, while other species that are frequently found in other areas of cerrado were not found in southwest Minas Gerais. Tibouchina sellowiana does not feature in the list of species occurring in Brazilian cerrados. There is little similarity among the three sampled areas due to soil factors and different types of human influence in each of the areas. Alpinopolis presented cerrado sensu stricto - subtype cerrado ralo, with 75 species and red-yellow latosol. Campo do Meio presented cerrado sensu stricto - subtype cerrado tipico, with 88 species and red latosol. Pimenta falls under the cerraddo category, with 124 species and red latosol. On the subsurface, the soil of Pimenta was found to present lower Al(+++)saturation, which apparently shapes conditions for a more vigorous vegetation. The cerrado soils sampled in this study showed high similarity to cerrado soils in other parts of Brazil.15214215

    Protein aggregation containing beta-amyloid, alpha-synuclein and hyperphosphorylated tau in cultured cells of hippocampus, substantia nigra and locus coeruleus after rotenone exposure

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    <p>Abstract</p> <p>Background</p> <p>Protein aggregates containing alpha-synuclein, beta-amyloid and hyperphosphorylated tau are commonly found during neurodegenerative processes which is often accompanied by the impairment of mitochondrial complex I respiratory chain and dysfunction of cellular systems of protein degradation. In view of this, we aimed to develop an <it>in vitro </it>model to study protein aggregation associated to neurodegenerative diseases using cultured cells from hippocampus, locus coeruleus and substantia nigra of newborn Lewis rats exposed to 0.5, 1, 10 and 25 nM of rotenone, which is an agricultural pesticide, for 48 hours.</p> <p>Results</p> <p>We demonstrated that the proportion of cells in culture is approximately the same as found in the brain nuclei they were extracted from. Rotenone at 0.5 nM was able to induce alpha-synuclein and beta amyloid aggregation, as well as increased hyperphosphorylation of tau, although high concentrations of this pesticide (over 1 nM) lead cells to death before protein aggregation. We also demonstrated that the 14kDa isoform of alpha-synuclein is not present in newborn Lewis rats.</p> <p>Conclusion</p> <p>Rotenone exposure may lead to constitutive protein aggregation <it>in vitro</it>, which may be of relevance to study the mechanisms involved in idiopathic neurodegeneration.</p

    Crescimento foliar de Eriocnema fulva Naudin (Melastomataceae) em um fragmento florestal no Brasil sudeste

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    Eriocnema fulva Naudin is an endangered herbaceous, perennial, iteroparous, evergreen species geographically restricted to southeastern-center Minas Gerais State, SE Brazil. The individuals occur as patches on rocky riverbanks shaded by seasonal semideciduous Atlantic forest; they are fixed by roots and have a pending stem. Aiming to investigate leaf development and its importance for individual survival, fifteen contiguous plots (1 x 1 m) were set down in Jambreiro Forest (19° 58?-59? S and 43° 52?-55? W, 800-1100 m altitude), in the municipality of Nova Lima. A total of 260 individuals with the largest leaf blade length > 1 cm was tagged and measured in 1997, 1998, and 1999. Leaf expansion was recorded each month during 26 months until April 2000. Plant size was measured through leaf blade length, petiole length, stem length, and number of leaves. Significant changes were detected only after two years, thus indicating that plant growth is slow. The proportion of surviving leaves after two years was 60%. Total blade expansion took over 14 months, a slow growth rate when compared to leaves of other tropical forest canopy and understory species. Long leaf lifespans are to be found in plants exhibiting slow growth, and we observed that some leaves lived longer than three years. Petiole growth can help to better position the leaf in the search for light, thus contributing to the growth and survival of the plant. The relationships among size measures were significant, reinforcing the great contribution of leaf size for plant size. The age of the largest individual was estimated as 36 years based on the median annual leaf production rate.Eriocnema fulva é uma espécie herbácea, perene, iteropárica, com distribuição geográfica restrita ao centro-sudeste do Estado de Minas Gerais, Brasil, e ameaçada de extinção. Os indivíduos ocorrem agrupados em paredões rochosos, na beira de riachos sombreados pela Mata Atlântica estacional semidecídua e têm caule que pendem do barranco. Com o objetivo de investigar o desenvolvimento da folha e sua importância para a sobrevivência dos indivíduos, foram instaladas 15 parcelas contíguas de 1 x 1 m na Mata do Jambreiro (19° 58?-59?S, 43° 52?-55? W, 800-1100 m de altitude), município de Nova Lima. Todos os indivíduos cuja maior folha tivesse comprimento do limbo maior ou igual a 1 cm foram marcados, sendo medidos em 1997, 1998 e 1999. O tempo de expansão da folha foi registrado mensalmente durante 26 meses até abril de 2000. Na área amostrada foram marcados 260 indivíduos cujo limbo foliar tinha comprimento > 1cm. O tamanho das plantas, medido através do comprimento do limbo e do pecíolo e do número de folhas, apresentou mudanças significativas somente após dois anos, indicando que o crescimento é lento. A proporção das folhas sobreviventes após dois anos foi de 60%. O tempo necessário para a expansão da folha foi superior a 14 meses e é lento quando comparado com o de outras espécies do dossel ou do sub-bosque da floresta tropical. Maior longevidade foliar tende a ser encontrada em plantas de crescimento lento. Observamos que algumas folhas tiveram maior longevidade que 3 anos. O crescimento do pecíolo pode ajudar no melhor posicionamento da folha na busca de luz no sub-bosque, contribuindo para o crescimento e sobrevivência da planta. As relações entre a folha e demais medidas de tamanho foram significativas, indicando sua grande importância para o tamanho de cada planta. A idade do indivíduo de maior tamanho foi estimada em 36 anos através da taxa mediana de produção anual de folhas.110Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Análise in silico de proteínas quinases expressas em Coffea arabica.

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    Apesar da indiscutível importância agronômica do café, particularmente para o Brasil, esta cultura ainda é alvo de diferentes estresses que causam perda em sua produtividade. A resposta do cafeeiro aos diferentes sinais como patógenos e de condições ambientais adversas é ainda desconhecida. Com o objetivo de identificar proteínas quinases, o banco de seqüências expressas de Café (CAFEST) foi investigado. A análise do banco de dados CafEST revelou 479 seqüências identificadas como quinases que formaram um conjunto de 153 unigenes. As proteínas codificadas pelos segmentos expressos correspondem a diferentes e importantes categorias de quinases (MAPK, MAPKK, MAPKKK, receptores, etc). A análise filogenética mostrou a conservação das proteínas expressas no cafeeiro comparado a outras plantas e fungos. Os presentes resultados indicam que a resposta a estresses seja conservada em cafeeiro, provavelmente mediada pelos mecanismos de fosforilação em cascata. Além disso, apontam para o aprofundamento dos estudos destas vias como contribuição aos fenômenos relacionados à interação planta-patógeno

    Utility of Prophylactic Percutaneous Gastrostomy in Patients With Head and Neck Cancer Receiving Concurrent Chemoradiotherapy: A Multicenter Analysis

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    Introduction: Patients with head and neck cancer (HNC) have an elevated incidence of cachexia and malnutrition due to the tumor's location interfering with oral feeding. Concurrent chemoradiation (CCRT) can have an emetic effect and cause dysphagia and oral mucositis. Adequate nutrition improves immunity, raises the response to therapy, reduces adverse effects, and improves survival. Numerous studies have suggested the utility of nutritional support from percutaneous endoscopic gastrostomy (PEG) in HNC patients. Although PEG is usually considered a safe procedure, it has a mortality rate of 0-2.2% and a risk of other procedure-related complications of 17-40%. Our work intends to evaluate the utility of PEG in patients with locally advanced HNC who underwent CCRT. Methods: We performed a cohort study at three institutions. We included patients with HNC who underwent definitive CCRT treatment from January 2013 to December 2022. The study consisted of an observational, descriptive, retrospective analysis of prespecified clinical data. Descriptive statistics were used to compare the data between the PEG group and the non-PEG group. Analysis of covariance (ANCOVA) was used for covariance analysis. Fisher's exact test was used to compare proportional data and Student's t-test was used to assess the differences in continuous data. Survival analysis was performed using the Kaplan-Meier estimator. P-values of <0.05 were considered to be indicative of statistical significance. The SPSS Statistics version 28.0 (Armonk, NY: IBM Corp.) was used to perform all statistical evaluations. Results: We identified 90 eligible patients diagnosed with local advanced HNC who had received definitive CCRT with three weekly cycles of cisplatin as follows: 44 with a prophylactic PEG tube and 46 without a prophylactic PEG tube. Most patients were male (84.4%) and 50% of patients were diagnosed with stage IVa HNC at the time of diagnosis. There wasn't an effect of PEG placement on BMI at the end of CCRT after controlling for the effect of baseline BMI (F {1.84}=0.065 {p=0.799}). In the study population, BMI was significantly lower after CCRT (21.30 kg/m2 vs. 23.97 kg/m2), t (86)=12.389, p<0.001. In the subgroup with baseline BMI <18.5 kg/m2 (15 patients), 90% of patients with prophylactic PEG were able to complete the three planned cycles of chemotherapy vs. 66.7% in the non-PEG group. Ten patients in the PEG group (22.7%) referred feeding tube dependency. Patients with dysphagia were 3.2 times more likely to have placed prophylactic PEG (p=0.007). The difference in overall survival and progression-free survival between the two groups was not statistically significant (p=0.57 and p=0.497, respectively). Conclusion: In this study using real-world data, we found a potentially protective effect of PEG in underweight patients with locally advanced HNC performing CCRT in order to complete three cycles of treatment.info:eu-repo/semantics/publishedVersio

    Role of GP82 in the Selective Binding to Gastric Mucin during Oral Infection with Trypanosoma cruzi

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    Oral infection by Trypanosoma cruzi has been the primary cause of recent outbreaks of acute Chagas' diseases. This route of infection may involve selective binding of the metacyclic trypomastigote surface molecule gp82 to gastric mucin as a first step towards invasion of the gastric mucosal epithelium and subsequent systemic infection. Here we addressed that question by performing in vitro and in vivo experiments. A recombinant protein containing the complete gp82 sequence (J18), a construct lacking the gp82 central domain (J18*), and 20-mer synthetic peptides based on the gp82 central domain, were used for gastric mucin binding and HeLa cell invasion assays, or for in vivo experiments. Metacyclic trypomastigotes and J18 bound to gastric mucin whereas J18* failed to bind. Parasite or J18 binding to submaxillary mucin was negligible. HeLa cell invasion by metacyclic forms was not affected by gastric mucin but was inhibited in the presence of submaxillary mucin. Of peptides tested for inhibition of J18 binding to gastric mucin, the inhibitory peptide p7 markedly reduced parasite invasion of HeLa cells in the presence of gastric mucin. Peptide p7*, with the same composition as p7 but with a scrambled sequence, had no effect. Mice fed with peptide p7 before oral infection with metacyclic forms developed lower parasitemias than mice fed with peptide p7*. Our results indicate that selective binding of gp82 to gastric mucin may direct T. cruzi metacyclic trypomastigotes to stomach mucosal epithelium in oral infection
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