981 resultados para sp-equared sp2 sp^2 hybrid orbital


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The effects of culture filtrates of Fusarium oxysporum and Sclerotium rolfsii on egg hatching and juvenile survival of Meloidogyne incognita in vitro and impact of these filtrates on infectivity of M. incognita were investigated on soybean seedlings. Five- and 10-day-old filtrates of F. oxysporum caused 65 and 54% egg-hatching inhibition, while that of S. rolfsii caused 61 and 49% inhibition, respectively. Juveniles of M. incognita died within 6 days when incubated in 5-day-old filtrate of F. oxysporum, while the similar filtrate of S. rolfsii caused 100% juvenile mortality on the fifth day. Filtrates reduced root galling, egg population, number of adult females in soybean plants at harvest and also soil population. Culture filtrates could be used as source of biological nematicides.

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Two bacterial strains, 2AC and 4BC, both capable of utilizing naphthalene-2-sulfonic acid (2-NSA) as a sole source of carbon, were isolated from activated sludges previously exposed to tannery wastewater. Enrichments were carried out in mineral salt medium (MSM) with 2-NSA as the sole carbon source. 16S rDNA sequencing analysis indicated that 2AC is an Arthrobacter sp. and 4BC is a Comamonas sp. Within 33 h, both isolates degraded 100% of 2-NSA in MSM and also 2-NSA in non-sterile tannery wastewater. The yield coefficient was 0.33 g biomass dry weight per gram of 2-NSA. A conceptual model, which describes the aerobic transformation of organic matter, was used for interpreting the biodegradation kinetics of 2-NSA. The half-lives for 2-NSA, at initial concentrations of 100 and 500 mg/l in MSM, ranged from 20 h (2AC) to 26 h (4BC) with lag-phases of 8 h (2AC) and 12 h (4BC). The carbon balance indicates that 75-90% of the initial TOC (total organic carbon) was mineralized, 5-20% remained as DOC (dissolved organic carbon) and 3-10% was biomass carbon. The principal metabolite of 2-NSA biodegradation (in both MSM and tannery wastewater) produced by Comamonas sp. 4BC had a MW of 174 and accounted for the residual DOC (7.0-19.0% of the initial TOC and 66% of the remaining TOC). Three to ten percent of the initial TOC (33% of the remaining TOC) was associated with biomass. The metabolite was not detected when Arthrobacter sp. 2AC was used, and a lower residual DOC and biomass carbon were recorded. This suggests that the two strains may use different catabolic pathways for 2-NSA degradation. The rapid biodegradation of 2-NSA (100 mg/l) added to non-sterile tannery wastewater (total 2-NSA, 105 mg/l) when inoculated with either Arthrobacter 2AC or Comamonas 4BC showed that both strains were able to compete with the indigenous microorganisms and degrade 2-NSA even in the presence of alternate carbon sources (DOC in tannery wastewater = 91 mg/l). The results provide information useful for the rational design of bioreactors for tannery wastewater treatment.

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Pahayokolides A-D are cytotoxic cyclic polypeptides produced by the freshwater cyanobacterium Lyngbya sp. strain 15-2 that possess an unusual β-amino acid, 3-amino-2,5,7,8-tetrahydroxy-10-methylundecanoic acid (Athmu). The absolute configuration of pahayokolides A-D was determined using advanced Marfey’s method. It was also confirmed that a pendant N-acetyl- N-methyl leucine moiety in pahayokolide A was absent in pahayokolides B and pahayokolides C-D were conformers of pahayokolide A. Feeding experiments indicated that the biosynthesis of the Athmu sidechain arises from leucine or α-ketoisovalerate, however could not be further extended by three rounds of condensation with malonate units. Putative four peptide and one unique polyketide synthetases in Lyngbya sp. strain 15-2 were identified by using a PCR method and degenerate primers derived from conserved core sequences of known NRPSs and PKSs. Identification of one unique KS domain conflicted with the logic rule that the long side chain of Athmu was assembled by three rounds of ketide extensions if PKSs were involved. A gene cluster (pah) encoding a peptide synthetase putatively producing pahayokolide was cloned, partially sequenced and characterized. Seven modules of the non-ribosomal peptide synthetase (NRPS) were identified. Ten additional opening reading frames (ORFs) were found, responsible for peptide resistance, transport and degradation. Although the predicted substrate specificities of NRPS agreed with the structure of pahayokolide A partially, the disagreement could be explained. However, no PKS gene was found in the pah gene cluster.

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Pahayokolides A-D are cytotoxic cyclic polypeptides produced by the freshwater cyanobacterium Lyngbya sp. strain 15-2 that possess an unusual β-amino acid, 3-amino-2,5,7,8-tetrahydroxy-10-methylundecanoic acid (Athmu). The absolute configuration of pahayokolides A-D was determined using advanced Marfey’s method. It was also confirmed that a pendant N-acetyl-N-methyl leucine moiety in pahayokolide A was absent in pahayokolides B and pahayokolides C-D were conformers of pahayokolide A. Feeding experiments indicated that the biosynthesis of the Athmu sidechain arises from leucine or α-ketoisovalerate, however could not be further extended by three rounds of condensation with malonate units. Putative four peptide and one unique polyketide synthetases in Lyngbya sp. strain 15-2 were identified by using a PCR method and degenerate primers derived from conserved core sequences of known NRPSs and PKSs. Identification of one unique KS domain conflicted with the logic rule that the long side chain of Athmu was assembled by three rounds of ketide extensions if PKSs were involved. A gene cluster (pah) encoding a peptide synthetase putatively producing pahayokolide was cloned, partially sequenced and characterized. Seven modules of the non-ribosomal peptide synthetase (NRPS) were identified. Ten additional opening reading frames (ORFs) were found, responsible for peptide resistance, transport and degradation. Although the predicted substrate specificities of NRPS agreed with the structure of pahayokolide A partially, the disagreement could be explained. However, no PKS gene was found in the pah gene cluster.

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The title compound, C(16)H(18)O(2)P(2), possesses two stereogenic P atoms and shows a distorted s-cis conformation of each O=P-C=C moiety. This has been suggested on the basis of the stereochemical result of 1,3-dipolar cyclo-additions with nitro-nes and is now confirmed by the present crystal structure analysis. There are two crystallographically independent molecules in the asymmetric unit.

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Multi-element analyses of sediment samples from the Santos-Cubatão Estuarine System were carried out to investigate the spatial and seasonal variability of trace-element concentrations. The study area contains a rich mangrove ecosystem that is a habitat for tens of thousands of resident and migratory birds, some of them endangered globally. Enrichments of metals in fine-grained surface sediments are, in decreasing order, Hg, Mn, La, Ca, Sr, Cd, Zn, Pb, Ba, Cu, Cr, Fe, Nb, Y, Ni and Ga, relative to pre-industrial background levels. The maximum enrichment ranged from 49 (Hg) to 3.1 (Ga). Mercury concentrations were greater in the Cubatão river than in other sites, while the other elements showed greater concentrations in the Morrão river. Concentrations of Mn were significantly greater in winter and autumn than in summer and spring. However, other elements (e.g. Cd and Pb) showed the opposite, with greater concentrations in summer and spring. This study suggests that seasonal changes in physical and chemical conditions may affect the degree of sediment enrichment and therefore make the assessment of contamination difficult. Consequently, these processes need to be considered when assessing water quality and the potential contamination of biota.

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This paper presents the behavior of three bored piles conducted in diabasic soil submitted to uplift forces. The piles were built at the site for Experimental Studies in Soil Mechanics and Foundations of UNICAMP, located in the city of Campinas, Brazil. Field tests have already been conducted at the site (SPT, CPT, DMT and PMT), as well as laboratory tests by using sample soils taken from a well up to 17 m deep. The water table is not checked until a depth of 17 m. In order to check the behavior of the piles when submitted to uplift forces, slow static load tests were carried out as the recommendations of NBR 12131. The carrying capacity of these piles was also provided by means of theoretical methods, appropriate for uplift forces, and through semi-empirical methods appropriate for compression forces, considering only the portion of lateral resistance. The values estimated by using the considered methods were compared to those obtained by means of load tests. One of the tested piles was extracted from the soil to be the subject of a study on its geometry.

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Lianas are characteristic, abundant and ecologically important members of tropical forest but they have been neglected in floristics and phytossociological studies. This work presents a floristic survey of the lianas species at Estação Ecológica do Noroeste Paulista (EENP), and a comparison of the list of species recorded in this work with those reported for other fragments of São Paulo state. The EENP (20º48'36'' S and 49º22'50'' W) is at 468 m of altitude and comprises an area of 168,43 ha, divided into three fragments of vegetation. Samples of lianas were collected in the interior and along the edges of the forest fragments. It was identified 105 species: 99 Magnoliopsida (60 genera and 22 families); six Liliopsida (three genera and three families). The richest families in species comprised 59% of the total of lianas sampled. The dendrogram of similarity showed a low similarity between the forest situated in the littoral (Atlantic Forest) and those located in the interior of the state of São Paulo. Some other authors, also analysing the similarity of forest of the interior and Atlantic Forest of São Paulo state, but considering only the trees reported similar result.

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We estimate litter production and leaf decomposition rate in a cerradão area, physiognomy little studied and very threatened in São Paulo State. During the period of study, litter production was 5646.9 kg.ha-1.year-1, which the 'leaf' fraction corresponded to 4081.2 kg.ha¹.year¹; the 'branch' fraction, to 1066.1 kg.ha-1.year-1; the 'reproductive structures' fraction, to 434.1 kg.ha-1.year-1; and the 'miscellaneous' fraction to 65.5 kg.ha-1.year-1. Litter production was highly seasonal and negatively correlated with relative humidity and air temperature. Leaf production was negatively correlated with relative humidity, rainfall, and air temperature. There was no significant difference between litter production found in this study and those in two other sites with cerradão and semideciduous forest, but these physiognomies differed significantly from the cerrado sensu stricto. Leaf decomposition rate (K) was 0.56. Half-life of the decomposing material was 1.8 years and turnover time was 2.3 years.

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A new species of dactylogyrid monogenean, Apedunculata discoidea gen. n., sp. n. is described and illustrated from the gills of the freshwater fish Prochilodus lineatus (Valenciennes, 1837) in pisciculture ponds from Pirassununga, São Paulo, Brazil. Diagnostic characters of the new genus and species are: 1) vagina dextrolateral slightly sclerotised, opening anteriorly at level of copulatory complex; 2) copulatory organ coiled with two counterclockwise rings; 3) Accessory piece distal and not articulated; 4) body disk-shaped, lacking a peduncle.

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PURPOSE: To collect information and opinions from a group of diabetic patients regarding diabetic retinopathy and its treatment, in order to get reliable information that can help to improve programs and actions to control and prevent this ocular disease. METHODS: A cross-sectional study was performed. The sample was from 980 diabetic patients seen in a diabetic association. A previous questionnaire was made with general questions about the main subject. Thereafter, an appropriate questionnaire was prepared. RESULTS: The sample showed that among 299 patients with age ranging from 16 to 83 years, with a mean of 57 years, mainly female (67.91%) did not know how severe their disease was (30.8%), or believed that it was not a serious problem (19.7%). The laser technique to solve diabetic retinopathy was known by 60.2% of the patients. It was reported as the only treatment available by 24.1%. Among the reasons for no treatment 59.8% reported that they did not think it was necessary and 29.7% could not afford it. CONCLUSIONS: Patients showed lack of knowledge about how serious is diabetic retinopathy, the possibility of using laser technique for it and the severity of the disease. Some patients believed in the efficacy of the treatment and some patients did not, but all of them reported that they were afraid of submitting to it.

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física