bluuebunny/crossref_metadata_2025 huggingface dataset:
Secondary metabolites from marine microorganisms
Authors: KELECOM ALPHONSE
Published: April 2005

After 40 years of intensive research, chemistry of marine natural products has become a mature field. Since 1995, there are signals of decreased interest in the search of new metabolites from traditional sources such as macroalgae and octocorals, and the number of annual reports on marine sponges stabilized. On the contrary, metabolites from microorganisms is a rapidly growing field, due, at least in part, to the suspicion that a number of metabolites obtained from algae and invertebrates may be produced by associated microorganisms. Studies are concerned with bacteria and fungi, isolated from seawater, sediments, algae, fish and mainly from marine invertebrates such as sponges, mollusks, tunicates, coelenterates and crustaceans. Although it is still to early to define tendencies, it may be stated that the metabolites from microorganisms are in most cases quite different from those produced by the invertebrate hosts. Nitrogenated metabolites predominate over acetate derivatives, and terpenes are uncommon. Among the latter, sesquiterpenes, diterpenes and carotenes have been isolated; among nitrogenated metabolites, amides, cyclic peptides and indole alkaloids predominate.
A multidisciplinary approach to the study of the fluminense vegetation
Authors: KELECOM ALPHONSE , REIS GEISA L. , FEVEREIRO PAULO C.A. , SILVA JANIE G. , SANTOS MARCELO G. , MELLO NETO CÍCERO B. , GONZALEZ MARCELO S. , GOUVEA RITA C.S. , ALMEIDA GILBERTO S.S.
Published: April 2005

The fluminense vegetation, more specifically the flora from the Jurubatiba restinga has been investigated by a multidisciplinary team of botanists, chemist, radiobiologist, insect physiologists and geneticist. Vouchers of 564 specimens have been collected, identified, organized in an herbarium, and a database is being build up containing, in addition to classical botanical data, chemical data and information on the potential economic use either for landscape gardening, alternative foods or as medicinal plants. Phytochemical studies of the Guttiferae, Clusia hilariana, yielded oleanolic acid and nemorosone. Their biological activities against the haematophagous insect Rhodnius prolixus vector of Chagas disease have been investigated. Finally, it has been observed that aquatic plants possessed high levels of the natural radionuclide polonium-210, which seems to be originated mainly from soil rather than from atmospheric supply.
A note on tensor fields in Hilbert spaces
Authors: BILIOTTI LEONARDO , MERCURI FRANCESCO , TAUSK DANIEL V.
Published: April 2005

We discuss and extend to infinite dimensional Hilbert spaces a well-known tensoriality criterion for linear endomorphisms of the space of smooth vector fields in n.
New enamine derivatives of lapachol and biological activity
Authors: OLIVEIRA MAILCAR F. , LEMOS TELMA L.G. , MATTOS MARCOS C. DE , SEGUNDO TACIANA A. , SANTIAGO GILVANDETE M.P. , BRAZ-FILHO RAIMUNDO
Published: April 2005

A convenient synthesis of the new enamine derivatives 2-(4-morpholinyl)-3-(3-methyl-2-butenyl)-1,4-naphthalenedione, 2-(1-piperidinyl)-3-(3-methyl-2-butenyl)-1,4-naphtalenedione and 2-(1-pyrrolidinyl)-3-(3-methyl-2-butenyl)-1,4-naphthalenedione was carried out from natural 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthalenedione (lapachol) and morpholine, piperidine and pyrrolidine. The structures of the products were established mainly by NMR analysis, including 2D experiments. Biological activities of these products were evaluated against Artemia salina, Aedes aegypti and cytotoxicity using A549 human breast cells.
40Ar/39Ar geochronology at the Instituto de Geociências, USP: instrumentation, analytical procedures, and calibration
Authors: VASCONCELOS PAULO M. , ONOE ARTUR T. , KAWASHITA KOJI , SOARES ADALBERTO J. , TEIXEIRA WILSON
Published: April 2005

Laser heating 40Ar/39Ar geochronology provides high analytical precision and accuracy, mum-scale spatial resolution, and statistically significant data sets for the study of geological and planetary processes. A newly commissioned 40Ar/39Ar laboratory at CPGeo/USP, São Paulo, Brazil, equips the Brazilian scientific community with a new powerful tool applicable to the study of geological and cosmochemical processes. Detailed information about laboratory layout, environmental conditions, and instrumentation provides the necessary parameters for the evaluation of the CPGeo/USP 40Ar/39Ar suitability to a diverse range of applications. Details about analytical procedures, including mineral separation, irradiation at the IPEN/CNEN reactor at USP, and mass spectrometric analysis enable potential researchers to design the necessary sampling and sample preparation program suitable to the objectives of their study. Finally, the results of calibration tests using Ca and K salts and glasses, international mineral standards, and in-house mineral standards show that the accuracy and precision obtained at the 40Ar/39Ar laboratory at CPGeo/USP are comparable to results obtained in the most respected laboratories internationally. The extensive calibration and standardization procedures undertaken ensure that the results of analytical studies carried out in our laboratories will gain immediate international credibility, enabling Brazilian students and scientists to conduct forefront research in earth and planetary sciences.
Geological features and the Paleoproterozoic collision of four Archean crustal segments of the São Francisco Craton, Bahia, Brazil: a synthesis
Authors: BARBOSA JOHILDO S.F. , SABATÉ PIERRE
Published: April 2005

Recent geological, geochronological and isotopic research has identified four important Archean crustal segments in the basement of the São Francisco Craton in the State of Bahia. The oldest Gavião Block occurs in the WSW part, composed essentially of granitic, granodioritic and migmatitic rocks. It includes remnants of TTG suites, considered to represent the oldest rocks in the South American continent (~ 3,4Ga) and associated Archean greenstone belt sequences. The youngest segment, termed the Itabuna-Salvador-Curaçá Belt is exposed along the Atlantic Coast, from the SE part of Bahia up to Salvador and then along a NE trend. It is mainly composed of tonalite/trondhjemites, but also includes stripes of intercalated metasediments and ocean-floor/back-arc gabbros and basalts. The Jequié Block, the third segment, is exposed in the SE-SSW area, being characterized by Archean granulitic migmatites with supracrustal inclusions and several charnockitic intrusions. The Serrinha Block (fourth segment) occurs to the NE, composed of orthogneisses and migmatites, which represent the basement of Paleoproterozoic greenstone belts sequences. During the Paleoproterozoic Transamazonian Orogeny, these four crustal segments collided, resulting in the formation of an important mountain belt. Geochronological constrains indicate that the regional metamorphism resulting from crustal thickening associated with the collision process took place around 2.0 Ga.
Megaspores from coals of the Triunfo Member, Rio Bonito Formation (Lower Permian), northeastern Paraná State, Brazil
Authors: RICARDI-BRANCO FRESIA , ARAI MITSURU , RÖSLER OSCAR
Published: April 2005

This paper presents the results of a detailed study of megaspores occurring in coal seams of the Triunfo Member, Rio Bonito Formation at Figueira, Paraná State, Brazil. This coal-bearing sequence accumulated in a marine delta system during the Early Permian. Four species are described and illustrated: Lagenoisporites triunfensis, L. scutiformis, Sublagenicula cf. brasiliensis, and Setosisporites cf. furcatus. Of these, the two species of Lagenoisporites are predominant. Relationships to other megaspore species are discussed; and the temporal and spatial distributions of the four species in the Paraná Basin are documented.
Topological equivalence for multiple saddle connections
Authors: ALONSO CLEMENTA , CAMACHO MARIA IZABEL , CANO FELIPE
Published: April 2005

We study the topological equivalence between two vector fields defined in the neighborhood of the skeleton of a normal crossings divisor in an ambient space of dimension three. We deal with singularities obtained from local ones by ambient blowing-ups: we impose thus the non-degeneracy condition that they are all hyperbolic without certain algebraic resonances in the set of eigenvalues. Once we cut-out the attractors, we get the result if the corresponding graph has no cycles. The case of cycles is of another nature, as the Dulac Problem in dimension three.
Positively curved 6-manifolds with simple symmetry groups
Authors: FANG FUQUAN
Published: April 2005

Let M be a simply connected compact 6-manifold of positive sectional curvature. If the identity component of the isometry group contains a simple Lie subgroup, we prove that M is diffeomorphic to one of the five manifolds listed in Theorem A.
The surface charge of trypanosomatids
Authors: SOUTO-PADRÓN THAÏS
Published: April 2005

The surface charge of trypanosomatids was evaluated by means of the binding of cationic particles, as visualized by electron microscopy and by direct measurements of the electrophoretic mobility of cells. The results obtained indicate that most of the trypanosomatids exhibit a negatively charged surface whose value is species specific and varies according to the developmental stages. Sialic acids associated with glycoproteins, glycolipids and phosphate groups are the major components responsible for the net negative surface charge of the trypanosomatids.
Modulators of axonal growth and guidance at the brain midline with special reference to glial heparan sulfate proteoglycans
Authors: CAVALCANTE LENY A. , GARCIA-ABREU JOSÉ , MOURA NETO VIVALDO , SILVA LUIZ CLAUDIO , WEISSMÜLLER GILBERTO
Published: April 2005

Bilaterally symmetric organisms need to exchange information between the left and right sides of their bodies to integrate sensory input and to coordinate motor control. Thus, an important choice point for developing axons is the Central Nervous System (CNS) midline. Crossing of this choice point is influenced by highly conserved, soluble or membrane-bound molecules such as the L1 subfamily, laminin, netrins, slits, semaphorins, Eph-receptors and ephrins, etc. Furthermore, there is much circumstantial evidence for a role of proteoglycans (PGs) or their glycosaminoglycan (GAG) moieties on axonal growth and guidance, most of which was derived from simplified models. A model of intermediate complexity is that of cocultures of young neurons and astroglial carpets (confluent cultures) obtained from medial and lateral sectors of the embryonic rodent midbrain soon after formation of its commissures. Neurite production in these cocultures reveals that, irrespective of the previous location of neurons in the midbrain, medial astrocytes exerted an inhibitory or non-permissive effect on neuritic growth that was correlated to a higher content of both heparan and chondroitin sulfates (HS and CS). Treatment with GAG lyases shows minor effects of CS and discloses a major inhibitory or non-permissive role for HS. The results are discussed in terms of available knowledge on the binding of HSPGs to interative proteins and underscore the importance of understanding glial polysaccharide arrays in addition to its protein complement for a better understanding of neuron-glial interactions.
Spatial resolution influence on the identification of land cover classes in the Amazon environment
Authors: PONZONI FLÁVIO J. , GALVÃO LÊNIO S. , EPIPHANIO JOSÉ C.N.
Published: April 2005

To evaluate the role played by the spatial resolution in distinguishing land cover classes in the Amazon region, different levels of spatial resolution (60, 100, 120, 200 and 250 meters) were simulated from a Landsat_5 Thematic Mapper (TM) image. Thematic maps were produced by visual interpretation from the original (30 x 30 meters) and simulated set of images. The map legend included primary forest, old and young woody secondary succession, and non-forest. The results indicated that for the discrimination between primary forest and non-forest, spatial resolution did not have great influence for pixel size equal or lower than 200 meters. The contrary was verified for the identification of old and young woody secondary vegetation due to their occurrence in small polygons. To avoid significant changes in the calculated area of these land cover types, a spatial resolution better than 100 meters is required. This result is an indication that the use of the future Brazilian remote sensing satellite (SSR-1) for secondary succession identification may be unreliable, especially for latitudes between S10° and S15° where critical areas of deforestation are located and pixel size is expected to vary within the same scene from 100 meters (S10°) to 200 meters (S15°).
Mid amphibolite facies metamorphism of harzburgites in the Neoproterozoic Cerro Mantiqueiras Ophiolite, southernmost Brazil
Authors: HARTMANN LÉO A. , CHEMALE-JÚNIOR FARID
Published: April 2005

Valuable information is retrieved from the integrated investigation of the field relationships, microstructure and mineral compositions of harzburgites from the Neoproterozoic Cerro Mantiqueiras Ophiolite. This important tectonic marker of the geological evolution of southernmost Brazilian Shield was thoroughly serpentinized during progressive metamorphism, because the oldest mineral assemblage is: olivine + orthopyroxene + tremolite + chlorite + chromite. This M1 was stabilized in mid amphibolite facies - 550-600ºC as calculated from mineral equilibria. No microstructural (e.g. ductile deformation of olivine or chromite) or compositional (e.g. mantle spinel) remnant of mantle history was identified. A metamorphic event M2 occurred in the low amphibolite facies along 100 m-wide shear zones, followed by intense serpentinization (M3) and narrow 1-3 m-wide shear zones (M4) containing asbestos.
Evaluation of the catalytic activity of lipases immobilized on chrysotile for esterification
Authors: Silva Jane E. S. , Jesus Paulo C.
Published: April 2005

In the present work, the ester synthesis in organic media catalyzed by lipases immobilized on chrysotile was studied. Lipases of different sources (Mucor javanicus, Pseudomonas cepacia, Rhizopus oryzae, Aspergillus niger and Candida rugosa) were immobilized on chrysotile, an inexpensive magnesium silicate, and used for esterification of hexanoic, octanoic and lauric acid with methanol, ethanol, 1-butanol and 1-octanol at 25ºC in hexane as solvent. The best results were obtained with Mucor javanicus lipase and lauric acid giving yields of 62-97% of ester.
Minimal surfaces in euclidean 3-space and their mean curvature 1 cousins in hyperbolic 3-space
Authors: Fujimori Shoichi
Published: April 2005

We show that the Hopf differentials of a pair of isometric cousin surfaces, a minimal surface in euclidean 3-space and a constant mean curvature (CMC) one surface in the 3-dimensional hyperbolic space, with properly embedded annular ends, extend holomorphically to each end. Using this result, we derive conditions for when the pair must be a plane and a horosphere.
Shrimp U-Pb age and Sr-Nd isotopes of the Morro do Baú mafic intrusion: implications for the evolution of the Arenópolis volcano-sedimentary sequence, Goiás Magmatic Arc
Authors: Pimentel Márcio M. , Hollanda Maria Helena B. M. , Armstrong Richard
Published: April 2005

The Arenópolis volcano-sedimentary sequence is located in the southern part of the Goiás Magmatic Arc and includes a ca. 900 Ma calc-alkaline arc sequence made of volcanic rocks ranging in composition from basalts to rhyolites, metamorphosed under greenschist to amphibolite facies. Small calc-alkaline gabbro to granite sub-volcanic bodies are also recognized. The Morro do Baú intrusion is the largest of these intrusions, and is made of gabbros and diorites. Zircon grains separated from one gabbro sample and analyzed by SHRIMP I yielded the mean 206Pb/238U age of 890 +/- 8 Ma, indicating that the intrusion is roughly coeval or only slightly younger than the Arenópolis volcanics. Contrary to the metavolcanics, which are juvenile, the Nd isotopic composition of the Morro do Baú gabbro indicates strong contamination with archean sialic material (T DM of 2.8 Ga and EpsilonNd(T) of -9.7), represented in the area by an allochthonous sliver of archean/paleoproterozoic gneisses (Ribeirão gneiss) which are the country-rocks for the gabbro/dioritic intrusion. The emplacement age of ca. 890 Ma represents a minimum age limit for the tectonic accretion of the gneiss sliver to the younger rocks of the Arenópolis sequence. The data suggest that this happened early in the evolution of the Goiás Magmatic Arc, between ca. 920 and 890 Ma.
Sm-Nd age of the fazenda brasileiro gabbro, Bahia, Brazil: example of robust behavior of the Sm-Nd isotopic system under extreme hydrothermal alteration
Authors: Pimentel Márcio M. , Silva Maria da Glória
Published: April 2005

The Fazenda Brasileiro gold mineralization is hosted by a gabbroic sill, intrusive into metavolcanicmetasedimentary rocks of the Rio Itapicuru Greenstone Belt, São Francisco Craton. The 2.05 Ga old mineralization is associated with intense shearing and hydrothermal alteration, and the host gabbro is altered to a series of rocks rich in sericite, chlorite, actinolite, carbonate and quartz. Twelve whole-rock samples of the gold mineralization, representing varied degrees of alteration, from rocks with preserved igneous textures to the ore (quartz-carbonate-sulfide-chlorite), were studied by the Sm-Nd method. All analytical points resulted in an isochron (MSWD = 1.9) indicating the age of 2142 +/- 47 Ma (1s) and Epsilon Nd (T) of +1.2. Chlorite-sericite-carbonate rich hydrothermal rocks indicate the age of 2148 +/- 57 Ma and Epsilon Nd (T) of +1.1. The positive Epsilon Nd (T) suggest limited or no contamination with older continental crust, compatible with an oceanic setting for the tholeiites. Combined withREEdata, the Sm-Nd isotopic results reveal that the hydrothermal alteration, although intense, was unable to alter significantly the Sm/Nd ratios of the original igneous rocks and did not cause important scatter of the analytical points, providing a rare example of robust behavior of the isotopic system, even under intense hydrothermal alteration.
A metric property of umbilic points
Authors: Garcia Ronaldo , Sotomayor Jorge
Published: April 2005

In the space of cubic forms of surfaces, regarded as a G-space and endowed with a natural invariant metric, the ratio of umbilic points with a negative index to those with a positive index is evaluated in terms of the asymmetry of the metric, defined here. This work contains also a section with references pertinent to umbilic points and one with a discussion of a connection of the above defined ratio with that reported in 1977 by Berry and Hannay in the domain of Statistical Physics.
Importance of CD8 T cell-mediated immune response during intracellular parasitic infections and its implications for the development of effective vaccines
Authors: Rodrigues Mauricio M. , Boscardin Silvia B. , Vasconcelos José R. , Hiyane Meire I. , Salay Gerson , Soares Irene S.
Published: April 2005

Obligatory intracellular parasites such as Plasmodium sp, Trypanosoma cruzi, Toxoplasma gondii and Leishmania sp are responsible for the infection of hundreds of millions of individuals every year. These parasites can deliver antigens to the host cell cytoplasm that are presented through MHC class I molecules to protective CD8 T cells. The in vivo priming conditions of specific CD8 T cells during natural infection are largely unknown and remain as an area that has been poorly explored. The antiparasitic mechanisms mediated by CD8 T cells include both interferon-g-dependent and -independent pathways. The fact that CD8 T cells are potent inhibitors of parasitic development prompted many investigators to explore whether induction of these T cells can be a feasible strategy for the development of effective subunit vaccines against these parasitic diseases. Studies performed on experimental models supported the hypothesis that CD8 T cells induced by recombinant viral vectors or DNA vaccines could serve as the basis for human vaccination. Regimens of immunization consisting of two different vectors (heterologous prime-boost) are much more efficient in terms of expansion of protective CD8 T lymphocytes than immunization with a single vector. The results obtained using experimental models have led to clinical vaccination trials that are currently underway.
U-Pb evidence for late Neoarchean crustal reworking in the Southern São Francisco Craton (Minas Gerais, Brazil)
Authors: Campos José C.S. , Carneiro Maurício A. , Basei Miguel A.S.
Published: April 2005

The Passa Tempo Metamorphic Complex is one of several metamorphic complexes that form the Archean sialic crust of the southern São Francisco Craton. It encompasses hypersthene-bearing gneissic rocks, with subordinateNW- or EW-trending mafic-ultramafic bodies and granodioritic to alkali-granitic, weakly foliated, and light-colored granitoids. These granitoids are the product of generalized migmatization that followed granulite-facies metamorphism. To determine the ages of the granulite-facies metamorphism and granitoid genesis, we obtained U-Pb ages on zircon extracted from the mesosome and leucosome of the migmatitic gneisses. For the mesosome, a discordia that intercepts Concordia at 2622 ± 18 Ma is interpreted as a minimum age for granulite-facies metamorphism. For the leucosome, the upper intercept of discordia at 2599 ± 45 Ma corresponds to migmatization and granitoid genesis. Contemporaneous metamorphism and magmatism have been documented elsewhere in the São Francisco Craton, especially in the southern portion, demonstrating vast and vigorous reworking of sialic crust by the end of the Neoarchean.
Dirac's æther in curved spacetime-II: the geometric amplification of the cosmic magnetic induction
Authors: Carvalho Marcelo , Oliveira Alexandre L. , Rabaça Carlos R.
Published: April 2005

We search for an amplification mechanism of the seed cosmic magnetic induction by studying a new version of the Dirac's æther in a curved cosmological background. We find that the variation of the scale factor R(t) with cosmic time brings to the magnetic field the desired effect of amplification, that we call geometric amplification.
Structure and biological functions of fungal cerebrosides
Authors: Barreto-Bergter Eliana , Pinto Marcia R. , Rodrigues Marcio L.
Published: April 2005

Ceramide monohexosides (CMHs, cerebrosides) are glycosphingolipids composed of a hydrophobic ceramide linked to one sugar unit. In fungal cells, CMHs are very conserved molecules consisting of a ceramide moiety containing 9-methyl-4,8-sphingadienine in amidic linkage to 2-hydroxyoctadecanoic or 2-hydroxyhexadecanoic acids, and a carbohydrate portion consisting of one residue of glucose or galactose. 9-Methyl 4,8-sphingadienine-containing ceramides are usually glycosylated to form fungal cerebrosides, but the recent description of a ceramide dihexoside (CDH) presenting phytosphingosine in Magnaporthe grisea suggests the existence of alternative pathways of ceramide glycosylation in fungal cells. Along with their unique structural characteristics, fungal CMHs have a peculiar subcellular distribution and striking biological properties. In Pseudallescheria boydii, Candida albicans, Cryptococcus neoformans, Aspergillus nidulans, A. fumigatus, and Schizophyllum commune, CMHs are apparently involved in morphological transitions and fungal growth. The elucidation of structural and functional aspects of fungal cerebrosides may therefore contribute to the design of new antifungal agents inhibiting growth and differentiation of pathogenic species.
Permian plants from the Chutani Formation (Titicaca Group, Northern Altiplano of Bolivia): II. The morphogenus Glossopteris
Authors: Iannuzzi Roberto , Vieira Carlos E. L. , Guerra-Sommer Margot , Díaz-Martínez Enrique , Grader George W.
Published: April 2005

Fossil plants belonging to the morphogenera Glossopteris, Pecopteris and Asterotheca were collected from the upper part of the Chutani Formation (Titicaca Group), near the town of San Pablo de Tiquina, on the southeastern shore of Lake Titicaca (northern Altiplano, Bolivia). This paper presents the first description of specimens of the morphogenus Glossopteris from Bolivia. The Bolivian specimens of Glossopteris consist of poorly-preserved impressions, although they present the diagnostic features of this morphogenus. They are fragments of leaves with secondary veins of taeniopterid-type, typical of glossopterids from Late Permian deposits of Gondwana. The only species of Pecopteris confirmed in the first part of this study, i.e. P. dolianitii Rösler and Rohn (see Vieira et al. 2004), was previously reported from the Late Permian beds of the Rio do Rasto and Estrada Nova formations in the Paraná Basin (southern Brazil). Therefore, a Late Permian age is proposed for the fossil plant-bearing beds of the Chutani Formation based on the analyzed assemblage. The phytogeographic implications of this new find are briefly analyzed.
Equity, quality and relevance in higher education in Brazil
Authors: Schwartzman Simon
Published: April 2005

Brazilian higher education has doubled its size in the 1990s, going from 1.5 million to more than 3 million students in the period. This expansion was mostly due to the growth of private education, which, in 2002, accounted for about two thirds of the enrollment. Is expansion making higher education more accessible to persons coming from the poorer segments of society? Is the quality of higher education suffering by the speed of this expansion? Is Brazil educating enough qualified persons to attend to the country's needs to participate in the new, knowledge-intensive and global economy? What public policies should be implemented, in order to foster the values of social equity and relevance? What are the policy implications of these developments? This article looks at the available evidence, and suggests some answers to these questions.
Identification and analysis of vocal communication pathways in birds through inducible gene expression
Authors: Mello Claudio V.
Published: April 2005

The immediate-early gene zenk is an activity-dependent gene highly induced in auditory processing or vocal motor control brain areas when birds engage in hearing or producing song, respectively. Studies of the expression of zenk in songbirds and other avian groups will be reviewed here briefly, with a focus on how this analysis has generated new insights on the brain pathways and mechanisms involved in perceptual and motor aspects of vocal communication and vocal learning.
Bits and q-bits as versatility measures
Authors: Piqueira José R.C.
Published: April 2005

Using Shannon information theory is a common strategy to measure any kind of variability in a signal or phenomenon. Some methods were developed to adapt information entropy measures to bird song data trying to emphasize its versatility aspect. This classical approach, using the concept of bit, produces interesting results. Now, the original idea developed in this paper is to use the quantum information theory and the quantum bit (q-bit) concept in order to provide a more complete vision of the experimental results.
Hypersurfaces with constant mean curvature and two principal curvatures in n+1
Authors: Alías Luis J. , Almeida Sebastião C. de , Brasil Jr. Aldir
Published: April 2005

In this paper we consider compact oriented hypersurfaces M with constant mean curvature and two principal curvatures immersed in the Euclidean sphere. In the minimal case, Perdomo (Perdomo 2004) andWang (Wang 2003) obtained an integral inequality involving the square of the norm of the second fundamental form of M, where equality holds only if M is the Clifford torus. In this paper, using the traceless second fundamental form of M, we extend the above integral formula to hypersurfaces with constant mean curvature and give a new characterization of the H(r)-torus.
A relation between the right triangle and circular tori with constant mean curvature in the unit 3-sphere
Authors: Barros Abdênago
Published: April 2005

In this note we will show that the inverse image under the stereographic projection of a circular torus of revolution in the 3-dimensional euclidean space has constant mean curvature in the unit 3-sphere if and only if their radii are the catet and the hypotenuse of an appropriate right triangle.
Flavonoids from Lonchocarpus muehlbergianus
Authors: Magalhães Aderbal F. , Tozzi Ana M.G.A. , Magalhães Eva G. , Blanco Ivani S. , Soriano Maria-Del-Pilar C.
Published: April 2005

The light petroleum extract from the roots of Lonchocarpus muehlbergianus Hassl contained nine flavonoids, including six new ones. These are 2,4-cis-2,4,5,8-tetramethoxy-(2´´,3´´:6,7)-furanoflavan; 2,4-cis-4-hydroxy-2,5,8-trimethoxy-(2´´,3´´:6,7)-furanoflavan; 2,4-cis-2-prenyloxy-4,5,8-trimethoxy-(2´´,3´´:6,7)-fu-ranoflavan; 2,4-cis-2-prenyloxy-4-hydroxy-5,8-dimethoxy-(2´´,3´´:6,7)-furanoflavan; 2',5',6'-trimethoxy-9-(1,1-dimethylallyoxy)-[2´´,3´´:3´,4´]-furanochalcone; 5,6-dimethoxy-(2´´,3´´:7,8)-furanoflavone, identi-fied by analysis of their spectral data (UV, IR, ¹H and 13C NMR, 2D-NMR, NOE and MS). The natural occurrence of 2,4-dioxygenated flavan derivatives is being reported for the first time. Quantitative analysis of the petrol extract, by using reversed-phase HPLC, showed that the most abundant flavonoid in the extract is 2,4-cis-2,4,5,8- tetramethoxy-(2´´,3´´:6,7)-furanoflavan.
Overview of genotypic and clinical profiles of human immunodeficiency virus type 1-infected children in Rio de Janeiro, Brazil
Authors: Machado Elizabeth S. , Lambert John S. , Afonso Adriana O. , Cunha Silvia M. , Oliveira Ricardo H. , Tanuri Amilcar , Sill Anne M. , Soares Marcelo A.
Published: April 2005

Although mother-to-child HIV transmission prevention has slowed down pediatric HIV infection in developed countries, large numbers of infants still become infected in developing nations. Data on pediatric HIV infection is however largely scarce. In this study, we have overviewed clinical, laboratory and genotypic data from a large cohort of HIV-infected infants regularly followed at two pediatric HIV outpatient clinics in Rio de Janeiro, Brazil. Children on antiretroviral therapy, as well as drug-naïve, newly diagnosed infants were analyzed. Prevalence of drug resistance mutations, as well as immunological and virological responses to therapy were evaluated. Additionally, HIV-1 subtype frequencies and their distribution over the course of the epidemic were studied. We have found a high prevalence of mutations among ARV-experienced children, whereas mutations were absent in the drug-naïve group. Despite the high levels of resistance among treated infants, an important improvement of their immunological status was observed. HIV-1 subtype distribution followed the trends of the adult population, with the appearance of non-B subtypes and recombinant forms after 1990. To our knowledge, this is the largest pediatric cohort ever analyzed in Brazil, and the data provided is of paramount importance to a better understanding of HIV/AIDS evolution in pediatric settings.
On the patterns of principal curvature lines around a curve of umbilic points
Authors: Garcia Ronaldo , Sotomayor Jorge
Published: April 2005

In this paper is studied the behavior of principal curvature lines near a curve of umbilic points of a smooth surface.
Hypervalent Iodine Chemistry in Synthesis: Scope and New Directions
Authors: Wirth Thomas
Published: April 2005

The impressive development of hypervalent iodine chemistry in recent years is reflected by the number of publications in this area. Although the synthesis of the first hypervalent iodine compound dates back more than 100 years, the investigation of the reactivities of these compounds and their efficient use as metal‐free reagents in organic synthesis is still ongoing. This contribution summarizes recent achievements and highlights key findings and developments that will influence future research and lead to novel applications of hypervalent iodine reagents in synthesis.
Synthesis and Characterization of (NH4) 2CuBr2Cl2×2H2O Crystals.
Authors: Amirthaganesan G. , Kandhaswamy M. A. , Srinivasan V.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
First Example of Chiral N‐Heterocyclic Carbenes as Catalysts for Kinetic Resolution.
Authors: Suzuki Yumiko , Yamauchi Kaori , Muramatsu Kazuyuki , Sato Masayuki
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Facile Synthesis of Enantiopure 1,1′‐Spirobiindan‐7,7′‐diol and Its 4,4′‐Derivatives: Application in Enantioselective Addition of Diethylzinc to Aromatic Aldehydes.
Authors: Li Zhian , Liang Xinmiao , Wan Boshun , Wu Fan
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Reactions with Hydrazonoyl Halides. Part 42. Synthesis of Some New 2,3‐Dihydro‐1,3,4‐thiadiazoles, 2,3‐Dihydro‐1,3,4‐selenadiazoles and Triazolino[4,3‐a]pyrimidines.
Authors: Abdelhamid Abdou O. , Alkhodshi Mohamed A. M.
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
α‐Hydroxylation of Carbonyls Using Iodine.
Authors: Zacuto Michael J. , Cai Dongwei
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
Studies on the Base‐Promoted Conversion of Conjugated Alkynyl Esters to α‐Allenyl Esters.
Authors: Lepore Salvatore D. , He Yuanjun , Damisse Pamela
Published: April 2005

For Abstract see ChemInform Abstract in Full Text.
1‐Alkynyl(aryl)(tetrafluoroborato)‐λ3‐bromanes as Highly Efficient Michael Acceptors: Uncatalyzed Conjugate Addition of 1‐Alkynyl(trialkyl)stannanes to Yield Symmetrical and Unsymmetrical 1,3‐Butadiynes.
Authors: Ochiai Masahito , Nishi Yoshio , Goto Satoru , Frohn Hermann J.
Published: April 2005

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Stereochemistry of Contiguous Cyclopropane Formation from Cascade Cyclization of a Skipped Dienyl Homoallyl Triflate.
Authors: Lincoln Christopher M. , White James D. , Yokochi Alexandre F. T.
Published: April 2005

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Bromination of Azulene Derivatives with Sodium Monobromoisocyanurate.
Authors: Sumida Toshiaki , Kikuchi Shigeru , Imafuku Kimiaki
Published: April 2005

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A New Method for the Synthesis of β‐Amino—β′‐Hydroxy Ketones by the Samarium(II) Iodide‐Mediated Aldol Reaction of Aldehydes with Aryl or Alkyl Aziridinyl Ketones.
Authors: Mukaiyama Teruaki , Ogawa Yasuyuki , Kuroda Kiichi
Published: April 2005

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New Approaches to β‐Trifluoromethylated Enone Derivatives.
Authors: Jeong In Howa , Jeon Sung Lan , Kim Myong Sang , Kim Bum Tae
Published: April 2005

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Discovery of a Novel, Potent and Selective Human β3‐Adrenergic Receptor Agonist.
Authors: Nakajima Yutaka , Hamashima Hitoshi , Washizuka Ken‐Ichi , Tomishima Yasuyo , Ohtake Hiroaki , Imamura Emiko , Miura Toshiko , Kayakiri Hiroshi , Kato Masayuki
Published: April 2005

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Iron Tricarbonyl Stabilized Pentadienyl Cation as Initiator for Cascade Polycyclizations: A Diastereoselective Entry into Octahydrophenanthrenes.
Authors: Pearson Anthony J. , Ghidu Victor P.
Published: April 2005

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Synthesis of N‐[2‐Benzyloxy‐5‐(2‐oxiranyl)phenyl]formamide: Formal Synthesis of Formoterol.
Authors: Mereyala Hari Babu , Sambaru Kalyani
Published: April 2005

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Reaction of Allyl Phenylcarbamate with Benzaldehyde Phenylhydrazones in the Presence of N‐Chlorobenzenesulfonamide Sodium Salt.
Authors: Velikorodov A. V.
Published: April 2005

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Direct Formation of 2,3,5‐Trichloropyridine and Its Nucleophilic Displacement Reactions in Ionic Liquid.
Authors: Zhong Ping , Hu Huanan , Guo Shengrong
Published: April 2005

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Synthesis and Structural Study of 3‐Anisyl‐4‐(4′‐pyridyl)(pyridinium)thieno[2,3‐b]thienophenes.
Authors: Mashraqui Sabir H. , Hariharasubrahmanian Harini , Ashraf Mohamed , Sangvikar Yogesh
Published: April 2005

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Synthesis of 15H‐Isoquino[2′,3′:3,4]imidazo[2,1‐b]quinazoline‐7,13,15‐triones and 14H‐isoquino[2′,3′:3,4]imidazo[2,1‐b]benzo[g]quinazoline‐8,14,16‐trione as New Polycyclic Fused‐Ring Systems.
Authors: Khodair Ahmed I. , Gesson Jean‐Pierre , El‐Ashry El‐Sayed H.
Published: April 2005

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Interaction of Cyclic Schiff′s Bases with 2‐Methylthiopyrimidine‐4,6‐dione Enol Acetate. Synthesis of 5‐(2‐Acetyl‐6,7‐dimethoxy‐1,2,3,4‐tetrahydro‐1‐isoquinolyl) ‐6‐hydroxy‐2‐methylthio‐1,4‐dihydro‐4‐pyrimidinones.
Authors: Gulyakevich O. V. , Krasnov K. A. , Mikhal'chuk A. L. , Akhrem A. A.
Published: April 2005

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KF‐Alumina Catalyzed One‐Pot Synthesis of Pyrido[2,3‐d]pyrimidine Derivatives.
Authors: Wang Xiang‐shan , Zeng Zhao‐sen , Shi Da‐qing , Wei Xian‐yong , Zong Zhi‐min
Published: April 2005

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An Unprecedented Dimerization of 1,2,3‐Butatriene Catalyzed by Palladium Complexes.
Authors: Suzuki Noriyuki , Tezuka Hidekazu , Fukuda Yoshiyuki , Yoshida Hajime , Iwasaki Masakazu , Saburi Masahiko , Tezuka Meguru , Chihara Teiji , Wakatsuki Yasuo
Published: April 2005

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Synthesis of Novel Aminophosphonic Derivatives of Benzo‐15‐crown‐5 Ether.
Authors: Boduszek Bogdan , Luboch Elzbieta
Published: April 2005

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The Stereochemical Behavior of Terephthalic Schiff Bases in Addition of Dialkyl or Diaryl Phosphites.
Authors: Lewkowski Jaroslaw
Published: April 2005

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Cyclopropanation of Betulin and Its Diacetate with Dihalocarbenes.
Authors: Komissarova N. G. , Belenkova N. G. , Shitikova O. V. , Spirikhin L. V. , Yunusov M. S.
Published: April 2005

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Synthesis of Symmetric Bis(imidazole‐4,5‐dicarboxamides) Substituted with Amino Acids.
Authors: Wiznycia Alexander V. , Rush Jeremy , Baures Paul W.
Published: April 2005

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Synthesis, Antitumor and Antimicrobial Activities of New Peptidyl Derivatives Containing the 1,3‐Benzodioxole System.
Authors: Leite Ana Cristina Lima , da Silva Kezia Peixoto , de Souza Ivone , de Araujo Janete Magali , Brondani Dalci Jose
Published: April 2005

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Direct Solution Synthesis of Intermetallic AuCu and AuCu3 Nanocrystals and Nanowire Networks.
Authors: Sra Amandeep K. , Ewers Trevor D. , Schaak Raymond E.
Published: April 2005

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The Development of Efficient Catalysts for Palladium‐Catalyzed Coupling Reactions of Aryl Halides
Authors: Zapf Alexander , Beller Matthias
Published: April 2005

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Quasi‐Periodic Organization in Soft Self‐Assembling Matter
Authors: Mehl Georg H.
Published: April 2005

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Metal‐Mediated and Metal‐Catalyzed Hydrolysis of Nitriles
Authors: Kukushkin Vadim Yu. , Pombeiro Armando J. L.
Published: April 2005

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Reaction Mechanisms. Part 1. Radical and Radical Ion Reactions
Authors: Tanko J. M.
Published: April 2005

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Reaction Mechanisms. Part 2. Polar Reactions
Authors: Dalby Kevin N.
Published: April 2005

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Template‐Induced Enantioselective Photochemical Reactions in Solution
Authors: Grosch Benjamin , Bach Thorsten
Published: April 2005

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Enantiodifferentiating Photosensitized Reactions
Authors: Inoue Yoshihisa
Published: April 2005

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Transition Metal Chemistry of Glucose Oxidase, Horseradish Peroxidase, and Related Enzymes
Authors: Ryabov Alexander D.
Published: April 2005

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Quadrupole Ion Trap Studies of Fundamental Organic Reactions
Authors: Gronert Scott
Published: April 2005

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Direct high‐performance liquid chromatographic enantioseparation of β‐lactam stereoisomers
Authors: Péter Antal , Árki Anita , Forró Enikő , Fülöp Ferenc , Armstrong Daniel W.
Published: April 2005

High‐performance liquid chromatographic methods were developed for the separation of the enantiomers of 12 β‐lactams. Direct separations were performed on chiral stationary phases (CSPs) containing cellulose‐tris‐3,5‐dimethylphenyl carbamate (Chiralcel OD‐RH and OD‐H columns), the macrocyclic glycopeptide antibiotic teicoplanin (Chirobiotic T column), or teicoplanin aglycone (Chirobiotic TAG column) as the chiral selector. It was clearly established that, with teicoplanin‐based columns, the teicoplanin aglycone was most often responsible for the enantioseparation of the β‐lactams. The difference in enantioselective free energy between the aglycone CSP and the teicoplanin CSP was in the range between 0.02 and 0.97 kJ mol−1 for these β‐lactam stereoisomer separations. The separations were carried out with high selectivity and resolution, and the method was therefore suitable for monitoring of the enantiomeric excess after chiral synthesis. The Chirobiotic and Chiralcel columns appear to be highly complementary to one another. The best separation of this class of β‐lactam compound could be obtained using the Chirobiotic TAG in the polar‐organic mode plus the Chiralcel OD‐H in the normal‐phase mode. The elution sequence was also determined. Chirality 17:193–200, 2005. © 2005 Wiley‐Liss, Inc.
On Differences between Hydrogen Bonding and Improper Blue‐Shifting Hydrogen Bonding
Authors: Zierkiewicz Wiktor , Jurečka Petr , Hobza Pavel
Published: April 2005

Twenty two hydrogen‐bonded and improper blue‐shifting hydrogen‐bonded complexes were studied by means of the HF, MP2 and B3LYP methods using the 6‐31G(d,p) and 6—311++G(d,p) basis sets. In contrast to the standard H bonding, the origin of the improper blue‐shifting H bonding is still not fully understood. Contrary to a frequently presented idea, the electric field of the proton acceptor cannot solely explain the different behavior of the H‐bonded and improper blue‐shifting H‐bonded complexes. Compression of the hydrogen bond due to different attractive forces—dispersion or electrostatics—makes an important contribution as well. The symmetry‐adapted perturbation theory (SAPT) has been utilized to decompose the total interaction energy into physically meaningful contributions. In the red‐shifting complexes, the induction energy is mostly larger than the dispersion energy while, in the case of blue‐shifting complexes, the situation is opposite. Dispersion as an attractive force increases the blue shift in the blue‐shifting complexes as it compresses the H bond and, therefore, it increases the Pauli repulsion. On the other hand, dispersion in the red‐shifting complexes increases their red shift.
Trajectory tracking control of mobile robot by time‐based spline approach
Authors: Miyata Junichi , Murakami Toshiyuki , Ohnishi Kouhei
Published: April 2005

A mobile robot must move without unacceptable rapid motion. To address this issue, we propose a preview controller using the time‐based spline approach. With this approach, it is also important to plan an adequate trajectory. Here an approach to trajectory planning which has the trajectory determination strategy via a virtual manipulator is proposed. Numerical and experimental results are shown to confirm the proposed algorithm. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(4): 65–71, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10349
Comparative studies on magnetic flux relaxations of varied spherical toroids produced by co‐helicity merging
Authors: Tsuruda Mayuko , Ono Yasushi , Katsurai Makoto
Published: April 2005

The co‐helicity merging operations of compact toroid (CT) and spherical tokamak (ST) have been performed with external toroidal fields in the CT/ST merging device TS‐4. The low‐q (safety factor) CT merging as the compact RFP merging and the spheromak merging show the flux conversion from toroidal to poloidal in the course of the reconstruction of the Taylor force free state. The relaxation to the Taylor state proceeds through the following three states: (1) axisymmetric merging with increasing toroidal flux; (2) increase in the poloidal flux Ψ; and (3) relaxation to the Taylor state. The high‐q ST merging shows different relaxation process from those of the compact RFP and the spheromak mergings. Increases in Ψ were not clearly observed in the ST merging. The measured eigenvalues λ show that ST's, especially high‐q ST's, approach a unique intrinsic equilibrium state that has a λ proportional to Ψ with a longer lifetime than that of CT's. When external toroidal field is set in a certain range between the low‐q operation and the high‐q operation for ST's, an abnormal phenomenon was found in the ST formation, namely, a drastic decrease in the plasma lifetime. This phenomenon is characterized by very weak poloidal flux generations during the initial plasma production phase and the subsequent plasma separation phase when the plasma starts detaching from the flux core. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(4): 7–15, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20069
Realization and location control of attenuation poles by bandpass filters using mixed resonators
Authors: Wada Kouji , Ohno Takanobu , Hashimoto Osamu
Published: April 2005

This paper describes the improvement of the skirt characteristics of a bandpass filter (BPF) by using mixed tapped resonators. In this paper, we try to examine the transmission characteristics of the BPFs with a function to control the number of attenuation poles based on the use of a λ/2 resonator and a λ/4 resonator as the basis of the distributed constant line resonators. As a result, we have confirmed that realization of the attenuation poles has a greater effect than choice of the number of resonators or choice and location control of the numbers of realized poles. The miniaturization of the presented BPF is also accomplished as well as location of the attenuation poles mentioned above. It has been confirmed that our proposal enables the control of the number of attenuation poles of the BPF. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(4): 36–46, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20074