Extreme thermopower anisotropy and interchain transport in the quasi-one-dimensional metal Li0.9Mo6O17.

Thermopower and electrical resistivity measurements transverse to the conducting chains of the quasi-one-dimensional metal Li0.9Mo6O17 are reported in the temperature range 5≤T≤500 K. For T≥400 K the interchain transport is determined by thermal excitation of charge carriers from a valence band ∼0.14 eV below the Fermi level, giving rise to a large, p-type thermopower that coincides with a small, n-type thermopower along the chains. This dichotomy-semiconductorlike in one direction and metallic in a mutually perpendicular direction-gives rise to substantial transverse thermoelectric effects and a transverse thermoelectric figure of merit among the largest known for a single compound.

Chromatography of Solanum habrochaites extracts with the first record of the docosanoate, hexadecanoate and octadecanoate ethyls in this plant and in Solanaceae.

The increasing need for sustainable alternatives to synthetic insecticides has driven the analysis of extracts from Solanum habrochaites, a wild tomato, through fractionated column chromatography. Potential bioactive compounds for pest management, a clean and promising biotechnological solution, have been reported from this plant. The objective is to provide detailed gas chromatography data, including peaks, structural formulas, and retention indices for the extracts of S. habrochaites aerial parts. Column chromatographic analysis was conducted with five fractions (F1, F2, F5, F3, and F4) of S. habrochaites extracts. Long-chain hydrocarbons such as hexadecanoic acid and docosano were identified in the F1 fraction; fatty acid esters, including hexadecanoate and octadecenoate ethyls in the F2 and methyl ketones, with tridecan-2-one as the major component in the F5, while no identifiable compounds were disclosed in the F3 and F4 fractions. The column chromatography provided valuable insights into compounds in the F1, F2, and F5 fractions of S. habrochaites extracts, highlighting fatty acid esters, long-chain hydrocarbons, and methyl ketones. The bioactive compounds, from extracts of this plant, including the first record of the docosanoate, hexadecanoate and octadecanoate ethyls in S. habrochaites and Solanaceae, reinforces their promising biological application in different areas of science.

Giant Nernst effect and bipolarity in the quasi-one-dimensional metal Li0.9Mo6O17.

The Nernst coefficient for the quasi-one-dimensional metal, Li{0.9}Mo{6}O{17}, is found to be among the largest known for metals (ν≃500 µV/KT at T∼20 K), and is enhanced in a broad range of temperature by orders of magnitude over the value expected from Boltzmann theory for carrier diffusion. A comparatively small Seebeck coefficient implies that Li{0.9}Mo{6}O{17} is bipolar with large, partial Seebeck coefficients of opposite sign. A very large thermomagnetic figure of merit, ZT∼0.5, is found at high field in the range T≈35-50 K.

Observation of a martensitic structural distortion in V, Nb, and Ta.

Thermal-expansion measurements of the Group 5 elements V, Nb, and Ta reveal a structural distortion below 300 K. Data for single-crystalline Nb and Ta display anisotropic thermal expansion, martensitic in character, that is inconsistent with cubic crystal structures at low temperature. Published results on V show similar behavior. Interstitial impurities suppress the transition.

Simple analytical method for determining electrical resistivity and sheet resistance using the van der Pauw procedure.

This work reports an analytical method for determining electrical resistivity (ρ) and sheet resistance (RS) of isotropic conductors. The method is compared with previous numerical solutions and available experimental data showing a universal behavior for isotropic conductors. An approximated solution is also reported allowing one to easily determine ρ and RS for samples either with regular or arbitrary shapes.

Metabolic profiling and correlation analysis for the determination of killer compounds of proliferating and clonogenic HRT-18 colon cancer cells from Lafoensia pacari.

ETHNOPHARMACOLOGICAL RELEVANCE: Lafoensia pacari A. St.-Hil., belonging to the family Lythraceae and popularly known as 'dedaleira' and 'mangava-brava,' is a native tree of the Brazilian Cerrado, and its barks have been traditionally used as a tonic to treat inflammatory conditions, particularly related to gastric ulcers, wounds or fevers and various types of cancer. AIM OF THE STUDY: We have previously demonstrated the apoptogenic effects of the methanolic extract of L. pacari using various cancer cell lines. In the present study, this extract has been partitioned into fractions to identify the components that might be responsible for the apoptogenic effects using HRT-18 cells, which have been previously demonstrated to be sensitive to this extract. MATERIALS AND METHODS: A standard methanolic extract was prepared and fractionated by centrifugal partition chromatography. The fractions were submitted to cytotoxicity and clonogenic assays to monitor the effects in parallel with LC-DAD-MS and statistical analyses to suggest the potential bioactive compounds. RESULTS: Besides ellagic acid, the primary constituent of the plant and also the biomarker of the species, punicalin, pedunculagin and punicalagin isomers, catechin and ellagic acid derivatives were putatively identified. CONCLUSIONS: The barks of L. pacari are rich in ellagic acid and various hydrolysable tannins, some of which were reported for the first time in this species, such as punicalagin and ellagitannins. This mixture of substances had the ability to kill proliferating cells and abrogate the growth of clonogenic cells in a similar manner shown by the methanolic extract of our previous study. The collective data reported herein suggest that the biological activities of the L. pacari barks used by population to treat cancer conditions are due to the apoptogenic effects promoted by a mixed content of ellagitannins.

Passiflora actinia Hooker extracts and fractions induce catalepsy in mice.

Leaves from several Passiflora species are largely employed in the Brazilian folk medicine for its anxiolytic and sedative properties. In behavioral studies, to analyze the tranquillizer action of Passiflora actinia Hooker, it was noteworthy that animals treated with the hydroethanol (HE) and methanol (ME) extracts presented an abnormal postural immobility compared to control animals. That observation led to an investigation of the effects of HE and its fractions on evaluation of catalepsy in mice. The results showed that HE extract, methanol extract, the sequent aqueous crude fractions (AF), and fa, fb and fc chromatographic fractions obtained from Passiflora actinia induced catalepsy in mice. Apparently, the active principles responsible for catalepsy are present in all of the fractions of the extract.

Antimicrobial activity of alkaloidal fraction from barks of Himatanthus lancifolius.

The alkaloidal fraction from Himatanthus lancifolius barks demonstrated a broad-spectrum in vitro antimicrobial activity for most of the Gram (+) and Gram (-) tested microorganisms.

In vitro antioxidant activity of species collected in Paraná.

Hydroalcoholic extracts of 10 medicinally used species collected from the area covered by a reservoir due to a dam built for the Salto Caxias Hydro-electric power plant in the State of Paraná, Southern Brazil, and Casearia sylvestris, were investigated for their potential antioxidant activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) free radicals and by the phosphomolybdenum method. The extract of Bauhinia microstachya was found to be the most potent in both models.

Dimensional crossover in the purple bronze Li0.9Mo6O17.

Thermal expansion of Li0.9Mo6O17 is a-axis dominated which reduces the separation of the conducting chains at low temperature enhancing the interchain coupling. This destabilizes the Luttinger-liquid fixed point leading to an electronic charge- (or spin-) density wave dominated by Coulomb repulsion, as predicted by theories for Luttinger liquids.

O progresso da pesquisa sobre o gênero Baccharis, Asteraceae: I - Estudos botânicos / Research progress on the genus Baccharis, Asteraceae: I - Botanical studies

Baccharis é um importante gênero da família Asteraceae que compreende aproximadamente 500 espécies, todas americanas, das quais aproximadamente 120 ocorrem no Brasil. Muitos autores como De Candolle, Baker, Heering, Cuatrecasas, Ariza Espinar, Barroso e Giuliano têm tentado estruturar uma adequada divisão do gênero em subgêneros e seções. Espécies desse gênero são importantes economicamente para o homem, pois ajudam no combate à erosão e podem ser utilizadas como plantas ornamentais, mas também podem apresentar-se como pragas de difícil combate em pastagens, podendo intoxicar o gado. Contudo, o destaque maior está na medicina, onde vários representantes são utilizados popularmente. Nesse contexto várias espécies têm sido investigadas contribuindo para a elucidação morfoanatômica e para o controle de qualidade.

Baccharis is an important genus of the Asteraceae family, which comprises about 500 American species, including 120 species from Brazil. Several authors such as De Candolle, Baker, Heering, Cuatrecasas, Ariza Espinar, Barroso and Giuliano have attempted to elaborate an adequate genus division in subgenera and sections. Baccharis species are economically important since they help to prevent erosion and are employed as ornamental plants, although they can become weeds of difficult control in grazing and poison to the cattle. However, in the folk medicine, many species are relevant and have been studied, aiming to contribute to their morpho-anatomical and quality control knowledge.

Substâncias isoladas das folhas de Bauhinia microstachya (Raddi) Macbr. (Caesalpiniaceae) / Substances isolated from Bauhinia microstachya (Raddi) Macbr. Caesalpiniaceae) leaves

Neste trabalho é relatado o isolamento de três substâncias das folhas de Bauhinia microstachya (Raddi) Macbr., Caesalpiniaceae, incluindo dois constituintes isolados pela primeira vez nesta espécie, a vitexina e o hidrocarboneto hexatriacontano. As estruturas desses compostos foram estabelecidas através de estudos de RMN- 1H 1D, 2D e EM.

It is reported the isolation of three compounds from leaves of Bauhinia microstachya (Raddi) Macbr., Caesalpiniaceae, including two new constituents in this species, vitexin and the hydrocarbon hexatriacontane. Their structures were established by extensive 1D and 2D 1H NMR and MS spectral studies.

Influência de extratos hidroetanólicos de plantas medicinais sobre a quimiotaxia de leucócitos humanos / Influence of some medicinal plant hydroethanolic extracts on human leukocyte chemotaxis

Vários métodos in vitro têm sido empregados para a investigação das atividades biológicas de plantas usadas na medicina popular para o tratamento de processos inflamatórios. Neste trabalho, investigou-se a influência dos extratos hidroetanólicos de Rauvolfia sellowii Muell. Arg, Hybanthus bigibbosus (St.-Hil) Hassler e Anchieta pyrifolia (Mart.) G. Don, conhecidas popularmente como pau-pra-tudo, canela-de-veado e cipó-suma, respectivamente, sobre a quimiotaxia de leucócitos humanos, estimulados a migrar contra um gradiente de caseína, utilizando-se o método de Boyden. A dexametasona foi utilizada como substância de referência da inibição da quimiotaxia leucocitária. Os resultados demonstraram efeito inibitório significativo de todos os extratos das plantas testadas, sobre a migração de polimorfonucleares, induzida por caseína. Entretanto, essa atividade variou de intensidade conforme a concentração e a espécie estudada. Efeitos máximos foram observados, nas concentrações de 1000, 10 e 1µg/ml com os extratos de pau-pra-tudo, canela-de-veado e cipó-suma, respectivamente, com migração de 81,6±3,9 por cento; 85,4±2,4 por cento e 91,7±2,2 por cento dos polimorfonucleares, enquanto que, com a dexametasona, este efeito foi de 70,3±5,9 por cento. Embora estudos mais aprofundados sejam necessários, os resultados apresentados podem servir como base preliminar de dados, contribuindo para esclarecer o mecanismo da atividade antiinflamatória atribuída às essas plantas na medicina caseira.

Several in vitro methods have been used for the investigation of the biological activities of plants used in folk medicine for the treatment of inflammatory conditions. In this study, we have investigated the ability of the hydroethanolic extracts from Rauvolfia sellowii Muell. Arg, Hybanthus bigibbosus (St.-Hil) Hassler, and Anchieta pyrifolia (Mart.) G. Don, locally known as pau-pra-tudo, canela-de-veado, and cipó-suma, respectively, in interfering with the human leukocytes migration induced by casein, using the Boyden chamber method. Dexamethasone has been used as a positive control for leukocyte inhibition in the same experimental approach. The data herein presented showed a significant inhibition of the casein-induced polymorphonuclear leukocytes migration for all plants studied. However, the intensity of such activity was variable according to the dose and plant tested. For pau-pra-tudo, canela-de-veado, and cipó-suma extracts the average number of migrated polymorphonuclear leukocytes was 81.6±3.9 percent, 85.4±2.4 percent and 91.7±2.2 percent of the input for the doses of 1000, 10, and 1mg/ml, respectively, while for dexamethasone, the value found was 70.3±5.9 percent. Although further studies are needed, the results presented in this study may be useful to clarify the anti-inflammatory properties of these herbal medicines, supporting their ethnobothanical use for the treatment of inflammatory diseases.

Parâmetros para análise de carqueja: comparação entre quatro espécies de Baccharis spp. (Asteraceae) / Parameters for carqueja analysis: comparison among four species of Baccharis spp. (Asteraceae)

Diferentes espécies de Baccharis são conhecidas popularmente como carqueja e empregadas indistintamente na medicina tradicional como estomáquicas e diuréticas. O presente trabalho teve como objetivo contribuir para a determinação de parâmetros para o controle de qualidade e aplicação na indústria de fitoterápicos, através da análise de quatro espécies de carqueja: Baccharis dracunculifolia DC., B. articulata (Lam.) Pers., B. cylindrica (Less.) DC. e B. gaudichaudiana DC. De um modo geral, B. dracunculifolia apresentou os maiores teores de umidade e de perda por dessecação, enquanto que B. articulata mostrou os maiores índices afrosimétrico e de amargor e teores de extratos secos a frio e a quente e de cinzas totais. B. dracunculifolia foi a espécie que apresentou maior rendimento do óleo volátil. Alguns componentes do óleo volátil ocorrem nas quatro espécies, porém cada uma delas apresentou um perfil cromatográfico característico.

Different species of Baccharis are commonly known as carqueja and are used indistinctly in the traditional medicine as stomachic and diuretic. This research aimed to carry out the drug analysis of Baccharis dracunculifolia DC., B. articulata (Lam.) Pers., B. cylindrica (Less.) DC. and B. gaudichaudiana DC. In general, B. dracunculifolia showed the highest results of water content, essential oil and loss on drying, while B. articulata showed the highest foam and bitter indices, ash and water soluble extractive results. Some components of the essential oil appeared in the four species, although each one showed a charateristic chromatographic profile by TLC analysis.

Macro and microscopical identification of four species of Baccharis from trimera group

Different species of Baccharis belonging to the Trimera group are commonly named as carqueja and employed for their digestive and diuretic properties. Since the members of this group are alike, this work has aimed to study the macro and microscopical characters of Baccharis articulata, B. cylindrica, B. gaudichaudiana and B. trimera, in order to contribute for the drug analysis and to complement taxonomic knowledge for the Trimera group. These species are shrubs and have three-winged stem, except for B. articulata which possesses two wings. B. gaudichaudiana axis reveals ribs, B. articulata has oval contour and B. cylindrica and B. trimera stem is circular. In B. cylindrica and B. trimera, included phloem has been observed in older basal regions. Calcium oxalate crystals are seen in the four species, being styloid in B. articulata and B. cylindrica and prismatic in B. gaudichaudiana and B. trimera. The other microscopical features observed are similar.

Diferentes espécies de Baccharis pertencentes ao grupo Trimera são comumente denominadas como carqueja e empregadas por suas propriedades digestivas e diuréticas. Como os membros desse grupo são semelhantes, este trabalho objetivou estudar as características macro e microscopicas de Baccharis articulata, B. cylindrica, B. gaudichaudiana e B. trimera, como forma de contribuir à análise das drogas e complementar o conhecimento taxinômico do grupo Trimera. Estas espécies são arbustos e tem caules trialados, com exceção de B. articulata a qual possui duas alas. O axis de B. gaudichaudiana revela nervuras, de B. articulata tem contorno oval e de B. cylindrica e B. trimera stem são circulares. Em B. cylindrica e B. trimera, floema incluso tem sido observado em regiões basais antigas. Cristais de oxalate de calico são vistos nas quarto espécies, do tipo estilóide em B. articulata e B. cylindrica e prismáticos em B. gaudichaudiana e B. trimera. As outras características microscópicas observadas são similares.