A review on phytochemical, ethnomedical and pharmacological studies on genus Sophora, Fabaceae

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Panthati Murali Krishna

2012-04-01

Full Text Available Sophora is a genus of the Fabaceae family, contains about 52 species, nineteen varieties, and seven forms that are widely distributed in Asia, Oceanica, and the Pacific islands, in the family Fabaceae of herbaceous (Sophora flavescens Aiton to trees (Sophora japonica L.. More than fifteen species in this genus have a long history of use in traditional Chinese medicines. In the last decades the use of this genus in traditional Chinese drugs has led to rapid increase in the information available on active components and reported to posses various pharmacological/therapeutic properties. The paper reviews the ethnopharmacology, the biological activities and the correlated chemical compounds of genus Sophora, Fabaceae. More than 300 compounds has been isolated, among them major are quinolizidine alkaloids particularly matrine and oxymatrine and flavonoids particularly prenylated and isoprenylated flavonoids. Modern pharmacological studies and clinical studies demonstrated that these chemical constituens possess wide reaching pharmacological actions like anti oxidant, anticancer, anti-asthamatic, anti-neoplastic, antimicrobial, antiviral, antidote, anti pyretic, cardiotonic, antinflammatory, diuretic and in the treatment of skin diseases like eczema, colitis and psoriasis.

Hypoglycemic Effects of Clitoria ternatea Linn. (Fabaceae) in ...

African Journals Online (AJOL)

Purpose: This study aims to investigate the therapeutic effects of the aqueous extract of Clitoria ternatea Linn. Fabaceae leaves and flowers on alloxan-induced diabetes in rats. Methods: The effect of orally administered aqueous extracts (400 mg/kg body weight) of Clitoria ternatea leaves and flowers on serum glucose, ...

New chromosome numbers in the genus Trigonella L. ( Fabaceae ...

African Journals Online (AJOL)

Somatic chromosome numbers of 45 Trigonella L. (Fabaceae), collected from different localities in Turkey was examined. Chromosome numbers were determined as 2n = 14, 16, 30 and 46. B chromosome was also observed in somatic cells of some taxa (Trigonella arcuata C.A. Meyer and Trigonella procumbens (Besser) ...

Determination of a-glucosidase inhibitory activity from selected Fabaceae plants.

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Dej-Adisai, Sukanya; Pitakbut, Thanet

2015-09-01

Nineteen plants from Fabaceae family, which were used in Thai traditional medicine for treatment of diabetes, were determined of α-glucosidase inhibitory activity via enzymatic reaction. In this reaction, α-glucosidase was used as enzyme, which, reacted with the substrate, p-nitrophenol-D-glucopyranoside (pNPG). After that the product, p-nitro phenol (pNP) will be occurred and observed the yellow colour at 405 nm. In this study, acarbose was used as positive standard which, inhibited this enzyme with IC₅₀ as 331 ± 4.73 μg/ml. Caesalpinia pulcherrima leaves showed the highest activity with IC₅₀ as 436.97 ± 9.44 μg/ml. Furthermore, Bauhinia malabarica leaves presented moderately activity with IC₅₀ as 745.08 ± 11.15 μg/ml. However, the other plants showed mild to none activity of α-glucosidase inhibition. Accordingly, this study can support anti-diabetes of these plants in traditional medicine and it will be the database of the biological activity of Fabaceae plant.

Biflavonoids and other phenolics from Caesalpinia pyramidalis (Fabaceae)

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Bahia, Marcus V.; Santos, Jamile B. dos; David, Juceni P.; David, Jorge M.

2005-01-01

The chloroform extract of the leaves of Caesalpinia pyramidalis (Caesalpinioidea, Fabaceae) yielded the new biflavonoid named caesalflavone, as well as podocarpusflavone A, agathisflavone, apigenin and kaempferol. The chloroform extract of the trunk wood gave 4,4'-dihydroxy-2'-methoxychalcone, (-)-syringaresinol, and methyl gallate. Biflavonoids were not found in trunk wood. Until now, C. pyramidalis is the first species in the genus to present biflavonoids. The structural elucidation of the ...

The complete chloroplast genomes of two Wisteria species, W. floribunda and W. sinensis (Fabaceae).

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Kim, Na-Rae; Kim, Kyunghee; Lee, Sang-Choon; Lee, Jung-Hoon; Cho, Seong-Hyun; Yu, Yeisoo; Kim, Young-Dong; Yang, Tae-Jin

2016-11-01

Wisteria floribunda and Wisteria sinensis are ornamental woody vines in the Fabaceae. The complete chloroplast genome sequences of the two species were generated by de novo assembly using whole genome next generation sequences. The chloroplast genomes of W. floribunda and W. sinensis were 130 960 bp and 130 561 bp long, respectively, and showed inverted repeat (IR)-lacking structures as those reported in IRLC in the Fabaceae. The chloroplast genomes of both species contained same number of protein-coding sequences (77), tRNA genes (30), and rRNA genes (4). The phylogenetic analysis with the reported chloroplast genomes confirmed close taxonomical relationship of W. floribunda and W. sinensis.

Bioacoustics of Acanthoscelides obtectus (Coleoptera: Chrysomelidae: Bruchinae) on Phaseolus vulgaris (Fabaceae)

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Acanthoscelides obtectus (Say) (Coleoptera: Chrysomelidae), is an economically important pest of common bean Phaseolus vulgaris L. (Fabaceae) in the tropics and subtropics. It is difficult to detect the presence of A. obtectus because the larvae are cryptic and spend most of their developmental time...

Plant antiherbivore defenses in Fabaceae species of the Chaco.

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Lima, T E; Sartori, A L B; Rodrigues, M L M

2017-01-01

The establishment and maintenance of plant species in the Chaco, one of the widest continuous areas of forests in the South American with sharp climatic variations, are possibly related to biological features favoring plants with particular defenses. This study assesses the physical and chemical defenses mechanisms against herbivores of vegetative and reproductive organs. Its analyses of 12 species of Fabaceae (Leguminosae) collected in remnants of Brazilian Chaco shows that 75% present structural defense characters and 50% have chemical defense - defense proteins in their seeds, like protease inhibitors and lectins. Physical defenses occur mainly on branches (78% of the species), leaves (67%), and reproductive organs (56%). The most common physical characters are trichomes and thorns, whose color represents a cryptic character since it does not contrast with the other plant structures. Defense proteins occur in different concentrations and molecular weight classes in the seeds of most species. Protease inhibitors are reported for the first time in seeds of: Albizia niopoides, Anadenanthera colubrina, Mimosa glutinosa, Prosopis rubriflora, and Poincianella pluviosa. The occurrence of physical and chemical defenses in members of Fabaceae indicate no associations between defense characters in these plant species of the Chaco.

Checklist of Fabaceae Lindley in Balaghat Ranges of Maharashtra, India

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Ramchandra Gore

2015-03-01

Full Text Available The present paper provides an enumeration of leguminous taxa of Balaghat Ranges of Maharashtra along with their habits, phenological deta and voucher specimen numbers. During the present work, a total of 123 species, 4 subspecies and 17 varieties of Fabaceae have been recorded for Balaghat Ranges of Maharashtra, of which 119 taxa are occurring in wild while 25 are under cultivation. The members of Fabaceae are dominant in herbaceous vegetation of the Balaghat Ranges. There are more species in genera like Crotalaria (23 taxa, Indigofera (16 taxa, Alysicarpus (14 taxa, Vigna (11 taxa and Desmodium (8 taxa. Twelve taxa are endemic to India of which Indigofera deccanensis falls into Critically Endangered IUCN Red data category. The legumes of Balaghat Ranges have many actual and potential uses such as food, fodder and sources of edible oil, natural dyes, industrial lubricants, timber and medicines. About 19 leguminous taxa are wild relatives of food and fodder crops have resistance to pests and diseases, and abiotic stresses such as drought and salinity, can be used for crop improvement.

Biflavonoids and other phenolics from Caesalpinia pyramidalis (Fabaceae)

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Bahia, Marcus Vinicius; Santos, Jamile Batista dos; David, Juceni Pereira de Lima; David, Jorge Mauricio

2005-01-01

p. 1402-1405 O reestudo do extrato clorofórmico das folhas de Caesalpinia pyramidalis (Caesalpinioidea, Fabaceae) forneceu, além do novo biflavonóide denominado caesalflavona, podocarpusflavona A, agathisflavona, apigenina, kaempferol, sitosterol e lupeol. Por outro lado, a partir do extrato clorofórmico do caule foram obtidos 4, 4'-diidroxi-2'-metoxi-chalcona, (-)-siringaresinol e galato de metila. Não foram encontrados biflavonóides nesta parte da planta. Até o presente, C. pyramidalis é...

No evidence for Fabaceae Gametophytic self-incompatibility being determined by Rosaceae, Solanaceae, and Plantaginaceae S-RNase lineage genes.

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Aguiar, Bruno; Vieira, Jorge; Cunha, Ana E; Vieira, Cristina P

2015-06-02

Fabaceae species are important in agronomy and livestock nourishment. They have a long breeding history, and most cultivars have lost self-incompatibility (SI), a genetic barrier to self-fertilization. Nevertheless, to improve legume crop breeding, crosses with wild SI relatives of the cultivated varieties are often performed. Therefore, it is fundamental to characterize Fabaceae SI system(s). We address the hypothesis of Fabaceae gametophytic (G)SI being RNase based, by recruiting the same S-RNase lineage gene of Rosaceae, Solanaceae or Plantaginaceae SI species. We first identify SSK1 like genes (described only in species having RNase based GSI), in the Trifolium pratense, Medicago truncatula, Cicer arietinum, Glycine max, and Lupinus angustifolius genomes. Then, we characterize the S-lineage T2-RNase genes in these genomes. In T. pratense, M. truncatula, and C. arietinum we identify S-RNase lineage genes that in phylogenetic analyses cluster with Pyrinae S-RNases. In M. truncatula and C. arietinum genomes, where large scaffolds are available, these sequences are surrounded by F-box genes that in phylogenetic analyses also cluster with S-pollen genes. In T. pratense the S-RNase lineage genes show, however, expression in tissues not involved in GSI. Moreover, levels of diversity are lower than those observed for other S-RNase genes. The M. truncatula and C. arietinum S-RNase and S-pollen like genes phylogenetically related to Pyrinae S-genes, are also expressed in tissues other than those involved in GSI. To address if other T2-RNases could be determining Fabaceae GSI, here we obtained a style with stigma transcriptome of Cytisus striatus, a species that shows significant difference on the percentage of pollen growth in self and cross-pollinations. Expression and polymorphism analyses of the C. striatus S-RNase like genes revealed that none of these genes, is the S-pistil gene. We find no evidence for Fabaceae GSI being determined by Rosaceae, Solanaceae, and

Molecular systematics of selected genera of subfamily mimosoidae-fabaceae

International Nuclear Information System (INIS)

Shinwari, Z.K.; Jamil, K.; Zahra, N.B.

2014-01-01

Family Mimosoidae-Fabaceae is of economic importance to local communities for its medicinal usage. It has commercial value, but the parts sold in the market are difficult to identify on the basis of morphological characters and therefore needs molecular systematics approaches. Hence, the utility of potential DNA barcodes for selected Acacia and Albizia species by using three cpDNA regions rbcL, matK and trnH-psbA was tested in this study. Our study suggests that the rbcL region can be used to identify these species and discriminate among them more effectively than matK and trnH-psbA. The latter regions proved to be less successful in sequencing particularly trnH-psbA. Therefore, rbcL is an improved and efficient tool for species identification of these medicinal plants and may be recommended for a broad series of subfamily Mimosoideae (Family: Fabaceae) plants, making it a potential DNA barcode for these taxa. Sequence data obtained from rbcL and matK also indicated that Acacia and Albizia are polyphyletic. The phylogenetic analysis on the basis of rbcL proved that Acacia nilotica and Acacia nilotica ssp. hemispherica are closely related as they form the sister groups. (author)

The Usefulness of Edible and Medicinal Fabaceae in Argentine and Chilean Patagonia: Environmental Availability and Other Sources of Supply

OpenAIRE

Molares, Soledad; Ladio, Ana

2011-01-01

Fabaceae is of great ethnobotanical importance in indigenous and urban communities throughout the world. This work presents a revision of the use of Fabaceae as a food and/or medicinal resource in Argentine-Chilean Patagonia. It is based on a bibliographical analysis of 27 ethnobotanical sources and catalogues of regional flora. Approximately 234 wild species grow in Patagonia, mainly (60%) in arid environments, whilst the remainder belong to Sub-Antarctic forest. It was found that 12.8% (30 ...

A New Aggreceride analogue and a peltogynoid isolated from the stem bark of Entada abyssinica (Fabaceae).

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Melong, Raduis; Kapche, Deccaux G F W; Feussia, Michel T; Laatsch, Hartmut

2014-10-01

A new monoglyceride, l',26'-bis-[(S)-2,3-dihydroxypropyl] hexacosanedioate (1a) and the new peltogynoid, entadanin (3), along with eight known compounds, were isolated from the stem bark of Entada abyssinica (Fabaceae). The structures of the new compounds were determined by detailed analyses of 1D and 2D NMR spectra, in combination with high-resolution mass spectrometry data, and by comparison with related data from the literature. The stereochemistry of la was derived by comparison of the optical rotation with reference data. Peltogynoids have been reported previously from other Fabaceae, however this is the first report ofa peltogynoid from the genus Entada.

Biflavonoids and other phenolics from Caesalpinia pyramidalis (Fabaceae)

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Bahia, Marcus V.; Santos, Jamile B. dos; David, Jorge M. [Bahia Univ., Salvador, BA (Brazil). Inst. de Quimica; David, Juceni P. [Bahia Univ., Salvador, BA (Brazil). Faculdade de Farmacia

2005-11-15

The chloroform extract of the leaves of Caesalpinia pyramidalis (Caesalpinioidea, Fabaceae) yielded the new biflavonoid named caesalflavone, as well as podocarpusflavone A, agathisflavone, apigenin and kaempferol. The chloroform extract of the trunk wood gave 4,4'-dihydroxy-2'-methoxychalcone, (-)-syringaresinol, and methyl gallate. Biflavonoids were not found in trunk wood. Until now, C. pyramidalis is the first species in the genus to present biflavonoids. The structural elucidation of the isolated compounds and their derivatives were based on MS, IR, UV, 1D and 2D NMR spectral analyses. (au)

Biflavonoids and other phenolics from Caesalpinia pyramidalis (Fabaceae)

International Nuclear Information System (INIS)

Bahia, Marcus V.; Santos, Jamile B. dos; David, Jorge M.; David, Juceni P.

2005-01-01

The chloroform extract of the leaves of Caesalpinia pyramidalis (Caesalpinioidea, Fabaceae) yielded the new biflavonoid named caesalflavone, as well as podocarpusflavone A, agathisflavone, apigenin and kaempferol. The chloroform extract of the trunk wood gave 4,4'-dihydroxy-2'-methoxychalcone, (-)-syringaresinol, and methyl gallate. Biflavonoids were not found in trunk wood. Until now, C. pyramidalis is the first species in the genus to present biflavonoids. The structural elucidation of the isolated compounds and their derivatives were based on MS, IR, UV, 1D and 2D NMR spectral analyses. (author)

A taxonomic revision of the genus Rafnia Thunb. (Fabaceae, Crotalarieae)

OpenAIRE

2012-01-01

M.Sc. A taxonomic revision of the genus Rafnia Thunb. (= Oedmannia Thunb., Vascoa DC., Pelecynthis E. Mey), a relatively poorly known papilionoid legume genus, is presented. Rafnia (family Fabaceae, tribe Crotalarieae) is subendemic to the fynbos region of the Western and Eastern Cape Provinces of South Africa, with one species having a distribution area reaching into KwaZulu-Natal. The species delimitation has been unsatisfactory, and the relationships among the taxa uncertain. Rafnia is ...

Chemical constituents from Piptadenia rigida Benth., Fabaceae, "angico"

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Mário G. de Carvalho

2011-06-01

Full Text Available The phytochemical investigation of the roots of Piptadenia rigida Benth., Fabaceae, known as "angico", afforded sitosterol, lupeol, betuline, the chalcone isoliquiritigenin, the flavonoids, 7,4'-dihydroxyflavone, 7,3',4'-trihydroxyflavone, 7,8,3',4'-tetrahydroxyflavanone, 4-hydroxy-3,5-dimethoxybenzaldehyde and methyl-3,4-dihydroxy-benzoate. Both flavones were also isolated from the branches of this plant. Five derivatives of the aldehyde were obtained by diazomethane treatment. The structures of compounds were identified by IR, NMR and mass spectral data analysis of natural compounds and some derivatives, and by comparison with literature data.

Chemical constituents from Piptadenia rigida Benth., Fabaceae, "angico"

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Mário G. de Carvalho

2010-03-01

Full Text Available The phytochemical investigation of the roots of Piptadenia rigida Benth., Fabaceae, known as "angico", afforded sitosterol, lupeol, betuline, the chalcone isoliquiritigenin, the flavonoids, 7,4'-dihydroxyflavone, 7,3',4'-trihydroxyflavone, 7,8,3',4'-tetrahydroxyflavanone, 4-hydroxy-3,5-dimethoxybenzaldehyde and methyl-3,4-dihydroxy-benzoate. Both flavones were also isolated from the branches of this plant. Five derivatives of the aldehyde were obtained by diazomethane treatment. The structures of compounds were identified by IR, NMR and mass spectral data analysis of natural compounds and some derivatives, and by comparison with literature data.

Chemical constituents from Astragalus annularis Forssk. and A. trimestris L., Fabaceae

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Amr M. El-Hawiet

2010-11-01

Full Text Available The phytochemical investigation of the aerial parts of Astragalus annularis Forssk. and A. trimestris L., Fabaceae, growing in Egypt, resulted in the isolation of eight compounds, for the first time from these two species. These compounds were identified by chemical methods, NMR spectroscopy, UV spectroscopy as well as MS analysis. The antimicrobial activity of the isolated compounds were tested against Staphylococcus aureus, Esherichia coli and Candida albicans.

Identification of medicinal plants in the family Fabaceae using a potential DNA barcode ITS2.

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Gao, Ting; Yao, Hui; Song, Jingyuan; Liu, Chang; Zhu, Yingjie; Ma, Xinye; Pang, Xiaohui; Xu, Hongxi; Chen, Shilin

2010-07-06

To test whether the ITS2 region is an effective marker for use in authenticating of the family Fabaceae which contains many important medicinal plants. The ITS2 regions of 114 samples in Fabaceae were amplified. Sequence assembly was assembled by CodonCode Aligner V3.0. In combination with sequences from public database, the sequences were aligned by Clustal W, and genetic distances were computed using MEGA V4.0. The intra- vs. inter-specific variations were assessed by six metrics, wilcoxon two-sample tests and "barcoding gaps". Species identification was accomplished using TaxonGAP V2.4, BLAST1 and the nearest distance method. ITS2 sequences had considerable variation at the genus and species level. The intra-specific divergence ranged from 0% to 14.4%, with an average of 1.7%, and the inter-specific divergence ranged from 0% to 63.0%, with an average of 8.6%. Twenty-four species found in the Chinese Pharmacopoeia, along with another 66 species including their adulterants, were successfully identified based on ITS2 sequences. In addition, ITS2 worked well, with over 80.0% of species and 100% of genera being correctly differentiated for the 1507 sequences derived from 1126 species belonging to 196 genera. Our findings support the notion that ITS2 can be used as an efficient and powerful marker and a potential barcode to distinguish various species in Fabaceae. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Is induction ability of seed germination of Phelipanche ramosa phylogenetically structured among hosts? A case study on Fabaceae species.

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Perronne, Rémi; Gibot-Leclerc, Stéphanie; Dessaint, Fabrice; Reibel, Carole; Le Corre, Valérie

2017-12-01

Phelipanche ramosa is a major root-holoparasitic damaging weed characterized by a broad host range, including numerous Fabaceae species. In France, the agricultural threat posed by P. ramosa has increased over two decades due to the appearance of a genetically differentiated pathovar presenting a clear host specificity for oilseed rape. The new pathovar has led to a massive expansion of P. ramosa in oilseed rape fields. The germination rate of P. ramosa seeds is currently known to vary among P. ramosa pathovars and host species. However, only a few studies have investigated whether phylogenetic relatedness among potential host species is a predictor of the ability of these species to induce the seed germination of parasitic weeds by testing for phylogenetic signal. We focused on a set of 12 Fabaceae species and we assessed the rate of induction of seed germination by these species for two pathovars based on in vitro co-cultivation experiments. All Fabaceae species tested induced the germination of P. ramosa seeds. The germination rate of P. ramosa seeds varied between Fabaceae species and tribes studied, while pathovars appeared non-influential. Considering oilseed rape as a reference species, we also highlighted a significant phylogenetic signal. Phylogenetically related species therefore showed more similar rates of induction of seed germination than species drawn at random from a phylogenetic tree. In in vitro conditions, only Lotus corniculatus induced a significantly higher germination rate than oilseed rape, and could potentially be used as a catch crop after confirmation of these results under field conditions.

Assessing universality of DNA barcoding in geographically isolated selected desert medicinal species of Fabaceae and Poaceae

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Hussain, Fatma; Ahmed, Nisar; Ghorbani, Abdolbaset

2018-01-01

In pursuit of developing fast and accurate species-level molecular identification methods, we tested six DNA barcodes, namely ITS2, matK, rbcLa, ITS2+matK, ITS2+rbcLa, matK+rbcLa and ITS2+matK+rbcLa, for their capacity to identify frequently consumed but geographically isolated medicinal species of Fabaceae and Poaceae indigenous to the desert of Cholistan. Data were analysed by BLASTn sequence similarity, pairwise sequence divergence in TAXONDNA, and phylogenetic (neighbour-joining and maximum-likelihood trees) methods. Comparison of six barcode regions showed that ITS2 has the highest number of variable sites (209/360) for tested Fabaceae and (106/365) Poaceae species, the highest species-level identification (40%) in BLASTn procedure, distinct DNA barcoding gap, 100% correct species identification in BM and BCM functions of TAXONDNA, and clear cladding pattern with high nodal support in phylogenetic trees in both families. ITS2+matK+rbcLa followed ITS2 in its species-level identification capacity. The study was concluded with advocating the DNA barcoding as an effective tool for species identification and ITS2 as the best barcode region in identifying medicinal species of Fabaceae and Poaceae. Current research has practical implementation potential in the fields of pharmaco-vigilance, trade of medicinal plants and biodiversity conservation. PMID:29576968

Vicia vulcanorum (Fabaceae a new species from the island of Lanzarote (Canary Islands

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Morales-Mateos, J. B.

2012-12-01

Full Text Available Vicia vulcanorum J. Gil & M. L. Gil (Fabaceae, a new species of subg. Cracca (Dumort. Peterm., sect. Cracca Dumort. is described and illustrated from the island of Lanzarote, Canary Islands, north-west of Africa. It is related to and compared with Vicia cirrhosa C. Sm. ex Webb & Berthel. and Vicia filicaulis Webb & Berthel., two endemic species from the western and central group of the Canary Islands, and Vicia ferreirensis Goyder, an endemic species from Porto Santo Island, Madeira Archipelago.Se describe e ilustra Vicia vulcanorum J. Gil & M. L. Gil (Fabaceae, una nueva especie y endemismo de la isla de Lanzarote, Islas Canarias, perteneciente al subg. Cracca (Dumort. Peterm., sect. Cracca Dumort. Se encuentra relacionada y es comparada con Vicia cirrhosa C. Sm. ex Webb & Berthel. y Vicia filicaulis Webb & Berthel., especies endémicas de las islas centrales y occidentales del archipiélago canario, y con Vicia ferreirensis Goyder, especie endémica de la isla de Porto Santo, en el archipiélago de Madeira.

New Records of Bruchidius Spermaphagous Species in Albizia julibrissin and Laburnum anagyroides and Their Parasitoid Complex in Serbia

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Renata Gagić Serdar

2014-12-01

Full Text Available Background and Purpose: Bruchidius villosus feeding in seed of Laburnum anagyroides, and Bruchidius terrenus seed pest of Albizia julibrissin are first recorded and completely new seed-beetle to Serbian Bruchinae fauna. This Chrysomelids which were found in Republic of Serbia during intensive studies from 2012 to 2014 are likely related to a mostly Paleotropical group, including also members of genera Bruchidius, Megabruchidius and Acanthoscellides. These seed-beetles develop in pods of these two woody legumes, widely grown ornamental trees and shrubs. Several recent reports reveal that this species are well established in France, Hungary, and Bulgaria. Materials and Methods: Bruchine and their legume hosts were observed by extensive field sampling throughout Serbia over three years and by rearing the beetles from the samples in the laboratory. Bruchines and the parasitoids were mass-reared in climate controled rooms under conditions close to those of their area of origin: 12:12 L:D, 3-23 °C and ≤80 % RH (depends of host plant ongoing phenology or experimental needs-proof of weevil monophagous feeding preferences. For the purpose of analyzing the observed phenomena (its intensity and relevance, some of the standard methods of statistical analysis and conclusion have been used. Results: Levels of seeds infestation still in the pods were high and comparable to other studies. Bruchine beetle infestation in the dehiscent fruits of host plants may be greater after the seeds and pods drop to the ground, as bivoltine generation occurs, but this has yet to be tested. Hypotheses on the geographic origin of this new species are also discussed. The effect of native parasitoids occurrence could potentially be interesting, given that their appearance suggest their specialization on the Bruchidius beetle species which is a common seed-predator on the leguminous seeds. Conclusions: The establishment of this new species is investigated using both

Breeding biology of the threadstalk milkvetch, Astragalus filipes (Fabaceae), with a review of the genus

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Astragalus L. (Fabaceae) is an enormous and diverse plant genus with a cosmopolitan distribution, but relatively few breeding biologies are known for its member species. Threadstalk (or basalt) milkvetch, Astragalus filipes Torrey ex. A. Gray, is common and widespread throughout the US Intermountai...

The genus Machaerium (Fabaceae): taxonomy, phytochemistry, traditional uses and biological activities.

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Amen, Yhiya M; Marzouk, Amani M; Zaghloul, Mona G; Afifi, Mohamed S

2015-01-01

Machaerium, in the family Fabaceae, predominantly is a genus of a Neotropical distribution of trees, shrubs, and lianas occurring from southern Mexico to Brazil and northern Argentina and as far as South America. Several Machaerium species are widely used in traditional medicine and are considered to have multiple medicinal properties. This review aims to provide up-to-date and comprehensive information on the taxonomy, phytochemistry, traditional uses and biological activities of plants in the genus Machaerium.

Review of the Eriococcidae (Hemiptera: Coccomorpha) infesting Fabaceae in Argentina, with descriptions of three new species of Acanthococcus Signoret.

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González, Patricia; Claps, Lucía E; Juárez, Andrea; Moreno, Diego

2017-02-15

Three new species of Eriococcidae from Argentina, namely Acanthococcus haywardi Juárez & González sp. nov., A. punctatae Juárez & González sp. nov. and A. riojensis Juárez & González sp. nov., are described and illustrated, bringing the total number of eriococcid species now known from Argentina to 12, of which six belong to Acanthococcus Signoret and six to Hempelicoccus Kozár. They are found on 11 species of Fabaceae (subfamilies Mimosoideae and Caesalpinioidae), are widely distributed and are all restricted to the Neotropical region and the South American Transitional Zone. A key to the 12 Eriococcidae species now known on Fabaceae in Argentina is included.

The Usefulness of Edible and Medicinal Fabaceae in Argentine and Chilean Patagonia: Environmental Availability and Other Sources of Supply

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Soledad Molares

2012-01-01

Full Text Available Fabaceae is of great ethnobotanical importance in indigenous and urban communities throughout the world. This work presents a revision of the use of Fabaceae as a food and/or medicinal resource in Argentine-Chilean Patagonia. It is based on a bibliographical analysis of 27 ethnobotanical sources and catalogues of regional flora. Approximately 234 wild species grow in Patagonia, mainly (60% in arid environments, whilst the remainder belong to Sub-Antarctic forest. It was found that 12.8% (30 species, mainly woody, conspicuous plants, are collected for food or medicines. Most of the species used grow in arid environments. Cultivation and purchase/barter enrich the Fabaceae offer, bringing it up to a total of 63 species. The richness of native and exotic species, and the existence of multiple strategies for obtaining these plants, indicates hybridization of knowledge and practices. Only 22% of the total species used are mentioned in bothcontexts of food and medicine, reflecting low-use complementation. This study suggests a significant ecological appearance and a high level of availability in shops and exchange networks in Patagonia, highlighting the need to consider the full set of environmental and socioeconomic factors in research related to the use and cultural importance of plants in regional contexts.

The Usefulness of Edible and Medicinal Fabaceae in Argentine and Chilean Patagonia: Environmental Availability and Other Sources of Supply

Science.gov (United States)

Molares, Soledad; Ladio, Ana

2012-01-01

Fabaceae is of great ethnobotanical importance in indigenous and urban communities throughout the world. This work presents a revision of the use of Fabaceae as a food and/or medicinal resource in Argentine-Chilean Patagonia. It is based on a bibliographical analysis of 27 ethnobotanical sources and catalogues of regional flora. Approximately 234 wild species grow in Patagonia, mainly (60%) in arid environments, whilst the remainder belong to Sub-Antarctic forest. It was found that 12.8% (30 species), mainly woody, conspicuous plants, are collected for food or medicines. Most of the species used grow in arid environments. Cultivation and purchase/barter enrich the Fabaceae offer, bringing it up to a total of 63 species. The richness of native and exotic species, and the existence of multiple strategies for obtaining these plants, indicates hybridization of knowledge and practices. Only 22% of the total species used are mentioned in bothcontexts of food and medicine, reflecting low-use complementation. This study suggests a significant ecological appearance and a high level of availability in shops and exchange networks in Patagonia, highlighting the need to consider the full set of environmental and socioeconomic factors in research related to the use and cultural importance of plants in regional contexts. PMID:22194774

First record of Acizzia jamatonica (Hemiptera: Psyllidae) in North America: friend or foe?

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Michael D. Ulyshen; Douglass Miller

2007-01-01

Acizzia jamatonica (Kuwayama) (Hemiptera: Sternorrhyncha: Psyllidae) is reported for the first time in North America. Because the species is thought to feed exclusively on Albizia, it may prove to be an effective biocontrol agent against the invasive Albizia julibrissin Durazzini in the southeastern United States. Because A. julibrissin is also an ornamental plant of...

Antioxidant activity of nine Fabaceae species growing in Serbia and Montenegro.

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Godevac, Dejan; Zdunić, Gordana; Savikin, Katarina; Vajs, Vlatka; Menković, Nebojsa

2008-04-01

The aim of this study was to investigate antioxidant capacity of nine Fabaceae species collected on the mountains of Serbia and Montenegro. Antioxidant assays with various reaction mechanisms were used, including total phenolic content by Folin-Ciocalteu, DPPH radical scavenging capacity, Trolox equivalent antioxidant capacity (TEAC) values by ABTS radical cation and inhibition of liposome peroxidation. The investigated plants exhibited strong antioxidant capacity in all the tested methods, and among them, Lathyrus binatus, Trifolium pannonicum, and Anthyllis aurea were found to be the most active.

Biological activity and LC-MS/MS profiling of extracts from the Australian medicinal plant Acacia ligulata (Fabaceae)

DEFF Research Database (Denmark)

Knudsen, Diana Jæger; Simpson, Bradley S.; Ndi, Chi P.

2018-01-01

Acacia ligulata A.Cunn. ex Benth. (Fabaceae: Mimosoideae) is a native Australian plant used traditionally by Australian Aboriginal groups. This study was undertaken to investigate the bioactivity of A. ligulata extracts and to evaluate their chemical composition. Potential antibacterial, cytotoxic...

Breeding biology of the threadstalk milkvetch, Astragalus filipes (Fabaceae), with a review of the genus

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Kristal M. Watrous; James H. Cane

2011-01-01

Astragalus L. (Fabaceae) is an enormous and diverse plant genus with a cosmopolitan distribution, but relatively few breeding biologies are known for its member species. Threadstalk (or basalt) milkvetch, Astragalus filipes Torrey ex. A. Gray, is common and widespread throughout the U.S. Intermountain West, including the Great Basin. It is being studied and ultimately...

Metabolite fingerprinting, pathway analyses, and bioactivity correlations for plant species belonging to the Cornaceae, Fabaceae, and Rosaceae families.

Science.gov (United States)

Son, Su Young; Kim, Na Kyung; Lee, Sunmin; Singh, Digar; Kim, Ga Ryun; Lee, Jong Seok; Yang, Hee-Sun; Yeo, Joohong; Lee, Sarah; Lee, Choong Hwan

2016-09-01

A multi-parallel approach gauging the mass spectrometry-based metabolite fingerprinting coupled with bioactivity and pathway evaluations could serve as an efficacious tool for inferring plant taxonomic orders. Thirty-four species from three plant families, namely Cornaceae (7), Fabaceae (9), and Rosaceae (18) were subjected to metabolite profiling using gas chromatography-time-of-flight-mass spectrometry (GC-TOF-MS) and ultrahigh performance liquid chromatography-linear trap quadrupole-ion trap-mass spectrometry (UHPLC-LTQ-IT-MS/MS), followed by multivariate analyses to determine the metabolites characteristic of these families. The partial least squares discriminant analysis (PLS-DA) revealed the distinct clustering pattern of metabolites for each family. The pathway analysis further highlighted the relatively higher proportions of flavonols and ellagitannins in the Cornaceae family than in the other two families. Higher levels of phenolic acids and flavan-3-ols were observed among species from the Rosaceae family, while amino acids, flavones, and isoflavones were more abundant among the Fabaceae family members. The antioxidant activities of plant extracts were measured using ABTS, DPPH, and FRAP assays, and indicated that extracts from the Rosaceae family had the highest activity, followed by those from Cornaceae and Fabaceae. The correlation map analysis positively links the proportional concentration of metabolites with their relative antioxidant activities, particularly in Cornaceae and Rosaceae. This work highlights the pre-eminence of the multi-parallel approach involving metabolite profiling and bioactivity evaluations coupled with metabolic pathways as an efficient methodology for the evaluation of plant phylogenies.

SUKU FABACEAE DI KAMPUS UNIVERSITAS ISLAM NEGERI SYARIF HIDAYATULLAH, JAKARTA, BAGIAN 2: TUMBUHAN POLONG BERPERAWAKAN TERNA

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Priyanti Priyanti

2017-04-01

Full Text Available Abstrak Suku Fabaceae adalah tetumbuhan yang memiliki buah bertipe polong. Suku tersebut selain berperawakan pohon juga berupa terna. Anggota suku Fabaceae (polong banyak ditemukan di sekitar lingkungan manusia termasuk di Kampus Universitas Islam Negeri (UIN Syarif Hidayatullah, Jakarta. Informasi mengenai keanekaragaman tumbuhan polong yang berupa terna di Kampus UIN Syarif Hidayatullah belum tersedia. Penelitian dilakukan menggunakan metode jelajah di kampus I dan II serta studi pustaka. Sebanyak 3 jenis tumbuhan polong berperawakan terna telah didapatkan di lingkungan kampus, yaitu Arachis pintoi Krapov. & W. C. Greg., Mimosa diplotricha C. Wright ex Sauvalle, dan M. pudica L. Jenis-jenis tersebut termasuk ke dalam 2 anak suku (Faboideae, Mimosoideae dan 2 puak (Aeschynomeneae, Mimoseae. Jenis-jenis tersebut tumbuh di lokasi yang berbeda-beda. Tumbuhan polong yang hanya ditemukan di Fakultas Kedokteran dan Ilmu Keshatan (FKIK adalah A. pintoi. Mimosa diplotricha ditemukan tumbuh di Pusat Laboratorium Terpadu Fakultas Sains dan Teknologi, Perpustakaan Utama, FKIK, Fakultas Sosial dan Ilmu Politik (FISIP, Wisma Syahida, Pusat Bahasa, dan Sekolah Pascasarjana, sedangkan M. pudica ditemukan Perpustakaan Utama, FISIP, dan Wisma Syahida. Kelengkapan data tentang tumbuhan polong di Kampus UIN Syarif Hidayatullah ini dapat digunakan oleh para mahasiswa untuk mempelajari keanekaragamnnya. Abstract Fabaceae is a plant with a pod-type fruit. A Habit of this family is not only trees but also herb. Fabaceae (legumes is often found on the human environment around campus included in the State Islamic University (UIN Syarif Hidayatullah, Jakarta. The Information about the legume herbs diversity on the UIN Syarif Hidayatullah yet available. The study was conducted using survey and literature methods. There were 3 species legume herbs in the campus, viz. Arachis pintoi Krapov. & W. C. Greg., Mimosa diplotricha C. Wright ex Sauvalle, and M. pudica L. All

Seed storage protein gene promoters contain conserved DNA motifs in Brassicaceae, Fabaceae and Poaceae

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Fauteux, François; Strömvik, Martina V

2009-01-01

Background Accurate computational identification of cis-regulatory motifs is difficult, particularly in eukaryotic promoters, which typically contain multiple short and degenerate DNA sequences bound by several interacting factors. Enrichment in combinations of rare motifs in the promoter sequence of functionally or evolutionarily related genes among several species is an indicator of conserved transcriptional regulatory mechanisms. This provides a basis for the computational identification of cis-regulatory motifs. Results We have used a discriminative seeding DNA motif discovery algorithm for an in-depth analysis of 54 seed storage protein (SSP) gene promoters from three plant families, namely Brassicaceae (mustards), Fabaceae (legumes) and Poaceae (grasses) using backgrounds based on complete sets of promoters from a representative species in each family, namely Arabidopsis (Arabidopsis thaliana (L.) Heynh.), soybean (Glycine max (L.) Merr.) and rice (Oryza sativa L.) respectively. We have identified three conserved motifs (two RY-like and one ACGT-like) in Brassicaceae and Fabaceae SSP gene promoters that are similar to experimentally characterized seed-specific cis-regulatory elements. Fabaceae SSP gene promoter sequences are also enriched in a novel, seed-specific E2Fb-like motif. Conserved motifs identified in Poaceae SSP gene promoters include a GCN4-like motif, two prolamin-box-like motifs and an Skn-1-like motif. Evidence of the presence of a variant of the TATA-box is found in the SSP gene promoters from the three plant families. Motifs discovered in SSP gene promoters were used to score whole-genome sets of promoters from Arabidopsis, soybean and rice. The highest-scoring promoters are associated with genes coding for different subunits or precursors of seed storage proteins. Conclusion Seed storage protein gene promoter motifs are conserved in diverse species, and different plant families are characterized by a distinct combination of conserved motifs

Seed storage protein gene promoters contain conserved DNA motifs in Brassicaceae, Fabaceae and Poaceae

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Fauteux François

2009-10-01

Full Text Available Abstract Background Accurate computational identification of cis-regulatory motifs is difficult, particularly in eukaryotic promoters, which typically contain multiple short and degenerate DNA sequences bound by several interacting factors. Enrichment in combinations of rare motifs in the promoter sequence of functionally or evolutionarily related genes among several species is an indicator of conserved transcriptional regulatory mechanisms. This provides a basis for the computational identification of cis-regulatory motifs. Results We have used a discriminative seeding DNA motif discovery algorithm for an in-depth analysis of 54 seed storage protein (SSP gene promoters from three plant families, namely Brassicaceae (mustards, Fabaceae (legumes and Poaceae (grasses using backgrounds based on complete sets of promoters from a representative species in each family, namely Arabidopsis (Arabidopsis thaliana (L. Heynh., soybean (Glycine max (L. Merr. and rice (Oryza sativa L. respectively. We have identified three conserved motifs (two RY-like and one ACGT-like in Brassicaceae and Fabaceae SSP gene promoters that are similar to experimentally characterized seed-specific cis-regulatory elements. Fabaceae SSP gene promoter sequences are also enriched in a novel, seed-specific E2Fb-like motif. Conserved motifs identified in Poaceae SSP gene promoters include a GCN4-like motif, two prolamin-box-like motifs and an Skn-1-like motif. Evidence of the presence of a variant of the TATA-box is found in the SSP gene promoters from the three plant families. Motifs discovered in SSP gene promoters were used to score whole-genome sets of promoters from Arabidopsis, soybean and rice. The highest-scoring promoters are associated with genes coding for different subunits or precursors of seed storage proteins. Conclusion Seed storage protein gene promoter motifs are conserved in diverse species, and different plant families are characterized by a distinct combination

Nectar robbing in Collaea cipoensis (Fabaceae), an endemic shrub of the Brazilian rupestrian grasslands

OpenAIRE

Gelvez-Zúñiga, Irene; Aguirre, Armando; Martén-Rodríguez, Silvana; Matos-Gomes, Vanessa; Barbosa, Arleu; Bordignon, Leandra; Rocha, Rosana; Fernandes, Geraldo W.

2016-01-01

Abstract: Nectar robbery is common in flowering plants with tubular corollas and can affect plant reproductive success. Our study characterized the interaction between potential pollinators and nectar robbers, and assessed the effects on flower abortion in a population of the restricted endemic Collaea cipoensis (Fabaceae) at Serra do Cipó, Brazil. We conducted observations of floral visitors to identify potential pollinators from nectar robbers and described visitor behavior. We also analyze...

The position of prenylation of isoflavonoids and stilbenoids from legumes (Fabaceae) modulates the antimicrobial activity against Gram positive pathogens

NARCIS (Netherlands)

Araya-Cloutier, Carla; Besten, den Heidy M.W.; Aisyah, Siti; Gruppen, Harry; Vincken, Jean Paul

2017-01-01

The legume plant family (Fabaceae) is a potential source of antimicrobial phytochemicals. Molecular diversity in phytochemicals of legume extracts was enhanced by germination and fungal elicitation of seven legume species, as established by RP-UHPLC–UV–MS. The relationship between phytochemical

New species of Lopesia Rübsaamen (Diptera: Cecidomyiidae associated with Andira humilis Mart. ex Benth. (Fabaceae

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Carolina de Almeida Garcia

2017-07-01

Full Text Available A new species of Lopesia Rübsaamen, 1908 induces leaf galls on Andira humilis (Fabaceae in the Cerrado biome (Brazilian savanna of Bahia, Mato Grosso and São Paulo states, Brazil. Larva, pupa, female, and male of this new species of gall midge are described and illustrated in this paper. Keywords: Cerrado, Gall maker, Insect–plant interaction, Neotropical region, Taxonomy

The single evolutionary origin of chlorinated auxin provides a phylogenetically informative trait in the Fabaceae.

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Lam, Hong Kiat; Ross, John J; McAdam, Erin L; McAdam, Scott A M

2016-07-02

Chlorinated auxin (4-chloroindole-3-acetic acid, 4-Cl-IAA), a highly potent plant hormone, was once thought to be restricted to species of the tribe Fabeae within the Fabaceae, until we recently detected this hormone in the seeds of Medicago, Melilotus and Trifolium species. The absence of 4-Cl-IAA in the seeds of the cultivated species Cicer aeritinum from the Cicerae tribe, immediately basal to the Fabeae and Trifolieae tribes, suggested a single evolutionary origin of 4-Cl-IAA. Here, we provide a more robust phylogenetic placement of the ability to produce chlorinated auxin by screening key species spanning this evolutionary transition. We report no detectable level of 4-Cl-IAA in Cicer echinospermum (a wild relative of C. aeritinum) and 4 species (Galega officinalis, Parochetus communis, Astragalus propinquus and A. sinicus) from tribes or clades more basal or sister to the Cicerae tribe. We did detect 4-Cl-IAA in the dry seeds of 4 species from the genus Ononis that are either basal to the genera Medicago, Melilotus and Trigonella or basal to, but still within, the Fabeae and Trifolieae (ex. Parochetus) clades. We conclude that the single evolutionary origin of this hormone in seeds can be used as a phylogenetically informative trait within the Fabaceae.

Seed Carotenoid and Tocochromanol Composition of Wild Fabaceae Species Is Shaped by Phylogeny and Ecological Factors

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Fernández-Marín, Beatriz; Míguez, Fátima; Méndez-Fernández, Leire; Agut, Agustí; Becerril, José M.; García-Plazaola, José I.; Kranner, Ilse; Colville, Louise

2017-01-01

Carotenoids distribution and function in seeds have been very scarcely studied, notwithstanding their pivotal roles in plants that include photosynthesis and phytohormone synthesis, pigmentation, membrane stabilization and antioxidant activity. Their relationship with tocochromanols, whose critical role in maintaining seed viability has already been evidenced, and with chlorophylls, whose retention in mature seed is thought to have negative effects on storability, remain also unexplored. Here, we aimed at elucidating seed carotenoids relationship with tocochromanols and chlorophylls with regard to phylogenetic and ecological traits and at understanding their changes during germination. The composition and distribution of carotenoids were investigated in seeds of a wide range of wild species across the Fabaceae (the second-most economically important family after the Poaceae). Photosynthetic pigments and tocochromanols were analyzed by HPLC in mature dry seeds of 50 species representative of 5 subfamilies within the Fabaceae (including taxa that represent all continents, biomes and life forms within the family) and at key timepoints during seedling establishment in three species representative of distinct clades. Total-carotenoids content positively correlated with tocopherols in the basal subfamilies Detarioideae, Cercidoideae, and Dialioideae, and with chlorophylls in the Papilionoideae. Papilionoideae lacked tocotrienols and had the highest total-carotenoids, chlorophyll and γ-tocopherol contents. Interestingly, lutein epoxide was present in 72% of the species including several herbs from different subfamilies. Overall, species original from temperate biomes presented higher carotenoids and lower tocochromanols levels than those from tropical biomes. Also shrub species showed higher carotenoids content than herbs and trees. During germination, total content of photosynthetic pigments increased in parallel to changes in relative abundance of carotenoids

Chloroplast and mitochondrial microsatellites for Millettia pinnata (Fabaceae) and cross-amplification in related species 1

OpenAIRE

Wang, Yanling; Xie, Hongxian; Yang, Yi; Huang, Yelin; Wang, Jianwu; Tan, Fengxiao

2017-01-01

Premise of the study: Chloroplast and mitochondrial microsatellites were identified to study the population genetics of Millettia pinnata (Fabaceae). Methods and Results: Based on publicly available plastid genome sequence data of M. pinnata, 42 primer pairs were developed, of which 17 displayed polymorphisms across 89 individuals from four populations. For chloroplast loci, two to six alleles were recovered and the unbiased haploid diversity per locus ranged from 0.391 to 0.857. For mitochon...

Seed storage-mediated dormancy alleviation in Fabaceae from campo rupestre

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Naïla Nativel

2015-09-01

Full Text Available ABSTRACTWe studied the effects of seed storage on germination and dormancy alleviation in three species of Fabaceae endemic to campo rupestrein southeastern Brazil. Fresh seeds of Collaea cipoensis, Mimosa maguirei and Mimosa foliolosawere set to germinate and germination of seeds after four, five and 13 years of storage was tested. Seed viability was maintained for all species after the full storage period. Seed storage significantly increased germination percentage and decreased germination time for C. cipoensisand M. foliolosa, suggesting the alleviation of physical dormancy with storage. However, we did not find evidence of dormancy alleviation in M. maguirei since stored seeds showed a decrease in germination in comparison to that of fresh seeds. Our data indicate species-specific storage-mediated dormancy alleviation, which will have important implications for restoration of campo rupestre.

Pollen Viability and Autogamy Fitness in Bauhinia forficata Link (Fabaceae

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Luana Camila Capitani

2018-05-01

Full Text Available ABSTRACT Bauhinia forficata (Fabaceae occurs in many phytophysiognomies of southern Brazil, however its ecological relevance is not well understood. The present study was developed in the Central Depression of Rio Grande do Sul and aimed to determine variations in pollen viability along flowering, ability to perform autogamy and dye efficiency for the viability test. Pollen viability was determined by colorimetry as well as the ability to perform autogamy by isolating floral buds, being evaluated in eleven matrices. Average pollen viability was 81.43%, with the highest average value obtained with the dye 2,3,5- Triphenyltetrazolium Chloride (TTC (84.11%. Safranin was not a good indicator at the tested concentration. No correlation was found between pollen viability and flowering time. The species demonstrated an inability to perform autogamy.

The rediscovery of Astragalus autranii (Fabaceae) on Mt Tomor, south central Albania

DEFF Research Database (Denmark)

Tan, Kit; Shuka, Lulezim; Gjeta, Ermelinda

2015-01-01

Astragalus autranii (Fabaceae) placed by Sytin & Podlech in a section of its own (A. sect. Baldaccia) was described from a single specimen in the Barbey-Boissier Herbarium at Geneva. Our observations show that its placement in A. sect. Hololeuce would also be appropriate. The species was first co...... by Markgraf. Information on habitat, ecology and threat status are also detailed for the first time. Mt Tomor is designated as a protected National Park; however, some of the Astragalus populations may be affected by future road construction....

Neolasioptera pantaneira, a new species of Cecidomyiidae (Diptera) associated with Aeschynomene denticulata (Fabaceae) from Brazil.

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Maia, V C; Catian, G; Leme, F M

2017-03-01

A new species of gall midge that induces stem galls on Aeschynomene denticulata (Fabaceae) is described based on material collected in Pantanal (Mato Grosso do Sul, Brazil). This species is unique among the Brazilian congeners in having spatula with three convex teeth, cruciate, with defined anterolateral extensions, four lateral papillae on each side of the spatula, and three pairs of terminal papillae (larva), four-segmented palpi (adult), 17 flagellomeres (female), ovipositor about 11 times length of seventh tergite.

Anti-methicillin-resistant Staphylococcus aureus (MRSA) activity of Rubiaceae, Fabaceae and Poaceae plants: A search for new sources of useful alternative antibacterials against MRSA infections.

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Sharifi-Rad, M; Iriti, M; Sharifi-Rad, M; Gibbons, S; Sharifi-Rad, J

2016-08-29

In this study, we evaluated the effects of the extracts of the leaves of species from the Rubiaceae (Galium aparine L. and Asperula arvensis L.), Fabaceae (Lathyrus aphaca L. and Vicia narbonensis L.) and Poaceae (Digitaria sanguinalis (L.) Scop. and Hordeum murinum L.) plant families on a wide and extensive panel of isolated methicillin-resistant Staphylococcus aureus strains (MRSA). The effects of the methanolic leaf extracts of Rubiaceae, Fabaceae and Poaceae plants on MRSA were evaluated by the disc diffusion assay and the broth dilution method. Among a total of 177 S. aureus isolates, 92 (51.97%) were found to be methicillin-resistant in an antibiogram and this was confirmed by the presence of the mecA gene in polymerase chain reaction method. All MRSA isolates were sensitive to all extracts. There were dose-dependent inhibitions on tested microorganisms for all plant extracts which showed maximum inhibition zones at a concentration of 300 mg/L. L. aphaca, G. aparine and H. murinum exhibited the highest antibacterial activity on the MRSA strains compared to the positive control (P Fabaceae), G. aparine (Rubiaceae), and H. murinum (Poaceae) proved to have high antibacterial activity on MRSA isolates, thus representing promising antimicrobial agents in clinical settings.

Estudo químico de duas plantas medicinais da amazônia: Philodendron scabrum k. Krause (araceae e Vatairea guianensis aubl. (fabaceae Chemical study of two Amazonian medicinal plants: Philodendron scabrum K. Krause (Araceae and Vatairea guianensis Aubl. (Fabaceae

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Ivonei Ottobelli

2011-01-01

Full Text Available Este trabalho relata o estudo químico de duas plantas medicinais da Amazônia: Philodendron scabrum K. krause (Araceae e Vatairea guianensis Aubl. (Fabaceae. As composições dos óleos essenciais dos cipós de P. scabrum e dos frutos de V. guianensis, respectivamente, foram analisadas em CG-DIC e CG-EM. Os constituintes majoritários dos cipós de P. scabrum foram óxido de cariofileno (19,42%, α-copaeno (16,08% e β-bisaboleno (10,01%; e nos frutos de V. guianensis foram o ácido (9Z-octadecenoico (24,95% e o ácido docosahexaenoico (24,17%. β-sitosterol e o alquilresorcinol 1-hexadecanoil-2,6-dihidroxibenzeno foram isolados do extrato etanólico dos cipós de P. scabrum; e do extrato etanólico dos frutos de V. guianensis, foram isoladas as antraquinonas crisofanol e fisciona. As determinações estruturais foram baseadas em dados de RMN de ¹H e 13C. RMN, uni e bidimensional e comparação com dados da literatura.This work describes the chemical study of two medicinal plants of the Amazon Philodendron scabrum K. Krause (Araceae and Vatairea guianensis Aubl. (Fabaceae. Essential oils composition from stems of Philodendron scabrum K. Krause (Araceae and fruits of Vatairea guianensis Aubl. (Fabaceae, respectively were analyzed in GC-FID and GC-MS. The major constituents from stems of P. scarabum were caryophyllene oxide (22.42%, α-copaene (16.08% and β-bisabolene (12.01% and from fruits of V. guianensis were (9Z-octadecenoic acid (24.95% and docosahexenoic acid (24.17%. β-sitosterol and alkylresorcinol 1-hexadecanoyl-2,6-dihydroxybenzene were isolated from ethanolic extracts from stems of P. scabrum and from ethanolic extracts from fruits of V. guianensis, the athraquinones chrysophanol and physcion were isolated. The structure of isolated compounds we determinate wered based on data from ¹H and 13C NMR, including two dimensional analyses and comparison with literature data.

Tortricid moths (Lepidopotera: Tortricidae) reared from the invasive weed Parkinsonia aculeta (Fabaceae), with comments on their host specificity, biology, and geographic distribution

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During efforts to identify native herbivores of Parkinsonia aculeata L. (Fabaceae: Caesalpiniodeae) as potential biological control agents against this invasive weed in Australia, seven species of Tortricidae were reared in Mexico, Guatemala, Nicaragua, and Venezuela: Amorbia concavana (Zeller), Pla...

Discovery of cyclotides in the fabaceae plant family provides new insights into the cyclization, evolution, and distribution of circular proteins.

Science.gov (United States)

Poth, Aaron G; Colgrave, Michelle L; Philip, Reynold; Kerenga, Bomai; Daly, Norelle L; Anderson, Marilyn A; Craik, David J

2011-04-15

Cyclotides are plant proteins whose defining structural features are a head-to-tail cyclized backbone and three interlocking disulfide bonds, which in combination are known as a cyclic cystine knot. This unique structural motif confers cyclotides with exceptional resistance to proteolysis. Their endogenous function is thought to be as plant defense agents, associated with their insecticidal and larval growth-inhibitory properties. However, in addition, an array of pharmaceutically relevant biological activities has been ascribed to cyclotides, including anti-HIV, anthelmintic, uterotonic, and antimicrobial effects. So far, >150 cyclotides have been elucidated from members of the Rubiaceae, Violaceae, and Cucurbitaceae plant families, but their wider distribution among other plant families remains unclear. Clitoria ternatea (Butterfly pea) is a member of plant family Fabaceae and through its usage in traditional medicine to aid childbirth bears similarity to Oldenlandia affinis, from which many cyclotides have been isolated. Using a combination of nanospray and matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) analyses, we examined seed extracts of C. ternatea and discovered cyclotides in the Fabaceae, the third-largest family of flowering plants. We characterized 12 novel cyclotides, thus expanding knowledge of cyclotide distribution and evolution within the plant kingdom. The discovery of cyclotides containing novel sequence motifs near the in planta cyclization site has provided new insights into cyclotide biosynthesis. In particular, MS analyses of the novel cyclotides from C. ternatea suggest that Asn to Asp variants at the cyclization site are more common than previously recognized. Moreover, this study provides impetus for the examination of other economically and agriculturally significant species within Fabaceae, now the largest plant family from which cyclotides have been described.

Urease inhibitory isoflavonoids from different parts of Calopogonium mucunoides (Fabaceae).

Science.gov (United States)

Ndemangou, Brigitte; Sielinou, Valerie Tedjon; Vardamides, Juliette Catherine; Ali, Muhammad Shaiq; Lateef, Mehreen; Iqbal, Lubna; Afza, Nigaht; Nkengfack, Augustin Ephrem

2013-12-01

The dichloromethane-methanol (1:1) soluble part of Calopogonium mucunoides (Fabaceae) resulted in the isolation of 10 isoflavones (4'-O-methylalpinumisoflavone, 4'-O-methylderrone, alpinumisoflavone, daidzeine, Calopogonium isoflavone A, atalantoflavone, 2',4',5',7-tetramethoxyisoflavone, 7-O-methylcuneantin, cabreuvin and 7-O-methylpseudobaptigenin) and a rotenoid (6a,12a-dehydroxydegueline). Among these, daidzeine, 7-O-methylcuneantin, atalantoflavone and 6a, 12a-dehydroxydegueline have been isolated for the first time from C. mucunoides while remaining are already reported from this source. Structures of all the isolated constituents were elucidated with the aid of NMR spectroscopic and mass spectrometric techniques. Among all the isolated constituents, nine were evaluated for their urease inhibitory potential. However, six were found potent. These include 4'-O-methylderrone, daidzeine, atalantoflavone, 2',4',5',7-tetramethoxyisoflavone, 7-O-methylcuneantin and 6a, 12a-dehydroxydegueline.

A new species of Astragalus (Fabaceae from west coast of Baikal Lake (Irkutsk Oblast

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N. V. Stepantsova

2015-05-01

Full Text Available A new species, Astragalus rytyensis Stepantsova (Fabaceae, growing on the west coast of the lake Baikal, is described. Morphological differences from related taxa – A. versicolor Pall., A. austrosibiricus Schischk., and A. inopinatus Boriss., are discussed and uncertain position of the new species in the system of the genus is emphasized which is intermediate between subg. Phaca (L. Bunge sect. Hemiphaca Bunge and subg. Cercidothrix Bunge sect. Onobrychium Bunge. Ecological and phonological features of A. rytyensis are reported and chromosome numbers of the new (2n = 6x = 48 and related species are counted.

Description of the early stages of Eccopsis galapagana Razowski & Landry (Lepidoptera: Tortricidae), a defoliator of Prosopis juliflora (Sw.) DC (Fabaceae) in Colombia

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The biology and early stages of Eccopsis galapagana Razowski & Landry are described and illustrated for the first time; details of the adults also are provided. Under outbreak conditions, the species has become a serious pest of algarrobo tree (Prosopis juliflora (Sw.) DC.; Fabaceae) in Colombia. Al...

Discovery and Characterization of Novel Cyclotides Originated from Chimeric Precursors Consisting of Albumin-1 Chain a and Cyclotide Domains in the Fabaceae Family*

Science.gov (United States)

Nguyen, Giang Kien Truc; Zhang, Sen; Nguyen, Ngan Thi Kim; Nguyen, Phuong Quoc Thuc; Chiu, Ming Sheau; Hardjojo, Antony; Tam, James P.

2011-01-01

The tropical plant Clitoria ternatea is a member of the Fabaceae family well known for its medicinal values. Heat extraction of C. ternatea revealed that the bioactive fractions contained heat-stable cysteine-rich peptides (CRPs). The CRP family of A1b (Albumin-1 chain b/leginsulins), which is a linear cystine knot CRP, has been shown to present abundantly in the Fabaceae. In contrast, the cyclotide family, which also belongs to the cystine knot CRPs but with a cyclic structure, is commonly found in the Rubiaceae, Violaceae, and Cucurbitaceae families. In this study, we report the discovery of a panel of 15 heat-stable CRPs, of which 12 sequences (cliotide T1–T12) are novel. We show unambiguously that the cliotides are cyclotides and not A1bs, as determined by their sequence homology, disulfide connectivity, and membrane active properties indicated by their antimicrobial activities against Escherichia coli and cytotoxicities to HeLa cells. We also show that cliotides are prevalent in C. ternatea and are found in every plant tissue examined, including flowers, seeds, and nodules. In addition, we demonstrate that their precursors are chimeras, half from cyclotide and the other half from Albumin-1, with the cyclotide domain displacing the A1b domain in the precursor. Their chimeric structures likely originate from either horizontal gene transfer or convergent evolution in plant nuclear genomes, which are exceedingly rare events. Such atypical genetic arrangement also implies a different mechanism of biosynthetic processing of cyclotides in the Fabaceae and provides new understanding of their evolution in plants. PMID:21596752

Carbon and nutrient stocks of three Fabaceae trees used for forest restoration and subjected to fertilization in Amazonia.

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Jaquetti, Roberto K; Gonçalves, José Francisco C

2017-01-01

Amazonia is crucial to global carbon cycle. Deforestation continues to be one of the main causes of the release of C into the atmosphere, but forest restoration plantations can reverse this scenario. However, there is still diffuse information about the C and nutrient stocks in the vegetation biomass. We investigated the carbon and nutrient stocks of Fabaceae trees (Inga edulis, Schizolobium amazonicum and Dipteryx odorata) subjected to fertilization treatments (T1 - no fertilization; T2 - chemical; T3 - organic; and T4 - organic and chemical fertilization) in a degraded area of the Balbina Hydroelectric Dam, AM - Brazil. As an early successional species, I. edulis stocked more C and nutrients than the other two species independent of the fertilization treatment, and S. amazonicum stocked more C than D. odorata under T1 and T4. The mixed species plantation had the potential to stock 4.1 Mg C ha-1 year-1, while I. edulis alone could stock 9.4 Mg C ha-1 year-1. Mixing species that rapidly assimilate C and are of significant ecological and commercial value (e.g., Fabaceae trees) represents a good way to restore degraded areas. Our results suggest that the tested species be used for forest restoration in Amazonia.

Pollen grain morphology of Fabaceae in the Special Protection Area (SPA) Pau-de-Fruta, Diamantina, Minas Gerais, Brazil.

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Luz, Cynthia F P da; Maki, Erica S; Horák-Terra, Ingrid; Vidal-Torrado, Pablo; Mendonça Filho, Carlos Victor

2013-01-01

The presented paper considered the pollen morphology of thirteen species belonging to seven genera of the Fabaceae family occurring in the Pau-de-Fruta Special Protection Area (SPA), Diamantina, state of Minas Gerais, Brazil. The pollen grains of six species of Chamaecrista [C. cathartica (Mart.) H.S. Irwin & Barneby, C. debilis Vogel, C. flexuosa (L.) Greene, C. hedysaroides (Vogel) H.S. Irwin & Barneby, C. glandulosa (L.) Greene, and C. papillata H.S. Irwin & Barneby] have a similar morphology, characterized by three long colporated apertures with a central constriction. The species share specific morphological features regarding pollen size, endoaperture type (circular, lalongate or lolongate) and SEM ornamentation patterns of the exine (rugulate with perforations or perforate). Andira fraxinifolia Benth., Dalbergia miscolobium Benth, Galactia martii DC, Periandra mediterranea (Vell.) Taub., Senna rugosa (G.Don) H.S. Irwin & Barneby and Zornia diphylla (L.) Pers showed different pollen types in small to large size; oblate spheroidal to prolate form; colpus or colporus apertures; circular, lalongate or lolongate endoapertures and distinctive SEM ornamentation patterns of the exine (perforate, microreticulate, reticulate or rugulate with perforations). Only Stryphnodendron adstringens (Mart.) Coville presents polyads. The pollen morphology variation of these species allowed the Fabaceae family to be characterized as eurypalynous in the SPA Pau-de-Fruta.

Carbon and nutrient stocks of three Fabaceae trees used for forest restoration and subjected to fertilization in Amazonia

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ROBERTO K. JAQUETTI

2017-08-01

Full Text Available ABSTRACT Amazonia is crucial to global carbon cycle. Deforestation continues to be one of the main causes of the release of C into the atmosphere, but forest restoration plantations can reverse this scenario. However, there is still diffuse information about the C and nutrient stocks in the vegetation biomass. We investigated the carbon and nutrient stocks of Fabaceae trees (Inga edulis, Schizolobium amazonicum and Dipteryx odorata subjected to fertilization treatments (T1 - no fertilization; T2 - chemical; T3 - organic; and T4 - organic and chemical fertilization in a degraded area of the Balbina Hydroelectric Dam, AM - Brazil. As an early successional species, I. edulis stocked more C and nutrients than the other two species independent of the fertilization treatment, and S. amazonicum stocked more C than D. odorata under T1 and T4. The mixed species plantation had the potential to stock 4.1 Mg C ha-1 year-1, while I. edulis alone could stock 9.4 Mg C ha-1 year-1. Mixing species that rapidly assimilate C and are of significant ecological and commercial value (e.g., Fabaceae trees represents a good way to restore degraded areas. Our results suggest that the tested species be used for forest restoration in Amazonia.

The genus Desmodium (Fabaceae)-traditional uses in Chinese medicine, phytochemistry and pharmacology.

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Ma, Xueqin; Zheng, Chengjian; Hu, Changling; Rahman, Khalid; Qin, Luping

2011-11-18

Plants of the genus Desmodium (Fabaceae), such as Desmodium styracifolium (Osbeck) Merr. and Desmodium gyrans (L. f.) DC., have a long history of medical use in Traditional Chinese Medicine to treat various ailments including rheumatism, pyrexia, dysentery, wounds, cough, malaria, hepatitis, hemoptysis, etc. In the theory of Traditional Chinese Medicine, most species have the effect of relieving internal heat or fever, neutralizing toxins, inhibiting pain, invigorating blood circulation, suppressing cough and alleviating dyspnea. A bibliographic investigation was accomplished by analyzing secondary sources including Chinese Herbal Classics, and worldwide accepted scientific databases (Pubmed, Scopus and Web of Science, SciFinder) were scrutinized for the available information on the ethnopharmacological uses in Chinese medicine, phytochemistry, pharmacology and toxicology of Desmodium species. The genus Desmodium is a large member of the Papilionaceae (Fabaceae) family. It contains about 350 plant species used for both feeding stuffs and herbal medicines, of which only about 30 species have been phytochemically or pharmacologically investigated. Desmodium plant extracts, as well as the active principles, have been experimentally studied for their anti-inflammatory, cytotoxic, antidiabetic, antinephrolithic, antibacterial, and nootropic activities in vitro or in vivo. And so far, a total of 212 compounds have been isolated from 15 Desmodium species and characterized mainly as flavonoids and alkaloids, followed by terpenoids, steroids, phenols, phenylpropanoids, glycosides and a number of volatile oils. The remaining unrevealed species are recorded chiefly in Asia and Africa being used in empirical treatment for various diseases. Desmodium species have long been used in TCM to treat various ailments. Available scientific references revealed that the traditional medical uses of some important Desmodium species in TCM have been evaluated by modern pharmacological

Tolerância à inundação: aspectos da anatomia ecológica e do desenvolvimento de Sesbania virgata (Cav. Pers. (Fabaceae

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Viviane M. Davanso-Fabro

1998-08-01

Full Text Available Plantas de Sebania virgata (Cav. Pers. (Fabaceae cultivadas em casa de vegetação foram alagadas por 40 dias. Plantas alagadas apresentaram aumento do peso da matéria seca e comprimento, acentuadas rachaduras corticais e intumescimento cortical esponjoso em caules e raízes, raízes superficiais e raízes adventícias. É possível que a plasticidade morfo-anatômica apresentada por esta espécie esteja contribuindo para o seu estabelecimento em solos hipóxicos.Twenty days seedlings of Sesbania virgata (Cav. Pers. (Fabaceae cultivated in green house were flooded by forty days. Flooded plants presented increasing of dry weight and lenght, evident cortical fissures and spongy cortical swelling on the stem basis and root, superficial roots on the soil and adventitious roots. It is possible that the morpho-anatomic plasticity presented by this specie is contribuiting for its hipoxic soils stablishment.

Molecular systematics of Indian Alysicarpus (Fabaceae) based on analyses of nuclear ribosomal DNA sequences.

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Gholami, Akram; Subramaniam, Shweta; Geeta, R; Pandey, Arun K

2017-06-01

Alysicarpus Necker ex Desvaux (Fabaceae, Desmodieae) consists of ~30 species that are distributed in tropical and subtropical regions of theworld. In India, the genus is represented by ca. 18 species, ofwhich seven are endemic. Sequences of the nuclear Internal transcribed spacer from38 accessions representing 16 Indian specieswere subjected to phylogenetic analyses. The ITS sequence data strongly support the monophyly of the genus Alysicarpus. Analyses revealed four major well-supported clades within Alysicarpus. Ancestral state reconstructions were done for two morphological characters, namely calyx length in relation to pod (macrocalyx and microcalyx) and pod surface ornamentation (transversely rugose and nonrugose). The present study is the first report on molecular systematics of Indian Alysicarpus.

Anti-inflammatory activity of Adenanthera pavonina L., Fabaceae, in experimental animals Atividade anti-inflamatória de Adenanthera pavonina L., Fabaceae, em animais experimentais

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Arzumand Ara

2010-12-01

Full Text Available Adenanthera pavonina L, Fabaceae alt. Leguminosae, Bengali name 'rakta kombol', is an Indian medicinal plant. It is endemic to Southern China and India, and widely naturalized in Malaysia, Western and Eastern Africa as well as in most islands of both the Pacific and Caribbean regions. This plant has been used in traditional medicine for the treatment of asthma, boil, diarrhoea, gout, inflammations, rheumatism, tumour and ulcers, and as a tonic. The dried and ground bark of A. pavonina L. was extracted, successively, with petroleum ether (PE, dichloromethane (DCM, ethyl acetate (EtOAc and methanol (MeOH, and the resulting extracts were assessed in vivo for anti-inflammatory activity on carrageenan-induced rat hind paw oedema as a model of inflammation. The extracts were administered orally at the doses of 200 and 400 mg/kg body weight, and statistically significant (pAdenanthera pavonina L, Fabaceae, conhecida na região de Bengala por "rakta kombol", é uma planta medicinal endêmica do sul da China e da Índia e amplamente difundida na Malásia, África Ocidental e Oriental, bem como na maioria das ilhas de ambas as regiões do Pacífico e Caribe. Esta planta tem sido utilizada na medicina tradicional para o tratamento da asma, febre, diarréia, gota, inflamações, reumatismo tumor, úlceras, e como tônico. Cascas secas e moídas de A. pavonina foi submetida a extração sucessiva com éter de petróleo (PE, diclorometano (DCM, acetato de etila (AcOEt e metanol (MeOH, e os extratos foram avaliados in vivo para atividade anti-inflamatória induzida por carragenina tendo como ensaio modelo de inflamação edema de pata em ratos.. Os extratos foram administrados por via oral em doses de 200 e 400 mg/kg de peso corporal, e foram observadas efeitos anti-inflamatórios de maneira dose-dependente, estatisticamente significativos (p<0,001. O extrato metanólico (400 mg/kg apresentou 37,10% (p<0,01 de inibição da inflamação na primeira hora do

Cytisus scoparius (Fam. Fabaceae in southern Brazil - first step of an invasion process?

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Rodrigo León Cordero

2016-03-01

Full Text Available The occurrence of Scotch broom Cytisus scoparius (L. Link (Fabaceae, is reported for the first time in Brazil. The species has been registered in the species-rich Campos Sulinos grasslands, in the Campos de Cima da Serra, and in the Serra do Sudeste. Naturalizing populations were frequently formed in natural habitats near to human settlements, where prevailing land uses and disturbances facilitate dispersal and establishment. The plant is an invasive species that has globally caused significant damage to biodiversity and economic losses. In Brazil, the species has a strong potential for spreading into a wide range of ecosystems. The Atlantic Forest biome and part of the Pampa biome, together known as the Campos Sulinos, represent optimal areas for the species. Features of the observed populations and recommendations for management are presented.

Insect Seed Predators in Erythrina falcata (Fabaceae): Identification of Predatory Species and Ecological Consequences of Asynchronous Flowering.

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Pereira, C M; Moura, M O; Da-Silva, P R

2014-06-01

Seed predation by insects exerts negative effects on plant reproduction by limiting the supply of seeds and preventing germination. Seed predators of the family Fabaceae are usually generalists, which increases the rate of predation. One strategy to minimize seed predation, developed by plants from temperate regions, is "escape in time," i.e., flowering before or after the peak of predation. For tropical species, few studies have investigated the strategies used by plants to minimize seed predation. Here, using Erythrina falcata, a tropical species of Fabaceae, we test three main hypotheses: (i) escape in time is a mechanism used by E. falcata to minimize seed predation, (ii) the predators of E. falcata seeds are generalists, and (iii) the biometric variables of the pods can influence seed predation. In order to test these hypotheses, we determined the flowering time of E. falcata, rate of seed predation, the predators insects, and biometric variables of the pods. The analyzed trees were grouped into three classes: "early," "peak," and "late" flowering. The average seed predation rates on trees in the early and late classes were 65% and 50%, respectively, and in the peak class, 80%; thus, our first hypothesis can be accepted. Three species of Lepidoptera and two of Coleoptera were found preying on E. falcata seeds. These species were observed to be generalist predators; thus, our second hypothesis can be accepted. The biometric variables of the pods cannot influence seed predation rate. The ecological consequences of asynchronous flowering on plants and insects are discussed.

Dormancy-breaking requirements of Sophora tomentosa and Erythrina speciosa (Fabaceae seeds

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Carolina Maria Luzia Delgado

2015-03-01

Full Text Available The physical dormancy of seeds has been poorly studied in species from tropical forests, such as the Atlantic Forest. This study aimed to examine the effect of moderate alternating temperatures on breaking the physical dormancy of seeds, the morphoanatomy and histochemistry of seed coats, and to locate the structure/region responsible for water entrance into the seed, after breaking the physical dormancy of seeds of two woody Fabaceae (subfamily Faboideae species that occur in the Brazilian Atlantic Forest: Sophora tomentosa and Erythrina speciosa. To assess temperature effect, seeds were incubated in several temperature values that occur in the Atlantic Forest. For morphological and histochemical studies, sections of fixed seeds were subjected to different reagents, and were observed using light or epifluorescence microscopy, to analyze the anatomy and histochemistry of the seed coat. Treated and non-treated seeds were also analyzed using a scanning electron microscope (SEM to observe the morphology of the seed coat. To localize the specific site of water entrance, the seeds were blocked with glue in different regions and also immersed in ink. In the present work a maximum temperature fluctuation of 15ºC was applied during a period of 20 days and these conditions did not increase the germination of S. tomentosa or E. speciosa. These results may indicate that these seeds require larger fluctuation of temperature than the applied or/and longer period of exposition to the temperature fluctuation. Blocking experiments water inlet combined with SEM analysis of the structures of seed coat for both species showed that besides the lens, the hilum and micropyle are involved in water absorption in seeds scarified with hot water. In seeds of E. speciosa the immersion of scarified seeds into an aniline aqueous solution showed that the solution first entered the seed through the hilum. Both species showed seed morphological and anatomical features for seed

Andiroxylon Thanobolensis Sp.Nov. A New Species of Fossil Wood of Family Fabaceae from Manchar Formation Exposed Near Thanobola Khan, District Jamshoro, Sindh, Pakistan

International Nuclear Information System (INIS)

Khan, S. A.; Ahmed, B.; Tahir, S. S.

2016-01-01

Andiroxylon thanobolensis sp. nov., a new silicified wood has been described and identified from Tertiary Manchar formation exposed near Thanobola Khan, district Jamshoro, Sindh, Pakistan. The xylotomical features of present fossil shows close resemblance with the genus Andira of the Family Fabaceae. The absence of growth ring indicated that plants were growing in tropical type of climate. (author)

Ultrastructure and post-floral secretion of the pericarpial nectaries of Erythrina speciosa (Fabaceae).

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Paiva, Elder Antônio Sousa

2009-10-01

The occurrence of nectaries in fruits is restricted to a minority of plant families and consistent reports of their occurrence are not found associated with Fabaceae, mainly showing cellular details. The present study aims to describe the anatomical organization and ultrastructure of the pericarpial nectaries (PNs) in Erythrina speciosa, a bird-pollinated species, discussing functional aspects of these unusual structures. Samples of floral buds, ovaries of flowers at anthesis and fruits at several developmental stages were fixed and processed by the usual methods for studies using light, and scanning and transmission electron microscopy. Nectar samples collected by filter paper wicks were subjected to chemical analysis using thin-layer chromatography. The PNs are distributed in isolation on the exocarp. Each PN is represented by a single hyaline trichome that consists of a basal cell at epidermal level, stalk cell(s) and a small secretory multicellular head. The apical stalk cell shows inner periclinal and anticlinal walls impregnated by lipids and lignin and has dense cytoplasm with a prevalence of mitochondria and endoplasmic reticulum. The secretory cells show voluminous nuclei and dense cytoplasm, which predominantly has dictyosomes, rough endoplasmic reticulum, plastids, mitochondria and free ribosomes. At the secretory stage the periplasmic space is prominent and contains secretion residues. Tests for sugar indicate the presence of non-reducing sugars in the secretory cells. Nectar samples from PNs contained sucrose, glucose and fructose. The secretory stage of these PNs extends until fruit maturation and evidence suggests that the energetic source of nectar production is based on pericarp photosynthesis. Patrolling ants were seen foraging on fruits during all stages of fruit development, which suggests that the PNs mediate a symbiotic relationship between ants and plant, similar to the common role of many extrafloral nectaries.

Hedysarum L. (Fabaceae: Hedysareae) Is Not Monophyletic - Evidence from Phylogenetic Analyses Based on Five Nuclear and Five Plastid Sequences.

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Liu, Pei-Liang; Wen, Jun; Duan, Lei; Arslan, Emine; Ertuğrul, Kuddisi; Chang, Zhao-Yang

2017-01-01

The legume family (Fabaceae) exhibits a high level of species diversity and evolutionary success worldwide. Previous phylogenetic studies of the genus Hedysarum L. (Fabaceae: Hedysareae) showed that the nuclear and the plastid topologies might be incongruent, and the systematic position of the Hedysarum sect. Stracheya clade was uncertain. In this study, phylogenetic relationships of Hedysarum were investigated based on the nuclear ITS, ETS, PGDH, SQD1, TRPT and the plastid psbA-trnH, trnC-petN, trnL-trnF, trnS-trnG, petN-psbM sequences. Both nuclear and plastid data support two major lineages in Hedysarum: the Hedysarum s.s. clade and the Sartoria clade. In the nuclear tree, Hedysarum is biphyletic with the Hedysarum s.s. clade sister to the Corethrodendron + Eversmannia + Greuteria + Onobrychis clade (the CEGO clade), whereas the Sartoria clade is sister to the genus Taverniera DC. In the plastid tree, Hedysarum is monophyletic and sister to Taverniera. The incongruent position of the Hedysarum s.s. clade between the nuclear and plastid trees may be best explained by a chloroplast capture hypothesis via introgression. The Hedysarum sect. Stracheya clade is resolved as sister to the H. sect. Hedysarum clade in both nuclear and plastid trees, and our analyses support merging Stracheya into Hedysarum. Based on our new evidence from multiple sequences, Hedysarum is not monophyletic, and its generic delimitation needs to be reconsidered.

Caracterização farmacognóstica da espécie Erythrina falcata Benth., Fabaceae

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Emanuel Eustáquio Almeida

Full Text Available Erythrina falcata Benth., Fabaceae, conhecida popularmente no Brasil pelos nomes de mulungu, sapatinho-de-judeu, corticeira-da-serra, muchoco, é usada pela população como planta medicinal indicada como sedativo, ansiolítico ou para doenças do aparelho respiratório. Seu uso indiscriminado, no entanto, pode trazer consequências graves à saúde, devido à forte presença de alcaloides, particularmente nas sementes e na casca. O presente trabalho tem como objetivo estudos fitoquímicos para identificação dos principais grupos de substâncias existentes na espécie, além de estudos morfológicos e histológicos para diferenciação entre outras espécies do gênero.

Chloroplast and mitochondrial microsatellites for Millettia pinnata (Fabaceae) and cross-amplification in related species.

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Wang, Yanling; Xie, Hongxian; Yang, Yi; Huang, Yelin; Wang, Jianwu; Tan, Fengxiao

2017-05-01

Chloroplast and mitochondrial microsatellites were identified to study the population genetics of Millettia pinnata (Fabaceae). Based on publicly available plastid genome sequence data of M. pinnata , 42 primer pairs were developed, of which 17 displayed polymorphisms across 89 individuals from four populations. For chloroplast loci, two to six alleles were recovered and the unbiased haploid diversity per locus ranged from 0.391 to 0.857. For mitochondrial loci, two to four alleles were recovered and the unbiased haploid diversity ranged from 0.264 to 0.740. Sixteen of the 17 screened markers could be successfully amplified in the related species M. pulchra . The 17 microsatellite markers developed here exhibited variation in M. pinnata and 16 presented transferability in the related species M. pulchra , suggesting that these markers will be valuable for genetic studies across M. pinnata and its related species.

Hedysarum L. (Fabaceae: Hedysareae) Is Not Monophyletic – Evidence from Phylogenetic Analyses Based on Five Nuclear and Five Plastid Sequences

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Liu, Pei-Liang; Wen, Jun; Duan, Lei; Arslan, Emine; Ertuğrul, Kuddisi; Chang, Zhao-Yang

2017-01-01

The legume family (Fabaceae) exhibits a high level of species diversity and evolutionary success worldwide. Previous phylogenetic studies of the genus Hedysarum L. (Fabaceae: Hedysareae) showed that the nuclear and the plastid topologies might be incongruent, and the systematic position of the Hedysarum sect. Stracheya clade was uncertain. In this study, phylogenetic relationships of Hedysarum were investigated based on the nuclear ITS, ETS, PGDH, SQD1, TRPT and the plastid psbA-trnH, trnC-petN, trnL-trnF, trnS-trnG, petN-psbM sequences. Both nuclear and plastid data support two major lineages in Hedysarum: the Hedysarum s.s. clade and the Sartoria clade. In the nuclear tree, Hedysarum is biphyletic with the Hedysarum s.s. clade sister to the Corethrodendron + Eversmannia + Greuteria + Onobrychis clade (the CEGO clade), whereas the Sartoria clade is sister to the genus Taverniera DC. In the plastid tree, Hedysarum is monophyletic and sister to Taverniera. The incongruent position of the Hedysarum s.s. clade between the nuclear and plastid trees may be best explained by a chloroplast capture hypothesis via introgression. The Hedysarum sect. Stracheya clade is resolved as sister to the H. sect. Hedysarum clade in both nuclear and plastid trees, and our analyses support merging Stracheya into Hedysarum. Based on our new evidence from multiple sequences, Hedysarum is not monophyletic, and its generic delimitation needs to be reconsidered. PMID:28122062

The concept of ’Musa-pelo and the medicinal use of shrubby legumes (Fabaceae in Lesotho

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A. Moteetee

2007-08-01

Full Text Available In the Kingdom of Lesotho, 20 plant species are commonly known as  'Musa-pelo. The term literally means ‘the one who brings back or tums around the heart’.  'Musa-pelo is traditionally used as a sedative and is given as a first aid treatment to bereaved people who are under severe psychological duress or stress. Of the 20 species known as  'Musa-pelo, 17 belong to nine genera of the Fabaceae  (Argyrolobium, Crotalaria, Indigofera, Lessertia, Lotononis, Melolobium, Sutherlandia, Tephrosia and  Trifolium. The three remaining species namely Cleome monophylla, Heliophila carnosa and  Cysticapnos pruinosa, belong to the families Capparaceae, Brassicaceae and Fumariaceae, respectively. In this paper, the concept of 'Musa-pelo in traditional medicine is explored.

Three new species of Horismenus Walker (Hymenoptera: Eulophidae) associated with seed pods of Pithecellobium dulce (Fabaceae).

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Pikart, Tiago G; Costa, Valmir A; Hansson, Christer; Zanuncio, José C; Serrão, José E

2015-08-04

Horismenus abnormicaulis sp. nov., H. patensis sp. nov. and H. zuleidae sp. nov. (Hymenoptera: Eulophidae), all authored by Pikart, Costa & Hansson, are described from material obtained from seed pods of Pithecellobium dulce (Roxb.) Benth. (Fabaceae) collected in Northeastern Brazil. The seed pods were infested with larvae of Coleoptera (Chrysomelidae (Bruchinae) and Curculionidae). The associations of the Horismenus species and the beetle larvae have not been established. Morphological similarities between these new species and previously described species with host known suggest that H. patensis and H. zuleidae are primary parasitoids of Bruchinae, whereas H. abnormicaulis may act as a hyperparasitoid on other Horismenus species. The three species are compared with similar species of Horismenus.

Evidence That Chlorinated Auxin Is Restricted to the Fabaceae But Not to the Fabeae.

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Lam, Hong Kiat; McAdam, Scott A M; McAdam, Erin L; Ross, John J

2015-07-01

Auxin is a pivotal plant hormone, usually occurring in the form of indole-3-acetic acid (IAA). However, in maturing pea (Pisum sativum) seeds, the level of the chlorinated auxin, 4-chloroindole-3-acetic acid (4-Cl-IAA), greatly exceeds that of IAA. A key issue is how plants produce halogenated compounds such as 4-Cl-IAA. To better understand this topic, we investigated the distribution of the chlorinated auxin. We show for the first time, to our knowledge, that 4-Cl-IAA is found in the seeds of Medicago truncatula, Melilotus indicus, and three species of Trifolium. Furthermore, we found no evidence that Pinus spp. synthesize 4-Cl-IAA in seeds, contrary to a previous report. The evidence indicates a single evolutionary origin of 4-Cl-IAA synthesis in the Fabaceae, which may provide an ideal model system to further investigate the action and activity of halogenating enzymes in plants. © 2015 American Society of Plant Biologists. All Rights Reserved.

Aspectos étnicos, biológicos e químicos de Senna occidentalis (Fabaceae

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T. M. KANEKO

2009-08-01

Full Text Available Senna occidentalis (sin. Cassia occidentalis é um arbusto perene nativo da América do Sul e distribuída em regiões tropicais ao redor do mundo, frequentemente contaminando pastos e culturas de cereais. Inúmeros estudos demonstraram que esta planta é tóxica para animais. Na medicina popular, tribos americanas, africanas e indianas usam preparações da S. occidentalis como tônico, estomáquico, febrífugo, laxante e antimicrobiano. Diversas propriedades biológicas da espécie já foram comprovadas, tais como a antibacteriana, antifúngica, antimalárica, antitumoral e hepatoprotetora. As análises fitoquímicas evidenciaram que as antraquinonas, os flavonóides e outros derivados fenólicos são os seus principais constituintes. Esta revisão apresenta dados etnofarmacológicos, químicos e biológicos publicados na literatura sobre S. occidentalis. Palavras-chave: Senna occidentalis. Cassia occidentalis. Fabaceae. Leguminosae. Caesalpinioideae. Fedegoso.

Morphofunctional Traits and Pollination Mechanisms of Coronilla emerus L. Flowers (Fabaceae)

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Aronne, Giovanna; Giovanetti, Manuela; De Micco, Veronica

2012-01-01

It is accepted that the papilionaceous corolla of the Fabaceae evolved under the selective pressure of bee pollinators. Morphology and function of different parts of Coronilla emerus L. flowers were related to their role in the pollination mechanism. The corolla has a vexillum with red nectar lines, a keel hiding stamens and pistil, and two wing petals fasten to the keel with two notched folds. Pollinators land on the complex of keel and wings, trigger the protrusion of pollen and finally of the stigma from the keel tip. Data on pollen viability and stigma receptivity prove that flowers are proterandrous. The results of hand-pollination experiments confirmed that insects are fundamental to set seed. Interaction with pollinators allows not only the transport of pollen but also the rupture of the stigmatic cuticle, necessary to achieve both allogamy and autogamy. Field observations showed that Hymenoptera, Lepidoptera, and Diptera visited the flowers. Only some of the Hymenoptera landed on the flowers from the front and elicited pollination mechanisms. Most of the insects sucked the nectar from the back without any pollen transfer. Finally, morphological and functional characteristics of C. emerus flowers are discussed in terms of floral larceny and reduction in pollination efficiency. PMID:22666114

Evaluation of the immunotoxicological effects of Dimorphandra mollis Benth., Fabaceae, in rats

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Cássia A. O. Feres

Full Text Available Dimorphandra mollis Benth., Fabaceae, also known as "faveira" or "fava-d'anta", is a plant common to the central woodsy meadow region of Brazil. It is well known for its antioxidant, antiplatelet and, principally, vasoprotective properties. Its principal component is rutin. The objective of this study is the evaluation of the safety of the use of the dried D. mollis extract in rodents. The rutin content of the standardized extract was 76.0±3%. With respect to the biochemical and hematological parameters evaluated, no alterations in the groups of rats that received 1000 and 2000 mg/kg doses of D. mollis were observed, but an increase in eosinophiles occurred. Hyperactivity of the white splenic pulp was detected in the group that received the 2000 mg/kg dose of D. mollis. In the evaluation of the lymphproliferative response with 1000 and 2000 mg/kg, no alterations were observed, and a decrease in IgG was only observed in the studies with a 2000 mg/kg dose. The results obtained with rodents suggest that no toxicity exists with the administration of dried D. mollis extract in a 1000 mg/kg dose.

Potent microbial and tyrosinase inhibitors from stem bark of Bauhinia rufescens (Fabaceae).

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Muhammad, Aminu; Sirat, Hasnah Mohd

2013-10-01

The stem bark extracts of Bauhinia rufescens Lam. (Fabaceae) yielded 6-methoxy-7-methyl-8-hydroxydibenz[b,f]oxepin, alpha-amyrin acetate, beta-sitosterol 3-O-beta-D-xylopyranoside, 4-(2'-Hydroxyphenethyl)-5-methoxy-2-methylphenol, menisdaurin and sequoyitol. Their structures were determined using spectroscopic methods and comparisons with the literature data. For the antimicrobial assay Gram-positive and Gram-negative bacterial and fungal strains were tested, while the tyrosinase inhibition assay utilized L-DOPA as a substrate for the tyrosinase enzyme. 6-Methoxy-7-methyl-8-hydroxydibenz[b,f]oxepin, a-amyrin acetate, beta-sitosterol 3-O-D-xylopyranoside, menisdaurin and sequoyitol showed weak to moderate activities with minimum inhibition concentration (MIC) values in the range of 112.5-900 microg/mL against all bacterial strains, while the MIC values for the fungal strains were in the range of 28.1-450 microg/mL. In the tyrosinase inhibition assay, a-amyrin acetate was found to be moderately active against tyrosinase with an inhibition of 62% at 0.1 mg/mL. This activity was lower than that of the positive control, kojic acid (85%).

Chloroplast and mitochondrial microsatellites for Millettia pinnata (Fabaceae) and cross-amplification in related species1

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Wang, Yanling; Xie, Hongxian; Yang, Yi; Huang, Yelin; Wang, Jianwu; Tan, Fengxiao

2017-01-01

Premise of the study: Chloroplast and mitochondrial microsatellites were identified to study the population genetics of Millettia pinnata (Fabaceae). Methods and Results: Based on publicly available plastid genome sequence data of M. pinnata, 42 primer pairs were developed, of which 17 displayed polymorphisms across 89 individuals from four populations. For chloroplast loci, two to six alleles were recovered and the unbiased haploid diversity per locus ranged from 0.391 to 0.857. For mitochondrial loci, two to four alleles were recovered and the unbiased haploid diversity ranged from 0.264 to 0.740. Sixteen of the 17 screened markers could be successfully amplified in the related species M. pulchra. Conclusions: The 17 microsatellite markers developed here exhibited variation in M. pinnata and 16 presented transferability in the related species M. pulchra, suggesting that these markers will be valuable for genetic studies across M. pinnata and its related species. PMID:28529836

Seasonal variation of phenolic content in galled and non-galled tissues of Calliandra brevipes Benth (Fabaceae: Mimosoidae Variação sazonal do conteúdo fenólico em tecidos galhados e não-galhados de Calliandra brevipes Benth (Fabaceae: Mimosoidae

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Michelle de Lima Detoni

2011-09-01

Full Text Available Two species, Tanaostigmodes ringueleti and T. mecanga, induce distinct galls on Calliandra brevipes Benth (Fabaceae: Mimosoidae, a globose and a fusiform gall morphotype. Seasonal changes of phenolic content in the tissues of the two distinct galls were compared to those of non-galled leaves and stems of the host plants over one year. The variation in the phenolic content profiles was similar in both non-galled and galled tissues, and was primarily associated with changes in the levels of rainfall, indicating a direct response to hydric stress. In periods of drastic changes in water precipitation, the alterations were significantly higher in non-galled than in galled tissues suggesting that the gall inducers might limit the variation in the phenolic concentration for their own benefit.Duas espécies, Tanaostigmodes ringueleti e T. mecanga, induzem galhas distintas em Calliandra brevipes Benth (Fabaceae: Mimosoidae, um morfotipo globoso e um fusiforme. Mudanças sazonais no conteúdo fenólico nos tecidos das duas galhas foram comparadas àquelas de folha e caule não galhados das plantas hospedeiras por um ano. A variação no perfil de conteúdo fenólico foi similar em tecidos galhados e não galhados, sendo associada primariamente às mudanças nos níveis de chuva, constituindo uma resposta direta ao estresse hídrico. Nos períodos de mudanças drásticas na precipitação de água, as alterações foram significativamente maiores em tecido não galhados do que em tecidos galhados, sugerindo que os galhadores estariam limitando a variação do conteúdo fenólico em seu próprio benefício.

Avaliação da toxicidade aguda e potencial neurotóxico do óleo-resina de copaíba (Copaifera reticulata Ducke, Fabaceae

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Camile Giaretta Sachetti

Full Text Available O óleo-resina de copaíba obtido do gênero Copaifera L., Fabaceae, é largamente utilizado na medicina popular como antiinflamatório, antimicrobiano e antitumoral. Porém, informações sobre seu potencial tóxico são escassos na literatura. O objetivo deste estudo foi estabelecer a toxicidade oral aguda e os possíveis efeitos neurotóxicos relacionados à ingestão do óleo-resina de Copaifera reticulata Ducke, Fabaceae, em ratas Wistar. O estudo foi conduzido com quinze ratas nulíparas distribuídas nos grupos de doses 300 e 2000 mg/kg pc de óleo-resina administrado por gavagem. Os resultados obtidos mostraram que nestas doses não houve sinais clínicos de toxicidade ou neurotoxicidade, alteração no consumo de ração ou alteração no peso corpóreo. A dose letal aguda foi estimada como maior que 2000 mg/kg pc e classificada como categoria 5, segundo o Guia OECD 423. Estes resultados indicam que existe uma relativa margem de segurança para o uso do óleo-resina de copaíba como agente terapêutico, embora estudos toxicológicos adicionais sejam ainda necessários, principalmente com a administração repetida de baixas doses.

Aves explorando flores de Erythrina fusca (Leguminosae, Fabaceae durante a estação seca no Pantanal de Mato Grosso Exploitation of Erythrina fusca (Leguminosae, Fabaceae flowers by birds during the dry season in Pantanal of Mato Grosso, Brazil

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Ricardo Parrini

2010-06-01

Full Text Available Estudos recentes têm evidenciado a importância de flores como recurso alimentar de diversas espécies de aves neotropicais. Este estudo teve o objetivo de listar espécies e descrever o comportamento das aves que se alimentaram de recursos florais de Erythrina fusca (Fabaceae no Pantanal Mato-Grossense. Para isso, foram acompanhadas aves que se alimentaram em 14 árvores floridas dessa espécie em um total de cerca de 25 horas de observação. Como resultados, 20 espécies de aves pertencentes a sete famílias taxonômicas foram observadas alimentando-se de recursos florais de E. fusca. Apesar de várias espécies de aves terem apresentado comportamentos destrutivos em maior proporção, algumas espécies, sobretudo das famílias Trochilidae e Icteridae, apresentaram estratégias alimentares compatíveis com o transporte de pólen. O cruzamento dos dados obtidos neste estudo com os da literatura indicam que a família Icteridae pode ter relevante papel na polinização dessa espécie vegetal.Recent studies reported the importance of flowers in the diet of many Neotropical bird species. In this paper we identify and describe the feeding behaviour of bird species that feed on flower resources of Erythrina fusca (Fabaceae in the Pantanal Mato-Grossense, Brazil. We recorded birds foraging in 14 flowered individuals of E. fusca during 25 hours of observation. We recorded 20 bird species belonging to seven families feeding on the flowers. Several of the observed behaviours were destructive, despite some species, especially the Trochilidae and Icteridae, showed feeding strategies that preserve the integrity of the flowers and are compatible with pollen transportation. The comparison of the data gathered in this study with the available literature indicates that the Icteridae may play an important role in pollination of this tree species.

Finding of No Significant Impact/Finding of No Practicable Alternative: Environmental Assessment of the Privatization of Military Family Housing at MacDill Air Force Base, Florida

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2007-10-09

mimosa (Albizia julibrissin), cattails (Typha spp.), cogon grass (Imperata cylindrical), water hyacinth (Eichhornia crassipes), lantana (Lantana camara...exotic invaders such as Australian pine, mimosa, and cogon grass . Another concern is mangrove tree invasion of drainage ditches. While mangrove

Distribution of the endophytic fungi community in leaves of Bauhinia brevipes (Fabaceae Distribuição da comunidade de fungos endofíticos em folhas de Bauhinia brevipes (Fabaceae

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Mariana Patrícia Amorim Hilarino

2011-12-01

Full Text Available Endophytic fungi represent large, yet unexplored components of biodiversity. This work evaluated the richness and the distribution of endophytes in the leaves of Bauhinia brevipes (Fabaceae. A total of 1110 colonies were recovered from the samples and grouped by their morphological traits into 126 taxa. The total number of taxa according to leaf development was: 102 in mature leaves, 93 in recently expanded leaves and 79 for unfolded leaves. The major endophyte genera were Phomopsis, followed by Dothiorella, Pestalotiopsis and Acremonium. The richness and the isolate numbers of endophytes were not statistically affected by leaf region. However, some taxa were leaf-age specific; six were isolated only from unfolded leaves, nine from recently expanded leaves and 17 were exclusively found in mature leaves. The composition of endophytes varied with leaf region; the similarities (Jaccard's Index among the leaf regions of different leaf ages ranged from 0.36 to 0.46, indicating a high spatial variation in the community of endophytic fungi inside the leaves. The high richness of endophytes in this host plant highlights a significant contribution of fungi to tropical biodiversity and the need for further research in this area.Fungos endofíticos representam um grande e ainda pouco explorado componente da biodiversidade. O trabalho avaliou a riqueza e a distribuição endofítica nas folhas de Bauhinia brevipes (Fabaceae. Foram obtidas 1110 colônias que foram agrupadas, por suas características morfológicas em 126 táxons. O número total de táxons por estágio foliar foi: 102 em folhas maduras, 93 em folhas recém-expandidas e 79 em não expandidas. O principal gênero de endofítico encontrado foi Phomopsis, seguido por Dothiorella, Pestalotiopsis e Acremonium. A riqueza e o número de isolados não foram estatisticamente influenciadas pela região foliar. Contudo, alguns táxons foram específicas de um estágio foliar; seis foram isoladas apenas

Anti-inflammatory activity of Adenanthera pavonina L., Fabaceae, in experimental animals

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Arzumand Ara

2010-11-01

Full Text Available Adenanthera pavonina L, Fabaceae alt. Leguminosae, Bengali name 'rakta kombol', is an Indian medicinal plant. It is endemic to Southern China and India, and widely naturalized in Malaysia, Western and Eastern Africa as well as in most islands of both the Pacific and Caribbean regions. This plant has been used in traditional medicine for the treatment of asthma, boil, diarrhoea, gout, inflammations, rheumatism, tumour and ulcers, and as a tonic. The dried and ground bark of A. pavonina L. was extracted, successively, with petroleum ether (PE, dichloromethane (DCM, ethyl acetate (EtOAc and methanol (MeOH, and the resulting extracts were assessed in vivo for anti-inflammatory activity on carrageenan-induced rat hind paw oedema as a model of inflammation. The extracts were administered orally at the doses of 200 and 400 mg/kg body weight, and statistically significant (p<0.001 anti-inflammatory effects were observed in a dose dependant manner. The MeOH extract (400 mg/kg showed 37.10% (p<0.01 inhibition of inflammation at the first hour of the study and, the DCM extract (400 mg/kg exhibited 33.11% (p<0.001 inhibition of inflammation at the third hour of the study which was comparable with that of reference standard drug dichlofenac sodium. The results of this study supported some of the traditional medicinal uses of this plant.

Anticonvulsant effect of the ethanol extract of Caesalpiniapulcherrima (L. Sw., Fabaceae, leaves

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Dinesh Kumar

2010-08-01

Full Text Available In this study, ethanol extract of Caesalpinia pulcherrima (L. Sw., Fabaceae, leaves (CPEE was investigated for anticonvulsant effect against maximal electroshock (MES and pentylenetetrazole (PTZ induced seizures in rats and mice at dose levels 200 and 400 mg/kg, i.p. respectively. Diazepam (3 mg/kg, i.p. was used as a standard anticonvulsant drug for comparison. CPEE was found to be safe up to the dose of 4000 mg/kg in mice, when administered intraperitoneally. The extract at 400 mg/kg dose produced significant (p<0.01 anticonvulsant effect w.r.t. control against PTZ-induced clonic seizures. In MES-induced seizure model, there were no significant alterations in the onset as well as duration of hind limb extension seizures as compared to control at a dose of 200 mg/kg when administered intraperitoneally. However, the extract (CPEE, 400 mg/kg i.p. significantly (p<0.01 delayed the onset as well as decreased the duration of hind limb extension seizures (HLES as compared to control. However, the extract, CPEE, percentage protection of the animals was increased at higher dose (200 mg/kg in both the models. The results of the study suggest that ethanol extract of Caesalpinia pulcherrima (L. Sw. leaves possess anticonvulsant effect.

Reproductive biology of Bowdichia virgilioides Kunth (Fabaceae = Biologia reprodutiva de Bowdichia virgilioides Kunth (Fabaceae

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André Luiz Gomes da Silva

2011-09-01

Full Text Available The aim of this study was to investigate the reproductive biology of Bowdichia virgilioides in an area of Cerrado (Brazilian Savanna. The study was carried out in Chapadinha, State of Maranhão in northeastern Brazil. Bowdichia virgilioides has cornucopia flowering and annual pattern. Flowering occurred at the beginning of the dry season, between June and August; and fruiting in the middle of this season, between July and October. The anthesis of B. virgilioides is diurnal, and the main flower resource is the nectar. During the flower opening, the anthers becomes dehiscent and thus pollen grains are deposited at the stigma, promoting automatic selfpollination. The species is self-compatible and apomitic. In the study area, they were visited by nine species of bees, four butterflies, two wasps, and two hummingbirds. The visits began in early morning and persisted throughout the day, with a peak of activity between 8:00 and 9:00hours. Species of Centris were the main visitors of B. virgilioides. The butterfly and wasp species were considered resource robbers, and other floral visitors were considered occasional visitors. Although the flowers of B. virgilioides are widely visited, the species shows a high rate of inbreeding because of automatic self-pollination.Este trabalho teve como objetivo estudar a biologia reprodutiva de Bowdichia virgilioides Kunth (Fabaceae e avaliar o papel dos visitantes florais em seu sucesso reprodutivo. Bowdichia virgilioides apresenta padrão de floração anual e do tipo cornucópica. A floração ocorre no início da estação seca, entre os meses de junho e agosto e a frutificação no meio desta estação, entre os meses de julho e outubro. Suas flores são de antese diurna e apresentam néctar como recurso floral. Durante a abertura floral, as anteras se encontram deiscentes e por esta razão há a adesão dos grãos de pólen no estigma da própria flor, promovendo o processo de autopolinização passiva. A esp

Evidence That Chlorinated Auxin Is Restricted to the Fabaceae But Not to the Fabeae1[OPEN

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McAdam, Scott A.M.; McAdam, Erin L.

2015-01-01

Auxin is a pivotal plant hormone, usually occurring in the form of indole-3-acetic acid (IAA). However, in maturing pea (Pisum sativum) seeds, the level of the chlorinated auxin, 4-chloroindole-3-acetic acid (4-Cl-IAA), greatly exceeds that of IAA. A key issue is how plants produce halogenated compounds such as 4-Cl-IAA. To better understand this topic, we investigated the distribution of the chlorinated auxin. We show for the first time, to our knowledge, that 4-Cl-IAA is found in the seeds of Medicago truncatula, Melilotus indicus, and three species of Trifolium. Furthermore, we found no evidence that Pinus spp. synthesize 4-Cl-IAA in seeds, contrary to a previous report. The evidence indicates a single evolutionary origin of 4-Cl-IAA synthesis in the Fabaceae, which may provide an ideal model system to further investigate the action and activity of halogenating enzymes in plants. PMID:25971549

Reproduction of Amorpha canescens (Fabaceae) and diversity of its bee community in a fragmented landscape.

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Slagle, Malinda W; Hendrix, Stephen D

2009-10-01

Loss of insect pollinators due to habitat fragmentation often results in negative effects on plant reproduction, but few studies have simultaneously examined variation in the bee community, site characteristics and plant community characteristics to evaluate their relative effects on plant reproduction in a fragmented habitat. We examined the reproduction of a common tallgrass prairie forb, Amorpha canescens (Fabaceae), in large (>40 ha) and small (level characteristics can influence the bee community visiting any one species. Site size, a common predictor of plant reproduction in fragmented habitats did not contribute to any models of fruit set and was only marginally related to bee diversity one year. Andrena quintilis, one of the three oligolectic bee species associated with A. canescens, was abundant at all sites, suggesting it has not been significantly affected by fragmentation. Our results show that the diversity of bees visiting A. canescens is important for maintaining fruit set and that bee visitation is still sufficient for at least some fruit set in all populations, suggesting these small remnants act as floral resource oases for bees in landscapes often dominated by agriculture.

Feeding behavior of hummingbirds and perching birds on Erythrina speciosa Andrews (Fabaceae flowers in an urban area, Londrina, Paraná, Brazil Comportamento alimentar de beija-flores e Passeriformes nas flores de Erytrhina speciosa Andrews (Fabaceae em uma área urbana de Londrina, Paraná, Brasil

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Luciana Baza Mendonça

2006-03-01

Full Text Available Nine species of birds - seven hummingbirds (Trochilidae and two Passeriformes - were observed visiting the flowers of Erythrina speciosa Andrews (Fabaceae, a hummingbird-pollinated species present on the campus of Londrina State University, Paraná State, Brazil. Nectar in bagged flowers bore little relationship with nectar in flowers opened to foragers either regarding quantity or diurnal pattern of availability. Birds were more frequent early in the morning and their activity on flowers further declined, apparently following the pattern of nectar availability. The manner to which birds probed the flowers and, in consequence, their role on pollination were greatly determined by morphological traits and approaching behavior of birds. E. speciosa seemed best suited for pollination by long-billed hummingbirds but some short to medium-billed species may play some role on its pollination.Nove espécies de aves - sete beija-flores (Trochilidae e duas aves Passeriformes - foram observados visitando as flores de Erythrina speciosa Andrews (Fabaceae, uma espécie polinizada por beija-flores presente no campus da Universidade Estadual de Londrina, Paraná, Brasil. O néctar em flores ensacadas apresentou pouca relação com aquele em flores expostas aos visitantes, tanto em termos de quantidade como em temos de padrão diurno de disponibilidade. As aves foram mais freqüentes de manhã e sua atividade nas flores diminuiu no transcorrer do dia, coincidindo com o padrão de disponibilidade de néctar. O comportamento de visita das aves e, em conseqüência, sua atuação na polinização da espécie foram em grande parte determinadas por características morfológicas e comportamentais destas. E. speciosa parece ser adaptada para polinização por beija-flores de bicos longos, embora espécies com bicos de comprimento curto a médio possam ter algum papel em sua polinização.

Superação de dormência e influência da temperatura, substrato e fotoperíodo na germinação de sementes de Erythrina crista-galli L. (FABACEAE

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Luciano Moura de Mello

2016-11-01

Full Text Available Erythrina crista-galli L. (FABACEAE é uma árvore nativa do Brasil, Uruguai, Paraguai, Bolívia e Argentina. As Regras de Análises de Sementes - RAS não possuem orientações para a realização de testes de germinação para a espécie. O objetivo deste trabalho foi testar o desempenho de tratamentos para a superação de dormência das sementes e recomendar condições adequadas de substrato, temperatura e fotoperíodo para a realização de testes de germinação. O tratamento indicado para a superação da dormência foi a escarificação mecânica e a temperatura ótima para os testes de germinação de 30ºC constantes. Não houve diferença entre tratamentos em relação aos substratos testados nem quanto aos fotoperíodos indicando-se assim o substrato entre papel e com 8h de luz por sua praticidade e economia. Superação de dormência e influência da temperatura, substrato e fotoperíodo na germinação de sementes de Erythrina crista-galli L. (FABACEAE

Transferencia de algunos marcadores moleculares microsatélites de la familia Fabaceae en tarwi (Lupinus mutabilis Sweet

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Michelle C. Chirinos-Arias

2015-01-01

Full Text Available Con el objetivo de analizar la transferencia de 15 iniciadores microsatélites de la familia Fabaceae en Lupinus mutabilis Sweet “tarwi”, escogidos por presentar transferibilidad entre especies y géneros, por su alto índice de contenido polimórfico (PIC y alto grado de heterocigosidad observada y esperada. Se extrajo el ADN de 300 plantas de tarwi, se estandarizaron las condiciones PCR haciendo gradientes de los diferentes componentes del master mix. Para el screening se corrieron los iniciadores en gel de agarosa 3% con algunas muestras. Finalmente se amplificó la población y se corrieron en gel de poliacrilamida 6% por su mayor resolución. Sólo el 6,67% de iniciadores amplificaron pero resultaron ser monomórficos, por lo que no pueden usarse en caracterización molecular. Se propone ocho iniciadores microsatélites para tarwi, los cuales deben ser probados en condiciones de laboratorio.

Importance of nickel in Fabaceae. Pt. 1. Comparative studies on the content of nickel and certain other elements in vegetative parts and seeds

Energy Technology Data Exchange (ETDEWEB)

Horak, O

1985-02-28

Vegetative parts and seeds of 15 Fabaceae were analyzed with respect to concentrations of Ni as well as K, Ca, Mg, Fe, Mn, Zn, Cu and Mo. The distribution pattern of the examined elements is different. For the macronutrients and iron mostly a significant higher concentration could be found in the shoot, whilst micronutrients frequently were accumulated in the seed. Nickel is that element, which is accumulated relatively highest in the seed. This is a criterion for a specific importance of nickel, which is a compound of urease and in this function could be involved in the mobilization of nitrogen storage substances of the seed.

Ormosioxylon chinjiensis sp. nov., a new fossil wood of family Fabaceae from the Chinji formation Salt Range Punjab, Pakistan

International Nuclear Information System (INIS)

Soomro, N.; Arain, B. A.; Rajput, T. M.; Tahir, S. S.

2016-01-01

The present work deals with anatomical study of fossil wood collected from the Chinji formation (72 degree 22 min E, 32 degree 4 min N) of Miocene age exposed at the Chinji National Reserve at salt Range Punjab, Pakistan. The material consisted of a single piece of petrified wood. Taxonomical characters of the fossil wood were compared with modern and fossil wood. The sample wood was found comparable to the family Fabaceae. The closest resemblance of the fossil wood was with the wood of Ormosia. The fossil wood under investigation showed close resemblance of vessels, fibers, parenchyma and xylem rays, with the genus Ormosia but shows differences from already reported species of this genus. Hence it is described as a new species as Ormosioxylon chinjiensis sp. nov. The specific epithet refers to Chinji Formation from which the fossil wood is collected. (author)

Chrysoperla externa (Neuroptera: Chrysopidae and Utetheisa ornatrix (Lepidoptera: Arctiidae on organically grown Crotalaria juncea (Fabaceae Chrysoperla externa (Neuroptera: Chrysopidae e Utetheisa ornatrix (Lepidoptera: Arctiidae sobre Crotalaria juncea (Fabaceae cultivada organicamente

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M.A. Costa

2012-09-01

Full Text Available Chrysoperla externa (Neuroptera: Chrysopidae larvae can avoid foraging on plants of Crotalaria juncea (Fabaceae after the issuance of floral buds, when the prey of Utetheisa ornatrix (Lepidoptera: Arctiidae incorporate toxic pyrrolizidine alkaloids from this plant. This reduces the predation and favors increasing the number of adults and eggs of this defoliator on crops of this plant. The aim of the present paper was to evaluate some biological and ecological aspects of C. externa and U. ornatrix on the organic crop of C. juncea in the EMBRAPA Maize and Sorghum in Sete Lagoas, Minas Gerais State, Brazil. Chrysoperla externa and U. ornatrix were more abundant in the vegetative and flowering stages of C. juncea, respectively, with caterpillars of this defoliator feeding on leaves and seeds of this plant. The duration of the stages/instars, survival, lifetime fecundity, and oviposition showed that the branches of C. juncea are a suitable food for U. ornatrix. The abundance of adults and larvae of C. externa was lower in the flowering and pods stages of C. juncea, respectively, when the postures of U. ornatrix are present, probably due to the toxicity of the eggs of this prey to this predator. During these stages, C. externa may be reared with alternative hosts, and when the crops of C. juncea are scarce, an artificial diet should be used for rearing this defoliator in the laboratory for biological research and the development of biological control tactics.Larvas de Chrysoperla externa (Neuroptera: Chrysopidae podem evitar o forrageamento sobre plantas de Crotalaria juncea (Fabaceae após a emissão de botões florais, quando presas de Utetheisa ornatrix (Lepidoptera: Arctiidae incorporam alcalóides pirrolizidínicos tóxicos dessa planta. Isso reduz a predação e favorece o aumento do número de adultos e ovos desse desfolhador sobre cultivos dessa planta. O objetivo deste trabalho foi avaliar alguns aspectos biológicos e ecológicos de C

Molecular Phylogeny of Gueldenstaedtia and Tibetia (Fabaceae) and Their Biogeographic Differentiation within Eastern Asia.

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Xie, Yan-Ping; Meng, Ying; Sun, Hang; Nie, Ze-Long

2016-01-01

Tibetia and Gueldenstaedtia are two morphologically similar and small genera in Fabaceae, with distributions largely corresponding to the Sino-Himalayan and Sino-Japanese subkingdoms in eastern Asia, respectively. These two genera have confusing relationships based on morphology; therefore, we aimed to provide a clear understanding of their phylogenetic and biogeographic evolution within eastern Asia. In our investigations we included 88 samples representing five Gueldenstaedtia species, five Tibetia species, and outgroup species were sequenced using five markers (nuclear: ITS; chloroplast: matK, trnL-F, psbA-trnH and rbcL). Our phylogenetic results support (1) the monophyly of Tibetia and of Gueldenstaedtia, respectively; and (2) that Tibetia and Gueldenstaedtia are sister genera. Additionally, our data identified that Tibetia species had much higher sequence variation than Gueldenstaedtia species. Our results suggest that the two genera were separated from each other about 17.23 million years ago, which is congruent with the Himalayan orogeny and the uplift of the Tibetan Plateau in the mid Miocene. The divergence of Tibetia and Gueldenstaedtia is strongly supported by the separation of the Sino-Himalayan and Sino-Japanese region within eastern Asia. In addition, the habitat heterogeneity may accelerate the molecular divergence of Tibetia in the Sino-Himalayan region.

Molecular Phylogeny of Gueldenstaedtia and Tibetia (Fabaceae) and Their Biogeographic Differentiation within Eastern Asia

Science.gov (United States)

Xie, Yan-Ping; Meng, Ying; Sun, Hang; Nie, Ze-Long

2016-01-01

Tibetia and Gueldenstaedtia are two morphologically similar and small genera in Fabaceae, with distributions largely corresponding to the Sino-Himalayan and Sino-Japanese subkingdoms in eastern Asia, respectively. These two genera have confusing relationships based on morphology; therefore, we aimed to provide a clear understanding of their phylogenetic and biogeographic evolution within eastern Asia. In our investigations we included 88 samples representing five Gueldenstaedtia species, five Tibetia species, and outgroup species were sequenced using five markers (nuclear: ITS; chloroplast: matK, trnL-F, psbA-trnH and rbcL). Our phylogenetic results support (1) the monophyly of Tibetia and of Gueldenstaedtia, respectively; and (2) that Tibetia and Gueldenstaedtia are sister genera. Additionally, our data identified that Tibetia species had much higher sequence variation than Gueldenstaedtia species. Our results suggest that the two genera were separated from each other about 17.23 million years ago, which is congruent with the Himalayan orogeny and the uplift of the Tibetan Plateau in the mid Miocene. The divergence of Tibetia and Gueldenstaedtia is strongly supported by the separation of the Sino-Himalayan and Sino-Japanese region within eastern Asia. In addition, the habitat heterogeneity may accelerate the molecular divergence of Tibetia in the Sino-Himalayan region. PMID:27632535

Antifeedant activity of botanical crude extracts and their fractions on Bemisia tabaci (Homoptera: Aleyrodidae adults: I. Gliricidia sepium (Fabaceae

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Guillermo Flores

2008-12-01

Full Text Available Bemisia tabaci is an important virus vector on a number of crops worldwide. Therefore, a preventive approach to deal with viral epidemics may be the deployment of repellents or phagodeterrents at earlier stages of plant development (critical period. Thus, the crude extract and four fractions thereof (water, water:methanol, methanol, and diethyl ether of mother-of-cocoa (Gliricidia sepium, Fabaceae were tested for phagodeterrence to B. tabaci adults under greenhouse conditions, on tomato plants, in Costa Rica. Both restricted-choice and unrestricted-choice experiments showed that the crude extract and some fractions exerted such effect on the insect. In the former (in sleeve cages, three fractions caused deterrence at doses as low as 0.1% (methanol, 0.5% (water:methanol and 1.5% (diethyl ether. However, in the latter (plants exposed in a greenhouse no one of the fractions performed well, suggesting that the deterrent principles somehow decomposed under the experimental conditions. Rev. Biol. Trop. 56 (4: 2099-2113. Epub 2008 December 12.Mundialmente, Bemisia tabaci es un importante vector de virus en numerosos cultivos. Por tanto, un enfoque preventivo para enfrentar las epidemias virales podría ser el empleo de sustancias repelentes o fagodisuasivas en las etapas tempranas del desarrollo de las plantas (período crítico. Así, tanto el extracto crudo como cuatro fracciones (agua, agua:metanol, metanol y éter dietílico del madero negro (Gliricidia sepium, Fabaceae fueron evaluadas en cuanto a su actividad fagodisuasiva sobre los adultos de B. tabaci en condiciones de invernadero, utilizando plantas de tomate, en Turrialba, Costa Rica. Tanto los experimentos de escogencia restringida como los de escogencia irrestricta revelaron que el extracto crudo y algunas fracciones mostraron dicha actividad. En los primeros experimentos (en jaulas de manga, tres fracciones causaron fagodisuasión a dosis tan bajas como 0.1% (metanol, 0.5% (agua:metanol y

GERMINAÇÃO DE SEMENTES DE Platymiscium floribundum VOG. (FABACEAE SOB A INFLUÊNCIA DA LUZ E TEMPERATURAS

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Magnólia Martins Alves

2016-01-01

Full Text Available ABSTRACT Platymiscium floribundum Vog., a forest species belonging to the family Fabaceae, has great potential for economic exploitation and can be used both in landscape and in reforestation, in the restoration of degraded areas and permanent preservation.given its importance, this work was, it was aimed to study the influence of light and temperature on seed germination of Platymiscium floribundum . We evaluate the germination and vigor Under constant and alternate temperatures of 25 and 30 0 C in different light regimes: White (LB, green (LV, red-far (LVD, red (LV and absence light (A. The experimental design was completely randomized in a factorial 3 x 5 with four replications of 25 seeds. The variables analyzed were: germination, first count of germination, germination speed index (IGV, length and seedling dry weight (root length, shoot length of seedlings. The seeds of Platymiscium floribundum express their maximum force in illuminated environment independent of the temperature.

Ecology and management of Pericopsis elata (Harms Meeuwen (Fabaceae populations: a review

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Bourland, N.

2012-01-01

Full Text Available Pericopsis elata (Fabaceae is a valuable timber species occurring in moist semi-deciduous African forests. While it is at present substantially reduced, the tree's natural distribution previously covered several distinct areas from Côte d'Ivoire to the Democratic Republic of Congo. This species has been logged since the second half of the 20th century. Because it suffers from a lack of regeneration, P. elata is now included in CITES Appendix II and is recorded as "Endangered A1cd" on the IUCN Red List. As with other long-lived light-demanding species, the survival of P. elata may have been favored by important disturbances that occurred in the Congo Basin during the last millennia. While both international trade and industrial uses of the wood of P. elata are well documented, information about its ecology are very sparse or contradictory, and even absent in some cases (e.g., regarding its effective flowering diameter. Furthermore, data describing the management of P. elata are scarce, including potential solutions to compensate for the deficit of natural regeneration. Along the same lines, genetic studies still remain at an early stage and only vague hypotheses have been offered to explain the origins of the tree's populations. We emphasize the need for new research on those topics. Further studies would be useful in deciding whether P. elata populations can continue to be logged without the species being threatened with extinction. Finally, such research needs to target effective and inexpensive management procedures that could secure the future of the species in a logging context.

Anatomical characters of the phyllode and stem of Acacia podalyriifolia A. Cunn. ex G. Don (Fabaceae

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M.R. Duarte

Full Text Available The Acacia genus has presented various secondary metabolites, such as tannins, flavonoids, alkaloids and gums. Preparations from different species have been applied for diabetes, gastrointestinal disorders and inflammatory diseases in the traditional medicine and have demonstrated cytotoxic, antimicrobial and antiparasitic activities. Acacia podalyriifolia A. Cunn. ex G. Don (Fabaceae is a small wood, indigenous to Australia and cultivated worldwide for its ornamental feature. This work aimed to characterize the anatomy of the phyllode and stem, in order to contribute to the species identification. The botanical material was fixed, sectioned and prepared according to usual light and scanning microtechniques. The epidermal cells, in surface view, are polygonal and coated with striate and thick cuticle, and filaments of epicuticular wax. Paracytic stomata and unicellular non-glandular trichomes are seen. Palisade and ground parenchymas, and minor collateral bundles with xylem directed alternately to upper and lower sides occur in the blade. The midrib shows two collateral bundles facing each other. The stem, in incipient secondary growth, exhibits epidermis, annular collenchyma, sclerenchymatic sheath and collateral vascular organization. Cells containing phenolic compounds and prisms of calcium oxalate are observed.

The position of prenylation of isoflavonoids and stilbenoids from legumes (Fabaceae) modulates the antimicrobial activity against Gram positive pathogens.

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Araya-Cloutier, Carla; den Besten, Heidy M W; Aisyah, Siti; Gruppen, Harry; Vincken, Jean-Paul

2017-07-01

The legume plant family (Fabaceae) is a potential source of antimicrobial phytochemicals. Molecular diversity in phytochemicals of legume extracts was enhanced by germination and fungal elicitation of seven legume species, as established by RP-UHPLC-UV-MS. The relationship between phytochemical composition, including different types of skeletons and substitutions, and antibacterial properties of extracts was investigated. Extracts rich in prenylated isoflavonoids and stilbenoids showed potent antibacterial activity against Listeria monocytogenes and methicillin-resistant Staphylococcus aureus at concentrations between 0.05 and 0.1% (w/v). Prenylated phenolic compounds were significantly (p<0.01) correlated with the antibacterial properties of the extracts. Furthermore, the position of the prenyl group within the phenolic skeleton also influenced the antibacterial activity. Overall, prenylated phenolics from legume seedlings can serve multiple purposes, e.g. as phytoestrogens they can provide health benefits and as natural antimicrobials they offer preservation of foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

A study of the fatty acid and tocochromanol patterns of some Fabaceae (Leguminosae plants from Turkey I

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Sahim, Ahmet

2004-12-01

Full Text Available In this study, the fatty acid, tocopherol, tocotrienol and plastochromanol-8 contents of some selected Fabaceae (Leguminosae species belonging to different genera (Colutea, Vicia, Lathyrus, Gonocytisus, Lupinus, Hedysarum, Onobrychis, Trigonella from Turkey were determined by using GLC and HPLC techniques. Some of the studied species are endemic to Turkey. The seed oils of different Leguminous taxa contained linoleic, oleic and linolenic acids as their major components. The ratios of these fatty acids in the Leguminous genera were found to be highly variable. Palmitic and stearic acids are the major saturated fatty acids in the seed oils. Vicia and Onobrychis patterns showed high similarity in means of qualitative fatty acid concentration. The tocopherol and tocochromanol patterns of the seed oils were also found to be highly variable among the genera investigated here. The total tocopherols was higher than the total tocotrienols. Alpha and gamma tocopherols were also the highest tocopherols present in the whole species. Beta, gamma and delta-tocotrienols were not found in most of the studied leguminous patterns. The results are discussed in view of renewable sources and chemotaxonomy.En este estudio, los contenidos en ácidos grasos, tocoferoles, tocotrienoles y plastocromanol-8 de algunas especies seleccionadas de Fabaceae (Leguminosae, pertenecientes a diferentes géneros (Colutea, Vicia, Lathyrus, Gonocytisus, Lupinus, Hedysarum, Onobrychis, Trigonella de Turquía, fueron determinadas usando técnicas de GLC y HPLC. Algunas de las especies estudiadas son endémicas de Turquía. Los aceites de semillas de los diferentes taxones de leguminosas contenían los ácidos linoleico, oleico y linolénico como principales componentes. Las proporciones de estos ácidos grasos fueron muy variables entre los géneros de leguminosas. Los ácidos palmítico y esteárico son los principales ácidos grasos saturados en los aceites de semillas. Los patrones

Rationale for using Peltophorum africanum (Fabaceae extracts in veterinary medicine

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S.E. Bizimenyera

2005-06-01

Full Text Available Peltophorum africanum (Fabaceae is a deciduous tree widespread in southern Africa. The plant has many ethnomedical and ethnoveterinary uses. Root and bark decoctions are used to treat diarrhoea, dysentery, sore throat, wounds, back and joint pains, HIV-AIDS, venereal diseases and infertility. Pastoralists and rural farmers use the root and bark extracts to treat diarrhoea, dysentery, infertility, and to promote well-being and resistance to diseases in cattle. To evaluate these ethnobotanical leads, dried leaves, stem bark and root bark were extracted with ethanol, acetone, dichloromethane and hexane. Polyphenols in the extract were determined by the Folin-Ciocalteu method with gallic acid as standard. Qualitative antioxidant activity was screened by spraying thin layer chromatograms (TLC of the extracts with 0.2 % 1, 1-diphenyl-2-picryl hydrazyl (DPPH, and quantified with Trolox equivalent antioxidant capacity (TEAC assay. Minimum inhibitory concentration (MIC and total antibacterial activity (TAA were determined by serial microplate dilution for Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis, with gentamicin as standard and tetrazolium violet as growth indicator. Acetone and ethanol extracted the largest quantity of material. Polyphenols concentration was 49.2% in acetone extract of the root and 3.8 % in dichloromethane extract of the leaf. Antioxidant activity of at least 5 antioxidant compounds as measured by TEAC ranged from 1.34 (ethanol extract of the root to 0.01 (hexane extract of the leaf. The total antibacterial activity (volume to which active compounds present in 1 g plant material can be diluted and still inhibit bacterial growth was 1263 mℓ/g for ethanol extract of the root against S. aureus, and 800 mℓ/g for acetone extract of the root against P. aeruginosa. There was substantial activity against both Gram-positive and Gram-negative bacteria, with MIC values of 0.08 mg/mℓ for S

Eriosema (Fabaceae) Species Represent a Rich Source of Flavonoids with Interesting Pharmacological Activities.

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Awouafack, Maurice Ducret; Tane, Pierre; Spiteller, Michael; Eloff, Jacobus Nicolaas

2015-07-01

Many flavonoids have so far been isolated as main secondary metabolites in plant species of the genus Eriosema (Fabaceae), which contains approximately 160 species. A total of 52 flavonoids including isoflavones, dihydroflavonols, flavonols, flavanones, dihydrochalcones, isoflavanone and their pyrano or glucoside derivatives were isolated and characterized from the five species of this genus investigated to date. Total synthesis and semi-synthesis (acetylation, methylation, hydrogenation, and cyclization) of some isolated flavonoids were reported. Due to several significant pharmacological properties (antimicrobial, cytotoxicity, anti-mycobacterial, antioxidant, antiviral, erectile-dysfunction, vasodilatory and hypoglycemic) of the isolated flavonoids and derivatives, more scientists should be interested in investigating Eriosema species. The present review is the first to document all flavonoids that have been reported from the genus Eriosema to date together with their synthetic and semi-synthetic derivatives, and their pharmacological properties. Dihydrochalcones, which are precursors of other classes of flavonoids, are very rare in natural sources and their isolation from Eriosema species may explain the large number of flavonoids found in this genus. It appears that isoflavone could be a marker for species in this genus. The 83 flavonoids (1-83) documented include 52 isolates, 31 semi-synthetic and 3 totally synthetic derivatives. Data were obtained from Google scholar, Pubmed, Scifinder, Sciencedirect, and Scopus. With 52 different flavonoids isolated from only 5 of the approximately 160 species it shows the remarkable chemical diversity of this genus. This compilation of the biological activities and chemical composition may renew the interest of pharmacologists and phytochemists in this genus.

Large-scale phylogeography of the disjunct Neotropical tree species Schizolobium parahyba (Fabaceae-Caesalpinioideae).

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Turchetto-Zolet, Andreia C; Cruz, Fernanda; Vendramin, Giovanni G; Simon, Marcelo F; Salgueiro, Fabiano; Margis-Pinheiro, Marcia; Margis, Rogerio

2012-10-01

Neotropical rainforests exhibit high levels of endemism and diversity. Although the evolutionary genetics of plant diversification has garnered increased interest, phylogeographic studies of widely distributed species remain scarce. Here we describe chloroplast and nuclear variation patterns in Schizolobium parahyba (Fabaceae), a widespread tree in Neotropical rainforests that harbor two varieties with a disjunct distribution. Chloroplast and nuclear sequence analyses yielded 21 and 4 haplotypes, respectively. Two genetic diversity centers that correlate with the two known varieties were identified: the Southeastern Atlantic forest and the Amazonian basin. In contrast, the populations from southern and northeastern Atlantic forests and Andean-Central American forests exhibited low levels of genetic diversity and divergent haplotypes, likely related to historical processes that impact the flora and fauna in these regions, such as a founder's effect after dispersion and demographic expansion. Phylogeographic and demographic patterns suggest that episodes of genetic isolation and dispersal events have shaped the evolutionary history for this species, and different patterns have guided the evolution of S. parahyba. Moreover, the results of this study suggest that the dry corridor formed by Cerrado and Caatinga ecoregions and the Andean uplift acted as barriers to this species' gene flow, a picture that may be generalized to most of the plant biodiversity tropical woodlands and forests. These results also reinforce the importance of evaluating multiple genetic markers for a more comprehensive understanding of population structure and history. Our results provide insight into the conservation efforts and ongoing work on the genetics of population divergence and speciation in these Neotropical rainforests. Copyright © 2012 Elsevier Inc. All rights reserved.

Characterization of Proanthocyanidins from Parkia biglobosa (Jacq. G. Don. (Fabaceae by Flow Injection Analysis — Electrospray Ionization Ion Trap Tandem Mass Spectrometry and Liquid Chromatography/Electrospray Ionization Mass Spectrometry

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Wagner Vilegas

2013-03-01

Full Text Available The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae roots and barks by Liquid Chromatography - Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities.

Enantiostyly in Chamaecrista ramosa (Fabaceae-Caesalpinioideae): floral morphology, pollen transfer dynamics and breeding system.

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Almeida, N M de; Castro, C C de; Leite, A V de Lima; Novo, R R; Machado, I C

2013-03-01

Enantiostyly is a form of reciprocal herkogamy, in which floral morphs present reciprocal differences in the position of sexual elements, and occurs in monomorphic and dimorphic forms. This polymorphism maximises cross-pollination and reduces self-pollination, being very common within the subtribe Cassiinae (Fabaceae). Nevertheless, few studies have investigated the functionality of enantiostyly, particularly in this plant group. The present study aimed to investigate enantiostyly and its functionality in Chamaecrista ramosa, a monomorphic enantiostylous shrub, in an area of coastal vegetation in northeast Brazil. Pollen deposition and capture on the body of floral visitors, the relationship of these data with floral biology and breeding system, and morph ratio were evaluated. Pollen deposition and capture occurred in specific sites of the floral visitor body, showing the functionality of enantiostyly. The floral architecture, associated with the floral visitor behaviour, resulted in indirect pollen deposition on the floral visitor body. This occurred through a loop made by the pollen upon the inner petal surface, similar that generally reported for other Cassiinae. Chamaecrista ramosa is self-compatible, although no fruit set was observed through spontaneous self-pollination. The occurrence and number of floral morphs was similar within clumps. Enantiostyly seems to be advantageous for this species, as it results in efficient pollen capture and deposition, reduces the chances of autogamy and maximises intermorph pollen flow. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

Impact of a gall midge Parkiamyia paraensis (Diptera, Cecidomyiidae on the Amazonian plant Parkia pendula (Fabaceae Impacto do galhador Parkiamyia paraensis (Diptera, Cecidomyiidae sobre a planta da Amazônia Parkia pendula Benth. ex Walp. (Fabaceae

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G. Wilson Fernandes

2007-12-01

Full Text Available We observed the occurrence of large numbers of galls induced by Parkiamyia paraensis (Diptera, Cecidomyiidae on the leaflets of Parkia pendula (Fabaceae in northern Para, Brazil. We addressed two questions in this study: i what is the proportion of attacked plants in the field, and nursery conditions?; and ii what is the impact of galls on the host plant? An average of 86% of the plants were galled in the field. Galled P. pendula were distinct from healthy individuals due to their prostrated architecture and death of terminal shoots. Approximately 50% of the total available leaves and 35% leaflets were attacked by P. paraensis on saplings under nursery conditions. Each one-year old plant supported an average of 1,300 galls, and an average of 60g allocated to galled tissue. Otherwise, attacked individuals were taller and heavier than healthy plants. Attacked plants weighed five times more than healthy plants. When the weight of the galls was removed, the total weight (aerial part without galls of attacked plants was drastically reduced, indicating that most of the biomass of attacked plants was due to the attack by P. paraensis galls. Although the data indicate a paradox, as young plants attacked by the galling herbivore appear to develop more vigorously than unattacked plants, we suggest that P. paraensis negatively affect P. pendula development.Observou-se a ocorrência de um grande número de galhas induzidas por Parkiamyia paraensis (Diptera, Cecidomyiidae nos folíolos de Parkia pendula (Fabaceae no norte do Pará, Brasil. Este estudo foi direcionado para responder duas perguntas: i qual é a proporção de plantas atacadas no campo e em condições de estufa? e ii qual é o impacto das galhas na planta hospedeira? Uma média de 86% das plantas apresentaram galhas no campo. Indivíduos com galhas de P. pendula eram distintos dos indivíduos saudáveis devido à arquitetura curvada e pela morte dos ramos terminais. Aproximadamente 50% do

Evaluation Introduction Albizia julibrissin Durazz in Kherson City

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Boiko Tatiana

2017-01-01

Full Text Available The article raised questions diversification of ornamental plants for landscaping of Kherson city. We consider the effectiveness of widespread use in gardening Kherson city highly ornamental exotic species albutsiya lankaran. The rapid growth of plants, indiscriminateness to soil fertility, the ability to abundant seed and coppice restoration, resistance to the conditions of urban areas makes albutsiya promising for widespread use in gardening. In the course of the studies found that albutsiya lankaran rated as mild winter-hardy and moderately drought-resistant species, in desert climate conditions regularly damaged but recovered. Maximum decorative displays at the correct location: maximum light and moderate soil moisture. The plant shows high resistance to diseases and pests.

An acyltransferase gene that putatively functions in anthocyanin modification was horizontally transferred from Fabaceae into the genus Cuscuta

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Ting Sun

2016-06-01

Full Text Available Horizontal gene transfer (HGT refers to the flow of genetic materials to non-offspring, and occasionally HGT in plants can improve the adaptation of organisms in new niches due to expanded metabolic capability. Anthocyanins are an important group of water-soluble red, purple, or blue secondary metabolites, whose diversity results from modification after the main skeleton biosynthesis. Cuscuta is a stem holoparasitic genus, whose members form direct connection with hosts to withdraw water, nutrients, and macromolecules. Such intimate association is thought to increase the frequency of HGT. By transcriptome screening for foreign genes in Cuscuta australis, we discovered that one gene encoding a putative anthocyanin acyltransferase gene of the BAHD family, which is likely to be involved in anthocyanin modification, was acquired by C. australis from Fabaceae through HGT. The anthocyanin acyltransferase-like (AT-like gene was confirmed to be present in the genome assembly of C. australis and the transcriptomes of Cuscuta pentagona. The higher transcriptional level in old stems is consistent with its putative function in secondary metabolism by stabilizing anthocyanin at neutral pH and thus HGT of this AT-like gene may have improved biotic and abiotic resistance of Cuscuta.

A review of the taxonomy, ethnobotany, chemistry and pharmacology of Sutherlandia frutescens (Fabaceae).

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van Wyk, B-E; Albrecht, C

2008-10-28

Sutherlandia frutescens (tribe Galegeae, Fabaceae), a popular plant in traditional medicine, is indigenous to South Africa, Lesotho, southern Namibia and southeastern Botswana. It is chemically, genetically and geographically extremely variable and has been divided into three subspecies and several regional forms. A second species, Sutherlandia tomentosa, is localized along the Cape coast. Sutherlandia is sometimes treated as part of the genus Lessertia. There are numerous vernacular names and a wide diversity of uses, including poor appetite, indigestion, stomach complaints, dysentery, colds, influenza, kidney conditions, fever, diabetes, internal cancers, uterine troubles, liver conditions, backache, rheumatoid arthritis, urinary tract infections, stress and anxiety, dropsy and heart failure. Notable is the use as a bitter tonic ("blood purifier"), anti-stress medication ('musa-pelo) and, at least since 1895, specifically as a cancer tonic (both as treatment and as prophylaxis). Externally it is applied to haemorrhoids, inflamed wounds and eye infections. Recent in vitro and in vivo studies have shown antiproliferative, anti-HIV, anti-diabetic, anti-inflammatory, analgesic, antibacterial, anti-stress, anticonvulsant and antithrombotic activities. Aqueous extracts often differ in activity from organic solvent extracts. The presence of high levels of free amino acids, non-protein amino acids such as canavanine and GABA, the cyclitol pinitol, flavonols and triterpenes (including SU1, a cycloartane-type triterpene saponin) provide plausible hypotheses on how these compounds, individually or collectively, may be responsible for the reputed efficacy in a wide range of ailments. Results of animal studies, as well as a phase I clinical study, have shown no indications of toxicity. Sufficient preclinical data are now available to justify controlled clinical studies.

Notes à La Flore de Corse, XXV

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Jeanmonod, Daniel

2015-01-01

These “notes” deal with 110 noteworthy taxa amongst which 21 are new to the island's flora. One of these taxa is native: Reseda alba subsp. hookeri and 20 are introduced: Abies pinsapo, Acer ×coriaceum, Albizia julibrissin, Arundo micrantha, Azolla filiculoides, Bolboschoenus laticarpus, Digitaria ciliaris, Digitaria violascens, Eucalyptus camaldulensis, E. globulus, Genista januensis subsp. lydia, Hedera helix subsp. maroccana, Morus kagayamae, Oenothera rosea, Paspalum vaginatum, Puccinelli...

Geographical isolation caused the diversification of the Mediterranean thorny cushion-like Astragalus L. sect. Tragacantha DC. (Fabaceae).

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Hardion, Laurent; Dumas, Pierre-Jean; Abdel-Samad, Farah; Bou Dagher Kharrat, Magda; Surina, Bostjan; Affre, Laurence; Médail, Frédéric; Bacchetta, Gianluigi; Baumel, Alex

2016-04-01

Understanding the origin and evolution of Mediterranean vascular flora within the long-term context of climate change requires a continuous study of historical biogeography supported by molecular phylogenetic approaches. Here we provide new insights into the fascinating but often overlooked diversification of Mediterranean xerophytic plants. Growing in some of the most stressing Mediterranean environments, i.e. coastal and mountainous opened habitats, the circum-Mediterranean Astragalus L. sect. Tragacantha DC. (Fabaceae) gathers several thorny cushion-like taxa. These have been the subjects of recent taxonomical studies, but they have not yet been investigated within a comprehensive molecular framework. Bayesian phylogenetics applied to rDNA ITS sequences reveal that the diversification of A. sect. Tragacantha has roots dating back to the Pliocene, and the same data also indicate an eastern-western split giving rise to the five main lineages that exist today. In addition, AFLP fingerprinting supports an old east-west pattern of vicariance that completely rules out the possibility of a recent eastern origin for western taxa. The observed network of genetic relationships implies that contrary to what is widely claimed in the taxonomic literature, it is range fragmentation, as opposed to a coastal-to-mountain ecological shift, that is likely the main driver of diversification. Copyright © 2016 Elsevier Inc. All rights reserved.

EVALUATION OF DIFFERENT PRE-GERMINATIVE METHODS FOR THREE TREE SPECIES OF THE FABACEAE FAMILY IN DIFFERENT ENVIRONMENTS

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R N Costa

2018-02-01

Full Text Available The Sesbania virgata (Cav. Pers., Mimosa caesalpiniifolia Benth. and Cassia grandis L.f. species belong to the Fabaceae family, are characterized by their seeds present a dormant state, which limits the germination. The aim of this study was to evaluate the efficiency of pre-germination treatments to overcome dormancy these species. Seeds were collected from matrix trees, located in Agreste of Alagoas and the research developed at the Federal University of Alagoas – Campus de Arapiraca. Overcoming of dormancy was studied in laboratory and greenhouse, where they were employed eight treatments with four replications of 25 seeds, in a completely randomized design: immersion in sulfuric acid (in three periods of immersion, depending on species, scarification with sandpaper, immersion in hot water at 80 °C (2.5 and 5 minutes, imbibition for 24 hours in distilled water and control (seeds without the application of any treatment. The evaluation of the results was made through of germination and emergence percentage; germination and emergence speed index and germination and emergence average time. The pre-germination treatments, mechanical scarification with sandpaper and chemical scarification with sulfuric acid in different immersion times were the most efficient to overcome the seeds dormancy of Sesbania virgata, Mimosa caesalpiniifolia and Cassia grandis Independent of the studied environments.

Co-processed extracts of Cassia angustifolia Vahl, Fabaceae, and Maytenus ilicifolia (Schrad. Planch., Celastraceae, for production of high load tablets

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Verônica M. L. Alves

2011-06-01

Full Text Available The aim of this study was to investigate the feasibility of a co-processing technique for improving the manufacturing properties of Maytenus ilicifolia (Schrad. Planch., Celastraceae, and Cassia angustifolia Vahl, Fabaceae, extracts in order to obtain tablets containing a high dose of such extracts. An experimental mixture design was used to optimise the formulation composition. Flowability parameters, such as compressibility index, time flow and angle of repose, were determined. Additional important industrial parameters, such as granulometry, bulk density and moisture stability, were also studied. The results demonstrated that co-processing technique was able to improve the flowability of vegetal extracts, making these materials suitable for a direct compression process. The contour plots revealed that formulations with a higher amount of lactose produced the best flow results as well as a larger particle size and a greater bulk density. Tablets from co-processed extracts containing lactose as majority diluent showed appropriate physical-chemical characteristics and presented a more stable moisture sorption behaviour compared to commercial gelatine capsules.

Effects of the hydroethanolic extract of Mucuna pruriens (L.) DC (Fabaceae) on haematological profile in normal and haloperidol treated rats.

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Akindele, Abidemi J; Busayo, Fadeyibi I

2011-01-01

Mucuna pruriens (L.) DC (Fabaceae) is a climbing plant claimed in traditional medicine to possess anti-anaemic effect. The study is to investigate the effects of the hydroethanolic extract of M. pruriens (MP) on haematological profile in normal and haloperidol treated rats. MP was administered p.o. at doses of 50, 100, 200, and 400 mg/kg to groups of rats daily for 28 days. Control animals received distilled water. Rats were sacrificed on the 28th day and blood samples collected for evaluation of haematological parameters and serum iron. Another set of animals received MP p.o. at same doses but along with haloperidol (0.2 mg/kg, i.p.) daily for 4 days. Three other groups of rats received distilled water, haloperidol, and MP at 400 mg/kg alone. Haematological parameters and serum iron were determined. Extract iron content, phytochemical analysis and acute toxicity studies were also carried out. MP administered to normal rats for 28 days significantly (p Mucuna pruriens possibly possess beneficial effects in anaemic conditions especially associated with iron deficiency.

Evolution in the Amphi-Atlantic tropical genus Guibourtia (Fabaceae, Detarioideae), combining NGS phylogeny and morphology.

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Tosso, Félicien; Hardy, Olivier J; Doucet, Jean-Louis; Daïnou, Kasso; Kaymak, Esra; Migliore, Jérémy

2018-03-01

Tropical rain forests support a remarkable diversity of tree species, questioning how and when this diversity arose. The genus Guibourtia (Fabaceae, Detarioideae), characterized by two South American and 13 African tree species growing in various tropical biomes, is an interesting model to address the role of biogeographic processes and adaptation to contrasted environments on species diversification. Combining whole plastid genome sequencing and morphological characters analysis, we studied the timing of speciation and diversification processes in Guibourtia through molecular dating and ancestral habitats reconstruction. All species except G. demeusei and G. copallifera appear monophyletic. Dispersal from Africa to America across the Atlantic Ocean is the most plausible hypothesis to explain the occurrence of Neotropical Guibourtia species, which diverged ca. 11.8 Ma from their closest African relatives. The diversification of the three main clades of African Guibourtia is concomitant to Miocene global climate changes, highlighting pre-Quaternary speciation events. These clades differ by their reproductive characters, which validates the three subgenera previously described: Pseudocopaiva, Guibourtia and Gorskia. Within most monophyletic species, plastid lineages start diverging from each other during the Pliocene or early Pleistocene, suggesting that these species already arose during this period. The multiple transitions between rain forests and dry forests/savannahs inferred here through the plastid phylogeny in each Guibourtia subgenus address thus new questions about the role of phylogenetic relationships in shaping ecological niche and morphological similarity among taxa. Copyright © 2017 Elsevier Inc. All rights reserved.

Differentiation in a geographical mosaic of plants coevolving with ants: phylogeny of the Leonardoxa africana complex (Fabaceae: Caesalpinioideae) using amplified fragment length polymorphism markers.

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Brouat, C; McKey, D; Douzery, E J P

2004-05-01

Comprising four allopatric subspecies that exhibit various grades of ant-plant interactions, from diffuse to obligate and symbiotic associations, the Leonardoxa africana complex (Fabaceae, Caesalpinioideae) provides a good opportunity to investigate the evolutionary history of ant-plant mutualisms. A previous study of the L. africana complex based on chloroplast DNA noncoding sequences revealed a lack of congruence between clades suggested by morphological and plastid characters. In this study, we analysed phylogenetic relationships within the L. africana complex using a Bayesian probability approach on amplified fragment length polymorphism markers. The results reported permit partial validation of the four subspecies of L. africana previously defined by morphological and ecological markers. Incongruences between phylogenies based on chloroplast DNA and amplified fragment length polymorphism markers are discussed in the light of morphological and ecological data, and confronted with hypotheses of convergence, lineage sorting and introgression.

Análise da pluviosidade e do efeito de borda sobre os teores de flavonóides em Bauhinia cheilantha (Bong. Steud., Fabaceae

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Tadeu J. da S. Peixoto Sobrinho

Full Text Available Este estudo avaliou a influência do efeito de borda e da pluviosidade sobre a produção de flavonóides em indivíduos de Bauhinia cheilantha (Bong. Steud., Fabaceae, em uma área de caatinga no estado de Pernambuco, Nordeste do Brasil. Foi utilizada metodologia analítica por complexação com cloreto de alumínio para quantificar a concentração de flavonóides contidos nos extratos foliares de B. cheilantha, por meio de espectrofotometria no visível. De forma geral, o efeito de borda afeta a produção de flavonóides, entretanto, não foi possível correlacionar a produção de flavonóides e a pluviosidade, demonstrando que a espécie avaliada utiliza outra estratégia como resposta às pressões ambientais.

Leishmanicidal Metabolites from Cochliobolus sp., an Endophytic Fungus Isolated from Piptadenia adiantoides (Fabaceae)

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Campos, Fernanda Fraga; Rosa, Luiz Henrique; Cota, Betania Barros; Caligiorne, Rachel Basques; Teles Rabello, Ana Lúcia; Alves, Tânia Maria Almeida; Rosa, Carlos Augusto; Zani, Carlos Leomar

2008-01-01

Protozoan parasites belonging to genera Leishmania and Trypanosoma are the etiological agents of severe neglected tropical diseases (NTDs) that cause enormous social and economic impact in many countries of tropical and sub-tropical areas of the world. In our screening program for new drug leads from natural sources, we found that the crude extract of the endophytic fungus Cochliobolus sp. (UFMGCB-555) could kill 90% of the amastigote-like forms of Leishmania amazonensis and inhibit by 100% Ellman's reagent reduction in the trypanothione reductase (TryR) assay, when tested at 20 µg mL−1. UFMGCB-555 was isolated from the plant Piptadenia adiantoides J.F. Macbr (Fabaceae) and identified based on the sequence of the internally transcribed spacer (ITS) regions of its ribosomal DNA. The chromatographic fractionation of the extract was guided by the TryR assay and resulted in the isolation of cochlioquinone A and isocochlioquinone A. Both compounds were active in the assay with L. amazonensis, disclosing EC50 values (effective concentrations required to kill 50% of the parasite) of 1.7 µM (95% confidence interval = 1.6 to 1.9 µM) and 4.1 µM (95% confidence interval = 3.6 to 4.7 µM), respectively. These compounds were not active against three human cancer cell lines (MCF-7, TK-10, and UACC-62), indicating some degree of selectivity towards the parasites. These results suggest that cochlioquinones are attractive lead compounds that deserve further investigation aiming at developing new drugs to treat leishmaniasis. The findings also reinforce the role of endophytic fungi as an important source of compounds with potential to enter the pipeline for drug development against NTDs. PMID:19079599

Spectrum of allergenic pollen in Karachi and their characterization using conventional and electron microscopy: Potential candidates for allergy vaccines

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Parveen, A.; Noori, M.Y.; Qureshi, M.A.

2015-01-01

Objective: To study the distribution of naturally growing plants with possible allergenic potential and study their pollen morphology in Karachi, Pakistan. Methodology: We performed field surveys of naturally growing plants with possible allergenic potential and studied their pollen morphology using conventional (light) as well as scanning electron microscopy. Results: About 80 allergenic pollen producing species were identified which are distributed in 45 genera and 9 angiospermic families. Grasses belonging to Graminae are most abundant followed by plants from family Fabaceae (Leguminosae). Highly allergenic weeds were also found widely growing in the city areas belonging to Amaranthaceae/Chenopodiaceae family. Conclusion: Our study provides an updated information about the allergenic plants growing in Karachi city. All desensitization efforts should be designed in accordance to the available information regarding the prevalent allergens in the environment so that appropriate therapy can be given to the affected population. (author)

Soil organisms associated to the weed suppressant Crotalaria juncea (fabaceae and its importance as a refuge for natural enemies Organismos de solo associados à supressora de plantas daninhas Crotalaria juncea (fabaceae e sua importância como refúgio para inimigos naturais

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W.S Tavares

2011-09-01

Full Text Available Soil organisms play an important role in organic crops of Crotalaria juncea (Fabaceae and are associated with the natural conservation of the environment. The present study was aimed to investigate the population of soil organisms in the organic culture of C. juncea, as well as its importance as a refuge for natural enemies. Dalbulus maidis (Hemiptera: Cicadellidae, Diabrotica sp. (Coleoptera: Chrysomelidae, Doru luteipes (Dermaptera: Forficulidae, Gryllus assimilis (Orthoptera: Gryllidae, Lagria villosa (Coleoptera: Lagriidae, Melanotus sp. (Coleoptera: Elateridae, Meloidogyne incognita (Tylenchida: Heteroderidae, Nephila clavipes (Araneae: Nephilidae, Orius insidiosus (Hemiptera: Anthocoridae, Pheidole sp. (Hymenoptera: Myrmicidae, Phyllophaga sp. (Coleoptera: Scarabeidae, Procornitermes sp. (Isoptera: Termitidae, Solenopsis sp. (Hymenoptera: Formicidae, and Utetheisa ornatrix (Lepidoptera: Arctiidae were identified in C. juncea. The organisms that were found during a 3-month period in 144 trenches in C. juncea were pest species (84.47% and natural enemies (15.53% as well. Natural enemies had an average of 11.89 individuals per 1.08 m³ of soil cultivated with C. juncea. The abundance of organisms in the pod stage (5.49% of C. juncea was lower than that in the vegetative (83.50% and flowering (11.01% stages. Crotalaria juncea plants can be used as part of a crop system for Integrated Pest Management.Organismos de solo desempenham um importante papel em cultivos orgânicos de Crotalaria juncea (Fabaceae e estão associados com a conservação natural do ambiente. O presente estudo teve como objetivo investigar a população de organismos de solo no cultivo orgânico de C. juncea, bem como sua importância como um refúgio para inimigos naturais. Dalbulus maidis (Hemiptera: Cicadellidae, Diabrotica sp. (Coleoptera: Chrysomelidae, Doru luteipes (Dermaptera: Forficulidae, Gryllus assimilis (Orthoptera: Gryllidae, Lagria villosa (Coleoptera

Endoreduplication intensity as a marker of seed developmental stage in the Fabaceae.

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Rewers, Monika; Sliwinska, Elwira

2012-12-01

Flow cytometry (FCM) can be used to study cell cycle activity in developing, mature and germinating seeds. It provides information about a seed's physiological state and therefore can be used by seed growers for assessing optimal harvest times and presowing treatments. Because an augmented proportion of 4C nuclei usually is indicative of high mitotic activity, the 4C/2C ratio is commonly used to follow the progress of seed development and germination. However, its usefulness for polysomatic (i.e., containing cells with different DNA content) seeds is questioned. Changes in cell cycle/endoreduplication activity in developing seeds of five members of the Fabaceae were studied to determine a more suitable marker of seed developmental stages for polysomatic species based on FCM measurements. Seeds of Phaseolus vulgaris, Medicago sativa, Pisum sativum, Vicia sativa, and Vicia faba var. minor were collected 20, 30, 40, 50, and 60 days after flowering (DAF), embryos were isolated and the proportion of nuclei with different DNA contents in the embryo axis and cotyledon was established. The ratios 4C/2C and (Σ>2C)/2C were calculated. Dried seeds were subjected to laboratory germination tests following international seed testing association (ISTA) rules. Additionally, the absolute nuclear DNA content was estimated in the leaves of the studied species. During seed development nuclei with DNA contents from 2C to 128C were detected; the endopolyploidy pattern depended on the species, seed organ and developmental stage. The cell cycle/endoreduplication parameters correlated negatively with genome size. The (Σ>2C)/2C ratio in the cotyledons reflected the seed developmental stage and corresponded with seed germinability. Therefore, this ratio is recommended as a marker in polysomatic seed research and production instead of the 4C/2C ratio, which does not consider the occurrence of endopolyploid cells. Copyright © 2012 International Society for Advancement of Cytometry.

Toxicity of Millettia ferruginea darasana (family: Fabaceae) against the larvae and adult ticks of Amblyomma variegatum Fabricius a three-host tick in cattle.

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Choudhury, Manash Kumar; Shiferaw, Yoseph; Hussen, Ahmed

2015-06-01

The in vitro toxicity of Millettia ferruginea darasana (family: Fabaceae) was tested against the larvae adult male and female of a three-host tick, Amblyomma variegatum Fabricius (family: Ixodidae or hard tick), known as 'tropical bont tick' parasitic mainly to cattle found in Ethiopia and other equatorial Africa. The 20, 40, 60, 80 and 100 % concentrations of the seed oil extracted with petroleum ether were found to kill all (100 % mortality) larvae after 12, 9, 6, 3 and 1.5 h respectively. The results summarized in the Table 1 was found to be statistically significant at the probability level of p = 0.05. The 100 % concentration of the oil caused 100 % mortality of adult male, adult female and fully engorged female tick after 5, 7 and 12 h respectively. The root and root bark showed less toxicity. The leaves did not show any toxicity. [Table: see text].

Anatomia dos órgãos vegetativos de Hymenaea martiana Hayne (Caesalpinioideae-Fabaceae: espécie de uso medicinal em Caetité-BA Anatomy of vegetative organs of Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae: a species of medicinal use in Caetité-Bahia State, Brazil

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M.S. Silva

2012-01-01

Full Text Available Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae apresenta grande valor na medicina popular em Caetité. A casca, entrecasca do caule e a resina, são utilizadas no tratamento de diversos males. Neste estudo são apresentadas a caracterização anatômica e histoquímica dos órgãos vegetativos. Amostras foram coletadas e processadas segundo técnicas usuais em anatomia vegetal e histoquímica. Todos os órgãos apresentam, em visão transversal, epiderme unisseriada e cavidades secretoras. Cutícula espessa ocorre em todos os órgãos aéreos. A raiz é tetrarca. Colênquima lacunar foi encontrado no caule. Bainha de fibras esclerenquimáticas envolve os feixes vasculares dos órgãos aéreos. Células pétreas ocorrem no pecíolo. Tricomas tectores ocorrem em ambas as faces da folha. A folha é hipoestomática com estômatos paracíticos e o mesofilo é dorsiventral. Cristais de oxalato de cálcio ocorrem no caule, pecíolo e lâmina foliar. Compostos fenólicos ocorrem na raiz, pecíolo e nervura central da folha. Grãos de amido ocorrem na raiz, caule e pecíolo. Lipídios ocorrem em todos os órgãos. Acredita-se que compostos fenólicos e cavidades secretoras de resina podem justificar a utilidade medicinal da espécie pela população de Caetité.Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae shows a great value in folk medicine in Caetité. Its bark, stem-bark and resin are used to treat various ailments. In this study, the anatomical and histochemical characterization of vegetative organs is reported. Samples were collected and processed according to usual techniques of plant anatomy and histochemistry. All organs have, by cross-sectional view, uniseriate epidermis and secretory cavities. Thick cuticle occurs in all aerial organs. The root is tetrarch. Lacunar collenchyma was found in the stem. Sclerenchymatic sheath of fibers surrounds the vascular bundles of the aerial organs. Stone cells occur in the petiole. Trichomes occur

Density dependent interactions between VA mycorrhizal fungi and even-aged seedlings of two perennial Fabaceae species.

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Allsopp, N; Stock, W D

1992-08-01

The interaction of density and mycorrhizal effects on the growth, mineral nutrition and size distribution of seedlings of two perennial members of the Fabaceae was investigated in pot culture. Seedlings of Otholobium hirtum and Aspalathus linearis were grown at densities of 1, 4, 8 and 16 plants per 13-cm pot with or without vesicular-arbuscular (VA) mycorrhizal inoculum for 120 days. Plant mass, relative growth rates, height and leaf number all decreased with increasing plant density. This was ascribed to the decreasing availability of phosphorus per plant as density increased. O. hirtum was highly dependent on mycorrhizas for P uptake but both mycorrhizal and non-mycorrhizal A. linearis seedlings were able to extract soil P with equal ease. Plant size distribution as measured by the coefficient of variation (CV) of shoot mass was greater at higher densities. CVs of mycorrhizal O. hirtum plants were higher than those of non-mycorrhizal plants. CVs of the facultatively mycorrhizal A. linearis were similar for both mycorrhizal and non-mycorrhizal plants. Higher CVs are attributed to resource preemption by larger individuals. Individuals in populations with high CVs will probably survive stress which would result in the extinction of populations with low CVs. Mass of mycorrhizal plants of both species decreased more rapidly with increasing density than did non-mycorrhizal plant mass. It is concluded that the cost of being mycorrhizal increases as plant density increases, while the benefit decreases. The results suggest that mycorrhizas will influence density-dependent population processes of faculative and obligate mycorrhizal species.

Taxonomic study of Onobrychis transcaspica V. Nikitin (Fabaceae in northeastern of Iran with emphasis on altitudinal effect on morphological characters using floristic marker

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Zeinab Toluei

2010-07-01

Full Text Available Onobrychis Miller is the second largest genus of Fabaceae in Iran with nearly 60 species. These species are used as valuable forage plants. Onobrychis sect. Onobrychis with nearly 15 species in Iran is one of the important sections of the genus. Onobrychis transcaspica V. Nikitin, is one of the species of this section that is distributed in NE of Iran. To determine intraspecific variations in O. transcaspica from taxonomic point of view and effective ecological factor, data were collected using special station method. In this way, four special stations were recognized for O. transcaspica in NE of Iran. Results from floristic data (Floristic composition of each special station analysis with MVSP software by PCO method, led to identification of 3 separate groups that was indicative of existence of intraspecific diversity. Morphometric data analysis of individual collected from each special station, by using 65 vegetative and reproductive characters, with PCO and UPGMA methods, confirmed 3 mentioned floristic groups. Ecologic data analysis with CCA Method showed the presence of 3 phenoecodeme based on 3 morphologic groups resulting from altitudinal variations.

Divergence and diversification in North American Psoraleeae (Fabaceae) due to climate change

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Egan, Ashley N; Crandall, Keith A

2008-01-01

Background Past studies in the legume family (Fabaceae) have uncovered several evolutionary trends including differential mutation and diversification rates across varying taxonomic levels. The legume tribe Psoraleeae is shown herein to exemplify these trends at the generic and species levels. This group includes a sizable diversification within North America dated at approximately 6.3 million years ago with skewed species distribution to the most recently derived genus, Pediomelum, suggesting a diversification rate shift. We estimate divergence dates of North American (NAm) Psoraleeae using Bayesian MCMC sampling in BEAST based on eight DNA regions (ITS, waxy, matK, trnD-trnT, trnL-trnF, trnK, trnS-trnG, and rpoB-trnC). We also test the hypothesis of a diversification rate shift within NAm Psoraleeae using topological and temporal methods. We investigate the impact of climate change on diversification in this group by (1) testing the hypothesis that a shift from mesic to xeric habitats acted as a key innovation and (2) investigating diversification rate shifts along geologic time, discussing the impact of Quaternary climate oscillations on diversification. Results NAm Psoraleeae represents a recent, rapid radiation with several genera originating during the Pleistocene, 1 to 2 million years ago. A shift in diversification rate is supported by both methods with a 2.67-fold increase suggested around 2 million years ago followed by a 8.73-fold decrease 440,000 years ago. The hypothesis that a climate regime shift from mesic to xeric habitats drove increased diversification in affected taxa was not supported. Timing of the diversification rate increase supports the hypothesis that glaciation-induced climate changes during the Quaternary influenced diversification of the group. Nonrandom spatial diversification also exists, with greater species richness in the American Southwest. Conclusion This study outlines NAm Psoraleeae as a model example of a recent, rapid

Divergence and diversification in North American Psoraleeae (Fabaceae due to climate change

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Crandall Keith A

2008-12-01

Full Text Available Abstract Background Past studies in the legume family (Fabaceae have uncovered several evolutionary trends including differential mutation and diversification rates across varying taxonomic levels. The legume tribe Psoraleeae is shown herein to exemplify these trends at the generic and species levels. This group includes a sizable diversification within North America dated at approximately 6.3 million years ago with skewed species distribution to the most recently derived genus, Pediomelum, suggesting a diversification rate shift. We estimate divergence dates of North American (NAm Psoraleeae using Bayesian MCMC sampling in BEAST based on eight DNA regions (ITS, waxy, matK, trnD-trnT, trnL-trnF, trnK, trnS-trnG, and rpoB-trnC. We also test the hypothesis of a diversification rate shift within NAm Psoraleeae using topological and temporal methods. We investigate the impact of climate change on diversification in this group by (1 testing the hypothesis that a shift from mesic to xeric habitats acted as a key innovation and (2 investigating diversification rate shifts along geologic time, discussing the impact of Quaternary climate oscillations on diversification. Results NAm Psoraleeae represents a recent, rapid radiation with several genera originating during the Pleistocene, 1 to 2 million years ago. A shift in diversification rate is supported by both methods with a 2.67-fold increase suggested around 2 million years ago followed by a 8.73-fold decrease 440,000 years ago. The hypothesis that a climate regime shift from mesic to xeric habitats drove increased diversification in affected taxa was not supported. Timing of the diversification rate increase supports the hypothesis that glaciation-induced climate changes during the Quaternary influenced diversification of the group. Nonrandom spatial diversification also exists, with greater species richness in the American Southwest. Conclusion This study outlines NAm Psoraleeae as a model example

Role of the lens in controlling physical dormancy break and germination of Delonix regia (Fabaceae: Caesalpinioideae).

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Jaganathan, G K; Wu, G-R; Han, Y-Y; Liu, B L

2017-01-01

Physical dormancy occurs in all three subfamilies of Fabaceae, namely Mimosoideae, Papilionoideae and Caesalpinioideae, making it one of the largest plant families in terms of number of species with physical dormancy. However, little is known about the water gap structure and germination ecology of species in Caesalpinioideae. Freshly collected seeds of Delonix regia (Caesalpinioideae) did not imbibe water, thus they had physical dormancy. Both dry heat and wet heat were effective in breaking dormancy, however, longer duration was required at 80 °C and shorter duration at 90 °C. Seeds buried in the field for 2 years germinated to 21% and 42% after the first and second summer, respectively, compared with 3% germination in seeds at the time of maturity. Seeds incubated at 15/60 °C in the laboratory (mimicking summer conditions) for 3 months supported this conclusion, as dormancy was relieved in 18% and 24% of seeds stored dry and watered intermediately, respectively. All the dormancy breaking treatments resulted in lifting of palisade layers in the lens region to form a circular lid-like opening, i.e. water gap (Type II simple). Blocking experiments confirmed that water entered only through the lens and no secondary water entry point was observed. No apparent changes in morphology/anatomy of the hilum region were noted in dormant and non-dormant (water permeable) seeds. These results suggest that summer temperatures could open the lens in a proportion of seeds every year and that germination occurs during the subsequent wet season in the tropics. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Effects of Retama raetam (Forssk. Webb & Berthel. (Fabaceae on the central nervous system in experimental animals

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Al-Tubuly Rida A.

2011-01-01

Full Text Available Retama raetam (Forssk. Webb & Berthel. (Fabaceae, commonly known as ‘raetam’ or ‘broom bush’, is a desert shrub that grows abundantly in North-African countries, Palestine and Syria. Traditionally, this plant has been used as an abortifacient, a purgative and a vermifuge. In the present study, the effect of the methanol (MeOH extract of the aerial parts of R. raetam on the central nervous system (CNS has been evaluated using a mice model. In the photoelectrical cell test, the extract of R. raetam (ERR at a dose of 125 mg/kg body weight did not exhibit any effect on the spontaneous motor activity in mice. At a dose of 250 mg/kg body weight, ERR increased ambulatory movement, but had no effect on the non-ambulatory movement, while a dose of 375 mg/kg body weight decreased both ambulatory and non-ambulatory movements. The effect of ERR on the anxiety levels and behaviors of mice was investigated using the elevated plus-maze test. At doses of 125, 250 and 375 mg/kg body weight, ERR decreased anxiety levels without showing an effect on the total activity; it did not affect anxiety levels but increased the total activity; it increased anxiety levels and decreased the total activity, respectively. In the diazepam-induced sleep test, ERR increased the onset of sleep without affecting the duration of sleep at the dose of 250 mg/kg body weight. The dose of 375 mg/kg body weight decreased the onset of sleep while increasing the duration of sleep. ERR did not exhibit any effect on the diazepam-induced sleep in the presence of flumazenil or picrotoxin.

In vitro antibacterial, antioxidant and cytotoxic activity of acetone leaf extracts of nine under-investigated Fabaceae tree species leads to potentially useful extracts in animal health and productivity.

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Dzoyem, Jean P; McGaw, Lyndy J; Eloff, Jacobus N

2014-05-05

The Fabaceae family is the second largest family of medicinal plants, containing more than 490 species which are being used as traditional medicine. The aim of this study was to determine the antioxidant and antibacterial activity as well as the cytotoxicity of acetone leaf extracts of nine tree species from the Fabaceae family that have not been investigated well previously for possible use in animal health and production. The antibacterial activity was determined by a serial microdilution method against three Gram-positive and three Gram-negative bacteria. Antioxidant activity was determined using free-radical scavenging assays. The safety of the extracts was ascertained using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on Vero African green monkey kidney cells. Six of the nine acetone extracts had significant antibacterial activity against at least one of the six bacterial species with (MIC 20-80 μg/mL). The Crotalaria capensis extract had the highest activity against Salmonella typhimurium, followed by Indigofera cylindrica with MICs of 20 μg/mL and 40 μg/mL respectively. The Dalbergia nitidula extract had free radical scavenging capacity (IC50 of 9.31±2.14 μg/mL) close to that of the positive control Trolox in the DPPH assay. The Xylia torreana extract also had high activity (IC50 of 14.56±3.96 μg/mL) in the ABTS assay. There was a good correlation between antioxidant activity and total phenolic content (R2 values>0.8). The extracts had weak or no toxicity to Vero cells, compared to the positive control doxorubicin with the LC50 varying from 10.70±3.47 to 131.98±24.87 μg/mL at the concentrations tested. Extracts of D. nitidula, X. torreana, C. capensis and I. cylindrica had a low cytotoxicity and high antimicrobial and/or antioxidant activity. These species are therefore promising candidates for the development of useful antimicrobial/antioxidant preparations with a low cytotoxicity that may be useful in promoting

Impactos da invasão de Prosopis juliflora (sw. DC. (Fabaceae sobre o estrato arbustivo-arbóreo em áreas de Caatinga no Estado da Paraíba, Brasil = Impact of the invasion of Prosopis juliflora (Sw. DC. (Fabaceae in areas of Caatinga in the state of Paraíba, Brazil

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Leonaldo Alves de Andrade

2010-07-01

Full Text Available Estima-se que as áreas invadidas por algaroba – Prosopis juliflora (Sw. DC. (Fabaceae no semi-árido nordestino já ultrapassam um milhão de hectares. O presente trabalho objetivou estudar os impactos da invasão de P. juliflora sobre a fitodiversidade e a estrutura do componente arbustivo-arbóreo, em remanescentes de caatinga no Estado da Paraíba. Usando-se o método de parcelas, foram amostrados quatro ambientes, nos quais os indivíduos de todas as espécies arbustivas e arbóreas foram inventariados e medidos, estimando-se os parâmetros estruturais das comunidades. Também foi calculada a diversidade, pelo índice de Shannon-Wiener (H’ e o índice de impacto ambiental deexóticas (IIAE. No total, foram amostradas 19 famílias, 35 gêneros e 39 espécies. A invasora foi responsável por mais de 70% de toda a estrutura dos ambientes inventariados. A baixa diversidade e o elevado valor de impacto ambiental obtidos para os ambientes invadidosrevelaram, conjuntamente com os dados de estrutura das populações, os graves impactos que P. juliflora provoca nas comunidades invadidas. Evidencia-se com isso a formação de sistemas monodominados pela espécie invasora, o que revela a necessidade de controle efetivo de P. juliflora para se proteger o patrimônio genético autóctone.It is estimated that invader populations of algaroba Prosopis juliflora (Sw. DC. (Fabaceae in the northeastern semi-arid, Brazil, cover more than one million ha. This study aimed to study the impacts of P. juliflora invasion on phytodiversity and on the structure of the shrub-tree component in caatinga fragments in Paraiba state. Four environments were sampled by plots in which all shrubtree individuals were surveyed and measured, estimating structural parameters of thecommunities. Diversity was estimated by the Shannon-Wiener index (H', and the index of environmental impacts of exotic species (IIAE was also calculated. A total of 19 families, 35 genera and 39

Effects of Aqueous Extracts of Copaifera langsdorffii (Fabaceae) on the Growth and Reproduction of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae).

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Sâmia, R R; de Oliveira, R L; Moscardini, V F; Carvalho, G A

2016-10-01

Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is considered a pest of maize crops throughout the Western Hemisphere. We report on the effects of aqueous extracts of leaves and bark of Copaifera langsdorffii (Fabaceae) on the biology of S. frugiperda, as an alternative source of natural bioactive molecules for the sustainable management of this pest. Second instars were sprayed with aqueous extracts prepared with 5% (w/v) plant material and/or fed on an artificial diet containing extracts at a concentration equivalent to 0.25% (w/v) for 17 days. Both leaf and bark extracts of C. langsdorffii significantly reduced S. frugiperda food intake, feces, and larval weight and caused a delay in larval development. Additionally, C. langsdorffii-based extracts increased the oviposition period; induced morphological changes in the eggs, including deformation of the corium and malformation of the micropylar and aeropylar regions; and reduced egg viability. But, aqueous extracts of C. langsdorffii exhibited no negative effects on larval and pupal survival, duration of the pupal stage, survival of pupae, sex ratio, longevity, duration of pre-oviposition period, and female fecundity. Aqueous extracts of leaves and bark of C. langsdorffii are promising alternatives for the control of S. frugiperda in maize crops.

Selective fishing and analysis of xanthine oxidase binders from two Fabaceae species by coupling enzyme functionalized core-shell magnetic nanoparticles with HPLC-MS.

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Liu, Liangliang; Shi, Shuyun; Zhao, Huading; Yu, Jingang; Jiang, Xinyu; Chen, Xiaoqing

2014-01-15

Xanthine oxidase (XOD) immobilized core-shell magnetic silica (Fe3O4@SiO2-XOD) nanoparticles coupled with high performance liquid chromatography-mass spectrometry (HPLC-MS) was developed to fish out and analyze XOD binders from two Fabaceae species, Puerariae lobata flower and Glycyrrhiza uralensis root. The prepared Fe3O4@SiO2-XOD nanoparticles exhibited good specificity for XOD binders, better dispersion in aqueous solution and reusability than those of Fe3O4-XOD nanoparticles. The amount of XOD immobilized onto Fe3O4@SiO2 nanoparticles was 339.9μg/mg and the activity of Fe3O4@SiO2-XOD nanoparticles remained 95% after ten times usage. The optimum conditions of selective fishing were optimized, and finally incubating pH was set at 7, incubating temperature at 25°C and adsorption time at 30min. Twelve XOD binders were successfully identified from ethyl acetate extract of P. lobata flower and G. uralensis root. The developed method provides a rapid, purposeful and effective way to identify active compounds from natural complex mixtures. Copyright © 2013 Elsevier B.V. All rights reserved.

Reproductive phenology and sharing of floral resource among hummingbirds (Trochilidae) in inflorescences of Dahlstedtia pinnata (Benth.) Malme. (Fabaceae) in the Atlantic forest.

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Missagia, Caio C C; Verçoza, Fábio C; Alves, Maria Alice S

2014-12-01

The purpose of this study was to investigate the reproductive phenology and sharing of floral resource (nectar) of Dahlstedtia pinnata (Benth.) Malme. (Fabaceae), endemic of Atlantic forest, among hummingbirds. For the phenology, we looked at the presence of reproductive structures in the plants, and for floral resource sharing, the frequency of potential pollinators and foraging behaviors were examined. This study was conducted in Pedra Branca State Park, in state of Rio de Janeiro, in a dense ombrophilous forest, between August 2010 and August 2011. Flowering occurred between December 2010 and March 2011, and fruiting between April and June 2011. Hummingbirds' foraging schedules differed significantly, with legitimate visits to the flowers occurring in the morning and illegitimate visits occurring during late morning and the afternoon. Five species visited flowers, three of which were legitimate visitors: Phaethornis ruber, P. pretrei, and Ramphodon naevius. Amazilia fimbriata and Thalurania glaucopis females only visited illegitimately. Phaethornis ruber robbed nectar (78% of illegitimate visits, n=337). Ramphodon naevius, with a territorial foraging behavior and a body size bigger than that of other observed hummingbird species, dominated the floral visits, which suggests that D. pinnata is an important nourishing resource for this endemic bird of the Atlantic forest, currently globally categorized as Near Threatened.

Reproductive phenology and sharing of floral resource among hummingbirds (Trochilidae in inflorescences of Dahlstedtia pinnata (Benth. Malme. (Fabaceae in the Atlantic forest

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CAIO C.C. MISSAGIA

2014-12-01

Full Text Available The purpose of this study was to investigate the reproductive phenology and sharing of floral resource (nectar of Dahlstedtia pinnata (Benth. Malme. (Fabaceae, endemic of Atlantic forest, among hummingbirds. For the phenology, we looked at the presence of reproductive structures in the plants, and for floral resource sharing, the frequency of potential pollinators and foraging behaviors were examined. This study was conducted in Pedra Branca State Park, in state of Rio de Janeiro, in a dense ombrophilous forest, between August 2010 and August 2011. Flowering occurred between December 2010 and March 2011, and fruiting between April and June 2011. Hummingbirds' foraging schedules differed significantly, with legitimate visits to the flowers occurring in the morning and illegitimate visits occurring during late morning and the afternoon. Five species visited flowers, three of which were legitimate visitors: Phaethornis ruber, P. pretrei, and Ramphodon naevius. Amazilia fimbriata and Thalurania glaucopis females only visited illegitimately. Phaethornis ruber robbed nectar (78% of illegitimate visits, n=337. Ramphodon naevius, with a territorial foraging behavior and a body size bigger than that of other observed hummingbird species, dominated the floral visits, which suggests that D. pinnata is an important nourishing resource for this endemic bird of the Atlantic forest, currently globally categorized as Near Threatened.

Phytopatological monitoring of Inonotus rickii and GPS-GIS applications, Rome, Italy

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Moriondo M

2008-06-01

Full Text Available Plant disease management may be improved by collecting, storing, manipulating, analysing and displaying epidemiological information using a Geographic Information System (GIS, a useful tool to evaluate plant disease problems in a spatial context. In this study, GIS analysis was applied along with global positioning systems (GPS to integrate field data-collected with the spatial distribution of the pathogen Inonotus rickii. This pathogen provokes a decay of sapwood/heartwood and cankers, determining a progressive crown dieback and structural weakness of the trees, therefore increasing risk of branch breaks and tree failures. It is widespread in tropical and subtropical countries and it has already been recorded in many areas in Rome on Acer negundo, Albizia julibrissin, Koelreuteria paniculata, Celtis australis and Platanus x acerifolia. A survey was carried out in different boulevards of A. negundo and A. julibrissin with the aim of evaluating disease symptoms such as sparse foliage, dead twigs and branches, wood decay and presence of fungal structures. In this survey, I. rickii was recorded also on Robinia pseudoacacia, which is a new host. The study allowed to obtain thematic maps showing the spatial distribution of all infected trees, as well as the presence of anamorph and/or teleomorph structures of the fungus. Moreover, a map representing the incidence of the pathogen in different boulevards was obtained. The usefulness of GIS analysis in studies aimed to support and refine management strategies for disease control in urban trees is discussed.

Assessment of cadmium accumulation, toxicity, and tolerance in Brassicaceae and Fabaceae plants--implications for phytoremediation.

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Anjum, Naser A; Umar, Shahid; Iqbal, Muhammad

2014-09-01

This study, based on a greenhouse pot culture experiment conducted with 15-day-old rapeseed (Brassica campestris L. cv. Pusa Gold; family Brassicaceae) and moong bean (Vigna radiata L. Wilczek cv. Pusa Ratna; family Fabaceae) plants treated with cadmium (Cd) concentrations (0, 50, and 100 mg kg(-1) soil), investigates their potential for Cd accumulation and tolerance, and dissects the underlying basic physiological/biochemical mechanisms. In both species, plant dry mass decreased, while Cd concentration of both root and shoot increased with increase in soil Cd. Roots harbored a higher amount of Cd (vs. shoot) in B. campestris, while the reverse applied to V. radiata. By comparison, root Cd concentration was higher in B. campestris than in V. radiata. The high Cd concentrations in B. campestris roots and V. radiata shoots led to significant elevation in oxidative indices, as measured in terms of electrolyte leakage, H2O2 content, and lipid peroxidation. Both plants displayed differential adaptation strategies to counteract the Cd burden-caused anomalies in their roots and shoots. In B. campestris, increasing Cd burden led to a significantly decreased reduced glutathione (GSH) content but a significant increase in activities of GSH reductase (GR), GSH peroxidase (GPX), and GSH sulfotransferase (GST). However, in V. radiata, increasing Cd burden caused significant increase in GSH content and GR activity, but a significant decline in activities of GPX and GST. Cross talks on Cd burden of tissues and the adapted Cd tolerance strategies against Cd burden-accrued toxicity indicated that B. campestris and V. radiata are good Cd stabilizer and Cd extractor, respectively, wherein a fine tuning among the major components (GR, GPX, GST, GSH) of the GSH redox system helped the plants to counteract differentially the Cd load-induced anomalies in tissues. On the whole, the physiological/biochemical characterization of the B. campestris and V. radiata responses to varying Cd

Effects of the parasitism of Struthanthus flexicaulis (Mart. Mart. (Loranthaceae on the fitness of Mimosa calodendron Mart. (Fabaceae, an endemic shrub from rupestrian fields over ironstone outcrops, Minas Gerais State, Brazil Efeitos do parasitismo de Struthanthus flexicaulis (Mart. Mart. (Loranthaceae na aptidão de Mimosa calodendron Mart. (Fabaceae, um arbusto endêmico dos campos rupestres sobre canga, em Minas Gerais, Brasil

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Fabiana Alves Mourão

2009-09-01

Full Text Available Parasitic plants (mistletoes may alter the growth, reproduction and physiology of their hosts. Mimosa calodendron (Fabaceae is a legume abundant in rupestrian fields on ironstone outcrops, frequently attacked by the hemiparasite Struthanthus flexicaulis (Loranthaceae. The objective of this study was to evaluate the consequences of parasitism by S. flexicaulis on the fitness of M. calodendron. The intensity of parasitism and mortality on hosts of different sizes was evaluated, and foliage cover, fruit and seed set in parasitized and non-parasitized individuals were compared. More than 65% of a population of 1820 individuals was attacked. Host density positively influenced parasitism. The mortality and number of attacked hosts increased with their crown diameter. Heavily parasitized individuals showed 75 to 95% reduction of leaf cover and fruit production of 25% of those non-parasitized. Although no statistical difference was detected between the number of seeds per fruit, seed weight was lower in attacked plants. Parasitism by S. flexicaulis on M. calodendron may alter its population structure and dynamics, by reducing survival and fecundity rates.As plantas parasitas (ervas-de-passarinho podem alterar o crescimento, reprodução e fisiologia das hospedeiras. Mimosa calodendron (Fabaceae é uma leguminosa abundante nos campos rupestres sobre canga, freqüentemente atacada pela hemiparasita Struthanthus flexicaulis (Loranthaceae. O objetivo deste trabalho foi avaliar as conseqüências do parasitismo de S. flexicaulis na aptidão de M. calodendron. Foram avaliadas a intensidade de parasitismo e mortalidade em mimosas de diferentes tamanhos, e comparadas a cobertura foliar e a produção de frutos e sementes em indivíduos parasitados e não parasitados. Mais de 65% da população de 1.820 indivíduos estavam parasitados. A densidade de mimosas influenciou positivamente o parasitismo. As taxas de parasitismo e de mortalidade foram maiores nas

Gelatinous fibers and variant secondary growth related to stem undulation and contraction in a monkey ladder vine, Bauhinia glabra (Fabaceae).

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Fisher, Jack B; Blanco, Mario A

2014-04-01

Some of the most striking stem shapes occur in species of Bauhinia (Fabaceae) known as monkey ladder vines. Their mature stems are flattened and develop regular undulations. Although stems have variant (anomalous) secondary growth, the mechanism causing the undulations is unknown. We measured stem segments over time (20 mo), described stem development using light microscopy, and correlated the changes in stem shape with anatomy. Growing stems are initially straight and bear tendrils on short axillary branches. The inner secondary xylem has narrow vessels and lignified fibers. As stems age, they become flattened and increasingly undulated with the production of two lobes of outer secondary xylem (OX) with wide vessels and only gelatinous fibers (G-fibers). Similar G-fibers are present in the secondary phloem and the cortical sclerified layer. In transverse sections, the concave side of each undulation has a greater area and quantity of G-fibers than the opposite convex side. Some older stems are not undulated and have less lobing of OX. Undulation causes a shortening of the stem segments: up to 28% of the original length. Uneven distribution of G-fibers produces tensions that are involved in the protracted development of undulations. While young extending shoots attach by lateral branch tendrils, older stems may maintain their position in the canopy using undulations and persistent branch bases as gripping devices. Flattened and undulated stems with G-fibers produce flexible woody stems.

Biogeochemistry and biodiversity interact to govern N2 fixers (Fabaceae) across Amazon tropical forests

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Batterman, Sarah; Hedin, Lars; Lloyd, Jon; Quesada, Beto

2015-04-01

Dinitrogen (N2)-fixing trees in the Fabaceae fulfill a central role in tropical rainforests by supplying nitrogen from the atmosphere, yet whether they will support a forest CO2 sink in the future by alleviating nitrogen limitation may depend on whether and how they are controlled by local environmental conditions. Theory predicts that soil nutrients govern the function of N2 fixers, yet there have been no large-scale field-based tests of this idea. Moreover, recent findings indicate that N2-fixing species behave differently in biogeochemical cycles, suggesting that any environmental control may differ by species, and that the diversity of N2-fixing trees may be critical for ensuring tropical forest function. In this talk, we will use the RAINFOR dataset of 108 (~1.0 ha) lowland tropical rainforest plots from across the Amazon Basin to test whether the abundance and diversity of N2-fixing trees are controlled by soil nutrient availability (i.e., increasing with phosphorus and decreasing with nitrogen), or if fixer abundance and diversity simply follow the dynamics of all tree species. We also test an alternative - but not mutually exclusive - hypothesis that the governing factor for fixers is forest disturbance. Results show a surprising lack of control by local nutrients or disturbance on the abundance or diversity of N2 fixers. The dominant driver of fixer diversity was the total number of tree species, with fixers comprising 10% of all species in a forest plot (R2 = 0.75, linear regression). When considering the dominant taxa of N2 fixers (Inga, Swartzia, Tachigali) alone, environmental factors (nitrogen, phosphorus and disturbance) became important and clearly governed their abundance. These taxa, which contain >60% of N2-fixing trees in the data set, appear to have evolved to specialize in different local environmental conditions. The strong biogeochemistry-by-biodiversity interaction observed here points to a need to consider individual species or taxa of N2

Lack of divergence in seed ecology of two Amphicarpaea (Fabaceae) species disjunct between eastern Asia and eastern North America.

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Zhang, Keliang; Baskin, Jerry M; Baskin, Carol C; Yang, Xuejun; Huang, Zhenying

2015-06-01

Many congeneric species are disjunct between eastern Asia and eastern North America. No previous study has compared the seed biology of closely related disjunct taxa of legumes or of a diaspore-heteromorphic species. Our objective was to compare seed dormancy in two such sister species in the genus Amphicarpaea (Fabaceae). We investigated the ecology and ecophysiology of aerial and subterranean seeds of the amphicarpic species Amphicarpaea edgeworthii from China and compared the results to those published for its sister species A. bracteata from eastern North America. The seed coat of aerial seeds of A. edgeworthii is well developed, whereas the seed coat of subterranean seeds is not. Aerial seeds have combinational dormancy (physical dormancy [PY] + physiological dormancy [PD]) broken by scarification followed by cold stratification or by after-ripening and scarification; whereas subterranean seeds have PD broken by cold stratification. Aerial seeds formed a persistent soil seed bank, and subterranean seeds a transient soil seed bank. Aerial seeds of A. bracteata also have PY+PD and subterranean seeds PD. Subterranean seeds of both species are desiccation intolerant. Dormancy in neither aerial nor subterranean seeds of both species has diverged over geological time. Compared to subterranean seeds, aerial seeds of both species dispersed over longer distances. Seed dispersal ability and degree of dormancy of neither species fits the high-risk/low-risk (H-H/L-L) strategy found in many diaspore-dimorphic species. Rather, both species have an H-L/L-H strategy for these two life history traits. © 2015 Botanical Society of America, Inc.

Phylogeny, biogeography and character evolution in the tribe Desmodieae (Fabaceae: Papilionoideae), with special emphasis on the New Caledonian endemic genera.

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Jabbour, Florian; Gaudeul, Myriam; Lambourdière, Josie; Ramstein, Guillaume; Hassanin, Alexandre; Labat, Jean-Noël; Sarthou, Corinne

2018-01-01

The nearly cosmopolitan tribe Desmodieae (Fabaceae) includes many important genera for medicine and forage. However, the phylogenetic relationships among the infratribal groups circumscribed using morphological traits are still poorly known. In this study, we used chloroplast (rbcL, psbA-trnH) and nuclear (ITS-1) DNA sequences to investigate the molecular phylogeny and historical biogeography of Desmodieae, and infer ancestral states for several vegetative and reproductive traits. Three groups, corresponding to the Desmodium, Lespedeza, and Phyllodium groups sensu Ohashi were retrieved in the phylogenetic analyses. Conflicts in the topologies inferred from the chloroplast and nuclear datasets were detected. For instance, the Lespedeza clade was sister to the groups Phyllodium+Desmodium based on chloroplast DNA, but nested within the Desmodium group based on ITS-1. Moreover, the New Caledonian endemic genera Arthroclianthus and Nephrodesmus were not monophyletic but together formed a clade, which also included Hanslia and Ohwia based on chloroplast DNA. The hypothetical common ancestor of Desmodieae was dated to the Middle Oligocene (ca. 28.3Ma) and was likely an Asian shrub or tree producing indehiscent loments. Several colonization events towards Oceania, America, and Africa occurred (all less than ca. 17.5Ma), most probably through long distance dispersal. The fruits of Desmodieae repeatedly evolved from indehiscence to dehiscence. We also showed that indehiscent loments allow for more variability in the number of seeds per fruit than indehiscent legumes. Modularity seems here to allow variability in the number of ovules produced in a single ovary. Copyright © 2017 Elsevier Inc. All rights reserved.

Population Genetic Structure of Glycyrrhiza inflata B. (Fabaceae) Is Shaped by Habitat Fragmentation, Water Resources and Biological Characteristics.

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Yang, Lulu; Chen, Jianjun; Hu, Weiming; Yang, Tianshun; Zhang, Yanjun; Yukiyoshi, Tamura; Zhou, Yanyang; Wang, Ying

2016-01-01

Habitat fragmentation, water resources and biological characteristics are important factors that shape the genetic structure and geographical distribution of desert plants. Analysis of the relationships between these factors and population genetic variation should help to determine the evolutionary potential and conservation strategies for genetic resources for desert plant populations. As a traditional Chinese herb, Glycyrrhiza inflata B. (Fabaceae) is restricted to the fragmented desert habitat in China and has undergone a dramatic decline due to long-term over-excavation. Determining the genetic structure of the G. inflata population and identifying a core collection could help with the development of strategies to conserve this species. We investigated the genetic variation of 25 G. inflata populations based on microsatellite markers. A high level of population genetic divergence (FST = 0.257), population bottlenecks, reduced gene flow and moderate genetic variation (HE = 0.383) were detected. The genetic distances between the populations significantly correlated with the geographical distances, and this suggests that habitat fragmentation has driven a special genetic structure of G. inflata in China through isolation by distance. STRUCTURE analysis showed that G. inflata populations were structured into three clusters and that the populations belonged to multiple water systems, which suggests that water resources were related to the genetic structure of G. inflata. In addition, the biological characteristics of the perennial species G. inflata, such as its long-lived seeds, asexual reproduction, and oasis ecology, may be related to its resistance to habitat fragmentation. A core collection of G. inflata, that included 57 accessions was further identified, which captured the main allelic diversity of G. inflata. Recent habitat fragmentation has accelerated genetic divergence. The population genetic structure of G. inflata has been shaped by habitat

Current Status of the Systematics of Astragalus L. (Fabaceae with Special Reference to the Himalayan Species in India

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Lal Babu Chaudhary

2008-12-01

Full Text Available Astragalus is considered one of the most diverse genera in the family Leguminosae (nom. alt. Fabaceae. Although a large number of works have been carried out on the genus, no monograph is available except some regional accounts and revisions chiefly at sectional level. It may be due to the sheer size of the genus (ca. 3000 spp. and diverse nature, the genus is quite variable in habit and habitats, size of the plants, nature of indumentums, stipules, leaf rachis, types of inflorescence, relative length of petals, pods etc. Usually, genus is divided into eight to ten subgenera and more than 245 sections. In recently conducted molecular phylogenetic studies it has been shown that none of the subgenera and large sections are monophyletic. However, it has been clearly demonstrated that Astragalus is monophyletic except some outlier species. The chromosome numbers are also quite interesting and significant in Astragalus for its phylogenetic studies. There is a strong correlation between its geographic distribution and chromosome numbers. Currently about 80 species have been recorded from India chiefly from the Himalayas. Except some of our recent publications, not much studies have been carried out on the genus in India after 'The Flora of British India'. Astragalus is not of much economic importance, however, some of its species are well known for commercial gum tragacanth production especially in Iran and China. In India, A. candolleanus is a well known drug as ‘Rudanti’ or ‘Rudravanti’used for tuberculosis, skin diseases, coughs and blood purifier. The aim of this article is to review the entire work carried out on Astragalus and to bring out scattered information at one place for better understanding of the subject and to find out the future prospective of the research in India on the genus.

Seed colour affects light and temperature requirements during germination in two Lotus species (Fabaceae) of the Arabian subtropical deserts.

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Bhatt, Arvind; Gairola, Sanjay; El-Keblawy, Ali A

2016-06-01

Heterogeneity in seeds mostly occurs due to physiological, environmental and genetic factors, and these could affect seed dormancy and germination. Therefore, the aim of our study was to assess the effect of seed colour on germination behavior. For this, both light and temperature requirements were assessed in Lotus glinoides and Lotus halophilus (Fabaceae) from the hyper-arid deserts of the United Arab Emirates. Germination was assessed in terms of both final germination level (percentage) and germination rate, as expressed by Timson’s germination velocity index. Lotus glinoides produces black and yellow-colored seeds, and L. halophilus produces green and yellow seeds. Different seed lots were germinated in both light and darkness at different temperatures. Yellow seeds of the two species attained significantly lower germination, compared to black and green seeds. There was no specific light or temperature requirements for the germination of the two coloured seeds of L. glinoides; the effect of interactions between seed colour and both light and incubation temperature, were not significant on the final germination percentage. In L. halophilus, green seeds germinated significantly more in both light and darkness at lower temperatures (15/25 °C) and in light at higher temperatures (25/35 °C), compared to yellow seeds. Yellow seeds germinated faster, compared to black at 15/25 °C in L. glinoides and compared to green seeds at 15/25 °C and 25/35 °C in L. halophilus. Seed colour variation, at least in L. halophilus, could be a survival strategy that would determine the time of germination throughout the year in the unpredictable desert environment.

Hexavalent chromium-induced differential disruption of cortical microtubules in some Fabaceae species is correlated with acetylation of α-tubulin.

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Eleftheriou, Eleftherios P; Adamakis, Ioannis-Dimosthenis S; Michalopoulou, Vasiliki A

2016-03-01

The effects of hexavalent chromium [Cr(VI)] on the cortical microtubules (MTs) of five species of the Fabaceae family (Vicia faba, Pisum sativum, Vigna sinensis, Vigna angularis, and Medicago sativa) were investigated by confocal laser scanning microscopy after immunolocalization of total tubulin with conventional immunofluorescence techniques and of acetylated α-tubulin with the specific 6-11B-1 monoclonal antibody. Moreover, total α-tubulin and acetylated α-tubulin were quantified by Western immunoblotting and scanning densitometry. Results showed the universality of Cr(VI) detrimental effects to cortical MTs, which proved to be a sensitive and reliable subcellular marker for monitoring Cr(VI) toxicity in plant cells. However, a species-specific response was recorded, and a correlation of MT disturbance with the acetylation status of α-tubulin was demonstrated. In V. faba, MTs were depolymerized at the gain of cytoplasmic tubulin background and displayed low α-tubulin acetylation, while in P. sativum, V. sinensis, V. angularis, and M. sativa, MTs became bundled and changed orientation from perpendicular to oblique or longitudinal. Bundled MTs were highly acetylated as determined by both immunofluorescence and Western immunoblotting. Tubulin acetylation in P. sativum and M. sativa preceded MT bundling; in V. sinensis it followed MT derangement, while in V. angularis the two phenomena coincided. Total α-tubulin remained constant in all treatments. Should acetylation be an indicator of MT stabilization, it is deduced that bundled MTs became stabilized, lost their dynamic properties, and were rendered inactive. Results of this report allow the conclusion that Cr(VI) toxicity disrupts MTs and deranges the MT-mediated functions either by depolymerizing or stabilizing them.

Efecto de las arañas (Arachnida: Araneae como depredadoras de insectos plaga en cultivos de alfalfa (Medicago sativa (Fabaceae en Argentina

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Andrea Armendano

2011-12-01

Full Text Available Effect of spiders (Arachnida: Araneae as predators of insect pest in alfalfa crops (Medicago sativa (Fabaceae in Argentina. Spiders are predators that reduce insect pest populations in agroecosystems. Trials were conducted to measure the selectivity against different insect preys, the daily consumption, effect of predators alone and together with a known number of preys, and the indirect effect of predators on vegetation. For this, experimental units (1x1m were used covered with a fine plastic mesh. Misumenops pallidus, Oxyopes salticus and Araneus sp. were used as generalist predators, and aphids, weevils, locusts, chrysomelids and Lepidoptera larvae as their potential preys. Among the preys offered, the spiders preferred Lepidoptera larvae compared to the other two pests groups (weevils and aphids. The maximum consumption rate was of 93.33% for Lepidoptera larvae, 25.33% for aphids and 11.67% for weevils. The Q Index values for the three species of spiders showed a positive selectivity only for defoliating larvae. O. salticus showed the highest values of consumption rates while Rachiplusia nu was the most consumed. The maximum value of consumption in 24 hours was showed by O. salticus on R. nu (C=2.8. The association of several species of predatory spiders increased the total number of insects captured, and also showed that the addition of spiders caused a decrease in the number of leaves damaged by the effect of lepidopterous larvae. Rev. Biol. Trop. 59 (4: 1651-1662. Epub 2011 December 01

Aberration of mitosis by hexavalent chromium in some Fabaceae members is mediated by species-specific microtubule disruption.

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Eleftheriou, Eleftherios P; Michalopoulou, Vasiliki A; Adamakis, Ioannis-Dimosthenis S

2015-05-01

Because the detrimental effects of chromium (Cr) to higher plants have been poorly investigated, the present study was undertaken to verify the toxic attributes of hexavalent chromium [Cr(VI)] to plant mitotic microtubules (MTs), to determine any differential disruption of MTs during mitosis of taxonomically related species and to clarify the relationship between the visualized chromosomal aberrations and the Cr(VI)-induced MT disturbance. For this purpose, 5-day-old uniform seedlings of Vicia faba, Pisum sativum, Vigna sinensis and Vigna angularis, all belonging to the Fabaceae family, were exposed to 250 μM Cr(VI) supplied as potassium dichromate (K₂Cr₂O₇) for 24, 72 and 120 h and others in distilled water serving as controls. Root tip samples were processed for tubulin immunolabelling (for MT visualization) and DNA fluorescent staining (for chromosomal visualization). Microscopic preparations of cell squashes were then examined and photographed by confocal laser scanning microscopy (CLSM). Cr(VI) halted seedling growth turning roots brown and necrotic. Severe chromosomal abnormalities and differential disturbance of the corresponding MT arrays were found in all mitotic phases. In particular, in V. faba MTs were primarily depolymerized and replaced by atypical tubulin conformations, whereas in P. sativum, V. sinensis and V. angularis they became bundled in a time-dependent manner. In P. sativum, the effects were milder compared to those of the other species, but in all cases MT disturbance adversely affected the proper aggregation of chromosomes on the metaphase plate, their segregation at anaphase and organization of the new nuclei at telophase. Cr(VI) is very toxic to seedling growth. The particular effect depends on the exact stage the cell is found at the time of Cr(VI) entrance and is species-specific. Mitotic MT arrays are differentially deranged by Cr(VI) in the different species examined, even if they are taxonomically related, while their

Ecologie et gestion des espèces multi-usages du genre Erythrophleum (Fabaceae-Caesalpinioideae en Afrique (synthèse bibliographique

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Gorel, AP.

2015-01-01

Full Text Available Ecology and management of the multipurpose Erythrophleum species (Fabaceae-Caesalpinioideae in Africa. A review. Introduction. Widespread in Africa, the Erythrophleum genus includes four tropical tree species with a high economic and socio-cultural value: Erythrophleum ivorense, Erythrophleum suaveolens, Erythrophleum africanum and Erythrophleum lasianthum. Appropriate knowledge of the ecology and the distribution of these species is required for their sustainable management. This paper is based on an extensive literature review and summarizes the available information on the African Erythrophleum species in terms of botany, phylogeography, ecology, forestry and ethnobotany. Literature. Erythrophleum ivorense, E. suaveolens, E. africanum and E. lasianthum are morphologically different and occur in distinct climatic areas. They are non-pioneer light demander (E. ivorense and E. suaveolens or pioneer species (E. africanum. Their primary mode of dispersal is via ballochore. The seeds have a dormancy period and can remain in the soil for several years. Their reproductive and foliar phenologies are regular and annual. Growth rate varies between species, ranging from 0.65 cm per year for E. ivorense to 0.16 cm per year for E. africanum. These trees are used in traditional medicine. Only E. ivorense and E. suaveolens (Tali are mainly logged for timber. Conclusions. Erythrophleum species ecological data are better informed for E. ivorense and E. suaveolens because of their economic importance. This review highlights the existing lack of knowledge regarding the phenology (effects of climate, fructification periods, the minimum diameter of fructification and the mechanisms of natural seed dormancy breakage. Targeting such weaknesses is required to create or re-evaluate methods of conservation and/or enhancement of populations and logging practices.

Phylogeography of the Tree Hymenaea stigonocarpa (Fabaceae: Caesalpinioideae) and the Influence of Quaternary Climate Changes in the Brazilian Cerrado

Science.gov (United States)

Ramos, Ana Carolina Simões; Lemos-Filho, José Pires; Ribeiro, Renata Acácio; Santos, Fabrício Rodrigues; Lovato, Maria Bernadete

2007-01-01

Background and Aims Hymenaea stigonocarpa (Fabaceae: Caesalpinioideae) is an endemic tree from the Brazilian cerrado (savanna vegetation), a biome classified as a hotspot for conservation priority. This study investigates the phylogeographic structure of H. stigonocarpa, in order to understand the processes that have led to its current spatial genetic pattern. Methods The polymorphism level and spatial distribution of variants of the plastid non-coding region between the genes psbC and trnS were investigated in 175 individuals from 17 populations, covering the greater part of the total distribution of the species. Molecular diversity indices were calculated and intra-specific relationships were inferred by the construction of haplotype networks using the median-joining method. Genetic differentiation among populations and main geographical groups was evaluated using spatial analysis of molecular variance (SAMOVA). Key Results Twenty-three different haplotypes were identified. The level of differentiation among the populations analysed was relatively high (FST = 0·692). Phylogeographic analyses showed a clear association between the haplotype network and geographic distribution of populations, revealing three main geographical groups: western, central and eastern. SAMOVA corroborated this finding, indicating that most of the variation can be attributed to differences among these three groups (58·8 %), with little difference among populations within groups (FSC = 0·252). Conclusions The subdivision of the geographic distribution of H. stigonocarpa populations into three genetically differentiated groups can be associated with Quaternary climatic changes. The data suggest that during glacial times H. stigonocarpa populations became extinct in most parts of the southern present-day cerrado area. Milder climatic conditions in the north and eastern portions of the cerrado resulted in maintenance of populations in these regions. Thus it is inferred that the most

Use of Strategic Placement of Dredged Sediments to Support Horseshoe Island in the Atchafalaya River, Louisiana: A Preliminary Ecological Survey

Science.gov (United States)

2014-08-01

cowpea (Vigna luteola), broadleaf cattail (Typha latifolia), invasive Chinese tallowtree (Triadica sebifera), rosemallow (Hibiscus lasiocarpos), and...Benth. hairypod cowpea Fabaceae N Vigna unguiculata (L.) Walp. cowpea Fabaceae - Hydrilla verticillata (L. f.) Royle waterthyme Hydrocharitaceae I

The influence of land use on soil organic carbon and nitrogen content and redox potential

DEFF Research Database (Denmark)

Kusliene, Gedrime

2010-01-01

different farming systems (conventional and organic) as well as abandoned lands. We choose the plants of two botanical species (Poaceae and Fabaceae) in organic and conventional farming systems as well as abandoned lands. Experimental results show that the best soil organic matter status according...... to the investigated indexes is in the soils of conventional and orgaic farming systems occupied with mixtures of Poaceae and Fabaceae and the worst - in the soils of abandoned Poaceae meadowa. In the abandoned lands, Fabaceae (galega) had better influence on soil organic matter status than Poaceae....

2430-IJBCS-Article-Kouakou Theodore Kouadio+

African Journals Online (AJOL)

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Euphorbiaceae. 1. 2. Deeringiana pruerens. Fabaceae. 1. 1. Dioscorea alata. Dioscoreaceae. 6. 56. Dioscorea cayenensis-rotundata. Dioscoreaceae. 5. 11. Glycine max. Fabaceae. 2. 16. Ipomea batatas. Convolvulaceae. 1. 10. Justicia tenela. Acanthaceae. 1. 1. Lactuca sativa. Asteraceae. 2. 11. Lycopersicon esculentum.

Impactos da invasão de Prosopis juliflora (sw. DC. (Fabaceae sobre o estrato arbustivo-arbóreo em áreas de Caatinga no Estado da Paraíba, Brasil - doi: 10.4025/actascibiolsci.v32i3.4535 Impact of the invasion of Prosopis juliflora (Sw. DC. (Fabaceae in areas of Caatinga in the state of Paraiba, Brazil - doi: 10.4025/actascibiolsci.v32i3.4535

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Juliano Ricardo Fabricante

2010-09-01

Full Text Available Estima-se que as áreas invadidas por algaroba – Prosopis juliflora (Sw. DC. (Fabaceae no semi-árido nordestino já ultrapassam um milhão de hectares. O presente trabalho objetivou estudar os impactos da invasão de P. juliflora sobre a fitodiversidade e a estrutura do componente arbustivo-arbóreo, em remanescentes de caatinga no Estado da Paraíba. Usando-se o método de parcelas, foram amostrados quatro ambientes, nos quais os indivíduos de todas as espécies arbustivas e arbóreas foram inventariados e medidos, estimando-se os parâmetros estruturais das comunidades. Também foi calculada a diversidade, pelo índice de Shannon-Wiener (H’ e o índice de impacto ambiental de exóticas (IIAE. No total, foram amostradas 19 famílias, 35 gêneros e 39 espécies. A invasora foi responsável por mais de 70% de toda a estrutura dos ambientes inventariados. A baixa diversidade e o elevado valor de impacto ambiental obtidos para os ambientes invadidos revelaram, conjuntamente com os dados de estrutura das populações, os graves impactos que P. juliflora provoca nas comunidades invadidas. Evidencia-se com isso a formação de sistemas monodominados pela espécie invasora, o que revela a necessidade de controle efetivo de P. juliflora para se proteger o patrimônio genético autóctone.It is estimated that invader populations of algaroba Prosopis juliflora (Sw. DC. (Fabaceae in the northeastern semi-arid, Brazil, cover more than one million ha. This study aimed to study the impacts of P. juliflora invasion on phytodiversity and on the structure of the shrub-tree component in caatinga fragments in Paraiba state. Four environments were sampled by plots in which all shrub-tree individuals were surveyed and measured, estimating structural parameters of the communities. Diversity was estimated by the Shannon-Wiener index (H', and the index of environmental impacts of exotic species (IIAE was also calculated. A total of 19 families, 35 genera and 39

Observations préliminaires de la variabilité entre quelques morphotypes de voandzou (Vigna subterranea L. Verdc., Fabaceae de Côte d'Ivoire

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Zoro Bi IA.

2005-01-01

Full Text Available Preliminary observations of variability between some morphotypes of bambara groundnut (Vigna subterranea L. Verdc., Fabaceae from Côte d’Ivoire. Bambara groundnut (Vigna subterranea L. Verdc., is a food legume mainly cultivated by women for whom it represents a source of income for the household. In Côte d’Ivoire, the cultivation of bambara groundnut is located in the western and northern parts of the country. These zones are characterised by contrasted agroecology including tropical rain forest and dry savanna. In these zones, bambara groundnut plays a key role in both food and culture of peoples. Four morphotypes of Côte d’Ivoire (ICU, BPR, RBU, NFU were used in a preliminary study to assess the phenotypic variability between morphotypes. For each morphotype, 100 individuals were sampled to analyse 26 agromorphological traits selected from the list of bambara groundnut descriptors. Results of statistical analyses showed an important variability among morphotypes suggesting that 22 of these characters could be powerful to distinguish diversity among bambara groundnut morphotypes of Côte d’Ivoire. Three morphotypes (ICU, BPR and RBU show a shorter reproductive cycle than the other (NFU. In our experimental conditions, morphotypes with a shorter reproductive cycle give a higher percentage of matured pods (87 to 95%, compared to morphotype NFU (60%. The morphotype ICU was particularly earlier, maturing 90 days after sowing (DAS, whereas the long reproductive cycle morphotype (NFU required about 137 days. Based on the analysed agronomic traits, possibilities to improve bambara groundnut yield and to promote its cultivation in Côte d’Ivoire are discussed.

Phylogeny of palaeotropic Derris-like taxa (Fabaceae) based on chloroplast and nuclear DNA sequences shows reorganization of (infra)generic classifications is needed.

Science.gov (United States)

Sirichamorn, Yotsawate; Adema, Frits A C B; Gravendeel, Barbara; van Welzen, Peter C

2012-11-01

Palaeotropic Derris-like taxa (family Fabaceae, tribe Millettieae) comprise 6-9 genera. They are well known as important sources of rotenone toxin, which are used as organic insecticide and fish poison. However, their phylogenetic relationships and classification are still problematic due to insufficient sampling and high morphological variability. Fifty species of palaeotropic Derris-like taxa were sampled, which is more than in former studies. Three chloroplast genes (trnK-matK, trnL-F IGS, and psbA-trnH IGS) and nuclear ribosomal ITS /5.8S were analyzed using parsimony and Bayesian methods. Parsimony and Bayesian analyses of individual and combined markers show more or less similar tree topologies (only varying in terminal branches). The old-world monophyletic genera Aganope, Brachypterum, and Leptoderris are distinct from Derris s.s., and their generic status is here confirmed. Aganope may be classified into two or three subgeneric taxa. Paraderris has to be included in Derris s.s. to form a monophyletic group. The genera Philenoptera, Deguelia, and Lonchocarpus are monophyletic and distinct from each other and clearly separate from Derris s.s. Morphologically highly similar species of Derris s.s. are shown to be unrelated. Our study shows that previous infrageneric classifications of Derris are incorrect. Paraderris elliptica may contain several cryptic lineages that need further investigation. The concept of the genus Derris s.s. should be reorganized with a new generic circumscription by including Paraderris but excluding Brachypterum. Synapomorphic morphological features will be examined in future studies, and the status of the newly defined Derris and its closely related taxa will be formalized.

Pollen analysis of honey and pollen collected by Apis mellifera linnaeus, 1758 (Hymenoptera, Apidae), in a mixed environment of Eucalyptus plantation and native cerrado in Southeastern Brazil.

Science.gov (United States)

Simeão, C M G; Silveira, F A; Sampaio, I B M; Bastos, E M A F

2015-11-01

Eucalyptus plantations are frequently used for the establishment of bee yards. This study was carried on at Fazenda Brejão, northwestern region of the State of Minas Gerais, Brazil. This farm is covered both with native Cerrado vegetation (Brazilian savanna) and eucalyptus plantations. This paper reports on the botanic origin of pollen pellets and honey collected from honeybee (Apis mellifera) hives along a thirteen-month period (January 2004 to January 2005). The most frequent pollen types found in the pollen pellets during the rainy season were Trema micrantha (Ulmaceae), Copaifera langsdorffii (Fabaceae), an unidentified Poaceae, unidentified Asteraceae-2, Cecropia sp. 1 (Cecropiaceae) and Eucalyptus spp. (Myrtaceae); during the dry season the most frequent pollen types were Acosmium dasycarpum (Fabaceae), Cecropia sp. 1 (Cecropiaceae) and Eucalyptus spp. (Myrtaceae). Pollen grains of Baccharis sp. (Asteraceae), Cecropia sp. 1 (Cecropiaceae), Copaifera langsdorffii (Fabaceae), Mimosa nuda (Fabaceae), Eucalyptus spp. (Myrtaceae) and Trema micrantha (Ulmaceae) were present in the honey samples throughout the study period.

Pollen analysis of honey and pollen collected by Apis mellifera linnaeus, 1758 (Hymenoptera, Apidae, in a mixed environment of Eucalyptus plantation and native cerrado in Southeastern Brazil

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C. M. G. Simeão

Full Text Available Abstract Eucalyptus plantations are frequently used for the establishment of bee yards. This study was carried on at Fazenda Brejão, northwestern region of the State of Minas Gerais, Brazil. This farm is covered both with native Cerrado vegetation (Brazilian savanna and eucalyptus plantations. This paper reports on the botanic origin of pollen pellets and honey collected from honeybee (Apis mellifera hives along a thirteen-month period (January 2004 to January 2005. The most frequent pollen types found in the pollen pellets during the rainy season were Trema micrantha (Ulmaceae, Copaifera langsdorffii (Fabaceae, an unidentified Poaceae, unidentified Asteraceae-2, Cecropia sp. 1 (Cecropiaceae and Eucalyptus spp. (Myrtaceae; during the dry season the most frequent pollen types were Acosmium dasycarpum (Fabaceae, Cecropia sp. 1 (Cecropiaceae and Eucalyptus spp. (Myrtaceae. Pollen grains of Baccharis sp. (Asteraceae, Cecropia sp. 1 (Cecropiaceae, Copaifera langsdorffii (Fabaceae, Mimosa nuda (Fabaceae, Eucalyptus spp. (Myrtaceae and Trema micrantha (Ulmaceae were present in the honey samples throughout the study period.

Biomimetic FAA-certifiable, artificial muscle structures for commercial aircraft wings

Science.gov (United States)

Barrett, Ronald M.; Barrett, Cassandra M.

2014-07-01

This paper is centered on a new form of adaptive material which functions much in the same way as skeletal muscle tissue, is structurally modeled on plant actuator cells and capable of rapidly expanding or shrinking by as much as an order of magnitude in prescribed directions. Rapid changes of plant cell shape and sizes are often initiated via ion-transport driven fluid migration and resulting turgor pressure variation. Certain plant cellular structures like those in Mimosa pudica (sensitive plant), Albizia julibrissin (Mimosa tree), or Dionaea muscipula (Venus Flytrap) all exhibit actuation physiology which employs such turgor pressure manipulation. The paper begins with dynamic micrographs of a sectioned basal articulation joint from A. julibrissin. These figures show large cellular dimensional changes as the structure undergoes foliage articulation. By mimicking such structures in aircraft flight control mechanisms, extremely lightweight pneumatic control surface actuators can be designed. This paper shows several fundamental layouts of such surfaces with actuator elements made exclusively from FAA-certifiable materials, summarizes their structural mechanics and shows actuator power and energy densities that are higher than nearly all classes of conventional adaptive materials available today. A sample flap structure is shown to possess the ability to change its shape and structural stiffness as its cell pressures are manipulated, which in turn changes the surface lift-curve slope when exposed to airflows. Because the structural stiffness can be altered, it is also shown that the commanded section lift-curve slope can be similarly controlled between 1.2 and 6.2 rad-1. Several aircraft weight reduction principles are also shown to come into play as the need to concentrate loads to pass through point actuators is eliminated. The paper concludes with a summary of interrelated performance and airframe-level improvements including enhanced gust rejection, load

Biomimetic FAA-certifiable, artificial muscle structures for commercial aircraft wings

International Nuclear Information System (INIS)

Barrett, Ronald M; Barrett, Cassandra M

2014-01-01

This paper is centered on a new form of adaptive material which functions much in the same way as skeletal muscle tissue, is structurally modeled on plant actuator cells and capable of rapidly expanding or shrinking by as much as an order of magnitude in prescribed directions. Rapid changes of plant cell shape and sizes are often initiated via ion-transport driven fluid migration and resulting turgor pressure variation. Certain plant cellular structures like those in Mimosa pudica (sensitive plant), Albizia julibrissin (Mimosa tree), or Dionaea muscipula (Venus Flytrap) all exhibit actuation physiology which employs such turgor pressure manipulation. The paper begins with dynamic micrographs of a sectioned basal articulation joint from A. julibrissin. These figures show large cellular dimensional changes as the structure undergoes foliage articulation. By mimicking such structures in aircraft flight control mechanisms, extremely lightweight pneumatic control surface actuators can be designed. This paper shows several fundamental layouts of such surfaces with actuator elements made exclusively from FAA-certifiable materials, summarizes their structural mechanics and shows actuator power and energy densities that are higher than nearly all classes of conventional adaptive materials available today. A sample flap structure is shown to possess the ability to change its shape and structural stiffness as its cell pressures are manipulated, which in turn changes the surface lift-curve slope when exposed to airflows. Because the structural stiffness can be altered, it is also shown that the commanded section lift-curve slope can be similarly controlled between 1.2 and 6.2 rad −1 . Several aircraft weight reduction principles are also shown to come into play as the need to concentrate loads to pass through point actuators is eliminated. The paper concludes with a summary of interrelated performance and airframe-level improvements including enhanced gust rejection, load

Antihypertensive activity of 80% methanol seed extract of Calpurnia aurea (Ait.) Benth. subsp. aurea (Fabaceae) is mediated through calcium antagonism induced vasodilation.

Science.gov (United States)

Getiye, Yohannes; Tolessa, Tesfaye; Engidawork, Ephrem

2016-08-02

Calpurnia aurea (Ait.) Benth. subsp. aurea (CASA) (Fabaceae) seeds are used to treat hypertension in Ethiopian folklore medicine, particularly by Shinasha, Agew-awi and Amhara people in northwest Ethiopia. However, the claim has so far not been substantiated scientifically. The study was conducted to evaluate the antihypertensive activity of 80% methanol extract of CASA in animal model of hypertension as well as its vasorelaxant effect and possible underlying mechanisms in isolated guinea pig aorta. Hypotensive and antihypertensive effect of CASA extract was determined in vivo through the intravenous (iv) route in normotensive and hypertensive anesthetized rats using 2-kidney-1-clip (2K1C) rat model. Ex vivo, guinea pig thoracic aortic rings were isolated and suspended in organ bath, and the vasodepressor effects as well as the mechanism of action of the extract were studied by means of isometric tension recording experiments. The blood pressure fell dose-dependently and significantly in renal hypertensive and normotensive rats following i.v. administration, suggesting that the hydroalcoholic extract possesses hypotensive and antihypertensive effects. The extract also caused a dose-dependent relaxation of aorta pre-contracted with KCl at a concentration of 5-250mg/L, with a maximum relaxation of 92.1% achieved at 250mg/L. The relaxation mechanism was found to be independent of the muscarinic receptors, histamine receptors, ATP dependent K(+) channels, cyclooxygenase enzymes, cGMP/NO pathway and the endothelium system. The extract caused rightward shift of the Ca(++) dose-response curves, similar to that caused by verapamil, indicating that it produced vasorelaxation by inhibiting extracellular Ca(2+) influx. The findings demonstrate that the plant is endowed with antihypertensive effect, providing evidence for its traditional use. The effect may be, at least in part, due to dilation of blood vessels through blockage of Ca(2+) channels. Copyright © 2016 Elsevier

Humidity-regulated dormancy onset in the Fabaceae: a conceptual model and its ecological implications for the Australian wattle Acacia saligna

Science.gov (United States)

Tozer, Mark G.; Ooi, Mark K. J.

2014-01-01

Background and aims Seed dormancy enhances fitness by preventing seeds from germinating when the probability of seedling survival and recruitment is low. The onset of physical dormancy is sensitive to humidity during ripening; however, the implications of this mechanism for seed bank dynamics have not been quantified. This study proposes a model that describes how humidity-regulated dormancy onset may control the accumulation of a dormant seed bank, and seed experiments are conducted to calibrate the model for an Australian Fabaceae, Acacia saligna. The model is used to investigate the impact of climate on seed dormancy and to forecast the ecological implications of human-induced climate change. Methods The relationship between relative humidity and dormancy onset was quantified under laboratory conditions by exposing freshly matured non-dormant seeds to constant humidity levels for fixed durations. The model was field-calibrated by measuring the response of seeds exposed to naturally fluctuating humidity. The model was applied to 3-hourly records of humidity spanning the period 1972–2007 in order to estimate both temporal variability in dormancy and spatial variability attributable to climatic differences among populations. Climate change models were used to project future changes in dormancy onset. Key Results A sigmoidal relationship exists between dormancy and humidity under both laboratory and field conditions. Seeds ripened under field conditions became dormant following very short exposure to low humidity (<20 %). Prolonged exposure at higher humidity did not increase dormancy significantly. It is predicted that populations growing in a temperate climate produce 33–55 % fewer dormant seeds than those in a Mediterranean climate; however, dormancy in temperate populations is predicted to increase as a result of climate change. Conclusions Humidity-regulated dormancy onset may explain observed variation in physical dormancy. The model offers a systematic

ST proteins, a new family of plant tandem repeat proteins with a DUF2775 domain mainly found in Fabaceae and Asteraceae.

Science.gov (United States)

Albornos, Lucía; Martín, Ignacio; Iglesias, Rebeca; Jiménez, Teresa; Labrador, Emilia; Dopico, Berta

2012-11-07

Many proteins with tandem repeats in their sequence have been described and classified according to the length of the repeats: I) Repeats of short oligopeptides (from 2 to 20 amino acids), including structural cell wall proteins and arabinogalactan proteins. II) Repeats that range in length from 20 to 40 residues, including proteins with a well-established three-dimensional structure often involved in mediating protein-protein interactions. (III) Longer repeats in the order of 100 amino acids that constitute structurally and functionally independent units. Here we analyse ShooT specific (ST) proteins, a family of proteins with tandem repeats of unknown function that were first found in Leguminosae, and their possible similarities to other proteins with tandem repeats. ST protein sequences were only found in dicotyledonous plants, limited to several plant families, mainly the Fabaceae and the Asteraceae. ST mRNAs accumulate mainly in the roots and under biotic interactions. Most ST proteins have one or several Domain(s) of Unknown Function 2775 (DUF2775). All deduced ST proteins have a signal peptide, indicating that these proteins enter the secretory pathway, and the mature proteins have tandem repeat oligopeptides that share a hexapeptide (E/D)FEPRP followed by 4 partially conserved amino acids, which could determine a putative N-glycosylation signal, and a fully conserved tyrosine. In a phylogenetic tree, the sequences clade according to taxonomic group. A possible involvement in symbiosis and abiotic stress as well as in plant cell elongation is suggested, although different STs could play different roles in plant development. We describe a new family of proteins called ST whose presence is limited to the plant kingdom, specifically to a few families of dicotyledonous plants. They present 20 to 40 amino acid tandem repeat sequences with different characteristics (signal peptide, DUF2775 domain, conservative repeat regions) from the described group of 20 to 40

The inhibitory potential of the condensed-tannin-rich fraction of Plathymenia reticulata Benth. (Fabaceae) against Bothrops atrox envenomation.

Science.gov (United States)

de Moura, Valéria Mourão; da Silva, Wania Cristina Rodrigues; Raposo, Juliana D A; Freitas-de-Sousa, Luciana A; Dos-Santos, Maria Cristina; de Oliveira, Ricardo Bezerra; Veras Mourão, Rosa Helena

2016-05-13

Ethnobotanical studies have shown that Plathymenia reticulata Benth. (Fabaceae) has been widely used in cases of snake envenomation, particularly in Northern Brazil. In light of this, the aim of this study was to evaluate the inhibitory potential of the condensed-tannin-rich fraction obtained from the bark of P. reticulata against the main biological activities induced by Bothrops atrox venom (BaV). The chemical composition of the aqueous extract of P. reticulata (AEPr) was first investigated by thin-layer chromatography (TLC) and the extract was then fractionated by column chromatography on Sephadex LH-20. This yielded five main fractions (Pr1, Pr2, Pr3, Pr4 and Pr5), which were analyzed by colorimetry to determine their concentrations of total phenolics, total tannins and condensed tannins and to assess their potential for blocking the phospholipase activity of BaV. The Pr5 fraction was defined as the fraction rich in condensed tannins (CTPr), and its inhibitory potential against the activities of the venom was evaluated. CTPr was evaluated in different in vivo and in vitro experimental protocols. The in vivo protocols consisted of (1) pre-incubation (venom:CTPr, w/w), (2) pre-treatment (orally administered) and (3) post-treatment (orally administered) to evaluate the effect on the hemorrhagic and edematogenic activities of BaV; in the in vitro protocol the effect on phospholipase and coagulant activity using pre-incubation in both tests was evaluated. There was statistically significant inhibition (p<0.05) of hemorrhagic activity by CTPr when the pre-incubation protocol was used [55% (1:5, w/w) and 74% (1:10, w/w)] and when pre-treatment with doses of 50 and 100mg/kg was used (19% and 13%, respectively). However, for the concentrations tested, there was no statistically significant inhibition in the group subjected to post-treatment administered orally. CTPr blocked 100% of phospholipase activity and 63.3% (1:10, w/w) of coagulant activity when it was pre

Novelties in secretory structures and anatomy of Rhynchosia (Fabaceae).

Science.gov (United States)

De Vargas, Wanderleia; Sartori, Ângela L B; Dias, Edna S

2015-03-01

A comparative anatomical study was carried out on the secretory structures of leaflets from taxa belonging to the genus Rhynchosia - taxa difficult to delimit because of uncertain interspecific relations - in order to evaluate the potential diagnostic value of these anatomical traits for taxonomic assignment. A further objective was to establish consensual denomination for these secretory structures. The new anatomical features found in these taxa were sufficiently consistent to separate the species evaluated. The presence and localization of glandular-punctate structures bulbous-based trichomes, the number of layers in the palisade parenchyma and the arrangement of vascular units distinguish the taxa investigated and these characteristics can be extended to other species of Papilionoideae. The trichomes analyzed were described and classified into five types. Depicted in diagrams, photomicrographs, and by scanning electron microscopy, and listed for the first time at the genus and species levels. The information obtained served to effectively distinguish the taxa investigated among species of Papilonoideae.

Humidity-regulated dormancy onset in the Fabaceae: a conceptual model and its ecological implications for the Australian wattle Acacia saligna.

Science.gov (United States)

Tozer, Mark G; Ooi, Mark K J

2014-09-01

Seed dormancy enhances fitness by preventing seeds from germinating when the probability of seedling survival and recruitment is low. The onset of physical dormancy is sensitive to humidity during ripening; however, the implications of this mechanism for seed bank dynamics have not been quantified. This study proposes a model that describes how humidity-regulated dormancy onset may control the accumulation of a dormant seed bank, and seed experiments are conducted to calibrate the model for an Australian Fabaceae, Acacia saligna. The model is used to investigate the impact of climate on seed dormancy and to forecast the ecological implications of human-induced climate change. The relationship between relative humidity and dormancy onset was quantified under laboratory conditions by exposing freshly matured non-dormant seeds to constant humidity levels for fixed durations. The model was field-calibrated by measuring the response of seeds exposed to naturally fluctuating humidity. The model was applied to 3-hourly records of humidity spanning the period 1972-2007 in order to estimate both temporal variability in dormancy and spatial variability attributable to climatic differences among populations. Climate change models were used to project future changes in dormancy onset. A sigmoidal relationship exists between dormancy and humidity under both laboratory and field conditions. Seeds ripened under field conditions became dormant following very short exposure to low humidity (humidity did not increase dormancy significantly. It is predicted that populations growing in a temperate climate produce 33-55 % fewer dormant seeds than those in a Mediterranean climate; however, dormancy in temperate populations is predicted to increase as a result of climate change. Humidity-regulated dormancy onset may explain observed variation in physical dormancy. The model offers a systematic approach to modelling this variation in population studies. Forecast changes in climate have

First report of Maconellicoccus hirsutus (Green, 1908) (Hemiptera: Coccoidea: Pseudococcidae) and the associated parasitoid Anagyrus kamali Moursi, 1948 (Hymenoptera: Encyrtidae), in Brazil.

Science.gov (United States)

Marsaro Júnior, A L; Peronti, A L B G; Penteado-Dias, A M; Morais, E G F; Pereira, P R V S

2013-05-01

The pink hibiscus mealybug (PHM), Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae) and the associated hymenopterous parasitoid, Anagyrus kamali Moursi, 1948 (Hymenoptera: Encyrtidae), are reported for the first time in Brazil. Specimens of the PHM were collected on nine hosts plants, Annona muricata L. (Anonnaceae), Glycine max (L.) Merr. (Fabaceae), Centrolobium paraensis Tul. (Fabaceae), Inga edulis Mart. (Fabaceae), Hibiscus rosa-sinensis L. (Malvaceae), Psidium guajava L. (Myrtaceae), Averrhoa carambola L. (Oxalidaceae), Citrus sinensis (L.) Osbeck (Rutaceae) and Solanum lycopersicum L. (Solanaceae), in four municipalities in the north-northeast of the state of Roraima. The plants C. paraensis, I. edulis and C. sinensis are recorded for the first time as a hosts for PHM. Characteristic injuries observed on the host plants infested by PHM and suggestions for its management are presented.

Electron/electron acoustic instability

International Nuclear Information System (INIS)

Gary, S.P.

1987-01-01

The electron acoustic wave becomes a normal mode of an unmagnetized collisionless plasma in the presence of two electron components with similar densities, but strongly disparate temperatures. The characteristic frequency of this mode is the plasma frequency of the cooler electron component. If these two electron components have a relative drift speed several times the thermal speed of the cooler component, the electron/electron acoustic instability may arise. This paper describes the parametric dependences of the threshold drift speed and maximum growth rate of this instability, and compares these with the same properties of the electron/ion acoustic instability. Under the condition of zero current, the electron/ion acoustic instability typically has the lower threshold drift speed, so that observation of the electron/electron acoustic instability is a strong indication of the presence of an electrical current in the plasma

Effect of Leaves of Caesalpinia decapetala on Oxidative Stability of Oil-in-Water Emulsions

Directory of Open Access Journals (Sweden)

María Gabriela Gallego

2017-03-01

Full Text Available Caesalpinia decapetala (Roth Alston (Fabaceae (CD is used in folk medicine to prevent colds and treat bronchitis. This plant has antitumor and antioxidant activity. The antioxidant effects of an extract from Caesalpinia decapetala (Fabaceae were assessed by storage of model food oil-in-water emulsions with analysis of primary and secondary oxidation products. The antioxidant capacity of the plant extract was evaluated by the diphenylpicrylhydrazyl (DPPH, Trolox equivalent antioxidant capacity (TEAC, oxygen radical absorbance capacity (ORAC and ferric reducing antioxidant power (FRAP assays and by electron paramagnetic resonance (EPR spectroscopy. Lyophilized extracts of CD were added at concentrations of 0.002%, 0.02% and 0.2% into oil-in-water emulsions, which were stored for 30 days at 33 ± 1 °C, and then, oxidative stability was evaluated. The CD extract had high antioxidant activity (700 ± 70 µmol Trolox/g dry plant for the ORAC assay, mainly due to its phenolic components: gallic acid, quercetin, catechin, 4-hydroxybenzoic acid and p-coumaric acid. At a concentration of 0.2%, the extract significantly reduced the oxidative deterioration of oil-in-water emulsions. The results of the present study show the possibility of utilizing CD as a promising source of natural antioxidants for retarding lipid oxidation in the food and cosmetic industries.

Electronics and electronic systems

CERN Document Server

Olsen, George H

1987-01-01

Electronics and Electronic Systems explores the significant developments in the field of electronics and electronic devices. This book is organized into three parts encompassing 11 chapters that discuss the fundamental circuit theory and the principles of analog and digital electronics. This book deals first with the passive components of electronic systems, such as resistors, capacitors, and inductors. These topics are followed by a discussion on the analysis of electronic circuits, which involves three ways, namely, the actual circuit, graphical techniques, and rule of thumb. The remaining p

Electrons, Electronic Publishing, and Electronic Display.

Science.gov (United States)

Brownrigg, Edwin B.; Lynch, Clifford A.

1985-01-01

Provides a perspective on electronic publishing by distinguishing between "Newtonian" publishing and "quantum-mechanical" publishing. Highlights include media and publishing, works delivered through electronic media, electronic publishing and the printed word, management of intellectual property, and recent copyright-law issues…

Electron-electron Bremsstrahlung for bound target electrons

International Nuclear Information System (INIS)

Haug, E.

2008-01-01

For the process of electron-electron (e-e) Bremsstrahlung the momentum and energy distributions of the recoiling electrons are calculated in the laboratory frame. In order to get the differential cross section and the photon spectrum for target electrons which are bound to an atom, these formulae are multiplied by the incoherent scattering function and numerically integrated over the recoil energy. The effect of atomic binding is most pronounced at low energies of the incident electrons and for target atoms of high atomic numbers. The results are compared to those of previous calculations. (authors)

Asociación Thysanoptera (Insecta-Vicia faba (Fabaceae en la Prepuna y Puna de Jujuy, Argentina Thysanoptera (Insecta-Vicia faba (Fabaceae association in Prepuna and Puna in Jujuy, Argentina

Directory of Open Access Journals (Sweden)

María Inés Zamar

2012-03-01

. occidentalis utilizan la planta en forma temporal y oportunista en Prepuna, mientras que la presencia de F. gemina en Puna es esporádica. Se amplía el número de especies de tisanópteros asociadas al cultivo de haba en ArgentinaThysanoptera (Insecta-Vicia faba (Fabaceae association in Prepuna and Puna in Jujuy, Argentina. The different phenological stages of Vicia faba provide food resources and substrates for the development of a significant diversity of insects. This study aimed to identify the complex of anthophyllous thrips, analyze the species population fluctuations, to obtain some bioecological aspects and the role they play in this association. The study and sampling was conducted during the flowering-fruiting bean crop stages in two phytogeographical regions of Jujuy: Prepuna (2 479m asl on a weekly basis, from October-December 1995-1996 and Puna (3 367m asl every two weeks, from December 2007-March 2008. Each sample consisted of 25 flowers taken at random; only at Prepuna a complementary sampling of three hits per plant (n=10 plants was conducted. Observations were made on oviposition sites, admission to the flower, pupation sites, feeding behavior and injuries caused. In Prepuna, the Thysanoptera complex consisted of Frankliniella australis, F. occidentalis, F. gemina, F. schultzei and Thrips tabaci; in Puna, the specific diversity was restricted to F. australis and F. gemina. Although the planting-harvest period in both areas did not match, the fluctuations in populations showed the same pattern: as flowering progressed, the number of thrips coincided with the availability of food resources. In both areas, F. australis was the dominant species and maintained successive populations; it layed eggs in flower buds, and larvae hatched when flowers opened; feeding larvae and adults brought about silvery stains with black spots. In Prepuna, F. australis went through the mobile immature stages on flowers, while quiescent stages were on the ground; in the Puna, all

Interplay between electron-phonon and electron-electron interactions

International Nuclear Information System (INIS)

Roesch, O.; Gunnarsson, O.; Han, J.E.; Crespi, V.H.

2005-01-01

We discuss the interplay between electron-electron and electron-phonon interactions for alkali-doped fullerides and high temperature superconductors. Due to the similarity of the electron and phonon energy scales, retardation effects are small for fullerides. This raises questions about the origin of superconductivity, since retardation effects are believed to be crucial for reducing effects of the Coulomb repulsion in conventional superconductors. We demonstrate that by treating the electron-electron and electron-phonon interactions on an equal footing, superconductivity can be understood in terms of a local pairing. The Jahn-Teller character of the important phonons in fullerides plays a crucial role for this result. To describe effects of phonons in cuprates, we derive a t-J model with phonons from the three-band model. Using exact diagonalization for small clusters, we find that the anomalous softening of the half-breathing phonon as well as its doping dependence can be explained. By comparing the solution of the t-J model with the Hartree-Fock approximation for the three-band model, we address results obtained in the local-density approximation for cuprates. We find that genuine many-body results, due to the interplay between the electron-electron and electron-phonon interactions, play an important role for the the results in the t-J model. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

The sieve element occlusion gene family in dicotyledonous plants.

Science.gov (United States)

Ernst, Antonia M; Rüping, Boris; Jekat, Stephan B; Nordzieke, Steffen; Reineke, Anna R; Müller, Boje; Bornberg-Bauer, Erich; Prüfer, Dirk; Noll, Gundula A

2011-01-01

Sieve element occlusion (SEO) genes encoding forisome subunits have been identified in Medicago truncatula and other legumes. Forisomes are structural phloem proteins uniquely found in Fabaceae sieve elements. They undergo a reversible conformational change after wounding, from a condensed to a dispersed state, thereby blocking sieve tube translocation and preventing the loss of photoassimilates. Recently, we identified SEO genes in several non-Fabaceae plants (lacking forisomes) and concluded that they most probably encode conventional non-forisome P-proteins. Molecular and phylogenetic analysis of the SEO gene family has identified domains that are characteristic for SEO proteins. Here, we extended our phylogenetic analysis by including additional SEO genes from several diverse species based on recently published genomic data. Our results strengthen the original assumption that SEO genes seem to be widespread in dicotyledonous angiosperms, and further underline the divergent evolution of SEO genes within the Fabaceae.

Electronic emission and electron guns

International Nuclear Information System (INIS)

Roy, Amitava

2010-01-01

This paper reviews the process of electron emission from metal surface. Although electrons move freely in conductors like metals, they normally do not leave the metal without some manipulation. In fact, heating and bombardment are the two primary ways in which electrons are emitted through the use of a heating element behind the cathode (termed thermionic emission) or as a result of bombardment with a beam of electrons, ions, or metastable atoms (termed secondary emission). Another important emission mechanism called Explosive Electron Emission (EEE) is also often used in various High Voltage Pulse Power Systems to generate very high current (few hundreds of kA) pulsed electron beams. The electron gun is the device in that it shoots off a continuous (or pulsed) stream of electrons. A brief idea about the evolution of the electron gun components and their basis of functioning are also discussed. (author)

Tolerancia a la desecación de semillas de Prosopis ferox y Pterogyne nitens (Fabaceae

Directory of Open Access Journals (Sweden)

Marcelo Nahuel Morandini

2013-03-01

Full Text Available La elevada diversidad de especies y endemismos, conjuntamente con la acelerada pérdida de biodiversidad por deforestaciones, destaca la importancia de emprender acciones combinadas de conservación in situ y ex situ. El objetivo de este trabajo fue estudiar la tolerancia a la desecación de las semillas de Prosopis ferox y Pterogyne nitens, para su conservación ex situ a largo plazo en el BGEN. El contenido de humedad (CH se determinó colocando las semillas de cada población en estufa a 103°C y pesando las muestras a intervalos regulares hasta peso constante. Se realizaron ensayos de germinación en distintos CH: semillas frescas, 10-12%, 3-5%, y en semillas mantenidas seis meses a -20ºC y a 3-5% de CH. El CH de las semillas frescas de P. ferox fue de 14.2% y el de P. nitens de 10% para las dos poblaciones estudiadas. Las semillas de P. ferox llegaron a peso constante a las 17hr y las de P. nitens a las 3hr de secado. La germinación de las semillas de P. ferox fue mayor en los tratamientos con escarificación y la diferencia aumento con la reducción del CH y el almacenamiento. Las semillas de P. nitens con el CH reducido, requieren escarificación. Se concluye que las semillas de ambas especies son probablemente ortodoxas ya que la germinación superó el 80% en las semillas desecadas al 3-5% CH y almacenadas durante seis meses a -20°C.Desiccation tolerance in seeds of Prosopis ferox and Pterogyne nitens (Fabaceae. The high number of endemisms and species diversity together with the accelerated biodiversity loss by deforestation, especially in North Western Argentina, points out the need to work on species conservation combining ex situ and in situ strategies. The aim of this work was to study the desiccation tolerance in seeds of P. ferox and P. nitens for long term ex situ conservation at the Germplasm Bank of Native Species (BGEN of the National University of Salta (Argentina. The fruits were collected from ten individuals in P

Born-Oppenheimer Dynamics, Electronic Friction, and the Inclusion of Electron-Electron Interactions

Science.gov (United States)

Dou, Wenjie; Miao, Gaohan; Subotnik, Joseph E.

2017-07-01

We present a universal expression for the electronic friction as felt by a set of classical nuclear degrees of freedom (DOFs) coupled to a manifold of quantum electronic DOFs; no assumptions are made regarding the nature of the electronic Hamiltonian and electron-electron repulsions are allowed. Our derivation is based on a quantum-classical Liouville equation for the coupled electronic-nuclear motion, followed by an adiabatic approximation whereby electronic transitions are assumed to equilibrate faster than nuclear movement. The resulting form of friction is completely general, but does reduce to previously published expressions for the quadratic Hamiltonian (i.e., Hamiltonians without electronic correlation). At equilibrium, the second fluctuation-dissipation theorem is satisfied and the frictional matrix is symmetric. To demonstrate the importance of electron-electron correlation, we study electronic friction within the Anderson-Holstein model, where a proper treatment of electron-electron interactions shows signatures of a Kondo resonance and a mean-field treatment is completely inadequate.

Legume and Lotus japonicus Databases

DEFF Research Database (Denmark)

Hirakawa, Hideki; Mun, Terry; Sato, Shusei

2014-01-01

Since the genome sequence of Lotus japonicus, a model plant of family Fabaceae, was determined in 2008 (Sato et al. 2008), the genomes of other members of the Fabaceae family, soybean (Glycine max) (Schmutz et al. 2010) and Medicago truncatula (Young et al. 2011), have been sequenced. In this sec....... In this section, we introduce representative, publicly accessible online resources related to plant materials, integrated databases containing legume genome information, and databases for genome sequence and derived marker information of legume species including L. japonicus...

Effective electron-electron and electron-phonon interactions in the Hubbard-Holstein model

International Nuclear Information System (INIS)

Aprea, G.; Di Castro, C.; Grilli, M. . E-mail marco.grilli@roma1.infn.it; Lorenzana, J.

2006-01-01

We investigate the interplay between the electron-electron and the electron-phonon interaction in the Hubbard-Holstein model. We implement the flow-equation method to investigate within this model the effect of correlation on the electron-phonon effective coupling and, conversely, the effect of phonons in the effective electron-electron interaction. Using this technique we obtain analytical momentum-dependent expressions for the effective couplings and we study their behavior for different physical regimes. In agreement with other works on this subject, we find that the electron-electron attraction mediated by phonons in the presence of Hubbard repulsion is peaked at low transferred momenta. The role of the characteristic energies involved is also analyzed

Electron-electron coincidence spectroscopies at surfaces

International Nuclear Information System (INIS)

Stefani, G.; Iacobucci, S.; Ruocco, A.; Gotter, R.

2002-01-01

In the past 20 years, a steadily increasing number of electron-electron coincidence experiments on atoms and molecules have contributed to a deeper understanding of electron-electron correlation effects. In more recent years this technique has been extended to the study of solid surfaces. This class of one photon IN two electrons OUT experiments will be discussed with an emphasis on grazing incidence geometry, that is expected to be particularly suited for studying surfaces. The crucial question of which is the dominant mechanism that leads to ejection of pairs of electron from the surface will be addressed. It will be shown that, depending on the kinematics chosen, the correlated behaviour of the pairs of electrons detected might be singled out from independent particle one

La semilla de Campsiandra angustifolia (Fabaceae:Caesalpiniodeaecomo un reflejo de las presiones selectivas sobre su dispersión y establecimiento

Directory of Open Access Journals (Sweden)

Alejandro G Farji-Brener

2005-06-01

Full Text Available Evaluamos indirectamente las presiones selectivas sobre la dispersión y el establecimiento en Campsiandra angustifolia, un árbol de la Amazonía Peruana dispersado por agua, analizando variaciones de la relación entre el volumen ocupado por las estructuras de dispersión y de establecimiento en sus semillas. Medimos un total de 535 semillas de 13 árboles ubicados en tres hábitats diferentes, las cuales presentaron una gran variación en su volumen total. Independientemente del tamaño de la semilla y de la ubicación del árbol de origen, la relación entre el volumen asignado a estructuras de establecimiento y a estructuras de dispersión fue relativamente constante (~1 y presentó una distribución normal con baja asimetría, indicando selección estabilizante. Este resultado sugiere que los procesos de dispersión y establecimiento poseen una importancia relativa similar para C.angustifolia en los hábitats estudiados. En especies con semillas empaquetadas, el volumen relativo ocupado por estructuras relacionadas con la dispersión o el establecimiento podría ser una medida más adecuada de la solución de compromiso entre estos dos procesos que la variación del tamaño de la semillaThe seeds of Campsiandra angustifolia (Fabaceae:Caesalpiniodeae as a reflex of selective pressures on dispersal and establishment. We indirectly evaluated the selective pressures on dispersal and establishment of Campsiandra angustifolia, a common water-dispersed tree from the Peruvian Amazon, analyzing the variation in the relationship between the volume occupied by dispersal and establishment structures in a total of 535 seeds from 13 trees located at three different habitats. The seeds differed one order of magnitude in their total volume. However, independently of their size and the location of the maternal tree, the relationship between the volume occupied by dispersal and establishment structures was relatively constant (~1 and showed a normal

Electron distribution function in electron-beam-excited plasmas

International Nuclear Information System (INIS)

Brau, C.A.

1976-01-01

In monatomic plasmas excited by high-intensity relativistic electron beams, the electron secondary distribution function is dominated by elastic electron-electron collisions at low electron energies and by inelastic electron-atom collisions at high electron energies (above the excitation threshold). Under these conditions, the total rate of excitation by inelastic collisions is limited by the rate at which electron-electron collisions relax the distribution function in the neighborhood of the excitation threshold. To describe this effect quantitatively, an approximate analytic solution of the electron Boltzmann equation is obtained, including both electron-electron and inelastic collisions. The result provides a simple formula for the total rate of excitation

Hard electronics; Hard electronics

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

Hard material technologies were surveyed to establish the hard electronic technology which offers superior characteristics under hard operational or environmental conditions as compared with conventional Si devices. The following technologies were separately surveyed: (1) The device and integration technologies of wide gap hard semiconductors such as SiC, diamond and nitride, (2) The technology of hard semiconductor devices for vacuum micro- electronics technology, and (3) The technology of hard new material devices for oxides. The formation technology of oxide thin films made remarkable progress after discovery of oxide superconductor materials, resulting in development of an atomic layer growth method and mist deposition method. This leading research is expected to solve such issues difficult to be easily realized by current Si technology as high-power, high-frequency and low-loss devices in power electronics, high temperature-proof and radiation-proof devices in ultimate electronics, and high-speed and dense- integrated devices in information electronics. 432 refs., 136 figs., 15 tabs.

Electron radiography

Science.gov (United States)

Merrill, Frank E.; Morris, Christopher

2005-05-17

A system capable of performing radiography using a beam of electrons. Diffuser means receive a beam of electrons and diffuse the electrons before they enter first matching quadrupoles where the diffused electrons are focused prior to the diffused electrons entering an object. First imaging quadrupoles receive the focused diffused electrons after the focused diffused electrons have been scattered by the object for focusing the scattered electrons. Collimator means receive the scattered electrons and remove scattered electrons that have scattered to large angles. Second imaging quadrupoles receive the collimated scattered electrons and refocus the collimated scattered electrons and map the focused collimated scattered electrons to transverse locations on an image plane representative of the electrons' positions in the object.

Electron transfer from electronic excited states to sub-vacuum electron traps in amorphous ice

International Nuclear Information System (INIS)

Vichnevetski, E.; Bass, A.D.; Sanche, L.

2000-01-01

We investigate the electron stimulated yield of electronically excited argon atoms (Ar * ) from monolayer quantities of Ar deposited onto thin films of amorphous ice. Two peaks of narrow width ( - electron-exciton complex into exciton states, by the transfer of an electron into a sub-vacuum electron state within the ice film. However, the 10.7 eV feature is shifted to lower energy since electron attachment to Ar occurs within small pores of amorphous ice. In this case, the excess electron is transferred into an electron trap below the conduction band of the ice layer

Monte Carlo study of electron relaxation in graphene with spin polarized, degenerate electron gas in presence of electron-electron scattering

Science.gov (United States)

Borowik, Piotr; Thobel, Jean-Luc; Adamowicz, Leszek

2017-12-01

The Monte Carlo simulation method is applied to study the relaxation of excited electrons in monolayer graphene. The presence of spin polarized background electrons population, with density corresponding to highly degenerate conditions is assumed. Formulas of electron-electron scattering rates, which properly account for electrons presence in two energetically degenerate, inequivalent valleys in this material are presented. The electron relaxation process can be divided into two phases: thermalization and cooling, which can be clearly distinguished when examining the standard deviation of electron energy distribution. The influence of the exchange effect in interactions between electrons with parallel spins is shown to be important only in transient conditions, especially during the thermalization phase.

STUDY ON POLLEN VIABILITY AS BIOINDICATOR OF AIR QUALITY

Directory of Open Access Journals (Sweden)

Florentina ŞTEFLEA

2012-01-01

Full Text Available The aim of this research is to estimate the relationship between pollen viability and atmospheric pollution (in polluted and non-polluted conditions. The study was carried out in the city of Timisoara. Two areas, with different intensity of road traffic (very high and absent but all characterized by the presence of the same plant species, were selected. The pollen of herbaceous spontaneous species, arboreal species and a shrub species was used (Robinia pseudacacia, Aesculus x carnea, Catalpa bignonioides, Albizzia julibrissin, Rosa canina, Sambucus nigra, Malva neglecta, Ranunculus acer, Trifolium repens, Cichorium intybus. The pollen of these species was treated with TTC (2, 3, 5 Tryphenil-Tetrazolium-Chloride staining solution and viability was then estimated by light microscopy. The results of the mean pollen viability percentage of the examined species are reported. Pollen viability of herbaceous plants is significantly different between the two environments.

Electron attachment cross sections obtained from electron attachment spectroscopy

International Nuclear Information System (INIS)

Popp, P.; Baumbach, J.I.; Leonhardt, J.W.; Mothes, S.

1988-01-01

Electron capture detectors have a high sensitivity for substances with high thermal electron attachment cross sections. The electron attachment spectroscopy makes it possible to change the mean electron energy in such a way that the maximum for dissociative electron attachment is reached. Thus, best operation modes of the detection system as well as significant dependencies of electron attachment coefficients are available. Cross sections for electron attachment as a function of the electron energy are obtained with the knowledge of electron energy distribution functions from Boltzmann equation analysis by a special computer code. A disadvantage of this electron attachment spectroscopy is the superposition of space charge effects due to the decrease of the electron drift velocity with increasing mean electron energy. These influences are discussed. (author)

Electron beam effects in auger electron spectroscopy and scanning electron microscopy

International Nuclear Information System (INIS)

Fontaine, J.M.; Duraud, J.P.; Le Gressus, C.

1979-01-01

Electron beam effects on Si(100) and 5% Fe/Cr alloy samples have been studied by measurements of the secondary electron yield delta, determination of the surface composition by Auger electron spectroscopy and imaging with scanning electron microscopy. Variations of delta as a function of the accelerating voltage Esub(p) (0.5 -9 Torr has no effect on technological samples covered with their reaction layers; the sensitivities to the beam depend rather on the earlier mechanical, thermal and chemical treatment of the surfaces. (author)

The effect of electron-electron interaction induced dephasing on electronic transport in graphene nanoribbons

Energy Technology Data Exchange (ETDEWEB)

Kahnoj, Sina Soleimani; Touski, Shoeib Babaee [School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395-515, Tehran (Iran, Islamic Republic of); Pourfath, Mahdi, E-mail: pourfath@ut.ac.ir, E-mail: pourfath@iue.tuwien.ac.at [School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395-515, Tehran (Iran, Islamic Republic of); Institute for Microelectronics, TU Wien, Gusshausstrasse 27–29/E360, 1040 Vienna (Austria)

2014-09-08

The effect of dephasing induced by electron-electron interaction on electronic transport in graphene nanoribbons is theoretically investigated. In the presence of disorder in graphene nanoribbons, wavefunction of electrons can set up standing waves along the channel and the conductance exponentially decreases with the ribbon's length. Employing the non-equilibrium Green's function formalism along with an accurate model for describing the dephasing induced by electron-electron interaction, we show that this kind of interaction prevents localization and transport of electrons remains in the diffusive regime where the conductance is inversely proportional to the ribbon's length.

Electron Beam Generation in Tevatron Electron Lenses

International Nuclear Information System (INIS)

Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.

2006-01-01

New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices

Electron beam generation in Tevatron electron lenses

International Nuclear Information System (INIS)

Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.

2006-01-01

New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices

Electronic technology

International Nuclear Information System (INIS)

Kim, Jin Su

2010-07-01

This book is composed of five chapters, which introduces electronic technology about understanding of electronic, electronic component, radio, electronic application, communication technology, semiconductor on its basic, free electron and hole, intrinsic semiconductor and semiconductor element, Diode such as PN junction diode, characteristic of junction diode, rectifier circuit and smoothing circuit, transistor on structure of transistor, characteristic of transistor and common emitter circuit, electronic application about electronic equipment, communication technology and education, robot technology and high electronic technology.

The Electron

Energy Technology Data Exchange (ETDEWEB)

Thomson, George

1972-01-01

Electrons are elementary particles of atoms that revolve around and outside the nucleus and have a negative charge. This booklet discusses how electrons relate to electricity, some applications of electrons, electrons as waves, electrons in atoms and solids, the electron microscope, among other things.

Determination of the electron-electron collisional frequency by means of plasma electron spectroscopy

International Nuclear Information System (INIS)

Kolokolov, N.B.; Kudryavtsev, A.A.; Romanenko, V.A.

1989-01-01

Methods of controlling fast part of electron distribution function (DF) in nonlocal regime of current-free plasma are suggested and realized. Artificially created step in DF fast part has a simple link with frequencies of electron-electron and elastic electron-atom collisions that may be defined in the corresponding experiments

Electron beam-plasma interaction and electron-acoustic solitary waves in a plasma with suprathermal electrons

Science.gov (United States)

Danehkar, A.

2018-06-01

Suprathermal electrons and inertial drifting electrons, so called electron beam, are crucial to the nonlinear dynamics of electrostatic solitary waves observed in several astrophysical plasmas. In this paper, the propagation of electron-acoustic solitary waves (EAWs) is investigated in a collisionless, unmagnetized plasma consisting of cool inertial background electrons, hot suprathermal electrons (modeled by a κ-type distribution), and stationary ions. The plasma is penetrated by a cool electron beam component. A linear dispersion relation is derived to describe small-amplitude wave structures that shows a weak dependence of the phase speed on the electron beam velocity and density. A (Sagdeev-type) pseudopotential approach is employed to obtain the existence domain of large-amplitude solitary waves, and investigate how their nonlinear structures depend on the kinematic and physical properties of the electron beam and the suprathermality (described by κ) of the hot electrons. The results indicate that the electron beam can largely alter the EAWs, but can only produce negative polarity solitary waves in this model. While the electron beam co-propagates with the solitary waves, the soliton existence domain (Mach number range) becomes narrower (nearly down to nil) with increasing the beam speed and the beam-to-hot electron temperature ratio, and decreasing the beam-to-cool electron density ratio in high suprathermality (low κ). It is found that the electric potential amplitude largely declines with increasing the beam speed and the beam-to-cool electron density ratio for co-propagating solitary waves, but is slightly decreased by raising the beam-to-hot electron temperature ratio.

Electronic Government and Electronic Participation

NARCIS (Netherlands)

Tambouris, E; Scholl, H.J.; Janssen, M.F.W.H.A.; Wimmer, M.A.; Tarabanis, K; Gascó, M; Klievink, A.J.; Lindgren, I; Milano, M; Panagiotopoulos, P; Pardo, T.A.; Parycek, P; Sæbø, Ø

2016-01-01

Electronic government and electronic participation continue to transform the public sector and society worldwide and are constantly being transformed themselves by emerging information and communication technologies.This book presents papers from the 14th International Federation for Information

Electronic Government and Electronic Participation

NARCIS (Netherlands)

Tambouris, E.; Scholl, H.J.; Janssen, M.F.W.H.A.; Wimmer, M.A.; Tarabanis, K.; Gascó, M.; Klievink, A.J.; Lindgren, I.; Milano, M.; Panagiotopoulos, P.; Pardo, T.A.; Parycek, P.; Sæbø, O.

2015-01-01

Electronic government and electronic participation continue to transform the public sector and society worldwide and are constantly being transformed themselves by emerging information and communication technologies. This book presents papers from the 14th International Federation for Information

Electron detector

International Nuclear Information System (INIS)

Hashimoto, H.; Mogami, A.

1975-01-01

A device for measuring electron densities at a given energy level in an electron beam or the like having strong background noise, for example, in the detection of Auger electric energy spectrums is described. An electron analyzer passes electrons at the given energy level and at the same time electrons of at least one adjacent energy level. Detecting means associated therewith produce signals indicative of the densities of the electrons at each energy level and combine these signals to produce a signal indicative of the density of the electrons of the given energy level absent background noise

Electron-electron interactions in artificial graphene

Science.gov (United States)

Rasanen, Esa

2013-03-01

Recent advances in the creation and modulation of graphenelike systems are introducing a science of ``designer Dirac materials.'' In its original definition, artificial graphene is a man-made nanostructure that consists of identical potential wells (quantum dots) arranged in an adjustable honeycomb lattice in the two-dimensional electron gas. As our ability to control the quality of artificial graphene samples improves, so grows the need for an accurate theory of its electronic properties, including the effects of electron-electron interactions. Here we determine those effects on the band structure and on the emergence of Dirac points, and discuss future investigations and challenges in this field.

Decal electronics for printed high performance cmos electronic systems

KAUST Repository

Hussain, Muhammad Mustafa

2017-11-23

High performance complementary metal oxide semiconductor (CMOS) electronics are critical for any full-fledged electronic system. However, state-of-the-art CMOS electronics are rigid and bulky making them unusable for flexible electronic applications. While there exist bulk material reduction methods to flex them, such thinned CMOS electronics are fragile and vulnerable to handling for high throughput manufacturing. Here, we show a fusion of a CMOS technology compatible fabrication process for flexible CMOS electronics, with inkjet and conductive cellulose based interconnects, followed by additive manufacturing (i.e. 3D printing based packaging) and finally roll-to-roll printing of packaged decal electronics (thin film transistors based circuit components and sensors) focusing on printed high performance flexible electronic systems. This work provides the most pragmatic route for packaged flexible electronic systems for wide ranging applications.

Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

Energy Technology Data Exchange (ETDEWEB)

Han, Myung-Geun, E-mail: mghan@bnl.gov [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Garlow, Joseph A. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794 (United States); Marshall, Matthew S.J.; Tiano, Amanda L. [Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Wong, Stanislaus S. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Cheong, Sang-Wook [Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854 (United States); Walker, Frederick J.; Ahn, Charles H. [Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520 (United States); Zhu, Yimei [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2017-05-15

Highlights: • Electron-beam-induced-current (EBIC) and active secondary-electron voltage-contrast (SE-VC) are demonstrated in STEM mode combined with in situ electrical biasing in a TEM. • Electrostatic potential maps in ferroelectric thin films, multiferroic nanowires, and single crystals obtained by off-axis electron holography were compared with EBIC and SE-VC data. • Simultaneous EBIC and active SE-VC performed with atomic resolution STEM are demonstrated. - Abstract: The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.

Electronic Commerce and Electronic Business

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

This special issue is motivated by the recent upsurge of research activity in the areas of electronic commerce and electronic business both in India and all over the world. The current ... Monte Carlo methods for pricing financial options are then.

Large-scale pattern of genetic differentiation within African rainforest trees: insights on the roles of ecological gradients and past climate changes on the evolution of Erythrophleum spp (Fabaceae).

Science.gov (United States)

Duminil, Jerome; Brown, Richard P; Ewédjè, Eben-Ezer B K; Mardulyn, Patrick; Doucet, Jean-Louis; Hardy, Olivier J

2013-09-12

The evolutionary events that have shaped biodiversity patterns in the African rainforests are still poorly documented. Past forest fragmentation and ecological gradients have been advocated as important drivers of genetic differentiation but their respective roles remain unclear. Using nuclear microsatellites (nSSRs) and chloroplast non-coding sequences (pDNA), we characterised the spatial genetic structure of Erythrophleum (Fabaceae) forest trees in West and Central Africa (Guinea Region, GR). This widespread genus displays a wide ecological amplitude and taxonomists recognize two forest tree species, E. ivorense and E. suaveolens, which are difficult to distinguish in the field and often confused. Bayesian-clustering applied on nSSRs of a blind sample of 648 specimens identified three major gene pools showing no or very limited introgression. They present parapatric distributions correlated to rainfall gradients and forest types. One gene pool is restricted to coastal evergreen forests and corresponds to E. ivorense; a second one is found in gallery forests from the dry forest zone of West Africa and North-West Cameroon and corresponds to West-African E. suaveolens; the third gene pool occurs in semi-evergreen forests and corresponds to Central African E. suaveolens. These gene pools have mostly unique pDNA haplotypes but they do not form reciprocally monophyletic clades. Nevertheless, pDNA molecular dating indicates that the divergence between E. ivorense and Central African E. suaveolens predates the Pleistocene. Further Bayesian-clustering applied within each major gene pool identified diffuse genetic discontinuities (minor gene pools displaying substantial introgression) at a latitude between 0 and 2°N in Central Africa for both species, and at a longitude between 5° and 8°E for E. ivorense. Moreover, we detected evidence of past population declines which are consistent with historical habitat fragmentation induced by Pleistocene climate changes. Overall

Electron optical characteristics of a concave electrostatic electron mirror for a scanning electron microscope

International Nuclear Information System (INIS)

Hamarat, R.T.; Witzani, J.; Hoerl, E.M.

1984-08-01

Numerical computer calculations are used to explore the design characteristics of a concave electrostatic electron mirror for a mirror attachment for a conventional scanning electron microscope or an instrument designed totally as a scanning electron mirror microscope. The electron paths of a number of set-ups are calculated and drawn graphically in order to find the optimum shape and dimensions of the mirror geometry. This optimum configuration turns out to be the transition configuration between two cases of electron path deflection, towards the optical axis of the system and away from it. (Author)

Electronic processes in organic electronics bridging nanostructure, electronic states and device properties

CERN Document Server

Kudo, Kazuhiro; Nakayama, Takashi; Ueno, Nobuo

2015-01-01

The book covers a variety of studies of organic semiconductors, from fundamental electronic states to device applications, including theoretical studies. Furthermore, innovative experimental techniques, e.g., ultrahigh sensitivity photoelectron spectroscopy, photoelectron yield spectroscopy, spin-resolved scanning tunneling microscopy (STM), and a material processing method with optical-vortex and polarization-vortex lasers, are introduced. As this book is intended to serve as a textbook for a graduate level course or as reference material for researchers in organic electronics and nanoscience from electronic states, fundamental science that is necessary to understand the research is described. It does not duplicate the books already written on organic electronics, but focuses mainly on electronic properties that arise from the nature of organic semiconductors (molecular solids). The new experimental methods introduced in this book are applicable to various materials (e.g., metals, inorganic and organic mater...

Redescripción de la obrera de Myrmelachista gallicola (Hymenoptera: Formicidae y primera cita para la provincia de La Pampa (Argentina Redescription of the worker of Myrmelachista gallicola (Hymenoptera: Formicidae and first record from La Pampa (Argentina

Directory of Open Access Journals (Sweden)

Estela M. Quirán

2006-12-01

Full Text Available Se redescribe la obrera de Myrmelachista gallicola Mayr y se cita por primera vez para la provincia de La Pampa (Argentina. El material estudiado está compuesto por obreras y fue recolectado sobre Prosopis caldenia Burkart (Fabaceae, dentro de las agallas de Tetradiplosis sp. (Diptera: Cecidomyiidae, en la periferia de la ciudad de Santa Rosa, provincia de La Pampa.The worker of Myrmelachista gallicola Mayr is redescribed and mentioned for the first time for La Pampa province (Argentina. The material studied was integrated by workers and was collected on Prosopis caldenia Burkart (Fabaceae at Santa Rosa, La Pampa within galls of Tetradiplosis sp. (Diptera: Cecidomyiidae.

A new species of Eccopsis Zeller (Lepidoptera, Tortricidae from the coastal valleys of northern Chile, with the first continental record of E. galapagana Razowski & Landry

Directory of Open Access Journals (Sweden)

Héctor A. Vargas

2011-06-01

Full Text Available A new species of Eccopsis Zeller (Lepidoptera, Tortricidae from the coastal valleys of northern Chile, with the first continental record of E. galapagana Razowski & Landry. Eccopsis Zeller, 1852 is reported for the first time from Chile. Eccopsis razowskii Vargas, n. sp. is described and illustrated based on specimens reared from larvae collected on native Acacia macracantha Willd. (Fabaceae in the coastal valleys of the northern Chilean desert. Eccopsis galapagana Razowski & Landry, 2008, previously known only from the Galapagos Islands, Ecuador, is recorded for the first time from continental South America. Larvae of the latter were collected in northern Chile feeding on Prosopis alba Griseb (Fabaceae.

Decal electronics for printed high performance cmos electronic systems

KAUST Repository

Hussain, Muhammad Mustafa; Sevilla, Galo Torres; Cordero, Marlon Diaz; Kutbee, Arwa T.

2017-01-01

High performance complementary metal oxide semiconductor (CMOS) electronics are critical for any full-fledged electronic system. However, state-of-the-art CMOS electronics are rigid and bulky making them unusable for flexible electronic applications

Precession mechanism of spin relaxation at frequent electron-electron collisions

CERN Document Server

Glazov, M M

2002-01-01

It is shown that the spin relaxation mechanism in the two-dimensional electron gas, is controlled not only through the electron pulse relaxation processes, determining the mobility, but through the electron-electron collisions as well. It is decided to use the kinetic equation, describing the electron spin mixing in the k-space, for determining the spin relaxation time tau sub s at frequent electron-electron collisions. The tau sub s time is calculated for the nondegenerated electron gas both with an account and with no account of the exchange interaction

Practical electronics handbook

CERN Document Server

Sinclair, Ian R

2013-01-01

Practical Electronics Handbook, Third Edition provides the frequently used and highly applicable principles of electronics and electronic circuits.The book contains relevant information in electronics. The topics discussed in the text include passive and active discrete components; linear and digital I.C.s; microprocessors and microprocessor systems; digital-analogue conversions; computer aids in electronics design; and electronic hardware components.Electronic circuit constructors, service engineers, electronic design engineers, and anyone with an interest in electronics will find the book ve

Composition quantification of electron-transparent samples by backscattered electron imaging in scanning electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Müller, E., E-mail: erich.mueller@kit.edu; Gerthsen, D.

2017-02-15

The contrast of backscattered electron (BSE) images in scanning electron microscopy (SEM) depends on material parameters which can be exploited for composition quantification if some information on the material system is available. As an example, the In-concentration in thin In{sub x}Ga{sub 1−x}As layers embedded in a GaAs matrix is analyzed in this work. The spatial resolution of the technique is improved by using thin electron-transparent specimens instead of bulk samples. Although the BSEs are detected in a comparably small angular range by an annular semiconductor detector, the image intensity can be evaluated to determine the composition and local thickness of the specimen. The measured intensities are calibrated within one single image to eliminate the influence of the detection and amplification system. Quantification is performed by comparison of experimental and calculated data. Instead of using time-consuming Monte-Carlo simulations, an analytical model is applied for BSE-intensity calculations which considers single electron scattering and electron diffusion. - Highlights: • Sample thickness and composition are quantified by backscattered electron imaging. • A thin sample is used to achieve spatial resolution of few nanometers. • Calculations are carried out with a time-saving electron diffusion model. • Small differences in atomic number and density detected at low electron energies.

Nonlinear electron-acoustic rogue waves in electron-beam plasma system with non-thermal hot electrons

Science.gov (United States)

Elwakil, S. A.; El-hanbaly, A. M.; Elgarayh, A.; El-Shewy, E. K.; Kassem, A. I.

2014-11-01

The properties of nonlinear electron-acoustic rogue waves have been investigated in an unmagnetized collisionless four-component plasma system consisting of a cold electron fluid, non-thermal hot electrons obeying a non-thermal distribution, an electron beam and stationary ions. It is found that the basic set of fluid equations is reduced to a nonlinear Schrodinger equation. The dependence of rogue wave profiles on the electron beam and energetic population parameter are discussed. The results of the present investigation may be applicable in auroral zone plasma.

Electron-cyclotron-resonant-heated electron distribution functions

International Nuclear Information System (INIS)

Matsuda, Y.; Nevins, W.M.; Cohen, R.H.

1981-01-01

Recent studies at Lawrence Livermore National Laboratory (LLNL) with a bounce-averaged Fokker-Planck code indicate that the energetic electron tail formed by electron-cyclotron resonant heating (ECRH) at the second harmonic is not Maxwellian. We present the results of our bounce-averaged Fokker-Planck code along with some simple analytic models of hot-electron distribution functions

Attainment of Electron Beam Suitable for Medium Energy Electron Cooling

International Nuclear Information System (INIS)

Seletskiy, Sergey M.; Rochester U.

2005-01-01

Electron cooling of charged particle beams is a well-established technique at electron energies of up to 300 keV. However, up to the present time the advance of electron cooling to the MeV-range energies has remained a purely theoretical possibility. The electron cooling project at Fermilab has recently demonstrated the first cooling of 8.9 GeV/c antiprotons in the Recycler ring, and therefore, has proved the validity of the idea of relativistic electron cooling. The Recycler Electron Cooler (REC) is the key component of the Tevatron Run II luminosity upgrade project. Its performance depends critically on the quality of electron beam. A stable electron beam of 4.3 MeV carrying 0.5 A of DC current is required. The beam suitable for the Recycler Electron Cooler must have an angular spread not exceeding 200 (micro)rad. The full-scale prototype of the REC was designed, built and tested at Fermilab in the Wideband laboratory to study the feasibility of attaining the high-quality electron beam. In this thesis I describe various aspects of development of the Fermilab electron cooling system, and the techniques used to obtain the electron beam suitable for the cooling process. In particular I emphasize those aspects of the work for which I was principally responsible. Chapter 1 is an introduction where I describe briefly the theory and the history of electron cooling, and derive the requirements to the quality of electron beam and requirements to the basic parameters of the Recycler Electron Cooler. Chapter 2 is devoted to the theoretical consideration of the motion of electrons in the cooling section, description of the cooling section and of the measurement of the magnetic fields. In Chapter 3 I consider different factors that increase the effective electron angle in the cooling section and suggest certain algorithms for the suppression of parasitic angles. Chapter 4 is devoted to the measurements of the energy of the electron beam. In the concluding Chapter 5 I review

Double differential distributions of electron emission in ion-atom and electron-atom collisions using an electron spectrometer

International Nuclear Information System (INIS)

Misra, Deepankar; Thulasiram, K.V.; Fernandes, W.; Kelkar, Aditya H.; Kadhane, U.; Kumar, Ajay; Singh, Yeshpal; Gulyas, L.; Tribedi, Lokesh C.

2009-01-01

We study electron emission from atoms and molecules in collisions with fast electrons and heavy ions (C 6+ ). The soft collision electrons (SE), two center electron emission (TCEE), the binary encounter (BE) events and the KLL Auger lines along with the elastically scattered peaks (in electron collisions) are studied using a hemispherical electrostatic electron analyzer. The details of the measurements along with description of the spectrometer and data acquisition system are given. The angular distributions of the low energy (few eV) electrons in soft collisions and the binary encounter electrons at keV energies are compared with quantum mechanical models based on the first Born (B1) and the continuum distorted wave-Eikonal initial state approximation (CDW-EIS).

VIRTUAL ELECTRONIC COMPONENTS OF THE ELECTRONIC EQUIPMENT

Directory of Open Access Journals (Sweden)

E. Lazarevich

2013-01-01

Full Text Available The article is present new idea of the creation, developments and improvements of the electronic equipment of complex systems by means of the virtual electronic components. The idea of the virtual electronic components is a presentation and perception of the creation and developments of the equipment on two forming: real – in the manner of standard marketed block of the intellectual property and image – in the manner of virtual component. The real component in most cases slows the development of the electronic equipment. The imaginary component is the «locomotive» of development of the electronic equipment. The Imaginary component contains the scientific has brushed against developer. The scientific has brushed against developer reveals of itself in the manner of virtual component on the modern level of the design rates of microelectronics.

Sieve element occlusion (SEO) genes encode structural phloem proteins involved in wound sealing of the phloem.

Science.gov (United States)

Ernst, Antonia M; Jekat, Stephan B; Zielonka, Sascia; Müller, Boje; Neumann, Ulla; Rüping, Boris; Twyman, Richard M; Krzyzanek, Vladislav; Prüfer, Dirk; Noll, Gundula A

2012-07-10

The sieve element occlusion (SEO) gene family originally was delimited to genes encoding structural components of forisomes, which are specialized crystalloid phloem proteins found solely in the Fabaceae. More recently, SEO genes discovered in various non-Fabaceae plants were proposed to encode the common phloem proteins (P-proteins) that plug sieve plates after wounding. We carried out a comprehensive characterization of two tobacco (Nicotiana tabacum) SEO genes (NtSEO). Reporter genes controlled by the NtSEO promoters were expressed specifically in immature sieve elements, and GFP-SEO fusion proteins formed parietal agglomerates in intact sieve elements as well as sieve plate plugs after wounding. NtSEO proteins with and without fluorescent protein tags formed agglomerates similar in structure to native P-protein bodies when transiently coexpressed in Nicotiana benthamiana, and the analysis of these protein complexes by electron microscopy revealed ultrastructural features resembling those of native P-proteins. NtSEO-RNA interference lines were essentially devoid of P-protein structures and lost photoassimilates more rapidly after injury than control plants, thus confirming the role of P-proteins in sieve tube sealing. We therefore provide direct evidence that SEO genes in tobacco encode P-protein subunits that affect translocation. We also found that peptides recently identified in fascicular phloem P-protein plugs from squash (Cucurbita maxima) represent cucurbit members of the SEO family. Our results therefore suggest a common evolutionary origin for P-proteins found in the sieve elements of all dicotyledonous plants and demonstrate the exceptional status of extrafascicular P-proteins in cucurbits.

Anti-infective effects of Brazilian Caatinga plants against pathogenic bacterial biofilm formation.

Science.gov (United States)

Silva, Laura Nunes; Trentin, Danielle da Silva; Zimmer, Karine Rigon; Treter, Janine; Brandelli, Clara Lia Costa; Frasson, Amanda Piccoli; Tasca, Tiana; da Silva, Alexandre Gomes; da Silva, Márcia Vanusa; Macedo, Alexandre José

2015-03-01

The local communities living in the Brazilian Caatinga biome have a significant body of traditional knowledge on a considerable number of medicinal plants used to heal several maladies. Based on ethnopharmacological data, this study screened 23 aqueous plant extracts against two well-known models of biofilm-forming bacteria: Staphylococcus epidermidis and Pseudomonas aeruginosa. Crystal violet assay and scanning electron microscopy (SEM) were used to evaluate the effect of extracts on biofilm formation and measurements of the absorbance at 600 nm to assess bacterial growth. Selected extracts were investigated regarding the cytotoxicity by MTT assay using mammal cells and the qualitative phytochemical fingerprint by thin layer chromatography. Harpochilus neesianus Mart. ex Nees. (Acanthaceae) leaves, Apuleia leiocarpa Vogel J. F. Macbr. (Fabaceae), and Poincianella microphylla Mart. ex G. Don L. P. Queiroz (Fabaceae) fruits showed non-biocidal antibiofilm action against S. epidermidis with activities of 69, 52, and 63%, respectively. SEM confirmed that biofilm structure was strongly prevented and that extracts promoted overproduction of the matrix and/or bacterial morphology modification. Poincianella microphylla demonstrated toxicity at 4.0 mg/mL and 2.0 mg/mL, A. leiocarpa presented toxicity only at 4.0 mg/mL, whereas H. neesianus presented the absence of toxicity against Vero cell line. Preliminary phytochemical analysis revealed the presence of flavonoids, terpenoids, steroids, amines, and polyphenols. This work provides a scientific basis which may justify the ethnopharmacological use of the plants herein studied, indicating extracts that possess limited mammal cytotoxicity in vitro and a high potential as a source of antibiofilm drugs prototypes.

A new stage of nuclear electronics-particle electronics

International Nuclear Information System (INIS)

Xi Deming

1987-01-01

The rapid development of high energy physics experiments has pushed the nuclear electronics to a new stage, i.e. the particle electronics. In this paper the background, main features and recent trends of the particle electronics are expounded

Electron transport effects in ion induced electron emission

Energy Technology Data Exchange (ETDEWEB)

Dubus, A. [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. FD Roosevelt, B-1050 Brussels (Belgium)]. E-mail: adubus@ulb.ac.be; Pauly, N. [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. FD Roosevelt, B-1050 Brussels (Belgium); Roesler, M. [Karl-Pokern-Str. 12, D-12587 Berlin (Germany)

2007-03-15

Ion induced electron emission (IIEE) is usually described as a three-step process, i.e. electron excitation by the incident projectile, electron transport (and multiplication) and electron escape through the potential barrier at the surface. In many cases, the first step of the process has been carefully described. The second step of the process, i.e. electron transport and multiplication, has often been treated in a very rough way, a simple decreasing exponential law being sometimes used. It is precisely the aim of the present work to show the importance of a correct description of electron transport and multiplication in a theoretical calculation of IIEE. A short overview of the electron transport models developed for IIEE is given in this work. The so-called 'Infinite medium slowing-down model' often used in recent works is evaluated by means of Monte Carlo simulations. In particular, the importance of considering correctly the semi-infinite character of the medium and the boundary condition at the vacuum-medium interface is discussed. Quantities like the electron escape depth are also briefly discussed. This evaluation has been performed in the particular case of protons (25keV

Studying electron-PAG interactions using electron-induced fluorescence

Science.gov (United States)

Narasimhan, Amrit; Grzeskowiak, Steven; Ostrander, Jonathan; Schad, Jonathon; Rebeyev, Eliran; Neisser, Mark; Ocola, Leonidas E.; Denbeaux, Gregory; Brainard, Robert L.

2016-03-01

In extreme ultraviolet (EUV) lithography, 92 eV photons are used to expose photoresists. Typical EUV resists are organic-based and chemically amplified using photoacid generators (PAGs). Upon exposure, PAGs produce acids which catalyze reactions that result in changes in solubility. In EUV lithography, photo- and secondary electrons (energies of 10- 80 eV) play a large role in PAG acid-production. Several mechanisms for electron-PAG interactions (e.g. electron trapping, and hole-initiated chemistry) have been proposed. The aim of this study is to explore another mechanism - internal excitation - in which a bound PAG electron can be excited by receiving energy from another energetic electron, causing a reaction that produces acid. This paper explores the mechanism of internal excitation through the analogous process of electron-induced fluorescence, in which an electron loses energy by transferring that energy to a molecule and that molecule emits a photon rather than decomposing. We will show and quantify electron-induced fluorescence of several fluorophores in polymer films to mimic resist materials, and use this information to refine our proposed mechanism. Relationships between the molecular structure of fluorophores and fluorescent quantum yield may aid in the development of novel PAGs for EUV lithography.

Electron-electron Thomas peak in fast transfer ionization

International Nuclear Information System (INIS)

Tolmanov, S. G.; McGuire, J. H.

2000-01-01

''Thomas process'' is a name used for a family of singular two-step processes that can lead to electron transfer. The Thomas process of the ''second kind,'' occurring in reactions with both transfer and ionization, utilizes the e-e scattering in the second step, so this Thomas process requires the dynamics of the electron-electron interaction. We calculate numerically the second order element of an S matrix and corresponding cross sections for the transfer ionization process. We find that the position and shape of the Thomas peak depend on both electron-electron and the electron-nucleus interaction. Also the direct and exchange amplitudes are equal at the peak position. We test the peaking approximation used for transfer ionization. Our results can be compared to experimental results for p + +He→H+He 2+ +e - . (c) 2000 The American Physical Society

Descripción, distribución, anatomía, composición química y usos de Mimosa tenuiflora (Fabaceae-Mimosoideae en México

Directory of Open Access Journals (Sweden)

Sara Lucía Camargo-Ricalde

2000-12-01

Full Text Available A partir de una serie de catástrofes ocurridas en México durante la década de 1980, se popularizó el uso de la corteza del "tepescohuite" contra heridas y quemaduras de la piel. Los medios de comunicación masiva manejaron la escasa información hasta entonces conocida y desinformaron a la sociedad, propagando una serie de mitos alrededor de esta planta. El objetivo de este trabajo fue determinar la identidad taxonómica e investigar la distribución y anatomía de la corteza y de la madera de esta especie. También se investigaron sus usos actuales e históricos y se recopiló información sobre la farmacología y toxicidad de la corteza. Su identidad taxonómica se determina como Mimosa tenuiflora (Willd. Poir. (Fabaceae-Mimosoideae. Florece y fructifica de noviembre a junio y se localiza en México (estados de Oaxaca y Chiapas, Guatemala, Honduras, El Salvador, Nicaragua, Panamá, Colombia, Venezuela y Brasil, en altitudes de 0-1110 (-1520 msnm. En México se establece en selvas bajas, matorrales espinosos, en bosques de Pinus y de Pinus-Quercus, pudiendo formar matorrales casi puros de esta especie, así como a la orilla de caminos y en terrenos de cultivo en descanso o abandonados. Su distribución es agregada en los bosques y en las selvas y uniforme en los matorrales. Presenta una densidad promedio de 9 individuos por m², con 0.45 individuos de frecuencia por cuadrante y una cobertura promedio de 1.69 m²; además, tiene una gran amplitud de tolerancia a factores climáticos y edáficos, ratificando que es una especie de carácter oportunista y típicamente secundaria. Regionalmente, se utiliza como fuente de madera para combustible y postes para cercas, en medicina popular se usa contra heridas y quemaduras de la piel (infusión, polvo y/o pomada a partir de la corteza; además, se comercializan diversos productos como champúes, cremas, cápsulas, jabones, etc. La corteza es rugosa, de color café rojizo a grisácea, de textura

Electron Tree

DEFF Research Database (Denmark)

Appelt, Ane L; Rønde, Heidi S

2013-01-01

The photo shows a close-up of a Lichtenberg figure – popularly called an “electron tree” – produced in a cylinder of polymethyl methacrylate (PMMA). Electron trees are created by irradiating a suitable insulating material, in this case PMMA, with an intense high energy electron beam. Upon discharge......, during dielectric breakdown in the material, the electrons generate branching chains of fractures on leaving the PMMA, producing the tree pattern seen. To be able to create electron trees with a clinical linear accelerator, one needs to access the primary electron beam used for photon treatments. We...... appropriated a linac that was being decommissioned in our department and dismantled the head to circumvent the target and ion chambers. This is one of 24 electron trees produced before we had to stop the fun and allow the rest of the accelerator to be disassembled....

Electronic Raman response in electron-doped cuprate superconductors

International Nuclear Information System (INIS)

Geng Zhihao; Feng Shiping

2012-01-01

The electronic Raman response in the electron-doped cuprate superconductors is studied based on the t-t'-J model. It is shown that although the domelike shape of the doping dependent peak energy in the B 2g symmetry is a common feature for both electron-doped and hole-doped cuprate superconductors, there are pronounced deviations from a cubic response in the B 2g channel and a linear response in the B 2g channel for the electron-doped case in the low energy limit. It is also shown that these pronounced deviations are mainly caused by a nonmonotonic d-wave gap in the electron-doped cuprate superconductors.

Spectroscopy of electron irradiated polymers in electron microscope

International Nuclear Information System (INIS)

Faraj, S.H.; Salih, S.M.

1981-01-01

The damage induced by energetic electrons in the course of irradiation of polymers in a transmission electron microscope was investigated spectroscopically. Damage on the molecular level has been detected at very low exposure doses. These effects have been induced by electron doses less than that received by the specimen when it is situated at its usual place of the specimen stage in the electron microscope by a factor of 1,000. (author)

Electron spectroscopy in the fundamental process of electron-nucleus bremsstrahlung

International Nuclear Information System (INIS)

Hillenbrand, Pierre-Michel

2013-07-01

Within the scope of this thesis the fundamental process of electron-nucleus bremsstrahlung was studied in inverse kinematics at the Experimental Storage Ring ESR at GSI. For the system U 88+ + N 2 at 90 MeV/u it was shown, that by using inverse kinematics coincidence measurements between the scattered electron and the emitted photon can be performed for the case, in which the incoming electron transfers almost all of its kinetic energy onto the emitted photon. The sensitivity to the fundamental process could be achieved by measuring triple differential cross sections as a function of the emission angle of the photon and the scattered electron as well as the energy of the scattered electron. The optics of the magnetic electron spectrometer used were thoroughly revised and optimized to the experimental requirements. Analyzing different coincidences in this collision system, it was possible to determine the contributions to the electron distribution arising from radiative electron capture to the projectile continuum, nonradiative electron capture to the projectile continuum, and electron loss to the projectile continuum. The experimental results of each of these processes were compared to theoretical calculations. The electron spectra for the radiative and the nonradiative electron capture to continuum clearly reproduce the opposite asymmetry predicted by theory. Furthermore electron spectra for collisions of U 28+ with different gases were measured.

`Twisted' electrons

Science.gov (United States)

Larocque, Hugo; Kaminer, Ido; Grillo, Vincenzo; Leuchs, Gerd; Padgett, Miles J.; Boyd, Robert W.; Segev, Mordechai; Karimi, Ebrahim

2018-04-01

Electrons have played a significant role in the development of many fields of physics during the last century. The interest surrounding them mostly involved their wave-like features prescribed by the quantum theory. In particular, these features correctly predict the behaviour of electrons in various physical systems including atoms, molecules, solid-state materials, and even in free space. Ten years ago, new breakthroughs were made, arising from the new ability to bestow orbital angular momentum (OAM) to the wave function of electrons. This quantity, in conjunction with the electron's charge, results in an additional magnetic property. Owing to these features, OAM-carrying, or twisted, electrons can effectively interact with magnetic fields in unprecedented ways and have motivated materials scientists to find new methods for generating twisted electrons and measuring their OAM content. Here, we provide an overview of such techniques along with an introduction to the exciting dynamics of twisted electrons.

The electron

International Nuclear Information System (INIS)

Hestenes, David; Weingartshofer, Antonio

1991-01-01

The stupendous successes of the Dirac equation and quantum electro-dynamics have established the electron as the best understood of the fundamental constituents of matter. Nevertheless, physicists agree that the electron still has secrets to reveal. Moreover, powerful new theoretical and experimental tools for probing those secrets have been sharpened during the last decade. This workshop was organized to bring theorists and experimentalists together to discuss their common goal of knowing the electron. Present state and future prospects for progress toward that goal are here described. The theoretical papers encompass a wide range of views on the electron. Several argue that the 'Zitter-bewegung' is more than a mathematical peculiarity of the Dirac equation, that it may well be a real physical phenomenon and worthy of serious study, theoretically and experimentally. Besides generating the electron spin and magnetic moment, the 'Zitterbewegung' may be a vital clue to electron structure and self-interaction. Some of the papers employ a radical new formulation of the Dirac theory which reveals a hidden geo-metric structure in the theory that supports a 'Zitterbewegung' inter-pretation. For the last half century the properties of electrons have been probed primarily by scattering experiments at ever higher energies. Recently, however, two powerful new experimental techniques have emerged capable of giving alternative experimental views of the electron. First, techniques for confining single electrons for long term study have led to the most accurate measurements of the electron magnetic moment. Second, the interaction of high intensity laser fields with atoms and electrons have revealed striking new phenomena such as multiphoton ionization. refs.; figs.; tabs

Basic electronics

CERN Document Server

Holbrook, Harold D

1971-01-01

Basic Electronics is an elementary text designed for basic instruction in electricity and electronics. It gives emphasis on electronic emission and the vacuum tube and shows transistor circuits in parallel with electron tube circuits. This book also demonstrates how the transistor merely replaces the tube, with proper change of circuit constants as required. Many problems are presented at the end of each chapter. This book is comprised of 17 chapters and opens with an overview of electron theory, followed by a discussion on resistance, inductance, and capacitance, along with their effects on t

Family-specific vs. universal PCR primers for the study of mitochondrial DNA in plants

Directory of Open Access Journals (Sweden)

Aleksić Jelena M.

2016-01-01

Full Text Available Mitochondrial genomes (mtDNAs or mitogenomes of seed plants are characterized by a notoriously unstable organization on account of which available so-called universal or consensus primers may fail to fulfil their foreseen function - amplification of various mtDNA regions in a broad range of plant taxa. Thus, the primers developed for groups assumed to have similar organization of their mitogenomes, such as families, may facilitate a broader usage of more variable non-coding portions of these genomes in group members. Using in silico PCR method and six available complete mitogenomes of Fabaceae, it has been demonstrated that only three out of 36 published universal primer and three Medicago sativa-specific primer pairs that amplify various mtDNA regions are suitable for six representatives of the Fabaceae family upon minor modifications, and develop 21 Fabaceae-specific primer pairs for amplification of all 14 cis-splicing introns in genes of NADH subunits (nad genes which represent the most commonly used non-coding mtDNA regions in various studies in plants. Using the same method and six available complete mitogenomes of representatives of related families Cucurbitaceae, Euphorbiaceae and Rosaceae and a model plant, Arabidopsis thaliana, it has further been demonstrated that applicability of newly developed primer pairs for amplification of nad introns in more or less related taxa was dependent not only on species evolutionary distances but also on their genome sizes. A reported set of 24 primer pairs is a valuable resource which may facilitate a broader usage of mtDNA variability in future studies at both intra- and inter-specific levels in Fabaceae, which is the third largest family of flowering plants rarely studied at the mtDNA level, and in other more or less related taxa. [Projekat Ministarstva nauke Republike Srbije, br. 173005

Identification of putative and potential cross-reactive chickpea (Cicer arietinum) allergens through an in silico approach.

Science.gov (United States)

Kulkarni, Anuja; Ananthanarayan, Laxmi; Raman, Karthik

2013-12-01

Allergy has become a key cause of morbidity worldwide. Although many legumes (plants in the Fabaceae family) are healthy foods, they may have a number of allergenic proteins. A number of allergens have been identified and characterized in Fabaceae family, such as soybean and peanut, on the basis of biochemical and molecular biological approaches. However, our understanding of the allergens from chickpea (Cicer arietinum L.), belonging to this family, is very limited. In this study, we aimed to identify putative and cross-reactive allergens from Chickpea (C. arietinum) by means of in silico analysis of the chickpea protein sequences and allergens sequences from Fabaceae family. We retrieved known allergen sequences in Fabaceae family from the IUIS Allergen Nomenclature Database. We performed a protein BLAST (BLASTp) on these sequences to retrieve the similar sequences from chickpea. We further analyzed the retrieved chickpea sequences using a combination of in silico tools, to assess them for their allergenicity potential. Following this, we built structure models using FUGUE: Sequence-structure homology; these models generated by the recognition tool were viewed in Swiss-PDB viewer. Through this in silico approach, we identified seven novel putative allergens from chickpea proteome sequences on the basis of similarity of sequence, structure and physicochemical properties with the known reported legume allergens. Four out of seven putative allergens may also show cross reactivity with reported allergens since potential allergens had common sequence and structural features with the reported allergens. The in silico proteomic identification of the allergen proteins in chickpea provides a basis for future research on developing hypoallergenic foods containing chickpea. Such bioinformatics approaches, combined with experimental methodology, will help delineate an efficient and comprehensive approach to assess allergenicity and pave the way for a better understanding of

Electron-electron scattering and mobilities in semiconductors and quantum wells

International Nuclear Information System (INIS)

Lyo, S.K.

1986-01-01

The effect of electron-electron scattering on the mobility in semiconductors and semiconductor quantum wells is examined. A general exact formula is derived for the mobility, when the electron-electron collision rate is much faster than other scattering rates such as those by ionized impurities and phonons. In this limit, the transport relaxation rate is independent of the carrier's energy and contributions to the inverse mobility from individual scattering mechanism add up. The mobility becomes significantly reduced from its value in the absence of electron-electron scattering. When the collision rates are not necessarily dominated by electron-electron scattering, the mobility is calculated by the Kohler-Sondheimer variational method in the presence of ionized-impurity scattering and acoustic-phonon scattering in a nondegenerate two-dimensional quantum well

Modified Monte Carlo method for study of electron transport in degenerate electron gas in the presence of electron-electron interactions, application to graphene

Science.gov (United States)

Borowik, Piotr; Thobel, Jean-Luc; Adamowicz, Leszek

2017-07-01

Standard computational methods used to take account of the Pauli Exclusion Principle into Monte Carlo (MC) simulations of electron transport in semiconductors may give unphysical results in low field regime, where obtained electron distribution function takes values exceeding unity. Modified algorithms were already proposed and allow to correctly account for electron scattering on phonons or impurities. Present paper extends this approach and proposes improved simulation scheme allowing including Pauli exclusion principle for electron-electron (e-e) scattering into MC simulations. Simulations with significantly reduced computational cost recreate correct values of the electron distribution function. Proposed algorithm is applied to study transport properties of degenerate electrons in graphene with e-e interactions. This required adapting the treatment of e-e scattering in the case of linear band dispersion relation. Hence, this part of the simulation algorithm is described in details.

Attainment of Electron Beam Suitable for Medium Energy Electron Cooling

Energy Technology Data Exchange (ETDEWEB)

Seletskiy, Sergei M. [Univ. of Rochester, NY (United States)

2005-01-01

Electron cooling of charged particle beams is a well-established technique at electron energies of up to 300 keV. However, up to the present time the advance of electron cooling to the MeV-range energies has remained a purely theoretical possibility. The electron cooling project at Fermilab has recently demonstrated the ¯rst cooling of 8.9 GeV/c antiprotons in the Recycler ring, and therefore, has proved the validity of the idea of relativistic electron cool- ing. The Recycler Electron Cooler (REC) is the key component of the Teva- tron Run II luminosity upgrade project. Its performance depends critically on the quality of electron beam. A stable electron beam of 4.3 MeV car- rying 0.5 A of DC current is required. The beam suitable for the Recycler Electron Cooler must have an angular spread not exceeding 200 ¹rad. The full-scale prototype of the REC was designed, built and tested at Fermilab in the Wideband laboratory to study the feasibility of attaining the high-quality electron beam. In this thesis I describe various aspects of development of the Fermilab electron cooling system, and the techniques used to obtain the electron beam suitable for the cooling process. In particular I emphasize those aspects of the work for which I was principally responsible.

Microfluidic electronics.

Science.gov (United States)

Cheng, Shi; Wu, Zhigang

2012-08-21

Microfluidics, a field that has been well-established for several decades, has seen extensive applications in the areas of biology, chemistry, and medicine. However, it might be very hard to imagine how such soft microfluidic devices would be used in other areas, such as electronics, in which stiff, solid metals, insulators, and semiconductors have previously dominated. Very recently, things have radically changed. Taking advantage of native properties of microfluidics, advances in microfluidics-based electronics have shown great potential in numerous new appealing applications, e.g. bio-inspired devices, body-worn healthcare and medical sensing systems, and ergonomic units, in which conventional rigid, bulky electronics are facing insurmountable obstacles to fulfil the demand on comfortable user experience. Not only would the birth of microfluidic electronics contribute to both the microfluidics and electronics fields, but it may also shape the future of our daily life. Nevertheless, microfluidic electronics are still at a very early stage, and significant efforts in research and development are needed to advance this emerging field. The intention of this article is to review recent research outcomes in the field of microfluidic electronics, and address current technical challenges and issues. The outlook of future development in microfluidic electronic devices and systems, as well as new fabrication techniques, is also discussed. Moreover, the authors would like to inspire both the microfluidics and electronics communities to further exploit this newly-established field.

Electron-electron collision effects on the bremsstrahlung emission in Lorentzian plasmas

International Nuclear Information System (INIS)

Jung, Young-Dae; Kato, Daiji

2009-01-01

Electron-electron collision effects on the electron-ion bremsstrahlung process are investigated in Lorentzian plasmas. The effective electron-ion interaction potential is obtained by including the far-field terms caused by electron-electron collisions with an effective Debye length in Lorentzian plasmas. The bremsstrahlung radiation cross section is obtained as a function of the electron energy, photon energy, collision frequency, spectral index and Debye length using the Born approximation for the initial and final states of the projectile electron. It is shown that the non-Maxwellian character suppresses the bremsstrahlung radiation cross section. It is also shown that the electron-electron collision effect enhances the bremsstrahlung emission spectrum. In addition, the bremsstrahlung radiation cross section decreases with an increase in the plasma temperature.

Electron-photon and electron-electron interactions in the presence of strong electromagnetic fields

International Nuclear Information System (INIS)

Surzhykov, A.; Fritzsche, S.; Stoehlker, Th.

2010-01-01

During the last decade, photon emission from highly-charged, heavy ions has been in the focus of intense studies at the GSI accelerator and storage ring facility in Darmstadt. These studies have revealed unique information about the electron-electron and electron-photon interactions in the presence of extremely strong nuclear fields. Apart from the radiative electron capture processes, characteristic photon emission following collisional excitation of projectile ions has also attracted much interest. In this contribution, we summarize the recent theoretical studies on the production of excited ionic states and their subsequent radiative decay. We will pay special attention to the angular and polarization properties of Kα emission from helium-like ions produced by means of dielectronic recombination. The results obtained for this (resonant) capture process will be compared with the theoretical predictions for the characteristic X-rays following Coulomb excitation and radiative recombination of few-electron, heavy ions. Work is supported by Helmholtz Association and GSl under the project VH-NG--421. (author)

Sticker electronics

KAUST Repository

Hussain, Muhammad Mustafa

2017-09-08

Electronic stickers may be manufactured on flexible substrates (110, 120, 130) as layers and packaged together. The package may then have an adhesive applied to one side to provide capability for sticking the electronic devices to surfaces. The stickers can be wrappable, placed on surfaces, glued on walls or mirrors or wood or stone, and have electronics (112, 122, 132) which may or may not be ultrathin. Packaging for the electronic sticker can use polymer on cellulose manufacturing and/or three dimensional (3-D) printing. The electronic stickers may provide lighting capability, sensing capability, and/or recharging capabilities.

Electronic Commerce

Directory of Open Access Journals (Sweden)

Slavko Đerić

2016-12-01

Full Text Available Electronic commerce can be defined in different ways. Any definition helps to understand and explain that concept as better as possible.. Electronic commerce is a set of procedures and technologies that automate the tasks of financial transactions using electronic means. Also, according to some authors, electronic commerce is defined as a new concept, which is being developed and which includes process of buying and selling or exchanging products, services or information via computer networks, including the Internet. Electronic commerce is not limited just to buying and selling, but it also includes all pre-sales and after-sales ongoing activities along the supply chain. Introducing electronic commerce, using the Internet and Web services in business, realizes the way to a completely new type of economy - internet economy.

Observation of the two-electron cusp in atomic collisions. Evidence for strong electron-electron correlation

International Nuclear Information System (INIS)

Sarkadi, L.; Orban, A.

2007-01-01

Complete text of publication follows. In this report we present experimental data for a process when two electrons with velocity vectors equal to that of the projectile are emitted from collisions. By observing the two electron cusp the study of the threshold phenomenon for two-electron break-up is possible. It is a particularly interesting question whether the outgoing charged projectile can attract the two repulsing electrons so strongly that the two-electron cusp is formed. If it is so, a further question arises: Are the two electrons correlated in the final state as it is predicted by the Wannier theory? The experiments have been done at the 1 MeV VdG accelerator of ATOMKI using our TOF spectrometer. The first measurements clearly showed the formation of the two-electron cusp and signature of the electron correlation in 200 keV He 0 +He collisions. These promising results motivated us to carry out the experiment at 100 keV beam energy where the coincidence count rate is still reasonable but the energy resolution is better. For an acceptable data acquisition time we improved our data acquisition and data processing system for triple coincidence measurements. In Fig. 1a we present our measured relative fourfold differential cross section (FDCS) that shows strong electron correlation. For a comparison, in Fig. 1b we displayed the contour plot for uncorrelated electron pair emission. These latter data were synthesized artificially, generating the energies of the electron pairs from two independent double coincidence experiments. In both figures the distributions are characterized by two ridges. In Fig. 1b the ridges are perpendicular straight lines (E 1 = E 2 .13.6 eV). As a result of the correlation, the ridges in Fig. 1a are distorted in such a way that they have a joint straight-line section following the line E 1 + E 2 = 27.2 eV. This means that the electron pairs in the vicinity of the cusp maximum are emitted with a center of- mass velocity equal to that of

Protein characterization of protein bodies from cotyledons of Mucuna pruriens (L.) DC.

Science.gov (United States)

Bellani, Lorenza; Giglioni, Stefania; Muccifora, Simonetta

2013-03-01

Seeds of Mucuna pruriens (L.) DC. (Fabaceae) were analyzed for protein composition of protein bodies isolated from cotyledons. Protein bodies were successfully separated by Lympholyte and those of dry seeds, observed by scanning electron microscope, were elliptical or spherical in shape with a diameter of 5-12 μm. Protein content in dry seed protein bodies was 10.6 mg/g dry weight. Globulin was the largest protein fraction isolated (62.5 %), followed by albumin (18.3 %), glutelin (15.8 %) and prolamin (3.4 %). The prolamin fraction and high glutelin content are uncommon in legumes. SDS-PAGE of albumins, globulins, prolamins and glutelins provided different band numbers and molecular weights under reducing and non reducing conditions and suggested that the albumin fraction is rich in disulphide bonds.

Electronics and Information

Institute of Scientific and Technical Information of China (English)

无

2008-01-01

@@ Previously founded as CCPITMachinery and Electronics Sub-council and CCOIC Machinery and Electronics Chamber of Corn-merce in June, 1988, CCPIT Electronics Sub-Council and CCOIC Electronics Chamber of Commerce were established in May, 1993, and then renamed as CCPIT Electronics and Information Industry Sub-council and CCOIC Electronics and Infor-mation Industry Chamber of Commerce (CCPITECC) in September 1999.

Reproductive biology of Bowdichia virgilioides Kunth (Fabaceae) = Biologia reprodutiva de Bowdichia virgilioides Kunth (Fabaceae)

OpenAIRE

André Luiz Gomes da Silva; Samyra Ramos Chaves; Jéfferson Mesquita Brito

2011-01-01

The aim of this study was to investigate the reproductive biology of Bowdichia virgilioides in an area of Cerrado (Brazilian Savanna). The study was carried out in Chapadinha, State of Maranhão in northeastern Brazil. Bowdichia virgilioides has cornucopia flowering and annual pattern. Flowering occurred at the beginning of the dry season, between June and August; and fruiting in the middle of this season, between July and October. The anthesis of B. virgilioides is diurnal, and the main flowe...

Spontaneous and stimulated emission induced by an electron, electron bunch, and electron beam in a plasma

International Nuclear Information System (INIS)

Kuzelev, M V; Rukhadze, A A

2008-01-01

Two fundamental mechanisms - the Cherenkov effect and anomalous Doppler effect - underlying the emission by an electron during its superluminal motion in medium are considered. Cherenkov emission induced by a single electron and a small electron bunch is spontaneous. In the course of spontaneous Cherenkov emission, the translational motion of an electron is slowed down and the radiation energy grows linearly with time. As the number of radiating electrons increases, Cherenkov emission becomes stimulated. Stimulated Cherenkov emission represents a resonance beam instability. This emission process is accompanied by longitudinal electron bunching in the beam or by the breaking of an electron bunch into smaller bunches, in which case the radiation energy grows exponentially with time. In terms of the longitudinal size L e of the electron bunch there is a transition region λ e 0 -1 between the spontaneous and stimulated Cherenkov effects, where λ is the average radiation wavelength, and δ 0 is the dimensionless (in units of the radiation frequency) growth rate of the Cherenkov beam instability. The range to the left of this region is dominated by spontaneous emission, whereas the range to the right of this region is dominated by stimulated emission. In contrast to the Vavilov-Cherenkov effect, the anomalous Doppler effect should always (even for a single electron) be considered as stimulated, because it can only be explained by accounting for the reverse action of the radiation field on the moving electron. During stimulated emission in conditions where anomalous Doppler effect shows itself, an electron is slowed down and spins up; in this case, the radiation energy grows exponentially with time. (reviews of topical problems)

High perveance electron gun for the electron cooling system

International Nuclear Information System (INIS)

Korotaev, Yu.; Meshkov, I.; Petrov, A.; Sidorin, A.; Smirnov, A.; Syresin, E.; Titkova, I.

2000-01-01

The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 μA/V 3/2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual)

High perveance electron gun for the electron cooling system

CERN Document Server

Korotaev, Yu V; Petrov, A; Sidorin, A; Smirnov, A; Syresin, E M; Titkova, I

2000-01-01

The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 mu A/V sup 3 sup / sup 2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual).

Study of single-electron excitations by electron microscopy

International Nuclear Information System (INIS)

Craven, A.J.; Gibson, J.M.; Howie, A.; Spalding, D.R.

1978-01-01

The inelastic scattering of fast electrons by the excitation of L-shell electrons at a stacking fault in silicon has been studied with a scanning transmission electron microscope. It was found that the bright-field stacking fault contrast is preserved in the filtered L-shell-loss signal at 100 eV. This result is discussed in terms of the delocalization of the excitation mechanism. It is concluded that localization effects will typically become significant only for energy transfers greater than 1 keV from a fast electron of energy 80 keV. (author)

Syringe injectable electronics

Science.gov (United States)

Hong, Guosong; Zhou, Tao; Jin, Lihua; Duvvuri, Madhavi; Jiang, Zhe; Kruskal, Peter; Xie, Chong; Suo, Zhigang; Fang, Ying; Lieber, Charles M.

2015-01-01

Seamless and minimally-invasive three-dimensional (3D) interpenetration of electronics within artificial or natural structures could allow for continuous monitoring and manipulation of their properties. Flexible electronics provide a means for conforming electronics to non-planar surfaces, yet targeted delivery of flexible electronics to internal regions remains difficult. Here, we overcome this challenge by demonstrating syringe injection and subsequent unfolding of submicrometer-thick, centimeter-scale macroporous mesh electronics through needles with a diameter as small as 100 micrometers. Our results show that electronic components can be injected into man-made and biological cavities, as well as dense gels and tissue, with > 90% device yield. We demonstrate several applications of syringe injectable electronics as a general approach for interpenetrating flexible electronics with 3D structures, including (i) monitoring of internal mechanical strains in polymer cavities, (ii) tight integration and low chronic immunoreactivity with several distinct regions of the brain, and (iii) in vivo multiplexed neural recording. Moreover, syringe injection enables delivery of flexible electronics through a rigid shell, delivery of large volume flexible electronics that can fill internal cavities and co-injection of electronics with other materials into host structures, opening up unique applications for flexible electronics. PMID:26053995

Electronic Nose and Electronic Tongue

Science.gov (United States)

Bhattacharyya, Nabarun; Bandhopadhyay, Rajib

Human beings have five senses, namely, vision, hearing, touch, smell and taste. The sensors for vision, hearing and touch have been developed for several years. The need for sensors capable of mimicking the senses of smell and taste have been felt only recently in food industry, environmental monitoring and several industrial applications. In the ever-widening horizon of frontier research in the field of electronics and advanced computing, emergence of electronic nose (E-Nose) and electronic tongue (E-Tongue) have been drawing attention of scientists and technologists for more than a decade. By intelligent integration of multitudes of technologies like chemometrics, microelectronics and advanced soft computing, human olfaction has been successfully mimicked by such new techniques called machine olfaction (Pearce et al. 2002). But the very essence of such research and development efforts has centered on development of customized electronic nose and electronic tongue solutions specific to individual applications. In fact, research trends as of date clearly points to the fact that a machine olfaction system as versatile, universal and broadband as human nose and human tongue may not be feasible in the decades to come. But application specific solutions may definitely be demonstrated and commercialized by modulation in sensor design and fine-tuning the soft computing solutions. This chapter deals with theory, developments of E-Nose and E-Tongue technology and their applications. Also a succinct account of future trends of R&D efforts in this field with an objective of establishing co-relation between machine olfaction and human perception has been included.

Alkaloid profile, antibacterial and allelopathic activities of Lupinus jaimehintoniana B.L. Turner (Fabaceae

Directory of Open Access Journals (Sweden)

Ruiz-González Nancy

2012-01-01

Full Text Available Herein we describe some aspects of the ethnobotanical use and the first alkaloid profile of Lupinus jaimehintoniana, the 5 to 8 m high arboreous lupine. Five quinolizidine alkaloids identified as sparteine, 5,6-dehydrolupanine, lupanine, nuttalline, and d-thermopsine, were characterized by the respective elution order according to their electronic impact spectra, lupanine being the most abundant in the four different tissues analyzed. Simultaneously, an antibacterial assessment of the four corresponding crude methanolic extracts, as well as the four semi-purified alkaloids was performed on specific Escherichia coli and Agrobacterium tumefaciens strains. These experiments resulted in MIC ranges of 37-61 µg mL-1 and 130-146 µg mL-1, respectively. for both bacterial species. Finally, the allelopathic activity of these extracts on the germination of Lactuca sativa seeds was demonstrated to be in the range of 50-300 µg mL-1 for both semi-purified alkaloid and methanolic extracts.

A theory of electron baths: One-electron system dynamics

International Nuclear Information System (INIS)

McDowell, H.K.

1992-01-01

The second-quantized, many-electron, atomic, and molecular Hamiltonian is partitioned both by the identity or labeling of the spin orbitals and by the dynamics of the spin orbitals into a system coupled to a bath. The electron bath is treated by a molecular time scale generalized Langevin equation approach designed to include one-electron dynamics in the system dynamics. The bath is formulated as an equivalent chain of spin orbitals through the introduction of equivalent-chain annihilation and creation operators. Both the dynamics and the quantum grand canonical statistical properties of the electron bath are examined. Two versions for the statistical properties of the bath are pursued. Using a weak bath assumption, a bath statistical average is defined which allows one to achieve a reduced dynamics description of the electron system which is coupled to the electron bath. In a strong bath assumption effective Hamiltonians are obtained which reproduce the dynamics of the bath and which lead to the same results as found in the weak bath assumption. The effective (but exact) Hamiltonian is found to be a one-electron Hamiltonian. A reduced dynamics equation of motion for the system population matrix is derived and found to agree with a previous version. This equation of motion is useful for studying electron transfer in the system when coupled to an electron bath

Potential tree species for use in the restoration of unsanitary landfills.

Science.gov (United States)

Kim, Kee Dae; Lee, Eun Ju

2005-07-01

Given that they represent the most economical option for disposing of refuse, waste landfills are widespread in urban areas. However, landfills generate air and water pollution and require restoration for landscape development. A number of unsanitary waste landfills have caused severe environmental problems in developing countries. This study aimed to investigate the colonization status of different tree species on waste landfills to assess their potential for restoring unsanitary landfills in South Korea. Plot surveys were conducted using 10 x 10-m quadrats at seven waste landfill sites: Bunsuri, Dugiri, Hasanundong, Gomaeri, Kyongseodong, Mojeonri, and Shindaedong. We determined the height, diameter at breast height (DBH), and number of tree species in the plots, and enumerated all saplings landfills, we measured the distance from the presumed mother plant (i.e., the tallest black locust in a patch), height, and DBH of all individuals in black locust patches to determine patch structure. Robinia pseudoacacia, Salix koreensis, and Populus sieboldii formed canopy layers in the waste landfills. The basal area of black locust was 1.51 m(2)/ha, and this species had the highest number of saplings among all tree species. The diameter of the black locust patches ranged from 3.71 to 11.29 m. As the patch diameter increased, the number of regenerated saplings also tended to increase, albeit not significantly. Black locust invaded via bud banks and spread clonally in a concentric pattern across the landfills. This species grew well in the dry habitat of the landfills, and its growth rate was very high. Furthermore, black locust has the ability to fix nitrogen symbiotically; it is therefore considered a well-adapted species for waste landfills. Eleven woody species were selected for screening: Acer palmatum, Albizzia julibrissin, Buxus microphylla var. koreana, Ginkgo biloba, Hibiscus syriacus, Koelreuteria paniculata, Ligustrum obtusifolium, Liriodendron tulipifera, Pinus

Treatment of foods with 'soft-electrons' (low-energy electrons)

International Nuclear Information System (INIS)

Hayashi, Toru; Todoriki, Setsuko

2003-01-01

Electrons with energies of 300 keV or lower were defined as soft-electrons'. Soft-electrons can eradicate microorganisms residing on the surface of grains, pulses, spices, dehydrated vegetables, tea leaves and seeds, and reduce their microbial loads to levels lower than 10 CFU/g with little quality deterioration. Soft-electrons can inactivate insect pests infesting grains and pulses and inhibit sprouting of potatoes. (author)

Compact femtosecond electron diffractometer with 100 keV electron bunches approaching the single-electron pulse duration limit

International Nuclear Information System (INIS)

Waldecker, Lutz; Bertoni, Roman; Ernstorfer, Ralph

2015-01-01

We present the design and implementation of a highly compact femtosecond electron diffractometer working at electron energies up to 100 keV. We use a multi-body particle tracing code to simulate electron bunch propagation through the setup and to calculate pulse durations at the sample position. Our simulations show that electron bunches containing few thousands of electrons per bunch are only weakly broadened by space-charge effects and their pulse duration is thus close to the one of a single-electron wavepacket. With our compact setup, we can create electron bunches containing up to 5000 electrons with a pulse duration below 100 fs on the sample. We use the diffractometer to track the energy transfer from photoexcited electrons to the lattice in a thin film of titanium. This process takes place on the timescale of few-hundred femtoseconds and a fully equilibrated state is reached within 1 ps

Electron backscattering for process control in electron beam welding

International Nuclear Information System (INIS)

Ardenne, T. von; Panzer, S.

1983-01-01

A number of solutions to the automation of electron beam welding is presented. On the basis of electron backscattering a complex system of process control has been developed. It allows an enlarged imaging of the material's surface, improved adjustment of the beam focusing and definite focus positioning. Furthermore, both manual and automated positioning of the electron beam before and during the welding process has become possible. Monitoring of the welding process for meeting standard welding requirements can be achieved with the aid of a control quantity derived from the results of electronic evaluation of the high-frequency electron backscattering

Electron transfer reactions

CERN Document Server

Cannon, R D

2013-01-01

Electron Transfer Reactions deals with the mechanisms of electron transfer reactions between metal ions in solution, as well as the electron exchange between atoms or molecules in either the gaseous or solid state. The book is divided into three parts. Part 1 covers the electron transfer between atoms and molecules in the gas state. Part 2 tackles the reaction paths of oxidation states and binuclear intermediates, as well as the mechanisms of electron transfer. Part 3 discusses the theories and models of the electron transfer process; theories and experiments involving bridged electron transfe

Understand electronics

CERN Document Server

Bishop, Owen

2013-01-01

Understand Electronics provides a readable introduction to the exciting world of electronics for the student or enthusiast with little previous knowledge. The subject is treated with the minimum of mathematics and the book is extensively illustrated.This is an essential guide for the newcomer to electronics, and replaces the author's best-selling Beginner's Guide to Electronics.The step-by-step approach makes this book ideal for introductory courses such as the Intermediate GNVQ.

Electronic Commerce

OpenAIRE

Slavko Đerić

2016-01-01

Electronic commerce can be defined in different ways. Any definition helps to understand and explain that concept as better as possible.. Electronic commerce is a set of procedures and technologies that automate the tasks of financial transactions using electronic means. Also, according to some authors, electronic commerce is defined as a new concept, which is being developed and which includes process of buying and selling or exchanging products, services or information via computer networks...

Photon and electron collimator effects on electron output and abutting segments in energy modulated electron therapy

International Nuclear Information System (INIS)

Olofsson, Lennart; Karlsson, Magnus G.; Karlsson, Mikael

2005-01-01

In energy modulated electron therapy a large fraction of the segments will be arranged as abutting segments where inhomogeneities in segment matching regions must be kept as small as possible. Furthermore, the output variation between different segments should be minimized and must in all cases be well predicted. For electron therapy with add-on collimators, both the electron MLC (eMLC) and the photon MLC (xMLC) contribute to these effects when an xMLC tracking technique is utilized to reduce the x-ray induced leakage. Two add-on electron collimator geometries have been analyzed using Monte Carlo simulations: One isocentric eMLC geometry with an isocentric clearance of 35 cm and air or helium in the treatment head, and one conventional proximity geometry with a clearance of 5 cm and air in the treatment head. The electron fluence output for 22.5 MeV electrons is not significantly affected by the xMLC if the shielding margins are larger than 2-3 cm. For small field sizes and 9.6 MeV electrons, the isocentric design with helium in the treatment head or shielding margins larger than 3 cm is needed to avoid a reduced electron output. Dose inhomogeneity in the matching region of electron segments is, in general, small when collimator positions are adjusted to account for divergence in the field. The effect of xMLC tracking on the electron output can be made negligible while still obtaining a substantially reduced x-ray leakage contribution. Collimator scattering effects do not interfere significantly when abutting beam techniques are properly applied

Equation satisfied by electron-electron mutual Coulomb repulsion energy density functional

OpenAIRE

Joubert, Daniel P.

2011-01-01

The electron-electron mutual Coulomb repulsion energy density functional satisfies an equation that links functionals and functional derivatives at N-electron and (N-1)-electron densities for densities determined from the same adiabatic scaled external potential for the N-electron system.

Electronic Publishing.

Science.gov (United States)

Lancaster, F. W.

1989-01-01

Describes various stages involved in the applications of electronic media to the publishing industry. Highlights include computer typesetting, or photocomposition; machine-readable databases; the distribution of publications in electronic form; computer conferencing and electronic mail; collaborative authorship; hypertext; hypermedia publications;…

Syringe-injectable electronics.

Science.gov (United States)

Liu, Jia; Fu, Tian-Ming; Cheng, Zengguang; Hong, Guosong; Zhou, Tao; Jin, Lihua; Duvvuri, Madhavi; Jiang, Zhe; Kruskal, Peter; Xie, Chong; Suo, Zhigang; Fang, Ying; Lieber, Charles M

2015-07-01

Seamless and minimally invasive three-dimensional interpenetration of electronics within artificial or natural structures could allow for continuous monitoring and manipulation of their properties. Flexible electronics provide a means for conforming electronics to non-planar surfaces, yet targeted delivery of flexible electronics to internal regions remains difficult. Here, we overcome this challenge by demonstrating the syringe injection (and subsequent unfolding) of sub-micrometre-thick, centimetre-scale macroporous mesh electronics through needles with a diameter as small as 100 μm. Our results show that electronic components can be injected into man-made and biological cavities, as well as dense gels and tissue, with >90% device yield. We demonstrate several applications of syringe-injectable electronics as a general approach for interpenetrating flexible electronics with three-dimensional structures, including (1) monitoring internal mechanical strains in polymer cavities, (2) tight integration and low chronic immunoreactivity with several distinct regions of the brain, and (3) in vivo multiplexed neural recording. Moreover, syringe injection enables the delivery of flexible electronics through a rigid shell, the delivery of large-volume flexible electronics that can fill internal cavities, and co-injection of electronics with other materials into host structures, opening up unique applications for flexible electronics.

Electronic excitation of Na atom by electron impact

International Nuclear Information System (INIS)

Bielschowsky, C.E.; Souza, G.G.B. de; Lucas, C.A.; Nogueira, J.C.

1988-01-01

Electronic excitation of the 3s-3p transition in the Na atom was studied by intermediate energy electron impact spectroscopy. Differential Cross Sections (DCS) and Generalized Oscillator Strenghts (GOS) were determined experimentally for 1 KeV electrons. Theoretical results within the First Born Approximation as well as Glauber theory, were also performed. (A.C.A.S.) [pt

Highly efficient electron gun with a single-atom electron source

International Nuclear Information System (INIS)

Ishikawa, Tsuyoshi; Urata, Tomohiro; Cho, Boklae; Rokuta, Eiji; Oshima, Chuhei; Terui, Yoshinori; Saito, Hidekazu; Yonezawa, Akira; Tsong, Tien T.

2007-01-01

The authors have demonstrated highly collimated electron-beam emission from a practical electron gun with a single-atom electron source; ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources such as a cold field emission gun and a Zr/O/W Schottky gun. At the pressure of less than 1x10 -9 Pa, the authors observed stable emission of 20 nA, which generates the specimen current of 5 pA required for scanning electron microscopes

Electron-electron interaction in p-SiGe/Ge quantum wells

International Nuclear Information System (INIS)

Roessner, Benjamin; Kaenel, Hans von; Chrastina, Daniel; Isella, Giovanni; Batlogg, Bertram

2005-01-01

The temperature dependent magnetoresistance of high mobility p-SiGe/Ge quantum wells is studied with hole densities ranging from 1.7 to 5.9 x 10 11 cm -2 . At magnetic fields below the onset of quantum oscillations that reflect the high mobility values (up to 75000 cm 2 /Vs), we observe the clear signatures of electron-electron interaction. We compare our experiment with the theory of electron-electron interaction including the Zeeman band splitting. The observed magnetoresistance is well explained as a superposition of band structure induced positive magnetoresistance and the negative magntoresistance due to the electron-electron interaction effect

Electron-electron interactions in disordered systems

CERN Document Server

Efros, AL

1985-01-01

``Electron-Electron Interactions in Disordered Systems'' deals with the interplay of disorder and the Coulomb interaction. Prominent experts give state-of-the-art reviews of the theoretical and experimental work in this field and make it clear that the interplay of the two effects is essential, especially in low-dimensional systems.

Narrow electron injector for ballistic electron spectroscopy

International Nuclear Information System (INIS)

Kast, M.; Pacher, C.; Strasser, G.; Gornik, E.

2001-01-01

A three-terminal hot electron transistor is used to measure the normal energy distribution of ballistic electrons generated by an electron injector utilizing an improved injector design. A triple barrier resonant tunneling diode with a rectangular transmission function acts as a narrow (1 meV) energy filter. An asymmetric energy distribution with its maximum on the high-energy side with a full width at half maximum of ΔE inj =10 meV is derived. [copyright] 2001 American Institute of Physics

Temperature Dependence of the Spin-Hall Conductivity of a Two-Dimensional Impure Rashba Electron Gas in the Presence of Electron-Phonon and Electron-Electron Interactions

Science.gov (United States)

Yavari, H.; Mokhtari, M.; Bayervand, A.

2015-03-01

Based on Kubo's linear response formalism, temperature dependence of the spin-Hall conductivity of a two-dimensional impure (magnetic and nonmagnetic impurities) Rashba electron gas in the presence of electron-electron and electron-phonon interactions is analyzed theoretically. We will show that the temperature dependence of the spin-Hall conductivity is determined by the relaxation rates due to these interactions. At low temperature, the elastic lifetimes ( and are determined by magnetic and nonmagnetic impurity concentrations which are independent of the temperature, while the inelastic lifetimes ( and related to the electron-electron and electron-phonon interactions, decrease when the temperature increases. We will also show that since the spin-Hall conductivity is sensitive to temperature, we can distinguish the intrinsic and extrinsic contributions.

Analytical local electron-electron interaction model potentials for atoms

International Nuclear Information System (INIS)

Neugebauer, Johannes; Reiher, Markus; Hinze, Juergen

2002-01-01

Analytical local potentials for modeling the electron-electron interaction in an atom reduce significantly the computational effort in electronic structure calculations. The development of such potentials has a long history, but some promising ideas have not yet been taken into account for further improvements. We determine a local electron-electron interaction potential akin to those suggested by Green et al. [Phys. Rev. 184, 1 (1969)], which are widely used in atom-ion scattering calculations, electron-capture processes, and electronic structure calculations. Generalized Yukawa-type model potentials are introduced. This leads, however, to shell-dependent local potentials, because the origin behavior of such potentials is different for different shells as has been explicated analytically [J. Neugebauer, M. Reiher, and J. Hinze, Phys. Rev. A 65, 032518 (2002)]. It is found that the parameters that characterize these local potentials can be interpolated and extrapolated reliably for different nuclear charges and different numbers of electrons. The analytical behavior of the corresponding localized Hartree-Fock potentials at the origin and at long distances is utilized in order to reduce the number of fit parameters. It turns out that the shell-dependent form of Green's potential, which we also derive, yields results of comparable accuracy using only one shell-dependent parameter

Extracting electron backscattering coefficients from backscattered electron micrographs

International Nuclear Information System (INIS)

Zupanic, F.

2010-01-01

Electron backscattering micrographs possess the so-called Z-contrast, carrying information about the chemical compositions of phases present in microstructures. The intensity at a particular point in the backscattered electron micrograph is proportional to the signal detected at a corresponding point in the scan raster, which is, in turn, proportional to the electron backscattering coefficient of a phase at that point. This article introduces a simple method for extracting the electron backscattering coefficients of phases present in the microstructure, from the backscattered electron micrographs. This method is able to convert the micrograph's greyscale to the backscattering-coefficient-scale. The prerequisite involves the known backscattering coefficients for two phases in the micrograph. In this way, backscattering coefficients of other phases can be determined. The method is unable to determine the chemical compositions of phases or the presence of an element only from analysing the backscattered electron micrograph. Nevertheless, this method was found to be very powerful when combined with energy dispersive spectroscopy, and the calculations of backscattering coefficients. - Research Highlights: →A simple method for extracting the electron backscattering coefficients →The prerequisite is known backscattering coefficients for two phases →The information is complementary to the EDS-results. →This method is especially useful when a phase contains a light element (H, Li, Be, and B)

PIC simulation of the electron-ion collision effects on suprathermal electrons

International Nuclear Information System (INIS)

Wu Yanqing; Han Shensheng

2000-01-01

The generation and transportation of suprathermal electrons are important to both traditional ICF scheme and 'Fast Ignition' scheme. The author discusses the effects of electron-ion collision on the generation and transportation of the suprathermal electrons by parametric instability. It indicates that the weak electron-ion term in the PIC simulation results in the enhancement of the collisional absorption and increase of the hot electron temperature and reduction in the maximum electrostatic field amplitude while wave breaking. Therefore the energy and distribution of the suprathermal electrons are changed. They are distributed more close to the phase velocity of the electrostatic wave than the case without electron-ion collision term. The electron-ion collision enhances the self-consistent field and impedes the suprathermal electron transportation. These factors also reduce the suprathermal electron energy. In addition, the authors discuss the effect of initial condition on PIC simulation to ensure that the results are correct

Spin Relaxation in GaAs: Importance of Electron-Electron Interactions

Directory of Open Access Journals (Sweden)

Gionni Marchetti

2014-04-01

Full Text Available We study spin relaxation in n-type bulk GaAs, due to the Dyakonov–Perel mechanism, using ensemble Monte Carlo methods. Our results confirm that spin relaxation time increases with the electronic density in the regime of moderate electronic concentrations and high temperature. We show that the electron-electron scattering in the non-degenerate regime significantly slows down spin relaxation. This result supports predictions by Glazov and Ivchenko. Most importantly, our findings highlight the importance of many-body interactions for spin dynamics: we show that only by properly taking into account electron-electron interactions within the simulations, results for the spin relaxation time—with respect to both electron density and temperature—will reach good quantitative agreement with corresponding experimental data. Our calculations contain no fitting parameters.

Secondary mineralization in carious lesions of human dentin. Electron-probe, electron microscope, and electron diffraction studies

Energy Technology Data Exchange (ETDEWEB)

Ogiwara, H [Tokyo Dental Coll. (Japan)

1975-02-01

Dentinal carious lesions having a remineralized surface layer were studied by means electron-probe microanalysis, electron microscopy, electron diffraction. As the results of electron-probe study, F, Mg, and Na were found to be distributed mainly in the remineralized surface layer and S in the decalcified region where decreases in Ca, P, and Mg concentration were usually observed. The decrease in Mg concentration always started earlier than that of Ca and P concentration. Electron microscope and electron diffraction studies revealed that apatic crystals in the remineralized surface layer were much larger than those in the intact dentin. Although they were less conspicuous, crystals in the decalcified region also were larger than those in the intact region. Dentinal tubules, occluded by many crystals, were frequently seen during the observations. Crystals in the tubules varied in morphology, showing granular, needle, rhomboid, and tabular shapes. By means of electron diffraction, the granular- or needle-shaped crystals were identified as apatite and the rhomboid-shaped crystals as whitlockite. Some of the tabular-shaped crystals appeared to be cotacalcium phosphate.

Electronic components

CERN Document Server

Colwell, Morris A

1976-01-01

Electronic Components provides a basic grounding in the practical aspects of using and selecting electronics components. The book describes the basic requirements needed to start practical work on electronic equipment, resistors and potentiometers, capacitance, and inductors and transformers. The text discusses semiconductor devices such as diodes, thyristors and triacs, transistors and heat sinks, logic and linear integrated circuits (I.C.s) and electromechanical devices. Common abbreviations applied to components are provided. Constructors and electronics engineers will find the book useful

Ion- and electron-acoustic solitons in two-electron temperature space plasmas

International Nuclear Information System (INIS)

Lakhina, G. S.; Kakad, A. P.; Singh, S. V.; Verheest, F.

2008-01-01

Properties of ion- and electron-acoustic solitons are investigated in an unmagnetized multicomponent plasma system consisting of cold and hot electrons and hot ions using the Sagdeev pseudopotential technique. The analysis is based on fluid equations and the Poisson equation. Solitary wave solutions are found when the Mach numbers exceed some critical values. The critical Mach numbers for the ion-acoustic solitons are found to be smaller than those for electron-acoustic solitons for a given set of plasma parameters. The critical Mach numbers of ion-acoustic solitons increase with the increase of hot electron temperature and the decrease of cold electron density. On the other hand, the critical Mach numbers of electron-acoustic solitons increase with the increase of the cold electron density as well as the hot electron temperature. The ion-acoustic solitons have positive potentials for the parameters considered. However, the electron-acoustic solitons have positive or negative potentials depending whether the fractional cold electron density with respect to the ion density is greater or less than a certain critical value. Further, the amplitudes of both the ion- and electron-acoustic solitons increase with the increase of the hot electron temperature. Possible application of this model to electrostatic solitary waves observed on the auroral field lines by the Viking spacecraft is discussed

Caracterização de solos de duas formações de restinga e sua influência na constituição química foliar de Passiflora mucronata Lam. (Passifloraceaee Canavalia rosea (Sw. DC. (Fabaceae Soil characterization of two restinga formations and its influence on leaf chemistry in Passiflora mucronata Lam. (Passifloraceae and Canavalia rosea (Sw. DC. (Fabaceae

Directory of Open Access Journals (Sweden)

Jehová Lourenço Junior

2009-03-01

Full Text Available As hipóteses sobre o posicionamento das formações de restinga são diversas sendo o gradiente salino e a fertilidade do solo as mais difundidas. Buscando elucidar essas questões, foram analisadas as propriedades dos solos das formações psamófila-reptante (FPR e Palmae (FP bem como a constituição química foliar de C. rosea (Sw. DC. restrita à FPR e P. mucronata Lam., na FP. O solo da FP destacou-se pela maior fertilidade. Maiores teores dos metais Fe, Zn e ISNa foram encontrados em solos da FPR. Não foi detectada a presença de Al nas duas formações. O pH dos solos é alcalino sem diferenças entre as duas formações. Os elementos químicos P, S, Cu e Zn acumulam-se em maiores concentrações em folhas de P. mucronata. C. rosea destacou-se pelos maiores teores foliares de N, Fe e B. Essa Fabaceae mostrou valores superiores do fator de concentração para o Ca, Mg, Fe, Cu e B enquanto que P. mucronata, para o P e Zn. Os resultados obtidos sugerem que as características pedológicas têm papel chave no estabelecimento de C. rosea na FPRe de P. mucronata na FP.Hypotheses as to the position of restinga formations are many, the most widespread being the salinity gradient and soil fertility. In order to elucidate these questions, soil properties of the creeping psammophyte (CPF and Palmae formations (PF as well as leaf chemistry of C. rosea (Sw. DC. restricted to the former and P. mucronata Lam. in the latter were analyzed. The PF soil was more fertile. Higher content of Fe, Zn and ISNa was found in CPF soil. The presence of Al in these two formations was not detected. Soil pH is alkaline, with no difference found between the two formations. The chemical elements P, S, Cu and Zn accumulate in greater concentrations in P. mucronata leaves. C. rosea was distinguished by a higher leaf content of N, Fe and B. This legume showed greater factor of concentration values for Ca, Mg, Fe, Cu and B whereas P. mucronata, for P and Zn. The results

Diffusive scattering of electrons by electron holes around injection fronts

Science.gov (United States)

Vasko, I. Y.; Agapitov, O. V.; Mozer, F. S.; Artemyev, A. V.; Krasnoselskikh, V. V.; Bonnell, J. W.

2017-03-01

Van Allen Probes have detected nonlinear electrostatic spikes around injection fronts in the outer radiation belt. These spikes include electron holes (EH), double layers, and more complicated solitary waves. We show that EHs can efficiently scatter electrons due to their substantial transverse electric fields. Although the electron scattering driven by EHs is diffusive, it cannot be evaluated via the standard quasi-linear theory. We derive analytical formulas describing local electron scattering by a single EH and verify them via test particle simulations. We show that the most efficiently scattered are gyroresonant electrons (crossing EH on a time scale comparable to the local electron gyroperiod). We compute bounce-averaged diffusion coefficients and demonstrate their dependence on the EH spatial distribution (latitudinal extent and spatial filling factor) and individual EH parameters (amplitude of electrostatic potential, velocity, and spatial scales). We show that EHs can drive pitch angle scattering of ≲5 keV electrons at rates 10-2-10-4 s-1 and, hence, can contribute to electron losses and conjugated diffuse aurora brightenings. The momentum and pitch angle scattering rates can be comparable, so that EHs can also provide efficient electron heating. The scattering rates driven by EHs at L shells L ˜ 5-8 are comparable to those due to chorus waves and may exceed those due to electron cyclotron harmonics.

Pseudogap in the Eliashberg approach based on electron-phonon and electron-electron-phonon interaction

Energy Technology Data Exchange (ETDEWEB)

Szczesniak, R. [Institute of Physics, Czestochowa University of Technology (Poland); Institute of Physics, Jan Dlugosz University in Czestochowa (Poland); Durajski, A.P.; Duda, A.M. [Institute of Physics, Czestochowa University of Technology (Poland)

2017-04-15

The properties of the superconducting and the anomalous normal state were described by using the Eliashberg method. The pairing mechanism was reproduced with the help of the Hamiltonian, which models the electron-phonon and the electron-electron-phonon interaction (EEPh). The set of the Eliashberg equations, which determines the order parameter function (φ), the wave function renormalization factor (Z), and the energy shift function (χ), was derived. It was proven that for the sufficiently large values of the EEPh potential, the doping dependence of the order parameter (φ/Z) has the analogous course to that observed experimentally in cuprates. The energy gap in the electron density of states is induced by Z and χ - the contribution from φ is negligible. The electron density of states possesses the characteristic asymmetric form and the pseudogap is observed above the critical temperature. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Carbon Nanotube Electron Gun

Science.gov (United States)

Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)

2013-01-01

An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.

Molecular electron affinities

International Nuclear Information System (INIS)

Fukuda, E.K.

1983-01-01

Molecular electron affinities have historically been difficult quantities to measure accurately. These difficulties arise from differences in structure between the ion and neutral as well as the existence of excited negative ion states. To circumvent these problems, relative electron affinities were determined in this dissertation by studying equilibrium electron transfer reactions using a pulsed ion cyclotron resonance (ICR) spectrometer. Direct measurement of ion and neutral concentrations for reactions of the general type, A - + B = B - + A, allow calculation of the equilibrium constant and, therefore, the free energy change. The free energy difference is related to the difference in electron affinities between A and B. A relative electron affinity scale covering a range of about 45 kcal/mol was constructed with various substituted p-benzoquinones, nitrobenzenes, anhydrides, and benzophenones. To assign absolute electron affinities, various species with accurately known electron affinities are tied to the scale via ion-cyclotron double resonance bracketing techniques. After the relative scale is anchored to these species with well-known electron affinities, the scale is then used as a check on other electron affinity values as well as generating new electron affinity values. Many discrepancies were found between the electron affinities measured using the ICR technique and previous literature determinations

Nonambipolar electron source

International Nuclear Information System (INIS)

Longmier, B.; Baalrud, S.; Hershkowitz, N.

2006-01-01

A radio frequency (rf) plasma-based electron source that does not rely on electron emission at a cathode surface has been constructed. All of the random electron flux incident on an exit aperture is extracted through an electron sheath resulting in total nonambipolar flow within the device when the ratio of the ion loss area to the electron loss area is approximately equal to the square root of the ratio of the ion mass to the electron mass, and the ion sheath potential drop at the chamber walls is much larger than T e /e. The nonambipolar electron source (NES) has an axisymmetric magnetic field of 100 G at the extraction aperture that results in a uniform plasma potential across the aperture, allowing the extraction of all the incident electron flux without the use of grids. A prototype NES has produced 15 A of continuous electron current, using 15 SCCM (SCCM denotes cubic centimeter per minute at STP) Ar, 1200 W rf power at 13.56 MHz, and 6 times gas utilization. Alternatively 8 A of electron current can be produced, using 3 SCCM Ar at 1200 W rf and 20 times gas utilization. NES could replace hollow cathode electron sources in a wide variety of applications

Electron-plasmon model in the electron liquid theory

Directory of Open Access Journals (Sweden)

M.V.Vavrukh

2005-01-01

Full Text Available Here we propose an accurate approach to the description of the electron liquid model in the electron and plasmon terms. Our ideas in the present paper are close to the conception of the collective variables which was developed in the papers of Bohm and Pines. However we use another body of mathematics in the transition to the expanded space of variable particles and plasmons realized by the transition operator. It is evident that in the Random Phase Approximation (RPA, the model which consists of two interactive subsystems of electrons and plasmons is equivalent to the electron liquid model with Coulomb interaction.

Polymer electronics

CERN Document Server

Hsin-Fei, Meng

2013-01-01

Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

Environ: E00627 [KEGG MEDICUS

Lifescience Database Archive (English)

Full Text Available E00627 Amblytropis multiflora root or herb Crude drug ... Amblytropis multiflora, Amb...lytropis [TAX:324290] ... Fabaceae (pea family) Amblytropis multiflora root or herb with root (dried) ...

A direct electron detector for time-resolved MeV electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Vecchione, T.; Denes, P.; Jobe, R. K.; Johnson, I. J.; Joseph, J. M.; Li, R. K.; Perazzo, A.; Shen, X.; Wang, X. J.; Weathersby, S. P.; Yang, J.; Zhang, D.

2017-03-01

The introduction of direct electron detectors enabled the structural biology revolution of cryogenic electron microscopy. Direct electron detectors are now expected to have a similarly dramatic impact on time-resolved MeV electron microscopy, particularly by enabling both spatial and temporal jitter correction. Here we report on the commissioning of a direct electron detector for time-resolved MeV electron microscopy. The direct electron detector demonstrated MeV single electron sensitivity and is capable of recording megapixel images at 180 Hz. The detector has a 15-bit dynamic range, better than 30-μmμm spatial resolution and less than 20 analogue-to-digital converter count RMS pixel noise. The unique capabilities of the direct electron detector and the data analysis required to take advantage of these capabilities are presented. The technical challenges associated with generating and processing large amounts of data are also discussed.

Coherent Electron Focussing in a Two-Dimensional Electron Gas.

NARCIS (Netherlands)

Houten, H. van; Wees, B.J. van; Mooij, J.E.; Beenakker, C.W.J.; Williamson, J.G.; Foxon, C.T.

1988-01-01

The first experimental realization of ballistic point contacts in a two-dimensional electron gas for the study of transverse electron focussing by a magnetic field is reported. Multiple peaks associated with skipping orbits of electrons reflected specularly by the channel boundary are observed. At

A study on the secondary electrons in a clinical electron beam

International Nuclear Information System (INIS)

Krithivas, G.; Rao, S.N.

1989-01-01

The central axis dose of a 12 MeV clinical electron beam is investigated in terms of an axial component due to primary electrons in the central ray and a lateral component due to secondary electrons originating from multiple scattering of electrons in the off-axis rays. To this effect secondary electron fluence measurements in a polystyrene medium irradiated with a collimated beam are made with a sensitive diode detector. This leads to a construction of secondary electron depth-dose profiles for beam sizes of diameters ranging from 1.7 to 17.4 cm. The results indicate that the lateral electrons account for 25% of the dose in the therapeutic region. For these electrons, the depth of dose maximum is correlated with diffusion depth and maximum lateral excursion in the medium. Dose component due to backscatter electrons at depths is also investigated using a thin-window parallel-plate ion chamber. The role of lateral and backscatter electrons in characterising central axis per cent depth-dose is discussed. (author)

Electronics for dummies

CERN Document Server

Shamieh

2015-01-01

Explore the basic concepts of electronics, build your electronics workbench, and begin creating fun electronics projects right away! Electronics For Dummies, 3rd Edition is your guide to the world of electronics. Spanning circuitry, wiring, robotics, transmitters, amplifiers, and more, this book demystifies electricity basics and beyond. The third edition offers new content revised to reflect the latest advancements in the electronics field, and it offers full color project examples to spark your creativity and inspire you to put your new skills to use! Packed with projects that can be comple

Electron holography

CERN Document Server

Tonomura, Akira

1993-01-01

Holography was devised for breaking through the resolution limit of electron microscopes The advent of a "coherent" field emission electron beam has enabled the use of Electron Holography in various areas of magnetic domain structures observation, fluxon observation in superconductors, and fundamental experiments in physics which have been inaccessible using other techniques After examining the fundamentals of electron holography and its applications to the afore mentioned fields, a detailed discussion of the Aharonov-Bohm effect and the related experiments is presented Many photographs and illustrations are included to elucidate the text

Comprehensive analysis of electron correlations in three-electron atoms

International Nuclear Information System (INIS)

Morishita, T.; Lin, C.D.

1999-01-01

We study the electron correlations in singly, doubly, and triply excited states of a three-electron atom. While electron correlation in general is weak for singly excited states, correlation plays major roles in determining the characteristics of doubly and triply excited states. Using the adiabatic approximation in hyperspherical coordinates, we show that the distinction between singly, doubly, and triply excited states is determined by the radial correlations, while finer distinctions within doubly or triply excited states lie in the angular correlations. Partial projections of the body-fixed frame wave functions are used to demonstrate the characteristic nodal surfaces which provide clues to the energy ordering of the states. We show that doubly excited states of a three-electron atom exhibit correlations that are similar to the doubly excited states of a two-electron atom. For the triply excited states, we show that the motion of the three electrons resemble approximately that of a symmetric top. copyright 1999 The American Physical Society

Advanced electron beam techniques

International Nuclear Information System (INIS)

Hirotsu, Yoshihiko; Yoshida, Yoichi

2007-01-01

After 100 years from the time of discovery of electron, we now have many applications of electron beam in science and technology. In this report, we review two important applications of electron beam: electron microscopy and pulsed-electron beam. Advanced electron microscopy techniques to investigate atomic and electronic structures, and pulsed-electron beam for investigating time-resolved structural change are described. (author)

Effects of electron-electron interactions on electronic transport in disordered systems

International Nuclear Information System (INIS)

Foley, Simon Timothy

2002-01-01

This thesis is concerned with the role of electron-electron interactions on electronic transport in disordered systems. We first consider a novel non-linear sigma model in order to microscopically treat the effects of disorder and electronic interaction. We successfully reproduce the perturbative results for the zero-bias anomaly and the interaction correction to the conductivity in a weakly disordered system, and discuss possible directions for future work. Secondly we consider the fluctuations of the dephasing rate for a closed diffusive and quantum dot system. Using the Keldysh technique we derive an expression for the inelastic scattering rate with which we self-consistently obtain the fluctuations in the dephasing rate. For the diffusive regime we find the relative fluctuations is given by F ∼ (L φ /L) 2 /g 2 , where g is the dimensionless conductance, L φ is the dephasing length and L is the sample size. For the quantum dot regime we find a perturbative divergence due to the presence of the zero mode. By mapping divergent diagrams to those for the two-level correlation function, we conjecture the existence of an exact relation between the two. Finally we discuss the consequences of this relation. (author)

Characteristics of trapped electrons and electron traps in single crystals

International Nuclear Information System (INIS)

Budzinski, E.E.; Potter, W.R.; Potienko, G.; Box, H.C.

1979-01-01

Two additional carbohydrates are reported whose crystal structures trap electrons intermolecularly in single crystals x irradiated at low temperature, namely sucrose and rhamnose. Five carbohydrate and polyhydroxy compounds are now known which exhibit this phenomenon. The following characteristics of the phenomenon were investigated: (1) the hyperfine couplings of the electron with protons of the polarized hydroxy groups forming the trap; (2) the distances between these protons and the trapped electron; (3) the spin density of the electron at the protons and (4) the relative stabilities of the electron trapped in various crystal structures

Electron-electron scattering in linear transport in two-dimensional systems

DEFF Research Database (Denmark)

Hu, Ben Yu-Kuang; Flensberg, Karsten

1996-01-01

We describe a method for numerically incorporating electron-electron scattering in quantum wells for small deviations of the distribution function from equilibrium, within the framework of the Boltzmann equation. For a given temperature T and density n, a symmetric matrix needs to be evaluated only...... once, and henceforth it can be used to describe electron-electron scattering in any Boltzmann equation linear-response calculation for that particular T and n. Using this method, we calculate the distribution function and mobility for electrons in a quantum well, including full finite...

Terahertz Plasma Waves in Two Dimensional Quantum Electron Gas with Electron Scattering

International Nuclear Information System (INIS)

Zhang Liping

2015-01-01

We investigate the Terahertz (THz) plasma waves in a two-dimensional (2D) electron gas in a nanometer field effect transistor (FET) with quantum effects, the electron scattering, the thermal motion of electrons and electron exchange-correlation. We find that, while the electron scattering, the wave number along y direction and the electron exchange-correlation suppress the radiation power, but the thermal motion of electrons and the quantum effects can amplify the radiation power. The radiation frequency decreases with electron exchange-correlation contributions, but increases with quantum effects, the wave number along y direction and thermal motion of electrons. It is worth mentioning that the electron scattering has scarce influence on the radiation frequency. These properties could be of great help to the realization of practical THz plasma oscillations in nanometer FET. (paper)

Oblique electron cyclotron emission for electron distribution studies (invited)

International Nuclear Information System (INIS)

Preische, S.; Efthimion, P.C.; Kaye, S.M.

1997-01-01

Electron cyclotron emission (ECE) at an oblique angle to the magnetic field provides a means of probing the electron distribution function both in energy and physical space through changes in and constraints on the relativistic electron cyclotron resonance condition. Diagnostics based on this Doppler shifted resonance are able to study a variety of electron distributions through changes in the location of the resonance in physical or energy space accomplished by changes in the viewing angle and frequency, and the magnetic field. For the case of observation across a changing magnetic field, such as across the tokamak midplane, the constraint on the resonance condition for real solutions to the dispersion relation can constrain the physical location of optically thin emission. A new Oblique ECE diagnostic was installed and operated on the PBX-M tokamak for the study of energetic electrons during lower hybrid current drive. It has a view 33 degree with respect to perpendicular in the tokamak midplane, receives second harmonic X-mode emission, and is constrained to receive single pass emission by SiC viewing dumps on the tokamak walls. Spatial localization of optically thin emission from superthermal electrons (50 endash 100 keV) was obtained by observation of emission upshifted from a thermal cyclotron harmonic. The localized measurements of the electron energy distribution and the superthermal density profile made by this diagnostic demonstrate its potential to study the spatial transport of energetic electrons on fast magnetohydrodynamic time scales or anomalous diffusion time scales. Oblique ECE can also be used to study electron distributions that may have a slight deviation from a Maxwellian by localizing the emission in energy space. (Abstract Truncated)

INvENTAIRE FLORISTIqUE ET EFFET DE LA DENSITÉ DE ...

African Journals Online (AJOL)

KyllingaerectaSchum. var. flabelliformis (Cyperaceae). +. +. +. 92. Kyllingapumila Michaux (Cyperaceae). +. +. +. 93. Lantana camara L. (verbenaceae). +. -. -. 94. Leptoderrisfasciculata(Benth.) Dunn. (Fabaceae). -. +. -. 95. Lindernia diffusa (L.) Wettst. (Scrophulariaceae). +. -. -. 96. Ludwigiaabyssinica A. Rich. (Onagraceae).

Electron microscopy of boron carbide before and after electron irradiation

International Nuclear Information System (INIS)

Stoto, T.; Zuppiroli, L.; Beauvy, M.; Athanassiadis, T.

1984-06-01

The microstructure of boron carbide has been studied by electron microscopy and related to the composition of the material. After electron irradiations in an usual transmission electron microscope and in a high voltage electron microscope at different temperatures and fluxes no change of these microstructures have been observed but a sputtering of the surface of the samples, which has been studied quantitatively [fr

Electron Cyclotron Resonances in Electron Cloud Dynamics

International Nuclear Information System (INIS)

Celata, Christine; Celata, C.M.; Furman, Miguel A.; Vay, J.-L.; Yu, Jennifer W.

2008-01-01

We report a previously unknown resonance for electron cloud dynamics. The 2D simulation code 'POSINST' was used to study the electron cloud buildup at different z positions in the International Linear Collider positron damping ring wiggler. An electron equilibrium density enhancement of up to a factor of 3 was found at magnetic field values for which the bunch frequency is an integral multiple of the electron cyclotron frequency. At low magnetic fields the effects of the resonance are prominent, but when B exceeds ∼(2 pi mec/(elb)), with lb = bunch length, effects of the resonance disappear. Thus short bunches and low B fields are required for observing the effect. The reason for the B field dependence, an explanation of the dynamics, and the results of the 2D simulations and of a single-particle tracking code used to elucidate details of the dynamics are discussed

Role of electron-electron interactions in the RKKY theory of magnetism

International Nuclear Information System (INIS)

Cooke, J.F.

1978-10-01

The theory of magnetism in heavy rare earth metals is based on the RKKY theory. In this formalism the indirect exchange interaction between the local 4f spins is mediated by the conduction electrons. When carried to second order in the 4f-conduction electron interaction, traditional perturbation theory leads to a Heisenberg-like interaction between the local spins which depends on the electronic energy bands and 4f-conduction electron exchange matrix elements. This derivation neglects the detailed behavior of electron-electron interaction within the conduction band, which is known to be important in metallic systems. By using an equation of motion method, an expression for the inelastic neutron scattering cross-section has been derived which includes, in an approximate way, this electron-electron interaction. The results of this calculation indicate that spin-wave peaks can be broadened and shifted if the spin-wave band lies near the conduction electron Stoner continuum. The origin of this effect is similar to that found in itinerant electron systems where the spin-wave band actually intersects the Stoner continuum, resulting in the disappearance of the spin-wave mode

Role of electron-electron interactions in the RKKY theory of magnetism

International Nuclear Information System (INIS)

Cooke, J.F.

1979-01-01

The theory of magnetism in heavy rare earth metals is based on the RKKY theory. In this formalism the indirect exchange interaction between the local 4f spins is mediated by the conduction electrons. When carried to second order in the 4f-conduction electron interaction, traditional pertubation theory leads to a Heisenberg-like interaction between the local spins which depends on the electronic energy bands and 4f-conduction electron exchange matrix elements. This derivation neglects the detailed behavior of electron-electron interaction within the conduction band, which is known to be important in metallic systems. By using an equation of motion method, an expression for the inelastic neutron scattering cross-section has been derived which includes, in an approximate way, this electron-electron interaction. The results of this calculation indicate that spin-wave peaks can be broadened and shifted if the spin-wave band lies near the conduction electron Stoner continuum. The origin of this effect is similar to that found in itinerant electron systems where the spin-wave band actually intersects the Stoner continuum, resulting in the disappearance of the spin-wave mode

Electron acoustic solitary waves in unmagnetized two electron population dense plasmas

International Nuclear Information System (INIS)

Mahmood, S.; Masood, W.

2008-01-01

The electron acoustic solitary waves are studied in unmagnetized two population electron quantum plasmas. The quantum hydrodynamic model is employed with the Sagdeev potential approach to describe the arbitrary amplitude electron acoustic waves in a two electron population dense Fermi plasma. It is found that hot electron density hump structures are formed in the subsonic region in such type of quantum plasmas. The wave amplitude as well as the width of the soliton are increased with the increase of percentage presence of cold (thinly populated) electrons in a multicomponent quantum plasma. It is found that an increase in quantum diffraction parameter broadens the nonlinear structure. Furthermore, the amplitude of the nonlinear electron acoustic wave is found to increase with the decrease in Mach number. The numerical results are also presented to understand the formation of solitons in two electron population Fermi plasmas.

Advances in imaging and electron physics the scanning transmission electron microscope

CERN Document Server

Hawkes, Peter W

2009-01-01

Advances in Imaging and Electron Physics merges two long-running serials--Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. This series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains.  This particular volume presents several timely articles on the scanning transmission electron microscope. Updated with contributions from leading international scholars and industry experts Discusses hot topic areas and presents current and future research trends Provides an invaluable reference and guide for physicists, engineers and mathematicians.

Attractive electron correlation in wide band gap semiconductors by electron-photon interaction

International Nuclear Information System (INIS)

Takeda, Hiroyuki; Yoshino, Katsumi

2004-01-01

We theoretically demonstrate attractive electron correlation in wide band gap semiconductors by electron-photon interaction. At low temperature, wavevectors of electromagnetic waves absorbed in wide band gap semiconductors cannot be neglected for wavevectors of electron waves; that is, electromagnetic waves affect the movements of electrons. In particular, attractive interaction occurs between two electrons when one electron changes from a valence band to a conduction band and the other electron changes from a conduction band to a valence band

Electronic Publishing or Electronic Information Handling?

Science.gov (United States)

Heck, A.

The current dramatic evolution in information technology is bringing major modifications in the way scientists communicate. The concept of 'electronic publishing' is too restrictive and has often different, sometimes conflicting, interpretations. It is thus giving way to the broader notion of 'electronic information handling' encompassing the diverse types of information, the different media, as well as the various communication methodologies and technologies. New problems and challenges result also from this new information culture, especially on legal, ethical, and educational grounds. The procedures for validating 'published material' and for evaluating scientific activities will have to be adjusted too. 'Fluid' information is becoming a common concept. Electronic publishing cannot be conceived without link to knowledge bases nor without intelligent information retrieval tools.

Theoretical study of the interplay of electron-electron interaction and disorder

International Nuclear Information System (INIS)

Brezini, A.; Behilil, S.

1988-10-01

A disordered Hubbard model with diagonal disorder is used to investigate the electron localization effects associated with both disorder and electron-electron interaction. Extensive results are reported on the ground state properties and compared to other theories. Two regimes have been found: when the electron-electron interaction u is greater than the disorder parameter w and when u < w. (author). 18 refs, 4 figs

Defining Electron Bifurcation in the Electron-Transferring Flavoprotein Family.

Science.gov (United States)

Garcia Costas, Amaya M; Poudel, Saroj; Miller, Anne-Frances; Schut, Gerrit J; Ledbetter, Rhesa N; Fixen, Kathryn R; Seefeldt, Lance C; Adams, Michael W W; Harwood, Caroline S; Boyd, Eric S; Peters, John W

2017-11-01

Electron bifurcation is the coupling of exergonic and endergonic redox reactions to simultaneously generate (or utilize) low- and high-potential electrons. It is the third recognized form of energy conservation in biology and was recently described for select electron-transferring flavoproteins (Etfs). Etfs are flavin-containing heterodimers best known for donating electrons derived from fatty acid and amino acid oxidation to an electron transfer respiratory chain via Etf-quinone oxidoreductase. Canonical examples contain a flavin adenine dinucleotide (FAD) that is involved in electron transfer, as well as a non-redox-active AMP. However, Etfs demonstrated to bifurcate electrons contain a second FAD in place of the AMP. To expand our understanding of the functional variety and metabolic significance of Etfs and to identify amino acid sequence motifs that potentially enable electron bifurcation, we compiled 1,314 Etf protein sequences from genome sequence databases and subjected them to informatic and structural analyses. Etfs were identified in diverse archaea and bacteria, and they clustered into five distinct well-supported groups, based on their amino acid sequences. Gene neighborhood analyses indicated that these Etf group designations largely correspond to putative differences in functionality. Etfs with the demonstrated ability to bifurcate were found to form one group, suggesting that distinct conserved amino acid sequence motifs enable this capability. Indeed, structural modeling and sequence alignments revealed that identifying residues occur in the NADH- and FAD-binding regions of bifurcating Etfs. Collectively, a new classification scheme for Etf proteins that delineates putative bifurcating versus nonbifurcating members is presented and suggests that Etf-mediated bifurcation is associated with surprisingly diverse enzymes. IMPORTANCE Electron bifurcation has recently been recognized as an electron transfer mechanism used by microorganisms to maximize

Effects of electron-electron interactions on the electron distribution function of a plasma in the presence of an external electric field

International Nuclear Information System (INIS)

Molinari, V.G.; Pizzio, F.; Spiga, G.

1979-01-01

The electron distribution function, the electron temperature and some transport parameters (electrical conductivity and energy flow coefficient) are obtained starting from the nonlinear Boltzmann equation for a plasma under the action of an external electric field. The Fokker-Planck approximation is used for electron-electron and electron-ion interactions. The effects of electron-electron collisions are studied for different values of collision frequencies and electric field. (author)

Electron-excited molecule interactions

International Nuclear Information System (INIS)

Christophorou, L.G.; Tennessee Univ., Knoxville, TN

1991-01-01

In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10 6 to 10 7 times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs

Seeing with electrons

International Nuclear Information System (INIS)

Nellist, P.

2006-01-01

Commercially available lens correctors are extending the reach of electron microscopes to unprecedented atomic scales, as Peter Nellist describes. The electron microscope was invented in 1933 and is based on the principle that electrons have a wavelength that is inversely proportional to their momentum. There are two basic types: transmission electron microscopes and scanning electron microscopes, plus a hybrid of the two. The lenses in an electron microscope are provided by electromagnetic fields, but they suffer from spherical aberration. The addition of octupole and quadrupole corrector fields has improved the resolution of the electron microscope to better than 0.1 nm in the last decade. The next step is to correct for chromatic aberration, after which the resolution of the microscope will probably be limited by the size of the atom itself. (U.K.)

Introduction to electronics

CERN Multimedia

CERN. Geneva

2005-01-01

Electronics in HEP experiments: specificities and evolution The Art of Electronics: is there something beyond Ohm's law? Basic building blocks of Analog electronics: quickly understanding a schematic Charge preamps, current preamps and future preamps, shaping and the rest Electronics noise: fundamental and practical Evolution of technology: ASICs, FPGAs...

Multiple electron generation in a sea of electronic states

Science.gov (United States)

Witzel, Wayne; Shabaev, Andrew; Efros, Alexander; Hellberg, Carl; Verne, Jacobs

2009-03-01

In traditional bulk semiconductor photovoltaics (PVs), each photon may excite a single electron-hole, wasting excess energy beyond the band-gap as heat. In nanocrystals, multiple excitons can be generated from a single photon, enhancing the PV current. Multiple electron generation (MEG) may result from Coulombic interactions of the confined electrons. Previous investigations have been based on incomplete or over-simplified electronic-state representations. We present results of quantum simulations that include hundreds of thousands of configuration states and show how the complex dynamics, even in a closed electronic system, yields a saturated MEG effect on a femtosecond timescale. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Electron collision cross sections and electron swarm parameters for gas molecules

International Nuclear Information System (INIS)

Hayashi, Makoto

1986-01-01

Elastic and inelastic electron collision cross sections for molecules which interest in radiation research have been determined from available electron beam and electron swarm data by utilizing the Boltzmann equation and Monte Carlo simulation method. Electron drift velocity data which interest in radiation Pysics have been discussed and some calculated results of electron drift velocity data for CF 4 and CF 4 -inert gases mixtures will be presented. (author)

Vigna subterranea (L.) Verdc. Fabaceae

African Journals Online (AJOL)

PR BOKO

Désinfection en surface des graines et préparation de l'explant. Les graines ont subi un trempage rapide (1min) dans l'éthanol 70 % (v/v), suivi de l'immersion pendant 30 min dans l'hypochlorite de calcium 7 % (m/v). Elles ont ensuite été abondamment rincées dans de l'eau distillée stérile. Après 48 heures d'imbibition à ...

and Rooibos (Aspalathus linearis Fabaceae)

African Journals Online (AJOL)

0.05) increased the activity of pyruvate kinase in the liver when compared with the diabetic control group. Conclusion: ... include single ring phenolic acids and monomeric flavonoids ... antioxidant properties. The present ..... such as ALT indicates the concentration of .... Joubert E, Gelderblom WC, Louw A, de Beer D. South.

IN Hedysarum coronarium L. (FABACEAE)

African Journals Online (AJOL)

Figure 1 : A picture showing an erect plant of H. coronarium at flowering stage. This phenotype is ... LOS : mean height of principal stem at the end of plant development (cm) ;. LHS : mean length of ..... classification factor. Mahalanobis distan-.

Environ: E00498 [KEGG MEDICUS

Lifescience Database Archive (English)

Full Text Available E00498 Spatholobus suberectus, Mucuna birdwoodiana stem Crude drug ... Spatholobus su...berectus [TAX:455371], Mucuna birdwoodiana, Mucuna [TAX:40336] ... Fabaceae (pea family) Spatholobus suberectus, Mucuna birdwoodiana stem (dried) ...

Caracterización y variación espacio-temporal del néctar en anarthrophyllum desideratum (Fabaceae: Influencia del clima y los polinizadores

Directory of Open Access Journals (Sweden)

Valeria Paiaro

2012-12-01

Full Text Available En este trabajo se caracterizó el volumen, la concentración y la composición de azúcares del néctar floral en Anarthrophyllum desideratum (DC Benth., un arbusto endémico de la estepa Patagónica polinizado por aves Passeriformes, y se evaluó su variación espacio-temporal. Se analizaron las diferencias entre áreas ecológicas, poblaciones, plantas y años, y las relaciones entre rasgos, la temperatura, precipitación y tasa de visitas de las poblaciones. El néctar mostró un volumen promedio de 8,1 µl, una concentración de 28% y estuvo dominado por hexosas, como en otras especies ornitófilas. Los atributos del néctar estuvieron correlacionados a nivel poblacional, y las diferencias entre poblaciones explicaron la mayor parte de su variabilidad espacial. El volumen y la concentración variaron entre años, mientras que la composición de azúcares se mantuvo constante. La proporción de glucosa disminuyó con el aumento de la temperatura, pero el resto de los caracteres no se asoció con las variaciones climáticas de la región. El volumen de néctar disminuyó a medida que aumentó la tasa de visitas de las poblaciones. Los resultados sugieren la existencia de una importante variación espacio-temporal del néctar en A. desideratum que no respondería a gradientes ambientales simples sino a un escenario complejo con múltiples factores.Characterization and spatio-temporal variation of nectar in Anarthrophyllum desideratum (Fabaceae: Influence of climate and pollinators. In this study we characterized the volume, concentration and sugar composition of floral nectar in Anarthrophyllum desideratum (DC Benth., an endemic shrub from the Patagonian steppe pollinated by Passerine birds, and we evaluated it spatio-temporal variation. We analyzed the differences among ecological areas, populations, plants and years, and the relationships between traits, the temperature, rainfall and visitation rate of populations. Nectar showed an average

Electronic payment systems

OpenAIRE

Mláka, Michal

2010-01-01

This bachelor thesis analysis issue of electronic payment systems. It discusses their use for payments on the internet and sending funds via e-mail. The first part is devoted to the theoretical definition and legislation of the issuance of electronic money and activities of electronic money institutions. The main part of the work clearly focuses on the use of e-wallets, which is an integral part of electronic payment systems. E-wallet of electronic payment system Moneybookers is considered as...

Wigner-like crystallization of Anderson-localized electron systems with low electron densities

CERN Document Server

Slutskin, A A; Pepper, M

2002-01-01

We consider an electron system under conditions of strong Anderson localization, taking into account interelectron long-range Coulomb repulsion. We establish that at sufficiently low electron densities and sufficiently low temperatures the Coulomb electron interaction brings about ordering of the Anderson-localized electrons into a structure that is close to an ideal (Wigner) crystal lattice, provided the dimension of the system is > 1. This Anderson-Wigner glass (AWG) is a new macroscopic electron state that, on the one hand, is beyond the conventional Fermi glass concept, and on the other hand, qualitatively differs from the known 'plain' Wigner glass (inherent in self-localized electron systems) in that the random slight electron displacements from the ideal crystal sites essentially depend on the electron density. With increasing electron density the AWG is found to turn into the plain Wigner glass or Fermi glass, depending on the width of the random spread of the electron levels. It is shown that the res...

Excess electrons in methanol clusters: Beyond the one-electron picture

Science.gov (United States)

Pohl, Gábor; Mones, Letif; Turi, László

2016-10-01

We performed a series of comparative quantum chemical calculations on various size negatively charged methanol clusters, ("separators=" CH 3 OH ) n - . The clusters are examined in their optimized geometries (n = 2-4), and in geometries taken from mixed quantum-classical molecular dynamics simulations at finite temperature (n = 2-128). These latter structures model potential electron binding sites in methanol clusters and in bulk methanol. In particular, we compute the vertical detachment energy (VDE) of an excess electron from increasing size methanol cluster anions using quantum chemical computations at various levels of theory including a one-electron pseudopotential model, several density functional theory (DFT) based methods, MP2 and coupled-cluster CCSD(T) calculations. The results suggest that at least four methanol molecules are needed to bind an excess electron on a hydrogen bonded methanol chain in a dipole bound state. Larger methanol clusters are able to form stronger interactions with an excess electron. The two simulated excess electron binding motifs in methanol clusters, interior and surface states, correlate well with distinct, experimentally found VDE tendencies with size. Interior states in a solvent cavity are stabilized significantly stronger than electron states on cluster surfaces. Although we find that all the examined quantum chemistry methods more or less overestimate the strength of the experimental excess electron stabilization, MP2, LC-BLYP, and BHandHLYP methods with diffuse basis sets provide a significantly better estimate of the VDE than traditional DFT methods (BLYP, B3LYP, X3LYP, PBE0). A comparison to the better performing many electron methods indicates that the examined one-electron pseudopotential can be reasonably used in simulations for systems of larger size.

Electron dose rate and photon contamination in electron arc therapy

International Nuclear Information System (INIS)

Pla, M.; Podgorsak, E.B.; Pla, C.

1989-01-01

The electron dose rate at the depth of dose maximum dmax and the photon contamination are discussed as a function of several parameters of the rotational electron beam. A pseudoarc technique with an angular increment of 10 degrees and a constant number of monitor units per each stationary electron field was used in our experiments. The electron dose rate is defined as the electron dose at a given point in phantom divided by the number of monitor units given for any one stationary electron beam. For a given depth of isocenter di the electron dose rates at dmax are linearly dependent on the nominal field width w, while for a given w the dose rates are inversely proportional to di. The dose rates for rotational electron beams with different di are related through the inverse square law provided that the two beams have (di,w) combinations which give the same characteristic angle beta. The photon dose at the isocenter depends on the arc angle alpha, field width w, and isocenter depth di. For constant w and di the photon dose at isocenter is proportional to alpha, for constant alpha and w it is proportional to di, and for constant alpha and di it is inversely proportional to w. The w and di dependence implies that for the same alpha the photon dose at the isocenter is inversely proportional to the electron dose rate at dmax

Power Electronics

DEFF Research Database (Denmark)

Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

2008-01-01

is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most...... emerging renewable energy sources, wind energy, which by means of power electronics are changing from being a minor energy source to be acting as an important power source in the energy system. Power electronics is the enabling technology and the presentation will cover the development in wind turbine...... technology from kW to MW, discuss which power electronic solutions are most feasible and used today....

Electron Emission from Ultra-Large Area MOS Electron Emitters

DEFF Research Database (Denmark)

Thomsen, Lasse Bjørchmar; Nielsen, Gunver; Vendelbo, Søren Bastholm

2009-01-01

Ultralarge metal-oxide-semiconductor (MOS) devices with an active oxide area of 1 cm2 have been fabricated for use as electron emitters. The MOS structures consist of a Si substrate, a SiO2 tunnel barrier (~5 nm), a Ti wetting layer (3–10 Å), and a Au top layer (5–60 nm). Electron emission from...... layer is varied from 3 to 10 Å which changes the emission efficiency by more than one order of magnitude. The apparent mean free path of ~5 eV electrons in Au is found to be 52 Å. Deposition of Cs on the Au film increased the electron emission efficiency to 4.3% at 4 V by lowering the work function....... Electron emission under high pressures (up to 2 bars) of Ar was observed. ©2009 American Vacuum Society...

Comparative analysis of the terms "electronic commerce" and "electronic business"

OpenAIRE

Kavaliauskienė, Virginija; Šarapovas, Tadas

2002-01-01

Establishing the terms that clearly and consistently describe growing and dynamic networked economy is a critical first step toward further analysis and evaluation of electronic commerce and electronic business processes. Electronic commerce is making an impact on the ways that purchasing activities are being conducted. Much of the early literature on this subject was very speculative. However, the growth of e-commerce has enabled more observations to be made of the use of electronic business...

Electron-electron interaction and transfer ionization in fast ion-atom collisions

International Nuclear Information System (INIS)

Voitkiv, A B

2008-01-01

Recently it was pointed out that electron capture occurring in fast ion-atom collisions can proceed via a mechanism which earlier was not considered. In the present paper we study this mechanism in more detail. Similarly as in radiative capture, where the electron transfer occurs due to the interaction with the radiation field and proceeds via emission of a photon, within this mechanism the electron capture is caused by the interaction with another atomic electron leading mainly to the emission of the latter. In contrast to the electron-electron Thomas capture, this electron-electron (E-E) mechanism is basically a first-order one having similarities to the kinematic and radiative capture channels. It also possesses important differences with the latter two. Leading to transfer ionization, this first-order capture mechanism results in the electron emission mainly in the direction opposite to the motion of the projectile ion. The same, although less pronounced, feature is also characteristic for the momenta of the target recoil ions produced via this mechanism. It is also shown that the action of the E-E mechanism is clearly seen in recent experimental data on the transfer ionization in fast proton-helium collisions.

Determination of electron temperature and electron density in ...

African Journals Online (AJOL)

It is seen that the electron temperature increases from 5.8 × 102 oK to 7.83 × 104 oK as the pd is reduced from 130mm Hg × mm to 60 mm Hg × mm for argon. The electron densities increases from 2.8 × 1011/cm3 to 3.2 × 1011 /cm3 for the same variation of pds. For air the electron temperature increases from 3.6 × 104 oK to ...

Optimising electron microscopy experiment through electron optics simulation

Energy Technology Data Exchange (ETDEWEB)

Kubo, Y. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France); Hitachi High-Technologies Corporation, 882, Ichige, Hitachinaka, Ibaraki 312-8504 (Japan); Gatel, C.; Snoeck, E. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France); Houdellier, F., E-mail: florent.houdellier@cemes.fr [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France)

2017-04-15

We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e. the field emission (FE) cathode, the extraction optic and acceleration stages of a 300 kV cold field emission gun, the illumination lenses, the objective lens, the intermediate and projection lenses. Full trajectories can be computed using magnetically saturated or non-saturated round lenses, magnetic deflectors and even non-cylindrical symmetry elements like electrostatic biprism. This multi-scale model gathers nanometer size components (FE tip) with parts of meter length (illumination and projection systems). We demonstrate that non-trivial TEM experiments requiring specific and complex optical configurations can be simulated and optimized prior to any experiment using such model. We show that all the currents set in all optical elements of the simulated column can be implemented in the real column (I2TEM in CEMES) and used as starting alignment for the requested experiment. We argue that the combination of such complete electron trajectory simulations in the whole TEM column with automatic optimization of the microscope parameters for optimal experimental data (images, diffraction, spectra) allows drastically simplifying the implementation of complex experiments in TEM and will facilitate the development of advanced use of the electron microscope in the near future. - Highlights: • Using dedicated electron optics software, we calculate full electrons trajectories inside a modern transmission electron microscope. • We have determined how to deal with multi-scale electron optics elements like high voltage cold field emission source. • W • e have succeed to model both weak and strong magnetic lenses whether in saturated or unsaturated conditions as well as electrostatic biprism and magnetic deflectors. • We have applied this model

Optimising electron microscopy experiment through electron optics simulation

International Nuclear Information System (INIS)

Kubo, Y.; Gatel, C.; Snoeck, E.; Houdellier, F.

2017-01-01

We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e. the field emission (FE) cathode, the extraction optic and acceleration stages of a 300 kV cold field emission gun, the illumination lenses, the objective lens, the intermediate and projection lenses. Full trajectories can be computed using magnetically saturated or non-saturated round lenses, magnetic deflectors and even non-cylindrical symmetry elements like electrostatic biprism. This multi-scale model gathers nanometer size components (FE tip) with parts of meter length (illumination and projection systems). We demonstrate that non-trivial TEM experiments requiring specific and complex optical configurations can be simulated and optimized prior to any experiment using such model. We show that all the currents set in all optical elements of the simulated column can be implemented in the real column (I2TEM in CEMES) and used as starting alignment for the requested experiment. We argue that the combination of such complete electron trajectory simulations in the whole TEM column with automatic optimization of the microscope parameters for optimal experimental data (images, diffraction, spectra) allows drastically simplifying the implementation of complex experiments in TEM and will facilitate the development of advanced use of the electron microscope in the near future. - Highlights: • Using dedicated electron optics software, we calculate full electrons trajectories inside a modern transmission electron microscope. • We have determined how to deal with multi-scale electron optics elements like high voltage cold field emission source. • W • e have succeed to model both weak and strong magnetic lenses whether in saturated or unsaturated conditions as well as electrostatic biprism and magnetic deflectors. • We have applied this model

Lead-Free Electronics: Impact for Space Electronics

Science.gov (United States)

Sampson, Michael J.

2010-01-01

Pb is used as a constituent in solder alloys used to connect and attach electronic parts to printed wiring boards (PWBs). Similar Pbbearing alloys are electroplated or hot dipped onto the terminations of electronic parts to protect the terminations and make them solderable. Changing to Pb-free solders and termination finishes has introduced significant technical challenges into the supply chain. Tin/lead (Sn/Pb) alloys have been the solders of choice for electronics for more than 50 years. Pb-free solder alloys are available but there is not a plug-in replacement for 60/40 or 63/37 (Sn/Pb) alloys, which have been the industry workhorses.

Observation of electron plasma waves in plasma of two-temperature electrons

International Nuclear Information System (INIS)

Ikezawa, Shunjiro; Nakamura, Yoshiharu.

1981-01-01

Propagation of electron plasma waves in a large and unmagnetized plasma containing two Maxwellian distributions of electrons is studied experimentally. Two kinds of plasma sources which supply electrons of different temperature are used. The temperature ratio is about 3 and the density ratio of hot to cool electrons is varied from 0 to 0.5. A small contamination of hot electrons enhances the Landau damping of the principal mode known as the Bohm-Gross mode. When the density of hot electrons is larger than about 0.2, two modes are observed. The results agree with theoretical dispersion relations when excitation efficiencies of the modes are considered. (author)

Electron energy and electron trajectories in an inverse free-electron laser accelerator based on a novel electrostatic wiggler

Science.gov (United States)

Nikrah, M.; Jafari, S.

2016-06-01

We expand here a theory of a high-gradient laser-excited electron accelerator based on an inverse free-electron laser (inverse-FEL), but with innovations in the structure and design. The electrostatic wiggler used in our scheme, namely termed the Paul wiggler, is generated by segmented cylindrical electrodes with applied oscillatory voltages {{V}\\text{osc}}(t) over {{90}\\circ} segments. The inverse-FEL interaction can be described by the equations that govern the electron motion in the combined fields of both the laser pulse and Paul wiggler field. A numerical study of electron energy and electron trajectories has been made using the fourth-order Runge-Kutta method. The results indicate that the electron attains a considerable energy at short distances in this device. It is found that if the electron has got sufficient suitable wiggler amplitude intensities, it can not only gain higher energy in longer distances, but also can retain it even after the passing of the laser pulse. In addition, the results reveal that the electron energy gains different peaks for different initial axial velocities, so that a suitable small initial axial velocity of e-beam produces substantially high energy gain. With regard to the transverse confinement of the electron beam in a Paul wiggler, there is no applied axial guide magnetic field in this device.

Plasmaspheric electron content

International Nuclear Information System (INIS)

Hartmann, G.K.

1978-01-01

Measurements of the plasmaspheric electron content are reviewed with particular reference to the ATS-6 radio beacon experiment. From the review, it appears likely that measurement of the plasmaspheric electron content is the only one capable of monitoring electron fluxes continuously between L 1 and L 2. Some recent important results deduced from plasmaspheric electron content measurements are discussed

A 20 keV electron gun system for the electron irradiation experiments

International Nuclear Information System (INIS)

Mahapatra, S.K.; Dhole, S.D.; Bhoraskar, V.N.

2005-01-01

An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 μA. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure ∼10 -7 mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours

A 20 keV electron gun system for the electron irradiation experiments

Energy Technology Data Exchange (ETDEWEB)

Mahapatra, S.K. [Department of Physics, University of Pune, Pune 411007 (India); Dhole, S.D. [Department of Physics, University of Pune, Pune 411007 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India)]. E-mail: vnb@physics.unipune.ernet.in

2005-01-01

An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 {mu}A. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure {approx}10{sup -7} mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours.

Effect of electron beam on the properties of electron-acoustic rogue waves

Science.gov (United States)

El-Shewy, E. K.; Elwakil, S. A.; El-Hanbaly, A. M.; Kassem, A. I.

2015-04-01

The properties of nonlinear electron-acoustic rogue waves have been investigated in an unmagnetized collisionless four-component plasma system consisting of a cold electron fluid, Maxwellian hot electrons, an electron beam and stationary ions. It is found that the basic set of fluid equations is reduced to a nonlinear Schrodinger equation. The dependence of rogue wave profiles and the associated electric field on the carrier wave number, normalized density of hot electron and electron beam, relative cold electron temperature and relative beam temperature are discussed. The results of the present investigation may be applicable in auroral zone plasma.

Electron cooling and recombination experiments with an adiabatically expanded electron beam

International Nuclear Information System (INIS)

Pastuszka, S.; Heidelberg Univ.; Schramm, U.; Heidelberg Univ.; Grieser, M.; Heidelberg Univ.; Broude, C.; Heidelberg Univ.; Grimm, R.; Heidelberg Univ.; Habs, D.; Heidelberg Univ.; Kenntner, J.; Heidelberg Univ.; Miesner, H.J.; Heidelberg Univ.; Schuessler, T.; Heidelberg Univ.; Schwalm, D.; Heidelberg Univ.; Wolf, A.; Heidelberg Univ.

1996-01-01

Magnetically guided electron beams with transverse temperatures reduced with respect to the cathode temperature by a factor of more than 7 were realized in the electron cooling device of the heavy-ion storage ring TSR and the effect of the reduced transverse temperature in recombination and electron cooling experiments was studied. Measured dielectronic recombination resonances at low relative energy and spectra of laser-stimulated recombination indicate that transverse electron temperatures of about 17 meV have been obtained at cathode temperatures of about 110 meV. The temperature dependence of the spontaneous electron-ion recombination rate during electron cooling was investigated and found to follow the inverse square-root law expected from the theory of radiative recombination, although the measured absolute rates are higher than predicted. A new method based on analyzing the intensity of the fluorescence light emitted during simultaneous laser and electron cooling is used to measure the longitudinal electron cooling force in a range of relative velocities extending over two orders of magnitude (10 5 -10 7 cm/s). The results confirm the occurrence of 'magnetized electron cooling' also at the reduced transverse temperature and show that, compared to earlier measurements at the high transverse temperature, the cooling force increases by about a factor of 2; a considerably larger increase by a factor of ∼5 would be expected if 'magnetized electron cooling' would not exist. (orig.)

Electronic structure of elements and compounds and electronic phases of solids

International Nuclear Information System (INIS)

Nadykto, B.A.

2000-01-01

The paper reviews technique and computed energies for various electronic states of many-electron multiply charged ions, molecular ions, and electronic phases of solids. The model used allows computation of the state energy for free many-electron multiply charged ions with relative accuracy ∼10 -4 suitable for analysis of spectroscopy data

Three-dimensional nanofabrication by electron-beam-induced deposition using 200-keV electrons in scanning transmission electron microscope

International Nuclear Information System (INIS)

Liu, Z.Q.; Mitsuishi, K.; Furuya, K.

2005-01-01

Attempts were made to fabricate three-dimensional nanostructures on and out of a substrate by electron-beam-induced deposition in a 200-kV scanning transmission electron microscope. Structures with parallel wires over the substrate surface were difficult to fabricate due to the direct deposition of wires on both top and bottom surfaces of the substrate. Within the penetration depth of the incident electron beam, nanotweezers were fabricated by moving the electron beam beyond different substrate layers. Combining the deposition of self-supporting wires and self-standing tips, complicated three-dimensional doll-like, flag-like, and gate-like nanostructures that extend out of the substrate were successfully fabricated with one-step or multi-step scans of the electron beam. Effects of coarsening, nucleation, and distortion during electron-beam-induced deposition are discussed. (orig.)

Secondary electron emission yield in the limit of low electron energy

CERN Document Server

Andronov, A.N.; Kaganovich, I.D.; Startsev, E.A.; Raitses, Y.; Demidov, V.I.

2013-04-22

Secondary electron emission (SEE) from solids plays an important role in many areas of science and technology.1 In recent years, there has been renewed interest in the experimental and theoretical studies of SEE. A recent study proposed that the reflectivity of very low energy electrons from solid surface approaches unity in the limit of zero electron energy2,3,4, If this was indeed the case, this effect would have profound implications on the formation of electron clouds in particle accelerators,2-4 plasma measurements with electrostatic Langmuir probes, and operation of Hall plasma thrusters for spacecraft propulsion5,6. It appears that, the proposed high electron reflectivity at low electron energies contradicts to numerous previous experimental studies of the secondary electron emission7. The goal of this note is to discuss possible causes of these contradictions.

Electron spectroscopy

International Nuclear Information System (INIS)

Hegde, M.S.

1979-01-01

An introduction to the various techniques in electron spectroscopy is presented. These techniques include: (1) UV Photoelectron spectroscopy, (2) X-ray Photoelectron spectroscopy, (3) Auger electron spectroscopy, (4) Electron energy loss spectroscopy, (5) Penning ionization spectroscopy and (6) Ion neutralization spectroscopy. The radiations used in each technique, the basis of the technique and the special information obtained in structure determination in atoms and molecules by each technique are summarised. (A.K.)

Dieta de murciélagos nectarívoros del Parque Nacional Cerros de Amotape, Tumbes

Directory of Open Access Journals (Sweden)

Edith Arias

2011-07-01

Full Text Available En el Perú se reporta la presencia de 18 especies de murciélagos nectarívoros, sin embargo se cuenta con poca información sobre la dieta de estas especies. En este estudio se reporta por primera vez la dieta de los nectarívoros Glossophaga soricina, Lonchophylla hesperia y Anoura geoffroyi en el bosque seco ecuatorial y del bosque tropical del Pacífico del Parque Nacional Cerros de Amotape, Tumbes. Analizamos 21 contenidos gastrointestinales e identificamos ocho morfotipos de polen pertenecientes a las familias Bombacaceae, Cactaceae, Fabaceae, Solanaceae, Rubiaceae, Myrtaceae, Malvaceae y Rosaceae. Encontramos evidencia del síndrome de quiropterofilia en Bombacaceae, Cactaceae, Fabaceae, Solanaceae y Rubiaceae. Observamos que A. geoffroyi consume polen de Ceiba trichistandra, Solanaceae y Rubiacea; G. soricina consume de Abutilon reflexum, Armathocereus cartwrightianus, C. trichistandra y Rubiaceae; y L. hesperia de A. cartwrightianus, Eriobotrya japonica, Fabaceae y Psidium sp.; sugiriendo una dieta generalista en estas especies. Los murciélagos G. soricina y A. geoffroyi comparten el consumo del ceibo C. trichistandra y de la Rubiaceae, mientras que G. soricina comparte con L. hesperia el consumo del cactus A. cartwrightianus. Los otros morfotipos de polen no fueron compartidos entre murciélagos. Se encuentra además que el ceibo C. trichistandra fue la especie más consumida, especialmente por G. soricina.

Perpendicular electron cyclotron emission from hot electrons in TMX-U

International Nuclear Information System (INIS)

James, R.A.; Ellis, R.F.; Lasnier, C.J.; Casper, T.A.; Celata, C.M.

1984-01-01

Perpendicular electron cyclotron emission (PECE) from the electron cyclotron resonant heating of hot electrons in TMX-U is measured at 30 to 40 and 50 to 75 GHz. This emission is optically thin and is measured at the midplane, f/sub ce/ approx. = 14 GHz, in either end cell. In the west end cell, the emission can be measured at different axial positions thus yielding the temporal history of the hot electron axial profile. These profiles are in excellent agreement with the axial diamagnetic signals. In addition, the PECE signal level correlates well with the diamagnetic signal over a wide range of hot electron densities. Preliminary results from theoretical modeling and comparisons with other diagnostics are also presented

A ferroelectric electron gun in a free-electron maser experiment

International Nuclear Information System (INIS)

Einat, M.; Jerby, E.; Rosenman, G.

2002-01-01

An electron-gun based on a ferroelectric cathode is studied in a free-electron maser (FEM) experiment. In this gun, the electrons are separated from the cathode surface plasma, and are accelerated in two stages. The electron energy-spread is reduced sufficiently for an FEM operation in the microwave regime. A 14 keV, 1-2 A e-beam is obtained in a 0.1-2.1 μs pulse width. The pulse repetition frequency attains 3.1 MHz in ∼50% duty-cycle. This gun is implemented in an FEM oscillator experiment operating around 3 GHz. The paper presents experimental results and discusses the applicability of ferroelectric guns in free-electron laser devices

A ferroelectric electron gun in a free-electron maser experiment

CERN Document Server

Einat, M; Rosenman, G

2002-01-01

An electron-gun based on a ferroelectric cathode is studied in a free-electron maser (FEM) experiment. In this gun, the electrons are separated from the cathode surface plasma, and are accelerated in two stages. The electron energy-spread is reduced sufficiently for an FEM operation in the microwave regime. A 14 keV, 1-2 A e-beam is obtained in a 0.1-2.1 mu s pulse width. The pulse repetition frequency attains 3.1 MHz in approx 50% duty-cycle. This gun is implemented in an FEM oscillator experiment operating around 3 GHz. The paper presents experimental results and discusses the applicability of ferroelectric guns in free-electron laser devices.

Paper electronics.

Science.gov (United States)

Tobjörk, Daniel; Österbacka, Ronald

2011-05-03

Paper is ubiquitous in everyday life and a truly low-cost substrate. The use of paper substrates could be extended even further, if electronic applications would be applied next to or below the printed graphics. However, applying electronics on paper is challenging. The paper surface is not only very rough compared to plastics, but is also porous. While this is detrimental for most electronic devices manufactured directly onto paper substrates, there are also approaches that are compatible with the rough and absorptive paper surface. In this review, recent advances and possibilities of these approaches are evaluated and the limitations of paper electronics are discussed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Destabilization of the electron Bernstein modes by runaway electrons

International Nuclear Information System (INIS)

Hitchcock, D.A.; Mahajan, S.M.

1982-01-01

It is shown that the electromagnetic finite k/sub parallel/ electron Bernstein mode can be destabilized by the runaway electron distribution which results from the quasilinear action of the magnetized plasma oscillation. This mechanism is shown to yield growth rates of the order of 10 8 sec -1 and is suggested as a mechanism for the enchanced cyclotron harmonic emission in the presence of runaway electrons

Surface-electronic-state effects in electron emission from the Be(0001) surface

International Nuclear Information System (INIS)

Archubi, C. D.; Gravielle, M. S.; Silkin, V. M.

2011-01-01

We study the electron emission produced by swift protons impinging grazingly on a Be(0001) surface. The process is described within a collisional formalism using the band-structure-based (BSB) approximation to represent the electron-surface interaction. The BSB model provides an accurate description of the electronic band structure of the solid and the surface-induced potential. Within this approach we derive both bulk and surface electronic states, with these latter characterized by a strong localization at the crystal surface. We found that such surface electronic states play an important role in double-differential energy- and angle-resolved electron emission probabilities, producing noticeable structures in the electron emission spectra.

Surface-electronic-state effects in electron emission from the Be(0001) surface

Energy Technology Data Exchange (ETDEWEB)

Archubi, C. D. [Instituto de Astronomia y Fisica del Espacio, casilla de correo 67, sucursal 28, C1428EGA, Buenos Aires (Argentina); Gravielle, M. S. [Instituto de Astronomia y Fisica del Espacio, casilla de correo 67, sucursal 28, C1428EGA, Buenos Aires (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina); Silkin, V. M. [Donostia International Physics Center, E-20018 San Sebastian (Spain); Departamento de Fisica de Materiales, Facultad de Ciencias Quimicas, Universidad del Pais Vasco, Apartado 1072, E-20080 San Sebastian (Spain); IKERBASQUE, Basque Foundation for Science, E-48011 Bilbao (Spain)

2011-07-15

We study the electron emission produced by swift protons impinging grazingly on a Be(0001) surface. The process is described within a collisional formalism using the band-structure-based (BSB) approximation to represent the electron-surface interaction. The BSB model provides an accurate description of the electronic band structure of the solid and the surface-induced potential. Within this approach we derive both bulk and surface electronic states, with these latter characterized by a strong localization at the crystal surface. We found that such surface electronic states play an important role in double-differential energy- and angle-resolved electron emission probabilities, producing noticeable structures in the electron emission spectra.

Simulation of the electron acoustic instability for a finite-size electron beam system

International Nuclear Information System (INIS)

Lin, C.S.; Winske, D.

1987-01-01

Satellite observations at midlatitudes (≅20,000 km) near the earth's dayside polar cusp boundary layer indicate that the upward electron beams have a narrow latitudinal width up to 0.1 0 . In the cusp boundary layer where the electron population consists of a finite-size electron beam in a background of uniform cold and hot electrons, the electron acoustic mode is unstable inside the electron beam but damped outside the electron beam. Simulations of the electron acoustic instability for a finite-size beam system are carried out with a particle-in-cell code to investigate the heating phenomena associated with the instability and the width of the heating region. The simulations show that the finite-size electron beam radiates electrostatic electron acoustic waves. The decay length of the electron acoustic waves outside the beam in the simulation agrees with the spatial decay length derived from the linear dispersion equation

Arbitrary amplitude slow electron-acoustic solitons in three-electron temperature space plasmas

International Nuclear Information System (INIS)

Mbuli, L. N.; Maharaj, S. K.; Bharuthram, R.; Singh, S. V.; Lakhina, G. S.

2015-01-01

We examine the characteristics of large amplitude slow electron-acoustic solitons supported in a four-component unmagnetised plasma composed of cool, warm, hot electrons, and cool ions. The inertia and pressure for all the species in this plasma system are retained by assuming that they are adiabatic fluids. Our findings reveal that both positive and negative potential slow electron-acoustic solitons are supported in the four-component plasma system. The polarity switch of the slow electron-acoustic solitons is determined by the number densities of the cool and warm electrons. Negative potential solitons, which are limited by the cool and warm electron number densities becoming unreal and the occurrence of negative potential double layers, are found for low values of the cool electron density, while the positive potential solitons occurring for large values of the cool electron density are only limited by positive potential double layers. Both the lower and upper Mach numbers for the slow electron-acoustic solitons are computed and discussed

Electron cloud dynamics in the Cornell Electron Storage Ring Test Accelerator wiggler

Directory of Open Access Journals (Sweden)

C. M. Celata

2011-04-01

Full Text Available The interference of stray electrons (also called “electron clouds” with accelerator beams is important in modern intense-beam accelerators, especially those with beams of positive charge. In magnetic wigglers, used, for instance, for transverse emittance damping, the intense synchrotron radiation produced by the beam can generate an electron cloud of relatively high density. In this paper the complicated dynamics of electron clouds in wigglers is examined using the example of a wiggler in the Cornell Electron Storage Ring Test Accelerator experiment at the Cornell Electron Storage Ring. Three-dimensional particle-in-cell simulations with the WARP-POSINST computer code show different density and dynamics for the electron cloud at locations near the maxima of the vertical wiggler field when compared to locations near the minima. Dynamics in these regions, the electron cloud distribution vs longitudinal position, and the beam coherent tune shift caused by the wiggler electron cloud will be discussed.

Arbitrary amplitude fast electron-acoustic solitons in three-electron component space plasmas

Energy Technology Data Exchange (ETDEWEB)

Mbuli, L. N.; Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); Department of Physics, University of the Western Cape (UWC), Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Bharuthram, R. [Department of Physics, University of the Western Cape (UWC), Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Singh, S. V.; Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India); Department of Physics, University of the Western Cape (UWC), Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa)

2016-06-15

We examine the characteristics of fast electron-acoustic solitons in a four-component unmagnetised plasma model consisting of cool, warm, and hot electrons, and cool ions. We retain the inertia and pressure for all the plasma species by assuming adiabatic fluid behaviour for all the species. By using the Sagdeev pseudo-potential technique, the allowable Mach number ranges for fast electron-acoustic solitary waves are explored and discussed. It is found that the cool and warm electron number densities determine the polarity switch of the fast electron-acoustic solitons which are limited by either the occurrence of fast electron-acoustic double layers or warm and hot electron number density becoming unreal. For the first time in the study of solitons, we report on the coexistence of fast electron-acoustic solitons, in addition to the regular fast electron-acoustic solitons and double layers in our multi-species plasma model. Our results are applied to the generation of broadband electrostatic noise in the dayside auroral region.

Electronic Market and Business: Cyberspace vs. Electronic Environment

Directory of Open Access Journals (Sweden)

Deniss Ščeulovs

2013-12-01

Full Text Available The authors of the article analyze the concept "electronic environment". Having studied a range of academic literature sources and other sources, the authors of the article have drawn a conclusion that the academic writings do not provide a definition of "electronic environment". Furthermore, the various opinions among specialists regarding this concept often differ. Meanwhile, there are several explanations of the term "cyberspace" overlapping the concept of "electronic environment", and these terms are often believed to be synonyms. To understand what the term "electronic environment" means and to properly and correctly employ this concept in entrepreneurship, the authors have performed a lexicographic analysis of this concept by comparing reciprocal concepts. As a result of the research, the authors propose their view on what, in their opinion, "electronic environment" is and what its connection to the concept "cyberspace" is. The topicality of the article lies in the fact that often entrepreneurs and specialists of public and other institutions, when using these terms, imply completely different concepts. It can lead to misunderstanding and misinterpreting the information, as well as to encumbering the understanding of tasks, problems, etc.

Practical XHV electron gun

International Nuclear Information System (INIS)

Urata, Tomohiro; Ishikawa, Tsuyoshi; Cho, Boklae; Oshima, Chuhei

2008-01-01

We have developed practical XHV chambers of a electron gun, of which the operating pressures are 1x10 -9 Pa in a stainless-steel one and 4x10 -9 Pa in a permalloy one. By mounting a noble single-atom electron source with high brightness and high spatial coherence on the electron gun including electron optics, we demonstrated highly collimated electron-beam emission: ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources. In XHV, in addition, we confirmed stable electron emission up to 20 nA, which results in the specimen current high enough for scanning electron microscopes. (author)

Two-Electron Transfer Pathways.

Science.gov (United States)

Lin, Jiaxing; Balamurugan, D; Zhang, Peng; Skourtis, Spiros S; Beratan, David N

2015-06-18

The frontiers of electron-transfer chemistry demand that we develop theoretical frameworks to describe the delivery of multiple electrons, atoms, and ions in molecular systems. When electrons move over long distances through high barriers, where the probability for thermal population of oxidized or reduced bridge-localized states is very small, the electrons will tunnel from the donor (D) to acceptor (A), facilitated by bridge-mediated superexchange interactions. If the stable donor and acceptor redox states on D and A differ by two electrons, it is possible that the electrons will propagate coherently from D to A. While structure-function relations for single-electron superexchange in molecules are well established, strategies to manipulate the coherent flow of multiple electrons are largely unknown. In contrast to one-electron superexchange, two-electron superexchange involves both one- and two-electron virtual intermediate states, the number of virtual intermediates increases very rapidly with system size, and multiple classes of pathways interfere with one another. In the study described here, we developed simple superexchange models for two-electron transfer. We explored how the bridge structure and energetics influence multielectron superexchange, and we compared two-electron superexchange interactions to single-electron superexchange. Multielectron superexchange introduces interference between singly and doubly oxidized (or reduced) bridge virtual states, so that even simple linear donor-bridge-acceptor systems have pathway topologies that resemble those seen for one-electron superexchange through bridges with multiple parallel pathways. The simple model systems studied here exhibit a richness that is amenable to experimental exploration by manipulating the multiple pathways, pathway crosstalk, and changes in the number of donor and acceptor species. The features that emerge from these studies may assist in developing new strategies to deliver multiple

Electron-Electron and Electron-Phonon interactions effects on the tunnel electronic spectrum of PbS quantum dots

Science.gov (United States)

Wang, Hongyue; Lhuillier, Emmanuel; Yu, Qian; Mottaghizadeh, Alireza; Ulysse, Christian; Zimmers, Alexandre; Dubertret, Benoit; Aubin, Herve

2015-03-01

We present a tunnel spectroscopy study of the electronic spectrum of single PbS Quantum Dots (QDs) trapped between nanometer-spaced electrodes, measured at low temperature T=5 K. The carrier filling of the QD can be controlled either by the drain voltage in the shell filling regime or by a gate voltage. In the empty QD, the tunnel spectrum presents the expected signature of the 8x degenerated excited levels. In the drain controlled shell filling regime, the levels degeneracies are lifted by the global electrostatic Coulomb energy of the QD; in the gate controlled shell filling regime, the levels degeneracies are lifted by the intra-Coulomb interactions. In the charged quantum dot, electron-phonons interactions lead to the apparition of Franck-Condon side bands on the single excited levels and possibly Franck Condon blockade at low energy. The sharpening of excited levels at higher gate voltage suggests that the magnitude of electron-phonon interactions is decreased upon increasing the electron filling in the quantum dot. This work was supported by the French ANR Grants 10-BLAN-0409-01, 09-BLAN-0388-01, by the Region Ile-de-France in the framework of DIM Nano-K and by China Scholarship Council.

Electron emitting filaments for electron discharge devices

International Nuclear Information System (INIS)

Leung, K.N.; Pincosy, P.A.; Ehlers, K.W.

1988-01-01

This patent describes an electron emitting device for use in an electron discharge system. It comprises: a filament having a pair of terminal ends, electrical supply means for supplying electrical power to the terminal ends of the filament for directly heating the filament by the passage of an electrical current along the filament between the terminal ends, the filament being substantially tapered in cross section continuously in one direction from one of its pair of terminal ends to another of its pair of terminal ends to achieve uniform heating of the filament along the length thereof by compensating for the nonuniform current along the filament due to the emission of electrons therefrom

Electron irradiation-induced destruction of carbon nanotubes in electron microscopes

International Nuclear Information System (INIS)

Molhave, Kristian; Gudnason, Sven Bjarke; Pedersen, Anders Tegtmeier; Clausen, Casper Hyttel; Horsewell, Andy; Boggild, Peter

2007-01-01

Observations of carbon nanotubes under exposure to electron beam irradiation in standard transmission electron microscope (TEM) and scanning electron microscope (SEM) systems show that such treatment in some cases can cause severe damage of the nanotube structure, even at electron energies far below the approximate 100 keV threshold for knock-on damage displacing carbon atoms in the graphene structure. We find that the damage we observe in one TEM can be avoided by use of a cold finger. This and the morphology of the damage imply that water vapour, which is present as a background gas in many vacuum chambers, can damage the nanotube structure through electron beam-induced chemical reactions. Though, the dependence on the background gas makes these observations specific for the presently used systems, the results demonstrate the importance of careful assessment of the level of subtle structural damage that the individual electron microscope system can do to nanostructures during standard use

Electron-attachment processes

International Nuclear Information System (INIS)

Christophorou, L.G.; McCorkle, D.L.; Christodoulides, A.A.

1982-01-01

Topics covered include: (1) modes of production of negative ions, (2) techniques for the study of electron attachment processes, (3) dissociative electron attachment to ground-state molecules, (4) dissociative electron attachment to hot molecules (effects of temperature on dissociative electron attachment), (5) molecular parent negative ions, and (6) negative ions formed by ion-pair processes and by collisions of molecules with ground state and Rydberg atoms

Acceleration of electrons using an inverse free electron laser auto- accelerator

International Nuclear Information System (INIS)

Wernick, I.K.; Marshall, T.C.

1992-07-01

We present data from our study of a device known as the inverse free electron laser. First, numerical simulations were performed to optimize the design parameters for an experiment that accelerates electrons in the presence of an undulator by stimulated absorption of radiation. The Columbia free electron laser (FEL) was configured as an auto-accelerator (IFELA) system; high power (MW's) FEL radiation at ∼1.65 mm is developed along the first section of an undulator inside a quasi-optical resonator. The electron beam then traverses a second section of undulator where a fraction of the electrons is accelerated by stimulated absorption of the 1.65 mm wavelength power developed in the first undulator section. The second undulator section has very low gain and does not generate power on its own. We have found that as much as 60% of the power generated in the first section can be absorbed in the second section, providing that the initial electron energy is chosen correctly with respect to the parameters chosen for the first and second undulators. An electron momentum spectrometer is used to monitor the distribution of electron energies as the electrons exit the IFELA. We have found; using our experimental parameters, that roughly 10% of the electrons are accelerated to energies as high as 1100 keV, in accordance with predictions from the numerical model. The appearance of high energy electrons is correlated with the abrupt absorption of millimeter power. The autoaccelerator configuration is used because there is no intense source of coherent power at the 1.65 mm design wavelength other than the FEL

Advanced Electronics

Science.gov (United States)

2017-07-21

AFRL-RV-PS- AFRL-RV-PS- TR-2017-0114 TR-2017-0114 ADVANCED ELECTRONICS Ashwani Sharma 21 Jul 2017 Interim Report APPROVED FOR PUBLIC RELEASE...NUMBER Advanced Electronics 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62601F 6. AUTHOR(S) 5d. PROJECT NUMBER 4846 Ashwani Sharma 5e. TASK NUMBER...Approved for public release; distribution is unlimited. (RDMX-17-14919 dtd 20 Mar 2018) 13. SUPPLEMENTARY NOTES 14. ABSTRACT The Space Electronics

The Downshift of Electron Plasma Oscillations in the Electron Foreshock Region.

Science.gov (United States)

1984-10-10

Ii D-Ai50 52 THE DOWNSHIFT OF ELECTRON PLASMA OSCILLATIONS IN THE i/1. ELECTRON FORESHOCK R.. (U) I0MM UNIV 10MM CITY DEPT OF PHYSICS AND ASTRONOMY 5...OSCILLATIONS 0 IN THE ELECTRON FORESHOCK REGION In by S. A. Fuselierl, D. A. Gurnett 1 , Ace NTI 0. and R. J. Fitzenreiter 2 DTI I ,3WERSflY o. 06UNDED ISAI...geleasel Ditibto Unlimited 02 1 16 U. of Iowa 84-21 THE DOWNSHIFT OF ELECTRON PLASMA OSCILLATIONSJ / IN THE ELECTRON FORESHOCK REGION t - by Z I S. A

Electronics engineer's reference book

CERN Document Server

Mazda, F F

1989-01-01

Electronics Engineer's Reference Book, Sixth Edition is a five-part book that begins with a synopsis of mathematical and electrical techniques used in the analysis of electronic systems. Part II covers physical phenomena, such as electricity, light, and radiation, often met with in electronic systems. Part III contains chapters on basic electronic components and materials, the building blocks of any electronic design. Part IV highlights electronic circuit design and instrumentation. The last part shows the application areas of electronics such as radar and computers.

Angular distribution of scattered electron and medium energy electron spectroscopy for metals

International Nuclear Information System (INIS)

Oguri, Takeo; Ishioka, Hisamichi; Fukuda, Hisashi; Irako, Mitsuhiro

1986-01-01

The angular distribution (AD) of scattered electrons produced by medium energy incident electrons (E P = 50 ∼ 300 eV) from polycrystalline Ti, Fe, Ni, Cu and Au were obtained by the angle-resolved medium energy electron spectrometer. The AD of the energy loss peaks are similar figures to AD of the elastically reflected electron peaks. Therefore, the exchanged electrons produced by the knock-on collision between the incident electrons and those of metals without momentum transfer are observed as the energy loss spectra (ELS). This interpretation differs from the inconsequent interpretation by the dielectric theory or the interband transition. The information depth and penetration length are obtained from AD of the Auger electron peaks. The contribution of the surface to spectra is 3 % at the maximum for E P = 50 eV. The true secondary peaks representing the secondary electron emission spectroscopy (SES) are caused by the emissions of the energetic electrons (kT e ≥ 4 eV), and SES is the inversion of ELS. The established fundamental view is that the medium energy electron spectra represent the total bulk density of states. (author)

Wigner-like crystallization of Anderson-localized electron systems with low electron densities

International Nuclear Information System (INIS)

Slutskin, A.A.; Kovtun, H.A.; Pepper, M.

2002-01-01

We consider an electron system under conditions of strong Anderson localization, taking into account interelectron long-range Coulomb repulsion. We establish that at sufficiently low electron densities and sufficiently low temperatures the Coulomb electron interaction brings about ordering of the Anderson-localized electrons into a structure that is close to an ideal (Wigner) crystal lattice, provided the dimension of the system is > 1. This Anderson-Wigner glass (AWG) is a new macroscopic electron state that, on the one hand, is beyond the conventional Fermi glass concept, and on the other hand, qualitatively differs from the known 'plain' Wigner glass (inherent in self-localized electron systems) in that the random slight electron displacements from the ideal crystal sites essentially depend on the electron density. With increasing electron density the AWG is found to turn into the plain Wigner glass or Fermi glass, depending on the width of the random spread of the electron levels. It is shown that the residual disorder of the AWG is characterized by a multi-valley ground-state degeneracy akin to that in a spin glass. Some general features of the AWG are discussed, and a new conduction mechanism of a creep type is predicted

3D Printed structural electronics: embedding and connecting electronic components into freeform electronic devices

NARCIS (Netherlands)

Maalderink, H.H.H.; Bruning, F.B.J.; Schipper, M.M.R. de; Werff, J.J.J. van der; Germs, W.W.C.; Remmers, J.J.C.; Meinders, E.R.

2018-01-01

The need for personalised and smart products drives the development of structural electronics with mass-customisation capability. A number of challenges need to be overcome in order to address the potential of complete free form manufacturing of electronic devices. One key challenge is the

3D Printed structural electronics : embedding and connecting electronic components into freeform electronic devices

NARCIS (Netherlands)

Maalderink, H.H.; Bruning, F.B.J.; de Schipper, M.R.; van der Werff, J.J.; Germs, W.C.; Remmers, J.J.C.; Meinders, E.R.

2018-01-01

The need for personalised and smart products drives the development of structural electronics with mass-customisation capability. A number of challenges need to be overcome in order to address the potential of complete free form manufacturing of electronic devices. One key challenge is the

27 CFR 73.32 - May I electronically sign forms I submit electronically to TTB?

Science.gov (United States)

2010-04-01

... AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY (CONTINUED) PROCEDURES AND PRACTICES ELECTRONIC SIGNATURES; ELECTRONIC SUBMISSION OF FORMS Electronic Filing of Documents with TTB § 73.32 May I electronically sign forms I submit electronically to TTB? You may electronically sign the electronic form you...

Electron Bifurcation: Thermodynamics and Kinetics of Two-Electron Brokering in Biological Redox Chemistry.

Science.gov (United States)

Zhang, Peng; Yuly, Jonathon L; Lubner, Carolyn E; Mulder, David W; King, Paul W; Peters, John W; Beratan, David N

2017-09-19

How can proteins drive two electrons from a redox active donor onto two acceptors at very different potentials and distances? And how can this transaction be conducted without dissipating very much energy or violating the laws of thermodynamics? Nature appears to have addressed these challenges by coupling thermodynamically uphill and downhill electron transfer reactions, using two-electron donor cofactors that have very different potentials for the removal of the first and second electron. Although electron bifurcation is carried out with near perfection from the standpoint of energy conservation and electron delivery yields, it is a biological energy transduction paradigm that has only come into focus recently. This Account provides an exegesis of the biophysical principles that underpin electron bifurcation. Remarkably, bifurcating electron transfer (ET) proteins typically send one electron uphill and one electron downhill by similar energies, such that the overall reaction is spontaneous, but not profligate. Electron bifurcation in the NADH-dependent reduced ferredoxin: NADP + oxidoreductase I (Nfn) is explored in detail here. Recent experimental progress in understanding the structure and function of Nfn allows us to dissect its workings in the framework of modern ET theory. The first electron that leaves the two-electron donor flavin (L-FAD) executes a positive free energy "uphill" reaction, and the departure of this electron switches on a second thermodynamically spontaneous ET reaction from the flavin along a second pathway that moves electrons in the opposite direction and at a very different potential. The singly reduced ET products formed from the bifurcating flavin are more than two nanometers distant from each other. In Nfn, the second electron to leave the flavin is much more reducing than the first: the potentials are said to be "crossed." The eventually reduced cofactors, NADH and ferredoxin in the case of Nfn, perform crucial downstream redox

Electronic Elections

DEFF Research Database (Denmark)

Schürmann, Carsten

2009-01-01

Electronic voting technology is a two edged sword. It comes with many risks but brings also many benefits. Instead of flat out rejecting the technology as uncontrollably dangerous, we advocate in this paper a different technological angle that renders electronic elections trustworthy beyond...... the usual levels of doubt. We exploit the trust that voters currently have into the democratic process and model our techniques around that observation accordingly. In particular, we propose a technique of trace emitting computations to record the individual steps of an electronic voting machine...... for a posteriori validation on an acceptably small trusted computing base. Our technology enables us to prove that an electronic elections preserves the voter’s intent, assuming that the voting machine and the trace verifier are independent....

Low-dose electron energy-loss spectroscopy using electron counting direct detectors.

Science.gov (United States)

Maigné, Alan; Wolf, Matthias

2018-03-01

Since the development of parallel electron energy loss spectroscopy (EELS), charge-coupled devices (CCDs) have been the default detectors for EELS. With the recent development of electron-counting direct-detection cameras, micrographs can be acquired under very low electron doses at significantly improved signal-to-noise ratio. In spectroscopy, in particular in combination with a monochromator, the signal can be extremely weak and the detection limit is principally defined by noise introduced by the detector. Here we report the use of an electron-counting direct-detection camera for EEL spectroscopy. We studied the oxygen K edge of amorphous ice and obtained a signal noise ratio up to 10 times higher than with a conventional CCD.We report the application of electron counting to record time-resolved EEL spectra of a biological protein embedded in amorphous ice, revealing chemical changes observed in situ while exposed by the electron beam. A change in the fine structure of nitrogen K and the carbon K edges were recorded during irradiation. A concentration of 3 at% nitrogen was detected with a total electron dose of only 1.7 e-/Å2, extending the boundaries of EELS signal detection at low electron doses.

How do electron localization functions describe π-electron delocalization?

Science.gov (United States)

Steinmann, Stephan N; Mo, Yirong; Corminboeuf, Clemence

2011-12-14

Scalar fields provide an intuitive picture of chemical bonding. In particular, the electron localization function (ELF) has proven to be highly valuable in interpreting a broad range of bonding patterns. The discrimination between enhanced or reduced electron (de)localization within cyclic π-conjugated systems remains, however, challenging for ELF. In order to clearly distinguish between the local properties of ten highly and weakly π-(de)localized prototype systems, we compare the ELFs of both the canonical wave functions and electron-localized states (diabatic) with those of two closely related scalar fields: the electron localizability indicator (ELI-D) and the localized orbital locator (LOL). The simplest LOL function distinguishes enhanced from weak π-(de)localization in an insightful and reliable manner. LOL offers the finest contrast between annulenes with 4n/4n + 2 π electrons and their inorganic analogues as well as between hyperconjugated cyclopentadiene derivatives. LOL(π) also gives an appealing and intuitive picture of the π-bond. In contrast, the most popular ELF fails to capture subtle contrasting local electronic properties and suffers from the arbitrariness of the σ/π dissection. The orbital separation of the most recent ELI-D is clear-cut but the interpretations sometime less straightforward in the present context.

Electron shuttles in biotechnology.

Science.gov (United States)

Watanabe, Kazuya; Manefield, Mike; Lee, Matthew; Kouzuma, Atsushi

2009-12-01

Electron-shuttling compounds (electron shuttles [ESs], or redox mediators) are essential components in intracellular electron transfer, while microbes also utilize self-produced and naturally present ESs for extracellular electron transfer. These compounds assist in microbial energy metabolism by facilitating electron transfer between microbes, from electron-donating substances to microbes, and/or from microbes to electron-accepting substances. Artificially supplemented ESs can create new routes of electron flow in the microbial energy metabolism, thereby opening up new possibilities for the application of microbes to biotechnology processes. Typical examples of such processes include halogenated-organics bioremediation, azo-dye decolorization, and microbial fuel cells. Herein we suggest that ESs can be applied widely to create new microbial biotechnology processes.

Treatment of foods with 'soft-electrons' (low-energy electrons)

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Toru [Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki (Japan); Todoriki, Setsuko [National Food Research Institute (NFRI), Tsukuba, Ibaraki (Japan)

2003-02-01

Electrons with energies of 300 keV or lower were defined as soft-electrons'. Soft-electrons can eradicate microorganisms residing on the surface of grains, pulses, spices, dehydrated vegetables, tea leaves and seeds, and reduce their microbial loads to levels lower than 10 CFU/g with little quality deterioration. Soft-electrons can inactivate insect pests infesting grains and pulses and inhibit sprouting of potatoes. (author)

An inventory of indigenous plants used as anthelmintics in Amathole ...

African Journals Online (AJOL)

Results: Medicinal plants mostly used for traditional management of intestinal worms were selected from 13 plant families: Alliaceae, Anacardiaceae, Asphodelaceae, Asteraceae, Crassulaceae, Dracaenaceae, Fabaceae, Hypoxidaceae, Lamiaceae, Longaniaceae, Punicaceae, Polygonaceae, and Verbenaceae. Out of ...

Electron beam collimation with a photon MLC for standard electron treatments

Science.gov (United States)

Mueller, S.; Fix, M. K.; Henzen, D.; Frei, D.; Frauchiger, D.; Loessl, K.; Stampanoni, M. F. M.; Manser, P.

2018-01-01

Standard electron treatments are currently still performed using standard or molded patient-specific cut-outs placed in the electron applicator. Replacing cut-outs and electron applicators with a photon multileaf collimator (pMLC) for electron beam collimation would make standard electron treatments more efficient and would facilitate advanced treatment techniques like modulated electron radiotherapy (MERT) and mixed beam radiotherapy (MBRT). In this work, a multiple source Monte Carlo beam model for pMLC shaped electron beams commissioned at a source-to-surface distance (SSD) of 70 cm is extended for SSDs of up to 100 cm and validated for several Varian treatment units with field sizes typically used for standard electron treatments. Measurements and dose calculations agree generally within 3% of the maximal dose or 2 mm distance to agreement. To evaluate the dosimetric consequences of using pMLC collimated electron beams for standard electron treatments, pMLC-based and cut-out-based treatment plans are created for a left and a right breast boost, a sternum, a testis and a parotid gland case. The treatment plans consist of a single electron field, either alone (1E) or in combination with two 3D conformal tangential photon fields (1E2X). For each case, a pMLC plan with similar treatment plan quality in terms of dose homogeneity to the target and absolute mean dose values to the organs at risk (OARs) compared to a cut-out plan is found. The absolute mean dose to an OAR is slightly increased for pMLC-based compared to cut-out-based 1E plans if the OAR is located laterally close to the target with respect to beam direction, or if a 6 MeV electron beam is used at an extended SSD. In conclusion, treatment plans using cut-out collimation can be replaced by plans of similar treatment plan quality using pMLC collimation with accurately calculated dose distributions.

Technical report of electronics shop characteristics of high speed electronics component, (1)

International Nuclear Information System (INIS)

Watanabe, Shin-ichi; Shiino, Kazuo.

1975-01-01

We must develop electronics circuits for high speed signals. The electronics components of the circuits make use of the special components. This report treats a pulse response of the electronics components (i.e. coaxial cable, connector, resistor, capacitor, diode, transistor) for high speed electronics. The results of this report was already applied constructions of high speed electronics circuits and experimental equipments of the High Energy Physics Division. (auth.)

Fully printable, strain-engineered electronic wrap for customizable soft electronics.

Science.gov (United States)

Byun, Junghwan; Lee, Byeongmoon; Oh, Eunho; Kim, Hyunjong; Kim, Sangwoo; Lee, Seunghwan; Hong, Yongtaek

2017-03-24

Rapid growth of stretchable electronics stimulates broad uses in multidisciplinary fields as well as industrial applications. However, existing technologies are unsuitable for implementing versatile applications involving adaptable system design and functions in a cost/time-effective way because of vacuum-conditioned, lithographically-predefined processes. Here, we present a methodology for a fully printable, strain-engineered electronic wrap as a universal strategy which makes it more feasible to implement various stretchable electronic systems with customizable layouts and functions. The key aspects involve inkjet-printed rigid island (PRI)-based stretchable platform technology and corresponding printing-based automated electronic functionalization methodology, the combination of which provides fully printed, customized layouts of stretchable electronic systems with simplified process. Specifically, well-controlled contact line pinning effect of printed polymer solution enables the formation of PRIs with tunable thickness; and surface strain analysis on those PRIs leads to the optimized stability and device-to-island fill factor of strain-engineered electronic wraps. Moreover, core techniques of image-based automated pinpointing, surface-mountable device based electronic functionalizing, and one-step interconnection networking of PRIs enable customized circuit design and adaptable functionalities. To exhibit the universality of our approach, multiple types of practical applications ranging from self-computable digital logics to display and sensor system are demonstrated on skin in a customized form.

Fully printable, strain-engineered electronic wrap for customizable soft electronics

Science.gov (United States)

Byun, Junghwan; Lee, Byeongmoon; Oh, Eunho; Kim, Hyunjong; Kim, Sangwoo; Lee, Seunghwan; Hong, Yongtaek

2017-03-01

Rapid growth of stretchable electronics stimulates broad uses in multidisciplinary fields as well as industrial applications. However, existing technologies are unsuitable for implementing versatile applications involving adaptable system design and functions in a cost/time-effective way because of vacuum-conditioned, lithographically-predefined processes. Here, we present a methodology for a fully printable, strain-engineered electronic wrap as a universal strategy which makes it more feasible to implement various stretchable electronic systems with customizable layouts and functions. The key aspects involve inkjet-printed rigid island (PRI)-based stretchable platform technology and corresponding printing-based automated electronic functionalization methodology, the combination of which provides fully printed, customized layouts of stretchable electronic systems with simplified process. Specifically, well-controlled contact line pinning effect of printed polymer solution enables the formation of PRIs with tunable thickness; and surface strain analysis on those PRIs leads to the optimized stability and device-to-island fill factor of strain-engineered electronic wraps. Moreover, core techniques of image-based automated pinpointing, surface-mountable device based electronic functionalizing, and one-step interconnection networking of PRIs enable customized circuit design and adaptable functionalities. To exhibit the universality of our approach, multiple types of practical applications ranging from self-computable digital logics to display and sensor system are demonstrated on skin in a customized form.

Electrons in Nanostructures

DEFF Research Database (Denmark)

Flindt, Christian

2007-01-01

in the possibilities o®ered by the quantum mechanical behavior of electrons when it comes to informa- tion processing. This branch of research is also concerned with fundamental questions in physics. Besides an introduction to the above-mentioned subjects, the thesis con- tains a number of contributions to the ¯elds...... of coherent electron manip- ulation and the statistical description of electron transport through nano- devices. The physics of the electrons are described with a combination of numerical methods, developed and applied in the thesis, and more analytical approaches, which are also discussed. The thesis......-based communication. The statistical description of electron transport through nanostructures is based on rate equations, and the primary contribution of the thesis in that respect is the development of a method that allows for the calculation of the distribution of electrons passing through a device. The method...

Identification of electrons in the ZEUS hadron-electron separator with neural networks

International Nuclear Information System (INIS)

Carstens, J.O.

1994-10-01

An electron finder for the ZEUS experiment was constructed, which is specialized to electrons in the momentum range 0.5 to 3.0 GeV/c. For the first time this electron finder connects the informations of the calorimeter with those of the hadron-electron separator (HES). For this purpose the electron finder was equipped with a neural network. The electron finder reached on a data set of photoproduction events with conversion electrons an efficiency and discriminance of E=(62.9±2.2±0.6)% and D=(91.4±0.8±1.1)%. From these two quantities it can be calculated that the electron finder the ratio electrons to background increases by the factoe E/(1-D)=7.4 (Signal amplification). For the comparison: A neural net, to which only calorimeter informations have been made available, reached at the same efficiency a signal amplification of 2.4. A simple cut in the variable HES-signal reaches a signal amplification of 6.3. Hints were given, how training data sets with electrons and hadrons of higher energies can be obtained. With such data sets the working range of the electron finder can be without problems extended to higher momenta. As preparation for the construction of the electron finder an introduction to the foundations of the mathematics and the application of neural networks was given. By means of examples different methods for the convergence improvement have been tested. Numerous representations mediate illustrative imaginations on the mathematical process of the training of neural networks

Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

Energy Technology Data Exchange (ETDEWEB)

Weathersby, S. P.; Brown, G.; Chase, T. F.; Coffee, R.; Corbett, J.; Eichner, J. P.; Frisch, J. C.; Fry, A. R.; Gühr, M.; Hartmann, N.; Hast, C.; Hettel, R.; Jobe, R. K.; Jongewaard, E. N.; Lewandowski, J. R.; Li, R. K., E-mail: lrk@slac.stanford.edu; Lindenberg, A. M.; Makasyuk, I.; May, J. E.; McCormick, D. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); and others

2015-07-15

Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

Secondary electron emission anisotropy in oblique incidence of electrons on the (100) Mo

International Nuclear Information System (INIS)

Gomoyunova, M.V.; Zaslavskij, S.L.; Pronin, I.I.

1978-01-01

Studied was the influence of azimuthal plane of incidence of primary particles with energies of 0.5-1.5 keV on the secondary electron emission of the (100) Mo face at the constant polar angle of 45 deg. The measurements were carried out in vacuum of (2-4)x10 -10 torr by modulation technique. It is shown that anisotropy is peculiar to the secondary electron emission of all energies. The anisotropy of emission has two maxima; the high-energy maximum connected with reflected primary electrons and situated near the elastically reflected electrons and weaker pronounced the low-energy one which is found at energies of 100-200 eV and is conditioned by truly secondary electrons. It is shown that the anisotropy, characterizing secondary electrons responsible for the appearance of structure in spectrum, particularly the Auger electrons and the electrons suffering ionizing energy losses, exceeds the anisotropy of continuous spectrum electrons possessing the same energy. The electron diffraction dynamic theory, based on the conception of the united wave field of electrons, has been used to explain the regularities stated

Kinetic and electron-electron energies for convex sums of ground state densities with degeneracies and fractional electron number

Energy Technology Data Exchange (ETDEWEB)

Levy, Mel, E-mail: ayers@mcmaster.ca, E-mail: mlevy@tulane.edu [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Department of Physics, North Carolina A and T State University, Greensboro, North Carolina 27411 (United States); Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States); Anderson, James S. M.; Zadeh, Farnaz Heidar; Ayers, Paul W., E-mail: ayers@mcmaster.ca, E-mail: mlevy@tulane.edu [Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario (Canada)

2014-05-14

Properties of exact density functionals provide useful constraints for the development of new approximate functionals. This paper focuses on convex sums of ground-level densities. It is observed that the electronic kinetic energy of a convex sum of degenerate ground-level densities is equal to the convex sum of the kinetic energies of the individual degenerate densities. (The same type of relationship holds also for the electron-electron repulsion energy.) This extends a known property of the Levy-Valone Ensemble Constrained-Search and the Lieb Legendre-Transform refomulations of the Hohenberg-Kohn functional to the individual components of the functional. Moreover, we observe that the kinetic and electron-repulsion results also apply to densities with fractional electron number (even if there are no degeneracies), and we close with an analogous point-wise property involving the external potential. Examples where different degenerate states have different kinetic energy and electron-nuclear attraction energy are given; consequently, individual components of the ground state electronic energy can change abruptly when the molecular geometry changes. These discontinuities are predicted to be ubiquitous at conical intersections, complicating the development of universally applicable density-functional approximations.

Embracing Electronic Publishing.

Science.gov (United States)

Wills, Gordon

1996-01-01

Electronic publishing is the grandest revolution in the capture and dissemination of academic and professional knowledge since Caxton developed the printing press. This article examines electronic publishing, describes different electronic publishing scenarios (authors' cooperative, consolidator/retailer/agent oligopsony, publisher oligopoly), and…

Peptide π-Electron Conjugates: Organic Electronics for Biology?

Science.gov (United States)

Ardoña, Herdeline Ann M; Tovar, John D

2015-12-16

Highly ordered arrays of π-conjugated molecules are often viewed as a prerequisite for effective charge-transporting materials. Studies involving these materials have traditionally focused on organic electronic devices, with more recent emphasis on biological systems. In order to facilitate the transition to biological environments, biomolecules that can promote hierarchical ordering and water solubility are often covalently appended to the π-electron unit. This review highlights recent work on π-conjugated systems bound to peptide moieties that exhibit self-assembly and aims to provide an overview on the development and emerging applications of peptide-based supramolecular π-electron systems.

Anatomía foliar y del pecíolo de cuatro especies de Lupinus (Fabaceae Foliar and petiole anatomy of four species of Lupinus (Fabaceae

Directory of Open Access Journals (Sweden)

Juan Francisco Zamora-Natera

2012-09-01

Full Text Available Se describe y compara la anatomía foliar y del pecíolo de 4 especies del género Lupinus (L. aschenbornii S.Schauer, L. exaltatus Zucc., L. montanus Kunth y L. reflexus Rose que se distribuyen en un gradiente altitudinal en el Parque Nacional Nevado de Colima. Las hojas se fijaron en campo y se procesaron mediante la técnica de inclusión en parafina. Parte de las láminas se deshidrataron para caracterizar la superficie foliar por medio del microscopio electrónico de barrido. Las especies comparten la epidermis papilosa de paredes anticlinales con diferentes grados de ondulación, estomas anomocíticos, tricomas simples lineares y mesofilo bifacial. Los folíolos de L. montanus son glabros en la superficie abaxial, las estrías cuticulares sobre las células localizadas en la base de los tricomas es un rasgo característico de L. montanus y de L. reflexus. Las diferencias encontradas en espesor de la lámina y del mesofilo así como la abundancia de ceras epicuticulares pueden estar influenciadas por el ambiente. Distintivamente, el número y distribución de haces vasculares en los pecíolos difieren entre las 4 especies y podrían ser de utilidad para diferenciarlas si estos resultados se confirman al estudiar un mayor número de especies de Lupinus.The aims of this study were to describe and compare the foliar and petiole anatomy of 4 species of Lupinus (L. aschenbornii S.Schauer, L. exaltatus Zucc., L. montanus Kunth, and L. reflexus Rose distributed in an elevation gradient at Parque Nacional Nevado de Colima. Leaves were fixed in the field and prepared using the paraffin embedding technique. In addition, part of the blades was dehydrated to describe leaf surface through the scanning electron microscope. The 4 species shared a papillose epidermis with undulated anticlinal walls in different degrees, stomata anomocytic, simple unicellular trichomes, and bifacial mesophyll. Leaflets of L. montanus are glabrous on the abaxial surface

Modified Sternglass theory for the emission of secondary electrons by fast-electron impact

International Nuclear Information System (INIS)

Suszcynsky, D.M.; Borovsky, J.E.

1992-01-01

The Sternglass theory [Sternglass, Phys. Rev. 108, 1 (1957)] for fast-ion-induced secondary-electron emission from metals has been modified to predict the secondary-electron yield from metals impacted by energetic (several keV to about 200 keV) electrons. The primary modification of the theory accounts for the contribution of the backscattered electrons to the production of secondary electrons based on a knowledge of the backscattered-electron energy distribution. The modified theory is in reasonable agreement with recent experimental data from gold targets in the 6--30-keV electron energy range

Calculation of the electron trajectory for 200 kV self-shielded electron accelerator

International Nuclear Information System (INIS)

Wang Shuiqing

2000-01-01

In order to calculate the electron trajectory of 200 kV self-shielded electron accelerator, the electric field is calculated with a TRAJ program. In this program, following electron track mash points one by one, the electron beam trajectories are calculated. Knowing the effect of grid voltage on electron optics and gaining grid voltage focusing effect in the various energy grades, the authors have gained scientific basis for adjusting grid voltage, and also accumulated a wealth of experience for designing self-shielded electron accelerator or electron curtain in future

Electronic inventions and discoveries electronics from its earliest beginnings to the present day

CERN Document Server

Dummer, G W A

1983-01-01

Electronic Inventions and Discoveries: Electronics from Its Earliest Beginnings to the Present Day provides a summary of the development of the whole field of electronics. Organized into 13 chapters, the book covers and reviews the history of electronics as a whole and its aspects. The opening chapter covers the beginnings of electronics, while the next chapter discusses the development of components, transistors, and integrated circuits. The third chapter tackles the expansion of electronics and its effects on industry. The succeeding chapters discuss the history of the aspects of electronics

Attosecond electron pulse trains and quantum state reconstruction in ultrafast transmission electron microscopy

Science.gov (United States)

Priebe, Katharina E.; Rathje, Christopher; Yalunin, Sergey V.; Hohage, Thorsten; Feist, Armin; Schäfer, Sascha; Ropers, Claus

2017-12-01

Ultrafast electron and X-ray imaging and spectroscopy are the basis for an ongoing revolution in the understanding of dynamical atomic-scale processes in matter. The underlying technology relies heavily on laser science for the generation and characterization of ever shorter pulses. Recent findings suggest that ultrafast electron microscopy with attosecond-structured wavefunctions may be feasible. However, such future technologies call for means to both prepare and fully analyse the corresponding free-electron quantum states. Here, we introduce a framework for the preparation, coherent manipulation and characterization of free-electron quantum states, experimentally demonstrating attosecond electron pulse trains. Phase-locked optical fields coherently control the electron wavefunction along the beam direction. We establish a new variant of quantum state tomography—`SQUIRRELS'—for free-electron ensembles. The ability to tailor and quantitatively map electron quantum states will promote the nanoscale study of electron-matter entanglement and new forms of ultrafast electron microscopy down to the attosecond regime.

Digital electronics

CERN Document Server

Morris, John

2013-01-01

An essential companion to John C Morris's 'Analogue Electronics', this clear and accessible text is designed for electronics students, teachers and enthusiasts who already have a basic understanding of electronics, and who wish to develop their knowledge of digital techniques and applications. Employing a discovery-based approach, the author covers fundamental theory before going on to develop an appreciation of logic networks, integrated circuit applications and analogue-digital conversion. A section on digital fault finding and useful ic data sheets completes th

The magnetized electron-acoustic instability driven by a warm, field-aligned electron beam

International Nuclear Information System (INIS)

Sooklal, A.; Mace, R.L.

2004-01-01

The electron-acoustic instability in a magnetized plasma having three electron components, one of which is a field-aligned beam of intermediate temperature, is investigated. When the plasma frequency of the cool electrons exceeds the electron gyrofrequency, the electron-acoustic instability 'bifurcates' at sufficiently large propagation angles with respect to the magnetic field to yield an obliquely propagating, low-frequency electron-acoustic instability and a higher frequency cyclotron-sound instability. Each of these instabilities retains certain wave features of its progenitor, the quasiparallel electron-acoustic instability, but displays also new magnetic qualities through its dependence on the electron gyrofrequency. The obliquely propagating electron-acoustic instability requires a lower threshold beam speed for its excitation than does the cyclotron-sound instability, and for low to intermediate beam speeds has the higher maximum growth rate. When the plasma is sufficiently strongly magnetized that the plasma frequency of the cool electrons is less than the electron gyrofrequency, the only instability in the electron-acoustic frequency range is the strongly magnetized electron-acoustic instability. Its growth rate and real frequency exhibit a monotonic decrease with wave propagation angle and it grows at small to intermediate wave numbers where its parallel phase speed is approximately constant. The relevance of the results to the interpretation of cusp auroral hiss and auroral broadband electrostatic noise is briefly discussed

Starting electronics all you need to get a grounding in practical electronics

CERN Document Server

Brindley, Keith

2013-01-01

Starting Electronics is a nine-chapter introductory text to electronics based on feature articles previously published as magazine articles. The opening chapter provides an overview of the fundamentals of electronics. The succeeding chapters present details of some easy-to-do experiments and the current and voltage measurement. The remaining chapters cover some basic components of electronics, including capacitor, integrated circuit, oscillator, filter, diodes, and transistors. This book will prove useful to electronic constructors and students.

Single Electron Tunneling

International Nuclear Information System (INIS)

Ruggiero, Steven T.

2005-01-01

Financial support for this project has led to advances in the science of single-electron phenomena. Our group reported the first observation of the so-called ''Coulomb Staircase'', which was produced by tunneling into ultra-small metal particles. This work showed well-defined tunneling voltage steps of width e/C and height e/RC, demonstrating tunneling quantized on the single-electron level. This work was published in a now well-cited Physical Review Letter. Single-electron physics is now a major sub-field of condensed-matter physics, and fundamental work in the area continues to be conducted by tunneling in ultra-small metal particles. In addition, there are now single-electron transistors that add a controlling gate to modulate the charge on ultra-small photolithographically defined capacitive elements. Single-electron transistors are now at the heart of at least one experimental quantum-computer element, and single-electron transistor pumps may soon be used to define fundamental quantities such as the farad (capacitance) and the ampere (current). Novel computer technology based on single-electron quantum dots is also being developed. In related work, our group played the leading role in the explanation of experimental results observed during the initial phases of tunneling experiments with the high-temperature superconductors. When so-called ''multiple-gap'' tunneling was reported, the phenomenon was correctly identified by our group as single-electron tunneling in small grains in the material. The main focus throughout this project has been to explore single electron phenomena both in traditional tunneling formats of the type metal/insulator/particles/insulator/metal and using scanning tunneling microscopy to probe few-particle systems. This has been done under varying conditions of temperature, applied magnetic field, and with different materials systems. These have included metals, semi-metals, and superconductors. Amongst a number of results, we have

Electron transfer from nucleobase electron adducts to 5-bromouracil. Is guanine an ultimate sink for the electron in irradiated DNA?

International Nuclear Information System (INIS)

Nese, C.; Yuan, Z.; Schuchmann, M.N.; Sonntag, C. von

1992-01-01

Electron transfer to 5-bromouracil (5-BrU) from nucleobase (N) electron adducts (and their protonated forms) has been studied by product analysis and pulse radiolysis. When an electron is transferred to 5-BrU, the ensuing 5-BrU radical anion rapidly loses a bromide ion; the uracilyl radical thus formed reacts with added t-butanol, yielding uracil. From the uracil yields measured as the function of [N]/[5-BrU] after γ-radiolysis of Ar-saturated solutions it is concluded that thymine and adenine electron adducts and their heteroatom-protonated forms transfer electrons quantitatively to 5-BrU. The data raise the question whether in DNA the guanine moiety may act as the ultimate sink of the electron in competition with other processes such as protonation at C(6) of the thymine electron adduct. (Author)

Extreme environment electronics

CERN Document Server

Cressler, John D

2012-01-01

Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp

Electron-vibrational transitions under molecular ions collisions with slow electrons

International Nuclear Information System (INIS)

Andreev, E.A.

1993-01-01

A concept of a multichannel quantum defect is considered and basic theoretic ratios of inelastic collisional processes with the participation of molecular positive ions and slow electrons playing an important role both in atmospheric and laboratory plasma, are presented. The problem of scattering channel number limitation with the provision of S-matrix unique character is considered. Different models of electron rotation-vibrational connection under collision of two-atom molecular ions with slow electrons are analysed. Taking N 2 + as an example, a high efficiency of transitions between different electron states of a molecular ion is shown. 73 refs., 9 figs., 1 tab

Electron: Cluster interactions

International Nuclear Information System (INIS)

Scheidemann, A.A.; Knight, W.D.

1994-02-01

Beam depletion spectroscopy has been used to measure absolute total inelastic electron-sodium cluster collision cross sections in the energy range from E ∼ 0.1 to E ∼ 6 eV. The investigation focused on the closed shell clusters Na 8 , Na 20 , Na 40 . The measured cross sections show an increase for the lowest collision energies where electron attachment is the primary scattering channel. The electron attachment cross section can be understood in terms of Langevin scattering, connecting this measurement with the polarizability of the cluster. For energies above the dissociation energy the measured electron-cluster cross section is energy independent, thus defining an electron-cluster interaction range. This interaction range increases with the cluster size

Role of electron-electron scattering on spin transport in single layer graphene

Directory of Open Access Journals (Sweden)

Bahniman Ghosh

2014-01-01

Full Text Available In this work, the effect of electron-electron scattering on spin transport in single layer graphene is studied using semi-classical Monte Carlo simulation. The D’yakonov-P’erel mechanism is considered for spin relaxation. It is found that electron-electron scattering causes spin relaxation length to decrease by 35% at 300 K. The reason for this decrease in spin relaxation length is that the ensemble spin is modified upon an e-e collision and also e-e scattering rate is greater than phonon scattering rate at room temperature, which causes change in spin relaxation profile due to electron-electron scattering.

ELECTRONIC SIGNATURES

African Journals Online (AJOL)

10332324

"[to] promote the understanding and, acceptance of and growth in the number of electronic transactions .... Chapter III of the ECT Act is based on the UNCITRAL Model Law on Electronic. Commerce ... Communications Technology Law 146. 22.

Starting electronics

CERN Document Server

Brindley, Keith

2005-01-01

Starting Electronics is unrivalled as a highly practical introduction for hobbyists, students and technicians. Keith Brindley introduces readers to the functions of the main component types, their uses, and the basic principles of building and designing electronic circuits. Breadboard layouts make this very much a ready-to-run book for the experimenter; and the use of multimeter, but not oscilloscopes, puts this practical exploration of electronics within reach of every home enthusiast's pocket. The third edition has kept the simplicity and clarity of the original. New material

Stretchable electronics

CERN Document Server

Someya, Takao

2012-01-01

With its comprehensive coverage this handbook and ready reference brings together some of the most outstanding scientists in the field to lay down the undisputed knowledge on how to make electronics stretchable.As such, it focuses on gathering and evaluating the materials, designs, models and technologies that enable the fabrication of fully elastic electronic devices which can sustain high strain. Furthermore, it provides a review of those specific applications that directly benefit from highly compliant electronics, including transistors, photonic devices and sensors. In addition to stre

Coherent electron cooling

Energy Technology Data Exchange (ETDEWEB)

Litvinenko,V.

2009-05-04

Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

Electronics pocket book

CERN Document Server

Parr, E A

1981-01-01

Electronics Pocket Book, Fourth Edition is a nonmathematical presentation of the many varied topics covered by electronics. The book tackles electron physics, electronic components (i.e. resistors, capacitors, and conductors), integrated circuits, and the principles of a.c. and d.c. amplifiers. The text also discusses oscillators, digital circuits, digital computers, and optoelectronics (i.e., sensors, emitters, and devices that utilize light). Communications (such as line and radio communications, transmitters, receivers, and digital techniques); the principles and examples of servosystems; a

Sticker electronics

KAUST Repository

Hussain, Muhammad Mustafa; Torres Sevilla, Galo Andres; Diaz Cordero, Marlon Steven

2017-01-01

Electronic stickers may be manufactured on flexible substrates (110, 120, 130) as layers and packaged together. The package may then have an adhesive applied to one side to provide capability for sticking the electronic devices to surfaces

Electronics for LHC Experiments

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-07-01

This document gathers the abstracts of most presentations made at this workshop on electronics for the large hadron collider (LHC) experiments. The presentations were arranged into 6 sessions: 1) electronics for tracker, 2) trigger electronics, 3) detector control systems, 4) data acquisition, 5) electronics for calorimeters and electronics for muons, and 6) links, power systems, grounding and shielding, testing and quality assurance.

Electronics for LHC Experiments

International Nuclear Information System (INIS)

2004-01-01

This document gathers the abstracts of most presentations made at this workshop on electronics for the large hadron collider (LHC) experiments. The presentations were arranged into 6 sessions: 1) electronics for tracker, 2) trigger electronics, 3) detector control systems, 4) data acquisition, 5) electronics for calorimeters and electronics for muons, and 6) links, power systems, grounding and shielding, testing and quality assurance

Electron Bernstein wave electron temperature profile diagnostic (invited)

International Nuclear Information System (INIS)

Taylor, G.; Efthimion, P.; Jones, B.; Munsat, T.; Spaleta, J.; Hosea, J.; Kaita, R.; Majeski, R.; Menard, J.

2001-01-01

Electron cyclotron emission (ECE) has been employed as a standard electron temperature profile diagnostic on many tokamaks and stellarators, but most magnetically confined plasma devices cannot take advantage of standard ECE diagnostics to measure temperature. They are either ''overdense,'' operating at high density relative to the magnetic field (e.g., ω pe >>Omega ce in a spherical torus) or they have insufficient density and temperature to reach the blackbody condition (τ>2). Electron Bernstein waves (EBWs) are electrostatic waves that can propagate in overdense plasmas and have a high optical thickness at the electron cyclotron resonance layers as a result of their large k perp . In this article we report on measurements of EBW emission on the CDX-U spherical torus, where B 0 ∼2kG, e >∼10 13 cm -3 and T e ∼10--200eV. Results are presented for electromagnetic measurements of EBW emission, mode converted near the plasma edge. The EBW emission was absolutely calibrated and compared to the electron temperature profile measured by a multipoint Thomson scattering diagnostic. Depending on the plasma conditions, the mode-converted EBW radiation temperature was found to be ≤T e and the emission source was determined to be radially localized at the electron cyclotron resonance layer. A Langmuir triple probe and a 140 GHz interferometer were employed to measure changes in the edge density profile in the vicinity of the upper hybrid resonance where the mode conversion of the EBWs is expected to occur. Initial results suggest EBW emission and EBW heating are viable concepts for plasmas where ω pe >>Omega ce

Electron energy distribution from intense electron beams in the upper mesosphere and lower thermosphere

International Nuclear Information System (INIS)

Martinez-Sanchez, M.; Cheng, Wai; Dvore, D.; Zahniser, M.S.

1992-01-01

A model was developed to calculate the electron energy spectrum created by an electron beam in the upper atmosphere. A significant feature of the model is the inclusion of the effects of electron-electron collisions which are important at high beam intensity when the ratio of the electron to ambient gas density is high. Comparing the calculated results for a 2.6-kV, 20-A beam at 110-km altitude from models with and without the electron-electron collision term, the electron-electron collisions have the effect of smoothing out the electron spectrum in the low-energy region ( 2 and O 2 are filled in, resulting in an increase in the calculated production rate of these species compared with model calculations that neglect this effect

Interaction of electrons with light metal hydrides in the transmission electron microscope.

Science.gov (United States)

Wang, Yongming; Wakasugi, Takenobu; Isobe, Shigehito; Hashimoto, Naoyuki; Ohnuki, Somei

2014-12-01

Transmission electron microscope (TEM) observation of light metal hydrides is complicated by the instability of these materials under electron irradiation. In this study, the electron kinetic energy dependences of the interactions of incident electrons with lithium, sodium and magnesium hydrides, as well as the constituting element effect on the interactions, were theoretically discussed, and electron irradiation damage to these hydrides was examined using in situ TEM. The results indicate that high incident electron kinetic energy helps alleviate the irradiation damage resulting from inelastic or elastic scattering of the incident electrons in the TEM. Therefore, observations and characterizations of these materials would benefit from increased, instead decreased, TEM operating voltage. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Sustainable Management of Electronics

Science.gov (United States)

To provide information on EPAs strategy for electronics stewardship, certified electronics recyclers and the Challenge; as well as where to donate unwanted electronics, how to calculate benefits, and what's going on with electronics mgmt in their states.

Electron acoustic solitary waves in a magnetized plasma with nonthermal electrons and an electron beam

Energy Technology Data Exchange (ETDEWEB)

Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai (India); University of the Western Cape, Belville (South Africa); Devanandhan, S., E-mail: devanandhan@gmail.com [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai (India); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Belville (South Africa)

2016-08-15

A theoretical investigation is carried out to study the obliquely propagating electron acoustic solitary waves having nonthermal hot electrons, cold and beam electrons, and ions in a magnetized plasma. We have employed reductive perturbation theory to derive the Korteweg-de-Vries-Zakharov-Kuznetsov (KdV-ZK) equation describing the nonlinear evolution of these waves. The two-dimensional plane wave solution of KdV-ZK equation is analyzed to study the effects of nonthermal and beam electrons on the characteristics of the solitons. Theoretical results predict negative potential solitary structures. We emphasize that the inclusion of finite temperature effects reduces the soliton amplitudes and the width of the solitons increases by an increase in the obliquity of the wave propagation. The numerical analysis is presented for the parameters corresponding to the observations of “burst a” event by Viking satellite on the auroral field lines.

Impulse approximation treatment of electron-electron excitation and ionization in energetic ion-atom collisions

International Nuclear Information System (INIS)

Zouros, T.J.M.; Lee, D.H.; Sanders, J.M.; Richard, P.

1993-01-01

The effect of electron-electron interactions between projectile and target electrons observed in recent measurements of projectile K-shell excitation and ionization using 0 projectile Auger electron spectroscopy are analysed within the framework of the impulse approximation (IA). The IA formulation is seen to give a good account of the threshold behavior of both ionization and excitation, while providing a remarkably simple intuitive picture of such electron-electron interactions in ion-atom collisions in general. Thus, the applicability of the IA treatment is extended to cover most known processes involving such interactions including resonance transfer excitation, binary encounter electron production, electron-electron excitation and ionization. (orig.)

Printed Electronics

Science.gov (United States)

Wade, Jessica; Hollis, Joseph Razzell; Wood, Sebastian

2018-04-01

The combination of printing technology with manufacturing electronic devices enables a new paradigm of printable electronics, where 'smart' functionality can be readily incorporated into almost any product at low cost. Over recent decades, rapid progress has been made in this field, which is now emerging into the industrial andcommercial realm. However, successful development and commercialisation on a large scale presents some significant technical challenges. For fully-printable electronic systems, all the component parts must be deposited from solutions (inks), requiring the development of new inorganic, organic and hybrid materials.A variety of traditional printing techniques are being explored and adapted forprinting these new materials in ways that result in the best performing electronicdevices. Whilst printed electronics research has initially focused on traditional typesof electronic device such as light-emitting diodes, transistors, and photovoltaics, it is increasingly apparent that a much wider range of applications can be realised. The soft and stretchable nature of printable materials makes them perfect candidates forbioelectronics, resulting in a wealth of research looking at biocompatible printable inks and biosensors. Regardless of application, the properties of printed electronicmaterials depend on the chemical structures, processing conditions, device architecture,and operational conditions, the complex inter-relationships of which aredriving ongoing research. We focus on three particular 'hot topics', where attention is currently focused: novel materials, characterisation techniques, and device stability. With progress advancing very rapidly, printed electronics is expected to grow over the next decade into a key technology with an enormous economic and social impact.

Engineered phages for electronics.

Science.gov (United States)

Cui, Yue

2016-11-15

Phages are traditionally widely studied in biology and chemistry. In recent years, engineered phages have attracted significant attentions for functionalization or construction of electronic devices, due to their specific binding, catalytic, nucleating or electronic properties. To apply the engineered phages in electronics, these are a number of interesting questions: how to engineer phages for electronics? How are the engineered phages characterized? How to assemble materials with engineered phages? How are the engineered phages micro or nanopatterned? What are the strategies to construct electronics devices with engineered phages? This review will highlight the early attempts to address these questions and explore the fundamental and practical aspects of engineered phages in electronics, including the approaches for selection or expression of specific peptides on phage coat proteins, characterization of engineered phages in electronics, assembly of electronic materials, patterning of engineered phages, and construction of electronic devices. It provides the methodologies and opens up ex-cit-ing op-por-tu-ni-ties for the development of a variety of new electronic materials and devices based on engineered phages for future applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Electron-electron interactions in graphene field-induced quantum dots in a high magnetic field

DEFF Research Database (Denmark)

Orlof, A.; Shylau, Artsem; Zozoulenko, I. V.

2015-01-01

We study the effect of electron-electron interaction in graphene quantum dots defined by an external electrostatic potential and a high magnetic field. To account for the electron-electron interaction, we use the Thomas-Fermi approximation and find that electron screening causes the formation...... of compressible strips in the potential profile and the electron density. We numerically solve the Dirac equations describing the electron dynamics in quantum dots, and we demonstrate that compressible strips lead to the appearance of plateaus in the electron energies as a function of the magnetic field. Finally...

Tunable Electron-Electron Interactions in LaAlO_{3}/SrTiO_{3} Nanostructures

Directory of Open Access Journals (Sweden)

Guanglei Cheng

2016-12-01

Full Text Available The interface between the two complex oxides LaAlO_{3} and SrTiO_{3} has remarkable properties that can be locally reconfigured between conducting and insulating states using a conductive atomic force microscope. Prior investigations of “sketched” quantum dot devices revealed a phase in which electrons form pairs, implying a strongly attractive electron-electron interaction. Here, we show that these devices with strong electron-electron interactions can exhibit a gate-tunable transition from a pair-tunneling regime to a single-electron (Andreev bound state tunneling regime where the interactions become repulsive. The electron-electron interaction sign change is associated with a Lifshitz transition where the d_{xz} and d_{yz} bands start to become occupied. This electronically tunable electron-electron interaction, combined with the nanoscale reconfigurability of this system, provides an interesting starting point towards solid-state quantum simulation.

Polymer electronics

CERN Document Server

Geoghegan, Mark

2013-01-01

Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

Electron optics

CERN Document Server

Grivet, Pierre; Bertein, F; Castaing, R; Gauzit, M; Septier, Albert L

1972-01-01

Electron Optics, Second English Edition, Part I: Optics is a 10-chapter book that begins by elucidating the fundamental features and basic techniques of electron optics, as well as the distribution of potential and field in electrostatic lenses. This book then explains the field distribution in magnetic lenses; the optical properties of electrostatic and magnetic lenses; and the similarities and differences between glass optics and electron optics. Subsequent chapters focus on lens defects; some electrostatic lenses and triode guns; and magnetic lens models. The strong focusing lenses and pris

Development of a secondary electron energy analyzer for a transmission electron microscope.

Science.gov (United States)

Magara, Hideyuki; Tomita, Takeshi; Kondo, Yukihito; Sato, Takafumi; Akase, Zentaro; Shindo, Daisuke

2018-04-01

A secondary electron (SE) energy analyzer was developed for a transmission electron microscope. The analyzer comprises a microchannel plate (MCP) for detecting electrons, a coil for collecting SEs emitted from the specimen, a tube for reducing the number of backscattered electrons incident on the MCP, and a retarding mesh for selecting the energy of SEs incident on the MCP. The detection of the SEs associated with charging phenomena around a charged specimen was attempted by performing electron holography and SE spectroscopy using the energy analyzer. The results suggest that it is possible to obtain the energy spectra of SEs using the analyzer and the charging states of a specimen by electron holography simultaneously.

Anatomical, biochemical, and photosynthetic responses to recent allopolyploidy in Glycine dolichocarpa (Fabaceae).

Science.gov (United States)

Coate, Jeremy E; Luciano, Amelia K; Seralathan, Vasu; Minchew, Kevin J; Owens, Tom G; Doyle, Jeff J

2012-01-01

Previous studies have shown that polyploidy has pronounced effects on photosynthesis. Most of these studies have focused on synthetic or recently formed autopolyploids, and comparatively little is known about the integrated effects of natural allopolyploidy, which involves hybridity and genome doubling and often incorporates multiple genotypes through recurrent origins and lineage recombination. Glycine dolichocarpa (designated T2) is a natural allotetraploid with multiple origins. We quantified 21 anatomical, biochemical, and physiological phenotypes relating to photosynthesis in T2 and its diploid progenitors, G. tomentella (D3) and G. syndetika (D4). To assess how direction of cross affects these phenotypes, we included three T2 accessions having D3-like plastids (T2(D3)) and two accessions having D4-like plastids (T2(D4)). T2 accessions were transgressive (more extreme than any diploid accession) for 17 of 21 phenotypes, and species means differed significantly in T2 vs. both progenitors for four of 21 phenotypes (higher for guard cell length, electron transport capacity [J(max)] per palisade cell, and J(max) per mesophyll cell; lower for palisade cells per unit leaf area). Within T2, four of 21 parameters differed significantly between T2(D3) and T2(D4) (palisade cell volume; chloroplast number and volume per unit leaf area; and J(max) per unit leaf area). T2 is characterized by transgressive photosynthesis-related phenotypes (including an ca. 2-fold increase in J(max) per cell), as well as by significant intraspecies variation correlating with plastid type. These data indicate prominent roles for both nucleotypic effects and cytoplasmic factors in photosynthetic responses to allopolyploidy.

Electron beam welding

International Nuclear Information System (INIS)

Schwartz, M.M.

1974-01-01

Electron-beam equipment is considered along with fixed and mobile electron-beam guns, questions of weld environment, medium and nonvacuum welding, weld-joint designs, tooling, the economics of electron-beam job shops, aspects of safety, quality assurance, and repair. The application of the process in the case of individual materials is discussed, giving attention to aluminum, beryllium, copper, niobium, magnesium, molybdenum, tantalum, titanium, metal alloys, superalloys, and various types of steel. Mechanical-property test results are examined along with the areas of application of electron-beam welding

Electronic signal conditioning

CERN Document Server

NEWBY, BRUCE

1994-01-01

At technician level, brief references to signal conditioning crop up in a fragmented way in various textbooks, but there has been no single textbook, until now!More advanced texts do exist but they are more mathematical and presuppose a higher level of understanding of electronics and statistics. Electronic Signal Conditioning is designed for HNC/D students and City & Guilds Electronics Servicing 2240 Parts 2 & 3. It will also be useful for BTEC National, Advanced GNVQ, A-level electronics and introductory courses at degree level.

Vibrational and electronic excitation of hexatriacontane thin films by low energy electron impact

International Nuclear Information System (INIS)

Vilar, M.R.; Schott, M.; Pfluger, P.

1990-01-01

Thin polycrystalline films of hexatriacontane (HTC) were irradiated with low energy (E=0.5--15 eV) electrons, and off-specular backscattered electron spectra were measured. Below E∼7 eV, single and multiple vibrational excitations only are observed, which relax the electrons down to the bottom of the HTC conduction band. Due to the negative electron affinity of HTC, thermal electrons are emitted into vacuum. Structure in the backscattered electron current at kinetic energies about 1.5 and 4 eV are associated to conduction band density of states. Above E∼7 eV, the dominant losses correspond to electronic excitations, excitons, or above a threshold (energy of the electron inside the HTC film) at 9.2±0.1 eV, electron--hole pair generation. The latter process is very efficient and reaches a yield of the order of one ∼11 eV. Evidence for chemical reaction above E∼4 eV is observed

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African Journals Online (AJOL)

WAKAWA LUCKY

The family Fabaceae recorded the highest frequency and percentage frequency of 11 ... domestic energy use in Nigeria was reported to come from wood ..... inventory of indigenous tree species within. Dutsin-Ma area in ... Self-Assessment for.

Evaluation of phytoremediation potential of Peltophorum pterocarpum

African Journals Online (AJOL)

ADOWIE PERE

De Wit., and Crotolaria retusa Linn) of Fabaceae plant family in relation to ... the species treated soils showed that in pre-polluted soil foliar enzyme ..... also promoted enzyme activation or inducible enzymes .... coal-conversion waste waters.

Tshikalange et al., Afr J Tradit Complement Altern Med. (2016) 13(6 ...

African Journals Online (AJOL)

importance and urgent so that it can be preserved and conserved (Maroyi, 2012). Traditional knowledge is ... Stem. Infusion. Diarrhoea. 1. 11 0.70. Acacia nilotica. Fabaceae. Mugamazu. Mophutin ... Decoction. Fertility in women 2. 10 0.67.

Characterisation of 100 kW electron beam melting gun and its adaptation as electron gun for high power DC electron accelerators

International Nuclear Information System (INIS)

Banerjee, Srutarshi; Bhattacharjee, Dhruva; Waghmare, Abhay; Tiwari, Rajnish; Bakhtsingh, R.I.; Dasgupta, K.; Gupta, Sachin; Prakash, Baibhaw; Jha, M.N.

2015-01-01

The paper deals with the characterization of the 100 kW electron beam melting gun for its adaptation in high power DC Electron Accelerators. The indigenously designed electron beam melting system at BARC is chosen for characterization. It comprises of electron gun as source of electrons, two electromagnetic focusing lenses viz. upper focusing lens and lower focusing lens for beam focusing, intermediate beam aperture for vacuum decoupling between gun region and melt zone, deflection and oscillation lens for maneuvering the beam on the melt charge and water cooled crucible that acts as a beam dump. In this system, the electron gun is designed for 40 kV and 100 kW corresponding to a maximum beam current of 2.5 A. The electron gun uses directly heated spiral tungsten filament. The operating temperature of the filament is 2800 °K. The focusing electrode and the anode profile are designed based on Pierce geometry. High Power DC Electron Accelerators require high currents of 1 A. The beam must comply with the requirement of 40 mm beam diameter and 10 mrad divergence at the exit of the electron gun. The characterization of the existing electron gun was done to find out all the beam parameters, for e.g. beam size, beam divergence, perveance etc. to be adapted or to be modified for the design of electron gun for high power DC accelerators. This paper shows limitations and the possible solutions for design of high power DC accelerators. (author)

Organic High Electron Mobility Transistors Realized by 2D Electron Gas.

Science.gov (United States)

Zhang, Panlong; Wang, Haibo; Yan, Donghang

2017-09-01

A key breakthrough in inorganic modern electronics is the energy-band engineering that plays important role to improve device performance or develop novel functional devices. A typical application is high electron mobility transistors (HEMTs), which utilizes 2D electron gas (2DEG) as transport channel and exhibits very high electron mobility over traditional field-effect transistors (FETs). Recently, organic electronics have made very rapid progress and the band transport model is demonstrated to be more suitable for explaining carrier behavior in high-mobility crystalline organic materials. Therefore, there emerges a chance for applying energy-band engineering in organic semiconductors to tailor their optoelectronic properties. Here, the idea of energy-band engineering is introduced and a novel device configuration is constructed, i.e., using quantum well structures as active layers in organic FETs, to realize organic 2DEG. Under the control of gate voltage, electron carriers are accumulated and confined at quantized energy levels, and show efficient 2D transport. The electron mobility is up to 10 cm 2 V -1 s -1 , and the operation mechanisms of organic HEMTs are also argued. Our results demonstrate the validity of tailoring optoelectronic properties of organic semiconductors by energy-band engineering, offering a promising way for the step forward of organic electronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Downshift of electron plasma oscillations in the electron foreshock region

International Nuclear Information System (INIS)

Fuselier, S.A.

1984-01-01

Electron plasma oscillations in the Earth's electron foreshock region are observed to shift above and below the local electron plasma frequency. As plasma oscillations shift from the plasma frequency, their bandwidth increases and their wavelength decreases. Observations of plasma oscillations well below the plasma frequency are correlated with times when ISEE-I is far downstream of the electron foreshock boundary. Although wavelengths of plasma oscillations below the plasma frequency satisfy klambda/sub De/ approx. = 1, the Doppler shift due to the motion of the solar wind is not sufficient to produce the observed frequency shifts. A beam-plasma interaction with beam velocities on the order of the electron thermal velocity is suggested as an explanation for plasma oscillations above and below the plasma frequency. Frequency, bandwidth, and wavelength changes predicted from the beam-plasma interaction are in good agreement with the observed characteristics of plasma oscillations in the foreshock region

MIS hot electron devices for enhancement of surface reactivity by hot electrons

DEFF Research Database (Denmark)

Thomsen, Lasse Bjørchmar

A Metal-Insulator-Semiconductor (MIS) based device is developed for investigation of hot electron enhanced chemistry. A model of the device is presented explaining the key concepts of the functionality and the character- istics. The MIS hot electron emitter is fabricated using cleanroom technology...... and the process sequence is described. An Ultra High Vacuum (UHV) setup is modified to facilitate experiments with electron emission from the MIS hot electron emitters and hot electron chemistry. Simulations show the importance of keeping tunnel barrier roughness to an absolute minimum. The tunnel oxide...... to be an important energy loss center for the electrons tunneling through the oxide lowering the emission e±ciency of a factor of 10 for a 1 nm Ti layer thickness. Electron emission is observed under ambient pressure conditions and in up to 2 bars of Ar. 2 bar Ar decrease the emission current by an order...

EFFECTIVE ELECTRONIC TUTORIAL

Directory of Open Access Journals (Sweden)

Andrei A. Fedoseev

2014-01-01

Full Text Available The article analyzes effective electronic tutorials creation and application based on the theory of pedagogy. Herewith the issues of necessary electronic tutorial functional, ways of the educational process organization with the use of information and communication technologies and the logistics of electronic educational resources are touched upon. 

Theoretical investigations of molecular wires: Electronic spectra and electron transport

Science.gov (United States)

Palma, Julio Leopoldo

The results of theoretical and computational research are presented for two promising molecular wires, the Nanostar dendrimer, and a series of substituted azobenzene derivatives connected to aluminum electrodes. The electronic absorption spectra of the Nanostar (a phenylene-ethynylene dendrimer attached to an ethynylperylene chromophore) were calculated using a sequential Molecular Dynamics/Quantum Mechanics (MD/QM) method to perform an analysis of the temperature dependence of the electronic absorption process. We modeled the Nanostar as a series of connected units, and performed MD simulations for each chromophore at 10 K and 300 K to study how the temperature affected the structures and, consequently, the spectra. The absorption spectra of the Nanostar were computed using an ensemble of 8000 structures for each chromophore. Quantum Mechanical (QM) ZINDO/S calculations were performed for each conformation in the ensemble, including 16 excited states, for a total of 128,000 excitation energies. The spectral intensity was then scaled linearly with the number of conjugated units. Our calculations for both the individual chromophores and the Nanostar, are in good agreement with experiments. We explain in detail the effects of temperature and the consequences for the absorption process. The second part of this thesis presents a study of the effects of chemical substituents on the electron transport properties of the azobenzene molecule, which has been proposed recently as a component of a light-driven molecular switch. This molecule has two stable conformations (cis and trans) in its electronic ground state, with considerable differences in their conductance. The electron transport properties were calculated using first-principles methods combining non-equilibrium Green's function (NEGF) techniques with density functional theory (DFT). For the azobenzene studies, we included electron-donating groups and electron-withdrawing groups in meta- and ortho-positions with

Evaluation of high-energy brachytherapy source electronic disequilibrium and dose from emitted electrons.

Science.gov (United States)

Ballester, Facundo; Granero, Domingo; Pérez-Calatayud, José; Melhus, Christopher S; Rivard, Mark J

2009-09-01

The region of electronic disequilibrium near photon-emitting brachytherapy sources of high-energy radionuclides (60Co, 137CS, 192Ir, and 169Yb) and contributions to total dose from emitted electrons were studied using the GEANT4 and PENELOPE Monte Carlo codes. Hypothetical sources with active and capsule materials mimicking those of actual sources but with spherical shape were examined. Dose contributions due to source photons, x rays, and bremsstrahlung; source beta-, Auger electrons, and internal conversion electrons; and water collisional kerma were scored. To determine if conclusions obtained for electronic equilibrium conditions and electron dose contribution to total dose for the representative spherical sources could be applied to actual sources, the 192Ir mHDR-v2 source model (Nucletron B.V., Veenendaal, The Netherlands) was simulated for comparison to spherical source results and to published data. Electronic equilibrium within 1% is reached for 60Co, 137CS, 192Ir, and 169Yb at distances greater than 7, 3.5, 2, and 1 mm from the source center, respectively, in agreement with other published studies. At 1 mm from the source center, the electron contributions to total dose are 1.9% and 9.4% for 60Co and 192Ir, respectively. Electron emissions become important (i.e., > 0.5%) within 3.3 mm of 60Co and 1.7 mm of 192Ir sources, yet are negligible over all distances for 137Cs and 169Yb. Electronic equilibrium conditions along the transversal source axis for the mHDR-v2 source are comparable to those of the spherical sources while electron dose to total dose contribution are quite different. Electronic equilibrium conditions obtained for spherical sources could be generalized to actual sources while electron contribution to total dose depends strongly on source dimensions, material composition, and electron spectra.

Direct single electron detection with a CMOS detector for electron microscopy

International Nuclear Information System (INIS)

Faruqi, A.R.; Henderson, R.; Pryddetch, M.; Allport, P.; Evans, A.

2005-01-01

We report the results of an investigation into the use of a monolithic active pixel sensor (MAPS) for electron microscopy. MAPS, designed originally for astronomers at the Rutherford Appleton Laboratories, was installed in a 120 kV electron microscope (Philips CM12) at the MRC Laboratory in Cambridge for tests which included recording single electrons at 40 and 120 keV, and measuring signal-to-noise ratio (SNR), spatial resolution and radiation sensitivity. Our results show that, due to the excellent SNR and resolution, it is possible to register single electrons. The radiation damage to the detector is apparent with low doses and gets progressively greater so that its lifetime is limited to 600,000-900,000 electrons/pixel (very approximately 10-15 krad). Provided this detector can be radiation hardened to reduce its radiation sensitivity several hundred fold and increased in size, it will provide excellent performance for all types of electron microscopy

Fundamentals of electronics

CERN Document Server

Schubert, Thomas F

2015-01-01

This book, Electronic Devices and Circuit Application, is the first of four books of a larger work, Fundamentals of Electronics. It is comprised of four chapters describing the basic operation of each of the four fundamental building blocks of modern electronics: operational amplifiers, semiconductor diodes, bipolar junction transistors, and field effect transistors. Attention is focused on the reader obtaining a clear understanding of each of the devices when it is operated in equilibrium. Ideas fundamental to the study of electronic circuits are also developed in the book at a basic level to

High-power electronics

CERN Document Server

Kapitsa, Petr Leonidovich

1966-01-01

High-Power Electronics, Volume 2 presents the electronic processes in devices of the magnetron type and electromagnetic oscillations in different systems. This book explores the problems of electronic energetics.Organized into 11 chapters, this volume begins with an overview of the motion of electrons in a flat model of the magnetron, taking into account the in-phase wave and the reverse wave. This text then examines the processes of transmission of electromagnetic waves of various polarization and the wave reflection from grids made of periodically distributed infinite metal conductors. Other

Electron Bifurcation: Thermodynamics and Kinetics of Two-Electron Brokering in Biological Redox Chemistry

Energy Technology Data Exchange (ETDEWEB)

Zhang, Peng; Yuly, Jonathon L.; Lubner, Carolyn E. [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Mulder, David W. [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; King, Paul W. [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Peters, John W. [Institute; Beratan, David N. [Department

2017-08-23

How can proteins drive two electrons from a redox active donor onto two acceptors at very different potentials and distances? And how can this transaction be conducted without dissipating very much energy or violating the laws of thermodynamics? Nature appears to have addressed these challenges by coupling thermodynamically uphill and downhill electron transfer reactions, using two-electron donor cofactors that have very different potentials for the removal of the first and second electron. Although electron bifurcation is carried out with near perfection from the standpoint of energy conservation and electron delivery yields, it is a biological energy transduction paradigm that has only come into focus recently. This Account provides an exegesis of the biophysical principles that underpin electron bifurcation.

Printed Electronics

Science.gov (United States)

Korkut, Sibel (Inventor); Chiang, Katherine S. (Inventor); Crain, John M. (Inventor); Aksay, Ilhan A. (Inventor); Lettow, John S. (Inventor); Chen, Chuan-Hua (Inventor); Prud'Homme, Robert K. (Inventor)

2018-01-01

Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

Production of accelerated electrons near an electron source in the plasma resonance region

International Nuclear Information System (INIS)

Fedorov, V.A.

1989-01-01

Conditions of generation of plasma electrons accelerated and their characteristics in the vicinity of an electron source are determined. The electron source isolated electrically with infinitely conducting surface, being in unrestricted collisionless plasma ω 0 >>ν, where ω 0 - plasma frequency of nonperturbated plasma, ν - frequency of plasma electron collisions with other plasma particles, is considered. Spherically symmetric injection of electrons, which rates are simulated by ω frequency, occurs from the source surface. When describing phenomena in the vicinity of the electron source, one proceeds from the quasihydrodynamic equation set

A superconducting electron spectrometer

International Nuclear Information System (INIS)

Guttormsen, M.; Huebel, H.; Grumbkow, A. von

1983-03-01

The set-up and tests of an electron spectrometer for in-beam conversion electron measurements are described. A superconducting solenoid is used to transport the electrons from the target to cooled Si(Li) detectors. The solenoid is designed to produce either a homogeneous axially symmetric field of up to 2 Tesla or a variety of field profiles by powering the inner and outer set of coils of the solenoid separately. The electron trajectories resulting for various field profiles are discussed. In-beam electron spectra taken in coincidence with electrons, gammas and alpha-particles are shown. (Auth.)

Electron-electron interaction in Multiple Quantum Wells

Science.gov (United States)

Zybert, M.; Marchewka, M.; Tomaka, G.; Sheregii, E. M.

2012-07-01

The complex investigation of the magneto-transport effects in structures containing multiple quantum well (MQWs) based on the GaAs/AlGaAs-heterostructures has been performed. The MQWs investigated have different electron densities in QWs. The parameters of 2DEG in MQWs were determined from the data of the Integer Quantum Hall Effect (IQHE) and Shubnikov-de Haas oscillations (SdH) observed at low temperatures (0.6-4.2 K). The method of calculation of the electron states energies in MQWs has been developed which is based on the splitting of these states due to the exchange interaction (SAS-splitting, see D. Płoch et al., Phys. Rev. B 79 (2009) 195434) including the screening of this interaction. The IQHE and SdH observed in these multilayer structures with the third degree of freedom for electrons are interpreted from this.

Electronic plants

Science.gov (United States)

Stavrinidou, Eleni; Gabrielsson, Roger; Gomez, Eliot; Crispin, Xavier; Nilsson, Ove; Simon, Daniel T.; Berggren, Magnus

2015-01-01

The roots, stems, leaves, and vascular circuitry of higher plants are responsible for conveying the chemical signals that regulate growth and functions. From a certain perspective, these features are analogous to the contacts, interconnections, devices, and wires of discrete and integrated electronic circuits. Although many attempts have been made to augment plant function with electroactive materials, plants’ “circuitry” has never been directly merged with electronics. We report analog and digital organic electronic circuits and devices manufactured in living plants. The four key components of a circuit have been achieved using the xylem, leaves, veins, and signals of the plant as the template and integral part of the circuit elements and functions. With integrated and distributed electronics in plants, one can envisage a range of applications including precision recording and regulation of physiology, energy harvesting from photosynthesis, and alternatives to genetic modification for plant optimization. PMID:26702448

Radially localized measurements of superthermal electrons using oblique electron cyclotron emission

International Nuclear Information System (INIS)

Preische, S.; Efthimion, P.C.; Kaye, S.M.

1996-05-01

It is shown that radial localization of optically tin Electron Cyclotron Emission from superthermal electrons can be imposed by observation of emission upshifted from the thermal cyclotron resonance in the horizontal midplane of a tokamak. A new and unique diagnostic has been proposed and operated to make radially localized measurements of superthermal electrons during Lower Hybrid Current Drive on the PBX-M tokamak. The superthermal electron density profile as well as moments of the electron energy distribution as a function of radius are measured during Lower Hybrid Current Drive. The time evolution of these measurements after the Lower Hybrid power is turned off are given and the observed behavior reflects the collisional isotropization of the energy distribution and radial diffusion of the spatial profile

Practical microwave electron devices

CERN Document Server

Meurant, Gerard

2013-01-01

Practical Microwave Electron Devices provides an understanding of microwave electron devices and their applications. All areas of microwave electron devices are covered. These include microwave solid-state devices, including popular microwave transistors and both passive and active diodes; quantum electron devices; thermionic devices (including relativistic thermionic devices); and ferrimagnetic electron devices. The design of each of these devices is discussed as well as their applications, including oscillation, amplification, switching, modulation, demodulation, and parametric interactions.

Neutrinos in the Electron

International Nuclear Information System (INIS)

Koschmieder, E. L.

2007-01-01

I will show that one half of the rest mass of the electron consists of electron neutrinos and that the other half of the rest mass of the electron consists of the mass in the energy of electric oscillations. With this composition we can explain the rest mass of the electron, its charge, its spin and its magnetic moment We have also determined the rest masses of the muon neutrino and the electron neutrino

Downshift of electron plasma oscillations in the electron foreshock region

International Nuclear Information System (INIS)

Fuselier, S.A.; Gurnett, D.A.; Fitzenreiter, R.J.; NASA, Goddard Space Flight Center, Greenbelt, MD)

1985-01-01

Electron plasma oscillations in the earth's electron foreshock region are observed to shift above and below the local electron plasma frequency. As plasma oscillations shift downward from the plasma frequency, their bandwidth increases and their wavelength decreases. Observations of plasma oscillations well below the plasma frequency are correlated with times when ISEE 1 is far downstream of the electron foreshock boundary. Although wavelengths of plasma oscillations below the plasma frequency satisfy k x lambda-De approximately 1 the Doppler shift due to the motion of the solar wind is not sufficient to produce the observed frequency shifts. A beam-plasma interaction with beam velocities on the order of the electron thermal velocity is suggested as an explanation for plasma oscillations above and below the plasma frequency. Frequency, bandwidth, and wavelength changes predicted from the beam-plasma interaction are in good agreement with the observed characteristics of plasma oscillations in the foreshock region. 28 references

Paleoclassical electron heat transport

International Nuclear Information System (INIS)

Callen, J.D.

2005-01-01

Radial electron heat transport in low collisionality, magnetically-confined toroidal plasmas is shown to result from paleoclassical Coulomb collision processes (parallel electron heat conduction and magnetic field diffusion). In such plasmas the electron temperature equilibrates along magnetic field lines a long length L, which is the minimum of the electron collision length and a maximum effective half length of helical field lines. Thus, the diffusing field lines induce a radial electron heat diffusivity M ≅ L/(πR 0q ) ∼ 10 >> 1 times the magnetic field diffusivity η/μ 0 ≅ ν e (c/ω p ) 2 . The paleoclassical electron heat flux model provides interpretations for many features of 'anomalous' electron heat transport: magnitude and radial profile of electron heat diffusivity (in tokamaks, STs, and RFPs), Alcator scaling in high density plasmas, transport barriers around low order rational surfaces and near a separatrix, and a natural heat pinch (or minimum temperature gradient) heat flux form. (author)

Surface characterization by energy distribution measurements of secondary electrons and of ion-induced electrons

International Nuclear Information System (INIS)

Bauer, H.E.; Seiler, H.

1988-01-01

Instruments for surface microanalysis (e.g. scanning electron or ion microprobes, emission electron or ion microscopes) use the current of emitted secondary electrons or of emitted ion-induced electrons for imaging of the analysed surface. These currents, integrating over all energies of the emitted low energy electrons, are however, not well suited to surface analytical purposes. On the contrary, the energy distribution of these electrons is extremely surface-sensitive with respect to shape, size, width, most probable energy, and cut-off energy. The energy distribution measurements were performed with a cylindrical mirror analyser and converted into N(E), if necessary. Presented are energy spectra of electrons released by electrons and argon ions of some contaminated and sputter cleaned metals, the change of the secondary electron energy distribution from oxidized aluminium to clean aluminium, and the change of the cut-off energy due to work function change of oxidized aluminium, and of a silver layer on a platinum sample. The energy distribution of the secondary electrons often shows detailed structures, probably due to low-energy Auger electrons, and is broader than the energy distribution of ion-induced electrons of the same object point. (author)

Electron transfer by excited benzoquinone anions: slow rates for two-electron transitions.

Science.gov (United States)

Zamadar, Matibur; Cook, Andrew R; Lewandowska-Andralojc, Anna; Holroyd, Richard; Jiang, Yan; Bikalis, Jin; Miller, John R

2013-09-05

Electron transfer (ET) rate constants from the lowest excited state of the radical anion of benzoquinone, BQ(-•)*, were measured in THF solution. Rate constants for bimolecular electron transfer reactions typically reach the diffusion-controlled limit when the free-energy change, ΔG°, reaches -0.3 eV. The rate constants for ET from BQ(-•)* are one-to-two decades smaller at this energy and do not reach the diffusion-controlled limit until -ΔG° is 1.5-2.0 eV. The rates are so slow probably because a second electron must also undergo a transition to make use of the energy of the excited state. Similarly, ET, from solvated electrons to neutral BQ to form the lowest excited state, is slow, while fast ET is observed at a higher excited state, which can be populated in a transition involving only one electron. A simple picture based on perturbation theory can roughly account for the control of electron transfer by the need for transition of a second electron. The picture also explains how extra driving force (-ΔG°) can restore fast rates of electron transfer.

Rapid low dose electron tomography using a direct electron detection camera

NARCIS (Netherlands)

V. Migunov (Vadim); H. Ryll; X. Zhuge (Jason); M. Simson; L. Strüder; K.J. Batenburg (Joost); L. Houben; R.E. Dunin-Borkowski (Rafal)

2015-01-01

htmlabstractWe demonstrate the ability to record a tomographic tilt series containing 3487 images in only 3.5 s by using a direct electron detector in a transmission electron microscope. The electron dose is lower by at least one order of magnitude when compared with that used to record a

High-intensity-laser-electron scattering

International Nuclear Information System (INIS)

Meyerhofer, D.D.

1997-01-01

In the field of an intense laser, photon-electron scattering becomes nonlinear when the oscillatory energy of the electron approaches its rest mass. The electron wave function is dressed by the field with a concomitant increase in the effective electron mass. When the photon energy in the electron rest frame is comparable to the electron rest mass, multiphoton Compton scattering occurs. When the photon energy is significantly lower than the electron rest mass, the electron acquires momentum from the photon field and emits harmonics. This paper reviews nonlinear photon-electron scattering processes and results from two recent experiments where they have been observed

Automotive electronics design fundamentals

CERN Document Server

Zaman, Najamuz

2015-01-01

This book explains the topology behind automotive electronics architectures and examines how they can be profoundly augmented with embedded controllers. These controllers serve as the core building blocks of today’s vehicle electronics. Rather than simply teaching electrical basics, this unique resource focuses on the fundamental concepts of vehicle electronics architecture, and details the wide variety of Electronic Control Modules (ECMs) that enable the increasingly sophisticated "bells & whistles" of modern designs.  A must-have for automotive design engineers, technicians working in automotive electronics repair centers and students taking automotive electronics courses, this guide bridges the gap between academic instruction and industry practice with clear, concise advice on how to design and optimize automotive electronics with embedded controllers.

Efecto de las arañas (Arachnida: Araneae como depredadoras de insectos plaga en cultivos de alfalfa (Medicago sativa (Fabaceae en Argentina

Directory of Open Access Journals (Sweden)

Andrea Armendano

2011-12-01

Full Text Available Effect of spiders (Arachnida: Araneae as predators of insect pest in alfalfa crops (Medicago sativa (Fabaceae in Argentina. Spiders are predators that reduce insect pest populations in agroecosystems. Trials were conducted to measure the selectivity against different insect preys, the daily consumption, effect of predators alone and together with a known number of preys, and the indirect effect of predators on vegetation. For this, experimental units (1x1m were used covered with a fine plastic mesh. Misumenops pallidus, Oxyopes salticus and Araneus sp. were used as generalist predators, and aphids, weevils, locusts, chrysomelids and Lepidoptera larvae as their potential preys. Among the preys offered, the spiders preferred Lepidoptera larvae compared to the other two pests groups (weevils and aphids. The maximum consumption rate was of 93.33% for Lepidoptera larvae, 25.33% for aphids and 11.67% for weevils. The Q Index values for the three species of spiders showed a positive selectivity only for defoliating larvae. O. salticus showed the highest values of consumption rates while Rachiplusia nu was the most consumed. The maximum value of consumption in 24 hours was showed by O. salticus on R. nu (C=2.8. The association of several species of predatory spiders increased the total number of insects captured, and also showed that the addition of spiders caused a decrease in the number of leaves damaged by the effect of lepidopterous larvae. Rev. Biol. Trop. 59 (4: 1651-1662. Epub 2011 December 01Las arañas son depredadoras capaces de reducir las poblaciones de insectos plaga en agroecosistemas. Para medir la selectividad frente a distintas presas, se realizaron ensayos de consumo diario, efecto de los depredadores aisladamente y en conjunto sobre el número de presas y efecto indirecto de los depredadores sobre la vegetación; se utilizaron jaulas experimentales de 1x1m cubiertas con una fina malla plástica. Misumenops pallidus, Oxyopes salticus y

Electronic diagrams

CERN Document Server

Colwell, Morris A

1976-01-01

Electronic Diagrams is a ready reference and general guide to systems and circuit planning and in the preparation of diagrams for both newcomers and the more experienced. This book presents guidelines and logical procedures that the reader can follow and then be equipped to tackle large complex diagrams by recognition of characteristic 'building blocks' or 'black boxes'. The goal is to break down many of the barriers that often seem to deter students and laymen in learning the art of electronics, especially when they take up electronics as a spare time occupation. This text is comprised of nin