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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical crystallography 30 (2000), S. 219-222 
    ISSN: 1572-8854
    Keywords: Aluminum ; alkoxide ; five-coordinate ; six-coordinate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The present contribution will demonstrate that monomeric alkoxide compounds can be formed by the use of the Salen(tBu) ligand. These alkoxides, LAlOR (with L=Salen (tBu), R=Me (1), Salomphen(tBu), R=Me (3) and L=Salen(tBu), R=Et (4)) feature five-coordinate monomeric aluminum (Salen(tBu)=N,N′-ethylenebis(3,5-di-tert-butylsalicylideneimine) and Salomphen(tBu)=N,N′-(4,5-di-methyl)phenylenenebis(3,5-di-tert-butylsalicylideneimine). Crystallization of 1 from MeOH affords the six-coordinate complex, Salen(tBu)AlOMe(MeOH) (2). The manner in which these compounds may be obtained, as well as the structures of 2 and 4 will be described
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical crystallography 30 (2000), S. 215-218 
    ISSN: 1572-8854
    Keywords: Aluminum ; cation ; Lewis acid ; six-coordinate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The chiral five-coordinate halide compound, Salcen(tBu)AlCl (1) (Salcen = N,N′-cyclohexylenebis(3, 5-di-tert-butylsalicylideneimine) can be used in a salt elimination reaction to produce [R,R'Salcen(tBu)AlOTs] (2) as well as the chiral cationic complex, [R,R'Salcen (tBu)Al(thf)2]+ BPh4 − (3). The conditions under which these types of neutral and cationic complexes form will be discussed. This should provide guidance for the eventual use of the cations as strongly Lewis acidic catalysts and organic synthetic reagents.
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  • 3
    ISSN: 1573-4994
    Keywords: Resting membrane potential ; tetramethylrhodamine methyl ester ; confocal microscopy ; neuroblastoma ; N1E-115
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Digital imaging (confocal microscopy) and a slow potentiometric dye (tetramethylrhodamine methyl ester) were used to assess the resting membrane potential (V m) of murine neuroblastoma cells (N1E-115). The averageV m was found to be −64.0±2.0 mV. The difference between this and the previously reported higher values was attributed to the use of glass microelectrode techniques that probably caused mechanical injury to the cell membranes: Digital imaging of N1E-115V m was found to be sensitive, reproducible, fast, and simple.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant foods for human nutrition 37 (1987), S. 299-306 
    ISSN: 1573-9104
    Keywords: chickpea ; chemical composition ; nutritive value
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Chemical composition and protein quality of the main chickpea varieties cultivated in Mexico were determined. The raw and cooked chickpeas analyzed were: Surutato, Surutato 77, Sonora, Sonora 80, Porquero, Macarena, Breve Duro and a mixture of broken seeds used mainly for animal feeding. The chemical composition of the raw chickpea studied was very similar; the average values of the nutrients were: ash 3.1±0.2, fat 5.0±1.0, protein 19.5±1.2 and fiber 3.7±2.1. Cooking diminished only the ash content and the Porquero variety was the only one that had a high content of crude fiber (9.1%). There was not found agglutinating activity to rabbit RBC in any of the raw chickpeas studied and the trypsin inhibitor activity average was 11.8±2.4 TUI/mg sample. Cooking destroyed 57% of this activity. Digestibility was the same in the raw and in the cooked chickpea (78%). There were not found significant differences in the PER values of the raw and cooked seeds: 1.65–2.30 and 1.80 to 2.61 respectively. The Surutato and Breve Duro varieties were statistically similar to the casein PER (2.5). It could be recommended to use these two varieties mainly for infant feeding.
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  • 5
    ISSN: 0044-2313
    Keywords: Stibocanes ; conformational analysis ; x-ray structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Beziehung zwischen starker transannularer sekundärer Bindung und Konformation in Diphenyldithiophosphinatstibocanen X(CH2CH2S)2SbS2PPh2 (X = O, S)Die beiden Stibocane 1-Oxa-4,6-dithia-5-stibocan-diphenyldithiophosphinat O(CH2CH2S)2SbS2PPh2 1 und 1,3,6-Trithia-2-stibocan-diphenyldithiophosphinat S(CH2CH2S)2SbS2PPh2 2 wurden aus den entsprechenden Chloro-oxa- und -thia-stibocanen 3 und 6 sowie dem Ammoniumsalz der Diphenyldithiophosphinsäure in CH2Cl2 dargestellt. 1 und 2 wurden durch IR, EI-MS und Multikern-NMR-(1H, 13C, 31P{1H}) Spektren charakterisiert. Die Kristallstruktur von 1 zeigt zwei Sb1 ⃛ S1 intermolekulare Wechselwirkungen [3.987(2) Å] so daß sich ein dimeres Molekül ergibt sowie eine endocyclische, transannulare Sb1 ⃛ O1 [2.555(6) Å] und eine exocyclische Sb1 ⃛ S4 sekundäre Wechselwirkung [3.327(2) Å]. Die Koordination am Antimon kann als AX4YE ψ-trigonal bipyramidale Geometrie beschrieben werden, mit A = Sb, X = S1, S2, S3, O1; Y = S4. S1, S2 und das freie Elektronenpaar liegen in der äquatorialen Ebene, O1 und S3 besetzen die axialen Positionen. Die sekundäre Bindung Sb1 ⃛ S4 liegt über einer Ebene, die von dem freien Elektronenpaar der trigonalen Bipyramide, S2 und S3 gebildet wird. Molekül 2 zeigt ebenfalls eine endocyclische, transannulare Sb1 ⃛ S2 [2.949(3) Å] und eine exocyclische Sb1 ⃛ S5 sekundäre Wechselwirkung [3.216(3) Å]. Antimon ist hier ebenfalls fünffach koordiniert, wodurch sich eine AX4YE ψ-trigonale bipyramidale Geometrie ergibt, mit S1, S3 und dem freien Elektronenpaar in der äquatorialen Ebene und mit S2 und S4 in den axialen Positionen. Die sekundäre Bindung Sb1 ⃛ S5 liegt auch hier über einer Ebene, die von dem freien Elektronenpaar der trigonalen Bipyramide, S3 und S4 gebildet wird.
    Notes: The two stibocanes 1-oxa-4,6-dithia-5-stibocane diphenyldithiophosphinate O(CH2CH2S)2SbS2PPh2 1 and 1,3,6-trithia-2-stibocane diphenyldithiophosphinate S(CH2CH2S)2 · SbS2PPh2 2 were prepared from the corresponding chloro oxa- and thia-stibocanes 3 and 6, and the ammonium salt of diphenyldithiophosphinic acid in CH2Cl2. 1 and 2 were characterized by IR, EI-MS and multinuclear NMR (1H, 13C, 31P{1H}). The crystalline state of 1 features two Sb1 ⃛ S1 intermolecular interactions [3.987(2) Å] that results in a dimer. Alongside 1 displays both an endocyclic, transannular Sb1 ⃛ O1 interaction [2.555(6) Å] and an exocyclic Sb1 ⃛ S4 secondary interaction [3.327(2) Å]. The coordination geometry at the antimony could be described as AX4YE ψ-trigonal bipyramid geometry with A = Sb, X = S1, S2, S3,O1; Y = S4; S1, S2 and the lone pair lays on the equatorial plane with O1 and S4 in axial positions. The Sb1 ⃛ S4 secondary bonding is face capping one of the planes form by the lone pair, S2 and S3 of the trigonal bipyramid. 2 also displays both an endocyclic, transannular Sb1 ⃛ S2 interaction [2.949(3) Å] and an exocyclic Sb1 ⃛ S5 secondary interaction [3.216(3) Å]. The antimony becomes five-coordinate, giving the AX4YE ψ-trigonal bipyramid geometry with S1, S3 and the lone pair laying on the equatorial plane with S2 and S4 in axial positions. The Sb1 ⃛ S5 also here is face capping the plane form by the lone pair, S3 and S4 of the trigonal bipyramid.The conformation of the eight membered ring in 2 is boat-chair. In 1 the main conformation is chair-planar.Die Konformation des Achtringes in 2 ist Wanne-Sessel. In 1 ist die Konformation des Achtringes Sessel-planar.
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  • 6
    ISSN: 0044-2313
    Keywords: Stibocanes ; dithiophosphinates ; conformational analysis ; x-ray structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Konformative Trends und intermolekulare Assoziation in Dialkyldithiophosphinat-Stibocanen X(CH2CH2S)2SbS2PR2 (X = O, S; R = Me, Et)Alkylstibocanes O/S(CH2CH2S) 2SbS2PMe2/ Et2 1-4 wurden aus den entsprechenden Chlorooxa- und -thiastibocanen bzw. Natriumdialkyldithiophosphinaten in CH2Cl2 dargestellt und durch IR, EI-MS und Multikern-NMR (1H, 13C, 31P{1H}) charakterisiert. Die Kristall- und Molekülstrukturen von O(CH2CH2S) 2SbS2PMe2 1 und S(CH2CH2S) 2PMe2 3 wurden bestimmt. Die Kristallstruktur von 1 zeigt ein Dimer durch zwei Sb … S-intermolekulare Wechselwirkungen (3,960(3) Å). 3 bildet im kristallinen Zustand eine dimere Struktur durch eine sekundäre Sb … Sb-Bindung (4,067(1) Å), 1 und 3 zeigen endocyclische, transannulare Sb … O/S-Wechselwirkungen (1: 2,561(7) Å; 3: 2,972(1) Å) und exocyclische, sekundäre Sb … S-Bindungen (1: 3,454(2) Å; 3: 3,147(2) Å). Die Strukturen von 1 und 3 können als trigonal bipyramidal beschrieben werden mit zusätzlichen sekundären Kontakten über eine Ebene bzw. Kantenverbrückt. Die Konformation des Achtrings in 3 ist Wanne-Sessel, die in 1 Sessel-planar.
    Notes: The alkyl stibocanes O/S(CH2CH2S)2SbS2PMe2/ Et2 1-4 were prepared from the corresponding chloro oxa and thiastibocanes, and sodium dialkyldithiophosphinates in CH2Cl2. Compounds 1-4 were characterized by IR, EI-MS and multinuclear NMR (1H, 13C, 31P{1H}). The crystal and molecular structures of O(CH2CH2S)2SbS2PMe2 1 and S(CH2CH2S)2SbS2PMe2 3 were determined. The crystalline state of 1 has two Sb … S intermolecular interactions [3.960(3) Å] that results in a dimer. The crystalline state of 3 features a dimeric structure through an Sb … Sb secondary bonding [4.067(1) Å]. Compounds 1 and 3 display both an endocyclic, transannular Sb … O/S interaction [1, 2.561(7) Å; 3 2.972(1) Å] and an exocyclic Sb … S secondary bonding [1, 3.454(2) Å, 3, 3.147(2) Å]. The coordination geometry in 1 and 3 could be described as trigonal bipyramidal with additional secondary bonding contacts face capping or edge bridging the polyhedron. The conformation of the eight membered ring in 3 is boat-chair. Whereas in 1, the mean conformation is chair-planar.
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  • 7
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Acute inflammation was induced in pigs using a single subcutaneous turpentine injection. The acute phase serum protein response was analyzed using crossed immunoelectrophoresis and immunodiffusion. The concentration of C reactive protein and haptoglobin increases 5-7 times 48 h after the injection, whereas the concentration of an α2-globulin, named pig major acute phase protein (pig-MAP), increases at least 15-fold. A molecular mass of 115 kDa for pig-MAP was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This protein did not crossreact with antisera to human hemopexin, ceruloplasmin, H-kininogen and complement factor C3. Albumin and α-lipoprotein were negative acute phase proteins because their concentration significantly decreased during inflammation. Finally, the concentration of α1-acid glycoprotein, fetuin, α1-protease inhibitor, transferrin and α2-macro-globulins, as well as total proteins, did not change significantly during inflammation.
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  • 8
    Publication Date: 2021-05-19
    Description: La playa La Puntilla se encuentra ubicada en la costa noroccidental de La Habana, en el consejo popular Santa Fe, municipio Playa. Este sector costero ha constituido históricamente un importante sitio de recreación para una parte de la población capitalina, el cual ha estado sometido a un intenso grado de utilización. El objetivo del presente trabajo es conocer el comportamiento actual de la playa y comparar los resultados con los obtenidos a finales del 2011. Para lograrlo se realizó un monitoreo trimestral durante el año 2014. En cada ocasión se midieron tres perfiles topográficos y la línea de costa. Se colectó una muestra de sedimento en la anteplaya de cada perfil. Los resultados obtenidos permiten comprobar que, durante el ciclo anual, ocurren variaciones morfológicas poco significativas. El balance sedimentario se comporta como una sucesión natural, de ganancia y pérdida de sedimento en los diferentes sectores, de un trimestre a otro. Durante el período muestreado no se produjo retroceso de la línea de costa, solo fluctuaciones, demostrándose la poca dinámica de la misma. En la playa predomina la arena gruesa de origen biogénico, la cual presenta una alta madurez sedimentaria. Al comparar los resultados del presente monitoreo con el realizado a finales del 2011, se pudo constatar que no existen diferencias significativas. Los resultados obtenidos permiten comprobar que la playa, no solo se mantuvo estable durante el año 2014 dada las pequeñas variaciones registradas por los indicadores evaluados, sino también durante el período 2011-2014.
    Description: La Puntilla Beach is located on the northwest coast of Havana, in Santa Fe People’s Council, Playa municipality. This coastal sector has historically been an important recreational site for some of the capital’s population, and thus subject to an intense use level. The purpose of this study was to determine the current behavior of the beach, and compare results with those obtained by the end of 2011. To achieve this goal, a quarterly monitoring was performed during 2014. On each occasion, three topographic profiles and the coastline were measured. A sediment sample was collected on the foreshore of each profile. The results obtained proved that insignificant morphological changes occur during the annual cycle. Sediment balance behaved as a natural succession of sediment input and loss in different sectors, from one quarter to another. During the monitoring period there was no coastline retreat, only fluctuations, demonstrating its low dynamics. Biogenic coarse sand predominates on the beach, presenting a high sediment maturity. No significant differences were found when comparing the results of this monitoring with those from 2011. The results obtained proved that the beach remained stable not only during 2014, given the small variations registered by the evaluated indicators, but also during the period 2011-2014.
    Description: Published
    Keywords: Puntilla Beach ; Monitoring ; Sediments ; Coastline ; Beach profile ; Playa La Puntilla ; Monitoreo ; Sedimentos ; Línea de costa ; Perfil de playa
    Repository Name: AquaDocs
    Type: Journal Contribution , Not Known
    Format: pp. 113-134
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  • 9
    Publication Date: 2021-05-19
    Description: Se realizó un estudio de las comunidades de moluscos y foraminíferos bentónicos como posibles productores de bioclastos, en la playa de Varadero y zonas aledañas en abril del 2001. Se inventariaron 106 especies de moluscos y 12 de foraminíferos. La riqueza de especies según el índice de Margalef (5,7 - 9,3) y la densidad (190,9-1228,6 ind.m-2) de moluscos fueron altas, mientras que la biomasa fue baja (0,6 - 66,2 g.m-2), debido al pequeño tamaño que tiene la mayoría de las especies recolectadas. La riqueza de especies de foraminíferos fue baja (0,2-0,8), pero las densidades altas (412,1 -16630,5 NFv.m2). No se observó ninguna tendencia espacial en cuanto a la distribución de ambos grupos en la zona de estudio. Se recomienda un estudio que integre las tasas de sedimentación, origen y la edad de los sedimentos para conocer si la tasa de producción actual de bioclastos en la playa Varadero es suficiente para equilibrar la pérdida de sedimento que se está produciendo.
    Description: A study about mollusk and foraminifera benthonic communities as possible bioclast producers in Varadero beach and surrounding areas was carried out in April 2001. One hundred and six species of mollusks and 12 of foraminifera were inventoried. Mollusk species richness according to Margalef index (5.7 – 9.3) and their density (190.9 – 1228.6 ind.m-2) were high, while their biomass was low (0.6 – 66.2 g.m-2), due to the small size of most collected species. Foraminifera species richness (0.2 – 0.8) was low, but their densities were high (412.1 -16630.5 NFv.m-2). No spatial tendency was found in the distribution of both groups in the study area. A study that integrates sedimentation rates, origin and age of sediments is recommended to determine if current bioclastic production rate in Varadero beach is sufficient to balance the sediment losses that are taking place.
    Description: Published
    Keywords: Moluscos ; foraminíferos ; bioclastos ; playa Varadero ; Matanzas ; Cuba
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp. 36-48
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  • 10
    Publication Date: 2021-05-19
    Description: La arena de la playa de Varadero está constituida mayormente por macroalgas calcáreas, moluscos y foraminíferos. El objetivo del presente trabajo fue evaluar la abundancia de las macroalgas productoras de bioclastos en los biotopos sublitorales de la zona. Se realizó la identificación específica de las algas, y se estimó su abundancia y contenido de carbonato de calcio. Se encontraron 45 taxones infragenéricos, 31 de las cuales fueron de los órdenes Corallinales, Nemaliales, Siphonocladales, Bryopsidales y Dasycladales. Predominó el género Halimeda, seguido de un césped formado por Jania spp. y Amphiroa spp. Los valores mayores de cobertura, biomasa y contenido de carbonato de calcio en las macroalgas calcáreas estaban en los fondos rocosos con una fina capa de sedimentos, desde la zona central hacia el extremo Norte; mientras que hacia el Sur del Hotel Oasis no se hallaron comunidades significativas. Al Norte de la Península Hicacos se observaron áreas con pastos marinos y una menor cobertura de macroalgas.
    Description: Sands of Varadero beach are constituted by calcareous macroalgae, mollusks and foraminifera. The objective of the present work was to assess the main characteristics of calcareous macroalgae associations in subtidal biotopes of the area. Calcareous algae were identified, and their abundance and calcium carbonate content were estimated. Forty-five infrageneric taxa of macroalgae were found, 31 of them being calcareous algae belonging to the orders Corallinales, Nemaliales, Siphonocladales, Bryopsidales, and Dasycladales. The genus Halimeda dominated, followed by a turf of Jania spp. and Amphiroa spp. Higher values of coverage, biomass and density of calcium carbonate in calcareous macroalgae were found in rocky bottoms with a thin layer of sediments, from the central zone of the peninsula up to the northern end; while no important quantity of calcareous macroalgae was found south of the Oasis Hotel. Northward of Hicacos peninsula, seagrass areas with a lower cover of macroalgae were observed.
    Description: Published
    Keywords: Macroalgas marinas ; carbonato de calcio ; playa Varadero ; Matanzas ; Cuba
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp. 22-35
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