C12-Helix development in ()n sequences - spectroscopic characterization of Boc-Aib-4(R)Val]-OMe oligomers

The solution conformations of the -hybrid oligopeptides Boc-Aib-4(R)Val]n-OMe (n = 1-8) in organic solvents have been probed by NMR, IR, and CD spectroscopic methods. In the solid state, this peptide series favors C12-helical conformations, which are backbone-expanded analogues of 310 helices in -peptide sequences. NMR studies of the six- (n = 3) and 16-residue (n = 8) peptides reveal that only two NH protons attached the N-terminus residues Aib(1) and 4(R)Val(2) are solvent-exposed. Sequential NiH-Ni+1H NOEs characteristic of local helical conformations are also observed at the residues. IR studies establish that chain extension leads to a large enhancement in the intensities of the hydrogen-bonded NH stretching bands (3343-3280 cm-1), which suggest elongation of intramolecularly hydrogen-bonded structures. The development of C12-helical structures upon lengthening of the sequence is supported by the NMR and IR observations. The CD spectra of the ()n peptides reveal a negative maximum at ca. 206 nm and a positive maximum at ca. 192 nm, spectral feature that are distinct from those of 310 helices in -peptides.

Temperature-Induced Reversible First-Order Single Crystal to Single Crystal Phase Transition in Boc-gamma(4)(R)Val-Val-OH: Interplay of Enthalpy and Entropy

Crystals of Boc-gamma y(4)(R)Val-Val-OH undergo a reversible first-order single crystal to single crystal phase transition at T-c approximate to 205 K from the orthorhombic space group P22(1)2(1) (Z' = 1) to the monoclinic space group P2(1) (Z' = 2) with a hysteresis of similar to 2.1 K. The low-temperature monoclinic form is best described as a nonmerohedral twin with similar to 50% contributions from its two components. The thermal behavior of the dipeptide crystals was characterized by differential scanning calorimetry experiments. Visual changes in birefringence of the sample during heating and cooling cycles on a hot-stage microscope with polarized light supported the phase transition. Variable-temperature unit cell check measurements from 300 to 100 K showed discontinuity in the volume and cell parameters near the transition temperature, supporting the first-order behavior. A detailed comparison of the room-temperature orthorhombic form with the low-temperature (100 K) monoclinic form revealed that the strong hydrogen-bonding motif is retained in both crystal systems, whereas the non-covalent interactions involving side chains of the dipeptide differ significantly, leading to a small change in molecular conformation in the monoclinic form as well as a small reorientation of the molecules along the ac plane. A rigid-body thermal motion analysis (translation, libration, screw; correlation of translation and libration) was performed to study the crystal entropy. The reversible nature of the phase transition is probably the result of an interplay between enthalpy and entropy: the low-temperature monoclinic form is enthalpically favored, whereas the room-temperature orthorhombic form is entropically favored.

The peptide NCbz-Val-Tyr-OMe and aromatic pi-pi interactions

The peptide N-benzyloxycarbonyl-L-valyl-L-tyrosine methyl ester or NCbz-Val-Tyr-OMe (where NCbz is N-benzyloxycarbonyl and OMe indicates the methyl ester), C23H28N2O6, has an extended backbone conformation. The aromatic rings of the Tyr residue and the NCbz group are involved in various attractive intra- and intermolecular aromatic - interactions which stabilize the conformation and packing in the crystal structure, in addition to NH...O and OH...O hydrogen bonds. The aromatic - interactions include parallel-displaced, perpendicular T-shaped, perpendicular L-shaped and inclined orientations.

El régimen de alcaldías y veedurías en el concejo bajomedieval : el alcalde del alarifazgo en Jaén

En los años finales de la Edad Media nos vamos a encontrar en los municipios castellanos con una gran abundancia de oficios tanto de carácter jurisdiccional como fiscalizador (alcaldes y veedores, respectivamente), algunos tenían planta propia y estable, en tanto que otros aparecían y desaparecían de acuerdo con las necesidades del momento. Nos detenemos en particular en la figura del alcalde del alarifazgo, encargado de juzgar y ejecutar de acuerdo con sus competencias en el ámbito del urbanismo.

Panama Railroad Station, Balboa, Canal Zone - Old Timers arriving Jan. 18, 1928

Leonard Carpenter Panama Canal Collection. Photographs: Views of Panama and the Canal. [Box 1] from the Special Collections & Area Studies Department, George A. Smathers Libraries, University of Florida.

U.S. Favorite, Pedro Miguel Lock - Old Timers Trip through the Canal, Jan. 20, 1928

Leonard Carpenter Panama Canal Collection. Photographs: Views of Panama and the Canal. [Box 1] from the Special Collections & Area Studies Department, George A. Smathers Libraries, University of Florida.

U.S. Favorite, Miraflores Locks - Old Timers trip through Canal. Jan. 20, 1928

Leonard Carpenter Panama Canal Collection. Photographs: Views of Panama and the Canal. [Box 1] from the Special Collections & Area Studies Department, George A. Smathers Libraries, University of Florida.

Prado, Balboa, C.Z. - Old Timers Parade. Jan. 18, 1928

Leonard Carpenter Panama Canal Collection. Photographs: Views of Panama and the Canal. [Box 1] from the Special Collections & Area Studies Department, George A. Smathers Libraries, University of Florida.

STREAM Journal, Vol. 6, No. 1, pp 1-21. Jan-March 2007

CONTENTS: Approaches to understanding pond-dike systems in Asia: the POND-LIVE project approach, by Dave Little, Marc Verdegem and Roel Bosma. The contribution of fish ponds to nutrient cycling in integrated farming systems, by P.N. Muendo, J.J. Stoorvogel and Marc Verdegem. Improving the contribution of fishfarming to livelihoods in Northeast Thailand, by Chittra Arjinkit, Roel Bosma, Danai Turongrouang. Benefits of pond-dike systems in Bangladesh, by M.S. Kabir, M.A. Wahab and Marc Verdegem. Common carp increases rohu production in farmers ponds, by Mohammad Mustafizur Rahman, Md. Abdul Wahab and Marc C.J. Verdegem. Improving pond-dike farming systems in the Mekong delta, Vietnam; the Can Tho approach, by Dang Kieu Nhan, Le Thanh Duong, Le Thanh Phong, Roel H. Bosma and Marc C.J. Verdegem. Fuzzy pathways for farm development in Vietnam, by Roel H. Bosma, Le Thanh Phong, and Dang Kieu Nhan.

Una contribución al conocimiento del Dorado (Salminus maxillosus Cuv. y Val.)

Este trabajo surge de la monografía realizada por el autor para optar al título de Doctor en Ciencias Naturales de la Facultad de Ciencias Naturales y Museo, UNLP y trata sobre el pez sudamericano Salminus maxillosus Cuv. y Val., conocido popularmente bajo el nombre de "Dorado", (PDF tiene 72 paginas.)

Ecological significance of seasonal variation in clutch-size of Arctodiaptomus bacillifer in alpine lakes of high altitudes (Val Bognanco) [Translation from: Bollettino di Zoologia 37 491-492, 1970]

This brief paper describes the significance of seasonal variation in clutch-size of the copepod Arctodiaptomus bacillifer in alpine lakes of high altitudes (Val Bognanco). Seasonal dynamics of the zooplankton of these lakes was studied during summer and autumn of 1968 and 1969and results are summarised.

Élevage du silure Heterobranchus longifilis Val. en bassins sans renouvellement d'eau: effets de l'évolution de quelques paramètres chimiques de l'eau sur la croissance et la survie

African catfish (Heterobranchus longifilis Valenciennes, 1840), with a mean weight of 37 g, were raised in 4 m3 concrete tanks, with or without water changes at densities of 10 and 20 fish per m3. The results indicate that, although the low water needs of this catfish offer hope for the productions of 150 tons/hectare/year, water quality must always be monitored.

Feed the future aquaculture project: draft quarterly progress report, Jan-March 2013

The Feed the Future Aquaculture project is a five year transformative investment in aquaculture focused on 20 southern districts in Barisal, Khulna and Dhaka divisions, Bangladesh, which started in October 2011. This report describes the achievements of FtF-Aquaculture project activities implemented during the 6th quarter (January to March 2013) along with cumulative progress on FtF indicators. Due to the seasonality of fish and shrimp production, which is out of sync with the project year, final harvesting of aquaculture production was completed in this quarter. The achievements summarized below relate to progress of project activities. Progress against the FtF indicators that were not reported on previously are now included in this report.