LIGHT-INDUCED CHANGES IN THE VESICULAR APPARATUS OF Phycomyces SPORANGIOPHORES DURING THE PHOTOTROPIC RESPONSE

Abstract— We studied the ultrastructure of laterally illuminated stage I sporangiophores of Phycomyces blakesleeanus to determine whether the phototropic response had any structural correlate. Stimulated sporangiophores conserved the distinctive division into the four longitudinal zones described for state I, and showed no significant differences in the distribution of major organelles in the sides proximal and distal to the light source. On the other hand, apical vesicles were asymmetrically distributed, being present in lower numbers in the faster growing (distal) side of the sporangiophore. We suggest that this asymmetrical distribution reflects the differential utilization of vesicles necessary to sustain the corresponding growth rate of each side. Illumination therefore, must affect the rate of vesicle migration and utilization, more than their rate of synthesis.     

The Maxwell tensor for the Liénard-Wiechert field as an exact divergence

A potential for the bounded part of the Maxwell tensor associated to the Liénard-Wiechert field has been obtained by van Weert. In this paper we explicitly derive the non-local potential for the radiative part of such a tensor.     

An approximation to the minimum traveling wave for the delayed diffusive Nicholson's blowflies equation

In this work, we study the approximation of traveling wave solutions propagated at minumum speeds c ₀(h ) of the delayed Nicholson's blowflies equation: In order to do that, we construct a subsolution and a super solution to (?). Also, through that construction, an alternative proof of the existence of traveling waves moving at minimum speed is given. Our basic hypothesis is that p /δ ∈(1,e ] and then, the monostability of the reaction term. Copyright © 2017 John Wiley & Sons, Ltd.     

Monitoring of tropospheric ozone in the ambient air with passive samplers

Two sampling campaigns in suburban places in the north zone of Santa Clara city, Cuba, have been carried out on a weekly base with the use of Radiello passive diffusion tubes in order to monitor the tropospheric ozone (O₃) levels in 2010. The first campaign was scheduled from February to April (cold season) and the second one in August and October (warm season), both of them at two sampling sites, i.e., Farm and School of Art Instructors. After aqueous extraction, the samples were analyzed by UV–VIS spectrophotometry.A seasonal trend was observed with the maximum O₃ concentrations in the cold season and the minimum levels in the warm season. Samples collected during the cold season showed the highest O₃ levels. Higher levels were reached at the Farm site with average values of about 58 ± 12 μg/m³, which exceeded the limit of the Cuban Standard 99:1999. In the warm season, the O₃ concentrations were similar for both sites, but lower than those observed in the cold season. The overall, seasonal average value was found to be 24 μg/m³. Despite the higher weekly average temperatures in August, the O₃ concentrations during this month showed the lowest values of the whole sampling period, which finding is in agreement with that reported by the Meteorological Institute of Cuba.Mathematical models, based on the Cochrane-Orcutt algorithm, were fitted to the acquired data set to explain the change in the tropospheric ozone concentrations under various meteorological conditions during the two campaigns. The correlation coefficients for both the cold and the warm seasons demonstrated a strong correlation, i.e., 0.779 and 0.951, respectively. The high correlation of wind speed in the model from the first sampling campaign explains the sharp decrease in O₃ concentrations at the SAI sampling site from the sixth week of sampling.     

Enantioselective organocatalytic formal allylation of α-branched aldehydes

Heteroarylvinyl sulfone 1 has been successfully used as a new sulfonyl Michael acceptor in aminocatalytic reactions with branched aldehydes. Subsequent one-pot Julia-Kocienski olefination allows the challenging preparation of enantiomerically pure α-allylated aldehydes bearing C-α quaternary carbons.     

DYNGA: a general purpose QM-MM-MD program. I. Application to water

We present a general purpose QM-MM-MD engine (DYNGA) designed to test alternative hybrid Hamiltonians geared towards the treatment of problems of interest in structural biology including the use of experimental data constraints. In this first presentation we use DYNGA to explore the behaviour of a traditional QM-MM approach in the treatment of the water—water interaction. We find the potential energy hypersurface for the water dimer computed with the HF 4–31G*/TIP3P hybrid Hamiltonian tends to be too flat. We also explore the effect of using traditional QM-MM techniques on proton wires and conclude there is a need for improvement, possibly addressed by using polarizable force fields.     

Availability of Isoflavones (Genistin,Genistein and Daidzein) in Soybean ( Glycine Max ) Curd Treated under High Pressure

The article describes the concentration of isoflavones (genistin, genistein and daidzein) in a Spanish commercial tofu treated under high-pressure. The tofu was subjected to pressure of 400 MPa, in cycles of 10 min each with a total of 4 cycles with the progression of 10, 20, 30 and 40 min, and a temperature of about 10-12 °C. The isoflavones were extracted from tofu with aqueous methanol solution (80:20). The content of isoflavones went up directly proportional to the pressure applied for the first 30 minutes. Afterwards, at 40 min, the values dropped close to the control. Significant differences were found in genistein, genistin and daidzein treated for 20 and 30 min in comparison to control values. Finally, we came to the conclusion that, the isoflavones (genistin, genistein and daidzein) of treated tofu were not destroyed at 400 Mpa for 30 min and a major extraction was observed when compared with the untreated tofu.