Structural and functional properties of the hemoglobin components from the Caspian Sea Acipenser persicus and Acipenser stellatus

Hemoglobin (Hb) variability is a commonly used index of phylogenetic differentiation and molecular adaptation in fish. In the current study, the structural and functional characteristics of Hbs from two Sturgeon species of the Southern Caspian Sea Basin were investigated. After extraction and separation of hemoglobin from whole blood , the polyacrylamide gel electrophoresis (SDSPAGE), native-PAGE and isoelectric focusing (IEF) were used to confirm Hb variability in these fishes. Ion-exchange on CM-cellulose chromatography was used for purification of the dominant Hbs from these fishes. The accuracy of the methods was confirmed by IEF and SDS-PAGE. Spectral studies using fluorescence spectrophotometery, circular dichroism spectropolarimetry (CD) analysis and UV–vis spectrophotometery. Oxygen affinities of these Hbs were compared using Hb-oxygen dissociation curves. Also, the dominant Hbs from these blood fishes were utilized for further experiments. The behavior of Hbs during the denaturation process by n-dodecyl trimethylammonium bromide (DTAB) is investigated by UV–vis spectrophotometer and circular dichroism spectropolarimetry. The thermal denaturation properties of the Hbs wereinvestigated by differential scanning calorimetry (DSC) and Hbs aggregation performed chemically in the presence of dithiotreitol (DTT) by UV–vis spectrophotometer and chemometric study. The results demonstrate a significant relationship between stability of fish hemoglobins and the ability of fish for entering to deeper depths. The UV–Vis absorption spectra identified species of hemoglobin and showed the concentration of oxyHb and metHb decreases and deoxyHb increases upon interaction with DTAB. Besides the UV–vis spectrophotometry, the interaction of DTAB with hemoglobins has been studied using circular dichroism spectropolarimetry analysis. This experiment was utilized to measure the unfolding mechanism and compared alpha-helix secondary structure under different conditions for Hbs. The results reveal that the Acipenser stellatus Hb in comparison with Acipenser persicus Hb has more stability and more structural compactness. Besides, the results confirm the hypothesis that there is a meaningful relation between average habitat depth, partial oxygen pressure, oxygen affinity, structural compactness of Hb, and its stability.

Chemical forms of copper, zinc, lead and cadmium in sediments of the northern part of the Red Sea, Egypt

Total concentrations and chemical forms of heavy metals in sediment samples from the Gulf of Suez and the northern part of the Red Sea, collected during January 2003, were determined by atomic absorption spectrometry. Maximum concentrations of 49.56, 65.42, 33.52 and 3.52 µg/g were recorded for total Cu, Zn, Pb and Cd respectively at Adabiya location. These may reflect the high contribution of land-based activities in the northern part of the Gulf. Also, high percentages of heavy metals were found in the residual fraction (Cu=78.61, Zn=77.10 and Pb=66.80%) while a high percentage of Cd was found in the carbonate fraction (45.82%). However, few or negligible percentages were recorded in the exchangeable fractions (Cu=0.51, Zn=1.57 and Pb=1.74%). Concentration of Cd in the exchangeable fraction was too low to be detected.

Copper and manganese forms in Lake Edku sediments, Alexandria, Egypt

Lake Edku is one of the Nile Delta lakes. It is subjected to contaminations by several anthropogenic materials such as trace elements and other wastes. The distribution of the different chemical forms of copper and manganese has been studied using sequential extraction techniques. Chemical analysis of the sediments shows that CaCO sub(3) ranged from 3.7% to 9.6% and organic matter from 3.06% to 8.11%. The results indicate that the distribution of manganese among the six chemical forms in the sediments of the lake obeys the following order: Mn-residual>Mn-carbonate>Mn-moderately reducible>Mn-organic form>Mn-exchangeable > Mn-easily reducible fraction. Also, the data revealed that more than 50% of the total manganese was found in the residual form, while the remainder was distributed among the other forms. In contrast, more than 70% of the total copper content was associated with the five chemical forms (exchangeable, carbonate, easily and moderately reducible and organic forms). Generally, the enrichment of manganese in the residual form revealed the important role in building up of clay minerals, while the distribution of copper among the different forms reflects an important role in biological and biochemical processes.

Value-adding through coatings

The paper presents the three categories of food coatings that are used, individually or in combination, to produce battered or breaded foods. These are predust, batters and breadcrumbs. Predusts are usually a blend of flours, starches and other functional ingredients such as proteins, vegetable gums and seasonings or flavors; batters are blends of flours, starches, leavening agents and seasonings which, when mixed with water, forms a viscous liquid used to evenly coat a food item; while breadcrumbs are baked or otherwise thermally processed cereal-based ingredients which are applied to a moistened food item prior to cooking.

An approach to functional synthesis of solutions in mechanical conceptual design. Part III: Spatial configuration

These three papers describe an approach to the synthesis of solutions to a class of mechanical design problems; these involve transmission and transformation of mechanical forces and motion, and can be described by a set of inputs and outputs. The approach involves (1) identifying a set of primary functional elements and rules of combining them, and (2) developing appropriate representations and reasoning procedures for synthesising solution concepts using these elements and their combination rules; these synthesis procedures can produce an exhaustive set of solution concepts, in terms of their topological as well as spatial configurations, to a given design problem. This paper (Part III) describes a constraint propagation procedure which, using a knowledge base of spatial information about a set of primary functional elements, can produce possible spatial configurations of solution concepts generated in Part II.

Simple and functional photonic devices from printable liquid crystal lasers

In this paper we demonstrate laser emission from emulsion-based polymer dispersed liquid crystals. Such lasers can be easily formed on single substrates with no alignment layers. Remarkably, it is shown that there can exist two radically different laser emission profiles, namely, photonic band-edge lasing and non-resonant random lasing. The emission is controlled by simple changes in the emulsification procedure. Low mixing speeds generate larger droplets that favor photonic band edge lasing with the requisite helical alignment produced by film shrinkage. Higher mixing speeds generate small droplets, which facilitate random lasing by a non-resonant scattering feedback process. Lasing thresholds and linewidth data are presented showing the potential of controllable linewidth lasing sources. Sequential and stacked layers demonstrate the possibility of achieving complex, simultaneous multi-wavelength and "white-light" laser output from a wide variety of substrates including glass, metallic, paper and flexible plastic. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).