Gamal El-Ghazaly

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Mature pollen grains ofNymphaea mexicana have a verrucate proximal surface, a psilate distal surface and an anazonasulculus (encircling-sulcate aperture). The developmental events of microspores and tapetal cells were observed with TEM and SEM. Radially oriented substructural elements are seen in the microspore surface coating ofNymphaea mexicana from the(More)
Orbicules, or Ubisch bodies, are sporopollenin particles lining the inner tangential and sometimes also the radial tapetal cell walls. They occur only in species with a secretory tapetum. The surface ornamentation of orbicules and pollen of the same species is often strikingly similar. Although orbicules were discovered more than a century ago, these(More)
Although intact pollen grains are assumed to be the primary carrier of pollen allergens, specific immunoreactive components have been found in other aerosol fractions, e.g., starch grains and remains of tapetal cells Cryo-scanning-electron-microscopy results demonstrate the presence of a clear network of strands connecting the tapetum with the microspores.(More)
Anthers ofBetula pendula were collected at regular intervals during the dormancy period until anthesis. Ultrathin sections of maturing pollen grains were especially stained for polysaccharides and proteins and examined with TEM to determine whether structural or/and chemical changes in the pollen wall occur during the dormancy period of the plant life(More)
Pollen grain polarity, aperture condition and pollen tube formation were examined inEphedra americana, E. foliata, E. rupestris, E. distachya, andE. fragilis using LM, SEM and TEM. In the characteristic oblate pollen, as seen in situ in the tetrad configuration, the polar axis is the minor one and the equatorial plane runs between the two narrow ends of the(More)
 The Callitrichaceae are a monogeneric family of aquatic angiosperms comprising approximately 50 terrestrial, amphibious, and obligately submersed species. Callitriche is unique in being the only known genus with co-occurring aerial and underwater pollination systems. Mature pollen structure is correlated with growth habit, pollination biology, and(More)
This paper deals with the design of a new robust adaptive controller for parallel manipulators based on sliding mode and modelbased adaptive control. More precisely, the proposed controller relies on continuous finite-time terminal sliding mode (TSM) control and the linear-in-the-parameters property of the inverse dynamics of the manipulator. The main(More)
Traditional underwater vehicle-manipulator systems (UVMS) consist mainly of an underwater vehicle on which a manipulator is mounted. In addition to the vehicle thrusters, this paper proposes to use cables to actuate UVMSs. The main goal of this extra source of actuation is to enhance UVMS work capabilities. Similarly to cable-driven parallel robots, the(More)
In mature megaspores of Selaginella diffusa (C. Presl) Spring the units of the exospore are ordered and become unordered toward the outer and inner surfaces. The exospore surface is coated with silica at maturity. The insertion of the future gap begins in early stages with formation of many minigaps within the inner part of the exospore distally. The(More)
This paper deals with cable-driven mobile platforms that are equipped with a serial robot. The contribution of this paper is twofold. First, a method to determine the maximum payload handled by the serial robot while the mobile platform is maintained in equilibrium by cables is presented. A mobile platform pose is wrench feasible if cables can balance any(More)
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