Companion cells represent a major component of the phloem, the plant vascular tissue system responsible for long-distance transport of organic nutrients from the sites of synthesis (source organs) to sites of utilization (sink organs). The companion cells are intimately associated with phloem sieve elements, which make up the actual transport vessel (sieve tube) through which mass flow of assim...

In Codeplay’s Sieve C++, the programmer can place code inside a “sieve block” thereby instructing the compiler to delay writes to global memory and apply them in order on exit from the block. The semantics of sieve blocks makes code more amenable to automatic parallelisation. However, strictly queueing writes until the end of a sieve block incurs overheads and is typically unnecessary. If the p...

Ca2+-binding proteins in the watery saliva of Megoura viciae counteract Ca2+-dependent occlusion of sieve plates in Vicia faba and so prevent the shut-down of food supply in response to stylet penetration. The question arises whether this interaction between aphid saliva and sieve-element proteins is a universal phenomenon as inferred by the coincidence between sieve-tube occlusion and salivati...

The distribution of solutes in the various cells of sugar beet (Beta vulgaris L.) source leaves, petioles, and sink leaves was studied in tissue prepared by freeze-substitution. The differences in degree of cryoprotection indicated that sieve elements and companion cells of the source leaf, petiole, and sink leaf contain a high concentration of solute. The osmotic pressure of various types of c...

Despite the critical role that phloem plays in a number of plant functional processes and the potential impact of water stress on phloem structural and phloem sap compositional characteristics, little research has been done to examine how water stress influences phloem transport. The objectives of this study were to develop a more accurate understanding of how water stress affects phloem transp...

introduction: diode laser irradiation has recently shown promising results for treatment of gingival pigmentation. this study sought to compare the efficacy of 2 diode laser irradiation protocols for treatment of gingival pigmentations, namely the conventional method and the sieve method. methods: in this split-mouth clinical trial, 15 patients with gingival pigmentation were selected and their...