Biologie moléculaire : accès libre

In order to coordinate plant life and adaptation, unique membrane receptors that interpret both native and foreign cues have evolved. In order to be able to detect ligands of varying chemical compositions, this large family of receptor proteins have developed ectodomains that are very different from one another. Understanding these signaling systems mechanistically will help answer important questions in cell biology. The latest structurally characterized receptor–ligand interactions and regulatory mechanisms, in addition to novel receptor folds, will be the primary focus of this review. Prostaglandins (PGs) are bioactive lipids that have a place with the eicosanoid class of mixtures. Prostaglandins are known for regulating inflammation, vasodilation, and platelet aggregation, among other physiologic and pathologic functions. Some aspects of the outcome of immune responses, particularly T cell trafficking and diapedesis are influenced indirectly by these characteristics alone. However, PGs also have direct effects on immune system cells that are heavily dependent on the microenvironment during exposure.

Pre-carbonized date palm leaves (Phoenix dactylifera L.) with a particle size of 10 microns were used to prepare activated carbon pellets by KOH activation at 700°C. The grain powders were impregnated in KOH at a concentration of (0.0–0.35) moles, converted into grain pellets by applying 12 metric tons of pressure. The activated carbon produced was analyzed in terms of crystallite parameters, specific surface area, Young’s modulus (E) and spring length (S_P) between two cubic granular volume microstructures. The crystallite parameters were analyzed in terms of (d₀₀₂, L_c and L_a) for the graphitic crystallite. The results show that the L_a increased with increasing KOH concentration, while there is now a significant change to the L_c. The specific surface area of the AC product was found in the range of 1400–1684.5 m²/g, an empirical method proposed by Emmerich FG and Luengo CA has been used to estimate the E from its crystallite parameters. The E has systematically varied with KOH concentration, and 0.25 M is a higher E than the others. The estimated Young’s modulus from the empirical methods was in good agreement with that measured by ultrasonic techniques, indicating that the behavior of Young’s modulus is related to the crystallite parameters. The spring length (S_p) that fluctuated in the AC shows a critical length of 3.72, which is close to that of the crystallite parameter (d₀₀₂) when it was activated by 0.25 M concentration. These results indicate that the crystallite parameters can play an essential role in the phonotypic and descriptive properties of the AC pellets, indicating the applicability of this method for estimating the mechanical properties of the carbon materials.

Activated carbon pellets (ACPs), precursor (palm leaves) (Phoenix dactylifera L.), are primarily heated at low temperatures and milled into a fine grain powder to produce self-adhesive properties. The grain powders produced were impregnated in KOH solutions having a concentration of 0–0.35 moles (M) and pelletized by applying 12 metric tons of pressure, before being carbonized at 700°C, in a nitrogen environment. The thermal gravimetric analysis (TGA) and differential thermal gravimetric analysis (DTGA) were carried out on the pre-carbonized date palm leaves. The results showed that with increasing KOH concentration, the weight loss of the sample markedly decreased. The young modulus (E) showed that 0.25 M has a higher value of 10.6 GPs than the others, indicating better grain particle alignment. The porosity (B) of the AC was estimated empirically by adjusting the values of B to have a straight line with a slope of ≈ 2. The results found that the porosities of the AC fluctuated in a range of 0.39–48 with the KOH concentration. The electrical conductivity (σ) of the AC showed that 0.2 M was a higher value than the others, indicating that more mobility carried in the sample. The percolation theory was found to have a good correlation with the bulk density of the carbon samples, and this was interpreted by the increase in the bulk density of the AC sample above the critical density of 0.45 g/cm³ for the E and above the critical density of 0.045 g/cm³.