Disease relevance of Convection

• However, it is unlikely that systemic injection of EGF-based bioconjugates can deliver sufficient amounts of the ligand to brain tumors for therapeutic purposes and direct delivery by means of either intratumoral injection or a variant of it such as convection enhanced delivery will be required [1].
• Local convection enhanced delivery of IL4-Pseudomonas exotoxin (NBI-3001) for treatment of patients with recurrent malignant glioma [2].
• In the present study, a hemofiltration technique that uses both convection and diffusion, with a double chamber hemodialyzer composed of high-flux polysulphone and hemophan (paired filtration dialysis--PFD) was evaluated with regard to the beta2M removal capacity during PFD in 8 stable ESRD patients [3].

High impact information on Convection

• Oceanic convection shut down in response to this flow, concentrating the entire cooling of the northern North Atlantic by the colder atmosphere in the uppermost ocean layer [4].
• The occurrence of a basalt-free, highly differentiated crust is in accord with recent models of the planet's thermal evolution and suggests that Mercury has retained a hot interior as a result of a combination of inefficient mantle convection and minimal volcanic heat loss [5].
• Convection is inhibited in Uranus and Neptune when methane reaches an abundance of about 15 times the solar value and in Jupiter and Saturn if the abundance of water is more than about five times the solar value [6].
• However, no atmosphere composed of only CO2 and H2O appears capable of producing mean planetary temperatures even close to 0 degrees C. Rather than by precipitation, aquifer recharge and ground water seepage may have been enabled by hydrothermal convection driven by geothermal heat and heat associated with impacts [7].
• With this method it was shown that pretreatment of rats with BCNU resulted in an increase in both diffusion and convection of paracellular sucrose from perfusate into bile [8].

Biological context of Convection

• The purpose of the present study was to assess the role of diffusion and convection during filtration of Ficoll across the glomerular filter by comparing glomerular sieving coefficients (theta) to neutral fluorescein isothiocyanate (FITC)-Ficoll 70/400 obtained at low (hydropenic) vs raised (normal) glomerular filtration rates (GFRs) [9].
• A mathematical model is developed for the carbon monoxide (CO) uptake by the blood by taking into account the molecular diffusion, convection, facilitated diffusion and the non-equilibrium kinetics of CO with haemoglobin [10].
• Lowering Hct of A rats lowered the arterial O2 concentration (CaO2) and the arterial-mixed venous O2 difference and increased the maximal cardiac output (Qmax) without changes in maximal O2 uptake (VO2 max) or in the product of Qmax x CaO2, circulatory O2 convection at maximal exercise (TO2 max) [11].
• Results were comparable for microwave oven and convection oven hydrolysis of DFP from 5 foods with good correlations for neutral sugar values; r2 = 0.997 for arabinose, 0.925 for galactose, 0.981 for glucose, 0.969 for mannose, and 0.990 for xylose [12].
• Occupational exposure to a mixture of IRR, perhaps some UVR as well as thermal convection effects, can apparently result in morphological changes in the human corneal endothelium [13].

Anatomical context of Convection

• Hindered convection of macromolecules in gels was studied by measuring the sieving coefficient (theta) of narrow fractions of Ficoll (Stokes-Einstein radius, r(s) = 2.7-5.9 nm) in agarose and agarose-dextran membranes, along with the Darcy permeability (kappa) [14].
• Whether this is simply due to altered convection of O2 into the muscle microcirculation or also to [Hb]-dependent diffusive transport of O2 out of the muscle capillary is unknown in humans [15].
• To evaluate the dose dependency in apparent peritoneal permeability (Pd) of benzoic acid as a model compound for a monocarboxylic acid transport system, a kinetic model, which involves changes in the volume and osmolality of the dialysate as well as the diffusion and convection of drugs across the peritoneum, was applied [16].
• The process of gas exchange in systemic capillaries and its surrounding tissue is simulated numerically in a hyperbaric environment, taking into account the molecular diffusion, convection, saturation of haemoglobin with O2 and CO2, and the metabolic activity in the tissue [17].

Associations of Convection with chemical compounds

• Increasing water absorption by decreasing luminal osmolarity resulted in proportional increase of PEG 400 permeation through solvent drag or convection [18].
• The increase in the MTAC of water and urea associated with an increase in convection is most likely due to increased mixing within the interstitium [19].
• Spatially confined solutions of traveling convection rolls are determined numerically for binary mixtures such as ethanol-water [20].
• This Letter is a first study of transient behavior of convection, which is unique in compressible fluids due to the piston effect [21].
• To establish a driving force for convection into the tumor, various maneuvers were attempted to reduce tumor pressure, including treatment with taxanes or prostaglandin E(1), elimination of tumor circulation, and removal of the tumor capsule [22].

Gene context of Convection

• Convection has an advantage over diffusion in the clearance capacity of IL-1ra, but is associated with greater plasma protein losses [23].
• Protein clearances were determined for beta 2-microglobulin, albumin, IgG, fibronectin, and alpha 2-macroglobulin in both periods to examine the influence of crystalloid-induced convection versus "colloid"-induced convection [24].
• Dialysis may remove ecNOS inhibitors and stimulators by convection and, in the latter case, by diffusion. iNOS inducers are removed during dialysis, suggesting the biocompatibility of the dialysis system with the on-line production of ultrapure substitution fluid [25].
• Now substantial UCP2 immunoreactivity has been found within the above transmitter-receptor mismatch regions, suggesting that UCP2 may enhance diffusion and convection of DA and opioid peptides in such regions by generation of local temperature gradients, thereby contributing to a dynamic regulation of VT [26].
• Thus, hydration of the global stratosphere could be especially sensitive to changes of convection over the TP [27].

Analytical, diagnostic and therapeutic context of Convection

• Air convection requirement declined from about 61 ml air/ml O2 at 15 degrees C to 36 ml air/ml O2 at 30 degrees C. Blood convection requirement remained constant at about 44.6 ml blood/ml O2 at 20 degrees C and 30 degrees C with the result that ventilation/perfusion declined from approximately 1.13 to 0.76 [28].
• Renal replacement therapy with high-cutoff hemofilters: Impact of convection and diffusion on cytokine clearances and protein status [23].

References