http://dns2.asia.edu.tw/~ysho/YSHO-English/1000%20WC/PDF/Pro%20Bio34,%20451.pdf

Pseudo-second order model for sorption processes

The T-sensor is a recently developed microfluidic chemical measurement device that exploits the low Reynolds number flow conditions in microfabricated channels. The interdiffusion and resulting chemical interaction of components from two or more input fluid streams can be monitored optically, allowing measurement of analyte concentrations on a continuous basis. In a simple form of T-sensor, the concentration of a target analyte is determined by measuring fluorescence intensity in a region where the analyte and a fluorescent indicator have interdiffused. An analytical model has been developed that predicts device behavior from the diffusion coefficients of the analyte, indicator, and analyte-indicator complex and from the kinetics of the complex formation. Diffusion coefficients depend on the local viscosity which, in turn, depends on local concentrations of all analytes. These relationships, as well as reaction equilibria, are often unknown. A rapid method for determining these unknown parameters by interpreting T-sensor experiments through the model is presented.

/pdf/quantitative-analysis-of-molecular-interaction-in-a-8oaw4n6e82.pdf

Quantitative Analysis of Molecular Interaction in a Microfluidic Channel: The T-Sensor

https://www.cell.com/trends/plant-science/pdf/S1360-1385(01)01898-2.pdf

Peroxisomes as a source of reactive oxygen species and nitric oxide signal molecules in plant cells.

Peroxisomes are subcellular organelles with an essentially oxidative type of metabolism. Like chloroplasts and mitochondria, plant peroxisomes also produce superoxide radicals (O .- 2 ) and there are, at least, two sites of superoxide generation: one in the organelle matrix, the generating system being xanthine oxidase, and another site in the peroxisomal membranes dependent on NAD(P)H. In peroxisomal membranes, three integral polypeptides (PMPs) with molecular masses of 18, 29 and 32 kDa have been shown to generate O .- 2 radicals. Besides catalase, several antioxidative systems have been demonstrated in plant peroxisomes, including different superoxide dismutases, the ascorbate-glutathione cycle, and three NADP-dependent dehydrogenases. A CuZn-SOD and two Mn-SODs have been purified and characterized from different types of peroxisomes. The four enzymes of the ascorbate-glutathione cycle (ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase) as well as the antioxidants glutathione and ascorbate have been found in plant peroxisomes. The recycling of NADPH from NADP + can be carried out in peroxisomes by three dehydrogenases: glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and isocitrate dehydrogenase. In the last decade, different experimental evidence has suggested the existence of cellular functions for peroxisomes related to reactive oxygen species (ROS), but the recent demonstration of the presence of nitric oxide synthase (NOS) in plant peroxisomes implies that these organelles could also have a function in plant cells as a source of signal molecules like nitric oxide (NO), superoxide radicals, hydrogen peroxide, and possibly S-nitrosoglutathione (GSNO).

/pdf/reactive-oxygen-species-antioxidant-systems-and-nitric-oxide-5a28vlnenz.pdf

Reactive oxygen species, antioxidant systems and nitric oxide in peroxisomes

Senescence is a genetically regulated oxidative process that involves a general degradation of the cellular structures and enzymes and the mobilization of the products of degradation to other parts of the plant. Senescence is mainly characterized by a cessation of photosynthesis, disintegration of

/pdf/the-activated-oxygen-role-of-peroxisomes-in-senescence-2pi9lu9ei3.pdf

The Activated Oxygen Role of Peroxisomes in Senescence

A role for leaf peroxisomes in the catabolism of purines

Adsorption of Water Vapor by Homoionic Montmorillonites. Heats of Adsorption and Desorption

Dissipation of racemic mecoprop and dichlorprop and their pure R-enantiomers in three calcareous soils with and without peat addition.

SUMMARY

The adsorption of carbendazim by peat and montmorillonite was studied as a function of the exchangeable cations and temperature. The adsorption on soils was also studied.



The kinetics of carbendazim adsorption on peat showed that adsorption equilibrium was reached within 1 h. The order of adsorption of carbendazim on peat was as follows: H+-peat > Cu2+-peat > Co2+-peat > Mg2+-peat > K+-peat, and the thermodynamic parameters appeared to suggest an adsorption mechanism involving hydrogen bonds, although in the H+, Cu2+ and Co2+ samples a protonation process and adsorption of the protonated species were also likely.



The kinetics of carbendazim adsorption on montmorillonite (mont.) showed that equilibrium was reached within 1 h. The order of adsorption was: H+-mont. > Cu2+-mont. > Co2+-mont. > Ca2+-mont., the adsorption on the H+ and Cu2+ samples being much greater than that on the other samples. For the H+ and Cu2+ samples, the thermodynamic parameters appeared to suggest a double mechanism: physical adsorption, and protonation and adsorption by ion exchange. The most probable mechanism for the adsorption of carbendazim on the Co2+ and Ca2+ samples was physical bonding.



The capacity for adsorption of this fungicide on soil was dependent on the organic matter, nitrogen and clay content, as well as on the cation exchange capacity. No significant correlation was found with pH, C/N ratio or free iron content.

F. Sánchez-Rasero

Papers

A role for leaf peroxisomes in the catabolism of purines

Adsorption of Water Vapor by Homoionic Montmorillonites. Heats of Adsorption and Desorption

Dissipation of racemic mecoprop and dichlorprop and their pure R-enantiomers in three calcareous soils with and without peat addition.

Carbendazim adsorption on montmorillonite, peat and soils

Photodegradation of mecoprop and dichlorprop on dry, moist and amended soil surfaces exposed to sunlight