The ability to estimate net N mineralization from C decomposition data has the potential to improve our understanding of N dynamics in soil systems. It was the objective of this study to study this relationship using substrates with varying decomposition rates and C/N ratios. Five substrates including sewage sludge, alfalfa (Medicago sativa L.), clover (Trifolium sp.), bermudagrass [Cynodon dactylon (L.) Pers.] and ryegrass (Lolium multiflorum Lam.) were incubated in Crowley silt loam (Typic Albaqualfs) or Captina silt loam (Typic Fragiudults) soil at known soil temperatures and moistures. Concurrent CO2 evolution and soil inorganic N concentrations were measured periodically. A significant linear relationship between N mineralization and CO2 evolution was found experimentally for each substrate. A computer simulation model was developed which used first order kinetics for conversion of substrate C to CO2. Substrate C mineralization rate constants, substrate C/N ratios and microbial efficiency were primary inputs, while substrate, biomass, and soil organic matter were the major compartments of the model. Microbial efficiency was defined for any C pool undergoing decomposition as the ratio of assimilated C to assimilated C plus dissimilated C. An important feature of the approach was the introduction of a fraction with a C/N ratio of protein that decomposed very rapidly for those substrates where initial N mineralization was large while CO2 evolution was small. Model predictions of both CO2 evolution and net N mineralization were in good agreement with experimental results.

The compositions of percolated drainage waters resulting from the use of eight synthesized river waters of the Western USA under conditions of alfalfa (Medicago sativa L.) production in a controlled lysimeter experiment are presented. The compositions are shown to be affected by (i) the composition of the river water used for irrigation; (ii) the fraction of applied water that appeared as drainage water; (iii) the presence or absence of soil CaCO3; (iv) whether or not the drainage water is open to the atmosphere, and (v) the time of year.

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These data suggest that decreases in plasma free-VEGF levels are greater after treatment with aflibercept or bevacizumab compared with ranibizumab at 4 weeks. At 52 and 104 weeks, a greater decrease was observed in bevacizumab versus ranibizumab. Results from 2 subgroups of participants who did not receive injections within at least 1 month and 2 months before collection suggest similar changes in VEGF levels after stopping injections. It is unknown whether VEGF levels return to normal as the drug is cleared from the system or whether the presence of the drug affects the assay's ability to accurately measure free VEGF. No significant associations between VEGF concentration and systemic factors were noted.

A laboratory study was conducted to evaluate the effect of temperature on decomposition in a silt loam soil under saturated (0.32 g/g) and optimal (0.19 g/g) soil water contents. Sewage sludge was the carbon substrate. Cumulative CO2‐C data were obtained for three temperatures (14, 22, and 30°C), and two substrate groups (rapid, intermediate) for the saturated and optimal water contents. Decomposition followed first‐order kinetics. The temperature effect for each substrate and water content was described by regressing the natural logarithm of the first‐order rate constant on the inverse of the absolute temperature. No significant differences in slopes between substrates within a water content were found for these regressions. Slopes were significantly different between water contents. The slopes were −8975 and −2660 K for the unsaturated and saturated soils, respectively. At saturation the much smaller rate of change in the rate constant, k, with temperature (slope) indicated that temperature had a much smaller influence on decomposition rate under saturated than under unsaturated conditions. Intercepts from the above regressions were significantly different between substrates and water contents. For the unsaturated soil, intercepts were 25.86 and 29.41 for the rapid and intermediate substrates, respectively. Parallel intercepts at saturation were 3.48 and 2.36, respectively. Differences in intercepts between water contents combined with slopes resulted in smaller k values for the saturated soil. These results pointed out that a single equation describing the effect of temperature on the first‐order rate constant should not be applied to the decomposition of organic matter in both unsaturated and saturated soils.