The oxygen distribution in the retina of six anesthetized macaques was investigated as a model for retinal oxygenation in the human retina in and adjacent to the fovea. P(O2) was measured as a function of retinal depth under normal physiological conditions in light and dark adaptation with O(2) microelectrodes. Oxygen consumption (Q(O2)) of the photoreceptors was extracted by fitting a steady-state diffusion model to P(O2) measurements. In the perifovea, the P(O2) was 48 +/- 13 mmHg (mean and SD) at the choroid and fell to a minimum of 3.8 +/- 1.9 mmHg around the photoreceptor inner segments in dark adaptation, rising again toward the inner retina. The P(O2) in the inner half of the retina in darkness was 17.9 +/- 7.8 mmHg. When averaged over the outer retina, photoreceptor Q(O2) (called Q(av)) was 4.6 +/- 2.3 ml O(2).100 g(-1).min(-1) under dark-adapted conditions. Illumination sufficient to saturate the rods reduced Q(av) to 72 +/- 11% of the dark-adapted value. Both perifoveal and foveal photoreceptors received most of their O(2) from the choroidal circulation. While foveal photoreceptors have more mitochondria, the Q(O2) of photoreceptors in the fovea was 68% of that in the perifovea. Oxygenation in macaque retina was similar to that previously found in cats and other mammals, reinforcing the relevance of nonprimate animal models for the study of retinal oxygenation, but there was a smaller reduction in Q(O2) with light than observed in cats, which may have implications for understanding the influence of light under some clinical conditions.

13A new synthesis method was developed to produce Zinc-biochar nanocomposites 14 from sugarcane bagasse. The modified biochar maintained 1.2 to 2.0 times higher 15 removal efficiency than that of pristine biochar. FTIR, XPS, BET and SEM were used 16 to analysis the physical and chemical properties of the composite adsorbent. Batch 17 sorption experiments were carried out to investigate the adsorption behavior of Cr(VI) 18 by Zinc-biochar. Experimental data were better fitted by pseudo-second-order kinetics 19 equation and Freundlich isotherms model. Thermodynamic analysis indicated that the 20 adsorption process was spontaneous and endothermic. The maximum adsorption of 21 the modified biochar was observed at pH 2.0 with the sorption capacity of 102.66 mg 22 g -1 . The adsorbed Zinc-biochar could be effectively regenerated by 0.5 mol L -1 NaOH 23 solutions and the adsorption ability decreased from 84.16 to 59.75 mg g -1 in the sixth 24 cycles. In conclusion, the porous Zinc-biochar showed great potential advantages in 25 the removal of Cr(VI) from wastewater.26

In this research, chitosan modification of magnetic biochar (CMB) was successfully prepared for effective removal of Cr(VI). Moreover, this study highlighted that the conversion of Eichhornia crassipes into biochar was a promising method for improved management of this highly problematic invasive species. The sorption kinetics, isotherms, thermodynamics, the effects of pH, and background electrolyte on the sorption process were investigated. The results indicated that CMB adsorbed more Cr(VI) (120 mg g À1 ) than that of pristine biochar (30 mg g À1 ). The sorption data could be well illustrated by pseudo-secondorder and Langmuir models. Furthermore, thermodynamic parameters revealed that the sorption reaction was an endothermic and spontaneous process. The adsorption of Cr(VI) was influenced by solution pH and the maximum sorption capacity was achieved at pH 2. The background electrolyte PO 4 3À and SO 4 2À restricted the Cr(VI) sorption. These results are significant for exploring and optimizing the removal of metal ions by the CMB composite.

In this work, beta-cyclodextrin–chitosan modified walnut shell biochars (β-CCWB) were synthesized as a low-cost adsorbent for the removal of heavy metal Cr(vi) from aqueous solutions.

No abstract

No abstract

Hyperoxia has been shown to improve photoreceptor survival in the detached retina. The present work suggests that hyperoxia is protective because it allowed increased photoreceptor oxygen consumption. Whereas normal Po(2)s were maintained at the inner and outer border of the avascular region during hyperoxia, Q(av) was not restored to normal, suggesting that other factors are involved in photoreceptor dysfunction during detachment in addition to insufficient oxygen delivery.

No abstract