Predicting the response of Hamilton Harbour to the nutrient loading reductions: A modeling analysis of the “ecological unknowns”

We examine the likelihood of delisting the Hamilton Harbour as an Area of Concern, if the nutrient loading reductions proposed by the Remedial Action Plan are actually implemented. Our analysis suggests that the chl a criterion of 10 μg L^{− 1} is achievable, but the water quality setting process should explicitly accommodate the natural variability by allowing for a realistic percentage of violations, e.g., exceedences of less than 10–15% of the weekly samples during the stratified period should still be considered as compliance of the system. The current epilimnetic total phosphorus criterion of 17 μg L^{− 1} is probably stringent and therefore a somewhat higher value (e.g., 20 μg L^{− 1}) may provide a more realistic goal. Phosphorus dynamics in the sediment–water column interface need to be revisited, as the internal nutrient loading can conceivably be a regulatory factor of the duration of the transient phase and the recovery resilience of the Harbour. We also pinpoint two critical aspects of the system dynamics that invite further investigation and will likely determine our predictive capacity to assess compliance with the chlorophyll a criterion of 10 μg L^{− 1}, i.e., the nutrient recycling mediated by the microbial food web and the structural shifts towards a zooplankton community dominated by large-sized and fast-growing herbivores. The latter prospect highlights the notion that the bottom-up (i.e., nutrient loading reduction) approach historically followed in the Harbour was sufficient to bring the system in its present state, but any further improvements should be viewed in the context of a combined bottom-up and top-down (i.e., alleviation of the zooplanktivorous pressure) control.     

Influence of the electron acceptor on nitrite reductase gene (nir) diversity in an activated sludge community

Analyses of the nitrite reductase gene diversities (nirK and nirS) in an activated sludge community fed with both nitrite and glucose were conducted. Results suggest that the topology of nirK and nirS gene fragment-based phylogenetic trees is influenced more by the available electron acceptor than by the carbon source. A denitrification reactor was operated for 53 days and a clone library constructed when the denitrifying communities in the SBR were supplied with both nitrite and glucose. Half of the nirK and nearly all the nirS gene fragments formed a cluster that was separate from a cluster containing nirK and nirS sequences derived from other communities in nitrate-fed reactors. On the other hand, nirK and nirS fragments obtained with glucose as the carbon source were similar to those detected in communities fed with other carbon sources.     

Influence of fibre length and filler particle size on pore structure and mechanical strength of filler‐containing paper

Test sheets were prepared by incorporating softwood pulp with silica filler, PW‐5 (diameter 4.5 μm) or PW‐20 (15 μm). Length‐weighted averages of fibre were 2.5 (uncut fibre) and 1.25 mm (short‐cut fibre). Pore sizes less than 150 urn were measured by mercury porosimeter. Sheets of short‐cut fibres and mixed with uncut fibres at ratio of 3:1 or 1:3 had larger pore volumes than others tested. When filler content increased, the total pore volume increased for PW‐20 sheets, but it did not for PW‐5 sheets with short‐cut fibres. Tensile index and folding endurance were very much affected by fibre length. Contact number on a fibre was calculated by computer simulation, and it had a linear relation with tensile index of sheet.     

STABILITY OF STRONTIUM(II) AND BARIOM(II) COMPLEXES WITH 18-CROWN-6 IN AQUEOUS SOLUTION AND THEIR EXTRACTABILITY AS PICRATES

When strontium(II) and barium(II) were extracted with 18-crown-6(l 8C6) and picrate ions into chloroform, log(distribution ratio of metal(II)) approached flat in a higher region of log[18C6], although it is reported that the distribution ratio of copper(II) or zinc(II) increases in proportion to the second order of 118C6]. From the extraction data analysis, the flat distribution ratio was explained by the formation of the aqueous complex with 18C6 and the stability constants for strontium(II) and barium(II) were determined to be 2.89 and 3.68 as logβ1respectively.     

Determination of unsaturated fatty acid composition by high-resolution nuclear magnetic resonance spectroscopy

High-resolution nuclear magnetic resonance (NMR) spectroscopy provides useful data for analyzing fatty acid compositions of edible vegetable oils. Quantitation of each fatty acid was carried out by evaluation of particular peaks. According to the ¹H NMR method, terminal methyl protons, divinyl protons, and allyl protons are useful to calculate linolenic acid, linoleic acid, and oleic acid, respectively. The ω-2 carbon, divinyl carbon, and allylic carbons were used for calculation of these acids by the ¹³C NMR method. Compositional results obtained by NMR coincided well with those of the conventional gas chromatography (GC) method. Results from ¹³C NMR were in better agreement with those from GC than were the results obtained by the ¹H NMR method.     

Iodine Excess as an Environmental Risk Factor for Autoimmune Thyroid Disease

The global effort to prevent iodine deficiency disorders through iodine supplementation, such as universal salt iodization, has achieved impressive progress during the last few decades. However, iodine excess, due to extensive environmental iodine exposure in addition to poor monitoring, is currently a more frequent occurrence than iodine deficiency. Iodine excess is a precipitating environmental factor in the development of autoimmune thyroid disease. Excessive amounts of iodide have been linked to the development of autoimmune thyroiditis in humans and animals, while intrathyroidal depletion of iodine prevents disease in animal strains susceptible to severe thyroiditis. Although the mechanisms by which iodide induces thyroiditis are still unclear, several mechanisms have been proposed: (1) excess iodine induces the production of cytokines and chemokines that can recruit immunocompetent cells to the thyroid; (2) processing excess iodine in thyroid epithelial cells may result in elevated levels of oxidative stress, leading to harmful lipid oxidation and thyroid tissue injuries; and (3) iodine incorporation in the protein chain of thyroglobulin may augment the antigenicity of this molecule. This review will summarize the current knowledge regarding excess iodide as an environmental toxicant and relate it to the development of autoimmune thyroid disease.     

Formal Nucleophilic Boryl Substitution of Organic Halides with Silylborane/Alkoxy Base System

Boryl substitution of organohalides with a silylborane and alkoxy bases is described. This reaction can be applied to various functionalized aryl halides. Alkyl and alkenyl halides, and even sterically congested aryl bromides also provided the corresponding borylated products in high yields. Mechanistic studies indicated that neither trace transition-metal impurities nor aryl radical species involved in this reaction.