Substituent effects on azo dye oxidation by the FeIII-EDTA-H2O2 system

Toxicity potentials are scaling factors used in life cycle assessment (LCA) indicating their relative importance in terms of potential toxic impacts. This paper presents the results of an uncertainty assessment of toxicity potentials for 181 substances that were calculated with the global nested multi-media fate, exposure and effects model USES-LCA. The variance in toxicity potentials resulting from choices in the modelling procedure was quantified by means of scenario analysis. A first scenario analysis showed to what extent potential impacts in the relatively short term are obscured by the inclusion of impacts on the very long term. Toxicity potentials representing potential impacts over time horizons of 20, 100 and 500 years were compared with toxicity potentials representing potential impacts over an infinite time horizon. Time horizon dependent differences up to 6.5 orders of magnitude were found for metal toxicity potentials, while for toxicity potentials of organic substances under study, differences remain within 0.5 orders of magnitude. The second scenario analysis addressed to what extent potential impacts on the continental scale are obscured by the inclusion of impacts on the global scale. Exclusion of potential impacts on the global scale changed the toxicity potentials of metals and volatile persistent halogenated organics up to 2.3 orders of magnitude. These scenario analyses also provide the basis for determining exports to future generations and outside the emission area.     

Effect of complex nitrogen source on the synthesis and accumulation of poly(3-hydroxybutyric acid) by recombinantEscherichia coli in flask and fed-batch cultures

When a recombinantEscherichia coli XL1-Blue harboring pSYL105 was cultured in a complex medium, a poly(3-hydroxybutyric acid) (PHB) concentration of 7.16 g/L was obtained in 48 h. However, a PHB concentration of only 0.91 g/L was obtained in 60 h by culturing in a defined medium. Also, fed-batch culture in a defined medium resulted in considerably lower PHB accumulation than in a complex medium. With the aim to produce a high concentration of PHB at a reduced medium cost, we examined 10 complex nitrogen sources for their ability to promote PHB synthesis in a defined medium. Tryptone, casamino acids, and casein hydrolysate promoted PHB synthesis to a higher extent than the others tested. PHB synthesis was also enhanced during fedbatch cultures when a defined medium was supplemented with various complex nitrogen sources. With tryptone supplementation a PHB concentration of 66.7 g/L could be obtained in 44 h. Yeast extract was less effective for promoting PHB synthesis than tryptone. Corn steep liquor, which did not enhance PHB synthesis significantly, could promote PHB synthesis considerably when supplemented together with yeast extract in both flask and fed-batch cultures.     

Multiple dimensions of human resource development and organizational performance

Building on strategic human resource management literature, this study investigates the effects of various human resource development (HRD) dimensions on organizational performance. We identify four distinct dimensions of HRD that reflect either quantitative or qualitative approaches from either managerial or employee perspectives. Furthermore, we propose that HRD affects organizational performance by shaping employee outcomes, a prevailing but rarely tested assumption. Multi‐source data collected from 207 manufacturing companies at three time points over a 5‐year period largely support our theoretical propositions. A series of structural path analyses confirm that HRD improves employee commitment and competence, which in turn determine the financial performance of the organization. The quantitative dimensions of HRD (resource investment in HRD) predict only employee commitment. By contrast, the qualitative dimensions of HRD (management support for, and perceived benefits of, HRD) enhance both employee commitment and competence. Our analysis also demonstrates synergistic interactions between the quantitative and qualitative dimensions of HRD in predicting employee outcomes. This study elaborates the distinct values of different dimensions of HRD and highlights the significance of employee outcomes as the mediating mechanism between HRD and firm performance. Copyright © 2014 John Wiley & Sons, Ltd.     

Thermal Properties and Biodegradability Studies of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

For investigating the relationship between thermal properties and biodegradability of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), several films of PHBV containing different polyhydroxyvalerate (HV) fractions were subjected to degradation in different conditions for up to 49 days. Differential scanning calorimetry (DSC), thermogravimetry (TG), specimen weight loss and scanning electron microscopy (SEM) were performed to characterize the thermal properties and enzymatic biodegradability of PHBV. The experimental results suggest that the degradation rates of PHBV films increase with decreasing crystallinity; the degradability of PHBV occurring from the surface is very significant under enzymatic hydrolysis; the crystallinity of PHBV decreased with the increase of HV fraction in PHBV; and no decrease in molecular weight was observed in the partially-degraded polymer.     

Distinct effects of intrinsic motivation and extrinsic rewards on radical and incremental creativity: The moderating role of goal orientations

Previous studies have investigated the role of intrinsic motivation and extrinsic rewards in enhancing employee creativity. However, the possibility that these motivational factors affect the creativity of different types remains largely unexplored, particularly in the organizational settings. Moreover, the potential that personality traits may moderate the function of these motivational factors toward creativity is another underresearched area. By drawing on the person–situation interaction perspective, we propose that both intrinsic motivation and extrinsic rewards predict creativity but of different types. Thus, we diverge from the view that creativity is a uniform criterion domain by adopting the distinction between radical and incremental creativity. Our empirical analysis of 220 independent employee–supervisor dyads confirmed that intrinsic motivation and extrinsic rewards predict radical and incremental creativity, respectively. Moreover, the effects of intrinsic motivation on radical and incremental creativity are more positive for employees with higher learning goal orientation. By contrast, the effect of extrinsic rewards on incremental creativity is more positive for employees with higher performance goal orientation. This study offers elaborate and nuanced perspectives and insights into the role of different motivational processes in the development of different types of creativity.     

A comparison study of the potential risks induced in arable land and forest soils by carcass-derived pollutants

Environmental Geochemistry and Health - Improper decisions concerning animal carcass disposal sites pose grave threats to environmental biosecurity. However, only a few studies have focused on the...     

Harnessing dark fermentative hydrogen from pretreated mixture of food waste and sewage sludge under sequencing batch mode

Food waste and sewage sludge are the most abundant and problematic organic wastes in any society. Mixture of these two wastes may provide appropriate substrate condition for dark fermentative biohydrogen production based on synergistic mutual benefits. This work evaluates continuous hydrogen production from the cosubstrate of food waste and sewage sludge to verify mechanisms of performance improvement in anaerobic sequencing batch reactors. Volatile solid concentration and mixing ratio of food waste and sludge were adjusted to 5 % and 80:20, respectively. Five different hydraulic retention times (HRT) of 36, 42, 48, 72, and 108 h were tested using anaerobic sequencing batch reactors to find out optimal operating condition. Results show that the best performance was achieved at HRT 72 h, where the hydrogen yield, the hydrogen production rate, and hydrogen content were 62.0 mL H₂/g VS, 1.0 L H₂/L/day, and ~50 %, respectively. Sufficient solid retention time (143 h) and proper loading rate (8.2 g COD/L/day as carbohydrate) at HRT 72h led to the enhanced performance with better hydrogen production showing appropriate n-butyrate/acetate (B/A) ratio of 2.6. Analytical result of terminal-restriction fragment length polymorphism revealed that specific peaks associated with Clostridium sp. and Bacillus sp. were strongly related to enhanced hydrogen production from the cosubstrate of food waste and sewage sludge.     

Development and implementation of surface water quality standards for protection of human health in Korea

Current water quality standards for the protection of human health in Korea include 17 substances found in rivers and streams. Due to increasing concern over the release of hazardous chemicals into the aquatic environment, there has been a demand for additional water quality standards. Therefore, the Korean Ministry of the Environment plans to gradually increase the number of water quality standards to 30 substances, including 22 substances for protection of human health and 8 substances for protection of aquatic ecosystems by 2015. In this study, new water quality standards for protection of human health were established for 1,4-dioxane, formaldehyde, and hexachlorobenzene. We selected candidate hazardous chemicals, conducted a human health risk assessment to determine priority chemicals, established water quality standards based on technical analyses and comparison with domestic and developed countries’ water quality standards, and conducted an expert review. Water quality standards for protection of aquatic ecosystems will be derived in the near future. This study describes how the water quality standards for protection of human health were developed and implemented. Current status, recent expansion, and future plans for water quality standards in Korea are also covered.     

Impact of metal stress on the production of secondary metabolites in <Emphasis Type="Italic">Pteris vittata</Emphasis> L. and associated rhizosphere bacterial communities

Plants adapt to metal stress by modifying their metabolism including the production of secondary metabolites in plant tissues. Such changes may impact the diversity and functions of plant associated microbial communities. Our study aimed to evaluate the influence of metals on the secondary metabolism of plants and the indirect impact on rhizosphere bacterial communities. We then compared the secondary metabolites of the hyperaccumulator Pteris vittata L. collected from a contaminated mining site to a non-contaminated site in Vietnam and identified the discriminant metabolites. Our data showed a significant increase in chlorogenic acid derivatives and A-type procyanidin in plant roots at the contaminated site. We hypothesized that the intensive production of these compounds could be part of the antioxidant defense mechanism in response to metals. In parallel, the structure and diversity of bulk soil and rhizosphere communities was studied using high-throughput sequencing. The results showed strong differences in bacterial composition, characterized by the dominance of Proteobacteria and Nitrospira in the contaminated bulk soil, and the enrichment of some potential human pathogens, i.e., Acinetobacter, Mycobacterium, and Cupriavidus in P. vittata’s rhizosphere at the mining site. Overall, metal pollution modified the production of P. vittata secondary metabolites and altered the diversity and structure of bacterial communities. Further investigations are needed to understand whether the plant recruits specific bacteria to adapt to metal stress.     

Enhanced degradation of polycyclic aromatic hydrocarbons by biodegradation combined with a modified Fenton reaction

A study has been conducted to enhance degradation of a mixture of polycyclic aromatic hydrocarbons (PAHs) by combining biodegradation with hydrogen peroxide oxidation in a former manufactured gas plant (MGP) soil. An active bacterial consortium enriched from the MGP surface soil (0-2 m) biodegraded more than 90% of PAHs including 2-, 3-, and 4-ring hydrocarbons in a model soil. The consortium was also able to transform about 50% of 4- and 5-ring hydrocarbons in the MGP soil. As a chemical oxidant, Fenton's reagent (H2O2 + Fe2+) was very efficient in the destruction of a mixture of PAHs (i.e., naphthalene (NAP), fluorene (FLU), phenanthrene (PHE), anthracene (ANT), pyrene (PYR), chrysene (CHR), and benzo(a)pyrene (BaP)) in the model soil; noticeably, 84.5% and 96.7% of initial PYR and BaP were degraded, respectively. In the MGP soil, the same treatment destroyed more than 80% of 2- and 3-ring hydrocarbons and 20-40% of 4- and 5-ring compounds. However, the low pH requirement (pH 2-3) for optimum Fenton reaction made the process incompatible with biological treatment and posed potential hazards to the soil ecosystem where the reagent was used. In order to overcome such limitation, a modified Fenton-type reaction was performed at near neutral pH by using ferric ions and chelating agents such as catechol and gallic acid. By the combined treatment of the modified Fenton reaction and biodegradation, more than 98% of 2- or 3-ring hydrocarbons and between 70% and 85% of 4- or 5-ring compounds were degraded in the MGP soil, while maintaining its pH about 6-6.5.