Roland W. Scholz

Engineered nanomaterials (ENM) are already used in many products and consequently released into environmental compartments. In this study, we calculated predicted environmental concentrations (PEC) based on a probabilistic material flow analysis from a life-cycle perspective of ENM-containing products. We modeled nano-TiO(2), nano-ZnO, nano-Ag, carbon nanotubes (CNT), and fullerenes for the U.S., Europe and Switzerland. The environmental concentrations were calculated as probabilistic density functions and were compared to data from ecotoxicological studies. The simulated modes (most frequent values) range from 0.003 ng L(-1) (fullerenes) to 21 ng L(-1) (nano-TiO(2)) for surface waters and from 4 ng L(-1) (fullerenes) to 4 microg L(-1) (nano-TiO(2)) for sewage treatment effluents. For Europe and the U.S., the annual increase of ENMs on sludge-treated soil ranges from 1 ng kg(-1) for fullerenes to 89 microg kg(-1) for nano-TiO(2). The results of this study indicate that risks to aquatic organisms may currently emanate from nano-Ag, nano-TiO(2), and nano-ZnO in sewage treatment effluents for all considered regions and for nano-Ag in surface waters. For the other environmental compartments for which ecotoxicological data were available, no risks to organisms are presently expected.

Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.

Purpose The goal of this paper is to enhance consideration for the potential for institutions of higher education throughout the world, in different cultures and contexts, to be change agents for sustainability. As society faces unprecedented and increasingly urgent challenges associated with accelerating environmental change, resource scarcity, increasing inequality and injustice, as well as rapid technological change, new opportunities for higher education are emerging. Design/methodology/approach The paper builds on the emerging literature on transition management and identifies five critical issues to be considered in assessing the potential for higher education as a change agent in any particular region or place. To demonstrate the value of these critical issues, exemplary challenges and opportunities in different contexts are provided. Findings The five critical issues include regional‐specific dominant sustainability challenges, financing structure and independence, institutional organization, the extent of democratic processes, and communication and interaction with society. Originality/value Given that the challenges and opportunities for higher education as a change agent are context‐specific, identifying, synthesizing, and integrating common themes is a valuable and unique contribution.

Microsomes from rat liver form hydrogen peroxide in the presence of an NADPH‐generating system in proportion to protein concentrations as determined by three independent methods: ferrithiocyanate, cytochrome c peroxidase, and scopoletin fluorescence. Maximal rates observed were about 15 μmol H 2 O 2 /g microsomal protein per minute. The oxygen concentration for half‐maximal rates was 50 μM. It is suggested that NADPH‐dependent hydrogen peroxide formation in microsomes is mainly due to NADPH oxidase; however, partial inhibition by carbon monoxide suggests that about one third arises from the autoxidation of cytochrome P‐450. Similarities exist between microsomal acetaldehyde production from ethanol ( i.e. the microsomal ethanol‐oxidizing system of Lieber and DeCarli [4]) and hydrogen peroxide formation: viz. requirement for NADPH and oxygen, identical oxygen concentrations for halfmaximal rates, and sensitivity to carbon monoxide. Microsomal acetaldehyde production in the presence of either an NADPH‐ or an H 2 O 2 ‐generating system exhibits identical characteristics as follows: (a) ethanol concentration for half‐maximal rates ( i.e. 12 mM); (b) dependency of maximal rates on rates of hydrogen peroxide formation; (c) competitive inhibition by peroxidatic substrates for catalase, e.g. formate (half‐maximal effect: 150 μM); (d) inhibition by catalase inhibitors, e.g. azide (half‐maximal effect: 50 μM), with identical azide insensitive rates; (e) diminished acetaldehyde production in microsomes from rats pretreated with aminotriazole or pyrazole with identical residual rates. Moreover, NADPH‐dependent acetaldehyde production is suppressed in the presence of an active H 2 O 2 ‐utilizing system. Thus, it is concluded that the NADPH‐dependent microsomal ethanol‐oxidizing system of Lieber and DeCarli [4] is due to a hydrogen peroxide formation from NADPH and a subsequent peroxidation of ethanol by contaminating catalase. The data indicate that the existence of a unique system in addition to the peroxidatic reaction of catalase as postulated recently [4] is highly doubtful.