Photocatalytic and Photochemical Oxidation of Ethylene: Potential for Storage of Fresh Produce—a Review

The phytohormone ethylene exerts numerous beneficial and detrimental effects on postharvest quality and storage life of fruit and vegetables. In view of the current global challenge of reducing postharvest losses and waste of fruit and vegetables, the importance of ethylene management in the supply chain is paramount. For this purpose, various methods have been applied along the supply chain over the years; however, effective management of ethylene under real-time storage and transport conditions still remains a challenging task. This review explores the potential of photocatalytic and photochemical oxidation of ethylene for effective removal of this gas along the value chain of fruit and vegetables. These techniques involve the use of ultraviolet (UV) radiation with or without a catalyst. In photocatalytic oxidation, a semiconductor such as titanium dioxide is essential which acts as a photocatalyst on irradiation with UV light and thus facilitates the oxidation of ethylene at its surface, whereas in photochemical oxidation, extreme short wave (i.e. below 200 nm) vacuum ultraviolet radiation (VUV) consisting of high-energy photons eliminates ethylene in the gaseous state. This review gives a brief overview of current commercial techniques used in ethylene removal and then focuses on the photocatalytic and the photochemical oxidation of ethylene and the combination of both methods. The various factors affecting these processes are also discussed including the advantages and the drawbacks associated with them, and current applications of these methods in fruit and vegetable storage systems are highlighted. In addition, a future outlook on the application of these methods in postharvest storage of fresh produce is given.     

Manufacture and characterization of optical coatings with incorporated copper island films

Copper island films have been prepared by thermal evaporation in vacuum and characterized by in situ as well as ex situ spectrophotometry. The parallel investigation of the island morphology by means of transmission electron microscopy allowed us to establish a clear correlation between film structure and optical properties. The effective optical constants of the copper island films could be determined by means of a fit of their ex situ transmission and reflection spectra. The effective optical constants have been used for designing and preparing optical multilayer coatings applicable for attenuator or color filter specifications. Measured characteristics of the multilayer coatings are in very good agreement with the calculated spectra.     

Why there is universality in rationality.

Rationality or reason, traditionally conceived as a universal, essential human faculty, is out of favor these days. Its defenders are few, compared to its many challengers. The challengers are not those who lament the decline of reason but rather those who express an egalitarian impulse, in their determination to refute universal, essential ideals of reason. These challengers are a diverse lot and sometimes prefer to speak instead of “rationalities” (in the plural), or what Shweder (1986) called “divergent rationalities.” This paper considers the question whether this trend toward divergent rationalities is itself reasonable. To answer this question, the paper begins with some standard definitions of rationality or reason, on the understanding that any such standard is what stands in question. This is followed by recent work of Evnine (2008) that demonstrates just how our personhood logically entails universal epistemic “dimensions,” some of which are normative, rational dimensions. Evidence that Nisbett (2003) and Shweder (1986) muster to challenge a universal rationality is then considered, ending with a defense of just that which is challenged. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transmuting performance on manufacturing dimensions into business performance: An exploratory analysis of efficiency using DEA

This research examines efficiency in the transformation of performance on manufacturing competitive dimensions into business performance in the automotive supplier industry. Specifically, the study explores efficiency produced from data envelopment analysis (DEA) using cost, quality, time, flexibility and innovativeness performance as inputs and return on investment (ROI) and return on assets (ROA) as outputs. First tier suppliers to the 'Big 3' in North America were sampled. The 51 suppliers were categorized into three groups (high, medium and low) based on their efficiency. No significant group differences in quality, time, flexibility and innovativeness performance were found, but a significant difference does exist for cost. The results were further investigated by testing between-group differences for various cost reduction programmes, thereby identifying the levers and benchmarks for improving low efficiency firms.     

Thioarsenate transformation by filamentous microbial mats thriving in an alkaline, sulfidic hot spring

Thioarsenates dominate arsenic speciation in sulfidic geothermal waters, yet little is known about their fate in the environment. At Conch Spring, an alkaline hot spring in Yellowstone National Park, trithioarsenate transforms to arsenate under increasingly oxidizing conditions along the drainage channel, accompanied by an initial increase, then decrease of monothioarsenate and arsenite. On-site incubation tests were conducted using sterile-filtered water with and without addition of filamentous microbial mats from the drainage channel to distinguish the role of abiotic and biotic processes for arsenic species transformation. Abiotically, trithioarsenate was desulfidized to arsenate coupled to sulfide oxidation. Monothioarsenate, however, was inert. Biotic incubations proved that the intermediate accumulation of arsenite in the drainage channel is microbially catalyzed. In the presence of sulfide, microbially enhanced sulfide oxidation coupled to reduction of arsenate to arsenite could simply enhance abiotic desulfidation of trithioarsenate and potentially also monothioarsenate. However, we were also able to show, in sulfide-free medium, direct microbial transformation of monothioarsenate to arsenate. Some arsenite formed intermediately, which was subsequently also microbially oxidized to arsenate. This study is the first evidence for microbially mediated thioarsenate species transformation by (hyper)thermophilic prokaryotes.     

Reinigbarkeit von Oberflächen in der Lebensmittelindustrie durch Flüssigkeitsstrahlen

The influence of properties of product contact surfaces on cleanability is widely discussed in the food processing and pharmaceutical industry. In the present work stainless steel surfaces of different surface roughness, surface energy and electrokinetic properties were subject to organic soiling in order to study the influence of surface properties on cleanability. As food model test soils gelatinized starch and whey protein were chosen. The cleaning was realized by means of water jets from a flat fan nozzle.