Ion Electron–Coupled Functionality in Materials and Devices Based on Conjugated Polymers

The coupling between charge accumulation in a conjugated polymer and the ionic charge compensation, provided from an electrolyte, defines the mode of operation in a vast array of different organic electrochemical devices. The most explored mixed organic ion–electron conductor, serving as the active electrode in these devices, is poly(3,4‐ethyelenedioxythiophene) doped with polystyrelensulfonate (PEDOT:PSS). In this progress report, scientists of the Laboratory of Organic Electronics at Linköping University review some of the achievements derived over the last two decades in the field of organic electrochemical devices, in particular including PEDOT:PSS as the active material. The recently established understanding of the volumetric capacitance and the mixed ion–electron charge transport properties of PEDOT are described along with examples of various devices and phenomena utilizing this ion–electron coupling, such as the organic electrochemical transistor, ionic–electronic thermodiffusion, electrochromic devices, surface switches, and more. One of the pioneers in this exciting research field is Prof. Olle Inganäs and the authors of this progress report wish to celebrate and acknowledge all the fantastic achievements and inspiration accomplished by Prof. Inganäs all since 1981.     

Haloacetic acids in drinking water in the United Kingdom

We measured concentrations of haloacetic acids (HAAs) in the water supply in regions covered by three water companies in the UK Approximately 30 samples in each region were obtained for analysis of both THMs and HAAs to assess the levels of HAAs and the relationship between HAAs and THMs, temperature, pH, free and total chlorine. We have found that there is a range of HAA levels in drinking water with the means ranging from 35-95mug/l and a maximum concentration of 244mug/l. In two out of the three regions there was a high correlation between total THMs and total HAAs, but whereas the HAA and THM levels in one of these companies were approximately equal, in another company the HAA levels were 3-4 times higher than the THM levels. In the third region there was no correlation between total THMs and total HAAs even though the average levels were approximately equal. The ratio of total THM and total HAAs levels was significantly correlated with temperature, pH, free and total chlorine. Overall total THM levels are therefore not considered to be a good indicator of HAA levels. Epidemiological studies using total THM levels should be taking this into account in the interpretation of their results, and regulatory authorities when setting water guidelines.     

Sulfide removal in wastewater from petrochemical industries by autotrophic denitrification

An alternative flowchart for the biological removal of hydrogen sulfide from oil-refining wastewater is presented; autotrophic denitrification in a multi-stage treatment plant was utilized. A pilot-scale plant was fed with a mixture of the following constituents: (a) original wastewater from an oil refining industry (b), the effluent of the existing nitrification-stage treatment plant and (c) sulfide in the form of Na2S. Anoxic sulfide to sulfate oxidation, with nitrate as a terminal electron acceptor, proved very successful, as incoming concentrations of 110 mg S2-/L were totally converted to SO(4)2-. At complete denitrification, the concentration of S2- in the reactor effluent was less than 0.1mg/L. Fluctuating S2- concentration in the feed could be tolerated without any problems, as the accumulated sulfide in the effluent of the denitrification stage is oxidized aerobically in a subsequent activated-sludge treatment stage. This alternative new treatment scheme was further introduced at the refinery's wastewater processing plant. Thus, complete H2S removal is now accomplished by the combination of the proposed biological method and the existing stripping with CO2. As a result, stripping, and thus its cost, is reduced by 70%.     

f-Value: measuring an article’s scientific impact

The f-value is a new indicator that measures the importance of a research article by taking into account all citations received, directly and indirectly, up to depth n. The f-value considers all information present in a Citation Graph in order to produce a ranking of the articles. Apart from the mathematical equation that calculates the f-value, we also present the corresponding algorithm with its implementation, plus an experimental comparison of f-value with two known indicators of an article’s scientific importance, namely, the number of citations and the Page Rank for citation analysis. Finally, we discuss the similarities and differences among the indicators.     

Importance of carbon surface chemistry in development of iron-carbon composite adsorbents for arsenate removal

Micro/mesoporous activated carbon was oxidized and used either as received or after modification as a support for the deposition of iron oxyhydroxide. The prepared samples were applied as adsorbents of arsenate from water phase. The initial materials and those after adsorption were characterized using adsorption of nitrogen, - potentiometric titration, FTIR, EDX, XRD, AAS, and thermal analysis. The results obtained suggest that oxidation of the carbon support increases significantly the amount of iron oxyhydroxide species deposited on the surface and thus decreases their dispersions and the efficiency of arsenate immobilization in the carbon pore system. Iron hydroxyoxides react with arsenate forming salts. Moreover, a meso/microporous carbon surface contributes to changes in the toxicity of arsenic via reduction of As(V) to As(III). This is visible in the increased degree of carbon oxidation.     

Deciphering the Epigenetic Alphabet Involved in Transgenerational Stress Memory in Crops

Although epigenetic modifications have been intensely investigated over the last decade due to their role in crop adaptation to rapid climate change, it is unclear which epigenetic changes are heritable and therefore transmitted to their progeny. The identification of epigenetic marks that are transmitted to the next generations is of primary importance for their use in breeding and for the development of new cultivars with a broad-spectrum of tolerance/resistance to abiotic and biotic stresses. In this review, we discuss general aspects of plant responses to environmental stresses and provide an overview of recent findings on the role of transgenerational epigenetic modifications in crops. In addition, we take the opportunity to describe the aims of EPI-CATCH, an international COST action consortium composed by researchers from 28 countries. The aim of this COST action launched in 2020 is: (1) to define standardized pipelines and methods used in the study of epigenetic mechanisms in plants, (2) update, share, and exchange findings in epigenetic responses to environmental stresses in plants, (3) develop new concepts and frontiers in plant epigenetics and epigenomics, (4) enhance dissemination, communication, and transfer of knowledge in plant epigenetics and epigenomics.     

Effect of water activity on the thermal stability of Thermomyces lanuginosus xylanases for process time–temperature integration

Three strains of the thermophilic fungus Thermomyces lanuginosus were used to produce β-xylanases. The thermal stability of these xylanases at low levels of water activity was studied. Isothermal inactivation experiments were performed in the temperature range of 100–130 °C. Reduction of water activity to 0.63 and as low as 0.13 had a drastic effect on the observed D and z-values. At water activity of 0.13 the D_120 °C and z-values of the three xylanases ranged from 20.4 to 37.6 min and from 23.3 to 28.9 °C, respectively. The applicability of the developed kinetic models was tested under time–temperature profiles representative of typical thermal processes. The developed systems can be applied as time–temperature integrators (TTI) at this high thermal processing range. Calculations demonstrated that the use of a triple xylanase TTI system could provide acceptable F-values prediction for z-values lower than the achieved range.     

On the importance of total polar phenols to monitor the stability of Greek virgin olive oil

A large number of virgin olive oil samples obtained from different areas in Greece were analyzed for various quality parameters. The work focuses on the colorimetric determination of total phenols with the Folin‐Ciocalteu reagent and its importance in predicting shelf life of virgin olive oil. The results indicate a good correlation of total polar phenol content with the stability of the oil. Colorimetric determination of ortho‐diphenol content does not seem to be a better means for predicting virgin olive oil stability. RP‐HPLC quantification of hydroxytyrosol and tyrosol in their free form gives poor results in the case of freshly extracted oils. It is concluded that until an easy‐to‐manage HPLC method will be available, which will quantify accurately both free and bound forms of hydroxytyrosol and other phenolics, the colorimetric method for the determination of total polar phenols remains a good practical means to evaluate the stability of virgin olive oil.     

Chain extension of recycled poly(ethylene terephthalate) with 2,2′‐(1,4‐phenylene)bis(2‐oxazoline)

The present work provides improved recycled high molecular weight poly(ethylene terephthalate) (PET) by chain extension using 2,2′‐(1,4‐phenylene)bis(2‐oxazoline) (PBO) as the chain extender. PBO is a very reactive compound toward macromolecules containing carboxyl end groups but not hydroxyl end groups. In the case of PET, where both species are present, for even better results, phthalic anhydride (PA) was added in the initial sample, before the addition of PBO. With this technique, we succeeded in increasing the carboxyl groups by reacting PA with the hydroxyl terminals of the starting polymer. From this modification of the initial PET sample, PBO was proved an even more effective chain extender. So, starting from a recycled PET with intrinsic viscosity [η] = 0.78, which would be [η] = 0.69 after the aforementioned treatment without a chain extender or M̄_n = 19,800, we prepared a PET grade having [η] = 0.85 or M̄_n = 25,600 within about 5 min. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2206–2211, 2000