Search

City morphology not only reveals spatial distribution of diverse physical parameters but also of diverse socio-economic characteristics. Because of this, spatial structure or zoning in urban spaces is a key variable for inferring information valuable for assessment, planning, and management purposes. The presented methodology shows a mathematical approach to derive homogeneous zones from a solely remote sensing land-cover classification result. By Savitzky-Golay filtering and a subsequent curve-sketching approach, an interpreter-independent differentiation within a city is computed. The classification shows the result of the arrangement of urban zoning without any ancillary data [ABSTRACT FROM PUBLISHER]

High resolution imaging spectroscopy data have been recognised as a valuable data resource for augmenting detailed material inventories that serve as input for various urban applications. Image-specific urban spectral libraries are successfully used in urban imaging spectroscopy studies. However, the regional- and sensor-specific transferability of such libraries is limited due to the wide range of different surface materials. With the developed methodology, incomplete urban spectral libraries can be utilised by assuming that unknown surface material spectra are dissimilar to the known spectra in a basic spectral library (BSL). The similarity measure SID-SCA (Spectral Information Divergence-Spectral Correlation Angle) is applied to detect image-specific unknown urban surfaces while avoiding spectral mixtures. These detected unknown materials are categorised into distinct and identifiable material classes based on their spectral and spatial metrics. Experimental results demonstrate a successful redetection of material classes that had been previously erased in order to simulate an incomplete BSL. Additionally, completely new materials e.g., solar panels were identified in the data. It is further shown that the level of incompleteness of the BSL and the defined dissimilarity threshold are decisive for the detection of unknown material classes and the degree of spectral intra-class variability. A detailed accuracy assessment of the pre-classification results, aiming to separate natural and artificial materials, demonstrates spectral confusions between spectrally similar materials utilizing SID-SCA. However, most spectral confusions occur between natural or artificial materials which are not affecting the overall aim. The dissimilarity analysis overcomes the limitations of working with incomplete urban spectral libraries and enables the generation of image-specific training databases., Competing Interests: The authors declare no conflict of interest.

In genetic toxicology, risk assessment has traditionally adopted linear dose-responses for any compound that causes genotoxic effects. Increasing evidence of non-linear dose-responses, however, suggests potential cellular tolerance to low levels of many genotoxicants with diverse modes of action. Such putative non-linear dose-responses need to be substantiated by strong mechanistic data that identifies the mechanisms responsible for the tolerance to low doses. This can be achieved by experimental demonstration of cytoprotective mechanisms and by providing experimental support for the existence of tolerance mechanisms against low dose effects. By highlighting key experiments into low dose mechanisms, this review aims to clarify which mechanistic data are required to support the use of non-linear dose-response models in risk assessment. Such key experiments are presented and discussed for alkylating agents, oxidants, particulate matter, nucleoside analogues, topoisomerase inhibitors and aneugens and exemplify the use of gene knockout models or transgenic models as well as chemical modulators of key effectors of relevant pathways and their impact on dose-response relationships. In vitro studies are particularly valuable to elucidate mechanisms of low-dose protection or lack thereof, while in vivo experiments are most appropriate for deriving a safe dose. In order to evaluate the existence of non-linear dose-response relationships for genotoxicants, we suggest that careful attention should be given to the mode of genotoxic action, relevant biomarkers of exposure, as well as to the existence and impact of potential cytoprotective mechanisms like detoxifying metabolism and DNA repair., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Nitrate is a natural constituent of the human diet and an approved food additive. It can be partially converted to nitrogen monoxide, which induces vasodilation and thereby decreases blood pressure. This effect is associated with a reduced risk regarding cardiovascular disease, myocardial infarction, and stroke. Moreover, dietary nitrate has been associated with beneficial effects in patients with gastric ulcer, renal failure, or metabolic syndrome. Recent studies indicate that such beneficial health effects due to dietary nitrate may be achievable at intake levels resulting from the daily consumption of nitrate-rich vegetables. N-nitroso compounds are endogenously formed in humans. However, their relevance for human health has not been adequately explored up to now. Nitrate and nitrite are per se not carcinogenic, but under conditions that result in endogenous nitrosation, it cannot be excluded that ingested nitrate and nitrite may lead to an increased cancer risk and may probably be carcinogenic to humans. In this review, the known beneficial and detrimental health effects related to dietary nitrate/nitrite intake are described and the identified gaps in knowledge as well as the research needs required to perform a reliable benefit/risk assessment in terms of long-term human health consequences due to dietary nitrate/nitrite intake are presented., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

3',5'-Cyclic AMP (cAMP) is one of the most important second messengers in mammalian cells, mediating a multitude of diverse cellular signalling responses. Its homeostasis is primarily regulated by adenylate cyclases and phosphodiesterases (PDE), the activities of which are partially dependent on the downstream events of adenosine receptor signalling. The present study was conducted to determine whether coffee constituents other than caffeine can influence the homeostasis of intracellular cAMP in vitro and in vivo by evaluating the effects of selected constituents present in coffee, coffee brews and coffee extracts on platelet PDE activity. In addition, to evaluate the potential effects of these constituents on platelet cAMP concentrations and PDE activity in humans, a 7-week pilot intervention study with eight subjects was conducted. The subjects consumed a regular commercial coffee and a low-caffeine coffee at a rate of 750 ml/d for 2 weeks each. The in vivo results revealed a highly significant inhibition of PDE activity (P< 0·001) after coffee intervention that was not directly dependent on the caffeine content of coffee. Although our in vitro and in vivo findings suggest that caffeine plays some role in the modulation of platelet cAMP status, other natural and roasting-associated compounds such as pyrazines and other currently unidentified species also appear to contribute significantly. In conclusion, moderate consumption of coffee can modulate platelet PDE activity and cAMP concentrations in humans, which may contribute to the putative beneficial health effects of coffee. Further detailed mechanistic investigations will be required to substantiate these beneficial effects and to elucidate the underlying mechanisms.

α,β-Unsaturated aliphatic carbonyl compounds are naturally widespread in food, but are also formed during the thermal treatment of food. This applies, for example, to the genotoxic carcinogen acrylamide (AA), but also to acrolein (AC), the simplest α,β-unsaturated aldehyde. First observations indicate that human exposure to AC may be higher than the exposure to AA. The DFG Senate Commission on Food Safety therefore compared data on AC and AA available in the scientific literature, evaluating current knowledge on formation, occurrence, exposure, metabolism, biological effects, toxicity, and carcinogenicity and defined knowledge gaps as well as research needs in an opinion on November 19, 2012, in German. The English version was agreed on April 17, 2013., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Acrylamide (AA), classified as class 2A carcinogen (probably carcinogenic to humans) by the International Agency for Research on Cancer (IARC), is formed during heating of food from reducing carbohydrates and asparagine by Maillard reaction chemistry. After dietary uptake, AA is in part metabolically converted into the proximate genotoxic phase I metabolite glycidamide (GA). GA reacts with nucleophilic base positions in DNA, primarily forming N7-(2-carbamoyl-2-hydroxyethyl)guanine (N7-GA-Gua) adducts. In a competing phase II biotransformation pathway AA, as well as its phase I metabolite GA, is coupled to glutathione (GSH). The GSH coupling products are further biotransformed and excreted via urine as mercapturic acids (MA), N-acetyl-S-(2-carbamoylethyl)cysteine (AAMA), and N-acetyl-S-(2-hydroxy-2-carbamoylethyl)cysteine (GAMA). In the present study, hepatic biotransformation pathways and DNA adduct formation were studied in primary rat hepatocytes, incubated with AA (0.2-2,000 μM) for up to 24 h. Contents of AA-GSH, GA, AAMA, and GAMA were measured in the cell culture medium after solid phase extraction (SPE). N7-GA-Gua adducts in DNA of hepatocytes were determined by HPLC-ESI-MS/MS after lysis of the cells and neutral thermal hydrolysis. Formation of AA-GSH was linear with AA concentration and incubation time and became detectable already at 0.2 μM (4 h). In contrast to AA, GA was not detected before 16 h incubation at 10-fold higher AA concentration (2 μM). In summary, the rate of AA-GSH formation was found to be about 1.5-3 times higher than that of GA formation. N7-GA-Gua adducts were found only at the highest AA concentration tested (2,000 μM).

The working group "Food technology and safety" of the DFG Senate Commission on Food Safety (SKLM) advises on new technologies concerning food processing. Treatment with plasma is a newly developed process, which is currently used only on a pilot scale in Europe. The novel plasma treatment technology is experimentally applied to consumer goods. There are also potential applications in the food sector, e.g. to inactivate microorganisms on food surfaces. There is still insufficient information on concomitant physical and chemical processes and changes induced in the food. On May 25th 2012, the SKLM issued a first statement on plasma treatment of foods in German. The English version was agreed on December 14th 2012., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The plant alkaloid lycobetaine has potent topoisomerase-targeting properties and shows anticancer activity. Based on these findings, several lycobetaine analogs were synthesized mainly differing in their substituents at 2, 8 and 9 position and their biological activities were evaluated. The topoisomerase-targeting properties and cytotoxicity of these structural analogs were assessed in the human gastric carcinoma cell line GXF251L. Performing a plasmid relaxation assay, an increased inhibition of topoisomerase I was found with N-methylphenanthridinium chlorides bearing a 8,9-methylenedioxy moiety or a methoxy group in 2-position. Furthermore, quaternized phenanthridinium derivatives bearing either a 2-methoxy or a 8,9-methylenedioxy moiety in conjunction with a 2-hydroxy or 2-methoxy group display potent topoisomerase II inhibition as shown by decatenation of kinetoplast DNA. In general, the N-methylphenanthridinium chlorides possess more potency in inhibiting topoisomerase I than topoisomerase II. All quaternized derivatives also exhibited potent inhibition of tumor cell growth in the low micromolar concentration range. Hence, N-methylphenanthridinium compounds were found to represent a promising class of compounds, potently inhibiting both, topoisomerases I and II, and may be further developed into clinically useful topoisomerase inhibitors., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The Council of the European Union has proposed a revision on the EU regulation on novel foods and novel food ingredients concerning safety assessment of traditional foods from non-EU countries and their introduction onto the EU market. The proposal stipulates that such foods may be placed on the EU market if their history of safe use in the country of origin is appropriately documented. The present statement of the SKLM gives an overview on current discussions on practical implementation of the "history of safe use" concept as well as examples of its application. The SKLM, in principle, agrees with these concepts, underscores, however, in connection with convincing evidence for a "history of safe use" the need for a range of additional information to achieve a comprehensive risk assessment. In the opinion of the SKLM such information must comprise compositional data as well as experience on adverse effects. A list of questions considered essential is presented. The following opinion was adopted on December 23rd 2010., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The DFG Senate Commission on Food Safety (SKLM) has discussed the toxicological assessment of furanocoumarins in foodstuffs and adopted an opinion on 23/24 September 2004 [SKLM, English version: Toxicological assessment of furanocumarins in foodstuffs, 2006; Mol. Nutr. Food Res. 2007, 51, 367-373]. At that time, no analytical data were available on the occurrence and content of furanocoumarins in citrus oils, especially in lime oil and the foodstuffs produced from it. According to the SKLM, the highest levels were likely to be found in products containing lime or bergamot oil. Distilled and cold pressed oils differ in their levels of furanocoumarins; in distilled oils, no furanocoumarins were found. The original estimate of the average daily intake of furanocoumarins in Germany made by the SKLM is based on the assumption that flavoured foods contain cold-pressed citrus oils exclusively (worst case scenario). Recent data, however, indicate that distilled citrus oils are mainly used in flavoured soft drinks. The SKLM has therefore decided to update the assessment of the average intake of furanocoumarins from flavoured food. The following opinion was released in German on 25 January 2010, the English version was agreed on 27/28 September 2010., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)