bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence of Functional Group Orientation on the Structure of Zinc 1,1,4‐Trimethylthiosemicarbazide Dicarboxylates: Probing the Limits of Crystal Engineering Strategies
Authors: Burrows Andrew D. , Harrington Ross W. , Mahon Mary F. , Teat Simon J. 
Published: February 2003

AbstractThe reaction of [Zn(tmtsc)2](NO3)2 [tmtsc = 1,1,4‐trimethylthiosemicarbazide, MeNHC(S)NHNMe2] with a range of sodium dicarboxylates has been shown to lie on the borderline between commonly used crystal engineering strategies. The products exhibit a wide range of structural diversity with the main driving force being the relative orientation of the carboxylate groups. Thus, fumarate leads to the hydrogen‐bonded aggregate [Zn(tmtsc)2(OH2)][fumarate] (2) in which cations and anions are linked by hydrogen bond donor‐donor acceptor‐acceptor (DD:AA) interactions, whereas isophthalate and (+)‐camphorate lead to coordination polymers [Zn(tmtsc)(μ‐isophthalate)] (3a) and [Zn(tmtsc)(μ‐camphorate)] (4) with the metal centres linked by bridging dicarboxylate ligands. In the case of isophthalate, a hydrated product [Zn(tmtsc)(μ‐isophthalate)]·H2O (3b) was also characterised, although microanalysis and powder X‐ray diffraction revealed this to be a minor product. Incorporation of water was shown to lead to a change in carboxylate coordination mode from η1 in 3a to η2 in 3b. Use of terephthalate leads to the compound [{Zn(tmtsc)(OH2)}2(μ‐terephthalate)][terephthalate]·2H2O (5), in which half of the terephthalates bridge metal centres, to form dimers, and the remainder link the dimeric cations through DD:AA hydrogen bond interactions. Homophthalate leads to discrete dimers [Zn(tmtsc)(μ‐homophthalate)]2 (6), whereas acetylenedicarboxylate yields the unexpected compound [Zn(tmtsc)2(OH2)][O2CCH=CC(O)N(Me)C(=NNMe2)S]2·H2O (7) in which the dicarboxylate has reacted with tmtsc to give a 2‐hydrazono‐4‐oxo‐1,3‐thiazolidineacetate, which is subsequently trapped in the solid state by DD:AA hydrogen bonding interactions with [Zn(tmtsc)2(OH2)]2+. All products were characterised by single crystal X‐ray crystallography, and the representational nature of these crystal structures to the bulk materials was confirmed by microanalysis and powder diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Consequences of forest fires on the hydrogeological response of mountain catchments: a case study of the Riale Buffaga, Ticino, Switzerland
Authors: Conedera Marco , Peter Larissa , Marxer Peter , Forster Felix , Rickenmann Dieter , Re Lorenza 
Published: February 2003

AbstractThe debris flow of 28 August 1997 which occurred in the Riale Buffaga, a torrent channel in the territory of the village of Ronco s./Ascona (Ticino, Switzerland), has been simulated with a good degree of reliability due to the existence of morphologic surveys of the torrent channel preceding the flood event and the presence of a rain gauge that registered the rainfall event at a resolution of 10 minutes. With these data it is possible to conduct a quantitative analysis of the effect of a forest fire on the hydrogeological response of a given catchment. In the case at hand, a 10‐year rainfall event caused a 100‐ to 200‐year flood event. This result clearly quantifies the possible consequences of a forest fire in terms of territorial safety. Copyright © 2003 John Wiley & Sons, Ltd.
Modelling the effect of vegetation on channel pattern in bedload rivers
Authors: Murray A. Brad , Paola Chris 
Published: February 2003

AbstractWe modify a simple numerical stream‐pattern model to examine the effect of sediment stabilization by roots on the channel pattern of bedload rivers. In the model, vegetation enhances bank resistance to erosion, causing the development of a single channel instead of a rapidly changing, multiple channel (braided) pattern. Net aggradation resulting from a high sediment supply, however, causes frequent avulsions that destroy vegetation locally, leading to the development of a multiple‐channel pattern. A stability diagram representing multiple model runs predicts whether a river will exhibit single or multiple channels, based on plant‐enhanced bank strength, and on the time scale of plant development relative to a time scale for change in unvegetated channels. A second stability diagram predicts the way in which the amplitude and period of a fluctuating imposed sediment load influence whether a single or multiple‐channel pattern develops. Copyright © 2003 John Wiley & Sons, Ltd.
Deforestation of water‐repellent soils in Galicia (NW Spain): effects on surface runoff and erosion under simulated rainfall
Authors: Benito E. , Santiago J.L. , de Blas E. , Varela M.E. 
Published: February 2003

AbstractAt three adjacent sites in steeply sloping woodland in Galicia (NW Spain), surface runoff and associated erosion under simulated rainfall (64 mm h−1) were measured on five occasions between June 1998 and July 1999. Two of the three sites had recently been deforested and topsoil added, and one of these two had been sown with grass, which was germinating at the onset of the study. Deforestation greatly increased runoff and erosion rates, and the recovery of plant cover reduced erosion. All three soils were very hydrophobic due to high levels of poorly humified organic matter, which led to higher runoff rates than expected, especially during dry periods. However, great structural stability prevented there being a significant correlation between runoff rate and soil erosion. Copyright © 2003 John Wiley & Sons, Ltd.
The influence of bedrock‐derived acidity in the development of surface and underground karst: evidence from the Precambrian carbonates of semi‐arid northeastern Brazil
Authors: Auler Augusto S. , Smart Peter L. 
Published: February 2003

AbstractVery extensive cave systems are developed in Precambrian Una Group carbonates in the Campo Formoso area, eastern Brazil. In contrast, the area is largely devoid of significant surface karst landforms, as would be expected given its semi‐arid climate. The caves in the area display many morphological features characteristic of deep‐seated hypogenic caves, such as lack of relationship with the surface, ramiform/network pattern, abrupt variations of passage cross‐sections and absence of fluvial sediments, but do not show evidence of vertical passages marking the ascending path of acidic water nor present extensive gypsum or acid clay mineral deposits. Hydrochemical analyses of present‐day ground water indicate that oxidation of bedrock sulphide is an active process, and sulphuric acid may be the main agent driving carbonate dissolution in the area. A shallow mode of speleogenesis is thus proposed, in which sulphuric acid produced through the oxidation of sulphide beds within the carbonates controls cave initiation and development. Moreover, the geological situation of the area in an ancient stable passive margin precludes the possibility of deep‐seated sources of acidity.Under dry climate, due to the absence of recharge, solutional landforms will be largely subdued in the surface. Hypogenic processes, if present, are likely to predominate, producing a landscape characterized by a marked disparity in the comparative degree of development between surface and underground landforms. Rates of karst landform development have traditionally been analysed through a climatic perspective, runoff being the main controlling factor in promoting karst development. This view needs to be reassessed in the light of the growing awareness of the importance of climate‐independent processes related to hypogenic sources of acidity. Copyright © 2003 John Wiley & Sons, Ltd.
Calcrete profile development in Quaternary alluvial sequences, southeast Spain: implications for using calcretes as a basis for landform chronologies
Authors: Candy Ian , Black Stuart , Sellwood Bruce W. , Rowan John S. 
Published: February 2003

AbstractA detailed study of the morphology and micro‐morphology of Quaternary alluvial calcrete profiles from the Sorbas Basin shows that calcretes may be morphologically simple or complex. The ‘simple’ profiles reflect pedogenesis occurring after alluvial terrace formation and consist of a single pedogenic horizon near the land surface. The ‘complex’ profiles reflect the occurrence of multiple calcrete events during terrace sediment aggradation and further periods of pedogenesis after terrace formation. These ‘complex’ calcrete profiles are consequently described as composite profiles. The exact morphology of the composite profiles depends upon: (1) the number of calcrete‐forming events occurring during terrace sediment aggradation; (2) the amount of sediment accretion that occurs between each period of calcrete formation; and (3) the degree of pedogenesis after terrace formation. Simple calcrete profiles are most useful in establishing landform chronologies because they represent a single phase of pedogenesis after terrace formation. Composite profiles are more problematic. Pedogenic calcretes that form within them may inherit carbonate from calcrete horizons occurring lower down in the terrace sediments. In addition erosion may lead to the exhumation of older calcretes within the terrace sediment. Calcrete ‘inheritance’ may make pedogenic horizons appear more mature than they actually are and produce horizons containing carbonate embracing a range of ages. Calcrete exhumation exposes calcrete horizons whose morphology and radiometric ages are wholly unrelated to terrace surface age. Composite profiles are, therefore, only suitable for chronological studies if the pedogenic horizon capping the terrace sequence can be clearly distinguished from earlier calcrete‐forming events. Thus, a detailed morphological/micro‐morphological study is required before any chronological study is undertaken. This is the only way to establish whether particular calcrete profiles are suitable for dating purposes. Copyright © 2003 John Wiley & Sons, Ltd.
A process‐based conversion model for caesium‐137 derived erosion rates on agricultural land: an integrated spatial approach
Authors: Van Oost K. , Govers G. , Van Muysen W. 
Published: February 2003

AbstractThere is increasing recognition that 137Cs data remain one of the few sources of spatially distributed information concerning soil erosion. However, many of the conversion models that have been used to convert 137Cs data into soil redistribution rates failed to account for some of the key factors affecting the redistribution of 137Cs in agricultural landscapes. The conversion model presented in this paper aims to overcome some of the limitations associated with existing models and therefore to provide more realistic estimates of soil erosion rates on agricultural land. The conversion model aims at coupling soil redistribution processes directly with 137Cs redistribution. Emphasis is placed on the spatial representation of soil redistribution processes and the adequate simulation of tillage processes. The benefits of the presented model arise from the two‐dimensional spatial integration of mass balance models with soil erosion models. No a priori assumptions about the intensity of any soil redistribution process are necessary and the level of agreement between observed and simulated 137Cs inventories enables us to evaluate the performance of the model. The spatial implementation and the use of fuzzy parameter sets also allow us to assess the uncertainties associated with soil erosion estimates. It was shown that an adequate simulation of tillage processes is necessary and that simplified tillage models may lead to erroneous estimates of soil redistribution. The model was successfully applied to a study site in the Belgian Loam Belt and the results indicated that tillage is the dominant process. Furthermore, the uncertainties associated with the estimation of water erosion rates were much higher than those associated with tillage, especially for depositional areas. Copyright © 2003 John Wiley & Sons, Ltd.
Anthropic aggradation of the Waiho River, Westland, New Zealand: microscale modelling
Authors: Davies Timothy R. H. , McSaveney Mauri J. , Clarkson Paul J. 
Published: February 2003

AbstractLong‐term aggradation of the Waiho River, South Westland, New Zealand, has now raised the head of its alluvial fan to unprecedented elevations. In its natural state the river would, like all other major rivers in the area, be somewhat incised into its fanhead. The only relevant factor able to account for the aggradation is the presence of control banks (‘stopbanks’ in local parlance) that restrict the ability of the river to move over the whole of its natural fanhead.A 1 : 3333 scale physical hydraulic model (a ‘microscale’ model) was used to study this situation. An alluvial fan was generated in the model and allowed to develop to equilibrium with steady inputs of water and sediment within boundaries geometrically similar to those of the natural unrestricted Waiho River. The boundaries were then altered to represent the presence of the stopbanks, and the fan allowed to continue evolving under the same water and sediment inputs. The model fanhead aggraded in a spatial pattern similar to that recorded on the Waiho.Taking into consideration the limitations of microscale modelling, these results indicate that the aggradation in the Waiho is a result of the lateral restriction of the river by stopbanks. This poses fundamental questions about the variables that control the behaviour of alluvial fans. The results also suggest that microscale modelling can be used to make reliable quantitative predictions of the effects of engineering works on rivers, in spite of the low level of dynamic similarity with the prototype compared to that in larger‐scale models. Copyright © 2003 John Wiley & Sons, Ltd.
Discussion on ‘The extent of soil erosion in Upland England and Wales’
Authors: Warburton J. , Evans M. G. , Johnson R. M. 
Published: February 2003

AbstractA recent survey by McHugh et al. (Earth Surface Processes and Landforms, 2002, Vol. 27, pp. 99–107), on the extent of soil erosion in upland England and Wales has several important limitations which should be considered when evaluating the significance of the results. The main limitations focus on an inadequate definition of the field survey methods; a lack of appreciation of the geomorphological context of the results; and no linking of erosion loss to timescale. An alternative approach based on sediment budget analysis provides reliable estimates of erosion and deposition; an indication of how upland sediment systems operate; and the relative significance of slope and channel processes. We believe it is more productive to have several strategically placed sediment budget assessments in the uplands of England and Wales than a rigid countrywide grid survey. Copyright © 2003 John Wiley & Sons, Ltd.
Response to discussion on ‘The extent of soil erosion in upland England and Wales’
Authors: McHugh M. , Harrod T. R. , Morgan R. P. C. 
Published: February 2003

AbstractThe research described in the paper by McHugh et al. (Earth Surface Processes and Landforms, 2002, Vol. 27, pp. 99–107) was based upon a fundamental, national baseline study initiated to assess, in an objective and statistically sound manner, the scale of upland soil erosion in England and Wales. It was proposed in direct response to the Royal Commission on Environmental Pollution's concern over loss of upland soils and on the basis that catchment‐based studies, which may be used to understand erosion in those catchments, are of limited value in understanding erosion within the uplands as a whole.To achieve its objectives, the research was conducted at a single scale and focused on assessment of individual erosion features within over four hundred upland field sites. The research suggestions raised by Warburton et al. (Earth Surface Processes and Landforms, 2003, Vol. 28, pp. 219–223), which included appreciation of the context of the plots within the larger sediment system and investigation of the fate of mobilized sediments, are valid but do not pertain to the research described by McHugh et al.Here we address the principal observation of Warburton et al. by clarifying methodological points on the assessment of the scale of erosion and deposition features. We also outline why the research was not an attempt to end discussion on the issue but was rather a first attempt to evaluate upland soil erosion in England and Wales, to contribute to an understanding of upland conditions and to provide a baseline study for further research. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of menadione (vitamin K3) addition on lipid oxidation and tocopherol content in plant oils
Authors: Kupczyk Bogumiła , Gogolewski Marek 
Published: February 2003

AbstractThe effect of added menadione (vitamin K3) to stored corn and wheat germ oil on the dissolution and dimerization of natural tocopherols and auto‐oxidation of triacylglycerols were investigated. Samples of corn and wheat germ oils pure and with added menadione were stored at +20°C in brown and transparent glass bottles. During storage their peroxide value, changes of the content of fatty acids and dissolution of tocopherols were measured. Destruction of individual tocopherols in tested oils with added menadione stored in both dark and transparent glass bottles was greater than in these oil samples without menadione. However, the degradation of individual tocopherols was different in each oil. Addition of menadione to the both oils resulted in accelerated the process of auto‐oxidation of these oils. The corn oil stored in transparent bottles was oxidized faster than the one stored in brown bottles. The pro‐oxidant activity of menadione was additionally activated by light. In contrast, in the cause of germ oil, the process of auto‐oxidation was very fast regardless of sort of container. Addition of menadione to the plant oils influenced the dissolution of natural tocopherols but did not influence the dimerization of tocopherols. As from the experiment, the addition of menadione to the oils decreased their nutritive value.
A parrtial supplementation of pasteurized milk with vitamin C, iron and zinc
Authors: Biringen Löker G. , Uǧur M. , Yıldız M. 
Published: February 2003

AbstractAfter supplementation trials, vitamin C, iron and zinc levels were increased by 1789%, 59% and 30%, respectively. Partially supplemented pasteurized milk could be a new alternative with its high nutritive value, good sensory properties and low cost.
Presence of two forms of methylated (–)‐epigallocatechin‐3‐gallate in green tea
Authors: Amarowicz Ryszard , Shahidi Fereidoon 
Published: February 2003

AbstractCrude catechins extract from Chinese green tea were fractionated using Sephadex LH‐20 column chromatography. The fraction containing (–)‐epigallocatechin‐3‐gallate (EGCG) was then subjected to a semipreparative high‐performance liquid chromatography (HPLC). Using a mobile phase of water : dimethyl formamide : methanol : acetic acid (157 : 49 : 2 : 1 v/v/v/v( the mixture of two methylated catechins was separated and isolated. According to mass spectrometry (MS) and nuclear magnetic resonance (1H‐NMR) date, these compounds were identified as (–)‐epigallocatechin‐3‐(3‐O‐methylgallate) and (–)‐epigallocatechin‐3‐(4‐O‐methylgallate).
Effect of temperature on sorption isotherms of Brussels sprout
Authors: Irzyniec Zbigniew , Klimczak Jolanta 
Published: February 2003

AbstractThe effect of temperature (0, 20 and 40°C) on sorptivity of freeze‐dried Brussels sprout was studied. It was checked which of the sorption isotherm equations that included temperature was the best to estimate experimental data. The surface area of a monolayer and isosteric heat of sorption was calculated. From the tested equations the Guggenheim‐Anderson‐de Boer (GAB) and Oswin equations appeared to be the best for describing sorption isotherms of freeze‐dried Brussels sprout. The Clausius‐Clapeyron equation was found suitable for the calculation of pure isosteric heat of sorption.
Biochemical and physical properties of some walnut genotypes (Juglans regia, L.)
Authors: Çaǧlarırmak Necla 
Published: February 2003

AbstractWalnut (Juglans regia L.) is a plant that has significant economical value and medicinal importance for human health. It is consumed in large quantities by people, therefore, it has a very important place in the public nutritive habits. Turkey has a very good walnut population of walnut varieties when compared to other parts of the world. Our objective was to investigate kernel properties and fatty acid composition, proximate composition and minerals of genotypes that are commonly grown in Turkey. Investigated genotypes were S¸ebin‐Type‐I, Körcegöz, Karabodur, Tozanı and Güvenli. Physical properties are attributed to quality criteria of nuts. S¸ebin Type‐I and Güvenli showed a good quality according to the test results. Average fatty acid compositions of genotypes (%) were 16 : 0; 6.88, 18 : 0; 7.50, 18 : 1; 21.16, 18.2; 43.41, 18 : 3; 6.25: 20 : 0; 11.75 for S¸ebin‐Type‐I, Körcegöz, Karabodur, Tozanlı and Güvenli, respectively. Proximate compounds (%) were: protein, 13.77; ash, 1.81; moisture, 2.98; fat, 62.84; total carbohydrate, 18.67. Average mineral contents (mg/100 g) were: P, 316.0; K, 270.0; Ca, 85.0; Mg, 90.0; Zn, 2.01; Mn, 2.46; Cu, 1.01; Fe, 2.90; B, 1.03.
Effects of ochratoxin A on micronucleus frequenncy in human lymphocytes
Authors: Dönmez‐Altuntaş Hamiyet , Hamurcu Zuhal , İmamoǧlu Nalan , Liman Bilal Cem 
Published: February 2003

AbstractOchratoxin A (OTA( a nephrotoxic and carcinogenic mycotoxin, was investigated to examine its potency to induce micronuclei (MN) in cultured human lymphocytes. Lymphocyte cultures were treated for the last 48 h with OTA at concentrations of 25 μM, 10 μM, 1 μM, 100 nM, 10 nM, 1 nM, and 100 pM and absolute ethanol. At the highest concentration, OTA was found to induce MN in cytokinesis‐blocked lymphocytes (p < 05). The 25 μM OTA concentration also led to a clear decrease in the percentage of binucleated cells, probably due to cytotoxicity. OTA at the other concentrations tested did not induce MN frequency. These results indicate that a high concentration of OTA is genotoxic in cultured human lymphocytes.
Antioxidant activity of Egyptian Eucalyptus camaldulensisvar. brevirostrisleaf extracts
Authors: El‐Ghorab Ahmed H. , El‐Massry Khaled F. , Marx Friedhelm , Fadel Hoda M. 
Published: February 2003

AbstractLeaves from Eucalyptus camaldulensis var. brevirostris trees, planted in the Nile delta in Egypt, were examined for the antioxidant activity of their nonvolatile compounds. The extracts obtained by ethanol digestion and by supercritical fluid extraction (SFE; CO2 with 15% ethanol) showed the most promising antioxidative activities. In order to identify the most active compounds, both extracts were subjected to a semipreparative reversed‐phase HPLC separation, the main fractions were collected, tested for antioxidative activity and analysed by different chromatographical and spectroscopical methods for identification of the most relevant compounds. Gallic and ellagic acid were found to be the prevailing antioxidants in the ethanolic extract. The main two compounds of the SFE extract with antioxidative activity revealed to be flavones. To a high degree of probability they were identified as 5‐hydroxy‐7,4′‐dimethoxy flavone and 5‐hydroxy‐7,4′‐dimethoxy‐8‐methyl flavone, respectively. The extracts obtained by ethanol digestion were dried and administered to rats for toxicity evaluation (up to 3 g/kg body weight). No mortality was observed which indicates a very low lethality of the tested extract.