bluuebunny/crossref_metadata_2025_split huggingface dataset:
Composition and stability of soil aggregates in Fluvisols under forest, meadows, and 100 years of conventional tillage
Authors: Gajić Boško , Đurović Nevenka , Dugalić Goran 
Published: April 2010

AbstractConversion of meadow and forest ecosystems to agricultural land generally leads to changes in soil structure. This comparative study presents the composition and stability of structural aggregates in humus horizons (0–30 cm) of noncarbonate silty‐clay Fluvisols in the Kolubara River Valley, W Serbia. Aggregates collected from under a native forest were compared to aggregates from meadows and arable fields which underwent crop rotation for > 100 y. The results show that size distribution and stability of structural aggregates in the humus horizons of arable soil are significantly impaired due to long‐term anthropogenization. In the humus horizons, the content of the agronomically most valuable aggregates (0.25–10 mm) decreased by a factor of ≈ 2, from 68%–74% to 37%–39%, while the percentage of cloddy aggregates (>10 mm) increased by a factor of ≈ 2, from 23%–31% to 48%–62%, compared to forest aggregates. The long‐term‐arable soil had significantly (p < 0.05) lower aggregate stability, determined by wet sieving, than meadow and forest soils. The lowest aggregate stability was found in aggregates > 3 mm. Their content is ≈ 2.5–3 times lower in arable soil (13%–16%) than in forest soil (32%–42%) at a depth of 0–20 cm. The largest mean weight diameters of dry aggregates (dMWD) with a range between 12.6 and 14.7 mm were found in arable soil, vs. 9.5–9.9 mm in meadow and 6.5–8.3 mm in forest. The arable soil had significantly lower mean weight diameters of wet‐stable aggregates (wMWD) and a lower structure coefficient (Ks) than forest and meadow soils. The dispersion ratio (DR) of arable soil was significantly higher than that of forest and meadow soils. Forest and meadow showed a significantly higher soil organic‐matter content (SOM) by 74% and 39%, respectively, compared with arable soil, while meadow uses decreased the SOM content by 57% compared with forest at a depth of 0–10 cm. In conclusion, the results showed that long‐term conventional tillage of soils from natural forest and meadow in the lowland ecosystems of W Serbia degraded soil aggregate–size distribution and stability and reduced SOM content, probably resulting in lower productivity and reduced crop yields.
Modeling carbon dynamics in subsoils using simple models
Authors: Helfrich Mirjam , Flessa Heiner , Ludwig Bernard 
Published: April 2010

AbstractSoil C dynamics below the plow layer have been little studied, despite a suspected large C‐stabilization potential of subsurface horizons. The objective of this study was to test two simple models (model A: single compartment for C3‐ and for C4‐derived C; model B: division of C3‐ and C4‐derived C into active and passive compartments) in their ability to simulate the C dynamics in subsoil horizons of a Haplic Phaeozem after conversion from C3 (rye) to C4 cropping (maize). The models were calibrated on an unfertilized maize soil and then validated on a maize soil with NPK fertilization. Both models simulated well C3‐C and C4‐C dynamics in the investigated soil depths (20–40 cm and 40–60 cm). In all cases, the model efficiency EF was > 0, which indicated that the simulated values described the trend in the measured data better than the mean of the observations. However, we observed some inconsistency in the obtained parameter set (e.g., a higher proportion of passive C for C4‐derived than for C3‐derived C or a very low decomposition rate constant for passive C4‐C in 40–60 cm), which we assume to result from data restrictions on the investigated soils. More detailed data on SOC pools and turnover rates in subsoils which are generally not yet available for most experimental plots is vitally needed—especially for applying more sophisticated C‐dynamics models.
Effects of a biomimetic iron‐porphyrin on soil respiration and maize root morphology as by a microcosm experiment
Authors: Gelsomino Antonio , Tortorella Demetrio , Cianci Vincenzo , Petrovičová Beatrix , Sorgonà Agostino , Piccolo Alessandro , Rosa Abenavoli Maria 
Published: April 2010

AbstractA synthetic, water‐soluble iron‐porphyrin [meso‐tetra(2,6‐dichloro‐3‐sulfonatophenyl) porphyrinate of Fe(III) chloride] has recently been proposed as a biomimetic catalyst in the process of oxidative polymerization of terrestrial humic acids, to increase their conformational stability and thus contribute to a reduction of soil CO2 release into the atmosphere. This study was aimed at investigating changes in selected soil chemical properties, CO2 efflux, and maize root morpho‐topology after the addition of iron‐porphyrin as a microcosm‐style experiment, located in a greenhouse. The addition of mature compost was also included as an experimental factor in order to reveal synergistic effects in regard to freshly added organic materials. Iron‐porphyrin determined a negligible effect on soil organic budget in both unplanted and planted microcosms. Conversely, the biomimetic catalyst was found to have significant and contrasting effects on soil respiration, apparently reflecting different iron porphyrin–plant–compost interactions. Consequently, iron‐porphyrin significantly reduced CO2 efflux from the bare (unplanted) soil, which was, conversely, stimulated in maize‐planted microcosms. Additionally, combined iron‐porphyrin and compost addition synergistically acted in increasing soil respiration in planted microcosms. Moreover, root biomass was increased with the addition of iron‐porphyrin, and a further effect on maize root morphology was noted when used in combination with compost; notably the length of coarse and fine roots increased. We hypothesized that the efficacy of iron‐porphyrin in reducing CO2 efflux from soil may be mediated by morphological changes in the plant‐root system.
Comparison of critical limits for crop plant growth based on different indicators for the state of soil compaction
Authors: Kaufmann Manfred , Tobias Silvia , Schulin Rainer 
Published: April 2010

AbstractSoil compaction affects physical soil condition, in particular aeration, soil strength, and water availability and has adverse effects on plant growth. Bulk density is the most frequently used indicator to describe the state of compaction of a soil. However, this parameter lacks a direct functional relationship with plant growth. Various indicators have been proposed to simultaneously characterize the state of compaction of agricultural soil and its suitability for plant growth. This paper examines and compares the critical limits for crop plant growth based on three of these indicators: packing density, least limiting water range, and S parameter (the latter is the slope of the soil water‐retention curve in the inflexion point). In a first step, we reviewed the literature for published optimum and limiting values of bulk density and found that these values were highly dependent on clay and silt content. Converting them into corresponding values of packing density (composite index of bulk density and clay content), a value of 1.70 was found to effectively distinguish between optimum and limiting soil conditions for plant growth. In a second step, the packing density of 59 soil horizons sampled in N Switzerland was compared with the least limiting water range and the S parameter of these soil horizons (both determined by means of pedotransfer functions taken from the literature). A linear relationship between the three parameters was found, which allowed for a comparison of the published critical limits for plant growth based on these parameters. The critical limits of the three indicators, which had been postulated independently of each other in the literature, were found to agree well with each other. This means that all of them could equally be used to describe the compaction state of a soil and its physical suitability for plant growth. However, the proposed critical limits of packing density, least limiting water range, and S parameter still need further validation by field studies relating plant growth to soil compaction.
Accumulation of cadmium, fluorine, magnesium, and zinc in soil after application of phosphate fertilizer for 31 years in a grazing trial
Authors: McGrath Dave , Tunney Hubert 
Published: April 2010

AbstractPhosphate fertilizers are recognized as a potential source of elements that could contribute to soil pollution. The objective of this study was to determine the extent to which use of phosphate fertilizer in the past had resulted in an increase in heavy‐metal content in Irish soils. Samples were taken from a long‐term replicated (six replicates of 0.18 ha each) plot experiment with grazing cattle. Phosphate as superphosphate had been applied at two rates, 0 and 930 kg ha–1 total P, over a 31 y period. Phosphorus, pH, soil organic matter, Cd, F, Mg, and Zn were measured in 0–10 and 10–20 cm soil layers in addition to extractable P and Mg (Morgan's solution) and Zn (0.5M EDTA). Increases in the phosphate‐enriched soil were significant at p < 0.05 except for F at both soil layers and for Cd at the 10–20 cm layer (p < 0.1) Recoveries for P, Cd, and F were in fair agreement with application. High recoveries of total Mg and Zn were encountered which could not readily be explained. These increases were paralleled by increases in extractable‐soil‐test values for these elements. Accumulation in soil of P over the period was such as to now necessitate little application of this element to soil for the near future. At the same time, increase in soil Cd was small, little more than 0.05 mg kg–1 in soil, although it amounted to a sizable proportion of Cd in the soil. Similarly, increases in other elements, although real, would not lead to major concerns at the present time.
Effect of air‐drying on phosphorus fractions in clay soil
Authors: Soinne Helena , Räty Mari , Hartikainen Helinä 
Published: April 2010

AbstractDespite the publication of a number of papers dealing with the effect of drying on the soil labile P pool, less attention has been paid to the possible drying‐evoked changes in the more stable P pools. We applied Hedley's sequential fractionation procedure that aims at quantifying soil P reserves according to their decreasing plant availability to examine the effects of drying on soil P fractions in clayey soil samples of different cultivation history. To further investigate the contribution of organic matter disruption to the solubility of soil P, the P extracted in each fractionation step was divided into two size classes by filtering the suspension through a 0.2 μm membrane filter. There were no air‐drying‐induced changes in the total amount of P extracted in each fractionation step. However, air‐drying changed the distribution of water‐extractable P in size fractions; increase in the small‐sized P took place at the expense of large‐sized P. Air‐drying increased also small‐sized molybdate‐unreactive P (MUP) in the NaOH fraction giving evidence that drying‐induced alterations take place also in less labile P forms. The results revealed that air‐drying alters the extractability and distribution of P in various pools rather than the total amount of extracted P and that a large proportion of H2O‐ and NaOH‐extractable large‐sized MUP may remain undetected if only filtered samples are analyzed.
Molecularly imprinted hydrogel displaying reduced non‐specific binding and improved protein recognition
Authors: Tov Ortal Yom , Luvitch Shlomit , Bianco‐Peled Havazelet 
Published: April 2010

AbstractA novel approach for enhancing protein recognition in molecularly imprinted hydrogel (MIH) is presented. This approach was developed based on the hypothesis that the number of specific binding sites created in the previously described MIH is very small, thus attempts to enhance the capacity result in most cases in additional non‐specific binding and loss of selectivity. Thus, blocking the non‐specific binding sites could lead to higher capacities and better selectivity. To test this hypothesis, MIH interpenetrating networks designed to block non‐specific binding sites were synthesized using two separate stages of polymerization. Re‐binding of the template protein (lysozyme) and a competitor protein (cytochrome C) was measured, and the results were compared with the similar experiment performed using a control non‐imprinted hydrogel and a “conventional” MIH. The imprinting efficacy of the MIH interpenetrating network was found to be much higher than that of the controls. Furthermore, competitive adsorption assays have demonstrated the superiority of the new formulation.
Attributes affecting the level of tourist satisfaction with and loyalty towards theatrical performance in China: Evidence from a qualitative study
Authors: Song Hanqun , Cheung Catherine 
Published: April 2010

AbstractThis study seeks to explore attributes affecting the level of tourist satisfaction with and loyalty towards theatrical performance in China. Based on four focus group discussions with 31 participants, the study identifies 34 attributes that affect the level of tourist satisfaction with theatrical performance, and groups them into five categories: stage, performance, venue, service and tourist‐related attributes. The findings on tourist loyalty reveal that 21 of the 31 respondents would not watch the same theatrical performance alone in the future; however, they would recommend it to others. The study concludes with a discussion of the rich and insightful findings and their implications for tourism industry practitioners. Copyright © 2010 John Wiley & Sons, Ltd.
The (193–209) 17‐residues peptide of bovine β‐casein is transported through Caco‐2 monolayer
Authors: Regazzo Daniela , Mollé Daniel , Gabai Gianfranco , Tomé Daniel , Dupont Didier , Leonil Joëlle , Boutrou Rachel 
Published: April 2010

AbstractAlthough the bioavailability of large peptides with biological activity is of great interest, the intestinal transport has been described for peptides up to only nine residues. β‐casein (β‐CN, 193–209) is a long and hydrophobic peptide composed of 17 amino acid residues (molecular mass 1881 Da) with immunomodulatory activity. The present work examined the transport of the β‐CN (193–209) peptide across Caco‐2 cell monolayer. In addition, we evaluated the possible routes of the β‐CN (193–209) peptide transport, using selective inhibitors of the different routes for peptide transfer through the intestinal barrier. The results showed that the β‐CN (193–209) peptide resisted the action of brush‐border membrane peptidases, and that it was transported through the Caco‐2 cell monolayer. The main route involved in transepithelial transport of the β‐CN (193–209) peptide was transcytosis via internalized vesicles, although the paracellular transport via tight‐junctions could not be excluded. Our results demonstrated the transport of an intact long‐chain bioactive peptide in an in vitro model of intestinal epithelium, as an important step to prove the evidence for bioavailability of this peptide.
Changes in arterial blood pressure after single oral administration of milk‐casein‐derived peptides in spontaneously hypertensive rats
Authors: Miguel Marta , Gómez‐Ruiz José Ángel , Recio Isidra , Aleixandre Amaya 
Published: April 2010

AbstractIn this study we evaluated the short‐term oral antihypertensive effect of several peptide sequences isolated from casein fractions, previously characterized as in vitro angiotensin‐converting enzyme‐inhibitors, in spontaneously hypertensive rats (SHR). Systolic blood pressure (SBP) and the diastolic blood pressure (DBP) of the rats were measured by the tail cuff method before administration and also 2, 4, 6, 8 and 24 h post‐administration. The sequences LVYPFTGPIPN, HLPLP, IAK, YAKPVA and WQVLPNAVPAK showed a clear decrease in SBP and DBP in SHR. HPHPHLSF caused a significant decrease of the DBP in the SHR, but this sequence did not modify the SBP of these animals in a significant manner. KKYNVPQL did not modify SBP in the SHR, and caused a slight, but significant and maintained, decrease in DBP in these animals. SBP and DBP returned to baseline values 24 h post‐administration of all peptides. In conclusion, these peptides are bioactive ingredients with potential benefit in the prevention and treatment of hypertension or other associated disorders.
Inhibitory effects of 5‐hydroxy polymethoxyflavones on colon cancer cells
Authors: Qiu Peiju , Dong Ping , Guan Huashi , Li Shiming , Ho Chi‐Tang , Pan Min‐Hsiung , McClements David Julian , Xiao Hang 
Published: April 2010

AbstractHydroxylated polymethoxyflavones (PMFs) are a class of novel flavonoid compounds mainly found in citrus plants. We studied the effects of three major 5‐hydroxy PMFs, namely: 5‐hydroxy‐6,7,8,3′,4′‐pentamethoxyflavone, 5‐hydroxy‐3,6,7,8,3′,4′‐hexamethoxyflavone, and 5‐hydroxy‐6,7,8,4′‐tetramethoxyflavone, on human colon cancer HCT116 and HT29 cells. Their effects were compared with those produced by their permethoxylated counterparts, namely: nobiletin, 3,5,6,7,8,3′,4′‐heptamethoxylflavone, and tangeretin. 5‐Hydroxy PMFs showed much stronger inhibitory effects on the growth of the colon cancer cells in comparison with their permethoxylated counterparts, suggesting the pivotal role of hydroxyl group at 5‐position in the enhanced inhibitory activity by 5‐hydroxy PMFs. Flow cytometry analysis demonstrated that three 5‐hydroxy PMFs produced different effects on the cell cycle and apoptosis, which may suggest that three 5‐hydroxy PMFs act through different mechanisms. For example, 5‐hydroxy‐6,7,8,3′,4′‐pentamethoxyflavone caused cell cycle arrest at G2/M phase in HT29 cells, while 5‐hydroxy‐3,6,7,8,3′,4′‐hexamethoxyflavone led to significant G0/G1 phase arrest. In contrast, 5‐hydroxy‐6,7,8,4′‐tetramethoxyflavone increased sub‐G0/G1 cell population, which has been confirmed to be due to enhanced apoptosis. Our results further demonstrated that the inhibitory effects of 5‐hydroxy PMFs were associated with their ability in modulating key signaling proteins related to cell proliferation and apoptosis, such as p21Cip1/Waf1, CDK‐2, CDK‐4, phosphor‐Rb, Mcl‐1, caspases 3 and 8, and poly ADP ribose polymerase (PARP).
Buffer layers and transparent conducting oxides for chalcopyrite Cu(In,Ga)(S,Se)2based thin film photovoltaics: present status and current developments
Authors: Naghavi N. , Abou‐Ras D. , Allsop N. , Barreau N. , Bücheler S. , Ennaoui A. , Fischer C.‐H. , Guillen C. , Hariskos D. , Herrero J. , Klenk R. , Kushiya K. , Lincot D. , Menner R. , Nakada T. , Platzer‐Björkman C. , Spiering S. , Tiwari A.N. , Törndahl T. 
Published: April 2010

AbstractThe aim of the present contribution is to give a review on the recent work concerning Cd‐free buffer and window layers in chalcopyrite solar cells using various deposition techniques as well as on their adaptation to chalcopyrite‐type absorbers such as Cu(In,Ga)Se2, CuInS2, or Cu(In,Ga)(S,Se)2. The corresponding solar‐cell performances, the expected technological problems, and current attempts for their commercialization will be discussed. The most important deposition techniques developed in this paper are chemical bath deposition, atomic layer deposition, ILGAR deposition, evaporation, and spray deposition. These deposition methods were employed essentially for buffers based on the following three materials: In2S3, ZnS, Zn1 − xMgxO. Copyright © 2010 John Wiley & Sons, Ltd.
Microcrystalline silicon solar cells: effect of substrate temperature on cracks and their role in post‐oxidation
Authors: Python M. , Dominé D. , Söderström T. , Meillaud F. , Ballif C. 
Published: April 2010

AbstractMicrocrystalline silicon (µc‐Si:H) cells can reach efficiencies up to typically 10% and are usually incorporated in tandem micromorph devices. When cells are grown on rough substrates, “cracks” can appear in the µc‐Si:H layers. Previous works have demonstrated that these cracks have mainly detrimental effects on the fill factor and open‐circuit voltage, and act as bad diodes with a high reverse saturation current. In this paper, we clarify the nature of the cracks, their role in post‐oxidation processes, and indicate how their density can be reduced. Regular secondary ion mass spectrometry (SIMS) and local nano‐SIMS measurements show that these cracks are prone to local post‐oxidation and lead to apparent high oxygen content in the layer. Usually the number of cracks can be decreased with an appropriate modification of the substrate surface morphology, but then, the required light scattering effect is reduced due to a lower roughness. This study presents an alternative/complementary way to decrease the crack density by increasing the substrate temperature during deposition. These results, also obtained when performing numerical simulation of the growth process, are attributed to the enhanced surface diffusion of the adatoms at higher deposition temperature. We evaluate the cracks density by introducing a fast method to count cracks with good statistics over approximately 4000 µm of sample cross‐section. This method is proven to be useful to quickly visualize the impact of substrate morphology on the density of cracks in microcrystalline and in micromorph devices, which is an important issue in the manufacturing process of modules. Copyright © 2010 John Wiley & Sons, Ltd.
Four‐junction solar cells using lattice‐matched II–VI and III–V semiconductors
Authors: Wu S.‐N. , Ding D. , Johnson S. R. , Yu S.‐Q. , Zhang Y.‐H. 
Published: April 2010

AbstractFour‐junction solar cells are designed using lattice‐matched II–VI (ZnCdSeTe) and III–V (AlGaAsSb) semiconductors grown on GaSb substrates. These materials have a zinc blende crystal structure, similar thermal expansion coefficients, and bandgaps that cover the entire solar spectrum. Numerical simulations of the energy conversion efficiencies of various designs for both the AM0 and AM1.5D spectra are performed using published material parameters. These results indicate that the achievable 1 sun AM0 efficiency is 43% for an optimal design and 40% for a more practical design; for comparison the ideal limit provided by Henry's model is 49%. While for the AM1.5D spectrum an optimal design can reach 46% under 1 sun and 55% under 1000 suns while a more practical design can reach 44 and 54%, respectively; for comparison Henry's model gives 51 and 62%, respectively. Copyright © 2010 John Wiley & Sons, Ltd.
Influence of precursor layer ablation on laser doping of silicon
Authors: Köhler J. R. , Eisele S. 
Published: April 2010

AbstractThis paper presents a numerical model, which quantitatively demonstrates that ablation and partial recondensation of the dopant precursor layer are some of the dominating physical processes in laser doping (LD) of crystalline silicon. Our pulsed LD process uses a line focused laser beam, enabling the creation of solar cell emitters without the generation of dislocations, if the width w of the short axis of the line focus is w < 10 μm. The concentration profiles of the dopant atoms strongly depend on the pulse energy density Ep, the pulse to pulse separation Δx and the number of laser scans Ns. By comparing measured with modeled concentration profiles, we are able to evaluate the ablation width as well as the amount of the ablated precursor layer. In case of a sputtered phosphorus precursor layer, the ablation width wa is wa = 6 μm, whereas the width of the molten silicon layer wm is wm = 5 μm. The model also explains the dependence of experimental dopant concentration profiles on the number of subsequent laser scans Ns and pulse to pulse separation Δx. Copyright © 2010 John Wiley & Sons, Ltd.