bluuebunny/crossref_metadata_2025 huggingface dataset:
Geochronology of the Turkana Depression of Northern Kenya and Southern Ethiopia
Authors: Brown Francis H. , Mcdougall Ian
Published: December 2011

Mesozoic and Cenozoic sedimentary rocks in the Turkana Depression of northern Kenya and southern Ethiopia rest on basement rocks that yield K/Ar cooling ages between 433 and 522 Ma. Proven Cretaceous strata are exposed in Lokitaung Gorge in northwest Kenya. Eocene basalts and rhyolites in Lokitaung Gorge, the Nabwal Hills, and at Kangamajoj, date between 34 and 36 Ma, recording the earliest volcanism in the region. Oligocene volcanic rocks, with associated fossiliferous sedimentary strata at Eragaleit, Nakwai, and Lokone, all west of Lake Turkana, are 23 to 28 Ma old, as is the Langaria Formation east of Lake Turkana. Lower and Middle Miocene volcanic and sedimentary sequences are present both east and west of Lake Turkana, where ages from 17.9 to 9.1 Ma have been measured at many levels. Upper Miocene strata are presently known only at Lothagam, with ages ranging from 7.4 to 6.5 Ma. Deposition of Pliocene strata of the Omo Group begins in the Omo‐Turkana, Kerio, and South Turkana basins ∼4.3 Ma ago and continues in parts of those basins until nearly the present time, but with some gaps. These strata are linked through volcanic ash correlations at many levels, as are Pleistocene strata of the Omo Group (principally the Shungura, Koobi Fora, and Nachukui formations). 40Ar/39Ar dates on many volcanic ash layers within the Omo Group, supplemented by K/Ar ages on intercalated basalts and paleomagnetic polarity stratigraphy, provide excellent age control from 4.2 to 0.75 Ma, although there is a gap in the record between ∼1 Ma and 0.8 Ma. Members I to III of the Kibish Formation in the lower Omo Valley record deposition between 0.2 and 0.1 Ma ago; Member IV, correlative with the Galana Boi Formation, was deposited principally between 12 and 7 ka BP. © 2011 Wiley Periodicals, Inc.
Stable Isotope Ecology in the Omo‐Turkana Basin
Authors: Cerling Thure E. , Levin Naomi E. , Passey Benjamin H.
Published: December 2011

Stable isotopes provide an independent assessment of paleoenvironments in the Omo‐Turkana Basin. Stable isotopes track the flow of oxygen and carbon through ecosystems and accordingly are not directly related to changes in mammalian faunal composition or sedimentology. Therefore, isotope studies give insight into the paleoenvironmental conditions in which human evolutionary trends have been recorded. The development of stable isotopes as indicators of continental environmental conditions has proceeded in parallel with questions about the conditions of human environment. What was the vegetation? How hot was it? How dry? What were the diets of animals living among early humans? And most persistently, how important were “savannas” to early hominids? In this review, we take the opportunity to provide extensive background on the use of isotopes in anthropological sites. The application of stable isotope ecology to anthropological sites in the Turkana Basin has a long history, but in many ways the Omo‐Turkana Basin has been a proving ground for the development of new proxy methods for understanding tropical terrestrial environments in the Neogene and Quaternary. For that reason, we also describe some of the fundamental aspects of isotope ecology that developed outside the field of paleoanthropology. © Wiley Periodicals, Inc.
Increased gene copy number of KIT and VEGFR2 at 4q12 in primary breast cancer is related to an aggressive phenotype and impaired prognosis
Authors: Johansson Ida , Aaltonen Kristina E. , Ebbesson Anna , Grabau Dorthe , Wigerup Caroline , Hedenfalk Ingrid , Rydén Lisa
Published: December 2011

Triple‐negative breast cancer (TNBC) is associated with poor prognosis and no targeted treatments are available for TNBC. Drugs inhibiting tyrosine kinases, such as vascular endothelial growth factor receptor 2 (VEGFR2) and KIT, have shown some promising results for patients with TNBC. The aim of the study was to investigate whether gains and/or amplifications of VEGFR2 and KIT, located at 4q12, occur in TNBC. Fluorescence in situ hybridization (FISH) was used to quantify gene copy numbers of VEGFR2 and KIT in 83 primary human breast cancers including 31 TNBCs. Gains were defined as ≥4 gene copies in >40% of the cancer cells, whereas amplification was defined as CEP >2 in more than 10% of the cancer cells. A tumor was considered FISH positive for KIT and/or VEGFR2 if it displayed copy number gain and/or amplification. Ten (32%) of the TNBCs were VEGFR2 FISH positive and nine (29%) were KIT FISH positive, whereas non‐TNBCs were FISH positive for VEGFR2 and KIT in nine (18%) cases for both genes, but no significant difference between TNBCs and non‐TNBCs was found. FISH positivity for VEGFR2 and KIT was significantly correlated (χ2 test, P < 0.001), and significantly related to ER negativity and high Nottingham histological grade (NHG). A significantly worse 5‐year breast cancer specific survival (BCSS) was seen for FISH positive cases. Increased copy number of VEGFR2 and KIT thus has the potential of functioning as a novel predictive biomarker for selected targeted therapy particularly in the difficult‐to‐treat TNBC patient category. © 2011 Wiley Periodicals, Inc.
Methods to separate observed global evapotranspiration into the interception, transpiration and soil surface evaporation components
Authors: Blyth Eleanor , Harding Richard John
Published: December 2011

Evaporation is made up of three components: interception, soil surface evaporation and transpiration. They each have different stores of water and different characteristic timescales. It would be useful to be able to identify the relative proportions of these components at large, even global, scales for land surface model validation. The possibility of separating out the components of observed evaporation at large scales is reviewed with reference to methods used at local scales, landscape scales and scales used in remote sensing. Many of the traditional methods used require intensive measurement programmes and are unlikely to be practical at large scales. New techniques using time‐series analysis may be used to deliver a global three‐component evaporation product. Copyright © 2011 John Wiley & Sons, Ltd.
Differential expression of iron metabolism proteins in diabetic and diabetic iron‐supplemented rat liver
Authors: Silva Maísa , de Brito Magalhães Cintia Lopes , de Paula Oliveira Riva , Silva Marcelo Eustáquio , Pedrosa Maria Lucia
Published: December 2011

Diabetes mellitus is associated with altered iron homeostasis that can potentially effect reactive oxygen species generation and contribute to diabetes‐related complications. We investigated, by quantitative polymerase chain reaction, whether the expression of liver hepcidin, ferritin, and TfR‐1 is altered in diabetes. Rats in the control (C) group received a standard diet; control iron (CI) group received a standard diet supplemented with iron; diabetic (D) group received an injection of streptozotocin; and diabetic iron (DI) group received streptozotocin and the diet with iron. Animals of the D group showed higher levels of serum iron, increased concentration of carbonyl protein, and a decrease in antioxidant status. Group D rats showed increased hepatic expression of Trf‐1 compared to the other groups. Iron supplementation reversed this increase. Hepcidin mRNA was 81% higher in DI than in C and CI rats. The results suggest that diabetes, with or without excess iron, can cause perturbations in iron status, hepcidin and Trf‐1 expression. © 2012 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26:123–129, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.20418
Interaction and protection mechanism between li@C60 and nucleic acid bases (NABs): Performance of PM6‐DH2 on noncovalent interaction of NABs‐Li@C60
Authors: Sun Wenming , Bu Yuxiang , Wang Yixuan
Published: December 2011

To discuss the protection mechanism of DNA from radiation as well as assess the performance of PM6‐DH2 on noncovalent interactions, the interaction of four nucleic acid bases (NABs) such as adenine (A), cytosine (C), guanine (G), and thymine (T), with Li@C60 was extensively investigated with the‐state‐of‐art theoretical methods describing noncovalent systems, like M06‐2x, PBE‐D, and PM6‐DH2 methods. In the gas phase, the binding strength of NABs to Li@C60 from M06‐2x decreases in the sequence, G>C>A>T. As dispersion was explicitly included, PBE‐D relatively enhances the binding of A and T and corrects the sequence to, G>A>C∼T. PM6‐DH2 predicted similar binding energies to those from PBE‐D within 0.5 kcal/mol and the same binding sequence, suggesting that the PM6‐DH2 method is promising for nano‐scale systems. In the aqueous solution, binding of NABs‐Li@C60 is considerably decreased, and the M06‐2X and PM6‐D methods yield a different sequence from the gas phase, G>A>T>C. The encapsulation of Li atom results in a lower IP for Li@C60 than those of NABs, and the dominant localization of single‐occupied molecular orbital on Li@C60 moiety of the complexes NABs‐Li@C60 further indicates that an electron would be ejected from Li@C60 upon radiation and Li@C60 is therefore able to protect DNA bases from radiation. In addition, it was revealed that Li prefers coordination with the hexagonal ring at Li@C60, which clarifies the existing controversy in this respect. Finally, Yang's reduced density gradient approach clearly shows that the weak and strong noncovalent interaction regions in the complexes, NABs‐Li@C60 and (NABs‐Li@C60)+. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Artichoke polyphenols induce apoptosis and decrease the invasive potential of the human breast cancer cell line MDA‐MB231
Authors: Mileo Anna Maria , Di Venere Donato , Linsalata Vito , Fraioli Rocco , Miccadei Stefania
Published: December 2011

The human breast cancer cell line, estrogen receptor negative, MDA‐MB231, was used to evaluate the antitumor effect of polyphenolic extracts from the edible part of artichokes (AEs). Treatment of cancer cells reduced cell viability and inhibited cell growth in a dose‐dependent manner. Importantly, AEs did not have any effect on normal breast epithelial cell line, MCF10A. Chlorogenic acid (ChA), the most representative component of the polyphenolic fraction of artichoke, had no prominent effects on the cell death rate of MDA‐MB231 cells. The addition of AEs to the cells, rather than ChA, triggered apoptosis via a mitochondrial and a death‐receptor pathway, as shown by the activation of caspase‐9 and caspase‐8, respectively. Furthermore, an increase of the Bax:Bcl2 ratio and up‐regulation of cyclin‐dependent kinase inhibitor, p21WAF1, crucial apoptotic players, were documented. According to our data on activation of caspase‐9, a loss of mitochondrial transmembrane potential (Ψm) was shown. Cell motility and invasion capabilities were remarkably inhibited by AEs‐treatment in highly invasive MDA‐MB231 cells. In addition, a significant decrease of proteolytic activity of metalloproteinase‐2 protein (MMP‐2), involved in degrading components of the extracellular matrix, was detected. Our findings indicate that AEs reduced cell viability, inhibited cell growth, triggered apoptotic mechanisms, and showed inhibitory properties against the invasive behavior of MDA‐MB231 cancer cell line. Altogether, these data indicate the potential chemopreventive activity of artichoke polyphenolic extracts. J. Cell. Physiol. 227: 3301–3309, 2012. © 2011 Wiley Periodicals, Inc.
MAD2 depletion triggers premature cellular senescence in human primary fibroblasts by activating a P53 pathway preventing aneuploid cells propagation
Authors: Lentini Laura , Barra Viviana , Schillaci Tiziana , Di Leonardo Aldo
Published: December 2011

The spindle assembly checkpoint (SAC) is a cellular surveillance mechanism that ensures faithful chromosome segregation during mitosis and its failure can result in aneuploidy. Previously, it was suggested that reduction of the MAD2 gene, encoding a major component of the SAC, induced aneuploidy in human tumor cells. However, tumor cell lines contain multiple mutations that might affect or exacerbate the cellular response to Mad2 depletion. Thus, the scenario resulting by Mad2 depletion in primary human cells could be different and more complex that the one depicted so far. We used primary human fibroblasts (IMR90) and epithelial breast cells (MCF10A) to gain further insight on the effects of genomic instability caused by transient Mad2 depletion. To this aim we depleted Mad2 by RNAi to a level shown by Mad2 haplo‐insufficient cells and found that induced aneuploidy caused premature cellular senescence in IMR90 cells. IMR90 cells showed typical features of senescent cells, like senescence‐associated (SA) ${\rm {\tilde {\beta }}}$ galactosidase expression, including up‐regulation of p53 and p14ARF proteins and of p21waf1 as well, but not of p16(INK4A) cyclin‐dependent kinase (Cdk) inhibitor. In contrast, after MAD2 post‐transcriptional silencing MCF10A cells in which the INK4A/ARF locus is deleted, showed both aneuploidy and a small increase of p53 and p21waf1 proteins, but not premature cellular senescence. Finally, our results provides an explanation of how a p53 controlled pathway, involving initially p21waf1 and then p14ARF, could minimize the occurrence of genomic alterations derived from chromosome instability induced by low amounts of MAD2 protein. J. Cell. Physiol. 227: 3324–3332, 2012. © 2011 Wiley Periodicals, Inc.
Estimation of thermal dose from MR thermometry during application of nonablative pulsed high intensity focused ultrasound
Authors: O'Neill Brian E. , Karmonik Christof , Sassaroli Elisabetta , Li King C.
Published: December 2011

Purpose:

To evaluate whether MR thermometry is sufficiently fast, accurate, and spatially resolved for monitoring the thermal safety of nonablative pulsed high intensity ultrasound (pHIFU) treatments.

Materials and Methods:

A combination of real MR thermometry data and modeling was used to analyze the effects of temporal and spatial averaging as well as noise on the peak temperatures and thermal doses that would be measured by MR thermometry.

Results:

MR thermometry systematically underestimates the temperature and thermal doses during pHIFU treatment. Small underestimates of peak temperature can lead to large underestimates of thermal dose. Spatial averaging errors are small for ratios of pixel dimension to heating zone radius less than 0.25, which may be achieved by reducing the voxel size or steering the acoustic beam. Thermal dose might also be underestimated for very short, high power pulses due to temporal averaging. A simple correction factor based on the applied power and duty cycle may be applied to determine the upper bound of this effect.

Conclusion:

The temperature and thermal dose measured using MR thermometry during pulsed HIFU treatment is probably sufficient in most instances. Simple corrections may be used to calculate an upper bound where this is a critical factor. J. Magn. Reson. Imaging 2012;35:1169‐1178. © 2011 Wiley Periodicals, Inc.
Toward MR‐guided high intensity focused ultrasound for presurgical localization: Focused ultrasound lesions in cadaveric breast tissue
Authors: Bitton Rachel R. , Kaye Elena , Dirbas Frederick M. , Daniel Bruce L. , Pauly Kim Butts
Published: December 2011

Purpose:

To investigate magnetic resonance image‐guided high intensity focused ultrasound (MR‐HIFU) as a surgical guide for nonpalpable breast tumors by assessing the palpability of MR‐HIFU‐created lesions in ex vivo cadaveric breast tissue.

Materials and Methods:

MR‐HIFU ablations spaced 5 mm apart were made in 18 locations using the ExAblate2000 system. Ablations formed a square perimeter in mixed adipose and fibroglandular tissue. Ablation was monitored using T1‐weighted fast spin echo images. MR‐acoustic radiation force impulse (MR‐ARFI) was used to remotely palpate each ablation location, measuring tissue displacement before and after thermal sonications. Displacement profiles centered at each ablation spot were plotted for comparison. The cadaveric breast was manually palpated to assess stiffness of ablated lesions and dissected for gross examination. This study was repeated on three cadaveric breasts.

Results:

MR‐ARFI showed a collective postablation reduction in peak displacement of 54.8% ([4.41 ± 1.48] μm pre, [1.99 ± 0.82] μm post), and shear wave velocity increase of 65.5% ([10.69 ± 1.60] mm pre, [16.33 ± 3.10] mm post), suggesting tissue became stiffer after the ablation. Manual palpation and dissection of the breast showed increased palpability, a darkening of ablation perimeter, and individual ablations were visible in mixed adipose/fibroglandular tissue.

Conclusion:

The results of this preliminary study show MR‐HIFU has the ability to create palpable lesions in ex vivo cadaveric breast tissue, and may potentially be used to preoperatively localize nonpalpable breast tumors. J. Magn. Reson. Imaging 2012;35:1089‐1097. © 2011 Wiley Periodicals, Inc.
Demographics, socio‐behavioral factors, and drug use patterns: What matters in spontaneous HCV clearance?
Authors: Shah Dimpy P. , Grimes Carolyn Z. , Brown Eric , Hwang Lu‐Yu
Published: December 2011

Hepatitis C virus (HCV), an emerging bloodborne pathogen, causes chronic liver disease frequently except in about 10–20% of infections which undergo spontaneous resolution. Investigating factors that influence viral clearance is essential to understand the natural history of this infection and establishing novel strategies for prevention and treatment. HCV clearance was estimated in a unique cohort of 1,260 HIV and HBV negative current drug users enrolled for a hepatitis B vaccination study. It was defined as the inability to detect viral RNA using a PCR method in presence of serum anti‐HCV antibody EIA. Associated demographic and socio‐behavioral factors including drug use patterns were identified from the enrolled subjects using multivariate regression analysis. 33.3% (420/1260) of drug users were found positive for anti‐HCV antibodies and 14.8% (62/420) of these individuals achieved viral clearance (negative PCR test). Race or ethnicity of the participants was the only significant factor associated with HCV clearance. Hispanics (OR = 3.4, 95% CI: 1.3–8.5, P = 0.01) and Caucasians (OR = 3.1, 95% CI: 1.5–6.6, P = 0.003) had significantly higher odds of clearing the virus compared to African Americans when adjusted for age and gender. None of the socio‐behavioral factors including alcohol intake and drug use patterns were significant determinants of HCV clearance. Racial or ethnic differences in HCV clearance were observed in this study suggesting an important role of host genetic susceptibility factors in determining the clinical course of this disease. Further research is needed to examine these genetic associations of host–virus relationships. J. Med. Virol. 84:235–241, 2012. © 2011 Wiley Periodicals, Inc.
Enteric viral pathogens in children with inflammatory bowel disease
Authors: Kolho Kaija‐Leena , Klemola Päivi , Simonen‐Tikka Marja‐Leena , Ollonen Marja‐Liisa , Roivainen Merja
Published: December 2011

The causes of exacerbations of inflammatory bowel disease (IBD) are unknown. The presence of RNA of an enterovirus, norovirus GI, norovirus GII, rotavirus, astrovirus, and sapovirus was sought in stool samples of 50 children (median age 12.9 years) undergoing gastrointestinal endoscopies for IBD or its exclusion (Crohn's disease n = 18, ulcerative colitis n = 13, indeterminate colitis n = 2, non‐IBD n = 17). Viral RNA was found in three fecal samples (norovirus GII n = 2, sapovirus n = 1), all in children without IBD. Therefore, enteral viruses may play only a minor role in IBD. J. Med. Virol. 84:345–347, 2012. © 2011 Wiley Periodicals, Inc.
Anisotrope Variation der gesättigten Wasserleitfähigkeit einer unterschiedlich beweideten Salzmarsch im Deichvorland
Authors: Zhang Haiquan
Published: December 2011

An horizontal und vertikal entnommenen Stechzylinderproben wurden gesättigte Wasserleitfähigkeit Kf. Lagerungsdichte und Porengrößenverteilung einer unterschiedlich beweideten Salzmarsch im Deichvorland auf die isotrope Verteilung der Werte im Raum hin untersucht. Die Ergebnisse zeigen, daß die gesättigte Wasserleitfähigkeit signifikant anisotrope Variation aufweist. Das Kv/Kh Verhältnis beträgt 0.38 bei Betrachtung der gesamten Profile und 0.44 für Oberboden. Diese Anisotropie ist wesentlich auf die geogene Wechselschichtstruktur der Sedimente zurückzuführen und wird immer geringer mit Fortschreiten der Bodenstrukturierung durch pedologische Prozesse. Die Beweidung hat signifikante Auswirkung auf die Kf−Werte ab einer Intensität von 1.0 SE/ha. Diese Auswirkung ist im deichnahen Bereich stärker ausgeprägt als im deichfernen. Die Kv‐ und Kh‐Werte werden jedoch gleichermaßen von der Beweidung beeinflußt, so daß die anisotrope Variation der Kf von der Beweidung unabhängig ist. Lagerungsdichte und Makroporosität (> 10 μm) der oberen Tiefen werden ebenfalls von der Beweidung signifikant beeinflußt, aber nicht von der Richtung der Probenahme. Kf korreliert signifikant mit dem Anteil an > 50 μm bzw. > 10 μm Poren. Die Korrelation zwischen Kf und der gesamten Porosität ist nicht signifikant. Die Anisotropie der Kf bedeutet eine Begünstigung des lateralen Wasserflusses in der Salzmarschhydrologie und sollte daher in der Ökosystemforschung und Modellierung des Wasser‐ und Stoffhaushaltes der Salzmarschen berücksichtigt werden.
Einige theoretische Überlegungen zur Spannungs‐ und Deformationsmessung in Böden und ihre meßtechnische Realisierung
Authors: Horn Rainer , Gräsle Werner , Kühner Stefan
Published: December 2011

In der vorliegenden Arbeit werden theoretische Überlegungen und Meßergebnisse zur räumlichen Druckforlpflanzung und Bodendeformation vorgestellt. Es kann gezeigt werden, daß unter idealisierten Bodenrinnenbedingungen eine Bodenbelastung stets zu einer Bodenverdichtung und Scherung als Teilkomponenten der Bodendeformation führt. Eine Quantifizierung der volumetrischen Verformung und der volumenkonstanten Deformation des homogenisierten Bodensubstrates macht deutlich, daß bis zu 60% als vertikale Deformation und bis zu 40% als volumenkonstante Verformung definiert werden muß. Die Folgen für die Eigenschaften der Bodenstruktur werden kurz diskutiert.
Kontamination von Trümmerschuttböden mit PAK
Authors: Smettan Ursula , Mekiffer Beate
Published: December 2011

Untersuchungen von Trümmerschuttböden zeigen, daß diese sehr stark mit PAK kontaminiert sind. Exemplarisch werden drei Bodenprofile eines Trümmergrundstückes detailliert beschrieben. Diese sind charakterisiert durch hohe Skelettgehalte aus Putz, Schlacke, Ziegel, Schiefer und Asche. Die sehr hohen PAK‐Gehalte stehen in Zusammenhang mit den Komponenten Schlacke und Kohle, wobei in den Horizonten, die von Schlacke/Ziegel‐Komponenten dominiert werden, ebenfalls hohe PAK‐Gehalte im Skelett vorhanden sind. Der Anteil der PAK mit der stärksten Wasserlöslichkeit an den 16 Einzel‐PAK ist gering. Der Hauptanteil der PAK wird durch die Gruppe Fluoranthen/Pyren/Benz(a)anthracen bestimmt. Eine tiefenabhängige Veränderung der Anteile der einzelnen PAK in Abhängigkeit von den unterschiedlichen Hauptkomponenten ist nicht erkennbar. Eluatuntersuchungen belegen, daß die Löslichkeit der PAK sehr gering ist und < 1% beträgt. Dabei gehen vor allem die niedrig kondensierten PAK wie z.B. Acenaphthylen und Acenaphthen in Lösung.

Detaillierte Bodenaufnahmen mit genauer Beschreibung der Komponenten ermöglichen daher eine Gefährdungsabschätzung für Nutzungsansprüche bereits ohne Laboranalyse sowie eine Kostenabschätzung für Entsorgung und Sanierung im Vorfeld von Baumaßnahmen. Da unterschiedliche Komponenten in Schuttböden unterschiedliche Kontaminationen bewirken, ist eine Trennung der Trümmerschuttböden, die reich an Brandasche und Schlacke sind, von den Bauschuttböden in der Klassifizierung erforderlich.
Nitratabbau in tieferen Bodenschichten süddeutscher Ackerstandorte auf Löß
Authors: Funk Reinhold , Maidl Franz‐Xaver , Fischbeck Gerhard
Published: December 2011

Mit Hilfe der vergleichenden Bilanzierung der Nitrat‐ und Chloridgehalte in ihrer Tiefenverteilung auf wiederholt beprobten Ackerstandorten tiefgründiger Lößsedimente in Süddeutschland wurde versucht, Nitratverluste durch Denitrifikationsvorgänge in tieferen Bodenschichten zu ermitteln. Das Ausmaß der Nitratverluste in der Dränzone war abhängig von der Nitratkonzentration im Bodenwasser. Bei sehr hohen Nitratkonzentrationen ergaben sich hohe Denitrifikationsraten bis zu 0.5 kg NO3−N/(ha·d·0.33 m). Eine vollständige Nitrat‐eliminierung fand jedoch in keinem Fall statt. Der Profilaufbau im tieferen Untergrund bot günstige Bedingungen für Denitrifikationsprozesse durch geringe luftführende Porenanteile. Als Quellen für mikrobiell oxidierbare Substrate konnten erhöhte Corg−Gehalte im Bereich einer interstadialen Bodenbildung (Würm) sowie reduzierte Schwefelverbindungen im Würmlöß nachgewiesen werden.
Seasonal dynamics of active soil carbon and nitrogen pools under intensive cropping in conventional and no tillage
Authors: Franzluebbers Alan J. , Hons Frank M. , Zuberer David A.
Published: December 2011

Active fractions of soil carbon (C) and nitrogen (N) can undergo seasonal changes due to environmental and cultural factors, thereby influencing plant N availability and soil organic matter (SOM) conservation. Our objective was to determine the effect of tillage (conventional and none) on the seasonal dynamics of potential C and N mineralization, soil microbial biomass C (SMBC), specific respiratory activity of SMBC(SRAC), and inorganic soil N in a sorghum [Sorghum bicolor (L.) Moench]‐wheat (Triticum aestivum L.)/soybean [Glycine max (L.) Merr.] rotation and in a wheat/soybean double crop. A Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas was sampled to 200 mm depth 57 times during a 2‐yr period. Potential C mineralization was lowest (≈︁2 to 3 g · m−2 · d−1) midway during the sorghum and soybean growing seasons and highest (≈︁3 to 4 g · m−2 · d−1) at the end of the wheat growing season and following harvest of all crops. Addition of crop residues increased SMBC for one to three months. Potential N mineralization was coupled with potential C mineralization, SRAC, and changes in SMBC at most times, except during the wheat growing season and shortly after sorghum and soybean residue addition when increased N immobilization was probably caused by rhizodeposition and residues with low N concentration. Seasonal variation of inorganic soil N was 19 to 27%, of potential C and N mineralization and SRAC was 8 to 23%, and of SMBC was 7 to 10%. Soil under conventional tillage experienced greater seasonal variation in potential C and N mineralization, SRAC, bulk density, and water‐filled pore space than under no tillage. High residue input with intensive cropping and surface placement of residues were necessary to increase the long‐term level of active C and N properties of this thermic‐region soil due to rapid turnover of C input.
Response of rice to basic slag, lime, and leaching in two saline‐acid sulfate soils in pot experiments
Authors: Khan H. R. , Rahman S. , Hussain M. S. , Blume H.‐P.
Published: December 2011

Pot experiments were conducted to evaluate the effects of basic slag (6 to 18 t/ha), lime (CaCO3: 3 to 9 t/ha), lime (3 t/ha) plus MnO2 (100 mg/kg), and leaching (1.8 L/kg soils) on the growth, yield, and nutrition of rice plants grown on two saline‐acid sulfate soils. The Sulfic Fluvaquent (Chakaria series) and Typic Sulfaquent (Badarkhali series) respectively showed low pH (4, 4.3); high electrical conductivity (16.2, 14.2 mS/cm), sodium adsorption ratio (13.6, 12.8), and water soluble SO42− (4.6, 4.9 cmol/kg).

The growth and yield response of rice to the treatments were found better in Chakaria than in Badarkhali soil. The leaching treatment was found to be the best to produce the maximum straw, and grain yield (869% increase over the control) and the highest dose of basic slag (18 t/ha) was ranked second (728%) in Badarkhali soil. But in Chakaria soil, the best response (928%) was determined with the highest dose of lime (6 t/ha) followed by the leaching (900%) treatment. The additional application of Mn02 (100 mg/kg) with lime (3 t/ha) significantly increased the straw and grain yields of rice by 42–47% compared with the lime 3 t/ha in both the soils. Similar effects were observed for N, P, and K concentrations in plant straw at maturity. Leaching, basic slag, and lime treatments exerted significant decrease of the Fe, Mn, Zn, and S concentrations in plants, increase of soil solution pH and optimization of some element concentrations in the plants and soil solutions.
Förderung des Wachstums und der Nährstoffaufnahme bei kruziferen Ölund Zwischenfrüchten durch inokulierte Rhizosphärenmikroorganismen
Authors: Höflich Gisela , Kühn Günter
Published: December 2011

Das vegetative Wachstum von Raps, Ölrettich und Senf wurde in Gefäß‐ und/bzw. Feldversuchen mit Isolaten von Pseudomonas fluorescens (PsIA12), P. putida (AI A2), Stenotrophomonas maltophilia (PsIB2, PsI2). Agrobacterium rhizogenes (A1A4) und Rhizobium trifolii (R39) durch stimulierte Wurzelentwicklung und Nährstoffaufnahme (N, P. K, Mg) auf lehmigem Sand und sandigem Lehm bei unterschiedlichem Ertragsniveau wiederholt gefördert.

Der Samenertrag von Raps konnte nur durch 2 Isolate (PsIA12, PsIB2) erhöht werden. Die wachstumsfördernden Bakterien bildeten Phytohormone (Auxine und z.T. Cytokinine). Zwischen Pflanzen‐ wachstumstimulierung und den potentiellen mikrobiellen Stoffwechselleistungen z.B. Nitrogenase, Nitratreduktase, P‐Mobilisierung, Pektinase, Zellulase zeichneten sich keine direkten Beziehungen ab. Wirksame Bakterien gehen mit Pflanzen eine enge Assoziation ein und können in der Rhizosphäre überleben.
Einfluß des Belastungsgrades unterschiedlicher Böden an ausgewählten Pestizid wirkenden Chlorkohlenwasserstoffen auf deren Aufnahme durch Möhren im Gefäßversuch
Authors: Heinrich Kathrin , Schulz Elke
Published: December 2011

Beispielhaft wurden Böden aus Gebieten mit geringer bis hoher Belastung an ausgewählten Pestizid wirkenden Chlorkohlenwasserstoffen (CKW) für einen Gefäßversuch zur Aufnahme dieser Xenobiotika durch Möhrenpflanzen eingesetzt.

Möhren sind in der Lage, pestizid wirkende CKW aufzunehmen, was auf Grund ihrer Ölzellen und der Lipophilie der zu untersuchenden Substanzen erwartet wurde. Ist ein Boden hoch mit diesen Substanzen belastet, so wird auch entsprechend mehr in die Pflanzen aufgenommen als aus nicht bzw. gering belasteten Böden. Trotz der hoben Konzentrationen an beta‐ und alpha‐HCH in den Pflanzen in der Variante Muldenaue war die Summe der Pflanzenaufnahme pro Gefäß relativ gering (unter 2 mg/Gefäß). Bei der Bestimmung der mittleren Transferfaktoren Boden/Pflanze konnte für die gesamte Pflanze (Sproß 0.021 < Möhrenkörper 0.156 < Feinwurzel 0.975) trotz der zum Teil sehr hohen Schadstoffkonzentrationen im Boden keine Anreicherung der untersuchten Organochlorpestizide in der Variante Muldenaue beobachtet werden.
Eigenschaften von Böden unterschiedlicher Nutzung im Stadtgebiet von Rostock
Authors: Kahle Petra , Coburger Ellen
Published: December 2011

Mit dem Ziel einer Stadtbodenkartierung werden in Rostock umfangreiche Untersuchungen zum Vorhandensein, der Genese und den Eigenschaften anstehender natürlicher und anthropogen beeinflußter Böden durchgeführt. Im vorliegenden Beitrag werden ausgewählte chemische und physikalische Eigenschaften von Böden der Nutzungstypen Garten, Park, Friedhof und Wohnbebauung der Stadt vorgestellt und diskutiert. Hervorzuheben sind die positiven Beeinflußungen des pH‐Wertes bei Wohnbebauungen im Kernstadtgebiet, die tiefgründigen Humusanreicherungen bei Gartennutzung und die Tendenzen zur Bodenversauerung in den sandigen Parkböden.
The variability between different analytical procedures and laboratories for measuring soil microbial biomass C and biomass N by the fumigation extraction method
Authors: Joergensen Rainer Georg , Olfs Hans‐Werner
Published: December 2011

The interlaboratory variations in the fumigation extraction method and the analytical procedures for measuring C and N in the soil microbial biomass were tested with one soil sample, and two soil extracts (non‐fumigated and fumigated) sent to 25 different laboratories. Four groups of analytical procedures for organic C, i.e. (1) oven oxidation/ IR detection, (2) UV‐persulfate oxidation/lR detection, (3) UV‐persulfate oxidation/colorimetric detection and (4) dichromate oxidation/ titration, and three groups for total N, i.e. (1) Kjedahl reduction to NH4+, (2) UV‐persulfate and (3) persulfate‐borate oxidation to NO3− were used by the different laboratories.

The coefficient of variation for C and N measurements between different laboratories and analytical procedures varied between 15 and 34% in non‐fumigated samples, between 13 and 20% in fumigated samples, and between 12 and 24% in the differences Ec and EN. The average coefficients of variation between the replicate measurements within one laboratory were much smaller, i.e. they varied between 3.0 and 9.2% in non‐fumigated samples, between 2.4 and 5.5% in fumigated samples, and between 4.5 and 12.8% in the differences Ec and En. Extraction and fumigation were not the major source of the variations observed. They were mainly a result of differences in the analytical procedures used to measure the low concentrations of C and N in the extracts. However, all of these analytical procedures should be able to measure correct values if they are properly calibrated and performed.
Investigating sulfate sorption and desorption of acid forest soils with special consideration of soil structure
Authors: Alewell Christine
Published: December 2011

When investigating the reversibility of soil and water acidification due to a reduction of SO42− deposition, the size and stability of the reversibly bound SO42− fraction in soils are important parameters. The desorption behaviour of SO42− in three acid forest soils was investigated using columns with undisturbed and disturbed (< 5 mm sieved) soil material. The results were compared to batch experiments.

A comparison of the undisturbed and the disturbed soil samples showed that the soil structure had no effect on the chemistry of the soil solution, the S‐mineralisation rates or the SO42− desorption rates. A comparison of the batch and the column method showed only minor differences in desorption rates. However, fitting the measured desorption rates to a modified Langmuir equation showed a more distinct difference between both methods. It was concluded that the batch method was more suitable to establish SO42− desorption isotherms.

When investigating SO42− dynamics of soils, the heterogeneity of the soils has to be considered because the spatial variability of isotherm parameters was found to be greater than differences between the investigated methods. Furthermore, SO42− sorption showed a distinct hysteresis. While most of the sorbed SO42− was desorbed at concentrations < 5–10 mg SO42 −1−1, a sorption of SO42− was observed only at concentrations > 20–30 mg SO42− ·1−1.
Element contents of perennial plant species in the sand desert near Nizzana (Israel)
Authors: Bornkamm Reinhard , Darius Frank , Prasse Rüdiger
Published: December 2011

In the arid sand dune ecosystem of Nizzana, northwestern Negev, Israel, three perennial species were investigated for concentrations of the elements C, N, S, P, Ca, Mg, K, Na and Cl. From the dune tops (crests) to the dune valleys six different ecotopes (habitats) were discerned where the sampling took place. The soil conditions are known due to previous investigations of H.‐P. Blume and his coworkers. The species Anabasis articulata and Cornulaca monacantha (both Chenopodiaceae) showed considerable variation of element contents according to the ecotopes. In some ecotopes of the dune valleys they showed higher contents of sodium and chloride than in the ecotopes of the proper dune, and by Na/K ratios of > 1 they indicated slightly halophytic character. The glycophyte Thymelaea hirsuta (Thymelaeaceae) exhibited very low element concentrations which practically did not change between the ecotopes. The conclusion was drawn that Thymelaea is characterized by a higher selectivity of ion uptake than the two other species.
Starch deposition in storage organs and the importance of nutrients and external factors
Authors: Kosegarten Harald , Mengel Konrad
Published: December 2011

Starch is an important agricultural product deposited in vegetative and reproductive storage organs (sinks) of various crop species. Starch yield may in some cases be limited by photosynthesis, i.e. source‐limited. This is particularly true for starch synthesized in potato tubers. Here, the physiological sink is characterized by a symplastic phloem unloading path. In reproductive storage tissues (seeds), however, photosynthates must pass the apoplast on their path from phloem unloading to the storage cell. In cereal grains, phloem unloading of sucrose and poslunloading processes rather than photosynthesis may thus control starch synthesis (sink‐limited). Various limiting steps along the path of photosynthate movement from the phloem to the storage cells are considered.

The primary organic carbon for starch synthesis is sucrose. Sucrose delivered to the storage cell is metabolized to UDPglucose and fructose by means of sucrose synthase activity. Concerning sucrose breakdown the role of cell‐wall bound invertase is not well defined. Competition for UDPglucose consumed for growth or storage may be a crucial process in photosynthate partitioning. High starch yields of crops require an undisturbed growth of the sink organ and an optimal filling of sink amyloplasts with starch. The most important form of organic carbon imported into amyloplasts of storage organs (cereal grain and potato tuber) and used for starch synthesis is glucose 1‐phosphate. It is still to be clarified whether the rate of glucose 1‐phosphate absorption has a direct impact on starch yield.

In cereals, the total amount of starch accumulated depends significantly on the duration of grain filling. Ample nutrient and water supply at the post‐anthesis stage prolongs the period of grain filling and hence favours starch production. High temperature reduces the activity of soluble starch synthase with negative consequences for starch accumulation. The biochemical and physiological implications of these stress factors are discussed. Recently, successful transgenic manipulations of starch synthesis in crop plants have increased starch yield.
Agricultural nitrogen, phosphorus and potassium balances in Germany —Methodology and trends 1970 to 1995
Authors: Bach Martin , Frede Hans‐Georg
Published: December 2011

The nitrogen, phosphorus and potassium balances for agriculture in Germany during the period 1970 to 1995 (western states) and 1990 to 1995 (entire Germany including the states of the former German Democratic Republic), respectivly, are calculated according to the PARCOM guidelines. The surplus of the basic national mineral balance is subdivided into the crop production surplus and the livestock production balance surplus. In the former West German states, P and K basic surpluses have declined about 60% since 1980, while the N‐surplus has dropped 23% since 1987. The efficiency of agricultural nutrient use has improved correspondingly. A sensitivity analysis and an error estimation reveal the accuracy of the results. The relevance and limits of interpreting nutrient balances on a national scale are clarified by a critical appraisal of the balance surplus values.
Prediction of mineralizable nitrogen in soils on the basis of an analysis of extractable organic N
Authors: Appel Thomas , Mengel Konrad
Published: December 2011

Most of the nitrogen (N) in agricultural soils is organically bound, while the N uptake by plants and also the N losses from the soil‐plant system into the environment are as inorganic N. The electro‐ultrafiltration (EUF) method and the extraction by a CaCl2 solution extract an organic N fraction (Norg) that is thought to provide information about the amount of rapidly mineralizable N in soils. This paper aims to illustrate various aspects regarding the biological meaning of the Norgfractions extracted by these two extraction methods and also the opportunities and limitations for predicting the mineralizable N based on an Norg analysis.

From an evaluation of numerous data on EUF and CaCl2 extract‐able Norg fractions we concluded that these methods extract N compounds which can be used as indices for easily mineralizable soil N. However, both methods extract only some of the rapidly mineralizable N in soils, and some of the Norg ecxtracted appears to be from the more recalcitrant soil organic N. This was particularly true for the EUF‐method. It may therefore be desirable to improve both the extractability and the selectivity of the extraction methods. This may be achieved by measuring extractable amino‐N compounds instead of the total extractable Norg.

Evaluating the numerous field experiments done during the last decade shows that the calibration factors obtained for extractable Norg were not the same for different growing seasons, geographical regions and management practices. Theoretically, for each combination of these factors separate calibrations would be necessary. It is this inflexibility which appears to be the most serious drawback for the use of extractable Norg fractions in practice.

A possible solution may be to combine the flexibility of a simulation model with additional information obtained by the analysis of extract‐able soil organic N. Further work in this direction may be desirable.
Use of a coupled equilibrium model to describe the buffering of protons and hydroxyl ions in some acid soils
Authors: Ludwig Bernard , Khanna Partap , Prenzel Jürgen
Published: December 2011

The buffering of protons and hydroxyl ions in acid soils was studied by the addition of small amounts of HCl, H2SO4, and NaOH in consecutive batch experiments using surface soils and subsoils from two Cambisols and one Podzol. A chemical equilibrium model was used to study the main buffer processes. The model included inorganic complexation and multiple cation exchange, and also the solubility of jurbanite and Al(OH)3 for the subsoils.

Buffering of protons was predicted quite well by the model for the surface soil of the Spodi‐Dystric and Spodic Cambisols, suggesting that multiple cation exchange was the main buffer process. For the Podzol surface soil, however, the model overestimated proton buffering by cation exchange considerably. Hydroxyl buffering in acid surface soils could be described well by the model for the Podzol soil only. For the Cambisols, hydroxyl buffer reactions included not only cation exchange, but also solubilization of large amounts of organic matter and presumably deprotonation of dissolved organic carbon (DOC).

Modelling proton and hydroxyl buffering in subsoils suggested that equilibrium with AJ(OH)3 was not maintained for the Podzol and spodic Cambisol. Sulphate sorption had to be considered to describe titration experiments in all three soils. The assumption of jurbanite being in equilibrium with soil extracts was useful only for the Spodi‐Dystric Cambisol.
Abbau von Huminstoffen durch Bodenmikroorganismen — eine Übersicht
Authors: Filip Zdenek , Claus Harald , Dippell Gerald
Published: December 2011

Huminstoffe als die unterschiedlich extrahierbaren Fraktionen der organischen Bodensubstanz beeinflussen auf vielseitige Weise die Qualität des Bodens als Pflanzenstandort und Bestandteil der Umwelt. Insbesondere Huminsäuren und Fulvosäuren können biologischen Umsetzungen durch die Bodenmikroorganismen unterliegen. Von vielen Autoren wurde die Beteiligung unterschiedlicher Spezies von Pilzen und Aktinomyceten sowie von nichtmyzelartigen aeroben und anaeroben Bakterien am Ab‐ und Umbau von Huminstoffen unter Laborbedingungen nachgewiesen. Es gibt mehrere Hinweise auf einen strukturspezifischen Huminstoffabbau, der auf Zelloberflächen unter Beteiligung von Exoenzymen stattfindet. Die herausragende Rolle phenoloxidierender Enzyme bei diesen Prozessen konnte bestätigt werden. Der Abbau der Huminstoffe wird optisch, gravimetrisch, chemoanalytisch, biochemisch (CO2−Freisetzung) oder biologisch anhand des Mikrobenwachstums bzw. der Biomassebildung verfolgt. Seine quantitative Erfassung kann durch die Adsorption der Huminstoffe an der Mikrobenbiomasse einerseits und durch die Neubildung huminstoffähnlicher Stoffwechselprodukte andererseits erschwert werden. Es ist daher notwendig, den Abbau‐ und Umbauprozeß mehrfaktoriell zu verfolgen und gleichermaßen quantitative wie auch qualitative Parameter zu berücksichtigen. Um den natürlichen Standortbedingungen näher zu kommen, sollen Mischpopulationen von Mikroorganismen in die Untersuchungen des Huminstoffabbaus verstärkt einbezogen werden.
Magnesium‐ und Calcium‐Ernährung von Hochlagenfichten —Vergilbungszustand und Reaktion auf unterschiedliche Düngung
Authors: Gülpen Martin , Feger Karl‐Heinz
Published: December 2011

Auf den ARINUS‐Versuchsflächen im Schwarzwald wurden seit 198V Untersuchungen zum Mincralstoffhuushult der aufstockenden Fichtenbestände mit unterschiedlicher experimenteller Düngung durchgeführt. Hierbei stand das Nährelement Mg im Vordergrund, da auf den Flächen zu Beginn der Untersuchungen Symptome der “montanen Vergilbung der Fichte” (akuter Mg‐Mangel) zu beobachten waren. Die erfolgten Behandlungen mit Ammonsulfat, Kieserit und Dolomit hatten eine experimentelle Beeinflussung der Mg‐Ernährung zum Ziel. Im Rahmen dieser Arbeit werden Ergebnisse zum Vergilbungszustand, zur langfristigen Entwicklung der nadelanalytisch belegten Bestandesernährung, sowie zu den Bindungsformen von Ca und Mg in Nadeln und im Holz vorgestellt. Durch Gaben Mg‐haltiger Düngemittel wurde die Mg‐Versorgung der Fichten deutlich verbessert und eine Wiederergrünung der vergilbten Bestände erreicht. Die Kieseritgabe erbrachte hierbei die schnellste Verbesserung der Mg‐Versorgung. Im Gegensatz zu Mg konnte bei Ca kein Mangel festgestellt werden. Die Ergebnisse der (NH4)2SO4−Gaben zeigen, daß hohe N‐Einträge latente Mineralstoffmängel, z.B. von Mg, verstärken können. Durch die depositionsbedingt verbesserte N‐Verfügbarkeit ist gegenwärtig auf vielen Standorten ein erhöhtes Risiko von Ernährungsungleichgewichten gegeben. Um dem wirkungsvoll zu begegnen, sollten Kalkungcn bzw. Düngungen nährelemenl‐ und standortspezifische Aspekte stärker berücksichtigen. Zur langfristigen Sicherstellung der Bestandesernährung sind die tieferwurzelnden Baumarten Buche und Tanne waldbaulieh stark zu fördern.