bluuebunny/crossref_metadata_2025 huggingface dataset:
Hepatitis C virus genotyping in Greece: Unexpected high prevalence of genotype 5a in a Greek island
Authors: Karatapanis Stylianos , Tsoplou Panagiota , Papastergiou Vasilios , Vasiageorgi Aggeliki , Stampori Maria , Saitis Ioannis , Tsitsopoulos Eustathios , Lisgos Phillipos , Skorda Lamprini , Ketikoglou Ioannis , Goulis Ioannis
Published: December 2011

Hepatitis C virus (HCV) genotype 5 (G5) is a rare genotype reported mainly in South Africa. However, increasing data suggest the sporadic presence of this genotype in different European countries. To assess the epidemiology of HCV‐G5 in Greece, genotyping was performed in 973 consecutive patients infected with HCV, referred to 7 hepatology centers throughout Greece, from January 2005 to December 2009. Genotype 5a (19 patients, 1.9%) was the fifth most prevalent genotype after genotype 1 (408 patients, 41.9%), genotype 3 (318 patients, 32.7%), genotype 4 (158 patients, 16.2%), and genotype 2 (70 patients, 7.2%). The majority of patients infected with G5 (16/19,84.2%) were referred to the General Hospital of Rhodes, an island in south‐east Greece. The HCV genotype distribution in that particular island, indicates a particularly high G5 prevalence of 12.8%, after genotype 1 (40%), genotype 3 (28%), and genotype 4 (15%). Among the patients from Rhodes infected with G5 (n = 16), 13 (81.2%) were females. The mean age was 62.3 ± 6.5 years, significantly older than the patients infected with other HCV genotypes (mean age 40.6 ± 7.2, P < 0.0001). Nine out of the 16 cases (56.2%) presented features of high pre‐treatment viral loads. Advanced liver fibrosis (Metavir F3–F4) was found in four out of five performed liver biopsies. Ten patients received treatment with pegylated interferon plus ribavirin and a sustained viral response were achieved in six cases. The source of infection is unknown but parenteral iatrogenic routes of transmission seem to have contributed significantly to the spread of genotype 5a in this region. J. Med. Virol. 84:223–228, 2012. © 2011 Wiley Periodicals, Inc.
Human bocavirus infection diagnosed serologically among children admitted to hospital with community‐acquired pneumonia in a tropical region
Authors: Nascimento‐Carvalho Cristiana M. , Cardoso Maria‐Regina A. , Meriluoto Mira , Kemppainen Kaisa , Kantola Kalle , Ruuskanen Olli , Hedman Klaus , Söderlund‐Venermo Maria
Published: December 2011

Human bocavirus (HBoV) is a human virus associated with respiratory disease in children. Limited information is available on acute infection with HBoV among children admitted to hospital with community‐acquired pneumonia in tropical regions and the current diagnosis is inadequate. The aims were to diagnose and describe acute HBoV infections among children hospitalized for community‐acquired pneumonia. In Salvador, Brazil, 277 children with community‐acquired pneumonia were prospectively enrolled. Paired serum samples were tested by IgG, IgM, and IgG‐avidity enzyme immunoassays (EIAs) using recombinant HBoV VP2. HBoV DNA was detected in nasopharyngeal aspirates and serum by a quantitative polymerase‐chain reaction (PCR). HBoV DNA was detected in nasopharyngeal aspirates of 62/268 (23%) children and 156/273 (57%) were seropositive. Acute primary HBoV infection was reliably diagnosed (bearing at least two acute markers: Positive IgM, a fourfold increase/conversion of IgG, low IgG avidity or viremia) in 21 (8%) of 273 patients, 90% of 20 had HBoV DNA in nasopharyngeal aspirates, 83% with a high DNA load. The median age of infection with HBoV was 16 months, range 5–36. Community‐acquired pneumonia was confirmed radiographically in 85% of 20 patients with acute HBoV infection diagnosed serologically. HBoV DNA was found in nasopharyngeal aspirates of 42/246(17%) children without an acute primary HBoV infection and available nasopharyngeal aspirate. Four children with HBoV secondary immune responses were detected, lacking both IgM and viremia. HBoV infection was diagnosed accurately in children aged 5–36 months with community‐acquired pneumonia confirmed radiographically. PCR of nasopharyngeal aspirates is not a reliable marker of acute HBoV infection. J. Med. Virol. 84:253–258, 2012. © 2011 Wiley Periodicals, Inc.
Seroepidemiology of WU polyomavirus among children exposed perinatally to HIV‐1
Authors: Miller Michael A. , Weibel Carla , Kahn Jeffrey S. , Andiman Warren A.
Published: December 2011

WU polyomavirus (WUPyV), a new member of the genus wukipolyomavirus in the family Polyomaviridae, has been detected in serum and tissues of individuals infected with HIV. However, the epidemiology of WUPyV among children exposed perinatally to HIV‐1 is unknown. To investigate the epidemiology of WUPyV in children exposed to and infected perinatally with HIV, serum samples from 150 children exposed to HIV and 114 children infected with HIV were screened for IgG antibodies to WUPyV. A subset was screened for IgM antibodies to WUPyV. Both antibody detection assays were performed using a recombinant WUPyV VP1‐based ELISA. The overall seroprevalence of WUPyV IgG was 76.3% in children infected with HIV and 62% in children exposed perinatally to HIV. In the group of children infected with HIV, the prevalence of WUPyV IgG antibody reached its peak in 2–3 year olds (90.9%). In children 0–5 months of age, IgG seroprevalence was lower in those children exposed to HIV compared to children infected with HIV (43.1% vs.75%, P = 0.047). However, the seroprevalence of WUPyV IgM antibody was higher in children exposed to HIV compared to infants infected with HIV (27.4% vs. 8.3%, P = 0.044). WUPyV infection is acquired in early childhood in the majority of children born to mothers infected with HIV. The implication of this infection and the specific clinical syndrome that it produces, if any, remain to be defined. J. Med. Virol. 84:188–193, 2012. © 2011 Wiley Periodicals, Inc.
Increased replication of respiratory syncytial virus in the presence of cytokeratin 8 and 18
Authors: Shirato Kazuya , Ujike Makoto , Kawase Miyuki , Matsuyama Shutoku
Published: December 2011

Previously, it was reported that productive viral infection, viral protein synthesis, and viral RNA replication of respiratory syncytial virus (RSV) operated efficiently in two human epithelial cell lines (HEp‐2 and A549), but not in a human mast‐cell line, HMC‐1. Based on these observations, it was hypothesized that HMC‐1 cells lack the machinery required for RSV replication. To identify the host factors required for RSV replication, cDNA subtraction using A549, HEp‐2, and HMC‐1 cells was performed, and cytokeratin 18 (C18) was identified as a candidate host factor. Because C18 is generally expressed in simple epithelia with cytokeratin 8 (C8), HMC‐1 cells that constitutively express C18 and C8 (HMC‐1‐C8/18) were established to evaluate the role of C8/18 in RSV replication. In HMC‐1‐C8/18 cells, RSV RNA replication was increased, and the amount of infective virus produced was also increased in the cellular fraction after RSV spinoculation, whereas RSV production was decreased in A549 cells in which C18 expression was knocked down. These data suggest that the replication of RSV increases in the presence of C8/18. J. Med. Virol. 84:365–370, 2012. © 2011 Wiley Periodicals, Inc.
Arbuscular mycorrhizal fungi‐induced alteration to tree‐root architecture and longevity
Authors: Hooker John E , Atkinson David
Published: December 2011

Arbuscular mycorrhizal fungi (AMF) form mutualistic associations with most terrestrial plants, including trees. They can confer many benefits and are known to induce widespread changes in host plant physiology. For many years it was considered that colonisation by AMF did not alter root architecture but significant alteration has now been demonstrated unequivocally for several plants, including trees with AMF colonised plants usually possessing a more highly branched root system. More recently, alteration to root system longevity has also been measured with AMF colonised root systems being shorter lived. Mechanisms by which these changes occur are not understood but effects are not entirely due to altered phosphorus nutrition and are likely to involve AMF interaction with plant cell cycles. Future research should concentrate on defining the extent of AMF alteration to root system development and the importance of AMF interactions with plant cell cycles in determining these changes.
Phosphorus fractions in soils from an area with high density of livestock population
Authors: Leinweber Peter
Published: December 2011

The concentrations of total phosphorus and its distribution in fractions of different solubility have been investigated in 6 different organic manures and in 69 soil samples from two counties with high concentrations of livestock population (Cloppenburg and Vechta, Lower Saxony). In the manures, large proportions of total P (means: 24% and 44%) were extracted by H2O and anion exchange resin so that increases in labile soil P fractions can be expected if these manures are applied. The high total P‐concentrations of the soils up to 8173 mg kg−1 were related to pedogenesis and soil use. Data such as soil P test (H2O‐P, DL‐P) values above the P‐fertilizer recommendations and considerably larger proportions of soluble and labile P‐fractions (7%‐47% of total soil P) than in other regions strongly suggested that significant P‐losses from the soils are likely. Therefore, reductions of P inputs to soils and measures to reduce the P‐solubility and mobility are necessary for water conservation in this region.
Höhe der Erhaltungsdüngung und Ausnutzung von Düngerphosphat vor dem Hintergrund der P‐Alterung im Boden
Authors: Jungk Albrecht , Wendt Joachim , Claassen Norbert
Published: December 2011

Düngerphosphat, auch wasserlösliches, wird von Ackerpflanzen im Jahr der Anwendung meist zu weniger als 20% ausgenutzt. Seine Löslichkeit nimmt mit zunehmender Verweilzeit im Boden kontinuierlich ab, ein Prozeß, der als Alterung bezeichnet wird. Diese P‐Bindung hat zu der verbreiteten Ansicht geführt, ein Teil des Düngerphosphats gehe in eine pflanzenunverfügbare Form über und werde daher nicht vollständig ausgenutzt. Wenn dies zuträfe, dann müßte die P‐Düngung ständig größer als die P‐Abfuhr sein, um die P‐Versorung auf dem gleichen Niveau zu halten. In langfristigen Feld‐ und Gefäßversuchen mit verschiedenen Böden wurde der Frage nachgegangen, ob dies zutrifft. Die Ergebnisse zeigen, daß die P‐Gehalte des Bodens, gemessen mit der DL‐, der CAL‐ und der P‐H2O‐Methode, über längere Zeit nahezu unverändert blieben, wenn die P‐Düngung der P‐Abfuhr entsprach. Eine Tendenz zur Abnahme des leichtlöslichen Phosphats war nur zu beobachten, wenn der P‐Gehalt des Bodens den P‐Bedarf der Pflanzen weit überstieg. Eine Düngungshöhe unter bzw. über der Abfuhr führte dagegen zur Abnahme bzw. Zunahme der P‐Gehalte des Bodens bei Messung mit den oben genannten Methoden. An einem langfristigen Feldversuch ergab sich, daß bei P‐Düngung in Höhe der P‐Abfuhr auch der in einer Woche desorbierbare P‐Anteil des Bodens konstant blieb. Im Überschuß über den Entzug gedüngtes P ging dagegen in eine Form über, aus der es kurzfristig nicht vollständig desorbiert wird. Das nach den Labormethoden als festgelegt erscheinende Phosphat steht jedoch den Pflanzen längerfristig zur Verfügung. Aus den Versuchsergebnissen wird der Schluß gezogen, daß die “P‐Alterung” im Boden keinen Verlust für die Pflanze darstellt. Düngerphosphat ist demnach vollständig nutzbar, so daß eine P‐Gabe in Höhe der P‐Abfuhr vom Feld als Erhaltungsdüngung ausreichend ist.
Basic strategies of molecular biological research in plant nutrition ‐ a review
Authors: Arnholdt‐Schmitt Birgit
Published: December 2011

A review is given on basic methodical strategies of molecular biological research in plant nutrition. Membrane transport protein identification and analysis by the use of cDNA libraries and functional expression in yeast mutants and Xenopus oocytes is demonstrated. The various methods of gene isolation and analysis, including molecular data of model plants, are pointed out. The significance of research on transgenic plants permitting overexpression of introduced genes, antisense technique and analysis of promoter/reporter gene constructs is emphasized. The numerous examples of recent research simultanously indicate contemporary and future topics for molecular biological research in plant nutrition.
Solubility of soil phosphorus as influenced by urea
Authors: Hartikainen Helinä , Yli‐Halla Markku
Published: December 2011

The objective of this study was to investigate possible ways of mobilizing residual fertilizer P as a result of local pH elevation caused by urea hydrolysis. The response of water‐soluble P (Pw) and dissolved organic C (DOC) to urea hydrolysis was monitored in three cultivated soils and at two P levels for up to 127–135 d and compared with corresponding changes in soils limed with Ca(OH)2. Hydrolysis of urea was complete in 8–15d during which soil pH increased by 1–1.5 units at the maximum. Subsequently, the pH decreased to or below the original level owing to nitrification. Mobilization of soil P was enhanced substantially in parallel with the increase in pH, the peak Pw occurring simultaneously with the highest pH value. In all urea‐treated soils, Pw remained at an elevated level for at least 60d. As compared to urea, elevation of soil pH with Ca(OH)2 had only a minor and inconsistent influence on Pw. In mobilization of soil P, the urea‐induced increase in pH and a simultaneous production of NH4+ ions proved to be superior to liming with Ca(OH)2. It was hypothesized that when an acid soil is amended with urea, phosphate is first displaced by OH− ions, resulting in elevated solution P concentrations. A simultaneous dissolution of organic matter contributes to the persistence of high P concentration by competition for sorption sites on Fe and Al oxides, and thus retards the resorption of P.
Seasonal and spatial variation of extractable trace metal fractions in topsoils under mixed forest
Authors: Wenzel Walter W. , Alge Guntram , Blum Winfried E. H. , Brandstetter Anton , Pollak Michael A. , Riedler Christian , Schulte Andreas
Published: December 2011

Metal extractability from soils may be affected by analytical errors, sample preparation, inaccurate sampling as well as by natural variation in space and time. During one year, we sampled the Ah horizons of a forested Luvi‐Calcaric Cambisol from 43 subplots in a visually homogeneous area of 0.5 ha six times to determine the spatial and seasonal variation of pH, OC, and Fe, Mn, Cr, Cu, Ni, Pb and Zn extractable by 0.1 M BaCl2 and 0.05 M Na2ETDA. As indicated by a two‐way ANOVA, the spatial and seasonal variations of all parameters were significant at p < 0.01. The metal‐specific ranges of seasonal variation varied between 21% and 90% of the minima for Na2EDTA, and 15% and 71% for 0.1 M BaCl2. The error due to within‐subplot variability and inaccurate sampling, tested by sampling twice in April 1992, was small compared to the natural seasonal and spatial variation. The relative differences between the means of the two samplings tended to increase with the coefficients of spatial variation, suggesting an increasing contribution of within‐subplot variability to the sampling error. The study shows that both spatial and seasonal variation of extractable metal fractions may bias the analysis of mobile metal fractions in a rarely predictable way.
Die Bedeutung amorpher AI‐Verbindungen für Al‐Freisetzungsraten in carbonatfreien, sandigen Böden
Authors: van de Sand Martina , Fischer Walter R.
Published: December 2011

In einer vorangegangenen Arbeit war mit Hilfe von pH‐stat‐Versuchen die Kinetik der Protonenpufferung und der Elementfreisetzung in carbonatfreien, sandigen Waldbodenhorizonten untersucht worden. Die freigesetzten Elemente Al und DOC sollten nunmehr als äquivalente Verluste in der Bodenfestphase nachgewiesen werden, und durch unterschiedliche Extraktionsverfahren (Lichterfelder: Corg; Pyrophosphat‐Extraktion: Alp, Corg‐p; Oxalat‐Extraktion: Alo) sollten die Hauptpools der Stoffmobilisierung bei Säurebelastung bestimmt werden. In acht der zehn untersuchten Horizonte bedingte die Al‐Freisetzung eine entsprechende Abnahme an organisch gebundenem Al (Alp), in vier davon ließen sich gleichzeitig Verringerungen der Corg‐p−Gehalte in Höhe des gelösten DOC nachweisen. Für die beiden anderen Horizonte konnte die Al‐Mobilisierung etwa je zur Hälfte auf die Auflösung organischer und anorganischer amorpher Al‐Verbindungen zurückgeführt werden. Wie bereits die Freisetzung an Al und DOC ließen sich auch die Verluste an Alp, Alp, und anorganischem Al (Alo−Alp) als Reaktionen 1. Ordnung darstellen, die Auflösungsgeschwindigkeiten [h−1] an Alp (0.027), Alo (0.023) und Corg‐p (0.026) entsprachen der Freisetzung an Al (0.027) bzw. DOC (0.024). Für die Auflösung anorganischer Al‐Verbindungen wurden mit 0.066 bzw. 0.052 etwa doppelt so hohe Geschwindigkeitskonstanten errechnet.
Organic phosphorus species in humic acids of mountain soils along a toposequence in the Northern Caucasus
Authors: Makarov Mikhail I. , Guggenberger Georg , Zech Wolfgang , Alt Helmut G.
Published: December 2011

Organic P was investigated in humic acids extracted from mountain soils developed in the subalpine, upper subalpine and alpine zones of the Northern Caucasus. P contents of humic acids varied between 3.4 and 14.2 g P kg−1, depending on P contents of the parent vegetation and on site conditions. Organic P was accumulated at sites where microbial activity is restrained due to soil acidity, low soil temperature and hydromorphy.31 P NMR spectroscopy revealed that orthophosphate monoesters were the dominent P species (72–85% of extract‐ able P), orthophosphate diesters amounted to 12–21%, and phospho‐ nates ranged between 0 and 9%. Humic acids of soils under cold and wet climatic conditions showed highest concentrations in phospho‐ nates and orthophosphate diesters. Hence, the accumulation of organo‐P in the Caucasian mountain soils was partly due to increasing proportions of potentially available organic P species.
What predicts nitrous oxide emissions and denitrification N‐loss from European soils?
Authors: Kaiser E.‐A. , Eiland F. , Germon J. C. , Gispert M. A. , Heinemeyer O. , Henault C. , Lind A. M. , Maag M. , Saguer E. , Van Cleemput O. , Vermoesen A. , Webster C.
Published: December 2011

N20 emissions and denitrification N‐losses. precipitation, air temperature, soil moisture, bulk density and content of mineral N were monitored in 9 different agricultural soils in 6 European countries throughout the vegetation period (April to September) 1992 and 1993. N2O emissions and denitrification N‐losses were log‐normal distributed, reflecting high temporal changes.

While small flux rates (< 2 g N ha−1 d−1) were detectable every day, high rates (> 10 g N ha−1 d−1) were measured after fertilization.

An attempt to relate the emission variables to climate and soil variables was made through the use of correlation analysis. The mean N20 emissions from soil were significantly correlated with the soil properties clay, organic C and mineral N content and the amount of applied mineral N fertilizer. The best prediction of the N2O emission rates (r2 = 0.734) was achieved by multiple linear regression using the soil parameter clay and mineral N. Only 50% of the observed variation could be explained by the factors Corg and mineral N, which describe the substrate availability for microbial processes. No successful statistical model was found for the prediction of denitrification N‐losses.
Influence of nitrogen concentration and form in the nutrient solution N20 and N2 emissions from a soilless culture system
Authors: Daum Diemo , Schenk Manfred K.
Published: December 2011

The influence of nitrogen concentration and form in the nutrient solution on the N2O and N2 emissions from a closed rockwool system with cucumber crops was investigated. At optimum, nitrate‐accented nitrogen supply of plants (120 mg N l−1) on average 0.59 kg N per hectare greenhouse area and day was released. Comparable emission rates occurred with moderate sub‐ and supraoptimum nitrogen fertilization. Thus, in this range the N supply was non‐limiting for the gaseous nitrogen losses. Only in the case of severe suboptimum N supply (40 mg N l−1) the N2O N2 emissions were clearly lower, probably as a result of diminished plant growth and therefore reduced root respiration and exudation of organic carbon sources for microorganisms. The proportion of nitrous oxide in the gaseous nitrogen losses increased on average from 5 to 13% with increasing N supply, possibly because of an impaired N2O reduction in denitrification due to high nitrate concentrations.

Short‐term shifting with optimum nitrogen supply from nitrate‐ accented composition to pure nitrate did not affect the gaseous nitrogen emissions, whereas an exclusive ammonium supply resulted in a considerable decrease. The results indicated that the N2O emission and the total nitrogen losses from the soilless culture system were predominantly caused by denitrification.
Schadstoffpotential technogener Substrate in Böden urban‐industrieller Verdichtungsräume
Authors: Meuser Helmut
Published: December 2011

In urban‐industriellen Verdichtungsräumen liegen häufig anthropogene Auftragsböden aus Gemengen natürlicher und technogener Substrate vor. Mit der Beimengung technogener Substrate kann eine Akkumulation von Schadstoffen im Boden verbunden sein. Anhand umfangreicher Untersuchungen im zentralen Ruhrgebiet, ergänzt durch Angaben aus der Literatur, wird dargestellt, mit welchen Schadstoffgehalten (As, Cd, Cr. Cu, Hg, Ni, Pb, Zn, Benzo(a)pyren, Σ PCB) bei den unterschiedlichen technogenen Substraten zu rechnen ist. Die Datenmenge erlaubt, dem Belastungsgrad der einzelnen technogenen Substrate Bewertungsklassen in einer fünfstufigen Skala (sehr gering, gering, mittel, hoch, sehr hoch) zuzuordnen.
Hydraulische Eigenschaften von Basaltsaproliten
Authors: Häfele Stephan , Wiechman Horst
Published: December 2011

In Erosionslagen sind Saprolite häufig in beträchtlichem Maße Wurzelraum. Da bisher kaum Untersuchungen zum Wasserhaushalt und den hydraulischen Eigenschaften vorliegen, wurden Basaltsaprolite und zum Vergleich ein ferratlitisches Bodensediment in Stechzylindern und vor allem in größeren Monolithen untersucht. Bestimmt wurde die Porengrößenverleilung sowie die ungesättigte Leitfähigkeit in Abhängigkeit von der Wasserspannung. Klüftung bedingt eine sehr hohe gesättigte Wasserleitfähigkeit. Im Bereich pF 1.8 nimmt die ungesättigte Wasserleitfähigkeit bereits stark ab. Trotz hoher Porenvolumina und einem beträchtlichen Anteil mäßig fest gebundenen Wassers (pF 2.5–4.2), ist dieses für die Pflanzen, in Abhängigkeit von dem Grad der Durchwurzelung, nur zum Teil verfügbar. Die Durchlässigkeit von Saproliten für Sickerwasser wird leicht unter‐ und der Beitrag zur Wasserversorgung der Vegetation leicht überschätzt.
The dynamics of root production and loss in Betula papyrifera seedlings in response to elevated CO2 and an aluminium pulse
Authors: Li Alison , Berntson Glenn M. , Godbold Douglas L. , Bazzaz Fakhri A.
Published: December 2011

Seedlings of Betula papyrifera were grown in sand/nutrient solution cultures in rhizotrone growth containers under elevated (700 ppm) or ambient (375 ppm) atmospheric CO2 concentrations for approximately 10 weeks. Thirty seven days after the begin of the experiment the plants were exposed to a 10 day pulse of 400 or 1200 μM Al. Elevated atmospheric CO2 increased both root production and loss. Exposure to Al reduced root production and slightly reduced root loss. The reduced root production due to Al was amplified after the pulse had receded, resulting in a significantly lower net and gross root production at the end of the experiment. There were no clear CO2 × Al interactions.
Effects of fallow system and cropping frequency upon quantity and composition of earthworm casts
Authors: Hauser Stefan , Asawalam Damian O.
Published: December 2011

The quantities of earthworm surface casts were monitored in traditional bush fallow regrowth (BFR), Pueraria phaseoloides live mulch (PLM), Leucaena leucocephala alley cropping (LAC) and undisturbed forest. The fallow systems were planted to maize/cassava intercrop either permanently or for one year after three years of fallow i.e. at 100 and 25% cropping frequencies. Earthworm casting activity was lower in fields cropped after clearing three year old fallow than in the respective permanently cropped fallow management system. The reduction in casting was related both to the degree of biomass removed through burning and to re‐establishment of cover crops. Higher exchangeable cation concentration in the soil did not cause increased casting activity.

Concentrations of organic C, total N and exchangeable Ca and Mg in casts were significantly higher than in the 0–15 cm topsoil. Exchangeable Ca and Mg in casts did not significantly differ between treatments, with the exception of significantly higher Mg in casts after three years of P. phaseoloides fallow. Topsoil (0–15 cm) exchangeable Ca and Mg were not correlated with cast exchangeable Ca and Mg, but concentrations of organic C and total N in casts were significantly correlated with organic C and total N in the topsoil. Coefficients of variability of organic C, total N and exchangeable Ca and Mg were about twice as high in the soil than in casts. Significant negative correlations between the cast to soil ratio (cast enrichment factor) of organic C, total N and exchangeable Ca and Mg and the respective concentrations in the soil show that earthworms are increasingly selective in organic carbon and nutrient uptake as these parameters of soil fertility are declining.
The occurrence of terrestrial algae on two beech sites on a Cambisol
Authors: Wöhler Ingo , Klaß Stefan , Derakshani Manigee , Stellmacher Gerold , Winter Jörg‐Ulrich , Reißer Werner
Published: December 2011

The occurrence of terrestrial algae on two beech sites was determined qualitatively and quantitatively in the litter, organic and mineral layer. Both sites are beech stands of different age and the soil type is a Cambisol. On the site with young beech the maximal value determined was 1.0 · 108 algae g−1 dw in the litter layer. With increasing soil depth the number of algae decreased on both sites, and at the young beech stand site no algae were found in the mineral soil. Chlorophyceae were the dominant algae group and at the young beech stand Bacillariophyceae were present.
PAK‐Abnahmen in Bodenproben verschiedener Altlaststandorte bei Aktivierung der autochthonen Mikroflora
Authors: Thiele Sören , Brümmer Gerhard W.
Published: December 2011

Im Rahmen von 74‐ bzw. 168wöchigen Freiland‐Gefäßversuchen wurde die PAK‐Abnahme in zehn verschiedenen Altlastbodenproben unterschiedlicher Belastung untersucht. Bestimmt wurden 15 der 16 PAK nach US EPA (ohne Acenaphthylen). Den Bodenproben wurden in verschiedenen Varianten leicht abbaubare organische Substanzen, Mineraldünger sowie synthetische Tenside und z.T. Kalk zugegeben.

In Abhängigkeit von Art und Menge der Zugaben konnte die biologische Aktivität und damit die (co‐)metabolische Abbauleistung der Bodenmikroorganismen erheblich gesteigert werden. In den unterschiedlichen Bodenproben wurde binnen 74 Wochen eine Abnahme der PAK‐Ausgangsgehalte um 12–90% erzielt. Auch von 74–168 Wochen war zum Teil eine deutliche weitere Abnahme der PAK‐Gehalte festzustellen.

Die Abnahmen der Gehalte an extrahierbaren PAK mit zunehmender Versuchsdauer sind v.a. auf mikrobiellen Ab‐, Um‐ und Einbau zurückzuführen und lassen sich durch zwei gekoppelte Exponentialfunktionen für eine anfänglich schnelle und anschließende langsame PAK‐Abnahme beschreiben. Zwei unterschiedliche Prozesse (I, II) bestimmen demnach die PAK‐Abnahme. In der ersten Versuchswoche betragen die Abnahmeraten für Prozeß I 4.2–88.3 und für Prozeß II 0.06–5.3 mg PAK ṁ kg−1 Boden Woche−1; in der 168. Woche sind sie für Prozeß I nicht mehr bestimmbar und betragen für Prozeß II 0.05–2.3 mg ṁ kg−1 ṁ Woche−1. Höhere PAK Ausgangsgehalte bedingen meist größere relative PAK‐Abnahmen. führen jedoch zu höheren absoluten Restgehalten. Die Persistenz der PAK wird v.a. durch ihre Bioverfügbarkeit bestimmt.

Der PAK‐Abbau wird durch die vorgenommenen Bodenbehandlungen erhöht. Dabei steigert die Zugabe von 30 g ṁ kg−1 (w/w) leicht abbaubarer organischer Substanz (C/N‐Verhältnis < 20) in Kombination mit einer erhöhten Nilraigabe und Tensidzusatz die PAK‐Abnahme am effektivsten. Der abbaufördernde Effekt durch Anhebung des pH einer sehr stark sauren Bodenprobe war bei einem pH‐Wert um 6 maximal.
Cyanides in a soil of a former coking plant site
Authors: Mansfeldt Tim , Gehrt Sandra B. , Friedl Josef
Published: December 2011

Soils of former coking plant sites are frequently contaminated with cyanide, which mainly occurs as the pigment Berlin blue, FeIII4 [FeIICN)6]3, and soluble iron cyanide complexes, Fe(CN)63‐/4−. Berlin blue is only slightly soluble under acidic conditions.

The cyanide mobility in a strongly acid soil (pH about 3) of such a site was studied by assessing the distribution of cyanides in the soil and sediment and by conducting batch experiments at different pH levels.

The soil is based on a disposal layer (0–32 cm) overlying sandy loess (32–145 cm) overlying glaciofluvial sand (145–250 cm) overlying marlstone (250–500 cm). Highest cyanide concentrations were found in the disposal layer (62–2865 mg CN− kg−1), medium concentrations in the sandy loess (16–29 mg CN− kg−1), concentrations of about 100 mg CN− kg−1 in the glaciofluvial sand and lowest concentrations in the marlstone (0.22–0.49 mg CN−1 kg−1). The surfaces of macropores, which occur in the sandy loess and finish in the glaciofluvial sand, are dark‐blue dyed and have much higher cyanide concentrations than the surrounding bulk soil. Thus, the accumulation of cyanides in the sand layer may partly be the result of macropore flow.

Batch experiments show a strong pH dependence of the solubility of cyanide in the soil as well as of Berlin blue which was found by Mössbauer spectroscopy to be the dominating or sole iron cyanide.

The time necessary to transport the cyanides solely as hexacyanoferrate into the undisturbed horizons is estimated to 1000 yr. However, because Berlin blue is known to form colloids, we discuss the possibility of cyanide transport as colloid not requiring dissolution and reprecipitation. We postulate that colloidal Berlin blue transported by macropore flow is responsible for the high mobility of cyanides in this acid soil.
Characterisation of a humus profile under beech forest by using wet‐chemistry and CPMAS 13C NMR‐spectroscopy in consideration of spatial heterogeneity
Authors: Wachendorf Christine
Published: December 2011

Three of ten macromorphologically similar humus profiles of a Dystric Cambisol under a beech forest were randomly chosen and the litter and humus layers were characterized by wet‐chemistry and CPMAS 13C NMR‐spectroscopy. The spatial heterogeneity of the litter and humus layers was high for the bulk density and for the sugar and starch fraction; lowest coefficients of variation were obtained for the chemical shift range of O‐Alkyl‐C. The spatial heterogeneity of the layers did not differ by means of all chemical methods. Changes in the chemical composition at the beginning of humification were high from the fresh fallen litter (Ln‐layer) to the morphologically only slightly altered litter in the L‐layer, whereas the changes in the litter and humus layers from the L to the Ohf‐layer were minor. However, the organic matter of the first mineral horizon was characterized by a decrease in lignin and cellulose. With wet‐chemistry and 13C NMR‐spectroscopy similar results were obtained for polysaccharides whereas results which can be attributed to changes in lignin deduced by the methoxyl content differed from each other.
The influence of surfactants applied by sewage sludge on the behaviour of Atrazine and PAHs in semiarid soils
Authors: Litz Norbert , Müller‐Wegener Ulrich
Published: December 2011

The effect of two surfactants applied via sewage sludge: LAS (linear Alkylbenzenesulfonate) and Nonylphenol as a metabolite of Nonylphenol ethoxylate, on PAHs and Atrazine mobility was investigated under semiarid soil conditions in a Vertisol and a Gypsisol treated with sewage sludge. In both cases the surfactants promoted the leachability of Atrazine only moderately compared to the untreated plot. PAHs were leached from the surface layer (0–20 cm) into 20–50 cm layer during the three month test period. Relatively higher leaching was observed in the sandy Gypsisol. Atrazine was leached only in the clayrich Vertisol where the surfactants were present longer than in the plot with sandy Gypsisol.
The fate of freshly added phosphorus in representative agricultural soils
Authors: Assimakopoulos J. , Bovis C. , Kosmas C. , Nychas A.
Published: December 2011

Surface and subsurface samples from 26 representative agricultural soils (13 Entisols, 9 Alfisols and 4 Vertisols) from Central and South Western Greece were equilibrated for a week with P solutions ranging from zero to 800 mg P kg−1 soil. The Freundlich and in the cases of high fine carbonate content (> 6%) the linear equations described the sorption isotherms in a satisfactory way.

Sequential fractionation indicated that a 0.1 M NaOH plus 1 M NaCl + 0.3 M Na‐citrate + 1 M NaHCO3 (buffer) solution extracted more than 60% of the P retained by Entisols containing low to medium fine carbonates and by Vertisols, and less than 60% by Entisols with a high fine carbonate content. In all Entisols, this percentage decreased significantly at P additions higher than 150 mg kg−1. The opposite was observed in Vertisols, in which this fraction was the most important part of the retained P up to the maximum P addition. In contrast, in Alfisols this fraction reached 100%, but in the case of high Bray‐P (> 50 ppm) it was more than 100% of the retained P. The second fraction extracted with the 0.3 M Na‐citrate + 1 M NaHCO3 buffer plus Na‐dithionite was found to be much smaller than the first fraction, increasing with P additions in absolute amounts but remaining constant as a percentage of the retained P, ranging from 15–35% among the studied samples. The third fraction obtained with 1 M HCl solution showed a peculiar behaviour. It was close to zero of the retained P in samples containing carbonates (Entisols and Vertisols) at P additions up to 300 mg kg−1 soil, but increased significantly at higher P additions and almost doubled in Entisols. Finally, the P fraction obtained after seven successive extractions with 0.01 M CaCl2, correlated well by a polynomial of 2nd degree equation with NaOH+CB‐P and linearly with Olsen‐P and Bray‐P.
Measuring interlayer potassium release rates from soil materials. II. A percolation procedure to study the influence of the variable ‘solute K’ in the < 1…10 μM range
Authors: Springob Günther , Richter Jörg
Published: December 2011

Release rates of nonexchangeable K from Ap material of a Luvisol (‘Eckerde’ loess, 15% clay) are determined using a percolation procedure which avoids the common artifacts due to shaking or stirring soil suspensions and thus provides less biased kinetic data. CaCl2 solution (10 mMc. 20 °C. pH 5.8) is percolated through packages of soil aggregates (0.5–1 mm grain size, 0.5 g samples) with 0.02 to 25 ml h−1. Solute K (CK) was varied between < 1 and > 10 μM and is shown to have a dominant influence on the rates of interlayer K release. These increase exponentially below 3.5 μM (no steady state but steady decrease of release rates in each sample). The difference between the related CK between moderate and high release rates is as small as 1 μM K. The average rates, of a 10‐day‐interval, starting after 1.3 times the exchangeable K had been removed, are 40 μmol K kg−1 soil d−1 at 4 μM CK and 240 μmol kg−1 d−1 at 3 μM CK, respectively. It is concluded that larger quantities of interlayer K become plant available in the studied soil if the of soil solutions gets below 3.5 μM (for 10 mMc Ca, 20 °C, pH 5.8), probably because the dominant dioctahedral illites start to join the release process below this critical limit. The higher K concentration range was accounted for by K‐Ca exchange isotherms which, by alteration of shape, indicate that Knex release becomes measurable below 10 to 20 μM K. It is further argued that existing diffusion or reaction kinetics approaches towards K release are incomplete because the influence of solute K is not considered.
The regulation of apoplastic calcium in relation to intracellular signalling in stomatal guard cells
Authors: Lionel D. , De Silva R. , Hetherington Alistair M. , Mansfield Terry A.
Published: December 2011

It is now well established that calcium has a substantive role in intracellular signalling in stomatal guard cells. Much less attention has, however, been paid to the importance of maintaining an apoplastic calcium concentration which permits this mechanism to operate. Data are presented for the calcicole Leontodon hispidus, in which the xylem sap may contain over 16 mM free calcium, showing that the concentration of calcium in the guard cell apoplast may be as low as 0.10 mM. This appears to be achieved by the deposition of considerable amounts of calcium oxalate in the mesophyll, particularly in the palisade tissue. Of the calcium delivered directly into the epidermis by the transpiration stream, a large proportion is diverted into the trichomes.

It seems unlikely that stomatal regulation over long distances (e.g. from root to shoot) is accomplished via apoplastic calcium, but over shorter distances (the span of a few cells in the epidermis) signalling via calcium in the apoplast is entirely feasible and it is worthy of further investigation.
Parameterization and regionalization of Cd sorption characteristics of sandy soils. I. Freundlich type parameters
Authors: Springob Günther , Böttcher Jürgen
Published: December 2011

Cd sorption isotherms (n = 24) were established for arable, sandy soils of the ‘Fuhrberger Feld’ catchment area northeast of Hannover (Germany) using 0.01 Mc Ca(NO3)2 solution with Cd additions ranging from 0 to 44 μMc Cd. Alternative fractions of initially (prior to analysis) sorbed Cd (S0) were added to the amount sorbed during the experiments. The Freundlich equation was fitted to the resulting isotherms. The obtained retention parameters k and M varied with respect to the different S0 fractions. Isotherms corrected with CdEDTA as S0 fraction were nonlinear in their log‐form. The highest degree of log‐linearity is obtained if S0 is characterized by 40% of the agua regia extractable Cd. The corresponding k values ranged from 36 to 1275 g1‐M LM kg−1 (mean 338 g1‐M LM kg−1, cv = 92%). The Freundlich exponent M showed less variation (0.7 to 1.1, cv = 12%) with a mean of 0.88. Functions based on these parameters predicted Cd concentrations in Ca(NO3)2−soil suspensions well (r2 = 0.96) but were hardly related to Cd concentrations of ‘fresh’ soil solutions (r2 = 0.20).
Quasi‐convexly dense and suitable sets in the arc component of a compact group
Authors: Dikranjan Dikran , Shakhmatov Dmitri
Published: December 2011

Let G be an abelian topological group. The symbol \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\widehat{G}$\end{document} denotes the group of all continuous characters \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\chi :G\rightarrow {\mathbb T}$\end{document} endowed with the compact open topology. A subset E of G is said to be qc‐dense in G provided that χ(E)⊆φ([− 1/4, 1/4]) holds only for the trivial character \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\chi \in \widehat{G}$\end{document}, where \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\varphi : {\mathbb R}\rightarrow {\mathbb T}={\mathbb R}/{\mathbb Z}$\end{document} is the canonical homomorphism. A super‐sequence is a non‐empty compact Hausdorff space S with at most one non‐isolated point (to which S converges). We prove that an infinite compact abelian group G is connected if and only if its arc component Ga contains a super‐sequence converging to 0 that is qc‐dense in G. This gives as a corollary a recent theorem of Außenhofer: For a connected locally compact abelian group G, the restriction homomorphism \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$r:\widehat{G}\rightarrow \widehat{G}_a$\end{document} defined by \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$r(\chi )=\chi \upharpoonright _{G_a}$\end{document} for \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\chi \in \widehat{G}$\end{document}, is a topological isomorphism. We show that an infinite compact group G is connected if and only if its arc component Ga contains a super‐sequence converging to the identity that is qc‐dense in G and generates a dense subgroup of G. We also offer a short alternative proof of the result of Hofmann and Morris on the existence of suitable sets of minimal size in the arc component of a compact connected group.
On the gradient flow for the anisotropic area functional
Authors: Pozzi Paola
Published: December 2011

We consider the anisotropic mean curvature flow for parametrized hypersurfaces and provide a new definition of gradient flow that takes into account the anisotropic nature of space. With this new approach we succeed in identifying the natural candidate for the anisotropic mean curvature vector using a variational method. Under the obtained flow Wulff shapes shrink self similarly. The new definition of gradient flow relies on understanding which Banach structure plays a fundamental role and performing a consistent choice of function spaces. The geometric setting we introduce also allows us to provide and justify a natural formulation for the anisotropic Willmore functional. Its first variation is computed.
Partner Characteristics, Information Asymmetry, and the Signaling Effects of Joint Ventures
Authors: Kumar Shyam , Park Jong Chool
Published: December 2011

We provide theory and evidence regarding the signaling effects of joint venture (JV) announcements. We argue that when a firm characterized by information asymmetry with respect to the stock market announces a JV, the growth opportunities and the quality of resources of the partner provides a signal to investors about the true value of the firm. Our study shows that (i) apart from synergies, JV announcements impact firm value also because of the information they convey about future growth opportunities; and (ii) JVs may not only validate but also ‘invalidate’ the quality of a firm by revealing that it is unable to attract strong partners. Copyright © 2011 John Wiley & Sons, Ltd.
Enhanced meta‐analysis of acetylcholine binding protein structures reveals conformational signatures of agonism in nicotinic receptors
Authors: Stober Spencer T. , Abrams Cameron F.
Published: December 2011

The soluble acetylcholine binding protein (AChBP) is the default structural proxy for pentameric ligand‐gated ion channels (LGICs). Unfortunately, it is difficult to recognize conformational signatures of LGIC agonism and antagonism within the large set of AChBP crystal structures in both apo and ligand‐bound states, primarily because AChBP conformations in this set are nearly superimposable (root mean square deviation < 1.5 Å). We have undertaken a systematic, alignment‐free approach to elucidate conformational differences displayed by AChBP that cleanly differentiate apo/antagonist‐bound from agonist‐bound states. Our approach uses statistical inference based on both crystallographic states and conformations sampled during long molecular dynamics simulations to select important inter‐Cα distances and map their collective values onto functional states. We observe that binding of (nAChR) agonists to AChBP elicits clockwise rotation of the inner β‐sheet with respect to the outer β‐sheet, causing tilting of the cys‐loop away from the five‐fold axis, in a manner quite similar to that speculated for α‐subunits of the heteromeric nAChR structure (Unwin, J Mol Biol 2005;346:967), making this motion potentially important in transmission of the gating signal to the transmembrane domain of a LGIC. The method is also successful at discriminating partial from full agonists and supports the hypothesis that a particularly controversial ligand, lobeline, is in fact an LGIC antagonist.
Evaluation of deep levels in In0.53Ga0.47As and GaAs0.5Sb0.5 using low‐frequency noise and RTS noise characterization
Authors: Chen Wenjie , Yuan Jinrong , Holmes Archie , Fay Patrick
Published: December 2011

Quantum‐well photodetectors based on lattice‐matched InGaAs/GaAsSb heterostructures on InP are promising candidates for mid‐infrared detection. However, the dark current in these devices can be elevated by the presence of deep levels. In this work, both bulk and interfacial deep levels in MBE‐grown homojunctions and heterojunctions are studied experimentally using low‐frequency noise spectroscopy and random telegraph signal (RTS) characterization. Several bulk and interface‐related levels have been identified and characterized in terms of energy level, cross‐section and trap type. It is expected that these ongoing defect studies will enable the growth of the higher‐quality material and heterostructures needed for future‐generation mid‐IR detectors and devices. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ferromagnetic and transport properties of p‐type (Zn,Mn,Sn)As2thin films grown on InP substrates for various Mn contents
Authors: Uchitomi N. , Endoh H. , Oomae H. , Yamazaki M. , Toyota H. , Jinbo Y.
Published: December 2011

(Zn,Mn,Sn)As2 thin films containing Mn at more than 10% of cation sites were grown on InP substrates by molecular beam epitaxy (MBE). These films showed p ‐type conductivity and ferromagnetism with a Curie temperature greater than 330 K. They also indicated ferromagnetism, regardless of whether they are semiconducting or metallic. We discovered a linear relationship between the Curie temperature and Mn content in (Zn,Mn,Sn)As2 thin films. The experimental results are expected to provide an important clue to understanding the origin of ferromagnetism in ferromagnetic chalcopyrites, suggesting that the ferromagnetism in these materials derives from the scheme of hole‐mediated ferromagnetic interaction. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characteristics of PHEMTs and MSM photodetectors simultaneously fabricated on same epitaxial wafer with In0.75Ga0.25As/InGaAs channel layer
Authors: Koreeda Yuta , Endo Yutaka , Sato Kouichi , Yoshizawa Kenya , Nishio Yui , Taguchi Hirohisa , Iida Tsutomu , Takanashi Yoshifumi
Published: December 2011

InP‐based high electron mobility transistors with a pseudomorphically strained InAs channel (InAs‐PHEMTs) have been receiving much attention because of their excellent high‐frequency performance. Metal‐semiconductor‐metal photodetectors (MSM‐PDs) are very attractive as high speed optical receivers because they can be monolithically integrated with InAs‐PHEMTs on the same epitaxial wafer for developing high‐speed optoelectronic integrated circuits.

In this study, InAs‐PHEMTs and PMSM‐PDs were fabricated simultaneously on the same epitaxial wafer with a channel layer composed of strained In0.75Ga0.25As/In0.53Ga0.47As. We demonstrated a current cut‐off frequency as high as 151 GHz for PHEMTs with a gate length of 0.1 μm and an optical response time as low as 18 ps for the PMSM‐PDs with a line and space width of 0.2 and 0.6 μm, respectively (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)