Böden in der Dauerbeobachtung: Räumliche und zeitliche Veränderung von organischem Kohlenstoff und Gesamtstickstoff im Oberboden auf fünf unterschiedlich genutzten Ackerstandorten im Biosphärenreservat Schorfheide-Chorin

Die Biosphärenreservate sind durch die Vorgaben des MAB-Programms dazu angehalten eine ökosystemar ausgerichtete Umweltbeobachtung zu installieren. Im Rahmen der „Ökosystemaren Umweltbeobachtungen in den Biosphärenreservaten Brandenburgs“(ÖUB) werden seit 1999 regelmäßig fünf Ackerstandorte im Biophärenreservat Schorfheide-Chorin (BR SC) untersucht. Der Boden stellt dabei, neben der Flora und Fauna, einen wichtigen Untersuchungskomplex dar. Ziel der Beobachtung ist es Veränderungen der Bodenfunktionen (Veränderungen der Humusgehalte, Trophie) auf unterschiedlichen Standorttypen und unter differierender Bewirtschaftung (konventionell und Ökolandbau) aufzuzeigen. Aus diesem Grund sind jeweils zwei „Standortpaare“ mit ähnlicher Bodenformenausstattung (Pararendzina-Parabraunerden-Kolluvisol auf D5b2-07-Standort bzw. Parabraunerde-Kolluvisol auf D5a1-09-Standort), aber unterschiedlicher Bewirtschaftungsform ausgewählt worden. Alle diese Dauerbeobachtungsflächen weisen ein mittel bis stark welliges Relief mit eingestreuten Söllen auf. Der fünfte Standort ist ein Acker mit durchgängig sandigem Substrat (D1a1-01-Standort), der zu DDR-Zeiten als Güllehochlastfläche diente. Um die in sich sehr heterogenen Standorte hinsichtlich ihrer strukturellen und chemischen Bodenentwicklung charakterisieren zu können, wurden jeweils Hangcatenen zur Beprobung angelegt und in einem 3 bzw. 6-jährigen Turnus untersucht. Im Beitrag werden Ergebnisse der 18-jährigen Untersuchungsreihen der fünf Hangcatenen präsentiert. Der Fokus wird auf die Beschreibung und Interpretation von zeitlichen Veränderungen des organischen Kohlenstoffs und des Gesamtstickstoffs entlang der Hangcatenen gelegt einschließlich der räumlichen Differenzierungen. Die aufgezeigten Entwicklungen werden den erhobenen Daten zur Nutzung und Witterungsdaten gegenübergestellt und analysiert, welchen Einfluss die verschiedenen Bewirtschaftungsformen bzw. die Witterung auf beide Parameter ausüben. Außerdem wird analysiert, ob sich innerhalb des Untersuchungszeitraumes Unterschiede im räumlichen Muster entlang der Catena ergeben haben

The Randomized Shortened Dental Arch Study: Tooth Loss

The evidence concerning the management of shortened dental arch (SDA) cases is sparse. This multi-center study was aimed at generating data on outcomes and survival rates for two common treatments, removable dental prostheses (RDP) for molar replacement or no replacement (SDA). The hypothesis was that the treatments lead to different incidences of tooth loss. We included 215 patients with complete molar loss in one jaw. Molars were either replaced by RDP or not replaced, according to the SDA concept. First tooth loss after treatment was the primary outcome measure. This event occurred in 13 patients in the RDP group and nine patients in the SDA group. The respective Kaplan-Meier survival rates at 38 months were 0.83 (95% CI: 0.74-0.91) in the RDP group and 0.86 (95% CI: 0.78-0.95) in the SDA group, the difference being non-significant

Survival Rate, Fracture Strength and Failure Mode of Ceramic Implant Abutments After Chewing Simulation

The aim of this study was to compare titanium-reinforced ZrO2 and pure Al2O3 abutments regarding their outcome after chewing simulation and static loading. Forty-eight standard diameter implants with an external hexagon were divided into three groups of 16 implants each and restored with three different types of abutments (group A: ZrO2 abutments with titanium inserts; group B: densely sintered high-purity Al2O3 abutments; group C: titanium abutments). All abutments were fixated on the implants with gold-alloy screws at 32 Ncm torque, and metal crowns were adhesively cemented onto the abutments. The specimens were exposed to 1.2 million cycles in a chewing simulator. Surviving specimens were subsequently loaded until fracture in a static testing device. Fracture loads (N) and fracture modes were recorded. A Wilcoxon Rank test to compare fracture loads among the 3 groups and a Fisher exact test to detect group differences in fracture modes were used for statistical evaluation (

Trueness of CAD/CAM digitization with a desktop scanner – an in vitro study

Desktop scanners are devices for digitization of conventional impressions or gypsum casts by indirect Computer-Aided Design/Computer-Assisted Manufacturing (CAD/CAM) in dentistry. The purpose of this in vitro study was: 1, to investigate whether virtual models produced by the extraoral scanner have the same trueness as sectioned casts; and 2, to assess if digitization with an extraoral scanner influences the surface information

Role of P2 purinergic receptors in synaptic transmission under normoxic and ischaemic conditions in the CA1 region of rat hippocampal slices

The role of ATP and its stable analogue ATPγS [adenosine-5′-o-(3-thio)triphosphate] was studied in rat hippocampal neurotransmission under normoxic conditions and during oxygen and glucose deprivation (OGD). Field excitatory postsynaptic potentials (fEPSPs) from the dendritic layer or population spikes (PSs) from the soma were extracellularly recorded in the CA1 area of the rat hippocampus. Exogenous application of ATP or ATPγS reduced fEPSP and PS amplitudes. In both cases the inhibitory effect was blocked by the selective A1 adenosine receptor antagonist DPCPX (8-cyclopentyl-1,3-dipropylxanthine) and was potentiated by different ecto-ATPase inhibitors: ARL 67156 (6-N,N-diethyl-D-β,γ-dibromomethylene), BGO 136 (1-hydroxynaphthalene-3,6-disulfonate) and PV4 [hexapotassium dihydrogen monotitanoundecatungstocobaltate(II) tridecahydrate, K6H2[TiW11CoO40]·13H2O]. ATPγS-mediated inhibition was reduced by the P2 antagonist suramin [8-(3-benzamido-4-methylbenzamido)naphthalene-1,3,5-trisulfonate] at the somatic level and by other P2 blockers, PPADS (pyridoxalphosphate-6-azophenyl-2′,4′-disulfonate) and MRS 2179 (2′-deoxy-N6-methyladenosine 3′,5′-bisphosphate), at the dendritic level. After removal of both P2 agonists, a persistent increase in evoked synaptic responses was recorded both at the dendritic and somatic levels. This effect was prevented in the presence of different P2 antagonists. A 7-min OGD induced tissue anoxic depolarization and was invariably followed by irreversible loss of fEPSP. PPADS, suramin, MRS2179 or BBG (brilliant blue G) significantly prevented the irreversible failure of neurotransmission induced by 7-min OGD. Furthermore, in the presence of these P2 antagonists, the development of anoxic depolarization was blocked or significantly delayed. Our results indicate that P2 receptors modulate CA1 synaptic transmission under normoxic conditions by eliciting both inhibitory and excitatory effects. In the same brain region, P2 receptor stimulation plays a deleterious role during a severe OGD insult

The role of ATP and adenosine in the brain under normoxic and ischemic conditions

By taking advantage of some recently synthesized compounds that are able to block ecto-ATPase activity, we demonstrated that adenosine triphosphate (ATP) in the hippocampus exerts an inhibitory action independent of its degradation to adenosine. In addition, tonic activation of P2 receptors contributes to the normally recorded excitatory neurotransmission. The role of P2 receptors becomes critical during ischemia when extracellular ATP concentrations increase. Under such conditions, P2 antagonism is protective. Although ATP exerts a detrimental role under ischemia, it also exerts a trophic role in terms of cell division and differentiation. We recently reported that ATP is spontaneously released from human mesenchymal stem cells (hMSCs) in culture. Moreover, it decreases hMSC proliferation rate at early stages of culture. Increased hMSC differentiation could account for an ATP-induced decrease in cell proliferation. ATP as a homeostatic regulator might exert a different effect on cell trophism according to the rate of its efflux and receptor expression during the cell life cycle. During ischemia, adenosine formed by intracellular ATP escapes from cells through the equilibrative transporter. The protective role of adenosine A1 receptors during ischemia is well accepted. However, the use of selective A1 agonists is hampered by unwanted peripheral effects, thus attention has been focused on A2A and A3 receptors. The protective effects of A2A antagonists in brain ischemia may be largely due to reduced glutamate outflow from neurones and glial cells. Reduced activation of p38 mitogen-activated protein kinases that are involved in neuronal death through transcriptional mechanisms may also contribute to protection by A2A antagonism. Evidence that A3 receptor antagonism may be protective after ischemia is also reported

Zur Diasporen-Keimfähigkeit von Segetalpflanzen: Untersuchungen in Nord-Thüringen

Das plötzliche Wiederauftreten von Ackerwildkrautarten nach spontanen Umbrüchen ehemals beackerter und dann anderweitig genutzter oder brachgefallener Flächen regte zu einer vertiefenden Betrachtung der Lebensdauer von Diasporen dieser Pflanzen an. Im Rahmen einer Diplomarbeit an der FH Eberswalde wurde neben einer intensiven Literaturrecherche ein Feldversuch zur Prüfung der Keimfähigkeit unter natürlichen Bedingungen ausgewertet. Auf ehemaligen Ackerflächen im südlichen Kyffhäusergebirge wurde durch Umbrechen des Bodens eine Initialmaßnahme zur Aktivierung der Diasporen-bank ergriffen. Die im Versuch erzielten Ergebnisse wurden mit den Ergebnissen der Literaturrecherche verglichen und bewertet. Es ist festzustellen, daß stark abweichende Angaben zur Langlebigkeit einiger Arten vorliegen. Dies erklärt sich daraus, daß die ermittelten Werte offenbar vor allem von den konkreten Versuchbedingungen und von den verschiedenen Lagerungsbedingugen abhängen. Mit allen Vorbehalten kann man feststellen, daß ca. 50% der Ackerwildkräuter Thüringens eine Überlebensfähigkeit ihrer Verbreitungseinheiten von mehr als 20 Jahren besitzen! Nur neun Arten besitzen eine vorübergehende (transiente) Diasporenbank und können weniger als ein Jahr überdauern. So ist festzustellen, daß gerade in häufig gestörten Lebensräumen viele Arten zu finden sind, deren Populationen oft über sehr dauerhafte Diasporen verfügen. Diasporenbanken spielen für populations- und vegetationsdynamische Prozesse, vor allem nach Störungen der Ökosysteme eine große Rolle. Sie sollten stärker bei Belangen des Arten- und Biotopschutz wie auch in den "Roten Listen" Berücksichtigung finden. Dies gilt vor allem bei Extensivierungsmaßnahmen intensiv genutzter Standorte. Germination capacity of weed seeds - investigations in the north of Thuringia. The subject of this article is the survival of buried weed in former arable lands after tilling inspired us to investigate the longevity of their seeds. In the context of a dissertation at the University of Applied Sciences Eberswalde we analyzed the germination capacity under field conditions in addition to an intensive literature research. To mobilize the diaspore bank fallow land in the south of the Kyffhäuser-Mountains had been ploughed. The results of the field tests had been compared with the results of the literature research. Data about the longevities of weend seeds are exceptionally variable in the literature. The main sources of this variability are the different test and storage conditions. With all reserves we could ascertain that more than 50% of the seeds of weed plants in Thuringia can germinate after more than 20 years in the soil. Only nine species form a transient diaspore bank and survive less than one year, i. e., that particularly in frequently disturbed habitats, as for instant agricultural crop land, a lot of species will be found, which dispose of a diaspore bank with a high persistance. Especially after disturbances of ecosystems diaspore banks have a great influence on the dynamics of populations and communities. Teh diaspore banks should be considered more in conservation programmes and the Red Lists. This applies especially to extensificaition of arable lands with intensive land use

Entwicklung und Aufbau eines Landschaftsmonitoring-Programms im Biosphaerenreservat Schorfheide-Chorin Endbericht

SIGLEAvailable from TIB Hannover: F01B1234 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); Arbeitsgemeinschaft Industrieller Forschungsvereinigungen 'Otto von Guericke' e.V. (AIF), Koeln (Germany)DEGerman

In-vivo serotonin transporter availability and somatization in healthy subjects

Dysregulation of the central serotonergic system is implicated in somatization, which can lead to manifest mental disease. However, neuroimaging studies on serotonin transporter (SERT) availability and somatoform symptoms as assessed by the Symptom Checklist 90 Revised (SCL-90-R) are sparse and reveal inconsistent results. The aim of this study was to explore for the first time the relationship between SERT and somatoform symptom expression in healthy volunteers including the analysis of the SERT-LPR genotype. Fourteen healthy subjects (age 36.07 ± 7.22 years, 9 females) completed the SCL-90-R, underwent [11C]DASB PET and were genotyped on the same day. SERT binding potentials (BPND) were quantified with the multilinear reference tissue model (MRI coregistration). The BPND of the right orbitofrontal cortex (OFC) correlated positively with the somatization subscale. The SERT availability of the right OFC correlated significantly with the obsessive–compulsive subscale and the degree of anxiety was associated with the BPND of the right hippocampus. No main genotype effect on regional SERT availability or on the association between SERT BPND and the respective SCL-90-R subscales was observed. Our findings document a positive correlation between frontal SERT availability and the severity of somatoform symptoms prior to the onset of disease