Serotonin, Motivation, and Playfulness in the Juvenile Rat

The effects of the selective 5HT1A agonist 8-OH-DPAT were assessed on the play behavior of juvenile rats. When both rats of the test pair were comparably motivated to play, the only significant effect of 8-OH-DPAT was for play to be reduced at higher doses. When there was a baseline asymmetry in playful solicitation due to a differential motivation to play and only one rat of the pair was treated, low doses of 8-OH-DPAT resulted in a collapse of asymmetry in playful solicitations. It did not matter whether the rat that was treated initially accounted for more nape contacts or fewer nape contacts, the net effect of 8-OH-DPAT in this model was for low doses of 8-OH-DPAT to decrease a pre-established asymmetry in play solicitation. It is concluded that selective stimulation of 5HT1A receptors changes the dynamic of a playful interaction between two participants that are differentially motivated to play. These results are discussed within a broader framework of serotonergic involvement in mammalian playfulness

Microfluidic PLGA Microcapsules for the Sustained Delivery of Recombinant Human Bone Morphogenetic Protein 2 in 3D Printed PCL/βTCP Scaffolds

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a clinically available osteoinductive growth factor. In its current form, approved for clinical use, however, the growth factor is delivered in excessively high doses, resulting in unpredictable bone growth and unwanted, sometimes life-threatening, clinical side effects. It has clearly been demonstrated that the sustained, long-term release of the proteins can lead to improved ossification, owing particularly to the rapid metabolism of the biologically active growth factor when delivered alone in solution. Delivery systems for rhBMP-2 have been investigated extensively; yet still, further exploration into the best means of protein delivery — in order to curb the side effect profile and improve the quality of the bone generated — is warranted. The present review of literature introduces extensive work evaluating optimal rhBMP-2 delivery, with particular focus on natural polymers, inorganic materials, as well as synthetic materials. In particular, poly(DL-lactide-co-glycolide) (PLGA) microspheres, conventionally fabricated by a solvent extraction/evaporation procedure, are discussed for their use in sustained drug delivery. The application of rhBMP-2 for bone tissue engineering holds great promise for researchers and clinicians in both the medical and dental fields; yet, there remains a need for further investigation into improved protein delivery mechanisms

Do Wages Rise when Corporate Taxes Fall? - Evidence from Germany's Tax Reform 2000

We contribute to the empirical literature on the effective incidence of corporate income taxation by using the German Business Tax Reform of the year 2000 (GBTR 2000) as a natural experiment. Its effect on wages in the manufacturing sector is identified by means of a difference-in-differences analysis that uses French firms as comparison group. We provide evidence that GBTR 2000 led to a significant and sizeable wage effect. For 2001, the first year after GBTR 2000 took effect, we estimate a short-run effect that implies a wage increase of 7.9 percent. Due to the dynamic nature of the empirical model used, the incidence effect grows gradually over time during the evaluation period.Der Zusammenhang zwischen Unternehmensbesteuerung und Lohnentwicklung ist ein theoretisch wie empirisch kontrovers diskutiertes Thema. Umstritten ist insbesondere, in welchem Umfang und unter welchen Bedingungen die durch die Körperschaftsteuer oder andere Formen der Gewinnbesteuerung de jure im Unternehmen entstehende Steuerlast de facto auf den Faktor Lohn überwälzt wird. Zu dieser Frage der so genannten effektiven Inzidenz der Körperschaftsteuer leistet das Paper einen empirischen Beitrag. Dazu wird die deutsche Unternehmenssteuerreform des Jahres 2000 als natürliches Experiment interpretiert. Mithilfe eines Differenz-von-Differenzen-Ansatzes werden die Auswirkungen der Reform auf die Löhne im Verarbeitenden Gewerbe identifiziert. Unternehmen aus Frankreich werden dabei als Vergleichsgruppe herangezogen. Wir finden Evidenz dafür, dass die Reform zu einem signifikanten und beträchtlichen Lohnzuwachs geführt hat. Für das Jahr 2001, dem ersten Jahr nach Inkrafttreten der Reform, wird ein kurzfristiger Effekt in Höhe eines Lohnzuwachses von 7,9 Prozent geschätzt. Entsprechend der dynamischen Spezifikation des ökonometrischen Modells steigt der Inzidenzeffekt der Reform innerhalb der Evaluationsperiode graduell an

Einkommensteuer senken, Pendlerpauschale abschaffen!

Wenn das Bundesverfassungsgericht (BVG) am 9. Dezember 2008 sein Urteil darüber verkündet, ob die geltende gesetzliche Regelung zur Pendlerpauschale verfassungswidrig ist, dann steht ihre juristische Bewertung im Vordergrund. Aktuell werden die Aufwendungen der nicht-selbständigen Arbeitnehmer und der Selbständigen für Wege zwischen Wohnung und Arbeitsstätte vom Gesetzgeber zwar nicht mehr als Werbungskosten anerkannt, im Rahmen einer Härtefallregelung wird Berufspendlern jedoch übergangsweise ab dem 21. Kilometer eine Entfernungspauschale von 0,30 Euro/km gewährt. Die Entscheidung des BVG erfolgt zu einer Zeit, in der sich in der politischen Debatte eine Meinungsmehrheit für eine Rückkehr zur ursprünglichen Regelung - Entfernungspauschale ab dem ersten Kilometer - abzeichnet. Stellt man allerdings die Frage nach der ökonomischen Rechtfertigung für den Steuerabzug von berufsbedingten Fahrtkosten, so können weder die Beibehaltung der aktuellen noch eine Rückkehr zur alten Regelung überzeugen. Nach unserer Auffassung unterstützt das Kriterium der ökonomischen Effizienz bei allen verbleibenden Widersprüchen pro und contra die Möglichkeit zur Anrechnung einer Entfernungspauschale nicht. Unsere empirische Analyse der Verteilungswirkungen zeigt darüber hinaus, dass aufgrund der Möglichkeit, einen Arbeitnehmer-Pauschbetrag von 920 Euro pro Jahr steuermindernd geltend zu machen, die Entfernungspauschale in der Praxis eine vergleichsweise bescheidene Relevanz aufweist. Zudem kommt sie in höherem Maße den Steuerpflichtigen mit höherem Einkommen zu Gute, weshalb es schwer fallen dürfte, sie aus Gründen der Gerechtigkeit zu verteidigen. Die Empfehlung des RWI Essen lautet daher, die Pendlerpauschale aus dem Steuerrecht zu streichen und gleichzeitig die Einkommensteuer zu senken, um eine Mehrbelastung der Steuerpflichtigen zu vermeiden. In dieser RWI : Position erläutern wir zunächst den Hintergrund der aktuellen Debatte (Abschnitt 1), diskutieren daran anschließend, ob eine Pendlerpauschale den Maßstab der ökonomischen Effizienz erfüllt (Abschnitt 2), und überprüfen darauf aufbauend durch empirische Analysen die Verteilungswirkungen unterschiedlicher Regelungen zur Pendlerpauschale (Abschnitt 3). Unser abschließendes Fazit verdichtet die Ergebnisse zu der wirtschaftspolitischen Empfehlung, die Pendlerpauschale bei gleichzeitiger Senkung der Einkommensteuer abzuschaffen

The opacity of grains in protoplanetary atmospheres

We have computed the size distribution of silicate grains in the outer radiative region of the envelope of a protoplanet evolving according to the scenario of Pollack et al. (1996). Our computation includes grain growth due to Brownian motion and overtake of smaller grains by larger ones. We also include the input of new grains due to the breakup of planetesimals in the atmosphere. We follow the procedure of Podolak (2003), but have speeded it up significantly. This allows us to test the sensitivity of the code to various parameters. We have also made a more careful estimate of the resulting grain opacity. We find that the grain opacity is of the order of $10^{-2}\ \mathrm{cm^2 g^{-1}}$throughout most of the outer radiative zone as Hubickyj et al. (2005) assumed for their low opacity case, but near the outer edge of the envelope, the opacity can increase to$\sim{1} \mathrm{cm^2 g^{-1}}$. We discuss the effect of this on the evolution of the models.Comment: 28 pages, 13 Figs., to be published in Icarus (accepted Sep. 2007

The progress of early phase bone healing using porous granules produced from calcium phosphate cement

<p>Abstract</p> <p>Objective</p> <p>Bone grafting is a vital component in many surgical procedures to facilitate the repair of bone defects or fusions. Autologous bone has been the gold standard to date in spite of associated donor-site morbidity and the limited amount of available donor bone. The aim of this study was to investigate the progress of bone regeneration and material degradation of calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder compared to the use of autologous bone grafting in the treatment of "critical size defects" on load-bearing long bones of minipigs.</p> <p>Methods</p> <p>A critical size defect in the tibial metaphysis of 16 mini-pigs was filled either with autologous cancellous graft or with micro- and macroporous carbonated, apatic calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder. After 6 weeks, the specimens were assessed by X-ray and histological evaluation. The amount of new bone formation was analysed histomorphometrically.</p> <p>Results</p> <p>The semi-quantitative analysis of the radiological results showed a complete osseous bridging of the defect in three cases for the autograft group. In the same group five animals showed a beginning, but still incomplete bridging of the defect, whereas in the CPG group just two animals developed this. All other animals of the CPG group showed only a still discontinuous new bone formation. Altogether, radiologically a better osseous bridging was observed in the autograft group compared to the CPG group.</p> <p>Histomorphometrical analysis after six weeks of healing revealed that the area of new bone was significantly greater in the autograft group concerning the central area of the defect zone (p < 0.001) as well as the cortical defect zone (p < 0.002). All defects showed new bone formation, but only in the autograft group defects regenerated entirely</p> <p>Conclusions</p> <p>Within the limits of the present study it could be demonstrated that autologous cancellous grafts lead to a significantly better bone regeneration compared to the application of calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder after 6 weeks. In the early phase of bone-healing, the sole application of CPG appears to be inferior to the autologous cancellous grafts in an <it>in vivo </it>critical size defect on load-bearing long bones of mini-pigs.</p

Sulfur cycling in an iron oxide-dominated, dynamic marine depositional system: The Argentine continental margin

The interplay between sediment deposition patterns, organic matter type and the quantity and quality of reactive mineral phases determines the accumulation, speciation, and isotope composition of pore water and solid phase sulfur constituents in marine sediments. Here, we present the sulfur geochemistry of siliciclastic sediments from two sites along the Argentine continental slope—a system characterized by dynamic deposition and reworking, which result in non-steady state conditions. The two investigated sites have different depositional histories but have in common that reactive iron phases are abundant and that organic matter is refractory—conditions that result in low organoclastic sulfate reduction rates (SRR). Deposition of reworked, isotopically light pyrite and sulfurized organic matter appear to be important contributors to the sulfur inventory, with only minor addition of pyrite from organoclastic sulfate reduction above the sulfate-methane transition (SMT). Pore-water sulfide is limited to a narrow zone at the SMT. The core of that zone is dominated by pyrite accumulation. Iron monosulfide and elemental sulfur accumulate above and below this zone. Iron monosulfide precipitation is driven by the reaction of low amounts of hydrogen sulfide with ferrous iron and is in competition with the oxidation of sulfide by iron (oxyhydr)oxides to form elemental sulfur. The intervals marked by precipitation of intermediate sulfur phases at the margin of the zone with free sulfide are bordered by two distinct peaks in total organic sulfur (TOS). Organic matter sulfurization appears to precede pyrite formation in the iron-dominated margins of the sulfide zone, potentially linked to the presence of polysulfides formed by reaction between dissolved sulfide and elemental sulfur. Thus, SMTs can be hotspots for organic matter sulfurization in sulfide-limited, reactive iron-rich marine sedimentary systems. Furthermore, existence of elemental sulfur and iron monosulfide phases meters below the SMT demonstrates that in sulfide-limited systems metastable sulfur constituents are not readily converted to pyrite but can be buried to deeper sediment depths. Our data show that in non-steady state systems, redox zones do not occur in sequence but can reappear or proceed in inverse sequence throughout the sediment column, causing similar mineral alteration processes to occur at the same time at different sediment depths

Concomitant Caffeine Increases Binge Consumption of Ethanol in Adolescent and Adult Mice, But Produces Additive Motor Stimulation Only in Adolescent Animals

BACKGROUND: Binge co-consumption of highly caffeinated energy drinks with alcohol (ethanol [EtOH]) has become a common practice among adolescents/young adults and has been associated with an increased incidence of hazardous behaviors. Animal models are critical in advancing our understanding the neurobehavioral consequences of this form of binge drinking. Surprisingly, virtually no work has explored caffeine and EtOH co-consumption or its long-term consequences in adolescent animals. The primary objective of the current study was to extend a previously established mouse model of voluntary binge caffeine and EtOH co-consumption to explore adolescent consumption and responses compared to adults. METHODS: Adolescent and adult male C57BL/6J mice had daily limited access to caffeine (0.03% w/v), EtOH (20% v/v), a combined EtOH/caffeine solution, or water for 14 days via the binge-like drinking paradigm, drinking-in-the-dark (DID). Home cage locomotor activity was measured during DID in a subset of mice. Following DID, all mice rested for 18 days so that adolescents reached adulthood, whereupon all mice underwent 7 days of continuous access 2-bottle choice drinking for 10% (v/v) EtOH or water. RESULTS: Co-consumption with caffeine significantly increased EtOH intake and resultant blood ethanol concentrations in both adolescent and adult mice. In addition, adolescent mice exhibited a uniquely robust locomotor stimulant response to caffeine and EtOH co-consumption. Later EtOH intake and preference was not influenced, however, by prior fluid consumption history via DID. CONCLUSIONS: Together with findings from the human literature, our results suggest that caffeine co-consumption may positively influence binge alcohol consumption in adolescents/young adults. Importantly, this age group may be particularly sensitive to the additive stimulant effects of caffeinated alcohol consumption, an effect which may be related to the high incidence of associated negative outcomes in this population. These observations are particularly concerning considering the heightened plasticity of the adolescent brain

Application of the thorium fuel cycle

An economic analysis of the application of the thorium fuel cycle to thermal reactors is presented. (JWR