Thermal Conversion of Guanylurea Dicyanamide into Graphitic Carbon Nitride via Prototype CNx Precursors

Guanylurea dicyanamide, [(H2N)C(-O)NHC(NH2)2][N(CN)2], has been synthesized by ion exchange reaction in aqueous solution and structurally characterized by single-crystal X-ray diffraction (C2/c, a = 2249.0(5) pm, b = 483.9(1) pm, c = 1382.4(3) pm, β = 99.49(3)°, V = 1483.8(5) × 106 pm3, T = 130 K). The thermal behavior of the molecular salt has been studied by thermal analysis, temperature-programmed X-ray powder diffraction, FTIR spectroscopy, and mass spectrometry between room temperature and 823 K. The results were interpreted on a molecular level in terms of a sequence of thermally induced addition, cyclization, and elimination reactions. As a consequence, melamine (2,4,6-triamino-1,3,5-triazine) is formed with concomitant loss of HNCO. Further condensation of melamine yields the prototypic CNx precursor melem (2,6,10-triamino-s-heptazine, C6N7(NH2)3), which alongside varying amounts of directly formed CNxHy material transforms into layered CNxHy phases without significant integration of oxygen into the core framework owing to the evaporation of HNCO. Thus, further evidence can be added to melamine and its condensation product melem acting as “key intermediates” in the synthetic pathway toward graphitic CNxHy materials, whose exact constitution is still a point at issue. Due to the characteristic formation process and hydrogen content a close relationship with the polymer melon is evident. In particular, the thermal transformation of guanylurea dicyanamide clearly demonstrates that the formation of volatile compounds such as HNCO during thermal decomposition may render a large variety of previously not considered molecular compounds suitable CNx precursors despite the presence of oxygen in the starting material

An open-label randomized clinical trial of prophylactic paracetamol coadministered with 7-valent pneumococcal conjugate vaccine and hexavalent diphtheria toxoid, tetanus toxoid, 3-component acellular pertussis, hepatitis B, inactivated poliovirus, and Haemophilus influenzae type b vaccine

BACKGROUND: In two clinical trials, low-grade fever was observed more frequently after coadministration than after separate administration of two recommended routine pediatric vaccines. Since fever is an important issue with vaccine tolerability, we performed this open-label study on the efficacy and safety of prophylactic use of paracetamol (acetaminophen, Benuron(R)) in children administered routine 7-valent pneumococcal conjugate vaccine (PCV-7) coadministered with hexavalent vaccine (diphtheria-tetanus-acellular pertussis-hepatitis B, polio, Haemophilus influenzae type b vaccine [DTPa-HBV-IPV/Hib]) in Germany. METHODS: Healthy infants (N = 301) who received a 3-dose infant series of PCV-7 and DTPa-HBV-IPV/Hib plus a toddler dose were randomly assigned 1:1 to prophylactic paracetamol (125 mg or 250 mg suppositories, based on body weight) at vaccination, and at 6--8 hour intervals thereafter, or a control group that received no paracetamol. Rectal temperature and local and other systemic reactions were measured for 4 days post vaccination; adverse events were collected throughout the study. RESULTS: In the intent-to-treat population, paracetamol reduced the incidence of fever >=38[degree sign]C, but this reduction was only significant for the infant series, with computed efficacy of 43.0% (95% confidence interval [CI]: 17.4, 61.2), and not significant after the toddler dose (efficacy 15.9%; 95% CI: -19.9, 41.3); results were similar in the per protocol (PP) population. Fever >39[degree sign]C was rare during the infant series, such that there were too few cases for assessment. After the toddler dose, paracetamol effectively reduced fever >39[degree sign]C, reaching statistical significance in the PP population only (efficacy 79%; 95% CI: 3.9, 97.7). Paracetamol also reduced reactogenicity, but there were few significant differences between groups after any dose. No vaccine-related serious adverse events were reported. CONCLUSIONS: Paracetamol effectively prevented fever and other reactions, mainly during the infant series. However, as events were generally mild and of no concern in either group our data support current recommendations to administer paracetamol to treat symptoms only and not for routine prophylaxis.Trial registration: NCT00294294

Succession of the sea-surface microlayer in the coastal Baltic Sea under natural and experimentally induced low-wind conditions

The sea-surface microlayer (SML) is located within the boundary between the atmosphere and hydrosphere. The high spatial and temporal variability of the SML's properties, however, have hindered a clear understanding of interactions between biotic and abiotic parameters at or across the air-water interface. Among the factors changing the physical and chemical environment of the SML, wind speed is an important one. In order to examine the temporal effects of minimized wind influence, SML samples were obtained from the coastal zone of the southern Baltic Sea and from mesocosm experiments in a marina to study naturally and artificially calmed sea surfaces. Organic matter concentrations as well as abundance, (3)H-thymidine incorporation, and the community composition of bacteria in the SML (bacterioneuston) compared to the underlying bulk water (ULW) were analyzed. In all SML samples, dissolved organic carbon and nitrogen were only slightly enriched and showed low temporal variability, whereas particulate organic carbon and nitrogen were generally greatly enriched and highly variable. This was especially pronounced in a dense surface film (slick) that developed during calm weather conditions as well as in the artificially calmed mesocosms. Overall, bacterioneuston abundance and productivity correlated with changing concentrations of particulate organic matter. Moreover, changes in the community composition in the field study were stronger in the particle-attached than in the non-attached bacterioneuston. This implies that decreasing wind enhances the importance of particle-attached assemblages and finally induces a succession of the bacterial community in the SML. Eventually, under very calm meteorological conditions, there is an uncoupling of the bacterioneuston from the ULW

Aristida acuminata Hack.

Campo dos SerevospublishedVersio

Vier Jahre ökologischer Anbau landwirtschaftlicher Kulturen – Erträge und Qualitäten im Vergleich –

The quality of agricultural products grown organically or conventionally under the same environmental conditions is extensively investigated and compared over several years. Investigations should result in statements about the suitability of varieties for the production of specific qualities and the possibility of their improvement in organic farming

Einsatz von gekeimtem Getreide als Futtermittel

Die EU-Verordnung 1804/1999 regelt die Einbeziehung der tierischen Erzeugung in den Geltungsbereich der Verordnung (EWG) Nr. 2092/91 über den ökologischen Landbau und die entsprechende Kennzeichnung der landwirtschaftlichen Erzeugnisse und Lebensmittel. Danach müssen im ökologischen Landbau alle Tiere nach den Grundregeln dieser Verordnung gehalten werden. Das Futter soll den ernährungsphysiologischen Bedarf der Tiere decken und aus dem ökologischen Anbau stammen. Dafür dürfen bis August 2005 im begrenzten Umfang konventionelle Futtermittel zugesetzt werden, wenn eine ausschließliche Versorgung mit Futtermitteln aus dem ökologischen Anbau nicht möglich ist. Für die Geflügelfütterung bedeutet das einen zulässigen Höchstanteil an konventionellem Futter von 20% im Jahr (max. 25% Trockenmasse am Tag). Bislang werden dafür besonders die konventionellen Komponenten Maiskleber und Kartoffeleiweiß, die als Nebenprodukte bei der Stärkegewinnung anfallen, eingesetzt. Vergleichbare ökologische Produkte sind z. Z. nicht verfügbar. Unter diesem Aspekt ist zu klären, ob eine ausreichende Nährstoff- und Eiweißversorgung über den Einsatz von 20% Getreidekeimlingen in der Futterration gewährleistet werden kann, die damit zu 100% ökologischer Herkunft ist. In einem, im Rahmen des Bundesprogramms ökologischer Landbau, geförderten Projekt werden alle nachfolgend aufgeführten Parameter analysiert. Proteine, Stärken, Nichtstärkepolysaccharide, Zucker und Fette als wertgebende Inhaltsstoffe sowie Auswuchs, Pilzbefall und Mykotoxine als dominierende Schadfaktoren in Getreide stehen dabei im Mittelpunkt des Interesses. Ziel ist es, Kriterien für die optimale Prozessführung der Keimung und eine hohe Produktqualität der Keimlinge zu sichern, um eine hochwertige Futterkomponente aus dem ökologischen Landbau für die Tierernährung bereitzustellen