A shape changing tandem Rh(CNC) catalyst: Preparation of bicyclo[4.2.0]octa- 1,5,7-trienes from terminal aryl alkynes

The preparation of a range of tetraaryl-substituted bicyclo[4.2.0]octa-1,5,7-trienes using a one-pot procedure starting from terminal aryl alkynes and catalysed by a rhodium(i) complex is reported. This synthesis proceeds by a reaction sequence involving head-to-tail homocoupling of the terminal alkyne and zipper annulation of the resulting gem-enyne. The rhodium catalyst employed is notable for the incorporation of a flexible NHC-based pincer ligand, which is suggested to interconvert between mer- and fac-coordination modes to fulfil the orthogonal mechanistic demands of the two transformations. Evidence for this interesting auto-tandem action of the catalyst is provided by reactions of the precatalyst with model substrates, corroborating proposed intermediates in both component cycles, and norbornadiene, which reversibly captures the change in pincer ligand coordination mode, along with a DFT-based computational analysis

A Concept for a Mars Boundary Layer Sounding Balloon: Science Case, Technical Concept and Deployment Risk Analysis

The Mars Exploration Program Analysis Group has identified measurements of the state and the variability of the Martian atmosphere as high priority investigations for the upcoming years. Balloon-borne instruments could bridge the gap in both temporal and spatial resolution in mesoscale distances between local, stationary landers and global orbiter observations. The idea to use a balloon system for such a purpose is not new in essence and has been proposed already in past decades. While those concepts considered an aerial deployment during entry and descent, the concept outlined in this study revisits a launch off the payload deck of a lander from the Martian surface. This deployment option profits today mainly from the technological advance in micro-electronics and sensor miniaturization, which enables the design of a balloon-probe significantly smaller than earlier proposed systems. This paper presents the feasibility assessment for this instrument and gives further details on the scientific and operational concept, a strawman sensor suite, its system components and the associated size and budget estimates. It is complemented by the analysis scheme proposed to assess, manage and mitigate the deployment risk involved in automatically launching such a balloon-system off a planetary surface

Handling the phosphorus paradox in agriculture and natural ecosystems: scarcity, necessity, and burden of P

This special issue of Ambio compiles a series of contributions made at the 8th International Phosphorus Workshop (IPW8), held in September 2016 in Rostock, Germany. The introducing overview article summarizes major published scientific findings in the time period from IPW7 (2015) until recently, including presentations from IPW8. The P issue was subdivided into four themes along the logical sequence of P utilization in production, environmental, and societal systems: (1) Sufficiency and efficiency of P utilization, especially in animal husbandry and crop production; (2) P recycling: technologies and product applications; (3) P fluxes and cycling in the environment; and (4) P governance. The latter two themes had separate sessions for the first time in the International Phosphorus Workshops series; thus, this overview presents a scene-setting rather than an overview of the latest research for these themes. In summary, this paper details new findings in agricultural and environmental P research, which indicate reduced P inputs, improved management options, and provide translations into governance options for a more sustainable P use

Nephron-specific expression of components of the renin–angiotensin–aldosterone system in the mouse kidney

Introduction: The renin–angiotensin–aldosterone system (RAAS) plays an integral role in the regulation of blood pressure, electrolyte and fluid homeostasis in mammals. The capability of the different nephron segments to form components of the RAAS is only partially known. This study therefore aimed to characterize the nephron-specific expression of RAAS components within the mouse kidney. Materials and methods: Defined nephron segments of adult C57B/16 mice were microdissected after collagenase digestion. The gene expression of renin, angiotensinogen (AGT), angiotensin-converting enzyme (ACE), angiotensin II receptors 1a (AT1a), 1b (AT1b), and 2 (AT2) was assessed by reverse transcriptase polymerase chain reaction (RT-PCR). Results: Renin mRNA was present in glomeruli, in proximal tubules, in distal convoluted tubules (DCT) and cortical collecting ducts (CCD). AGT mRNA was found in proximal tubules, descending thin limb of Henle’s loop (dTL) and in the medullary part of the thick ascending limb (mTAL). ACE mRNA was not detectable in microdissected mouse nephron segments. AT1a, AT1b and AT2 mRNA was detected in glomeruli and proximal convoluted tubules. Conclusions: Our data demonstrate a nephron-specific distribution of RAAS components. All components of the local RAAS – except ACE – are present in proximal convoluted tubules, emphasizing their involvement in sodium and water handling

Ein neuer Gesellschaftsvertrag für eine nachhaltige Landwirtschaft

Die Landwirtschaft in Deutschland, Europa und weltweit befindet sich in einem dramatischen Umbruchprozess. Einerseits bieten Liberalisierung und Marktöffnung, neue technologische Entwicklungen, die wachsende Weltbevölkerung und neue Kundenwünsche vielen landwirtschaftlichen Betrieben neue Möglichkeiten. Andererseits stehen viele Landwirtinnen und Landwirte in internationaler Konkurrenz, sind zum betrieblichen Wachstum mit hohem Investitionsrisiko gezwungen, sind Teil strikt regulierter Wertschöpfungsketten und müssen steigenden gesellschaftlichen Ansprüchen genügen. Zugleich machen sich viele Menschen Sorgen, dass die Prozesse der Rationalisierung und Modernisierung der landwirtschaftlichen Produktion auf Kosten von Natur-, Umwelt- und Tierschutz gehen. Auf vielen Ebenen wird daher bereits nach einer neuen Verständigung darüber gesucht, was die Gesellschaft von der Landwirtschaft erwartet, und welche Unterstützung die Landwirtinnen und Landwirte im Gegenzug dafür erwarten dürfen. Vor diesem Hintergrund entwickelt das vorliegende Open Access-Buch eine wissenschaftlich fundierte Kritik der Umweltauswirkungen der Landwirtschaft und der politischen Logik der Agrarpolitik. Es präsentiert ein neues Leitbild mit konkreten Indikatoren sowie alternative strategische Handlungsoptionen. Die umfassende Analyse wird zu einem Vorschlag für eine neue Architektur der europäischen Agrarpolitik gebündelt, die eine breite Diskussion um einen Neuen Gesellschaftsvertrag für die Landwirtschaft in Deutschland und Europa anstoßen soll

Ein neuer Gesellschaftsvertrag für eine nachhaltige Landwirtschaft

Die Landwirtschaft in Deutschland, Europa und weltweit befindet sich in einem dramatischen Umbruchprozess. Einerseits bieten Liberalisierung und Marktöffnung, neue technologische Entwicklungen, die wachsende Weltbevölkerung und neue Kundenwünsche vielen landwirtschaftlichen Betrieben neue Möglichkeiten. Andererseits stehen viele Landwirtinnen und Landwirte in internationaler Konkurrenz, sind zum betrieblichen Wachstum mit hohem Investitionsrisiko gezwungen, sind Teil strikt regulierter Wertschöpfungsketten und müssen steigenden gesellschaftlichen Ansprüchen genügen. Zugleich machen sich viele Menschen Sorgen, dass die Prozesse der Rationalisierung und Modernisierung der landwirtschaftlichen Produktion auf Kosten von Natur-, Umwelt- und Tierschutz gehen. Auf vielen Ebenen wird daher bereits nach einer neuen Verständigung darüber gesucht, was die Gesellschaft von der Landwirtschaft erwartet, und welche Unterstützung die Landwirtinnen und Landwirte im Gegenzug dafür erwarten dürfen. Vor diesem Hintergrund entwickelt das vorliegende Open Access-Buch eine wissenschaftlich fundierte Kritik der Umweltauswirkungen der Landwirtschaft und der politischen Logik der Agrarpolitik. Es präsentiert ein neues Leitbild mit konkreten Indikatoren sowie alternative strategische Handlungsoptionen. Die umfassende Analyse wird zu einem Vorschlag für eine neue Architektur der europäischen Agrarpolitik gebündelt, die eine breite Diskussion um einen Neuen Gesellschaftsvertrag für die Landwirtschaft in Deutschland und Europa anstoßen soll

PLANETA ARTE: desenhando e compartilhando arte através de um ambiente virtual de aprendizagem

O presente artigo apresenta o Planeta Arte, no que se refere ao contexto envolvido, fundamentação teórica, questões técnicas, pedagógicas e de design. Trata-se de uma funcionalidade do ambiente virtual de aprendizagem PLANETA ROODA, disponívelem http://www.nuted.edu.ufrgs.br/planetarooda, o qual é destinado à Educação Infantil e Anos Iniciais

Association of eGFR-Related Loci Identified by GWAS with Incident CKD and ESRD

Family studies suggest a genetic component to the etiology of chronic kidney disease (CKD) and end stage renal disease (ESRD). Previously, we identified 16 loci for eGFR in genome-wide association studies, but the associations of these single nucleotide polymorphisms (SNPs) for incident CKD or ESRD are unknown. We thus investigated the association of these loci with incident CKD in 26,308 individuals of European ancestry free of CKD at baseline drawn from eight population-based cohorts followed for a median of 7.2 years (including 2,122 incident CKD cases defined as eGFR <60ml/min/1.73m2 at follow-up) and with ESRD in four case-control studies in subjects of European ancestry (3,775 cases, 4,577 controls). SNPs at 11 of the 16 loci (UMOD, PRKAG2, ANXA9, DAB2, SHROOM3, DACH1, STC1, SLC34A1, ALMS1/NAT8, UBE2Q2, and GCKR) were associated with incident CKD; p-values ranged from p = 4.1e-9 in UMOD to p = 0.03 in GCKR. After adjusting for baseline eGFR, six of these loci remained significantly associated with incident CKD (UMOD, PRKAG2, ANXA9, DAB2, DACH1, and STC1). SNPs in UMOD (OR = 0.92, p = 0.04) and GCKR (OR = 0.93, p = 0.03) were nominally associated with ESRD. In summary, the majority of eGFR-related loci are either associated or show a strong trend towards association with incident CKD, but have modest associations with ESRD in individuals of European descent. Additional work is required to characterize the association of genetic determinants of CKD and ESRD at different stages of disease progression

Integration of genome-wide association studies with biological knowledge identifies six novel genes related to kidney function

In conducting genome-wide association studies (GWAS), analytical approaches leveraging biological information may further understanding of the pathophysiology of clinical traits. To discover novel associations with estimated glomerular filtration rate (eGFR), a measure of kidney function, we developed a strategy for integrating prior biological knowledge into the existing GWAS data for eGFR from the CKDGen Consortium. Our strategy focuses on single nucleotide polymorphism (SNPs) in genes that are connected by functional evidence, determined by literature mining and gene ontology (GO) hierarchies, to genes near previously validated eGFR associations. It then requires association thresholds consistent with multiple testing, and finally evaluates novel candidates by independent replication. Among the samples of European ancestry, we identified a genome-wide significant SNP in FBXL20 (P = 5.6 × 10−9) in meta-analysis of all available data, and additional SNPs at the INHBC, LRP2, PLEKHA1, SLC3A2 and SLC7A6 genes meeting multiple-testing corrected significance for replication and overall P-values of 4.5 × 10−4-2.2 × 10−7. Neither the novel PLEKHA1 nor FBXL20 associations, both further supported by association with eGFR among African Americans and with transcript abundance, would have been implicated by eGFR candidate gene approaches. LRP2, encoding the megalin receptor, was identified through connection with the previously known eGFR gene DAB2 and extends understanding of the megalin system in kidney function. These findings highlight integration of existing genome-wide association data with independent biological knowledge to uncover novel candidate eGFR associations, including candidates lacking known connections to kidney-specific pathways. The strategy may also be applicable to other clinical phenotypes, although more testing will be needed to assess its potential for discovery in genera