ALBERT

Description: A series of chalcogenidoantimonates, namely [Zn(NH 3 ) 6 ](Sb III 4 S 7 ) ( 1 ), [Zn(NH 3 ) 6 ]{Zn(NH 3 ) 3 Sb V S 4 } 2 · NH 3 ( 2 ), [Mn(NH 3 ) 6 ](Sb III Se 2 ) 2 ( 3 ) and [Zn(NH 3 ) 4 ]{Zn(NH 3 )Sb III Se 3 } 2 · 3NH 3 ( 4 ) are synthesized by solvothermal technique in liquid ammonia at 50 °C from elemental zinc or manganese, antimony and sulfur or selenium. 1 (space group P ) and 2 ( P ) crystallize centrosymmetrically, whereas 3 ( Pna 2 1 ) and 4 ( P 2 1 ) represent polar structures. All compounds contain discrete cationic [Zn(NH 3 ) 4 ] 2+ , [Zn(NH 3 ) 6 ] 2+ , and [Mn(NH 3 ) 6 ] 2+ ammine complexes. In the anionic structure parts, corner-connected trigonal-pyramidal SbS 3 and SbSe 3 are the characteristic building units. 1 and 4 contain 2D polymeric anions, in the latter case with Zn 2+ cations incorporated in a selenidoantimonate(III) network. The polymeric anion in the structure of 3 is a helical chain. 2 is a molecular compound and contains dinuclear anions [S 3 Sb–S–Zn(NH 3 ) 3 ] 2– with Sb V . Raman measurements show the Sb–Ch valence vibrations in the expected region between 250–370 cm –1 for 1 and at 212 cm –1 for 4 . According to the reflectance spectrum 4 is a semiconductor with an optical band gap of 2.05(5) eV.

Description: With Sharpless' and Meldal's discovery of the immensely supportive effect that metal catalysis has on Huisgen's classical 1,3-dipolar cycloaddition, azides (RN 3 ) – long underappreciated in organic synthesis – suddenly got in the focus of attention as most crucial players in sensational ‘click chemistry'. Less noisy though with the same commitment and even a much broader scope of scientific topics and objectives, the inorganic azide chemistry has made just as great strides in the last few decades. This review (Part I) gives an introductory survey of the most important results, and informs about modern developments and general trends. Particular emphasis is placed on the recent successful approaches to highly unstable homoleptic azido metal complexes of the main group and early transition elements, as well as on the enormous structural versatility caused by the ‘flexidentate' N 3 – ligand with its unsurpassed bridging capacities. The presentation in this paper of selected compounds and reactions is meant, in a way, as a prelude to the [3+2]-cycloadditions of metal azides and related species which will be covered in-depths in Part II. A large part of the comments finally deals with applications in fields such as catalysis, high explosive performance or magnetism of metal compounds containing azide, today certainly one of the most attractive research areas world-wide.

Description: [1]  We have measured the bidirectional reflectance of analogs of dry, wet and frozen Martian soils over a wide range of phase angles in the visible spectral range. All samples were produced from two geologic samples: the standard JSC Mars-1 soil simulant and Hawaiian basaltic sand. In a first step, experiments were conducted with the dry samples to investigate the effects of surface texture. Comparisons with results independently obtained by different teams with similar samples showed a satisfying reproducibility of the photometric measurements as well as a noticeable influence of surface textures resulting from different sample preparation procedures. In a second step, water was introduced to produce wet and frozen samples and their photometry investigated. Optical microscope images of the samples provided information about their micro-texture. Liquid water, even in relatively low amount, resulted in the disappearance of the backscattering peak and the appearance of a forward scattering peak whose intensity increases with the amount of water. Specular reflections only appeared when water was present in an amount large enough to allow water to form a film at the surface of the sample. Icy samples showed a wide variability of photometric properties depending on the physical properties of the water ice. We discuss the implications of these measurements in terms of the expected photometric behavior of the Martian surface, from equatorial to circum-polar regions. In particular, we propose some simple photometric criteria to improve the identification of wet and/or icy soils from multiple observations under different geometries.

Description: Recent studies have suggested that changes in serum phosphate levels influence pathological states associated with aging such as cancer, bone metabolism, and cardiovascular function, even in individuals with normal renal function. The causes are only beginning to be elucidated but are likely a combination of endocrine, paracrine, autocrine, and cell autonomous effects. We have used an integrated quantitative biology approach, combining transcriptomics and proteomics to define a multi-phase, extracellular phosphate-induced, signaling network in pre-osteoblasts as well as primary human and mouse mesenchymal stromal cells. We identified a rapid mitogenic response stimulated by elevated phosphate that results in the induction of immediate early genes including c-fos . The mechanism of activation requires FGF receptor signaling followed by stimulation of N-ras and activation of AP-1 and serum response elements. A distinct long-term response also requires FGF receptor signaling and results in N-ras activation and expression of genes and secretion of proteins involved in matrix regulation, calcification, and angiogenesis. The late response is synergistically enhanced by addition of FGF23 peptide. The intermediate phase results in increased oxidative phosphorylation and ATP production and is necessary for the late response providing a functional link between the phases. Collectively, the results define elevated phosphate, as a mitogen and define specific mechanisms by which phosphate stimulates proliferation and matrix regulation. Our approach provides a comprehensive understanding of the cellular response to elevated extracellular phosphate, functionally connecting temporally coordinated signaling, transcriptional, and metabolic events with changes in long-term cell behavior. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.

Description: ABSTRACT The ability of circulation type classifications (CTCs) to resolve surface climatic and environmental variables is essential with respect to their application in synoptic climatological applications. This ‘synoptic skill’ depends on several factors including inherent properties of classification methods but as well varying boundary conditions. In this contribution the relevance of the size of the spatial domain for which CTCs are derived is investigated. To this end varying automated CTCs are applied to daily gridded sea level pressure data for 1950–2010 and in each case eight spatial domains of varying size centred around 44 locations spread over the greater north Atlantic European region. For the resulting more than 7000 CTCs the synoptic skill for daily temperature and precipitation taken from the E-OBS v4.0 data set has been estimated using varying evaluation metrics. Resulting values of evaluation metrics aggregated according to varying domain sizes reveal a distinct influence of the size of the domain on the synoptic skill of CTCs. In general highest skill appears to be achieved for domain sizes with a horizontal dimension of roughly 1300–1800 km (in west–east direction) thus covering most frequent size ranges of synoptic scale systems. However, optimal domain sizes tend to be smaller for precipitation (compared to temperature) in summer (compared to winter) and in more continental regions (compared to more oceanic regions). Distinct deviations from the overall finding of relatively small optimal domains emerge for temperatures above/below certain thresholds for which in certain locations and seasons continental scale domains yield highest synoptic skill. Finally the comparison of varying CTCs concerning the effect of the domain size for synoptic skill shows marked differences between methods and moreover clearly elucidates that differences in synoptic skill that can be attributed to varying domain sizes reach comparable magnitude than those related to differing methods. Copyright © 2013 Royal Meteorological Society

Description: A multi-proxy record is presented for approximately the last 4500 cal a BP from Lake Shkodra, Albania/Montenegro. Lithological analyses, C/N ratio and δ 13 C of the organic and inorganic carbon component suggest that organic matter and bulk carbonate are predominantly authigenic. The δ 18 O record of bulk carbonate indicates the presence of two prominent wet periods: one at ca. 4300 cal a BP and one at ca. 2500–2000 cal a BP. The latter phase is also found in southern Spain and Central Italy, and represents a prominent event in the western and central Mediterranean. In the last 2000 years, four relatively wet intervals occurred between ca. 1800 and 1500 cal a BP (150–450 AD), 1350–1250 (600–700 AD), 1100–800 (850–1150 AD), and at ca. 90 cal a BP (1860 AD). Between ca. 4100 and 2500 cal a BP δ 18 O values are relatively high, with three prominent peaks indicating drier conditions at ca. 4100–4000 cal a BP, ca. 3500 and at ca. 3300 cal a BP. Four additional drier events are identified at 1850 (ca. 100 AD), 1400 (ca. 550 AD), 1150 (800 AD) and ca.750 cal a BP (1200 AD). The pollen record does not show changes in accordance with these episodes owing to the poor sensitivity of vegetation in this area, which is dominated by an orographic rainfall effect and where changes in altitudinal vegetation belts do not affect the pollen rain in the lake catchment. However, since ca. 900 cal a BP a significant decrease in the percentage arboreal pollen and in pollen concentrations suggest major deforestation produced by human activities. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The ‘Millennium Drought’ (2001–2009) can be described as the worst drought on record for southeast Australia. Adaptation to future severe droughts requires insight into the drivers of the drought and its impacts. These were analyzed using climate, water, economic and remote sensing data combined with biophysical modeling. Prevailing El Niño conditions explained about two-thirds of rainfall deficit in east Australia. Results for south Australia were inconclusive; a contribution from global climate change remains plausible but unproven. Natural processes changed the timing and magnitude of soil moisture, streamflow and groundwater deficits by up to several years, and caused the amplification of rainfall declines in streamflow to be greater than in normal dry years. By design, river management avoided impacts on some categories of water users, but did so by exacerbating the impacts on annual irrigation agriculture and, in particular, river ecosystems. Relative rainfall reductions were amplified 1.5–1.7 times in dryland wheat yields, but the impact was offset by steady increases in cropping area and crop water use efficiency (perhaps partly due to CO2 fertilization). Impacts beyond the agricultural sector occurred (e.g., forestry, tourism, utilities) but were often diffuse and not well quantified. Key causative pathways from physical drought to the degradation of ecological, economic and social health remain poorly understood and quantified. Combined with the multiple dimensions of multi-year droughts and the specter of climate change, this means future droughts may well break records in ever new ways and not necessarily be managed better than past ones.

Description: Neutral halogenido nitrosyl metal complexes and their history are reviewed. The mass spectra indicate the dimeric nature of [(ON)Ni(μ-I) 2 Ni(NO)] and of [(ON)Pd(μ-Cl)Pd(NO)] whereas hitherto a tetramer was favored for nitrosyl nickel iodide.