Spatial patterns of watershed impervious cover relativeto stream location

The urban stream syndrome may not be limited to streams in urbanized watersheds. We measured thespatial pattern of impervious cover in ∼82,800 small watersheds across the conterminous United Statesby comparing watershed-based and stream-based measures of imperviousness. The watershed-basedmeasure was the commonly used watershed percentage impervious cover. The stream-based measurewas the percentage of watershed stream length flowing through impervious cover. Spatial pattern ofimpervious cover was classified on a watershed basis as proximal to streams, distal to streams, and uni-form by comparing the two measures of impervious cover. We used a classification threshold of ±5%to assign watersheds to the three classes (i.e., stream-based minus watershed-based ≥5% = proximal;watershed-based minus stream-based ≥5% = distal; else = uniform). We then applied the classification totwo impervious cover thresholds, ≥5% and ≥15%. For ≥5% and ≥15% thresholds, impervious cover wasdistributed uniformly across ∼70% and ∼86% of the watersheds, respectively. For the remaining water-sheds, the proximal spatial pattern was ∼12x and ∼4x greater than the distal spatial pattern for the ≥5%and ≥15% impervious cover thresholds, respectively. The proximal spatial pattern of impervious coveroccurred predominantly in non-urbanized watersheds, resulting in a widespread occurrence of a rela-tively high percentage of streams flowing through relatively high impervious cover in watersheds wherethe total percentage impervious cover was relatively low. The spatial pattern of change in imperviouscover between ca. 2001 and ca. 2006 did not avoid streams. Impervious cover increased in the vicinitystreams in ∼55% of the watersheds with increases in impervious cover. During this period, the lengthof streams flowing through ≥5% and ≥15% impervious cover increased by ∼9800 km and ∼6900 km,respectively

Spatial patterns of watershed impervious cover relativeto stream location

The urban stream syndrome may not be limited to streams in urbanized watersheds. We measured thespatial pattern of impervious cover in ∼82,800 small watersheds across the conterminous United Statesby comparing watershed-based and stream-based measures of imperviousness. The watershed-basedmeasure was the commonly used watershed percentage impervious cover. The stream-based measurewas the percentage of watershed stream length flowing through impervious cover. Spatial pattern ofimpervious cover was classified on a watershed basis as proximal to streams, distal to streams, and uni-form by comparing the two measures of impervious cover. We used a classification threshold of ±5%to assign watersheds to the three classes (i.e., stream-based minus watershed-based ≥5% = proximal;watershed-based minus stream-based ≥5% = distal; else = uniform). We then applied the classification totwo impervious cover thresholds, ≥5% and ≥15%. For ≥5% and ≥15% thresholds, impervious cover wasdistributed uniformly across ∼70% and ∼86% of the watersheds, respectively. For the remaining water-sheds, the proximal spatial pattern was ∼12x and ∼4x greater than the distal spatial pattern for the ≥5%and ≥15% impervious cover thresholds, respectively. The proximal spatial pattern of impervious coveroccurred predominantly in non-urbanized watersheds, resulting in a widespread occurrence of a rela-tively high percentage of streams flowing through relatively high impervious cover in watersheds wherethe total percentage impervious cover was relatively low. The spatial pattern of change in imperviouscover between ca. 2001 and ca. 2006 did not avoid streams. Impervious cover increased in the vicinitystreams in ∼55% of the watersheds with increases in impervious cover. During this period, the lengthof streams flowing through ≥5% and ≥15% impervious cover increased by ∼9800 km and ∼6900 km,respectively

HA14-1 selectively induces apoptosis in Bcl-2-overexpressing leukemia/lymphoma cells, and enhances cytarabine-induced cell death

The Bcl-2 oncoprotein is commonly overexpressed in hematological malignancy, where it promotes the survival of neoplastic cells. Recently, a small molecule (HA14-1) was reported to bind the surface pocket of Bcl-2 that mediates antiapoptotic interactions, triggering apoptosis in a Bcl-2-transfected cell line. We investigated the activity of this compound in a panel of malignant hematopoietic cell lines. Consistent with its proposed role as a Bcl-2 inhibitor, HA14-1 was most cytotoxic in lines expressing high levels of Bcl-2. In addition, at lower concentrations (5–12.5 muM), the compound predominantly triggered apoptosis. However, at concentrations two-fold higher than this and above, increasing primary necrosis was observed, suggesting the onset of interactions supplementary to Bcl-2 inhibition. In experiments on primary cells, 25 muM HA14-1 induced extensive apoptosis in acute leukemic blasts, but also suppressed normal hematopoietic colony formation to <50% of baseline. Importantly, low-concentration HA14-1 (5 muM) was nontoxic to normal colony-forming cells, whereas it enhanced the cytotoxicity of the antileukemia drug cytarabine in Bcl-2-positive lymphoblastic leukemia cells. In conclusion, our results indicate that HA14-1 at low concentration selectively triggers apoptosis in malignant hematopoietic cells that overexpress Bcl-2. Agents of this class may have particular utility in combination with cytotoxic chemotherapy drugs

The chiral structure of porous chitin within the wing-scales of Callophrys rubi

The structure of the porous three-dimensional reticulated pattern in the wing scales of the butterfly Callophrys rubi (the Green Hairstreak) is explored in detail, via scanning and transmission electron microscopy. A full 3D tomographic reconstruction of a section of this material reveals that the predominantly chitin material is assembled in the wing scale to form a structure whose geometry bears a remarkable correspondence to the srs net, well-known in solid state chemistry and soft materials science. The porous solid is bounded to an excellent approximation by a parallel surface to the Gyroid, a three-periodic minimal surface with cubic crystallographic symmetry I4132, as foreshadowed by Stavenga and Michielson. The scale of the structure is commensurate with the wavelength of visible light, with an edge of the conventional cubic unit cell of the parallel-Gyroid of approximately 310 nm. The genesis of this structure is discussed, and we suggest it affords a remarkable example of templating of a chiral material via soft matter, analogous to the formation of mesoporous silica via surfactant assemblies in solution. In the butterfly, the templating is achieved by the lipid–protein membranes within the smooth endoplasmic reticulum (while it remains in the chrysalis), that likely form cubic membranes, folded according to the form of the Gyroid. The subsequent formation of the chiral hard chitin framework is suggested to be driven by the gradual polymerisation of the chitin precursors, whose inherent chiral assembly in solution (during growth) promotes the formation of a single enantiomer

Land cover change in Europe between 1950 and 2000 determined employing aerial photography

BIOPRESS (‘Linking Pan-European land cover change to pressures on Biodiversity’), a European Commission funded ‘Global Monitoring for Environment and Security’ project produced land cover change information (1950–2000) for Europe from aerial photographs and tested if this information is suitable for monitoring habitats and biodiversity. The methods and results related to the land cover change work are summarised. Changes in land cover were established through 73 window and 59 transect samples distributed across Europe. Although the sample size was too small and biased to represent the spatial variability observed in Europe, the work highlighted the importance of method consistency, the choice of nomenclature and spatial scale. The results suggest different processes are taking place in different parts of Europe: the Boreal and Alpine regions are dominated by forest management; abandonment and intensification are mainly encountered in the Mediterranean; urbanisation and drainage are more characteristic of the Continental and Atlantic regions