Quantum transport through STM-lifted single PTCDA molecules

Using a scanning tunneling microscope we have measured the quantum conductance through a PTCDA molecule for different configurations of the tip-molecule-surface junction. A peculiar conductance resonance arises at the Fermi level for certain tip to surface distances. We have relaxed the molecular junction coordinates and calculated transport by means of the Landauer/Keldysh approach. The zero bias transmission calculated for fixed tip positions in lateral dimensions but different tip substrate distances show a clear shift and sharpening of the molecular chemisorption level on increasing the STM-surface distance, in agreement with experiment.Comment: accepted for publication in Applied Physics

Apartment house in Pelhřimov

Bakalářská práce řeší projektovou dokumentaci pro provedení stavby novostavby bytového domu v Pelhřimově. Jedná se o částečně podsklepený objekt se dvěma nadzemními podlažími. V bytovém domě je celkem navrženo pět bytů. Ke každému bytu náleží jedna sklepní kóje v suterénu. Svislé nosné zdivo je z keramických tvárnic POTOTHERM doplněných kontaktním zateplovacím systémem. Objekt je zastřešen jednoplášťovou plochou střechou s kačírkem.Bachelor thesis deals with documentation for the execution of the construction of new building apartment house in Pelhřimov. It is the house with two above-ground floors with partial basement. The apartment building has five flats. Every flat has one cellar in basement. The loadbearing masonry is designed from clay bricks POTOTHERM with contact thermal insulaton system. The objekt is roofed with a flat roof with a pea gravel.

Object-mediated learning and strategic renewal in a mature organization

Knowledge transformation between practice-based communities is reported through a 2-year longitudinal case study. The company, PresMed, was transformed from a moribund and divided organization to one where different practice-based communities engaged in collective learning. However, the transformation involved conflict, politics and power to overcome the influence of localized and embedded knowledge. The nature of practice-based learning means investment in past activities and different organizational communities create tensions. It is suggested that mediating artefacts, or boundary objects, provide an opportunity to develop new shared conceptions of activity and new modes of action. However, at the heart of this transformation, communication, politics and power are central to pragmatic engagement in new practices. Thus, it is the social activities and the political will and skill to influence, cajole and institutionalize systemic changes and not the artefacts or objects per se that are at the heart of knowledge transformation

Spontaneous recovery from micronodular cirrhosis: evidence for incomplete resolution associated with matrix cross-linking

Background & Aims: Liver fibrosis and cirrhosis result from the excessive secretion of matrix proteins by hepatic stellate cells (HSCs). Previously considered irreversible, we have studied a model of cirrhosis to determine the mechanisms mediating and limiting spontaneous recovery. Methods: A micronodular cirrhosis was induced in rats after 12 weeks of CCl4 intoxication. Livers were analyzed for evidence of matrix degradation, matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) expression, stellate cell apoptosis, tissue transglutaminase (tTg) expression, and matrix cross-linking during spontaneous recovery of up to 366 days. Results: Over 366 days of recovery, micronodular cirrhosis underwent significant remodeling to a macronodular cirrhosis. Expression of collagen-1 and TIMP messenger RNA (mRNA) decreased significantly and active MMPs were shown in livers during remodeling of fibrosis. Resolution also was characterized by apoptosis of HSCs, predominantly at the margins of fibrotic septa. Residual septa, not remodeled at 366 days, were characterized by tTg-mediated cross-linking and relative hypocellularity. Conclusion: Recovery from comparatively advanced cirrhosis is possible and results in remodeling from a micronodular cirrhosis to a macronodular cirrhosis. We suggest resolution is limited by tTg-mediated matrix cross-linking and a failure of HSC apoptosis

The Art of Scenario Design

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69119/2/10.1177_003755007234004.pd

Nitrogen deposition and climate effects on soil nitrogen availability: influences of habitat type and soil characteristics

The amount of plant-available nitrogen (N) in soil is an important indicator of eutrophication of semi-natural habitats, but previous studies have shown contrasting effects of N deposition on mineralisable N in different habitats. The stock of readily mineralisable N (Nrm) was measured in 665 locations across Britain from a range of intensively and extensively managed habitats, allowing N availability to be studied in relation to soil and vegetation type, and also to variation in climate and in reactive N deposition from the atmosphere. Mineralisable N contents were correlated with deposition in extensively managed habitats but not in intensively managed habitats. The following statements apply only to extensively managed habitats. All habitats showed a similar increase in Nrm with N deposition. However, soil characteristics affected the relationship, and soil carbon content in particular was a major control on mineralisation. The Nrm stock increased more with N deposition in organic than in mineral soils. The nitrate proportion of Nrm also increased with N deposition but, conversely, this increase was greater in mineral than in organic soils. The measurements could be used as indicators of eutrophication, e.g. deposition rates of over 20 kg N ha− 1 y− 1 are associated with nitrate proportions of > 41% in a mineral soil (2% carbon), and with Nrm stocks of over 4.8 kg N ha− 1 in an organic soil (55% carbon). Both Nrm and nitrate proportion increased with mean annual temperature of the sampling location, despite consistent incubation temperature, suggesting that increasing temperatures are likely to increase the eutrophying effects of N pollution on semi-natural ecosystems