Quantitative determination of the number of surface active sites and the turnover frequency for methanol oxidation over bulk metal vanadates

The present work investigates the number and nature of the surface active sites, selectivity and turnover frequency towards methanol selective oxidation of a series of bulk metal vanadates. The catalysts were synthesized through an organic route and characterized by laser Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and specific surface area analysis (BET). The number of surface active sites (N_s) was determined by measuring the concentration of surface methoxy species adsorbed on the catalysts exposed to an atmosphere of 2000 ppm of methanol in helium at 100 °C. The specific activity values (TOFs) were calculated by normalizing the methanol oxidation reaction rate by the number of surface active sites probed by methanol chemisorption. The comparison of the methanol oxidation products distribution from bulk metal vanadates, pure V₂O₅ and corresponding metal oxides (NiO, MnO, etc.) strongly suggests that the metal vanadate catalysts consist of only surface vanadium oxide sites. The comparison of the TOF values demonstrated that bulk metal vanadates possess similar activity to monolayer vanadium oxide supported catalysts and are more active than bulk metal molybdates for methanol selective oxidation. Moreover, bulk metal vanadates are as active and selective as the commercial MoO₃/Fe₂(MoO₄)₃ catalysts at high methanol conversion.     

Increased availability and open probability of single L-type calcium channels from failing compared with nonfailing human ventricle

BACKGROUND: The role of the L-type calcium channel in human heart failure is unclear, on the basis of previous whole-cell recordings. METHODS AND RESULTS: We investigated the properties of L-type calcium channels in left ventricular myocytes isolated from nonfailing donor hearts (n= 16 cells) or failing hearts of transplant recipients with dilated (n=9) or ischemic (n=7) cardiomyopathy. The single-channel recording technique was used (70 mmol/L Ba2+). Peak average currents were significantly enhanced in heart failure (38.2+/-9.3 fA) versus nonfailing control hearts (13.2+/-4.5 fA, P=0.02) because of an elevation of channel availability (55.9+/-6.7% versus 26.4+/-5.3%, P=0.001) and open probability within active sweeps (7.36+/-1.51% versus 3.18+/-1.33%, P=0.04). These differences closely resembled the effects of a cAMP-dependent stimulation with 8-Br-cAMP (n= 11). Kinetic analysis of the slow gating shows that channels from failing hearts remain available for a longer time, suggesting a defect in the dephosphorylation. Indeed, the phosphatase inhibitor okadaic acid was unable to stimulate channel activity in myocytes from failing hearts (n=5). Expression of calcium channel subunits was measured by Northern blot analysis. Expression of alpha1c- and beta-subunits was unaltered. Whole-cell current measurements did not reveal an increase of current density in heart failure. CONCLUSIONS: Individual L-type calcium channels are fundamentally affected in severe human heart failure. This is probably important for the impairment of cardiac excitation-contraction coupling.     

Planning the post-communist city: Experiences from Sofia

This paper examines adjustments of the urban planning process to the post-communist context in the case of Sofia, the capital of Bulgaria. The main research question is whether master-planning processes have substantially changed from top-down and technocratic (as they certainly were in fascist and then communist Bulgaria) to open and participatory today. The paper tells the story of four master plans—one pre-communist, two communist, and one post-communist. It concludes that despite the increased capacity of the citizenry to both influence and challenge government planning and decision-making, there is little evidence of sharp discontinuity between past and present planning processes.     

Finite element analysis of the ring rolling process with integrated closed-loop control

In FEA of ring rolling processes the tools’ motions usually are defined prior to simulation. This procedure neglects the closed-loop control, which is used in industrial processes to control up to eight degrees of freedom (rotations, feed rates, guide rolls) in real time, taking into account the machine's performance limits as well as the process evolution. In order to close this gap in the new simulation approach all motions of the tools are controlled according to sensor values which are calculated within the FE simulation. This procedure leads to more realistic simulation results in comparison to the machine behaviour.     

Use of Modern High Strength Steels in Load Adapted Hydroformed B‐Pillars

The increase of legal and insurance demands on B‐pillars calls for high strength steels and new process chains. Therefore, the hydroforming of high strength close‐to‐contour tailored tubes to load adapted B‐pillars was investigated. Modern high strength steels were identified for the use in B‐pillars. Their forming and crash behaviour was predicted with the aid of validated numerical models. The accuracy of the numerical models was increased significantly by taking the forming history into account. The design of the hydroformed B‐pillar considered a product concept catalogue (i.e. package, functional areas, crash performance) close to a reference B‐pillar. As a reference the deep drawn B‐pillar of the Mercedes‐Benz W203 was chosen. Using high strength materials in the close‐to‐contour tailored tubes led to a significant reduction of the number of parts and the weight of the B‐pillar compared to the reference.     

Linking the proteins--elucidation of proteome-scale networks using mass spectrometry

Proteomes are intricate. Typically, thousands of proteins interact through physical association and post-translational modifications (PTMs) to give rise to the emergent functions of cells. Understanding these functions requires one to study proteomes as "systems" rather than collections of individual protein molecules. The abstraction of the interacting proteome to "protein networks" has recently gained much attention, as networks are effective representations, that lose specific molecular details, but provide the ability to see the proteome as a whole. Mostly two aspects of the proteome have been represented by network models: proteome-wide physical protein-protein-binding interactions organized into Protein Interaction Networks (PINs), and proteome-wide PTM relations organized into Protein Signaling Networks (PSNs). Mass spectrometry (MS) techniques have been shown to be essential to reveal both of these aspects on a proteome-wide scale. Techniques such as affinity purification followed by MS have been used to elucidate protein-protein interactions, and MS-based quantitative phosphoproteomics is critical to understand the structure and dynamics of signaling through the proteome. We here review the current state-of-the-art MS-based analytical pipelines for the purpose to characterize proteome-scale networks.     

The Devil Is in the Definitions

Problem: Traditional American zoning separates land uses, yet many urbanists and contemporary planners argue that bringing mixed use back to the American city is the key to restoring its vibrancy.

Purpose: This article compares the American and the German approaches to regulating land use.

Methods: I derive my conclusions from a review of German federal and local regulatory documents, and interviews I conducted in the German city of Stuttgart.

Results and conclusions: The U.S. zoning approach assumes that each land use district is suitable for only a single type of human activity, such as residential, commercial, or industrial use; whereas in Germany the prevailing principle is that each land use district is suitable for multiple types of activity, and most districts end up in mixed uses. Thus, despite some nominal similarities in the land use categories employed in both countries, the zoning methods are in fact starkly different.

Takeaway for practice: The German zoning system, which commonly mixes the land uses, challenges deeply engrained assumptions that underlie standard U.S. zoning, and it may offer useful alternatives for zoning reform.