Entwicklung und Erprobung eines Verfahrens zur Untergrundentsäuerung von Kippengrundwässern

Sulfate-reducing processes were initiated in an aquifer with AMD-laden groundwater orthogonally to the located main groundwater flow direction. Groundwater was intermittently circulated between two wells. Substrate (methanol) and nutrients were added to this flow. After one year a sulphate-reducing reactor was formed in the aquifer, that precipitated FeS and decreased the acidity. These effects could still be observed one year after cessation of substrate amendment.     

Simple colorimetric method for quantification of surface carboxy groups on polymer particles

We present a novel, simple, and fast colorimetric method to quantify the total number of carboxy groups on polymer microparticle and nanoparticle surfaces. This method exploits that small divalent transition metal cations (M(2+) = Ni(2+), Co(2+), Cd(2+)) are efficiently bound to these surface functional groups, which allows their extraction by a single centrifugation step. Remaining M(2+) in the supernatant is subsequently quantified spectrophotometrically after addition of the metal ion indicator pyrocatechol violet, for which Ni(2+) was identified to be the most suitable transition metal cation. We demonstrate that the difference between added and detected M(2+) is nicely correlated to the number of surface carboxy groups as determined by conductometry, thereby affording a validated measure for the trueness of this procedure. The variation coefficient of ~5% found in reproducibility studies underlines the potential of this novel method that can find conceivable applications for the characterization of different types of poly(carboxylic acid)-functionalized materials, e.g., for quality control by manufacturers of such materials.     

Influence of dynamic stimulation,visual perception and individual susceptibility to car sickness during controlled stop-and-go driving

Forschung im Ingenieurwesen - The enjoyment and usage of highly automated vehicles might be reduced by motion sickness. This study addresses the influencing factors of dynamic stimulation, visual...     

Role of social desirability in personality testing for personnel selection: The red herring.

Response bias continues to be the most frequently cited criticism of personality testing for personnel selection. The authors meta-analyzed the social desirability literature, examining whether social desirability functions as a predictor for a variety of criteria, as a suppressor, or as a mediator. Social desirability scales were found not to predict school success, task performance, counterproductive behaviors, and job performance. Correlations with the Big Five personality dimensions, cognitive ability, and years of education are presented along with empirical evidence that (a) social desirability is not as pervasive a problem as has been anticipated by industrial-organizational psychologists, (b) social desirability is in fact related to real individual differences in emotional stability and conscientiousness, and (c) social desirability does not function as a predictor, as a practically useful suppressor, or as a mediator variable for the criterion of job performance. Removing the effects of social desirability from the Big Five dimensions of personality leaves the criterion-related validity of personality constructs for predicting job performance intact. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Entwurf von Flüssigkeitsbehältern

Design of Liquid Retaining Structures – Remarks on the Rules of the Guideline “Watertight Concrete” The use of watertight concrete structures is regulated by the guideline “Watertight Concrete” of the German Committee of Reinforced Concrete, especially requirements on the serviceability limit states. The scope of the guideline is valid for liquid retaining structures too. The essential characteristic of those structures is their defined tightness. Design concepts in order to fullfill requirements on durability of concrete tanks are discussed. Moreover, recommendations due to the design of moderate prestressed reinforced concrete tanks are given, containing the durable filling of planned cracks. Design aspects of the European Standard EC 2 Part 3 are discussed too.     

Membranbrennstoffzellen

With the development of polymer membranes suitable as proton‐conducting electrolytes, membrane fuel cells are now successfully applied in various areas. Depending on the application, the service life, the power density or other system aspects are optimized. Common to all applications is the requirement to reduce costs, which, however, plays a decisive role especially in passenger cars. The development of the membrane fuel cell has now reached a high technical level, but political flanking measures are still required to launch it on the market. This applies both to the hydrogen infrastructure for fuel cell vehicles and to the promotion of fuel cell‐based combined heat and power generation.     

Metal–Organic Framework Nanoparticles Induce Pyroptosis in Cells Controlled by the Extracellular pH

Ion homeostasis is essential for cellular survival, and elevated concentrations of specific ions are used to start distinct forms of programmed cell death. However, investigating the influence of certain ions on cells in a controlled way has been hampered due to the tight regulation of ion import by cells. Here, it is shown that lipid-coated iron-based metal–organic framework nanoparticles are able to deliver and release high amounts of iron ions into cells. While high concentrations of iron often trigger ferroptosis, here, the released iron induces pyroptosis, a form of cell death involving the immune system. The iron release occurs only in slightly acidic extracellular environments restricting cell death to cells in acidic microenvironments and allowing for external control. The release mechanism is based on endocytosis facilitated by the lipid-coating followed by degradation of the nanoparticle in the lysosome via cysteine-mediated reduction, which is enhanced in slightly acidic extracellular environment. Thus, a new functionality of hybrid nanoparticles is demonstrated, which uses their nanoarchitecture to facilitate controlled ion delivery into cells. Based on the selectivity for acidic microenvironments, the described nanoparticles may also be used for immunotherapy: the nanoparticles may directly affect the primary tumor and the induced pyroptosis activates the immune system.     

Expanding the structural diversity of polyelectrolyte complexes and polyzwitterions

Charged (macro)molecules are essential components in natural materials and organisms; thus the rational design of biomimetic materials requires a holistic understanding of structure–property relationships in charged systems. We discuss recent progress in uncovering such relationships for polyzwitterions and polyelectrolyte complexes, with emphases on the synthetic strategies that were employed in systematic studies. For polyelectrolytes, discussion is confined to the effects that structural variations in polycation and polyanion structure have on the fundamental phase behavior of the corresponding polyelectrolyte complexes. In the field of polyzwitterions, both fundamental and applied properties are discussed in relation to chemical structure. Finally, we present an overview of promising chemistries that will expand the structural landscape of charged macromolecules with the aim of stimulating new research to further uncover and understand the fundamental design principles for these materials.     

Determination of CFTR densities in erythrocyte plasma membranes using recognition imaging

CFTR (cystic fibrosis transmembrane conductance regulator) is a cAMP-regulated chloride (Cl(-)) channel that plays an important role in salt and fluid movement across epithelia. Cystic fibrosis (CF), the most common genetic disease among Caucasians, is caused by mutations in the gene encoding CFTR. The most predominant mutation, F508del, disturbs CFTR protein trafficking, resulting in a reduced number of CFTR in the plasma membrane. Recent studies indicate that CFTR is not only found in epithelia but also in human erythrocytes. Although considerable attempts have been made to quantify CFTR in cells, conclusions on numbers of CFTR molecules localized in the plasma membrane have been drawn indirectly. AFM has the power to provide the needed information, since both sub-molecular spatial resolution and direct protein recognition via antibody-antigen interaction can be observed. We performed a quantification study of the CFTR copies in erythrocyte membranes at the single molecule level, and compared the difference between healthy donors and CF patients. We detected that the number of CFTR molecules is reduced by 70% in erythrocytes of cystic fibrosis patients.