Copolymerization Behavior of Acid‐Base Monomer Systems and Properties of their Corresponding Polymers

The copolymerization behavior of mixtures of an acidic and a basic monomer were studied as a function of the monomer feed composition. The four systems investigated in this way comprised APSA/1‐VIm, APSA/4‐VP, APSA/DAMA, and SSA/1‐VIm. The corresponding polyelectrolytes were obtained by free radical polymerization of the monomer mixtures in solution, while the isolated monomeric salts of equivalent amounts of both monomers were prone to spontaneous polymerization. For APSA/1‐VIm, APSA/4‐VP, and APSA/DAMA, a donor‐acceptor relationship was found, whereas for SSA/1‐VIm the SSA was favorably incorporated over all feed ratios. High T_g and complex viscosity data indicated a considerable degree of ionic, thermally reversible crosslinking within the polymers that were thermally stable up to at least 230 °C.

     

Rotaxane Assemblies with Dendritic Architecture

Strategies towards the synthesis of well‐defined, mechanically interlocked, dendritic assemblies of rotaxanes are developed, one using a divergent, and the other a convergent approach. For the first time covalent bonds are not directly involved in the branching of dendrimers, only mechanical bonds act as unique branching elements.     

Incidental learning of S-R contingencies in the masked prime task.

Subliminal motor priming effects in the masked prime paradigm can only be obtained when primes are part of the task set. In 2 experiments, the authors investigated whether the relevant task set feature needs to be explicitly instructed or could be extracted automatically in an incidental learning paradigm. Primes and targets were symmetrical arrows, with target color, not shape, the response-relevant feature. Shape and color covaried for targets (e.g., always blue, >     

Development of a Raman method to follow the evolution of coating thickness of pellets

Context: Although several methods have been investigated to measure the film thickness of tablets and its correlation with the dissolution behavior, much fewer such investigations exist for pharmaceutical pellets.

Objective: To study the possibility of measuring the film thickness and predicting the dissolution behavior of pellets produced in different fluid bed equipments with Raman spectroscopy.

Materials and methods: Pyridoxine hydrochloride-layered pellets were produced and coated in two different Strea-1 equipments. Raman spectra were collected and analysed to set up a calibration model based on the film thickness data calculated from Camsizer analysis results. Dissolution tests were done according to Ph. Eur. standards.

Results: Raman spectroscopy proved to be a good tool in the measurement of film thickness. Polymer weight gain showed a linear correlation with film thickness but was a poor predictor of dissolution results below a threshold value.

Conclusion: The Raman spectroscopic measurement of a small sample can provide accurate data of the film thickness. The investigation suggests that a threshold value might exist for the film thickness above which it can be used to judge future dissolution results.     

A new notion of part structure for natural language

In this paper a new notion of part structure for the semantics of natural language is presented: a notion of part structure that is relative to a situation and unlike extensional mereological notions, crucially involves conditions of integrity. The notion is motivated by a variety of different constructions of natural language.     

n-Butane Isomerization Catalyzed by Sulfated Zirconia Nanocrystals Supported on Silica or γ-Alumina

Supported sulfated zirconia catalysts with zirconia contents of 10, 20 and 50 wt% were prepared by impregnation of SiO₂ and γ-Al₂O₃ supports with H₂SO₄/ Zr(SO₄)₂ solutions followed by calcination at 923 K. The catalysts were characterized by X-ray diffraction, extended X-ray absorption fine structure measurements, thermal analysis, UV–vis spectroscopy, and electron microscopy. Tetragonal zirconia was detected in all silica-supported samples but only in the 50 wt% zirconia-containing alumina-supported sample, indicating high dispersion of zirconia on alumina. Alumina-supported samples retained additional sulfate, at least in part as Al₂(SO₄)₃. All samples were active in n-butane isomerization (1 kPa n-butane, 378 K). There was no relation between the presence of tetragonal zirconia in these samples and the catalytic performance.     

Superporous Poly(ethylene glycol) Diacrylate Cryogel with a Defined Elastic Modulus for Prostate Cancer Cell Research

The physical and mechanical properties of the tumor microenvironment are crucial for the growth, differentiation and migration of cancer cells. However, such microenvironment is not found in the geometric constraints of 2D cell culture systems used in many cancer studies. Prostate cancer research, in particular, suffers from the lack of suitable in vitro models. Here a 3D superporous scaffold is described with thick pore walls in a mechanically stable and robust architecture to support prostate tumor growth. This scaffold is generated from the cryogelation of poly(ethylene glycol) diacrylate to produce a defined elastic modulus for prostate tumor growth. Lymph node carcinoma of the prostate (LNCaP) cells show a linear growth over 21 d as multicellular tumor spheroids in such a scaffold with points of attachments to the walls of the scaffold. These LNCaP cells respond to the growth promoting effects of androgens and demonstrate a characteristic cytoplasmic‐nuclear translocation of the androgen receptor and androgen‐dependent gene expression. Compared to 2D cell culture, the expression or androgen response of prostate cancer specific genes is greatly enhanced in the LNCaP cells in this system. This scaffold is therefore a powerful tool for prostate cancer studies with unique advantages over 2D cell culture systems.     

Frame Complexity and the Financial Crisis: A Comparison of the United States,the United Kingdom,and Germany in the Period 2007–2012

Communicative complexity concerns the variety of issues and stakeholders (agenda complexity) and their associations (frame complexity) in the news. One issue may dominate news in crises (9/11, Katrina), but as soon as complexity recovers, uncertainty may decrease and the public mood may improve. The financial crisis in the United States, the United Kingdom, and Germany (2007–2012) offers an example. An automated content analysis was applied to over 160,000 newspaper articles. Frame complexity decreased until the spotlight fell on the demise of Bear Stearns and Lehman Brothers (2008). The subsequent gradual recovery was only partly interrupted by the euro crisis. A Vector AutoRegression time series analysis shows that increasing frame complexity may indeed have fostered the recovery of financial markets and consumer confidence.