Function of IRAG2 Is Modulated by NO/cGMP in Murine Platelets

Inositol 1,4,5-triphosphate receptor-associated 2 (IRAG2) is a type II membrane protein located at the endoplasmic reticulum. It is a homologue of inositol 1,4,5-triphosphate receptor-associated cGMP kinase substrate 1 (IRAG1), a substrate protein of cGMP-dependent protein kinase I (PKGI), and is among others expressed in platelets. Here, we studied if IRAG2 is also located in platelets and might be a substrate protein of PKGI. IRAG2 was detected in platelets of IRAG2-WT animals but not in those of IRAG2-KO animals. Next, we validated by co-immunoprecipitation studies that IRAG2 is associated with IP₃R1-3. No direct stable interaction with PKGIβ or with IRAG1 was observed. Phosphorylation of IRAG2 in murine platelets using a Ser/Thr-specific phospho-antibody was found in vitro and ex vivo upon cGMP stimulation. To gain insight into the function of IRAG2, platelet aggregation studies were performed using thrombin and collagen as agonists for treatment of isolated IRAG2-WT or IRAG2-KO platelets. Interestingly, platelet aggregation was reduced in the absence of IRAG2. Pretreatment of wild type or IRAG2-KO platelets with sodium nitroprusside (SNP) or 8-pCPT-cGMP revealed a further reduction in platelet aggregation in the absence of IRAG2. These results show that IRAG2 is a substrate of PKGI in murine platelets. Furthermore, our results indicate that IRAG2 is involved in the induction of thrombin- or collagen-induced platelet aggregation and that this effect is enhanced by cGMP-dependent phosphorylation of IRAG2. As IRAG1 was previously shown to inhibit platelet aggregation in a cGMP-dependent manner, it can be speculated that IRAG2 exerts an opposing function and might be an IRAG1 counterpart in murine platelets.     

Port reduction in parametrized component static condensation: approximation and a posteriori error estimation

We introduce a port (interface) approximation and a posteriori error bound framework for a general component‐based static condensation method in the context of parameter‐dependent linear elliptic partial differential equations. The key ingredients are as follows: (i) efficient empirical port approximation spaces—the dimensions of these spaces may be chosen small to reduce the computational cost associated with formation and solution of the static condensation system; and (ii) a computationally tractable a posteriori error bound realized through a non‐conforming approximation and associated conditioner—the error in the global system approximation, or in a scalar output quantity, may be bounded relatively sharply with respect to the underlying finite element discretization. Our approximation and a posteriori error bound framework is of particular computational relevance for the static condensation reduced basis element (SCRBE) method. We provide several numerical examples within the SCRBE context, which serve to demonstrate the convergence rate of our port approximation procedure as well as the efficacy of our port reduction error bounds. Copyright © 2013 John Wiley & Sons, Ltd.     

Robust manufacturing inspection and classification with machine vision

This paper presents and compares methods for inspecting products using machine vision systems. This research compares the Mahalanobis Taguchi System (MTS) with a method based on principal component transformation and multi-modal overlap methods, and which is called the Principal component Feature overlap Measure (PFM). In an example application, the PFM achieves significantly higher Signal/Noise-ratios (+80 dB) and equal or better classification performance than MTS with a lower number of classification features (-75%).     

Investigation on PEM water electrolysis cell design and components for a HyCon solar hydrogen generator

Hydrogen as a secondary energy carrier promises a large potential as a long term storage for fluctuating renewable energies. In this sense a highly efficient solar hydrogen generation is of great interest especially in southern countries having high solar irradiation. The patented Hydrogen Concentrator (HyCon) concept yields high efficiencies combining multi-junction solar cells with proton exchange (PEM) membrane water electrolysis. In this work, a special PEM electrolysis cell for the HyCon concept was developed and investigated. It is shown that the purpose-made PEM cell shows a high performance using a titanium hybrid fiber sinter function both as a porous transport layer and flow field. The electrolysis cell shows a high performance with 1.83 V at 1 A/cm² and 24 °C working under natural convection with a commercially available catalyst coated membrane. A theoretical examination predicts a total efficiency for the HyCon module from sunlight to hydrogen of approximately 19.5% according to the higher heating value.     

Porous concrete as a template for the synthesis of porous carbon materials

The potential of industrial porous concrete for using as a template for the synthesis of porous carbon materials has been investigated. Carbon replicas of porous concrete have been prepared by carbonization of sucrose. The pores of the resulting carbon materials range from the macropore to the micropore region, pointing to a hierarchy.     

Potenzial von freien Flankenmodifikationen für Beveloidverzahnungen

In recent years the beveloid gear, also known as conical involute gear, is shifting more and more into the spotlight. The beveloid gear has been an important part of marine transmissions for years and is nowadays used to transmit the torque of the output shaft of the gearbox onto the front axle in a four wheel drive vehicle. The small need of design space and the reduced amount of design parts necessary in comparison to conventional transfer gearboxes, distinguish the beveloid gear. The conjugate flank of beveloid gears promises the best operational behavior. However because of its geometry the conjugate flank cannot be manufactured with standard manufacturing processes. Standard modification such as crowning offer a possibility to enhance the operational behavior of involute beveloid gears but cannot reach the whole potential given by conjugated beveloid gears. Therefore, the objective of the following report is to investigate the potential of free flank modifications of beveloid gears regarding the operational behavior. After a brief overview on existing geometry optimization methods for beveloid gears, the method for free flank modifications by means of a weighted objective function is defined and applied to an example gear. The results of the investigation show that free flank modifications offer a high level of improvement of the operational behavior. The comparison with a non-modified gear, a gear with standard modifications and a gear with free flank modifications for three different load steps proves that free flank modifications offer a higher durability and lower noise excitation.