High-Performance Reversed-Phase Flash Chromatography Purification of Peptides and Chemically Modified Insulins

Preparative reversed-phase HPLC is the established method for the purification of peptides, but has significant limitations. We systematically investigated the use of high-performance reversed-phase flash chromatography (HPFC) to rapidly purify laboratory-scale quantities of crude, synthetic peptides and chemically modified insulins. We demonstrated these methods for a diverse set of peptides, including short, medium, and long peptides. Depending on the purity profile of the peptide, HPFC can be used either as the sole purification method, or as a pre-purification method prior to final HPLC purification. Furthermore, HPFC is suitable for the purification of peptides that are not fully in solution. We provide guidelines for the HPFC of synthetic peptides and small proteins, including the choice of columns, eluents, and gradients. We believe that HPFC is a valuable alternative to HPLC purification of peptides and small proteins.     

Design and validation of a multi-body model of a front suspension bicycle and a passive rider for braking dynamics investigations

The global spread of Electric Bicycles (EBs) is increasing more and more. In addition to supporting the ease of cycling, the electric energy available can also be used for innovative braking control systems. The project BikeSafe picks up on this idea and aims at developing an active Braking Dynamics Assistance system (BDA) for EBs equipped with hydraulic brakes. A simulation model taking into account all substantial braking dynamics influences is necessary for the model-based design of the BDA. This paper presents a Multi-Body Model (MBM) of a front suspension bicycle and a passive rider. This MBM has been experimentally validated for in-plane braking dynamics using road tests. It has real-time ability and can therefore be used as a virtual representation of the plant for the model-based design process of the BDA.     

Bioimaging and Biodistribution of the Metal-Ion-Controlled Self-Assembly of PYY3–36 Studied by SPECT/CT

The controlled self-assembly of peptide- and protein-based pharmaceuticals is of central importance for their mode of action and tuning of their properties. Peptide YY_3–36 (PYY_3–36) is a 36-residue peptide hormone that reduces food intake when peripherally administered. Herein, we describe the synthesis of a PYY_3–36 analogue functionalized with a metal-ion-binding 2,2’-bipyridine ligand that enables self-assembly through metal complexation. Upon addition of Cu^II, the bipyridine-modified PYY_3–36 peptide binds stoichiometric quantities of metal ions in solution and contributes to the organization of higher-order assemblies. In this study, we aimed to explore the size effect of the self-assembly in vivo by using non-invasive quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) imaging. For this purpose, bipyridine-modified PYY_3–36 was radiolabeled with a chelator holding ¹¹¹In^III, followed by the addition of Cu^II to the bipyridine ligand. SPECT/CT imaging and biodistribution studies showed fast renal clearance and accumulation in the kidney cortex. The radiolabeled bipyridyl-PYY_3–36 conjugates with and without Cu^II presented a slightly slower excretion 1 h post injection compared to the unmodified-PYY_3–36, thus demonstrating that higher self-assemblies of the peptide might have an effect on the pharmacokinetics.     

A Bayesian Network approach to the evaluation of building design and its consequences for employee performance and operational costs

A Bayesian Network approach has been developed that can compare different building designs by estimating the effects of the thermal indoor environment on the mental performance of office workers. A part of this network is based on the compilation of subjective thermal sensation data and the associated objective thermal measurements from 12,000 office occupants from different parts of the world. A Performance Index (Π) is introduced that can be used to compare directly the different building designs and furthermore to assess the total economic consequences of the indoor climate with a specific building design. In this paper, focus will be on the effects of temperature on mental performance and not on other indoor climate factors. A total economic comparison of six different building designs, four located in northern Europe and two in Los Angeles, USA, was performed. The results indicate that investments in improved indoor thermal conditions can be justified economically in most cases. The Bayesian Network provides a reliable platform using probabilities for modelling the complexity while estimating the effect of indoor climate factors on human beings, due to the different ways in which humans are affected by the indoor climate.     

Alkali/Chloride release during refuse incineration on a grate: Full-scale experimental findings

Waste to energy (WtE) plants are utilised for the production of heat and electricity. However, due to corrosion at super heater surfaces a relatively low 25% of the waste lower heating value can with the present technology be converted to electricity. High contents of Cl, Na, K, Zn, Pb and S in waste cause relatively high super heater corrosion rates. The Cl-content in waste is one of the key-factors for volatilisation of alkali and heavy metals in WtE plants. Little is known about the release of Cl, Na, K, Zn, Pb, and S along grate of waste incineration plants. The 26 t h^− 1 WtE plant Vestforbrænding unit 5 in Denmark was used for measurements of temperature, gas-concentration (O₂/CO/CO₂), and sampling of gas phase Cl, Na, K, Pb, Zn, and S. Unit 5 has 6 ports distributed along the 13 m long grate between 1.5–1.8 m above the grate. Five of these ports were used for measurements. Two aqueous absorption systems containing a solution of NH₃ or a solution of H₂O₂/HNO₃ were used to collect the gaseous samples. Tar was found to condense in the sampling system at the ports near the fuel inlet. The experiments showed the majority of Cl, Na, and K to be volatilised during the early stages of combustion. The maximum release of Cl, Na, and K was measured in port 2 as 177 ppm_v, 71 ppm_v, and 44 ppm_v respectively. The maximum average gas temperature of 1140 was measured in port 3 compared to the temperatures at ports 2 and 4 of 816 and 551 respectively. It has been suggested to use flue gas from the area of the grate near port 3 with a high temperature, that contains relatively low amounts of corrosive elements, and lead to a separate high temperature super heater and thus increase the electrical efficiency.     

Proteolytic Landscapes in Gastric Pathology and Cancerogenesis

Gastric cancer is a leading cause of cancer-related death, and a large proportion of cases are inseparably linked to infections with the bacterial pathogen and type I carcinogen Helicobacter pylori. The development of gastric cancer follows a cascade of transformative tissue events in an inflammatory environment. Proteases of host origin as well as H. pylori-derived proteases contribute to disease progression at every stage, from chronic gastritis to gastric cancer. In the present article, we discuss the importance of (metallo-)proteases in colonization, epithelial inflammation, and barrier disruption in tissue transformation, deregulation of cell proliferation and cell death, as well as tumor metastasis and neoangiogenesis. Proteases of the matrix metalloproteinase (MMP) and a disintegrin and metalloproteinase domain-containing protein (ADAM) families, caspases, calpain, and the H. pylori proteases HtrA, Hp1012, and Hp0169 cleave substrates including extracellular matrix molecules, chemokines, and cytokines, as well as their cognate receptors, and thus shape the pathogenic microenvironment. This review aims to summarize the current understanding of how proteases contribute to disease progression in the gastric compartment.     

Diels-Alder-Reaktionen. VII. Über die Isomerisierung von 2-Vinylbicyclo[2,2,1]hepten-(5)

Diels-Alder Reactions. VII. The Isomerization of 2-Vinylbicyclo[2,2,1]hept-5-ene The isomerization of exo/endo-2-vinylbicyclo[2,2,1]-hept-5-ene in the presence of Na/Al₂O₃ rapidly gives the thermodynamic equilibrium between exo- and endo-2-vinylbicyclo-[2,2,1]hept-5-ene and cis- and trans-2-ethylidenbicyclo[2,2,1]-hept-5-ene. Far more slowly vinylnortricyclene is formed, which enriches to an equilibrium concentration of about 75% at 60°C. The dependence of equilibrium constants of isomerization on temperature allows the calculation of enthalpies and entropies of isomerization.