Metabolite channeling and compartmentation in the human cell line AGE1.HN determined by 13C labeling experiments and 13C metabolic flux analysis

This study focused on analyzing active pathways and the metabolic flux distribution in human neuronal AGE1.HN cells that is a desirable basis for a rational design and optimization of producing cell lines and production processes for biopharmaceuticals. ¹³C-labeling experiments and ¹³C metabolic flux analysis were conducted using glucose, glutamine, alanine and lactate tracers in parallel experiments. Connections between cytosolic and mitochondrial metabolite pools were verified, e.g., flux from TCA cycle metabolite ¹³C to glycolytic metabolites. It was also found that lactate and alanine are produced from the same pyruvate pool and that consumed alanine is mainly directly metabolized and secreted as lactate. Activity of the pentose phosphate pathway was low being around 2.3% of the glucose uptake flux. This might be compensated in AGE1.HN by high mitochondrial malic enzyme flux producing NADPH. Mitochondrial pyruvate transport was almost zero. Instead pyruvate carbons were channeled via oxaloacetate into the TCA cycle which was mainly fed via α-ketoglutarate and oxaloacetate during the investigated phase. The data indicate that further optimization of this cell line should focus on the improved substrate usage which can be accomplished by an improved connectivity between glycolytic and mitochondrial pyruvate pools or by better control of the substrate uptake.     

Polyamine deactivation of integrated poly(dimethylsiloxane) structures investigated by radionuclide imaging and capillary electrophoresis experiments

The poly(dimethylsiloxane) (PDMS) material provides a number of advantageous features, such as flexibility, elasticity, and transparency, making it useful in integrated analytical systems. Hard fused-silica capillary structures and soft PDMS channels can easily be combined by a tight fit, which offers many alternatives for structure combinations. PDMS and fused silica are in different ways prone to adsorption of low levels of organic compounds. The need for modification of the inner wall surface of PDMS channels may often be necessary, and in this paper, we describe an easy and effective method using the amine-containing polymer PolyE-323 to deactivate both fused-silica and PDMS surfaces. The adsorption of selected peptides to untreated surfaces was compared to PolyE-323-modified surfaces, using both radionuclide imaging and capillary electrophoresis experiments. The polyamine modification displayed a substantially reduced adsorption of three hydrophobic test peptides compared to the native PDMS surface. Filling and storage of aqueous solution were also possible in PolyE-323-modified PDMS channels. In addition, hybrid microstructures of fused silica and PDMS could simultaneously be deactivated in one simple coating procedure.     

Multivalent HSA conjugates of 3'-sialyllactose are potent inhibitors of adenoviral cell attachment and infection

Adenoviruses of serotypes 8, 19 and 37 are the major cause of the severe eye infection EKC (epidemic keratoconjunctivitis). In general, all adenoviruses interact with their cellular receptors through the fibre proteins, which extend from the virus particle. Recently, adenovirus type 37 (Ad37) was found to bind and infect human corneal cells through attachment to carbohydrate structures that carry terminal alpha-(2-3)-linked sialic acids. Herein we present a synthetic route to a 3'-sialyllactose derivative and corresponding multivalent HSA conjugates with varying orders of valency. The potential of these compounds as inhibitors of EKC-causing adenovirus of serotype Ad37, was studied with both a binding assay and an infectivity assay. The results revealed that these compounds effectively prevent Ad37 from binding to and infecting human corneal epithelial (HCE) cells. Moreover, the inhibition is significantly increased with higher orders of multivalency.     

Cryostat for testing luminescence and radiation absorption in ionic crystals

A cryostat is described whose construction makes optical and X-ray examination of crysotals possible within the temperature range 70–500 K. The cryostat is equipped with two quartz glass windows, one metallized mylar window, and a sorption pump which allows an integral vacuum of the order of 10^?3 Pa to be maintained during measurements. A handle allows specimens to be turned by 180° so that an optimum position is obtained in relation to the window.     

A Thermal Neutron Image Intensification System

An image intensifier tube of the vacuum tube type, sensitive to thermal neutrons has been developed and tested. The tube provides a bright visible output signal for an incoming thermal neutron image. Sensitivity, resolution, speed, contrast and relative response to radiation other than thermal neutrons all appear to be adequate for application to neutron imaging studies employing either reactor or non-reactor thermal neutron sources. The above characteristics, and applications of the system, are discussed.     

Pulse electrodeposited cathode catalyst layers for PEM fuel cells

Nanostructured Pt and Pt₃Co cathodes for proton exchange membrane fuel cells (PEMFCs) have been prepared by pulse electrodeposition. For high utilization the catalyst nanoparticles are directly deposited on the microporous layer (MPL) of a commercial available gas diffusion layer (GDL). In order to increase the hydrophilic nature of the substrate surface and thus improve drastically the electrodeposition process and the fuel cell performance, prior to electrodeposition, the carbon substrate is submitted to O₂/Ar plasma activation. Cathodes with different amounts and distributions of Aquivion ionomer within the cathode catalyst layer (CCL) thickness (“homogeneous”, “gradient” and “anti-gradient”), different catalysts (Pt and Pt₃Co) at varied plasma duration and catalyst loading have been prepared. The cathodes are analysed via attenuated total reflection (ATR-IR), goniometer, SEM, 0.5 M H₂SO₄ half-cell and 25 cm² H₂/Air single PEMFC. The highest single fuel cell performance is obtained for 2 min plasma activated Pt₃Co cathode.     

Carbon dioxide adsorption on mesoporous silica surfaces containing amine-like motifs

The postcombustion separation of CO₂ from a flue gas mixture is a unit operation in carbon capture. Today, CO₂ is normally separated with alkanolamines in aqueous solutions. These absorption processes are energy intensive and costly. Increased environmental considerations and the significant footprints of many energy sources warrant the development of new gas separation techniques for the competitive implementation of carbon capture and storage technologies. Improved adsorbent-mediated separation processes are candidates for such new low-energy low-cost processes. In this study, porous silica-based adsorbents with amine-like motifs were synthesized. The temperature- and pressure-dependent adsorption of CO₂ and CO₂/H₂O mixtures were determined and compared for these materials. The experimental uptake capacities of the materials modified with primary propyl amine moieties were significantly higher than those of materials modified with bis-ethanol amine or amidine. The propyl-amine-modified samples also showed good selectivity for CO₂ over nitrogen gas.     

Experimental Study on Phosphorus Partitions Between Liquid Iron and Liquid Slags Based on DRI

Metallurgical and Materials Transactions B - Phosphorus partition between liquid iron and CaO-SiO2-MgO-FeOx slags have been investigated experimentally. Fe doped with Fe3P was equilibrated, at 1873...     

In search of the comfortable indoor environment: A comparison of the utility of objective and subjective indicators of indoor comfort

Today, many procedures for assessing the indoor environment rely on both subjective and objective indicators (e.g. ANSI/ASHRAE 55-2004; ISO 10551). It is however unclear how these two types of measurements are related to perceived comfort. This article aims at assessing the relative utility of subjective (rating scale measures) and objective indicators of perceived comfort of indoor environments. In a hospital setting, physical environmental variables (e.g. temperature, relative humidity and noise level) were simultaneously measured as respondents (both patients and staff) rated their perception of the indoor environment. Regression analyses indicated that the subjective sensory ratings were significantly better than objective indicators at predicting overall rated indoor comfort. These results are discussed in relation to existing measurement procedures and standards.