Bioinformatics Analysis of the Periodicity in Proteins with Coiled-Coil Structure—Enumerating All Decompositions of Sequence Periods

A coiled coil is a structural motif in proteins that consists of at least two α-helices wound around each other. For structural stabilization, these α-helices form interhelical contacts via their amino acid side chains. However, there are restrictions as to the distances along the amino acid sequence at which those contacts occur. As the spatial period of the α-helix is 3.6, the most frequent distances between hydrophobic contacts are 3, 4, and 7. Up to now, the multitude of possible decompositions of α-helices participating in coiled coils at these distances has not been explored systematically. Here, we present an algorithm that computes all non-redundant decompositions of sequence periods of hydrophobic amino acids into distances of 3, 4, and 7. Further, we examine which decompositions can be found in nature by analyzing the available data and taking a closer look at correlations between the properties of the coiled coil and its decomposition. We find that the availability of decompositions allowing for coiled-coil formation without putting too much strain on the α-helix geometry follows an oscillatory pattern in respect of period length. Our algorithm supplies the basis for exploring the possible decompositions of coiled coils of any period length.     

Amine-based nanofibrillated cellulose as adsorbent for CO₂ capture from air

A novel amine-based adsorbent for CO? capture from air was developed, which uses biogenic raw materials and an environmentally benign synthesis route without organic solvents. The adsorbent was synthesized through freeze-drying an aqueous suspension of nanofibrillated cellulose (NFC) and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane (AEAPDMS). At a CO? concentration of 506 ppm in air and a relative humidity of 40% at 25 °C, 1.39 mmol CO?/g was absorbed after 12 h. Stability was examined for over 20 consecutive 2-h-adsorption/1-h-desorption cycles, yielding a cyclic capacity of 0.695 mmol CO?/g.     

Polymer Brush Gradients by Adjusting the Functional Density Through Temperature Gradient

The group of silanes is one of the most abundant classes of molecules used for surface modification. In most studies, silanization is made from the vapor phase or solution. Here, an easy, robust, and fast way not only to modify, but also to map, control, and predict the wetting profiles on silicon surfaces after silanization and the final characteristics of a brush layer polymerized from this silane template profile are presented. The initiator molecule, 2‐bromo‐2‐methyl‐N‐3‐(triethoxysilyl) propyl propanamide (BTPAm), is spin‐casted on a silicon substrate and a thermal gradient is applied using a combinatorial approach for studying the influence of temperature on the spin‐casted silanes. Subsequently, polyacrylamide (PAAm) brushes are grown from the initiating end group of the BTPAm molecules through atom transfer radical polymerization (ATRP). Simulations of the heat distribution inside the silicon wafer allow both confirming the mapping of surface properties and designing desired profiles by predicting thermal distributions. An analytical expression for quantification is also provided. Thus, the wetting properties, surface roughness, and morphology of the brush layer after polymerization are mapped and correlated with the initial BTPAm gradient profile. The studies presented are envisioned to be of interest for designing surface profiles with different wetting properties, facilitating polymer brush growth, and to be used as predictive tools.     

Kinetic Analysis of Crystallization in Li1.3Al0.3Ti1.7(PO4)3 Glass Ceramics

The crystallization mechanisms for Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) glass ceramics were studied using thermophysical property characterization techniques. Differential scanning calorimetry (DSC) revealed two separate exothermic events that were ascribed to the initial growth and growth to coherency of a dendritic phase. It was found that the commonly used Johnson‐Mehl‐Avrami is not a suitable kinetic model for this material. Rather, the Sestak‐Berggren (SB) autocatalytic kinetic model was used to analyze the DSC data and the activation energy for initial growth (259 kJ/mol) and coherency (272 kJ/mol) was calculated using isoconversional methods. The calculated parameters for the SB model were used to compare experimental and calculated values for heat flow during the crystallization of LATP and good fits were found for both exothermic events.     

First plasma operation of the enhanced JET vertical stabilisation system

A project dedicated to the enhancement of the JET vertical stabilization system was launched in 2006, including an upgrade of the Power Supply of the Radial Field Amplifier, of hardware and software of the vertical stabilization control system. The main aim was to double the JET capability in stabilising high current plasmas when subject to perturbations, in particular large Edge Localised Modes. We present here the results of first plasma operation with the new Enhanced Radial Field Amplifier and its data acquisition and control system, focussing on the benefits of an approach based on phased commissioning, modelling and offline algorithm validation.     

Steam gasification of co-pyrolysis chars from various types of biomass

Co-pyrolysis of two different types of biomass among apple tree branch (ATB), knotweed stem (KWS), seaweed (SW) and rice straw (RSt) was conducted to obtain co-pyrolysis char (co-char), and then the steam gasification of those co-chars was compared with the steam co-gasification of the physically mixed individual biochars to investigate the synergetic effect resulted from alkali and alkali earth metal (AAEM) in each biomass involved. It is found that the silica species in the RSt had negative effect on the activity of co-char due to the formation of alkali silicate compounds. However, combination of RSt with some non-woody biomass such as SW also showed promoting effect. In particular, the gasification of the co-char from the combination of various biomass with low or no silica content showed improved gasification efficiencies due to the synergetic effect AAEM species in the co-char from the different biomass. Therefore, the biomass selection should play a significant role in the co-pyrolysis of different biomass in the two-stage gasification system.     

Alkaline hydrogels as ion-conducting coupling material for electrochemical chloride extraction

One method to rehabilitate chloride-contaminated reinforced concrete structures is electrochemical chloride extraction, by which chloride ions are extracted from the pore system of the concrete using an externally applied voltage. Although many factors influence the efficacy of electrochemical chloride extraction, a number of these, such as the concrete cover and the chloride profile, are predefined by the structure. One factor with major influence that can be improved is the coupling material. In this contribution, we present a suitable coupling material in the form of a highly alkaline hydrogel, with which the applied voltage can be reduced from 40–50 to 1 V under laboratory conditions. The reduction is due to the high conductivity of the gel and its excellent electrolytic contact with concrete. In a field test on chloride-infested car-park columns, more than 95% of the chloride could be extracted with 2–3 cycles, each comprising of 21 days of extraction and 7 days of rest. During the entire treatement, the gel did not require any attending to, such as replacing evaporated moisture.     

Feasibility of intravoxel incoherent motion in the assessment of tumor microvasculature and blood–brain barrier integrity: a case-based evaluation of gliomas

Magnetic Resonance Materials in Physics, Biology and Medicine - To evaluate the feasibility of intravoxel incoherent motion (IVIM) in assessing blood–brain barrier (BBB) integrity and...