Helix Coils Research Articles

Expression, cloning, and IgE-binding of the full-length dust mite allergen Der f 8.

Dermatophagoides farinae, a domestic mite species, produces some of the most potent allergens that contribute to allergy in China and worldwide. We sought to clone and express the group 8 allergen of D. farinae (Der f 8) to investigate its IgE-binding reactivity. The full-length cDNA encoding Der f 8 was generated by using RT-PCR and 5' RACE, cloned into pCold-TF expression vector, confirmed by nucleotide sequencing, sub-cloned into pET-28b (+), and transfected into E. coli BL21 cells for expression. After purification by nickel affinity chromatography and identified by SDS-PAGE, the recombinant Der f 8 bound with sera from 40.9% (9/22) of mite-allergic patients according to ELISA testing. Analysis of the recombinant DNA sequence revealed a 231 amino acid open reading frame encoding a protein with a derived molecular mass of 26.4kDa and an isoelectric point of 6.84. The deduced amino acid sequence has nine phosphorylation sites, displaying strong homology with glutathione S-transferase, and its secondary structure comprises alpha helix (45.5%), extended strand (11.3%), and random coils (43.3%). BLAST through the National Center for Biotechnology Information database and alignment identified similarity with group 8 allergens or glutathione S-transferases of Dermatophagoides pteronyssinus, Suidasia medanensis, Lepidoglyphus destructor, Glycyphagus domesticus, and Aleuroglyphus ovatus (64, 65, 53, 53, and 50%, respectively). The first recombinant Der f 8 protein produced in full length successfully bound with patient IgE, demonstrating the importance of Der f 8 in mite allergy.

Magnet Design and Analysis of a 40 Tesla Long Pulse System Energized by a Battery Bank

A 40 tesla long pulse magnet and a battery bank as the power supply have been designed. This is now under construction at the Wuhan National High Magnetic Field Center. The 22 mm bore magnet will generate smooth pulses with duration 1 s and rise time 0.5 s. The battery bank consists of 945 12V/200 Ah lead-acid battery cells. The magnet and battery bank were optimized by codes developed in-house and by ANSYS. The coil was made from soft copper with internal reinforcement by fiber-epoxy composite; it is divided into two sections connected in series. The inner section consists of helix coils with each layer reinforced by Zylon composite. The outer section will be wound from copper sheet and externally reinforced by carbon fiber composite.

Magnetic Microhelix Coil Structures

Together with the well-known ferro- and antiferromagnetic ordering, nature has created a variety of complex helical magnetic configurations. Here, we design and investigate three-dimensional microhelix coil structures that are radial-, corkscrew-, and hollow-bar-magnetized. The magnetization configurations of the differently magnetized coils are experimentally revealed by probing their specific dynamic response to an external magnetic field. Helix coils offer an opportunity to realize microscale geometries of the magnetic toroidal moment, observed so far only in bulk multiferroic materials.

Morphology and growth mechanism of single-helix spring-like carbon nanocoils with laces prepared using Ni/molecular sieve (Fe) catalyst

Single-helix spring-like carbon coils with laces grew over the Ni metal catalyst supported on molecular sieve containing a trace amount of an Fe impurity that originated from a kaolin clay raw material. The morphology, microstructure, and growth mechanism of the single-helix carbon nanocoils and laces were investigated. We found that a trace amount of Fe impurity contained in the molecular sieve was a key factor in the lace growth. It is considered that the Fe impurity may poison, restraint the formation of three crystal faces, resulting in the growth of single helix coils. It is also considered that a very strong inner stress is periodically formed between the boundary of two fibers, and the thin carbon film is swelled to form laces.

Theoretical study of volume changes associated with the helix–coil transition of an alanine‐rich peptide in aqueous solution

The changes in the partial molar volume (PMV) associated with the conformational transition of an alanine-rich peptide AK16 from the alpha-helix structure to various random coil structures are calculated by the three-dimensional interaction site model (3D-RISM) theory coupled with the Kirkwood-Buff theory. The volume change is analyzed by decomposing it into contributions from geometry and hydration: the changes in the van der Waals, void, thermal, and interaction volume. The total change in the PMV is positive. This is primarily due to the growth of void space within the peptide, which is canceled in part by the volume reduction resulting from the increase in the electrostatic interaction between the peptide and water molecules. The changes in the void and thermal volume of the coil structures are widely distributed and tend to compensate each other. Additionally, the relations between the hydration volume components and the surface properties are investigated. We categorize coil structures into extended coils with the PMV smaller than helix and general coils with the PMV larger than helix. The pressure therefore can both stabilize and destabilize the coil structures. The latter seems to be a more proper model of random coil structures of the peptide.

Vapor Phase Growth of Carbon Microcoils / Nanocoils

The carbon microcoils and carbon nanocoils were prepared by the catalytic pyrolysis of acetylene under the Ni and/or Fe-containing catalysts, and the growth pattern, morphology and growth mechanism of the carbon coils were examined in detail. The inner coil diameter of carbon microcoils are of several µm and coil gap from zero to several µm. The inner coil diameter of carbon nanocoils are from zero to several ten nm and coil gap from zero to several nm. The carbon microcoils are generally of double helix coils such as DNA while carbon nanocoils were single helix coils such as α-helix proteins, with spring-like or twisted forms. A catalyst grain was usually observed on the tip of carbon coil. The carbon nanocoils are almost amorphous and can be graphitized by the high temperature heat-treatment.

Morphologies of carbon micro-coils grown by chemical vapor deposition

The carbon micro-coils were obtained by the Ni-catalyzed pyrolysis of acetylene. The carbon micro-coils with various coiling morphology: regular double coils, coils built up by circular or flat fibers, super helix coils, single coils, etc. can be observed. The carbon coils with various coil diameters and coil pitches were obtained by controlling reaction conditions, such as reaction temperature, source gas flow rate of sulfur-impurity, acetylene or hydrogen.

Strong and ultrastrong pulsed magnetic fields

Methods for generating pulsed magnetic fields are discussed with a view to applications in experimental physics. “Ultrastrong” fields above 100 T (= 1 MG) are characterized by inevitable coil destruction. The following methods are reviewed: compact multilayer coils (max. 50 T, 1 ms–1 s), solid helix coils (50–100 T, ≈100 μs), lightweight single turn coils (1–3 MG, 2 μs), electromagnetic implosion (1–3 MG, < <1 μs), explosive-driven generators (up to 2 MG, 1–5 μs, large volume) and explosive-driven implosions (1–10 MG, <1 μs). The interaction of pulsed fields with electrical conductors is discussed with a view to the ultimate limits of coil structures and the heating of conducting samples.

Radar cross section of a small low-pitch angle helix

A method of calculating the radar cross section of a dipole deformed into a helix of low-pitch angle is briefly discussed. Theoretical backscatter results are presented that show how the cross section varies as the helix coils into several turns. An interesting property of the current distribution is also discussed.