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A new [Cu2bix2] sub-ring modifying Wells–Dawson polyoxometalates (POMs) compound containing, H10[Cu(bix)2(P2W18O62)2](bix)6·16H2O (CubixP2W18) (bix = 1,4-bis(imidazol-1-ylmethyl)benzene), has been synthesized, characterized and studied as electrochemical biosensor for detecting uric acid (UA) for the first time in the work. Interesting is that CubixP2W18 contain fascinating left- and right-helical chain. Moreover, the CubixP2W18 modified glassy carbon electrodes (GCE) shows excellent electrochemical activities and higher selectivity and stabilization toward UA. The linear response range is from 2.5 × 10−7 M to 6.79 × 10−4 M and the lower detection limit is as low as 4.97 × 10−7 M (S/N = 3). The strategy of employing Wells–Dawson POMs-based sensors provides a new pathway to design new sensor for detecting UA in the field of sensor and medical diagnosis. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we investigate the representation of curves on the lightlike cone Q 2 3 $\mathbb {Q}^{3}_{2}$ in Minkowski space R 2 4 $\mathbb {R}^{4}_{2}$ by structure functions. In addition, with this representation, we classify all of the null curves on the lightlike cone Q 2 3 $\mathbb {Q}^{3}_{2}$ in four types, and we obtain a natural Frenet frame for these null curves. Furthermore, for this natural Frenet frame, we calculate curvature functions of a null curve, especially the curvature function κ 2 = 0 $\kappa _{2}=0$ , and we show that any null curve on the lightlike cone is a helix. Finally, we find all curves with constant curvature functions.

Null cartan curves have been studied by some geometers in both Euclidean and Minkowski spaces, but some special characters of the curves are not considered. In this paper, we study weak AW (k) – type and AW (k) – type null cartan curve in Minkowski 3-space E13E_1^3 . We define helix according to Bishop frame in E13E_1^3 . Furthermore, the necessary and sufficient conditions for the helices in Minkowski 3-space are obtained.

Identical hard spheres in cylindrical confinement exhibit a rich variety of densest-packed columnar structures. Such structures, which generally vary with the corresponding cylinder-to-sphere diameter ratio D, serve as structural models for a variety of experimental systems at the micro- or nano-scale. In this research, the electrical conductivity as a function of D has been studied for four different types of such columnar structures. It was found that, for increasing D, the electrical conductivity of each type of structures decreases monotonously, as a result of the system’s resistive components becoming more densely packed along the long axis of the cylindrical space. However, there exists a discontinuous rise in the system’s electrical conductivity at D=1+3/2 (discontinuous zigzag-to-single-helix transition) and D = 2 (discontinuous double-helix-to-double-helix transition), respectively, as a result of the establishment of additional conducting paths upon an abrupt increase in the number of inter-particle contacts. This is not the case for the continuous single-helix-to-double-helix transition at D=1+43/7. The results, which tell us how the system’s electrical conductivity can be tuned through a variation of D, could serve as a guide for the development of quasi-one-dimensional materials with a structurally tunable electrical conductivity.

In nature, chirality transfer refines biomolecules across all size scales, bestowing them with a myriad of sophisticated functions. Despite recent advances in replicating chirality transfer with biotic or abiotic building blocks, a molecular understanding of the underlying mechanism of chirality transfer remains a daunting challenge. In this paper, the coassembly of two types of glycopeptide molecules differing in capability of forming intermolecular hydrogen bonds enabled the involvement of discontinuous hydrogen bond, which allowed for a nanoscale chirality transfer from glycopeptide molecules to chiral micelles, yet inhibited the micrometer scale chirality transfer toward helix formation, leading to an achiral transfer from chiral micelles to planar monolayer. Upon stacking the monolayer into a bilayer, the nonsuperimposable front and back faces of the chiral micelles involved in the monolayer ribbons lead to the opposite rotation of two layers toward increasing the continuity of H-bonds. The resultant continuity triggered the symmetry breaking of stacked bilayers and thus reactivated the micrometer-scale chirality transfer toward the final helix. This work delineates a promising step toward a better understanding and replicating the naturally occurring chirality transfer events and will be instructive to future chiral material design.

DNA is an ideal template for the design of nanoarchitectures with molecular-like features. Here, we present an optimized assembly strategy for the concatenation of DNA quasi-rings into long scaffolds. Ionic strength, which played a major role during self-assembly, produced the expected high quality only at 15 mM MgCl 2 . Atomic force microscopy (AFM) characterization showed several micrometer long tubular structures that were used as templates for the positioning of plasmonic nanoparticles (NPs) along a three-dimensional helical path using DNA tethers. As imaged by high-resolution scanning transmission electron microscopy (HR-STEM) and modeled by theoretical calculations, the NPs distributed into a "fusilli" fashion (i.e., a helical pasta shape), displaying chiroptical activity as revealed by a bisignated CD absorption, centered at the plasmon resonance wavelength. The present structures contribute to enrich the ever-developing arena of chiroplasmonic DNA-based nanomaterials and demonstrate that large assemblies are attainable for their future application to develop metamaterials.

Chirality is ubiquitous in nature with primary cellular functions that include construction of right‐/left‐handed helix and selective communications among diverse biomolecules. Of particularly intriguing are the chiral peptide‐based materials that can be deliberately designed to change physicochemistry properties via tuning peptide sequences. Critically, understanding their chiral effects are fundamental for the development of novel materials in chemistry and biomedicine fields. Here, we review recent researches on chirality in peptide‐based materials, summarizing relevant typical chiral effects towards recognition, amplification, and induction. Driven forces for the chiral discrimination in affinity interaction as well as the handedness preferences in supramolecular structure formation at both the macroscale and microscale are illustrated. The implementation of such chirality effects of artificial copolymers, assembled aggregates and their composites in the fields of bioseparation and bioenrichment, cell incubation, protein aggregation inhibitors, chiral smart gels, and bionic electro devices are also presented. At last, the challenges in these areas and possible directions are pointed out. The diversity of chiral roles in the origin of life and chirality design in different organic or composite systems as well as their applications in drug development and chirality detection in environmental protection are discussed. [ABSTRACT FROM AUTHOR]

Discrete and structurally diverse foldamer sequences are constructed in both natural and abiotic systems primarily using inert connectivity with irreversible organic covalent bonds, serving to preserve the identity of the sequence. The formation of sequences under thermodynamic control using labile coordination bonds would be attractive for synthetic ease and modular capability, but this presents issues regarding sequence preservation. Here is presented an approach integrating palladium(II) metal ions into the sequence itself, with fidelity maintained through use of complementary pairings of ligand arrangements at the metal centre. This is accomplished using sites of different denticity and/or hydrogen bonding capability. In this fashion, discrete and ordered metallo‐sequences are formed as thermodynamic products in a single step, and these then fold into defined conformations due to π–π interactions between electron‐rich and ‐poor aromatic regions of the combined componentry. [ABSTRACT FROM AUTHOR]

Discrete and structurally diverse foldamer sequences are constructed in both natural and abiotic systems primarily using inert connectivity with irreversible organic covalent bonds, serving to preserve the identity of the sequence. The formation of sequences under thermodynamic control using labile coordination bonds would be attractive for synthetic ease and modular capability, but this presents issues regarding sequence preservation. Here is presented an approach integrating palladium(II) metal ions into the sequence itself, with fidelity maintained through use of complementary pairings of ligand arrangements at the metal centre. This is accomplished using sites of different denticity and/or hydrogen bonding capability. In this fashion, discrete and ordered metallo‐sequences are formed as thermodynamic products in a single step, and these then fold into defined conformations due to π–π interactions between electron‐rich and ‐poor aromatic regions of the combined componentry. [ABSTRACT FROM AUTHOR]

Helices can be found in the art and architecture of many periods, but almost always as single elements. They can be combined to make infinite structures that provide a range of possibilities for sculpture that have been little explored. The most symmetrical arrangements of helices in three dimensions can be derived from the known ways of packing rods. Some of these possibilities suggest new forms that have helices that pass through the vertices of polyhedra, and, because of the symmetry, there can be a possibility other than the standard construction of a helix through four points. One of the infinite structures is the basis for a newly described enantiomorphic saddle polyhedron that can fill space with its mirror image. [ABSTRACT FROM AUTHOR]

Spiroplasma are helical bacteria that lack a peptidoglycan layer. They are widespread globally as parasites of arthropods and plants. Their infectious processes and survival are most likely supported by their unique swimming system, which is unrelated to well-known bacterial motility systems such as flagella and pili. Spiroplasma swims by switching the left- and right-handed helical cell body alternately from the cell front. The kinks generated by the helicity shift travel down along the cell axis and rotate the cell body posterior to the kink position like a screw, pushing the water backward and propelling the cell body forward. An internal structure called the "ribbon" has been focused to elucidate the mechanisms for the cell helicity formation and swimming. The ribbon is composed of Spiroplasma -specific fibril protein and a bacterial actin, MreB. Here, we propose a model for helicity-switching swimming focusing on the ribbon, in which MreBs generate a force like a bimetallic strip based on ATP energy and switch the handedness of helical fibril filaments. Cooperative changes of these filaments cause helicity to shift down the cell axis. Interestingly, unlike other motility systems, the fibril protein and Spiroplasma MreBs can be traced back to their ancestors. The fibril protein has evolved from methylthioadenosine/S-adenosylhomocysteine (MTA/SAH) nucleosidase, which is essential for growth, and MreBs, which function as a scaffold for peptidoglycan synthesis in walled bacteria. [ABSTRACT FROM AUTHOR]

The very stable helices of 8‐amino‐2‐quinolinecarboxylic acid oligoamides are shown to uptake CuII ions in their cavity through deprotonation of their amide functions with minimal alteration of their shape, unlike most metallo‐organic structures which generally differ from their organic precursors. The outcome is the formation of intramolecular linear arrays of a defined number of CuII centers (up to sixteen in this study) at a 3 Å distance, forming a molecular mimic of a metal wire completely surrounded by an organic sheath. The helices pack in the solid state so that the arrays of CuII extend intermolecularly. Conductive‐AFM and cyclic voltammetry suggest that electrons are transported throughout the metal‐loaded helices in contrast with hole transport observed for analogous foldamers devoid of metal ions. [ABSTRACT FROM AUTHOR]

N‐terminal thiourea‐modified l‐Leu‐based peptide {(3,5‐diCF3Ph)NHC(=S)‐(l‐Leu‐l‐Leu‐Ac5c)2‐OMe} with five‐membered ring α,α‐disubstituted α‐amino acids (Ac5c) catalyzed a highly enantioselective 1,4‐addition reaction between β‐nitrostyrene and dimethyl malonate. The enantioselective reaction required only 0.5 mol % chiral peptide‐catalyst in the presence of iPr2EtN (2.5 equiv.), and gave a 1,4‐adduct with 93 % ee of an 85 % yield. As Michael acceptors, various β‐nitrostyrene derivatives such as methyl, p‐fluoro, p‐bromo, and p‐methoxy substituents on the phenyl group, 2‐furyl, 2‐thiophenyl, and naphthyl β‐nitroethylenes could be applied. Furthermore, various alkyl malonates and cyclic β‐keto‐esters could be used as Michael donors. It became clear that the length of the peptide chain, a right‐handed helical structure, amide N−Hs, and the N‐terminal thiourea moiety play crucial roles in asymmetric induction. [ABSTRACT FROM AUTHOR]

Chiroptical polythiophene (PTh), as one of the most important chiral conductive polymers, is an emerging and hot topic in chiral materials, which shows great application potentials in fields as diverse as chiral sensing and separation, asymmetry catalysis, chiroptoelectronics, and even chiro‐spintronics. This review summarizes progress in chiral polythiophenes (PThs) in the past 10 years, including the synthesis, properties and applications. Main focus is placed on the manner in which chirality is implemented and the optical activity of the chiral PThs. We showcase examples in which the chirality of PThs is induced by side chain substituents with point, planar, and axial chirality or arises from external chiral media. Application of chiral PThs is also included. Finally, perspectives for further development are offered. [ABSTRACT FROM AUTHOR]

The purpose of this application, under Article 23.9.5 of the Code, is to conserve the specific name Helix plicaria Lamarck, 1816, a junior primary homonym of Helix plicariaBorn, 1778. These names are currently in use for two different groups of land and freshwater snails, respectively, and have not been treated as congeneric since 1828. Helix plicariaBorn, 1778 was first transferred to the genus BulimusScopoli, 1777 and subsequently to the genera ThiaraRöding, 1798, MelaniaLamarck, 1799, MelanoidesOlivier, 1804 and StenomelaniaFischer, 1885. Helix plicariaLamarck, 1816 has either been treated as belonging to HelixLinnaeus, 1758, CochleaDa Costa, 1778 or has been included in HemicyclaSwainson, 1840. It is proposed that Helix plicariaLamarck, 1816 be conserved by ruling it is not invalid by reason of being a junior homonym of Helix plicariaBorn, 1778. [ABSTRACT FROM AUTHOR]

Spiroplasma are helical bacteria that lack a peptidoglycan layer. They are widespread globally as parasites of arthropods and plants. Their infectious processes and survival are most likely supported by their unique swimming system, which is unrelated to well-known bacterial motility systems such as flagella and pili. Spiroplasma swims by switching the left- and right-handed helical cell body alternately from the cell front. The kinks generated by the helicity shift travel down along the cell axis and rotate the cell body posterior to the kink position like a screw, pushing the water backward and propelling the cell body forward. An internal structure called the “ribbon” has been focused to elucidate the mechanisms for the cell helicity formation and swimming. The ribbon is composed of Spiroplasma-specific fibril protein and a bacterial actin, MreB. Here, we propose a model for helicity-switching swimming focusing on the ribbon, in which MreBs generate a force like a bimetallic strip based on ATP energy and switch the handedness of helical fibril filaments. Cooperative changes of these filaments cause helicity to shift down the cell axis. Interestingly, unlike other motility systems, the fibril protein and Spiroplasma MreBs can be traced back to their ancestors. The fibril protein has evolved from methylthioadenosine/S-adenosylhomocysteine (MTA/SAH) nucleosidase, which is essential for growth, and MreBs, which function as a scaffold for peptidoglycan synthesis in walled bacteria.

Controlling the structural transition between well‐defined architectures found in living system is essential in polymer chemistry as well as material science. Herein, the reversible conformational switch of a non‐natural polypeptide with an aromatic ring (2,6‐naphthalene spacer) on its peptide backbone, referred to as an arylopeptide, between two distinct well‐defined helical structures (extended 31‐helix and contracted 41‐helix) using side chain solvation is demonstrated. The folding selectivity of the arylopeptide and found that the affinity between the solvent and side chains is an essential factor for determining the global structure is investigated. A thermoresponsive arylopeptide bearing oligoether groups (─(CH2CH2O)9CH3)) on the side chain is designed, which exhibited unique lower critical solution temperature behavior and converted from the 31 to the 41‐helix depending on the temperature. Furthermore, the solvent affinity of the entire polymer by combining substituents (─(CH2CH2O)3CH3 and ─C12H25) with different properties on the side chains to achieve a spring‐like expansion–contraction system that allows interconversion between 31‐ and 41‐helices is adjusted. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Micro/nanomotors are attracting booming research enthusiasm with their revolutionary potential in biomedicine, sensing, and nanoengineering. Among the motors proposed, magnetic micro/nanomotors are of great interest with their high controllability and field biocompatibility. Yet the fabrication of magnetic actuated especially helical motors requires expensive and complicated instruments, 3D printing or glancing angle deposition, etc. Here, a soft and biocompatible helical poly(vinyl alcohol) (PVA) hydrogel motor via a versatile set‐up is engineered. The obtained helical hydrogel motor offers high capacity for chemokine CXCL12 and superparamagnetic iron oxide (Fe3O4) nanoparticles, which can then allow magnetic manipulation. With a low strength rotating magnetic field, the system is able to perform 3D precision navigation, necessary to steer the robotic system to a model diseased area. The chemokine cues from the hydrogel motor, acting as the synthetic leader cell, then directs immune T cell chemotactic migration. In a previously reported cell manipulating motor system, towing or pushing a single/two cell was demonstrated, with limited efficiency. This motor platform represents a novel approach for directing endogenous cell chemotaxis and organizing immune response. [ABSTRACT FROM AUTHOR]

In this study, we define two types of mappings that preserve the constant angle between the tangent vector field and the axis of a given helix in Euclidean spaces. The first type generates helices in the n‐dimensional Euclidean space from helices in the same space. The second type generates helices in the (n+1)‐dimensional Euclidean space from helices in the n‐dimensional Euclidean space. In addition, we give invariants of these mappings and study polynomial, rational, conical, ellipsoidal, and hyperboloidal helices supported by examples. [ABSTRACT FROM AUTHOR]

It is known that the geometric methods are used in most fields in natural sciences. Kinematics on curves and surfaces as one of these methods is an essential tool for investigating the growth of some biological objects. In this study, the time‐dependent and quaternionic models of accretive growth are considered. For this, first, it is defined as a growth velocity in the direction of the Darboux vector at every point on a spatial non‐null curve in three‐dimensional Lorentz–Minkowski spacetime. Second, accretive surface growth is presented through quaternions. With the help of the quaternionic form of the growth model, we reach that a point (cell tract) on the accretive surface makes a homothetic motion. Also, several examples and visualizations are given to support the theory. [ABSTRACT FROM AUTHOR]

[Display omitted] • An experimental/theoretical analysis was performed on the tripeptide Gly-Tyr-Gly. • Room-temperature Raman spectra of the tripeptide recorded in H 2 O and D 2 O were described. • Among the seven markers from the Tyr residue, attention was focused on the 850–830 cm−1 doublet. • The performances and deficiencies of three functionalsB3LYP, M062X and ωB97XD,were described. • The widely discussed reversal of the Tyr doublet relative intensity is of conformational nature, depending on the side chain χ 1 torsion angle. Tyrosine (Tyr) residue in a peptide chain is characterized by the presence of seven Raman markers, referred to as Y i (i = 1, ..., 7), distributed over the middle wavenumber spectral region. Particularly, the changes observed in the relative intensity of Y 5 and Y 6 markers, appearing as a side by side doublet at ca. 850–830 cm−1, has received a great attention. Primarily assigned to a Fermi-resonance effect between phenol ring planar and nonplanar modes, former density functional theory calculations led us to affiliate the Y 5 –Y 6 doublet to two distinct fundamental modes. Furthermore, despite the previous assumptions, it was evidenced that the reversal of the doublet intensity ratio cannot be solely explained by hydrogen bonding on the phenol hydroxyl group involved in Tyr. Herein, upon analyzing the observed and theoretical data collected from the cationic species of the tripeptide Gly-Tyr-Gly, the crucial effect of the aromatic side chain orientation, especially that of the χ 1 torsion angle defined around the C α C β bond, on the Tyr doublet intensity ratio has been evidenced. [ABSTRACT FROM AUTHOR]

Introducción: La reconstrucción auricular constituye un tema apasionante y representa todo un desafío para el Especialista en Cirugía Maxilofacial en la medicina moderna. Debido a su proyección y exposición fuera de la silueta corporal, el pabellón auricular es susceptible a una infinidad de injurias donde las traumáticas constituyen las más frecuentes. Presentación del caso: Se presenta el caso de una paciente femenina de treinta y dos años de edad con herida avulsiva de pabellón auricular izquierdo producto a mordedura humana, la cual se sometió a tratamiento quirúrgico optando como método reconstructivo por el colgajo retroauricular pediculado en mastoides descrito por Dieffenbach. Se realizó el procedimiento en dos secuencias terapéuticas obteniendo buenos resultados y plena satisfacción por parte del paciente. Conclusiones: La utilización de esta técnica representa un efectivo método de reconstrucción que cumple con principios importantes como un buen resultado estético y funcionabilidad, reforzando su gran versatilidad dentro del amplio espectro reconstructivo.

Eric Lord has observed: “In nature, helical structures arise when identical structural subunits combine sequentially, the orientational and translational relation between each unit and its predecessor remaining constant.” This paper proves Lord’s observation. Constant-time algorithms are given for the segmented helix generated from the intrinsic properties of a stacked object and its conjoining rule. Standard results from screw theory and previous work are combined with corollaries of Lord’s observation to allow calculations of segmented helices from either transformation matrices or four known consecutive points. The construction of these from the intrinsic properties of the rule for conjoining repeated subunits of arbitrary shape is provided, allowing the complete parameters describing the unique segmented helix generated by arbitrary stackings to be easily calculated. Free/Libre open-source interactive software and a website which performs this computation for arbitrary prisms along with interactive 3D visualization is provided. We prove that any subunit can produce a toroid-like helix or a maximally-extended helix, forming a continuous spectrum based on joint-face normal twist. This software, website and paper, taken together, compute, render, and catalog an exhaustive “zoo” of 28 uniquely-shaped platonic helices, such as the Boerdijk–Coxeter tetrahelix and various species of helices formed from dodecahedra.

The 3Cat-4 mission aims at demonstrating the capabilities of a CubeSat to perform Earth Observation (EO) by integrating a combined GNSS-R and Microwave Radiometer payload into a 1-Unit CubeSat. One of the greatest challenges is the design of an antenna that respects the 1-Unit CubeSat envelope while operating at the different frequency bands: Global Positioning System (GPS) L1 and Galileo E1 band (1575 MHz), GPS L2 band (1227 MHz), and the microwave radiometry band (1400–1427 MHz). Moreover, it requires between 8 and 12 dB of directivity depending on the band whilst providing at least 10 dB of front-to-back lobe ratio in L1 and L2 GPS bands. After a trade-off analysis on the type of antenna that could be used, a helix antenna was found to be the most suitable option to comply with the requirements, since it can be stowed during launch and deployed once in orbit. This article presents the antenna design from a radiation performance point of view starting with a theoretical analysis, then presenting the numerical simulations, the measurements in an Engineering Model (EM), and finally the final design and performance of the Flight Model (FM).

Alpha-synuclein (αS) is a membrane-binding protein found predominantly in neurons and erythrocytes. The protein remains unordered in aqueous solutions but folds into an α-helical structure when bound to membranes. Besides, it gets deposited as β-sheet rich aggregates in diseases known as synucleinopathies. The native αS has been reported to be acetylated at the N-terminus. Here, we compare the interfacial properties of the N-terminal acetylated αS (Ac-αS) with non-acetylated αS (NH 2 -αS) at the air-water interface. Both the protein forms are highly surface-active, with surface pressure reaching up to ~30 mN/m upon compression. The pressure-area isotherms obtained from the repeated compression-expansion cycles display large hysteresis suggesting self-assembly at higher surface pressures. The expansion isotherm is characterized by a rapid decrease in surface pressure followed by a slower transition phase starting around 15–17 mN/m. These data suggest that the compressed monolayer breaks into small clusters upon expansion, followed by these clusters' loosening. The circular dichroism spectroscopic analysis of the Blodgett-deposited films suggests the protein to be in largely α-helical conformation. The linear dichroism investigations suggest the protein to be anisotropically deposited. Blodgett deposition of the Langmuir films, therefore, is a rather simple method for preparing oriented monolayers of surface-active macromolecules. • The non-acetylated and N -acetylated α-synuclein display comparable surface activity. • The compression/expansion isotherms display large hysteresis, indicating surface pressure-induced self-assembly. • The self-assembled structures are rich in α-helical conformation. • The Blodgett-deposited protein films have a distinct helical orientation. [ABSTRACT FROM AUTHOR]

Magnesium oxide-reinforced wood fiber composites (MgO/WF) are a new type of multifunctional material, which can be used in different occasions, such as shopping malls, hotels, and residential buildings. Referring to the relevant literature, there is no research on the milling performance of MgO/WF. In order to better understand the relevant knowledge of the processability of MgO/WF, three cutters with different helix angles were used in this experiment to carry out the cutting of MgO/WF, and the variation trend of its cutting force, tool wear, and surface roughness was measured. The results are as follows: First, under the same cutting parameters, the resultant force decreases with the increase of helix angle. Second, with the increase of helix angle, the tool wear was slightly improved. Third, the surface roughness (Ra) showed an increasing trend with the decrease of helix angle. In the end, when milling MgO/WF, better machined surface quality and less tool wear can be obtained by selecting the tool with larger helix angle. [ABSTRACT FROM AUTHOR]

Two new complexes based on pipemidic acid (HPPA) and Co2+/Cd2+ ions, [Co(PPA)2]·2H2O (1) and Cd(PPA)2 (2), have been synthesized and structurally characterized. Single-crystal X-ray diffraction analysis shows that complexes 1 and 2 exhibit similar structures containing two-fold meso-helices and 1D supramolecular channels. The interaction of calf-thymus (CT-DNA) with complexes 1 and 2 with was explored by UV spectrum, and competitive studies with ethidium bromide (EB) by fluorescence spectrum. Notably, these results indicate that complexes 1 and 2 possess the higher binding DNA affinity than free HPPA drugs, maybe attributed to the coordinated metal ions and the helical channels. And the resultant hypochromism suggests the tight binding of 1 and 2 with CT-DNA probably by the intercalative mode. Moreover, the relatively high Ksv value also indicates that 1 and 2 can bind to CT-DNA for the intercalative binding sites. Two new complexes based on HPPA were synthesized and structural description, and exhibit similar structures containing two-fold meso-helices. The result of the interaction with CT-DNA indicates that complexes can bind to the CT-DNA by the intercalative mode and possess the higher binding constant to CT-DNA than free HPPA drugs. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a new class of curves that we call helical extension curve in Euclidean space. Then we investigate the differential geometric properties of the helical extension curves. The main result of the paper is that the helical extension curve of a helix is a plane curve. Moreover, we give several simple characterizations of helical extension curve of special curves such as spherical curve. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Chinese Society of Rare Earths is the property of Editorial Department of Journal of the Chinese Society of Rare Earths and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Inspired by the exquisite helices in Nature, fabrication of helical materials with controlled handedness has attracted considerable attention. Herein, we report on precis synthesis of single left‐ and right‐handed helical polyisocyanides through living polymerization of achiral monomers using chiral palladium catalysts under helix‐sense‐selective manner. Mechanism study revealed that the yielded helices with opposite handedness showed different activity of the living chain end. The helix with unfavored handedness was self‐terminated, while the one with favored handedness showed high activity and could undergo chain propagation to form a high molecular weight polymer with maintained single‐handed helicity. [ABSTRACT FROM AUTHOR]

In this study, we introduce the natural mate and conjugate mate of a Frenet curve in a three dimensional Lie group G with bi-invariant metric. Also, we give some relationships between a Frenet curve and its natural mate or its conjugate mate in G. Especially, we obtain some results for the natural mate and the conjugate mate of a Frenet curve in G when the Frenet curve is a general helix, a slant helix, a spherical curve, a rectifying curve, a Salkowski (constant curvature and non-constant torsion), anti-Salkowski (non-constant curvature and constant torsion), Bertrand curve. Finally, we give nice graphics with numeric solution in Euclidean 3-space as a commutative Lie group. [ABSTRACT FROM AUTHOR]

In this paper, we investigate helix and slant helices using non-degenerate curves in term of Sabban frame in de Sitter 3-space or Anti de Sitter 3-space M³(δ0). Furthermore, in M³(δ0) 3-space the necessary and sufficient conditions for the nondegenerate curves to be slant helix are given. [ABSTRACT FROM AUTHOR]

Wide beam and low axial ratio performance of printed quadrifilar antennas result in very attractive circularly polarised radiating element for wide scanned Electronically Steered Antenna. A compact printed quadrifilar Helix antenna (PQHA) has been designed and realised at S-Band frequency. Simulation and optimisation of designed antenna has been performed using ANSYS's high frequency structure simulation (HFSS) software for its impedance, axial ratio (AR) performance and radiation characteristics. The developed circularly polarised antenna has 3-dB beam width of 130° and peak gain of 3.4dBic at 2.6 GHz. The developed antenna shows excellent AR performance over the frequency band as well as over the radiated beam. Half power axial ratio bandwidth of developed antenna is 27.4% (2.2 GHz - 2.9 GHz) while the impedance bandwidth is 32% (2.1 GHz - 2.9 GHz). Design has been validated through measured results. Designed wide band PQHA can be used as radiating element for electronically steered antenna for large beam steering application. [ABSTRACT FROM AUTHOR]

Helical morphologies are widely observed in nature, however, it is very challenging to prepare artificial helical polymers. Especially, precisely understanding the structure information of artificial metal-free helical covalent inorganic polymers via single-crystal X-ray diffraction (SCXRD) analysis is rarely explored. Here, we successfully prepare a novel metal-free helical covalent inorganic polymer ({[Te(C 6 H 5 ) 2 ] [PO 3 (OH)]} n , named CityU-10) by introducing angular anions (HOPO 3 2- ) into traditional tellurium-oxygen chains. The dynamic reversibility of the reaction is realized through the introduction of organic tellurium precursor and the slow hydrolysis of polyphosphoric acid. High-quality and large-size single crystals of CityU-10 have been successfully characterized via SCXRD, where the same-handed helical inorganic polymer chains form a pseudo-two-dimensional layer via multiple hydrogen-bonding interactions. The left-handed layers and right-handed layers alternatively stack together through weak hydrogen bonds to form a three-dimensional supramolecular structure. The single crystals of CityU-10 are found to display promising optical properties with a large birefringence. Our results would offer new guidelines for designing and preparing new crystalline covalent polymers through tellurium-based chemistry., (© 2023 Wiley-VCH GmbH.)

Background: Daith piercing is a special ear-piercing method that punctures the crus of the helix. The penetrated site at the ear's innermost point is assumed to stimulate a pressure point associated with the vagus nerve. It has been reported that the pierced spot relieves migraine and tension-type headaches by activating vagal afferents, leading to the inhibition of neurons in the caudal trigeminal nucleus via the nucleus tractus solitarii., Objective: The objective of this narrative literature review is to summarize the current state of knowledge concerning daith piercing for the treatment of migraine and tension-type headaches from the perspectives of the Chinese and Western auricular systems., Methods: PubMed and China National Knowledge Infrastructure databases were searched using the keywords "daith piercing," "auricular points," "headache," and "acupuncture" from database inception to September 1, 2023. Only studies on humans were eligible; otherwise, no further restrictions were applied to the study designs, type of headache, or patient population of the identified articles. Bibliographies of all eligible studies were screened for further eligible studies. The main outcome of interest was a quantitative measure of pain relief by daith piercing. Secondary outcomes were relapse time of headache and further outcomes related to daith piercing, if available., Results: From a total of 186 identified articles, one retrospective study and three case reports fulfilled the inclusion criteria. No clinical trial was identified. The obtained studies describe patients experiencing chronic headaches undergoing daith piercing without changing or reducing their usual medication. In all case studies and the retrospective study, patients reported substantial reductions in pain immediately after daith piercing; however, headache symptoms recurred several weeks to months thereafter. From the perspective of the Chinese and Western auricular systems, no sufficient explanation for the described treatment effect of daith piercing was found., Conclusion: The available literature, combined with the reported recurrence of pain as well as the associated side effects of daith piercing, indicate that current evidence does not support daith piercing for the treatment of migraine, tension-type headaches, or other headache disorders., Plain Language Summary: This paper summarizes what we know about Daith piercing (DP) for chronic migraine and tension-type headache and discusses how DP might work. Current evidence does not support DP as an effective treatment of chronic migraine and tension-type headache. These findings might assist clinicians in discussing this subject with patients as well as guide future research., (© 2024 American Headache Society.)

Protein 3D structures support their biological functions. As the number of protein structures is negligible in regards to the number of available protein sequences, prediction methodologies relying only on protein sequences are essential tools. In this field, protein secondary structure prediction (PSSPs) is a mature area, and is considered to have reached a plateau. Nonetheless, proteins are highly dynamical macromolecules, a property that could impact the PSSP methods. Indeed, in a previous study, the stability of local protein conformations was evaluated demonstrating that some regions easily changed to another type of secondary structure. The protein sequences of this dataset were used by PSSPs and their results compared to molecular dynamics to investigate their potential impact on the quality of the secondary structure prediction. Interestingly, a direct link is observed between the quality of the prediction and the stability of the assignment to the secondary structure state. The more stable a local protein conformation is, the better the prediction will be. The secondary structure assignment not taken from the crystallized structures but from the conformations observed during the dynamics slightly increase the quality of the secondary structure prediction. These results show that evaluation of PSSPs can be done differently, but also that the notion of dynamics can be included in development of PSSPs and other approaches such as de novo approaches. Image 1 • Assessment of protein secondary structure prediction was done in the light of protein dynamics. • A direct link was observed between the quality of the prediction and the stability of the assignment to the secondary structure state. • More a local protein conformation was stable, better was the prediction. • The notion of dynamics can be included in development of protein secondary structure prediction and other approaches. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To design and evaluate a novel oxyntomodulin (OXM) derivative with albumin-binding helix domain and dual GLP-1 receptor (GLP-1R) and glucagon receptor (GcgR) activation activity to achieve metabolize improvement on the diabetes-related complication. MATERIALS AND METHODS: Mutation (D-Ser2) on OXM was performed and then different helix albumin-binding domains were fused to the mutated OXM via a thrombin-cleavable linker to generate seven fusion peptides, named LM01-LM07. Seven LM peptides were synthesized and screened via in vitro receptor activation test, albumin binding measurement and protease cleavage assay to select potent candidate peptide for further in vivo study. Moreover, acute and chronic efficacy studies were conducted to evaluate the efficacy of selected candidate using db/db mice. RESULTS: LM06, as selected OXM derivative, exhibited higher albumin-binding affinity, sustained-release efficiency and balanced activation activities on both GLP-1R and GcgR compared with other ones. Moreover, LM06 was demonstrated with improved hypoglycemic and insulinotropic abilities in receptor-deficient mice via activating GLP-1R. In addition, prolonged anti-diabetic efficacies of LM06 were demonstrated via hypoglycemic duration assay and OGTT in db/db mice. Further pharmacokinetic test of LM06 in both rats and monkeys identified improved half-life and other metabolic characteristics. Nevertheless, 8-week subcutaneously dosed LM06 in db/db mice achieved prominent efficacies on glucostasis, weight-lowering, pancreatic function and adipogenesis via activating GLP-1 R and GcgR. Moreover, LM06 also could accelerate diabetic skin wound closure in combination with low-intensity ultrasound. CONCLUSIONS: LM06, as a long-acting dual GLP-1 R/GcgR agonist, exerts potential as a once-weekly therapeutic candidate against diabetes-related complication in combination with low-intensity ultrasound. [ABSTRACT FROM AUTHOR]

This article focuses on analysing and modelling geometrically a complex vault typology known as single-row spherical dome, which was defined in several classic stereotomy treatises. The peculiarity of this kind of dome is that all their stone pieces are different, since there is a helical directrix defining the upper and lower edges of the pieces. Different solutions will be compared and analysed, both from a graphical and a mathematical point of view, by describing the spatial helixes. The accuracy of the different methods described in the treatises for tracing the stone templates will be also tested. To conclude, some examples of virtual 3D modellings and 3D printed models will be exposed. [ABSTRACT FROM AUTHOR]

Type 2 diabetes (T2D) and Alzheimer's disease (AD) belong to the 10 deadliest diseases and are sorely lacking in effective treatments. Both pathologies are part of the degenerative disorders named amyloidoses, which involve the misfolding and the aggregation of amyloid peptides, hIAPP for T2D and Aβ1‐42 for AD. While hIAPP and Aβ1‐42 inhibitors have been essentially designed to target β‐sheet‐rich structures composing the toxic amyloid oligomers and fibrils of these peptides, the strategy aiming at trapping the non‐toxic monomers in their helical native conformation has been rarely explored. We report herein the first example of helical foldamers as dual inhibitors of hIAPP and Aβ1‐42 aggregation and able to preserve the monomeric species of both amyloid peptides. A foldamer composed of 4‐amino(methyl)‐1,3‐thiazole‐5‐carboxylic acid (ATC) units, adopting a 9‐helix structure reminiscent of 310 helix, was remarkable as demonstrated by biophysical assays combining thioflavin‐T fluorescence, transmission electronic microscopy, capillary electrophoresis and mass spectrometry. [ABSTRACT FROM AUTHOR]

A series of single and double mutants generated on residues of a surfaced-exposed helix at the C-terminal domain of chondroitinase ABC I (cABC I) from proteus vulgaris. M886A, G887E, and their respective double mutant, MA/GE were inspired by the sequence of a similar helix segment in 30S ribosomal protein S1. Additionally, M889I, Q891K, and the corresponding double mutant, MI/QK, were made regarding the sequence of a similar helix in chondroitin lyase from Proteus mirabilis. Circular dichroism spectra in the far-UV region, demonstrate that the ordered structure of wild-type (WT), and double mutants are the same; however, the helicity of the ordered structures in MI/QK is higher than that of the WT enzyme. When compared with the single mutants, the double mutants showed higher activity, and that the activity of MI/QK is higher than that of the WT enzyme. Heat-induced denaturation experiments showed that the stability of the tertiary structure of double mutants at moderate temperatures is higher compared with the WT, and single mutants. It concluded that this helix can be considered as one of the hot spots region that can be more manipulated to obtain improved variants of cABC I. • A surfaced-exposed helix connects two organized sheets in chondroitinase ABC I. • The helix was replaced with similar variants found in other proteins. • Structural features of the mutants are changed compared with the WT enzyme. • It is a hot spot region, and can be manipulated to obtain improved enzyme variants. [ABSTRACT FROM AUTHOR]