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The extended phenotype of helical burrowing behavior in animals has evolved independently many times since the Cambrian explosion (~540 million years ago [MYA]). A number of hypotheses have been proposed to explain the evolution of helical burrowing in certain taxa, but no study has searched for a general explanation encompassing all taxa. We reviewed helical burrowing in both extant and extinct animals and from the trace fossil record and compiled 10 hypotheses for why animals construct helical burrows, including our own ideas. Of these, six are post‐construction hypotheses—benefits to the creator or offspring, realized after burrow construction—and four are construction hypotheses reflecting direct benefits to the creator during construction. We examine the fit of these hypotheses to a total of 21 extant taxa and ichnotaxa representing 59–184 possible species. Only two hypotheses, antipredator and biomechanical advantage, cannot be rejected for any species (possible in 100% of taxa), but six of the hypotheses cannot be rejected for most species (possible in 86%–100% of taxa): microclimate buffer, reduced falling sediment (soil), anticrowding, and vertical patch. Four of these six are construction hypotheses, raising the possibility that helical burrowing may have evolved without providing post‐construction benefits. Our analysis shows that increased drainage, deposit feeding, microbial farming, and offspring escape cannot explain helical burrowing behavior in the majority of taxa (5%–48%). Overall, the evidence does not support a general explanation for the evolution of helical burrowing in animals. The function and evolution of the helix as an extended phenotype seems to provide different advantages for different taxa in different environments under different physicochemical controls (some traces/tracemakers are discussed in more detail due to their association with body fossils and well‐constrained physicochemical parameters). Although direct tests of many of the hypotheses would be difficult, we nevertheless offer ways to test some of the hypotheses for selected taxa. [ABSTRACT FROM AUTHOR]

Circular dichroism (CD) studies on poly(1,4‐phenylene)s bearing a chiral side chain in the aggregated conditions were carried out. Little CD was observed in a solution form, while addition of a poor solvent into the polyphenylene solution induced aggregation and a strong CD was observed, accordingly. Applying the controlled degree of polymerization (DP) of poly(1,4‐phenylene) in the use of bidentate diphosphine Chiraphos as a ligand for the nickel catalyst, the relationship of DP with CD strength was studied to reveal to show the highest CD at the DP=84 (gabs=ca. 2×10−2). It was also found that the related aggregation was observed in good solvent 1,2‐dichloroethane upon standing the solution at 4 °C for 3–23 days to observe gabs=ca. 10−1. Studies on the substituent effect of poly(1,4‐phenylene) suggested that CD behaviors were dependent on the type of non‐chiral substituent on the aromatic ring as well as the side‐chain chirality. [ABSTRACT FROM AUTHOR]

Abstract The extended phenotype of helical burrowing behavior in animals has evolved independently many times since the Cambrian explosion (~540 million years ago [MYA]). A number of hypotheses have been proposed to explain the evolution of helical burrowing in certain taxa, but no study has searched for a general explanation encompassing all taxa. We reviewed helical burrowing in both extant and extinct animals and from the trace fossil record and compiled 10 hypotheses for why animals construct helical burrows, including our own ideas. Of these, six are post‐construction hypotheses—benefits to the creator or offspring, realized after burrow construction—and four are construction hypotheses reflecting direct benefits to the creator during construction. We examine the fit of these hypotheses to a total of 21 extant taxa and ichnotaxa representing 59–184 possible species. Only two hypotheses, antipredator and biomechanical advantage, cannot be rejected for any species (possible in 100% of taxa), but six of the hypotheses cannot be rejected for most species (possible in 86%–100% of taxa): microclimate buffer, reduced falling sediment (soil), anticrowding, and vertical patch. Four of these six are construction hypotheses, raising the possibility that helical burrowing may have evolved without providing post‐construction benefits. Our analysis shows that increased drainage, deposit feeding, microbial farming, and offspring escape cannot explain helical burrowing behavior in the majority of taxa (5%–48%). Overall, the evidence does not support a general explanation for the evolution of helical burrowing in animals. The function and evolution of the helix as an extended phenotype seems to provide different advantages for different taxa in different environments under different physicochemical controls (some traces/tracemakers are discussed in more detail due to their association with body fossils and well‐constrained physicochemical parameters). Although direct tests of many of the hypotheses would be difficult, we nevertheless offer ways to test some of the hypotheses for selected taxa.

As a type of transmission tower with excellent mechanical properties, steel tubular tower is widely used in engineering. However, when the length of steel tubular tower is relatively large and tends to be arranged horizontally, the steel tubular rod is prone to vortex-induced vibration at low wind speed. In the long run, the continuous and repeated vibration may cause fatigue damage to the steel tubular tower members. Once the tower structure is damaged, it will directly threaten the stable operation of the power grid. In order to solve this problem, two vortic-induced vibration pneumatic control measures of spiral turbulence and passive blowing sleeve are studied by using large size true steel pipe and rod through wind tunnel test. The influence law of different spiral number and pitch on vortex vibration control effect is analyzed. The influence of different orifice thickness and orifice shape on vortex vibration control is analyzed. The results show that the effect of single-helix control is not so good. The three-helix control can reduce the vortex vibration by 97.7% at most, and the hollow-loop control can reduce the vortex vibration by 75.5% at most. In this paper, a full-size model is used to meet the Reynolds number demand and realize the study closer to the real environment of steel pipe in transmission tower, providing reference for the vorticity vibration suppression of steel pipe in practical engineering. [ABSTRACT FROM AUTHOR]

This work demonstrates that the electrodeposition of highly stressed films on compliant ribbons is a robust process to obtain helical structures with excellent mechanical stability and potentially high thermal and electrical conductance. Electrodeposition on end‐tethered ribbons alters their axial and bending stiffness while imparting mechanical stress to drive the formation of a helix with a microscale diameter and pitch in a controlled and scalable manner. The process generates helices with diameters and pitches between 80 and 200 µm and lengths as large as several millimeters. The approach is amenable to parallel processing a large number of 3D structures on any substrate, including large‐area semiconductor wafers. This phenomenon is explained in terms of the change of stress gradients as material is added. Applications of the fabricated helices include antennas, metamaterials, and slow‐wave structures in frequency ranges not previously attainable. [ABSTRACT FROM AUTHOR]

The velocity of the gliding movement of filamentous cyanobacteria on a solid surface usually has a strong temperature dependency, and the higher the temperature, the faster the speed. Former studies on this phenomenon were conducted using filamentous cyanobacteria with straight morphology. We examined the velocity of the gliding movement of Arthrospira platensis NIES-39 along its longitudinal axis to see if the same was true for this cyanobacterium with helicoid trichomes. Experimental results showed little temperature dependency in the velocity in a wide temperature range in this cyanobacterium. However, when we examined the velocity using mutants with straight trichomes, their velocity was strongly affected by temperature, like other formerly analyzed filamentous cyanobacteria. This result indicates that the helicoid morphology of A. platensis trichomes confers temperature compensation to their migration velocity, enabling them to keep a relatively constant velocity under various temperatures. Migration of wild-type trichomes is considerably suppressed compared to the straight-trichome mutants on solid media. The temperature compensation in the locomotion of this organism appears to be established as part of such a suppression. It was also found that the velocity of this cyanobacterium depended on the trichome length when they were atypically short (<250 µm); the shorter the trichomes, the slower the gliding movement tended to be. This result indicates that the coordinated action of a high number of cells constituting the trichome is required for efficient gliding movement. [ABSTRACT FROM AUTHOR]

The aim of the work is to create a computer program in the 3D CAD system T Flex CAD allowing the creation of parametric models for the design and construction of a modular hob cutter for the selected gearing. The thesis includes the analysis of the problem of hob cutters for the production of spur gearing with an involute profile, the analysis of the initial surface and the shape of the tool cutting edge for the involute surface, the determination of the basic profile of the cutting edge of the hob cutter (geometry of the basic worm, geometry of the cutting edge) and the calculation of the design parameters of the tool. The individual calculations will be programmed in the 3D CAD system T Flex CAD, which will allow to generate a specific 3D model of the hob cutter based on the change of input requirements for the production of a given spur gear (module, engagement angle, tooth inclination angle), with the possibility of displaying the required tool in a 2D view in its base, normal and side planes, which will be in the form of a standard technical drawing. This paper presents the preparation (unification calculations, introduction) before the final version of the computer program for the creation of the parametric tool models. [ABSTRACT FROM AUTHOR]

The velocity of the gliding movement of filamentous cyanobacteria on a solid surface usually has a strong temperature dependency, and the higher the temperature, the faster the speed. Former studies on this phenomenon were conducted using filamentous cyanobacteria with straight morphology. We examined the velocity of the gliding movement of Arthrospira platensis NIES-39 along its longitudinal axis to see if the same was true for this cyanobacterium with helicoid trichomes. Experimental results showed little temperature dependency in the velocity in a wide temperature range in this cyanobacterium. However, when we examined the velocity using mutants with straight trichomes, their velocity was strongly affected by temperature, like other formerly analyzed filamentous cyanobacteria. This result indicates that the helicoid morphology of A. platensis trichomes confers temperature compensation to their migration velocity, enabling them to keep a relatively constant velocity under various temperatures. Migration of wild-type trichomes is considerably suppressed compared to the straight-trichome mutants on solid media. The temperature compensation in the locomotion of this organism appears to be established as part of such a suppression. It was also found that the velocity of this cyanobacterium depended on the trichome length when they were atypically short (

Polarimetric calibration is crucial to ensure the accuracy and reliability of subsequent application results. Since Gaofen-3(GF-3) has been providing polarimetric Synthetic Aperture Radar images for six years, it is necessary to monitor the polarimetric performance by estimating the residual channel imbalance. In this article, we proposed an improved algorithm based on zero helix component of Bragg-like targets. The method can provide transmitting and receiving channel imbalances results and can be applied to the large-scale polarimetric evaluation. We verified the effectiveness of the algorithm and assessed the residual channel imbalance in the multibeam polarimetric products of GF-3 quad-polarimetric Stripmap from 2019 to 2023. The experiments indicate that the residual channel imbalance changes in the same strip observation and the polarimetric performance remains stable. The evaluation conclusions can be used as references for subsequent application of GF-3 polarimetric products.

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(C6H5)2] [PO3(OH)]}n, named CityU‐10) by introducing angular anions (HOPO32−) 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. [ABSTRACT FROM AUTHOR]

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. Plain Language Summary: This paper summarizes what we know about Daith piercing (DP) for migraine and tension‐type headache and discusses how DP might work. Current evidence does not support DP as an effective treatment of migraine and tension‐type headache. These findings might assist clinicians in discussing this subject with patients as well as guide future research. [ABSTRACT FROM AUTHOR]

Wide band gaps with the propagation of elastic waves at low-frequency are desirable for phononic crystals in many traditional and novel applications. Inspired by the natural helix, we designed a microstructure in a metamaterial plate with an antisymmetric dual helix as the basic local resonant cell. The band structure and displacement transmission curve of metamaterial plates with dual helix cells were calculated by using the finite element method at first, then the band gap characteristics with and without consideration of the mass in the center of the dual helix were compared. The results show that the band gap in the band structure and displacement transmission curves have excellent consistency. Besides, the effects of the parameters including the number of turns of the helix, the plate thickness, and the radius of the attached mass sphere on the band gaps of flexural waves for the metamaterial plate were examined for further evaluation of the potential vibration prohibition application. It is found that the lower frequency of the band gap can be significantly tuned by adding a mass element in the metamaterial plates with dual helix elements, which provides a new method to tune the width of the band gap of a metamaterial plate. [ABSTRACT FROM AUTHOR]

Hydrogels are key components of biological tissues and have applications in biomedicine and commercial industry. Many biological tissues are known to strain harden due to the semiflexible nature of the chains. Here, the mechancial properties of poly‐l‐lysine (PLL) hydrogels, whose network chains undergo a random coil–helix transition, are studied as a function of the polypeptide's structural changes. PLL is cross‐linked with poly(ethylene glycol)diglycidyl ether at cross‐link percents ranging from 3% to 6%. The conformation change and mechanical properties are investigated with circular dichroism and small and large amplitude oscillatory shear rheology, respectively. As a function of pH at low cross‐link percents, a transition from strain softening to strain hardening is observed as the network chains become helical that is similar to the behavior of biological filamentous gels and consistent with recent theoretical descriptions of network strain hardening. At higher cross‐link densities, the hydrogels become brittle due to stress concentration in inhomogeneous locations in the network, which is studied with dynamic light scattering. Overall, the random coil–helix transition has a significant effect on the nonlinear mechanical properties of PLL hydrogels. By understanding the hydrogel structure and response to environmental changes, their potential can be expanded as functional biomedical materials. [ABSTRACT FROM AUTHOR]

The entry of the SARS-CoV-2 virus into a human host cell begins with the interaction between the viral spike protein (S protein) and human angiotensin-converting enzyme 2 (hACE2). Therefore, a possible strategy for the treatment of this infection is based on inhibiting the interaction of the two abovementioned proteins. Compounds that bind to the SARS-CoV-2 S protein at the interface with the alpha-1/alpha-2 helices of ACE2 PD Subdomain I are of particular interest. We present a stepwise optimisation of helical peptide foldamers containing trans-2-aminocylopentanecarboxylic acid residues as the folding-inducing unit. Four rounds of optimisation led to the discovery of an 18-amino-acid peptide with high affinity for the SARS-CoV-2 S protein (Kd = 650 nM) that inhibits this protein–protein interaction with IC50 = 1.3 µM. Circular dichroism and nuclear magnetic resonance studies indicated the helical conformation of this peptide in solution. [ABSTRACT FROM AUTHOR]

Mercury has high industrial utility and is present in many products, and environmental contamination and occupational exposure are widespread. There are numerous biological systems involved in the absorption, metabolism, and excretion of Hg, and it is possible that some systems may be impacted by genetic variation. If so, genotype may affect tissue concentrations of Hg and subsequent toxic effects. Genome-wide association testing was performed on blood Hg samples from pregnant women of the Avon Longitudinal Study of Parents and Children (n = 2893) and children of the Human Early Life Exposome (n = 1042). Directly-genotyped single-nucleotide polymorphisms (SNPs) were imputed to the Haplotype Reference Consortium r1.1 panel of whole genotypes and modelled againstlog-transformed Hg. Heritability was estimated using linkage disequilibrium score regression. The heritability of Hg was estimated as 24.0% (95% CI: 16.9% to 46.4%) in pregnant women, but could not be determined in children. There were 16 SNPs associated with Hg in pregnant women above a suggestive p-value threshold (p < 1 × 10−5), and 21 for children. However, no SNP passed this threshold in both studies, and none were genome-wide significant (p < 5 × 10−8). SNP-Hg associations were highly discordant between women and children, and this may reflect differences in metabolism, a gene–age interaction, or dose–response effects. Several suggestive variants had plausible links to Hg metabolism, such as rs146099921 in metal transporter SLC39A14, and two variants (rs28618224, rs7154700) in potassium voltage-gated channel genes. The findings would benefit from external validation, as suggestive results may contain both true associations and false positives. [ABSTRACT FROM AUTHOR]

A new kind of partner curves called osculating mate of a Frenet curve is introduced. Some characterizations for osculating mate are obtained and using the obtained results some special curves such as slant helix, spherical helix, C-slant helix and rectifying curve are constructed. [ABSTRACT FROM AUTHOR]

Background. Interest in the study of microwave metamaterials is associated with the possibility of using them to achieve the required frequency and polarization selective properties of interaction with electromagnetic radiation, which cant be obtained for structures based on homogeneous media. Aim. The mathematical model of a chiral metamaterial based on a periodic matrix of arbitrarily oriented conducting thin-wire cylindrical helices located in a homogeneous isotropic container creation is considered. Unlike known models, it takes into account the explicit form of the dependence of the effective permittivity and the relative chirality parameter on the helices concentration. Methods. The heterogeneity of a chiral metamaterial based on the Maxwell Garnett formula, which makes it possible to determine the effective dielectric permittivity from the permeabilities of the container and the region occupied by conducting mirror asymmetric inclusions is taken into account when creating a mathematical model. The dispersion of permittivity using the quadratic Lorentz formula and the dispersion of the chirality parameter based on the Condon model are taken into account. Results. Analytical frequency-dependent expressions for the effective permittivity and the chirality parameter taking into account the concentration of helices and their geometric parameters, were obtained in the work. The expression for the relationship between the dimensionless volume concentration of inclusions and the distance between adjacent elements is obtained. The quasi-static approach is used to calculate the resonant frequency of conducting thin-wire cylindrical helices. Conclusion. The proposed method for constructing a mathematical model can be applied to chiral metamaterials based on periodic matrices of conductive elements of an arbitrary mirror asymmetric spatial configuration

The entry of the SARS-CoV-2 virus into a human host cell begins with the interaction between the viral spike protein (S protein) and human angiotensin-converting enzyme 2 (hACE2). Therefore, a possible strategy for the treatment of this infection is based on inhibiting the interaction of the two abovementioned proteins. Compounds that bind to the SARS-CoV-2 S protein at the interface with the alpha-1/alpha-2 helices of ACE2 PD Subdomain I are of particular interest. We present a stepwise optimisation of helical peptide foldamers containing trans-2-aminocylopentanecarboxylic acid residues as the folding-inducing unit. Four rounds of optimisation led to the discovery of an 18-amino-acid peptide with high affinity for the SARS-CoV-2 S protein (Kd = 650 nM) that inhibits this protein–protein interaction with IC50 = 1.3 µM. Circular dichroism and nuclear magnetic resonance studies indicated the helical conformation of this peptide in solution.

Oligomers based on an aromatic ether derived ϵ‐amino acid peptides folded into herringbone helical structures, induced by successive NH−O−NH & O−NH−O bifurcated hydrogen bonding interactions and reinforced by π‐π stacking between aryls from adjacent layers. The diaryl ether bonds −O− worked both as structural units to provide turn motifs for changing the amplitude of the slope along the axis of helix for herringbone formation, and also as acceptors for hydrogen bonding. Attachment of a single chiral carbon to the C‐termini of the peptides induced excess of single‐handed screw sense and amplification through the chain propagation as exemplified by chain length dependent circular dichroism (CD) investigations. [ABSTRACT FROM AUTHOR]

Random walks (RWs) have been important in statistical physics and can describe the statistical properties of various processes in physical, chemical, and biological systems. In this study, we have proposed a self-interacting random walk model in a continuous three-dimensional space, where the walker and its previous visits interact according to a realistic Lennard-Jones (LJ) potential u L J r = ε r 0 / r 12 − 2 r 0 / r 6 . It is revealed that the model shows a novel globule-to-helix transition in addition to the well-known coil-to-globule collapse in its trajectory when the temperature decreases. The dependence of the structural transitions on the equilibrium distance r 0 of the LJ potential and the temperature T were extensively investigated. The system showed many different structural properties, including globule–coil, helix–globule–coil, and line–coil transitions depending on the equilibrium distance r 0 when the temperature T increases from low to high. We also obtained a correlation form of kBTc = λε for the relationship between the transition temperature Tc and the well depth ε , which is consistent with our numerical simulations. The implications of the random walk model on protein folding are also discussed. The present model provides a new way towards understanding the mechanism of helix formation in polymers like proteins. [ABSTRACT FROM AUTHOR]

Chiral resolution is very important and still a big challenge due to different biological activity and same physicochemical property of one pair (R)‐ and (S)‐isomer. There is no doubt that chiral selectors are essentially needed for chiral resolution, which can stereoselectively interact with a pair of isomers. To date, a large amount of optically active helical polymers as chiral selectors have been synthesized via two strategies. First, the target helical polymers are derived from natural polysaccharide such as cellulose and amylose. Second, they can be synthesized by polymerization of chiral monomers. Alternatively, an achiral polymer is prepared first followed by static or dynamic chiral induction. Furthermore, a part of them is harnessed as chiral stationary phases for chromatographic chiral separation and as chiral adsorbents for enantioselective adsorption/crystallization, resulting in good enantioseparation efficiency. In summary, the present review will focus on recent progress of the polymers with optical activity for chiral resolution, especially the literature published in the past 10 years. In addition, development prospects and future challenges of optically active helical polymers will be discussed in detail. [ABSTRACT FROM AUTHOR]

Optical fibres are generally used to provide a guided path to optical signals. Optical fibres are classified as multi-mode or single-mode fibres. Multi-mode graded index (GRIN) optical fibres have been prevalent in short-range optical networks, while single-mode GRIN fibres are used for long-range links. Another potential application of optical fibre is the optical delays in numerous applications, such as quantum computing, network buffering, data synchronization, pattern correlation, etc. This paper conceptualizes a novel application of an asymmetric GRIN optical fibre for possible enhanced optical delays. An asymmetric GRIN parabolic profile with helical structure geometry has been proposed for this task. A detailed analysis has been presented to investigate the effects of various parameters of the proposed geometry. Further, a guided propagation has also been demonstrated with the help of ray optics and the Helmholtz wave equation to assess the feasibility of the proposal. The presented investigations revealed that the geometrical length of the proposed structure is significantly compact compared with the traditional GRIN fibre, proving it beneficial for optical delays. [ABSTRACT FROM AUTHOR]

The management of mild cases of type Ⅰ to Ⅱ conchal microtia involves grafting cartilage to the affected ear to increase the cartilaginous area and transfer more skin to cover the larger cartilage. Herein, we performed a novel combined surgical procedure based on "subtractive thinking" that included antihelix reconstruction and outer helix reconstruction that was successful in patients with mild type I to II conchal microtia. From January 2018 to September 2022, 65 patients with mild, unilateral, type I to II conchal microtia were enrolled in this study. All patients were treated with a novel method at the Plastic Surgery Hospital of Peking Union Medical College. The perimeters, widths, and lengths of the healthy and affected ears were measured both preoperatively and postoperatively. Patients' levels of satisfaction were determined based on postoperative results. The mean postoperative follow-up duration was 14.9 ± 2.65 months. All patients experienced no complications. Analysis revealed that our surgical method could effectively treat mild type I to II concha microtia irrespective of the auricular perimeter, width, and length (p < 0.0001). Furthermore, the patient satisfaction rate was 100%. The combined surgical procedure, which includes antihelix and outer helix reconstructions, is a viable method of reconstructing type I to II auricular concha microtia. [ABSTRACT FROM AUTHOR]

The paper considers the solution of the problem of diffraction of the fundamental wave of a rectangular waveguide H10 on a planar transverse insert based on a chiral metamaterial created on the thin-wire conducting helices. To describe the chiral layer, a particular mathematical model is constructed that takes into account the properties of heterogeneity and dispersion of the permittivity and the chirality parameter of the artificial media. The well-known in physics model of Maxwell Garnett was used to take into account the heterogeneity property. To take into account the permittivity dispersion the Drude–Lorentz formula was applied and for the chirality parameter was used the Condon formula. The problem of diffraction of the rectangular waveguide main wave on a planar layer of a chiral metamaterial was solved by the partial regions method and was reduced to a system of linear algebraic equations for unknown reflection and transmission coefficients. It is shown that in the presence of a transverse chiral layer in the waveguide structure, a wave of the H01 type cross-polarized with respect to the main one arises. An analysis of the frequency dependences of the moduli of the reflection and transmission coefficients of the fundamental H10 and cross-polarized H01 showed that in some narrow frequency intervals in the single-mode gap, situations arise when the fundamental wave type is replaced from H10 to H01 near resonant frequencies. The transmission line under consideration can find application in the creation of frequency selective filters and polarization converters in the microwave range.

Chondrodermatitis nodularis helicis is a benign condition that presents as a painful ear nodule and is commonly seen in older adults. Herein, we highlight a pediatric case of chondrodermatitis nodularis helicis caused by an increasingly common age-related behavior of frequent headphone use.

In this study, we consider framed curves as regular or singular space curves with an adapted frame in Euclidean 3-space. We define framed natural mates of a framed curve that are tangent to the generalized principal normal of the framed curve. Subsequently, we present the relationships between a framed curve and its framed natural mates. In particular, we establish some necessary and sufficient conditions for the framed natural mates of specific framed curves, such as framed spherical curves, framed helices, framed slant helices, and framed rectifying curves. Finally, we support the concept with some examples. [ABSTRACT FROM AUTHOR]

Stabilization of Cu(I) is ubiquitous within native copper proteins. Understanding how to stabilize Cu(I) within synthetic biomimetic systems is therefore desired towards biological applications. Peptoids are an important class of peptodomimetics, that can bind metal ions and stabilize them in their high oxidation state. Thus, to date, they were not used for Cu(I) binding. Here we show how the helical peptoid hexamer, having two 2,2'‐bipyridine (Bipy) groups that face the same side of the helix, forms the intramolecular air stable Cu(I) complex. Further study of the binding site by rigorous spectroscopic techniques suggests that Cu(I) is tetracoordinated, binding to only three N atoms from the Bipy ligands and to the N‐terminus of the peptoid's backbone. A set of control peptoids and experiments indicates that the Cu(I) stability and selectivity are dictated by the intramolecular binding, forced by the helicity of the peptoid, which can be defined as the second coordination sphere of the metal center. [ABSTRACT FROM AUTHOR]

Helices are unique structures that play important roles in biomacromolecules and chiral catalysis. The mechanochemical unfolding of helical structures has attracted the attention of chemists in the past few years. However, it is limited to a few cases which investigated how the mechanochemical reactivity is impacted by helical configurations. No synthetic helical mechanophore is reported. Herein, a Zn (II) bidipyrrin (BDPR‐Zn) double helix is designed as a potential mechanophore. A cyclic olefin containing a doubly strapped BDPR‐Zn is prepared and used for ring‐opening metathesis polymerization. The corresponding polymer is subjected to pulsed ultrasonication for mechanochemical testing. The sonication results reveal the mechanochemical inertness of BDPR‐Zn unit, which is further supported by force‐coupled simulation. Although no obvious activation is observed, our preliminary results on BDPR‐Zn unit could inspire further rational designs on force‐induced helix unfolding. [ABSTRACT FROM AUTHOR]

This report aimed to introduce a very rare presentation of congenital aural fistula and its treatment. A 13-year-old girl presented with a mass on the right temporal region with protrusion of the helix. She noticed a mass a month previously, and the mass gradually swelled with pain. Pus discharged from the pit behind the helix. Mastoiditis was suspected; however, the tympanic membrane was normal. Magnetic resonance imaging revealed a cystic mass in the temporal region. The surgical removal of the mass was performed using a postauricular incision. The mass was cystic and had a stem connected to the pit. Insertion of a probe into the pit showed a connection to the mass. The mass was totally removed with the skin around the pit. Histologically, the cyst connected to the fistula and its lumen was covered with squamous cells. A diagnosis of a congenital aural fistula developed posterior to the helix was made. Considering its location, the fistula had been formed between the third and fourth hillocks of the embryonal helix. Aural fistula developed posteriorly is very rare, and it mimicked a temporal tumor or mastoiditis with a protruding auricle. Careful observation of the skin and consideration from developmental aspects are needed for an accurate diagnosis. [ABSTRACT FROM AUTHOR]

The sound field of a harmonically radiating monopole moving along arbitrary trajectories in three-dimensional space is studied in the frequency range and represented as a convolution integral in Cartesian coordinates. The observation time of the motion of the source can be finite or infinite. This convolution integral is referred to as the "Cartesian Convolution Integral " and is applied to point sources moving on special orbits described by circular and conical helices. For such helical orbits, an alternative approach in cylindrical or spherical coordinates leads to closed form expressions in the form of infinite series for the frequency spectra. The comparison of the results of the Cartesian Convolution Integral with those of the series expansion shows a very good agreement. Finally, the Cartesian Convolution Integral is used to calculate the spectral sound field of a source moving along an elliptical helix. [ABSTRACT FROM AUTHOR]

An acidic environment in bone is essential for bone metabolism and the production of decarboxylated osteocalcin, which functions as a regulatory hormone of glucose metabolism. Here, we describe the high‐resolution X‐ray crystal structure of decarboxylated osteocalcin under acidic conditions. Decarboxylated osteocalcin at pH 2.0 retains the α‐helix structure of native osteocalcin with three γ‐carboxyglutamic acid residues at neutral pH. This implies that decarboxylated osteocalcin is stable under an acidic environment in bone. In addition, site‐directed mutagenesis revealed that Glu17 and Glu21 are important for the adiponectin‐inducing activity of decarboxylated osteocalcin. These findings suggest that the receptor of decarboxylated osteocalcin responds to the negative charge in helix 1 of osteocalcin. [ABSTRACT FROM AUTHOR]

In this paper, we define the curve rλ = r + λd at a constant distance from the edge of regression on a curve r(s) with arc length parameter s in Galilean 3-space. Here, d is a non-isotropic or isotropic vector defined as a vector tightly fastened to Frenet trihedron of the curve r(s) in 3-dimensional Galilean space. We build the Frenet frame {Tλ, Nλ,Bλ} of the constructed curve rλ with respect to two types of the vector d and we indicate the properties related to the curvatures of the curve rλ. Also, for the curve rλ, we give the conditions to be a circular helix. Furthermore, we discuss ruled surfaces of type A generated via the curve rλ and the vector D which is defined as tangent of the curve rλ in 3-dimensional Galilean space. The constructed ruled surfaces also appear in two ways. The first is constructed with the curve rλ(s) = r(s) + λT(s) and the non-isotropic vector D. The second is formed by the curve rλ = r(s) + λ2N + λ3B and the non-isotropic vector D. We calculate the distribution parameters of the constructed ruled surfaces and we show that the ruled surfaces are developable. Finally, we provide examples and visuals to back up our research. [ABSTRACT FROM AUTHOR]

Helical piles are a kind of foundation that can withstand compression, tension, and lateral stresses. However, this kind of pile was utilized extensively globally for almost 25 years. Its behavior, particularly in Iraq, is uncertain and frightening. The current research used the finite element technique to analyze this kind of pile. The helical pile geometry was suggested to be modeled using the finite element method using the computer software Plaxis 3D The soil used is medium sandy soil. Additionally, parametric analyses were conducted. The primary parametric research examines the impact of helix number, helix spacing, helix diameter, and helix configuration under cyclic load. The main results are more helices in a pile, the lower the amplitude of settlement (in the direction of z) compared to a pile without helices. As a result, the amplitude of settlement in the case of two helices decreased by 81.6 %, while the amplitude of settlement in the case of three-helix decreased by 77.74 %. In the case of three helices, the higher spacing between the helices, the lower the value of the amplitude of settlement (in the direction of z). The effect of the number of helices in the hardening soil model is more than the effect of the number of helices in the Mohr-Coulomb. As a final result, increasing the number of helices in a pile has a more significant effect in reducing the amplitude of settlement than increasing the between the helices.

A dimeric cyclic cysteine analogue, i.e. (1R,1′R,2R,2′R)‐2,2′‐disulfanediylbis (aminocyclohexane‐1‐carboxylic acid), was used as a constrained unnatural amino acid and as a folding inducer in ultra‐short Leu‐Val‐containing peptide. Our results showed that both free dimer amino acid L1 and its peptide derivative L2 are able to chelate Cu(II). The obtained complexes resulted to be catalytically active in Michael addition reaction of nitromethane on different types of chalcones. L1‐Cu(II) was shown more reactive in terms of conversion, while, in neat conditions, L2‐Cu(II) allows to obtain an interesting 60 % e.e. on pyridine chalcone. [ABSTRACT FROM AUTHOR]

In this paper we generalize the notion of helix in the three-dimensional Euclidean space, which we define as that curve α for which there is an F -constant vector field W along α that forms a constant angle with a fixed direction V (called an axis of the helix). We find the natural equation and the geometric integration of helices α where the F -constant vector field W is orthogonal to its axis. [ABSTRACT FROM AUTHOR]

Plasmene is recently defined as 2D arrays of plasmonic nanoparticles, which could be fabricated by the bottom‐up self‐assembly approach and demonstrated a wide range of applications in sensing, energy harvesting, nanophotonics and encryption. Herein, this work further demonstrates a 3D helical plasmonic nanostructures that can be fabricated from 2D plasmene nanosheet. Inspired by chocolate curls‐making process, a micro‐spatula‐based strategy is developed to selectively scrape substrate‐supported plasmene to free space, which spontaneously folds the plasmene nanosheet into various complex helical nanostructures with controlled dimensions. 3D nanospirals can also be obtained by focus ion beam (FIB)‐based lithography on free‐standing plasmene. Helical plasmene structures are robust, exhibiting elastic mechanical properties and chiral optical response. This methodology represents a versatile fabrication route combining both bottom‐up and top‐down approaches to create soft plasmonic helical structures for potential applications in next‐generation flexible nanophotonic devices. [ABSTRACT FROM AUTHOR]

An essay, part retrospective part prospectus, focusing on a production of an experimental stage drama using and innovating techniques of dramaturgical improvisation conflating drama and music. The essay uses extracts from the play to analyse and demonstrate the techniques discussed. Reviews of the play and its adaptation into prose, and reminiscences from participants also help contextualise the production. [ABSTRACT FROM AUTHOR]

The calibration of channel imbalances is currently the main concern in polarimetric calibration (POLCAL) since the crosstalk of recent polarimetric synthetic aperture radar (Pol-SAR) systems is lower than −20 dB. The existing channel imbalance calibration method without corner reflectors utilizes both volume-dominated and Bragg-like targets. However, there are two limitations to using volume-dominated targets. One is that the inaccurate selection of volume-dominated areas in the uncalibrated Pol-SAR images has a negative influence on the estimation of cross-polarization (x-pol) channel imbalance, which subsequently impacts the estimation of copolarization (copol) channel imbalance. The other is that there are minimal volume-dominated areas in some special applications of Pol-SAR, such as planetary exploration. Thus, only selecting Bragg-like targets to estimate the values of both transmitting and receiving channel imbalances, which is proposed in this paper, can avoid the uncertainty brought about by selecting other distributed targets in an uncalibrated imaginary. In addition, the reciprocity assumption and characteristics corresponding to H/ α ¯  decomposition are introduced to eliminate the phase ambiguity for the first time. Compared with previous methods, our method had an obvious advantage in terms of universality, since Bragg-like targets are common in the most illuminating areas. The novel method was applied to both the simulated data from the L-band Advanced Land Observing Satellite (ALOS) and C-band GaoFen-3 (GF-3), and to real data with corner reflectors on site. The results from the simulated data showed that the errors of the amplitude and phase estimation were less than 0.5 dB and 5.0° in most topographical features. Meanwhile, the  V V / H H  terms from all trihedral corner reflectors were less than 0.3 dB for amplitude, and 5.5° for phase after calibration by using the estimated channel imbalances. [ABSTRACT FROM AUTHOR]

Knowledge of the 3D structure of proteins is a valuable asset for understanding their precise biological mechanisms. However, the cost of production of 3D structures and experimental difficulties limit their obtaining. The proposal of 3D structural models is consequently an appealing alternative. The release of the AlphaFold Deep Learning approach has revolutionized the field. The recent near-complete human proteome proposal makes it possible to analyse large amounts of data and evaluate the results of the approach in greater depth. The 3D human proteome was thus analysed in light of the classic secondary structures, and many less-used protein local conformations (PolyProline II helices, type of γ-turns, of β-turns and of β-bulges, curvature of the helices, and a structural alphabet). Without questioning the global quality of the approach, this analysis highlights certain local conformations, which maybe poorly predicted and they could therefore be better addressed. [Display omitted] • Fine analyses of AlphaFold2 structural models made in the light of local protein conformations. • PolyProline II helices are often encountered with a low confidence index. • Some less classical local protein conformations are found with low confidence index, i.e. γ-turns and cis ω angles. • Potentiality of an under-representation of β-sheet while the corresponding Protein Blocks have correct occurrences. [ABSTRACT FROM AUTHOR]

Inspired by biological helices (e.g., DNA), artificial helical polymers have attracted intense attention. However, precise synthesis of one‐handed helices from achiral materials remains a formidable challenge. Herein, a series of achiral poly(biphenyl allene)s with controlled molar mass and low dispersity were prepared and induced into one‐handed helices using chiral amines and alcohols. The induced one‐handed helix was simultaneously memorized, even after the chiral inducer was removed. The switchable induction processes were visible to naked eye; the achiral polymers exhibited blue emission (irradiated at 365 nm), whereas the induced one‐handed helices exhibited cyan emission with clear circularly polarized luminescence. The induced helices formed stable gels in various solvents with helicity discrimination ability: the same‐handed helix gels were self‐healing, whereas the gels of opposite‐handed helicity were self‐sorted. Moreover, the induced helices could separate enantiomers via enantioselective crystallization with high efficiency and switchable enantioselectivity. [ABSTRACT FROM AUTHOR]