Ring Spacing Research Articles

Multicomponent reactions (MCRs) yielding medicinally relevant rings: a recent update and chemical space analysis of the scaffolds.

In this review we have compiled multicomponent reactions (MCRs) that produce cyclic structures. We have covered articles reported since 2019 to showcase the recent advances in this area. In contrast to other available reviews on this topic, we focus specifically on MCRs with strong prospects in medicinal chemistry. Consequently, the reactions operating in a single-pot and yielding novel rings or new substitution patterns under mild conditions are highlighted. Moreover, MCRs that do not require special reagents or catalysts and yield diverse products from commercially available building blocks are reviewed. The synthetic schemes, substrate scope, and other key aspects such as regio- and stereoselectivity are discussed for each MCR. Using cheminformatic tools, we have also attempted to characterize the chemical space of the scaffolds obtained from these MCRs. We show that the MCR scaffolds are novel, more complex, and globular in shape compared to the approved drugs and clinical candidates. Thus, our review represents a step towards identifying and characterizing the novel ring space that can be accessed efficiently through MCRs in a short timeframe.

Interaction of travelling waves in multilayer networks

In this paper, we explore numerically the impact of different types of inter-layer coupling on the dynamics of a two-layer multiplex network of coupled FitzHugh–Nagumo oscillators in the excitable regime. For this purpose, the cases of attractive, repulsive, and periodically modulated inter-layer coupling are considered. Coupled in the ring structure, the FitzHugh–Nagumo neurons demonstrate travelling wave regimes which are different for the attractive and repulsive intra-layer coupling. It is shown that the inter-layer coupling affects not only the frequency of oscillations of individual neurons but also the spatio-temporal structures in individual layers in different ways, depending on the sign of the inter-layer coupling. It is established that complete in-phase synchronization of travelling waves is well achieved in the presence of attractive inter-layer coupling, while the repulsive inter-layer coupling induces effective anti-phase synchronization of wave regimes. When the inter-layer coupling is periodically modulated, the wave structures in both layers are distorted, and clusters of coherent and incoherent dynamics can appear in the ring space. The paper was presented at PhysCon2024.

Construction of Alkaloid-Type Bis Carbazoles via Pd(II)-Catalyzed C-H Functionalization.

We report the construction of unsymmetrical dimeric carbazoles and π-extended bis carbazoles (having an aryl ring spacer) via the C-H functionalization route. Generally, oxidative coupling and traditional cross-coupling reactions have been used to construct bis- and π-extended carbazoles. Natural bis carbazole alkaloids and synthetic dimeric carbazoles are important molecules in medicinal, materials chemistry research. There is scope for developing new synthetic transformations leading to structurally appealing bis carbazoles. The synthesis of symmetrical bis carbazoles via cross-coupling and C-H functionalization is well known in the literature and it is noted that there exist limited reports on the construction of unsymmetrical bis carbazoles via the C-H functionalization route. Accordingly, this paper reveals the Pd(II)-catalyzed bidentate directing group-assisted C-H functionalization as a progressive route for the synthesis of a library of unsymmetrical dimeric carbazoles and π-extended bis carbazoles (connected through an aryl ring spacer).

Quantitative characterization method of point cloud distribution in tunnel for optimizing TLS scanning plan

A novel method for quantitatively describing the distribution of point clouds in tunnels is introduced to optimize tunnel scanning schemes. The method uses point cloud spacing and thickness to represent the density and unevenness of the point cloud, respectively. Point cloud spacing is categorized into point spacing and ring spacing based on the scanning trajectory, and these metrics are calculated using coordinates from a regularly distributed point cloud. Point cloud thickness is derived by combining the measurement error range in the laser incidence direction with the laser incidence angle. The above calculation method has been validated through tunnel field tests. The quantitative characterization method evaluates the effects of resolution, station spacing, and linearity error on point cloud spacing and thickness. It helps determine the necessary resolution, station spacing, and TLS scanner specifications to ensure that point cloud spacing and thickness meet the requirements for tunnel health assessment. By addressing the lack of comprehensive quantitative consideration of point cloud distribution in selecting scanning parameters, this method provides a robust framework for optimizing scanning schemes, ensuring accurate and reliable point cloud data for tunnel inspection.

Research on the Construction Mechanics and Stability Control Technology of Expressway Tunnel Based on Numerical Analysis

As an effective structural form, connecting arch tunnel has been widely used in practical engineering because of its smooth linear shape, small footprint and good bridge and tunnel connection. With the increase of domestic traffic volume year by year, the width of the even arch tunnel is gradually changed from two-way four lanes to two-way six lanes. I20 I-steel, spacing 0.75∼1 m, anchor length 3∼4 m, ring spacing 0.5∼1 m, the side ring spacing of the middle wall is 0.75 m, the side ring spacing of the side wall is 1 m, and the shotcrete thickness is 0.25∼0.3 m. The excavation span of a two-way six-lane continuous-arch tunnel is considerable, leading to complex stress characteristics, thereby posing risks to construction safety and structural stability. Following the construction of the initial tunnel, disturbance to the surrounding rock occurs, affecting subsequent excavation phases. The initial support requirements for subsequent excavations are more intricate, with increased internal forces compared to the initial tunnel segment. As the rear tunnel progresses, the surrounding rock near the middle wall shifts towards the rear tunnel, reducing internal forces in the concrete and steel arch frame. However, as the rear tunnel distance increases, concrete stress and axial forces on the middle wall side of the initial tunnel begin to rise. Throughout the construction, the steel arch frame’s internal forces and spray concrete stress on the middle wall side’s arch waist and foot are the highest, making them susceptible to disruption from construction on the opposite side, thus constituting critical tunnel components. Numerical simulations effectively capture surrounding rock and structural stress dynamics during large-span arch tunnel construction. Simulation outcomes align closely with field measurements, particularly in three-dimensional simulations, enhancing construction understanding and management.

Bionic Design and Adsorption Performance Analysis of Vacuum Suckers.

This study addresses the problem that the traditional method is not effective in improving the adsorption performance of vacuum suckers. From the perspective of bionics, the adsorption performance of bionic suckers based on the excellent adsorption of the abalone abdominal foot was studied. A bionic sucker was designed by extracting the sealing ring structure of the abdominal foot tentacle. The bionic sucker was subjected to tensile experiments using an orthogonal experimental design, and the adsorption of the bionic sucker was simulated and analyzed to explore its adsorption mechanism. The results show that the primary and secondary factors affecting the adsorption of the sucker are the number of sealing rings, the width of sealing rings and the spacing of sealing rings. At 60% vacuum, the bionic sucker with two sealing rings, a 1.5 mm sealing ring width and 3 mm sealing ring spacing has the largest adsorption force, and its maximum adsorption force is 15.8% higher than that of the standard sucker. This study shows that the bionic sucker design can effectively improve the adsorption performance of the sucker. The bionic sucker had a different stress distribution on the sucker bottom, which resulted in greater Mises stress in the sealing ring and the surrounding area, while the Mises stress in the central area of the sucker was smaller.

The novel impedance matching device realized by the structure of air-gap ring based on the doping method at microwave frequency

The doping method enabled the epsilon-near-zero (ENZ) medium to adjust its permeability effectively. In this study, we theoretically analyze that the gap ring structure formed by the ENZ medium doped with perfect electrical conductor (PEC) can be equivalent to the controllable series reactance. Based on this concept, a universal matching network that can match any complex impedance load by adjusting the gap ring spacing is constructed. We used the above universal matching network to carry out theoretical and simulation calculations on the matching effect of a random-sized stepped waveguide and horn antenna, and the results show that the impedance-matching technology has a good matching effect for different loads. Finally, experimental verification is carried out. Compared with traditional impedance-matching networks, the proposed structure has the characteristics of simplicity, reliability, low loss, high carrying power, low preparation requirements, and good application prospects. This work is a good example of the practicality of ENZ media and also provides a very meaningful idea for the development of new electromagnetic matching devices.

Single-Crystal Structure Analysis of Dicarboxamides: Impact of Heteroatoms on Hydrogen Bonding of Carboxamide Groups

This research examines how heteroatoms in a six- or five-membered pyridine, thiophene or furan ring spacer between two carboxamide groups influence the hydrogen bonding for advancements in supramolecular chemistry and drug development. The solvent-free crystal structures of 3,5-pyridinedicarboxamide (PDC), 2,5-thiophenedicarboxamide (TDC) and 2,5-furandicarboxamide (FDC-subl, crystallized by sublimation), and the monohydrate structure of FDC-solv (crystallized from methanol) are described with the hydrogen-bonding analyzed by the Etter graph-set notation. The carbon atoms of the amide groups form an angle of 121° in PDC, 151° in TDC, 137° in FDC-solv and 135° in FDC-subl with the ring centroid. Only in the structure of PDC does the heteroatom act as an H-bond acceptor as part of a C11(6) chain. In TDC and FDC, the heteroatoms do not interact with the amide -NH2 groups.

Cubic Structure on Soft Gamma-m-Normed Linear Space

Objectives: The purpose of this research is to take the lead in comprehending the fuzzy idea of cubic structure on soft Gamma-m normed linear space. According to the theory of Soft m-Normed Linear Space (SMNLS), we offer the conviction of Cauchy's sequence and convergence in cubic Soft Gamma-m Normed Linear Space (CSGMNLS). We have obtained certain results like the concept of completeness in CSGMNLS. Methods: In this paper we defined the soft gamma ring, soft gamma ideals and soft gamma vector space which are used to introduce the notion of soft gamma-2-normed linear space, Soft Gamma-m-Normed Linear Space (SGMNLS) and its properties. Also, the CSGMNLS can be analyzed by using the SGMNLS. Findings: In this research from CSGMNLS construct a norm function that satisfies the properties of SGMNLS, and additionally given that example with proof in which a sequence is cauchy sequence and convergence in SGMNLS if it is cauchy and convergence sequence in CSGMNLS. Also, provided theorem and its proof for completeness of a sequence in CSGMNLS. Novelty: Already gamma ring and fuzzy n-normed linear space has been defined. We introduced the concept of SGMNLS using this also initiated the CSGMNLS and some results obtained from its properties. We suggested a necessary conditions for completeness of a sequence in CSGMNLS. Keywords: Soft Gamma ring, Soft gamma vector space, Soft gamma normed linear space, Soft m-norm, Soft m-normed linear space, 2-Normed and m-normed right soft gamma linear space

Design and Test of Automatic Feeding Device for Shed Pole of Small-Arched Insertion Machine

China’s small-arched shed-building machinery mostly adopts manual pole casting and mechanical planting, which have low building efficiency and mechanization. Therefore, we designed an automatic feeding device for shed poles to realize automatic single separation, orderly conveyance and timely dropping of poles. Considering shed pole-pitching pass rate as the evaluation index for the regression model, we adopted a three-factor, three-level experimental design and established the speed of the reclaiming ring, height of the falling shed poles and reclaiming ring spacing as the main influencing factors, obtaining 23.94 r/min, 408.799 mm and 1350 mm, respectively in experiments with a trellis qualification rate of 95.36%. Design-Expert 13 was used to perform analysis of variance and determine the optimal parameter combinations. The average measured trellis qualification rate in tests with the bench adjusted and the optimal parameter combination was 94.23%, with 1.13% relative error between test and theoretical optimization values. This confirmed the optimal parameter combination’s dependability. In field verification test results, pick-up card ring speed was 24 r/min; height of trellis pole drop, 410 mm; pick-up card ring spacing, 1350 mm; and pitching rate, 95.37%, obtaining 0.01% error compared with theoretically optimized values. The prototype operational performance was stable and satisfied design requirements.

Exact approaches to solve the Transmission Expansion Planning Problem with Re-design

Expanding electrical transmission networks is a critical challenge faced by many developing economies. This process requires extensive investments, which must be strategically and methodically planned on a large scale, often encompassing regional or national considerations. Differing from typical Network Design Problems, efficiency in a transmission network can sometimes be enhanced by strategically deactivating certain transmission lines. Thanks to that, this paper focuses on a version of the transmission expansion planning problem that allows redesign during the network expansion. We propose using two exact methodologies as alternatives to the direct use of mixed integer programming formulations with commercial solvers. These methods are an application of Benders’ decomposition and a newly developed approach named Ring Space. Through comprehensive computational experiments, we assess and compare the efficacy of these methods against the conventional application of the mathematical formulation. Additionally, this study successfully obtained new high-quality solutions and proved their optimality for a subset of benchmark instances.

Dynamical systems for arithmetic schemes

Motivated by work of Kucharczyk and Scholze, we use sheafified rational Witt vector rings to attach a new ringed space Wrat(X) to every scheme X. We also define R-valued points Wrat(X)(R) of Wrat(X) for every commutative ring R. For normal schemes X of finite type over specZ, using Wrat(X)(ℂ) we construct infinite dimensional R-dynamical systems whose periodic orbits are related to the closed points of X. Various aspects of these topological dynamical systems are studied. We also explain how certain p-adic points of Wrat(X) for X the spectrum of a p-adic local number ring are related to the points of the Fargues–Fontaine curve.

Analysis and Enlightenment on the Relationships between Two Kinds of Cutter Life Evaluation Indexes and Installation Radius: A Case Study

Accurate evaluation of cutter life at different cutter positions on the cutter head is helpful to determine the time of cutter change and reduce the time of cutter wear measurement, which is of great significance to improve the tunneling efficiency of tunnel boring machine (TBM) projects. Unfortunately, there is no unified cutter life evaluation index now. The field data of cutter wear are collected from a section of a long TBM tunneling water conveyance tunnel in China. Two kinds of cutter life evaluation indexes (based on the radial wear extent of cutter rings and replacement number of cutter rings) are selected and the variation rule between these two kinds of indexes with cutter installation radius is statistically analyzed. The results show that the regression relationships between the two kinds of cutter life evaluation indexes and installation radius mainly present linear functions and quadratic functions. Those regression relationships are affected by factors such as wear type, installation angle, cutter spacing, influence width, and allowable limit wear extent of cutter rings. Considering the calculation accuracy of the evaluation index, the actual working conditions of the disc cutter, and ignoring the influence of tunnel diameter, it is recommended to preferentially choose the radial wear extent of cutter rings per unit rolling distance as the evaluation index of cutter life. The research results can provide a reference for the selection of cutter life evaluation index, prediction of disc cutter life at different cutter positions, and establishment of cutter life prediction mode.

Noncommutative spaces for parafermions

We introduce ringed spaces, referred to as para-manifolds, whose non-commutative nilpotent coordinates naturally describe parafermions at the classical level in a similar way as Grassmann variables describe usual fermions. Given a supermanifold X, we construct a family of para-manifolds X(p) for positive integers p, such that X(1) recovers the supermanifold itself. A differential analysis on para-manifolds is developed, which can be readily applied to model physical problems. Two classes of para-manifolds, respectively corresponding to X being affine superspaces and projective superspaces, are treated in detail as examples. Green's theory of parafermions is reformulated in terms of para-manifolds.

A connectedness theorem for spaces of valuation rings

Let F be a field, let D be a local subring of F, and let ValF(D) be the space of valuation rings of F that dominate D. We lift Zariski's connectedness theorem for fibers of a projective morphism to the Zariski-Riemann space of valuation rings of F by proving that a subring R of F dominating D is local, residually algebraic over D and integrally closed in F if and only if there is a closed and connected subspace Z of ValF(D) such that R is the intersection of the rings in Z. Consequently, the intersection of the rings in any closed and connected subset of ValF(D) is a local ring. In proving this, we also prove a converse to Zariski's connectedness theorem. Our results do not require the rings involved to be Noetherian.

Study on the Synergistic Effect of Primary Support and Surrounding Rock of Large Buried Depth Tunnel in Soft and Fractured Strata

The soft and fractured strata can cause significant deformation of surrounding rock during tunnel excavation. This study analyzes field monitoring test results and compares numerical simulations from the third bid project of the Dali I section construction within the water diversion project in central Yunnan to address the issue of significant deformation following tunnel excavation in soft and fractured strata. It proposes an optimized support scheme consisting of a densified steel arch and enhanced initial support strength and stiffness. In addition, the research investigates support effectiveness considering varying support strengths and steel arch ring spacing. The study findings indicated the following: (1) The tunnel traverses soft and fractured strata, causing unevenly distributed vertical convergence deformation around the cavern. The maximum settlement occurs at the crown, showing pronounced nonlinearity. (2) The maximum stress in the steel arch is concentrated at the arch crown, measuring −19.02 MPa. The arch remains compressed, with stress decreasing from the crown to the waist. (3) The axial force in the anchor bolt reduces from the crown to the arch’s waist on both sides. As the depth of the rock mass increases, the axial force in each anchor bolt decreases and the tension state is maintained. The maximum axial force reaches 46.57 kN. (4) The maximum displacement decreases from 4.21 to 0.15 cm after the optimized support structure is implemented, demonstrating the optimization scheme’s effectiveness. Future constructions can refer to this scheme and make necessary adjustments based on various terrain conditions to ensure safety.

The Conductance Isotope Effect in Oligophenylene Imine Molecular Wires Depends on the Number and Spacing of 13C-Labeled Phenylene Rings.

We report a strong and structurally sensitive 13C intramolecular conductance isotope effect (CIE) for oligophenyleneimine (OPI) molecular wires connected to Au electrodes. Wires were built from Au surfaces beginning with the formation of 4-aminothiophenol self-assembled monolayers (SAMs) followed by subsequent condensation reactions with 13C-labeled terephthalaldehyde and phenylenediamine; in these monomers the phenylene rings were either completely 13C-labeled or the naturally abundant 12C isotopologues. Alternatively, perdeuterated versions of terephthalaldehyde and phenylenediamine were employed to make 2H(D)-labeled OPI wires. For 13C-isotopologues of short OPI wires (<4 nm) in length where the charge transport mechanism is tunneling, there was no measurable effect, i.e., 13C CIE ≈ 1, where CIE is defined as the ratio of labeled and unlabeled wire resistances, i.e., CIE = Rheavy/Rlight. However, for long OPI wires >4 nm, in which the transport mechanism is polaron hopping, a strong 13C CIE = 4-5 was observed. A much weaker inverse CIE < 1 was evident for the longest D-labeled wires. Importantly, the magnitude of the 13C CIE was sensitive to the number and spacing of 13C-labeled rings, i.e., the CIE was structurally sensitive. The structural sensitivity is intriguing because it may be employed to understand polaron hopping mechanisms and charge localization/delocalization in molecular wires. A preliminary theoretical analysis explored several possible explanations for the CIE, but so far a fully satisfactory explanation has not been identified. Nevertheless, the latest results unambiguously demonstrate structural sensitivity of the heavy atom CIE, offering directions for further utilization of this interesting effect.

Combining Experimental and Computational Methods to Produce Conjugates of Anticholinesterase and Antioxidant Pharmacophores with Linker Chemistries Affecting Biological Activities Related to Treatment of Alzheimer's Disease.

Effective therapeutics for Alzheimer's disease (AD) are in great demand worldwide. In our previous work, we responded to this need by synthesizing novel drug candidates consisting of 4-amino-2,3-polymethylenequinolines conjugated with butylated hydroxytoluene via fixed-length alkylimine or alkylamine linkers (spacers) and studying their bioactivities pertaining to AD treatment. Here, we report significant extensions of these studies, including the use of variable-length spacers and more detailed biological characterizations. Conjugates were potent inhibitors of acetylcholinesterase (AChE, the most active was 17d IC50 15.1 ± 0.2 nM) and butyrylcholinesterase (BChE, the most active was 18d: IC50 5.96 ± 0.58 nM), with weak inhibition of off-target carboxylesterase. Conjugates with alkylamine spacers were more effective cholinesterase inhibitors than alkylimine analogs. Optimal inhibition for AChE was exhibited by cyclohexaquinoline and for BChE by cycloheptaquinoline. Increasing spacer length elevated the potency against both cholinesterases. Structure-activity relationships agreed with docking results. Mixed-type reversible AChE inhibition, dual docking to catalytic and peripheral anionic sites, and propidium iodide displacement suggested the potential of hybrids to block AChE-induced β-amyloid (Aβ) aggregation. Hybrids also exhibited the inhibition of Aβ self-aggregation in the thioflavin test; those with a hexaquinoline ring and C8 spacer were the most active. Conjugates demonstrated high antioxidant activity in ABTS and FRAP assays as well as the inhibition of luminol chemiluminescence and lipid peroxidation in mouse brain homogenates. Quantum-chemical calculations explained antioxidant results. Computed ADMET profiles indicated favorable blood-brain barrier permeability, suggesting the CNS activity potential. Thus, the conjugates could be considered promising multifunctional agents for the potential treatment of AD.

Understanding factors affecting the process efficiency, quality and carbon emission in laser drilling of CFRP composite via tailored sequence multiple-ring scanning

Carbon fibre reinforced polymer (CFRP) is increasingly being used in the aerospace, marine, and land transport due to its lightweight, corrosion resistance, and high strength. However, hole drilling during assembly remains challenging due to extensive tool wear and delamination. Laser processing, typically used for drilling and machining, often produces heat effects or is low in efficiency if ultrashort pulse lasers are used. Here, we report an optimised result for a tailored sequence multiple-ring scanning laser drilling method that significantly improves the process efficiency (up to 800 %) by using a continuous wave high power fibre laser operating in pulse mode. Factors such as ring numbers, ring spacing (hatch distance), laser power, and pulse frequency are investigated using statistical design of experiments, and their interactions and effects on process efficiency, carbon emissions, heat-affected zone size, and hole taper are evaluated. The work shows that process efficiency can be significantly increased as the number of rings increases. This is counter-intuitive and would be useful for industrial applications. Using nitrogen as the assist gas results in significantly lower unit process carbon emissions than using argon. The mechanisms behind this efficiency improvement are discussed.

Neutrosophic Topological Vector Spaces and its Properties

The algebraic structures Group, Ring, Field and Vector spaces are important innovations in Mathematics. Most of the theoretical concepts of Mathematics are based on the theorems related to these algebraic structures. Initially many mathematicians developed theorems related to all these algebraic structures. In 20th century most of the researchers introduced the theorems on the algebraic structures with Fuzzy and Intuitionistic fuzzy sets. Recently in 21st century the researchers concentrated on Neutrosophic sets and introduced the algebraic structures like Neutrosophic Group, Neutrosophic Ring, Neutrosophic Field, Neutrosophic Vector spaces and Neutrosophic Linear Transformation. In the current scenario of relating the spaces with the structures, we have introduced the concepts of Neutrosophic topological vector spaces. In this article, the study of Neutrosophic Topological vector spaces has been initiated. Some basic definitions and properties of classical vector spaces are generalized in Neutrosophic environment over a Neutrosophic field with continuous functions. Neutrosophic linear transformations and their properties are also included in Neutrosophic Topological Vector spaces. This article is an extension work of fuzzy and intuitionistic fuzzy vector spaces which were introduced in fuzzy and intuitionistic fuzzy environments. Even though it is an extension work, Neutrosophic Topological Vector space will play an important role in Neural Networks, Image Processing, Machine Learning and Artificial Intelligence Algorithms.