Similar Solution Structures Research Articles

Factors affecting the final solution of the bike-sharing rebalancing problem under heuristic algorithms

The bike-sharing rebalancing problem (BRP) belongs to a class of one-commodity pickup and delivery vehicle route problems (1-PDVRPs) which often must be solved using heuristic algorithms due to the large problem size. However, an open question is which factors affect the quality of the final solutions for the BRP with heuristic algorithms, and how they affect the solution quality. This study proposed six initial solution construction methods and two heuristic algorithms, and applied 32 instances to explore this question in greater depth. The results showed that problem size and the algorithms' searching capacity are the most important factors affecting the quality of final solutions. Furthermore, the influence of the quality and diversity of initial solutions cannot be ignored. The quality of final solutions is negatively correlated with problem size, and positively correlated with the algorithms' searching capacity, and the quality and diversity of initial solutions. The influence of the quality and diversity of initial solutions on the quality of final solutions is positively correlated with problem size. For algorithms with insufficient (powerful) searching capacity, the influence of the quality (diversity) of initial solutions is more significant than that of their diversity (quality). High-quality and rich-diversity initial solutions are very helpful for algorithms to find high-quality final solutions. In addition, the CPU time of heuristic algorithms is generally positively correlated with their searching capacity. These findings have certain universal applicability and reference value for solving the 1-PDVRPs with similar solution structures using heuristic algorithms.

Does Salt Concentration Matter? New Insights on the Intercalation Behavior of PF6−${\rm{PF}}_6^ - $ into Graphite Cathode for the Dual‐Ion Battery

AbstractA high‐concentration electrolyte is favored in dual‐ion batteries (DIBs) due to the lower onset potential for anion intercalation, higher specific discharge capacity, and better oxidation stability. Inspired by the correlation between the high‐concentration electrolytes and localized high‐concentration electrolytes, it is suspected that it is not the salt concentration but the solution structure of the electrolyte that determines the intercalation behavior of anion into graphite cathode. To prove the viewpoint, a series of electrolytes are prepared by controlling the salt concentration or solution structure and the intercalation behavior of within the graphite cathode is investigated in Li||graphite and graphite||graphite cells. It is found that anions exhibit similar onset potentials and specific discharge capacities in the electrolytes with different salt concentrations but similar solution structures. This study provides a new perspective on designing promising electrolytes for DIBs, which can accelerate the further exploitation of high‐performance DIBs.

Backbone resonance assignments of the A2 domain of mouse von Willebrand factor.

von Willebrand factor (vWF) is an adhesive plasma protein that is important for platelet adhesion in normal hemostasis in response to vascular injury. Although large vWF multimers are released from storage granules of platelets and (sub-)endothelial cells in response to hemostatic stimuli, for normal physiological function, vWF multimers are required to be cleaved into smaller multimeric forms. The plasma metalloproteinase ADAMTS13 specifically cleaves the peptide bond located in the middle of the A2 domain of vWF (vWF-A2), but the cleavage site is buried inside the structure of vWF and is difficult to access in the absence of elevated flow shear stress. On the other hand, in the presence of high vascular shear stress, the structure of vWF-A2 is supposed to be unfolded, thereby becoming accessible for proteolysis by ADAMTS13. However, the atomic-level mechanism underlying shear-induced structural changes of vWF-A2 remains unclear and to date no solution NMR information is available. In this study, we present the backbone 1H, 13C, and 15N resonance assignments of mouse vWF-A2; side chain assignments of 13Cβ are also provided. Secondary structure propensity analysis based on the assigned chemical shifts showed that mouse vWF-A2 forms similar secondary structures in solution to the previously determined crystal structure of human vWF-A2. The obtained NMR assignment data will contribute to an atomic-level characterization of shear-induced unfolding of vWF-A2 in solution.

A multi-objective vibration damping optimization algorithm for solving a cellular manufacturing system with manpower and tool allocation

In this paper,a novel bi-objectivemathematical model is proposed to designa four-dimensional (i.e.,part, machine, operator, and tool) cellular manufacturing system (CMS) in a dynamic environment. The main objectives of this model are to 1) minimize total costs including tools processing cost, costs of transporting cells between various cells, machine setup cost, and operators’ educational costs, and 2) maximizing skill level of operators. The developedmodel is strictly NP-hard and exact algorithms cannot find globally optimal solutions in reasonably computational time. So, a multi-objective vibration damping optimization algorithm (MOVDO) with a new solution structure that satisfies all the constraints and generates feasible solutions is proposed to find near-optimal solutions in reasonablycomputational time. Since there is no benchmark available inthe literature, three other meta-heuristic algorithms (i.e., non-dominated sorting genetic algorithm (NSGA-II), multi-objective particle swarm optimization (MOPSO) and multi-objective invasive weeds optimization (MOIWO)) with the similar solution structure are developed to validate theperformance of the proposedMOVDOalgorithm for solving various instances of the developed model. A Taguchi method is employed to calibrate the main parameters ofthese fouralgorithms. The result of comparing theirperformances based on statistical tests and different measuring metrics reveals that theproposed MOVDO algorithm outperforms remarkably better than other meta-heuristics used in this paper.

超几何方程的一类非齐次边值问题解的相似结构

超几何方程的一类非齐次边值问题解的相似结构

Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis

The bis-ortho-thioether 9,10-bis[(o-methylthio)phenyl]anthracene was synthesized as a syn-atropisomer, as revealed by X-ray diffraction. This alkylaryl thioether ligand (L) formed different macrocyclic complexes by coordination with silver(I) salts depending on the nature of the anion: M2L2 for AgOTf and AgOTFA, M6L4 for AgNO3. A discrete M2L complex was obtained in the presence of bulky PPh3AgOTf. These silver(I) complexes adopted similar structures in solution and in the solid state. As each sulfur atom in the ligand is prochiral, macrocycles L2M2 were obtained as mixtures of diastereoisomers, depending on the configurations of the sulfur atoms coordinated to silver cations. The X-ray structures of the two L2·(AgOTf)2 stereoisomers highlighted their different geometry. The catalytic activity of all silver(I) complexes was effective under homogeneous conditions in two tandem addition/cycloisomerization of alkynes using 0.5–1 mol % of catalytic loading.

Long non‐coding subgenomic flavivirus RNAs have extended 3D structures and are flexible in solution

Most mosquito‐borne flaviviruses, including Zika virus (ZIKV), Dengue virus (DENV), and West Nile virus (WNV), produce long non‐coding subgenomic RNAs (sfRNAs) in infected cells that link to pathogenicity and immune evasion. Until now, the structural characterization of these lncRNAs remains limited. Here, we studied the 3D structures of individual and combined subdomains of sfRNAs, and visualized the accessible 3D conformational spaces of complete sfRNAs from DENV2, ZIKV, and WNV by small angle X‐ray scattering (SAXS) and computational modeling. The individual xrRNA1s and xrRNA2s adopt similar structures in solution as the crystal structure of ZIKV xrRNA1, and all xrRNA1‐2s form compact structures with reduced flexibility. While the DB12 of DENV2 is extended, the DB12s of ZIKV and WNV are compact due to the formation of intertwined double pseudoknots. All 3′ stem‐loops (3′SLs) share similar rod‐like structures. Complete sfRNAs are extended and sample a large conformational space in solution. Our work not only provides structural insight into the function of flavivirus sfRNAs, but also highlights strategies of visualizing other lncRNAs in solution by SAXS and computational methods.

NMR investigations on H2A-H2B heterodimer dynamics conferred by histone variant H2A.Z

H2A.Z, a highly conserved histone H2A variant in eukaryotes, plays critical roles in multiple nuclear events. H2A.Z forms a heterodimer with H2B when incorporated into nucleosomes. The heterodimer dynamics has been implicated in H2A.Z functions. To gain insights into H2A.Z dynamics, we analyzed yeast H2A.Z-H2B dimer (ZB) and yeast H2A-H2B dimer (AB) using solution NMR spectroscopy. First, we measured the 1H–15N heteronuclear NOE ratio of ZB and showed that the H2A.Z αC-helix region (residues 100–118) undergoes less structure fluctuation than its H2A counterpart. Strikingly, substituting H2A residues G99N100V101 with H2A.Z counterparts R106A107 reduced the fluctuation of H2A αC-helix, suggesting that H2A.Z dynamics play an important role in αC-helix extension and H2A.Z-chaperones recognition. We next measured the hydrogen-deuterium exchange (HX) rate of ZB and verified that the H2A.Z α2 helix and H2B α2, α3 helices are mostly protected. Notably, we observed nearly identical HX profiles for dimerized ZB and AB, suggesting that they have similar solution structures and dynamic characters. Together, our study gains first insight into H2A.Z-H2B dimer dynamics and sheds light on how its dynamics affect the structure and function of H2A.Z variant.

Workload equity in vehicle routing: The impact of alternative workload resources

In practical vehicle routing problems (VRPs), important non-monetary benefits can be achieved with more balanced operational plans that explicitly consider workload equity. This has motivated practitioners to include a wide variety of balancing criteria in decision support systems, and researchers to examine the properties of these criteria and the trade-offs made when optimizing them. As a result, previous studies have provided a much-needed understanding of how different equity functions affect the resulting VRP solutions. However, by focusing exclusively on models that balance tour lengths, a critical aspect has thus far remained unexplored — namely the impact of the workload resource subject to the balancing.In this work, we generalize previous studies to different workload resources, extend the scope of those analyses to additional aspects of managerial and methodological significance, and reevaluate accordingly previous conclusions and guidelines for formulating a balance criterion.Overall, our study counter-balances the focus of previous works and reveals the importance of selecting the right workload resource. Although the marginal cost of equity is low for all the examined models, the trade-off structure depends primarily on the workload resource, and less on the equity function. For the same resource, we observe a notable degree of overlap between the solutions found with different equity functions. Moreover, we find that there typically exists a set of low-cost VRP solutions that are well-balanced on average with respect to all the examined balance criteria. However, they are difficult to identify in practice as they are mostly Pareto-dominated by solutions optimized with respect to any single criterion. Finally, we observe that solutions with similar cost and balance tend to exhibit similar solution structure, a property that should be directly exploited by optimization methods.

Small Structural Changes in the Alkyl Substituents of Macrocyclic π-Extended Thiophene Oligomers Causes a Key Effect on Their Stacking and Functional Properties.

Three new macrocyclic π-extended thiophene hexamers composed of four thienylene-ethynylene and two thienylene-vinylene units with or without four alkyl substituents have been synthesized. Despite similar shape-persistent structures in solution, the alkyl substituents control the solid-state structures and morphologies. The unsubstituted hexamer exhibited a planar conformation with a theoretically predicted structure in the solid state; however, the planar hexamer with four ethyl substituents formed a closely stacked columnar crystal structure to exhibit π-π interactions. Interestingly, the hexamer with four butyl substituents adopted both planar and twisted conformations in the solid state, exhibiting polymorphism based on induced-fit stacking of molecules. Thus, the butyl-substituted hexamer produces a mixture of yellow, orange, and red single crystals from toluene/acetone, and X-ray analysis revealed six different conformations. Consequently, the small structural difference in the macrocycles causes a key effect on their functional properties in the solid state, and their morphology governs electrical conductivity and organic field-effect-transistor activity. The polymorphism of the hexamers was applied to the switching of film morphology.

Structures and anti-inflammatory properties of 4-halogenated -mofebutazones

The crystal structures of the 4-halogenated (hal: F, Cl, Br)-4-butyl-1-phenyl-1,3-pyrolidine-dione (mofebutazone) are determined, and compared with their solution structures. The racemic 4-halogenated mofebutazone approximants crystallize in a monoclinic space group with four molecules in the unit cell. The 4-hal-mofebutazone molecules reveal strong hydrogen bonding between the hydrogen atom located at the N-2 nitrogen atom and a carbonyl oxygen atom of an adjacent 4-hal-mofebutazone molecule. The hydrogen bond angle for 4-Br-mifebutazone N (2)H (1)⋯O (1) is 173(3) °, so that the hydrogen bond is essentially linear indicating an infinite chain hydrogen bond network. The 3d and 2d structures are stabilized by π-π and σ-π interactions, short intermolecular distances, and apolar forces between adjacently stacked phenyl rings. Small-angle-X-ray scattering (SAXS) experiments and osmometric measurements reveal the presence of dimers for the 4-hal-mofebutazone molecules. Molecular simulations indicate similar solution structure factors for the 4-hal-mofebutazones solutions, S(Q), and in the solid state. There is a strong indication that the [1,1,0], [1,0,0], and [1,0,0] periodicities of the 4-Br, 4-Cl and 4-F-mofebutazone in the crystalline solid state were also present in the solution phase. The biochemical and cellular activities of the different 4-hal-mofebutazones were monitored by the magnitude of their inhibition of the PGE2 biosynthesis through the cyclo-oxygenase (COX-1) in macrophages, and on the inhibition of LTD4 (5-lipoxygenase) in polymorphonuclear leukocytes.

Similar Structure of Solution for the Model of Nonlinear Seepage in Multilayer Composite Reservoir

Similar Structure of Solution for the Model of Nonlinear Seepage in Multilayer Composite Reservoir

Investigating the Structural Compaction of Biomolecules Upon Transition to the Gas-Phase Using ESI-TWIMS-MS

Collision cross-section (CCS) measurements obtained from ion mobility spectrometry-mass spectrometry (IMS-MS) analyses often provide useful information concerning a protein’s size and shape and can be complemented by modeling procedures. However, there have been some concerns about the extent to which certain proteins maintain a native-like conformation during the gas-phase analysis, especially proteins with dynamic or extended regions. Here we have measured the CCSs of a range of biomolecules including non-globular proteins and RNAs of different sequence, size, and stability. Using traveling wave IMS-MS, we show that for the proteins studied, the measured CCS deviates significantly from predicted CCS values based upon currently available structures. The results presented indicate that these proteins collapse to different extents varying on their elongated structures upon transition into the gas-phase. Comparing two RNAs of similar mass but different solution structures, we show that these biomolecules may also be susceptible to gas-phase compaction. Together, the results suggest that caution is needed when predicting structural models based on CCS data for RNAs as well as proteins with non-globular folds.Graphical ᅟ

Similar structure of solution for triple media shale gas reservoir

In view of the limitations of the traditional shale gas reservoir model when used in describing the process of shale gas flow, this paper establishes the seepage model of a triple media shale gas reservoir, and takes the adsorption and desorption process into account. By combining the use of Laplace transforms with similar structure theory, pseudo pressure solutions under three different outer boundary conditions having similar structures are obtained in Laplace space. The pseudo pressures are then inverted into real space with the Stehfest numerical inversion logarithm. In addition, the characteristic curves are drawn, and impact of the variation of the main parameters on them are analyzed. The results show that three different outer boundary conditions of the pseudo pressures are only different at the kernel functions. Furthermore, under the similar structure theory, portraying the characteristic curves of three different outer boundary conditions only requires a change to the kernel functions. Therefore, the similar structure theory replaces the complex calculation process of seepage equations in the simple algebraic calculation. At the same time, the similar structure theory tremendously simplifies the drawing process of the characteristic curves. This will have a profound influence on the development of well testing analysis software in the future as well.

Synergy between Experimental and Computational Chemistry Reveals the Mechanism of Decomposition of Nickel-Ketene Complexes.

A series of (dppf)Ni(ketene) complexes were synthesized and fully characterized. In the solid state, the complexes possess η2-(C,O) coordination of the ketene in an overall planar configuration. They display similar structure in solution, except in some cases, the η2-(C,C) coordination mode is also detected. A combination of kinetic analysis and DFT calculations reveals the complexes undergo thermal decomposition by isomerization from η2-(C,O) to η2-(C,C) followed by scission of the C═C bond, which is usually rate limiting and results in an intermediate carbonyl carbene complex. Subsequent rearrangement of the carbene ligand is rate limiting for electron poor and sterically large ketenes, and results in a carbonyl alkene complex. The alkene readily dissociates, affording alkenes and (dppf)Ni(CO)2. Computational modeling of the decarbonylation pathway with partial phosphine dissociation reveals the barrier is reduced significantly, explaining the instability of ketene complexes with monodentate phosphines.

Similar Constructing Method for Solving the Boundary Value Problem of the Composite Thomson Equation

Based on the theory of similar structure of solution of the boundary value problem of differential equation, this paper studies the solution of a class of boundary value problem of the composite Thomson equation, After analysis? it is indicate that the solution with a form of continued fraction product is obtained by introducing functions of guide solution, constructing similar kernel functions and assembling coefficients of the left non-homogeneous boundary condition, functions of guide solution and similar kernel functions in this paper. Then a new method is obtained for solving the composite boundary value problem——Similar Constructive Method. Furthermore, the function solution is clearly illustrated by the chart which is carried out by the corresponding program in MTLAB. Thus, the method is not only simple and effective for solving the complicated boundary value problem of differential equation, but also is a kind of innovation of ideological.

Study on how to resolve the boundary value problem of three-region composite Thomson equation

On the basis of the theory in similar structure of solution of the boundary value problem for a differential equation, this paper studies the boundary value problem of a three-region composite, Thomson equation. Firstly, this paper obtains similar structure related to solution of the boundary value problem of a three-region composite Thomson equation. Secondly, this paper points out the steps and flow chart about the algorithm for solving the boundary value problem. Finally, this paper gives an application of the obtained steps and draws the solution curve of the boundary value problem by executing the program on the computer. The obtained steps mentioned in this paper are not only simple and effective to resolve the complicated boundary value problem of a differential equation, but also useful to acquire the analytical solution of the model of composite reservoir.

Conformational studies on peptides having dipropylglycine (Dpg) or 1-aminocycloheptanecarboxylic acid (Ac7 c) within the sequence of l-leucine (Leu) residues.

A conformational analysis of peptides having dipropylglycine (Dpg) or 1-aminocycloheptanecarboxylic acid (Ac7 c) within l-leucine (Leu) residues was conducted in solution and in a crystal state. Dpg and Ac7 c had similar structures with acyclic and cyclic side chains, respectively. FTIR, 1 H NMR, and CD spectra measurements revealed that the preferred conformations of Dpg- and Ac7 c-containing l-Leu peptides in solution were similar; both had a right-handed (P) 310 -helix. The Dpg-containing octapeptide adopted a right-handed (P) α-helix in the crystal state. Dpg and Ac7 c homopeptides had planar and helical structures as their preferred conformations, respectively; however, Dpg- and Ac7 c-containing l-Leu peptides adopted similar structures in solution. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 210-218, 2016.

Homoleptic transition metal complexes of the 7-azaindolide ligand featuring κ(1)-N1 coordination.

Homoleptic complexes of the anion of 7-azaindole (AzaIn) were synthesized and characterized for a series of 3d transition metals. For Mn(II), Fe(II), and Co(II), complexes of formula Na2[M(AzaIn)4]·2L (L = tetrahydrofuran (THF), 2-MeTHF, toluene, or benzene) were isolated by treatment of the corresponding metal chloride salts with 7-azaindole in the presence of sodium hexamethyldisilazide. The complexes adopt tetrahedral geometries with exclusive coordination to the transition metal ion through the pyrrolic N1 nitrogen atoms of the AzaIn ligands. Solid-state structures of the complexes demonstrate that the sodium cations remain tightly associated with the coordination entities through interaction with both the pyrrolic and pyridine nitrogen atoms of the azaindolide ligands. For Fe(II), replacement of the sodium cations by other alkali metal ions (Li or K) generates new complexes that demonstrate similar coordination geometries to the sodium salts. As a means of comparison, the Fe(II) complex of 4-azaindolide was also investigated. Na2[Fe(4-AzaIn)4]·2L adopts a similar solution structure to the 7-azaindolide complexes as judged by NMR spectroscopy and cyclic voltammetry. Density functional theory calculations were performed to investigate the bonding in the 7-azaindolide complexes. Results demonstrate that 7-azaindolide-κ(1)-N1 is a nearly pure sigma donor ligand that features a high degree of ionic character in its bonding to mid 3d transition metal ions.

Molecular Simulation of Structure and Diffusion at Smectite–Water Interfaces: Using Expanded Clay Interlayers as Model Nanopores

In geologic settings relevant to a number of extraction and potential sequestration processes, nanopores bounded by clay mineral surfaces play a critical role in the transport of aqueous species. Solution structure and dynamics at clay–water interfaces are quite different from their bulk values, and the spatial extent of this disruption remains a topic of current interest. We have used molecular dynamics simulations to investigate the structure and diffusion of aqueous solutions in clay nanopores approximately 6 nm thick, comparing the effect of clay composition with model Na-hectorite and Na-montmorillonite surfaces. In addition to structural properties at the interface, water and ion diffusion coefficients were calculated within each aqueous layer at the interface, as well as in the central bulk-like region of the nanopore. The results show similar solution structure and diffusion properties at each surface, with subtle differences in sodium adsorption complexes and water structure in the first adsorbed...