Search

Grid is a free and open-source Python library for constructing numerical grids to integrate, interpolate, and differentiate functions (e.g., molecular properties), with a strong emphasis on facilitating these operations in computational chemistry and conceptual density functional theory. Although designed, maintained, and released as a stand-alone Python library, Grid was originally developed for molecular integration, interpolation, and solving the Poisson equation in the HORTON and ChemTools packages. Grid is designed to be easy to use, extend, and maintain; this is why we use Python and adopt many principles of modern software development, including comprehensive documentation, extensive testing, continuous integration/delivery protocols, and package management. We leverage popular scientific packages, such as NumPy and SciPy, to ensure high efficiency and optimized performance in grid development. This article is the official release note of the Grid library showcasing its unique functionality and scope. [ABSTRACT FROM AUTHOR]

The numerical ill‐conditioning associated with approximating an electron density with a convex sum of Gaussian or Slater‐type functions is overcome by using the (extended) Kullback–Leibler divergence to measure the deviation between the target and approximate density. The optimized densities are non‐negative and normalized, and they are accurate enough to be used in applications related to molecular similarity, the topology of the electron density, and numerical molecular integration. This robust, efficient, and general approach can be used to fit any non‐negative normalized functions (e.g., the kinetic energy density and molecular electron density) to a convex sum of non‐negative basis functions. We present a fixed‐point iteration method for optimizing the Kullback–Leibler divergence and compare it to conventional gradient‐based optimization methods. These algorithms are released through the free and open‐source BFit package, which also includes a L2‐norm squared optimization routine applicable to any square‐integrable scalar function. [ABSTRACT FROM AUTHOR]

HORTON is a free and open-source electronic-structure package written primarily in Python 3 with some underlying C++ components. While HORTON's development has been mainly directed by the research interests of its leading contributing groups, it is designed to be easily modified, extended, and used by other developers of quantum chemistry methods or post-processing techniques. Most importantly, HORTON adheres to modern principles of software development, including modularity, readability, flexibility, comprehensive documentation, automatic testing, version control, and quality-assurance protocols. This article explains how the principles and structure of HORTON have evolved since we started developing it more than a decade ago. We review the features and functionality of the latest HORTON release (version 2.3) and discuss how HORTON is evolving to support electronic structure theory research for the next decade. [ABSTRACT FROM AUTHOR]

Interlocking of intramedullary nails is a challenging procedure in orthopedic trauma surgery. Numerous methods have been described to facilitate this process. But they are exposed patient and surgical team to X-rays or involves trial and error. An accurate and non-invasive method has been provided to easily interlocking intramedullary nails. By transferring a safe visible light inside the nail, a drilling position appears which use to drilling bone toward the nail hole. The wavelength of this light was obtained from ex-vivo spectroscopy on biological tissues which has optimal transmission, reflectance, and absorption properties. Moreover, animal and human experiments were performed to evaluate performance of the proposed system. Ex-vivo performance experiments were performed successfully on two groups of cow and sheep samples. Output parameters were procedure time and drilling quality which there were significant differences between the two groups in procedure time (P < 0.05). But no significant differences were observed in drilling quality (P > 0.05). Moreover, an In-vivo performance experiment was performed successfully on a middle-aged man. To compare the provided method, targeting-arm, and free-hand techniques, two human experiments were performed on a middle-aged and a young man. The results indicate the advantage of the proposed technique in the procedure time (P < 0.05), while the drilling quality is equal to the free-hand technique (P = 0.05). Intramedullary nail holes laser indicator is a safe and accurate method that reduced surgical time and simplifies the process. This new technology makes it easier to interlocking the intramedullary nail which can have good clinical applications. [ABSTRACT FROM AUTHOR]

A relatively simple experimental procedure is proposed for the simultaneous detection and quantitative assessment of moxifloxacin (Moxi) as an example for an antibiotic using surface‐enhanced Raman spectroscopy (SERS) performed in a Kretschmann configuration (KC). The example of Moxi shows the advantage of this approach, such as high sensitivity and relatively simple experimental procedure. The Moxi was reliably detected at levels of 100 nM using excitation laser powers as low as a few milliwatts. We also demonstrate that in the KC, the direct coupling between the electronic systems of analyte molecules and metal substrate contributing to the chemical enhancement mechanism in SERS plays a major role. For this, we have performed simulations based on density functional theory (DFT). The line profile of the SERS spectra can be explained by the direct coupling of molecular sites to the metal. This adds to the molecular specificity of SERS when using the KC. [ABSTRACT FROM AUTHOR]

This paper will explore the restriction of the coherent information to the positive definite density matrices in the special case where the quantum channels are strictly positive linear maps. The space of positive definite density matrices is equipped with an embedded submanifold structure of the real vector space of Hermitian matrices. These ensure that the n-shot coherent information is differentiable and allows for the computation of its gradient and Hessian. We show that any tensor products of critical points preserve being a critical point of the coherent information. Furthermore, we show that for any positive integer n, the maximally mixed state is always a critical point for the class of mixed unitary quantum channels with orthogonal, unitary Kraus operators. We determine when the maximally mixed state is a local maximum/minimum or saddle point, including its eigenvectors, for the class of Pauli-erasure channels when n is equal to 1. This class includes the dephrasure channel and Pauli channel and refines potential regions where super-additivity is thought to occur. These techniques can be used to study other optimization problems over density matrices and allow the use of manifold optimization algorithms and a better understanding of the quantum capacity problem by utilizing the first and second order geometry. [ABSTRACT FROM AUTHOR]

We consider the nonlinear eigenvalue problem L u = λ f (u) , posed in a smooth bounded domain Ω ⊆ R N with Dirichlet boundary condition, where L is a uniformly elliptic second-order linear differential operator, λ > 0 and f : [ 0 , a f) → R + (0 < a f ⩽ ∞) is a smooth, increasing and convex nonlinearity such that f (0) > 0 and which blows up at a f . First we present some upper and lower bounds for the extremal parameter λ ∗ and the extremal solution u ∗ . Then we apply the results to the operator L A = − Δ + A c (x) with A > 0 and c (x) is a divergence-free flow in Ω. We show that, if ψ A , Ω is the maximum of the solution ψ A (x) of the equation L A u = 1 in Ω with Dirichlet boundary condition, then for any incompressible flow c (x) we have, ψ A , Ω ⟶ 0 as A ⟶ ∞ if and only if c (x) has no non-zero first integrals in H 0 1 (Ω). Also, taking c (x) = − x ρ (| x |) where ρ is a smooth real function on [ 0 , 1 ] then c (x) is never divergence-free in unit ball B ⊂ R N , but our results completely determine the behaviour of the extremal parameter λ A ∗ as A ⟶ ∞. [ABSTRACT FROM AUTHOR]

Light-weight high-strength composites (particularly with aluminum and magnesium base alloys) have principal applications in a wide variety of fields ranging from automotive and aerospace structures to medical and energy applications wherein the materials undergo both static and dynamic (fatigue) loading conditions. Conventional metal matrix composites (MMCs), i.e. those filled by micro-sized reinforcements, have usually poor ductility and insufficient mechanical performance made them, therefore, unreliable to be used in some critical applications. Instead, those composites strengthened by nano-sized reinforcing agents, namely metal matrix nano-composites (MMNCs), have newly been developed in order to boost the mechanical properties. The current paper aims to study the fatigue behavior of the MMCs with a particular attention on recent investigations made on MMNCs. It is believed that the materials selection, microstructural features, manufacturing and processing parameters, etc. have a dominant influence on the fatigue response of MMNCs. [ABSTRACT FROM AUTHOR]

Let G = (V;E) be a graph. We say that S ⊆ V is a defensive alliance if for every u ∈ S, the number of neighbors u has in S plus one (counting u) is at least as large as the number of neighbors it has outside S. Then, for every vertex u in a defensive alliance S, any attack on a single vertex by the neighbors of u in V - S can be thwarted by the neighbors of u in S and u itself. In this paper, we study alliances that are containing a given vertex u and study their mathematical properties. [ABSTRACT FROM AUTHOR]

Abstract This paper explains the crystal structure analysis of Ag(I) coordination polymers based on 4-Amino-3-halobenzonitrile ligands. Three coordination polymers of general formula [Ag(L x)]NO 3 , where X = Cl(1), I(3) and [Ag 2 (L x)][NO 3 ] 2 , where X = Br(2), were synthesized and characterized by single crystal X-ray crystallography. The effect of changing the single halogen atom of 4-Amino-3-halobenzonitrile on the crystal packing of a series of Ag(I) coordination polymers was studied. Our results revealed that N-H···O hydrogen bonds play important role in the crystal packing. Nanoparticles of these coordination polymers were also synthesized by ultrasonic irradiation of (1) , (2) and (3) , and characterized using different analytical techniques. Graphical abstract In this paper, we investigated the synthesis and characterization of three new Silver (I) coordination polymers containing 4-Amino-3- halobenzonitrile ligands with different halogen substituents. Herein, Compounds 1, 2 and 3 were synthesized by reaction of AgNO3 with LCl, LBr and LI respectively. These compounds are completely characterized by the elemental analysis, FT-IR spectroscopy and single crystal X-ray crystallography. fx1 [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Compound 1 , [Cd(L1)(DMF) 3 ], as urea-functionalized MOF was synthesized. • Effects of sonication time, sonication power and initial concentration have been investigated. • High concentrations of initial reagents increased particles size of compound 1. • Low concentrations of initial reagents leaded to nanostructures. Abstract Dramatic advances in nanostructured MOFs have been strongly promoted by the introduction and development of new synthetic methods that control the size, morphology, and nano/microstructure. High intensity ultrasound method suggests an environmentally friendly, facile and versatile synthetic method to these nanostructured materials that are complicated to synthesize by commonly used methods. Both Solvothermal and sonochemical methods were used to synthesize the new urea-based metal-organic framework [Cd(L1)(DMF) 3 ] (1). Compound 1 was structurally characterized by using X-ray crystallography and spectroscopically by different techniques. The effect of concentration of the initial reagents, time of sonication and sonication power on size and morphology has been studied. The results indicate that decreasing concentration of initial reagents, along with increasing ultrasonic radiation time, cause a dramatic effect on the size and morphology of compound 1. Calcination of the nano-sized plate-like particles of compound 1 at 550 °C under air atmosphere yields CdO nanoparticles. [ABSTRACT FROM AUTHOR]

Chemical sensors for the rapid and selective detection of explosives such as 2,4,6-trinitrotoluene (TNT) are very important. In order to find efficient sensors with enhanced performance for nitro-aromatics, a series of IRMOFs with different pillaring ligands but the same network topology was examined. The fluorescence sensing ability of these compounds towards nitrobenzene (NB), 1,3-dinitrobenzene (1,3-DNB), 2,4-dinitrotoluene (2,4-DNT) and 2,4,6-trinitrotoluene (TNT) was investigated. These compounds have great potential for the detection of TNT. The limit of detection (LOD) for TNT is 112, 261, 833 and 1070 nM for TMU-6(L1), TMU-21(L2), TMU-6(RL1) and TMU-21(RL2), respectively. The LOD of TMU-21(RL2) is among the highest values reported in the literature for sensing TNT. The results highlight both the importance of functionality on the pillaring ligands as well as the hydrophilic/hydrophobic nature of the framework pores for the potential of MOFs for the detection of nitro-aromatics. [ABSTRACT FROM AUTHOR]

Two urea-containing MOFs, namely TMU-35 and TMU-36, were synthesized and characterized using X-ray crystallography and different spectroscopic techniques. Since these compounds contain urea functional group, they can interact favorably through hydrogen bonding with carbonyl compounds and thus they are potential candidates for carbonyl compounds sensing. Our study reveals that, when the pillaring linker containing benzene core (TMU-35) is replaced by pillaring linker containing naphthalene core (TMU-36), fluorescence sensing ability towards carbonyl compounds is dramatically quenched. It can be concluded that in comparison with TMU-35, TMU-36 provides a more electron-rich and hydrophobic pore walls which can interact favorably with organic analytes. This result is interesting as it represents the first example of the application of functionalized MOFs for carbonyl compounds sensing. [ABSTRACT FROM AUTHOR]

Two pillared metal-organic frameworks containing urea functional groups were synthesized by a sonochemical method and characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analysis. The time of sonication and concentration of starting materials have been optimized to synthesize nanoparticles of TMU-31 and TMU-32. These two frameworks are interesting candidates for a comparative fluorescence study. Thus, their potential abilities for phenol sensing were investigated. This investigation revealed the prominent roles of hydrogen bond donating urea groups inside the pore cavity in the ability of these structures in phenol sensing. [ABSTRACT FROM AUTHOR]

Chalcogen bonding interactions have earned an important recognition as prominent driving forces in fields such as supramolecular chemistry and crystal engineering. Herein, three Hg(ii) coordination polymers containing bis(4-pyridyl)disulfide were synthesized and characterized by X-ray crystallography and spectroscopic techniques. The crystal packing of these compounds was analyzed using different geometrical, statistical and theoretical analyses. A dual behavior of the S atom is observed in these compounds, since it is able to act as a Lewis acid in S…X chalcogen bonding and also participate in lp…π interactions as an electron donor. [ABSTRACT FROM AUTHOR]

We derive a priori bounds for positive supersolutions of -Δpu = ρ(x)f(u), where p > 1 and Δp is the p-Laplace operator, in a smooth bounded domain of RN with zero Dirichlet boundary conditions. We apply our results to the nonlinear elliptic eigenvalue problem -Δpu = λf(u), Dirichlet boundary condition, where f is a nondecreasing continuous differentiable function on such that f(0) > 0, f(t)¹=(p-1) is superlinear at infinity, and give sharp upper and lower bounds for the extremal parameter λ*p. In particular, we consider the nonlinearities f(u) = eu and f(u) = (1 + u)m (m > p - 1) and give explicit estimates on λ*p. As a by-product of our results, we obtain a lower bound for the principal eigenvalue of the p-Laplacian that improves obtained results in the recent literature for some range of p and N. [ABSTRACT FROM AUTHOR]

The urea group is a widely used functional group in anion recognition, owing to its ability to interact effectively with anions via formation of chelate hydrogen bonds. Previous solution state study shows that the presence of halogen substituents at ortho-positions to the urea moiety strongly enhances intermolecular hydrogen bonding interactions. In order to investigate the effect of the presence of ortho-halogen substituents on hydrogen bonding of aromatic ureas in the context of metallosupramolecular chemistry, three Ag(I) coordination polymers were synthesized and characterized by different techniques. The nitrate binding and the supramolecular organization in these compounds were studied by different geometrical and theoretical calculations. Based on this study, we can conclude that, as expected, the N-H···O hydrogen bond plays a key role in nitrate binding for this type of ligands, while weak C-X···O halogen bonds assist the anion binding to the receptor. In order to investigate the effect of the presence of ortho-halogen substituents on hydrogen bonding of aromatic ureas in metallosupramolecular chemistry, three Ag(I) coordination polymers were synthesized. It concluded that, as expected, the N-H···O hydrogen bond plays a key role in nitrate binding, while weak C-X···O halogen bonds assist the anion binding to the receptor. [ABSTRACT FROM AUTHOR]

Using a Kretschmann configuration-based setup, surface-enhanced Raman scattering (SERS) experiments have been performed on a monolayer of Nile blue. The experiment has been optimized to achieve reproducible conditions. Laser excitation resulted in a fast decay of the Raman line intensities ending at a stable signal level. We have analyzed this intensity variation mode specifically. The Raman deactivation rate was found to be different for different vibrational modes where high-wavenumber vibrations showed slower decay than the group of low-wavenumber modes. SERS spectra were obtained excluding the contribution of this deactivation process for different angles of incidence of the exciting laser beam. The variation of the surface plasmon excitation in the thin silver film coated onto the prism surface of the Kretschmann configuration resulted in drastically different relative enhancements of the different Raman modes pointing to a major contribution of the chemical enhancement mechanism in the single-layer SERS experiment. The enhancement was found to be mode-specific. High-wavenumber modes showed a stronger enhancement than the low-wavenumber group. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Due to the structural diversity of metal–organic frameworks, MOFs, tailored engineering of these compounds is important for their use in catalytic processes. Among the MOFs tested as heterogeneous catalysts, there have been rare reports of size selective catalysts. In the present work, we could successfully indicate that subtle substrate selectivity can be induced in the catalytic system by designing a series of isoreticular MOFs with slight structural modifications. Four MOF catalysts possessing imine and/or amine basic N-donor pillars bearing phenyl or naphtyl cores showing different hydrophobic characters around the basic reaction center were prepared via a simple mechano-chemical synthesis. They were characterized thoroughly using TG, IR and PXRD analysis. For the first time, the aldol-type condensation reaction of malononitrile with ketone-functionalized carbonyl substrates was developed in the presence of the basic MOF organocatalysts. Moreover, it has been successfully shown that a subtle substrate selectivity can be addressed during the reaction of three slightly different α,β-unsaturated carbonyl compounds in contrast to the effect of size control barriers that commonly direct a heterogeneous reaction pathway. [ABSTRACT FROM AUTHOR]

Four microporous lanthanide metal–organic frameworks (MOFs), namely Ln(BTC)(H2O)(DMF)1.1 (Ln = Tb, Dy, Er and Yb, DMF = dimethylformamide, H3BTC = benzene-1,3,5-tricarboxylic acid), have been used for selective adsorption of Pb(ii) and Cu(ii). Among these MOFs, the Dy-based MOF shows better adsorption property and selectivity toward Pb(ii) and Cu(ii) ions. Adsorption isotherms indicate that sorption of Pb(ii) and Cu(ii) on MOFs is via monolayer coverage. Preconcentration is based on solid-phase extraction in which MOFs were rapidly injected into water samples and adsorption of metal ions was rapid because of good contact with analyte; then adsorbed Pb(ii) and Cu(ii) ions were analyzed by FAAS. The optimized methodology represents good linearity between 1 and 120 μg L−1 and detection limit of 0.4 and 0.26 μg L−1 for Pb(ii) and Cu(ii), respectively. Subsequently the method was evaluated for preconcentration of target metal ions in some environmental water samples. [ABSTRACT FROM AUTHOR]

Two new pillared zinc and cadmium–organic frameworks were synthesized by incorporating two different organic linkers, namely 2-aminoterephthalic acid as an oxygen-donor linker and N4,N4′-bis(pyridin-4-ylmethylene)-biphenyl-4,4′-diamine as a long pillaring strut. The structures of these two frameworks were analyzed using X-ray crystallography, FT-IR spectroscopy, thermogravimetric and elemental analyses. Their structural features as well as their stability were studied. These two MOFs having the same organic composition and the same network topology but different inorganic nodes differ in their chemical stability. Also, these two frameworks respond differently to nitrobenzene when they are used as fluorescent sensors. Furthermore, the catalytic behavior of one of these frameworks toward the Knoevenagel condensation reaction was investigated. [ABSTRACT FROM AUTHOR]

Two new Hg(II) coordination polymers containing N , N ′-Bis-pyridin-3-ylmethylene-naphtalene-1,5-diamine ligand were synthesized by conventional and sonochemical methods, characterized by spectroscopic techniques (FT-IR and elemental analysis), and their X-ray crystallographic structures were determined. The crystal packing and supramolecular features of these coordination polymers were studied using geometrical analysis and Hirshfeld surface analysis. The crystal structure analysis revealed that H⋯H contacts, C–H⋯π and C–H⋯X (X = Cl for 1 and X = Br for 2 ) hydrogen bonding interactions are strong enough to govern the supramolecular architecture. The BFDH analysis helps us to compare the predicted morphology to that obtained under ultrasonication. This study may provide further insight into discovering the role of weak intermolecular interactions in the context of nano-supramolecular assembly. [ABSTRACT FROM AUTHOR]

In this paper, the Zn-based analogue of Cu 3 (btc) 2 (HKUST-1), Zn 3 (btc) 2 nanorods (Zn-HKUST-1; btc = 1,3,5-benzenetricarboxylate) have been synthesized through direct precipitation in solution phase under ultrasound condition without the assistance of any surfactant, catalyst, or template. Zn-HKUST-1 nanorods werecharacterized by Fourier transform infrared studies, elemental analysis, powder X-ray diffraction and field emission scanning electron microscopy. Concentration of initial reagent effects on size and morphology of the Zn-HKUST-1 has been studied and shows that low concentrations of initial reagents decreased widths, thicknesses, and lengths of nanorods. Subsequently, ligand-free ZnO nanorods and nanoparticles are selectively prepared via a thermal decomposition method using the corresponding nanorods and single crystals as a precursor, respectively. This solid-state transformation route is promising for the preparation of crystalline nanomaterials with desired morphologies because of its simplicity and the low cost of the starting reagents. [ABSTRACT FROM AUTHOR]

A series of eight new Hg(ii) complexes based on the L4-X ligands, where L is (E) -4-halo-N-(pyridin-4-ylmethylene)aniline, were synthesized and characterized and their supramolecular crystal structures were studied by different geometrical and theoretical methods. Our study reveals the role of weak intermolecular interactions involving halogens, such as C–H…X hydrogen bonds (in the cases of 1, 2, 3, 5, 6 and 7) and C–X…X′–M halogen bonds (in the cases of 4 and 8), in the structural changes of supramolecular assemblies of coordination compounds. Complexes 1–8 were also synthesized by sonochemical irradiation and the morphology of the prepared complexes was investigated using FE-SEM. The BFDH analysis helps us to compare the predicted morphology to that obtained under ultrasonication. This study may provide further insight into discovering the role of weak intermolecular interactions in the context of metallosupramolecular assembly. [ABSTRACT FROM AUTHOR]

An investigation has been made to combine ultrasonic vibration and wire electrical discharge turning. Design of a submerged, precise, flexible, and corrosion-resistant rotary spindle is introduced. The spindle was mounted on a five-axis wire electrical discharge machine to rotate the workpiece in order to generate free-form cylindrical geometries. An auxiliary device that produces ultrasonic vibration was installed between the two wire guides. The ultrasonic system consists of an ultrasonic generator, a transducer, and a wire holder. When the wire is being driven, the transducer together with the wire holder vibrates under the resonance condition. Material removal rate (MRR) indicates efficiency and cost-effectiveness of the process. Experimental results show that wire vibration induced by ultrasonic action has a significant effect on material removal rate. This study has been conducted to evaluate the influence of four design factors: power, pulse off time, spindle rotational speed, and ultrasonic vibration over material removal rate. This has been done by means of design of experiments technique. Analysis of variance was used to determine significant effective factors and also to obtain an equation based on data regression. Experimental results indicate that ultrasonic vibration and power are the most significant influencing parameters on MRR. Rotational speed and pulse off time are the next in ranking. In order to study surface roughness, R is measured in different machining parameters. [ABSTRACT FROM AUTHOR]

In the current work, some experiments were performed based on a design of experiment (DOE) technique called full factorial design. The experimental results are discussed in statistical analysis, and the system was modeled using the artificial neural network (ANN) and subsequently optimized by a genetic algorithm (GA). The statistical analysis shows that the main effects and some 2-interaction effects affect the surface roughness and flank wear. The results show that the feed rate, nose radius, and approach angle have a significant effect on the flank wear and the surface roughness, but the cutting velocity has a significant effect on the flank wear alone. The optimum values of cutting parameters were identified and the resultant optimum values of flank wear and surface roughness were found to be in good agreement with the results of a validation experiment under a similar condition. The optimized values showed a significant reduction in roughness and flank wear. [ABSTRACT FROM AUTHOR]

Two concomitant conformational polymorphs of N-(3-bromophenyl)-2-pyrazinecarboxamide have been discovered and characterized. The synthon crossover between Br…Br and Br…N “halogen bonding” on the formation of these polymorphs has been investigated by Hirshfeld surface analysis, halogen bonding interaction energy, lattice energy calculations and calorimetric analysis. From our results, it can be seen that different halogen bonding synthons, along with other intermolecular interactions, namely hydrogen bonding and π–π stacking interactions, result in the formation of different conformational polymorphs. [ABSTRACT FROM AUTHOR]

This study explores the feasibility of removing the recast layer formed on aluminum alloy cylindrical specimens machined by wire electrical discharge machining (WEDM) by using magnetic abrasive finishing (MAF). The WEDM is a thermal machining process capable of accurately machining parts with high hardness or complex shapes. The sparks produced during the WEDM process melt the metal's surface. The molten material undergoes ultra-rapid quenching and forms a layer on the surface defined as recast layer. The recast layer may be full of craters and microcracks which reduce service life of materials tremendously, especially under fatigue loads in corrosive environments. This investigation demonstrates that MAF process, can improve the quality of WEDM machined surfaces effectively by removing the recast layer. The present work studies the effect of some parameters, i.e., linear speed, working gap, abrasive particle size, and finishing time on surface roughness and recast layer thickness using full factorial analysis. Three-level full factorial technique is used as design of experiments for studying the selected factors. In order to indicate the significant factors, the analysis of variance has been used. In addition, an equation based on regression analysis is presented to indicate the relationship between surface roughness and recast layer thickness of cylindrical specimens and finishing parameters. Experimental results show the influence of MAF process on recast layer removal and surface roughness improvement. [ABSTRACT FROM AUTHOR]

In this study, iV-(3-halophenyl)-2-pyrazinecarboxamide ligands, L34', L0, L3Br, and L34, carrying a different halogen atom on the phenyl mía-posítion and N-phenyl-2-pyrazinecarboxamide ligand, LH, have been employed for the synthesis of 12 mercury(II) complexes, [HgCl2(LH)]„ 1, [HgCCL3)] 2, [HgCÍLJ, 3, [HgLJ, 4, [Hg2Br4(L»)J, S, [HgBr2(L>], 6, [HgBr2(L )], 7, [HgBr2(L)]. 8, [HgBr2(L* «)], 9, [Hg2I4(L")J, 10, [HgI2(L)], 11, and [HgJL3"1)]., 12. Interestingly, structural analysis dearly shows that, by the replacing of coordinated anions from chloride with bromide and iodide in each series containing the same ligand, the coordination geometry and structural motif of the resulting compounds have been dramatically affected. One of the common features in the crystal structures of these complexes is that there is a strong tendency to form halogen bonding synthons between adjacent halophenyl and pyrazine rings. The influence of these halogen bonding interactions on the supramolecular assemblies has been discussed with the help of geometrical analysis and theoretical calculations. The X--N halogen bonding distances are 23--9-4% shorter than the sum of the van der Waals radii of nitrogen and halogen atoms. Theoretical methods also show the halogen bonding energies within a range of --27.86 to --46.15 KJ-mol . In all complexes synthesized here, the pyrazine ring is coordinated to the mercury(LL) ion through the N atom JJU to the carbonyl. Therefore, the second common feature of the crystal structures for complexes studied here is the selectivity of the metal ion coordination site. The halogen bond synthon repetitivity across these compounds and selectivity m the meroiry{ll) ion coordination site further point to application in the coordination crystal engineering research field. [ABSTRACT FROM AUTHOR]

Recent needs to superfinished surfaces have motivated researchers to study on modern methods of polishing. Magnetic-assisted finishing is one of those methods which can generate mirror-like finished surfaces. This paper investigates the effects of some parameters, i.e., rotational speed of the permanent magnetic pole, working gap between the permanent pole and the workpiece, number of cycles, and the weight of the abrasive particles on aluminum surface finishing. Three-level full factorial method was used as design of experiments technique to study the selected factors. A total of 54 designed tests were done on aluminum sheet using an innovative material removal mechanism. Analysis of variance was used to determine significant factors and also to obtain an equation based on data regression. Experimental results indicate that the number of cycles and working gap are the most significant parameters on surface roughness change (∆Ra), followed by rotational speed and then weight of powder. [ABSTRACT FROM AUTHOR]

Abstract: Iron and manganese complexes meso-tetraphenylporpholactone, MTPPLX, and meso-tetraphenyl-2,3-dihydroxy-2,3-chlorin, MTPP(OH)2X (X=Cl and (CH3COO)), are efficient catalysts for selective oxidation of sulfides with hydrogen peroxide. The effect of catalyst concentration on the conversion, selectivity and yield of products were studied. The results show that iron and manganese porpholactones and chlorins are a slightly better catalyst than TPP analogues for most sulfide substrates. [Copyright &y& Elsevier]

In this paper, the effects and the optimization of machining parameters on surface roughness and roundness in the turning wire electrical discharge machining (TWEDM) process are investigated. In the TWEDM process, a new machining parameter, such as rotational speed, is introduced, which changes the normal machining conditions in conventional wire electrical discharge machining (WEDM). By the Taguchi method, a complete realization of the process parameters and their effects were achieved. The Taguchi method has not been used in TWEDM by other researchers. The surface roughness and roundness were measured to verify the process. In addition, the open-circuit voltage, pulse-off time, open arc voltage, and the inter-electrode gap size, which are replaced by power, time-off, voltage, and servo, respectively, and also wire tension, wire speed, and rotational speed were chosen for evaluation by the Taguchi method. An L18 (21 × 37) Taguchi standard orthogonal array was chosen for the design of experiments. The level of importance of the machining parameters on the surface roughness and roundness was determined by using analysis of variance (ANOVA). The optimum machining parameters combination was obtained by using the analysis of signal-to-noise (S/N) ratios. The variation of surface roughness and roundness with machining parameters was mathematically modeled by using the regression analysis method. Finally, experimentation was carried out to identify the effectiveness of the proposed method. The presented model is also verified by a set of verification tests. [ABSTRACT FROM AUTHOR]

Abstract: The application of wire electrical discharge machining (WEDM) for machining of precise cylindrical forms on hard and difficult-to-machine materials is presented. At first, the design of a precise, flexible and corrosion-resistant rotary spindle submerged is introduced. The spindle has been mounted on a five-axis wire EDM machine to rotate the workpiece in order to generate free form cylindrical geometries. The material removal rate (MRR) is an important indicator of the efficiency and cost-effectiveness of the process. Several experiments are conducted to consider effects of power, time-off, voltage, servo, wire speed, wire tension, and rotational speed (factors) on the MRR (response). An L18 (21 ×37) Taguchi standard orthogonal array is chosen for the design of experiments. Analyses of variance (ANOVA) as well as regression analysis are performed on experimental data. The signal-to-noise (S/N) ratio analysis is employed to find the optimal condition. [Copyright &y& Elsevier]

Abstract: In this work, a surface roughness (Ra), roundness and material removal rate (MRR) study on the cylindrical wire electrical discharge turning (CWEDT) has been carried out. The material chosen in this case was AISI D3 tool steel due to its growing range of applications in the field of manufacturing tools, dies and molds as punch, tapping, reaming and so on in cylindrical forms. This study was made only for the finishing stages and has been carried out on the influence of four design factors: power, voltage, pulse off time and spindle rotational speed, over the three previous mentioned response variables. This has been done by means of the technique of design of experiments (DOE), which allows us to carry out the above-mentioned analysis performing a relatively small number of experiments. In this case, a 22 ×32 mixed full factorial design, has been selected considering the number of factors used in the present study. The resolution of this factorial design allows us to estimate all the main effects, factor interactions and pure quadratic effects of the four design factors selected to perform this study. For MRR, Ra and roundness regression models have been developed by using the response surface methodology (RSM). [Copyright &y& Elsevier]

Biomechanical attributes have emerged as novel markers, providing a reliable means to characterize cellular and subcellular fractions. Numerous studies have identified correlations between these factors and patients' medical status. However, the absence of a thorough overview impedes their applicability in contemporary state-of-the-art therapeutic strategies. In this context, we provide a comprehensive analysis of the dimensions, configuration, rigidity, density, and electrical characteristics of normal and abnormal circulating cells. Subsequently, the discussion broadens to encompass subcellular bioparticles, such as extracellular vesicles (EVs) enriched either from blood cells or other tissues. Notably, cell sizes vary significantly, from 2 μm for platelets to 25 μm for circulating tumor cells (CTCs), enabling the development of size-based separation techniques, such as microfiltration, for specific diagnostic and therapeutic applications. Although cellular density is relatively constant among different circulating bioparticles, it allows for reliable density gradient centrifugation to isolate cells without altering their native state. Additionally, variations in EV surface charges (-6.3 to -45 mV) offer opportunities for electrophoretic and electrostatic separation methods. The distinctive mechanical properties of abnormal cells, compared to their normal counterparts, present an exceptional opportunity for diverse medical and biotechnological approaches. This review also aims to provide a holistic view of the current understanding of popular techniques in this domain that transcend conventional boundaries, focusing on early harvesting of malignant cells from body fluids, designing effective therapeutic options, cell targeting, and resonating with tissue and genetic engineering principles. This review provides a comprehensive and clear overview of the size/shape, stiffness, density, and electrical properties of circulating cellular/noncellular [ABSTRACT FROM AUTHOR]

BACKGROUND: Idiopathic granulomatous mastitis (IGM) is mostly described as an autoimmune disease with higher prevalence among Middle Eastern childbearing-age women. This study aimed to evaluate the best treatment of choice in patients with resistant or recurrent IGM. STUDY DESIGN: Patients with established recurrent or resistant IGM who were referred to the Breast Cancer Research Center from 2017 to 2020 were randomly assigned to either one of the following treatment groups: A (best supportive care), B (corticosteroids: prednisolone), and C (methotrexate and low-dose corticosteroids). This adaptive clinical trial evaluated radiological and clinical responses, as well as the potential side effects, on a regular basis in each group, with patients followed up for a minimum of 2 years. RESULTS: A total of 318 participants, with a mean age of 33.52 ± 6.77 years, were divided into groups A (10 patients), B (78 patients), and C (230 patients). In group A, no therapeutic response was observed; group B exhibited a mixed response, with 14.1% experiencing complete or partial responses, 7.7% maintaining stability, and 78.2% experiencing disease progression. Accordingly, groups A and B were terminated due to inadequate response. In group C, 94.3% achieved complete response, 3% showed partial remission, and 2.7% had no response to therapy. Among the entire patient cohort, 11.6% tested positive for antinuclear antibodies, 3.5% for angiotensin-converting enzyme, and 12.3% for erythema nodosum. Notably, hypothyroidism was a prevalent condition among the patients, affecting 7.2% of the cohort. The incidence of common side effects was consistent across all groups. CONCLUSIONS: The most effective treatment option for patients with recurrent or resistant IGM is a combination therapy involving steroids and disease-modifying antirheumatic drugs such as methotrexate. [ABSTRACT FROM AUTHOR]

Effects of pillaring linkers length on the size-dependent catalytic activity of two isoreticular metal–organic frameworks toward the aldol-type condensation reaction between malononitrile and α,β-unsaturated carbonyl compound. The result shows that the selectively of TMU-52 toward different substrate was significantly higher than TMU-25. The structure–activity relationship plays the main role in the applicability of Metal-organic Frameworks (MOFs) in different areas including catalysis. Regarding to this herein a novel pillar-layered MOF (TMU-52) that is isostructural to our recently reported TMU-25 is introduced. The structure of this framework was analyzed using X-ray crystallography, FT-IR spectroscopy, Thermogravimetric and elemental analyses. According to the similar organic and inorganic backbone, a comparative study was done on catalytic manner of TMU-25 and TMU-52 toward in aldol-type condensation reaction. TMU-52 was designed through replacing the biphenyl core in the pillar linker of TMU-25 with phenyl group as a better candidate heterogeneous catalysis. The selectivity of the TMU-52 was higher owing to its narrower channels. CO 2 /N 2 affinity of these structures was also investigated. [ABSTRACT FROM AUTHOR]

• A new metal-organic framework (decorated with methyl and amine groups) was synthesized by the solvothermal method and characterized using X-ray crystallography. • Due to phenomenal properties of methyl, methyl group is an interesting group for designing of MOFs. • Since these compounds contain amine-functionalized linker, they can interact favorably with phenol compounds as fluorescent materials. • TMU-59 has exhibited an excellent selectivity for TNP detecting and the remarkable LOD equal to 0.63 nM. The strategy of MOFs functionalization by modifying ligands is a powerful platform among other ongoing researchs which is creating high-performance MOFs. Ligands modification through the addition of support groups (in helping of host–guest main interaction sites) has a key role in the increasing of host molecule adsorption capacity. To investigate this issue we synthesized two structures TMU-59 and TMU-6(RL1) and studied the effect of MOFs functionalization with functional groups such as methyl group in the vicinity of basic amine groups on the detection of guest molecules. The sensing ability of TMU-6(RL1) as parent structure and methyl functionalized TMU-59 has studied for the detection of TNP in aqueous solutions. Our results reveal that the insertion of methyl groups on pillaring linker can remarkably increase the hydrophobicity, stability and electron density of MOFs as well as maximizing the interaction with the nitro-aromatics guests by providing multiple adsorption mechanisms such as hydrogen bonds and π-π interactions. The detection limit for TNP in water solvent is 0.46 and 102 ppb for TMU-59 and TMU-6(RL), respectively. Present work as a comprehensive study reveals that how MOFs functionalization through the addition of relatively active group such as methyl would have influenced the overall sensing behavior. [ABSTRACT FROM AUTHOR]

Abstract Reaction of the phenanthridine ligand (phend) with ZnBr 2 in DMSO/MeOH or MeOH yielded the complexes ZnBr 2 (phend)(DMSO) (1) and ZnBr 2 (phend) 2 (2) respectively. These complexes were characterized by single crystal X-ray diffraction, IR spectroscopy and elemental analyses. Sonochemical preparation of complexes 1 and 2 in methanolic solution generated porous texture (pt) crystals 1 pt and 2 pt. Comparison of the X-ray powder diffraction data confirmed identical crystal structures for 1 and 1 pt as well as 2 and 2 pt. The porous texture (the mixture of nano-porous and micro-pores) morphologies of the sonochemical products were confirmed by scanning electron microscopy. Reaction conditions, such as solvent and the concentration of the initial reagents, played important roles in the size and growth process of the crystalline products. Graphical abstract Image 1 Highlights • Changing solvent has a significant impact on the crystal packing of a series of Zn(II) coordination complexes. • The C H⋯Br hydrogen bonds interactions have a great role in the formation of the multi-dimensional crystal structure. • The C H.⋯Br hydrogen bonds and C H ... π interactions administer the crystal structure. [ABSTRACT FROM AUTHOR]

Two new fluorinated metal–organic frameworks [Zn2(hfipbb)2(4-bpdh)]·0.5DMF (TMU-55) and [Zn2(hfipbb)2(4-bpdb)]·2DMF (HTMU-55) have been solvothermally synthesized by the reaction of two linear N-containing ligands as pillars (4-bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene and 4-bpdh = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene), and a flexible V-shaped fluorinated linker, H2hfipbb = 4,4′-(hexafluoroisopropylidene) bis(benzoic acid). The two compounds were characterized by different techniques such as X-ray crystallography, powder X-ray diffraction (PXRD), infrared spectroscopy (IR), contact angle (CA), thermogravimetry (TGA), field emission scanning electron microscopy (FE-SEM), inductively coupled plasma (ICP), and Brunauer–Emmett–Teller (BET) surface area analysis. Both compounds are structurally similar and exhibit three dimensional (3D) coordination frameworks with hydrophobic properties. The catalytic activity of these isoreticular F-MOFs as efficient base heterogeneous catalysts toward the Knoevenagel condensation reaction was tested and compared to each other. TMU-55 and HTMU-55 exhibited good catalytic activity (with a minimum amount of catalyst, 2.5 mg (0.5 mol%), and the shortest time, 5 min) in water as a green solvent with excellent conversions. Also, the results were considerably higher in comparison with most of the values given in the literature for this reaction at ambient temperature. The remarkable catalytic performance of TMU-55 and HTMU-55 in water can be attributed to the presence of hydrophobic fluoro groups near the basic reaction center in the F-MOFs. These catalysts maintain their crystalline frameworks after the reaction and are easily recovered and reused at least for three cycles without significant loss in their catalytic activity. Furthermore, the conversion of benzaldehyde can be kept over 95% while the selectivity of the Knoevenagel reaction is kept at 100%. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Abrasion resistance of polyurethane clearcoats is significantly enhanced by nano-silica additives. • Scratch, abrasion, SEM & TEM results are presented. • The effect of different weight fractions and applied abrasion forces is evaluated. • Abrasion resistance improvement is discussed using wear mechanisms. • Much more economical coatings can be fabricated using precipitated type of nano-silica reinforcement. Abstract Nano-particulate reinforced polymer composites are recently being used in many laboratory and industrial applications such as automotive manufacturing industries. However, still further studies are demanded to enhance tribological and mechanical properties leading to achieve as the best resilience as possible required for severe loading or harsh environmental conditions. The purpose of the current paper is studying the scratch and abrasion resistance of the acrylic-based polyurethane nano-particulate clearcoats reinforced by the two types of fumed and precipitated nano-silica reinforcements. To do this, scanning electron microscope (SEM), transmission electron microscope (TEM), scratch and pin-on-disc abrasion resistance experiments were carried out. It was found that the nano-silica additives considerably enhance tribological and mechanical properties of the examined coatings. It was also found that the precipitated type of nano-silica clearcoat is hard enough, tough, and very resistant against wear and environmental conditions and therefore can be considered instead of the too expensive fumed type of nano-silica. [ABSTRACT FROM AUTHOR]

This paper provides a novel magnetic assisted turning mechanism for machining steel alloy specimens by HSS tools. The presented setup reduces air gap on a closed magnetic circuit and applies the magnetic field on both tool and workpiece, simultaneously. The usage of closed magnetic field contributes to using the magnetic field advantages at lower magnetic intensity. Using the design of experiments method, full factorial technique, 3 3 ×2 tests were conducted to study the influence of effective parameters i.e., magnetic field, depth of cut, feed rate and spindle speed. The flank wear and the cutting force were measured to quantitatively investigate the effect of magnetic treatment on machining process. The results were investigated by the analysis of variance (ANOVA) method and the magnetic field was revealed as the most pivotal factor. The analysis of variance results, micrographs of tool wear and dynamometer's force diagrams proved the advantages of the proposed method. Through this technique, a maximum 94% reduction in flank wear and 66% improvement of cutting force were achieved. [ABSTRACT FROM AUTHOR]

Deterministic lateral displacement (DLD) is a passive separation method that separates particles by hydrodynamic size. This label-free method is a promising technique for cell separation because of its high size resolution and insensitivity to flow rate. Development of capillary-driven microfluidic technologies allows microfluidic devices to be operated without any external power for fluid pumping, lowering their total cost and complexity. Herein, we develop and test a DLD-based particle and cell sorting method that is driven entirely by capillary pressure. We show microchip self-filling, flow focusing, flow stability, and capture of separated particles. We achieve separation efficiency of 92% for particle–particle separation and more than 99% efficiency for cell–particle separation. The high performance of driven flow and separation along with simplicity of the operation and setup make it a valuable candidate for point-of-care devices. [ABSTRACT FROM AUTHOR]

Finishing freeform complex surfaces with limited access has been raised as a challenging issue in advanced manufacturing industries. In this study, a new magnetic abrasive finishing (MAF) apparatus for finishing internal spiral grooves of a cylindrical tube is proposed. The MAF setup was installed on a CNC machine for performing experimental trials. A full factorial design approach was used and the results of the experiments were analyzed by analysis of variance (ANOVA) technique. Through this study, the effectiveness of finishing parameters including tool rotational speed, finishing time, and abrasive mesh number on the grooves' surface roughness was investigated. Microscopic surface profiles and patterns demonstrate 70% improvement in the surface roughness. [ABSTRACT FROM AUTHOR]

A 3D, porous Zn(II)-based metal–organic framework {[Zn 2 (oba) 2 (4-bpmn)]·(DMF) 1.5 } n ( TMU-21 ), (4-bpmn = N,N ′ - Bis-pyridin-4-ylmethylene-naphtalene-1,5-diamine, H 2 oba = 4,4′-oxybis(benzoic acid)) with nano-rods morphology under ultrasonic irradiation at ambient temperature and atmospheric pressure was prepared and characterized by scanning electron microscopy. Sonication time and concentration of initial reagents effects on the size and morphology of nano-structured MOFs were studied. Also {[Zn 2 (oba) 2 (4-bpmn)] ( TMU-21 ) and {[Zn 2 (oba) 2 (4-bpmb)] ( TMU-6 ), 4-bpmb = N,N’-(1,4-phenylene)bis(1-(pyridin-4-yl)methanimine) were easily prepared by mechanochemical synthesis. Nanostructures of Zinc(II) oxide were obtained by calcination of these compounds and their de-solvated analogue as activated MOFs, at 550 °C under air atmosphere. As a result of that, different Nanostructures of Zinc(II) oxide were obtained. The ZnO nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy. [ABSTRACT FROM AUTHOR]

Two new Hg(II) and Cd(II) one-dimensional coordination polymers have been constructed from metal iodide and a N , N ′-Bis-pyridin-4-ylmethylene-naphthalene-1,5-diamine ligand using conventional methods. The effects of the ligand geometry and the coordination modes of iodide on the structures of the coordination polymers have been discussed in detail. In order to clarify the effect of experimental conditions on the morphology and size of [Cd(L)I 2 ] n (1) and [Hg(L)I 2 ] n particles, we have systematically investigated the influence of concentration and sonication power on the size of the resulting products for the aim of realizing controllable synthesis. The results indicated that the concentration and sonication power directly influenced the final size of nanostructures of these coordination polymers. The prepared nanocrystals of these two coordination polymers were analyzed using scanning electron microscopy, infrared spectroscopy and X-ray powder diffraction. [ABSTRACT FROM AUTHOR]

The motivation of this work is to highlight factors that influence the supramolecular structures of d metal coordination polymers. Two novel Hg(II) and Cd(II) 1D coordination polymers (CPs) have been constructed from metal iodide and a N,N′-bis-pyridin-3-ylmethylene-naphtalene-1,5-diamine ligand using conventional methods. Our analyses reveal the substantial role of weak hydrogen bonds and π-π stacking interactions in the assembly of these series of compounds. These compounds were studied using X-ray crystallography, infrared spectroscopy and X-ray powder diffraction. The supramolecular structures of these two compounds were compared with two structures that have been published recently. These coordination polymers in nano-size were synthesized under ultrasonication and their morphology were characterized using scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

Three Ru(II) half-sandwich complexes containing ( N , N )-bound Schiff-base ligands, [(η 6 -C 6 H 6 ) RuCl(L1)]PF 6 ( 1 ) L1 = ( E )-1-(6-methylpyridin-2-yl)-N-( p -tolyl)methanimine , [( η6 - p -cymene)RuCl(L1)]PF 6 ( 2 ) and [(η 6 - p -cymene)RuCl(L2)]PF 6 (3) L2 = ( E )-1-(6-bromopyridin-2-yl)-N-( p -tolyl)methanimine , were synthesized, characterized and their supramolecular structures were analyzed. The crystal packing of these compounds was studied using geometrical analysis and Hirshfeld surface analysis. The fluorescence behavior of these compounds was also studied. TD-DFT calculations were carried out to better understand the fluorescence properties of complexes 1 – 3 . These compounds could be promising for the design of organometallic dye systems. [ABSTRACT FROM AUTHOR]

The importance of N⋯X halogen bonding in a series of -(5-halo-2-pyridinyl)pyrazine-2-carboxamides N has been investigated by different methods. The results show that when nitrogen is substituted for carbon in the aryl backbone of the parent compound, it can affect the electron accepting ability of bromine and iodine substituents. Thus, a stronger halogen bond can be formed. [ABSTRACT FROM AUTHOR]