Geometric Interaction Research Articles

Thiophene appended schiff base probe for selective ‘turn-on’ response for copper (ii) ion and their applications in live cell imaging Thiophene appended schiff base probe for selective ‘turn-on’ response for copper (ii) ion and their applications in live cell imaging

In this research, we have synthesized a thiophene Schiff base from 5-phenyl thiophene-2-carboxaldehyde and 2-thiophene carboxylic acid hydrazide and characterized by using FT-IR NMR, HRMS and SC-XRD analysis techniques. The probe exhibited a selective turn-on fluorescence response for Cu2+ over 20 other common metal ions in a CH3CN (9:1, v/v) solution. The Job’s plot represents a 1:1 binding complexation mode and further DFT study was carried out to aid in understanding the geometric structure and interaction of the ligand and Cu2+. The detection limit (LOD) and limit of quantification (LOQ) were found to be 20 nM and 69 nM respectively. Furthermore, the probe’s sensing ability was tested in HeLa cells and their fluorescence imaging also supported the effective turn-on response towards Cu2+ ion.

Propagation buckling failure of a buried offshore pipeline with integral arrestors under external overpressure and strike-slip faulting disturbance

In this study, the propagation buckling failure of a buried offshore pipeline under external overpressure and strike-slip faulting disturbances was investigated numerically. A nonlinear shell model, accounting for geometric, material, self-contact, and pipe-soil interaction nonlinearities, was developed using the vector form intrinsic element method. The arresting performances of the single- and double-integral arrestors were analyzed based on a series of simulations considering various combinations of arrestor diameter-to-thickness ratios, lengths, and sub-arrestor intervals. A comparative analysis was conducted between single- and double-integral arrestors, focusing on their arresting performance, material usage, and manufacturing complexity. The results revealed that pipelines under external overpressure are prone to local collapse and bidirectional buckling propagation under small fault displacements. Reverse ellipticities occur downstream of the buckling propagation and their development leads to flipping propagation. Buckling arrestors function by exhausting the upstream flattening propagation and inhibiting the development of reverse ellipticities downstream. The material consumption of each single-integral arrestor was significantly higher than that of a double-integral arrestor with the same diameter-to-thickness ratio. The weld count of the double-integral arrestors was lower than that of the single scheme, but this difference narrowed as the pipeline mileage increased. These results can serve as valuable guidelines for the design and construction of pipelines crossing seismic zones.

Prioritization of renewable energy for offshore ship charging stations based on intuitionistic fuzzy GLDS method: A case of China

Offshore ship charging station (OSCS) projects can help to address the current demand for electric ships for ocean voyages to a large extent. The proper selection of the energy source for power generation is a key part of the OSCS project. To select the optimal renewable energy for OSCS with many difficulties such as the ambiguity of the decision-making environment, the differences in group assessment information, and the conflict and compensation between criteria, this paper proposed a fuzzy multi-criteria decision-making (MCDM) framework. First, a comprehensive criteria system was constructed. Second, the intuitionistic fuzzy set (IFS) was introduced to express experts’ fuzzy cognition. Third, based on the quality of evaluation, a novel expert weighting method was proposed, and the generalized intuitionistic fuzzy weighted geometric interaction averaging (GIFWGIA) operator was used to aggregate the individual evaluations. Fourth, the criteria importance through intercriteria correlation (CRITIC) method, and the stepwise weight assessment ratio analysis II (SWARA II) method were introduced to determine the criteria weights. Fifth, considering criteria compensation, and individual and group ranks, the gained and lost dominance score (GLDS) method were used for ranking. Finally, to verify the applicability and reliability of the framework, a case study was conducted in Pingtan Island, Fujian Province. The results show that wind energy was the best alternative, followed by solar, wave and nuclear energy.

Complexes of Hydrogen Peroxide, the Simplest Chiral Molecule, with L- and D-Serine Enantiomers and Their Clusters: MP2 and DFT Calculations.

The interaction between natural amino acids and hydrogen peroxide is of paramount importance due to the widespread use of hydrogen peroxide in biological and environmentally significant processes. Given that both amino acids and hydrogen peroxide occur in nature in two enantiomeric forms, it is crucial to investigate the formation of complexes between them, considering the role of molecular chirality. In this work, we report a theoretical study on the hydrogen peroxide enantiomers and their interactions with L- and S-serine and their clusters. We aimed to evaluate the non-covalent interactions between each hydrogen peroxide enantiomer and the L- and D-enantiomers of the non-essential amino acid serine and their clusters. First, the potential energy surfaces (PES) of transitions between enantiomers of the simplest chiral molecule, hydrogen peroxide, in the gas phase and in aqueous solution were studied using the Møller-Plesset theory method MP2/aug-cc-pVDZ. The activation energies of such transitions were calculated. The interactions of both hydrogen peroxide enantiomers (P and M) with L- and D-serine enantiomers were analyzed by density functional theory (DFT) with ωb97xd/6-311+G**, B3Lyp/6-311+G**, B3P86/6-311+G**, and M06/6-311+G** functionals. We found that both enantiomers of hydrogen peroxide bind more strongly to L-serine and its clusters than to D-serine, especially highlighting that the L form is the predominant natural form of this and other chiral amino acids. The optimized geometric parameters, interaction energies, and HOMO-LUMO energies for various complexes were estimated. Furthermore, circular dichroism (CD) spectra, which are optical chirality characteristics, were simulated for all the complexes under study.

Characterizing chiroptical properties of 2D/3D structures based on an improved coupled dipole theory.

To reveal the difference/connection between two-dimensional and three- dimensional (2D and 3D) chiroptical properties and their relation with 2D/3D symmetry/breaking, we develop an improved coupled dipole theory (ICDT) based on a model system of nanorod (NR) dimer. Our analytical ICDT can overcome the shortcoming of the traditional coupled dipole theory and points out the important role of scattering circular dichroism (SCD) in characterizing 2D chirality. The ICDT, supported by finite-difference time-domain (FDTD) simulation, reveals the physical origin of 2D chiroptical response: the interaction induced asymmetric effective polarizability for two identical NRs in a symmetry broken configuration. By tuning the NR's position/inter-particle distance, we find an optimal structure of maximum SCD due to the competition between geometric symmetry breaking and interaction. In addition, the interplay between 2D in-plane mirror symmetry breaking and three-dimensional (3D) mirror symmetry breaking leads to a symmetry broken system with zero SCD. The relation between chirality and reciprocity has also been addressed.

Structure and molecular interactions in 1‑ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ion pair conformers: abinitio DFT based study

Density functional theory (DFT) calculations with Grimme’s B97D functional including dispersion are employed to provide both structural and electronic insight into the multifold interactions occurring in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid [EMI][TFSI], which is currently being targeted for applications in next-generation Li-ion battery electrolytes. The geometric structure, interaction energy and natural bond orbital analysis of the ion-pair conformers of [EMI][TFSI] show differences from the conventional H-bonds. A total of six stable [EMI][TFSI] ion pair conformers were observed. Our results show that a doubly ionic H-bond exists between [EMI]+ and [TFSI]− ion pair conformers. The greater the number of multiple H-bond type interactions, the greater the absolute value of the interaction energy. Moreover, results from the NBO analysis show that, for [EMI][TFSI] ion pair conformers, charge transfer occurs mainly from the lone pairs of oxygen and nitrogen atom to the σ-type anti-bonding orbital of the C–H and π-type anti-bonding orbitals of N–C bonds. This was evident from the values of the stabilization energy E(2) associated with each electron delocalization from the donor to acceptor orbitals. There exist large numbers of multiple concomitant hydrogen bonds, but the values of the stabilization energy E(2) are generally small (E(2)n→\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ o$$\\end{document}σ* < 3 kcal/mol) for the individual H-bond interactions. The shorter the C–H···O and/or C–H···N bond is, the larger charge transfer, and the larger the stabilization energy E(2) associated with electron delocalization from donor to acceptor. Generally, the [EMI][TFSI] ion pair conformers tend to form multiple but bent H bonds, reducing the strength of the individual H bonds from a potential (linear) maximum.

Modelling of soil destruction process by bulldozer using a spatially oriented working unit

The article uses approaches to creating a model for calculating soil cutting forces by spatially oriented working units of construction machines used on construction sites. The use of such a model is due to the need for continuous improvement of existing equipment and the creation of new ones, taking into account the existing needs. Today, there is a need for efficient performance of construction works related to the operation of construction equipment with dumping equipment. This, in turn, poses the task of determining the performance of mechanised earthworks in various working environments, one of the most common in Ukraine being marl clay, loam and argillaceous clay.&#x0D; The main method of mechanical soil development is cutting. The main geometric conditions are the position of the cutting wedge edge relative to the cutting direction and the surface of the massif, the outline of the cutting edge, the outline and number of working surfaces of the cutting wedge, the number of so-called side cut surfaces and the so-called blocked cut surfaces. The peculiarity of the digging process is that its power and energy indicators depend on the kinematic conditions and geometric parameters – thickness, width and area of the cut, as well as on the angles of orientation of the working unit in space.&#x0D; The computational model was created in accordance with the working hypothesis, where the movement of spatially oriented knives moves perpendicular to the blade equipment, at different ratios of the blade movement speed and knife movement, which creates spatial interaction with the working environment, and the deviation of the application of the full cutting force by an angle α.&#x0D; In accordance with the working hypothesis, we obtained five plans for the movement of the spatially oriented blade of the blade. Depending on the plan of movement of the spatially oriented knife, its geometric interaction with the working environment changes and the cutting force changes accordingly.&#x0D; The need to create more productive and efficient earthmoving equipment requires the use of modern design solutions. In the course of the study, a model for calculating the cutting of soils by spatially oriented earthmoving tools in the form of a dihedral knife of dump equipment was created. A comparison of soil cutting forces at different depths during the operation of a spatially oriented working body is also proposed. The results are summarised in the form of tabular data and graphs.

Nonlinear geometric fluid-structure interaction model of multilayered sandwich plates in contact with unbounded or bounded fluid flow

Based on the Kirchhoff-Love theory and von Kármán's geometric nonlinearity, the nonlinear vibration analysis of multilayered sandwich plates under ideal flow is presented. Rectangular plates are considered to be laminated of orthotropic composite layers as upper and lower face sheets as well as a central lightweight core made of functionally graded (FG), anisogrid lattice or metal foam materials. Three coupled equations of motion are reformulated into one decoupled governing equation in terms of transverse deflection (w) using the method of inverse differential operator. For the first time, an impermeability condition is developed that considers the moderately large deflection of the contact surface in order to correct the pressure distribution of fluid flow. Based on the potential flow theory, closed-form expressions of hydrodynamic pressure are obtained for different fluid boundary conditions including infinite depth of fluid, flow bounded by a rigid wall and flow between two identical elastic plates. Then, the Galerkin and multiple-scale perturbation methods are used to obtain closed-form solution of nonlinear natural frequency in terms of maximum vibration amplitude. Finally, case studies are presented to investigate the effects of geometric ratios, boundary condition, material distribution, layup, characteristics of flow and geometric nonlinearity on the response quantities. Findings indicate that the large deformation term in the developed impermeability condition has significant effect on the pressure distribution and its effect is more pronounced for thicker plates with larger mode number in the flow direction. Therefore, the novel nonlinear fluid-structure interaction model should be considered to study flow-induced dynamic behavior of sandwich plates with different boundary conditions. In addition, the snap-through behavior is seen in the nonlinear frequency-upstream speed curves and the incipient points of dynamic instability can vary remarkably with the fluid boundary conditions.

Development of a parametric model of the spatially oriented knife on the bulldozer blade

The paper considers the results of the study of resistances arising during the operation of a bulldozer in the soil environment and processes in the drawing prism. What affects the stability and productivity of the bulldozer during excavation works. The geological map of the "Ukrainian crystalline shield" was studied, where the most common soils on the territory of Ukraine were found. Using the proposed hypothesis of the movement of spatially oriented knives on a bulldozer blade, it was shown that when excavating soil at different speed ratios, there is a deviation of the cutting force application vector by an angle (α), which in turn affects the geometric interaction of the spatially oriented knife with the working environment. Changing the geometric interaction of the spatially oriented knife with the soil affects the cutting force, which led to the creation of a parametric model of the interaction of spatially oriented knives with the working environment. The model was developed for different knife configurations and different ratios of the bulldozer speed to the spatially oriented knife movement speed. The total, normal, and orthogonal cutting forces for the working, subcritical, and critical depths of soil cutting were calculated, according to changes in the parametric model of the spatially oriented knife. A comparative calculation of the cutting force by a bulldozer without and with spatially oriented knives was carried out.

An efficient computational protocol for template-based design of peptides that inhibit interactions involving SARS-CoV-2 proteins.

The RNA-dependent RNA polymerase (RdRp) complex of SARS-CoV-2 lies at the core of its replication and transcription processes. The interfaces between holo-RdRp subunits are highly conserved, facilitating the design of inhibitors with high affinity for the interaction interface hotspots. We, therefore, take this as a model protein complex for the application of a structural bioinformatics protocol to design peptides that inhibit RdRp complexation by preferential binding at the interface of its core subunit nonstructural protein, nsp12, with accessory factor nsp7. Here, the interaction hotspots of the nsp7-nsp12 subunit of RdRp, determined from a long molecular dynamics trajectory, are used as a template. A large library of peptide sequences constructed from multiple hotspot motifs of nsp12 is screened in-silico to determine sequences with high geometric complementarity and interaction specificity for the binding interface of nsp7 (target) in the complex. Two lead designed peptides are extensively characterized using orthogonal bioanalytical methods to determine their suitability for inhibition of RdRp complexation. Binding affinity of these peptides to accessory factor nsp7, determined using a surface plasmon resonance (SPR) assay, is slightly better than that of nsp12: dissociation constant of 133nM and 167nM, respectively, compared to 473nM for nsp12. A competitive ELISA is used to quantify inhibition of nsp7-nsp12 complexation, with one of the lead peptides giving an IC50 of 25μM . Cell penetrability and cytotoxicity are characterized using a cargo delivery assay and MTT cytotoxicity assay, respectively. Overall, this work presents a proof-of-concept of an approach for rational discovery of peptide inhibitors of SARS-CoV-2 protein-protein interactions.

Geometric Interaction Graph Neural Network for Predicting Protein-Ligand Binding Affinities from 3D Structures (GIGN).

Predicting protein-ligand binding affinities (PLAs) is a core problem in drug discovery. Recent advances have shown great potential in applying machine learning (ML) for PLA prediction. However, most of them omit the 3D structures of complexes and physical interactions between proteins and ligands, which are considered essential to understanding the binding mechanism. This paper proposes a geometric interaction graph neural network (GIGN) that incorporates 3D structures and physical interactions for predicting protein-ligand binding affinities. Specifically, we design a heterogeneous interaction layer that unifies covalent and noncovalent interactions into the message passing phase to learn node representations more effectively. The heterogeneous interaction layer also follows fundamental biological laws, including invariance to translations and rotations of the complexes, thus avoiding expensive data augmentation strategies. GIGN achieves state-of-the-art performance on three external test sets. Moreover, by visualizing learned representations of protein-ligand complexes, we show that the predictions of GIGN are biologically meaningful.

Geometric algebra-based multiview interaction networks for 3D human motion prediction

3D skeleton-based human motion prediction is an essential and challenging task for human-machine interactions, which aims to forecasts future poses given a history of their previous motions. Recent works based on Graph Neural Networks (GCNs) show promising performance for motion prediction due to the powerful ability of feature aggregation of GCNs. However, with the deep and multi-stage GCN model deployment, its feature extraction mechanism tends to result in feature similarity over all joints, and degrade the prediction performance. In addition, such a graph structure in recent works was still insufficient to process the high dimensional structural data in Euclidean space when inference through multi-layer networks. To solve the problem, we propose a novel Geometric Algebra-based Multi-view Interaction network (GA-MIN), which captures and aggregates motion features from two interactions: 1) global-interaction, which refactors various spectrum dependencies using geometric algebra-based structure, and 2) self-interaction, which leverage self-attention mechanism to capture compact representations. Extensive experiments are conducted on three public datasets: Human3.6M, CMU Mocap, and 3DPW, which prove that the proposed GA-MIN outperforms state-of-the-art methods on 3D Mean Per Joint Position Error (MPJPE) and Mean Angle Error (MAE) on average.

A control method with considering error coupling in milling multi-feature thin-walled parts

Multiple features of thin-walled parts have position-dependent and dimension association, which means that multi-feature machining errors can affect each other. They may be coupled in multiple processes. Therefore, multi-feature couple effect plays a significant impact on thin-walled parts machining process in some cases. The most existing error coupling analysis methods ignore the error influence between features. To overcome this problems, Multi-feature machining is investigated thoroughly, error coupling method is proposed to consider these effects in this paper. According to the influence mode of multi-feature machining, error coupling is decomposed into geometric interaction and machining interaction, and analyze individual influence mode. The geometric interaction is tolerance/datum interactions. The machining interaction is generated from machining operations. A method based on SDT (small displacement torsors) and transformation of the coordinate systems is employed and integrated to the comprehensive error model. Besides, a compensation method by adjusting the pose is proposed. Finally, a case study is performed to validate the proposed method.

Light field spatial super‐resolution via geometric feature interaction

Light field (LF) enables high-dimensional image data representation since it can capture spatial and angular information of light rays simultaneously. The low spatial resolution caused by the limited imaging ability of the capturing equipment and the trade-off between spatial and angular resolution greatly affects the quality and application of LF images. Here, an end-to-end LF super-resolution method is proposed via geometric feature interaction. First, the low-resolution LF images are stacked in the horizontal and vertical epipolar plane image (EPI) directions and form 3D VI stacks. Then, these stacks are put into a dual-branch network, and 3D convolution is alternately performed on the viewpoint images (VIs) and EPIs by reshaping features for better feature extraction and interaction. The proposed method can fully explore the texture information and geometric consistency of the LF, and super-resolve all VIs at the same time. Experimental results on both real-world and synthetic LF datasets show that the proposed method has higher performance than other state-of-the-art methods.

Searching Geometric Patterns in Protein Binding Sites and Their Application to Data Mining in Protein Kinase Structures.

The ever-growing number of protein-ligand complex structures can give fundamental insights into protein functions and protein-ligand interactions, especially in the field of protein kinase research. The number of tools to mine this data for individually defined structural motifs is restricted due to the challenging task of developing efficient index structures for 3D data in relational databases. Herein we present GeoMine, a database system with web front-end mining of more than 900 000 binding sites. It enables database searches for geometric (interaction) patterns in protein-ligand interfaces by, for example, textual, numerical, substructure, similarity, and 3D searches. GeoMine processes reasonably selective user-defined queries within minutes. We demonstrate its usability for advancing protein kinase research with a special emphasis on unusual interactions, their use in designing selective kinase inhibitors, and the analysis of reactive cysteine residues that are amenable to covalent kinase inhibitors. GeoMine is freely available as part of our modeling support server at https://proteins.plus.

Analysis of migration behavior of aggregate-asphalt system based on interface effect of particles

The spatial migration of aggregate-asphalt system is the internal manifestation of the shear deformation of asphalt mixture. To elucidate the migration mechanism, five asphalt mixtures were measured by two self-developed testers and a new evaluation method was proposed. The migration behaviors were analyzed based on interface effect involving composite geometric characteristics of coarse aggregates, contact properties of particle system and interface interaction between aggregates and asphalt binder. The results show that the maximum migration shear stress can effectively evaluate the migration behaviors of the aggregates-asphalt system. The migration behaviors of aggregate-asphalt system are predominantly affected by the interface effect which is closely related to the composite geometric characteristics, contact properties and interface interaction. The higher the composite angularity index of coarse aggregates doesn’t mean the stronger the capability of resisting the migration due to the influence of bonding and lubrication effect of asphalt binder. The bonding effect of asphalt has a poor ability to restrict the movement of large-sized fine aggregates, leading to the fine aggregates to significantly interfere with the skeleton structure of asphalt mixture.

Discharge Characteristics of Different Shaped Particles from an Inclined Bottom Rectangular Hopper

In order to further explore the discharge characteristics of different shaped particles from the inclined bottom hopper, the discharge of four shaped particles from an inclined bottom rectangular hopper was studied based on the discrete element method (DEM). Non-spherical particles were established based on the multi-spheres method. The effects of geometric parameters, particle properties, and interaction parameters on discharge were investigated. Some interesting results have been found that regular spherical particles are more easily discharged from the hopper, and the time required to empty the hopper is the shortest. The influence of particle shape on discharge takes precedence over that of solid fraction. Both the critical angle (55°) and the correlation between the 2/3 power of the mass discharge rate and the orifice width are independent of the particle shape. Blockage occurs as the angle and/or the ratio of particle size to orifice width increases. The dihedral angle is the key factor affecting the blockage. Compared with spherical particles, non-spherical particles are more prone to blockage and have stronger blockage strength.

A Flexible 3D Printed Template to Assist with Physician Modified Endografts for FEVAR

Fenestrated endovascular aneurysm repair (FEVAR) for juxtarenal AAAs is limited by cost and the availability of custom made endografts, in addition to technical complexity. Rigid 3D printed anatomical models of the visceral aorta have been used to supplement fenestration placement and as an alternative to conventional centreline based planning; however, these do not simulate the geometric interaction between wires, delivery system, endograft, and aortic tissue. We present a novel translucent, flexible 3D printed template which simulates aortic conformation. Flexible templates better approximate the straightening of native aorta when endografts are deployed and may assist fenestration planning to reduce the risk of splanchnic vessel misalignment. The visceral segment of a juxtarenal AAA was modelled from a computed tomography aortogram, with the splanchnic vessels cropped at their origin to allow fenestrations to be marked (Fig. 1). A Projet 3500 3D printer (3D Systems Corporation, Rock Hill, USA; cost €70 000) was used to print the flexible template. The 3D printed templates are sterilised using ethylene oxide or autoclave techniques. Lunderquist wire cannulation was performed with deployment of an off the shelf Endurant endograft (Medtronic Inc., Minnesota, USA). Splanchnic branch ostia were marked with a sterile pen (Fig. 2). The material was translucent to avoid positioning the fenestrations over struts.Figure 2Fenestrations are planned by marking through the template with a sterile marking pen.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The template was 3D printed in flexible resin (Visijet CE-NT, 3D Systems) on its first attempt over 24 h, costing €95 in materials. This presents a significant time advantage over commercial fenestrated endografts, which require a minimum of one month lead time. In addition, 3D printed template assisted physician modified stent grafts result in substantial cost savings when compared with commercial alternatives. Flexible models may also assist with validation of commercial FEVAR graft construction. 3D printed templates to assist with the back table fenestration of standard commercial endografts are a promising frontier for FEVAR. We report the first instance of a flexible template which mitigates some limitations surrounding templates 3D printed with rigid materials. None.

Free Energy Computation of Particles with Membrane-Mediated Interactions Via Langevin Dynamics

We apply well-established concepts of Langevin sampling to derive a new class of algorithms for the efficient computation of free energy differences of fluctuating particles embedded in a 'fast' membrane, i.e., a membrane that instantaneously adapts to varying particle positions. A geometric potential accounting for membrane-mediated particle interaction is derived in the framework of variational hybrid models for particles in membranes. Recent explicit representations of the gradient of the geometric interaction potential allows to apply well-known gradient based Markov Chain Monte-Carlo (MCDC) methods such as Langevin-based sampling.

Highly active and stable Pd/MgAl2O4@MgO catalyst with electronic metal-support interaction for selective hydrogenation of isoprene

Electronic metal-support interaction (EMSI) had attracted increasing attention to tailor the electronic and catalytic properties of supported metal catalysts. In this work, we constructed a hierarchical Pd/MgAl2O4@MgO catalyst with flake-like MgO densely distributed on the surface of MgAl2O4. High specific surface MgAl2O4@MgO contributed to disperse and stabilize Pd particles and induced EMSI that allowing for electron donation from MgO to Pd. This was identified by the increase of the electronic density of Pd and the changes in CO adsorption behavior. Compared with Pd/MgAl2O4, Pd/MgO and Pd/Al2O3 catalysts, the as-prepared Pd/MgAl2O4@MgO catalyst exhibited significantly higher activity and selectivity with excellent stability for selective hydrogenation of isoprene. The improved catalytic activity and stability could be associated with the electronic and geometric interaction between Pd and MgAl2O4@MgO, which promoted the dissociation of H2 and weakened the adsorption of semi-hydrogenation products.