Centroid Distance Research Articles

Crystal structure of poly[tetra-μ-cyanido-ethanol-bis(2-iodo-pyrazine)-digold(I)iron(II)

In the title polymeric complex, [Au2Fe(CN)4(C4H3IN2)2(C2H6O)] n , the FeII cation is coordinated by two iodo-pyrazine mol-ecules, one ethanol mol-ecule and three di-cyano-aurate anions in a distorted N5O octa-hedral geometry. In the crystal, the di-cyano-aurate anions bridge the FeII cations to form polymeric chains propagating along the b-axis direction. Stabilization of the crystal structure is provided by O-H⋯N hydrogen bonds and π-π stacking between parallel iodo-pyrazine rings of neighbouring chains, the centroid-centroid distances being 3.654 (10) and 3.658 (9) Å.

4-(Prop-2-yn-1-ylsulfanyl)-1H-pyrazolo[3,4-d]pyrimidine

The asymmetric unit of the title compound, C8H6N4S, consists of two independent molecules differing in the orientation of the side chain. In the crystal, molecules form dimers through N—H...N hydrogen bonds. The dimers stack along thea-axis direction with weak π–π stacking interactions [centroid–centroid distances of 3.898 (2) and 3.908 (2) Å]. The crystal studied was refined as a two-component twin.

Crystal structure of methyl (Z)-2-[(Z)-3-methyl-2-({(E)-1-[(R*)-4-methyl-cyclo-hex-3-en-1-yl]ethyl-idene}hydrazinyl-idene)-4-oxo-thia-zolidin-5-yl-idene]acetate.

The new title 4-thia-zolidinone derivative, C16H21N3O3S, was obtained from the cyclization reaction of 4-methyl-3-thio-semicarbazone and dimethyl acetyl-enedi-carboxyl-ate (DMAD). The cyclo-hexyl-idene ring has an envelope conformation with the stereogenic centre C atom as the flap. Its mean plane makes a dihedral angle of 56.23 (9)° with the thia-zolidine ring mean plane. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds forming chains propagating in the [001] direction. Within the chains there are offset π-π inter-actions between the thia-zolidine rings of inversion-related mol-ecules [centroid-centroid distance = 3.703 (1) Å]. The chains are linked by further C-H⋯O hydrogen bonds, forming slabs parallel to the ac plane.

A novel dual-camera calibration method for 3D optical measurement

A novel dual-camera calibration method is presented. In the classic methods, the camera parameters are usually calculated and optimized by the reprojection error. However, for a system designed for 3D optical measurement, this error does not denote the result of 3D reconstruction. In the presented method, a planar calibration plate is used. In the beginning, images of calibration plate are snapped from several orientations in the measurement range. The initial parameters of the two cameras are obtained by the images. Then, the rotation and translation matrix that link the frames of two cameras are calculated by using method of Centroid Distance Increment Matrix. The degree of coupling between the parameters is reduced. Then, 3D coordinates of the calibration points are reconstructed by space intersection method. At last, the reconstruction error is calculated. It is minimized to optimize the calibration parameters. This error directly indicates the efficiency of 3D reconstruction, thus it is more suitable for assessing the quality of dual-camera calibration. In the experiments, it can be seen that the proposed method is convenient and accurate. There is no strict requirement on the calibration plate position in the calibration process. The accuracy is improved significantly by the proposed method.

(E)-2,4-Dibromo-6-(hydrazinylidenemethyl)phenol

The title compound, C7H6Br2N2O, was obtained from a condensation reaction of 3,5-dibromo-2-hydroxybenzaldehyde and hydrazine hydrate. The molecule is approximately planar, the largest deviation from the mean plane through all of the non-H atoms being 0.053 (1) Å. The molecular conformation is stabilized by an intramolecular O—H...N hydrogen bond, generating anS(6) ring motif. In the crystal, intermolecular N—H...Br and N—H...O hydrogen bonds link the molecules, forming chains parallel to thebaxis. Molecules are further linked by π–π stacking interactions, with centroid–centroid distances of 3.925 (3)–3.926 (3) Å, forming a three-dimensional network.

A novel method for 2D nonrigid partial shape matching

Abstract There are two categories of partial shape matching problem: whole-to-part matching and part-to-part matching. The first establishes the best match between an open curve and a part of a closed curve, while the second is to find a part of the first input closed curve that can be well aligned with a part of the second input closed curve. In this paper, we present a novel approach to solve these two categories of the partial shape matching problem. First, we propose a novel shape descriptor, triangular centroid distances (TCDs), for shape representation; the TCDs shape descriptor is invariant to translation, rotation, scaling, and considerable shape deformations. Then, using the TCDs shape descriptor, we present a method to deal with the whole-to-part partial shape matching problem. Finally, we extend our work to part-to-part partial shape matching. Here, we propose a new approach, again using the TCDs shape descriptor, to solve the part-to-part partial shape matching problem. Experimental results demonstrate that our method outperforms existing methods in 2D nonrigid partial shape matching.

Pretreatment T2-Weighted Fluid Attenuated Inversion Recovery (T2-FLAIRpre) MRI May Improve Gross Tumor Volume Delineation for Recurrent Glioblastoma Treated with Salvage Hypofractionated Stereotactic Radiation Therapy

Few treatment options exist for recurrent GBM. HFSRT has been used as a salvage treatment strategy. Gross tumor volume (GTV) is usually based on pretreatment contrast enhanced T1-weighted (T1-contrastpre) MR image. T2-FLAIRpremay detect additional subtle signal of tumor infiltration. This study aimed to investigate the patterns of recurrence following salvage HFSRT using T2-FLAIR image in addition to T1-contrast in target delineation for HFSRT. We retrospectively examined 13 patients with recurrent GBM treated with HFSRT from 2015 to 2017 who had local recurrence following HFSRT. A median dose of 30 (25-35) Gy in 5 to 10 fractions was delivered. The median time between HFSRT and recurrence after HFSRT was 178 (48-259) days. Diagnostic MRI was performed before and 4 weeks after HFSRT, and then every 4 - 8 weeks. Separate GTVs using T1-contrastpre only, T2-FLAIRpre only, or T1pre+T2pre, were contoured blindly by a single radiation oncology physician. Recurrence volume was delineated on the post-treatment T1-contrast (T1-contrastpost) MRI at the time of progression. The volume overlapping between pretreatment GTV and recurrence volume was calculated. The centroid distance between pre- and post-treatment volumes was measured as well. Wilcoxon test was used to assess the statistical significance of differences. The median volumes overlapping between T1-contrastpre, T2-FLAIRpre, T1pre+T2pre and T1-contrastpost were 18% (range: 0-100%, Q1: 12%, Q3: 40%), 52% (range: 0-90%, Q1: 24%, Q3: 59%) and 53% (range: 0-100%, Q1: 26%, Q3: 77%), respectively. The recurrent volume overlapping with T1pre+T2pre was significantly larger than the overlap with T1-contrastpre (p=0.003). The median volume difference between T1-contrastpre and T2-FLAIRpre volumes resided in the recurrence volume was 3.9 cm3 (range: 0-11.5 cm3, Q1: 0.2 cm3, Q3 5.6 cm3). The centroid distance between volumes did not show significant difference. The median centroid distances between recurrence volume and T1-contrastpre volume, T2-FLAIRpre volume, and T1pre+T2prevolume were 1.3 cm (range: 0.3-4.9 cm, Q1: 0.8, Q3: 2.00), 1.3 cm (range: 0.3-4.7 cm, Q1: 0.8 cm, Q3: 2 cm) and 1.2 cm (range: 0.2-1.2 cm, Q1: 0.7 cm, Q3: 2.1 cm), respectively. A significant volume of recurrence occurred in the T1pre+T2pre region beyond the T1-contrastpre region. Further studies to investigate techniques incorporating T2-FLAIRpreregion may improve GTV delineation for salvage HFSRT.Abstract 3551; TableT1-contrastpreT2-FLAIRpreT1pre+T2preTarget overlappingDistance (cm)Target overlappingDistance (cm)Target overlappingDistance (cm)Maximum99%4.9100%4.7100%4.6Q340%2.059%2.077%2.1Median18%1.352%1.353%1.2Q112%0.824%0.826%0.7Minimum0%0.30%0.30%0.2 Open table in a new tab

COMPARISON OF ADJACENCY AND DISTANCE-BASED APPROACHES FOR SPATIAL ANALYSIS OF MULTIMODAL TRAFFIC CRASH DATA

Abstract. Many studies have utilized the spatial correlations among traffic crash data to develop crash prediction models with the aim to investigate the influential factors or predict crash counts at different sites. The spatial correlation have been observed to account for heterogeneity in different forms of weight matrices which improves the estimation performance of models. But very rarely have the weight matrices been compared for the prediction accuracy for estimation of crash counts. This study was targeted at the comparison of two different approaches for modelling the spatial correlations among crash data at macro-level (County). Multivariate Full Bayesian crash prediction models were developed using Decay-50 (distance-based) and Queen-1 (adjacency-based) weight matrices for simultaneous estimation crash counts of four different modes: vehicle, motorcycle, bike, and pedestrian. The goodness-of-fit and different criteria for accuracy at prediction of crash count reveled the superiority of Decay-50 over Queen-1. Decay-50 was essentially different from Queen-1 with the selection of neighbors and more robust spatial weight structure which rendered the flexibility to accommodate the spatially correlated crash data. The consistently better performance of Decay-50 at prediction accuracy further bolstered its superiority. Although the data collection efforts to gather centroid distance among counties for Decay-50 may appear to be a downside, but the model has a significant edge to fit the crash data without losing the simplicity of computation of estimated crash count.

2-(Pyridin-2-yl)-1,8-naphthyridine

The title compound, C13H9N3, has three symmetry-independent molecules in the asymmetric unit. The dihedral angles between the naphthyridine ring system and the pyridine group are in the range 3.927 (4)–7.362 (4)°. In the crystal, C—H...N interactions and aromatic π–π stacking [centroid–centroid distances = 3.5755 (7) and 3.6544 (7) Å] generate a three-dimensional network.

Accuracy of tree diameter estimation from terrestrial laser scanning by circle-fitting methods

This study compares the accuracies of diameter at breast height (DBH) estimations by three initial (minimum bounding box, centroid, and maximum distance) and two refining (Monte Carlo and optimal circle) circle-fitting methods The circle-fitting algorithms were evaluated in multi-scan mode and a simulated single-scan mode on 157 European beech trees (Fagus sylvatica L.). DBH measured by a calliper was used as reference data. Most of the studied circle-fitting algorithms significantly underestimated the mean DBH in both scanning modes. Only the Monte Carlo method in the single-scan mode significantly overestimated the mean DBH. The centroid method proved to be the least suitable and showed significantly different results from the other circle-fitting methods in both scanning modes. In multi-scan mode, the accuracy of the minimum bounding box method was not significantly different from the accuracies of the refining methods The accuracy of the maximum distance method was significantly different from the accuracies of the refining methods in both scanning modes. The accuracy of the Monte Carlo method was significantly different from the accuracy of the optimal circle method in only single-scan mode. The optimal circle method proved to be the most accurate circle-fitting method for DBH estimation from point clouds in both scanning modes.

A novel hierarchical clustering algorithm for the analysis of 3D anthropometric data of the human head

In recent years, the use of 3D anthropometry for product design has become more appealing because of advances in mesh parameterisation, multivariate analyses and clustering algorithms. The purpose of this study was to introduce a new method for the clustering of 3D head scans. A novel hierarchical algorithm was developed, in which a squared Euclidean metric was used to assess the head shape similarity of participants. A linkage criterion based on the centroid distance was implemented, while clusters were created one after another in an enhanced manner. As a result, 95.0% of the studied sample was classified inside one of the four computed clusters. Compared to conventional hierarchical techniques, our method could classify a higher ratio of individuals into a smaller number of clusters, while still satisfying the same variation requirements within each cluster. The proposed method can provide meaningful information about the head shape variation within a population, and should encourage ergonomists to use 3D anthropometric data during the design process of head and facial gear.

9-Amino-5,7-dibromo-1,2,3,4-tetrahydroacridine hemihydrate

The asymmetric unit of the title compound, C13H12Br2N2·0.5H2O, includes two molecules of 5,7-dibromo-1,2,3,4-tetrahydroacridin-9-amine and one water molecule. In the crystal, C—H...O, N—H...N, N—H...O and O—H...N hydrogen bonds connect the molecules, forming a two-dimensional network parallel to (010). The two-dimensional sheets are further assembled into a three-dimensional structure through C—H...π and π–π stacking interactions [centroid–centroid distance = 3.719 (2) Å].

MIST: Accurate and Scalable Microscopy Image Stitching Tool with Stage Modeling and Error Minimization

Automated microscopy can image specimens larger than the microscope’s field of view (FOV) by stitching overlapping image tiles. It also enables time-lapse studies of entire cell cultures in multiple imaging modalities. We created MIST (Microscopy Image Stitching Tool) for rapid and accurate stitching of large 2D time-lapse mosaics. MIST estimates the mechanical stage model parameters (actuator backlash, and stage repeatability ‘r’) from computed pairwise translations and then minimizes stitching errors by optimizing the translations within a (4r)2 square area. MIST has a performance-oriented implementation utilizing multicore hybrid CPU/GPU computing resources, which can process terabytes of time-lapse multi-channel mosaics 15 to 100 times faster than existing tools. We created 15 reference datasets to quantify MIST’s stitching accuracy. The datasets consist of three preparations of stem cell colonies seeded at low density and imaged with varying overlap (10 to 50%). The location and size of 1150 colonies are measured to quantify stitching accuracy. MIST generated stitched images with an average centroid distance error that is less than 2% of a FOV. The sources of these errors include mechanical uncertainties, specimen photobleaching, segmentation, and stitching inaccuracies. MIST produced higher stitching accuracy than three open-source tools. MIST is available in ImageJ at isg.nist.gov.

6-Bromoquinoline-8-carbonitrile

In the title compound, C10H5BrN2, the whole molecule is essentially planar (r.m.s. deviation = 0.005 Å). The crystal packing features face-to-face π–π stacking interactions [centroid–centroid distance = 3.755 (3) Å] between the pyridine and benzene rings of the quinoline ring systems of adjacent molecules, along the a-axis direction. Short Br...Br contacts of 3.5908 (12) Å (compared to a van der Waals separation of 3.70 Å) are also observed.

Structural Covariance Networks in Children with Autism or ADHD.

BackgroundWhile autism and attention-deficit/hyperactivity disorder (ADHD) are considered distinct conditions from a diagnostic perspective, clinically they share some phenotypic features and have high comorbidity. Regardless, most studies have focused on only one condition, with considerable heterogeneity in their results. Taking a dual-condition approach might help elucidate shared and distinct neural characteristics.MethodGraph theory was used to analyse topological properties of structural covariance networks across both conditions and relative to a neurotypical (NT; n = 87) group using data from the ABIDE (autism; n = 62) and ADHD-200 datasets (ADHD; n = 69). Regional cortical thickness was used to construct the structural covariance networks. This was analysed in a theoretical framework examining potential differences in long and short-range connectivity, with a specific focus on relation between central graph measures and cortical thickness.ResultsWe found convergence between autism and ADHD, where both conditions show an overall decrease in CT covariance with increased Euclidean distance between centroids compared with a NT population. The 2 conditions also show divergence. Namely, there is less modular overlap between the 2 conditions than there is between each condition and the NT group. The ADHD group also showed reduced cortical thickness and lower degree in hub regions than the autism group. Lastly, the ADHD group also showed reduced wiring costs compared with the autism groups.ConclusionsOur results indicate a need for taking an integrated approach when considering highly comorbid conditions such as autism and ADHD. Furthermore, autism and ADHD both showed alterations in the relation between inter-regional covariance and centroid distance, where both groups show a steeper decline in covariance as a function of distance. The 2 groups also diverge on modular organization, cortical thickness of hub regions and wiring cost of the covariance network. Thus, on some network features the groups are distinct, yet on others there is convergence.

Topology optimization of planar linkage mechanisms for path generation without prescribed timing

The synthesis of planar linkage mechanisms by a topology optimization method has recently received much attention because both their numbers and dimensions can be simultaneously determined without baseline layouts. To synthesize a mechanism to produce a desired path at its end-effector, a desired path can be defined with or without prescribed timing. While earlier topology optimizations of mechanisms were all concerned with paths with prescribed timing, no study to deal with the topology optimization of mechanisms for path generation without prescribed timing is carried out in spite of its importance. The aim of this study is to propose and set up a gradient-based topology optimization formulation to synthesize planar linkage mechanisms that generate desired paths without prescribed timing. To this end, the desired path of the end-effector is expressed by the centroid distance function which is then represented by its Fourier descriptors. Then a topology optimization formulation using the Fourier descriptors is developed and the sensitivity analysis based on the Fourier descriptors is derived. Several numerical case studies are considered to verify the effectiveness of the proposed formulation. Some numerical issues appearing with the use of the Fourier descriptors are also investigated.

Crystal structure of di-bromo-meth-oxy-seselin (DBMS), a photobiologically active pyran-ocoumarin.

The title compound, C15H14Br2O4 [systematic name: rac-(9S,10R)-3,9-dibromo-10-methoxy-8,8-dimethyl-9,10-dihydropyrano[2,3-h]chromen-2(8H)-one], is a pyran-ocoumarin derivative formed by the bromination of seselin, which is a naturally occurring angular pyran-ocoumarin isolated from the Indian herb Trachyspermum stictocarpum. In the mol-ecule, the benzo-pyran ring system is essentially planar, with a maximum deviation of 0.044 (2) Å for the O atom. The di-hydro-pyran ring is in a half-chair conformation and the four essentially planar atoms of this ring form a dihedral angle of 4.6 (2)° with the benzo-pyran ring system. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds, forming chains propagating along [010]. In addition, π-π stacking inter-actions, with centroid-centroid distances of 3.902 (2) and 3.908 (2) Å, link the hydrogen-bonded chains into layers parallel to (001).

Crystal structure of [2-({2-[(2-azanidyl-benzyl-idene)amino]-benzyl-idene}amino)-4-chloro-phenol-ato]nickel(II).

The title complex, [Ni(C20H14ClN3O)], with an asymmetrically chloride-appended Schiff base ligand has been synthesized and structurally characterized at 100 K. In the compound, the central nickel(II) ion has a square-planar coordination geometry with N3O donors of the π-conjugated tetra-dentate Schiff base ligand. In the crystal, the complexes are connected into an inversion dimer via an Ni⋯Ni inter-action [3.1753 (5) Å] and a pair of π-π inter-actions [centroid-centroid distance = 3.8416 (16) Å]. The dimers are linked via a C-H⋯Cl hydrogen bond, forming a chain along the c-axis direction. The dimer chains inter-act with each other through π-π inter-actions [centroid-centroid distance = 3.8736 (16) Å], forming a layer expanding parallel to the ac plane.

Crystal structure of N-(2-benzoyl-5-ethynylphen-yl)quinoline-2-carboxamide.

In the title compound, C25H16N2O2, the quinoline ring system is essentially planar, with a maximum deviation of 0.030 (1) Å, and forms a dihedral angle of 20.9 (1)° with benzoyl benzene ring. The unsubstituted phenyl ring forms dihedral angles of 52.7 (1)° with the quinoline ring system and 54.1 (1)° with the ethynyl-substituted benzene ring. The mol-ecule contains an intra-molecular bifurcated N-H⋯(O,N) hydrogen bond, forming S(5) and S(6) rings, which may influence the conformation of the mol-ecule. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into a three-dimensional network. In addition, the three-dimensional structure contains π-π stacking inter-actions, with centroid-centroid distances of 3.695 (1) and 3.751 (1) Å.

3-(4-Chlorobutyl)-3H-indole-5-carbonitrile

In the title compound, C13H12ClN2, the indole moiety and the chloroalkyl substituent are nearly coplanar, making a dihedral angle of 1.27 (10)°. In the crystal, a supramolecular sheet parallel to the ab plane is generated via weak C—H...Cl hydrogen bonds, aromatic π–π stacking [centroid–centroid distances of 3.5563 (13) and 3.6792 (13) Å] and C—H...π interactions.