This book focuses on a few of the most important clustering algorithms, providing a detailed account of these major models in an information retrieval context. The beginning chapters introduce the ...classic algorithms in detail, while the later chapters describe clustering through divergences and show recent research for more advanced audiences.
Objectives:
The acetabular sourcil has been thought of as the radiographic representation of the weightbearing dome of the acetabulum; however, there are limited modern data to support this ...supposition. In the literature, assessment of weightbearing acetabular coverage has been described using both the sourcil-edge and bone-edge as anatomic landmarks, leading to confusion and controversy in classification of hip dysplasia, indications for hip preservation surgery, and intraoperative coverage assessment. The purpose of this study was to localize the three-dimensional (3D) anatomic correlates of the sourcil-edge and bone-edge radiographic position on false profile radiographs. The authors hypothesized that the sourcil-edge on the false profile represents anterolateral coverage while the bone-edge represents anterior coverage.
Methods:
Forty hips were grouped by large or small differences between bone-edge and sourcil-edge anterior center edge angles (ACEA). The small difference group comprised the lowest quartile of sourcil-edge to bone-edge difference of an initial cohort of 80 hips, while the large difference group comprised the highest quartile of difference. 3D surface mesh models and digitally reconstructed radiographs (DRRs) were generated from hip computed tomography scans using the 3D Slicer Image Computing Platform (Figures 1 & 3). Sourcil-edge, bone-edge, and ACEAs were identified on DRRs and registered to the 3D models with fiducial markers. Intersection of bone-edge and sourcil-edge projection lines with the acetabular rim were obtained from the 3D models (Figures 2 & 4). 3D Anterior acetabular rim morphology was correlated with ACEA difference.
Results:
The bone-edge and sourcil-edge projections intersected the acetabular rim at a mean of 2:08 ± 0:25 and 1:20 ± 0:24 o’clock, respectively. The 3D models consistently demonstrated that, in both large and small discrepancy groups, the sourcil-edge corresponded to an area just posterior to the AIIS projection while the bone-edge corresponded to the weight-bearing region inferior to the AIIS (Figures 2 & 4). Additionally, in large discrepancy hips, the bone-edge corresponded to a more prominent acetabular coverage in the region of the AIIS than when compared to the small discrepancy hips.
Conclusions:
This study demonstrates that both the sourcil-edge and bone-edge projections on false profile radiographs correlate with differing weightbearing regions of the acetabulum. The sourcil-edge ACEA represents coverage at 1:20 o’clock on the acetabular rim and is consistently posterior to the AIIS, while the bone-edge measurement represents the region of the acetabular rim at 2:08 o’clock and is consistently inferior to the AIIS. In hips with a large discrepancy between bone-edge and sourcil-edge (highest quartile), ACEA measurement differs by a mean of 19.7 degrees based on the selection of these radiographic landmarks. These findings have substantial implications for hip preservation surgery technique and clinical decision making.
A comprehensive understanding of femoral head coverage is essential for the treatment of young adult hip pathology. Although the sourcil and bone edge are two of the most important radiographic landmarks for assessment of acetabular dysplasia, descriptions of these landmarks are often over simplified. Some authors have advocated for greater utilization of measurements of coverage to the bone edge as it can be more consistently identified. Other authors have advocated for utilizing the sourcil-edge measurement as this is more representative of the “weight bearing dome”. These descriptions are limited as they do not improve our understanding of the anatomic and radiographic structure of the anterior acetabular rim. Although the concept of the “weight bearing dome” is classically described, it lacks anatomic precision.
The present study clarifies the anatomic features of the acetabular rim that correspond to these radiographic features. Increased difference between the sourcil-edge and bone edge is generated by the differences in undulation of the anterosuperior acetabular rim. Acetabuli that have maximal anterior rim prominence at or near the superior-most aspect of the acetabulum (generally counterclockwise from the AIIS) tend to demonstrate smaller discrepancy between the bone-edge and sourcil-edge (Figure 4). Acetabuli that have maximal rim prominence medial and anterior to the superior-most aspect of the acetabulum generally demonstrate larger discrepancy (Figure 2). The present anatomic description can be utilized by the hip arthroscopist to better determine which areas of the anterior rim may cause impingement. Similarly, while conducting a periacetabular osteotomy, the surgeon may use this information to better understand how acetabular rotation is contributing to both anterior and anterolateral coverage.
In conclusion, on false profile radiographs, the sourcil-edge corresponds to superior femoral head coverage, while the bone-edge corresponds to anterosuperior coverage. False profile radiographs with a large discrepancy between sourcil-edge and bone-edge measurements demonstrate a prominent weight bearing surface in the region of the AIIS. These data regarding the radiographic phenomena of the acetabular rim can aid in clinical decision-making and intraoperative technique.
Heterogeneity is regarded as the major factor leading to the poor outcomes of glioblastoma (GBM) patients. However, conventional two‐dimensional (2D) analysis methods, such as immunohistochemistry ...and immunofluorescence, have limited capacity to reveal GBM spatial heterogeneity. Thus, we sought to develop an effective analysis strategy to increase the understanding of GBM spatial heterogeneity. Here, 2D and three‐dimensional (3D) analysis methods were compared for the examination of cell morphology, cell distribution and large intact structures, and both types of methods were employed to dissect GBM spatial heterogeneity. The results showed that 2D assays showed only cross‐sections of specimens but provided a full view. To visualize intact GBM specimens in 3D without sectioning, the optical tissue clearing methods CUBIC and iDISCO+ were used to clear opaque specimens so that they would become more transparent, after which the specimens were imaged with a two‐photon microscope. The 3D analysis methods showed specimens at a large spatial scale at cell‐level resolution and had overwhelming advantages in comparison to the 2D methods. Furthermore, in 3D, heterogeneity in terms of cell stemness, the microvasculature, and immune cell infiltration within GBM was comprehensively observed and analysed. Overall, we propose that 2D and 3D analysis methods should be combined to provide much greater detail to increase the understanding of GBM spatial heterogeneity.
Heterogeneity is regarded as the major factor leading to the poor outcomes of glioblastoma (GBM) patients. This study aimed at developing an effective analysis strategy to increase the understanding of GBM spatial heterogeneity. Two‐dimensional (2D) and three‐dimensional (3D) analysis methods were compared for the examination of cell morphology, cell distribution and large intact structures, and both types of methods were employed to dissect GBM spatial heterogeneity. 2D assays showed only cross‐sections of specimens but provided a full view whereas the 3D analysis showed specimens at a large spatial scale at cell‐level resolution and had overwhelming advantages in comparison to the 2D methods. Thus, 2D and 3D analysis methods should be combined to provide much greater detail to increase the understanding of GBM spatial heterogeneity.
Category:
Midfoot/Forefoot; Bunion
Introduction/Purpose:
The pathology of the bunion deformity consists of deformities in the axial, coronal, and sagittal planes of the first metatarsal and its ...articular surface with the medial cuneiform. While weightbearing radiographs have been utilized for assessment of these deformities, such methods have limitations with regard to image magnification, patient position, and superimposition of bone alignments. With advances with weightbearing computed tomography (WBCT), evaluation of the 3- dimensional components of the first metatarsal along with its proximal articular surface can be assessed with greater precision.
This study aims to observe the effect of the midshaft osteotomy on the alignment of the tarsometatarsal joint in three dimension
Methods:
Ten feet in 10 subjects underwent midshaft first metatarsal osteotomies. Weight-bearing (using a load equivalent to body weight) CT scans with .3mm cubic voxel size using an original loading device preoperatively and postoperatively were collected from each of the subjects in neutral standing position. Scans were segmented, and 3D renderings of the medial cuneiform, first metatarsal, and the first phalanx were also generated from the segmentations followed by definition of reference frames to evaluate changes in the metatarsal in relationship to the medial cuneiform. (Fig.1)
Results:
The measurements of the rotational parameters showed greater changes in the sagittal plane postoperatively with dorsiflexion of the first metatarsal relative to the medial cuneiform at the first tarsometatarsal joint (p<0.05).(Fig.2) Post-operative changes in the coronal plane and axial plane with relationship of the first metatarsal to the medial cuneiform were noted. Distance mapping showed a significant increase in surface-to-surface distance at the dorsal tarsometatarsal joint post-operatively with a reduced distance at the inferior portion of the tarsometatarsal joint. (Fig.3).
Conclusion:
Based on the results of the study, midshaft osteotomies of first metatarsal can cause increased dorsiflexion in the sagittal plane, significant eversion in the coronal plane, and external rotation in the axial plane at the tarsometatarsal joint.
Distance mapping analysis on WBCT images identified differences in surface-to-surface interaction of the first metatarsal and the medial cuneiform
Summary
Plants have served as sources providing humans with metabolites for food and nutrition, biomaterials for living, and treatment for pain and disease. Plants produce a huge array of ...metabolites, with an immense diversity at both the population and individual levels. Dissection of the genetic bases for metabolic diversity has attracted increasing research attention. The concept of genome‐wide association study (GWAS) was extended to studies on the diversity of plant metabolome that benefitted from the development of mass‐spectrometry‐based analytical systems and genome sequencing technologies. Metabolic genome‐wide association study (mGWAS) is one of the most powerful tools for global identification of genetic determinants for diversity of plant metabolism. Recently, mGWAS has been performed for various species with continuous improvements, providing deeper insights into the genetic bases of metabolic diversity. In this review, we discuss fully the achievements to date and remaining challenges that are associated with both mGWAS and mGWAS‐based multi‐dimensional analysis. We begin with a summary of GWAS and its development based on statistical methods and populations. As variation in targeted traits is essential for GWAS, we review metabolic diversity and its rise at both the population and individual levels. Subsequently, the application of mGWAS for plants and its corresponding achievements are fully discussed. We address the current knowledge on mGWAS‐based multi‐dimensional analysis and emerging insights into the diversity of metabolism.
Significance Statement
In this review, we highlight some recent progress in the dissection of metabolic diversity, with an emphasis on metabolic genome‐wide association study (mGWAS) and mGWAS‐based multi‐dimensional analysis.
Category:
Hindfoot; Midfoot/Forefoot
Introduction/Purpose:
The cavovarus deformity of Charcot-Marie-Tooth (CMT) disease typically presents with hindfoot varus and forefoot valgus. This seemingly ...paradoxical relationship is poorly understood. Better insight into this complex three- dimensional alignment under physiologic load-bearing conditions is possible using weight-bearing computed tomography (WBCT). This is the first study to examine the extreme rotational deformity in the midfoot of CMT patients, and thereby provides a key to the successful operative correction of the CMT cavovarus foot.
Methods:
We retrospectively reviewed the WBCTs of patients with CMT who presented to a single surgeon. Those with history of bony surgical correction, severe degenerative joint disease, or open physes in the foot, were excluded. Scans were analyzed using three-dimensional analysis software (Disior Bonelogic) to generate axes of select bones and their relationship relative to the tibial plafond anterior-posterior axis in the axial plane. The coronal alignment of the foot involved angular measurements of the calcaneus, talar dome, midfoot and forefoot relative to the ground. We reported quantitative alignment parameters and compared the measurements to WBCT of 20 controls.
Results:
17 WBCT scans from 15 CMT patients (average age 24 years) met criteria for inclusion. In the axial plane, external rotation of the distal tibia accounted for the varus heel position rather than subtalar malalignment. The greatest change in axial alignment occurred between the talar neck and navicular (26 degrees). The average talonavicular (TN) medial uncoverage angle was -15 degrees for CMT patients, indicating medial overcoverage, compared to +11 degrees for controls, (p<0.01). Coronal plane analysis revealed varus rotational deformity at the calcaneus (23 degrees), a peak of 61 degrees varus across the navicular and cuboid, then compensatory rotation of the cuneiforms and metatarsals to achieve a plantigrade forefoot (11 degrees varus). In comparison, controls averaged 9 degrees coronal valgus at the calcaneus and 34 degrees varus at the naviculo-cuboid level, (p<0.01). Figure 1 shows the WBCT scans of a representative CMT patient and control case.
Conclusion:
This three-dimensional WBCT analysis is the first to characterize and quantify the axial and coronal rotational deformity in CMT. Axial plane deformity had a center of rotational angulation at the talonavicular joint, associated with medial ’overcoverage’ of the talar head, likely from chronic tibialis posterior over-pull. The peak coronal deformity was localized at the navicular and cuboid, which measured nearly twice as much as controls. These observations suggest dorsiflexion osteotomy of the 1st metatarsal would fail to address the coronal rotation; releases through the talonavicular joint may be necessary to abduct and de-rotate the midfoot to achieve a plantigrade foot.
Cake layer formation is the dominant ultrafiltration membrane fouling mechanism after long-term operation. However, precisely analyzing the cake-layer structure still remains a challenge due to its ...thinness (micro/nano scale). Herein, based on the excellent depth-resolution and foulant-discrimination of time-of-flight secondary ion mass spectrometry, a three-dimensional analysis of the cake-layer structure caused by natural organic matter was achieved at lower nanoscale for the first time. When humic substances or polysaccharides coexisted with proteins separately, a homogeneous cake layer was formed due to their interactions. Consequently, membrane fouling resistances induced by proteins were reduced by humic substances or polysaccharides, leading to a high flux. However, when humic substances and polysaccharides coexisted, a sandwich-like cake layer was formed owing to the asynchronous deposition based on molecular dynamics simulations. As a result, membrane fouling resistances were superimposed, and the flux was low. Furthermore, it is interesting that cake-layer structures were relatively stable under common UF operating conditions (i.e., concentration and stirring). These findings better elucidate membrane fouling mechanisms of different natural-organic-matter mixtures. Moreover, it is demonstrated that membrane fouling seems lower with a more homogeneous cake layer, and humic substances or polysaccharides play a critical role. Therefore, regulating the cake-layer structure by feed pretreatment scientifically based on proven mechanisms should be an efficient membrane-fouling-control strategy.
We provide a systematic and self-consistent method to calculate the generalized Brillouin zone (GBZ) analytically in one-dimensional non-Hermitian systems, which helps us to understand the ...non-Hermitian bulk-boundary correspondence. In general, a n-band non-Hermitian Hamiltonian is constituted by n distinct sub-GBZs, each of which is a piecewise analytic closed loop. Based on the concept of resultant, we can show that all the analytic properties of the GBZ can be characterized by an algebraic equation, the solution of which in the complex plane is dubbed as auxiliary GBZ (aGBZ). We also provide a systematic method to obtain the GBZ from aGBZ. Two physical applications are also discussed. Our method provides an analytic approach to the spectral problem of open boundary non-Hermitian systems in the thermodynamic limit.
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