Sculpting Process Research Articles

Cell-Free Nonequilibrium Assembly for Hierarchical Protein/Peptide Nanopillars.

Cells contain intricate protein nanostructures, but replicating them outside of cells presents challenges. One such example is the vertical fibronectin pillars observed in embryos. Here, we demonstrate the creation of cell-free vertical fibronectin pillar mimics using nonequilibrium self-assembly. Our approach utilizes enzyme-responsive phosphopeptides that assemble into nanotubes. Enzyme action triggers shape changes in peptide assemblies, driving the vertical growth of protein nanopillars into bundles. These bundles, with peptide nanotubes serving as a template to remodel fibronectin, can then recruit collagen, which forms aggregates or bundles depending on their types. Nanopillar formation relies on enzyme-catalyzed nonequilibrium self-assembly and is governed by the concentrations of enzyme, protein, peptide, the structure of the peptide, and peptide assembly morphologies. Cryo-EM reveals unexpected nanotube thinning and packing after dephosphorylation, indicating a complex sculpting process during assembly. Our study demonstrates a cell-free method for constructing intricate, multiprotein nanostructures with directionality and composition.

Interactive Mesh Sculpting with Arbitrary Topologies in Head-Mounted VR Environments

Shape modeling is a dynamic area in computer graphics with significant applications in computer-aided design, animation, architecture, and entertainment. Virtual sculpting, a key paradigm in free-form modeling, has traditionally been performed on desktop computers where users manipulate meshes with controllers and view the models on two-dimensional displays. However, the advent of Extended Reality (XR) technology has ushered in immersive interactive experiences, expanding the possibilities for virtual sculpting across various environments. A real-time virtual sculpting system implemented in a Virtual Reality (VR) setting is introduced in this paper, utilizing quasi-uniform meshes as the foundational structure. In our innovative sculpting system, we design an integrated framework encompassing a surface selection algorithm, mesh optimization technique, mesh deformation strategy, and topology fusion methodology, which are all tailored to meet the needs of the sculpting process. The universal, user-friendly sculpting tools designed to support free-form topology are offered in this system, ensuring that the meshes remain watertight, manifold, and free from self-intersections throughout the sculpting process. The models produced are versatile and suitable for use in diverse fields such as gaming, art, and education. Experimental results confirm the system’s real-time performance and universality, highlighting its user-centric design.

Dental sculpting and compensatory shearing crests demonstrated in a WEAR series of Presbytis rubicunda (Cercopithecoidea, Colobidae) with dental topography analysis.

Maintaining effective and efficient occlusal morphology presents adaptive challenges for mammals, particularly because mastication produces interactions with foods and other materials that alters the geometry of occlusal surfaces through macrowear and/or catastrophic failure (i.e. "chipping"). Altered occlusal morphologies are often less effective for masticating materials of given diet-but not always-some species exhibit dental sculpting, meaning their dentitions are set up to harness macrowear to hone their occlusal surfaces into more effective morphologies (i.e. secondary morphologies). Here we show that dental sculpting is present in the folivorous Presbytis rubicunda of Borneo. Thirty-one undamaged lower second molars of P. rubicunda exhibiting various stages of macroscopic wear were micro-CT scanned and processed into digital surfaces. The surfaces were measured for convex Dirichlet normal energy (vDNE, a measure of surface sharpness), and degree of surface wear. Regression analyses compared surface sharpness with several measures of wear to test for the presence and magnitude of dental sculpting. Positive correlations between the wear proxies and vDNE reveal that P. rubicunda wear in such a way as to become sharper, and therefore more effective chewing surfaces by exposing enamel-dentine junctions on their occlusal surfaces and then honing these junctions into sharpened edges. Compared to another primate folivore in which increasing surface sharpness with macrowear has been demonstrated (i.e., Alouatta palliata), the worn surfaces are similarly sharp, but the dental sculpting process appears to be different. The results presented here suggest that not only do some primates exhibit dental sculpting and the attendant secondary morphology, but that there appear to be multiple different morphological configurations that can achieve this result. P. rubicunda has thicker enamel and a more stereotyped wear pattern than A. palliata, although both show positive correlations of occlusal surface sharpness (vDNE) with various wear proxies. These findings shed light on the varied approaches for the maintenance of effective and efficient occlusal surfaces in primates.

Higher Computed Tomography (CT) Scan Resolution Improves Accuracy of Patient-specific Mandibular Models When Compared to Cadaveric Gold Standard

3D-printed patient-specific anatomical models are becoming an increasingly popular tool for planning reconstructive surgeries to treat oral cancer. Currently there is a lack of information regarding model accuracy, and how the resolution of the computed tomography (CT) scan affects the accuracy of the final model. The primary objective of this study was to determine the CT z-axis resolution necessary in creating a patient specific mandibular model with clinically acceptable accuracy for global bony reconstruction. This study also sought to evaluate the effect of the digital sculpting and 3D printing process on model accuracy. This was a cross-sectional study using cadaveric heads obtained from the Ohio State University Body Donation Program. The first independent variable is CT scan slice thickness of either 0.675, 1.25, 3.00, or 5.00mm. The second independent variable is the three produced models for analysis (unsculpted, digitally sculpted, 3D printed). The degree of accuracy of a model as defined by the root mean square (RMS) value, a measure of a model's discrepancy from its respective cadaveric anatomy. All models were digitally compared to their cadaveric bony anatomy using a metrology surface scan of the dissected mandible. The RMS value of each comparison evaluates the level of discrepancy. One-way ANOVA tests (P<.05) were used to determine statistically significant differences between CT scan resolutions. Two-way ANOVA tests (P<.05) were used to determine statistically significant differences between groups. CT scans acquired for 8 formalin-fixed cadaver heads were processed and analyzed. The RMS for digitally sculpted models decreased as slice thickness decreased, confirming that higher resolution CT scans resulted in statistically more accurate model production when compared to the cadaveric gold standard. Furthermore, digitally sculpted models were significantly more accurate than unsculpted models (P<.05) at each slice thickness. Our study demonstrated that CT scans with slice thicknesses of 3.00mm or smaller created statistically significantly more accurate models than models created from slice thicknesses of 5.00mm. The digital sculpting process statistically significantly increased the accuracy of models and no loss of accuracy through the 3D printing process was observed.

Robust quasi-uniform surface meshing of neuronal morphology using line skeleton-based progressive convolution approximation.

Creating high-quality polygonal meshes which represent the membrane surface of neurons for both visualization and numerical simulation purposes is an important yet nontrivial task, due to their irregular and complicated structures. In this paper, we develop a novel approach of constructing a watertight 3D mesh from the abstract point-and-diameter representation of the given neuronal morphology. The membrane shape of the neuron is reconstructed by progressively deforming an initial sphere with the guidance of the neuronal skeleton, which can be regarded as a digital sculpting process. To efficiently deform the surface, a local mapping is adopted to simulate the animation skinning. As a result, only the vertices within the region of influence (ROI) of the current skeletal position need to be updated. The ROI is determined based on the finite-support convolution kernel, which is convolved along the line skeleton of the neuron to generate a potential field that further smooths the overall surface at both unidirectional and bifurcating regions. Meanwhile, the mesh quality during the entire evolution is always guaranteed by a set of quasi-uniform rules, which split excessively long edges, collapse undersized ones, and adjust vertices within the tangent plane to produce regular triangles. Additionally, the local vertices density on the result mesh is decided by the radius and curvature of neurites to achieve adaptiveness.

Sculpting Electrochemically Growing or Grown Microarchitectures.

Microarchitectures with complex interior structures are important for many applications. However, engineering complex interior structures within microarchitectures are challenging. This article reports the introduction of electrochemical sculpting processes to carve the microarchitectures during or after their electrochemical growing process to design the interior structure of the microarchitectures. The electrochemical growing and sculpting process tangle together under the constant voltage electrodeposition mode with their strength depending on the ion concentration gradient and the voltage value. The unique thawing process of the frozen electrolyte is used to create the desired sharp ion concentration gradient, and has the potential to control the strength of the sculpting and the growing processes. How to completely decouple the growing and the sculpting process is further studied to gain more accurate control over the interior structures of the microarchitectures. It is revealed that the sculpting process can be exclusively applied onto the electrochemically grown microarchitectures simply by reversing the electric field without triggering any growing processes. Microarchitectures with complex interior structures, including micropyramids with a single cavity exclusively at the outward or every apex to multi-walled hollow pyramids with designable wall numbers and inter-wall distances are prepared as examples.

Building a Medical Family: Family Sculpting in Graduate Medical Education

Introduction: Family sculpting has been used as a clinical technique for decades within the psychotherapy community to uncover, process, and improve upon the implicit patterns of interaction and communication that permeate the lives of family members. However, even though this technique has been broadly applied to various couple and family populations within the clinical practice of family therapy, its application has essentially been non-existent outside of this venue.&#x0D; Method: The following article describes the utilization of family sculpting as a bonding technique for a group of family medicine and clinical pharmacy residents, faculty physicians, and upper administration during a yearly organizational retreat.&#x0D; Results: Not only was the technique well received by the healthcare team as a whole, as evidenced by a post retreat survey, there were also several noteworthy examples of the sculpting process highlighting and addressing relational tension within the residency cohort (i.e., second year medical resident) and within administration (i.e., chief executive officer) that ultimately lead to greater team cohesion afterwards.&#x0D; Discussion: While the application of the technique in a medical/educational context can be considered a unique contribution of the article, more so are the specific augmentations made to the technique itself that increases its value as an academic and organizational development tool.

Sensuousness Space: Internalizing Islamic Geometrical Ornament found in National Mosque

This project seeks to identify the fundamental form of Islamic geometrical patterns found in the National Mosque. The internalization from the subject and visit helps to produce an installation sculpture. The sculpting process uses plywood as the primary material and is formed by using mathematical methods and woodworking as the approach. The work presents in installation as it potentially delivers a sense of sacredness towards the audience. Therefore, this study explores the chronology of artmaking inspired by the hidden form and its foundation in Islamic ornament and reviews how its complexity creates a sense of sacredness towards the atmosphere of human psychology. Keywords: Sensuousness Space, Islamic Geometrical Ornament, National Mosque, Installation eISSN: 2398-4287 © 2021. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning &amp; Surveying, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/ebpj.v6iSI6.3042

Exploring Paternal Mentalization Among Fathers of Toddlers Through a Clay-Sculpting Task.

This study explored parental mentalization processes as they unfolded during a sculpting task administered to fathers of toddlers. Parental mentalization—the parent’s ability to understand behavior (his/her own as a parent and that of their child) based on its underlying mental states (Luyten et al., 2017)—is considered crucial within parent–child relationships (Fonagy et al., 1998) and child development (Steele and Steele, 2008). Eleven Israeli first-time fathers (n = 11) of children aged 2–3 (mean = 2.3) were asked to sculpt a representation of themselves with their child using clay. Following the task, the fathers were interviewed while observing the sculpture they had created. Qualitative thematic analysis integrated three types of data—video footage of the sculpting processes, the sculptures themselves, and the transcripts of the post-sculpting interviews. By focusing on data extracts relating to mentalization processes, three main aspects of the clay-sculpting task and interview were identified as processes that either preceded controlled mentalization instances and/or related to their underlying dynamics: (1) discussing the sculpting process elicited the father’s curiosity and wonder; (2) observing the sculpture/sculpting process revealed gaps in paternal representations; and (3) the preplanning of the sculptures sparked non-verbal exploration of metaphors and symbolism. Special attention was given, in the analysis, to the interplay between verbal and non-verbal aspects of mentalization as they appeared in the metaphorical representations that arose through the sculpting process. Comparing this sample to a previous sample of mothers who were given the same task, similarities and differences were explored, with specific reference to topics of embodiment, gender roles, paternity leave, and an active approach in art therapy. The discussion indicates that clay sculpting may offer unique insight into implicit parental mentalization. Possible clinical applications are discussed, with reference to attachment theory and clinical art therapy approaches.

Regenerative medicine of tissue engineering： auricular cartilage regeneration and functional reconstruction

Summary Deformity of the auricle can result from congenital defects, oncologic resection, or traumatic injury. Current clinical strategy is to utilize autologous costal cartilage for reconstructing auricular scaffolds with long-term stability. However, this method is limited by donor-site morbidity, a complex surgical sculpting process, and differing mechanical properties compared to elastic auricular cartilage. Alternatively, alloplastic implants can offer precise shape and avoid donor-site surgery, but suffer from poor biocompatibility and high rates of infection and extrusion. A tissue engineering approach to auricular reconstructions would overcome the limitations of both autologous and alloplastic transplants. In this review we focus on tissue engineering auricular cartilage reconstruction, including auricular seed cells culture and their differentiated control strategy, scaffolds choices and design technique. Many studies found that auricular chondrocytes were the most suitable seed cells to fabricate elastic cartilage; progenitor cells from auricular cartilage could differentiate into elastic chondrocytes, and other types of chondrocytes had its limitation because of the final ossification. Many types of growth factors had the differing potential ability for accelerating chondrocytes growth, differentiation, or maintaining chondrocytes phenotype. Recent advances in tissue engineering auricular cartilage, including several clinic applications, implied that tissue engineering auricules would become a hopefully potential soulution for the future of auricular reconstruction.

Sculptures in Concurrency

We give a formalization of Pratt's intuitive sculpting process for higher-dimensional automata (HDA). Intuitively, an HDA is a sculpture if it can be embedded in (i.e., sculpted from) a single higher dimensional cell (hypercube). A first important result of this paper is that not all HDA can be sculpted, exemplified through several natural acyclic HDA, one being the famous broken box example of van Glabbeek. Moreover, we show that even the natural operation of unfolding is completely unrelated to sculpting, e.g., there are sculptures whose unfoldings cannot be sculpted. We investigate the expressiveness of sculptures, as a proper subclass of HDA, by showing them to be equivalent to regular ST-structures (an event-based counterpart of HDA) and to (regular) Chu spaces over 3 (in their concurrent interpretation given by Pratt). We believe that our results shed new light on the intuitions behind sculpting as a method of modeling concurrent behavior, showing the precise reaches of its expressiveness. Besides expressiveness, we also develop an algorithm to decide whether an HDA can be sculpted. More importantly, we show that sculptures are equivalent to Euclidean cubical complexes (being the geometrical counterpart of our combinatorial definition), which include the popular PV models used for deadlock detection. This exposes a close connection between geometric and combinatorial models for concurrency which may be of use for both areas.

Biology and the beast? The white man’s quest for physical dominance in early twentieth-century America

ABSTRACTDrawing on the relatively nascent world of animal history, the present article seeks to demonstrate how interactions between humans and nonhumans served to both reinforce and destabilise ideas of masculinity within American society. It does so through an examination of three unusual athletic case studies, spanning the period 1893 to 1926. Beginning with Eugen Sandow’s infamous wrestling bout with Commodore the lion, the article goes on to explore the phenomenon of bear wrestling within the American circus before finally discussing John Bauman’s 1923 and 1926 biological experiments pitting man against chimpanzee. Though these athletic contests were unconventional, even by the standards of the day, they served as arenas for predominately white men to display their masculinity. The article thus builds on previous gender and sporting histories, which have viewed physical activity as a means for men to establish their dominance over women and other men during this period. Expanding on this, the article demonstrates the role of nonhumans in this gender sculpting process in the hope of bringing animals even closer to the mainstream.

Modeling the Ecorche Human Figure In Clay

This book is meant for especially those peoples or artists, Namely Sculptors and Painters or Students who are studying human anatomy or Fine Art. As a Sculptor, Netra Khattri has made this book with the language of Art (Sculpture), how muscles attach to the human skeleton, and from where the muscle originates and inserts with muscle function. This book is a dream come true, firstly Netra Khattri saw as human muscles in sculpture terms, then beginning to end not only human bone and muscles but distinct stages: Skeleton, half muscled figure and mainly origin, insertion, and function of muscles too. The reader may come into this process of evolution and metamorphosis at any time, for any kind of specific reference: at the skeleton to see how the bones and muscles are constructed. But there are more interesting facts in human anatomy than here. The difference between this book shows the Ecorche sculpting process in finished anatomical references rather than, other anatomy book shows drawings of muscles attach to bone and structures of human anatomy.

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Images Pascal Schwaighofer Royal Batik It might be risky and somehow shallow to start by saying that the featured artworks "deal" with traces. After all, which artwork does not? Opening a discussion on artifacts by comparing them with traces might lock you up in a mental maze. To put it simply, should we consider traces to be anonymous and mute marks or meaningful signs demanding to be deciphered? Artifacts, indeed, might force you to decide for the latter, but then we might ask: do they really "demand" such a thing? And to complicate it a little bit, one might continue and wonder: do these signs refer to something beyond or "just" to themselves? The main reason I am cautious is my supposition that in this case some of the questions related to traces have become tightly "wrapped" into a form and, instead of unfolding them, it might be more rewarding to contemplate their folded shape. I am saying this not for the sake of mystification or some hermetic détournement, but because sometimes fossilized "wrinkles" get easily spoiled, and the better way to appreciate their untranslatable sinuosity is to keep them "unaltered." To avoid that, therefore, I will refrain from quoting, and try to contain, let's say, theoretical speculations. To start with, Sketches for a Flag (Royal Batik) is one of several outcomes of a longterm project with the overarching title Royal Batik. As the name suggests, it has as its starting point the wax-resist—mainly beeswax—dyeing process called batik. The etymology of the ancient craft reflects its Javanese and Proto-Austronesian roots referring to "writing" or "tattooing," whereas the contemporary word is the result of British and Dutch colonial butchering of the original term. The second work is called La mala mimesis; plaster casts of framed honeycombs. While plaster molding is renowned as the pivotal process that facilitated for centuries—and still does—copying and reproducing forms ad libitum, forcing bees to nest into frames is a practice that allows modern apiculture to exploit these laborious tiny workers also, almost—recent bees' colony collapses rectify—ad libitum. It goes without saying that in both artworks technique and history or, in other words, material culture and politics, meet and mingle; making a thorough "unpacking" difficult. I will attempt, nevertheless, to delve first into the craft, or perhaps the technical aspects. For many centuries plaster models were considered in the Western tradition only for planning, sketches, or transitory processes. Particularly for sculpture, plaster was considered handy either for scale models in the planning phase or as molds for metal casting. Gessoes sculpture allowed the Maestro—usually assisted by a number of anonymous apprentices—to better control the carving process by transposing with pantographs the statue's features and proportions from model to stone. At the end of the nineteenth century, plaster was no longer deemed a poor and transitory material and was elevated to the realm of creativity. Before that shift, however, plaster casting had already been popular among physicians, ethnologists, botanists, and zoologists. Casts of fruits and vegetables, [End Page 122] animals, and body parts—particularly those deformed by pathologies or not complying with "Western" traits—were common pieces of bourgeois and Eurocentric curiosity. The early birds, that is, the artists who introduced the casting of body parts in the sculpting process were at first labeled by their contemporaries as cheaters. Among the detractors, one might find big names such as Charles Baudelaire and Auguste Rodin. If we consider their historical context, it is no surprise that the liberal arts felt the threatening pressure of impressive new technologies. Plaster casting was in fact associated with photography: the latter a menace for painters, the former for sculptors. Having said that, the strong resistance cannot be reduced only to a reaction against technical reproduction and loss of authority. To cut short a long analysis, up to the end of nineteenth century, artistic disputes took place in the borderlines of metaphysical debates between "realists" and "animists." As surprising as it might sound, there is something photographic about batik. By this I mean that phenomenologically speaking it is reminiscent of the photosensitive chemical process. Fabric soaked in wax becomes...

Spatial Correlation: An Interactive Display of Virtual Gesture Sculpture

Abstract Spatial Correlation is an interactive digital artwork that provides a new window into the process of creating freeform handcrafted virtual sculptures while standing in an immersive Cave virtual reality (VR) environment. The piece originates in the lab, where the artist’s full-body, dance-like sculpting process is recorded using a combination of spatial tracking devices and an array of nine synchronized video cameras. Later, in the gallery, these raw data are reinterpreted as part of an interactive visualization that relates the three spaces in which the sculpture exists: 1) the physical lab/studio space in which the sculpture was created, 2) the digital virtual space in which the sculpture is mathematically defined and stored, and 3) the physical gallery space in which viewers now interact with the sculpture.

A real-time virtual sculpting application by using an optimized hash-based octree

sculpting system by using a hash-based octree data structure with an optimized approach to reduce the huge memory and computation cost and also the tree traversal time. The system first reads the selected 3D virtual object model, which must be in a triangular watertight polygon mesh format. Then both the surface and the interior volume of the virtual object is voxelized in order to generate its volumetric dataset. Afterwards, a hash-based data structure with a novel optimized approach is applied to the dataset. After each sculpting process applied to the virtual object, its surface is locally reconstructed and a feedback force is calculated synchronously. Finally, to give the user a realistic sense of interaction, the feedback force is sent back via a haptic device. Creation durations of a traditional octree, a hash-based octree, and our optimized hash-based octree are compared. Tree traversal and surface reconstruction times of our optimized hash-based octree approach are also compared with the pointer-based one in off-line and real-time while sculpting a 3D model. It is shown that the memory requirement and durations of our optimized approach are the lowest.

How Synaptotagmin I, N-BAR and F-BAR Domains Generate Membrane Curvature

Protein-induced membrane curving governs many cellular processes, including cell division, growth and cell-cell communication. In order to unravel the mechanism for how membrane curvature occurs driven by the proteins, one needs to have detailed molecular pictures on the key membrane-protein interactions and protein-protein interactions. Computer simulation serves as a great tool in providing such molecular pictures and thus in rationalizing how proteins curve membrane. For example, it is known that neurotransmitter release involves a Ca++ ion-regulated fusion process between synaptic vesicles and the presynaptic membrane, but little is known for how such small ions function. With the help of computer simulation, we realized the Ca++-sensor protein, synaptotagmin I, undergoes a conformational transition after binding to both the Ca++ and membrane that differs from the membrane-free crystal/NMR structure. The new synaptotagmin conformation has its C-terminal helix to interact with the presynaptic membrane, and thereby, causes the presynaptic membrane to curve and facilitates membrane-vesicle fusion. Another example in showing the power of computer simulation lies in resolving how N-BAR and F-BAR domains sculpt a flat membrane. As these domains form a lattice in the sculpting process, we identified the optimal lattice type and key protein-protein interactions within the lattice. The whole process of membrane tubulation from a flat membrane was resolved from the simulations, and agreements were found between the lattice structures observed via cryo-electron microscopy and the simulations.

Sculpting the UMLS Refined Semantic Network.

BackgroundThe Refined Semantic Network (RSN) for the UMLS was previously introduced to complement the UMLS Semantic Network (SN). The RSN partitions the UMLS Metathesaurus (META) into disjoint groups of concepts. Each such group is semantically uniform. However, the RSN was initially an order of magnitude larger than the SN, which is undesirable since to be useful, a semantic network should be compact. Most semantic types in the RSN represent combinations of semantic types in the UMLS SN. Such a “combination semantic type” is called Intersection Semantic Type (IST). Many ISTs are assigned to very few concepts. Moreover, when reviewing those concepts, many semantic type assignment inconsistencies were found. After correcting those inconsistencies many ISTs, among them some that contradicted UMLS rules, disappeared, which made the RSN smaller.ObjectiveThe authors performed a longitudinal study with the goal of reducing the size of the RSN to become compact. This goal was achieved by correcting inconsistencies and errors in the IST assignments in the UMLS, which additionally helped identify and correct ambiguities, inconsistencies, and errors in source terminologies widely used in the realm of public health.MethodsIn this paper, we discuss the process and steps employed in this longitudinal study and the intermediate results for different stages. The sculpting process includes removing redundant semantic type assignments, expanding semantic type assignments, and removing illegitimate ISTs by auditing ISTs of small extents. However, the emphasis of this paper is not on the auditing methodologies employed during the process, since they were introduced in earlier publications, but on the strategy of employing them in order to transform the RSN into a compact network. For this paper we also performed a comprehensive audit of 168 “small ISTs” in the 2013AA version of the UMLS to finalize the longitudinal study.ResultsOver the years it was found that the editors of the UMLS introduced some new inconsistencies that resulted in the reintroduction of unwarranted ISTs that had already been eliminated as a result of their previous corrections. Because of that, the transformation of the RSN into a compact network covering all necessary categories for the UMLS was slowed down. The corrections suggested by an audit of the 2013AA version of the UMLS achieve a compact RSN of equal magnitude as the UMLS SN. The number of ISTs has been reduced to 336. We also demonstrate how auditing the semantic type assignments of UMLS concepts can expose other modeling errors in the UMLS source terminologies, e.g., SNOMED CT, LOINC, and RxNORM that are important for health informatics. Such errors would otherwise stay hidden.ConclusionsIt is hoped that the UMLS curators will implement all required corrections and use the RSN along with the SN when maintaining and extending the UMLS. When used correctly, the RSN will support the prevention of the accidental introduction of inconsistent semantic type assignments into the UMLS. Furthermore, this way the RSN will support the exposure of other hidden errors and inconsistencies in health informatics terminologies, which are sources of the UMLS. Notably, the development of the RSN materializes the deeper, more refined Semantic Network for the UMLS that its designers envisioned originally but had not implemented.

Sculpting dynamical systems for models of neural computation and memory

Dynamical systems are now a mainstay of computational neuroscience. Persistent activity in biological neural networks has been posited to result from dynamical attractors in neural state-space [1], and computation with attractors underlies a variety of models for information processing and memory function in the brain [2-4]. Nevertheless, there exists no general, substrate-free method for the construction of these dynamical systems [2], substrate-free meaning not tied to a particular neural instantiation. We introduce such a method in this work, with a focus on applications to neural computation and memory modeling. We call this method state-space sculpting. The systems it constructs, or sculpts, are realized as ordinary differential equations. Sculpting is therefore substrate free; it is general in the sense that sculpted systems may contain any number of attractors embedded at any locations in the state-space and the basins of those attractors may be shaped with any smooth geometry. We conjecture that the sculpting process is analogous to learning by synaptic modification in some biological and artificial neural networks. The method works as follows. First, a set of attractor locations and types (fixed point, periodic, strange) is defined. Then a set of corresponding vector fields is identified: Each of these has one of the defined attractor types at one of the defined locations in its state-space. Next, the basins of these attractors are delineated by defining smooth boundaries for the corresponding vector fields. Finally, the set of vector fields and boundaries is unified into a single smooth dynamical equation using regularization [5]. We have sculpted various 2-dimensional systems by this method, and their dynamics were confirmed in simulation to exhibit the defined attractors and basins. These systems contained arbitrary combinations of fixed point and periodic attractors, as well as repelling regions, with arbitrary basin geometries. Systems of saddle equilibria were also sculpted to demonstrate the versatility of the method. These can be made to exhibit heteroclinic channels and cycles, which are key features of the Winnerless Competition Principle of neural computation [4]. As a first test of our conjecture on the analogy between sculpting and synaptic modification, the well known Hopfield network [6] was analyzed and characterized in sculpting terms. This analysis demonstrated most notably that the network's basins of attraction are delineated by combinations of codimension-1 hyperplanes containing saddle equilibria. The analogue of state-space sculpting in the Hopfield network is therefore limited, since attractor basins cannot be shaped with any smooth geometry. Moving forward, it is necessary to study more complicated networks to show that they can be cast in the sculpting framework, as well as to extend the sculpting method to higher-dimensional state-spaces and manifolds.

Controllable Atomic Scale Patterning of Freestanding Monolayer Graphene at Elevated Temperature

We show that by operating a scanning transmission electron microscope (STEM) with a 0.1 nm 300 kV electron beam, one can sculpt free-standing monolayer graphene with close-to-atomic precision at 600 °C. The same electron beam that is used for destructive sculpting can be used to image the sculpted monolayer graphene nondestructively. For imaging, a scanning dwell time is used that is about 1000 times shorter than for the sculpting. This approach allows for instantaneous switching between sculpting and imaging and thus fine-tuning the shape of the sculpted lattice. Furthermore, the sculpting process can be automated using a script. In this way, free-standing monolayer graphene can be controllably sculpted into patterns that are predefined in position, size, and orientation while maintaining defect-free crystallinity of the adjacent lattice. The sculpting and imaging processes can be fully computer-controlled to fabricate complex assemblies of ribbons or other shapes.