Linkage Assembly Research Articles

The effect of mountain-valley folds on the rigid foldability of double corrugated pattern

Origami is able to create a 3D sculpture by folding a piece of paper by following the crease lines, which can be mountain or valley folds. Rigid origami is a subset of origami in which the panels, that are surrounded with the creases, do not stretch or bend during its folding sequence, but only rotate about the creases. Besides geometric design parameters, the mountain-valley fold assignments also affect the rigid-foldability of origami patterns. This paper proposes a general kinematic method to analyze the rigid-foldability of origami patterns by modelling them as assemblies of spherical linkages. The double corrugated pattern is taken as the study case. We first investigate the rigid-foldability of all possible mountain-valley fold assignments that can satisfy the condition of flat-foldability. Subsequently, we explore different rigid-foldable tessellations of the double corrugated patterns. This work will offer an in-depth understanding of the effect of mountain-valley folds on the rigid-foldability of origami patterns.

Mobile assemblies of Bennett linkages from four-crease origami patterns.

This paper deals with constructing mobile assemblies of Bennett linkages inspired by four-crease origami patterns. A transition technique has been proposed by taking the thick-panel form of an origami pattern as an intermediate bridge. A zero-thickness rigid origami pattern and its thick-panel form share the same sector angles and folding behaviours, while the thick-panel origami and the mobile assembly of linkages are kinematically equivalent with differences only in link profiles. Applying this transition technique to typical four-crease origami patterns, we have found that the Miura-ori and graded Miura-ori patterns lead to assemblies of Bennett linkages with identical link lengths. The supplementary-type origami patterns with different mountain-valley crease assignments correspond to different types of Bennett linkage assemblies with negative link lengths. And the identical linkage-type origami pattern generates a new mobile assembly. Hence, the transition technique offers a novel approach to constructing mobile assemblies of spatial linkages from origami patterns.

Deployable Prismatic Structures With Rigid Origami Patterns

Rigid origami inspires new design technology in deployable structures with large deployable ratio due to the property of flat foldability. In this paper, we present a general kinematic model of rigid origami pattern and obtain a family of deployable prismatic structures. Basically, a four-crease vertex rigid origami pattern can be presented as a spherical 4R linkage, and the multivertex patterns are the assemblies of spherical linkages. Thus, this prismatic origami structure is modeled as a closed loop of spherical 4R linkages, which includes all the possible prismatic deployable structures consisting of quadrilateral facets and four-crease vertices. By solving the compatibility of the kinematic model, a new group of 2n-sided deployable prismatic structures with plane symmetric intersections is derived with multilayer, straight and curvy variations. The general design method for the 2n-sided multilayer deployable prismatic structures is proposed. All the deployable structures constructed with this method have single degree-of-freedom (DOF), can be deployed and folded without stretching or twisting the facets, and have the compactly flat-folded configuration, which makes it to have great potential in engineering applications.

Web Content Mining equipped Natural Language Processing for handling web data

The growing usage of the web has unfolded the Web mining technology to a great extent. Web mining helps in extraction of useful knowledge from web data. (i.e. a range of web pages, hyperlinks among various pages, web sites usage logs and so on. This paper has threefold aspect. Firstly, it defines how web mining research area focuses on mining research and retrieval research (i.e. retrieval of data, information on web, data and text mining). Secondly, it categorizes the Web mining as content mining (i.e. retrieval of information from texts, images and other contents), structure mining (i.e. finding of facts from association of web pages) and usage mining (i.e. mining of information about usage of web sites). Web content mining mainly focuses on the structure of inner-document whereas web structure mining aim is to discover the linkage assembly of the hyperlinks at the inter-document level. Web usage mining includes three major phases i.e. preprocessing, pattern discovery and pattern analysis. Thirdly, it focuses on natural language processing as a backbone for web content mining that helps in handling of unstructured data over the web by offering various techniques. This paper concluded the web mining as trending research area for various research communities such as Databases, Artificial intelligence, Information retrieval and E-commerce.

A new method of QTL identification for undersaturated maps.

In many species, low levels of polymorphism prevent the assembly of linkage maps that are used to identify genetic markers related to the expression of quantitative trait loci (QTLs). This study compared two methods of locating QTLs in association studies that do not require a previous estimation of linkage maps. Method I (MI) was a Bayesian multiple marker regression and Method II (MII) combined multiple QTL mapping and "moving away from markers". In this method, markers are not directly regressed to the phenotype, but are used as pivots to search for QTLs along the genome. To compare methods, we simulated 300 individuals from an F2 progeny with two levels of marker loss (20 and 80%). A total of 165 markers and seven QTLs were spread along 11 chromosomes (roughly emulating the genetic structure of the common bean, Phaseolus vulgaris). A real data example with 186 progenies of a F2:4 generation of the species was analyzed using 59 markers (17 simple sequence repeats, 31 amplified fragment length polymorphisms, and 11 sequence-related amplified polymorphisms). MII was more precise than MI for both levels of marker loss. For real data, MII detected 17 candidate positions for QTLs, whereas MI did not detect any. MII is a powerful method that requires further studies with actual data and other designs such as crossover, and genome-wide studies.

Control method for centering rolls in radial-axial ring rolling process

The control method of centering rolls was developed to ensure the circularity of rings and remove the process instability during a radial-axial ring rolling (RARR) process. The position control method is determined by the growth velocity of rolling rings and mathematical correlations among the key process variables, such as ring geometries, roll shapes, and feed rates of rolls. The moving coordinate of centering rolls were calculated by the growing velocity of an outer radius of the ring, VR, and the angle between the links of the ring’s center with the mandrel’s center and with the centering roll’s center, a, in the RARR process. The growth behavior of a ring and the angle provided moving coordinates for the centering rolls in real time. The hydraulic adjustment mechanism for establishing a successful RARR process is also proposed using the parameter design of the linkage assembly and beam bending theory. In order to verify the reliability of the control method, the FE-simulation under a FORGE software environment and ring rolling experiments of 42CrMo4 rings with an outer diameter of 510mm. The results show that these methods provided a high ring circularity and process stability.

Identifying links between origami and compliant mechanisms

Abstract. Origami is the art of folding paper. In the context of engineering, orimimetics is the application of folding to solve problems. Kinetic origami behavior can be modeled with the pseudo-rigid-body model since the origami are compliant mechanisms. These compliant mechanisms, when having a flat initial state and motion emerging out of the fabrication plane, are classified as lamina emergent mechanisms (LEMs). To demonstrate the feasibility of identifying links between origami and compliant mechanism analysis and design methods, four flat folding paper mechanisms are presented with their corresponding kinematic and graph models. Principles from graph theory are used to abstract the mechanisms to show them as coupled, or inter-connected, mechanisms. It is anticipated that this work lays a foundation for exploring methods for LEM synthesis based on the analogy between flat-folding origami models and linkage assembly.

An ankyrin-repeat ubiquitin-binding domain determines TRABID's specificity for atypical ubiquitin chains

Eight different types of ubiquitin (Ub) linkages are present in eukaryotic cells that regulate diverse biological processes. Proteins that mediate specific assembly and disassembly of atypical Lys6, Lys27, Lys29 and Lys33 linkages are largely unknown. We here reveal how the human Ovarian Tumor (OTU) domain deubiquitinase (DUB) TRABID specifically hydrolyzes both Lys29- and Lys33-linked diubiquitin (diUb). A crystal structure of the extended catalytic domain reveals an unpredicted Ankyrin repeat (Ank) domain that precedes an A20-like catalytic core. NMR analysis identifies the Ank domain as a new Ub binding fold termed AnkUBD, and DUB assays in vitro and in vivo show that this domain is crucial for TRABID efficiency and linkage-specificity. Our data are consistent with a role of the AnkUBD as an enzymatic S1' Ub binding site, which orients a Ub chain such that Lys29 and Lys33 linkages are cleaved preferentially.

ChemInform Abstract: Recent Trends in Regioselective Protection and Deprotection of Monosaccharides

AbstractReview: 69 refs.

Recent Trends in Regioselective Protection and Deprotection of Monosaccharides

Abstract: Carbohydrates are complex and structurally diverse compounds in nature with key roles in a broad range of life processes, including signal transduction, carcinogenesis and immune responses. Many natural products contain oligosaccharides that are vital for their biological activity. However, the synthesis of complex oligosaccharides and other glycoconjugates is hampered by difficulties associated with the regioselective protection of polyhydroxyls and challenges related to the stereoselective assembly of glycosidic linkages. Therefore, a big challenge in glycochemistry is to have selectively protected monosaccharide units, one with a strategically positioned free hydroxy group (a nucleophilic acceptor for further glycosylation or functional-group modifications) and suitable protecting groups on the remaining hydroxyls.

Samuel Johnson as Intertextual Critic

Intertextuality considered in its simplest form refers to a silent, invisible assembly of linkages between individual texts, linkages based upon such properties of resemblance as repetition, formal similitude, generic affiliation, semantic identity, reversal, and assimilation and substitution.1 Pragmatically, the notion of intertextuality urges critical readers to focus upon the relationships between texts with an equal or greater attentiveness than what is frequently given to the formal, biographical, or historical properties of literature. Intertextuality can be considered positively or negatively. Positively, it represents an interlocking grid of connection, representing filiations of human contact. This perspective sees the course of literary history as a continuous line in which all texts are aspects of the same ontological order, intact and inclusive. The concept can also bear the negative weight of divisiveness and agonistic conflict of dangerous theft. In the pages to come, both of these aspects will be examined. This paper seeks to interrogate Johnson's critical outlook through the frame of an intertextual perspective.2 More specifically, this essay focuses on two key concepts central to Johnson's literary and critical achievement: mentoring and intertextuality. It aims to realize three specific goals: 1) to establish Johnson's status as a major intertextual critic; 2) to delve more deeply than others have done into Johnson's use of mottos and translations from the periodical essays especially investigating their utility as instruments of critical investigation and illumination;3 and 3) to inquire into the relationship between Johnson's intertextual practice and his lifelong preoccupation with mentoring.4 The essay thus endeavors to connect Johnson's critical practice with recent theoretical notions about interactive and transformative relations among texts, arguing that a consideration of

Apparatus and method for creating acoustic energy in a receiver assembly with improved diaphragms-linkage arrangement

A receiver assembly includes a first diaphragm assembly having a diaphragm, and a second diaphragm assembly having a diaphragm. A linkage assembly is coupled to an armature of the receiver. The linkage assembly is also coupled to the first diaphragm assembly and to the second diaphragm assembly.

A control method of guide rolls in 3D-FE simulation of ring rolling

3D-FE simulation has become an indispensable approach to develop advanced ring rolling technologies, and a perfect 3D-FE ring rolling model is the basic demand of the simulation. How to control the movement of guide rolls reasonably in the model is one of the key problems urgently to be solved, particularly for rings complicated in shape or large in dimension or with high precision. In this paper, a method to control the guide rolls by the hydraulic adjustment mechanism is explored and realized in 3D-FE ring rolling model for the first time, and the key technologies, such as the parameter design of the linkage assembly and critical pressure of the hydraulic ram, are also proposed. Moreover, the difficulty in determining the liquid flow rate out of the hydraulic ram is solved by combining dichotomy with numerical simulation results. Based on the elastic–plastic dynamic finite element method under the ABAQUS software environment, the 3D-FE cold ring rolling model with hydraulic adjustment mechanism has been built, and the side spread of rectangular-section rings and the final section configuration of T-shaped ring have been analyzed. Good agreements between the calculating results and experimental ones prove the validity of the improved cold ring rolling model, and consequently the developed guide roll control method is also valid. Meanwhile, the circularity and oscillation of ring show that the rings are kept circular and stable very well during the process. Therefore the guide roll control method developed is suitable and reliable, particularly for rings complicated in shape or large in dimension or with high precision.

Regioselective one-pot protection of carbohydrates

Carbohydrates are involved in a wide range of biological processes. These structurally diverse compounds are more complex than other biological polymers, and are often present as heterogeneous mixtures in nature. The chemical synthesis of carbohydrates is one way to obtain pure oligosaccharides, but it is hampered by difficulties associated with the regioselective protection of polyhydroxyls and challenges related to the stereoselective assembly of glycosidic linkages. Here we describe a combinatorial, and highly-regioselective, method that can be used to protect individual hydroxy groups of a monosaccharide. This approach can be used to install an orthogonal protecting group pattern in a single reaction vessel (a 'one-pot' reaction), which removes the need to carry out the time-consuming isolation and purification of intermediates. Hundreds of building blocks have been efficiently prepared starting from d-glucose, and the iterative coupling of these building blocks enabled us to assemble beta-1,6-glucans and a library of oligosaccharides based on the influenza-virus-binding trisaccharide.

Crystal structure of CTP:glycerol-3-phosphate cytidylyltransferase from Staphylococcus aureus: Examination of structural basis for kinetic mechanism

Integrity of the cell wall is essential for bacterial survival, and as a consequence components involved in its biosynthesis can potentially be exploited as targets for antibiotics. One such potential target is CTP:glycerol-3-phosphate cytidylyltransferase. This enzyme (TarD Sa in Staphylococcus aureus and TagD Bs in Bacillus subtilis) catalyzes the formation of CDP-glycerol, which is used for the assembly of linkages between peptidoglycan and teichoic acid polymer in Gram-positive bacteria. Intriguingly, despite the high sequence identity between TarD Sa and TagD Bs (69% identity), kinetic studies show that these two enzymes differ markedly in their kinetic mechanism and activity. To examine the basis for the disparate enzymological properties, we have determined the crystal structure of TarD Sa in the apo state to 3 Å resolution, and performed equilibrium sedimentation analysis. Comparison of the structure with that of CTP- and CDP-glycerol-bound TagD Bs crystal structures reveals that the overall structure of TarD Sa is essentially the same as that of TagD Bs , except in the C-terminus, where it forms a helix in TagD Bs but is disordered in the apo TarD Sa structure. In addition, TarD Sa can exist both as a tetramer and as a dimer, unlike TagD Bs , which is a dimer. These observations shed light on the structural basis for the differing kinetic characteristics between TarD Sa and TagD Bs .

Development of a Biaxial Cyclic Stretching Mechanism and Its Use for the Analysis of Mechanical Response of Vascular Endothelial Cells

Study on the cellular responses to biaxial cyclic stretch requires a complex device giving two dimensional deformations to cell substrates. To carry out the biaxial testing easily, we have developed a mechanism that makes a conventional uniaxial device to biaxial one. By incorporating two three-bar linkages into a conventional uniaxial device NS-300, we obtained cyclic stretching motion perpendicular to its original stretch direction. Difference in the displacement between the two directions was less than 1.4% for a 10% stretching mode. By changing the linkage assembly, we can select two modes of biaxial stretching : simultaneous and alternate. The deformation of the silicone membrane on the bottom of a newly developed biaxial chamber was almost uniform in the central region of 12mm×12mm. We applied various modes of biaxial and uniaxial cyclic stretches to bovine aortic endothelial cells with this device, and found that the cells aligned in the direction with minimal substrate deformation, a well-known cellular response to cyclic stretch. This device is useful in studying cellular response to biaxial stretching for its easiness in extending capability of conventional uniaxial stretch devices to biaxial ones.

Synthesis and characterization of asymmetric o- and m-nitrobenzoic acids with a 1,3-benzodioxole skeleton

Asymmetric o- and m-nitrobenzoic acids with a 1,3-benzodioxole skeleton have been synthesized and characterized. The synthesis involved nitration at either the C-5 or C-6 position of 2- tert-butyl-2-methyl-1,3-benzodioxole-4-carboxylate derived from catechol. These were then resolved with chiral solid-phased HPLC columns into each of enantiomers (>99% ee), which were characterized by circular dichroism. The ( S)-enantiomers were also obtained by fractional crystallization of the precursor prior to the nitration. When applied as chiral derivation agents for alcohols and amines, m-nitrobenzoic acid showed notable ability to separate the enantiomers in both HPLC and NMR analyses. On the other hand, 1H NMR and X-ray data of their ester and amide derivatives strongly suggested that the o-nitrobenzoic acid would serve as a fluorescent building block useful for the assembly of β-peptide linkages with a defined conformation.

Convergent assembly of aldol linkages. A study of the stereoselective nitrile oxide cycloaddition reaction

The aldol equivalency of a stereoselective nitrile oxide cycloaddition is exploited in the development of a general synthetic strategy to the polyene macrolide antibiotics.

Desmoplakin is required early in development for assembly of desmosomes and cytoskeletal linkage.

Desmosomes first assemble in the E3.5 mouse trophectoderm, concomitant with establishment of epithelial polarity and appearance of a blastocoel cavity. Throughout development, they increase in size and number and are especially abundant in epidermis and heart muscle. Desmosomes mediate cell-cell adhesion through desmosomal cadherins, which differ from classical cadherins in their attachments to intermediate filaments (IFs), rather than actin filaments. Of the proteins implicated in making this IF connection, only desmoplakin (DP) is both exclusive to and ubiquitous among desmosomes. To explore its function and importance to tissue integrity, we ablated the desmoplakin gene. Homozygous -/- mutant embryos proceeded through implantation, but did not survive beyond E6.5. Surprisingly, analysis of these embryos revealed a critical role for desmoplakin not only in anchoring IFs to desmosomes, but also in desmosome assembly and/or stabilization. This finding not only unveiled a new function for desmoplakin, but also provided the first opportunity to explore desmosome function during embryogenesis. While a blastocoel cavity formed and epithelial cell polarity was at least partially established in the DP (-/-) embryos, the paucity of desmosomal cell-cell junctions severely affected the modeling of tissue architecture and shaping of the early embryo.

Application of RAPD-PCR Markers for Identification and Genetic Analysis of American Elm (Ulmus americana L.) Selections

Abstract We used randomly amplified polymorphic DNA (RAPD) markers from DNA polymerase chain reactions to differentiate selected American elms. DNA profiles made from leaf DNAs of parental trees were identical to profiles produced by DNA from leaves, roots, vascular tissues, callus or suspension-cultured cells from the same trees or their ramets. In addition, several variations in the technique did not appear to alter the genotype-specific DNA profiles from a given elm selection. RAPD polymorphisms were inherited as dominant Mendelian factors in the progeny of a cross between two American elm selections. We conclude that the construction of RAPD DNA profiles is a reliable and easy method for selection identification, genetic analysis, and the assembly of linkage maps in American elms.