Anchor Segments Research Articles

Two-stage lesion detection approach based on dimension-decomposition and 3D context

Lesion detection in Computed Tomography (CT) images is a challenging task in the field of computer-aided diagnosis. An important issue is to locate the area of lesion accurately. As a branch of Convolutional Neural Networks (CNNs), 3D Context-Enhanced (3DCE) frameworks are designed to detect lesions on CT scans. The False Positives (FPs) detected in 3DCE frameworks are usually caused by inaccurate region proposals, which slow down the inference time. To solve the above problems, a new method is proposed, a dimension-decomposition region proposal network is integrated into 3DCE framework to improve the location accuracy in lesion detection. Without the restriction of "anchors" on ratios and scales, anchors are decomposed to independent "anchor strings". Anchor segments are dynamically combined in accordance with probability, and anchor strings with different lengths dynamically compose bounding boxes. Experiments show that the accurate region proposals generated by our model promote the sensitivity of FPs and spend less inference time compared with the current methods.

A combined physical blending and surface grafting strategy for hydrophilic modification of polyethersulfone membrane toward oil/water separation

The block copolymer, Pluronic F127-block-poly(acrylic acid) (PAA-b-F127-b-PAA) was firstly synthesized via RAFT polymerization. Then, the copolymer was utilized as the blending modifier for fabricate polyethersulfone (PES)/PAA-b-F127-b-PAA composite membrane by nonsolvent induced phase separation technique. The hydrophilic PAA segments were concentrated onto the membrane surface due to the surface segregation phenomenon in the membrane formation process, which improved the hydrophilicity of the membrane surface and provided active sites for further surface grafting modification. Subsequently, the amine-terminated poly(sulfobetaine methacrylate) (NH2-PSBMA) was prepared through ARGET ATRP and used as surface modifier to fabricate PES/PAA-b-F127-b-PAA/PSBMA composite membrane by amination reaction. The composite membrane exhibited the highest pure water flux and oil flux around 358.25 and 217.53 L m−2 h−1, which equal to 5.6 times and 19.6 times of unmodified PES membrane respectively. The flux recovery rate increased from 45.74% to 94.64%, suggesting the fouling-resistance of the composite membranes was greatly improved. The hydrophobic PPO segments of PAA-b-F127-b-PAA used as anchor segments and amalgamated with PES molecular by hydrophobic interaction and physical intertwisting, resulting in the PAA-b-F127-b-PAA was firmly embedded in the membrane. Moreover, the PSBMA segments were grafted onto the membrane surface by forming strong chemical bonds, exhibiting excellent stability. It shows that this membrane material prepared by physical blending and surface grafting has a good application prospect in oil/water separation.

AFNet: Temporal Locality-Aware Network With Dual Structure for Accurate and Fast Action Detection

Inspired by Faster R-CNN, current state-of-the-art region-based action detection approaches like R-C3D and TAL-Net creatively proposed Temporal Region Proposal Network (TRPN) to generate proposals, which greatly improved action detection accuracy. However, since smooth L1 loss adopted in TRPN focuses on relative offset to pre-set anchor segments and is not sensitive enough to action boundaries and temporal regions, there is still room for improvement in temporal proposal generation. In this work, we elaborately design a Temporal Locality-Aware Network (TLAN) to learn a binary classifier using frame-level annotations. This allows our framework to effectively distinguish action instance (positive temporal regions) from background (negative temporal regions) by jointly optimizing temporal regions classification and temporal reference boxes regression, thus enabling precise localization. We further introduce a novel pooling method named Contextual Structured Spatial Temporal Pooling (CSSTP) to better exploit context and spatial-temporal information in an end-to-end fashion. Finally, TLAN and CSSTP are incorporated into a unified framework named AFNet. Extensive experiments have been conducted to evaluate the performance of our method. We achieve state-of-the-art performance on THUMOS’14 (20.6% higher than R-C3D, 6.7% higher than TAL-Net mAP @0.5) and competitive performance on Charades and ActivityNet. Besides, our inference speed reaches 1024 FPS, which is 250× faster than TAL-Net (3.5 FPS) and comparable to R-C3D (1030 FPS).

Proposal Complementary Action Detection

Temporal action detection not only requires correct classification but also needs to detect the start and end times of each action accurately. However, traditional approaches always employ sliding windows or actionness to predict the actions, and it is different to train to model with sliding windows or actionness by end-to-end means. In this article, we attempt a different idea to detect the actions end-to-end, which can calculate the probabilities of actions directly through one network as one part of the results. We present PCAD, a novel proposal complementary action detector to deal with video streams under continuous, untrimmed conditions. Our approach first uses a simple fully 3D convolutional network to encode the video streams and then generates candidate temporal proposals for activities by using anchor segments. To generate more precise proposals, we also design a boundary proposal network to offer some complementary information for the candidate proposals. Finally, we learn an efficient classifier to classify the generated proposals into different activities and refine their temporal boundaries at the same time. Our model can achieve end-to-end training by jointly optimizing classification loss and regression loss. When evaluating on the THUMOS’14 detection benchmark, PCAD achieves state-of-the-art performance in high-speed models.

Enhancement of the Photoalignment Stability of Block Copolymer Brushes by Anchor Segments

AbstractIt is known that the use of a homopolymer derived from a relatively high‐surface‐energy block moiety in a diblock copolymer as a substrate can facilitate phase separation of the block copolymer in the form of a layered structure parallel to the substrate. This is an effective approach for preparing a photoresponsive surface molecular brush for liquid‐crystal alignment. However, the alignment of the polymer brushes soon diminishes during elastic deformation of the polymeric substrate due to the weak interaction between the copolymer and polymeric substrate in the interfacial blend layer. In this study, rigid segments composed of N‐p‐anisylmaleimide were controllably introduced via copolymerization into a series of well‐defined diblock copolymers as “anchors” to resist the “drift” of the copolymer from a polymethyl methacrylate substrate at above its glass transition temperature. The anchoring mechanism and the stability of the aligned azobenzene polymeric brushes were systematically studied and compared.

Calculations of interfacial interactions in pyrene-Ipa rod sensitized nanostructured TiO2

Pyrene chromophores carrying different rigid rod spacer groups (ethynylene, ethynylene-phenylene-ethynylene, and ethynylene-bicyclo[2.2.2]octylene-ethynylene) and bound to TiO2 nanostructured materials via an isophthalic acid (Ipa) anchor group have been investigated using quantum chemical calculations in order to elucidate structural and electronic properties of dye-sensitized semiconductor structures capable of long-range photoinduced interfacial electron transfer. The calculations are used to study firstly the effect of the anchor and spacer groups on the electronic properties of the pyrene-dyes, secondly the binding of isophthalic acid to nanostructured TiO2, and thirdly the interfacial electronic interactions for dye-sensitized nanostructured TiO2 relevant to dye-sensitized solar cell applications. Together, these calculations provide theoretical insights into the effect of incorporating rigid rod anchor-cum-spacer group motifs in sensitizers for e.g. solar cell applications. In particular, the calculations help to rationalize the strong influence of the rods on the photophysical properties of the sensitizers in terms of electronic interactions between the individual chromophore, spacer, and anchor segments, as well as to provide information about interfacial electronic interactions of interest for the capabilities of the rods to act as efficient mediators of photoinduced interfacial charge separation.

Synthesis of novel amphiphilic copolymers by acid-mediated free-radical polymerization and solution as well as particle stabilization properties

Hydrophobically modified copolymers with different content of hydrophobic/hydrophilic segments can be synthesized by free radical copolymerization of acrylic acid (AA) with isobutene (IB) in the presence of strong Bronsted acids such as trifluoracetic acid (TFA). By variation of the comonomer ratio, the copolymer composition and its hydrophilic/hydrophobic properties can be adjusted. The copolymerization of AA and IB in the presence of TFA leads to copolymers which formally consist of periodic sequences of [IB-AA] X randomly interrupted by homo sequences of [AA] Y . This reflected from the linear dependence of the glass transition temperature with the [IB-AA] unit mole fraction while no direct correlation with the overall IB or AA mole fraction is given. The [IB-AA] sequences are relatively hydrophobic due to the IB unit, while [AA] sequences represent the hydrophilic part. Aqueous solutions of the periodic copolymers are characterized by specific and concentration dependent viscosities which are attributed to intermolecular association phenomena of alternating [IB-AA] X sequences. The copolymers have been shown to be potential stabilizers of titanium dioxide particle dispersions in water as has been established by electrokinetic sonic amplitude and sedimentation measurements. These data are again correlated with the periodic chain structure. A conformational model of [AA]y anchor segments as trains and [IB-AA] X loops and tails is proposed.

Characterization of the Secondary Structure and Membrane Interaction of the Putative Membrane Anchor Domains of Prostaglandin I2Synthase and Cytochrome P450 2C1

Prostaglandin I2synthase (PGIS) produces prostaglandin I2(PGI2) which has opposite actions on platelet aggregatory and vasoconstrictive properties compared to thromboxane A2(TXA2) produced from the same substrate by another P450 enzyme, thromboxane A2synthase (TXAS). PGIS and TXAS have only 16% amino acid sequence identity. Hydropathy analysis suggests that the putative NH2-terminal membrane anchor domain of PGIS is similar to many other membrane-bound microsomal P450s, which are believed to be anchored by a single transmembrane segment, and thus different from the TXAS anchor, which appears to have two transmembrane segments. To characterize the membrane anchor function of the PGIS NH2-terminal region, we have used the peptidoliposome reconstitution assay to identify the membrane anchor segment in the PGIS NH2-terminal domain and compared it with the anchor segment of P450 2C1. Four peptides, mimicking putative NH2-terminal membrane anchor segments of PGIS and P450 2C1, containing residues 1–28 (PGIS-LP1 and P450 2C1-LP1) or residues 25–54 (PGIS-LP2 and P450 2C1-LP2), were synthesized and their ability to insert in a lipid bilayer was evaluated. The results indicated that both LP1 peptides of PGIS and P450 2C1 became bound to the lipid bilayer, whereas both LP2 peptides did not bind the lipid. The two LP1 peptides were further characterized as to their conformation using CD spectroscopy. Helical structure induced in these peptides by addition of trifluoroethanol, dodecylphosphocholine, or incorporation into liposomes indicated that these segments tend to adopt a helical structure in a hydrophobic environment and thus could function as membrane anchor segments. These results support the hypothesis that PGIS and TXAS interact with the endoplasmic reticulum membrane in different ways, in which the NH2-terminal anchor domain of PGIS, as with P450 2C1, appears to have a single transmembrane segment.

Flexible membranes with anchored polymers

Compound systems are considered which consist of flexible membranes and polymers. The polymer chains are attached to the membrane surfaces via anchor segments. The non-anchored segments of the polymers, on the other hand, may be repelled from or attracted toward the membranes which leads to desorbed mushrooms or adsorbed pancakes, respectively. These anchored polymers change the local curvature of the membranes. In addition, they can act as adhesive stickers between membranes, a mechanism which underlies the adhesion of biomembranes.

Homology modelling and protein engineering strategy of subtilases, the family of subtilisin-like serine proteinases

Subtilases are members of the family of subtilisin-like serine proteases. Presently, greater than 50 subtilases are known, greater than 40 of which with their complete amino acid sequences. We have compared these sequences and the available three-dimensional structures (subtilisin BPN', subtilisin Carlsberg, thermitase and proteinase K). The mature enzymes contain up to 1775 residues, with N-terminal catalytic domains ranging from 268 to 511 residues, and signal and/or activation-peptides ranging from 27 to 280 residues. Several members contain C-terminal extensions, relative to the subtilisins, which display additional properties such as sequence repeats, processing sites and membrane anchor segments. Multiple sequence alignment of the N-terminal catalytic domains allows the definition of two main classes of subtilases. A structurally conserved framework of 191 core residues has been defined from a comparison of the four known three-dimensional structures. Eighteen of these core residues are highly conserved, nine of which are glycines. While the alpha-helix and beta-sheet secondary structure elements show considerable sequence homology, this is less so for peptide loops that connect the core secondary structure elements. These loops can vary in length by greater than 150 residues. While the core three-dimensional structure is conserved, insertions and deletions are preferentially confined to surface loops. From the known three-dimensional structures various predictions are made for the other subtilases concerning essential conserved residues, allowable amino acid substitutions, disulphide bonds, Ca(2+)-binding sites, substrate-binding site residues, ionic and aromatic interactions, proteolytically susceptible surface loops, etc. These predictions form a basis for protein engineering of members of the subtilase family, for which no three-dimensional structure is known.

Lipid‐Coated Particles–A New Approach to Fix Membrane‐Bound Enzymes onto Carrier Surfaces

A new method to covalently link phosphatidylethanolamine via the headgroup at the surface of cell-size spherical polymer particles is described. Because the density of the reactive groups linked to the polymer beads is extremely high, a dense, tightly bonded lipid monolayer is formed. When a solubilized lipid is added to the suspension of monolayer-coated polymer beads, the spontaneous formation of a bilayer-like structure is observed. The upper layer of lipid can be removed by washing with detergent solution or organic solvents, ethanol or butanol, and can be replaced in a relipidation step by any other phospholipid; thus, an asymmetric lipid bilayer structure can be formed. Membrane-bound enzymes such as alanine aminopeptidase or dipeptidyl peptidase IV may be inserted with their hydrophobic anchor segments in a stable and enzymatically active form in this artificial system. Incorporation of integral membrane enzymes such as bacteriorhodopsin with membrane-spanning domains and bulky segments at both sides of the membrane succeeded only when a hydrophilic spacer of appropriate length (e.g., pentaalanine) was introduced between the carrier surface and the lipid headgroups.

Control of glycoprotein synthesis. Purification of UDP-N-acetylglucosamine:alpha-D-mannoside beta 1-2 N-acetylglucosaminyltransferase II from rat liver.

A new affinity chromatography adsorbant, in which UDP-GlcNAc has been linked to thiopropyl-Sepharose at the 5 position of the uracil via a 5-mercuri mercaptide bond, was utilized to purify UDP-GlcNAc:alpha-D-mannoside beta 1-2 N-acetylglucosaminyltransferase II 60,000-fold from rat liver. After extraction of rat liver membranes with Triton X-100, the enzyme was found to exist in two molecular weight forms of markedly differing size, separable on Sephadex G-200. The low Mr form was separated from the high Mr form on columns of CM-Sephadex and hydroxylapatite, and was further purified by sequential elutions with NaCl, UDP-GlcNAc, and EDTA from the 5-mercuri-UDP-GlcNAc affinity adsorbant. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified low Mr form under reducing conditions revealed two protein bands of Mr 48,000 and 43,000. The purified enzyme catalyzes the transfer of N-acetylglucosamine from UDP-GlcNAc to the compound: (Formula: see text) The high Mr form of the enzyme, which eluted in the void volume of Sephadex G-200, was resistant to a number of treatments in attempts to reduce its molecular weight. These results suggest that the high Mr form of the enzyme may represent either a complex which normally exists in Golgi membranes as a result of strong protein-protein interactions or a protein with one or more "anchor" segments.

America's Other Youth: Growing up Poor.

Getting Started. Platform. Naming Conventions. Key Commands. The CD-ROM and Initial Setup Considerations. Introduction. Digital Graphic Images. Step by Step. 1. FreeHand Workflow. The FreeHand Environment. The Pointer Tool. Creating, Opening, and Saving a Document. Document Inspector. FreeHand Defaults. The Status Bar. Wizards. FreeHand Help. 2. The FreeHand Working Environment. The Toolbars. Flexibility of Toolbars. Panels. Inspectors. FreeHand Menus. Viewing Modes. The Magnify Tool. New Window. 3. Rulers, Grids, and Guides. The Page Rulers. Guides. Grids. Perspective Grid. 4. Drawing Basics. Basic Shapes Drawing Tools. Composition of Your Artwork. The Pointer Tool and Object Inspector. Pointer Tool. Object Inspector. Moving Objects with the Pointer Tool. The Drawing Tools. 5. Painting FreeHand Objects. Understanding Color. The Color Models. The Color Mixer. Fills and Strokes. Fill Inspector. Stroke Inspector. 6. Anchor Points, Paths, and Segments. Selecting a Single Anchor Point. Adding Points to a Path. Deleting Anchor Points. Moving Segments of a Path. Connecting Anchor Points. Curve Basics. The Knife Tool. The Freeform Tool. 7. Arranging, Aligning, and Distributing Objects. Arranging Objects. Locking and Unlocking Objects. Grouping and Ungrouping Objects. Aligning and Distributing Objects. Align to Page. Layers. The Layers Options. Managing Layers. Layer Priority. Settings for Work Efficiency. 8. Advanced Drawing. Using Lens Fills. Envelopes. Working with Perspective. Converting Images by Tracing. Symbols and Instances. Project Assignment #1. Review #1. 9. Creating and Editing Text. Assigning Text Attributes. Text Character Settings. Text Paragraph Settings. Text Spacing Settings. Text Columns & Rows Settings. Adjust Columns Settings. Using Text Styles. The Menu's Unique Features. Working with Tabs. Linking Text Blocks. Special Effects with Text and Paths. Creating Paths from Text. 10. FreeHand as a Layout Tool. Document Preparation. Managing Guides. Creating Longer Documents. 11. Transformation Tools. Transformation Modes. Using the Interactive Transformer. Duplicating, Cloning, and Step and Repeat. 12. Path Operations. Operations that Combine Objects. Path-altering Operations. 13. Xtras. The Xtras. Xtras Manager. Xtra Tools. 14. Importing and Exporting. Getting Information into FreeHand. Vector Images. Raster (bitmap) Images. Linking and Embedding Imported Graphics. Exporting. 15. Printing and Separating. Getting Color on Paper: The Basics. Page Description Languages. Screening. The Setup Dialog Options. Print Setting. Using PPD. Preview area. Overprinting Black. Imaging. Tiling. 16. Graphics for the Web. Web Publishing vs. Print. Creating Flash Graphics. Project Assignment #2. Review #2. Projects. Project A: Dinner Time. Project B: Mask Art. Project C: Tropical Treasure Logo. Project D: Grocery Ad. Project E: Ball and Mirror. Project F: No Clowning Around. Glossary (Supplied on CD-ROM in PDF Format). Index.