Pair Of Blocks Research Articles

Janus Blocks: A Binary System Wear Instability

In this manuscript, a simple binary model is devised that describes the wear behavior of two blocks coupled under a constant, dynamically partitioned normal load. In this simple system, the frictional force is reacted by two independent springs and the blocks are allowed to move and wear independently based on system dynamics and kinematics. The only coupling between the blocks occurs through the partitioning of the applied normal load, which uses a pair of springs in parallel to model elasticity. This system is found to preferentially wear one of the blocks until two disparately unique conditions of steady wear are reached in the system: (1) a condition in which the partitioning of the load between the blocks yields equal wear and thus steady partitioning of the load and (2) a condition in which the pair of blocks go to zero wear by having one block not sliding but carrying all of the load and the other block completely slipping but carrying none of the load. These “Janus blocks,” the simplest of binary spring–block systems, begin life in a nominally identical state and then their behavior bifurcates, producing runaway or irregular wear. The onset of this instability can initiate from any differences in load partitioning, spring constants, friction coefficient, or wear rates (no matter how small).

Evolution of the defensin-like gene family in grass genomes.

Plant defensins are small, diverse, cysteine-rich peptides, belonging to a group of pathogenesis-related defense mechanism proteins, which can provide a barrier against a broad range of pathogens. In this study, 51 defensin-like (DEFL) genes in Gramineae, including brachypodium, rice, maize and sorghum were identified based on bioinformatics methods. Using the synteny analysis method, we found that 21 DEFL genes formed 30 pairs of duplicated blocks that have undergone large-scale duplication events, mostly occurring between species. In particular, some chromosomal regions are highly conserved in the four grasses. Using mean Ks values, we estimated the approximate time of divergence for each pair of duplicated regions and found that these regions generally diverged more than 40 million years ago (Mya). Selection pressure analysis showed that the DEFL gene family is subjected to purifying selection. However, sliding window analysis detected partial reg ions of duplicated genes under positive selection. The evolutionary patterns within DEFL gene families among grasses can be used to explore the subsequent functional divergence of duplicated genes and to further analyse the antimicrobial effects of defensins during plant development.

Abstract S6-02: Occurrence of natural ESR1 mutations during acquisition of endocrine resistance in breast cancers and widely used ER+ cell lines

Abstract Background: There is great interest in the mutational landscape of metastatic breast cancer (BC) for personalised medicine. Knowledge about how this landscape differs in recurrent lesions from primary BC as a result of metastatic selection or the impact of treatment will extend our knowledge of mechanisms of endocrine resistance and determine the manner in which diagnostics and treatment are integrated. A small number of limited series have reported an increased presence of ESR1 mutations in metastatic lesions after endocrine treatments including aromatase inhibitors (AIs) which are the most common agents for ER+ postmenopausal BC. Aim: To determine the change in mutational profile of 16 genes affected by driver mutations in patients with metastatic BC at the time of progression after an AI. Methods: We conducted targeted sequencing with a custom AmpliSeq panel in 48 matched pairs of FFPE archival blocks of pre-treatment diagnostic and recurrent lesions. 24 of these were metastatic, 24 local recurrences. The genes were AKT1, BRAF, CDH1, ERBB2, ESR1, GATA3, KIT, KRAS, MAP2K4, MAP3K1, PIC3CA, PIK3R1, PTEN, RUNX, SF3B1 and TP53. Only mutations with high depth (>250x) were retained. Germline mutations were identified by 1000 Genomes Project data. C:G>T:A transitions with low frequency (<10%) were removed as artefacts from formalin cross-linking. Results: Median coverage was 782-fold. Good quality data was available on 42 pairs. At least one mutation was found in 34 pairs. Three cases had lost IHC expression of ER in the recurrence. A total of 115 mutations in coding regions or splice sites were identified, the largest number in PIK3CA (in 20 samples), CHD1 (18), MAP3K1 (12), TP53 (12) and PTEN (9). In 47 instances the mutation was private to one or other sample. There was no difference in the number of mutations between the presentation and recurrent lesions. Six ESR1 mutations were found, all private to 5 recurrent lesions (all IHC ER+). Four of these mutations have been previously reported (2x E380Q, 2x D538G), one was novel (D484G) and also in the ligand-binding domain. One had an additional previously reported mutation (H524L). Four of these lesions were metastatic but one in a local recurrence suggesting that the metastatic process is more likely, but not essential in selecting the emergence of ESR1 mutations. HER2 mutations were identified in 3 patients; in two cases private in the presentation tumour while in the other case the mutation in the recurrent lesion (L755S) differed from that in the primary. L755S has been reported to be sensitive to neratinib in experimental systems. CDH1 (e-cadherin) mutations were numerically higher than reported in other series. The mutations were across the gene and private in 4 pretreatment and 2 recurrent lesions (6 had identical mutations). They were not associated with lobular phenotype. Conclusions: These data confirm that recurrences after AI but not primary ER+ tumours often contain ESR1 mutations that could influence clinical decision making. The high number of CDH1 mutations at diagnosis may be at least in part because of the selection of recurrent ER+ cases. The data stress the individuality of mutational profiles in recurrent BC and the need for individual interpretation of the data. Citation Format: Gellert P, Ribas R, Pancholi S, Lopez-Knowles E, Yeo B, Garcia-Murillas I, Pearson A, Smith I, Turner N, Dowsett M, Martin L-A. Occurrence of natural ESR1 mutations during acquisition of endocrine resistance in breast cancers and widely used ER+ cell lines. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S6-02.

Measurement of Refractive Index of Liquids Using Length Standards Traceable to SI Unit

Many workers have published various methods to measure refractive index of various liquids. Mostly, the measurement results are not traceable to SI units. A novel method is developed at CSIR-NPL, India (NPLI) to measure refractive of index of liquids using gauge blocks, metrological microscope and displacement laser interferometer. A vessel with flat bottom is chosen to hold the liquid under test. A pair of gauge blocks of different lengths is fixed in the vessel. The vessel is arranged under a vertically movable microscope. A calibrated displacement laser interferometer is attached to the microscope stage. The microscope is focused to the surface of gauge block before poring liquid. After poring liquid in the vessel, the microscope is moved vertically to regain the focussed image of surface of submerged gauge blocks. The measurement method is simulated mathematically. The refractive index of liquid medium is calculated using this mathematical model. Refractive index of water, isopropyl alcohol is measured. Various error contributing sources are identified. The measurement uncertainty is evaluated.

Using Fractal Dimension and Singular Values for Image Forgery Detection and Localization

Verification of the authenticity of images that are circulated through media and public outlets is a critical issue in image forensics. Copy-move forgery is the most common image forgery that conceals a particular feature from the scene by replacing it with another feature of the same image. We propose a hybrid approach based on local fractal dimension (LFD) and singular value decomposition (SVD) to efficiently detect and localize the duplicated regionsin images. First the image is partitioned into fixed size blocks and the local fractal dimension is estimated. In order to reduce the inherent computational complexity of fractal techniques, the image blocks are arranged in a B+ tree based on the LFD values. Pair of blocks within each segment is compared using singular values, to find regions that exhibit maximum resemblance. This reduces the need for comparison to the most suspected image portions alone. The experimental results show how effectively the method identifies the duplicated region; also presents the robustness of the method to detect forgery in the presence of after-copying manipulations such as rotation, blurring of edges and noise addition. The method proves to be effective in detecting multiple forgeries within the image.

Layer-by-layer assembly of versatile nanoarchitectures with diverse dimensionality: a new perspective for rational construction of multilayer assemblies.

Over the past few decades, layer-by-layer (LbL) assembly of multilayer thin films has garnered considerable interest on account of its ability to modulate nanometer control over film thickness and its extensive choice of usable materials for coating planar and particulate substrates, thus allowing for the fabrication of responsive and functional thin films for their potential applications in a myriad of fields. Herein, we provide elaborate information on the current developments of LbL assembly techniques including different properties, molecular interactions, and assembly methods associated with this promising bottom-up strategy. In particular, we highlight the principle for rational design and fabrication of a large variety of multilayer thin film systems including multi-dimensional capsules or spatially hierarchical nanostructures based on the LbL assembly technique. Moreover, we discuss how to judiciously choose the building block pairs when exerting the LbL assembly buildup which enables the engineering of multilayer thin films with tailor-made physicochemical properties. Furthermore, versatile applications of the diverse LbL-assembled nanomaterials are itemized and elucidated in light of specific technological fields. Finally, we provide a brief perspective and potential future challenges of the LbL assembly technology. It is anticipated that our current review could provide a wealth of guided information on the LbL assembly technique and furnish firm grounds for rational design of LbL assembled multilayer assemblies toward tangible applications.

Теоретичні основи нового підходу до розв’язання задачі виявлення результатів клонування у цифровому зображенні, що збережено у форматі з утратами

It was proposed the theoretical basis for a new solution to the problem of identifying the cloning results for a digital image saved after a change in the lossy format. The approach is based on the account of the smallness changes in the volume of the cylindrical body bounded above graph interpolation function for image matrix from below by XOY-plane under the compression process. An indication of the presence of cloning area or pre-image of the clone is the proximity of the values of double integrals of the interpolation function on appropriate areas domain of the function that defines the original image. The characteristic differences between the sums of matrix elements for the absolute difference of pairs of non-overlapping blocks of the image matrix, which allow localize area of the clone and its prototype. The identified differences occur regardless of the features and characteristics of the image of the pre-image (clone); their subsequent quantitative evaluation is going to provide an opportunity to develop a method to solve the assigned task. Fig.: 5. Refs: 9 titles.

Learning-based superresolution algorithm using quantized pattern and bimodal postprocessing for text images

This paper proposes a learning-based superresolution algorithm using text characteristics for text images. The proposed algorithm consists of a learning stage and an inference stage. In the learning stage, a sufficient number of low-resolution (LR) to high-resolution (HR) block pairs are first extracted from various LR–HR image pairs that are composed of texts. Then, we classify those block pairs into 512 clusters and, for each cluster, calculate the optimal two-dimensional (2-D) finite impulse response (FIR) filter to synthesize a high-quality HR block from an LR block and store the block-adaptive 2-D FIR filters in a dictionary with their associated index. In the inference stage, we find the best-matched candidate to each input LR block from the dictionary and synthesize the HR block using the optimal 2-D FIR filter. Finally, an HR image is produced via proper postprocessing. Experimental results show that the proposed algorithm provides superior visual quality to images from previous works and outperforms previous processes in terms of computational complexity.

Detection of Duplicate Region and Hybrid Non-Local Means Filtering for Denoising with Quantization Matrix Estimation for JPEG Error Analysis

Background: The existing JPEG error analysis schemes do not offer agreeable results particularly when the duplicated area is small. Region duplication is an uncomplicated and efficient process to produce digital image forgeries, where a constant segment of pixels in an image, following feasible geometrical and illumination transformations are copied and pasted to a different location in the same image. Methods: In this research work, JPEG error analysis scheme is introduced for the purpose of consistent recognition of duplicated and distorted areas in a JPEG digital image forensics. Here, presented a new Multi-directional Curvelet Transform with Fourier Transform matching Invariant Rotation (MCFTIR) region duplication detection scheme to identify duplicated regions for JPEG images. This scheme begins with estimating the overlapping blocks of a JPEG image and it is organized in accordance with the statistics of multiple curvelet sub-bands. During the second phase, the amount of candidate block pairs of JPEG images has been significantly diminished by means of spatial distance between each pair of blocks for JPEG image. For duplicate region removed images theoretically analyzing the effects of these errors on single and double JPEG compression, with five major phases like Shape-Preserving Image Resizing (SPIR) scheme for the purpose of image resizing, noises are appended to image and eliminated with the help of Hybrid Non-Local Means Filtering (HNLMF) denoising framework, Image compression through Discrete Cosine Transform – Singular Value Decomposition (DCT-SVD) was computed for single and double image compression, images were quantized by means of numerous quantization matrices, quantization matrix results are estimated with Mamdani model based Adaptive Neural Fuzzy Inference System (MANFIS) and detecting the quantization table of a JPEG image. Findings: The proposed MCFTIR methods significantly outperform existing techniques in terms of the parameters like Peak Signal to Noise Ratio (PSNR) and Mean Square Error (MSE) especially for the images of small sizes. It also show that the new MCFTIR method can consistently identify JPEG image blocks which are as tiny as 8x8 pixels and compressed through quality factors as elevated as 98. This performance is significant for the purpose of analyzing and locating small tampered regions inside a composite image.

Exploiting a novel miR-519c–HuR–ABCG2 regulatory pathway to overcome chemoresistance in colorectal cancer

Colorectal cancer (CRC) is a major cause of mortality and morbidity worldwide. While surgery remains the mainstay of treatment for early stage CRC, adjuvant chemotherapy is usually given to reduce the risk of recurrence after colectomy. Overexpression of a multidrug resistance (MDR) transporter ABCG2 in vitro has been shown to cause resistance to 5-fluorouracil (5-FU) and irinotecan, components of the most commonly adopted regimens for treating CRC. Both anticancer drugs are known ABCG2 substrates. An effective way to predict drug response may provide guidance for better cancer treatment. We investigated the effect of ABCG2 dysregulation on cancer cell sensitivity to chemotherapy using pairs of snap-frozen paraffin-embedded archival blocks of human colorectal cancer tissues and their matched non-cancerous colon tissues from CRC patients. In CRC patients responding to chemotherapy, the tumors were found to have remarkable lower ABCG2 expression than the adjacent normal colon tissues. On the contrary, the tumors from patients not responding to 5-FU-based chemotherapy have higher ABCG2 level than the adjacent normal tissues. The high ABCG2 expression in the tumor is associated with the concomitant overexpression of the mRNA binding protein HuR but a low expression of miR-519c because miR-519c is known to target both ABCG2 and HuR. Further investigation in CRC cell lines revealed that the ABCG2 overexpression was caused by an interplay between miR-519c, HuR and the length of the 3′ untranslated region (UTR) of ABCG2. These parameters may be further developed as useful biomarkers to predict patient response to adjuvant chemotherapy. Besides being predictive biomarkers, the microRNAs and mRNA binding protein identified may also be potential drug targets for modulating ABCG2 to combat resistance in CRC chemotherapy.

Automated gauge block pair length difference calibration and associated uncertainty sources

A reduction for interferometric uncertainties in length difference at gauge block pairs is presented. An automated processing designed to compensate geometric fringe visualization effects and four-alternate wringing technique are used to achieve small combined uncertainties for length difference calibrations, maintaining a good compliance with the EAL-G21 determinations.

Induction of Secondary Structure through Micellization of an Oppositely Charged Pair of Homochiral Block- and Homopolypeptides in an Aqueous Medium.

Polyion complex (PIC) formation is an attractive method for obtaining molecular assemblies owing to their facile fabrication process in aqueous media, but more insights are required in order to control the higher-dimensional structures of polypeptide-based PICs. Herein, the PIC formation behavior of oppositely charged homochiral polypeptides, poly-L-lysine and poly(ethylene glycol)-b-poly(L-glutamate) (PEG-PLG), and their secondary structures are carefully studied in water. PIC formation takes place in a polymer concentration-dependent manner, and clear β-sheet formation is observed at polymer concentrations ≥0.3 mg mL(-1). The results also confirm that multimolecular aggregation is a prerequisite for β-sheet formation, which indicates that the inner hydrophobic environment of PICs is favorable for β-sheet formation. Furthermore, the PEG weight fraction, stereoregularity of the polypeptide, and ionic strength of the solutions are found to be key factors for generating a secondary structure, presumably because these factors can contribute to the tuning of the inner environment of PICs. This method of producing water-soluble nanoassemblies from oppositely charged polypeptides may expedite self-assembly studies in biological systems and be incorporated into various molecular systems to exploit protein-mimicking features.

Copy-move image forgery detection based on Gabor magnitude

With advancement of media editing software, even people who are not image processing experts can easily alter digital images. Various methods of digital image forgery exist, such as image splicing, copy-move forgery, and image retouching. The most common method of tampering with a digital image is copy-move forgery, in which a part of an image is duplicated and used to substitute another part of the same image at a different location. In this paper, we present an efficient and robust method to detect such artifacts. First, the tampered image is segmented into overlapping fixed-size blocks, and the Gabor filter is applied to each block. Thus, the image of Gabor magnitude represents each block. Secondly, statistical features are extracted from the histogram of orientated Gabor magnitude (HOGM) of overlapping blocks, and reduced features are generated for similarity measurement. Finally, feature vectors are sorted lexicographically, and duplicated image blocks are identified by finding similarity block pairs after suitable post-processing. To enhance the algorithm’s robustness, a few parameters are proposed for removing the wrong similar blocks. Experiment results demonstrate the ability of the proposed method to detect multiple examples of copy-move forgery and precisely locate the duplicated regions, even when dealing with images distorted by slight rotation and scaling, JPEG compression, blurring, and brightness adjustment.

Detection of contacts between three-dimensional polyhedral blocks for discontinuous deformation analysis

A new algorithm to detect contacts between three-dimensional (3-D) arbitrarily shaped polyhedral blocks for the discontinuous deformation analysis (DDA) method is presented in this paper. The new algorithm includes three main steps, i.e. neighbor search, contact type examination, and entrance candidate identification, all of which are performed using the general features and relations of geometric elements of polyhedra. First, contact detection begins with searching neighbor blocks and vertices potential to be in contact in order to improve the computation efficiency. Then, pairs of neighbor blocks are examined in more detail for four basic contact types. Finally, corresponding contact points and planes for each contact type are identified by general entrance formulas, which is prepared for the subsequent contact force calculations in the program. The new algorithm has been implemented in the original 3-D DDA program and the extended 3-D DDA program can display the results using OpenGL. Three typical contact examples including concave blocks, i.e. vertex-to-concave-edge, convex-edge-to-concave-edge and vertex-to-concave-vertex contacts are provided to verify the new algorithm. Additionally, a practical example in rock engineering, sliding of a tetrahedral wedge, is also presented, and the 3-DDA results are compared with the analytical solutions.

글자 영상을 위한 학습기반 초고해상도 기법

The proposed algorithm consists of two stages: the learning and synthesis stages. At the learning stage, we first collect various high-resolution (HR)-low-resolution (LR) text image pairs, and quantize the LR images, and extract HR-LR block pairs. Based on quantized LR blocks, the LR-HR block pairs are clustered into a pre-determined number of classes. For each class, an optimal 2D-FIR filter is computed, and it is stored into a dictionary with the corresponding LR block for indexing. At the synthesis stage, each quantized LR block in an input LR image is compared with every LR block in the dictionary, and the FIR filter of the best-matched LR block is selected. Finally, a HR block is synthesized with the chosen filter, and a final HR image is produced. Also, in order to cope with noisy environment, we generate multiple dictionaries according to noise level at the learning stage. So, the dictionary corresponding to the noise level of the input image is chosen, and a final HR image is produced using the selected dictionary. Experimental results show that the proposed algorithm outperforms the previous works for noisy images as well as noise-free images.

Knowing Your Limits: How a Time Constraint May Impact Spatial Reasoning

We set out to evaluate how spatial ability (SA) relates to temporal and spatial patterns in average fixation duration (AFD). We hypothesized that SA would be negatively correlated with AFD. Additionally, we asserted that SA would be positively related to AFD in the spatially salient regions of interest (ROIs) of structures presented on a spatial test. The SA test was timed and based on the line drawings of Shepherd and Metzler. Individuals chose whether block pairs were rotations (same), or mirrored (different) images. Eye tracking revealed a significant relationship between AFD and SA (r = ‐.92*, n=10, p<.0001). This suggests that high SA individuals are able to discern and attend to the spatially salient features required to interpret spatial structures more rapidly than low scorers. Through the creation of spatial ROIs, the relationship between SA and AFD in different areas of the images (Bend, Tail, Straight or Empty) was revealed. When the proportional AFD was related to SA, two relationships were found; a negative relationship between the Tail AFD and SA (r=‐.65*, n=10, p=.042), and a positive relationship between the Straight AFD and SA (r=.66*, n=10, p=.037). Thus, low SA individuals dwell on the tail regions, using tail position to solve the question, while the high SA individuals quickly observe the tails, and store the information in their working memory for reference, as they proceed through the test.

Patterns of modulation in the activity and connectivity of motor cortex during the repeated generation of movement sequences.

It is not clear how the engagement of motor mnemonic processes is expressed in online brain activity. We scanned participants, using fMRI, during the paced performance of a finger-to-thumb opposition sequence (FOS), intensively trained a day earlier (T-FOS), and a similarly constructed, but novel, untrained FOS (U-FOS). Both movement sequences were performed in pairs of blocks separated by a brief rest interval (30 sec). We have recently shown that in the primary motor cortex (M1) motor memory was not expressed in the average signal intensity but rather in the across-block signal modulations, that is, when comparing the first to the second performance block across the brief rest interval. Here, using an M1 seed, we show that for the T-FOS, the M1-striatum functional connectivity decreased across blocks; however, for the U-FOS, connectivity within the M1 and between M1 and striatum increased. In addition, in M1, the pattern of within-block signal change, but not signal variability per se, reliably differentiated the two sequences. Only for the U-FOS and only within the first blocks in each pair, the signal significantly decreased. No such modulation was found within the second corresponding blocks following the brief rest interval in either FOS. We propose that a network including M1 and striatum underlies online motor working memory. This network may promote a transient integrated representation of a new movement sequence and readily retrieves a previously established movement sequence representation. Averaging over single events or blocks may not capture the dynamics of motor representations that occur over multiple timescales.

An efficient forgery detection algorithm for object removal by exemplar-based image inpainting

As a popular image manipulation technique, object removal can be achieved by image-inpainting without any noticeable traces, which poses huge challenges to passive image forensics. The existing detection approach utilizes full search for block matching, resulting in high computational complexity. This paper presents an efficient forgery detection algorithm for object removal by exemplar-based inpainting, which integrates central pixel mapping (CPM), greatest zero-connectivity component labeling (GZCL) and fragment splicing detection (FSD). CPM speeds up suspicious block search by efficiently matching those blocks with similar hash values and then finding the suspicious pairs. To improve the detection precision, GZCL is used to mark the tampered pixels in suspected block pairs. FSD is adopted to distinguish and locate tampered regions from its best-match regions. Experimental results show that the proposed algorithm can reduce up to 90% of the processing time and maintain a detection precision above 85% under different kinds of object-removed images.

Detection of copy–move image forgery using histogram of orientated gradients

The increasing popularity of digital media and media editing software has led to widespread tampering of multimedia files for malicious purposes. The most common form of tampering associated with digital images is copy–move forgery, in which a portion of an image is duplicated and substituted in a different location. Thus, law enforcement and forensics experts require reliable and efficient means of detecting copy–move forgery. This paper proposes a blind forensics approach to the detection of copy–move forgery. The input image is segmented into overlapping blocks, whereupon a histogram of orientated gradients is applied to each block. Statistical features are extracted and reduced to facilitate the measurement of similarity. Finally, feature vectors are lexicographically sorted, and duplicated image blocks are detected by identifying similar block pairs after post-processing. Experiment results demonstrate that the proposed method is able to detect multiple examples of copy–move forgery and precisely locate the duplicated regions, even when dealing with images distorted by translation involving small rotations, blurring, adjustment of brightness, and color reduction. We are currently working to improve detection in regions with rotation and scaling adjustment over large areas.

Some modifications to the process of discontinuous deformation analysis

This paper presents a modified method of discontinuous deformation analysis (DDA). In the presented method, open-close iteration may not be needed, small penetration is permitted among blocks, and springs are added between contacting block pairs only when a penetration takes place. The three contact patterns (i.e. sliding, locking and opening) in original DDA method are not involved, and the recognition of these contact patterns and treatment of transformation among patterns are not required either, significantly saving the computing time. In a convex to concave contact, there are two candidate entrance edges which may cause uncertainty. In this case, we propose the angle bisector criterion to determine the entrance edge. The spring stiffness is much larger than Young's modulus in the original DDA, however we find that the correct results can still be obtained when it is much smaller than Young's modulus. Finally, the penetrations by using penalty method and augmented Lagrangian method are compared. Penetration of the latter is 1/4 of the former. The range of spring stiffness for the latter is wider than the former, being 0.01–1 of the former. Both methods can lead to correct contact forces.