Reverse Mapping Research Articles

Castles in the Clouds: LiDAR for Historical Study and Terrain Analysis

Examples of castles and fortresses seen in publicly available LiDAR data by the national mapping agencies in Finland, the Netherlands, Norway, Slovenia, the United Kingdom, and United States demonstrate the value of LiDAR data for understanding military history. The data sets, which include derived grids and the original point clouds with densities from 2–24 points/m², always identify the ground points, generally include LiDAR return intensity values, and sometimes include point classifications that discriminate vegetation and buildings. Grids with 0,5- or one-metre resolution could be created from the highest density point clouds in this study, while grids with one- or two-metre resolution can be created from the lowest density clouds. The digital surface model, which includes everything seen by the sensor, notably ground, buildings, and vegetation, can be created with higher resolution than the bare earth grids. The surface model provides the best visual representation of the castle and its surroundings. Viewed in interactive 3D, the data allows familiarisation with the landscape. Optimal displays depend on the desired scale and the terrain characteristics, but hillshade or shaded reflectance maps, reverse greyscale slope maps, and openness maps all work effectively. Further analysis may include functions such as viewsheds, which enhance the understanding of key terrain.

Product infant failure risk modeling based on quality variation propagation and functional failure dependency

Product infant failure is the most crucial part of product quality risk that critically affects customer satisfaction. However, most of manufacturers lack sufficient understanding of the formation mechanism of product infant failure and quantitative infant failure risk modeling technology. These issues cause the inefficiency of warranty policy in preventing and controlling infant failure risk. Therefore, first, on the basis of the reverse mapping process of axiomatic design, an infant failure risk formation chain, that is, “process quality variation—physical defect—functional vulnerability—infant failure,” is proposed in this study by considering quality variation propagation and functional failure dependency to determine the inherent formation and dependent enlarging process of the risk. Second, on the basis of the risk formation chain, the infant failure risk is modeled from inherent risk and dependent risk. Specifically, the inherent infant failure risk is computed based on the stream of quality variation in production, whereas the dependent infant failure risk is computed by a Bayesian network by considering the functional failure dependency. Finally, a case study of an illustrative electromechanical system is introduced to verify the applicability of the proposed method. Result shows that the proposed method has a better performance in infant failure risk modeling.

Location of arm draining lymph node in relation to breast cancer radiotherapy field and target volume

BackgroundLymphoedema of the arm following axillary surgery or radiotherapy remains a significant side effect affecting some women after breast cancer treatment. Axillary reverse mapping (ARM) is a technique used to identify the lymph node draining the arm (ARM node). Our study aim was to examine the location of the ARM nodes in relation to target volumes and treatment fields for breast cancer radiotherapy. Materials and methodsEighteen breast cancer patients underwent lymphoscintigraphy of contralateral arm (left 10, right 8) and SPECT CT scan on a research study. Patient position for the SPECT CT scan approximated the position used for radiotherapy. Using MIM software™, the ARM node for each subject was contoured on the SPECT CT and verified by a nuclear medicine physician. The CT component of the SPECT CT was then transferred to ECLIPSE™ radiotherapy planning software, and the contralateral breast and axilla were contoured on this CT scan according to the ESTRO contouring guideline. Two radiotherapy plans were generated for each subject using standard tangential IMRT technique at a dose of 50 Gy in 25 fractions, one treating contralateral breast alone, the other treating contralateral breast and contralateral axilla level 1–4. The ARM node was considered “within the radiotherapy field” if the mean dose received by the ARM node was more than 50% of the prescribed dose: i.e., 25 Gy. ResultsOne right-sided subject had 2 ARM nodes, all others had 1 ARM node. All ARM nodes (left 10, right 9) were located within level 1 of the axilla. For the subject with 2 ARM nodes, the node that received a higher dose was used for the analysis. The mean dose received by the ARM node in the whole breast radiotherapy plans ranged from 0.8 to 45.5 Gy, with a median of 10.9 Gy. The mean dose received by the ARM node in the whole breast and axilla plans ranged from 43.4 to 52.5 Gy, with a median of 49.3 Gy. In the whole breast radiotherapy plans, only 5 out of 18 ARM nodes were found to be “within radiotherapy field”, and only 2 ARM nodes received more than 40 Gy. In the breast and axilla plans, all 18 ARM nodes were “within radiotherapy field” and all received more than 40 Gy. To better visualise the locations of ARM nodes, all left sided ARM nodes were then mapped onto a CT set from one of the left-sided subjects, and all the right sided ARM nodes mapped onto one of the right-sided subjects, and digitally reconstructed radiograph (DRR) for radiotherapy fields were produced. ConclusionsOur study demonstrates that the vast majority of ARM nodes (72%) are outside the tangential whole breast radiotherapy fields. In our study, all the ARM nodes were within the axillary radiotherapy fields covering level 1–4 axillary volumes according to the ESTRO contouring guideline, and complete shielding of the humeral head according to the EORTC consensus did not lead to sparing of the ARM nodes. A prospective study is needed to examine the oncological safety of ARM node-sparing axillary radiotherapy and its potential to reduce the risk of arm lymphoedema.

Donor limb assessment after vascularized groin lymph node transfer for the treatment of breast cancer-related lymphedema: Clinical and lymphoscintigraphy findings

Vascularized lymph node transfer is an established treatment for secondary lymphedema. Different donor sites of lymph node flap have been described. In our institute, vascularized groin lymph node (VGLN) flap is the workhorse flap for treating breast cancer-related lymphedema (BCRL). Potential complications of VGLN flap harvesting include seroma formation, thigh dysaesthesia, and iatrogenic lymphedema. Between August 2013 and June 2016, 30 consecutive patients with a mean age of 60 years underwent VGLN transfer for BCRL. Reverse mapping of lower limb lymphatics with patent blue solution was performed in all cases. The donor limb conditions were assessed clinically with limb circumference measurement and radiologically with lymphoscintigraphy. Postoperative lymphoscintigraphy findings and transport indexes were compared between the donor and nonoperated limbs. The mean follow-up period was 22.11 ± 7.83 months. Three (10%) patients developed groin seroma and 18 (60%) patients complained of transient thigh dysaesthesia. There was no clinically detectable donor limb lymphedema. Lymphoscintigraphy was performed at a mean of 13 months after operation. The mean transport indexes of the nonoperated limbs and donor limbs were 2.04 and 3.32, respectively. For the donor limbs, all patients had normal distribution pattern of contrast uptake. No dermal backflow pattern was demonstrated. With good knowledge of groin anatomy and meticulous surgical skills, VGLN flap can be harvested without causing major consequence to the donor limb.

New Back-filtering PFA Imaging Algorithm and Distortion Correction Method for Missile-borne Bistatic SAR with Curved Track

The traditional bistatic equivalent range model has low accuracy and make the traditional Polar Format Algorithm (PFA) are inapplicable in missile-borne bistatic Synthetic Aperture Radar (SAR) imaging with curved track due to the existing of three-axis velocity and acceleration. In addition, due to the existing of space-variant motion error introduced by acceleration, the traditional 2-D sub-block compensation method will cause the discontinuities between the image sub-blocks, thus affecting the subsequent image matching application. In view of these problems, this paper proposes a Back-Filtering PFA algorithm (BFPFA) which is based on the Improved Generalized Bistatic Equivalent Range Model (IGBERM). Constructing the combined compensating filter of space-variant phase error and geometric distortion, as well as reverse mapping interpolation, can realize the combined compensation of motion error, wavefront bending and geometric distortion in the process of oblique conversion, and obtain the SAR distance map without distortion, which is more conducive to the subsequent image matching applications. Finally, the simulations validate the effectiveness of the proposed algorithm.

Reverse pharmacophore mapping and molecular docking studies for discovery of GTPase HRas as promising drug target for bis-pyrimidine derivatives

BackgroundPyrimidine is an important pharmacophore in the field of medicinal chemistry and exhibit a broad spectrum of biological potentials. A study was carried out to identify the target protein of potent bis-pyrimidine derivatives using reverse docking program. PharmMapper, a robust online tool was used for identifying the target proteins based on reverse pharmacophore mapping. The murine macrophage (RAW 264.7) and human embryonic kidney (HEK-293) cancer cell line used for selectivity and safety study.MethodsAn open web server PharmMapper was used to identify the possible target of the developed compounds through reverse pharmacophore mapping. The results were analyzed and validated through docking with Schrodinger v9.6 using 10 protein GTPase HRas selected as possible target. The docking studies with Schrödinger validated the binding behavior of bis-pyrimidine compounds within GTP binding pocket. MTT and sulforhodamine assay were used as antiproliferative activity.Results and discussionThe protein was found one of the top scored targets of the compound 18, hence, the GTPase HRas protein was found crucial to be targeted for competing cancer. Toxicity study demonstrated the significant selectivity of most active compounds, 12, 16 and 18 showed negligible cell toxicity at their IC50 concentration.ConclusionFrom the results, we may conclude that GTPase HRas as a possible target of studied bis-pyrimidine derivatives where the retrieved information may be quite useful for rational drug designing.

A novel image encryption scheme based on 3D bit matrix and chaotic map with Markov properties

Based on 3D cat map, reverse 3D cat map and an improved class of chaotic maps with Markov properties, an effective bit-level image encryption scheme is proposed. Firstly, we convert the plain-image into binary matrix, and use the sum of all bits in the binary matrix as a part of secret keys to resist chosen-plaintext attack and known-plaintext attack. Secondly, we design a mapping which maps a random bit position to another random bit position rather than using traditional sequential visiting the plain-image. Thirdly, a chaotic map with Markov properties is used in the diffuse process. This kind of chaotic map has good chaotic natures than the Logistic map, which keeps the uniformity and low autocorrelation. The results of simulation and security analysis show that the proposed image encryption scheme is able to resist various attacks and has excellent encryption performance.

Mapping of the functional anatomy of lymphatic drainage to the axilla in early breast cancer: A cohort study of 933 cases

IntroductionThe aims of this study were to investigate the correlation between lymphatic drainage and the sentinel lymph node (SLN) status of the subregions in the context of the clinic-pathological parameters of the tumour and the coverage of the axillary volumes by standard and high tangential fields (STgF and HTgF) for whole breast radiotherapy and axillary reverse mapping (ARM). Patients and methods933 women with early breast cancer and clinically negative axillary status underwent breast surgery and SLN biopsy followed by axillary lymph node dissection in SLN-positive cases. The subregional localisation of the SLN(s) was registered and statistically analysed with the clinic-pathological characteristics of the breast tumour. In node-positive patients treated with breast-conserving therapy in whom the SLNs were found in the anterior or posterior axillary subregions, the axillary volumes were contoured using the Radiation Therapy Oncology Group contouring atlas (n = 61). ResultsIn 91.1% (n = 797) of the cases, the SLN appeared in the anterior, posterior or central subregions.Using HTgF, Level I or II were completely covered in 65.6% (40/61) and 6.6% (4/61) of the cases, respectively. With STgF, the complete coverage was 0% for both levels.6.8% (n = 63) of all cases had one positive lymph node in the expected ARM lymph node regions. DiscussionA SLN is more than likely to be present in the anterior, posterior and central axillary subregions. Tangential fields allow only limited coverage of the axillary volumes. Preserving the lateral subregion during ARM may increase the possibility of understaging.

Reverse Axillary Mapping and Lymphaticovenous Bypass: Lymphedema Prevention through Enhanced Lymphatic Visualization and Restoration of Flow

Schwarz, Graham S. MD, FACS; Grobmyer, Stephen R. MD, FACS; Djohan, Risal MD; Bernard, Steven MD; Cakmakoglu, Cagri MD; Knackstedt, Rebecca MD; Yanda, Courtney MPH; Valente, Stephanie A. DO, FACS Author Information

Reverse Mapping Algorithm for Multi-scale Numerical Simulation of Polylactic Acid

An algorithm is proposed to convert the coarse-grained A-graft-B model of polylactic acid into the atomistic representation. In the A-graft-B model the atoms of the backbone are mapped onto A beads, which form the linear backbone of the coarse-grained macromolecule, the methyl groups are mapped onto B side pendants. The algorithm restores atomic positions based on positions of coarse-grained beads with the help of pre-defined chain fragments, called templates. The dimensions of the templates are adjusted by affine transformation to ensure coincidence of the backbone in coarse-grained and atomistic representation. The transition between coarse-grained and atomistic models conserves information about the fine structure of polymer chains. The restored configurations are suitable for further molecular-dynamic simulations. Both atomistic and coarse-grained representations require standard GROMACS software. The algorithm can be used for reverse mapping of other A-graft-B polymer models.

Detection of seal and signature entities with hierarchical recovery based on watermark self embedding in tampered digital documents

A novel framework is proposed in this paper for detection of seal and signature entities with hierarchical recovery capability based on self-embedding watermarking. First of all, the entities of importance called authentication entities are identified in the documents. Once these entities are located, they are made secure via integrity check bits. The authentication is performed at the pixel level through three integrity check bits based on pixel value, location, and neighborhood. The recovery information from these authentication entities is extracted and embedded after encryption in multiple locations throughout the document. In case of tampering, the tampered regions are detected as well as localized and reverse mapping is performed to fetch the recovery information for reconstruction of the tampered regions. To validate the efficacy of the proposed framework, a number of experiments have been conducted with multiple documents and different attack scenarios. The imperceptibility of the watermarked and recovered documents has been evaluated using Peak Signal to Noise Ratio (PSNR) and Structural Similarity Index (SSIM) metrics.

3D PEE mapping based reversible data hiding for color images

The performance of prediction-error expansion (PEE) for reversible data hiding (RDH) is excellent. 2D and 3D PEE has a great improvement than the conventional PEE. However, the PEE-based method used in each channel of a color image cannot make full use of the correlation among three channels. In the paper, a reversible data hiding algorithm based on 3D PEE mapping is proposed. Firstly, a prediction-error triple is generated from three channels of a color image. Next, the prediction error triples can shift freely in 3D space. Finally, specific error triples have been shifted to embed secret data and other triples are expanded to make room for data embedding. By using the proposed reversible 3D PEE mapping, the inter-correlation of RGB channels is better exploited. Extensive experimental results demonstrate that the proposed algorithm outperforms the traditional RDH methods for color images.

Breast cancer-related lymphedema: risk factors, precautionary measures, and treatments.

Breast cancer-related lymphedema (BCRL) is a negative sequela of breast cancer treatment, and well-established risk factors include axillary lymph node dissection (ALND) and regional lymph node radiation (RLNR). BCRL affects approximately 1 in 5 patients treated for breast cancer, and it has a significant negative impact on patients' quality of life after breast cancer treatment, serving as a reminder of previous illness. This paper is a comprehensive review of the current evidence regarding BCRL risk factors, precautionary guidelines, prospective screening, early intervention, and surgical and non-surgical treatment techniques. Through establishing evidence-based BCRL risk factors, researchers and clinicians are better able to prevent, anticipate, and provide early intervention for BCRL. Clinicians can identify patients at high risk and utilize prospective screening programs, which incorporate objective measurements, patient reported outcome measures (PROM), and clinical examination, thereby creating opportunities for early intervention and, accordingly, improving BCRL prognosis. Innovative surgical techniques that minimize and/or prophylactically correct lymphatic disruption, such as axillary reverse mapping (ARM) and lymphatic-venous anastomoses (LVAs), are promising avenues for reducing BCRL incidence. Nonetheless, for those patients with BCRL who remain unresponsive to conservative methods like complete decongestive therapy (CDT), surgical treatment options aiming to reduce limb volume or restore lymphatic flow may prove to be palliative or corrective. It is only through a strong team-based approach that such a continuum of care can exist, and a multidisciplinary approach to BCRL screening, intervention, and research is therefore strongly encouraged.

Reverse screening on indicaxanthin from Opuntia ficus-indica as natural chemoactive and chemopreventive agent

Indicaxanthin is a bioactive and bioavailable betalain pigment extracted from Opuntia ficus indica fruits. Indicaxanthin has pharmacokinetic proprieties, rarely found in other phytochemicals, and it has been demonstrated that it provides a broad-spectrum of pharmaceutical activity, exerting anti-proliferative, anti-inflammatory, and neuromodulator effects. The discovery of the Indicaxanthin physiological targets plays an important role in understanding the biochemical mechanism. In this study, combined reverse pharmacophore mapping, reverse docking, and text-based database search identified Inositol Trisphosphate 3-Kinase (ITP3K-A), Glutamate carboxypeptidase II (GCPII), Leukotriene-A4 hydrolase (LTA4H), Phosphoserine phosphatase (HPSP), Phosphodiesterase 4D (PDE4D), AMPA receptor (GluA3 and GluA2 subunits) and Kainate receptor (GluK1 isoform) as potential targets for Indicaxanthin. These targets are implicated in neuromodulation, and inflammatory regulation, normally expressed mostly in the CNS, and expressed (or overexpressed) in cancer tissues (i.e. breast, thyroid, and prostate cancer cells). Moreover, this study provides qualitative and quantitative information about dynamic interactions of Indicaxanthin at the binding site of target proteins, through molecular dynamics simulations and MM-GBSA.

Joint reconstruction of rest/stress myocardial perfusion SPECT

Myocardial perfusion imaging (MPI) using rest/stress single photon emission computed tomography (SPECT) allows non-invasive assessment of reversible cardiac perfusion defects. Conventionally, reversible defects are identified using a difference image, called reversible map, obtained by subtracting the stress image from the rest image after registration and normalization of the two images. The identification of reversible defects using the conventional subtraction method is however limited by noise. We propose to jointly reconstruct rest and stress projection data to directly obtain the reversible map in a single reconstruction framework to improve the detectability of reversible defects. To evaluate the performance of the proposed method, we performed phantom studies to mimic reversible defects with different levels of severity and doses. As compared to the conventional subtraction method, the joint method yielded reversible maps with much lower noise and improved defect detectability. At a normal clinical dose level, the joint method improved the signal to noise ratio (SNR) of defect contrast in reversible maps from 13.2 to 66.4, 9.7 to 35.0, 6.1 to 13.2, and 3.1 to 6.5, for defect to normal myocardium concentration ratios of 0%, 25%, 50%, and 75%, respectively. The SNRs obtained using the joint method were improved from 6.1 to 13.2, 3.9 to 9.4, 3.0 to 8.0, and 2.1 to 7.1, for 100%, 75%, 50%, and 25% of the normal clinical dose as compared to the conventional subtraction method. To access clinical feasibility, we applied the joint method to a rest/stress SPECT MPI patient study. The joint method yielded a reversible map with much lower noise, translating into a much higher defect detectability as compared to the conventional subtraction method. Our results indicate that the joint method has the potential to improve radiologists’ performance for assessing defects in rest/stress SPECT MPI. In addition, the joint method can be used to reduce dose or imaging time.

Prior-Based Quantization Bin Matching for Cloud Storage of JPEG Images.

Millions of user-generated images are uploaded to social media sites like Facebook daily, which translate to a large storage cost. However, there exists an asymmetry in upload and download data: only a fraction of the uploaded images are subsequently retrieved for viewing. In this paper, we propose a cloud storage system that reduces the storage cost of all uploaded JPEG photos, at the expense of a controlled increase in computation mainly during download of requested image subset. Specifically, the system first selectively re-encodes code blocks of uploaded JPEG images using coarser quantization parameters for smaller storage sizes. Then during download, the system exploits known signal priors-sparsity prior and graph-signal smoothness prior-for reverse mapping to recover original fine quantization bin indices, with either deterministic guarantee (lossless mode) or statistical guarantee (near-lossless mode). For fast reverse mapping, we use small dictionaries and sparse graphs that are tailored for specific clusters of similar blocks, which are classified via tree-structured vector quantizer. During image upload, cluster indices identifying the appropriate dictionaries and graphs for the re-quantized blocks are encoded as side information using a differential distributed source coding scheme to facilitate reverse mapping during image download. Experimental results show that our system can reap significant storage savings (up to 12.05%) at roughly the same image PSNR (within 0.18 dB).

Axillary reverse mapping (ARM): where to go.

In the past decades, breast surgeons have changed the clinical practice in the surgical treatment of breast cancer, by performing sentinel lymph node biopsy (SLNB) instead of performing axillary lymph node dissection (ALND) in axillary lymph node clinically negative breast cancer patients. ALND can also be avoided in SLN-positive patients who meet the Z-0011 criteria. However, the postoperative complications of SLNB and ALND, such as the secondary upper extremity lymphedema, are common and need effective solutions to prevent as soon as possible. The axillary reverse mapping (ARM) technique has been developed to map and preserve arm lymphatic drainage during ALND and/or SLNB, thereby minimizing arm lymphedema. However, the success of ARM in reducing lymphedema has not been exactly determined. If ARM can be confirmed to be both effective and oncologically safe in preventing lymphedema, this technique should be recommended in the management of breast cancer treatment.

Light storage for one second in room-temperature alkali vapor

Light storage, the controlled and reversible mapping of photons onto long-lived states of matter, enables memory capability in optical quantum networks. Prominent storage media are warm alkali vapors due to their strong optical coupling and long-lived spin states. In a dense gas, the random atomic collisions dominate the lifetime of the spin coherence, limiting the storage time to a few milliseconds. Here we present and experimentally demonstrate a storage scheme that is insensitive to spin-exchange collisions, thus enabling long storage times at high atomic densities. This unique property is achieved by mapping the light field onto spin orientation within a decoherence-free subspace of spin states. We report on a record storage time of 1 s in room-temperature cesium vapor, a 100-fold improvement over existing storage schemes. Furthermore, our scheme lays the foundations for hour-long quantum memories using rare-gas nuclear spins.

Direct Structural Annotation of Membrane Protein Aggregation Loci using Peptide-Based Reverse Mapping.

Membrane protein aggregation is associated with neurodegenerative diseases. Despite remarkable advances to map protein aggregation, molecular elements that drive the structural transition from functional to amyloidogenic β-sheet polymers remain elusive. Here, we report a simple and reliable reverse-mapping method to identify the molecular elements. We validate our approach by obtaining molecular details of aggregation loci of human β-barrel nanopore ion channels that are vital for cell survival. By coupling bottom-up synthesis with time-resolved aggregation kinetics and high-resolution imaging, we identify molecular elements that switch folded channels to polymeric β-rich aggregates. We prove that intrinsic protein aggregation and amyloidogenicity does not depend on total hydrophobicity but on single residue differences in the primary sequence. Our method offers effective strategies for sequence-based design of aggregation inhibitors in biomedicine for neurodegenerative diseases.

Generalized Algorithm of Reverse Mapping Based SVPWM Strategy for Diode-Clamped Multilevel Inverters

This paper presents a reverse mapping based space vector pulse-width modulation strategy for five- and seven-level diode-clamped multilevel inverters. In this method, the space vector is expressed as a sum of a contender vector and an error vector. Here, the actual sector, which contains the tip of the reference space vector, needs not to be found. The vector nearest to the reference space vector is the contender vector. By calculating the vector difference of the contender vector from the reference vector, the error vector is determined. Using translation method, the error vector is translated to the origin of space vector diagram. There will be ( n –1) steps in space vector diagram for an n -level inverter. As the error vector amplitude will be less than one step of the space vector diagram, the two-level space vector method can be applied. To obtain a vector that is very close to the reference vector, the determined switching states can be added to the contender vector. This technique can be extended to any n -level multilevel inverter. The performance of five-level and seven-level diode-clamped multilevel inverters is presented using MATLAB/Simulink. The performance of inverters is evaluated by using induction motor load. The experimental results using field programmable gate array are presented for seven-level diode-clamped multilevel inverter.