Rational Interpolation: Jacobi’s Approach Reminiscence

We treat the interpolation problem {f(xj)=yj}j=1N for polynomial and rational functions. Developing the approach originated by C. Jacobi, we represent the interpolants by virtue of the Hankel polynomials generated by the sequences of special symmetric functions of the data set like {∑j=1Nxjkyj/W′(xj)}k∈N and {∑j=1Nxjk/(yjW′(xj))}k∈N; here, W(x)=∏j=1N(x−xj). We also review the results by Jacobi, Joachimsthal, Kronecker and Frobenius on the recursive procedure for computation of the sequence of Hankel polynomials. The problem of evaluation of the resultant of polynomials p(x) and q(x) given a set of values {p(xj)/q(xj)}j=1N is also tackled within the framework of this approach. An effective procedure is suggested for recomputation of rational interpolants in case of extension of the data set by an extra point.

Learning Course: Application of Gamification in Teaching Construction and Building Materials Subjects

This paper presents the experience of a group of Construction and Building Materials lecturers following the introduction of a new contest-based gamification activity aimed at improving interest and learning outcomes in the course. Students’ motivation is of key importance in utilizing educational activities for study and learning in the subject. Evaluation is essential and, therefore, the proposed action makes it possible to earn an extra point in the continuous evaluation that contributes to passing the subject. The outcomes obtained in the first academic year in which this learning contest was implemented allow us to conclude that the activity had positive effects on motivation and the learning process, as well as on the number of students passing the subject. The students’ opinion about the activity was very positive.

Indexing of American Football Video Using MPEG-7 Descriptors And MFCC Features

In this work, an application system is proposed to classify American Football Video shots. The application uses MPEG-7 motion and audio descriptors along with MEL Frequency Cepstrum coefficient features to classify the video shots into 4 categories, namely: Pass plays, Run plays, Field Goal/Extra Point plays and Kickoff/Punt plays. Fisher's Linear Discriminant Analysis is used to classify the 4 events, using a leave-one-out classification technique in order to minimize the sample set bias. For a database of 200 video shots taken from four different games, an overall system performance of 92.5% was recorded. In comparison to other American Football indexing systems, the proposed system performs 8% to 12% better. We have also proposed an algorithm that uses MPEG-7 motion activity descriptors and mean of the motion vector magnitudes, in a collaborative manner to detect the starting point of play events within video shots. The algorithm can detect starting points of the play with 83% accuracy.

Indexing of American Football Video Using MPEG-7 Descriptors And MFCC Features

In this work, an application system is proposed to classify American Football Video shots. The application uses MPEG-7 motion and audio descriptors along with MEL Frequency Cepstrum coefficient features to classify the video shots into 4 categories, namely: Pass plays, Run plays, Field Goal/Extra Point plays and Kickoff/Punt plays. Fisher's Linear Discriminant Analysis is used to classify the 4 events, using a leave-one-out classification technique in order to minimize the sample set bias. For a database of 200 video shots taken from four different games, an overall system performance of 92.5% was recorded. In comparison to other American Football indexing systems, the proposed system performs 8% to 12% better. We have also proposed an algorithm that uses MPEG-7 motion activity descriptors and mean of the motion vector magnitudes, in a collaborative manner to detect the starting point of play events within video shots. The algorithm can detect starting points of the play with 83% accuracy.

W-RESP: Well-Restrained Electrostatic Potential Derived Charges. Revisiting the Charge Derivation Model

ABSTRACTRepresentation of electrostatic interactions by a Coulombic pair-wise potential between atom-centered partial charges is a fundamental and crucial part of empirical force fields used in classical molecular dynamics simulations. The broad success of the AMBER force field family originates mainly from the restrained electrostatic potential (RESP) charge model, which derives partial charges to reproduce the electrostatic field around the molecules. However, description of the electrostatic potential around molecules by standard RESP may be biased for some types of molecules. In this study, we modified the RESP charge derivation model to improve its description of the electrostatic potential around molecules, and thus electrostatic interactions in the force field. In particular, we re-optimized the atomic radii for definition of the grid points around the molecule, redesigned the restraining scheme and included extra point charges. The RESP fitting was significantly improved for aromatic heterocyclic molecules. Thus, the suggested W-RESP(-EP) charge derivation model showed clear potential for improving the performance of the nucleic acid force fields, for which poor description of nonbonded interactions, such as underestimated base pairing, makes it difficult to describe the folding free energy landscape of small oligonucleotides.

P0485ASSOCIATION BETWEEN ANTI-GBM TITERS AND KIDNEY INFLAMMATION MEASURED BY A NEW ACTIVITY SCORE

Background and Aims Anti-glomerular basement membrane (anti-GBM) disease is an aggressive and rare glomerulopathy characterized by rapidly progressive loss of kidney function, leading to end stage kidney disease (ESKD) in a significant amount of cases. The main objective of our study was to determine whether anti-GBM titer correlated with the rate of activity in renal biopsy and long-term kidney survival in patients with anti-GBM, hence identifying patients who would potentially benefit from more intensive treatments. Method A retrospective analysis was performed on the cases of anti-GBM from our center that had both a positive biopsy and serology, from 2007 to 2019. Epidemiological data, anti-GBM levels on admission, kidney function at admission, discharge and follow-up, treatment and kidney biopsy findings were collected. All biopsies were reevaluated by a single, blinded pathologist and nephrologist. Based on a recent study by van Daalen et al, a chronicity and activity histopathological score was developed. The score was divided in glomerular and interstitial sections. In the glomerular section, a sclerotic pattern (>50% of glomeruli) was given 0 points in activity and 3 in chronicity, a mixed pattern was given 1 point in activity and chronicity, and a crescentic pattern (>50% with cellular crescents) was given 3 points in activity and 0 in chronicity. In the interstitial section, the presence of fibrosis and atrophy was given between 0 and 3 points in chronicity and the presence of tubulitis or interstitial infiltrate were given points in activity (0 to 1 and 0 to 3 respectively). The presence of neutrophils in the infiltrate was given one extra point in activity. Spearman correlation was performed between anti-GBM levels and our biopsy score. Results Twelve cases were identified, with a median Anti-GBM titer at admission of 292 U/mL (IQR 40-1517). Ten patients were treated with cyclophosphamide, 1 with rituximab plus cyclophosphamide and 1 with only rituximab. All patients received treatment with metilprednisona and plasma exchange with a median number of sessions of 8 (range: 6-12). Only one patient was not in ESKD during follow-up (35 months), so correlation with long-term kidney survival could not be performed. On the other hand, high antibody titers correlated with more activity on biopsy (correlation coefficient 0.592, p= 0.042) and less chronicity (correlation coefficient -0.657, p= 0.02). Conclusion These results suggest that patients who present with higher titers have more acute inflammation and less chronicity in renal parenchima, and therefore could benefit from more intensive treatment that changes the natural history of this aggressive disease. It would be interesting to study this score in larger and multicentric cohorts in order to produce more definitive conclusions.

MON-492 Should Isthmic Thyroid Nodule Be Included in ACR TI-RADS Points in Predicting Thyroid Cancer?

Background: Thyroid nodules are routinely evaluated with ultrasound. Isthmic nodules carry higher risk of malignancy (in press). Surgical studies suggest higher risk of metastasis from thyroid cancer located in isthmus region. In this study, we evaluate how adding an extra point for isthmic location to current ACR-TIRADS will affect the sensitivity and specificity to predict thyroid cancer. Methods: We performed a subanalysis of isthmic nodules contained in a retrospectively created database of 3313 adult patients from six referral centers with confirmed benign or malignant nodules. Sensitivity and specificity were calculated using the current ACR TI-RADS scoring system and compared to a system that would add an extra point based on nodule location in the isthmus. Results: There were 195 nodules in the isthmus (34 malignant). If a recommendation for FNA was considered a positive test result, the sensitivity and specificity would be 50% (17/34) and 61% (99/161) respectively using current ACR TI-RADS scoring. If an additional point was added the sensitivity and specificity would be 62% (21/34) and 36% (58/161) respectively. Adding the additional point would lead to detection of 4 additional malignant nodules at the cost of biopsying 41 additional benign nodules. If a recommendation for either FNA or follow-up ultrasound for 5 years was considered a positive test result, the sensitivity and specificity would be 82% (28/34) and 35% (56/161) respectively using current ACR TI-RADS scoring. If an additional point was added the sensitivity and specificity would be 94% (32/34) and 15% (24/161) respectively. Adding the additional point would lead to detection of 4 additional malignant nodules at the cost of either biopsying or following 32 additional benign nodules. Conclusions: Isthmic nodules are more likely to be malignant than nodules in other locations. When using the ACR TI-RADS, adding a point for isthmic nodules improves detection of cancer with a moderate increase in the rate of FNA and follow-up of benign nodules. Given the higher risk of extra thyroidal extension and nodal metastases for isthmic cancers, this tradeoff between sensitivity and specificity may be acceptable and should be considered when dealing with nodules in the isthmus. Keywords: thyroid nodule, ACR TI-RADS, location, isthmus, thyroid cancer

A Modified Mutation-Sensitive On/Off Switch and Its Application in B-Raf Proto-Oncogene Hotspot Mutation Assay

The combination of phosphorothioate-modified primer and high-fidelity DNA polymerase constitute a mutation sensitive on/off switch. Herein, a modified mutation-sensitive on/off switch was designed with an extra point mutation at 5′ far away from the 3′ of the phosphorothioate modified primer to test the power of the new enzymes: Phusion, Q5 and Phanta UC polymerases. A modified on/off switch with the introduction of an extra point mismatched nucleotide at –8 from the 3′ terminus, and the use of Phanta UC Super-fidelity DNA polymerase has been confirmed to be highly sensitive and specific as compared to those without the 5′ artificial mismatched nucleotide, when applied in circulating tumor DNA (ctDNA) analysis of BRAF hotspot mutation.

Tackling Halogenated Species with PBSA: Effect of Emulating the σ-Hole

<div>To model halogen bond phenomena using classical force fields, an extra-point (EP) of charge is frequently introduced at a given distance from the halogen (X) to emulate the σ-hole. The resulting molecular dynamics (MD) trajectories can be used in subsequent molecular mechanics (MM) combined with Poisson–Boltzmann and surface area calculations (MM PBSA) to estimate protein–ligand binding free energies (∆G_bind). While EP addition improves the MM/MD description of halogen-containing systems, its effect on the calculation of solvation free energies (∆G_solv) using the PBSA approach is yet to be assessed. As the PBSA calculations depend, among other parameters, on the empirical assignment of radii (PB radii), a problematic issue arises since standard halogen radii are smaller than the typical X· · · EP distances (usually corresponding to R_min), thus placing the EP within the solvent dielectric. Herein, we performed a comprehensive study on the performance of PBSA (using three different setups) in the calculation of ∆Gsolv values for 142 halogenated compounds (bearing Cl, Br, or I) for which the experimental values are known. By conducting an optimization (minimizing the error against experimental values), we provide a new optimized set of halogen PB radii, for each PBSA setup, that should be used when the EP is located at R min in the context of GAFF. A simultaneous optimization of PB radii and X· · · EP distances shows that a wide range of distance/radius pairs can be used without significant loss of accuracy, therefore laying the basis for expanding this halogen radii optimization strategy to other force fields and EP implementations. As ligand ∆G_solv estimation is an important term in the determination of protein–ligand ∆G_bind , this work is particularly relevant in the framework of structure-based virtual screening and related computer-aided drug design routines.</div>

Tackling Halogenated Species with PBSA: Effect of Emulating the σ-Hole

<div>To model halogen bond phenomena using classical force fields, an extra-point (EP) of charge is frequently introduced at a given distance from the halogen (X) to emulate the σ-hole. The resulting molecular dynamics (MD) trajectories can be used in subsequent molecular mechanics (MM) combined with Poisson–Boltzmann and surface area calculations (MM PBSA) to estimate protein–ligand binding free energies (∆G_bind). While EP addition improves the MM/MD description of halogen-containing systems, its effect on the calculation of solvation free energies (∆G_solv) using the PBSA approach is yet to be assessed. As the PBSA calculations depend, among other parameters, on the empirical assignment of radii (PB radii), a problematic issue arises since standard halogen radii are smaller than the typical X· · · EP distances (usually corresponding to R_min), thus placing the EP within the solvent dielectric. Herein, we performed a comprehensive study on the performance of PBSA (using three different setups) in the calculation of ∆Gsolv values for 142 halogenated compounds (bearing Cl, Br, or I) for which the experimental values are known. By conducting an optimization (minimizing the error against experimental values), we provide a new optimized set of halogen PB radii, for each PBSA setup, that should be used when the EP is located at R min in the context of GAFF. A simultaneous optimization of PB radii and X· · · EP distances shows that a wide range of distance/radius pairs can be used without significant loss of accuracy, therefore laying the basis for expanding this halogen radii optimization strategy to other force fields and EP implementations. As ligand ∆G_solv estimation is an important term in the determination of protein–ligand ∆G_bind , this work is particularly relevant in the framework of structure-based virtual screening and related computer-aided drug design routines.</div>