Circular Fourier Research Articles

EFFECTIVE CLASSIFICATION OF KNEE OSTEOARTHRITIS USING MILITARY SCRUTOLF OPTIMIZATION-TUNED DCNN CLASSIFIER

Accurately identifying the various types of knee osteoarthritis aids in an accurate diagnosis. The unique kind and severity of osteoarthritis enable medical specialists to offer the best management and treatment plans. Knee osteoarthritis greatly affects the living style of people by causing higher anxiety, mental issues, and health issues. Early treatment is possible because of early prediction, which may improve patient outcomes. Individuals may be able to prevent or postpone the development of knee osteoarthritis symptoms. An efficient categorization method for knee osteoarthritis employing the Military Scrutolf optimization-tuned deep Convolutional Neural Network (MSO-DCNN) and the advancement of study into this crippling disorder and the improvement of diagnosis, therapy, resource allocation, and disease monitoring are all made possible by the CNN classifier. The preprocessing of the data, which is carried out in three parts and involves the Circular Fourier Transform, Histogram Equalization, and Multivariate Linear Function, also contributes significantly to the success of this study. The proposed MSO technique, which improves convergence time and fine-tunes the classifier’s weight and Bias parameters, was built utilizing the features of military dogs and scrutolf to assist in getting increased seeking and hunting qualities. The MSO-tuned DCNN classifier’s adjusted weights and bias to give more effective desired classification results without using up more time or storage. By examining the performance measures and comparing the existing techniques to the MDO-based DCNN, the suggested MSO-DCNN improved based on TP accuracy by 1.33%, f1 measure by 2.9%, precision by 0.8%, and recall by 2.905%.

Deep Convolutional Neural Network Classifier for Effective Knee Osteoarthritis Classification

Millions of people are affected by the disease Knee Osteoarthritis, and the prevalence of the condition is steadily increasing. Knee osteoarthritis has a significant impact on people's lives by generating increased worry, mental health disorders, and physical problems. Early detection of knee osteoarthritis is critical for decreasing disease consequences, and numerous studies are being conducted to classify knee osteoarthritis. In this study, the deep CNN classifier is used to classify knee osteoarthritis, which effectively extracts the features required for disease classification more efficiently. The preprocessing of the data, which is done in three processes such as Circular Fourier Transform, Multivariate Linear Function, and Histogram Equalization, is particularly important in this research since it aids in obtaining more efficient information about the image. The deep CNN classifier's weights and bias deliver better and desired classification results while spending less time and storage. The proposed deep CNN classifier attained the Accuracy of 94.244%, F1 measure of 94.059%, Precision of 94.059%, Recall of 93.586%.

Effects of A\u03b2-derived peptide fragments on fibrillogenesis of A\u03b2

Amyloid β (Aβ) peptide aggregation plays a central role in Alzheimer’s disease (AD) etiology. AD drug candidates have included small molecules or peptides directed towards inhibition of Aβ fibrillogenesis. Although some Aβ-derived peptide fragments suppress Aβ fibril growth, comprehensive analysis of inhibitory potencies of peptide fragments along the whole Aβ sequence has not been reported. The aim of this work is (a) to identify the region(s) of Aβ with highest propensities for aggregation and (b) to use those fragments to inhibit Aβ fibrillogenesis. Structural and aggregation properties of the parent Aβ1–42 peptide and seven overlapping peptide fragments have been studied, i.e. Aβ1–10 (P1), Aβ6–15 (P2), Aβ11–20 (P3), Aβ16–25 (P4), Aβ21–30 (P5), Aβ26–36 (P6), and Aβ31–42 (P7). Structural transitions of the peptides in aqueous buffer have been monitored by circular dichroism and Fourier transform infrared spectroscopy. Aggregation and fibrillogenesis were analyzed by light scattering and thioflavin-T fluorescence. The mode of peptide-peptide interactions was characterized by fluorescence resonance energy transfer. Three peptide fragments, P3, P6, and P7, exhibited exceptionally high propensity for β-sheet formation and aggregation. Remarkably, only P3 and P6 exerted strong inhibitory effect on the aggregation of Aβ1–42, whereas P7 and P2 displayed moderate inhibitory potency. It is proposed that P3 and P6 intercalate between Aβ1–42 molecules and thereby inhibit Aβ1–42 aggregation. These findings may facilitate therapeutic strategies of inhibition of Aβ fibrillogenesis by Aβ-derived peptides.

Macrochirality of Self-Assembled and Co-assembled Supramolecular Structures of a Pair of Enantiomeric Peptides.

Although macrochirality of peptides’ supramolecular structures has been found to play important roles in biological activities, how macrochirality is determined by the molecular chirality of the constituted amino acids is still unclear. Here, two chiral peptides, Ac-LKLHLHLQLKLLLVLFLFLALK-NH2 (KK-11) and Ac-DKDHDHDQDKDL DVDFDFDADK-NH2 (KKd-11), which were composed entirely of either L- or D-amino acids, were designed for studying the chiral characteristics of the supramolecular microstructures. It was found that monocomponent KK-11 or KKd-11 self-assembled into right- or left-handed helical nanofibrils, respectively. However, when they co-assembled with concentration ratios varied from 1:9 to 9:1, achiral nanowire-like structures were formed. Both circular dichroism and Fourier transform infrared spectra indicated that the secondary structures changed when the peptides co-assembled. MD simulations indicated that KK-11 or KKd-11 exhibited a strong propensity to self-assemble into right-handed or left-handed nanofibrils, respectively. However, when KK-11 and KKd-11 were both presented in a solution, they had a higher probability to co-assemble instead of self-sort. MD simulations indicated that, in their mixtures, they formed nanowires without handedness feature, a good agreement with experimental observation. Our results shed light on the molecular mechanisms of the macrochirality of peptide supramolecular microstructures.

Study on the binding of sulfaclozine sodium monohydrate with bovine and human serum albumins using multi-spectroscopy and molecular docking

The interactions of sulfaclozine sodium monohydrate (SSM) with bovine and human serum albumins (BSA and HSA) were studied by multi-spectroscopy and molecular docking technique. Stern–Volmer analysis and fluorescence lifetime measurements suggested the quenching processes were static. According to the Fluorescence resonance energy transfer (FRET) theory, the binding distances were obtained indicating SSM interacted with BSA/HSA along with non-radiation energy conversion. Electrostatic attraction was the main force in keeping the stability of the compound based on thermodynamic parameters. Circular dichroism (CD), synchronous fluorescence and Fourier Transform infrared (FT-IR) spectra embodied the secondary structures of serum albumins were transformed by SSM. The site marker competitive and molecular docking measurements testified SSM bound to BSA/HSA at site I. In conclusion, the secondary structures of BSA/HSA were changed by SSM in the static fluorescence quenching processes with the non-radiation energy conversion. The binding sites were all located at site I and electrostatic attraction was the main force for the new compound. Communicated by Ramaswamy H. Sarma

Improving emulsion stability based on ovalbumin-carboxymethyl cellulose complexes with thermal treatment near ovalbumin isoelectric point

Ovalbumin (OVA) is an important protein emulsifier. However, it is unstable near the isoelectric point pH, which limits its applications in the food industry. Polysaccharides may be explored to tackle this challenge by improving its pH-dependent instability. In this work, carboxymethyl cellulose (CMC) was used as a model polysaccharide to mix with OVA near its isoelectric point (pH 4.7) with subsequent mild heating at 60 °C for 30 min. The molecular interactions between OVA and CMC were comprehensively studied via a series of characterizations, including turbidity, zeta potential, intrinsic fluorescence, surface hydrophobicity, circular dichroism (CD) spectra and Fourier transform infrared spectroscopy (FTIR). The droplet sizes of the emulsions prepared by OVA-CMC were measured to analyze emulsifying property and stability. The results indicated that free OVA was easily aggregated due to loss of surface charges, while complexing with CMC significantly inhibited OVA aggregation before and after heating owing to the strong electrostatic repulsion. In addition, OVA exposed more hydrophobic clusters after heating, which resulted in the growth of surface hydrophobicity. Altogether, the heated OVA-CMC complexes presented the best emulsifying property and stability. Our study demonstrated that complexing OVA with CMC not only greatly improved its physicochemical properties but also significantly enhanced its functionality as a food-grade emulsifying agent, expanding its applications in the food industry, as development of emulsion-based acidic food products.

A decision support tool for early detection of knee OsteoArthritis using X-ray imaging and machine learning: Data from the OsteoArthritis Initiative

This paper presents a fully developed computer aided diagnosis (CAD) system for early knee OsteoArthritis (OA) detection using knee X-ray imaging and machine learning algorithms. The X-ray images are first preprocessed in the Fourier domain using a circular Fourier filter. Then, a novel normalization method based on predictive modeling using multivariate linear regression (MLR) is applied to the data in order to reduce the variability between OA and healthy subjects. At the feature selection/extraction stage, an independent component analysis (ICA) approach is used in order to reduce the dimensionality. Finally, Naive Bayes and random forest classifiers are used for the classification task. This novel image-based approach is applied on 1024 knee X-ray images from the public database OsteoArthritis Initiative (OAI). The results show that the proposed system has a good predictive classification rate for OA detection (82.98% for accuracy, 87.15% for sensitivity and up to 80.65% for specificity).

Synthesis of 5-Fluorouracil conjugated LaF3:Tb3+/PEG-COOH nanoparticles and its studies on the interaction with bovine serum albumin: spectroscopic approach

The luminescent lanthanide-doped nanoparticles have gathered considerable attention in many fields especially in biomedicine. In this work, the lanthanum fluoride-doped terbium nanoparticles (LaF3:Tb3+ NPs) via simple chemical precipitation method has been synthesized and functionalized with polyethylene glycol. The size and the shape of the nanoparticles are confirmed using X-ray diffraction and transmission electron microscopy. The conjugation of 5-Fluorouracil (5-FU) and thus synthesized nanoparticles (NPs) were confirmed using various spectroscopic methods such as UV–Visible spectroscopy, fluorescence steady state, and excited state spectroscopy studies. The enhancement in fluorescence emission (λ = 543 nm) of drug-conjugated nanoparticles confirms the Vander Waals force of attraction due to F–F bonding between the drug and the nanoparticles. Further, the effects of 5FU-NPs in carrier protein were investigated using bovine serum albumin as a protein model. The 5FU–LaF3:Tb3+ nanoparticles binding is illustrated with binding constant and number of binding sites. The structural change of bovine serum albumin has been studied using circular dichroism and Fourier transform infrared spectroscopy analysis.

A Robust Adaptive Acoustic Echo Cancellation (AEC) for Hands-free Communications using a Low Computational Cost Algorithm in Frequency Domain

This study presents a new algorithm for cancelling the acoustic echo, which is a major problem for hands- free communications. The proposed adaptive Acoustic Echo Canceller algorithm is designed and developed using a digital signal processing technique in frequency domain. The main scope of this study is to implement this module, benefiting the advantage of circular convolution properties and Fast Fourier Transform (FFT) with high computation speed in frequency domain rather than adaptive algorithms Normalized Least Mean Square (NLMS) and Recursive Least Square (RLS) in time domain with high complexity, also the simplicity of the implementation using SIMULINK programming. The results obtained at the simulation level prove the module behavior for cancellation of echo for hands free communications using adaptive algorithm frequency domain. Nevertheless, our algorithm shows more performances in terms of convergence and complexity. Our algorithm has been verified using the ERLE criteria to measure the attenuation of the echo signal at the output of an AEC; at this level we obtained the best values according to IUT-T recommendation G.168.

Partial differential equation-based localization of a monopole source from a circular array

Wave source localization from a sensor array has long been the most active research topics in both theory and application. In this paper, an explicit and time-domain inversion method for the direction and distance of a monopole source from a circular array is proposed. The approach is based on a mathematical technique, the weighted integral method, for signal/source parameter estimation. It begins with an exact form of the source-constraint partial differential equation that describes the unilateral propagation of wide-band waves from a single source, and leads to exact algebraic equations that include circular Fourier coefficients (phase mode measurements) as their coefficients. From them, nearly closed-form, single-shot and multishot algorithms are obtained that is suitable for use with band-pass/differential filter banks. Numerical evaluation and several experimental results obtained using a 16-element circular microphone array are presented to verify the validity of the proposed method.

Calcium Binding to a Factor IX Fc Fusion Protein and Effects on Higher‐Order Structure

There is significant scope for more meaningful evaluation of higher-order structure in defining the quality of biopharmaceutical products [Bush L. 2010. Biopharm Int 23(4):14]. We have used isothermal titration calorimetry (ITC) to characterize the Ca(2+) -binding isotherm of a recombinant human factor IX Fc fusion protein (rFIXFc) and the parent recombinant human factor IX molecule (rFIX). Circular dichroism, intrinsic fluorescence, and Fourier transform infrared spectroscopies detected characteristic spectral changes that appear qualitatively consistent with the previously characterized behavior of the factor IX molecule. Sedimentation velocity and dynamic light scattering measurements were recorded in the presence and absence of Ca(2+) over the protein concentration range 1-10 mg/mL. ITC of Ca(2+) binding to rFIXFc reveals a distinctive exothermic-binding isotherm, which is interpreted as consistent with two high-affinity and approximately 14 lower-affinity Ca(2+) sites reported in the literature for human factor IX (Schmidt AE, Bajaj SP. 2003. Trends Cardiovasc Med 13(1):39-45). Analysis of accelerated degradation samples showed significant alterations in Ca(2+) binding, which correlates with significant loss of biopotency and fragmentation by gel chip capillary electrophoresis. Collectively, these data establish a close correspondence in the Ca(2+) -binding characteristics of rFIXFc and its parent rFIX molecule. The utility of ITC to provide a highly pertinent and selective biophysical signature of structure-function for a therapeutic factor protein is discussed.

Circularly Symmetric Light Scattering from Nanoplasmonic Spirals

In this paper, we combine experimental dark-field imaging, scattering, and fluorescence spectroscopy with rigorous electrodynamics calculations in order to investigate light scattering from planar arrays of Au nanoparticles arranged in aperiodic spirals with diffuse, circularly symmetric Fourier space. In particular, by studying the three main types of Vogel's spirals fabricated by electron-beam lithography on quartz substrates, we demonstrate polarization-insensitive planar light diffraction in the visible spectral range. Moreover, by combining dark-field imaging with analytical multiparticle calculations in the framework of the generalized Mie theory, we show that plasmonic spirals support distinctive structural resonances with circular symmetry carrying orbital angular momentum. The engineering of light scattering phenomena in deterministic structures with circular Fourier space provides a novel strategy for the realization of optical devices that fully leverage on enhanced, polarization-insensitive light-matter coupling over planar surfaces, such as thin-film plasmonic solar cells, plasmonic polarization devices, and optical biosensors.

Circular fourier analysis of modes of microstructured optical fibers with complex channel cross sections

A method for calculating the properties of microstructured optical fibers (MOFs) with complex channel cross sections has been developed and applied to studying leaky modes in MOFs with elliptical channels. It is demonstrated that MOFs can exhibit significantly anisotropic damping of the modes with orthogonal polarization.

10.1007/s11454-008-1016-3

An extension of the circular Fourier analysis of the mode field is presented that makes it possible to obtain a successively correctable solution to the scalar waveguide problem posed for 3D optical waveguides. The critical frequencies of rectangular and elliptic waveguides, as well as the characteristics of leaky modes in microstructural optical fibers formed by elliptical air channels, are studied.

An Analysis of an Optical Fiber with Two Inhomogeneous Sector Holes by Circular Fourier Expansion Method

In this paper, a fiber with two inhomogeneous sector holes around the core is proposed, and propagation characteristics of polarization maintaining region and single-polarization region are numerically analyzed by circular Fourier expansion method. In each case of the single-polarization region and the polarization maintaining region, a fiber is designed so as to satisfy the zero total dispersion at wavelength of 1.55μm. Then, the single-polarization bandwidth for the single-polarization region and the modal birefringence for the polarization maintaining region are examined as the specific characteristics in each region. In addition, the power concentrating into the core region and distributions of Poynting vector is also discussed.

Circular Fourier analysis of modes in optical waveguides under critical and supercritical conditions

An extension of the circular Fourier analysis of the mode field is presented that makes it possible to obtain a successively correctable solution to the scalar waveguide problem posed for 3D optical waveguides. The critical frequencies of rectangular and elliptic waveguides, as well as the characteristics of leaky modes in microstructural optical fibers formed by elliptical air channels, are studied.

DIMERIC SURFACTANT PROTEIN B PEPTIDE SP-B 1-25 IN NEONATAL AND ACUTE RESPIRATORY DISTRESS SYNDROME

Surfactant protein B (SP-B) is a constituent surfactant protein critical for normal lung function. Monomeric SP-B 1-25 (mSP-B 1-25) , a peptide based on the N-terminal domain of human SP-B, mixed in phospholipids partially restores lung function in surfactant-deficient animals. Because native SP-B is a homodimer, we synthesized and tested dimeric SP-B 1-25 (dSP-B 1-25) . Circular dichroism (CD) and Fourier Transform Infrared (FTIR) spectroscopy indicated that the secondary conformation of SP-B 1-25 was not significantly perturbed by dimerization. The effects on lung function were compared to phospholipids and Survanta in models of neonatal respiratory distress syndrome (RDS) and acute RDS (ARDS). Preterm rabbits born at 27 days of gestation received 100 mg surfactant / kg at birth and were ventilated for 1 hour with a tidal volume of 10 mL / kg. Dynamic compliance was monitored every 15 minutes and postmortem pressure-volume curves were measured. Adult rats were lavaged to induce surfactant deficiency, treated with 100 mg surfactant / kg, and ventilated for 2 hours. Lung function was assessed using arterial blood gases and dynamic compliance every 15 minutes and postmortem pressure-volume curves. Lung volumes in both models and oxygenation in the lavaged rats were consistently higher in the dSP-B 1-25 than in the Survanta and mSP-B 1-25 surfactant groups. The data suggest that dSP-B 1-25 is more efficient in restoring lung function in neonatal RDS and ARDS than mSP-B 1-25 surfactant.

Probing anterior segment kinetics with focally applied mydriatics.

The purpose of this study was to examine the effects of convectional flow and anterior segment configuration on drug kinetics. Mydriatics were applied focally at the limbus in order to produce sector dilation of the pupil. Subjects were tested with either tropicamide or phenylephrine, applied at the superior, temporal, inferior, or nasal limbus (or as a conventional drop). Changes in pupil form were analyzed by means of photography, digitization, and circular Fourier series representation. Both tropicamide and phenylephrine were found to produce sector dilation; however, phenylephrine was approximately twice as effective. Applications at the superior limbus were significantly less effective than applications at the inferior limbus. The results are interpreted in terms of anterior segment convectional flow, which is believed to play a substantial role in pharmacokinetics of the anterior segment.

Structural and biosensor analyses of a synthetic biotinylated peptide probe for the isolation of adenomatous polyposis coli tumor suppressor protein complexes.

Large numbers of colon tumors stem from mutations in the gene coding for the production of the adenomatous polyposis coli (APC) tumor suppressor protein. This protein contains a coiled-coil N-terminal domain that is known to be responsible for homodimerization. Previous work by others has led to the design of a specific 54-residue anti-APC peptide (anti-APCp1) that dimerizes preferentially with this domain. We have undertaken the chemical synthesis of a modified form of this peptide (anti-APCp2) that bears a biotin moiety at its N-terminus for use in subsequent ligand-binding analysis studies. The peptide was subjected to comprehensive chemical characterization to confirm its purity. Secondary structural analysis by circular dichroism spectroscopy and Fourier transform infrared spectroscopy indicated that the peptide could assume a wide range of potential conformations, depending upon the precise microenvironment. Significantly, a stable alpha-helical structure was generated when the solvent conditions supported intramolecular salt-bridge formation along the helix barrel. The biotinylated anti-APCp2 was immobilized onto a streptavidin sensor surface, in a specific orientation leaving all amino acids available to form a coiled structure. In one experiment, injection of colonic cell lysate extracts (LIM1215) onto a size-exclusion column resulted in the isolation of a high molecular mass protein peak (> 600 kDa) that reacted specifically with the immobilized anti-APCp2 on the biosensor surface. In another experiment, a high molecular mass protein (M(r) > 250 kDa on SDS-PAGE) could be specifically immunoprecipitated from this peak using either the anti-APCp2 peptide or an anti-APC polyclonal antibody. This demonstrates the specific interaction between the anti-APCp2 peptide and native APC and highlights the potential use of the former peptide in a multidimensional micropreparative chromatographic/biosensor/proteomic protocol for the purification of APC alone and APC complexed with different biopolymers in various cell lines, and stages of tumor development.

The structural and spectroscopic basis for modelling prion protein interactions

Mammalian prion diseases are characterised by an α‐helical to β‐sheet conformational change within the prion protein, that was originally established with circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy. Since prion disease is transmissible, significant effort has been aimed at establishing the molecular details of conformational change and the specificity that underpins infectivity. The structure determined for the carboxy‐terminal domain of the predominantly α‐helical form by nuclear magnetic resonance (NMR) provides a starting point for considering questions at the molecular level. However, elucidation of atomic detail for the β‐rich form is complicated by problems of protein solubility, and regions other than the carboxy‐terminal domain of the α‐rich form are likely to possess functionally significant, ordered domains in the presence of suitable ligands and solution conditions. Further spectroscopic analysis, particularly of polypeptide secondary structure, is playing a key role in constraining molecular modelling studies of prion protein folding and interactions. We present a review of this area of prion research.