Disk Thickness Research Articles

Early diagnosis of sickle cell retinopathy by using ocular coherence tomography in pediatric population (7-18 years) in central India.

Sickle cell disease (SCD) is the commonest inherited blood disorder leading to complications occurring due to vaso-occlusion including sight-threatening retinopathy. Retinopathy can be managed if diagnosed early and vision loss can be prevented. Since, very less data are available from India, hence, this study was conducted in children (7-18 years) with SCD to diagnose retinopathy by using ocular coherence tomography (OCT) in subclinical stages. This cross sectional single-center study was performed in 7-18 years age group children with SCD without any visual symptoms. Enrolled participants underwent complete ophthalmological examination including macula and optic disc thickness measurements using Cirrus HD-OCT and results were analyzed. Among 55 participants, none had visual impairment. Significant fundoscopy finding (nonproliferative sickle cell retinopathy/NPSR) was found in three patients (5.4%), thinning of central macula in four patients (7.27%), inner macula thinning in eight patients (14.5%), outer macula thinning in one patient (1.81%), retinal nerve fiber layer thinning in five patients (9%), ganglion cell layer to inner plexiform layer thinning in eight patients (14.54%). Overall NPSR was found in 5.4% patients detected with fundoscopy, whereas retinal layer thinning was found in 14 patients (25.4%) using OCT. Despite of the significant prevalence of SCR, it is still underdiagnosed complication, leading to thinning of the retina from early ages; thus, its early diagnosis by regular screening using newer diagnostic methods can prevent progression to sight-threatening complications and provide better quality of life for these patients.

Simple numerical X-ray polarization models of reflecting axially symmetric structures around accreting compact objects

ABSTRACT We present a series of numerical models suitable for X-ray polarimetry of accreting systems. First, we provide a spectropolarimetric routine that integrates reflection from inner optically thick walls of a geometrical torus of arbitrary size viewed under general inclination. In the studied example, the equatorial torus is illuminated by a central isotropic source of X-ray power-law emission, representing a hot corona. Nearly neutral reprocessing inside the walls is precomputed by Monte Carlo code stokes that incorporates both line and continuum processes, including multiple scatterings and absorption. We created a new xspec model, called xsstokes, which in this version enables efficient X-ray polarimetric fitting of the torus parameters, observer’s inclination and primary emission properties, interpolating for arbitrary state of primary polarization. Comparison of the results to a Monte Carlo simulation allowing partial transparency shows that the no-transparency condition may induce different polarization by tens of per cent. Allowing partial transparency leads to lower/higher polarization fraction, if the resulting polarization orientation is perpendicular/parallel to the rotation axis. We provide another version of xsstokes that is suitable for approximating nearly neutral reflection from a distant optically thick disc of small geometrical thickness. It assumes local illumination averaged for a selected range of incident angles, representing a toy model of a diffuse corona of various physical extent. Assessing both xsstokes variants, we conclude that the resulting polarization can be tens of per cent and perpendicularly/parallelly oriented towards the rotation axis, if the reflecting medium is rather vertically/equatorially distributed with respect to a compact central source.

Winding Response under Difference Effective Inductance for Single Phase High Voltage Transformer

Early studies of transformer winding parameters were focused on the determination via its physical dimensions and empirical formulas. In most cases it is divided into several parts namely coil section pairs, coils distance, disc coils diameter and thickness of insulation. Maxwell’s equations are often the solution to the problem, which satisfy related boundary conditions between conductors for mutual inductance and capacitor equations. Such solutions often led to errors and hence its mathematical model. To counter the problem, it was suggested that such approximations must be conducted with experimental model windings at the same time. Frequency domain measurements and time domain measurements can be conducted to effectively determine these parameters. This in turn will investigate the behaviour of transformer winding electromagnetic transient at high frequency. From theoretical point of view, predominantly capacitive winding model often considered to represent its behaviour at high frequency and will give the results of its initial distribution. Under this consideration, a single phase plain winding is considered for investigation. A single rectangular wave was considered to represent infinitive impinge incident wave, injected at one end of transformer winding and the measured response signals of the wavetail were considered for measurement. The experimental response and modelling results were compared and proved to have high agreement between the two.

A Self‐Consistent Model of Radial Transport in the Magnetodisks of Gas Giants Including Interhemispheric Asymmetries

AbstractOutward transport of plasma in the inner and middle magnetospheres of gas giants results from an interplay between mass loading from the inner dominant mass sources (volcanic moons), flux tube interchange in the centrifugally unstable magnetospheric plasma disk, turbulent heating of the plasma, and coupling between the equatorial plasma and the planetary upper atmosphere through magnetic field‐aligned current loops and/or Alfvén waves. We present a new analytical formalism describing large scale transport in gas giant systems, combining two historical approaches: radial diffusion of mass and energy through flux tube interchange, and angular momentum transport through corotation enforcement. Under the hypotheses of axisymmetry, steady‐state, and multi‐fluid plasma, we provide transport equations for total contents of flux tubes. They feature new transport parameters accounting for the latitudinal extent of the disk, and self‐consistently include field‐aligned potential drops in the magnetosphere‐ionosphere coupling. Our general formalism has a wealth of applications, two of which are presented, corresponding to the cases of the two gas giants: the effect of interhemispheric asymmetries in the resistive and magnetic properties between the northern and southern ionospheres on the transport of angular momentum at Jupiter, and the influence of the plasma disk thickness on transport at Saturn. We apply our formalism to derive ionospheric parameters and reproduce the Juno and Cassini data. Further work will allow for more complete numerical solutions of our equations, with the aim of capturing the broad complexity of fast rotating magnetospheric systems which can be found inside and outside the Solar System.

Comparison of magnetized thick disks around black holes and boson stars

Boson stars are considered as promising candidates for black hole mimickers. Similar to other compact objects they can form accretion disks around them. The properties of these disks could possibly distinguish them from other compact objects like black holes in future observations. Retrograde thick disks around boson stars and the influence of strong magnetic fields on them were already studied and it was shown that they can harbor very distinct features compared to black hole disks. However, the case of prograde thick disks is mostly unexplored, since they may appear much more similar to black hole disks. In this work we will investigate similarities and differences regarding prograde thick disks around non-selfinteracting rotating boson stars and rotating black holes. We assume thereby a polytropic equation of state and a constant specific angular momentum distribution of the disks. We classify the various conceivable boson star and black hole solutions by a dimensionless spin parameter a and compare their corresponding disk solutions. The influence of toroidal magnetic fields on the disks is analyzed by selected disk properties, as the rest-mass density distribution and the Bernoulli parameter. Disk solutions are characterized by their degree of magnetization represented by the magnetization parameter βmc\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta _{mc}$$\\end{document}. We found that strong magnetic fields can strengthen the differences of disk solutions or oppositely even lead to a correlation in disk properties, depending on the spin parameter of the boson star and black hole solutions. We identify the vertical thickness of the boson star disks as the main differentiating factor, since for most solutions the vertical density distribution is far more outreaching for boson star disks compared to black hole disks.

In Vitro Characterization of Poly(Ethylene Glycol) Dimethacrylate-Nanofibrillated Cellulose as an Injectable Biomaterial for Herniated Nucleus Pulposus Substitute

Highlights:1. Novel synthetic biopolymer hydrogels were successfully prepared from pristine poly(ethylene glycol) dimethacrylate (PEGDMA) and nanofibrillated cellulose (NFC) using the photopolymerization method.2. PEGDMA-NFC biocomposite hydrogel can be developed as an affordable biomaterial for herniated nucleus pulposus substitute, with the potential to meet clinical application standards. Abstract Herniated nucleus pulposus develops when the intervertebral disc portudes through the annulus fibrosus due to the rupture of the annulus fibrosus or a decrease in proteoglycans. Hydrogel implant material can be injected into the disc space to restore disc thickness caused by disc degeneration with minimal invasiveness. This study aimed to characterize poly(ethylene glycol) dimethacrylate-nanofibrillated cellulose (PEGDMA-NFC) in vitro as a potential biomaterial for herniated nucleus pulposus substitute. This study utilized PEGDMA-NFC to treat first-degree herniated nucleus pulposus using the photopolymerization method. PEGDMA was selected because of its hydrophilic ability to produce hydrogel. The addition of NFC to the PEGDMA precursor was expected to show mechanical properties as a hydrogel bio composite candidate. The characterization of PEGDMA-NFC was conducted using three tests: Fourier-transform infrared spectroscopy (FTIR), viscosity assessment, and an in vitro injection testing model. The normal distribution of the data was analyzed using the Kolmogorov-Smirnov test, while the homogeneity was assessed using Levene's test. Homogenous and normally distributed data were analyzed using a one-way analysis of variance (ANOVA) with a p-value of <0.05. The explored concentrations of PEGDMA-NFC included a ratio of 1:0 for the control samples and ratios of 1:0.5 (K1), 1:0.75 (K2), and 1:1 (K3) for the experimental samples. The FTIR analysis revealed the presence of various functional groups in PEGDMA-NFC, indicating its potential classification as a hydrogel biomaterial. The characterization data showed that the K3 sample yielded the most favourable outcome with a viscosity value of 74.67 dPa·s. From the in vitro injection testing result, the addition of NFC demonstrated that the hydrogel would not rupture when released from the mold. The hydrogel could be injected with an 18 gauge needle. The statistical analysis results showed a significant difference among the samples (p<0.05). This study concludes that the PEGDMA-NFC hydrogel biocomposite can be effectively applied in herniated nucleus pulposus cases.

A parametric study on the elastic limit stresses of rotating variable thickness orthotropic disk

This paper investigates the stress fields at the onset of plastic yield of variable thickness rotating orthotropic disk, which is rigidly fixed on an inclusion. In the analytical modeling of the problem, two different analytical solution methods have been displayed where small deformations have been considered with the application of plane stress conditions. Well-known power law is considered for the disk's thickness variation, and Hill’s yield criterion is applied to obtain the elastic limits. Four parameters have been utilized while analyzing the limit fields: geometric parameter to manipulate the disk thickness, orthotropy parameter from the ratio between Young's modulus in radial and tangential directions, and two parameters owing to the applied yield criteria. The effects of these parameters on the limit fields have been comprehensively examined in the numerical examples, and possible outcomes have been discussed. Additionally, using Autodesk Inventor Nastran, finite element solution of the disk is generated, analytical and numerical results have been compared, and consequently, closely matching results have been achieved.

Analysis of clinical changes and magnetic resonance imaging features of 37 patients with temporomandibular joint disc condylar complex with anterior disc displacement without reduction.

This study aims to investigate clinical outcomes, imaging changes, and age differences with regard to temporomandibular joint disc condylar complex with anterior disc displacement without reduction (ADDWoR). A total of 37 patients (45 lateral joints) with ADDWoR who were admitted to The First Affiliated Hospital of Zheng Zhou University from January 2016 to June 2023 were selected. The patients were composed of 4 males and 33 females and had an average age of 23.5 years. The average course of the disease was 14.4 months. Clinical and magnetic resonance imaging (MRI) data were collected at the end of initial diagnosis and follow-up, and the length and thickness of the articular disc, the angle of the disc condyle, and the height of the condyle were measured. The statistical significance of the changes was assessed using SPSS 25.0 software package. At the end of follow-up, disc displacement in three patients (three lateral joints) was healed. Approximately 48.4% of the patients felt that limitation of mandibular movement was not alleviated; 58.3% of patients reported that pain during mouth opening was not reduced; 54.5% reported pain while chewing; 33.3% of the patients showed facial deviation, and only one showed remission. The mean disk-condyle angle increased from 61.63° to 67.81°. The average length of articular disc shortened from 8.20 mm to 7.27 mm, and the height of the condyle significantly decreased from 23.17 mm to 22.76 mm (P<0.05). The absorption ratio of the condyle increased, and no significant differences in the changes of joint soft and hard tissues between the adolescent and adult groups (P>0.05). In different age groups of patients with ADDWoR, clinical symptoms cannot be completely relieved. The disc is anteriorly displaced and shortens, condylar height decreases, and secondary facial asymmetry and mandibular retraction occur.

Asymmetric two-dimensional poroelastic analysis of heterogeneous smart discs considering hygrothermal loading

The objective of this study is to examine through the finite element method the impacts of employing two-dimensional (2D) properties grading on the behaviors of piezoelectric sensors/actuators due to their significance. These structures are modeled as variable thickness discs and are assumed to be exposed to simultaneous asymmetric loading conditions (thermal, hygral, electrical, and mechanical loads). Results demonstrate that the 2D grading is superior compared to the conventional one-dimensional grading for reducing the von Mises stress. The reduction reached, for instance, 8.3% allowing further increase of loading and/or safety. Also, the change of the displacement is varied between −4.5% and 31% depending on the considered grading pattern, and thus can be controlled to a desired value which helps to improve the sensing and actuating functionality for certain requirements. The study also examines the effects of porosity, and the results are compared to nonporous discs. Reductions of the maximum compressive tangential stress and von Mises stress reached 79.75% and 33.6%, respectively at specific porosity distribution patterns and volume fractions. These findings have significant implications for the manufacturing of smart structures, enabling them to operate in severe working conditions with better sensing and actuating capabilities than previously possible.

Effect of cast-iron disc thickness on the reliability of tribological data from pin-on-disc test: Case study of brake friction materials

For braking system, rubbing between disc and brake pad generates heat, physical transformation on the contact, and activates many complex solicitations. Therefore, researchers used reduced scale testing to evaluate tribological and thermomechanical performance of friction composite. The pin-on-disc configuration of the tribometer is considered the better solution to reproduce these generated transformation and friction evolution. However, if the pin geometry is chospaden based on representative elementary volume (REV) approach, no research has investigated and justified the choice of the disc geometry and thickness. In this research work, an examination of the critical disc thickness is discussed, highlighting its substantial impact on the friction-wear behavior during brake application. For that, four disc thicknesses were tested, varying on thickness values (10, 15, 20, and 22 mm). Through this experiment, the friction coefficient evolution as function of braking numbers and sliding duration was studied while maintaining pressure and sliding velocity constant. Wear and temperature rise are identified for each disc thickness situation. A 3D thermal model is employed also to simulate the heat conduction and dissipation in brake system for various disc thickness. The temperature predictions are carried out using Ansys software. Experimental investigation presented the effect of the thickness on the friction stability, particularly at high temperature. Numerical results highlight the effect of reducing the thickness of the disc on the kinetic temperature rise through a rapid increase in disc temperature. The thickness modification used for the brake disc enhances the resulted thermal response and tribological brake pad performance, and consequently enhance the reliability of tribometer outcomes.

Estimating dislocation density from electron backscatter diffraction data for an AZ31/Mg-0.6Gd hybrid alloy fabricated by high-pressure torsion

ABSTRACT The Geometrically Necessary Dislocation (GND) density was estimated from Electron Backscatter Diffraction (EBSD) data for an AZ31/Mg-0.6Gd (wt.%) hybrid material fabricated by high-pressure torsion (HPT) at room temperature through an equivalent strain range of ϵeq = 0.3–144 using Kernel Average Misorientation (KAM) and the Nye tensor approaches. The results show that generally the GND densities are significant at the beginning of the deformation (ϵeq = 0.3) and decrease in both alloys when ϵeq increases. The Mg-0.6Gd alloy exhibits a lower GND density due to rapid dynamic recrystallization. These results were compared to the GND densities measured in AZ31 and Mg-0.6Gd mono-materials processed separately by HPT under the same experimental conditions. In these mono-materials the GND densities increase with increasing equivalent strain up to 7 and then decrease with further straining. The Mg-0.6Gd and AZ31 regions of the hybrid material exhibit higher GND densities than the mono-materials particularly at low strain where the disc thickness and the bonding of the AZ31/Mg-0.6Gd interfaces cause more deformation heterogeneity in the hybrid material. It is shown that the GND density evolution as a function of ϵeq has the same tendency for the KAM and the Nye approaches but the average values are significantly higher with the Nye approach. An analysis suggests that the Nye approach overestimates the GND density of the Mg-based alloys.

Observational evidence for local vertical constraining of H i by molecular cloud complexes

ABSTRACT A massive molecular cloud complex represents local gravitational potential that can constrain the vertical distribution of surrounding stars and gas. This pinching effect results in the local corrugation of the scale height of stars and gas which is in addition to the global corrugation of the mid-plane of the disc. For the first time, we report observational evidence for this pinching on the H i vertical structures in the Galactic region (20° &amp;lt; l &amp;lt; 40°), also called W41–W44 region. The H i vertical distribution is modelled by a double Gaussian profile that physically represents a narrow dense gas distribution confined to the mid-plane embedded in a wider diffuse H i. We find that the estimate of the H i scale height distribution of wider components shows corrugated structures at the locations of molecular complexes, as theoretically predicted in literature. While the narrow component is less affected by the pinching, we found a hint of the disc being disrupted by the active dynamics in the local environment of the complex, for example, supernova explosions. Molecular complexes of mass of several $10^6 \rm M_{\odot } $, associated with the mini-starburst region W43 and the supernova remnant W41 show the strongest evidence for the pinching; here a broad trough, with an average width of ∼400 pc and height ∼300 pc, in the disc thickness of the wider component is prominently visible. Searching for similar effect on the stars as well as in the location of other complexes in the Milky Way and other galaxies will be useful to establish this phenomenon more firmly.

Task-based detectability in anatomical background in digital mammography, digital breast tomosynthesis and synthetic mammography

Objective. Determining the detectability of targets for the different imaging modalities in mammography in the presence of anatomical background noise is challenging. This work proposes a method to compare the image quality and detectability of targets in digital mammography (DM), digital breast tomosynthesis (DBT) and synthetic mammography. Approach. The low-frequency structured noise produced by a water phantom with acrylic spheres was used to simulate anatomical background noise for the different types of images. A method was developed to apply the non-prewhitening observer model with eye filter (NPWE) in these conditions. A homogeneous poly(methyl) methacrylate phantom with a 0.2 mm thick aluminium disc was used to calculate 2D in-plane modulation transfer function (MTF), noise power spectrum (NPS), noise equivalent quanta, and system detective quantum efficiency for 30, 50 and 70 mm thicknesses. The in-depth MTFs of DBT volumes were determined using a thin tungsten wire. The MTF, system NPS and anatomical NPS were used in the NPWE model to calculate the threshold gold thickness of the gold discs contained in the CDMAM phantom, which was taken as reference. Main results. The correspondence between the NPWE model and the CDMAM phantom (linear Pearson correlation 0.980) yielded a threshold detectability index that was used to determine the threshold diameter of spherical microcalcifications and masses. DBT imaging improved the detection of masses, which depended mostly on the reduction of anatomical background noise. Conversely, DM images yielded the best detection of microcalcification s. Significance. The method presented in this study was able to quantify image quality and object detectability for the different imaging modalities and levels of anatomical background noise.

Nondestructive evaluation of mechanical heart valve disc thickness degradation due to accelerated durability test using THz-TDS measurements

ABSTRACT Quality assurance and control during the mechanical heart valve components’ production process is paramount to mitigate most of the valve-related complications arising from valve replacement. Nondestructive evaluation of heart valve implants with complex profiles during production is challenging due to the biocompatibility requirements and clean room assembly conditions. This study first tested the UHMWPE disc of TTK Chitra mechanical heart valve models TC1 and TC2 using Terahertz imaging in reflection mode. The UHMWPE discs were raster scanned in X-Y directions to obtain a Terahertz-C scan to locate the macro defects due to wear out, and to distinguish between the true positive and true negative samples. The results were verified with digital microscope studies. Second, this study investigates a unique relationship between Terahertz imaging in reflection mode and heart valve disc degradation due to accelerated durability study. Third, the variation of disc surface roughness due to accelerated durability test was studied by Gaussian curve fitting analysis of fast Fourier transform of the Terahertz reflections. Finally, a comparison between the TC1 and TC2 heart valve model’s wear-out foot print was carried out using Terahertz C-scan. Our results imply that Terahertz time-domain spectroscopy has promising applications in NDE measurements of biocompatible implants.

Role of galactic disc thickness in magnetic field generation

A large variety of galaxies have magnetic structures of lengthscales comparable with their radius. Theoretically, their existence is based on the dynamo mechanism. It is based on alpha-effect characterizing helicity of the turbulent motions and differential rotation which is connected with changing angular velocity. The field can be destroyed by turbulent diffusion, so the mechanism is threshold and can be realized only for the case when first and second effect are more intensive than the third one. Equations of magnetohydrodynamics that are used to describe the dynamo mechanism, are too difficult to be solved. So, usually different approximation taking into account details of astrophysical objects are used. As for galaxies, a thin disc approximation has been developed. It works properly for galactic objects with small half-thickness. However, as for thick discs we should take a model which uses more complicated structure of the field. Here we find the threshold for the field generation for thick astrophysical discs.

Evaluation of the optic disc, macula and retinal nerve fiber layer thickness in patients with thyroid associated ophthalmopathy

Evaluation of the optic disc, macula and retinal nerve fiber layer thickness in patients with thyroid associated ophthalmopathy

Morphological And Morphometric Characteristics Of The Optic Disc And Retinal Nerve Fiber Layer In Healthy Patients Evaluated By Optical Coherence Tomography At Clínica La Luz

Objective: To characterize the morphological and morphometric parameters of the optic disc and retinal nerve fiber layer (RNFL) in healthy patients studied using optical coherence tomography. Materials and Methods: Descriptive, prospective, cross-sectional study. 252 eyes of 126 patients who attended ophthalmological evaluation at Clínica La Luz in Lima, Peru, from October 2022 to July 2023 were evaluated. Using the ZEISS CIRRUS TM HD OCT Model 5000 optical coherence tomography (Carl Zeiss Inc., Dublin, CA, USA), morphological and morphometric parameters of the optic disc and RNFL thickness were measured. Megalopapilla was defined as an optic disc area &gt; 2.5mm2 and larger than the mean plus 2 standard deviations.

The Thickness of Galaxy Disks from z = 5 to 0 Probed by JWST

Although a thick disk is a structure prevalent in local disk galaxies and also present in our home Galaxy, its formation and evolution are still unclear. Whether the thick disk is born thick and/or gradually heated to be thick after formation is under debate. To disentangle these two scenarios, one effective approach is to inspect the thickness of young disk galaxies in the high-redshift Universe. In this work we study the vertical structure of 191 edge-on galaxies spanning redshift from 0.2 to 5 using JWST NIRCAM imaging observations. For each galaxy, we retrieve the vertical surface brightness profile at 1 R e and fit a sech2 function that has been convolved with the line spread function. The obtained scale height of galaxies at z > 1.5 shows no clear dependence on redshift, with a median value in remarkable agreement with that of the Milky Way’s thick disk. This suggests that local thick disks are already thick when they were formed in early times and secular heating is unlikely to be the main driver of thick disk formation. For galaxies at z < 1.5, however, the disk scale height decreases systematically toward lower redshift, with low-redshift galaxies having comparable scale height with that of the Milky Way’s thin disk. This cosmic evolution of disk thickness favors an upside-down formation scenario of galaxy disks.

Research on the nonuniform contact characteristics and thermal behavior of friction pairs involving the radial conical buckling deformation in hydro-viscous drive

An equivalent model and a finite element method was established and used for simulating the change of contact state and pressure distribution of friction pairs under the axial pressure to obtain the radial nonuniform contact characteristics and temperature field of conical friction pairs during the soft-start condition. A two-dimensional temperature field calculation model was established based on the results of contact characteristics and convective heat transfer conditions, and the transient temperature field of friction pairs during soft-start was calculated by the finite difference method. Finally, the effects of the soft-start time, deformation degree, and thickness of the steel disk were studied. The results show that the temperature and contact pressure distribution of conical deformation friction pairs exhibit local high-temperature and high-pressure areas during the soft-start process. In the early stage of soft-start, the conical friction element locally contacts in its radial central area. The contact area spreads from the center to both sides as the soft start time increases, and two contact pressure peak areas are formed near the inner and outer diameters with the increase in axial pressure. The degree of axial deformation of conical steel disk has a significant impact on contact pressure. The larger the axial deformation, the pressure distribution would be more uneven. The distribution of temperature field is significantly affected by the contact pressure. It spreads from the middle to both sides, forming high-temperature regions in the pressure peak areas. Meanwhile, the temperature on the outer side of the friction element is higher than that of the inner side due to the influence of convective heat transfer. The duration of soft start also has a significant impact on the maximum temperature and maximum temperature difference. The results could provide a theoretical basis for exploring the correlation between the thermal buckling deformation and torque instability.

In Vitro Characterizations of Poly(Ethylene Glycol) Dimethacrylate)-Nanofibrillated Cellulose as an Injectable Biomaterial Substitute for Herniated Nucleus Pulposus

Highlights: Novel synthetic biopolymer hydrogels were successfully prepared using photopolymerization method based on pristine PEGDMA and pristine NFC. Biocomposite hydrogel based on pristine PEGDMA: pristine NFC can be developed as a substitute biomaterial for the nucleus pulposus in cases of herniated nucleus pulposus which can afford for clinical application standards Abstract As many as 30-80% of cases low back pain (LBP) is frequently attributed to herniated nucleus pulposus (HNP) with 18-29% of instances reported in Indonesia. HNP can cause in motor weakness, sensory disturbances and decreased physiological reflexes. HNP occurs due to protrusion of the intervertebral disc through the annulus fibrosus which can be caused by the rupture of the annulus fibrosus or decreased proteoglycans (PGs). Hydrogel implant material is injected into the disc space, which can restore disc thickness caused by disc degeneration with minimal invasive. This study utilizes poly(ethylene glycol) dimethacrylate (PEGDMA):nanofibrillated cellulose (NFC) used to treat first-degree HNP using photopolymerization method. PEGDMA is very hydrophilic and is able to produce hydrogel. The addition of NFC to the PEGDMA precursor that forms a hydrogel was able to show mechanical properties as a hydrogel biocomposite candidate. This research to characterize of PEGDMA:NFC for biomaterial substitute of HNP. Characterizations involves Fourier Transform Infrared (FTIR) test, viscosity assessment and in vitro injection model test. PEGDMA:NFC concentrations explored include 1:0 (control), 1:0.5 (K1 sample), 1:0.75 (K2 sample) and 1:1 (K3 sample). FTIR test can indicating each functional group for hydrogel biomaterial of PEGDMA:NFC. Based on characterization results, the K3 sample has the best results with a concentration of 1:1. The viscosity value was 74,67 dPa.s and in vitro injection model test showed the addition of NFC indicates the hydrogel state when released from the mold will be not ruptured. Hydrogels can be injected with syringe 18 gauge. Consequently, the study concludes that the PEGDMA:NFC biocomposite hydrogel can be effectively applied in cases of herniated nucleus pulposus.