Preconditioned Method Research Articles

Comparative Evaluation of Micro-tensile Bond Strength in Non-carious Lesions After Different Pre-surface Treatments.

Non-carious cervical lesions (NCCLs) present themselves as smooth saucer lesions with variable height and depth. Treatment of choice for these lesions should be aimed at conservative management by restoring the teeth. The present study aims to evaluate the micro-tensile bond strength in NCCLsafter various surface pre-treatments. Sixty-six human permanent maxillary first premolars were subjected to artificial wedge-shaped lesions on the buccal aspect of the cervical regions of all the teeth. Samples were divided into two groups (n = 33 per group). Group 1 received a 37% orthophosphoric acid treatment for 30 seconds and a 17% ethylene diamine tetraacetic acid (EDTA) application for 10 seconds. Group 2 received a 10% citric acid treatment for 30 seconds, followed by a 17% EDTA application for 10 seconds. These groups were further subdivided according to the bonding agent applied as subgroup A: 3M™ Single Bond™; Subgroup B:Prime & Bond Universal group; and Subgroup C:Tetric N-Bond Universal. Samples were subjected to incremental restoration and then segmented to fit into Geraldelli jig with cyanoacrylate adhesive. A universal testing machine was used to assess the micro-tensile bond strength and the data obtained were subjected to statistical analysis. In this study, statistically significant differences in micro-tensile strength were observed between the pre-treatment groups and the effect of the bonding agent. Consequently, the null hypothesis was rejected, and the research hypothesis was accepted. The micro-tensile strength for both groups was compared with various pre-conditioning methods. It was noted that the micro-tensile strength was maximum when Tetric N Bond was used along with 37% orthophosphoric acid followed by Prime Bond with highly statistically significant values (p = 0.000). Contrary to this, in the 10% citric acid group, the micro-tensile strength was equally comparable in the 3M ESPE and Tetric N bond groups compared to the Prime Bond group, with highly statistically significant differences (p = 0.000). Surface pre-treatment in NCCLs improves the bonding strength of the restoration used. Analysis using scanning electron microscopy and long-term assessment of the failure of restoration should be carried out in future studies.

Exploring herbal preconditioning strategies to improve adipose tissue stem cell therapy efficacy

The application of mesenchymal stem cells (MSCs), specifically those sourced from adipose tissue, has become a focal point in regenerative medicine, showing potential for effective cell therapy. Adipose-derived stem cells (ASCs) offer hope in treating various conditions, yet their viability and integration rates are hindered by the harsh post-transplantation environment marked by inflammation and oxidative stress at the injury site. Lawsonia inermis (henna), Zizyphus spina-christi (Christ's Thorn), and Glycyrrhiza glabra (licorice) are three plants known for their potent antioxidant properties primarily due to their rich content of phenolic compounds and flavonoids. Their potential health benefits make them valuable in both traditional medicine and modern therapeutic applications.This research delves into investigating and contrasting the effects of hydroalcoholic extracts from Lawsonia inermis, Zizyphus spina-christi, and Glycyrrhiza glabra on human adipose tissue stem cells as a pre-conditioning method to alleviate oxidative stress in cell therapy. ASCs were isolated from the pelvic cavity and abdomen, characterized using flow cytometry, and prompted to differentiate into adipogenic and osteogenic lineages. They were then subjected to different concentrations of the aforementioned herbal extracts at varying time frames, followed by MIC and MTT analysis. The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay and the Minimum Inhibitory Concentration (MIC) assay are both used to evaluate the effects of substances on cell viability and cell growth receptively. RNA extraction from ASCs and evaluation of antioxidant gene expression were conducted via Real-time PCR. Flow cytometry data confirmed the presence of MSC markers in the isolated cells from ASCs. Analysis of the herbal extract concentrations revealed that 50 ng/ml had a toxic effect on ASCs, establishing a toxicity reference point for adipose-derived MSCs. Real-time PCR results showcased a notable increase in the expression of antioxidant genes post-preconditioning with hydroalcoholic extracts. This study underscores, for the first time, the safety and lack of toxicity of preconditioning with these extracts for h.ASCs, enhancing their resilience and acclimatization under oxidative stress conditions, potentially boosting the therapeutic potential of h.ASCs. The antioxidant properties of Lawsonia inermis, Zizyphus spina-christi, and Glycyrrhiza glabra may enhance the expression of antioxidant genes (Sod, Gpx and Cata) through several mechanisms, including the activation of transcription factors like Nrf2 (Nuclear factor erythroid 2-related factor 2), which regulates antioxidant gene expression; modulation of signaling pathways such as MAPK (Mitogen-Activated Protein Kinase) and PI3K/Akt (Phosphoinositide 3-kinase/Protein Kinase B); and influencing epigenetic modifications like histone changes or DNA methylation that can alter gene expression. However, further research is necessary to clarify the specific mechanisms by which these plant extracts enhance antioxidant gene expression and to explore their potential therapeutic applications in combating oxidative stress-related diseases. Future proposals should consider more gene investigation and in vivo applications, as well as the long-term effects of pre-conditioning.

A new preconditioned Gauss-Seidel method for solving $${\mathcal {M}}$$-tensor multi-linear system

A new preconditioned Gauss-Seidel method for solving $${\mathcal {M}}$$-tensor multi-linear system

A matrix-free parallel two-level deflation preconditioner for two-dimensional heterogeneous Helmholtz problems

We propose a matrix-free parallel two-level deflation method combined with the Complex Shifted Laplacian Preconditioner (CSLP) for two-dimensional heterogeneous Helmholtz problems encountered in seismic exploration, antennas, and medical imaging. These problems pose challenges in terms of accuracy and convergence due to scalability issues with numerical solvers. Motivated by the limitations imposed by excessive computational time and memory constraints when employing a sequential solver with constructed matrices, we parallelize the two-level deflation method without constructing any matrices. Our approach utilizes preconditioned Krylov subspace methods and approximates the CSLP preconditioner with a parallel geometric multigrid V-cycle. For the two-level deflation, standard inter-grid deflation vectors and further high-order deflation vectors are considered. As another main contribution, the matrix-free Galerkin coarsening approach and a novel re-discretization scheme as well as high-order finite-difference schemes on the coarse grid are studied to obtain wavenumber-independent convergence. The optimal settings for an efficient coarse-grid problem solver are investigated. Numerical experiments of model problems show that the wavenumber independence has been obtained for medium wavenumbers. The matrix-free parallel framework shows satisfactory weak and strong parallel scalability.

Dual Domain Decomposition Method for High-Resolution 3D Simulation of Groundwater Flow and Transport

The high-resolution 3D groundwater flow and transport simulation problem requires massive discrete linear systems to be solved, leading to significant computational time and memory requirements. The domain decomposition method is a promising technique that facilitates the parallelization of problems with minimal communication overhead by dividing the computation domain into multiple subdomains. However, directly utilizing a domain decomposition scheme to solve massive linear systems becomes impractical due to the bottleneck in algebraic operations required to coordinate the results of subdomains. In this paper, we propose a two-level domain decomposition method, named dual-domain decomposition, to efficiently solve the massive discrete linear systems in high-resolution 3D groundwater simulations. The first level of domain decomposition partitions the linear system problem into independent linear sub-problems across multiple subdomains, enabling parallel solutions with significantly reduced complexity. The second level introduces a domain decomposition preconditioner to solve the linear system, known as the Schur system, used to coordinate results from subdomains across their boundaries. This additional level of decomposition parallelizes the preconditioning of the Schur system, addressing the bottleneck of the Schur system solution while improving its convergence rates. The dual-domain decomposition method facilitates the partition and distribution of the computation to be solved into independent finely grained computational subdomains, substantially reducing both computational and memory complexity. We demonstrate the scalability of our proposed method through its application to a high-resolution 3D simulation of chromium contaminant transport in groundwater. Our results indicate that our method outperforms both the vanilla domain decomposition method and the algebraic multigrid preconditioned method in terms of runtime, achieving up to 8.617× and 5.515× speedups, respectively, in solving massive problems with approximately 108 million degrees of freedom. Therefore, we recommend its effectiveness and reliability for high-resolution 3D simulations of groundwater flow and transport.

3D printing of interferon γ-preconditioned NSC-derived exosomes/collagen/chitosan biological scaffolds for neurological recovery after TBI

The reconstruction of neural function and recovery of chronic damage following traumatic brain injury (TBI) remain significant clinical challenges. Exosomes derived from neural stem cells (NSCs) offer various benefits in TBI treatment. Numerous studies confirmed that appropriate preconditioning methods enhanced the targeted efficacy of exosome therapy. Interferon-gamma (IFN-γ) possesses immunomodulatory capabilities and is widely involved in neurological disorders. In this study, IFN-γ was employed for preconditioning NSCs to enhance the efficacy of exosome (IFN-Exo, IE) for TBI. miRNA sequencing revealed the potential of IFN-Exo in promoting neural differentiation and modulating inflammatory responses. Through low-temperature 3D printing, IFN-Exo was combined with collagen/chitosan (3D-CC-IE) to preserve the biological activity of the exosome. The delivery of exosomes via biomaterial scaffolds benefited the retention and therapeutic potential of exosomes, ensuring that they could exert long-term effects at the injury site. The 3D-CC-IE scaffold exhibited excellent biocompatibility and mechanical properties. Subsequently, 3D-CC-IE scaffold significantly improved impaired motor and cognitive functions after TBI in rat. Histological results showed that 3D-CC-IE scaffold markedly facilitated the reconstruction of damaged neural tissue and promoted endogenous neurogenesis. Further mechanistic validation suggested that IFN-Exo alleviated neuroinflammation by modulating the MAPK/mTOR signaling pathway. In summary, the results of this study indicated that 3D-CC-IE scaffold engaged in long-term pathophysiological processes, fostering neural function recovery after TBI, offering a promising regenerative therapy avenue.

Effect of concrete preconditioning method on accelerated carbonation rate

Several methods have been proposed for the accelerated carbonation test of concrete, but there is no consensus on the best procedure for preconditioning the specimens. Thus, this study aims to assess the effects of four preconditioning methods - ISO 1920-12:2015, EN 13295:2004, XP P 18-458:2008 and RILEM TC 116-PDC:1999 - on the accelerated carbonation test. Four different concrete mixtures were used to ensure variations in mechanical strength and porosity. The specimens were subjected to accelerated carbonation in a chamber with 3% CO2, 65% RH and 23 °C for 14, 28 and 42 days, so that a database of 1536 carbonation measurements was produced. Internal and surface moisture of the concrete were measured at various stages throughout the experiment. Statistical analysis revealed that the preconditioning method significantly impacted the concrete’s carbonation rate - Fcalc (126.68) ≫ Ftab (2.61), with p-value ≅ 0. Preconditioning affected the concrete’s moisture content at the beginning of the process, and inverse linear relationships were found between concrete surface moisture and carbonation depth (0.85 ≤ R2 ≤ 0.99). The study points to the usefulness of the surface moisture technique to monitor specimens during carbonation tests, and it concluded that XP was the best among the four methods studied.

Quantification and cultivation of Helicobacter pylori (H. pylori) from various urban water environments: A comprehensive analysis of precondition methods and sample characteristics

Substantial evidence suggests that all types of water, such as drinking water, wastewater, surface water, and groundwater, can be potential sources of Helicobacter pylori (H. pylori) infection. Thus, it is critical to thoroughly investigate all possible preconditioning methods to enhance the recovery of H. pylori, improve the reproducibility of subsequent detection, and optimize the suitability for various water types and different detection purposes. In this study, we proposed and evaluated five distinct preconditioning methods for treating water samples collected from multiple urban water environments, aiming to maximize the quantitative qPCR readouts and achieve effective selective cultivation. According to the experimental results, when using the qPCR technique to examine WWTP influent, effluent, septic tank, and wetland water samples, the significance of having a preliminary cleaning step becomes more evident as it can profoundly influence qPCR detection results. In contrast, the simple, straightforward membrane filtration method could perform best when isolating and culturing H. pylori from all water samples. Upon examining the cultivation and qPCR results obtained from groundwater samples, the presence of infectious H. pylori (potentially other pathogens) in aquifers must represent a pressing environmental emergency demanding immediate attention. Furthermore, we believe groundwater can be used as a medium to reflect the H. pylori prevalence in a highly populated community due to its straightforward analytical matrix, consistent detection performance, and minimal interferences from human activities, temperature, precipitation, and other environmental fluctuations.

Surface coating method for cement-based materials to improve chloride ion penetration resistance using amine-based CO2 solvent

The application of coatings on concrete surfaces serves as a protective shield, guarding the structure against chlorides and averting corrosion of the reinforcement, consequently enhancing its durability. This study investigates the resistance of cement mortar samples to chloride ion penetration when coated with an amine-based carbon dioxide (CO2) solvent. Various factors, including monoethanolamine (MEA) concentrations of 1, 10, and 30 wt%; water-to-cement ratios (w/cm) of 0.35, 0.4, and 0.5; coating timings on day 3 and day 27; and pre-conditioning methods such as air drying, are investigated for their impact on the performance of chloride penetration resistance. Specifically, pre-conditioning significantly enhanced the performance of the coatings, especially in samples with a higher w/cm. Coatings applied at an early stage demonstrated superior resistance to chloride ion penetration compared to those applied later in the curing process. Moreover, solutions with higher concentrations of MEA, capturing more CO2, encouraged the resistance against chloride penetration by reducing capillary macropores within the cement mortar samples. Diffusivity analysis of the coated surface layer confirmed the efficacy of the CO2-dissolved MEA solution as a barrier against chloride ion penetration. Optimal performance was possibly observed in the samples produced by a w/cm of 0.4 and their treatment with more than 10% MEA concentrations.

A split preconditioning scheme for nonlinear underdetermined least squares problems

AbstractThe convergence of preconditioned gradient methods for nonlinear underdetermined least squares problems arising in, for example, supervised learning of overparameterized neural networks is investigated. In this general setting, conditions are given that guarantee the existence of global minimizers that correspond to zero residuals and a proof of the convergence of a gradient method to these global minima is presented. In order to accelerate convergence of the gradient method, different preconditioning strategies are developed and analyzed. In particular, a left randomized preconditioner and a right coarse‐level correction preconditioner are combined and investigated. It is demonstrated that the resulting split preconditioned two‐level gradient method incorporates the advantages of both approaches and performs very efficiently.

Approximate inner solvers for block preconditioning of the incompressible Navier–Stokes problems discretized by isogeometric analysis

AbstractWe deal with efficient numerical solution of the steady incompressible Navier–Stokes equations (NSE) using our in‐house solver based on the isogeometric analysis (IgA) approach. We are interested in the solution of the arising saddle‐point linear systems using preconditioned Krylov subspace methods. Based on our comparison of ideal versions of several state‐of‐the‐art block preconditioners for linear systems arising from the IgA discretization of the incompressible NSE, suitable candidates have been selected. In the present paper, we focus on selecting efficient approximate solvers for solving subsystems within these preconditioning methods. We investigate the impact on the convergence of the outer solver and aim to identify an effective combination. For this purpose, we compare convergence properties of the selected solution approaches for problems with different viscosity values, mesh refinement levels and discretization bases.

Auxiliary splines space preconditioning for B-splines finite elements: The case of [formula omitted] and [formula omitted] elliptic problems

This paper presents a study of large linear systems resulting from the regular B-splines finite element discretization of the curl−curl and grad−div elliptic problems on unit square/cube domains. We consider systems subject to both homogeneous essential and natural boundary conditions. Our objective is to develop a preconditioning strategy that is optimal and robust, based on the Auxiliary Space Preconditioning method proposed by Hiptmair et al. [48]. Our approach is demonstrated to be robust with respect to mesh size, and we also show how it can be combined with the Generalized Locally Toeplitz (GLT) sequences analysis presented in [59] in order to derive an algorithm that is optimal and stable with respect to spline degree. Numerical tests are conducted to illustrate the effectiveness of our approach.

Ultrasonic aerosol agglomeration: Manipulation of particle deposition and its impact on air filter pressure drop

Acoustic agglomeration is a technique that leverages on sound waves to promote the collision of aerosol particulate matter, thus leading to the formation of larger particle agglomerates. In this study, this acoustics-driven phenomenon is demonstrated for its usefulness as an aerosol pre-conditioning method to significantly enhance the efficiency of filtration systems in particle treatment processes. Specifically, favorable changes in pressure drop across the filters are observed as a result of receiving less particle mass, for which filters are shown to be able to have their operational life extended remarkably by more than 50%. The involved ultrasonic aerosol agglomeration mechanisms are unveiled through numerical simulations, and the effects of residence time, sound pressure level, and initial particle number concentration on agglomeration performances are experimentally investigated. In addition, validations and measurements of filter pressure drop are obtained through a series of experiments. This study provides a comprehensive overview to the design and performance characterization of acoustics-agglomeration-enhanced filtration systems, which could potentially derive energy savings for fan power in ventilation systems and be scaled up for applications in industrial plants for reducing carbon emissions.

Two-parameter modified matrix splitting iteration method for Helmholtz equation

For effectively solving the nonsymmetric and indefinite linear system originating from the discretized Helmholtz equation with complex wavenumber, we propose a two-parameter modified matrix splitting iteration method. We establish the asymptotic convergence theory for this method and demonstrate its convergence under certain conditions. The proposed iteration method leads to a new preconditioner that can be efficiently inverted by using the discrete sine transform. Numerical experiments are carried out to show that the new preconditioner significantly improves the convergence rate of the GMRES method, which results in effective preconditioned GMRES method for solving the Helmholtz equation of high wavenumber.

Allo Beta Cell transplantation: specific features, unanswered questions, and immunological challenge.

Type 1 diabetes (T1D) presents a persistent medical challenge, demanding innovative strategies for sustained glycemic control and enhanced patient well-being. Beta cells are specialized cells in the pancreas that produce insulin, a hormone that regulates blood sugar levels. When beta cells are damaged or destroyed, insulin production decreases, which leads to T1D. Allo Beta Cell Transplantation has emerged as a promising therapeutic avenue, with the goal of reinstating glucose regulation and insulin production in T1D patients. However, the path to success in this approach is fraught with complex immunological hurdles that demand rigorous exploration and resolution for enduring therapeutic efficacy. This exploration focuses on the distinct immunological characteristics inherent to Allo Beta Cell Transplantation. An understanding of these unique challenges is pivotal for the development of effective therapeutic interventions. The critical role of glucose regulation and insulin in immune activation is emphasized, with an emphasis on the intricate interplay between beta cells and immune cells. The transplantation site, particularly the liver, is examined in depth, highlighting its relevance in the context of complex immunological issues. Scrutiny extends to recipient and donor matching, including the utilization of multiple islet donors, while also considering the potential risk of autoimmune recurrence. Moreover, unanswered questions and persistent gaps in knowledge within the field are identified. These include the absence of robust evidence supporting immunosuppression treatments, the need for reliable methods to assess rejection and treatment protocols, the lack of validated biomarkers for monitoring beta cell loss, and the imperative need for improved beta cell imaging techniques. In addition, attention is drawn to emerging directions and transformative strategies in the field. This encompasses alternative immunosuppressive regimens and calcineurin-free immunoprotocols, as well as a reevaluation of induction therapy and recipient preconditioning methods. Innovative approaches targeting autoimmune recurrence, such as CAR Tregs and TCR Tregs, are explored, along with the potential of stem stealth cells, tissue engineering, and encapsulation to overcome the risk of graft rejection. In summary, this review provides a comprehensive overview of the inherent immunological obstacles associated with Allo Beta Cell Transplantation. It offers valuable insights into emerging strategies and directions that hold great promise for advancing the field and ultimately improving outcomes for individuals living with diabetes.

THE EFFECTS OF VARIOUS MODES OF INTERVAL HYPOXIC TRAINING IN EXPERIMENTAL MODELS OF ANXIETY AND DEPRESSION IN RATS

The development of non-drug methods for correcting stress-induced disorders and improving adaptation to stressful factors remains an urgent task of physiology, which has a great translational potential. Previously, we proposed effective methods of hypoxic hypobaric preconditioning and distant ischemic conditioning in this regard. The purpose of this work was to transfer the principles of preconditioning to the approaches of normobaric intermittent hypoxic training (IHT). The effects of five new IHT regimens (3 five-minute sessions of hypoxia of 16% O2 per day, 3 sessions of 12% O2, 7 sessions of 12% O2, 15 sessions of 12% O2, 3 sessions of 9% O2) were studied in experimental models of depression and post-traumatic stress disorder in rats. The preconditioning regime of high intensity 3x9%O2 had the most pronounced antidepressant and anxiolytic effect in models of both pathologies. With a decrease in the level of hypoxia to 12% O2, IHT regimens partially retained their effectiveness with an increase in the number of sessions. The training regime of the longest duration – 15 × 12%O2, was effective in correcting the formation of experimental depression. The intermediate regime – 7 × 12%O2, had an anxiolytic effect, while the preconditioning regime of medium intensity – 3 × 12%O2, demonstrated both an antidepressant and anxiolytic effect. The results indicate that the intensity of hypoxic exposure had the greatest impact on the effectiveness. At the same time, a decrease in the intensity to 16% O2 led to a weakening or loss of stress-protective properties. With regard to the 3 × 9%O2 regime as the most promising, it is advisable to conduct further studies to identify the molecular mechanisms that implement its stress-protective and anxiolytic effects.

Preconditioners based on matrix splitting for the structured systems from elliptic PDE-constrained optimization problems

With regard to the structured systems of linear equations, which arises from the Galerkin finite element discretizations of elliptic PDE-constrained optimization problems, some new preconditioners based on coefficient matrix splitting are established to speed up the convergence rate of Krylov subspace methods such as GMRES. Additionally, eigenvalue distribution of the corresponding preconditioned matrices is deeply discussed. Numerical simulations are carried out, the results of which exhibit that the corresponding preconditioned GMRES methods perform very well with the theoretical analysis results and are superior to other newly devised preconditioners.

Fractional-order iterative learning control for fractional-order systems with initialization non-repeatability

The effect of initialization non-repeatability on iterative learning control performance for fractional-order systems has not been sufficiently investigated. It is a hidden deficiency that leads directly to the breaking of perfect tracking conditions in both theoretical analysis and real-world applications. Therefore, under the framework of general fractional-order nonlinear systems, this paper proposes an open-close loop Dα-type iterative learning control scheme based on system preconditioning and strictly derives two convergence conditions. By applying the preconditioning optimization strategy based on the short-memory principle, the tracking error due to initialization nonrepetition can converge to any desired range. Compared with the existing results, the proposed iteration scheme fully considers the complexity of the initialization and initial conditions of fractional-order systems, and provides several practical preconditioning methods to improve the tracking efficiency. Two numerical examples are presented to validate the above conclusions.

Features of the use of ischemic preconditioning for the correction of vibration polyneuropathy of the upper extremities

Introduction. The study of the methods for non-pharmacological correction of vibration polyneuropathy is relevant in view of the high prevalence of vibration disease in various industries, and high occurrence of disability of workers. Ischemic preconditioning has shown its effectiveness in correcting the manifestations of vibration polyneuropathies. The high frequency of nerve compression in tunnels against the background of polyneuropathic lesions in vibration disease dictates the need to study the effectiveness of the method in various forms of vibration polyneuropathy.
 The aim of the study was to investigate the effectiveness of ischemic preconditioning in various forms of vibration polyneuropathy.
 Materials and methods. Twenty nine patients with a proven diagnosis of vibration disease were examined and treated uisng the ischemic preconditioning. They were divided into 2 groups: group 1 – 18 individuals with upper extremities polyneuropathy without nerve compression, group 2 – 11 subjects with compression complications of polyneuropathy. The examinations included neurological survey, electroneuromyographic investigation before and after the course of ischemic preconditioning conducted according to a patented technique.
 Results. A decrease in sensory disturbances and improvement in the impulse conduction along the sensory fibers of the nerves of the upper extremities after a course of ischemic preconditioning in the group of the patients without compression neuropathies were noted. In the group of the patients with polyneuropathies complicated by the nerve compression in tunnels, the positive effect was less significant.
 Limitations. The study was limited by the assessment of clinical and electroneuromyographic parameters in 29 patients with vibration disease due to the exposure to local vibration before and after the course of ischemic preconditioning.
 Conclusion. The method of ischemic preconditioning is effective as a method for non-pharmacological correction of vibration polyneuropathy. Compression neuropathies are predictors of lower efficiency of the method, and therefore it is important to select patients for the treatment by this method with the preferred inclusion of the patients with uncomplicated vibration polyneuropathies.

Development of an efficient calculation technique for dynamics of mooring lines by using discrete forms of rotation

Development of efficient calculation techniques is of key importance for design of deepwater moored floating structures consisting of many subsystems, such as a floating vessel, risers and mooring lines. In particular, this study focuses on a method for simulating dynamic behavior of the mooring line, since it includes a lot of degrees of freedom and geometric nonlinear effects. A modified Morison equation based on the linear potential flow theory is employed to derive the hydrodynamic forces acting on the lines. The present approach describes the mooring lines (chain) as multi-rigid bodies based on the multibody dynamics approach. In addition, a discrete form of rotation called “the rotation update equation” is introduced. This technique approximates the rotation by using incremental components of rotation in terms of the angular velocity. This approach can bypass the parameterization of rotation in the equations of motion. Clearly, it contributes to reduction of computational costs. Furthermore, a preconditioning method is applied to the equations of motions in order to prevent the ill-conditioning which affects convergence of the numerical integration procedures for the set of equations with configuration level constraints. Finally, a comparison of results by the present method and the conventional method are presented in order to show the validity of the method.