bluuebunny/crossref_metadata_2025 huggingface dataset:
The use of acupuncture in radiation-induced complications among cancer patients
Authors:   University Of Johannesburg, Joubert Kelley Sue
Published: February 2024

Background: Radiation-induced complications commonly occur among patients who receive radiation therapy. Various research reports that acupuncture treatment significantly reduces radiation-induced complications experienced by patients undergoing radiation therapy. However, there is a lack of review on the use of acupuncture in the treatment of radiation-induced complications among cancer patients. Aim: The aim of this study was to conduct a narrative review on the use of acupuncture in the treatment of radiation-induced complications among cancer patients. Methodology: A narrative review was conducted using extensive databases including PubMed, EBSCO host, and Science Direct. Studies included in this review had to meet inclusion criteria based on the date of publication and relevance to acupuncture in treatment for radiation-induced complications. A total of 16 studies met the inclusion criteria for this narrative review on the radiation-induced side-effects, which included mucositis (n= 3), stomatitis (n= 1), xerostomia (n= 6), nausea and emesis (n= 3), and dysphagia (n=3), treated with acupuncture. Results: Studies observing acupuncture in the treatment of stomatitis, mucositis and xerostomia all showed positive results with significant improvement experienced in patients treated with acupuncture compared to those treated with sham-acupuncture and control groups, with one study for mucositis using a combined therapy of acupuncture and cooling herbs. Studies included for nausea and emesis demonstrated mixed results of no improvement (n= 2) and improvement (n= 1). Conclusion: Acupuncture demonstrates a significant ability to reduce the severity of common radiation-induced complications caused by radiation therapy among some cancer patients. This study was limited to the small sample size due to the limited research on this topic. More studies on the use of acupuncture treatment to reduce radiation-induced complications among other cancer patients are recommended to strengthen the evidence.
Altered hierarchical auditory predictive processing after lesions to the orbitofrontal cortex
Authors: Asko Olgerta , Blenkmann Alejandro Omar , Leske Sabine Liliana , Foldal Maja Dyhre , LLorens Anais , Funderud Ingrid , Meling Torstein R , Knight Robert T , Endestad Tor , Solbakk Anne-Kristin
Published: February 2024

Orbitofrontal cortex (OFC) is classically linked to inhibitory control, emotion regulation, and reward processing. Recent perspectives propose that the OFC also generates predictions about perceptual events, actions, and their outcomes. We tested the role of the OFC in detecting violations of prediction at two levels of abstraction (i.e., hierarchical predictive processing) by studying the event-related potentials (ERPs) of patients with focal OFC lesions (n = 12) and healthy controls (n = 14) while they detected deviant sequences of tones in a local–global paradigm. The structural regularities of the tones were controlled at two hierarchical levels by rules defined at a local (i.e., between tones within sequences) and at a global (i.e., between sequences) level. In OFC patients, ERPs elicited by standard tones were unaffected at both local and global levels compared to controls. However, patients showed an attenuated mismatch negativity (MMN) and P3a to local prediction violation, as well as a diminished MMN followed by a delayed P3a to the combined local and global level prediction violation. The subsequent P3b component to conditions involving violations of prediction at the level of global rules was preserved in the OFC group. Comparable effects were absent in patients with lesions restricted to the lateral PFC, which lends a degree of anatomical specificity to the altered predictive processing resulting from OFC lesion. Overall, the altered magnitudes and time courses of MMN/P3a responses after lesions to the OFC indicate that the neural correlates of detection of auditory regularity violation are impacted at two hierarchical levels of rule abstraction.
Species and habitat specific changes in bird activity in an urban environment during Covid 19 lockdown
Authors: Sun Congnan , Hassin Yoel , Boonman Arjan , Shwartz Assaf , Yovel Yossi
Published: February 2024

Covid-19 lockdowns provided ecologists with a rare opportunity to examine how animals behave when humans are absent. Indeed many studies reported various effects of lockdowns on animal activity, especially in urban areas and other human-dominated habitats. We explored how Covid-19 lockdowns in Israel have influenced bird activity in an urban environment by using continuous acoustic recordings to monitor three common bird species that differ in their level of adaptation to the urban ecosystem: (1) the hooded crow, an urban exploiter, which depends heavily on anthropogenic resources; (2) the rose-ringed parakeet, an invasive alien species that has adapted to exploit human resources; and (3) the graceful prinia, an urban adapter, which is relatively shy of humans and can be found in urban habitats with shrubs and prairies. Acoustic recordings provided continuous monitoring of bird activity without an effect of the observer on the animal. We performed dense sampling of a 1.3 square km area in northern Tel-Aviv by placing 17 recorders for more than a month in different micro-habitats within this region including roads, residential areas and urban parks. We monitored both lockdown and no-lockdown periods. We portray a complex dynamic system where the activity of specific bird species depended on many environmental parameters and decreases or increases in a habitat-dependent manner during lockdown. Specifically, urban exploiter species decreased their activity in most urban habitats during lockdown, while human adapter species increased their activity during lockdown especially in parks where humans were absent. Our results also demonstrate the value of different habitats within urban environments for animal activity, specifically highlighting the importance of urban parks. These species- and habitat-specific changes in activity might explain the contradicting results reported by others who have not performed a habitat specific analysis.
A computational model predicts sex-specific responses to calcium channel blockers in mammalian mesenteric vascular smooth muscle
Authors: Hernandez-Hernandez Gonzalo , O'Dwyer Samantha C , Yang Pei-Chi , Matsumoto Collin , Tieu Mindy , Fong Zhihui , Lewis Timothy J , Santana L Fernando , Clancy Colleen E
Published: February 2024

The function of the smooth muscle cells lining the walls of mammalian systemic arteries and arterioles is to regulate the diameter of the vessels to control blood flow and blood pressure. Here, we describe an in silico model, which we call the ‘Hernandez–Hernandez model’, of electrical and Ca2+ signaling in arterial myocytes based on new experimental data indicating sex-specific differences in male and female arterial myocytes from murine resistance arteries. The model suggests the fundamental ionic mechanisms underlying membrane potential and intracellular Ca2+ signaling during the development of myogenic tone in arterial blood vessels. Although experimental data suggest that KV1.5 channel currents have similar amplitudes, kinetics, and voltage dependencies in male and female myocytes, simulations suggest that the KV1.5 current is the dominant current regulating membrane potential in male myocytes. In female cells, which have larger KV2.1 channel expression and longer time constants for activation than male myocytes, predictions from simulated female myocytes suggest that KV2.1 plays a primary role in the control of membrane potential. Over the physiological range of membrane potentials, the gating of a small number of voltage-gated K+ channels and L-type Ca2+ channels are predicted to drive sex-specific differences in intracellular Ca2+ and excitability. We also show that in an idealized computational model of a vessel, female arterial smooth muscle exhibits heightened sensitivity to commonly used Ca2+ channel blockers compared to male. In summary, we present a new model framework to investigate the potential sex-specific impact of antihypertensive drugs.
A study of the interactive mediating effect of ADHD and NSSI caused by co-disease mechanisms in males and females
Authors: Cheng Fang , Shi Linwei , Xie Huabing , Wang Beini , Hu Changzhou , Zhang Wenwu , Hu Zhenyu , Yu Haihang , Wang Yiming
Published: February 2024

Background

Non-suicidal self-injury (NSSI), of which the predisposing factors are complex and diverse, profoundly affects the physical and mental health of young people. Therefore, this work established an NSSI intermediary network model considering the interaction of multiple factors. A mediating effect between attention-deficit/hyperactivity disorder (ADHD) and NSSI, considering the influence of comorbidities, such as depression, anxiety, and impulsive personality, was proposed based on sex differences.

Methods

A total of 2,689 middle school students in Ningbo City, Zhejiang Province, China, were randomly sampled and participated in this study. Data regarding their demographic characteristics, attention deficit, hyperactivity/impulsivity, NSSI, anxiety, depression, internet addiction, and other comorbid symptoms were collected and analyzed. After initially screening the data, variables were assessed for significance using a single-factor inter-group difference analytic method, and a binary logistic regression analysis was performed. The intermediary effect of factors influencing NSSI in males and females was also analyzed.

Results

The overall NSSI rate was 15.16%. The results showed that the impact of individual impulsivity characteristics (impulsiveness, the ADHD with hyperactivity/impulsivity subtype) on NSSI behavior was not significant (regression results, P > 0.05). The degree of association between ADHD with attention deficit and ADHD with comprehension deficit subtypes, and other comorbid symptoms (depression, anxiety, and internet addiction disorder) and NSSI, with odds ratios (ORs) of 7.6/6.42/436.68/3.82/1.86, and 95% bootstrap confidence intervals (CIs) of 4.64, 12.87/3.46, 12.67/137.42, 2659.13/2.32, 6.37/1.31, 2.82, respectively. The results also showed significant effects of ADHD subtypes on comorbid symptoms and the path effects of NSSI (P < 0.01). Among them, the mediating effect was the strongest when anxiety was the mediating variable, and the mediating effect of girls was higher than that of boys.

Conclusion

The results of this work demonstrated the influence of ADHD symptoms on NSSI behavior. Among patients with ADHD, patients with subtypes with obvious attention deficit characteristics were more likely to exhibit NSSI behavior, whereas the hyperactive impulse subtype had no direct impact on NSSI. We conclude that adolescent impulsivity may not be directly related to NSSI behavior and that impulsive characteristics jointly affect NSSI behavior through a series of NSSI comorbid symptoms. Notably, the probability of symptom onset and the degree of comorbidity was significantly higher in girls than in boys of the same age, and girls were more prone to NSSI behavior. These findings provide effective theoretical support for the prevention and treatment of adolescent NSSI behavior.
Commonly Used Tests in the Assessment of Sacro-illiac Joint Dysfunction by Physiotherapists in India: A Cross-sectional Study
Authors: Philip Aleena , Srivastava Saumya
Published: February 2024

Introduction: Sacroiliac Joint Dysfunction (SIJD) refers to a condition that causes pain and discomfort, commonly due to dysfunction of the Sacroiliac Joint (SIJ). It is a plausible source of Low Back Pain (LBP). Static palpation tests, motion palpation, and pain provocation tests are mostly employed to check for SIJD. Aim: To determine the commonly used tests in the assessment of SIJD by physiotherapists. Materials and Methods: A cross-sectional Questionnairebased study was conducted among physiotherapists in India from November 2022 to April 2023 at the Nitte Institute of Physiotherapy, NITTE (deemed to be University), Mangalore, Karnataka, India. The study included physiotherapists specialising in orthopaedics and obstetrics and gynaecology. The practitioners’ years of experience were considered. An online survey was conducted using a questionnaire developed to determine the frequently used bony landmark for checking SIJ asymmetry, commonly affected structures, and commonly used motion palpation and pain provocation tests for examining SIJD. Questionnaires were sent to at least 100 physiotherapists, and 72 responses were included in the study. Data was collected and analysed using descriptive statistics: frequency and percentage. Data analysis was performed using Statistical Package for Social Sciences (SPSS) software version 26.0. Results: Seventy-two practitioners responded to the online survey. The commonly assessed bony landmark was the Posterior Superior Iliac Spines (PSIS) with 52 responses (28%). The most frequently preferred motion palpation examination test was the compression test with 36 responses (17.2%). Tenderness or tissue texture change was mainly checked at the PSIS with 54 responses (37.8%), and the commonly used pain provocation tests were the thigh thrust test and supine SIJ springing test with 46 responses (26.6%). Conclusion: According to this study, many physiotherapists employed diagnostic techniques congruent with Mitchell’s model, but they also frequently added additional motion tests, measured tenderness, and used pain provocation techniques. Most preferred the ASIS compression and thigh thrust tests to assess SIJD.
Pathogenicity and Antibiotic Resistance of Pseudomonas aeruginosa: A Comprehensive Review
Authors: Ahmad Nadeem , Siddiqui Areena Hoda , Sharma Meenakshi , Arya Amita
Published: February 2024

Pseudomonas aeruginosa (P. aeruginosa) presents a complex challenge in terms of pathogenicity and antibiotic resistance. This versatile pathogen adeptly colonises various host tissues and evades the immune system through its intricate virulence factors. The review delves into the antimicrobial resistance mechanisms at play, which encompass inherent resistance characteristics and those acquired through genetic mutations and horizontal gene transfer. Notably, efflux pump systems and limited membrane permeability underpin its inherent resistance, rendering many conventional antibiotics ineffective. Multidrug Resistant (MDR) strains are on the rise, posing a substantial threat to patient care and infection control. In response, innovative strategies are being explored, including combination therapies to enhance the effectiveness of existing antibiotics and drug repurposing, redirecting existing medications to target P. aeruginosa. Phage therapy, which leverages bacteriophages to combat P. aeruginosa infections, is gaining attention as a promising solution. Infection prevention and control are pivotal, particularly in healthcare settings, to curtail the spread of P. aeruginosa. Surveillance programs are crucial for monitoring the prevalence and dissemination of antibiotic-resistant strains and guiding response strategies during outbreaks. Comprehending P. aeruginosa’s complex virulence and resistance mechanisms is paramount for developing efficient treatments and effective infection control measures. Ongoing research and collaborative efforts are instrumental in mitigating the substantial impact of P. aeruginosa infections on public health, underscoring the need for sustained vigilance and innovation in infectious disease management.
Histopathological Spectrum of Ovarian Tumours in a Tertiary Care Centre in South Kerala, India: A Cross-sectional Study
Authors: Das PH Anitha , Praseeda I , Sadanandan Anjali
Published: February 2024

Introduction: Ovarian tumours are among the most common tumours in females, exhibiting diverse histopathological patterns that remain crucial for early diagnosis. Proper classification of ovarian neoplasms, particularly malignant ones, is essential for accurate treatment. Accurately subclassifying ovarian tumours aids in treatments such as targeted therapy. Aim: To examine the histopathological spectrum of ovarian tumours and to assess the role of histopathology in accurate diagnosis and treatment. Materials and Methods: A cross-sectional study on the histopathological spectrum of ovarian tumours was conducted in Department of Pathology, Travancore Medical College, Kollam, Kerala, India, over a five-year period (January 2017 to December 2021). The study included 850 ovarian specimens, and the various histopathological patterns were studied according to the World Health Organisation (WHO) classification of ovarian tumours, 5th edition, 2020. These patterns and age distribution were expressed in frequency and percentage. Results: Out of the 850 ovarian specimens, 140 were neoplastic and 710 were non neoplastic. Abdominal pain was the most common clinical presentation (30%). Among the 140 neoplastic cases, 115 were benign, 20 were malignant, and five were borderline. The majority of cases, including benign, borderline, and malignant tumours, were seen in the age group of 31-40 years (25.71%). Benign tumours were more common than malignant ones in all age groups. Categorising based on histopathological patterns, epithelial tumours were the most common (88 cases, 62.86%). Serous cystadenoma was the most common benign tumour, constituting 36 out of 115 benign cases (25.71%). Borderline serous tumour was the most common borderline epithelial tumour (3 out of total 5 borderline ovarian neoplasms, 2.14%). Serous cystadenocarcinoma was the most common malignant tumour (5 cases, 03.57%). Conclusion: The wide spectrum of ovarian tumours presents diagnostic challenges. Effective therapeutic management of ovarian malignant tumours continues to be a challenge for clinicians. Histopathological examination remains crucial in diagnosis. Accurate histopathological diagnosis, combined with clinical staging, facilitates prompt and appropriate treatment and timely patient management.
Reverse Intermetamorphosis Coexisting in a Case of Capgras Syndrome with Delusion of Subjective Doubles
Authors: Chatterjee shani Roy
Published: February 2024

‘Delusional misidentification syndrome’ is a fascinating phenomenon in which an individual misidentifies person, place, object or even themselves and falsely believes that they have been replaced or some sort of transformation has occurred. Capgras delusion, Fregoli delusion, Intermetamorphosis, Delusion of subjective doubles, all these phenomena broadly come under the psychiatric disorder of delusional misidentification syndromes. This case was established by its clinical characteristics along with associated clinical findings, the patient’s response to treatment in concurrence with psychological and neuro-cognitive theories. The present case report suggests that these symptomatology of misperception, miscomprehension and misinterpretation of others and of self are probably more prevalent than thought previously and should be actively sought and recognised in patients. This article sought to showcase a phenomenon which had a rare component of Reverse Intermetamorphosis along with Capgras Syndrome and Delusion of Subjective Doubles having no organic component in a 22 year old male patient who responded to pharmacotherapy with neuroleptics. The psychopathological symptoms demonstrating Capgras in itself is rare and inadequately researched. Presence of three distinctive patterns of symptomatology together in one subject is intriguingly unique.
Assessment of Morphological Diversity and Vegetative Growth Parameters of Fifteen Betel Vine Varieties Cultivated Along the Odisha Coast
Authors: Gochhi Sunil Kumar , Dey Surjendu Kumar
Published: February 2024

Betel vine (Piper betle) is a tropical evergreen plant renowned for its cultural and medicinal significance. With origins in Southeast Asia, its heart-shaped leaves, vibrant colors and aromatic properties contribute to its widespread cultivation. The study investigates the morphological diversity and vegetative growth parameters of fifteen betel vine varieties cultivated along the Odisha coast, with a focus on vine elongation, leaf dimensions, internodal length, leaf area, weight of fresh leaves, number of adventitious root production and the number of leaves per meter of vine. The results revealed significant variation among the varieties. Notably, vine elongation ranged from 39.5 to 68.8 cm/month, with the Golabandha varieties showing the highest rate. Leaf length varied from 8.84 to 20.24 cm, and the Chandrakana varieties displayed the longest leaves. Leaf breadth ranged from 4.46 to 15.3 cm, with the widest leaves found in Chandrakana varieties. Internodal length varied from 3.06 to 6.46 cm, with Gunthuni having the lowest internodes. Leaf area ranged from 38.04 to 177.37 cm2, with Chandrakana exhibiting the largest leaf area. Weight of fresh leaves varied significantly, with Chandrakana and Ralaba varieties having the highest and lowest weights, respectively. Cluster analysis grouped varieties based on their morphological characteristics, revealing distinct clusters related to leaf dimensions and growth parameters. Understanding the morphological diversity of betel vine varieties is crucial for identifying the superior varieties for sustainable cultivation and ensuring the quality of this culturally and economically significant crop.
Production, Nutritional Value and Toxicity of Kawal, a Fermented Product from the Leaves of Cassia obtusifolia (L.): A Review
Authors: Fangbo Amboussidi , Wilfred Ngaha Damndja , Joseph Collinlaw Ndouyang , Mbaiguinam Mbailao , Nicolas Njintang Yanou
Published: February 2024

Cassia obtusifolia is a plant of the Fabaceae family. Its leaves are eaten as a vegetable in several African countries. In some African countries like Chad and Sudan, the leaves are processed by fermentation in a solid state, called in arabic kawal, which is eaten with cereal couscous. The present study is a literature review on the production of kawal and similar products. The production of kawal remains made by craftsmen. After crushing, the leaves are incubated in a buried jar for a period that varies from 14 to 30 days, sun-dried for 3 to 5 days and are ready for consumption. Kawal has several nutritional benefits. Fermentation of C. obtusifolia leaves increases protein, calcium, magnesium and iron content by 38, 98, 75 and 47% respectively, and reduces the levels of secondary metabolites like polyphenols, tannins and phytic acid by 20, 6 and 47% respectively. Fermentation of C. obtusifolia leaves reduces the levels of secondary metabolites like polyphenols, tannins and phytic acid by 20, 6 and 47% respectively. However, some studies on the effect of kawal on albino rats and chicken’s growth have revealed signs of toxicity manifested through high level of serum transaminases and histopathology of the liver and kidneys. These data show that the fermentation of C. obtusifolia leaves improve nutritional value of this vegetable but does not considerably reduce secondary metabolites which could be considered as antinutrients and might be responsible of the toxicity in albino rats and chickens.
Fundamentals: Introduction and Survey
Authors: Stein Erwin
Published: January 2005

Volume 1, ‘Fundamentals’, contains 26 chapters with the basic methodological, analytical, algorithmic, and implementation topics and aspects of computational mechanics, written by well‐known mathematicians, mechanicians, engineers, and computer scientists.

It shall provide basic knowledge and tools as well as background information for Volumes 2 and 3, devoted to solid and structural mechanics as well as to fluid dynamics.

Volume 1 is structured as follows: the first 14 chapters treat
discretization methods
with error‐controlled adaptivity for elliptic problems, as finite differences, finite elements, boundary elements, mixed elements, finite volume elements, discontinuous elements, spectral methods, and wavelet techniques, followed by 3 chapters on
geometrical modeling, mesh generation, and visualization
. The next five chapters present solvers of algebraic equation systems, with emphasis on linear systems including eigenvalue problems, multilevel techniques, like Multigrid methods, cluster techniques, domain decomposition methods, and solvers for nonlinear systems, especially bifurcation problems. The last group of three chapters is devoted to
time‐dependent problems
, treating parabolic, and hyperbolic initial boundary value problems, especially Galerkin‐type approximations in space and time with duality techniques for the control of accumulation errors in time and thus of the numerical stability. Also boundary element methods are presented for transient parabolic and hyperbolic problems like the heat and diffusion–convection equation, acoustic scattering, and elastic wave propagation. Finally, numerical methods for the time‐harmonic Maxwell equations are presented.

Volume 1 thus is intended to provide a sound theoretical basis with numerous practical algorithms and tools for students, researchers, and practitioners.
Finite Element Methods
Authors: Brenner Susanne C. , Carstensen Carsten
Published: January 2005

This introductory chapter on the mathematical theory of finite element methods (FEMs) discusses itsh‐version for elliptic boundary value problems in the displacement formulation. Topics addressed range from a priori to a posteriori error estimates and also include weak forms of elliptic PDEs, Galerkin schemes, finite element spaces, adaptive local mesh refinement. Nonconformities and variational crimes as well as algorithmic aspects conclude the chapter.
Spectral Methods
Authors: Canuto Claudio , Quarteroni Alfio
Published: January 2005

Spectral methods represent a family of methods for the numerical approximation of partial differential equations. Their common denominator is to rely on high‐order polynomial expansions, notably trigonometric polynomials for periodic problems, and orthogonal Jacobi polynomials for nonperiodic boundary‐value problems. They have the potential of providing a high rate of convergence when applied to problems with regular data. They can be regarded as members of the broad family of (generalized) Galerkin methods with numerical evaluation of integrals based on Gaussian nodes. In the first part, we introduce the methods on a computational domain of simple shape and analyze their approximation properties as well as their algorithmic features. Next, we address the issue of how these methods can be extended to more complex geometrical domains by retaining their distinctive approximation properties.
Mixed Finite Element Methods
Authors: Auricchio Ferdinando , Brezzi Franco , Lovadina Carlo
Published: January 2005

Within the well‐known and highly effectivefinite element methodfor the computation of approximate solutions of complex boundary value problems, we focus on the often‐calledmixed finite element methods, where in our terminology the word ‘mixed’ indicates the fact that the problem discretization typically results in a linear algebraic system characterized by a null matrix on the main diagonal.

Accordingly, the goals of the present chapter are: (1) to sketch out that several physical problems share such an algebraic structure once a discretization is introduced; (2) to present a simple, algebraic version of the abstract theory that rules most applications of mixed finite element methods; (3) to give several examples of efficient mixed finite element methods; (4) finally, to give some hints on how to perform a stability and error analysis, focusing on a representative problem.
Discrete Element Methods
Authors: Bićanić Nenad
Published: January 2005

Discrete element methodscomprise a set of computational modeling techniques suitable for the simulation of dynamic behaviour of a collection of multiple rigid or deformable bodies. Most media can be treated as discontinuous at some level of observation (nano,micro,meso,macro), where the continuum assumptions cease to apply. This happens when the scale of the problem becomes similar to the characteristic length scale of the associated material and the interaction laws between bodies or particles are invoked, instead of the continuum constitutive law. Principal aspects of discrete element methodologies are discussed by considering(a) contact detection algorithm, (b) treatment of contacts, (c) deformability and material model of bodies in contact (rigid, deformable, elastic, elasto‐plastic etc), (d) small strain or large strain formulations, (e) number (small or large) and distribution (loose or dense packing) of interacting bodies, (f) modeling of boundary conditions, (g) possible fracturing or fragmentation and, (h) time stepping integration schemes (explicit, implicit). It is argued that there are many similarities between the apparently different discrete element methods e.g. distinct element method (DEM), discontinuous deformation analysis (DDA), non smooth contact dynamics (NSCD).
ArbitraryLagrangian–Eulerian Methods
Authors: Donea Jean , Huerta Antonio , Ponthot J.‐Ph. , Rodríguez‐Ferran A.
Published: January 2005

The aim of the present chapter is to provide an in‐depth survey of arbitrary Lagrangian–Eulerian (ALE) methods, including both conceptual aspects of the mixed kinematical description and numerical implementation details. Applications are discussed in fluid dynamics, nonlinear solid mechanics and coupled problems describing fluid–structure interaction. The need for an adequate mesh‐update strategy is underlined, and various automatic mesh‐displacement prescription algorithms are reviewed. This includes mesh‐regularization methods essentially based on geometrical concepts, as well as mesh‐adaptation techniques aimed at optimizing the computational mesh according to some error indicator. Emphasis is then placed on particular issues related to the modeling of compressible and incompressible flow and nonlinear solid mechanics problems. This includes the treatment of convective terms in the conservation equations for mass, momentum, and energy, as well as a discussion of stress‐update procedures for materials with history‐dependent constitutive behavior.
Nonlinear Systems and Bifurcations
Authors: Rheinboldt Werner C.
Published: January 2005

An overview of the basic local convergence theory of iterative processes for solving nonlinear systems of equations is given with applications to some of the principal computational methods, including Newton's method and its various related forms, and inexact Newton methods. Then, parameterized systems of equations and computational methods for the analysis of their solution manifolds are discussed, and for the scalar parameter case, homotopy methods and continuation methods are considered. Finally, an introduction to the computational study of the bifurcation behavior of parameterized systems is presented.
Finite Element Methods for
M
axwell Equations
Authors: Demkowicz Leszek
Published: January 2005

The article reviews fundamentals of Finite Element discretizations of time‐harmonic Maxwell equations. The paper includes a short introduction to Maxwell equations, derivation of the standard and regularized variational formulations, discussion of three fundamental Nedelec's elements in context of exact sequences, projection‐based interpolation, and the commuting diagram property. The presentation is biased towards
hp
‐discretizations and
hp
‐adaptivity.
Solids and Structures: Introduction and Survey
Authors: de Borst René
Published: January 2005

Volume 2 ‘Solids and Structures’ is concerned with the numerical analysis of solids and structures in the widest possible sense. Utilizing the basic methods outlined in Volume 1 ‘Fundamentals,’ a comprehensive picture is first given of numerical methods for solids and structures in the linear regime. Next, a wide variety of nonlinear theories are discussed, encompassing structural stability problems as well as instabilities that stem from the properties of the constituent materials. The volume also contains chapters that address computational problems that are specific to particular materials such as concrete, soils, composites, and biomaterials, and to forming processes.

Problems in which interaction between fluids and solids plays a role are covered next, for example, multiphase media, fluid–structure interaction, and structural acoustics. Other important topics that are treated include stochastic finite elements, parameter identification, and contact and the analysis of structural problems using boundary element methods.
Finite Element Methods for Elasticity with Error‐Controlled Discretization and Model Adaptivity
Authors: Stein Erwin , Rüter Marcus
Published: January 2005

The essential topics of the finite element method for linear and finite elastic deformations of solids are presented in this chapter from both the mechanical and mathematical point of view.

As a starting point, the nonlinear, and linearized theory of elasticity are derived in a rigorous way, followed by the classical variational principles of elasticity, which are the basis for the finite element method in its various forms. More precisely, the discrete variational approach of the (one‐field) Dirichlet minimization principle of the total potential energy is presented, followed by concise representations of the (two‐field) Hellinger–Reissner stationary dual‐mixed principle and the (three‐field) Hu–Washizu stationary mixed principle, including the main features of the associated finite element methods.

The main objective of this chapter is the systematic treatment of error estimation procedures and adaptivity for the linearized and finite elasticity problem covering both global and goal‐oriented a posteriori error estimators. The three basic classes, that is, residual‐, hierarchical‐, and averaging‐type error estimators are presented and applied to a fracture mechanics problem as an example.

A further challenging topic is the combination of error‐controlled adaptive finite element solutions with hierarchical model and dimension adaptivity of the underlying mathematical model, especially for thin‐walled structures where model expansion is necessary in subdomains with boundary layers and other disturbances.
Computational Fracture Mechanics
Authors: Ingraffea Anthony R.
Published: January 2005

The purpose of this chapter is to survey examples of historical and state‐of‐the‐art approaches of computational fracture mechanics. A global taxonomy of these approaches is defined and used as a roadmap for the chapter. Approaches are described and compared for their use in both the traditional role of computational fracture mechanics – calculation of crack front fields – and in the emerging role of prediction of material‐damage evolution and toughness.
Computational Geomechanics Including Consolidation
Authors: Carter John P. , Small John C.
Published: January 2005

A review is presented of the role of computational mechanics in geotechnical engineering. Included are discussions of the conventional deterministic techniques used for numerical modeling in geomechanics and a brief discussion of the stochastic techniques for dealing with the uncertainties encountered in geotechnical practice. Considerable emphasis is given to the methods commonly used for the solution of boundary and initial value problems. Significantly, the chapter also includes a discussion of the limitations of the various numerical modeling techniques. Constitutive modeling of soil and rock mass behavior and material interfaces is an essential component of this type of computing, and so a review of recent developments and capabilities of constitutive models for geomaterials is also included. Problems involving the interaction of the ground with other engineering structures are also addressed. Some of the concepts described in the paper are illustrated with examples taken from research and practice. Emphasis has been placed on the mechanical behavior of soil, but it is noted that many of the models and techniques described also have application in rock mechanics and rock engineering.
Computational Biomechanics of Soft Biological Tissue
Authors: Holzapfel Gerhard A.
Published: January 2005

Computational biomechanics of soft biological tissue is increasing our ability to address multidisciplinary problems of academic, industrial, and clinical importance. This article reviews parts of our current knowledge of the biomechanics of soft biological tissue, such as the arterial wall, the heart wall with the heart valves, and the ligament, as well as some of the available computational methods used to analyze them. The inherent complexities of the biological microstructure and function of the respective soft tissue are reviewed briefly, research effort related to the constitutive modeling catalogued, and a representative constitutive model for each considered soft tissue discussed in more detail. An account of residual stresses and biological processes such as growth and remodeling is provided. Finally, a few three‐dimensional finite element models that attempt to explain the integrated function of the respective soft tissue in terms of geometry, structure, and material properties are emphasized.
Stochastic Finite Element Methods
Authors: Gutiérrez Miguel A. , Krenk Steen
Published: January 2005

This chapter gives an overview of finite element related methods for the solution of problems in which the system has random properties. The notion of stochastic variables and fields is introduced and details are given for the normal and log‐normal distributions. Discretization methods for random fields and efficient algorithms for evaluation of the sensitivity to the random input are presented. The two dominating approximate methods for obtaining the statistical properties of the response from those of the stochastic properties of the system – the perturbation and the spectral method – are described in detail, and it is explained how statically determinate systems constitute a special case, permitting more general results. The final section deals with reliability methods, the purpose of which is to obtain the probability or a probability estimate, of a rare event, for example, failure. The methods are introduced by means of simple examples, with a view to making the text a self‐contained introduction and survey.
Boundary Integral Equation Methods for Elastic and Plastic Problems
Authors: Bonnet Marc
Published: January 2005

This chapter deals with formulations based on boundary integral equations (BIEs) for elastic and plastic problems. After a brief review of the basic integral identities of solid mechanics and issues associated with the singular character of the fundamental solutions, the collocation and symmetric Galerkin BIE formulations and the associated boundary element methods (BEMs) are presented, in their conventional form where the complete matrix equation is set up using numerical integration and stored. This approach being inadequate for large problem sizes, fast solution techniques are then reviewed, with emphasis on the fast multipole method. Next, BEMs in both collocation and symmetric Galerkin form are described for fracture mechanics and small‐strain elastoplasticity. The treatment of the hypersingular integrals arising in the integral representation of tractions on the crack surface or of strains at potentially plastic interior points is discussed, along with other issues. Shape sensitivity analysis techniques are also presented, based on either the direct differentiation of the primary elastic BIE or an adjoint solution. Finally, the symmetric Galerkin BIE is used to define a symmetric formulation for BEM–FEM coupling.
Multiscale and Stabilized Methods
Authors: Hughes Thomas J. R. , Scovazzi Guglielmo , Franca Leopoldo P.
Published: January 2005

This article presents an introduction to multiscale and stabilized methods, which represent unified approaches to modeling and numerical solution of fluid dynamic phenomena. Finite element applications are emphasized but the ideas are general and apply to other numerical methods as well. (They have been used in the development of finite difference, finite volume, and spectral methods, in addition to finite element methods.) The analytical ideas are first illustrated for time‐harmonic wave‐propagation problems in unbounded fluid domains governed by the Helmholtz equation. This leads to the well‐known Dirichlet‐to‐Neumann formulation. A general treatment of the variational multiscale method in the context of an abstract Dirichlet problem is then presented, which is applicable to advective–diffusive processes and other processes of physical interest. It is shown how the exact theory represents a paradigm for subgrid‐scale models and a posteriori error estimation. Hierarchicalp‐methods and bubble function methods are examined in order to understand and ultimately approximate the ‘fine‐scale Green's function’ that appears in the theory. Relationships among so‐called residual‐free bubbles, element Green's functions, and stabilized methods are exhibited. These ideas are then generalized to a class of nonsymmetric, linear evolution operators formulated in space–time. The variational multiscale method also provides guidelines and inspiration for the development of stabilized methods (e.g. SUPG, GLS, etc.) that have attracted considerable interest and have been extensively utilized in engineering and the physical sciences. An overview of stabilized methods for advective–diffusive equations is presented. A variational multiscale treatment of incompressible viscous flows, including turbulence is also described. This represents an alternative formulation of Large Eddy Simulation, which provides a simplified theoretical framework of LES with potential for improved modeling.
Spectral Element andhpMethods
Authors: Kirby Robert M. , Karniadakis George Em
Published: January 2005

Spectral/hpelement methods provide high‐order discretization, which is essential in the longtime integration of advection‐diffusion systems. Here we review the main formulations for simulations of incompressible, compressible, and plasma viscous flows, and present several examples with some emphasis on moving domains. The first generation of (nodal) spectral elements was limited to relatively simple geometries and smooth solutions. However, the new generation of spectral/hpelements, consisting of both nodal and modal forms, can handle very complex geometries by using unstructured grids and can capture strong shocks by employing discontinuous Galerkin methods. New implementation approaches have also been developed on the basis of multilevel parallel algorithms that allow dynamic p‐refinement at constant wall clock time. After two decades of intense developments, spectral element and hp methods are mature and efficient to be used effectively in applications of industrial complexity. They provide the capabilities that standard finite element and finite volume methods do, but, in addition, they exhibit high‐order accuracy and error control.
DiscontinuousGalerkin Methods for Computational Fluid Dynamics
Authors: Cockburn B.
Published: January 2005

The discontinuous Galerkin methods are locally conservative, high‐order accurate, and robust methods that can easily handle elements of arbitrary shapes, irregular triangulations with hanging nodes, and polynomial approximations of different degrees in different elements. These properties, which render them ideal forhp‐adaptivity in domains of complex geometry, have brought them to the main stream of computational fluid dynamics. In this paper, we study the properties of the DG methods as applied to a wide variety of problems, including linear, symmetric hyperbolic systems, the Euler equations of gas dynamics, purely elliptic problems, and the incompressible and compressible Navier–Stokes equations. In each instance, we discuss the main properties of the methods, display the mechanisms that make them work so well, and present numerical experiments showing their performance.
Industrial Aerodynamics
Authors: Chalot Frédéric L. , Perrier Pierre
Published: January 2005

This chapter describes the use of computational fluid mechanics at Dassault Aviation. A historical perspective gives a measure of the successive giant steps that have been made over the past 30 years. A rather detailed description of industrial codes leads to a good understanding of the key numerical concepts assembled to create a powerful tool for computational aerodynamics. The fundamental issue of turbulence modeling is addressed in detail. A large range of complex applications is described to illustrate the variety of problems solved. The status of the development and application of shape optimization techniques and multidisciplinary design are finally illustrated.
Finite Element Methods for Fluid Dynamics with Moving Boundaries and Interfaces
Authors: Tezduyar Tayfun E.
Published: January 2005

We provide an overview of the finite element methods we developed in recent years for computation of fluid dynamics problems with moving boundaries and interfaces. This class of problems include those with free surfaces, two‐fluid interfaces, fluid–object and fluid–structure interactions, and moving mechanical components. The methods developed can be classified into two main categories: interface‐tracking and interface‐capturing techniques. Both classes of techniques are based on stabilized formulations, and determination of the stabilization parameters used in these formulations is also highlighted here. The interface‐tracking techniques are based on the deforming‐spatial‐domain/stabilized space–time (DSD/SST) formulation, where the mesh moves to track the interface. The interface‐capturing techniques were developed for two‐fluid flows. They are based on the stabilized formulation, over typically nonmoving meshes, of both the flow equations and an advection equation. The advection equation governs the time‐evolution of an interface function marking the interface location. We also describe some of the additional methods we developed to increase the scope and accuracy of these two classes of techniques. Among them are the enhanced‐discretization interface‐capturing technique (EDICT), which was developed to increase the accuracy in capturing the interface, extensions and offshoots of the EDICT, and mixed solution techniques. The overview of these techniques is supplemented by a number of numerical examples from computation of complex flow problems.
Behavior in CHARGE syndrome: Introduction to the special topic
Authors: Hartshorne Timothy S. , Hefner Margaret A. , Davenport Sandra L.H.
Published: January 2005

Challenging behavior in children with CHARGE syndrome has been increasingly a concern of parents, educators, and health professionals. This article introduces the special topic in the American Journal of Medical Genetics on behavior in individuals with CHARGE syndrome. It provides background on CHARGE syndrome, diagnostic criteria, and the relationship of sensory and other physical deficits with both development and behavior. Four themes related to our developing understanding of behavior in CHARGE are described: children with CHARGE have behaviors different from those seen in other syndromes with or without deafblindness. The behavior they display is often very adaptive to their environment and to their own disabilities. These behaviors may be partially related to problems with arousal and self‐regulation. And, finally, all papers point to behavior as communication, especially within relationships, where it is essential for maximizing intellectual and social outcomes. © 2005 Wiley‐Liss, Inc.