bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiological diagnostics of triple negative breast cancer: a review
Authors: STADALNYKAITĖ Sigutė , BRIEDIENĖ Rūta
Published: July 2012

Background. Triple negative breast cancer has a poor prognosis. Therefore, it is vital to detect this subtype of breast cancer in its early stage. The imaging features of this clinically important subtype of breast cancer are not well known. There have been no published reports about radiological diagnostics of triple negative breast tumour in Lithuania. The purpose of this study was to review the imaging characteristics of triple receptor negative cancers in mammography, ultrasonography and magnetic resonance imaging (MRI).
Materials and methods. The published data for the period 2006–2011 concerning the imaging of triple negative breast cancer were analyzed. There were ten retrospective, ten prospective studies and five reviews. Five studies were on mammography imaging, three on both mammography and ultrasonography imaging, and five studies dealt with MR imaging data. Two studies analysed all three diagnostic methods.
Results. In mammography, triple negative breast (TRN) cancers often present as a mass and are most frequently round, oval or lobular in shape, less frequently being irregular. TRN tumours aren’t associated with calcifications. Moreover, architectural distortion is not a characteristic feature of triple negative breast cancer. In ultrasonography, TRN cancer appears as a parallel. TRN breast tumours mostly are irregular in shape and have a circumscribed margin. Attenuating posterior echoes and hypervascularity are not their characteristic features. In MR imaging, TRN breast cancer tends to have a lobulated, round or oval mass shape. Rim enhancement is identified in most of TRN tumours. Initially, rapid enhancement with a washout pattern (a sign of malignancy) does not usually apply to triple-negative breast cancers.
Conclusions. TRN breast cancer is difficult to diagnose, because usually it has no specific imaging signs typical of breast cancer. In mammography, TRN cancers aren’t associated with microcalcifications. In ultrasonography, attenuating posterior echoes and hypervascularity are not characteristic features of TRN tumours. In MRI, initially rapid enhancement with a washout pattern does not usually apply to triple-negative breast cancers.

Keywords: triple negative breast cancer, mammography, ultrasonography, magnetic resonance imaging
Helicobacter pylori infection, premalignant gastric lesions and gastric cancer in the Baltic States: a review
Authors: KUPČINSKAS Limas , MALFERTHEINER Peter
Published: July 2012

Helicobacter pylori (H. pylori) infection has been recognized as a human class I carcinogen in 1994 and linked with the development of gastric cancer in numerous studies. Gastric cancer still ranks as the second leading mortality cause among all cancers in the world and in the fourth place in Europe. High prevalence of H. pylori infection and high incidence of gastric cancer in adults are still characteristic of the Baltic States and resemble patterns in the Western and Northern European countries several decades ago. The recent decline in gastric cancer incidence and mortality as well as H. pylori prevalence in Lithuania, Latvia and Estonia reflects the worldwide trends. H. pylori induced diseases, however, still remain a significant burden for health care systems in the Baltic States. The relevance of H. pylori induced gastric diseases in the Baltic States has stimulated epidemiological, clinical as well as fundamental research on H. pylori infection, premalignant gastric conditions and gastric cancer. This paper reviews original research on H. pylori infection and related diseases in Lithuania, Latvia and Estonia during the period 1992–2011.

Keywords: Helicobacter pylori, atrophic gastritis, gastric cancer, Baltic States
Oncological outcomes of surgery in very high risk pT3b prostate cancer
Authors: MILONAS Daimantas , SMAILYTĖ Giedrė , TRUMBECKAS Darius , JIEVALTAS Mindaugas
Published: July 2012

Background. The aim of the study was to present the oncologic outcomes and to determine the prognostic factors of overall (OS) and cancer-specific survival (CSS) as well as disease-progression-free survival (DPFS) after surgery for pT3b prostate cancer.
Materials and methods. In 2002–2007, a pT3b stage after radical prostatectomy was detected in 56 patients. Patients were divided into groups according to the prostate-specific antigen (PSA) level (20 ng/ml), lymph nodes status (N0 vs. Nx vs. N1) and the Gleason score (6–7 vs. 8–10). The Kaplan–Meier analysis was used to calculate OS, CSS and DPFS. The Cox regression was used to identify the predictive factors of survival.
Results. Five-year OS, CSS and DPFS rates were 75.1%, 79.6% and 79.3%, respectively. The survival was significantly different when comparing the Gleason 6–7 and 8–10 groups. The 5-year OS, CSS and DPFS were 91.2% vs. 48.6%, 97.1% vs. 51.1% and 93.8 vs. 51.1%, respectively. There was no difference in survival among the groups with a different PSA level. The OS and CSS but not DPFS were significantly different when comparing the N0 and N1 groups. The 5-year OS and CSS was 84.4% vs. 37.5% and 87.3% vs. 47.6%, respectively. The specimen Gleason score was a significant predictor of OS and CSS. The risk of death increased up to 4-fold when a Gleason score 8–10 was present at the final pathology.
Conclusions. Radical prostatectomy may offer acceptable CSS, DPFS and OS rates in pT3b PCa. However, outcomes in patients with N1 and specimen Gleason ≥8 were significantly worse, suggesting the need of multimodality treatment in such cases.

Keywords: prostate cancer, locally advanced, surgery, outcome
Botulinum toxin therapy for nonneurogenic overactive bladder: first experience
Authors: ČERNIAUSKIENĖ Aušra , JANKEVIČIUS Feliksas
Published: July 2012

The paper presents early experience in the treatment of 20 patients with botulinum toxin injections into the detrusor muscle for the treatment of non-neurogenic overactive bladder (OAB) resistant to anticholinergic drugs.
Background. Botulinum toxin, a presynaptic neuromuscular blocking agent, reduces the involuntary bladder contractions that cause urgency, frequency and urge incontinence. We present our early experience with Dysport® injections into the detrusor for the treatment of non–neurogenic overactive bladder (OAB) resistant to anticholinergic drugs.
Materials and methods. Using intravenous anaesthesia, 20 patients (18 female and 2 male) with non-neurogenic OAB were injected with botulinum toxin A (Dysport®250 IU diluted in 4 ml normal saline) under cystoscopic visualization in 20 sites in the detrusor muscle, sparing the trigone. The urethral catheter was removed 24 hours after the procedure. Follow-up at 3 and 6 months after the injection included the Urogenital Distress Inventory UDI-6, the Incontinence Impact Questionnaire IIQ-7, clinical parameters and ultrasound measurement of bladder capacity and post-void residual urine volume.
Results. All 20 patients completed questionnaires and were examined after 3 and 6 months. At the 3-month follow-up, the median daytime micturation frequency decreased from 10.4 to 4.6 times (p < 0.0001) and at the 6 months follow-up 5 times (p < 0.0001), while nocturia decreased from 4.2 to 1.3 times after 3 months (p < 0.0001) and after 6 months to 2 times (p < 0.0001). Urgency decreased from 6 to 1.5 times after 3 months (p < 0.0001) and to 2 times after 6 months (p < 0.0001), and incontinence decreased from 4.2 times to 1.5 times after 3 months (p < 0.0001) and to 2.1 times after 6 months (p < 0.0001). The median maximum bladder capacity increased from 250 to 420 ml after 3 months (p < 0.0001) and decreased to 350 ml after 6 months (p < 0.0001). The post-void median residual urine volume was 10 ml. Only one patient mentioned a post-operative obstructive voiding difficulty. Eighteen (90%) patients were satisfied with the treatment. In two patients (10%), the amelioration of symptoms lasted for one month only, and later OAB symptoms
reappeared. Analysis of the UDI-6 and IIQ-7 questionnaires revealed that botulinum toxin A intradetrusor injection had decreased discomfort for patients and ameliorated their quality of life.
Conclusions. Botulinum toxin A injections in the detrusor are effective for the treatment of non-neurogenic OAB. Botulinum toxin A injections are a minimally invasive therapy and offer an alternative treatment for non–neurogenic OAB dysfunction resistant to conservative treatment. The durability of the treatment effect is the objective of the further investigation.

Keywords: botulinum toxin, overactive bladder, urinary incontinence
Histopathological and functional changes in the testicles of albino rats experimentally infected with Arcobacter butzleri
Authors: ADESIJI Yemisi Olukemi , EMIKPE Benjamin Obukowho , OPALEKUNDE Ahmed Bayo
Published: July 2012

Background. Arcobacter is an emerging zoonotic enteropathogen associated with spontaneous abortion, diarrhea and mastitis in domestic animals.
Materials and methods. Thirty male pathogen-free albino rats were infected with a single challenge of Arcobacter butzleri (108 cfu/ml) isolated from the stool of healthy pigs with the aim of investigating the effects of A. butzleri on rat testicular histology and spermatogenesis.
Results. In previously healthy male albino rats, A. butzleri caused testicular degeneration associated with reduced sperm count and motility.
Conclusions. The result of this study suggests that A. butzleri produces testicular degeneration and the associated disruption of spermatogenesis in albino rats; hence, its infertility potential in livestock industry and its economic importance should be further investigated.

Keywords: Arcobacter butzleri, testicular degeneration, infertility,pathogenicity, sperm count, albino rats
On prognostic connection between hard cosmic ray flux decrease and leaps of cardiovascular diseases in 2008–2009 in Vilnius
Authors: STYRA Dmitrijus , JUOZULYNAS Algirdas , USOVAITĖ Ana , GASPARIŪNAS Jonas
Published: July 2012

Data on a prognostic relationship between the hard cosmic ray flux (HCRF) and the leaps of cardiovascular diseases (CVD) in Vilnius in 2008–2009 are presented. A gamma spectrometer with a scintillation detector were used to register the HCRF near the ground surface. Data on CVD over a period of 24 months (2008–2009) were obtained from the Vilnius Ambulance Service. Information on CVD was selected for all age groups in accordance with the international codes for identification of diseases (ICD). The present study was restricted to time periods when the cosmophysical and medical data could be compared. For the processing of experimental results, empirical criteria in the analysis of HCRF and CVD were used. The criterion in HCRF change is a decrease of HCRF values by 200 impulses and more during a period of 4 hours. The CVD number exceeding the monthly average value by 10, 15, 20% was analysed. A correlation between the above parameters was studied in the range of 1–3-day period. The efficiency of the prognosis of CVD leaps by HCRF decrease in 1–2 days in 2008 was 74–82% and in 2009 65–70%, and for 2–3 days in 2008 54–60% and in 2009 63–65%. The human factor was analysed, too. Keywords: hard cosmic ray flux, cardiovascular diseases, connection, human factor
Time trends in avoidable cancer mortality in Lithuania 1992–2008
Authors: SMAILYTE Giedre , PAREIGIS Laurynas
Published: July 2012

Background. This study was aimed to evaluate achievements of medical health care
services in Lithuania by analysing time trends in avoidable cancer mortality of the whole Lithuanian population from 1992 through 2008.
Materials and methods. Data of the Lithuanian Cancer Registry for 1992–2008 were used to analyse avoidable cancer mortality trends. Mortality rates for all cancer and selected cancer sites were analysed. Age-standardised rates were calculated for both sexes. The age of the study subjects ranged between 5 and 75 years. The corresponding population data by age, sex and year were available from the Statistics
Lithuania.
Results. Cancer mortality has been decreasing continuously over time in both sexes. The degree of reduction in all-site cancer mortality was slightly higher in women (by 1.03% per year) than in men (by 0.83% per year). Mortality avoidable by medical intervention has been continuously decreasing since 1992 in both sexes by more than 2% per year, while mortality avoidable by primary prevention decreased only in men. Cancer mortality avoidable by secondary prevention was decreasing in women and increasing in men.
Conclusions. In Lithuania, a remarkable reduction in avoidable cancer mortality over the past decade has been found. However, the rate of reduction was slower in mortality avoidable by primary or secondary prevention methods than in mortality preventable by direct medical care, indicating that there is a need to put more effort towards primary and secondary prevention.

Keywords: avoidable death, cancer mortality, quality of health care
Parathyroidectomia: treatment of secondary hyperparathyroidism. Causes and prophylaxis of disease relapse
Authors: BEIŠA V. , LAGUNAVIČIUS K. , BEIŠA A. , STRUPAS K.
Published: July 2012

Background. The growing number of haemodialysis patients and the increasing their life expectancy within the past few years have resulted in a rise of long-term haemodialysis-associated complications. The aim of the paper is to present a case study of a successful surgical treatment of secondary hyperthyroidism and assess the causes of the disease.
Materials and methods. A 63-year-old male patient had been on haemodialysis for 18 years; he had undergone parathyroidectomy for secondary hyperparathyroidism 10 years ago. The relapse of the disease was suspected when the patient developed the onset of pruritus and muscle pain. The following tests were performed: biochemical markers of plasma calcium and parathyroid hormone, thyroid ultrasound examination, parathyroid gland 99 mTc MIBI scintigraphy, single photon emission computed tomography of the neck and mediastinum.
Results. Elevated calcium (2.73 mmol/l serum) and parathyroid hormone (1352 pg/ml blood plasma) levels were found. Ultrasound examination, 99 mTc MIBI scintigraphy and SPECT revealed parathyroid adenoma of the left inferior thyroid section. The patient underwent surgery in 2011. Remnants of the previously resected parathyroid gland were removed, and an accessory parathyroid gland was found within the thymus; this gland was removed, and partial autotransplantation was performed. The level of the parathyroid hormone decreased to 24 pg/ml during the day after surgery. The histological examination of the removed tissues was performed.
Conclusions. Accessory parathyroid glands are usually found within the thymus; therefore, any type of surgical treatment of secondary hyperparathyroidism should include thymectomy.

Keywords: parathyroid glands, secondary hyperparathyroidism, haemodialysis, parathyroidectomy
Phenotypic variation and genetic polymorphism of low-density lipoprotein exon 4 receptor gene among Jordanian familial hypercholesterolemia patients
Authors: ATOUM Manar , NUSIER Mohamad , H. AL DASOUQI Omran , NIMER Nisreen
Published: July 2012

Purpose. The aim of this study was to measure lipid profiles among severe and mild familial hypercholestrolemic (FH) patients and to screen unrelated families for LDL receptor (LDLR) gene polymorphism.
Methods. Fifteen FH patients and six controls were enrolled in the study. Total cholesterol (CH), triglyceride (TG), high-density lipoprotein (HDL-cholesterol), low-density lipoprotein (LDL) and ApoB-100 levels were measured spectrophotometrically. Patients were classified clinically into severe and mild, based on lipid profile phenotype and the presence of cardiovascular manifestation at the age of disease onset. Low-density lipoprotein exon 4 receptor gene polymorphism was screened by the SSCP method.
Results. FH severe phenotype patients had significantly higher total cholesterol levels (14.34 ± 1.14) mmol/L as compared with mild FH phenotype (10.13 ± 1.23 mmol/L) and experienced earlier symptoms in the childhood (9.25 ± 3.22) years as compared with those of mild phenotype, who did not experience symptoms until the mid of the fourth decade of life (36.7 ± 5.25 years). No significant difference was found between HDL-cholesterol, LDL-cholesterol, ApoB-100 among severe FH as compared with mild FH patients. All FH pedigrees showed the autosomal dominant mode of inheritance. SSCP results showed a wide spectrum of LDL exon 4 gene polymorphism among severe and mild phenotypes, which differed from control.
Conclusions. There are statistical differences between severe and mild phenotype FH patients in total cholesterol, triglyceride and the age of biological expression among FH Jordanians. FH patients showed a wide spectrum of gene polymorphism within the LDLR exon 4 gene. These polymorphisms were different among FH families; this may be related to founder factors, such as the degree of consanguinity among FH patients’ parents and shed light on the importance of the role of genetic screening and counseling in reducing the risk of occurrence of the new severe FH phenotypes that develop severe complications early in life and need LDL aphresis, as well as on the importance of cascade screening to trace and identify people at genetic risk, using family tracing, for an early diagnosis of the mild FH phenotypes that can be treated with lipid lowering therapy and life style changes early to prevent later cardiovascular complications.

Keywords: familial hypercholesterolemia, low-density lipoprotein, receptor, homozygous, heterozygous, SSCP, Apo B-100
Public health bureaus: new players in health improvement in Lithuania
Authors: KALĖDIENĖ Ramunė , ŠČEPONAVIČIUS Audrius
Published: July 2012

Particular emphasis in the development of the public health care system in Lithuania was put on strengthening public health at the municipal level. This paper aims at investigating the possibilities and barriers of the public health reform in Lithuania by
analyzing the experience of establishing public health bureaus as the major players in public health development at the municipal level. The Lithuanian National Public Health Strategy and Action Plan have been adopted by the Government in 2006. Ministry of Health prepared legal acts and programmes that encourage local authorities to establish public health bureaus. By the end of 2010, 32 municipal Public health bureaus were set up. The core main functions of the bureaus are public health promotion, monitoring public health and child health care. The first steps of the bureaus were complicated by the lack of well-developed strategies of action and local support, as well as by financial challenges. For strengthening the position of the bureaus in society, benefits of these newly established institutions should be widely presented to the public; sustainable financing mechanisms and a focus on intersectoral cooperation, integrating public health into primary health care are needed; also, human resource development should be foreseen. In spite of the rather challenging beginning, bureaus are starting to provide means by which local governments, in partnership with the service providers, other stakeholders and the community can plan and implement public health services and programmes and play a significant role in improving the health of population.

Keywords: Lithuania, public health reform, municipal level, public health bureau
A SECRETÁRIA EXECUTIVA NO PROCESSO DE GOVERNANÇA CORPORATIVA NA EMPRESA FAMILIAR
Authors: Fonseca Elisandra C. , Parra Priscila S. , Azevedo Maurício S. , Lopes Paulo C.
Published: July 2012

Empresas familiares têm enfrentado dificuldades quando se trata de sucessão familiar. Diante de tais dificuldades, sejam elas ocasionadas por questões sentimentais ou por conflitos de interesse, as empresas têm buscado ferramentas alternativas que buscam minimizar tais dificuldades, de forma a acomodar todos os interesses no processo. A Governança Corporativa tem se apresentado, então, como um eficiente meio nesse processo de conflito de gerações, além de fortalecer a empresa, reforçando suas competências e ampliando suas estratégias, contribuindo assim para resultados positivos e menos voláteis. O profissional de secretariado executivo pode exercer um importante papel no processo de implantação e manutenção da Governança Corporativa. Seu amplo conhecimento pode facilitar a perpetuação da Cultura Organizacional, atuando como facilitador, colaborador e mantenedor do bom ambiente familiar, da confiança e da boa comunicação entre conselheiros, família e funcionários. Este artigo busca mostrar, através de um estudo de caso, como o Grupo Maranhão enfrentou o processo de implantação da Governança Corporativa, a fim de profissionalizar o processo de sucessão familiar, e qual foi a importância da secretária executiva nesse processo.
A FORMAÇÃO DO PROFISSIONAL EM SECRETARIADO EXECUTIVO NO MERCADO DE TRABALHO GLOBALIZADO
Authors: Martins Cibele Barsalini , Terra Penha Mendes , Maccari Emerson Antonio , Vicente Ismar
Published: July 2012

Neste estudo busca-se propor uma reflexão sobre o processo de formação educacional do profissional em Secretariado Executivo, visando a identificar as transformações ocorridas no âmbito do trabalho e suas implicações em um contexto globalizado. Para tanto, aborda-se as questões relacionadas com a evolução educacional da mulher, bem como se apresentam alguns aspectos do trabalho feminino tais como: dupla jornada de trabalho, remuneração diferenciada por gênero, qualificação profissional e principalmente o enfoque dado ao processo de trabalho nos países centrais, semiperiféricos e periféricos, afetados pelo processo de globalização. Este trabalho de base bibliográfica apresenta como principais pressupostos teóricos os estudos da Mulher e a Educação abordados por Pimentel (1998), Valdéz & Gomariz, (1995); o Histórico da Mão-de-obra Feminina na visão de Antunes, (2000), Munhoz, (2000); e, por fim, a Globalização e seus efeitos abordados pelos autores Hobsbawn, (2000), Forrester, (1997), entre outros. Os resultados do estudo apontam que o profissional em Secretariado Executivo, apesar de que todos os preconceitos e dificuldades enfrentadas ao longo de décadas e principalmente pelos efeitos da globalização, têm conquistado espaços próprios no mercado de trabalho e vem procurando constante aperfeiçoamento educacional notadamente por meio de cursos superiores objetivando melhorar, cada vez mais, sua qualificação profissional.
ARQUIVOS E DOCUMENTOS EMPRESARIAIS: DA ORGANIZAÇÃO COTIDIANA À GESTÃO EFICIENTE
Authors: Dudziak Elisabeth Adriana
Published: July 2012

O objetivo deste artigo é apresentar e discutir o processo de planejamento, organização, guarda e gestão de arquivos e documentos empresariais, do ponto de vista do profissional de secretariado executivo. Inicia-se o texto a partir da introdução ao cenário atual com foco na dinâmica global, as demandas de serviço e o papel essencial do secretário executivo na empresa. Apresenta-se uma revisão teórica dos principais conceitos e normas internacionalmente adotadas na organização de arquivos. Estabelece-se a necessidade de realizar, mais do que a simples organização de arquivos, a gestão de documentos e arquivos. Com base nesta premissa, são apresentadas as bases teórico-conceituais para a implantação de um Serviço de Documentação e Arquivo, a partir das principais tipologias documentais existentes nas empresas e respectivos critérios classificação e temporalidade de guarda de documentos. Discute-se a importância do planejamento estratégico, tático e operacional da gestão de arquivos. Finaliza-se o artigo com a descrição das etapas de implantação de um Serviço de Documentação e Arquivo e o código de ética do gestor de documentos.
AS REPRESENTAÇÕES GRAMATICAIS DE ALUNOS DE SECRETARIADO EXECUTIVO
Authors: Martins Emili Barcellos , Kundman Maria Sabina
Published: July 2012

Qual deve ser o lugar ocupado pela gramática no ensino/aprendizagem de uma língua estrangeira, principalmente no ensino voltado para futuros profissionais de secretariado? Apesar de ser vista atualmente por muitos como uma componente de pouca importância, a gramática continua a desempenhar um papel de grande valor no ensino de qualquer língua, seja ela materna ou estrangeira. Por acreditarmos que o aprendiz ocupa o centro de todo processo de ensino/aprendizagem, objetivamos com este estudo identificar as representações que alunos de um curso de Secretariado Executivo Trilíngüe de uma universidade do interior de Minas Gerais possuem acerca de questões referentes ao ensino de gramática, tanto do português quanto do francês. Um questionário foi elaborado a partir dos modelos de Besse e Porquier (1984) e de Germain e Séguin (1998) e neste trabalho são apresentados os resultados obtidos nesta pesquisa.
Nondestructive Testing and Evaluation of Composite Aerospace Structures
Authors: Smith John P. , Shark Lik‐Kwan
Published: July 2012

There is a broad range of approaches and technologies used for nondestructive testing and evaluation (NDT&E) of composite aerospace structures. The aim of this article is to provide an overview of the most common measurement methods used in the aircraft manufacturing sector for nondestructive detection of internal defects in carbon fibre composite structures, as well as signal and image processing techniques available for computer‐assisted evaluation. The problems and challenges faced by NDT&E are first explained in terms of typical composite aerospace components, typical defects, and general inspection requirements. Four most common production NDT techniques are then presented in detail, covering principal aspects of ultrasound, radiography, shearography, and thermography in terms of their operating principles, performance, and applications to composite aerospace components. This is followed by signal processing methods for NDT signal enhancement, detection, and restoration as well as image processing methods for mosaicking of multiple NDT images, registration with component CAD model, fusion of multimodality NDT images, defect visualisation, and automatic defect detection. Finally, future NDT&E trends are highlighted based on current technology progress.
Carbon/Polymeric Composites Autoclave Cure Monitoring with Optical Fiber Bragg Grating (FBG) Sensors
Authors: Olivier Philippe , Mulle Matthieu , Paris Christophe , Collombet Francis
Published: July 2012

The manufacturing of a thermoset matrix composite part is quite complex. The curing of this kind of composites is commonly controlled by curing duration, temperature, pressure, and vacuum. On one hand, in order to produce fully cured and compacted and high quality parts, a reasoned and optimum choice must be done. On the other hand, and all the more so as regards thermoset matrix composites, the curing parameters may induce some irreversible effects on several parameters of the ensuing laminated part. For all these reasons, since numerous years, cure monitoring has been paid of a great attention.

In this contribution, the reader will be first provided with a condensed survey (including more than 100 references) of the main methods developed from more than 40 years to monitor the changes occurring in a composite material during its curing. In the broad field of real‐time cure monitoring, a focus on optical fibers Bragg grating (FBG) and their use for cure monitoring purposes will be made in this article. Some original results are given after a brief introduction about FBG.

The selection of a sensing technique depends on the desired results. Nevertheless, the advantages and the drawback of each technique will not be discussed here. The reader will easily find detailed comments in the numerous references proposed at the end of this article.
SoftTissueRepair andRegeneration: Composite Materials Toward the Design of Advanced Prostheses and Scaffolds
Authors: Gloria Antonio , Russo Teresa , D'Amora Ugo , De Santis Roberto , Ambrosio Luigi
Published: July 2012

The restoration of tissue biomechanical function represents a great challenge, underlining the need to mimic tissue structure and mechanical behavior through suitable prosthesis and scaffold designs. For this reason, several materials, technologies, and designs have been widely proposed and studied from an experimental and/or a clinical point of view. Polymer‐based composite materials are suitable candidates for applications where high strength‐to‐weight and stiffness‐to‐weight ratios and specific performances are required. Taking into account tissue structure‐function relationships, the design of biomimetic composite devices able to reproduce the multiscale structural hierarchy of complex tissues represents a crucial feature for tissue repair and regeneration.

In particular, this article aims at stressing the importance of polymer‐based composite materials to design advanced prostheses and scaffolds for soft tissue engineering, with a special focus on tendons, ligaments, intervertebral disk, and meniscus.
Composite Smart Panels for Active Control of Sound Radiation
Authors: Gardonio Paolo
Published: July 2012

This article presents a short introduction to the physics of composite smart panels for the rednuction of sound radiation. The principal actuation and sensing properties of distributed piezoelectric strain transducers embedded in thin panels are illustrated in terms of equivalent sensing and excitation functions. Also the physical features of active structural acoustic control and active vibration control systems using either single‐channel or multiple‐channel feed‐forward and feedback controllers are revised.
Continuum Damage Mechanics
Authors: Lapczyk Ireneusz
Published: July 2012

In the last five decades, continuum damage mechanics has proven to be a valuable tool to study material degradation. Many damage models have been developed that allow an accurate description of damage processes for a wide range of materials. At the same time, much effort has been expended to develop robust algorithms for obtaining numerical solutions to problems with damage. Some of the models have already been implemented in commercial finite element codes and have become a valuable tool in helping engineers predict behavior of engineering structures. In this article, a general framework for modeling damage, based on the theory of irreversible thermodynamics with internal variables, is outlined. Special attention is devoted to issues related to the numerical implementation of material models with damage, such as mesh sensitivity of the solution and convergence difficulties.
Damage Mechanisms in Cross‐Ply Fiber‐Reinforced Composite Laminates
Authors: Kashtalyan Maria , Soutis Constantinos
Published: July 2012

The fracture process of composite laminates subjected to static or fatigue in‐plane loading involves a sequential accumulation of intra‐ and interlaminar damage, in the form of matrix cracking and crack‐induced delamination, before catastrophic failure. Matrix cracking parallel to the fibers in the off‐axis plies is the first damage mode observed. It triggers development of other harmful resin‐dominated modes such as delaminations. The present article reviews experimental and theoretical studies into the damage mechanisms in cross‐ply composite laminates within the framework of damage micromechanics and discusses the effect of intra‐ and interlaminar damage on the behavior and mechanical properties of laminates, including the work of the authors on modeling matrix cracking and crack‐induced delaminations.
Externally Bonded Masonry Structures
Authors: Lignola Gian Piero , Ceroni Francesca , Balsamo Alberto , Prota Andrea , Manfredi Gaetano
Published: July 2012

Fiber‐reinforced polymer (FRP) materials can be very reliable materials for the retrofit of unreinforced masonry structures. After a brief introduction on the wide variety of materials, typologies, and construction techniques of masonry structures, the main principles of unreinforced masonry assessment are discussed. The knowledge of typical masonry damages and failure modes allows the reader to understand the basis of retrofit design using innovative composite systems and the essential principles for the selection of materials and systems for masonry retrofit. The bond mechanism, at the base of the structural performance of externally applied FRP, is discussed and then peculiar aspects of in‐plane and out‐of‐plane masonry retrofits are debated. Shear, flexural, and confinement applications are considered at both local and global scales. Peculiarities in the FRP retrofit of masonry‐curved structures complete the review of retrofit applications. Basic mechanical principles as well as provisions from current international design guidelines or innovative theories from up to date scientific literature are discussed as well.
Fatigue Stiffness
Authors: Vassilopoulos Anastasios P.
Published: July 2012

Service loading of structures affects their strength and stiffness. In many cases, the influence of the stiffness changes on the structure is quite large since these changes also affect the deflections, cause dimensional changes, alter the structure's vibration characteristics, and affect the load or stress distributions inside the structure. Several generic sources of stiffness changes can be identified in various degrees. Transverse cracking, delamination, fiber breakage, and fiber‐matrix debonding are some of the defects that occur in laminated composites. Stiffness changes can be used for the development of fatigue life modeling and prediction methodologies as well, since stiffness can be monitored in a nondestructive way during the operation of a structure. These subjects are discussed in this article through the demonstration of the fatigue behavior and stiffness degradation patterns of several multidirectional composite laminates and adhesively bonded composite joints.
Fibrous Preforms and Preforming
Authors: Michaud Véronique
Published: July 2012

This article introduces the concept of preforms and preforming. A preform is defined as an assembly of yarns or textiles, which is generally stabilized by introduction of additional material, yarns or a binder powder. We first provide a brief review of textile forms and processes and then introduce the various preforming techniques, from 2D textiles or directly from the individual yarns. We finally address technical and scientific issues, including the mechanical behavior of the textile during preforming, and the influence of preforming on the permeability of the fiber assembly.
Liquid Crystalline Composite
Authors: Isayev Avraam I.
Published: July 2012

A review of novel technologies for manufacturing composites involving liquid crystalline polymers (LCPs) is presented. In particular, this review provides a classification scheme of various types of LCPs, with a special emphasis paid to the history, key approaches, milestones in developments of thermotropic LCPs, and their commercialization. Methods of characterization of LCPs by optical and electron microscopy, X‐ray diffraction, NMR, light scattering, and thermal, rheological, and mechanical techniques are discussed. The development of the concept of self‐reinforced orin situcomposites based on blending LCPs with flexible‐chain polymers and LCPs with other LCPs is presented. In these composites, the dispersed fibrous reinforcing LCP species in polymer matrices are not actually present before the processing of the resin, but come into existence during the processing step. Various aspects of manufacturing of these composites are discussed including methods of mixing and compounding, transition temperatures, different factors governing LCP fibrillations, effects of LCP on crystallization of thermoplastic matrices, rheology of composites, and the use of LCP as a processing aid for thermoplastics. Special attention is paid to manufacturing and mechanical properties of the composites based on LCP/thermoplastic, LCP/LCP and ternary blends, and LCP/thermoplastic and LCP/LCP laminates. The effect of compatibilization and anisotropy of composites are also considered along with proposed approaches to reduce their anisotropy. Finally, various existing and future possibilities for industrial applications of self‐reinforced composites are discussed.
Manufacturing: Economic Consideration
Authors: Park Chung Hae , Lee Woo Il
Published: July 2012

In this article, cost is defined and various components of cost to manufacture composite material products are presented. These components include material cost, labor cost, and tooling and capital cost. Factors constituting these components of cost are discussed in detail. Various costing methods being used in practice are introduced. Finally, it is explained how efforts to protect the environment affect the cost of composites.
Matrix‐Controlled Failure Modes of Polymeric Composites
Authors: Guedes Rui M. , de Moura Marcelo F. S. F.
Published: July 2012

The intention of the present article is to provide an overview of up‐to‐date understanding of matrix‐controlled failure modes. This subject covers distinct themes including failure criteria, micromechanics analysis, and theory of fracture mechanics. The effect of environmental conditions, rate dependency, delayed failure, and fatigue are also examined.
Microscopy: High Resolution Electron (
HREM
)
Authors: Igata N.
Published: July 2012

The properties of composite materials are closely related to the microstructure of the fibers or particles, matrix, and interfaces that can be studied, thanks to the use of a high resolution electron microscopy (HREM). It represents, in fact, one of the most powerful methods that can be used to clarify the microstructure of composite materials.

In this article, a brief description of the structure of HREM is reported first to describe some principles that are to the base of the image formation. Moreover, a discussion on the specimen preparation is reported, and finally, some applications to some composite materials are explained.
Multifunctional Low Loss Ceramic–Polymer Composites for Microwave Applications
Authors: Wang Hong , Xiang Feng , Yang Haibo , Li Kecheng
Published: July 2012

This article reviews the state of the art in low loss multifunctional ceramic‐polymer composites for microwave applications. First, the process technology and modeling method for ceramic‐polymer composites are briefly presented. Second, low loss ceramic‐polymer composites with enhanced dielectric behavior are reviewed. Third, flexible dielectric composites are studied by choosing an elastomer with low microwave dielectric loss as matrix and high permittivity microwave ceramics as fillers. Improving the permittivity while retaining the flexibility is achieved by improving the ceramic filler particle's properties, composites structures, and the technology procedures. Microwave composites with high permittivity, low dielectric loss, and certain flexibility are obtained. Fourth, a kind of low loss dielectric‐magnetic composite was developed with the aim to integrate the dielectric properties and magnetic properties. The results show good success in lowering the dielectric loss and extending the cut‐off frequency of the magneto‐dielectric composites. Examples of new applications based on the low loss ceramic‐polymer composites are given and the future trends for development pointed out.
Natural Composites: Fiber Modification
Authors: Baltazar‐y‐Jimenez Alexis , Awal Abdul , Sain Mohini
Published: July 2012

In this article, natural composites are defined as vegetal or lignocellulosic fiber‐reinforced polymer composites. Several surface modification methods appropriate for vegetal fibers are discussed in three broad categories: physical or chemical methods designed to improve water repellence, improve adhesion to a polymer matrix, and methods for increasing thermal and fire resistance. A brief outlook of alternative surface modification methods for vegetal fibers is also presented.

A number of surface modification methods may be used with synergistic effect. However, a delicate balance exists between technological feasibility and cost, whatever this may be. Ideally, selecting a useful method to modify the performance of vegetal fibers is a holistic process that requires of balancing materials' properties, with economic and environmental considerations.
Polycarbonate Composites
Authors: Pisanova Elena
Published: July 2012

Polycarbonate (PC) is one of the most widely used consumer materials, both in its reinforced and unreinforced forms. The introduction of reinforcement improves mechanical and other properties while maintaining the desirable properties of PC, such as ease of manufacturing, chemical resistance, and thermal stability. Reinforcements include glass and graphite fibers, particles, and nanofibers and nanoparticles. An important feature of PC is its ability to form mixtures with a wide variety of other polymers and elastomers, which gives a very wide range of matrixes and properties.
Polymer/Wood Composites
Authors: Renner Károly , Móczó János , Pukánszky Béla
Published: July 2012

The use of thermoplastic composites reinforced with natural fibers is a mature technology now with a considerable growth rate. The properties of all polymer/wood composites are determined by four factors: component properties, composition, structure, and interfacial interactions. Matrix stiffness determines the extent of reinforcement, while aspect ratio and particle size are the most important characteristics of the wood. Wood content is usually very large in order to achieve maximum effect and lowest possible price. At large fiber content, wood particles can touch each other purely from geometrical reasons resulting in a kind of aggregation which decreases composite strength. Alignment of the fibers, that is, orientation is the other structural factor that influences composite properties considerably. Interfacial interactions are inherently weak in most commodity thermoplastic/wood composites. External load initiates various micromechanical deformation processes in these materials: shear yielding of the matrix, debonding, fiber pullout, or fiber fraction may occur simultaneously or consecutively. Because of easy debonding, interactions must be modified usually by coupling in most composites. In the case of strong interfacial adhesion, the inherent strength of the wood particles may limit the maximum strength of the composites. A brief summary of processing technologies and main application areas are also presented at the end of the article.
Polysulfone Thermoplastic CompositesAdapted fromPolysulfone Thermoplastic Composites, First Edition.
Authors: Michno M. J. , Matzner M. , Kwiatkowski G. T.
Published: July 2012

Thermoset composite systems, such as those based on epoxy resins, have been known for a long time. These systems suffer from a series of drawbacks, which include a limited number of fabrication processes, the inability to reuse scrap or rework cured parts, and a general lack of toughness. These drawbacks are related to the need to perform chemical reactions on resin intermediates that lead to cross‐linked polymer networks. The continuous development of new thermoplastic resins has provided novel, tough materials that maintain attractive properties over a wide temperature range, and that can be used for prolonged periods at elevated temperatures. Concurrently, novel, rapid fabrication processes are being developed to provide lower cost options for production of composite structures. Examples of engineering high performance polymers useful in composite structures include the amorphous polysulfones and the closely related crystalline poly(aryl ketone)s.

Polysulfone thermoplastic composites are presented in this article; in particular, polysulfone polymers and their properties such as mechanical and thermal properties are discussed. Finally, some exemples of polysulfone composites are reported.
Particulate Composites by Powder Injection Molding
Authors: German Randall M.
Published: July 2012

A few unique aspects of composite structures are attained using a powder injection molding (PIM) approach. First, since the materials are not melted, it is possible combine different materials into a single component. Significant flexibility is possible by adjusting the size, size ratio, amount, and particle shape. Thus, insoluble systems such as aluminum–silicon carbide or tungsten–copper are fabricated from mixed powders. An alternative is to injection‐mold the high temperature phase and infiltrate the porous skeleton using liquid metal. But the most important advantage of powder routes is in the ability to fabricate very complicated shapes. This is the key advantage in microelectronics, human implants, and wear applications. It is in this regard that the PIM process excels.
Recycling of Carbon Fiber Composites
Authors: Pisanova Elena
Published: July 2012

The recycling of carbon fiber composites involves significant technical and economic challenges. Current work is focused on the development of efficient and cost‐effective methods to break down the matrix and extract the fibers without damaging the fibers or degrading their mechanical properties. There are several drivers for this effort, including the desire for environmentally friendly waste recycling, governmental regulations, and economic advantages for post consumer applications in automotive and other industries.
Recycling Thermoset Composite Materials
Authors: Pickering Stephen J.
Published: July 2012

In this article, the recycling of thermoset composites is described. Thermosetting polymers, once cured, cannot be remolded by melting and so the methods used for recycling thermoplastics cannot be used. Recycling is therefore carried out by one of two methods. The waste composite materials may be reduced in size to make powdered and fibrous materials that may be used as constituents in new composites. Alternatively, thermal and chemical techniques are used to remove the thermosetting polymer from the fiber reinforcement to produce a fiber recyclate, potentially of high value, that can be used as a reinforcement in new composites. The current state of development of these recycling routes is described and applications for the recycled material considered. Some areas for future research are identified.
Resin Infusion Under Flexible Tooling (RIFT)
Authors: Summerscales John
Published: July 2012

The traditional processes for the manufacture of high performance composite shell structures are (i) vacuum bagging (VB)/VB with autoclave cure VB(A), (ii) resin transfer molding (RTM), and (iii) compression molding. Over recent years, there have been a number of novel “infusion” processes introduced, which span the gap between VB(A) and RTM. The new processes are known by a confusing set of names or acronyms—each company uses a distinct name, yet often the processes are near identical. The infusion processes can be mapped onto four distinct generic processes:

Resin infusion in the plane of the fabric (Type I),

Resin infusion with a flow medium/transport or distribution mesh (Type II),

Resin film infusion (Type III), and

Semipreg techniques (Type IV).

This article describes the attributes of each of the four variants above and considers their relative advantages and issues.
Space Environment Effects on Polymer Matrix Composites
Authors: Katz Sari , Grossman Eitan
Published: July 2012

Polymer matrix composites (PMCs) that exhibit high specific strength, high stiffness, and low coefficient of thermal expansion are widely used in spacecraft as structural materials and other components. The composites are therefore exposed to the harsh space environment which varies with the spacecraft's orbit, the mission duration, and the solar activity. The effects of the space environment components, such as, atomic oxygen, ionizing radiation, thermal cycling, and more, on PMCs are described. These effects are studied via ground simulation andon‐orbitmaterials' exposure. The reaction to the individual and synergistic effects is described. Also included are future expectations for improvement of materials' durability to the space environment mainly by the use of nanotechnology.