bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of wear and corrosion resistant PVD‐coatings for magnesium alloys
Authors: Hoche H. , Allebrandt D. , Scheerer H. , Broszeit E. , Berger C.
Published: April 2007

Although magnesium alloys became popular in the first half of the 20th century, the bad corrosion properties prevented their breakthrough in industrial mass production. Since the technology for the production of high purity alloys was introduced in the 1970s, magnesium alloys became more and more in the focus of industrial attention. Today magnesium alloys are state of the art in structural parts in automotive industry. Despite its outstanding properties like good castability, low density and nearly unlimited availability the negative aspects like weak corrosion and wear behaviour still limit the application of magnesium in industry [1].

So, the only economic solution is the deposition of a coating or a suitable surface treatment which provides both, wear and corrosion resistance. Today, plasma electrolytic anodisations are state of the art [2–5]. They provide acceptable corrosion resistance and protect the magnesium from mechanical damage due to their high hardness. On the other hand, their high porosity limits their use in combination with electrochemically noble materials, leading to galvanic corrosion [6]. In addition, the high surface roughness of the plasma electrolytic anodisations restricts their use in tribological applications, particularly under dry sliding conditions [7].

On the other hand, due to the high life time recommendations the application of magnesium in the automotive industries motion component field is a long term process. Nevertheless, there is a quite high industrial interest to apply magnesium in the motion component field in consumer applications like do‐it‐yourself or gardenig. Some examples are motor components of lawnmovers, motor saws or drills. Especially for these fields of application there are quite high demands on the corrosion properties due to undefined storage and the conditions during usage.

In order to achieve smooth surfaces with high quality, the PVD technology moves into the centre of interest. Since the 1980s PVD coatings are well established and widely used for different industrial applications, mainly for steel and tool coatings. The authors were the first who carried out serious studies on the development of PVD coatings for magnesium alloys since 1999 [6, 7].

The extensive research activities lead to the recent development of a coating system, which provides both, good wear properties as well as good corrosion behaviour.
Bruchanalyse an Hohlgläsern
Authors: Hosemann H.‐J. , Hof P.
Published: April 2007

Die Bruchanalyse ist ein wichtiger Bestandteil der Klärung von Schadensfällen von Hohl‐ oder Verpackungsgläsern. Da es sich bei Schadensfällen mit zum Beispiel unter Innen‐Überdruck stehenden Flaschen häufig auch um gesundheitliche Schäden handelt, kommt der Bruchanalyse und der damit verbundenen Ursachenforschung eine große Bedeutung zu. Verschiedene Merkmale auf den Oberflächen von Glasbruchstücken und das gesamte Bruchbild selbst geben Hinweise auf die Rissausbreitungsrichtung, die im Bruchfalle anliegenden Spannungen und auf die Ursache der Spannung. Eine Rekonstruktion der Flasche selbst ist ein weiteres hilfreiches Mittel zur Ursachenforschung. Die Unterschiede der verschiedenen Oberflächenmerkmale werden im Folgenden erläutert. Außerdem werden an hand zum Beispiel von Bruchbildern verschiedener Bruchursachen und ‐mechanismen vorgestellt und diskutiert
Verhalten geschweißter Magnesiumlegierungen unter mechanisch‐korrosiver Komplexbeanspruchung
Authors: Eppel K. , Ellermeier J. , Troßmann T. , Berger C.
Published: April 2007

Neben dem weit verbreiteten Einsatz von Magnesium‐Gusslegierungen bieten Magnesium‐Knetlegierungen ein hohes Leichtbaupotenzial insbesondere in der Automobilindustrie.

Die Verarbeitung von Walz‐ bzw. Strangpressprodukten aus Magnesiumlegierungen (Profile und Bleche) erfordert geeignete Fügeverfahren zur Verbindung dieser Halbzeuge. Im Rahmen der Realisierung von Leichtbaukonzepten werden hohe Anforderungen an die Werkstoffe und Fügeverfahren gestellt, sodass die Eigenschaften der Verbindungen, sowohl im Hinblick auf Wirtschaftlichkeit und mechanische Festigkeitskennwerte, als auch bezüglich ihres Korrosionsverhaltens, von großem Interesse sind.

Beim Schweißen von Magnesiumlegierungen kommt es zu Beeinflussungen der Oberfläche, des Eigenspannungszustandes und des Gefüges. Diese hängen insbesondere von der eingebrachten Wärme ab und sind somit abhängig vom Schweißverfahren und den Verfahrensparametern und beeinflussen das Korrosionsverhalten in der Schweißzone.

Es werden Untersuchungen zum Korrosionsverhalten (mit und ohne überlagerte zyklische Belastung) verschiedener Schweißverbindungen von Blechen aus Magnesiumlegierungen (AZ31, AZ61, AZ91) dargestellt, die mittels Plasma‐, Laserstrahl‐, Elektronenstrahlschweißen im Vakuum und an Atmosphäre geschweißt wurden.

Dabei werden wesentliche Einflussgrößen auf das Korrosionsverhalten von Magnesium‐Schweißverbindungen dargestellt und Maßnahmen, die zur Verbesserung des Korrosionsverhaltens beitragen können, aufgezeigt.
Intraneural perineurioma of the radial nerve visualized by 3.0 Tesla MRI
Authors: Nguyen Doris , Dyck P. James , Daube Jasper R.
Published: April 2007

A progressive radial neuropathy of unknown etiology despite 1.5T magnetic resonance imaging (MRI) and surgical exploration was identified as an intraneural perineurioma by a localized Tinel's sign, an enlarged radial nerve at the spiral groove by 3.0T MRI, and a fascicular biopsy. The distinction between the initial diagnoses of inflammatory, demyelinating polyneuropathy and perineurioma was made by immunohistochemistry and electron microscopy. A slowly progressing, localized mononeuropathy should include perineurioma in the differential diagnosis. Muscle Nerve, 2007
Lower and upper bounds for the degree‐constrained minimum spanning tree problem
Authors: da Cunha Alexandre Salles , Lucena Abilio
Published: April 2007

In this paper, we propose a Lagrangian Non‐Delayed Relax‐and‐Cut algorithm for the Degree‐Constrained Minimum Spanning Tree Problem (DCMSTP). Since degree‐constrained trees are the common vertices of the Spanning Tree and the b‐Matching polytopes, strengthened DCMSTP lower bounds are generated through the use of Blossom Inequalities (BIs). BIs are facet defining for the b‐Matching Polytope and, to the best of our knowledge, have never been used before for DCMSTP. Lagrangian information is also used here, in a Kruskal style algorithm (followed by local search) to obtain valid DCMSTP upper bounds. Whenever optimality could not be proven by Relax‐and‐Cut alone, Lagrangian lower bounds are carried over to a cutting plane algorithm, without the need for solving any separation problem. This is accomplished after identifying, at Relax‐and‐Cut, a small set of attractive Subtour Elimination Constraints and BIs. Computational results, on Euclidean and on random cost DCMSTP instances, indicate that our Relax‐and‐Cut lower bounds either dominate or else are competitive with linear programming and Lagrangian relaxation lower bounds found in the literature. Furthermore, our upper bounds appear competitive with the best in the literature. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 50(1), 55–66 2007
Grading gastrointestinal dysplasia and what to call it when you don't know what it is
Authors: Offerhaus GJ
Published: April 2007

Dysplasia in the gastrointestinal tract is defined as intraepithelial neoplasia (IEN) according to the WHO nomenclature. Neoplastic growth in the gastrointestinal tract evolves through stepwise tumour progression in which consecutive morphological stages are characterized by increasing genetic instability accompanied by specific genetic alterations. Invasive cancer is preceded by non‐invasive precursor stages and the clonal epithelial cell proliferation in these pre‐invasive stages is diagnosed as dysplasia or IEN. Dysplasia is therefore a marker for cancer risk and guides surveillance. Dysplasia is conventionally graded using a two‐tier system and low‐ and high‐grade dysplasia convey different connotations regarding cancer risk. This perspective argues that the critical differential diagnosis is the one between neoplastic and non‐neoplastic epithelial cell proliferations and the relevance of grading dysplasia is questionable. It is furthermore expected that a molecular signature will predict the propensity to invasive carcinoma more accurately than routine histopathology in the near future. Research in this field needs to focus on a combination of biomarkers representing genetic instability, clonal mutations, and genetic clonal divergence. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The α1 subunit of the sodium pump could represent a novel target to combat non‐small cell lung cancers
Authors: Mijatovic T , Roland I , Van Quaquebeke E , Nilsson B , Mathieu A , Van Vynckt F , Darro F , Blanco G , Facchini V , Kiss R
Published: April 2007

With an overall 5 year survival rate as low as 15% for non‐small cell lung cancer (NSCLC), even with surgical intervention and the use of newer molecules in adjuvant chemotherapy, there is an urgent need for new biological targets and associated novel anti‐cancer agents. The present study was undertaken to evaluate the potential of the Na+/K+‐ATPase α1 subunit as a novel target in NSCLC and revealed that α1 expression is markedly higher in a significant proportion of NSCLC clinical samples compared to normal lung tissue. Furthermore, reduction in α1 expression in A549 NSCLC cells by anti‐α1 siRNA resulted in markedly impaired proliferation and migration of these cancer cells. Finally, of three cardenolides investigated, UNBS1450, which is known to bind to Na+/K+‐ATPase and displays potent anti‐tumour activity in vivo in experimental models of human NSCLCs, is the most potent inhibitor of Na+/K+‐ATPase isozymes (α1β1, α2β1 and α3β1), most strikingly of α1β1. This was reflected in the compound's more potent anti‐proliferative activity in all NSCLC cell lines evaluated (A549, Cal‐12T, NCI‐H727 and A427); the first three of which over‐express α1. The marked impairment in A549 NSCLC cell proliferation and migration, and resulting similar morphology following anti‐α1 siRNA or UNBS1450 treatment, was associated with features of abnormal cytokinesis, mediated in the case of UNBS1450 by disorganization of the actin cytoskeleton. Collectively these data strongly suggest that targeting the Na+/K+‐ATPase α1 using specific cardenolides could represent a novel means to combat certain NSCLCs. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Transcriptional silencing of the TMS1/ASC tumour suppressor gene by an epigenetic mechanism in hepatocellular carcinoma cells
Authors: Zhang C , Li H , Zhou G , Zhang Q , Zhang T , Li J , Zhang J , Hou J , Liew CT , Yin D
Published: April 2007

DNA methylation and histone modifications have emerged as key mechanisms in transcriptional regulation. The target of methylation‐induced silencing 1 (TMS1) is a bipartite protein. Recent studies have indicated that methylation‐associated silencing of TMS1 occurs in many cancers. However, whether and how TMS1 is regulated by epigenetic mechanisms in cancers remains unknown. In this study we showed that methylation of the TMS1 promoter occurred in five of six hepatocellular carcinoma (HCC) cell lines. TMS1 expression was reduced in four HCC cell lines and correlated with methylation status. Furthermore, the TMS1 promoter was completely methylated and mRNA expression was undetectable. TMS1 expression could be restored by 5‐aza‐2′‐deoxycitidine (5‐Aza‐dC) (a DNA methyltransferase inhibitor) or trichostatin A (TSA) (a histone deacetylase inhibitor) alone and the promoter methylation was partially reversible. TSA was more efficient than 5‐Aza‐dC in inducing TMS1 expression, and the combination of 5‐Aza‐dC and TSA resulted in markedly synergistic reactivation of the gene and completely reversed promoter methylation. Interestingly, TMS1 promoter methylation‐associated gene silencing was accompanied by histone H3 Lysine 9 (H3K9) hypoacetylation and trimethylation. 5‐Aza‐dC and/or TSA also had some effect on conversion of methylated to acetylated H3K9 in restoring TMS1. This conversion was dynamic at the TMS1 promoter and a decrease in H3K9 trimethylation preceded an increase in H3K9 acetylation after 5‐Aza‐dC and/or TSA treatment. Our results thus suggest that epigenetic inactivation of TMS1 expression is regulated by promoter hypermethylation and H3K9 modifications in a coordinated way. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Enhancement of wood/polyethylene composites via compatibilization and incorporation of organoclay particles
Authors: Zhong Yang , Poloso Tony , Hetzer Max , De Kee Daniel
Published: April 2007

Despite many advantages of wood–polyethylene composites, the shortcomings of this kind of composite include relatively low modulus, low notched impact resistance, relatively large thermal expansion, as well as substantial creep. In this article, in addition to using maleic anhydride grafted polyethylene as compatibilizer, organoclay was introduced into the polyethylene matrix so as to further enhance the thermal and mechanical performance. First, the influence of maleic anhydride grafted polyethylene type and loading on the morphology and properties of wood/HDPE composites was studied. Then, the effects of organoclay loading and of the compounding procedure on the wood/HDPE composites were investigated. The compatibilization was found to result in better polymer impregnation on the wood, reduced linear thermal expansion coefficients, and significantly improved mechanical properties. Incorporation of organoclay further reduced the thermal expansion and elevated the heat deflection temperature. More compatibilizer is needed to maintain the mechanical properties with the presence of clay. POLYM. ENG. SCI., 47:797–803, 2007. © 2007 Society of Plastics Engineers
The role of plug design in determining wall thickness distribution in thermoforming
Authors: Martin P.J. , Duncan P.
Published: April 2007

An experimental investigation has been carried out into the effects of changes in plug design on the wall thickness distribution of thermoformed products. Plugs were machined with a series of geometrical variations and their effects on the process were measured. The overall results show that the plug has a crucial role in controlling the wall thickness distribution in thermoforming. Larger plugs tend to distribute more material to the base of the product, but the introduction of a small sidewall taper, base radius, or a reduction in plug diameter tend to lead to more balanced distributions. However, larger changes in any of the variables tend to destroy these benefits. It has also been demonstrated that the frictional and thermal properties of the plug are important in determining the deformation response of the sheet material. There is a clear evidence of slip in the sheet during plug contact and, although the cooling effect of the plug appears to be minimal, cooling in the highly deformed regions away from the plug appears to be a significant factor. POLYM. ENG. SCI., 47:804–813, 2007. © 2007 Society of Plastics Engineers
Quantitative description of polychloroprene and piperylene–styrene blend films surface morphology
Authors: Jankauskaitė Virginija , Žukienė Kristina , Petraitienė Stasė
Published: April 2007

Surface morphology of polychloroprene (CR) and piperylene–styrene copolymer (PSC) blend films was investigated by atomic force microscopy. The dependence of the blend films surface roughness on PSC content was studied with both fractal and correlation analyses. Gaussian profiles for the height distribution upon blend composition were observed. The topographical images of CR/PSC blends have been characterized by root‐mean‐square roughness, lateral parameter, and fractal dimension values. The analysis showed that quantitative description of surface roughness leads to the differentiation components of polymers blends. Lateral parameter and fractal dimension values of CR films were similar to those of CR/PSC 60/40 wt% blend films. This effect is associated with CR enrichment at the blend film surface. POLYM. ENG. SCI., 47:824–829, 2007. © 2007 Society of Plastics Engineers
Preparation and characterization of rubber‐toughened poly(trimethylene terephthalate)/organoclay nanocomposite
Authors: Mishra Joy K. , Chang Young‐Wook , Choi Nak Sam
Published: April 2007

Rubber‐toughened poly(trimethylene terephthalate) (PTT)–organoclay nanocomposite (RTPTTCN) was prepared by a melt mixing technique. The rubber‐toughened PTT (RTPTT) was made by blending it with ethylene propylene diene terpolymer (EPDM) and with a small amount of maleated EPDM as a compatibilizer. XRD and TEM analysis indicated that the RTPTTCN forms a partially exfoliated nanocomposite. It was observed from SEM analysis that the clay nanoparticles induced a reduction of rubber particle size in the PTT matrix. Tensile and dynamic mechanical analysis indicated that the clay nanoparticles enhance the stiffness of the RTPTT without adversely affecting its toughness. Melt rheological studies revealed that the nanocomposites exhibited strong shear thinning behavior, and a percolated network of the clay particles was formed. It was also observed from DSC that the clay nanoparticles caused an increase in the nonisothermal crystallization temperature of the PTT. POLYM. ENG. SCI., 47:863–870, 2007. © 2007 Society of Plastics Engineers
Finite element analysis for wavelike flow marks in injection molding
Authors: Kang Sung Yong , Kim Seung Mo , Lee Woo Il
Published: April 2007

Wavelike flow marks are a kind of surface defect that can arise during the filling stage of the injection molding process. In this study, we performed a numerical analysis using a finite element method to predict the conditions under which flow marks are generated. To simplify the analysis, a two dimensional flow through a channel between two parallel plates was considered. The viscosity of the polymer melt was modeled by the Cross‐WLF equation. For the finite element analysis, a velocity–pressure formulation was used to simultaneously solve the continuity and momentum equations. The calculation domain for the numerical analysis keeps changing with time due to the advancing melt front. To handle the free surface more accurately, a moving grid method was employed. A numerical mesh was generated at each time step using an automatic mesh generation scheme. An analytical model was developed to correlate the effects of process variables to the flow mark geometry. Results of the numerical analysis were compared with the available experimental data. The estimated geometry of the flow marks were in good qualitative agreement with experimental observations. Parametric studies have been performed to examine the effects of various processing conditions and the material properties on flow mark size. POLYM. ENG. SCI., 47:922–933, 2007. © 2007 Society of Plastics Engineers
High strength polyethylene fibers from high density polyethylene/organoclay composites
Authors: Chantrasakul Siripan , Amornsakchai Taweechai
Published: April 2007

High strength fibers were prepared from high density polyethylene (HDPE)/organically modified montmorillonite (OMMT) composites. X‐ray diffraction study revealed that the composites were of conventional or phase‐separated type. As‐spun composite fibers were found to have higher drawability than as‐spun HDPE fiber. As a result of an increased drawability, fibers with much higher mechanical properties were obtained. The highest modulus and tensile strength obtained in the present study were 38 GPa and 1.7 GPa, respectively. Study of internal morphology suggests that the role of OMMT is to suppress a defect formation and allows the fiber to be drawn to higher draw ratio. Analysis of the mechanical properties of the fibers using a Griffith type relationship suggested that the fibers have much smaller defects and the predicted attainable strength for the fiber is much higher than that previously predicted for melt‐spun and hot drawn fiber. POLYM. ENG. SCI., 47:943–950, 2007. © 2007 Society of Plastics Engineers
Morphology effect on the hydrothermal ageing of a thermoplastic modified epoxy thermoset
Authors: Arribas C. , Sepúlveda L. , Salom C. , Masegosa R.M. , Prolongo M.G.
Published: April 2007

The hydrothermal ageing of an epoxy thermoset modified with different amounts of poly(vinyl acetate), PVAc, was studied by gravimetric analysis, dynamic mechanical thermal analysis, and scanning electron microscopy. Differences in the water uptake process were observed as a function of the PVAc content, these differences were related to the morphology. Samples with nodular morphology, having spheres of thermoplastic dispersed in the epoxy matrix, showed water absorption behavior similar to neat epoxy. However, samples with inverted morphology, in which the thermoplastic formed the continuous phase, were more susceptible to water absorption; they exhibited a continued water uptake that could be described by a two‐stage diffusion model. Samples with inverted morphology showed debonding between phases after hydrothermal ageing. Different dynamic‐mechanical behavior has been found for samples that had epoxy matrix and samples with inverted morphology, both before and after hydrothermal ageing. POLYM. ENG. SCI., 47:960–968, 2007. © 2007 Society of Plastics Engineers
Best starting point to comprehensive process safety education
Authors: Ferjencik Milos
Published: April 2007

Instruction in process safety began at the Faculty of Chemical Technology, University of Pardubice, in the nineties. In 1994, a course named the Safety Engineering was formed. We aimed to equip our students with a theory that would orientate them in safety problems during their professional lives. Similar to analogous courses at other universities, the Safety Engineering course tends to follow basic steps of the quantitative risk analysis (QRA). An accident analysis and two basic notions—a system and a hazard—were selected as starting points of the course.

But after a few years of experience we felt that the Safety Engineering course did not represent exactly what the majority of our students needed. Although the concept of risk analysis represents a fundamental part of any process safety theory, there is another concept that seems to be essential for professionals involved in the process industry—safety management. We started to recognize that an introduction into comprehensive process safety education should be divided into two stages. The safety management and the risk analysis should represent focal points of the first and the second stages, respectively. Two stage arrangement of the process safety course seems to suit needs of our students better than the previous scheme. After the idea of division of the process safety course had arisen, a new starting point for the comprehensive safety education had to be found. An old approach of Kletz's on “learning from accidents” showed itself to be suitable to fulfill this role most naturally. © 2007 American Institute of Chemical Engineers Process Saf Prog 26:195–202, 2007
Nonlinear MPC of kites under varying wind conditions for a new class of large‐scale wind power generators
Authors: Ilzhöfer A. , Houska B. , Diehl M.
Published: April 2007

In this paper we investigate nonlinear model predictive control (NMPC) for control of power generating kites under changing wind conditions. We derive a realistic nonlinear model for a kite and compute energy optimal loops for different wind speeds. We formulate the optimal control problem used by NMPC with an adaptive periodic reference orbit. Under changing wind conditions we use the corresponding energy optimal orbit as reference. To assure that the references do not unnecessarily depend on the wind conditions, we added extra constraints. We solve this NMPC problem numerically with the real‐time iteration scheme using direct multiple shooting. Finally, we present numerical simulations which show how this approach can handle even large disturbances of the wind direction and speed with negligible energy losses. Copyright © 2007 John Wiley & Sons, Ltd.
Constraints on benthic algal response to nutrient addition in oligotrophic mountain rivers
Authors: Bowman Michelle F. , Chambers Patricia A. , Schindler David W.
Published: April 2007

Nutrient availability has long been considered one of the most important factors regulating production of benthic algae in oligotrophic rivers; yet, empirical relationships do not have as wide an application as similar models derived for lentic systems. The aim of this research was to derive empirical relationships between nutrient concentrations and benthic algal abundance and to identify commonalities with other studies to improve our understanding of constraints on algae in oligotrophic rivers. Surveys of physical, chemical and biological attributes of oligotrophic mountain rivers in spring, summer and autumn for 2 years confirmed that small amounts of anthropogenic phosphorus (0.1–5.6 µg/L total phosphorus (TP)) resulted in 4‐ to 30‐fold increases in abundance of benthic algae and benthic macroinvertebrates (BMIs). Algal accrual along a gradient in nutrient availability was not masked by grazing pressure but was positively correlated with abundance of scrapers. Epilithic abundance was highest downstream of anthropogenic nutrient sources in autumn. We concluded that benthic algal abundance in these mountain rivers was weakly correlated with phosphorus availability if light was not limiting but ultimately controlled by temperature and river discharge. Therefore, we recommend more direct measures of nutrient limitation be used to predict changes in ecological integrity at the lower end of the resource gradient. Copyright © 2007 John Wiley & Sons, Ltd.
Bauen mit ETFE‐Folien – Ein Praxisbericht
Authors: Schöne Lutz
Published: April 2007

Um ETFE (Ethylen‐Tetra‐Fluorethylen)‐Folien nachhaltig einen Platz im Materialkanon der Baukonstruktionen zu sichern, wie es für das Glas und die textilen Gewebe in den letzten Jahren gelungen ist, ist eine ständige kritische Bestandsaufnahme notwendig. Dieser Aufsatz soll hierzu einen Beitrag leisten, indem aus allen Bereichen des ingeniösen Umgangs mit Folien berichtet wird. Ausgehend von den Materialeigenschaften wird das Tragverhalten pneumatisch und mechanisch vorgespannter Tragwerke beschrieben, deren Bemessung und Konstruktion angesprochen und sinnvolle zukünftige Entwicklungen diskutiert.
Tensairity‐Patent – Eine pneumatische Tenso‐Struktur
Authors: Pedretti Mauro , Luscher Rudolf
Published: April 2007

Die Parkhauserweiterung für eine zentral gelegene Park‐and‐Rail‐Station in Montreux, Schweiz, durch Luscher Architectes aus Lausanne und mit dem Ingenieurunternehmen Airlight aus Biasca, Schweiz, stellt die erste wichtige architektonische Anwendung des “Tensairity”‐Patents dar. Dabei handelt es sich um eine synergetische Kombination aus Stahlelementen und einem pneumatischen Glasfasergewebe‐Träger, die die Realisierung von neuen, innovativen, sehr leichten und trotzdem sehr widerstandsfähigen konstruktiven Formen ermöglicht.
Inherited Thrombophilia: Key Points for Genetic Counseling
Authors: Varga Elizabeth
Published: April 2007

With the evolution of medical genetics to focus on highly prevalent, multifactorial conditions, it is inevitable that genetic counselors will be called upon to participate in the evaluation and counseling of individuals with inherited thrombophilia. The purpose of this review is to educate the genetic counselor on key issues related to risk assessment and genetic counseling for hereditary thrombophilia. The information contained in this document is derived from an extensive review of the literature, as well as the author's personal expertise. Upon completion of this review, the genetic counselor will be able to: a) describe inherited and acquired risk factors for thrombosis, b) collect and interpret personal and family histories to assess risk related to hereditary thrombophilia, c) discuss the potential advantages and disadvantages of thrombophilia testing, including psychosocial aspects and implications for medical management, and d) identify educational and support resources for patients and families.
Using Adult Learning Theory Concepts to Address Barriers to Cancer Genetic Risk Assessment in the African American Community
Authors: Kendall Jeff , Kendall Colleen , Ali‐Khan Catts Zohra , Radford Cristi , Dasch Kimberly
Published: April 2007

Utilization of cancer genetic risk assessment can be profoundly influenced by an individuals’ knowledge of risk assessment, attitudes regarding illness and healthcare, and affective reactions derived from social norms. Race and ethnicity play a powerful role in the development of an individual's attitudes and should be considered when attempting to understand a person's openness to cancer genetic risk assessment (Lannin et al., 1998). Until recently, however, cancer screening and prevention programs have been primarily based on data from studies conducted with the Caucasian population, yielding data that are not fully applicable to the African American community. In the last several years, research findings regarding African American's knowledge, attitudes, and feelings about genetic counseling and testing have grown (Matthews et al., 2000; Singer et al., 2004; Thompson et al., 2003). However, to the authors’ knowledge, these data have yet to be presented in a manner that both summarizes the barriers that African Americans have reported regarding cancer genetic risk assessment, while at the same time suggesting methods individual genetic counselors can utilize during community presentations to help address these barriers. This article will first summarize previous empirical findings regarding African Americans’ knowledge, attitudes, and feelings about cancer genetic risk assessment. The article will then apply adult learning theory to those findings to provide genetic counselors with practical, theory based techniques to apply toward community based educational programs with African American groups.
Risky Communication: Pitfalls in Counseling About Risk, and How to Avoid Them
Authors: O'Doherty K. , Suthers G. K.
Published: April 2007

A genetic counselor is often faced with the difficult task of conveying a set of complex and highly abstract factors associated with the client's risk of developing a familial disorder. The client is faced with the even more difficult task of making significant health‐related decisions about an event which may or may not eventuate. Although there is a large corpus of research on this topic, much of the knowledge on risk communication is difficult to apply in a practical context. In this paper we draw together some insights on risk communication and decision‐making under conditions of uncertainty, and apply them directly to the problem of communicating familial cancer risk. In particular, we focus on the distinction between individual risk and observed frequencies of adverse events, various framing effects, and contextualizing risk communication. We draw attention to some of the potential pitfalls in counseling about risk and offer avenues for circumventing them.
Kinetics of growth of nanowhiskers (nanowires and nanotubes)
Authors: Avramov Isak
Published: April 2007

The kinetics of nanowhiskers growth is studied theoretically taking into account the adatom diffusion from the surface to the top of needle. An exponential growth with time is expected for the initial stages of the process, when the lengthl of the whisker is smaller than the average diffusion length λ of adatoms. It transforms to linear growth rate forl > λ. The formation of nanotubes with a hollow core dislocation is explained by accounting for the role of the stress in the middle of screw dislocations. When the magnitude of the Burgers vector exceeds a critical value, it is energetically more favorable to remove the highly strained material around the dislocation line and to create a tube with an additional free surface. Additionally, there is an important size effect, due to the small radiusR of the nanowhisker. The interplay, between the contributions from the size effects and from the diffusion, explains why for the very thin nanowhiskers the lengthl is proportional to the radiusR while, otherwise the length is inversely proportional to it, i.e.,l∼1/R.
Urban adolescent stress and hopelessness
Authors: Landis Dana , Gaylord‐Harden Noni K. , Malinowski Sara L. , Grant Kathryn E. , Carleton Russell A. , Ford Rebecca E.
Published: April 2007

This study sought to explore potential mechanisms through which uncontrollable, chronic stressors may lead to hopelessness in low‐income, urban adolescents. In particular, the roles of specific coping strategies as moderators and/or mediators of the association between stressors and hopelessness were examined. Results suggest that chronic, uncontrollable stressors were significantly and positively related to hopelessness in this sample. Active coping, distraction coping, and social‐support‐seeking coping emerged as moderators for males, such that uncontrollable stressors were more highly associated with hopelessness for those boys who reported using more active, distraction, and social‐support‐seeking coping strategies. An analogous moderating effect was found for ruminative coping for girls. Ruminative coping also emerged as a mediator of the relation between uncontrollable stressors and hopelessness for girls.
The relation between self‐concept and social functioning in adolescence
Authors: Ybrandt H.
Published: April 2007

A model of the relation between self‐concept and internalizing and externalizing problem behaviours in adolescence, with the self‐concept influencing problem behaviours (S→IE), was assessed using a sample of 277 Swedish adolescents. The model was tested in a path analysis with data from Youth Self Report (YSR) and Structural Analysis of Social Behaviour (SASB) questionnaires. Consistent with the model, a positive self‐concept was found to be the most important factor for adjustment and for protection against common problem behaviour. A negative self‐concept combined with female gender were risk factors for internalized problems. Self‐control had only a direct effect on externalizing behaviour for boys. Adolescents of 15, 16 years of age had a stronger relationship between a negative self‐concept and externalizing problem behaviour than younger and older adolescents. Internalizing problem behaviours such as anxiety and depression predicted aggressive and delinquent behaviour. These findings highlight the importance of promoting of a positive self‐concept in every adolescent in various psychosocial contexts.
Genetic networks in nonpermissive temperature‐induced cell differentiation of Sertoli TTE3 cells harboring temperature‐sensitive SV40 large T‐antigen
Authors: Tabuchi Yoshiaki , Takasaki Ichiro , Suto Atsumi , Kondo Takashi , Suzuki Yoshihisa , Obinata Masuo
Published: April 2007

To identify the molecular basis by which nonpermissive temperature (NPT) induces cell differentiation in Sertoli TTE3 cells harboring temperature‐sensitive SV40 large T‐antigen, we performed global scale microarray and computational gene network analyses. In TTE3 cells, inactivation of the large T‐antigen by a NPT at 39 °C led to cell differentiation accompanying elevation of transferrin, a marker for differentiation of Sertoli cells, and CDKN1A, a cyclin‐dependent kinase inhibitor. Of the 22,690 probe sets analyzed, NPT down‐regulated 498 probe sets and up‐regulated 432 probe sets by >2.0‐fold. Hierarchical clustering analysis showed six gene clusters. In the down‐regulated cluster I, a significant genetic network including fibronectin 1 was associated with cellular growth and proliferation. In up‐regulated cluster IV, a significant genetic network including CDKN1A was associated with cellular differentiation. The present results provide additional novel insights into the molecular basis of cell differentiation induced by NPT in cells.
Minimizing Genital Tract Trauma and Related Pain Following Spontaneous Vaginal Birth
Authors: Albers Leah L. , Borders Noelle
Published: April 2007

Genital tract trauma is common following vaginal childbirth, and perineal pain is a frequent symptom reported by new mothers. The following techniques and care measures are associated with lower rates of obstetric lacerations and related pain following spontaneous vaginal birth: antenatal perineal massage for nulliparous women, upright or lateral positions for birth, avoidance of Valsalva pushing, delayed pushing with epidural analgesia, avoidance of episiotomy, controlled delivery of the baby's head, use of Dexon (U.S. Surgical; Norwalk, CT) or Vicryl (Ethicon, Inc., Somerville, NJ) suture material, the “Fleming method” for suturing lacerations, and oral or rectal ibuprofen for perineal pain relief after delivery. Further research is warranted to determine the role of prenatal pelvic floor (Kegel) exercises, general exercise, and body mass index in reducing obstetric trauma, and also the role of pelvic floor and general exercise in pelvic floor recovery after childbirth.
Best Practices in Second Stage Labor Care: Maternal Bearing Down and Positioning
Authors: Roberts Joyce , Hanson Lisa
Published: April 2007

Despite evidence of adverse fetal and maternal outcomes from the use of sustained Valsalva bearing down efforts, current second‐stage care practices are still characterized by uniform directions to “push” forcefully upon complete dilatation of the cervix while the woman is in a supine position. Directed pushing might slightly shorten the duration of second stage labor, but can also contribute to deoxygenation of the fetus; cause damage to urinary, pelvic, and perineal structures; and challenge a woman's confidence in her body. Research on the second stage of labor care is reviewed, with a focus on recent literature on maternal bearing down efforts, the “laboring down” approach to care, second‐stage duration, and maternal position. Clinicians can apply the scientific evidence regarding the detrimental effects of sustained Valsalva bearing down efforts and supine positioning by individualizing second stage labor care and supporting women's involuntary bearing down sensations that can serve to guide her behaviors.
Induction of Labor with Homeopathy: A Case Report
Authors: Kistin Susanne J. , Newman Alyssa D.
Published: April 2007

Homeopathic preparations of blue cohosh (Caulophyllum thalictroides) and black cohosh (Actaea racemosa [formerly Cimicifuga racemosa]) have been used around the world for induction and augmentation of labor. There are few clinical studies examining these preparations, and the evidence for their safety and efficacy is largely anecdotal. More research needs to be done to determine whether homeopathy is a potentially viable alternative to oxytocin and prostaglandins for labor induction.
Evidence‐Based Practices for the Fetal to Newborn Transition
Authors: Mercer Judith S. , Erickson‐Owens Debra A. , Graves Barbara , Haley Mary Mumford
Published: April 2007

Many common care practices during labor, birth, and the immediate postpartum period impact the fetal to neonatal transition, including medication used during labor, suctioning protocols, strategies to prevent heat loss, umbilical cord clamping, and use of 100% oxygen for resuscitation. Many of the care practices used to assess and manage a newborn immediately after birth have not proven efficacious. No definitive outcomes have been obtained from studies on maternal analgesia effects on the newborn. Although immediate cord clamping is common practice, recent evidence from large randomized, controlled trials suggests that delayed cord clamping may protect the infant against anemia. Skin‐to‐skin care of the newborn after birth is recommended as the mainstay of newborn thermoregulation and care. Routine suctioning of infants at birth was not been found to be beneficial. Neither amnioinfusion, suctioning of meconium‐stained babies after the birth of the head, nor intubation and suctioning of vigorous infants prevents meconium aspiration syndrome. The use of 100% oxygen at birth to resuscitate a newborn causes increased oxidative stress and does not appear to offer benefits over room air. This review of evidence on newborn care practices reveals that more often than not, less intervention is better. The recommendations support a gentle, physiologic birth and family‐centered care of the newborn.
Closing the Theory–Practice Gap: Intrapartum Midwifery Management of Planned Homebirths
Authors: Vedam Saraswathi , Goff Meredith , Marnin Vicki Nolan
Published: April 2007

In the United States, access to qualified homebirth providers varies by state, city, and community, and consistent, evidence‐based guidelines for intrapartum management at home are not available. This article examines the similarities and differences in midwifery management of the intrapartum, postpartum, and neonatal course between planned homebirths and planned hospital births. Characteristics of qualified attendants, essential medical supplies and equipment, methods for maternal and fetal surveillance, and common intrapartum indications for transfer are discussed. Unique features of management of the healthy woman and baby in the home are described, as well as the process of consultation and/or referral for collaborative or medical management. Current evidence for the management of fetal intolerance of labor, meconium stained amniotic fluid, prolonged labor, postpartum hemorrhage, and the unstable newborn is discussed in the context of homebirth practice. Aspects of homebirth care that require cultural competency and affect the informed consent process are included. Homebirth practice may provide opportunities to increase the congruence between espoused midwifery philosophy and actual practice.
The system of social identities in Tajikistan: Early warning and conflict prevention
Authors: Korostelina Karina
Published: April 2007

The paper aims to explore the interconnections between social identities (ethnic, national, regional and religious) and conflict intentions in Tajikistan. Based on the analysis of the dynamics of identity-based conflicts, the paper emphasizes the importance of an early warning system that centers on social identity and shows what impact such factors as national identity building, religious identity revival, and regional identity reinforcement have on processes of conflict prevention, resolution, and reconciliation. Through the examination of the components of the model, including such factors as intergroup prejudice, outgroup threat, identity salience, ingroup primacy, forms of social identity, and modes of identity meaning, the author shows the main threats to peaceful co-existence in Tajikistan.
HPLC quantification of biogenic amines in cheeses: correlation with PCR-detection of tyramine-producing microorganisms
Authors: Fernández María , Linares Daniel M , del Río Beatriz , Ladero Victor , Alvarez Miguel A
Published: April 2007

The consumption of food and beverages containing high amounts of biogenic amines (BA) can have toxicological effects. BA found in foods and beverages are synthesized by the microbial decarboxylation of certain amino acids. This paper reports the concentrations of BAs in a number of commercial cheeses, as determined by HPLC. The cheeses studied were made from raw and pasteurized milk of different origin, and were subjected to different ripening periods. BA concentrations were lower in short ripening period than in long ripening period cheeses, and higher in cheeses made from raw milk than in those made from pasteurized milk. The highest BA concentrations were recorded in blue cheeses made from raw milk. Tyramine was the most commonly recorded and abundant BA. The presence of tyramine-producing bacteria was determined by PCR, and a good correlation obtained between the results of this method and tyramine detection by HPLC. These methods could be used to complement one another in the detection and quantification of tyramine in cheese prevention of tyramine accumulation in cheese.
In vitro reconstitution of antimicrobial pathogen activity by expressed recombinant bovine lactoferrin N-terminal peptide in Escherichia coli
Authors: Luo Hongxia , Chen Shangwu , Ren Fazheng , Guo Huiyuan , Lin Shaohua , Xu Wentao
Published: April 2007

Recombinant bovine lactoferrin N-terminal polypeptide (rbLF-N) Escherichia coli expression system was constructed and the rbLF-N antimicrobial activity was displayed by enzymatic proteolysis in this study. A 162 bp 5′-terminal fragment of bovine lactoferrin (bLF) gene from bovine liver gDNA was amplified by PCR. The DNA fragment containing exon-2 of the bLF gene was cloned into the expression vector pGEX-4T1 and the glutathione-S-transferase–rbLF-N (GST-rbLF-N) fusion protein was obtained by over-expression in Esch. coli BL21(DE3). After thrombin/pepsin digestion, the rbLF-N was released from the fusion protein. The recombinant peptide was separated and identified by SDS-PAGE, HPLC and LC-MS/MS analysis. A very strong anti-food-born microbial pathogen activity of the rbLF-N peptides was displayed through bio- and kinetic-assays in vitro. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the rbLF-N peptide for bacterial pathogens Staphylococcus aureus, Streptococcus mutans, Esch. coli and Klebsiella pneumoniae were 11·7, 11·7, 11·7, 23·4 μg and 23·4, 11·7, 11·7, 46·4 μg, respectively. This study created a new route for exploring lactoferrin peptide application in food science.
Effect of simulated gastrointestinal digestion on the antihypertensive properties of synthetic β-lactoglobulin peptide sequences
Authors: Hernández-Ledesma Blanca , Miguel Marta , Amigo Lourdes , Aleixandre Maria Amaya , Recio Isidra
Published: April 2007

In this study, the antihypertensive activity in spontaneously hypertensive rats of two peptides isolated from β-lactoglobulin hydrolysates with thermolysin was evaluated. These peptides, with sequences LLF [β-lg f(103–105)] and LQKW [β-lg f(58–61)], showed potent in vitro ACE-inhibitory activity. Two hours after administration, both sequences caused a clear and significant decrease in the blood pressure of these rats. The impact of a simulated gastrointestinal digestion on ACE-inhibitory and antihypertensive activities of these peptides was also studied. The results showed that both fragments were susceptible to proteolytic degradation after incubation with pepsin and Corolase PP®. In addition, their in vitro ACE-inhibitory activity decreased after the simulated digestion. It is likely that fragment LQK was the active end product of the gastrointestinal digestion of peptide LQKW. The fragment LL, observed after digestion of peptide LLF, probably exert its antihypertensive effect through a mechanism of action different than ACE-inhibition.
Long-term evaluation of extracorporeal shock wave lithotripsy in the treatment of salivary stones
Authors: Schmitz S , Zengel P , Alvir I , Andratschke M , Berghaus A , Lang S
Published: April 2007

Extracorporeal shock wave lithotripsy is a rather new therapeutical method in the treatment of sialolithiasis. The objective was to evaluate retrospectively the results of the extracorporeal shock wave lithotripsy therapy performed with a Minilith SL 1 lithotripter on 167 out-patients with symptomatic stones (average size 5.94 mm) of the salivary glands over an observation period of seven years. A successful treatment with total stone disintegration was achieved in 51 (31 per cent) patients. In 92 (55 per cent) patients treatment was partially successful, with disappearance of the symptoms but a sonographically still identifiable stone. Treatment failure occurred in 24 (14 per cent) patients who then underwent surgery. The mean follow-up period was 35.6 months (minimum three, maximum 83), after which 83.2 per cent of the initially successfully treated patients were still free of symptoms.Therefore, extracorporeal shock wave lithotripsy, as a non-invasive treatment alternative with few side effects, is an efficient technique for the therapy of sialolithiasis in selected patients.