bluuebunny/crossref_metadata_2025 huggingface dataset:
PEX11 proteins attract Mff and hFis1 to coordinate peroxisomal fission
Authors: Koch Johannes , Brocard Cécile
Published: May 2012

Fission of membrane-bound organelles requires membrane remodeling processes to enable and facilitate the assembly of the scission machinery. Proteins of the PEX11 family were shown to act as membrane elongation factors during peroxisome proliferation. Furthermore, through interaction with fission factors these proteins coordinate progression of membrane scission. Using a biochemical approach, we determined the membrane topology of PEX11γ, one of the three human PEX11 proteins. Analysis of mutated PEX11γ versions, which localize to peroxisomes revealed essential domains for membrane elongation including an amphipathic region and regulatory sequences thereof. Through pegylation assays and in vivo studies, we establish that the PEX11γ sequence encloses two membrane anchored domains, which dock an amphipathic region onto the peroxisomal membrane thereby regulating its elongation. The interaction profile of PEX11γ and mutated versions reveals a rearrangement between homo- and heterodimerization and association with fission factors. We also demonstrate the presence of the mitochondrial fission factor Mff on peroxisomes and its interaction with PEX11 proteins. Our data allow for assumptions on a molecular mechanism for the process of peroxisome proliferation in mammalian cells, that i) PEX11γ is required and acts in coordination with at least one of the other PEX11 proteins to protrude the peroxisomal membrane, ii) PEX11 proteins attract both Mff and hFis1 to their site of action and, iii) the concerted interaction of PEX11 proteins provides spatiotemporal control for growth and division of peroxisomes.
Filamin A controls matrix metalloprotease activity and regulates cell invasion in human fibrosarcoma cells.
Authors: Baldassarre Massimiliano , Razinia Ziba , Brahme Nina , Buccione Roberto , Calderwood David A.
Published: May 2012

Filamins are an important family of actin-binding proteins that, in addition to bundling actin filaments, link cell-surface adhesion proteins, signaling receptors, and channels to the actin cytoskeleton, and serve as scaffolds for an array of intracellular signaling proteins. Filamins are known to regulate the actin cytoskeleton, act as mechanosensors that modulate tissue responses to matrix density, control cell motility, and inhibit activation of integrin adhesion receptors. In this study we extend the repertoire of filamin activities to include control of extracellular matrix (ECM) degradation. We show that knockdown of filamin increases matrix metalloprotease activity, induces metalloprotease 2 activation, enhancing the ability of cells to remodel the ECM, and increasing their invasive potential, without significantly altering two-dimensional random cell migration. We further show that within filamin A, the actin-binding domain is necessary, but not sufficient, to suppress ECM degradation seen in filamin A knockdown cells and that dimerization and integrin binding are not required. Filamin mutations are associated with neuronal migration disorders and a range of congenital malformations characterized by skeletal dysplasia and various combinations of cardiac, craniofacial and intestinal anomalies. Furthermore, in breast cancers loss of filamin A has been correlated with increased metastatic potential. Our data suggest that effects on ECM remodeling and cell invasion should be considered when attempting to provide cellular explanations for the physiological and pathological effects of altered filamin expression or filamin mutations.
The phosphatase of regenerating liver 3 (PRL-3) promotes cell migration via Arf-activity dependent stimulation of integrin alpha5 recycling
Authors: Krndija Denis , Münzberg Christin , Maass Ulrike , Hafner Margit , Adler Guido , Kestler Hans A. , Seufferlein Thomas , Oswald Franz , von Wichert Götz
Published: May 2012

The formation of metastasis is one of the most critical problems in oncology. The phosphatase of regenerating liver 3 (PRL-3) is a new target in colorectal cancer mediating metastatic behavior through a promigratory function. However, detailed explanations for this effect have remained elusive. Here we show that PRL-3 is a specific interaction partner of the ADP-ribosylation factor 1 (Arf1). PRL-3 co-localizes with Arf1 in an endosomal compartment and associates with transmembrane proteins such as the transferrin receptor and α5-integrins. PRL-3 interacts with Arf1 through a distinct motif and regulates activation of Arf1. PRL-3-mediated migration depends on expression and activation of Arf1 and is sensitive to treatment with Brefeldin A. We also demonstrate that PRL-3 modulates recycling of α5-integrins and that its phosphatase activity as well as Arf activation and compartmentalization with Arf1 are required for this effect. In summary our data provide a new function for PRL-3 and identify Arf1 as a new PRL-3-dependent mediator of enhanced migration of cancer cells via enhanced recycling of matrix receptors
Novel NEDD1 phosphorylation sites regulate γ-tubulin binding and mitotic spindle assembly
Authors: Gomez-Ferreria Maria Ana , Bashkurov Mikhail , Helbig Andreas O. , Larsen Brett , Pawson Tony , Gingras Anne-Claude , Pelletier Laurence
Published: May 2012

During cell division, microtubules organize a bipolar spindle to drive accurate chromosome segregation to daughter cells. Microtubules are nucleated by the γ-TuRC, a γ-tubulin complex that templates microtubules with 13 protofilaments. Cells lacking γ-TuRC core components do nucleate microtubules,however these polymers fail to form bipolar spindles. NEDD1 is a γ-TuRC interacting protein whose depletion, although not affecting γ-TuRC stability,causes spindle defects similar to the inhibition of its core subunits, including γ-tubulin. NEDD1 is phosphorylated in several residues in mitosis. However, previously identified phosphorylation sites only partially regulate NEDD1 function, as NEDD1 depletion has a much stronger phenotype than mutation of these residues. Using mass spectrometry, we now identified multiple novel phosphorylated sites in the S557–S574 region of NEDD1, close to its γ-tubulin binding domain. Ser to Ala mutations in S565–S574 inhibit the binding of NEDD1 to γ-tubulin and perturb NEDD1 mitotic function yielding microtubule organization defects equivalent to those observed in NEDD1 depleted cells. Interestingly,additional mutations in S557–T560 region restore NEDD1 capacity to bind γ-tubulin and promote bipolar spindle assembly. All together, our data suggest that the interaction NEDD1/γ-tubulin is finely tuned by multiple phosphorylation events in S557–S574 region and is critical for spindle assembly. We also found that CEP192, a centrosomal protein similarly required for spindle formation, associates with NEDD1 and modulates its mitotic phosphorylation. Thus CEP192 may regulate spindle assembly by modulating NEDD1 function.
Association of bromodomain BET proteins with chromatin requires dimerization through the conserved motif B
Authors: Garcia-Gutierrez Pablo , Mundi Maria , Garcia-Dominguez Mario
Published: May 2012

BET (bromodomain and extra terminal domain) family proteins are unique among bromodomain-containing proteins in that they not only associate with acetylated chromatin in interphase, but also remain attached to chromosomes during mitosis. Although the two tandem bromodomains are essential to display this behaviour, they do not suffice. In this work we report that a small conserved domain, motif B, is also required. A deletion mutant of this domain dissociates from mitotic chromosomes. However, inhibition of histone deacetylases alleviates dissociation. We also show that motif-B-dependent association with chromosomes is not restricted to mitosis. Interestingly, our results indicate that motif B constitutes a surface for homo- and hetero-dimerization between BET proteins. Finally, linked to the prominent role BET proteins play in cell proliferation, we report that ectopic expression of the family member Brd2 interferes with neuronal differentiation in P19 cells and in the vertebrate neural tube, probably because of preservation of adequate levels of cyclin A2 and cyclin D1. By contrast, a deletion mutant of motif B fails to perform in this way, highlighting the relevance of this domain for Brd2 function.
Use of audiovisual equipment (SKYPE) for the treatment of hand injuries for remote consultations
Authors: McMullen Emily
Published: May 2012

Introduction

We present this case of a British patient living and working in Africa who used audiovisual (SKYPE) equipment as a treatment option for remote consultation. This was investigated in response to a request by the patient for further postoperative support at a distance after a complex hand surgery procedure.

Methods

Audiovisual (SKYPE) equipment was used by the team in combination with manual therapy as a means of seeking advice, progressing treatment and liaison with a specialist hand therapist and surgeon. The audiovisual equipment was used to complete follow-up of treatment episodes once the patient had returned to Africa.

Results

After five months of audiovisual consultations with the surgeon and clinical specialist hand therapist, the patient reported significant reductions in anxiety regarding the management of his extensive hand injury. The patient's active and passive range of movement and Disabilities of the Arm Shoulder and Hand scores had all improved. The wider multidisciplinary team in his local area was supported by a specialist service and evidence was gathered to support the organizational benefits of using audiovisual equipment.

Conclusion

This case report highlights the potential, clinical and cost benefits of utilizing audiovisual equipment in conjunction with other treatments in the management of remote hand injury patients.
Investigation of the conservative management of mallet injury in Irish acute hospitals
Authors: Minchin Paula , Spirtos Michelle
Published: May 2012

Introduction

Mallet injury is a commonly treated hand injury in acute hospitals. While there is much literature regarding the various treatment options and outcomes, no studies were found that describe the management of this injury across a national health service. This study describes how mallet injury is managed within the acute hospital system in Ireland. An understanding of the current system of service provision is essential for future service development in this area.

Method

Emergency and occupational therapy departments in the 29 acute case-mix hospitals in Ireland were contacted by telephone and postal questionnaire with 47 respondents participating in the study. Descriptive statistics are used to present the results.

Results

Results indicate that accessing acute hospital-based services for the conservative management of mallet injury typically follows a predictable pathway, but can result in delays and disruption to treatment for the patient. There is little evidence of direct referral from the emergency department to the occupational therapist which, when compared with published literature, would represent the most efficient and optimum care pathway for the patient. The choice of splint used by both the emergency and occupational therapy departments differs, but treatment provided is in line with available evidence-based practice.

Conclusions

This preliminary study provides a basis for future service development in the acute management of mallet injury, by describing how treatment is currently provided nationally. Recommendations for further investigation have been made, and the need for audit and outcome measurement has been highlighted. The development of therapy-led services in Ireland is proposed, to improve efficiency and quality of service provision in the conservative management of mallet injury.
Is there a correlation between patient-reported outcome assessed by the Disabilities of the Arm, Shoulder and Hand Questionnaire and total active motion after flexor tendon repair?
Authors: Magnani Paola Errera , Ferreira Aline Miranda , da Silva Rodrigues Eula Katucha , Barbosa Rafael Inácio , Mazzer Nilton , Elui Valéria Meirelles Carril , de Cássia Registro Fonseca Marisa
Published: May 2012

Introduction

Gliding without adhesion is imperative to regain full range of motion after flexor tendon repair. The purpose of this study was to find assessment tools that represent these outcomes and to explore their relationship with hand function.

Methods

Ninety-six flexor tendon injuries in 24 patients were assessed at 12 weeks after flexor tendon repair. Total active motion (TAM) and total passive motion (TPM) were recorded with a goniometer. For patient-reported upper extremity function, the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire was used.

Results

A moderate negative correlation was found between total active motion and DASH score ( r = −0.3809 to −0.5815, P < 0.0001). While TAM and TPM improved over the 12-week period, mean values did not reach those of the uninjured hand. Mean DASH scores improved from 46.05 points at four weeks to 23.5 points at 12 weeks.

Conclusion

Despite early flexor tendon rehabilitation in this sample, after 12 weeks, some degree of dysfunction and loss of active ability for finger flexion still persisted. The DASH appears to be an appropriate outcome tool after flexor tendon repair. The combination of patient-reported questionnaire and measures of impairment such as TAM and TMP give a more comprehensive picture of functional outcome.
When should surgical treatment be considered for premenstrual dysphoric disorder?
Authors: Reid Robert L
Published: May 2012

Premenstrual mood disorders afflict a substantial number of women of reproductive age. Medical treatments provide excellent symptomatic relief to many women but at times a poor therapeutic response or adverse effects attributable to these therapies lead women to seek alternative solutions. Oophorectomy (with concomitant hysterectomy) followed by low-dose estrogen therapy has been shown to be an effective alternative for such cases of menstrual-cycle-related mood disorder.
Epidemiology of premenstrual symptoms and disorders
Authors: Dennerstein Lorraine , Lehert Philippe , Heinemann Klaas
Published: May 2012

The aim of this paper is to review published literature on the types and prevalences of premenstrual disorders and symptoms, and effects of these on activities of daily life and other parameters of burden of illness. The method involved review of the pertinent published literature. Premenstrual disorders vary in prevalence according to the definition or categorization. The most severe disorder being premenstrual dysphoric disorder (PMDD) affects 3–8% of women of reproductive age. This disorder focuses on psychological symptoms whereas global studies show that the most prevalent premenstrual symptoms are physical. Both psychological and physical symptoms affect women's activities of daily life. A considerable burden of illness has been shown to be associated with moderate to severe premenstrual disorders. In conclusion, premenstrual symptoms are a frequent source of concern to women during their reproductive lives and moderate to severe symptoms impact on their quality of lives.
Pathophysiology of premenstrual syndrome and premenstrual dysphoric disorder
Authors: Rapkin Andrea J , Akopians Alin L
Published: May 2012

Premenstrual syndrome (PMS) and premenstrual dysphoric disorder are triggered by hormonal events ensuing after ovulation. The symptoms can begin in the early, mid or late luteal phase and are not associated with defined concentrations of any specific gonadal or non-gonadal hormone. Although evidence for a hormonal abnormality has not been established, the symptoms of the premenstrual disorders are related to the production of progesterone by the ovary. The two best-studied and relevant neurotransmitter systems implicated in the genesis of the symptoms are the GABArgic and the serotonergic systems. Metabolites of progesterone formed by the corpus luteum of the ovary and in the brain bind to a neurosteroid-binding site on the membrane of the gamma-aminobutyric acid (GABA) receptor, changing its configuration, rendering it resistant to further activation and finally decreasing central GABA-mediated inhibition. By a similar mechanism, the progestogens in some hormonal contraceptives are also thought to adversely affect the GABAergic system. The lowering of serotonin can give rise to PMS-like symptoms and serotonergic functioning seems to be deficient by some methods of estimating serotonergic activity in the brain; agents that augment serotonin are efficacious and are as effective even if administered only in the luteal phase. However, similar to the affective disorders, PMS is ultimately not likely to be related to the dysregulation of individual neurotransmitters. Brain imaging studies have begun to shed light on the complex brain circuitry underlying affect and behaviour and may help to explicate the intricate neurophysiological foundation of the syndrome.
On the Existence of Pure Nash Equilibria in Weighted Congestion Games
Authors: Harks Tobias , Klimm Max
Published: May 2012

We study the existence of pure Nash equilibria in weighted congestion games. Let 𝒞 denote a set of cost functions. We say that 𝒞 is consistent if every weighted congestion game with cost functions in 𝒞 possesses a pure Nash equilibrium. Our main contribution is a complete characterization of consistency of continuous cost functions. We prove that a set 𝒞 of continuous functions is consistent for two-player games if and only if 𝒞 contains only monotonic functions and for all nonconstant functions c1, c2 ∈ 𝒞, there are constants a, b ∈ ℝ such that c1(x) = a c2(x) + b for all x ∈ ℝ≥0. For games with at least three players, we prove that 𝒞 is consistent if and only if exactly one of the following cases holds: (a) 𝒞 contains only affine functions; (b) 𝒞 contains only exponential functions such that c(x) = ac eϕx + bc for some ac, bc, ϕ ∈ ℝ, where ac and bc may depend on c, while ϕ must be equal for every c ∈ 𝒞. The latter characterization is even valid for three-player games. Finally, we derive several characterizations of consistency of cost functions for games with restricted strategy spaces, such as weighted network congestion games or weighted congestion games with singleton strategies.
A Gradient Formula for Linear Chance Constraints Under Gaussian Distribution
Authors: Henrion René , Möller Andris
Published: May 2012

We provide an explicit gradient formula for linear chance constraints under a (possibly singular) multivariate Gaussian distribution. This formula allows one to reduce the calculus of gradients to the calculus of values of the same type of chance constraints (in smaller dimension and with different distribution parameters). This is an important aspect for the numerical solution of stochastic optimization problems because existing efficient codes for, e.g., calculating singular Gaussian distributions or regular Gaussian probabilities of polyhedra can be employed to calculate gradients at the same time. Moreover, the precision of gradients can be controlled by that of function values, which is a great advantage over using finite difference approximations. Finally, higher order derivatives are easily derived explicitly. The use of the obtained formula is illustrated for an example of a transportation network with stochastic demands.
A Brief Ascendency: American Labor After 1945
Authors: Salvatore Nick
Published: May 2012

In 1945, American labor unions optimistically expected considerable growth in the coming decades. The New Deal policies continued their influence, and organized labor achieved its highest density rating (35 percent) ever recorded in the United States. By the mid-1950s, however, that figure began to decline, slowly at first and then, after 1970, swiftly. At the close of 2011, it had fallen to 11.8 percent. The cause of this reduction was not simply employer opposition, although that did occur. Rather, the American working class itself underwent a political and sociological sea change, propelled by southern migration of whites and blacks into the industrial North, sharp changes in political attitudes during and after the 1960s, and the economic transformation of the American and global economy that began in the 1970s. Some of these changes were beyond the scope of organized labor’s ability to alter; regarding others, labor proved to be slow, even hesitant, in its response. One consequence was the resurgence of a sharply conservative political vision among American working people that had a powerful impact on national elections and the policy choices followed.
"Broken Windows," Vulnerable Workers, and the Future of Worker Representation
Authors: Weil David
Published: May 2012

The “broken windows” perspective suggests that the erosion of order in a neighborhood leads to elevated fear, retreat from the street, and consequently an environment where more serious crime takes root. I apply the broken windows idea to the workplace. Increasing violations of basic standards in many low-wage workplaces is perceived by workers as the breakdown of laws, making them reluctant to exercise voice in any way, in turn resulting in further erosion of conditions. Efforts to increase union representation are challenging at best under these circumstances. I provide evidence of the decline of complaints by workers over the last decade under the Fair Labor Standards Act as consistent with this story. I then argue that public policy makers and worker advocates should rethink their approach in light of broken windows, focusing on ways to improve collective exercise of basic workplace rights.
Teachers Unions and American Education Reform: The Politics of Blocking
Authors: Moe Terry M.
Published: May 2012

Why has the modern era of American education reform been such a disappointment? Why has a nation so dedicated to improving its schools continually pulled up short, year after year, embracing weak reforms unsuited to the challenge and refusing to throw off the shackles of the past? The answer comes down to simple fundamentals that have long been staples of political science: vested interests, checks and balances. The vested interests in this case are the teachers unions, which are by far the most powerful groups in the politics of education. And their power is magnified by the American system of checks and balances—which, quite by design, creates veto points that make it exceedingly difficult for reformers to get major new legislation passed and correspondingly easy for opponents to block. The teachers unions have been masters of the politics of blocking for the past quarter century. Major reform is threatening to their vested interests in the existing system, and they have used their formidable power—leveraged by checks and balances—to repel, weaken, and render ineffective the efforts of reformers to bring real change. This is the basic story of the modern reform era. The rest is detail.
Do Unions Still Matter in U.S. Elections? Assessing Labor's Political Power and Significance
Authors: Francia Peter L.
Published: May 2012

Popular accounts of the labor movement often suggest that unions are in decline. While there have been sharp declines in union membership as a percentage of the workforce, this study presents evidence that organized labor’s influence in the U.S. elections remains significant. Using data from the American National Election Study and the National Election Pool, the results in this study demonstrate: (1) union households, despite drops in union membership as a percentage of the workforce, have remained a sizeable percentage of the U.S electorate, especially in regions outside of the South; (2) unions boost voter turnout, including among those from traditionally underrepresented demographics; and (3) unions continue to produce a strong Democratic vote in presidential and congressional elections, and boost the Democratic vote among middle-income whites – a critical “swing” constituency. In total, these results suggest that the future strength or weakness of the labor movement is likely to have significant implications for upcoming election outcomes, the party coalitions that ultimately form for future Democratic and Republican candidates, and how representative the electorate will be relative to the population in years to come.
Public Sector Unions Need the Private Sector or Why the Wisconsin Protests Were Not Labor's Lazarus Moment
Authors: Ahlquist John
Published: May 2012

I argue that the extension of collective bargaining rights and formation of public sector labor unions requires the prior existence of these rights among significant sections of the private sector economy. The secular decline in private sector unionization will undermine the political bases of support for public sector unions. I demonstrate that public sector unionism emerged where private sector unions were initially strong. Declining private sector unionism has led to a marked decrease in support for public sector unions. The diminution of their allies in the private sector and the prospect of extended periods of austerity at the state and local level have put public sector unions in a precarious position that Republican governors and legislatures are taking full advantage of. The prospects for renewal in the labor movement are dim.
American Unions in Comparative Perspective
Authors: Wilson Graham K.
Published: May 2012

American unions have been stronger and more politically active than a simple “exceptionalist” perspective would suggest. However, the combination of economic trends evident in other advanced democracies combined with an unsympathetic legal environment has made the decline of private sector unions in the US particularly severe. The growth of unions in the public sector compensates only partially for this decline and creates additional problems for the cause of organized labor in general.
Trade and Political, Military, and Economic Relations
Authors: Massoud Tansa G. , Magee Christopher S.
Published: May 2012

This paper uses an events data set for the post-Cold War era to measure the impact of trade interdependence on three different types of dyadic interactions: political, military, and economic. The paper extends the literature on trade and peace by estimating a model in which trade and interstate interactions are treated as endogenous. We also move beyond the common measure of conflict as the use of force to consider different types and levels of conflict that fall short of war. We find that trade significantly raises net cooperation on political and economic interactions, but trade does not improve net cooperation over military issues. By allowing for mutual causality between cooperation and trade, we show that more cooperation on political and military issues leads to greater trade between countries. Moreover, the impact of overall cooperation on trade is larger than the effect of trade on cooperation. An important lesson from the paper is that the relationship between trade and net cooperation depends on the type of interstate relations being examined. The general findings are supported even after performing a number of robustness checks.
Forced Migration and the Effects of an Integration Policy in Post-WWII Germany
Authors: Falck Oliver , Heblich Stephan , Link Susanne
Published: May 2012

After World War II, about 8 million ethnic Germans — so called expellees — were forced to leave their homelands and settle within the new borders of West Germany. Subsequently, a law (Federal Expellee Law) was introduced to foster their labor market integration. We evaluate this law by comparing the employment situation between expellees and groups of West Germans and GDR refugees over time. We define our comparison groups to uncover even small effects of the law. Still, we find no evidence that the law met its goal to foster the expellees’ labor market integration.
Combined Soil Moisture Meter and Penetrometer
Authors: Feldman Martin , Hah Dooyoung , Hanifa Khalil , Zhang Zhongjie
Published: May 2012

A combined dynamic cone penetrometer and capacitive soil moisture meter is reported. A novel electrode configuration utilizing a shield electrode increases the effective measurement diameter. A readout circuit is implemented that is relatively insensitive to the resistivity of water in soil. The moisture meter electronics fit within a rugged stainless steel pipe with a wall thickness of 1/8 in. and an outer diameter of 0.75 in.
Morphological Characterization of Induced Fracture in Sandstone Using X-ray Computed Tomography Scanning
Authors: Weerakone W. M. S. B , Wong R. C. K. , Kantzas A.
Published: May 2012

Computed tomography (CT) scanning is one of the viable techniques to evaluate apertures of rough walled fractures. However, quantitative evaluation of small fracture apertures using CT data requires use of calibration curves. In this study, the increments of fracture apertures were physically measured using the DEMEC points and the integrated CT numbers across the fracture aperture were calculated from the CT data for development of the calibration chart. This method overcomes the difficulty in fabrication of perfectly smooth rock fractures for the calibration process. It was demonstrated that the calibration curve developed from this method could be used to characterize variable aperture fractures in sandstone within a certain accuracy. In addition, geostatistic tools were used to quantify any anisotropy in fracture aperture. Results reveal that the induced fracture in sandstone displays a high aperture variation and undulation with an anisotropy in aperture distribution.
Automatic Monitoring of Inserting or Retrieving SPT Sampler in Drillhole
Authors: Yang W. W. , Yue Z. Q. , Tham L. G.
Published: May 2012

This paper presents a new device for the automatic monitoring and measurement of drill rod and sampler depth associated with conventional standard penetration testing (SPT). The device consists of a depth tip transducer and a data logger. The transducer can be firmly mounted onto the drillhole casing on the ground surface. The data logger monitors the passing of the sampler and rods through the transducer into the drillhole during rod insertion or retrieval and therefore records the tip depth in real time. The paper presents the results of calibrations and laboratory and field trials. The test results demonstrate that the device can accurately, reliably, and automatically measure the vertical displacement, velocity, and acceleration of rod insertion or retrieval in real time.
Seismic Simulator Testing to Investigate the Cyclic Behavior of Tailings in an Instrumented Rigid Box
Authors: Pépin Nicolas , Aubertin Michel , James Michael , Leclerc Martin
Published: May 2012

Hard rock mine tailings are prone to liquefaction when subjected to the cyclic loading of earthquakes. This response may cause failure of the retaining dams and the release of liquefied tailings. To investigate the geotechnical response of tailings during cyclic loading, an experimental program was conducted using a physical model consisting of an instrumented, rigid box on a large seismic (shaking) simulator. The main objective of the tests performed on tailings was to assess, in a relative manner, their response to cyclic loads, without and with drainage or rigid inclusions (or a combination of both). As the results obtained during such tests can be significantly influenced by the experimental procedure, a rigorous methodology was followed for this experimental program. This paper presents the details of the methodology developed to conduct such tests, as well as some of the results obtained.
Technique for Undrained Triaxial Tests on Unsaturated Soils Using Active Control of Pore-Air Pressure
Authors: Toyota Hirofumi , Takada Susumu
Published: May 2012

Triaxial testing apparatus and procedures for unsaturated soils have become common along with the development of equipment and sensors. Although many drainage conditions are related to the pore-air and pore-water phase, the drained pore-air condition is usually adopted for tests of unsaturated soils. The main reason is that it is difficult to keep the pore-air undrained because the air diffuses easily through a rubber membrane. However, pore-air and pore-water are sometimes not allowed to drain under ground deformation problems. Therefore, undrained conditions in which pore-air and pore-water are not allowed to flow in and out of the soil are achieved in the experiments described herein. First, problems of a conventional triaxial apparatus for unsaturated soils were investigated to produce the undrained conditions. Then, triaxial testing methods under the undrained conditions were developed for overcoming the problems. Finally, the performance of the proposed testing procedure was demonstrated in comparison with results obtained using conventional testing.
Response to “Discussion of Stress Concentration Ratio of Model Stone Columns in Soft Clays” by Fattah, M., Shlash, K., and Al-Waily, M.
Authors: Fattah Mohammed Y.
Published: May 2012

Although there are differences between stone columns and piles by definition, material, mode of failure, and load transfer, the criteria adopted for definition of the failure load are taken from criteria applied to piles. This study makes a short comparison between the behavior of stone columns and piles and discusses the philosophy of selection of the failure criteria of stone columns.
Bond Strength Between Cast-in-Place Ultra-High-Performance- Concrete and Glass Fibre Reinforced Polymer Plates Using Epoxy Bonded Coarse Silica Sand
Authors: Chen Donna , El-Hacha Raafat
Published: May 2012

A significant amount of attention has been directed toward the use of fibre reinforced polymer (FRP) materials in structural applications, particularly as main components in hybrid structural members. As a result, the need for an effective connection mechanism that can maintain full composite action at the interface between adjacent dissimilar materials is critical in order to achieve optimum performance of the hybrid structural members. The objective of this experimental program was to investigate the bond performance between glass fibre reinforced polymer (GFRP) plates and cast-in-place Ultra-High-Performance- Concrete (UHPC) using epoxy bonded coarse silica sand aggregates at the bond interface. Both shear and tension tests were conducted using three different types of epoxy adhesives. The general effectiveness of the connection mechanism at the bond interface as well as the relative performance of each epoxy adhesive used were investigated. Analysis showed that, of the three epoxy adhesives tested, the specimens bonded at the interface between the UHPC and GFRP plates using the moisture tolerant epoxy adhesive intended for bonding of hardened concrete and steel performed the best.
Evaluating the Impact of a Surprise Silicone Additive to a Synthetic Hydrocarbon Lubricant
Authors: Hanks J. T. , Smith D. W. , Stevens C. J. , Winkel R. E.
Published: May 2012

A fractional percentage of a silicone compound was inadvertently introduced in one lot of Rheolube synthetic hydrocarbon grease used in the spin bearings of our momentum control systems. As a result, a decision had to made in a very short time as to whether the grease would meet the performance and life requirements. To accomplish this, a series of tests were undertaken to compare the performance of the subject grease or oil extracted from it to compare to the baseline lubricant. These tests represented each phase of bearing life: vibration, beginning of life, normal operational life, and end of life. Included were two different wettability tests, two different types of elastohydrodynamic lubrication tests and two different types of boundary tests. Acceptance test data of existing units with and without the subject grease were also used to determine how operational performance was affected. In addition to this test data, the Honeywell/Hanks lubricant life model was used to conclude that the subject grease would support our requirements.
Application of Different Nuclides in Retrospective Dosimetry
Authors: Konheiser J. , Mittag S. , Viehrig H. -W. , Gleisberg B.
Published: May 2012

The activities of nuclides produced via the neutron irradiation of reactor pressure vessel (RPV) steel are used to validate respective fluence calculations. Niobium, nickel, and technetium isotopes from RPV trepans of the decommissioned NPP Greifswald (VVER-440) have been analyzed. The activities were determined by TRAMO (Monte-Carlo) fluence calculations, newly applying 640 neutron-energy groups and ENDF/B7 data. Relative to earlier results, fluences up to 20 % higher have been computed, leading to somewhat better agreement between measurement and calculation, particularly in the case of Tc-99.
Analysis of the Notch Effect in Fatigue
Authors: Yanase K. , Endo M.
Published: May 2012

The fatigue-crack propagation at stress concentrations is a topic of significant importance in a number of engineering applications. Further, it is recognized that the fatigue limit of notched components is dictated by the critical condition for either initiation or propagation of a small crack at the root of a notch. Moreover, because most fatigue cracks spend the vast majority of their lives as short cracks, the behavior of such a flaw is of significant importance. In the literature, McEvily and co-workers [McEvily, A. J., Eifler, D., and Macherauch, E., “An analysis of the Fatigue Growth of Short Fatigue Cracks,” Eng. Fract. Mech., Vol. 40, No. 3, 1991, pp. 571–584] developed a modified linear elastic fracture mechanics (LEFM) approach to tackle a number of fatigue problems, including the growth and threshold behavior of small fatigue cracks. In this study, a further extension is presented to deal with notch effects in fatigue. In this method, the elastic–plastic behavior and the crack closure are taken into account, as the major factors responsible for the peculiar behavior of small fatigue cracks emanating from notches. In the present paper, the notch effect in fatigue is systematically investigated by making use of a mechanism-based computational framework. A series of parametric studies demonstrate the predictive capability of the proposed framework. Based on the thorough investigation for notch-fatigue problem, the novelty of present study is illustrated.
Dosimetry of the Decommissioned High-Flux Beam Reactor at Brookhaven Lab
Authors: Hu J. -P. , Reciniello R. N. , Holden N. E.
Published: May 2012

The high-flux beam reactor (HFBR) at the Brookhaven National Laboratory was a heavy water cooled and moderated reactor that achieved criticality on Oct. 31, 1965. It operated at a power level of 40 megawatts. An equipment upgrade in 1982 allowed operations at 60 megawatts. After a 1989 reactor shutdown to reanalyze safety impact of a hypothetical loss of coolant accident, the reactor was restarted in 1991 at 30 megawatts. The HFBR was shut down in December 1996 for routine maintenance and refueling. At that time, a leak of tritiated water was identified by routine sampling of groundwater from wells located adjacent to the reactor’s spent fuel pool. The reactor remained shut down for almost three years for safety and environmental reviews. In November 1999 the United States Department of Energy decided to permanently shut down the HFBR. The decontamination and decommissioning of the HFBR complex, consisting of multiple structures and systems to operate and maintain the reactor, were complete in 2009 after removing and shipping off all the control rod blades. The emptied and cleaned HFBR dome, which still contains the irradiated reactor vessel, is presently under 24/7 surveillance for safety. Detailed dosimetry performed for the HFBR decommissioning during 1996–2009 is described in the paper.
Design and Testing of a Boron Carbide Capsule for Spectral Tailoring in Mixed-Spectrum Reactors
Authors: Greenwood L. R. , Wittman R. , Pierson B. P. , Metz L. A. , Payne R. , Finn E. C. , Friese J. I.
Published: May 2012

A boron carbide capsule has been designed and used for spectral-tailoring experiments at the TRIGA reactor at Washington State University. Irradiations were conducted in pulsed mode and in continuous operation for up to 4 h. A cadmium cover was used to reduce thermal heating. The neutron spectrum calculated with the Monte Carlo N-particle transport code was found to be in good agreement with reactor dosimetry measurements using the STAY’SL computer code. The neutron spectrum resembles that of a fast reactor. The design of a capsule using boron carbide fully enriched in 10B shows that it is possible to produce a neutron spectrum similar to that of 235U fission.
The Power Distribution and Neutron Fluence Measurements and Calculations in the VVER-1000 Mock-Up on the LR-0 Research Reactor
Authors: Košt’ál M. , Juříček V. , Rypar V. , Švadlenková M. , Cvachovec F.
Published: May 2012

The power density distribution in a reactor has significant influence on core structures and pressure vessel mechanical resistance, as well as on the physical characteristics of nuclear fuel. This quantity also has an effect on the leakage neutron and photon field. This issue has become of increasing importance, as it touches on actual questions of the VVER nuclear power plant life time extension. This paper shows the comparison of calculated and experimentally determined pin by pin power distributions. The calculation has been performed with deterministic and Monte Carlo approaches. This quantity is accompanied by the neutron and photon flux density calculation and measurements at different points of the light water zero-power (LR-0) research reactor mock-up core, reactor built-in component (core barrel), and reactor pressure vessel and model. The effect of the different data libraries used for calculation is discussed.
Los Alamos National Laboratory Fission Basis
Authors: Keksis A. L. , Chadwick M. B. , Selby H. D. , Mac Innes M. R. , Barr D. W. , Meade R. A. , Burns C. J. , Wallstrom T. C.
Published: May 2012

This report is an overview of two main publications that provide a comprehensive review of the Los Alamos National Laboratory (LANL) Fission Basis. The first is the experimental paper, “Fission Product Data Measured at Los Alamos for Fission Spectrum and Thermal Neutrons on 239Pu, 235U, 238U,” [Selby, H. D., et al., Nucl. Data Sheets, Vol. 111 2010, pp. 2891–2922] and the second is the theoretical paper, “Fission Product Yields from Fission Spectrum n+239Pu for ENDF/B-VII.1,” [Chadwick, M. B., et al., Nucl. Data Sheets, Vol. 111, 2010, pp. 2923–2964].
The Influence of Headform Circumference and Mass on Alpine Ski Helmet Performance in Laboratory Tests
Authors: Post A. , Gimbel G. , Hoshizaki T. B.
Published: May 2012

With over 200 million individuals participating in alpine skiing and snowboarding worldwide, the number of trauma-related cases and fatalities are on the rise. Traumatic brain injuries (TBI) in particular, are the most common cause of serious injury and death among skiers and snowboarders, with young participants being identified at greater risk for head injury than adults. The purpose of this study is to evaluate the influence of head mass and geometry on the impact performance of alpine ski helmets in laboratory conditions. To accomplish this, extra large helmets were tested on a monorail drop system, with different mass and geometry conditions. The results indicate that the helmets tested with a heavier mass headform yielded lower linear accelerations than the other conditions. The geometry condition indicates that the helmets tested with the smaller headform yield lower accelerations, which implies that materials respond differently depending on the impact footprint. This could indicate that the mass difference and geometry of the headform are an important factor in the performance of helmet liners under laboratory test conditions.
Evaluation of Fracture Toughness Test Data for Multilayer Dissimilar Joint Welds Using a Weibull Stress Model
Authors: Takashima Yasuhito , Ohata Mitsuru , Seto Masaru , Okazaki Yoshitomi , Minami Fumiyoshi
Published: May 2012

Fracture behaviour of welded joints with dissimilar weld metals (WMs) has been investigated in this paper. A low-toughness WM and a high-strength WM with a moderate toughness were layered alternately in the thickness direction. Fracture tests were conducted with 3-point bend (3PB) specimen and tension plate with a through-thickness crack. The 3PB specimen showed a multistage fracture. The first fracture was originated from the low-toughness WM. On the other hand, no multistage fracture occurred in the tension plate, although the low-toughness WM was responsible for brittle fracture initiation in the same manner as in the 3PB specimen. The fracture toughness of the multilayer dissimilar joint was apparently larger than the welded joint made with the low toughness WM only. The weakest-link model has been applied for analyzing those toughness properties of the multilayer dissimilar joint. The estimated fracture toughness by the weakest-link model was not necessarily consistent with the toughness data, which was because of the local stress elevation in the low-toughness WM area close to the high-strength WM. Because of this, a modified Weibull stress model was used to estimate fracture toughness values for the multilayer dissimilar joint WM and to account for an active fracture zone length scale in the multilayer weld joint materials.
Neutron and Gamma Field Investigations in the VVER-1000 Mock-Up Concrete Shielding on the Reactor LR-0
Authors: Zaritsky S. , Egorov A. , Ošmera B. , Mařik M. , Rypar V. , Cvachovec F. , Kolros A.
Published: May 2012

Two sets of neutron and gamma field investigations were carried out in the dismountable model of radiation shielding of the VVER-1000 mock-up on the LR-0 reactor. First, measurements and calculations of the 3He(n,p)T reaction rate and fast neutrons and gamma flux spectra in the operational neutron monitor channel inside a concrete shielding for different shapes and locations of the channel (cylindrical channel in a concrete, channels with collimator in a concrete, cylindrical channel in a graphite). In all cases measurements and calculations of the 3He(n,p)T reaction rate were done with and without an additional moderator-polyethylene insert inside the channel. Second, measurements and calculations of the 3He(n,p)T reaction rate spatial distribution inside a concrete. The 3He(n,p)T reaction rate measurements and calculations were carried out exploring the relative thermal neutron density in the channels and its space distribution in the concrete. Fast neutrons and gamma measurements were carried out with a stilbene (45 × 45 mm) scintillation spectrometer in the energy regions 0.5–10 MeV (neutrons) and 0.2–10 MeV (gammas).
New Experimental Proposal for 235U PFNS Measurement to Answer a Fifty Year Old Question
Authors: Kornilov N. , Massey T. , Grimes S. , Voinov A.
Published: May 2012

The Prompt Fission Neutron Spectrum (PFNS) from 235U(n,f) is very important for various nuclear applications. It has been investigated in different experiments. In spite of ∼50 years of experimental efforts, a continuing conflict exists at thermal neutron energy. Microscopic experimental PFNS cannot describe macroscopic data. In this report we discuss the current status of this problem and suggest a new experiment, which could possibly resolve this problem.