bluuebunny/crossref_metadata_2025 huggingface dataset:
Coating of Single DNA Molecules by Genetically Engineered Protein Diblock Copolymers
Authors: Hernandez‐Garcia Armando , Werten Marc W. T. , Stuart Martien Cohen , de Wolf Frits A. , de Vries Renko
Published: August 2012

Coating DNA is an effective way to modulate its physical properties and interactions. Current chemosynthetic polymers form DNA aggregates with random size and shape. In this study, monodisperse protein diblock copolymers are produced at high yield in recombinant yeast. They carry a large hydrophilic colloidal block (≈400 amino acids) linked to a short binding block (≈12 basic amino acids). It is demonstrated that these protein polymers complex single DNA molecules as highly stable nanorods, reminiscent of cylindrical viruses. It is proposed that inter‐ and intramolecular bridging of DNA molecules are prevented completely by the small size of the binding block attached to the large colloidal stability block. These protein diblocks serve as a scaffold that can be tuned for application in DNA‐based nanotechnology.
Activation of Notch Signaling During Ex Vivo Expansion Maintains Donor Muscle Cell Engraftment
Authors: Parker Maura H. , Loretz Carol , Tyler Ashlee E. , Duddy William J. , Hall John K. , Olwin Bradley B. , Bernstein Irwin D. , Storb Rainer , Tapscott Stephen J.
Published: August 2012

Transplantation of myogenic stem cells possesses great potential for long-term repair of dystrophic muscle. However, a single donor muscle biopsy is unlikely to provide enough cells to effectively transplant the muscle mass of a patient affected by muscular dystrophy. Expansion of cells ex vivo using traditional culture techniques significantly reduces engraftment potential. We hypothesized that activation of Notch signaling during ex vivo expansion would maintain donor cell engraftment potential. In this study, we expanded freshly isolated canine muscle-derived cells on tissue culture plates coated with Delta-1ext-IgG to activate Notch signaling or with human IgG as a control. A model of canine-to-murine xenotransplantation was used to quantitatively compare canine muscle cell engraftment and determine whether engrafted donor cells could function as satellite cells in vivo. We show that Delta-1ext-IgG inhibited differentiation of canine muscle-derived cells and increased the level of genes normally expressed in myogenic precursors. Moreover, cells expanded on Delta-1ext-IgG resulted in a significant increase in the number of donor-derived fibers, as compared to cells expanded on human IgG, reaching engraftment levels similar to freshly isolated cells. Importantly, cells expanded on Delta-1ext-IgG engrafted to the recipient satellite cell niche and contributed to further regeneration. A similar strategy of expanding human muscle-derived cells on Notch ligand might facilitate engraftment and muscle regeneration for patients affected with muscular dystrophy.
Statistics.com at the 10‐year mark
Authors: Bruce Peter
Published: August 2012

Statistics.com stands at the intersection of two current trends: (1) an acute shortage of analytic and statistics skills in the labor force and (2) a blossoming of different models for online delivery of higher education. A recent report by the McKinsey Global Institute forecasts a current and continuing shortfall of 140,000–190,000 workers with ‘deep analytical skills’. The skills referred to are in the area of statistics, data mining, and machine learning. Also in the news have been recent ventures by Stanford and other premier universities to offer high‐quality free courses in this area to massive audiences in excess of 100,000. Statistics.com has been building an online program in these subjects since 2002, and now offers 100‐plus online 4‐week courses, relying on an extensive faculty of expert statisticians, and a mixture of traditional and innovative approaches. WIREs Comput Stat 2012, 4:513–517. doi: 10.1002/wics.1225

This article is categorized under:

Applications of Computational Statistics > Organizations and Publications
Bax induces activation of the unfolded protein response by inducing HAC1 mRNA splicing in Saccharomyces cerevisiae
Authors: Çakir Birsen
Published: August 2012

Bax, a multidomain pro‐apoptotic Bcl‐2 protein, localizes to the endoplasmic reticulum (ER), where it regulates ER stress‐induced apoptosis. Adaptation to ER stress depends on the activation of an integrated signal transduction pathway known as the unfolded protein response (UPR). This study examined the death‐inducing activity of Bax and its ability to induce UPR signalling pathways in yeast. We observed that inhibition of global translation in yeast cells expressing Bax correlated with Bax‐induced cell death. Using a lacZ reporter containing several UPR cis‐activating regulatory elements, we also found that Bax directly activated the UPR. Furthermore, this correlated with the splicing of HAC1 mRNA, a gene involved in UPR activation. Bax induced expression of representative UPR target genes such as KAR2, DER1 and GCN4. Finally, we found that Ire1p function is critical for Bax‐induced cell death. Copyright © 2012 John Wiley & Sons, Ltd.
The First Dinuclear Nickel(II) Thiosulfate Obtained From Oxidation of Tri‐tert‐butoxysilanethiol. Contributions to the Chemistry of Silicon‐Sulfur Compounds No. 78[1]
Authors: Pladzyk Agnieszka , Daca Natalia , Ponikiewski Łukasz
Published: August 2012

The title complex, neutral {[Ni2(μ‐S2O3)2(C7H9N)4H2O]C7H8} (1), presents a dinuclear structure with the thiosulfate group acting as a (S, O) chelate and simultaneously as a (S) bridge. The molecular structure was determined by X‐ray crystallography. Complex 1 crystallizes as a hydrogen‐bonded dimer with molecule of toluene solvent in the unit cell. The environment of both central nickel atoms is octahedral with NiN2O2S2 cores. This is the first metal thiosulfate complex isolated as a product of the oxidation of silanethiol. A mechanism of the reaction involving the formation of (RO)3SiSSSi(OR)3 intermediate is proposed with the subsequent cleavage of Si–S bond.
Neue molekulare Indium‐Zinn‐Sauerstoff‐ und Indium‐Zinn‐Natrium‐Sauerstoff‐Chlor‐Cluster
Authors: Veith Michael , Summa Daniela , Huch Volker
Published: August 2012

Abstract. The five‐membered heteroelement cluster THF·Cl2In(OtBu)3Sn reacts with the sodium stannate [Na(OtBu)3Sn]2 to produce either the new oxo‐centered alkoxo cluster ClInO[Sn(OtBu)2]3 (1) (in low yield) or the heteroleptic alkoxo cluster Sn(OtBu)3InCl3Na[Sn(OtBu)2]2 (2). X‐ray diffraction analyses reveal that in compound 1 the polycyclic entity is made of three tin atoms which together with a central oxygen atom form a trigonal, almost planar triangle, perpendicular to which a further indium atom is connected through the oxygen atom. The metal atoms thus are arranged in a Sn3In pyramid, the edges of which are all saturated by bridging tert‐butoxy groups. The indium atom has a further chloride ligand. Compound 2 has two trigonal bipyramids as building blocks which are fused together at a six coordinate indium atom. One of the bipyramids is of the type SnO3In with tert‐butyl groups on the oxygen atoms, while the other has the composition InCl3Na with chlorine atoms connecting the two metals. The sodium atom in 2 has further contacts to two plus one alkoxide groups which are part of a[Sn(OtBu)2]2 dimer disposing of a Sn2O2 central cycle. The hetero element cluster in 2 thus combines three closed entities and its skeleton SnO3InCl3NaO2Sn2O2 consists of three different metallic and two different non‐metallic elements.
Hormonal Contraceptive Use and Discontinuation Because of Dissatisfaction: Differences by Race and Education
Authors: Littlejohn Krystale E.
Published: August 2012

The unintended pregnancy rate in the United States remains high, and there are large race and education differences in unintended pregnancy and fertility. These differences make it important to study race and education differences in contraceptive behavior. Using nationally representative data from the 2002 National Survey of Family Growth, this study examines the effects of race and education on the likelihood that women have ever used particular types of hormonal contraception and have ever discontinued hormonal contraception because of dissatisfaction. The results show that blacks and Latinas were more likely to have used injectable contraceptives (“the shot”) and less likely to have used oral contraceptives (“the pill”) than were white women. Women with less education were more likely than college-educated women to have used the shot but there were no significant education differences in use of the pill. Among women who had ever used hormonal birth control, those with less than a college degree were more likely than college-educated women to discontinue the birth control because of dissatisfaction. However, net of education, this study found no significant racial/ethnic differences in discontinuation. The most commonly stated reason for discontinuation because of dissatisfaction was side effects.
A Child‐inclusive Family Intervention in a Community Adult Mental Health Service
Authors: Cowling Vicki , Garrett Matthew
Published: August 2012

In this paper we describe an intervention that focuses on the needs of children in families where a parent has a mental illness and attends a community adult mental health setting. After a brief outline of the literature, we present a family approach that includes children and young people, their parents and grandparents. Case studies then illustrate the work as a ‘best practice’ for parents who are clients in community adult mental health services.
Mitigating Intergenerational Trauma Within the Parent‐Child Attachment
Authors: Friend Jai
Published: August 2012

Nine‐year‐old Ben was said to hate women. His mother was terrified he'd ‘grow up a woman basher’. This paper describes the work done with Ben and his family at the Hobart Child and Adolescent Mental Health Service. We drew predominantly on three therapeutic modalities: Theraplay, Family Attachment Narrative Therapy and Dyadic Developmental Psychotherapy. Our work enabled Ben's mother to navigate the aftermath of her own trauma history in order to heal Ben's attachment trauma.
Group Cohesion and Homework Adherence in Multi‐Family Group Therapy for Schizophrenia
Authors: Deane Frank P. , Mercer Joanne , Talyarkhan Anahita , Lambert Gordon , Pickard Judy
Published: August 2012

This study examined the relationship between levels of group cohesion, defined as whole group relationships, and between‐session therapeutic homework adherence in a multi‐family group therapy (MFGT) for people with schizophrenia. Participants from 18 consenting families attending MFGT groups completed weekly homework adherence ratings, group cohesion and spontaneous between‐session activity measures. Levels of group cohesion at each session were compared with measures of scheduled and spontaneous homework adherence reported at the next session. It was hypothesised that higher levels of group cohesion would be related to homework adherence and other spontaneous between‐session therapeutic activity completed by group members. Results show higher levels of group cohesion were associated with higher rates of spontaneous between‐session therapeutic activity. However, contrary to expectations no significant relationship between cohesion and scheduled homework completion was found. The implications of the findings for group processes and homework adherence are discussed.
I'm Not a Bad Mother — Stories of Mothering‐on‐the‐Edge
Authors: Snowdon Jenny , Kotzé Elmarie
Published: August 2012

This article is located in the field of custody and day‐to‐day care, with a focus on experiences of mothering where mothers no longer have everyday care of their children. At the time of writing, tens of thousands of mothers live separately from their children in Aotearoa, New Zealand. However, there is a general perception of rarity associated with non‐resident mothers, partly due to their reluctance to speak of loss of custody. In this article, we develop a theoretical discussion around the inside/outside relationships between non‐resident mothers and their children that informs therapeutic practice. We argue that mothers who live apart from their children are situated at the edge or periphery of their children's day‐to‐day lives and experience this as outside the lives of their children. Nevertheless, mothers' stories speak of qualities of (m)othering that have been born of and nurtured by longstanding and long‐term commitment to their children.
Commentary on Cultural Diversity Across the Pacific: The Dominance of Western Theories, Models, Research and Practice in Psychology
Authors: Stewart Lisa
Published: August 2012

The three featured articles in the December 2010 section on cultural diversity across the Pacific address important cultural issues in psychology. Berry (2010) applied these issues to intercultural relations and acculturation, Furnham (2010) to culture shock, and Marsella and Yamada (2010) to psychopathology. The common theme among these articles was the Western-centric dominance of psychology's research, theories, models and practice, in part because of structural discrimination such as ethnocentric curricula, policies and teaching methods within academic institutions. In Aotearoa New Zealand, including mātauranga Māori (Māori knowledge) and kaupapa Māori (Māori philosophy) within curricula for clinical psychology has started to address that Western-centric dominance, but more importantly, resulted in more culturally safe and responsive psychological services being provided to Māori users of those services. The present commentary suggested that including and integrating more cross-cultural and indigenous knowledge into the tertiary curricula of applied psychology fields, such as clinical, industrial-organisational, and coaching psychology would be one way to counter the Western-centric dominance.
ARCHITECT-BUILDERS IN LONDON AND EDINBURGH, c. 1750–1800, AND THE MARKET FOR EXPERTISE
Authors: NENADIC STANA
Published: August 2012

Eighteenth-century architect-builders were a small group, but important for understanding the market strategies of knowledge-based experts in an age of rapid growth in technical information before the creation of modern professions. This article confronts a teleological historiography of emerging professionalization. It is focused on Robert Mylne and several of his contemporaries in Edinburgh and London, including a number of successful London-based Scots who were active as architects, builders, engineers, and surveyors, and self-styled in all these areas when it suited them. It supplies an account of what it took for building experts to establish themselves and flourish in big cities and the ways in which such experts navigated, controlled, and accommodated an environment of unregulated expertise that largely suited contemporary practitioners. Individual, family, and collective market strategies are examined in detail and the final section is a close analysis of the activities of the Architects Club in the 1790s.
RETHINKING THE POLITICS OF WHITE ETHNICITY IN 1970s AMERICA
Authors: MERTON JOE
Published: August 2012

Historians have tended to characterize the ‘white ethnic’ identity politics of the 1970s in the United States as a significant feature of the conservative counterrevolution, especially the rise of populist racial conservatism and its splintering of the Democratic New Deal coalition. Seeking to provide a broader, more representative portrait of white ethnic mobilization, activism, and institutionalization in government, with particular focus on the work of Rev. Geno Baroni, the National Center for Urban Ethnic Affairs, and the Carter administration's Office of Ethnic Affairs, this article challenges that assumption. It posits that the politics of white ethnicity was a far more complex, diverse phenomenon, of appeal to liberals and conservatives in an era of considerable political flux. This reconsideration also reveals that the 1970s were not conservative in the United States, but a watershed decade of uncertainty, volatility, and experimentation, in which ethnic identities and affiliations were reshaped, political norms upended, and new forms of organization and mobilization trialled out, with great significance for today's ‘post-ethnic’ United States. White ethnic politics was of considerable importance to American political development in the late twentieth century, but not in the way usually thought.
REPUBLICANS OF LETTERS, MEMORY POLITICIANS, GLOBAL COLONIALISTS: HISTORIANS IN RECENT HISTORIES OF HISTORIOGRAPHY
Authors: HIRSCHI CASPAR
Published: August 2012

Writing the history of historiography is a tricky business. There is no unbiased way of doing it, and it can serve different goals that at best complement and at worst contradict each other. The genre can seem both suitable to promote one's own academic agenda and to reflect upon one's own ideological constraints, epistemological presumptions, and social aspirations. This article analyses the motivations and methods of recent authors in the field, and it does so principally by focusing on the roles they attribute to historians past and present. To enable comparisons, the article includes works with a national, European and global framework, on early modern and late modern historiography, by intellectual, cultural and post-colonialist historians. A general conclusion will be that while most publications use the genre to pursue academic interests with epistemic arguments, only few try to exploit its potential for critical self-reflexion. As a consequence, they tend to be of limited credibility and originality when it comes to describing historiography's functions and historians' roles. This article does not treat their lack of critical commitment as an isolated phenomenon in a historiographical sub-field, but as a symptom of a larger problem within academic scholarship today. There are, however, exceptions to the rule, and this article will also try to work out their particular strengths.
Shared meals among young adults are associated with better diet quality and predicted by family meal patterns during adolescence
Authors: Larson Nicole , Fulkerson Jayne , Story Mary , Neumark-Sztainer Dianne
Published: August 2012

Objective

To describe shared meal patterns and examine associations with dietary intake among young adults.

Design

Population-based, longitudinal cohort study (Project EAT: Eating and Activity in Teens and Young Adults).

Setting

Participants completed surveys and FFQ in high-school classrooms in Minneapolis/St. Paul, MN, USA in 1998–1999 (mean age = 15·0 years, ‘adolescence’) and follow-up measures online or by mail in 2008–2009 (mean age = 25·3 years, ‘young adulthood’).

Subjects

There were 2052 participants who responded to the 10-year follow-up survey and reported on frequency of having shared meals.

Results

Among young adults, the frequency of shared meals during the past week was as follows: never (9·9 %), one or two times (24·7 %), three to six times (39·1 %) and seven or more times (26·3 %). Having more frequent family meals during adolescence predicted a higher frequency of shared meals in young adulthood above and beyond other relevant sociodemographic factors such as household composition and parental status. Compared with young adults who never had family meals during adolescence, those young adults who reported seven or more family meals per week during adolescence had an average of one additional shared meal per week. Having more frequent shared meals in young adulthood was associated with greater intake of fruit among males and females, and with higher intakes of vegetables, milk products and some key nutrients among females.

Conclusions

Nutrition professionals should encourage families of adolescents to share meals often and establish the tradition of eating together, and work with young adults to ensure that healthy food and beverage choices are offered at mealtimes.
Physiological function of microglia
Authors: Wake Hiroaki , Fields R. Douglas
Published: August 2012

Broad interest in the rapidly advancing field of microglial involvement in forming neural circuits is evident from the fresh findings published in leading journals. This special issue of Neuron Glia Biology contains a special collection of research articles and reviews concerning the new appreciation of microglial function in the normal physiology of the brain that extends beyond their traditionally understood role in pathology.
Evolution of fluid expulsion and concentrated hydrate zones across the southern Hikurangi subduction margin, New Zealand: An analysis from depth migrated seismic data
Authors: Plaza‐Faverola Andreia , Klaeschen Dirk , Barnes Philip , Pecher Ingo , Henrys Stuart , Mountjoy Joshu
Published: August 2012

Identification of methane sources controlling hydrate distribution and concentrations in continental margins remains a major challenge in gas hydrate research. Lack of deep fluid samples and high quality regional scale seismic reflection data may lead to underestimation of the significance of fluid escape from subducting and compacting sediments in the global inventory of methane reaching the hydrate zone, the water column and the atmosphere. The distribution of concentrated hydrate zones in relation to focused fluid flow across the southern Hikurangi subduction margin was investigated using high quality, long offset (10 km streamer), pre‐stack depth migrated multichannel seismic data. Analysis of low P wave velocity zones, bright‐reverse polarity reflections and dim‐amplitude anomalies reveals pathways for gas escape and zones of gas accumulation. The study shows the structural and stratigraphic settings of three main areas of concentrated hydrates: (1) the Opouawe Bank, dominated by focused periodic fluid input along thrust faults sustaining dynamic hydrate concentrations and gas chimneys development; (2) the frontal anticline, with a basal set of proto‐thrusts controlling permeability for fluids from deeply buried and subducted sediments sustaining hydrate concentrations at the crest of the anticline; and (3) the Hikurangi Channel, with buried sand dominated channels hosting significant amounts of gas beneath the base of the hydrate zone. In sand dominated channels gas injection into the hydrate zone favors highly concentrated hydrate accumulations. The evolution of fluid expulsion controlling hydrate formation offshore southern Hikurangi is described in stages during which different methane sources (in situ, buried and thermogenic) have been dominant.
Identification and mapping of dikes with relatively primitive compositions in Thaumasia Planum on Mars: Implications for Tharsis volcanism and the opening of Valles Marineris
Authors: Huang Jun , Edwards Christopher S. , Horgan Briony H. N. , Christensen Philip R. , Kraft Michael D. , Xiao Long
Published: August 2012

We have identified several exposed dikes in Thaumasia Planum Mars using THEMIS, CTX, HiRISE and CRISM data. These dikes extend from tens to ∼100 kilometers in length with average widths of ∼50 m. They display classic ‘en echelon’ patterns while cross‐cutting preexisting geologic features, including extensive wrinkle ridges. Both the dikes and associated fissure eruption products have very blocky morphologies with ∼38% higher thermal inertia than the surrounding regions. The dikes are all enriched in Mg‐rich olivine relative to surrounding terrain, and a subset also contains elevated high‐calcium pyroxene, both of which indicate relatively primitive magma compositions. We propose that these dikes might have served as feeders for the olivine‐enriched flood basalts in this region, and may be derived from the Tharsis plume. These observations provide further evidence that the opening of Valles Marineris was facilitated by tectonic stresses following paths of preferential weakness along preexisting structures such as fractures and faults like those indicated by these dikes.
Orientation matters: Patch anisotropy controls discharge competence and hydroperiod in a patterned peatland
Authors: Kaplan David A. , Paudel Rajendra , Cohen Matthew J. , Jawitz James W.
Published: August 2012

Identifying the mechanisms that drive development of self‐organized patterned landscapes is essential for guiding ecosystem management and restoration. In this work, we modeled flow through real and geostatistically simulated landscapes to test the hypothesis that feedbacks between patch anisotropy and hydroperiod may be sufficient to explain development of the flow‐parallel ridge‐slough mosaic of the Everglades (Florida, USA). Results show patch anisotropy to be a strong predictor of hydroperiod, with ecologically significant increases in flooding duration (>40 days/year) in isotropic landscapes compared with areas of the Everglades with the best‐conserved anisotropic patterning. Notably, hydroperiod differences among landscapes were largest in dry years, suggesting that low flow periods may be most influential in landscape pattern development, contrary to alternative models of pattern formation. This study demonstrates the potential for coupled feedbacks between landscape geometry and hydrology to drive anisotropic pattern formation via inundation frequency without requiring velocity‐driven erosion and redistribution of particulates.
Sensitivity of limiting hurricane intensity to ocean warmth
Authors: Elsner J. B. , Trepanier J. C. , Strazzo S. E. , Jagger T. H.
Published: August 2012

The strongest hurricanes are getting stronger as the oceans heat up especially over the North Atlantic. Sensitivity of hurricane intensity to ocean heating is an important variable for understanding what hurricanes might be like in the future, but reliable estimates are not possible with short time‐series records. Studies using paired values of intensity and sea‐surface temperature (SST) are also limited because most pairs represent hurricanes in an environment less than thermodynamically optimal. Here we overcome these limitations using spatial grids and a model for the limiting hurricane intensity by region and estimate the sensitivity to be 7.9 ± 1.19 m s− K−1 (s.e.) for hurricanes over seas hotter than 25°C across the North Atlantic. Results indicate the potential for stronger hurricanes during the 21st century as oceans continue to warm over this part of the world.
Numerical simulations of local thundercloud field enhancements caused by runaway avalanches seeded by cosmic rays and their role in lightning initiation
Authors: Babich Leonid P. , Bochkov Evgeniĭ I. , Dwyer Joseph R. , Kutsyk Igor M.
Published: August 2012

We investigate the possibility of the production of an ionized domain by the ionization of the atmosphere by cosmic rays amplified by relativistic runaway electron avalanches (RREAs), the polarization of which could lead to the localized boosting of thundercloud fields, triggering the sequence of processes leading to lightning development. For this goal, a 2D numerical model was developed of atmospheric discharges in a self‐consistent electric field allowing for the kinetics of high‐energy REs, low‐energy electrons, and positive and negative ions. The effects are tested for cosmic ray air showers and for the continuous background of low‐energy cosmic radiation. It is shown that lightning cannot be triggered by the joint action of the cosmic ray shower and RREAs. On the contrary, with realistic rates of the cloud charging, the RREAs seeded by low‐energy cosmic rays, produce a plasma domain, at the edges of which the electric field of the cloud is enhanced above the magnitude required for the selfsustained growth of the free electron population, potentially resulting in lightning initiation.
Pulsating aurora beyond the ultra‐low‐frequency range
Authors: Kataoka Ryuho , Miyoshi Yoshizumi , Hampton Donald , Ishii Taro , Kozako Hiroyuki
Published: August 2012

Pulsations, irregularly switching on and off in the brightness with typical durations of an order of 2 to 20 s, are a fundamental characteristic of post‐midnight aurora. Although pulsating aurora is weak compared with those of quiet arcs or breakups, a cutting‐edge sensitive high‐speed camera is now capable of detecting the faint aurora with more than several hundred frames per second. Here we briefly report the fastest‐ever‐observed fluctuation superimposed on a pulsating aurora, which is more than an order of magnitude faster than well‐known 3 ± 1 Hz modulation. The exact generation mechanism remains unknown, and we discuss two different possibilities of the modulation source at the equatorial magnetosphere and at the magnetosphere‐ionosphere coupled region.
Using noble gases to analyze the efficiency of artificial aeration in Lake Hallwil, Switzerland
Authors: Holzner C. P. , Tomonaga Y. , Stöckli A. , Denecke N. , Kipfer R.
Published: August 2012

Eutrophic Lake Hallwil (Switzerland) is equipped with an artificial aeration system to prevent anoxic conditions developing in the deep water during stratification in summer. The aeration system consists of diffusers releasing oxygen‐rich gas containing noble gases into the deep water at the bottom of the lake. The deep water is strongly supersaturated with He, Ne, and Ar, while Kr and Xe are present at concentrations corresponding to their respective atmospheric equilibria. The observed noble gas excesses are related to the operation of the aeration system and to the composition of the injected aeration gas. We show how noble gas data were used successfully to estimate the fraction of the injected aeration gas that effectively remains dissolved in the water body. In particular, as the physical properties of Ar (e.g., atomic mass, solubility, diffusion coefficient) are similar to those of oxygen, the measured noble gas concentrations allow the efficiency of the aeration system to be quantified.
HER3 signalling is regulated through a multitude of redundant mechanisms in HER2-driven tumour cells
Authors: Amin Dhara N. , Sergina Natalia , Lim Lionel , Goga Andrei , Moasser Mark M.
Published: August 2012

HER2 (human epidermal growth factor receptor-2)-amplified tumours are characterized by constitutive signalling via the HER2–HER3 co-receptor complex. Although phosphorylation activity is driven entirely by the HER2 kinase, signal volume generated by the complex is under the control of HER3, and a large capacity to increase its signalling output accounts for the resiliency of the HER2–HER3 tumour driver and accounts for the limited efficacies of anti-cancer drugs designed to target it. In the present paper we describe deeper insights into the dynamic nature of HER3 signalling. Signalling output by HER3 is under several modes of regulation, including transcriptional, post-transcriptional, translational, post-translational and localizational control. These redundant mechanisms can each increase HER3 signalling output and are engaged in various degrees depending on how the HER3/PI3K (phosphoinositide 3-kinase)/Akt/mTOR (mammalian target of rapamycin) signalling network is disturbed. The highly dynamic nature of HER3 expression and signalling, and the plurality of downstream elements and redundant mechanisms that function to ensure HER3 signalling throughput identify HER3 as a major signalling hub in HER2-amplified cancers and a highly resourceful guardian of tumorigenic signalling in these tumours.
Characterization of ML-IAP protein stability and physiological role in vivo
Authors: Varfolomeev Eugene , Moradi Elham , Dynek Jasmin N. , Zha Jiping , Fedorova Anna V. , Deshayes Kurt , Fairbrother Wayne J. , Newton Kim , Le Couter Jennifer , Vucic Domagoj
Published: August 2012

ML-IAP [melanoma IAP (inhibitor of apoptosis)] is an anti-apoptotic protein that is expressed highly in melanomas where it contributes to resistance to apoptotic stimuli. The anti-apoptotic activity and elevated expression of IAP family proteins in many human cancers makes IAP proteins attractive targets for inhibition by cancer therapeutics. Small-molecule IAP antagonists that bind with high affinities to select BIR (baculovirus IAP repeat) domains have been shown to stimulate auto-ubiquitination and rapid proteasomal degradation of c-IAP1 (cellular IAP1) and c-IAP2 (cellular IAP2). In the present paper, we report ML-IAP proteasomal degradation in response to bivalent, but not monovalent, IAP antagonists. This degradation required ML-IAP ubiquitin ligase activity and was independent of c-IAP1 or c-IAP2. Although ML-IAP is best characterized in melanoma cells, we show that ML-IAP expression in normal mammalian tissues is restricted largely to the eye, being most abundant in ciliary body epithelium and retinal pigment epithelium. Surprisingly, given this pattern of expression, gene-targeted mice lacking ML-IAP exhibited normal intraocular pressure as well as normal retinal structure and function. The results of the present study indicate that ML-IAP is dispensable for both normal mouse development and ocular homoeostasis.
Early cell changes and TGFβ pathway alterations in the aortopathy associated with bicuspid aortic valve stenosis
Authors: Forte Amalia , Della Corte Alessandro , Grossi Mario , Bancone Ciro , Provenzano Raffaela , Finicelli Mauro , De Feo Marisa , De Santo Luca S. , Nappi Gianantonio , Cotrufo Maurizio , Galderisi Umberto , Cipollaro Marilena
Published: August 2012

Previous studies on BAV (bicuspid aortic valve)-related aortopathy, whose aetiology is still debated, have focused mainly on severe dilatations. In the present study, we aimed to detect earlier signs of aortopathy. Specimens were collected from the ‘concavity’ (lesser curvature) and the ‘convexity’ (greater curvature) of mildly dilated AAs (ascending aortas; diameter ≤4 cm) with stenotic TAV (tricuspid aortic valve) or BAV and from donor normal aortas. Specimens were submitted to morphometry, immunohistochemistry and differential gene-expression analysis, focusing on SMC (smooth muscle cell) phenotype, remodelling, MF (myofibroblast) differentiation and TGFβ (transforming growth factor β) pathway. Smoothelin and myocardin mRNAs decreased in all the samples from patients, with the exception of those from BAV convexity, where a change in orientation of smoothelin-positive SMCs and an increase of α-SMA (α-smooth muscle actin) mRNA occurred. Dilated aortas from BAV and TAV patients showed both shared and distinct alterations concerning the TGFβ pathway, including an increased TGFβ and TGFβR2 (TGFβ receptor 2) expression in both groups and a decreased TGFβR1 expression in BAV samples only. Despite a decrease of the mRNA coding for the ED-A (extra domain-A) isoform of FN (fibronectin) in the BAV convexity, the onset of the expression of the corresponding protein in the media was observed in dilated aortas, whereas the normal media from donors was negative for this isoform. This discrepancy could be related to modifications in the intima, normally expressing ED-A FN and showing an altered structure in mild aortic dilatations in comparison with donor aorta. Our results suggest that changes in SMC phenotype and, likely, MF differentiation, occur early in the aortopathy associated with valve stenosis. The defective expression of TGFβR1 in BAV might be a constitutive feature, while other changes we reported could be influenced by haemodynamics.
X-ray streak camera cathode development and timing accuracy of the 4ω ultraviolet fiducial system at the National Ignition Facility
Authors: Opachich Y. P. , Palmer N. , Homoelle D. , Hatch B. , Bell P. , Bradley D. , Kalantar D. , Browning D. , Zuegel J. , Landen O.
Published: August 2012

The convergent ablator experiments at the National Ignition Facility (NIF) are designed to measure the peak velocity and remaining ablator mass of an indirectly driven imploding capsule. Such a measurement can be performed using an x-ray source to backlight the capsule and an x-ray streak camera to record the capsule as it implodes. The ultimate goal of this experiment is to achieve an accuracy of 2% in the velocity measurement, which translates to a ±2 ps temporal accuracy over any 300 ps interval for the streak camera. In order to achieve this, a 4ω (263 nm) temporal fiducial system has been implemented for the x-ray streak camera at NIF. Aluminum, titanium, gold, and silver photocathode materials have been tested. Aluminum showed the highest relative quantum efficiency, with five times more peak signal counts per fiducial pulse when compared to Gold. The fiducial pulse data were analyzed to determine the centroiding statistical accuracy for incident laser pulse energies of 1 and 10 nJ, showing an accuracy of ±1.6 ps and ±0.7 ps, respectively.
Snowflake divertor configuration studies in National Spherical Torus Experiment
Authors: Soukhanovskii V. A. , Bell R. E. , Diallo A. , Gerhardt S. , Kaye S. , Kolemen E. , LeBlanc B. P. , McLean A. G. , Menard J. E. , Paul S. F. , Podesta M. , Raman R. , Rognlien T. D. , Roquemore A. L. , Ryutov D. D. , Scotti F. , Umansky M. V. , Battaglia D. , Bell M. G. , Gates D. A. , Kaita R. , Maingi R. , Mueller D. , Sabbagh S. A.
Published: August 2012

Experimental results from NSTX indicate that the snowflake divertor (D. Ryutov, Phys. Plasmas 14, 064502 (2007)) may be a viable solution for outstanding tokamak plasma-material interface issues. Steady-state handling of divertor heat flux and divertor plate erosion remains to be critical issues for ITER and future concept devices based on conventional and spherical tokamak geometry with high power density divertors. Experiments conducted in 4–6 MW NBI-heated H-mode plasmas in NSTX demonstrated that the snowflake divertor is compatible with high-confinement core plasma operation, while being very effective in steady-state divertor heat flux mitigation and impurity reduction. A steady-state snowflake divertor was obtained in recent NSTX experiments for up to 600 ms using three divertor magnetic coils. The high magnetic flux expansion region of the scrape-off layer (SOL) spanning up to 50% of the SOL width λq was partially detached in the snowflake divertor. In the detached zone, the heat flux profile flattened and decreased to 0.5–1 MW/m2 (from 4–7 MW/m2 in the standard divertor) indicative of radiative heating. An up to 50% increase in divertor, Prad in the snowflake divertor was accompanied by broadening of the intrinsic C III and C IV radiation zones, and a nearly order of magnitude increase in divertor high-n Balmer line emission indicative of volumetric recombination onset. Magnetic reconstructions showed that the x-point connection length, divertor plasma-wetted area and divertor volume, all critical parameters for geometric reduction of deposited heat flux, and increased volumetric divertor losses were significantly increased in the snowflake divertor, as expected from theory.
Ehrenfest dynamics is purity non-preserving: A necessary ingredient for decoherence
Authors: Alonso J. L. , Clemente-Gallardo J. , Cuchí J. C. , Echenique P. , Falceto F.
Published: August 2012

We discuss the evolution of purity in mixed quantum/classical approaches to electronic nonadiabatic dynamics in the context of the Ehrenfest model. As it is impossible to exactly determine initial conditions for a realistic system, we choose to work in the statistical Ehrenfest formalism that we introduced in Alonso et al. [J. Phys. A: Math. Theor. 44, 396004 (2011)10.1088/1751-8113/44/39/395004]. From it, we develop a new framework to determine exactly the change in the purity of the quantum subsystem along with the evolution of a statistical Ehrenfest system. In a simple case, we verify how and to which extent Ehrenfest statistical dynamics makes a system with more than one classical trajectory, and an initial quantum pure state become a quantum mixed one. We prove this numerically showing how the evolution of purity depends on time, on the dimension of the quantum state space D, and on the number of classical trajectories N of the initial distribution. The results in this work open new perspectives for studying decoherence with Ehrenfest dynamics.
Invited Article: Polarization “Down Under”: The polarized time-of-flight neutron reflectometer PLATYPUS
Authors: Saerbeck T. , Klose F. , Le Brun A. P. , Füzi J. , Brule A. , Nelson A. , Holt S. A. , James M.
Published: August 2012

This review presents the implementation and full characterization of the polarization equipment of the time-of-flight neutron reflectometer PLATYPUS at the Australian Nuclear Science and Technology Organisation (ANSTO). The functionality and efficiency of individual components are evaluated and found to maintain a high neutron beam polarization with a maximum of 99.3% through polarizing Fe/Si supermirrors. Neutron spin-flippers with efficiencies of 99.7% give full control over the incident and scattered neutron spin direction over the whole wavelength spectrum available in the instrument. The first scientific experiments illustrate data correction mechanisms for finite polarizations and reveal an extraordinarily high reproducibility for measuring magnetic thin film samples. The setup is now fully commissioned and available for users through the neutron beam proposal system of the Bragg Institute at ANSTO.
Application of spatially resolved high resolution crystal spectrometry to inertial confinement fusion plasmas
Authors: Hill K. W. , Bitter M. , Delgado-Aparacio L. , Pablant N. A. , Beiersdorfer P. , Schneider M. , Widmann K. , Sanchez del Rio M. , Zhang L.
Published: August 2012

High resolution (λ/Δλ ∼ 10 000) 1D imaging x-ray spectroscopy using a spherically bent crystal and a 2D hybrid pixel array detector is used world wide for Doppler measurements of ion-temperature and plasma flow-velocity profiles in magnetic confinement fusion plasmas. Meter sized plasmas are diagnosed with cm spatial resolution and 10 ms time resolution. This concept can also be used as a diagnostic of small sources, such as inertial confinement fusion plasmas and targets on x-ray light source beam lines, with spatial resolution of micrometers, as demonstrated by laboratory experiments using a 250-μm 55Fe source, and by ray-tracing calculations. Throughput calculations agree with measurements, and predict detector counts in the range 10−8–10−6 times source x-rays, depending on crystal reflectivity and spectrometer geometry. Results of the lab demonstrations, application of the technique to the National Ignition Facility (NIF), and predictions of performance on NIF will be presented.
Theoretical study of the absorption and nonradiative deactivation of 1-nitronaphthalene in the low-lying singlet and triplet excited states including methanol and ethanol solvent effects
Authors: Orozco-Gonzalez Yoelvis , Coutinho Kaline , Peon Jorge , Canuto Sylvio
Published: August 2012

The photophysics of the 1-nitronaphthalene molecular system, after the absorption transition to the first singlet excited state, is theoretically studied for investigating the ultrafast multiplicity change to the triplet manifold. The consecutive transient absorption spectra experimentally observed in this molecular system are also studied. To identify the electronic states involved in the nonradiative decay, the minimum energy path of the first singlet excited state is obtained using the complete active space self-consistent field//configurational second-order perturbation approach. A near degeneracy region was found between the first singlet and the second triplet excited states with large spin-orbit coupling between them. The intersystem crossing rate was also evaluated. To support the proposed deactivation model the transient absorption spectra observed in the experiments were also considered. For this, computer simulations using sequential quantum mechanic-molecular mechanic methodology was used to consider the solvent effect in the ground and excited states for proper comparison with the experimental results. The absorption transitions from the second triplet excited state in the relaxed geometry permit to describe the transient absorption band experimentally observed around 200 fs after the absorption transition. This indicates that the T2 electronic state is populated through the intersystem crossing presented here. The two transient absorption bands experimentally observed between 2 and 45 ps after the absorption transition are described here as the T1→T3 and T1→T5 transitions, supporting that the intermediate triplet state (T2) decays by internal conversion to T1.
Simulation of steady-state diffusion: Driving force ensured by dual control volumes or local equilibrium Monte Carlo
Authors: Ható Zoltán , Boda Dezső , Kristóf Tamás
Published: August 2012

We provide a systematic comparative analysis of various simulation methods for studying steady-state diffusive transport of molecular systems. The methods differ in two respects: (1) the actual method with which the dynamics of the system is handled can be a direct simulation technique [molecular dynamics (MD) and dynamic Monte Carlo (DMC)] or can be an indirect transport equation [the Nernst-Planck (NP) equation], while (2) the driving force of the steady-state transport can be maintained with control cells on the two sides of the transport region [dual control volume (DCV) technique] or it can be maintained in the whole simulation domain with the local equilibrium Monte Carlo (LEMC) technique, where the space is divided into small subvolumes, different chemical potentials are assigned to each, and grand canonical Monte Carlo simulations are performed for them separately. The various combinations of the transport-methods with the driving-force methods have advantages and disadvantages. The MD+DCV and DMC+DCV methods are widely used to study membrane transport. The LEMC method has been introduced with the NP+LEMC technique, which was proved to be a fast, but somewhat empirical method to study diffusion [D. Boda and D. Gillespie, J. Chem. Theor. Comput. 8, 824 (2012)]10.1021/ct2007988. In this paper, we introduce the DMC+LEMC method and show that the resulting DMC+LEMC technique has the advantage over the DMC+DCV method that it provides better sampling for the flux, while it has the advantage over the NP+LEMC method that it simulates dynamics directly instead of hiding it in an external adjustable parameter, the diffusion coefficient. The information gained from the DMC+LEMC simulation can be used to construct diffusion coefficient profiles for the NP+LEMC calculations, so a simultaneous application of the two methods is advantageous.
Analysis of doping induced wafer bow during GaN:Si growth on sapphire
Authors: Brunner F. , Mogilatenko A. , Knauer A. , Weyers M. , Zettler J.-T.
Published: August 2012

In-situ curvature measurements were employed to quantify stress generation during metalorganic vapor phase epitaxy growth of Si-doped GaN sandwiched between undoped GaN layers. It is shown that the creation of tensile stress in Si-doped GaN is closely linked to the density of threading dislocations in the material. Accompanying characterization by in-situ reflectance measurements and TEM analysis supports the model that the doping induced stress formation is caused by a surface-mediated dislocation climb process. In addition, curvature measurements reveal an unusual partial relaxation in GaN:nid grown atop of highly doped GaN:Si layers. This relaxation is assigned to a notable dislocation annihilation at the upper GaN:Si+/GaN:nid interface found by TEM probably due to the formation of a thin SiNx masking layer.
Thermal conductivity of solid deuterium by the 3ω method
Authors: Gram R. Q. , She A. , Craxton R. S. , Harding D. R.
Published: August 2012

The thermal conductivity of solid D2 is measured by the 3ω method, in which a wire embedded in the medium serves as both a heater and a temperature sensor. Conductivity values are obtained by fitting experimental data with a two-dimensional model that calculates heat flow in both the axial and radial directions as a function of frequency. The model provides the thermal conductivity of D2 from the measurement of the 3ω voltage and published values of specific heat and density of D2 and of the sensor wire, and thermal conductivity values for the sensor wire. Data for D2 gas and liquid are obtained for comparison to solid D2. Conductivity values obtained for solid D2 range from 0.35 ± 0.01 W/(m K) at 18.6 K to 0.75 ± 0.02 W/(m K) at 13.4 K and are the same for normal and ortho D2. These values are acquired at lower temperatures than the 3ω method has previously been used for.