bluuebunny/crossref_metadata_2025 huggingface dataset:
Normative data for uterine size according to age and gravidity and possible role of the classical golden ratio
Authors: Verguts J. , Ameye L. , Bourne T. , Timmerman D.
Published: June 2013

Objectives

To document normal measurements (length, width, anteroposterior (AP) diameter) and proportions of the non‐pregnant uterus according to age and gravidity. We hypothesized that uterine proportions conform to the classical ‘golden ratio’ (1.618).

Methods

This was a retrospective study of ultrasonographic measurements of the length, width and AP diameter of non‐pregnant uteri recorded in our database between 1 January 2000 and 31 July 2012. All patients for whom abnormal findings were reported were excluded and only the first set of measurements for each patient was retained for analysis. Loess (local regression) analysis was performed using age and gravidity as explanatory variables.

Results

Measurements of 5466 non‐pregnant uteri were retrieved for analysis. The mean length was found to increase to 72 mm at the age of 40 and decrease to 42 mm at the age of 80 years. Gravidity was associated with greater uterine length, width and AP diameter. Mean length/width ratio was found to be 1.857 at birth, decreasing to 1.452 at the age of 91 years. At the age of 21 years, the mean ratio was found to be 1.618, i.e. equal to the golden ratio. Increasing gravidity was associated with lower mean length/width ratio.

Conclusions

Uterine size in non‐pregnant women varies in relation to age and gravidity. Mean length/width ratio conformed to the golden ratio at the age of 21, coinciding with peak fertility. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Oncologic Outcomes after Adjuvant Chemotherapy Using FOLFOX in MSI‐H Sporadic Stage III Colon Cancer
Authors: Oh Seung Yeop , Kim Do Yoon , Kim Young Bae , Suh Kwang Wook
Published: June 2013

Background

Little is known of the oncological outcomes after adjuvant FOLFOX chemotherapy in patients with stage III colon cancer showing microsatellite instability high (MSI‐H). In the present study we investigated the prognostic impact of MSI‐H in patients with stage III colon cancer receiving FOLFOX chemotherapy.

Methods

We analyzed the MSI status in 127 patients with stage III colon cancer who underwent curative surgical resection followed by FOLFOX chemotherapy between January 2003 and December 2010. We assessed disease‐free and overall survival (OS) in patients with MSI‐H colon cancer compared with those showing microsatellite instability low or microsatellite stable (MSI‐L/MSS) disease.

Results

Sixteen of the patients (12.6 %) were MSI‐H, and 111 patients (87.4 %) were MSI‐L/MSS. There was no significant difference between patients showing MSI‐H and MSI‐L/MSS except for age (P = 0.030), tumor location (P < 0.001), and differentiation (P = 0.031). Compared with MSI‐L/MSS colon cancer, patients with MSI‐H colon cancer had no significant difference in 5‐year disease‐free and OS (72.2 vs 68.5 %, P = 0.874; 68.1 vs 71.1 %, P = 0.437).

Conclusions

Our study indicates that FOLFOX chemotherapy can be considered to treat stage III colon cancer patients with MSI‐H after surgery, although the study was not randomized and included only a limited number of patients.
Complex‐forming proteins escape the robust regulations of miRNA in human
Authors: Das Jyotirmoy , Chakraborty Sandip , Podder Soumita , Ghosh Tapash Chandra
Published: June 2013

Most proteins carry out their functions by participating in protein complexes. Recently, miRNAs were identified as promising post‐transcriptional regulators that influence a large proportion of genes in higher eukaryotes. We aim to understand the role of miRNAs in the regulation of human proteins that are present in protein complexes. Here, we show that robust regulation by miRNA is absent in human complex‐forming proteins. Moreover, the numbers of miRNA hits cannot direct the evolutionary fate of complex‐forming proteins independently. However, the duplicated complex‐forming proteins having a severe effect on organismal fitness are profoundly targeted by miRNA, probably to reduce the chances of dosage imbalance.
Water Vapour Radiometers for the Australia Telescope Compact Array
Authors: Indermuehle Balthasar T. , Burton Michael G. , Crofts Jonathan
Published: June 2013

We have developed water vapour radiometers (WVRs) for the Australia Telescope Compact Array that are capable of determining signal path-length fluctuations by virtue of measuring small temperature fluctuations in the atmosphere using the 22.2-GHz water vapour line for each of the six antennae. By measuring the line-of-sight variations of the water vapour, the induced path excess and thus the phase delay can be estimated and corrections can then be applied during data reduction. This reduces decorrelation of the source signal. We demonstrate how this recovers the telescope's efficiency as well as how this improves the telescope's ability to use longer baselines at higher frequencies, thereby resulting in higher spatial resolution. A description of the WVR hardware design, their calibration, and water vapour retrieval mechanism is given.
Der Geist und das Reich im Lukanischen Werk: Konkurrenz oder Konvergenz zwischen Pneumatologie und Eschatologie?
Authors: Haacker Klaus B.
Published: June 2013

Since 1950, studies of Luke–Acts have been influenced by a downgrading of eschatology (at least of the expectation that the goal of history would be near). Conzelmann's slogan ‘Die Mitte der Zeit’ (the earthly mission of Jesus as the ‘centre of history’) suggested a long ‘time of the Church’ with the gift(s) of the Holy Spirit as a substitute (and not a foretaste) of the kingdom of God. The present study challenges this influential view of Luke's theology and its impact on definitions of the genre of Acts.
‘Peace and Security’ (1 Thessalonians 5.3): Is It Really a Roman Slogan?
Authors: White Joel R.
Published: June 2013

According to a growing number of scholars, when Paul makes use of the phrase ‘peace and security’ in 1 Thess 5.3, he is alluding to a well-known slogan in Roman propaganda that summed up the benefits of the Pax Romana. While there can be no doubt that ‘peace’ played an important role in Rome's imperial ideology, it is less clear that this was the case for ‘security’, and a review of the evidence presented by the proponents of this view calls into question their conclusion that ‘peace and security’ had the character of a slogan.
Functional health status in children and adolescents after Fontan: comparison of generic and disease-specific assessments
Authors: McCrindle Brian W. , Zak Victor , Pemberton Victoria L. , Lambert Linda M. , Vetter Victoria L. , Lai Wyman W. , Uzark Karen , Margossian Renee , Atz Andrew M. , Cook Amanda , Newburger Jane W.
Published: June 2013

Purpose: The aim of this study was to compare associations between generic versus disease-specific functional health status assessments and patient and clinical characteristics for patients with severe congenital heart disease. Methods: This was a cross-sectional observational study involving 325 single ventricle patients, aged 10–18 years, after Fontan procedure. Enrolled patients underwent a medical history review, laboratory testing, and assessment of the functional health status by completion of the generic Child Report Child Health Questionnaire and the disease-specific Congenital Heart Adolescent and Teenage questionnaire. Correlated conceptually equivalent domains from both questionnaires were identified and their associations with patient and clinical variables were compared. Results: From the generic assessment, patients perceived marginally lower physical functioning (p = 0.05) but greater freedom from bodily pain compared with a normal population (p < 0.001). The equivalent physical functioning/limitations domain of the generic instrument, compared with the disease-specific instrument, had similar associations (higher multi-variable model R2) with medical history variables (R2 = 0.14 versus R2 = 0.12, respectively) and stronger associations with exercise testing variables (R2 = 0.22 versus R2 = 0.06). Similarly, the corresponding freedom from bodily pain/symptoms domains from both questionnaires showed a greater association for the generic instrument with medical history variables (R2 = 0.15 versus R2 = 0.09, respectively) and non-cardiac conditions (R2 = 0.13 versus R2 = 0.06). The associations of each questionnaire with echocardiographic results, cardiac magnetic resonance imaging results, and serum brain natriuretic peptide levels were uniformly weak (R2 range <0.01 to 0.04). Conclusions: Assessment of the physical functional health status using generic and disease-specific instruments yields few differences with regard to associations between conceptually similar domains and patient and clinical characteristics for adolescents after Fontan procedure.
Risk Factors for Injuries in Landslide- and Flood-Affected Populations in Uganda
Authors: Agrawal Shreya , Gopalakrishnan Tisha , Gorokhovich Yuri , Doocy Shannon
Published: June 2013

Introduction

The frequency of occurrence of natural disasters has increased over the past several decades, which necessitates a better understanding of human vulnerability, particularly in low-resource settings. This paper assesses risk factors for injury in the March 2010 floods and landslides in Eastern Uganda, and compares the effects of location, injury type, and severity.

Methods

A stratified cluster survey of the disaster-affected populations was conducted five months after onset of the disasters. Probability proportional to size sampling was used to sample 800 households, including 400 affected by floods in Butaleja District and 400 affected by landslides in Bududa District.

Results

Flood- and landslide-affected populations were surveyed in July 2010 using a stratified cluster design. The odds of injury were 65% higher in the flood-affected groups than the landslide-affected groups in a logistic regression (OR = 0.35; 95% CI, 0.24-0.52; P < .001). The injury rate was greater in individuals under 42 years of age, and location of injury was a contributing factor. More people were injured in the flood-affected population as compared with the landslide-affected population, and injuries were more severe.

Conclusions

This study illustrates differences between populations injured by flood and landslide disasters that occurred simultaneously in Eastern Uganda in 2010. In areas where landslides are prone to occur due to massive rainfalls or floods, preventative measures, such as early warning systems and evacuation, are more likely to increase the likelihood of people surviving, while for areas with massive floods, immediate and effective medical attention can save lives and improve injury outcomes.

AgrawalS, GopalakrishnanT, GorokhovichY, DoocyS. Risk factors for injuries in landslide- and flood-affected populations in Uganda. Prehosp Disast Med. 2013;28(4):1-9.
Introduction: what are mergers and can they be reversed?
Authors: MAGUIRE WARREN , CLARK LYNN , WATSON KEVIN
Published: June 2013

In his foundational book on accents of English, Wells (1982: 374–5) describes the apparent merger of the vowels in thenurseandnorthlexical sets in Tyneside English (‘Geordie’) as follows: ‘In the broadest Geordie the lexical setnurseis merged withnorth, /ɔː/:work[wɔːk],first[fɔːst],shirt[ʃɔːt] (=short).’
ON THE DEFINITION OF GRAPH INDEX
Authors: STOIMENOW A.
Published: June 2013

This paper discusses a flaw in Murasugi–Przytycki’s Memoir ‘An index of a graph with applications to knot theory’ [Mem. Amer. Math. Soc. 106 (1993)]. We point out and partly fix a gap occurring in the proof of Murasugi–Przytycki’s braid index inequalities involving the graph index. We explain why their notion of index fails to precisely reflect the reduction of Seifert circles by their diagram move, and redefine the index to account for that discrepancy.
THE AMBIVALENT GIFT
Authors: Jones Jane
Published: June 2013

The question of who holds responsibility for racial uplift within African American communities is an enduring one. This paper investigates the understanding of racial obligation on the part of Black elite philanthropic donors. Through in-depth interviews with twenty elite donors, I investigate whether African American elite donors use philanthropic activity to realize their racial obligations by supporting Black nonprofit organizations and charitable causes that directly benefit Black people. I find that Black donors are deeply ambivalent about their position as members of a racial group that is marginalized while they are individually privileged because of their class position. They attempt to reconcile this ambivalence through their philanthropic giving. Donors at times embrace the importance of their racial identity as a principle that organizes their giving practices, but in other instances the very same donors reject race as a factor orienting how they think about their charity. Donors express this inconsistency through three different giving strategies. First, Black donors advocate for what they consider to be Black causes within mainstream organizations—initiatives they believe will directly and positively benefit Black people. Second, while they may support Black nonprofit organizations, they qualify the types of Black organizations worthy of their support. Third, donors reject race as an orienting principle altogether. Indeed, while there are few distinctive patterns among Black elite donors, no matter how they give they do so with an eye towards maintaining a mainstream sensibility that emphasizes integration, efficiency, and success. It is perhaps the diversity of contradictory strategies that poses the most fundamental challenge to the notion of community that permeates discussions of race and responsibility. I conclude by arguing that the ability to define when and how race matters to them is a particular privilege of the Black elite.
BIRTHRIGHT CITIZENSHIP AND THE RACIAL CONTRACT
Authors: Menzel Annie
Published: June 2013

Since 1981, there has been a sea change in longstanding policies ofjus soli, or birthright citizenship, reinforcing the global divide between affluent spaces of whiteness and impoverished spaces of nonwhiteness. I argue that these moves highlight the global system of citizenship as an increasingly consequential aspect of what Charles Mills terms the Racial Contract: the set of agreements, historically explicit and currently tacit, that divides the earth's peoples into full persons—Whites—and subpersons—nonwhites—such that the latter are constitutive outsiders to the political, moral, and epistemological norms that structure the White social world. Mills posits that the present phase of the Racial Contract disconnects present geographies of inequality from the violent history of the earlier phase that brought them into being, thereby moving them outside the realm of redress. I focus on formal citizenship as a central locus of such erasure, using the figuration of the undocumented mother in the controversy over U.S. birthright citizenship as a case study. I argue that the global regime of citizenship perpetuates White supremacy in two ways: first, through a Westphalian map of citizenship, and second, through gendered and raced neoliberal norms of citizenship. The alchemy between these two rationalities both entrenches and hides the violence of the Racial Contract. Building upon Mills' standpoint epistemology, I analyze arguments from both sides of a 1995 congressional hearing on birthright citizenship. I argue that the arguments opposing birthright citizenship exhibit what can be thought of as aWhite epistemology of citizenship, which relies upon a profound amnesia about the exclusionary and violent history of the global regime of citizenship.
THE “NINE LIVES” OF OPPOSITIONAL CULTURE?
Authors: Lewis Amanda E.
Published: June 2013

Some of the more influential research on race and education published in the last few decades comes from the work of John Ogbu and Signithia Fordham (Fordham 1988; Fordham and Ogbu, 1986; Ogbu 1978, 1987, 1991, 2003). In Ogbu's writing about the oppositional culture hypothesis, he argued that Black students frame their relationship to schooling through the lens of their historic marginalization in the United States. Out of their understanding of their systematic disenfranchisement, Ogbu suggested that “they not only generate theories [that] contradict dominant notions of status attainment and produce disillusionment about the instrumental value of school; but develop substantial distrust for school and its agents which then suppresses commitment to school norms” (Lewis et al., 2008, p. 259). Together, Fordham and Ogbu (1986) expanded on these ideas in their article on the “acting White” hypothesis suggesting that students not only disengage from school themselves, they also put pressure on their Black peers not to work hard in school lest they be accused of “acting White.” Together these two interconnected theories have gained substantial notoriety and have become part of the general commonsense about why Black students are not doing better in school—“the problem,” it is believed, is the academic disengagement or “oppositional culture” of African American students.
RACIAL ‘BOUNDARY-POLICING’
Authors: Osuji Chinyere K.
Published: June 2013

As people who cross racial boundaries in the family formation process, the experiences of interracial couples can actually reveal the nature of racial boundaries within and across societies. I draw on in-depth qualitative interviews with eighty-seven respondents in interracial Black and White couples in Los Angeles and Rio de Janeiro to compare perceptions of public stigmatization by outsiders, a term I call “boundary-policing.” I find that couples in Los Angeles perceive gendered, Black individuals as perpetrators of this boundary-policing. In Rio de Janeiro, couples perceive regionalized and classed, White perpetrators. These findings suggest that in the United States and Brazil, racial boundaries are intertwined with class and gender boundaries to shape negotiation of boundary-policing in the two contexts. This analysis builds on previous studies of ethnoracial boundaries by showing how individuals reinforce and negotiate them through interpersonal relations. It demonstrates the similarities and differences in the negotiation and reinforcement of racial boundaries in the two sites.
Comment on “The problem of deficiency indices for discrete Schrödinger operators on locally finite graphs” [J. Math. Phys. 52, 063512 (2011)]
Authors: Golénia Sylvain , Schumacher Christoph
Published: June 2013

In this comment we answer negatively to our conjecture concerning the deficiency indices. More precisely, given any non-negative integer n, there is locally finite graph on which the adjacency matrix has deficiency indices (n, n).
Modelling the metal-on-top effect for Pd clusters on the MgO{100} substrate
Authors: Atanasov Ivailo , Barcaro Giovanni , Negreiros Fabio R. , Fortunelli Alessandro , Johnston Roy L.
Published: June 2013

We introduce a novel empirical model for the adhesion of Pd clusters on the MgO{100} substrate. The new model corrects the known bias of previous models toward structures with large interfaces with the substrate due to the failure to account for the so-called “metal-on-top” effect, i.e., the enhancement of the adhesion due to the presence of other metal atoms on top of those which are directly in contact with the substrate. The new model is parametrised using density-functional theory calculations on MgO-supported Pd clusters with sizes up to 80 atoms. The proposed potential is continuous with respect to spatial coordinates and can therefore be used directly in molecular dynamics simulations.
Orientation of cholesterol in hybrid bilayer membranes calculated from the phases of methyl resonances in sum frequency generation spectra
Authors: Kett P. J. N. , Casford M. T. L. , Davies P. B.
Published: June 2013

The phases of Sum Frequency Generation (SFG) vibrational resonances recorded from thin films on metal surfaces provide information on the orientation and tilt angles of the functional groups of molecules in the film. SFG spectra have been simulated for monolayer films in which the adsorbed molecule has an unequal number of methyl groups oriented in two different directions. The phases, on resonance, of the methyl symmetric (r+) and asymmetric (r−) resonances are determined as a function of the two methyl group tilt angles and the fraction of groups pointing in that particular direction. The results are first presented as two-dimensional projection plots for the r+ and r− resonances and then combined to show the tilt angles of the methyl groups, and fraction of methyl groups in that orientation, for which both resonances are in phase or out of phase with one another. Mathematical expressions have been calculated to identify the precise boundary conditions for when the phases of the r+ and r− resonances change. The results of these simulations are compared to the phases of the methyl resonances in experimental SFG spectra of d7-cholesterol in a hybrid bilayer membrane.
Coarsening kinetics in demixed lead borate melts
Authors: Dittmar A. , Bornhöft H. , Deubener J.
Published: June 2013

Lead borate melts have been demixed at temperatures in range from 723 to 773 K for times up to 20 h. It is found that increasing time and temperature lead to characteristic changes in the size distribution of boron trioxide drops in the lead-rich glassy matrix (<80.7 mol. % B2O3). The increase of the mean drop size with annealing time followed the cube root time dependence of diffusion controlled coarsening. The diffusivity of the coarsening process was determined using liquid-liquid interfacial energy associated with drop deformation in glass specimens subjected to uniaxial compression. Diffusion coefficients of coarsening were found to match with those of 207Pb and 18O tracer ions in the lead borate system but differ up to four orders of magnitude from the Eyring diffusivity and by a factor of ≈7 from the activation energy of viscous flow. The results indicate that coarsening in demixed lead borate melts is most likely controlled by the short range dynamics of the interaction between lead cations and BO4 units, which are decoupled from the time scales of cooperative rearrangements of the glassy network at T < 1.1 Tg.
2 μm laterally coupled distributed-feedback GaSb-based metamorphic laser grown on a GaAs substrate
Authors: Apiratikul P. , He L. , Richardson C. J. K.
Published: June 2013

We report a type-I GaSb-based laterally coupled distributed-feedback (DFB) laser grown on a GaAs substrate operating continuous wave at room temperature. The laser structure was designed to operate near a wavelength of 2 μm and was grown metamorphically with solid-source molecular beam epitaxy. The device was fabricated using a 6th-order deep etch grating structure as part of the sidewalls of the narrow ridge waveguide. The DFB laser emits total output power of up to 40 mW in a single longitudinal mode operation at a heat-sink temperature of 20 °C.
Instrument for gas permeation measurements at high pressure and high temperature
Authors: Perez Edson V. , Balkus Kenneth J. , Ferraris John P. , Musselman Inga H.
Published: June 2013

An instrument was built for the permeation testing of flat polymer membranes under pressures up to 3.0 MPa and temperatures up to 300 °C. The high pressure, high temperature cell uses aluminum tape and a graphite gasket to minimize the leak from the high pressure side to the low pressure side, making possible the permeability measurements of slow diffusing gases such as N2. A computer program developed on a LabVIEW platform fully controls the instrument and data acquisition. It incorporates algorithms to automatically adjust the downstream volume, repressurize the upstream volume, vent the downstream volume to prevent over pressurization, and change the temperature of the permeation cell. The percent relative standard deviation of the permeability measurements was <5.5%. Flat membranes of VTEC PI-1388 polymer were tested from 0.3 to 3.0 MPa and from 35 to 300 °C. The permeabilities and fluxes of H2, CO2, and N2 increased with increasing temperature, while the H2/CO2 ideal selectivity remained unchanged. The major contribution to increased flux arose from increments in temperature rather than pressure.
A compact, all solid-state LC high voltage generator
Authors: Fan Xuliang , Liu Jinliang
Published: June 2013

LC generator is widely applied in the field of high voltage generation technology. A compact and all solid-state LC high voltage generator based on saturable pulse transformer is proposed in this paper. First, working principle of the generator is presented. Theoretical analysis and circuit simulation are used to verify the design of the generator. Experimental studies of the proposed LC generator with two-stage main energy storage capacitors are carried out. And the results show that the proposed LC generator operates as expected. When the isolation inductance is 27 μH, the output voltage is 1.9 times larger than the charging voltage on single capacitor. The multiplication of voltages is achieved. On the condition that the primary energy storage capacitor is charged to 857 V, the output voltage of the generator can reach to 59.5 kV. The step-up ratio is nearly 69. When self breakdown gas gap switch is used as main switch, the rise time of the voltage pulse on load resistor is 8.7 ns. It means that the series-wound inductance in the discharging circuit is very small in this system. This generator can be employed in two different applications.
Strain-induced structure transformations on Si(111) and Ge(111) surfaces: A combined density-functional and scanning tunneling microscopy study
Authors: Zhachuk R. , Teys S. , Coutinho J.
Published: June 2013

Si(111) and Ge(111) surface formation energies were calculated using density functional theory for various biaxial strain states ranging from −0.04 to 0.04, and for a wide set of experimentally observed surface reconstructions: 3 × 3, 5 × 5, 7 × 7 dimer-adatom-stacking fault reconstructions and c(2 × 8), 2 × 2, and \documentclass[12pt]{minimal}\begin{document}$\sqrt{3}\times \sqrt{3}$\end{document}3×3 adatoms based surfaces. The calculations are compared with scanning tunneling microscopy data obtained on stepped Si(111) surfaces and on Ge islands grown on a Si(111) substrate. It is shown that the surface structure transformations observed in these strained systems are accounted for by a phase diagram that relates the equilibrium surface structure to the applied strain. The calculated formation energy of the unstrained Si(111)-9 × 9 dimer-adatom-stacking fault surface is reported for the first time and it is higher than corresponding energies of Si(111)-5 × 5 and Si(111)-7 × 7 dimer-adatom-stacking fault surfaces as expected. We predict that the Si(111) surface should adopt a c(2 × 8) reconstruction when tensile strain is above 0.03.
Energy offset between valence band anti-crossing and optical polarization switching in semipolar InGaN quantum wells
Authors: Schade L. , Schwarz U. T.
Published: June 2013

Light emitted from a semipolar InGaN quantum well parallel to the surface normal is partially polarized, in contrast to the unpolarized emission of c-plane quantum wells. Anti-crossing of the two topmost valence bands causes polarization switching between ordinary and extraordinary polarizations for certain semipolar quantum well orientations with increasing indium content. Two properties of the two measured spectra, their polarization resolved but spectrally integrated intensity and their measured energy splitting, are associated with anti-crossing. Here, we show that only the observable energy splitting coincides with band anti-crossing, while the switching point of the polarization can deviate from the anti-crossing point.
Stable single-mode operation of surface-emitting terahertz lasers with graded photonic heterostructure resonators
Authors: Xu Gangyi , Halioua Yacine , Moumdji Souad , Colombelli Raffaele , Beere Harvey E. , Ritchie David A.
Published: June 2013

Graded photonic heterostructures (GPH) can be regarded as energy wells for photons. We show that judicious engineering of such photonic wells, obtained by tailoring the grading and the slit width of the GPH resonator, allows one to ensure spectrally single-mode emission on the fundamental symmetric mode in the whole lasing dynamical range of terahertz quantum cascade lasers. Furthermore, the radiative character of the symmetric mode leads to single-mode emission with mW output power in continuous-wave operation, as well as to single-lobed far-field beam patterns. A careful combination of theoretical analysis and experimental observations reveals that the results stem from interplay between mode competition and spatial hole burning effects.
Ferroelectricity and dipole-dipole interactions in NH4TiOF3 mesocrystals
Authors: Liu Yanqiong , Kumar Amit , Fan Zhen , Zhang Yu , Ke Qingqing , Zeng Kaiyang , Wang John , Singh David J. , Ong Khuong P.
Published: June 2013

We report the discovery of ferroelectricity in NH4TiOF3 by piezoresponse force microscopy (PFM) technique and first principles calculations. The first principles calculations show that the O has an in-plane site preference in the layered structure of this material and the energetics favor a ferroelectric ground state with a calculated polarization of approximately 8 μC/cm2. Lateral and vertical PFM results show stable ferroelectricity at ambient temperature. The ferroelectricity is first observed for mesocrystals. It also provides an explanation for observations of mesocrystal growth even in the absence of surfactants since electric dipolar interactions can guide self-assembly.
Trap state controlled bipolar resistive switching effect and electronic transport in LaAlO3/Nb:SrTiO3 heterostructures
Authors: Jiang X. L. , Zhao Y. G. , Zhang X. , Zhu M. H. , Zhang H. Y. , Shang D. S. , Sun J. R.
Published: June 2013

We studied the resistive switching (RS) effect in LaAlO3/Nb:SrTiO3 heterostructures at different temperatures with AC impedance technique in addition to the conventional I–V measurements. It was demonstrated that the bipolar RS effect originates from LaAlO3/Nb:SrTiO3 interface and the resistance and capacitance states are controlled by the filling status of traps. A model based on the variation of trap state was proposed to explain the RS effect and the thermal history dependent electronic transport behavior. This work demonstrates the key role of trap state in the RS effect and electronic transport.
Anisotropic resistivity of tilted silver nanorod arrays: Experiments and modeling
Authors: Song Chunyuan , Larsen George K. , Zhao Yiping
Published: June 2013

Tilted Ag nanorod arrays with different nanorod lengths are fabricated by oblique angle deposition, and their anisotropic resistivities are investigated. Both the resistivity and its anisotropy decrease with increasing nanorod length. The experimental results can be accurately modeled using an analytical effective medium approximation of anisotropic bond percolation, where the bonds are metal nanorods and anisotropy results from the difference in node connectivity parallel with and perpendicular to the nanorod tilting direction.
Surface-based manipulation of point defects in rutile TiO2
Authors: Hollister Alice G. , Gorai Prashun , Seebauer Edmund G.
Published: June 2013

Through isotopic self-diffusion measurements, the present work resolves a discrepancy in the literature about the primary oxygen-related point defect in rutile TiO2 by showing that suitably prepared surfaces can controllably inject large numbers of an exceptionally mobile defect. Results strongly suggest that this defect is the oxygen interstitial, whose existence in TiO2 has been predicted computationally but never experimentally confirmed. The surface pathway offers an approach for replacing donor oxygen vacancies with acceptor oxygen interstitials facilitating manipulation of near-surface electronic bands.
Cavity-enhanced Raman scattering of single-walled carbon nanotubes
Authors: Sumikura Hisashi , Kuramochi Eiichi , Taniyama Hideaki , Notomi Masaya
Published: June 2013

We have demonstrated the cavity-enhanced Raman scattering of semiconducting single-walled carbon nanotubes (CNTs) deposited in a silicon photonic crystal (Si PhC) nanocavity. In a resonant nanocavity, the detected Raman intensity of the CNTs is 100 times larger than that of the CNTs on a flat Si film. This enhancement results from the large local density of photon states and the large light extraction efficiency of the nanocavity. The cavity-enhanced Raman scattering of the CNTs suggests a way to develop a low-threshold CNT-based Raman laser.
Increasing energy coupling into plasma waves by tailoring the laser radial focal spot distribution in a laser wakefield accelerator
Authors: Genoud G. , Bloom M. S. , Vieira J. , Burza M. , Najmudin Z. , Persson A. , Silva L. O. , Svensson K. , Wahlström C.-G. , Mangles S. P. D.
Published: June 2013

By controlling the focal spot quality with a deformable mirror, we are able to show that increasing the fraction of pulse energy contained within the central part of the focal spot, while keeping the total energy and central spot size constant, significantly increases the amount of energy transferred to the wakefield: Our measurements show that the laser loses significantly more laser energy and undergoes greater redshifting and that more charge is produced in the accelerated beam. Three dimensional particle in cell simulations performed with accurate representations of the measured focal spot intensity distribution confirm that energy in the wings of the focal spot is effectively wasted. Even though self-focusing occurs, energy in the wings of the focal spot distribution is not coupled into the wakefield, emphasising the vital importance of high quality focal spot profiles in experiments.
Structural magnetic loss of vertical aligned carbon fibres
Authors: Hong Wen , Xiao Peng , Luo Heng
Published: June 2013

The electromagnetic spectroscopy of vertical aligned carbon fibres (VACF) reinforced epoxy resin has been performed in the frequency range from 8.2 to 12.4 GHz. The composite was prepared by conventional epoxy polymerization. The results indicate VACF could possess magnetic loss and the structural magnetic properties could be tailored by adjusting the forest structure. The corresponding mechanism of the structural magnetic properties is proposed by the Faradays’ law of induction. The structural magnetism is further confirmed by measuring VACF reinforced Al2O3 composites in 1073 K environment. The measurement agrees well with the trend predicted by the parallel fibres model. These results represent a crucial step towards high temperature microwave absorber design and open a new avenue for realizing magnetic losses in the dielectric material.
Enhanced separation of magnetic and diamagnetic particles in a dilute ferrofluid
Authors: Liang Litao , Zhang Cheng , Xuan Xiangchun
Published: June 2013

Traditional magnetic field-induced particle separations take place in water-based diamagnetic solutions, where magnetic particles are captured while diamagnetic particles flow through without being affected by the magnetic field. We demonstrate that replacing the diamagnetic aqueous medium with a dilute ferrofluid can significantly increase the throughput of magnetic and diamagnetic particle separation. This enhancement is attributed to the simultaneous positive and negative magnetophoresis of magnetic and diamagnetic particles, respectively, in a ferrofluid. The particle transport behaviors in both ferrofluid- and water-based separations are predicted using an analytical model.
Magnetotransport of polycrystalline graphene: Shubnikov-de Haas oscillation and weak localization study
Authors: Yang X. C. , Wang H. M. , Wu T. R. , Huang F. Q. , Chen J. , Kang X. X. , Jin Z. , Xie X. M. , Jiang M. H.
Published: June 2013

Magnetotransport measurements were performed on a cross-junction made from polycrystalline graphene grown at a low temperature. The Shubnikov-de Haas oscillation is observed, from which the cyclotron mass mc can be derived varying from 0.043 to 0.055 times that of free electron. The changing rate of electron temperature is found much lower than that in pristine graphene via the universal electron heating study. Investigations on the characteristic lengths of weak localization reveal that the atomically sharp defects dominate the elastic scattering process, while studies on the coherent rate report that the Nyquist effect governs the inelastic scattering process with a little modulation from the direct Coulomb interaction. The scattering lengths in the polycrystalline graphene are comparable to that of exfoliated graphene on SiO2. These findings indicate that some key scattering parameters which characterize the excellent properties of intrinsic graphene are preserved in the polycrystalline graphene, which may find potential applications in interconnects of integrated circuit.
Functional helicoidal model of DNA molecule with elastic nonlinearity
Authors: Tseytlin Y. M.
Published: June 2013

We constructed a functional DNA molecule model on the basis of a flexible helicoidal sensor, specifically, a pretwisted hollow nano-strip. We study in this article the helicoidal nano- sensor model with a pretwisted strip axial extension corresponding to the overstretching transition of DNA from dsDNA to ssDNA. Our model and the DNA molecule have similar geometrical and nonlinear mechanical features unlike models based on an elastic rod, accordion bellows, or an imaginary combination of “multiple soft and hard linear springs”, presented in some recent publications.
The adhesion protein IgSF9b is coupled to neuroligin 2 via S-SCAM to promote inhibitory synapse development
Authors: Woo Jooyeon , Kwon Seok-Kyu , Nam Jungyong , Choi Seungwon , Takahashi Hideto , Krueger Dilja , Park Joohyun , Lee Yeunkum , Bae Jin Young , Lee Dongmin , Ko Jaewon , Kim Hyun , Kim Myoung-Hwan , Bae Yong Chul , Chang Sunghoe , Craig Ann Marie , Kim Eunjoon
Published: June 2013

Synaptic adhesion molecules regulate diverse aspects of synapse formation and maintenance. Many known synaptic adhesion molecules localize at excitatory synapses, whereas relatively little is known about inhibitory synaptic adhesion molecules. Here we report that IgSF9b is a novel, brain-specific, homophilic adhesion molecule that is strongly expressed in GABAergic interneurons. IgSF9b was preferentially localized at inhibitory synapses in cultured rat hippocampal and cortical interneurons and was required for the development of inhibitory synapses onto interneurons. IgSF9b formed a subsynaptic domain distinct from the GABAA receptor– and gephyrin-containing domain, as indicated by super-resolution imaging. IgSF9b was linked to neuroligin 2, an inhibitory synaptic adhesion molecule coupled to gephyrin, via the multi-PDZ protein S-SCAM. IgSF9b and neuroligin 2 could reciprocally cluster each other. These results suggest a novel mode of inhibitory synaptic organization in which two subsynaptic domains, one containing IgSF9b for synaptic adhesion and the other containing gephyrin and GABAA receptors for synaptic transmission, are interconnected through S-SCAM and neuroligin 2.
The incredible journey: From megakaryocyte development to platelet formation
Authors: Machlus Kellie R. , Italiano Joseph E.
Published: June 2013

Circulating blood platelets are specialized cells that prevent bleeding and minimize blood vessel injury. Large progenitor cells in the bone marrow called megakaryocytes (MKs) are the source of platelets. MKs release platelets through a series of fascinating cell biological events. During maturation, they become polyploid and accumulate massive amounts of protein and membrane. Then, in a cytoskeletal-driven process, they extend long branching processes, designated proplatelets, into sinusoidal blood vessels where they undergo fission to release platelets. Given the need for platelets in many pathological situations, understanding how this process occurs is an active area of research with important clinical applications.
HOT GAS LINES IN T TAURI STARS
Authors: Ardila David R. , Herczeg Gregory J. , Gregory Scott G. , Ingleby Laura , France Kevin , Brown Alexander , Edwards Suzan , Johns-Krull Christopher , Linsky Jeffrey L. , Yang Hao , Valenti Jeff A. , Abgrall Hervé , Alexander Richard D. , Bergin Edwin , Bethell Thomas , Brown Joanna M. , Calvet Nuria , Espaillat Catherine , Hillenbrand Lynne A. , Hussain Gaitee , Roueff Evelyne , Schindhelm Rebecca N. , Walter Frederick M.
Published: June 2013

For Classical T Tauri Stars (CTTSs), the resonance doublets of N v, Si iv, and C iv, as well as the He ii 1640 Å line, trace hot gas flows and act as diagnostics of the accretion process. In this paper we assemble a large high-resolution, high-sensitivity data set of these lines in CTTSs and Weak T Tauri Stars (WTTSs). The sample comprises 35 stars: 1 Herbig Ae star, 28 CTTSs, and 6 WTTSs. We find that the C iv, Si iv, and N v lines in CTTSs all have similar shapes. We decompose the C iv and He ii lines into broad and narrow Gaussian components (BC and NC). The most common (50%) C iv line morphology in CTTSs is that of a low-velocity NC together with a redshifted BC. For CTTSs, a strong BC is the result of the accretion process. The contribution fraction of the NC to the C iv line flux in CTTSs increases with accretion rate, from ∼20% to up to ∼80%. The velocity centroids of the BCs and NCs are such that V
BC ≳ 4 V
NC, consistent with the predictions of the accretion shock model, in at most 12 out of 22 CTTSs. We do not find evidence of the post-shock becoming buried in the stellar photosphere due to the pressure of the accretion flow. The He ii CTTSs lines are generally symmetric and narrow, with FWHM and redshifts comparable to those of WTTSs. They are less redshifted than the CTTSs C iv lines, by ∼10 km s−1. The amount of flux in the BC of the He ii line is small compared to that of the C iv line, and we show that this is consistent with models of the pre-shock column emission. Overall, the observations are consistent with the presence of multiple accretion columns with different densities or with accretion models that predict a slow-moving, low-density region in the periphery of the accretion column. For HN Tau A and RW Aur A, most of the C iv line is blueshifted suggesting that the C iv emission is produced by shocks within outflow jets. In our sample, the Herbig Ae star DX Cha is the only object for which we find a P-Cygni profile in the C iv line, which argues for the presence of a hot (105 K) wind. For the overall sample, the Si iv and N v line luminosities are correlated with the C iv line luminosities, although the relationship between Si iv and C iv shows large scatter about a linear relationship and suggests that TW Hya, V4046 Sgr, AA Tau, DF Tau, GM Aur, and V1190 Sco are silicon-poor, while CV Cha, DX Cha, RU Lup, and RW Aur may be silicon-rich.
Protein kinase A activates the Hippo pathway to modulate cell proliferation and differentiation
Authors: Yu Fa-Xing , Zhang Yifan , Park Hyun Woo , Jewell Jenna L. , Chen Qian , Deng Yaoting , Pan Duojia , Taylor Susan S. , Lai Zhi-Chun , Guan Kun-Liang
Published: June 2013

The Hippo tumor suppressor pathway plays an important role in tissue homeostasis that ensures development of functional organs at proper size. The YAP transcription coactivator is a major effector of the Hippo pathway and is phosphorylated and inactivated by the Hippo pathway kinases Lats1/2. It has recently been shown that YAP activity is regulated by G-protein-coupled receptor signaling. Here we demonstrate that cyclic adenosine monophosphate (cAMP), a second messenger downstream from Gαs-coupled receptors, acts through protein kinase A (PKA) and Rho GTPases to stimulate Lats kinases and YAP phosphorylation. We also show that inactivation of YAP is crucial for PKA-induced adipogenesis. In addition, PKA activation in Drosophila inhibits the expression of Yorki (Yki, a YAP ortholog) target genes involved in cell proliferation and death. Taken together, our study demonstrates that Hippo–YAP is a key signaling branch of cAMP and PKA and reveals new insight into mechanisms of PKA in regulating a broad range of cellular functions.
Multivalent histone engagement by the linked tandem Tudor and PHD domains of UHRF1 is required for the epigenetic inheritance of DNA methylation
Authors: Rothbart Scott B. , Dickson Bradley M. , Ong Michelle S. , Krajewski Krzysztof , Houliston Scott , Kireev Dmitri B. , Arrowsmith Cheryl H. , Strahl Brian D.
Published: June 2013

Histone post-translational modifications regulate chromatin structure and function largely through interactions with effector proteins that often contain multiple histone-binding domains. While significant progress has been made characterizing individual effector domains, the role of paired domains and how they function in a combinatorial fashion within chromatin are poorly defined. Here we show that the linked tandem Tudor and plant homeodomain (PHD) of UHRF1 (ubiquitin-like PHD and RING finger domain-containing protein 1) operates as a functional unit in cells, providing a defined combinatorial readout of a heterochromatin signature within a single histone H3 tail that is essential for UHRF1-directed epigenetic inheritance of DNA methylation. These findings provide critical support for the “histone code” hypothesis, demonstrating that multivalent histone engagement plays a key role in driving a fundamental downstream biological event in chromatin.
Phenotypic links among life‐history stages are complex and context‐dependent in a marine invertebrate: interactions among offspring size, larval nutrition and postmetamorphic density
Authors: Allen Richard M. , Marshall Dustin J.
Published: June 2013

Examples of simple phenotypic relationships, where variation in one stage directly affects phenotypic variation in a subsequent stage, are documented in most taxa. However, environmental variation can mediate these relationships, and because most organisms develop through multiple life‐history stages, each stage‐dependent environment has the potential to create new phenotypic relationships and interfere with existing relationships.

Despite the likelihood of complex phenotypic interactions among life‐history stages, and the potential for these interactions to resonate throughout the life history, there are few tests of the problem and few predictions of how these phenotypic interactions are resolved.

Here, we examined the interdependent effects of three sources of phenotypic variation on the performance of a marine tube worm. Sources of phenotypic variation included: offspring size, larval nutrition and juvenile density.

We found highly context‐dependent relationships between these factors and postmetamorphic performance. Within the overarching result of context dependence, we found: interactions could negate and reverse relationships; early‐stage phenotypes could persist to postmetamorphosis; later, life‐history environments could contribute more to recruit phenotypes than early‐stages; and late‐stage variation can depend on early‐stage phenotypes.

Our results demonstrate that while simple phenotypic links among the egg, larval and postrecruitment stages may be common and important contributors to growth and survival, these relationships should be considered in the context of the organism's life experience. Each phenotypic link among stages can potentially be complex and depend on prior experience, current state and the subsequent environments experienced.