bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Giardia Trophozoites in Archival Pathology
Specimens of Human Small Intestine
Authors: Macechko P. Timothy , van Keulen Harry , Jarroll Edward L. , Mulgrew Thomas , Gurien Andrew , Erlandsen Stanley L.
Published: April 2013

The examination of archival pathology specimens of human small
intestine by light microscopy, field emission scanning electron microscopy
(FESEM), and confocal scanning laser microscopy using fluorescent in situ
hybridization (FISH) techniques was undertaken to better understand the
epidemiology of Giardia. Giardia trophozoites were
tentatively identified in the light microscope after hematoxylin and eosin
(H&E) staining. The organisms were adherent to the intestinal
epithelium where they were also associated with strands of mucus within
the lumen. Fluorochrome-conjugated antisense oligonucleotide probes,
developed for the 16S rRNA of Giardia lamblia and Giardia
muris, were used in FISH experiments with confocal scanning laser
microscopy. Positive identification of trophozoites could be obtained with
the G. lamblia probe, but not with the G. muris probe.
FESEM examination of serial sections adjacent to FISH-stained sections
revealed trophozoites characterized by their morphological features. The
16S rDNA probes specifically distinguished different species of
Giardia, but whether multiple infections can occur within an
individual host could not be determined.
Does Crystal Tilt Enhance the Electron Interaction?
Authors: Van Dyck D. , Bokel R.M.J. , Zandbergen H.W.
Published: April 2013

We have observed that a slight crystal tilt away from the zone axis
paradoxically decreases the dynamical extinction length, as if the
electron-crystal interaction increases. This effect disappears at larger
tilt angles. Using the simplified channeling theory, this behavior is
explained.
Cytokine and Eicosanoid Production by Cultured Human Monocytes Exposed to Titanium Particulate Debris
Authors: Robinson Timothy M. , Manley Paul A. , Sims Paul A. , Albrecht Ralph , Darien Benjamin J.
Published: April 2013

Phagocytosis of particulate wear debris from arthroplasties by macrophages induces an inflammatory
response that has been linked to implant loosening and premature failure of artificial joints. Inflammatory
mediators released by phagocytic macrophages such as tumor necrosis factor-a (TNF-α), interleukin-1β
(IL-1β), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) are believed to play a central role in the pathogenesis
of aseptic loosening. The objective of this study was to characterize titanium alloy particulates that closely match
wear debris found around joint arthroplasties and to study their effects on the biosynthesis of inflammatory
mediators by cultured monocytes. Peripheral blood monocytes were isolated from healthy human volunteers.
Monocytes were cultured in 96-well plates for 24 h, washed, and exposed to three concentrations of titanium
particulates and controls from 18Ð24 h. Supernatants were assayed for TNF-α, IL-1β, IL-6, and PGE2 activity.
Energy dispersive X-ray spectroscopy (EDX) verified the titanium alloy to be Ti6A14V. Scanning electron
microscopy (SEM) analysis showed significant titanium particulate heterogeneity with approximately 95% of
the particles <1 micrometer in diameter. SEM and EDX technology was useful in the characterization of the titanium
particulates utilized for in vitro models of titanium-induced cytokine release by monocytes. Incubation of
titanium particulates (in concentrations similar to those found around loosened prosthetic joints) with cultured
monocytes significantly increased their production of TNF-α, IL-1β, and PGE2.
Electron Microscopy Methods and Protocols
(Volume 17 of the Series on Methods in
Molecular Biology), Edited by M.A. Nasser Hajibagheri
1999. Humana Press, Totowa, NJ. xi + 281 pages. ($89.50)
Authors: Bendayan Moise
Published: April 2013

At first glance, this book seems to come up short with
regard to the application of electron microscopy in biological
sciences. However, one has to consider that it is part of
a series on molecular biology. The purpose here was not to
collect a large variety of techniques related to electron microscopy
but rather to focus on methods in molecular morphology.
In this context, the book offers 15 short (some
very short) chapters dealing with morphological approaches
related to and used in molecular biology.
Comparative Study of Field Emission-Scanning Electron Microscopy and Atomic Force Microscopy to Assess Self-assembled Monolayer Coverage on Any Type of Substrate
Authors: Neves Bernardo R.A. , Salmon Michael E. , Russell Phillip E. , Troughton E. Barry
Published: April 2013

Abstract: In this work, we show how field emission–scanning electron microscopy (FE-SEM) can be a useful tool for the study of self-assembled monolayer systems. We have carried out a comparative study using FE-SEM and atomic force microscopy (AFM) to assess the morphology and coverage of self-assembled monolayers (SAM) on different substrates. The results show that FE-SEM images present the same qualitative information obtained by AFM images when the SAM is deposited on a smooth substrate (e.g., mica). Further experiments with rough substrates (e.g., Al grains on glass) show that FE-SEM is capable of unambiguously identifying SAMs on any type of substrate, whereas AFM has significant difficulties in identifying SAMs on rough surfaces.
Outcome and patient-reported toxicity in localised prostate cancer treated with dose-escalated hypofractionated intensity-modulated radiotherapy
Authors: Thomson David , Merrick Sophie , Swindell Ric , Wylie James , Cowan Richard , Elliott Tony , Logue John , Livsey Jacqueline , Choudhury Ananya
Published: April 2013

Objective

To report outcomes and late toxicity for a hypofractionated dose-escalated radiotherapy schedule in patients treated using intensity-modulated radiotherapy (IMRT) for localised prostate cancer.

Materials and methods

Eighty-eight men with localised prostate cancer were treated with 57 Gy in 19 daily fractions over 4 weeks. A total of 70 out of 88 had high-risk disease. Overall survival, cause-specific survival and biochemical progression-free survival (bPFS, Phoenix definition) were reported. Toxicity was measured retrospectively using Radiation Therapy Oncology Group (RTOG) criteria and assessed prospectively with a validated Late Effects in Normal Tissues Subjective, Objective, Management and Analytic (LENT/SOMA) patient questionnaire.

Results

At 5 years, overall survival was 84%, cause-specific survival 88% and bPFS 65%. In patients with high-risk disease, 5-year bPFS was 62%. There was no RTOG toxicity above grade III. LENT/SOMA questionnaires were returned by 74% patients. Median scores for bowel and urinary function were <1. Maximum bowel and urinary toxicity scores ≥2 were reported by 64% and 59% of patients, respectively. The median score for sexual function was 1·5, but nearly all (96%) patients recorded a toxicity score ≥2 for at least one question.

Conclusions

Dose-escalated hypofractionated radiotherapy delivered using IMRT has promising outcomes and acceptable late toxicity. This fractionation schedule is being compared with conventional treatment within an on-going multicentre phase III clinical trial.
Miniature single-sideband subharmonically-pumped 60 GHz direct upconverter in a uniplanar GaAs pHEMT technology using inductive and capacitive loading techniques
Authors: Hettak Khelifa , Ross Tyler N. , Irfan Nazish , Cormier Gabriel , Yagoub Mustapha C. E. , Morin Gilbert A. , Wight Jim S.
Published: April 2013

This paper presents a novel, compact, single-sideband (SSB) subharmonically-pumped (SHP) direct upconverter developed in a uniplanar 0.18 μm GaAs technology. A total of 100 MHz in-phase and quadrature signals directly modulate the second harmonic of a 30 GHz carrier signal, producing a 60.1 GHz output. Two pairs of antiparallel diodes reduce feed-through of the 30 GHz local oscillator (LO) signal to the mixer's RF output. Novel structures patterned in the center conductor of a coplanar waveguide (CPW) provide matching and size-reduction simultaneously. The 2.1mm2 circuit also uses a miniaturized Wilkinson divider based on asymmetric coplanar stripline and a standard CPW 90° coupler. The SSB SHP direct upconverter exhibits a conversion loss of 10 dB, a lower-sideband rejection of 15 dB and 2fLO suppression of approximately 25 dB over a wide frequency range from 52–61 GHz.
MEMS reconfigurable millimeter-wave surface for V-band rectangular-waveguide switch
Authors: Baghchehsaraei Zargham , Shah Umer , Åberg Jan , Stemme Göran , Oberhammer Joachim
Published: April 2013

This paper presents for the first time a novel concept of a microelectromechanical systems (MEMS) waveguide switch based on a reconfigurable surface, whose working principle is to block the wave propagation by short-circuiting the electrical field lines of the TE10 mode of a WR-12 rectangular waveguide. The reconfigurable surface is only 30 µm thick and consists of up to 1260 micromachined cantilevers and 660 contact points in the waveguide cross-section, which are moved simultaneously by integrated MEMS comb-drive actuators. Measurements of fabricated prototypes show that the devices are blocking wave propagation in the OFF-state with over 30 dB isolation for all designs, and allow for transmission of less than 0.65 dB insertion loss for the best design in the ON-state for 60–70 GHz. Furthermore, the paper investigates the integration of such microchips into WR-12 waveguides, which is facilitated by tailor-made waveguide flanges and compliant, conductive-polymer interposer sheets. It is demonstrated by reference measurements where the measured insertion loss of the switches is mainly attributed to the chip-to-waveguide assembly. For the first prototypes of this novel MEMS microwave device concept, the comb-drive actuators did not function properly due to poor fabrication yield. Therefore, for measuring the OFF-state, the devices were fixated mechanically.
Pandora's box? Drone strikes underjus ad bellum, jus in bello, and international human rights law
Authors: Casey-Maslen Stuart
Published: April 2013

Armed drones pose a major threat to the general prohibition on the inter-state use of force and to respect for human rights. On the battlefield, in a situation of armed conflict, the use of armed drones may be able to satisfy the fundamental international humanitarian law rules of distinction and proportionality (although attributing international criminal responsibility for their unlawful use may prove a significant challenge). Away from the battlefield, the use of drone strikes will often amount to a violation of fundamental human rights. Greater clarity on the applicable legal regime along with restraints to prevent the further proliferation of drone technology are urgently needed.
La vitesse de l'onde de pouls et la pression artérielle centrale devraient-elles être mesurées chez les patients hypertendus?
Authors: Muller Marie-Eve , Zimmerli Lukas , Burnier Michel , Wuerzner Grégoire
Published: April 2013

Diagnose und Behandlung der arteriellen Hypertonie sind notwendig, um die verbundene Mortalität und Morbidität zu reduzieren. Die Entscheidung zur Behandlung von Bluthochdruck basiert oft auf wiederholten Praxisblutdruckmessungen. Neue nicht-invasive Messungen wie die Pulswellengeschwindigkeit oder zentrale Blutdruckmessung können sich jedoch als nützlich erweisen, um das kardiovaskuläre Risiko mit mehr Präzision zu beurteilen. Die Pulswellengeschwindigkeit ist ein Marker für arterielle Steifigkeit, die einen unabhängigen Risikofaktor für zukünftige kardiovaskuläre Ereignisse darstellt. Nicht-pharmakologische und pharmakologische Therapien können arterielle Steifigkeit und zentralen Blutdruck beeinflussen. Weitere Studien werden allerdings benötigt, um zu entscheiden, ob diese Messungen als neue Standarduntersuchung für kardiovaskuläre Erkrankungen verwendet werden können.
In der Praxis lernen
Authors: Bohrer Annerose
Published: April 2013

Was Lernende in der Praxis lernen, wie sie dies tun und wie sie ihr Lernen in der Praxis erleben, steht im Mittelpunkt dieses Beitrags. Die Ergebnisse sind Teil einer qualitativen Studie zum Lernen in der Pflegepraxis.
Perceived Stops to Suicidal Thoughts, Plans, and Actions in Persons Experiencing Psychosis
Authors: Gooding P. A. , Sheehy K. , Tarrier N.
Published: April 2013

Background: Suicide has been conceived as involving a continuum, whereby suicidal plans and acts emerge from thoughts about suicide. Suicide prevention strategies need to determine whether different responses are needed at these points on the continuum. Aims: This study investigates factors that were perceived to counter suicidal ideation, plans, and acts. Method: The 36 participants, all of whom had had experiences of psychosis and some level of suicidality, were presented with a vignette describing a protagonist with psychotic symptoms. They were asked to indicate what would counter the suicidal thoughts, plans, and acts of the protagonist described in the vignette. Qualitative techniques were first used to code these free responses into themes/categories. Correspondence analysis was then applied to the frequency of responses in each of these categories. Results: Social support was identified as a strong counter to suicidal ideation but not as a counter to suicidal plans or acts. Help from health professionals was strongly related to the cessation of suicidal plans as were the opinions of the protagonist’s children. Changing cognitions and strengthening psychological resources were more weakly associated with the cessation of suicidal ideation and plans. The protagonist’s children were considered potentially helpful in addressing suicidal acts. Conclusion: These results suggest that both overlapping and nonoverlapping factors need to be considered in understanding suicide prevention, dependent on whether individuals are thinking about, planning, or attempting suicide.
Prevalence and Risk Factors of Attempted Suicide in Adult War-Affected Population of Eastern Uganda
Authors: Kinyanda Eugene , Weiss Helen A. , Mungherera Margaret , Onyango-Mangen Patrick , Ngabirano Emmanuel , Kajungu Rehema , Kagugube Johnson , Muhwezi Winston , Muron Julius , Patel Vikram
Published: April 2013

Background: There is conflicting evidence on the relationship between war trauma and suicidal behavior. Some studies point to an increased risk of suicidal behavior while others do not, with a paucity of such data from sub-Saharan Africa. Aims: To investigate the prevalence and risk factors of attempted suicide in war-affected Eastern Uganda. Method: A cross-sectional survey was carried out in two districts of Eastern Uganda where 1,560 respondents (15 years and older) were interviewed. Multivariable logistic regression was used to assess risk factors of attempted suicide in this population. Results: Lifetime attempted suicide was 9.2% (n = 142; 95% CI, 7.8%–10.8%), and 12-month attempted suicide was 2.6% (n = 41; 95% CI, 1.9–3.5%). Lifetime attempted suicide was significantly higher among females 101 (11.1%) than among males 43 (6.5%; OR = 1.80, 95% CI 1.21–2.65). Factors independently associated with lifetime rate of attempted suicide among females were subcounty, being a victim of intimate partner violence, having reproductive health complaints, and having major depressive disorder. Among males these were belonging to a war-vulnerable group, having a surgical complaint, and having a major depressive disorder. Conclusions: In both sexes, the lifetime rate of attempted suicide was not independently directly related to experiences of war trauma. It was, however, indirectly related to war trauma through its association with psychological, somatic, and psychosocial sequelae of war.
The role of doublesex in the evolution of exaggerated horns in the Japanese rhinoceros beetle
Authors: Ito Yuta , Harigai Ayane , Nakata Moe , Hosoya Tadatsugu , Araya Kunio , Oba Yuichi , Ito Akinori , Ohde Takahiro , Yaginuma Toshinobu , Niimi Teruyuki
Published: April 2013

Male‐specific exaggerated horns are an evolutionary novelty and have diverged rapidly via intrasexual selection. Here, we investigated the function of the conserved sex‐determination gene doublesex (dsx) in the Japanese rhinoceros beetle (Trypoxylus dichotomus) using RNA interference (RNAi). Our results show that the sex‐specific T. dichotomus dsx isoforms have an antagonistic function for head horn formation and only the male isoform has a role for thoracic horn formation. These results indicate that the novel sex‐specific regulation of dsx during horn morphogenesis might have been the key evolutionary developmental event at the transition from sexually monomorphic to sexually dimorphic horns.
The dark matter rises: the expanding world of regulatory RNAs
Authors: Clark Michael B. , Choudhary Anupma , Smith Martin A. , Taft Ryan J. , Mattick John S.
Published: April 2013

The ability to sequence genomes and characterize their products has begun to reveal the central role for regulatory RNAs in biology, especially in complex organisms. It is now evident that the human genome contains not only protein-coding genes, but also tens of thousands of non–protein coding genes that express small and long ncRNAs (non-coding RNAs). Rapid progress in characterizing these ncRNAs has identified a diverse range of subclasses, which vary widely in size, sequence and mechanism-of-action, but share a common functional theme of regulating gene expression. ncRNAs play a crucial role in many cellular pathways, including the differentiation and development of cells and organs and, when mis-regulated, in a number of diseases. Increasing evidence suggests that these RNAs are a major area of evolutionary innovation and play an important role in determining phenotypic diversity in animals.
Partial transpose of random quantum states: Exact formulas and meanders
Authors: Fukuda Motohisa , Śniady Piotr
Published: April 2013

We investigate the asymptotic behavior of the empirical eigenvalues distribution of the partial transpose of a random quantum state. The limiting distribution was previously investigated via Wishart random matrices indirectly (by approximating the matrix of trace 1 by the Wishart matrix of random trace) and shown to be the semicircular distribution or the free difference of two free Poisson distributions, depending on how dimensions of the concerned spaces grow. Our use of Wishart matrices gives exact combinatorial formulas for the moments of the partial transpose of the random state. We find three natural asymptotic regimes in terms of geodesics on the permutation groups. Two of them correspond to the above two cases; the third one turns out to be a new matrix model for the meander polynomials. Moreover, we prove the convergence to the semicircular distribution together with its extreme eigenvalues under weaker assumptions, and show large deviation bound for the latter.
Inverting pump-probe spectroscopy for state tomography of excitonic systems
Authors: Hoyer Stephan , Whaley K. Birgitta
Published: April 2013

We propose a two-step protocol for inverting ultrafast spectroscopy experiments on a molecular aggregate to extract the time-evolution of the excited state density matrix. The first step is a deconvolution of the experimental signal to determine a pump-dependent response function. The second step inverts this response function to obtain the quantum state of the system, given a model for how the system evolves following the probe interaction. We demonstrate this inversion analytically and numerically for a dimer model system, and evaluate the feasibility of scaling it to larger molecular aggregates such as photosynthetic protein-pigment complexes. Our scheme provides a direct alternative to the approach of determining all Hamiltonian parameters and then simulating excited state dynamics.
Spectroscopy of the double minimum 3 3ΠΩ electronic state of 39K85Rb
Authors: Banerjee Jayita , Rahmlow David , Carollo Ryan , Bellos Michael , Eyler Edward E. , Gould Phillip L. , Stwalley William C.
Published: April 2013

We report the observation and analysis of the 3 3ΠΩ double-minimum electronic excited state of 39K85Rb. The spin-orbit components (0+, 0−, 1, and 2) of this state are investigated based on potentials developed from the available ab initio potential curves. We have assigned the vibrational levels v′ = 2–11 of the 3 3Π1,2 potentials and v′ = 2–12 of the \documentclass[12pt]{minimal}\begin{document}$3\,^3\Pi _{0^{+/-}}$\end{document}3Π0+/−3 potential. We compare our experimental observations of the 3 3ΠΩ state with predictions based on theoretical potentials. The observations are based on resonance enhanced multiphoton ionization of ultracold KRb in vibrational levels v″ = 14–25 of the a 3Σ+ state. These a-state ultracold molecules are formed by photoassociation of ultracold 39K and 85Rb atoms to the 5(1) state of KRb followed by spontaneous emission to the a state.
Estimates on the eigenvalues of the clamped plate problem on domains in Euclidean spaces
Authors: Yolcu Selma Yıldırım , Yolcu Türkay
Published: April 2013

The purpose of this article is two-fold. First, we obtain some certain bounds for the sums of (positive and negative) powers of the eigenvalues of the clamped plate problem of the Dirichlet bi-Laplacian operator \documentclass[12pt]{minimal}\begin{document}$\Delta ^{2}|_{{\mathcal {D}}}$\end{document}Δ2|D, restricted to a bounded domain \documentclass[12pt]{minimal}\begin{document}${\mathcal {D}}\subset {\mathbb {R}}^d$\end{document}D⊂Rd with d ⩾ 2. Second, we establish lower bounds for the sums of eigenvalues of \documentclass[12pt]{minimal}\begin{document}$\Delta ^2|_{{\mathcal {D}}}$\end{document}Δ2|D sharper than the bounds recently obtained by Cheng and Wei [“A lower bound for eigenvalues of a clamped plate problem,” Calculus Var. Partial Differ. Equ. 42(3–4), 579–590 (2011)]10.1007/s00526-011-0399-6. All these estimates are sharp in the sense of Weyl asymptotics.
Functional Wigner representation of quantum dynamics of Bose-Einstein condensate
Authors: Opanchuk B. , Drummond P. D.
Published: April 2013

We develop a method of simulating the full quantum field dynamics of multi-mode multi-component Bose-Einstein condensates in a trap. We use the truncated Wigner representation to obtain a probabilistic theory that can be sampled. This method produces c-number stochastic equations which may be solved using conventional stochastic methods. The technique is valid for large mode occupation numbers. We give a detailed derivation of methods of functional Wigner representation appropriate for quantum fields. Our approach describes spatial evolution of spinor components and properly accounts for nonlinear losses. Such techniques are applicable to calculating the leading quantum corrections, including effects such as quantum squeezing, entanglement, EPR correlations, and interactions with engineered nonlinear reservoirs. By using a consistent expansion in the inverse density, we are able to explain an inconsistency in the nonlinear loss equations found by earlier authors.
Exact quantum scattering calculations of transport properties: CH2($\tilde{X}^3$X̃3B1, $\tilde{a}^1$ã1A1)–helium
Authors: Dagdigian Paul J. , Alexander Millard H.
Published: April 2013

Transport properties for collisions of methylene, in both its ground \documentclass[12pt]{minimal}\begin{document}$\tilde{X}^3B_1$\end{document}X̃3B1 and low-lying \documentclass[12pt]{minimal}\begin{document}$\tilde{a}^1A_1$\end{document}ã1A1 electronic states, with helium have been computed using recently computed high-quality ab initio potential energy surfaces (PESs). Because of the difference in the orbital occupancy of the two electronic states, the anisotropies of the PESs are quite different. The CH2(\documentclass[12pt]{minimal}\begin{document}$\tilde{a}$\end{document}ã)–He PES is very anisotropic because of the strong interaction of the electrons on the helium atom with the unoccupied CH2 orbital perpendicular to the molecular plane, while the anisotropy of the CH2(\documentclass[12pt]{minimal}\begin{document}$\tilde{X}$\end{document}X̃)–He PES is significantly less since this orbital is singly occupied in this case. To investigate the importance of the anisotropy on the transport properties, calculations were performed with the full potential and with the spherical average of the potential for both electronic states. Significant differences (over 20% for the \documentclass[12pt]{minimal}\begin{document}$\tilde{a}$\end{document}ã state at the highest temperatures considered) in the computed transport properties were found.
SODI-COLLOID: A combination of static and dynamic light scattering on board the International Space Station
Authors: Mazzoni S. , Potenza M. A. C. , Alaimo M. D. , Veen S. J. , Dielissen M. , Leussink E. , Dewandel J.-L. , Minster O. , Kufner E. , Wegdam G. , Schall P.
Published: April 2013

Microgravity research in space is a complex activity where the often scarce resources available for the launch, accommodation, and operation of instrumentation call for a careful experiment planning and instrument development. In this paper we describe a module of the Selectable Optical Diagnostic Instrument, that has been designed as a compact optical diagnostic instrument for colloidal physics experiments. The peculiarity of the instrument is the combination of a novel light scattering technique known as near field scattering and standard microscopy with a low-coherence laser light source. We describe its main design features, as well as measurement results on colloidal aggregation taken on the International Space Station.
Prediction of 2D Rydberg energy levels of 6Li and 7Li based on very accurate quantum mechanical calculations performed with explicitly correlated Gaussian functions
Authors: Bubin Sergiy , Sharkey Keeper L. , Adamowicz Ludwik
Published: April 2013

Very accurate variational nonrelativistic finite-nuclear-mass calculations employing all-electron explicitly correlated Gaussian basis functions are carried out for six Rydberg 2D states (1s2nd, n = 6, …, 11) of the 7Li and 6Li isotopes. The exponential parameters of the Gaussian functions are optimized using the variational method with the aid of the analytical energy gradient determined with respect to these parameters. The experimental results for the lower states (n = 3, …, 6) and the calculated results for the higher states (n = 7, …, 11) fitted with quantum-defect-like formulas are used to predict the energies of 2D 1s2nd states for 7Li and 6Li with n up to 30.
Size and shape of industrial Pd catalyst particles using size-selected clusters as mass standards
Authors: Pearmain D. , Park S. J. , Wang Z. W. , Abdela A. , Palmer R. E. , Li Z. Y.
Published: April 2013

The complexity of the morphology of industrial catalysts presents a significant challenge to rapid screening techniques. Here, we propose a strategy in determining three-dimensional shape of industrial catalyst particles using a combination of scanning transmission electron microscopy (STEM) as a quantitative probe and size-selected clusters as mass standards. We show that through STEM image intensity analysis, this approach allows us to evaluate the number of atoms within each particle and thus gain insight into the overall 3D morphology of the catalyst particles. It is found that the industrial Pd catalysts on carbon blacks have hemispherical shape, in contrast to the spherical shape of Pd clusters formed in the gas phase and soft-landed on supports.
Linear response approximation to reference interaction site model self-consistent field explicitly including spatial electron density distribution. Free energy
Authors: Yokogawa D.
Published: April 2013

We proposed linear response approximation to reference interaction site model self-consistent field explicitly including spatial electron density distribution (RISM-SCF-SEDD). Because the electrostatic potential induced by solvent molecules is approximated by linear response to the density change of solute molecule, new algorithm becomes significantly simple compared to the original RISM-SCF-SEDD. The present method was applied to simple molecules and p-nitroaniline (PNA). The maximum relative error of the linear response approximation is less than 1.0% in the solvation free energies of the simple molecules. The present method also achieved a stable calculation of PNA.
Dominating recombination mechanisms in organic solar cells based on ZnPc and C60
Authors: Tress Wolfgang , Leo Karl , Riede Moritz
Published: April 2013

We investigate the dominating recombination mechanisms in bulk heterojunction solar cells, using a blend of ZnPc and C60 as model system. Analyzing the open-circuit voltage (Voc) as a function of illumination intensity, we find that trap-assisted recombination dominates for low light intensities, whereas at 1 sun, direct/bimolecular recombination becomes important. The recombination parameters are not significantly influenced by the blend mixing ratio and are also valid for injected charges. By changing the hole transport layer, recombination at the contact is separately identified as further mechanism reducing Voc at higher light intensities.
Influence of donor-acceptor layer sequence on photoresponsive organic field-effect transistors based on palladium phthalocyanine and C60
Authors: Chen Deqiang , Yao Bo , Fan Guoying , Lv Wenli , Gao Pengjie , Zhou Maoqing , Peng Yingquan
Published: April 2013

Photoresponsive organic field-effect transistors (PhotOFETs) based on palladium phthalocyanine (PdPc) and C60 were fabricated with different donor-acceptor layer sequences. Both planar heterojunction devices fabricated exhibit better performance under illumination than the single PdPc device. PhotOFETs with the structure SiO2/C60/PdPc/Au exhibit a higher photosensitivity and photoresponsivity than that with the structure SiO2/PdPc/C60/Au. The origin for this is largely the high mobility of C60 and the well-matched LUMO levels of PdPc and C60. The maximum photosensitivity of the SiO2/C60/PdPc/Au device is 8 × 103, and the photoresponsivity is approximately 28 times that of the single component PdPc device.
Interactive manipulation of microparticles in an octagonal sonotweezer
Authors: Bernassau A. L. , Courtney C. R. P. , Beeley J. , Drinkwater B. W. , Cumming D. R. S.
Published: April 2013

An ultrasonic device for micro-patterning and precision manipulation of micrometre-scale particles is demonstrated. The device is formed using eight piezoelectric transducers shaped into an octagonal cavity. By exciting combinations of transducers simultaneously, with a controlled phase delay between them, different acoustic landscapes can be created, patterning micro-particles into lines, squares, and more complex shapes. When operated with all eight transducers the device can, with appropriate phase control, manipulate the two dimensional acoustic pressure gradient; it thus has the ability to position and translate a single tweezing zone to different locations on a surface in a precise and programmable manner.
Reversible Mn segregation at the polar surface of lithium tetraborate
Authors: Dugan Christina , Hengehold Robert L. , McHale Steve R. , Colón Santana Juan A. , McClory John W. , Adamiv V. T. , Burak Ya. V. , Losovyj Ya. B. , Dowben Peter A.
Published: April 2013

We find Mn surface segregation for single crystals of Mn doped Li2B4O7, nominally Li1.95Mn0.05B4O7(001), but as the temperature increases, evidence of this Mn surface segregation diminishes significantly. At room temperature, the surface photovoltaic charging is significant for this pyroelectric material but is quenched at a temperature well below that seen for the undoped Li2B4O7 samples. The suppression of surface charging in the region of 120 °C that accompanies the temperature of Mn dissolution in the bulk of Li2B4O7, i.e., the reversal of Mn surface segregation (215 °C), suggests that along the (001) direction, ionic transport must be considered as significant.
Heterogeneous in-situ nanostructure contributes to the thermoelectric performance of Zn4Sb3
Authors: Lin Jianping , Qiao Guanjun , Ma Lingzhi , Ren Yang , Yang Baifeng , Fei Youjian , Lei Lei
Published: April 2013

Single-phase Zn4Sb3 and ZnSb-containing samples were prepared by Plasma Activated Sintering. An abrupt decrease of thermal conductivity was found at about 400 K, which is attributed to the microstructure change of Zn4Sb3. Nanoscale inclusions and compositional inhomogeneities were found in Zn4Sb3 sample at 473 K by high-resolution transmission electron microscopy. The phonon scattering is enhanced by increasing grain boundaries and chaotic structure, which reduces the thermal conductivity and increases the thermoelectric performance of Zn4Sb3 at elevated temperature. The Rietveld refinement results show that large ZnSb grains in ZnSb-containing samples will accommodate excess Zn atoms, and then reduce thermoelectric performance.
Laser-plasma source parameters for Kr, Gd, and Tb ions at 6.6 nm
Authors: Masnavi Majid , Szilagyi John , Parchamy Homaira , Richardson Martin C.
Published: April 2013

There is increasing interest in extreme-ultraviolet (EUV) laser-based lamps for sub-10-nm lithography operating in the region of 6.6 nm. A collisional-radiative model is developed as a post-processor of a hydrodynamic code to investigate emission from resonance lines in Kr, Gd, and Tb ions under conditions typical for mass-limited EUV sources. The analysis reveals that maximum conversion efficiencies of Kr occur at 5×1010W/cm2, while for Gd and Tb it was ≃0.9%/2πsr for laser intensities of (2−5)×1012W/cm2.
Graphene based piezoresistive pressure sensor
Authors: Zhu Shou-En , Krishna Ghatkesar Murali , Zhang Chao , Janssen G. C. A. M.
Published: April 2013

We present a pressure sensor based on the piezoresistive effect of graphene. The sensor is a 100 nm thick, 280 μm wide square silicon nitride membrane with graphene meander patterns located on the maximum strain area. The multilayer, polycrystalline graphene was obtained by chemical vapor deposition. Strain in graphene was generated by applying differential pressure across the membrane. Finite element simulation was used to analyze the strain distribution. By performing electromechanical measurements, we obtained a gauge factor of ∼1.6 for graphene and a dynamic range from 0 mbar to 700 mbar for the pressure sensor.
Agglomeration dynamics of germanium islands on a silicon oxide substrate: A grazing incidence small-angle x-ray scattering study
Authors: Cheynis F. , Leroy F. , Passanante T. , Müller P.
Published: April 2013

Grazing-incidence small-angle X-ray scattering (GISAXS) and grazing-incidence X-ray diffraction techniques are used to characterise the thermally induced solid-state dewetting of Ge(001) thin films leading to the formation of 3D Ge islands. A quantitative analysis based on the Kolmogorov-Johnson-Mehl-Avrami model is derived. The main physical parameters controlling the dewetting (activation energy and kinetic pre-factors) are determined. Assuming that the dewetting is driven by surface/interface minimisation and limited by surface diffusion, the Ge surface self-diffusion reads as Ds,0c0 e−Ea/(kBT) ∼3×1018 e−2.6±0.3 eV/(kBT) nm2/s. GISAXS technique enables to reconstruct the mean Ge-island shape, including facets.
Fast hydrogen-induced optical and electrical transitions of Mg and Mg-Ni films with amorphous structure
Authors: Zhao Qiyang , Li Yongtao , Song Yun , Cui Xiaoli , Sun Dalin , Fang Fang
Published: April 2013

Amorphous Mg and MgNix (x = 0.03–0.30) films were prepared and their optical and electrical transitions upon hydrogen loading/unloading at room temperature were investigated. The results show that amorphous films have faster optical and electrical transitions than corresponding crystalline ones. Amorphous structure greatly facilitates hydrogen diffusion, resulting in not only preventing the formation of blocking hydrides layers but also changing the rate-controlling step from hydrogen diffusion for crystalline film to the reaction between hydrogen and Mg and/or Mg-Ni phases. We envision that amorphization is generally applicable to improve hydrogen-induced response characteristics of switchable mirror thin films.
Efficient polymer solar cells with a solution-processed gold chloride as an anode interfacial modifier
Authors: Go Yeong-Jin , Yun Jin-Mun , Noh Yong-Jin , Yeo Jun-Seok , Kim Seok-Soon , Jung Chan-Hee , Oh Seung-Hwan , Yang Shi-Young , Kim Dong-Yu , Na Seok-In
Published: April 2013

The use of a solution-processed gold chloride (AuCl3) as an anode interfacial modifier was investigated for high-performance polymer solar cells (PSCs). Kelvin probe, 4-point probe, and X-ray photoelectron spectroscopy studies demonstrated that AuCl3 increases the indium-tin-oxide (ITO) work-function and decreases the ITO sheet resistance, because of Au nanoparticle formation and Cl adsorption by the AuCl3 treatment to induce a p-doping effect, thereby improving the built-in potential and interface resistance. As a result, the introduction of AuCl3 by simple solution processing remarkably improved cell-performances, indicating that AuCl3 is an efficient anode interfacial modifier for enhancing PSC-performance.
The Binocular Advantage in Visuomotor Tasks Involving Tools
Authors: Read Jenny C. A. , Begum Shah Farzana , McDonald Alice , Trowbridge Jack
Published: April 2013

We compared performance on three manual-dexterity tasks under monocular and binocular viewing. The tasks were the standard Morrisby Fine Dexterity Test, using forceps to manipulate the items, a modified version of the Morrisby test using fingers, and a “buzz-wire” task in which subjects had to guide a wire hoop around a 3D track without bringing the hoop into contact with the track. In all three tasks, performance was better for binocular viewing. The extent of the binocular advantage in individuals did not correlate significantly with their stereoacuity measured on the Randot test. However, the extent of the binocular advantage depended strongly on the task. It was weak when fingers were used on the Morrisby task, stronger with forceps, and extremely strong on the buzz-wire task (fivefold increase in error rate with monocular viewing). We suggest that the 3D buzz-wire game is particularly suitable for assessing binocularly based dexterity.
On Why Music Changes What (We Think) We Taste
Authors: Spence Charles , Deroy Ophelia
Published: April 2013

A pair of recently published studies demonstrate that what we happen to be listening to can sometimes change our perception (or, at the very least, our rating) of what we are eating or drinking. In one recent study, North (2012) showed that the emotional attributes (or connotation) of a piece of music could influence people's perception of red or white wine. Meanwhile, Crisinel et al. (2012) reported that listening to a lower-pitched soundscape can help to emphasize the bitter notes in a bittersweet toffee while listening to a soundscape with a higher pitch tends to bring out its sweetness. Although the most appropriate psychological and neuroscientific explanations for such crossmodal effects are still uncertain, we outline a number of possible alternatives for such intriguing, not to mention surprising, phenomena.
Terrestrial cooling in Northern Europe during the Eocene–Oligocene transition
Authors: Hren Michael T. , Sheldon Nathan D. , Grimes Stephen T. , Collinson Margaret E. , Hooker Jerry J. , Bugler Melanie , Lohmann Kyger C.
Published: April 2013

Geochemical and modeling studies suggest that the transition from the “greenhouse” state of the Late Eocene to the “icehouse” conditions of the Oligocene 34–33.5 Ma was triggered by a reduction of atmospheric
p
CO
2
that enabled the rapid buildup of a permanent ice sheet on the Antarctic continent. Marine records show that the drop in
p
CO
2
during this interval was accompanied by a significant decline in high-latitude sea surface and deep ocean temperature and enhanced seasonality in middle and high latitudes. However, terrestrial records of this climate transition show heterogeneous responses to changing
p
CO
2
and ocean temperatures, with some records showing a significant time lag in the temperature response to declining
p
CO
2
. We measured the Δ
47
of aragonite shells of the freshwater gastropod
Viviparus lentus
from the Solent Group, Hampshire Basin, United Kingdom, to reconstruct terrestrial temperature and hydrologic change in the North Atlantic region during the Eocene–Oligocene transition. Our data show a decrease in growing-season surface water temperatures (∼10 °C) during the Eocene–Oligocene transition, corresponding to an average decrease in mean annual air temperature of ∼4–6 °C from the Late Eocene to Early Oligocene. The magnitude of cooling is similar to observed decreases in North Atlantic sea surface temperature over this interval and occurs during major glacial expansion. This suggests a close linkage between atmospheric carbon dioxide concentrations, Northern Hemisphere temperature, and expansion of the Antarctic ice sheets.
Geometric control of vascular networks to enhance engineered tissue integration and function
Authors: Baranski Jan D. , Chaturvedi Ritika R. , Stevens Kelly R. , Eyckmans Jeroen , Carvalho Brian , Solorzano Ricardo D. , Yang Michael T. , Miller Jordan S. , Bhatia Sangeeta N. , Chen Christopher S.
Published: April 2013

Tissue vascularization and integration with host circulation remains a key barrier to the translation of engineered tissues into clinically relevant therapies. Here, we used a microtissue molding approach to demonstrate that constructs containing highly aligned “cords” of endothelial cells triggered the formation of new capillaries along the length of the patterned cords. These vessels became perfused with host blood as early as 3 d post implantation and became progressively more mature through 28 d. Immunohistochemical analysis showed that the neovessels were composed of human and mouse endothelial cells and exhibited a mature phenotype, as indicated by the presence of alpha-smooth muscle actin–positive pericytes. Implantation of cords with a prescribed geometry demonstrated that they provided a template that defined the neovascular architecture in vivo. To explore the utility of this geometric control, we implanted primary rat and human hepatocyte constructs containing randomly organized endothelial networks vs. ordered cords. We found substantially enhanced hepatic survival and function in the constructs containing ordered cords following transplantation in mice. These findings demonstrate the importance of multicellular architecture in tissue integration and function, and our approach provides a unique strategy to engineer vascular architecture.
Rapid cell death is preceded by amyloid plaque-mediated oxidative stress
Authors: Xie Hong , Hou Steven , Jiang Jun , Sekutowicz Maria , Kelly Jonathan , Bacskai Brian J.
Published: April 2013

Neuronal loss is the ultimate outcome in a variety of neurodegenerative diseases and central nerve system disorders. Understanding the sequelae of events that leads to cell death would provide insight into neuroprotective approaches. We imaged neurons in the living brain of a mouse model of Alzheimer’s disease that overexpresses mutant human amyloid precursor protein and presenilin 1 and followed the death of individual neurons in real time. This mouse model exhibited limited neurodegeneration and atrophy, but we were able to identify a small fraction of vulnerable cells that would not have been detectable by using standard approaches. By exploiting a genetically encoded reporter of oxidative stress, we identified susceptible neurons by their increased redox potential. The oxidative stress was most dramatic in neurites near plaques, propagated to cell bodies, and preceded activation of caspases that led to cell death within 24 h. Thus, local oxidative stress surrounding plaques contributes to long-range toxicity and selective neuronal death in Alzheimer’s disease.
A 4-gigabase physical map unlocks the structure and evolution of the complex genome of
Aegilops tauschii,
the wheat D-genome progenitor
Authors: Luo Ming-Cheng , Gu Yong Q. , You Frank M. , Deal Karin R. , Ma Yaqin , Hu Yuqin , Huo Naxin , Wang Yi , Wang Jirui , Chen Shiyong , Jorgensen Chad M. , Zhang Yong , McGuire Patrick E. , Pasternak Shiran , Stein Joshua C. , Ware Doreen , Kramer Melissa , McCombie W. Richard , Kianian Shahryar F. , Martis Mihaela M. , Mayer Klaus F. X. , Sehgal Sunish K. , Li Wanlong , Gill Bikram S. , Bevan Michael W. , Šimková Hana , Doležel Jaroslav , Weining Song , Lazo Gerard R. , Anderson Olin D. , Dvorak Jan
Published: April 2013

The current limitations in genome sequencing technology require the construction of physical maps for high-quality draft sequences of large plant genomes, such as that of
Aegilops tauschii
, the wheat D-genome progenitor. To construct a physical map of the
Ae. tauschii
genome, we fingerprinted 461,706 bacterial artificial chromosome clones, assembled contigs, designed a 10K
Ae. tauschii
Infinium SNP array, constructed a 7,185-marker genetic map, and anchored on the map contigs totaling 4.03 Gb. Using whole genome shotgun reads, we extended the SNP marker sequences and found 17,093 genes and gene fragments. We showed that collinearity of the
Ae. tauschii
genes with
Brachypodium distachyon,
rice, and sorghum decreased with phylogenetic distance and that structural genome evolution rates have been high across all investigated lineages in subfamily Pooideae, including that of Brachypodieae. We obtained additional information about the evolution of the seven Triticeae chromosomes from 12 ancestral chromosomes and uncovered a pattern of centromere inactivation accompanying nested chromosome insertions in grasses. We showed that the density of noncollinear genes along the
Ae. tauschii
chromosomes positively correlates with recombination rates, suggested a cause, and showed that new genes, exemplified by disease resistance genes, are preferentially located in high-recombination chromosome regions.
Broadening the scope of glycosyltransferase-catalyzed sugar nucleotide synthesis
Authors: Gantt Richard W. , Peltier-Pain Pauline , Singh Shanteri , Zhou Maoquan , Thorson Jon S.
Published: April 2013

We described the integration of the general reversibility of glycosyltransferase-catalyzed reactions, artificial glycosyl donors, and a high throughput colorimetric screen to enable the engineering of glycosyltransferases for combinatorial sugar nucleotide synthesis. The best engineered catalyst from this study, the OleD Loki variant, contained the mutations P67T/I112P/T113M/S132F/A242I compared with the OleD wild-type sequence. Evaluated against the parental sequence OleD TDP16 variant used for screening, the OleD Loki variant displayed maximum improvements in
k
cat
/K

m

of >400-fold and >15-fold for formation of NDP–glucoses and UDP–sugars, respectively. This OleD Loki variant also demonstrated efficient turnover with five variant NDP acceptors and six variant 2-chloro-4-nitrophenyl glycoside donors to produce 30 distinct NDP–sugars. This study highlights a convenient strategy to rapidly optimize glycosyltransferase catalysts for the synthesis of complex sugar nucleotides and the practical synthesis of a unique set of sugar nucleotides.