bluuebunny/crossref_metadata_2025 huggingface dataset:
Negative Stains Containing Trehalose: Application to Tubular
and Filamentous Structures
Authors: Harris J. Robin , Gerber Max , Gebauer Wolfgang , Wernicke Wolfgang , Markl Jürgen
Published: April 2013

Several examples are presented that show the successful
application of uranyl acetate and ammonium molybdate negative
staining in the presence of trehalose for TEM studies of
filamentous and tubular structures. The principal benefit to
be gained from the inclusion of trehalose stems from the
considerably reduced flattening of the large tubular structures
and the greater orientational freedom of single molecules due
to an increased depth of the negative stain in the presence
of trehalose. Trehalose is likely to provide considerable
protection to protein molecules and their assemblies during
the drying of negatively stained specimens. Some reduction in
the excessive density imparted by uranyl acetate around large
assemblies is also achieved. Nevertheless, in the presence of
1% (w/v) trehalose, it is desirable to increase the
concentration of negative stain to 5% (w/v) for ammonium
molybdate and to 4% for uranyl acetate to produce satisfactory
image contrast. In general, the ammonium molybdate-trehalose
negative stain is more satisfactory than the uranyl
acetate-trehalose combination, because of the greater electron
beam sensitivity of the uranyl negative stain. Reassembled
taxol-stabilized pig brain microtubules, together with collagen
fibrils, sperm tails, helical filaments, and reassociated
hemocyanin (KLH2), all from the giant keyhole limpet Megathura
crenulata, have been studied by negative staining in the
presence of trehalose. In all cases satisfactory TEM imaging
conditions were readily obtained on the specimens, as long as
regions of excessively deep stain were avoided.
The Use of Backscattered Electron Imaging and Transmission
Electron Microscopy to Assess Bone Architecture and Mineral
Loci: Effect of Intermittent Slow-Release Sodium Fluoride Therapy
Authors: Zerwekh Joseph E. , Bellotto Dennis , Prostak Kenneth S. , Hagler Herbert K. , Pak Charles Y.C.
Published: April 2013

Backscattered electron imaging (BEI) and transmission electron
microscopy (TEM) were used to examine the effects of treatment
with intermittent slow-release sodium fluoride (SRNaF) and
continuous calcium citrate on bone architecture and crystallinity.
Examination was performed in nondecalcified biopsies obtained
from patients following up to four years of therapy (placebo
or SRNaF) and compared to pretreatment biopsies from each patient,
as well as to bone from young, normal subjects. BEI images
disclosed increased areas of recent bone formation following
fluoride administration. There was no evidence of a mineralization
defect in any biopsy and both cortical and trabecular architecture
remained normal. TEM analysis demonstrated intrafibrillar platelike
crystals and extrafibrillar needlelike crystals for both the
pre- and post-treatment biopsies as well as for the bone from
young normal subjects. There was no evidence of increased crystal
size or of an increase in extrafibrillar mineral deposition.
These observations suggest that intermittent SRNaF and continuous
calcium therapy exerts an anabolic action on the skeleton not
accompanied by a mineralization defect or an alteration of bone
mineral deposition. The use of BEI and TEM holds promise for
the study of the pathophysiology and treatment of metabolic
bone diseases.
Fluorescence Microscopy and Fluorescence Probes
Authors: Pawley James B.
Published: April 2013

Fluorescence Microscopy and Fluorescence Probes, edited by
Jan Slavik, 1996. Plenum Press, New York and London. 306 pages. (hardback,
$95)

This volume is a compilation of abstracts of papers presented at the
Fluorescence Microscopy and Fluorescence Probes Conference held in Prague
in June 1995. This conference was one of the first tangible results of the
end of the Cold War in the field of microscopy. As such, it attracted a
great many of those who constitute the vanguard of progress in the field
of fluorescence microscopy, on both sides of the old East-West divide.
About one-third of the 127 contributors were from the West.
The Life and Achievements of John H. Reisner, Ph.D.
Authors: Newberry Sterling P.
Published: April 2013

Electron microscopy recently lost one of its outstanding pioneers when
John Reisner passed away on June 18 of this year. We who have known and
respected John, pause here to remind ourselves of his many contributions
to our field and to visualize for later generations the times and social
forces that brought forth such a remarkable human being. He was remarkable
because of his courageous and skillful management of problems arising from
a severe case of poliomyelitis. He was remarkable because of his
family's determination to help him reach his full potential. He did
in fact lead American development of the electron microscope at RCA from
1950 to 1970 and served (E)MSA in several roles from 1950 on until very
near the end of his life, including as President of the Society.
Calendar of Meetings and Courses
Authors: Reine Barbara , Zaluzec Nestor
Published: April 2013

Following is a list of microscopy-related meetings and courses. The
editors would greatly appreciate input to this list via the electronic
submission form found in the MSA World-Wide Web page at http://
www.msa.microscopy.com/. We will gladly add hypertext links to the
notice on the Web and insert a listing of the meeting in the next issue of
the Journal. Send comments and questions to Barbara Reine,
reine@u.washington.edu or Nestor Zaluzec, zaluzec@aaem.amc.anl.gov.
Calendar of Meetings and Courses
Authors: Reine Barbara , Zaluzec Nestor
Published: April 2013

Following is a list of microscopy-related meetings and courses. The
editors would greatly appreciate input to this list via the electronic
submission form found in the MSA World-Wide Web page at
http://www.msa.microscopy.com/. We will gladly add hypertext
links to the notice on the Web and insert a listing of the meeting in the
next issue of the Journal. Send comments and questions to Barbara Reine,
reine@u.washington.edu or Nestor Zaluzec, zaluzec@aaem.amc.anl.gov.
Microscopy and Microanalysis '98, Atlanta, Georgia
Authors: Alexander Kathi , Jerome Jay
Published: April 2013

Joint meeting of the Microscopy Society of America (56th) and the
Microbeam Analysis Society (32nd).

An exciting and diverse set of meeting activities has been arranged for
the upcoming gathering of microscopists and micro-analysts in Atlanta,
Georgia in July. The meeting should prove to have something for everybody.
The core of the Microscopy and Microanalysis '98 meeting consists of
state-of-the-art symposia in the areas of Advances in Instrumentation and
Techniques and in Applications of Microscopy and Microanalysis in the areas
of biological sciences and physical sciences. Invited speakers include
world-renown researchers from 14 different countries. Of special interest
are symposia celebrating 30 Years of Energy Dispersive Spectrometry in
Microanalysis (specially sponsored by MAS), 30 Years of Atom Probe Field
Ion Microscopy, and a pre-meeting workshop and meeting symposia on that
topic have also been scheduled this year.
Image Formation in Femtosecond Confocal Interference
Microscopy
Authors: Gu Min
Published: April 2013

Three-dimensional image formation in an interference confocal scanning
microscope under ultra-short pulsed beam illumination is investigated in
this study. The novelty of this new image system is that it keeps
advantages in femtosecond interferometry but also provides a
femtosecond-resolved three-dimensional image without necessarily using an
ultrafast detector. For a 5-fs pulsed beam illumination, spatial
resolution in the axial and transverse directions in this system is
improved by approximately 45% and 15%, respectively, compared with that in
the case of continuous wave illumination. However, strong chromatic
aberration caused by an ultrashort pulsed beam can result in a degradation
of spatial and temporal resolution, whereas weak chromatic aberration may
lead to an improvement in transverse resolution.
Simple and Inexpensive Identification of Film Negatives Used in
Light Microscopy
Authors: Koken Marcel H.M.
Published: April 2013

We describe here a simple and inexpensive solution for marking film
negatives with identification numbers before film development. This
technique avoids the purchase of expensive camera-magazines with
data-backs, and it reduces the risk of misidentifying film negatives.
Determination of Myofilament Calcium Distributions from Electron
Probe X-ray Microanalysis Images
Authors: Cantino Marie E. , Eichen Joseph G.
Published: April 2013

The quantity and spatial distribution of calcium bound to myofilaments
is of considerable interest to physiologists studying the regulation of
contraction in striated muscle, but few techniques allow these
distributions to be directly measured. Methods are described here by which
such data can be derived from electron probe X-ray microanalysis (EPXMA)
images. Combination of data from multiple half sarcomeres improves the
signal-to-noise level and allows assessment of variation between half
sarcomeres. Profiles of calcium counts, calcium counts normalized to local
bremstrahlung counts, and calcium counts normalized to the average
bremstrahlung counts for the entire half sarcomere provide differing but
complementary information. Such data help to identify and characterize
spatial variations in Ca binding to regulatory proteins in muscle.
From the Editor
Authors: Johnson Dale E.
Published: April 2013

Dear Colleagues: Please take a moment to read the new Aims and Scope
statement found on page 188. This statement has recently been revised in
response to comments indicating that the previous statement could be
interpreted as not encouraging submission of manuscripts that describe
mainly applications, particularly in the biological fields. That is
clearly not the case, and the Aims and Scope statement has been revised in
this issue to correct that misperception.
High-Temperature In Situ Straining Experiments in the High-Voltage
Electron Microscope
Authors: Messerschmidt Ulrich , Baither Dietmar , Bartsch Martin , Baufeld Bernd , Geyer Bert , Guder Susanne , Wasilkowska Anna , Czyrska-Filemonowicz Aleksandra , Yamaguchi Masaharu , Feuerbacher Michael , Urban Knut
Published: April 2013

Design rules are described here for high-temperature straining stages
for transmission electron microscopy. Temperatures above 1000°C can be
attained by electron bombardment of the specimen grips. Thermal
equilibrium can be reached in a short time by carrying off the heat by
water cooling. Some applications of this stage are described. Ferroelastic
deformation was observed at 1150°C in t′ and partially
stabilized zirconia, which changes the microstructure for successive
dislocation plasticity. In the oxide-dispersion-strengthened alloy INCOLOY
MA 956, dislocations are impeded by oxide particles and move smoothly
between the particles. At high temperatures, both the resting and
traveling times control the average dislocation velocity. In
MoSi2 single crystals of a soft orientation, dislocations with
1/2〈111〉 Burgers vectors are created in localized sources
and move on {110} planes in a viscous manner. The dislocations
in Al-Pd-Mn single quasicrystals are oriented in preferred
crystallographic directions and move in a viscous way as well. On the
basis of in situ observations, conclusions are drawn for interpreting
macroscopic deformation behavior at high temperatures.
In Situ Transmission Electron Microscope Observation of Melting of
Aluminum Particles
Authors: Arai S. , Tsukimoto S. , Saka H.
Published: April 2013

The processes of melting and freezing of aluminum (Al) particles have
been observed directly in a transmission electron microscope. The liquid
phase nucleated preferentially at the surface of an Al particle,
surrounding the crystalline solid at the onset of melting. The liquid
phase then propagated inside the Al particle at the expense of the
solid.
Surface Reconstruction and Oxide Nucleation Due to Oxygen
Interaction with Cu(001) Observed by In Situ Ultra-High Vacuum
Transmission Electron Microscopy
Authors: Yang Judith C. , Yeadon Mark , Kolasa Borys , Gibson J. Murray
Published: April 2013

Reconstruction of the Cu(001) surface due to oxygen gas impingement on
a clean copper surface was directly observed by in situ UHV-TEM. Strain
contrast between differently oriented surface reconstruction domains,
assumed to be √2 × 2√2 R45, were clearly visible by this
method. The reconstruction precedes the nucleation of Cu2O
islands. When Cu2O islands were partially reduced and then
re-oxidized, a dwell time before formation of Cu2O was noted,
demonstrating that a reconstructed Cu-O surface monolayer is necessary
before oxide formation.
Advances in Imaging and Electron Physics, Volume 101, Edited by P.W. Hawkes
1998. Academic Press, San Diego. 244 pages. (hardback, $130)
Authors: Tivol William F.
Published: April 2013

This volume comprises four articles on widely divergent
topics and of equally divergent practicality. The first article,
by P.E. Champness, is on the application of transmission
electron microscopy to mineralogy; analytical electron microscopy
and high-resolution transmission electron microscopy
are discussed. If you are a mineralogist who is interested
in the kinds of results these techniques can provide, or
if you are an expert in transmission electron microscopy
who wants to drum up business from the geology department
in your institution, you will find useful information
here.
Empirical Identification of Uranium Oxides and Fluorides Using Electron Energy-loss Spectroscopy in the Transmission Electron Microscope
Authors: Rice Stephen B. , Bales Hazel H. , Roth John R. , Whiteside Allen L.
Published: April 2013

Abstract: A set of uranium compound particles relevant to contaminated soils and other environmental concerns surrounding uranium bioavailability were studied by electron energy-loss spectroscopy (EELS). Core-loss EELS results suggest that uranium 4+ compounds have an energy loss resolvable from 6+ compounds. Shoulders on the uranium O4,5 edge further distinguish UO2 from UF4. Low-loss characteristics distinguish carbon-free uranium oxide specimens on holey substrates. In the presence of carbon, correction techniques must be applied. Uranium oxides, fluorides, and minerals show a tendency toward reduction of uranium toward 4+ under the beam. The electron dose required to achieve the transformation from 6+ to 4+ is more severe than that usually required to obtain satisfactory spectra, but the possibility for reduction should be considered. The conditions for low-loss analysis need not be as vigorous as those for core losses, and can be done without altering the valence of most oxides.
Transmission Electron Microscopy Characterization and Application of Sol-Gel Membranes
Authors: Guo Yizhu , Gonzalez Sandra , Guadalupe Ana R.
Published: April 2013

Abstract: Using standard square mesh grids as supports, we have prepared sol-gel membranes from a functionalized silane precursor, bis[3-(triethoxysilyl)propyl]tetrasulfide in various organic solvents. These mesh-supported membranes allow direct characterization of their microstructure and morphology by transmission electron microscopy (TEM). Homogeneous membranes without prominent microstructural features (or featureless) at nanometer scale were obtained from dimethyl formamide (DMF), isopropanol, and butanol solutions. However, highly porous membranes were produced from DMF and ethylene glycol binary system. Heterogeneous membranes filled with nanoparticles were formed from dimethyl sulfoxide solution. The featureless sol-gel membranes with tunable performances provide a useful alternative as supporting films for TEM applications.
A quality review of the occurrence of a non-fatal venous air embolism event following CT contrast enhanced administration for the purpose of radiation therapy planning
Authors: Bayliss Y. , Balogh A. , Burrowes P. , Brunet G. , Jensen K.
Published: April 2013

Background

The incidence of venous air embolism (VAE) during and following diagnostic and interventional radiographic procedures utilizing contrast media has been well documented in the literature. However to date a case report of a venous air embolism occurring within an outpatient healthcare facility during a contrast enhanced computer tomography radiation therapy planning procedure remains under reported.

Purpose

Healthcare professionals must remain alerted to the fact that iatrogenic VAE may occur unexpectedly during and following diagnostic and interventional radiographic procedures utilizing the injection of contrast media. The action by all healthcare professionals to implement rapid and clear acute care guidelines will increase the probability of the patient recovering from the event.

Materials and methods

A review of the aetiology and associated pathophysiology of VAE is provided. This is followed by a detailed case report of the occurrence of a non-fatal VAE event (patient consent was obtained and the consent form template was reviewed by a Research Ethics Board).

Conclusion

We conclude with a discussion of quality assurance recommendations that should be considered for implementation in an outpatient facility setting that is performing contrast enhanced computer tomography diagnostic, interventional or radiation therapy planning radiographic procedures.
Calculation of planning margins for different verification techniques in radical prostate radiotherapy
Authors: Gleeson Ian
Published: April 2013

Purpose

To calculate and compare planning target volume (PTV) margins for an offline 3 mm tolerance, daily bony anatomy verification, tattoo alignment and online prostate marker matching with those currently used at our institution.

Methods

Seventy patients had offline bony anatomy megavoltage verification. 23 different patients underwent fiducial marker matching using daily online kilovoltage verification. Systematic and random errors were measured in the right–left (RL), superior–inferior (SI) and anterior–posterior (AP) directions. Geometric uncertainties from literature were used to help calculate the margins.

Results

PTV margins (mm) were 7 RL, 12 SI and AP (3 mm tolerance offline bony), 6 RL, 11 SI and AP (daily online bony), 8 RL, 12 SI and AP (tattoo alignment) and 5 RL, 8 SI and 6 AP (online daily prostate marker correction).

Conclusions

Our current margins for conformal radiotherapy patients are too small for phase 2 in the SI and AP directions. Implementing online daily bony anatomy matching would not reduce the PTV margin significantly. Online daily marker correction showed current PTV71 Gy margins as excessive by (mm) 5 RL, 2 SI and 4 anterior.
A 2-bit, 3.1 GS/s, band-pass DSM receiver for active antenna systems
Authors: Karthaus Udo , Ahles Stephan , Elmaghraby Ahmed , Wagner Horst
Published: April 2013

This paper presents a radio frequency (RF) continuous-time band-pass delta sigma modulator (CT BP DSM) receiver realized in a 180 nm SiGe BiCMOS technology. It also provides an introduction to active antenna systems (AAS) for cellular infrastructure base stations, which is the target application for this RF integrated circuit (IC). The internal quantizer and feedback digital to analog converter (DAC) resolution of the CT BP DSM is 2 bit. Without applying DAC linearization techniques such as trimming or dynamic element matching being utilized, measured performance parameters include an SNR and SNDR in 35 MHz bandwidth of 56.7 and 53.7 dB, respectively. IIP3 and noise figure are −6.6 dBm and 10 dB, respectively. No image reception is noticeable within a measurement dynamic range of 83 dB. When driven by single-carrier and three-carrier W-CDMA signals, adjacent channel leakage ratio (ACLR) is −62.6 and −52.1 dB, respectively, making the design also suitable as a modulator for a class-S power amplifier.
Position estimation of lap joints for seam tracking applications at mm-wave frequencies
Authors: Schrattenecker Jochen O. , Haderer Andreas , Reinthaler Günther , Stelzer Andreas
Published: April 2013

In this paper, we present the results of using a frequency-stepped continuous-wave radar system to estimate the position of overlapping and electrically good conductive plates. We especially focus on polarimetric scattering effects caused by the step of a lap joint, which is a common welding-geometry. To model the step's contribution to the overall scattered signal, we use a two-dimensional combined field integral equation (CFIE) approach. For demonstrating its practical applicability, the implemented scattering model is verified by measurements. To emphasize the improvements of position estimation by using a CFIE approach, the outcomes of the model are compared to a commonly used point scattering model. Finally, the numerical signal is utilized to precisely estimate the position of the lap joint.
Study of the noise processes in microwave oscillators based on passive optical resonators
Authors: Saleh Khaldoun , Merrer Pierre-Henri , Ali-Slimane Amel , Llopis Olivier , Cibiel Gilles
Published: April 2013

Two types of optoelectronic oscillators delivering high spectral purity microwave signals are presented in this paper. These oscillators use the Pound–Drever–Hall laser stabilization technique to lock the laser carrier onto two different types of passive optical resonators featuring high-quality factors: a fiber ring resonator (FRR) and a whispering gallery mode monocrystalline disk-shaped micro-resonator. The different noise processes occurring inside these oscillators are discussed. Particular attention is given to the conversion of the laser's amplitude and frequency noise into RF phase noise via the laser stabilization loop and the resonator, and via the photodetector nonlinearity as well. A modeling approach using CAD software is also proposed to qualitatively evaluate laser noise conversion through the optical resonator. Moreover, different contributions of nonlinear optical scattering noise are discussed, mainly in the case of the FRR-based oscillator. When controlling these nonlinear optical effects in the case of the FRR, low-phase noise operation of the oscillator has been achieved, with a −40 dBc/Hz noise level at 10 Hz offset frequency from a 10.2 GHz RF carrier.
A 24 GHz wideband monostatic FMCW radar system based on a single-channel SiGe bipolar transceiver chip
Authors: Bredendiek Christian , Pohl Nils , Jaeschke Timo , Thomas Sven , Aufinger Klaus , Bilgic Attila
Published: April 2013

In this paper a monostatic frequency-modulated continuous-wave (FMCW) radar system around a center frequency of 24 GHz with a wide tuning range of 8 GHz (≈33%) is presented. It is based on a fully integrated single-channel SiGe transceiver chip. The chip architecture consists of a fundamental VCO, a receive mixer, a divider chain, and coupling/matching networks. All circuits, except for the divider, are designed with the extensive use of on-chip monolithic integrated spiral inductors. The chip is fabricated in a SiGe bipolar production technology which offers an fT of 170 GHz and fmax of 250 GHz. The phase noise at 1 MHz offset is better than −100 dBc/Hz over the full-tuning range of 8 GHz and a phase noise of better than −111 dBc/Hz is achieved at 27 GHz. The peak output power of the chip is −1 dBm while the receive mixer offers a 1 dBm input referred compression point to keep it from being saturated. The chip has a power consumption of 245 mW and uses an area of 1.51 mm2. The FMCW radar system achieves a power consumption below 1.6 W. Owing to the high stability of the sensor, high accuracy mesaurements with a range error <±250 µm were achieved. The standard deviation between repeated measurements of the same target is 0.6 µm and the spatial resolution is 28 mm.
Lerntransfer
Authors: Marschelke Ekkehard
Published: April 2013

Lernen bis zur beruflichen Handlungsfähigkeit (Basiskompetenz, Leistungskompetenz) stützt sich insbesondere auf zwei Methoden des Lerntransfers. Die eine zielt auf die Umsetzung von beruflichem Wissen in berufliches Handeln (Theorie in Praxis), die andere auf die Umsetzung von Erfahrungen in Routinen und Repertoire für die Arbeit (Professionalisierung). Muss man Schülern diese Methoden beibringen? Oder geht das ganz anders?
Interprofessionelles Lehren und Lernen
Authors: Koch Lee F. , Horn Helga
Published: April 2013

Was ist interprofessionelles Lernen und warum sollten Auszubildende in den pflegerischen, therapeutischen, medizinischen und sozialen Berufen gemeinsam lernen? Der Beitrag beleuchtet Chancen und Hindernisse berufsübergreifender Ausbildungsstrukturen.
Anrechnung pflegeberuflicher Kompetenzen auf ein Studium
Authors: Kimmerle Birte , Bertsch Bianca , Riedel Annette , Bonse-Rohmann Mathias
Published: April 2013

Im Projekt „Anrechnung pflegeberuflicher Kompetenzen auf Bachelor-Studiengänge“ wurde untersucht, inwieweit berufliche Kompetenzen aus Berufsausbildungen der Pflege auf ein Pflegestudium angerechnet werden können. Der Beitrag stellt ein Verfahren zur Anrechnung pflegeberuflich erworbener Kompetenzen auf Pflegestudiengänge vor, das im Rahmen eines Forschungsprojektes in Kooperation mit sechs regionalen Bildungseinrichtungen entwickelt und erprobt hat.
Challenges and Opportunities for Suicide Bereavement Research
Authors: Moore Melinda , Maple Myfanwy , Mitchell Ann M. , Cerel Julie
Published: April 2013

Background: While high-quality and ethically sound research is needed to better understand and respond to the needs of those bereaved by suicide, there is a concern that ethical boards internationally raise unreasonable objections to research with those bereaved by suicide. Aims: This pilot study was conducted to examine the issues faced by suicide bereavement and postvention researchers while obtaining ethical board approval. Method: Suicide bereavement and postvention researchers from four continents were surveyed on their experiences of responding to ethical board challenges to research proposals and requests to amend their research as a result of ethical board concerns. Results: While ethical boards differ in their response to suicide bereavement research, eight of 19 researchers surveyed indicated they had had proposals challenged, with two of these eight researchers reporting having to make major changes to their proposals as a result. The researchers provided examples of how they responded to those concerns about perceived risks of their research by ethical board members. Conclusions: There are strict guidelines regarding the treatment of research study participants, and ethical boards must ensure the proposed research procedures adhere to these guidelines. Yet, in the field of suicide bereavement research it would appear that some ethical boards place restrictions or raise concerns about research being conducted in an absence of sound knowledge about the safety of such research. This ultimately may influence the design of research being conducted. Such influence in turn shapes the data generated from the research and thus what is published in the literature. It is both timely and imperative for ethical board members to be well educated on what the risks of those who are bereaved by suicide may be prior to making recommendations on research project designs.
βTrCP interacts with the ubiquitin-dependent endocytosis motif of the GH receptor in an unconventional manner
Authors: da Silva Almeida Ana C. , Hocking Henry G. , Boelens Rolf , Strous Ger J. , van Rossum Agnes G. S. H.
Published: April 2013

GH (growth hormone) binding to the GHR (GH receptor) triggers essential signalling pathways that promote growth and metabolic regulation. The sensitivity of the cells to GH is mainly controlled by the endocytosis of the receptor via βTrCP (β-transducin repeat-containing protein). In the present study, we show that βTrCP interacts directly via its WD40 domain with the UbE (ubiquitin-dependent endocytosis) motif in GHR, promoting GHR ubiquitination in vitro. NMR experiments demonstrated that the UbE motif is essentially unstructured, and, together with functional mapping of the UbE and βTrCP WD40 residues necessary for binding, led to a unique interaction model of βTrCP with GHR–UbE. This interaction is different from the conventional βTrCP–substrate interactions described to date. This interaction therefore represents a promising specific target to develop drugs that inhibit GHR endocytosis and increase GH sensitivity in cachexia patients.
Polysialic and colanic acids metabolism in Escherichia coli K92 is regulated by RcsA and RcsB
Authors: Navasa Nicolás , Rodríguez-Aparicio Leandro , Ferrero Miguel Ángel , Monteagudo-Mera Andrea , Martínez-Blanco Honorina
Published: April 2013

We have shown previously that Escherichia coli K92 produces two different capsular polymers known as CA (colanic acid) and PA (polysialic acid) in a thermoregulated manner. The complex Rcs phosphorelay is largely related to the regulation of CA synthesis. Through deletion of rscA and rscB genes, we show that the Rcs system is involved in the regulation of both CA and PA synthesis in E. coli K92. Deletion of either rcsA or rcsB genes resulted in decreased expression of cps (CA biosynthesis cluster) at 19°C and 37°C, but only CA production was reduced at 19°C. Concerning PA, both deletions enhanced its synthesis at 37°C, which does not correlate with the reduced kps (PA biosynthesis cluster) expression observed in the rcsB mutant. Under this condition, expression of the nan operon responsible for PA catabolism was greatly reduced. Although RcsA and RcsB acted as negative regulators of PA synthesis at 37°C, their absence did not reestablish PA expression at low temperatures, despite the deletion of rcsB resulting in enhanced kps expression. Finally, our results revealed that RcsB controlled the expression of several genes (dsrA, rfaH, h-ns and slyA) involved in the thermoregulation of CA and PA synthesis, indicating that RcsB is part of a complex regulatory mechanism governing the surface appearance in E. coli.
Generation of high-quality mega-electron volt proton beams with intense-laser-driven nanotube accelerator
Authors: Murakami M. , Tanaka M.
Published: April 2013

An ion acceleration scheme using carbon nanotubes (CNTs) is proposed, in which embedded fragments of low-Z materials are irradiated by an ultrashort intense laser to eject substantial numbers of electrons. Due to the resultant characteristic electrostatic field, the nanotube and embedded materials play the roles of the barrel and bullets of a gun, respectively, to produce highly collimated and quasimonoenergetic ion beams. Three-dimensional particle simulations, that take all the two-body Coulomb interactions into account, demonstrate generation of quasimonoenergetic MeV-order proton beams using nanometer-size CNT under a super-intense electrostatic field ∼1014 V m−1.
A transition in the nature of the occupancy of the dislocation lines within n-type wurtzite gallium nitride
Authors: Baghani Erfan , O'Leary Stephen K.
Published: April 2013

Within the framework of the model of Read [Philos. Mag. 45, 775 (1954)], we examine the occupancy of the dislocation lines within n-type wurtzite gallium nitride. In particular, we examine the transition that occurs as the bulk doping concentration is increased, from the depletion limit to the non-depletion limit. We note that an abrupt transitional bulk doping concentration can be defined. The dependence of this transitional bulk doping concentration on the dislocation line density is then determined. We note that existing theoretical results on the occupation statistics of the threading dislocation lines within wurtzite gallium nitride also exhibit such a transition. Since these theoretical results assume different structures for the core of the threading dislocation lines, we conclude that this transition between the depletion and non-depletion domains should be a universal feature, holding true irrespective of the particular structure being assumed for the core of the threading dislocation lines. Conditions under which this abrupt transition smoothens are also discussed.
Three-dimensional graphene foam-based transparent conductive electrodes in GaN-based blue light-emitting diodes
Authors: Kim Byung-Jae , Yang Gwangseok , Joo Park Min , Seop Kwak Joon , Hyeon Baik Kwang , Kim Donghwan , Kim Jihyun
Published: April 2013

We demonstrated three-dimensional (3D) graphene foam-based transparent conductive electrodes in GaN-based blue light-emitting diodes (LEDs). A 3D graphene foam structure grown on 3D Cu foam using a chemical vapor deposition method was transferred onto a p-GaN layer of blue LEDs. Optical and electrical performances were greatly enhanced by employing 3D graphene foam as transparent conductive electrodes in blue LED devices, which were analyzed by electroluminescence measurements, micro-Raman spectroscopy, and light intensity-current-voltage testing. The forward operating voltage and the light output power at an injection current of 100 mA of the GaN-based blue LEDs with a graphene foam-based transparent conductive electrode were improved by ∼26% and ∼14%, respectively. The robustness, high transmittance, and outstanding conductivity of 3D graphene foam show great potentials for advanced transparent conductive electrodes in optoelectronic devices.
Full counting statistics of stationary particle beams
Authors: Kiukas J. , Ruschhaupt A. , Werner R. F.
Published: April 2013

We present a general theoretical framework for treating particle beams as time-stationary limits of many particle systems. Due to stationarity, the total particle number diverges, and a description in Fock space is no longer possible. Nevertheless, we show that when describing the particle detection via second quantized arrival time observables, such beams exhibit a well-defined “local” counting statistics, that is, full counting statistics of all clicks falling into any given finite time interval. We also treat in detail a realization of such a beam via the long time limit of a source creating particles in a fixed initial state from which they then evolve freely. From the mathematical point of view, the beam is described by a quasi-free state which, in the one-particle level, is locally trace class with respect to the operator valued measure describing the time observable; this ensures the existence of a Fredholm determinant defining the characteristic function of the counting statistics.
A maximum-entropy approach to the adiabatic freezing of a supercooled liquid
Authors: Prestipino Santi
Published: April 2013

I employ the van der Waals theory of Baus and co-workers to analyze the fast, adiabatic decay of a supercooled liquid in a closed vessel with which the solidification process usually starts. By imposing a further constraint on either the system volume or pressure, I use the maximum-entropy method to quantify the fraction of liquid that is transformed into solid as a function of undercooling and of the amount of a foreign gas that could possibly be also present in the test tube. Upon looking at the implications of thermal and mechanical insulation for the energy cost of forming a solid droplet within the liquid, I identify one situation where the onset of solidification inevitably occurs near the wall in contact with the bath.
Boiling heat transfer enhancement of magnetically actuated nanofluids
Authors: Şeşen Muhsincan , Tekşen Yiğit , Şahin Berna , Şendur Kürşat , Pınar Mengüç M. , Koşar Ali
Published: April 2013

Nanofluids offer a potential breakthrough as next-generation heat transfer fluids since they offer exciting new possibilities to enhance heat transfer performance compared to pure liquids. A major drawback for using nanofluids in practical applications is difficulty in maintaining their stability due to deposition on surfaces. In this study, we propose and experimentally investigate a magnetic actuation scheme to avoid this deposition. Two-phase heat transfer characteristics of the designed system have been experimentally investigated with magnetic actuation and compared to the results without magnetic actuation. Two phase average heat transfer enhancement observed with the suggested system was 17%. The average single phase enhancement is found as 29% with magnetic actuation. It was observed that magnetically actuated nanoparticles neither form any clusters nor precipitate after the experiments.
A simple high-voltage high current spark gap with subnanosecond jitter triggered by femtosecond laser filamentation
Authors: Arantchouk L. , Houard A. , Brelet Y. , Carbonnel J. , Larour J. , André Y.-B. , Mysyrowicz A.
Published: April 2013

We describe a simple, sturdy, and reliable spark gap operating with air at atmospheric pressure and able to switch currents in excess of 10 kA with sub-nanosecond jitter. The spark gap is remotely triggered by a femtosecond laser filament.
Optical control of individual carbon nanotube light emitters by spectral double resonance in silicon microdisk resonators
Authors: Imamura S. , Watahiki R. , Miura R. , Shimada T. , Kato Y. K.
Published: April 2013

We demonstrate integration of individual light-emitting carbon nanotubes with silicon microdisk resonators. Photons emitted from nanotubes are efficiently coupled to whispering gallery modes, circulating within the disks and lighting up their perimeters. Furthermore, we control such emission by tuning the excitation wavelength in and out of resonance with higher order modes in the same disk. Our results open up the possibilities of using nanotube emitters embedded in photonic circuits that are individually addressable through spectral double resonance.
Room-temperature thermally induced relaxation effect in a two-dimensional cyano-bridged Cu-Mo bimetal assembly and thermodynamic analysis of the relaxation process
Authors: Umeta Yoshikazu , Tokoro Hiroko , Ozaki Noriaki , Ohkoshi Shin-ichi
Published: April 2013

We observed a photo-switching effect in [CuII(1,4,8,11-tetraazacyclodecane)]2[MoIV(CN)8]·10H2O by irradiation with 410-nm light around room temperature using infrared spectroscopy. This photo-switching is caused by the photo-induced charge transfer from MoIV to CuII. The photo-induced phase thermally relaxed to the initial phase with a half-life time of 2.7 × 101, 6.9 ×101, and 1.7 × 102 s at 293, 283, and 273 K, respectively. The relaxation process was analyzedusing Hauser's equation, k =k0exp[−(Ea +Ea*γ) /kBT], where k is the rate constant of relaxation, k0 is the frequency factor, Eais the activation energy,Ea* is the additional activation energy due to the cooperativity,and γ is the fraction of the photo-induced phase. k0, Ea, and Ea* were evaluated as 1.28 × 107 ± 2.6 s−1, 4002 ± 188 cm−1, and 546 ± 318 cm−1, respectively. The value of Ea is much larger than that of the relaxation process for the typical light-induced spin crossover effect (Ea ≈1000 cm−1). Room-temperature photo-switching is an important issue in the field of optical functional materials. The present system is useful for the demonstration of high-temperature photo-switching material.
Weak Priors versus Overfitting of Predictions in Autism: Reply to Pellicano and Burr (TICS, 2012)
Authors: Van de Cruys Sander , de-Wit Lee , Evers Kris , Boets Bart , Wagemans Johan
Published: April 2013

Pellicano and Burr (2012) argue that a Bayesian framework can help us understand the perceptual peculiarities in autism. We agree, but we think that their assumption of uniformly flat or equivocal priors in autism is not empirically supported. Moreover, we argue that any full account has to take into consideration not only the nature of priors in autism, but also how these priors are constructed or learned. We argue that predictive coding provides a more constrained framework that very naturally explains how priors are constructed in autism leading to strong, but overfitted, and non-generalizable predictions.
Inferred Motion Perception of Light Sources in 3D Scenes is Color-Blind
Authors: Gerhard Holly E. , Maloney Laurence T.
Published: April 2013

In everyday scenes, the illuminant can vary spatially in chromaticity and luminance, and change over time (e.g. sunset). Such variation generates dramatic image effects too complex for any contemporary machine vision system to overcome, yet human observers are remarkably successful at inferring object properties separately from lighting, an ability linked with estimation and tracking of light field parameters. Which information does the visual system use to infer light field dynamics? Here, we specifically ask whether color contributes to inferred light source motion. Observers viewed 3D surfaces illuminated by an out-of-view moving collimated source (sun) and a diffuse source (sky). In half of the trials, the two sources differed in chromaticity, thereby providing more information about motion direction. Observers discriminated light motion direction above chance, and only the least sensitive observer benefited slightly from the added color information, suggesting that color plays only a very minor role for inferring light field dynamics.
Soluble IL7Rα potentiates IL-7 bioactivity and promotes autoimmunity
Authors: Lundström Wangko , Highfill Steven , Walsh Scott T. R. , Beq Stephanie , Morse Elizabeth , Kockum Ingrid , Alfredsson Lars , Olsson Tomas , Hillert Jan , Mackall Crystal L.
Published: April 2013

Significance

Many genes have been shown to influence the risk of developing multiple sclerosis (MS); however, the biological processes responsible are not clear. We found that a genetic polymorphism associated with increased MS risk is responsible for potentiating the effects of a cytokine named interleukin (IL)-7 by securing its availability and bioactivity over time. This effect was mediated by an isoform of the IL-7 receptor that circulates at high levels in blood. IL-7 is an important factor for T-cell maturation and proliferation, and, hence, its association to MS, which is an autoimmune disease, is not surprising.
Benefit of pulsation in soft corals
Authors: Kremien Maya , Shavit Uri , Mass Tali , Genin Amatzia
Published: April 2013

Soft corals of the family Xeniidae exhibit a unique, rhythmic pulsation of their tentacles (
Movie S1
), first noted by Lamarck nearly 200 y ago. However, the adaptive benefit of this perpetual, energetically costly motion is poorly understood. Using in situ underwater particle image velocimetry, we found that the pulsation motions thrust water upward and enhance mixing across the coral–water boundary layer. The induced upward motion effectively prevents refiltration of water by neighboring polyps, while the intensification of mixing, together with the upward flow, greatly enhances the coral’s photosynthesis. A series of controlled laboratory experiments with the common xeniid coral
Heteroxenia fuscescens
showed that the net photosynthesis rate during pulsation was up to an order of magnitude higher than during the coral’s resting, nonpulsating state. This enhancement diminished when the concentration of oxygen in the ambient water was artificially raised, indicating that the enhancement of photosynthesis was due to a greater efflux of oxygen from the coral tissues. By lowering the internal oxygen concentration, pulsation alleviates the problem of reduced affinity of ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO) to CO
2
under conditions of high oxygen concentrations. The photosynthesis–respiration ratio of the pulsating
H. fuscescens
was markedly higher than the ratios reported for nonpulsating soft and stony corals. Although pulsation is commonly used for locomotion and filtration in marine mobile animals, its occurrence in sessile (bottom-attached) species is limited to members of the ancient phylum Cnidaria, where it is used to accelerate water and enhance physiological processes.
Bats are a major natural reservoir for hepaciviruses and pegiviruses
Authors: Quan Phenix-Lan , Firth Cadhla , Conte Juliette M. , Williams Simon H. , Zambrana-Torrelio Carlos M. , Anthony Simon J. , Ellison James A. , Gilbert Amy T. , Kuzmin Ivan V. , Niezgoda Michael , Osinubi Modupe O. V. , Recuenco Sergio , Markotter Wanda , Breiman Robert F. , Kalemba Lems , Malekani Jean , Lindblade Kim A. , Rostal Melinda K. , Ojeda-Flores Rafael , Suzan Gerardo , Davis Lora B. , Blau Dianna M. , Ogunkoya Albert B. , Alvarez Castillo Danilo A. , Moran David , Ngam Sali , Akaibe Dudu , Agwanda Bernard , Briese Thomas , Epstein Jonathan H. , Daszak Peter , Rupprecht Charles E. , Holmes Edward C. , Lipkin W. Ian
Published: April 2013

Although there are over 1,150 bat species worldwide, the diversity of viruses harbored by bats has only recently come into focus as a result of expanded wildlife surveillance. Such surveys are of importance in determining the potential for novel viruses to emerge in humans, and for optimal management of bats and their habitats. To enhance our knowledge of the viral diversity present in bats, we initially surveyed 415 sera from African and Central American bats. Unbiased high-throughput sequencing revealed the presence of a highly diverse group of bat-derived viruses related to hepaciviruses and pegiviruses within the family
Flaviridae
. Subsequent PCR screening of 1,258 bat specimens collected worldwide indicated the presence of these viruses also in North America and Asia. A total of 83 bat-derived viruses were identified, representing an infection rate of nearly 5%. Evolutionary analyses revealed that all known hepaciviruses and pegiviruses, including those previously documented in humans and other primates, fall within the phylogenetic diversity of the bat-derived viruses described here. The prevalence, unprecedented viral biodiversity, phylogenetic divergence, and worldwide distribution of the bat-derived viruses suggest that bats are a major and ancient natural reservoir for both hepaciviruses and pegiviruses and provide insights into the evolutionary history of hepatitis C virus and the human GB viruses.
Control of cell proliferation, endoreduplication, cell size, and cell death by the retinoblastoma-related pathway in maize endosperm
Authors: Sabelli Paolo A. , Liu Yan , Dante Ricardo A. , Lizarraga Lucina E. , Nguyen Hong N. , Brown Sara W. , Klingler John P. , Yu Jingjuan , LaBrant Evan , Layton Tracy M. , Feldman Max , Larkins Brian A.
Published: April 2013

Significance

Cereal endosperm is a key source of dietary calories and raw materials for countless manufactured goods. Understanding how the cell cycle is regulated during endosperm development could lead to increased crop yield. We show that a maize
Retinoblastoma
-related gene,
RBR1
, plays a central role in regulating gene expression, endoreduplication, and the number, size, and death of endosperm cells.
RBR1
is genetically coupled to
Cyclin Dependent Kinase A;1
in controlling endoreduplication but not gene expression. Seeds down-regulated for
RBR1
develop normally, which suggests higher-order control mechanisms regulating endosperm development that are superimposed on cell cycle regulation.
The Music Collection of Thomas Baker of Farnham, Surrey
Authors: Martin Cheryl
Published: April 2013

Thomas Baker's music collection is part of the special collections of the Music Library at Western University, Ontario. Thomas Baker (1719/20–94) lived mainly in Farnham, southwest of London, England, in the County of Surrey. His music collection remained largely intact, which is unusual for the library of an eighteenth-century man who lived in a small town in rural England. The collection at Western consists of 90 separate pieces of music, collections of music, and books of music theory, plus six manuscripts; an inventory of the collection illustrates the variety of musical forms that he collected. His purchase of an organ leads us to conclude that he played the organ and possibly other keyboard instruments; about 25% of his collection is for keyboard. However, he was also interested in a variety of other musical forms, either as a performer or as a collector. From the surviving information, we can create a basic portrait of Baker and his music collection, even if we can draw no definite conclusions about how it was used or if he was merely a collector, or also a performer or an organizer of concerts.