bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of a spinifex‐textured basalt as an analog to Gusev crater basalts, Mars
Authors: BOST Nicolas , WESTALL Frances , GAILLARD Fabrice , RAMBOZ Claire , FOUCHER Frédéric
Published: May 2012

Abstract– Analyses by the Mars Exploration Rover (MER), Spirit, of Martian basalts from Gusev crater show that they are chemically very different from terrestrial basalts, being characterized in particular by high Mg‐ and Fe‐contents. To provide suitable analog basalts for the International Space Analogue Rockstore (ISAR), a collection of analog rocks and minerals for preparing in situ space missions, especially, the upcoming Mars mission MSL‐2011 and the future international Mars‐2018 mission, it is necessary to synthesize Martian basalts. The aim of this study was therefore to synthesize Martian basalt analogs to the Gusev crater basalts, based on the geochemical data from the MER rover Spirit. We present the results of two experiments, one producing a quench‐cooled basalt (<1 h) and one producing a more slowly cooled basalt (1 day). Pyroxene and olivine textures produced in the more slowly cooled basalt were surprisingly similar to spinifex textures in komatiites, a volcanic rock type very common on the early Earth. These kinds of ultramafic rocks and their associated alteration products may have important astrobiological implications when associated with aqueous environments. Such rocks could provide habitats for chemolithotrophic microorganisms, while the glass and phyllosilicate derivatives can fix organic compounds.
New insights into the formation of fayalitic olivine from Allende dark inclusions
Authors: VARELA Maria E. , ZINNER Ernst , KURAT Gero , CHU Hao‐Tsu , HOPPE Peter
Published: May 2012

Abstract–Although considerable progress has been made in unraveling the origin(s) of fayalitic olivines in dark inclusions (DIs), many questions remain still unresolved and/or controversial. We combine a chemical and petrographic study of the Allende dark inclusion 4884‐2B (AMNH, New York) and ATEM studies of a fragment of the dark inclusion Allende AF (NHM, Vienna) and discuss an alternative way in which fayalitic olivines could have formed. Allende dark inclusion 4884‐2B contains a few aggregates with variable proportions of transparent and feathery olivine. Two such objects (aggregates A and B) are the focus of this study as they preserve glasses that can help in deciphering the nature of the processes involved during olivine growth and subsequent olivine transformation. The petrographic and chemical characteristics of aggregates A and B indicate that the forsteritic stack olivines may be pseudomorphs of clear olivine crystals. The ATEM studies in All‐AF suggest that fayalitic olivines may be the result of secondary processes (e.g., metasomatic exchange reactions) operating in the solar nebula. Transformation may have occurred through the mediation of a dry gas phase involving nonvolatile major elements, such as Mg and Fe (e.g.,Dohmen et al. 1998). This mechanism could reveal olivine growth patterns (e.g., stacked platelets due to a rapid growth regime) and may have contributed to the development of their fibrous aspect while preserving the shape (i.e., volume) of the crystals. This highly selective process did completely or partially transform ferromagnesian minerals, but affected the fine‐grained mesostasis only slightly.
Synthesis and Structural Probing of Eu3+ Doped BaYF5 Nano‐Crystals in Transparent Oxyfluoride Glass‐Ceramics
Authors: Biswas Kaushik , Sontakke Atul D. , Annapurna Kalyandurg
Published: May 2012

Transparent oxyfluoride glass‐ceramics containing Eu: BaYF5 nano‐crystals in the newly developed SiO2–K2CO3–BaF2–YF3–Sb2O3 glass system are synthesized by melt quenching method followed by optimized ceramization process. The X‐ray diffraction, transmission electron microscopy, and field emission scanning electron microscopy confirmed the precipitation of tetragonal BaYF5 nano‐crystals in glass matrix. The coexistence of Eu2+ and Eu3+ ions in both glass and glass‐ceramics are ascertained from their emission and excitation spectra. The in situ formation of divalent europium (Eu2+) along with Eu3+ during high temperature synthesis under ambient atmosphere is explained through optical basicity model. The Eu3+ emission from upper excitation states (5D3−1) and reduced asymmetry ratio (R = IED/IMD) in glass‐ceramics have established the dopant ion incorporation into fluoride nano‐crystalline environment. The observed luminescence properties of Eu:BaYF5 are compared with that of Eu:BaYF5 nanocrystals containing transparent glass‐ceramics and their marked differences are discussed.
Hierarchical analysis of spatially autocorrelated ecological data using integrated nested Laplace approximation
Authors: Beguin Julien , Martino Sara , Rue Håvard , Cumming Steven G.
Published: May 2012

1. Spatial analysis of ecological data is central to many interesting questions in ecology. Bayesian implementation of spatially explicit models has received increasing attention from ecologists as Monte Carlo Markov Chain (MCMC) methods have become freely accessible. MCMC simulations offer a flexible framework for modelling extensive ecological data, but they also come with a wide range of problems regarding convergence, processing time and implementation.

2. We introduce to ecologists an alternative procedure for fitting Bayesian hierarchical spatial models (BHSM) with quite general spatial covariance structures. This procedure uses integrated nested Laplace approximations (INLA) as an alternative to MCMC.

3. We show, using a case study of species distribution model with binary areal data, that implementing BHSM with INLA does not require advanced programming skills, yields accurate results compared with MCMC and is rapid (e.g. a few seconds with small to moderate data sets). BHSMs efficiently removed spatial autocorrelation in the residuals and fairly evaluated uncertainty in parameter estimates and predictions.

4. The rapidity of INLA significantly decreased the processing time and allowed both sensitivity analyses on priors and cross‐validation tests to be performed within a reasonable amount of time, which ultimately increased model transparency.
Hesperidin-mediated expression of Nrf2 and upregulation of antioxidant status in senescent rat heart
Authors: Elavarasan Jayasudha , Velusamy Prema , Ganesan Thellamudhu , Ramakrishnan Suresh Krishna , Rajasekaran Devaraja , Periandavan Kalaiselvi
Published: May 2012

Objectives

Oxidative stress is recognized as a key element responsible for the development of age-related pathologies. A declining endogenous defence system during senescence dictates the need for supplementation with exogenous antioxidants through diet. Hesperidin is a naturally occurring flavonone present in citrus fruits and has been shown to have many biological properties, including antioxidant activity. We investigated whether hesperidin supplementation could be valuable in protecting cardiac tissue of aged rats against age-related increase in oxidative stress, as well as the mechanism by which it can boost the antioxidant status of the cell.

Methods

The activity of antioxidant enzymes, mRNA expression of Nrf2, protein levels of superoxide dismutase and catalase were measured using standard protocols.

Key findings

Hesperidin treatment effectively protected aged rat heart by increasing the activity of enzymic antioxidants. Hesperidin upregulated the protein levels of nuclear factor erythroid 2-related factor 2, which is responsible for maintaining the antioxidant status of the cell.

Conclusions

Hesperidin could be useful in protecting cardiomyocytes against age-related increase in oxidative stress mediated by Nrf2 upregulation.
Berberine suppresses amyloid-beta-induced inflammatory response in microglia by inhibiting nuclear factor-kappaB and mitogen-activated protein kinase signalling pathways
Authors: Jia Liyun , Liu Jing , Song Zhen , Pan Xiaohua , Chen Liang , Cui Xing , Wang Molin
Published: May 2012

Objectives

The neuroinflammation induced by amyloid-beta peptide (Aβ) is one of the key events in Alzheimer's disease (AD) progress in which microglia are the main cells involved. Berberine, one of the major constituents of Chinese herb Rhizoma coptidis, is known for its anti-inflammatory, anti-oxidative and anti-microbial activity. In this study, we examined the effects and possible underlying mechanisms of berberine in Aβ-induced neuroinflammation using murine primary microglia cells and cultured BV2 microglia cells.

Methods

The effects of berberine on Aβ-stimulated inflammatory factor expression and secretion were examined using RT-PCR and ELISA analysis. The signal pathways involved in berberine's effects were also investigated using Western blot and immunofluorescence analysis.

Results

In primary microglial and BV2 cells, berberine treatment significantly inhibited Aβ-stimulated production of interleukin-6 and monocyte chemotactic protein-1. Berberine treatment down-regulated the expression of cyclo-oxygenase-2 and induced nitric oxide synthase in these cells. Moreover, berberine strongly inhibited the nuclear factor-kappaB (NF-κB) activation, presumably through blocking the phosphoinositide 3-kinase/protein kinase B and mitogen-activated protein kinase signalling pathways.

Conclusions

Our data indicated berberine is a potent suppressor of neuroflammation, presumably through inhibition of NF-κB activation, and suggested berberine has therapeutic potential for the treatment of neuroinflammation that is involved in neurological diseases such as AD.
Comparative study of liposomes, transfersomes, ethosomes and cubosomes for transcutaneous immunisation: characterisation and in vitro skin penetration
Authors: Rattanapak Teerawan , Young Katie , Rades Thomas , Hook Sarah
Published: May 2012

Objectives

Lipid colloidal vaccines, including liposomes, transfersomes, ethosomes and cubosomes, were formulated, characterised and investigated for their ability to enhance penetration of a peptide vaccine through stillborn piglet skin in vitro.

Methods

Liposomes and transfersomes were formulated using a film-hydration method, ethosomes using a modified reverse phase method and cubosomes using a lipid precursor method. The size, zeta potential, peptide loading and interfacial behaviour of the formulations were characterised. Skin penetration studies were performed using Franz diffusion cells with piglet skin as the membrane. The localization of peptide in the skin was examined using confocal laser scanning microscopy.

Key finding

The various formulations contained negatively charged particles of similar size (range: 134–200 nm). Addition of the saponin adjuvant Quil A to the formulations destabilised the monolayers and reduced peptide loading. Cubosomes and ethosomes showed superior skin retention compared with the other systems. Confocal laser scanning microscopy showed greater peptide penetration and accumulation in the skin treated with cubosomes and ethosomes. With the other systems peptide was only located in the vicinity of the hair follicles and within the hair shaft.

Conclusions

We conclude from the in-vitro studies that cubosomes and ethosomes are promising lipid carriers for transcutaneous immunisation.
Relationship of insulin, glucose, leptin, IL‐6 and TNF‐α in human breast milk with infant growth and body composition
Authors: Fields D. A. , Demerath E. W.
Published: May 2012

Background

Numerous appetite, growth, obesity‐related hormones and inflammatory factors are found in human breast‐milk, but there is little evidence on their relationship with infant body composition.

Objectvie

The purpose of the present cross‐sectional pilot study was to assess the cross‐sectional associations of appetite‐regulating hormones and growth factors (leptin, insulin and glucose) and inflammatory factors (interleukin 6 (IL‐6) and tumor necrosis factor alpha (TNF‐α)) in human breast‐milk with infant size, adiposity, and lean tissue at 1‐month of age in healthy term infants.

Methods

Human breast‐milk was collected from nineteen exclusively breast‐feeding mothers using one full breast expression between 8:00 and 10:00 a.m. The milk was then mixed, aliquoted, stored at −80°C and then centrifuged to remove the milk fat, prior to analyses using commercially available immunoassay kits; milk analytes were natural log transformed prior to analysis. Infant body composition was assessed using a Lunar iDXA v11‐30.062 scanner (Infant whole body analysis enCore 2007 software, GE, Fairfield, CT).

Results

Maternal pre‐pregnancy BMI was positively associated with milk leptin concentration (P = 0.0027), and so maternal‐BMI‐adjusted Spearman correlations were examined between breast‐milk analytes and infant growth and body composition variables. As previously reported, greater milk leptin was associated with lower BMIZ (BMI‐for‐age z‐score based on WHO 2006 growth charts; r = −0.54, P = 0.03). Glucose was positively associated with relative weight (r = 0.6, P = 0.01), and both fat and lean mass (0.43–0.44, P < 0.10). Higher concentrations of milk insulin were associated with lower infant weight, relative weight, and lean mass (r = −0.49–0.58, P < 0.06). Higher milk IL‐6 was associated with lower relative weight, weight gain, percent fat, and fat mass (r = −0.55–0.70, P< 0.03 for all), while higher TNF‐α was associated with lower lean mass (r = −0.58, P = 0.05), but not measures of adiposity.

Conclusions

These preliminary data suggest for the first time that in the first months of life, breast‐milk concentrations of insulin, glucose, IL‐6 and TNF‐α, in addition to leptin, may be bioactive and differentially influence the accrual of fat and lean body mass.
Groups acting simply transitively on vertex sets of hyperbolic triangular buildings
Authors: Carbone Lisa , Kangaslampi Riikka , Vdovina Alina
Published: May 2012

We construct and classify all groups given by triangular presentations associated to the smallest thick generalized quadrangle that act simply transitively on the vertices of hyperbolic triangular buildings of the smallest non-trivial thickness. Our classification yields 23 non-isomorphic torsion-free groups (which were obtained in an earlier work) and 168 non-isomorphic torsion groups acting on one of two possible buildings with the smallest thick generalized quadrangle as the link of each vertex. In analogy with the $\widetilde {A}_2$ case, we find both torsion and torsion-free groups acting on the same building.
Potential increase in biological effectiveness from field timing optimization for stereotactic body radiation therapy
Authors: Schmitt Jonathan D. , Warren Graham W. , Wang Iris Z.
Published: May 2012

Purpose:

Stereotactic body radiation therapy (SBRT) is a radiotherapy technique which uses high dose fractions with multiple coplanar and noncoplanar beams. Due to the large fractional doses, treatments are typically protracted and there are more fields than in conventional radiation treatment schemes. The effect of temporal optimization on the biological effectiveness of SBRT is not well established.

Methods:

In a cohort of actual SBRT patient treatments, the Lea–Catcheside protraction factor (G‐value) was used to determine the optimal () and the least favorable (V) field. An actual field timing delivered in the clinic was included (C) for comparison. The lethal potential lethal (LPL) model was used to quantify the difference in survival fractions. Published data from three cell lines for non‐small cell lung cancers: H460, H660, and H157 were used to acquire the parameters needed by the LPL model. The results are expressed as the ratios and , where N is the number fractions in the SBRT protocols and , V, and C are the survival fractions calculated from the corresponding temporal patterns.

Results:

The results indicate that variability in the dose rate between fields does impact the optimization results. This dependence on dose rate, however, is small compared to the impact from the variability in doses between fields. The optimized field arrangements resembled previous studies, that maximization of cell kill is achieved by orienting the fields in a shape sequence, where the fields with greatest dose are positioned in the center. Minimization of cell kill was achieved with a V‐shaped orientation. Smallest dose fields were positioned centrally, and higher dose fields were placed in the beginning and end of the fraction. The survival fraction ratios calculated using the LPL demonstrated that regardless of the cell type the shape had lower cell survival fractions compared to both the clinical example (C) and the V arrangement. For H460, with  = 0.25 h, an average ratio of , suggesting the pattern is approximately 14 times more effective than the clinical plan, after 5 fractions.

Conclusions:

Rearranging field timing for a SBRT treatment so that maximal dose is deposited in the central fields of treatment may optimize cell kill and potentially affect overall treatment outcome.
A hybrid electron and photon IMRT planning technique that lowers normal tissue integral patient dose using standard hardware
Authors: Rosca Florin
Published: May 2012

Purpose:

To present a mixed electron and photon IMRT planning technique using electron beams with an energy range of 6–22 MeV and standard hardware that minimizes integral dose to patients for targets as deep as 7.5 cm.

Methods:

Ten brain cases, two lung, a thyroid, an abdominal, and a parotid case were planned using two planning techniques: a photon‐only IMRT (IMRT) versus a mixed modality treatment (E + IMRT) that includes anenface electron beam and a photon IMRT portion that ensures a uniform target coverage. The electron beam is delivered using a regular cutout placed in an electron cone. The electron energy was chosen to provide a good trade‐off between minimizing integral dose and generating a uniform, deliverable plan. The authors choose electron energies that cover the deepest part of PTV with the 65%–70% isodose line. The normal tissue integral dose, the dose for ring structures around the PTV, and the volumes of the 75%, 50%, and 25% isosurfaces were used to compare the dose distributions generated by the two planning techniques.

Results:

The normal tissue integral dose was lowered by about 20% by the E + IMRT plans compared to the photon‐only IMRT ones for most studied cases. With the exception of lungs, the dose reduction associated to the E + IMRT plans was more pronounced further away from the target. The average dose ratio delivered to the 0–2 cm and the 2–4 cm ring structures for brain patients for the two planning techniques were 89.6% and 70.8%, respectively. The enhanced dose sparing away from the target for the brain patients can also be observed in the ratio of the 75%, 50%, and 25% isodose line volumes for the two techniques, which decreases from 85.5% to 72.6% and further to 65.1%, respectively. For lungs, the lateral electron beams used in the E + IMRT plans were perpendicular to the mostly anterior/posterior photon beams, generating much more conformal plans.

Conclusions:

The authors proved that even using the existing electron delivery hardware, a mixed electron/photon planning technique (E + IMRT) can decrease the normal tissue integral dose compared to a photon‐only IMRT plan. Different planning approaches can be enabled by the use of an electron beam directed toward organs at risk distal to the target, which are still spared due the rapid dose fall‐off of the electron beam. Examples of such cases are the lateral electron beams in the thoracic region that do not irradiate the heart and contralateral lung, electron beams pointed toward kidneys in the abdominal region, or beams treating brain lesions pointed toward the brainstem or optical apparatus. For brain, electron vertex beams can also be used without irradiating the whole body. Since radiation retreatments become more and more common, minimizing the normal tissue integral dose and the dose delivered to tissues surrounding the target, as enabled by E + IMRT type techniques, should receive more attention.
On proton CT reconstruction using MVCT‐converted virtual proton projections
Authors: Wang Dongxu , Mackie T. Rockwell , Tomé Wolfgang A.
Published: May 2012

Purpose:

To describe a novel methodology of converting megavoltage x‐ray projections into virtual proton projections that are otherwise missing due to the proton range limit. These converted virtual proton projections can be used in the reconstruction of proton computed tomography (pCT).

Methods:

Relations exist between proton projections and multispectral megavoltage x‐ray projections for human tissue. Based on these relations, these tissues can be categorized into: (a) adipose tissue; (b) nonadipose soft tissues; and (c) bone. These three tissue categories can be visibly identified on a regular megavoltage x‐ray computed tomography (MVCT) image. With an MVCT image and its projection data available, the x‐ray projections through heterogeneous anatomy can be converted to the corresponding proton projections using predetermined calibration curves for individual materials, aided by a coarse segmentation on the x‐ray CT image. To show the feasibility of this approach, mathematical simulations were carried out. The converted proton projections, plotted on a proton sinogram, were compared to the simulated ground truth. Proton stopping power images were reconstructed using either the virtual proton projections only or a blend of physically available proton projections and virtual proton projections that make up for those missing due to the range limit. These images were compared to a reference image reconstructed from theoretically calculated proton projections.

Results:

The converted virtual projections had an uncertainty of ±0.8% compared to the calculated ground truth. Proton stopping power images reconstructed using a blend of converted virtual projections (48%) and physically available projections (52%) had an uncertainty of ±0.86% compared with that reconstructed from theoretically calculated projections. Reconstruction solely from converted virtual proton projections had an uncertainty of ±1.1% compared with that reconstructed from theoretical projections. If these images are used for treatment planning, the average proton range uncertainty is estimated to be less than 1.5% for an imaging dose in the milligray range.

Conclusions:

The proposed method can be used to convert x‐ray projections into virtual proton projections. The converted proton projections can be blended with existing proton projections or can be used solely for pCT reconstruction, addressing the range limit problem of pCT using current therapeutic proton machines.
Investigations of cabin design in UV phototherapy
Authors: Grimes David Robert , Martin Colin J , Phanco Graeme
Published: May 2012

Purpose:

UVR phototherapy cabins exist in a huge variety of configurations and geometries. An accurate dose model has been developed which can be used to examine the question of cabin design to investigate factors influencing dose on a patient.

Methods:

This work extends the existing dose model to entire cabins and investigates how cabin and reflector geometry influence resultant dose.

Results:

The model predictions are in line with what is measured. It is found that the length and angle of the reflectors have a large influence on received dose.

Conclusions:

The influence of cabin geometry is important in estimating patient dose, and the findings of this work are applicable to future cabin designs.
Establishing a standard calibration methodology for MOSFET detectors in computed tomography dosimetry
Authors: Brady S. L. , Kaufman R. A.
Published: May 2012

Purpose:

The use of metal‐oxide‐semiconductor field‐effect transistor (MOSFET) detectors for patient dosimetry has increased by ∼25% since 2005. Despite this increase, no standard calibration methodology has been identified nor calibration uncertainty quantified for the use of MOSFET dosimetry in CT. This work compares three MOSFET calibration methodologies proposed in the literature, and additionally investigates questions relating to optimal time for signal equilibration and exposure levels for maximum calibration precision.

Methods:

The calibration methodologies tested were (1) free in‐air (FIA) with radiographic x‐ray tube, (2) FIA with stationary CT x‐ray tube, and (3) within scatter phantom with rotational CT x‐ray tube. Each calibration was performed at absorbed dose levels of 10, 23, and 35 mGy. Times of 0 min or 5 min were investigated for signal equilibration before or after signal read out.

Results:

Calibration precision was measured to be better than 5%–7%, 3%–5%, and 2%–4% for the 10, 23, and 35 mGy respective dose levels, and independent of calibration methodology. No correlation was demonstrated for precision and signal equilibration time when allowing 5 min before or after signal read out. Differences in average calibration coefficients were demonstrated between the FIA with CT calibration methodology 26.7 ± 1.1 mV cGy−1 versus the CT scatter phantom 29.2 ± 1.0 mV cGy−1 and FIA with x‐ray 29.9 ± 1.1 mV cGy−1 methodologies. A decrease in MOSFET sensitivity was seen at an average change in read out voltage of ∼3000 mV.

Conclusions:

The best measured calibration precision was obtained by exposing the MOSFET detectors to 23 mGy. No signal equilibration time is necessary to improve calibration precision. A significant difference between calibration outcomes was demonstrated for FIA with CT compared to the other two methodologies. If the FIA with a CT calibration methodology was used to create calibration coefficients for the eventual use for phantom dosimetry, a measurement error ∼12% will be reflected in the dosimetry results. The calibration process must emulate the eventual CT dosimetry process by matching or excluding scatter when calibrating the MOSFETs. Finally, the authors recommend that the MOSFETs are energy calibrated approximately every 2500–3000 mV.
ELSI 2.0 for Genomics and Society
Authors: Kaye Jane , Meslin Eric M. , Knoppers Bartha M. , Juengst Eric T. , Deschênes Mylène , Cambon-Thomsen Anne , Chalmers Donald , De Vries Jantina , Edwards Kelly , Hoppe Nils , Kent Alastair , Adebamowo Clement , Marshall Patricia , Kato Kazuto
Published: May 2012

We need an international infrastructure for the ethical, legal, and social implications of genomic research.
Color and Albedo Heterogeneity of Vesta from Dawn
Authors: Reddy Vishnu , Nathues Andreas , Le Corre Lucille , Sierks Holger , Li Jian-Yang , Gaskell Robert , McCoy Timothy , Beck Andrew W. , Schröder Stefan E. , Pieters Carle M. , Becker Kris J. , Buratti Bonnie J. , Denevi Brett , Blewett David T. , Christensen Ulrich , Gaffey Michael J. , Gutierrez-Marques Pablo , Hicks Michael , Keller Horst Uwe , Maue Thorsten , Mottola Stefano , McFadden Lucy A. , McSween Harry Y. , Mittlefehldt David , O’Brien David P. , Raymond Carol , Russell Christopher
Published: May 2012

A New Dawn

Since 17 July 2011, NASA's spacecraft Dawn has been orbiting the asteroid Vesta—the second most massive and the third largest asteroid in the solar system (see the cover).

Russell
et al.

(p.
684
) use Dawn's observations to confirm that Vesta is a small differentiated planetary body with an inner core, and represents a surviving proto-planet from the earliest epoch of solar system formation; Vesta is also confirmed as the source of the howardite-eucrite-diogenite (HED) meteorites.

Jaumann
et al.

(p.
687
) report on the asteroid's overall geometry and topography, based on global surface mapping. Vesta's surface is dominated by numerous impact craters and large troughs around the equatorial region.

Marchi
et al.

(p.
690
) report on Vesta's complex cratering history and constrain the age of some of its major regions based on crater counts.

Schenk
et al.

(p.
694
) describe two giant impact basins located at the asteroid's south pole. Both basins are young and excavated enough amounts of material to form the Vestoids—a group of asteroids with a composition similar to that of Vesta—and HED meteorites.

De Sanctis
et al.

(p.
697
) present the mineralogical characterization of Vesta, based on data obtained by Dawn's visual and infrared spectrometer, revealing that this asteroid underwent a complex magmatic evolution that led to a differentiated crust and mantle. The global color variations detailed by

Reddy
et al.

(p.
700
) are unlike those of any other asteroid observed so far and are also indicative of a preserved, differentiated proto-planet.
Vesta’s Shape and Morphology
Authors: Jaumann R. , Williams D. A. , Buczkowski D. L. , Yingst R. A. , Preusker F. , Hiesinger H. , Schmedemann N. , Kneissl T. , Vincent J. B. , Blewett D. T. , Buratti B. J. , Carsenty U. , Denevi B. W. , De Sanctis M. C. , Garry W. B. , Keller H. U. , Kersten E. , Krohn K. , Li J.-Y. , Marchi S. , Matz K. D. , McCord T. B. , McSween H. Y. , Mest S. C. , Mittlefehldt D. W. , Mottola S. , Nathues A. , Neukum G. , O’Brien D. P. , Pieters C. M. , Prettyman T. H. , Raymond C. A. , Roatsch T. , Russell C. T. , Schenk P. , Schmidt B. E. , Scholten F. , Stephan K. , Sykes M. V. , Tricarico P. , Wagner R. , Zuber M. T. , Sierks H.
Published: May 2012

A New Dawn

Since 17 July 2011, NASA's spacecraft Dawn has been orbiting the asteroid Vesta—the second most massive and the third largest asteroid in the solar system (see the cover).

Russell
et al.

(p.
684
) use Dawn's observations to confirm that Vesta is a small differentiated planetary body with an inner core, and represents a surviving proto-planet from the earliest epoch of solar system formation; Vesta is also confirmed as the source of the howardite-eucrite-diogenite (HED) meteorites.

Jaumann
et al.

(p.
687
) report on the asteroid's overall geometry and topography, based on global surface mapping. Vesta's surface is dominated by numerous impact craters and large troughs around the equatorial region.

Marchi
et al.

(p.
690
) report on Vesta's complex cratering history and constrain the age of some of its major regions based on crater counts.

Schenk
et al.

(p.
694
) describe two giant impact basins located at the asteroid's south pole. Both basins are young and excavated enough amounts of material to form the Vestoids—a group of asteroids with a composition similar to that of Vesta—and HED meteorites.

De Sanctis
et al.

(p.
697
) present the mineralogical characterization of Vesta, based on data obtained by Dawn's visual and infrared spectrometer, revealing that this asteroid underwent a complex magmatic evolution that led to a differentiated crust and mantle. The global color variations detailed by

Reddy
et al.

(p.
700
) are unlike those of any other asteroid observed so far and are also indicative of a preserved, differentiated proto-planet.
Meiosis-Specific Noncoding RNA Mediates Robust Pairing of Homologous Chromosomes in Meiosis
Authors: Ding Da-Qiao , Okamasa Kasumi , Yamane Miho , Tsutsumi Chihiro , Haraguchi Tokuko , Yamamoto Masayuki , Hiraoka Yasushi
Published: May 2012

Find Your Partner

Gametes generally have haploid genomes, so that when they fuse during fertilization, they reconstitute a diploid organism. Meiosis is required to make haploid gametes, which involves a reduction division where two homologous chromosomes first pair and are then segregated away from each other. Working in the fission yeast
Schizosaccharomyces pombe
,

Ding
et al.

(p.
732
; see the Perspective by

Dernburg

) explored how homologous chromosomes recognized each other and found that a non-coding RNA locus,
sme2
, helps to drive the pairing of homologous chromosomes.
Understanding Earthquakes
Authors: Segall Paul
Published: May 2012

Sophisticated numerical models can reproduce a wide range of seismic activity at the Parkfield segment of the San Andreas Fault.
PARP-1 Activation—Bringing the Pieces Together
Authors: Gagné Jean-Philippe , Rouleau Michèle , Poirier Guy G.
Published: May 2012

A model structure sheds light on how the PARP-1 protein is activated in DNA repair.
Tackling Human Fungal Infections
Authors: Brown Gordon D. , Denning David W. , Levitz Stuart M.
Published: May 2012

Fungi infect billions of people every year, yet their contribution to the global burden of disease is largely unrecognized. Most are “relatively” minor infections, but millions contract diseases that kill at least as many people as tuberculosis or malaria. Although true mortality rates are unknown because of a lack of good epidemiological data, the incidence of invasive fungal infections is rising as a result of modern medical interventions and immunosuppressive diseases, such as AIDS. Despite the high mortality rates of invasive fungal infections, they remain understudied and underdiagnosed as compared with other infectious diseases. What can be done to remedy this unfortunate situation?
FGF21 Takes a Fat Bite
Authors: Cantó Carles , Auwerx Johan
Published: May 2012

A growth factor's varied effects on adipose tissue and thermogenesis may be attributable to its local and systemic actions.
RNA Plays Meiotic Matchmaker
Authors: Dernburg Abby F.
Published: May 2012

RNA plays a role in homologous chromosome pairing during meiosis.
The Geologically Recent Giant Impact Basins at Vesta’s South Pole
Authors: Schenk Paul , O’Brien David P. , Marchi Simone , Gaskell Robert , Preusker Frank , Roatsch Thomas , Jaumann Ralf , Buczkowski Debra , McCord Thomas , McSween Harry Y. , Williams David , Yingst Aileen , Raymond Carol , Russell Chris
Published: May 2012

A New Dawn

Since 17 July 2011, NASA's spacecraft Dawn has been orbiting the asteroid Vesta—the second most massive and the third largest asteroid in the solar system (see the cover).

Russell
et al.

(p.
684
) use Dawn's observations to confirm that Vesta is a small differentiated planetary body with an inner core, and represents a surviving proto-planet from the earliest epoch of solar system formation; Vesta is also confirmed as the source of the howardite-eucrite-diogenite (HED) meteorites.

Jaumann
et al.

(p.
687
) report on the asteroid's overall geometry and topography, based on global surface mapping. Vesta's surface is dominated by numerous impact craters and large troughs around the equatorial region.

Marchi
et al.

(p.
690
) report on Vesta's complex cratering history and constrain the age of some of its major regions based on crater counts.

Schenk
et al.

(p.
694
) describe two giant impact basins located at the asteroid's south pole. Both basins are young and excavated enough amounts of material to form the Vestoids—a group of asteroids with a composition similar to that of Vesta—and HED meteorites.

De Sanctis
et al.

(p.
697
) present the mineralogical characterization of Vesta, based on data obtained by Dawn's visual and infrared spectrometer, revealing that this asteroid underwent a complex magmatic evolution that led to a differentiated crust and mantle. The global color variations detailed by

Reddy
et al.

(p.
700
) are unlike those of any other asteroid observed so far and are also indicative of a preserved, differentiated proto-planet.
Death of California Researcher Spurs Investigation
Authors: Miller Greg
Published: May 2012

Local and federal health agencies are investigating the death of Richard Din, a 25-year-old research associate at the Veterans Affairs Medical Center in San Francisco, California.
Venus's Rare Sun Crossing May Aid Search for Exoplanets
Authors: Cowen Ron
Published: May 2012

Early next month, skywatchers will get their second—and final—chance this century to observe a rare mini-eclipse in which Venus crosses in front of the sun.
Researchers Set Course To Blockade Ballast Invaders
Authors: Strain Daniel
Published: May 2012

As U.S. regulations loom, scientists are working to test new devices that can remove potentially invasive organisms from ships' ballast water.
With Novel Paint, Chemist Aims To Vanquish the
Vinchuca
Authors: Friedman-Rudovsky Jean
Published: May 2012

Spanish chemist Pilar Mateo invented a clever way to package insect-control agents in paint; after a decade of trying, she's persuaded Bolivia to give it a test.
LIFE SCIENCE TECHNOLOGIES: Spot-On Protein Microarrays: An Old Proteomics Tool
Authors: Perkel Jeffrey M.
Published: May 2012

When it comes to 'omics-inspired bioscience tools, next-gen DNA sequencing is the undisputed king. The previous champ was the DNA microarray, with the protein array its logical successor. Yet while DNA arrays achieved their potential, protein arrays never really took off, owing largely to the fact that, while every DNA oligo behaves more or less identically, the same cannot be said of proteins. They're also harder to synthesize, purify, and stabilize. Still, to paraphrase Mark Twain, the rumor of protein array's death has been greatly exaggerated. Today, new array formats and strategies have made the protein microarray a viable and growing tool for biomarker discovery, interactome research, functional genomics, and more.
Molecular Detection of Plasmodium knowlesi in a Dutch Traveler by Real-Time PCR
Authors: Link Lonneke , Bart Aldert , Verhaar Nienke , van Gool Tom , Pronk Marjolijn , Scharnhorst Volkher
Published: May 2012

Plasmodium knowlesi
infection with low parasitemia presents a diagnostic challenge, as rapid diagnostic tests are often negative and identification to the species level by microscopy is difficult.
P. knowlesi
malaria in a traveler is described, and real-time PCR is demonstrated to support fast and reliable diagnosis and identification to the species level.
Crystal Structure of the Superfamily 1 Helicase from Tomato Mosaic Virus
Authors: Nishikiori Masaki , Sugiyama Shigeru , Xiang Hongyu , Niiyama Mayumi , Ishibashi Kazuhiro , Inoue Tsuyoshi , Ishikawa Masayuki , Matsumura Hiroyoshi , Katoh Etsuko
Published: May 2012

The genomes of the
Tomato mosaic virus
and many other plant and animal positive-strand RNA viruses of agronomic and medical importance encode superfamily 1 helicases. Although helicases play important roles in viral replication, the crystal structures of viral superfamily 1 helicases have not been determined. Here, we report the crystal structure of a fragment (S666 to Q1116) of the replication protein from
Tomato mosaic virus
. The structure reveals a novel N-terminal domain tightly associated with a helicase core. The helicase core contains two RecA-like α/β domains without any of the accessory domain insertions that are found in other superfamily 1 helicases. The N-terminal domain contains a flexible loop, a long α-helix, and an antiparallel six-stranded β-sheet. On the basis of the structure, we constructed deletion mutants of the S666-to-Q1116 fragment and performed split-ubiquitin-based interaction assays in
Saccharomyces cerevisiae
with TOM1 and ARL8, host proteins that are essential for tomato mosaic virus RNA replication. The results suggested that both TOM1 and ARL8 interact with the long α-helix in the N-terminal domain and that TOM1 also interacts with the helicase core. Prediction of secondary structures in other viral superfamily 1 helicases and comparison of those structures with the S666-to-Q1116 structure suggested that these helicases have a similar fold. Our results provide a structural basis of viral superfamily 1 helicases.
West Nile Virus T-Cell Ligand Sequences Shared with Other Flaviviruses: a Multitude of Variant Sequences as Potential Altered Peptide Ligands
Authors: Jung Keun-Ok , Khan Asif M. , Tan Benjamin Yong Liang , Hu Yongli , Simon Gregory G. , Nascimento Eduardo J. M. , Lemonnier Francois , Brusic Vladimir , Miotto Olivo , Tan Tin Wee , Marques Ernesto T. A. , Dhalia Rafael , Salmon Jerome , August J. Thomas
Published: May 2012

Phylogenetic relatedness and cocirculation of several major human pathogen flaviviruses are recognized as a possible cause of deleterious immune responses to mixed infection or immunization and call for a greater understanding of the inter-Flavivirusprotein homologies. This study focused on the identification of human leukocyte antigen (HLA)-restrictedWest Nile virus(WNV) T-cell ligands and characterization of their distribution in reported sequence data of WNV and other flaviviruses. H-2-deficient mice transgenic for either A2, A24, B7, DR2, DR3, or DR4 HLA alleles were immunized with overlapping peptides of the WNV proteome, and peptide-specific T-cell activation was measured by gamma interferon (IFN-γ) enzyme-linked immunosorbent spot (ELISpot) assays. Approximately 30% (137) of the WNV proteome peptides were identified as HLA-restricted T-cell ligands. The majority of these ligands were conserved in ∼≥88% of analyzed WNV sequences. Notably, only 51 were WNV specific, and the remaining 86, chiefly of E, NS3, and NS5, shared an identity of nine or more consecutive amino acids with sequences of 64 other flaviviruses, including several major human pathogens. Many of the shared ligands had an incidence of >50% in the analyzed sequences of one or more of six major flaviviruses. The multitude of WNV sequences shared with other flaviviruses as interspecies variants highlights the possible hazard of defective T-cell activation by altered peptide ligands in the event of dual exposure to WNV and other flaviviruses, by either infection or immunization. The data suggest the possible preferred use of sequences that are pathogen specific with minimum interspecies sequence homology for the design ofFlavivirusvaccines.
Mosquito Bite Delivery of Dengue Virus Enhances Immunogenicity and Pathogenesis in Humanized Mice
Authors: Cox Jonathan , Mota Javier , Sukupolvi-Petty Soila , Diamond Michael S. , Rico-Hesse Rebeca
Published: May 2012

Dengue viruses (DENV) are transmitted to humans by the bite of
Aedes aegypti
or
Aedes albopictus
mosquitoes, with millions of infections annually in over 100 countries. The diseases they produce, which occur exclusively in humans, are dengue fever (DF) and dengue hemorrhagic fever (DHF). We previously developed a humanized mouse model of DF in which mice transplanted with human hematopoietic stem cells produced signs of DENV disease after injection with low-passage, wild-type isolates. Using these mice, but now allowing infected
A. aegypti
to transmit dengue virus during feeding, we observed signs of more severe disease (higher and more sustained viremia, erythema, and thrombocytopenia). Infected mice mounted innate (gamma interferon [IFN-γ] and soluble interleukin 2 receptor alpha [sIL-2Rα]) and adaptive (anti-DENV antibodies) immune responses that failed to clear viremia until day 56, while a mosquito bite alone induced strong immunomodulators (tumor necrosis factor alpha [TNF-α], IL-4, and IL-10) and thrombocytopenia. This is the first animal model that allows an evaluation of human immunity to DENV infection after mosquito inoculation.
Specific CD8
+
T Cell Responses Correlate with Control of Simian Immunodeficiency Virus Replication in Mauritian Cynomolgus Macaques
Authors: Budde Melisa L. , Greene Justin M. , Chin Emily N. , Ericsen Adam J. , Scarlotta Matthew , Cain Brian T. , Pham Ngoc H. , Becker Ericka A. , Harris Max , Weinfurter Jason T. , O'Connor Shelby L. , Piatak Michael , Lifson Jeffrey D. , Gostick Emma , Price David A. , Friedrich Thomas C. , O'Connor David H.
Published: May 2012

Specific major histocompatibility complex (MHC) class I alleles are associated with an increased frequency of spontaneous control of human and simian immunodeficiency viruses (HIV and SIV). The mechanism of control is thought to involve MHC class I-restricted CD8
+
T cells, but it is not clear whether particular CD8
+
T cell responses or a broad repertoire of epitope-specific CD8
+
T cell populations (termed T cell breadth) are principally responsible for mediating immunologic control. To test the hypothesis that heterozygous macaques control SIV replication as a function of superior T cell breadth, we infected MHC-homozygous and MHC-heterozygous cynomolgus macaques with the pathogenic virus SIVmac239. As measured by a gamma interferon enzyme-linked immunosorbent spot assay (IFN-γ ELISPOT) using blood, T cell breadth did not differ significantly between homozygotes and heterozygotes. Surprisingly, macaques that controlled SIV replication, regardless of their MHC zygosity, shared durable T cell responses against similar regions of Nef. While the limited genetic variability in these animals prevents us from making generalizations about the importance of Nef-specific T cell responses in controlling HIV, these results suggest that the T cell-mediated control of virus replication that we observed is more likely the consequence of targeting specificity rather than T cell breadth.
The Dominant-Negative Inhibition of Double-Stranded RNA-Dependent Protein Kinase PKR Increases the Efficacy of Rift Valley Fever Virus MP-12 Vaccine
Authors: Lihoradova Olga , Kalveram Birte , Indran Sabarish V. , Lokugamage Nandadeva , Juelich Terry L. , Hill Terence E. , Tseng Chien-Te K. , Gong Bin , Fukushi Shuetsu , Morikawa Shigeru , Freiberg Alexander N. , Ikegami Tetsuro
Published: May 2012

Rift Valley fever virus (RVFV), belonging to the genusPhlebovirus, familyBunyaviridae, is endemic to sub-Saharan Africa and causes a high rate of abortion in ruminants and hemorrhagic fever, encephalitis, or blindness in humans. MP-12 is the only RVFV strain excluded from the select-agent rule and handled at a biosafety level 2 (BSL2) laboratory. MP-12 encodes a functional major virulence factor, the NSs protein, which contributes to its residual virulence in pregnant ewes. We found that 100% of mice subcutaneously vaccinated with recombinant MP-12 (rMP12)-murine PKRN167 (mPKRN167), which encodes a dominant-negative form of mouse double-stranded RNA (dsRNA)-dependent protein kinase (PKR) in place of NSs, were protected from wild-type (wt) RVFV challenge, while 72% of mice vaccinated with MP-12 were protected after challenge. rMP12-mPKRN167 induced alpha interferon (IFN-α) in sera, accumulated RVFV antigens in dendritic cells at the local draining lymph nodes, and developed high levels of neutralizing antibodies, while parental MP-12 induced neither IFN-α nor viral-antigen accumulation at the draining lymph node yet induced a high level of neutralizing antibodies. The present study suggests that the expression of a dominant-negative PKR increases the immunogenicity and efficacy of live-attenuated RVFV vaccine, which will lead to rational design of safe and highly immunogenic RVFV vaccines for livestock and humans.
Refined Identification of Neutralization-Resistant HIV-1 CRF02_AG Viruses
Authors: Jacob Rajesh Abraham , Abrahams Fatima , Tongo Marcel , Schomaker Michael , Roux Paul , Mpoudi Ngole Eitel , Burgers Wendy A. , Dorfman Jeffrey R.
Published: May 2012

We studied neutralization of CRF02_AG HIV-1-infected plasma samples. In contrast to previous reports, these samples neutralized CRF02_AG viruses better than other viruses. This included six of eight CRF02_AG viruses previously designated resistant (tier 2/3 or 3). Only viruses 253-11 and 278-50 remained highly resistant, but they were sensitive to membrane-proximal external region (MPER)-specific monoclonal antibodies, suggesting neutralization targets for even these viruses. We propose using high-neutralizing-within-subtype samples for evaluation of neutralization resistance of viruses.
Update on feline infectious peritonitis
Authors: German Allison
Published: May 2012

Feline infectious peritonitis (FIP) remains one of the most challenging diseases to manage in veterinary practice. It is difficult to diagnose and almost impossible to treat, and can be a source of distress and financial burden for both cat owners and breeders. This article provides an update on recent developments in the pathogenesis and diagnosis of the condition, and discusses treatment options for appropriate cases.