bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of the Inward Remodeling Process in Resistance Vessels: Is the Actin Cytoskeleton Involved?
Authors: Castorena‐Gonzalez Jorge A. , Staiculescu Marius C. , Foote Christopher , Martinez‐Lemus Luis A.
Published: November 2013

The resistance arteries and arterioles are the vascular components of the circulatory system where the greatest drop in blood pressure takes place. Consequently, these vessels play a preponderant role in the regulation of blood flow and the modulation of blood pressure. For this reason, the inward remodeling process of the resistance vasculature, as it occurs in hypertension, has profound consequences on the incidence of life‐threatening cardiovascular events. In this manuscript, we review some of the most prominent characteristics of inwardly remodeled resistance arteries including their changes in vascular passive diameter, wall thickness, and elastic properties. Then, we explore the known contribution of the different components of the vascular wall to the characteristics of inwardly remodeled vessels, and pay particular attention to the role the vascular smooth muscle actin cytoskeleton may play on the initial stages of the remodeling process. We end by proposing potential ways by which many of the factors and mechanisms known to participate in the inward remodeling process may be associated with cytoskeletal modifications and participate in reducing the passive diameter of resistance vessels.
Priming of protein expression in the defence response of Zantedeschia aethiopica to Pectobacterium carotovorum
Authors: Luzzatto‐Knaan Tal , Kerem Zohar , Doron‐Faigenboim Adi , Yedidia Iris
Published: November 2013

The defence response of Zantedeschia aethiopica, a natural rhizomatous host of the soft rot bacterium Pectobacterium carotovorum, was studied following the activation of common induced resistance pathways—systemic acquired resistance and induced systemic resistance. Proteomic tools were used, together with in vitro quantification and in situ localization of selected oxidizing enzymes. In total, 527 proteins were analysed by label‐free mass spectrometry (MS) and annotated against the National Center for Biotechnology Information (NCBI) nonredundant (nr) protein database of rice (Oryza sativa). Of these, the fore most differentially expressed group comprised 215 proteins that were primed following application of methyl jasmonate (MJ) and subsequent infection with the pathogen. Sixty‐five proteins were down‐regulated following MJ treatments. The application of benzothiadiazole (BTH) increased the expression of 23 proteins; however, subsequent infection with the pathogen repressed their expression and did not induce priming. The sorting of primed proteins by Gene Ontology protein function category revealed that the primed proteins included nucleic acid‐binding proteins, cofactor‐binding proteins, ion‐binding proteins, transferases, hydrolases and oxidoreductases. In line with the highlighted involvement of oxidoreductases in the defence response, we determined their activities, priming pattern and localization in planta. Increased activities were confined to the area surrounding the pathogen penetration site, associating these enzymes with the induced systemic resistance afforded by the jasmonic acid signalling pathway. The results presented here demonstrate the concerted priming of protein expression following MJ treatment, making it a prominent part of the defence response of Z. aethiopica to P. carotovorum.
Molecular characterization and functional analyses of ZtWor1, a transcriptional regulator of the fungal wheat pathogen Zymoseptoria tritici
Authors: Mirzadi Gohari Amir , Mehrabi Rahim , Robert Olivier , Ince Ikbal Agah , Boeren Sjef , Schuster Martin , Steinberg Gero , de Wit Pierre J. G. M. , Kema Gert H. J.
Published: November 2013

Zymoseptoria tritici causes the major fungal wheat disease septoria tritici blotch, and is increasingly being used as a model for transmission and population genetics, as well as host–pathogen interactions. Here, we study the biological function of ZtWor1, the orthologue of Wor1 in the fungal human pathogen Candida albicans, as a representative of a superfamily of regulatory proteins involved in dimorphic switching. In Z. tritici, this gene is pivotal for pathogenesis, as ZtWor1 mutants were nonpathogenic and complementation restored the wild‐type phenotypes. In planta expression analyses showed that ZtWor1 is up‐regulated during the initiation of colonization and fructification, and regulates candidate effector genes, including one that was discovered after comparative proteome analysis of the Z. tritici wild‐type strain and the ZtWor1 mutant, which was particularly expressed in planta. Cell fusion and anastomosis occur frequently in ZtWor1 mutants, reminiscent of mutants of MgGpb1, the β‐subunit of the heterotrimeric G protein. Comparative expression of ZtWor1 in knock‐out strains of MgGpb1 and MgTpk2, the catalytic subunit of protein kinase A, suggests that ZtWor1 is downstream of the cyclic adenosine monophosphate (cAMP) pathway that is crucial for pathogenesis in many fungal plant pathogens.
Meditation research, past, present, and future: perspectives from the Nalanda contemplative science tradition
Authors: Loizzo Joseph
Published: November 2013

This article offers an overview of meditation research: its history, recent developments, and future directions. As the number and scope of studies grow, the field has converged with cognitive and affective neuroscience, and spawned many clinical applications. Recent work has shed light on the mechanisms and effects of diverse practices, and is entering a new phase where consensus and coherent paradigms are within reach. This article suggests an unusual path for future advancement: complementing conventional research with rigorous dialogue with the contemplative traditions that train expert meditators and best know the techniques. It explores the Nalanda tradition developed in India and preserved in Tibet, because its cumulative approach to contemplative methods produced a comprehensive framework that may help interpret data and guide research, and because its naturalistic theories and empirical methods may help bridge the gulf between science and other contemplative traditions. Examining recent findings and models in light of this framework, the article introduces the Indic map of the central nervous system and presents three testable predictions based on it. Finally, it reviews two studies that suggest that the multimodal Nalanda approach to contemplative learning is as well received as more familiar approaches, while showing promise of being more effective.
Meditative analgesia: the current state of the field
Authors: Grant Joshua A.
Published: November 2013

Since the first demonstrations that mindfulness‐based therapies could have a positive influence on chronic pain patients, numerous studies have been conducted with healthy individuals in an attempt to understand meditative analgesia. This review focuses explicitly on experimental pain studies of meditation and attempts to draw preliminary conclusions based on the work completed in this new field over the past 6 years. Dividing meditative practices into the broad categories of focused attention (FA) and open monitoring (OM) techniques allowed several patterns to emerge. The majority of evidence for FA practices suggests they are not particularly effective in reducing pain. OM, on the other hand, seems to influence both sensory and affective pain ratings depending on the tradition or on whether the practitioners were meditating. The neural pattern underlying pain modulation during OM suggests meditators actively focus on the noxious stimulation while inhibiting other mental processes, consistent with descriptions of mindfulness. A preliminary model is presented for explaining the influence of mindfulness practice on pain. Finally, the potential analgesic effect of the currently unexplored technique of compassion meditation is discussed.
Phytochelatin–metal(loid) transport into vacuoles shows different substrate preferences in barley and Arabidopsis
Authors: SONG WON‐YONG , MENDOZA‐CÓZATL DAVID G. , LEE YOUNGSOOK , SCHROEDER JULIAN I. , AHN SANG‐NAG , LEE HYUN‐SOOK , WICKER THOMAS , MARTINOIA ENRICO
Published: November 2013

Cadmium (Cd) and arsenic (As) are toxic to all living organisms, including plants and humans. In plants, Cd and As are detoxified by phytochelatins (PCs) and metal(loid)‐chelating peptides and by sequestering PC–metal(loid) complexes in vacuoles. Consistent differences have been observed between As and Cd detoxification. Whereas chelation of Cd by PCs is largely sufficient to detoxify Cd, As–PC complexes must be sequestered into vacuoles to be fully detoxified. It is not clear whether this difference in detoxification pathways is ubiquitous among plants or varies across species. Here, we have conducted a PC transport study using vacuoles isolated from Arabidopsis and barley. Arabidopsis vacuoles accumulated low levels of PC2–Cd, and vesicles from yeast cells expressing either AtABCC1 or AtABCC2 exhibited negligible PC2–Cd transport activity compared with PC2–As. In contrast, barley vacuoles readily accumulated comparable levels of PC2–Cd and PC2–As. PC transport in barley vacuoles was inhibited by vanadate, but not by ammonium, suggesting the involvement of ABC‐type transporters. Interestingly, barley vacuoles exhibited enhanced PC2 transport activity when essential metal ions, such as Zn(II), Cu(II) and Mn(II), were added to the transport assay, suggesting that PCs might contribute to the homeostasis of essential metals and detoxification of non‐essential toxic metal(loid)s.
Functional characterization of Arabidopsis HsfA6a as a heat‐shock transcription factor under high salinity and dehydration conditions
Authors: HWANG SUNG MIN , KIM DAE WON , WOO MIN SEOK , JEONG HYEONG SEOP , SON YOUNG SIM , AKHTER SALINA , CHOI GYUNG JA , BAHK JEONG DONG
Published: November 2013

Although heat‐shock transcription factors are well characterized in the heat stress‐related pathway, they are poorly understood in other stress responses. Here, we functionally characterized AtHsfA6a in the presence of exogenous abscisic acid (ABA) and under high salinity and dehydration conditions. AtHsfA6a expression under normal conditions is very low, but was highly induced by exogenous ABA, NaCl and drought. Unexpectedly, the levels of AtHsfA6a transcript were not significantly altered under heat and cold stresses. Electrophoretic mobility shift assays and transient transactivation assays indicated that AtHsfA6a is transcriptionally regulated by ABA‐responsive element binding factor/ABA‐responsive element binding protein, which are key regulators of the ABA signalling pathway. Additionally, fractionation and protoplast transient assays showed that AtHsfA6a was in cytoplasm and nucleus simultaneously; however, under conditions of high salinity the majority of AtHsfA6A was in the nucleus. Furthermore, at both seed germination and seedlings stage, plants overexpressing AtHsfA6a were hypersensitive to ABA and exhibited enhanced tolerance against salt and drought stresses. Finally, the microarray and qRT‐PCR analyses revealed that many stress‐responsive genes were up‐regulated in the plants overexpressing AtHsfA6a. Taken together, the data strongly suggest that AtHsfA6a acts as a transcriptional activator of stress‐responsive genes via the ABA‐dependent signalling pathway.
Tetraspanin 3c requirement for pigment cell interactions and boundary formation in zebrafish adult pigment stripes
Authors: Inoue Shinya , Kondo Shigeru , Parichy David M. , Watanabe Masakatsu
Published: November 2013

Skin pigment pattern formation in zebrafish requires pigment‐cell autonomous interactions between melanophores and xanthophores, yet the molecular bases for these interactions remain largely unknown. Here, we examined the dali mutant that exhibits stripes in which melanophores are intermingled abnormally with xanthophores. By in vitro cell culture, we found that melanophores of dali mutants have a defect in motility and that interactions between melanophores and xanthophores are defective as well. Positional cloning and rescue identified dali as tetraspanin 3c (tspan3c), encoding a transmembrane scaffolding protein expressed by melanophores and xanthophores. We further showed that dali mutant Tspan3c expressed in HeLa cell exhibits a defect in N‐glycosylation and is retained inappropriately in the endoplasmic reticulum. Our results are the first to identify roles for a tetraspanin superfamily protein in skin pigment pattern formation and suggest new mechanisms for the establishment and maintenance of zebrafish stripe boundaries.
Competency‐based Project to Review Community/Public Health Curricula
Authors: Schoneman Doris , Simandl Gladys , Hansen Judith M. , Garrett Sharon
Published: November 2013

Changes in the delivery of community/public health (C/PH) nursing have challenged nursing educators to seek innovative ways to ensure that their educational programs produce competent entry‐level practitioners. This article describes how public health professionals and faculty from eight regional colleges and universities in Southeastern Wisconsin came together to better understand both what C/PH nursing content was being taught in the region, and the extent to which that content was aligned with the Public Health Nurse Competencies defined by the Quad Council in 2004. Based on self‐reporting by nursing school faculty as well as a separate mapping of course objectives into the competency areas, the project found that the curricula of the participating colleges and universities adequately addressed most of the competencies in the Quad Council domains one through six. Competencies in domains seven (financial planning/management skills) and eight (leadership/systems thinking skills) were not, however, adequately addressed and plans were subsequently developed to fill those gaps. In addition to helping each institution identify strengths and gaps in its own curriculum, the project provided an unprecedented opportunity for both public health professionals and academics to build relationships, share best practices, and exchange resources.
Inactivation of Bacillus subtilis Spores Using Various Combinations of Ultraviolet Treatment with Addition of Hydrogen Peroxide
Authors: Zhang Yiqing , Zhou Lingling , Zhang Yongji , Tan Chaoqun
Published: November 2013

This study aims at comparing the inactivation of Bacillus subtilis spores by various combinations of UV treatment and hydrogen peroxide (H2O2) addition. The combinations included sequential (UV–H2O2, H2O2–UV) and simultaneous (UV/H2O2) processes. Results showed that B. subtilis spores achieved a certain inactivation effect through UV treatment. However, hardly any inactivation effect by H2O2 alone was observed. H2O2 had a significant synergetic effect when combined with UV treatment, while high irradiance and H2O2 concentration both favored the reaction. When treated with 0.60 mm H2O2 and 113.0 μW/cm2 UV irradiance for 6 min, the simultaneous UV/H2O2 treatment showed significantly improved disinfection effect (4.13 log) compared to that of UV–H2O2 (3.03 log) and H2O2–UV (2.88 log). The relationship between the inactivation effect and the exposure time followed a typical pseudo‐first‐order kinetics model. The pseudo‐first‐order rate constants were 0.478, 0.447 and 0.634 min−1, for the UV‐H2O2, H2O2–UV and UV/H2O2 processes, respectively, further confirming the optimal disinfection effect of the UV/H2O2 process. The disinfection could be ascribed to the OH radicals, as verified by the level of para‐chlorobenzoic acid (pCBA).
Immunology of experimental and natural human hookworm infection
Authors: Gaze S. , Bethony J. M. , Periago M. V.
Published: November 2013

Human hookworm infection is one amongst the most prevalent of the neglected tropical diseases. An informative experimental animal model, that is, one that parallels a human infection, is not available for the study of human hookworm infection. Much of our current understanding of the human immune response during hookworm infection relies on the studies from experimental infection of hookworm‐naïve individuals or the natural infections from individuals residing in hookworm‐endemic areas. The experimental human infections tend to be acute, dose‐controlled infections, often with a low larval inoculum so that they are well tolerated by human volunteers. Natural hookworm infections usually occur in areas where hookworm transmission is constant and infection is chronic. In cases where there has been drug administration in an endemic area, re‐infection often occurs quickly even amongst those who were treated. Hence, although many of the characteristics of experimental and natural hookworm infection differ, both models have elements in common: mainly an intense Th2 response with the production of total and specific IgE as well as elevated levels of eosinophilia, IL‐5, IL‐10 and TNF. While hookworm infection affects millions of individuals worldwide, much of the human immunology of this infection still needs to be studied and understood.
Does proximity to a mature forest contribute to the seed rain and recovery of an abandoned agriculture area in a semiarid climate?
Authors: Souza J. T. , Ferraz E. M. N. , Albuquerque U. P. , Araújo E. L.
Published: November 2013

Proximity to forests contributes to the recolonisation of anthropogenic‐disturbed areas through seed input. We evaluated the role of proximity to a mature forest in the recolonisation of an agricultural area that has been abandoned for 18 years and is currently a young forest. Seed rain was monitored at fixed distances from the mature forest. The type of surface recolonisation (germinationversusresprouting) and the reproductive season were measured in both forests. The majority of plants recolonising the young forest originated from seed germination. Proximity to the mature forest contributed to the seed rain in the young forest; however, 18 years has not provided sufficient time for the recolonisation of 80 species present in the mature forest. Some species shared between forests differed in their fruiting season and seed dispersal. The seed rain had a total species richness of 56, a total density of 2270 seeds·m−2·year−1and predominance of self‐ and wind dispersal. A significant reduction in seed rain with increasing distance from the mature forest was observed. The young forest contained 35 species not observed in the mature forest, and the floristic similarity between the two forests was 0.5, indicating that the two forests are floristically distinct.
Gravity‐dependent differentiation and root coils in Arabidopsis thaliana wild type and phospholipase‐A‐I knockdown mutant grown on the International Space Station
Authors: Scherer G. F. E. , Pietrzyk P.
Published: November 2013

Arabidopsis roots on 45° tilted agar in 1‐g grow in wave‐like figures. In addition to waves, formation of root coils is observed in several mutants compromised in gravitropism and/or auxin transport. The knockdown mutant ppla‐I‐1 of patatin‐related phospholipase‐A‐I is delayed in root gravitropism and forms increased numbers of root coils. Three known factors contribute to waving: circumnutation, gravisensing and negative thigmotropism. In microgravity, deprivation of wild type (WT) and mutant roots of gravisensing and thigmotropism and circumnutation (known to slow down in microgravity, and could potentially lead to fewer waves or increased coiling in both WT and mutant). To resolve this, mutant ppla‐I‐1 and WT were grown in the BIOLAB facility in the International Space Station. In 1‐g, roots of both types only showed waving. In the first experiment in microgravity, the mutant after 9 days formed far more coils than in 1‐g but the WT also formed several coils. After 24 days in microgravity, in both types the coils were numerous with slightly more in the mutant. In the second experiment, after 9 days in microgravity only the mutant formed coils and the WT grew arcuated roots. Cell file rotation (CFR) on the mutant root surface in microgravity decreased in comparison to WT, and thus was not important for coiling. Several additional developmental responses (hypocotyl elongation, lateral root formation, cotyledon expansion) were found to be gravity‐influenced. We tentatively discuss these in the context of disturbances in auxin transport, which are known to decrease through lack of gravity.
Risk of Transmission of Bovine Herpesvirus‐1 (BHV‐1) by Infected Semen to Embryo Recipients and Offspring
Authors: Bielanski A , Algire J , Lalonde A , Garceac A
Published: November 2013

Contents

Infection with bovine herpesvirus‐1 (BHV‐1), also called infectious bovine rhinotracheitis/infectious pustular vulvovaginitis virus, is associated with a variety of respiratory, neurological and infertility health problems causing worldwide economic losses and trading restrictions to the livestock industry. Although there is a considerable amount of information about the risk of BHV‐1 transmission through contaminated semen used for artificial insemination, there is no available evidence to indicate whether the resulting embryos, when used for embryo transfer (ET), can lead to the transmission of BHV‐1 to recipients and offspring. For this study, cryopreserved bull semen contaminated with BHV‐1 was used for artificial insemination (AI) of seronegative, superovulated heifers (N = 43). Embryos were collected post‐mortem at 7 days post‐insemination and were washed according to the International Embryo Transfer Society (IETS) guidelines. BHV‐1 was detected in all samples of follicular fluid, oviductal epithelial cells, endometrium and corpora lutea tissues and a proportion of unwashed (52 of 120, 43%) and washed oocytes and embryos (7 of 113, 6%) collected from embryo donors. Of the 396 collected, unfertilized oocytes and embryos, only 29 (7%) were of ET quality. Most of the embryos and oocytes were degenerated (N = 224, 57%) or unfertilized (N = 143, 36%). The 13 heifers, which each received a single morula‐stage washed embryo, maintained seronegative status, but only two (15%) became pregnant and delivered BHV‐1‐free calves. In conclusion, results suggest that embryos fertilized with BHV‐1‐contaminated semen may not result in disease transmission to embryo recipients or their offspring when embryos are processed according to IETS and the World Organization for Animal Health (OIE) guidelines. However, due to the transmission of BHV‐1 via AI to embryo donors and the apparent adverse effect of BHV‐1 on the quality of the embryos, it is unlikely that the procedure can be justified for a commercial application.
Information Structure, Syntax and Intonational Properties of MultipleWh‐Questions
Authors: Hosono Mayumi
Published: November 2013

I discuss multiplewh‐questions from the perspective of information structure. I argue that information‐structural effects differ between multiplewh‐questions with a pair‐list answer reading and ones with a single‐answer reading, thus the way of deriving them in narrow syntax differs too. I claim that the spelled‐out positions ofwh‐phrases are solely determined in the phonological component, specifically by the intonational properties of individual languages. I also argue that the Superiority Effect is derived from a conflicting pitch pattern caused by in‐situ monosyllabicwh‐subjects and no longer problematic in the current phase framework.
Successful high‐level accumulation of fish oil omega‐3 long‐chain polyunsaturated fatty acids in a transgenic oilseed crop
Authors: Ruiz‐Lopez Noemi , Haslam Richard P. , Napier Johnathan A. , Sayanova Olga
Published: November 2013

Omega‐3 (also called n‐3) long‐chain polyunsaturated fatty acids (≥C20; LC‐PUFAs) are of considerable interest, based on clear evidence of dietary health benefits and the concurrent decline of global sources (fish oils). Generating alternative transgenic plant sources of omega‐3 LC‐PUFAs, i.e. eicosapentaenoic acid (20:5 n‐3, EPA) and docosahexaenoic acid (22:6 n‐3, DHA) has previously proved problematic. Here we describe a set of heterologous genes capable of efficiently directing synthesis of these fatty acids in the seed oil of the crop Camelina sativa, while simultaneously avoiding accumulation of undesirable intermediate fatty acids. We describe two iterations: RRes_EPA in which seeds contain EPA levels of up to 31% (mean 24%), and RRes_DHA, in which seeds accumulate up to 12% EPA and 14% DHA (mean 11% EPA and 8% DHA). These omega‐3 LC‐PUFA levels are equivalent to those in fish oils, and represent a sustainable, terrestrial source of these fatty acids. We also describe the distribution of these non‐native fatty acids within C. sativa seed lipids, and consider these data in the context of our current understanding of acyl exchange during seed oil synthesis.
Improved chemical control of Conyza bonariensis in wheat limits problems in the following fallow
Authors: Walker Steven , Widderick Michael , McLean Andrew , Cook Tony , Davidson Bill
Published: November 2013

Conyza bonariensis is a major weed infesting zero‐tilled cropping systems in subtropical Australia, particularly in wheat and winter fallows. Uncontrolled C. bonariensis survives to become a problem weed in the following crops or fallows. As no herbicide has been registered for C. bonariensis in wheat, the effectiveness of 11 herbicides, currently registered for other broad‐leaved weeds in wheat, was evaluated in two pot and two field experiments. As previous research showed that the age of C. bonariensis, and to a lesser extent, the soil moisture at spraying affected herbicide efficacy, these factors also were investigated. The efficacy of the majority of herbicide treatments was reduced when large rosettes (5–15 cm diameter) were treated, compared with small rosettes (<5 cm diameter). However, for the majority of herbicide treatments, the soil moisture did not affect the herbicide efficacy in the pot experiments. In the field, a delay in herbicide treatment of 2 weeks reduced the herbicide efficacy consistently across herbicide treatments, which was related to weed age but not to soil moisture differences. Across all the experiments, four herbicides controlled C. bonariensis in wheat consistently (83–100%): 2,4‐D; aminopyralid + fluroxypyr; picloram + MCPA + metsulfuron; and picloram + high rates of 2,4‐D. Thus, this problem weed can be effectively and consistently controlled in wheat, particularly when small rosettes are treated, and therefore C. bonariensis will have a less adverse impact on the following fallow or crop.
An Experimental Assessment of the Effects of Stator Vane Tip Clearance Location and Back Swept Blading on an Automotive Variable Geometry Turbocharger
Authors: Walkingshaw Jason , Spence Stephen , Ehrhard Jan , Thornhill David
Published: November 2013

Off-design performance is of key importance now in the design of automotive turbocharger turbines. Due to automotive drive cycles, a turbine that can extract more energy at high pressure ratios and lower rotational speeds is desirable. Typically a radial turbine provides peak efficiency at U/C values of 0.7, but at high pressure ratios and low rotational speeds, the U/C value will be low and the rotor will experience high values of positive incidence at the inlet. The positive incidence causes high blade loading resulting in additional tip leakage flow in the rotor as well as flow separation on the suction surface of the blade. An experimental assessment has been performed on a scaled automotive VGS (variable geometry system). Three different stator vane positions have been analyzed: minimum, 25%, and maximum flow position. The first tests were to establish whether positioning the endwall clearance on the hub or shroud side of the stator vanes produced a different impact on turbine efficiency. Following this, a back swept rotor was tested to establish the potential gains to be achieved during off-design operation. A single passage CFD model of the test rig was developed and used to provide information on the flow features affecting performance in both the stator vanes and turbine. It was seen that off-design performance was improved by implementing clearance on the hub side of the stator vanes rather than on the shroud side. Through CFD analysis and tests, it was seen that two leakage vortices form, one at the leading edge and one after the spindle of the stator vane. The vortices affect the flow angle at the inlet to the rotor, in the hub region. The flow angle is shifted to more negative values of incidence, which is beneficial at the off-design conditions but detrimental at the design point. The back swept rotor was tested with the hub side stator vane clearance configuration. The efficiency and MFR were increased at the minimum and 25% stator vane position. At the design point, the efficiency and MFR were decreased. The CFD investigation showed that the incidence angle was improved at the off-design conditions for the back swept rotor. This reduction in the positive incidence angle, along with the improvement caused by the stator vane tip leakage flow, reduced flow separation on the suction surface of the rotor. At the design point, both the tip leakage flow of the stator vanes and the back swept blade angle caused flow separation on the pressure surface of the rotor. This resulted in additional blockage at the throat of the rotor reducing MFR and efficiency.
Impact of the MLC on the MRI field distortion of a prototype MRI‐linac
Authors: Kolling Stefan , Oborn Brad , Keall Paul
Published: November 2013

Purpose:

To cope with intrafraction tumor motion, integrated MRI‐linac systems for real‐time image guidance are currently under development. The multileaf collimator (MLC) is a key component in every state‐of‐the‐art radiotherapy treatment system, allowing for accurate field shaping and tumor tracking. This work quantifies the magnetic impact of a widely used MLC on the MRI field homogeneity for such a modality.

Methods:

The finite element method was employed to model a MRI‐linac assembly comprised of a split‐bore MRI magnet and the key ferromagnetic components of a Varian Millennium 120 MLC, namely, the leaves and motors. Full 3D magnetic field maps of the system were generated. From these field maps, the peak‐to‐peak distortion within the MRI imaging volume was evaluated over a diameter sphere volume (DSV) around the isocenter and compared to a maximum preshim inhomogeneity of . Five parametric studies were performed: (1) The source‐to‐isocenter distance (SID) was varied from 100 to , to span the range of a compact system to that with lower magnetic coupling. (2) The MLC model was changed from leaves only to leaves with motors, to determine the contribution to the total distortion caused by MLC leaves and motors separately. (3) The system was configured in the inline or perpendicular orientation, i.e., the linac treatment beam was oriented parallel or perpendicular to the magnetic field direction. (4) The treatment field size was varied from 0 × 0 to , to span the range of clinical treatment fields. (5) The coil currents were scaled linearly to produce magnetic field strengths B0 of 0.5, 1.0, and , to estimate how the MLC impact changes with B0.

Results:

(1) The MLC‐induced MRI field distortion fell continuously with increasing SID. (2) MLC leaves and motors were found to contribute to the distortion in approximately equal measure. (3) Due to faster falloff of the fringe field, the field distortion was generally smaller in the perpendicular beam orientation. The peak‐to‐peak DSV distortion was below at (perpendicular) and (inline) for the design. (4) The simulation of different treatment fields was identified to cause dynamic changes in the field distribution. However, the estimated residual distortion was below geometric distortion at (perpendicular) and (inline) for a frequency‐encoding gradient. (5) Due to magnetic saturation of the MLC materials, the field distortion remained constant at .

Conclusions:

This work shows that the MRI field distortions caused by the MLC cannot be ignored and must be thoroughly investigated for any MRI‐linac system. The numeric distortion values obtained for our magnet may vary for other magnet designs with substantially different fringe fields, however the concept of modest increases in the SID to reduce the distortion to a shimmable level is generally applicable.
Constancy of built‐in luminance meter measurements in diagnostic displays
Authors: Silosky M. , Marsh R. M.
Published: November 2013

Purpose:

Liquid crystal displays used to interpret medical images are often equipped with built‐in luminance meters to evaluate luminance response and Grayscale Standard Display Function conformance. This work evaluates agreement between luminance reported by the built‐in meters and external measurements.

Methods:

The white level luminance was measured using a built‐in meter and an external meter for 93 primary review workstations (Models MFGD 3420 and MDCG 3120‐CB) with between 117 and 49 336 backlight hours (BLH). Measured luminance values were compared viat‐test for displays with less than 25 000 BLH and those with more than 25 000 BLH. Bias between meters was also evaluated. Changes in luminance uniformity with increasing backlight hours were explored by determining the maximum luminance deviation (MLD) for subsets of these displays with less than 800 BLH and greater than 35 000 BLH.

Results:

The mean difference between built‐in and external luminance measurements was 5.84% and 38.92% for displays with less than 25 000 and greater than 25 000 BLH, respectively, with a statistically significant difference in the means (p < 0.001). For displays with low BLH, a statistically significant bias was observed (p < 0.001) between built‐in and external measurements. A high degree of correlation was observed between measurements made with two separate external meters (r = 0.999). The mean MLD was 9.5% and 11.2% for MDCG 3120‐CB displays with less than 800 and greater than 35 000 BLH, respectively. The difference in the mean values was not statistically significant (p < 0.001).

Conclusions:

Disagreement between the white level luminance measured using the built‐in and external meter increased with BLH. Consequently, reliance on values reported by the built‐in luminance meter may result in a reduction in image contrast with time. Recommendations have been proposed regarding luminance response testing and corrective action for failing displays.
Comparison and visualization of focusing wave fields from various time reversal techniques in elastic media
Authors: Anderson Brian E. , Ulrich Timothy J. , Le Bas Pierre-Yves
Published: November 2013

This Letter presents a series of time reversal experiments conducted on the surface of a fused silica glass block. Four different time reversal techniques are compared using three different imaging conditions. The techniques include two classical time reversal experiments: one with a pulse waveform source and one with an impulse response generated from a chirp signal. The other two techniques utilize the deconvolution, or inverse filter, signal processing methods for obtaining the signals to back propagate using a pulse waveform and an impulse response from a chirp. The max-in-time, symmetry, and energy current imaging conditions are compared.
Organization of the Mitotic Chromosome
Authors: Naumova Natalia , Imakaev Maxim , Fudenberg Geoffrey , Zhan Ye , Lajoie Bryan R. , Mirny Leonid A. , Dekker Job
Published: November 2013

Chromosome Conundrum

The three-dimensional organization of chromosomal DNA within the cell nucleus plays an important role in gene regulation.

Naumova
et al.

(p.
948
, published online 7 November; see the Perspective by

Kleckner
et al.

) used chromosome conformation capture-based methods in human tissue culture cells to analyze the higher order folding of human chromosomes across the cell cycle. During interphase the chromosomes showed locus-specific compart-mentalization. In mitotic cells, on the other hand, the chromosome organization was more linear, consistent with arrays of consecutive chromatin loops.
Molecular Architecture of a Eukaryotic Translational Initiation Complex
Authors: Fernández Israel S. , Bai Xiao-Chen , Hussain Tanweer , Kelley Ann C. , Lorsch Jon R. , Ramakrishnan V. , Scheres Sjors H. W.
Published: November 2013

Introduction

Initiation of protein synthesis is a key step in the control of gene expression. In eukaryotes, initiation is a highly complex process that requires almost a dozen protein factors. The last step involves joining of the large and small subunits of the ribosome to form the 80
S
initiation complex with the transfer RNA (tRNA) in the P-site base paired to the start codon. This step is catalyzed by the guanosine triphosphatase (GTPase) factor eIF5B. In addition, eIF5B is thought to play a role in ensuring that translation initiation takes place only on mature ribosomes.

Methods

The development of fast, direct electron detectors and new methods of image analysis for cryo–electron microscopy allow high-resolution reconstructions from much smaller numbers of particles than previously possible. We used these new methods to provide feedback to improve the biochemical preparation of samples for structure determination of the eukaryotic translation initiation complex with initiator tRNA and eIF5B, which was trapped on the ribosome with the nonhydrolyzable GTP analog GDPCP.

Results

Although the structure of the fully assembled complex was calculated from only 5143 particles, representing just 3% of the population in the sample, it was possible to obtain a resolution of 6.6 Å. This allowed us to propose a molecular model for the initiation complex. The structure shows that the subunits of the ribosome are rotated relative to the canonical state after initiation. The long helix and C-terminal domain of eIF5B have changed conformation and moved into the ribosome, where the C-terminal domain interacts with the initiator tRNA. The tRNA is stabilized in a distorted conformation, with its 3′-CCA end out of the peptidyl transferase center.

Discussion

The conformational change in eIF5B may be induced upon binding to the small (40
S
) subunit when it specifically recognizes initiator tRNA. In its altered conformation, eIF5B interacts simultaneously with the initiator tRNA and the GTPase center of the ribosome, thus coupling GTP hydrolysis with tRNA recognition in the ribosome. The large number of contacts made by eIF5B with the ribosomal subunits and tRNA is consistent with its role in subunit joining. A close contact with the eukaryote-specific ribosomal protein L40 would not be possible in the immature ubiquitinated form of L40, thus precluding the recruitment of immature 60
S
subunits. A comparison with previous work on the bacterial homolog IF2 suggests that the mechanism of this step of initiation is conserved across kingdoms. Finally, the use of recent advances in cryo-EM to determine a relatively high-resolution structure of the eIF5B-ribosome complex from a very small fraction of a sample could be a general approach for the study of other dynamic or transient biological complexes.
Chelyabinsk Airburst, Damage Assessment, Meteorite Recovery, and Characterization
Authors: Popova Olga P. , Jenniskens Peter , Emel’yanenko Vacheslav , Kartashova Anna , Biryukov Eugeny , Khaibrakhmanov Sergey , Shuvalov Valery , Rybnov Yurij , Dudorov Alexandr , Grokhovsky Victor I. , Badyukov Dmitry D. , Yin Qing-Zhu , Gural Peter S. , Albers Jim , Granvik Mikael , Evers Läslo G. , Kuiper Jacob , Kharlamov Vladimir , Solovyov Andrey , Rusakov Yuri S. , Korotkiy Stanislav , Serdyuk Ilya , Korochantsev Alexander V. , Larionov Michail Yu. , Glazachev Dmitry , Mayer Alexander E. , Gisler Galen , Gladkovsky Sergei V. , Wimpenny Josh , Sanborn Matthew E. , Yamakawa Akane , Verosub Kenneth L. , Rowland Douglas J. , Roeske Sarah , Botto Nicholas W. , Friedrich Jon M. , Zolensky Michael E. , Le Loan , Ross Daniel , Ziegler Karen , Nakamura Tomoki , Ahn Insu , Lee Jong Ik , Zhou Qin , Li Xian-Hua , Li Qiu-Li , Liu Yu , Tang Guo-Qiang , Hiroi Takahiro , Sears Derek , Weinstein Ilya A. , Vokhmintsev Alexander S. , Ishchenko Alexei V. , Schmitt-Kopplin Phillipe , Hertkorn Norbert , Nagao Keisuke , Haba Makiko K. , Komatsu Mutsumi , Mikouchi Takashi ,   (the Chelyabinsk Airburst Consortium)
Published: November 2013

Deep Impact?

On 15 February 2013, the Russian district of Chelyabinsk, with a population of more than 1 million, suffered the impact and atmospheric explosion of a 20-meter-wide asteroid—the largest impact on Earth by an asteroid since 1908.

Popova
et al.

(p.
1069
, published online 7 November; see the Perspective by

Chapman

) provide a comprehensive description of this event and of the body that caused it, including detailed information on the asteroid orbit and atmospheric trajectory, damage assessment, and meteorite recovery and characterization.
Observing the Dynamics of Dipole-Mediated Energy Transport by Interaction-Enhanced Imaging
Authors: Günter G. , Schempp H. , Robert-de-Saint-Vincent M. , Gavryusev V. , Helmrich S. , Hofmann C. S. , Whitlock S. , Weidemüller M.
Published: November 2013

Imaging Excitations

Complex processes such as chemical reactions and photosynthesis involve the transport of energy. The mechanisms of how the energy migrates, the influence of the surrounding environment, or the extent to which quantum mechanics affects the process remain unclear.

Günter
et al.

(p.
954
, published online 7 November; see the Perspective by

Donley

) found that a cloud of cold atoms suitably prepared and decorated with “impurity” Rydberg atoms could be used to image the transport of excitations between excited Rydberg atoms directly. This ability to tune the influence of the background environment may help in the study of the coherent transport of energy in complex many-body systems.
Complete Sequence of a New Bipartite Begomovirus Infecting Cotton Plants in Brazil
Authors: de Almeida Mariana Martins Severo , Jain Sona , Barroso Paulo Augusto Vianna , Hoffmann Lúcia Vieira , de Lucena Monaliza Gomes , Resende Renato de Oliveira , Inoue-Nagata Alice Kazuko
Published: November 2013

Begomoviruses are plant viruses responsible for severe losses in important crops, such as beans, cassavas, tomatoes, and cotton, around the world. Here, we report the first full-genome sequence of a bipartite begomovirus species collected from cotton plants in Brazil.
Draft Genome Sequence of the Antibiotic-Producing Epiphytic Isolate Pantoea ananatis BRT175
Authors: Smith Derek D. N. , Kirzinger Morgan W. B. , Stavrinides John
Published: November 2013

Pantoea
is a member of the
Enterobacteriaceae
, whose members have been shown to produce novel antibiotics. Here, we report the 4.8-Mb genome sequence of
Pantoea ananatis
strain BRT175, an epiphytic isolate from strawberries that produces an antibiotic that is effective against the fire blight pathogen,
Erwinia amylovora
.
Complete Genome Sequence of Leifsonia xyli subsp.
cynodontis
Strain DSM46306, a Gram-Positive Bacterial Pathogen of Grasses
Authors: Monteiro-Vitorello Claudia Barros , Zerillo Marcelo Marques , Van Sluys Marie-Anne , Camargo Luis Eduardo Aranha , Kitajima João Paulo
Published: November 2013

We announce the complete genome sequence of
Leifsonia xyli
subsp.
cynodontis
, a vascular pathogen of Bermuda grass. The species also comprises
Leifsonia xyli
subsp.
xyli
, a sugarcane pathogen. Since these two subspecies have genome sequences available, a comparative analysis will contribute to our understanding of the differences in their biology and host specificity.
Draft Genome Sequence of the Fish Pathogen Piscirickettsia salmonis
Authors: Eppinger Mark , McNair Katelyn , Zogaj Xhavit , Dinsdale Elizabeth A. , Edwards Robert A. , Klose Karl E.
Published: November 2013

Piscirickettsia salmonisis a Gram-negative intracellular fish pathogen that has a significant impact on the salmon industry. Here, we report the genome sequence ofP. salmonisstrain LF-89. This is the first draft genome sequence ofP. salmonis, and it reveals interesting attributes, including flagellar genes, despite this bacterium being considered nonmotile.
Draft Genome Sequence of
Nitrosospira
sp. Strain APG3, a Psychrotolerant Ammonia-Oxidizing Bacterium Isolated from Sandy Lake Sediment
Authors: Garcia Juan C. , Urakawa Hidetoshi , Le Vang Q. , Stein Lisa Y. , Klotz Martin G. , Nielsen Jeppe L.
Published: November 2013

Bacteria in the genus
Nitrosospira
play vital roles in the nitrogen cycle.
Nitrosospira
sp. strain APG3 is a psychrotolerant betaproteobacterial ammonia-oxidizing bacterium isolated from freshwater lake sediment. The draft genome revealed that it represents a new species of cluster 0
Nitrosospira
, which is presently not represented by described species.
Targeted exome capture and sequencing identifies novel PRPF31 mutations in autosomal dominant retinitis pigmentosa in Chinese families
Authors: Yang Liping , Yin Xiaobei , Wu Lemeng , Chen Ningning , Zhang Huirong , Li Genlin , Ma Zhizhong
Published: November 2013

Objectives

To identify disease-causing mutations in two Chinese families with autosomal dominant retinitis pigmentosa (adRP).

Design

Prospective analysis.

Patients

Two Chinese adRP families underwent genetic diagnosis. A specific hereditary eye disease enrichment panel (HEDEP) based on targeted exome capture technology was used to collect the protein coding regions of targeted 371 hereditary eye disease genes; high throughput sequencing was done with the Illumina HiSeq 2000 platform. The identified variants were confirmed with Sanger sequencing.

Setting

All experiments were performed in a large laboratory specialising in genetic studies in the Department of Ophthalmology, Peking University Third Hospital.

Results

Two novel mutations, including one splice site mutation (Int10 c.1074-2 A>T; p.Y359SfsX29) and one insertion (c.824_825insA; p.Y275X) of PRPF31 were identified in the two families. The two mutations segregated with the disease phenotype in their respective families.

Conclusions

Our findings broaden the spectrum of PRPF31 mutations causing adRP and the phenotypic spectrum of the disease in Chinese patients. The HEDEP based on targeted exome capture technology is an efficient method for molecular diagnosis in adRP patients.
Transcervical access in acute ischemic stroke
Authors: Jadhav Ashutosh P , Ribo Marc , Grandhi Ramesh , Linares Guillermo , Aghaebrahim Amin , Jovin Tudor G , Jankowitz Brian T
Published: November 2013

Background

Large vessel occlusive disease portends a poor prognosis unless recanalization is rapidly achieved. Endovascular treatment is typically performed via a transfemoral approach, but catheterization of the occluded vessel can be problematic in cases of extensive vessel tortuosity.

Methods

A retrospective review of a prospectively maintained database identified 7 patients who underwent acute endovascular reperfusion therapy via transcervical approach.

Results

We identified 7 patients. Admission NIHSS ranged from 8–27 and recanalization occurred between 7–49 min of carotid access. Prior to carotid access, 20–90 min were spent attempting target vessel catheterization via the transfemoral approach. All occlusions were in the left MCA. In 87.5% of patient, TICI2b/3 recanalization was achieved. Neck hematoma formation occurred in one case requiring elective intubation. At 2 months followup, all patients had survived with mRS 0–4 except for one patient who had a large infarct despite recanalization.

Conclusions

Transcervical access for acute ischemic stroke leads to rapid and high quality recanalization. Future studies will focus on improved hemostasis and early identification of patients who would benefit the most from direct carotid access for acute stroke.