bluuebunny/crossref_metadata_2025 huggingface dataset:
Structures of cyanobacteriochromes from phototaxis regulators AnPixJ and TePixJ reveal general and specific photoconversion mechanism
Authors: Narikawa Rei , Ishizuka Takami , Muraki Norifumi , Shiba Tomoo , Kurisu Genji , Ikeuchi Masahiko
Published: December 2012

Cyanobacteriochromes are cyanobacterial tetrapyrrole-binding photoreceptors that share a bilin-binding GAF domain with photoreceptors of the phytochrome family. Cyanobacteriochromes are divided into many subclasses with distinct spectral properties. Among them, putative phototaxis regulators PixJs of
Anabaena
sp. PCC 7120 and
Thermosynechococcus elongatus
BP-1 (denoted as AnPixJ and TePixJ, respectively) are representative of subclasses showing red-green-type and blue/green-type reversible photoconversion, respectively. Here, we determined crystal structures for the AnPixJ GAF domain in its red-absorbing 15
Z
state (Pr) and the TePixJ GAF domain in its green-absorbing 15
E
state (Pg). The overall structure of these proteins is similar to each other and also similar to known phytochromes. Critical differences found are as follows: (
i
) the chromophore of AnPixJ Pr is phycocyanobilin in a C5-
Z
,syn/C10-
Z
,syn/C15-
Z
,anti configuration and that of TePixJ Pg is phycoviolobilin in a C10-
Z
,syn/C15-
E
,anti configuration, (
ii
) a side chain of the key aspartic acid is hydrogen bonded to the tetrapyrrole rings A, B and C in AnPixJ Pr and to the pyrrole ring D in TePixJ Pg, (
iii
) additional protein-chromophore interactions are provided by subclass-specific residues including tryptophan in AnPixJ and cysteine in TePixJ. Possible structural changes following the photoisomerization of the chromophore between C15-
Z
and C15-
E
are discussed based on the X-ray structures at 1.8 and 2.0-Å resolution, respectively, in two distinct configurations.
In vivo translation rates can substantially delay the cotranslational folding of the
Escherichia coli
cytosolic proteome
Authors: Ciryam Prajwal , Morimoto Richard I. , Vendruscolo Michele , Dobson Christopher M. , O’Brien Edward P.
Published: December 2012

A question of fundamental importance concerning protein folding in vivo is whether the kinetics of translation or the thermodynamics of the ribosome nascent chain (RNC) complex is the major determinant of cotranslational folding behavior. This is because translation rates can reduce the probability of cotranslational folding below that associated with arrested ribosomes, whose behavior is determined by the equilibrium thermodynamics of the RNC complex. Here, we combine a chemical kinetic equation with genomic and proteomic data to predict domain folding probabilities as a function of nascent chain length for
Escherichia coli
cytosolic proteins synthesized on both arrested and continuously translating ribosomes. Our results indicate that, at in vivo translation rates, about one-third of the
Escherichia coli
cytosolic proteins exhibit cotranslational folding, with at least one domain in each of these proteins folding into its stable native structure before the full-length protein is released from the ribosome. The majority of these cotranslational folding domains are influenced by translation kinetics which reduces their probability of cotranslational folding and consequently increases the nascent chain length at which they fold into their native structures. For about 20% of all cytosolic proteins this delay in folding can exceed the length of the completely synthesized protein, causing one or more of their domains to switch from co- to posttranslational folding solely as a result of the in vivo translation rates. These kinetic effects arise from the difference in time scales of folding and amino-acid addition, and they represent a source of metastability in
Escherichia coli
's proteome.
Using digital technologies to support Self‐Directed Learning for preservice teacher education
Authors: Bullock Shawn Michael
Published: December 2012

This article begins with the perspective that teacher education programmes are cultural institutions and are thus compelled to respond to the societal push for teachers to be conversant in so‐called twenty‐first‐century skills, grounded primarily in the ability to use digital technologies for pedagogical purposes. The results of an attempt to provide teacher candidates with an opportunity to engage in a sustained self‐directed learning experience using digital technologies are presented. Findings indicate that candidates selected tasks for themselves for both personal and pragmatic reasons, and that external pressures played a significant role in candidates' ability to see their tasks through to satisfactory completion. The focus on self‐directed learning provided me with an opportunity to address some pragmatic concerns raised by the perceived need to teach technology skills in a teacher education course while, more importantly, providing an atypical learning experience that encouraged teacher candidates to engage in metacognitive talk about their experiences learning with and through technology. The article concludes by suggesting that self‐directed learning experiences are worthwhile in teacher education, although experiences framed explicitly around digital technologies may tacitly reinforce a positive bias toward using technology for teaching.
Protracted Outbreak of Multidrug-ResistantAcinetobacter baumanniiafter Intercontinental Transfer of Colonized Patients
Authors: Landelle Caroline , Legrand Patrick , Lesprit Philippe , Cizeau Florence , Ducellier David , Gouot Cyril , Bréhaut Paula , Soing-Altrach Sophan , Girou Emmanuelle , Brun-Buisson Christian
Published: December 2012

Objective.

To describe the course and management of a protracted outbreak after intercontinental transfer of 2 patients colonized with multidrug-resistantAcinetobacter baumannii(MDRAB).

Design.

An 18-month outbreak investigation.

Setting.

An 860-bed university hospital in France.

Patients.

Case patients (ie, carriers) were those colonized or infected with an MDRAB isolate.

Methods.

During the epidemic period, all intensive care unit (ICU) patients and contacts of carriers who were transferred to wards were screened for MDRAB carriage. Contact precautions, environmental screening, and auditing of healthcare worker (HCW) practices were implemented; rooms were cleaned with hydrogen peroxide mist disinfection. One ICU, in which most of the cases occurred, was closed on 4 occasions for thorough cleaning and disinfection.

Results.

The 2 index case patients were identified as 2 patients who carried the same MDRAB strain and who were admitted to the hospital after repatriation from Tahiti 5 months apart. During an 18-month period, a total of 84 secondary cases occurred. Reintroduction of MDRAB into the ICUs occurred from patients previously colonized or from healthcare personnel. Termination of the outbreak was only achieved when all carriers from wards or the ICU were cohorted to an isolation unit with dedicated healthcare personnel.

Conclusions.

Intercontinental transfer of carriers of MDRAB can result in extensive outbreaks and serious disruption of the hospital's organization. Transmission from carriers most likely occurred via the hands of HCWs, poor cleaning protocols, airborne spread, and contaminated water from sink traps. This protracted outbreak was controlled only after implementation of an extensive control program and eventual cohorting of all carriers in an isolation unit with dedicated healthcare personnel.
music for Faraday rotation measure synthesis
Authors: Andrecut M.
Published: December 2012

Faraday rotation measure (RM) synthesis requires the recovery of the Faraday dispersion function (FDF) from measurements restricted to limited wavelength ranges, which is an ill-conditioned deconvolution problem. Here, we propose a novel deconvolution method based on an extension of the MUltiple SIgnal Classification (music) algorithm. The complexity and speed of the method is determined by the eigen-decomposition of the covariance matrix of the observed polarizations. We show numerically that for high to moderate signal-to-noise ratio (S/N) cases the rm-music method is able to recover the Faraday depth values of closely spaced pairs of thin RM components, even in situations where the peak response of the FDF is outside of the RM range between the two input RM components. This result is particularly important because the standard deconvolution approach based on rm-clean fails systematically in such situations, due to its greedy mechanism used to extract the RM components. For low S/N situations, both the rm-music and rm-clean methods provide similar results.
Effects of Divided Attention and Operating Room Noise on Perception of Pulse Oximeter Pitch Changes
Authors: Stevenson Ryan A. , Schlesinger Joseph J. , Wallace Mark T.
Published: December 2012

Background:

Anesthesiology requires performing visually oriented procedures while monitoring auditory information about a patient’s vital signs. A concern in operating room environments is the amount of competing information and the effects that divided attention has on patient monitoring, such as detecting auditory changes in arterial oxygen saturation via pulse oximetry.

Methods:

The authors measured the impact of visual attentional load and auditory background noise on the ability of anesthesia residents to monitor the pulse oximeter auditory display in a laboratory setting. Accuracies and response times were recorded reflecting anesthesiologists’ abilities to detect changes in oxygen saturation across three levels of visual attention in quiet and with noise.

Results:

Results show that visual attentional load substantially affects the ability to detect changes in oxygen saturation concentrations conveyed by auditory cues signaling 99 and 98% saturation. These effects are compounded by auditory noise, up to a 17% decline in performance. These deficits are seen in the ability to accurately detect a change in oxygen saturation and in speed of response.

Conclusions:

Most anesthesia accidents are initiated by small errors that cascade into serious events. Lack of monitor vigilance and inattention are two of the more commonly cited factors. Reducing such errors is thus a priority for improving patient safety. Specifically, efforts to reduce distractors and decrease background noise should be considered during induction and emergence, periods of especially high risk, when anesthesiologists has to attend to many tasks and are thus susceptible to error.
A Single-nucleotide Polymorphism in SCN9A May Decrease Postoperative Pain Sensitivity in the General Population
Authors: Duan Guangyou , Xiang Guifang , Zhang Xianwei , Yuan Ruimei , Zhan Huiming , Qi Dongmei
Published: December 2012

Background:

This study aimed to explore the role of a nonsynonymous single-nucleotide polymorphism, 3312G>T, in SCN9A, which was identified in probands with congenital indifference to pain, but which is also present in normal controls, in the prediction of individual baseline pain perception, and postoperative pain sensitivity in the general population.

Methods:

Preoperative pressure pain thresholds and tolerance were measured in 200 patients undergoing pancreatectomy, and the postoperative pain sensitivity and analgesic demand were recorded. These variables were compared according to the SCN9A 3312G>T alleles. Logistic regression analysis was used to test the role of preoperative variables in the prediction of postoperative inadequate analgesia.

Results:

The 3312Tallele was present in 22 individuals, and the 3312Tallele frequency was 5.5% (22/200). The average patient-controlled analgesia pressing frequency and opioid consumption in 3312G patients was significantly higher than those in 3312T patients (2.70 [SD: 0.84] vs. 2.05 [SD: 0.43], P < 0.001; 100.8 [SD: 40.7] vs. 74.8 [SD: 20.8] ml, P = 0.006). The incidence of inadequate analgesia in 3312G patients was significantly higher than that of patients carrying the 3312Tallele (29.2% vs. 4.5%; P = 0.013). Carrying the 3312Tallele and having a higher pressure pain threshold predicted a lower risk of postoperative inadequate analgesia, with an odds ratio of 0.10 (95% CI: 0.01 to 0.76, P = 0.026) and 0.32 (95% CI: 0.13 to 0.82, P = 0.018), respectively.

Conclusion:

Patients carrying the SCN9A 3312Tallele presented with lower postoperative pain sensitivity in the presence of a similar surgical pain stimulus, and had a lower likelihood of developing inadequate analgesia than those carrying the 3312Gallele.
Formation of (Fe,Cr) carbides and dislocation structures in low-chromium steel studiedin situusing synchrotron radiation
Authors: Dere E. Gözde , Sharma Hemant , Huizenga Richard M. , Portale Giusseppe , Bras Wim , Bliznuk Vitaliy , Sietsma Jilt , Offerman S. Erik
Published: December 2012

The evolution of the size distribution of (Fe,Cr) carbides and the dislocation structure in low-chromium steel is studied during quenching and rapid heating byin situsmall-angle X-ray scattering (SAXS). The two-dimensional SAXS patterns consist of streaks on top of an isotropic SAXS signal. The evolution of the size distribution of the (Fe,Cr) carbides during heat treatment is determined from the isotropic component of the SAXS patterns. The isotropic part of the SAXS patterns shows that, after austenitization and quenching to room temperature, the average precipitate radius is 4.74 nm and the dispersion parameter for the lognormal size distribution is 0.33. Subsequent rapid heating to 823 K results in an average precipitate size of 5.25 nm and a dispersion parameter of 0.26. Bright-field transmission electron microscopy and high-resolution transmission electron microscopy reveal the nearly spherical morphology of the precipitates. The microstructural evolution underlying the increase in the average precipitate size and the decrease in the dispersion parameter after heating to and annealing at 823 K is probably that at room temperature two types of precipitates are present,i.e.(Fe,Cr)23C6and (Fe,Cr)7C3precipitates according to thermodynamic calculations, and at 823 K only (Fe,Cr)7C3precipitates are present. Additional measurements have been carried out on a single crystal of ferrite containing (Fe,Cr) carbides by combining three-dimensional X-ray diffraction (3DXRD) and SAXS during rotation of the specimen at room temperature, in order to investigate the origin of the streaks at low angles in the SAXS pattern. From simulations based on the theory of SAXS from dislocations, it is shown that the measured streaks, including the spottiness, in the two-dimensional SAXS patterns correspond to a dislocation structure of symmetric low-angle tilt boundaries, which in turn corresponds to the crystallographic orientation gradient in the single crystal of ferrite as measured by 3DXRD microscopy.
A high-pressure cryocooling method for protein crystals and biological samples with reduced background X-ray scatter
Authors: Kim Chae Un , Wierman Jennifer L. , Gillilan Richard , Lima Enju , Gruner Sol M.
Published: December 2012

High-pressure cryocooling has been developed as an alternative method for cryopreservation of macromolecular crystals and successfully applied for various technical and scientific studies. The method requires the preservation of crystal hydration as the crystal is pressurized with dry helium gas. Previously, crystal hydration was maintained either by coating crystals with a mineral oil or by enclosing crystals in a capillary which was filled with crystallization mother liquor. These methods are not well suited to weakly diffracting crystals because of the relatively high background scattering from the hydrating materials. Here, an alternative method of crystal hydration, called capillary shielding, is described. The specimen is kept hydratedviavapor diffusion in a shielding capillary while it is being pressure cryocooled. After cryocooling, the shielding capillary is removed to reduce background X-ray scattering. It is shown that, compared to previous crystal-hydration methods, the new hydration method produces superior crystal diffraction with little sign of crystal damage. Using the new method, a weakly diffracting protein crystal may be properly pressure cryocooled with little or no addition of external cryoprotectants, and significantly reduced background scattering can be observed from the resulting sample. Beyond the applications for macromolecular crystallography, it is shown that the method has great potential for the preparation of noncrystalline hydrated biological samples for coherent diffraction imaging with future X-ray sources.
A preferred orientation correction to describe a fiber texture under glancing incidence
Authors: Simeone David , Gosset Dominique , Baldinozzi Gianguido
Published: December 2012

Much work is nowadays being devoted to the characterization of the structure and the microstructure of thin films and mesoporous materials. Different physical and chemical processes used to elaborate these thin films often induce a fiber texture in these materials. The X-ray glancing-incidence technique appears to be a useful tool for collecting diffraction patterns of thin films while avoiding the peaks of the substrate. However, the scattering vector in this asymmetric scattering geometry is not perpendicular to the surface of the sample. This point implies that the correction developed to model the effects of a fiber texture in Bragg–Brentano geometry, where the scattering vector is always normal to the surface of the sample, cannot be applied in glancing incidence. This work presents a procedure to correct the preferred orientation due to this fiber texture in asymmetric scattering geometry and then in glancing incidence. By an example, it is proved that this correction of the fiber texture is efficient. The main point of interest regarding this correction is that only a few parameters are needed to handle the effect of the fiber texture on the diffraction patterns collected in asymmetric scattering geometry and then under glancing incidence.
{111}-specific twinning structures in nonstoichiometric ZrC0.6with ordered carbon vacancies
Authors: Hu Wentao , Liu Shaocun , Wen Bin , Xiang Jianyong , Wen Fusheng , Xu Bo , He Julong , Yu Dongli , Tian Yongjun , Liu Zhongyuan
Published: December 2012

Twinning structures in ordered nonstoichiometric ZrC0.6have been investigated experimentally and theoretically.Viatransmission electron microscopy and selected area electron diffraction measurements, {111}-specific twins have been observed. Interestingly, two special types of twinning interfaces,i.e.(111)Cand (111)Zrinterfaces, are recognized to be formed as a result of the presence of ordered carbon vacancies. In contrast to the high stacking fault energy for twinning formation in stoichiometric ZrC, first-principles calculations indicate that the presence of ordered carbon vacancies leads to a great reduction in the twinning interfacial energy, thus favouring the stabilization of twinning structures in the ordered ZrC0.6.
Microtribological Behavior of W-S-C Films Deposited by Different Sputtering Procedures
Authors: Tomastik C. , Pauschitz A. , Roy M.
Published: December 2012

Tungsten sulfide is a transition metal dichalcogenide (TMD) with excellent self-lubricating properties, and a potential candidate for coatings for MEMS applications. Its mechanical and tribological properties can be further improved by alloying it with carbon (W-S-C films). These films are commonly manufactured by sputter deposition. The present work investigates the influence of sputtering procedure on the microtribological performance of W-S-C films. For this purpose, carbon was incorporated in the films via three different ways: (1) by using a reactive gas (CH4); (2) by co-sputtering from two separate targets (WS2 and C); and (3) by sputtering from a composite target of graphite embedded with WS2 pellets. The films were characterized with scanning electron microscopy (SEM), nanoindentation, atomic force microscopy (AFM), and micro-Raman spectroscopy (RS). Reciprocating wear tests were performed on a microtribometer with steel balls as counterbodies. The worn surfaces were investigated with white light confocal microscopy, RS, and X-ray photoelectron spectroscopy (XPS). The results show that the total wear decreases with the hardness of the investigated films and increases with applied load of the tribological test. The friction coefficient at higher load is governed by the roughness of the films. At low load, the presence of graphitic carbon determines the friction coefficient. No transfer of material from the counteracting body is observed.
3D FE Modeling Simulation for Wear in Cold Rotary Forging of 20CrMnTi Alloy
Authors: Han Xinghui , Hua Lin
Published: December 2012

Cold rotary forging is an advanced but complicated metal forming technology with continuous local plastic deformation. Investigating the wear is significant for effectively predicting the life of the dies and improving the workpiece surface quality. This paper is aimed to use the FE method to predict the wear response over the surfaces of the dies and the workpiece in cold rotary forging. For this purpose, a 3D elastic-plastic dynamic explicit FE model of cold rotary forging of 20CrMnTi alloy is developed using the FE software ABAQUS/Explicit and its validity is verified theoretically and analytically. Based on this valid 3D FE model, a systematic study has first been conducted, modeling and explaining the contact pressure and slip distance response. Then, the wear response that occurs at the surfaces of the dies and the workpiece is achieved. Finally, the effect of the process parameters, rotational speed n of the upper die, feed rate v of the lower die, outer/inner diameter of the ring workpiece, on the wear response is revealed. The results of this research help us better understand the complicated wear mechanisms in cold rotary forging. Moreover, the modeling methods proposed in this paper have the general significance to study the wear problems in other complicated metal forming processes.
Projection imaging of photon beams by the Čerenkov effect
Authors: Glaser Adam K. , Davis Scott C. , McClatchy David M. , Zhang Rongxiao , Pogue Brian W. , Gladstone David J.
Published: December 2012

Purpose:

A novel technique for beam profiling of megavoltage photon beams was investigated for the first time by capturing images of the induced Čerenkov emission in water, as a potential surrogate for the imparted dose in irradiated media.

Methods:

A high‐sensitivity, intensified CCD camera (ICCD) was configured to acquire 2D projection images of Čerenkov emission from a 4 × 4 cm2 6 MV linear accelerator (LINAC) x‐ray photon beam operating at a dose rate of 400 MU/min incident on a water tank with transparent walls. The ICCD acquisition was gated to the LINAC sync pulse to reduce background light artifacts, and the measurement quality was investigated by evaluating the signal to noise ratio and measurement repeatability as a function of delivered dose. Monte Carlo simulations were used to derive a calibration factor for differences between the optical images and deposited dose arising from the anisotropic angular dependence of Čerenkov emission. Finally, Čerenkov‐based beam profiles were compared to a percent depth dose (PDD) and lateral dose profile at a depth of dmax from a reference dose distribution generated from the clinical Varian ECLIPSE treatment planning system (TPS).

Results:

The signal to noise ratio was found to be 20 at a delivered dose of 66.6 cGy, and proportional to the square root of the delivered dose as expected from Poisson photon counting statistics. A 2.1% mean standard deviation and 5.6% maximum variation in successive measurements were observed, and the Monte Carlo derived calibration factor resulted in Čerenkov emission images which were directly correlated to deposited dose, with some spatial issues. The dose difference between the TPS and PDD predicted by Čerenkov measurements was within 20% in the buildup region with a distance to agreement (DTA) of 1.5–2 mm and ±3% at depths beyonddmax. In the lateral profile, the dose difference at the beam penumbra was within ±13% with a DTA of 0–2 mm, ±5% in the central beam region, and 2%–3% in the beam umbra.

Conclusions:

The results from this initial study demonstrate the first documented use of Čerenkov emission imaging to profile x‐ray photon LINAC beams in water. The proposed modality has several potential advantages over alternative methods, and upon future refinement may prove to be a robust and novel dosimetry method.
Radiometry and the Friis transmission equation
Authors: Shaw Joseph A.
Published: December 2012

To more effectively tailor courses involving antennas, wireless communications, optics, and applied electromagnetics to a mixed audience of engineering and physics students, the Friis transmission equation—which quantifies the power received in a free-space communication link—is developed from principles of optical radiometry and scalar diffraction. This approach places more emphasis on the physics and conceptual understanding of the Friis equation than is provided by the traditional derivation based on antenna impedance. Specifically, it shows that the wavelength-squared dependence can be attributed to diffraction at the antenna aperture and illustrates the important difference between the throughput (product of area and solid angle) of a single antenna or telescope and the throughput of a transmitter-receiver pair.
Energy and momentum entanglement in parametric downconversion
Authors: Saldanha Pablo L. , Monken C. H.
Published: December 2012

We present a simple treatment of the phenomenon of spontaneous parametric downconversion consisting of the coherent scattering of a single pump photon into an entangled photon pair inside a nonlinear crystal. The energy and momentum entanglement of the quantum state of the generated twin photons are seen as a consequence of the fundamental indistinguishability of the time and the position in which the photon pair is created inside the crystal. We also discuss some consequences of photon entanglement.
Symmetry-Protected Topological Orders in Interacting Bosonic Systems
Authors: Chen Xie , Gu Zheng-Cheng , Liu Zheng-Xin , Wen Xiao-Gang
Published: December 2012

Symmetry Semantics

Topological insulators (TIs) are characterized by boundary states that are protected by time-reversal symmetry. A systematic study of this, and other symmetry-protected states, is possible in noninteracting systems, but complications arise when interactions are present.

Chen
et al.

(p.
1604
; see the Perspective by

Qi

) used group cohomology theory to predict symmetry-protected phases of interacting bosons. The analysis enabled the generalization of a known result in one dimension by using a path-integral formulation and suggests the existence of three counterparts of TIs in three dimensions, and one in two dimensions, as well as phases protected by other symmetries. The formalism is applicable to any symmetry group and dimension and is valid for interactions of arbitrary strength.
Cardiac Regeneration
Authors: Rosenzweig Anthony
Published: December 2012

The heart has greater potential for repair than once appreciated—whether this can be exploited clinically remains an open question.
Modeling the Formation of Porphyry-Copper Ores
Authors: Ingebritsen Steven E.
Published: December 2012

Dynamic changes in the permeability of Earth's crust are needed to account for the formation of porphyry-copper ores from magmatic fluids.
Splicing in 4D
Authors: Papasaikas Panagiotis , Valcárcel Juan
Published: December 2012

Flexibility in regulating RNA splicing can generate diverse phenotypic differences among equivalent organs across vertebrates.
Remember—You Will Die
Death
A Self-Portrait

assembled by Richard Harris

Wellcome Collection, London. Through 24 February 2013. www.wellcomecollection.org/death
Authors: Ash Caroline
Published: December 2012

The exhibition spotlights Harris's collection "devoted to the iconography of death and our … attitudes towards it."
Nematode Asparaginyl-tRNA Synthetase Resolves Intestinal Inflammation in Mice with T-Cell Transfer Colitis
Authors: Kron Michael A. , Metwali Ahmed , Vodanovic-Jankovic Sanja , Elliott David
Published: December 2012

The therapeutic effects of a controlled parasitic nematode infection on the course of inflammatory bowel disease (IBD) have been demonstrated in both animal and human models. However, the inability of individual well-characterized nematode proteins to recreate these beneficial effects has limited the application of component immunotherapy to human disease. The nematodes that cause chronic human lymphatic filariasis,
Brugia malayi
and
Wuchereria bancrofti
, are among the parasites that induce immune suppression. Filarial lymphatic pathology has been shown to involve NF-κB pathway-dependent production of vascular endothelial growth factor (VEGF), and stimulation of VEGF expression has also been reported by interleukin 8 (IL-8) via NF-κB pathways. Previously, we have shown that the filarial asparaginyl-tRNA synthetase (rBmAsnRS) interacts with IL-8 receptors using a combination of extracellular loops that differ from those bound by IL-8. To test the hypothesis that rBmAsnRS might induce an anti-inflammatory effect
in vivo
, we studied the effects of rBmAsnRS in an established murine colitis model using T-cell transfer mice. T-cell transfer colitis mice treated intraperitoneally with 100 μg of rBmAsnRS four times over 2 weeks showed resolution of cellular infiltration in the colonic mucosa, along with induction of a CD8
+
cellular response. In addition, rBmAsnRS induced a rise in IL-10 production from CD3
+
and lipopolysaccharide (LPS)- and cytosine phosphate guanosine (CPG)-stimulated splenic cells. In summary, this work demonstrates a novel anti-inflammatory nematode protein, supports the hygiene hypothesis, and supports continued refinement of alternative immunotherapies for treatment of IBD.
Pseudo-Outbreak of Vancomycin-Resistant-Enterococcus (VRE) Colonization in a Neonatal Intensive Care Unit Using Spectra VRE Surveillance Medium
Authors: Gander Rita M. , Cavuoti Dominick , Alatoom Adnan , Southern Paul , Grant Debra , Salinas Kathleen , Gaffney Donna , MacKenzie Jennifer , Byrd Linda
Published: December 2012

From November 2011 through March 2012, we surveyed 272 babies in our neonatal intensive care unit for rectal colonization with vancomycin-resistant enterococci (VRE). Using Spectra VRE medium (Remel Diagnostics, Lenexa, KS), we identified one neonate colonized with vancomycin-resistantEnterococcus faecium. In addition, 55 (13%) of the surveillance cultures yielded false-positive results with vancomycin-susceptibleEnterococcus faecalis. During the same time period, 580 rectal swabs were collected from adult patients resulting in 20 (3%) false-positive cultures. The difference in false-positive rates between cultures from babies and adults was statistically significant (P< 0.001), prompting an investigation of factors that might influence the elevated false-positive rate in the neonates including patient demographics, nutrition, and topical ointments applied at the time of testing. Older neonates, with a median age of 6 weeks, were more likely to have false-positive cultures than younger neonates with a median age of 3 weeks (P< 0.001). The younger neonates receiving Similac Expert Care products were less likely to have false-positive surveillance cultures than those receiving other formulas (P< 0.001). Application of topical products was not associated with false-positive cultures. The false-positiveE. faecalisstrains were typed by Diversilab Rep-PCR (bioMérieux, Marcy l'Etoile, France) and found to represent eight different groups of isolates. The utility of the Spectra VRE media appeared to be significantly impacted by the age of the patients screened.
Contribution of Double-Stranded RNA and CPSF30 Binding Domains of Influenza Virus NS1 to the Inhibition of Type I Interferon Production and Activation of Human Dendritic Cells
Authors: Ramos Irene , Carnero Elena , Bernal-Rubio Dabeiba , Seibert Christopher W. , Westera Liset , García-Sastre Adolfo , Fernandez-Sesma Ana
Published: December 2012

The influenza virus nonstructural protein 1 (NS1) inhibits innate immunity by multiple mechanisms. We previously reported that NS1 is able to inhibit the production of type I interferon (IFN) and proinflammatory cytokines in human primary dendritic cells (DCs). Here, we used recombinant viruses expressing mutant NS1 from the A/Texas/36/91 and A/Puerto Rico/08/34 strains in order to analyze the contribution of different NS1 domains to its antagonist functions. We show that the polyadenylation stimulating factor 30 (CPSF30) binding function of the NS1 protein from A/Texas/36/91 influenza virus, which is absent in the A/Puerto Rico/08/34 strain, is essential for counteracting these innate immune events in DCs. However, the double-stranded RNA (dsRNA) binding domain, present in both strains, specifically inhibits the induction of type I IFN genes in infected DCs, while it is essential only for inhibition of type I IFN proteins and proinflammatory cytokine production in cells infected with influenza viruses lacking a functional CPSF30 binding domain, such as A/Puerto Rico/08/34.
Cellular Entry of Human Papillomavirus Type 16 Involves Activation of the Phosphatidylinositol 3-Kinase/Akt/mTOR Pathway and Inhibition of Autophagy
Authors: Surviladze Zurab , Sterk Rosa T. , DeHaro Sergio A. , Ozbun Michelle A.
Published: December 2012

The mammalian target of rapamycin (mTOR) downstream of phosphatidylinositol 3-kinase (PI3K) in the growth factor receptor (GFR) pathway is a crucial metabolic sensor that integrates growth factor signals in cells. We recently showed that human papillomavirus (HPV) type 16 exposure activates signaling from GFRs in human keratinocytes. Thus, we predicted that the virus would induce the PI3K/mTOR pathway upon interaction with host cells. We detected activation of Akt and mTOR several minutes following exposure of human keratinocytes to HPV type 16 (HPV16) pseudovirions. Activated mTOR induced phosphorylation of the mTOR complex 1 substrates 4E-BP1 and S6K, which led to induction of the functional protein translational machinery. Blockade of epidermal GFR (EGFR) signaling revealed that each of these events is at least partially dependent upon EGFR activation. Importantly, activation of PI3K/Akt/mTOR signaling inhibited autophagy in the early stages of virus-host cell interaction. Biochemical and genetic approaches revealed critical roles for mTOR activation and autophagy suppression in HPV16 early infection events. In summary, the HPV-host cell interaction stimulates the PI3K/Akt/mTOR pathway and inhibits autophagy, and in combination these events benefit virus infection.
Differential Targeting of Viral Components by CD4+versus CD8+T Lymphocytes in Dengue Virus Infection
Authors: Rivino Laura , Kumaran Emmanuelle A. P. , Jovanovic Vojislav , Nadua Karen , Teo En Wei , Pang Shyue Wei , Teo Guo Hui , Gan Victor Chih Hao , Lye David C. , Leo Yee Sin , Hanson Brendon J. , Smith Kenneth G. C. , Bertoletti Antonio , Kemeny David M. , MacAry Paul A.
Published: December 2012

Dengue virus (DENV) is the principal arthropod-borne viral pathogen afflicting human populations. While repertoires of antibodies to DENV have been linked to protection or enhanced infection, the role of T lymphocytes in these processes remains poorly defined. This study provides a comprehensive overview of CD4+and CD8+T cell epitope reactivities against the DENV 2 proteome in adult patients experiencing secondary DENV infection. Dengue virus-specific T cell responses directed against an overlapping 15mer peptide library spanning the DENV 2 proteome were analyzedex vivoby enzyme-linked immunosorbent spot assay, and recognition of individual peptides was further characterized in specific T cell lines. Thirty novel T cell epitopes were identified, 9 of which are CD4+and 21 are CD8+T cell epitopes. We observe that whereas CD8+T cell epitopes preferentially target nonstructural proteins (NS3 and NS5), CD4+epitopes are skewed toward recognition of viral components that are also targeted by B lymphocytes (envelope, capsid, and NS1). Consistently, a large proportion of dengue virus-specific CD4+T cells have phenotypic characteristics of circulating follicular helper T cells (CXCR5 expression and production of interleukin-21 or gamma interferon), suggesting that they are interacting with B cellsin vivo. This study shows that during a dengue virus infection, the protein targets of human CD4+and CD8+T cells are largely distinct, thus highlighting key differences in the immunodominance of DENV proteins for these two cell types. This has important implications for our understanding of how the two arms of the human adaptive immune system are differentially targeted and employed as part of our response to DENV infection.
Antioxidant Treatment Regulates the Humoral Immune Response during Acute Viral Infection
Authors: Crump Katie E. , Langston P. Kent , Rajkarnikar Sujana , Grayson Jason M.
Published: December 2012

Generation of reactive oxygen intermediates (ROI) following antigen receptor ligation is critical to promote cellular responses. However, the effect of antioxidant treatment on humoral immunity during a viral infection was unknown. Mice were infected with lymphocytic choriomeningitis virus (LCMV) and treated with Mn(III)tetrakis(4-benzoic acid)porphyrin chloride (MnTBAP), a superoxide dismutase mimetic, from days 0 to 8 postinfection. On day 8, at the peak of the splenic response in vehicle-treated mice, virus-specific IgM and IgG antibody-secreting cells (ASC) were decreased 22- and 457-fold in MnTBAP-treated animals. By day 38, LCMV-specific IgG ASC were decreased 5-fold in the bone marrow of drug-treated mice, and virus-specific antibodies were of lower affinity. Interestingly, antioxidant treatment had no effect on the number of LCMV-specific IgG memory B cells. In addition to decreases in ASC, MnTBAP treatment decreased the number of functional virus-specific CD4
+
T cells. The decreased numbers of ASC observed on day 8 in drug-treated mice were due to a combination of Bim-mediated cell death and decreased proliferation. Together, these data demonstrate that ROI regulate antiviral ASC expansion and have important implications for understanding the effects of antioxidants on humoral immunity during infection and immunization.
The influence of the food environment on overweight and obesity in young children: a systematic review
Authors: Osei-Assibey George , Dick Smita , Macdiarmid Jennie , Semple Sean , Reilly John J , Ellaway Anne , Cowie Hilary , McNeill Geraldine
Published: December 2012

Background and objective

The increasing prevalence of childhood obesity has led to interest in its prevention, particularly through school-based and family-based interventions in the early years. Most evidence reviews, to date, have focused on individual behaviour change rather than the ‘obesogenic environment’.

Objective

This paper reviews the evidence on the influence of the food environment on overweight and obesity in children up to 8 years.

Data sources

Electronic databases (including MEDLINE, EMBASE, Cochrane Controlled Trials Register (CCTR), DARE, CINAHL and Psycho-Info) and reference lists of original studies and reviews were searched for all papers published up to 31 August 2011.

Study selection

Study designs included were either population-based intervention studies or a longitudinal study. Studies were included if the majority of the children studied were under 9 years, if they related to diet and if they focused on prevention rather than treatment in clinical settings.

Data extraction

Data included in the tables were characteristics of participants, aim, and key outcome results. Quality assessment of the selected studies was carried out to identify potential bias and an evidence ranking exercise carried out to prioritise areas for future public health interventions.

Data synthesis

Thirty-five studies (twenty-five intervention studies and ten longitudinal studies) were selected for the review. There was moderately strong evidence to support interventions on food promotion, large portion sizes and sugar-sweetened soft drinks.

Conclusions

Reducing food promotion to young children, increasing the availability of smaller portions and providing alternatives to sugar-sweetened soft drinks should be considered in obesity prevention programmes aimed at younger children. These environment-level interventions would support individual and family-level behaviour change.
BODY-SIZED WIDEBAND HIGH FIDELITY INVISIBILITY CLOAK
Authors: COHEN NATHAN
Published: December 2012

A human-sized microwave invisibility cloak has been realized. The invisibility cloak uses fractal metamaterials with two cloaking layers to achieve a high fidelity re-attainment of the intensity of an unobstructed direct path over a better than 50% bandwidth. A human subject was cloaked demonstrating a new milestone in diverted imaging capabilities: electrically large; high fidelity; and broad bandwidth. Transformational optics must now be considered less limiting in the guidance of practical applications.
Sex-dependent nutritional programming: fish oil intake during early pregnancy in rats reduces age-dependent insulin resistance in male, but not female, offspring
Authors: Sardinha Fatima L. C. , Fernandes Flavia S. , Tavares do Carmo Maria G. , Herrera Emilio
Published: December 2012

Prenatal and early postnatal nutritional status may predispose offspring to impaired glucose tolerance and changes in insulin sensitivity in adult life. The long-term consequences of changes in maternal dietary fatty acid composition were determined in rats. From day 1 until day 12 of pregnancy, rats were given isocaloric diets containing 9% nonvitamin fat based on soybean, olive, fish (FO), linseed, or palm oil. Thereafter, they were maintained on the standard diet; offspring were studied at different ages. Body weight at 4, 8, and 12 mo and lumbar adipose tissue and liver weights at 12 mo did not differ between females on the different diets, whereas in males the corresponding values were all lower in the offspring from the FO group compared with the other dietary groups. Plasma glucose concentrations (both basal and after an oral glucose load) did not change with sex or dietary group, but plasma insulin concentrations were lower in females than in males and, in males, were lowest in the FO group. Similar relations were found with both the homeostasis model assessment of insulin resistance and insulin sensitivity index. In conclusion, the intake of more n–3 fatty acids (FO diet) during early pregnancy reduced both fat accretion and age-related decline in insulin sensitivity in male offspring but not in females. It is proposed that the lower adiposity caused by the increased n–3 fatty acids during the intrauterine life was responsible of the lower insulin resistance in male offspring.
Functional integrity and modification of retinal dopaminergic neurons in the rd1 mutant mouse: roles of melanopsin and GABA
Authors: Atkinson Cameron L. , Feng Jie , Zhang Dao-Qi
Published: December 2012

The progressive loss of rod and cone photoreceptors in human subjects with retinitis pigmentosa causes a gradual decline in vision and can result in blindness. Current treatment strategies for the disease rely on the integrity of inner retinal neurons, such as amacrine cells, that are postsynaptic to photoreceptors. Previous work has demonstrated that a specialized subclass of retinal amacrine cell that synthesizes and releases the key neurotransmitter dopamine remains morphologically intact during the disease; however, the pathophysiological function of these neurons remains poorly understood. Here we examined spontaneous and light-evoked spike activity of genetically labeled dopamine neurons from the retinas of retinal degeneration 1 ( rd1) mice. Our results indicated that rd1 dopamine neurons remained functionally intact with preserved spontaneous spiking activity and light-evoked responses. The light responses were mediated exclusively by melanopsin phototransduction, not by surviving cones. Our data also suggested that dopamine neurons were altered during photoreceptor loss, as evidenced by less spontaneous bursting activity and increased light-evoked responses with age. Further evidence showed that these alterations were attributed to enhanced GABA/melanopsin signaling to dopamine neurons during disease progression. Taken together, our studies provide valuable information regarding the preservation and functional modification of the retinal dopamine neuronal system in rd1; this information should be considered when designing treatment strategies for retinitis pigmentosa.
Disseminated Intravascular Coagulation as a Possible Cause of Acute Coronary Stent Thrombosis: A Case Report and Literature Review
Authors: Amer Syed , Shafiq Ali , Qureshi Waqas , Muqeetadnan Mohammed , Hassan Syed
Published: December 2012

Disseminated intravascular coagulation (DIC), as a cause of acute coronary stent thrombosis, has not yet been reported to our knowledge. We report a case of 64-year-old male, who presented with non-ST-segment elevation myocardial infarction (NSTEMI). Coronary angiography revealed right coronary artery (RCA) stenosis and a drug eluting stent was deployed. Fifteen hours following the intervention, the patient developed an inferior wall ST elevation myocardial infarction. Repeat cardiac catheterization showed an acute in-stent thrombosis. Following thrombectomy, another stent was placed. The patient noted to have an acute drop in platelet count following the second intervention. Two hours following repeat intervention, the patient again developed chest pain and EKG showed recurrent ST-segment elevations in leads II, III, and aVF. Prior to repeat cardiac catheterization, the patient became unresponsive and developed cardiogenic shock. The patient was resuscitated and intubated, and repeat catheterization showed complete stent thrombosis. Intracoronary tissue plasminogen activator (tPA) was given. The platelet count further dropped. Additional studies confirmed the diagnosis of DIC. No further cardiac catheterization was done at this point. The patient then later had a cardiac arrest and unfortunately cardiopulmonary resuscitation could not revive him. Amongst the etiologies of acute stent thrombosis, DIC was deemed a possible cause.
Melanocyte Colonization and Pigmentation of Breast Carcinoma: Pathological and Clinical Aspects
Authors: Mele Marco , Laurberg Tinne , Engberg Damsgaard Tine , Funder Jonas , Jensen Vibeke
Published: December 2012

Introduction. Melanocyte colonization of breast carcinoma by nonneoplastic melanocytes of epidermal origin is a rare and serious condition first described in 1977. We report on the exceptional clinical and pathological features of this migration phenomenon in a 74-year-old patient.Discussion. The pathogenesis by which melanocyte migration takes place is not known, but a breached basement membrane is considered essential.Conclusion. Histological examination and additional staining of skin are essential to differentiate breast cancer melanosis from malignant melanoma.