1,241 research outputs found

    Association of DRG1 and DRG2 with Ribosomes from Pea, Arabidopsis and Yeast

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    DRGs are highly conserved GTP binding proteins.All eukaryotes examined contain DRG1 and DRG2 orthologs. The first experimental evidence for GTP binding by a plant DRG1 protein and by DRG2 from any organism is presented. DRG1 antibodies recognized a single ~43-kDa band in plant tissues, whereas DRG2 antibodies recognized ~45-,43-,and 30-kDa bands.An in vitro transcription and translation assay suggested that the 45-kDa band represents full-length DRG2 and that the smaller bands are specific proteolytic products. Homogenates from pea roots and root apices were used to produce fractions enriched in cytosolic and microsomal monosomes and polysomes. DRG1 and the 45- and 43-kDa DRG2 bands occurred in the cytosol and associated with cytosolic monosomes.I n contrast,the 30-kDa form of DRG2 was strongly enriched in polysome fractions.Thus,DRG1and the larger forms of DRG2 may be involved in translational initiation, and the 30-kDa form of DRG2 may be involved in translational elongation.DRG1 and the 45-and43-kDa forms of DRG2 can reassociate with ribosomes in vitro, a process that is partially inhibited by GTP-y-S Cells expressing FLAG-tagged ribosomal proteins from transgenic lines of Arabidopsis and yeast also demonstrated DRG-ribosome interactions

    Accuracy of PE rule-out strategies in pregnancy : secondary analysis of the DiPEP study prospective cohort

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    ObjectiveRecent studies suggest that combinations of clinical probability assessment (the YEARS algorithm or Geneva score) and D-dimer can safely rule out suspected pulmonary embolism (PE) in pregnant women. We performed a secondary analysis of the DiPEP (Diagnosis of Pulmonary Embolism in Pregnancy) study data to determine the diagnostic accuracy of these strategies.MethodsThe DiPEP study prospectively recruited and collected data and blood samples from pregnant/postpartum women with suspected PE across 11 hospitals and retrospectively collected data from pregnant/postpartum women with diagnosed PE across all UK hospitals (15 February 2015 to 31 August 2016). We selected prospectively recruited pregnant women who had definitive diagnostic imaging for this analysis. We used clinical data and D-dimer results to determine whether the rule out strategies would recommend further investigation. Two independent adjudicators used data from imaging reports, treatments and adverse events up to 30 days to determine the reference standard.ResultsPEs were diagnosed in 12/219 (5.5%) women. The YEARS/D-dimer strategy would have ruled out PE in 96/219 (43.8%) but this would have included 5 of the 12 with PEs. Sensitivity for PE was 58.3% (95% CI 28.6% to 83.5%) and specificity 44.0% (37.1% to 51.0%). The Geneva/D-dimer strategy would have ruled out PE in 46/219 (21.0%) but this would have included three of the 12 with PE. Sensitivity was 75.0% (95% CI 42.8% to 93.3%) and specificity 20.8% (95% CI 15.6% to 27.1%). Administration of anticoagulants prior to blood sampling may have reduced D-dimer sensitivity for small PE.ConclusionStrategies using clinical probability and D-dimer have limited diagnostic accuracy and do not accurately rule out all PE in pregnancy. It is uncertain whether PE missed by these strategies lead to clinically important consequences.</jats:sec

    Ovarian hyperstimulation syndrome: review and new classification criteria for reporting in clinical trials

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    STUDY QUESTION What is an objective approach that employs measurable and reproducible physiologic changes as the basis for the classification of ovarian hyperstimulation syndrome (OHSS) in order to facilitate more accurate reporting of incidence rates within and across clinical trials? SUMMARY ANSWER The OHSS flow diagram is an objective approach that will facilitate consistent capture, classification and reporting of OHSS within and across clinical trials. WHAT IS KNOWN ALREADY OHSS is a potentially life-threatening iatrogenic complication of the early luteal phase and/or early pregnancy after ovulation induction (OI) or ovarian stimulation (OS). The clinical picture of OHSS (the constellation of symptoms associated with each stage of the disease) is highly variable, hampering its appropriate classification in clinical trials. Although some degree of ovarian hyperstimulation is normal after stimulation, the point at which symptoms transition from those anticipated to those of a disease state is nebulous. STUDY DESIGN, SIZE, DURATION An OHSS working group, comprised of subject matter experts and clinical researchers who have significantly contributed to the field of fertility, was convened in April and November 2014. PARTICIPANTS/MATERIALS, SETTING, METHODS The OHSS working group was tasked with reaching a consensus on the definition and the classification of OHSS for reporting in clinical trials. The group engaged in targeted discussion regarding the scientific background of OHSS, the criteria proposed for the definition and the rationale for universal adoption. An agreement was reached after discussion with all members. MAIN RESULTS AND THE ROLE OF CHANCE One of the following conditions must be met prior to making the diagnosis of OHSS in the context of a clinical trial: (i) the subject has undergone OS (either controlled OS or OI) AND has received a trigger shot for final oocyte maturation (e.g. hCG, GnRH agonist [GnRHa] or kisspeptin) followed by either fresh transfer or segmentation (cryopreservation of embryos) or (ii) the subject has undergone OS or OI AND has a positive pregnancy test. All study patients who develop symptoms of OHSS should undergo a thorough examination. An OHSS flow diagram was designed to be implemented for all subjects with pelvic or abdominal complaints, such as lower abdominal discomfort or distention, nausea, vomiting and diarrhea, and/or for subjects suspected of having OHSS. The diagnosis of OHSS should be based on the flow diagram. LIMITATIONS, REASONS FOR CAUTION This classification system is primarily intended to address the needs of the clinical investigator undertaking clinical trials in the field of OS and may not be applicable for the use in clinical practice or with OHSS occurring under natural circumstances. WIDER IMPLICATIONS OF THE FINDINGS The proposed OHSS classification system will enable an accurate estimate of the incidence and severity of OHSS within and across clinical trials performed in women with infertility. STUDY FUNDING/COMPETING INTERESTS Financial support for the advisory group meetings was provided by Merck &#38; Co., Inc., Kenilworth, NJ, USA. P.H. reports unrestricted research grants from MSD, Merck and Ferring, and honoraria for lectures from MSD, Merck and IBSA. S.M.N. reports that he has received fees and grant support from the following companies (in alphabetic order): Beckman Coulter, Besins, EMD Serono, Ferring Pharmaceuticals, Finox, MSD and Roche Diagnostics over the previous 5 years. P.D., C.C.C., J.L.F., H.M.F., and P.L. report no relationships that present a potential conflict of interest. B.C.T. reports: grants and honorarium from Merck Serono; unrestricted research grants, travel grants and honorarium, and participation in a company-sponsored speaker's bureau from Merck Sharp &#38; Dohme; grants, travel grants, honoraria and advisory board membership from IBSA; travel grants from Ferring; and advisory board membership from Ovascience. L.B.S. reports current employment with Merck &#38; Co, Inc., Kenilworth, NJ, USA, and owns stock in the company. K.G. and B.J.S. report prior employment with Merck &#38; Co., Inc., Kenilworth, NJ, USA, and own stock in the company. All reported that competing interests are outside the submitted work. No other relationships or activities exist that could appear to have influenced the submitted work

    Local control of electric current driven shell etching of multiwalled carbon nanotubes

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    We report on a novel method for local control of shell engineering in multiwalled carbon nanotubes (MWNTs) using Joule-heating induced electric breakdown. By modulating the heat dissipation along a nanotube, we can confine its thinning and shell breakdown to occur within localized regions of peak temperatures, which are distributed over one-half of the NT length. The modulation is achieved by using suitably designed nanomachined heat sinks with different degrees of thermal coupling at different parts of a current-carrying nanotube. The location of electric breakdown occurs precisely at the regions of high temperatures predicted by the classical finite-element model of Joule heating in the MWNT. The experiments herein provide new insight into the electric breakdown mechanism and prove unambiguously that shell removal occurs due to thermal stress, underpinning the diffusive nature of MWNTs. The method demonstrated here has the potential to be a powerful tool in realizing MWNT bearings with complex architectures for use in integrated nanoelectromechanical systems (NEMS). In addition, the breakdown current and power in the nanotubes are significantly higher than those observed in nanotubes without heat removal via additional heat sinks. This indicates future avenues for enhancing the performance of MWNTs in electrical interconnect and nanoelectronic application

    The DiPEP (Diagnosis of PE in Pregnancy) biomarker study: An observational cohort study augmented with additional cases to determine the diagnostic utility of biomarkers for suspected venous thromboembolism during pregnancy and puerperium

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    This study aimed to estimate the diagnostic utility of biomarkers for suspected venous thromboembolism (VTE) in pregnancy and the puerperium. Research nurses/midwives collected blood samples from 310 pregnant/postpartum women with suspected pulmonary emboli (PE) and 18 with diagnosed deep vein thrombosis (DVT). VTE was diagnosed using imaging, treatment and adverse outcome data. Primary analysis was limited to women with conclusive imaging (36 with VTE, 247 without). The area under the curve (AUC) for each biomarker was: activated partial thromboplastin time 0·669 (95% confidence interval 0·570-0·768), B-type natriuretic peptide 0·549 (0·453-0·645), C-reactive protein 0·542 (0·445-0·639), Clauss fibrinogen 0·589 (0·476-0·701), D-Dimer (by enzyme-linked immunosorbent assay) 0·668 (0·561-0·776), near-patient D-Dimer 0·651 (0·545-0·758), mid-regional pro-atrial natriuretic peptide 0·524 (0·418-0·630), prothrombin fragment 1 + 2 0·562 (0·462-0·661), plasmin-antiplasmin complexes 0·639 (0·536-0·742), prothombin time 0·613 (0·508-0·718), thrombin generation lag time 0·702 (0·598-0·806), thrombin generation endogenous potential 0·559 (0·437-0·681), thrombin generation peak 0·596 (0·478-0·715), thrombin generation time to peak 0·655 (0·541-0·769), soluble tissue factor 0·531 (0·424-0·638) and serum troponin 0·597 (0·499-0·695). No diagnostically useful threshold for diagnosing or ruling out VTE was identified. In pregnancy and the puerperium, conventional and candidate biomarkers have no utility either for their negative or positive predictive value in the diagnosis of VTE

    Classical, novel and atypical isoforms of PKC stimulate ANF- and TRE/AP-1-regulated-promoter activity in ventricular cardiomyocytes

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    Cultured neonatal rat ventricular myocytes were co-transfected with expression plasmids encoding protein kinase C (PKC) isoforms from each of the PKC subfamilies (classical PKC-α, novel PKC-ε or atypical PKC-ξ) together with an atrial natriuretic factor (ANF) reporter plasmid. Each PKC had been rendered constitutively active by a single Ala→Glu mutation or a small deletion in the inhibitory pseudosubstrate site. cPKC-α, nPKC-ε or aPKC-ξ expression plasmids each stimulated ANF-promoter activity and expression of a reporter gene under the control of a 12-O-tetradecanoylphorbol 13-acetate-response element (TRE). Upregulation of the ANF promoter is characteristic of the hypertrophic response in the heart ventricle and a TRE is present in the ANF promoter. Thus all subfamilies of PKC may have the potential to contribute to hypertrophic response in cardiomyocytes

    Photoconductance Quantization in a Single-Photon Detector

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    We have made a single-photon detector that relies on photoconductive gain in a narrow electron channel in an AlGaAs/GaAs 2-dimensional electron gas. Given that the electron channel is 1-dimensional, the photo-induced conductance has plateaus at multiples of the quantum conductance 2e2^{2}/h. Super-imposed on these broad conductance plateaus are many sharp, small, conductance steps associated with single-photon absorption events that produce individual photo-carriers. This type of photoconductive detector could measure a single photon, while safely storing and protecting the spin degree of freedom of its photo-carrier. This function is valuable for a quantum repeater that would allow very long distance teleportation of quantum information.Comment: 4 pages, 4 figure

    Quantisation of Monopoles with Non-abelian Magnetic Charge

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    Magnetic monopoles in Yang-Mills-Higgs theory with a non-abelian unbroken gauge group are classified by holomorphic charges in addition to the topological charges familiar from the abelian case. As a result the moduli spaces of monopoles of given topological charge are stratified according to the holomorphic charges. Here the physical consequences of the stratification are explored in the case where the gauge group SU(3) is broken to U(2). The description due to A. Dancer of the moduli space of charge two monopoles is reviewed and interpreted physically in terms of non-abelian magnetic dipole moments. Semi-classical quantisation leads to dyonic states which are labelled by a magnetic charge and a representation of the subgroup of U(2) which leaves the magnetic charge invariant (centraliser subgroup). A key result of this paper is that these states fall into representations of the semi-direct product U(2) \semidir R^4. The combination rules (Clebsch-Gordan coefficients) of dyonic states can thus be deduced. Electric-magnetic duality properties of the theory are discussed in the light of our results, and supersymmetric dyonic BPS states which fill the SL(2,Z)-orbit of the basic massive W-bosons are found.Comment: 57 pages, harvmac, amssym, two eps figures, minor mistakes and typos corrected, references added; to appear in Nucl. Phys.

    Tunneling Time Distribution by means of Nelson's Quantum Mechanics and Wave-Particle Duality

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    We calculate a tunneling time distribution by means of Nelson's quantum mechanics and investigate its statistical properties. The relationship between the average and deviation of tunneling time suggests the exsistence of ``wave-particle duality'' in the tunneling phenomena.Comment: 14 pages including 11 figures, the text has been revise
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