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Chronic arsenic poisoning: A sinister cause of peripheral neuropathy in a young couple. J Postgrad Med 2024; 70:105-108. [PMID: 38629272 DOI: 10.4103/jpgm.jpgm_708_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 12/22/2023] [Indexed: 05/22/2024] Open
Abstract
ABSTRACT Arsenic compounds are colorless and odorless and toxicity can occur either acutely following ingestion of arsenicals with gastrointestinal disturbances or due to chronic exposure usually presenting with dermatologic lesions and peripheral neuropathy. We report a young couple who presented with signs and symptoms of painful sensorimotor peripheral neuropathy in a typical "stocking and glove" pattern. They had raised urinary arsenic levels with normal blood levels and thus, a diagnosis of chronic arsenic poisoning due to contaminated water intake was made after detecting elevated arsenic levels in their home water supply. Both patients underwent chelation therapy with dimercaprol for 14 days and reported subjective and objective improvement in symptoms with the reduction in urinary arsenic levels at the end of therapy.
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Measured proton electromagnetic structure deviates from theoretical predictions. Nature 2022; 611:265-270. [PMID: 36261531 DOI: 10.1038/s41586-022-05248-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/17/2022] [Indexed: 11/09/2022]
Abstract
The visible world is founded on the proton, the only composite building block of matter that is stable in nature. Consequently, understanding the formation of matter relies on explaining the dynamics and the properties of the proton's bound state. A fundamental property of the proton involves the response of the system to an external electromagnetic field. It is characterized by the electromagnetic polarizabilities1 that describe how easily the charge and magnetization distributions inside the system are distorted by the electromagnetic field. Moreover, the generalized polarizabilities2 map out the resulting deformation of the densities in a proton subject to an electromagnetic field. They disclose essential information about the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents. Of particular interest is a puzzle in the electric generalized polarizability of the proton that remains unresolved for two decades2. Here we report measurements of the proton's electromagnetic generalized polarizabilities at low four-momentum transfer squared. We show evidence of an anomaly to the behaviour of the proton's electric generalized polarizability that contradicts the predictions of nuclear theory and derive its signature in the spatial distribution of the induced polarization in the proton. The reported measurements suggest the presence of a new, not-yet-understood dynamical mechanism in the proton and present notable challenges to the nuclear theory.
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Precision Determination of the Neutral Weak Form Factor of ^{48}Ca. PHYSICAL REVIEW LETTERS 2022; 129:042501. [PMID: 35939025 DOI: 10.1103/physrevlett.129.042501] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/15/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
We report a precise measurement of the parity-violating (PV) asymmetry A_{PV} in the elastic scattering of longitudinally polarized electrons from ^{48}Ca. We measure A_{PV}=2668±106(stat)±40(syst) parts per billion, leading to an extraction of the neutral weak form factor F_{W}(q=0.8733 fm^{-1})=0.1304±0.0052(stat)±0.0020(syst) and the charge minus the weak form factor F_{ch}-F_{W}=0.0277±0.0055. The resulting neutron skin thickness R_{n}-R_{p}=0.121±0.026(exp)±0.024(model) fm is relatively thin yet consistent with many model calculations. The combined CREX and PREX results will have implications for future energy density functional calculations and on the density dependence of the symmetry energy of nuclear matter.
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Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study. Lancet Digit Health 2022; 4:e520-e531. [PMID: 35750401 DOI: 10.1016/s2589-7500(22)00069-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 01/07/2022] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications. METHODS We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC). FINDINGS In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]). INTERPRETATION In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required. FUNDING British Journal of Surgery Society.
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Novel, small molecule inhibitors of PD-1/PD-L1 pathway. J Clin Oncol 2022. [DOI: 10.1200/jco.2022.40.16_suppl.2597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
2597 Background: Programmed Cell Death 1 (PD-1) protein plays a key role in inhibiting immune responses and enhancing self-tolerance via modulation of T-cell activity, inducing T-cell apoptosis and inhibiting apoptosis of regulatory T cells. PD-L1 also plays an important role in various malignancies where it can attenuate the host immune response to tumor cells thereby favouring tumor progression and metastasis. High expression of PD-L1 in glioblastoma tumor tissues is associated with poor survival of patients, and PD-L1 may act as a prognostic predictor and an effective therapeutic target for glioblastoma. A number of monoclonal antibodies targeting PD-1/PD-L1 have approved for various malignancies. Still, efficacy of these antibodies in glioblastoma and brain metastasis continues to be moderate potentially owing to lack of or poor brain penetrance of these agents. Therefore, there is still a need for potent, selective small molecule PD-1/PD-L1 inhibitors with enhanced brain penetration in the treatment of such cancers. Methods: Rational design approaches were used to design novel small molecule PD-1/PD-L1 pathway inhibitors; potency of these inhibitors was assessed in an in-vitro TR-FRET assay. Checkpoints signalling reporter assays as well cell based PD-L1 dimerization assays were used to assess the mechanistic and functional effects. In vivo efficacy was assessed in orthotopic GBM as well as in syngeneic and humanized subcutaneous tumor models in mice. Results: Our lead PD-L1 inhibitor JBI-2174 showed strong in vitro IC50 of ̃1 nM in TR-FRET assay that measures interaction between hPD-1 and hPD-L1 and a picomolar IC50 against monkey PD-L1. In selectivity assays for immunooncology targets, JBI-2174 was highly selective for PD-L1. JBI-2174 also inhibited PD-L1/PD-1 mediated signalling essential for T-cell modulation. JBI-2174 induced dimerization of PD-L1 as observed by size exclusion chromatography, which was confirmed by co-crystal structure and recapitulated in cell based dimerization assay. Elucidation of the co-crystal structure, clearly demonstrated that JBI-2174 clearly interacts with multiple amino acids on PD-L1 that are critical for PD-1 binding. JBI-2174 showed excellent oral bioavailability across pre-clinical species and sustained brain exposure. In the in vivo efficacy studies, JBI-2174 showed comparable efficacy to the anti-PD-L1 antibody or Atezolizumab in syngeneic (4T1, CT-26) and in partially humanized models (MC-38/hPD-L1). Further, oral administration of JBI-2174 resulted in statistically significant increase in survival (Day 27 in control vs day 38 in treated, p < 0.05) in a mouse glioma orthotopic model. Conclusions: The oral bioavailability and brain exposure of this molecule will make it attractive for cancers with unmet medical needs such as GBM and brain metastasis. IND enabling studies are being initiated for this compound.
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OC-0606 Multi-institutional outcomes of Gleason grade group 5 prostate cancers treated with EBRT and ADT. Radiother Oncol 2022. [DOI: 10.1016/s0167-8140(22)02628-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Determination of the ^{27}Al Neutron Distribution Radius from a Parity-Violating Electron Scattering Measurement. PHYSICAL REVIEW LETTERS 2022; 128:132501. [PMID: 35426696 DOI: 10.1103/physrevlett.128.132501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
We report the first measurement of the parity-violating elastic electron scattering asymmetry on ^{27}Al. The ^{27}Al elastic asymmetry is A_{PV}=2.16±0.11(stat)±0.16(syst) ppm, and was measured at ⟨Q^{2}⟩=0.02357±0.00010 GeV^{2}, ⟨θ_{lab}⟩=7.61°±0.02°, and ⟨E_{lab}⟩=1.157 GeV with the Q_{weak} apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the ^{27}Al neutron radius R_{n}=2.89±0.12 fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R_{n}-R_{p}=-0.04±0.12 fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves as a successful benchmark for electroweak determinations of neutron radii on heavier nuclei. A tree-level approach was used to extract the ^{27}Al weak radius R_{w}=3.00±0.15 fm, and the weak skin thickness R_{wk}-R_{ch}=-0.04±0.15 fm. The weak form factor at this Q^{2} is F_{wk}=0.39±0.04.
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Accurate Determination of the Neutron Skin Thickness of ^{208}Pb through Parity-Violation in Electron Scattering. PHYSICAL REVIEW LETTERS 2021; 126:172502. [PMID: 33988387 DOI: 10.1103/physrevlett.126.172502] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
We report a precision measurement of the parity-violating asymmetry A_{PV} in the elastic scattering of longitudinally polarized electrons from ^{208}Pb. We measure A_{PV}=550±16(stat)±8(syst) parts per billion, leading to an extraction of the neutral weak form factor F_{W}(Q^{2}=0.00616 GeV^{2})=0.368±0.013. Combined with our previous measurement, the extracted neutron skin thickness is R_{n}-R_{p}=0.283±0.071 fm. The result also yields the first significant direct measurement of the interior weak density of ^{208}Pb: ρ_{W}^{0}=-0.0796±0.0036(exp)±0.0013(theo) fm^{-3} leading to the interior baryon density ρ_{b}^{0}=0.1480±0.0036(exp)±0.0013(theo) fm^{-3}. The measurement accurately constrains the density dependence of the symmetry energy of nuclear matter near saturation density, with implications for the size and composition of neutron stars.
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Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering. PHYSICAL REVIEW LETTERS 2020; 125:112502. [PMID: 32976004 DOI: 10.1103/physrevlett.125.112502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/07/2020] [Accepted: 08/11/2020] [Indexed: 06/11/2023]
Abstract
A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θ_{lab}=7.9° and a mean energy of 1.149 GeV. The asymmetry result is B_{n}=-5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θ_{lab}→0) where they should be most reliable.
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Role of age in a MRI-based active surveillance cohort: Association with clinical and radiological progression. EUR UROL SUPPL 2020. [DOI: 10.1016/s2666-1683(20)33636-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Scaffold Morphing To Identify Novel DprE1 Inhibitors with Antimycobacterial Activity. ACS Med Chem Lett 2019; 10:1480-1485. [PMID: 31620237 DOI: 10.1021/acsmedchemlett.9b00343] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/23/2019] [Indexed: 11/29/2022] Open
Abstract
We report a novel benzimidazole (BI) based DprE1 inhibitor that resulted from scaffold morphing of a 1,4-azaindole series. The clinical progression of the 1,4-azaindole series from our previous work validates the potential of exploring newer chemical entities with antimycobacterial activity driven via a noncovalent inhibition of the decaprenylphosphoryl-β-d-ribose-2'-epimerase (DprE1). The representative compounds from the new scaffold reported in this study exhibited an improved solubility and higher free plasma fraction, while retaining potent DprE1 inhibition and antimycobacterial activity. A representative compound from the benzimidazole series demonstrated good efficacy in a murine model of tuberculosis. Furthermore, molecular modeling of the BI scaffold suggests plausible modes of binding in the active site of DprE1 enzyme from Mycobacterium tuberculosis that can be used for further exploration of the series.
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Azimuthal Anisotropy of Heavy-Flavor Decay Electrons in p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV. PHYSICAL REVIEW LETTERS 2019; 122:072301. [PMID: 30848618 DOI: 10.1103/physrevlett.122.072301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 10/16/2018] [Indexed: 06/09/2023]
Abstract
Angular correlations between heavy-flavor decay electrons and charged particles at midrapidity (|η|<0.8) are measured in p-Pb collisions at sqrt[s_{NN}]=5.02 TeV. The analysis is carried out for the 0%-20% (high) and 60%-100% (low) multiplicity ranges. The jet contribution in the correlation distribution from high-multiplicity events is removed by subtracting the distribution from low-multiplicity events. An azimuthal modulation remains after removing the jet contribution, similar to previous observations in two-particle angular correlation measurements for light-flavor hadrons. A Fourier decomposition of the modulation results in a positive second-order coefficient (v_{2}) for heavy-flavor decay electrons in the transverse momentum interval 1.5<p_{T}<4 GeV/c in high-multiplicity events, with a significance larger than 5σ. The results are compared with those of charged particles at midrapidity and those of inclusive muons at forward rapidity. The v_{2} measurement of open heavy-flavor particles at midrapidity in small collision systems could provide crucial information to help interpret the anisotropies observed in such systems.
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Revealing Color Forces with Transverse Polarized Electron Scattering. PHYSICAL REVIEW LETTERS 2019; 122:022002. [PMID: 30720291 DOI: 10.1103/physrevlett.122.022002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 10/18/2018] [Indexed: 06/09/2023]
Abstract
The Spin Asymmetries of the Nucleon Experiment measured two double spin asymmetries using a polarized proton target and polarized electron beam at two beam energies, 4.7 and 5.9 GeV. A large-acceptance open-configuration detector package identified scattered electrons at 40° and covered a wide range in Bjorken x (0.3<x<0.8). Proportional to an average color Lorentz force, the twist-3 matrix element, d[over ˜]_{2}^{p}, was extracted from the measured asymmetries at Q^{2} values ranging from 2.0 to 6.0 GeV^{2}. The data display the opposite sign compared to most quark models, including the lattice QCD result, and an unexpected scale dependence. Furthermore, when combined with the neutron data in the same Q^{2} range the results suggest a flavor independent average color Lorentz force.
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14
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Comparison of Inducible and Spontaneous Ventricular Tachycardia in Defibrillator Recipients Following Myocardial Infarction. Heart Lung Circ 2019. [DOI: 10.1016/j.hlc.2019.06.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Trends in Cardiovascular Risk Factors in STEMI Patients at an Urban Centre. Heart Lung Circ 2019. [DOI: 10.1016/j.hlc.2019.06.566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Optically induced transient enhancement of a structural order parameter. EPJ WEB OF CONFERENCES 2019. [DOI: 10.1051/epjconf/201920507001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We photoexcite SrTiO3 and EuTiO3 in their purely soft-mode-driven structurally distorted phase and trace the structural order parameter via ultra-short x-rays. We observe a rapid decay for SrTiO3 and an intriguing transient enhancement for EuTiO3.
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Synthetic analogues of the parasitic worm product ES-62 reduce disease development in in vivo models of lung fibrosis. Acta Trop 2018; 185:212-218. [PMID: 29802846 DOI: 10.1016/j.actatropica.2018.05.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 05/22/2018] [Indexed: 12/21/2022]
Abstract
Parasitic worms are receiving much attention as a potential new therapeutic approach to treating autoimmune and allergic conditions but concerns remain regarding their safety. As an alternative strategy, we have focused on the use of defined parasitic worm products and recently taken this one step further by designing drug-like small molecule analogues of one such product, ES-62, which is anti-inflammatory by virtue of covalently attached phosphorylcholine moieties. Previously, we have shown that ES-62 mimics are efficacious in protecting against disease in mouse models of rheumatoid arthritis, systemic lupus erythematosus and skin and lung allergy. Given the potential role of chronic inflammation in fibrosis, in the present study we have focused our attention on lung fibrosis, a debilitating condition for which there is no cure and which in spite of treatment slowly gets worse over time. Two mouse models of fibrosis - bleomycin-induced and LPS-induced - in which roles for inflammation have been implicated were adopted. Four ES-62 analogues were tested - 11a and 12b, previously shown to be active in mouse models of allergic and autoimmune disease and 16b and AIK-29/62 both of which are structurally related to 11a. All four compounds were found to significantly reduce disease development in both fibrosis models, as shown by histopathological analysis of lung tissue, indicating their potential as treatments for this condition.
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D-Meson Azimuthal Anisotropy in Midcentral Pb-Pb Collisions at sqrt[s]_{NN}=5.02 TeV. PHYSICAL REVIEW LETTERS 2018; 120:102301. [PMID: 29570314 DOI: 10.1103/physrevlett.120.102301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 11/16/2017] [Indexed: 06/08/2023]
Abstract
The azimuthal anisotropy coefficient v_{2} of prompt D^{0}, D^{+}, D^{*+}, and D_{s}^{+} mesons was measured in midcentral (30%-50% centrality class) Pb-Pb collisions at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02 TeV, with the ALICE detector at the LHC. The D mesons were reconstructed via their hadronic decays at midrapidity, |y|<0.8, in the transverse momentum interval 1<p_{T}<24 GeV/c. The measured D-meson v_{2} has similar values as that of charged pions. The D_{s}^{+} v_{2}, measured for the first time, is found to be compatible with that of nonstrange D mesons. The measurements are compared with theoretical calculations of charm-quark transport in a hydrodynamically expanding medium and have the potential to constrain medium parameters.
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Radiation-related soft tissue sarcoma in a veterinary technician. Diagn Interv Imaging 2018; 99:181-182. [PMID: 29398573 DOI: 10.1016/j.diii.2017.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 11/27/2022]
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J/ψ Elliptic Flow in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV. PHYSICAL REVIEW LETTERS 2017; 119:242301. [PMID: 29286736 DOI: 10.1103/physrevlett.119.242301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Indexed: 06/07/2023]
Abstract
We report a precise measurement of the J/ψ elliptic flow in Pb-Pb collisions at sqrt[s_{NN}]=5.02 TeV with the ALICE detector at the LHC. The J/ψ mesons are reconstructed at midrapidity (|y|<0.9) in the dielectron decay channel and at forward rapidity (2.5<y<4.0) in the dimuon channel, both down to zero transverse momentum. At forward rapidity, the elliptic flow v_{2} of the J/ψ is studied as a function of the transverse momentum and centrality. A positive v_{2} is observed in the transverse momentum range 2<p_{T}<8 GeV/c in the three centrality classes studied and confirms with higher statistics our earlier results at sqrt[s_{NN}]=2.76 TeV in semicentral collisions. At midrapidity, the J/ψ v_{2} is investigated as a function of the transverse momentum in semicentral collisions and found to be in agreement with the measurements at forward rapidity. These results are compared to transport model calculations. The comparison supports the idea that at low p_{T} the elliptic flow of the J/ψ originates from the thermalization of charm quarks in the deconfined medium but suggests that additional mechanisms might be missing in the models.
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Assessing response to immunotherapy in patients with non-small cell lung cancer using circulating tumor DNA. Ann Oncol 2017. [DOI: 10.1093/annonc/mdx380.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Production of [Formula: see text] and [Formula: see text] mesons up to high transverse momentum in pp collisions at 2.76 TeV. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS 2017; 77:339. [PMID: 28943788 PMCID: PMC5586361 DOI: 10.1140/epjc/s10052-017-4890-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/05/2017] [Indexed: 06/07/2023]
Abstract
The invariant differential cross sections for inclusive [Formula: see text] and [Formula: see text] mesons at midrapidity were measured in pp collisions at [Formula: see text] TeV for transverse momenta [Formula: see text] GeV/c and [Formula: see text] GeV/c, respectively, using the ALICE detector. This large range in [Formula: see text] was achieved by combining various analysis techniques and different triggers involving the electromagnetic calorimeter (EMCal). In particular, a new single-cluster, shower-shape based method was developed for the identification of high-[Formula: see text] neutral pions, which exploits that the showers originating from their decay photons overlap in the EMCal. Above 4 GeV/[Formula: see text], the measured cross sections are found to exhibit a similar power-law behavior with an exponent of about 6.3. Next-to-leading-order perturbative QCD calculations differ from the measured cross sections by about 30% for the [Formula: see text], and between 30-50% for the [Formula: see text] meson, while generator-level simulations with PYTHIA 8.2 describe the data to better than 10-30%, except at [Formula: see text] GeV/[Formula: see text]. The new data can therefore be used to further improve the theoretical description of [Formula: see text] and [Formula: see text] meson production.
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Discovery of Imidazo[1,2-a]pyridine Ethers and Squaramides as Selective and Potent Inhibitors of Mycobacterial Adenosine Triphosphate (ATP) Synthesis. J Med Chem 2017; 60:1379-1399. [PMID: 28075132 DOI: 10.1021/acs.jmedchem.6b01358] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The approval of bedaquiline to treat tuberculosis has validated adenosine triphosphate (ATP) synthase as an attractive target to kill Mycobacterium tuberculosis (Mtb). Herein, we report the discovery of two diverse lead series imidazo[1,2-a]pyridine ethers (IPE) and squaramides (SQA) as inhibitors of mycobacterial ATP synthesis. Through medicinal chemistry exploration, we established a robust structure-activity relationship of these two scaffolds, resulting in nanomolar potencies in an ATP synthesis inhibition assay. A biochemical deconvolution cascade suggested cytochrome c oxidase as the potential target of IPE class of molecules, whereas characterization of spontaneous resistant mutants of SQAs unambiguously identified ATP synthase as its molecular target. Absence of cross resistance against bedaquiline resistant mutants suggested a different binding site for SQAs on ATP synthase. Furthermore, SQAs were found to be noncytotoxic and demonstrated efficacy in a mouse model of tuberculosis infection.
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Normal BMI is a Significant Independent Predictor of Spontaneously Occurring Ventricular Arrhythmias and Mortality in Patients with Myocardial Infarction, Left Ventricular Dysfunction and ICD Implantation. Heart Lung Circ 2017. [DOI: 10.1016/j.hlc.2017.06.327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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ST-Elevation Myocardial Infarction in an Australian Migrant Population: a Registry Based Study of Patient Treatment and Outcomes. Heart Lung Circ 2017. [DOI: 10.1016/j.hlc.2017.06.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Normal BMI Is a Significant Independent Predictor of Inducible Ventricular Tachycardia and Mortality in Patients with Myocardial Infarction and Left Ventricular Dysfunction. Heart Lung Circ 2017. [DOI: 10.1016/j.hlc.2017.06.290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Does the expectation of pain with intrauterine device (IUD) insertion differ between those who initiate IUD and those who do not? A survey of adolescents and young adult women. Contraception 2016. [DOI: 10.1016/j.contraception.2016.07.097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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29
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Scaffold morphing leading to evolution of 2,4-diaminoquinolines and aminopyrazolopyrimidines as inhibitors of the ATP synthesis pathway. MEDCHEMCOMM 2016. [DOI: 10.1039/c5md00589b] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
2,4-Diaminoquinazolines, 2,4-diaminoquinolines and aminopyrazolopyrimidines, inhibitors of mycobacterial ATP synthesis, are novel lead molecules towards discovery and development of new anti-tubercular agents.
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30
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Whole cell screen based identification of spiropiperidines with potent antitubercular properties. Bioorg Med Chem Lett 2015; 25:3234-45. [DOI: 10.1016/j.bmcl.2015.05.087] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 05/23/2015] [Accepted: 05/26/2015] [Indexed: 11/24/2022]
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31
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2-Phenylindole and Arylsulphonamide: Novel Scaffolds Bactericidal against Mycobacterium tuberculosis. ACS Med Chem Lett 2014; 5:1005-9. [PMID: 25221657 DOI: 10.1021/ml5001933] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/11/2014] [Indexed: 11/29/2022] Open
Abstract
A cellular activity-based screen on Mycobacterium tuberculosis (Mtb) H37Rv using a focused library from the AstraZeneca corporate collection led to the identification of 2-phenylindoles and arylsulphonamides, novel antimycobacterial scaffolds. Both the series were bactericidal in vitro and in an intracellular macrophage infection model, active against drug sensitive and drug resistant Mtb clinical isolates, and specific to mycobacteria. The scaffolds showed promising structure-activity relationships; compounds with submicromolar cellular potency were identified during the hit to lead exploration. Furthermore, compounds from both scaffolds were tested for inhibition of known target enzymes or pathways of antimycobacterial drugs including InhA, RNA polymerase, DprE1, topoisomerases, protein synthesis, and oxidative-phosphorylation. Compounds did not inhibit any of the targets suggesting the potential of a possible novel mode of action(s). Hence, both scaffolds provide the opportunity to be developed further as leads and tool compounds to uncover novel mechanisms for tuberculosis drug discovery.
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Diarylthiazole: An Antimycobacterial Scaffold Potentially Targeting PrrB-PrrA Two-Component System. J Med Chem 2014; 57:6572-82. [DOI: 10.1021/jm500833f] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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33
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Precision measurement of the neutron twist-3 matrix element d(2)(n): probing color forces. PHYSICAL REVIEW LETTERS 2014; 113:022002. [PMID: 25062166 DOI: 10.1103/physrevlett.113.022002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Indexed: 06/03/2023]
Abstract
Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25≤x≤0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized (3)He target. In this dedicated experiment, the spin structure function g(2)((3)He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at ⟨Q(2)⟩ of 3.21 and 4.32 GeV(2)/c(2), with an absolute precision of about 10(-5). Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ⟨Q(2)⟩=5 GeV(2)/c(2). Combining d(2)(n) and a newly extracted twist-4 matrix element f(2)(n), the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30 MeV/fm in magnitude.
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34
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Measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the reaction (3)He(↑)(e,e')X. PHYSICAL REVIEW LETTERS 2014; 113:022502. [PMID: 25062169 DOI: 10.1103/physrevlett.113.022502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Indexed: 06/03/2023]
Abstract
We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3)He(↑)(e,e')X on a polarized (3)He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be nonzero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7<W<2.9 GeV, 1.0<Q(2)<4.0 GeV(2) and 0.16<x<0.65. Neutron asymmetries were extracted using the effective nucleon polarization and measured proton-to-(3)He cross-section ratios. The measured neutron asymmetries are negative with an average value of (-1.09±0.38)×10(-2) for invariant mass W>2 GeV, which is nonzero at the 2.89σ level. Our measured asymmetry agrees both in sign and magnitude with a two-photon-exchange model prediction that uses input from the Sivers transverse momentum distribution obtained from semi-inclusive deep-inelastic scattering.
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35
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4-Aminoquinolone Piperidine Amides: Noncovalent Inhibitors of DprE1 with Long Residence Time and Potent Antimycobacterial Activity. J Med Chem 2014; 57:5419-34. [DOI: 10.1021/jm5005978] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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36
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Discovery of pyrazolopyridones as a novel class of noncovalent DprE1 inhibitor with potent anti-mycobacterial activity. J Med Chem 2014; 57:4761-71. [PMID: 24818517 DOI: 10.1021/jm5002937] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel pyrazolopyridone class of inhibitors was identified from whole cell screening against Mycobacterium tuberculosis (Mtb). The series exhibits excellent bactericidality in vitro, resulting in a 4 log reduction in colony forming units following compound exposure. The significant modulation of minimum inhibitory concentration (MIC) against a Mtb strain overexpressing the Rv3790 gene suggested the target of pyrazolopyridones to be decaprenylphosphoryl-β-D-ribose-2'-epimerase (DprE1). Genetic mapping of resistance mutation coupled with potent enzyme inhibition activity confirmed the molecular target. Detailed biochemical characterization revealed the series to be a noncovalent inhibitor of DprE1. Docking studies at the active site suggest that the series can be further diversified to improve the physicochemical properties without compromising the antimycobacterial activity. The pyrazolopyridone class of inhibitors offers an attractive non-nitro lead series targeting the essential and vulnerable DprE1 enzyme for the discovery of novel antimycobacterial agents to treat both drug susceptible and drug resistant strains of Mtb.
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38
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What is the optimal left ventricular ejection fraction cut-off for risk stratification for primary prevention of sudden cardiac death early after myocardial infarction? Europace 2014; 16:1315-21. [DOI: 10.1093/europace/euu026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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39
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Azaindoles: noncovalent DprE1 inhibitors from scaffold morphing efforts, kill Mycobacterium tuberculosis and are efficacious in vivo. J Med Chem 2013; 56:9701-8. [PMID: 24215368 DOI: 10.1021/jm401382v] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report 1,4-azaindoles as a new inhibitor class that kills Mycobacterium tuberculosis in vitro and demonstrates efficacy in mouse tuberculosis models. The series emerged from scaffold morphing efforts and was demonstrated to noncovalently inhibit decaprenylphosphoryl-β-D-ribose2'-epimerase (DprE1). With "drug-like" properties and no expectation of pre-existing resistance in the clinic, this chemical class has the potential to be developed as a therapy for drug-sensitive and drug-resistant tuberculosis.
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Coronary artery reperfusion for ST elevation myocardial infarction is associated with shorter cycle length ventricular tachycardia and fewer spontaneous arrhythmias. Europace 2013; 16:1053-60. [DOI: 10.1093/europace/eut307] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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41
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First determination of the weak charge of the proton. PHYSICAL REVIEW LETTERS 2013; 111:141803. [PMID: 24152148 DOI: 10.1103/physrevlett.111.141803] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Indexed: 06/02/2023]
Abstract
The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 μA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run, constituting approximately 4% of the data collected in the experiment, are reported here. From these initial results, the measured asymmetry is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which is the smallest and most precise asymmetry ever measured in ep scattering. The small Q(2) of this experiment has made possible the first determination of the weak charge of the proton Q(W)(p) by incorporating earlier parity-violating electron scattering (PVES) data at higher Q(2) to constrain hadronic corrections. The value of Q(W)(p) obtained in this way is Q(W)(p)(PVES)=0.064±0.012, which is in good agreement with the standard model prediction of Q(W)(p)(SM)=0.0710±0.0007. When this result is further combined with the Cs atomic parity violation (APV) measurement, significant constraints on the weak charges of the up and down quarks can also be extracted. That PVES+APV analysis reveals the neutron's weak charge to be Q(W)(n)(PVES+APV)=-0.975±0.010.
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42
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Measurements of parity-violating asymmetries in electron-deuteron scattering in the nucleon resonance region. PHYSICAL REVIEW LETTERS 2013; 111:082501. [PMID: 24016222 DOI: 10.1103/physrevlett.111.082501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Indexed: 06/02/2023]
Abstract
We report on parity-violating asymmetries in the nucleon resonance region measured using inclusive inelastic scattering of 5-6 GeV longitudinally polarized electrons off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the Δ(1232). They provide a verification of quark-hadron duality-the equivalence of the quark- and hadron-based pictures of the nucleon-at the (10-15)% level in this electroweak observable, which is dominated by contributions from the nucleon electroweak γZ interference structure functions. In addition, the results provide constraints on nucleon resonance models relevant for calculating background corrections to elastic parity-violating electron scattering measurements.
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LC-MS based assay to measure intracellular compound levels in Mycobacterium smegmatis: linking compound levels to cellular potency. J Microbiol Methods 2013; 94:152-158. [PMID: 23747411 DOI: 10.1016/j.mimet.2013.05.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/07/2013] [Accepted: 05/14/2013] [Indexed: 11/18/2022]
Abstract
Dihydrofolate reductase (DHFR) plays a central role in maintaining cellular pool of tetrahydrofolic acid, a cofactor necessary for DNA, RNA and protein synthesis. The clinical validation of DHFR as antibacterial target was established by the success of trimethoprim (TMP). DHFR is also an attractive target for identifying anti-tuberculosis molecules however, due to observed weak cellular potency, no DHFR inhibitors have been developed as drugs so far. TMP and its analogs have poor cellular potency on Mycobacterium tuberculosis and Mycobacterium smegmatis cells. We found a mutant strain of M. smegmatis, mc²155 to be sensitive to TMP whereas wild type strain was not inhibited by TMP. We utilized this system to probe if poor or lack of activity of TMP is a consequence of poor intracellular compound levels. An LC-MS based method was developed for measuring TMP and rifampicin (RIF) in M. smegmatis. Using the assay, equivalent RIF levels were observed in both strains however, TMP was detected only in mc²155 cells, hence proving a positive correlation between potency and compound levels. To the best of our knowledge this is the first time LC-MS method has been used to measure compound levels in mycobacterial cells. We propose it to be a valuable tool to understand the lack of potency or resistance mechanisms in antimycobacterial drug development.
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Induction of ventricular tachycardia with the fourth extrastimulus and its relationship to risk of arrhythmic events in patients with post-myocardial infarct left ventricular dysfunction. Europace 2012; 14:1771-7. [DOI: 10.1093/europace/eus199] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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46
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New precision limit on the strange vector form factors of the proton. PHYSICAL REVIEW LETTERS 2012; 108:102001. [PMID: 22468841 DOI: 10.1103/physrevlett.108.102001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Indexed: 05/31/2023]
Abstract
The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624 GeV2 and beam energy E(b) = 3.48 GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.
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47
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Beam-target double-spin asymmetry A{LT} in charged pion production from deep inelastic scattering on a transversely polarized {3}He target at 1.4<Q{2}<2.7 GeV{2}. PHYSICAL REVIEW LETTERS 2012; 108:052001. [PMID: 22400926 DOI: 10.1103/physrevlett.108.052001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Indexed: 05/31/2023]
Abstract
We report the first measurement of the double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused on the valence quark region, 0.16<x<0.35 with 1.4<Q{2}<2.7 GeV{2}. The corresponding neutron A{LT} asymmetries were extracted from the measured {3}He asymmetries and proton over {3}He cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function g{1T}{q} and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for π{-} production on {3}He and the neutron, while our π{+} asymmetries are consistent with zero.
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48
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Single spin asymmetries in charged pion production from semi-inclusive deep inelastic scattering on a transversely polarized 3He Target at Q2 = 1.4-2.7 GeV2. PHYSICAL REVIEW LETTERS 2011; 107:072003. [PMID: 21902386 DOI: 10.1103/physrevlett.107.072003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Indexed: 05/31/2023]
Abstract
We report the first measurement of target single spin asymmetries in the semi-inclusive (3)He(e,e'π(±))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16 < x < 0.35 with 1.4 < Q(2) < 2.7 GeV(2). The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π(±) Collins moments for (3)He are consistent with zero, except for the π(+) moment at x = 0.35, which deviates from zero by 2.3σ. While the π(-) Sivers moments are consistent with zero, the π(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to (3)He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.
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Search for effects beyond the born approximation in polarization transfer observables in e(over→)p elastic scattering. PHYSICAL REVIEW LETTERS 2011; 106:132501. [PMID: 21520982 DOI: 10.1103/physrevlett.106.132501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Indexed: 05/30/2023]
Abstract
Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, G(E)/G(M), obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic H(e[over →],e(')p[over →]) reaction for three different beam energies at a Q(2)=2.5 GeV(2), spanning a wide range of the kinematic parameter ε. The ratio R, which equals μ(p)G(E)/G(M) in the Born approximation, is found to be independent of ε at the 1.5% level. The ε dependence of the longitudinal polarization transfer component P(ℓ) shows an enhancement of (2.3±0.6)% relative to the Born approximation at large ε.
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50
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Primary Prevention of Sudden Cardiac Death in Ischaemic Cardiomyopathy: The Role of the Fourth Extrastimulus at Electrophysiologic Study. Heart Lung Circ 2011. [DOI: 10.1016/j.hlc.2011.05.523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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