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Dehghan A, Haseli S, Keshavarz P, Ahmadi M, Dehghani P. Be Aware of Aberrant Right Subclavian Artery Origin Before Aortic Coarctation Stenting: A Case Report Study. Vasc Endovascular Surg 2019; 53:609-612. [PMID: 31309863 DOI: 10.1177/1538574419858827] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The subclavian steal syndrome (SSS), also called subclavian steal steno-occlusive disease, is defined as reversal of the vertebral artery flow secondary to significant hemodynamically ipsilateral occlusion or stenosis of the proximal subclavian artery. It is usually seen secondary to atherosclerosis and aberrant right subclavian artery (ARSA), resulting in SSS which is even less common. Aberrant right subclavian artery is a kind of vascular anomaly associated with coarctation of the aorta (CoA). It usually originates from the descending aorta distal to the site of CoA. Here, we present a young man who was a case of ARSA and CoA. He developed SSS after transcatheter aortic stenting secondary to unusual origin of ARSA from the site of CoA. Awareness of this rare anomaly helps to overcome this complication in patients undergoing interventional stenting for CoA and ARSA with anomalous origin.
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Ahmadi M, Timoshenko J, Behafarid F, Roldan Cuenya B. Tuning the Structure of Pt Nanoparticles through Support Interactions: An in Situ Polarized X-ray Absorption Study Coupled with Atomistic Simulations. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2019; 123:10666-10676. [PMID: 31049123 PMCID: PMC6487391 DOI: 10.1021/acs.jpcc.9b00945] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/25/2019] [Indexed: 05/31/2023]
Abstract
Interactions of nanoparticles (NPs) with their environment may have a pronounced effect on their structure and shape as well as on their functionality in applications such as catalysis. It is therefore crucial to disentangle the particle-adsorbate and particle-support interaction effects on the particle shape, its local structure, atomic dynamics, and its possible anisotropies. In order to gain insight into the support effect, we carried out an X-ray absorption fine-structure spectroscopy (XAFS) investigation of adsorbate- and ligand-free size-selected Pt NPs deposited on two different supports in ultrahigh vacuum. Polarization-dependent XAFS measurements, neural network-based analysis of X-ray absorption near-edge structure data, and reverse Monte Carlo (RMC) simulations of extended X-ray absorption fine structure (EXAFS) were used to resolve the 3D shape of the NPs and details of their local structure. A synergetic combination of advanced in situ XAFS analysis with atomic force microscopy and scanning tunneling microscopy (STM) imaging provides uniquely detailed information about the particle-support interactions and the NP/support buried interface, not accessible to any experimental technique, when considered alone. In particular, our combined approach reveals differences in the structure of Pt NPs deposited on TiO2(110) and SiO2/Si(111). Pt NPs on SiO2 assume a spherical-like 3D shape and weakly interact with the support. In contrast, the effective shape of analogously synthesized Pt NPs on TiO2(110) after annealing at 600 °C is found to be a truncated octahedron with (100) top and interfacial facets that are encapsulated by the TiO2 support. Modeling disorder effects in these NPs using an RMC approach reveals differences in bond-length distributions for NPs on different supports and allows us to analyze their anisotropy, which may be crucial for the interpretation of support-dependent atomic dynamics and can have an impact on the understanding of the catalytic properties of these NPs.
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Dumas L, Piliero N, Montemagno C, Ahmadi M, Bacot S, Pascal P, Riou L, Fagret D, Barone-Rochette G, Broisat A, Ghezzi C. Evaluation of anti-atherogenic effects of P2Y12 receptor antagonists in Apolipoprotein E-deficient mice. ARCHIVES OF CARDIOVASCULAR DISEASES SUPPLEMENTS 2019. [DOI: 10.1016/j.acvdsp.2019.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Soleimani B, Rezvanifard M, Ahmadi M. Determination of neutron flux parameters (f, α, φ th and φ e) of the irradiation sites of Isfahan MNSR reactor using empirical and MCNPX2.6 simulation approaches. Appl Radiat Isot 2019; 148:80-86. [PMID: 30925367 DOI: 10.1016/j.apradiso.2019.01.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 01/03/2019] [Accepted: 01/24/2019] [Indexed: 11/18/2022]
Abstract
Miniature Neutron Source reactors (MNSRs) are ideal for applications such as nuclear research, neutron activation analysis, etc., provided that their neutron flux parameters (φth, φe, f and α) are known. This paper present the results of the neutron flux parameters at inner and outer irradiation sites of Isfahan MNSR reactor determined through simulation with MCNPX2.6 code and experimentally using bare and cadmium-covered gold foils irradiation and bare triple (AuZr) monitor methods. In empirical approach, the obtained φth, φe, f [fbare] and α-values were 5.02 × 1011 ncm-2s-1 (±4.5%), 3.13 × 1010 ncm-2s-1 (±2.3%), 16.0 (±6.7%) [17.3 (±9.9%)] and -0.121 (±0.2%), for inner site; and 2.93 × 1011 ncm-2s-1 (±2.3%), 6.48 × 109 ncm-2s-1 (±3.1%), 45.2 (±5.4%) [42.5 (±7.1%)] and -0.011 (±1.8%), respectively, for outer site. In simulation approach, while, they were found to be 4.76 × 1011 ncm-2s-1 (±0.9%), 2.00 × 1010 ncm-2s-1 (±2.2%), 23.8 (±3.1%) and -0.078 (±0.13%), for the inner site; and 2.67 × 1011 ncm-2s-1 (±1.1%), 3.79 × 109 ncm-2s-1 (±5.4%), 70.4 (±6.5%) and -0.017 (±0.4%) for the outer site, respectively. Comparison of empirical and simulation results clearly revealed that: the inner site's φth and f values correspond with those measured during the first startup of the reactor; the values of φth are more reliable than φe,-values, as are the inner site's f and α results in comparison with outer site's values; the inner site's φth and φe are ∼1.7 and 5 times, respectively, larger than those of outer site; and the inner site 's α and f-values are more than 4.8 and 2.4 times larger and less than the outer site's values, respectively.
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Khiyani MF, Ahmadi M, Barbeau J, Feine JS, de Souza RF, Siqueira WL, Emami E. Salivary Biomarkers in Denture Stomatitis: A Systematic Review. JDR Clin Trans Res 2019; 4:312-322. [PMID: 30931724 DOI: 10.1177/2380084419830941] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE Denture stomatitis (DS) is an oral biofilm-associated inflammation of the denture-bearing mucosa. The objective of this review was to identify and evaluate the quality of evidence on the association between the levels of salivary biomarkers and DS among adults with and without palatal DS. MATERIALS AND METHODS Following the PRISMA guidelines, Medline, PubMed, EMBASE, and the Cochrane Central Register for Controlled Trials were searched for eligible studies from the beginning of the archives until December 2018. Experimental and observational studies with adult participants were included that had a control group or subgroup analysis and provided data on salivary biomarkers and DS. Articles in languages other than English or French were excluded. The level of evidence and grades of recommendation were established with the 2011 scale of the Oxford Centre for Evidence-Based Medicine. Additionally, the assessment of methodological quality was conducted with the STROBE statement (Strengthening the Reporting of Observational Studies in Epidemiology) and graded according to the Olmos scale. RESULTS From 1,008 citations, 9 studies were included in the systematic review (8 observational, 1 clinical trial). Seven studies suggested a statistically significant difference in the levels of salivary cytokines (IL-6, CCL3, TGF-β, CXCL8, GM-CSF, and TNF-α) between participants with DS and controls (P < 0.05). In contrast, 2 studies concluded that the difference in the levels of several salivary cytokines (IL2, IL12, IFN-g, IL-4, IL-8, IL-10, IL-17, TNF-α, and ICAM-1) between the groups was not statistically significant. The level of evidence for the majority of studies was 3, while the grade of recommendation for all the studies was B, interpreted as "favorable." In terms of methodological quality, most studies met 50% to 80% of STROBE criteria and were graded B. CONCLUSION Palatal inflammation in DS is significantly associated with the levels of salivary cytokines. KNOWLEDGE TRANSFER STATEMENT The results of this study identified altered levels of specific salivary biomarkers associated with denture stomatitis, which may aid in the early diagnosis and treatment of this disease.
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Helness H, Sun C, Damman S, Ahmadi M, Raspati G, Bjerkelund V, Moldestad G, Hattori K, Kato T, Ando N. High rate filtration for local treatment of combined sewer overflow. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2019; 79:1206-1213. [PMID: 31070600 DOI: 10.2166/wst.2019.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Combined sewer overflows (CSOs) pollute receiving waters and have a negative impact on ecosystem services. In urban areas rehabilitation of the sewer system to avoid CSOs is associated with high investment costs. Furthermore, not all CSOs can be closed due to the need for hydraulic reliability of the system. Local treatment of CSO with high rate filtration offers an alternative to rehabilitation of the sewer system that is flexible with respect to design and has lower investment cost than separating sewage and storm water runoff. Results from DESSIN, a 4-year EU demonstration project, are presented. The results showed on average 50% removal of particulate matter during CSO events, with higher removal (80%) in the initial first flush period. Other constituents, for example heavy metals, were removed through their association with particles. Potential impacts on ecosystem services in the catchment and the sustainability of the solution were assessed.
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayden ME, Hunter ED, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Knapp P, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Starko DM, Stutter G, So C, Tharp TD, Thompson RI, van der Werf DP, Wurtele JS. Observation of the 1S-2P Lyman-α transition in antihydrogen. Nature 2018; 561:211-215. [PMID: 30135588 PMCID: PMC6786973 DOI: 10.1038/s41586-018-0435-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 07/05/2018] [Indexed: 11/09/2022]
Abstract
In 1906, Theodore Lyman discovered his eponymous series of transitions in the extreme-ultraviolet region of the atomic hydrogen spectrum1,2. The patterns in the hydrogen spectrum helped to establish the emerging theory of quantum mechanics, which we now know governs the world at the atomic scale. Since then, studies involving the Lyman-α line-the 1S-2P transition at a wavelength of 121.6 nanometres-have played an important part in physics and astronomy, as one of the most fundamental atomic transitions in the Universe. For example, this transition has long been used by astronomers studying the intergalactic medium and testing cosmological models via the so-called 'Lyman-α forest'3 of absorption lines at different redshifts. Here we report the observation of the Lyman-α transition in the antihydrogen atom, the antimatter counterpart of hydrogen. Using narrow-line-width, nanosecond-pulsed laser radiation, the 1S-2P transition was excited in magnetically trapped antihydrogen. The transition frequency at a field of 1.033 tesla was determined to be 2,466,051.7 ± 0.12 gigahertz (1σ uncertainty) and agrees with the prediction for hydrogen to a precision of 5 × 10-8. Comparisons of the properties of antihydrogen with those of its well-studied matter equivalent allow precision tests of fundamental symmetries between matter and antimatter. Alongside the ground-state hyperfine4,5 and 1S-2S transitions6,7 recently observed in antihydrogen, the Lyman-α transition will permit laser cooling of antihydrogen8,9, thus providing a cold and dense sample of anti-atoms for precision spectroscopy and gravity measurements10. In addition to the observation of this fundamental transition, this work represents both a decisive technological step towards laser cooling of antihydrogen, and the extension of antimatter spectroscopy to quantum states possessing orbital angular momentum.
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Ahmadi M, Cruttenden C, Zhu XH, Chen W, Rajamani R. Flexible MRI Compatible Brain Probes. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:4579-4582. [PMID: 30441371 DOI: 10.1109/embc.2018.8513162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The exact localization of signal recording probes or deep stimulation probes by magnetic resonance imaging (MRI) has significant importance in studying and understanding how the brain functions. But the magnetic susceptibility of the probes itself distorts the MRI image and creates error in position measurement. In this paper we propose an MRI compatible flexible probe with magnetic susceptibility that is well matched with the brain tissue. The well-matched magnetic susceptibility of the probe enables high resolution structural and functional MRI even at ultra-high Bfield strengths. The MRI images shows almost zero artifacts around the implanted probe in the phantom tissue.
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Ahmadi M, Zhang Y, Rajamani R, Timm G, Sezen AS. A Super-Capacitive Pressure Sensor for a Urethral Catheter. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:1-3. [PMID: 30440292 DOI: 10.1109/embc.2018.8513064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Urinary incontinence can be due to neuromuscular or structural problems in either the bladder or the urethra. Urodynamics is often used to analyze the patientspecific cause of urinary incontinence. In urodynamics, a challenging part of the studies involves measurement of the urethral (contact) pressure profile. Here we present an instrumented urethral catheter that is equipped with a novel super-capacitive pressure transducer that is highly sensitive to the applied pressure. A solid ionic electrolyte is used to create a high capacitance device. Through an innovative design the solid electrolyte is made and bounded to a 3d printed soft balloon and then assembled on a 6 Fr urethral catheter. In this paper the design, fabrication and evaluation of the highly-sensitive instrumented catheter's performance are discussed.
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Broisat A, Lemasson B, Ahmadi M, Collomb N, Bacot S, Soubies A, Fagret D, Rémy C, Ghezzi C, Barbier EL. Mapping of brain tissue hematocrit in glioma and acute stroke using a dual autoradiography approach. Sci Rep 2018; 8:9878. [PMID: 29959336 PMCID: PMC6026160 DOI: 10.1038/s41598-018-28082-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 06/15/2018] [Indexed: 11/09/2022] Open
Abstract
Hematocrit (Hct) determines the ability of blood to carry oxygen. While changes in systemic Hct are known to impact stroke or tumor control, changes in local (tissue) Hct (tHct) induced by these diseases have however received little attention. In this study, we evaluate tHct in acute stroke and in glioma models using a new approach to map tHct across the brain, a dual isotope autoradiography, based on injections of 125I-labeled albumin and 99mTc-lalbeled red blood cells in the same animal. For validation purpose, tHct was mapped in the rat brain (i) under physiological conditions, (ii) following erythropoietin injection, and (iii) following hemodilution. Then, tHct was then mapped in stroke (middle cerebral artery occlusion) and tumor models (9LGS and C6). The mean tHct values observed in healthy brains (tHct = 29 ± 1.3%), were modified as expected by erythropoietin (tHct = 36.7 ± 2.6%) and hemodilution (tHct = 24.2 ± 2.4%). Using the proposed method, we observed a local reduction, spatially heterogeneous, in tHct following acute stroke (tHct = 19.5 ± 2.5%) and in both glioma models (9LGS: tHct = 18.5 ± 2.3%, C6: tHct = 16.1 ± 1.2%). This reduction and this heterogeneity in tHct observed in stroke and glioma raises methodological issues in perfusion imaging techniques where tHct is generally overlooked and could impact therapeutic strategies.
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Knapp P, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stutter G, So C, Tharp TD, Thompson RI, van der Werf DP, Wurtele JS. Characterization of the 1S-2S transition in antihydrogen. Nature 2018; 557:71-75. [PMID: 29618820 PMCID: PMC6784861 DOI: 10.1038/s41586-018-0017-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/06/2018] [Indexed: 11/09/2022]
Abstract
In 1928, Dirac published an equation 1 that combined quantum mechanics and special relativity. Negative-energy solutions to this equation, rather than being unphysical as initially thought, represented a class of hitherto unobserved and unimagined particles-antimatter. The existence of particles of antimatter was confirmed with the discovery of the positron 2 (or anti-electron) by Anderson in 1932, but it is still unknown why matter, rather than antimatter, survived after the Big Bang. As a result, experimental studies of antimatter3-7, including tests of fundamental symmetries such as charge-parity and charge-parity-time, and searches for evidence of primordial antimatter, such as antihelium nuclei, have high priority in contemporary physics research. The fundamental role of the hydrogen atom in the evolution of the Universe and in the historical development of our understanding of quantum physics makes its antimatter counterpart-the antihydrogen atom-of particular interest. Current standard-model physics requires that hydrogen and antihydrogen have the same energy levels and spectral lines. The laser-driven 1S-2S transition was recently observed 8 in antihydrogen. Here we characterize one of the hyperfine components of this transition using magnetically trapped atoms of antihydrogen and compare it to model calculations for hydrogen in our apparatus. We find that the shape of the spectral line agrees very well with that expected for hydrogen and that the resonance frequency agrees with that in hydrogen to about 5 kilohertz out of 2.5 × 1015 hertz. This is consistent with charge-parity-time invariance at a relative precision of 2 × 10-12-two orders of magnitude more precise than the previous determination 8 -corresponding to an absolute energy sensitivity of 2 × 10-20 GeV.
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Ahmadi M, Rassouli M, Karami M, Abasszadeh A, Poormansouri S. Care burden and its Related Factors in Parents of Children with Cancer. ACTA ACUST UNITED AC 2018. [DOI: 10.29252/ijn.31.111.40] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Seyfi F, Soleimani B, Hosseini MA, Rezvanifard M, Ahmadi M. The feasibility of 198Au production in Isfahan MNSR research reactor through a multi-stage approach. J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-5810-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Butler E, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Ishida A, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stracka S, Stutter G, So C, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Erratum: Observation of the hyperfine spectrum of antihydrogen. Nature 2018; 553:530. [PMID: 29258296 DOI: 10.1038/nature24663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This corrects the article DOI: 10.1038/nature23446.
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, So C, Stutter G, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Enhanced Control and Reproducibility of Non-Neutral Plasmas. PHYSICAL REVIEW LETTERS 2018; 120:025001. [PMID: 29376718 DOI: 10.1103/physrevlett.120.025001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Indexed: 06/07/2023]
Abstract
The simultaneous control of the density and particle number of non-neutral plasmas confined in Penning-Malmberg traps is demonstrated. Control is achieved by setting the plasma's density by applying a rotating electric field while simultaneously fixing its axial potential via evaporative cooling. This novel method is particularly useful for stabilizing positron plasmas, as the procedures used to collect positrons from radioactive sources typically yield plasmas with variable densities and particle numbers; it also simplifies optimization studies that require plasma parameter scans. The reproducibility achieved by applying this technique to the positron and electron plasmas used by the ALPHA antihydrogen experiment at CERN, combined with other developments, contributed to a 10-fold increase in the antiatom trapping rate.
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Ahmadi M, Khurshid K, Sanelli PC, Jalal S, Chahal T, Norbash A, Nicolaou S, Castillo M, Khosa F. Influences for Gender Disparity in Academic Neuroradiology. AJNR Am J Neuroradiol 2017; 39:18-23. [PMID: 29191872 DOI: 10.3174/ajnr.a5443] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 08/08/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE There has been extensive interest in promoting gender equality within radiology, a predominately male field. In this study, our aim was to quantify gender representation in neuroradiology faculty rankings and determine any related factors that may contribute to any such disparity. MATERIALS AND METHODS We evaluated the academic and administrative faculty members of neuroradiology divisions for all on-line listed programs in the US and Canada. After excluding programs that did not fulfill our selection criteria, we generated a short list of 85 US and 8 Canadian programs. We found 465 faculty members who met the inclusion criteria for our study. We used Elsevier's SCOPUS for gathering the data pertaining to the publications, H-index, citations, and tenure of the productivity of each faculty member. RESULTS Gender disparity was insignificant when analyzing academic ranks. There are more men working in neuroimaging relative to women (χ2 = 0.46; P = .79). However, gender disparity was highly significant for leadership positions in neuroradiology (χ2 = 6.76; P = .009). The median H-index was higher among male faculty members (17.5) versus female faculty members (9). Female faculty members have odds of 0.84 compared with male faculty members of having a higher H-index, adjusting for publications, citations, academic ranks, leadership ranks, and interaction between gender and publications and gender and citations (9). CONCLUSIONS Neuroradiology faculty members follow the same male predominance seen in many other specialties of medicine. In this study, issues such as mentoring, role models, opportunities to engage in leadership/research activities, funding opportunities, and mindfulness regarding research productivity are explored.
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Golabian A, Hosseini MA, Ahmadi M, Soleimani B, Rezvanifard M. The feasibility study of 177Lu production in Miniature Neutron Source Reactors using a multi-stage approach in Isfahan, Iran. Appl Radiat Isot 2017; 131:62-66. [PMID: 29173809 DOI: 10.1016/j.apradiso.2017.11.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Revised: 10/10/2017] [Accepted: 11/13/2017] [Indexed: 11/29/2022]
Abstract
Miniature neutron source reactors (MNSRs) are among the safest and economic research reactors with potentials to be used for neutron studies. This manuscript explores the feasibility of 177Lu production in Isfahan MNSR reactor using direct production route. In this study, to assess the specific activity of the produced radioisotope, a simulation was carried out through the MCNPX2.6 code. The simulation was validated by irradiating a lutetium disc-like (99.98 chemical purity) at the thermal neutron flux of 5 × 1011 ncm2s-1 and an irradiation time of 4min. After the spectrometry of the irradiated sample, the experimental results of 177Lu production were compared with the simulation results. In addition, factor from the simulation was extracted by replacing it in the related equations in order to calculate specific activity through a multi-stage approach, and by using different irradiation techniques. The results showed that the simulation technique designed in this study is in agreement with the experimental approach (with a difference of approximately 3%). It was also found that the maximum 177Lu production at the maximum flux and irradiation time allows access to 723.5mCi/g after 27 cycles. Furthermore, the comparison of irradiation techniques showed that increasing the irradiation time is more effective in 177Lu production efficiency than increasing the number of irradiation cycles. In a way that increasing the irradiation time would postpone the saturation of the productions. On the other hand, it was shown that the choice of an appropriate irradiation technique for 177Lu production can be economically important in term of the effective fuel consumption in the reactor.
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Butler E, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Ishida A, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stracka S, Stutter G, So C, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Observation of the hyperfine spectrum of antihydrogen. Nature 2017; 548:66-69. [PMID: 28770838 DOI: 10.1038/nature23446] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 06/30/2017] [Indexed: 11/09/2022]
Abstract
The observation of hyperfine structure in atomic hydrogen by Rabi and co-workers and the measurement of the zero-field ground-state splitting at the level of seven parts in 1013 are important achievements of mid-twentieth-century physics. The work that led to these achievements also provided the first evidence for the anomalous magnetic moment of the electron, inspired Schwinger's relativistic theory of quantum electrodynamics and gave rise to the hydrogen maser, which is a critical component of modern navigation, geo-positioning and very-long-baseline interferometry systems. Research at the Antiproton Decelerator at CERN by the ALPHA collaboration extends these enquiries into the antimatter sector. Recently, tools have been developed that enable studies of the hyperfine structure of antihydrogen-the antimatter counterpart of hydrogen. The goal of such studies is to search for any differences that might exist between this archetypal pair of atoms, and thereby to test the fundamental principles on which quantum field theory is constructed. Magnetic trapping of antihydrogen atoms provides a means of studying them by combining electromagnetic interaction with detection techniques that are unique to antimatter. Here we report the results of a microwave spectroscopy experiment in which we probe the response of antihydrogen over a controlled range of frequencies. The data reveal clear and distinct signatures of two allowed transitions, from which we obtain a direct, magnetic-field-independent measurement of the hyperfine splitting. From a set of trials involving 194 detected atoms, we determine a splitting of 1,420.4 ± 0.5 megahertz, consistent with expectations for atomic hydrogen at the level of four parts in 104. This observation of the detailed behaviour of a quantum transition in an atom of antihydrogen exemplifies tests of fundamental symmetries such as charge-parity-time in antimatter, and the techniques developed here will enable more-precise such tests.
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Hosseini MA, Ahmadi M. Miniature Neutron Source Reactors in medical research: achievements and challenges. J Radioanal Nucl Chem 2017. [DOI: 10.1007/s10967-017-5554-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Butler E, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Ishida A, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stracka S, Stutter G, So C, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Antihydrogen accumulation for fundamental symmetry tests. Nat Commun 2017; 8:681. [PMID: 28947794 PMCID: PMC5613003 DOI: 10.1038/s41467-017-00760-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 07/20/2017] [Indexed: 11/18/2022] Open
Abstract
Antihydrogen, a positron bound to an antiproton, is the simplest anti-atom. Its structure and properties are expected to mirror those of the hydrogen atom. Prospects for precision comparisons of the two, as tests of fundamental symmetries, are driving a vibrant programme of research. In this regard, a limiting factor in most experiments is the availability of large numbers of cold ground state antihydrogen atoms. Here, we describe how an improved synthesis process results in a maximum rate of 10.5 ± 0.6 atoms trapped and detected per cycle, corresponding to more than an order of magnitude improvement over previous work. Additionally, we demonstrate how detailed control of electron, positron and antiproton plasmas enables repeated formation and trapping of antihydrogen atoms, with the simultaneous retention of atoms produced in previous cycles. We report a record of 54 detected annihilation events from a single release of the trapped anti-atoms accumulated from five consecutive cycles. Antihydrogen studies are important in testing the fundamental principles of physics but producing antihydrogen in large amounts is challenging. Here the authors demonstrate an efficient and high-precision method for trapping and stacking antihydrogen by using controlled plasma.
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Moghadam MZ, Hassanajili S, Esmaeilzadeh F, Ayatollahi M, Ahmadi M. Formation of porous HPCL/LPCL/HA scaffolds with supercritical CO 2 gas foaming method. J Mech Behav Biomed Mater 2017; 69:115-127. [DOI: 10.1016/j.jmbbm.2016.12.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 12/18/2016] [Accepted: 12/20/2016] [Indexed: 11/25/2022]
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Ahmadi M, Salehi B. The link between intergenic distances and controls exerted on the transcriptional regulation; an inferential approach. ACTA ACUST UNITED AC 2017; 63:14-19. [PMID: 28364780 DOI: 10.14715/cmb/2017.63.2.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 03/25/2017] [Indexed: 11/18/2022]
Abstract
The position of genes along the genome is an important evolutionary factor for organizing gene regulation. Hence, transcriptional regulatory network have been studied much more extensively from gene distributions rather than other viewpoints. The systematics of intergenic distances, therefore, should be taken into account as an important source of information on the controls exerted on gene expression by various biological mechanisms. Here we study a collection of features including, intergenic and interoperonic distances, distances between isolated genes, distances between regulatory genes and distances between isolated and regulatory genes/operons in order to provide a more informative picture of gene distributions via firstly discovering the statistical model of these features. We find that all these features significantly follow the lognormal distribution. Then we test a few important biological hypotheses particularly in relation to controls exerted in the transcriptional regulatory network in a completely inferential approach using generalized p-value based on the discovered model. We find that mean distances of isolated genes significantly is less than that of regulatory genes. These findings are consistent with the previous evidences that many biological variables, especially in relation to systems biology, follow lognormal distribution. furthermore, our results inferentially support the crucial hypothesis on the two distinct logical types of control, namely digital control (i.e. control mediated by specific transcription factors) and analog control (i.e. control mediated by distribution of supercoiling energy and based on gene neighborhood) previously proposed by studying expression patterns.
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Ahmadi M, Foozonkhah S, Shahmoradi L, Mahmodabadi AD. Messaging standard requirements for electronic health records in Islamic Republic of Iran: a Delphi study. EASTERN MEDITERRANEAN HEALTH JOURNAL 2017; 22:794-801. [PMID: 28177109 DOI: 10.26719/2016.22.11.794] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 07/03/2016] [Indexed: 11/09/2022]
Abstract
The present descriptive-comparative study was conducted to give an overview of the messaging standards that are necessary for interoperable electronic health records (EHRs). We designed a preliminary model after data collection and compared the messaging standards of Health Level Seven (HL7) and the International Organization for Standardization (ISO). The data were assessed with the Delphi technique. A comprehensive model for the messaging standards of EHRs in the Islamic Republic of Iran was presented in three pivots: structural characteristics (standard for all EHRs, XML-based and object-oriented messages, and dual model); model specifications (reference model, archetypes and classes of reference model), and general features (distinct ontology, mapping with other standards, and using reference archetypes for exchanging documents). In conclusion, we gave an overview of messaging standards for the interoperability of EHRs and experts selected ISO13606 as a suitable standard for the Islamic Republic of Iran.
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Ahmadi M, Rajaei Z, Hadjzadeh MA, Nemati H, Hosseini M. Crocin improves spatial learning and memory deficits in the Morris water maze via attenuating cortical oxidative damage in diabetic rats. Neurosci Lett 2017; 642:1-6. [PMID: 28137647 DOI: 10.1016/j.neulet.2017.01.049] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 01/11/2017] [Accepted: 01/19/2017] [Indexed: 01/29/2023]
Abstract
The purpose of the current study was to examine the influence of crocin on improving spatial memory deficits and cerebral oxidative damage in streptozotocin-induced diabetic rats. Crocin was administered intraperitoneally daily at doses of 15, 30 and 60mg/kg for 6 weeks. Spatial memory performance was measured in rats by the Morris water maze paradigm. Lipid peroxidation and total thiol levels as parameters of oxidative stress were assessed in the cerebral cortex at the end of week 6. Diabetic rats showed spatial learning and memory deficits in the Morris water maze which was accompanied by increased lipid peroxidation levels in the cerebral cortex. By contrast, chronic treatment with crocin (15, 30 and 60mg/kg, ip, 6 weeks) improved cognitive performance and lowered hyperglycaemia and oxidative stress in diabetic rats. In conclusion, the results suggest that beneficial effects of crocin on streptozotocin-induced memory dysfunction may be attributed to its antidiabetic and antioxidant activity, which could find clinical use in treating cognitive dysfunction in diabetics.
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Afrashtehfar KI, Ahmadi M, Emami E, Abi-Nader S, Tamimi F. Failure of single-unit restorations on root filled posterior teeth: a systematic review. Int Endod J 2017; 50:951-966. [PMID: 27870102 DOI: 10.1111/iej.12723] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 11/17/2016] [Indexed: 01/08/2023]
Abstract
This systematic review investigated the failure rate of conventional single-unit restorations in root filled posterior permanent teeth. Two reviewers independently applied eligibility criteria, extracted data and assessed the quality of the evidence of each included study according to the Cochrane Collaboration's procedures for randomized control trials (RCTs) and the STROBE criteria for observational studies. The MEDLINE (via Ovid), EMBASE (via Ovid), Cochrane Oral Health Group Trials Register and CENTRAL (via Cochrane Library) databases were searched electronically (January 1993 to week 1, February 2015). This was complemented by an additional hand search of selected journals and the references of relevant studies. Clinical studies published on root filled single-unit restorative treatments with a mean follow-up period of at least 3 years were selected. The outcome measured was clinical or radiological failure. Overall, the four RCTs and the single observational study included were of low and high quality, respectively. Therefore, a meta-analysis was not possible. The pooled mean failure rates were reported according to the type of treatment and remaining coronal tooth structure. The current evidence suggested that the failure rates of the treatments may depend on the amount of remaining tooth structure and type of treatment. Post-retained crowns were associated with the most favourable outcome in teeth with one to two remaining coronal tooth wall(s), whereas post-free crowns were superior when greater tooth structure was available. Restorations in teeth without ferrules had such a high rate of failure that other treatment options should be considered.
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