| 61. |
- Abdullaev, Fatkhulla, et al.
(författare)
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Collective dynamics of Fermi-Bose mixtures with an oscillating scattering length
- 2019
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American Physical Society. - 1050-2947 .- 1094-1622. ; 99:3
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Tidskriftsartikel (refereegranskat)abstract
- Collective oscillations of superfluid mixtures of ultra cold fermionic and bosonic atoms are investigated while varying the fermion-boson scattering length. We study the dynamics with respect to excited center of mass modes and breathing modes in the mixture. Parametric resonances are also analyzed when the scattering length varies periodically in time, by comparing partial differential equation (PDE) models and ordinary differential equation (ODE) models for the dynamics. An application to the recent experiment with fermionic Li-6 and bosonic Li-7 atoms, which approximately have the same masses, is discussed.
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| 62. |
- Abdullaev, Fatkhulla, et al.
(författare)
-
Faraday waves in quasi-one-dimensional superfluid Fermi-Bose mixtures
- 2013
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American Physical Society. - 1050-2947 .- 1094-1622. ; 87:2
-
Tidskriftsartikel (refereegranskat)abstract
- The generation of Faraday waves in superfluid Fermi-Bose mixtures in elongated traps is investigated. The generation of waves is achieved by periodically changing a parameter of the system in time. Two types of modulations of parameters are considered: a variation of the fermion-boson scattering length and the boson-boson scattering length. We predict the properties of the generated Faraday patterns and study the parameter regions where they can be excited.
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| 63. |
- Abdullaev, F. Kh., et al.
(författare)
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Management of solitons in medium with competing cubic and quadratic nonlinearities
- 2023
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Ingår i: Optik (Stuttgart). - : Elsevier. - 0030-4026 .- 1618-1336. ; 274
-
Tidskriftsartikel (refereegranskat)abstract
- Management of solitons in media with competing quadratic and cubic nonlinearities is investigated. Two schemes, using rapid modulations of a mismatch parameter, and of the Kerr nonlinearity parameter are studied. For both cases, the averaged in time wave equations are derived. In the case of mismatch management, the region of the parameters where stabilization is possible is found. In the case of Kerr nonlinearity management, it is shown that the effective chi(2) nonlinearity depends on the intensity imbalance between fundamental (FH) and second (SH) harmonics. Predictions obtained from the averaged equations are confirmed by numerical simulations of the full PDE’s.
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| 64. |
- Abdullaev, F Kh, et al.
(författare)
-
Matter waves in atomic-molecular BEC with Feshbach resonance management
- 2021
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Ingår i: OSA Nonlinear Optics 2021. - : Optical Society of America. - 9781943580972
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Konferensbidrag (refereegranskat)abstract
- Dynamics of matter waves in the atomic to molecular condensate transition with a time modulated atomic scattering length is investigated. The conditions for dynamical suppression of association of atoms into the molecular field are obtained.
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| 65. |
- Abdullaev, F. Kh., et al.
(författare)
-
Nonlinearity managed vector solitons
- 2023
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Ingår i: Physics Letters A. - : Elsevier. - 0375-9601 .- 1873-2429. ; 491
-
Tidskriftsartikel (refereegranskat)abstract
- The evolution of vector solitons under nonlinearity management is studied. The averaged over strong and rapid modulations in time of the inter-species interactions vector Gross-Pitaevskii equation (GPE) is derived. The averaging gives the appearance of the effective nonlinear quantum pressure depending on the population of the other component. Using this system of equations, the existence and stability of the vector solitons under the action of the strong nonlinearity management (NM) is investigated. Using a variational approach the parameters of NM vector solitons are found. The numerical simulations of the full time-dependent coupled GPE confirms the theoretical predictions.
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| 66. |
- Abdullaev, Fatkhulla, et al.
(författare)
-
Matter waves in atomic-molecular condensates with Feshbach resonance management
- 2021
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - : American Physical Society. - 1063-651X .- 1095-3787. ; 104:2
-
Tidskriftsartikel (refereegranskat)abstract
- The dynamics of matter waves in the atomic to molecular condensate transition with a time-modulated atomic scattering length is investigated. Both the cases of rapid and slow modulations are studied. In the case of rapid modulations, the average over oscillations for the system is derived. The corresponding conditions for dynamical suppression of the association of atoms into the molecular field, or of second-harmonic generation in nonlinear optical systems, are obtained. For the case of slow modulations, we find resonant enhancement in the molecular field. We then illustrate chaos in the atomic-molecular BEC system. We suggest a sequential application of the two types of modulations, slow and rapid, when producing molecules.
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| 67. |
- Abdullaev, Farakhulla, et al.
(författare)
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Zeno effect and switching of solitons in nonlinear couplers
- 2011
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Ingår i: Optics Letters. - : Optical Society of America. - 0146-9592 .- 1539-4794. ; 36:23, s. 4566-4568
-
Tidskriftsartikel (refereegranskat)abstract
- The Zeno effect is investigated for soliton type pulses in a nonlinear directional coupler with dissipation. The effect consists in increase of the coupler transparency with increase of the dissipative losses in one of the arms. It is shown that localized dissipation can lead to switching of solitons between the arms. Power losses accompanying the switching can be fully compensated by using a combination of dissipative and active (in particular, parity-time-symmetric) segments.
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| 68. |
- AbdulWahab, Atqah, et al.
(författare)
-
The emergence of multidrug-resistant Pseudomonas aeruginosa in cystic fibrosis patients on inhaled antibiotics
- 2017
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Ingår i: Lung India. - : Medknow Publications. - 0970-2113 .- 0974-598X. ; 34:6, s. 527-531
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Multidrug-resistant Pseudomonas aeruginosa (MDR-PA) is an important and growing issue in the care of patients with cystic fibrosis (CF), and a major cause of morbidity and mortality.Objective: The objective of the study was to describe the frequency of MDR-PA recovered from the lower respiratory samples of pediatric and adult CF patients, and its antibiotic resistance pattern to commonly used antimicrobial agents including beta-lactams, aminoglycosides, and fluoroquinolones.Materials and Methods: The lower respiratory isolates of P. aeruginosa were obtained from inpatients and outpatients CF clinics from a tertiary care teaching hospital for the period from October 2014 to September 2015. The identification and antimicrobial susceptibility for all the isolates were performed by using the BD Phoenix (TM) and E-test in compliance with Clinical and Laboratory Standards Institute (CLSI) guidelines.Results: A total of 61 P. aeruginosa samples were isolated from thirty CF patients from twenty families. Twelve sputum samples were positive for MDR-PA (seven nonmucoid and five mucoid isolates) from five CF patients (five families) with moderate-to-very severe lung disease given MDR-PA frequency of 19.7%. The median age of the study group was 20 (range 10-30) years. Three CF patients were on chronic inhaled tobramycin and two on nebulized colistin. The antimicrobial patterns of isolates MDR-PA showed the highest rate of resistance toward each gentamycin, amikacin, and cefepime (100%), followed by 91.7% to ciprofloxacin, 75% to tobramycin, 58.3% to meropenem, and 50% to piperacillin-tazobactam. None of the isolates were resistant to colistin during the study period.Conclusion: The study results emphasize that the emergence of a significant problem in the clinical isolates of P. aeruginosa in CF patients that dictate appropriate attention to the antibiotic management after proper surveillance.
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| 69. |
- Abdurahman, Samir, 1965-, et al.
(författare)
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Activity of the small modified amino acid alpha-hydroxy glycineamide on in vitro and in vivo human immunodeficiency virus type 1 capsid assembly and infectivity
- 2008
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Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 52:10, s. 3737-3744
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Tidskriftsartikel (refereegranskat)abstract
- Upon maturation of the human immunodeficiency virus type 1 (HIV-1) virion, proteolytic cleavage of the Gag precursor protein by the viral protease is followed by morphological changes of the capsid protein p24, which will ultimately transform the virus core from an immature spherical to a mature conical structure. Virion infectivity is critically dependent on the optimal semistability of the capsid cone structure. We have reported earlier that glycineamide (G-NH(2)), when added to the culture medium of infected cells, inhibits HIV-1 replication and that HIV-1 particles with aberrant core structures were formed. Here we show that it is not G-NH(2) itself but a metabolite thereof, alpha-hydroxy-glycineamide (alpha-HGA), that is responsible for the antiviral activity. We show that alpha-HGA inhibits the replication of clinical HIV-1 isolates with acquired resistance to reverse transcriptase and protease inhibitors but has no effect on the replication of any of 10 different RNA and DNA viruses. alpha-HGA affected the ability of the HIV-1 capsid protein to assemble into tubular or core structures in vitro and in vivo, probably by binding to the hinge region between the N- and C-terminal domains of the HIV-1 capsid protein as indicated by matrix-assisted laser desorption ionization-mass spectrometry results. As an antiviral compound, alpha-HGA has an unusually simple structure, a pronounced antiviral specificity, and a novel mechanism of antiviral action. As such, it might prove to be a lead compound for a new class of anti-HIV substances.
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| 70. |
- Abdurahman, Samir, 1965-, et al.
(författare)
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Isolation and characterization of a small antiretroviral molecule affecting HIV-1 capsid morphology
- 2009
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Ingår i: Retrovirology. - : Springer Science and Business Media LLC. - 1742-4690. ; 6, s. 34-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Formation of an HIV-1 particle with a conical core structure is a prerequisite for the subsequent infectivity of the virus particle. We have previously described that glycineamide (G-NH2) when added to the culture medium of infected cells induces non-infectious HIV-1 particles with aberrant core structures. Results: Here we demonstrate that it is not G-NH2 itself but a metabolite thereof that displays antiviral activity. We show that conversion of G-NH2 to its antiviral metabolite is catalyzed by an enzyme present in bovine and porcine but surprisingly not in human serum. Structure determination by NMR suggested that the active G-NH2 metabolite was alpha-hydroxy-glycineamide (alpha-HGA). Chemically synthesized alpha-HGA inhibited HIV-1 replication to the same degree as G-NH2, unlike a number of other synthesized analogues of G-NH2 which had no effect on HIV-1 replication. Comparisons by capillary electrophoresis and HPLC of the metabolite with the chemically synthesized alpha-HGA further confirmed that the antiviral G-NH2-metabolite indeed was alpha-HGA. Conclusion: alpha-HGA has an unusually simple structure and a novel mechanism of antiviral action. Thus, alpha-HGA could be a lead for new antiviral substances belonging to a new class of anti-HIV drugs, i.e. capsid assembly inhibitors.
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