3,016 research outputs found

    Subwavelength atom localization via amplitude and phase control of the absorption spectrum

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    We propose a scheme for subwavelength localization of an atom conditioned upon the absorption of a weak probe field at a particular frequency. Manipulating atom-field interaction on a certain transition by applying drive fields on nearby coupled transitions leads to interesting effects in the absorption spectrum of the weak probe field. We exploit this fact and employ a four-level system with three driving fields and a weak probe field, where one of the drive fields is a standing-wave field of a cavity. We show that the position of an atom along this standing wave is determined when probe field absorption is measured. We find that absorption of the weak probe field at a certain frequency leads to subwavelength localization of the atom in either of the two half-wavelength regions of the cavity field by appropriate choice of the system parameters. We term this result as sub-half-wavelength localization to contrast it with the usual atom localization result of four peaks spread over one wavelength of the standing wave. We observe two localization peaks in either of the two half-wavelength regions along the cavity axis.Comment: Accepted for publication to Physical Review

    What information can we obtain from the yield ratio π/π+\pi^-/\pi^+ in heavy-ion collisions ?

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    The recently reported data on the yield ratio π/π+\pi^-/\pi^+ in central rapidity region of heavy-ion collisions are analyzed by theoretical formula which accounts for Coulomb interaction between central charged fragment (CCF) consisting of nearly stopped nucleons with effective charge Z_{\mbox{\scriptsize eff}} and charged pions produced in the same region of the phase space. The Coulomb wave function method is used instead of the usual Gamow factor in order to account for the finite production range of pions, β\beta. For Gaussian shape of the pion production sources it results in a quasi-scaling in β\beta and Z_{\mbox{\scriptsize eff}} which makes determination of parameters β\beta and Z_{\mbox{\scriptsize eff}} from the existing experimental data difficult. Only sufficiently accurate data taken in the extreme small mTm_{\scriptscriptstyle T}-mπm_{\pi} region, where this quasi-scaling is broken, could be used for this purpose.Comment: 7 pages, Latex type, 8 figure

    The spectrum of MEFV gene mutations and genotype-phenotype correlation in Egyptian patients with familial Mediterranean fever

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    Background: Familial Mediterranean fever (FMF) is an autosomal recessive disease mainly affecting subjects of the Mediterranean origin. It is an auto-inflammatory periodic disorder that is caused by mutations in the Mediterranean fever gene (MEFV) located on chromosome 16.Methods: The current study was designed to assess the prevalence and frequency of different MEFV gene mutations among 104 FMF clinically diagnosed Egyptian patients and to evaluate the change extent in the values of some biochemical markers (ESR, CRP, Fibrinogen-C, SAA and IL1) in different participants with different FMF severity scores.Results: According to allele status 28 patients (27%) were homozygous mutation carriers, 38 (36.5%) were with compound heterozygous mutations and 38 (36.5%) were identified as heterozygous for one of the studied mutations. Of the studied mutations, M694I, E148Q, V726A, M680I, and M694V accounted for 28.1%, 26.8%, 16.9%, and 11.3% of mutations respectively. The R761H and P369S mutations were rarely encountered mutations (1.4%). The clinical features with M694I were associated with more severe clinical course. There is a drastic elevation in the levels of estimated parameters as their levels were increased as long as the severity of the disease increased.Conclusions: The diagnosis of FMF cannot be performed on the basis of genetic testing or clinical criteria alone. So, we recommended the combination between clinical and molecular profiling for FMF diagnosis and scoring

    Coulomb Effect: A Possible Probe for the Evolution of Hadronic Matter

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    Electromagnetic field produced in high-energy heavy-ion collisions contains much useful information, because the field can be directly related to the motion of the matter in the whole stage of the reaction. One can divide the total electromagnetic field into three parts, i.e., the contributions from the incident nuclei, non-participating nucleons and charged fluid, the latter consisting of strongly interacting hadrons or quarks. Parametrizing the space-time evolution of the charged fluid based on hydrodynamic model, we study the development of the electromagnetic field which accompanies the high-energy heavy-ion collisions. We found that the incident nuclei bring a rather strong electromagnetic field to the interaction region of hadrons or quarks over a few fm after the collision. On the other hand, the observed charged hadrons' spectra are mostly affected (Coulomb effect) by the field of the charged fluid. We compare the result of our model with experimental data and found that the model reproduces them well. The pion yield ratio pi^-/pi+ at a RHIC energy, Au+Au 100+100 GeV/nucleon, is also predicted.Comment: 23 pages, RevTex, 19 eps figures, revised versio

    Environmental life cycle assessment and techno-economic analysis of triboelectric nanogenerators

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    As the world economy grows and industrialization of the developing countries increases, the demand for energy continues to rise. Triboelectric nanogenerators (TENGs) have been touted as having great potential for low-carbon, non-fossil fuel energy generation. Mechanical energies from, amongst others, body motion, vibration, wind and waves are captured and converted by TENGs to harvest electricity, thereby minimizing global fossil fuel consumption. However, only by ascertaining performance efficiency along with low material and manufacturing costs as well as a favorable environmental profile in comparison with other energy harvesting technologies, can the true potential of TENGs be established. This paper presents a detailed techno-economic lifecycle assessment of two representative examples of TENG modules, one with a high performance efficiency (Module A) and the other with a lower efficiency (Module B) both fabricated using low-cost materials. The results are discussed across a number of sustainability metrics in the context of other energy harvesting technologies, notably photovoltaics. Module A possesses a better environmental profile, lower cost of production, lower CO2 emissions and shorter energy payback period (EPBP) compared to Module B. However, the environmental profile of Module B is slightly degraded due to the higher content of acrylic in its architecture and higher electrical energy consumption during fabrication. The end of life scenario of acrylic is environmentally viable given its recyclability and reuse potential and it does not generate toxic gases that are harmful to humans and the environment during combustion processes due to its stability during exposure to ultraviolet radiation. Despite the adoption of a less optimum laboratory manufacturing route, TENG modules generally have a better environmental profile than commercialized Si based and organic solar cells, but Module B has a slightly higher energy payback period than PV technology based on perovskite-structured methyl ammonium lead iodide. Overall, we recommend that future research into TENGs should focus on improving system performance, material optimization and more importantly improving their lifespan to realize their full potential

    The Bouveret Syndrome: An Unusual Cause of Hematemesis

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    Gallstones are usually silent. Less commonly, patients with cholelithiasis develop symptoms and/or complications; biliary fistula occurs in 3% to 5% of the cases. When a large stone is passed and occludes the duodenum, gastric outlet obstruction (the Bouveret syndrome) may result. In reported cases, the stones are usually larger than 2.5 cm. The usual presenting symptoms are those of bowel obstruction: abdominal pain, nausea, and vomiting. Less commonly, the patients experience melena and, rarely, hematemesis. We describe a patient who had the largest stone reported to cause hematemesis rather than bowel obstruction and to be diagnosed endoscopically. The 5 X 4 X 3 cm stone was extracted surgically. Endoscopic diagnosis and extraction of stones up to 3 cm in size has been reported, avoiding the need for surgery

    NAD(P)H:quinone oxidoreductase 1 inducer activity of some novel anilinoquinazoline derivatives

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    The Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response elements pathway enables cells to survive oxidative stress conditions through regulating the expression of cytoprotective enzymes such as NAD(P)H:quinone oxidoreductase 1 (NQO1). This work presents the design and synthesis of novel anilinoquinazoline derivatives (2–16a) and evaluation of their NQO1 inducer activity in murine cells. Molecular docking of the new compounds was performed to assess their ability to inhibit Keap1–Nrf2 protein–protein interaction through occupying the Keap1–Nrf2-binding domain, which leads to Nrf2 accumulation and enhanced gene expression of NQO1. Docking results showed that all compounds can potentially interact with Keap1; however, 1,5-dimethyl-2-phenyl-4-(2-phenylquinazolin-4-ylamino)-1,2-dihydropyrazol-3-one (9), the most potent inducer, showed the largest number of interactions with key amino acids in the binding pocket (Arg483, Tyr525, and Phe478) compared to the native ligand or any other compound in this series

    Quasiscaling in the analysis of the yield ratio π/π+\pi^-/\pi^+: Mathematical structure and estimation of source size

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    Recently we have found that integral of the squared Coulomb wave function describing systemcomposed of charged pion and central charged fragment ZeffZ_{eff} protons, ψr(r)2|\psi_r(r)|^2, times pion source function ρ(r)\rho(r) (of the size β\beta), \intdr |\psi_r(r)|^2 \rho(r), shows a quasiscaling behavior. This is approximately invariant under the following transformation: (β,Zeff)(λβ,λZeff)(\beta,Z_{eff}) \to (\lambda\beta,\lambda Z_{eff}); λ>0\lambda >0. We called such behavior βZeff\beta-Z_{eff} quasiscaling. We examine this quasiscaling behavior in detail. In particular we provide a semi-analytical examination of this behavior and confirm it for the exponential pionic source functions in addition to the Gaussian ones and for the production of K mesons as well. When combined with the results of the HBT, a result of the yield ratio allows us to estimate the size of the central charged fragment (CCF) to be 125Zeff150125\le Z_{eff}\le 150 for Pb+Pb collisions at energy 158 GeV/nucleon. From our estimation, the baryon number density 0.024nB0.0360.024 \le n_{B}\le0.036 [1/fm^3] is obtained.Comment: 7 pages, RevTex, 6figure
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