4 results
Magnetic field-induced signal enhancement in laser-produced lead plasma
- M. Akhtar, A. Jabbar, N. Ahmed, S. Mehmood, Z.A. Umar, R. Ahmed, M.A. Baig
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- Journal:
- Laser and Particle Beams / Volume 37 / Issue 1 / March 2019
- Published online by Cambridge University Press:
- 25 March 2019, pp. 67-78
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Laser-induced breakdown spectroscopy has been exploited to investigate the laser-produced lead plasma with and without external magnetic field. Plasma on the lead surface was generated by focusing a beam of a Nd:YAG laser (532 nm). An external magnetic field was applied across the laser-produced plasma; its value was varied from 0.3 to 0.7 T and the time-integrated spectra were captured at different time delays. Maximum enhancement in the neutral and ionic line intensities have been observed at 130 mJ laser energy. The neutral line of Pb at 368.34 nm reveals an enhancement factor of nearly 1.3, 1.6, and 2.3 at 0.3, 0.5, and 0.7 T, whereas the Pb ionic line at 424.49 nm shows enhancement factor of approximately 2.8 and 4.2 at 0.3 and 0.7 T. The magnetic field effects on various plasma parameters such as plasma temperature, electron number density, and emission line intensities have also been investigated. The plasma parameter “β” is found to be <1 in all the experimental conditions which signifies that the enhancement in the signal intensity is due to the plasma confinement. The increase in the emission signal intensity, number density as well as plasma temperature is observed with increasing laser energy and magnetic field. The spatial and temporal behavior reveals that the plasma temperature and electron number density decrease slowly in the applied magnetic field due to the deceleration of the plasma plume. The optimized conditions for the maximum plasma confinement and the emission intensity enhancement are observed at 130 mJ laser energy at 0.7 T magnetic field.
193 A New Syndrome: Phantogeusia-Induced Phantosmia
- Umar Ahmad, Alan R. Hirsch
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- Journal:
- CNS Spectrums / Volume 23 / Issue 1 / February 2018
- Published online by Cambridge University Press:
- 15 June 2018, p. 110
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Case Objective
While phantosmia-induced phantogeusia has been described (Ahmed, 20173), the reverse, phantogeusia-induced phantosmia, has not heretofore been described. Such a case is presented.
MethodsCase Study: A 39-yr-old left-handed (pathological) male, six years prior to presentation, noted a sudden onset of phantogeusia of roast cooking, pizza, fruit, strawberries, or a sour taste, and shortly thereafter he would develop unpleasant phantosmias which would sometimes combine with the ambient aroma. These would occur 3-10 times per week and would last for the duration of the phantogeusia, for as long as 1-2 hours. Occasionally the phantosmia would occur first and then induce the phantogeusia of asour taste.
ResultsAbnormalities in Neurologic examination: Mental status examination: Immediate recall: Digit span: 6 digits forward and 3 digits backwards. CN XI, X: Decreased gag bilaterally. Motor Examination: Drift: left pronator drift with right abductor digiti minimi sign and right cerebellar spooning. Gait Examination: Tandem Gait: unstable. Cerebellar Examination: Holmes Rebound Phenomena: bilaterally positive, left greater than the right. Sensory Examination: Ipswich Touch Test: decreased in left lower extremity. Temperature: decreased in left lower extremity. Rydel-Seiffer Vibratory Test: bilateral upper extremities 5, bilateral lower extremities 3. Reflexes: upper extremities 1+, absent lower extremities. Neuropsychiatric Examination: Go-No-Go Test: 6/6 (normal). Animal Fluency Test: 15 (normal). Clock Drawing Test: 3 (abnormal). Center for Neurologic Study Lability Scale: 16 (Pseudobulbar affect).
ConclusionClose connection of the tertiary smell and taste integration areas, where smell and taste converge, in the posterior orbitofrontal cortex, anterior to the insular taste cortex, and posterior to the granular orbitofrontal cortex may have allowed activation of memory engrams connecting these two (Rolls, 19944). Alternatively, electrical discharge from the primary taste area may have spread to involve the cortical representation of smell. Since the cortical area involved in the interpretation and hedonics of taste co-localize with the area involving olfactory hedonics, spread from one area to the other area may occur. As a result of electrical discharge (from an epileptiform focus) or as a result of well-connected and developed memory engrams with associated hedonics, phantom tastes may induce phantom smells. Alternatively, this may represent a distorted retronasal smell whereby the olfactory component of the gustatory hallucination causes a discharge of the olfactory epithelium (a pseudoretronasal smell).
Given the above, treatment of those with both phantosmia and phantogeusia may respond to treatment of phantogeusia alone. Under this construct, the phantosmia is the slave of the phantogeusia whereby management of the taste hallucination will thus eliminate the smell hallucination.
Funding AcknowledgementsSmell and Taste Treatment and Research Foundation.
Contributors
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- By Hamid M. Abdolmaleky, Cory Adamson, Paola Allavena, Dimitrios Anastasiou, Johanna Apfel, Surinder K. Batra, Mark E. Burkard, Amancio Carnero, Michael J. Clemens, Jeanette Gowen Cook, Isabel Dominguez, Jeremy S. Edwards, Wafik S. El-Deiry, Androulla Elia, Mohammad R. Eskandari, Aurora Esquela-Kerscher, Manel Esteller, Rob M. Ewing, Douglas V. Faller, Kristopher Frese, Xijin Ge, Giovanni Germano, Daniel A. Haber, William C. Hahn, Antoine Ho, Christine Iacobuzio-Donahue, Sergii Ivakhno, Prasad V. Jallepalli, Rosanne Jones, Sharyn Katz, Arnaud Krebs, Karl Krueger, Arthur W. Lambert, Adam Lerner, Holly Lewis, Jason W. Locasale, Giselle Y. López, Shyamala Maheswaran, Alberto Mantovani, José Ignacio Martín-Subero, Simon J. Morley, Oliver Müller, Kathleen R. Nevis, Sait Ozturk, Panagiotis Papageorgis, Jignesh R. Parikh, Steven M. Powell, Kimberly L. Raiford, Andrew M. Rankin, Patricia Reischmann, Simon Rosenfeld, Marc Samsky, Anthony Scott, Shantibhusan Senapati, Yashaswi Shrestha, Anurag Singh, Rakesh K. Singh, Gromoslaw A. Smolen, Sudhir Srivastava, Simon Tavaré, Sam Thiagalingam, László Tora, David Tuveson, Asad Umar, Matthew G. Vander Heiden, Cyrus Vaziri, Zhenghe John Wang, Kevin Webster, Chen Khuan Wong, Yu Xia, Hai Yan, Jian Yu, Lihua Yu, Min Yu, Lin Zhang, Jin-Rong Zhou
- Edited by Sam Thiagalingam
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- Book:
- Systems Biology of Cancer
- Published online:
- 05 April 2015
- Print publication:
- 09 April 2015, pp ix-xiv
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Investigation on the Frequency Allocation for Radio Astronomy at the L Band
- Z. Z. Abidin, R. Umar, Z. A. Ibrahim, Z. Rosli, K. Asanok, N. Gasiprong
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- Journal:
- Publications of the Astronomical Society of Australia / Volume 30 / 2013
- Published online by Cambridge University Press:
- 03 September 2013, e047
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In this paper, the frequency allocation reserved for radio astronomy in the L band set by the International Telecommunication Union (ITU), which is between 1400 and 1427 MHz, is reviewed. We argue that the nearby frequencies are still very important for radio astronomers on the ground by investigating radio objects (H i sources) around 1300–1500 MHz. The L-band window is separated into a group of four windows, namely 1400–1427 MHz (window A), 1380–1400 MHz (window B), 1350–1380 MHz (window C), and 1300–1350 MHz (window D). These windows are selected according to their redshifts from a rest frequency for hydrogen spectral line at 1420.4057 MHz. Radio objects up to z ≈ 0.1 or frequency down to 1300 MHz are examined. We argue that since window B has important radio objects within the four windows, this window should also be given to radio astronomy. They are galaxies, spiral galaxies, and galaxy clusters. This underlines the significance of window B for radio astronomers on the ground. By investigating the severeness of radio frequency interference (RFI) within these windows, we have determined that window B still has significant, consistent RFI. The main RFI sources in the four windows have also been identified. We also found that the Department of Civil Aviation of Malaysia is assigned a frequency range of 1215–1427 MHz, which is transmitted within the four windows and inside the protected frequency for radio astronomy. We also investigated the RFI in the four windows on proposed sites of future radio astronomy observatories in Malaysia and Thailand and found the two best sites as Universiti Pendidikan Sultan Idris (UPSI) and Ubon Ratchathani, respectively. It has also been determined that RFI in window B increases with population density.