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Zode GS, Sharma AB, Lin X, Searby CC, Bugge K, Kim GH, Clark AF, Sheffield VC. Ocular-specific ER stress reduction rescues glaucoma in murine glucocorticoid-induced glaucoma. J Clin Invest 2014; 124:1956-65. [PMID: 24691439 DOI: 10.1172/jci69774] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 01/30/2014] [Indexed: 12/22/2022] Open
Abstract
Administration of glucocorticoids induces ocular hypertension in some patients. If untreated, these patients can develop a secondary glaucoma that resembles primary open-angle glaucoma (POAG). The underlying pathology of glucocorticoid-induced glaucoma is not fully understood, due in part to lack of an appropriate animal model. Here, we developed a murine model of glucocorticoid-induced glaucoma that exhibits glaucoma features that are observed in patients. Treatment of WT mice with topical ocular 0.1% dexamethasone led to elevation of intraocular pressure (IOP), functional and structural loss of retinal ganglion cells, and axonal degeneration, resembling glucocorticoid-induced glaucoma in human patients. Furthermore, dexamethasone-induced ocular hypertension was associated with chronic ER stress of the trabecular meshwork (TM). Similar to patients, withdrawal of dexamethasone treatment reduced elevated IOP and ER stress in this animal model. Dexamethasone induced the transcriptional factor CHOP, a marker for chronic ER stress, in the anterior segment tissues, and Chop deletion reduced ER stress in these tissues and prevented dexamethasone-induced ocular hypertension. Furthermore, reduction of ER stress in the TM with sodium 4-phenylbutyrate prevented dexamethasone-induced ocular hypertension in WT mice. Our data indicate that ER stress contributes to glucocorticoid-induced ocular hypertension and suggest that reducing ER stress has potential as a therapeutic strategy for treating glucocorticoid-induced glaucoma.
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Sharma AB, Sharma SK, Sharma M, Pandey RK, Reddy DS. Structural and optical investigation of semiconductor CdSe/CdS core-shell quantum dot thin films. Spectrochim Acta A Mol Biomol Spectrosc 2009; 72:285-290. [PMID: 19038577 DOI: 10.1016/j.saa.2008.09.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 09/02/2008] [Accepted: 09/26/2008] [Indexed: 05/27/2023]
Abstract
Highly luminescent CdSe/CdS core-shell nanocrystals have been assembled on indium tin oxide (ITO) coated glass substrates using a wet synthesis route. The physical properties of the quantum dots (QD) have been investigated using X-ray diffraction, transmission electron microscopy and optical absorption spectroscopy techniques. These quantum dots showed a strong enhancement in the near band edge absorption. The in situ luminescence behavior has been interpreted in the light of the quantum confinement effect and induced strain in the core-shell structure.
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Affiliation(s)
- A B Sharma
- Department of Physics, Barkatullah University, Bhopal, M.P. 462026, India
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Sharma M, Gupta D, Kaushik D, Sharma AB, Pandey RK. Highly luminescent inverted ZnS/CdS core/shell quantum dots. J Nanosci Nanotechnol 2008; 8:3949-3954. [PMID: 19049156 DOI: 10.1166/jnn.2008.195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Synthesis of highly luminescent and monochromatic inverted core-shell structures utilizing ZnS/CdS quantum dots (QDs) has been investigated. The core/shell quantum dots have been characterized using grazing angle X-ray diffraction (XRD), Transmission electron microscopy, Optical absorption and luminescence spectroscopy. The results suggested that passivation of surface states along with an increased localization of electron and hole in CdS shell layer, give rise to increased monochromaticity with higher quantum yield. The possibility of using the inverted core-shell structure as an additional parameter for tuning the color of luminescence has also been discussed.
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Abstract
Self-organized cadmium sulfide quantum dots assembled using wet synthesis route on glass/ITO as well as Si(100) substrates have been investigated, using X-ray diffraction and transmission electron microscopy. The quantum dots have been shown to grow with a strong (111) orientation with narrow size distribution. Self-organized growth of the quantum dots was examined by high resolution imaging with an atomic force microscope. It is shown that increased self-organization is obtained on silicon substrate. The role of surfactant in imparting self-organization has been invoked to explain the observed morphological features. The as grown Q-dots exhibited size dependent blue shift in the absorption edge. The luminescence behavior of the quantum dots self-organized on glass/ITO as well as Si(100) substrate has also been examined. It is shown that substantial enhancement in luminescence yield is obtained for quantum dots grown on silicon substrate. A model to explain the observed luminescence enhancement has also been presented.
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Affiliation(s)
- Diksha Kaushik
- Materials Research Lab, Department of Physics, Bhopal University, Bhopal 462026, India
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Abstract
Primary tuberculosis of tongue is very rare with unusual presentation creating a diagnostic dilemma. We report a case of primary tuberculosis of tongue in a 49-year-old female patient. Tuberculosis was not suspected clinically and there was no other focus elsewhere in the body. Fine needle aspiration cytology was attempted but was inconclusive. The diagnosis was made after histopathological examination.
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Affiliation(s)
- A B Sharma
- Department of Pathology, Regional Institute of Medical Sciences, Imphal 795 004, Manipur, India.
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Kaushik D, Singh RR, Sharma AB, Gupta D, Sharma M, Pandey RK. Self-organized ZnSe quantum dots: synthesis and characterization. J Nanosci Nanotechnol 2008; 8:1502-1511. [PMID: 18468182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Self-organized ZnSe quantum dots (Q-ZnSe) were grown on indium tin oxide substrate using wet chemical technique without or in presence of copper and manganese dopants. The structural, morphological and luminescence properties of the as grown Q-dot films have been investigated, using X-ray diffraction, transmission electron microscopy, atomic force microscopy and optical and luminescence spectroscopy. Composition of the samples were analyzed using atomic absorption spectroscopy. The quantum dots have been shown to deposit in a compact, uniform and organized array on the indium tin oxide substrate. The size dependent blue shift in the experimentally determined absorption edge has been compared with the theoretical predictions based on the effective mass and tight binding approximations. It is shown that the experimentally determined absorption edges depart significantly from the theoretically calculated values. The photoluminescence properties of the undoped as well as doped Q-ZnSe have also been discussed.
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Affiliation(s)
- Diksha Kaushik
- Department of Physics, Bhopal University, Bhopal 462026, India
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Sharma AB, Barlow MA, Yang SH, Simpkins JW, Mallet RT. Pyruvate enhances neurological recovery following cardiopulmonary arrest and resuscitation. Resuscitation 2007; 76:108-19. [PMID: 17618729 PMCID: PMC2737333 DOI: 10.1016/j.resuscitation.2007.04.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 04/11/2007] [Accepted: 04/19/2007] [Indexed: 01/07/2023]
Abstract
PURPOSE Cerebral oxidative stress and metabolic dysfunction impede neurological recovery from cardiac arrest-resuscitation. Pyruvate, a potent antioxidant and energy-yielding fuel, has been shown to protect against oxidant- and ischemia-induced neuronal damage. This study tested whether acute pyruvate treatment during cardiopulmonary resuscitation can prevent neurological dysfunction and cerebral injury following cardiac arrest. METHODS Anesthetized, open-chest mongrel dogs underwent 5 min cardiac arrest, 5 min open-chest cardiac compression (OCCC), defibrillation and 3-day recovery. Pyruvate (n=9) or NaCl volume control (n=8) were given (0.125 mmol kg(-1) min(-1) i.v.) throughout OCCC and the first 55 min recovery. Sham dogs (n=6) underwent surgery and recovery without cardiac arrest-resuscitation. RESULTS Neurological deficit score (NDS), evaluated at 2-day recovery, was sharply increased in NaCl-treated dogs (10.3+/-3.5) versus shams (1.2+/-0.4), but pyruvate treatment mitigated neurological deficit (NDS=3.3+/-1.2; P<0.05 versus NaCl). Brain samples were taken for histological examination and evaluation of inflammation and cell death at 3-day recovery. Loss of pyramidal neurons in the hippocampal CA1 subregion was greater in the NaCl controls than in pyruvate-treated dogs (11.7+/-2.3% versus 4.3+/-1.2%; P<0.05). Cardiac arrest increased caspase-3 activity, matrix metalloproteinase activity, and DNA fragmentation in the CA1 subregion; pyruvate prevented caspase-3 activation and DNA fragmentation, and suppressed matrix metalloproteinase activity. CONCLUSION Intravenous pyruvate therapy during cardiopulmonary resuscitation prevents initial oxidative stress and neuronal injury and enhances neurological recovery from cardiac arrest.
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Affiliation(s)
- Arti B. Sharma
- Department of Integrative Physiology, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Matthew A. Barlow
- Department of Integrative Physiology, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Shao-Hua Yang
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - James W. Simpkins
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Robert T. Mallet
- Department of Integrative Physiology, University of North Texas Health Science Center, Fort Worth, Texas, USA
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Abstract
Oxidative stress during cardiac arrest may inactivate myocardial enzymes and thereby exacerbate ischemic derangements of myocardial metabolism. This study examined the impact of cardiac arrest on left ventricular enzymes. Beagles were subjected to 5 min of cardiac arrest and 5 min of open-chest cardiac compressions (OCCC) before epicardial direct current countershocks were applied to restore sinus rhythm. Glutathione/glutathione disulfide redox state (GSH/GSSG) and a panel of enzyme activities were measured in snap-frozen left ventricle. To test whether oxidative stress during arrest inactivated the enzymes, metabolic (pyruvate) or pharmacological (N-acetyl-l-cysteine) antioxidants were infused intravenously for 30 min before arrest. During cardiac arrest, activities of phosphofructokinase, citrate synthase, aconitase, malate dehydrogenase, creatine kinase, glucose-6-phosphate dehydrogenase, and glutathione reductase fell by 56, 81, 55, 34, 42, 55, and 45%, respectively, coincident with 50% decline in GSH/GSSG. OCCC effected full recovery of glutathione reductase and partial recovery of citrate synthase and aconitase, in parallel with GSH/GSSG. Phosphofructokinase, malate dehydrogenase, creatine kinase, and glucose-6-phosphate dehydrogenase recovered only after cardioversion. Antioxidant pretreatments augmented phosphofructokinase, aconitase, and malate dehydrogenase activities before arrest and enhanced these activities, as well as those of citrate synthase and glucose-6-phosphate dehydrogenase, during arrest. In conclusion, cardiac arrest reversibly inactivates several important myocardial metabolic enzymes. Antioxidant protection of these enzymes implicates oxidative stress as a principal mechanism of enzyme inactivation during arrest.
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Affiliation(s)
- Arti B Sharma
- Dept. of Integrative Physiology, Univ. of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107-2699, USA
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Sharma AB, Knott EM, Bi J, Martinez RR, Sun J, Mallet RT. Pyruvate improves cardiac electromechanical and metabolic recovery from cardiopulmonary arrest and resuscitation. Resuscitation 2005; 66:71-81. [PMID: 15993732 DOI: 10.1016/j.resuscitation.2004.12.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Revised: 12/05/2004] [Accepted: 12/05/2004] [Indexed: 12/20/2022]
Abstract
Severe depletion of myocardial energy and antioxidant resources during cardiac arrest culminates in electromechanical dysfunction following recovery of spontaneous circulation (ROSC). A metabolic fuel and natural antioxidant, pyruvate augments myocardial energy and antioxidant redox states in parallel with its enhancement of contractile performance of stunned and oxidant-challenged hearts. This study tested whether pyruvate improves post-arrest cardiac function and metabolism. Beagles were subjected to 5 min cardiac arrest and 5 min open-chest cardiac compression (OCCC: 80 compressions min(-1); aortic pressure 60-70 mmHg), then epicardial dc countershocks (5-10 J) were applied to restore sinus rhythm. Pyruvate was infused i.v. throughout OCCC and the first 25 min ROSC to a steady-state arterial concentration of 3.6+/-0.2 mM. Control experiments received NaCl infusions. Phosphocreatine phosphorylation potential (approximately PCr) and glutathione/glutathione disulfide ratio (GSH/GSSG), measured in snap-frozen left ventricle, indexed energy and antioxidant redox states, respectively. In control experiments, left ventricular pressure development, dP/dt and carotid flow initially recovered upon defibrillation, but then fell 40-50% by 3 h ROSC. ST segment displacement in lead II ECG persisted throughout ROSC. Approximately PCr collapsed and GSH/GSSG fell 61% during arrest. Both variables recovered partially during OCCC and completely during ROSC. Pyruvate temporarily increased approximately PCr and GSH/GSSG during OCCC and the first 25 min ROSC and enhanced pressure development, dP/dt and carotid flow at 15-25 min ROSC. Contractile function stabilized and ECG normalized at 2-3 h ROSC, despite post-infusion pyruvate clearance and waning of its metabolic benefits. In conclusion, intravenous pyruvate therapy increases energy reserves and antioxidant defenses of resuscitated myocardium. These temporary metabolic improvements support post-arrest recovery of cardiac electromechanical performance.
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Affiliation(s)
- Arti B Sharma
- Department of Integrative Physiology, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107-2699, USA
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Abstract
Pyruvate, a natural metabolic fuel and antioxidant in myocardium and other tissues, exerts a variety of cardioprotective actions when provided at supraphysiological concentrations. Pyruvate increases cardiac contractile performance and myocardial energy state, bolsters endogenous antioxidant systems, and protects myocardium from ischemia-reperfusion injury and oxidant stress. This article reviews and discusses basic and clinically oriented research conducted over the last several years that has yielded fundamental information on pyruvate's inotropic and cardioprotective mechanisms. Particular attention is placed on pyruvate's enhancement of sarcoplasmic reticular Ca2+ transport, its antioxidant properties, and its ability to mitigate reversible and irreversible myocardial injury. These research efforts are establishing the essential foundation for clinical application of pyruvate therapy in numerous settings including cardiopulmonary bypass surgery, cardiopulmonary resuscitation, myocardial stunning, and cardiac failure.
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Affiliation(s)
- Robert T Mallet
- Department of Integrative Physiology, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107-2699, USA.
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Knott EM, Ryou MG, Sun J, Heymann A, Sharma AB, Lei Y, Baig M, Mallet RT, Olivencia-Yurvati AH. Pyruvate-fortified cardioplegia suppresses oxidative stress and enhances phosphorylation potential of arrested myocardium. Am J Physiol Heart Circ Physiol 2005; 289:H1123-30. [PMID: 15908464 DOI: 10.1152/ajpheart.00322.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cardioplegic arrest for bypass surgery imposes global ischemia on the myocardium, which generates oxyradicals and depletes myocardial high-energy phosphates. The glycolytic metabolite pyruvate, but not its reduced congener lactate, increases phosphorylation potential and detoxifies oxyradicals in ischemic and postischemic myocardium. This study tested the hypothesis that pyruvate mitigates oxidative stress and preserves the energy state in cardioplegically arrested myocardium. In situ swine hearts were arrested for 60 min with a 4:1 mixture of blood and crystalloid cardioplegia solution containing 188 mM glucose alone (control) or with additional 23.8 mM lactate or 23.8 mM pyruvate and then reperfused for 3 min with cardioplegia-free blood. Glutathione (GSH), glutathione disulfide (GSSG), and energy metabolites [phosphocreatine (PCr), creatine (Cr), P(i)] were measured in myocardium, which was snap frozen at 45 min arrest and 3 min reperfusion to determine antioxidant GSH redox state (GSH/GSSG) and PCr phosphorylation potential {[PCr]/([Cr][P(i)])}. Coronary sinus 8-isoprostane indexed oxidative stress. Pyruvate cardioplegia lowered 8-isoprostane release approximately 40% during arrest versus control and lactate cardioplegia. Lactate and pyruvate cardioplegia dampened (P < 0.05 vs. control) the surge of 8-isoprostane release following reperfusion. Pyruvate doubled GSH/GSSG versus lactate cardioplegia during arrest, but GSH/GSSG fell in all three groups after reperfusion. Myocardial [PCr]/([Cr][P(i)]) was maintained in all three groups during arrest. Pyruvate cardioplegia doubled [PCr]/([Cr][P(i)]) versus control and lactate cardioplegia after reperfusion. Pyruvate cardioplegia mitigates oxidative stress during cardioplegic arrest and enhances myocardial energy state on reperfusion.
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Affiliation(s)
- E Marty Knott
- Department of Integrative Physiology, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107-2699, USA
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Zhang JG, Picchi G, Sharma AB. Design of efficient all-optical code-division multiplexing systems supporting multiple-bit-rate and equal-bit-rate transmissions. Appl Opt 2000; 39:2264-2277. [PMID: 18345133 DOI: 10.1364/ao.39.002264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We present the design of efficient all-optical code-division multiplexing (AOCDM) systems that can transmit multiple-bit-rate (MBR) data signals over a common optical fiber. This is achieved when the proposed strict optical orthogonal code (OOC) of autocorrelation and cross-correlation constraints of 1 are used but without performance degradation compared with the use of conventional OOC. We describe the design of various strict OOC's by employing the useful concept of slot distances, and methods of code construction are also presented. Moreover, we give the principle of MBR data transmissions in an AOCDM system. It is shown that AOCDM systems using the proposed OOC can effectively transmit multiuser MBR and equal-bit-rate (EBR) data with no increase of system complexity. In principle, optimal strict OOC's need the same or a slightly larger system bandwidth compared with optimal conventional OOC's for EBR operation, whereas the former can require a smaller system bandwidth and have a better system performance than the latter for MBR transmissions. A new, to our knowledge, family of strict OOC's is also introduced, whose code words can have nonconstant weights to support multiuser communications with different transmission quality. Furthermore, we design low-cost AOCDM transmitters that are based on an efficient gain-switching scheme that does not require an electro-optic intensity modulator to on-off modulate an optical clock pulse stream at each transmitter. The basic operation principle is also experimentally demonstrated.
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Anthony JP, Foster RD, Sharma AB, Kearns GJ, Hoffman WY, Pogrel MA. Reconstruction of a complex midfacial defect with the folded fibular free flap and osseointegrated implants. Ann Plast Surg 1996; 37:204-10. [PMID: 8863985 DOI: 10.1097/00000637-199608000-00017] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Refinements in microsurgical techniques, plate fixation, and osseointegration have changed the conceptual approach to midface reconstruction. Free tissue transfer has emerged as the ideal method of reconstructing complex midfacial defects. Single-stage bony restoration of the palate and orbital rim using the folded fibular osteocutaneous free flap is described. The fibular free flap is our first choice for reconstructing complex midfacial defects. The thin, soft, pliable tissue is ideal for intraoral and palatal reconstructions. The bone can be tailored precisely to fit any desired shape, and forms a sturdy support for both orbital and dental prostheses. With a single flap, rapid and reliable restoration of midfacial appearance, orbital support, and palatal function can be achieved.
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Affiliation(s)
- J P Anthony
- Division of Plastic and Reconstructive Surgery, University of California at San Francisco 94115-1632, USA
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Debnath K, Singh TD, Sharma AB, Devi SS, Singh AS. Sex cord tumour with annular tubules--a case report. INDIAN J PATHOL MICR 1994; 37:331-3. [PMID: 7814067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- K Debnath
- Department of Pathology, Regional Medical College, Imphal, Manipur
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Perrott DH, Smith RA, Sharma AB, McArdle L. Maxillary and mandibular reconstruction in preparation for endosseous implants. J Calif Dent Assoc 1993; 21:39-43. [PMID: 7504094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Bony and soft tissue deficiencies can deter esthetic, functional and prosthetic rehabilitation. Modern surgical techniques using bone or composite grafts to reconstruct or augment implant sites are reviewed.
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Affiliation(s)
- D H Perrott
- UCSF School of Dentistry, San Francisco, CA 94143-0440
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Saijonmaa J, Sharma AB, Halme SJ. Selective excitation of parabolic-index optical fibers by Gaussian beams. Appl Opt 1980; 19:2442-2452. [PMID: 20234433 DOI: 10.1364/ao.19.002442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Excitation coefficients of the guided modes of a parabolic-index optical fiber by narrow input Gaussian beams are calculated. The effects of beam offset, tilt, width, and wave-front curvature are examined. A wave-optical procedure for optimizing the input Gaussian beamwidth (to excite as few mode groups as possible) as a function of beam offset is presented and shown to be in agreement with a simple Fourier-optics optimization.
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Sharma AB, Halme SJ. Frequency response of optical fibers using a combination time-frequency domain technique. Appl Opt 1979; 18:1877-1879. [PMID: 20212567 DOI: 10.1364/ao.18.001877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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