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Search Results: 1 - 10 of 87746 matches for " Malka I "
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Highly biocompatible, nanocrystalline hydroxyapatite synthesized in a solvothermal process driven by high energy density microwave radiation
Smolen D,Chudoba T,Malka I,Kedzierska A
International Journal of Nanomedicine , 2013,
Abstract: Dariusz Smolen1, Tadeusz Chudoba1, Iwona Malka1, Aleksandra Kedzierska1, Witold Lojkowski1, Wojciech Swieszkowski2, Krzysztof Jan Kurzydlowski2, Malgorzata Kolodziejczyk-Mierzynska3, Malgorzata Lewandowska-Szumiel31Polish Academy of Science, Institute of High Pressure Physics, Warsaw, Poland; 2Faculty of Materials Engineering, Warsaw University of Technology, Warsaw, Poland; 3Department of Histology and Embryology, Center of Biostructure Research, Medical University of Warsaw, Warsaw, PolandAbstract: A microwave, solvothermal synthesis of highly biocompatible hydroxyapatite (HAp) nanopowder was developed. The process was conducted in a microwave radiation field having a high energy density of 5 W/mL and over a time less than 2 minutes. The sample measurements included: powder X-ray diffraction, density, specific surface area, and chemical composition. The morphology and structure were investigated by scanning electron microscopy as well as transmission electron microscopy (TEM). The thermal behavior analysis was conducted using a simultaneous thermal analysis technique coupled with quadruple mass spectrometry. Additionally, Fourier transform infrared spectroscopy tests of heated samples were performed. A degradation test and a biocompatibility study in vitro using human osteoblast cells were also conducted. The developed method enables the synthesis of pure, fully crystalline hexagonal HAp nanopowder with a specific surface area close to 240 m2/g and a Ca/P molar ratio equal to 1.57. TEM measurements showed that this method results in particles with an average grain size below 6 nm. A 28-day degradation test conducted according to the ISO standard indicated a 22% loss of initial weight and a calcium ion concentration at 200 μmol/dm3 in the tris(hydroxymethyl)aminomethane hydrochloride test solution. The cytocompatibility of the obtained material was confirmed in a culture of human bone derived cells, both in an indirect test using the material extract, and in direct contact. A quantitative analysis was based on the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide. Viability assay as well as on DNA content measurements in the PicoGreen test. Indirect observations were performed at one point in time according to the ISO standard for in vitro cytotoxicity (ie, after 24 hours of cell exposure to the extracts). The direct contact tests were completed at three time points: after 24 hours, on day 7, and on day 14 of a culture in an osteogenic medium. All of the tests revealed good tolerance of cells toward the material; this was also sh
Children’s resilience, loneliness and hope: The Positive Psychology perspectives
Malka Margalit
Revista de Psicología y Educación , 2012,
Abstract: In this paper, we shall present theoretical approaches and new research on the implications of positive psychology for understanding children’s resilience, happiness, and hope. Young people keep contacts with family, friends, “friends of friends” and total strangers. Social networking has been growing in richness, enabling diverse routes to challenge the social isolation. Yet, many children and adolescents continue to feel alone even among friends. Our responsibility is to sensitize families and schools to the children’s distress and to promote innovative research as well as prevention and intervention programs, among others. In this paper, we shall discuss the predictive roles of individual and systemic risk and protective factors (such as family support and schools’ empowerment) within the positive psychology approach, in order to provide clarification of developmental trends.
Laser Plasma Accelerators
V. Malka
Physics , 2011,
Abstract: Research activities on laser plasma accelerators are paved by many significant breakthroughs. This review article provides an opportunity to show the incredible evolution of this field of research which has, in record time, allowed physicists to produce high quality electron beams at the GeV level using compact laser systems. I will show the scientific path that led us to explore different injection schemes and to produce stable, high peak current and high quality electron beams with control of the charge, of the relative energy spread, and of the electron energy.
Amplified short-wavelength light scattered by relativistic electrons in the laser-induced optical lattice
I. A. Andriyash,V. T. Tikhonchuk,V. Malka,E. d'Humières,Ph. Balcou
Physics , 2014,
Abstract: The scheme of the XUV/X-ray free electron laser based on the optical undulator created by two overlapped transverse laser beams is analyzed. A kinetic theoretical description and an ad hoc numerical model are developed to account for the finite energy spread, angular divergence and the spectral properties of the electron beam in the optical lattice. The theoretical findings are compared to the results of the one- and three-dimensional numerical modeling with the spectral free electron laser code PLARES.
High Degree Atrioventricular Block Complicated Cardiac Sarcoidosis: Case Report  [PDF]
Malka Yahalom, Ofir Koren, Yoav Turgeman
World Journal of Cardiovascular Surgery (WJCS) , 2018, DOI: 10.4236/wjcs.2018.89015
Abstract: Cardiac Sarcoidosis (CS) is a rare and deceptive disease affecting young adults with catastrophic results including life threatening arrhythmia, congestive heart failure and even sudden death as the initial presentation. CS has been linked to a significant high morbidity & mortality. We present two patients: The first patient with an initial cardiac event that led us to a diagnosis of Pulmonary and Cardiac Sarcoidosis. A second patient, who was diagnosed initially with pulmonary Sarcoidosis, presented with a severe heart conduction abnormality. Both patients were successfully treated with permanent pacemakers. The dual purpose of our study is first to emphasize the importance of follow up on patients with Non-Cardiac Sarcoidosis for cardiac involvement and secondly to increase awareness of CS as part of a differential diagnosis among young adults with unexplained arrhythmia.
Success rate of IR midazolam sedation in combination with C-CLAD in pediatric dental patients—a prospective observational study
Malka Ashkenazi,Anat Baniel
PeerJ , 2015, DOI: 10.7717/peerj.254
Abstract: Objective. To evaluate the success rate of intra-rectal (IR) midazolam in combination with nitrous oxide/oxygen (N2O) sedation in young uncooperative dental patients when the local anesthesia is delivered by a computerized controlled local anesthetic delivery (C-CLAD).
The Quantum sl2-Invariant of a Family of Knots  [PDF]
Abdul Rauf Nizami, Mobeen Munir, Malka Shah Bano
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.51008
Abstract:

We give a general formula of the quantum sl2-invariant of a family of braid knots. To compute the quantum invariant of the links we use the Lie algebra g=sl2 in its standard two-dimensional representation. We also recover the Jones polynomial of these knots as a special case of this quantum invariant.

Optimization of the A Constant for the SRK/T Formula  [PDF]
John C. Merriam, Eva Nong, Lei Zheng, Malka Stohl
Open Journal of Ophthalmology (OJOph) , 2015, DOI: 10.4236/ojoph.2015.53017
Abstract: Purpose: To evaluate the effect of axial length (AL) and the average preoperative keratometry (K) on the A constant in the SRK/T formula. Methods: The retrospective, comparative case series includes 635 eyes from 407 cataract patients from Columbia University Medical Center from January 2006 to August 2010, operated by a single surgeon using a temporal incision and the Acrysof SN60WF IOL (Alcon Laboratories, TX). Using the postoperative manifest refraction and biometry data, we calculated the precise A constant (Ap) necessary to yield the postoperative spherical equivalent for each eye. To optimize the A constant, we developed three regression models (linear, quadratic, and categorical in 7 AL groups) to relate these precise A constants to AL and K. We verified our method with another series of 45 eyes for which we calculated mean errors (defined as the difference between the spherical equivalent of the postoperative refraction and the predicted postoperative refraction) using the optimized and manufacturer’s suggested A constants. Results: There is a statistically significant relationship between AL (P < 0.001), K (P < 0.001) and the A constant. Ap increased as AL increased and as K decreased. In the validation data set, optimizing the A constant reduced mean errors from 0.50 D to 0.25 D and also reduced hyperopic refractive outcomes. Conclusions: The A constant for longer eyes with flatter corneas is larger than the A constant for shorter eyes with steeper corneas. Optimizing A constants using both AL and K improved the predictability of refractive outcomes without modification to the SRK/T formula.
Chest Irradiation Associated Cardio-Vascular Disease  [PDF]
Malka Yahalom, Ehud Rozner, Menachem Nahir, Lev Bloch, Yoav Turgeman
World Journal of Cardiovascular Diseases (WJCD) , 2016, DOI: 10.4236/wjcd.2016.66019
Abstract: Background: The heart and great vessels were once thought to be relatively resistant to the damaging effect of radiation therapy. There is now clear evidence that thoracic irradiation may cause acute inflammation and progressive fibrosis of different structures, including the heart valves, the myocardium and the pericardium, the coronary arteries and the conduction system. As new therapies have improved survival, many patients with cancer (mostly Hodgkin’s disease and breast cancer) are now at risk of cardiovascular (CV) complications following radiation therapy. Objectives: To raise awareness of CV complications following chest irradiation. Method: We present 5 patients that we treated during a short period of time (between June 2013 (6/2013) and February 2015 (2/2016)), who suffered CV involvement that needed therapy, following chest irradiation. Conclusions: Patients after chest irradiation should be followed periodically, in order to diagnose and treat CV complications, in time.
Highly biocompatible, nanocrystalline hydroxyapatite synthesized in a solvothermal process driven by high energy density microwave radiation
Smolen D, Chudoba T, Malka I, Kedzierska A, Lojkowski W, Swieszkowski W, Kurzydlowski KJ, Kolodziejczyk-Mierzynska M, Lewandowska-Szumiel M
International Journal of Nanomedicine , 2013, DOI: http://dx.doi.org/10.2147/IJN.S39299
Abstract: hly biocompatible, nanocrystalline hydroxyapatite synthesized in a solvothermal process driven by high energy density microwave radiation Original Research (1184) Total Article Views Authors: Smolen D, Chudoba T, Malka I, Kedzierska A, Lojkowski W, Swieszkowski W, Kurzydlowski KJ, Kolodziejczyk-Mierzynska M, Lewandowska-Szumiel M Published Date February 2013 Volume 2013:8 Pages 653 - 668 DOI: http://dx.doi.org/10.2147/IJN.S39299 Received: 18 October 2012 Accepted: 28 November 2012 Published: 12 February 2013 Dariusz Smolen1, Tadeusz Chudoba1, Iwona Malka1, Aleksandra Kedzierska1, Witold Lojkowski1, Wojciech Swieszkowski2, Krzysztof Jan Kurzydlowski2, Malgorzata Kolodziejczyk-Mierzynska3, Malgorzata Lewandowska-Szumiel3 1Polish Academy of Science, Institute of High Pressure Physics, Warsaw, Poland; 2Faculty of Materials Engineering, Warsaw University of Technology, Warsaw, Poland; 3Department of Histology and Embryology, Center of Biostructure Research, Medical University of Warsaw, Warsaw, Poland Abstract: A microwave, solvothermal synthesis of highly biocompatible hydroxyapatite (HAp) nanopowder was developed. The process was conducted in a microwave radiation field having a high energy density of 5 W/mL and over a time less than 2 minutes. The sample measurements included: powder X-ray diffraction, density, specific surface area, and chemical composition. The morphology and structure were investigated by scanning electron microscopy as well as transmission electron microscopy (TEM). The thermal behavior analysis was conducted using a simultaneous thermal analysis technique coupled with quadruple mass spectrometry. Additionally, Fourier transform infrared spectroscopy tests of heated samples were performed. A degradation test and a biocompatibility study in vitro using human osteoblast cells were also conducted. The developed method enables the synthesis of pure, fully crystalline hexagonal HAp nanopowder with a specific surface area close to 240 m2/g and a Ca/P molar ratio equal to 1.57. TEM measurements showed that this method results in particles with an average grain size below 6 nm. A 28-day degradation test conducted according to the ISO standard indicated a 22% loss of initial weight and a calcium ion concentration at 200 μmol/dm3 in the tris(hydroxymethyl)aminomethane hydrochloride test solution. The cytocompatibility of the obtained material was confirmed in a culture of human bone derived cells, both in an indirect test using the material extract, and in direct contact. A quantitative analysis was based on the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide. Viability assay as well as on DNA content measurements in the PicoGreen test. Indirect observations were performed at one point in time according to the ISO standard for in vitro cytotoxicity (ie, after 24 hours of cell exposure to the extracts). The direct contact tests were completed at three time points: after 24 hours, on day 7, and on day 14 of a cultu
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