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Real-time sono-elastography in the diagnosis of diffuse liver diseases

World Journal of Gastroenterology 2010年第14期16卷 1720-1726页

作者： Dan Ionut Gheonea Adrian S ǎftoiu Tudorel Ciurea Florin Gorunescu Sevastita Iordache gabriel lucian popescu Smaranda Belciug Marina Gorunescu Larisa Sǎndulescu Research Center of Gastroenterology and Hepatology University of Medicine and Pharmacy Craiova 200349 Romania Department of Biostatistics and Informatics University of Medicine and Pharmacy Craiova 200349 Romania IT Department University of Medicine and Pharmacy Craiova 200349 Romania Faculty of Mathematics of Computer Science University of Craiova Craiova 200585 Romania

AIM: To analyze whether computer-enhanced dynamic analysis of elastography movies is able to better characterize and differentiate between different degrees of liver fibrosis. METHODS: The study design was prospective. A total of 132 consecutive patients with chronic liver diseases and healthy volunteers were examined by transabdominal ultrasound elastography. All examinations were done by two ***: Due to the limitations of the method, we obtained high-quality elastography information in only 73.48% of the patients. The κ-means clustering method was applied to assess the inter-observer diagnosis varia- bility, which showed good variability values in accordance with the experience of ultrasound examination of every observer. Cohen’sκ test indicated a moderate agreement between the study observers (κ = 0.4728). Furthermore, we compared the way the two observers clustered the patients, using the test for comparing two proportions (t value, two-sided test). There was no statistically significant difference between the two physicians, regardless of the patients’ real status. CONCLUSION: Transabdominal real-time elastography is certainly a very useful method in depicting liver hard- ness, although it is incompletely tested in large multicenter studies.

关键词： Elastography Ultrasonography Liver steato- sis Viral hepatitis Liver cirrhosis

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Wolf phase tomography(WPT) of transparent structures using partially coherent illumination

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Light(Science & Applications) 2020年第1期9卷 656-664页

作者： Xi Chen Mikhail E.Kandel Chenfei Hu Young Jae Lee gabriel popescu Quantitative Light Imaging Laboratory Beckman Institute for Advanced Science and TechnologyDepartment of Electrical and Computer EngineeringUniversity of Illinois at Urbana-ChampaignUrbanaIL 61801USA

In 1969,Emil Wolf proposed diffraction tomography using coherent holographic imaging to extract 3D information from transparent,inhomogeneous *** the same era,the Wolf equations were first used to describe the propagation correlations associated with partially coherent *** these two concepts,we present Wolf phase tomography(WPT),which is a method for performing diffraction tomography using partially coherent *** reconstruction works directly in the space-time domain,without the need for Fourier transformation,and decouples the refractive index(RI)distribution from the thickness of the *** demonstrate the WPT principle using the data acquired by a quantitative-phase-imaging method that upgrades an existing phase-contrast microscope by introducing controlled phase shifts between the incident and scattered *** illumination field in WPT is partially spatially coherent(emerging from a ring-shaped pupil function)and of low temporal coherence(white light),and as such,it is well suited for the Wolf *** three intensity measurements corresponding to different phase-contrast frames,the 3D RI distribution is obtained immediately by computing the Laplacian and second time derivative of the measured complex correlation *** validate WPT with measurements of standard samples(microbeads),spermatozoa,and live neural *** high throughput and simplicity of this method enables the study of 3D,dynamic events in living cells across the entire multiwell plate,with an RI sensitivity on the order of 10^(−5).

关键词： WPT coherent illumination

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Gabor’s holography at sea

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Light(Science & Applications) 2019年第1期8卷 1004-1005页

作者： gabriel popescu Quantitative Light Imaging Laboratory Department of Electrical and Computer EngineeringBeckman Institute for Advanced Science and TechnologyUniversity of Illinois at Urbana-ChampaignUrbanaIL 61801USA

In 1948,predating lasers by more than a decade,Gabor proposed a“new microscopic principle”,which was initially aimed at correcting spherical aberrations in electron *** the method has not produced an impact in its originally intended field,it opened a new direction,known as holography,in ***’s technique allows one to store phase information by recording on film the intensity of a field emerging at a certain distance from an object.

关键词： Gabor recording initially

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二氧化钛气凝胶基质中金纳米粒子的光催化活性和结构(英文)

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催化学报 2013年第4期34卷 734-740页

作者： Zsolt PAP Andreea RADU Izabella Jolan HIDI Georgian MELINTE lucian DIAMANDESCU Traian popescu lucian BAIA Virginia DANCIU Monica BAIA Faculty of Chemistry and Chemical Engineering Babes‐Bolyai University 11 Arany Janos str. 400028 Cluj-Napoca Romanla Faculty of Physics Babes‐Bolyai University 1 MihaiL Kogalniceanu str. 400084 Cluj-Napoca Romania National Institute of Materials Physics P.O.Box MG-777125 Bucharest-Magurele Romania Institute for Interdisciplinary Research in Bio‐Nano‐Sciences Babes‐Bolyai University 42 Treboniu Laurian str 400271 Cluj-Napoca Romania

TiO2 -Au aerogels containing different amounts of gold nanoparticles of different sizes (5 and 16 nm) were successfully synthesized using a sol-gel procedure, and were tested for salicylic acid photodegradation under UV irradiation. The structure and morphology of the obtained materials were investigated using X-ray diffraction, transmission electron microscopy, and N2 adsorption-desorption measurements. UV-Vis spectroscopy was used to study the optical properties. The effects of the gold nanoparticles on the TiO2 crystallization process were twofold, as follows: (i) the number of crystallized zones was strongly related to the concentration of the gold nanoparticles, and (ii) the smaller gold particles increased the time taken for the crystallization of the samples. It was found that the noble metal-doped samples exhibited higher degradation rates compared with bare titania. It was found that the most active photocatalyst in each studied system was the sample with the highest concentration of gold nanoparticles. Additionally, the highest degradation rate value was obtained with the smallest Au nanoparticles (46.4 10-3 μmol/(L·s).

关键词： Nanomaterial Sol‐gel Titania Salicylic acid Photocatalytic performance

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GANscan:continuous scanning microscopy using deep learning deblurring

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Light(Science & Applications) 2022年第10期11卷 2378-2387页

作者： Michael John Fanous gabriel popescu Quantitative Light Imaging Laboratory Beckman Institute for Advanced Science and TechnologyUniversity of Illinois at Urbana-ChampaignUrbanaIL 61801USA Department of Bioengineering University of Illinois at Urbana-Champaign306 N.Wright StreetUrbanaIL 61801USA Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign306 N.Wright StreetUrbanaIL 61801USA

Most whole slide imaging(WSI)systems today rely on the"stop-and-stare"approach,where,at each field of view,the scanning stage is brought to a complete stop before the camera snaps a *** procedure ensures that each image is free of motion blur,which comes at the expense of long acquisition *** order to speed up the acquisition process,especially for large scanning areas,such as pathology slides,we developed an acquisition method in which the data is acquired continuously while the stage is moving at high *** generative adversarial networks(GANs),we demonstrate this ultra-fast imaging approach,referred to as GANscan,which restores sharp images from motion blurred *** allows us to complete image acquisitions at 30x the throughput of stop-and-stare *** method is implemented on a Zeiss Axio Observer Z1 microscope,requires no specialized hardware,and accomplishes successful reconstructions at stage speeds of up to 5000 μm/*** validate the proposed method by imaging H&E stained tissue *** method not only retrieves crisp images from fast,continuous scans,but also adjusts for defocusing that occurs during scanning within+/-5 μ*** a consumer GPU,the inference runs at<20 ms/image.

关键词： hardware continuous image

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Large-scale phase retrieval

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Light(Science & Applications) 2021年第10期10卷 1814-1815页

The coherent interaction between an electromagnetic field and a 3D weakly scattering medium results in a simple Fourier transform relationship between the object’s structure and the complex scattered *** a result,knowledge about the phase of the scattered field is necessary for solving this inverse problem with a unique ***,in applications,such as X-ray crystallography,typically one only has experimental access to the amplitude of the diffracted field,which results in ambiguities of the *** century-old challenge,known as“the phase problem”2 motivated the development of computational algorithms combined with a priori knowledge about the object of interest to limit the solution *** generally successful,this approach sometimes led to multiple solutions,i.e.,different inferred object structures for the same set of data:“Not all the guesses have been *** is clear,for example,from the following:Two different structures were predicted for the mineral bixbyite,one by ***,the other by *** is not known which,if either,is correct.”(Chapter 7 in ref.2).

关键词： phase scattered typically

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High-resolution impedance mapping using electrically activated quantitative phase imaging

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Light(Science & Applications) 2021年第2期10卷 186-196页

作者： Cristina Polonschii Mihaela Gheorghiu Sorin David Szilveszter Gáspár Sorin Melinte Hassaan Majeed Mikhail E.Kandel gabriel popescu Eugen Gheorghiu International Centre of Biodynamics 060101 BucharestRomania Institute of Information and Communication Technologies Electronics and Applied MathematicsUniversite Catholique de Louvain1348 Louvain-la-NeuveBelgium Quantitative Light Imaging Laboratory Beckman Institute for Advanced Science and TechnologyUniversity of Illinois at Urbana-ChampaignUrbanaIL 61801USA

Retrieving electrical impedance maps at the nanoscale rapidly via nondestructive inspection with a high signal-to-noise ratio is an unmet need,likely to impact various applications from biomedicine to energy *** this study,we develop a multimodal functional imaging instrument that is characterized by the dual capability of impedance mapping and phase quantitation,high spatial resolution,and low temporal *** achieve this,we advance a quantitative phase imaging system,referred to as epi-magnified image spatial spectrum microscopy combined with electrical actuation,to provide complementary maps of the optical path and electrical *** demonstrate our system with high-resolution maps of optical path differences and electrical impedance variations that can distinguish nanosized,semi-transparent,structured coatings involving two materials with relatively similar electrical *** map heterogeneous interfaces corresponding to an indium tin oxide layer exposed by holes with diameters as small as~550 nm in a titanium(dioxide)over-layer deposited on a glass *** show that electrical modulation during the phase imaging of a macro-electrode is decisive for retrieving electrical impedance distributions with submicron spatial resolution-and beyond the limitations of electrode-based technologies(surface or scanning technologies).The findings,which are substantiated by a theoretical model that fits the experimental data very well enable achieving electro-optical maps with high spatial and temporal *** virtues and limitations of the novel optoelectrochemical method that provides grounds for a wider range of electrically modulated optical methods for measuring the electric field locally are critically discussed.

关键词： impedance resolution phase

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The Risk Management of Companies From Timis County Involved in International Business

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Chinese Business Review 2011年第6期10卷 445-453页

作者： gabriel Bizoi Alexandra popescu West University of Timisoara Timisoara Romania

Rapid internationalization of economic activities following the Second World War has generated an unprecedented increase in international trade and capital flows. For example, only during 1963-1993, exports rose from 157 billion to 3.774 billion dollars. Also the flows of foreign direct investment （FDI） have grown exponentially. Although FDI flows are concentrated on developing countries, 80% being targeted towards 10 countries, capital flows towards the Third World have quadrupled only between 1990 and 1993. This trend towards a truly international economy influences also on how companies do business. International business environment provides many opportunities, as well as threats. Romanian companies need to align to this trend. In addition to identifying new opportunities to do business in foreign markets, they have to deal with specific risks, which they did not have to face when working internally. In this context, we consider necessary to launch an investigation, whose main objective would be analyzing the manner in which Romanian companies manage risks specific to international economic affairs. As the complexity of these businesses is great, and the majority of Romanian companies, in their attempt to internationalize, use classical forms of export-import, the analysis took into account only the export activity undertaken by Romanian companies. We mention that we did not take into account the determination of the exposure to these risks of the companies concerned, but an analysis of the management of those risks. For this analysis, data were collected based on the administration of a questionnaire, and these data were used to develop an econometric model analysis. The specific methods of risk analysis of specific export transactions are then interpreted using the GLOBE model.

关键词： risk management risk exposure probability commercial risks currency risk GLOBE model

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Adapted Metrics for a Modified Coulomb/Newton’s Potential

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Journal of High Energy Physics, Gravitation and Cosmology 2023年第4期9卷 1311-1355页

作者： lucian M. Ionescu Cristina-Liliana Pripoae gabriel Pripoae Department of Mathematics Illinois State University Normal IL USA Department of Applied Mathematics The Bucharest University of Economic Studies Bucharest Romania Faculty of Mathematics and Computer Science University of Bucharest Bucharest Romania

Modified Theories of Gravity include spin dependence in General Relativity, to account for additional sources of gravity instead of dark matter/energy approach. The spin-spin interaction is already included in the effective nuclear force potential, and theoretical considerations and experimental evidence hint to the hypothesis that Gravity originates from such an interaction, under an averaging process over spin directions. This invites to continue the line of theory initiated by Einstein and Cartan, based on tetrads and spin effects modeled by connections with torsion. As a first step in this direction, the article considers a new modified Coulomb/Newton Law accounting for the spin-spin interaction. The physical potential is geometrized through specific affine connections and specific semi-Riemannian metrics, canonically associated to it, acting on a manifold or at the level of its tangent bundle. Freely falling particles in these “toy Universes” are determined, showing an interesting behavior and unexpected patterns.

关键词： Modified Gravity Theory Spin Coulomb’s Law Newton’s Law Modified Coulomb’s Law Nuclear Force Adapted Connection Adapted Metric

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Optically monitoring and controlling nanoscale topography during semiconductor etching

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Light(Science & Applications) 2012年第1期1卷 41-46页

作者： Chris Edwards Amir Arbabi gabriel popescu Lynford L Goddard Department of Electrical and Computer Engineering University of Illinois at Urbana-ChampaignUrbanaIL 61801USA

We present epi-diffraction phase microscopy(epi-DPM)as a non-destructive optical method for monitoring semiconductor fabrication processes in real time and with nanometer level *** method uses a compact Mach–Zehnder interferometer to recover quantitative amplitude and phase maps of the field reflected by the *** low temporal noise of 0.6 nm per pixel at 8.93 frames per second enabled us to collect a three-dimensional movie showing the dynamics of wet etching and thereby accurately quantify non-uniformities in the etch rate both across the sample and over *** displaying a gray-scale digital image on the sample with a computer projector,we performed photochemical etching to define arrays of microlenses while simultaneously monitoring their etch profiles with epi-DPM.

关键词： microscopy nanoscale metrology photochemical etching quantitative phase imaging semiconductor process monitoring

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