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Anisotropic polarizability tensor of a dimer of nanospheres in the vicinity of a plane substrate

Anatoliy Pinchuk, George Schatz
2005 Nanotechnology  
We derive analytically the effective dipole polarizability tensor of a dimer of spheres located near a plane substrate. This is used to determine the extinction cross sections and other optical properties of the particles, and we use the results to study the experimentally observed red and blue shifts of the plasmon resonance of the dimer as a function of the distance between the particles or between the particles and the substrate. The results show that bringing the dimer towards the surface
more » ... wards the surface always leads to red shifted plasmon excitation. The plasmon resonance of the dimer may be red shifted or blue shifted as the particles are brought toward each other (at fixed distance from the surface) depending on the polarization. The size of the blue shift is smaller when the particles are close to the surface than when they are far away, but the red shifts are essentially unchanged.
doi:10.1088/0957-4484/16/10/039 pmid:20817997 fatcat:xoh2a7hwzjfztobhdoia5oipri

Understanding the Pathogenesis of Cytopathic and Noncytopathic Bovine Viral Diarrhea Virus Infection Using Proteomics [chapter]

Mais Ammari, Fiona McCarthy, Bindu Nanduri, George Pinchuk, Lesya Pinchuk
2012 Proteomic Applications in Biology  
studies used MS-based approaches to identify BVDV-induced cellular proteome changes, focusing on host immune changes, which are assessed by comparing protein profiles before and after BVDV infection (Pinchuk  ...  migration, anti-viral protection, sugar metabolism, and possibly the expression of the receptor for activated C kinase (RAC) were differentially expressed between the ncp and cp BVDV-infected monocytes (Pinchuk  ...  How to reference In order to correctly reference this scholarly work, feel free to copy and paste the following: Mais Ammari, Fiona McCarthy, Bindu Nanduri, George Pinchuk and Lesya Pinchuk (2012) .  ... 
doi:10.5772/29475 fatcat:dxxccf767vfsfeunfa7xgkr7cq

Epigenetic and PPI Targeted Libraries from Life Chemicals

Vasily Pinchuk, George Bondar, Olga Balabon
2019 Proceedings (MDPI)  
Herein, we report our novel epigenetic and PPI. [...]
doi:10.3390/proceedings2019022096 fatcat:mpmwkhvy25axllnd5ekxiujvsa

Multidimensional Boolean Patterns in Multi-omics Data [article]

George Golovko, Victor Reyes, Iryna Pinchuk, Yuriy Fofanov
2021 bioRxiv   pre-print
Motivation: Virtually all biological systems are governed by a set of complex relations between their components. Identification of relations within biological systems involves a rigorous search for patterns among variables/parameters. Two-dimensional (involving two variables) patterns are identified using correlation, covariation, and mutual information approaches. However, these approaches are not suited to identify more complicated multidimensional relations, which simultaneously include 3,
more » ... neously include 3, 4, and more variables. Results: We present a novel pattern-specific method to quantify the strength and estimate the statistical significance of multidimensional Boolean patterns in multiomics data. In contrast with dimensionality reduction and AI solutions, patterns identified by the proposed approach may provide a better background for meaningful mechanistic interpretation of the biological processes. Our preliminary analysis suggests that multidimensional patterns may dominate the landscape of multi-omics data, which is not surprising because complex interactions between components of biological systems are unlikely to be reduced to simple pairwise interactions.
doi:10.1101/2021.01.12.426358 fatcat:4xrxf2zy6vdrfpu7rokox3xw2i

Synthesis of Heterodimeric Sphere–Prism Nanostructures via Metastable Gold Supraspheres

Rafal Klajn, Anatoliy O. Pinchuk, George C. Schatz, Bartosz A. Grzybowski
2007 Angewandte Chemie  
Noble-metal nanoparticles of nonspherical shapes are interesting for their size-and shape-dependent optical properties [1] and for potential applications in hyperthermia of tumors, [2] pathogen detection, [3] and infrared-absorbing coatings. [4] Typically, such particles are grown in the presence of surfactants that stabilize certain crystallographic faces. For example, silver nanocubes can be prepared by stabilizing the Ag {100} faces with poly(4-vinylpyrrolidone) (PVP), [5] while gold
more » ... while gold nanorods are grown readily in the presence of cetyltrimethylammonium bromide (CTAB), which adsorbs selectively onto Au {100} faces. [6] Other nanostructures prepared by the latter method include gold hexagons, [7] [8] [9] gold triangles, [10] [11] [12] silver disks, [13] and several other shapes. [14] Recently, considerable effort has been devoted to the preparation of hybrid or dimer nanostructures, in which two (or more) domains of different shapes or material properties are permanently connected. [15] Such structures are usually made by epitaxial nucleation and growth on presynthesized nanoparticle seeds [16, 17] or by thermal decomposition of core-shell nanoparticles. [18] Herein, we describe a conceptually different route to a new class of nanoscopic heterodimers composed of spherical and polygonal domains. In our method, individual nanoparticles (NPs) are first assembled into metastable, supraspherical aggregates (SS, Figure 1 a, b) , and are then thermally decomposed into heterodimers (Figure 2 ). These composite particles are the result of temperature-induced coalescence of individual NPs accompanied by crystal nucleation. During this process, the relative sizes and dimensions of the SS and crystalline domains change controllably and give rise to pronounced changes in the particles optical response. In a typical experiment, gold supraspheres (SS, diameter 96 AE 13 nm [19] [20] [21] [22] [23] ) were prepared by rapid addition of 1,8octanedithiol dissolved in toluene (2.86 mm, 40 mL) to a stirred solution of gold nanoparticles (c Au = 1.0 mm, 1.75 mL) stabilized in toluene by excess didodecyldimethylammonium bromide (DDAB, 9 mm) and dodecylamine (DDA, 20 mm ; Figure 1 a, b) . The dithiol molecules displaced a portion of the loosely bound surfactant molecules and simultaneously crosslinked the NPs. The cross-linking continued until all NPs in solution were aggregated into spherical aggregates (SS), each composed of approximately 2500 NPs and with an average of 150 dithiol ligands per NP (for details of the growth mechanism, see reference [21] ). When the SS solution was heated at 95 8C, it remained blue for times t < 100 min, then rapidly turned gray; subsequently, its color slowly changed to green (t % 100-200 min, Figure 1 c). Corresponding UV/Vis spectra showed that at around t = 100 min, the intensity of the SS surface plasmon resonance (SPR) band at l max = 580 nm decreased dramatically, while a new, strong band at l max = 920 nm appeared Figure 1. a) Preparation of Au SS by controlled cross-linking of gold nanoparticles. The transformation is accompanied by a pronounced color change. b) SEM side view of several supraspheres resting on a surface of silicon. Scale bar = 100 nm. c) Color changes observed during thermal treatment of Au SS at 95 8C. d) UV/Vis spectra of the reaction mixture recorded at different heating times t. The spectra change abruptly at around 100 min.
doi:10.1002/ange.200702570 fatcat:kcmlz6w5ojechf5yezop3bakmu

Synthesis of Heterodimeric Sphere–Prism Nanostructures via Metastable Gold Supraspheres

Rafal Klajn, Anatoliy O. Pinchuk, George C. Schatz, Bartosz A. Grzybowski
2007 Angewandte Chemie International Edition  
Noble-metal nanoparticles of nonspherical shapes are interesting for their size-and shape-dependent optical properties [1] and for potential applications in hyperthermia of tumors, [2] pathogen detection, [3] and infrared-absorbing coatings. [4] Typically, such particles are grown in the presence of surfactants that stabilize certain crystallographic faces. For example, silver nanocubes can be prepared by stabilizing the Ag {100} faces with poly(4-vinylpyrrolidone) (PVP), [5] while gold
more » ... while gold nanorods are grown readily in the presence of cetyltrimethylammonium bromide (CTAB), which adsorbs selectively onto Au {100} faces. [6] Other nanostructures prepared by the latter method include gold hexagons, [7] [8] [9] gold triangles, [10] [11] [12] silver disks, [13] and several other shapes. [14] Recently, considerable effort has been devoted to the preparation of hybrid or dimer nanostructures, in which two (or more) domains of different shapes or material properties are permanently connected. [15] Such structures are usually made by epitaxial nucleation and growth on presynthesized nanoparticle seeds [16, 17] or by thermal decomposition of core-shell nanoparticles. [18] Herein, we describe a conceptually different route to a new class of nanoscopic heterodimers composed of spherical and polygonal domains. In our method, individual nanoparticles (NPs) are first assembled into metastable, supraspherical aggregates (SS, Figure 1 a, b) , and are then thermally decomposed into heterodimers (Figure 2 ). These composite particles are the result of temperature-induced coalescence of individual NPs accompanied by crystal nucleation. During this process, the relative sizes and dimensions of the SS and crystalline domains change controllably and give rise to pronounced changes in the particles optical response. In a typical experiment, gold supraspheres (SS, diameter 96 AE 13 nm [19] [20] [21] [22] [23] ) were prepared by rapid addition of 1,8octanedithiol dissolved in toluene (2.86 mm, 40 mL) to a stirred solution of gold nanoparticles (c Au = 1.0 mm, 1.75 mL) stabilized in toluene by excess didodecyldimethylammonium bromide (DDAB, 9 mm) and dodecylamine (DDA, 20 mm ; Figure 1 a, b) . The dithiol molecules displaced a portion of the loosely bound surfactant molecules and simultaneously crosslinked the NPs. The cross-linking continued until all NPs in solution were aggregated into spherical aggregates (SS), each composed of approximately 2500 NPs and with an average of 150 dithiol ligands per NP (for details of the growth mechanism, see reference [21] ). When the SS solution was heated at 95 8C, it remained blue for times t < 100 min, then rapidly turned gray; subsequently, its color slowly changed to green (t % 100-200 min, Figure 1 c). Corresponding UV/Vis spectra showed that at around t = 100 min, the intensity of the SS surface plasmon resonance (SPR) band at l max = 580 nm decreased dramatically, while a new, strong band at l max = 920 nm appeared Figure 1. a) Preparation of Au SS by controlled cross-linking of gold nanoparticles. The transformation is accompanied by a pronounced color change. b) SEM side view of several supraspheres resting on a surface of silicon. Scale bar = 100 nm. c) Color changes observed during thermal treatment of Au SS at 95 8C. d) UV/Vis spectra of the reaction mixture recorded at different heating times t. The spectra change abruptly at around 100 min.
doi:10.1002/anie.200702570 pmid:17902083 fatcat:g75seu54zrb7lbrurqxkmt7lzi

Potential Use of Transspinal Direct Current Stimulation For Cerebral Circulation Correction

George K Sirbiladze, Galina A Suslova, Dmitrij Ju Pinchuk, Timur K Sirbiladze
2017 Pediatrician (St Petersburg)  
(For citation: Sirbiladze GK, Suslova GA, Pinchuk DJ, Sirbiladze ТK. Potential use of transspinal direct current stimulation for cerebral circulation correction. Pediatrician (St.  ... 
doi:10.17816/ped8650-55 fatcat:ef4ilfqhmvgj3ls4iutvaolzga

Physical Characterization and Platelet Interactions under Shear Flows of a Novel Thermoset Polyisobutylene-based Co-polymer

Jawaad Sheriff, Thomas E. Claiborne, Phat L. Tran, Roshni Kothadia, Sheela George, Yasushi P. Kato, Leonard Pinchuk, Marvin J. Slepian, Danny Bluestein
2015 ACS Applied Materials and Interfaces  
Over the years, several polymers have been developed for use in prosthetic heart valves as alternatives to xenografts. However, most of these materials are beset with a variety of issues, including low material strength, biodegradation, high dynamic creep, calcification, and poor hemocompatibility. We studied the mechanical, surface, and flow-mediated thrombogenic response of poly(Styrene-coblock-4-vinylbenzocyclobutene)-polyIsoButylene-poly(Styrenecoblock-4-vinylbenzocylcobutene) (xSIBS), a
more » ... tene) (xSIBS), a thermoset version of the thermoplastic elastomeric polyolefin poly(Styrene-block-IsoButylene-block-Styrene) (SIBS), which has been shown to be resistant to in vivo hydrolysis, oxidation, and enzymolysis. Uniaxial tensile testing yielded an ultimate tensile strength of 35 MPa, 24.5 times greater than for SIBS. Surface analysis yielded a mean contact angle of 82.05° and surface roughness of 144 nm, which was greater than for poly(εcaprolactone) (PCL) and poly(methyl methacrylate) (PMMA). However, the change in platelet activation state, a predictor of thrombogenicity, was not significantly different from PCL and PMMA after fluid exposure to 1 dyne/cm 2 and 20 dyne/cm 2 . In addition, the number of adherent platelets after 10 dyne/cm 2 flow exposure was on the same order of magnitude as PCL and PMMA. The mechanical strength and low thrombogenicity of xSIBS therefore suggest it as a viable polymeric substrate for fabrication of prosthetic heart valves, and other cardiovascular devices.
doi:10.1021/acsami.5b07254 pmid:26398588 pmcid:PMC4608843 fatcat:dcqtwofn65gslemdgn3tbfzj6a

Anomalous conditions in the south-eastern Bering Sea, 1997: nutrients, phytoplankton and zooplankton

Dean A. Stockwell, Terry E. Whitledge, Stephan I. Zeeman, Kenneth O. Coyle, Jeffrey M. Napp, Richard D. Brodeur, Alexei I. Pinchuk, George L. Hunt
2001 Fisheries Oceanography  
Anomalies in the regional weather over the southeastern Bering Sea during spring and summer of 1997 resulted in significant differences in nutrient availability, phytoplankton species composition, eScholarship provides open access, scholarly publishing services to the University of California and delivers a dynamic research platform to scholars worldwide. and zooplankton abundance over the continental shelf as compared with measurements in the 1980s. Calm winds and the reduction of cloud cover
more » ... ion of cloud cover in spring and summer produced a very shallow mixed layer in which nitrate and silicate were depleted after an April diatom bloom. High submarine light levels allowed subsequent phytoplankton growth below the pycnocline and eventual depletion of nitrate from the water column to depths of 70 m or more. Thus, total new production during 1997 may have exceeded that of previous years when nitrate was not depleted below the pycnocline.
doi:10.1046/j.1365-2419.2001.00158.x fatcat:f7jc64jso5gn3pygf54avvqwxi