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Sample records for reaktorov rnts kurchatovskij

  1. Self-assembled rosette nanotubes for incorporating hydrophobic drugs in physiological environments

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    Shang Song

    2011-01-01

    Full Text Available Shang Song1, Yupeng Chen1,2, Zhimin Yan4, Hicham Fenniri4, Thomas J Webster1,31School of Engineering, 2Department of Chemistry, 3Department of Orthopaedics, Brown University, Providence, RI, USA; 4National Institute for Nanotechnology and Department of Chemistry, National Research Council and University of Alberta, Edmonton, CanadaAbstract: Rosette nanotubes (RNTs are novel, biomimetic, injectable, self-assembled nanomaterials. In previous studies, materials coated with RNTs have significantly increased cell growth (eg, osteoblasts, chondrocytes, and endothelial cells due to the favorable cellular environment created by RNTs. It has also been suggested that the tubular RNT structures formed by base stacking and hydrophobic interactions can be used for drug delivery, and this possibility has not been studied to date. Here we investigated methods to load and deliver tamoxifen (TAM, a hydrophobic anticancer drug using two different types of RNTs: single-base RNTs and twin-base RNTs. Drug-loaded RNTs were characterized by nuclear magnetic resonance spectroscopy, diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY NMR, and ultraviolet-visible (UV-Vis spectroscopy at different ratios of twin-base RNTs to TAM. The results demonstrated successful incorporation of hydrophobic TAM into RNTs. Importantly, because of the hydrophilicity of the outer surface of the RNTs, TAM-loaded RNTs were dissolved in water, and thus have great potential to deliver hydrophobic drugs in various physiological environments. The results also showed that twin-base RNTs further improved TAM loading. Therefore, this study demonstrated that hydrophobic pharmaceutical agents (such as TAM, once considered hard to deliver, can be easily incorporated into RNTs for anticancer treatment purposes.Keywords: drug delivery, rosette nanotubes, self-assembly, tamoxifen

  2. Self-assembled rosette nanotubes encapsulate and slowly release dexamethasone

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    Chen Y

    2011-05-01

    Full Text Available Yupeng Chen1,2, Shang Song2, Zhimin Yan3, Hicham Fenniri3, Thomas J Webster2,41Department of Chemistry, Brown University, Providence, RI, USA; 2School of Engineering, Brown University, Providence, RI, USA; 3National Institute for Nanotechnology and Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada; 4Department of Orthopedics, Brown University, Providence, RI, USAAbstract: Rosette nanotubes (RNTs are novel, self-assembled, biomimetic, synthetic drug delivery materials suitable for numerous medical applications. Because of their amphiphilic character and hollow architecture, RNTs can be used to encapsulate and deliver hydrophobic drugs otherwise difficult to deliver in biological systems. Another advantage of using RNTs for drug delivery is their biocompatibility, low cytotoxicity, and their ability to engender a favorable, biologically-inspired environment for cell adhesion and growth. In this study, a method to incorporate dexamethasone (DEX, an inflammatory and a bone growth promoting steroid into RNTs was developed. The drug-loaded RNTs were characterized using diffusion ordered nuclear magnetic resonance spectroscopy (DOSY NMR and UV-Vis spectroscopy. Results showed for the first time that DEX can be easily and quickly encapsulated into RNTs and released to promote osteoblast (bone-forming cell functions over long periods of time. As a result, RNTs are presented as a novel material for the targeted delivery of hydrophobic drugs otherwise difficult to deliver.Keywords: nanotubes, drug delivery, self-assembly, physiological conditions

  3. Novel injectable biomimetic hydrogels with carbon nanofibers and self assembled rosette nanotubes for myocardial applications.

    Science.gov (United States)

    Meng, Xiangling; Stout, David A; Sun, Linlin; Beingessner, Rachel L; Fenniri, Hicham; Webster, Thomas J

    2013-04-01

    The objective of the present in vitro study was to investigate cardiomyocyte functions, specifically their adhesion and proliferation, on injectable scaffolds containing RNT (rosette nanotubes) and CNF (carbon nanofibers) in a pHEMA (poly(2-hydroxyethyl methacrylate)) hydrogel to determine their potential for myocardial tissue engineering applications. RNTs are novel biocompatible nanomaterials assembled from synthetic analogs of DNA bases guanine and cytosine that self-assemble within minutes when placed in aqueous solutions at body temperatures. These materials could potentially improve cardiomyocyte functions and solidification time of pHEMA and CNF composites. Because heart tissue is conductive, CNFs were added to pHEMA to increase the composite's conductivity. Our results showed that cardiomyocyte density increased after 4 h, 1 day, and 3 days with greater amounts of CNFs and greater amounts of RNTs in pHEMA (up to 10 mg mL(-1) CNFs and 0.05 mg mL(-1) RNTs). Factors that may have increased cardiomyocyte functions include greater wettability, conductivity, and an increase in surface nanoroughness with greater amounts of CNFs and RNTs. In effect, contact angles measured on the surface of the composites decreased while the conductivity and surface roughness increased as CNFs and RNTs content increased. Lastly, the ultimate tensile modulus decreased for composites with greater amounts of CNFs. In summary, the properties of these injectable composites make them promising candidates for myocardial tissue engineering applications and should be further studied.

  4. Self-assembled rosette nanotubes and poly(2-hydroxyethyl methacrylate) hydrogels promote skin cell functions.

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    Sun, Linlin; Li, Dongni; Hemraz, Usha D; Fenniri, Hicham; Webster, Thomas J

    2014-10-01

    The next generation skin of wound healing materials should stimulate skin regeneration by actively promoting appropriate cellular adhesion and proliferation. As materials with novel self-assembling and solidification properties when transitioning from room to body temperatures, rosette nanotubes (RNTs) may be such a proactive material. RNTs resemble naturally occurring nanostructures in the skin (such as collagen and keratin) assembling with noncovalent forces in physiological environments. Presenting desirable bioactive properties, RNTs have been used for various tissue engineering applications including increasing in vivo bone and cartilage regeneration. The objective of the current in vitro study was, for the first time, to improve properties of a commonly used hydrogel (poly(2-hydroxyethyl methacrylate) or pHEMA) for skin regeneration by incorporating one type of novel self-assembled RNTs, called TBL. Results showed for the first time increased keratinocyte and fibroblast proliferation on hydrogels coated with TBLs compared to those not coated with TBL. In this manner, this study provides the first evidence that TBL RNTs are promising for wound healing applications due to their optimal cytocompatibility, solidification, and mechanical properties and, thus, should be further studied for such applications.

  5. Studium radiačního poškození nádoby reaktoru VVER-440 jaderné elektrárny Dukovany

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    ŘÍHA, Tomáš

    2011-01-01

    Diplomová práce se zabývá radiačním poškozením reaktorových nádob jaderných reaktorů, konkrétně pak poškozením TNR 3. bloku jaderné elektrárny Dukovany. V obecné rovině práce popisuje mechanismy poškození reaktorových ocelí a formou rešerše uvádí možnosti sledování stavu materiálu a regenerace materiálových vlastností na jaderných elektrárnách po celém světě. Praktická část je zaměřena na interpretaci výsledků analýz provedených pomocí kódu MOBY-DICK. Jádrem těchto analýz je vývoj fluence neu...

  6. Radiation exposure to caregivers from patients undergoing common radionuclide therapies: a review.

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    Stefanoyiannis, A P; Ioannidou, S P; Round, W H; Carinou, E; Mavros, M N; Liotsou, T; Geronikola-Trapali, X; Armeniakos, I; Chatziioannou, S N

    2015-12-01

    The contribution of radionuclide therapies (RNTs) to effective patient treatment is widely appreciated. The administration of high doses has necessitated investigating the potential radiation hazard to caregivers from patients undergoing RNTs. This work aimed to review the literature regarding measured effective doses to caregivers from such patients. The main selection criterion was the presence of real radiation exposure measurements. The results were categorised according to the treatment protocol and dose parameters. Analysis of the collected data demonstrated that the measured effective dose values were within the dose constraints defined by the International Commission on Radiological Protection, provided that the radiation protection instructions were followed by both patients and caregivers. In conclusion, the radiation risk for caregivers was almost negligible. In this context, treatments could be administered more often on an outpatient basis, once cost-effectiveness criteria were established and radiation protection training and procedures were appropriately applied.

  7. Chiromers: conformation-driven mirror-image supramolecular chirality isomerism identified in a new class of helical rosette nanotubes

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    Hemraz, Usha D.; El-Bakkari, Mounir; Yamazaki, Takeshi; Cho, Jae-Young; Beingessner, Rachel L.; Fenniri, Hicham

    2014-07-01

    Rosette nanotubes are biologically inspired nanostructures, formed through the hierarchical organization of a hybrid DNA base analogue (G∧C), which features hydrogen-bonding arrays of guanine and cytosine. Several twin-G∧C motifs functionalized with chiral moieties, which undergo a self-assembly process under methanolic and aqueous conditions to produce helical rosette nanotubes (RNTs), were synthesized and characterized. The built-in molecular chirality in the twin-G∧C building blocks led to the supramolecular chirality exhibited by the RNTs, as evidenced by the CD activity. Depending on the motifs and environmental conditions, mirror-image supramolecular chirality due to absolute molecular chirality, solvent-induced and structure-dependent supramolecular chirality inversion, and pH-controlled chiroptical switching were observed.Rosette nanotubes are biologically inspired nanostructures, formed through the hierarchical organization of a hybrid DNA base analogue (G∧C), which features hydrogen-bonding arrays of guanine and cytosine. Several twin-G∧C motifs functionalized with chiral moieties, which undergo a self-assembly process under methanolic and aqueous conditions to produce helical rosette nanotubes (RNTs), were synthesized and characterized. The built-in molecular chirality in the twin-G∧C building blocks led to the supramolecular chirality exhibited by the RNTs, as evidenced by the CD activity. Depending on the motifs and environmental conditions, mirror-image supramolecular chirality due to absolute molecular chirality, solvent-induced and structure-dependent supramolecular chirality inversion, and pH-controlled chiroptical switching were observed. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00340c

  8. Review suggests direct pulp capping with MTA more effective than calcium hydroxide.

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    Rasaratnam, Lakshmi

    2016-09-01

    Data sourcesPubMed, the Cochrane Library, Embase, and the Web of Knowledge.Study selectionRandomised controlled trials (RCTs) or retrospective non-randomised trials (RNTs) of direct pulp capping in patients comparing mineral trioxide aggregate (MTA) with calcium hydroxide (CH) were considered.Data extraction and synthesisTwo reviewers independently abstracted data. Risk of bias for the RCTs was assessed using the Cochrane risk of bias tool and RNTs were assessed according to the methodological index for non-randomised studies. Different study designs were analysed separately.ResultsThirteen studies were included, ten of which were RCTs. Meta-analysis demonstrated a significantly higher success rate for MTA compared with the CH-capped groups. For RCT studies (2 studies, 405 teeth): OR = 2.26; (95% CI, 1.33-3.85; P = .003) and for RNTs (3 studies - 526 teeth): OR = 2.88; (95% CI, 1.86-4.44; P MTA showing significantly less inflammation compared with CH samples (OR = 4.56; 95% CI, 2.65 7.83; P MTA than CH-capped groups (OR = 3.56; 95% CI, 1.89 6.70; P MTA appears to be a suitable replacement of CH used for direct pulp capping.

  9. Metal hydride heat pump engineering demonstration and evaluation model

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    Lynch, Franklin E.

    1993-01-01

    Future generations of portable life support systems (PLSS's) for space suites (extravehicular mobility units or EMU's) may require regenerable nonventing thermal sinks (RNTS's). For purposes of mobility, a PLSS must be as light and compact as possible. Previous venting PLSS's have employed water sublimators to reject metabolic and equipment heat from EMU's. It is desirable for long-duration future space missions to minimize the use of water and other consumables that need to be periodically resupplied. The emission of water vapor also interferes with some types of instrumentation that might be used in future space exploration. The test article is a type of RNTS based on a metal hydride heat pump (MHHP). The task of reservicing EMU's after use must be made less demanding in terms of time, procedures, and equipment. The capability for quick turnaround post-EVA servicing (30 minutes) is a challenging requirement for many of the RNTS options. The MHHP is a very simple option that can be regenerated in the airlock within the 30 minute limit by the application of a heating source and a cooling sink. In addition, advanced PLSS's must provide a greater degree of automatic control, relieving astronauts of the need to manually adjust temperatures in their liquid cooled ventilation garments (LCVG's). The MHHP includes automatic coolant controls with the ability to follow thermal load swings from minimum to maximum in seconds. The MHHP includes a coolant loop subsystem with pump and controls, regeneration equipment for post-EVA servicing, and a PC-based data acquisition and control system (DACS).

  10. Conception et réalisation d'une instrumentation terminale intégrée en chirurgie mini-invasive robotisée

    OpenAIRE

    Van Meer, Frédérick

    2005-01-01

    On assiste depuis quelques années à l'émergence d'une robotique médicale proposée pour accroître la précision des actes, améliorer les conditions de travail de l'équipe chirurgicale et le confort du patient. Nos recherches s'inscrivent dans le projet national EndoXiroB du RNTS dont l'objectif est la réalisation d'un ensemble robotisé de chirurgie mini-invasive. Elles sont dédiées à la conception et à la réalisation, en s'appuyant sur les technologies microsystèmes, d' une instrumentation chir...

  11. Repetitive negative thinking and suicide: a burgeoning literature with need for further exploration.

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    Law, Keyne C; Tucker, Raymond P

    2017-08-24

    Extant research has found a significant overlap between various repetitive negative thinking (RNT) patterns, such as rumination and worry, across different affective disorders implicating that the process of repetitive negative thinking is likely trans-diagnostic. Furthermore, RNT patterns at the core of psychiatric disorders associated with suicide (e.g., rumination and worry) have been found to be associated with suicide even after accounting for the disorder. A synthesis of existing literature on repetitive negative thoughts suggest that following negative emotional experiences, RNTs may lead to a sense of entrapment and hopelessness that may contribute to the onset of suicidal ideation and then facilitate the transition from thinking about suicide to making a suicide attempt by increasing an individual's capability for suicide through repetitive exposure to violent thoughts and imagery associated with suicide. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Generation of Attosecond X-Ray Pulse through Coherent Relativistic Nonlinear Thomson Scattering

    CERN Document Server

    Lee, K; Jeong, Y U; Lee, B C; Park, S H

    2005-01-01

    In contrast to some recent experimental results, which state that the Nonlinear Thomson Scattered (NTS) radiation is incoherent, a coherent condition under which the scattered radiation of an incident laser pulse by a bunch of electrons can be coherently superposed has been investigated. The Coherent Relativistic Nonlinear Thomson Scattered (C-RNTS) radiation makes it possible utilizing the ultra-short pulse nature of NTS radiation with a bunch of electrons, such as plasma or electron beams. A numerical simulation shows that a 25 attosecond X-ray pulse can be generated by irradiating an ultra-intense laser pulse of 4x10(19) W/cm2 on an ultra-thin solid target of 50 nm thickness, which is commercially available. The coherent condition can be easily extended to an electron beam from accelerators. Different from the solid target, much narrower electron beam is required for the generation of an attosecond pulse. Instead, this condition could be applied for the generation of intense Compton scattered X-rays with a...

  13. CONFERENCES AND SYMPOSIA: Commemoration of the centenary of the birth of Academician L A Artsimovich(Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 18 February 2009; Joint session of the Research Council of the Russian Research Centre 'Kurchatov Institute', the Presidium of the Russian Academy of Sciences, and the Rosatom State Corporation, 18 March 2009)

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    Khalatnikov, Isaak M.; Fortov, Vladimir E.; Makarov, Aleksandr A.; Fridman, Aleksei M.; Martynenko, Yurii V.

    2009-12-01

    The scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS) devoted to the centenary of the birth of Academician L A Artsimovich was held on 18 February 2009 in the conference hall of the P N Lebedev Physical Institute, RAS. The following reports were presented at the session: (1) Khalatnikov I M (L D Landau Institute of Theoretical Physics, RAS, Chernogolovka, Moscow region) "Nonaccidental coincidences (Lev Andreevich Artsimovich)"; (2) Pashinin P P (A M Prokhorov Institute of General Physics, RAS, Moscow) "L A Artsimovich and inertial thermonuclear fusion"; (3) Fortov V E (Institute of Thermophysics of Extreme States of the Joint Institute for High Temperatures, RAS, Moscow) "High-power shock waves and extreme states of plasma"; (4) Fridman A M (Institute of Astronomy, RAS, Moscow) "Prediction and discovery of ultrastrong hydrodynamic instabilities caused by a velocity jump: theory and experiment"; (5) Smirnov V P (Russian Research Centre 'Kurchatov Institute', Moscow) "Retracing Artsimovich's path to the thermonuclear source of energy". On 18 March 2009, a joint session of the Learned Council of the Russian Research Centre 'Kurchatov Institute' (RNTsKI in Russ. abbr.), the Presidium of the Russian Academy of Sciences, and the Rosatom State Corporation took place at RNTsKI; the session was devoted to the 100th anniversary of the birth of Academician L A Artsimovich. The following talks were presented at the session: (1) Velikhov E P (Russian Research Centre 'Kurchatov Institute', Moscow) "Academician L A Artsimovich—the founder of our field of science and industry"; (2) Smirnov V P (Russian Research Centre 'Kurchatov Institute', Moscow) "Retracing Artsimovich's path to the thermonuclear source of energy"; (3) Boyarchuk A A (Division of General Physics and Astronomy, RAS, Moscow) "L A Artsimovich and astronomy"; (4) Martynenko Yu V (Institute of Nuclear Fusion, Russian Research Centre 'Kurchatov Institute', Moscow

  14. Regeneração natural de espécies arbóreas em fragmento de Floresta Estacional Semidecidual Montana, no domínio da Mata Atlântica, em Viçosa, MG

    Directory of Open Access Journals (Sweden)

    Cristina Cunha Garcia

    2011-12-01

    Full Text Available O presente estudo objetivou analisar a composição florística atual da regeneração natural, contrastando-a com levantamentos anteriores pertencentes a um monitoramento iniciado em 1992, em fragmento de Floresta Estacional Semidecidual Montana, em Viçosa, MG. Os locais de estudo correspondem a dez sítios escolhidos em função das características fisiográficas declividade, exposição e posição topográfica do terreno. Foram estimados os índices de regeneração natural por espécie para cada classe de tamanho de planta (RNC para obtenção do índice de regeneração natural total (RNT. Foram amostrados 3.516 indivíduos, pertencentes a 140 morfoespécies arbóreas, incluindo indivíduos de 10 cm a 3 m de altura e diâmetro a 1,3 m (DAP menor que 5 cm. O maior número de indivíduos foi amostrado nas famílias Rubiaceae, Fabaceae Mimosoideae, Monimiaceae, Fabaceae Papilionoideae, mas as famílias mais ricas foram Fabaceae Caesalpinoideae, Fabaceae Papilionoideae, Euphorbiaceae, Lauraceae, Myrtaceae e Rubiaceae. As espécies que apresentaram os maiores RNTs foram: Psychotria sessilis, Siparuna guianensis, Anadenanthera peregrina e Piptadenia gonoacantha. Este monitoramento sugere uma substituição contínua de espécies de estágios iniciais de sucessão por outras de estágios mais avançados, demonstrando a importância da proteção dos fragmentos florestais remanescentes para a manutenção ou aumento da biodiversidade da região.

  15. Effects of cigarette smoke exposure on nicotinic acetylcholine receptor subunits {alpha}7 and {beta}2 in the sudden infant death syndrome (SIDS) brainstem

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    Machaalani, Rita, E-mail: rita.machaalani@sydney.edu.au [Department of Medicine, The University of Sydney, NSW 2006 (Australia); Bosch Institute, The University of Sydney, NSW 2006 (Australia); The Children' s Hospital at Westmead, NSW 2145 (Australia); Say, Meichien [Department of Medicine, The University of Sydney, NSW 2006 (Australia); Bosch Institute, The University of Sydney, NSW 2006 (Australia); Waters, Karen A. [Department of Medicine, The University of Sydney, NSW 2006 (Australia); Bosch Institute, The University of Sydney, NSW 2006 (Australia); The Children' s Hospital at Westmead, NSW 2145 (Australia)

    2011-12-15

    It is postulated that nicotine, as the main neurotoxic constituent of cigarette smoke, influences SIDS risk through effects on nicotinic acetylcholine receptors (nAChRs) in brainstem nuclei that control respiration and arousal. This study compared {alpha}7 and {beta}2 nAChR subunit expression in eight nuclei of the caudal and rostral medulla and seven nuclei of the pons between SIDS (n = 46) and non-SIDS infants (n = 14). Evaluation for associations with known SIDS risk factors included comparison according to whether infants had a history of exposure to cigarette smoke in the home, and stratification for sleep position and gender. Compared to non-SIDS infants, SIDS infants had significantly decreased {alpha}7 in the caudal nucleus of the solitary tract (cNTS), gracile and cuneate nuclei, with decreased {beta}2 in the cNTS and increased {beta}2 in the facial. When considering only the SIDS cohort: 1-cigarette smoke exposure was associated with increased {alpha}7 in the vestibular nucleus and increased {beta}2 in the rostral dorsal motor nucleus of the vagus, rNTS and Cuneate, 2-there was a gender interaction for {alpha}7 in the gracile and cuneate, and {beta}2 in the cNTS and rostral arcuate nucleus, and 3-there was no effect of sleep position on {alpha}7, but prone sleep was associated with decreased {beta}2 in three nuclei of the pons. In conclusion, SIDS infants demonstrate differences in expression of {alpha}7 and {beta}2 nAChRs within brainstem nuclei that control respiration and arousal, which is independent on prior history of cigarette smoke exposure, especially for the NTS, with additional differences for smoke exposure ({beta}2), gender ({alpha}7 and {beta}2) and sleep position ({beta}2) evident. -- Highlights: Black-Right-Pointing-Pointer The 'normal' response to smoke exposure is decreased {alpha}7 and {beta}2 in certain nuclei. Black-Right-Pointing-Pointer SIDS infants have decreased {alpha}7 in cNTS, Grac and Cun. Black