Enhanced radiation resistant fiber optics

International Nuclear Information System (INIS)

Lyons, P.B.; Looney, L.D.

1993-01-01

A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures

Efficacy of six weeks infrared radiation therapy on chronic low back ...

African Journals Online (AJOL)

Background: Infrared radiation therapy is a modality widely used in Physiotherapy for the management of pain. The objective of this study was to determine the efficacy of six weeks infrared radiation therapy on pain intensity and functional disability index in subjects suffering from non- specific low back pain. Methods: The ...

Enhanced coherent undulator radiation from bunched electron beams

International Nuclear Information System (INIS)

Berryman, K.W.; Crosson, E.R.; Ricci, K.N.; Smith, T.I.

1996-01-01

When energetic bunches of electrons traverse an undulator field, they can spontaneously emit radiation both coherently and incoherently. Although it has generally been assumed that undulator radiation is incoherent at wavelengths short compared to the longitudinal size of the electron bunch, several recent observations have proved this assumption false. Furthermore, the appearance of coherent radiation is often accompanied by a significant increase in radiated power. Here we report observations of strongly enhanced coherent spontaneous radiation together with direct measurements, using transition radiation techniques, of the electron distributions responsible for the coherent emission. We also report demonstrated enhancements in the predicted spontaneous radiated power by as much as 6x10 4 using electron bunch compression. copyright 1996 American Institute of Physics

Better Efficacy of Synchrotron Spatially Microfractionated Radiation Therapy Than Uniform Radiation Therapy on Glioma

International Nuclear Information System (INIS)

Bouchet, Audrey; Bräuer-Krisch, Elke; Prezado, Yolanda; El Atifi, Michèle; Rogalev, Léonid; Le Clec'h, Céline; Laissue, Jean Albert; Pelletier, Laurent; Le Duc, Géraldine

2016-01-01

Purpose: Synchrotron microbeam radiation therapy (MRT) is based on the spatial fractionation of the incident, highly focused synchrotron beam into arrays of parallel microbeams, typically a few tens of microns wide and depositing several hundred grays. This irradiation modality was shown to have a high therapeutic impact on tumors, especially in intracranial locations. However, mechanisms responsible for such a property are not fully understood. Methods and Materials: Thanks to recent progress in dosimetry, we compared the effect of MRT and synchrotron broad beam (BB) radiation therapy delivered at comparable doses (equivalent to MRT valley dose) on tumor growth control and on classical radiobiological functions by histologic evaluation and/or transcriptomic analysis. Results: MRT significantly improved survival of rats bearing 9L intracranial glioma compared with BB radiation therapy delivered at a comparable dose (P<.001); the efficacy of MRT and BB radiation therapy was similar when the MRT dose was half that of BB. The greater efficacy of MRT was not correlated with a difference in cell proliferation (Mki67 and proliferating cell nuclear antigen) or in transcriptomic stimulation of angiogenesis (vascular endothelial growth factor A or tyrosine kinase with immunoglobulin-like and epidermal growth factor-like domains 2) but was correlated with a higher cell death rate (factor for apoptosis signals) and higher recruitment of macrophages (tyrosine kinase with immunoglobulin-like and epidermal growth factor-like domains 1 and CD68 transcripts) a few days after MRT. Conclusions: These results show the superiority of MRT over BB radiation therapy when applied at comparable doses, suggesting that spatial fractionation is responsible for a specific and particularly efficient tissue response. The higher induction of cell death and immune cell activation in brain tumors treated by MRT may be involved in such responses.

Better Efficacy of Synchrotron Spatially Microfractionated Radiation Therapy Than Uniform Radiation Therapy on Glioma

Energy Technology Data Exchange (ETDEWEB)

Bouchet, Audrey, E-mail: audrey.m.bouchet@gmail.com [Université Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble (France); Biomedical Beamline, European Synchrotron Radiation Facility, Grenoble (France); Bräuer-Krisch, Elke; Prezado, Yolanda [Biomedical Beamline, European Synchrotron Radiation Facility, Grenoble (France); El Atifi, Michèle [Université Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble (France); Grenoble University Hospital, Grenoble (France); Rogalev, Léonid; Le Clec' h, Céline [Biomedical Beamline, European Synchrotron Radiation Facility, Grenoble (France); Laissue, Jean Albert [University of Bern, Bern (Switzerland); Pelletier, Laurent, E-mail: laurent.pelletier@ujf-grenoble.fr [Université Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble (France); Grenoble University Hospital, Grenoble (France); Le Duc, Géraldine [Biomedical Beamline, European Synchrotron Radiation Facility, Grenoble (France)

2016-08-01

Purpose: Synchrotron microbeam radiation therapy (MRT) is based on the spatial fractionation of the incident, highly focused synchrotron beam into arrays of parallel microbeams, typically a few tens of microns wide and depositing several hundred grays. This irradiation modality was shown to have a high therapeutic impact on tumors, especially in intracranial locations. However, mechanisms responsible for such a property are not fully understood. Methods and Materials: Thanks to recent progress in dosimetry, we compared the effect of MRT and synchrotron broad beam (BB) radiation therapy delivered at comparable doses (equivalent to MRT valley dose) on tumor growth control and on classical radiobiological functions by histologic evaluation and/or transcriptomic analysis. Results: MRT significantly improved survival of rats bearing 9L intracranial glioma compared with BB radiation therapy delivered at a comparable dose (P<.001); the efficacy of MRT and BB radiation therapy was similar when the MRT dose was half that of BB. The greater efficacy of MRT was not correlated with a difference in cell proliferation (Mki67 and proliferating cell nuclear antigen) or in transcriptomic stimulation of angiogenesis (vascular endothelial growth factor A or tyrosine kinase with immunoglobulin-like and epidermal growth factor-like domains 2) but was correlated with a higher cell death rate (factor for apoptosis signals) and higher recruitment of macrophages (tyrosine kinase with immunoglobulin-like and epidermal growth factor-like domains 1 and CD68 transcripts) a few days after MRT. Conclusions: These results show the superiority of MRT over BB radiation therapy when applied at comparable doses, suggesting that spatial fractionation is responsible for a specific and particularly efficient tissue response. The higher induction of cell death and immune cell activation in brain tumors treated by MRT may be involved in such responses.

Leadership and Leader Developmental Self-Efficacy: Their Role in Enhancing Leader Development Efforts.

Science.gov (United States)

Murphy, Susan Elaine; Johnson, Stefanie K

2016-01-01

This chapter describes the role of two types of self-efficacy-leader self-efficacy and leader developmental efficacy-for enhancing leadership development. Practical implications for designing and developing leadership programs that take into account these two types of self-efficacy are discussed. © 2016 Wiley Periodicals, Inc., A Wiley Company.

Enhancement of Radiation Effects by Ursolic Acid in BGC-823 Human Adenocarcinoma Gastric Cancer Cell Line.

Directory of Open Access Journals (Sweden)

Yang Yang

Full Text Available Recent research has suggested that certain plant-derived polyphenols, i.e., ursolic acid (UA, which are reported to have antitumor activities, might be used to sensitize tumor cells to radiation therapy by inhibiting pathways leading to radiation therapy resistance. This experiment was designed to investigate the effects and possible mechanism of radiosensitization by UA in BGC-823 cell line from human adenocarcinoma gastric cancer in vitro. UA caused cytotoxicity in a dose-dependent manner, and we used a sub-cytotoxicity concentration of UA to test radioenhancement efficacy with UA in gastric cancer. Radiosensitivity was determined by clonogenic survival assay. Surviving fraction of the combined group with irradiation and sub-cytotoxicity UA significantly decreased compared with the irradiation group. The improved radiosensitization efficacy was associated with enhanced G2/M arrest, increased reactive oxygen species (ROS, down-regulated Ki-67 level and improved apoptosis. In conclusion, as UA demonstrated potent antiproliferation effect and synergistic effect, it could be used as a potential drug sensitizer for the application of radiotherapy.

Radiation Enhances Regulatory T Cell Representation

Energy Technology Data Exchange (ETDEWEB)

Kachikwu, Evelyn L.; Iwamoto, Keisuke S.; Liao, Yu-Pei; DeMarco, John J.; Agazaryan, Nzhde [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States); Economou, James S. [Department of Surgical Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States); McBride, William H. [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States); Schaue, Doerthe, E-mail: dschaue@mednet.ucla.edu [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States)

2011-11-15

Purpose: Immunotherapy could be a useful adjunct to standard cytotoxic therapies such as radiation in patients with micrometastatic disease, although successful integration of immunotherapy into treatment protocols will require further understanding of how standard therapies affect the generation of antitumor immune responses. This study was undertaken to evaluate the impact of radiation therapy (RT) on immunosuppressive T regulatory (Treg) cells. Methods and Materials: Treg cells were identified as a CD4{sup +}CD25{sup hi}Foxp3{sup +} lymphocyte subset, and their fate was followed in a murine TRAMP C1 model of prostate cancer in mice with and without RT. Results: CD4{sup +}CD25{sup hi}Foxp3{sup +} Treg cells increased in immune organs after local leg or whole-body radiation. A large part, but not all, of this increase after leg-only irradiation could be ascribed to radiation scatter and Treg cells being intrinsically more radiation resistant than other lymphocyte subpopulations, resulting in their selection. Their functional activity on a per-cell basis was not affected by radiation exposure. Similar findings were made with mice receiving local RT to murine prostate tumors growing in the leg. The importance of the Treg cell population in the response to RT was shown by systemic elimination of Treg cells, which greatly enhanced radiation-induced tumor regression. Conclusions: We conclude that Treg cells are more resistant to radiation than other lymphocytes, resulting in their preferential increase. Treg cells may form an important homeostatic mechanism for tissues injured by radiation, and in a tumor context, they may assist in immune evasion during therapy. Targeting this population may allow enhancement of radiotherapeutic benefit through immune modulation.

Radiation Enhances Regulatory T Cell Representation

International Nuclear Information System (INIS)

Kachikwu, Evelyn L.; Iwamoto, Keisuke S.; Liao, Yu-Pei; DeMarco, John J.; Agazaryan, Nzhde; Economou, James S.; McBride, William H.; Schaue, Dörthe

2011-01-01

Purpose: Immunotherapy could be a useful adjunct to standard cytotoxic therapies such as radiation in patients with micrometastatic disease, although successful integration of immunotherapy into treatment protocols will require further understanding of how standard therapies affect the generation of antitumor immune responses. This study was undertaken to evaluate the impact of radiation therapy (RT) on immunosuppressive T regulatory (Treg) cells. Methods and Materials: Treg cells were identified as a CD4 + CD25 hi Foxp3 + lymphocyte subset, and their fate was followed in a murine TRAMP C1 model of prostate cancer in mice with and without RT. Results: CD4 + CD25 hi Foxp3 + Treg cells increased in immune organs after local leg or whole-body radiation. A large part, but not all, of this increase after leg-only irradiation could be ascribed to radiation scatter and Treg cells being intrinsically more radiation resistant than other lymphocyte subpopulations, resulting in their selection. Their functional activity on a per-cell basis was not affected by radiation exposure. Similar findings were made with mice receiving local RT to murine prostate tumors growing in the leg. The importance of the Treg cell population in the response to RT was shown by systemic elimination of Treg cells, which greatly enhanced radiation-induced tumor regression. Conclusions: We conclude that Treg cells are more resistant to radiation than other lymphocytes, resulting in their preferential increase. Treg cells may form an important homeostatic mechanism for tissues injured by radiation, and in a tumor context, they may assist in immune evasion during therapy. Targeting this population may allow enhancement of radiotherapeutic benefit through immune modulation.

Biofilm disruption with rotating microrods enhances antimicrobial efficacy

Energy Technology Data Exchange (ETDEWEB)

Mair, Lamar O., E-mail: Lamar.Mair@gmail.com [Weinberg Medical Physics, Inc., North Bethesda, MD (United States); Nacev, Aleksandar; Hilaman, Ryan; Stepanov, Pavel Y.; Chowdhury, Sagar; Jafari, Sahar [Weinberg Medical Physics, Inc., North Bethesda, MD (United States); Hausfeld, Jeffrey [School of Medicine and Health Sciences, George Washington University, WA (United States); Karlsson, Amy J. [Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD (United States); Shirtliff, Mark E. [School of Dentistry, University of Maryland, Baltimore, MD (United States); Shapiro, Benjamin [Fischell Department of Bioengineering, University of Maryland, College Park, MD (United States); Weinberg, Irving N. [Weinberg Medical Physics, Inc., North Bethesda, MD (United States)

2017-04-01

Biofilms are a common and persistent cause of numerous illnesses. Compared to planktonic microbes, biofilm residing cells often demonstrate significant resistance to antimicrobial agents. Thus, methods for dislodging cells from the biofilm may increase the antimicrobial susceptibility of such cells, and serve as a mechanical means of increasing antimicrobial efficacy. Using Aspergillus fumigatus as a model microbe, we magnetically rotate microrods in and around biofilm. We show that such rods can improve the efficacy of antimicrobial Amphotericin B treatments in vitro. This work represents a first step in using kinetic magnetic particle therapy for disrupting fungal biofilms. - Highlights: • Fungal biofilms have been implicated in a variety of medical ailments. • Magnetic microrods, grown via electroplating, were rotated in and around fungal biofilms. • Rotating microrods potentiate the effectiveness of antimicrobial drug. • Antimicrobial efficacy may be enhanced due to increased mixing.

Biofilm disruption with rotating microrods enhances antimicrobial efficacy

International Nuclear Information System (INIS)

Mair, Lamar O.; Nacev, Aleksandar; Hilaman, Ryan; Stepanov, Pavel Y.; Chowdhury, Sagar; Jafari, Sahar; Hausfeld, Jeffrey; Karlsson, Amy J.; Shirtliff, Mark E.; Shapiro, Benjamin; Weinberg, Irving N.

2017-01-01

Biofilms are a common and persistent cause of numerous illnesses. Compared to planktonic microbes, biofilm residing cells often demonstrate significant resistance to antimicrobial agents. Thus, methods for dislodging cells from the biofilm may increase the antimicrobial susceptibility of such cells, and serve as a mechanical means of increasing antimicrobial efficacy. Using Aspergillus fumigatus as a model microbe, we magnetically rotate microrods in and around biofilm. We show that such rods can improve the efficacy of antimicrobial Amphotericin B treatments in vitro. This work represents a first step in using kinetic magnetic particle therapy for disrupting fungal biofilms. - Highlights: • Fungal biofilms have been implicated in a variety of medical ailments. • Magnetic microrods, grown via electroplating, were rotated in and around fungal biofilms. • Rotating microrods potentiate the effectiveness of antimicrobial drug. • Antimicrobial efficacy may be enhanced due to increased mixing.

Low-dose radiation potentiates the therapeutic efficacy of folate receptor-targeted hapten therapy.

Science.gov (United States)

Sega, Emanuela I; Lu, Yingjuan; Ringor, Michael; Leamon, Christopher P; Low, Philip S

2008-06-01

Human cancers frequently overexpress a high-affinity cell-surface receptor for the vitamin folic acid. Highly immunogenic haptens can be targeted to folate receptor-expressing cell surfaces by administration of folate-hapten conjugates, rendering the decorated tumor cell surfaces more recognizable by the immune system. Treatment of antihapten-immunized mice with folate-hapten constructs results in elimination of moderately sized tumors by the immune system. However, when subcutaneous tumors exceed 300 mm(3) before initiation of therapy, antitumor activity is significantly decreased. In an effort to enhance the efficacy of folate-targeted hapten immunotherapy (FTHI) against large tumors, we explored the combination of targeted hapten immunotherapy with low-dose radiotherapy. Mice bearing 300-mm(3) subcutaneous tumors were treated concurrently with FTHI (500 nmol/kg of folate conjugated to fluorescein isothiocyanate, 20,000 U/dose of interleukin 2, and 25,000 U/dose of interferon alpha) and low-dose radiotherapy (3 Gy/dose focused directly on the desired tumor mass). The efficacy of therapy was evaluated by measuring tumor volume. Tumor growth analyses show that radiotherapy synergizes with FTHI in antihapten-immunized mice, thereby allowing for cures of animals bearing tumors greater than 300 mm(3). More importantly, nonirradiated distal tumor masses in animals containing locally irradiated tumors also showed improved response to hapten immunotherapy, suggesting that not all tumor lesions must be identified and irradiated to benefit from the combination therapy. These results suggest that simultaneous treatment with FTHI and radiation therapy can enhance systemic antitumor activity in tumor-bearing mice.

Low-Dose Radiation Potentiates the Therapeutic Efficacy of Folate Receptor-Targeted Hapten Therapy

International Nuclear Information System (INIS)

Sega, Emanuela I.; Lu Yingjuan; Ringor, Michael; Leamon, Christopher P.; Low, Philip S.

2008-01-01

Purpose: Human cancers frequently overexpress a high-affinity cell-surface receptor for the vitamin folic acid. Highly immunogenic haptens can be targeted to folate receptor-expressing cell surfaces by administration of folate-hapten conjugates, rendering the decorated tumor cell surfaces more recognizable by the immune system. Treatment of antihapten-immunized mice with folate-hapten constructs results in elimination of moderately sized tumors by the immune system. However, when subcutaneous tumors exceed 300 mm 3 before initiation of therapy, antitumor activity is significantly decreased. In an effort to enhance the efficacy of folate-targeted hapten immunotherapy (FTHI) against large tumors, we explored the combination of targeted hapten immunotherapy with low-dose radiotherapy. Methods and Materials: Mice bearing 300-mm 3 subcutaneous tumors were treated concurrently with FTHI (500 nmol/kg of folate conjugated to fluorescein isothiocyanate, 20,000 U/dose of interleukin 2, and 25,000 U/dose of interferon α) and low-dose radiotherapy (3 Gy/dose focused directly on the desired tumor mass). The efficacy of therapy was evaluated by measuring tumor volume. Results: Tumor growth analyses show that radiotherapy synergizes with FTHI in antihapten-immunized mice, thereby allowing for cures of animals bearing tumors greater than 300 mm 3 . More importantly, nonirradiated distal tumor masses in animals containing locally irradiated tumors also showed improved response to hapten immunotherapy, suggesting that not all tumor lesions must be identified and irradiated to benefit from the combination therapy. Conclusions: These results suggest that simultaneous treatment with FTHI and radiation therapy can enhance systemic antitumor activity in tumor-bearing mice

Effects of glucocorticoid hormones on radiation induced and 12-O-tetradecanoylphorbol-13-acetate enhanced radiation transformation in vitro

International Nuclear Information System (INIS)

Kennedy, A.R.; Umans, R.S.

1988-01-01

We have studied the interactions of glucocorticoid hormones with radiation in the induction of transformation in vitro in C3AH10T1/2 cells. We have observed that cortisone has its primary enhancing effect on radiation transformation when present after the radiation exposure during the ''expression period'', or the time after carcinogen exposure during which promoting agents have been shown to enhance radiation transformation in vitro, and that two different glucocorticoid hormones, dexamethasone and cortisone, have a suppressive effect on the 12-O-tetradecanoylphorbol-13-acetate (TPA) enhancement of radiation transformation in vitro

Line-Enhanced Deformable Registration of Pulmonary Computed Tomography Images Before and After Radiation Therapy With Radiation-Induced Fibrosis

Science.gov (United States)

Sensakovic, William F.; Maxim, Peter; Diehn, Maximilian; Loo, Billy W.; Xing, Lei

2018-01-01

Purpose: The deformable registration of pulmonary computed tomography images before and after radiation therapy is challenging due to anatomic changes from radiation fibrosis. We hypothesize that a line-enhanced registration algorithm can reduce landmark error over the entire lung, including the irradiated regions, when compared to an intensity-based deformable registration algorithm. Materials: Two intensity-based B-spline deformable registration algorithms of pre-radiation therapy and post-radiation therapy images were compared. The first was a control intensity–based algorithm that utilized computed tomography images without modification. The second was a line enhancement algorithm that incorporated a Hessian-based line enhancement filter prior to deformable image registration. Registrations were evaluated based on the landmark error between user-identified landmark pairs and the overlap ratio. Results: Twenty-one patients with pre-radiation therapy and post-radiation therapy scans were included. The median time interval between scans was 1.2 years (range: 0.3-3.3 years). Median landmark errors for the line enhancement algorithm were significantly lower than those for the control algorithm over the entire lung (1.67 vs 1.83 mm; P 5 Gy (2.25 vs 3.31; P 5 Gy dose interval demonstrated a significant inverse relationship with post-radiation therapy fibrosis enhancement after line enhancement filtration (Pearson correlation coefficient = −0.48; P = .03). Conclusion: The line enhancement registration algorithm is a promising method for registering images before and after radiation therapy. PMID:29343206

Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography.

Science.gov (United States)

Jost, Gregor; Mensing, Tristan; Golfier, Sven; Lawaczeck, Rüdiger; Pietsch, Hubertus; Hütter, Joachim; Cibik, Levent; Gerlach, Martin; Krumrey, Michael; Fratzscher, Daniel; Arkadiev, Vladimir; Wedell, Reiner; Haschke, Michael; Langhoff, Norbert; Wust, Peter; Lüdemann, Lutz

2009-06-01

Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional x-ray optical module which converts the polychromatic, fan-shaped CT beam into a monochromatized and focused beam for energy-tuned photoelectric-enhanced radiotherapy. A dedicated x-ray optical module designed for spatial collimation, focusing, and monochromatization was mounted at the exit of the x-ray tube of a clinical CT unit. Spectrally resolved measurements of the resulting beam were performed using an energy-dispersive detection system calibrated by synchrotron radiation. The spatial photon fluence was determined by film dosimetry. Depth-dose measurements were performed and compared to the polychromatic CT and a therapeutic 6 MV beam. The spatial dose distribution in phantoms using a rotating radiation source (quasimonochromatic CT and 6 MV, respectively) was investigated by gel dosimetry. The photoelectric dose enhancement for an iodine fraction of 1% in tissue was calculated and verified experimentally. The x-ray optical module selectively filters the energy of the tungsten Kalpha emission line with an FWHM of 5 keV. The relative photon fluence distribution demonstrates the focusing characteristic of the x-ray optical module. A beam width of about 3 mm was determined at the isocenter of the CT gantry. The depth-dose measurements resulted in a half-depth value of approximately 36 mm for the CT beams (quasi-monochromatic, polychromatic) compared to 154 mm for the 6 MV beam. The rotation of the radiation source leads to a steep dose gradient at the center of rotation; the gel dosimetry yields an entrance-to-peak dose ratio of 1:10.8 for the quasi-monochromatic CT and 1:37.3 for a 6 MV beam of the same size. The photoelectric dose enhancement

Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography

International Nuclear Information System (INIS)

Jost, Gregor; Mensing, Tristan; Golfier, Sven; Lawaczeck, Ruediger; Pietsch, Hubertus; Huetter, Joachim; Cibik, Levent; Gerlach, Martin; Krumrey, Michael; Fratzscher, Daniel; Arkadiev, Vladimir; Wedell, Reiner; Haschke, Michael; Langhoff, Norbert; Wust, Peter; Luedemann, Lutz

2009-01-01

Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional x-ray optical module which converts the polychromatic, fan-shaped CT beam into a monochromatized and focused beam for energy-tuned photoelectric-enhanced radiotherapy. A dedicated x-ray optical module designed for spatial collimation, focusing, and monochromatization was mounted at the exit of the x-ray tube of a clinical CT unit. Spectrally resolved measurements of the resulting beam were performed using an energy-dispersive detection system calibrated by synchrotron radiation. The spatial photon fluence was determined by film dosimetry. Depth-dose measurements were performed and compared to the polychromatic CT and a therapeutic 6 MV beam. The spatial dose distribution in phantoms using a rotating radiation source (quasi-monochromatic CT and 6 MV, respectively) was investigated by gel dosimetry. The photoelectric dose enhancement for an iodine fraction of 1% in tissue was calculated and verified experimentally. The x-ray optical module selectively filters the energy of the tungsten Kα emission line with an FWHM of 5 keV. The relative photon fluence distribution demonstrates the focusing characteristic of the x-ray optical module. A beam width of about 3 mm was determined at the isocenter of the CT gantry. The depth-dose measurements resulted in a half-depth value of approximately 36 mm for the CT beams (quasi-monochromatic, polychromatic) compared to 154 mm for the 6 MV beam. The rotation of the radiation source leads to a steep dose gradient at the center of rotation; the gel dosimetry yields an entrance-to-peak dose ratio of 1:10.8 for the quasi-monochromatic CT and 1:37.3 for a 6 MV beam of the same size. The photoelectric dose enhancement factor

Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography

Energy Technology Data Exchange (ETDEWEB)

Jost, Gregor; Mensing, Tristan; Golfier, Sven; Lawaczeck, Ruediger; Pietsch, Hubertus; Huetter, Joachim; Cibik, Levent; Gerlach, Martin; Krumrey, Michael; Fratzscher, Daniel; Arkadiev, Vladimir; Wedell, Reiner; Haschke, Michael; Langhoff, Norbert; Wust, Peter; Luedemann, Lutz [TRG Diagnostic Imaging, Bayer Schering Pharma AG, 13353 Berlin (Germany); Department of Radiotherapy, Charite Medical Centre, 13353 Berlin (Germany); TRG Diagnostic Imaging, Bayer Schering Pharma AG, 13353 Berlin (Germany); Physikalisch-Technische Bundesanstalt, 10587 Berlin (Germany); Institute of Applied Photonics e.V., 12489 Berlin (Germany); Institute for Scientific Instruments GmbH, 12489 Berlin (Germany); Department of Radiotherapy, Charite Medical Centre, 13353 Berlin (Germany)

2009-06-15

Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional x-ray optical module which converts the polychromatic, fan-shaped CT beam into a monochromatized and focused beam for energy-tuned photoelectric-enhanced radiotherapy. A dedicated x-ray optical module designed for spatial collimation, focusing, and monochromatization was mounted at the exit of the x-ray tube of a clinical CT unit. Spectrally resolved measurements of the resulting beam were performed using an energy-dispersive detection system calibrated by synchrotron radiation. The spatial photon fluence was determined by film dosimetry. Depth-dose measurements were performed and compared to the polychromatic CT and a therapeutic 6 MV beam. The spatial dose distribution in phantoms using a rotating radiation source (quasi-monochromatic CT and 6 MV, respectively) was investigated by gel dosimetry. The photoelectric dose enhancement for an iodine fraction of 1% in tissue was calculated and verified experimentally. The x-ray optical module selectively filters the energy of the tungsten K{alpha} emission line with an FWHM of 5 keV. The relative photon fluence distribution demonstrates the focusing characteristic of the x-ray optical module. A beam width of about 3 mm was determined at the isocenter of the CT gantry. The depth-dose measurements resulted in a half-depth value of approximately 36 mm for the CT beams (quasi-monochromatic, polychromatic) compared to 154 mm for the 6 MV beam. The rotation of the radiation source leads to a steep dose gradient at the center of rotation; the gel dosimetry yields an entrance-to-peak dose ratio of 1:10.8 for the quasi-monochromatic CT and 1:37.3 for a 6 MV beam of the same size. The photoelectric dose enhancement

The enhancement of students' mathematical self-efficacy through teaching with metacognitive scaffolding approach

Science.gov (United States)

Prabawanto, S.

2018-05-01

This research aims to investigate the enhancement of students’ mathematical self- efficacy through teaching with metacognitive scaffolding approach. This research used a quasi- experimental design with pre-post respon control. The subjects were pre-service elementary school teachers in a state university in Bandung. In this study, there were two groups: experimental and control groups. The experimental group consists of 60 students who acquire teaching mathematics under metacognitive approach, while the control group consists of 58 students who acquire teaching mathematics under direct approach. Students were classified into three categories based on the mathematical prior ability, namely high, middle, and low. Data collection instruments consist of mathematical self-efficacy instruments. By using mean difference test, two conclusions of the research: (1) there is a significant difference in the enhancement of mathematical self-efficacy between the students who attended the course under metacognitive scaffolding approach and students who attended the course under direct approach, and (2) there is no significant interaction effect of teaching approaches and ability level based on the mathematical prior ability toward enhancement of students’ mathematical self-efficacy.

Intraspecific responses of 188 rice cultivars to enhanced UVB radiation

International Nuclear Information System (INIS)

Dai, Q.; Peng, A.; Chavez, A.Q.; Vergara, B.S.

1994-01-01

Phytotron studies were conducted to determine the intraspecific variation in sensitivity of rice (Oryza sativa L.) to enhanced UVB and to test the hypothesis that rice cultivars originating from regions with higher ambient UVB radiation are more tolerant to enhanced UVB. Out of the 188 rice cultivars (from various rice growing regions and ecosystems) tested, 143 had significantly reduced plant height, 52 had smaller leaf area, 61 had lower plant dry weight and 41 had less tiller number under elevated UVB radiation (13.0 kJ m −2 day −1 ) for 3 weeks. Six cultivars showed significant positive growth response to enhanced UVB radiation, although the mechanism is not clear at present. These six cultivars were from the summer rice crop of Bangladesh and from high elevation rice areas where prevailing UVB radiation is most likely to be greater. However, there was no correlation between the dry matter changes under enhanced UVB and the ambient UVB level at the origin of the cultivar across the 188 cultivars tested. Therefore, cultivars originating from regions with higher ambient UVB are not necessarily more tolerant to enhanced UVB radiation. (author)

Enhancing of Self-Efficacy in Teacher Education Students

Science.gov (United States)

Malinauskas, Romualdas K.

2017-01-01

In this study, the effectiveness of training module on enhancing self-efficacy in teacher education students was investigated. Sixty-eight (68) teacher education students (M age = 22.74; SD = 0.57) participated in this study, 36 of whom were assigned to an experimental group and the other 32 were assigned to a control group. The training module on…

Investigation of the protection possibilities against enhanced radiation warhead

International Nuclear Information System (INIS)

Sahin, S.; Erisen, A.; Selvi, S.; Yalcin, S.

1980-01-01

To evaluate an enhanced radiation protection for the tank crew against the neutron bomb, we first have analysed the propagation of the 14.1 MeV neutron in air in S 8 approximation. Three new tank wall proposals for enhanced radiation protection have been discussed in S 4 approximation. The best protection for the tank crew against the neutron bomb radiation has been achieved by covering the internal tank wall with a borated polyethylene layer. However the radiation damage through the neutron bomb cannot be degradated to the radiation damage level by a standard nuclear warhead of comparable energy release. In the course of this study a 27 group hard spectra data library has been used. (orig.) 891 HP/orig. 892 CKA [de

Dose enhancement by synchrotron radiation and heavy atoms for the treatment of gliomas

International Nuclear Information System (INIS)

Bobyk, L.

2010-11-01

High grade gliomas are brain tumors of bad prognosis. The standard therapeutic treatment combines surgery, radiotherapy and sometimes use of temozolomide (chemotherapy agent). Healthy tissues radio-sensitivity is a major limitation for radiotherapy treatment. The stereotactic radiotherapy by synchrotron radiation is an innovative technique which combines a low energy radiation (lower 100 keV) with the presence of heavy atoms in the tumoral zone. Such an approach is used to increase the differential of dose deposited in the tumor compared to surrounding healthy tissues. In this study, several compounds containing heavy atoms such as chemotherapy agents: cisplatin/carbo-platin, a DNA base analog: 5-iodo-2'-deoxyuridine (IUdR) and gold nano-particles were considered. The dose enhancement factor induced by the presence of these compounds located for some of them in the extracellular medium or inside the cells for others, was determined using in vitro studies. Thereafter, in vivo studies on rats bearing gliomas, were performed to study the toxicity, the kinetic of distribution and the localization of these compounds together with their potential efficacy of treatment combining intracerebral injection with low energy radiation. (author)

Caffeine Markedly Enhanced Radiation-Induced Bystander Effects

International Nuclear Information System (INIS)

Jiang Erkang; Wu Lijun

2009-01-01

In this paper it is shown that incubation with 2 mM caffeine enhanced significantly the MN (micronucleus) formation in both the 1 cGy α-particle irradiated and non-irradiated bystander regions. Moreover, caffeine treatment made the non-irradiated bystander cells more sensitive to damage signals. Treated by c-PTIO(2-(4-carboxy-phenyl)- 4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide), a nitric oxide (NO) scavenger, the MN frequencies were effectively inhibited, showing that nitric oxide might be very important in mediating the enhanced damage. These results indicated that caffeine enhanced the low dose α-particle radiation-induced damage in irradiated and non-irradiated bystander regions, and therefore it is important to investigate the relationship between the radiosensitizer and radiation-induced bystander effects (RIBE). (ion beam bioengineering)

Enhancing radiative energy transfer through thermal extraction

Science.gov (United States)

Tan, Yixuan; Liu, Baoan; Shen, Sheng; Yu, Zongfu

2016-06-01

Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a). In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics. Thermal extraction works by using a specially designed thermal extractor to convert and guide the near-field energy to the far field, as shown in Fig. 1b. The same blackbody as shown in Fig. 1a is placed closely below the thermal extractor with a spacing smaller than the thermal wavelength. The near-field coupling transfers radiative energy with a density greater than σT4. The thermal extractor, made from transparent and high-index or structured materials, does not emit or absorb any radiation. It transforms the near-field energy and sends it toward the far field. As a result, the total amount of far-field radiative heat dissipated by the same blackbody is greatly enhanced above SσT4, where S is the area of the emitter. This paper will review the progress in thermal

Good News in Bad News: How Negativity Enhances Economic Efficacy

OpenAIRE

Svensson, H.M.; Albæk, E.; van Dalen, A.; de Vreese, C.

2017-01-01

Negativity is a news ideology, and its negative effects on attitude formation are widely documented. Contrary to this view, the present study demonstrates that negative economic news can in fact be good news. Based on a two-wave national panel survey and a media content analysis, we show that individual exposure to negative economic news enhances internal economic efficacy, a sense of competence in and understanding of the economy. This is good news as internal economic efficacy may facilitat...

Relationship between knowledge, attitude, behavior, and self-efficacy on the radiation safety on dental hygienist

International Nuclear Information System (INIS)

Han, Eun Ok; Jun, Sung Hee

2008-01-01

The objective of this study is to draw an educational plant for reducing the probability of troubles caused by radiation for dental hygienists who are the major applicants of radiation equipments used in dental offices. This study investigated the knowledge and self-efficacy, which is the major variable that affects the attitude and behavior, on the radiation safety that is an educational approach. Also, this study obtained following results from a survey for 25 days from June 15, 2008 that was applied for 225 dental hygienists worked at dental offices and clinics in the area of Youngnam in order to verify the relationship between such variables. The average scores for the knowledge, attitude, and behavior were 54.28±16.33, 87.93±9.75, and 59.85±14.76, respectively. Also, the average score of the self-efficacy was 72.88±8.60. In the knowledge level for the radiation safety, ‘a case that prepares personal dosimeters’, ‘a case that establishes protection facilities’, ‘a case that presents 6⁓10 dental hygienists’, ‘a case that presents radiological technologists’, and ‘a case that is a general hospital’ represented high values. In the attitude level for the radiation safety, ‘a case who is a married person’, ‘a case that prepares personal dosimeters’, and ‘a case that is a general hospital’ showed high values. In the behavior level for the radiation safety, ‘a case that shows a career in dental hygienist or radiographic for 6⁓10 years’, ‘a case that attends radiation safety education’, ‘a case that establishes protection facilities’ showed high values. Also, in the self-efficacy level, ‘a case that who has a high education level more than graduate school education’ and ‘a case that establishes protection facilities’ represented high values. In the relationship between the knowledge, attitude, behavior, and self-efficacy for the radiation safety, it showed statistically significant differences in this

Relationship between knowledge, attitude, behavior, and self-efficacy on the radiation safety on dental hygienist

Energy Technology Data Exchange (ETDEWEB)

Han, Eun Ok; Jun, Sung Hee [Daegu Health College, Daegu (Korea, Republic of)

2008-11-15

The objective of this study is to draw an educational plant for reducing the probability of troubles caused by radiation for dental hygienists who are the major applicants of radiation equipments used in dental offices. This study investigated the knowledge and self-efficacy, which is the major variable that affects the attitude and behavior, on the radiation safety that is an educational approach. Also, this study obtained following results from a survey for 25 days from June 15, 2008 that was applied for 225 dental hygienists worked at dental offices and clinics in the area of Youngnam in order to verify the relationship between such variables. The average scores for the knowledge, attitude, and behavior were 54.28±16.33, 87.93±9.75, and 59.85±14.76, respectively. Also, the average score of the self-efficacy was 72.88±8.60. In the knowledge level for the radiation safety, ‘a case that prepares personal dosimeters’, ‘a case that establishes protection facilities’, ‘a case that presents 6⁓10 dental hygienists’, ‘a case that presents radiological technologists’, and ‘a case that is a general hospital’ represented high values. In the attitude level for the radiation safety, ‘a case who is a married person’, ‘a case that prepares personal dosimeters’, and ‘a case that is a general hospital’ showed high values. In the behavior level for the radiation safety, ‘a case that shows a career in dental hygienist or radiographic for 6⁓10 years’, ‘a case that attends radiation safety education’, ‘a case that establishes protection facilities’ showed high values. Also, in the self-efficacy level, ‘a case that who has a high education level more than graduate school education’ and ‘a case that establishes protection facilities’ represented high values. In the relationship between the knowledge, attitude, behavior, and self-efficacy for the radiation safety, it showed statistically significant differences in this

Enhanced radiation response in radioresistant MCF-7 cells by targeting peroxiredoxin II

Directory of Open Access Journals (Sweden)

Diaz AJG

2013-10-01

Full Text Available Anthony Joseph Gomez Diaz,1 Daniel Tamae,2 Yun Yen,3 JianJian Li,4 Tieli Wang1 1Department of Chemistry and Biochemistry, California State University at Dominguez Hills, Carson, CA, 2Center of Excellence in Environmental Toxicology, Department of Pharmacology, University of Pennsylvania, Philadelphia, PA, 3Department of Clinical and Molecular Pharmacology, Beckman Research Institute of City of Hope National Medical Center, Duarte, CA, 4Department of Radiation Oncology, University of California Davis, Sacramento, CA, USA Abstract: In our previous study, we identified that a protein target, peroxiredoxin II (PrxII, is overexpressed in radioresistant MCF+FIR3 breast-cancer cells and found that its expression and function is associated with breast-cancer radiation sensitivity or resistance. Small interference RNA (siRNA targeting PrxII gene expression was able to sensitize MCF+FIR3 radioresistant breast-cancer cells to ionizing radiation. The major focus of this work was to investigate how the radiation response of MCF+FIR3 radioresistant cells was affected by the siRNA that inhibits PrxII gene expression. Our results, presented here, show that silencing PrxII gene expression increased cellular toxicity by altering cellular thiol status, inhibiting Ca2+ efflux from the cells, and perturbing the intracellular Ca2+ homeostasis. By combining radiotherapy and siRNA technology, we hope to develop new therapeutic strategies that may have potential to enhance the efficacy of chemotherapeutic agents due to this technology's property of targeting to specific cancer-related genes. Keywords: siRNA, PrxII, radiation resistance, Ca2+, MCF+FIR3

Radiation effects on and dose enhancement of electronic materials

International Nuclear Information System (INIS)

Srour, J.R.; Long, D.M.

1984-01-01

This book describes radiation effects on and dose enhancement factors for electronic materials. Alteration of the electrical properties of solid-state devices and integrated circuits by impinging radiation is well-known. Such changes may cause an electronic subsystem to fail, thus there is currently great interest in devising methods for avoiding radiation-induced degradation. The development of radiation-hardened devices and circuits is an exciting approach to solving this problem for many applications, since it could minimize the need for shielding or other system hardening techniques. Part 1 describes the basic mechanisms of radiation effects on electronic materials, devices, and integrated circuits. Radiation effects in bulk silicon and in silicon devices are treated. Ionizing radiation effects in silicon dioxide films and silicon MOS devices are discussed. Single event phenomena are considered. Key literature references and a bibliography are provided. Part II provides tabulations of dose enhancement factors for electronic devices in x-ray and gamma-ray environments. The data are applicable to a wide range of semiconductor devices and selected types of capacitors. Radiation environments discussed find application in system design and in radiation test facilities

Structural Change of Biomolecules and Application of Synergistic Interaction by Radiation

International Nuclear Information System (INIS)

Kim, Jin Kyu; Kim, J. H.; Yang, J. S.

2008-12-01

It is expected that motivation and basic technologies for the future R and D plans can be provided from the results of this study. This study has been done to develop fundamentals for radiation applications based on the existing radiation technology, and to establish technical basis for enhancing efficacy of radiation utilization by studying the simultaneous application of ionizing radiation with another factor. Application of radiation technology together with the existing technologies to enhance the physical, chemical, biological characteristics through structural changes of biomolecules will exert a favorable influence on the creation of de novo scientific and industrial values. A theoretical model for the combined action of ionizing radiation with another factor can make it possible to predict a prior the maximum value of synergistic interaction and the conditions for it. Furthermore, the results of this study give a clues for establishment of fundamental theories associated with positive efficacy of radiation applications

Structural Change of Biomolecules and Application of Synergistic Interaction by Radiation

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Kyu; Kim, J. H.; Yang, J. S.

2008-12-15

It is expected that motivation and basic technologies for the future R and D plans can be provided from the results of this study. This study has been done to develop fundamentals for radiation applications based on the existing radiation technology, and to establish technical basis for enhancing efficacy of radiation utilization by studying the simultaneous application of ionizing radiation with another factor. Application of radiation technology together with the existing technologies to enhance the physical, chemical, biological characteristics through structural changes of biomolecules will exert a favorable influence on the creation of de novo scientific and industrial values. A theoretical model for the combined action of ionizing radiation with another factor can make it possible to predict a prior the maximum value of synergistic interaction and the conditions for it. Furthermore, the results of this study give a clues for establishment of fundamental theories associated with positive efficacy of radiation applications

Modification of biomolecules and combined actions by radiation

International Nuclear Information System (INIS)

Kim, Jin Kyu; Lee, J. W.; Kim, J. H.; Choi, J. I.; Song, B. S.; Kim, J. K.; Park, J. H.; Lee, Y. J.; Ryu, S. H.; Sung, N. Y.; Cha, M. K.; Nam, J. Y.; Park, J. Y.; Cho, E. R.; Ryu, T. H.

2011-12-01

Advanced Radiation Technology Institute is a government-supported institute for radiation research and application. It has focused on development of fundamentals for radiation applications based on the existing radiation technology, and on enhancement of biological effectiveness of radiation through theoretical approach to the combined actions of radiation with another factor. Application of radiation technology together with the existing technologies to enhance the physical, chemical, biological characteristics through modification of biomolecules resulted in creation of de novo materials of scientific and industrial values. A theoretical model for combined action of radiation with another physico-chemical factor has been established. Conclusively the results of this study can provide scientific bases for maximizing the efficacy of ionizing radiation in relation to industrial applications

Celecoxib enhances radiation response of secondary bone tumors of a human non-small cell lung cancer via antiangiogenesis in vivo

Energy Technology Data Exchange (ETDEWEB)

Klenke, Frank Michael [Bern Univ. (Switzerland). Dept. of Orthopedic Surgery; Abdollahi, Amir [Deutsches Krebsforschungszentrum, Heidelberg (Germany). Dept. of Radiation Oncology; Tufts Univ. School of Medicine, Boston, MA (United States). Center of Cancer Systems Biology; Bischof, Marc; Huber, Peter E. [Deutsches Krebsforschungszentrum, Heidelberg (Germany). Dept. of Radiation Oncology; Gebhard, Martha-Maria [Heidelberg Univ. (Germany). Dept. of Experimental Surgery; Ewerbeck, Volker [Heidelberg Univ. (Germany). Dept. of Orthopedic Surgery; Sckell, Axel [Charite Univ. Medical Center, Berlin (Germany). Dept. of Orthopedic, Trauma and Reconstructive Surgery

2011-01-15

Purpose: Cyclooxygenase-2 (COX-2) inhibitors mediate a systemic antitumor activity via antiangiogenesis and seem to enhance the response of primary tumors to radiation. Radiosensitizing effects of COX-2 inhibition have not been reported for bone metastases. Therefore, the aim of this study was the investigation of the radiosensitizing effects of the selective COX-2 inhibitor celecoxib in secondary bone tumors of a non-small cell lung carcinoma in vivo. Materials and Methods: Human A549 lung carcinomas were implanted into a cranial window preparation in male SCID mice (n = 24). Animals were treated with either celecoxib or radiation (7 Gy single photon dose) alone or a combination of celecoxib and radiation, respectively. Untreated animals served as controls. The impact of radiation and COX-2 inhibition on angiogenesis, microcirculation, and tumor growth was analyzed over 28 days by means of intravital microscopy and histological methods. Results: Monotherapies with radiation as well as celecoxib had significant antitumor effects compared to untreated controls. Both therapies reduced tumor growth and vascularization to a similar extent. The simultaneous administration of celecoxib and radiation further enhanced the antitumor and antiangiogenic effects of single-beam radiation. With the combined treatment approach, tumor vascularization and tumor size were decreased by 57% and 51%, respectively, as compared to monotherapy with radiation. Conclusion: The combined application of radiation therapy and COX-2 inhibition showed synergistic effects concerning the inhibition of tumor growth and tumor angiogenesis. Therefore, the combination of radiation with COX-2 inhibitor therapy represents a promising approach to improve the therapeutic efficacy of radiotherapy of bone metastases. (orig.)

Enhanced photodynamic efficacy of zinc phthalocyanine by conjugating to heptalysine.

Science.gov (United States)

Li, Linsen; Luo, Zhipu; Chen, Zhuo; Chen, Jincan; Zhou, Shanyong; Xu, Peng; Hu, Ping; Wang, Jundong; Chen, Naisheng; Huang, Jinling; Huang, Mingdong

2012-11-21

Zinc phthalocyanine (ZnPc) is a promising photosensitizer for photodynamic therapy, but faces some challenges: ZnPc is insoluble in water and thus requires either special formulation of ZnPc by, e.g., liposome or Cremophor EL, or chemical modification of Pc ring to enhance its bioavailability and photodynamic efficacy. Here, we conjugated monosubstituted ZnPc-COOH with a series of oligolysine moieties with different numbers of lysine residues (ZnPc-(Lys)(n) (n = 1, 3, 5, 7, 9) to improve the water solubility of the ZnPc conjugates. We measured the photosensitizing efficacies and the cellular uptakes of this series of conjugates on a normal and a cancerous cell line. In addition, we developed a sensitive in situ method to distinguish the difference in photodynamic efficacy among conjugates. Our results showed that ZnPc-(Lys)(7) has the highest photodynamic efficacy compared to the other conjugates investigated.

Enhanced natural radiation exposure enhanced by human activity: the largest contributor to the Chinese population dose

International Nuclear Information System (INIS)

Pan Ziqiang; Liu Yanyang

2011-01-01

For the radiation exposure caused by human activities, the enhanced natural radiation exposure is the largest contributor to Chinese population dose. This problem has attracted social attention in recent years. Efforts have been made in several fields, such as radon indoors and in workplace, environmental problems associated with NORMs, occupational radiation hazards of non-uranium mine, and radiation dose evaluation for energy chain, but there are still many problems to be solved. In order to protect the health of workers and the public, while ensuring industrial production and economic development, it is also necessary to continue to strengthen research in all aspects above mentioned, and gradually promote the control of natural radiation exposure enhanced by human activities. (authors)

Heat enhances radiation inhibition of wound healing

International Nuclear Information System (INIS)

Twomey, P.; Hill, S.; Joiner, M.; Hobson, B.; Denekamp, J.

1987-01-01

To study the effect of hyperthermia on the inhibition of healing by radiation, the authors used 2 models of wound tensile strength in mice. In one, tensile strength of 1 cm strips of wounded skin was measured. In the other, strength was measured on 2 by 1 by .3 cm surgical prosthetic sponges of polyvinyl alcohol which has been cut, resutured, and implanted subcutaneously. Granulation tissue grows into the pores of the sponges which gradually fill with collagen. Tensile strength in both models was measured on day 14 using a constant strain extensiometer. The wounds were given graduated doses of ortho-voltage radiation with or without hyperthermia. Maximum radiation sensitivity occurred during the period of rapid neovascularization in the first 5 days after wounding, when a loss of 80% in wound strength occurred with doses less than 20 gray. For single radiation doses given 48 hours after wounding, the authors found a steep dose-response curve with half maximum reduction in strength occurring in both models at approximately 10 gray. Hyperthermia was produced in two ways. Skin wounds were heated in a circulating water bath. In the sponge model, more uniform heating occurs with an RF generator scaled to the mouse. At a dose of 43 C for 30 minutes, no inhibition of healing by heat alone was found. However the combination of heat and radiation produced definite enhancement of radiation damage, with thermal enhancement ratios of up to 1.9 being observed

Targeting DNA double strand break repair with hyperthermia and DNA-PKcs inhibition to enhance the effect of radiation treatment.

Science.gov (United States)

van Oorschot, Bregje; Granata, Giovanna; Di Franco, Simone; Ten Cate, Rosemarie; Rodermond, Hans M; Todaro, Matilde; Medema, Jan Paul; Franken, Nicolaas A P

2016-10-04

Radiotherapy is based on the induction of lethal DNA damage, primarily DNA double-strand breaks (DSB). Efficient DSB repair via Non-Homologous End Joining or Homologous Recombination can therefore undermine the efficacy of radiotherapy. By suppressing DNA-DSB repair with hyperthermia (HT) and DNA-PKcs inhibitor NU7441 (DNA-PKcsi), we aim to enhance the effect of radiation.The sensitizing effect of HT for 1 hour at 42°C and DNA-PKcsi [1 μM] to radiation treatment was investigated in cervical and breast cancer cells, primary breast cancer sphere cells (BCSCs) enriched for cancer stem cells, and in an in vivo human tumor model. A significant radio-enhancement effect was observed for all cell types when DNA-PKcsi and HT were applied separately, and when both were combined, HT and DNA-PKcsi enhanced radio-sensitivity to an even greater extent. Strikingly, combined treatment resulted in significantly lower survival rates, 2 to 2.5 fold increase in apoptosis, more residual DNA-DSB 6 h post treatment and a G2-phase arrest. In addition, tumor growth analysis in vivo showed significant reduction in tumor growth and elevated caspase-3 activity when radiation was combined with HT and DNA-PKcsi compared to radiation alone. Importantly, no toxic side effects of HT or DNA-PKcsi were found.In conclusion, inhibiting DNA-DSB repair using HT and DNA-PKcsi before radiotherapy leads to enhanced cytotoxicity in cancer cells. This effect was even noticed in the more radio-resistant BCSCs, which are clearly sensitized by combined treatment. Therefore, the addition of HT and DNA-PKcsi to conventional radiotherapy is promising and might contribute to more efficient tumor control and patient outcome.

Enhancement of radiation damage in germinating wheat seeds by hyperthermia

International Nuclear Information System (INIS)

Guo Fangqing; Gu Ruiqi

1994-01-01

Enhancement of X-ray induced radiation damage in germinating wheat seeds by heat treatment (44 degree C or 41 degree C, 20 min) has been investigated. The enhancement effect of heat treatment after irradiation was more significant than that of heat treatment before irradiation at dose range of 4.3-8.6 Gy. It was observed that germinating wheat seeds were very sensitive to heat treatment within 15 min after irradiation, which indicated that the repair of radiation damage was very active and rapid in a short period after irradiation. The repair of radiation damage in interval of fractionated irradiation was severely inhibited by heat treatment. The sensitivity of seeds to heat treatment corresponded with the levels of their repair activities. The more active the repairs of the seeds are, the more sensitive to heat treatment the seeds show. It was assumed that the enhancement of radiation damage by heat treatment in germinating wheat seeds was attributed to the inhibition of radiation damage repair by heat treatment, which is similar to the results of animal experiments

OBSERVATIONS OF ENHANCED RADIATIVE GRAIN ALIGNMENT NEAR HD 97300

International Nuclear Information System (INIS)

Andersson, B-G; Potter, S. B.

2010-01-01

We have obtained optical multi-band polarimetry toward sightlines through the Chamaeleon I cloud, particularly in the vicinity of the young B9/A0 star HD 97300. We show, in agreement with earlier studies, that the radiation field impinging on the cloud in the projected vicinity of the star is dominated by the flux from the star, as evidenced by a local enhancement in the grain heating. By comparing the differential grain heating with the differential change in the location of the peak of the polarization curve, we show that the grain alignment is enhanced by the increase in the radiation field. We also find a weak, but measurable, variation in the grain alignment with the relative angle between the radiation field anisotropy and the magnetic field direction. Such an anisotropy in the grain alignment is consistent with a unique prediction of modern radiative alignment torque theory and provides direct support for radiatively driven grain alignment.

Studies on omnidirectional enhancement of giga-hertz radiation by sub-wavelength plasma modulation

Science.gov (United States)

Fanrong, KONG; Qiuyue, NIE; Shu, LIN; Zhibin, WANG; Bowen, LI; Shulei, ZHENG; Binhao, JIANG

2018-01-01

The technology of radio frequency (RF) radiation intensification for radio compact antennas based on modulation and enhancement effects of sub-wavelength plasma structures represents an innovative developing strategy. It exhibits important scientific significance and promising potential of broad applications in various areas of national strategic demands, such as electrical information network and microwave communication, detection and control technology. In this paper, laboratory experiments and corresponding analyses have been carried out to investigate the modulation and enhancement technology of sub-wavelength plasma structure on the RF electromagnetic radiation. An application focused sub-wavelength plasma-added intensification up to ∼7 dB higher than the free-space radiation is observed experimentally in giga-hertz (GHz) RF band. The effective radiation enhancement bandwidth covers from 0.85 to 1.17 GHz, while the enhanced electromagnetic signals transmitted by sub-wavelength plasma structures maintain good communication quality. Particularly, differing from the traditional RF electromagnetic radiation enhancement method characterized by focusing the radiation field of antenna in a specific direction, the sub-wavelength plasma-added intensification of the antenna radiation presents an omnidirectional enhancement, which is reported experimentally for the first time. Corresponding performance characteristics and enhancement mechanism analyses are also conducted in this paper. The results have demonstrated the feasibility and promising potential of sub-wavelength plasma modulation in application focused RF communication, and provided the scientific basis for further research and development of sub-wavelength plasma enhanced compact antennas with wide-range requests and good quality for communication.

The Gottingen Minipig Is a Model of the Hematopoietic Acute Radiation Syndrome: G-Colony Stimulating Factor Stimulates Hematopoiesis and Enhances Survival From Lethal Total-Body γ-Irradiation

Energy Technology Data Exchange (ETDEWEB)

Moroni, Maria, E-mail: maria.moroni@usuhs.edu [Radiation Countermeasures Program, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, Maryland (United States); Ngudiankama, Barbara F. [Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland (United States); Christensen, Christine [Division of Comparative Pathology, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, Maryland (United States); Olsen, Cara H. [Biostatistics Consulting Center, Uniformed Services University of the Health Sciences, Bethesda, Maryland (United States); Owens, Rossitsa [Radiation Countermeasures Program, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, Maryland (United States); Lombardini, Eric D. [Veterinary Medicine Department, Armed Forces Research Institute of Medical Sciences, Bangkok (Thailand); Holt, Rebecca K. [Veterinary Science Department, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, Maryland (United States); Whitnall, Mark H. [Radiation Countermeasures Program, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, Maryland (United States)

2013-08-01

Purpose: We are characterizing the Gottingen minipig as an additional large animal model for advanced drug testing for the acute radiation syndrome (ARS) to enhance the discovery and development of novel radiation countermeasures. Among the advantages provided by this model, the similarities to human hematologic parameters and dynamics of cell loss/recovery after irradiation provide a convenient means to compare the efficacy of drugs known to affect bone marrow cellularity and hematopoiesis. Methods and Materials: Male Gottingen minipigs, 4 to 5 months old and weighing 9 to 11 kg, were used for this study. We tested the standard off-label treatment for ARS, rhG-CSF (Neupogen, 10 μg/kg/day for 17 days), at the estimated LD70/30 total-body γ-irradiation (TBI) radiation dose for the hematopoietic syndrome, starting 24 hours after irradiation. Results: The results indicated that granulocyte colony stimulating factor (G-CSF) enhanced survival, stimulated recovery from neutropenia, and induced mobilization of hematopoietic progenitor cells. In addition, the administration of G-CSF resulted in maturation of monocytes/macrophages. Conclusions: These results support continuing efforts toward validation of the minipig as a large animal model for advanced testing of radiation countermeasures and characterization of the pathophysiology of ARS, and they suggest that the efficacy of G-CSF in improving survival after total body irradiation may involve mechanisms other than increasing the numbers of circulating granulocytes.

The Gottingen minipig is a model of the hematopoietic acute radiation syndrome: G-colony stimulating factor stimulates hematopoiesis and enhances survival from lethal total-body γ-irradiation.

Science.gov (United States)

Moroni, Maria; Ngudiankama, Barbara F; Christensen, Christine; Olsen, Cara H; Owens, Rossitsa; Lombardini, Eric D; Holt, Rebecca K; Whitnall, Mark H

2013-08-01

We are characterizing the Gottingen minipig as an additional large animal model for advanced drug testing for the acute radiation syndrome (ARS) to enhance the discovery and development of novel radiation countermeasures. Among the advantages provided by this model, the similarities to human hematologic parameters and dynamics of cell loss/recovery after irradiation provide a convenient means to compare the efficacy of drugs known to affect bone marrow cellularity and hematopoiesis. Male Gottingen minipigs, 4 to 5 months old and weighing 9 to 11 kg, were used for this study. We tested the standard off-label treatment for ARS, rhG-CSF (Neupogen, 10 μg/kg/day for 17 days), at the estimated LD70/30 total-body γ-irradiation (TBI) radiation dose for the hematopoietic syndrome, starting 24 hours after irradiation. The results indicated that granulocyte colony stimulating factor (G-CSF) enhanced survival, stimulated recovery from neutropenia, and induced mobilization of hematopoietic progenitor cells. In addition, the administration of G-CSF resulted in maturation of monocytes/macrophages. These results support continuing efforts toward validation of the minipig as a large animal model for advanced testing of radiation countermeasures and characterization of the pathophysiology of ARS, and they suggest that the efficacy of G-CSF in improving survival after total body irradiation may involve mechanisms other than increasing the numbers of circulating granulocytes. Published by Elsevier Inc.

The Gottingen Minipig Is a Model of the Hematopoietic Acute Radiation Syndrome: G-Colony Stimulating Factor Stimulates Hematopoiesis and Enhances Survival From Lethal Total-Body γ-Irradiation

International Nuclear Information System (INIS)

Moroni, Maria; Ngudiankama, Barbara F.; Christensen, Christine; Olsen, Cara H.; Owens, Rossitsa; Lombardini, Eric D.; Holt, Rebecca K.; Whitnall, Mark H.

2013-01-01

Purpose: We are characterizing the Gottingen minipig as an additional large animal model for advanced drug testing for the acute radiation syndrome (ARS) to enhance the discovery and development of novel radiation countermeasures. Among the advantages provided by this model, the similarities to human hematologic parameters and dynamics of cell loss/recovery after irradiation provide a convenient means to compare the efficacy of drugs known to affect bone marrow cellularity and hematopoiesis. Methods and Materials: Male Gottingen minipigs, 4 to 5 months old and weighing 9 to 11 kg, were used for this study. We tested the standard off-label treatment for ARS, rhG-CSF (Neupogen, 10 μg/kg/day for 17 days), at the estimated LD70/30 total-body γ-irradiation (TBI) radiation dose for the hematopoietic syndrome, starting 24 hours after irradiation. Results: The results indicated that granulocyte colony stimulating factor (G-CSF) enhanced survival, stimulated recovery from neutropenia, and induced mobilization of hematopoietic progenitor cells. In addition, the administration of G-CSF resulted in maturation of monocytes/macrophages. Conclusions: These results support continuing efforts toward validation of the minipig as a large animal model for advanced testing of radiation countermeasures and characterization of the pathophysiology of ARS, and they suggest that the efficacy of G-CSF in improving survival after total body irradiation may involve mechanisms other than increasing the numbers of circulating granulocytes

Enhanced escape rate for Hg 254 nm resonance radiation in fluorescent lamps

International Nuclear Information System (INIS)

Lawler, James E; Raizen, Mark G

2013-01-01

The potential of the low-cost MAGIS isotopic separation method to improve fluorescent lamp efficacy is explored using resonance radiation transport simulations. New Hg isotopic mixes are discovered that yield escape rates for 254 nm Hg I resonance radiation equal to 117% to 122% of the rate for a natural isotopic mix under the same lamp conditions. (paper)

Validation of an instrument for mathematics enhancement teaching efficacy of Pacific Northwest agricultural educators

Science.gov (United States)

Jansen, Daniel J.

Teacher efficacy continues to be an important area of study in educational research. This study tested an instrument designed to assess the perceived efficacy of agricultural education teachers when engaged in lessons involving mathematics instruction. The study population of Oregon and Washington agricultural educators utilized in the validation of the instrument revealed important demographic findings and specific results related to teacher efficacy for the study population. An instrument was developed from the assimilation of three scales previously used and validated in efficacy research. Participants' mathematics teaching efficacy was assessed using a portion of the Mathematics Teaching Efficacy Beliefs Instrument (MTEBI), and personal mathematics efficacy was evaluated by the mathematics self-belief instrument which was derived from the Betz and Hackett's Mathematics Self-Efficacy Scale. The final scale, the Teachers' Sense of Efficacy Scale (TSES) created by Tschannen-Moran and Woolfolk Hoy, examined perceived personal teaching efficacy. Structural equation modeling was used as the statistical analyses tool to validate the instrument and examine correlations between efficacy constructs used to determine potential professional development needs of the survey population. As part of the data required for validation of the Mathematics Enhancement Teaching Efficacy instrument, demographic information defining the population of Oregon and Washington agricultural educators was obtained and reported. A hypothetical model derived from teacher efficacy literature was found to be an acceptable model to verify construct validity and determine strength of correlations between the scales that defined the instrument. The instrument produced an alpha coefficient of .905 for reliability. Both exploratory and confirmatory factor analyses were used to verify construct and discriminate validity. Specifics results related to the survey population of agricultural educators

Clinical efficacy of radiation synovectomy in digital joint osteoarthritis

International Nuclear Information System (INIS)

Kampen, Willm Uwe; Hellweg, Leif; Massoudi-Nickel, Schirin; Czech, Norbert; Henze, Eberhard; Brenner, Winfried

2005-01-01

Radiation synovectomy was developed for local treatment of rheumatoid arthritis. In this study, the long-term efficacy of radiation synovectomy was retrospectively evaluated in patients with osteoarthritis (activated arthrosis) of the digital joints using an algofunctional score. Fifty-three digital joints in 29 patients (mean age 64.8 years) were treated by intra-articular injection of 169 Er citrate. All joints were painful despite pharmacotherapy and showed an elevated blood pool pattern in a pretherapeutic three-phase bone scan, indicative for local synovitis. The patients were asked to classify their complaints with respect to different daily manual activities on a ten-step pain scale from 1 (total disability) to 10 (lack of any impairment) prior to and after treatment, with a mean follow-up of 41 months. Local signs of osteoarthritis such as joint swelling or pain were additionally evaluated and were scored from progression of complaints to excellent improvement based on patient self-evaluation. All patients reported a pronounced improvement in their manual activities. The mean total score of 4.73±0.58 for all activities prior to treatment increased significantly to 6.79±0.47 after radiation synovectomy (p<0.05). The best results were obtained in the thumb base joints, whereas distal interphalangeal joints were frequently resistant to therapy. Radiation synovectomy is highly effective in digital joint osteoarthritis with concomitant local synovitis. (orig.)

Clinical efficacy of radiation synovectomy in digital joint osteoarthritis

Energy Technology Data Exchange (ETDEWEB)

Kampen, Willm Uwe; Hellweg, Leif; Massoudi-Nickel, Schirin; Czech, Norbert; Henze, Eberhard [University Hospital Schleswig-Holstein, Clinic of Nuclear Medicine, Kiel (Germany); Brenner, Winfried [University Hospital Hamburg-Eppendorf, Department of Nuclear Medicine (Germany)

2005-04-01

Radiation synovectomy was developed for local treatment of rheumatoid arthritis. In this study, the long-term efficacy of radiation synovectomy was retrospectively evaluated in patients with osteoarthritis (activated arthrosis) of the digital joints using an algofunctional score. Fifty-three digital joints in 29 patients (mean age 64.8 years) were treated by intra-articular injection of{sup 169}Er citrate. All joints were painful despite pharmacotherapy and showed an elevated blood pool pattern in a pretherapeutic three-phase bone scan, indicative for local synovitis. The patients were asked to classify their complaints with respect to different daily manual activities on a ten-step pain scale from 1 (total disability) to 10 (lack of any impairment) prior to and after treatment, with a mean follow-up of 41 months. Local signs of osteoarthritis such as joint swelling or pain were additionally evaluated and were scored from progression of complaints to excellent improvement based on patient self-evaluation. All patients reported a pronounced improvement in their manual activities. The mean total score of 4.73{+-}0.58 for all activities prior to treatment increased significantly to 6.79{+-}0.47 after radiation synovectomy (p<0.05). The best results were obtained in the thumb base joints, whereas distal interphalangeal joints were frequently resistant to therapy. Radiation synovectomy is highly effective in digital joint osteoarthritis with concomitant local synovitis. (orig.)

Enhancing radiative energy transfer through thermal extraction

Directory of Open Access Journals (Sweden)

Tan Yixuan

2016-06-01

Full Text Available Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a. In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics.

Recombinant, catalytically inactive juvenile hormone esterase enhances efficacy of baculovirus insecticides

NARCIS (Netherlands)

Meer, van M.M.M.; Bonning, B.C.; Ward, V.K.; Vlak, J.M.; Hammock, B.D.

2000-01-01

The insecticidal efficacy of baculoviruses can be enhanced by engineering the viral genome to express proteins that disrupt the physiology of the host insect. Here we describe the development of a genetically engineered Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) which expresses

Establishing a ultraviolet radiation observational network and enhancing the study on ultraviolet radiation

Science.gov (United States)

Bai, Jianhui; Wang, Gengchen

2003-09-01

On the basis of analyzing observational data on solar radiation, meteorological parameters, and total ozone amount for the period of January 1990 to December 1991 in the Beijing area, an empirical calculation method for ultraviolet radiation (UV) in clear sky is obtained. The results show that the calculated values agree well with the observed, with maximum relative bias of 6.2% and mean relative bias for 24 months of 1.9%. Good results are also obtained when this method is applied in Guangzhou and Mohe districts. The long-term variation of UV radiation in clear sky over the Beijing area from 1979 to 1998 is calculated, and the UV variation trends and causes are discussed: direct and indirect UV energy absorption by increasing pollutants in the troposphere may have caused the UV decrease in clear sky in the last 20 years. With the enhancement of people’s quality of life and awareness of health, it will be valuable and practical to provid UV forecasts for typical cities and rural areas. So, we should develop and enhance UV study in systematic monitoring, forecasting, and developing a good and feasible method for UV radiation reporting in China, especially for big cities.

Efficacy of Polaprezinc for Acute Radiation Proctitis in a Rat Model

International Nuclear Information System (INIS)

Doi, Hiroshi; Kamikonya, Norihiko; Takada, Yasuhiro; Fujiwara, Masayuki; Tsuboi, Keita; Inoue, Hiroyuki; Tanooka, Masao; Nakamura, Takeshi; Shikata, Toshiyuki; Tsujimura, Tohru; Hirota, Shozo

2011-01-01

Purpose: The purpose of the present study was to standardize the experimental rat model of radiation proctitis and to examine the efficacy of polaprezinc on radiation proctitis. Methods and Materials: A total of 54 female Wistar rats (5 weeks old) were used. The rats were divided into three groups: those treated with polaprezinc (PZ+), those treated with base alone, exclusive of polaprezinc (PZ-), and those treated without any medication (control). All the rats were irradiated to the rectum. Polaprezinc was prepared as an ointment. The ointment was administered rectally each day after irradiation. All rats were killed on the 10th day after irradiation. The mucosal changes were evaluated endoscopically and pathologically. The results were graded from 0 to 4 and compared according to milder or more severe status, as applicable. Results: According to the endoscopic findings, the proportion of mild changes in the PZ+, PZ-, and control group was 71.4%, 25.0%, and 14.3% respectively. On pathologic examination, the proportion of low-grade findings in the PZ+, PZ-, and control group was 80.0%, 58.3%, and 42.9% for mucosal damage, 85.0%, 41.7%, and 42.9% for a mild degree of inflammation, and 50.0%, 33.3%, and 4.8% for a shallow depth of inflammation, respectively. The PZ+ group tended to have milder mucosal damage than the other groups, according to all criteria used. In addition, significant differences were observed between the PZ+ and control groups regarding the endoscopic findings, degree of inflammation, and depth of inflammation. Conclusions: This model was confirmed to be a useful experimental rat model for radiation proctitis. The results of the present study have demonstrated the efficacy of polaprezinc against acute radiation-induced rectal disorders using the rat model.

Radiation degradation and the consequent decrease in the efficacy of some dilute chemical decontaminant formulations

Energy Technology Data Exchange (ETDEWEB)

Kamal Kishore; Dey, G.R.; Naik, D.B.; Moorthy, P.N. [Applied Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India)

1998-12-31

Constituents of dilute chemical decontaminant formulations such as ascorbic acid, EDTA, picolinic acid (PA) and 2,6-pyridine dicarboxylic acid (PDCA), also known as dipicolinic acid, are highly reactive with primary species produced from water radiolysis. Picolinic acid and PDCA however, are less sensitive to radiation dose due to their aromatic nature. They also help in protecting ascorbic acid when in a mixture. The efficacy for dissolution of magnetite was found to reduce drastically on irradiation in the case of EDTA/oxalic acid/citric acid while it was unaffected in the case of picolinic acid/ascorbic acid. In the case of EDTA/ascorbic acid/citric acid or PDCA/ascorbic acid formulations, there was only a marginal effect of radiation on the efficacy of the formulations. (author)

Enhanced killing of mammalian cells by radiation combined with m-AMSA

International Nuclear Information System (INIS)

Roberts, P.B.; Millar, B.C.

1980-01-01

m-AMSA is an intercalating agent at present on Phase II trial as a chemotherapeutic drug. A 30min exposure of Chinese hamster (Line V79-753B) cells to submicromolar concentrations of m-AMSA killed 50% of the cells. The survivors had an enhanced sensitivity to radiation-induced cell killing. Depending upon the conditions, m-AMSA enhanced the radiation effect by either a decrease in the survival-curve shoulder or by an increase in slope. m-AMSA may act partly by suppressing the accumulation of sublethal damage but, if so, recovery from damage as measured in split-dose experiments with cells pretreated with the drug is not affected. m-AMSA increased radiation lethality throughout the cell cycle, but a contribution to its radiation effect from selective toxicity to cells in a radioresistant phase of the cell cycle cannot be excluded. Radiation and the drug interacted to give increased cell killing, even when the exposures to each agent were separated in time. It is concluded that m-ASMA may behave like actinomycin D and adriamycin, and enhance clinical radiation responses. In vivo testing to determine the effect of m-AMSA on the therapeutic index is recommended. (author)

Enhanced killing of mammalian cells by radiation combined with m-AMSA

Energy Technology Data Exchange (ETDEWEB)

Roberts, P B; Millar, B C [Institute of Cancer Research, Sutton (UK). Surrey Branch

1980-11-01

m-AMSA is an intercalating agent at present on Phase II trial as a chemotherapeutic drug. A 30 min exposure of Chinese hamster (Line V79-753B) cells to submicromolar concentrations of m-AMSA killed 50% of the cells. The survivors had an enhanced sensitivity to radiation-induced cell killing. Depending upon the conditions, m-AMSA enhanced the radiation effect by either a decrease in the survival-curve shoulder or by an increase in slope. m-AMSA may act partly by suppressing the accumulation of sublethal damage but, if so, recovery from damage as measured in split-dose experiments with cells pretreated with the drug is not affected. m-AMSA increased radiation lethality throughout the cell cycle, but a contribution to its radiation effect from selective toxicity to cells in a radioresistant phase of the cell cycle cannot be excluded. Radiation and the drug interacted to give increased cell killing, even when the exposures to each agent were separated in time. It is concluded that m-ASMA may behave like actinomycin D and adriamycin, and enhance clinical radiation responses. In vivo testing to determine the effect of m-AMSA on the therapeutic index is recommended.

Enhancement of the efficacy of x-irradiation by pentobarbital in a rodent brain-tumor model

International Nuclear Information System (INIS)

Olson, J.J.; Friedman, R.; Orr, K.; Delaney, T.; Oldfield, E.H.

1990-01-01

Radiation therapy is an important component of brain tumor treatment, but its efficacy is limited by its toxicity to the surrounding normal tissue. Pentobarbital acts as a cerebral radioprotectant, but the selectivity of its protection for the central nervous system has not been demonstrated. To determine if pentobarbital also protects tumor against ionizing radiation, five groups of Fischer 344 rats were observed after exposure to varying combinations of the presence or absence of implanted tumor, pentobarbital, and radiation treatment. The first three groups underwent cerebral implantations of a suspension of 9L gliosarcoma cells. Group 1 was left untreated and served as tumor-bearing controls. Group 2 received 30 Gy of whole-brain x-irradiation without anesthesia 8 days after tumor implantation. Group 3 received the same radiation treatment 15 minutes after pretreatment with 60 mg/kg of pentobarbital intraperitoneally. Groups 4 and 5 served as radiation controls, receiving 30 Gy of x-irradiation while awake and 30 Gy of x-irradiation after pentobarbital administration, respectively. Survival was calculated from the death of the last tumor-bearing rat. The mean survival time in tumor-bearing control rats was 20.8 +/- 2.6 days (+/- standard deviation). X-irradiation alone significantly enhanced the period of survival in rats implanted with the 9L tumor (29.7 +/- 5.6 days, p less than 0.03). Further significant prolongation of survival was seen with the addition of pentobarbital to the treatment regimen (39.9 +/- 13.5 days, p less than 0.01). Nontumor-bearing rats irradiated while awake (Group 4) survived 30.9 +/- 2.3 days. All of their pentobarbital-anesthetized counterparts in Group 5 survived. If pentobarbital had offered radioprotection to the tumor, then Group 3 would have had a shorter survival period than Group 2

Effects of estrogen antagonists on estradiol-enhanced radiation transformation in vitro

International Nuclear Information System (INIS)

Umans, R.S.; Kenneddy, A.R.

1988-01-01

We have previously reported that radiation and 17β-estrediol can induce transformation in vitro in C3H 10T1/2 cells. In the present series of experiments, we have observed that antagonists of estrogen action, such as c-AMP activating agents(Theophylinne and dibutylc-AMP) and the antiestrogens tamoxifen, suppress radiation/17β-estradiol enhanced transformation in vitro. None of these known estrogen antagonists had a significant effect on transformation induced by radiation alone. Our results with added dibutyl c-AMP, theophylline and tamoxifen suggest that estrogen receptor complex formation may play a role in estrogen-enhanced radiation transformation in vitro (author)

Osmotic Compounds Enhance Antibiotic Efficacy against Acinetobacter baumannii Biofilm Communities.

Science.gov (United States)

Falghoush, Azeza; Beyenal, Haluk; Besser, Thomas E; Omsland, Anders; Call, Douglas R

2017-10-01

Biofilm-associated infections are a clinical challenge, in part because a hydrated matrix protects the bacterial community from antibiotics. Herein, we evaluated how different osmotic compounds (maltodextrin, sucrose, and polyethylene glycol [PEG]) enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities. Established (24-h) test tube biofilms (strain ATCC 17978) were treated with osmotic compounds in the presence or absence of 10× the MIC of different antibiotics (50 μg/ml tobramycin, 20 μg/ml ciprofloxacin, 300 μg/ml chloramphenicol, 30 μg/ml nalidixic acid, or 100 μg/ml erythromycin). Combining antibiotics with hypertonic concentrations of the osmotic compounds for 24 h reduced the number of biofilm bacteria by 5 to 7 log ( P baumannii strains were similarly treated with 400-Da PEG and tobramycin, resulting in a mean 2.7-log reduction in recoverable bacteria compared with tobramycin treatment alone. Multivariate regression models with data from different osmotic compounds and nine antibiotics demonstrated that the benefit from combining hypertonic treatments with antibiotics is a function of antibiotic mass and lipophilicity ( r 2 > 0.82; P baumannii and Escherichia coli K-12. Augmenting topical antibiotic therapies with a low-mass hypertonic treatment may enhance the efficacy of antibiotics against wound biofilms, particularly when using low-mass hydrophilic antibiotics. IMPORTANCE Biofilms form a barrier that protects bacteria from environmental insults, including exposure to antibiotics. We demonstrated that multiple osmotic compounds can enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities, but viscosity is a limiting factor, and the most effective compounds have lower molecular mass. The synergism between osmotic compounds and antibiotics is also dependent on the hydrophobicity and mass of the antibiotics. The statistical models presented herein provide a basis for predicting the optimal combination of

Dose enhancement effects of X ray radiation in bipolar transistors

International Nuclear Information System (INIS)

Chen Panxun

1997-01-01

The author has presented behaviour degradation and dose enhancement effects of bipolar transistors in X ray irradiation environment. The relative dose enhancement factors of X ray radiation were measured in bipolar transistors by the experiment methods. The mechanism of bipolar device dose enhancement was investigated

Enhancing the efficacy of entomopathogenic nematodes by gamma radiation in controlling Spodoptera littoralis larvae

Directory of Open Access Journals (Sweden)

R.M. Sayed

2017-04-01

Full Text Available Nowadays, finding a safe control program is the aim of all researchers. The goal of this work is to investigate the effect of gamma radiation on the Entomopathogenic nematodes, Steinernema scapterisci and Heterorhabditis bacteriophora Poinar (HP88 efficacy were tested against larvae of cotton leaf worm, Spodoptera littoralis (Boisd. under laboratory conditions. Results showed that 2 Gy irradiated S. scapterisci and H. bacteriophora were substantially effective in controlling S. littoralis larvae, while H. bacteriophora was more potent in controlling insect larvae. The results revealed that total protein concentration was significantly decreased (P < 0.05 after treatment with normal or irradiated H. bacteriophora or S. scapterisci. In addition, larvae infected with normal S. scapterisci or H. bacteriophora showed a significant elevation in phenoloxidase activity and represented significant reduce after treatment with 2 Gy irradiated S. scapterisci or H. bacteriophora as compared to control group. Also, lysozyme activity was significantly decreased after treatment with irradiated H. bacteriophora, but there was no significance with irradiated S. scapterisci, when compared with control. LDH activity was significantly high (p<0.05 in the haemolymph of larvae treated with normal or irradiated H. bacteriophora or S. scapterisci, as compared to control group. Furthermore among all treatments, 2 Gy irradiated H. bacteriophora was the most potent and efficient in the biomarkers changes. Therefore, it could be concluded that 2 Gy irradiated S. scapterisci and H. bacteriophora can serve within an integrated pest management (IPM program in an agroecosystem.

Theranostic Nanoseeds for Efficacious Internal Radiation Therapy of Unresectable Solid Tumors

Science.gov (United States)

Moeendarbari, Sina; Tekade, Rakesh; Mulgaonkar, Aditi; Christensen, Preston; Ramezani, Saleh; Hassan, Gedaa; Jiang, Ruiqian; Öz, Orhan K.; Hao, Yaowu; Sun, Xiankai

2016-02-01

Malignant tumors are considered “unresectable” if they are adhere to vital structures or the surgery would cause irreversible damages to the patients. Though a variety of cytotoxic drugs and radiation therapies are currently available in clinical practice to treat such tumor masses, these therapeutic modalities are always associated with substantial side effects. Here, we report an injectable nanoparticle-based internal radiation source that potentially offers more efficacious treatment of unresectable solid tumors without significant adverse side effects. Using a highly efficient incorporation procedure, palladium-103, a brachytherapy radioisotope in clinical practice, was coated to monodispersed hollow gold nanoparticles with a diameter about 120 nm, to form 103Pd@Au nanoseeds. The therapeutic efficacy of 103Pd@Au nanoseeds were assessed when intratumorally injected into a prostate cancer xenograft model. Five weeks after a single-dose treatment, a significant tumor burden reduction (>80%) was observed without noticeable side effects on the liver, spleen and other organs. Impressively, >95% nanoseeds were retained inside the tumors as monitored by Single Photon Emission Computed Tomography (SPECT) with the gamma emissions of 103Pd. These findings show that this nanoseed-based brachytherapy has the potential to provide a theranostic solution to unresectable solid tumors.

Radiation-induced enhancement of enzymatic cell lysis of Micrococcus radiodurans

International Nuclear Information System (INIS)

Watanabe, H.; Takehisa, M.; Iizuka, H.

1981-01-01

The intact cells of M. radiodurans were rendered sensitive to the action of lytic enzyme (P2-2 enzyme) by irradiation. The radiation-induced enhancement of cell lysis with P2-2 enzyme was completely prevented by the addition of t-butanol and irradiation at liquid nitrogen temperature. These results indicate that the enhancement is due to indirect action resulting from OH radicals. Cell lysis by lysozyme was enhanced only when the cells were irradiated under N 2 O. The enhancement of cell lysis with lysozyme was also prevented by adding alcohols. On the other hand, when lipid components in cells were removed by extraction with n-butanol, the radiation-induced enhancement of cell lysis with P2-2 enzyme and lysozyme was not observed. From these results it is concluded that the enhancement of enzymatic cell lysis by irradiation is attributable to alteration in the lipid-rich layer of the cell wall caused by OH radicals

Radiation-induced enhancement of enzymatic cell lysis of Micrococcus radiodurans

Energy Technology Data Exchange (ETDEWEB)

Watanabe, H.; Takehisa, M. [Japan Atomic Energy Research Inst., Takasaki, Gunma, Takasaki Radiation Chemistry Research Establishment (Japan); Iizuka, H.

1981-10-15

The intact cells of M. radiodurans were rendered sensitive to the action of lytic enzyme (P2-2 enzyme) by irradiation. The radiation-induced enhancement of cell lysis with P2-2 enzyme was completely prevented by the addition of t-butanol and irradiation at liquid nitrogen temperature. These results indicate that the enhancement is due to indirect action resulting from OH radicals. Cell lysis by lysozyme was enhanced only when the cells were irradiated under N{sub 2}O. The enhancement of cell lysis with lysozyme was also prevented by adding alcohols. On the other hand, when lipid components in cells were removed by extraction with n-butanol, the radiation-induced enhancement of cell lysis with P2-2 enzyme and lysozyme was not observed. From these results it is concluded that the enhancement of enzymatic cell lysis by irradiation is attributable to alteration in the lipid-rich layer of the cell wall caused by OH radicals.

UV Irradiance Enhancements by Scattering of Solar Radiation from Clouds

Directory of Open Access Journals (Sweden)

Uwe Feister

2015-08-01

Full Text Available Scattering of solar radiation by clouds can reduce or enhance solar global irradiance compared to cloudless-sky irradiance at the Earth’s surface. Cloud effects to global irradiance can be described by Cloud Modification Factors (CMF. Depending on strength and duration, irradiance enhancements affect the energy balance of the surface and gain of solar power for electric energy generation. In the ultraviolet region, they increase the risk for damage to living organisms. Wavelength-dependent CMFs have been shown to reach 1.5 even in the UV-B region at low altitudes. Ground-based solar radiation measurements in the high Andes region at altitudes up to 5917 m a.s.l showed cloud-induced irradiance enhancements. While UV-A enhancements were explained by cloud scattering, both radiation scattering from clouds and Negative Ozone Anomalies (NOA have been discussed to have caused short-time enhancement of UV-B irradiance. Based on scenarios using published CMF and additional spectroradiometric measurements at a low-altitude site, the contribution of cloud scattering to the UV-B irradiance enhancement in the Andes region has been estimated. The range of UV index estimates converted from measured UV-B and UV-A irradiance and modeled cloudless-sky ratios UV-B/erythemal UV is compatible with an earlier estimate of an extreme UV index value of 43 derived for the high Andes.

Nanodiamonds enhance therapeutic efficacy of doxorubicin in treating metastatic hormone-refractory prostate cancer.

Science.gov (United States)

Salaam, Amanee D; Hwang, Patrick T J; Poonawalla, Aliza; Green, Hadiyah N; Jun, Ho-wook; Dean, Derrick

2014-10-24

Enhancing therapeutic efficacy is essential for successful treatment of chemoresistant cancers such as metastatic hormone-refractory prostate cancer (HRPC). To improve the efficacy of doxorubicin (DOX) for treating chemoresistant disease, the feasibility of using nanodiamond (ND) particles was investigated. Utilizing the pH responsive properties of ND, a novel protocol for complexing NDs and DOX was developed using a pH 8.5 coupling buffer. The DOX loading efficiency, loading on the NDs, and pH responsive release characteristics were determined utilizing UV-Visible spectroscopy. The effects of the ND-DOX on HRPC cell line PC3 were evaluated with MTS and live/dead cell viability assays. ND-DOX displayed exceptional loading efficiency (95.7%) and drug loading on NDs (23.9 wt%) with optimal release at pH 4 (80%). In comparison to treatment with DOX alone, cell death significantly increased when cells were treated with ND-DOX complexes demonstrating a 50% improvement in DOX efficacy. Of the tested treatments, ND-DOX with 2.4 μg mL(-1) DOX exhibited superior efficacy (60% cell death). ND-DOX with 1.2 μg mL(-1) DOX achieved 42% cell death, which was comparable to cell death in response to 2.4 μg mL(-1) of free DOX, suggesting that NDs aid in decreasing the DOX dose necessary to achieve a chemotherapeutic efficacy. Due to its enhanced efficacy, ND-DOX can be used to successfully treat HRPC and potentially decrease the clinical side effects of DOX.

Ethacrynic acid: a novel radiation enhancer in human carcinoma cells

International Nuclear Information System (INIS)

Khil, Mark S.; Sang, Hie Kim; Pinto, John T.; Jae, Ho Kim

1996-01-01

Purpose: Because agents that interfere with thiol metabolism and glutathione S-transferase (GST) functions have been shown to enhance antitumor effects of alkylating agents in vitro and in vivo, the present study was conceived on the basis that an inhibitor of GST would enhance the radiation response of some selected human carcinoma cells. Ethacrynic acid (EA) was chosen for the study because it is an effective inhibitor of GST and is a well known diuretic in humans. Methods and Materials: Experiments were carried out with well-established human tumor cells in culture growing in Eagle's minimum essential medium (MEM) supplemented with 10% fetal calf serum (FCS). Cell lines used were MCF-7, MCF-7 adriamycin resistant (AR) cells (breast carcinoma), HT-29 cells (colon carcinoma), DU-145 cells (prostate carcinoma), and U-373 cells (malignant glioma). Cell survival following the exposure of cells to drug alone, radiation alone, and a combined treatment was assayed by determining the colony-forming ability of single plated cells in culture to obtain dose-survival curves. The drug enhancement ratio was correlated with levels of GST. Results: The cytotoxicity of EA was most pronounced in MCF-7, U-373, and DU-145 cells compared to MCF-7 AR and HT-29 cells. The levels of GST activity were found to be lower in those EA-sensitive cells. A significant radiation enhancement was obtained with EA-sensitive cells exposed to nontoxic concentrations of the drug immediately before or after irradiation. The sensitizer enhancement ratio (SER) of MCF-7 cells was 1.55 with EA (20 μg/ml), while the SER of MCF-7 AR was less than 1.1. Based on five different human tumor cells, a clear inverse relationship was demonstrated between the magnitude of SER and GST levels of tumor cells prior to the combined treatment. Conclusion: The present results suggest that EA, which acts as both a reversible and irreversible inhibitor of GST activity, could significantly enhance the radiation response of

Does Maternal HIV Disclosure Self-Efficacy Enhance Parent-Child Relationships and Child Adjustment?

Science.gov (United States)

Armistead, Lisa; Goodrum, Nada; Schulte, Marya; Marelich, William; LeCroix, Rebecca; Murphy, Debra A

2018-02-09

Nondisclosure of maternal HIV status to young children can negatively impact child functioning; however, many mothers do not disclose due to lack of self-efficacy for the disclosure process. This study examines demographic variations in disclosure self-efficacy, regardless of intention to disclose, and assesses the relationship between self-efficacy and child adjustment via the parent-child relationship among a sample of HIV+ mothers and their healthy children (N = 181 pairs). Mothers completed demographic and self-efficacy measures; children completed measures assessing the parent-child relationship and child adjustment (i.e., worry, self-concept, depression). Across demographics, few mothers reported confidence in disclosure. Results from covariance structural modeling showed mothers endorsing higher self-efficacy had children who reported better relationship quality, and, in turn, reported fewer adjustment difficulties; higher levels of disclosure self-efficacy also directly predicted fewer adjustment problems. Findings offer support for interventions aimed at providing mothers with skills to enhance confidence for disclosing their HIV status.

Enhancing Self-Efficacy and Performance: An Experimental Comparison of Psychological Techniques

Science.gov (United States)

Wright, Bradley James; O'Halloran, Paul Daniel; Stukas, Arthur Anthony

2016-01-01

Purpose: We assessed how 6 psychological performance enhancement techniques (PETs) differentially improved self-efficacy (SE) and skill performance. We also assessed whether vicarious experiences and verbal persuasion as posited sources of SE (Bandura, 1982) were supported and, further, if the effects of the 6 PETs remained after controlling for…

Effect of enhanced UV-B radiation on yield and quality of rice

International Nuclear Information System (INIS)

Yin Hong; Guo Wei; Mao Xiaoyan

2009-01-01

The effects of enhanced UV-B radiation on yield and quality of two rice cuhivars(ShenNong 6014 and ShenNong 265) are studied in potted method. There were three treatments including natural light (TCK), enhanced 5% UV-B radiation (T) and enhanced 10% (T). The results showed that enhanced UV-B radiation decreases yield components, the percentage of brown rice (0.66%-7.06%), head rice rate (5.65%-18.88%), the rate of white rice (22.17%-40.16%), grain area (2.61%-6.25%), fatty acid contents (1.23%-54.19%) and eating quality (1.07%-16.78%) but increasea protein content (4.65%-10.71%) and amylose content of rice (0.56%-4.81%). The effects of T2 was stronger than T1

Radiation enhanced conduction in insulators: computer modelling

International Nuclear Information System (INIS)

Fisher, A.J.

1986-10-01

The report describes the implementation of the Klaffky-Rose-Goland-Dienes [Phys. Rev. B.21 3610,1980] model of radiation-enhanced conduction and describes the codes used. The approach is demonstrated for the data for alumina of Pells, Buckley, Hill and Murphy [AERE R.11715, 1985]. (author)

A dynamical systems model for combinatorial cancer therapy enhances oncolytic adenovirus efficacy by MEK-inhibition.

Science.gov (United States)

Bagheri, Neda; Shiina, Marisa; Lauffenburger, Douglas A; Korn, W Michael

2011-02-01

Oncolytic adenoviruses, such as ONYX-015, have been tested in clinical trials for currently untreatable tumors, but have yet to demonstrate adequate therapeutic efficacy. The extent to which viruses infect targeted cells determines the efficacy of this approach but many tumors down-regulate the Coxsackievirus and Adenovirus Receptor (CAR), rendering them less susceptible to infection. Disrupting MAPK pathway signaling by pharmacological inhibition of MEK up-regulates CAR expression, offering possible enhanced adenovirus infection. MEK inhibition, however, interferes with adenovirus replication due to resulting G1-phase cell cycle arrest. Therefore, enhanced efficacy will depend on treatment protocols that productively balance these competing effects. Predictive understanding of how to attain and enhance therapeutic efficacy of combinatorial treatment is difficult since the effects of MEK inhibitors, in conjunction with adenovirus/cell interactions, are complex nonlinear dynamic processes. We investigated combinatorial treatment strategies using a mathematical model that predicts the impact of MEK inhibition on tumor cell proliferation, ONYX-015 infection, and oncolysis. Specifically, we fit a nonlinear differential equation system to dedicated experimental data and analyzed the resulting simulations for favorable treatment strategies. Simulations predicted enhanced combinatorial therapy when both treatments were applied simultaneously; we successfully validated these predictions in an ensuing explicit test study. Further analysis revealed that a CAR-independent mechanism may be responsible for amplified virus production and cell death. We conclude that integrated computational and experimental analysis of combinatorial therapy provides a useful means to identify treatment/infection protocols that yield clinically significant oncolysis. Enhanced oncolytic therapy has the potential to dramatically improve non-surgical cancer treatment, especially in locally advanced

Monte Carlo and analytic simulations in nanoparticle-enhanced radiation therapy

Directory of Open Access Journals (Sweden)

Paro AD

2016-09-01

Full Text Available Autumn D Paro,1 Mainul Hossain,2 Thomas J Webster,1,3,4 Ming Su1,4 1Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 2NanoScience Technology Center and School of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida, USA; 3Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia; 4Wenzhou Institute of Biomaterials and Engineering, Chinese Academy of Science, Wenzhou Medical University, Zhejiang, People’s Republic of China Abstract: Analytical and Monte Carlo simulations have been used to predict dose enhancement factors in nanoparticle-enhanced X-ray radiation therapy. Both simulations predict an increase in dose enhancement in the presence of nanoparticles, but the two methods predict different levels of enhancement over the studied energy, nanoparticle materials, and concentration regime for several reasons. The Monte Carlo simulation calculates energy deposited by electrons and photons, while the analytical one only calculates energy deposited by source photons and photoelectrons; the Monte Carlo simulation accounts for electron–hole recombination, while the analytical one does not; and the Monte Carlo simulation randomly samples photon or electron path and accounts for particle interactions, while the analytical simulation assumes a linear trajectory. This study demonstrates that the Monte Carlo simulation will be a better choice to evaluate dose enhancement with nanoparticles in radiation therapy. Keywords: nanoparticle, dose enhancement, Monte Carlo simulation, analytical simulation, radiation therapy, tumor cell, X-ray 

Biological Research for Radiation Protection

International Nuclear Information System (INIS)

Kim, In Gyu; Kim, Kug Chan; Jung, Il Lae; Choi, Yong Ho; Kim, Jin Sik; Moon, Myung Sook; Byun, Hee Sun; Phyo, Ki Heon; Kim, Sung Keun

2005-04-01

The work scope of 'Biological Research for the Radiation Protection' had contained the research about ornithine decarboxylase and its controlling proteins, thioredoxin, peroxiredoxin, S-adenosymethionine decarboxylase, and glutamate decarboxylase 67KD effect on the cell death triggered ionizing radiation and H 2 O 2 (toxic agents). In this study, to elucidate the role of these proteins in the ionizing radiation (or H 2 O 2 )-induced apoptotic cell death, we utilized sensesed (or antisensed) cells, which overexpress (or down-regulate) RNAs associated with these proteins biosynthesis, and investigated the effects of these genes on the cytotoxicity caused by ionizing radiation and H 2 O 2 (or paraquat). We also investigated whether genisteine(or thiamine) may enhance the cytotoxic efficacy of tumor cells caused by ionizing radiation (may enhance the preventing effect radiation or paraquat-induced damage) because such compounds are able to potentiate the cell-killing or cell protecting effects. Based on the above result, we suggest that the express regulation of theses genes have potentially importance for sensitizing the efficiency of radiation therapy of cancer or for protecting the radiation-induced damage of normal cells

Low and high linear energy transfer radiation sensitization of HCC cells by metformin

International Nuclear Information System (INIS)

Kim, Eun Ho; Jung, Won-Gyun; Kim, Mi-Sook; Cho, Chul-Koo; Jeong, Youn Kyoung; Jeong, Jae-Hoon

2014-01-01

The purpose of this study was to investigate the efficacy of metformin as a radiosensitizer for use in combination therapy for human hepatocellular carcinoma (HCC). Three human HCC cell lines (Huh7, HepG2, Hep3B) and a normal human hepatocyte cell line were treated with metformin alone or with radiation followed by metformin. In vitro tests were evaluated by clonogenic survival assay, FACS analysis, western blotting, immunofluorescence and comet assay. Metformin significantly enhanced radiation efficacy under high and low Linear Energy Transfer (LET) radiation conditions in vitro. In combination with radiation, metformin abrogated G2/M arrest and increased the cell population in the sub-G1 phase and the ROS level, ultimately increasing HCC cellular apoptosis. Metformin inhibits the repair of DNA damage caused by radiation. The radiosensitizing effects of metformin are much higher in neutron (high LET)-irradiated cell lines than in γ (low LET)-irradiated cell lines. Metformin only had a moderate effect in normal hepatocytes. Metformin enhances the radiosensitivity of HCC, suggesting it may have clinical utility in combination cancer treatment with high-LET radiation. (author)

Radiation demineralised bone enhanced osteoinductive capacity after transplantation

International Nuclear Information System (INIS)

Phillips, G.O.; Al-Assaf, S.; Williams, P.A.; Plessis, A. du; Yim, C.J.

2007-01-01

Using a mediating alkyne gas during the radiation treatment prevents the degradation of natural and synthetic polysaccharides and proteins. The product has higher viscosity and is more elastic than the original material and, therefore, gives enhanced functionality. Protein, within demineralised bone, too can be modified to give enhanced osteoinductive capacity after transplantation. Thus new functionalities can be achieved from the new products produced in food and medical products

Plasmonically enhanced thermomechanical detection of infrared radiation.

Science.gov (United States)

Yi, Fei; Zhu, Hai; Reed, Jason C; Cubukcu, Ertugrul

2013-04-10

Nanoplasmonics has been an attractive area of research due to its ability to localize and manipulate freely propagating radiation on the nanometer scale for strong light-matter interactions. Meanwhile, nanomechanics has set records in the sensing of mass, force, and displacement. In this work, we report efficient coupling between infrared radiation and nanomechanical resonators through nanoantenna enhanced thermoplasmonic effects. Using efficient conversion of electromagnetic energy to mechanical energy in this plasmo-thermomechanical platform with a nanoslot plasmonic absorber integrated directly on a nanobeam mechanical resonator, we demonstrate room-temperature detection of nanowatt level power fluctuations in infrared radiation. We expect our approach, which combines nanoplasmonics with nanomechanical resonators, to lead to optically controlled nanomechanical systems enabling unprecedented functionality in biomolecular and toxic gas sensing and on-chip mass spectroscopy.

Characterization of liver metastases: the efficacy of biphasic magnetic resonance imaging with ferucarbotran-enhancement

International Nuclear Information System (INIS)

Hong, H.S.; Byun, J.H.; Won, H.J.; Kim, K.W.; Lee, S.S.; Lee, M.G.; Yun, S.C.

2010-01-01

Aim: To retrospectively evaluate the efficacy of biphasic magnetic resonance imaging (MRI) of the liver with ferucarbotran-enhancement for the characterization of hepatic metastases. Materials and methods: Thirty-six patients underwent MRI of the liver with separate acquisition of double-contrast enhancement consisting of gadolinium and ferucarbotran. A total of 106 focal hepatic lesions (51 metastases, 31 cysts, 23 haemangiomas, and one eosinophilic abscess) were included. Two sets of MRI were analysed: (1) ferucarbotran set: ferucarbotran-enhanced T1-weighted (T1W) dynamic imaging combined with ferucarbotran-enhanced T2*-weighted (T2*W) delayed imaging and (2) double set: gadolinium-enhanced T1W dynamic imaging combined with ferucarbotran-enhanced T2*W delayed imaging. The diagnostic accuracy of the two sets was evaluated using alternative free-response receiver operating characteristic curve analysis. Sensitivity and specificity were compared using the McNemar test. The enhancement pattern of focal hepatic lesions was analysed on gadolinium and ferucarbotran-enhanced T1W dynamic imaging. Results: There was no significant difference in the accuracy of characterizing hepatic metastases between the two sets. Sensitivity and specificity were not significantly different between the sets (p > 0.05). Peripheral rim enhancement was exhibited in 57% of metastatic lesions on ferucarbotran-enhanced T1W dynamic imaging. The majority (96%) of hepatic haemangiomas demonstrated typical peripheral nodular enhancement with progression on ferucarbotran-enhanced T1W dynamic imaging and were easily differentiated from metastases. Conclusion: Biphasic MRI of the liver with ferucarbotran-enhancement alone provided comparable diagnostic efficacy to double-contrast MRI for the characterization of hepatic metastases.

Combinations of Radiation Therapy and Immunotherapy for Melanoma: A Review of Clinical Outcomes

International Nuclear Information System (INIS)

Barker, Christopher A.; Postow, Michael A.

2014-01-01

Radiation therapy has long played a role in the management of melanoma. Recent advances have also demonstrated the efficacy of immunotherapy in the treatment of melanoma. Preclinical data suggest a biologic interaction between radiation therapy and immunotherapy. Several clinical studies corroborate these findings. This review will summarize the outcomes of studies reporting on patients with melanoma treated with a combination of radiation therapy and immunotherapy. Vaccine therapies often use irradiated melanoma cells, and may be enhanced by radiation therapy. The cytokines interferon-α and interleukin-2 have been combined with radiation therapy in several small studies, with some evidence suggesting increased toxicity and/or efficacy. Ipilimumab, a monoclonal antibody which blocks cytotoxic T-lymphocyte antigen-4, has been combined with radiation therapy in several notable case studies and series. Finally, pilot studies of adoptive cell transfer have suggested that radiation therapy may improve the efficacy of treatment. The review will demonstrate that the combination of radiation therapy and immunotherapy has been reported in several notable case studies, series and clinical trials. These clinical results suggest interaction and the need for further study

Combinations of Radiation Therapy and Immunotherapy for Melanoma: A Review of Clinical Outcomes

Energy Technology Data Exchange (ETDEWEB)

Barker, Christopher A., E-mail: barkerc@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Postow, Michael A. [Department of Medicine, Melanoma and Sarcoma Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

2014-04-01

Radiation therapy has long played a role in the management of melanoma. Recent advances have also demonstrated the efficacy of immunotherapy in the treatment of melanoma. Preclinical data suggest a biologic interaction between radiation therapy and immunotherapy. Several clinical studies corroborate these findings. This review will summarize the outcomes of studies reporting on patients with melanoma treated with a combination of radiation therapy and immunotherapy. Vaccine therapies often use irradiated melanoma cells, and may be enhanced by radiation therapy. The cytokines interferon-α and interleukin-2 have been combined with radiation therapy in several small studies, with some evidence suggesting increased toxicity and/or efficacy. Ipilimumab, a monoclonal antibody which blocks cytotoxic T-lymphocyte antigen-4, has been combined with radiation therapy in several notable case studies and series. Finally, pilot studies of adoptive cell transfer have suggested that radiation therapy may improve the efficacy of treatment. The review will demonstrate that the combination of radiation therapy and immunotherapy has been reported in several notable case studies, series and clinical trials. These clinical results suggest interaction and the need for further study.

Manipulation of factors affecting phytate hydrolysis in enhancing phytase efficacy in poultry: A review

Directory of Open Access Journals (Sweden)

Noraini*, S.

2017-06-01

Full Text Available Phosphorus in phytate is largely unavailable to chickens unless they are provided with dietary phytase. Phytase was shown to increase phytate degradation in the crop and proventriculus-gizzard and very little phytate degradation occurred in the duodenum-jejunum or ileum. These previous investigations were conducted on chickens fed corn based diet but not with wheat based diet. Increase in digesta passage or mean retention time (MRT along the gastrointestinal tract could enhance phytase efficacy as the prolonged reaction time between substrates and phytase may further facilitate phytate dephosphorylation. Dietary fat and fibre supplementation have been shown to influence intestinal MRT in chickens therefore it is expected that inclusion of both dietary fat and fibre could be manipulated to further improve phytase efficacy in broiler chickens. This paper provides a brief review of in vitro phytate hydrolysis, phytate hydrolysis in the gastrointestinal tract of broilers and factors that affect phytate hydrolysis that can be manipulated to enhance the efficacy of phytase in poultry diets.

Quantitative ultrasound characterization of tumor cell death: ultrasound-stimulated microbubbles for radiation enhancement.

Directory of Open Access Journals (Sweden)

Hyunjung Christina Kim

Full Text Available The aim of this study was to assess the efficacy of quantitative ultrasound imaging in characterizing cancer cell death caused by enhanced radiation treatments. This investigation focused on developing this ultrasound modality as an imaging-based non-invasive method that can be used to monitor therapeutic ultrasound and radiation effects. High-frequency (25 MHz ultrasound was used to image tumor responses caused by ultrasound-stimulated microbubbles in combination with radiation. Human prostate xenografts grown in severe combined immunodeficiency (SCID mice were treated using 8, 80, or 1000 µL/kg of microbubbles stimulated with ultrasound at 250, 570, or 750 kPa, and exposed to 0, 2, or 8 Gy of radiation. Tumors were imaged prior to treatment and 24 hours after treatment. Spectral analysis of images acquired from treated tumors revealed overall increases in ultrasound backscatter intensity and the spectral intercept parameter. The increase in backscatter intensity compared to the control ranged from 1.9±1.6 dB for the clinical imaging dose of microbubbles (8 µL/kg, 250 kPa, 2 Gy to 7.0±4.1 dB for the most extreme treatment condition (1000 µL/kg, 750 kPa, 8 Gy. In parallel, in situ end-labelling (ISEL staining, ceramide, and cyclophilin A staining demonstrated increases in cell death due to DNA fragmentation, ceramide-mediated apoptosis, and release of cyclophilin A as a result of cell membrane permeabilization, respectively. Quantitative ultrasound results indicated changes that paralleled increases in cell death observed from histology analyses supporting its use for non-invasive monitoring of cancer treatment outcomes.

Screening of new substances for radiation protection and technology development of efficacy improvement

Energy Technology Data Exchange (ETDEWEB)

Yoo, Byung Sun; Park, Sun Young; Jang, Eun Jung [Kyonggi University, Suwon (Korea, Republic of)

2005-03-15

To evaluate the radioprotective efficacy of candidate compounds, we examined the effects of selenium compounds, melatonin, and propolis on the colony forming efficiency (CFE) of gamma-irradiated CHO cells. - Protective effects of selenium compounds against radiation-induced cytotoxicity Sodium selenite showed protective effects at low concentrations against radiation-induced toxicity in CHO cells, whereas its effects were weak at higher concentrations. Selenomethionine also reduced the radiation-induced cytotoxicity. Both of these compounds showed highest protective effects at the concentration of 1 uM. - Protective effects of melatonin against radiation-induced cytotoxicity Melatonin showed the protective effects against radiation-induced cytotoxicity, and the protection was highest at 1 mM concentration. - Protective effects of selenium compounds against hydrogen peroxide-induced cytotoxicity Propolis showed dose-dependent inhibition of hydrogen peroxide-induced cytotoxicity. In particular, the highest inhibition was observed when propolis were treated at 0.3 and 1 ng/ml 24h prior to the hydrogen peroxide treatment. The protective effects of propolis was observed only when it was pretreated at least 8 hours before hydrogen peroxide treatment.

Screening of new substances for radiation protection and technology development of efficacy improvement

International Nuclear Information System (INIS)

Yoo, Byung Sun; Park, Sun Young; Jang, Eun Jung

2005-03-01

To evaluate the radioprotective efficacy of candidate compounds, we examined the effects of selenium compounds, melatonin, and propolis on the colony forming efficiency (CFE) of gamma-irradiated CHO cells. - Protective effects of selenium compounds against radiation-induced cytotoxicity Sodium selenite showed protective effects at low concentrations against radiation-induced toxicity in CHO cells, whereas its effects were weak at higher concentrations. Selenomethionine also reduced the radiation-induced cytotoxicity. Both of these compounds showed highest protective effects at the concentration of 1 uM. - Protective effects of melatonin against radiation-induced cytotoxicity Melatonin showed the protective effects against radiation-induced cytotoxicity, and the protection was highest at 1 mM concentration. - Protective effects of selenium compounds against hydrogen peroxide-induced cytotoxicity Propolis showed dose-dependent inhibition of hydrogen peroxide-induced cytotoxicity. In particular, the highest inhibition was observed when propolis were treated at 0.3 and 1 ng/ml 24h prior to the hydrogen peroxide treatment. The protective effects of propolis was observed only when it was pretreated at least 8 hours before hydrogen peroxide treatment

Arsenic trioxide synergistically enhances radiation response in human cervical cancer cells through ROS-dependent p38 MAPK and JNK signalling pathway

Energy Technology Data Exchange (ETDEWEB)

Kang, Young-Hee; Park, Seung-Moo; Kim, Min-Jeong [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)] (and others)

2006-07-01

Many factors affect susceptibility of tumor cells to ionizing radiation. Among them intrinsic apoptosis sensitivity or resistancy seems to play an important role. The use of chemical modifiers as radiosensitizers in combination with low-dose irradiation may increase the therapeutic efficacy by overcoming a high apoptotic threshold. Several recent studies demonstrated additive effects of As{sub 2}O{sub 3} with conventional chemotherapeutic agents such as cisplatin, adriamycin, and etoposide, but no synergism. Previously, we have shown for the first time that As{sub 2}O{sub 3} sensitize human cervical cancer cells to ionizing radiation. Treatment of As{sub 2}O{sub 3} in combination of ionizing radiation has synergistic effects in decreasing clonogenic survival and in the regression of tumor growth in xenografts. We also have shown that the combination treatment enhanced apoptotic cell death through a reactive oxygen species-dependent pathway in human cervical cancer cells. In this study, we investigated the regulatory mechanism of ROS-mediated mitochondrial apoptotic cell death induced by combination treatment with As{sub 2}O{sub 3} and ionizing radiation in human cervical cancer cells.

Coherently enhanced radiation reaction effects in laser-vacuum acceleration of electron bunches

NARCIS (Netherlands)

Smorenburg, P.W.; Kamp, L.P.J.; Geloni, G.; Luiten, O.J.

2010-01-01

The effects of coherently enhanced radiation reaction on the motion of subwavelength electron bunches in interaction with intense laser pulses are analyzed. The radiation reaction force behaves as a radiation pressure in the laser beam direction, combined with a viscous force in the perpendicular

Effects of enhanced ultraviolet radiation-B on maize in arid regions of middle-high elevation

International Nuclear Information System (INIS)

Zhang Lei; Wang Lianxi; Li Fusheng

2009-01-01

[Objective]The experiment aimed to explore the influence of enhanced ultraviolet radiation-B on maize in arid regions of middle-high elevation for correct assessing the influence of enhanced ultraviolet radiation-B on maize and providing scientific reference to make proper countermeasures.[Method] The location test in field and lift lamp of UV-B were used to observe the changes of maize height , leaf area and number of green leaves under influences of different UV-B radiation. [Result]In arid regions of middle-high elevation, enhanced ultraviolet radiation-B could dwarf maize plant, decrease leaf area, decline number of green leaves and yield. The reason of decreasing leaf area was that enhanced ultraviolet radiation-B shortened leaf length and leaf width while the reason of declining yield was that yield components were all negatively influenced and with the increase of ultraviolet radiation-B, the yield declined dramatically.[Conclusion]The result of this experiment would be good for maize production in arid regions of middle-high elevation

The Development of a Cultural-Based Educational Program to Enhance Breast Self-Examination (BSE Self-Efficacy

Directory of Open Access Journals (Sweden)

Juanita Juanita

2012-08-01

Full Text Available Purpose: To develop the educational program which is appropriate with Islamic culture in order to enhance BSE self-efficacy of nursing students and thus promote BSE practice. Method: This study is a development research study which is consisting of three phases including: 1 reviewing several existing BSE educational programs; 2 program design based on SCT and Islamic culture; and 3 program validation by three experts. Result: Based on previous studies, the most appropriate theory to enhance self-efficacy was Social Cognitive Theory (SCT because this theory provides several strategies to increase the self-efficacy. Further, the program that used Islamic culture was more appropriate to increase BSE practice among Muslim women. As a result, the newly developed program was developed used SCT and Islamic culture. This program was comprised of four sessions including: 1 exploring Islamic mandate on prevention and individual responsibility in health promotion, and culture-related beliefs toward BSE, 2 health education by conducting lecturing session and watching a video about BSE procedures, 3 BSE training activities including BSE demonstration and return demonstration, 4 follow-up by conducting a meeting. Conclusion: The cultural-based educational program for enhancing BSE self-efficacy and promoting BSE is a program using multifaceted methods. It designed based on a review of the literature from previous studies and were supported by research findings on experimental studies in other population. Keywords: Cultural, Educational program development, Breast self-examination, Self-efficacy.

Gold Nanoparticles and Their Alternatives for Radiation Therapy Enhancement

Directory of Open Access Journals (Sweden)

Daniel R. Cooper

2014-10-01

Full Text Available Radiation therapy is one of the most commonly used treatments for cancer. The dose of delivered ionizing radiation can be amplified by the presence of high-Z materials via an enhancement of the photoelectric effect; the most widely studied material is gold (atomic number 79. However, a large amount is needed to obtain a significant dose enhancement, presenting a challenge for delivery. In order to make this technique of broader applicability, the gold must be targeted, or alternative formulations developed that do not rely solely on the photoelectric effect. One possible approach is to excite scintillating nanoparticles with ionizing radiation, and then exploit energy transfer between these particles and attached dyes in a manner analogous to photodynamic therapy. Doped rare-earth halides and semiconductor quantum dots have been investigated for this purpose. However, although the spectrum of emitted light after radiation excitation is usually similar to that seen with light excitation, the yield is not. Measurement of scintillation yields is challenging, and in many cases has been done only for bulk materials, with little understanding of how the principles translate to the nanoscale. Another alternative is to use local heating using gold or iron, followed by application of ionizing radiation. Hyperthermia pre-sensitizes the tumors, leading to an improved response. Another approach is to use chemotherapeutic drugs that can radiosensitize tumors. Drugs may be attached to high-Z nanoparticles or encapsulated. This article discusses each of these techniques, giving an overview of the current state of nanoparticle-assisted radiation therapy and future directions.

Enhancing Teacher Efficacy and Pedagogical Practices amongst General and Special Education Teachers

Science.gov (United States)

Coleman, Michael

2017-01-01

The purpose of this action research project was to collect both qualitative and quantitative data to acquire information in teacher efficacy from the viewpoint of teachers themselves so that pedagogical practices could be enhanced to better serve the special needs student population. In this study, the relationship between teachers' perception of…

Efficacy of various schemes of therapy of patients with radiation limb edema

International Nuclear Information System (INIS)

Kuz'mina, E.G.; Degtyareva, A.A.; Zubova, N.D.; Guseva, L.I.; Klimanov, M.E.

1987-01-01

The efficacy of various therapeutic schemes: medicinal (basic therapy - BT), acupuncture (AP) and laser therapy (LT) against a background of basic therapy - was assessed and compared in 36 patients with radiation limb edema. It was established that a degree of a decrease in edemas, the improvement of indices of rheovasography grew in the following order: BT → AP → LT. The recovery of the lymph flow and immunological indices were the same in all therapeutic schemes

Gamma radiation induced enhancement in the antioxidant and radioprotective activities of flavonoids

International Nuclear Information System (INIS)

Arul Anantha Kumar, A.; Sonwani, Swetha; Bakkiam, D.

2018-01-01

Recently γ-radiation has been used as a tool to induce structural changes in natural biomolecules to enhance their biological and physiological properties. Flavonoids are a family of plant derived polyphenolic compounds having considerable scientific and therapeutic importance. Structurally they are the benzo-γ-pyrone derivatives containing phenolic and pyrane rings. Flavonoid radioprotection is an intense area of research thanks to features like natural origin, effectiveness at non-toxic dose levels and lack of side effects. But till date no report is available on the effect of γ-radiation mediated enhancement in radioprotection activity of flavonoids. In view of this the present study was carried out to determine the γ-radiation induced structural changes in selected flavonoids i.e. apigenin, naringenin and genistein and also to explore the possibility of enhancement in their antioxidant and radioprotective activities

Biotechnological Approaches to Enhance Halotolerance and Photosynthetic Efficacy in the Cyanobacterium, Fremyella diplosiphon

Science.gov (United States)

Tabatabai, Ben

Growing concerns over dwindling energy supplies linked to nonrenewable fossil fuels have driven profound interest in biofuels as a clean and sustainable alternative. Cyanobacteria are a promising source of third-generation biofuel due to their fast generation time and high net biomass conversion. In this study, the effect of salinity stress on Fremyella diplosiphon, a model organism for studying photosynthetic pathways, was investigated and nanobiotechnological approaches undertaken to enhance its halotolerance and photosynthetic efficacy. Heat-induced mutagenesis resulted in a mutant strain that could survive in 20 g L-1 sodium chloride (NaCl) with no loss in pigmentation. To further enhance F. diplosiphon halotolerance, expression plasmids harboring the hlyB and mdh genes were overexpressed in the wild type resulting in two transformants that thrived in 35 g L-1 NaCl, the average salinity of sea water. In addition, no significant reduction in photosynthetic efficacy was detected in the halotolerant strains relative to the wild type. Total lipid content and fatty acid methyl ester composition of wild type and halotolerant strains were assessed for their potential as a production-scale biofuel agent. Methyl palmitate, the methyl ester of hexodeconoate (C16:0), was found to be most abundant in the wild type and transformants accounting for 60-70% of total FAMEs produced. Efforts to enhance the photosynthetic efficiency of the strains revealed that gold nanoparticle-derived surface plasmon resonance augmented culture growth and pigment accumulation. Cell-nanoparticles interactions were visualized using scanning and transmission electron microscopy. Our findings address two key challenges that cyanobacterial biofuel agents need to overcome: enhanced halotolerance and photosynthetic efficacy to minimize freshwater input and artificial light supply. These innovations have paved the way for an efficient cyanobacterial cultivation system for large-scale production of

Enhanced radiative Auger emission from lithiumlike 20Ca17+

International Nuclear Information System (INIS)

Bernstein, E.M.; Clark, M.W.; Tanis, J.A.; Graham, W.G.; Morgan, T.J.; Stoeckli, M.P.; Berkner, K.H.; Schlachter, A.S.; Stearns, J.W.

1991-01-01

Radiative Auger emission (RAE) from lithiumlike 20 Ca 17+ projectiles excited in collisions with He has been measured. The intensity of RAE photons relative to K α X-ray emission is enhanced by a factor of 10-17 compared with theoretical calculations for ions with few electron vacancies. The enhancement of RAE for Ca 17+ is consistent with the results reported previously for lithiumlike 16 S 13+ and 23 V 20+ and indicates a systematic dependence on Z. Both the enhancement and the relative RAE transition rate increase with Z. (orig.)

Bulk Nanostructured FCC Steels With Enhanced Radiation Tolerance

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xinghang; Hartwig, K. Ted; Allen, Todd; Yang, Yong

2012-10-27

The objective of this project is to increase radiation tolerance in austenitic steels through optimization of grain size and grain boundary (GB) characteristics. The focus will be on nanocrystalline austenitic Fe-Cr-Ni alloys with an fcc crystal structure. The long-term goal is to design and develop bulk nanostructured austenitic steels with enhanced void swelling resistance and substantial ductility, and to enhance their creep resistance at elevated temperatures via GB engineering. The combination of grain refinement and grain boundary engineering approaches allows us to tailor the material strength, ductility, and resistance to swelling by 1) changing the sink strength for point defects, 2) by increasing the nucleation barriers for bubble formation at GBs, and 3) by changing the precipitate distributions at boundaries. Compared to ferritic/martensitic steels, austenitic stainless steels (SS) possess good creep and fatigue resistance at elevated temperatures, and better toughness at low temperature. However, a major disadvantage of austenitic SS is that they are vulnerable to significant void swelling in nuclear reactors, especially at the temperatures and doses anticipated in the Advanced Burner Reactor. The lack of resistance to void swelling in austenitic alloys led to the switch to ferritic/martensitic steels as the preferred material for the fast reactor cladding application. Recently a type of austenitic stainless steel, HT-UPS, was developed at ORNL, and is expected to show enhanced void swelling resistance through the trapping of point defects at nanometersized carbides. Reducing the grain size and increasing the fraction of low energy grain boundaries should reduce the available radiation-produced point defects (due to the increased sink area of the grain boundaries), should make bubble nucleation at the boundaries less likely (by reducing the fraction of high-energy boundaries), and improve the strength and ductility under radiation by producing a higher

Macrophage biology plays a central role during ionizing radiation-elicited tumor response

Directory of Open Access Journals (Sweden)

Qiuji Wu

2017-08-01

Full Text Available Radiation therapy is one of the major therapeutic modalities for most solid tumors. The anti-tumor effect of radiation therapy consists of the direct tumor cell killing, as well as the modulation of tumor microenvironment and the activation of immune response against tumors. Radiation therapy has been shown to promote immunogenic cells death, activate dendritic cells and enhance tumor antigen presentation and anti-tumor T cell activation. Radiation therapy also programs innate immune cells such as macrophages that leads to either radiosensitization or radioresistance, according to different tumors and different radiation regimen studied. The mechanisms underlying radiation-induced macrophage activation remain largely elusive. Various molecular players such as NF-κB, MAPKs, p53, reactive oxygen species, inflammasomes have been involved in these processes. The skewing to a pro-inflammatory phenotype thus results in the activation of anti-tumor immune response and enhanced radiotherapy effect. Therefore, a comprehensive understanding of the mechanism of radiation-induced macrophage activation and its role in tumor response to radiation therapy is crucial for the development of new therapeutic strategies to enhance radiation therapy efficacy.

Exposition of the operator's eye lens and efficacy of radiation shielding in fluoroscopically guided interventions

International Nuclear Information System (INIS)

Galster, M.; Adamus, R.; Guhl, C.; Uder, M.

2013-01-01

Purpose: Efficacy of radiation protection tools for the eye lens dose of the radiologist in fluoroscopic interventions. Materials and Methods: A patient phantom was exposed using a fluoroscopic system. Dose measurements were made at the eye location of the radiologist using an ionization chamber. The setting followed typical fluoroscopic interventions. The reduction of scattered radiation by the equipment-mounted shielding (undercouch drapes and overcouch top) was evaluated. The ceiling-suspended lead acrylic glass screen was tested in scattered radiation generated by a slab phantom. The protective properties of different lead glass goggles and lead acrylic visors were evaluated by thermoluminescence measurements on a head phantom in the primary beam. Results: The exposition of the lens of about 110 to 550 μSv during radiologic interventions is only slightly reduced by the undercouch drapes. Applying the top in addition to the drapes reduces the lens dose by a factor of 2 for PA projections. In 25 LAO the dose is reduced by a factor between 1.2 and 5. The highest doses were measured for AP angulations furthermore the efficacy of the equipment-mounted shielding is minimal. The ceiling-suspended lead screen reduced scatter by a factor of about 30. The lead glass goggles and visors reduced the lens dose up to a factor of 8 to 10. Depending on the specific design, the tested models are less effective especially for radiation from lateral with cranial angulation of the beam. Occasionally the visors even caused an increase of dose. Conclusion: The exposition of the eye lens can be kept below the new occupational limit recommended by the ICRP if the radiation shielding equipment is used consistently. (orig.)

Genetic modification to induce CXCR2 overexpression in mesenchymal stem cells enhances treatment benefits in radiation-induced oral mucositis.

Science.gov (United States)

Shen, Zongshan; Wang, Jiancheng; Huang, Qiting; Shi, Yue; Wei, Zhewei; Zhang, Xiaoran; Qiu, Yuan; Zhang, Min; Wang, Yi; Qin, Wei; Huang, Shuheng; Huang, Yinong; Liu, Xin; Xia, Kai; Zhang, Xinchun; Lin, Zhengmei

2018-02-14

Radiation-induced oral mucositis affects patient quality of life and reduces tolerance to cancer therapy. Unfortunately, traditional treatments are insufficient for the treatment of mucositis and might elicit severe side effects. Due to their immunomodulatory and anti-inflammatory properties, the transplantation of mesenchymal stem cells (MSCs) is a potential therapeutic strategy for mucositis. However, systemically infused MSCs rarely reach inflamed sites, impacting their clinical efficacy. Previous studies have demonstrated that chemokine axes play an important role in MSC targeting. By systematically evaluating the expression patterns of chemokines in radiation/chemical-induced oral mucositis, we found that CXCL2 was highly expressed, whereas cultured MSCs negligibly express the CXCL2 receptor CXCR2. Thus, we explored the potential therapeutic benefits of the transplantation of CXCR 2 -overexpressing MSCs (MSCs CXCR2 ) for mucositis treatment. Indeed, MSCs CXCR2 exhibited enhanced targeting ability to the inflamed mucosa in radiation/chemical-induced oral mucositis mouse models. Furthermore, we found that MSC CXCR2 transplantation accelerated ulcer healing by suppressing the production of pro-inflammatory chemokines and radiogenic reactive oxygen species (ROS). Altogether, these findings indicate that CXCR2 overexpression in MSCs accelerates ulcer healing, providing new insights into cell-based therapy for radiation/chemical-induced oral mucositis.

Estramustine: A novel radiation enhancer in human carcinoma cells

International Nuclear Information System (INIS)

Ryu, S.; Gabel, M.; Khil, M.S.

1994-01-01

Estramustine (EM), an antimicrotubule agent, binds microtubule-associated proteins, causes spindle disassembly, and arrests cells at the late G 2 /M phase of the cell cycle. Since cells in the G 2 /M phase are the most radiosensitive and some human cancer cells contain high level of EM-binding protein, experiments were carried out to determine whether radiation sensitization could be obtained in human carcinoma cells. Cells containing a high level of EM-binding protein such as prostate carcinoma (DU-145), breast carcinoma (MCF-7), and malignant glioma (U-251) were used to demonstrate radiosensitization. Cervical carcinoma (HeLa-S 3 ) and colon carcinoma (HT-29) cells which are not known to contain EM-binding protein were also employed. Cell survival was assayed by the colony forming ability of single plated cells in culture to obtain dose-survival curves. Pretreatment of DU-145, MCF-7, and U-251 cells to a nontoxic concentration (5 μM) of EM for more than one cell cycle time, substantially enhanced the radiation-induced cytotoxicity. The sensitizer enhancement ratio of these cells ranged from 1.35-1.52. The magnitude of the enhancement was dependent on the drug concentration and exposure time. The rate of cell accumulation in G 2 /M phase, as determined by flow cytometry, increased with longer treatment time in the cell lines which showed radiosensitization. Other antimicrotubule agents such as taxol and vinblastine caused minimal or no radiosensitization at nontoxic concentrations. The data provide a radiobiological basis for using EM as a novel radiation enhancer, with the property of tissue selectivity. 29 refs., 4 figs., 1 tab

Radiation dose of aircrews during a solar proton event without ground-level enhancement

Directory of Open Access Journals (Sweden)

R. Kataoka

2015-01-01

Full Text Available A significant enhancement of radiation doses is expected for aircrews during ground-level enhancement (GLE events, while the possible radiation hazard remains an open question during non-GLE solar energetic particle (SEP events. Using a new air-shower simulation driven by the proton flux data obtained from GOES satellites, we show the possibility of significant enhancement of the effective dose rate of up to 4.5 μSv h−1 at a conventional flight altitude of 12 km during the largest SEP event that did not cause a GLE. As a result, a new GOES-driven model is proposed to give an estimate of the contribution from the isotropic component of the radiation dose in the stratosphere during non-GLE SEP events.

Radiation-enhanced self- and boron diffusion in germanium

DEFF Research Database (Denmark)

Schneider, S.; Bracht, H.; Klug, J.N.

2013-01-01

We report experiments on proton radiation-enhanced self- and boron (B) diffusion in germanium (Ge) for temperatures between 515 ∘ C and 720 ∘ C. Modeling of the experimental diffusion profiles measured by means of secondary ion mass spectrometry is achieved on the basis of the Frenkel pair reaction...

Praziquantel synergistically enhances paclitaxel efficacy to inhibit cancer cell growth.

Directory of Open Access Journals (Sweden)

Zhen Hua Wu

Full Text Available The major challenges we are facing in cancer therapy with paclitaxel (PTX are the drug resistance and severe side effects. Massive efforts have been made to overcome these clinical challenges by combining PTX with other drugs. In this study, we reported the first preclinical data that praziquantel (PZQ, an anti-parasite agent, could greatly enhance the anticancer efficacy of PTX in various cancer cell lines, including PTX-resistant cell lines. Based on the combination index value, we demonstrated that PZQ synergistically enhanced PTX-induced cell growth inhibition. The co-treatment of PZQ and PTX also induced significant mitotic arrest and activated the apoptotic cascade. Moreover, PZQ combined with PTX resulted in a more pronounced inhibition of tumor growth compared with either drug alone in a mouse xenograft model. We tried to investigate the possible mechanisms of this synergistic efficacy induced by PZQ and PTX, and we found that the co-treatment of the two drugs could markedly decrease expression of X-linked inhibitor of apoptosis protein (XIAP, an anti-apoptotic protein. Our data further demonstrated that down-regulation of XIAP was required for the synergistic interaction between PZQ and PTX. Together, this study suggested that the combination of PZQ and PTX may represent a novel and effective anticancer strategy for optimizing PTX therapy.

Heat transfer enhancement of car radiator using aqua based magnesium oxide nanofluids

OpenAIRE

Ali Hafiz Muhammad; Azhar Muhammad Danish; Saleem Musab; Saeed Qazi Samie; Saieed Ahmed

2015-01-01

The focus of this research paper is on the application of water based MgO nanofluids for thermal management of a car radiator. Nanofluids of different volumetric concentrations (i.e. 0.06%, 0.09% and 0.12%) were prepared and then experimentally tested for their heat transfer performance in a car radiator. All concentrations showed enhancement in heat transfer compared to the pure base fluid. A peak heat transfer enhancement of 31% was obtained at 0.12 % vol...

Hydroxycinnamic acid derivatives in an aquatic liverwort as possible bioindicators of enhanced UV radiation

Energy Technology Data Exchange (ETDEWEB)

Arroniz-Crespo, M.; Nunez-Olivera, E. [Universidad de La Rioja, Complejo Cientifico-Tecnologico, Avda. Madre de Dios 51, 26006 Logrono (La Rioja) (Spain); Martinez-Abaigar, J. [Universidad de La Rioja, Complejo Cientifico-Tecnologico, Avda. Madre de Dios 51, 26006 Logrono (La Rioja) (Spain)], E-mail: javier.martinez@unirioja.es

2008-01-15

We examined, under laboratory conditions, the physiological responses of the aquatic liverwort Jungermannia exsertifolia subsp. cordifolia to artificially enhanced ultraviolet (UV) radiation for 82 days, especially considering the responses of five hydroxycinnamic acid derivatives. This species lives in mountain streams, where it is exposed to low temperatures and high UV levels, and this combination is believed to increase the adverse effects of UV. Enhanced UV radiation hardly caused any change in several physiological variables indicative of vitality, such as F{sub v}/F{sub m} and chlorophylls/phaeopigments ratio (OD430/OD410). Thus, this liverwort seemed to be tolerant to UV radiation, probably due to the accumulation of three UV-absorbing hydroxycinnamic acid derivatives: p-coumaroylmalic acid, 5''-(7'',8''-dihydroxycoumaroyl)-2-caffeoylmalic acid, and 5''-(7'',8''-dihydroxy-7-O-{beta}-glucosyl-coumaroyl)-2-caffeoylmalic acid. These compounds might serve as bioindicators of enhanced UV radiation. - Several hydroxycinnamic acid derivatives of an aquatic liverwort are induced by enhanced UV radiation and might serve as bioindicators of changes in UV levels.

Long-term efficacy of a mini-course in radiation-reducing techniques in invasive cardiology

International Nuclear Information System (INIS)

Kuon, E.; Empen, K.; Hummel, A.; Doerr, M.; Reffelmann, T.; Felix, S.B.; Weitmann, K.; Hoffmann, W.; Staudt, A.

2013-01-01

Purpose: To validate the long-term efficacy of a 90-min. educational mini-course in less-irradiating cardiac interventional techniques. Materials and Methods: Before, two months after, and two years after the mini-course (periods I, II, and III), we analyzed the following radiation dose parameters for ten coronary angiographies (CA), performed by each of 7 cardiologists: total dose-area product (DAP), radiographic and fluoroscopic DAP fractions, number of radiographic frames and runs, and fluoroscopy time. Results: The median patient DAP for periods I, II and III was 31.4, 15.8 and 8.5 Gy x cm 2 , respectively. The long-term effect was related to shorter median fluoroscopy times (180, 172, and 120 s), shorter (57, 52, and 45) and fewer (12, 12, and 10) radiographic runs, consistent collimation and restriction to an adequate image quality. Both radiographic DAP/frame (28.7, 17.0, and 18.4 mGy x cm 2 ) and fluoroscopic DAP/second (45.7, 24.2, and 10.0 mGy x cm 2 ) decreased significantly. The multivariate linear regression analysis confirmed the increasing efficacy of the mini-course itself (-44.6 and -60.7 %), and revealed a decreasing influence of the interventionalist's experience (-8.6 % and -4.9 % per 1,000 CAs, lifelong performed until the mini-course). The number of CAs performed after the mini-course did not influence the long-term DAP results. Conclusion: The presented educational mini-course allows a significant, long-lasting, and apparently ongoing reduction of patient radiation exposure due to CA. A self-surveillant documentation of relevant radiation parameters is well suited to monitor and improve each operator's individual long-term radiation-reducing efforts. (orig.)

Nonrelativistic electron bunch train for coherently enhanced terahertz radiation sources

International Nuclear Information System (INIS)

Li Yuelin; Kim, Kwang-Je

2008-01-01

We propose to generate a train of prebunched electron beams for producing coherently enhanced Smith-Purcell radiation [S. J. Smith and E. M. Purcell, Phys. Rev. 92, 1069 (1953)] in the terahertz wavelength range. In this scheme, a train of picosecond laser pulses is produced to drive a photoemission gun to generate a train of 50 keV electron pulses. The parameters are chosen so that the space-charge effect does not destroy the pulse time structure. Smith-Purcell radiation from the electron pulse train is enhanced due both to the short length of the individual electron bunch and to the repetitive structure of the beam. Example systems producing coherent terahertz power at about 1 mW are described

Radiosensitization: enhancing the radiation inactivation of foodborne bacteria

Science.gov (United States)

Borsa, J.; Lacroix, M.; Ouattara, B.; Chiasson, F.

2004-09-01

Irradiation of meat products to kill pathogens can be limited by radiation-induced detriment of sensory quality. Since such detriment is directly related to dose, one approach to reduce it is by devising means to lower the dose of radiation required for processing. Increasing the radiation sensitivity of the target microorganisms would lower the dose required for a given level of microbial kill. In this work, the radiation sensitivities of inoculated Escherichia coli and Salmonella typhi in ground beef were examined under a variety of conditions. Results showed that specific manipulations of treatment conditions significantly increased the radiation sensitivity of the test organisms, ranging from a few percent to several-fold reduction in D10. In particular, radiation sensitization could be effected by certain additives, including carvacrol, thymol and trans-cinnamaldehyde, and also by certain compositions of modified atmosphere in the package headspace. A combination of additives and modified atmosphere effected a greater radiosensitization effect than could be achieved by either factor applied alone. Radiosensitization could be demonstrated with irradiation of either fresh or frozen ground meat. The radiosensitization phenomenon may be of practical utility in enhancing the technical effectiveness and feasibility of irradiation of a variety of meat and other food products.

Radiosensitization: enhancing the radiation inactivation of foodborne bacteria

Energy Technology Data Exchange (ETDEWEB)

Borsa, J. E-mail: jborsa@mds.nordion.com; Lacroix, M.; Ouattara, B.; Chiasson, F

2004-10-01

Irradiation of meat products to kill pathogens can be limited by radiation-induced detriment of sensory quality. Since such detriment is directly related to dose, one approach to reduce it is by devising means to lower the dose of radiation required for processing. Increasing the radiation sensitivity of the target microorganisms would lower the dose required for a given level of microbial kill. In this work, the radiation sensitivities of inoculated Escherichia coli and Salmonella typhi in ground beef were examined under a variety of conditions. Results showed that specific manipulations of treatment conditions significantly increased the radiation sensitivity of the test organisms, ranging from a few percent to several-fold reduction in D{sub 10}. In particular, radiation sensitization could be effected by certain additives, including carvacrol, thymol and trans-cinnamaldehyde, and also by certain compositions of modified atmosphere in the package headspace. A combination of additives and modified atmosphere effected a greater radiosensitization effect than could be achieved by either factor applied alone. Radiosensitization could be demonstrated with irradiation of either fresh or frozen ground meat. The radiosensitization phenomenon may be of practical utility in enhancing the technical effectiveness and feasibility of irradiation of a variety of meat and other food products.

A new dimension in improved radiation protection by enhanced DNA repair

International Nuclear Information System (INIS)

Riklis, E.

1997-01-01

Radioprotection and photo protection were dependent until now on measures to reduce the amount of damage formed by ionizing and ultraviolet radiations. In both cases the measures are not completely satisfactory: the classical radioprotectors are toxic arid exert serious side effects, and afford a protection factor not higher than around 2. The sunscreens filters are effective for certain wavelength ranges only, and not enough is known about the possible effects of the filters when they absorb light and turn into other chemical entities. Both approaches do not give an answer to damages which are formed in spite of the partial reduction of damage. A new approach offered here is dealing with the damage on a cellular / molecular level, by enhancing the activity of the natural repair enzymes whose task is to remove radiation and photoproducts, rejoin DNA strand breaks and repair the DNA. A combination of vitamins and antioxidants is fulfilling these tasks and provides protection from both ionizing and ultraviolet radiations by enhancing several folds the repair of DNA in living cells. Such a combination which contains the repair enhancers niacinamide and nordihydroguaiaretic acid is employed in preparations named EDNAR ( Enhanced DNA Repair, Patent pending) which demonstrate excellent results of enhancing DNA repair as measured by repair synthesis, and protecting the skin from sunburns as well as skin burns following radiotherapy. These lotions and creams, when not containing any chemical filters yet demonstrating a protective effect, may be called 'the sunscreens without sunscreens'. (author)

Zoledronic acid enhances antitumor efficacy of liposomal doxorubicin.

Science.gov (United States)

Hattori, Yoshiyuki; Shibuya, Kazuhiko; Kojima, Kaori; Miatmoko, Andang; Kawano, Kumi; Ozaki, Kei-Ichi; Yonemochi, Etsuo

2015-07-01

Previously, we found that the injection of zoledronic acid (ZOL) into mice bearing tumor induced changes of the vascular structure in the tumor. In this study, we examined whether ZOL treatment could decrease interstitial fluid pressure (IFP) via change of tumor vasculature, and enhance the antitumor efficacy of liposomal doxorubicin (Doxil®). When ZOL solution was injected at 40 µg/mouse per day for three consecutive days into mice bearing murine Lewis lung carcinoma LLC tumor, depletion of macrophages in tumor tissue and decreased density of tumor vasculature were observed. Furthermore, ZOL treatments induced inflammatory cytokines such as interleukin (IL)-10 and -12, granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF)-α in serum of LLC tumor-bearing mice, but not in normal mice, indicating that ZOL treatments might induce an inflammatory response in tumor tissue. Furthermore, ZOL treatments increased antitumor activity by Doxil in mice bearing a subcutaneous LLC tumor, although they did not significantly increase the tumor accumulation of doxorubicin (DXR). These results suggest that ZOL treatments might increase the therapeutic efficacy of Doxil via improvement of DXR distribution in a tumor by changing the tumor vasculature. ZOL treatment can be an alternative approach to increase the antitumor effect of liposomal drugs.

[Exposition of the operator's eye lens and efficacy of radiation shielding in fluoroscopically guided interventions].

Science.gov (United States)

Galster, M; Guhl, C; Uder, M; Adamus, R

2013-05-01

Efficacy of radiation protection tools for the eye lens dose of the radiologist in fluoroscopic interventions. A patient phantom was exposed using a fluoroscopic system. Dose measurements were made at the eye location of the radiologist using an ionization chamber. The setting followed typical fluoroscopic interventions. The reduction of scattered radiation by the equipment-mounted shielding (undercouch drapes and overcouch top) was evaluated. The ceiling-suspended lead acrylic glass screen was tested in scattered radiation generated by a slab phantom. The protective properties of different lead glass goggles and lead acrylic visors were evaluated by thermoluminescence measurements on a head phantom in the primary beam. The exposition of the lens of about 110 to 550 μSv during radiologic interventions is only slightly reduced by the undercouch drapes. Applying the top in addition to the drapes reduces the lens dose by a factor of 2 for PA projections. In 25°LAO the dose is reduced by a factor between 1.2 and 5. The highest doses were measured for AP angulations furthermore the efficacy of the equipment-mounted shielding is minimal. The ceiling-suspended lead screen reduced scatter by a factor of about 30. The lead glass goggles and visors reduced the lens dose up to a factor of 8 to 10. Depending on the specific design, the tested models are less effective especially for radiation from lateral with cranial angulation of the beam. Occasionally the visors even caused an increase of dose. The exposition of the eye lens can be kept below the new occupational limit recommended by the ICRP if the radiation shielding equipment is used consistently. © Georg Thieme Verlag KG Stuttgart · New York.

Terahertz-Radiation-Enhanced Emission of Fluorescence from Gas Plasma

International Nuclear Information System (INIS)

Liu Jingle; Zhang, X.-C.

2009-01-01

We report the study of femtosecond laser-induced air plasma fluorescence under the illumination of terahertz (THz) pulses. Semiclassical modeling and experimental verification indicate that time-resolved THz radiation-enhanced emission of fluorescence is dominated by the electron kinetics and the electron-impact excitation of gas molecules or ions. We demonstrate that the temporal waveform of the THz field could be retrieved from the transient enhanced fluorescence, making omnidirectional, coherent detection available for THz time-domain spectroscopy.

Spin Lattice Relaxation EPR pO2 Images May Direct the Location of Radiation Tumor Boosts to Enhance Tumor Cure.

Science.gov (United States)

Epel, Boris; Krzykawska-Serda, Martyna; Tormyshev, Victor; Maggio, Matthew C; Barth, Eugene D; Pelizzari, Charles A; Halpern, Howard J

2017-12-01

Radiation treatment success and high tumor oxygenation and success have been known to be highly correlated. This suggests that radiation therapy guided by images of tumor regions with low oxygenation, oxygen-guided radiation therapy (OGRT) may be a promising enhancement of cancer radiation treatment. Before applying the technique to human subjects, OGRT needs to be tested in animals, most easily in rodents. Electron paramagnetic resonance imaging provides quantitative maps of tissue and tumor oxygen in rodents with 1 mm spatial resolution and 1 torr pO 2 resolution at low oxygen levels. The difficulty of using mouse models is their small size and that of their tumors. To overcome this we used XRAD225Cx micro-CT/ therapy system and 3D printed conformal blocks. Radiation is delivered first to a uniform 15% tumor control dose for the whole tumor and then a boost dose to either hypoxic tumor regions or equal volumes of well oxygenated tumor. Delivery of the booster dose used a multiple beam angles to deliver radiation beams whose shape conforms to that of all hypoxic regions or fully avoids those regions. To treat/avoid all hypoxic regions we used individual radiation blocks 3D-printed from acrylonitrile butadiene styrene polymer infused with tungsten particles fabricated immediately after imaging to determine regions with pO 2 less than 10 torr. Preliminary results demonstrate the efficacy of the radiation treatment with hypoxic boosts with syngeneic FSa fibrosarcoma tumors in the legs of C3H mice.

Inspiring Instructional Change in Elementary School Science: The Relationship Between Enhanced Self-efficacy and Teacher Practices

Science.gov (United States)

Sandholtz, Judith Haymore; Ringstaff, Cathy

2014-10-01

This longitudinal study examined the extent to which teachers' participation in a 3-year professional development program enhanced their self-efficacy and prompted changes in science instruction in the early elementary grades. The study used a mixed-methods design, and included 39 teachers who taught in kindergarten, first grade, or second grade classrooms in rural school districts. Data sources, administered pre-program and at the end of each year, included a self-efficacy assessment and teacher survey. Interviews and classroom observations provided corroborating data about teachers' beliefs and science instruction. Results showed significant increases in teachers' overall self-efficacy in teaching science, personal efficacy, and outcome expectancy efficacy during the 3 years. Gains in self-efficacy were correlated with changes in reported instructional practices, particularly student participation activities. However, changes in self-efficacy tended not to be correlated with changes in instructional time. Contextual factors beyond teachers' direct control, such as curricular and testing requirements in mathematics and language arts influenced time allotted to science instruction.

Ionizing and ultraviolet radiation enhances the efficiency of DNA mediated gene transfer in vitro

International Nuclear Information System (INIS)

Perez, C.F.

1984-08-01

The enhancement effects of ionizing and non-ionizing radiation on the efficiency of DNA mediated gene transfer were studied. Confluent Rat-2 cells were transfected with purified SV40 viral DNA, irradiated with either X-rays or ultraviolet, trypsinized, plated, and assayed for the formation of foci on Rat-2 monolayers. Both ionizing and ultraviolet radiation enhanced the frequency of A-gene transformants/survivor compared to unirradiated transfected cells. These enhancements were non-linear and dose dependent. A recombinant plasmid, pOT-TK5, was constructed that contained the SV40 virus A-gene and the Herpes Simplex virus (HSV) thymidine kinase (TK) gene. Confluent Rat-2 cells transfected with pOT-TK5 DNA and then immediately irradiated with either X-rays or 330 MeV/amu argon particles at the Berkeley Bevalac showed a higher frequency of HAT + colonies/survivor than unirradiated transfected cells. Rat-2 cells transfected with the plasmid, pTK2, containing only the HSV TK-gene were enhanced for TK-transformation by both X-rays and ultraviolet radiation. The results demonstrate that radiation enhancement of the efficiency of DNA mediated gene transfer is not explained by increased nuclear uptake of the transfected DNA. Radiation increases the competence of the transfected cell population for genetic transformation. Three models for this increased competence are presented. The targeted integration model, the inducible recombination model, the partition model, and the utilization of DNA mediated gene transfer for DNA repair studies are discussed. 465 references

Ionizing and ultraviolet radiation enhances the efficiency of DNA mediated gene transfer in vitro

Energy Technology Data Exchange (ETDEWEB)

Perez, C.F.

1984-08-01

The enhancement effects of ionizing and non-ionizing radiation on the efficiency of DNA mediated gene transfer were studied. Confluent Rat-2 cells were transfected with purified SV40 viral DNA, irradiated with either X-rays or ultraviolet, trypsinized, plated, and assayed for the formation of foci on Rat-2 monolayers. Both ionizing and ultraviolet radiation enhanced the frequency of A-gene transformants/survivor compared to unirradiated transfected cells. These enhancements were non-linear and dose dependent. A recombinant plasmid, pOT-TK5, was constructed that contained the SV40 virus A-gene and the Herpes Simplex virus (HSV) thymidine kinase (TK) gene. Confluent Rat-2 cells transfected with pOT-TK5 DNA and then immediately irradiated with either X-rays or 330 MeV/amu argon particles at the Berkeley Bevalac showed a higher frequency of HAT/sup +/ colonies/survivor than unirradiated transfected cells. Rat-2 cells transfected with the plasmid, pTK2, containing only the HSV TK-gene were enhanced for TK-transformation by both X-rays and ultraviolet radiation. The results demonstrate that radiation enhancement of the efficiency of DNA mediated gene transfer is not explained by increased nuclear uptake of the transfected DNA. Radiation increases the competence of the transfected cell population for genetic transformation. Three models for this increased competence are presented. The targeted integration model, the inducible recombination model, the partition model, and the utilization of DNA mediated gene transfer for DNA repair studies are discussed. 465 references.

Long-term efficacy of a mini-course in radiation-reducing techniques in invasive cardiology

Energy Technology Data Exchange (ETDEWEB)

Kuon, E. [Klinik Fraenkische Schweiz, Ebermannstadt (Germany). Abt. fuer Kardiologie; Empen, K.; Hummel, A.; Doerr, M.; Reffelmann, T.; Felix, S.B. [Ernst-Moritz-Arndt-Universitaet, Greifswald (Germany). Abt. fuer Innere Medizin B; Weitmann, K.; Hoffmann, W. [Ernst-Moritz-Arndt-Universitaet, Greifswald (Germany). Inst. fuer Versorgungsmedizin; Staudt, A. [Helios Kliniken, Schwerin (Germany). Abt. fuer Kardiologie und Angiologie

2013-08-15

Purpose: To validate the long-term efficacy of a 90-min. educational mini-course in less-irradiating cardiac interventional techniques. Materials and Methods: Before, two months after, and two years after the mini-course (periods I, II, and III), we analyzed the following radiation dose parameters for ten coronary angiographies (CA), performed by each of 7 cardiologists: total dose-area product (DAP), radiographic and fluoroscopic DAP fractions, number of radiographic frames and runs, and fluoroscopy time. Results: The median patient DAP for periods I, II and III was 31.4, 15.8 and 8.5 Gy x cm{sup 2}, respectively. The long-term effect was related to shorter median fluoroscopy times (180, 172, and 120 s), shorter (57, 52, and 45) and fewer (12, 12, and 10) radiographic runs, consistent collimation and restriction to an adequate image quality. Both radiographic DAP/frame (28.7, 17.0, and 18.4 mGy x cm{sup 2}) and fluoroscopic DAP/second (45.7, 24.2, and 10.0 mGy x cm{sup 2}) decreased significantly. The multivariate linear regression analysis confirmed the increasing efficacy of the mini-course itself (-44.6 and -60.7 %), and revealed a decreasing influence of the interventionalist's experience (-8.6 % and -4.9 % per 1,000 CAs, lifelong performed until the mini-course). The number of CAs performed after the mini-course did not influence the long-term DAP results. Conclusion: The presented educational mini-course allows a significant, long-lasting, and apparently ongoing reduction of patient radiation exposure due to CA. A self-surveillant documentation of relevant radiation parameters is well suited to monitor and improve each operator's individual long-term radiation-reducing efforts. (orig.)

Preclinical Data on Efficacy of 10 Drug-Radiation Combinations: Evaluations, Concerns, and Recommendations

Directory of Open Access Journals (Sweden)

Helen B. Stone

2016-02-01

Full Text Available BACKGROUND: Clinical testing of new therapeutic interventions requires comprehensive, high-quality preclinical data. Concerns regarding quality of preclinical data have been raised in recent reports. This report examines the data on the interaction of 10 drugs with radiation and provides recommendations for improving the quality, reproducibility, and utility of future studies. The drugs were AZD6244, bortezomib, 17-DMAG, erlotinib, gefitinib, lapatinib, oxaliplatin/Lipoxal, sunitinib (Pfizer, Corporate headquarters, New York, NY, thalidomide, and vorinostat. METHODS: In vitro and in vivo data were tabulated from 125 published papers, including methods, radiation and drug doses, schedules of administration, assays, measures of interaction, presentation and interpretation of data, dosimetry, and conclusions. RESULTS: In many instances, the studies contained inadequate or unclear information that would hamper efforts to replicate or intercompare the studies, and that weakened the evidence for designing and conducting clinical trials. The published reports on these drugs showed mixed results on enhancement of radiation response, except for sunitinib, which was ineffective. CONCLUSIONS: There is a need for improved experimental design, execution, and reporting of preclinical testing of agents that are candidates for clinical use in combination with radiation. A checklist is provided for authors and reviewers to ensure that preclinical studies of drug-radiation combinations meet standards of design, execution, and interpretation, and report necessary information to ensure high quality and reproducibility of studies. Improved design, execution, common measures of enhancement, and consistent interpretation of preclinical studies of drug-radiation interactions will provide rational guidance for prioritizing drugs for clinical radiotherapy trials and for the design of such trials.

Assessment of efficacy of polaprezinc suppositories against radiation-induced rectal disorders using an experimental rat model

International Nuclear Information System (INIS)

Doi, Hiroshi; Kamikonya, Norihiko; Takada, Yasuhiro

2009-01-01

The purpose/objective of this study was to establish an experimental rat model and examine the efficacy of polaprezinc suppositories against radiation-induced rectal disorders. Female Wister rats (6 weeks old) were used in the present study. The rats were divided into three groups. Group A was irradiated and medicated with polaprezinc suppositories. Group B was irradiated without any medication. Group C had no irradiation or medication. The rat was taped by the tail in the vertical position under anesthesia. Lead shielding was used to cover the rats except the area of the lower pelvis. They were irradiated at 22 Gy by a single fraction. Polaprezinc suppositories were inserted daily into the rat anus for 7 days after irradiation. All rats were evaluated by colonoscopy on the 7th day after irradiation, sacrificed on the 10th day, and evaluated for mucosal damage. In the clinical findings, the endoscopic findings, and the histological findings, the rats not administered polaprezinc suppositories tended to show more severe mucosal damage but there were no significant differences. Our study showed that this model was a useful experimental rat model for radiation-induced rectal disorders and polaprezinc suppositories demonstrated good efficacy against radiation proctitis. (author)

Enhanced sensitivity of the RET proto-oncogene to ionizing radiation in vitro.

Science.gov (United States)

Volpato, Claudia Béu; Martínez-Alfaro, Minerva; Corvi, Raffaella; Gabus, Coralie; Sauvaigo, Sylvie; Ferrari, Pietro; Bonora, Elena; De Grandi, Alessandro; Romeo, Giovanni

2008-11-01

Exposure to ionizing radiation is a well-known risk factor for a number of human cancers, including leukemia and thyroid cancer. It has been known for a long time that exposure of cells to radiation results in extensive DNA damage; however, a small number of studies have tried to explain the mechanisms of radiation-induced carcinogenesis. The high prevalence of RET/PTC rearrangements in patients who have received external radiation, and the evidence of in vitro induction of RET rearrangements in human cells, suggest an enhanced sensitivity of the RET genomic region to damage by ionizing radiation. To assess whether RET is indeed more sensitive to radiations than other genomic regions, we used a COMET assay coupled with fluorescence in situ hybridization, which allows the measurement of DNA fragmentation in defined genomic regions of single cells. We compared the initial DNA damage of the genomic regions of RET, CXCL12/SDF1, ABL, MYC, PLA2G2A, p53, and JAK2 induced by ionizing radiation in both a lymphoblastoid and a fetal thyroid cell line. In both cell lines, RET fragmentation was significantly higher than in other genomic regions. Moreover, a differential distribution of signals within the COMET was associated with a higher percentage of RET fragments in the tail. RET was more susceptible to fragmentation in the thyroid-derived cells than in lymphoblasts. This enhanced susceptibility of RET to ionizing radiation suggests the possibility of using it as a radiation exposure marker.

Radiation-enhanced diffusion in metals and alloys

International Nuclear Information System (INIS)

Lam, N.Q.; Rothman, S.J.

1975-01-01

Some phenomena that involves diffusion during irradiation include fission-product redistribution in reactor fuels, defect clustering in CTR walls or fast-reactor cladding, smearing-out of gradients in ion-implanted semiconductors, and microstructure development in a HVEM. This paper is a review of the basics of radiation-enhanced diffusion (REM). The present status of REM today is somewhat the same as diffusion in the 1940's, and recommendations are made for further work. 105 references

Self-efficacy enhancing intervention increases light physical activity in people with chronic obstructive pulmonary disease.

Science.gov (United States)

Larson, Janet L; Covey, Margaret K; Kapella, Mary C; Alex, Charles G; McAuley, Edward

2014-01-01

People with chronic obstructive pulmonary disease lead sedentary lives and could benefit from increasing their physical activity. The purpose of this study was to determine if an exercise-specific self-efficacy enhancing intervention could increase physical activity and functional performance when delivered in the context of 4 months of upper body resistance training with a 12-month follow-up. IN THIS RANDOMIZED CONTROLLED TRIAL, SUBJECTS WERE ASSIGNED TO: exercise-specific self-efficacy enhancing intervention with upper body resistance training (SE-UBR), health education with upper body resistance training (ED-UBR), or health education with gentle chair exercises (ED-Chair). Physical activity was measured with an accelerometer and functional performance was measured with the Functional Performance Inventory. Forty-nine people with moderate to severe chronic obstructive pulmonary disease completed 4 months of training and provided valid accelerometry data, and 34 also provided accelerometry data at 12 months of follow-up. The self-efficacy enhancing intervention emphasized meeting physical activity guidelines and increasing moderate-to-vigorous physical activity. Differences were observed in light physical activity (LPA) after 4 months of training, time by group interaction effect (P=0.045). The SE-UBR group increased time spent in LPA by +20.68±29.30 minutes/day and the other groups decreased time spent in LPA by -22.43±47.88 minutes/day and -25.73±51.76 minutes/day. Changes in LPA were not sustained at 12-month follow-up. There were no significant changes in moderate-to-vigorous physical activity, sedentary time, or functional performance. Subjects spent most of their waking hours sedentary: 72%±9% for SE-UBR, 68%±10% for ED-UBR, and 74%±9% for ED-Chair. The self-efficacy enhancing intervention produced a modest short-term increase in LPA. Further work is needed to increase the magnitude and duration of effect, possibly by targeting LPA.

Technologically enhanced natural radiation (TENR II). Proceedings of an international symposium

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-02-01

Natural radiation is ubiquitous. In recent decades, there has been a developing interest in fully documenting exposure of human beings to radiation of natural origin. Radiation experts have recognized that natural sources of radiation can cause exposure of members of the general public and workers to levels that warrant consideration of whether controls should be applied. The second International Symposium on Technologically Enhanced Natural Radiation (TENR II) was held in Rio de Janeiro from 12 to 17 September 1999. The objective of the symposium was to provide a forum for the international exchange of information on the scientific and technical aspects of those components of exposure to natural radiation that warrant consideration. These components were examined under the headings: the technological enhancement of natural radiation in mining and non-nuclear industries; radon indoors and outdoors; mobility and transfer of natural radionuclides; natural radiation and health effects; analytical techniques and methodologies; the remediation of contaminated sites; and regulatory and legal aspects. The symposium found that exposures to natural sources of radiation should be considered from the point of view of their amenability to control. This approach is reflected in the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS) and the associated IAEA documents on occupational exposure and rehabilitation of contaminated lands. The concepts of exclusion and intervention are particularly relevant to the amenability to control of natural sources of radiation. Indeed, the BSS specify that any exposure whose magnitude is essentially unamenable to control through the requirements of the BSS is out of the scope of the BSS. The BSS further indicate that protective or remedial actions shall be undertaken whenever they are justified in terms of the benefit to be obtained. Following their deliberations, the

Mechanisms of Enhanced Cell Killing at Low Doses: Implications for Radiation Risk

International Nuclear Information System (INIS)

Johnston, Peter J.; Wilson, George D.

2003-01-01

We have shown that cell lethality actually measured after exposure to low-doses of low-LET radiation, is markedly enhanced relative to the cell lethality previously expected by extrapolation of the high-dose cell-killing response. Net cancer risk is a balance between cell transformation and cell kill and such enhanced lethality may more than compensate for transformation at low radiation doses over a least the first 10 cGy of low-LET exposure. This would lead to a non-linear, threshold, dose-risk relationship. Therefore our data imply the possibility that the adverse effects of small radiation doses (<10 cGy) could be overestimated in specific cases. It is now important to research the mechanisms underlying the phenomenon of low-dose hypersensitivity to cell killing, in order to determine whether this can be generalized to safely allow an increase in radiation exposure limits. This would have major cost-reduction implications for the whole EM program

Chemotherapy and molecular target therapy combined with radiation therapy

International Nuclear Information System (INIS)

Akimoto, Tetsuo

2012-01-01

Combined chemotherapy and radiation therapy has been established as standard treatment approach for locally advanced head and neck cancer, esophageal cancer and so on through randomized clinical trials. However, radiation-related morbidity such as acute toxicity also increased as treatment intensity has increased. In underlining mechanism for enhancement of normal tissue reaction in chemo-radiation therapy, chemotherapy enhanced radiosensitivity of normal tissues in addition to cancer cells. Molecular target-based drugs combined with radiation therapy have been expected as promising approach that makes it possible to achieve cancer-specific enhancement of radiosensitivity, and clinical trials using combined modalities have been performed to evaluate the feasibility and efficacy of this approach. In order to obtain maximum radiotherapeutic gain, a detailed understanding of the mechanism underlying the interaction between radiation and Molecular target-based drugs is indispensable. Among molecular target-based drugs, inhibitors targeting epidermal growth factor receptor (EGFR) and its signal transduction pathways have been vigorously investigated, and mechanisms regarding the radiosensitizing effect have been getting clear. In addition, the results of randomized clinical trials demonstrated that radiation therapy combined with cetuximab resulted in improvement of overall and disease-specific survival rate compared with radiation therapy in locally advanced head and neck cancer. In this review, clinical usefulness of chemo-radiation therapy and potential molecular targets for potentiation of radiation-induced cell killing are summarized. (author)

Failure of supplementary ultraviolet radiation to enhance flower color under greenhouse conditions

Energy Technology Data Exchange (ETDEWEB)

Klein, R. M. [University of Vermont, Burlington, VT (United States)

1990-03-15

In order to determine whether the concentration of floral petal anthocyanin pigments could be increased, ultraviolet radiations in the UV-A and UV-B wavelength bands were presented to a variety of flowering plants to partly restore those wavelengths filtered out by greenhouse glass. In no tested plant did the supplementary ultraviolet radiation enhance floral anthocyanin content. Supplementary UV radiation has no economic value in greenhouse production of flowering plants. (author)

Solid lipid nanoparticle suspension enhanced the therapeutic efficacy of praziquantel against tapeworm

Directory of Open Access Journals (Sweden)

Xie S

2011-10-01

Full Text Available Shuyu Xie1,*, Baoliang Pan1,*, Baoxin Shi2, Zhuangzhi Zhang2, Xu Zhang2, Ming Wang1, Wenzhong Zhou11Department of Preventive Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, People’s Republic of China; 2Veterinary Research Institute, Xinjiang Academy of Animal Science, Xinjiang, People’s Republic of China *These authors contributed equally to this study Abstract: Hydatid disease caused by tapeworm is an increasing public health and socioeconomic concern. In order to enhance the therapeutic efficacy of praziquantel (PZQ against tapeworm, PZQ-loaded hydrogenated castor oil solid lipid nanoparticle (PZQ-HCO-SLN suspension was prepared by a hot homogenization and ultrasonication method. The stability of the suspension at 4°C and room temperature was evaluated by the physicochemical characteristics of the nanoparticles and in-vitro release pattern of the suspension. Pharmacokinetics was studied after subcutaneous administration of the suspension in dogs. The therapeutic effect of the novel formulation was evaluated in dogs naturally infected with Echinococcus granulosus. The results showed that the drug recovery of the suspension was 97.59% ± 7.56%. Nanoparticle diameter, polydispersivity index, and zeta potential were 263.00 ± 11.15 nm, 0.34 ± 0.06, and -11.57 ± 1.12 mV, respectively and showed no significant changes after 4 months of storage at both 4°C and room temperature. The stored suspensions displayed similar in-vitro release patterns as that of the newly prepared one. SLNs increased the bioavailability of PZQ 5.67-fold and extended the mean residence time of the drug from 56.71 to 280.38 hours. Single subcutaneous administration of PZQ-HCO-SLN suspension obtained enhanced therapeutic efficacy against tapeworm in infected dogs. At the dose of 5 mg/kg, the stool-ova reduction and negative conversion rates and tapeworm removal rate of the suspension were 100%, while the native PZQ were 91

Development of impurity seeding and radiation enhancement in the helical divertor of LHD

International Nuclear Information System (INIS)

Mukai, K.; Masuzaki, S.; Peterson, B.J.

2014-10-01

Impurity seeding for the reduction of the divertor heat load was conducted in the Large Helical Device (LHD) using neon (Ne) and krypton (Kr) puffing. Enhanced radiation loss and reduction of the divertor heat load were observed without significant changes in stored energy and line averaged density. In the LHD, the radiated power fraction of the heating power, P rad /P heating , where P rad and P heating are the total radiation power and the heating power, respectively, is limited up to around 30% in hydrogen plasmas even for high density plasma just below the radiative collapse (n e,bar > 1 × 10 20 m -3 ), where n e,bar is the line averaged density. With Ne seeding, the ratio could be raised to 52% in spite of much lower density (n e,bar ∼ 1.3 × 10 19 m -3 ), albeit with a slight reduction in confinement. P rad /P heating ∼ 30% could be sustained for 3.4 s using multi-pulse Ne seeding in relatively high density plasmas in this study (n e,bar ∼ 4 × 10 19 m -3 ). Radiation profile measurement with an InfraRed Imaging Video Bolometer (IRVB) was conducted during Ne seeding. The localized supplemental radiation was observed along the helical divertor X-points (HDXs). The enhanced radiation structure was similar to the Ne radiation profile estimated by EMC3-EIRENE code. Kr seeding was also conducted to the plasma of n e,bar ∼ 3.1 × 10 19 m -3 . P rad /P heating ∼ 25% was obtained without significant change in stored energy. The enhancement of the plasma radiation has a slower time constant compared with the Ne seeding. The supplemental radiation area of the Kr seeded plasma moved from the HDXs to the core plasma. High-valent Kr ions are considered to be the dominant radiators from the plasma core region. (author)

Radiation enhanced reactivation of irradiated human adenovirus type 2 in human cells

International Nuclear Information System (INIS)

Jeeves, W.P.

1981-04-01

Radiation-enhanced reactivation (ER) of a radiation-damaged mammalian virus is the term given to the observation that the survival of irradiated virus can be enhanced by irradiation of an appropriate host cell prior to infection. In this work, both UV-enhanced reactivation (UVER) and gamma-ray-enhanced reactivation (γRER) of irradiated human adenovirus type 2 (AD 2) were studied in a variety of normal and DNA repair-deficient human fibroblast host cell strains. In order to examine the lesion specificity of ER in human cells, experiments were performed using UV-irradiated and γ-irradiated virus. The investigation was carried out using a sensitive technique of indirect immunofluorescence, according to which irradiated and unirradiated cell cultures were infected with irradiated or unirradiated AD 2 and were subsequently examined for the presence of viral structural antigens ('V' Ag) at a fixed time after infection

Radiation enhanced diffusion in FCC alloys

International Nuclear Information System (INIS)

Schuele, W.

1982-01-01

In many alloys vacancies and interstitials can be identified in a straight forward way by measurements of radiation enhanced diffusion. In some alloys, however, quenching experiments are also necessary for the identification of these defects. Results for two characteristic alloys in which the transformation rate during high energy particle irradiation is determined by an interstitialcy and by a vacancy diffusion mechanism only, are discussed. It is also shown that a decrease of the migration energy of defects due to an interaction of the high energy particles with the lattice atoms must be taken into account in the interpretation of the results. (author)

The anti-epidermal growth factor receptor (EGFR) monoclonal antibody, C225, enhances radiation-induced apoptosis in primary glioma cell lines through mediation of MAPK/JNK/p38 signaling pathways

International Nuclear Information System (INIS)

Chakravarti, A.; Noll, E.; Black, P.M.; Loeffler, J.S.

2001-01-01

Purpose: Increasing evidence suggests that signaling mediated by the epidermal growth factor receptor (EGFR) pathway contributes to radiation resistance. The anti-EGFR monoclonal antibody, C225, has been shown to enhance radiation response for several tumor types in preclinical models. Malignant gliomas are known to express, and quite frequently overexpress, EGFR. Our objectives in this study were to 1) Evaluate the efficacy of C225 as a radiation response modifier in EGFR-expressing glioma cell lines and to 2) Investigate the underlying molecular mechanisms mediating C225-induced enhancement of radiation response. Materials and Methods: Twelve EGFR-expressing glioma cells lines, established from patient tumors, were used for this study. Cells were incubated with C225, irradiated, and then evaluated for radiation response. Assays used to evaluate efficacy of C225-mediated radiosensitization included time-course apoptosis assays (Annexin V and TUNEL), viability assays (MTT), and clonogenic survival assays. The changes along MAPK (p44/p42)/JNK/p38-MAPK signal transduction pathways were then investigated using quantitative Western analysis with phospho-specific antibodies to determine the molecular mechanisms by which C225 mediates a given response. Results: C225 clearly enhanced radiation response for 7 of the 12 primary glioma cell lines studied. Enhancement of both immediate and delayed apoptotic responses was evident in these 7 responsive cell lines after C225 administration. The average apoptosis index at 6 hours post-RT+C225 for the 7 responsive lines was 9.5%, compared to 1.2% for the RT-only controls. A pattern of delayed apoptosis was evident in these 7 lines, with secondary apoptotic peaks (∼ 8.0%) occurring at 24 hours post-RT+C225. Time course viability measurements revealed a steady decrease in viable tumor cells in these responsive cell lines from 75% at 6 hours post-RT+C225 to 20% at 7 days. Clonogenic survival was also diminished in these 7 lines

Fabrication and characterization of UV-emitting nanoparticles as novel radiation sensitizers targeting hypoxic tumor cells

Science.gov (United States)

Squillante, Michael R.; Jüstel, Thomas; Anderson, R. Rox; Brecher, Charles; Chartier, Daniel; Christian, James F.; Cicchetti, Nicholas; Espinoza, Sara; McAdams, Daniel R.; Müller, Matthias; Tornifoglio, Brooke; Wang, Yimin; Purschke, Martin

2018-06-01

Radiation therapy is one of the primary therapeutic techniques for treating cancer, administered to nearly two-thirds of all cancer patients. Although largely effective in killing cancer cells, radiation therapy, like other forms of cancer treatment, has difficulty dealing with hypoxic regions within solid tumors. The incomplete killing of cancer cells can lead to recurrence and relapse. The research presented here is investigating the enhancement of the efficacy of radiation therapy by using scintillating nanoparticles that emit UV photons. UV photons, with wavelengths between 230 nm and 280 nm, are able to inactivate cells due to their direct interaction with DNA, causing a variety of forms of damage. UV-emitting nanoparticles will enhance the treatment in two ways: first by generating UV photons in the immediate vicinity of cancer cells, leading to direct and oxygen-independent DNA damage, and second by down-converting the applied higher energy X-rays into softer X-rays and particles that are more efficiently absorbed in the targeted tumor region. The end result will be nanoparticles with a higher efficacy in the treatment of hypoxic cells in the tumor, filling an important, unmet clinical need. Our preliminary experiments show an increase in cell death using scintillating LuPO4:Pr nanoparticles over that achieved by the primary radiation alone. This work describes the fabrication of the nanoparticles, their physical characterization, and the spectroscopic characterization of the UV emission. The work also presents in vitro results that demonstrate an enhanced efficacy of cell killing with x-rays and a low unspecific toxicity of the nanoparticles.

Enhanced radiative strength in the quasicontinuum of 117Sn.

Science.gov (United States)

Agvaanluvsan, U; Larsen, A C; Chankova, R; Guttormsen, M; Mitchell, G E; Schiller, A; Siem, S; Voinov, A

2009-04-24

The radiative strength function of 117Sn has been measured up to the neutron separation energy using the (3He, 3He' gamma) reaction. An increase in the slope of the strength function around E gamma=4.5 MeV indicates the onset of a resonancelike structure, giving a significant enhancement of the radiative strength function compared to standard models in the energy region 4.5

Materials That Enhance Efficiency and Radiation Resistance of Solar Cells

Science.gov (United States)

Sun, Xiadong; Wang, Haorong

2012-01-01

A thin layer (approximately 10 microns) of a novel "transparent" fluorescent material is applied to existing solar cells or modules to effectively block and convert UV light, or other lower solar response waveband of solar radiation, to visible or IR light that can be more efficiently used by solar cells for additional photocurrent. Meanwhile, the layer of fluorescent coating material remains fully "transparent" to the visible and IR waveband of solar radiation, resulting in a net gain of solar cell efficiency. This innovation alters the effective solar spectral power distribution to which an existing cell gets exposed, and matches the maximum photovoltaic (PV) response of existing cells. By shifting a low PV response waveband (e.g., UV) of solar radiation to a high PV response waveband (e.g. Vis-Near IR) with novel fluorescent materials that are transparent to other solar-cell sensitive wavebands, electrical output from solar cells will be enhanced. This approach enhances the efficiency of solar cells by converting UV and high-energy particles in space that would otherwise be wasted to visible/IR light. This innovation is a generic technique that can be readily implemented to significantly increase efficiencies of both space and terrestrial solar cells, without incurring much cost, thus bringing a broad base of economical, social, and environmental benefits. The key to this approach is that the "fluorescent" material must be very efficient, and cannot block or attenuate the "desirable" and unconverted" waveband of solar radiation (e.g. Vis-NIR) from reaching the cells. Some nano-phosphors and novel organometallic complex materials have been identified that enhance the energy efficiency on some state-of-the-art commercial silicon and thin-film-based solar cells by over 6%.

The vitamin-like dietary supplement para-aminobenzoic acid enhances the antitumor activity of ionizing radiation

International Nuclear Information System (INIS)

Xavier, Sandhya; MacDonald, Shannon; Roth, Jennifer; Caunt, Maresa; Akalu, Abebe; Morais, Danielle; Buckley, Michael T.; Liebes, Leonard; Formenti, Silvia C.; Brooks, Peter C.

2006-01-01

Purpose: To determine whether para-aminobenzoic acid (PABA) alters the sensitivity of tumor cells to ionizing radiation in vitro and in vivo. Methods and Materials: Cellular proliferation was assessed by WST-1 assays. The effects of PABA and radiation on tumor growth were examined with chick embryo and murine models. Real-time reverse transcriptase-polymerase chain reaction and Western blotting were used to quantify p21 CIP1 and CDC25A levels. Results: Para-aminobenzoic acid enhanced (by 50%) the growth inhibitory activity of radiation on B16F10 cells, whereas it had no effect on melanocytes. Para-aminobenzoic acid enhanced (50-80%) the antitumor activity of radiation on B16F10 and 4T1 tumors in vivo. The combination of PABA and radiation therapy increased tumor apoptosis. Treatment of tumor cells with PABA increased expression of CDC25A and decreased levels of p21 CIP1 . Conclusions: Our findings suggest that PABA might represent a compound capable of enhancing the antitumor activity of ionizing radiation by a mechanism involving altered expression of proteins known to regulate cell cycle arrest

HIV enhancing activity of semen impairs the antiviral efficacy of microbicides

Science.gov (United States)

Zirafi, Onofrio; Kim, Kyeong-Ae; Roan, Nadia R.; Kluge, Silvia F.; Müller, Janis A.; Jiang, Shibo; Mayer, Benjamin; Greene, Warner C.; Kirchhoff, Frank; Münch, Jan

2015-01-01

Topically applied microbicides potently inhibit HIV in vitro but have largely failed to exert protective effects in clinical trials. One possible reason for this discrepancy is that the preclinical testing of microbicides does not faithfully reflect the conditions of HIV sexual transmission. Here, we report that candidate microbicides that target HIV components show greatly reduced antiviral efficacy in the presence of semen, the main vector for HIV transmission. This diminished antiviral activity was dependent on the ability of amyloid fibrils in semen to enhance the infectivity of HIV. Thus, the anti-HIV efficacy of microbicides determined in the absence of semen greatly underestimated the drug concentrations needed to block semen-exposed virus. One notable exception was Maraviroc. This HIV entry inhibitor targets the host cell CCR5 coreceptor and was highly active against both untreated and semen-exposed HIV. These data help explain why microbicides have failed to protect against HIV in clinical trials and suggest that antiviral compounds targeting host factors hold promise for further development. These findings also suggest that the in vitro efficacy of candidate microbicides should be determined in the presence of semen to identify the best candidates for the prevention of HIV sexual transmission. PMID:25391483

Some technologically enhanced exposures to natural radiation environment in India

International Nuclear Information System (INIS)

Lalit, B.Y.; Shukla, V.K.; Ramachandran, T.V.; Mishra, U.C.

1982-01-01

A summary of results of gamma spectrometric measurements of natural radioactivity in a number of coal and flyash samples from thermal power plants and phosphatic fertilizer samples collected from various fertilizer plants in India are presented. These constitute the sources of technologically enhanced exposures to natural radiation. A brief description of sampling and measurement procedures is given. The radiation doses to the population from coal burning for electricity generation have been calculated using the method outlined in UNSCEAR report of 1979 with corrections for local population density. The external radiation dose to the farmers has been calculated on the basis of usage of phosphatic fertilizers for rice, wheat, millets and sugarcane crops for the normal agricultural practices

Safety and clinical efficacy of some radiation-sterilized medical products and pharmaceuticals

International Nuclear Information System (INIS)

Kulkarni, R.D.; Gopal, N.G.S.

1975-01-01

Medical products and pharmaceuticals must conform to certain minimum physico-chemical microbiological and biological requirements. The biological requirements comprise principally testing for toxicity, safety, and pyrogens. Besides the above-mentioned criteria, there are two other important characteristics, viz. clinical efficacy and tolerance in animal and/or human beings. These latter requirements, expected from the final product released for general human use, are not carried out routinely. In the present-day pharmaceutical and medical technology, numerous mew products are appearing, many of them requiring radiation sterilization as they are not stable towards the other conventional methods of sterilization. While the post-irradiation physicochemical changes in a product may not be significant, the bio-availability or biological activity of the product may be affected to a more significant extent. Some evidence of this has recently been reported. Hence, it is desirable to carry out studies on safety as well as clinical efficacy on irradiated products. This paper describes some studies on plastic-based medical products, a pharmaceutical raw material, a typical infusion fluid such as normal saline, antibiotics and their ointments. (author)

Radiation treatment in older patients: a framework for clinical decision making.

Science.gov (United States)

Smith, Grace L; Smith, Benjamin D

2014-08-20

In older patients, radiation treatment plays a vital role in curative and palliative cancer therapy. Radiation treatment recommendations should be informed by a comprehensive, personalized risk-benefit assessment that evaluates treatment efficacy and toxicity. We review several clinical factors that distinctly affect efficacy and toxicity of radiation treatment in older patients. First, locoregional tumor behavior may be more indolent in older patients for some disease sites but more aggressive for other sites. Assessment of expected locoregional relapse risk informs the magnitude and timeframe of expected radiation treatment benefits. Second, assessment of the competing cancer versus noncancer mortality and morbidity risks contextualizes cancer treatment priorities holistically within patients' entire spectrum and time course of health needs. Third, assessment of functional reserve helps predict patients' acute treatment tolerance, differentiating those patients who are unlikely to benefit from treatment or who are at high risk for treatment complications. Potential radiation treatment options include immediate curative treatment, delayed curative treatment, and no treatment, with additional consideration given to altered radiation target, dose, or sequencing with chemotherapy and/or surgery. Finally, when cure is not feasible, palliative radiation therapy remains valuable for managing symptoms and achieving meaningful quality-of-life improvements. Our proposed decision-making framework integrates these factors to help radiation oncologists formulate strategic treatment recommendations within a multidisciplinary context. Future research is still needed to identify how advanced technologies can be judiciously applied in curative and palliative settings to enhance risk-benefit profiles of radiation treatment in older patients and more accurately quantify treatment efficacy in this group. © 2014 by American Society of Clinical Oncology.

Enhancement of radiation cytotoxicity by gold nanoparticles in MCF-7 breast cancer cell lines

Energy Technology Data Exchange (ETDEWEB)

Rosli, Nur Shafawati binti; Rahman, Azhar Abdul [School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); Aziz, Azlan Abdul [School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); Shamsuddin, Shaharum [Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); School of Health Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

2015-04-24

Therapy combined with metallic nanoparticles is a new way to treat cancer, in which gold nanoparticles (AuNPs) are injected through intravenous administration and bound to tumor sites. Radiotherapy aims to deliver a high therapeutic dose of ionizing radiation to the tumor without exceeding normal tissue tolerance. The use of AuNPs which is a high-atomic-number (Z) material in radiotherapy will provide a high probability for photon interaction by photoelectric effect. These provide advantages in terms of radiation dose enhancement. The high linear energy transfer and short range of photoelectric interaction products (photoelectrons, characteristic x-rays, Auger electrons) produce localized dose enhancement of the tumor. In this work, breast cancer cell lines (MCF-7) are seeded in the 96-well plate and were treated with 13 nm AuNPs before they were irradiated with 6 MV and 10 MV photon beam from a medical linear accelerator at various radiation doses. To validate the enhanced killing effect, both with and without AuNPs MCF-7 cells is irradiated simultaneously. By comparison, the results show that AuNPs significantly enhance cancer killing.

Efficacy of gadolinium enhanced MR imaging for the diagnosis of Legg-Calve-Perthes disease

International Nuclear Information System (INIS)

Kim, Jee Eun; Kim, Hyung Sik; Kim, Ji Hye

2008-01-01

The purpose of this study was to evaluate the efficacy of gadolinium enhanced MR imaging for making the diagnosis of Legg-Calve-Perthes (LCP) disease. We studied the gadolinium enhanced MR images of 14 hips in 12 children who had the diagnosis of LCP disease. We retrospectively analyzed the extent of necrosis, the epiphyseal revascularization pathways and the metaphyseal changes. The absence of enhancement on gadolinium enhanced MRI was noted in all cases of LCP disease. Diffuse absence of enhancement was observed in 9 femoral epiphyses. Two of them showed normal bone marrow signal intensity on the T1 and T1-weighted images. Focal absence of enhancement was observed in 5 femoral epiphyses. Enhanced MRI showed better epiphyseal revascularization in the lateral column (five cases), in the lateral and medial columns (four cases) and in the transphyseal pathway (three cases). Metaphyseal change was observed in two cases. Gadolinium enhanced MRI allows detection of LCP disease and an accurate analysis of the different revascularization patterns, and this helpful for predicting the prognosis

Enhanced radiative Auger emission from lithiumlike 16S13+

International Nuclear Information System (INIS)

Bernstein, E.M.; Clark, M.W.; Oglesby, C.S.; Tanis, J.A.; Graham, W.G.; McFarland, R.H.; Morgan, T.J.; Johnson, B.M.; Jones, K.W.

1990-01-01

The radiative Auger emission (RAE) from 0.94--6.25-MeV/u 16 S 13+ (lithiumlike) projectiles excited in collisions with He target atoms has been measured. For these highly stripped ions the intensity of RAE photons relative to Kα x-ray emission is enhanced by about a factor of five compared with theoretical calculations and an earlier experimental measurement for S ions with few electron vacancies. The enhancement of RAE for S 13+ is qualitatively similar to results reported previously for lithiumlike 23 V 20+ ; however, some differences between S and V are evident

Enhancing the Therapeutic Efficacy of Cancer Treatment With Cannabinoids

Directory of Open Access Journals (Sweden)

Sayeda Yasmin-Karim

2018-04-01

Full Text Available Over the years, many in vitro and in vivo studies have shown the antineoplastic effects of cannabinoids (CBDs, with reports advocating for investigations of combination therapy approaches that could better leverage these effects in clinical translation. This study explores the potential of combination approaches employing CBDs with radiotherapy (RT or smart biomaterials toward enhancing therapeutic efficacy during treatment of pancreatic and lung cancers. In in vitro studies, clonogenic assay results showed greater effective tumor cell killing, when combining CBDs and RT. Meanwhile, in vivo study results revealed major increase in survival when employing smart biomaterials for sustained delivery of CBDs to tumor cells. The significance of these findings, considerations for further research, and viable roadmap to clinical translation are discussed.

Enhanced therapeutic effect of multiple injections of HSV-TK + GCV gene therapy in combination with ionizing radiation in a mouse mammary tumor model

International Nuclear Information System (INIS)

Vlachaki, Maria T.; Chhikara, Madhu; Aguilar, Laura; Zhu Xiaohong; Chiu, Kam J.; Woo, Shiao; Teh, Bin S.; Thompson, Timothy C.; Butler, E. Brian; Aguilar-Cordova, Estuardo

2001-01-01

Purpose: Standard therapies for breast cancer lack tumor specificity and have significant risk for recurrence and toxicities. Herpes simplex virus-thymidine kinase (HSV-tk) gene therapy combined with radiation therapy (XRT) may be effective because of complementary mechanisms and distinct toxicity profiles. HSV-tk gene therapy followed by systemic administration of ganciclovir (GCV) enhances radiation-induced DNA damage by generating high local concentrations of phosphorylated nucleotide analogs that increase radiation-induced DNA breaks and interfere with DNA repair mechanisms. In addition, radiation-induced membrane damage enhances the 'bystander effect' by facilitating transfer of nucleotide analogs to neighboring nontransduced cells and by promoting local and systemic immune responses. This study assesses the effect of single and multiple courses of HSV-tk gene therapy in combination with ionizing radiation in a mouse mammary cancer model. Methods and Materials: Mouse mammary TM40D tumors transplanted s.c. in syngeneic immunocompetent BALB-c mice were treated with either adenoviral-mediated HSV-tk gene therapy or local radiation or the combination of gene and radiation therapy. A vector consisting of a replication-deficient (E1-deleted) adenovirus type 5 was injected intratumorally to administer the HSV-tk gene, and GCV was initiated 24 h later for a total of 6 days. Radiation was given as a single dose of 5 Gy 48 h after the HSV-tk injection. A metastatic model was developed by tail vein injection of TM40D cells on the same day that the s.c. tumors were established. Systemic antitumor effect was evaluated by counting the number of lung nodules after treating only the primary tumors with gene therapy, radiation, or the combination of gene and radiation therapy. To assess the therapeutic efficacy of multiple courses of this combinatorial approach, one, two, and three courses of HSV-tk + GCV gene therapy, in combination with radiation, were compared to HSV-tk or

Enhanced antitumor efficacy of cisplatin in combination with HemoHIM in tumor-bearing mice

Directory of Open Access Journals (Sweden)

Kim Sung-Ho

2009-03-01

Full Text Available Abstract Background Although cisplatin is one of the most effective chemotherapeutic agents, cisplatin alone does not achieve a satisfactory therapeutic outcome. Also cisplatin accumulation shows toxicity to normal tissues. In this study, we examined the possibility of HemoHIM both to enhance anticancer effect with cisplatin and to reduce the side effects of cisplatin in melanoma-bearing mice. Methods HemoHIM was prepared by adding the ethanol-insoluble fraction to the total water extract of a mixture of 3 edible herbs, Angelica Radix, Cnidium Rhizoma and Paeonia Radix. Anticancer effects of HemoHIM with cisplatin were evaluated in melanoma-bearing mice. We used a Cr51-release assay to measure the activity of NK/Tc cell and ELISA to evaluate the production of cytokines. Results In melanoma-bearing mice, cisplatin (4 mg/kg B.W. reduced the size and weight of the solid tumors, and HemoHIM supplementation with cisplatin enhanced the decrease of both the tumor size (p in vitro, and did not disturb the effects of cisplatin in vitro. However HemoHIM administration enhanced both NK cell and Tc cell activity in mice. Interestingly, HemoHIM increased the proportion of NK cells in the spleen. In melanoma-bearing mice treated with cisplatin, HemoHIM administration also increased the activity of NK cells and Tc cells and the IL-2 and IFN-γ secretion from splenocytes, which seemed to contribute to the enhanced efficacy of cisplatin by HemoHIM. Also, HemoHIM reduced nephrotoxicity as seen by tubular cell of kidney destruction. Conclusion HemoHIM may be a beneficial supplement during cisplatin chemotherapy for enhancing the anti-tumor efficacy and reducing the toxicity of cisplatin.

Caffeine enhancement of radiation killing in different strains of Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Hannan, M.A.; Nasim, A.

1977-01-01

Haploid and diploid wild type strains, and three classes of radiation-sensitive mutants of Saccharomyces cerrevisiae were tesed for enhancement of UV-inactivation by caffeine in growth medium. In addition the sensitizing effect of caffeine was studied in a haploid and a diploid wild type strain after gamma-irradiation. The drug sensitized the UV-irradiated cells of all strains except those reported to be only slightly UV-sensitive but highly sensitive to ionizing radiation. After gamma-irradiation, no coffeine-enhancement of killing was observed in stationary phase cells of either the haploid or the diploid strain. However, log-phase cells of both strains were partially sensitized. The results of both sets of experiments suggested that caffeine interferes with a recombinational repair occurring in cells in S or G2 phase. (orig.) [de

The virtual enhancements - solar proton event radiation (VESPER) model

Science.gov (United States)

Aminalragia-Giamini, Sigiava; Sandberg, Ingmar; Papadimitriou, Constantinos; Daglis, Ioannis A.; Jiggens, Piers

2018-02-01

A new probabilistic model introducing a novel paradigm for the modelling of the solar proton environment at 1 AU is presented. The virtual enhancements - solar proton event radiation model (VESPER) uses the European space agency's solar energetic particle environment modelling (SEPEM) Reference Dataset and produces virtual time-series of proton differential fluxes. In this regard it fundamentally diverges from the approach of existing SPE models that are based on probabilistic descriptions of SPE macroscopic characteristics such as peak flux and cumulative fluence. It is shown that VESPER reproduces well the dataset characteristics it uses, and further comparisons with existing models are made with respect to their results. The production of time-series as the main output of the model opens a straightforward way for the calculation of solar proton radiation effects in terms of time-series and the pairing with effects caused by trapped radiation and galactic cosmic rays.

Using Acetaminophen's Toxicity Mechanism to Enhance Cisplatin Efficacy in Hepatocarcinoma and Hepatoblastoma Cell Lines

Directory of Open Access Journals (Sweden)

Alexander J. Neuwelt

2009-10-01

Conclusions: Our results suggest that a chemotherapeutic regimen containing both AAP and CDDP with delayed NAC rescue has the potential to enhance chemotherapeutic efficacy while decreasing adverse effects. This would be a promising approach particularly for hepatoblastomas regardless of cellular CYP2E1 protein level but could also be beneficial in other malignancies.

Malignant Esophagogastric Junction Obstruction: Efficacy of Balloon Dilation Combined with Chemotherapy and/or Radiation Therapy

International Nuclear Information System (INIS)

Ko, Gi-Young; Song, Ho-Young; Hong, Heuk-Jin; Sung, Kyu-Bo; Seo, Tae-Seok; Yoon, Hyun-Ki

2003-01-01

Purpose: To assess the efficacy of balloon dilation combined with chemotherapy and/or radiation therapy for palliation of dysphagia due to malignant esophagogastric junction strictures. Methods: Fluoroscopically guided balloon dilation was attempted in 20 patients. The causes of strictures were gastric adenocarcinoma (n = 10) and esophageal squamous cell carcinoma (n = 10). Scheduled chemotherapy and/or radiation therapy followed balloon dilation in all patients. Results: There were no technical failures or major complications. After balloon dilation, 15 (75%) patients showed improvement of dysphagia. No patient complained of reflux esophagitis during the follow-up period. Among the 15 patients, seven needed no further treatment for palliation of dysphagia until their deaths. The remaining eight patients underwent repeat balloon dilation(n = 4) or stent placement (n = 4)3-43 weeks (mean 15 weeks) after the initial balloon dilation because of recurrent dysphagia. Conclusion: Balloon dilation combined with chemotherapy and/or radiation therapy seems to be an easy and reasonably effective palliative treatment for malignant esophagogastric strictures

Radiation enhanced reactivation of nuclear replicating mammalian viruses

International Nuclear Information System (INIS)

Bockstahler, L.E.; Lytle, C.D.

1977-01-01

When CV-1 monkey kidney cells were UV-irradiated (0 to 18 J/m 2 ) or X-irradiated (0 to 10 krads) before infection with UV-irradiated simian adenovirus 7 (SA7) or simian virus 40 (SV40), increases in the infectivity of these nuclear replicating viruses as measured by plaque formation were observed. These radiation enhanced reactivations, UV enhanced reactivation (UVER) and X-ray enhanced reactivation (X-ray ER), occurred both when virus infection immediately followed irradiation of the cells (except for X-ray ER with SA7) and when virus infection was delayed until 3 to 5 days after cell irradiation. While there was little difference in the levels of reactivation of UV-irradiated SV40 between immediate and delayed infection, delayed infection resulted in higher levels of reactivation of SA7. X-ray enhanced reactivation of UV-irradiated Herpes simplex virus persisted for several days but did not increase. Thus, X-ray enhanced and UV enhanced reactivations of these mammalian viruses were relatively long-lived effects. Essentially no UVER or X-ray ER was found in CV-1 cells for either immediate or delayed infection with UV-irradiated vaccinia virus or poliovirus, both of which replicate in the cell cytoplasm. These results suggest UVER and X-ray ER in mammalian cells may be restricted to viruses which are replicated in the cell nucleus. (author)

The Effectiveness of Group Motivational Interviewing Sessions on Enhancing of Addicted Women’s Self-Esteem and Self Efficacy

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Samireh Dehghani F

2013-07-01

Full Text Available Objective: The aim of present research was to study of the effectiveness of motivational interviewing on enhancing of self-esteem and self-efficacy in addicted women who were under therapy. Method: The research method was semi experimental research design namely: pretest-posttest with witness group. The population consisted of all addicted women who were referred to Ayandeh Roshan recovery addiction camp of Isfahan city during summer in 1391. By available sampling, 30 women selected and divided randomly to two experimental and witness groups (N= 15, per group. Experimental group received eight sessions of 90 minutes based on group counseling sessions following motivational interviewing style. For gathering data, Cooper Smith’s self-esteem and general self-efficacy questionnaires administered among two groups. Results: The results indicated the effectiveness of motivational interviewing. Conclusion: It can be concluded that motivational interviewing has had enhancing effect on self-esteem and self-efficacy among experimental group.

Enhancing the hermeneutic single-case efficacy design: Bridging the research-practice gap.

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Wall, Jessie M; Kwee, Janelle L; Hu, Monica; McDonald, Marvin J

2017-09-01

Systematic case study designs are emerging as alternative paradigm strategies for psychotherapy and social science research. Through enhanced sensitivity to context, these designs examine idiographic profiles of causal processes. We specifically advocate the use of the hermeneutic single-case efficacy design (HSCED). HSCED has recently been used to investigate the efficacy of an existing therapy with a new population (Observed and Experiential Integration for athlete performance barriers) and an emerging therapy (Lifespan Integration Therapy). We describe innovations in HSCED that were implemented for these studies. These developments include (a) integrating psychotherapists as case developers, (b) incorporating multiple cases in one investigation, and (c) tailoring the repertoire of assessment tools. These extensions strategically incorporated principles of contextual paradigms in HSCED, thus complementing single-case designs that neglect idiographic contexts. We discuss recommendations for using HSCED in practice-based research, highlighting its potential as a bridge to address the research-practice gap.

Contrast-enhanced spectral mammography based on a photon-counting detector: quantitative accuracy and radiation dose

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Lee, Seungwan; Kang, Sooncheol; Eom, Jisoo

2017-03-01

Contrast-enhanced mammography has been used to demonstrate functional information about a breast tumor by injecting contrast agents. However, a conventional technique with a single exposure degrades the efficiency of tumor detection due to structure overlapping. Dual-energy techniques with energy-integrating detectors (EIDs) also cause an increase of radiation dose and an inaccuracy of material decomposition due to the limitations of EIDs. On the other hands, spectral mammography with photon-counting detectors (PCDs) is able to resolve the issues induced by the conventional technique and EIDs using their energy-discrimination capabilities. In this study, the contrast-enhanced spectral mammography based on a PCD was implemented by using a polychromatic dual-energy model, and the proposed technique was compared with the dual-energy technique with an EID in terms of quantitative accuracy and radiation dose. The results showed that the proposed technique improved the quantitative accuracy as well as reduced radiation dose comparing to the dual-energy technique with an EID. The quantitative accuracy of the contrast-enhanced spectral mammography based on a PCD was slightly improved as a function of radiation dose. Therefore, the contrast-enhanced spectral mammography based on a PCD is able to provide useful information for detecting breast tumors and improving diagnostic accuracy.

An HDAC-dependent epigenetic mechanism that enhances the efficacy of the antidepressant drug fluoxetine

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Schmauss, C.

2015-01-01

Depression is a prevalent and debilitating psychiatric illnesses. However, currently prescribed antidepressant drugs are only efficacious in a limited group of patients. Studies on Balb/c mice suggested that histone deacetylase (HDAC) inhibition may enhance the efficacy of the widely-prescribed antidepressant drug fluoxetine. This study shows that reducing HDAC activity in fluoxetine-treated Balb/c mice leads to robust antidepressant and anxiolytic effects. While reducing the activity of class I HDACs 1 and 3 led to antidepressant effects, additional class II HDAC inhibition was necessary to exert anxiolytic effects. In fluoxetine-treated mice, HDAC inhibitors increased enrichment of acetylated histone H4 protein and RNA polymerase II at promotor 3 of the brain-derived neurotrophic factor (Bdnf) gene and increased Bdnf transcription from this promotor. Reducing Bdnf-stimulated tropomyosin kinase B receptor activation in fluoxetine-treated mice with low HDAC activity abolished the behavioral effects of fluoxetine, suggesting that the HDAC-triggered epigenetic stimulation of Bdnf expression is critical for therapeutic efficacy. PMID:25639887

[Study of enhancement effect of laser-induced crater on plasma radiation].

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Chen, Jin-Zhong; Zhang, Xiao-Ping; Guo, Qing-Lin; Su, Hong-Xin; Li, Guang

2009-02-01

Single pulses exported from high-energy neodymium glass laser were used to act on the same position of soil sample surface repeatedly, and the plasma emission spectra generated from sequential laser pulse action were collected by spectral recording system. The experimental results show that the laser-induced soil plasma radiation was enhanced continuously under the confinement effect of the crater walls, and the line intensities and signal-to-background ratios both had different improvements along with increasing the number of acting pulses. The photographs of the plasma image and crater appearance were taken to study the plasma shape, laser-induced crater appearance, and the mass of the ablated sample. The internal mechanism behind that laser-induced crater enhanced plasma radiation was researched. Under the sequential laser pulse action, the forming plasma as a result enlarges gradually first, leading to distortion at the trail of plasma plume, and then, its volume diminishes slowly. And also, the color of the plasma changes from buff to white gradually, which implies that the temperature increases constantly. The laser-induced crater had a regular shape, that is, the diameter increased from its bottom to top gradually, thus forming a taper. The mass of the laser-ablated substance descends along with increasing the amount of action pulse. Atomization degree of vaporized substance was improved in virtue of the crater confinement effect, Fresnel absorption produced from the crater walls reflection, and the inverse bremsstrahlung, and the plasma radiation intensity was enhanced as a result.

Investigation of radiation-enhanced oxygen diffusion in Li-Ti ferrites

International Nuclear Information System (INIS)

Surzhikov, A.P.; Pritulov, A.M.; Gyngazov, S.A.; Lysenko, E.N.

1999-01-01

The radiation-enhanced oxygen diffusion in polycrystalline Li-Ti ferrites was investigated. The electron accelerator ELV-6 (Institute of Nuclear Physics, Russian Academy of Sciences) was used to generate the radiothermal annealing. The radiation effects were established by comparison of diffusion profiles of the samples, which were radiothermally treated, and data obtained during the thermal annealing in the resistance furnace. It was discovered that there was an increase of numerical values of Ed (activation diffusion energy) and Do (preexponential factor) during the radiothermal annealing, if compared with the thermal one. The investigations were financed by the Russian Fundamental Research Fund

Genetic incorporation of the protein transduction domain of Tat into Ad5 fiber enhances gene transfer efficacy

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Siegal Gene P

2007-10-01

Full Text Available Abstract Background Human adenovirus serotype 5 (Ad5 has been widely explored as a gene delivery vector for a variety of diseases. Many target cells, however, express low levels of Ad5 native receptor, the Coxsackie-Adenovirus Receptor (CAR, and thus are resistant to Ad5 infection. The Protein Transduction Domain of the HIV Tat protein, namely PTDtat, has been shown to mediate protein transduction in a wide range of cells. We hypothesize that re-targeting Ad5 vector via the PTDtat motif would improve the efficacy of Ad5-mediated gene delivery. Results In this study, we genetically incorporated the PTDtat motif into the knob domain of Ad5 fiber, and rescued the resultant viral vector, Ad5.PTDtat. Our data showed the modification did not interfere with Ad5 binding to its native receptor CAR, suggesting Ad5 infection via the CAR pathway is retained. In addition, we found that Ad5.PTDtat exhibited enhanced gene transfer efficacy in all of the cell lines that we have tested, which included both low-CAR and high-CAR decorated cells. Competitive inhibition assays suggested the enhanced infectivity of Ad5.PTDtat was mediated by binding of the positively charged PTDtat peptide to the negatively charged epitopes on the cells' surface. Furthermore, we investigated in vivo gene delivery efficacy of Ad5.PTDtat using subcutaneous tumor models established with U118MG glioma cells, and found that Ad5.PTDtat exhibited enhanced gene transfer efficacy compared to unmodified Ad5 vector as analyzed by a non-invasive fluorescence imaging technique. Conclusion Genetic incorporation of the PTDtat motif into Ad5 fiber allowed Ad5 vectors to infect cells via an alternative PTDtat targeting motif while retaining the native CAR-mediated infection pathway. The enhanced infectivity was demonstrated in both cultured cells and in in vivo tumor models. Taken together, our study identifies a novel tropism expanded Ad5 vector that may be useful for clinical gene therapy

The efficacy of a brief motivational enhancement education program on CPAP adherence in OSA: a randomized controlled trial.

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Lai, Agnes Y K; Fong, Daniel Y T; Lam, Jamie C M; Weaver, Terri E; Ip, Mary S M

2014-09-01

Poor adherence to CPAP treatment in OSA adversely affects the effectiveness of this therapy. This randomized controlled trial (RCT) examined the efficacy of a brief motivational enhancement education program in improving adherence to CPAP treatment in subjects with OSA. Subjects with newly diagnosed OSA were recruited into this RCT. The control group received usual advice on the importance of CPAP therapy and its care. The intervention group received usual care plus a brief motivational enhancement education program directed at enhancing the subjects' knowledge, motivation, and self-efficacy to use CPAP through the use of a 25-min video, a 20-min patient-centered interview, and a 10-min telephone follow-up. Self-reported daytime sleepiness adherence-related cognitions and quality of life were assessed at 1 month and 3 months. CPAP usage data were downloaded at the completion of this 3-month study. One hundred subjects with OSA (mean ± SD, age 52 ± 10 years; Epworth Sleepiness Scales [ESS], 9 ± 5; median [interquartile range] apnea-hypopnea index, 29 [20, 53] events/h) prescribed CPAP treatment were recruited. The intervention group had better CPAP use (higher daily CPAP usage by 2 h/d [Cohen d = 1.33, P motivational enhancement education in addition to usual care were more likely to show better adherence to CPAP treatment, with greater improvements in treatment self-efficacy and daytime sleepiness. ClinicalTrials.gov; No.: NCT01173406; URL: www.clinicaltrials.gov.

Minority-carrier injection-enhanced annealing of radiation damage to InGaP solar cells

International Nuclear Information System (INIS)

Yamaguchi, M.; Okuda, T.; Taylor, S.J.

1997-01-01

The observation of minority-carrier injection-enhanced annealing of radiation-induced defects in InGaP is reported. 1-MeV electron irradiation results demonstrate superior radiation-resistance of InGa 0.5 P 0.5 solar cells compared to GaAs-on-Ge cells. Moreover, minority-carrier injection under forward bias conditions is shown to enhance defect annealing in InGaP and to result in the recovery of InGaP solar cell properties. These results suggest that the radiation-resistance of InGaP-based devices such as InGaP/GaAs(/Ge) multijunction solar cells and InGaP(As) light-emitting devices is further improved under minority-carrier injection condition. copyright 1997 American Institute of Physics

Beta Radiation Enhanced Thermionic Emission from Diamond Thin Films

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Alex Croot

2017-11-01

Full Text Available Diamond-based thermionic emission devices could provide a means to produce clean and renewable energy through direct heat-to-electrical energy conversion. Hindering progress of the technology are the thermionic output current and threshold temperature of the emitter cathode. In this report, we study the effects on thermionic emission caused by in situ exposure of the diamond cathode to beta radiation. Nitrogen-doped diamond thin films were grown by microwave plasma chemical vapor deposition on molybdenum substrates. The hydrogen-terminated nanocrystalline diamond was studied using a vacuum diode setup with a 63Ni beta radiation source-embedded anode, which produced a 2.7-fold increase in emission current compared to a 59Ni-embedded control. The emission threshold temperature was also examined to further assess the enhancement of thermionic emission, with 63Ni lowering the threshold temperature by an average of 58 ± 11 °C compared to the 59Ni control. Various mechanisms for the enhancement are discussed, with a satisfactory explanation remaining elusive. Nevertheless, one possibility is discussed involving excitation of preexisting conduction band electrons that may skew their energy distribution toward higher energies.

Enhanced antitumor efficacy of cisplatin in combination with HemoHIM in tumor-bearing mice.

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Park, Hae-Ran; Ju, Eun-Jin; Jo, Sung-Kee; Jung, Uhee; Kim, Sung-Ho; Yee, Sung-Tae

2009-03-17

Although cisplatin is one of the most effective chemotherapeutic agents, cisplatin alone does not achieve a satisfactory therapeutic outcome. Also cisplatin accumulation shows toxicity to normal tissues. In this study, we examined the possibility of HemoHIM both to enhance anticancer effect with cisplatin and to reduce the side effects of cisplatin in melanoma-bearing mice. HemoHIM was prepared by adding the ethanol-insoluble fraction to the total water extract of a mixture of 3 edible herbs, Angelica Radix, Cnidium Rhizoma and Paeonia Radix. Anticancer effects of HemoHIM with cisplatin were evaluated in melanoma-bearing mice. We used a Cr51-release assay to measure the activity of NK/Tc cell and ELISA to evaluate the production of cytokines. In melanoma-bearing mice, cisplatin (4 mg/kg B.W.) reduced the size and weight of the solid tumors, and HemoHIM supplementation with cisplatin enhanced the decrease of both the tumor size (p HemoHIM itself did not inhibit melanoma cell growth in vitro, and did not disturb the effects of cisplatin in vitro. However HemoHIM administration enhanced both NK cell and Tc cell activity in mice. Interestingly, HemoHIM increased the proportion of NK cells in the spleen. In melanoma-bearing mice treated with cisplatin, HemoHIM administration also increased the activity of NK cells and Tc cells and the IL-2 and IFN-gamma secretion from splenocytes, which seemed to contribute to the enhanced efficacy of cisplatin by HemoHIM. Also, HemoHIM reduced nephrotoxicity as seen by tubular cell of kidney destruction. HemoHIM may be a beneficial supplement during cisplatin chemotherapy for enhancing the anti-tumor efficacy and reducing the toxicity of cisplatin.

EVALUATION OF THE THERAPEUTIC EFFICACY OF HIGH-INTENSITY PULSED-PERIODIC LASER RADIATION (CLINICAL AND EXPERIMENTAL OBSERVATIONS

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V. V. Sokolov

2016-01-01

Full Text Available From the experience of clinical observations, we have shown a high therapeutic effectiveness of the medical laser KULON-MED in: cosmetics, non-cancer inflammatory diseases of the gastrointestinal tract and cancer (cancer of the stomach and colon as at different wavelengths, and with different types of photosensitizers. In the area of anti-tumor photodynamic therapy (PDT, based on experimental studies, we have showed the high antitumor (sarcoma S‑37 effectiveness of the laser (with the inhibition of tumor growth of up to 100% for repetitively pulsed irradiation mode, and for mode fractionation doses laser radiation. In addition, significant differences are shown in the effectiveness of anticancer PDT methods in the application of high-intensity lasers, continuous and pulsed caused fundamental properties of laser radiation characteristics – time structure of the radiation pulses. Thus, for the first time we have shown that the time of high-intensity laser pulses structure significantly affects therapeutic efficacy laser system, and hence on the mechanisms of interaction of laser radiation with biological tissue.

Mutants of Escherichia coli K-12 with enhanced resistance to ionizing radiation

International Nuclear Information System (INIS)

Verbenko, V.N.; Akhmedov, A.T.; Kalinin, V.L.

1986-01-01

By means of one-dimensional electrophoresis, it is shown that in radiation-resistant Gam 444 ad Gam 445 mutants of Escherichia coli K-12 high-molecular weight heat shock proteins are hyperproduced at 32-37 deg C and are induced more intensively during heat shock (in comparison to the parental) wild-tupe strain AB parallel 57). When the missense htp R15 mutation of the positive regulatory htpR gene for heat shock proteins was introduced by transduction into genome of the Gam 444 mutant, its enhanced radiation-resistance disappeared but could not be restored upon introduction of pKV3 plasmid bearing the htpR, gene. These data show that heat shock Protens are participating in the enhanced radioresistance of Gam mutants

Role of fin material and nanofluid in performance enhancement of automobile radiator

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Jadar, Raju; Shashishekar, K. S.; Channa Keshava Naik, N.

2018-04-01

An effective cooling system can avoid engine and its components from overheating and helps in achieving optimum engine performance. This work deals with the fabrication and performance evaluation of an automobile radiator with i) Aluminum fins and ii) Al-MWCNT fins using 0.1 w/v% f-MWCNT nanofluid. F-MWCNT nanoparticles in the base fluid improves the rate of heat transfer in an automobile radiator integrated with Al-MWCNT fins. The enhancement of heat transfer mainly depends on the quantity of F-MWCNT nanoparticles added to the host fluid. During the study it was found that at a low weight by volume concentration of nanofluid the heat transfer enhancement of 8% was achieved using Al-MWCNT fins compared to base fluid.

Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi.

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Dadachova, Ekaterina; Bryan, Ruth A; Huang, Xianchun; Moadel, Tiffany; Schweitzer, Andrew D; Aisen, Philip; Nosanchuk, Joshua D; Casadevall, Arturo

2007-05-23

Melanin pigments are ubiquitous in nature. Melanized microorganisms are often the dominating species in certain extreme environments, such as soils contaminated with radionuclides, suggesting that the presence of melanin is beneficial in their life cycle. We hypothesized that ionizing radiation could change the electronic properties of melanin and might enhance the growth of melanized microorganisms. Ionizing irradiation changed the electron spin resonance (ESR) signal of melanin, consistent with changes in electronic structure. Irradiated melanin manifested a 4-fold increase in its capacity to reduce NADH relative to non-irradiated melanin. HPLC analysis of melanin from fungi grown on different substrates revealed chemical complexity, dependence of melanin composition on the growth substrate and possible influence of melanin composition on its interaction with ionizing radiation. XTT/MTT assays showed increased metabolic activity of melanized C. neoformans cells relative to non-melanized cells, and exposure to ionizing radiation enhanced the electron-transfer properties of melanin in melanized cells. Melanized Wangiella dermatitidis and Cryptococcus neoformans cells exposed to ionizing radiation approximately 500 times higher than background grew significantly faster as indicated by higher CFUs, more dry weight biomass and 3-fold greater incorporation of (14)C-acetate than non-irradiated melanized cells or irradiated albino mutants. In addition, radiation enhanced the growth of melanized Cladosporium sphaerospermum cells under limited nutrients conditions. Exposure of melanin to ionizing radiation, and possibly other forms of electromagnetic radiation, changes its electronic properties. Melanized fungal cells manifested increased growth relative to non-melanized cells after exposure to ionizing radiation, raising intriguing questions about a potential role for melanin in energy capture and utilization.

Efficacy and side effects of radiation therapy in comparison with radiation therapy and temozolomide in the treatment of measurable canine malignant melanoma.

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Cancedda, S; Rohrer Bley, C; Aresu, L; Dacasto, M; Leone, V F; Pizzoni, S; Gracis, M; Marconato, L

2016-12-01

Prognosis for unresectable canine malignant melanoma (MM) is typically poor, and therapeutic approaches remain largely palliative. A bi-institutional trial was conducted to compare efficacy and safety of radiation therapy (RT) and RT with post-radiation temozolomide in dogs with chemotherapy-naïve, measurable MM. RT consisted of 5 × 6 Gy fractions over 2.5 weeks. Dogs whose owners wished to pursue chemotherapy received adjuvant oral temozolomide (60 mg m -2 for 5 days every 28 days). Fifteen dogs were treated with RT only (Group 1) and 12 dogs subsequently received temozolomide (Group 2). Overall response rate was similar between Group 1 (86.7%) and Group 2 (81.1%). Median time to progression (TTP) was significantly longer in Group 2 (205 days) compared to Group 1 (110 days; p = 0.046). Survival time was not significantly different between groups. Both treatments were well tolerated. Post-radiation temozolomide has a good safety profile, and may improve TTP in MM when compared to coarse fractionated RT. © 2014 John Wiley & Sons Ltd.

Effect of prior hyperthermia on subsequent thermal enhancement of radiation damage in mouse intestine

International Nuclear Information System (INIS)

Marigold, J.C.L.; Hume, S.P.

1982-01-01

Hyperthermia given in conjunction with X-rays results in a greater level of radiation injury than following X-rays alone, giving a thermal enhancement ratio (TER). The effect of prior hyperthermia ('priming') on TER was studied in the small intestine of mouse by giving 42.0 deg C for 1 hour at various times before the combined heat and X-ray treatments. Radiation damage was assessed by measuring crypt survival 4 days after radiation. TER was reduced when 'priming' hyperthermia was given 24-48 hours before the combined treatments. The reduction in effectiveness of the second heat treatment corresponded to a reduction in hyperthermal temperature of approximately 0.5 deg C, a value similar to that previously reported for induced resistance to heat given alone ('thermotolerance') (Hume and Marigold 1980). However, the time courses for development and decay of the TER response were much longer than those for 'thermotolerance', suggesting that different mechanisms are involved in thermal damage following heat alone and thermal enhancement of radiation damage

Quantum dots as enhancers of the efficacy of bacterial lethal photosensitization

International Nuclear Information System (INIS)

Narband, N; Parkin, I P; Mubarak, M; Nair, S P; Wilson, M; Ready, D; Green, M A; Beeby, A

2008-01-01

Because of the increasing resistance of bacteria to antibiotics there is considerable interest in light-activated antimicrobial agents (LAAAs) as alternatives to antibiotics for treating localized infections. The purpose of this study was to determine whether CdSe/ZnS quantum dots (QD) could enhance the antibacterial activity of the LAAA, toluidine blue O (TBO). Suspensions of Staphylococcus aureus and Streptococcus pyogenes were exposed to white light (3600 lux) and TBO (absorbance maximum = 630 nm) in the presence and absence of 25 nm diameter QD (emission maximum = 627 nm). When the TBO:QD ratio was 2667:1, killing of Staph. aureus was enhanced by 1.72log 10 units. In the case of Strep. pyogenes, an enhanced kill of 1.55log 10 units was achieved using TBO and QD in the ratio 267:1. Singlet oxygen and fluorescence measurements showed that QD suppress the formation of singlet oxygen from TBO and that QD fluorescence is significantly quenched in the presence of TBO (70-90%). Enhanced killing appears to be attributable to a non-Foerster resonance energy transfer mechanism, whereby the QD converts part of the incident light to the absorption maximum for TBO; hence more light energy is harvested, resulting in increased concentrations of bactericidal radicals. QD may, therefore, be useful in improving the efficacy of antimicrobial photodynamic therapy.

Nanoscale radiation transport and clinical beam modeling for gold nanoparticle dose enhanced radiotherapy (GNPT) using X-rays.

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Zygmanski, Piotr; Sajo, Erno

2016-01-01

We review radiation transport and clinical beam modelling for gold nanoparticle dose-enhanced radiotherapy using X-rays. We focus on the nanoscale radiation transport and its relation to macroscopic dosimetry for monoenergetic and clinical beams. Among other aspects, we discuss Monte Carlo and deterministic methods and their applications to predicting dose enhancement using various metrics.

Inhibition of COX-2 expression by topical diclofenac enhanced radiation sensitivity via enhancement of TRAIL in human prostate adenocarcinoma xenograft model

Science.gov (United States)

2013-01-01

Background COX-2 inhibitors have an antitumor potential and have been verified by many researchers. Treatment of cancer cells with external stressors such as irradiation can stimulate the over-expression of COX-2 and possibly confer radiation resistance. In this study, we tested if topical diclofenac, which inhibits both COX-1 and COX-2, administration rendered prostate tumor cells sensitize to the effects of radiation. Methods LNCaP-COX-2 and LNCaP-Neo cells were treated with 0 to 1000 μM diclofenac. Next, a clonogenic assay was performed in which cells were subjected to irradiation (0 to 4 Gy) with or without diclofenac. COX-2 expression and other relevant molecules were measured by real-time PCR and immunohistochemistry after irradiation and diclofenac treatment. In addition, we assessed the tumor volumes of xenograft LNCaP-COX-2 cells treated with topical diclofenac with or without radiation therapy (RT). Results LNCaP-COX-2 and LNCaP-Neo cell lines experienced cytotoxic effects of diclofenac in a dose related manner. Clonogenic assays demonstrated that LNCaP-COX-2 cells were significantly more resistant to RT than LNCaP-Neo cells. Furthermore, the addition of diclofenac sensitized LNCaP-COX-2 not but LNCaP-Neo cells to the cytocidal effects of radiation. In LNCaP-COX-2 cells, diclofenac enhanced radiation-induced apoptosis compared with RT alone. This phenomenon might be attributed to enhancement of RT-induced TRAIL expression as demonstrated by real-time PCR analysis. Lastly, tumor volumes of LNCaP-COX-2 cells xenograft treated with diclofenac or RT alone was >4-fold higher than in mice treated with combined diclofenac and radiation (pdiclofenac enhances the effect of RT on prostate cancer cells that express COX-2. Thus, diclofenac may have potential as radiosensitizer for treatment of prostate cancer. PMID:23289871

Polyfunctional monomers as additives for enhancing the radiation copolymerization of styrene with polyethylene, polypropylene, and PVC

International Nuclear Information System (INIS)

Ang, C.H.; Garnett, J.L.; Levot, R.; Long, M.A.

1982-01-01

Additives which can increase the yield in the radiation grafting of monomers to polymers are useful. The use of polyfunctional monomers as additives (approx. = 1% v/v) are shown to enhance significantly the copolymerization yields of styrene in methanol to films of polyethylene and polypropylene under certain radiation conditions. The results obtained when the polyolefins are replaced by PVC as backbone polymer in these accelerated grafting reactions are reported. Divinylbenzene (DVB) and trimethylolpropane triacrylate (TMPTA) were used as representative polyfunctional monomers for the enhancement effect. When polypropylene was used as backbone polymer, the inclusion of DVB significantly enhanced the radiation grafting of styrene in methanol at all monomer concentrations studied above 35%. At certain monomer concentrations (50% , 60%), the yield of graft copolymer was almost doubled by the addition of DVB. 3 tables. (DP)

Efficacy of enhanced external counterpulsation: our experience

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Chandra Mani Adhikari

2014-11-01

Full Text Available Aims Enhanced external counterpulsation therapy is a non-invasive, non-pharmacological outpatient treatment option for refractory angina pectoris. Our aim is to evaluate its efficacy in Nepalese refractory angina pectoris patients. Materials and methods It was single centre prospective study conducted from 2010 August to 2013 December. All thirty one (n=31 consecutive patients, referred for and received 35 hours of treatment were included in this study. The distance covered in six minute walk test before and after the treatment was recorded and compared. Patients were followed each with the questionnaires about their anginal symptoms before and after the treatment. Results In our study 19(61.3% were male and 12(38.7% female. The mean age was 65.7±9.3 years. Most patients had multi vessel disease. Twelve patients had previous history of revascularization. In 6 minute walk test there was significant difference in mean distance covered before and after the treatment. Most patients experienced decrease in the angina symptom. They had decreased in severity and frequency of angina, resulting in decreased use of sublingual nitrates. Conclusion EECP can be safe and effective treatment option for patients with RAP.

Long-term exposure to estrogen enhances chemotherapeutic efficacy potentially through epigenetic mechanism in human breast cancer cells.

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Yu-Wei Chang

Full Text Available Chemotherapy is the most common clinical option for treatment of breast cancer. However, the efficacy of chemotherapy depends on the age of breast cancer patients. Breast tissues are estrogen responsive and the levels of ovarian estrogen vary among the breast cancer patients primarily between pre- and post-menopausal age. Whether this age-dependent variation in estrogen levels influences the chemotherapeutic efficacy in breast cancer patients is not known. Therefore, the objective of this study was to evaluate the effects of natural estrogen 17 beta-estradiol (E2 on the efficacy of chemotherapeutic drugs in breast cancer cells. Estrogen responsive MCF-7 and T47D breast cancer cells were long-term exposed to 100 pg/ml estrogen, and using these cells the efficacy of chemotherapeutic drugs doxorubicin and cisplatin were determined. The result of cell viability and cell cycle analysis revealed increased sensitivities of doxorubicin and cisplatin in estrogen-exposed MCF-7 and T47D cells as compared to their respective control cells. Gene expression analysis of cell cycle, anti-apoptosis, DNA repair, and drug transporter genes further confirmed the increased efficacy of chemotherapeutic drugs in estrogen-exposed cells at molecular level. To further understand the role of epigenetic mechanism in enhanced chemotherapeutic efficacy by estrogen, cells were pre-treated with epigenetic drugs, 5-aza-2-deoxycytidine and Trichostatin A prior to doxorubicin and cisplatin treatments. The 5-aza-2 deoxycytidine pre-treatment significantly decreased the estrogen-induced efficacy of doxorubicin and cisplatin, suggesting the role of estrogen-induced hypermethylation in enhanced sensitivity of these drugs in estrogen-exposed cells. In summary, the results of this study revealed that sensitivity to chemotherapy depends on the levels of estrogen in breast cancer cells. Findings of this study will have clinical implications in selecting the chemotherapy strategies for

Sensitization to radiation and alkylating agents by inhibitors of poly(ADP-ribose) polymerase is enhanced in cells deficient in DNA double-strand break repair.

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Löser, Dana A; Shibata, Atsushi; Shibata, Akiko K; Woodbine, Lisa J; Jeggo, Penny A; Chalmers, Anthony J

2010-06-01

As single agents, chemical inhibitors of poly(ADP-ribose) polymerase (PARP) are nontoxic and have clinical efficacy against BRCA1- and BRCA2-deficient tumors. PARP inhibitors also enhance the cytotoxicity of ionizing radiation and alkylating agents but will only improve clinical outcomes if tumor sensitization exceeds effects on normal tissues. It is unclear how tumor DNA repair proficiency affects the degree of sensitization. We have previously shown that the radiosensitizing effect of PARP inhibition requires DNA replication and will therefore affect rapidly proliferating tumors more than normal tissues. Because many tumors exhibit defective DNA repair, we investigated the impact of double-strand break (DSB) repair integrity on the sensitizing effects of the PARP inhibitor olaparib. Sensitization to ionizing radiation and the alkylating agent methylmethane sulfonate was enhanced in DSB repair-deficient cells. In Artemis(-/-) and ATM(-/-) mouse embryo fibroblasts, sensitization was replication dependent and associated with defective repair of replication-associated damage. Radiosensitization of Ligase IV(-/-) mouse embryo fibroblasts was independent of DNA replication and is explained by inhibition of "alternative" end joining. After methylmethane sulfonate treatment, PARP inhibition promoted replication-independent accumulation of DSB, repair of which required Ligase IV. Our findings predict that the sensitizing effects of PARP inhibitors will be more pronounced in rapidly dividing and/or DNA repair defective tumors than normal tissues and show their potential to enhance the therapeutic ratio achieved by conventional DNA-damaging agents.

Enhancement of radiation effect on cancer cells by gold-pHLIP

Science.gov (United States)

Antosh, Michael P.; Wijesinghe, Dayanjali D.; Shrestha, Samana; Lanou, Robert; Huang, Yun Hu; Hasselbacher, Thomas; Fox, David; Neretti, Nicola; Sun, Shouheng; Katenka, Natallia; Cooper, Leon N; Andreev, Oleg A.; Reshetnyak, Yana K.

2015-01-01

Previous research has shown that gold nanoparticles can increase the effectiveness of radiation on cancer cells. Improved radiation effectiveness would allow lower radiation doses given to patients, reducing adverse effects; alternatively, it would provide more cancer killing at current radiation doses. Damage from radiation and gold nanoparticles depends in part on the Auger effect, which is very localized; thus, it is important to place the gold nanoparticles on or in the cancer cells. In this work, we use the pH-sensitive, tumor-targeting agent, pH Low-Insertion Peptide (pHLIP), to tether 1.4-nm gold nanoparticles to cancer cells. We find that the conjugation of pHLIP to gold nanoparticles increases gold uptake in cells compared with gold nanoparticles without pHLIP, with the nanoparticles distributed mostly on the cellular membranes. We further find that gold nanoparticles conjugated to pHLIP produce a statistically significant decrease in cell survival with radiation compared with cells without gold nanoparticles and cells with gold alone. In the context of our previous findings demonstrating efficient pHLIP-mediated delivery of gold nanoparticles to tumors, the obtained results serve as a foundation for further preclinical evaluation of dose enhancement. PMID:25870296

Radiation as an inducer of in-situ autologous vaccine in the treatment of solid tumors

International Nuclear Information System (INIS)

Ahmed, Mansoor M.

2013-01-01

Radiation therapy (RT) is conventionally used for local tumor control. Although local control of the primary tumor can prevent the development of subsequent systemic metastases, tumor irradiation is not effective in controlling pre-existing systemic disease. The concept of radiation-enhanced antigen presentation and immunomodulation allows the harnessing of tumor cell death induced by radiation as a potential source of tumor antigens for immunotherapy. Immunomodulation using RT is a novel strategy of in situ tumor vaccination where primary tumor irradiation can contribute to the control of pre-existing systemic metastatic disease. The absence of systemic immunosuppression (often associated with chemotherapy) and the generally lower toxicity makes radiation a desirable adjuvant regimen for immunotherapy and tumor vaccination strategies. Increased understanding of tumor immunology and the biology of radiation-mediated immune modulation should enhance the efficacy of combining these therapeutic modalities. Here we aim to provide an overview of the biology of radiation-induced immune modulation. (author)

Local dose enhancement in radiation therapy: Monte Carlo simulation study

International Nuclear Information System (INIS)

Silva, Laura E. da; Nicolucci, Patricia

2014-01-01

The development of nanotechnology has boosted the use of nanoparticles in radiation therapy in order to achieve greater therapeutic ratio between tumor and healthy tissues. Gold has been shown to be most suitable to this task due to the high biocompatibility and high atomic number, which contributes to a better in vivo distribution and for the local energy deposition. As a result, this study proposes to study, nanoparticle in the tumor cell. At a range of 11 nm from the nanoparticle surface, results have shown an absorbed dose 141 times higher for the medium with the gold nanoparticle compared to the water for an incident energy spectrum with maximum photon energy of 50 keV. It was also noted that when only scattered radiation is interacting with the gold nanoparticles, the dose was 134 times higher compared to enhanced local dose that remained significant even for scattered radiation. (author)

Blockade of the ERK pathway enhances the therapeutic efficacy of the histone deacetylase inhibitor MS-275 in human tumor xenograft models

Energy Technology Data Exchange (ETDEWEB)

Sakamoto, Toshiaki; Ozaki, Kei-ichi; Fujio, Kohsuke; Kajikawa, Shu-hei [Laboratory of Cell Regulation, Department of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521 (Japan); Uesato, Shin-ichi [Department of Biotechnology, Faculty of Engineering, Kansai University, Osaka 564-8680 (Japan); Watanabe, Kazushi [Proubase Technology Inc., Kanagawa 211-0063 (Japan); Tanimura, Susumu [Laboratory of Cell Regulation, Department of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521 (Japan); Koji, Takehiko [Department of Histology and Cell Biology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523 (Japan); Kohno, Michiaki, E-mail: kohnom@nagasaki-u.ac.jp [Laboratory of Cell Regulation, Department of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521 (Japan); Proubase Technology Inc., Kanagawa 211-0063 (Japan); Kyoto University Graduate School of Pharmaceutical Sciences, Kyoto 606-8501 (Japan)

2013-04-19

Highlights: •Blockade of the ERK pathway enhances the anticancer efficacy of HDAC inhibitors. •MEK inhibitors sensitize human tumor xenografts to HDAC inhibitor cytotoxicity. •Such the enhanced efficacy is achieved by a transient blockade of the ERK pathway. •This drug combination provides a promising therapeutic strategy for cancer patients. -- Abstract: The ERK pathway is up-regulated in various human cancers and represents a prime target for mechanism-based approaches to cancer treatment. Specific blockade of the ERK pathway alone induces mostly cytostatic rather than pro-apoptotic effects, however, resulting in a limited therapeutic efficacy of the ERK kinase (MEK) inhibitors. We previously showed that MEK inhibitors markedly enhance the ability of histone deacetylase (HDAC) inhibitors to induce apoptosis in tumor cells with constitutive ERK pathway activation in vitro. To evaluate the therapeutic efficacy of such drug combinations, we administered the MEK inhibitor PD184352 or AZD6244 together with the HDAC inhibitor MS-275 in nude mice harboring HT-29 or H1650 xenografts. Co-administration of the MEK inhibitor markedly sensitized the human xenografts to MS-275 cytotoxicity. A dose of MS-275 that alone showed only moderate cytotoxicity thus suppressed the growth of tumor xenografts almost completely as well as induced a marked reduction in tumor cellularity when administered with PD184352 or AZD6244. The combination of the two types of inhibitor also induced marked oxidative stress, which appeared to result in DNA damage and massive cell death, specifically in the tumor xenografts. The enhanced therapeutic efficacy of the drug combination was achieved by a relatively transient blockade of the ERK pathway. Administration of both MEK and HDAC inhibitors represents a promising chemotherapeutic strategy with improved safety for cancer patients.

Allopurinol, indomethacin and riboflavin enhance radiation lethality in mice

International Nuclear Information System (INIS)

Floersheim, G.L.

1994-01-01

Two widely used drugs, allopurinol and indomethacin, and the vitamin riboflavin increased the response of mice to ionizing radiation. In mice a dose of 10.5 Gy of γ rays from a 60 Co source resulted in a dose-dependent shortening of survival times after pretreatment with the three agents, applied at doses which were well tolerated alone. When the dose dependency of these drugs on the influence on survival was tested, two response patterns emerged. Indomethacin (25 mg/kg) shifted the survival curve to the left and reduced the LD 50 from ∼6.5 Gy to ∼4.5 Gy. Allopurinol (100 mg/kg) diminished the survival rate to approximately 50% irrespective of the radiation dose (ranging from 0.75 to 6.0 Gy). A similar though less striking trend was seen with riboflavin (120 mg/kg), which reduced the survival rate to approximately 65% in the dose range from 3 to 6 Gy. Mortality in mice treated with allopurinol or riboflavin and irradiated with nonlethal exposures (from radiation alone) occurred within the first few days after irradiation, suggesting a different type of injury than is usually associated with radiation death. Although doses of the three drugs used clinically are clearly lower than those providing enhanced radioresponse in our experiments, subtle and nonovert injury caused by combined exposure to the drugs and radiation cannot be completely excluded. 31 refs., 4 figs., 5 tabs

Experimental study of Gadofluorine M enhancement in early diagnosis of radiation brain injury by MRI in rats

International Nuclear Information System (INIS)

Bai Shoumin; Liao Chengde; Guo Ruomi; Huang Ying; Liang Biling; Shen Jun; Lu Taixiang

2011-01-01

Objective: To explore the value of Gadofluorine M, a novel MRI enhancement agent,in the diagnosis the early radiation brain injury. Methods: Seventy-two Wistar rats were randomly divided into 5 equal groups. To establish the radiation injury model, the rat's posterior brain was irradiated with 0 (blank controls), 25, 35, 45, 55, and 65 Gy, respectively. After irradiation MR plain scanning and Gadofluorine M enhancement scanning (after the T1WI and T2WI scanning Gf at the dosage of 0.1 mmol/kg was injected intravenously and scanning was performed again 12 h later) were performed once a week for 8 weeks. Another 12 rats were randomly divided into 2 equal groups to exposure to 55 and 65 Gy, respectively, and MR scanning was performed once a week for 8 weeks since the third week after MR. After T1WI and T2WI scanning Gd-DTPA was injected intravenously, MR was conducted again 30 min later, and Gf was injected intravenously (Gd-DTPA enhancement and Gf enhancement contrast). The MR image and the pixel count were compared. Since the third week 2 rats from the Gf enhancement scanning group and 1 rat from the Gd-DTPA enhancement and Gf enhancement contrast were killed after MR with their brains taken out to undergo pathological examination. Results: No abnormal signal changes were found in MRI in 25 and 35 Gy groups within 2 months after irradiation. A high signal in the Gf enhancement T1WI image was found in 45, 55, and 65 Gy groups within the period of 4-6 weeks after radiation. The signal intensity was significantly higher than that of the control, 25, and 35 Gy groups (F=2.15, P<0.05). The emerge time of this signal was negatively correlated with the dose of radiation (r =-0.62, P<0.05). When there was no obvious change was found by Gd-DTPA enhancement, a high signal representing change of injury could be found in Gf enhancement in the same rat. The signal intensity was significantly enhanced in Gf enhancement compared to the Gd-DTPA enhancement (F=2.74, P<0

Induction of heat shock-like proteins in Vigna sinensis seedlings growing under ultraviolet-B (280-320 nm) enhanced radiation

International Nuclear Information System (INIS)

Nedunchezhian, N.; Annamalainathan, K.; Kulandaivelu, G.

1992-01-01

The effect of ultraviolet-B (UV-B) enhanced fluorescent radiation on protein profile and protein synthesis has been investigated in Vigna sinensis L. cv. Walp seedlings growing at various temperatures. In seedlings growing at 30°C, UV-B radiation decreased the level of several proteins as seen in Coomassie brilliant blue stained gel. However, fluorography of the same gel indicates induction of three sets of proteins in the range of 70. 53 and 16 k Da. Such induction under UV-B enhanced radiation resembled that found after heat shock treatments. In seedlings at 10 and 20°C, induction of such proteins varied both qualitatively and quantitatively. At 40°C. UV-B enhanced radiation caused a cumulative effect with temperature. Strong induction of specific proteins by UV-B radiation in seedlings growing under normal temperature indicates a possible protective role

Self-efficacy enhancing intervention increases light physical activity in people with chronic obstructive pulmonary disease

Directory of Open Access Journals (Sweden)

Larson JL

2014-10-01

Full Text Available Janet L Larson,1,2 Margaret K Covey,2 Mary C Kapella,2 Charles G Alex,3,4 Edward McAuley,5 1Division of Acute, Critical and Long-Term Care Programs, School of Nursing, University of Michigan, Ann Arbor, MI, 2Department of Biobehavioral Health Science, College of Nursing, University of Illinois at Chicago, Chicago, IL, 3Division of Pulmonary and Critical Care Medicine, Edward Hines Jr VA Hospital, Hines, IL, 4Advocate Christ Medical Center, Oaklawn, IL, 5Department of Kinesiology and Community Health, College of Applied Health Sciences, University of Illinois Urbana-Champagne, Urbana, IL, USA Background: People with chronic obstructive pulmonary disease lead sedentary lives and could benefit from increasing their physical activity. The purpose of this study was to determine if an exercise-specific self-efficacy enhancing intervention could increase physical activity and functional performance when delivered in the context of 4 months of upper body resistance training with a 12-month follow-up. Methods: In this randomized controlled trial, subjects were assigned to: exercise-specific self-efficacy enhancing intervention with upper body resistance training (SE-UBR, health education with upper body resistance training (ED-UBR, or health education with gentle chair exercises (ED-Chair. Physical activity was measured with an accelerometer and functional performance was measured with the Functional Performance Inventory. Forty-nine people with moderate to severe chronic obstructive pulmonary disease completed 4 months of training and provided valid accelerometry data, and 34 also provided accelerometry data at 12 months of follow-up. The self-efficacy enhancing intervention emphasized meeting physical activity guidelines and increasing moderate-to-vigorous physical activity. Results: Differences were observed in light physical activity (LPA after 4 months of training, time by group interaction effect (P=0.045. The SE-UBR group increased time spent in

Transferrin-Modified Nanoparticles for Photodynamic Therapy Enhance the Antitumor Efficacy of Hypocrellin A

Directory of Open Access Journals (Sweden)

Xi Lin

2017-11-01

Full Text Available Photodynamic therapy (PDT has emerged as a potent novel therapeutic modality that induces cell death through light-induced activation of photosensitizer. But some photosensitizers have characteristics of poor water-solubility and non-specific tissue distribution. These characteristics become main obstacles of PDT. In this paper, we synthesized a targeting drug delivery system (TDDS to improve the water-solubility of photosensitizer and enhance the ability of targeted TFR positive tumor cells. TDDS is a transferrin-modified Poly(D,L-Lactide-co-glycolide (PLGA and carboxymethyl chitosan (CMC nanoparticle loaded with a photosensitizer hypocrellin A (HA, named TF-HA-CMC-PLGA NPs. Morphology, size distribution, Fourier transform infrared (FT-IR spectra, encapsulation efficiency, and loading capacity of TF-HA-CMC-PLGA NPs were characterized. In vitro TF-HA-CMC-PLGA NPs presented weak dark cytotoxicity and significant photo-cytotoxicity with strong reactive oxygen species (ROS generation and apoptotic cancer cell death. In vivo photodynamic antitumor efficacy of TF-HA-CMC-PLGA NPs was investigated with an A549 (TFR positive tumor-bearing model in male athymic nude mice. TF-HA-CMC-PLGA NPs caused tumor delay with a remarkable tumor inhibition rate of 63% for 15 days. Extensive cell apoptosis in tumor tissue and slight side effects in normal organs were observed. The results indicated that TDDS has great potential to enhance PDT therapeutic efficacy.

The impact of enhancing perceived self-efficacy in torture survivors.

Science.gov (United States)

Morina, Naser; Bryant, Richard A; Doolan, Emma L; Martin-Sölch, Chantal; Plichta, Michael M; Pfaltz, Monique C; Schnyder, Ulrich; Schick, Matthis; Nickerson, Angela

2018-01-01

Perceived self-efficacy (SE) is an important factor underlying psychological well-being. Refugees suffer many experiences that can compromise SE. This study tested the impact of enhancing perceived SE on coping with trauma reminders and distress tolerance in tortured refugees. Torture survivors (N = 40) were administered a positive SE induction in which they retrieved mastery-related autobiographical memories, or a non-SE (NSE) induction, and then viewed trauma-related images. Participants rated their distress following presentation of each image. Participants then completed a frustration-inducing mirror-tracing task to index distress tolerance. Participants in the SE condition reported less distress and negative affect, and improved coping in relation to viewing the trauma-related images than those in the NSE condition. The SE induction also led to greater persistence with the mirror-tracing task than the NSE induction. These findings provide initial evidence that promoting SE in tortured refugees can assist with managing distress from trauma reminders, and promoting greater distress tolerance. Enhancing perceived SE in tortured refugees may increase their capacity to tolerate distress during therapy, and may be a useful means to improve treatment response. © 2017 Wiley Periodicals, Inc.

Enhancing self-efficacy improves episodic future thinking and social-decision making in combat veterans with posttraumatic stress disorder.

Science.gov (United States)

Brown, Adam D; Kouri, Nicole A; Rahman, Nadia; Joscelyne, Amy; Bryant, Richard A; Marmar, Charles R

2016-08-30

Posttraumatic Stress Disorder (PTSD) is associated with maladaptive changes in self-identity, including impoverished perceived self-efficacy. This study examined if enhancing perceptions of self-efficacy in combat veterans with and without symptoms of PTSD promotes cognitive strategies associated with positive mental health outcomes. Prior to completing a future thinking and social problem-solving task, sixty-two OEF/OIF veterans with and without symptoms of PTSD were randomized to either a high self-efficacy (HSE) induction in which they were asked to recall three autobiographical memories demonstrating self-efficacy or a control condition in which they recalled any three autobiographical events. An interaction between HSE and PTSD revealed that individuals with symptoms of PTSD in the HSE condition generated future events with more self-efficacious statements than those with PTSD in the control condition, whereas those without PTSD did not differ in self-efficacy content across the conditions. In addition, individuals in the HSE condition exhibited better social problem solving than those in the control condition. Increasing perceptions of self-efficacy may promote future thinking and problem solving in ways that are relevant to overcoming trauma and adversity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Enhancing Cross-Cultural Training Efficacy on Expatriate Adjustment through Emotional Intelligence and Social Capital

OpenAIRE

Susanto, Ely; Rostiani, Rokhima

2012-01-01

Cross cultural training is widely believed to make a positive contribution to expatriate adjustment. In practice, however, it is very costly and sometimes ineffective for expatriates. Therefore, there is a growing importance placed on increasing the cost effectiveness or enhancing the efficacy of crosscultural training by functioning individual expatriate’s social capital and emotional intelligence as moderating variables towards expatriate’s adjustment and performance. To do so we blend idea...

Does computerized working memory training with game elements enhance motivation and training efficacy in children with ADHD?

NARCIS (Netherlands)

Prins, P.J.M.; Dovis, S.; Ponsioen, A.; ten Brink, E.; van der Oord, S.

2011-01-01

This study examined the benefits of adding game elements to standard computerized working memory (WM) training. Specifically, it examined whether game elements would enhance motivation and training performance of children with ADHD, and whether it would improve training efficacy. A total of 51

Enhancement of radiation induced oxidative stress in tumour cells by EGCG

International Nuclear Information System (INIS)

Das, U.; Das, T.; Sengupta, A.; Biswas, S.; Dey, S.; Chakraborty, A.

2017-01-01

In view of the fact that radiotherapy fails in the later stages of cancer due to the radioresistant tumor cells, it is most important in radiobiology to enhance the oxidative damage of the tumor cells by using a tumor selective cytotoxic agent. The increase in radiosensitivity is important both for optimizing radiation dose for tumors and for designing strategies to improve the therapeutic ratio. Amount and time of treatment of radiation (IR), epigallocatechin gallate (EGCG) and epicatechin (EC) were determined using MTT assay. Biochemical assay, Flow cytometry and immune blots were employed to elucidate the enhanced sensitization of EC and EGCG along with IR in hepatocellular carcinoma cells (HepG2). The effects were more effective in killing the HepG2 cells compared to only irradiation. It was observed that the ROS generation was significantly increased in combination group (IR+EGCG/EC) over the IR group. Lower reduced glutathione content, higher TBARS and decreased catalase activity in combination group provided additive support. Combination treatment caused cell cycle arrest at G2/M phase. Mitochondrial membrane potential was greatly reduced and the percentage of apoptotic population increased in combination group compared to IR alone. Moreover, the higher expression of p53 and activation of caspase 3 in combination group over the IR alone indicated EC and EGCG along with ionizing radiation increase the oxidative stressed condition in HepG2 cell that leads the apoptosis of the cells. The novel use of this combination of radiation and tea polyphenol will remain an effective radiotherapeutic strategy. (author)

Radiation-enhanced thermal processes during implantation of gold into copper

Energy Technology Data Exchange (ETDEWEB)

Perret, N.E.; King, B.V.; Dastoor, P.C. [Newcastle Univ., NSW (Australia). Dept. of Physics

1996-12-31

A copper (100) single crystal has been implanted with gold ions at temperatures ranging from 133 K to 673 K. Rutherford Backscattering Spectroscopy (RBS) has been used to observe the changes in the gold implant distribution that occur as a function of the sample temperature during implantation. Two distinct effects have been observed. Firstly the gold implant distribution, as a function of depth, broadens with sample temperature. This broadening of the gold depth profile is most marked at temperatures above 473 K. Secondly, the gold is implanted deeper into the copper crystal as the sample temperature is increased. These results are discussed in terms of radiation enhanced diffusion and radiation-induced segregation processes. 10 refs., 3 figs.

Radiation-enhanced thermal processes during implantation of gold into copper

Energy Technology Data Exchange (ETDEWEB)

Perret, N E; King, B V; Dastoor, P C [Newcastle Univ., NSW (Australia). Dept. of Physics

1997-12-31

A copper (100) single crystal has been implanted with gold ions at temperatures ranging from 133 K to 673 K. Rutherford Backscattering Spectroscopy (RBS) has been used to observe the changes in the gold implant distribution that occur as a function of the sample temperature during implantation. Two distinct effects have been observed. Firstly the gold implant distribution, as a function of depth, broadens with sample temperature. This broadening of the gold depth profile is most marked at temperatures above 473 K. Secondly, the gold is implanted deeper into the copper crystal as the sample temperature is increased. These results are discussed in terms of radiation enhanced diffusion and radiation-induced segregation processes. 10 refs., 3 figs.

Radiation-enhanced thermal processes during implantation of gold into copper

International Nuclear Information System (INIS)

Perret, N.E.; King, B.V.; Dastoor, P.C.

1996-01-01

A copper (100) single crystal has been implanted with gold ions at temperatures ranging from 133 K to 673 K. Rutherford Backscattering Spectroscopy (RBS) has been used to observe the changes in the gold implant distribution that occur as a function of the sample temperature during implantation. Two distinct effects have been observed. Firstly the gold implant distribution, as a function of depth, broadens with sample temperature. This broadening of the gold depth profile is most marked at temperatures above 473 K. Secondly, the gold is implanted deeper into the copper crystal as the sample temperature is increased. These results are discussed in terms of radiation enhanced diffusion and radiation-induced segregation processes. 10 refs., 3 figs

Biological research for the radiation protection

International Nuclear Information System (INIS)

Kim, In Gyu; Kim, Chan Kug; Shim, Hae Won; Jung, Il Lae; Byun, Hee Sun; Moon, Myung Sook; Cho, Hye Jeong; Kim, Jin Sik

2003-04-01

The work scope of 'Biological Research for the Radiation Protection' had contained the research about polyamine effect on cell death triggered ionizing radiation, H 2 O 2 and toxic agents. In this paper, to elucidate the role of polyamines as mediator in lysosomal damage and stress(H 2 O 2 )- induced apoptosis, we utilized α-DiFluoroMethylOrnithine (DFMO), which inhibited ornithine decarboxylase and depleted intracellular putrescine, and investigated the effects of polyamine on the apoptosis caused by H 2 O 2 , ionizing radiation and paraquat. We also showed that MGBG, inhibitor of polyamine biosynthesis, treatment affected intracellular redox steady states, intracellular ROS levels and protein oxidation. Thereafter we also investigated whether MGBG may enhance the cytotoxic efficacy of tumor cells caused by ionizing radiation or H 2 O 2 because such compounds are able to potentiate the cell-killing effects. In addition, ceruloplasmin and thioredoxin, possible antioxidant proteins, were shown to have protective effect on radiation- or H 2 O 2 (or chemicals)-induced macromolecular damage or cell death

Enhancement of Radiation Response in Osteosarcoma and Rhabomyosarcoma Cell Lines by Histone Deacetylase Inhibition

International Nuclear Information System (INIS)

Blattmann, Claudia; Oertel, Susanne; Ehemann, Volker

2010-01-01

Purpose: Histone deacetylase inhibitors (HDACIs) can enhance the sensitivity of cells to photon radiation treatment (XRT) by altering numerous molecular pathways. We investigated the effect of pan-HDACIs such as suberoylanilide hydroxamic acid (SAHA) on radiation response in two osteosarcoma (OS) and two rhabdomyosarcoma (RMS) cell lines. Methods and Materials: Clonogenic survival, cell cycle analysis, and apoptosis were examined in OS (KHOS-24OS, SAOS2) and RMS (A-204, RD) cell lines treated with HDACI and HDACI plus XRT, respectively. Protein expression was investigated via immunoblot analysis, and cell cycle analysis and measurement of apoptosis were performed using flow cytometry. Results: SAHA induced an inhibition of cell proliferation and clonogenic survival in OS and RMS cell lines and led to a significant radiosensitization of all tumor cell lines. Other HDACI such as M344 and valproate showed similar effects as investigated in one OS cell line. Furthermore, SAHA significantly increased radiation-induced apoptosis in the OS cell lines, whereas in the RMS cell lines radiation-induced apoptosis was insignificant with and without SAHA. In all investigated sarcoma cell lines, SAHA attenuated radiation-induced DNA repair protein expression (Rad51, Ku80). Conclusion: Our results show that HDACIs enhance radiation action in OS and RMS cell lines. Inhibition of DNA repair, as well as increased apoptosis induction after exposure to HDACIs, can be mechanisms of radiosensitization by HDACIs.

Enhanced radiation tolerance of ultrafine grained Fe–Cr–Ni alloy

International Nuclear Information System (INIS)

Sun, C.; Yu, K.Y.; Lee, J.H.; Liu, Y.; Wang, H.; Shao, L.; Maloy, S.A.; Hartwig, K.T.; Zhang, X.

2012-01-01

Highlights: ► Ultrafine grained Fe-Cr-Ni alloy was processed by equal channel angular pressing technique. ► The overall Helium bubble density and dislocation loop density were reduced by grain refinement. ► The ultrafine grained microstructure alleviated radiation-induced hardening. - Abstract: The evolutions of microstructure and mechanical properties of Fe–14Cr–16Ni (wt.%) alloy subjected to Helium ion irradiations were investigated. Equal channel angular pressing (ECAP) process was used to significantly reduce the average grain size from 700 μm to 400 nm. At a peak fluence level of 5.5 displacement per atom (dpa), helium bubbles, 0.5–2 nm in diameter, were observed in both coarse-grained (CG) and ultrafine grained (UFG) alloy. The density of He bubbles, dislocation loops, as well as radiation hardening were reduced in the UFG Fe–Cr–Ni alloy comparing to those in its CG counterpart. The results imply that radiation tolerance in bulk metals can be effectively enhanced by refinement of microstructures.

Enhanced tumor responses through therapies combining CCNU, MISO and radiation

International Nuclear Information System (INIS)

Siemann, D.W.; Hill, S.A.

1984-01-01

Studies were performed to determine whether the radiation sensitizer misonidazole (MISO) could enhance the tumor control probability in a treatment strategy combining radiation and the nitrosourea 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU). In initial experiments KHT sarcoma-bearing mice were injected with 1.0 mg/g of MISO simultaneously with a 20 mg/kg dose of CCNU 30-40 min prior to irradiation (1500 rad). With this treatment protocol approximately 60% of the mice were found to be tumor-free 100 days post treatment. By comparison all 2 agent combinations led to 0% cures. To evaluate the relative importance of chemopotentiation versus radiosensitization in the 3 agent protocol, tumors were treated with MISO plus one anti-tumor agent (either radiation of CCNU) and then at times ranging from 0 to 24 hr later exposed to the other agent. When the time between treatments was 0 to 6 hr, a 60 to 80% tumor control rate was achieved for both MISO plus radiation followed by CCNU and MISO plus CCNU followed by radiation. However if the time interval was increased to 18 or 24 hr, the cure rate in the former treatment regimen dropped to 10% while that of the latter remained high at 40%. The data therefore indicate that (1) improved tumor responses may be achieved when MISO is added to a radiation-chemotherapy combination and (2) MISO may be more effective in such a protocol when utilized as a chemopotentiator

Communicative social capital and collective efficacy as determinants of access to health-enhancing resources in residential communities.

Science.gov (United States)

Matsaganis, Matthew D; Wilkin, Holley A

2015-04-01

This article contributes to the burgeoning literature on the social determinants of health disparities. The authors investigate how communication resources and collective efficacy, independently and in combination, shape residents' access to health enhancing resources (including healthcare services, sources of healthier food options, and public recreation spaces) in their communities. Using random digit dial telephone survey data from 833 residents of South Los Angeles communities the authors show that communicative social capital-that is, an information and problem-solving resource that accrues to residents as they become more integrated into their local communication network of neighbors, community organizations, and local media-plays a significant role in access to health resources. This relationship is complicated by individuals' health insurance and health status, as communicative social capital magnifies the sense of absence of resources for those who are in worse health and lack insurance. Communicative social capital builds collective efficacy, which is positively related to access to health-enhancing resources, but it also mediates the negative relationship between communicative social capital and access to health resources. Residents with richer stores of communicative social capital and collective efficacy report better access to health resources. The authors conclude with a discussion of implications of these findings and suggestions for future research.

Modification of Biomolecules and Combined Actions by Radiation

International Nuclear Information System (INIS)

Kim, Jin Kyu

2014-01-01

KAERI, ARTI has been doing a pivotal role for research and development in radiation technologies. Strong motivation and RT-based biotechnologies necessary for the future R and D plans can be provided form the results of this research. An advanced analytical method was suggested for the combined action of ionizing radiation with another factor. Using the method, it is possible to predict in advance the maximum value of synergistic interaction and the conditions to achieve the maximum. The results of this study give a clues for establishment of important technology associated with enhancing positive efficacy of radiation applications. By elaborating the present research results, new technologies will be established for analysing the combined effects of radiation with another factor and radiosensitivity of organisms. In the long run, de novo biodosimetry techniques will be developed and it can play an important role for ARTI to be an internationally recognized radiation biology and biodosimetry laboratory

Efficacy of ultraviolet radiation as an alternative technology to inactivate microorganisms in grape juices and wines.

Science.gov (United States)

Fredericks, Ilse N; du Toit, Maret; Krügel, Maricel

2011-05-01

Since sulphur dioxide (SO(2)) is associated with health risks, the wine industry endeavours to reduce SO(2) levels in wines with new innovative techniques. The aim of this study was, therefore, to investigate the efficacy of ultraviolet radiation (UV)-C (254 nm) as an alternative technology to inactivate microorganisms in grape juices and wines. A pilot-scale UV-C technology (SurePure, South Africa) consisting of an UV-C germicidal lamp (100 W output; 30 W UV-C output) was used to apply UV-C dosages ranging from 0 to 3672 J l(-1), at a constant flow rate of 4000 l h(-1) (Re > 7500). Yeasts, lactic and acetic acid bacteria were singly and co-inoculated into 20 l batches of Chenin blanc juice, Shiraz juice, Chardonnay wine and Pinotage wine, respectively. A dosage of 3672 J l(-1), resulted in an average log(10) microbial reduction of 4.97 and 4.89 in Chardonnay and Pinotage, respectively. In Chenin blanc and Shiraz juice, an average log(10) reduction of 4.48 and 4.25 was obtained, respectively. UV-C efficacy may be influenced by liquid properties such as colour and turbidity. These results had clearly indicated significant (p radiation may stabilize grape juice and wine microbiologically in conjunction with reduced SO(2) levels. Copyright © 2010 Elsevier Ltd. All rights reserved.

AGuIX, a theranostic nano-particle to improve image-guided radiation therapy: a proof of concept in pancreatic cancer

International Nuclear Information System (INIS)

Detappe, Alexandre

2017-01-01

Previous studies demonstrated AGuIX ability to act as an efficient radiosensitizer under the presence of preclinical radiations or monoenergetic radiation beams for multiple cancer models. The preclinical irradiation (220 kV) has been shown effective in activating high atomic number (Z) nanoparticles. The energy peak is close to the k-edge of the different high-Z elements used (50.2 keV for the gadolinium), leading to a strong photoelectric effect. Auger electrons generation and biological effects occur afterwards creating a local dose enhancement. However, clinical treatments use a higher energy beam (≥6 MV). At these energy ranges, the photoelectric probability is less important, decreasing the direct interaction of the nanoparticles with the incoming photons. We performed a proof of concept on a pancreatic tumor model, known for its low survival rates, with preclinical and clinical radiation beams to evaluate the efficacy of the AGuIX. To increase the efficacy of the clinical radiation beam without modifying the nanoparticle structure in order to obtain a dose enhancement close to the one observed with the preclinical beam, we evaluated key clinical beam parameters to understand and increase the mechanisms of interaction between the incident photons and the high-Z nanoparticles. Hence, we evaluated analytically the impact of the radiation beam under different conditions of irradiation, confirming the potential of the AGuIX with a preclinical beam, and finally shown their significant efficacy under a clinical setup. This study is the first to evaluate the potential of a high-Z nanoparticle to act as radiosensitizer following low dose intravenous injections. (author)

Radiation-enhanced diffusion in nickel-10.6% chromium alloys

International Nuclear Information System (INIS)

Gieb, M.

1995-01-01

Results of investigations of the diffusion rate of nickel-10.6% chromium alloys after plastic deformation, after quenching from 700 C and from 1030 C, and during irradiation with 18 MeV protons and 1.85 MeV electrons are reported. The diffusion rate is measured by means of the electrical resistivity which increases with increasing degree of short range order. It was found that the characteristic temperature below which short range order develops is T t =550 C. Below about 400 C the atomic mobilities of the component atoms of the alloy are so small that no further increase in the degree of short range order is found in due laboratory times. The activation energy for self-diffusion was determined after quenching from 700 C to Q SD =2.88 eV. For the migration activation energy of vacancies a value of E M 1V =1.18 eV was obtained after quenching from 1030 C. For the migration activation energies of interstitials and vacancies values of E M 1I =1.04 eV and E M 1V =1.16 eV are derived from results of measurements of radiation enhanced diffusion, respectively. These values decrease with increasing high energy particle flux. The characteristic temperature for interstitial cluster formation is T t =300 C. Above this temperature radiation-induced interstitials and vacancies annihilate mainly by pair recombination. Below this temperature interstitials also annihilate at sinks which are formed during irradiation so that the concentration of vacancies increases with irradiation time. Their migration activation energy is approximately obtained in a straight-forward way from the experimental data. Above about 380 C the radiation enhanced diffusion rate is surprisingly much smaller than the thermal diffusion rate. The quasi-dynamic vacancy concentration built up during irradiation is much smaller than the thermal vacancy concentration. (orig.)

Impurity enrichment and radiative enhancement using induced SOL flow in DIII-D

International Nuclear Information System (INIS)

Wade, M.R.; West, W.P.; Wood, R.D.

1998-07-01

Experiments on DIII-D have demonstrated the efficacy of using induced scrap-off-layer (SOL) flow to preferentially enrich impurities in the divertor plasma. This SOL floe is produced through simultaneous deuterium gas injection at the midplane and divertor exhaust. Using this SOL flow, an improvement in enrichment (defined as the ratio of impurity fraction in the divertor to that in the plasma core) has been observed for all impurities in trace-level experiments (i.e., impurity level is non-perturbative), with the degree of improvement increasing with impurity atomic number. In the case of argon, exhaust gas enrichment using modest SOL flow is as high as 17. Using this induced SOL flow technique and argon injection, radiative plasmas have been produced that combine high radiation losses (P rad /P input > 70%), low core fuel dilution (Z eff E > 1.0 τ E,ITER93H )

Differentiation of recurrent breast cancer from radiation fibrosis with dynamic gadolinium-enhanced MR imaging

International Nuclear Information System (INIS)

Dao, T.H.; Campana, F.; Fourquet, A.; Rahmouni, A.

1991-01-01

This paper assesses the ability of dynamic gadolinium-enhanced MR imaging to differentiate radiation fibrosis from tumor recurrence of breast cancer after conservative treatment. Twenty-five women with previous breast cancer treated with radiation therapy underwent MR imaging examination. Tumor recurrence was suspected on palpation of masses (18 cases) or at mammography (7 cases). The MR imaging protocol was performed on a 0.5-T imager with a breast coil and included T1 and T2 spin-echo, short To inversion recovery (STIR), and dynamic gadolinium-enhanced T1-weighted sequenced to evaluate the hemokinetics of the lesion. Ratios of signal intensity of suspected lesions to that of fat, surrounding breast gland, and background noise were calculated. Percutaneous biopsies were performed in all cases after MR imaging. Curves of signal-to-noise ratio of recurrences (5 cases) showed an early enhancement within the first minutes after injection, although localized fibrosis (20 cases) was not significantly enhanced. T2 and STIR sequences were not contributive in differentiating fibrosis from tumor recurrence

Clinical trial experience using erythropoietin during radiation therapy

International Nuclear Information System (INIS)

Lavey, R.S.

1998-01-01

Oncologists have several reasons for trying to maintain or increase hemoglobin levels in their patients during therapy. Relief of the symptoms of anemia, including fatigue and dyspnea, are traditional, well-accepted indications. A newer rationale is to enhance the efficacy of radiation therapy and/or chemotherapy in controlling tumors. A laboratory animal study found that administration of recombinant human erythropoietin (rHuEPO) increased intratumoral median oxygen levels and diminished the proportion of measurements in the very low ( [de

Radiation exposure and radiation protection

International Nuclear Information System (INIS)

Heuck, F.; Scherer, E.

1985-01-01

The present volume is devoted to the radiation hazards and the protective measures which can be taken. It describes the current state of knowledge on the changes which exposure to ionizing rays and other forms of physical energy can induce in organs and tissues, in the functional units and systems of the organism. Special attention is paid to general cellular radiation biology and radiation pathology and to general questions of the biological effects of densely ionizing particle radiation, in order to achieve a better all-round understanding of the effects of radiation on the living organism. Aside from the overviews dealing with the effects of radiation on the abdominal organs, urinary tract, lungs, cerebral and nervous tissue, bones, and skin, the discussion continues with the lymphatic system, the bone marrow as a bloodforming organ, and the various phases of reaction in the reproductive organs, including damage and subsequent regeneration. A special section deals with environmental radiation hazards, including exposure to natural radiation and the dangers of working with radioactive substances, and examines radiation catastrophes from the medical point of view. Not only reactor accidents are covered, but also nuclear explosions, with exhaustive discussion of possible damage and treatment. The state of knowledge on chemical protection against radiation is reviewed in detail. Finally, there is thorough treatment of the mechanism of the substances used for protection against radiation damage in man and of experience concerning this subject to date. In the final section of the book the problems of combined radiotherapy are discussed. The improvement in the efficacy of tumor radiotherapy by means of heavy particles is elucidated, and the significance of the efficacy of tumor therapy using electron-affinitive substances is explained. There is also discussion of the simultaneous use of radiation and pharmaceuticals in the treatment of tumors. (orig./MG) [de

Chemical modifications of antisense morpholino oligomers enhance their efficacy against Ebola virus infection.

Science.gov (United States)

Swenson, Dana L; Warfield, Kelly L; Warren, Travis K; Lovejoy, Candace; Hassinger, Jed N; Ruthel, Gordon; Blouch, Robert E; Moulton, Hong M; Weller, Dwight D; Iversen, Patrick L; Bavari, Sina

2009-05-01

Phosphorodiamidate morpholino oligomers (PMOs) are uncharged nucleic acid-like molecules designed to inactivate the expression of specific genes via the antisense-based steric hindrance of mRNA translation. PMOs have been successful at knocking out viral gene expression and replication in the case of acute viral infections in animal models and have been well tolerated in human clinical trials. We propose that antisense PMOs represent a promising class of therapeutic agents that may be useful for combating filoviral infections. We have previously shown that mice treated with a PMO whose sequence is complementary to a region spanning the start codon of VP24 mRNA were protected against lethal Ebola virus challenge. In the present study, we report on the abilities of two additional VP24-specific PMOs to reduce the cell-free translation of a VP24 reporter, to inhibit the in vitro replication of Ebola virus, and to protect mice against lethal challenge when the PMOs are delivered prior to infection. Additionally, structure-activity relationship evaluations were conducted to assess the enhancement of antiviral efficacy associated with PMO chemical modifications that included conjugation with peptides of various lengths and compositions, positioning of conjugated peptides to either the 5' or the 3' terminus, and the conferring of charge modifications by the addition of piperazine moieties. Conjugation with arginine-rich peptides greatly enhanced the antiviral efficacy of VP24-specific PMOs in infected cells and mice during lethal Ebola virus challenge.

8-aminoadenosine enhances radiation-induced cell death in human lung carcinoma A549 cells

International Nuclear Information System (INIS)

Meike, Shunsuke; Yamamori, Tohru; Yasui, Hironobu; Eitaki, Masato; Inanami, Osamu; Matsuda, Akira

2011-01-01

The combination of a chemotherapeutic agent and radiation is widely applied to enhance cell death in solid tumor cells in cancer treatment. The purine analogue 8-aminoadenosine (8-NH 2 -Ado) is known to be a transcription inhibitor that has proved very effective in multiple myeloma cell lines and primary indolent leukemia cells. In this report, to examine whether 8-NH 2 -Ado had the ability to enhance the radiation-induced cell killing in solid tumor cells, human lung adenocarcinoma A549 cells were irradiated in the presence and absence of 8-NH 2 -Ado. 8-NH 2 -Ado significantly increased reproductive cell death and apoptosis in A549 cells exposed to X-rays. When peptide inhibitors against caspase-3, -8, and -9 were utilized to evaluate the involvement of caspases, all inhibitors suppressed the enhancement of radiation-induced apoptosis, suggesting that not only mitochondria-mediated apoptotic signal transduction pathways but also death receptor-mediated pathways were involved in this enhancement of apoptosis. In addition, in the cells exposed to the treatment combining X-irradiation and 8-NH 2 -Ado, reduction of the intracellular ATP concentration was essential for survival, and down-regulation of the expression of antiapoptotic proteins such as survivin and X-linked inhibitor of apoptosis protein (XIAP) was observed. These results indicate that 8-NH 2 -Ado has potential not only as an anti-tumor drug for leukemia and lymphoma but also as a radiosensitizing agent for solid tumors. (author)

Radiation enhancement effect of RNA interference for HIF-1α on the transplant tumor

International Nuclear Information System (INIS)

Ren Ruimei; Sun Xindong; Zhao Hanxi; Yan Qingxia; Huang Guangwu

2008-01-01

Objective: To determine and explore the radiation enhancement of RNA interference for HIF-1α on the transplant tumor using polycationic polyethylenimine (PEI), as a new kind of gene vector. Methods: SPCA-1 nude mouse model was used. 160 nude mice bearing SPCA-1 were randomly divided into 4 treated groups and 1 control groups, each group had 32 mice. The expression of HIF-1α was studied by immunohistochemical method after RNA interference for HIF-1α. The differences of the volume, weight, survival time of the transplant tumor were studied among the simple radiation group, the simple RNA interference for HIF- 1α group and the combination of radiation and RNA interference for HIF-1α. Results: The expression of HIF-1α was decreased after RNA interference for HIF-1α. RNA interference for HIF-1α combined with radiation decreased the volume, weight of the transplant tumor, and prolonged its survival time period significantly than other methods. Conclusions: RNA interference targeting HIF-1α might enhance the radiosensitivity of the transplant tumor using PEI as a new kind of gene vector in vitro. (authors)

Efficacy of Information and Communication Technology in Enhancing Learning Outcomes of Students with Hearing Impairment in Ibadan

Science.gov (United States)

Egaga, Patrick I.; Aderibigbe, S. Akinwumi

2015-01-01

The study aimed at examining the efficacy of Information and Communication Technology (ICT) in enhancing learning outcomes of students with hearing impairment in Ibadan. The study adopted a pretest, post-test, control group quasi-experimental research design. Purposive sampling techniques was used for the selection of thirty participants…

rCBF in radiation necrosis as measured by xenon-enhanced CT

International Nuclear Information System (INIS)

Nakamura, Osamu; Nomura, Kazuhiro; Segawa, Hiromu; Nakagomi, Tadayoshi; Tanaka, Hideki; Yoshimasu, Norio; Takakura, Kintomo.

1986-01-01

We experienced a case of radiation necrosis in which the necrosis occurred two and a half years after radiation therapy against craniopharyngioma. In this case, we evaluated the regional cerebral blood flow (rCBF) by means of the Xe-enhanced CT method and studied the change in rCBF in comparison with the rCBF pattern of brain tumors or cerebral infarctions. In general, rCBF decreased in accordance with the low-density area in a conventional CT scan. The decrease in rCBF was most significant in the white matter, but the rCBF in the thinned cortex was also lowered. On the contrary, that of the basal ganglia was almost completely preserved. The rCBF pattern was different from those of brain tumors or diffuse cerebral infarction caused by the occlusion of the main arteries and was thought to be characteristic of radiation necrosis. Differential diagnosis between radiation necrosis and the recurrence of brain tumor has been thought to be difficult, but with this rCBF analysis the possibility of differential diagnosis between the two lesions was clearly indicated. (author)

Large enhancement of radiative strength for soft transitions in the quasicontinuum.

Science.gov (United States)

Voinov, A; Algin, E; Agvaanluvsan, U; Belgya, T; Chankova, R; Guttormsen, M; Mitchell, G E; Rekstad, J; Schiller, A; Siem, S

2004-10-01

Radiative strength functions (RSFs) for the (56,57)Fe nuclei below the separation energy are obtained from the 57Fe(3He,alphagamma)56Fe and 57Fe(3He,3He'gamma)57Fe reactions, respectively. An enhancement of more than a factor of 10 over common theoretical models of the soft (E(gamma) less than or approximately equal 2 MeV) RSF for transitions in the quasicontinuum (several MeV above the yrast line) is observed. Two-step cascade intensities with soft primary transitions from the 56Fe(n,2gamma)57Fe reaction confirm the enhancement.

Efficacy of RADPAD® protection drape in reducing radiation exposure to the primary operator during Transcatheter Aortic Valve Implantation (TAVI).

Science.gov (United States)

Sharma, Divyesh; Ramsewak, Adesh; Manoharan, Ganesh; Spence, Mark S

2016-02-01

The efficacy of RADPAD® (a sterile, lead-free drape) has been demonstrated to reduce the scatter radiation to the primary operator during fluoroscopic procedures. However, the use of the RADPAD® during TAVI procedures has not been studied. Transcatheter aortic valve implantation (TAVI) is now an established treatment for patients with symptomatic severe aortic stenosis who are deemed inoperable or at high risk for conventional surgical aortic valve replacement (AVR). Consequently the radiation exposure to the patient and the interventional team from this procedure has become a matter of interest and importance. Methods to reduce radiation exposure to the interventional team during this procedure should be actively investigated. In this single center prospective study, we determined the radiation dose during this procedure and the efficacy of RADPAD® in reducing the radiation dose to the primary operator. Fifty consecutive patients due to undergo elective TAVI procedures were identified. Patients were randomly assigned to undergo the procedure with or without the use of a RADPAD® drape. There were 25 patients in each group and dosimetry was performed at the left eye level of the primary operator. The dosimeter was commenced at the start of the procedure, and the dose was recorded immediately after the end of the procedure. Fluoroscopy times and DAP were also recorded prospectively. Twenty-five patients underwent transfemoral TAVI using a RADPAD® and 25 with no-RADPAD®. The mean primary operator radiation dose was significantly lower in the RADPAD group at 14.8 mSv vs. 24.3 mSv in the no-RADPAD group (P=0.008). There was no significant difference in fluoroscopy times or dose-area products between the two patient groups. The dose to the primary operator relative to fluoroscopy time (RADPAD: slope=0.325; no RADPAD: slope=1.148; analysis of covariance F=7.47, P=0.009) and dose area product (RADPAD: slope=0.0007; no RADPAD: slope=0.002; analysis of covariance F=7

Enhancement of efficacy of process water monitors in detecting heavy water leak in steam generator blow down lines

International Nuclear Information System (INIS)

Mitra, S.R.; Kohale, S.D.; Parida, B.K.; Gathe, G.D.; Pati, C.K.; Mudgal, B.K.; Niraj; Pawar, S.K.

2006-01-01

The Steam Generator (SG) serves as an interface between primary and secondary cycle in Pressurized Heavy Water Reactor (PHWR). Failure of steam generator tubes result in leaking of active heavy water in the secondary closed loop. In Tarapur Atomic Power Station-3 and 4 (TAPS- 3 and 4), Scintillator detectors are provided to detect on line heavy water leakages in SG and moderator heat exchangers by monitoring Nitrogen-16 ( 16 N) and Oxygen-19 ( 19 O) activities. Efficacy of detection of these activities at designed detector position on SG blow down line in presence of background radiation field is analysed theoretically. The count rate of 19 O and 16 N estimated at the detector position inside Reactor Building (RB) shows that detectors only respond to very high leak rates due to presence of high ambient radiation level even though sensitivity is appreciably good. For detector position in RB in the accessible areas and out side the RE containment, the travel time for the blow down feed water becomes moderately and very long respectively resulting in poor sensitivity. However the results show that wherever background levels is low, the efficacy of leak detection becomes considerably better than the results obtained when detector is placed inside RB. The study was validated during the reactor operation by recording the detector count rates due to prevalent ambient radiation level near to the detectors. Subsequently the detectors were relocated in an area inside RB where relocation was feasible, travel time of the blow down feed water was moderate and the area had an relatively low ambient radiation level. This paper discusses the methodology adopted during the study and results obtained during theoretical estimation and practical validation. (author)

Heat transfer enhancement of car radiator using aqua based magnesium oxide nanofluids

Directory of Open Access Journals (Sweden)

Ali Hafiz Muhammad

2015-01-01

Full Text Available The focus of this research paper is on the application of water based MgO nanofluids for thermal management of a car radiator. Nanofluids of different volumetric concentrations (i.e. 0.06%, 0.09% and 0.12% were prepared and then experimentally tested for their heat transfer performance in a car radiator. All concentrations showed enhancement in heat transfer compared to the pure base fluid. A peak heat transfer enhancement of 31% was obtained at 0.12 % volumetric concentration of MgO in basefluid. The fluid flow rate was kept in a range of 8-16 liter per minute. Lower flow rates resulted in greater heat transfer rates as compared to heat transfer rates at higher flow rates for the same volumetric concentration. Heat transfer rates were found weakly dependent on the inlet fluid temperature. An increase of 8°C in inlet temperature showed only a 6% increase in heat transfer rate.

Molecular image guided radiation therapy-MIGRT in radiobioluminescence and nanoradioguidance

International Nuclear Information System (INIS)

Rao, V.L. Papineni

2014-01-01

Accurate dose delivery to malignant tissue in radiotherapy is essential for enhancing the treatment efficacy while minimizing morbidity of surrounding normal tissues. Advances in therapeutic strategies and diagnosis technologies along with our understanding of the biology of tumor response to radiation therapy have paved way to allow nearly 60% of current cancer patients to be treated with Radiation Therapy. The confluence of molecular imaging and nanotechnology fields are bridging physics and medicine and are quickly making strides in opening new avenues and therapeutic strategies that complement radiation therapy - with a distinct footprint in immunotherapy, adoptive cell therapy, and targeted chemotherapy. Incorporating optical imaging in radiation therapy in my laboratory, endogenous bioluminescence resulting from whole body irradiation in different organs, and in different animals, which is distinct from the Cherenkov radiation. The endogenous bioluminescence in response to irradiation is coined recently as radiobioluminescence. Thus with the necessity, the design, construction, and validation of Molecular Image Guided Radiation Therapy (MIGRT) instrumentation for preclinical theragnostics is carried out

He-Ne laser treatment improves the photosynthetic efficiency of wheat exposed to enhanced UV-B radiation

International Nuclear Information System (INIS)

Chen, Huize; Han, Rong

2014-01-01

The level of ultraviolet-B (UV-B) radiation on the Earth’s surface has increased due to depletion of the ozone layer. Here, we explored the effects of continuous wave He-Ne laser irradiation (632 nm, 5 mW mm –2 , 2 min d –1 ) on the physiological indexes of wheat seedlings exposed to enhanced UV-B radiation (10 KJ m –2 d –1 ) at the early growth stages. Wheat seedlings were irradiated with enhanced UV-B, He-Ne laser treatment or a combination of the two. Enhanced UV-B radiation had deleterious effects on wheat photosynthesis parameters including photosystem II (chlorophyll content, Hill reaction, chlorophyll fluorescence parameters, electron transport rate (ETR), and yield), the thylakoid (optical absorption ability, cyclic photophosphorylation, Mg 2+ -ATPase, and Ca 2+ -ATPase) and some enzymes in the dark reaction (phosphoenolpyruvate carboxylase (PEPC), carbonic anhydrase (CA), malic dehydrogenase (MDH), and chlorophyllase). These parameters were improved in UV-B-exposed wheat treated with He-Ne laser irradiation; the parameters were near control levels and the enzyme activities increased, suggesting that He-Ne laser treatment partially alleviates the injury caused by enhanced UV-B irradiation. Furthermore, the use of He-Ne laser alone had a favourable effect on seedling photosynthesis compared with the control. Therefore, He-Ne laser irradiation can enhance the adaptation capacity of crops. (paper)

Response assessment of stereotactic body radiation therapy using dynamic contrast-enhanced integrated MR-PET in non-small cell lung cancer patients.

Science.gov (United States)

Huang, Yu-Sen; Chen, Jenny Ling-Yu; Hsu, Feng-Ming; Huang, Jei-Yie; Ko, Wei-Chun; Chen, Yi-Chang; Jaw, Fu-Shan; Yen, Ruoh-Fang; Chang, Yeun-Chung

2018-01-01

To evaluate the response in patients undergoing SBRT using dynamic contrast-enhanced (DCE) integrated magnetic resonance positron emission tomography (MR-PET). Stereotactic body radiation therapy (SBRT) is efficacious as a front-line local treatment for non-small cell lung cancer (NSCLC). We prospectively enrolled 19 lung tumors in 17 nonmetastatic NSCLC patients who were receiving SBRT as a primary treatment. They underwent DCE-integrated 3T MR-PET before and 6 weeks after SBRT. The following image parameters were analyzed: tumor size, standardized uptake value (SUV), apparent diffusion coefficient, K trans , k ep , v e , v p , and iAUC 60 . Chest computed tomography (CT) was performed at 3 months after SBRT. SBRT treatment led to tumor changes including significant decreases in the SUV max (-61%, P PET SUV max was correlated with the MR k ep mean (P = 0.002) and k ep SD (P 10 (P = 0.083). In patients with NSCLC who are receiving SBRT, DCE-integrated MR-PET can be used to evaluate the response after SBRT and to predict the local treatment outcome. 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:191-199. © 2017 International Society for Magnetic Resonance in Medicine.

Efficacy evaluation of managed population shift in Ukraine from zone of obligate (compulsory) resettlement as a measure of public radiation protection.

Science.gov (United States)

Gunko, N V

2015-12-01

Evaluation of efficacy of the managed population transmigration from zone of obligate (compulsory) resettlement as a measure of civil protection after the Chernobyl NPP accident from the perspective of radiation biology. Legislative and statutory tutorial documents that regulate the managed population shift from radiologically contaminated territories of Ukraine and data from the Ukrainian State Service of Statistics on time limits and scopes of population transmigration from contaminated settlements were the informational back ground of the study. Data on retrospective and expected/anticipated radiation doses in population of settlements exposed to radiological contamination in Ukraine after the Chernobyl disaster summarized for the 1986-1997 peri od and up to 2055 were the information source for calculation of averted doses due to population shift. Battery of basic research empirical evidence review methods was applied under the calculation, systemic, and biomedical approach. Population shift from zone of obligate (compulsore) resettlement (hereafter referred to as Zone 2) to stop the radiation exposure as a tool of civil protection from emergency ionizing radiation after the Chernobyl NPP accident was scientifically substantiated and expedient from the perspective of radiation biology. Estimability of a managed population shift from "dose effect" perspective and "benefit/harm" principle is worse because of data absence on individual radiation doses to migrants in the country. Public shift in 1990 and 1991 was most effective from the viewpoint of level of averted lifetime dose. Due to transmigration the averted lifetime dose to the most vulnerable group of the Chernobyl disaster survivors i.e. children aged 0 years varied from 11.2 to 28.8 mSv (calculated for the Perejizdiv village council of Zhytomyr province). Since 2000 there was almost no public shift being not accomplished in the scheduled scope. Delay and incompleteness of transmigration have diminished the

Efficacy evaluation of managed population shift in Ukraine from zone of obligate (compulsory) resettlement as a measure of public radiation protection

International Nuclear Information System (INIS)

Gun'ko, N.V.

2015-01-01

Evaluation of efficacy of the managed population transmigration from zone of obligate (compulsory) resettlement as a measure of civil protection after the Chernobyl NPP accident from the perspective of radiation biology. Materials and methods. Legislative and statutory-tutorial documents that regulate the managed population shift from radiologically contaminated territories of Ukraine and data from the Ukrainian State Service of Statistics on time limits and scopes of population transmigration from contaminated settlements were the informational back ground of the study. Data on retrospective and expected/anticipated radiation doses in population of settlements exposed to radiological contamination in Ukraine after the Chernobyl disaster summarized for the 1986-1997 period and up to 2055 were the information source for calculation of averted doses due to population shift. Battery of basic research empirical evidence review methods was applied under the calculation, systemic, and biomedical approach. Population shift from zone of obligate (compulsory) resettlement (hereafter referred to as Zone 2) to stop the radiation exposure as a tool of civil protection from emergency ionizing radiation after the Chernobyl NPP accident was scientifically substantiated and expedient from the perspective of radiation biology. Estimability of a managed population shift from 'dose-effect' perspective and 'benefit/harm' principle is worse because of data absence on individual radiation doses to migrants in the country. Public shift in 1990 and 1991 was most effective from the viewpoint of level of averted lifetime dose. Due to transmigration the averted lifetime dose to the most vulnerable group of the Chernobyl disaster survivors i.e. children aged 0 years varied from 11.2 to 28.8 mSv (calculated for the Perejizdiv village council of Zhytomyr province). Since 2000 there was almost no public shift being not accomplished in the scheduled scope. Delay and incompleteness of

Radiative heat transfer between nanoparticles enhanced by intermediate particle

Directory of Open Access Journals (Sweden)

Yanhong Wang

2016-02-01

Full Text Available Radiative heat transfer between two polar nanostructures at different temperatures can be enhanced by resonant tunneling of surface polaritons. Here we show that the heat transfer between two nanoparticles is strongly varied by the interactions with a third nanoparticle. By controlling the size of the third particle, the time scale of thermalization toward the thermal bath temperature can be modified over 5 orders of magnitude. This effect provides control of temperature distribution in nanoparticle aggregation and facilitates thermal management at nanoscale.

Beta-Carotene production enhancement by UV-A radiation in Dunaliella bardawil cultivated in laboratory reactors

International Nuclear Information System (INIS)

Mogedas, B.; Casal, C.; Forjan, E.; Vilchez, C.

2009-01-01

beta-Carotene is an antioxidant molecule of commercial value that can be naturally produced by certain microalgae that mostly belong to the genus Dunaliella. So far, nitrogen starvation has been the most efficient condition for enhancing beta-carotene accumulation in Dunaliella. However, while nitrogen starvation promotes beta-carotene accumulation, the cells become non-viable; consequently under such conditions, continuous beta-carotene production is limited to less than 1 week. In this study, the use of UV-A radiation as a tool to enhance long-term beta-carotene production in Dunaliella bardawil cultures was investigated. The effect of UV-A radiation (320-400 nm) added to photosynthetically active radiation (PAR, 400-700 nm) on growth and carotenoid accumulation of D. bardawil in a laboratory air-fluidized bed photobioreactor was studied. The results were compared with those from D. bardawil control cultures incubated with PAR only. The addition of 8.7 W/square m UV-A radiation to 250 W/square m PAR stimulated long-term growth of D. bardawil. Throughout the exponential growth period the UV-A irradiated cultures showed enhanced carotenoid accumulation, mostly as beta-carotene. After 24 days, the concentration of beta-carotene in UV-A irradiated cultures was approximately two times that of control cultures. Analysis revealed that UV-A clearly induced major accumulation of all-trans beta-carotene. In N-starved culture media, beta-carotene biosynthesis in UV-A irradiated cultures was stimulated. We conclude that the addition of UV-A to PAR enhances carotenoid production processes, specifically all-trans beta-carotene, in D. bardawil cells without negative effects on cell growth

Metronomic Doses of Temozolomide Enhance the Efficacy of Carbon Nanotube CpG Immunotherapy in an Invasive Glioma Model.

Directory of Open Access Journals (Sweden)

Mao Ouyang

Full Text Available Even when treated with aggressive current therapies, most patients with glioblastoma survive less than two years. Rapid tumor growth, an invasive nature, and the blood-brain barrier, which limits the penetration of large molecules into the brain, all contribute to the poor tumor response associated with conventional therapies. Immunotherapy has emerged as a therapeutic approach that may overcome these challenges. We recently reported that single-walled carbon nanotubes (SWCNTs can be used to dramatically increase the immunotherapeutic efficacy of CpG oligonucleotides in a mouse model of glioma. Following implantation in the mouse brain, the tumor cell line used in these previous studies (GL261 tends to form a spherical tumor with limited invasion into healthy brain. In order to evaluate SWCNT/CpG therapy under more clinically-relevant conditions, here we report the treatment of a more invasive mouse glioma model (K-Luc that better recapitulates human disease. In addition, a CpG sequence previously tested in humans was used to formulate the SWCNT/CpG which was combined with temozolomide, the standard of care chemotherapy for glioblastoma patients. We found that, following two intracranial administrations, SWCNT/CpG is well-tolerated and improves the survival of mice bearing invasive gliomas. Interestingly, the efficacy of SWCNT/CpG was enhanced when combined with temozolomide. This enhanced anti-tumor efficacy was correlated to an increase of tumor-specific cytotoxic activity in splenocytes. These results reinforce the emerging understanding that immunotherapy can be enhanced by combining it with chemotherapy and support the continued development of SWCNT/CpG.

Low dose radiation enhance the anti-tumor effect of high dose radiation on human glioma cell U251

International Nuclear Information System (INIS)

Wang Chang; Wang Guanjun; Tan Yehui; Jiang Hongyu; Li Wei

2008-01-01

Objective: To detect the effect on the growth of human glioma cell U251 induced by low dose irradiation and low dose irradiation combined with large dose irradiation. Methods: Human glioma cell line U251 and nude mice carried with human glioma were used. The tumor cells and the mice were treated with low dose, high dose, and low dose combined high dose radiation. Cells growth curve, MTT and flow cytometry were used to detect the proliferation, cell cycle and apoptosis of the cells; and the tumor inhibition rate was used to assess the growth of tumor in vivo. Results: After low dose irradiation, there was no difference between experimental group and control group in cell count, MTT and flow cytometry. Single high dose group and low dose combined high dose group both show significantly the suppressing effect on tumor cells, the apoptosis increased and there was cell cycle blocked in G 2 period, but there was no difference between two groups. In vivo apparent anti-tumor effect in high dose radiation group and the combining group was observed, and that was more significant in the combining group; the prior low dose radiation alleviated the injury of hematological system. There was no difference between single low dose radiation group and control. Conclusions: There is no significant effect on human glioma cell induced by low dose radiation, and low dose radiation could not induce adaptive response. But in vivo experience, low dose radiation could enhance the anti-tumor effect of high dose radiation and alleviated the injury of hematological system. (authors)

Application of Ionizing Radiations to Produce New Polysaccharides and Proteins with Enhanced Functionality

International Nuclear Information System (INIS)

Al Assaf, S.

2006-01-01

Treatment of polysaccharides with ionizing radiation either in the solid state or in aqueous solution leads to degradation, whereas application of radiation to process synthetic polymers to introduce structural changes and special performance characteristics is now a thriving industry. Using a mediating gas associated during the radiation treatment prevents the degradation of natural polymers and enables the introduction of different molecular and functional characteristics, as previously achieved with synthetic polymers. For example, the molecular weight can be increased and standardised, protein distribution reorganised and modified to ensure better emulsification, viscosity and viscoelasticity enhanced, leading when required to hydrogel formation. More than one hydrocolloid can also be integrated into a single matrix using this process. Protein, within demineralised bone, too can be modified to give enhanced osteoinductive capacity. This experience has led to additional patented and proprietary processes, using standard food processing techniques, to promote changes in a wide range of hydrocolloids which emulates and extend those which occur naturally. The lecture will describe these structural changes and their functional role by reference to several hydrocolloids, including acacia gums, pectin, ispaghula and hyaluronan, bone morphogenic protein. Applications in food products, dietary fibre and medical products will be illustrated

Agonist anti-GITR antibody significantly enhances the therapeutic efficacy of Listeria monocytogenes-based immunotherapy.

Science.gov (United States)

Shrimali, Rajeev; Ahmad, Shamim; Berrong, Zuzana; Okoev, Grigori; Matevosyan, Adelaida; Razavi, Ghazaleh Shoja E; Petit, Robert; Gupta, Seema; Mkrtichyan, Mikayel; Khleif, Samir N

2017-08-15

We previously demonstrated that in addition to generating an antigen-specific immune response, Listeria monocytogenes (Lm)-based immunotherapy significantly reduces the ratio of regulatory T cells (Tregs)/CD4 + and myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. Since Lm-based immunotherapy is able to inhibit the immune suppressive environment, we hypothesized that combining this treatment with agonist antibody to a co-stimulatory receptor that would further boost the effector arm of immunity will result in significant improvement of anti-tumor efficacy of treatment. Here we tested the immune and therapeutic efficacy of Listeria-based immunotherapy combination with agonist antibody to glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) in TC-1 mouse tumor model. We evaluated the potency of combination on tumor growth and survival of treated animals and profiled tumor microenvironment for effector and suppressor cell populations. We demonstrate that combination of Listeria-based immunotherapy with agonist antibody to GITR synergizes to improve immune and therapeutic efficacy of treatment in a mouse tumor model. We show that this combinational treatment leads to significant inhibition of tumor-growth, prolongs survival and leads to complete regression of established tumors in 60% of treated animals. We determined that this therapeutic benefit of combinational treatment is due to a significant increase in tumor infiltrating effector CD4 + and CD8 + T cells along with a decrease of inhibitory cells. To our knowledge, this is the first study that exploits Lm-based immunotherapy combined with agonist anti-GITR antibody as a potent treatment strategy that simultaneously targets both the effector and suppressor arms of the immune system, leading to significantly improved anti-tumor efficacy. We believe that our findings depicted in this manuscript provide a promising and translatable strategy that can enhance the overall

CpG Oligodeoxynucleotides Enhance the Efficacy of Adoptive Cell Transfer Using Tumor Infiltrating Lymphocytes by Modifying the Th1 Polarization and Local Infiltration of Th17 Cells

Directory of Open Access Journals (Sweden)

Lin Xu

2010-01-01

Full Text Available Adoptive cell transfer immunotherapy using tumor infiltrating lymphocytes (TILs was an important therapeutic strategy against tumors. But the efficacy remains limited and development of new strategies is urgent. Recent evidence suggested that CpG-ODNs might be a potent candidate for tumor immunotherapy. Here we firstly reported that CpG-ODNs could significantly enhance the antitumor efficacy of adoptively transferred TILs in vivo accompanied by enhanced activity capacity and proliferation of CD8+ T cells and CD8+ T cells, as well as a Th1 polarization immune response. Most importantly, we found that CpG-ODNs could significantly elevate the infiltration of Th17 cells in tumor mass, which contributed to anti-tumor efficacy of TILs in vivo. Our findings suggested that CpG ODNs could enhance the anti-tumor efficacy of adoptively transferred TILs through modifying Th1 polarization and local infiltration of Th17 cells, which might provide a clue for developing a new strategy for ACT based on TILs.

Radiation-enhanced cytotoxicity of misonidazole

International Nuclear Information System (INIS)

Korbelik, M.; Palcic, B.; Skarsgard, L.D.

1981-01-01

The effect of ionizing radiation on the toxicity of misonidazole to hypoxic mammalian cells was examined. Cell toxicity response (log surviving fraction vs time of exposure to misonidazole in hypoxia) can be approximated by a biphasic curve: an initial period of approximately zero-slope shoulder, followed by exponential decrease in survival. Radiation reduced the zero-slope shoulder of toxicity response in a dose-dependent manner and at a given dose, the shoulder totally disappeared. The slope of the exponential region of the toxic response was unaffected. The same final survival level was achieved regardless of the sequence in which radiation and mixonidazole exposure were applied to cells; in fact, there was no detectable repair of that radiation-induced damage which interacts with misonidazole toxicity (up to 24 hr). A mechanism for this interaction is proposed. Clinical implications are considered assuming that similar interaction between the two modalities takes place in vivo. Since the shoulder of toxic responses is eliminated at high radiation doses, repeated administration of radiation and misonidazole could lead to additional kill of chronically and acutely hypoxic cells, if indeed both types are present in human tumors

Self-Efficacy for Coping with Cancer Enhances the Effect of Reiki Treatments During the Pre-Surgery Phase of Breast Cancer Patients.

Science.gov (United States)

Chirico, Andrea; D'Aiuto, Giuseppe; Penon, Antonella; Mallia, Luca; DE Laurentiis, Michelino; Lucidi, Fabio; Botti, Gerardo; Giordano, Antonio

2017-07-01

Self-efficacy for coping with cancer plays a critical role in influencing psychological cancer-related outcomes, some studies suggested its role in enhancing or reducing the effects of psychological interventions in cancer patients. Reiki has recently been included among the efficacious complementary therapeutic intervention for cancer patients. The present study evaluated the role of self-efficacy for coping with cancer as buffer of the Reiki treatment effects on cancer-related symptoms in a randomized controlled trial (intervention versus control group) of breast cancer patients (N=110) during the pre-surgery phase. Results showed that self-efficacy for coping with cancer can influence the effect of a Reiki treatment. Higher efficacious patients showed a more powerful effect of the Reiki intervention on both anxiety and mood than the low efficacious patients. From a practical perspective, the study provides insightful results for healthcare professionals. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Plasmon-enhanced optically stimulated luminescence

International Nuclear Information System (INIS)

Guidelli, E. J.; Baffa, O.; Ramos, A. P.

2015-10-01

Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

Plasmon-enhanced optically stimulated luminescence

Energy Technology Data Exchange (ETDEWEB)

Guidelli, E. J.; Baffa, O. [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Fisica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Ramos, A. P., E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Quimica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

2015-10-15

Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

Motivation Enhancement Therapy with pregnant substance-abusing women: does baseline motivation moderate efficacy?

Science.gov (United States)

Ondersma, Steven J; Winhusen, Theresa; Erickson, Sarah J; Stine, Susan M; Wang, Yun

2009-04-01

Some evidence suggests that motivational approaches are less efficacious--or even counter-productive--with persons who are relatively motivated at baseline. The present study was conducted to examine whether disordinal moderation by baseline motivation could partially explain negative findings in a previous study [Winhusen, T., Kropp, F., Babcock, D., Hague, D., Erickson, S.J., Renz, C., Rau, L., Lewis, D., Leimberger, J., Somoza, E., 2008. Motivational enhancement therapy to improve treatment utilization and outcome in pregnant substance users. J. Subst. Abuse Treat. 35, 161-173]. Analyses also focused on the relative utility of the University of Rhode Island Change Assessment (URICA) scale, vs. a single goal question as potential moderators of Motivation Enhancement Therapy (MET). Participants were 200 pregnant women presenting for substance abuse treatment at one of four sites. Women were randomly assigned to either a three-session MET condition or treatment as usual (TAU). Generalized Estimating Equations (GEE) revealed no significant moderation effects on drug use at post-treatment. At follow-up, contrary to expectations, participants who had not set a clear quit goal at baseline were less likely to be drug-free if randomized to MET (OR=0.48); participants who did set a clear quit goal were more likely to be drug-free if randomized to MET (OR=2.53). No moderating effects were identified via the URICA. Disordinal moderation of MET efficacy by baseline motivation may have contributed somewhat to the negative results of the [Winhusen, T., Kropp, F., Babcock, D., Hague, D., Erickson, S.J., Renz, C., Rau, L., Lewis, D., Leimberger, J., Somoza, E., 2008. Motivational enhancement therapy to improve treatment utilization and outcome in pregnant substance users. J. Subst. Abuse Treat. 35, 161-173] study, but in the opposite direction expected. A simple question regarding intent to quit may be useful in identifying persons who may differentially respond to motivational

Quantitative Simulation of QARBM Challenge Events During Radiation Belt Enhancements

Science.gov (United States)

Li, W.; Ma, Q.; Thorne, R. M.; Bortnik, J.; Chu, X.

2017-12-01

Various physical processes are known to affect energetic electron dynamics in the Earth's radiation belts, but their quantitative effects at different times and locations in space need further investigation. This presentation focuses on discussing the quantitative roles of various physical processes that affect Earth's radiation belt electron dynamics during radiation belt enhancement challenge events (storm-time vs. non-storm-time) selected by the GEM Quantitative Assessment of Radiation Belt Modeling (QARBM) focus group. We construct realistic global distributions of whistler-mode chorus waves, adopt various versions of radial diffusion models (statistical and event-specific), and use the global evolution of other potentially important plasma waves including plasmaspheric hiss, magnetosonic waves, and electromagnetic ion cyclotron waves from all available multi-satellite measurements. These state-of-the-art wave properties and distributions on a global scale are used to calculate diffusion coefficients, that are then adopted as inputs to simulate the dynamical electron evolution using a 3D diffusion simulation during the storm-time and the non-storm-time acceleration events respectively. We explore the similarities and differences in the dominant physical processes that cause radiation belt electron dynamics during the storm-time and non-storm-time acceleration events. The quantitative role of each physical process is determined by comparing against the Van Allen Probes electron observations at different energies, pitch angles, and L-MLT regions. This quantitative comparison further indicates instances when quasilinear theory is sufficient to explain the observed electron dynamics or when nonlinear interaction is required to reproduce the energetic electron evolution observed by the Van Allen Probes.

Enhancing radiation protection

International Nuclear Information System (INIS)

2006-01-01

When a new radiotherapy center in Gezira, Sudan, delivers its first therapeutic dose to a cancer patient, two things happen: A young man begins to regain his health and looks forward to being better able to support his family and contribute to his community; and a developing nation realizes an important step toward deriving the social and economic benefits of nuclear science. The strategic application of nuclear technology in particular fields- human health, industry, food and agriculture, energy, water resources and environmental protection - has enormous potential to help shape the future of developing countries. But past radiological incidents, several of which involved high levels of exposure or death (Bolivia, Brazil, Cost Rica, Georgia, Ghana, Morocco, Panama and Thailand), underscore the inherent and very serious risks. For this reason, the IAEA's Departments of Technical Cooperation and Nuclear Safety and Security partner closely, particularly in the area of radiation protection. They strive to consider every minute detail in the equation that brings together radiation sources, modern technologies, people and the environment. Launched in 1996, the Model Project on Upgrading Radiation Protection Infrastructure (the Model Project) aimed to help Member States: achieve capacities that underpin the safe and secure application of nuclear technologies; establish a legislative framework and regulatory infrastructure; develop exposure control mechanisms to protect workers, medical patients, the public and the environment; and achieve preparedness and planned response to radiological emergencies. In fact, the hospital scenario above typically marks several years of intense collaboration amongst scientists, legislators, regulators, politicians and administrators from both Member States and the IAEA, orchestrated and aided by regional managers and technical experts from the IAEA. As radiation protection team members can attest, every application of nuclear technology

Dose of radiation enhancement, using silver nanoparticles in a human tissue equivalent gel dosimeter.

Science.gov (United States)

Hassan, Muhammad; Waheed, Muhammad Mohsin; Anjum, Muhammad Naeem

2016-01-01

To quantify the radiation dose enhancement in a human tissue-equivalent polymer gel impregnated with silver nanoparticles. The case-control study was conducted at the Bahawalpur Institute of Nuclear Medicine and Oncology, Bahawalpur, Pakistan, in January 2014. Silver nanoparticles used in this study were prepared by wet chemical method. Polymer gel was prepared by known quantity of gelatine, methacrylic acid, ascorbic acid, copper sulphate pentahydrate, hydroquinone and water. Different concentrations of silver nanoparticles were added to the gel during its cooling process. The gel was cooled in six plastic vials of 50ml each. Two vials were used as a control sample while four vials were impregnated with silver nanoparticles. After 22 hours, the vials were irradiated with gamma rays by aCobalt-60 unit. Radiation enhancement was assessed by taking magnetic resonance images of the vials. The images were analysed using Image J software. The dose enhancement factor was 24.17% and 40.49% for 5Gy and 10Gy dose respectively. The dose enhancement factor for the gel impregnated with 0.10mM silver nanoparticles was 32.88% and 51.98% for 5Gy and 10Gy dose respectively. The impregnation of a tissue-equivalent gel with silver nanoparticles resulted in dose enhancement and this effect was magnified up to a certain level with the increase in concentration of silver nanoparticles.

Can feedback analysis be used to uncover the physical origin of climate sensitivity and efficacy differences?

Science.gov (United States)

Rieger, Vanessa S.; Dietmüller, Simone; Ponater, Michael

2017-10-01

Different strengths and types of radiative forcings cause variations in the climate sensitivities and efficacies. To relate these changes to their physical origin, this study tests whether a feedback analysis is a suitable approach. For this end, we apply the partial radiative perturbation method. Combining the forward and backward calculation turns out to be indispensable to ensure the additivity of feedbacks and to yield a closed forcing-feedback-balance at top of the atmosphere. For a set of CO2-forced simulations, the climate sensitivity changes with increasing forcing. The albedo, cloud and combined water vapour and lapse rate feedback are found to be responsible for the variations in the climate sensitivity. An O3-forced simulation (induced by enhanced NOx and CO surface emissions) causes a smaller efficacy than a CO2-forced simulation with a similar magnitude of forcing. We find that the Planck, albedo and most likely the cloud feedback are responsible for this effect. Reducing the radiative forcing impedes the statistical separability of feedbacks. We additionally discuss formal inconsistencies between the common ways of comparing climate sensitivities and feedbacks. Moreover, methodical recommendations for future work are given.

Production of narrowband tunable extreme-ultraviolet radiation by noncollinear resonance-enhanced four-wave mixing

NARCIS (Netherlands)

Hannemann, S.; Hollenstein, U.; van Duijn, E.J.; Ubachs, W.M.G.

2005-01-01

Fourier-transform-limited extreme-ultraviolet (XUV) radiation (bandwidth ≲300 MHz) tunable around 91 nm is produced by use of two-photon resonance-enhanced four-wave mixing on the Kr resonance at 94 093 cm

SU-G-TeP3-15: Radiation Dose Enhancement by Anatase TiO2NPs

Energy Technology Data Exchange (ETDEWEB)

Youkhana, E; Geso, M; Feltis, B [RMIT University, Melbourne, VIC (Australia)

2016-06-15

Purpose: This work investigates radiation dose enhancement caused by TiO2 nanoparticles covering entire X-ray energy ranges used in radiation therapy. Methods: Anatase TiO2NPs crystal were synthesised and modified as hydrophilic and hydrophobic to disperse in culture-medium and halocarbons (PRESAGE chemical composition) respectively. TiO2NPs were characterised using TEM, XPS, XRD, TGA and FTIR. Various Concentrations have been utilised for determination of radiation-dose enhancement. This investigation is carried out in two ways; one using PRESAGE dosimeter/phantom and the other is radiobiological and based on in vitro study using two types of cell lines, Human Keratinocyte (HaCaT) and prostate cancer cell lines. The x-ray used are both kilovoltage and megavoltage separately. The prepared PRESAGE dosimeters were scanned using optical CT scanner. Clonogenic and MTS assays were employed for cell cytotoxicity and viability measurements for determination of the levels of dose enhancement. Results: Significant about (50%, 45%) dose enhancement by TiO2-NPs for kV x-rays is measured in both ways (Presage and Cells study). Slightly more is detected with the cells. However, the dose enhancement with megavoltage beams was insignificant using Presage and under same conditions the cells survival curves indicates around 20% which is relatively high. This difference can only be attributed to some biochemical effects. Such as generation of reactive oxygen species (ROS), this can affect the cells while it can’t be detected by Presage. Elevation of hydroxyl radicals (•OH) of many orders is observed with the inclusion of TiO2-NPs in cells-medium. Conclusion: Dose enhancement inflicted by TiO2-NPs is proven to be significant with megavoltage beams and minimal with kV. The high dose enhancements obtained can be attributed to higher levels of ROS generated. Since MV beams are most commonly used, this research proves potential value for more efficient beam delivery. This has

Chloroquine enhances the efficacy of cisplatin by suppressing autophagy in human adrenocortical carcinoma treatment

Directory of Open Access Journals (Sweden)

Qin L

2016-03-01

Full Text Available Liang Qin,1,* Tianyuan Xu,1,* Leilei Xia,1 Xianjin Wang,1 Xiang Zhang,1 Xiaohua Zhang,1 Zhaowei Zhu,1 Shan Zhong,1 Chuandong Wang,2 Zhoujun Shen1 1Department of Urology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 2Key Laboratory of Stem Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: It has been demonstrated that chloroquine (CQ enhances the efficacy of chemotherapy. However, little is known about whether CQ could enhance the efficacy of cisplatin (DDP in the treatment of adrenocortical carcinoma (ACC. In this study, we explore the efficacy and mechanism by which CQ affects DDP sensitivity in human ACC in vitro and in vivo.Methods: The autophagic gene Beclin-1 expression was detected by immunohistochemistry, and the protein levels were analyzed using immunoblotting assays of ACC tissues and normal adrenal cortex tissues. The ACC SW13 cells were treated with DDP and/or CQ. The cell viability assay was performed using the MTT method. Qualitative autophagy detection was performed by monodansylcadaverine staining of autophagic vacuoles. Annexin V-fluorescein isothiocyanate/propidium iodide double staining was used to count cell apoptosis by flow cytometry. The autophagy-related protein (Beclin-1, LC3, and p62 and apoptosis relative protein (Bax and Bcl-2 levels were evaluated with Western blot analysis. Furthermore, a murine model of nude BALB/c mice bearing SW13 cell xenografts was established to evaluate the efficacy of concomitant therapy.Results: The expression of the autophagic gene Beclin-1 was significantly downregulated in ACC tissues compared to normal adrenal cortex tissues. The Beclin-1 protein level in ACC tissues was lower than that in normal adrenal cortex tissues (P<0.05. In vitro concomitant therapy (DDP and CQ was more

Enzastaurin (LY317615), a Protein Kinase C Beta Selective Inhibitor, Enhances Antiangiogenic Effect of Radiation

International Nuclear Information System (INIS)

Willey, Christopher D.; Xiao Dakai; Tu Tianxiang; Kim, Kwang Woon; Moretti, Luigi; Niermann, Kenneth J.; Tawtawy, Mohammed N.; Quarles, Chad C. Ph.D.; Lu Bo

2010-01-01

Purpose: Angiogenesis has generated interest in oncology because of its important role in cancer growth and progression, particularly when combined with cytotoxic therapies, such as radiotherapy. Among the numerous pathways influencing vascular growth and stability, inhibition of protein kinase B(Akt) or protein kinase C(PKC) can influence tumor blood vessels within tumor microvasculature. Therefore, we wanted to determine whether PKC inhibition could sensitize lung tumors to radiation. Methods and Materials: The combination of the selective PKCβ inhibitor Enzastaurin (ENZ, LY317615) and ionizing radiation were used in cell culture and a mouse model of lung cancer. Lung cancer cell lines and human umbilical vascular endothelial cells (HUVEC) were examined using immunoblotting, cytotoxic assays including cell proliferation and clonogenic assays, and Matrigel endothelial tubule formation. In vivo, H460 lung cancer xenografts were examined for tumor vasculature and proliferation using immunohistochemistry. Results: ENZ effectively radiosensitizes HUVEC within in vitro models. Furthermore, concurrent ENZ treatment of lung cancer xenografts enhanced radiation-induced destruction of tumor vasculature and proliferation by IHC. However, tumor growth delay was not enhanced with combination treatment compared with either treatment alone. Analysis of downstream effectors revealed that HUVEC and the lung cancer cell lines differed in their response to ENZ and radiation such that only HUVEC demonstrate phosphorylated S6 suppression, which is downstream of mTOR. When ENZ was combined with the mTOR inhibitor, rapamycin, in H460 lung cancer cells, radiosensitization was observed. Conclusion: PKC appears to be crucial for angiogenesis, and its inhibition by ENZ has potential to enhance radiotherapy in vivo.

Pre- and post-exposure safety and efficacy of attenuated rabies virus vaccines are enhanced by their expression of IFNγ

Energy Technology Data Exchange (ETDEWEB)

Barkhouse, Darryll A. [Department of Cancer Biology, 1020 Locust St., Jefferson Alumni Hall, Room 454, Philadelphia, PA 19107 (United States); Center for Neurovirology 1020 Locust St., Jefferson Alumni Hall, Room 454, Philadelphia, PA 19107 (United States); Faber, Milosz [Center for Neurovirology 1020 Locust St., Jefferson Alumni Hall, Room 454, Philadelphia, PA 19107 (United States); Department of Microbiology and Immunology 1020 Locust St., Jefferson Alumni Hall, Room 465, Philadelphia, PA 19107 (United States); Hooper, D. Craig, E-mail: douglas.hooper@jefferson.edu [Department of Cancer Biology, 1020 Locust St., Jefferson Alumni Hall, Room 454, Philadelphia, PA 19107 (United States); Department of Neurological Surgery, 1020 Locust St., Jefferson Alumni Hall, Room 454, Philadelphia, PA 19107 (United States); Center for Neurovirology 1020 Locust St., Jefferson Alumni Hall, Room 454, Philadelphia, PA 19107 (United States)

2015-01-01

Consistent with evidence of a strong correlation between interferon gamma (IFNγ) production and rabies virus (RABV) clearance from the CNS, we recently demonstrated that engineering a pathogenic RABV to express IFNγ highly attenuates the virus. Reasoning that IFNγ expression by RABV vaccines would enhance their safety and efficacy, we reverse-engineered two proven vaccine vectors, GAS and GASGAS, to express murine IFNγ. Mortality and morbidity were monitored during suckling mice infection, immunize/challenge experiments and mixed intracranial infections. We demonstrate that GASγ and GASγGAS are significantly attenuated in suckling mice compared to the GASGAS vaccine. GASγ better protects mice from lethal DRV4 RABV infection in both pre- and post-exposure experiments compared to GASGAS. Finally, GASγGAS reduces post-infection neurological sequelae, compared to control, during mixed intracranial infection with DRV4. These data show IFNγ expression by a vaccine vector can enhance its safety while increasing its efficacy as pre- and post-exposure treatment. - Highlights: • IFNγ expression improves attenuated rabies virus safety and immunogenicity. • IFNγ expression is safer and more immunogenic than doubling glycoprotein expression. • Co-infection with IFNγ-expressing RABV prevents wild-type rabies virus lethality. • Vaccine safety and efficacy is additive for IFNγ and double glycoprotein expression.

Pre- and post-exposure safety and efficacy of attenuated rabies virus vaccines are enhanced by their expression of IFNγ

International Nuclear Information System (INIS)

Barkhouse, Darryll A.; Faber, Milosz; Hooper, D. Craig

2015-01-01

Consistent with evidence of a strong correlation between interferon gamma (IFNγ) production and rabies virus (RABV) clearance from the CNS, we recently demonstrated that engineering a pathogenic RABV to express IFNγ highly attenuates the virus. Reasoning that IFNγ expression by RABV vaccines would enhance their safety and efficacy, we reverse-engineered two proven vaccine vectors, GAS and GASGAS, to express murine IFNγ. Mortality and morbidity were monitored during suckling mice infection, immunize/challenge experiments and mixed intracranial infections. We demonstrate that GASγ and GASγGAS are significantly attenuated in suckling mice compared to the GASGAS vaccine. GASγ better protects mice from lethal DRV4 RABV infection in both pre- and post-exposure experiments compared to GASGAS. Finally, GASγGAS reduces post-infection neurological sequelae, compared to control, during mixed intracranial infection with DRV4. These data show IFNγ expression by a vaccine vector can enhance its safety while increasing its efficacy as pre- and post-exposure treatment. - Highlights: • IFNγ expression improves attenuated rabies virus safety and immunogenicity. • IFNγ expression is safer and more immunogenic than doubling glycoprotein expression. • Co-infection with IFNγ-expressing RABV prevents wild-type rabies virus lethality. • Vaccine safety and efficacy is additive for IFNγ and double glycoprotein expression

Changes in self-efficacy, collective efficacy and patient outcome following interprofessional simulation training on postpartum haemorrhage.

Science.gov (United States)

Egenberg, Signe; Øian, Pål; Eggebø, Torbjørn Moe; Arsenovic, Mirjana Grujic; Bru, Lars Edvin

2017-10-01

To examine whether interprofessional simulation training on management of postpartum haemorrhage enhances self-efficacy and collective efficacy and reduces the blood transfusion rate after birth. Postpartum haemorrhage is a leading cause of maternal morbidity and mortality worldwide, although it is preventable in most cases. Interprofessional simulation training might help improve the competence of health professionals dealing with postpartum haemorrhage, and more information is needed to determine its potential. Multimethod, quasi-experimental, pre-post intervention design. Interprofessional simulation training on postpartum haemorrhage was implemented for midwives, obstetricians and auxiliary nurses in a university hospital. Training included realistic scenarios and debriefing, and a measurement scale for perceived postpartum haemorrhage-specific self-efficacy, and collective efficacy was developed and implemented. Red blood cell transfusion was used as the dependent variable for improved patient outcome pre-post intervention. Self-efficacy and collective efficacy levels were significantly increased after training. The overall red blood cell transfusion rate did not change, but there was a significant reduction in the use of ≥5 units of blood products related to severe bleeding after birth. The study contributes to new knowledge on how simulation training through mastery and vicarious experiences, verbal persuasion and psychophysiological state might enhance postpartum haemorrhage-specific self-efficacy and collective efficacy levels and thereby predict team performance. The significant reduction in severe postpartum haemorrhage after training, indicated by reduction in ≥5 units of blood transfusions, corresponds well with the improvement in collective efficacy, and might reflect the emphasis on collective efforts to counteract severe cases of postpartum haemorrhage. Interprofessional simulation training in teams may contribute to enhanced prevention and

Enhancement of radiation response in human hepatocarcinoma cells by Metformin

Energy Technology Data Exchange (ETDEWEB)

Kim, Eun Ho; Kim, Won Woo; Kim, Joon; Jung, Won Gyun [Division of heavy ion clinical research, Korea University, Seoul (Korea, Republic of); Jeong, Jae Hoon; Jeong, Youn Kyoung; Kim, Mi Sook [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2012-11-15

Metformin (1, 1-dimethylbiguanide hydrochloride), the most widely used drug to treat type 2 diabetic patients under benefit good tolerability profile and low cost, has sparked keen interest as potential anticancer agent. Preclinical studies showed that the primary mechanism of action of metformin is through its ability to activate AMP-activated protein kinase (AMPK). Metformin inhibits complex 1 in the mitochondrial electron transport chain, leading to an increase in the AMP-to-ATP ratio, then, phospholylated AMPK increase energy generation or suppress energy consumption and then, inhibits cell growth. However, important caveat in direct action theory of metformin is that millimorlar range, effective dose for inhibition tumor cell growth in vitro, cannot be achieved in patients. This is probably because metformin enter cells through the organic cation transporters OCT1 and OCT2, which is lowly expressed in human cells except liver and adipose cells. dependent pathway rather than through direct effects of the tumor cells. We analyzed combination effect of metformin and radiation focusing to HCC cell lines, which theoretically express high organic cation transporters, producing high centration of metformin in tumor cells. The purpose of this study is to investigate whether metformin had anti-tumor effects when combined with radiation as radiosensitizer in HCC. The results showed that metformin increased radiosensitizing efficacy in HCC cells , as well as in Huh7 xenograft mouse models. Interestingly, metformin effectively sensitizes IR-induced apoptosis in HCC through upregulation of cleaved PARP and caspase3 and increase synergically on DNA damage response with combined treatment.HCC, suggesting potential usefulness of combined therapy of metformin together with radiation for HCC cancer therapy.

Enhancement of radiation response in human hepatocarcinoma cells by Metformin

International Nuclear Information System (INIS)

Kim, Eun Ho; Kim, Won Woo; Kim, Joon; Jung, Won Gyun; Jeong, Jae Hoon; Jeong, Youn Kyoung; Kim, Mi Sook

2012-01-01

Metformin (1, 1-dimethylbiguanide hydrochloride), the most widely used drug to treat type 2 diabetic patients under benefit good tolerability profile and low cost, has sparked keen interest as potential anticancer agent. Preclinical studies showed that the primary mechanism of action of metformin is through its ability to activate AMP-activated protein kinase (AMPK). Metformin inhibits complex 1 in the mitochondrial electron transport chain, leading to an increase in the AMP-to-ATP ratio, then, phospholylated AMPK increase energy generation or suppress energy consumption and then, inhibits cell growth. However, important caveat in direct action theory of metformin is that millimorlar range, effective dose for inhibition tumor cell growth in vitro, cannot be achieved in patients. This is probably because metformin enter cells through the organic cation transporters OCT1 and OCT2, which is lowly expressed in human cells except liver and adipose cells. dependent pathway rather than through direct effects of the tumor cells. We analyzed combination effect of metformin and radiation focusing to HCC cell lines, which theoretically express high organic cation transporters, producing high centration of metformin in tumor cells. The purpose of this study is to investigate whether metformin had anti-tumor effects when combined with radiation as radiosensitizer in HCC. The results showed that metformin increased radiosensitizing efficacy in HCC cells , as well as in Huh7 xenograft mouse models. Interestingly, metformin effectively sensitizes IR-induced apoptosis in HCC through upregulation of cleaved PARP and caspase3 and increase synergically on DNA damage response with combined treatment.HCC, suggesting potential usefulness of combined therapy of metformin together with radiation for HCC cancer therapy

Resonance-enhanced two-photon ionization of ions by Lyman alpha radiation in gaseous nebulae.

Science.gov (United States)

Johansson, S; Letokhov, V

2001-01-26

One of the mysteries of nebulae in the vicinity of bright stars is the appearance of bright emission spectral lines of ions, which imply fairly high excitation temperatures. We suggest that an ion formation mechanism, based on resonance-enhanced two-photon ionization (RETPI) by intense H Lyman alpha radiation (wavelength of 1215 angstroms) trapped inside optically thick nebulae, can produce these spectral lines. The rate of such an ionization process is high enough for rarefied gaseous media where the recombination rate of the ions formed can be 10(-6) to 10(-8) per second for an electron density of 10(3) to 10(5) per cubic centimeter in the nebula. Under such conditions, the photo-ions formed may subsequently undergo further RETPI, catalyzed by intense He i and He ii radiation, which also gets enhanced in optically thick nebulae that contain enough helium.

Plasmonically Enhanced Reflectance of Heat Radiation from Low-Bandgap Semiconductor Microinclusions.

Science.gov (United States)

Tang, Janika; Thakore, Vaibhav; Ala-Nissila, Tapio

2017-07-18

Increased reflectance from the inclusion of highly scattering particles at low volume fractions in an insulating dielectric offers a promising way to reduce radiative thermal losses at high temperatures. Here, we investigate plasmonic resonance driven enhanced scattering from microinclusions of low-bandgap semiconductors (InP, Si, Ge, PbS, InAs and Te) in an insulating composite to tailor its infrared reflectance for minimizing thermal losses from radiative transfer. To this end, we compute the spectral properties of the microcomposites using Monte Carlo modeling and compare them with results from Fresnel equations. The role of particle size-dependent Mie scattering and absorption efficiencies, and, scattering anisotropy are studied to identify the optimal microinclusion size and material parameters for maximizing the reflectance of the thermal radiation. For composites with Si and Ge microinclusions we obtain reflectance efficiencies of 57-65% for the incident blackbody radiation from sources at temperatures in the range 400-1600 °C. Furthermore, we observe a broadbanding of the reflectance spectra from the plasmonic resonances due to charge carriers generated from defect states within the semiconductor bandgap. Our results thus open up the possibility of developing efficient high-temperature thermal insulators through use of the low-bandgap semiconductor microinclusions in insulating dielectrics.

Acoustic Radiation Force Impulse Elastography for Efficacy Evaluation after Hepatocellular Carcinoma Radiofrequency Ablation: A Comparative Study with Contrast-Enhanced Ultrasound

Directory of Open Access Journals (Sweden)

Xiaohong Xu

2014-01-01

Full Text Available Aim. To explore acoustic radiation force impulse (ARFI elastography in assessing residual tumors of hepatocellular carcinoma (HCC after radiofrequency ablation (RFA. Materials and Methods. There were 83 HCC lesions among 72 patients. All patients were examined with ARFI, contrast enhanced ultrasound (CEUS, and CT or MRI. Tumor brightness on virtual touch tissue imaging (VTI and shear wave velocity (SWV were assessed before and approximately one month after RFA. Results. There were 14 residual tumors after RFA. VTI showed that all the tumors were darker after RFA. VTI was not able to distinguish the ablated lesions and the residual tumors. 13 residual tumor lesions were detected by CEUS. All completely ablated nodules had SWV demonstration of x.xx., while with those residual nodules, 6 tumors had x.xx measurement and 8 tumors had measurable SWV. nine lesions with residual tumors occurred in cirrhosis subjects and 5 lesions with residual tumors occurred in fibrosis subjects; there was no residual tumor in the normal liver subjects. Conclusion. VTI technique cannot demonstrate residual tumor post RFA. While SWV measurement of less than x.xx is likely associated with residual tumors, measurement of less than x.xx cannot exclude residual tumors. Liver cirrhosis is associated with decreased chance of a complete ablation.

Acoustic Radiation Force Impulse Elastography for Efficacy Evaluation after Hepatocellular Carcinoma Radiofrequency Ablation: A Comparative Study with Contrast-Enhanced Ultrasound

Science.gov (United States)

Xu, Xiaohong; Luo, Liangping; Chen, Jiexin; Wang, Jiexin; Zhou, Honglian; Li, Mingyi; Jin, Zhanqiang; Chen, Nianping; Miao, Huilai; Lin, Manzhou; Dai, Wei; Ahuja, Anil T.; Wang, Yi-Xiang J.

2014-01-01

Aim. To explore acoustic radiation force impulse (ARFI) elastography in assessing residual tumors of hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA). Materials and Methods. There were 83 HCC lesions among 72 patients. All patients were examined with ARFI, contrast enhanced ultrasound (CEUS), and CT or MRI. Tumor brightness on virtual touch tissue imaging (VTI) and shear wave velocity (SWV) were assessed before and approximately one month after RFA. Results. There were 14 residual tumors after RFA. VTI showed that all the tumors were darker after RFA. VTI was not able to distinguish the ablated lesions and the residual tumors. 13 residual tumor lesions were detected by CEUS. All completely ablated nodules had SWV demonstration of x.xx., while with those residual nodules, 6 tumors had x.xx measurement and 8 tumors had measurable SWV. nine lesions with residual tumors occurred in cirrhosis subjects and 5 lesions with residual tumors occurred in fibrosis subjects; there was no residual tumor in the normal liver subjects. Conclusion. VTI technique cannot demonstrate residual tumor post RFA. While SWV measurement of less than x.xx is likely associated with residual tumors, measurement of less than x.xx cannot exclude residual tumors. Liver cirrhosis is associated with decreased chance of a complete ablation. PMID:24895624

Surface-enhanced Raman scattering active gold nanostructure fabricated by photochemical reaction of synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Akinobu, E-mail: yamaguti@lasti.u-hyogo.ac.jp [Laboratory of Advance Science and Technology for Industry, University of Hyogo, 3-1-2 Koto, Kamigori, Ako, Hyogo 678-1205 (Japan); Matsumoto, Takeshi [Laboratory of Advance Science and Technology for Industry, University of Hyogo, 3-1-2 Koto, Kamigori, Ako, Hyogo 678-1205 (Japan); Okada, Ikuo; Sakurai, Ikuya [Synchrotoron Radiation Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Utsumi, Yuichi [Laboratory of Advance Science and Technology for Industry, University of Hyogo, 3-1-2 Koto, Kamigori, Ako, Hyogo 678-1205 (Japan)

2015-06-15

The deposition of gold nanoparticles in an electroplating solution containing gold (I) trisodium disulphite under synchrotron X-ray radiation was investigated. The nanoparticles grew and aggregated into clusters with increasing radiation time. This behavior is explained by evaluating the effect of Derjaguin-Landau-Verweyand-Overbeek (DLVO) interactions combining repulsive electrostatic and attractive van der Waals forces on the particle deposition process. The surface-enhanced Raman scattering (SERS) of 4,4′ -bipyridine (4bpy) in aqueous solution was measured using gold nanoparticles immobilized on silicon substrates under systematically-varied X-ray exposure. The substrates provided an in situ SERS spectrum for 1 nM 4bpy. This demonstration creates new opportunities for chemical and environmental analyses through simple SERS measurements. - Highlights: • Gold nanoparticles were produced by photochemical reaction of synchrotron radiation. • The gold nanoparticles grew and aggregated into the higher-order nanostructure. • The behavior is qualitatively explained by analytical estimation. • The surface-enhanced Raman spectroscopy of 4,4′-bipyridine (4bpy) was demonstrated. • The substrate fabricated in a suitable condition provides in situ SERS for 1 nM 4bpy.

FORMATION OF CARBON-ENHANCED METAL-POOR STARS IN THE PRESENCE OF FAR-ULTRAVIOLET RADIATION

Energy Technology Data Exchange (ETDEWEB)

Bovino, S.; Schleicher, D. R. G.; Latif, M. A. [Institut für Astrophysik Georg-August-Universität, Friedrich-Hund Platz 1, 37077 Göttingen (Germany); Grassi, T., E-mail: sbovino@astro.physik.uni-goettingen.de [Centre for Star and Planet Formation, Natural History Museum of Denmark, Øster Voldgade 5-7, 1350 Copenhagen (Denmark)

2014-08-01

Recent discoveries of carbon-enhanced metal-poor stars like SMSS J031300.36–670839.3 provide increasing observational insights into the formation conditions of the first second-generation stars in the universe, reflecting the chemical conditions after the first supernova explosion. Here, we present the first cosmological simulations with a detailed chemical network including primordial species as well as C, C{sup +}, O, O{sup +}, Si, Si{sup +}, and Si{sup 2+} following the formation of carbon-enhanced metal-poor stars. The presence of background UV flux delays the collapse from z = 21 to z = 15 and cool the gas down to the cosmic microwave background temperature for a metallicity of Z/Z {sub ☉} = 10{sup –3}. This can potentially lead to the formation of lower-mass stars. Overall, we find that the metals have a stronger effect on the collapse than the radiation, yielding a comparable thermal structure for large variations in the radiative background. We further find that radiative backgrounds are not able to delay the collapse for Z/Z {sub ☉} = 10{sup –2} or a carbon abundance as in SMSS J031300.36–670839.3.

Enhancement of tumor response by MEK inhibitor in murine HCa-I tumors

International Nuclear Information System (INIS)

Kim, Sung Hee; Seong, Jin Sil

2003-01-01

Extracellular signal-regulated kinase (ERK), which is part of the mitogen-activated protein kinase cascade, opposes initiation of the apoptotic cell death which is programmed by diverse cytotoxic stimuli. In this regard, the inhibition of ERK may be useful in improving the therapeutic efficacy of established anticancer agents. Murine hepatocarcinoma, HCa-l is known to be highly radioresistant with a TCD50 (radiation dose yield in 50% cure) of more than 80 Gy. Various anticancer drugs have been found to enhance the radioresponse of this particular tumor but none were successful. The objective of this study was to explore whether the selective inhibition of MEK could potentiate the antitumor efficacy of radiation in vivo, particularly in the case of radioresistant tumor. C3H/HeJ mice bearing 7.5-8 mm. HCa-l, were treated with PD98059 (intratumoral injection of 0.16 μg in 50 μl). Downregulation of ERK by PD98059 was most prominent 1h after the treatment. In the tumor growth delay assay, the drug was found to increase the effect of the tumor radioresponse with an enhancement factor (EF) of 1.6 and 1.87. Combined treatment of 25 Gy radiation with PD98059 significantly increased radiation induced apoptosis. The peak apoptotic index (number of apoptotic nuclei in 1000 nuclei X100) was 1.2% in the case of radiation treatment alone, 0.9% in the case of drug treatment alone and 4.9%, 5.3% in the combination treatment group. An analysis of apoptosis regulating molecules with Western blotting showed up regulation of p53, p21 WAF1 / CIP1 and Bcl-X s in the combination treatment group as compared to their levels in either the radiation alone or drug alone treatment groups. The level of other molecules such as Bcl-X L , Bax and BCI-2 were changed to a lesser extent. The selective inhibition of MEK in combination with radiation therapy may have potential benefit in cancer treatment

Enhancement of tumor response by MEK inhibitor in murine HCa-I tumors

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Hee; Seong, Jin Sil [College of Medicine, Yonsei Univ., Seoul (Korea, Republic of)

2003-09-01

Extracellular signal-regulated kinase (ERK), which is part of the mitogen-activated protein kinase cascade, opposes initiation of the apoptotic cell death which is programmed by diverse cytotoxic stimuli. In this regard, the inhibition of ERK may be useful in improving the therapeutic efficacy of established anticancer agents. Murine hepatocarcinoma, HCa-l is known to be highly radioresistant with a TCD50 (radiation dose yield in 50% cure) of more than 80 Gy. Various anticancer drugs have been found to enhance the radioresponse of this particular tumor but none were successful. The objective of this study was to explore whether the selective inhibition of MEK could potentiate the antitumor efficacy of radiation in vivo, particularly in the case of radioresistant tumor. C3H/HeJ mice bearing 7.5-8 mm. HCa-l, were treated with PD98059 (intratumoral injection of 0.16 {mu}g in 50 {mu}l). Downregulation of ERK by PD98059 was most prominent 1h after the treatment. In the tumor growth delay assay, the drug was found to increase the effect of the tumor radioresponse with an enhancement factor (EF) of 1.6 and 1.87. Combined treatment of 25 Gy radiation with PD98059 significantly increased radiation induced apoptosis. The peak apoptotic index (number of apoptotic nuclei in 1000 nuclei X100) was 1.2% in the case of radiation treatment alone, 0.9% in the case of drug treatment alone and 4.9%, 5.3% in the combination treatment group. An analysis of apoptosis regulating molecules with Western blotting showed up regulation of p53, p21{sup WAF1}/{sup CIP1} and Bcl-X{sub s} in the combination treatment group as compared to their levels in either the radiation alone or drug alone treatment groups. The level of other molecules such as Bcl-X{sub L}, Bax and BCI-2 were changed to a lesser extent. The selective inhibition of MEK in combination with radiation therapy may have potential benefit in cancer treatment.

Enhancing Self-Efficacy and Performance: An Experimental Comparison of Psychological Techniques.

Science.gov (United States)

Wright, Bradley James; O'Halloran, Paul Daniel; Stukas, Arthur Anthony

2016-01-01

We assessed how 6 psychological performance enhancement techniques (PETs) differentially improved self-efficacy (SE) and skill performance. We also assessed whether vicarious experiences and verbal persuasion as posited sources of SE (Bandura, 1982 ) were supported and, further, if the effects of the 6 PETs remained after controlling for achievement motivation traits and self-esteem. A within-subject design assessed each individual across 2 trials for 3 disparate PETs. A between-groups design assessed differences between PETs paired against each other for 3 similar novel tasks. Participants (N = 96) performed 2 trials of 10 attempts at each of the tasks (kick, throw, golf putt) in a counterbalanced sequence using their nondominant limb. Participants completed the Sport Orientation Questionnaire, Rosenberg Self-Esteem Scale, and General Self-Efficacy Scale and were randomly allocated to either the modeling or imagery, goal-setting or instructional self-statement, or knowledge-of-results or motivational feedback conditions aligned with each task. An instructional self-statement improved performance better than imagery, modeling, goal setting, and motivational and knowledge-of-results augmented feedback. Motivational auditory feedback most improved SE. Increased SE change scores were related to increased performance difference scores on all tasks after controlling for age, sex, achievement motivation, and self-esteem. Some sources of SE may be more influential than others on both SE and performance improvements. We provide partial support for the sources of SE proposed by Bandura's social-cognitive theory with verbal persuasion but not vicarious experiences improving SE.

Rational design of a comprehensive cancer therapy platform using temperature-sensitive polymer grafted hollow gold nanospheres: simultaneous chemo/photothermal/photodynamic therapy triggered by a 650 nm laser with enhanced anti-tumor efficacy

Science.gov (United States)

Deng, Xiaoran; Chen, Yinyin; Cheng, Ziyong; Deng, Kerong; Ma, Ping'an; Hou, Zhiyao; Liu, Bei; Huang, Shanshan; Jin, Dayong; Lin, Jun

2016-03-01

Combining multi-model treatments within one single system has attracted great interest for the purpose of synergistic therapy. In this paper, hollow gold nanospheres (HAuNs) coated with a temperature-sensitive polymer, poly(oligo(ethylene oxide) methacrylate-co-2-(2-methoxyethoxy)ethyl methacrylate) (p(OEGMA-co-MEMA)), co-loaded with DOX and a photosensitizer Chlorin e6 (Ce6) were successfully synthesized. As high as 58% DOX and 6% Ce6 by weight could be loaded onto the HAuNs-p(OEGMA-co-MEMA) nanocomposites. The grafting polymer brushes outside the HAuNs play the role of ``gate molecules'' for controlled drug release by 650 nm laser radiation owing to the temperature-sensitive property of the polymer and the photothermal effect of HAuNs. The HAuNs-p(OEGMA-co-MEMA)-Ce6-DOX nanocomposites with 650 nm laser radiation show effective inhibition of cancer cells in vitro and enhanced anti-tumor efficacy in vivo. In contrast, control groups without laser radiation show little cytotoxicity. The nanocomposite demonstrates a way of ``killing three birds with one stone'', that is, chemotherapy, photothermal and photodynamic therapy are triggered simultaneously by the 650 nm laser stimulation. Therefore, the nanocomposites show the great advantages of multi-modal synergistic effects for cancer therapy by a remote-controlled laser stimulus.Combining multi-model treatments within one single system has attracted great interest for the purpose of synergistic therapy. In this paper, hollow gold nanospheres (HAuNs) coated with a temperature-sensitive polymer, poly(oligo(ethylene oxide) methacrylate-co-2-(2-methoxyethoxy)ethyl methacrylate) (p(OEGMA-co-MEMA)), co-loaded with DOX and a photosensitizer Chlorin e6 (Ce6) were successfully synthesized. As high as 58% DOX and 6% Ce6 by weight could be loaded onto the HAuNs-p(OEGMA-co-MEMA) nanocomposites. The grafting polymer brushes outside the HAuNs play the role of ``gate molecules'' for controlled drug release by 650 nm laser radiation

Effects of enhanced UV-B radiation on Mentha spicata essential oils

International Nuclear Information System (INIS)

Karousou, R.; Grammatikopoulos, G.; Lanaras, T.; Manetas, Y.; Kokkini, S.

1998-01-01

In vitro propagated plantlets representing two distinct chemotypes of Mentha spicata, viz. plants producing essential oils rich in piperitone oxide and piperitenone oxide (chemotype I) and rich in carvone and dihydrocarvone (chemotype II), were grown in the field under ambient or ambient plus supplemental UV-B radiation, biologically equivalent to a 15% ozone depletion over Patras (38.3°N, 29.1°E), Greece. Enhanced UV-B radiation stimulated essential oil production in chemotype II substantially, while a similar, non-significant trend was observed in chemotype I. No effect was found on the qualitative composition of the essential oils, whereas the quantitative composition was slightly modified in chemotype I. This is the first investigation reporting an improved essential oil content under UV-B supplementation in aromatic plants under field conditions

Trans-generational radiation-induced chromosomal instability in the female enhances the action of chemical mutagens

International Nuclear Information System (INIS)

Camats, Nuria; Garcia, Francisca; Parrilla, Juan Jose; Calaf, Joaquim; Martin, Miguel; Caldes, Montserrat Garcia

2008-01-01

Genomic instability can be produced by ionising radiation, so-called radiation-induced genomic instability, and chemical mutagens. Radiation-induced genomic instability occurs in both germinal and somatic cells and also in the offspring of irradiated individuals, and it is characterised by genetic changes including chromosomal rearrangements. The majority of studies of trans-generational, radiation-induced genomic instability have been described in the male germ line, whereas the authors who have chosen the female as a model are scarce. The aim of this work is to find out the radiation-induced effects in the foetal offspring of X-ray-treated female rats and, at the same time, the possible impact of this radiation-induced genomic instability on the action of a chemical mutagen. In order to achieve both goals, the quantity and quality of chromosomal damage were analysed. In order to detect trans-generational genomic instability, a total of 4806 metaphases from foetal tissues from the foetal offspring of X-irradiated female rats (5 Gy, acute dose) were analysed. The study's results showed that there is radiation-induced genomic instability: the number of aberrant metaphases and the breaks per total metaphases studied increased and were found to be statistically significant (p ≤ 0.05), with regard to the control group. In order to identify how this trans-generational, radiation-induced chromosomal instability could influence the chromosomal behaviour of the offspring of irradiated rat females in front of a chemical agent (aphidicolin), a total of 2481 metaphases were studied. The observed results showed that there is an enhancement of the action of the chemical agent: chromosomal breaks per aberrant metaphases show significant differences (p ≤ 0.05) in the X-ray- and aphidicolin-treated group as regards the aphidicolin-treated group. In conclusion, our findings indicate that there is trans-generational, radiation-induced chromosomal instability in the foetal cells

Trans-generational radiation-induced chromosomal instability in the female enhances the action of chemical mutagens

Energy Technology Data Exchange (ETDEWEB)

Camats, Nuria [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Garcia, Francisca [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Parrilla, Juan Jose [Servicio de Ginecologia y Obstetricia, Hospital Universitario Virgen de la Arrixaca, 30120 El Palmar, Murcia (Spain); Calaf, Joaquim [Servei de Ginecologia i Obstetricia, Hospital Universitari de la Santa Creu i Sant Pau, 08025 Barcelona (Spain); Martin, Miguel [Departament de Pediatria, d' Obstetricia i Ginecologia i de Medicina Preventiva, Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Caldes, Montserrat Garcia [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Barcelona (Spain)], E-mail: Montserrat.Garcia.Caldes@uab.es

2008-04-02

Genomic instability can be produced by ionising radiation, so-called radiation-induced genomic instability, and chemical mutagens. Radiation-induced genomic instability occurs in both germinal and somatic cells and also in the offspring of irradiated individuals, and it is characterised by genetic changes including chromosomal rearrangements. The majority of studies of trans-generational, radiation-induced genomic instability have been described in the male germ line, whereas the authors who have chosen the female as a model are scarce. The aim of this work is to find out the radiation-induced effects in the foetal offspring of X-ray-treated female rats and, at the same time, the possible impact of this radiation-induced genomic instability on the action of a chemical mutagen. In order to achieve both goals, the quantity and quality of chromosomal damage were analysed. In order to detect trans-generational genomic instability, a total of 4806 metaphases from foetal tissues from the foetal offspring of X-irradiated female rats (5 Gy, acute dose) were analysed. The study's results showed that there is radiation-induced genomic instability: the number of aberrant metaphases and the breaks per total metaphases studied increased and were found to be statistically significant (p {<=} 0.05), with regard to the control group. In order to identify how this trans-generational, radiation-induced chromosomal instability could influence the chromosomal behaviour of the offspring of irradiated rat females in front of a chemical agent (aphidicolin), a total of 2481 metaphases were studied. The observed results showed that there is an enhancement of the action of the chemical agent: chromosomal breaks per aberrant metaphases show significant differences (p {<=} 0.05) in the X-ray- and aphidicolin-treated group as regards the aphidicolin-treated group. In conclusion, our findings indicate that there is trans-generational, radiation-induced chromosomal instability in the foetal

Enhancement of ZnO-rGO nanocomposite thin films by gamma radiation for E. coli sensor

Energy Technology Data Exchange (ETDEWEB)

Noor Azmy, Noor Azwen [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, 43650, UKM, Bangi, Selangor (Malaysia); Bakar, Ahmad Ashrif A., E-mail: ashrif@ukm.edu.my [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, 43650, UKM, Bangi, Selangor (Malaysia); Arsad, Norhana [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, 43650, UKM, Bangi, Selangor (Malaysia); Idris, Sarada [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, 43650, UKM, Bangi, Selangor (Malaysia); Radiation Facilities Division, Block 42, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Mohmad, Abdul Rahman [MEMS-NEMS and Nanoelectronics, Institute of Microengineering and Nanoelectronics (IMEN), 43650 UKM, Bangi, Selangor (Malaysia); Abdul Hamid, Aidil [School of Biosciences and Biotechnology, Faculty of Science and Technology, 43650 UKM, Bangi, Selangor (Malaysia)

2017-01-15

Highlights: • ZnO-rGO nanocomposite thin films by gamma radiation for E. coli sensor were fabricated for the first time. • Exposed to gamma radiation leads to the change the microstructure of the films. • The optical behaviors of thin films were found to be gamma dose dependent. • The sensors had a linear response with GO concentration. • The sensors exhibited enhanced sensitivity at higher gamma radiation. - Abstract: The fabricated E. coli sensor of ZnO-rGO nanocomposite thin films by gamma radiation was investigated. Nanocomposite films were prepared via sol–gel method and were irradiated at 10 kGy at room temperature. The surface characteristic of as-prepared samples have been characterized by x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The proposed structure shows that exposed gamma radiation may change the microstructure of the films occurs as a result of their flexible structure. Uv–vis spectra of nanocomposite were studied to investigate the optical behavior of ZnO-rGO films and the optical energy band gap and Urbach energy were found to be gamma dose dependent. The sensing properties were identified by measuring the changes of conductivity of film using I-V measurement. Upon exposure to E. coli, the radiated ZnO-rGO films (1.00 vol% GO) exhibited higher sensitivity, as much as 4.62 × 10{sup −3}, than un-radiated films, 1.04 × 10{sup −3}. This enhancement of the I-V response was attributed to a positive influence of the gamma radiation in these films. The results prove that our ZnO-rGO nanocomposites thin films by gamma radiation demonstrate a strong performance for the detection of microbiological organisms in water.

Combination Therapy with NHS-muIL12 and Avelumab (anti-PD-L1) Enhances Antitumor Efficacy in Preclinical Cancer Models.

Science.gov (United States)

Xu, Chunxiao; Zhang, Yanping; Rolfe, P Alexander; Hernández, Vivian M; Guzman, Wilson; Kradjian, Giorgio; Marelli, Bo; Qin, Guozhong; Qi, Jin; Wang, Hong; Yu, Huakui; Tighe, Robert; Lo, Kin-Ming; English, Jessie M; Radvanyi, Laszlo; Lan, Yan

2017-10-01

Purpose: To determine whether combination therapy with NHS-muIL12 and the anti-programmed death ligand 1 (PD-L1) antibody avelumab can enhance antitumor efficacy in preclinical models relative to monotherapies. Experimental Design: BALB/c mice bearing orthotopic EMT-6 mammary tumors and μMt - mice bearing subcutaneous MC38 tumors were treated with NHS-muIL12, avelumab, or combination therapy; tumor growth and survival were assessed. Tumor recurrence following remission and rechallenge was evaluated in EMT-6 tumor-bearing mice. Immune cell populations within spleen and tumors were evaluated by FACS and IHC. Immune gene expression in tumor tissue was profiled by NanoString® assay and plasma cytokine levels were determined by multiplex cytokine assay. The frequency of tumor antigen-reactive IFNγ-producing CD8 + T cells was evaluated by ELISpot assay. Results: NHS-muIL12 and avelumab combination therapy enhanced antitumor efficacy relative to either monotherapy in both tumor models. Most EMT-6 tumor-bearing mice treated with combination therapy had complete tumor regression. Combination therapy also induced the generation of tumor-specific immune memory, as demonstrated by protection against tumor rechallenge and induction of effector and memory T cells. Combination therapy enhanced cytotoxic NK and CD8 + T-cell proliferation and T-bet expression, whereas NHS-muIL12 monotherapy induced CD8 + T-cell infiltration into the tumor. Combination therapy also enhanced plasma cytokine levels and stimulated expression of a greater number of innate and adaptive immune genes compared with either monotherapy. Conclusions: These data indicate that combination therapy with NHS-muIL12 and avelumab increased antitumor efficacy in preclinical models, and suggest that combining NHS-IL12 and avelumab may be a promising approach to treating patients with solid tumors. Clin Cancer Res; 23(19); 5869-80. ©2017 AACR . ©2017 American Association for Cancer Research.

Heat transfer enhancement of Al_2O_3-EG nanofluid in a car radiator with wire coil inserts

International Nuclear Information System (INIS)

Goudarzi, K.; Jamali, H.

2017-01-01

Highlights: • The purpose of this paper is heat transfer enhancement in a car radiator. • The simultaneous impacts of nanofluid EG/Al_2O_3 with wire coil inserts are studied. • Results show that the thermal performance enhancement up to 14%. • With increasing speed of cooling fan, Nusselt number at Reynolds numbers increased. - Abstract: In this experimental study, Aluminums Oxide (Al_2O_3) in Ethylene Glycol (EG) as nanofluid was used for heat transfer enhancement in car radiator together with wire coil inserts. Two wire coils inserts with different geometry and nanofluids with volume concentrations of 0.08%, 0.5% and 1% were investigated. The results indicated that the use of coils inserts enhanced heat transfer rates up to 9%. In addition, the simultaneous use of the coils inserts with the nanofluid with concentration of 0.08%, 0.5% and 1% resulted the thermal performance enhancement up to 5% as compared to the use of coils inserts alone.

Intergranular attack observed in radiation-enhanced corrosion of mild steel

International Nuclear Information System (INIS)

Reda, R.J.; Kelly, J.L.; Harna, S.L.A.

1988-01-01

Experiments were conducted to determine the effects of gamma radiation on the corrosion of AISI 1018 mild steel in deaerated brine solutions of various sodium, magnesium, and chloride ion concentrations. Immersed metal specimens were irradiated at an exposure rate of 3 x 10/sup 5/ R/h (0.3 MR/h) for up to 1250 h at a temperature of --25 C. The corrosion rates of the irradiated specimens were found to be roughly a factor of 10 greater than the rates for the non-irradiated specimens. The radiation-enhanced corrosion rate was also found to have increased with the chloride concentration. Electron micrographs revealed that the surface morphology of the specimens exposed to irradiated brines differed greatly from the non-irradiated specimens. The non-irradiated specimens had undergone uniform corrosion, while the irradiated specimens exhibited intergranular corrosion (IGC), a phenomenon not yet observed in mild steel. An explanation for this observation is offered in terms of the relative rates of formation and recombination of radiolytic species

Leaf anatomical changes in Populus trichocarpa, Quercus rubra, Pseudotsuga menziesii and Pinus ponderosa exposed to enhanced ultraviolet-B radiation

International Nuclear Information System (INIS)

Nagel, L.M.; Bassman, J.H.; Edwards, G.E.; Robberecht, R.; Franceshi, V.R.

1998-01-01

Leaf anatomical characteristics are important in determining the degree of injury sustained when plants are exposed to natural and enhanced levels of ultraviolet-B (UV-B) radiation (280–320 nm). The degree to which leaf anatomy can adapt to the increasing levels of UV-B radiation reaching the earth's surface is poorly understood in most tree species. We examined four tree species, representing a wide range of leaf anatomical characteristics, to determine responses of leaf area, specific leaf weight, and leaf tissue parameters after exposure to ambient and enhanced levels of UV-B radiation. Seedlings were grown in a greenhouse with photosynthetically active radiation of 39 mol m −2 day −1 and under one of three daily irradiances of biologically effective UV-B radiation (UV-BBE) supplied for 10 h per day: (1) approximate ambient level received at Pullman, Washington on June 21 (1 x ); two times ambient (2 x ), or three times ambient (3 x ). We hypothesized the response of each species to UV-B radiation would be related to inherent anatomical differences. We found that the conifers responded anatomically to nearly an equal degree as the broad-leaved trees, but that different tissues were involved. Populus trichocarpa, an indeterminate broadleaf species, showed significantly thicker palisade parenchyma in recently mature leaves at the 3 x level and in older leaves under the 2 x level. In addition, individual leaf area was generally greater with increased UV-B irradiance. Quercus rubra, a semi-determinate broadleaf species, exhibited significantly thicker palisade parenchyma at the 2 x and 3 x levels as compared to controls. Psuedotsuga menziesii, an evergreen coniferous species with bifacially flattened needles, and Pinus ponderosa, an evergreen coniferous species with a complete hypodermis, showed no significant change in leaf area or specific leaf weight under enhanced UV-B radiation. Epidermal thickness was unchanged in P. menziesii. However, P. ponderosa

Efficacy of liver parenchymal enhancement and liver volume to standard liver volume ratio on Gd-EOB-DTPA-enhanced MRI for estimation of liver function

Energy Technology Data Exchange (ETDEWEB)

Yoneyama, Tomohide; Fukukura, Yoshihiko; Kamimura, Kiyohisa; Takumi, Koji; Umanodan, Aya; Nakajo, Masayuki [Kagoshima University Graduate School of Medical and Dental Sciences, Department of Radiology, Kagoshima City (Japan); Ueno, Shinichi [Kagoshima University Graduate School of Medical and Dental Sciences, Department of Surgical Oncology and Digestive Surgery, Kagoshima City (Japan)

2014-04-15

We aimed to develop and assess the efficacy of a liver function index that combines liver enhancement and liver volume to standard liver volume (LV/SLV) ratio on gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI. In all, 111 patients underwent a Gd-EOB-DTPA-enhanced MRI, including T1 mapping, before and 20 min after Gd-EOB-DTPA administration. We calculated the following Gd-EOB-DTPA-enhanced MRI-based liver function indices: relative enhancement of the liver, corrected enhancement of the liver-to-spleen ratio, LSC{sub N}20, increase rate of the liver-to-muscle ratio, reduction rate of T1 relaxation time of the liver, ΔR1 of the liver and K{sub Hep}; the indices were multiplied by the LV/SLV ratio. We calculated the correlations between an indocyanine green (ICG) clearance and the Gd-EOB-DTPA-enhanced MRI-based liver function indices multiplied by the LV/SLV ratio, by using Pearson correlation analysis. There were significant correlations between all Gd-EOB-DTPA-enhanced MRI-based liver function indices and ICG clearance (r = -0.354 to -0.574, P < 0.001). All Gd-EOB-DTPA-enhanced MRI-based liver function indices multiplied by the LV/SLV ratio (r = -0.394 to -0.700, P < 0.001) were more strongly correlated with the ICG clearance than those without multiplication by the LV/SLV ratio. Gd-EOB-DTPA-enhanced MRI-based liver function indices that combine liver enhancement and the LV/SLV ratio may more reliably estimate liver function. (orig.)

Comparative Efficacy of Aloe vera and Benzydamine Mouthwashes on Radiation-induced Oral Mucositis: A Triple-blind, Randomised, Controlled Clinical Trial.

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Sahebjamee, Mahnaz; Mansourian, Arash; Hajimirzamohammad, Mohammad; Mohammad, Haji Mirza Mohammad; Zadeh, Mohsen Taghi; Bekhradi, Reza; Kazemian, Ali; Manifar, Soheila; Ashnagar, Sajjad; Doroudgar, Kiavash

2015-01-01

To compare the efficacy of an Aloe vera mouthwash with a benzydamine mouthwash in the alleviation of radiation- induced mucositis in head and neck cancer patients using a triple-blind, randomised controlled trial. Twenty-six eligible head and neck cancer patients who were to receive conventional radiation therapy at the radiation oncology department were randomised to receive an Aloe vera mouthwash or a benzydamine mouthwash. Mucositis severity was assessed during the course of radiation therapy using the WHO grading system. At baseline, there was no difference in the distribution of mucositis severity between the two groups. The mean interval between radiation therapy and onset of mucositis was similar for both groups (Aloe vera 15.69±7.77 days, benzydamine 15.85±12.96 days). The mean interval between the start of radiation therapy and the maximum severity of mucositis were was also similar in both the Aloe vera and benzydamine groups (Aloe vera 23.38±10.75 days, benzydamine 23.54±15.45 days). Mean changes of mucositis severity over time in both groups were statistically similar and the effect of both treatments did not change signficantly with time (p=0.09). Aloe vera mouthwash was as beneficial as benzydamine mouthwash in alleviating the severity of radiation-induced mucositis and showed no side effects. The Aloe vera mouthwash could be an alternative agent in the treatment of radiation-induced mucositis in patients with head and neck cancers.

Effect of Photon Beam Energy, Gold Nanoparticle Size and Concentration on the Dose Enhancement in Radiation Therapy

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Nahideh Gharehaghaji

2013-02-01

Full Text Available Introduction: Gold nanoparticles have been used as radiation dose enhancing materials in recent investigations. In the current study, dose enhancement effect of gold nanoparticles on tumor cells was evaluated using Monte Carlo (MC simulation. Methods: We used MCNPX code for MC modeling in the current study. A water phantom and a tumor region with a size of 1×1×1 cm3 loaded with gold nanoparticles were simulated. The macroscopic dose enhancement factor was calculated for gold nanoparticles with sizes of 30, 50, and 100 nm. Also, we simulated different photon beams including mono-energetic beams (50-120 keV, a Cobalt-60 beam, 6 & 18 MV photon beams of a conventional linear accelerator. Results: We found a dose enhancement factor (DEF of from 1.4 to 3.7 for monoenergetic kilovoltage beams, while the DEFs for megavoltage beams were negligible and less than 3% for all GNP sizes and concentrations. The optimum energy for higher DEF was found to be the 90 keV monoenergetic beam. The effect of GNP size was not considerable, but the GNP concentration had a substantial impact on achieved DEF in GNP-based radiation therapy. Conclusion: The results were in close agreement with some previous studies considering the effect of photon energy and GNP concentration on observed DEF. Application of GNP-based radiation therapy using kilovoltage beams is recommended.

In vivo demonstration of enhanced radiotherapy using rare earth doped titania nanoparticles.

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Townley, Helen E; Kim, Jeewon; Dobson, Peter J

2012-08-21

Radiation therapy is often limited by damage to healthy tissue and associated side-effects; restricting radiation to ineffective doses. Preferential incorporation of materials into tumour tissue can enhance the effect of radiation. Titania has precedent for use in photodynamic therapy (PDT), generating reactive oxygen species (ROS) upon photoexcitation, but is limited by the penetration depth of UV light. Optimization of a nanomaterial for interaction with X-rays could be used for deep tumour treatment. As such, titania nanoparticles were doped with gadolinium to optimize the localized energy absorption from a conventional medical X-ray, and further optimized by the addition of other rare earth (RE) elements. These elements were selected due to their large X-ray photon interaction cross-section, and potential for integration into the titania crystal structure. Specific activation of the nanoparticles by X-ray can result in generation of ROS leading to cell death in a tumour-localized manner. We show here that intratumoural injection of RE doped titania nanoparticles can enhance the efficacy of radiotherapy in vivo.

Enhanced radiation resistance through interface modification of nano-structured steels for Gen IV in-core applications

International Nuclear Information System (INIS)

Jang, Jinsung; Kang, Suk Hoon; Kim, Min Chul

2013-06-01

This project is to increase radiation tolerance of candidate alloys for Gen IV core component through the optimization of grain size and grain boundary characteristics. The focus is on nanocrystalline metal alloys with a fcc crystal structure. The long-term goal is to design and develop bulk nanostructured austenitic steels with enhanced void swelling resistance and substantial ductility, and to enhance their creep resistance at elevated temperatures via grain boundary engineering. An austenitic stainless steel, HT-UPS (high temperature ultra-fine precipitates strengthened) was developed at ORNL, and is expected to show enhanced void swelling resistance through the trapping of point defects at nanometer-sized carbides. Reducing the grain size and increasing the fraction-induced point defects (due to the increased sink area of the grain boundaries), to make bubble nucleation at the boundaries less likely (by reducing the fraction of high-energy boundaries), and to improve the strength and ductility under radiation by producing a higher density of nanometer sized carbides on the boundaries

Radiation Characteristics Enhancement of Dielectric Resonator Antenna Using Solid/Discrete Dielectric Lenses

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H. A. E. Malhat

2015-02-01

Full Text Available The radiation characteristics of the dielectric resonator antennas (DRA is enhanced using different types of solid and discrete dielectric lenses. One of these approaches is by loading the DRA with planar superstrate, spherical lens, or by discrete lens (transmitarray. The dimensions and dielectric constant of each lens are optimized to maximize the gain of the DRA. A comparison between the radiations characteristics of the DRA loaded with different lenses are introduced. The design of the dielectric transmitarray depends on optimizing the heights of the dielectric material of the unit cell. The optimized transmitarray achieves 7 dBi extra gain over the single DRA with preserving the circular polarization. The proposed antenna is suitable for various applications that need high gain and focused antenna beam.

Disruption of Circadian rhythms enhances radiation tolerance in mice

International Nuclear Information System (INIS)

Patil, Shrikant L.; Krishna, A.P.; Somashekarappa, H.M.; Patil, Rajashekar K.

2014-01-01

Whether an alteration in responses to the radiations depends on the phase of Circadian rhythm, this has been explored previously. The results however have been inconclusive and only survival rate of animals has been considered to represent the effect. Circadian phase has been shown to be critical in many therapeutic procedures. The present study was conducted on control group of mice (12L: 12D), extended day length and night length by imposing 24 hrs of light followed by 24 hrs of darkness, a third group received (8L: 8D) light: day cycles. These regimes were operational for seven days, at the end of seventh day mice from three different groups were exposed to 3 Gy of total body gamma radiation. Survival study, extent of lipid peroxidation and antioxidant status was estimated. Radioresistance was found to be enhanced in mice maintained at 8L: 8D cycle. There was no significant changes observed in mice of time shift group (24L: 24D). The corresponding shift in the acrophase of radioresistance following a sudden time shift supports the effect of disrupted circadian rhythms. (author)

Biofilm disruption with rotating microrods enhances antimicrobial efficacy

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Mair, Lamar O.; Nacev, Aleksandar; Hilaman, Ryan; Stepanov, Pavel Y.; Chowdhury, Sagar; Jafari, Sahar; Hausfeld, Jeffrey; Karlsson, Amy J.; Shirtliff, Mark E.; Shapiro, Benjamin; Weinberg, Irving N.

2017-04-01

Biofilms are a common and persistent cause of numerous illnesses. Compared to planktonic microbes, biofilm residing cells often demonstrate significant resistance to antimicrobial agents. Thus, methods for dislodging cells from the biofilm may increase the antimicrobial susceptibility of such cells, and serve as a mechanical means of increasing antimicrobial efficacy. Using Aspergillus fumigatus as a model microbe, we magnetically rotate microrods in and around biofilm. We show that such rods can improve the efficacy of antimicrobial Amphotericin B treatments in vitro. This work represents a first step in using kinetic magnetic particle therapy for disrupting fungal biofilms.

Use of radiation hygienised municipal sewage sludge as a soil conditioner to enhance agricultural productivity

International Nuclear Information System (INIS)

Shah, M.R.; Nareshkumar; Sabharwal, S.

2009-01-01

This paper presents a report on the applications that have been developed and demonstrated in the radiation hygienisation of municipal sewage sludge for use in the agriculture as value added manure. Radiation hygienization process effectively eliminates the pathogenic bacteria present in the sewage sludge. Application of sludge to agricultural land enhances the yield and quality of agricultural products due to macronutrients and micronutrients present in the sludge. The process benefits municipal sewage treatment plant authorities as well as farming community. (author)

The enhancement of natural radiation dosage by coal-fired power generation in the United Kingdom

International Nuclear Information System (INIS)

Corbett, J.O.

1980-02-01

The total fuel cycle of electricity generation from coal is assessed as a source of enhanced exposure to natural radiation. The various routes by which such exposure can arise are discussed and the consequent individual and collective radiation doses in the United Kingdom are estimated on the basis of a critical review of published data augmented by the results of recent, hitherto unpublished work within the CEGB. Further work is in progress to clarify particular areas of uncertainty that have been identified. (author)

Preparation and physical properties of enhanced radiation induced crosslinking of ethylene-vinyl alcohol copolymer (EVOH)

International Nuclear Information System (INIS)

Deng Pengyang; Liu Meihua; Zhang Wanxi; Sun Jiazhen

2007-01-01

Preparation and physical properties of ethylene-vinyl alcohol copolymer (EVOH) crosslinked by enhanced radiation have been studied through various methods. It was found that the most effective agent for irradiation-crosslinking was triallyl isocyanurate (TAIC) among four kinds of polyfunctional monomers. Gel content (65.6%) was formed for EVOH-44 (content of ethylene is 44 mol%) at 200 kGy with 5% TAIC, but for EVOH-32 (content of ethylene is 32 mol%), only 37.4% gel content was formed under the same conditions. This result showed that the more the content of ethylene units comprised in EVOH, the easier the chemical bonds could be formed between different molecular chains. Tensile strength and elastic modulus increased after crosslinking at high test temperature and elongation at break decreased at the same time. Hygroscopicity of EVOH showed noticeable decrease after enhancement radiation-crosslinking

Anticancer Drug-Incorporated Layered Double Hydroxide Nanohybrids and Their Enhanced Anticancer Therapeutic Efficacy in Combination Cancer Treatment

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Tae-Hyun Kim

2014-01-01

Full Text Available Objective. Layered double hydroxide (LDH nanoparticles have been studied as cellular delivery carriers for anionic anticancer agents. As MTX and 5-FU are clinically utilized anticancer drugs in combination therapy, we aimed to enhance the therapeutic performance with the help of LDH nanoparticles. Method. Anticancer drugs, MTX and 5-FU, and their combination, were incorporated into LDH by reconstruction method. Simply, LDHs were thermally pretreated at 400°C, and then reacted with drug solution to simultaneously form drug-incorporated LDH. Thus prepared MTX/LDH (ML, 5-FU/LDH (FL, and (MTX + 5-FU/LDH (MFL nanohybrids were characterized by X-ray diffractometer, scanning electron microscopy, infrared spectroscopy, thermal analysis, zeta potential measurement, dynamic light scattering, and so forth. The nanohybrids were administrated to the human cervical adenocarcinoma, HeLa cells, in concentration-dependent manner, comparing with drug itself to verify the enhanced therapeutic efficacy. Conclusion. All the nanohybrids successfully accommodated intended drug molecules in their house-of-card-like structures during reconstruction reaction. It was found that the anticancer efficacy of MFL nanohybrid was higher than other nanohybrids, free drugs, or their mixtures, which means the multidrug-incorporated LDH nanohybrids could be potential drug delivery carriers for efficient cancer treatment via combination therapy.

Drug Repositioning of Proton Pump Inhibitors for Enhanced Efficacy and Safety of Cancer Chemotherapy

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Kenji Ikemura

2017-12-01

Full Text Available Proton pump inhibitors (PPIs, H+/K+-ATPase inhibitors, are the most commonly prescribed drugs for the treatment of gastroesophageal reflux and peptic ulcer diseases; they are highly safe and tolerable. Since PPIs are frequently used in cancer patients, studies investigating interactions between PPIs and anticancer agents are of particular importance to achieving effective and safe cancer chemotherapy. Several studies have revealed that PPIs inhibit not only the H+/K+-ATPase in gastric parietal cells, but also the vacuolar H+-ATPase (V-ATPase overexpressed in tumor cells, as well as the renal basolateral organic cation transporter 2 (OCT2 associated with pharmacokinetics and/or renal accumulation of various drugs, including anticancer agents. In this mini-review, we summarize the current knowledge regarding the impact of PPIs on the efficacy and safety of cancer chemotherapeutics via inhibition of targets other than the H+/K+-ATPase. Co-administration of clinical doses of PPIs protected kidney function in patients receiving cisplatin and fluorouracil, presumably by decreasing accumulation of cisplatin in the kidney via OCT2 inhibition. In addition, co-administration or pretreatment with PPIs could inhibit H+ transport via the V-ATPase in tumor cells, resulting in lower extracellular acidification and intracellular acidic vesicles to enhance the sensitivity of the tumor cells to the anticancer agents. In the present mini-review, we suggest that PPIs enhance the efficacy and safety of anticancer agents via off-target inhibition (e.g., of OCT2 and V-ATPase, rather than on-target inhibition of the H+/K+-ATPase. The present findings should provide important information to establish novel supportive therapy with PPIs during cancer chemotherapy.

Lactobionic acid-conjugated TPGS nanoparticles for enhancing therapeutic efficacy of etoposide against hepatocellular carcinoma

Science.gov (United States)

Tsend-Ayush, Altansukh; Zhu, Xiumei; Ding, Yu; Yao, Jianxu; Yin, Lifang; Zhou, Jianping; Yao, Jing

2017-05-01

Many effective anti-cancer drugs have limited use in hepatocellular carcinoma (HCC) therapy due to the drug resistance mechanisms in liver cells. In recent years, tumor-targeted drug delivery and the inhibition of drug-resistance-related mechanisms has become an integrated strategy for effectively combating chemo-resistant cancer. Herein, lactobionic acid-conjugated d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS-LA conjugate) has been developed as a potential asialoglycoprotein receptor (ASGPR)-targeted nanocarrier and an efficient inhibitor of P-glycoprotein (P-gp) to enhance etoposide (ETO) efficacy against HCC. The main properties of ETO-loaded TPGS-LA nanoparticles (NPs) were tested through in vitro and in vivo studies after being prepared using the nanoprecipitation method and characterized by dynamic light scattering (DLS). According to the results, smaller (˜141.43 nm), positively charged ETO-loaded TPGS-LA NPs were more suitable for providing efficient delivery to hepatoma cells by avoiding the clearance mechanisms. It was found that ETO-loaded TPGS-LA NPs were noticeably able to enhance the cytotoxicity of ETO in HepG2 cells. Besides this, markedly higher internalization by the ASGPR-overexpressed HepG2 cells and efficient accumulation at the tumor site in vivo were revealed in the TPGS-LA NP group. More importantly, animal studies confirmed that ETO-loaded TPGS-LA NPs achieved the highest therapeutic efficacy against HCC. Interestingly, ETO-loaded TPGS-LA NPs also exhibited a great inhibitory effect on P-gp compared to the ETO-loaded TPGS NPs. These results suggest that TPGS-LA NPs could be used as a potential ETO delivery system against HCC.

Changes in Science Teaching Self-Efficacy among Primary Teacher Education Students

Science.gov (United States)

Palmer, David; Dixon, Jeanette; Archer, Jennifer

2015-01-01

Many preservice primary teachers have low self-efficacy for science teaching. Although science methods courses have often been shown to enhance self-efficacy, science content courses have been relatively ineffective in this respect. This study investigated whether a tailored science content course would enhance self-efficacy. The participants were…

Radiation therapy for operable rectal cancer

International Nuclear Information System (INIS)

Bondar, G.V.; Semikoz, N.G.; Bashejev, V.Kh.; Borota, O.V.; Bondarenko, M.V.; Kiyashko, O.Yu.

2012-01-01

The authors present a review of the literature on modern tendencies of radiation therapy application to treatment of operable rectal cancer. Many randomized control studies compared the efficacy of combination of radiation therapy (pre-operative or post-operative) and surgery versus surgery only demonstrating various results. Meta-analysis of the data on efficacy of combination of radiation therapy and standard surgery revealed 22 randomized control studies (14 with pre-operative radiation therapy and 8 with post-operative radiation therapy) with total number of 8507 patients (Colorectal Cancer Collaborative Group, 2000). The use of combination treatment reduced the number of isolated locoregional relapses both with pre-operative (22.5 - 12.5 %; p < 0.00001) and post-operative radiation therapy (25.8 - 16.7 %; p - 0.00001). The influence on total survival was not significant (62 % vs. 63 %; p - 0.06).

Effects of sulekang capsule in enhancement of resistance to radiation and regulating immunological function in mice

International Nuclear Information System (INIS)

Zhao Naikun; Zhou Ouliang; Du Weixia

1990-01-01

The effects of Sulekang capsule in enhancing the resistance to radiation and regulating the immunological function in mice were described. The results show that Sulekang capsule may lengthen the survival time (p 60 Co gamma rays. The experimental results of ANAE reaction show that the activety of T cells of normal or exposed mice may be enhanced by Sulekang capsule, which can control the decrease of both ANAE-positive cells and T cells in exposed mice. So it may enhance the immunological function on exposed animals

Enhancing Cross-Cultural Training Efficacy on Expatriate Adjustment through Emotional Intelligence and Social Capital

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Ely Susanto

2012-05-01

Full Text Available Cross cultural training is widely believed to make a positive contribution to expatriate adjustment. In practice, however, it is very costly and sometimes ineffective for expatriates. Therefore, there is a growing importance placed on increasing the cost effectiveness or enhancing the efficacy of crosscultural training by functioning individual expatriate’s social capital and emotional intelligence as moderating variables towards expatriate’s adjustment and performance. To do so we blend ideas drawn from social capital theory and emotional intelligence to develop the structure that underlies the logic of this paper. Thus, this paper uses social capital and emotional intelligence theories to enrich extant literature on expatriate adjustment

Influence of Gamma Radiation on the Treatment of Sulfate Reducing Bacteria in the Injection Water Used for the Enhanced Oil Recovery

International Nuclear Information System (INIS)

El-Shahawy, M.R.; Ramzi, M.; Farag, R.M.

2014-01-01

The counts of sulfate reducing bacteria (SRB) in the water samples collected from the well head (formation water) and outlet of petroleum treatment plant (Produced water) in a petroleum field in middle delta- Egypt were determined. The data showed a low count of (SRB) in the collected formation water sample and there was an obvious increase in the bacterial counts which appeared in the produced water, that may reveal that the presence of appropriate conditions for the growth of (SRB) in the closed system in treatment plant. Two scale inhibitors were tested through jar test, the scale inhibitor I had maximum efficiency at 20 ppm, two SRB biocides were screened for their bactericidal activities. It was found that the biocides A was slightly superior in respect to the antibacterial efficacy compared to B in presence of 20 ppm scale inhibitor. These biocides were test for the study of the combined treatment with gamma radiation to maximize the efficiency on sulfate reducing bacteria using the minimum effective dose of both radiation and biocides to eliminate the negative impacts of the chemicals used and the radiation applied. The results demonstrated that, the lethal doses of biocides were (300 ppm) of biocides A or (400 ppm) of biocides B at 1 kGy irradiation dose. The treated produced water was evaluated in respect of enhanced oil recovery, the data showed increase of the recovery capacity by the irradiation and chemical treatment. This technology could be used for the water that are injected into reservoirs, and suitable for oil field and pipeline operators, and presented a viable bacteria control method

Ultraviolet germicidal efficacy as a function of pulsed radiation parameters studied by spore film dosimetry.

Science.gov (United States)

Bauer, Stefan; Holtschmidt, Hans; Ott, Günter

2018-01-01

Disinfection by pulsed ultraviolet (UV) radiation is a commonly used method, e.g. in industry or medicine and can be carried out either with lasers or broadband UV radiation sources. Detrimental effects to biological materials depending on parameters such as pulse duration τ or pulse repetition frequency f p are well-understood for pulsed coherent UV radiation, however, relatively little is known for its incoherent variant. Therefore, within this work, it is the first time that disinfection rates of pulsed and continuous (cw) incoherent UV radiation studied by means of spore film dosimetry are presented, compared with each other, and in a second step further investigated regarding two pulse parameters. After analyzing the dynamic range of the Bacillus subtilis spore films with variable cw radiant exposures H=5-100Jm -2 a validation of the Bunsen-Roscoe law revealed its restricted applicability and a 28% enhanced detrimental effect of pulsed compared to cw incoherent UV radiation. A radiant exposure H=50Jm -2 and an irradiance E=0.5Wm -2 were found to be suitable parameters for an analysis of the disinfection rate as a function of τ=0.5-10ms and f p =25-500Hz unveiling that shorter pulses and lower frequencies inactivate more spores. Finally, the number of applied pulses as well as the experiment time were considered with regard to spore film disinfection. Copyright © 2017 Elsevier B.V. All rights reserved.

Augmenting the Efficacy of Immunotoxins and Other Targeted Protein Toxins by Endosomal Escape Enhancers

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Hendrik Fuchs

2016-07-01

Full Text Available The toxic moiety of almost all protein-based targeted toxins must enter the cytosol of the target cell to mediate its fatal effect. Although more than 500 targeted toxins have been investigated in the past decades, no antibody-targeted protein toxin has been approved for tumor therapeutic applications by the authorities to date. Missing efficacy can be attributed in many cases to insufficient endosomal escape and therefore subsequent lysosomal degradation of the endocytosed toxins. To overcome this drawback, many strategies have been described to weaken the membrane integrity of endosomes. This comprises the use of lysosomotropic amines, carboxylic ionophores, calcium channel antagonists, various cell-penetrating peptides of viral, bacterial, plant, animal, human and synthetic origin, other organic molecules and light-induced techniques. Although the efficacy of the targeted toxins was typically augmented in cell culture hundred or thousand fold, in exceptional cases more than million fold, the combination of several substances harbors new problems including additional side effects, loss of target specificity, difficulties to determine the therapeutic window and cell type-dependent variations. This review critically scrutinizes the chances and challenges of endosomal escape enhancers and their potential role in future developments.

Physiological analysis for enhancing radiation use efficiency (RUE) in rice

International Nuclear Information System (INIS)

Punzalan, B.; Calibo, S.; Jagadish, S.V.K.

2012-01-01

Global dimming, or the decrease in global irradiance has been observed in the last 50 years at a rate of 2.7% per decade. Potential consequences of reduced solar radiation include a decline in total biomass production and productivity. Systematic studies involving rice and its ability to utilize available radiation efficiently under tropical conditions are limited. The study was conducted at the International Rice Research Institute (IRRI), Philippines, during the wet season of 2011 to physiologically analyze enhanced radiation use efficiency (RUE) under natural field conditions with limited sunlight. Five varieties were selected from previous seasons' experiments involving 48 different entries. Among the five entries, two with low yield under low solar radiation were selected to serve as checks. Growth analysis for estimating total biomass production and partitioning was done at key growth stages i.e. mid-tillering, panicle initiation, flowering, 15 days after flowering (15 DAF), and physiological maturity, coupled with analysis of non-structural carbohydrates (NSC). Yield and yield components were recorded at maturity. Results show that poor-performing varieties IR40 and IR54 had significantly more panicles than the other three varieties at flowering, indicating a higher sink to source ratio. NSIC RC 222 had the highest RUE of 1.33, while a 22% reduction in RUE was observed among the poor-performing varieties, which also had the lowest leaf area index (LAI) at 15 DAF. Data on thousand-grain weight revealed that IR40 and IR54 had smaller grain size. In conclusion, the authors hypothesize that either insufficient production or inefficient translocation of NSC might be causing the reduced grain size in poor-performing varieties

Efficacy of wheat germ oil in modulating radiation-induced heart damage in rats

International Nuclear Information System (INIS)

Said, U.Z.; Azab, Kh.Sh.

2006-01-01

Wheat Germ oil is a natural unrefined vegetable oil. It is an excellent source of vitamin E, octacosanol, linoleic and linolenic essential fatty acids, which may be beneficial in neutralizing the free oxygen radicals. This study was designed to investigate the cardio-protective efficacy of wheat germ oil, on radiation-induced oxidative damage in rat's heart. Wheat germ oil was supplemented by gavage to rats at a dose of 81 mg/ kg body wt for 10 successive days pre- and 7 successive days post-exposure to 7 Gy (single dose) of whole body gamma irradiation. The dose of wheat germ oil is equivalent to daily human nutritional supplementation quantity. The results revealed that whole body ?-irradiation of rats produced significant alterations in blood cells picture. The erythrocyte, leucocyte, platelet counts and hemoglobin levels decreased after irradiation. Also, radiation-induced biochemical disorders manifested by significant elevation in xanthine oxidase activity (XO) and thiobarbituric acid reactive substances (TBARS) level, with decrease in reduced glutathione (GSH) content in heart tissues, indicating depression in the antioxidant status. Serum lipid profile as total cholesterol, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C) and triglycerides levels (TG) were significantly higher than normal control rats. Radiation exposure produced a significant rise in the activities of serum markers for heart damage as creatine phosphokinase (CPK), aspartate aminotransferase (AST) and lactic dehydrogenase (LDH) indicating acute cardiac toxicity. Moreover, the obtained results revealed abnormal electrophoretic pattern of LDH isoenzymes in the 7th day after exposure to gamma rays. Three bands only appear on the agarose film comparing with 4 bands in normal control rats. The rats that received wheat germ oil supplement showed significantly less severe damage and remarkable improvement in all of the measured parameters when compared to

Gold nanorod-mediated hyperthermia enhances the efficacy of HPMA copolymer-90Y conjugates in treatment of prostate tumors

International Nuclear Information System (INIS)

Buckway, Brandon; Frazier, Nick; Gormley, Adam J.; Ray, Abhijit; Ghandehari, Hamidreza

2014-01-01

Introduction: The treatment of prostate cancer using a radiotherapeutic 90 Y labeled N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer can be enhanced with localized tumor hyperthermia. An 111 In labeled HPMA copolymer system for single photon emission computerized tomography (SPECT) was developed to observe the biodistribution changes associated with hyperthermia. Efficacy studies were conducted in prostate tumor bearing mice using the 90 Y HPMA copolymer with hyperthermia. Methods: HPMA copolymers containing 1, 4, 7, 10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) were synthesized by reversible addition-fragmentation transfer (RAFT) copolymerization and subsequently labeled with either 111 In for imaging or 90 Y for efficacy studies. Radiolabel stability was characterized in vitro with mouse serum. Imaging and efficacy studies were conducted in DU145 prostate tumor bearing mice. Imaging was performed using single photon emission computerized tomography (SPECT). Localized mild tumor hyperthermia was achieved by plasmonic photothermal therapy using gold nanorods. Results: HPMA copolymer-DOTA conjugates demonstrated efficient labeling and stability for both radionuclides. Imaging analysis showed a marked increase of radiolabeled copolymer within the hyperthermia treated prostate tumors, with no significant accumulation in non-targeted tissues. The greatest reduction in tumor growth was observed in the hyperthermia treated tumors with 90 Y HPMA copolymer conjugates. Histological analysis confirmed treatment efficacy and safety. Conclusion: HPMA copolymer-DOTA conjugates radiolabeled with both the imaging and treatment radioisotopes, when combined with hyperthermia can serve as an image guided approach for efficacious treatment of prostate tumors

Radiation, hypoxia and genetic stimulation: implications for future therapies

International Nuclear Information System (INIS)

Adams, Gerald E.; Hasan, Na'il M.; Joiner, Michael C.

1997-01-01

The cellular stress response, whereby very low doses of cytotoxic agents induce resistance to much higher doses, is an evolutionary defence mechanism and is stimulated following challenges by numerous chemical, biological and physical agents including particularly radiation, drugs, heat and hypoxia. There is much homology in the effects of these agents which are manifest through the up-regulation of various genetic pathways. Low-dose radiation stress influences processes involved in cell-cycle control, signal transduction pathways, radiation sensitivity, changes in cell adhesion and cell growth. There is also homology between radiation and other cellular stress agents, particularly hypoxia. Whereas traditionally, hypoxia was regarded mainly as an agent conferring resistance to radiation, there is now much evidence illustrating the cytokine-like properties of hypoxia as well as radiation. Stress phenomena are likely to be important in risks arising from low doses of radiation. Conversely, exploitation of the stress response in settings appropriate to therapy can be particularly beneficial not only in regard to radiation alone but in combinations of radiation and drugs. Similarly, tissue hypoxia can be exploited in novel ways of enhancing therapeutic efficacy. Bioreductive drugs, which are cytotoxically activated in hypoxic regions of tissue, can be rendered even more effective by hypoxia-induced increased expression of enzyme reductases. Nitric oxide pathways are influenced by hypoxia thereby offering possibilities for novel vascular based therapies. Other approaches are discussed

Enhanced plasma wave detection of terahertz radiation using multiple high electron-mobility transistors connected in series

KAUST Repository

Elkhatib, Tamer A.; Kachorovskiǐ, Valentin Yu; Stillman, William J.; Veksler, Dmitry B.; Salama, Khaled N.; Zhang, Xicheng; Shur, Michael S.

2010-01-01

We report on enhanced room-temperature detection of terahertz radiation by several connected field-effect transistors. For this enhanced nonresonant detection, we have designed, fabricated, and tested plasmonic structures consisting of multiple InGaAs/GaAs pseudomorphic high electron-mobility transistors connected in series. Results show a 1.63-THz response that is directly proportional to the number of detecting transistors biased by a direct drain current at the same gate-to-source bias voltages. The responsivity in the saturation regime was found to be 170 V/W with the noise equivalent power in the range of 10-7 W/Hz0.5. The experimental data are in agreement with the detection mechanism based on the rectification of overdamped plasma waves excited by terahertz radiation in the transistor channel. © 2010 IEEE.

Enhanced plasma wave detection of terahertz radiation using multiple high electron-mobility transistors connected in series

KAUST Repository

Elkhatib, Tamer A.

2010-02-01

We report on enhanced room-temperature detection of terahertz radiation by several connected field-effect transistors. For this enhanced nonresonant detection, we have designed, fabricated, and tested plasmonic structures consisting of multiple InGaAs/GaAs pseudomorphic high electron-mobility transistors connected in series. Results show a 1.63-THz response that is directly proportional to the number of detecting transistors biased by a direct drain current at the same gate-to-source bias voltages. The responsivity in the saturation regime was found to be 170 V/W with the noise equivalent power in the range of 10-7 W/Hz0.5. The experimental data are in agreement with the detection mechanism based on the rectification of overdamped plasma waves excited by terahertz radiation in the transistor channel. © 2010 IEEE.

Radiation Protection Research: Radon in the Indoor Environment and enhanced natural radioactivity

International Nuclear Information System (INIS)

Paridaens, J.

2000-01-01

The objectives of R and D on epidemiological studies concerning radon related to health risks at SCK-CEN is to (1) to apply new techniques for retrospective radon measurements in real field conditions and to assess radon decay product exposure by combining these techniques; and (2) to increase capabilities in mapping and surveying sites possibly or likely contaminated with enhanced levels of natural radiation. Progress and main achievements in 1999 are reported on

Enhanced transmission of terahertz radiation through a periodically modulated slab of layered superconductor

International Nuclear Information System (INIS)

Kadygrob, D V; Slipchenko, T M; Yampol'skii, V A; Makarov, N M; Pérez-Rodríguez, F

2013-01-01

We predict the enhanced transparency of a modulated slab of layered superconductor for terahertz radiation due to the diffraction of an incident wave and the resonance excitation of eigenmodes. The electromagnetic field is transferred from the irradiated side of the slab to the other by excited waveguide modes (WGMs) which do not decay in layered superconductors, in contrast to metals, where the enhanced light transmission is caused by the excitation of evanescent surface waves. We show that a series of resonance peaks can be observed in the dependence of transmittance on the incidence angle when the dispersion curve of the diffracted wave crosses successive dispersion curves for the WGMs. (paper)

Radiation Synthesis and Application of Absorbent Hydrogels to Enhance the Quality of Basadiesel

International Nuclear Information System (INIS)

Nguyen Duy Hang; Pham Thi Le Ha; Tran Thi Thuy; Le Hai; Nguyen Tan Man; Le Huu Tu; Nguyen Trong Hoanh Phong; Tran Thi Tam; Tran Thu Hong; Pham Thi Sam; Nguyen Tuong Li Lan

2013-01-01

Studying on the using ability of radiation synthesis hydrogels to enhance the quality of the biodiesel produced from Basa fish oil was implemented. Radiation synthesis of absorbent hydrogels and their application to removal of contaminants from biodiesel produced from fish oil were the major problems. The preparation of the super absorbent hydrogel obtained by radiation induced cross linking of polyacrylamide and polyacrylic was investigated and its application in removal of water, catalyst from the basadiesel emulsion is reported. The hydrogels were characterized in terms of gel content, swelling, character of water and mineral catalyst removal were studied. The effect of temperature, NaOH and KOH content of solution on the swelling degree of hydrogels was also determined. The results showed that the gel fraction of PAAm/PAAc hydrogel with PAAm/AAc (1/4) ratio and dose of 20 kGy was used to synthesized the Gel of A-311. Studies also made on the application of Gel A-311 during the refining process in Basadiesel industry. (author)

Perceived collective teacher efficacy in low performing schools

African Journals Online (AJOL)

Education Management and Leadership, School for Professional Studies in ... enhance collective teacher efficacy, the challenge of low-performing schools ... Collective teacher efficacy, therefore, involves the combined perceptions of ... because greater efficacy leads to greater effort and ... One of the strategies for sharing.

Efficacy of Clove Oil in Modulating Radiation-Induced Some Biochemical Disorders in Male Rats

International Nuclear Information System (INIS)

Nada, A.S.

2011-01-01

The current study was conducted to evaluate the possible modulating efficacy of prolonged oral administration of clove oil against gamma irradiation-induced some biochemical disorders in male rats. Clove oil was orally administrated in a concentration of 200 mg/kg body wt daily for 21 days before irradiation at a single dose of 7 Gy and for 7 days post exposure. Transaminases (AST and ALT), alkaline phosphatase (ALP), lipid profile; cholesterol, triglycerides (T.G) and low density lipoprotein (LDL) as well as serum glucose level were determined. Also, liver reduced glutathione (GSH) content and lipid peroxidation were estimated in addition to the hepatic concentration levels of some trace elements (Fe, Cu, Zn, and Se). Rats exposed to ionizing radiation revealed transaminases disorders, lipid abnormalities, elevation in serum glucose, ALP activity as well as liver TBARS. A sharp drop in glutathione was recorded. Also, radiation induced alteration in hepatic trace element contents. The obtained data show that rats treated with clove oil before and after whole body gamma irradiation exhibited significant amelioration in liver marker enzymes, serum glucose and lipids as well as noticeable improvement in liver glutathione contents. Clove oil was also effective in minimizing lipid pr oxidation and trace element alteration induced by irradiation. It could be concluded that clove oil exerts a beneficial protective role against gamma irradiation

Study on Efficacy of Gamma Radiation on the Inactivation of Highly Pathogenic Avian Influenza Virus H5N1 (Thai isolate) in Chicken Meat and Chicken Feces

International Nuclear Information System (INIS)

Pinyochon, Wasana; Piadang, Nattayana; Mulika, Ladda; Parchariyanon, Sujira; Vitittheeranon, Arag; Damrongwatapokin, Sudarat

2006-09-01

A study on the efficacy of gamma radiation on the inactivation of a highly pathogenic avian influenza virus H5N1 subtype, Thai isolate was carried out. The virus was in the form frozen infected allantoic fluid frozen chicken meat and frozen chicken feces. The result indicated that 9 kilo grey of gamma radiation could completely inactivated 106.0 EID50/ml of AIV infected allantoic fluid and 22 kiel grey and 15 kilo grey of gamma radiation completely inactivate 106.0 EID50/10/ grams of chicken meat and 106.0 EID50/5 grams of chicken feces respectively.

Strontium-doped calcium polyphosphate/ultrahigh molecular weight polyethylene composites: A new class of artificial joint components with enhanced biological efficacy to aseptic loosening

International Nuclear Information System (INIS)

Gu, Zhipeng; Huang, Bingxue; Li, Yiwen; Tian, Meng; Li, Li; Yu, Xixun

2016-01-01

To enhance implant stability and prolong the service life of artificial joint component, a new approach was proposed to improve the wear resistance of artificial joint component and endow artificial joint component with the biological efficacy of resistance to aseptic loosening. Strontium calcium polyphosphate (SCPP) were interfused in ultrahigh molecular weight polyethylene (UHMWPE) by a combination of liquid nitrogen ball-milling and flat-panel curing process to prepare the SCPP/UHMWPE composites. The micro-structure, mechanical characterization, tribological characterization and bioactivities of various SCPP/UHMWPE composites were investigated. The results suggested that this method could statistically improve the wear resistance of UHMWPE resulting from a good SCPP particle dispersion. Moreover, it is also observed that the SCPP/UHMWPE composites-wear particles could promote the production of OPG by osteoblasts and decrease the production of RANKL by osteoblasts, and then increase the OPG/RANKL ratio. This indicated that the SCPP/UHMWPE composites had potential efficacy to prevent and treat aseptic loosening. Above all, the SCPP/UHMWPE composites with a suitable SCPP content would be the promising materials for fabricating artificial joint component with ability to resist aseptic loosening. - Highlights: • SCPP/UHMWPE composites could enhance biological efficacy of resistance to aseptic loosening. • SCPP would improve biological efficacy with a few sacrifice of wear resistance. • The results might provide a promising wear-resistant material for fabricating acetabular cup.

Strontium-doped calcium polyphosphate/ultrahigh molecular weight polyethylene composites: A new class of artificial joint components with enhanced biological efficacy to aseptic loosening

Energy Technology Data Exchange (ETDEWEB)

Gu, Zhipeng [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu 610041 (China); Huang, Bingxue; Li, Yiwen [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Tian, Meng [Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu 610041 (China); Li, Li [Department of Oncology, the 452 Hospital of Chinese PLA, Chengdu 610021 (China); Yu, Xixun, E-mail: yuxixun@163.com [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China)

2016-04-01

To enhance implant stability and prolong the service life of artificial joint component, a new approach was proposed to improve the wear resistance of artificial joint component and endow artificial joint component with the biological efficacy of resistance to aseptic loosening. Strontium calcium polyphosphate (SCPP) were interfused in ultrahigh molecular weight polyethylene (UHMWPE) by a combination of liquid nitrogen ball-milling and flat-panel curing process to prepare the SCPP/UHMWPE composites. The micro-structure, mechanical characterization, tribological characterization and bioactivities of various SCPP/UHMWPE composites were investigated. The results suggested that this method could statistically improve the wear resistance of UHMWPE resulting from a good SCPP particle dispersion. Moreover, it is also observed that the SCPP/UHMWPE composites-wear particles could promote the production of OPG by osteoblasts and decrease the production of RANKL by osteoblasts, and then increase the OPG/RANKL ratio. This indicated that the SCPP/UHMWPE composites had potential efficacy to prevent and treat aseptic loosening. Above all, the SCPP/UHMWPE composites with a suitable SCPP content would be the promising materials for fabricating artificial joint component with ability to resist aseptic loosening. - Highlights: • SCPP/UHMWPE composites could enhance biological efficacy of resistance to aseptic loosening. • SCPP would improve biological efficacy with a few sacrifice of wear resistance. • The results might provide a promising wear-resistant material for fabricating acetabular cup.

T-regulatory cells depletion is the main cause for enhanced antitumor immunity during radio-sensitization of tumors by 2-deoxy-D-glucose

International Nuclear Information System (INIS)

Farooque, Abdullah; Verma, Amit; Singh, Niharika; Chauhan, Sachin Kumar Singh; Jethani, Jyoti; Adhikari, J.S.; Dwarakanath, B.S.; Afrin, Farhat

2014-01-01

Regulatory T cells (Tregs) are known to have profound effects in blocking anti-tumor immunity. Therefore, Tregs are seen as a major hurdle that must be overcome in order to improve the efficacy of cancer therapy. The glycolytic inhibitor, 2-deoxy-d-glucose (2-DG) enhances radiation and chemotherapeutics induced death of many cancer cells in vitro and local tumor control in vivo, which was found to be associated with the enhanced anti-tumor immunity. Therefore, we investigated the role of Tregs in determining the tumor response to the combined treatment of 2-DG plus ionizing radiation. Ehrlich ascites tumor bearing mice were administered with a single dose of 2-DG (2 gm/Kg/b.wt) intravenously just before focal irradiation (10 Gy). Immuno-phenotyping of Tregs in secondary lymphoid organs was carried out using flow cytometry, while related cytokines were analyzed using bead array and ELISA. Further, mRNA and protein levels of transcription factors were assessed in sorted splenic CD4 + cells and CD4 + CD25 + using real time PCR and Western blot techniques. Results clearly showed depletion (TRAIL mediated apoptosis) of T regs (CD4 + CD25 + FoxP3 + CD39 + FR4 + GITR + CD127 - ), in blood, spleen, lymph node and tumor following the combined treatment. This led to the immune activation in the periphery, secondary lymphoid organs and massive infiltration of CD4 + , CD8 + and NK cells in the tumor, which correlated well with the complete response (cure; tumor free survival). Association of Treg depletion with the tumor response was further confirmed using low doses of cyclophosphamide (which depletes Tegs) and rapamycin (activator of Tregs),wherein the depletor of Tregs enhanced the efficacy of combined treatment, while Tregs enhancer compromised the efficacy. These studies unequivocally established the role of Tregs in determining the therapeutic response and can be used as a target for enhancing the efficacy of this combined treatment, besides establishing the potential of

Antioxidant efficacy of crude methanol extract of ashitaba green tea against radiation induced oxidative stress in E.coli K12 bacteria

International Nuclear Information System (INIS)

Darshan Raj, C.G.; Sindhu Priya, E.S.; Sarojini, B.K.

2013-01-01

This study was undertaken to evaluate the antioxidant activity of methanol crude extract of ashitaba green tea (G). The DPPH scavenging assay was evaluated for green tea extract to determine its radical scavenging capacity. The bacteria was pretreated with ashitaba green tea extract, quercetin (Q) and (-) epigallocatechin -3-gallate (E) at below MIC level. Oxidative stress was induced at 0.4 Gy using gamma radiation. The antioxidant efficacy of ashitaba green tea was evaluated through enzyme antioxidant studies like SOD (Superoxidedismutase) and CAT (Catalase). The oxidative stress marker Thiobarbituric acid-reactive substance (TBARS) was also evaluated. Further the protective efficacy of the(G) was confirmed by colony forming units (CFU) study. Among the tested compounds the crude extract of ashitaba (G) exhibited excellent antioxidant activity in comparison with quercetin and (-) epigallocatechin -3-gallate. (abstract)

Protection Motivation and Self-Efficacy: A Model of Health Enhancement.

Science.gov (United States)

Stanley, Melinda A.

Protection motivation theory proposes that a perceived threat to health activates cognitive appraisals of the severity of the threatened event, the probability of its occurrence, and the efficacy of a coping response; a recent reformulation of the theory incorporates self-efficacy expectancy as a fourth mediating cognitive process. To test the…

Protective efficacy of Emblica against radiation and lead induced changes in the Jejunum of Swiss Albino mice

International Nuclear Information System (INIS)

Purohit, R.K.; Meena, Dinesh; Issran, Rakesh; Pyarelal; Jangir, Ashok Kumar

2014-01-01

Recently, increased interest has developed on search for potential drugs of plant origin which can quench the radiation induced free radicals and eliminate oxygen with minimum side effects. In view of the fact, present study was planned to evaluate the protective efficacy of Emblica against radiation and lead induced changes in jejunum of mice. For the purpose, six to eight weeks old male Swiss albino mice were selected and divided into seven groups on the basis of radiation, lead, combined treatment and drug treated. The values of total proteins, cholesterol, acid phosphatase activity, alkaline phosphatase activity, DNA and RNA were estimated. The values of total proteins, cholesterol, DNA and RNA decreased whereas acid phosphatase and alkaline phosphatase activity increased. After irradiation with various doses of gamma rays, histological changes depend upon the dose of radiation delivered. The important radio-lesions were looseness of musculatrue, hydropic degeneration in submucosa and lamina propria, hyperaemia and haemorrhage in submucosa, pyknotic cells, cytoplasmic degranulation and vacuolation, abnormal mitotic figures. Karyolysis, karyorrhexis and chromatolysis were also observed in crypt cells. Shortening and breaking of villus tips, leucocytic infiltration in lamina propria and cell debris in intestinal lumen were also noted. The number of goblet cells per crypt section also decreased in all the experimental groups. The value of the experimental groups was significantly lower than that of the control group. The biochemical finding indicated the drug treated section of living tissue showed slightly/no degenerative changes. The drug treated groups demonstrating the ability of Aloe vera to inhibit oxidative stress thus preventing tissue injury. (author)

Alteration of foliar flavonoid chemistry induced by enhanced UV-B radiation in field-grown Pinus ponderosa, Quercus rubra and Pseudotsuga menziesii.

Science.gov (United States)

Warren, Jeffrey M; Bassman, John H; Mattinson, D Scott; Fellman, John K; Edwards, Gerald E; Robberecht, Ronald

2002-03-01

Chromatographic analyses of foliage from several tree species illustrate the species-specific effects of UV-B radiation on both quantity and composition of foliar flavonoids. Pinus ponderosa, Quercus rubra and Pseudotsuga menziesii were field-grown under modulated ambient (1x) and enhanced (2x) biologically effective UV-B radiation. Foliage was harvested seasonally over a 3-year period, extracted, purified and the flavonoid fraction applied to a mu Bondapak/C(18) column HPLC system sampling at 254 nm. Total flavonoid concentrations in Quercus rubra foliage were more than twice (leaf area basis) that of the other species; Pseudotsuga menziesii foliage had intermediate levels and P. ponderosa had the lowest concentrations of total flavonoids. No statistically significant UV-B radiation-induced effects were found in total foliar flavonoid concentrations for any species; however, concentrations of specific compounds within each species exhibited significant treatment effects. Higher (but statistically insignificant) levels of flavonoids were induced by UV-B irradiation in 1- and 2-year-old P. ponderosa foliage. Total flavonoid concentrations in 2-year-old needles increased by 50% (1x ambient UV-B radiation) or 70% (2x ambient UV-B radiation) from that of 1-year-old tissue. Foliar flavonoids of Q. rubra under enhanced UV-B radiation tended to shift from early-eluting compounds to less polar flavonoids eluting later. There were no clear patterns of UV-B radiation effects on 1-year-old P. menziesii foliage. However, 2-year-old tissue had slightly higher foliar flavonoids under the 2x UV-B radiation treatment compared to ambient levels. Results suggest that enhanced UV-B radiation will alter foliar flavonoid composition and concentrations in forest tree species, which could impact tissue protection, and ultimately, competition, herbivory or litter decomposition.

SU-E-T-279: Dose Enhancement Effect Due to Cerium Oxide Nanoparticles Employed as Radiation Protectants

Energy Technology Data Exchange (ETDEWEB)

Ouyang, Z; Altundal, Y; Sajo, E [Univ Massachusetts Lowell, Lowell, MA (United States); Ngwa, W [Univ Massachusetts Lowell, Lowell, MA (United States); Brigham and Women’s Hospital, Dana Farber Cancer Institute, Harvard Medical, Boston, MA (United States)

2015-06-15

Purpose: The goal of radiotherapy is to maximize radiation dose to diseased cells while minimizing radiation damage to normal tissues. In order to minimize damage to normal tissues, cerium oxide nanoparticles (nanoceria) are currently considered as a radioprotectant. However, some studies have reported concerns that nanoceria can also lead to radiotherapy dose enhancement due to the high atomic number of cerium, especially when used in conjunction with kV energy and brachytherapy sources. In this study, this concern is investigated to determine if the concentrations of nanoceria employed in in-vivo studies to confer radioprotection can engender a significant dose enhancement. Methods: Radiation with energies ranging from 50kVp to 140kVp is investigated in this work along with brachytherapy sources Pd-103 and I-125. A previously established theoretical model is used to calculate the dose enhancement factor (DEF). In this model, each cell is assumed to be a voxel of size (10 µm, 10 µm, 10 µm) with nanoceria homogeneously distributed among them. Electron energy loss formula of Cole is used to calculate energy (and hence dose) deposited by photoelectrons and Auger electrons in each tissue voxel due to irradiation of nanoceria. The DEF is defined as the ratio of the dose with and without nanoparticles. Results: DEF calculation results are smaller than 1.02 with dosages of nanoceria smaller than 0.645 mg/g, which is shown to be sufficiently protective by some previous in-vitro and in-vivo experiments. The brachytherapy sources show higher DEF’s than kVp radiations. DEF peaks are consistent with K shell and L shell energies of cerium, 40 keV and 6 keV, respectively. Conclusion: The results show that for sufficiently radioprotective concentrations of nanoceria, there will be minimal DEF when used in conjunction with clinically applicable kV energy radiotherapy sources or brachytherapy sources.

Cystic echinococcosis therapy: Albendazole-loaded lipid nanocapsules enhance the oral bioavailability and efficacy in experimentally infected mice.

Science.gov (United States)

Pensel, Patricia E; Ullio Gamboa, Gabriela; Fabbri, Julia; Ceballos, Laura; Sanchez Bruni, Sergio; Alvarez, Luis I; Allemandi, Daniel; Benoit, Jean Pierre; Palma, Santiago D; Elissondo, María C

2015-12-01

Therapeutic failures attributed to medical management of cystic echinococcosis (CE) with albendazole (ABZ) have been primarily linked to the poor drug absorption rate resulting in low drug level in plasma and hydatid cysts. Lipid nanocapsules (LNCs) represent nanocarriers designed to encapsulate lipophilic drugs, such as ABZ. The goals of the current work were: (i) to characterize the plasma and cyst drug exposure after the administration of ABZ as ABZ-LNCs or ABZ suspension (ABZ-SUSP) in mice infected with Echinococcus granulosus, and ii) to compare the clinical efficacies of both ABZ formulations. Enhanced ABZ sulphoxide (ABZ-SO) concentration profiles were obtained in plasma and cysts from ABZ-LNC treated animals. ABZSO exposure (AUC0-LOQ) was significantly higher in plasma and cyst after the ABZ-LNC treatments, both orally and subcutaneously, compared to that observed after oral administration of ABZ-SUSP. Additionally, ABZSO concentrations measured in cysts from ABZ-LNC treated mice were 1.7-fold higher than those detected in plasma. This enhanced drug availability correlated with an increased efficacy against secondary CE in mice observed for the ABZ-LNCs, while ABZ-SUSP did not reach differences with the untreated control group. This new pharmacotechnically-based strategy could be a potential alternative to improve the treatment of human CE. Copyright © 2015 Elsevier B.V. All rights reserved.

Radiative heat transfer enhancement using geometric and spectral control for achieving high-efficiency solar-thermophotovoltaic systems

Science.gov (United States)

Kohiyama, Asaka; Shimizu, Makoto; Yugami, Hiroo

2018-04-01

We numerically investigate radiative heat transfer enhancement using spectral and geometric control of the absorber/emitter. A high extraction of the radiative heat transfer from the emitter as well as minimization of the optical losses from the absorber leads to high extraction and solar thermophotovoltaic (STPV) system efficiency. The important points for high-efficiency STPV design are discussed for the low and high area ratio of the absorber/emitter. The obtained general guideline will support the design of various types of STPV systems.

Enhancement of terahertz radiation in a Smith-Purcell backward-wave oscillator by an inverse wet-etched grating

International Nuclear Information System (INIS)

Kim, Jung-Il; Jeon, Seok-Gy; Kim, Geun-Ju; Kim, Jaehong

2011-01-01

A terahertz (THz) Smith-Purcell (SP) backward-wave oscillator with an inverse wet-etched grating based on silicon has been proposed to enhance radiation intensity. This grating strengthens the interactions between an electron beam and the evanescent wave due to the adjacent surface structure between gratings that improves the magnitude of the electric field up to 1.7 times compared to the conventional rectangular gratings. A two-dimensional particle-in-cell (PIC) simulation shows that the radiated power is increased up to 2.3 times higher at the radiated frequency of 0.66 THz for an electron-beam energy of 30 keV.

Spatial characterization of relativistic electron enhancements in the Earth's outer radiation belt during the Van Allen Probes era

Science.gov (United States)

Pinto, V. A.; Bortnik, J.; Moya, P. S.; Lyons, L. R.; Sibeck, D. G.; Kanekal, S. G.

2017-12-01

Using Van Allen Probes Relativistic Electron-Proton Telescope (REPT) instrument we have identified 73 relativistic electron enhancement events in the outer radiation belt that occurred at different L values between L = 2.5 and L = 6.0. To determine an enhancement, we have used three different identification methods. We then determine the radial location, MLT location, timing and strength of those enhancements. We discuss the differences of each of the methods and test them to pinpoint the origin and spatial propagation of each enhancement. We have classified the events based on the radial propagation, speed of enhancement and intensity of fluxes and response for energy channels ranging from 1.8 MeV to 6.3 MeV. In addition, we have used OMNI data to study the statistical properties of the solar wind during each event and have classified similarities and differences that might be relevant for each group of enhancements and help us determine the physical process responsible for different types of enhancements. Additionally, we have used >2 MeV electron fluxes at geostationary orbit as measured by the GOES 13 and 15 Energetic Particle Sensor (EPS) instrument to compare our results with the geostationary orbit. Our results suggest that under certain conditions GOES data can be used to predict fluxes at the core of the radiation belt and vice-versa.

Radiative absorption enhancement of dust mixed with anthropogenic pollution over East Asia

Directory of Open Access Journals (Sweden)

P. Tian

2018-06-01

Full Text Available The particle mixing state plays a significant yet poorly quantified role in aerosol radiative forcing, especially for the mixing of dust (mineral absorbing and anthropogenic pollution (black carbon absorbing over East Asia. We have investigated the absorption enhancement of mixed-type aerosols over East Asia by using the Aerosol Robotic Network observations and radiative transfer model calculations. The mixed-type aerosols exhibit significantly enhanced absorbing ability than the corresponding unmixed dust and anthropogenic aerosols, as revealed in the spectral behavior of absorbing aerosol optical depth, single scattering albedo, and imaginary refractive index. The aerosol radiative efficiencies for the dust, mixed-type, and anthropogenic aerosols are −101.0, −112.9, and −98.3 Wm−2 τ−1 at the bottom of the atmosphere (BOA; −42.3, −22.5, and −39.8 Wm−2 τ−1 at the top of the atmosphere (TOA; and 58.7, 90.3, and 58.5 Wm−2 τ−1 in the atmosphere (ATM, respectively. The BOA cooling and ATM heating efficiencies of the mixed-type aerosols are significantly higher than those of the unmixed aerosol types over the East Asia region, resulting in atmospheric stabilization. In addition, the mixed-type aerosols correspond to a lower TOA cooling efficiency, indicating that the cooling effect by the corresponding individual aerosol components is partially counteracted. We conclude that the interaction between dust and anthropogenic pollution not only represents a viable aerosol formation pathway but also results in unfavorable dispersion conditions, both exacerbating the regional air pollution in East Asia. Our results highlight the necessity to accurately account for the mixing state of aerosols in atmospheric models over East Asia in order to better understand the formation mechanism for regional air pollution and to assess its impacts on human health, weather, and climate.

Microbubble-based enhancement of radiation effect: Role of cell membrane ceramide metabolism.

Directory of Open Access Journals (Sweden)

Azza Al-Mahrouki

Full Text Available Ultrasound (US stimulated microbubbles (MB is a new treatment approach that sensitizes cancer cells to radiation (XRT. The molecular pathways in this response remain unelucidated, however, previous data has supported a role for cell membrane-metabolism related pathways including an up regulation of UDP glycosyltransferase 8 (UGT8, which catalyzes the transfer of galactose to ceramide, a lipid that is associated with the induction of apoptotic signalling. In this study, the role of UGT8 in responses of prostate tumours to ultrasound-stimulated microbubble radiation enhancement therapy is investigated. Experiments were carried out with cells in vitro and tumours in vivo in which UGT8 levels had been up regulated or down regulated. Genetically modified PC3 cells were treated with XRT, US+MB, or a combination of XRT+US+MB. An increase in the immunolabelling of ceramide was observed in cells where UGT8 was down-regulated as opposed to cells where UGT8 was either not regulated or was up-regulated. Clonogenic assays have revealed a decreased level of cellular survival with the down-regulation of UGT8. Xenograft tumours generated from stably transfected PC3 cells were also treated with US+MB, XRT or US+MB+XRT. Histology demonstrated more cellular damage in tumours with down-regulated UGT8 in comparison with control tumours. In contrast, tumours with up-regulated UGT8 had less damage than control tumours. Power Doppler imaging indicated a reduction in the vascular index with UGT8 down-regulation and photoacoustic imaging revealed a reduction in oxygen saturation. This was contrary to when UGT8 was up regulated. The down regulation of UGT8 led to the accumulation of ceramide resulting in more cell death signalling and therefore, a greater enhancement of radiation effect when vascular disruption takes place through the use of ultrasound-stimulated microbubbles.

Radiation-enhanced short channel effects due to multi-dimensional influence from charge at trench isolation oxides

International Nuclear Information System (INIS)

Youk, G.U.; Khare, P.S.; Schrimpf, R.D.; Massengill, L.W.; Galloway, K.F.

1999-01-01

Radiation enhanced drain induced barrier lowering (DIBL) was experimentally observed and verified by 3-D simulations for submicron devices with trench isolation oxides. Submicron MOSFETs with shallow trench isolation were exposed to total-ionizing-dose radiation. Prior to irradiation, the devices exhibited near-ideal current-voltage characteristics, with no significant short-channel effects for as-drawn gate lengths of 0.4 microm. Following irradiation, the off-state leakage current increased significantly for total doses above about 650 krad(SiO 2 ). In addition, the irradiated devices exhibited DIBL that increased the drain current by 5--10x for a gate length of 0.4 microm (the nominal minimum gate length for this process) and much more for slightly shorter devices (0.35 microm). The increase in the off-state leakage current and the accompanying DIBL are shown to be associated with a parasitic field-effect transistor that is present at the edge of the shallow trench. Three-dimensional simulations are used to illustrate the effect. Simulations show that trapped charge at the trench sidewalls enhance the DIBL by depleting the edges of the channel. Radiation-induced charge may decrease the effectiveness of short-channel engineering

Rituximab enhances radiation-triggered apoptosis in non-Hodgkin's lymphoma cells via caspase-dependent and - independent mechanisms

International Nuclear Information System (INIS)

Skvortsova, I.; Skvortsov, S.; Popper, B.A.; Haidenberger, A.; Saurer, M.; Gunkel, A.R.; Zwierzina, H.; Lukas, P.

2006-01-01

Rituximab (RTX), a chimeric human anti-CD20 monoclonal antibody, is currently employed in the treatment of malignant non-Hodgkin's lymphoma (NHL) either alone or in combination with other cytotoxic approaches. The present study examines the effects of ionizing radiation in combination with RTX on proliferation and apoptosis development in B-lymphoma RL and Raji cells. RTX was used at a concentration of 10 μg/mL 24 hours prior to irradiation at a single dose of 9 Gy. CD20 expression, cell viability, apoptosis, mitochondrial membrane potential and apoptosis-related proteins were evaluated in the treated B cells. The constitutive level of CD20 expression in RL and Raji lymphoma cells did not play an essential role in RTX-induced cell growth delay. Both lymphoma cells showed similar inhibition of cell proliferation without apoptosis development in response to RTX treatment. Exposure to ionizing radiation induced cell growth delay and apoptosis in RL cells, whereas Raji cells showed moderate radio-resistance and activation of cell growth at 24 hours after irradiation, which was accompanied by increased radiation-triggered CD20 expression. The simultaneous exposure of lymphoma cells to ionizing radiation and RTX abrogated radioresistance of Raji cells and significantly enhanced cell growth delay and apoptosis in RL cells. X-linked inhibitor of apoptosis protein (XIAP) and the inducible form of heat shock protein 70 (Hsp70) were positively modulated by RTX in combination with ionizing radiation in order to induce apoptosis. Furthermore, it was demonstrated that mitochondrial membrane potential dissipation is not an essential component to induce apoptosis-inducing factor (AIF) maturation and apoptosis. Our results show that RTX-triggered enhancement of radiation-induced apoptosis and cell growth delay is achieved by modulation of proteins involved in programmed cell death. (author)

Heat transfer enhancement

International Nuclear Information System (INIS)

Hasatani, Masanobu; Itaya, Yoshinori

1985-01-01

In order to develop energy-saving techniques and new energy techniques, and also most advanced techniques by making industrial equipment with high performance, heat transfer performance frequently becomes an important problem. In addition, the improvement of conventional heat transfer techniques and the device of new heat transfer techniques are often required. It is most proper that chemical engineers engage in the research and development for enhancing heat transfer. The research and development for enhancing heat transfer are important to heighten heat exchange efficiency or to cool equipment for preventing overheat in high temperature heat transfer system. In this paper, the techniques of enhancing radiative heat transfer and the improvement of radiative heat transfer characteristics are reported. Radiative heat transfer is proportional to fourth power of absolute temperature, and it does not require any heat transfer medium, but efficient heat-radiation converters are necessary. As the techniques of enhancing radiative heat transfer, the increase of emission and absorption areas, the installation of emissive structures and the improvement of radiative characteristics are discussed. (Kako, I.)

Cyclosporine promotes the induction of thymic lymphomas in C57BL/6 mice initiated by a single dose of γ-radiation

International Nuclear Information System (INIS)

Yabu, Koji; Warty, V.S.; Gorelik, E.; Shinozuka, Hisashi

1991-01-01

We previously demonstrated that a single dose of γ-radiation (350 rads) was able to induce thymic lymphomas in C57BL mice when followed by promoting treatment with oral cyclosporine (CsA), a non-genotoxic immunosuppressant. We have now tested the efficacy of various doses of γ-radiation as an initiator of CsA promotion of the induction of thymic lymphomas in male C57BL mice. The effects of oral CsA on the splenic natural killer (NK) cell activity of non-irradiated and irradiated (400 rads, 1X) mice were tested by the standard 51 Cr release assays against YAC-1 cells. The cumulative incidence of thymic lymphomas induced by a single dose of γ-radiation at 100, 200, 400 and 600 rads were 10, 25, 63 and 75% respectively, after 42 weeks of CsA promotion. The splenic NK cell activity in non-irradiated mice given CsA for 4 weeks was twice as high as that in the control mice. CsA inhibited poly I:C-induced augmentation of the splenic NK cell activity. In mice given a single dose (400 rads) of γ-radiation and CsA for 4 weeks, a similar but reduced enhancement of the splenic NK cell activity as seen in non-irradiated mice was observed. These results indicate that the efficacy of CsA promotion in the induction of thymic lymphomas is dependent on the initiating doses of γ-radiation, and that CsA enhances host splenic NK cell activity during the early stage of tumor promotion. (author)

AKT-mediated enhanced aerobic glycolysis causes acquired radioresistance by human tumor cells

International Nuclear Information System (INIS)

Shimura, Tsutomu; Noma, Naoto; Sano, Yui; Ochiai, Yasushi; Oikawa, Toshiyuki; Fukumoto, Manabu; Kunugita, Naoki

2014-01-01

Background and purpose: Cellular radioresistance is a major impediment to effective radiotherapy. Here, we demonstrated that long-term exposure to fractionated radiation conferred acquired radioresistance to tumor cells due to AKT-mediated enhanced aerobic glycolysis. Material and methods: Two human tumor cell lines with acquired radioresistance were established by long-term exposure to fractionated radiation with 0.5 Gy of X-rays. Glucose uptake was inhibited using 2-deoxy-D-glucose, a non-metabolizable glucose analog. Aerobic glycolysis was assessed by measuring lactate concentrations. Cells were then used for assays of ROS generation, survival, and cell death as assessed by annexin V staining. Results: Enhanced aerobic glycolysis was shown by increased glucose transporter Glut1 expression and a high lactate production rate in acquired radioresistant cells compared with parental cells. Inhibiting the AKT pathway using the AKT inhibitor API-2 abrogated these phenomena. Moreover, we found that inhibiting glycolysis with 2-deoxy-D-glucose suppressed acquired tumor cell radioresistance. Conclusions: Long-term fractionated radiation confers acquired radioresistance to tumor cells by AKT-mediated alterations in their glucose metabolic pathway. Thus, tumor cell metabolic pathway is an attractive target to eliminate radioresistant cells and improve radiotherapy efficacy

Experimental and numerical study on heat transfer enhancement of flat tube radiator using Al2O3 and CuO nanofluids

Science.gov (United States)

Alosious, Sobin; R, Sarath S.; Nair, Anjan R.; Krishnakumar, K.

2017-12-01

Forced convective heat transfer of Al2O3 and CuO nanofluids through flat tube automobile radiator were studied experimentally and numerically. Nanofluids of 0.05% volume concentrations were prepared with Al2O3 and CuO nanoparticles having diameter below 50 nm. The working fluid recirculates through an automobile flat tube radiator with constant inlet temperature of 90 °C. Experiments were conducted by using water and nanofluids by varying the Reynolds numbers from 136 to 816. The flat tube of the radiator with same dimensions were modeled and numerically studied the heat transfer. The model includes the thickness of tube wall and also considers the effect of fins in the radiator. Numerical studies were carried out for six different volume concentrations from 0.05% to 1% and Reynolds number varied between 136 and 816 for both nanofluids. The results show an enhancement in heat transfer coefficient and effectiveness of radiator with increase in Reynolds number and volume concentration. A maximum enhancement of 13.2% and 16.4% in inside heat transfer coefficient were obtained for 1% concentration of CuO and Al2O3 nanofluids respectively. However increasing the volume concentration causes an increase in viscosity and density, which leads to an increase in pumping power. For same heat rejection of water, the area of the radiator can be reduced by 2.1% and 2.9% by using 1% concentration of CuO and Al2O3 nanofluids respectively. The optimum values of volume concentration were found to be 0.4% to 0.8% in which heat transfer enhancement dominates pumping power increase. Al2O3 nanofluids gives the maximum heat transfer enhancement and stability compared to CuO nanofluids.

Safety and Efficacy of Stereotactic Ablative Radiation Therapy for Renal Cell Carcinoma Extracranial Metastases

International Nuclear Information System (INIS)

Wang, Chiachien Jake; Christie, Alana; Lin, Mu-Han; Jung, Matthew; Weix, Derek; Huelsmann, Lorel; Kuhn, Kristin; Meyer, Jeffrey; Desai, Neil; Kim, D. W. Nathan; Pedrosa, Ivan; Margulis, Vitaly; Cadeddu, Jeffrey; Sagalowsky, Arthur; Gahan, Jeffrey; Laine, Aaron; Xie, Xian-Jin; Choy, Hak; Brugarolas, James; Timmerman, Robert

2017-01-01

Purpose: Renal cell carcinoma is refractory to conventional radiation therapy but responds to higher doses per fraction. However, the dosimetric data and clinical factors affecting local control (LC) are largely unknown. We aimed to evaluate the safety and efficacy of stereotactic ablative radiation therapy (SAbR) for extracranial renal cell carcinoma metastases. Methods and Materials: We reviewed 175 metastatic lesions from 84 patients treated with SAbR between 2005 and 2015. LC and toxicity after SAbR were assessed with Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 and Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Predictors of local failure were analyzed with χ 2 , Kaplan-Meier, and log-rank tests. Results: In most cases (74%), SAbR was delivered with total doses of 40 to 60 Gy, 30 to 54 Gy, and 20 to 40 Gy in 5 fractions, 3 fractions, and a single fraction, respectively. The median biologically effective dose (BED) using the universal survival model was 134.5 Gy. The 1-year LC rate after SAbR was 91.2% (95% confidence interval, 84.9%-95.0%; median follow-up, 16.7 months). Local failures were associated with prior radiation therapy (hazard ratio [HR], 10.49; P<.0001), palliative-intent radiation therapy (HR, 4.63; P=.0189), spinal location (HR, 5.36; P=.0041), previous systemic therapy status (0-1 vs >1; HR, 3.52; P=.0217), and BED <115 Gy (HR, 3.45; P=.0254). Dose received by 99% of the target volume was the strongest dosimetric predictor for LC. Upon multivariate analysis, dose received by 99% of the target volume greater than BED of 98.7 Gy and systemic therapy status remained significant (HR, 0.12 and 3.64, with P=.0014 and P=.0472, respectively). Acute and late grade 3 toxicities attributed to SAbR were observed in 3 patients (1.7%) and 5 patients (2.9%), respectively. Conclusions: SAbR demonstrated excellent LC of metastatic renal cell carcinoma with a favorable safety profile when an adequate dose and

Safety and Efficacy of Stereotactic Ablative Radiation Therapy for Renal Cell Carcinoma Extracranial Metastases

Energy Technology Data Exchange (ETDEWEB)

Wang, Chiachien Jake [Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Christie, Alana [Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Lin, Mu-Han; Jung, Matthew; Weix, Derek; Huelsmann, Lorel; Kuhn, Kristin; Meyer, Jeffrey; Desai, Neil; Kim, D. W. Nathan [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Pedrosa, Ivan [Department of Radiology, Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Margulis, Vitaly; Cadeddu, Jeffrey; Sagalowsky, Arthur; Gahan, Jeffrey [Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Laine, Aaron [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Xie, Xian-Jin [Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Choy, Hak [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Brugarolas, James [Kidney Cancer Program, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Division of Hematology/Oncology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Timmerman, Robert [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); and others

2017-05-01

Purpose: Renal cell carcinoma is refractory to conventional radiation therapy but responds to higher doses per fraction. However, the dosimetric data and clinical factors affecting local control (LC) are largely unknown. We aimed to evaluate the safety and efficacy of stereotactic ablative radiation therapy (SAbR) for extracranial renal cell carcinoma metastases. Methods and Materials: We reviewed 175 metastatic lesions from 84 patients treated with SAbR between 2005 and 2015. LC and toxicity after SAbR were assessed with Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 and Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Predictors of local failure were analyzed with χ{sup 2}, Kaplan-Meier, and log-rank tests. Results: In most cases (74%), SAbR was delivered with total doses of 40 to 60 Gy, 30 to 54 Gy, and 20 to 40 Gy in 5 fractions, 3 fractions, and a single fraction, respectively. The median biologically effective dose (BED) using the universal survival model was 134.5 Gy. The 1-year LC rate after SAbR was 91.2% (95% confidence interval, 84.9%-95.0%; median follow-up, 16.7 months). Local failures were associated with prior radiation therapy (hazard ratio [HR], 10.49; P<.0001), palliative-intent radiation therapy (HR, 4.63; P=.0189), spinal location (HR, 5.36; P=.0041), previous systemic therapy status (0-1 vs >1; HR, 3.52; P=.0217), and BED <115 Gy (HR, 3.45; P=.0254). Dose received by 99% of the target volume was the strongest dosimetric predictor for LC. Upon multivariate analysis, dose received by 99% of the target volume greater than BED of 98.7 Gy and systemic therapy status remained significant (HR, 0.12 and 3.64, with P=.0014 and P=.0472, respectively). Acute and late grade 3 toxicities attributed to SAbR were observed in 3 patients (1.7%) and 5 patients (2.9%), respectively. Conclusions: SAbR demonstrated excellent LC of metastatic renal cell carcinoma with a favorable safety profile when an adequate dose

High LET Radiation Can Enhance TGF(Beta) Induced EMT and Cross-Talk with ATM Pathways

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Wang, Minli; Hada, Megumi; Huff, Janice; Pluth, Janice M.; Anderson, Janniffer; ONeill, Peter; Cucinotta, Francis A.

2010-01-01

The TGF(Beta) pathway has been shown to regulate or directly interact with the ATM pathway in the response to radiation in mammary epithelial cells. We investigated possible interactions between the TGF(Beta) and ATM pathways following simulated space radiation using hTERT immortalized human esophageal epithelial cells (EPC-hTERT), mink lung epithelial cells (Mv1lu), and several human fibroblast cell lines. TGF(Beta) is a key modulator of the Epithelial-Mesenchymal Transition (EMT), important in cancer progression and metastasis. The implication of EMT by radiation also has several lines of developing evidence, however is poorly understood. The identification of TGF(Beta) induced EMT can be shown in changes to morphology, related gene over expression or down regulation, which can be detected by RT-PCR, and immunostaining and western blotting. In this study, we have observed morphologic and molecular alternations consistent with EMT after Mv1lu cells were treated with TGF(Beta) High LET radiation enhanced TGF(Beta) mediated EMT with a dose as low as 0.1Gy. In order to consider the TGF(Beta) interaction with ATM we used a potent ATM inhibitor Ku55933 and investigated gene expression changes and Smad signaling kinetics. Ku559933 was observed to reverse TGF(Beta) induced EMT, while this was not observed in dual treated cells (radiation+TGF(Beta)). In EPC-hTERT cells, TGF(Beta) alone was not able to induce EMT after 3 days of application. A combined treatment with high LET, however, significantly caused the alteration of EMT markers. To study the function of p53 in the process of EMT, we knocked down P53 through RNA interference. Morphology changes associated with EMT were observed in epithelial cells with silenced p53. Our study indicates: high LET radiation can enhance TGF(Beta) induced EMT; while ATM is triggering the process of TGF(Beta)-induced EMT, p53 might be an essential repressor for EMT phenotypes.

Ionizing radiation effect on enzymes. II

International Nuclear Information System (INIS)

Libicky, A.; Fidlerova, J.; Urban, J.; Chottova, O.; Kubankova, V.

1980-01-01

The effects of gamma radiation on the efficacy of chymotrypsin in pancreatin prepared by the separation of enzymes from an activated pancreas extract, in the same sample in which the content of lipids was increased to 16.55%, and in pancreatin prepared by drying an incompletely activated ground pancreas were compared with the effect of radiation on crystaline lyophilized chymotrypsin. The working conditions were identical with those described in the previous communication, all samples possessed nearly identical humidity on irradiation. The efficacy of chymotrypsin was determined by the method of PhBs 3, ethyl ester L-tyrosine hydrochloride being used as the substrate. The results were statistically evaluated and after calculation for dried lipid-free substance represented in graphs. The sequence of the loss of efficacy in pancreatin corresponded to the sequence of the loss of the total proteolytic efficacy found in the previous communication. The lowest remaining efficacy was found in crystalline lyophilized chymotrypsin. Percent losses of chymotrypsin efficacy in pancreatin determined by the synthetic substrate were in good agreement with the loss of the total proteolytic efficacy of the same samples determined by casein. (author)

Efficacy of post operative adjuvant therapy with human interferon beta, MCNU and radiation (IMR) for malignant glioma: comparison among three protocols

International Nuclear Information System (INIS)

Hatano, N.; Wakabayashi, T.; Kajita, Y.; Mizuno, M.; Ohno, T.; Nakayashiki, N.; Takemura, A.; Yoshida, J.

2000-01-01

In order to develop ultimate adjuvant therapy for malignant gliomas, we analyzed 77 patients with malignant gliomas (29 anaplastic astrocytomas (AAs) and 48 glioblastoma multiformes (GMs)) treated by three protocols of IMR therapy (human interferon-beta (HuIFN-β), MCNU and radiation). In protocol 1 (n = 45 : AA = 13, GM = 32), 1 x 10 6 IU of HuIFN-β was administrated intravenously once a day for 7 days. On day 2, MCNU was administrated at a dose of 2 mg/kg b.w. intravenously and from day 3, radiation was started in five weekly fractions of 2 Gy for 6 weeks. Total dose was 60 Gy. Protocol 2 (n = 19 : AA = 11, GM = 8) was comparable with protocol 1 except HuIFN-β was administrated twice a day at a dose of 1 x 10 6 IU each. Protocol 3 (n = 13 : AA = 5, GM = 8) differed from protocol 2 only in a high dose-hyperfractionated radiation which was given twice a day at a dose of 1.5 Gy each and for a total dose of 66 Gy. Antitumor effects were evaluated by survival and response rate determined by decrease of tumor size. Significant improvement was obtained in patients with AAs by protocol 2 and 3. Response rates of patients with AAs and GMs were 46.2 % and 50 % in protocol 1, 63.6 % and 50 % in protocol 2, and 80 % and 50 % in protocol 3, respectively. One and two year survival rates in AAs were 46.4 % and 34.8 % in protocol 1, both 75 % in protocol 2, and both 100 % in protocol 3. Survival rates in GMs were not different among them. Except of radiation necrosis, which was observed in 38.5 % of the patients under protocol 3, there was no significant difference in the adverse effects among the three protocols. In the present study, the efficacy of IMR therapy for patients with malignant gliomas, especially for AAs, was confirmed. We conclude that twice a day administrations of HuIFN-β in combination with a high dose-hyperfractionated radiation provide increased efficacy in IMR therapy. (author)

Poly-epsilon-caprolactone nanoparticles enhance ursolic acid in vivo efficacy against Trypanosoma cruzi infection.

Science.gov (United States)

Abriata, Juliana Palma; Eloy, Josimar O; Riul, Thalita Bachelli; Campos, Patricia Mazureki; Baruffi, Marcelo Dias; Marchetti, Juliana Maldonado

2017-08-01

Despite affecting millions of people worldwide, Chagas disease is still neglected by the academia and industry and the therapeutic option available, benznidazole, presents limited efficacy and side effects. Within this context, ursolic acid may serve as an option for treatment, however has low bioavailability, which can be enhanced through the encapsulation in polymeric nanoparticles. Therefore, herein we developed ursolic acid-loaded nanoparticles with poly-ε-caprolactone by the nanoprecipitation method and characterized them for particle size, zeta potential, polydispersity, encapsulation efficiency, morphology by scanning electron microscopy and thermal behavior by differential scanning calorimetry. Results indicated that an appropriate ratio of organic phase/aqueous phase and polymer/drug is necessary to produce smaller particles, with low polydispersity, negative zeta potential and high drug encapsulation efficiency. In vitro studies indicated the safety of the formulation against fibroblast culture and its efficacy in killing T. cruzi. Very importantly, the in vivo study revealed that the ursolic acid-loaded nanoparticle is as potent as the benznidazole group to control parasitemia, which could be attributed to improved bioavailability of the encapsulated drug. Finally, the toxicity evaluation showed that while benznidazole group caused liver toxicity, the nanoparticles were safe, indicating that this formulation is promising for future evaluation. Copyright © 2017 Elsevier B.V. All rights reserved.

Economic impact and effectiveness of radiation protection measures in aviation during a ground level enhancement

Directory of Open Access Journals (Sweden)

Matthiä Daniel

2015-01-01

Full Text Available In addition to the omnipresent irradiation from galactic cosmic rays (GCR and their secondary products, passengers and aircraft crew may be exposed to radiation from solar cosmic rays during ground level enhancements (GLE. In general, lowering the flight altitude and changing the flight route to lower latitudes are procedures applicable to immediately reduce the radiation exposure at aviation altitudes. In practice, however, taking such action necessarily leads to modifications in the flight plan and the consequential, additional fuel consumption constrains the mitigating measures. In this work we investigate in a case study of the ground level event of December 13th 2006 how potential mitigation procedures affect the total radiation exposure during a transatlantic flight from Seattle to Cologne taking into account constraints concerning fuel consumption and range.

Efficacy of a radiation safety education initiative in reducing radiation exposure in the pediatric IR suite

International Nuclear Information System (INIS)

Sheyn, David D.; Racadio, John M.; Patel, Manish N.; Racadio, Judy M.; Johnson, Neil D.; Ying, Jun

2008-01-01

The use of ionizing radiation is essential for diagnostic and therapeutic imaging in the interventional radiology (IR) suite. As the complexity of procedures increases, radiation exposure risk increases. We believed that reinforcing staff education and awareness would help optimize radiation safety. To evaluate the effect of a radiation safety education initiative on IR staff radiation safety practices and patient radiation exposure. After each fluoroscopic procedure performed in the IR suite during a 4-month period, dose-area product (DAP), fluoroscopy time, and use of shielding equipment (leaded eyeglasses and hanging lead shield) by IR physicians were recorded. A lecture and article were then given to IR physicians and technologists that reviewed ALARA principles for optimizing radiation dose. During the following 4 months, those same parameters were recorded after each procedure. Before education 432 procedures were performed and after education 616 procedures were performed. Physician use of leaded eyeglasses and hanging shield increased significantly after education. DAP and fluoroscopy time decreased significantly for uncomplicated peripherally inserted central catheters (PICC) procedures and non-PICC procedures after education, but did not change for complicated PICC procedures. Staff radiation safety education can improve IR radiation safety practices and thus decrease exposure to radiation of both staff and patients. (orig.)

RAD9 deficiency enhances radiation induced bystander DNA damage and transcriptomal response

International Nuclear Information System (INIS)

Ghandhi, Shanaz A; Ponnaiya, Brian; Panigrahi, Sunil K; Hopkins, Kevin M; Cui, Qingping; Hei, Tom K; Amundson, Sally A; Lieberman, Howard B

2014-01-01

Radiation induced bystander effects are an important component of the overall response of cells to irradiation and are associated with human health risks. The mechanism responsible includes intra-cellular and inter-cellular signaling by which the bystander response is propagated. However, details of the signaling mechanism are not well defined. We measured the bystander response of Mrad9 +/+ and Mrad9 −/− mouse embryonic stem cells, as well as human H1299 cells with inherent or RNA interference-mediated reduced RAD9 levels after exposure to 1 Gy α particles, by scoring chromosomal aberrations and micronuclei formation, respectively. In addition, we used microarray gene expression analyses to profile the transcriptome of directly irradiated and bystander H1299 cells. We demonstrated that Mrad9 null enhances chromatid aberration frequency induced by radiation in bystander mouse embryonic stem cells. In addition, we found that H1299 cells with reduced RAD9 protein levels showed a higher frequency of radiation induced bystander micronuclei formation, compared with parental cells containing inherent levels of RAD9. The enhanced bystander response in human cells was associated with a unique transcriptomic profile. In unirradiated cells, RAD9 reduction broadly affected stress response pathways at the mRNA level; there was reduction in transcript levels corresponding to genes encoding multiple members of the UVA-MAPK and p38MAPK families, such as STAT1 and PARP1, suggesting that these signaling mechanisms may not function optimally when RAD9 is reduced. Using network analysis, we found that differential activation of the SP1 and NUPR1 transcriptional regulators was predicted in directly irradiated and bystander H1299 cells. Transcription factor prediction analysis also implied that HIF1α (Hypoxia induced factor 1 alpha) activation by protein stabilization in irradiated cells could be a negative predictor of the bystander response, suggesting that local hypoxic stress

Electron flux enhancement in the inner radiation belt during moderate magnetic storms

Directory of Open Access Journals (Sweden)

H. Tadokoro

2007-06-01

Full Text Available During moderate magnetic storms, an electron channel (300–1100 keV of the NOAA satellite has shown sudden electron flux enhancements in the inner radiation belt. After examinating the possibility of contamination by different energetic particles, we conclude that these electron flux enhancements are reliable enough to be considered as natural phenomena, at least for the cases of small to moderate magnetic storms. Here, we define small and moderate storms to be those in which the minimum Dst ranges between −30 and −100 nT. The electron flux enhancements appear with over one order of magnitude at L~2 during these storms. The enhancement is not accompanied by any transport of electron flux from the outer belt. Statistical analysis shows that these phenomena have a duration of approximately 1 day during the period, starting with the main phase to the early recovery phase of the storms. The flux enhancement shows a dawn-dusk asymmetry; the amount of increased flux is larger in the dusk side. We suggest that this phenomenon could not be caused by the radial diffusion but would be due to pitch-angle scattering at the magnetic equator. The inner belt is not in a stationary state, as was previously believed, but is variable in response to the magnetic activity.

Estimation of tumour dose enhancement due to gold nanoparticles during typical radiation treatments: a preliminary Monte Carlo study

International Nuclear Information System (INIS)

Cho, S H

2005-01-01

A recent mice study demonstrated that gold nanoparticles could be safely administered and used to enhance the tumour dose during radiation therapy. The use of gold nanoparticles seems more promising than earlier methods because of the high atomic number of gold and because nanoparticles can more easily penetrate the tumour vasculature. However, to date, possible dose enhancement due to the use of gold nanoparticles has not been well quantified, especially for common radiation treatment situations. Therefore, the current preliminary study estimated this dose enhancement by Monte Carlo calculations for several phantom test cases representing radiation treatments with the following modalities: 140 kVp x-rays, 4 and 6 MV photon beams, and 192 Ir gamma rays. The current study considered three levels of gold concentration within the tumour, two of which are based on the aforementioned mice study, and assumed either no gold or a single gold concentration level outside the tumour. The dose enhancement over the tumour volume considered for the 140 kVp x-ray case can be at least a factor of 2 at an achievable gold concentration of 7 mg Au/g tumour assuming no gold outside the tumour. The tumour dose enhancement for the cases involving the 4 and 6 MV photon beams based on the same assumption ranged from about 1% to 7%, depending on the amount of gold within the tumour and photon beam qualities. For the 192 Ir cases, the dose enhancement within the tumour region ranged from 5% to 31%, depending on radial distance and gold concentration level within the tumour. For the 7 mg Au/g tumour cases, the loading of gold into surrounding normal tissue at 2 mg Au/g resulted in an increase in the normal tissue dose, up to 30%, negligible, and about 2% for the 140 kVp x-rays, 6 MV photon beam, and 192 Ir gamma rays, respectively, while the magnitude of dose enhancement within the tumour was essentially unchanged. (note)

Efficacy of the RADPAD Protection Drape in Reducing Operators' Radiation Exposure in the Catheterization Laboratory: A Sham-Controlled Randomized Trial.

Science.gov (United States)

Vlastra, Wieneke; Delewi, Ronak; Sjauw, Krischan D; Beijk, Marcel A; Claessen, Bimmer E; Streekstra, Geert J; Bekker, Robbert J; van Hattum, Juliette C; Wykrzykowska, Joanna J; Vis, Marije M; Koch, Karel T; de Winter, Robbert J; Piek, Jan J; Henriques, José P S

2017-11-01

Interventional cardiologists are increasingly exposed to radiation-induced diseases like cataract and the stochastic risk of left-sided brain tumors. The RADPAD is a sterile, disposable, lead-free shield placed on the patient with the aim to minimize operator-received scatter radiation. The objective of the trial was to examine the RADPAD's efficacy in a real-world situation. In the current, double-blind, sham-controlled, all-comer trial, patients undergoing diagnostic catheterization or percutaneous coronary interventions were randomized in a 1:1:1 ratio to a radiation absorbing shield (RADPAD), standard treatment (NOPAD), or a sham shield (SHAMPAD). The sham shield allowed testing for shield-induced radiation behavior. The primary outcome was the difference in relative exposure of the primary operator between the RADPAD and NOPAD arms and was defined as the ratio between operator's exposure (E in µSv) and patient exposure (dose area product in mGy·cm 2 ), measured per procedure. A total of 766 consecutive coronary procedures were randomized to the use of RADPAD (N=255), NOPAD (N=255), or SHAMPAD (N=256). The use of RADPAD was associated with a 20% reduction in relative operator exposure compared with that of NOPAD ( P =0.01) and a 44% relative exposure reduction compared with the use of a SHAMPAD ( P RADPAD radiation shield reduced operator radiation exposure compared with procedures with NOPAD or SHAMPAD. This study supports the routine use of RADPAD in the catheterization laboratory. URL: https://www.clinicaltrials.gov. Unique identifier: NCT03139968. © 2017 American Heart Association, Inc.

Photostabilization of doxorubicin hydrochloride with radioprotective and photoprotective agents: Potential mechanism for enhancing chemotherapy during radiotherapy

International Nuclear Information System (INIS)

Habib, M.J.; Asker, A.F.

1989-01-01

p-Aminobenzoic acid (PABA), urocanic acid, and sodium urate were found to significantly enhance the photostability of doxorubicin hydrochloride [adriamycin, (ADR)]. d1-Methionine, thiourea, and glycine also increased the photostability of this drug, but to a lesser degree. Sodium thiosulfate on the other hand, was found to be detrimental to the photostability of ADR. The photostabilizing effect of PABA was found to increase with increase of its concentration and was influenced by the pH and the buffer species of the vehicle. The findings would have an impact on the enhancement of therapeutic efficacy of adriamycin when administered during radiation therapy

Probe And Enhancement Of SBS Based Phonons In Infrared Fibers Using Waveguide Coupled External Radiation

Science.gov (United States)

Yu, Chung; Chong, Yat C.; Fong, Chee K.

1989-06-01

Interaction of GHz and MHz radiation with CO2 laser propagation in a silver halide fiber using sBs based phonon coupling is furthet investigated. The external signal serves to both probe and enhance laser generated sBs phonons in the fiber. Efficient coupling of microwave radiation into the fiber is accomplished by placing the fiber in a hollow metallic waveguide, designed and constructed to transmit the dominant mode in the 0.9-2.0 GHz band. MHz radiation is conveniently coupled into the fiber using the guided microwave radiation as carrier. Phonon emissions from the fiber under CO2 laser pumping are first established on a spectrum analyzer; low frequency generators ale then tuned to match these frequencies and their maximum interaction recorded. Such interactions are systematically studied by monitoring the amplitude and waveform of the reflected and transmitted laser pulse at various power levels and frequencies of the externally coupled radiation. A plot of reflected laser power versus incident laser power reveals a distinct sBs generated phonon threshold. Variouslaunch directions of the GHz and MHz radiation with respect to the direction of laser propagation are realized to verify theory governing sBs interactions. The MHz radiation and its associated phonons in the fiber are convenient tools for probing sBs related phenomenon in infrared fibers.

The increased use of radiation requires enhanced activities regarding radiation safety control

International Nuclear Information System (INIS)

Lee, Yun Jong; Lee, Jin Woo; Jeong, Gyo Seong

2015-01-01

More recently, companies that have obtained permission to use radioactive materials or radiation device and registered radiation workers have increased by 10% and 4% respectively. The increased use of radiation could have an effect on radiation safety control. However, there is not nearly enough manpower and budget compared to the number of workers and facilities. This paper will suggest a counteroffer thought analyzing pending issues. The results of this paper indicate that there are 47 and 31.3 workers per radiation protection officer in educational and research institutes, respectively. There are 20.1 persons per RPO in hospitals, even though there are 2 RPOs appointed. Those with a special license as a radioisotope handler were ruled out as possible managers because medical doctors who have a special license for radioisotope handling normally have no experience with radiation safety. The number of staff members and budget have been insufficient for safety control at most educational and research institutes. It is necessary to build an optimized safety control system for effective Radiation Safety Control. This will reduce the risk factor of safety, and a few RPOs can be supplied for efficiency and convenience

The increased use of radiation requires enhanced activities regarding radiation safety control

Energy Technology Data Exchange (ETDEWEB)

Lee, Yun Jong; Lee, Jin Woo; Jeong, Gyo Seong [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2015-05-15

More recently, companies that have obtained permission to use radioactive materials or radiation device and registered radiation workers have increased by 10% and 4% respectively. The increased use of radiation could have an effect on radiation safety control. However, there is not nearly enough manpower and budget compared to the number of workers and facilities. This paper will suggest a counteroffer thought analyzing pending issues. The results of this paper indicate that there are 47 and 31.3 workers per radiation protection officer in educational and research institutes, respectively. There are 20.1 persons per RPO in hospitals, even though there are 2 RPOs appointed. Those with a special license as a radioisotope handler were ruled out as possible managers because medical doctors who have a special license for radioisotope handling normally have no experience with radiation safety. The number of staff members and budget have been insufficient for safety control at most educational and research institutes. It is necessary to build an optimized safety control system for effective Radiation Safety Control. This will reduce the risk factor of safety, and a few RPOs can be supplied for efficiency and convenience.

Superselective Particle Embolization Enhances Efficacy of Radiofrequency Ablation: Effects of Particle Size and Sequence of Action

International Nuclear Information System (INIS)

Tanaka, Toshihiro; Isfort, Peter; Braunschweig, Till; Westphal, Saskia; Woitok, Anna; Penzkofer, Tobias; Bruners, Philipp; Kichikawa, Kimihiko; Schmitz-Rode, Thomas; Mahnken, Andreas H.

2013-01-01

Purpose. To evaluate the effects of particle size and course of action of superselective bland transcatheter arterial embolization (TAE) on the efficacy of radiofrequency ablation (RFA). Methods. Twenty pigs were divided into five groups: group 1a, 40-μm bland TAE before RFA; group 1b, 40-μm bland TAE after RFA; group 2a, 250-μm bland TAE before RFA; group 2b, 250-μm bland TAE after RFA and group 3, RFA alone. A total of 40 treatments were performed with a combined CT and angiography system. The sizes of the treated zones were measured from contrast-enhanced CTs on days 1 and 28. Animals were humanely killed, and the treated zones were examined pathologically. Results. There were no complications during procedures and follow-up. The short-axis diameter of the ablation zone in group 1a (mean ± standard deviation, 3.19 ± 0.39 cm) was significantly larger than in group 1b (2.44 ± 0.52 cm; P = 0.021), group 2a (2.51 ± 0.32 cm; P = 0.048), group 2b (2.19 ± 0.44 cm; P = 0.02), and group 3 (1.91 ± 0.55 cm; P 3 ). At histology, 40-μm microspheres were observed to occlude smaller and more distal arteries than 250-μm microspheres. Conclusion. Bland TAE is more effective before RFA than postablation embolization. The use of very small 40-μm microspheres enhances the efficacy of RFA more than the use of larger particles.

Improvement of boiling heat transfer by radiation induced boiling enhancement

International Nuclear Information System (INIS)

Imai, Yasuyuki; Okamoto, Koji; Madarame, Haruki; Takamasa, Tomoji

2003-01-01

For nuclear reactor systems, the critical heat flux (CHF) data is very important because it limits reactor efficiency. Improvement of CHF requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. In our previous study, we confirmed that the surface wettability changed significantly or that highly hydrophilic conditions were achieved, after irradiation of 60 Co gamma ray, by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of RISA on boiling phenomena, surface wettability in a high-temperature environment and critical heat flux (CHF) of metal oxides irradiated by gamma rays were investigated. A CHF experiment in the pool boiling condition was carried out under atmospheric pressure. The heating test section made of titanium was 0.2 mm in thickness, 3 mm in height, and 60 mm in length. Oxidation of the surface was carried out by plasma jetting for 40 seconds. The test section was irradiated by 60 Co gamma ray with predetermined radiation intensity and period. The CHF of oxidized titanium was improved up to 100 percent after 800 kGy 60 Co gamma ray irradiation. We call this effect Radiation Induced Boiling Enhancement (RIBE). Before we conducted the CHF experiment, contact angles of the test pieces were measured to show the relationship between wettability and CHF. The CHF in the present experiment increases will surface wettability in the same manner as shown by Liaw and Dhir's results. (author)

Improvement of boiling heat transfer by radiation induced boiling enhancement

International Nuclear Information System (INIS)

Imai, Y.; Okamoto, K.; Madarame, H.; Takamasa, T.

2003-01-01

For nuclear reactor systems, the Critical Heat Flux (CHF) data is very important because it limits reactor efficiency. Improvement of CHF requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. In our previous study, we confirmed that the surface wettability changed significantly or that highly hydrophilic conditions were achieved, after irradiation of 60Co gamma ray, by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of RISA on boiling phenomena, surface wettability in a high-temperature environment and Critical Heat Flux (CHF) of metal oxides irradiated by gamma rays were investigated. A CHF experiment in the pool boiling condition was carried out under atmospheric pressure. The heating test section made of titanium was 0.2mm in thickness, 3mm in height, and 60mm in length. Oxidation of the surfaces was carried out by plasma jetting for 40 seconds. The test section was irradiated by 60Co gamma ray with predetermined radiation intensity and period. The CHF of oxidized titanium was improved up to 100 percent after 800kGy 60Co gamma ray irradiation. We call this effect Radiation Induced Boiling Enhancement (RIBE). Before we conducted the CHF experiment, contact angles of the test pieces were measured to show the relationship between wettability and CHF. The CHF in the present experiment increases with surface wettability in the same manner as shown by Liaw and Dhir's results

Endostatin improves radioresponse and blocks tumor revascularization after radiation therapy for A431 xenografts in mice

International Nuclear Information System (INIS)

Itasaka, Satoshi; Komaki, Ritsuko; Herbst, Roy S.; Shibuya, Keiko; Shintani, Tomoaki D.D.S.; Hunter, Nancy R. M.S.; Onn, Amir; Bucana, Corazon D.; Milas, Luka; Ang, K. Kian; O'Reilly, Michael S.

2007-01-01

Purpose: Clinical trials of antiangiogenic agents used alone for advanced malignancy have been disappointing but preclinical studies suggest that the addition of radiation therapy could improve antitumor efficacy. To test the hypothesis that antiangiogenic therapy combined with radiation therapy can overcome the limitations of antiangiogenic monotherapy, we studied the effects of endostatin combined with radiation on the growth and vascularization of A431 human epidermoid carcinomas growing intramuscularly in the legs of mice. Methods and Materials: Mice with established A431 human epidermoid leg tumors were treated with radiation, endostatin, both radiation and endostatin, or vehicle control. The experiment was repeated and mice from each group were killed at 2, 7, and 10 days after irradiation so that tumor tissue could be obtained to further analyze the kinetics of the antitumor, antivascular, and antiangiogenic response to therapy. Results: Endostatin enhanced the antitumor effects of radiation, and prolonged disease-free survival was observed in the combined treatment group. Endothelial cell proliferation was increased in tumors after irradiation but was blocked by the concurrent administration of endostatin, and the combination of endostatin with radiation enhanced endothelial cell apoptosis within 48 h after irradiation. Expression of vascular endothelial growth factor, interleukin-8, and matrix metalloproteinase-2 were increased in tumors after irradiation, and this increase was blocked by concurrent administration of endostatin. Conclusion: These data indicate that endostatin can block tumor revascularization after radiation therapy and thereby augment radioresponse

Radioactivity levels in Indian coal and some technologically enhanced exposure to natural radiation environment of India

International Nuclear Information System (INIS)

Ramachandran, T.V.; Mishra, U.C.

1988-01-01

The summary of results of gamma-spectrometric measurements of natural radioactivity levels in coal from mines, coal, fly-ash, slag and soil samples from thermal power plants in India are presented. These constitute the sources of technologic ally enhanced exposures to natural radiation. Brief description of sampling and measurement procedure is given. Radiation dose to the population from coal fired power plants for electricity generation have been calculated using the model developed by UNSCEAR and ORNL reports with correction for local population density. (author). 13 refs., 7 tabs., 8 figs

Theory and simulations of radiation friction induced enhancement of laser-driven longitudinal fields

Science.gov (United States)

Gelfer, E. G.; Fedotov, A. M.; Weber, S.

2018-06-01

We consider the generation of a quasistatic longitudinal electric field by intense laser pulses propagating in a transparent plasma with radiation friction (RF) taken into account. For both circular and linear polarization of the driving pulse we develop a 1D analytical model of the process, which is valid in a wide range of laser and plasma parameters. We define the parameter region where RF results in an essential enhancement of the longitudinal field. The amplitude and the period of the generated longitudinal wave are estimated and optimized. Our theoretical predictions are confirmed by 1D and 2D PIC simulations. We also demonstrate numerically that RF should substantially enhance the longitudinal field generated in a plasma by a 10 PW laser such as ELI Beamlines.

Cordycepin enhances Epstein-Barr virus lytic infection and Epstein-Barr virus-positive tumor treatment efficacy by doxorubicin.

Science.gov (United States)

Du, Yinping; Yu, Jieshi; Du, Li; Tang, Jun; Feng, Wen-Hai

2016-07-01

The consistent latent presence of Epstein-Barr virus (EBV) in tumor cells offers potential for virus-targeted therapies. The switch from the latent form of EBV to the lytic form in tumor cells can lead to tumor cell lysis. In this study, we report that a natural small molecule compound, cordycepin, can induce lytic EBV infection in tumor cells. Subsequently, we demonstrate that cordycepin can enhance EBV reactivating capacity and EBV-positive tumor cell killing ability of low dose doxorubicin. The combination of cordycepin and doxorubicin phosphorylates CCAAT/enhancer binding protein β (C/EBPβ) through protein kinase C (PKC)-p38 mitogen activated protein kinases (p38 MAPK) signaling pathway, and C/EBPβ is required for the activation of lytic EBV infection. Most importantly, an in vivo experiment demonstrates that the combination of cordycepin and doxorubicin is more effective in inhibiting tumor growth in SCID mice than is doxorubicin alone. Our findings establish that cordycepin can enhance the efficacy of conventional chemotherapy for treatment of EBV-positive tumors. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effects of Self-Regulated Vocabulary Learning Process on Self-Efficacy

Science.gov (United States)

Mizumoto, Atsushi

2013-01-01

Researchers, especially in the field of educational psychology, have argued that self-efficacy plays an important role in self-regulated learning. As such, teaching of self-regulated learning often focuses on enhancing self-efficacy. However, few studies have examined how the process of self-regulated learning might lead to the enhancement of…

beta 1 integrin inhibition dramatically enhances radiotherapy efficacy in human breast cancer xenografts

International Nuclear Information System (INIS)

Park, Catherine C.; Park, Catherine C.; Zhang, Hui J.; Yao, Evelyn S.; Park, Chong J.; Bissell, Mina J.

2008-01-01

β1 integrin signaling has been shown to mediate cellular resistance to apoptosis after exposure to ionizing radiation (IR). Other signaling molecules that increase resistance include Akt, which promotes cell survival downstream of β1 integrin signaling. We showed previously that β1 integrin inhibitory antibodies, AIIB2, enhance apoptosis and decrease growth in human breast cancer cells in 3 dimensional laminin-rich extracellular matrix (3D lrECM) cultures and in vivo. Here we asked whether AIIB2 could synergize with IR to modify Akt-mediated IR resistance. We used 3D lrECM cultures to test the optimal combination of AIIB2 with IR treatment of two breast cancer cell lines, MCF-7 and HMT3522-T4-2, as well as T4-2 myr-Akt breast cancer colonies or HMT3522-S-1, which form normal organotypic structures in 3D lrECM. Colonies were assayed for apoptosis and β1 integrin/Akt signaling pathways were evaluated using western blot. In addition, mice bearing MCF-7 xenografts were used to validate the findings in 3D lrECM. We report that AIIB2 increased apoptosis optimally post-IR by down regulating Akt in breast cancer colonies in 3D lrECM. In vivo, addition of AIIB2 after IR significantly enhanced tumor growth inhibition and apoptosis compared to either treatment alone. Remarkably, the degree of tumor growth inhibition using AIIB2 plus 2 Gy radiation was similar to that of 8 Gy alone. We showed previously that AIIB2 had no discernible toxicity in mice; here, its addition allowed for a significant reduction in the IR dose that was necessary to achieve comparable growth inhibition and apoptosis in breast cancer xenografts in vivo

beta 1 integrin inhibition dramatically enhances radiotherapy efficacy in human breast cancer xenografts

Energy Technology Data Exchange (ETDEWEB)

Park, Catherine C.; Park, Catherine C.; Zhang, Hui J.; Yao, Evelyn S.; Park, Chong J.; Bissell, Mina J.

2008-06-02

{beta}1 integrin signaling has been shown to mediate cellular resistance to apoptosis after exposure to ionizing radiation (IR). Other signaling molecules that increase resistance include Akt, which promotes cell survival downstream of {beta}1 integrin signaling. We showed previously that {beta}1 integrin inhibitory antibodies, AIIB2, enhance apoptosis and decrease growth in human breast cancer cells in 3 dimensional laminin-rich extracellular matrix (3D lrECM) cultures and in vivo. Here we asked whether AIIB2 could synergize with IR to modify Akt-mediated IR resistance. We used 3D lrECM cultures to test the optimal combination of AIIB2 with IR treatment of two breast cancer cell lines, MCF-7 and HMT3522-T4-2, as well as T4-2 myr-Akt breast cancer colonies or HMT3522-S-1, which form normal organotypic structures in 3D lrECM. Colonies were assayed for apoptosis and {beta}1 integrin/Akt signaling pathways were evaluated using western blot. In addition, mice bearing MCF-7 xenografts were used to validate the findings in 3D lrECM. We report that AIIB2 increased apoptosis optimally post-IR by down regulating Akt in breast cancer colonies in 3D lrECM. In vivo, addition of AIIB2 after IR significantly enhanced tumor growth inhibition and apoptosis compared to either treatment alone. Remarkably, the degree of tumor growth inhibition using AIIB2 plus 2 Gy radiation was similar to that of 8 Gy alone. We showed previously that AIIB2 had no discernible toxicity in mice; here, its addition allowed for a significant reduction in the IR dose that was necessary to achieve comparable growth inhibition and apoptosis in breast cancer xenografts in vivo.

Adaptive response to ionizing radiation in normal human skin fibroblasts. Enhancement of DNA repair rate and modulation of gene expression

International Nuclear Information System (INIS)

Toledo, S.M. de; Mitchel, R.E.J.; Azzam, E.; Ottawa Univ., ON; Raaphorst, G.P.

1994-01-01

Low doses and dose rates of ionizing radiation enhance the rate of DNA repair in human fibroblasts and protect the cells against radiation-induced micronucleus formation. Chronic exposures reduce the mRNA levels of the genes topoisomerase II and FACC-1 (Fanconi's anemia, group C). (authors). 11 refs., 1 tab., 2 figs

Dynamic contrast-enhanced magnetic resonance imaging of radiation therapy-induced microcirculation changes in rectal cancer

International Nuclear Information System (INIS)

Lussanet, Quido G. de; Backes, Walter H.; Griffioen, Arjan W.; Padhani, Anwar R.; Baeten, Coen I.; Baardwijk, Angela van; Lambin, Philippe; Beets, Geerard L.; Engelshoven, Jos van; Beets-Tan, Regina G.H.

2005-01-01

Purpose: Dynamic contrast-enhanced T1-weighted magnetic resonance imaging (DCE-MRI) allows noninvasive evaluation of tumor microvasculature characteristics. This study evaluated radiation therapy related microvascular changes in locally advanced rectal cancer by DCE-MRI and histology. Methods and Materials: Dynamic contrast-enhanced-MRI was performed in 17 patients with primary rectal cancer. Seven patients underwent 25 fractions of 1.8 Gy radiation therapy (RT) (long RT) before DCE-MRI and 10 did not. Of these 10, 3 patients underwent five fractions of 5 Gy RT (short RT) in the week before surgery. The RT treated and nontreated groups were compared in terms of endothelial transfer coefficient (K PS , measured by DCE-MRI), microvessel density (MVD) (scored by immunoreactivity to CD31 and CD34), and tumor cell and endothelial cell proliferation (scored by immunoreactivity to Ki67). Results: Tumor K PS was 77% (p = 0.03) lower in the RT-treated group. Histogram analyses showed that RT reduced both magnitude and intratumor heterogeneity of K PS (p = 0.01). MVD was significantly lower (37%, p 0.03) in tumors treated with long RT than in nonirradiated tumors, but this was not the case with short RT. Endothelial cell proliferation was reduced with short RT (81%, p = 0.02) just before surgery, but not with long RT (p > 0.8). Tumor cell proliferation was reduced with both long (57%, p PS values showed significant radiation therapy related reductions in microvessel blood flow in locally advanced rectal cancer. These findings may be useful in evaluating effects of radiation combination therapies (e.g., chemoradiation or RT combined with antiangiogenesis therapy), to account for effects of RT alone

Enhanced antitumor efficacy of doxorubicin-encapsulated halloysite nanotubes

Directory of Open Access Journals (Sweden)

Li K

2017-12-01

Full Text Available Kai Li,1,* Yongxing Zhang,2,* Mengting Chen,1 Yangyang Hu,1 Weiliang Jiang,1 Li Zhou,1 Sisi Li,1 Min Xu,1 Qinghua Zhao,2 Rong Wan1 1Department of Gastroenterology, Shanghai First People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China; 2Department of Orthopaedics, Shanghai First People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: To improve the antitumor efficacy of doxorubicin (DOX and provide novel clinical treatment of gastric cancer, halloysite nanotubes (HNTs loaded with DOX were encapsulated by soybean phospholipid (LIP and the formed HNTs/DOX/LIP was systematically characterized via different techniques. The in vitro anticancer activity of HNTs/DOX/LIP was examined using an MTT assay. The antitumor efficacy and biocompatibility were monitored by measuring the tumor volume and assessing the blood routine and serum biochemistry using an ectopic implantation cancer model. The results show that when the concentration of HNTs was 3 mg/mL and the concentration of DOX was 1 mg/mL the optimal DOX loading efficiency was as high as 22.01%±0.43%. In vitro drug release behavior study demonstrated that HNTs/DOX/LIP shows a pH-responsive release property with fast drug release under acidic conditions (pH =5.4. MTT assays and in vivo experimental results revealed that HNTs/DOX/LIP exhibits a significantly higher inhibitory efficacy on the growth of mouse gastric cancer cells than free DOX at the same drug concentration. In addition, the life span of tumor-bearing mice in the HNTs/DOX/LIP-treated group was obviously prolonged compared with the control groups. Moreover, HNTs/DOX/LIP possessed excellent hemocompatibility as shown in the blood and histology studies. These findings indicated that the formed HNTs/DOX/LIP possesses higher antitumor efficacy and may be used as a targeted

Resveratrol sensitization of DU145 prostate cancer cells to ionizing radiation is associated to ceramide increase.

Science.gov (United States)

Scarlatti, Francesca; Sala, Giusy; Ricci, Clara; Maioli, Claudio; Milani, Franco; Minella, Marco; Botturi, Marco; Ghidoni, Riccardo

2007-08-08

Radiotherapy is an established therapeutic modality for prostate cancer. Since it is well known that radiotherapy is limited due to its severe toxicity towards normal cells at high dose and minimal effect at low dose, the search for biological compounds that increase the sensitivity of tumors cells to radiation may improve the efficacy of therapy. Resveratrol, a natural antioxidant, was shown to inhibit carcinogenesis in animal models, and to block the process of tumor initiation and progression. The purpose of this study was to examine whether or not resveratrol can sensitize DU145, an androgen-independent human prostate cancer cell line, to ionizing radiation. We report here that DU145 cells are resistant to ionizing radiation-induced cell death, but pretreatment with resveratrol significantly enhances cell death. Resveratrol acts synergistically with ionizing radiation to inhibit cell survival in vitro. Resveratrol also potentiates ionizing radiation-induced ceramide accumulation, by promoting its de novo biosynthesis. This confirms ceramide as an effective mediator of the anticancer potential induced by resveratrol.

Pretreatment of grass waste using combined ionizing radiation-acid treatment for enhancing fermentative hydrogen production.

Science.gov (United States)

Yang, Guang; Wang, Jianlong

2018-05-01

In this study, the combined ionizing radiation-acid pretreatment process was firstly applied to enhance hydrogen fermentation of grass waste. Results showed that the combined pretreatment synergistically enhanced hydrogen fermentation of grass waste. The SCOD and soluble polysaccharide contents of grass waste increased by 1.6 and 2.91 times after the combined pretreatment, respectively. SEM observation and crystallinity test showed the combined pretreatment effectively disrupted the grass structure. Owing to the more favorable substrate conditions, the hydrogen yield achieved 68 mL/g-dry grass added after the combined pretreatment, which was 161.5%, 112.5% and 28.3% higher than those from raw, ionizing radiation pretreated and acid pretreated grass waste, respectively. The VS removal also increased from 13.9% to 25.6% by the combined pretreatment. Microbial community analysis showed that the abundance of dominant hydrogen producing genus Clostridium sensu stricto 1 increased from 37.9% to 69.4% after the combined pretreatment, which contributed to more efficient hydrogen fermentation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Investigation of absorbed radiation dose in refraction-enhanced breast tomosynthesis by a Laue case analyser

International Nuclear Information System (INIS)

Sato, H.; Ando, M.; Shimao, D.

2011-01-01

An early diagnosis system for breast cancer using refraction-enhanced breast tomosynthesis is under development. Tomograms of breast specimens based on refraction-contrast were demonstrated using the simplest shift-and-add tomosynthesis algorithm. Raw projection image data of breast specimens for tomosynthesis were acquired for a total of 51 views over an angle of 50 deg., in increments of 1 deg., by rotating the object. The incident X ray was monochromatic synchrotron radiation with 20 keV. The purpose of this study was to estimate the absorbed dose of a new X-ray imaging method. As breast cancer almost always arises in glandular breast tissue, the average absorbed dose in such glandular tissue should be measured to estimate the radiation risk associated with mammography. The absorbed dose of the mammary gland due to monochromatic X rays was calculated by the Monte Carlo method, and the optimal X ray energy range for refraction-enhanced breast tomosynthesis was investigated through actual measurements. Compared with the conventional method, it was found to be below one-sixth per inspection. (authors)

Enhancement and Tunability of Near-Field Radiative Heat Transfer Mediated by Surface Plasmon Polaritons in Thin Plasmonic Films

Directory of Open Access Journals (Sweden)

Svetlana V. Boriskina

2015-06-01

Full Text Available The properties of thermal radiation exchange between hot and cold objects can be strongly modified if they interact in the near field where electromagnetic coupling occurs across gaps narrower than the dominant wavelength of thermal radiation. Using a rigorous fluctuational electrodynamics approach, we predict that ultra-thin films of plasmonic materials can be used to dramatically enhance near-field heat transfer. The total spectrally integrated film-to-film heat transfer is over an order of magnitude larger than between the same materials in bulk form and also exceeds the levels achievable with polar dielectrics such as SiC. We attribute this enhancement to the significant spectral broadening of radiative heat transfer due to coupling between surface plasmon polaritons (SPPs on both sides of each thin film. We show that the radiative heat flux spectrum can be further shaped by the choice of the substrate onto which the thin film is deposited. In particular, substrates supporting surface phonon polaritons (SPhP strongly modify the heat flux spectrum owing to the interactions between SPPs on thin films and SPhPs of the substrate. The use of thin film phase change materials on polar dielectric substrates allows for dynamic switching of the heat flux spectrum between SPP-mediated and SPhP-mediated peaks.

Safety and radiation-enhancing effect of sodium glycididazole in loco regionally advanced laryngeal cancers previously treated with platinum-containing chemotherapy regimens: a preliminary report

International Nuclear Information System (INIS)

Zeng, Y.C.; Wu, R.; Xu, Z.G.; Zhang, X.Y.; Wu, L.N.; Wang, Y.M.; Zheng, W.; Chen, X.D.; Chi, F.; Zhang, Z.Y.; Li, X.; Jin, X.Y.; Chen, W.; Wang, S.L.; Xiao, F.D.; Wang, E.Y.; Dong, X.Q.; Jia, M.X.; Li, Y.; Fan, G.L.; Hao, S.H.; Zhang, L.B.; Zhang, H.B.; Xia, H.H.X.

2010-01-01

Purpose: To determine the safety and radiation-enhancing effect of sodium glycididazole in laryngeal squamous cell carcinoma (stage T3-4,N0-3,M0) with conventional radiotherapy. Patients and methods: Patients with locoregional advanced laryngeal cancer (stage T3-4,N0-3,M0) were included: group 1(control, n = 30)were not administered of sodium glycididazole; group 2 (test, n = 30) received sodium glycididazole at a dose of 700 mg/m2 intravenous infusion 30 minutes before radiotherapy three times a week. Surrogate end-points of efficacy were tumor and nodal size. Safety parameters were vomiting, nausea, mucositis, laryngeal edema, esophagus and skin reaction, dysphagia, dyspnea, neurological deficit. Patients were evaluated weekly during treatment for 7 weeks and thereafter monthly for 3 months. Results: In the test, the overall response rate was 88.89% (95% CI, 71.00-97.00%) at 7 weeks and 92.59% (95% CI, 76.00 to 99.00%) at 1 month of follow-up. In the control, the overall response rate was 62.5% (95% CI, 41.00 to 81.00%) at 7 weeks and 58.33% (95% CI, 37.00 to 78.00%) at 1 month of follow-up. The short-term locoregional response rate was better in the test group at 7 weeks (p = 0.027) and at 1 month (p = 0.005) of follow-up. The test group had significantly more nausea and vomiting in weeks 1 (p = 0.047), 2 (p = 0.007), and 3 (p = 0.01) of treatment. Conclusions: The study indicates sodium glycididazole is an effective radiation-enhancing agent that improves short-term locoregional control and is well tolerated in patients with loco regionally advanced laryngeal cancer. (authors)

Efficacy Endpoints of Radiation Therapy Group Protocol 0247: A Randomized, Phase 2 Study of Neoadjuvant Radiation Therapy Plus Concurrent Capecitabine and Irinotecan or Capecitabine and Oxaliplatin for Patients With Locally Advanced Rectal Cancer

International Nuclear Information System (INIS)

Wong, Stuart J.; Moughan, Jennifer; Meropol, Neal J.; Anne, Pramila Rani; Kachnic, Lisa A.; Rashid, Asif; Watson, James C.; Mitchell, Edith P.; Pollock, Jondavid; Lee, R. Jeffrey; Haddock, Michael; Erickson, Beth A.; Willett, Christopher G.

2015-01-01

Purpose: To report secondary efficacy endpoints of Radiation Therapy Oncology Group protocol 0247, primary endpoint analysis of which demonstrated that preoperative radiation therapy (RT) with capecitabine plus oxaliplatin achieved a pathologic complete remission prespecified threshold (21%) to merit further study, whereas RT with capecitabine plus irinotecan did not (10%). Methods and Materials: A randomized, phase 2 trial evaluated preoperative RT (50.4 Gy in 1.8-Gy fractions) with 2 concurrent chemotherapy regimens: (1) capecitabine (1200 mg/m 2 /d Monday-Friday) plus irinotecan (50 mg/m 2 /wk × 4); and (2) capecitabine (1650 mg/m 2 /d Monday-Friday) plus oxaliplatin (50 mg/m 2 /wk × 5) for clinical T3 or T4 rectal cancer. Surgery was performed 4 to 8 weeks after chemoradiation, then 4 to 6 weeks later, adjuvant chemotherapy (oxaliplatin 85 mg/m 2 ; leucovorin 400 mg/m 2 ; 5-fluorouracil 400 mg/m 2 ; 5-fluorouracil 2400 mg/m 2 ) every 2 weeks × 9. Disease-free survival (DFS) and overall survival (OS) were estimated univariately by the Kaplan-Meier method. Local–regional failure (LRF), distant failure (DF), and second primary failure (SP) were estimated by the cumulative incidence method. No statistical comparisons were made between arms because each was evaluated individually. Results: A total of 104 patients (median age, 57 years) were treated; characteristics were similar for both arms. Median follow-up for RT with capecitabine/irinotecan arm was 3.77 years and for RT with capecitabine/oxaliplatin arm was 3.97 years. Four-year DFS, OS, LRF, DF, and SP estimates for capecitabine/irinotecan arm were 68%, 85%, 16%, 24%, and 2%, respectively. The 4-year DFS, OS, LRF, DF, and SP failure estimates for capecitabine/oxaliplatin arm were 62%, 75%, 18%, 30%, and 6%, respectively. Conclusions: Efficacy results for both arms are similar to other reported studies but suggest that pathologic complete remission is an unsuitable surrogate for

Efficacy Endpoints of Radiation Therapy Group Protocol 0247: A Randomized, Phase 2 Study of Neoadjuvant Radiation Therapy Plus Concurrent Capecitabine and Irinotecan or Capecitabine and Oxaliplatin for Patients With Locally Advanced Rectal Cancer

Energy Technology Data Exchange (ETDEWEB)

Wong, Stuart J. [Medical College of Wisconsin, Madison, Wisconsin (United States); Moughan, Jennifer [Radiation Therapy Oncology Group Statistical Center, Philadelphia, Pennsylvania (United States); Meropol, Neal J., E-mail: Neal.Meropol@case.edu [University Hospitals Seidman Cancer Center, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio (United States); Anne, Pramila Rani [Department of Radiation Oncology and Medical Oncology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Kachnic, Lisa A. [Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts (United States); Rashid, Asif [Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Watson, James C. [Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Mitchell, Edith P. [Department of Radiation Oncology and Medical Oncology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Pollock, Jondavid [The Schiffler Cancer Center, Wheeling, West Virginia (United States); Lee, R. Jeffrey [Intermountain Medical Center, Murray, Utah (United States); Haddock, Michael [Division of Radiation Oncology, Mayo Clinic, Rochester, Minnesota (United States); Erickson, Beth A. [Medical College of Wisconsin, Madison, Wisconsin (United States); Willett, Christopher G. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States)

2015-01-01

Purpose: To report secondary efficacy endpoints of Radiation Therapy Oncology Group protocol 0247, primary endpoint analysis of which demonstrated that preoperative radiation therapy (RT) with capecitabine plus oxaliplatin achieved a pathologic complete remission prespecified threshold (21%) to merit further study, whereas RT with capecitabine plus irinotecan did not (10%). Methods and Materials: A randomized, phase 2 trial evaluated preoperative RT (50.4 Gy in 1.8-Gy fractions) with 2 concurrent chemotherapy regimens: (1) capecitabine (1200 mg/m{sup 2}/d Monday-Friday) plus irinotecan (50 mg/m{sup 2}/wk × 4); and (2) capecitabine (1650 mg/m{sup 2}/d Monday-Friday) plus oxaliplatin (50 mg/m{sup 2}/wk × 5) for clinical T3 or T4 rectal cancer. Surgery was performed 4 to 8 weeks after chemoradiation, then 4 to 6 weeks later, adjuvant chemotherapy (oxaliplatin 85 mg/m{sup 2}; leucovorin 400 mg/m{sup 2}; 5-fluorouracil 400 mg/m{sup 2}; 5-fluorouracil 2400 mg/m{sup 2}) every 2 weeks × 9. Disease-free survival (DFS) and overall survival (OS) were estimated univariately by the Kaplan-Meier method. Local–regional failure (LRF), distant failure (DF), and second primary failure (SP) were estimated by the cumulative incidence method. No statistical comparisons were made between arms because each was evaluated individually. Results: A total of 104 patients (median age, 57 years) were treated; characteristics were similar for both arms. Median follow-up for RT with capecitabine/irinotecan arm was 3.77 years and for RT with capecitabine/oxaliplatin arm was 3.97 years. Four-year DFS, OS, LRF, DF, and SP estimates for capecitabine/irinotecan arm were 68%, 85%, 16%, 24%, and 2%, respectively. The 4-year DFS, OS, LRF, DF, and SP failure estimates for capecitabine/oxaliplatin arm were 62%, 75%, 18%, 30%, and 6%, respectively. Conclusions: Efficacy results for both arms are similar to other reported studies but suggest that pathologic complete remission is an

Efficacy of breast shielding during CT of the head

International Nuclear Information System (INIS)

Brnic, Z.; Hebrang, A.; Anic, P.

2002-01-01

The aims of this study were to investigate in vivo the levels of breast exposure to scatter radiation in head CT examination and the dependence of breast exposure upon body constitution. We tried to estimate the efficacy of external lead shielding as a mean of breast dose reduction. We wanted to estimate how much radiation reaches the organ from outside, in comparison to radiation load due to internal scatter

Enhancing the radiation response of tumors but not early or late responding normal tissues using a vascular disrupting agent

DEFF Research Database (Denmark)

Horsman, Michael R

2017-01-01

INTRODUCTION: Vascular disrupting agents (VDAs) damage tumor vasculature and enhance tumor radiation response. In this pre-clinical study, we combined radiation with the leading VDA in clinical development, combretastatin A-4 phosphate (CA4P), and compared the effects seen in tumors and relevant...... normal tissues. MATERIAL AND METHODS: Radiation was applied locally to tissues in CDF1 mice to produce full radiation dose-response curves. CA4P (250 mg/kg) was intraperitoneally (i.p.) injected within 30 minutes after irradiating. Response of 200 mm3 foot implanted C3H mammary carcinomas was assessed......% increase in ventilation rate measured by plethysmography within 9 months). A Chi-squared test was used for statistical comparisons (significance level of p 4P. The radiation...

Electron Paramagnetic Resonance pO2 Image Tumor Oxygen-Guided Radiation Therapy Optimization.

Science.gov (United States)

Epel, Boris; Maggio, Matt; Pelizzari, Charles; Halpern, Howard J

2017-01-01

Modern standards for radiation treatment do not take into account tumor oxygenation for radiation treatment planning. Strong correlation between tumor oxygenation and radiation treatment success suggests that oxygen-guided radiation therapy (OGRT) may be a promising enhancement of cancer radiation treatment. We have developed an OGRT protocol for rodents. Electron paramagnetic resonance (EPR) imaging is used for recording oxygen maps with high spatial resolution and excellent accuracy better than 1 torr. Radiation is delivered with an animal intensity modulated radiation therapy (IMRT) XRAD225Cx micro-CT/ therapy system. The radiation plan is delivered in two steps. First, a uniform 15% tumor control dose (TCD 15 ) is delivered to the whole tumor. In the second step, an additional booster dose amounting to the difference between TCD 98 and TCD 15 is delivered to radio-resistant, hypoxic tumor regions. Delivery of the booster dose is performed using a multiport conformal beam protocol. For radiation beam shaping we used individual radiation blocks 3D-printed from tungsten infused ABS polymer. Calculation of beam geometry and the production of blocks is performed next to the EPR imager, immediately after oxygen imaging. Preliminary results demonstrate the sub-millimeter precision of the radiation delivery and high dose accuracy. The efficacy of the radiation treatment is currently being tested on syngeneic FSa fibrosarcoma tumors grown in the legs of C3H mice.

Suppression of Remodeling Behaviors with Arachidonic Acid Modification for Enhanced in vivo Antiatherogenic Efficacies of Lovastatin-loaded Discoidal Recombinant High Density Lipoprotein.

Science.gov (United States)

He, Hongliang; Zhang, Mengyuan; Liu, Lisha; Zhang, Shuangshuang; Liu, Jianping; Zhang, Wenli

2015-10-01

A series of in vitro evaluation in our previous studies had proved that arachidonic acid (AA) modification could suppress the remodeling behaviors of lovastatin-loaded discoidal reconstituted high density lipoprotein (LT-d-rHDL) by restraining the reactivity with lecithin cholesterol acyltransferase (LCAT) for reducing undesired drug leakage. This study focuses on the investigation of AA-modified LT-d-rHDL (AA-LT-d-rHDL) in atherosclerotic New Zealand White (NZW) rabbit models to explore whether AA modification could enhance drug targeting delivery and improve antiatherogenic efficacies in vivo. After pharmacokinetics of AA-LT-d-rHDL modified with different AA amount were investigated in atherosclerotic NZW rabbits, atherosclerotic lesions targeting property was assessed by ex vivo imaging of aortic tree and drug distribution. Furthermore, their antiatherogenic efficacies were elaborately evaluated and compared by typical biochemical indices. With AA modification amount augmenting, circulation time of AA-LT-d-rHDL was prolonged, and drug accumulation in the target locus was increased, eventually the significant appreciation in antiatherogenic efficacies were further supported by lower level of bad cholesterol, decreased atherosclerotic lesions areas and mean intima-media thickness (MIT), markedly attenuated matrix metalloproteinase-9 (MMP-9) protein expression and macrophage infiltration. This proof-of-concept study demonstrated that AA-LT-d-rHDL could enhance drug accumulation in atherosclerotic lesion and impede atherosclerosis progression more effectively.

SiRNA-mediated IGF-1R inhibition sensitizes human colon cancer SW480 cells to radiation

International Nuclear Information System (INIS)

Yavari, Kamal; Taghikhani, Mohammad; Mesbah-Namin, Seyed A.; Maragheh, Mohammad Ghannadi; Babaei, Mohammad Hosein; Arfaee, Ali Jabbary; Madani, Hossein; Mirzaei, Hamid Reza

2010-01-01

Purpose. Insulin like growth factor receptor 1 (IGF-1R) is well-documented to play a key role in radiation response and tumor radiosensitivity, thus offering an attractive clinic drug target to enhance tumor sensitivity to anti-cancer radiotherapy. Material and methods. Human colon carcinoma SW480 cells were transfected with the specific small interference RNA (siRNA) expression vector (pkD-shRNA-IGF-1R-V2) designed to target IGF-1R mRNA. The expression of IGF-1R mRNA and its protein among the transfected and untransfected cells were detected by semi-quantitative RT-PCR and ELISA assay. The changes in cell radiosensitivity were examined by MTT assay. Results. Transfection of mammalian expression vector pkD containing IGF-1R siRNA was shown to reduce IGF-1R mRNA levels by up to 95%. ELISA assay detected a similar inhibition of IGF-1R protein levels in cells transfected with IGF-1R siRNA. SW480 cells transfected with the expression vector for siRNA significantly rendered cells more sensitive to radiation and the highest radiation enhancement ratio was 2.02 ± 0.08. Conclusion. These data provide the first evidence that specific siRNA fragment (pkD-shRNA-IGF-1R-V2) targeting human IGF-1R mRNA is able to enhance colon cancer radiosensitivity. Also results indicated that, combining IGF-1R siRNA and radiation significantly enhances antitumor efficacy compared with either modality alone

Radiative recombination of highly charged ions: Enhanced rates at low energies

International Nuclear Information System (INIS)

Frank, A.; Mueller, A.; Haselbauer, J.; Schennach, S.; Spies, W.; Uwira, O.; Wagner, M.

1992-01-01

In a single-pass merged-beams experiment employing a dense cold electron target recombination of highly charged ions is studied. Unexpected high recombination rates are observed at low energies E cm in the electron-ion center-of-mass frame. In particular, theoretical estimates for radiative recombination are dramatically exceeded by the experimental recombination rates at E cm =0 eV for U 28+ and for Au 25+ ions. Considerable rate enhancement is also observed for Ar 15+ . This points to a general phenomenon which has to be interpreted as a consequence of high electron densities, low electron beam temperatures, high ion charge states and presence of strong magnetic fields. (orig.)

The Combined Effects of Classroom Teaching and Learning Strategy Use on Students' Chemistry Self-Efficacy

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Cheung, Derek

2015-02-01

For students to be successful in school chemistry, a strong sense of self-efficacy is essential. Chemistry self-efficacy can be defined as students' beliefs about the extent to which they are capable of performing specific chemistry tasks. According to Bandura (Psychol. Rev. 84:191-215, 1977), students acquire information about their level of self-efficacy from four sources: performance accomplishments, vicarious experiences, verbal persuasion, and physiological states. No published studies have investigated how instructional strategies in chemistry lessons can provide students with positive experiences with these four sources of self-efficacy information and how the instructional strategies promote students' chemistry self-efficacy. In this study, questionnaire items were constructed to measure student perceptions about instructional strategies, termed efficacy-enhancing teaching, which can provide positive experiences with the four sources of self-efficacy information. Structural equation modeling was then applied to test a hypothesized mediation model, positing that efficacy-enhancing teaching positively affects students' chemistry self-efficacy through their use of deep learning strategies such as metacognitive control strategies. A total of 590 chemistry students at nine secondary schools in Hong Kong participated in the survey. The mediation model provided a good fit to the student data. Efficacy-enhancing teaching had a direct effect on students' chemistry self-efficacy. Efficacy-enhancing teaching also directly affected students' use of deep learning strategies, which in turn affected students' chemistry self-efficacy. The implications of these findings for developing secondary school students' chemistry self-efficacy are discussed.

Enhancing Self-Efficacy in Elementary Science Teaching With Professional Learning Communities

Science.gov (United States)

Mintzes, Joel J.; Marcum, Bev; Messerschmidt-Yates, Christl; Mark, Andrew

2013-11-01

Emerging from Bandura's Social Learning Theory, this study of in-service elementary school teachers examined the effects of sustained Professional Learning Communities (PLCs) on self-efficacy in science teaching. Based on mixed research methods, and a non-equivalent control group experimental design, the investigation explored changes in personal self-efficacy and outcome expectancy among teachers engaged in PLCs that featured Demonstration Laboratories, Lesson Study, and annual Summer Institutes. Significant changes favoring the experimental group were found on all quantitative measures of self-efficacy. Structured clinical interviews revealed that observed changes were largely attributable to a wide range of direct (mastery) and vicarious experiences, as well as emotional reinforcement and social persuasion.

Carboplatin enhances the production and persistence of radiation-induced DNA single-strand breaks

International Nuclear Information System (INIS)

Yang, L.; Douple, E.B.; O'Hara, J.A.; Wang, H.J.

1995-01-01

Fluorometric analysis of DNA unwinding and alkaline elution were used to investigate the production and persistence of DNA single-strand breaks (SSBs) in Chinese hamster V79 and xrs-5 cells treated with the chemotherapeutic agent carboplatin in combination with radiation. Carboplatin was administered to cells before irradiation in hypoxic conditions, or the drug was added immediately after irradiation during the postirradiation recovery period in air. The results of DNA unwinding studies suggest that carboplatin enhances the production of radiation-induced SSBs in hypoxic V79 cells and xrs-5 cells by a factor of 1.86 and 1.83, respectively, when combined with radiation compared to the SSBs produced by irradiation alone. Carboplatin alone did not produce a measureable number of SSBs. Alkaline elution profiles also indicated that the rate of elution of SSBs was higher in cells treated with the carboplatin is present after irradiation and during the postirradiation recovery period, the rejoining of radiation-induced SSBs by a factor of 1.46 in V79 cells with 20 Gy irradiation and by a factor of 2.02 in xrs-5 cells with 20 Gy irradiation. When carboplatin is present after irradiation and during the postirradiation recovery period, the rejoining of radiation-induced SSBs is inhibited during this postirradiation incubation period (radiopotentiation) with a relative inhibition factor at 1 h postirradiation of 1.25 in V79 cells and 1.15 in xrs-5 cells. An increased production and persistence of SSBs resulting from the interaction of carboplatin with radiation may be an important step in the mechanism responsible for the potentiated cell killing previously from studies in animal tumors and in cultured cells. 31 refs., 7 figs

Fractionated radiation therapy in the treatment of intracranial meningiomas: local control, functional efficacy, and tolerance in 91 patients

International Nuclear Information System (INIS)

Maire, Jean-Philippe; Caudry, Michel; Guerin, Jean; Celerier, Denis; San Galli, Francois; Causse, Nicole; Trouette, Renaud; Dautheribes, Michel

1995-01-01

Purpose: To evaluate efficacy and tolerance of external fractionated radiation therapy (RT) in the treatment of intracranial meningiomas. Methods and Materials: From January 1981 to September 1993, 91 patients with intracranial meningiomas were treated with fractionated RT. Indications were as follows: (a) incomplete surgical resection, 29 patients; (b) tumor recurrences without considering the amount of the second resection, if performed, 14 patients; (c) completely excised angioblastic, aggressive benign, and anaplastic tumors, 8 patients; (d) medically inoperable and basilar tumors where operation would involve considerable danger or permanent neurological damage, 44 patients. Most patients were irradiated with 6 to 9 MV photon beams. A three- to four-field technique with coned-down portals was used. Doses were calculated on the 95% isodose and were given 5 days a week for a median total dose of 52 Gy (1.80 Gy/fraction). Results: Median follow-up from radiation therapy was 40 months. Acute tolerance was excellent, but there were six late delayed injuries. Tumor recurrences occurred in six cases. Six patients died from their tumor or RT complications, 19 from nontumoral reasons. Three, 5- and 10-year survival rates were 82, 71, and 40%, respectively. The most significant prognostic factor was age: 5-year survival rate was 86% for patients less than 65 years and 37% for patients more than 65. However, there were no differences in recurrence-free survival rates between patients younger than 65 and the oldest ones. Of 60 symptomatic patients with neurological deficits, 43 had neurological improvement (72%), beginning in some cases within 15 to 20 days after starting RT. Conclusion: These results reassess the role of fractionated RT in the treatment of meningiomas, and stress on its efficacy, especially on cranial nerves palsies, without severe toxicity in most cases

The Relationship between Sources of Self-Efficacy in Classroom Environments and the Strength of Computer Self-Efficacy Beliefs

Science.gov (United States)

Srisupawong, Yuwarat; Koul, Ravinder; Neanchaleay, Jariya; Murphy, Elizabeth; Francois, Emmanuel Jean

2018-01-01

Motivation and success in computer-science courses are influenced by the strength of students' self-efficacy (SE) beliefs in their learning abilities. Students with weak SE may struggle to be successful in a computer-science course. This study investigated the factors that enhance or impede the computer self-efficacy (CSE) of computer-science…

AMRI-59 has a role of radiosensitizer via enhancement of γ-ionizing radiation-induced apoptotic cell death

Energy Technology Data Exchange (ETDEWEB)

Hong, Wan Gi; Cho, Jeong Hyun; Kim, Ju Yeon; Hwang, Sang Gu; Um, Hong Duck; Park, Jong Kuk [KAERI, Daejeon (Korea, Republic of)

2016-05-15

Recent in vitro studies have suggested that may increase the invasiveness of some cancer cells (e.g., glioma, hepatocellular carcinoma, and pancreatic cancer cells) by stimulating several intracellular signaling pathways and in vivo studies have found that radiotherapy of primary tumor sites may promote metastasis. Thus, in addition to having therapeutic effects, IR might promote the malignant traits of surviving cancer cells. The existing efforts to develop radiosensitizing agents have focused on overcoming radioresistance and reducing damage to normal tissues. Recently, concepts of personalized- or precision medicine are developed due to advancement of mega data technique, which provide new targets to develop new anti-cancer drugs. In this study, we sought to identify the radiosensitizer effect of AMRI-59 in vitro and in vivo., which is recently developed specific inhibitor of peroxiredoxin (Prx) I. AMRI-59 enhanced radiation-induced cell death and its mean calculated dose enhancement ratio was 1.26. We also found combination of AMRI-59 and IR In a xenograft assay, the combined PHCM and radiation group showed 14.3 days of growth delay versus the control in terms of tumor growth. The enhancement factor of this combined treatment was determined to be 2.03.

In vitro study of combined cilengitide and radiation treatment in breast cancer cell lines

International Nuclear Information System (INIS)

Lautenschlaeger, Tim; Perry, James; Peereboom, David; Li, Bin; Ibrahim, Ahmed; Huebner, Alexander; Meng, Wei; White, Julia; Chakravarti, Arnab

2013-01-01

Brain metastasis from breast cancer poses a major clinical challenge. Integrins play a role in regulating adhesion, growth, motility, and survival, and have been shown to be critical for metastatic growth in the brain in preclinical models. Cilengitide, an αvβ3/αvβ5 integrin inhibitor, has previously been studied as an anti-cancer drug in various tumor types. Previous studies have shown additive effects of cilengitide and radiation in lung cancer and glioblastoma cell lines. The ability of cilengitide to enhance the effects of radiation was examined preclinically in the setting of breast cancer to assess its possible efficacy in the setting of brain metastasis from breast cancer. Our panel of breast cells was composed of four cell lines: T-47D (ER/PR+, Her2-, luminal A), MCF-7 (ER/PR+, Her2-, luminal A), MDA-MB-231 (TNBC, basal B), MDA-MB-468 (TNBC, basal A). The presence of cilengitide targets, β3 and β5 integrin, was first determined. Cell detachment was determined by cell counting, cell proliferation was determined by MTS proliferation assay, and apoptosis was measured by Annexin V staining and flow cytometry. The efficacy of cilengitide treatment alone was analyzed, followed by assessment of combined cilengitide and radiation treatment. Integrin β3 knockdown was performed, followed by cilengitide and radiation treatment to test for incomplete target inhibition by cilengitide, in high β3 expressing cells. We observed that all cell lines examined expressed both β3 and β5 integrin and that cilengitide was able to induce cell detachment and reduced proliferation in our panel. Annexin V assays revealed that a portion of these effects was due to cilengitide-induced apoptosis. Combined treatment with cilengitide and radiation served to further reduce proliferation compared to either treatment alone. Following β3 integrin knockdown, radiosensitization in combination with cilengitide was observed in a previously non-responsive cell line (MDA-MB-231

WE-FG-BRA-07: Theranostic Nanoparticles Improve Clinical MR-Guided Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Detappe, A [Dana-Farber Cancer Institute, Boston, MA (United States); Institut Lumiere-Matiere, Lyon, FR (France); Kunjachan, S; Berbeco, R [Dana-Farber Cancer Institute, Boston, MA (United States); Sancey, L; Motto-Ros, V; Tillement, O [Institut Lumiere-Matiere, Lyon, FR (France)

2016-06-15

Purpose: MR-guided radiation therapy is a current and emerging clinical reality. We have designed and tested a silica-based gadolinium chelates nanoparticle (AGuIX) for integration with MR-guided radiation therapy. The AGuIX nanoparticles used in this study are a dual-modality probe with radiosensitization properties and better MRI contrast than current FDA-approved gadolinium chelates. In advance of an approved Phase I clinical trial, we report on the efficacy and safety in multiple animal models and clinically relevant radiation conditions. By modeling our study on current clinic workflows, we show compatibility with modern patient care, thus heightening the translational significance of this research. Methods: The dual imaging and therapy functionality of AGuIX was investigated in mice with clinical radiation beams while safety was evaluated in mice, and nonhuman primates after systemic injection of 0.25 mg/g of nanoparticles. MRI/ICP-MS were used to measure tumor uptake and biodistribution. Due to their small size (2–3 nm), AGuIX have good renal clearance (t1/2=19min). We performed in vitro cell uptake quantification and radiosensitization studies (clonogenic assays and DNA damage quantification). In vivo radiation therapy studies were performed with both 6MV and 6MV-FFF clinical radiation beams. Histology was performed to measure the increase in DNA damage in the tumor and to evaluate the toxicity in healthy tissues. Results: In vitro and in vivo results demonstrate statistically significant increase (P < 0.01) in DNA damage, tumor growth supression and survival (+100 days) compared to radiation alone. Negligible toxicity was observed in all of the animal models. The combination of 6MV-FFF/AGuIX demonstrated a substantial dose enhancement compared to 6MV/AGuIX (DEF = 1.36 vs. 1.22) due to the higher proportion of low energy photons. Conclusion: With demonstrated efficacy and negligible toxicity in mice and non-human primates, AGuIX is a biocompatible

WE-FG-BRA-07: Theranostic Nanoparticles Improve Clinical MR-Guided Radiation Therapy

International Nuclear Information System (INIS)

Detappe, A; Kunjachan, S; Berbeco, R; Sancey, L; Motto-Ros, V; Tillement, O

2016-01-01

Purpose: MR-guided radiation therapy is a current and emerging clinical reality. We have designed and tested a silica-based gadolinium chelates nanoparticle (AGuIX) for integration with MR-guided radiation therapy. The AGuIX nanoparticles used in this study are a dual-modality probe with radiosensitization properties and better MRI contrast than current FDA-approved gadolinium chelates. In advance of an approved Phase I clinical trial, we report on the efficacy and safety in multiple animal models and clinically relevant radiation conditions. By modeling our study on current clinic workflows, we show compatibility with modern patient care, thus heightening the translational significance of this research. Methods: The dual imaging and therapy functionality of AGuIX was investigated in mice with clinical radiation beams while safety was evaluated in mice, and nonhuman primates after systemic injection of 0.25 mg/g of nanoparticles. MRI/ICP-MS were used to measure tumor uptake and biodistribution. Due to their small size (2–3 nm), AGuIX have good renal clearance (t1/2=19min). We performed in vitro cell uptake quantification and radiosensitization studies (clonogenic assays and DNA damage quantification). In vivo radiation therapy studies were performed with both 6MV and 6MV-FFF clinical radiation beams. Histology was performed to measure the increase in DNA damage in the tumor and to evaluate the toxicity in healthy tissues. Results: In vitro and in vivo results demonstrate statistically significant increase (P < 0.01) in DNA damage, tumor growth supression and survival (+100 days) compared to radiation alone. Negligible toxicity was observed in all of the animal models. The combination of 6MV-FFF/AGuIX demonstrated a substantial dose enhancement compared to 6MV/AGuIX (DEF = 1.36 vs. 1.22) due to the higher proportion of low energy photons. Conclusion: With demonstrated efficacy and negligible toxicity in mice and non-human primates, AGuIX is a biocompatible

Roadmap to Clinical Use of Gold Nanoparticles for Radiation Sensitization

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Schuemann, Jan, E-mail: jschuemann@mgh.harvard.edu [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Berbeco, Ross [Department of Radiation Oncology, Brigham and Women' s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts (United States); Chithrani, Devika B. [Department of Physics, Ryerson University, Toronto, Ontario (Canada); Cho, Sang Hyun [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kumar, Rajiv [Nanomedicine Science and Technology Center, Northeastern University, Boston, Massachusetts (United States); Department of Radiation Oncology, Harvard Medical School, Boston, Massachusetts (United States); McMahon, Stephen J. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Centre for Cancer Research and Cell Biology, Queen' s University Belfast, Belfast, Northern Ireland (United Kingdom); Sridhar, Srinivas [Nanomedicine Science and Technology Center, Northeastern University, Boston, Massachusetts (United States); Department of Radiation Oncology, Harvard Medical School, Boston, Massachusetts (United States); Krishnan, Sunil [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

2016-01-01

The past decade has seen a dramatic increase in interest in the use of gold nanoparticles (GNPs) as radiation sensitizers for radiation therapy. This interest was initially driven by their strong absorption of ionizing radiation and the resulting ability to increase dose deposited within target volumes even at relatively low concentrations. These early observations are supported by extensive experimental validation, showing GNPs' efficacy at sensitizing tumors in both in vitro and in vivo systems to a range of types of ionizing radiation, including kilovoltage and megavoltage X rays as well as charged particles. Despite this experimental validation, there has been limited translation of GNP-mediated radiation sensitization to a clinical setting. One of the key challenges in this area is the wide range of experimental systems that have been investigated, spanning a range of particle sizes, shapes, and preparations. As a result, mechanisms of uptake and radiation sensitization have remained difficult to clearly identify. This has proven a significant impediment to the identification of optimal GNP formulations which strike a balance among their radiation sensitizing properties, their specificity to the tumors, their biocompatibility, and their imageability in vivo. This white paper reviews the current state of knowledge in each of the areas concerning the use of GNPs as radiosensitizers, and outlines the steps which will be required to advance GNP-enhanced radiation therapy from their current pre-clinical setting to clinical trials and eventual routine usage.

How Setting Goals Enhances Learners’ Self-Efficacy Beliefs in Listening Comprehension

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Liliana Ballesteros Muñoz

2014-04-01

Full Text Available This article outlines a study that explores the relationship between SMART goal setting (Specific, Measurable, Attainable, Relevant, and Time-based and learning English in Colombia concerning a foreign language learners’ self-efficacy beliefs in listening. The participants were seventh and ninth grade students of two schools in Bogotá, Colombia. The results revealed that self-efficacy was highly positive when related to goal setting as students were able to set SMART goals to improve their listening comprehension and learners showed improvement in self-efficacy beliefs and felt more motivated while completing listening tasks related to songs. Furthermore this study shows that goal setting training can be incorporated successfully into the English as a foreign language classroom.

Short Communication: Improved Stability and Efficacy of Diclofenac ...

African Journals Online (AJOL)

An oleogel-based formulation of diclofenac diethylamine (DFDA) was prepared and evaluated for enhanced stability and efficacy. Efficacy was evaluated by carrageenan-induced paw oedema method on albino rats and compared with marketed emulgels. The present findings revealed that the developed oleogel ...

An integrated circuit/microsystem/nano-enhanced four species radiation sensor for inexpensive fissionable material detection

Science.gov (United States)

Waguespack, Randy Paul

2011-12-01

Small scale radiation detectors sensitive to alpha, beta, electromagnetic, neutron radiation are needed to combat the threat of nuclear terrorism and maintain national security. There are many types of radiation detectors on the market, and the type of detector chosen is usually determined by the type of particle to be detected. In the case of fissionable material, an ideal detector needs to detect all four types of radiation, which is not the focus of many detectors. For fissionable materials, the two main types of radiation that must be detected are gamma rays and neutrons. Our detector uses a glass or quartz scintillator doped with 10B nanoparticles to detect all four types of radiation particles. Boron-10 has a thermal neutron cross section of 3,840 barns. The interaction between the neutron and boron results in a secondary charge particle in the form of an alpha particle to be emitted, which is detectable by the scintillator. Radiation impinging on the scintillator matrix produces varying optical pulses dependent on the energy of the particles. The optical pulses are then detected by a photomultiplier (PM) tube, creating a current proportional to the energy of the particle. Current pulses from the PM tube are differentiated by on-chip pulse height spectroscopy, allowing for source discrimination. The pulse height circuitry has been fabricated with discrete circuits and designed into an integrated circuit package. The ability to replace traditional PM tubes with a smaller, less expensive photomultiplier will further reduce the size of the device and enhance the cost effectiveness and portability of the detector.

Study of arsenic trioxide-induced vascular shutdown and enhancement with radiation in solid tumor

International Nuclear Information System (INIS)

Monzen, Hajime; Griffin, R.J.; Williams, B.W.; Amamo, Morikazu; Ando, Satoshi; Hasegawa, Takeo

2004-01-01

Arsenic trioxide (ATO) has been reported to be an effective chemotherapeutic agent for acute promyelocytic leukemia (APL), and, recently, anti-tumor effect has been demonstrated in solid tumors. However, little is known about the mechanism of action of the ATO effect on solid tumor. We investigated the anti-vascular effect of ATO and the potential of combining ATO with radiation therapy. We studied the anti-vascular effect of ATO and radiosensitization of squamous cell carcinoma (SCC) VII murine tumors of C3H mice. The anti-vascular effect was examined using magnetic resonance imaging (MRI), and radiosensitivity was studied by clonogenic assay and tumor growth delay. Histopathological changes of the tumors after various treatments were also observed with hematoxylin and eosin (H and E) staining. Necrosis and blood flow changes in the central region of tumors in the hind limbs of the animals were observed on T2-weighted imaging after an intraperitoneal (i.p.) injection of 8 mg/kg of ATO alone. ATO exposure followed by radiation decreased the clonogenic survival of SCC VII cells compared with either treatment alone. Tumor growth delay after 10-20 Gy of radiation alone was increased slightly compared with control tumors, but the combination of ATO injection 2 hours before exposure to 20 Gy of radiation significantly prolonged tumor growth delay by almost 20 days. The results suggest that ATO and radiation can enhance the radiosensitivity of solid tumor. (author)

Teachers’ work ability: a study of relationships between collective efficacy and self-efficacy beliefs

Directory of Open Access Journals (Sweden)

Guidetti G

2018-05-01

Full Text Available Gloria Guidetti,1 Sara Viotti,1 Andreina Bruno,2 Daniela Converso1 1Department of Psychology, University of Turin, Turin, Italy; 2Department of Education Science, University of Genoa, Genoa, Italy Introduction: Work ability constitutes one of the most studied well-being indicators related to work. Past research highlighted the relationship with work-related resources and demands, and personal resources. However, no studies highlight the role of collective and self-efficacy beliefs in sustaining work ability. Purpose: The purpose of this study was to examine whether and by which mechanism work ability is linked with individual and collective efficacies in a sample of primary and middle school teachers. Materials and methods: Using a dataset consisting of 415 primary and middle school Italian teachers, the analysis tested for the mediating role of self-efficacy between collective efficacy and work ability. Results: Mediational analysis highlights that teachers’ self-efficacy totally mediates the relationship between collective efficacy and perceived work ability. Conclusion: Results of this study enhance the theoretical knowledge and empirical evidence regarding the link between teachers’ collective efficacy and self-efficacy, giving further emphasis to the concept of collective efficacy in school contexts. Moreover, the results contribute to the study of well-being in the teaching profession, highlighting a process that sustains and promotes levels of work ability through both collective and personal resources. Keywords: collective efficacy, mediation, self-efficacy, teachers, work ability

Some Contributions of Self-Efficacy Research to Self-Concept Theory.

Science.gov (United States)

Gorrell, Jeffrey

1990-01-01

Self-efficacy theory and research contribute to self-concept theory primarily by supporting the enhancement model of belief change. This article describes current problems with self-concept theory, describes self-efficacy research, and suggests that self-efficacy theory and methodology present findings that strengthen the association between…

An iterative method applied to optimize the design of PIN photodiodes for enhanced radiation tolerance and maximum light response

International Nuclear Information System (INIS)

Cedola, A.P.; Cappelletti, M.A.; Casas, G.; Peltzer y Blanca, E.L.

2011-01-01

An iterative method based on numerical simulations was developed to enhance the proton radiation tolerance and the responsivity of Si PIN photodiodes. The method allows to calculate the optimal values of the intrinsic layer thickness and the incident light wavelength, in function of the light intensity and the maximum proton fluence to be supported by the device. These results minimize the effects of radiation on the total reverse current of the photodiode and maximize its response to light. The implementation of the method is useful in the design of devices whose operation point should not suffer variations due to radiation.

Application of low dose radiation and low concentration contrast media in enhanced CT scans in children with congenital heart disease.

Science.gov (United States)

Liu, Zhimin; Song, Lei; Yu, Tong; Gao, Jun; Zhang, Qifeng; Jiang, Ling; Liu, Yong; Peng, Yun

2016-09-01

The aim of this study was to explore the feasibility of using low dose radiation and low concentration contrast media in enhanced CT examinations in children with congenital heart disease. Ninety patients with congenital heart disease were randomly divided into three groups of 30 patients each who underwent contrast-enhanced cardiac scans on a Discovery CT750 HD scanner. Group A received 270 mg I/mL iodixanol, and group B received 320 mg I/mL iodixanol contrast media and was scanned with prospective ECG triggering mode. Group C received 320 mg I/mL iodixanol and was scanned with conventional retrospective ECG gating mode. The same weight-based contrast injection protocol was used for all three groups. Images were reconstructed using a 30% adaptive statistical iterative reconstruction (ASIR) algorithm and a 50% ASIR in groups A and B and a 30% ASIR in group C. The subjective and objective image quality evaluations, diagnostic accuracies, radiation doses and amounts of contrast media in the three groups were measured and compared. All images in the three groups met the diagnostic requirements, with the same diagnostic accuracy and image quality scores greater than 3 in a 4-point scoring system. However, ventricular enhancement and the objective noise, signal-to-noise ratio, contrast-to-noise ratio and subjective image quality scores in group C were better than those in groups A and B (all Pcontrast dose (14% lower than that of groups B and C). Enhanced CT scan images with low dose radiation and low concentration contrast media can meet the diagnostic requirements for examining children with congenital heart disease while reducing the potential risk of radiation damage and contrast-induced nephropathy. © 2016 John Wiley & Sons Ltd.

A Randomized Trial of Comparing the Efficacy of Two Neurofeedback Protocols for Treatment of Clinical and Cognitive Symptoms of ADHD: Theta Suppression/Beta Enhancement and Theta Suppression/Alpha Enhancement

Directory of Open Access Journals (Sweden)

Arash Mohagheghi

2017-01-01

Full Text Available Introduction. Neurofeedback (NF is an adjuvant or alternative therapy for children with Attention Deficit Hyperactivity Disorder (ADHD. This study intended to compare the efficacy of two different NF protocols on clinical and cognitive symptoms of ADHD. Materials and Methods. In this clinical trial, sixty children with ADHD aged 7 to 10 years old were randomly grouped to receive two different NF treatments (theta suppression/beta enhancement protocol and theta suppression/alpha enhancement protocol. Clinical and cognitive assessments were conducted prior to and following the treatment and also after an eight-week follow-up. Results. Both protocols alleviated the symptoms of ADHD in general (p<0.001, hyperactivity (p<0.001, inattention (p<0.001, and omission errors (p<0.001; however, they did not affect the oppositional and impulsive scales nor commission errors. These effects were maintained after an eight-week intervention-free period. The only significant difference between the two NF protocols was that high-frequency alpha enhancement protocol performed better in suppressing omission errors (p<0.001. Conclusion. The two NF protocols with theta suppression/beta enhancement and theta suppression/alpha enhancement have considerable and comparable effect on clinical symptoms of ADHD. Alpha enhancement protocol was more effective in suppressing omission errors.

Decreasing the apoptotic threshold with chelerythrine chloride enhances radiation cures in vivo

International Nuclear Information System (INIS)

Chmura, Steven J.; Mauceri, Helena; Quintans, Jose; Kufe, Donald W.; Weichselbaum, Ralph R.

1997-01-01

Purpose: The induction of apoptosis following ionizing radiation (IR) is proposed to enhance tumor curability. No study to date, however, has demonstrated that increased tumor cell apoptosis overcomes radioresistance. We tested this hypothesis in a xenograft of a radioresistant (D 0 =2.3 Gy) human carcinoma line (SQ20-B) which lacks function p53 and fails to undergo apoptosis following single doses of IR as high as 20 Gy in vitro. We employed chelerythrine chloride, a selective PKC inhibitor of group A and B isoforms, which induces apoptosis from the hydrolysis of sphingomyelin. Materials and Methods: SQ20-B xenographts were grown to 300-900mm 3 in athymic mice. Tumors were injected four times with 1 mg/kg of body weight chelerythrine chloride (LD 50 = 20mg/kg) on days 0, 4, 7, and 10. Radiation was fractionated 5Gy/day, 4 days per week, for a total of 50 Gy. Apoptotic cells were scored from H and E tumor sections by an observer blinded to the treatment condition. In vitro determination of apoptosis was based on flowcytometric (FACS) analysis of propidium iodide uptake, cell size changes, and nuclear morphology. Results: Treatment of SQ20-B cells with 2.5μM chelerythrine chloride prior to irradiation in-vitro with 4 Gy resulted in over 80% of the cells undergoing apoptosis within 36 hours compared to <3% with IR alone. Activation of neutral and acidic sphingomyelinase activity preceded the induction apoptosis by chelerythrine and IR. Pharmacological inhibitors of the caspases (Ced3/CPP32 related proteases) prevented apoptosis by chelerythrine or the combination of chelerythrine and IR. Chelerythrine chloride enhanced the killing effects in animals of ionizing radiation in a xenograft SQ20-B tumor model through increased tumor cell apoptosis (p<.0001). Tumor cures were increased in the combined chelerythrine and IR treatment (44%) compared to either IR (5%) or chelerythrine (15%) alone (p<.001). Normal tissue architecture and limb function were preserved

Plasmon-enhanced energy transfer for improved upconversion of infrared radiation in doped-lanthanide nanocrystals

Science.gov (United States)

Sun, Qi; Mundoor, Haridas; Ribot, Josep; Singh, Vivek; Smalyukh, Ivan; Nagpal, Prashant

2014-03-01

Upconversion of infrared radiation into visible light has been investigated for applications in biological imaging and photovoltaics. However, low conversion efficiency due to small absorption cross-section for infrared light (Yb3+) , and slow rate of energy transfer (to Er3+ states) has prevented application of upconversion photoluminescence (UPL) for diffuse sunlight or imaging tissue samples. Here, we utilize resonant surface plasmon polaritons (SPP) waves to enhance UPL in doped-lanthanide nanocrystals. Our analysis indicates that SPP waves not only enhance the electromagnetic field, and hence weak Purcell effect, but also increases the rate of resonant energy transfer from Yb3+ to Er3+ ions by 6 fold. While we do observe strong metal mediated quenching (14 fold) of green fluorescence on flat metal surfaces, the nanostructured metal is resonant in the infrared, and hence enhances the nanocrystal UPL. This strong columbic effect on energy transfer can have important implications for other fluorescent and excitonic systems too.

Plasmon-enhanced energy transfer for improved upconversion of infrared radiation in doped-lanthanide nanocrystals.

Science.gov (United States)

Sun, Qi-C; Mundoor, Haridas; Ribot, Josep C; Singh, Vivek; Smalyukh, Ivan I; Nagpal, Prashant

2014-01-08

Upconversion of infrared radiation into visible light has been investigated for applications in photovoltaics and biological imaging. However, low conversion efficiency due to small absorption cross-section for infrared light (Yb(3+)), and slow rate of energy transfer (to Er(3+) states) has prevented application of upconversion photoluminescence (UPL) for diffuse sunlight or imaging tissue samples. Here, we utilize resonant surface plasmon polaritons (SPP) waves to enhance UPL in doped-lanthanide nanocrystals. Our analysis indicates that SPP waves not only enhance the electromagnetic field, and hence weak Purcell effect, but also increase the rate of resonant energy transfer from Yb(3+) to Er(3+) ions by 6 fold. While we do observe strong metal mediated quenching (14-fold) of green fluorescence on flat metal surfaces, the nanostructured metal is resonant in the infrared and hence enhances the nanocrystal UPL. This strong Coulombic effect on energy transfer can have important implications for other fluorescent and excitonic systems too.

Enhancing the healing processes of chemical burns with He-Ne radiation

International Nuclear Information System (INIS)

Kakai, S.F.K.; Albarwari, S.E.; Alsenawi, T.A.

1988-02-01

The process by which He-Ne laser radiation (λ = 632.8 nm) enhances the healing of cutaneous wounds, made by concentrated nitric acid on mice has been studied. The dose used was of the order of 2.7 Joule per day, till the day of complete wound closure. The wounds were irradiated at three points on its periphery so that to form a semitriangular pattern this method was adopted, because chemical burns involve the killing of both the epidermis and dermis. The influence of the laser on the healing was estimated quantitatively and statistically, with a significance of p<0.001 over the control (the unirradiated). (author). 8 refs, 2 figs, 2 tabs

Novel Curcumin Diclofenac Conjugate Enhanced Curcumin Bioavailability and Efficacy in Streptococcal Cell Wall-induced Arthritis.

Science.gov (United States)

Jain, S K; Gill, M S; Pawar, H S; Suresh, Sarasija

2014-09-01

Curcumin-diclofenac conjugate as been synthesized by esterification of phenolic group of curcumin with the acid moiety of diclofenac, and characterized by mass spectrometry, NMR, FTIR, DSC, thermogravimetric analysis and X-ray diffraction analysis. The relative solubility of curcumin-diclofenac conjugate, curcumin and diclofenac; stability of curcumin-diclofenac conjugate in intestinal extract; permeability study of curcumin-diclofenac conjugate using the everted rat intestinal sac method; stability of curcumin-diclofenac conjugate in gastrointestinal fluids and in vitro efficacy have been evaluated. In vivo bioavailability of curcumin-diclofenac conjugate and curcumin in Sprague-Dawley rats, and antiarthritic activity of curcumin-diclofenac conjugate, curcumin and diclofenac in modified streptococcal cell wall-induced arthritis model in Balb/c mice to mimic rheumatoid arthritis in humans have also been studied. In all of the above studies, curcumin-diclofenac conjugate exhibited enhanced stability as compared to curcumin; its activity was twice that of diclofenac in inhibiting thermal protein denaturation taken as a measure of in vitro antiinflammatory activity; it enhanced the bioavailability of curcumin by more than five folds, and significantly (Parthritis in streptococcal cell wall-induced arthritis model as compared to both diclofenac and curcumin.

Local vibration enhanced the efficacy of passive exercise on mitigating bone loss in hindlimb unloading rats

Science.gov (United States)

Huang, Yunfei; Luan, Huiqin; Sun, Lianwen; Bi, Jingfang; Wang, Ying; Fan, Yubo

2017-08-01

Spaceflight induced bone loss is seriously affecting astronauts. Mechanical stimulation from exercise has been shown to restrain bone resorption as well as improve bone formation. Current exercise countermeasures in space cannot prevent it completely. Active exercise may convert to passive exercise in some ways because of the loss of gravity stimulus and inertia of exercise equipment. The aim of this study was to compare the efficacy of passive exercise or/and local vibration on counteracting the deterioration of the musculoskeletal system, including bone, muscle and tendons in tail-suspended rats. We hypothesized that local vibration could enhance the efficacy of passive exercise on countering bone loss. 40 Sprague Dawley rats were randomly distributed into five groups (n = 8, each): tail-suspension (TS), TS+35 Hz vibration (TSV), TS + passive exercise (TSP), TS + passive exercise coupled with 35 Hz vibration (TSPV) and control (CON). Passive exercise or/and local vibration was performed for 21 days. On day 0 and 21, bone mineral density (BMD) was observed by dual energy X-ray absorptiometry (DXA), and trabecular microstructure was evaluated by microcomputer tomography (μCT) analysis in vivo. Mechanical properties of tibia and tendon were determined by a mechanical testing system. Soleus and bone ash weight was tested by an electronic balance. Results showed that the passive exercise could not prevent the decrease of trabecular BMD, microstructure and bone ash weight induced by TS, whereas vibration and passive exercise coupled with local vibration (PV) could. Biomechanical properties of the tibia and tendon in TSPV group significantly increased compared with TS group. In summary, PV in this study was the best method in preventing weightlessness-induced bone loss. Consistent with our hypothesis, local vibration partly enhanced the effect of passive exercise. Furthermore, this study will be useful in improving countermeasure for astronauts, but also for the

Antimicrobial efficacy of oral topical agents on microorganisms associated with radiated head and neck cancer patients: an in vitro study.

Science.gov (United States)

Bidra, Avinash S; Tarrand, Jeffery J; Roberts, Dianna B; Rolston, Kenneth V; Chambers, Mark S

2011-04-01

A variety of oral topical agents have been used for prevention and management of radiotherapy-induced adverse effects. The antimicrobial nature of some of the commonly used agents is unknown. The purpose of this study was to evaluate antimicrobial efficacies of various oral topical agents on common microorganisms associated with radiated head and neck cancer patients. Seven commonly used topical oral agents-0.12% chlorhexidine with alcohol, 0.12% chlorhexidine without alcohol, baking soda-salt rinse, 0.4% stannous fluoride gel, 0.63% stannous fluoride rinse, calcium phosphate mouthrinse, and acemannan hydrogel (aloe vera) rinse-were evaluated in vitro for their antimicrobial efficacies against four common microorganisms. A combination of baking soda-salt rinse and 0.4% stannous fluoride gel was evaluated as the eighth agent. The microorganisms used were Staphylococcus aureus, group B Streptococcus, Escherichia coli, and Candida albicans. An ELISA reader was used to measure the turbidity of microbial culture wells and optical density (OD) values for each of the 960 wells recorded. Mean OD values were rank ordered based on their turbidity. One-way ANOVA with Tukey HSD post hoc analysis was used to study differences in OD values (P baking soda- salt, calcium phosphate rinse, and the combination of baking soda-salt and stannous fluoride gel. Mean OD values classified for microorganisms from lowest to highest were Escherichia coli, Staphylococcus aureus, group B Streptococcus, and Candida albicans. A significant difference among the antimicrobial efficacies of topical agents was evident for each of four microorganisms (P < .05). There was also a significant difference among the antimicrobial efficacies of the same topical agent on the four microorganisms tested (P < .05).

Reduction of arsenite-enhanced ultraviolet radiation-induced DNA damage by supplemental zinc

Energy Technology Data Exchange (ETDEWEB)

Cooper, Karen L.; King, Brenee S.; Sandoval, Monica M.; Liu, Ke Jian; Hudson, Laurie G., E-mail: lhudson@salud.unm.edu

2013-06-01

Arsenic is a recognized human carcinogen and there is evidence that arsenic augments the carcinogenicity of DNA damaging agents such as ultraviolet radiation (UVR) thereby acting as a co-carcinogen. Inhibition of DNA repair is one proposed mechanism to account for the co-carcinogenic actions of arsenic. We and others find that arsenite interferes with the function of certain zinc finger DNA repair proteins. Furthermore, we reported that zinc reverses the effects of arsenite in cultured cells and a DNA repair target protein, poly (ADP-ribose) polymerase-1. In order to determine whether zinc ameliorates the effects of arsenite on UVR-induced DNA damage in human keratinocytes and in an in vivo model, normal human epidermal keratinocytes and SKH-1 hairless mice were exposed to arsenite, zinc or both before solar-simulated (ss) UVR exposure. Poly (ADP-ribose) polymerase activity, DNA damage and mutation frequencies at the Hprt locus were measured in each treatment group in normal human keratinocytes. DNA damage was assessed in vivo by immunohistochemical staining of skin sections isolated from SKH-1 hairless mice. Cell-based findings demonstrate that ssUVR-induced DNA damage and mutagenesis are enhanced by arsenite, and supplemental zinc partially reverses the arsenite effect. In vivo studies confirm that zinc supplementation decreases arsenite-enhanced DNA damage in response to ssUVR exposure. From these data we can conclude that zinc offsets the impact of arsenic on ssUVR-stimulated DNA damage in cells and in vivo suggesting that zinc supplementation may provide a strategy to improve DNA repair capacity in arsenic exposed human populations. - Highlights: • Low levels of arsenite enhance UV-induced DNA damage in human keratinocytes. • UV-initiated HPRT mutation frequency is enhanced by arsenite. • Zinc supplementation offsets DNA damage and mutation frequency enhanced by arsenite. • Zinc-dependent reduction of arsenite enhanced DNA damage is confirmed in vivo.

Enhancement of exciton radiative recombination for In-doped ZnO nanowires with aluminum cylindrical micropillars

Energy Technology Data Exchange (ETDEWEB)

Wang, Jen-Cheng; Liang, Yu-Ting; Cheng, Fang-Ching; Fang, Chia-Hui; Chen, Hung-Ing; Tsai, Chung-Yuan [Graduate Institute of Electro-Optical Engineering and Department of Electronic Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan 333, Taiwan, ROC (China); Jiang, Joe-Air [Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China); Nee, Tzer-En, E-mail: neete@mail.cgu.edu.tw [Graduate Institute of Electro-Optical Engineering and Department of Electronic Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan 333, Taiwan, ROC (China)

2013-04-15

Zinc oxide (ZnO) has attracted intensive research effort in recent years, due to its unique properties and versatile applications. Recent work on the conservation of surface plasmon (SP) and light through period metal arrays has elucidated the propagation of SP resonance behavior. In this paper, we discuss the enhancement of exciton radiative recombination of the ZnO nanowires with Al cylindrical micropillars. Optical characterization of exciton interacted with SP resonance for indium-doped ZnO nanowires with Al cylindrical micropillars has been also investigated. From photoluminescence spectra of In-doped ZnO nanowires, it is found that the In-doped ZnO nanowires have a blue emission at 425 nm, which resulted from the ZnO band-to-band transition. Prior to the arrays of samples were annealed, a broad green emission centered at 500 nm was observed, which is attributed to ZnO native point defects. The relatively strong green band emission results from the radiative recombination that arises from the ionized oxygen vacancy and surface-defect related luminescence. Compare the In-doped ZnO on Si substrate, the enhancement of PL intensity for In-doped ZnO with deposited Al pattern film can be attributed to strong interaction with SP resonance and exciton over a broad temperature range. These experimental results indicate that Al cylindrical micropillars can significantly enhance carrier confinement and increase the quantum efficiency of In-doped ZnO/Al heterostructures due to the interaction of SP resonance between the In-doped ZnO nanowires and Al cylindrical micropillar structures, the surface-defect related luminescence, and the auxiliary test structures with variable micropillar parameters. -- Highlights: ► We examine the exciton radiative recombination of the ZnO nanowires. ► Al cylindrical micropillars affect the carrier recombination of ZnO/Al structures. ► The interaction of SP resonance between In-doped ZnO nanowire and Al pattern film. ► The carrier

Plasmonic enhancement of electroluminescence

Science.gov (United States)

Guzatov, D. V.; Gaponenko, S. V.; Demir, H. V.

2018-01-01

Here plasmonic effect specifically on electroluminescence (EL) is studied in terms of radiative and nonradiative decay rates for a dipole near a metal spherical nanoparticle (NP). Contribution from scattering is taken into account and is shown to play a decisive role in EL enhancement owing to pronounced size-dependent radiative decay enhancement and weak size effect on non-radiative counterpart. Unlike photoluminescence where local incident field factor mainly determines the enhancement possibility and level, EL enhancement is only possible by means of quantum yield rise, EL enhancement being feasible only for an intrinsic quantum yield Q0 red-orange range only. Independently of positive effect on quantum yield, metal nanoparticles embedded in an electroluminescent device will improve its efficiency at high currents owing to enhanced overall recombination rate which will diminish manifestation of Auger processes. The latter are believed to be responsible for the known undesirable efficiency droop in semiconductor commercial quantum well based LEDs at higher current. For the same reason plasmonics can diminish quantum dot photodegradation from Auger process induced non-radiative recombination and photoionization thus opening a way to avoid negative Auger effects in emerging colloidal semiconductor LEDs.

Multiparametric assessment of radiation effects for the individual radiation sensitivity estimation

International Nuclear Information System (INIS)

2006-01-01

The effects of low dose irradiation are highly relevant for radiation protection in the public. The sensitivity to clastogenic and tumorigenic effects of ionizing radiation (IR) varies considerably amongst individuals. Examples for genetically determined enhanced sensitivity are well known in some hereditary diseases: patients with chromosomal instability syndromes, Ataxia telangiectasia (A-T), Nijmegen Breakage Syndrome (NBS) and Bloom Syndrome (BS) show strongly enhanced sensitivity towards IR, severe immunodeficiencies, and a high incidence for developing leukemias and lymphomas. This obvious coincidence of enhanced radiosensitivity and tumor risk, and the frequently observed enhanced radiosensitivity of genetically non-defined tumor patients indicate that tumor patients may constitute a subpopulation with enriched genetical predisposition for enhanced radiosensitivity. Furthermore, a subpopulation of radiosensitive individuals may be part of the probably inconspicuous total population. For example, individuals heterozygous for the above mentioned genes (and possibly some other genes) show enhanced radiosensitivity if compared with the normal population. In general, heterozygous carriers of those hereditary deficiencies are clinically inconspicuous, but due an haploinsufficiency their tumour risk may be enhanced. This has been shown for mice carrying an heterozygous Nbs1 mutation (J.-Q. Wang, Lyon, pers. Communication). Our findings concerning enhanced radiation-induced chromosomal aberrations in heterozygous Nbs1 cell lines support this notion. The identification of high risk groups with enhanced radiosensitivity is therefore an important task for radioprotection. This project aimed at establishing a procedure which allows to test various cellular parameters as indicators for effects of radiation. A standard protocol for the isolation and cryoconservation of primary blood cells was developed. DNA repair analysis (Comet Assay) and radiation-induced apoptosis

Radioprotective properties of tocopherol succinate against ionizing radiation in mice

International Nuclear Information System (INIS)

Singh, V.K.; Singh, P.K.; Wise, S.Y.; Posarac, A.; Fatanmi, O.O.

2013-01-01

Threats of nuclear and other radiologic exposures have been increasing but no countermeasure for acute radiation syndrome has been approved by regulatory authorities. In prior publications we have demonstrated the efficacy of tocopherol succinate (TS) as a promising radiation countermeasure with the potential to protect against lethal doses of ionizing radiation exposure. The aim of this study was to gain further insight regarding how TS protects mice against a lethal dose of radiation. CD2F1 mice were injected subcutaneously with 400 mg/kg of TS, and 24 h later exposed to 60 Co γ-radiation. Intestinal tissues or spleen/thymus were harvested after irradiation and analyzed for CD68-positive inflammatory cells and apoptotic cells by immunostaining of jejunal cross-sections. Comet assay was used to analyze DNA damage in various tissues. Phospho-histone H3 (pH3) and the proliferating cell nuclear antigen (PCNA) were used as mitotic markers for immunostaining jejunal cross-sections. We observed that injecting TS significantly decreased the number of CD68-positive cells, DNA damage and apoptotic cells (bcl-associated X protein (BAX), caspase 3 and cleaved poly (ADP-ribose) polymerase-positive cells) as judged by various apoptotic pathway markers. TS treatment also increased proliferating cells in irradiated mice. Results of this study further support our contention that TS protects mice against lethal doses of ionizing radiation by inhibiting radiation-induced apoptosis and DNA damage while enhancing cell proliferation. (author)

Enhanced antitumor efficacy of folate-linked liposomal doxorubicin with TGF-β type I receptor inhibitor

International Nuclear Information System (INIS)

Taniguchi, Yukimi; Kawano, Kumi; Minowa, Takuya; Shimojo, Yuki; Maitani, Yoshie; Sugino, Takashi

2010-01-01

Tumor cell targeting of drug carriers is a promising strategy and uses the attachment of various ligands to enhance the therapeutic potential of chemotherapy agents. Folic acid is a high-affinity ligand for folate receptor, which is a functional tumor-specific receptor. The transforming growth factor (TGF)-β type I receptor (TβR-I) inhibitor A-83-01 was expected to enhance the accumulation of nanocarriers in tumors by changing the microvascular environment. To enhance the therapeutic effect of folate-linked liposomal doxorubicin (F-SL), we co-administrated F-SL with A-83-01. Intraperitoneally injected A-83-01-induced alterations in the cancer-associated neovasculature were examined by magnetic resonance imaging (MRI) and histological analysis. The targeting efficacy of single intravenous injections of F-SL combined with A-83-01 was evaluated by measurement of the biodistribution and the antitumor effect in mice bearing murine lung carcinoma M109. A-83-01 temporarily changed the tumor vasculature around 3 h post injection. A-83-01 induced 1.7-fold higher drug accumulation of F-SL in the tumor than liposome alone at 24 h post injection. Moreover F-SL co-administrated with A-83-01 showed significantly greater antitumor activity than F-SL alone. This study shows that co-administration of TβR-I inhibitor will open a new strategy for the use of folate receptor (FR)-targeting nanocarriers for cancer treatment. (author)

Surface Plasmon Enhanced Phosphorescent Organic Light Emitting Diodes

International Nuclear Information System (INIS)

Bazan, Guillermo; Mikhailovsky, Alexander

2008-01-01

The objective of the proposed work was to develop the fundamental understanding and practical techniques for enhancement of Phosphorescent Organic Light Emitting Diodes (PhOLEDs) performance by utilizing radiative decay control technology. Briefly, the main technical goal is the acceleration of radiative recombination rate in organometallic triplet emitters by using the interaction with surface plasmon resonances in noble metal nanostructures. Increased photonic output will enable one to eliminate constraints imposed on PhOLED efficiency by triplet-triplet annihilation, triplet-polaron annihilation, and saturation of chromophores with long radiative decay times. Surface plasmon enhanced (SPE) PhOLEDs will operate more efficiently at high injection current densities and will be less prone to degradation mechanisms. Additionally, introduction of metal nanostructures into PhOLEDs may improve their performance due to the improvement of the charge transport through organic layers via multiple possible mechanisms ('electrical bridging' effects, doping-like phenomena, etc.). SPE PhOLED technology is particularly beneficial for solution-fabricated electrophosphorescent devices. Small transition moment of triplet emitters allows achieving a significant enhancement of the emission rate while keeping undesirable quenching processes introduced by the metal nanostructures at a reasonably low level. Plasmonic structures can be introduced easily into solution-fabricated PhOLEDs by blending and spin coating techniques and can be used for enhancement of performance in existing device architectures. This constitutes a significant benefit for a large scale fabrication of PhOLEDs, e.g. by roll-to-roll fabrication techniques. Besides multieexciton annihilation, the power efficacy of PhOLEDs is often limited by high operational bias voltages required for overcoming built-in potential barriers to injection and transport of electrical charges through a device. This problem is especially

Low Z target switching to increase tumor endothelial cell dose enhancement during gold nanoparticle-aided radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Berbeco, Ross I., E-mail: rberbeco@partners.org; Detappe, Alexandre [Department of Radiation Oncology, Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115 (United States); Tsiamas, Panogiotis [Department of Radiation Oncology, St. Jude Children’s Hospital, Memphis, Tennessee 38105 (United States); Parsons, David; Yewondwossen, Mammo; Robar, James [Department of Radiation Oncology and Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 1V7 (Canada)

2016-01-15

Purpose: Previous studies have introduced gold nanoparticles as vascular-disrupting agents during radiation therapy. Crucial to this concept is the low energy photon content of the therapy radiation beam. The authors introduce a new mode of delivery including a linear accelerator target that can toggle between low Z and high Z targets during beam delivery. In this study, the authors examine the potential increase in tumor blood vessel endothelial cell radiation dose enhancement with the low Z target. Methods: The authors use Monte Carlo methods to simulate delivery of three different clinical photon beams: (1) a 6 MV standard (Cu/W) beam, (2) a 6 MV flattening filter free (Cu/W), and (3) a 6 MV (carbon) beam. The photon energy spectra for each scenario are generated for depths in tissue-equivalent material: 2, 10, and 20 cm. The endothelial dose enhancement for each target and depth is calculated using a previously published analytic method. Results: It is found that the carbon target increases the proportion of low energy (<150 keV) photons at 10 cm depth to 28% from 8% for the 6 MV standard (Cu/W) beam. This nearly quadrupling of the low energy photon content incident on a gold nanoparticle results in 7.7 times the endothelial dose enhancement as a 6 MV standard (Cu/W) beam at this depth. Increased surface dose from the low Z target can be mitigated by well-spaced beam arrangements. Conclusions: By using the fast-switching target, one can modulate the photon beam during delivery, producing a customized photon energy spectrum for each specific situation.

Combined Global MHD and Test-Particle Simulation of a Radiation Belt Storm: Comparing Depletion, Recovery and Enhancement with in Situ Measurements

Science.gov (United States)

Sorathia, K.; Ukhorskiy, A. Y.; Merkin, V. G.; Wiltberger, M. J.; Lyon, J.; Claudepierre, S. G.; Fennell, J. F.

2017-12-01

During geomagnetic storms the intensities of radiation belt electrons exhibit dramatic variability. In the main phase electron intensities exhibit deep depletion over a broad region of the outer belt. The intensities then increase during the recovery phase, often to levels that significantly exceed their pre-storm values. In this study we analyze the depletion, recovery and enhancement of radiation belt intensities during the 2013 St. Patrick's geomagnetic storm. We simulate the dynamics of high-energy electrons using our newly-developed test-particle radiation belt model (CHIMP) based on a hybrid guiding-center/Lorentz integrator and electromagnetic fields derived from high-resolution global MHD (LFM) simulations. Our approach differs from previous work in that we use MHD flow information to identify and seed test-particles into regions of strong convection in the magnetotail. We address two science questions: 1) what are the relative roles of magnetopause losses, transport-driven atmospheric precipitation, and adiabatic cooling in the radiation belt depletion during the storm main phase? and 2) to what extent can enhanced convection/mesoscale injections account for the radiation belt buildup during the recovery phase? Our analysis is based on long-term model simulation and the comparison of our model results with electron intensity measurements from the MAGEIS experiment of the Van Allen Probes mission.

Various perspectives of using radiation in applied entomology

International Nuclear Information System (INIS)

Seth, R.K.

2016-01-01

Nuclear energy has manifold benefits due to its use in various disciplines of entomology ranging from basic to applied fields. Despite the laissez-faire use of broad-spectrum insecticides, especially in the tropical and subtropical zones of the world, the food losses due to insect pests both at pre- and post-harvest level are significant. New innovative, effective and environmentally sound pest control tactics are therefore needed. Presently, biological and para-biological control programmes are receiving major prominence due to insecticidal ill effects on health and environment, and development of insecticidal resistance in pests. Radiation mediated sterile insect technique (SIT) is an automatic birth control and it is a part of an arsenal of environmentally-friendly control tactics against some key insect pests. Inherited (F 1 ) Sterility technique (a modified SIT), has been potentially developed for managing the serious lepidopteran pests. Various other applications of ionizing radiation include disinfestation of agro-commodities for quarantine and phytosanitary purposes, augmentation of biological control and radiation hormesis for enhancing the efficacy of useful insects. Gamma radiation from isotopic sources (Cobalt-60 or Caesium 137) is most often used, but high-energy electrons and X-rays are the other practical options. Application of nuclear techniques for controlling a variety of noxious insects may lead to improvement in production of crop and animal produce, and protection from the dreadful communicable diseases. Various perspectives of application of radiation as a tool in different entomological arenas are highlighted. (author)

Radiation efficacy and biological risk from whole-breast irradiation via intensity modulated radiation therapy (IMRT)

Science.gov (United States)

Desantis, David M.

Radiotherapy is an established modality for women with breast cancer. During the delivery of external beam radiation to the breast, leakage, scattered x-rays from the patient and the linear accelerator also expose healthy tissues and organs outside of the breast, thereby increasing the patient's whole-body dose, which then increases the chance of developing a secondary, radiation-induced cancer. Generally, there are three IntensityModulated Radiotherapy (IMRT) delivery techniques from a conventional linear accelerator; forward planned (FMLC), inverse planned 'sliding window' (DMLC), and inverse planned 'step-and-shoot' (SMLC). The goal of this study was to determine which of these three techniques delivers an optimal dose to the breast with the least chance of causing a fatal, secondary, radiation-induced cancer. A conventional, non-IMRT, 'Wedge' plan also was compared. Computerized Tomography (CT) data sets for both a large and small sized patient were used in this study. With Varian's Eclipse AAA algorithm, the organ doses specified in the revised ICRP 60 publication were used to calculate the whole-body dose. Also, an anthropomorphic phantom was irradiated with thermoluminescent dosimeters (TLD) at each organ site for measured doses. The risk coefficient from the Biological Effects of Ionizing Radiation (BEIR) VII report of 4.69 x 10-2 deaths per Gy was used to convert whole-body dose to risk of a fatal, secondary, radiation-induced cancer. The FMLC IMRT delivered superior tumor coverage over the 3D conventional plan and the inverse DMLC or SMLC treatment plans delivered clinically equivalent tumor coverage. However, the FMLC plan had the least likelihood of inadvertently causing a fatal, secondary, radiation-induced cancer compared to the inverse DMLC, SMLC, and Wedge plans.

Metformin enhances radiosensitivity via inhibition of DNA repair pathway in colorectal cancer

Energy Technology Data Exchange (ETDEWEB)

Jeong, Youn Kyoung; Kim, Mi Sook; Lee, Ji Young; Song, Kyung Hee; Choi, Kyul; Kim, Eun Ho; Ha, Hun Joo [Ewha Womans University, Seoul (Korea, Republic of)

2014-04-15

In this study, we provide a scientific rationale for the clinical application of metformin as a radiosensitizer in colorectal cancer. Colorectal cancer (CRC) is the third most common cancer in men and the second most common cancer in women worldwide. Currently, it is one of the commonest chemoradiotherapy worked better than the radiotherapy or chemotherapy in colorectal cancer. To enhance radiosensitivity of tumor cells for chemoradiotherapy, it is to use potential anticancer agents that act as radiosensitizers. Metformin, one of the most widely used antidiabetic drugs, has recently been associated with potential antitumorigenic effects. Our data shows that metformin combined with radiation enhances the efficacy of radiotherapy and down-regulates DNA repair proteins. Therefore, we provides a scientific rationale for the clinical application of metformin as a radiosensitizer in colorectal cancer.

Metformin enhances radiosensitivity via inhibition of DNA repair pathway in colorectal cancer

International Nuclear Information System (INIS)

Jeong, Youn Kyoung; Kim, Mi Sook; Lee, Ji Young; Song, Kyung Hee; Choi, Kyul; Kim, Eun Ho; Ha, Hun Joo

2014-01-01

In this study, we provide a scientific rationale for the clinical application of metformin as a radiosensitizer in colorectal cancer. Colorectal cancer (CRC) is the third most common cancer in men and the second most common cancer in women worldwide. Currently, it is one of the commonest chemoradiotherapy worked better than the radiotherapy or chemotherapy in colorectal cancer. To enhance radiosensitivity of tumor cells for chemoradiotherapy, it is to use potential anticancer agents that act as radiosensitizers. Metformin, one of the most widely used antidiabetic drugs, has recently been associated with potential antitumorigenic effects. Our data shows that metformin combined with radiation enhances the efficacy of radiotherapy and down-regulates DNA repair proteins. Therefore, we provides a scientific rationale for the clinical application of metformin as a radiosensitizer in colorectal cancer

Efficacy of Radiative Transfer Model Across Space, Time and Hydro-climates

Science.gov (United States)

Mohanty, B.; Neelam, M.

2017-12-01

The efficiency of radiative transfer model for better soil moisture retrievals is not yet clearly understood over natural systems with great variability and heterogeneity with respect to soil, land cover, topography, precipitation etc. However, this knowledge is important to direct and strategize future research direction and field campaigns. In this work, we present global sensitivity analysis (GSA) technique to study the influence of heterogeneity and uncertainties on radiative transfer model (RTM) and to quantify climate-soil-vegetation interactions. A framework is proposed to understand soil moisture mechanisms underlying these interactions, and influence of these interactions on soil moisture retrieval accuracy. Soil moisture dynamics is observed to play a key role in variability of these interactions, i.e., it enhances both mean and variance of soil-vegetation coupling. The analysis is conducted for different support scales (Point Scale, 800 m, 1.6 km, 3.2 km, 6.4 km, 12.8 km, and 36 km), seasonality (time), hydro-climates, aggregation (scaling) methods and across Level I and Level II ecoregions of contiguous USA (CONUS). For undisturbed natural environments such as SGP'97 (Oklahoma, USA) and SMEX04 (Arizona, USA), the sensitivity of TB to land surface variables remain nearly uniform and are not influenced by extent, support scales or averaging method. On the contrary, for anthropogenically-manipulated environments such as SMEX02 (Iowa, USA) and SMAPVEX12 (Winnipeg, Canada), the sensitivity to variables are highly influenced by the distribution of land surface heterogeneity and upscaling methods. The climate-soil-vegetation interactions analyzed across all ecoregions are presented through a probability distribution function (PDF). The intensity of these interactions are categorized accordingly to yield "hotspots", where the RTM model fails to retrieve soil moisture. A ecoregion specific scaling function is proposed for these hotspots to rectify RTM for

Radiation technology for enhancing agriculture productivity

International Nuclear Information System (INIS)

D'Souza, S.F.

2016-01-01

Radiations and radioisotopes are used in agricultural research to develop improved crop varieties, to manage insect pests, monitor fate of pesticides, to study fertilizer and plant micronutrient uptake and to preserve agricultural produce. This is one of the important fields of peaceful applications of atomic energy for societal benefit. Department of Atomic Energy (DAE) has contributed significantly in this area especially in the development of new mutant crop varieties which are benefitting the farmers in enhancing their productivity. With an effective blend of induced mutagenesis and recombination breeding, 42 new crop varieties developed at Bhabha Atomic Research Centre (BARC) have been released and Gazette notified by the Ministry of Agriculture, Government of India for commercial cultivation. These include 21 in oilseeds (15-groundnut, 3 mustard , 2 soybean, 1 sunflower), 19 in pulses (8-mungbean, 5-urdbean, 5-pigeonpea, 1-cowpea) and one each in rice and jute. Some of the desirable traits which have been bred through induced mutations in these crops include higher yields, improved quality traits, early maturity and resistance to biotic and abiotic stress. Several of these varieties have high patronage from the farming community and are grown extensively across the country. Groundnut varieties have given record yields in farmer's fields. Pulses such as mung, urid and tur are popular among farmers in view of their disease resistance and suitability to rice fallow situations. Many of the breeding programmes in national/state systems have been utilizing BARC varieties as parental materials/donors and have developed several other improved varieties using them. (author)

High LET radiation enhances apoptosis in mutated p53 cancer cells through Caspase-9 activation

International Nuclear Information System (INIS)

Yamakawa, Nobuhiro; Takahashi, Akihisa; Mori, Eiichiro; Imai, Yuichiro; Ohnishi, Ken; Kirita, Tadaaki; Ohnishi, Takeo; Furusawa, Yoshiya

2008-01-01

Although mutations in the p53 gene can lead to resistance to radiotherapy, chemotherapy and thermotherapy, high linear energy transfer (LET) radiation induces apoptosis regardless of p53 gene status in cancer cells. The aim of this study was to clarify the mechanisms involved in high LET radiation-induced apoptosis. Human gingival cancer cells (Ca9-22 cells) containing a mutated p53 (mp53) gene were irradiated with X-rays, C-ion (13-100 KeV/μm), or Fe-ion beams (200 KeV/μm). Cellular sensitivities were determined using colony forming assays. Apoptosis was detected and quantified with Hoechst 33342 staining. The activity of Caspase-3 was analyzed with Western blotting and flow cytometry. Cells irradiated with high LET radiation showed a high sensitivity with a high frequency of apoptosis induction. The relative biological effectiveness (RBE) values for the surviving fraction and apoptosis induction increased in a LET-dependent manner. Both RBE curves reached a peak at 100 KeV/μm, and then decreased at values over 100 KeV/μm. When cells were irradiated with high LET radiation, Caspase-3 was cleaved and activated, leading to poly (ADP-ribose) polymerase (PARP) cleavage. In addition, Caspase-9 inhibitor suppressed Caspase-3 activation and apoptosis induction resulting from high LET radiation to a greater extent than Caspase-8 inhibitor. These results suggest that high LET radiation enhances apoptosis by activation of Caspase-3 through Caspase-9, even in the presence of mp53. (author)

G2 checkpoint abrogator abates the antagonistic interaction between antimicrotubule drugs and radiation therapy

International Nuclear Information System (INIS)

Sui Meihua; Zhang Hongfang; Di Xiaoyun; Chang Jinjia; Shen Youqing; Fan Weimin