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Sample records for beta rays biological effects

  1. RBE [relative biological effectiveness] of tritium beta radiation to gamma radiation and x-rays analyzed by both molecular and genetic methods

    International Nuclear Information System (INIS)

    The relative biological effectiveness (RBE) of tritium beta radiation to 60Co gamma radiation was determined using sex-linked recessive lethals (SLRL) induced in Drosophila melanogaster spermatozoa as the biological effect. The SLRL test, a measure of mutations induced in germ cells transmitted through successive generations, yields a linear dose-response curve in the range used in these experiments. From these ratios of the slopes of the 3H beta and the 60 Co gamma radiation linear dose response curves, an RBE of 2.7 is observed. When sources of error are considered, this observation suggests that the tritium beta particle is 2.7 ± 0.3 times more effective per unit of energy absorbed in inducing gene mutations transmitted to successive generation than 60Co gamma radiation. Ion tracks with a high density of ions (high LET) are more efficient than tracks with a low ion density (low LET) in inducing transmissible mutations, suggesting interaction among products of ionization. Molecular analysis of x-ray induced mutations shows that most mutations are deletions ranging from a few base pairs as determined from sequence data to multi locus deletions as determined from complementation tests and Southern blots. 14 refs., 1 fig

  2. History, biological effects, and dosimetry of beta radiation

    International Nuclear Information System (INIS)

    There has been a renewed interest in the dosimetry of beta radiation, particularly in the nuclear power industry. This interest is fueled by the current regulatory concern over exposure to hot particles. Hot particles are small, usually microscopic particles of fuel material or activated products produced as a result of neutron activation in a nuclear reactor. In addition, these particles are characterized as having very high specific activity and being composed primarily of beta-emitting radionuclides. Of primary interest in the dosimetry of hot particles is the absorbed dose and/or dose equivalent to the basal layer of the skin. Current federal regulations, as well as international and national radiation protection standards, do not address adequately the exposure of small areas of the skin from a single point source. In this paper, the history of beta dosimetry is reviewed with an emphasis on early beta-radiation exposures, such as those associated with fallout from nuclear weapons. Beta burns due to the black rain associated with the Japanese bombings and fallout studies at the Nevada test site and in the Pacific testing area provided much of the earliest data. Many survivors of the Japanese bombings were exposed to high-intensity beta radiation when they were caught in a rainout of material that had been sucked up into the fireball of the weapon

  3. Indirect radio-chemo-beta therapy: a targeted approach to increase biological efficiency of x-rays based on energy

    Science.gov (United States)

    Oktaria, Sianne; Corde, Stéphanie; Lerch, Michael L. F.; Konstantinov, Konstantin; Rosenfeld, Anatoly B.; Tehei, Moeava

    2015-10-01

    Despite the use of multimodal treatments incorporating surgery, chemotherapy and radiotherapy, local control of gliomas remains a major challenge. The potential of a new treatment approach called indirect radio-chemo-beta therapy using the synergy created by combining methotrexate (MTX) with bromodeoxyuridine (BrUdR) under optimum energy x-ray irradiation is assessed. 9L rat gliosarcoma cells pre-treated with 0.01 μM MTX and/or 10 μM BrUdR were irradiated in vitro with 50 kVp, 125 kVp, 250 kVp, 6 MV and 10 MV x-rays. The cytotoxicity was assessed using clonogenic survival as the radiobiological endpoint. The photon energy with maximum effect was determined using radiation sensitization enhancement factors at 10% clonogenic survival (SER10%). The cell cycle distribution was investigated using flow cytometric analysis with propidium iodide staining. Incorporation of BrUdR in the DNA was detected by the fluorescence of labelled anti-BrUdR antibodies. The radiation sensitization enhancement exhibits energy dependence with a maximum of 2.3 at 125 kVp for the combined drug treated cells. At this energy, the shape of the clonogenic survival curve of the pharmacological agents treated cells changes substantially. This change is interpreted as an increased lethality of the local radiation environment and is attributed to supplemented inhibition of DNA repair. Radiation induced chemo-beta therapy was demonstrated in vitro by the targeted activation of combined pharmacological agents with optimized energy tuning of x-ray beams on 9 L cells. Our results show that this is a highly effective form of chemo-radiation therapy.

  4. Indirect radio-chemo-beta therapy: a targeted approach to increase biological efficiency of x-rays based on energy

    International Nuclear Information System (INIS)

    Despite the use of multimodal treatments incorporating surgery, chemotherapy and radiotherapy, local control of gliomas remains a major challenge. The potential of a new treatment approach called indirect radio-chemo-beta therapy using the synergy created by combining methotrexate (MTX) with bromodeoxyuridine (BrUdR) under optimum energy x-ray irradiation is assessed. 9L rat gliosarcoma cells pre-treated with 0.01 μM MTX and/or 10 μM BrUdR were irradiated in vitro with 50 kVp, 125 kVp, 250 kVp, 6 MV and 10 MV x-rays. The cytotoxicity was assessed using clonogenic survival as the radiobiological endpoint. The photon energy with maximum effect was determined using radiation sensitization enhancement factors at 10% clonogenic survival (SER10%). The cell cycle distribution was investigated using flow cytometric analysis with propidium iodide staining. Incorporation of BrUdR in the DNA was detected by the fluorescence of labelled anti-BrUdR antibodies. The radiation sensitization enhancement exhibits energy dependence with a maximum of 2.3 at 125 kVp for the combined drug treated cells. At this energy, the shape of the clonogenic survival curve of the pharmacological agents treated cells changes substantially. This change is interpreted as an increased lethality of the local radiation environment and is attributed to supplemented inhibition of DNA repair. Radiation induced chemo-beta therapy was demonstrated in vitro by the targeted activation of combined pharmacological agents with optimized energy tuning of x-ray beams on 9 L cells. Our results show that this is a highly effective form of chemo-radiation therapy. (paper)

  5. Effect on pancreatic beta cells and nerve cells by low let x-ray

    International Nuclear Information System (INIS)

    Cultured pancreatic beta cells and nerve cells, it is given normal condition of 10% FBS (fetal bovine serum), 11.1 mM glucose and hyperglycemia condition of 1% FBS, 30 mM glucose. For low LET X-ray irradiated with 0.5 Gy/hr dose-rate(total dose: 0.5 to 5 Gy). Survival rates were measured by MTT assay. When non irradiated, differentiated in the pancreatic beta cells experiment is hyperglycemia conditions survival rate compared to normal conditions survival rate seemed a small reduction. However increasing the total dose of X-ray, the survival rate of normal conditions decreased slightly compared to the survival rate of hyperglycemia conditions, the synergistic effect was drastically reduced. When non irradiated, undifferentiated in the nerve cells experiment is hyperglycemia conditions survival rate compared to normal conditions survival rate seemed a large reduction. As the cumulative dose of X-ray normal conditions and hyperglycemia were all relatively rapid cell death. But the rate of decreased survivals by almost parallel to the reduction proceed and it didn't show synergistic effect

  6. Biological effects of synchronous irradiation (soft X-rays and ultra-violet rays) on wheat

    International Nuclear Information System (INIS)

    The synchronous irradiation (soft X-rays, super soft X-rays) had a significant biological effect on wheat and barley when applied to seeds. Stripe chlorophyll defect was observed in M1 plants from the treated seeds with variation rate of 40%∼100%. The chlorophyll defect in barley could be classified into 4 types that were not observed in those treated with γ-rays irradiation and have not been reported. A wider spectrum of mutation with the highest of 9 types was found in M2 plants. The highest total mutation was 2.7∼3 times and beneficial mutation rate was 5.7 times of that with γ-rays treatments

  7. BETA-S, Multi-Group Beta-Ray Spectra

    International Nuclear Information System (INIS)

    1 - Description of program or function: BETA-S calculates beta-decay source terms and energy spectra in multigroup format for time-dependent radionuclide inventories of actinides, fission products, and activation products. Multigroup spectra may be calculated in any arbitrary energy-group structure. The code also calculates the total beta energy release rate from the sum of the average beta-ray energies as determined from the spectral distributions. BETA-S also provides users with an option to determine principal beta-decaying radionuclides contributing to each energy group. The CCC-545/SCALE 4.3 (or SCALE4.2) code system must be installed on the computer before installing BETA-S, which requires the SCALE subroutine library and nuclide-inventory generation from the ORIGEN-S code. 2 - Methods:Well-established models for beta-energy distributions are used to explicitly represent allowed, and 1., 2. - and 3. -forbidden transition types. Forbidden non-unique transitions are assumed to have a spectral shape of allowed transitions. The multigroup energy spectra are calculated by numerically integrating the energy distribution functions using an adaptive Simpson's Rule algorithm. Nuclide inventories are obtained from a binary interface produced by the ORIGEN-S code. BETA-S calculates the spectra for all isotopes on the binary interface that have associated beta-decay transition data in the ENSDF-95 library, developed for the BETA-S code. This library was generated from ENSDF data and contains 715 materials, representing approximately 8500 individual beta transition branches. 3 - Restrictions on the complexity of the problem: The algorithms do not treat positron decay transitions or internal conversion electrons. The neglect of positron transitions in inconsequential for most applications involving aggregate fission products, since most of the decay modes are via electrons. The neglect of internal conversion electrons may impact on the accuracy of the spectrum in the low

  8. The RBE of tritium-beta exposure for the induction of the adaptive response and apoptosis; cellular defense mechanisms against the biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    Adaption to radiation is one of a few biological responses that has been demonstrated to occur in mammalian cells exposed to doses of ionizing radiation in the occupational exposure range. The adaptive response has been well characterized in the yeast Saccharomyces cerevisiae, although the doses required to induce the response are higher than in mammalian cells. When yeast cells are primed with sublethal doses of gamma-radiation, they subsequently undergo an adaptive response and develop resistance to radiation, heat the chemical mutagens in a time and dose dependent manner. We have used this model system to assess the relative ability of tritium-beta radiation to induce the adaptive response the examined tritium-induced radiation resistance, thermal tolerance and suppression of mutation. The results show that sublethal priming doses of tritium caused yeast cells to develop resistance to radiation, heat, and a chemical mutagen MNNG. The magnitude and kinetics of the response, per unit dose, were the same for tritium and gamma-radiation. Therefore, the relative biological effectiveness (RBE) of tritium induction of the adaptive response was about 1.0. Apoptosis is a genetically programmed cell death or cell suicide. Cells damaged by radiation can be selectively removed from the population by apoptosis and therefore eliminated as a potential cancer risk to the organism. Since we have previously shown that apoptosis is a sensitive indicator of radiation damage in human lymphocytes exposed to low doses, we have used this endpoint to investigate the potency of tritium-beta radiation. Initially, tritium was compared to X-rays for relative effectiveness at inducing apoptosis. The results showed the lymphocytes irradiated in vitro with X-rays or tritium had similar levels of apoptosis per unit dose. Therefore the relative biology effectiveness of tritium for induction of apoptosis in human lymphocytes was also about 1. In the work presented here, we have demonstrated that

  9. The conflict between the biological effects of ultrasoft X-rays and microdosimetric measurements and application

    International Nuclear Information System (INIS)

    Approximate calculated microdosimetric spectra for these ultrasoft X-rays and other radiations will be presented. These will be compared with their observed biological effectiveness in cultured mammalian cells (inactivation and mutation to thioguanine resistance). The ultrasoft X-rays are found to be considerably more effective than 60Co γ-rays. These observed results are contrary to the usual predictions of microdosimetry which are based on the fact that the average event size (and zeta) of γ-rays is similar to that of aluminium X-rays and much greater than that of carbon X-rays. A well defined 'LET' cannot be assigned to the short tracks of such slow electrons but it is clear that they are at least as effective as long tracks ('track intersections') of helium ions of 'comparable' LET. This implies that the sites of damage are <=0.007μm and that radiation events of only about 14 ionizations (0.28 keV) are highly effective in producing biological effects. Since most types of radiation produce slow electrons and other short tracks (e.g. secondary electrons in γ-ray irradiations, delta-rays in heavy ion and neutron irradiations and very short recoils in neutron irradiation), the effectiveness of damage on this small scale has major implications for models of radiation action and for the relevance of those microdosimetric measurements which are based on total ionization in large simulated spheres of approximately 1μm. Some of these implications will be discussed and alternative approaches considered

  10. An interspecies comparison of the biological effects of an inhaled, relatively insoluble beta emitter

    International Nuclear Information System (INIS)

    Mice, rats, Syrian hamsters, and beagle dogs were exposed by inhalation to graded levels of 144Ce in relatively insoluble forms to demonstrate species similarities and differences regarding patterns of deposition, fate, dosimetry, and dose-response relationships. All animals were serially evaluated to determine lung burdens, held for life-span observation, necropsied at death, and examined histopathologically to characterize the lesions present and to determine the cause of death. The primary malignant lung tumors observed in rodents were predominantly squamous-cell carcinomas and adenocarcinomas, whereas those in dogs at earlier times were primarily hemangiosarcomas and those in dogs that died at later times were pulmonary carcinomas. The relationship between the incidence of lung cancer and absorbed beta dose to the lung differed among species. The results of modeling these data provide a better understanding of how the choice of species can influence the outcome of a life-span study. The data are used to estimate the risk of lung cancer in man from an inhaled beta-emitting radionuclide. 26 refs., 5 figs., 6 tabs

  11. Biological Effects of Gamma-Ray Bursts: Critical distances for severe damage on the biota

    CERN Document Server

    Galante, D; Galante, Douglas; Horvath, Jorge Ernesto

    2005-01-01

    We present in this work a unified, quantitative synthesis of analytical and numerical calculations of the effects caused on an Earth-like planet by a Gamma-Ray Burst (GRB), considering atmospheric and biological implications. The main effects of the illumination by a GRB are classified in four distinct ones and analyzed separately, namely the direct gamma radiation transmission, UV flash, ozone layer depletion and cosmic rays. The effectiveness of each of these effects is compared and lethal distances for significant biological damage are given for each one. We find that the first three effects have potential to cause global environmental changes and biospheric damages, even if the source is located at great distances (perhaps up to ~ 100 kpc). Instead, cosmic rays would only be a serious threat for very close sources. As a concrete example of a recorded similar event, the effects of the giant flare from SGR1806-20 of Dec 27, 2004 could cause on the biosphere are addressed. In spite of not belonging to the so...

  12. X-ray imaging and the skin: Radiation biology, patient dosimetry and observed effects

    International Nuclear Information System (INIS)

    A wide variety of radiation-induced deterministic skin effects have been observed after X-ray guided interventions ranging from mild effects, such as transient erythema or temporary epilation, to severe effects, such as desquamation and necrosis. Radiation biologists have identified, in addition to absorbed dose to the skin, other factors that strongly influence the type and severity of a skin reaction, including exposure-related factors (dose rate, fractionation, the size of the exposed area and its site), biological factors (age, oxygen status, capillary density, hormonal status and genetic factors) and ethnic differences. A peak entrance skin dose of 2 Gy is an arbitrary, but pragmatic, threshold for radiation-induced skin effects after X-ray guided interventions. Transient skin injury originating in the epidermis is not expected in the average patient population at peak entrance skin doses up to 6 Gy. Serious skin effects are not likely to occur in clinical practice when optimised X-ray equipment is used in combination with good techniques for fluoroscopy and imaging. However, this might not be true for patients with biological factors that are associated with an increased sensitivity for radiation-induced skin reactions. (authors)

  13. A semiconductor beta ray spectrometer

    International Nuclear Information System (INIS)

    Measurement of energy spectra of beta particles emitted from nuclei in beta-decay processes provides information concerning the mass difference of these nuclei between initial and final state. Moreover, experimental beta spectra yield information on the feeding of the levels in the daughter nucleus. Such data are valuable in the construction and checking of the level schemes. This thesis describes the design, construction, testing and usage of a detector for the accurate measurement of the mentioned spectra. In ch. 2 the design and construction of the beta spectrometer, which uses a hyper-pure germanium crystal for energy determination, is described. A simple wire chamber is used to discriminate beta particles from gamma radiation. Disadvantages arise from the large amounts of scattered beta particles deforming the continua. A method is described to minimize the scattering. In ch. 3 some theoretical aspects of data analysis are described and the results of Monte-Carlo simulations of the summation of annihilation radiation are compared with experiments. Ch. 4 comprises the results of the measurements of the beta decay energies of 103-108In. 87 refs.; 34 figs.; 7 tabs

  14. Calculation of {beta}-ray spectra. Odd-odd nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Tachibana, Takahiro [Waseda Univ., Tokyo (Japan). Advanced Research Center for Science and Engineering

    1996-05-01

    In order to study {beta}-ray of atomic nucleus, it is natural to consider {beta}-ray data fundamental and important. In a recent experiment, Rudstam measured {beta}-ray spectra from short term nuclear fission product species in 1990. It is an important check point in theoretical study on {beta}-ray to investigate if these experimental data can be reproduced by any theoretical calculation. As there are several spectrum studies of {beta}-ray through decay heat for its various properties due to the general theory of the {beta}-decay, little descriptions can be found. In even such studies, spectra under high excitation state of daughter species difficult to measure and apt to short experimental results were treated with combination spectra composed of experimental and calculated values such as substitution of a part of the general theory with calculated value. In this paper, the {beta} spectra supposed by only the general theory was reported without using such data combination in order to confirm effectiveness of the theory. In particular, this report was described mainly on the results using recent modification of odd-odd nucleus species. (G.K.)

  15. Relative biological effectiveness (RBE) of fission neutrons and gamma rays at occupational exposure levels

    International Nuclear Information System (INIS)

    The pathologic consequences of exposure to 60 equal once-weekly doses of fission neutron or 60Co gamma rays have been subjected to dose-response analyses for the purposes of generating relative biological effectiveness (RBE) values for the major causes of death of for tumor occurrences. Cumulative probabilities of death or occurrence were generated for 15 categories of neoplastic disease for the time interval of 800--999 days since first exposure. These probabilities were developed for each dose, sex, and radiation quality, and a dose-response analysis was applied to derive linear risk coefficients of death or occurrence. 40 refs., 16 figs., 9 tabs

  16. Biological effects of turf bamboo by 137Cs γ-rays irradiation

    International Nuclear Information System (INIS)

    137Cs γ-rays was used to treat bamboo rhizome or culture of turf bamboo, and to evaluate the biological was studied. It showed that low dose of irradiation had no effect on bud germination, high dose of irradiation delayed the bud germination. Sasa pygmaea was more resistant to γ-rays irradiation, and the lethal dose of Sasa culture was 20 ∼ 30 Gy. For Sasa fortunei culture the lethal dose was less than 20 Gy; and the lethal dose of bamboo rhizome for Indocalamus latifolius was 10 ∼ 20 Gy, for other 3 species of bamboo, the lethal dose was more than 80 Gy. The morphological feature of Sasa pygmaea, or Indocalamus latifolius, or Indocalamus decorous after irradiation was not obvious, but the white strip in its green leaves of Shibataea chinensis irradiated with 5 and 10 Gy was observed. (authors)

  17. The Beta-Model Problem: The Incompatibility of X-ray and Sunyaev-Zeldovich Effect Model Fitting for Galaxy Clusters

    OpenAIRE

    Hallman, Eric J.; Burns, Jack O.; Motl, Patrick M; Michael L. Norman

    2007-01-01

    We have analyzed a large sample of numerically simulated clusters to demonstrate the adverse effects resulting from use of X-ray fitted beta-model parameters with Sunyaev-Zeldovich effect (SZE) data. There is a fundamental incompatibility between model fits to X-ray surface brightness profiles and those done with SZE profiles. Since observational SZE radial profiles are in short supply, the X-ray parameters are often used in SZE analysis. We show that this leads to biased estimates of the int...

  18. The Beta-Model Problem: The Incompatibility of X-ray and Sunyaev-Zeldovich Effect Model Fitting for Galaxy Clusters

    CERN Document Server

    Hallman, Eric J; Motl, Patrick M; Norman, Michael L

    2007-01-01

    We have analyzed a large sample of numerically simulated clusters to demonstrate the adverse effects resulting from use of X-ray fitted beta-model parameters with Sunyaev-Zeldovich effect (SZE) data. There is a fundamental incompatibility between model fits to X-ray surface brightness profiles and those done with SZE profiles. Since observational SZE radial profiles are in short supply, the X-ray parameters are often used in SZE analysis. We show that this leads to biased estimates of the integrated Compton y-parameter inside r_{500} calculated from clusters. We suggest a simple correction of the method, using a non-isothermal beta-model modified by a universal temperature profile, which brings these calculated quantities into closer agreement with the true values.

  19. High energy beta rays and vectors of Bilharzia and Fasciola

    International Nuclear Information System (INIS)

    Preliminary investigations of the effects of high energy beta rays on Lymnea natalensis, the snail vector of Schistosoma haematobium have been conducted. Results show that in both stream and tap water, about 70% of the snails die when irradiated for up to 18 hours using a 15m Ci Sr-90 beta source. The rest of the snails die without further irradiation in 24 hours. It may then be possible to control the vectors of Bilharzia and Fasciola by using both the direct and indirect effects of high energy betas. (author)

  20. High energy beta rays and vectors of Bilharzia and Fasciola

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, J.J.; Akpa, T.C.; Dim, L.A.; Ogunsusi, R.

    1988-01-01

    Preliminary investigations of the effects of high energy beta rays on Lymnea natalensis, the snail vector of Schistosoma haematobium have been conducted. Results show that in both stream and tap water, about 70% of the snails die when irradiated for up to 18 hours using a 15m Ci Sr-90 beta source. The rest of the snails die without further irradiation in 24 hours. It may then be possible to control the vectors of Bilharzia and Fasciola by using both the direct and indirect effects of high energy betas.

  1. The imaging pin detector - a simple and effective new imaging device for soft x-rays and soft beta emissions

    International Nuclear Information System (INIS)

    The development of a new bidimensional imaging detector system for soft X and beta radiations is reported. Based on the detection of the differential induction signals on pickup electrodes placed around a point anode in a gas avalanche detector, the system described has achieved a spatial resolution of better than 1mm fwhm over a field of 30mm diameter while preserving excellent pulse height resolution. The present device offers considerable potential as a cheap and robust imaging system for applications in X-ray diffraction and autoradiography. (author)

  2. The imaging pin detector. A simple and effective new imaging device for soft X-rays and soft beta emissions

    International Nuclear Information System (INIS)

    The development of a new bidimensional imaging detector system for soft X- and beta radiations is reported. Based on the detection of the differential induction signals on pickup electrodes placed around a point anode (or pin) in a gas avalanche detector, the system described has achieved a spatial resolution of better than 1 mm fwhm over a field of 30 mm diameter while preserving excellent pulse height resolution (20% fwhm for 5.9 keV X-rays). While limited to applications in which fairly low counting rates are encountered (<5 kHz) the present device offers considerable potential as a cheap and robust imaging system for applications in X-ray diffraction and autoradiography. (orig.)

  3. Biological effects induced by low energy x-rays: effects of nanoparticles

    Science.gov (United States)

    Liehn, S.; Le Sech, C.; Porcel, E.; Zielbauer, B.; Habib, J.; Kazamias, S.; Guilbaud, O.; Pittman, M.; Ros, D.; du Penhoat, M.-A. Hervé; Touati, A.; Remita, H.; Lacombe, S.

    2009-08-01

    Samples of plasmid DNA were irradiated with pulsed 18.9 nm radiation originating from a Mo X-ray laser (XRL) pumped in GRIP configuration at the LASERIX facility. Up to 21 000 pulses were delivered with a repetition rate of 10 Hz and average pulse energy of 200 nJ. Radiosensitization by two different platinum compounds (platinum terpyridine chloride (PtTC) and platinum nanoparticles) were investigated. SSB and DSB yields were measured using agarose gel electrophoresis. The occurrence of single and double strand breaks not present in controls having undergone the same treatment except for the XRL irradiation can be seen as a clear effect of the XRL irradiation. This confirms the role of direct effects in DNA damages as previously seen with low energy ions and electrons (1) (2). In addition we demonstrate a DNA breaks enhancement in the presence of platinum. No difference of enhancement was seen between these two radiosensitizers.

  4. Gamma rays as an effective tool for removing undesirable color without adverse changes in biological activities of red beet extracts

    Science.gov (United States)

    Lee, Seung Sik; Lee, Eun Mi; Hong, Sung Hyun; Bai, Hyoung-Woo; Lee, In Chul; Chung, Byung Yeoup

    2012-08-01

    The ethanolic extracts of red beet (Beta vulgaris L.) hairy root were used to investigate the removal of color and improvement of biological activity for enhanced industrial applications. The extracts were exposed to gamma rays ranging from 2.5 to 30 kGy. The red beet hairy root is composed of two major red-colorants, betanin and isobetanin. Gamma ray radiation at 5 kGy remarkably reduced the levels of the major colorants by 94% and the reddish color was eliminated by doses greater than 10 kGy. Color removal was likely due to the gamma ray radiolysis of ethanol. Although details on the mechanism responsible for the decay of the chromophore have not been entirely determined, our results suggest that the free radicals that are produced during this process are capable of destroying the chromophore group in isobetanin, thus bleaching the substrate solution. In spite of the degradation of the major colorants, the biological activities of constituents of the extract such as DPPH radical scavenging and tyrosinase inhibition were negligibly affected by the gamma ray radiation up to 20 kGy. The antioxidant activity was 92.7% in control samples and 90.0-92.0% in irradiated samples (2.5-20 kGy), and a slight decrease to 87.5% was observed for gamma ray radiation at 30 kGy. In addition, tyrosinase inhibition activity has also the same pattern; the activity is slightly increased from 50.7% of control to 49.1-52.8% of irradiated samples (2.5-20 kGy) with a 46.8% at 30 kGy.

  5. Gamma rays as an effective tool for removing undesirable color without adverse changes in biological activities of red beet extracts

    International Nuclear Information System (INIS)

    The ethanolic extracts of red beet (Beta vulgaris L.) hairy root were used to investigate the removal of color and improvement of biological activity for enhanced industrial applications. The extracts were exposed to gamma rays ranging from 2.5 to 30 kGy. The red beet hairy root is composed of two major red-colorants, betanin and isobetanin. Gamma ray radiation at 5 kGy remarkably reduced the levels of the major colorants by 94% and the reddish color was eliminated by doses greater than 10 kGy. Color removal was likely due to the gamma ray radiolysis of ethanol. Although details on the mechanism responsible for the decay of the chromophore have not been entirely determined, our results suggest that the free radicals that are produced during this process are capable of destroying the chromophore group in isobetanin, thus bleaching the substrate solution. In spite of the degradation of the major colorants, the biological activities of constituents of the extract such as DPPH radical scavenging and tyrosinase inhibition were negligibly affected by the gamma ray radiation up to 20 kGy. The antioxidant activity was 92.7% in control samples and 90.0–92.0% in irradiated samples (2.5–20 kGy), and a slight decrease to 87.5% was observed for gamma ray radiation at 30 kGy. In addition, tyrosinase inhibition activity has also the same pattern; the activity is slightly increased from 50.7% of control to 49.1–52.8% of irradiated samples (2.5–20 kGy) with a 46.8% at 30 kGy. - Highlights: ► Gamma ray radiation at 5 kGy remarkably reduced the levels of the major colorants. ► The reddish color was eliminated by doses greater than 10 kGy. ► The biological activities of constituents of the extract were negligibly affected by the gamma ray.

  6. Biological effects

    International Nuclear Information System (INIS)

    Following an introduction into the field of cellular radiation effect considering the most important experimental results, the biological significance of the colony formation ability is brought out. The inactivation concept of stem cells does not only prove to be good, according to the present results, in the interpretation of the pathogenesis of acute radiation effects on moult tissue, it also enables chronicle radiation injuries to be interpreted through changes in the fibrous part of the organs. Radiation therapy of tumours can also be explained to a large extent by the radiation effect on the unlimited reproductiveness of tumour cells. The more or less similar dose effect curves for healthy and tumour tissue in practice lead to intermittent irradiation. The dependence of the intermittent doses and intervals on factors such as Elkind recovery, synchronisation, redistribution, reoxygenation, repopulation and regeneration are reviewed. (ORU/LH)

  7. Influence of variations in dose and dose rates on biological effects of inhaled beta-emitting radionuclides

    International Nuclear Information System (INIS)

    The biological effects of inhaled β-emitting radionuclides, 90Y, 91Y, 144Ce and 90Sr, are being investigated in beagle dogs that received single acute exposures at 12 to 14 months of age. The aerosols studied have included 91YC13,144CeC13, 90SrC12, and 90Y, 91Y, 144Ce or 90Sr in aluminosilicate particles. Thus, 91YCl3, 144CeCl3 and the aluminosilicate containing radionuclide particles all resulted in significant exposures to lung; 91YC13, 144CeC13 an 90SrC12 resulted in significant exposures to bone; 91YC13 and 144 CeC13 resulted in significant exposures to liver. The higher initial doserate exposures have been more effective than low dose-rate exposures on a per-rad basis in producing early effects. To date (144CeO2, it was observed that, on a μCi initial lung burden per kilogram body weight basis, mice did not develop pulmonary tumours whereas beagle dogs did. To fid out the reason for this observation mice have been repeatedly exposed by inhalation to 144CeO2 to maintain lung burdens of 144Ce that resulted in radiation dose rates similar to that observed in beagle dogs. Several of the repeatedly exposed mice developed malignant pulmonary tumours. Thus, with similar dose rates and cumulative doses to the lung, mice and dogs responded in a similar manner to chronic β radiation

  8. Evaluation of induced radioactivity in 10 MeV-Electron irradiated spices, (2); [beta]-ray counting

    Energy Technology Data Exchange (ETDEWEB)

    Katayama, Tadashi; Furuta, Masakazu; Shibata, Setsuko; Matsunami, Tadao; Ito, Norio; Mizohata, Akira; Toratani, Hirokazu (Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology); Takeda, Atsuhiko

    1994-02-01

    In order to check radioactivity of beta-emmitters produced by ([gamma], n) reactions which could occur at energies up to 10 MeV, black pepper, white pepper, red pepper, ginger and turmeric were irradiated with 10 MeV electron from a linear accelerator to a dose of 100 kGy. Beta-rays were counted using a 2[pi] gas flow counter and a liquid scintillation counter. Any induced radioactivity could not be detected in irradiated samples. When inorganic compounds containing the nuclides in the list were artificially added in the samples and were irradiated, the [beta]-activities were detected. From the amount of observed radioactivities of [beta]-emmitters produced in the compounds as photonuclear products, it is concluded that the induced radioactivity in natural samples by 10 MeV-electron irradiation were far smaller than natural radioactivity from [sup 40]K contained in the samples and, hence, its biological effects should be negligible. (author).

  9. Backscatter radiation at tissue-titanium interfaces; Biological effects from diagnostic 65 kVp X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Rosengren, B. (Department of Radiation Sciences, Uppsala University (Sweden) Dept. of Oncology, University Hospital, Bergen (Norway)); Wulff, L. (Dept. of Oral and Maxillofacial Surgery, Central Hospital, Boden (Sweden)); Carlsson, E. (Department of Radiation Sciences, Uppsala University (Sweden)); Carlsson, J. (Department of Radiation Sciences, Uppsala University (Sweden)); Strid, K.G. (Dept. of Handicap Research, Goeteborg Univ. (Sweden)); Montelius, A. (Dept. of Hospital Physics, University Hospital, Uppsala (Sweden))

    1993-01-01

    The induced secondary electrons from a metal surface by diagnostic X-rays are thought to contribute to cell damage near the tissue-metal boundaries of metal implants. Titanium implants are becoming increasingly more popular for tissue reconstructions and it is rather often desirable to take radiographs of the operated area. In this study we compared the biological effects of radiation on cultured mammalian test cells grown on titanium plates with the radiation effects on cells that were grown on plastic control plates. In order to study the acute radiation effects on cell growth it was necessary to work with rather high radiation doses (0.7-5 Gy). Photon energies, suitable for diagnostic radiography in odontology, 65 kV, were applied. We found that the cells grown on titanium plates were, in terms of the applied dose in the surrounding culture medium, more sensitive to the irradiations than the cells growing on plastic plates. The survival curve for the cells on titanium had a steeper slope, showed no shoulder in the low-dose region and looked like curves normally obtained for high LET radiation. It was not possible to resolve to what degree the titanium-dependent changes were due to an increased dose near the titanium surface or to a change in the radiobiological effectiveness. Although there was a significant decrease in cellular survival near the metal, postoperative intraoral radiography after titanium implantations need not be excluded. The maximal doses given in odontological X-ray examinations are less than 1 mGy and, if the results in this study are applied, the biological effects near the titanium implant will correspond to biological effects in soft tissue of doses less than 20 mGy which is lower than the doses that give acute effects. The risk of acute healing disturbances are significant only at much higher radiation doses. (orig.).

  10. Biological effects of space flight, γ-ray irradiation and their combinations with in vitro culture on rice

    International Nuclear Information System (INIS)

    Biological effects of space flight on rice were studied by placing the dry seeds of indica variety Zhongyouzao 3 in a returnable satellite and compared with those treated by different doses of γ-ray irradiation. The results showed that space flight produced evidently lighter physiological damages to seedling growth and spikelet fertility than γ-ray irradiation in M1 generation, and induced lower mutation frequency of chlorophyll deficiency, plant height and heading date than 300 Gy of γ-ray treatment in M2 generation. Mature embryo culture of the seeds exposed to space environments resulted in considerable increase in mutation frequency of chlorophyll deficiency and plant height. After irradiation of calli from the space-mutagenized seeds, percentage of calli with green spots and green plantlets decreased, and mutation frequency of chlorophyll deficiency, plant height and heading date not only exceeded the sum of that induced by single treatment of space flight and in vitro mutagenesis, but also was higher than that of 300 Gy of γ-ray irradiation

  11. Conformation, molecular packing and field effect mobility of regioregular beta,beta'-dihexylsexithiophiophene

    DEFF Research Database (Denmark)

    Kiriy, N.; Kiriy, A.; Bocharova, V.;

    2004-01-01

    (SEM), atomic force microscopy (AFM), and X-ray techniques. Absorption spectra of a beta,beta'-DH6T spin-cast film indicate the planar conformation of the aromatic backbone. SEM and AFM reveal the formation of an ordered lamellar phase. As a single-crystal X-ray study shows, beta,beta'-DH6T exhibits......Improved synthesis, charge carrier mobility, conformation, crystalline structure, and molecular packing of the regiochemically pure 4',3""-dihexyl-2,2';5',2";5",2 "';5"',2"";5"",2""'-sexithiophene (beta,beta'-DH6T) are reported. The sum of charge carrier mobilities of beta,beta'-DH6T measured...... by the pulse-radiolysis time-resolved microwave conductivity (PR-TRMC) technique was found to be Sigmamu(min) = 3.9 x 10(-3) cm(2) V-1 s(-1), which is comparable with the PR-TRMC mobility found for alpha,omega-DH6T. The field-effect mobility (FEM) of beta,beta'-DH6T was found to be on the order of 10(-5) cm(2...

  12. Effect of tea catechins on the structure of lipid membrane and beta ray-induced lipid peroxidation

    International Nuclear Information System (INIS)

    Tea catechins show various pharmacological effect and is known as one of useful antioxidants. We have reported that tea catechins showed inhibiting effect to β-ray induced lipid peroxidation in the low concentration region up to 5 x 10-5 M in the aqueous liposome suspension system. The initiating radical was thought to be the hydroxyl radical (·OH) formed by the decomposition of' water molecules near the membrane surface. Catechins are adsorbed on the membrane surface and scavenge ·OH which enters in the membrane and initiates lipid peroxidation. Inhibiting ability depended on the degree of partition between membrane and water, and this was one of the evidences of the propriety of the model. In this paper, we report the effect of tea catechins on the lipid peroxidation using a spin probe method and the observation of the figure of the liposome with transmission electron microscope in high concentration region between 5 x 10-5 and 1 x 10-2 M. A spin probe 16NS (16-doxylstearic acid) was mixed with egg yolk phosphatidylcholine, and the lipid was dispersed in phosphate buffer solution forming unilamellar liposome. Catechins, (-)-epicatechin (EC), (-)-epicatechin gallate (ECg), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCg), of various concentrations and then the tritiated water were added to the suspension. Reaction was proceeded at 310 K, and the inhibiting activity was compared using ID50 at which absorbed dose the intensity of 16NS decreases to a half of the initial value. Liposomes were stained with 3% solution of uranium acetate and observed by Hitachi H-7500 Electron Microscope. Fig. 1 shows the concentration dependence of ID50 of catechins. EC and ECg showed inhibiting effect in whole region and looked to converge. But EGCg had the maximum point. Below the point, it showed the strongest activity among four catechins. EGC showed slow decrease in whole region. We considered these results as follows. Catechins possessing gallate group have

  13. Gamma-Ray Bursts and the Earth: Exploration of Atmospheric, Biological, Climatic and Biogeochemical Effects

    CERN Document Server

    Thomas, B C; Jackman, C H; Laird, C M; Medvedev, M V; Stolarski, R S; Gehrels, N; Cannizzo, J K; Hogan, D P; Ejzak, L M; Thomas, Brian C.; Melott, Adrian L.; Jackman, Charles H.; Laird, Claude M.; Medvedev, Mikhail V.; Stolarski, Richard S.; Gehrels, Neil; Cannizzo, John K.; Hogan, Daniel P.; Ejzak, Larissa M.

    2005-01-01

    Gamma-Ray Bursts (GRBs) are likely to have made a number of significant impacts on the Earth during the last billion years. We have used a two-dimensional atmospheric model to investigate the effects on the Earth's atmosphere of GRBs delivering a range of fluences, at various latitudes, at the equinoxes and solstices, and at different times of day. We have estimated DNA damage levels caused by increased solar UVB radiation, reduction in solar visible light due to $\\mathrm{NO_2}$ opacity, and deposition of nitrates through rainout of $\\mathrm{HNO_3}$. For the ``typical'' nearest burst in the last billion years, we find globally averaged ozone depletion up to 38%. Localized depletion reaches as much as 74%. Significant global depletion (at least 10%) persists up to about 7 years after the burst. Our results depend strongly on time of year and latitude over which the burst occurs. We find DNA damage of up to 16 times the normal annual global average, well above lethal levels for simple life forms such as phytopl...

  14. Biological effects of radiation and dosimetry in X-ray diagnostics of children

    International Nuclear Information System (INIS)

    The chest radiograms represent the basic radiological examinations of thorax. The basis for radiation protection especially in pediatrics is the exact determination of doses. The risk estimation of genome damages can be received in human peripheral blood lymphocytes using alkaline version of Comet Assay. The aim of this work was assessment and quantification of the level of DNA damage in peripheral blood lymphocytes of children during airways X-ray examinations of chest and to compare data to the dose of exposure. Doses were determined using thermoluminescence (TL) dosimetry and radiophotoluminescent (RPL) glass dosimetry system. Twenty children with pulmonary diseases, ages between 5 and 14 years were assessed. Dose measurements were conducted for poster-anterior (PA) projection on the forehead, thyroid gland, gonads, chest and back. We used a 150 kV Shimadzu CH-200 M X-ray unit. Peripheral blood samples were taken from children after and prior to X-ray exposure and were examined with the alkaline Comet Assay. Comet Assay is one of the standard techniques for assessing genome damage with variety applications in genotoxicity testing as well as fundamental research in DNA damage and repair. As a measure of DNA damage tail length was used, calculated from the centre of the head and presented in micrometers (μm). Mean value of group after irradiation was 14.04 ± 1.74 as opposed to mean value of group before irradiation that was 13.15 ± 1.33. Differences between mean tail lengths were statistically significant (P<0.05, ANOVA). In addition, correlation was found between doses in primary beam (measured on the back) and the ratio of tail length (DNA damage) before and after irradiation. Doses measured with TL and RPL dosimeters showed satisfactory agreement and both dosimetry methods are suitable for dosimetric measurements in X-ray diagnostics. (author)

  15. Biological effects of radiation

    International Nuclear Information System (INIS)

    This fourth chapter presents: cell structure and metabolism; radiation interaction with biological tissues; steps of the production of biological effect of radiation; radiosensitivity of tissues; classification of biological effects; reversibility, transmissivity and influence factors; pre-natal biological effects; biological effects in therapy and syndrome of acute irradiation

  16. RBE of tritium beta rays for causes of death other than myeloid leukemia in male CBA/H mice

    International Nuclear Information System (INIS)

    Causes of death were examined for 5,206 male CBA/H mice which had previously been treated with tritiated water or with X rays at comparable doses and comparable dose rates. Data on induced myeloid leukemia had been examined in detail in a previous report. The purpose of the present study was to examine the relative biological effectiveness of tritium beta rays for causes of death other than mye-loid leukemia. However, no consistent values for the tritium relative biological effectiveness were obtained. The values were spread over a wide range for different endpoints and were generally less reliable than those for induction of myeloid leukemia. A surprising decrease in time to death of animals without tumours was observed in the irradiated groups of mice. This observation suggests that a detailed review of recent data on non-specific life shortening in irradiated animals and humans might be useful

  17. Effect of beta blockade and beta stimulation on stage fright.

    Science.gov (United States)

    Brantigan, C O; Brantigan, T A; Joseph, N

    1982-01-01

    Stage fright, physiologically the "fight or flight" reaction, is a disabling condition to the professional musician. Because it is mediated by the sympathetic nervous system, we have investigated the effects of beta blockade on musical performance with propranolol in a double blind fashion and the effects of beta stimulation using terbutaline. Stage fright symptoms were evaluated in two trials, which included a total of 29 subjects, by questionnaire and by the State Trai Anxiety Inventory. Quality of musical performance was evaluated by experienced music critics. Beta blockade eliminates the physical impediments to performance caused by stage fright and even eliminates the dry mouth so frequently encountered. The quality of musical performance as judged by experienced music critics is significantly improved. This effect is achieved without tranquilization. Beta stimulating drugs increase stage fright problems, and should be used in performing musicians only after consideration of the detrimental effects which they may have on musical performance. PMID:6120650

  18. The Beta Problem: The Incompatibility of X-ray and Sunyaev-Zeldovich Model Fitting

    Science.gov (United States)

    Burns, Jack O.; Hallman, E.; Motl, P.; Norman, M.

    2006-12-01

    We describe an analysis of a large sample of numerically simulated clusters which demonstrates the effects of using X-ray fitted beta-model parameters with Sunyaev-Zeldovich effect (SZE) data. There is a fundamental incompatibility between beta-model fits to X-ray surface brightness profiles and those done with SZE profiles. Since observational SZE radial profiles are in short supply, the X-ray parameters are often used in SZE analysis. We show that this leads to biased estimates of the integrated Compton y-parameter inside r500 and the value of the Hubble constant calculated from clusters. We suggest a simple scaling of the X-ray beta-model parameters which brings these calculated quantities into close agreement with the true values.

  19. Biological and genetic effects of combined treatments of sodium azide, gamma rays and EMS in barley

    International Nuclear Information System (INIS)

    Dry seeds of diploid barley were subjected to mutagenic treatments of sodium azide, gamma rays and EMS alone or in combination. Damage (reduction in seedling height, plant height and fertility), the frequency of chimeras in the M1 generation, and the frequency of chlorophyll-deficient mutations as well as morphological mutations in the M2 generation induced by combined treatments were greater than those by either of the single treatments. Synergistic increase in the frequency of chimeras, chlorphyll-deficient mutations and morphological mutations were observed in both sodium azide post-irradiation treatments and pre-EMS treatments; interaction among the mutagens in the treatment combinations on M1 damage was generally subtractive. An 8- to 16-hr soaking period of irradiated seeds in distilled water prior to sodium azide treatment significantly increased chlorophyll mutation frequency, as compared to that from the non-soaking treatment. Damage and frequency of chimeras, chlorophyll mutations and morphological mutations were consistently reduced by the soaking treatment in sodium azide plus EMS treatments. (author)

  20. Biological effect and tumor risk of diagnostic x-rays. The ''war of the theories''

    International Nuclear Information System (INIS)

    Since the introduction of ionizing radiation as a treatment and diagnostic tool in humans, scientists have been trying to estimate its side effects and potential health risks. There is now ample evidence for the principal existence of a direct relationship between higher doses and the risks of side effects. Most of the uncertainties lie in the field of low-dose effects especially with respect to the risk of cancer induction. Low-dose effects are usually of relevance in diagnostic medicine while high-dose radiation effects are typically observed after radiotherapeutic treatment for cancer or after nuclear accidents. The current state of the ''war of theories'' may be summarized as follows: one group of scientists and health regulatory officials favors the hypothesis that there is no threshold dose, i.e. the linear-no-threshold hypothesis (LNT) of radiation which can be regarded as safe. On the contrary, the critics of this hypothesis suggest that the risks of doses below 50 mSv are not measurable or even of clinical relevance and are not adequately described by a linear dose-response relationship. The aim of this article is to summarize the major unresolved issues in this field. Arguments are presented why the validity of the LNT model in the low-dose range should be regarded as at least inconsistent and is thus questionable. (orig.)

  1. X-ray microtomography in biology

    CERN Document Server

    Mizutani, Ryuta

    2016-01-01

    Progress in high-resolution x-ray microtomography has provided us with a practical approach to determining three-dimensional (3D) structures of opaque samples at micrometer to submicrometer resolution. In this review, we give an introduction to hard x-ray microtomography and its application to the visualization of 3D structures of biological soft tissues. Practical aspects of sample preparation, handling, data collection, 3D reconstruction, and structure analysis are described. Furthermore, different sample contrasting methods are approached in detail. Examples of microtomographic studies are overviewed to present an outline of biological applications of x-ray microtomography. We also provide perspectives of biological microtomography as the convergence of sciences in x-ray optics, biology, and structural analysis.

  2. PhytoBeta imager: a positron imager for plant biology

    International Nuclear Information System (INIS)

    Several positron emitting radioisotopes such as 11C and 13N can be used in plant biology research. The 11CO2 tracer is used to facilitate plant biology research toward optimization of plant productivity, biofuel development and carbon sequestration in biomass. Positron emission tomography (PET) imaging has been used to study carbon transport in live plants using 11CO2. Because plants typically have very thin leaves, little medium is present for the emitted positrons to undergo an annihilation event. The emitted positrons from 11C (maximum energy 960 keV) could require up to approximately 4 mm of water equivalent material for positron annihilation. Thus many of the positrons do not annihilate inside the leaf, resulting in limited sensitivity for PET imaging. To address this problem we have developed a compact beta-positive, beta-minus particle imager (PhytoBeta imager) for 11CO2 leaf imaging. The detector is based on a Hamamatsu H8500 position sensitive photomultiplier tube optically coupled via optical grease to a 0.5 mm thick Eljen EJ-212 plastic scintillator. The detector is equipped with a flexible arm to allow its placement and orientation over or under the leaf to be studied while maintaining the leaf's original orientation. To test the utility of the system the detector was used to measure carbon translocation in a leaf of the spicebush (Lindera benzoin) under two transient light conditions. (paper)

  3. Biological effects of inhaled radionuclides

    International Nuclear Information System (INIS)

    This report focuses on various types of radionuclides that may be inhaled and deposited in the respiratory tract. One of the primary goals of this ICRP Task Group is to assess specifically the biological implications of inhaled plutonium. Because other transuranics are becoming more abundant, information on americium, curium and einsteinium is included. Data are also included from studies of polonium and of several beta-gamma emitting isotopes. The Task Group evaluated most of the data on the biological effects of inhaled radionuclides in experimental animals to identify the tissues at risk and to assess possible dose-response relationships. Few data from human cases of inhaled radionuclides are available for this assessment. The biological effects of nonradioactive air pollutants were also considered to provide the perspective that all air pollutants can have a deleterious effect on human life and to emphasize the possibility for combined or synergistic effects of nonradioactive and radioactive substances on the respiratory tract. (orig./HP)

  4. Biological effects of neutrons

    International Nuclear Information System (INIS)

    Although the occasion to be exposed to neutrons is rare in our life, except for nuclear accidents like in the critical accident at Tokai-mura in 1999, countermeasures against accident should be always prepared. In the Tokai-mura accident, residents received less than 21 mSv of neutrons and gamma rays. The cancer risks and fetal effects of low doses of neutrons were matters of concern among residents. The purpose of this program is to investigate the relative biological effectiveness (RBE) for leukemias, and thereby to assess risks of neutrons. Animal experiments are planed to obtain the following RBEs: (1) RBE for the induction of leukemias in mice and (2) RBE for effects on fetuses. Cyclotron fast neutrons (10 MeV) and electrostatic accelerator-derived neutrons (2 MeV) are used for exposure in this program. Furthermore, cytological and cytogenetic analyses will be performed. (author)

  5. Effects of indirect actions and oxygen on relative biological effectiveness. Estimate of DSB induction and conversion induced by gamma rays and helium ions

    International Nuclear Information System (INIS)

    Clustered DNA damage other than double-strand breaks (DSBs) can be detrimental to cells and can lead to mutagenesis or cell death. In addition to DSBs induced by ionizing radiation, misrepair of non-DSB clustered damage contributes extra DSBs converted from DNA misrepair via pathways for base excision repair and nucleotide excision repair. This study aimed to quantify the relative biological effectiveness (RBE) when DSB induction and conversion from non-DSB clustered damage misrepair were used as biological endpoints. The results showed that both linear energy transfer (LET) and indirect action had a strong impact on the yields for DSB induction and conversion. RBE values for DSB induction and maximum DSB conversion of helium ions (LET = 120 keV/μm) to 60Co gamma rays were 3.0 and 3.2, respectively. These RBE values increased to 5.8 and 5.6 in the absence of interference of indirect action initiated by addition of 2-M dimethylsulfoxide. DSB conversion was ∼1–4% of the total non-DSB damage due to gamma rays, which was lower than the 10% estimate by experimental measurement. Five to twenty percent of total non-DSB damage due to helium ions was converted into DSBs. Hence, it may be possible to increase the yields of DSBs in cancerous cells through DNA repair pathways, ultimately enhancing cell killing. (author)

  6. Competition of $\\beta$-delayed protons and $\\beta$-delayed $\\gamma$ rays in $^{56}$Zn and the exotic $\\beta$-delayed $\\gamma$-proton decay

    CERN Document Server

    Orrigo, S E A; Fujita, Y; Blank, B; Gelletly, W; Agramunt, J; Algora, A; Ascher, P; Bilgier, B; Cáceres, L; Cakirli, R B; Fujita, H; Ganioglu, E; Gerbaux, M; Giovinazzo, J; Grévy, S; Kamalou, O; Kozer, H C; Kucuk, L; Kurtukian-Nieto, T; Molina, F; Popescu, L; Rogers, A M; Susoy, G; Stodel, C; Suzuki, T; Tamii, A; Thomas, J C

    2016-01-01

    Remarkable results have been published recently on the $\\beta$ decay of $^{56}$Zn. In particular, the rare and exotic $\\beta$-delayed $\\gamma$-proton emission has been detected for the first time in the $fp$ shell. Here we focus the discussion on this exotic decay mode and on the observed competition between $\\beta$-delayed protons and $\\beta$-delayed $\\gamma$ rays from the Isobaric Analogue State.

  7. A biological effectiveness study on chromosomal aberrations induced by fission neutrons versus 60Co γ-rays in human peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Objective: Whole blood lymphocytes samples being exposed to neutrons of 18 MeV energy and 60Co γ-rays respectively, both good dose-response relationships and relative biological effectiveness (RBE) were derived. Methods: Heparinized whole blood samples were exposed to neutrons and 60Co γ-rays, respectively. Radiation doses were from 0.5 Gy to 3.0 Gy. Dose rate was 0.2 Gy/min. Unstable chromosomal aberrations dicentrics and centric rings (dic+r), the same as Micronuclei in binucleated cells, were scored. Relative biological effectiveness (RBE) values of dic+rand Micronucleus were derived. Results: Chromosomal aberrations (dic+r) and Micronucleus induced by either neutrons or 60Co γ-rays had a good dose-response relationship. RBE value of chromosomal aberrations, exposed neutrons at 0.5-3.0 Gy, ranged from 1.59 to 2.81, similarly, micronucleus from 1.23 to 2.14. Conclusion: linear-quadratic dose-response was found for the induction of dic+r and Micronucleus in human lymphocytes exposed in vitro to neutrons of 18 MeV energy. neutrons has higher biological effectiveness in low doses. (authors)

  8. Gamma ray irradiation for sludge solubilization and biological nitrogen removal

    International Nuclear Information System (INIS)

    This study was conducted to investigate the effects of gamma ray irradiation on the solubilization of waste sewage sludge. The recovery of an organic carbon source from sewage sludge by gamma ray irradiation was also studied. The gamma ray irradiation showed effective sludge solubilization efficiencies. Both soluble chemical oxygen demand (SCOD) and biochemical oxygen demand (BOD5) increased by gamma ray irradiation. The feasibility of the solubilized sludge carbon source for a biological nitrogen removal was also investigated. A modified continuous bioreactor (MLE process) for a denitrification was operated for 20 days by using synthetic wastewater. It can be concluded that the gamma ray irradiation was useful for the solubilization of sludge and the recovery of carbon source from the waste sewage sludge for biological nitrogen removal. - Research highlights: → This study was conducted to investigate the effects of gamma ray irradiation on the solubilization of waste sewagesludge. → The recovery of an organic carbon source from sewage sludge by gamma ray irradiation was also studied. → It can be concluded that the gamma ray irradiation was useful for the solubilization of sludge and the recovery of carbon source from the waste sewage sludge for biological nitrogen removal.

  9. On gamma-ray bursts and their biological effects :a case for an extrinsic trigger of the Cambrian explosion ?

    CERN Document Server

    Horváth, J E

    2003-01-01

    We discuss some the effects of local gamma-ray bursts on the earth's atmosphere. A rough calculation of the fraction of ozone destruction by catalytic $NO_{x}$ cycles is given, which in turn serves to argue how the large flux of gammas from these events would have indirectly provoked major extinction of living organisms. We give specific examples of these features, and tentatively identify the Cambrian explosion seen in the actual fossil record as an event caused by a GRB.

  10. Biological effects of high LET radiations

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masami [Nagasaki Univ. (Japan). Faculty of Pharmaceutical Sciences

    1997-03-01

    Biological effect of radiation is different by a kind of it greatly. Heavy ions were generally more effective in cell inactivation, chromosome aberration induction, mutation induction and neoplastic cell transformation induction than {gamma}-rays in SHE cells. (author)

  11. Comparison of the biological effectiveness of 45 MeV C-ions and γ-rays in inducing early and late effects in normal human primary fibroblasts

    Science.gov (United States)

    Fratini, E.; Balduzzi, M.; Antonelli, F.; Sorrentino, E.; Esposito, G.; Cuttone, G.; Romano, F.; Dini, V.; Simone, G.; Belli, M.; Campa, A.; Tabocchini, M. A.

    2013-07-01

    Investigation of the mechanisms underlying the biological effects induced by densely ionizing radiation has relevant implications in both radiation protection and therapy. In particular, the possible advantages of hadrontherapy with respect to conventional radiotherapy in terms of high conformal tumor treatment and sparing of healthy tissues are well known. Further improvements are limited by lack of radiobiological knowledge, particularly about the specific cellular response to the damage induced by particles of potential interest for tumor treatment. This study compares early and late effects induced in AG01522 normal human primary fibroblasts by γ-rays and C-ions having E ˜ 45 MeV/u at the cell entrance, corresponding to LET (in water) ˜ 49 keV/μm. Different end points have been investigated, namely: cell killing and lethal mutation, evaluated as early and delayed reproductive cell death, respectively; chromosome damage, as measured by micronuclei induction (MN); DNA damage, in terms of DSB induction and repair, as measured by the H2AX phosphorylation/dephosphorylation kinetics. Linear dose-response relationships were found for cell killing and induction of lethal mutations, with RBEs of about 1.3 and 1.6 respectively, indicating that the presence of genomic instability is greater in the progeny of C-ions irradiated cells. H2AX phosphorylation/dephosphorylation kinetics have shown a maximum foci number at 30 min after irradiation, higher for γ-rays than for C-ions. However, in the first 12 h the fraction of residual γ-H2AX foci was higher for C-ions irradiated cells, indicating a lower removal rate, possibly related to multiple/more complex damage along the particle track, with respect to the sparse lesions produced by γ-rays. MN induction, observed after 72 h from irradiation, was also greater for C-ions. Overall, these data indicate a more severe DNA damage induced by 45 MeV/u C-ions with respect to γ-rays, likely responsible of an increased cellular

  12. Comparison of the biological effectiveness of 45 MeV C-ions and {gamma}-rays in inducing early and late effects in normal human primary fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Fratini, E. [Centro studi e ricerche e museo storico della fisica E. Fermi, Roma (Italy); Balduzzi, M. [ENEA, Roma, Italy and INFN, Sezione Roma1-Gruppo Collegato Sanita, Roma (Italy); Antonelli, F.; Sorrentino, E.; Esposito, G. [Istituto Superiore di Sanita, Roma, Italy and INFN, Sezione Roma1-Gruppo Collegato Sanita, Roma (Italy); Cuttone, G.; Romano, F. [INFN-LNS, Catania (Italy); Dini, V.; Simone, G.; Campa, A.; Tabocchini, M. A. [stituto Superiore di Sanita, Roma, Italy and INFN, Sezione Roma1-Gruppo Collegato Sanita, Roma (Italy); Belli, M. [INFN, Sezione Roma1-Gruppo Collegato Sanita, Roma (Italy)

    2013-07-18

    Investigation of the mechanisms underlying the biological effects induced by densely ionizing radiation has relevant implications in both radiation protection and therapy. In particular, the possible advantages of hadrontherapy with respect to conventional radiotherapy in terms of high conformal tumor treatment and sparing of healthy tissues are well known. Further improvements are limited by lack of radiobiological knowledge, particularly about the specific cellular response to the damage induced by particles of potential interest for tumor treatment. This study compares early and late effects induced in AG01522 normal human primary fibroblasts by {gamma}-rays and C-ions having E {approx} 45 MeV/u at the cell entrance, corresponding to LET (in water) {approx} 49 keV/{mu}m. Different end points have been investigated, namely: cell killing and lethal mutation, evaluated as early and delayed reproductive cell death, respectively; chromosome damage, as measured by micronuclei induction (MN); DNA damage, in terms of DSB induction and repair, as measured by the H2AX phosphorylation/dephosphorylation kinetics. Linear dose-response relationships were found for cell killing and induction of lethal mutations, with RBEs of about 1.3 and 1.6 respectively, indicating that the presence of genomic instability is greater in the progeny of C-ions irradiated cells. H2AX phosphorylation/dephosphorylation kinetics have shown a maximum foci number at 30 min after irradiation, higher for {gamma}-rays than for C-ions. However, in the first 12 h the fraction of residual {gamma}-H2AX foci was higher for C-ions irradiated cells, indicating a lower removal rate, possibly related to multiple/more complex damage along the particle track, with respect to the sparse lesions produced by {gamma}-rays. MN induction, observed after 72 h from irradiation, was also greater for C-ions. Overall, these data indicate a more severe DNA damage induced by 45 MeV/u C-ions with respect to {gamma}-rays, likely

  13. Modeling the transmission of beta rays through thin foils in planar geometry.

    Science.gov (United States)

    Stanga, D; De Felice, P; Keightley, J; Capogni, M; Ionescu, E

    2016-01-01

    This paper is concerned with the modeling of the transmission of beta rays through thin foils in planar geometry based on the plane source concept, using Monte Carlo simulation of electron transport and least squares fitting. Applications of modeling results for calculating the efficiency of large-area beta sources, transmission coefficient of beta rays through thin foils and the beta detection efficiency of large-area detectors used in surface contamination measurements are also presented. PMID:26524407

  14. [beta]-Lactamases in the Biochemistry and Molecular Biology Laboratory

    Science.gov (United States)

    Amador, Paula; Prudencio, Cristina; Vieira, Monica; Ferraz, Ricardo; Fonte, Rosalia; Silva, Nuno; Coelho, Pedro; Fernandes, Ruben

    2009-01-01

    [beta]-lactamases are hydrolytic enzymes that inactivate the [beta]-lactam ring of antibiotics such as penicillins and cephalosporins. The major diversity of studies carried out until now have mainly focused on the characterization of [beta]-lactamases recovered among clinical isolates of Gram-positive staphylococci and Gram-negative…

  15. Differential Superiority of Heavy Charged-Particle Irradiation to X-Rays: Studies on Biological Effectiveness and Side Effect Mechanisms in Multicellular Tumor and Normal Tissue Models.

    Science.gov (United States)

    Walenta, Stefan; Mueller-Klieser, Wolfgang

    2016-01-01

    This review is focused on the radiobiology of carbon ions compared to X-rays using multicellular models of tumors and normal mucosa. The first part summarizes basic radiobiological effects, as observed in cancer cells. The second, more clinically oriented part of the review, deals with radiation-induced cell migration and mucositis. Multicellular spheroids from V79 hamster cells were irradiated with X-rays or carbon ions under ambient or restricted oxygen supply conditions. Reliable oxygen enhancement ratios could be derived to be 2.9, 2.8, and 1.4 for irradiation with photons, (12)C(+6) in the plateau region, and (12)C(+6) in the Bragg peak, respectively. Similarly, a relative biological effectiveness of 4.3 and 2.1 for ambient pO2 and hypoxia was obtained, respectively. The high effectiveness of carbon ions was reflected by an enhanced accumulation of cells in G2/M and a dose-dependent massive induction of apoptosis. These data clearly show that heavy charged particles are more efficient in sterilizing tumor cells than conventional irradiation even under hypoxic conditions. Clinically relevant doses (3 Gy) of X-rays induced an increase in migratory activity of U87 but not of LN229 or HCT116 tumor cells. Such an increase in cell motility following irradiation in situ could be the source of recurrence. In contrast, carbon ion treatment was associated with a dose-dependent decrease in migration with all cell lines and under all conditions investigated. The radiation-induced loss of cell motility was correlated, in most cases, with corresponding changes in β1 integrin expression. The photon-induced increase in cell migration was paralleled by an elevated phosphorylation status of the epidermal growth factor receptor and AKT-ERK1/2 pathway. Such a hyperphosphorylation did not occur during (12)C(+6) irradiation under all conditions registered. Comparing the gene toxicity of X-rays with that of particles using the γH2AX technique in organotypic cultures of the oral

  16. Differential Superiority of Heavy Charged-Particle Irradiation to X-Rays: Studies on Biological Effectiveness and Side Effect Mechanisms in Multicellular Tumor and Normal Tissue Models

    Science.gov (United States)

    Walenta, Stefan; Mueller-Klieser, Wolfgang

    2016-01-01

    This review is focused on the radiobiology of carbon ions compared to X-rays using multicellular models of tumors and normal mucosa. The first part summarizes basic radiobiological effects, as observed in cancer cells. The second, more clinically oriented part of the review, deals with radiation-induced cell migration and mucositis. Multicellular spheroids from V79 hamster cells were irradiated with X-rays or carbon ions under ambient or restricted oxygen supply conditions. Reliable oxygen enhancement ratios could be derived to be 2.9, 2.8, and 1.4 for irradiation with photons, 12C+6 in the plateau region, and 12C+6 in the Bragg peak, respectively. Similarly, a relative biological effectiveness of 4.3 and 2.1 for ambient pO2 and hypoxia was obtained, respectively. The high effectiveness of carbon ions was reflected by an enhanced accumulation of cells in G2/M and a dose-dependent massive induction of apoptosis. These data clearly show that heavy charged particles are more efficient in sterilizing tumor cells than conventional irradiation even under hypoxic conditions. Clinically relevant doses (3 Gy) of X-rays induced an increase in migratory activity of U87 but not of LN229 or HCT116 tumor cells. Such an increase in cell motility following irradiation in situ could be the source of recurrence. In contrast, carbon ion treatment was associated with a dose-dependent decrease in migration with all cell lines and under all conditions investigated. The radiation-induced loss of cell motility was correlated, in most cases, with corresponding changes in β1 integrin expression. The photon-induced increase in cell migration was paralleled by an elevated phosphorylation status of the epidermal growth factor receptor and AKT-ERK1/2 pathway. Such a hyperphosphorylation did not occur during 12C+6 irradiation under all conditions registered. Comparing the gene toxicity of X-rays with that of particles using the γH2AX technique in organotypic cultures of the oral mucosa, the

  17. Relative Biological Effectiveness (RBE) of fission neutrons and gamma rays at occupational exposure levels: Volume 2, Studies on the effects of 60 equal once-weekly exposures to fission neutrons and gamma rays on survival of mice

    International Nuclear Information System (INIS)

    A total of 6316 mice were exposed to 60 once-weekly doses of 0.85 MeV fission neutrons or 60Co gamma rays and observed until they died. An additional 1404 mice were entered into the experiment and followed for part of their lifetimes; a few of these mice were lost accidentally, but most were removed for genetic testing. The mean aftersurvival (MAS) times showed dose-response curves for both neutron and gamma-ray exposures to be linear over all doses except the highest neutron dose. The relative biological effectiveness (RBE) value for neutrons, calculated as the ratio of the linear slopes of the dose-response curves for MAS times, was about 20 for both males and females. Essentially the same value was obtained by other analyses of the data. This RBE value of 20 is specific for deaths from all causes after 60 once-weekly exposures to 0.85 MeV fission neutrons, with once-weekly 60Co gamma-ray exposures as the reference radiation. The value for the RBE will probably be different for some, but not all, of the other end points (i.e., specific causes of death, especially tumors). 21 refs., 6 figs., 6 tabs

  18. X-ray-induced photo-chemistry and X-ray absorption spectroscopy of biological samples

    OpenAIRE

    George, Graham N.; Pickering, Ingrid J.; Pushie, M. Jake; Nienaber, Kurt; Hackett, Mark J.; Ascone, Isabella; Hedman, Britt; Hodgson, Keith O.; Aitken, Jade B.; Levina, Aviva; Glover, Christopher; Lay, Peter A.

    2012-01-01

    X-ray-induced photo-chemistry of metal sites within biological molecules is a concern for X-ray absorption spectroscopy, X-ray crystallography and other techniques in which samples are illuminated with X-rays. The effects of X-ray-induced photo-chemistry are reviewed and the methods used to mitigate these in X-ray absorption spectroscopy are outlined.

  19. Effects of beta/gamma radiation on nuclear waste glasses

    Energy Technology Data Exchange (ETDEWEB)

    Weber, W.J. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-07-01

    A key challenge in the disposal of high-level nuclear waste (HLW) in glass waste forms is the development of models of long-term performance based on sound scientific understanding of relevant phenomena. Beta decay of fission products is one source of radiation that can impact the performance of HLW glasses through the interactions of the emitted {beta}-particles and g-rays with the atoms in the glass by ionization processes. Fused silica, alkali silicate glasses, alkali borosilicate glasses, and nuclear waste glasses are all susceptible to radiation effects from ionization. In simple glasses, defects (e.g., non-bridging oxygen and interstitial molecular oxygen) are observed experimentally. In more complex glasses, including nuclear waste glasses, similar defects are expected, and changes in microstructure, such as the formation of bubbles, have been reported. The current state of knowledge regarding the effects of {beta}/{gamma} radiation on the properties and microstructure of nuclear waste glasses are reviewed. (author)

  20. Quality control of X-ray irradiator by biological markers

    International Nuclear Information System (INIS)

    The exposure of animals or cultured cells to radiation is the essential and common step in experimental researches to elucidate biological effects of radiation. When an X-ray generator is used as a radiation source, physical parameters including dose, dose rate, and the energy spectrum of X-ray play crucial roles in biological outcome. Therefore, those parameters are the important points to be checked in quality control and to be carefully considered in advance to the irradiation to obtain the accurate and reproductive results. Here we measured radiation dose emitted from the X-ray irradiator for research purposes by using clonogenic survival of cultured mammalian cells as a biological marker in parallel with physical dosimetry. The results drawn from both methods exhibited good consistency in the dose distribution on the irradiation stage. Furthermore, the close relationship was observed between cell survival and the photon energy spectrum by using different filter components. These results suggest that biological dosimetry is applicable to quality control of X-ray irradiator in adjunct to physical dosimetry and that it possibly helps better understanding of the optimal irradiating condition by X-ray users in life-science field. (author)

  1. Effects of beta radiation from organically bound tritium on cultured mouse embryonic mid brain cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bing [Univ. of Tokyo (Japan)]|[Toho Univ. School of Medicine, Tokyo (Japan); Watanabe, Keiko; Yamada, Takeshi [Toho Univ. School of Medicine, Tokyo (Japan); Shima, Akihiro [Univ. of Tokyo (Japan)

    1996-12-01

    Effects of beta radiation from four kinds of organically bound tritium compounds were investigated on cultured mouse embryonic mid brain cells, isolated form 11-d-old mouse embryos. The MBC showed a critical time when they were more radiosensitive. Although dose-dependent inhibition was found for both cellular proliferation and differentiation. the differential was more sensitive to radiation than proliferation when compared at ID50, the inhibitory dose that reduced assessment value by 50% of the control. Dose-dependent decrease of DNA and protein contents were also observed. The relative biological effectiveness values, ranging from 4.6 to 8.7, of beta ray from organically bound tritium compounds were obtained when compared with x irradiation at their ID50s on the inhibition of cell proliferation and differentiation, and on the decrease of DNA and protein contents of the cultures. Th mixed exposure to x ray and one kind of organically bound tritium compound or to any two kinds of organically bound tritium compound resulted in a more efficiently inhibitory effect on differentiation than the exposure to x ray or to any one kind of organically bound tritium compound d alone, especially when methyl-{sup 3}H-thymidine was used. Doses as low as 0.05 Gy (5 cGy) from a mixed exposure resulted in detectable inhibitory effects. 21 refs., 4 figs., 1 tab.

  2. Effects of beta radiation from organically bound tritium on cultured mouse embryonic mid brain cells

    International Nuclear Information System (INIS)

    Effects of beta radiation from four kinds of organically bound tritium compounds were investigated on cultured mouse embryonic mid brain cells, isolated form 11-d-old mouse embryos. The MBC showed a critical time when they were more radiosensitive. Although dose-dependent inhibition was found for both cellular proliferation and differentiation. the differential was more sensitive to radiation than proliferation when compared at ID50, the inhibitory dose that reduced assessment value by 50% of the control. Dose-dependent decrease of DNA and protein contents were also observed. The relative biological effectiveness values, ranging from 4.6 to 8.7, of beta ray from organically bound tritium compounds were obtained when compared with x irradiation at their ID50s on the inhibition of cell proliferation and differentiation, and on the decrease of DNA and protein contents of the cultures. Th mixed exposure to x ray and one kind of organically bound tritium compound or to any two kinds of organically bound tritium compound resulted in a more efficiently inhibitory effect on differentiation than the exposure to x ray or to any one kind of organically bound tritium compound d alone, especially when methyl-3H-thymidine was used. Doses as low as 0.05 Gy (5 cGy) from a mixed exposure resulted in detectable inhibitory effects. 21 refs., 4 figs., 1 tab

  3. SU-E-T-26: A Study On the Influence of Photonuclear Reactions On the Biological Effectiveness of Therapeutic High Energy X-Ray Beam

    Energy Technology Data Exchange (ETDEWEB)

    Wakita, A [Tokyo Institute of Technology, Yokohama-shi, Kanagawa (Japan); National Cancer Center Hospital, Chuo-ku, Tokyo (Japan); Matsufuji, N [Tokyo Institute of Technology, Yokohama-shi, Kanagawa (Japan); National Institute of Radiological Sciences, Chiba-shi, Chiba (Japan); Kohno, T [Tokyo Institute of Technology, Yokohama-shi, Kanagawa (Japan); Kodaira, S [National Institute of Radiological Sciences, Chiba-shi, Chiba (Japan); Yokoyama, K; Suzuki, Y; Itami, J [National Cancer Center Hospital, Chuo-ku, Tokyo (Japan)

    2014-06-01

    Purpose: Photons from a modern high-energy therapeutic linear accelerator used in X-ray radiotherapy causes photonuclear reactions in an accelerator or patient's body. The aim of this study is to evaluate the biological effectiveness including these particles by Microdosimetric Kinetic Model (MKM) based on microdosimetry. Methods: A linear accelerator operating at 15 MV was used. CR-39 was used to obtain LET spectra of secondary ions selectively, as CR-39 is regarded insensitive to photons. CR-39 was put on the central axis of the X-ray beam at depths of 0, 5 and 10 cm in plastic phantom at a source to detector distance of 100 cm. Pits formed by the traversal of ions were etched then analyzed to obtain restricted LET distribution. Frequency-mean and dose-mean lineal energy was evaluated from the relationship between the restricted LET and the lineal energy required to evaluate the biological effectiveness by MKM. The relationship was calculated by Monte Carlo simulations with GEANT4. Results: Restricted LET distributions of secondary particles showed broad distributions that decreases exponentially with increasing LET. Frequency-mean and dose-mean lineal energy were determined uniquely within the scope of the energies of secondary particles generated from photons of 15 MeV. The frequency-mean lineal energies at the depth of 0, 5 and 10 cm were 15.1, 16.0 and 19.7 keV/μm respectively, and the dose-mean lineal energies were 18.6, 20.5 and 19.6 keV/μm, respectively. RBE of secondary particles for HSG cell evaluated by MKM was about 2.0 at all depths, and RBE of all particles including photons was evaluated 1.0. Conclusion: We investigated the biological effectiveness of secondary particles by photonuclear reactions. The method to evaluate RBE by MKM was established with measurements and simulations. However, the influence of these secondary ions on RBE was found negligible in the entire biological effectiveness of the high-energy X-ray. This study has been

  4. Beta-ray treatment of malignant epithelial tumors of the conjunctiva

    International Nuclear Information System (INIS)

    Fifteen patients with malignant epithelial tumors of the conjunctiva were treated with beta-ray ocular applicators filled with radioactive strontium and yttrium (90Sr/90Y). Histologic examination confirmed the diagnosis. There were ten squamous cell carcinomas, four carcinomas in situ, and one case of epidermidalization. In one patient, who may have received an insufficient dose, recurrence led to enucleation. Radiogenic complications--secondary glaucoma and corneal degeneration--caused visual loss in two other patients. All of the other tumors disappeared completely without seriously affecting the eyes. Beta-ray irradiation with 90Sr/90Y applicators was effective if a sufficient dose (15,000 to 18,000 rads) was applied to the tumor surface and if the height of the tumor did not exceed 5 mm

  5. The biological activities of (1,3)-(1,6)-{beta}-d-glucan and porous electrospun PLGA membranes containing {beta}-glucan in human dermal fibroblasts and adipose tissue-derived stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Yeon I; Park, Bong Joo; Kim, Hye-Lee; Lee, Mi Hee; Kim, Jungsung; Park, Jong-Chul [Department of Medical Engineering, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Yang, Young-Il [Department of Pathology, School of Medicine, Paik Institute for Clinical Research, Inje University, 633-165 Gae-dong, Busan-jin-gu, Busan 614-735 (Korea, Republic of); Kim, Jung Koo [Department of Biomedical Engineering, College of Biomedical Science and Engineering, Inje University, Kimhae 621-749 (Korea, Republic of); Tsubaki, Kazufumi [R and D division, Asahi Denka Co. Ltd, 7-2-35 Higashi-ogu, Arakawa-ku, Tokyo 116-8554 (Japan); Han, Dong-Wook, E-mail: parkjc@yuhs.a [Department of Nanomedical Engineering, College of Nanoscience and Nanotechnology, Pusan National University, geumjeong-gu, Busan 609-735 (Korea, Republic of)

    2010-08-01

    In this study, we investigated the possible roles of (1,3)-(1,6)-{beta}-d-glucan ({beta}-glucan) and porous electrospun poly-lactide-co-glycolide (PLGA) membranes containing {beta}-glucan for skin wound healing, especially their effect on adult human dermal fibroblast (aHDF) and adipose tissue-derived stem cell (ADSC) activation, proliferation, migration, collagen gel contraction and biological safety tests of the prepared membrane. This study demonstrated that {beta}-glucan and porous PLGA membranes containing {beta}-glucan have enhanced the cellular responses, proliferation and migration, of aHDFs and ADSCs and the result of a collagen gel contraction assay also revealed that collagen gels contract strongly after 4 h post-gelation incubation with {beta}-glucan. Furthermore, we confirmed that porous PLGA membranes containing {beta}-glucan are biologically safe for wound healing study. These results indicate that the porous PLGA membranes containing {beta}-glucan interacted favorably with the membrane and the topical administration of {beta}-glucan was useful in promoting wound healing. Therefore, our study suggests that {beta}-glucan and porous PLGA membranes containing {beta}-glucan may be useful as a material for enhancing wound healing.

  6. The origins of radiotherapy: Discovery of biological effects of X-rays by Freund in 1897, Kienböck’s crucial experiments in 1900, and still it is the dose

    International Nuclear Information System (INIS)

    The discovery of X-rays by Wilhelm Conrad Röntgen (1845–1923) was triggered by pursuing an anomalous phenomenon: arousal of fluorescence at a distance from tubes in which cathode rays were elicited, a phenomenon which suggested the existence of a new kind of ray other than cathode rays. The discovery of biological effects of these X-rays by Leopold Freund (1868–1943) was triggered by pursuit of the purportedly useless phenomenon of epilation and dermatitis ensuing from X-ray-diagnostic experiments that others had reported. The crucial experiments performed by Robert Kienböck (1871–1953) entailed the proof that X-ray-dose, not electric phenomena, was the active agent of biological effects ensuing when illuminating the skin using Röntgen tubes. For both the discovery of X-rays and the discovery of their biological effectiveness, priority did not matter, but understanding the physical and medico-biological significance of phenomena that others had ignored as a nuisance. Present discussions about the clinical relevance of improving the dose distribution including protons and other charged particles resemble those around 1900 to a certain degree

  7. Effects of 60Co γ-rays radiation on biological characters of Platanus acerifolia Willd. weed and seedlings

    International Nuclear Information System (INIS)

    The dry seeds of Platanus acerifolia Willd. were irradiated by different doses of 60Co γ-rays, and the effect of the radiation on M1 were investigated. Results showed that the seed germination rate, emerged seedling rate and survival seedling rate of Platanus aceriflia Willd. Decreased with dose increase at the dose of 50-400 Gy, as well as the plant height, fresh weight and length of root. The radiation inhibited the seeding growth significantly. Compared with CK, the true leaf emerging time of samples irradiated at 50-250 Gy was late for 2, 5, 9 and 14d, respectively. But the young seedlings of samples treated at 300-400 Gy were severely twisted and abnormal, and gradually died after 15d. Based on the data of seeding rate and root growth, it is concluded that the semi-lethal radiation dose of Platanus acerifolia Willd. dry seed was 50 Gy, and the suitable dose range for radiation breeding was 50 to 250 Gy. (authors)

  8. Differential superiority of heavy charged-particle irradiation to x-rays: Studies on biological effectivenes and side effect mechanisms in multicellular tumor and normal tissue models

    Directory of Open Access Journals (Sweden)

    Stefan eWalenta

    2016-02-01

    Full Text Available This review is focused on the radiobiology of carbon ions compared to x-rays using multicellular models of tumors and normal mucosa. The first part summarizes basic radiobiological effects, as observed in cancer cells. The second, more clinically oriented part of the review deals with radiation-induced cell migration and mucositis.Multicellular spheroids (MCS from V79 hamster cells were irradiated with x-rays or carbon ions under ambient or restricted oxygen supply conditions. Oxygen enhancement ratios (OER were 2.9, 2.8, and 1.4 for irradiation with photons, 12C+6 in the plateau region, and 12C+6 in the Bragg peak, respectively. A relative biological effectiveness (RBE of 4.3 and 2.1 for ambient pO2 and hypoxia was obtained, respectively. The high effectiveness of carbon ions was reflected by an enhanced accumulation of cells in G2/M, and a dose-dependent massive induction of apoptosis. Clinically relevant doses (3 Gy of x-rays induced an increase in migratory activity of U87 but not of LN229 or HCT116 tumor cells. Such an increase in cell motility following irradiation in situ could be the source of recurrence. In contrast, carbon ion treatment was associated with a dose-dependent decrease in migration with all cell lines and under all conditions investigated. The radiation-induced loss of cell motility was correlated, in most cases, with corresponding changes in 1 integrin expression. Unlike with particles, the photon-induced increase in cell migration was paralleled by an elevated phosphorylation status of the epidermal growth factor receptor (EGFR and AKT-ERK1/2 pathway. Comparing the gene toxicity of x-rays with that of particles using the gamma-H2AX technique in organotypic cultures of the oral mucosa, the superior effectiveness of heavy ions was confirmed by a two-fold higher number of foci per nucleus. Pro-inflammatory signs, however, were similar for both treatment modalities, e. g., the activation of NFkappaB, and the release of IL

  9. Relative Biologic Effectiveness (RBE) of 50 kV X-rays Measured in a Phantom for Intraoperative Tumor-Bed Irradiation

    International Nuclear Information System (INIS)

    Purpose: Intraoperative radiation therapy (IORT) with low-energy x-rays is used to treat the tumor bed during breast-conserving surgery. The purpose was to determine the relative biologic effectiveness (RBE) of 50-kV x-rays for inactivation of cells irradiated in a tumor-bed phantom. Methods and Materials: The RBE was determined for clonogenic inactivation of human tumor and normal cells (MCF7, human umbilical vein endothelial cells, normal skin fibroblasts), and hamster V79 cells. The 50-kV x-rays from the Intrabeam machine (Carl Zeiss Surgical) with a spherical 4-cm applicator were used. Cells were irradiated in a water-equivalent phantom at defined distances (8.1-22.9 mm) from the applicator surface. The 50-kV x-rays from a surface therapy machine (Dermopan, Siemens) were included for comparison; 6-MV x-rays were used as reference radiation. Results: At 8.1-mm depth in the phantom (dose rate 15.1 Gy/h), mean RBE values of 50-kV x-rays from Intrabeam were 1.26 to 1.42 for the 4 cell types at doses yielding surviving fractions in the range of 0.01 to 0.5. Confidence intervals were in the range of 1.2 and 1.5. Similar RBE values were found for 50-kV x-rays from Dermopan for V79 (1.30, CI 1.25-1.36, P=.74) and GS4 (1.42, CI 1.30-1.54, P=.67). No significant dependence of RBE on dose was found for Intrabeam, but RBE decreased at a larger distance (12.7 mm; 9.8 Gy/h). Conclusions: An increased clinically relevant RBE was found for cell irradiation with Intrabeam at depths in the tumor bed targeted by IORT. The reduced RBE values at larger distances may be related to increased repair of sublethal damage during protracted irradiation or to hardening of the photon beam energy

  10. Relative Biologic Effectiveness (RBE) of 50 kV X-rays Measured in a Phantom for Intraoperative Tumor-Bed Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qi; Schneider, Frank; Ma, Lin; Wenz, Frederik [Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim (Germany); Herskind, Carsten, E-mail: carsten.herskind@medma.uni-heidelberg.de [Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim (Germany)

    2013-03-15

    Purpose: Intraoperative radiation therapy (IORT) with low-energy x-rays is used to treat the tumor bed during breast-conserving surgery. The purpose was to determine the relative biologic effectiveness (RBE) of 50-kV x-rays for inactivation of cells irradiated in a tumor-bed phantom. Methods and Materials: The RBE was determined for clonogenic inactivation of human tumor and normal cells (MCF7, human umbilical vein endothelial cells, normal skin fibroblasts), and hamster V79 cells. The 50-kV x-rays from the Intrabeam machine (Carl Zeiss Surgical) with a spherical 4-cm applicator were used. Cells were irradiated in a water-equivalent phantom at defined distances (8.1-22.9 mm) from the applicator surface. The 50-kV x-rays from a surface therapy machine (Dermopan, Siemens) were included for comparison; 6-MV x-rays were used as reference radiation. Results: At 8.1-mm depth in the phantom (dose rate 15.1 Gy/h), mean RBE values of 50-kV x-rays from Intrabeam were 1.26 to 1.42 for the 4 cell types at doses yielding surviving fractions in the range of 0.01 to 0.5. Confidence intervals were in the range of 1.2 and 1.5. Similar RBE values were found for 50-kV x-rays from Dermopan for V79 (1.30, CI 1.25-1.36, P=.74) and GS4 (1.42, CI 1.30-1.54, P=.67). No significant dependence of RBE on dose was found for Intrabeam, but RBE decreased at a larger distance (12.7 mm; 9.8 Gy/h). Conclusions: An increased clinically relevant RBE was found for cell irradiation with Intrabeam at depths in the tumor bed targeted by IORT. The reduced RBE values at larger distances may be related to increased repair of sublethal damage during protracted irradiation or to hardening of the photon beam energy.

  11. Biological Effects of Ionizing Radiation

    Science.gov (United States)

    Ingram, M.; Mason, W. B.; Whipple, G. H.; Howland, J. W.

    1952-04-07

    This report presents a review of present knowledge and concepts of the biological effects of ionizing radiations. Among the topics discussed are the physical and chemical effects of ionizing radiation on biological systems, morphological and physiological changes observed in biological systems subjected to ionizing radiations, physiological changes in the intact animal, latent changes following exposure of biological systems to ionizing radiations, factors influencing the biological response to ionizing radiation, relative effects of various ionizing radiations, and biological dosimetry.

  12. Studies on the effect of grain size on the response of a CaS04:Dy teflon disc dosemeter for monoenergetic electrons and beta rays

    International Nuclear Information System (INIS)

    The attenuation factor d increases slowly with energy as well as with grain size. The absorbed dose ratio increases with energy. At lower energies it varies with cavity size but at higher energies the variation tends to become negligible when Burlin's expression is used and where the production of secondary electrons is not considered. The author shows that the absorbed dose calculated using Almond's expression varied negligibly with cavity size and hence the grain size does not affect the response of CaS04 for electrons or beta particles. (UK)

  13. Beta-ray dose assessment from skin contamination using a point kernel method

    International Nuclear Information System (INIS)

    In this study, a point kernel method to calculate beta-ray dose rate from skin contamination was introduced. The beta-ray doses rates were computed by performing numerical integration of the radial dose distribution around an isotropic point source of monoenergetic electrons called as point kernel. In this study, in-house code, based on MATLAB version 7.0.4 was developed to perform a numerical integration. The code generated dose distributions for beta-ray emitters from interpolated point kernel, and beta-ray dose rates from skin contamination were calculated by numerical integration. Generated dose distributions for selected beta-ray emitters agreed with those calculated by Cross et al within 20%, except at a longer distance where there are differences up to more than 100%. For a point source, calculated beta-ray doses were agreed well with those derived from Monte Carlo simulation. For a disk source, the differences were up to 17% at a deep region. Point kernel method underestimated beta-ray doses than Monte Carlo simulation. The code will be improved to deal with a three-dimensional source, shielding by cover material, air gap and contribution of photon to skin dose. For the sake of user's convenience, the code will be equipped with graphic user interface. (author)

  14. Precise Proportional Counting of Beta-Ray Emitting Liquid

    International Nuclear Information System (INIS)

    Samples of beta-ray emitting liquids are often assayed using an all-glass G-M counter where the liquid is placed between an outer cylinder and the counting tube (Veall-type counter). Besides the well-known disadvantages of G-M tubes, these jacketed counters are difficult to handle, fragile and apt to change their counting characteristics. A methane-flow proportional counter was developed in our Laboratory specifically for β-emitting liquid samples. The liquid is placed in a plastic cylinder with a bottom of aluminized mylar foil (1 mg/cm2). This vessel is screwed into the top of a circular proportional counter. In case of contamination, the vessel can be replaced. When the bottom foil is exchanged, a calibration curve, giving the efficiency as a function of the measured weight per unit area, may be used to obtain a new value for the efficiency. This counter was used successfully for the assay of 32P, 204Tl and 35S solutions giving results reproducible to ±0.2%. Compared with the jacketed counter, the counting efficiency of our counter is higher for low-energy β-emitters although somewhat lower for high-energy β-emitters. (author)

  15. Relative biological effectiveness (RBE) of fission neutrons and gamma rays at occupational exposure levels: Volume 1, Studies on the genetic effects in mice of 60 equal once-weekly exposures to fission neutrons and gamma rays

    International Nuclear Information System (INIS)

    The relative biological effectiveness (RBE) values for low doses of fission neutrons compared to 60Co gamma rays were determined with four separate assessments of genetic damage induced in young hybrid male mice. Both radiations were delivered at low dose levels over about one-half the adult lifetime as 60 once-weekly exposures. Genetic damage assessed included both transient and residual injury. The latter is more critical, as residual genetic injury can be transmitted to subsequent generations long after the radiation exposures have ceased. Assays were performed periodically during the 60-week exposure period and at 10 or more weeks after the irradiations had terminated. RBE values, with few exceptions, ranged between 5 and 15 for transient injury and between 25 and 50 for different types of residual genetic injury. The most important form of residual genetic damage in this study was the balanced reciprocal chromosome translocation. These translocations continue to be transmitted throughout reproductive life and can lead to reduced fertility and increased prenatal mortality. The best estimate of the RBE value for translocations was 45 +- 10. Implications and recommendations with regard to the neutron quality factor will be presented conjointly with the findings from the data obtained in this same project on life shortening and on the risks of incidence or death from neoplastic disease. 64 refs., 23 tabs

  16. The effect of physical therapy on beta-endorphin levels.

    Science.gov (United States)

    Bender, Tamás; Nagy, György; Barna, István; Tefner, Ildikó; Kádas, Eva; Géher, Pál

    2007-07-01

    Beta-endorphin (betaE) is an important reliever of pain. Various stressors and certain modalities of physiotherapy are potent inducers of the release of endogenous betaE to the blood stream. Most forms of exercise also increase blood betaE level, especially when exercise intensity involves reaching the anaerobic threshold and is associated with the elevation of serum lactate level. Age, gender, and mental activity during exercise also may influence betaE levels. Publications on the potential stimulating effect of manual therapy and massage on betaE release are controversial. Sauna, mud bath, and thermal water increase betaE levels through conveying heat to the tissues. The majority of the techniques for electrical stimulation have a similar effect, which is exerted both centrally and--to a lesser extent--peripherally. However, the parameters of electrotherapy have not yet been standardised. The efficacy of analgesia and the improvement of general well-being do not necessarily correlate with betaE level. Although in addition to blood, increased brain and cerebrospinal fluid betaE levels are also associated with pain, the majority of studies have concerned blood betaE levels. In general, various modalities of physical therapy might influence endorphin levels in the serum or in the cerebrospinal fluid--this is usually manifested by elevation with potential mitigation of pain. However, a causal relationship between the elevation of blood, cerebrospinal fluid or brain betaE levels and the onset of the analgesic action cannot be demonstrated with certainty. PMID:17483960

  17. Quantum Effects in Biology

    Science.gov (United States)

    Mohseni, Masoud; Omar, Yasser; Engel, Gregory S.; Plenio, Martin B.

    2014-08-01

    List of contributors; Preface; Part I. Introduction: 1. Quantum biology: introduction Graham R. Fleming and Gregory D. Scholes; 2. Open quantum system approaches to biological systems Alireza Shabani, Masoud Mohseni, Seogjoo Jang, Akihito Ishizaki, Martin Plenio, Patrick Rebentrost, Alàn Aspuru-Guzik, Jianshu Cao, Seth Lloyd and Robert Silbey; 3. Generalized Förster resonance energy transfer Seogjoo Jang, Hoda Hossein-Nejad and Gregory D. Scholes; 4. Multidimensional electronic spectroscopy Tomáš Mančal; Part II. Quantum Effects in Bacterial Photosynthetic Energy Transfer: 5. Structure, function, and quantum dynamics of pigment protein complexes Ioan Kosztin and Klaus Schulten; 6. Direct observation of quantum coherence Gregory S. Engel; 7. Environment-assisted quantum transport Masoud Mohseni, Alàn Aspuru-Guzik, Patrick Rebentrost, Alireza Shabani, Seth Lloyd, Susana F. Huelga and Martin B. Plenio; Part III. Quantum Effects in Higher Organisms and Applications: 8. Excitation energy transfer in higher plants Elisabet Romero, Vladimir I. Novoderezhkin and Rienk van Grondelle; 9. Electron transfer in proteins Spiros S. Skourtis; 10. A chemical compass for bird navigation Ilia A. Solov'yov, Thorsten Ritz, Klaus Schulten and Peter J. Hore; 11. Quantum biology of retinal Klaus Schulten and Shigehiko Hayashi; 12. Quantum vibrational effects on sense of smell A. M. Stoneham, L. Turin, J. C. Brookes and A. P. Horsfield; 13. A perspective on possible manifestations of entanglement in biological systems Hans J. Briegel and Sandu Popescu; 14. Design and applications of bio-inspired quantum materials Mohan Sarovar, Dörthe M. Eisele and K. Birgitta Whaley; 15. Coherent excitons in carbon nanotubes Leonas Valkunas and Darius Abramavicius; Glossary; References; Index.

  18. Estimate of beta and gamma contamination in vegetable and animal biologic samples using GM detectors

    International Nuclear Information System (INIS)

    The paper presents the use of a large area Geiger-Mueller Detector (GMD) with aluminium window of 50 mm thickness (3,4 mg/cm2) in a measuring chain in order to estimate the beta and gamma contamination of biologic samples. The technical data for GMD are: - window area for gamma radiation: 300 cm2; - grid transmission: 80%; - operating voltage: 1100 - 1300 V; - minimum detectable beta energy: 125 keV; - dead time: 250 ms; - background (shielded with 100 mm Pb + 1 mm Cu): 6 pulses/s; - service life: 5 x 108 counts. Using this GMD together with a set of large area beta standard sources and a set of point gamma sources we could estimate beta and gamma contamination in the energy range 125 keV - 2.5 MeV for biologic samples. (authors)

  19. Biological radiation effects

    International Nuclear Information System (INIS)

    The book covers all aspects of biological radiation effects and provides the fundamental basis for understanding the necessity of radiation protection as well as applications in radiotherapy. The physical basis is dealt with in some detail, and the effects at the subcellular and the cellular level are thoroughly discussed, taking into account modern developments and techniques. The effects on the human organism are reviewed, both from the point of view of applications in medicine as well as with regard to radiation hazards (teratogenic, gonadal and carcinogenic effects). It can be used by graduate students as an introduction and as a source book for all who want to become acquainted with this important field. It is an extended version of the original German book containing updated information and new material. (orig.) With 273 figs

  20. Neutron relative biological effectiveness for solid cancer incidence in the Japanese A-bomb survivors: an analysis considering the degree of independent effects from γ-ray and neutron absorbed doses with hierarchical partitioning.

    Science.gov (United States)

    Walsh, Linda

    2013-03-01

    It has generally been assumed that the neutron and γ-ray absorbed doses in the data from the life span study (LSS) of the Japanese A-bomb survivors are too highly correlated for an independent separation of the all solid cancer risks due to neutrons and due to γ-rays. However, with the release of the most recent data for all solid cancer incidence and the increased statistical power over previous datasets, it is instructive to consider alternatives to the usual approaches. Simple excess relative risk (ERR) models for radiation-induced solid cancer incidence fitted to the LSS epidemiological data have been applied with neutron and γ-ray absorbed doses as separate explanatory covariables. A simple evaluation of the degree of independent effects from γ-ray and neutron absorbed doses on the all solid cancer risk with the hierarchical partitioning (HP) technique is presented here. The degree of multi-collinearity between the γ-ray and neutron absorbed doses has also been considered. The results show that, whereas the partial correlation between the neutron and γ-ray colon absorbed doses may be considered to be high at 0.74, this value is just below the level beyond which remedial action, such as adding the doses together, is usually recommended. The resulting variance inflation factor is 2.2. Applying HP indicates that just under half of the drop in deviance resulting from adding the γ-ray and neutron absorbed doses to the baseline risk model comes from the joint effects of the neutrons and γ-rays-leaving a substantial proportion of this deviance drop accounted for by individual effects of the neutrons and γ-rays. The average ERR/Gy γ-ray absorbed dose and the ERR/Gy neutron absorbed dose that have been obtained here directly for the first time, agree well with previous indirect estimates. The average relative biological effectiveness (RBE) of neutrons relative to γ-rays, calculated directly from fit parameters to the all solid cancer ERR model with both

  1. The effect of pre-sowing irradiation of seeds with γ-rays on the biology and crop of cucumbers

    International Nuclear Information System (INIS)

    The effect of pre-sowing irradiation of dry cucumber seeds with doses in the range of 500 to 2000 :r has been studied. A 15.5 to 18.6 per cent increase in the crop of cucumbers has been observed, which is perhaps due to the increased ratio of male and female flower and to the augmented number of cucumbers and of dry sudstance quantity in them

  2. Establishment of Korea-Russia bilateral research collaboration for studies on biological effects of cosmic ray and space radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Juwoon; Kim, Dongho; Choi, Jongil; Song, Beomseok; Kim, Jaekyung; Kang, Oilhyun; Lee, Yoonjong; Kim, Jinhong; Jo, Minho

    2011-04-15

    {Omicron} KAERI-IBMP joint workshop on countermeasure and application researches to space environments - Sharing of state-of-the-art researches on space radiobiology using bio-satellites (BION-M1, Photon-soil) and ISS module (Bio-risk) was conducted - Sharing and discussion of state-of-the-art researches on dosimetry of space radiation and its affect on organisms were conducted. {Omicron} Making a contract on KAERI-IBMP Joint Research using Bio-risk module - Contract on KAERI-IBMP Joint Research to evaluate effect of space environment (microgravity and space radiation) on fermentative fungi (Aspergillus oryzae), Algae (Nostoc sp.), and plant seeds (rice, Arabidopsis thaliana, Brachypodium distachyon) was made in November, 2010. {Omicron} Discussion on new Joint Researches on evaluation of space radiation on organisms - Final step on Bion-M projects in terms of evaluation of physiological changes of lactic acid bacteria consumed by Mouse - Discussing new joint research on evaluation of physiological changes of primate by space radiation {Omicron} Establishment and management of the practical working group to invite a branch office of the IBMP in Korea - The system and the working group to implement cooperating researches between KAERI-IBMP on space radiation were established.

  3. Development of continuous monitor for multiple beta-ray nuclides in liquid radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Uk Won; Seon, G. I.; Kong, G. N.; Chin, H.; Park, J. H.; Yuk, I. S.; Han, W. Y. [Korea Astronomy and Space Science Institute, Taejon (Korea, Republic of)

    2001-03-15

    Continuous monitor system of multiple beta-ray nuclides was designed conceptually while keeping the optimization and the automation in mind. The conincidence MCA was designed to maintain, repair and upgrade with ease. DSP was adopted to realize hardware function using software and to miniaturize the coincidence Multi Channel Analyzer (MCA). The MCA system showed 99% background rejection rate, and was applied well to gamma-ray system using {sup 60}C0. An algorithm using least square method was developed for simultaneous radioassay of multiple beta-ray nuclides. The algorithm was tested using the simulation and was applied to experimental data. The results show that the algorithm is suitable to continous monitor system of multiple beta-ray nuclides.

  4. Graphite mixed magnesium borate TL dosemeters for beta ray dosimetry

    DEFF Research Database (Denmark)

    Prokic, M; Christensen, Poul

    1984-01-01

    Sintered MgB4O7:Dy dosemeters with graphite contents from 1 to 10% were investigated for application for personnel dosimetry. Data are given on dose response, dose threshold, reproducibility, beta energy response and fading. Furthermore, results from practical field experiments are presented...

  5. Biological effects of synchrotron radiation on crops

    Institute of Scientific and Technical Information of China (English)

    唐掌雄; 董保中; 等

    1996-01-01

    The sensitivity of germinating seeds of barley,winter wheat and spring one to synchrotron ultraviolet radiation is barley>winter wheat and spring one.But when dry seeds of the three crops are irradiated by 3.5-22keV X-rays,the sequence of their sensitivity to radiation can be changed.for irradiation of 0.6-3keV ultra soft X-rays,0.40-0.90 of the seedlings of the first generation appear mutation of striped chlorophyll defect.This biological effect has never been found for irradiation of other rays.

  6. Biological effect of fast neutrons

    International Nuclear Information System (INIS)

    The efficiency of fast neutrons of the energy range from 1.7 to 5 MeV in reducing the reticulocyte count and in diminishing the spleen weight was studied in male NMRI mice and compared with the effects of 250 kV X-rays. The neutron induced decrease of reticulocyte number in the peripheral blood is complete two days after irradiation. At this time even low doses cause a maximal effect. The relation between the rise of effect and the increase of exposure is great in the range of low doses and small in high doses. The relative biological effectiveness of neutrons in reducing the reticulocyte count is 2.5 after low doses and 1.2 after high doses. The spleen of irradiated mice shows a marked loss of weight, the lowest weight values are observed at the second day after irradiation. The relative effectiveness of neutrons in diminishing the spleen weight is 2.1 at low doses, the RBE decreases to 1.4 and rises again to 1.9 at higher doses. These results are compared with previous findings on mortality response and leucocyte and lymphocyte decrease in mice after neutron irradiation. Reticulocyte and lymphocyte count are found to be useful indicators for the detection and evaluation of neutron damage in the sublethal dose range. (orig.)

  7. Biological radiation effects

    International Nuclear Information System (INIS)

    This work examines ionizing radiations: what they are, where they come from, their actions and consequences, finally the norms and preventive measures necessary to avoid serious contamination, whether the individual or the population in general is involved. Man has always been exposed to natural irradiation, but owing to the growing use of ionizing radiations both in medicine and in industry, not to mention nuclear tests and their use as an argument of dissuasion, the irradiation of human beings is increasing daily. Radioactive contamination does remain latent, apart from acute cases, but this is where the danger lies since the consequences may not appear until long after the irradiation. Of all biological effects due to the action of radioelements the genetic risk is one of the most important, affecting the entire population and especially the generations to come. The risk of cancer and leukemia induction plays a substantial part also since a large number of people may be concerned, depending on the mode of contamination involved. All these long-term dangers do not of course exclude the various general or local effects to which the individual alone may be exposed and which sometimes constitute a threat to life. As a result the use of ionizing radiations must be limited and should only be involved if no other process can serve instead. The regulations governing radioelements must be stringent and their application strictly supervised for the better protection of man. This protection must be not only individual but also collective since pollution exists in air, water and land passes to plants and animals and finally reaches the last link in the food chain, man

  8. New detection modules for gamma, beta and X-ray cameras

    International Nuclear Information System (INIS)

    Full text: Ideas ASA is developing new detection modules for gamma, beta and X-ray cameras. Recent developments focus on modules using various semi-conductor materials (CZT, HgI, Si). The development includes ASIC design, detector module development, and implementation in camera heads. In this presentation we describe the characteristics of important ASICs and its properties in terms of electronic noise, and the modes for measuring signals (switched current modes, sparsified modes, self triggered modes). The ASICs are specific for detectors and applications. We describe recent developments using various semi - conductor materials. We describe important design aspects for medical applications and in life science (SPECT, beta, X-ray cameras)

  9. Effects of beta/gamma radiation on nuclear waste glasses

    International Nuclear Information System (INIS)

    A key challenge in the disposal of high-level nuclear waste (HLW) in glass waste forms is the development of models of long-term performance based on sound scientific understanding of relevant phenomena. Beta decay of fission products is one source of radiation that can impact the performance of HLW glasses through the interactions of the emitted β-particles and g-rays with the atoms in the glass by ionization processes. Fused silica, alkali silicate glasses, alkali borosilicate glasses, and nuclear waste glasses are all susceptible to radiation effects from ionization. In simple glasses, defects (e.g., non-bridging oxygen and interstitial molecular oxygen) are observed experimentally. In more complex glasses, including nuclear waste glasses, similar defects are expected, and changes in microstructure, such as the formation of bubbles, have been reported. The current state of knowledge regarding the effects of β/γ radiation on the properties and microstructure of nuclear waste glasses are reviewed. (author)

  10. Dopaminergic and beta-adrenergic effects on gastric antral motility

    DEFF Research Database (Denmark)

    Bech, K; Hovendal, C P; Gottrup, F;

    1984-01-01

    bethanechol or pentagastrin inducing motor activity patterns as in the phase III of the MMC and the digestive state respectively. The stimulated antral motility was dose-dependently inhibited by dopamine. The effect was significantly blocked by specifically acting dopaminergic blockers, while alpha- and beta......-adrenergic blockers were without any significant effects. Dose-response experiments with bethanechol and dopamine showed inhibition of a non-competitive type. Isoprenaline was used alone and in conjunction with selective blockade of beta 1- and beta 2-receptors during infusion of bethanechol which induces a pattern...... similar to phase III in the migrating myoelectric complex. The stimulated antral motility was dose-dependently inhibited by isoprenaline. The effect could be significantly blocked by propranolol (beta 1 + beta 2-adrenoceptor blocker) and by using in conjunction the beta 1-adrenoceptor blocker practolol...

  11. Biological effectiveness of fission neutrons

    International Nuclear Information System (INIS)

    Human peripheral blood lymphocytes were exposed to the uranium fission neutrons with different energy spectra, and the effects of changing pattern of energy spectrum on the relative biological effectiveness (RBE) were studied by analyzing dose-response relationship of chromosome aberrations. When the contribution of contaminated gamma-rays was subtracted, the efficiency of chromosomal response to the neutron dose was found to be refractory to the difference in the energy spectrum while the mean energy ranged from 2 MeV to 27 keV. This chromosomal refractoriness to energy spectrum may be explained by the similarity of energy spectrum for kerma contribution; most of the doses being given by neutrons with energy above 50 keV. Small doses given by short tracks may be less efficient. A comparison of these observations with chromosome aberration frequencies in lymphocytes of A-bomb survivors leads to somewhat higher estimate of neutron dose in Hiroshima than the estimate by the recently revised dosimetry system, DS86. (author)

  12. Quantum Effects in Biological Systems

    CERN Document Server

    2016-01-01

    Since the last decade the study of quantum mechanical phenomena in biological systems has become a vibrant field of research. Initially sparked by evidence of quantum effects in energy transport that is instrumental for photosynthesis, quantum biology asks the question of how methods and models from quantum theory can help us to understand fundamental mechanisms in living organisms. This approach entails a paradigm change challenging the related disciplines: The successful framework of quantum theory is taken out of its low-temperature, microscopic regimes and applied to hot and dense macroscopic environments, thereby extending the toolbox of biology and biochemistry at the same time. The Quantum Effects in Biological Systems conference is a platform for researchers from biology, chemistry and physics to present and discuss the latest developments in the field of quantum biology. After meetings in Lisbon (2009), Harvard (2010), Ulm (2011), Berkeley (2012), Vienna (2013), Singapore (2014) and Florence (2015),...

  13. The relevance of dose for low-energy beta emitters

    International Nuclear Information System (INIS)

    Specific issues in risk assessment for low-energy beta emitters include specification of the radiation weighting factor, values of relative biological effectiveness for specific or accurate risk estimates, non-uniformities of dose within tissues and cells, and use of standard tissue weighting factors for non-uniform situations. Unusual features of low-energy beta emitters include: increased average ionisation density on subcellular (and cellular) scales; short ranges of the beta electrons; non-uniformity of the absorbed dose over subcellular, cellular, and tissue dimensions; reduced hit frequencies; nuclear transmutations; different chemical forms, influencing biokinetics and dose distributions; and large isotopic mass differences, particularly in the case of tritium and hydrogen. Many of these features are not included explicitly in conventional radiation protection dosimetry, although they may be partly included in experimental determinations of relative biological effectiveness. Theoretical and experimental studies have shown low-energy electrons to be particularly efficient in producing double-strand breaks in DNA, including complex double-strand breaks. Hence, on fundamental grounds, tritium beta particles should be expected to have greater biological effectiveness per unit absorbed dose than 60Co gamma-rays or orthovoltage x-rays. For practical purposes, and in view of the paucity of epidemiological estimates of risk from low-energy electrons, consideration should be given to applying a raised relative biological effectiveness, say of value 2, to all low-energy internal emitters, including beta particles and soft x-ray emissions.

  14. Decomposition of beta-ray induced ESR spectra of fossil tooth enamel

    Energy Technology Data Exchange (ETDEWEB)

    Joannes-Boyau, Renaud, E-mail: renaud.joannes-boyau@anu.edu.a [Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 (Australia); Gruen, Rainer [Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 (Australia)

    2011-03-15

    Two fossil tooth enamel fragments were irradiated with beta rays, one through the outer surface, the other through the dentine-enamel junction. The angular ESR spectra of the two fragments were decomposed using an automated simulated annealing (SA) procedure, which is particularly well suited to separate overlapping signals. Beta irradiation generated different qualitative and quantitative responses to previous gamma irradiation experiments. Similar to gamma rays, the beta irradiation created both non-oriented and oriented CO{sub 2}{sup -} radicals. In contrast to gamma irradiation, which only created orthorhombic oriented CO{sub 2}{sup -} radicals, both axial and orthorhombic CO{sub 2}{sup -} radicals were extracted after beta irradiation. Furthermore, gamma irradiation created significantly more non-oriented radicals than beta irradiation. Altogether, the radical distribution created by beta irradiation resembled that of the natural sample, which had been exposed to environmental irradiation over several hundreds of thousands of years. The natural sample contained 9% non-orientated CO{sub 2}{sup -} radicals and a mix of orthorhombic to axial CO{sub 2}{sup -} radicals in the ratio of 35:65. The beta induced spectra of the fragment irradiated through the outer surface contained 9% non-orientated CO{sub 2}{sup -} radicals and a mix of orthorhombic to axial CO{sub 2}{sup -} radicals in the ratio of 45:55, while for the other sample these values were 19% and 59:41, respectively. The angle between the axial and orthorhombic CO{sub 2}{sup -} radicals is around 23{sup o} in both natural and beta irradiation components. This indicates that the radicals produced by the different irradiation modes are located in the same positions in the hydroxyapatite crystals. The higher percentage of non-oriented CO{sub 2}{sup -} radicals closer to the dentine-enamel junction points to interprismatic zones for their possible location.

  15. Directional distributions of beta-rays emitted from oriented nuclei

    International Nuclear Information System (INIS)

    A unique ultralow-temperature nuclear orientation facility was developed with which the directional distributions of β-rays emitted from statically polarized nuclei can be observed, for the first time, at many angles with respect to the polarization axis. Nuclei can be polarized in bulk by imbedding them in an appropriate ferromagnetic host, which is cooled to near absolute zero temperature and is magnetized to saturation with an externally applied field. The polarization axis is defined by the direction of this applied field. The two distinguishing features of the new system are the following: the necessary temperature of about 0.010K can be maintained very accurately for as long as is necessary by a 3He/4He dilution refrigerator; and the polarization axis can be rotated, while the source and the detector are kept stationary, by varying the external fields applied by intersecting magnetic loops. These loops leak a negligible amount of magnetic flux into the region traversed by the β rays, and thus leave β-ray trajectories essentially unaltered. In the first experiment performed on the facility, the angular dependence of the parity-violating term in the directional distribution function for β rays emitted from polarized 60Co nuclei was directly measured for the first time. The results were found to be consistent with the accepted theories of nuclear β decay. Additional fundamental experiments possible with this new facility involving parity violation, isospin nonconservation, and time-reversal invariance are discussed

  16. Early and continuing effects of combined alpha and beta irradiation of the lung:

    Energy Technology Data Exchange (ETDEWEB)

    Scott, B.R.; Hahn, F.F.; Snipes, M.B.; Newton, G.J.; Eidson, A.F.; Mauderly, J.L.; Boecker, B.B.

    1988-03-01

    This report summarizes an inhalation exposure experiment that concerns early and continuing effects of combined alpha and beta irradiation of the lung of rats. Both morbidity at 18 months and mortality within 18 months after exposure were examined for rats exposed to the beta-emitter /sup 147/Pm, the alpha-emitter /sup 238/Pu, or both combined. The results were used to validate hazard-function models that were developed (1)for pulmonary functional morbidity at 18 months and (2) for lethality from radiation pneumonitis and pulmonary fibrosis within 18 months. Both models were found to adequately predict the experimental observations after combined chronic alpha and beta irradiation of the lung. A relative biological effectiveness of approximately 7 was obtained for /sup 238/Pu alpha radiation compared to /sup 147/Pm beta radiation for both pulmonary functional morbidity and lethality from radiation pneumonitis and pulmonary fibrosis. 12 refs., 16 figs., 11 tabs.

  17. X-ray microscopy of live biological micro-organisms

    Science.gov (United States)

    Raja Al-Ani, Ma'an Nassar

    Real-time, compact x-ray microscopy has the potential to benefit many scientific fields, including microbiology, pharmacology, organic chemistry, and physics. Single frame x-ray micro-radiography, produced by a compact, solid-state laser plasma source, allows scientists to use x-ray emission for elemental analysis, and to observe biological specimens in their natural state. In this study, x-ray images of mouse kidney tissue, live bacteria, Pseudomonas aeruginosa and Burkholderia cepacia, and the bacteria's interaction with the antibiotic gentamicin, are examined using x-ray microscopy. For the purposes of comparing between confocal microscopy and x-ray microscopy, we introduced to our work the technique of gold labeling. Indirect immunofluorescence staining and immuno-gold labeling were applied on human lymphocytes and human tumor cells. Differential interference contrast microscopy (DIC) showed the lymphocyte body and nucleus, as did x-ray microscopy. However, the high resolution of x-ray microscopy allows us to differentiate between the gold particles bound to the antibodies and the free gold. A compact, tabletop Nd: glass laser is used in this study to produce x-rays from an Yttrium target. An atomic force microscope is used to scan the x-ray images from the developed photo-resist. The use of compact, tabletop laser plasma sources, in conjunction with x-ray microscopy, is a new technique that has great potential as a flexible, user-friendly scientific research tool.

  18. The biological effectiveness of antiproton irradiation

    DEFF Research Database (Denmark)

    Holzscheiter, Michael H.; Bassler, Niels; Agazaryan, Nzhde;

    2006-01-01

    Background and purpose: Antiprotons travel through tissue in a manner similar to that for protons until they reach the end of their range where they annihilate and deposit additional energy. This makes them potentially interesting for radiotherapy. The aim of this study was to conduct the first...... ever measurements of the biological effectiveness of antiprotons. Materials and methods: V79 cells were suspended in a semi-solid matrix and irradiated with 46.7 MeV antiprotons, 48 MeV protons, or 60Co c-rays. Clonogenic survival was determined as a function of depth along the particle beams. Dose and...... particle fluence response relationships were constructed from data in the plateau and Bragg peak regions of the beams and used to assess the biological effectiveness. Results: Due to uncertainties in antiproton dosimetry we defined a new term, called the biologically effective dose ratio (BEDR), which...

  19. Effect of tissue inhomogeneity on beta dose calculation

    International Nuclear Information System (INIS)

    Appropriate monoclonal antibodies labeled with beta-emitting nuclides of high specific activity have been suggested for treatment of specific tumors. In a homogeneous medium the radiation dose rate distribution R due to a distributed activity distribution C can be calculated by convolution of the beta dose point kernel of the radionuclide in soft tissue with C. Prototype computer programs using Fast Fourier Transform techniques have been developed to evaluate the three dimensional spatial convolution efficiently. To study the effect of tissue inhomogeneity on R, the authors simulated a soft tissue-bone interface by a polystyrene (PST)-aluminum (A1) interface and considered the backscattering of beta rays from a point source and a plane source of 32P. LiF thermoluminescent dosimeters were used. With the point source at the PST-A1 interface, R at 0-31, 125-156, and 283-314 mg/cm2 separations from the interface were increased by (12 +/- 3)%, (8 +/-2)%, and (3 +/- 2)%, respectively, compared with a PST-PST interface. With the plane source, the increases were (8 +/- 3)%, (6 +/- 3)%, and (5 +/- 5)% for separations of 23-58, 150-184, and 277-311 mg/cm2, respectively. With the point source at a PST-air interface to simulate soft tissue-air interface, R at 0-31, 139-170, and 283-314 mg/cm2 from the interface were decreased by (25 +/- 4)%, (11 +/- 7)%, and (5 +/-2)%, respectively. The changes in R have also been measured with degraded spectra of 32P. Comparison of the experimental data with Monte Carlo calculation and the Two-Group method of calculation will be discussed. 20 references, 6 figures, 2 tables

  20. Genetical, Cytological and Biological Studies of OWSWF, Chrysomya bezziana Exposed to Gamma Rays: III.Effect on Flight Ability Index and Mating competitiveness Value

    International Nuclear Information System (INIS)

    Results showed that the Flight Ability Index (FAI) of Old World Screwworm (OWS) fly Ghrysomya bezziana adults which emerged form irradiated pupae with 30, 45, 60 and 75 Gy of gamma ray was not affected under Lab. conditions but it was effected under field condition. Result of mating competitiveness of adults emerged from irradiated pupae with 30 and 60 Gy of gamma rays and mated as follows: a - Irradiated males: unirradiated males:unirradiated females. b- Irradiated females: unirradiated females: unirradiated males. c- Irradiated females:Irradiated males:unirradiated females: unirradiated males. Showed that males irradiated with 30 Gy and mated as in a: reduced and have the percentages of egg hatching and have a very good competitiveness value and this dose which caused complete sterility in C. bezziana had no effect on this parameter, moreover, 30 Gy gamma rays caused an effect to females which mated as in b: Finally the results showed that irradiated males and females with 30 Gy as in c: had a very good mating competitiveness value.

  1. Counting efficiency for radionuclides decaying by beta and gamma-ray emission

    International Nuclear Information System (INIS)

    In this paper, counting efficiency vs figure of merit for beta and gamma-ray emitters has been computed. It is assumed that the decay scheme has only a gamma level and the beta-ray emission may be coincident with the gamma-rays or the internal-conversion electrons. The radionuclides tabulated are: 20O, 20F, 28Al, 35P,41Ar, 42K, 47Se, 62Fe, 66Cu, 81Ge, 86Rb, 104Rh, 108Ru, 112Pd, 121Sn(m), 122In, 129I, 141Ce, 142Pr, 151Sm, 170Tm, 171Tm, 194Os, 203Hg, 205Hg, 210Pb, 225Ra, 244Am(m). It has been assumed that the liquid is a toluene based scintillator solution in standard glass vials containing 10 cm3. (Author)

  2. High-dose dosimetry of beta rays using blue beryl dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Lucas S. do, E-mail: lsatiro@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Watanabe, Shigueo; Bittencour, Jose F., E-mail: Lacifid@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica. Departamento de Fisica Nuclear

    2015-07-01

    High dose radiation is widely used in industrial applications as sterilization of medical products, improvement of materials properties, color enhancement of jewelry stones, etc. The radiation dosimetry of high doses is quite important for these applications. In this work we have investigated the usage of blue beryl crystal also known as aquamarine in high dose dosimetry of beta rays. Some works have shown that silicate minerals exhibit a good Thermoluminescent response when irradiated up to 2000 kGy of gamma rays. Here, we have produced small beryl pellets of approximately 5 mm in diameter and 3 mm thickness to measure high doses of beta rays produced at an electron accelerator at IPEN. Twelve beryl dosimeters were made and six of them were irradiated from 10kGy up to 100 kGy. The technique used to create a calibration curve was the thermoluminescence using the glow peak at 310°C. (author)

  3. Effects of calcium impurity on phase relationship, ionic conductivity and microstructure of Na$^{+}$-$\\beta/beta"$-alumina solid electrolyte

    Indian Academy of Sciences (India)

    SUNG-TAE LEE; DAE-HAN LEE; SANG-MIN LEE; SANG-SOO HAN; SANG-HYUNG LEE; SUNG-KI LIM

    2016-06-01

    Ca-doped Na$^{+}$-$\\beta/beta"$-alumina was synthesized using a solid-state reaction. The changes in the properties of Na$^{+}$-$\\beta/beta"$-alumina resulting from the presence of Ca impurity were studied. Ca (0–5 wt%) was added to the respective samples, which were then sintered. The specimens were characterized using X-ray diffraction, scanningelectron microscopy, densimetry and impedance analysis. In the sintered specimens, the $\\beta"$-alumina phase fraction decreased as Ca content increased, whereas the relative sintered density increased. The surface morphology of Cadoped Na$^{+}$-$\\beta/beta"$-alumina specimens showed a Ca-rich layer, which was the main cause of increase in the specificresistance.

  4. Biological radiation effects

    International Nuclear Information System (INIS)

    The stages of processes leading to radiation damage are studied, as well as, the direct and indirect mechanics of its production. The radiation effects on nucleic acid and protein macro moleculas are treated. The physical and chemical factors that modify radiosensibility are analysed, in particular the oxygen effects, the sensibilization by analogues of nitrogen bases, post-effects, chemical protection and inherent cell factors. Consideration is given to restoration processes by excision of injured fragments, the bloching of the excision restoration processes, the restoration of lesions caused by ionizing radiations and to the restoration by genetic recombination. Referring to somatic effects of radiation, the early ones and the acute syndrome of radiation are discussed. The difference of radiosensibility observed in mammalian cells and main observable alterations in tissues and organs are commented. Referring to delayed radiation effects, carcinogeneses, alterations of life span, effects on growth and development, as well as localized effects, are also discussed

  5. Experimental method for reactor-noise measurements of effective beta

    International Nuclear Information System (INIS)

    A variance-to-mean noise technique, modified to eliminate systematic errors from drifting of reactor power, has been used to infer integral values of effective beta for uranium and plutonium fueled fast reactor modk-ups. The measurement technique, including corrections for a finite detector-electrometer time response, is described together with preliminary beta measurement results

  6. The Secret XUV Lives of Cepheids: FUV/X-ray Observations of Polaris and beta Dor

    CERN Document Server

    Engle, Scott G; DePasquale, Joseph; Evans, Nancy

    2009-01-01

    We report on the surprising recent discovery of strong FUV emissions in two bright, nearby Classical Cepheids from analyses of FUSE archival observations and one of our own approved observations just prior to the failure of the satellite. Polaris and beta Dor are currently the only two Cepheids to have been observed with FUSE, and beta Dor is the only one to have multiple spectra. Both Cepheids show strong C III (977A, 1176A) and O VI (1032A, 1038A) emissions, indicative of 50,000-500,000 K plasma, well above the photospheric temperatures of the stars. More remarkably, beta Dor displays variability in the FUV emission strengths which appears to be correlated to its 9.84-d pulsation period. This phenomenon has never before been observed in Cepheids. The FUV studies are presented along with our recent Chandra/XMM X-ray observations of Polaris and beta Dor, in which X-ray detections were found for both stars (as well as for the prototype Classical Cepheid, delta Cep). Further X-ray observations have been propose...

  7. Design and characteristics of beta-excited X-ray sources

    International Nuclear Information System (INIS)

    The paper reports on recent work on beta-excited X-ray sources. Results of detailed experimental investigation on the X-rays produced by the fission products Pm147, Kr85 and Sr90 are described. X-ray yields and spectral distributions have been studied for target materials ranging from copper to uranium and in a variety of source-target geometries (transmission target, reflection target, sandwich target, intimate source-target mixtures). To interpret the experimental results, an analytical treatment of the processes involved in X-ray production by beta particles has been developed and is outlined. By taking into account bremsstrahlung, K-shell ionization, and fluorescent X-ray excitation, a convenient mathematical formulation may be derived for photon spectra and yields as functions of maximum β-energy, target thickness and source configuration. The agreement between calculated and experimentally determined yields is excellent and confirms the merit of the analysis. It thus becomes possible to optimize the design of isotopic X-ray sources for specific applications. Kr85 and Pm147 prototype sources have been designed and 'their performance in thickness and composition-analysis measurements is discussed. A high level Pm147 source for industrial radiography has also been designed and its performance, along with the utility of image intensifiers to extend its applicability, is considered. Finally, a general review of potentialities, advantages and limitations of isotopic X-ray sources is given. (author)

  8. Climatic and biological effects

    International Nuclear Information System (INIS)

    The ozone-climate problem has received considerable attention since concern was raised regarding possible threats to stratospheric ozone. Early climatic assessments of reduced ozone focused on the direct solar and longwave effects. Now a number of important feedback mechanisms are recognized as contributing significantly to indirect climatic effects. Although the focus in this chapter is on the climatic effect of reduced ozone, the discussion must include other trace gases as well. Many of the trace gases that interact photochemically to reduce ozone also have important radiative properties. Examples are chlorofluorocarbons (CFCl3 and CF2Cl2), nitrous oxide (N2O), and methane (CH4). Other gases, such as CO2, affect the temperature profile in the atmosphere, which can have an indirect effect on ozone through temperature-dependent reaction rates. The change in ozone, in turn, alters the change in temperature. The direct radiative effect of gases comes about through absorption of solar radiation and absorption and emission of longwave radiation (also referred to as thermal, terrestrial, or infrared radiation). The spectral distribution of solar and longwave radiation is shown. The principal gaseous absorbers of solar radiation are O2 and O3 in the stratosphere and H2O in the troposphere. As discussed in Chapter 2, ozone has absorption bands in the ultraviolet (uv) and visible regions of the solar spectrum. Water vapor absorbs primarily in the near-infrared spectral region

  9. Adverse effects of beta-agonists: are they clinically relevant?

    Science.gov (United States)

    Abramson, Michael J; Walters, Julia; Walters, E Haydn

    2003-01-01

    Inhaled beta(2)-adrenoceptor agonists (beta(2)-agonists) are the most commonly used asthma medications in many Western countries. Minor adverse effects such as palpitations, tremor, headache and metabolic effects are predictable and dose related. Time series studies suggested an association between the relatively nonselective beta-agonist fenoterol and asthma deaths. Three case-control studies confirmed that among patients prescribed fenoterol, the risk of death was significantly elevated even after controlling for the severity of asthma. The Saskatchewan study not only found an increased risk of death among patients dispensed fenoterol, but also suggested this might be a class effect of beta(2)-agonists. However, in subsequent studies, the long-acting beta(2)-agonist salmeterol was not associated with increased asthma mortality. In a case-control study blood albuterol (salbutamol) concentrations were found to be 2.5 times higher among patients who died of asthma compared with controls. It is speculated that such toxic concentrations could cause tachyarrhythmias under conditions of hypoxia and hypokalemia. The risk of asthma exacerbations and near-fatal attacks may also be increased among patients dispensed fenoterol, but this association may be largely due to confounding by severity. Although salmeterol does not appear to increase the risk of near-fatal attacks, there is a consistent association with the use of nebulized beta(2)-agonists. Nebulized and oral beta(2)-agonists are also associated with an increased risk of cardiovascular death, ischemic heart disease and cardiac failure. Caution should be exercised when first prescribing a beta-agonist for patients with cardiovascular disease. A potential mechanism for adverse effects with regular use of beta(2)-agonists is tachyphylaxis. Tachyphylaxis to the bronchodilator effects of long-acting beta(2)-agonists can occur, but has been consistently demonstrated only for formoterol (eformoterol) a full agonist, rather

  10. Biological control of Polymyxa betae, fungal vector of rhizomania disease of sugar beets in greenhouse conditions

    OpenAIRE

    Naraghi Laleh; Heydari Asghar; Askari Hassan; Pourrahim Reza; Marzban Rasoul

    2014-01-01

    Rhizomania is one of the most important diseases of sugar beet around the world – including in Iran. The disease causes a severe decrease in sugar yield and is a limiting factor in sugar beet cultivation. Control of the disease is very difficult due to the long-term survival of its fungal vector (Polymyxa betae) in the soil. In this study, we investigated the effects of antagonistic fungal isolates on the population of the resting structure (cystosorus) of P. betae, under greenhouse condition...

  11. Review of relative biological effectiveness dependence on linear energy transfer for low-LET radiations

    International Nuclear Information System (INIS)

    Information on Japanese A-bomb survivors exposed to gamma radiation has been used to estimate cancer risks for the whole range of photon (x-rays) and electron energies which are commonly encountered by radiation workers in the work place or by patients and workers in diagnostic radiology. However, there is some uncertainty regarding the radiation effectiveness of various low-linear energy transfer (low-LET) radiations (x-rays, gamma radiation and electrons). In this paper we review information on the effectiveness of low-LET radiations on the basis of epidemiological and in vitro radiobiological studies. Data from various experimental studies for chromosome aberrations and cell transformation in human lymphocytes and from epidemiological studies of the Japanese A-bomb survivors, patients medically exposed to radiation for diagnostic and therapeutic procedures, and occupational exposures of nuclear workers are considered. On the basis of in vitro cellular radiobiology, there is considerable evidence that the relative biological effectiveness (RBE) of high-energy low-LET radiation (gamma radiation, electrons) is less than that of low-energy low-LET radiation (x-rays, betas). This is a factor of about 3 to 4 for 29 kVp x-rays (e.g. as in diagnostic radiation exposures of the female breast) and for tritium beta-rays (encountered in parts of the nuclear industry) relative to Co-60 gamma radiation and 2-5 MeV gamma-rays (as received by the Japanese A-bomb survivors). In epidemiological studies, although for thyroid and breast cancer there appears to be a small tendency for the excess relative risks to decrease as the radiation energy increases for low-LET radiations, it is not statistically feasible to draw any conclusion regarding an underlying dependence of cancer risk on LET for the nominally low-LET radiations. (review)

  12. H-$\\beta$ Line Width and the UV-X-ray Spectra of Luminous AGN

    CERN Document Server

    Wills, B J; Yuan Jian Min

    2000-01-01

    The width of the broad H-beta emission line is the primary defining characteristic of the NLS1 class. This parameter is also an important component of Boroson and Green's optical Eigenvector 1 (EV1), which links steeper soft X-ray spectra with narrower H-beta emission, stronger H-beta blue wing, stronger optical Fe II emission, and weaker [O III] lambda 5007. Potentially, EV1 represents a fundamental physical process linking the dynamics of fueling and outflow with the accretion rate. We attempted to understand these relationships by extending the optical spectra into the UV for a sample of 22 QSOs with high quality soft-X-ray spectra, and discovered a whole new set of UV relationships that suggest that high accretion rates are linked to dense gas and perhaps nuclear starbursts. While it has been argued that narrow (BLR) H-beta means low Black Hole mass in luminous NLS1s, the C IV, lambda 1549 and Ly alpha emission lines are broader, perhaps the result of outflows driven by their high Eddington accretion rate...

  13. Biological radiation effects

    International Nuclear Information System (INIS)

    Everyone is exposed to a complex mix of electromagnetic fields (EMF) of different frequencies that permeate our environment. Exposures to these EMF are increasing significantly as technology advances unabated and new applications are found. Technological progress in the broadest sense of the word has always been associated with various hazards and risks, both perceived and real. The industrial, commercial and household application on EMF is no exception. Throughout the world, the general public is concerned that exposure to EMF from such sources as high voltage power lines, broadcasting networks, mobile telephones and their base stations could lead to adverse health consequences, especially in children. As a result, the construction of new power lines and broadcasting and mobile telephone network has met with considerable opposition in many countries. Public exposure to EMF is regulated by a variety of voluntary and legal limits, together with various national safety standards. Guidelines are designed to avoid all identified hazards, from short and long term exposure, recommended limits. The aim of this paper is to report the summary of the actual scientific knowledge about the potential health effects and hazards due to man made EMF and the new tendencies of the social and political choices

  14. Biological effects of mutagenic agents

    International Nuclear Information System (INIS)

    There is an increasing body of evidence that mutagenic agents (biological, chemical and physical) play an important role in the etiology of human diseases. Mutations may occur in the germinal as well as in the somatic cells. Mutations of the germ cells may result on infertility or fertilization of damaged cells, the later leading to abortion or birth of a malformed fetus. Somatic-cells mutations may have various biological effects, depending on the period of the human life at which the mutation occurs. If it occurs during the prenatal life, a teratogenic or carcinogenic effect will be observed. If the somatic cell is damaged during the postnatal life, this will lead to neoplastic transformation. Therefore it is extremely important to know the mutagenic, teratogenic and carcinogenic effects of various biological, chemical and physical agents in order to eliminate them from our environment. (author). 13 refs, 4 figs, 1 tab

  15.  Generation of low-flux X-ray micro-planar beams and their biological effect on a murine subcutaneous tumor model.

    Science.gov (United States)

    Hong, Zhengshan; Zenkoh, Junko; Le, Biao; Gerelchuluun, Ariungerel; Suzuki, Kenshi; Moritake, Takashi; Washio, Masakazu; Urakawa, Junji; Tsuboi, Koji

    2015-09-01

    We generated low-flux X-ray micro-planar beams (MPBs) using a laboratory-scale industrial X-ray generator (60 kV/20 mA) with custom-made collimators with three different peak/pitch widths (50/200 μm, 100/400 μm, 50/400 μm). To evaluate normal skin reactions, the thighs of C3H/HeN mice were exposed to 100 and 200 Gy MPBs in comparison with broad beams (20, 30, 40, 50, 60 Gy). Antitumor effects of MPBs were evaluated in C3H/HeN mice with subcutaneous tumors (SCCVII). After the tumors were irradiated with 100 and 200 Gy MPBs and 20 and 30 Gy broad beams, the tumor sizes were measured and survival analyses were performed. In addition, the tumors were excised and immunohistochemically examined to detect γ-H2AX, ki67 and CD34. It was shown that antitumor effects of 200 Gy MPBs at 50/200 μm and 100/400 μm were significantly greater than those of 20 Gy broad beams, and were comparable with 30 Gy broad beams. γ-H2AX-positive cells demonstrated clear stripe-patterns after MPB irradiation; the pattern gradually faded and intermixed over 24 h. The chronological changes in ki67 positivity did not differ between MPBs and broad beams, whereas the CD34-positive area decreased significantly more in MPBs than in broad beams. In addition, it was shown that skin injury after MPB irradiation was significantly milder when compared with broad-beam irradiation at equivalent doses for achieving the same tumor control effect. Bystander effect and tumor vessel injury may be the mechanism contributing to the efficacy of MPBs. PMID:26141370

  16. Generation of low-flux X-ray micro-planar beams and their biological effect on a murine subcutaneous tumor model

    International Nuclear Information System (INIS)

    We generated low-flux X-ray micro-planar beams (MPBs) using a laboratory-scale industrial X-ray generator (60 kV/20 mA) with custom-made collimators with three different peak/pitch widths (50/200 μm, 100/400 μm, 50/400 μm). To evaluate normal skin reactions, the thighs of C3H/HeN mice were exposed to 100 and 200 Gy MPBs in comparison with broad beams (20, 30, 40, 50, 60 Gy). Antitumor effects of MPBs were evaluated in C3H/HeN mice with subcutaneous tumors (SCCVII). After the tumors were irradiated with 100 and 200 Gy MPBs and 20 and 30 Gy broad beams, the tumor sizes were measured and survival analyses were performed. In addition, the tumors were excised and immunohistochemically examined to detect γ-H2AX, ki67 and CD34. It was shown that antitumor effects of 200 Gy MPBs at 50/200 μm and 100/400 μm were significantly greater than those of 20 Gy broad beams, and were comparable with 30 Gy broad beams. γ-H2AX-positive cells demonstrated clear stripe-patterns after MPB irradiation; the pattern gradually faded and intermixed over 24 h. The chronological changes in ki67 positivity did not differ between MPBs and broad beams, whereas the CD34-positive area decreased significantly more in MPBs than in broad beams. In addition, it was shown that skin injury after MPB irradiation was significantly milder when compared with broad-beam irradiation at equivalent doses for achieving the same tumor control effect. Bystander effect and tumor vessel injury may be the mechanism contributing to the efficacy of MPBs. (author)

  17. Beta dose attenuation and calculations of effective grainsize in brick samples

    International Nuclear Information System (INIS)

    An assumption commonly made in estimating the beta-ray contribution to individual quartz grains in bricks and tiles is that prior to extraction all grains used for thermoluminescence (TL) analysis as discrete grains embedded in a clay matrix. We have found in many Utah brick samples that this assumption does not hold, and that the grains used for analysis were largely derived from clumps or agglomerations of quartz grains of up to 3 mm in diameter. If we apply beta-ray attenuation factors appropriate for the grain sizes actually analyzed (150-250 μm) rather than those appropriate for the agglomerations from which the analyzed samples were derived, errors in measurement of β-ray contribution in excess of 50% can result. We present details of a computer model for determining effective grain size in bricks and tiles based upon microscopic examination of sample sections. (author)

  18. Mapping biological composition through quantitative phase and absorption X-ray ptychography

    OpenAIRE

    Jones, Michael W. M.; Elgass, Kirstin; Junker, Mark D.; Luu, Mac B.; Ryan, Michael T; Peele, Andrew G.; van Riessen, Grant A.

    2014-01-01

    Isolating compositional information in biological X-ray imaging can be problematic as such information is conflated with thickness and density variations when viewing in projection through a sample. We demonstrate an effective method for identifying variations in material composition by simultaneously using the quantitative phase and magnitude images provided through soft X-ray ptychography. Using this approach we show significantly increased contrast and improved reliability of the identific...

  19. Searches for Active and Sterile Neutrinos in Beta-Ray Spectra

    CERN Document Server

    Dragoun, Otokar

    2015-01-01

    Although neutrinos are probably the most abundant particles of the universe their mass is yet unknown. The oscillation experiments proved that at least one of the neutrino mass states is heavier than 0.05 eV. Strongly model dependent interpretations of cosmological observations yielded for the sum of the neutrino mass states the values between 0.12 and 1.7 eV. The almost model independent analyses of measured tritium \\b{eta}- spectra provided the upper limit of the effective electron neutrino mass of 2 eV. The upcoming KATRIN experiment aims to achieve ten times higher sensitivity. In this review, we try to summarize the experience of two generations of \\b{eta}-ray spectroscopists who improved the limit of the neutrino mass by three orders of magnitude. We describe important steps in the development of radioactive sources and electron spectrometers, and recapitulate the lessons from now disproved claims for the neutrino of 30 eV mass and the 17 keV neutrino with an admixture larger than 0.07 %. We also pay at...

  20. Biological effectiveness of antiproton annihilation

    CERN Document Server

    Holzscheiter, Michael H.; Bassler, Niels; Beyer, Gerd; De Marco, John J.; Doser, Michael; Ichioka, Toshiyasu; Iwamoto, Keisuke S.; Knudsen, Helge V.; Landua, Rolf; Maggiore, Carl; McBride, William H.; Møller, Søren Pape; Petersen, Jorgen; Smathers, James B.; Skarsgard, Lloyd D.; Solberg, Timothy D.; Uggerhøj, Ulrik I.; Withers, H.Rodney; Vranjes, Sanja; Wong, Michelle; Wouters, Bradly G.

    2004-01-01

    We describe an experiment designed to determine whether or not the densely ionizing particles emanating from the annihilation of antiprotons produce an increase in “biological dose” in the vicinity of the narrow Bragg peak for antiprotons compared to protons. This experiment is the first direct measurement of the biological effects of antiproton annihilation. The experiment has been approved by the CERN Research Board for running at the CERN Antiproton Decelerator (AD) as AD-4/ACE (Antiproton Cell Experiment) and has begun data taking in June of 2003. The background, description and the current status of the experiment are given.

  1. Comparisons of experimental beta-ray spectra important to decay heat predictions with ENSDF [Evaluated Nuclear Structure Data File] evaluations

    International Nuclear Information System (INIS)

    Graphical comparisons of recently obtained experimental beta-ray spectra with predicted beta-ray spectra based on the Evaluated Nuclear Structure Data File are exhibited for 77 fission products having masses 79--99 and 130--146 and lifetimes between 0.17 and 23650 sec. The comparisons range from very poor to excellent. For beta decay of 47 nuclides, estimates are made of ground-state transition intensities. For 14 cases the value in ENSDF gives results in very good agreement with the experimental data. 12 refs., 77 figs., 1 tab

  2. Exchange effects in double beta decay

    International Nuclear Information System (INIS)

    Over the past decade there has been very impressive progress in the laboratory study of double beta decay with very precise limits on 0-neutrino decay in /sup 76/Ge, the imminent prospect of the observation of 2-neutrino decay in /sup 100/Mo and the first laboratory observation of 2-neutrino decay in /sup 82/Se. For the last case, the laboratory rate is in essential agreement with geochemical results and in reasonable agreement with theoretical predictions based on a full shell model calculation. The motivation underlying the resurgence of interest in double beta decay is the hope that the observation of, or limits on the 0-neutrino mode will provide information about the nature of the neutrino. This clearly requires confidence in the nuclear matrix elements involved in the transition. The shell model calculations do not agree well with the geochemical values for /sup 130/Te, which has led to a spate of papers offering specific fixes for the problem. In this contribution we shall not comment on any of the specific nuclear calculations, rather we make some remarks which should be relevant to any model calculation. 11 refs., 1 tab

  3. Beta-glucan ameliorates gamma-rays induced oxidative injury in male Swiss albino rats

    International Nuclear Information System (INIS)

    1,3-beta-D-Glucan is a natural polysaccharide derived from the cell walls of bakers yeast Saccharomyces cerevsiae with immunoenhancing and potent antioxidant effects. This study investigated the pathways through which beta-glucan gavage treatment (50mg/kg) exerts its effect on radiation-induced oxidative damage in male rats. Beta-glucan was given orally to male rats; 3 hours post gamma-irradiation at dose 5Gy, for 10 and 20 days post-irradiation level were assayed, being remarkable indicators in cell oxidative stress. Results pointed out that irradiation at 5Gy significantly depressed all blood parameters, such as erythrocytes count (RBCs), hemoglobin content (Hb), hematocrit value (Hct), total leucocytes count and absolute lymphocytes and neutrophils counts, blood glutathione (GSH) level and conversely elevated level of serum ascorbyl radical (AsR), product of lipid peroxidation (MDA melanodialdehyde), triglycerides and cholesterol. Total leucocytes count and absolute lymphocytes and neutrophils counts, RBCs, Hb, Hct, blood GSH and serum MDA of irradiated animals receiving beta-glucan administration were exhibited significant differences compared to the irradiated group. Marrow count and the percentage of viability and spleenocytes viability were also significantly decreased. Beta-glucan treatment accelerates recovery of cell damage induced by ionizing irradiation through its potential immune-enhancing activity and free radical scavenging ability that is partially mediated through stimulation of immunohaematological system thus could play a role in regulating irradiation complications

  4. Calculation of absorbed dose of anchorage-dependent cells from internal beta-rays irradiation

    International Nuclear Information System (INIS)

    Objective: To elicit the formula of internal dosimetry in anchorage-dependent cells by beta-emitting radionuclides from uniformly distributed volume sources. Methods: By means of the definition of absorbed dose and the MIRD (Medical International Radiation Dose) scheme the formula of internal dosimetry was reasonably deduced. Firstly, studying the systems of suspension culture cells. Then, taking account of the speciality of the systems of the anchorage-dependent cells and the directions of irradiation, the absorbed dose of anchorage -dependent cells was calculated by the accumulated radioactivity, beta-ray energy, and the volume of the cultured systems. Results: The formula of internal dosimetry of suspension culture cells and anchorage-dependent cells were achieved. At the same time, the formula of internal dosimetry of suspension culture cells was compared with that of MIRD and was confirmed accurate. Conclusion: The formula of internal dosimetry is concise, reliable and accurate

  5. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    In this review radiation produced by the nuclear industry is placed into context with other sources of radiation in our world. Human health effects of radiation, derivation of standards and risk estimates are reviewed in this document. The implications of exposing the worker and the general population to radiation generated by nuclear power are assessed. Effects of radiation are also reviewed. Finally, gaps in our knowledge concerning radiation are identified and current research on biological effects, on environmental aspects, and on dosimetry of radiation within AECL and Canada is documented in this report. (author)

  6. Biological effect of radioprotectors. 2. Biological effect of aminothiol radioprotectors

    International Nuclear Information System (INIS)

    The section describes about radio-protective effects on cells and animals, and suppressive effects of mutagenesis and carcinogenesis of aminothiols. Amifostine, NH2-(CH2)3-NH-(CH2)2-SPO3H2 (WR-2721, prodrug), WR-1065 (amifostine-SH form, active principle of WR-2721) and WR-33278 (S-S oxidized form of WR-1065) are mainly discussed. In cells exposed in vitro to 4 mM WR-1065, their survival rates are usually elevated regardless of their types after radiation treatment. In vivo, the author employs the administration dose of 400 mg/kg, which is 2/3 LD50 of amifostine. The prodrug is less toxic than the active form in vivo and reduces the mortality by radiation. Amifostine is an FDA-registered medical for reduction of xerostomia during radiotherapy of head and neck cancer, and of renal toxicity of cisplatin during chemotherapy of advanced ovarian cancer. Hypoxanthine phosphoribosyl transferase (HPRT) mutagenic assay in vitro has revealed anti-mutagenic effect of WR-1065 at 40 M, and also in vivo, the effect is seen in mice after irradiation of X-ray and neutron beam at lower administration doses than that used for lethality test mentioned above. WR-2721 at 400 mg/kg and another aminothiol (WR-151327) have anti-caricinogenic effects in mice against lymphoreticular tumors induced by γ-ray or neutron beam and in rats, at 100 mg/kg WR-2721, against hepatoma development and at 50 mg/kg, against mammary cancer. The compounds are shown to suppress the tumor metastasis in animal models. In vitro, WR-1065 has been shown to reduce the frequency of cell transformation after X-ray or neutron exposure. (T.I.)

  7. Synthesis, Molecular Modelling and Biological Evaluation of Novel Heterodimeric, Multiple Ligands Targeting Cholinesterases and Amyloid Beta

    Directory of Open Access Journals (Sweden)

    Michalina Hebda

    2016-03-01

    Full Text Available Cholinesterases and amyloid beta are one of the major biological targets in the search for a new and efficacious treatment of Alzheimer’s disease. The study describes synthesis and pharmacological evaluation of new compounds designed as dual binding site acetylcholinesterase inhibitors. Among the synthesized compounds, two deserve special attention—compounds 42 and 13. The former is a saccharin derivative and the most potent and selective acetylcholinesterase inhibitor (EeAChE IC50 = 70 nM. Isoindoline-1,3-dione derivative 13 displays balanced inhibitory potency against acetyl- and butyrylcholinesterase (BuChE (EeAChE IC50 = 0.76 μM, EqBuChE IC50 = 0.618 μM, and it inhibits amyloid beta aggregation (35.8% at 10 μM. Kinetic studies show that the developed compounds act as mixed or non-competitive acetylcholinesterase inhibitors. According to molecular modelling studies, they are able to interact with both catalytic and peripheral active sites of the acetylcholinesterase. Their ability to cross the blood-brain barrier (BBB was confirmed in vitro in the parallel artificial membrane permeability BBB assay. These compounds can be used as a solid starting point for further development of novel multifunctional ligands as potential anti-Alzheimer’s agents.

  8. Biological effects of progestins in breast cancer.

    Science.gov (United States)

    Pasqualini, J R; Ebert, C; Chetrite, G S

    2001-12-01

    The action of progestins is derived from many factors: structure, affinity for the progesterone receptor or for other steroid receptors, the target tissue considered, the biological response, the experimental conditions, the dose and metabolic transformation. The proliferative response to progestins in human breast cancer cells is contradictory: some progestins inhibit, others stimulate, have no effect at all, or have a dual action. For instance, medroxyprogesterone acetate has a stimulatory effect on breast cancer cells after a short period of treatment, but this effect becomes inhibitory when treatment is prolonged. It has been demonstrated that, in hormone-dependent breast cancer cells, various progestins (nomegestrol acetate, medrogestone, promegestone) are potent sulfatase inhibitory agents. The progestins can also involve the inhibition of the mRNA expression of this enzyme. In another series of studies it was also demonstrated that some progestins are very active in inhibiting 17beta-hydroxysteroid dehydrogenase for the conversion of estrone to estradiol. More recently it was observed that the progestins promegestone and medrogestone stimulate sulfotransferase for the formation of estrogen sulfates. Consequently, the action of progestins in blocking estradiol formation via sulfatase, or in stimulating the effect on sulfotransferase activity, can open interesting and new possibilities in clinical applications in breast cancer. PMID:12227886

  9. Biology of common beta receptor-signaling cytokines: IL-3, IL-5, and GM-CSF.

    Science.gov (United States)

    Martinez-Moczygemba, Margarita; Huston, David P

    2003-10-01

    IL-3, IL-5, and GM-CSF are related hematopoietic cytoines that are important for allergic inflammation. The receptors for human IL-5, IL-3, and GM-CSF are members of the hematopoietin receptor superfamily and are comprised of a cytokine-specific alpha chain and the common beta chain that is shared among these cytokines for signaling. Each of these cytokines contributes to the differentiation and function of leukocyte subpopulations and have clinical importance in protective immunity and in the pathophysiology of a spectrum of immunologic diseases that are as diverse as allergy and asthma, pulmonary alveolar proteinosis, neurodegenerative diseases, and malignancies. Delineating the biology of these cytokines is enabling the development of new strategies for diagnosing and treating these diseases and modulating immune responses. PMID:14564341

  10. The effects of beta-carotene and vitamin E on erythrocytes lipid peroxidation in beta-thalassemia patients

    Directory of Open Access Journals (Sweden)

    Soleiman Mahjoub

    2007-12-01

    Full Text Available BACKGROUND: Thalassemia is the most common hereditary disease in the world. Thalassemic erythrocytes are exposed to higher oxidative stress and lipid peroxidation. The aim of this study was to investigate the effects of beta-carotene and vitamin E on erythrocytes lipid peroxidation in beta-thalassemia patients.
    METHODS: A prospective double-blind, placebo-controlled study of the effect of beta-carotene and vitamin E on lipid peroxidation in erythrocytes membranes was performed on 120 beta-thalassemia major patients in four groups. The patients were supplemented for 4 weeks as follows: group 1 with beta-carotene (13 mg/day, group 2 with vitamin E (550 mg/day, group 3 with beta-carotene plus vitamin E and group 4 with placebo. We prepared all capsules for 4 roups in the same shape and color. Measurements of serum beta-carotene and vitamin E were performed by high performance
    liquid chromatography. After preparation of ghost cells from blood specimens, malondialdehyde (MDA was determined as index of lipid peroxidation in erythrocytes membranes before and after treatment. RESULTS: The levels of serum beta-carotene and vitamin E were significantly lower and MDA concentrations in erythrocytes membranes were significantly higher in beta-thalassemia patients compared to controls (P<0.001. In groups that treated with vitamin supplements for 4-weeks, lipid peroxidation rates were significantly reduced after treatment (P<0.001, but in placebo group there was not significant difference (P>0.05.
    CONCLUSIONS: Our findings provide evidence that an oral treatment with beta-carotene and vitamin E can significantly reduce lipid peroxidation of erythrocytes membranes and could be useful in management of beta-thalassemia major patients. KEYWORDS: Beta-thalassemia major, beta-carotene, vitamin E, malondialdehyde, lipid peroxidation.

  11. On evaluated nuclear data for beta-delayed gamma rays following of special nuclear materials

    Energy Technology Data Exchange (ETDEWEB)

    Mencarini, Leonardo de H.; Caldeira, Alexandre D., E-mail: mencarini@ieav.cta.b, E-mail: alexdc@ieav.cta.b [Instituto de Estudos Avancados (IEAv/CTA), Sao Jose dos Campos, SP (Brazil)

    2011-07-01

    In this paper, a new type of information available in ENDF is discussed. During a consistency check of the evaluated nuclear data library ENDF/B-VII.0 performed at the Nuclear Data Subdivision of the Institute for Advanced Studies, the size of the files for some materials drew the attention of one of the authors. Almost 94 % of all available information for these special nuclear materials is used to represent the beta-delayed gamma rays following fission. This is the first time this information is included in an ENDF version. (author)

  12. Lise Meitner and the beta-ray energy controversy: An historical perspective

    International Nuclear Information System (INIS)

    Much has been written about the early history of beta-ray research and the controversy it provoked. Many prominent physicists lent their talents to the solution of this puzzling problem. One of the foremost of these was Lise Meitner, conspicuous in the fray not only because of her creative experimental work, but also because of her attachment to a physical principle: the simplicity of nature. This article reviews the sequence of events as they preceded, coincided with, and followed her work on the subject

  13. On evaluated nuclear data for beta-delayed gamma rays following of special nuclear materials

    International Nuclear Information System (INIS)

    In this paper, a new type of information available in ENDF is discussed. During a consistency check of the evaluated nuclear data library ENDF/B-VII.0 performed at the Nuclear Data Subdivision of the Institute for Advanced Studies, the size of the files for some materials drew the attention of one of the authors. Almost 94 % of all available information for these special nuclear materials is used to represent the beta-delayed gamma rays following fission. This is the first time this information is included in an ENDF version. (author)

  14. Biological dosimetry of X-rays by micronuclei study

    International Nuclear Information System (INIS)

    Biological dosimetry consists of estimating absorbed doses for people exposed to radiation by mean biological methods. Several indicators used are based in hematological, biochemical an cytogenetics data, although nowadays without doubt, the cytogenetic method is considered to be the most reliable, in this case, the study of micronuclei in peripheral blood lymphocytes cytokinetic blocked can be related to absorbed dose through an experimental calibration curve. An experimental dose-response curve, using micronuclei assay for X-rays at 250 kVp, 43,79 rads/min and temperature 37 degree celsius has been produced. Experimental data is fitted to model Y=c+ α D+β D2 where. Y is the number micronuclei per cell and D the dose. the curve is compared with those produced elsewhere

  15. Biological Dosimetry of X-rays by micronuclei study

    International Nuclear Information System (INIS)

    Biological dosimetry consists of estimating absorbed doses for people exposed to radiation by mean biological methods. Several indicators used are based in haematological, biochemical an cytogenetics data, although nowadays without doubt, the cytogenetic method is considered to be the most reliable, in this case, the study of micronuclei in peripheral blood lymphocytes citokinetics blocked can be related to absorbed dose through an experimental calibration curve. An experimental dose-response curve, using micronuclei assay for X-rays at 250 kVp, 43,79 rads/min and temperature 37 degree centigree has been produced. Experimental data is fitted to model Y=C+ αD+BD''2 where Y is the number of micronuclei per cell and D the dose. The curve is compared with those produced elsewhere. (Author) 24 refs

  16. Influence of the 192Ir source decay on biological effect

    International Nuclear Information System (INIS)

    Biological effect of the 192Ir high activity source on LA795 tumor of mice and HCT-8 cells have been investigated when decay of the source power from 340.4 GBq to 81.4 GBq no marked difference was found between the two cell survival curves of HCT-8 cells and both of them compared with that of the X-ray irradiation the value of relative biological effect (0.1 survival) was 0.43. On the experiment of tumor LA795 of mice, when the source power was 293.3 GBq and 96.2 GBq, no different biological effect can be seen between the two series of figures. The relative biological effect was 0.55-0.60 (tumor growth delay) comparing with those of X-ray irradiation

  17. Fast x-ray fluorescence microtomography of hydrated biological samples.

    Directory of Open Access Journals (Sweden)

    Enzo Lombi

    Full Text Available Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples.

  18. X-ray lasers for structural and dynamic biology

    International Nuclear Information System (INIS)

    Research opportunities and techniques are reviewed for the application of hard x-ray pulsed free-electron lasers (XFEL) to structural biology. These include the imaging of protein nanocrystals, single particles such as viruses, pump–probe experiments for time-resolved nanocrystallography, and snapshot wide-angle x-ray scattering (WAXS) from molecules in solution. The use of femtosecond exposure times, rather than freezing of samples, as a means of minimizing radiation damage is shown to open up new opportunities for the molecular imaging of biochemical reactions at room temperature in solution. This is possible using a ‘diffract-and-destroy’ mode in which the incident pulse terminates before radiation damage begins. Methods for delivering hundreds of hydrated bioparticles per second (in random orientations) to a pulsed x-ray beam are described. New data analysis approaches are outlined for the correlated fluctuations in fast WAXS, for protein nanocrystals just a few molecules on a side, and for the continuous x-ray scattering from a single virus. Methods for determining the orientation of a molecule from its diffraction pattern are reviewed. Methods for the preparation of protein nanocrystals are also reviewed. New opportunities for solving the phase problem for XFEL data are outlined. A summary of the latest results is given, which now extend to atomic resolution for nanocrystals. Possibilities for time-resolved chemistry using fast WAXS (solution scattering) from mixtures is reviewed, toward the general goal of making molecular movies of biochemical processes. (key issues reviews)

  19. Quantum Effects in Biological Systems

    Science.gov (United States)

    Roy, Sisir

    2014-07-01

    The debates about the trivial and non-trivial effects in biological systems have drawn much attention during the last decade or so. What might these non-trivial sorts of quantum effects be? There is no consensus so far among the physicists and biologists regarding the meaning of "non-trivial quantum effects". However, there is no doubt about the implications of the challenging research into quantum effects relevant to biology such as coherent excitations of biomolecules and photosynthesis, quantum tunneling of protons, van der Waals forces, ultrafast dynamics through conical intersections, and phonon-assisted electron tunneling as the basis for our sense of smell, environment assisted transport of ions and entanglement in ion channels, role of quantum vacuum in consciousness. Several authors have discussed the non-trivial quantum effects and classified them into four broad categories: (a) Quantum life principle; (b) Quantum computing in the brain; (c) Quantum computing in genetics; and (d) Quantum consciousness. First, I will review the above developments. I will then discuss in detail the ion transport in the ion channel and the relevance of quantum theory in brain function. The ion transport in the ion channel plays a key role in information processing by the brain.

  20. Effects of added ZnTCP on mechanical and biological properties of apatite cement

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, K.; Suzuki, K. [Okayama Univ. Dental School (Japan). Dept. of Biomaterials; Miyamoto, Y.; Toh, T.; Yuasa, T.; Nagayama, M. [Tokushima Univ. (Japan). First Dept. of Oral and Maxillofacial Surgery; Ito, A. [National Inst. for Advanced Interdisciplinary Research, MITT, Ibaragi (Japan)

    2001-07-01

    Effects of added Zn doped {beta}-tricalcium phosphate (ZnTCP) on mechanical and biological properties of apatite cement (AC) was studied. Powder X-ray diffractometer revealed that ZnTCP shows no reactivity with AC. The mechanical strength of AC decreased increasing amounts of added ZnTCP. We observed no effect on the setting time of AC when the amount of ZnTCP was 10% or less. Proliferation of the osteoblastic cells was significantly increased on the surface of AC containing 5% ZnTCP when compared with that containing no ZnTCP. In contrast, proliferation of the cells decreased on the surface of AC containing 10% ZnTCP when compared with that free from ZnTCP; indicating cytotoxity. We concluded therefore, that addition of ZnTCP to AC might be useful to enhance the osteoconductivity of AC when release of Zn{sup 2+} can be carefully regulated. (orig.)

  1. Deuterium effects in cancer biology

    International Nuclear Information System (INIS)

    Since its discovery many experiments were conducted for explaining the effects of deuterium on biological systems. It was observed, in many studies, that by increasing the deuterium concentration, structural, metabolic and functional alterations at different extents are produced, which can lead to organism's death. On the other hand effects of concentration reduction are much less studied. Existing data in literature, with regard to intrinsic deuterium reduction effects on different carcinomas are rather scarce. In vitro studies of deuterium level reduction has evidenced an inhibiting effect upon the cellular proliferation in different tumoral cellular lines: M14 cellular lines (human melanoma), PC3 (prostate cancer) and MCF7 (breast cancer). In vivo researches made on experimental tumours, have shown that the deuterium level reduction determines partial or complete regressions in xenotransplanted tumours, while in veterinary oncological clinic, partial or total tumoral regression were observed in different spontaneous tumours in dogs and cats. (authors)

  2. Small-area fiber-coupled scintillation camera for imaging beta-ray distributions intraoperatively

    Science.gov (United States)

    MacDonald, L. R.; Tornai, Martin P.; Levin, C. S.; Park, J.; Atac, Muzaffer; Cline, David B.; Hoffman, Eric G.

    1995-09-01

    A small area, imaging, scintillation probe is being developed for locating small amounts of radio-labeled malignant tissue during surgery. Preliminary in brain surgery, avoiding the removal of excess tissue is a priority. It is possible to locate the main body of a brain tumor both before and during surgery, but once the bulk of the tumor is excised the identification of residual malignant tissue is difficult. A probe that covers an area of 1-2 cm(superscript 2) with an intrinsic resolution of 1-2 mm could locate small tumor masses that pose a threat of recurrence of the disease, and prevent removal of healthy tissue. A pre-operative injection of tumor seeking, beta emitting radiopharmaceutical (e.g. (superscript 18)fluorodeoxyuridine-FDUR-) will label the tumor. The limited range of beta-rays ensures proximity upon successful detection. Plastic scintillators are used for beta detection, and visible light photon counters (VLPCs) detect the scintillation light. For maneuverability in and around the surgical cavity, the scintillators are coupled to the VLPCs via 2 m of optical fiber. An imaging device can cover the tissue bed in a time compatible with surgery, as opposed to a single element detector on the order of 1-2 mm in size with comparable resolution. An imager also distinguishes high background rates (such as from annihilation gammas in FDUR) and concentrations of activity.

  3. The effect of irradiation treatment on Beta-Glucan and protein quality of barley

    International Nuclear Information System (INIS)

    Samples of barley (hordeum vulgare L) grains were tested for nutritional value after being irradiated at dose levels of 10, 20, and 30 KGy. The gross composition of raw and irradiated beans was similar. Soluble protein was reduced by 16.76%, 28.84% and 44.76% when barley grains were irradiated at 10, 20, and 30 KGy, respectively, The amount of water-soluble beta-glucan in raw barley was increased linearly from 1.76 to 2.40 g/100 g of sample as a function of dose. Meanwhile, the effect of irradiation treatment on total beta-glucan (3.90 g/100 g) was insignificant while the level of insoluble beta-glucan was decreased with increasing the dose levels of irradiation. The protein efficiency ratio (PER) of processed barley grains at the doses applied was increased by 6.38%, 12.77%, and 1135%, respectively as compared with the value for raw grains. The data showed that the radiation processing of raw barley grains increased the solubility of beta-glucan, the most anti nutritional factor in the grains and improved the PER in rats. Therefore it could be concluded thal the irradiation treatment (up tp 30 KGy) up-grade the biological value of barley through increase the solubility of Beta-glucan that affect the performance of animals

  4. Biological effects of electromagnetic fields

    International Nuclear Information System (INIS)

    The effects of electromagnetic (em) fields on biological systems were first observed and exploited well over a century ago. Concern over the possible health hazards of human exposure to such fields developed much later. It is now well known that excessive exposure to em fields may have in undesirable biological consequences. Standards were introduced to determine what constitute an excessive exposure and how to avoid it. Current concern over the issue of hazards stems mainly from recent epidemiological studies of exposed populations and also from the results of laboratory experiments in which whole animals are exposed in vivo or tissue and cell cultures exposed in vitro to low levels of irradiation. The underlying fear is the possibility of a causal relationship between chronic exposure to low field levels and some forms of cancer. So far the evidence does not add up to a firm statement on the matter. At present it is not known how and at what level, if at all, can these exposure be harmful to human health. This state of affair does not provide a basis for incorporating the outcome of such research in exposure standards. This paper will give a brief overview of the research in this field and how it is evaluated for the purpose of producing scientifically based standards. The emphasis will be on the physical, biophysical and biological mechanisms implicated in the interaction between em fields and biological systems. Understanding such mechanisms leads not only to a more accurate evaluation of their health implications but also to their optimal utilization, under controlled conditions, in biomedical applications. (author)

  5. TGF-beta1 release from biodegradable polymer microparticles: its effects on marrow stromal osteoblast function

    Science.gov (United States)

    Lu, L.; Yaszemski, M. J.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    2001-01-01

    BACKGROUND: Controlled release of transforming growth factor-beta1 (TGF-beta1) to a bone defect may be beneficial for the induction of a bone regeneration cascade. The objectives of this work were to assess the feasibility of using biodegradable polymer microparticles as carriers for controlled TGF-beta1 delivery and the effects of released TGF-beta1 on the proliferation and differentiation of marrow stromal cells in vitro. METHODS: Recombinant human TGF-beta1 was incorporated into microparticles of blends of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG). Fluorescein isothiocynate-labeled bovine serum albumin (FITC-BSA) was co-encapsulated as a porogen. The effects of PEG content (0, 1, or 5% by weight [wt%]) and buffer pH (3, 5, or 7.4) on the protein release kinetics and the degradation of PLGA were determined in vitro for as long as 28 days. Rat marrow stromal cells were seeded on a biodegradable poly(propylene fumarate) (PPF) substrate. The dose response and biological activity of released TGF-beta1 was determined after 3 days in culture. The effects of TGF-beta1 released from PLGA/PEG microparticles on marrow stromal cell proliferation and osteoblastic differentiation were assessed during a 21-day period. RESULTS: TGF-beta1 was encapsulated along with FITC-BSA into PLGA/PEG blend microparticles and released in a multiphasic fashion including an initial burst for as long as 28 days in vitro. Increasing the initial PEG content resulted in a decreased cumulative mass of released proteins. Aggregation of FITC-BSA occurred at lower buffer pH, which led to decreased release rates of both proteins. The degradation of PLGA was increased at higher PEG content and significantly accelerated at acidic pH conditions. Rat marrow stromal cells cultured on PPF substrates showed a dose response to TGF-beta1 released from the microparticles similar to that of added TGF-beta1, indicating that the activity of TGF-beta1 was retained during microparticle

  6. Biological studies of radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, J.H.

    1949-11-16

    This paper discusses procedures for research on biological effects of radiation, using mouse tissue: activation trace analysis including methods and proceedures for handling samples before during and after irradiation; methods and procedures for ion exchange study; method of separation and recovery of copper, iron, zinc, cobalt, pubidium and cesium. Also included are studies of trace elements with radioactive isotopes: the distribution of cobalt 60, zinc 65, and copper 64 in the cytoplasm and nuclei of normal mice and those with tumors. 16 figs., 2 tabs.

  7. Low level radiation: biological effects

    International Nuclear Information System (INIS)

    It is imperative that physicians and scientists using radiations in health care delivery continue to assess the benefits derived, vs. potential risk, to patients and radiation workers being exposed to radiation in its various forms as part of our health delivery system. Insofar as possible we should assure our patients and ourselves that the benefits outweigh the potential hazards involved. Inferences as to the possible biological effects of low level radiation are generally based on extrapolations from those effects observed and measured following acute exposures to considerably higher doses of radiation. Thus, in order to shed light on the question of the possible biological effects of low level radiation, a wide variety of studies have been carried out using cells in culture and various species of plant and animal life. This manuscript makes reference to some of those studies with indications as to how and why the studies were done and the conclusions that might be drawn there from. In addition reference is made to the handling of this information by scientists, by environmentalists, and by the news media. Unfortunately, in many instances the public has been misled by what has been said and/or written. It is hoped that this presentation will provide an understandable and reasonable perspective on the various appropriate uses of radiation in our lives and how such uses do provide significant improvement in our health and in our quality of life

  8. Near-term and late biological effects of acute and low-dose-rate continuous gamma-ray exposure in dogs and monkeys

    International Nuclear Information System (INIS)

    Monkeys (Macaca mulatta) and dogs (beagle) were given thirteen 100-rad gamma-ray doses at 28-day intervals. The comparative response (inury and recovery) of the hematopoietic system of the two species was observed at 7-day intervals during the exposure regime. At 84 days after the thirteenth gamma-ray dose, the 1300-rad conditioned and control dogs and monkeys were challenged continuously with gamma rays at 35 r/day until death to determine the amount of radiation-induced injry remaining in conditioned animals as a reduction in mean survival time. Dogs (50%) and monkeys (8%) died from injury incurred during conditioning exposures. Thus, the comparative response (in terms of lethality) of dogs and monkeys to dose protraction by acute dose fractionation was similar to what we would expect from a single acute dose. The mean survival times for nonconditioned dogs and monkeys during continuous exposure at 35 R/day were the same (approx. 1400 h). Thus, the hematopoietic response of the two species by this method of dose protraction was not significantly different. Mean survival times of conditioned dogs and monkeys during the continuous 35-R/day gamma-ray challenge exposure were greater (significant in dogs but not in monkeys) than for their control counterparts. Thus, long-term radiation-induced injury was not measurable by this method. Conditioning doses of more than 4 times the acute LD5030 in dogs and approximately 2 times that in monkeys served only to increase both mean survival time and variance in a gamma-ray stress environment with a dose rate of 35 Rat/day

  9. Hazards to the eye lens and gonads from hard beta rays

    International Nuclear Information System (INIS)

    Considerable attention has been paid to the protection against x and γ radiation but comparatively less stress has been given to the possible hazard due to external radiation from high-energy beta rays. In order to evaluate the magnitude of this hazard, central-axis depth doses at different source-to-skin distances for 90Sr-90Y and 32P sources were measured. Isodose curves in a testicular phantom for a 90Sr-90Y source were measured. The data of Haybittle for 144Ce for 10 cm SSD has been included. From the measured data, the eye-lens epithelium dose may be as high as 51%, 21.5%, and 82%, respectively, for the three sources instead of 15% as has been conventionally assumed. The isodose curves obtained in the testicular phantom indicate that an appreciable amount of testicular tissue can be subjected to radiation exposures. The radiation hazards due to high-energy beta rays are not negligible and considerable care should be exercised while using these sources

  10. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    It has been emphasised the importance of DNA as the main target for ionizing radiation, that can induce damage by its direct action on this molecule or by an indirect effect mediated by free-radicals generated by water radiolysis. Biological effects of ionizing radiation are influenced not only by the dose but also by the dose-rate and the radiation quality. Radiation induced damage, mainly DNA single and double strand breaks, is detected by molecular sensors which in turn trigger signalling cascades leading to cell cycle arrest to allow DNA repair or programmed cell death (apoptosis). Those effects related with cell death, named deterministic, exhibits a dose-threshold below which they are not observed. Acute radiation syndrome and radiological burns are examples of this kind of effects. Other radiation induced effects, called stochastic, are the consequence of cell transformation and do not exhibit a dose-threshold. This is the case of cancer induction and hereditary effects. The aim of this presentation is briefly describe the main aspects of deterministic and stochastic effects from the point of view of radiobiology and radio pathology. (author)

  11. Absorbed dose measurements using TLDS in biological samples from beta radiation

    Directory of Open Access Journals (Sweden)

    José Eduardo Manzoli

    2006-01-01

    Full Text Available Irradiation of samples in peculiar experimental apparatus, subject to radiation spread, requires a special evaluation of absorbed dose implanted to the sample. Indirect calibration of the irradiation source, obtained in a different apparatus, and the spread, usually of very difficult theoretical evaluation, can cause very serious measurement errors, sometimes reaching 50%. In this work, the procedure for dose evaluation in an apparatus for beta irradiation of samples, usually biological ones,is presented, making use of calibration curves, obtained by irradiation in advance of thermoluminescent detectors in air, and so irradiating them in the same position of the sample. An application in blood sample irradiation is also presented.A irradiação de amostras em arranjos experimentais peculiares sujeitos a espalhamento necessita de uma determinação própria da dose absorvida que a amostra irá receber. A calibração indireta da fonte de irradiação, que ocorre em arranjo diferente, e o espalhamento, geralmente de difícil estimativa teórica, podem causar erros de medição muito elevados, não raro atingindo 50%. Neste trabalho é apresentado o procedimento para determinação da dose absorvida em um arranjo para irradiação beta de amostras, normalmente biológicas, utilizando curvas de calibração obtidas pela irradiação de dosímetros termoluminescentes no ar, e os irradiando na mesma posição das amostras. É apresentado um exemplo de aplicação para amostra irradiada de sangue.

  12. An application of the swept-current method to a DuMond type magnetic beta ray spectrometer

    International Nuclear Information System (INIS)

    The ''combination magnetic-Si(Li), swept current electron spectrometer'' method has been applied to a DuMond type magnetic beta ray spectrometer without depriving the spectrometer of the function of high resolution measurements by usual uses. Properties of the system have been examined by observing conversion lines of sup(110m)Ag and good performances of the system have been confirmed. By adopting this method, intensive sources with large area can be used and entire momentum spectra can be obtained rapidly irrespective of the existences of gamma rays and so weak conversion lines can be found more easily. For nuclei with high beta ray backgrounds, the method is not so powerful that an experiment to combine the electron-beta coincidence method with this one is now in progress. (auth.)

  13. Cytogenetic measurements of the relative biological effectiveness of tritium

    International Nuclear Information System (INIS)

    Chromosome aberrations in peripheral blood lymphocytes, which are used to estimate radiation dose biologically, were induced by tritium 1.14 times as effectively as X-rays (95% confidence limits: 0.8 - 1.5). Chromosome translocations in spermatogonia, which are one component of genetic risk, were induced by tritium 1.21 times as effectively as X-rays (95% confidence limits: 0.8 -1.9). All experimental measurements were made in CBA/H mice injected with tritiated water or exposed to X-rays at a comparable dose rate

  14. Biological Effects after Prenatal Irradiation

    International Nuclear Information System (INIS)

    A Task Group of the International Commission on Radiological Protection (ICRP) has finished a report Biological Effects after Prenatal Irradiation (Embryo and Fetus) which has been approved by the Main Commission and Will be Published. Some new important scientific data shall be discussed in this contribution. During the preimplantation period lethality of the mammalian embryo is the dominating radiation effect. However, in mouse strains with genetic predispositions it has been shown that also malformations can be caused. This effect is genetically determined and its mechanisms is different from the induction of malformations during major organogenesis. Radiation exposures during this prenatal period leads ato an increase of genomic instability of cells in the normal appearing fetuses. These radiation effects can be transmitted to the next generation. A renewed analysis of individuals with severe mental retardation after exposures during the 8th to 15th week post conception in Hiroshima and Nagasaki gives evidence that a threshold dose exists for this effect around 300 mGy. This is supported by a number of experimental animal data which have been obtained from cellular and molecular investigations during the brain development. The data show the high radiosensitivity of the developing brain but also the various compensatory mechanisms and the enormous plasticity of these processes. The radiosensitivity varies strongly during the prenatal development. The highest sensitivity is found during the early and mid fetal period which is coinciding with weeks 8-15 post conception in humans. The lowest doses causing persistent damage are in the range of 100 to 300 mGy. For intelligence quotient scores a linear dose response model provides a satisfactory fit. From the experimental data it can be concluded that the fetal stage is most sensitive to the carcinogenic effect in comparison to the other prenatal stages. Such as clear situation cannot be obtained from the

  15. Biophysical interpretation on the biological actions of radiations

    International Nuclear Information System (INIS)

    It is known that nuclear radiations such as alpha, beta, gamma, x-rays and neutron, proton and other heavy ion beams have many different actions on living cells; as killing, delaying growth, abnormal cell divisions and various genetical mutations and chromosomal aberrations. This document describes the mechanisms and kinetics of biological effects of ionizing radiation

  16. Quantitative biological imaging by ptychographic X-ray diffraction microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Giewekemeyer, Klaus; Kalbfleisch, Sebastian; Beerlink, Andre; Salditt, Tim [Institut fuer Roentgenphysik, Georg-August-Universitaet Goettingen (Germany); Thibault, Pierre; Dierolf, Martin; Pfeiffer, Franz [Department Physik (E17), Technische Universitaet Muenchen, Garching (Germany); Kewish, Cameron M. [Paul Scherrer Institut, Villigen PSI (Switzerland)

    2010-07-01

    Mesoscopic structures with specific functions are abundant in many cellular systems and have been well characterized by electron microscopy in the past. However, the quantitative study of the three-dimensional structure and density of subcellular components remains a difficult problem. In this contribution we show how these limitations could be overcome in the future by the application of recently introduced and now rapidly evolving coherent X-ray imaging techniques for quantitative biological imaging on the nanoscale. More specifically, we report on a recent scanning (ptychographic) diffraction experiment on unstained and unsliced freeze-dried cells of the bacterium Deinococcus radiourans using only a pinhole as beam defining optical element. As a result quantitative density projections well below optical resolution have been achieved.

  17. An imidazoline compound completely counteracts interleukin-1[beta] toxic effects to rat pancreatic islet [beta] cells

    DEFF Research Database (Denmark)

    Papaccio, Gianpaolo; Nicoletti, Ferdinando; Pisanti, Francesco A; Galdieri, Michela; Bendtzen, Klaus

    2002-01-01

    In vitro studies have demonstrated that interleukin (IL)-1beta decreases insulin and DNA contents in pancreatic islet beta cells, causing structural damage, that it is toxic to cultured human islet beta cells and that it is able to induce apoptosis in these cells....

  18. Biological markers of amyloid beta-related mechanisms in Alzheimer's disease.

    LENUS (Irish Health Repository)

    Hampel, Harald

    2010-06-01

    Recent research progress has given detailed knowledge on the molecular pathogenesis of Alzheimer\\'s disease (AD), which has been translated into an intense, ongoing development of disease-modifying treatments. Most new drug candidates are targeted on inhibiting amyloid beta (Abeta) production and aggregation. In drug development, it is important to co-develop biomarkers for Abeta-related mechanisms to enable early diagnosis and patient stratification in clinical trials, and to serve as tools to identify and monitor the biochemical effect of the drug directly in patients. Biomarkers are also requested by regulatory authorities to serve as safety measurements. Molecular aberrations in the AD brain are reflected in the cerebrospinal fluid (CSF). Core CSF biomarkers include Abeta isoforms (Abeta40\\/Abeta42), soluble APP isoforms, Abeta oligomers and beta-site APP-cleaving enzyme 1 (BACE1). This article reviews recent research advances on core candidate CSF and plasma Abeta-related biomarkers, and gives a conceptual review on how to implement biomarkers in clinical trials in AD.

  19. Biological markers of amyloid beta-related mechanisms in Alzheimer's disease.

    LENUS (Irish Health Repository)

    Hampel, Harald

    2012-02-01

    Recent research progress has given detailed knowledge on the molecular pathogenesis of Alzheimer\\'s disease (AD), which has been translated into an intense, ongoing development of disease-modifying treatments. Most new drug candidates are targeted on inhibiting amyloid beta (Abeta) production and aggregation. In drug development, it is important to co-develop biomarkers for Abeta-related mechanisms to enable early diagnosis and patient stratification in clinical trials, and to serve as tools to identify and monitor the biochemical effect of the drug directly in patients. Biomarkers are also requested by regulatory authorities to serve as safety measurements. Molecular aberrations in the AD brain are reflected in the cerebrospinal fluid (CSF). Core CSF biomarkers include Abeta isoforms (Abeta40\\/Abeta42), soluble APP isoforms, Abeta oligomers and beta-site APP-cleaving enzyme 1 (BACE1). This article reviews recent research advances on core candidate CSF and plasma Abeta-related biomarkers, and gives a conceptual review on how to implement biomarkers in clinical trials in AD.

  20. Dosimetry and biological effects of fast neutrons

    International Nuclear Information System (INIS)

    This thesis contains studies on two types of cellular damage: cell reproductive death and chromosome aberrations induced by irradiation with X rays, gamma rays and fast neutrons of different energies. A prerequisite for the performance of radiobiological experiments is the determination of the absorbed dose with a sufficient degree of accuracy and precision. Basic concepts of energy deposition by ionizing radiation and practical aspects of neutron dosimetry for biomedical purposes are discussed. Information on the relative neutron sensitivity of GM counters and on the effective point of measurement of ionization chambers for dosimetry of neutron and photon beams under free-in-air conditions and inside phantoms which are used to simulate the biological objects is presented. Different methods for neutron dosimetry are compared and the experimental techniques used for the investigations of cell reproductive death and chromosome aberrations induced by ionizing radiation of different qualities are presented. Dose-effect relations for induction cell inactivation and chromsome aberrations in three cultured cell lines for different radiation qualities are presented. (Auth.)

  1. Uniform Catalytic Site in Sn-beta Zeolite Determined using X-ray Absorption Fine Structure

    Energy Technology Data Exchange (ETDEWEB)

    Bare,S.; Kelly, S.; Sinkler, W.; Low, J.; Modica, F.; Valencia, S.; Corma, A.; Nemeth, L.

    2005-01-01

    The Sn silicate zeolite, Sn-{beta}, has been shown to be an efficient, selective heterogeneous catalyst for Baeyer-Villiger oxidations. Using primarily a multishell fit to extended X-ray absorption fine structure (EXAFS) data, we show that the Sn does not randomly insert into the {beta}-zeolite structure but rather occupies identical, specific, crystallographic sites. These sites are the T5/T6 sites in the six-membered rings. Moreover, the Sn is substituted in pairs on opposite sides of these six-membered rings. We believe that it is the specific, uniform crystallographic location of the Sn in the crystal structure that leads to sites with uniform catalytic activity, and consequently to the high chemical selectivity demonstrated for this catalyst. This manifests itself in the almost enzyme-like selectivity of this catalyst in Baeyer-Villiger oxidations. This uniform site distribution of the Sn suggests that there is likely a symbiotic relationship between the structure-directing agent in the zeolite synthesis and the Sn heteroatoms during the framework formation.

  2. Beta effects on rf-driven current profile and driving efficiency in reversed field pinch plasma

    International Nuclear Information System (INIS)

    The current density profile in reversed field pinch (RFP) plasma is controlled by rf current drive using a single-ray fast magnetosonic wave (FMW; f - 10fDC, fDC is deuteron cyclotron frequency). This paper reports more detailed beta effects on both the current density profile and the current driving efficiency with a fixed wave parameters. Any increase of beta value due to either increase of electron temperature Te0(0) or density ne0(0) makes the force-free current distribution more flat in the inner region. Increasing Te0(0) at a fixed higher beta value enhances the rf-driven current and the magnetic shear, but a positive gradient of force-free current which makes m=1 tearing mode unstable. There is an optimum Te0(0) value which maximizes the region of constant force-free current not having its positive gradient, although its positive gradient can be also controlled by adjusting wave parameters. Then the global current driving efficiency is lower rather than that for the lower beta plasma. (author)

  3. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    The efficient dose of ionizing radiation (I.R.), expressed in sievert is a weighting of the deposited energy (absorbed dose in grays) by factors that take into account the radiation hazard and tissues radiosensitivity. it is useful in radiation protection because it allows to add exposures to ionizing radiation of different nature. for low doses, it has no probabilistic value. The determinist effects of ionizing radiation are observed from thresholds of several hundred of milli sievert. The seriousness grows with the dose. The whole-body doses exceeding 8 Sv are always lethal. The radio-induced cancers are observed only for doses exceeding 100 to 200 mSv for adults, delivered at a self important dose rate. Their seriousness does not depend on the dose. Their appear fortuity (stochastic effect) with a various individual susceptibility, genetically determined. The number of eventual radio-induced cancers coming from the exposure of a high number of persons to low dose of ionizing radiation (<100 mSv) cannot be evaluated with a linear without threshold model. these models, however usually used, do not take into account the biological reality of cell defense mechanisms, tissues or whole body defense mechanisms, these one being different against low or high doses of ionizing radiation. Against low doses, the preponderant mechanism is the elimination of potentially dangerous damaged cells. Against high doses, the repair of damaged cells is imperative to preserve the tissue functions. It can lead to DNA repair errors (radio-induced mutations) and canceration. The radio-induced congenital malformations are effects with threshold. The radio-induced carcinogenesis in utero is a stochastic effect. The radio-induced hereditary congenital malformations have never been highlighted for man. (N.C.)

  4. First identification of. gamma. rays in the. beta. /sup +//EC decay of sup(104,105)Sn

    Energy Technology Data Exchange (ETDEWEB)

    Deneffe, K.; Coenen, E.; Huyse, M.; Duppen, P. van (LISOL, Leuven (Belgium). Inst. voor Kern- en Stralingsfysika); Vanhorenbeeck, J. (Universite Libre de Bruxelles (Belgium)); Marmol, P. del; Fettweis, P. (Centre d' Etude de l' Energie Nucleaire, Mol (Belgium))

    1985-03-01

    The ..beta../sup +//EC decay of mass-separated /sup 104/Sn and /sup 105/Sn isotopes was studied by x-ray and ..gamma..-ray singles, as well as by x-..gamma.. and ..gamma..-..gamma.. coincidences. Sources were produced in the reactions /sup 92/Mo (/sup 20/Ne, ypxn). The nucleus /sub 50//sup 104/Sn with Tsub(1/2 = 23 +- 2 s was identified. A partial decay scheme of /sup 105/Sn is proposed.

  5. Ornithogalum virens as a plant assay for beta and gamma radiation effects

    International Nuclear Information System (INIS)

    The purpose of this study was to determine if the monocotyledonous angiosperm, Ornithogalum virens (Quintanilha and Cabral, 1947), could be used in such a biological assay system. After exposing O. virens plants to acute (60Co) and chronic (137Cs) gamma radiation and internal beta radiation (32P), lethality (LD50, LD100), growth inhibition, and chromosome aberrations were investigated. The LD50 and LD100 for acute gamma radiation were estimated to be between 0.91 to 1.8 krad and less than 3.6 krad, respectively. Though growth inhibition and abnormal growth were observed in the acute and chronic gamma radiation studies, the changes in the growth of the plants were so variable that these parameters were found to be unreliable measures of radiation effects. Chromosome aberrations were a more reliable measure of radiation damage because linear relationships between total aberrations and dose were found for both gamma and beta radiation

  6. Biological effects of heavy ion and X-ray irradiation on lung cancer cells A549%重离子与X射线照射肺癌细胞A549的生物学效应比较

    Institute of Scientific and Technical Information of China (English)

    杨立娜; 冉俊涛; 张红; 刘圆圆; 孙超; 张秋宁; 王新宇; 王小虎

    2014-01-01

    Objective To compare the effects of carbon heavy ion and X-ray irradiation on survival fraction,cell cycle,cell apoptosis and expression of DNA-PKcs of A549 lung cancer cells.Methods A549 cells were irradiated by carbon heavy ion and X-ray.Cell survival fraction,cell cycle and apoptosis were analyzed by clonogenic formation assay,flow cytometry and Hoechst 33258 staining,respectively.Real time-PCR was performed to detect the expressions of DNA-PKcs and H2AX mRNA.Results Lower cell survival fraction,more G2/M phase arrest and higher apoptosis rate were detected in the A549 cells exposed to carbon heavy ion than X-ray(t =4.77,14.53,14.54,P < 0.05).Expression of DNA-PKcs was up-regulated after irradiation to carbon heavy ion and X-ray(t =10.91,5.05,P < 0.05).Conclusions Both heavy ion and X-ray irradiations enhance the expression of DNA-PKcs,induce apoptosis through regulating cell cycle arrest,and hence reduce survival of A549 cells.Heavy ion irradiation shows more stronger biological effects than X-ray irradiation.%目的 比较碳重离子与X射线对肺癌细胞的生物学效应.方法 对A549细胞分别进行碳重离子和X射线照射,通过克隆形成实验检测照射后细胞存活情况;流式细胞术检测细胞周期分布;通过Hoechst 33258荧光染料对照射后固定的细胞进行染色,计算凋亡率;采用实时荧光定量PCR方法检测照射后48 h细胞内DNA依赖性蛋白激酶催化亚单位(DNA-PKcs)和H2AX的mRNA表达水平.结果 细胞存活曲线显示,碳重离子造成的细胞存活分数远低于X射线,并将细胞周期阻滞于G2/M期(t=4.77、14.53、14.54,P<0.05),导致大部分细胞进入凋亡途径.碳重离子与X射线辐照后DNA-PKcs的表达上调(t=10.91、5.05,P<0.05).结论 碳重离子照射对肺癌细胞造成生物学效应远高于X射线.

  7. Environmental Effects of Gamma Ray Bursts

    International Nuclear Information System (INIS)

    Gamma rays bursts, coming from very massive stars, are the most powerful explosions in our Universe. Some authors have linked them to some of the climatic changes and consequent biological mass extinctions of the Phanerozoic eon. However, the consequences of their direct impact on primitive Earth, is today a hot topic of debate. On the other hand, it is usually assumed that they were more common in earlier stages of our galaxy. So it is important to evaluate its potential effects on terrestrial paleoenvironments. We outline some simple models to estimate their influence mainly on the primordial atmospheric chemistry of Earth and on the climate in general. To do that, we consider different scenarios where the atmospheric composition diverges substantially from the atmosphere today, and compute the evolution of principal chemical species under the intense radiational stress of a gamma ray burst. Furthermore, the possible impact on the isotopic composition, geochemistry and the biosphere are mentioned in general way

  8. The CRRES/SPACERAD heavy ion model of the environment (CHIME) for cosmic ray and solar particle effects on electronic and biological systems in space

    International Nuclear Information System (INIS)

    Accurate estimates of the frequency of single event effects require accurate models of the fluxes of heavy ions which cause them. These flux models must account for the multifarious temporal variations of ion flux intensity, and their significant energy- and species-dependencies. The authors present a new time-dependent model of the interplanetary heavy ion environment and a new set of software based on this model to calculate energy deposit (LET) spectra and resulting single event upset rates

  9. Paradigm Shift in Radiation Biology/Radiation Oncology-Exploitation of the "H₂O₂ Effect" for Radiotherapy Using Low-LET (Linear Energy Transfer) Radiation such as X-rays and High-Energy Electrons.

    Science.gov (United States)

    Ogawa, Yasuhiro

    2016-01-01

    Most radiation biologists/radiation oncologists have long accepted the concept that the biologic effects of radiation principally involve damage to deoxyribonucleic acid (DNA), which is the critical target, as described in "Radiobiology for the Radiologist", by E.J. Hall and A.J. Giaccia [1]. Although the concepts of direct and indirect effects of radiation are fully applicable to low-LET (linear energy transfer) radioresistant tumor cells/normal tissues such as osteosarcoma cells and chondrocytes, it is believed that radiation-associated damage to DNA does not play a major role in the mechanism of cell death in low-LET radiosensitive tumors/normal tissues such as malignant lymphoma cells and lymphocytes. Hall and Giaccia describe lymphocytes as very radiosensitive, based largely on apoptosis subsequent to irradiation. As described in this review, apoptosis of lymphocytes and lymphoma cells is actually induced by the "hydrogen peroxide (H₂O₂) effect", which I propose in this review article for the first time. The mechanism of lymphocyte death via the H₂O₂ effect represents an ideal model to develop the enhancement method of radiosensitivity for radiation therapy of malignant neoplasms. In terms of imitating the high radiosensitivity of lymphocytes, osteosarcoma cells (representative of low-LET radioresistant cells) might be the ideal model for indicating the conversion of cells from radioresistant to radiosensitive utilizing the H₂O₂ effect. External beam radiation such as X-rays and high-energy electrons for use in modern radiotherapy are generally produced using a linear accelerator. We theorized that when tumors are irradiated in the presence of H₂O₂, the activities of anti-oxidative enzymes such as peroxidases and catalase are blocked and oxygen molecules are produced at the same time via the H₂O₂ effect, resulting in oxidative damage to low-LET radioresistant tumor cells, thereby rendering them highly sensitive to irradiation. In this

  10. The Effect of Cancellation in Neutrinoless Double Beta Decay

    CERN Document Server

    Pascoli, Silvia; Wong, Steven

    2013-01-01

    In light of recent experimental results, we carefully analyze the effects of interference in neutrinoless double beta decay, when more than one mechanism is operative. We assume a complete cancellation is at work for $^{136}\\rm{Xe}$, and find its implications on the half-life of other isotopes, such as $^{76}\\rm{Ge}$. For definiteness, we consider the role of light and heavy sterile neutrinos. In this case, the effective Majorana mass parameter can be redefined to take into account all contributions and its value gets suppressed. Hence, larger values of neutrino masses are required for the same half-life. The canonical light neutrino contribution can not saturate the present limits of half-lives or the positive claim of observation of neutrinoless double beta decay, once the stringent bounds from cosmology are taken into account. For the case of cancellation, where all the sterile neutrinos are heavy, the tension between the results from neutrinoless double beta decay and cosmology becomes more severe. We sho...

  11. Guidelines for the calibration of low energy photon sources at beta-ray brachytherapy sources

    International Nuclear Information System (INIS)

    Kerma Rate. In this document the latter recommendation is adopted. Both of the quantities give the same numerical value for the source strength and differ only in the units they are expressed. The recommended dose calculation method is discussed further in the text. Sealed beta-ray sources for brachytherapy treatments have been in use for few decades already. An example is application of 90Sr/90Y planar sources for ophthalmic brachytherapy treatments. For these types of treatments, a precise dose distribution within the eye globe is needed. Modern diagnostic techniques permit the determination of all volumes of interest in the eye, i.e. tumor and critical structures such as optic disc and iris with a high precision. It is therefore of importance to optimize the treatment by limiting the dose to these critical structures. A relatively new and rapidly developing field in brachytherapy is the use of beta-ray sources for prevention of restenosis, i.e. re-closing of artery, following coronary and peripheral artery interventional procedures such as angioplasty, atherectomy and stent implantation. The dosimetry of beta-ray sources for therapeutic applications is particularly difficult due to the short distances involved, being at the millimeter range, and the high dose gradients at such short distances. Further difficulties are caused by the non-uniform distribution of activity in the source itself, causing a highly irregular dose distribution. The aim of this report is to recommend methods for calibration of low energy photon sources and beta-ray sources used in brachytherapy treatments and to propose suitable detectors for this purpose. Dose calculation methods are given both for the photon sources and beta-ray sources covered in this report. The present report has been developed in close collaboration with the ICRU Report Committee on this subject. The ICRU is planning to publish a report on the calibration of the type of sources discussed here. The present report is to a

  12. Biological control of Polymyxa betae, fungal vector of rhizomania disease of sugar beets in greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Naraghi Laleh

    2014-07-01

    Full Text Available Rhizomania is one of the most important diseases of sugar beet around the world – including in Iran. The disease causes a severe decrease in sugar yield and is a limiting factor in sugar beet cultivation. Control of the disease is very difficult due to the long-term survival of its fungal vector (Polymyxa betae in the soil. In this study, we investigated the effects of antagonistic fungal isolates on the population of the resting structure (cystosorus of P. betae, under greenhouse conditions. Antagonistic fungi, including Trichoderma harzianum and Talaromyces flavus, were isolated from soil samples collected from sugar beet infested fields in the Semnan Province of Iran. In the next step, their inocula were prepared through reproduction on rice bran. For evaluation of the efficacy of antagonists in greenhouse conditions, a split plot trial was conducted and performed. The main factor was three different methods of application of T. flavus as the soil treatment, seed treatment, and a combination of both methods. The sub-factor was the use of different fungal isolates. To determine the cystosorus population of the fungal vector, seedling roots in all treatments were stained with lactic acid and fuchsine (lactofushine, 60 days after sowing. The number of cystosorus in one gram of root was counted using a light microscope and hemocytometer. At the end of the study, average root weight in different treatments was also measured to select and introduce the best treatments in regard to their effects on root weight. According to the results, the number of cystosorus in 1 g of root was different in various treatments and those treatments containing TF-Su-M-1, TF-Su-M-2, TH-Su-M-1, and TH-Su-M-2 used as a soil application method were more effective in the reduction of the cystosorus population and root weight increase. Among the above-mentioned treatments, maximum reduction of cystosori population and the increase in root weight were observed in TH

  13. Detrimental effects of beta-blockers in COPD - A concern for nonselective beta-blockers

    NARCIS (Netherlands)

    van der Woude, HJ; Zaagsma, J; Postma, DS; Winter, TH; van Hulst, M; Aalbers, R

    2005-01-01

    Introduction: beta-Blockers are known to worsen FEV1 and airway hyperresponsiveness (AHR) in patients with asthma. Both characteristics determine the outcome of COPD, a disease with frequent cardiac comorbidity requiring beta-blocker treatment. Design: A double-blind, placebo-controlled, randomized,

  14. Biological radiation dose from secondary particles in a Milky Way gamma ray burst

    CERN Document Server

    Atri, Dimitra; Karam, Andrew

    2013-01-01

    Gamma ray bursts (GBRs) are a class of highly energetic explosions emitting radiation in a very short timescale of a few seconds and with a very narrow opening angle. Although, all GRBs observed so far are extragalactic in origin, there is a high probability of a GRB of galactic origin beaming towards the Earth in the past ~ 0.5 Gyr. Such an intense burst of gamma rays would ionize the atmosphere and deplete the ozone layer. With depleted ozone, there will be an increased flux of solar UVB on the Earth\\~Os surface with harmful biological effects. In addition to the atmospheric damage, secondary particles produced by gamma ray-induced showers will reach the surface. Amongst all secondary particles, muons dominate the ground-level secondary particle flux (99% of the total number of particles) and are potentially of biological significance. Using the Monte Carlo simulation code CORSIKA, we modeled the air showers produced by gamma ray primaries up to 100 GeV. We found that the number of muons produced by hypothe...

  15. Biological radiation effects of Radon in Drosophila

    International Nuclear Information System (INIS)

    In order to contribute to the knowledge on the effects of radon and its decay products, the aim of this investigation is to study the biological effects of radon using Drosophila melanogaster throught the somatic mutation and recombination test (SMART) and the analysis of some adaptative factors exposing larvaes to controlled radon atmosphers, considering that this insect could be used as biological monitor. Using the somatic mutation test a mutagenic effect was observed proportional to radon concentration, into an interval of 1 ± 0.3 to 111 ± 7.4 KBq/m3 equivalent to doses under 0.0106 Gy. The correlation analysis gives a linear (r=0.80) relationship with a positive slope of 0.2217. The same happens when gamma rays are used in the interval of 1 to 20 Gy, given a linear dose-dependent effect (r=0.878) is obtained; nevetheless the slop is smaller (m=0.003) than for radon. Analysing the results of adaptative factors of the nine exposed generations, it was found that probably radon exposition induced dominant lethals during gametogenesis or/and a selection of the more component gamets of the treated individuals in larval state. It was reflected in the significant decrease on fecundity of the generation exposed. Nevertheless the laying eggs had an increase in egg-to-adult viability and the develop velocity was higher than in control for 3 KBq/m3, this suggest that radon concentrations used were able to induce repair mechanisms. These data agree with the Hormesis hypothesis that says: low doses have positive effects on health. It was not possible to obtain a dose-effect relationship except with the develop velocity where it was found a dose-effect inverse proportion. In conclusion, Drosophila melanogaster could be a good system to obtain in vivo damaged induction concentration dependent of radon and its decay products, as well as to study the effects in an exposed population by the analysis of adaptative factors. (Author)

  16. Beta decay of the fission product 125Sb and a new complete evaluation of absolute gamma ray transition intensities

    Science.gov (United States)

    Rajput, M. U.; Ali, N.; Hussain, S.; Mujahid, S. A.; MacMahon, D.

    2012-04-01

    The radionuclide 125Sb is a long-lived fission product, which decays to 125Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

  17. Detection of Aspergillus Galactomannan Antigenemia To Determine Biological and Clinical Implications of Beta-Lactam Treatments

    OpenAIRE

    Bart-Delabesse, Emmanuelle; Basile, Maria; Al Jijakli, Ahmad; Souville, Didier; Gay, Frédérick; Philippe, Bruno; Bossi, Philippe; Danis, Martin; Vernant, Jean-Paul; Datry, Annick

    2005-01-01

    Detection of Aspergillus galactomannan (GM) in serum with the Platelia Aspergillus enzyme immunoassay (EIA) is useful for diagnosing invasive aspergillosis. From May 2003 to November 2004, 65 patients who did not develop aspergillosis had at least two positive sera while receiving a beta-lactam treatment (GM index [GMI], ≥0.5). Of the 69 treatment episodes scored, 41 consisted of a beta-lactam other than piperacillin-tazobactam (n = 29), namely, amoxicillin-clavulanate (n = 25), amoxicillin (...

  18. Biological effectiveness of antiproton annihilation

    DEFF Research Database (Denmark)

    Holzscheiter, M.H.; Agazaryan, N.; Bassler, Niels;

    2004-01-01

    We describe an experiment designed to determine whether or not the densely ionizing particles emanating from the annihilation of antiprotons produce an increase in ‘‘biological dose’’ in the vicinity of the narrow Bragg peak for antiprotons compared to protons. This experiment is the first direct...

  19. URODYNAMIC EFFECTS OF BETA-ADRENOBLOCKERS: NEBIVOLOL ADVANTAGES

    Directory of Open Access Journals (Sweden)

    M. P. Savenkov

    2016-01-01

    Full Text Available Aim. To compare urodynamic effects of beta-blockers with different selectivity (propranolol, metoprolol, nebivolol in patients with arterial hypertension (HT and concomitant benign prostatic hyperplasia (BPH.Material and methods. 32 patients (aged 67,5 y.o. in average with HT of 1-2 stages were involved in the study. All patients had BPH (prostate volume >40 sm3 , increase of residual urine volume with moderate or severe low urinary tract symptoms (IPSS 8-25 and reduction of maximum urine flow rate to 5-13 ml/s. The urodynamic effect of beta-blockers was estimated by changes of urination frequency and uroflowmetry indices after single taking and 14-day therapy.Results. Propranolol and metoprolol led to aggravation of urination disorders. Nebivolol resulted in soft urodilating and urostimulating effects. It led to urination improvement and reduced a risk of urodynamic disorders.Conclusion. Urodynamic effects of cardiovascular drugs should be considered by practitioners especially in treatment of elderly patients.

  20. Dual energy x-ray absorptiometry (DEXA) in the assessment of liver iron in patients with beta thalassaemia major

    International Nuclear Information System (INIS)

    Full text: Beta thalassaemia major is a condition in which anaemia from abnormal haemoglobin production causes bone marrow expansion and frequently reduced bone mineral density. These patients have a chronic requirement for transfusion which results in tissue iron overload which may cause organ damage. Increased X-ray attenuation in the liver was noted in patients undergoing whole body DEXA for the assessment of bone density and it was assumed that this was related to liver iron stores. The aim of this study was to determine if useful information about liver iron could be obtained from these studies. Method: Using a Lunar DPXL, whole body scanning was performed in 16 patients (eight male) age 19-32 with Beta Thalassaemia. As well as calculating indices of total body composition, regions of interest were placed over the visualised liver. The 'bone mineral content' (BMC),g and bone mineral density (BMD),g/cm2 were calculated over the liver regions, with the assumption that the calculation related to mineral in the region of interest. The results were compared with the serum ferritin as an indirect measure of body iron stores. Results showed a highly significant correlation (r=0.85) between 'BMD' in the liver region and ferritin. Conclusion: Despite the known difficulties with equating iron stores and ferritin, and possible confounders on liver density, such as fibrosis, the high correlation suggests that DEXA may have a place in the assessment of iron deposition, and be more cost effective than other technologies such as MRI and CT. Prospective studies with invasive measurements of liver iron will be needed to determine this. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  1. Calculation of beta-ray dose distributions from ophthalmic applicators and comparison with measurements in a model eye

    International Nuclear Information System (INIS)

    Dose distributions throughout the eye, from three types of beta-ray ophthalmic applicators, were calculated using the EGS4, ACCEPT 3.0, and other Monte Carlo codes. The applicators were those for which doses were measured in a recent international intercomparison [Med. Phys. 28, 1373 (2001)], planar applicators of 106Ru-106Rh and 90Sr-90Y and a concave 106Ru-106Rh applicator. The main purpose was to compare the results of the various codes with average experimental values. For the planar applicators, calculated and measured doses on the source axis agreed within the experimental errors (106Ru-106Rh and 5 mm for 90Sr-90Y. At greater distances the measured values are larger than those calculated. For the concave 106Ru-106Rh applicator, there was poor agreement among available calculations and only those calculated by ACCEPT 3.0 agreed with measured values. In the past, attempts have been made to derive such dose distributions simply, by integrating the appropriate point-source dose function over the source. Here, we investigated the accuracy of this procedure for encapsulated sources, by comparing such results with values calculated by Monte Carlo. An attempt was made to allow for the effects of the silver source window but no corrections were made for scattering from the source backing. In these circumstances, at 6 mm depth, the difference in the results of the two calculations was 14%-18% for a planar 106Ru-106Rh applicator and up to 30% for the concave applicator. It becomes worse at greater depths. These errors are probably caused mainly by differences between the spectrum of beta particles transmitted by the silver window and those transmitted by a thickness of water having the same attenuation properties

  2. Gas density and X-ray surface brightness profiles of clusters of galaxies from dark matter halo potentials beyond the isothermal beta model

    CERN Document Server

    Suto, Y; Makino, N; Suto, Yasushi; Sasaki, Shin; Makino, Nobuyoshi

    1998-01-01

    We describe a theoretical framework to compute the cluster gas distribution in hydrostatic equilibrium embedded in a class of spherical dark matter halo potentials. Unlike the conventional isothermal $\\beta$-model, the present method provides a physical basis to directly probe the shape of dark matter halo from the observed X-ray surface brightness and temperature profiles of clusters of galaxies. Specifically, we examine the extent to which the resulting gas density and X-ray surface brightness profiles are sensitive to the inner slope of the dark matter halo density and other more realistic effects including the self-gravity of the gas and the polytropic equation of state. We also discuss a practical strategy to apply the present methodology to the actual cluster profiles from future X-ray observations.

  3. Ultra-low gamma-ray measurement system for neutrinoless double beta decay

    International Nuclear Information System (INIS)

    An experiment for the detection of 0νβ+/EC and 0νEC/EC in 92Mo nuclei has been carried out with a scintillating crystal, CaMoO4, in coincidence with the HPGe detector. We study the background events inside the event selection window for 0ν β+/EC decays of CaMoO4 detector. For 51.2 days of data taking period, we didn't observe any event in the neutrinoless EC/EC decay event window. The 92Mo 0νβ+/EC decay half-life limit was set to 0.61×1020 years with a 90% confidence by method of Feldman and Cousins. This ultra-low gamma ray measurement utilizing coincidence technique can be used for the resonant EC/EC decay process of some nuclei which is potentially important for neutrinoless double beta decay process. - Highlights: • 0νββ experiment is the only practical way to study the nature of neutrino mass. • We performed a 0νββ experiment with a HPGe detector and a CaMoO4 crystal. • The limit of the half-life of the 0νβ+/EC is 0.61×1020 years at 90% CL

  4. A new method for characterizing beta-ray ophthalmic applicator sources

    International Nuclear Information System (INIS)

    A technique is described which enables one to obtain detailed dose characteristics of 90Sr beta-ray ophthalmic applicators. A radiochromic radiation detector which is a solid-state solution of hexahydroxyethyl pararosaniline cyanide in a nylon polymer (i.e., thin foil), has been used to determine the surface dose rate and dose distribution of these sources. The detectors are rugged, easily handled, have an equivalent response (optical density per unit absorbed dose) to photons and electrons, and produce high-resolution images. They have been found useful for this application due to the high surface dose rates [0.10-1.0 Gy (H2O)/s] and their low sensitivity (approximately 10(4) Gy for an optical density of 1.0). The foils have been evaluated on a He-Ne scanning laser densitometer with a resolution of 0.3 mum. Comparison with NIST (formerly NBS) extrapolation ionization chamber measurements indicates surface dose-rate agreement within 6%. Spectral dosimetric characteristics are presented and discussed

  5. Estimation of beta-ray skin dose from exposure to fission fallout from the Hiroshima atomic bomb

    International Nuclear Information System (INIS)

    Beta-ray skin dose due to the fission fallout from the Hiroshima atomic bomb is potentially related to the epilation in the black rain area. The absorbed dose to the skin from beta-rays emitted by fission fallout has been estimated for an initial 137Cs deposition of 1 kBq m-2 on the ground at 0.5 h after the explosion. The estimated skin dose takes into account both external exposure from fission fallout radionuclides uniformly distributed in 1 mm of soil on the surface of the ground and from a 26 μm thickness of contaminated soil on the skin, using the Monte Carlo radiation transport code MCNP-4C. The cumulative skin dose for 1 month after the explosion is taken as the representative value. The estimated skin dose for an initial 137Cs deposition of 1 kBq m-2 was determined to be about 500 mSv. (authors)

  6. Total absorption γ-ray spectroscopy of beta delayed neutron emitters

    Science.gov (United States)

    Valencia, E.; Algora, A.; Tain, J. L.; Rice, S.; Agramunt, J.; Zakari-Issoufou, A.-A.; Porta, A.; Fallot, M.; Jordan, M. D.; Molina, F.; Estevez, E.; Bowry, M.; Bui, V. M.; Caballero-Folch, R.; Cano-Ott, D.; Eloma, V.; Eronen, T.; Garcia, A.; Gomez-Hornillos, M. B.; Gorlychev, V.; Hakala, J.; Jokinen, A.; Kondev, F. G.; Martinez, T.; Moore, I.; Rissanen, J.; Ńystö, J.; Penttilä, H.; Kankainen, A.; Rubio, B.; Gelletly, W.; Perez, A.; Podolyak, Zs.; Regan, P. H.; Farrelly, G. F.; Weber, C.; Mendoza, E.; Igisol People

    2013-06-01

    Preliminary results of the data analysis of the beta decay of 94Rb using a novel - segmented- total absorption spectrometer are shown in this contribution. This result is part of a systematic study of important contributors to the decay heat problem in nuclear reactors. In this particular case the goal is to determine the beta intensity distribution below the neutron separation energy and the gamma/beta competition above.

  7. Use of studies with laboratory animals to assess the potential early health effects of combined internal alpha and beta irradiation

    International Nuclear Information System (INIS)

    The potential health impacts of radionuclides released in nuclear accidents are of major concern to the public and to regulatory and other governmental agencies. One mode of potential exposure is by inhalation of airborne radionuclides, which could lead to combined internal irradiation by high (alpha) and low (beta) linear energy transfer (LET) radiations. Epidemiological data for health effects of human inhalation exposure are too limited to derive reliable estimates of risks of potential health effects. However, results of studies in which beagle dogs were exposed by inhalation to insoluble radioactive aerosols can be used to estimate expected effects in humans. Data for mortality from radiation pneumonitis and pulmonary fibrosis caused by internal irradiation of dog lungs by alpha or beta radiations are used to derive the relative biological effectiveness (RBE) of alpha irradiation compared to beta irradiation; predict the expected combined effects of alpha and beta irradiation of dog lungs; and extrapolate the results to humans. The extrapolation to humans assumed that, for similar ages at exposure, dog and human lungs have similar sensitivities to lung irradiation. Results of theoretical calculations related to mortality from early effects indicated that the synergistic effects of high- and low-LET radiations should depend on the percentages of the total dose contributed by high- and low-LET radiations, and for very low or very high doses, synergistic effects should be negligible. 23 refs., 8 figs

  8. Terrestrial Effects of High Energy Cosmic Rays

    Science.gov (United States)

    Atri, Dimitra

    2011-01-01

    On geological timescales, the Earth is likely to be exposed to an increased flux of high energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma ray bursts or by galactic shocks. These high-energy particles strike the Earth's atmosphere initiating an extensive air shower. As the air shower propagates deeper, it ionizes the atmosphere by producing charged secondary particles. Increased ionization could lead to changes in atmospheric chemistry, resulting in ozone depletion. This could increase the flux of solar UVB radiation at the surface, which is potentially harmful to living organisms. Increased ionization affects the global electrical circuit can could possibly enhance the low-altitude cloud formation rate. Secondary particles such as muons and thermal neutrons produced as a result of nuclear interactions are able to reach the ground, enhancing the biological radiation dose. The muon flux dominates radiation dose from cosmic rays causing DNA damage and increase in the mutation rates, which can have serious biological implications for terrestrial and sub-terrestrial life. This radiation dose is an important constraint on the habitability of a planet. Using CORSIKA, we perform massive computer simulations and construct lookup tables from 10 GeV - 1 PeV primaries (1 PeV - 0.1 ZeV in progress), which can be used to quantify these effects. These tables are freely available to the community and can be used for other studies, not necessarily relevant to Astrobiology. We use these tables to study the terrestrial implications of galactic shock generated by the infall of our galaxy toward the Virgo cluster. This could be a possible mechanism explaining the observed periodicity in biodiversity in paleobiology databases.

  9. Therapeutic effect of beta radiation on onychomycosis: An innovative treatment

    International Nuclear Information System (INIS)

    Full text: Onychomycosis is the most frequent cause of nail disease and the most prevalent type of dermatophytosis in Bangladesh. The humid and warm climate of this tropical country is congenial for the growth of fungi. Therapeutic limitations of conventional antimycotic agents in respect of low cure rates, high relapse rate, inherent side effects, long duration of treatment and high cost in treating onychomycosis have provided clear incentives to explore alternative forms of treatment procedure. The objectives of the present thesis work were: (i) To use beta radiation as a curative therapy for Onychomycosis, optimisation of its dosages and to promote an innovative clinical development in the field of therapeutic application of nuclear medicine; (ii) To assess the efficacy of beta radiation either alone or in combination with conventional antifungal therapy; and (iii) To reduce the duration of drug exposure and cost of treatment for onychomycosis. This is a PhD research work under the University of Dhaka and was sponsored by the Ministry of Science and Information and Communication Technology, Government of the people's republic of Bangladesh. This study is an open, randomised and controlled trial to verify the efficacy of beta radiation in patients with onychomycosis. Using the appropriate statistical formula, sample size of the study population was determined and in each group 92 patients were assigned. With an assumption of patients drop out and for better statistical analysis, a total of 330 patients, who fulfilled the inclusion criterion having diagnosed to have onychomycosis clinically and mycological were randomly allocated to enter in therapeutic regimen. Study population was randomised in three groups. Group A (n =110) received griseofulvin orally 500 mg once daily for 12-16 weeks; Group B (n=110) received beta radiation, 500 rads bi-weekly for 3 weeks (total 2500 rads); and Group C (n=110) received combined beta radiation (total 2500 rads in 3 weeks) and

  10. Doses and biological effect of ionizing radiation

    International Nuclear Information System (INIS)

    Basic values and their symbols as well as units of physical dosimetry are given. The most important information about biological radiation effects is presented. Polish radiation protection standards are cited. (A.S.)

  11. Cytokines and beta-cell biology: from concept to clinical translation

    DEFF Research Database (Denmark)

    Donath, M.Y.; Storling, J.; Berchtold, L.A.;

    2007-01-01

    The tale of cytokines and the beta-cell is a long story, starting with in vitro discovery in 1984, evolving via descriptive and phenomenological studies to detailed mapping of the signalling pathways, gene- and protein expression patterns, molecular and biochemical effector mechanisms to in vivo...

  12. Stimulation or inhibition of beta-carotene's biosynthesis by irradiation with γ-rays of Calendula Officinalis seeds

    International Nuclear Information System (INIS)

    It is important to see what is the effect of irradiation with gamma rays of Calendula officinalis (marigolds) seeds. Could it be a stimulation or a inhibition of beta-carotene's biosynthesis? This paper presents results of irradiation of germinated seeds of marigolds. It was carried out irradiation of seeds at 8 different doses ( 1 kRad, 3.3 kRad, 10 kRad, 25 kRad, 50 kRad, 100 kRad, 200 kRad, 500 krad), one set of seeds being unirradiated for comparison. The plants had been grown in the same conditions of light, temperature and humidity. The identification of β-carotene was realized through thin layer chromatography (TLC). The chemical concentrations of β-carotene in leaves and stalks of marigolds had been determined by Varian spectrophotometer. Quantitative determination of β-carotene was carried out through spectral analysis using a standard spectrum of carotenoids and chlorophyll a and b. (authors)

  13. Effect of bootstrap current on MHD equilibrium beta limit in heliotron plasmas

    International Nuclear Information System (INIS)

    The effect of bootstrap current on the beta limit of MHD equilibria is studied systematically by an iterative calculation of MHD equilibrium and the consistent bootstrap current in high beta heliotron plasmas. The LHD machine is treated as a standard configuration heliotron with an L=2 planar axis. The effects of vacuum magnetic configurations, pressure profiles and the vertical field control method are studied. The equilibrium beta limit with consistent bootstrap current is quite sensitive to the magnetic axis location for finite beta, compared with the currentless cases. For a vacuum configuration with the magnetic axis shifted inwards in the torus, even in the high beta regimes, the bootstrap current flows to increase the rotational transform, leading to an increase in the equilibrium beta limit. On the contrary, for a vacuum configuration with the magnetic axis shifted outwards in the torus, even in the low beta regimes, the bootstrap current flows so as to reduce the rotational transform; therefore, there is an acceleration of the Shafranov shift increase as beta increases, leading to a decrease in the equilibrium beta limit. The pressure profiles and vertical field control methods influence the equilibrium beta limit through the location of the magnetic axis for finite beta. These characteristics are independent of both device parameters, such as magnetic field strength, and device size in the low collisional regime. (author)

  14. Biological Effects of Ionizing Radiation

    International Nuclear Information System (INIS)

    The aim of this work is to verify the existence of the adaptive response phenomenon induced by low doses of ionizing radiation in living cells.A wild-type yeast Saccharomyces cerevisiae (Baker's yeast) was chosen as the biological target.As a parameter to quantify the sensibility of the target to radiation, the Lethal Dose 50 (LD50 ) was observed. In our experimental condition a value of (60 ± 1) Gy was measured for LD50 with Dose Rate of (0.44 ± 0.03) Gy/min. The method employed to show up the adaptive response phenomenon consisted in exposing the sample to low ''conditioning'' doses, which would initiate these mechanisms. Later the samples with and without conditioning were exposed to higher ''challenging'' doses (such as LD50), and the surviving fractions were compared. In order to maximize the differences, the doses and the time between irradiations were varied. The best results were obtained with both a conditioning dose of (0.44 ± 0.03) Gy and a waiting time of 2 hs until the application of the challenging dose. Following this procedures the 80% of the conditioned samples has survived, after receiving the application of the LD50. The adaptive response phenomenon was also verified for a wide range of challenging doses

  15. Atualizações sobre beta-hidroxi-beta-metilbutirato: suplementação e efeitos sobre o catabolismo de proteínas New findings on beta-hydroxy-beta-methylbutyirate: supplementation and effects on the protein catabolism

    Directory of Open Access Journals (Sweden)

    Everson Araújo Nunes

    2008-04-01

    Full Text Available O beta-hidroxi-beta-metilbutirato, metabólito do aminoácido leucina, vem sendo utilizado como suplemento alimentar, em situações específicas, com o intuito de aumentar ou manter a massa isenta de gordura. Os relatos dos efeitos do beta-hidroxi-beta-metilbutirato em estudos recentes fizeram crescer as expectativas sobre sua utilização em casos patológicos. Também foram demonstrados melhores resultados, quando da sua ingestão, no treinamento de força em indivíduos iniciantes e em idosos. Em humanos o beta-hidroxi-beta-metilbutirato tem sido usado como agente anti-catabólico, e em modelos animais foi demonstrado ser eficaz em inibir a atividade de vias proteolíticas em células musculares de indivíduos caquéticos in vitro e in vivo. Os mecanismos participantes desses processos envolvem: a inibição da atividade do sistema ubiquitina proteossoma ATP-dependente, a inibição de vias de sinalização com participação da proteína quinase C-alfa e a diminuição da concentração citoplasmática do fator nuclear - kappa B livre, eventos relacionados ao decréscimo da proteólise em células musculares.The leucine metabolite beta-hydroxy-beta-methylbutyrate has been used as a nutritional supplement in specific situations to prevent losing or to increase lean mass. Recent studies showed interesting results of beta-hydroxy-beta-methylbutyrate supplementation in certain disease states. Better results have also been demonstrated when it is taken by starters or old individuals doing strength training. In humans, beta-hydroxy-beta-methylbutyrate has been used as an anticatabolic agent and in animal models it has been demonstrated to be effective in inhibiting the activity of the proteolytic pathways in muscle cells of extremely weak individuals in vivo and in vitro. The mechanisms that participate in this process involve: inhibition of the ATP-ubiquitin-proteasome pathway, inhibition of the signalization pathways involving protein kinase C

  16. The effect of interferon-{beta} on mouse neural progenitor cell survival and differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, Marek [Neurology Department, University of Vermont College of Medicine, Burlington, VT (United States); Knight, Julia [Neuroscience Department, University of Vermont College of Medicine, Burlington, VT (United States); Tobita, Mari; Soltys, John; Panitch, Hillel [Neurology Department, University of Vermont College of Medicine, Burlington, VT (United States); Mao-Draayer, Yang, E-mail: yang.mao-draayer@vtmednet.org [Neurology Department, University of Vermont College of Medicine, Burlington, VT (United States)

    2009-10-16

    Interferon-{beta} (IFN-{beta}) is a mainstay therapy for relapse-remitting multiple sclerosis (MS). However, the direct effects of IFN-{beta} on the central nervous system (CNS) are not well understood. To determine whether IFN-{beta} has direct neuroprotective effects on CNS cells, we treated adult mouse neural progenitor cells (NPCs) in vitro with IFN-{beta} and examined the effects on proliferation, apoptosis, and differentiation. We found that mouse NPCs express high levels of IFN{alpha}/{beta} receptor (IFNAR). In response to IFN-{beta} treatment, no effect was observed on differentiation or proliferation. However, IFN-{beta} treated mouse NPCs demonstrated decreased apoptosis upon growth factor withdrawal. Pathway-specific polymerase chain reaction (PCR) arrays demonstrated that IFN-{beta} treatment upregulated the STAT 1 and 2 signaling pathway, as well as GFRA2, NOD1, Caspases 1 and 12, and TNFSF10. These results suggest that IFN-{beta} can directly affect NPC survival, possibly playing a neuroprotective role in the CNS by modulating neurotrophic factors.

  17. X-ray absorption spectroscopy in biological systems. Opportunities and limitations

    International Nuclear Information System (INIS)

    X-ray absorption spectroscopy has become more important for applications in the material sciences, geology, environmental science and biology, specifically in the field of molecular biology. The scope of this thesis is to add more experimental evidence in order to show how applicable X-ray absorption near edge structure (XANES) is to biology. Two biological systems were investigated, at the molecular level, lead uptake in plants and the effect of silver on bacteria. This investigation also included an analysis of the sensitivity of Pb L3- and Ag L3-XANES spectra with regard to their chemical environment. It was shown that Pb L3- and Ag L3-XANES spectra are sensitive to an environment with at least differences in the second coordination shell. The non-destructive and element specific properties of XANES are the key advantages that were very important for this investigation. However, in both projects the adequate selection of reference compounds, which required in some cases a chemical synthesis, was the critical factor to determine the chemical speciation and, finally, possible uptake and storage mechanisms for plants and antibacterial mechanisms of silver. The chemical environment of Pb in roots and leaves of plants from four different plant families and a lichen from a former lead mining site in the Eifel mountains in Germany was determined using both solid compounds and aqueous solutions of different ionic strength, which simulate the plant environment. The results can be interpreted in such a way that lead is sorbed on the surface of cell walls. Silver bonding as reaction with Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli bacteria was determined using inorganic silver compounds and synthesized silver amino acids. Silver binds to sulfur, amine and carboxyl groups in amino acids.

  18. X-ray absorption spectroscopy in biological systems. Opportunities and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Bovenkamp, Gudrun Lisa

    2013-05-15

    X-ray absorption spectroscopy has become more important for applications in the material sciences, geology, environmental science and biology, specifically in the field of molecular biology. The scope of this thesis is to add more experimental evidence in order to show how applicable X-ray absorption near edge structure (XANES) is to biology. Two biological systems were investigated, at the molecular level, lead uptake in plants and the effect of silver on bacteria. This investigation also included an analysis of the sensitivity of Pb L{sub 3}- and Ag L{sub 3}-XANES spectra with regard to their chemical environment. It was shown that Pb L{sub 3}- and Ag L{sub 3}-XANES spectra are sensitive to an environment with at least differences in the second coordination shell. The non-destructive and element specific properties of XANES are the key advantages that were very important for this investigation. However, in both projects the adequate selection of reference compounds, which required in some cases a chemical synthesis, was the critical factor to determine the chemical speciation and, finally, possible uptake and storage mechanisms for plants and antibacterial mechanisms of silver. The chemical environment of Pb in roots and leaves of plants from four different plant families and a lichen from a former lead mining site in the Eifel mountains in Germany was determined using both solid compounds and aqueous solutions of different ionic strength, which simulate the plant environment. The results can be interpreted in such a way that lead is sorbed on the surface of cell walls. Silver bonding as reaction with Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli bacteria was determined using inorganic silver compounds and synthesized silver amino acids. Silver binds to sulfur, amine and carboxyl groups in amino acids.

  19. Effects of beta-adrenoceptor drug stimulation on various models of gastric ulcer in rats.

    OpenAIRE

    Esplugues, J.; Lloris, J. M.; Martí-Bonmatí, E.; Morcillo, E. J.

    1982-01-01

    1. Experiments were designed to evaluate the effect of the pharmacological activation of beta-adrenoceptors on various models of gastric ulcer in the rat. 2. Pretreatment with the beta-adrenoceptor stimulant drugs, isoprenaline or salbutamol, significantly inhibited stress-induced gastric ulcers. This anti-ulcer effect was abolished by propranolol but not by atenolol, suggesting that beta 2-adrenoceptors mediate this response. 3. In the pylorus-ligation model, salbutamol inhibited lesion form...

  20. Radiosensitivity of Nicotiana protoplasts. Action on cell; cycle effects of low dose and fractionated irradiations; biological repair

    International Nuclear Information System (INIS)

    Leaf protoplasts of Nicotiana plumbaginifolia and Nicotiana sylvestris demonstrate five main qualities: they can be maintained as haploid lines; they constitute starting populations with a remarkable cytological homogeneity; they show a transient initial lag-phase; they yield very high plating efficiencies and retain permanently a complete differentiation capacity; being derived of a cell wall, they appear well adapted for fusion experiments or enzymatic dosages. The resumption of mitotic activity was followed by cytophotometric measurements, labelling experiments, nuclear sizing and enzymatic assays. The action of 5 Gy gamma-ray irradiations delayed entrance in the S-phase, provoked an otherwise not verified dependency between transcription, translation and protein synthesis, increased nuclear volumes in the G2-phase, and slightly stimulated the activity of a repair enzyme. The plating efficiency was a sensitive end-point which allowed the evaluation of the biological effectiveness of low to medium radiation-doses after gamma-ray and fast neutron irradiations. The neutron dose-RBE relationship increased from 3 to 25 when the dose decreased from 5 Gy to 5 mGy. When fractionated into low single doses only, a neutron dose of 300 mGy markedly increased its biological effectiveness: this phenomenon could not be explained by cell progression, and necessitated additional hypotheses involving other mechanisms in the specific action of low radiation doses. Radiation-induced UDS was measured in presence of aphidicolin. A beta-like DNA-polymerase was shown to be definitely involved in nuclear repair synthesis

  1. Biological effects of proton radiation: an update

    International Nuclear Information System (INIS)

    Proton radiation provides significant dosimetric advantages when compared with gamma radiation due to its superior energy deposition characteristics. Although the physical aspects of proton radiobiology are well understood, biological and clinical endpoints are understudied. The current practice to assume the relative biological effectiveness of low linear energy transfer (LET) protons to be a generic value of about 1.1 relative to photons likely obscures important unrecognised differentials in biological response between these radiation qualities. A deeper understanding of the biological properties induced by proton radiation would have both radiobiological and clinical impact. This article briefly points to some of the literature pertinent to the effects of protons on tissue-level processes that modify disease progression, such as angiogenesis, cell invasion and cancer metastasis. Recent findings hint that proton radiation may, in addition to offering improved radio-therapeutic targeting, be a means to provide a new dimension for increasing therapeutic benefits for patients by manipulating these tissue-level processes. (authors)

  2. Biological effects of inhaled radionuclides: summary of ICRP report 31

    International Nuclear Information System (INIS)

    The ICRP Task Group charged with evaluating the hazards associated with inhalation of plutonium and other radionuclides, enumerated the biological responses to inhaled radionuclides, identified tissues and cells at risk, derived risk coefficients for inhaled radionuclides from animal experiments for comparison with human data, and determined an equal effectiveness ratio of alpha emitters relative to beta-gamma emitters. High lung burdens of inhaled radionuclides result in profound structural and functional changes in which the pulmonary capillary endothelial cells are the most prominent cells at risk. Linear and nonlinear models used to evaluate lung cancer data from animal experiments project to risk coefficients between 0.84 and 1600 cases/106 animals/rad. The report concludes that the animal data support the current ICRP lung cancer risk of 2 x 10-3 Sv-1 (400 x 10+H-+H6 rad-1). Comparison of risk coefficients for beta-gamma emitters with those for alpha emitters, obtained using the same models, gave an Equal Effectiveness Ratio of 30 for inhaled alpha-emitting radionuclides. Thus, the experimental data support the ICRP decision to change the quality factor from 10 to 20 for alpha radiation. (H.K.)

  3. Effect of Beta-Carotene on Oxidative Stress and Expression of Cardiac Connexin 43

    International Nuclear Information System (INIS)

    Intervention studies have shown an increased mortality in patients who received beta-carotene. However, the mechanisms involved in this phenomenon are still unknown. Evaluate the influence of beta-carotene on oxidative stress and the expression of connexin 43 in rat hearts. Wistar rats, weighing approximately 100 g, were allocated in two groups: Control Group (n = 30), that received the diet routinely used in our laboratory, and Beta-Carotene Group (n = 28), which received beta-carotene (in crystal form, added and mixed to the diet) at a dose of 500 mg of beta carotene/kg of diet. The animals received the treatment until they reached 200-250g, when they were sacrificed. Samples of blood, liver and heart were collected to perform Western blotting and immunohistochemistry for connexin 43; morphometric studies, dosages of beta carotene by high performance liquid chromatography as well as reduced glutathione, oxidized glutathione and lipids hydroperoxides were performed by biochemical analysis. Beta-carotene was detected only in the liver of Beta-Carotene Group animals (288 ± 94.7 μg/kg). Levels of reduced/ oxidized glutathione were higher in the liver and heart of Beta-Carotene Group animals (liver - Control Group: 42.60 ± 1.62; liver - Beta-Carotene Group: 57.40 ± 5.90; p = 0.04; heart: - Control Group: 117.40 ± 1.01; heart - Beta-Carotene Group: 121.81 ± 1.32 nmol/mg protein; p = 0.03). The content of total connexin 43 was larger in Beta-Carotene Group. Beta-carotene demonstrated a positive effect, characterized by the increase of intercellular communication and improvement of anti-oxidizing defense system. In this model, mechanism does not explain the increased mortality rate observed with the beta-carotene supplementation in clinical studies

  4. Effect of Beta-Carotene on Oxidative Stress and Expression of Cardiac Connexin 43

    Energy Technology Data Exchange (ETDEWEB)

    Novo, Rosangela; Azevedo, Paula S.; Minicucci, Marcos F.; Zornoff, Leonardo A. M., E-mail: lzornoff@fmb.unesp.br; Paiva, Sergio A. R. [Faculdade de Medicina de Botucatu - Universidade Estadual Paulista ' Júlio de Mesquita Filho' , Botucatu, SP (Brazil)

    2013-09-15

    Intervention studies have shown an increased mortality in patients who received beta-carotene. However, the mechanisms involved in this phenomenon are still unknown. Evaluate the influence of beta-carotene on oxidative stress and the expression of connexin 43 in rat hearts. Wistar rats, weighing approximately 100 g, were allocated in two groups: Control Group (n = 30), that received the diet routinely used in our laboratory, and Beta-Carotene Group (n = 28), which received beta-carotene (in crystal form, added and mixed to the diet) at a dose of 500 mg of beta carotene/kg of diet. The animals received the treatment until they reached 200-250g, when they were sacrificed. Samples of blood, liver and heart were collected to perform Western blotting and immunohistochemistry for connexin 43; morphometric studies, dosages of beta carotene by high performance liquid chromatography as well as reduced glutathione, oxidized glutathione and lipids hydroperoxides were performed by biochemical analysis. Beta-carotene was detected only in the liver of Beta-Carotene Group animals (288 ± 94.7 μg/kg). Levels of reduced/ oxidized glutathione were higher in the liver and heart of Beta-Carotene Group animals (liver - Control Group: 42.60 ± 1.62; liver - Beta-Carotene Group: 57.40 ± 5.90; p = 0.04; heart: - Control Group: 117.40 ± 1.01; heart - Beta-Carotene Group: 121.81 ± 1.32 nmol/mg protein; p = 0.03). The content of total connexin 43 was larger in Beta-Carotene Group. Beta-carotene demonstrated a positive effect, characterized by the increase of intercellular communication and improvement of anti-oxidizing defense system. In this model, mechanism does not explain the increased mortality rate observed with the beta-carotene supplementation in clinical studies.

  5. Evaluation of energy deposition to the urinary bladder wall considering radiosensitive basal cells by beta-ray emitters

    International Nuclear Information System (INIS)

    The present report describes the dose evaluation of the urinary bladder since its absorbed dose from radiopharmaceuticals tends to be higher than other organs. For an accurate dose evaluation, a simple bladder model considering radiosensitive basal cells was used to calculate SAF (specific absorbed fractions) for the basal cells and the whole bladder wall from mono energetic photon and electron sources using Monte Carlo simulation. Furthermore, S values (the mean absorbed doses for the target organ per unit cumulated activity in the source organ) were evaluated for 36 beta-ray emitters. Consequently, considering basal cells and beta particle spectra in the evaluation of absorbed dose for the urinary bladder are very important for an accurate evaluation. (author)

  6. Biological Effects of Irradiated Fats

    International Nuclear Information System (INIS)

    Rats were fed with a diet containing 20% of irradiated oils. If the oils were irradiated with 2.5 Mrad, there was no indication of detrimental effects during the course of 80 weeks. Oils irradiated with 10 Mrad, however, caused an increase in lethality after a lag period of 9 to 12 months. Irradiation with 50 Mrad caused weight losses after 24 weeks, disturbed liver function, and hypoproteinaemia, with a relative increase in gamma globulins. No animal of this group exceeded a life-span of 75 weeks. Irradiation with 100 Mrad caused immediate toxic symptoms and a high lethality. There is no indication that peroxides are responsible for the toxicity of the irradiated oils. Because of the high content of dimeric products in the irradiated oils, it is assumed that dimerization of fatty acids is the cause of damage. (author)

  7. Biological Effects Of Artificial Illumination

    Science.gov (United States)

    Corth, Richard

    1980-10-01

    We are increasingly being warned of the possible effects of so called "polluted" light, that is light that differs in spectral content from that of sunlight. We should be concerned, we are told, because all animals and plants have evolved under this natural daylight and therefore any difference between that illuminant and the artificial illuminants that are on the market today, is suspect. The usual presentation of the differences between the sunlight and the artificial illuminants are as shown in Figure 1. Here we are shown the spectral power distribution of sunlight and Cool White fluorescent light. The spectral power distributions of each have been normalized to some convenient wavelength so that each can be seen and easily compared on the same figure. But this presentation is misleading for one does not experience artificial illuminants at the same intensity as one experiences sunlight. Sunlight intensities are ordinarily found to be in the 8000 to 10,000 footcandle range whereas artificial illuminants are rarely experienced at intensity levels greater than 100 footcandles. Therefore a representative difference between the two types of illumination conditions is more accurately represented as in Figure 2. Thus if evolutionary adaptations require that humans and other animals be exposed to sunlight to ensure wellbeing, it is clear that one must be exposed to sunlight intensities. It is not feasible to expect that artificially illuminated environments will be lit to the same intensity as sunlight

  8. Biological effects of prenatal irradiation

    International Nuclear Information System (INIS)

    After large releases of radionuclides, exposure of the embryo or fetus can take place by external irradiation or uptake of radionuclies. The embryo and fetus are radiosensitive throughout prenatal development. The quality and extent of radiation effects depend on the development stage. During the preimplantation period (one to 10 days postconception, p.c.) a radiation exposure of at least 0.2 Gy can cause the death of the embryo. Malformations are only observed in rare cases when genetic predisposition exist. Macroscopic, anatomical malformations are induced only after irradiation during the major organogenesis (two to eight weeks p.c.). A radiation dose of about 0.2 Gy is a doubling dose for the malformation risks as extrapolated from experiments with rodents. The human embryo may be more radioresistant. During early fetogenesis (8-15 weeks p.c.) a high radiosensitivity exists for the developmental of the brain. Radiation doses of 1.0 Gy cause severe mental retardation in about 40% of the exposed fetuses. It must be taken into account that a radiation exposure during the fetal period can also induce cancer. It is generally assumed that the risk exists at about the same level as for children. (Author)

  9. Is the treatment effect of IFN-beta restored after the disappearance of neutralizing antibodies?

    DEFF Research Database (Denmark)

    Sorensen, P S; Koch-Henriksen, Nils; Flachs, Esben Meulengracht; Bendtzen, K

    2008-01-01

    comparing the NAb-positive with the NAb-negative periods was 1.98 (95% confidence interval: 1.32-2.97). CONCLUSION: Under NAb-positive periods, the clinical effect of IFN-beta was abolished. When NAbs disappeared spontaneously under continued treatment, patients regained the full effect of INF-beta-1b...

  10. Electromagnetic effects on dynamics of high-beta filamentary structures

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wonjae; Krasheninnikov, Sergei I., E-mail: skrash@mae.ucsd.edu [University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States); Umansky, Maxim V. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Angus, J. R. [Naval Research Laboratory, 4555 Overlook Avenue, Washington, DC 20375 (United States)

    2015-01-15

    The impacts of the electromagnetic effects on blob dynamics are considered. Electromagnetic BOUT++ simulations on seeded high-beta blobs demonstrate that inhomogeneity of magnetic curvature or plasma pressure along the filament leads to bending of the blob filaments and the magnetic field lines due to increased propagation time of plasma current (Alfvén time). The bending motion can enhance heat exchange between the plasma facing materials and the inner scrape-off layer (SOL) region. The effects of sheath boundary conditions on the part of the blob away from the boundary are also diminished by the increased Alfvén time. Using linear analysis and BOUT++ simulations, it is found that electromagnetic effects in high temperature and high density plasmas reduce the growth rate of resistive drift wave instability when resistivity drops below a certain value. The blobs temperature decreases in the course of its motion through the SOL and so the blob can switch from the electromagnetic to the electrostatic regime where resistive drift waves become important again.

  11. Assessment of beta-emitter radionuclides in biological samples using liquid scintillation counting. Application to the study of internal doses in molecular and cellular biology techniques

    International Nuclear Information System (INIS)

    The radioisotopic techniques used in Molecular and Cellular Biology involve external and internal irradiation risk. It is necessary to control the possible internal contamination associated to the development of these techniques. The internal contamination risk can be due to physical and chemical properties of the labelled compounds, aerosols generated during the performance technique. The aim of this work was to estimate the possible intake of specific beta emitters during the technique development and to propose the required criterions to perform Individual Monitoring. The most representative radioisotopic techniques were selected attending their potential risk of internal contamination. Techniques were analysed applying IAEA methodology according to the used activity in each technique. It was necessary to identify the worker groups that would require individual monitoring on the base of their specific risk. Different measurement procedures were applied to study the possible intake in group risk and more than 160 persons were measured by in vitro bioassay. (Author) 96 refs

  12. Interleukin 1 receptor antagonist mediates the beneficial effects of systemic interferon beta in mice: implications for rheumatoid arthritis

    NARCIS (Netherlands)

    M. Corr; D.L. Boyle; L.M. Ronacher; B.R. Lew; L.G. van Baarsen; P.P. Tak; G.S. Firestein

    2011-01-01

    Objectives Interferon beta (IFN beta) therapy is effective in multiple sclerosis and murine models of arthritis. Surprisingly, systemic IFN beta treatment induces only minimal improvement in rheumatoid arthritis (RA). To explain this paradox, the authors evaluated the mechanism of IFN beta benefit i

  13. Biological Effect of Magnetic Field in Mice

    Institute of Scientific and Technical Information of China (English)

    Zhao-Wei ZENG

    2005-01-01

    Objective: To study the biological effect of magnetic field in mice bodies. Method: With a piece of permanent magnet embeded in mice bodies beside the femoral artery and vein to measure the electrophoretic velocity(um/s). Result: The magnetic field in mice bodies on the experiment group that the electrophoretic velocity is faster more than control and free group.Conclusion:The magnetic field in animal's body can raise the negative electric charges on the surface of erythrocyte to improve the microcirculation, this is the biological effect of magnetic field.

  14. New Scientific Pearl about Biologic Effect of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    S. A. Alamdaran

    2008-01-01

    Full Text Available Soon after the discovery of X-ray by Rontgen in 1895, it became evident that radiation can cause some somatic damage to tissues. The hazards of X-ray exposure were clearly known when many large hospitals had radiology departments. The greatest increased in knowledge about X-ray risks had accrued from the dropping of the two atomic bombs in Japan in 1945 and some other atomic accident. For example, among the Japanese bomb survivors from Hiroshima and Nagasaki, there have been about 400 extra cancer deaths. These were the origin of radiology personnel and people fear from radiation exposure and resistant in against simple X-ray exam (radiophobia. However, new scientific data on the effects radiation on survivors, especially about biologic effect of ionizing rays, background radiation exposure, amount of endogenous radiation, hormosis phenomenon and comparison radiation risk with other risk over lifetime are still being continuously revised and risk estimates updated. Fundamentally, this risk is much"nlower than whatever already estimated and it is insignificant in diagnostic domain. Better perception of physician from these instances help to prevent of false radiophobia and to make proper use of diagnostic and therapeutic advantages of ionizing beam.

  15. Neuroprotective effects of Triticum aestivum L. against beta-amyloid-induced cell death and memory impairments.

    Science.gov (United States)

    Jang, Jung-Hee; Kim, Chang-Yul; Lim, Sun Ha; Yang, Chae Ha; Song, Kyung-Sik; Han, Hyung Soo; Lee, Hyeong-Kyu; Lee, Jongwon

    2010-01-01

    beta-Amyloid (A beta) is a key component of senile plaques, neuropathological hallmarks of Alzheimer's disease (AD) and has been reported to induce cell death via oxidative stress. This study investigated the protective effects of Triticum aestivum L. (TAL) on A beta-induced apoptosis in SH-SY5Y cells and cognitive dysfunctions in Sprague-Dawley (SD) rats. Cells treated with A beta exhibited decreased viability and apoptotic features, such as DNA fragmentation, alterations in mitochondria and an increased Bax/Bcl-2 ratio, which were attenuated by TAL extract (TALE) pretreatment. To elucidate the neuroprotective mechanisms of TALE, the study examined A beta-induced oxidative stress and cellular defense. TALE pretreatment suppressed A beta-increased intracellular accumulation of reactive oxygen species (ROS) via up-regulation of glutathione, an essential endogenous antioxidant. To further verify the effect of TALE on memory impairments, A beta or scopolamine was injected in SD rats and a water maze task conducted as a spatial memory test. A beta or scopolamine treatment increased the time taken to find the platform during training trials, which was decreased by TALE pretreatment. Furthermore, one of the active components of TALE, total dietary fiber also effectively inhibited A beta-induced cytotoxicity and scopolamine-caused memory deficits. These results suggest that TALE may have preventive and/or therapeutic potential in the management of AD. PMID:19441012

  16. Ornithogalum virens as a plant assay for beta and gamma radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    Herron, V J

    1979-01-01

    The purpose of this study was to determine if the monocotyledonous angiosperm, Ornithogalum virens (Quintanilha and Cabral, 1947), could be used in such a biological assay system. After exposing O. virens plants to acute (/sup 60/Co) and chronic (/sup 137/Cs) gamma radiation and internal beta radiation (/sup 32/P), lethality (LD/sub 50/, LD/sub 100/), growth inhibition, and chromosome aberrations were investigated. The LD/sub 50/ and LD/sub 100/ for acute gamma radiation were estimated to be between 0.91 to 1.8 krad and less than 3.6 krad, respectively. Though growth inhibition and abnormal growth were observed in the acute and chronic gamma radiation studies, the changes in the growth of the plants were so variable that these parameters were found to be unreliable measures of radiation effects. Chromosome aberrations were a more reliable measure of radiation damage because linear relationships between total aberrations and dose were found for both gamma and beta radiation.

  17. Biological effectiveness of neutrons: Research needs

    Energy Technology Data Exchange (ETDEWEB)

    Casarett, G.W.; Braby, L.A.; Broerse, J.J.; Elkind, M.M.; Goodhead, D.T.; Oleinick, N.L.

    1994-02-01

    The goal of this report was to provide a conceptual plan for a research program that would provide a basis for determining more precisely the biological effectiveness of neutron radiation with emphasis on endpoints relevant to the protection of human health. This report presents the findings of the experts for seven particular categories of scientific information on neutron biological effectiveness. Chapter 2 examines the radiobiological mechanisms underlying the assumptions used to estimate human risk from neutrons and other radiations. Chapter 3 discusses the qualitative and quantitative models used to organize and evaluate experimental observations and to provide extrapolations where direct observations cannot be made. Chapter 4 discusses the physical principles governing the interaction of radiation with biological systems and the importance of accurate dosimetry in evaluating radiation risk and reducing the uncertainty in the biological data. Chapter 5 deals with the chemical and molecular changes underlying cellular responses and the LET dependence of these changes. Chapter 6, in turn, discusses those cellular and genetic changes which lead to mutation or neoplastic transformation. Chapters 7 and 8 examine deterministic and stochastic effects, respectively, and the data required for the prediction of such effects at different organizational levels and for the extrapolation from experimental results in animals to risks for man. Gaps and uncertainties in this data are examined relative to data required for establishing radiation protection standards for neutrons and procedures for the effective and safe use of neutron and other high-LET radiation therapy.

  18. Biological effectiveness of neutrons: Research needs

    International Nuclear Information System (INIS)

    The goal of this report was to provide a conceptual plan for a research program that would provide a basis for determining more precisely the biological effectiveness of neutron radiation with emphasis on endpoints relevant to the protection of human health. This report presents the findings of the experts for seven particular categories of scientific information on neutron biological effectiveness. Chapter 2 examines the radiobiological mechanisms underlying the assumptions used to estimate human risk from neutrons and other radiations. Chapter 3 discusses the qualitative and quantitative models used to organize and evaluate experimental observations and to provide extrapolations where direct observations cannot be made. Chapter 4 discusses the physical principles governing the interaction of radiation with biological systems and the importance of accurate dosimetry in evaluating radiation risk and reducing the uncertainty in the biological data. Chapter 5 deals with the chemical and molecular changes underlying cellular responses and the LET dependence of these changes. Chapter 6, in turn, discusses those cellular and genetic changes which lead to mutation or neoplastic transformation. Chapters 7 and 8 examine deterministic and stochastic effects, respectively, and the data required for the prediction of such effects at different organizational levels and for the extrapolation from experimental results in animals to risks for man. Gaps and uncertainties in this data are examined relative to data required for establishing radiation protection standards for neutrons and procedures for the effective and safe use of neutron and other high-LET radiation therapy

  19. Proton-Induced X-ray Emission (PIXE) Analysis and DNA-chain Break study in rat hepatocarcinogenesis: A possible chemopreventive role by combined supplementation of vanadium and beta-carotene

    OpenAIRE

    Kanjilal NB; Doloi Manika; Vijayan V; Kulkarni Indira; Mukherjee Sutapa; Chattopadhyay Mitali; Chatterjee Malay

    2005-01-01

    Abstract Combined effect of vanadium and beta-carotene on rat liver DNA-chain break and Proton induced X-ray emission (PIXE) analysis was studied during a necrogenic dose (200 mg/kg of body weight) of Diethyl Nitrosamine (DENA) induced rat liver carcinogenesis. Morphological and histopathological changes were observed as an end point biomarker. Supplementation of vanadium (0.5 ppm ad libitum) in drinking water and beta-carotene in the basal diet (120 mg/Kg of body weight) were performed four ...

  20. The Role of Non-Targeted Effects as Mediators in the Biological Effects of Proton Irradiation

    Science.gov (United States)

    Cucinotta, Francis A.; Dicello, John F.

    2006-01-01

    In recent years, the hypothesis that non-DNA targets are primary initiators and mediators of the biological effects of ionizing radiation, such as proton beams and heavy ions, has gained much interest. These phenomena have been denoted as non-targeted or bystander effects to distinguish them from the more traditionally studied model that focuses on direct damage to DNA causing chromosomal rearrangements and mutations as causative of most biological endpoints such as cell killing, tissue damage, and cancer. We review cellular and extra-cellular structures and signal transduction pathways that have been implemented in these recent studies. Non-targeted effects of interest include oxidative damage to the cytoplasm and mitochondria, disruption of the extra-cellular matrix, and modification of cytokine signaling including TGF-beta, and gap junction communication. We present an introduction to these targets and pathways, and contrast there role with DNA damage pathways.

  1. The full curvature effect expected in early X-ray afterglow emission of gamma-ray bursts

    OpenAIRE

    Qin, Y. -P.

    2008-01-01

    We explore the influence of the full curvature effect on the flux of early X-ray afterglow of gamma-ray bursts (GRBs) in cases when the spectrum of the intrinsic emission is a power-law. We find that the well-known $t^{-(2+\\beta)}$ curve is present only when the intrinsic emission is extremely short or the emission arises from an exponential cooling. The time scale of this curve is independent of the Lorentz factor. The resulting light curve would contain two phases when the intrinsic emissio...

  2. Registration methods of the differential X-ray projections of biological objects

    International Nuclear Information System (INIS)

    The image contrast improvement conditions for biological objects at X-ray projections digital deduction obtained at spectrum varying within energy range 5-25 keV are considered. It is shown, that developed methods for spectral lines selection with help of semi-transparent X-ray monochromators may be used for X-ray differential images dynamical visualization problem solution. The practical opportunities of the differential method are demonstrated with help of the projection scheme on the base of selective filters and standard X-ray tube which qualitatively simulating the spectrum transformation. Comparison of the differential method with phase contrast way is conducted

  3. Biological dose estimation for accidental supra-high dose gamma-ray exposure

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y., E-mail: yingchen29@yahoo.com.cn [Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Haidian District, Beijing 100850 (China); Yan, X.K. [Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Haidian District, Beijing 100850 (China); Department of Radiation Safety, Beijing Institute of Nuclear and Chemical Safety, 14 Guan-cun, Dongcheng District, Beijing 100077 (China); Du, J.; Wang, Z.D.; Zhang, X.Q.; Zeng, F.G.; Zhou, P.K. [Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Haidian District, Beijing 100850 (China)

    2011-09-15

    To correctly estimate the biological dose of victims accidentally exposed to a very high dose of {sup 60}Co gamma-ray, a new dose-effect curve of chromosomal dicentrics/multicentrics and rings in the supra-high dose range was established. Peripheral blood from two healthy men was irradiated in vitro with doses of {sup 60}Co gamma-rays ranging from 6 to 22 Gy at a dose rate of 2.0 Gy/min. Lymphocytes were concentrated, cultured and harvested at 52 h, 68 h and 72 h. The numbers of dic + r were counted. The dose-effect curves were established and validated using comparisons with doses from the Tokai-mura accident and were then applied to two victims of supra-high dose exposure accident. The results indicated that there were no significant differences in chromosome aberration frequency among the different culture times from 52 h to 72 h. The 6-22 Gy dose-effect curve was fitted to a linear quadratic model Y = -2.269 + 0.776D - 7.868 x l0{sup -3}D{sup 2}. Using this mathematic model, the dose estimates were similar to data from Tokai-mura which were estimated by PCC ring. Whole body average doses of 9.7 Gy and 18.1 Gy for two victims in the Jining accident were satisfactorily given. We established and successfully applied a new dose-effect curve of chromosomal dicentrics plus ring (dic + r) after 6-22 Gy {gamma}-irradiation from a supra-high dose {sup 60}Co gamma-ray accident.

  4. Antithrombotic effects of beta2-adrenergic receptor blockade on top of beta1-receptor blockade in patients with acute coronary syndrome or heart failure : a systematic review

    NARCIS (Netherlands)

    De Peuter, O.R.; Lussana, F.; Peters, R.J.; Büller, H.R.; Kamphuisen, P.W.

    2009-01-01

    Background: Non-selective beta1 + 2 blockers may have specific antithrombotic effects not present in eta1-blockers, due to a eta2-specific effect on sympathetic activity. Our aim was to assess the influence of eta2-receptor suppression on top of selective beta1-receptor blockade on the occurrence of

  5. Effect of apotransferrin, lactoferrin and ovotransferrin on the hydroxyl radical mediated degradation of beta-glucan.

    Science.gov (United States)

    Faure, Audrey M; Nyström, Laura

    2016-08-01

    Beta-glucan is a polysaccharide widely accepted and used as a functional ingredient due to its positive effects on human health. However, beta-glucan is readily degraded in aqueous systems in presence of a hydroxyl radical generating system such as ascorbic/iron(II). In the present study, we tested whether iron binding proteins; apotransferrin, lactoferrin and ovotransferrin; could prevent the hydroxyl radical mediated degradation of beta-glucan. The radical formation was investigated by ESR spectroscopy and the polysaccharide degradation was monitored by the viscosity loss of the solutions. Apo-transferrin increased the formation of hydroxyl radicals and this related with a faster degradation of beta-glucan. Lactoferrin did not have any effect on the ascorbate induced degradation of beta-glucan, whereas ovotransferrin completely inhibited the hydroxyl radical generation by a system containing ascorbic acid and iron(II). However, the presence of ovotransferrin in beta-glucan decreased the viscosity of the solution, which was accompanied by the apparition of a precipitate, indicating a potential interaction between the protein and beta-glucan. FT-IR analyses indicate the presence of beta-glucan and ovotransferrin in both precipitate and supernatant, as well as the occurrence of interactions between the two compounds. This study reveals that ovotransferrin is a promising candidate for inhibiting the formation of ascorbate/iron(II) induced hydroxyl radicals in beta-glucan solutions. PMID:26988468

  6. Contribution of beta 1- and beta 2-adrenoceptors of human atrium and ventricle to the effects of noradrenaline and adrenaline as assessed with (-)-atenolol.

    OpenAIRE

    Lemoine, H.; Schönell, H.; Kaumann, A. J.

    1988-01-01

    1. (-)-Atenolol was used as a tool to assess the function of beta 1- and beta 2-adrenoceptors in human heart. Right atrial and left ventricular preparations from patients undergoing open heart surgery were set up to contract isometrically. Membrane particles were prepared for beta-adrenoceptor labelling with [3H]-(-)-bupranolol and adenylate cyclase assays. 2. The positive inotropic effects of (-)-noradrenaline were antagonized to a similar extent by (-)-atenolol in atrial and ventricular pre...

  7. Biological effect of carbon beams on cultured human cells

    International Nuclear Information System (INIS)

    This study was performed to determine the biological effect of carbon beams on 13 human tumor cells, in comparison with 200 KVp X-rays. Carbon beams were generated by the Riken Ring Cyclotron. The RBE (relative biological effectiveness) values were distributed from 1.46 to 2.20 for LET of 20 keV/μm, and 2.29-3.54 for 80 keV/μm. The RBEs were increased in all cell lines as the LET of carbon beams was increased from 20 to 80 keV/μm. There was no significant difference in radiosensitivity between cells from adenocarcinoma and those from squamous cell carcinoma. The relationship between the radiosensitivity of cells to X-rays and RBE was analyzed, but no significant correlation was suggested. Several survival curves of 20-40 keV/μm carbon beam irradiation showed the initial shoulders and the recovery ratios between two split doses were determined. Recovery was observed for LET of 2O keV/μm but not for that of 40 keV/μm. Furthermore, recovery ratios were 1.0-1.8, smaller than those for X-rays (1.5-2.4). (author)

  8. Recurrence rate and radiation cataract of pterygium eye after postoperative 90Sr beta-ray irradiation

    International Nuclear Information System (INIS)

    The recurrence rate of pterygium was studied in 99 eyes that underwent 90Sr β-ray irradiation after surgery and in 12 eyes that did not. The follow-up period was 1 to 7 years. The recurrence rate was 2.9% in the 69 eyes which had undergone irradiation from the third day after operation, and 13.3% in the 30 eyes which had undergone irradiation from the seventh day or later after operation. The recurrence rate was 75% in the eyes which had undergone no irradiation. In 62 cases of postoperative irradiation in one eye, the presence of radiation cataract was investigated using the other eye as a control. The follow-up period was one to seven years. No radiation cataract was detected. Postoperative 90Sr β-ray irradiation is an effective and safe method of preventing recurrence of pterygium when applied from the third day after operation, one 1000 rad dose every week, 4 times consecutively. (author)

  9. Advances in the biological effects of terahertz wave radiation.

    Science.gov (United States)

    Zhao, Li; Hao, Yan-Hui; Peng, Rui-Yun

    2014-01-01

    The terahertz (THz) band lies between microwave and infrared rays in wavelength and consists of non-ionizing radiation. Both domestic and foreign research institutions, including the army, have attached considerable importance to the research and development of THz technology because this radiation exhibits both photon-like and electron-like properties, which grant it considerable application value and potential. With the rapid development of THz technology and related applications, studies of the biological effects of THz radiation have become a major focus in the field of life sciences. Research in this field has only just begun, both at home and abroad. In this paper, research progress with respect to THz radiation, including its biological effects, mechanisms and methods of protection, will be reviewed. PMID:25722878

  10. Advances in the biological effects of terahertz wave radiation

    Institute of Scientific and Technical Information of China (English)

    Li Zhao; Yan-Hui Hao; Rui-Yun Peng

    2014-01-01

    The terahertz (THz) band lies between microwave and infrared rays in wavelength and consists of non-ionizing radiation. Both domestic and foreign research institutions, including the army, have attached considerable importance to the research and development of THz technology because this radiation exhibits both photon-like and electron-like properties, which grant it considerable application value and potential. With the rapid development of THz technology and related applications, studies of the biological effects of THz radiation have become a major focus in the field of life sciences. Research in this field has only just begun, both at home and abroad. In this paper, research progress with respect to THz radiation, including its biological effects, mechanisms and methods of protection, will be reviewed.

  11. Biological effect of nitrogen ion implantation on stevia

    International Nuclear Information System (INIS)

    Dry seed of stevia were implanted by 35∼150 keV nitrogen ions with various doses. The biological effect in M1 was studied. The results showed that nitrogen ion beam was able to induce variation on chromosome structure in root tip cells. The rate of cells with chromosome aberration was increased with ion beam energy and dose added, but there was on significant linear regression relationship between ion dose and aberration rate. The results indicated the seedling height reduced with the increasing of dose for ion beam. The biological effect of nitrogen ion beam on M1 stevia was lower than that of γ-rays. (6 refs., 1 fig., 4 tabs.)

  12. RELATIVE BIOLOGICAL EFFECTIVENESS IN A PROTON SOBP

    Czech Academy of Sciences Publication Activity Database

    Vachelová, Jana; Michaelidesová, Anna; Litvinchuk, Alexandra; Vondráček, V.; Davídková, Marie

    Vol. 34. Bratislava : SMU - Faculty of Public Health, 2014. s. 121-121. ISBN 978-80-89384-08-2. [XXXVI.Dny radiační ochrany. 10.11.2014-14.11.2014, Poprad] Institutional support: RVO:61389005 Keywords : relative biological effectiveness * Spread-Out Bragg Peak * linear energy transfer Subject RIV: BO - Biophysics

  13. Biological radiation effects and radioprotection standards

    International Nuclear Information System (INIS)

    In this report, after recalling the mode of action of ionizing radiations, the notions of dose, dose equivalents and the values of natural irradiation, the author describes the biological radiation effects. Then he presents the ICRP recommendations and their applications to the french radioprotection system

  14. Exploiting Allee effects for managing biological invasions

    Czech Academy of Sciences Publication Activity Database

    Tobin, P. C.; Berec, Luděk; Liebhold, A. M.

    2011-01-01

    Roč. 14, č. 6 (2011), s. 615-624. ISSN 1461-023X Grant ostatní: National Centre for Ecological Analysis and Synthesis(US) EF-0553768 Institutional research plan: CEZ:AV0Z50070508 Keywords : Allee dynamics * biological invasions * component Allee effect Subject RIV: EH - Ecology, Behaviour Impact factor: 17.557, year: 2011

  15. Targeting beta III-tubulin in glioblastoma multiforme: from cell biology and histopathology to cancer therapeutics

    Czech Academy of Sciences Publication Activity Database

    Katsetos, C.D.; Dráber, Pavel; Kavallaris, M.

    2011-01-01

    Roč. 11, č. 8 (2011), s. 719-728. ISSN 1871-5206 R&D Projects: GA ČR GAP302/10/1759 Institutional research plan: CEZ:AV0Z50520514 Keywords : glioblastoma multiforme * tubulin binding agent * epothilones Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.862, year: 2011

  16. Tritium $\\beta$-decay in chiral effective field theory

    CERN Document Server

    Baroni, A; Kievsky, A; Marcucci, L E; Schiavilla, R; Viviani, M

    2016-01-01

    We evaluate the Fermi and Gamow-Teller (GT) matrix elements in tritium \\beta-decay by including in the charge-changing weak current the corrections up to one loop recently derived in nuclear chiral effective field theory (\\chi EFT). The trinucleon wave functions are obtained from hyperspherical-harmonics solutions of the Schrodinger equation with two- and three-nucleon potentials corresponding to either \\chi EFT (the N3LO/N2LO combination) or meson-exchange phenomenology (the AV18/UIX combination). We find that contributions due to loop corrections in the axial current are, in relative terms, as large as (and in some cases, dominate) those from one-pion exchange, which nominally occur at lower order in the power counting. We also provide values for the low-energy constants multiplying the contact axial current and three-nucleon potential, required to reproduce the experimental GT matrix element and trinucleon binding energies in the N3LO/N2LO and AV18/UIX calculations.

  17. Chronic beta-blocker treatment in patients with advanced heart failure - Effects on neurohormones

    NARCIS (Netherlands)

    Teisman, ACH; van Veldhuisen, DJ; Boomsma, F; de Kam, PJ; Pinto, YM; de Zeeuw, D; van Gilst, WH

    2000-01-01

    Background: To date, the use of beta-blockers in treating patients with chronic heart failure gains support, this since several large clinical trials reported reduced mortality after chronic beta-blockade. Part of these beneficial effects may result from inhibition of deleterious neurohormone activa

  18. The effect of gamma rays on carrots

    International Nuclear Information System (INIS)

    The effects of several doses (5-400 Gy) of gamma rays from a 137Cs source were studied on several biological indices in carrots. Doses higher than 50 Gy reduced the wet weight of the cells in the suspension medium whereas the doses of 5 and 10 Gy affected the wet weight positively and to a lesser extent the dry weight. This may be due to higher water absorption of the irradiated cells since their number was less than that of the control. The different doses did not affect the chromosome number of the cells but reduced the cell division rates. At doses higher than 200 Gy no singel cell was recorded as dividing after two days of irradiation. A week later, however, the cells seemed to have recovered some ability for division, but with an increase of prophase stage in mitosis and also in the mitotic division abnormalities. Cells irradiation with 10 Gy caused the cells to differentiate and to form somatic embryos due to halting the effect of 2,4-D hormon. Higher doses, however, prohibited or reduced cells differentiation, probably due to higher mitotic division abnormalities. Nevertheless, it has been possible to attain mature plants from all treatments except for the 400 Gy. The low doses of 5 and 10 Gy, contrary to the higher ones, affected positively the speed of seed germination, increased the plant height, and also increased the root weight. 11 refs. (author)

  19. PIXE analysis of suspended particulate matter originally collected for beta-ray absorption mass monitoring

    International Nuclear Information System (INIS)

    A method of transferring suspended particulate matter (SPM) from the used filter of a beta-absorption mass monitor to a polycarbonate filter for subsequent PIXE analysis has been developed. The method allows determination of the relative elemental composition of SPM. It was demonstrated that PIXE analysis can detect S, Cl, Fe and Zn in SPM sampled over a one-hour period. (author)

  20. Nuclear energy: biological effects and environmental impact

    International Nuclear Information System (INIS)

    This thesis is concerned with the large development of nuclear power plants and the recent nuclear catastrophe which has made clear how the hazards resulting from radioactivity affect public health and the environment. Environmental effects of nuclear power plants operating in normal conditions are small, but to obtain nuclear power plants of reduced radioactivity, optimization of their design, construction, operation and waste processing plays a decisive role. Biological effects of ionizing radiations and environmental impacts of Nuclear Power plants are developed

  1. II. Biological studies of radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, J.H.

    1948-05-24

    With the completion of the 184 inch cyclotron in Berkeley and the successful construction of a deflector system, it was possible to bring the 190 Mev deuteron and the 380 Mev alpha beams out into the air and to begin a study of the effects of high-energy deuteron beams by direct irradiation of biological specimens. The direct biological use of deuteron beams was attempted earlier in Berkeley by Marshak, MacLeish, and Walker in 1940. These and other investigators have been aware for some time of the potential usefulness of high energy particle beams for radio-biological studies and their suitability for biological investigations. R.R. Wilson advanced the idea of using fast proton beams to deliver radiation and intervening tissues. R.E. Zirkle pointed out that such particle beams may be focused or screened until a cross-section of the beam is small enough to study effects of irradiation under the microscope on single cells or on parts of single cells. This article gives an overview of the radiological use of high energy deuteron beams, including the following topics: potential uses of high energy particle beams; experiments on the physical properties of the beam; lethal effect of the deuteron beam on mice.

  2. Effect of prolonged 5-hydroxytryptamine uptake inhibition by paroxetine on cortical. beta. sub 1 and. beta. sub 2 -adrenoceptors in rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, D.R.; Palmer, K.J.; Johnson, A.M. (SmithKline Beecham Pharmaceuticals, Essex (England))

    1990-01-01

    The effects of prolonged oral administration of the antidepressants paroxetine and amitriptyline on rat brain cortical {beta}{sub 1}- and {beta}{sub 2}-adrenoceptor numbers and affinities were investigated using ({sup 3}H)-CGP 12177. Although amitriptyline, 27 mg/kg, caused a significant 20% reduction in the number of {beta}{sub 1}-adrenoceptors, paroxetine, at does up to 8.9 mg/kg p.o., did not influence binding of ({sup 3}H)-CGP 12177 to cortical {beta}{sub 1}- or {beta}{sub 2}-adrenoceptors. This study with paroxetine provides further evidence that the down-regulation of central {beta}{sub 1}-adrenoceptors in rat brain after repeated administration is not a property of all antidepressant drugs.

  3. Effects of X-Ray Dose On Rhizosphere Studies Using X-Ray Computed Tomography.

    Directory of Open Access Journals (Sweden)

    Susan Zappala

    Full Text Available X-ray Computed Tomography (CT is a non-destructive imaging technique originally designed for diagnostic medicine, which was adopted for rhizosphere and soil science applications in the early 1980s. X-ray CT enables researchers to simultaneously visualise and quantify the heterogeneous soil matrix of mineral grains, organic matter, air-filled pores and water-filled pores. Additionally, X-ray CT allows visualisation of plant roots in situ without the need for traditional invasive methods such as root washing. However, one routinely unreported aspect of X-ray CT is the potential effect of X-ray dose on the soil-borne microorganisms and plants in rhizosphere investigations. Here we aimed to i highlight the need for more consistent reporting of X-ray CT parameters for dose to sample, ii to provide an overview of previously reported impacts of X-rays on soil microorganisms and plant roots and iii present new data investigating the response of plant roots and microbial communities to X-ray exposure. Fewer than 5% of the 126 publications included in the literature review contained sufficient information to calculate dose and only 2.4% of the publications explicitly state an estimate of dose received by each sample. We conducted a study involving rice roots growing in soil, observing no significant difference between the numbers of root tips, root volume and total root length in scanned versus unscanned samples. In parallel, a soil microbe experiment scanning samples over a total of 24 weeks observed no significant difference between the scanned and unscanned microbial biomass values. We conclude from the literature review and our own experiments that X-ray CT does not impact plant growth or soil microbial populations when employing a low level of dose (<30 Gy. However, the call for higher throughput X-ray CT means that doses that biological samples receive are likely to increase and thus should be closely monitored.

  4. Lunar biological effects and the magnetosphere.

    Science.gov (United States)

    Bevington, Michael

    2015-12-01

    The debate about how far the Moon causes biological effects has continued for two millennia. Pliny the Elder argued for lunar power "penetrating all things", including plants, fish, animals and humans. He also linked the Moon with tides, confirmed mathematically by Newton. A review of modern studies of biological effects, especially from plants and animals, confirms the pervasive nature of this lunar force. However calculations from physics and other arguments refute the supposed mechanisms of gravity and light. Recent space exploration allows a new approach with evidence of electromagnetic fields associated with the Earth's magnetotail at full moon during the night, and similar, but more limited, effects from the Moon's wake on the magnetosphere at new moon during the day. The disturbance of the magnetotail is perhaps shown by measurements of electric fields of up to 16V/m compared with the usual electromagnetic radiation are known to affect animals and 10-20% of the human population. There is now evidence for mechanisms such as calcium flux, melatonin disruption, magnetite and cryptochromes. Both environmental and receptor variations explain confounding factors and inconsistencies in the evidence. Electromagnetic effects might also account for some evolutionary changes. Further research on lunar biological effects, such as acute myocardial infarction, could help the development of strategies to reduce adverse effects for people sensitive to geomagnetic disturbance. PMID:26462435

  5. Effective myofibroblast dedifferentiation by concomitant inhibition of TGF-beta signaling and perturbation of MAPK signaling

    Czech Academy of Sciences Publication Activity Database

    Kosla, Jan; Dvořáková, Marta; Dvořák, Michal; Čermák, Vladimír

    2013-01-01

    Roč. 92, č. 12 (2013), s. 363-373. ISSN 0171-9335 R&D Projects: GA AV ČR KAN200520801 Institutional support: RVO:68378050 Keywords : PDGFB * Ha-Ras(G12V) * EGR4 * TGF-beta * Myofibroblast * FOXG1 * Microarrays Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.699, year: 2013

  6. Estimation of beta-ray skin dose from exposure to fission fallout from the Hiroshima atomic bomb.

    Science.gov (United States)

    Endo, Satoru; Tanaka, Kenichi; Shizuma, Kiyoshi; Hoshi, Masaharu; Imanaka, Tetsuji

    2012-03-01

    Beta-ray skin dose due to the fission fallout from the Hiroshima atomic bomb is potentially related to the epilation in the black rain area. The absorbed dose to the skin from beta-rays emitted by fission fallout has been estimated for an initial ¹³⁷Cs deposition of 1 kBq m⁻² on the ground at 0.5 h after the explosion. The estimated skin dose takes into account both external exposure from fission fallout radionuclides uniformly distributed in 1 mm of soil on the surface of the ground and from a 26 μm thickness of contaminated soil on the skin, using the Monte Carlo radiation transport code MCNP-4C. The cumulative skin dose for 1 month after the explosion is taken as the representative value. The estimated skin dose for an initial ¹³⁷Cs deposition of 1 kBq m⁻² was determined to be about 500 mSv. PMID:22042969

  7. Effect of beta-escin sodium on endothelial cells proliferation, migration and apoptosis.

    Science.gov (United States)

    Wang, Xu-Hua; Xu, Bo; Liu, Jing-Tao; Cui, Jing-Rong

    2008-01-01

    beta-Escin, the major active compound in extracts of the horse chestnut Aesculus hippocastanum seed, has shown clinically significant activity in chronic venous insufficiency (CVI). Our previous studies had shown that beta-escin sodium inhibited angiogenesis in chick chorioallantoic membrane (CAM) and in aortic disk assay. In this study, we explored the direct effect of beta-escin sodium on proliferation, migration and apoptosis in human umbilical vein endothelial cells (HUVECs) and ECV304 cells. Sulforhodamine B (SRB) assay showed that beta-escin sodium (10, 20, 40 microg/ml) inhibited endothelial cells (ECs) proliferation dose-dependently. beta-escin sodium also induced ECs apoptosis at 40 microg/ml. Cell migration was evaluated by an improved wound assay: barren spot assay. And the direct effect on cell motility excluding influence of cell proliferation was examined by High Content Screening (HCS, Cellomics) assay. The data indicated that beta-escin sodium suppressed ECs migration and cell motility. Western blot results suggested that beta-escin sodium acts on ECs possibly by increasing expression of thrombospondin-1 (TSP-1), and decreasing expression of PKC-alpha and activation of p44/42 mitogen-activated protein kinase (ERK) and p38 mitogen-activated protein kinase (p38 MAPK). Our findings give the evidence that beta-escin sodium might have potential anti-angiogenic activity via its direct effects on ECs. PMID:18718875

  8. Investigation of the beta strength function at high energy: Gamma-ray spectroscopy of the decay of 5.3-s 84As to 84Se

    International Nuclear Information System (INIS)

    We have investigated the beta strength function up to approximately 8.6 MeV for the system 84As(β-)84Se. We find that it is not possible to satisfactorily describe Ssub(β) by a statistical model. From the 84As decay scheme we deduce an experimental beta strength function. Additional information on the beta transition intensity is obtained from the gross coincidence spectra of individual gamma rays. In total these data suggest that the experimental beta strength function above 6.8 MeV is significantly lower than that calculated using a statistical model. Features in the gross coincidence spectra also suggest that a significant bump appears in the experimental beta strength function at approximately 6.5 MeV. (orig.)

  9. Multifunctional cholinesterase and amyloid Beta fibrillization modulators. Synthesis and biological investigation.

    Science.gov (United States)

    Butini, Stefania; Brindisi, Margherita; Brogi, Simone; Maramai, Samuele; Guarino, Egeria; Panico, Alessandro; Saxena, Ashima; Chauhan, Ved; Colombo, Raffaella; Verga, Laura; De Lorenzi, Ersilia; Bartolini, Manuela; Andrisano, Vincenza; Novellino, Ettore; Campiani, Giuseppe; Gemma, Sandra

    2013-12-12

    In order to identify novel Alzheimer's modifying pharmacological tools, we developed bis-tacrines bearing a peptide moiety for specific interference with surface sites of human acetylcholinesterase (hAChE) binding amyloid-beta (Aβ). Accordingly, compounds 2a-c proved to be inhibitors of hAChE catalytic and noncatalytic functions, binding the catalytic and peripheral sites, interfering with Aβ aggregation and with the Aβ self-oligomerization process (2a). Compounds 2a-c in complex with TcAChE span the gorge with the bis-tacrine system, and the peptide moieties bulge outside the gorge in proximity of the peripheral site. These moieties are likely responsible for the observed reduction of hAChE-induced Aβ aggregation since they physically hamper Aβ binding to the enzyme surface. Moreover, 2a was able to significantly interfere with Aβ self-oligomerization, while 2b,c showed improved inhibition of hAChE-induced Aβ aggregation. PMID:24900626

  10. Boundary Electron and Beta Dosimetry-Quantification of the Effects of Dissimilar Media on Absorbed Dose

    Science.gov (United States)

    Nunes, Josane C.

    1991-02-01

    This work quantifies the changes effected in electron absorbed dose to a soft-tissue equivalent medium when part of this medium is replaced by a material that is not soft -tissue equivalent. That is, heterogeneous dosimetry is addressed. Radionuclides which emit beta particles are the electron sources of primary interest. They are used in brachytherapy and in nuclear medicine: for example, beta -ray applicators made with strontium-90 are employed in certain ophthalmic treatments and iodine-131 is used to test thyroid function. More recent medical procedures under development and which involve beta radionuclides include radioimmunotherapy and radiation synovectomy; the first is a cancer modality and the second deals with the treatment of rheumatoid arthritis. In addition, the possibility of skin surface contamination exists whenever there is handling of radioactive material. Determination of absorbed doses in the examples of the preceding paragraph requires considering boundaries of interfaces. Whilst the Monte Carlo method can be applied to boundary calculations, for routine work such as in clinical situations, or in other circumstances where doses need to be determined quickly, analytical dosimetry would be invaluable. Unfortunately, few analytical methods for boundary beta dosimetry exist. Furthermore, the accuracy of results from both Monte Carlo and analytical methods has to be assessed. Although restricted to one radionuclide, phosphorus -32, the experimental data obtained in this work serve several purposes, one of which is to provide standards against which calculated results can be tested. The experimental data also contribute to the relatively sparse set of published boundary dosimetry data. At the same time, they may be useful in developing analytical boundary dosimetry methodology. The first application of the experimental data is demonstrated. Results from two Monte Carlo codes and two analytical methods, which were developed elsewhere, are compared

  11. Effect of Beta-Hydroxy Beta-Methylbutyrate on the Onset of Blood Lactate Accumulation and VO2peak in Endurance-Trained Cyclists.

    Science.gov (United States)

    Vukovich, Matthew D.; Dreifort, Geri D.

    2001-01-01

    Examined the effect of beta-hydroxy beta-methylbutyrate (HMB) supplementation on maximal oxygen consumption (VO2peak) and onset of blood lactate accumulation (OBLA) in endurance-trained cyclists. Acute exercise did not affect plasma HMB concentrations. OBLA increased with HMB and leucine, with blood glucose significantly greater during the HMB…

  12. Solvent effects in TLS determination of beta-lactoglobulin

    International Nuclear Information System (INIS)

    Accidental presence of small quantities of different allergens such as beta-lactoglobulin in food products is a problem for unaware allergic consumers. Therefore, sensitive methods are needed for detection of trace quantities of allergens. By implementing TLS detection into a FIA system, the sensitivity of beta-lactoglobulin detection was improved. The use of different solvents in the FIA system, however, causes perturbations in the TLS signals. The aim of this research was to reduce the influence of spurious signals and to improve the detection limits of the analytical assay. The optimal performance of the FIA-TLS system for beta-lactoglobulin determination was achieved by using PBS buffer solutions (pH 7.5), which resulted in lowest limits of detection of 2 pM BLG and the total assay time of 10 min.

  13. Astrophysical and Biological Implications of $\\gamma$-Ray Burst Properties

    CERN Document Server

    Scalo, J M; Scalo, John

    1999-01-01

    Combining results from Schmidt (1999) for the local cosmic rate and mean peakluminosity of gamma-ray bursts (GRBs) with recent work on the history of thecosmic star formation rate, we provide estimates for the local GRB rate perunit blue luminosity in galaxies. These values are used to examine a number ofphenomena with the following conclusions: 1) The ratio of supernova rate to GRBrate is so large that it is difficult to maintain that more than a smallfraction of neutron star or black hole-forming events produced GRBs, evenallowing for generous collimation; 2) The GRB rate is so small that it isimpossible to use these events to account for the majority of large HI holesobserved in our own and other galaxies; the expected number of holes is muchsmaller than observed; 3) Modeling the GRB events in the Milky Way as a spatialPoisson process and allowing for modest enhancement in the star formation ratedue to birth in a spiral arm, we find that the probability that the solarsystem was exposed to a fluence large e...

  14. Application of X ray fluorescence techniques for the determination of hazardous and essential trace elements in environmental and biological materials

    International Nuclear Information System (INIS)

    Full text: The utilization of X ray fluorescence (XRF) technique for the determination of trace element concentrations in environmental and biological samples is presented. The analytical methods used include energy dispersive X ray fluorescence (EDXRF), total reflection X ray fluorescence (TXRF), micro-beam X ray fluorescence and direct in situ X-ray fluorescence analysis. The measurements have been performed with X ray tube- and radioisotope-based energy dispersive X ray fluorescence spectrometers. Both liquid nitrogen- and thermo electrically-cooled silicon detectors were utilized in the analysis. Samples analysed include soil, water, plant material, and airborne particulate matter collected on filters. Depending on the technique and the investigated elements, the above-mentioned samples were analysed either directly or indirectly (after decomposing the sample in a mineralization process or/and chemical preconcentration procedure). The achieved detection limits for different techniques, established by measuring appropriate reference standards, are presented. The utilization of the micro-beam XRF technique for studying element distribution in heterogeneous samples and investigating the 3D- and 2D-morphology of minute samples by means of computerized X ray absorption and X ray fluorescence tomography is described. The different X ray techniques have their unique advantages. The micro-beam X ray fluorescence set-up has an advantage of producing very well collimated primary X ray beam (by means of X ray capillary optics the beam is collimated down to about 15 μm in diameter), in front of which the analysed sample can be precisely positioned, providing local information about the sample composition. TXRF technique has its leading edge in analysis of liquid samples, and as a reference method for a conventional bulk EDXRF analysis of heterogeneous materials such as air particulates collected on filter where the particle size effects can seriously influence the

  15. The non-haematopoietic biological effects of erythropoietin.

    Science.gov (United States)

    Arcasoy, Murat O

    2008-04-01

    In the haematopoietic system, the principal function of erythropoietin (Epo) is the regulation of red blood cell production, mediated by its specific cell surface receptor (EpoR). Following the cloning of the Epo gene (EPO) and characterization of the selective haematopoietic action of Epo in erythroid lineage cells, recombinant Epo forms (epoetin-alfa, epoetin-beta and the long-acting analogue darbepoetin-alfa) have been widely used for treatment of anaemia in chronic kidney disease and chemotherapy-induced anaemia in cancer patients. Ubiquitous EpoR expression in non-erythroid cells has been associated with the discovery of diverse biological functions for Epo in non-haematopoietic tissues. During development, Epo-EpoR signalling is required not only for fetal liver erythropoiesis, but also for embryonic angiogenesis and brain development. A series of recent studies suggest that endogenous Epo-EpoR signalling contributes to wound healing responses, physiological and pathological angiogenesis, and the body's innate response to injury in the brain and heart. Epo and its novel derivatives have emerged as major tissue-protective cytokines that are being investigated in the first human studies involving neurological and cardiovascular diseases. This review focuses on the scientific evidence documenting the biological effects of Epo in non-haematopoietic tissues and discusses potential future applications of Epo and its derivatives in the clinic. PMID:18324962

  16. Mechanistic Effects of Calcitriol in Cancer Biology

    Directory of Open Access Journals (Sweden)

    Lorenza Díaz

    2015-06-01

    Full Text Available Besides its classical biological effects on calcium and phosphorus homeostasis, calcitriol, the active vitamin D metabolite, has a broad variety of actions including anticancer effects that are mediated either transcriptionally and/or via non-genomic pathways. In the context of cancer, calcitriol regulates the cell cycle, induces apoptosis, promotes cell differentiation and acts as anti-inflammatory factor within the tumor microenvironment. In this review, we address the different mechanisms of action involved in the antineoplastic effects of calcitriol.

  17. Proton-Induced X-ray Emission (PIXE Analysis and DNA-chain Break study in rat hepatocarcinogenesis: A possible chemopreventive role by combined supplementation of vanadium and beta-carotene

    Directory of Open Access Journals (Sweden)

    Kanjilal NB

    2005-05-01

    Full Text Available Abstract Combined effect of vanadium and beta-carotene on rat liver DNA-chain break and Proton induced X-ray emission (PIXE analysis was studied during a necrogenic dose (200 mg/kg of body weight of Diethyl Nitrosamine (DENA induced rat liver carcinogenesis. Morphological and histopathological changes were observed as an end point biomarker. Supplementation of vanadium (0.5 ppm ad libitum in drinking water and beta-carotene in the basal diet (120 mg/Kg of body weight were performed four weeks before DENA treatment and continued till the end of the experiment (16 weeks. PIXE analysis revealed the restoration of near normal value of zinc, copper, and iron, which were substantially altered when compared to carcinogen treated groups. Supplementation of both vanadium and beta-carotene four weeks before DENA injection was found to offer significant (64.73%, P

  18. THz waves: biological effects, industrial and medical

    International Nuclear Information System (INIS)

    Following the debates about body scanners installed in airports for passengers security control, the non-ionizing radiations (NIR) section of the French radiation protection society (SFR) has organized a conference day to take stock of the present day knowledge about the physical aspects and the biological effects of this frequency range as well as about their medical, and industrial applications (both civil and military). This document gathers the slides of the available presentations: 1 - introduction and general considerations about THz waves, the THz physical phenomenon among NIR (J.L. Coutaz); 2 - interaction of millimeter waves with living material: from dosimetry to biological impacts (Y. Le Drean and M. Zhadobov); 3 - Tera-Hertz: standards and recommendations (B. Veyret); 4 - THz spectro-imaging technique: status and perspectives (P. Mounaix); 5 - THz technology: seeing the invisible? (J.P. Caumes); 6 - Tera-Hertz: biological and medical applications (G. Gallot); 7 - Biological applications of THz radiation: a review of events and a glance to the future (G.P. Gallerano); 8 - Industrial and military applications - liquids and solids detection in the THz domain (F. Garet); 9 - THz radiation and its civil and military applications - gas detection and quantifying (G. Mouret); 10 - Body scanners and civil aviation security (J.C. Guilpin, presentation not available). (J.S.)

  19. Effects of short-hairpin RNA-inhibited {beta}-catenin expression on the growth of human multiple myeloma cells in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Wenqing, E-mail: liangwenqing_1234@126.com [Department of Orthopaedics, Shaoxing People' s Hospital, 568 Zhongxing North Road, Shaoxing 312000 (China); Yang, Chengwei [Department of Spinal Surgery, Lanzhou General Hospital, Lanzhou Military Area Command, 333 Nanbinhe Road, Lanzhou 730050 (China); Qian, Yu [Department of Orthopaedics, Shaoxing People' s Hospital, 568 Zhongxing North Road, Shaoxing 312000 (China); Fu, Qiang, E-mail: chyygklwq@hotmail.com [Department of Orthopaedics, Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai 200433 (China)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer {beta}-Catenin expression were markedly down-regulated by CTNNB1 shRNA. Black-Right-Pointing-Pointer CTNNB1 shRNA could inhibit the proliferation of RPMI8226 cells. Black-Right-Pointing-Pointer Significantly profound apoptotic cell death in CTNNB1 shRNA cells. Black-Right-Pointing-Pointer In vivo, CTNNB1 silence led to a growth inhibition of myeloma growth. Black-Right-Pointing-Pointer c-myc and {beta}-catenin in the expression cells of cleaved caspase-3 were increased. -- Abstract: Multiple myeloma (MM) is thrombogenic as a consequence of multiple hemostatic effects. Overexpression of {beta}-catenin has been observed in several types of malignant tumors, including MM. However, the relationship between {beta}-catenin expression and MM remains unclear. In the present study, RNA interference was used to inhibit {beta}-catenin expression in RPMI8226 cells. RT-PCR and Western blotting analyses showed that {beta}-catenin mRNA and protein expression were markedly down-regulated by CTNNB1 shRNA. Western blotting showed that the protein levels of cyclin D1 and glutamine synthetase were downregulated and supported the transcriptional regulatory function of {beta}-catenin. The MTT assay showed that CTNNB1 shRNA could have significant inhibitory effects on the proliferation of RPMI8226 cells. The TOPflash reporter assay demonstrated significant downregulation after CTNNB1 shRNA transfection in RPMI8226 cells. Flow cytometric analyses also showed significantly profound apoptosis in CTNNB1 shRNA cells. We found CTNNB1 silence led to growth inhibition of MM growth in vivo. Immunohistochemical analyses showed that c-myc and {beta}-catenin were reduced in CTNNB1 shRNA tumor tissues, but that expression of cleaved caspase-3 was increased. These results show that {beta}-catenin could be a new therapeutic agent that targets the biology of MM cells.

  20. Effect of Disturbance Regime on Alpha and Beta Diversity of Rock Pools

    Directory of Open Access Journals (Sweden)

    Annie Séguin

    2013-12-01

    Full Text Available Measures of alpha diversity are more frequently used to detect environmental changes and subsequent impacts on biodiversity, while measures based on variability (beta diversity are said to be more appropriate for detecting those impacts. Theory predicts that beta diversity should increase with disturbance frequency in patchy communities. Our objective in this study was to experimentally determine the effect of high and low disturbance regimes, frequency and intensity combined, on marine benthic alpha and beta diversity. The experiment was conducted in a rock pool system of the St. Lawrence estuary, Canada. Rock pools were disturbed by (1 nutrient enrichment and (2 draining according to three disturbance regimes (none, low, high. Disturbance regimes had little or no effect on alpha diversity of benthic algae and sessile animals. However, the low regime of nutrient enrichment induced greater within-group beta diversity than the reference rock pools, while the high disturbance regime induced equal or even smaller within-group beta diversity compared to the reference. Draining had an opposite effect on benthic beta diversity, with a greater variability of the community structure under the high regime of disturbance. Taking into account the effect of disturbance regimes on beta diversity could provide a useful diagnostic for disturbed benthic communities.

  1. Central effects of beta-endorphins on glucose homeostasis in the conscious dog

    International Nuclear Information System (INIS)

    The effects of centrally administered beta-endorphins on glucose homeostasis in the conscious dog were studied. Intracerebroventricular administration of beta-endorphin (0.2 mg/h) caused a 70% increase in plasma glucose. The mechanism of the hyperglycemia was twofold: there was an early increase in glucose production and a late inhibition of glucose clearance. These changes are explained by marked increases in plasma epinephrine (30-fold) and norepinephrine (6-fold) that occurred during infusion of beta-endorphin. Central administration of beta-endorphin also resulted in increased levels of adrenocorticotropic hormone and cortisol. In addition there was an increase in plasma insulin but no increase in plasma glucagon. Intravenous administration of beta-endorphin did not alter glucose homeostasis. Intracerebroventricular administration of acetylated beta-endorphin did not perturb glucose kinetics or any of the hormones that changed during infusion of the unacetylated peptide. We conclude that beta-endorphin acts centrally to cause hyperglycemia by stimulating sympathetic outflow and the pituitary-adrenal axis. Acetylation of beta-endorphin abolishes the in vivo activity of the peptide

  2. Simultaneous beta/gamma digital spectroscopy

    Science.gov (United States)

    Farsoni, Abdollah T.

    A state-of-the-art radiation detection system for simultaneous spectroscopy of beta-particles and gamma-rays has been developed. The system utilizes a triple-layer phoswich detector and a customized Digital Pulse Processor (DPP) built in our laboratory. The DPP board was designed to digitally capture the analog signal pulses and, following several digital preprocessing steps, transfer valid pulses to the host computer for further digital processing. A MATLAB algorithm was developed to digitally discriminate beta and gamma events and reconstruct separate beta and gamma-ray energy spectra with minimum crosstalk. The spectrometer proved to be an effective tool for recording separate beta and gamma-ray spectra from mixed radiation fields. The system as a beta-gamma spectrometer will have broad-ranging applications in nuclear non-proliferation, radioactive waste management, worker safety, systems reliability, dose assessment, and risk analysis.

  3. Non-stochastic effects of different energy beta emitters on pig and mouse skin

    International Nuclear Information System (INIS)

    In this collaborative study skin areas of various sizes were irradiated with different energy beta emitters. In the post-irradiation period fields were examined for erythema, desquamation, ulceration and dermal necrosis. The aim of the study is to determine the threshold doses for the different biological reactions as a function of the energy of the radiation and the size of skin field irradiated. At St. Bartholomew's Hospital and Oxford the irradiation of mouse and pig skin was carried out using strontium-90 and thulium-170 sources. In addition, mice were irradiated with thallium-204, a slightly lower energy beta emitter than thulium. (author)

  4. X-ray spectrometric determination of thorium in bone and other biological materials

    International Nuclear Information System (INIS)

    An x-ray spectrometric method has been developed for the determination of thorium in bone and other biological materials. The limit of detection at the 95% confidence level is 20 ng. This corresponds to a concentration of 2 ppb in a 10-g sample of bone ash

  5. Electronprobe X-ray microanalysis of biological specimens improvement of a number of quantification procedures

    International Nuclear Information System (INIS)

    In this thesis an investigation is described to establish which quantification procedures can be used in the X-ray microanalysis of biological specimens. Two classes of specimens have been distinguished from each other, i.e. thick specimens (opaque to the beam electrons) and thin specimens (transparent to the beam electrons). (Auth.)

  6. Elemental analysis of biological samples using deuteron induced X-rays and charged particles

    International Nuclear Information System (INIS)

    A method for elemental analysis in biological samples is presented. Samples were exposed to 4 MeV deuterons and both charged particle and X-ray spectra were recorded. The method was tested on a biopsi of mouseliver and a blood-serum-sample and was found promising for rapid analysis of samples associated with small amounts of material (μg). (Auth.)

  7. The acute effects of alpha and beta irradiation of mouse skin and the factors affecting the response

    International Nuclear Information System (INIS)

    Several problems regarding acute effects of alpha and beta irradiation were investigated in order to clarify protection problems of localised doses to the skin. A study into the acute biological effects of different energy beta emitters and the effects of energy and area on the response showed direct relationships between these criteria for a range of different acute responses with different time courses. Three different types of acute response were found and these are described as 'moist desquamation', 'acute ulceration' and 'acute epidermal necrosis'. An unexpected finding was that the lower energy beta emitter 170Tm was as efficient at inducing scab formation as the higher energy 90Sr sources for the same area of exposure. Experiments using 2x4 cm2 exposures to 224Cm alpha particles showed that the response to this poorly penetrating radiation was minimal after doses as high as 180 Gy measured at 10 μm into the skin. In comparison, large area exposure to 170Tm produced areas of prolonged scabbing after doses up to 100 Gy. However, the intensity of the reaction varied between strains. (author)

  8. Effects of purified dietary fiber sources on beta-carotene utilization by the chick.

    Science.gov (United States)

    Erdman, J W; Fahey, G C; White, C B

    1986-12-01

    Effects of various purified dietary fiber components on beta-carotene utilization by the chick were investigated in two experiments (expt.). Eight-day-old Columbian X New Hampshire male (expt. 1) or female (expt. 2) chicks were fed a vitamin A-deficient diet for 1 wk and then fed beta-carotene-supplemented diets containing 0% fiber, 7% arenaceous flour or 7% of a purified fiber source for 4 wk. Results of expt. 1 showed that hemicellulose, lignin and citrus pectin, but not arenaceous flour or polygalacturonic acid, depressed beta-carotene utilization by the chick, as measured by percentage of consumed beta-carotene stored in liver as vitamin A relative to the 0% fiber control. In expt. 2, effects of the methoxyl content of pectin were studied. High and medium methoxyl apple pectin, citrus pectin and polygalacturonic acid reduced storage of vitamin A in liver. Low methoxyl apple pectin had no significant effect on beta-carotene utilization. Thus, several purified forms of dietary fiber significantly reduced beta-carotene utilization by chicks when fed at the 7% supplementary level. Moreover, with pectin, there was an inverse relationship between methoxyl content of pectin and beta-carotene utilization. PMID:3027282

  9. Quantitative and dynamic measurements of biological fresh samples with X-ray phase contrast tomography

    International Nuclear Information System (INIS)

    Quantitative measurements of biological fresh samples based on three-dimensional densitometry using X-ray phase contrast tomography are presented. X-ray phase contrast tomography using a Talbot grating interferometer was applied to biological fresh samples which were not fixed by any fixatives. To achieve a high-throughput measurement for the fresh samples the X-ray phase contrast tomography measurement procedure was improved. The three-dimensional structure of a fresh mouse fetus was clearly depicted as a mass density map using X-ray phase contrast tomography. The mouse fetus measured in the fresh state was then fixed by formalin and measured in the fixed state. The influence of the formalin fixation on soft tissue was quantitatively evaluated by comparing the fresh and fixed samples. X-ray phase contrast tomography was also applied to the dynamic measurement of a biological fresh sample. Morphological changes of a ring-shaped fresh pig aorta were measured tomographically under different degrees of stretching

  10. Quantitative and dynamic measurements of biological fresh samples with X-ray phase contrast tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Masato, E-mail: hoshino@spring8.or.jp; Uesugi, Kentaro [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Tsukube, Takuro [Japanese Red Cross Kobe Hospital, 1-3-1 Wakinohamakaigandori, Chuo-ku, Kobe, Hyogo 651-0073 (Japan); Yagi, Naoto [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2014-10-08

    Quantitative measurements of biological fresh samples based on three-dimensional densitometry using X-ray phase contrast tomography are presented. X-ray phase contrast tomography using a Talbot grating interferometer was applied to biological fresh samples which were not fixed by any fixatives. To achieve a high-throughput measurement for the fresh samples the X-ray phase contrast tomography measurement procedure was improved. The three-dimensional structure of a fresh mouse fetus was clearly depicted as a mass density map using X-ray phase contrast tomography. The mouse fetus measured in the fresh state was then fixed by formalin and measured in the fixed state. The influence of the formalin fixation on soft tissue was quantitatively evaluated by comparing the fresh and fixed samples. X-ray phase contrast tomography was also applied to the dynamic measurement of a biological fresh sample. Morphological changes of a ring-shaped fresh pig aorta were measured tomographically under different degrees of stretching.

  11. Development of laser plasma x-ray microscope for living hydrated biological specimens

    International Nuclear Information System (INIS)

    Investigating the structure and the function of life object performing advanced life activity becomes important. In order to investigate the life object, it is necessary to observe living specimens with high spatial resolution and high temporal resolution. Since laser plasma x-ray source has high brightness and short pulse duration, x-ray microscope with the laser plasma x-ray source makes possible to observe living specimens. Such as chromosomes, macrophages, bacterium, and so on have been observed by contact x-ray microscopy. The x-ray images obtained by indirect measurements such as the contact x-ray microscopy have difficulty to avoid artificial effect such as irregular due to developing process. Development of an x-ray microscope with laser plasma x-ray source is necessary to avoid such defects. (author)

  12. Expression, purification, crystallization and preliminary X-ray analysis of Aeromonas hydrophilia metallo-[beta]-lactamase

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, N.; Toney, J.H.; Fitzgerald, P.M.D. (Merck)

    2010-07-20

    The CphA metallo-{beta}-lactamase from Aeromonas hydrophilia has been expressed, purified and crystallized by the hanging-drop vapor-diffusion method using ammonium sulfate as the precipitant. The crystals exhibit orthorhombic symmetry (P2{sub 1}2{sub 1}2), with unit-cell parameters a = 40.75, b = 42.05, c = 128.88 {angstrom}. There is one monomer in the asymmetric unit and the solvent content is estimated to be 44% by volume. A data set extending to 1.8 {angstrom} has been measured.

  13. Microwave radiation - Biological effects and exposure standards

    Energy Technology Data Exchange (ETDEWEB)

    Lindsay, I.R.

    1980-06-01

    The thermal and nonthermal effects of exposure to microwave radiation are discussed and current standards for microwave exposure are examined in light of the proposed use of microwave power transmission from solar power satellites. Effects considered include cataractogenesis at levels above 100 mW/sq cm, and possible reversible disturbances such as headaches, sleeplessness, irritability, fatigue, memory loss, cardiovascular changes and circadian rhythm disturbances at levels less than 10 mW/sq cm. It is pointed out that while the United States and western Europe have adopted exposure standards of 10 mW/sq cm, those adopted in other countries are up to three orders of magnitude more restrictive, as they are based on different principles applied in determining safe limits. Various aspects of the biological effects of microwave transmissions from space are considered in the areas of the protection of personnel working in the vicinity of the rectenna, interactions of the transmitted radiation with cardiac pacemakers, and effects on birds. It is concluded that thresholds for biological effects from short-term microwave radiation are well above the maximal power density of 1 mW/sq cm projected at or beyond the area of exclusion of a rectenna.

  14. Monte Carlo Models for the Production of beta-delayed Gamma Rays Following Fission of Special Nuclear Materials

    Energy Technology Data Exchange (ETDEWEB)

    Pruet, J; Prussin, S; Descalle, M; Hall, J

    2004-02-03

    A Monte Carlo method for the estimation of {beta}-delayed {gamma}-ray spectra following fission is described that can accommodate an arbitrary time-dependent fission rate and photon collection history. The method invokes direct sampling of the independent fission yield distributions of the fissioning system, the branching ratios for decay of individual fission products and the spectral distributions for photon emission for each decay mode. Though computationally intensive, the method can provide a detailed estimate of the spectrum that would be recorded by an arbitrary spectrometer, and can prove useful in assessing the quality of evaluated data libraries, for identifying gaps in these libraries, etc. The method is illustrated by a first comparison of calculated and experimental spectra from decay of short-lived fission products following the reactions {sup 235}U(n{sub th}, f) and {sup 239}Pu(n{sub th}, f). For general purpose transport calculations, where detailed consideration of the large number of individual {gamma}-ray transitions in a spectrum may be unnecessary, it is shown that an accurate and simple parameterization of a {gamma}-ray source function can be obtained. These parametrizations should provide high-quality average spectral distributions that should prove useful in calculations describing photons escaping from thick attenuating media.

  15. Effect of copper (II) ion against elongation behavior of amyloid {beta} fibrils on liposome membranes

    Energy Technology Data Exchange (ETDEWEB)

    Shimanouchi, T.; Onishi, R.; Kitaura, N.; Umakoshi, H.; Kuboi, R. [Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka (Japan)

    2012-01-15

    The fibril growth behavior of amyloid {beta} protein (A{beta}) on cell membranes is relating to the progression of Alzheimer's disease. This growth behavior of A{beta} fibrils is sensitively affected by the metal ions, neurotransmitters, or bioreactive substrate. The inhibitory effect of those materials was quantitatively estimated from the viewpoints of ''crystal growth''. In a bulk aqueous solution, copper (II) ion showed the strong inhibitory effect on the growth of A{beta} fibrils. Meanwhile, the addition of a closed-phospholipid bilayer membrane (liposome) could reduce the above inhibitory effect of copper (II) ion. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. A novel method to determine Poisson's ratio by beta-ray absorption experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fathi, Jafar [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz 51666 (Iran, Islamic Republic of); Ashrafi, Saleh [Department of Nuclear Physics, Faculty of Physics, University of Tabriz, Tabriz 51666 (Iran, Islamic Republic of); Movla, Hossein [Department of Solid State Physics, Faculty of Physics, University of Tabriz, Tabriz 51666 (Iran, Islamic Republic of); Sobhaian, Samad, E-mail: sobhanian@tabrizu.ac.ir [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz 51666 (Iran, Islamic Republic of)

    2012-05-15

    In this paper a new experimental method is applied to determine Poisson's ratio of an industrial rubber tape based on the attenuation of beta particles. A simple theoretical model is presented and the experimental results are compared with the model's prediction. Poisson's ratio of the rubber is obtained by applying a steady state strain force. The relatively good agreement between the model's prediction and the experimental results could be a verification test for the presented method. - Highlights: Black-Right-Pointing-Pointer This paper indicates a novel method to determine Poisson's ratio by beta absorption. Black-Right-Pointing-Pointer A simple model is presented and the experimental results are compared with its prediction. Black-Right-Pointing-Pointer The method utilizes typical values in defining properties such as Young's modulus. Black-Right-Pointing-Pointer Good agreement is obtained between the model's prediction and the experimental results.

  17. An X-ray diffraction procedure for the estimation of the alpha and beta polymorph proportion in sintered silicon carbide

    International Nuclear Information System (INIS)

    The use of X-ray powder diffraction for the determination of the proportions of the alpha and beta polymorphs in the sintered silicon carbide of furnace elements has been investigated. There are several α-SiC reflections without β-SiC counterparts but no unique β-SiC reflection. An internal ratio method cannot therefore be employed and direct reliance must be placed on the intensity change of distinctive α-SiC peaks with progressive β-SiC dilution. Uniformity of sample preparation, sample presentation and machine operating conditions during calibration and subsequent application is therefore essential. The 0.266 nm α-SiC peak was selected for use in calibration as it is readily discriminated above a relatively flat background even at low levels of α-SiC in mixtures of the two polymorphs. (author)

  18. Collective Effect Studies of a Beta Beam Decay Ring

    CERN Document Server

    Hansen, Christian

    2011-01-01

    The Beta Beam, the concept of generating a pure and intense (anti) neutrino beam by letting accelerated radioactive ions beta decay in a storage ring called the Decay Ring (DR), is the basis of one of the proposed next generation neutrino oscillation facilities, necessary for a complete study of the neutrino oscillation parameter space. Sensitivities of the unknown neutrino oscillation parameters depend on the DR's ion intensity and of its duty factor (the filled ratio of the ring). Different methods, including analytical calculations and multiparticle tracking simulations, were used to estimate the DR's potential to contain enough ions in as small a part of the ring as needed for the sensitivities. Studies of transverse blow up of the beams due to resonance wake fields show that a very challenging upper limit of the transverse broadband impedance is required to avoid instabilities and beam loss.

  19. Collective Effect Studies of a Beta Beam Decay Ring

    International Nuclear Information System (INIS)

    The Beta Beam, the concept of generating a pure and intense (anti) neutrino beam by letting accelerated radioactive ions beta decay in a storage ring called the Decay Ring (DR), is the basis of one of the proposed next generation neutrino oscillation facilities, necessary for a complete study of the neutrino oscillation parameter space. Sensitivities of the unknown neutrino oscillation parameters depend on the DR's ion intensity and of its duty factor (the filled ratio of the ring). Different methods, including analytical calculations and multiparticle tracking simulations, were used to estimate the DR's potential to contain enough ions in as small a part of the ring as needed for the sensitivities. Studies of transverse blow up of the beams due to resonance wake fields show that a very challenging upper limit of the transverse broadband impedance is required to avoid instabilities and beam loss.

  20. Plans for production of undulator X-rays on AR and its applications to material and biological sciences

    International Nuclear Information System (INIS)

    This report carries 19 studies. The first two describe 'Hope for Andulator X-Rays' and 'A Plan for Application of AR Synchrotron Radiation Beam'. Three studies on undulator X-rays are presented, which are entitled 'Development of X-Ray Undulator', 'AR-BL-NE Triple Beamline' and 'Fluctuations of Synchrotron Radiation Beam Position and Development of a Beam Position Feedback System for a Beamline of the TRISTAN Accumulation Ring'. Two studies on application to Moessbauer X-rays are contained, which are entitled 'Nuclear Resonant Scattering of Synchrotron Radiation X-Rays' and 'Biological Action of Moessbauer Effect -- Feasibility of Application to Treatment of Cancer'. Two studies on application to research on surface and interface are addressed, which are entitled 'Application to Research on Surface and Interface; Research by Diffraction' and 'How Can Compton Scattering Serve for Study on Surface Layer?'. Five studies on the application to research on submicron crystal structure' are presented, which are entitled Application to Research on Submicron Crystal Structure; Inorganic and Mineral Substances', 'Comments on Application to Research on Submicron Crystal Structure', etc. The report also contains two studies on abnormal scattering and three studies on microbeam X-rays. (N.K.)

  1. Biological effect of low dose radiation

    International Nuclear Information System (INIS)

    This document describes the recent findings in studies of low dose radiation effect with those by authors' group. The low dose radiation must be considered in assessment of radiation effects because it induces the biological influence unexpected hitherto; i.e., the bystander effect and genetic instability. The former is a non-targeted effect that non-irradiated cells undergo the influence of directly irradiated cells nearby, which involves cell death, chromosome aberration, micronucleus formation, mutation and carcinogenesis through cellular gap junction and/or by signal factors released. Authors' group has found the radical(s) possessing as long life time as >20 hr released from the targeted cells, a possible mediator of the effect; the generation of aneuploid cells as an early carcinogenetic change; and at dose level <10 Gy, activation of MAPK signal pathway leading to relaxation of chromatin structure. The genetic instability means the loss of stability where replication and conservation of genome are normally maintained, and is also a cause of the late radiation effect. The group has revealed that active oxygen molecules can affect the late effect like delayed cell death, giant cell formation and chromosome aberration, all of which lead to the instability, and is investigating the hypothesis that the telomere instability resulted from the abnormal post-exposure interaction with its nuclear membrane or between chromatin and nuclear matrix, is enhanced by structural distortion of nuclear genes. As well, shown is the possible suppression of carcinogenesis by p53. The group, to elucidate the mechanism underlying the low dose radiation effect, is conducting their studies in consideration of the sequential bases of physical, chemical and biological processes. (R.T.)

  2. Haemopoietic effects of 7 alpha, 17 beta dimethyltestosterone

    International Nuclear Information System (INIS)

    Some haematic parameters were investigated in female COBS mice treated with 7 alpha, 17 beta Dimethyltestosterone (DMT). The drug causes an increase of circulating platelets in normal mice. Bone marrow graft from DMT-treated donors facilitates in irradiated mice repopulation of white blood cells and platelets but lowers % survival. These data are interpreted on the basis of a 'commitment' and a loss of self-maintenance induced by DMT on CFUs compartment. (author)

  3. High resolution x-ray microtomography of biological samples: Requirements and strategies for satisfying them

    Energy Technology Data Exchange (ETDEWEB)

    Loo, B.W. Jr. [Univ. of California, San Francisco, CA (United States)]|[Univ. of California, Davis, CA (United States)]|[Lawrence Berkeley National Lab., CA (United States); Rothman, S.S. [Univ. of California, San Francisco, CA (United States)]|[Lawrence Berkeley National Lab., CA (United States)

    1997-02-01

    High resolution x-ray microscopy has been made possible in recent years primarily by two new technologies: microfabricated diffractive lenses for soft x-rays with about 30-50 nm resolution, and high brightness synchrotron x-ray sources. X-ray microscopy occupies a special niche in the array of biological microscopic imaging methods. It extends the capabilities of existing techniques mainly in two areas: a previously unachievable combination of sub-visible resolution and multi-micrometer sample size, and new contrast mechanisms. Because of the soft x-ray wavelengths used in biological imaging (about 1-4 nm), XM is intermediate in resolution between visible light and electron microscopies. Similarly, the penetration depth of soft x-rays in biological materials is such that the ideal sample thickness for XM falls in the range of 0.25 - 10 {mu}m, between that of VLM and EM. XM is therefore valuable for imaging of intermediate level ultrastructure, requiring sub-visible resolutions, in intact cells and subcellular organelles, without artifacts produced by thin sectioning. Many of the contrast producing and sample preparation techniques developed for VLM and EM also work well with XM. These include, for example, molecule specific staining by antibodies with heavy metal or fluorescent labels attached, and sectioning of both frozen and plastic embedded tissue. However, there is also a contrast mechanism unique to XM that exists naturally because a number of elemental absorption edges lie in the wavelength range used. In particular, between the oxygen and carbon absorption edges (2.3 and 4.4 nm wavelength), organic molecules absorb photons much more strongly than does water, permitting element-specific imaging of cellular structure in aqueous media, with no artifically introduced contrast agents. For three-dimensional imaging applications requiring the capabilities of XM, an obvious extension of the technique would therefore be computerized x-ray microtomography (XMT).

  4. Determining the Effect of Aluminum Oxide Nanoparticles on the Aggregation of Amyloid-Beta in Transgenic Caenorhabditis elegans

    Science.gov (United States)

    Patel, Suhag; Matticks, John; Howell, Carina

    2014-03-01

    The cause of Alzheimer's disease has been linked partially to genetic factors but the predicted environmental components have yet to be determined. In Alzheimer's, accumulation of amyloid-beta protein in the brain forms plaques resulting in neurodegeneration and loss of mental functions. It has been postulated that aluminum influences the aggregation of amyloid-beta. To test this hypothesis, transgenic Caenorhabditis elegans, CL2120, was used as a model organism to observe neurodegeneration in nematodes exposed to aluminum oxide nanoparticles. Behavioral testing, fluorescent staining, and fluorescence microscopy were used to test the effects of aggregation of amyloid-beta in the nervous systems of effected nematodes exposed to aluminum oxide nanoparticles. Energy-dispersive x-ray spectroscopy was used to quantify the total concentration of aluminum oxide that the worms were exposed to during the experiment. Exposure of transgenic and wild type worms to a concentration of 4 mg mL-1 aluminum oxide showed a decrease in the sinusoidal motion, as well as an infirmity of transgenic worms when compared to control worms. These results support the hypothesis that aluminum may play a role in neurodegeneration in C. elegans, and may influence and increase the progression of Alzheimer's disease. This work was supported by National Science Foundation grants DUE-1058829, DMR-0923047 DUE-0806660 and Lock Haven FPDC grants.

  5. Status of international benchmark experiment for effective delayed neutron fraction ({beta}eff)

    Energy Technology Data Exchange (ETDEWEB)

    Okajima, S.; Sakurai, T.; Mukaiyama, T. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    To improve the prediction accuracy of the {beta}eff, the program of the international benchmark experiment (Beta Effect Reactor Experiment for a New International Collaborative Evaluation: BERNICE) was planned. This program composed of two parts; BERNICE-MASURCA and BERNICE-FCA. The former one was carried out in the fast critical facility MASURCA of CEA, FRANCE between 1993 and 1994. The latter one started in the FCA, JAERI in 1995 and still is going. In these benchmark experiments, various experimental techniques have been applied for in-pile measurements of the {beta}eff. The accuracy of the measurements was better than 3%. (author)

  6. Oral Ascorbic Acid in Combination with Beta-Blockers Is More Effective than Beta-Blockers Alone in the Prevention of Atrial Fibrillation after Coronary Artery Bypass Grafting

    OpenAIRE

    Eslami, Masoud; Badkoubeh, Roya Sattarzadeh; Mousavi, Mehdi; Radmehr, Hassan; Salehi, Mehrdad; Tavakoli, Nafiseh; Avadi, Mohamad Reza

    2007-01-01

    Because adrenergic beta antagonists are not sufficient to prevent atrial fibrillation after coronary artery bypass grafting, this prospective, randomized trial was designed to evaluate the effects of ascorbic acid as an adjunct to β-blockers.

  7. The long term effects of {sup 137}Cs {gamma}-rays and tritiated water on induction on teratogenesis in rats

    Energy Technology Data Exchange (ETDEWEB)

    Shoji, Shuneki [Hiroshima Univ., Research Institute for Radiation Biology and Medicine, Hiroshima (Japan)

    2003-07-01

    The purpose of the present study is to evaluate the teratogenesis caused by {sup 137}Cs {gamma}-rays radiation and tritiated water (tritium {beta}-rays, HTO) in rats under long-term exposures. Many congenital anomalies are caused by environmental factors, and it is likely that this assessment of teratogenesis will be very important in the future. Pregnant Donryu strain rats were irradiated with {sup 137}Cs {gamma}-rays on days 9-18 of gestation. The animals were sacrificed on day 18 of gestation and the contents of each uterine horn were examined. The numbers of surviving, dead and resorbed fetuses were recorded. The surviving fetuses were examined for external and visceral malformations. Also given here is a measure of the relative biological effectiveness (RBE) of tritiated water (HTO) compared to that for {sup 137}Cs {gamma}-rays regarding the induction of developmental anomalies such as neurocristopathy in pregnant Donryu rats. Radiation exposures were approximately 0, 1, 2, 3, 4, 5 and 6 Gy for both tritiated water and {sup 137}Cs {gamma}-rays. Teratogenesis was dose dependent for both radiation groups. Our studies show that {sup 137}Cs {gamma}-rays and HTO irradiation induce similar malformations of the cardiovascular, respiratory and skeletal systems in rat fetuses. However, a number of fetuses exhibiting growth retardation, general edema, persistent atrioventricular canal, eye defects, microcephaly and craniofacial defects following maternal exposure to HTO. These include hypoplasia of the pulmonary trunk (tetralogy of Fallot), DORV, ventricular septal defect, right aortic arch, coarctation of the aorta, aberrant right subclavian artery, hypoplasia of the thymus, craniofacial anomalies, hypoplasia or incomplete lungs and trachea, as well as limb and tail malformations in HTO syndrome. These results are similar to those found in human DiGeorge syndrome, which are considered pharyngeal arch syndromes related to a cephalic neutrocristopathy. A best estimation

  8. Biological Effects of Yeast β-Glucans

    Directory of Open Access Journals (Sweden)

    Vlatka Petravić-tominac

    2010-12-01

    Full Text Available β-Glucans are glucose polymers that naturally occur in yeasts, molds, algae, mushrooms, bacteria, oats and barley. Immunostimulation is one of the most important properties of β-glucans. They are classified as biological response modifiers and because of their biological activities they can be used in human and veterinary medicine and pharmacy. Additionally, β-glucans show interesting physicochemical properties and therefore could be applied in food and feed production as well as in cosmetic and chemical industries. Immunomodulation by β-glucan, both in vitro and in vivo, inhibits cancer cell growth and metastasis and prevents or reduces bacterial infection. In humans, dietary β-glucan lowers blood cholesterol, improves glucose utilization by body cells and also helps wound healing. β-Glucans work, in part, by stimulating the innate immune mechanism to fight a range of foreign challenges and could be used as an adjuvant, in combination with anti infective or antineoplastic agents, radiotherapy, and a range of topical agents and nutrients. The structure of β-glucans depends on the source they are isolated from. Native β-glucan molecules can be linked and branched in several ways. Biological properties of different β-glucan molecules are dependent on their molecular structure. Some authors claim that the β-(1→3, (1→6-glucan derived from yeast Saccharomyces cerevisiae produce the highest biological effects. Thus, in this review the β-glucans and their metabolic activity are discussed, with the special accent on those isolated from yeast. Other possible β-glucan applications, directed to cosmetic production, non-medical application in pharmaceutical and chemical industry, are also discussed.

  9. Effects of Pesticides on Biological Systems

    Directory of Open Access Journals (Sweden)

    Ergul Belge Kurutas

    2003-06-01

    Full Text Available The use of pesticid both in Turkey and other contries is widespread in order to combat against many pests which cause economical damages. However, pesticides in human pass through skin, respiratory or digestive systems and is metabolized by monooxygenase system dependent upon cytocrome P450 in liver. They also give rise to severe decreases cytochrome P450 and amount of "hem" enzyme activites of glucose-6-phosphatase, pyrophosphatase by stimulating lipid peroxidation on hepatic microsomes. In this study effects of pesticides on biological systems will be presented in genaral terms. [Archives Medical Review Journal 2003; 12(3.000: 215-228

  10. Biological effects data: Fluoride and sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    McMechan, K.J. (ed.); Holton, R.L.; Ulbricht, R.J.; Morgan , J.B.

    1975-04-01

    The Alumax Pacific Aluminum Corporation has proposed construction of an aluminum reduction facility near Youngs Bay at Warrenton, Oregon. This report comprises one part of the final report to Alumax on a research project entitled, Physical, Chemical and Biological Studies of Youngs Bay.'' It presents data pertaining to the potential biological effects of fluoride and sulfur dioxide, two potentially hazardous plant-stack emissions, on selected aquatic species of the area. Companion volumes provide a description of the physical characteristics the geochemistry, and the aquatic animals present in Youngs Bay and adjacent ecosystems. An introductory volume provides general information and maps of the area, and summarizes the conclusions of all four studies. The data from the two phases of the experimental program are included in this report: lethal studies on the effects of selected levels of fluoride and sulfur dioxide on the survival rate of eleven Youngs Bay faunal species from four phyla, and sublethal studies on the effects of fluoride and sulfur dioxide on the rate of primary production of phytoplankton. 44 refs., 18 figs., 38 tabs.

  11. Structure of the beta 2 homodimer of bacterial luciferase from Vibrio harveyi: X-ray analysis of a kinetic protein folding trap.

    Science.gov (United States)

    Thoden, J. B.; Holden, H. M.; Fisher, A. J.; Sinclair, J. F.; Wesenberg, G.; Baldwin, T. O.; Rayment, I.

    1997-01-01

    Luciferase, as isolated from Vibrio harveyi, is an alpha beta heterodimer. When allowed to fold in the absence of the alpha subunit, either in vitro or in vivo, the beta subunit of enzyme will form a kinetically stable homodimer that does not unfold even after prolonged incubation in 5 M urea at pH 7.0 and 18 degrees C. This form of the beta subunit, arising via kinetic partitioning on the folding pathway, appears to constitute a kinetically trapped alternative to the heterodimeric enzyme (Sinclair JF, Ziegler MM, Baldwin TO. 1994. Kinetic partitioning during protein folding yields multiple native states. Nature Struct Biol 1: 320-326). Here we describe the X-ray crystal structure of the beta 2 homodimer of luciferase from V. harveyi determined and refined at 1.95 A resolution. Crystals employed in the investigational belonged to the orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions of a = 58.8 A, b = 62.0 A, and c = 218.2 A and contained one dimer per asymmetric unit. Like that observed in the functional luciferase alpha beta heterodimer, the major tertiary structural motif of each beta subunit consists of an (alpha/beta)8 barrel (Fisher AJ, Raushel FM, Baldwin TO, Rayment I. 1995. Three-dimensional structure of bacterial luciferase from Vibrio harveyi at 2.4 A resolution. Biochemistry 34: 6581-6586). The root-mean-square deviation of the alpha-carbon coordinates between the beta subunits of the hetero- and homodimers is 0.7 A. This high resolution X-ray analysis demonstrated that "domain" or "loop" swapping has not occurred upon formation of the beta 2 homodimer and thus the stability of the beta 2 species to denaturation cannot be explained in such simple terms. In fact, the subunit:subunit interfaces observed in both the beta 2 homodimer and alpha beta heterodimer are remarkably similar in hydrogen-bonding patterns and buried surface areas. PMID:9007973

  12. Application of X-ray fluorescence analytical techniques in phytoremediation and plant biology studies

    Energy Technology Data Exchange (ETDEWEB)

    Necemer, Marijan [Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)], E-mail: marijan.necemer@ijs.si; Kump, Peter; Scancar, Janez; Jacimovic, Radojko; Simcic, Jurij; Pelicon, Primoz; Budnar, Milos; Jeran, Zvonka [Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Pongrac, Paula; Regvar, Marjana; Vogel-Mikus, Katarina [Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia)

    2008-11-15

    Phytoremediation is an emerging technology that employs the use of higher plants for the clean-up of contaminated environments. Progress in the field is however handicapped by limited knowledge of the biological processes involved in plant metal uptake, translocation, tolerance and plant-microbe-soil interactions; therefore a better understanding of the basic biological mechanisms involved in plant/microbe/soil/contaminant interactions would allow further optimization of phytoremediation technologies. In view of the needs of global environmental protection, it is important that in phytoremediation and plant biology studies the analytical procedures for elemental determination in plant tissues and soil should be fast and cheap, with simple sample preparation, and of adequate accuracy and reproducibility. The aim of this study was therefore to present the main characteristics, sample preparation protocols and applications of X-ray fluorescence-based analytical techniques (energy dispersive X-ray fluorescence spectrometry-EDXRF, total reflection X-ray fluorescence spectrometry-TXRF and micro-proton induced X-ray emission-micro-PIXE). Element concentrations in plant leaves from metal polluted and non-polluted sites, as well as standard reference materials, were analyzed by the mentioned techniques, and additionally by instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). The results were compared and critically evaluated in order to assess the performance and capability of X-ray fluorescence-based techniques in phytoremediation and plant biology studies. It is the EDXRF, which is recommended as suitable to be used in the analyses of a large number of samples, because it is multi-elemental, requires only simple preparation of sample material, and it is analytically comparable to the most frequently used instrumental chemical techniques. The TXRF is compatible to FAAS in sample preparation, but relative to AAS it is fast, sensitive and

  13. Application of X-ray fluorescence analytical techniques in phytoremediation and plant biology studies

    International Nuclear Information System (INIS)

    Phytoremediation is an emerging technology that employs the use of higher plants for the clean-up of contaminated environments. Progress in the field is however handicapped by limited knowledge of the biological processes involved in plant metal uptake, translocation, tolerance and plant-microbe-soil interactions; therefore a better understanding of the basic biological mechanisms involved in plant/microbe/soil/contaminant interactions would allow further optimization of phytoremediation technologies. In view of the needs of global environmental protection, it is important that in phytoremediation and plant biology studies the analytical procedures for elemental determination in plant tissues and soil should be fast and cheap, with simple sample preparation, and of adequate accuracy and reproducibility. The aim of this study was therefore to present the main characteristics, sample preparation protocols and applications of X-ray fluorescence-based analytical techniques (energy dispersive X-ray fluorescence spectrometry-EDXRF, total reflection X-ray fluorescence spectrometry-TXRF and micro-proton induced X-ray emission-micro-PIXE). Element concentrations in plant leaves from metal polluted and non-polluted sites, as well as standard reference materials, were analyzed by the mentioned techniques, and additionally by instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). The results were compared and critically evaluated in order to assess the performance and capability of X-ray fluorescence-based techniques in phytoremediation and plant biology studies. It is the EDXRF, which is recommended as suitable to be used in the analyses of a large number of samples, because it is multi-elemental, requires only simple preparation of sample material, and it is analytically comparable to the most frequently used instrumental chemical techniques. The TXRF is compatible to FAAS in sample preparation, but relative to AAS it is fast, sensitive and

  14. Application of X-ray fluorescence analytical techniques in phytoremediation and plant biology studies

    Science.gov (United States)

    Nečemer, Marijan; Kump, Peter; Ščančar, Janez; Jaćimović, Radojko; Simčič, Jurij; Pelicon, Primož; Budnar, Miloš; Jeran, Zvonka; Pongrac, Paula; Regvar, Marjana; Vogel-Mikuš, Katarina

    2008-11-01

    Phytoremediation is an emerging technology that employs the use of higher plants for the clean-up of contaminated environments. Progress in the field is however handicapped by limited knowledge of the biological processes involved in plant metal uptake, translocation, tolerance and plant-microbe-soil interactions; therefore a better understanding of the basic biological mechanisms involved in plant/microbe/soil/contaminant interactions would allow further optimization of phytoremediation technologies. In view of the needs of global environmental protection, it is important that in phytoremediation and plant biology studies the analytical procedures for elemental determination in plant tissues and soil should be fast and cheap, with simple sample preparation, and of adequate accuracy and reproducibility. The aim of this study was therefore to present the main characteristics, sample preparation protocols and applications of X-ray fluorescence-based analytical techniques (energy dispersive X-ray fluorescence spectrometry—EDXRF, total reflection X-ray fluorescence spectrometry—TXRF and micro-proton induced X-ray emission—micro-PIXE). Element concentrations in plant leaves from metal polluted and non-polluted sites, as well as standard reference materials, were analyzed by the mentioned techniques, and additionally by instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). The results were compared and critically evaluated in order to assess the performance and capability of X-ray fluorescence-based techniques in phytoremediation and plant biology studies. It is the EDXRF, which is recommended as suitable to be used in the analyses of a large number of samples, because it is multi-elemental, requires only simple preparation of sample material, and it is analytically comparable to the most frequently used instrumental chemical techniques. The TXRF is compatible to FAAS in sample preparation, but relative to AAS it is fast

  15. Effect of beta-D-xyloside on the glomerular proteoglycans. I. Biochemical studies

    OpenAIRE

    1984-01-01

    The effect of p-nitrophenyl-beta-D-xylopyranoside on glomerular extracellular matrices (glomerular basement membrane and mesangial matrix) proteoglycans was studied. The proteoglycans of rat kidneys were labeled with [35S]sulfate in the presence or absence of beta- xyloside (2.5 mM) by using an isolated organ perfusion system. The proteoglycans from the glomeruli and perfusion medium were isolated and characterized by Sepharose CL-6B chromatography and by their behavior in CsCl density gradie...

  16. Molecular effects in the neutrino mass determination from beta-decay of the tritium molecule

    International Nuclear Information System (INIS)

    Molecular final state energies and transition probabilities have been computed for beta-decay of the tritium molecule. The results are of sufficient accuracy to make a determination of the electron neutrino rest mass with an error not exceeding a few tenths of an electron volt. Effects of approximate models of tritium beta-decay on the neutrino mass determination are discussed. 14 refs., 3 figs., 1 tab

  17. Effect of sterilization on the properties of CDHA-OCP-beta-TCP biomaterial

    OpenAIRE

    Loreley Morejón-Alonso; Raúl García Carrodeguas; José Ángel Delgado García-Menocal; José Antonio Alonso Pérez; Salvador Martínez Manent

    2007-01-01

    The effect of the method of sterilization on the physical, chemical and mechanical properties of a new bone repairing material was studied. The material was obtained by thermal hydrolysis of beta-tricalcium phosphate/orthophosphoric acid cement and was composed of calcium deficient hydroxyapatite, octacalcium phosphate (OCP), and beta-tricalcium phosphate. Partial decomposition of the OCP was observed after sterilization for the three methods. Decomposition increased to the following sequence...

  18. Influence of beta adrenergic blockade on effects of physical training in patients with ischaemic heart disease.

    OpenAIRE

    L. Vanhees; Fagard, R.; Amery, A

    1982-01-01

    Reduction in heart rate during submaximal exercise is often used to judge the progress of patients with ischaemic heart disease in the course of a physical training programme. Some patients, however, are treated with beta adrenergic blocking drugs and it remains controversial if chronic beta blockade influences the effects of training and if heart rate remains a useful guide in the evaluation of the state of training of these patients. Male postinfarction patients, 15 treated with and 15 with...

  19. MEAT SCIENCE AND MUSCLE BIOLOGY SYMPOSIUM--implant and beta agonist impacts on beef palatability.

    Science.gov (United States)

    Garmyn, A J; Miller, M F

    2014-01-01

    The use of anabolic implants has a long-standing place in the cattle feeding industry, due to their positive impact on growth performance and subsequent profitability. However, implants can have adverse effects on carcass quality, shear force, and eating quality depending on the dose and frequency, or what some refer to as the aggressiveness of the implant regimen administered. Within the past decade, a new class of growth promotants, known as β-adrenergic agonists (βAA), has emerged in the beef feeding industry in the United States. Currently, 2 have gained U.S. Food and Drug Administration approval for use in beef finishing diets to improve performance and carcass yields. Much like anabolic implants, these repartitioning agents can have negative effects on Warner-Bratzler shear force (WBSF), but the differences do not necessarily translate directly to consumer responses for palatability and acceptance in some instances, especially when tenderness is managed through proper postmortem aging. As researchers continued to investigate the mechanisms responsible for the impact of βAA, inevitably this led to consideration of the interaction between βAA and anabolic implants. Early work combining zilpaterol hydrochloride (ZH) with anabolic implants improved performance, carcass yield, and meat yield with additive negative effects on WBSF. Similar results were produced when pairing ZH with anabolic steroids equipped with various release patterns. As with any tool, the key to success is proper management. Certain cattle populations may be better suited to receive growth promotants such as implants and βAA, and postmortem management of subprimal cuts becomes vital when producers take more aggressive approaches to improve performance and yield. The objective of this review is to overview research findings related to the impact of growth promotant technologies on beef palatability, focusing specifically on the role of implants and βAA on carcass quality, beef tenderness

  20. Influence from low energy x-rays and Auger electrons on 4. pi beta. -. gamma. coincidence measurements of electron-capture-decaying nuclides

    Energy Technology Data Exchange (ETDEWEB)

    Funck, E.; Larsen, A.N. (Physikalisch-Technische Bundesanstalt, Braunschweig (Germany, F.R.). Abt. Atomphysik; Commission of the European Communities, Geel (Belgium). Central Bureau for Nuclear Measurements)

    1983-03-01

    The influence of low energy x-rays and Auger electrons emitted by electron capture nuclides on 4..pi beta..-..gamma.. coincidence measurements is investigated. Under the assumption that these radiations are not detected, correction terms are developed for a number of nuclides that are in common use.

  1. Ionizing radiation effects on biological macromolecules

    International Nuclear Information System (INIS)

    Ionizing radiation is one of the main environmental factors for life, particularly for human beings. The primary effects of ionizing radiation produce the perturbation of biomacromolecules functionality (DNA and proteins). This effect occurs by direct action and by the indirect way of water molecules radiolysis. These primary effects result in a cascade of biochemical and biological consequences that may finally influence the general functions of the organism. In the last five decades the research activity in this field was focused on the detailed description of the effects on DNA molecules and their biochemical and biological consequences. The reason for this is the importance of the integrity of DNA for the cell life evolution, especially for the cell recovery processes or for the programmed cell death after irradiation. These aspects have main applications in very important fields as radioprotection and radiotherapy. In the present paper the mechanisms of ionizing radiation action at the molecular level will be reviewed, with focus on the protein level effects. Although comparatively a lower number of results was reported concerning the effects of ionizing radiation on the proteins, during the last years this field was reconsidered in the context of a new research trend in the field of genomics and proteomics. The structural changes which occur most often in the proteins are the breaks of chemical links, the chemical moieties ionization (for instance, the oxidation of the proteins) and the inter - protein new links (cross-linking). These changes result in a gradual loss of protein functionality, influencing particularly the ionic transport, the signal transduction across the membrane or intermolecular recognition processes of antibody-antigen type. Some studies on the ion artificial channels (as gramicidin and amphotericin) incorporated in model membranes (BLM-s or liposomes) describe structural and functional changes of the peptides after the exposure to

  2. Effects of Gamma Ray Bursts in Earth Biosphere

    CERN Document Server

    Martin, Osmel; Guimaraes, Mayrene; Penate, Liuba; Horvath, Jorge; Galante, Douglas

    2009-01-01

    We continue former work on the modeling of potential effects of Gamma Ray Bursts on Phanerozoic Earth. We focus on global biospheric effects of ozone depletion and show a first modeling of the spectral reduction of light by NO2 formed in the stratosphere. We also illustrate the current complexities involved in the prediction of how terrestrial ecosystems would respond to this kind of burst. We conclude that more biological field and laboratory data are needed to reach even moderate accuracy in this modeling

  3. Purification and biochemical characterization of the complete structure of a proteolytically modified beta-2-microglobulin with biological activity

    DEFF Research Database (Denmark)

    Nissen, Mogens Holst; Thim, L; Christensen, M

    1987-01-01

    . (1985) Clin. Chem. 31, 1411-1412; Nissen et al. (1984) Clin. Chim. Acta 141, 41-50]. In the present study we describe the purification and characterization of this modified human serum beta-2-m from patients with small-cell lung cancer. Purified urinary beta-2-m was added to the serum samples incubated...... analyzed by sodium dodecyl sulphate/polyacrylamide gel electrophoresis and analytical isoelectric focusing respectively. Amino acid analysis of m-beta-2-m revealed that the protein is missing one lysine residue compared to the composition deduced from the cDNA sequence of beta-2-m. Amino acid sequence...

  4. Correlated imaging of living biological cells with a soft X-ray microscope and a fluorescence microscope

    International Nuclear Information System (INIS)

    Soft X-ray microscope is a very powerful tool to observe cellular organelles of living biological. However the inner structures are very complicated and it is difficult to identify the organelles obtained with the soft X-ray microscopes. We have proposed a correlated imaging with a soft X-ray microscope and a fluorescence microscope that is to observe the same biological cells with the both microscopes at the same time. (author)

  5. Pancreatic Beta Cell G-Protein Coupled Receptors and Second Messenger Interactions: A Systems Biology Computational Analysis

    Science.gov (United States)

    Fridlyand, Leonid E.; Philipson, Louis H.

    2016-01-01

    Insulin secretory in pancreatic beta-cells responses to nutrient stimuli and hormonal modulators include multiple messengers and signaling pathways with complex interdependencies. Here we present a computational model that incorporates recent data on glucose metabolism, plasma membrane potential, G-protein-coupled-receptors (GPCR), cytoplasmic and endoplasmic reticulum calcium dynamics, cAMP and phospholipase C pathways that regulate interactions between second messengers in pancreatic beta-cells. The values of key model parameters were inferred from published experimental data. The model gives a reasonable fit to important aspects of experimentally measured metabolic and second messenger concentrations and provides a framework for analyzing the role of metabolic, hormones and neurotransmitters changes on insulin secretion. Our analysis of the dynamic data provides support for the hypothesis that activation of Ca2+-dependent adenylyl cyclases play a critical role in modulating the effects of glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and catecholamines. The regulatory properties of adenylyl cyclase isoforms determine fluctuations in cytoplasmic cAMP concentration and reveal a synergistic action of glucose, GLP-1 and GIP on insulin secretion. On the other hand, the regulatory properties of phospholipase C isoforms determine the interaction of glucose, acetylcholine and free fatty acids (FFA) (that act through the FFA receptors) on insulin secretion. We found that a combination of GPCR agonists activating different messenger pathways can stimulate insulin secretion more effectively than a combination of GPCR agonists for a single pathway. This analysis also suggests that the activators of GLP-1, GIP and FFA receptors may have a relatively low risk of hypoglycemia in fasting conditions whereas an activator of muscarinic receptors can increase this risk. This computational analysis demonstrates that study of second messenger

  6. Ferromagnetic and resistive wall effects on beta limit in a tokamak

    International Nuclear Information System (INIS)

    Ferromagnetic and resistive wall effect on beta limit in a tokamak is investigated. It is shown that the beta limit is reduced to 90% of that without ferromagnetic effect for high aspect ratio tokamak, if the ferromagnetic wall of relative permeability of 2 is used. The effect of toroidal plasma flow is also investigated, and the flow velocity of 0.03vta, vta is toroidal Alfven velocity, is sufficient for the resistive wall to have stability effect of ideal wall. Both the resistive wall and ideal kink modes are destabilized by the ferromagnetic wall effects. (author)

  7. Effects of halothane on the human beta-adrenergic receptor of lymphocyte membranes

    International Nuclear Information System (INIS)

    The effects of halothane on beta-adrenergic receptor antagonist interaction were studied using the membranes of human lymphocytes as a model. Membrane preparations of lymphocytes were obtained from blood samples withdrawn from seven healthy young volunteers. Beta-receptor studies were performed using (-)125I iodocyanopindolol (125ICP) binding. Non-specific binding was determined in the presence of (-)isoproterenol. Beta-receptor density (Bmax) and the dissociation constant (KD) for 125ICP were determined from saturation curves. Beta-receptor affinity for agonists evaluated by the IC50 (the concentration of isoproterenol required to inhibit 50% of specific 125ICP binding) and the dissociation constant (KL) for isoproterenol was established from competition curves. The effect of halothane 1%, in an air oxygen mixture (oxygen fraction: 0.3) administered by tonometry during ligand membrane incubation, on beta-adrenergic receptor, was compared to that of control experiments not exposed to halothane. Halothane produced a moderate but significant decrease of Bmax (-10%) and a significant increase in non-specific binding (+30%), while KD, IC50, and KL were unchanged. The authors conclude that halothane, in vitro, decreases beta-adrenergic receptor density. This effect could be mediated by an alteration of the receptor in the membrane due to action of halothane on the lipid phase of the membrane

  8. The antifibrotic effects of TGF-{beta}1 siRNA on hepatic fibrosis in rats

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Qing; Liu, Qi [Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Instituted for Virus Hepatitis and Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing (China); Xu, Ning [The Second Hospital of YuLin, Shanxi Province (China); Qian, Ke-Li; Qi, Jing-Hu; Sun, Yin-Chun; Xiao, Lang [Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Instituted for Virus Hepatitis and Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing (China); Shi, Xiao-Feng, E-mail: sxff2003@yahoo.com.cn [Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Instituted for Virus Hepatitis and Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing (China)

    2011-06-10

    Highlights: {yields} We constructed CCL4 induced liver fibrosis model successfully. {yields} We proofed that the TGF-{beta}1 siRNA had a definite therapy effect to CCL4 induced liver fibrosis. {yields} The therapy effect of TGF-{beta}1 siRNA had dose-dependent. -- Abstract: Background/aims: Hepatic fibrosis results from the excessive secretion of matrix proteins by hepatic stellate cells (HSCs), which proliferate during fibrotic liver injury. Transforming growth factor (TGF)-{beta}1 is the dominant stimulus for extracellular matrix (ECM) production by stellate cells. Our study was designed to investigate the antifibrotic effects of using short interference RNA (siRNA) to target TGF-{beta}1 in hepatic fibrosis and its mechanism in rats exposed to a high-fat diet and carbon tetrachloride (CCL4). Methods: A total of 40 healthy, male SD (Sprague-Dawley) rats were randomly divided into five even groups containing of eight rats each: normal group, model group, TGF-{beta}1 siRNA 0.125 mg/kg treatment group, TGF-{beta}1 siRNA 0.25 mg/kg treatment group and TGF-{beta}1 siRNA negative control group (0.25 mg/kg). CCL4 and a high-fat diet were used for 8 weeks to induce hepatic fibrosis. All the rats were then sacrificed to collect liver tissue samples. A portion of the liver samples were soaked in formalin for Hematoxylin-Eosin staining, classifying the degree of liver fibrosis, and detecting the expression of type I and III collagen and TGF-{beta}1; the remaining liver samples were stored in liquid nitrogen to be used for detecting TGF-{beta}1 by Western blotting and for measuring the mRNA expression of type I and III collagen and TGF-{beta}1 by quantitative real-time polymerase chain reaction. Results: Comparing the TGF-{beta}1 siRNA 0.25 mg/kg treatment group to the model group, the TGF-{beta}1 siRNA negative control group and the TGF-{beta}1 siRNA 0.125 mg/kg treatment group showed significantly reduced levels of pathological changes, protein expression and the m

  9. Binding capacity of a barley beta-D-glucan to the beta-glucan recognition molecule dectin-1.

    Science.gov (United States)

    Tada, Rui; Adachi, Yoshiyuki; Ishibashi, Ken-ichi; Tsubaki, Kazufumi; Ohno, Naohito

    2008-02-27

    To clarify whether barley beta-glucans exhibit their biological effects via binding to dectin-1, a pivotal receptor for beta-1,3-glucan, the structure of barley beta-glucan E70-S (BBG-70) was unambiguously investigated by NMR spectroscopy and studied for its binding capacity and specificity to dectin-1 by ELISA. NMR spectroscopy confirmed that BBG-70 contains two different linkage glucans, namely, alpha-glucan and beta-glucan, which are not covalently attached to one another. Beta-glucan within BBG-70 is a linear mixed-linkage beta-glucan composed of 1,3- and 1,4-beta-D-glucopyranose residues but does not contain the continuous 1,3-linkage. Competitive ELISA revealed that highly purified barley beta-glucan E70-S (pBBG-70) inhibits the binding of soluble dectin-1 to sonifilan (SPG), a beta-1,3-glucan, although at a concentration higher than that of SPG and laminarin. It was found that barley beta-glucan can be recognized by dectin-1, implying that barley beta-glucan might, at least in part, exhibit its biological effects via the recognition by dectin-1 of the ligand sugar structure, which may be formed by 1,3-beta- and 1,4-beta-glucosyl linkage. PMID:18205312

  10. Report on some Biological Responses to High Electric Fields and Indirect Action of Ultraviolot Rays

    Directory of Open Access Journals (Sweden)

    Kamal Djanab

    1960-01-01

    Full Text Available The similarities of effects produced hy radiation, electric field, ultraviolet rays and ozone on the platelet and blood corpuscles suggest the presence of a common factor. It is assumed that the effects of radiation is due the hydroperoxyl radical and we know it is the same for ozone and ultraviolet rays. These effects are useful for detecting to Some extent the primary or direct and the secondary effects of radiation due to the oxydising radicals; and we also may substitute x or"( rays radiotherapy by ozone in such cases as lung cancer.

  11. Tomographic imaging of biological specimens with the cryo transmission X-ray microscope

    International Nuclear Information System (INIS)

    Using the photoelectric absorption contrast between water and protein at 2.4 nm wavelength, cryo X-ray microscopy has visualized protein structures down to 30 nm size in unstained, unsectioned biological specimens. Due to the large depth of focus of the Fresnel zone plate objectives, computed tomography based on a tilt series of X-ray microscopic images can be used to reconstruct the three-dimensional specimen structure. This method has been applied to the green alga Chlamydomonas reinhardtii, and to cell nuclei of male Drosophila melanogaster fruit fly cells

  12. The biological effects of ozone depletion.

    Science.gov (United States)

    Young, A R

    1997-05-01

    Thinning of the ozone layer is predicted to result in increased levels of ultraviolet (UV) B radiation at the earth's surface. This effect has been confirmed by measurements made in relatively unpolluted areas such as Antarctica, the southern part of South America and at mid-to-high latitudes in the northern hemisphere. It has been harder to show in populated northern latitudes because of a number of confounding factors, notably weather systems and low level ozone pollution. Although UVB forms only a small proportion of the UV spectrum it has potent biological effects so that a small increase in penetration of UVB to the earth's surface has profound effects on a wide range of life forms. Most attention has been paid to the effects of an increase in UVB on human health, particularly the effects on skin cancer, resistance to infectious diseases and cataract formation. However, the effects of increased levels of UVB on other parts of the ecosystem, particularly on the primary producers in aquatic and terrestrial food chains, may be of even. PMID:9519507

  13. Effects of chronic delta-9-THC treatment on cardiac beta-adrenoceptors in rats

    Energy Technology Data Exchange (ETDEWEB)

    Evans, E.B.; Seifen, E.; Kennedy, R.H.; Kafiluddi, R.; Paule, M.G.; Scallet, A.C.; Ali, S.F.; Slikker, W. Jr.

    1987-10-01

    This study was designed to determine if chronic treatment with delta-9-tetrahydrocannabinol (THC) alters cardiac beta-adrenoceptors in the rat. Following daily oral administration of 10 or 20 mg/kg THC or an equivalent volume of control solvent for 90 days, rats were sacrificed, and sarcolemmal membranes were prepared from ventricular myocardium. Beta-adrenoceptor density and binding affinity estimated with (-)(/sup 3/H)dihydroalprenolol; a beta-adrenergic antagonist, were not significantly affected by treatment with THC when compared to vehicle controls. These results suggest that the tolerance to cardiovascular effects of THC which develops during chronic exposure in the rat is not associated with alterations in cardiac beta-adrenoceptors as monitored by radiolabeled antagonist binding.

  14. Alpha and beta adrenergic effects on metabolism in contracting, perfused muscle

    DEFF Research Database (Denmark)

    Richter, Erik; Ruderman, N B; Galbo, H

    1982-01-01

    The role of alpha- and beta-adrenergic receptor stimulation for the effect of epinephrine on muscle glycogenolysis, glucose- and oxygen uptake and muscle performance was studied in the perfused rat hindquarter at rest and during electrical stimulation (60 contractions/min). Adrenergic stimulation...... was obtained by epinephrine in a physiological concentration (2.4 X 10(-8) M) and alpha- and beta-adrenergic blockade by 10(-5) M phentolamine and propranolol, respectively. Epinephrine enhanced net glycogenolysis during contractions most markedly in slow-twitch red fibers. In these fibers the effect...... stimulation of alpha-adrenergic receptors and had a positive inotropic effect during contractions which was abolished by alpha- as well as by beta-adrenergic blockade. The results indicate that epinephrine has profound effects on contracting muscle, and that these effects are elicited through different...

  15. Determining biological fine structure by differential absorption of soft x-rays

    International Nuclear Information System (INIS)

    The use of soft x-ray contact microscopy in examining histochemically treated human tissue embedded in plastic and exposed as unstained thin sections is demonstrated. When our preliminary data revealed that we could clearly image not only the histochemical reaction product, but the unstained biological fine structure of the surrounding tissues, we decided to test our hypothesis further and see if we could image unstained biological molecular aggregates as well. For this part of the investigation, we chose to examine hydrated proteoglycan aggregates. Proteoglycans are an essential component of the organic matrix of cartilage, and play a primary role in the retention and maintenance of extracellular water. To avoid any artifacts due to the introduction of exogeneous materials, and examine the proteoglycan aggregates in their hydrated, natural configuration, we made contact x-ray images of isolated proteoglycan aggregates in water

  16. Study of the irradiation effects on thorium phosphate diphosphate ({beta}-TPD): consequences on its chemical durability; Etude des effets d'irradiation sur le phosphate diphosphate de thorium ({beta}-PDT): consequences sur la durabilite chimique

    Energy Technology Data Exchange (ETDEWEB)

    Tamain, C

    2005-12-15

    Since Thorium Phosphate Diphosphate (beta-TPD) can be considered as a potential host matrix for long-term storage in underground repository, it is necessary to study the irradiation effects on the structure of this ceramics and the consequences on its chemical durability. Sintered samples of beta-TPD and of associated solid solutions of beta-TUPD were irradiated under ion beams and then altered in aqueous solutions. Depending on the electronic LET value, beta-TPD can be completely or partly amorphized. Furthermore, the ability of recrystallization of the amorphous material by thermal annealing was also demonstrated. Some leaching tests, realized on these irradiated samples, have shown a significant effect of the amorphous fraction on the normalized dissolution rate which was increased by a factor of 10 from the crystallized to the fully amorphized material. Correlatively, the amorphous fraction also modified the delay to reach the saturation conditions associated to the thermodynamic equilibria involved. On the other hand, it exhibited no influence neither on other kinetic parameters, such as activation energy of the dissolution process or partial order related to the proton concentration, nor on the nature of the neo-formed phase formed at the saturation of the leachate and identified as Thorium Phosphate Hydrogeno-Phosphate Hydrate (TPHPH). Beta-TUPD samples were also irradiated by gamma and alpha rays during leaching tests to study the effects of radiolysis in the leaching medium on the normalized leaching rate. It appeared that the radiolytic species occurring in the dissolution mechanism were unstable, disappearing quickly when stopping the irradiation. (author)

  17. Lithium-Drifted Germanium Detectors for High Resolution Beta- and Gamma-Ray Spectroscopy

    International Nuclear Information System (INIS)

    Two types of germanium detectors have been fabricated using the lithium-ion drift technique. The first type have active volumes in excess of 6 cm3 and are primarily intended for high-energy (> 1.0 MeV) y-ray spectroscopy. The second type are large area, low capacity, windowless detectors intended for very high-resolution 6-ray and low-energy y-ray spectroscopy. Both types are operated in a vacuum at liquid nitrogen temperature (77°K). The large-volume detectors have areas greater than 6 cm2 with depletion depths in excess of 1 cm. The experimental resolution (FWHM) obtainable with these detectors is limited at low energies by the noise level of the pre-amplifier, while at high energies (>1MeV) the 1 imitation is due to amplifier instability. Typical resolutions are 3,6, and 12 keV for 0,122, 1,333and 5.0 MeV γ-rays respectively, while the photopeak efficiency ranges from approximately 75% at 122 keV to 1% at 1.333 MeV and 0. % at 5 MeV. At 5 MeV the pair-peak efficiency is ∼5%. Typical low-capacity detectors are slices (less than 5 mm thick) from the large volume detectors and have an area of 3 x 1 cm (the depletion depth). This gives a reduction in detector capacitance which results in a significant improvement in the resolution compared to that obtained with the large-volume detectors for a given pre-amplifier. At 0.122 and 1.333 MeV, resolutions of 1.9 keV and 4.1 keV respectively have been observed. Since these are essentially windowless detectors they make excellent small β-ray spectrometers. Typical resolution for the 625-keV K conversion electrons of 137Cs is less than 6 keV. These detectors are finding an increasingly wider application in both nuclear decay scheme work and in identifying the isotopic content of samples containing many isotopes. A more detailed evaluation of the properties and various applications of these two types of germanium detectors is described. (author)

  18. Dosimetry of beta-ray ophthalmic applicators: Comparison of different measurement methods

    International Nuclear Information System (INIS)

    An international intercomparison of the dosimetry of three beta particle emitting ophthalmic applicators was performed, which involved measurements with radiochromic film, thermoluminescence dosimeters (TLDs), alanine pellets, plastic scintillators, extrapolation ionization chambers, a small fixed-volume ionization chambers, a diode detector and a diamond detector. The sources studied were planar applicators of 90Sr-90Y and 106Ru-106Rh, and a concave applicator of 106Ru-106Rh. Comparisons were made of absolute dosimetry determined at 1 mm from the source surface in water or water-equivalent plastic, and relative dosimetry along and perpendicular to the source axes. The results of the intercomparison indicate that the various methods yield consistent absolute dosimetry results at the level of 10%-14% (one standard deviation) depending on the source. For relative dosimetry along the source axis at depths of 5 mm or less, the agreement was 3%-9% (one standard deviation) depending on the source and the depth. Crucial to the proper interpretation of the measurement results is an accurate knowledge of the detector geometry, i.e., sensitive volume and amount of insensitive covering material. From the results of these measurements, functions which describe the relative dose rate along and perpendicular to the source axes are suggested

  19. The effect of polymorphisms of beta2 adrenoceptors on response to long-acting beta2 agonists in Iranian asthmatic patients.

    OpenAIRE

    Fatemeh Soleimani; Fanak Fahimi; Parisa Adimi Naghan; Seyed Alireza Nadji; Saeid Morowati; Nima Naderi; Mohammad Reza Masjedi

    2013-01-01

    The results of many studies suggested possible relationship between polymorphism at codons 16 and 27 and development of tolerance to beta-2 adrenoceptor agonist responses as well as disease severity in asthmatic patients. This study was designed to evaluate the effect of polymorphism of beta2 adrenoceptors on response to salmeterol and fluticasone (as inhaled Seretide).Sixty-four patients with either mild or moderate-severe asthma were evaluated in this study. A four-week therapy with Seretid...

  20. Biological Effects of Yeast β-Glucans

    Directory of Open Access Journals (Sweden)

    Vlatka Petravić-Tominac

    2014-02-01

    Full Text Available Normal 0 21 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0pt 5.4pt 0pt 5.4pt; mso-para-margin:0pt; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} β-Glucans are glucose polymers that naturally occur in yeasts, molds, algae, mushrooms, bacteria, oats and barley. Immunostimulation is one of the most important properties of β-glucans. They are classified as biological response modifiers and because of their biological activities they can be used in human and veterinary medicine and pharmacy. Additionally, β-glucans show interesting physicochemical properties and therefore could be applied in food and feed production as well as in cosmetic and chemical industries. Immunomodulation by β-glucan, both in vitro and in vivo, inhibits cancer cell growth and metastasis and prevents or reduces bacterial infection. In humans, dietary β-glucan lowers blood cholesterol, improves glucose utilization by body cells and also helps wound healing. β-Glucans work, in part, by stimulating the innate immune mechanism to fight a range of foreign challenges and could be used as an adjuvant, in combination with anti infective or antineoplastic agents, radiotherapy, and a range of topical agents and nutrients. The structure of β-glucans depends on the source they are isolated from. Native β-glucan molecules can be linked and branched in several ways. Biological properties of different β-glucan molecules are dependent on their molecular structure. Some authors claim that the β-(1→3, (1→6-glucan derived from yeast Saccharomyces cerevisiae produce the highest biological effects. Thus, in this review the β-glucans and their metabolic

  1. The effect of smoking cessation pharmacotherapies on pancreatic beta cell function

    International Nuclear Information System (INIS)

    The goal of our study was to evaluate whether drugs currently used for smoking cessation (i.e., nicotine replacement therapy, varenicline [a partial agonist at nicotinic acetylcholine receptors (nAChR)] and bupropion [which acts in part as a nAChR antagonist]) can affect beta cell function and determine the mechanism(s) of this effect. INS-1E cells, a rat beta cell line, were treated with nicotine, varenicline and bupropion to determine their effects on beta cell function, mitochondrial electron transport chain enzyme activity and cellular/oxidative stress. Treatment of INS-1E cells with equimolar concentrations (1 μM) of three test compounds resulted in an ablation of normal glucose-stimulated insulin secretion by the cells. This disruption of normal beta cell function was associated with mitochondrial dysfunction since all three compounds tested significantly decreased the activity of mitochondrial electron transport chain enzyme activity. These results raise the possibility that the currently available smoking cessation pharmacotherapies may also have adverse effects on beta cell function and thus glycemic control in vivo. Therefore whether or not the use of nicotine replacement therapy, varenicline and bupropion can cause endocrine changes which are consistent with impaired pancreatic function warrants further investigation. -- Highlights: ► Smoking cessation drugs have the potential to disrupt beta cell function in vitro. ► The effects of nicotine, varenicline and bupropion are similar. ► The impaired beta cell function is mediated by mitochondrial dysfunction. ► If similar effects are seen in vivo, these drugs may increase the risk of diabetes.

  2. The effect of smoking cessation pharmacotherapies on pancreatic beta cell function

    Energy Technology Data Exchange (ETDEWEB)

    Woynillowicz, Amanda K. [Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON, Canada L8N 3Z5 (Canada); Raha, Sandeep [Department of Pediatrics, McMaster University, Hamilton, ON, Canada L8N 3Z5 (Canada); Nicholson, Catherine J. [Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON, Canada L8N 3Z5 (Canada); Holloway, Alison C., E-mail: hollow@mcmaster.ca [Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON, Canada L8N 3Z5 (Canada)

    2012-11-15

    The goal of our study was to evaluate whether drugs currently used for smoking cessation (i.e., nicotine replacement therapy, varenicline [a partial agonist at nicotinic acetylcholine receptors (nAChR)] and bupropion [which acts in part as a nAChR antagonist]) can affect beta cell function and determine the mechanism(s) of this effect. INS-1E cells, a rat beta cell line, were treated with nicotine, varenicline and bupropion to determine their effects on beta cell function, mitochondrial electron transport chain enzyme activity and cellular/oxidative stress. Treatment of INS-1E cells with equimolar concentrations (1 μM) of three test compounds resulted in an ablation of normal glucose-stimulated insulin secretion by the cells. This disruption of normal beta cell function was associated with mitochondrial dysfunction since all three compounds tested significantly decreased the activity of mitochondrial electron transport chain enzyme activity. These results raise the possibility that the currently available smoking cessation pharmacotherapies may also have adverse effects on beta cell function and thus glycemic control in vivo. Therefore whether or not the use of nicotine replacement therapy, varenicline and bupropion can cause endocrine changes which are consistent with impaired pancreatic function warrants further investigation. -- Highlights: ► Smoking cessation drugs have the potential to disrupt beta cell function in vitro. ► The effects of nicotine, varenicline and bupropion are similar. ► The impaired beta cell function is mediated by mitochondrial dysfunction. ► If similar effects are seen in vivo, these drugs may increase the risk of diabetes.

  3. Biological dosimetry by the radiation effects on the skin

    International Nuclear Information System (INIS)

    In cases of partial body over-exposure, the dose estimation with personal monitors or with reconstruction of exposed conditions is often impossible without considerable error. Clinical signs of irradiated skin, such as epilation or moist desquamation have been used as the indicators of doses in the radiological accidents, because each sign has the threshold dose. As hair growth is known to be sensitive to radiation, the dose-effect relationship of the delay of hair regrowth and the reduction in hair length of mice after irradiation were examined to investigate if they can be used as biological dosimeters. Hairs on the dorsal skin of 290 ICR mice (8 weeks old) were shaved and irradiated with a Sr-90/Y-90 β-ray source in the early anagen and the midanagen stages of the hair cycle. Skin doses were from 0.5 to 10 Gy. The time of hair regrowth and the hair length were examined with the scaling loupe. Dose-effect relationship of the delay of hair regrowth and reduction in hair length were both clearly dose dependent, fitting the L-Q or L function depending on the stage. Dose estimation functions were derived from the dose-effect relationship curves. The histological observations suggested that hair growth retardation caused by irradiation in midanagen might be due to the cell death and the depression of mitosis in the hair matrix cells. This dose estimation method was applied to the case who was over-exposed to X-ray on his hand and fingers. The findings showed that hair regrowth delay was a sensitive biological dosimeter in the case of partial body over-exposure, which could be applied as early as a few days after over-exposure. The method was simple and non-invasive to the exposed patient. (author)

  4. Effects of concomitant use of fibroblast growth factor (FGF)-2 with beta-tricalcium phosphate ({beta}-TCP) on the beagle dog 1-wall periodontal defect model

    Energy Technology Data Exchange (ETDEWEB)

    Anzai, Jun, E-mail: anzai_jun@kaken.co.jp [Pharmacology Department, Central Research Laboratories, Kaken Pharmaceutical Co., Ltd., 14, Shinomiya, Minamigawara-cho, Yamashina-ku, Kyoto 607-8042 (Japan); Department of Periodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 (Japan); Kitamura, Masahiro, E-mail: kitamura@dent.osaka-u.ac.jp [Department of Periodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nozaki, Takenori, E-mail: tnozaki@dent.osaka-u.ac.jp [Department of Periodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nagayasu, Toshie, E-mail: nagayasu_toshie@kaken.co.jp [Pharmacology Department, Central Research Laboratories, Kaken Pharmaceutical Co., Ltd., 14, Shinomiya, Minamigawara-cho, Yamashina-ku, Kyoto 607-8042 (Japan); Terashima, Akio, E-mail: terashima_akio@kaken.co.jp [Pharmacology Department, Central Research Laboratories, Kaken Pharmaceutical Co., Ltd., 14, Shinomiya, Minamigawara-cho, Yamashina-ku, Kyoto 607-8042 (Japan); Asano, Taiji, E-mail: asano_taiji@kaken.co.jp [Pharmacology Department, Central Research Laboratories, Kaken Pharmaceutical Co., Ltd., 14, Shinomiya, Minamigawara-cho, Yamashina-ku, Kyoto 607-8042 (Japan); Murakami, Shinya, E-mail: ipshinya@dent.osaka-u.ac.jp [Department of Periodontology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2010-12-17

    Research highlights: {yields} Concomitant use of FGF-2 and {beta}-TCP (an osteo-conductive scaffold) significantly promotes periodontal regeneration in the severe periodontitis model (1-wall defect model) of beagle dog. {yields} FGF-2 enhanced new bone formation via {beta}-TCP at the defects. {yields} In particular, FGF-2 dramatically regenerated new periodontal ligament and cementum formations at the defects, that is one of the most important healing outcomes during the process of periodontal regeneration. {yields} Epithelial downgrowth (undesirable wound healing) was decreased by administration of FGF-2. {yields} This manuscript indicates for the first time that concomitant use of FGF-2 and {beta}-TCP is efficacious in regenerating periodontal tissue following severe destruction of the tissue by progression of periodontitis. -- Abstract: The effects of concomitant use of fibroblast growth factor-2 (FGF-2) and beta-tricalcium phosphate ({beta}-TCP) on periodontal regeneration were investigated in the beagle dog 1-wall periodontal defect model. One-wall periodontal defects were created in the mesial portion of both sides of the mandibular first molars, and 0.3% FGF-2 plus {beta}-TCP or {beta}-TCP alone was administered. Radiographic evaluation was performed at 0, 3, and 6 weeks. At 6 weeks, the periodontium with the defect site was removed and histologically analyzed. Radiographic findings showed that co-administration of FGF-2 significantly increased bone mineral contents of the defect sites compared with {beta}-TCP alone. Histologic analysis revealed that the length of the regenerated periodontal ligament, the cementum, distance to the junctional epithelium, new bone height, and area of newly formed bone were significantly increased in the FGF-2 group. No abnormal inflammatory response or ankylosis was observed in either group. These findings indicate the efficacy of concomitant use of FGF-2 and {beta}-TCP as an osteoconductive material for periodontal

  5. Tomographic imaging of cryogenic biological specimens with the X-ray microscope at BESSY I

    International Nuclear Information System (INIS)

    Soft X-ray microscopy employs the natural absorption contrast between water and protein in the 2.34-4.38 nm wavelength region with a resolution down to 30 nm. The large depth of focus of the Fresnel zone plates used as X-ray objectives permits tomographic reconstruction based on the microscopic images. High-resolution images require a high specimen radiation dose, and a large number of images taken at different viewing angles is needed for tomographic reconstruction. Therefore, cryo microscopy is necessary to preserve the structural integrity of hydrated biological specimens during image acquisition. The cryo transmission X-ray microscope at the electron storage ring BESSY I (Berlin) was used to obtain a tilt series of images of the frozen-hydrated green alga Chlamydomonas reinhardtii. The living specimens were inserted into borosilicate capillaries, then rapidly cooled by plunging into liquid nitrogen. The capillary specimen holders allow image acquisition over the full angular range of 180 deg. . The reconstruction shows details inside the alga down to 60 nm size and conveys a detailed impression of the specimen structure. This technique is expected to be applicable to a wide range of biological specimens, such as the cell nucleus. It offers the possibility of imaging the three-dimensional structure of hydrated biological specimens close to their natural living state

  6. Biological effects of space radiation and development of effective countermeasures

    Science.gov (United States)

    Kennedy, Ann R.

    2014-04-01

    As part of a program to assess the adverse biological effects expected from astronauts' exposure to space radiation, numerous different biological effects relating to astronauts' health have been evaluated. There has been major focus recently on the assessment of risks related to exposure to solar particle event (SPE) radiation. The effects related to various types of space radiation exposure that have been evaluated are: gene expression changes (primarily associated with programmed cell death and extracellular matrix (ECM) remodeling), oxidative stress, gastrointestinal tract bacterial translocation and immune system activation, peripheral hematopoietic cell counts, emesis, blood coagulation, skin, behavior/fatigue (including social exploration, submaximal exercise treadmill and spontaneous locomotor activity), heart functions, alterations in biological endpoints related to astronauts' vision problems (lumbar puncture/intracranial pressure, ocular ultrasound and histopathology studies), and survival, as well as long-term effects such as cancer and cataract development. A number of different countermeasures have been identified that can potentially mitigate or prevent the adverse biological effects resulting from exposure to space radiation.

  7. Studies of the $\\beta$-decay of Kr and Sr nuclei on and near the N=Z line with a Total Absorption $\\gamma$-ray Spectrometer

    CERN Multimedia

    2002-01-01

    It is proposed to measure the Gamow-Teller strength distribution in the decays of $^{71-75}$Kr and $^{75,76}$Sr using a Total Absorption Gamma-ray Spectrometer (TAGS) based on a large NaI(TI) detector. The $\\gamma$-rays emitted in these decays will be detected in the TAGS in coincidence with positrons and X-rays from electron capture. Measurements of $\\beta$-delayed particles will also be performed in coincidence with the TAGS. Comparison with theoretical calculations based on the mean field approach, Tamm-Dancoff and QRPA method should allow a determination of the shapes of the ground states of these nuclei.

  8. Finite beta and compressibility effects on stability of resistive modes in toroidal geometry

    Energy Technology Data Exchange (ETDEWEB)

    Leboeuf, J.-N.G. [Oak Ridge National Lab., TN (United States); Kurita, Gen-ichi

    1998-03-01

    Linear resistive stability results obtained from the toroidal magnetohydrodynamic codes FAR developed at the Oak Ridge National Laboratory in United States of America and AEOLUS developed at the Japan Atomic Energy Research Institute are compared for carefully constructed benchmark profiles and parameters. These are unstable to a tearing mode with toroidal mode number n=1. The eigenvalues and eigenfunctions calculated with both codes are in close agreement and show that the effect of compressibility is weak for these modes. The effect of finite plasma beta is considered, and the eigenvalues calculated by the FAR and AEOLUS codes also show good agreement. It is shown that the finite beta has a stabilizing effect on the toroidal tearing mode, but that the compressibility also has little effect on finite beta tearing modes. (author)

  9. Microwave radiation: biological effects and exposure standards

    Energy Technology Data Exchange (ETDEWEB)

    Lindsay, I.R.

    1981-01-01

    The thermal effects of microwave radiation are well recognized and are discussed with particular reference to cataractogenesis; the possibility of an association cannot be questioned. Postulated nonthermal effects comprise an asthenic syndrome, and for the most part the disturbances lie within clinical norms and tolerances, and are reversible. World opinion on safe exposure levels for microwave radiation is varied, and this had led to national standards disparate by three to four orders of magnitude. The US and UK exposure standard of 10 mW/cm/sup 2/ was determined over two decades ago; the possibility of a change to a more restrictive level, in line with other countries, in the near future is examined. It is concluded that such a change, without scientific rationale, is not justified. Some biological implications of the microwave radiation from the solar power satellite are considered in terms of precautions to be taken by personnel working in the vicinity of the rectenna, effects on cardiac pacemakers, and any potential effects on birds. 14 references.

  10. Contrast media: Biologic effects and clinical application

    International Nuclear Information System (INIS)

    An overview is presented of the recent developments in contrast media and their clinical applications, plus the current state-of-the-art in computerized tomography, digital subtraction angiography, ultrasound and magnetic resonance imaging (MRI). Contents of these volumes include: an in-depth review of the historical development, modern perspectives in structure-function relationships, biologic effects on hemostats, gastrointestinal, cardiovascular systems and drug interactions. Critical and basic issues, including cellular toxicity, mutagenesis, synergism between radiation and contrast agents, mechanisms in contrast-induced reactions, and the management of such reactions in high-risk patients are also presented. Specific applications of paramagnetic compounds in MRI and the recent concept of liposome-encapsulated and particulate suspension of contrast materials in diagnostic imaging are thoroughly discussed

  11. Contrast media: Biologic effects and clinical application

    Energy Technology Data Exchange (ETDEWEB)

    Parvez, Z.; Moncada, R.; Sovak, M.

    1987-01-01

    An overview is presented of the recent developments in contrast media and their clinical applications, plus the current state-of-the-art in computerized tomography, digital subtraction angiography, ultrasound and magnetic resonance imaging (MRI). Contents of these volumes include: an in-depth review of the historical development, modern perspectives in structure-function relationships, biologic effects on hemostats, gastrointestinal, cardiovascular systems and drug interactions. Critical and basic issues, including cellular toxicity, mutagenesis, synergism between radiation and contrast agents, mechanisms in contrast-induced reactions, and the management of such reactions in high-risk patients are also presented. Specific applications of paramagnetic compounds in MRI and the recent concept of liposome-encapsulated and particulate suspension of contrast materials in diagnostic imaging are thoroughly discussed.

  12. Generalized X-ray and neutron crystallographic analysis: more accurate and complete structures for biological macromolecules

    International Nuclear Information System (INIS)

    X-ray and neutron crystallographic data have been combined in a joint structure-refinement procedure that has been developed using recent advances in modern computational methodologies, including cross-validated maximum-likelihood target functions with gradient-based optimization and simulated annealing. X-ray and neutron crystallographic techniques provide complementary information on the structure and function of biological macromolecules. X-ray and neutron (XN) crystallographic data have been combined in a joint structure-refinement procedure that has been developed using recent advances in modern computational methodologies, including cross-validated maximum-likelihood target functions with gradient-based optimization and simulated annealing. The XN approach for complete (including hydrogen) macromolecular structure analysis provides more accurate and complete structures, as demonstrated for diisopropyl fluorophosphatase, photoactive yellow protein and human aldose reductase. Furthermore, this method has several practical advantages, including the easier determination of the orientation of water molecules, hydroxyl groups and some amino-acid side chains

  13. Biological dosimetry of X-rays using in-Vitro micronucleus assay in human lymphocytes

    International Nuclear Information System (INIS)

    Micronuclei (Mn) are products of fragmented chromosomes which are recently being used as an alternative approach to the chromosome aberrations analysis for the estimation of biological absorbed dose in the case of occupationally exposed radiation workers including those working in industrial radiography, diagnostic radiology, nuclear medicine departments, as well as in nuclear installations. In the present work human blood samples were taken and after in- vitro irradiation with various doses of X-rays, in the dose range of 5-50 and 50-300 cgs were studied. Micronucleus test was performed using cytokinesis blocked cells. The best fit was obtained by linear quadratic model, Y=C +αD +βD2. Moreover we have observed X-ray induced micronucleus in lymphocytes from 7 exposed hospital X-ray workers. The micronucleus counts in these persons were 3-7 fold higher than those in control

  14. Biological effects of deuterium - depleted water

    International Nuclear Information System (INIS)

    Deuterium-depleted water (DDW) is represented by water that has an isotopic content smaller than 145 ppm D/(D + H). DDW production technique consists in the separation of deuterium from water by a continuous distillation process under pressure of about 133.3 mbar. The water used as raw material has a isotopic content of 145 ppm D/(D + H) and can be demineralized water, distillated water or condensed-steam. DDW results as a distillate with an isotopic deuterium content of 15-80 ppm, depending on the level we want to achieve. Beginning with 1996 the Institute of Cryogenics and Isotopic Technologies, DDW producer, co-operated with Romanian specialized institutes for studying the biological effects of DDW. The role of naturally occurring D in living organisms was examined by using DDW instead of natural water. These investigations led to the following conclusions: - DDW caused a tendency towards the increase of the basal tone, accompanied by the intensification of the vasoconstrictor effects of phenylefrine, noradrenaline and angiotensin; the increase of the basal tone and vascular reactivity produced by the DDW persists after the removal of the vascular endothelium; - Animals treated with DDW showed an increase of the resistance both to sublethal and lethal gamma radiation doses, suggesting a radioprotective action by the stimulation of non-specific immune defense mechanisms; - DDW stimulates immuno-defense reactions represented by the opsonic, bactericidal and phagocyte capacity of the immune system together with an increase in the number of poly-morphonuclear neutrophils; - Investigations regarding artificial reproduction of fish with DDW fecundated solutions confirmed favorable influence in embryo growth stage and resistance and following growth stages; - It was studied germination, growth and quantitative character variability in plants; one can remark the favorable influence of DDW on biological processes in plants in various ontogenetic stages. (authors)

  15. Food irradiation and its biological effects

    International Nuclear Information System (INIS)

    Irradiation of foods drew attention mostly in 1960s for disinfestation of food grains, spices and sprout inhibition in mainly potato and onion. γ-irradiation at 0.25 to 1 kGy dosage levels are usually used for irradiating grains, legumes, spices and sprout-prone vegetables. Irradiation of foods with in permissible dosage levels of 0.25 to 5 kGy is usually considered fairly safe from human consumption point of view not withstanding usual health concerns about its usage in foods. Irradiation of foods, in mostly solid or semi-solid form, at 5 kGy levels of γ-irradiation can achieve radicidation or, radiation equivalent of pasteurization and, if γ-irradiation is used at 10 kGy, it can achieve radappertization or, radiation equivalent of thermal commercial sterilization. However, the food industry uses γ-irradiation at 0.25 to 2 kGy only for mostly disinfestation of food grains/legumes, spices, sprout inhibition in potato and onion and, for surface sanitation of frozen fish, poultry and meat. Exposure to irradiation creates free radicals in foods that are capable of destroying some of the spoilage and pathogenic microflora but the same can also damage vitamins and enzymes besides creating some new harmful new chemical species, called unique radiolytic products (URPs), by combining with certain chemicals that a food may be laced with (like pesticides/fungicides). Exposure to high-energy electron beams are also known to create deleterious biological effects which may even lead to detection of trace amounts of radioactivity in the food. Some possible causes delineated for such harmful biological effects of irradiation include: irradiation induced vitamin deficiencies, the inactivity of enzymes in the foods, DNA damage and toxic radiolytic products in the foods. Irradiation, a non-thermal food preservation technique, has a role in salvaging enormous post harvest losses (25-30%) in developing economies to increase the per capita availability of foods. (author)

  16. Effects of stress and. beta. -funal trexamine pretreatment on morphine analgesia and opioid binding in rats

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.U.; Andrews, J.S.; Hiller, J.M.; Simon, E.J.; Holtzman, S.G.

    1987-12-28

    This study was essentially an in vivo protection experiment designed to test further the hypothesis that stress induces release of endogenous opiods which then act at opioid receptors. Rats that were either subjected to restraint stress for 1 yr or unstressed were injected ICV with either saline or 2.5 ..mu..g of ..beta..-funaltrexamine (..beta..-FNA), an irreversible opioid antagonist that alkylates the mu-opioid receptor. Twenty-four hours later, subjects were tested unstressed for morphine analgesia or were sacrificed and opioid binding in brain was determined. (/sup 3/H)D-Ala/sup 2/NMePhe/sup 4/-Gly/sup 5/(ol)enkephalin (DAGO) served as a specific ligand for mu-opioid receptors, and (/sup 3/H)-bremazocine as a general ligand for all opioid receptors. Rats injected with saline while stressed were significantly less sensitive to the analgesic action of morphine 24 hr later than were their unstressed counterparts. ..beta..-FNA pretreatment attenuated morphine analgesia in an insurmountable manner. Animals pretreated with ..beta..-FNA while stressed were significantly more sensitive to the analgesic effect of morphine than were animals that received ..beta..-FNA while unstressed. ..beta..-FNA caused small and similar decreases in (/sup 3/H)-DAGO binding in brain of both stressed and unstressed animals. 35 references, 2 figures, 2 tables.

  17. Effects of beta-adrenergic blockade on ventilation and gas exchange during incremental exercise.

    Science.gov (United States)

    Dodd, S; Powers, S; O'Malley, N; Brooks, E; Sommers, H

    1988-08-01

    Controversy exists concerning the effects of acute beta-adrenergic blockade on ventilation during exercise. Hence, the purpose of this study was to determine the effects of acute beta blockade on ventilation and gas exchange during incremental exercise. Nine male subjects underwent incremental exercise on a cycle ergometer (30 W.min-1) to exhaustion, with one trial being performed 60 min after the subject ingested propranolol hydrochloride (Inderal 1 mg.kg-1 BW) while the second test served as control. The treatment order was counterbalanced to preclude any ordering effect on the results, and 1 week separated the tests. Ventilation and gas exchange were monitored by open circuit techniques. No difference (p greater than 0.05) existed in VE, % Hb sat, VCO2, ventilatory threshold, and VE/VCO2 between treatments at the same exercise stage. VO2max was lowered from 3.82 to 3.26 l.min-1 (p less than 0.05) and HRmax was reduced from 190 to 150 bpm (p less than 0.05) as a result of beta blockade. These data suggested that acute beta blockade had no effect on exercise ventilation, but decreased HRmax at comparable work rates. In addition, VO2max and exercise time to exhaustion were hindered, probably due to beta blockade limitation of HRmax, and, thus, oxygen transport. PMID:3178619

  18. Effect of 10 Week Beta-Alanine Supplementation on Competition and Training Performance in Elite Swimmers

    Directory of Open Access Journals (Sweden)

    Louise M. Burke

    2012-10-01

    Full Text Available Although some laboratory-based studies show an ergogenic effect with beta-alanine supplementation, there is a lack of field-based research in training and competition settings. Elite/Sub-elite swimmers (n = 23 males and 18 females, age = 21.7 ± 2.8 years; mean ± SD were supplemented with either beta-alanine (4 weeks loading phase of 4.8 g/day and 3.2 g/day thereafter or placebo for 10 weeks. Competition performance times were log-transformed, then evaluated before (National Championships and after (international or national selection meet supplementation. Swimmers also completed three standardized training sets at baseline, 4 and 10 weeks of supplementation. Capillary blood was analyzed for pH, bicarbonate and lactate concentration in both competition and training. There was an unclear effect (0.4%; ±0.8%, mean, ±90% confidence limits of beta-alanine on competition performance compared to placebo with no meaningful changes in blood chemistry. While there was a transient improvement on training performance after 4 weeks with beta-alanine (−1.3%; ±1.0%, there was an unclear effect at ten weeks (−0.2%; ±1.5% and no meaningful changes in blood chemistry. Beta-alanine supplementation appears to have minimal effect on swimming performance in non-laboratory controlled real-world training and competition settings.

  19. Biological effects of radon in Drosophila

    International Nuclear Information System (INIS)

    The main objective of this investigation, is to study the biological effects of the Radon-222 at low dose in 'Drosophila melanogaster'. It is necessary to mention that these effects will analyze from the genetic point of view for: 1) To evaluate in which form the Radon-222 to low dose it influences in some genetic components of the adaptation in Drosophila, such as: fecundity, viability egg-adult and sex proportion. 2) To evaluate which is the genetic effect that induces the Radon to low dose by means of the SMART technique in Drosophila melanogaster, and this way to try of to identify which is the possible mechanism that causes the genetic damage to somatic level. The carried out investigation was divided in three stages: 1. Tests to the vacuum resistance. 2. Test of somatic mutation, and 3. Determination of the presence of radon daughters on the adult of Drosophila. It is necessary to point out that all the experiments were made by triplicate and in each one of them was placed detectors in preset places. Those obtained results are presented inside the 4 charts included in the present work. (Author)

  20. Methylprednisolone does not restore biological response in multiple sclerosis patients with neutralizing antibodies against interferon-beta

    DEFF Research Database (Denmark)

    Hesse, D; Frederiksen, J L; Koch-Henriksen, N;

    2009-01-01

    Background and purpose: Neutralizing antibodies (NAbs) appearing during treatment with Interferon-beta (IFN-beta) reduce or abolish bioactivity and therapeutic efficacy. Initial combination therapy with methylprednisolone (MP) may reduce the frequency of NAb positive patients. We hypothesized that...... Resistance Protein A (MxA) mRNA induction in whole blood using real time PCR. Results: At the end of study, median NAb NC was 92% in both groups. Eight patients (21%) in the MP group and four patients (11%) in the control group had regained an in vivo MxA response to IFN-beta (P = 0.35). Conclusions: Monthly...

  1. High-resolution, high-transmission soft x-ray spectrometer for the study of biological samples.

    Science.gov (United States)

    Fuchs, O; Weinhardt, L; Blum, M; Weigand, M; Umbach, E; Bär, M; Heske, C; Denlinger, J; Chuang, Y-D; McKinney, W; Hussain, Z; Gullikson, E; Jones, M; Batson, P; Nelles, B; Follath, R

    2009-06-01

    We present a variable line-space grating spectrometer for soft x-rays that covers the photon energy range between 130 and 650 eV. The optical design is based on the Hettrick-Underwood principle and tailored to synchrotron-based studies of radiation-sensitive biological samples. The spectrometer is able to record the entire spectral range in one shot, i.e., without any mechanical motion, at a resolving power of 1200 or better. Despite its slitless design, such a resolving power can be achieved for a source spot as large as (30 x 3000) microm2, which is important for keeping beam damage effects in radiation-sensitive samples low. The high spectrometer efficiency allows recording of comprehensive two-dimensional resonant inelastic soft x-ray scattering (RIXS) maps with good statistics within several minutes. This is exemplarily demonstrated for a RIXS map of highly oriented pyrolytic graphite, which was taken within 10 min. PMID:19566192

  2. High-resolution, high-transmission soft x-ray spectrometer for the study of biological samples

    International Nuclear Information System (INIS)

    We present a variable line-space grating spectrometer for soft x-rays that covers the photon energy range between 130 and 650 eV. The optical design is based on the Hettrick-Underwood principle and tailored to synchrotron-based studies of radiation-sensitive biological samples. The spectrometer is able to record the entire spectral range in one shot, i.e., without any mechanical motion, at a resolving power of 1200 or better. Despite its slitless design, such a resolving power can be achieved for a source spot as large as (30x3000) μm2, which is important for keeping beam damage effects in radiation-sensitive samples low. The high spectrometer efficiency allows recording of comprehensive two-dimensional resonant inelastic soft x-ray scattering (RIXS) maps with good statistics within several minutes. This is exemplarily demonstrated for a RIXS map of highly oriented pyrolytic graphite, which was taken within 10 min.

  3. Radon exposure of the skin: I. Biological effects

    Energy Technology Data Exchange (ETDEWEB)

    Charles, M W [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2007-09-15

    Radon progeny can plate out on skin and give rise to exposure of the superficial epidermis from alpha emitters Po-218 (7.7 MeV, range {approx}66 {mu}m) and Po-214 (6 MeV, range {approx}44 {mu}m). Dose rates from beta/gamma emitters Pb-214 and Bi-214 are low and only predominate at depths in excess of the alpha range. This paper reviews the evidence for a causal link between exposure from radon and its progeny, and deterministic and stochastic biological effects in human skin. Radiation induced skin effects such as ulceration and dermal atrophy, which require irradiation of the dermis, are ruled out for alpha irradiation from radon progeny because the target cells are considerably deeper than the range of alpha particles. They have not been observed in man or animals. Effects such as erythema and acute epidermal necrosis have been observed in a few cases of very high dose alpha particle exposures in man and after acute high dose exposure in animals from low energy beta radiations with similar depth doses to radon progeny. The required skin surface absorbed doses are in excess of 100 Gy. Such effects would require extremely high levels of radon progeny. They would involve quite exceptional circumstances, way outside the normal range of radon exposures in man. There is no definitive identification of the target cells for skin cancer induction in animals or man. The stem cells in the basal layer which maintain the epidermis are the most plausible contenders for target cells. The majority of these cells are near the end of the range of radon progeny alpha particles, even on the thinnest body sites. The nominal depth of these cells, as recommended by the International Commission on Radiological Protection (ICRP), is 70 {mu}m. There is evidence however that some irradiation of the hair follicles and/or the deeper dermis, as well as the inter-follicular epidermis, is also necessary for skin cancer induction. Alpha irradiation of rodent skin that is restricted to the

  4. Radon exposure of the skin: I. Biological effects

    International Nuclear Information System (INIS)

    Radon progeny can plate out on skin and give rise to exposure of the superficial epidermis from alpha emitters Po-218 (7.7 MeV, range ∼66 μm) and Po-214 (6 MeV, range ∼44 μm). Dose rates from beta/gamma emitters Pb-214 and Bi-214 are low and only predominate at depths in excess of the alpha range. This paper reviews the evidence for a causal link between exposure from radon and its progeny, and deterministic and stochastic biological effects in human skin. Radiation induced skin effects such as ulceration and dermal atrophy, which require irradiation of the dermis, are ruled out for alpha irradiation from radon progeny because the target cells are considerably deeper than the range of alpha particles. They have not been observed in man or animals. Effects such as erythema and acute epidermal necrosis have been observed in a few cases of very high dose alpha particle exposures in man and after acute high dose exposure in animals from low energy beta radiations with similar depth doses to radon progeny. The required skin surface absorbed doses are in excess of 100 Gy. Such effects would require extremely high levels of radon progeny. They would involve quite exceptional circumstances, way outside the normal range of radon exposures in man. There is no definitive identification of the target cells for skin cancer induction in animals or man. The stem cells in the basal layer which maintain the epidermis are the most plausible contenders for target cells. The majority of these cells are near the end of the range of radon progeny alpha particles, even on the thinnest body sites. The nominal depth of these cells, as recommended by the International Commission on Radiological Protection (ICRP), is 70 μm. There is evidence however that some irradiation of the hair follicles and/or the deeper dermis, as well as the inter-follicular epidermis, is also necessary for skin cancer induction. Alpha irradiation of rodent skin that is restricted to the epidermis does not

  5. Proteoglycan metabolism associated with mouse metanephric development: morphologic and biochemical effects of beta-D-xyloside

    International Nuclear Information System (INIS)

    Morphology and de novo incorporation of [35S]sulfate into proteoglycans were studied in fetal mouse kidneys at the onset of organogenesis. Branching morphogenesis and nephron development in organ culture and in vivo were associated with de novo synthesis of chondroitin-SO4 and heparan-SO4 proteoglycans. The role of proteoglycan metabolism in metanephrogenesis was then studied by analysis of the effects of p-nitrophenyl-beta-D-xylopyranoside (beta-D-xyloside) on renal development and proteoglycan metabolism. Incubation of fetal kidneys in beta-D-xyloside at concentrations of 1.0 and 0.5 mM, but not at 0.1 mM, caused inhibition of ureteric branching and markedly diminished synthesis of a large Mr 2.0 X 10(6) Da chondroitin-SO4 proteoglycan. Incorporation of [35S]sulfate was stimulated at all beta-D-xyloside concentrations, reflecting synthesis of xyloside initiated dermatan-35SO4 chains. In contrast to dramatic effects on chondroitin-SO4 synthesis and ureteric branching, beta-D-xyloside had no effect on heparan-SO4 synthesis or on development of the glomerulus and glomerular basement membrane. We thus characterize the proteoglycans synthesized early in the course of renal organogenesis and describe observations which suggest an association between metabolism of chondroitin-SO4 proteoglycan and development of the ureter

  6. Proteoglycan metabolism associated with mouse metanephric development: morphologic and biochemical effects of beta-D-xyloside

    Energy Technology Data Exchange (ETDEWEB)

    Platt, J.L.; Brown, D.M.; Granlund, K.; Oegema, T.R.; Klein, D.J.

    1987-10-01

    Morphology and de novo incorporation of (/sup 35/S)sulfate into proteoglycans were studied in fetal mouse kidneys at the onset of organogenesis. Branching morphogenesis and nephron development in organ culture and in vivo were associated with de novo synthesis of chondroitin-SO/sub 4/ and heparan-SO/sub 4/ proteoglycans. The role of proteoglycan metabolism in metanephrogenesis was then studied by analysis of the effects of p-nitrophenyl-beta-D-xylopyranoside (beta-D-xyloside) on renal development and proteoglycan metabolism. Incubation of fetal kidneys in beta-D-xyloside at concentrations of 1.0 and 0.5 mM, but not at 0.1 mM, caused inhibition of ureteric branching and markedly diminished synthesis of a large Mr 2.0 X 10(6) Da chondroitin-SO/sub 4/ proteoglycan. Incorporation of (/sup 35/S)sulfate was stimulated at all beta-D-xyloside concentrations, reflecting synthesis of xyloside initiated dermatan-/sup 35/SO/sub 4/ chains. In contrast to dramatic effects on chondroitin-SO/sub 4/ synthesis and ureteric branching, beta-D-xyloside had no effect on heparan-SO/sub 4/ synthesis or on development of the glomerulus and glomerular basement membrane. We thus characterize the proteoglycans synthesized early in the course of renal organogenesis and describe observations which suggest an association between metabolism of chondroitin-SO/sub 4/ proteoglycan and development of the ureter.

  7. Effect of transforming growth factor beta on synthesis of glycosaminoglycans by human lung fibroblasts

    International Nuclear Information System (INIS)

    The processes of lung growth, injury, and repair are characterized by alterations in fibroblast synthesis and interstitial distribution of extracellular matrix components. Transforming growth factor beta (TGF-beta), which is postulated to play a role in modulating lung repair, alters the distribution of several matrix components such as collagen and fibronectin. We studied the effect of TGF-beta on the synthesis and distribution of the various glycosaminoglycans (GAGs) and whether these effects may explain its role in lung repair. Human diploid lung fibroblasts (IMR-90) were exposed to various concentrations of TGF-beta (0-5 nM) for variable periods of time (0-18 h). Newly synthesized GAGs were labeled with either [3H]glucosamine or [35S]sulfate. Individual GAGs were separated by size exclusion chromatography after serial enzymatic and chemical digestions and quantitated using scintillation counting. There was a dose-dependent increase in total GAG synthesis with maximal levels detected after 6 h of exposure. This increase was noted in all individual GAG types measured and was observed in both the cell associated GAGs (cell-matrix fraction) as well as the GAGs released into the medium (medium fraction). In the cell-matrix fraction, TGF-beta increased the proportion of heparan sulfate that was membrane bound as well as the proportion of dermatan sulfate in the intracellular compartment. In the medium fraction, TGF-beta increased the proportion of hyaluronic acid, chondroitin sulfate and dermatan sulfate released. We conclude that the role of TGF-beta in lung growth and repair may be related to increased synthesis of GAGs by human lung fibroblasts as well as alterations in the distribution of individual GAGs

  8. Effect of transforming growth factor beta on synthesis of glycosaminoglycans by human lung fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Dubaybo, B.A.; Thet, L.A. (Veterans Administration Medical Center, Allen Park, MI (USA))

    1990-09-01

    The processes of lung growth, injury, and repair are characterized by alterations in fibroblast synthesis and interstitial distribution of extracellular matrix components. Transforming growth factor beta (TGF-beta), which is postulated to play a role in modulating lung repair, alters the distribution of several matrix components such as collagen and fibronectin. We studied the effect of TGF-beta on the synthesis and distribution of the various glycosaminoglycans (GAGs) and whether these effects may explain its role in lung repair. Human diploid lung fibroblasts (IMR-90) were exposed to various concentrations of TGF-beta (0-5 nM) for variable periods of time (0-18 h). Newly synthesized GAGs were labeled with either (3H)glucosamine or (35S)sulfate. Individual GAGs were separated by size exclusion chromatography after serial enzymatic and chemical digestions and quantitated using scintillation counting. There was a dose-dependent increase in total GAG synthesis with maximal levels detected after 6 h of exposure. This increase was noted in all individual GAG types measured and was observed in both the cell associated GAGs (cell-matrix fraction) as well as the GAGs released into the medium (medium fraction). In the cell-matrix fraction, TGF-beta increased the proportion of heparan sulfate that was membrane bound as well as the proportion of dermatan sulfate in the intracellular compartment. In the medium fraction, TGF-beta increased the proportion of hyaluronic acid, chondroitin sulfate and dermatan sulfate released. We conclude that the role of TGF-beta in lung growth and repair may be related to increased synthesis of GAGs by human lung fibroblasts as well as alterations in the distribution of individual GAGs.

  9. Effect of. beta. -endorphin on catecholamine levels in rat hypothalamus and cerebral cortex

    Energy Technology Data Exchange (ETDEWEB)

    Slavnov, V.N.; Valueva, G.V.; Markov, V.V.; Luchitskii, E.V.

    1986-10-01

    The authors studied the effect of beta-endorphin on catecholamine concentrations in the hypothalmus and cerebral cortex in rats, as a contribution to the explanation of the mechanism of action of this peptide on certain pituitary trophic functions. Concentrations of dopamine, noradrenalin, and adrenalin were determined by a radioenzymatic method. A Mark 3 scintillation system was used for radiometric investigation of the samples. The results of these experiments indicate that beta-endorphin has a marked effect on brain catecholamine levels mainly in the hypothalamus.

  10. Combine-ARMS: a rapid and cost-effective protocol for molecular characterization of beta-thalassemia in Malaysia.

    Science.gov (United States)

    Tan, K L; Tan, J A; Wong, Y C; Wee, Y C; Thong, M K; Yap, S F

    2001-01-01

    Beta-thalassemia major patients have chronic anemia and are dependent on blood transfusions to sustain life. Molecular characterization and prenatal diagnosis of beta3-thalassemia is essential in Malaysia because about 4.5% of the population are heterozygous carriers for beta-thalassemia. The high percentage of compound heterozygosity (47.62%) found in beta-thalassemia major patients in the Thalassaemia Registry, University of Malaya Medical Centre (UMMC), Malaysia, also supports a need for rapid, economical, and sensitive protocols for the detection of beta-thalassemia mutations. Molecular characterization of beta-thalassemia mutations in Malaysia is currently carried out using ARMS, which detects a single beta-thalassemia mutation per PCR reaction. We developed and evaluated Combine amplification refractory mutation system (C-ARMS) techniques for efficient molecular detection of two to three beta-thalassemia mutations in a single PCR reaction. Three C-ARMS protocols were evaluated and established for molecular characterization of common beta-thalassemia mutations in the Malay and Chinese ethnic groups in Malaysia. Two C-ARMS protocols (cd 41-42/IVSII #654 and -29/cd 71-72) detected the beta-thalassemia mutations in 74.98% of the Chinese patients studied. The CARMS for cd 41-42/IVSII #654 detected beta-thalassemia mutations in 72% of the Chinese families. C-ARMS for cd 41-42/IVSI #5/cd 17 allowed detection of beta-thalassemia mutations in 36.53% of beta-thalassemia in the Malay patients. C-ARMS for cd 41-42/IVSI #5/cd 17 detected beta-thalassemia in 45.54% of the Chinese patients. We conclude that C-ARMS with the ability to detect two to three mutations in a single reaction provides more rapid and cost-effective protocols for beta-thalassemia prenatal diagnosis and molecular analysis programs in Malaysia. PMID:11336396

  11. Intergrown new zeolite beta polymorphs with interconnected 12-ring channels solved by combining electron crystallography and single-crystal X-ray diffraction

    KAUST Repository

    Yu, Zhengbao

    2012-10-09

    Two new polymorphs of zeolite beta, denoted as SU-78A and SU-78B, were synthesized by employing dicyclohexylammonium hydroxides as organic structure-directing agents. The structure was solved by combining transmission electron microscopy and single-crystal X-ray diffraction. SU-78 is an intergrowth of SU-78A and SU-78B and contains interconnected 12-ring channels in three directions. The two polymorphs are built from the same building layer, similar to that for the zeolite beta family. The layer stacking in SU-78, however, is different from those in zeolite beta polymorph A, B, and C, showing new zeolite framework topologies. SU-78 is thermally stable up to 600 °C. © 2012 American Chemical Society.

  12. Expression, purification, crystallization, and preliminary X-ray crystallographic analysis of OXA-17, an extended-spectrum {beta}-lactamase conferring severe antibiotic resistance

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. H., E-mail: msgjhlee@mju.ac.kr; Sohn, S. G., E-mail: sgsohn@mju.ac.kr; Jung, H. I., E-mail: jhinumber1@hanmail.net; An, Y. J., E-mail: anyj0120@hanmail.net; Lee, S. H., E-mail: sangheelee@mju.ac.kr [Myongji University, Drug Resistance Proteomics Laboratory, Department of Biological Sciences (Korea, Republic of)

    2013-07-15

    OXA-17, an extended-spectrum {beta}-lactamase (ESBL) conferring severe antibiotic resistance, hydrolytically inactivates {beta}-lactam antibiotics, inducing a lack of eradication of pathogenic bacteria by oxyimino {beta}-lactams and not helping hospital infection control. Thus, the enzyme is a potential target for developing antimicrobial agents against pathogens producing ESBLs. OXA-17 was purified and crystallized at 298 K. X-ray diffraction data from OXA-17 crystal have been collected to 1.85 A resolution using synchrotron radiation. The crystal of OXA-17 belongs to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 48.37, b = 101.12, and c = 126.07 A. Analysis of the packing density shows that the asymmetric unit probably contains two molecules with a solvent content of 54.6%.

  13. 3D nanoscale imaging of biological samples with laboratory-based soft X-ray sources

    Science.gov (United States)

    Dehlinger, Aurélie; Blechschmidt, Anne; Grötzsch, Daniel; Jung, Robert; Kanngießer, Birgit; Seim, Christian; Stiel, Holger

    2015-09-01

    In microscopy, where the theoretical resolution limit depends on the wavelength of the probing light, radiation in the soft X-ray regime can be used to analyze samples that cannot be resolved with visible light microscopes. In the case of soft X-ray microscopy in the water-window, the energy range of the radiation lies between the absorption edges of carbon (at 284 eV, 4.36 nm) and oxygen (543 eV, 2.34 nm). As a result, carbon-based structures, such as biological samples, posses a strong absorption, whereas e.g. water is more transparent to this radiation. Microscopy in the water-window, therefore, allows the structural investigation of aqueous samples with resolutions of a few tens of nanometers and a penetration depth of up to 10μm. The development of highly brilliant laser-produced plasma-sources has enabled the transfer of Xray microscopy, that was formerly bound to synchrotron sources, to the laboratory, which opens the access of this method to a broader scientific community. The Laboratory Transmission X-ray Microscope at the Berlin Laboratory for innovative X-ray technologies (BLiX) runs with a laser produced nitrogen plasma that emits radiation in the soft X-ray regime. The mentioned high penetration depth can be exploited to analyze biological samples in their natural state and with several projection angles. The obtained tomogram is the key to a more precise and global analysis of samples originating from various fields of life science.

  14. Effects of. gamma. -irradiation on. beta. -pinene content and germination in grapefruit

    Energy Technology Data Exchange (ETDEWEB)

    Uchiyama, Sadao; Kawamura, Yoko; Saito, Yukio; Nagashima, Kimiyo.

    1988-12-01

    Effects of ..gamma..-irradiation on ..beta..-pinene content and germination in grapefruit were investigated in order to develop a method to identify ..gamma..-irradiated grapefruit. ..beta..-Pinene is a component of essential oil in grapefruit and was reported to be susceptible to ..gamma..-irradiation. However, it was not degraded by irradiation (30 to 200 krad) in this experiment. When grapefruit irradiated at 50 krad were stored at 10degC for 2 months, no change of ..beta..-pinene content was found. ..beta..-Pinene itself was also stable to ..gamma..-irradiation at 1 Mrad. Thus, identification of irradiated grapefruit from the amount of ..beta..-pinene was impossible. On the other hand, the effect of ..gamma..-irradiation on radicle elongation was small but that on plumule expansion was so large as to prevent shooting in grapefruit irradiated even at 30 krad. Therefore it should be possible to identify ..gamma..-irradiated grapefruit by a germination method.

  15. Protective Effects of Beta Glucan and Gliclazide on Brain Tissue and Sciatic Nerve of Diabetic Rats Induced by Streptozosin

    OpenAIRE

    Alp, Harun; Varol, Sefer; Celik, Muhammet Murat; Altas, Murat; Evliyaoglu, Osman; Tokgoz, Orhan; Tanrıverdi, Mehmet Halis; Uzar, Ertugrul

    2012-01-01

    There have not been yet enough studies about effects of beta glucan and gliclazide on oxidative stress created by streptozotocin in the brain and sciatic nerve of diabetic rats. The aim of this paper was to investigate the antioxidant effects of gliclazide and beta glucan on oxidative stress and lipid peroxidation created by streptozotosin in brain and sciatic nerve. Total of 42 rats were divided into 6 groups including control, diabetic untreated (DM) (only STZ, diabetic), STZ (DM) + beta gl...

  16. E. Biological effects of radiation on man

    International Nuclear Information System (INIS)

    This report firstly summarises information on the biological hazards of radiation and their relation to radiation dose, and hence estimates the biological risks associated with nuclear power production. Secondly, it describes the basis and present status of radiation protection standards in the nuclear power industry

  17. What Makes Biology Learning Difficult and Effective: Students' Views

    Science.gov (United States)

    Cimer, Atilla

    2012-01-01

    The present study aims to determine the biological topics that students have difficulties learning, the reasons why secondary school students have difficulties in learning biology, and ways to improve the effectiveness of students' biology learning. For these purposes, a self-administered questionnaire including three open-ended questions was…

  18. Effects of modified {beta}-cyclodextrin on thermal stability and conformation of lysozyme

    Energy Technology Data Exchange (ETDEWEB)

    Kamiyama, Tadashi, E-mail: kamiyama@chem.kindai.ac.jp [Department of Chemistry, School of Science and Engineering, Kinki University, Kowakae 3-4-1, Higashi-Osaka, Osaka 577-8502 (Japan); Satoh, Megumi; Tateishi, Takahiro; Nojiri, Tomoaki; Takeuchi, Daisuke; Kimura, Takayoshi [Department of Chemistry, School of Science and Engineering, Kinki University, Kowakae 3-4-1, Higashi-Osaka, Osaka 577-8502 (Japan)

    2012-03-20

    Highlights: Black-Right-Pointing-Pointer Effects of cyclodextrin on stability and conformation of lysozyme were clarified. Black-Right-Pointing-Pointer The CD influences the hydrophobic interaction of lysozyme by the inclusion. Black-Right-Pointing-Pointer The CD relatively destabilized the folded state by stabilizing the unfolded state. Black-Right-Pointing-Pointer The destabilization depends on the concentration and the substituent of CD. Black-Right-Pointing-Pointer The conformation of lysozyme was more spread at unfolded state by inclusion of CD. - Abstract: Effects of cyclic oligosaccharide cyclodextrin (CD) on stability and conformation of lysozyme were clarified thermodynamically and rheologically by DSC, viscosity, and circular dichroism measurements. The modified {beta}-CD relatively destabilized the folded state of lysozyme by stabilizing the unfolded state due to inclusion of hydrophobic part into the hydrophobic interior of CD. The order of higher destabilization effect was acetyl-{beta}-CD > methyl-{beta}-CD > hydroxypropyl-{beta}-CD. Apparent number of bound CD to unfolded state for methyl-, hydroxypropyl-, and acetyl-{beta}-CD is 6.7 {+-} 0.7, 4.2 {+-} 1.1, and 18.6 {+-} 4.3 and the binding constant is 5.5 {+-} 0.8, 6.7 {+-} 2.4, and 4.4 {+-} 1.2 L mol{sup -1}, respectively. The viscosity for unfolded state was increased with an increase in the each modified {beta}-CD concentration, suggesting that the inclusion of CD on a part of hydrophobic core at unfolded state leads to break the hydrophobic core, then lysozyme would be more spread structure. The substituent of CD can accelerate instability by directly breaking hydrogen bond and/or can restrain instability by increase in hydrophobic interaction. The fact that the each modified CDs has different destabilization effect shows a possibility to control the stability of protein by the substitution of CD.

  19. Effects of endocrine disruptors on genes associated with 17beta-estradiol metabolism and excretion.

    Science.gov (United States)

    Hanet, Nathalie; Lancon, Allan; Delmas, Dominique; Jannin, Brigitte; Chagnon, Marie-Christine; Cherkaoui-Malki, Moustapha; Latruffe, Norbert; Artur, Yves; Heydel, Jean-Marie

    2008-11-01

    In order to provide a global analysis of the effects of endocrine disruptors on the hormone cellular bioavailability, we combined 17beta-estradiol (E2) cellular flow studies with real-time PCR and Western blot expression measurements of genes involved in the hormone metabolism and excretion. Three endocrine disruptors commonly found in food were chosen for this study, which was conducted in the estrogen receptor (ER) negative hepatoblastoma HepG2 cell line: bisphenol A (BPA), genistein (GEN) and resveratrol (RES). We showed that 24 h after a single dose treatment with genistein, resveratrol or bisphenol A, the expression of ATP-binding cassette transporters (the multidrug resistance or MDR, and the multidrug resistance associated proteins or MRP) uridine diphosphate-glucuronosyltransferases (UGT) and/or sulfotransferases (ST) involved in 17beta-estradiol elimination process were significantly modulated and that 17beta-estradiol cellular flow was modified. Resveratrol induced MDR1 and MRP3 expressions, bisphenol A induced MRP2 and MRP3 expressions, and both enhanced 17beta-estradiol efflux. Genistein, on the other hand, inhibited ST1E1 and UGT1A1 expressions, and led to 17beta-estradiol cellular retention. Thus, we demonstrate that bisphenol A, genistein and resveratrol modulate 17beta-estradiol cellular bioavailability in HepG2 and that these modulations most probably involve regulations of 17beta-estradiol phase II and III metabolism proteins. Up to now, the estrogenicity of environmental estrogenic pollutants has been based on the property of these compounds to bind to ERs. Our results obtained with ER negative cells provide strong evidence for the existence of ER-independent pathways leading to endocrine disruption. PMID:18634814

  20. Space Radiation Quality Factors and the Delta Ray Dose and Dose-Rate Reduction Effectiveness Factor.

    Science.gov (United States)

    Cucinotta, Francis A; Cacao, Eliedonna; Alp, Murat

    2016-03-01

    In this paper, the authors recommend that the dose and dose-rate effectiveness factor used for space radiation risk assessments should be based on a comparison of the biological effects of energetic electrons produced along a cosmic ray particles path in low fluence exposures to high dose-rate gamma-ray exposures of doses of about 1 Gy. Methods to implement this approach are described. PMID:26808878

  1. Internal {alpha} activity: localisation, compositional associations and effects on OSL signals in quartz approaching {beta} saturation

    Energy Technology Data Exchange (ETDEWEB)

    Burbidge, C.I. [Instituto Tecnologico e Nuclear, Sacavem (Portugal)], E-mail: christoph@itn.pt; Dias, M.I.; Prudencio, M.I. [Instituto Tecnologico e Nuclear, Sacavem (Portugal); Rebelo, L.P. [DGM, INETI, Departamento de Geologia Marinha, Alfragide (Portugal); Cardoso, G. [Instituto Tecnologico e Nuclear, Sacavem (Portugal); Brito, P. [DGM, INETI, Departamento de Geologia Marinha, Alfragide (Portugal)

    2009-05-15

    Luminescence signals from hydrofluoric acid etched grains of quartz from Mozambican dunes were investigated in terms of elemental impurities, structural defects, and their relationship to internal {alpha} activity, to examine the potential for this to cause differences in signal levels obtainable from natural and laboratory irradiated samples. Optical and scanning electron microscopy (SEM), X-ray fluorescence (XRF) and instrumental neutron activation analysis (INAA) indicated the presence of various types of quartz and mineralogical inclusions. A spatial association of Th and U with Fe in structural defects was observed. Fe concentrations and inclusion sizes indicated that internal {alpha} dose rate would affect the defects that contained these impurities, but would be insignificant to the bulk quartz. A broad range of optically sensitive thermoluminescence (TL) peaks were observed from this material, and indicated a preheating regime of 260 deg. C for 30 s to minimise effects of the observed inclusions and defects on absorbed dose determinations by optically stimulated luminescence (OSL). Growth in OSL with dose from etched coarse grains preheated in this way approached saturation by 332 Gy of {beta} irradiation ({sup 90}Sr/{sup 90}Y) and by 4 kGy of {alpha} irradiation (E {approx} 3.5 MeV: approximate natural soil spectrum average, using converted dose rate from {sup 241}Am). This indicated {alpha}-efficiency (k{sub eff}) at saturation of less than 0.08. However, the OSL decay curves contained a small 'medium' component. Structural defects introduced by milling the grains produced a larger 'medium' component with a similar decay rate under optical stimulation, which exhibited high saturation doses (>32 kGy{alpha}, >8.4 kGy{beta}) and {alpha}-efficiency (k{sub eff} = 0.34). Maximum dose normalised OSL signals from the milled material greatly exceeded those obtainable from the whole etched grains. It is inferred that the presence of structural

  2. The late biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    Full text: The principal objective of the symposium was to review the current status of understanding of the late biological effects of ionizing radiation from external and internal sources. A second objective was to critically evaluate information obtained from epidemiological studies of human population groups as well as from animal experimentation in order to provide a solid scientific basis upon which problems of current concern, such as radiation protection standards and risk-benefit analysis, could be deliberated. Eighty-one papers were presented in 10 sessions which covered epidemiological studies of late effects in human populations exposed to internal and/or external ionizing radiation; quantitative and qualitative data from animal experimentation of late effects; methodological problems and modern approaches; factors influencing susceptibility or expression of late radiation injury; comparative evaluation of late effects induced by radiation and other environmental pollutants, and problems of risk assessment. In addition, there were two evening sessions for free discussion of problems of interpreting animal data, and of the epidemiological studies of occupationally exposed populations. Reports on atomic bomb survivors showed that these epidemiological studies are providing dependable data, such as dose-related excess infant mortality. The reports also revealed the need for consensus in the method employed in the interpretation of data. That was also the case with studies on occupationally exposed populations at Hanford plant, where disparate results were presented on radiation-induced neoplasia among radiation workers. These data are, however, considered not so significant in relative terms when compared to risks involved in other industries. It was recommended that national registry systems for the dosimetry and medical records of radiation workers be established and co-ordinated internationally in order to facilitate reliable epidemiological

  3. X-ray structure analyses of biological molecules and particles in Japan. A brief history and future prospect

    International Nuclear Information System (INIS)

    In Japan, X-ray structure analyses of molecules and particles from biology started in the 1970s. The structure analysis methods have been developed through the innovation of various techniques in advance, and have contributed for understanding the elementary and microscopic processes in life. Here we summarize briefly the history of X-ray structure analyses for structural biology in Japan and think about the prospect. (author)

  4. Effect of x-rays on chromosome 21 nondisjunction

    International Nuclear Information System (INIS)

    In a series of 156 females and 149 males with a Down syndrome (DS) child, a case-control study was performed to evaluate the effect of abdominal-pelvic exposure to diagnostic x-rays prior to conception on nondisjunction (ND). Cytogenetic analysis using QFQ banding allowed unequivocal identification of ND parents as cases. Partners of ND parents were treated as control group. Odds ratio for the association of x-rays exposure and ND occurrence (stratified for sex and age) was 1.85 (borderline to significance: with a 95% confidence interval 1-3.44). Such an association appeared highly significant in older fathers and borderline to significant in younger mothers, when age groups were analyzed separately. By comparing mean parental ages at birth of the propositus, the prevalence of exposure to x-rays appeared moderately associated with aging in control parents of both sexes. Furthermore, the mean age of unexposed ND parents of paternally derived SD cases was the same as the referent population's, suggesting that age is not a risk factor for ND in the male, except for being associated with increasing exposure risk. Conversely, risk attributable to x-rays exposure in the female appears to be progressively diluted with increasing age, by strongly age-dependent high risk, presumably due to biologic factors that are not affected by environmental exposure

  5. Accounting for biological effectiveness in radiological protection

    International Nuclear Information System (INIS)

    Relative biological effectiveness (RBE) presents a practical problem to radiological protection when attempts are made to ensure that the assessed risks from different types of radiation and different modes of exposure to radiation are commensurate with one another. Unfortunately, the theoretical understanding of RBE is still in the stage of competing explanations and hypotheses. Furthermore, the division of the concept of dose equivalent into a set of concepts for risk assessment and another set for measurement and control has introduced conflicting requirements of a practical nature that are difficult to resolve. Many of those working in radiobiology and radiation protection have perceived the need to increase the quality factors for photon and neutron radiations. It may be more reasonable to change the quality factors for neutrons than for other radiations. The advantages and disadvantages of different methods for accommodating such changes within the dose-equivalent concepts are to be examined. The method of accommodating such a change that has the least practical disadvantages is to increase the quality factors for all secondary particles produced in tissue by neutron radiations by a constant factor. The only disadvantage would be the perception that the quality factors for these secondary particles were not treated in a consistent fashion for all types of ionising radiation. (author)

  6. Biologically based multistage modeling of radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    William Hazelton; Suresh Moolgavkar; E. Georg Luebeck

    2005-08-30

    This past year we have made substantial progress in modeling the contribution of homeostatic regulation to low-dose radiation effects and carcinogenesis. We have worked to refine and apply our multistage carcinogenesis models to explicitly incorporate cell cycle states, simple and complex damage, checkpoint delay, slow and fast repair, differentiation, and apoptosis to study the effects of low-dose ionizing radiation in mouse intestinal crypts, as well as in other tissues. We have one paper accepted for publication in ''Advances in Space Research'', and another manuscript in preparation describing this work. I also wrote a chapter describing our combined cell-cycle and multistage carcinogenesis model that will be published in a book on stochastic carcinogenesis models edited by Wei-Yuan Tan. In addition, we organized and held a workshop on ''Biologically Based Modeling of Human Health Effects of Low dose Ionizing Radiation'', July 28-29, 2005 at Fred Hutchinson Cancer Research Center in Seattle, Washington. We had over 20 participants, including Mary Helen Barcellos-Hoff as keynote speaker, talks by most of the low-dose modelers in the DOE low-dose program, experimentalists including Les Redpath (and Mary Helen), Noelle Metting from DOE, and Tony Brooks. It appears that homeostatic regulation may be central to understanding low-dose radiation phenomena. The primary effects of ionizing radiation (IR) are cell killing, delayed cell cycling, and induction of mutations. However, homeostatic regulation causes cells that are killed or damaged by IR to eventually be replaced. Cells with an initiating mutation may have a replacement advantage, leading to clonal expansion of these initiated cells. Thus we have focused particularly on modeling effects that disturb homeostatic regulation as early steps in the carcinogenic process. There are two primary considerations that support our focus on homeostatic regulation. First, a number of

  7. 2.3.1 Biological Effects of Ionizing Radiations

    Science.gov (United States)

    Kaul, A.

    This document is part of Subvolume A 'Fundamentals and Data in Radiobiology, Radiation Biophysics, Dosimetry and Medical Radiological Protection' of Volume 7 'Medical Radiological Physics' of Landolt-Börnstein - Group VIII 'Advanced Materials and Technologies'. It contains the Subsection '2.3.1 Biological Effects of Ionizing Radiations' of the Section '2.3 Biological Effects' of the Chapter '2 Radiation and Biological Effects' with the comtents:

  8. Analysis of biological slurry samples by total x-ray fluorescence after in situ microwave digestion

    International Nuclear Information System (INIS)

    Biological slurry samples were analyzed by total reflection x-ray fluorescence (TXRF) after an in situ microwave digestion procedure on the quartz reflector. This method lead to the removal of the matrix by the digestion and permits the enrichment of the analites by using sample amounts higher than those normally used in TXRF for the thin layer requirement since the organic matrix is removed. In consequence, the pre-concentration of sample is performed and the detection capability is increased by a quasi direct method. The samples analyzed were the international IAEA blood standard, the SRM bovine liver 1577-a standard and fresh onion tissues. Slurries were prepared in three ways: a.- weighing a sample amount on the reflector and adding suprapure nitric acid and internal standard followed by microwave digestion, b.-weighing a sample amount and water with an appropriate concentration of the internal standard in an Eppendorf vial, taking then an aliquot to the quartz reflector for microwave digestion with suprapure nitric acid, c.- weighing a sample amount of fresh tissue, homogenising with high speed homegenator to obtain a slurry sample which can be diluted in an ependorf vial with water an the internal standard. Then an aliquot is taken to the reflector for microwave digestion with suprapure nitric acid. Further details of sample preparation procedures will be discussed during presentation. The analysis was carried out in a Canberra spectrometer using the Kalpha lines of the Ag and Mo tubes. The elements Ca, K, Fe, Cu, Zn, Se, Mn, Rb, Br, Sr were determined. The effect of the preparation procedure was evaluated by the accuracy and precision of the results for each element and the percent of recovery. (author)

  9. Distortion of pulse height spectra due to absorbers in the measurement of low-energy beta-rays with a silicon detector

    CERN Document Server

    Yamamoto, H; Norimura, T; Katase, A

    2002-01-01

    In measurement of beta-rays from sup 1 sup 4 C with a silicon semiconductor detector, pulse height spectra are observed to change by insertion of absorbers between the source and the detector. An obvious broad peak appears in the spectra by the insertion. An increase in the absorber thickness reduces the peak height, and shifts the peak position to the higher energy side in the spectra. On the other hand, the increase in the distance between the source and the absorber also reduces the peak height, but does not move the position of the peak. The absorption curve derived from these results shows its particular shape corresponding to the respective position of the absorber. Therefore, the distortion of the pulse height spectrum for low-energy beta-rays depends not only on the thickness of the absorber but also on its position between the source and the detector. (author)

  10. Effects of in ovo feeding of carbohydrates and beta-hydroxy-beta-methylbutyrate on the development of chicken intestine.

    Science.gov (United States)

    Tako, E; Ferket, P R; Uni, Z

    2004-12-01

    Early development of the digestive tract is crucial for achieving maximal growth and development of chickens. Because the late-term embryo naturally consumes the amniotic fluids, insertion of a nutrient solution into the embryonic amniotic fluid [in ovo (IO) feeding] may enhance development. This study examined the effect of IO feeding on d 17.5 of incubation of carbohydrates (CHO) and beta-hydroxy-beta-methylbutyrate (HMB) on small intestinal development of chickens during the pre and posthatch periods. Results shows that 48 h post-IO feeding procedure all IO feeding treatments exhibited increased villus width and surface area compared with the control group. At d 3 posthatch the surface area of an average villi was increased by 45% for the HMB IO group and by 33% for the CHO and CHO+HMB IO groups compared with controls (noninjected fertile eggs). The activity of jejunal sucrase-isomaltase (SI) was higher (P < 0.05) 48 h after IO feeding in all the IO fed embryos, whereas at day of hatch and at d 3 the CHO+HMB IO group had the highest maltase activity (P < 0.05), which was approximately 50% greater than control embryos. These observations indicated that small intestines of IO fed hatchlings were functionally at a similar stage of development as a conventionally fed 2-d-old chick. Body weight of all IO fed hatchlings was greater than controls, and these differences (P < 0.05) were sustained until the end of the experiment (10 d). At d 10 chicks that were IO fed with CHO had BW that were 2.2% higher, whereas HMB and CHO+HMB IO fed chicks showed 5 to 6.2% BW increase, respectively, compared with controls. The current study shows that the administration of exogenous nutrients into the amnion enhanced intestinal development by increasing the size of the villi and by increasing the intestinal capacity to digest disaccharides. This advantage probably leads to higher BW in IO fed chicks. PMID:15615016

  11. IGF-I and TGF-beta1 have distinct effects on phenotype and proliferation of intestinal fibroblasts.

    Science.gov (United States)

    Simmons, James G; Pucilowska, Jolanta B; Keku, Temitope O; Lund, P Kay

    2002-09-01

    Insulin-like growth factor I (IGF-I) and transforming growth factor-beta1 (TGF-beta1) are upregulated in myofibroblasts at sites of fibrosis in experimental enterocolitis and in Crohn's disease (CD). We compared the sites of expression of IGF-I and TGF-beta1 in a rat peptidoglycan-polysaccharide (PG-PS) model of chronic granulomatous enterocolitis and fibrosis. We used the human colonic CCD-18Co fibroblast/myofibroblast cell line to test the hypothesis that TGF-beta1 and IGF-I interact to regulate proliferation, collagen synthesis, and activated phenotype typified by expression of alpha-smooth muscle actin and organization into stress fibers. IGF-I potently stimulated while TGF-beta1 inhibited basal DNA synthesis. TGF-beta1 and IGF-I each had similar but not additive effects to induce type I collagen. TGF-beta1 but not IGF-I potently stimulated expression of alpha-smooth muscle actin and stress fiber formation. IGF-I in combination with TGF-beta1 attenuated stress fiber formation without reducing alpha-smooth muscle actin expression. Stress fibers were not a prerequisite for increased collagen synthesis. TGF-beta1 upregulated IGF-I mRNA, which led us to examine the effects of IGF-I in cells previously activated by TGF-beta1 pretreatment. IGF-I potently stimulated proliferation of TGF-beta1-activated myofibroblasts without reversing activated fibrogenic phenotype. We conclude that TGF-beta1 and IGF-I both stimulate type I collagen synthesis but have differential effects on activated phenotype and proliferation. We propose that during intestinal inflammation, regulation of activated phenotype and proliferation may require sequential actions of TGF-beta1 and IGF-I, but they may act in concert to increase collagen deposition. PMID:12181198

  12. Stereoselective and nonstereoselective effects of ibuprofen enantiomers on mitochondrial beta-oxidation of fatty acids

    International Nuclear Information System (INIS)

    The effects of the R-(-) and S-(+)ibuprofen enantiomers were first studied in vitro with mouse liver mitochondria incubated in the presence of various concentrations of exogenous coenzyme A. In the presence of a low concentration of coenzyme A (2.5 microM), the R-(-)enantiomer (which forms an acylcoenzyme A) inhibited stereoselectively the beta oxidation of [1-14C]palmitic acid but not that of [1-14C]palmitoyl-L-carnitine (which can directly enter the mitochondria). In the presence, however, of a concentration of coenzyme A (50 microM) reproducing that present in liver cell cytosol, both enantiomers (2 mM) slightly inhibited the beta oxidation of [1-14C]palmitic acid and markedly inhibited the beta oxidation of [1-14C]octanoic acid and [1-14C]butyric acid. In vivo, both enantiomers (1 mmol.kg-1) similarly inhibited the formation of [14C]CO2 from [1-14C]fatty acids. Both enantiomers similarly decreased plasma ketone bodies. Both similarly increased hepatic triglycerides, and both produced mild microvesicular steatosis of the liver. We conclude that both ibuprofen enantiomers inhibit beta oxidation of fatty acids in vitro and in vivo. In addition, the R-(-)enantiomer may stereoselectively sequester coenzyme A; at low concentrations of coenzyme A in vitro, this may stereoselectively inhibit the mitochondrial uptake and beta oxidation of long chain fatty acids

  13. Stereoselective and nonstereoselective effects of ibuprofen enantiomers on mitochondrial beta-oxidation of fatty acids

    Energy Technology Data Exchange (ETDEWEB)

    Freneaux, E.; Fromenty, B.; Berson, A.; Labbe, G.; Degott, C.; Letteron, P.; Larrey, D.; Pessayre, D. (Unite de Recherches de Physiolopathologie Hepatique (INSERM U-24), Hopital Beaujon, Clichy (France))

    1990-11-01

    The effects of the R-(-) and S-(+)ibuprofen enantiomers were first studied in vitro with mouse liver mitochondria incubated in the presence of various concentrations of exogenous coenzyme A. In the presence of a low concentration of coenzyme A (2.5 microM), the R-(-)enantiomer (which forms an acylcoenzyme A) inhibited stereoselectively the beta oxidation of (1-{sup 14}C)palmitic acid but not that of (1-{sup 14}C)palmitoyl-L-carnitine (which can directly enter the mitochondria). In the presence, however, of a concentration of coenzyme A (50 microM) reproducing that present in liver cell cytosol, both enantiomers (2 mM) slightly inhibited the beta oxidation of (1-{sup 14}C)palmitic acid and markedly inhibited the beta oxidation of (1-{sup 14}C)octanoic acid and (1-{sup 14}C)butyric acid. In vivo, both enantiomers (1 mmol.kg-1) similarly inhibited the formation of ({sup 14}C)CO{sub 2} from (1-{sup 14}C)fatty acids. Both enantiomers similarly decreased plasma ketone bodies. Both similarly increased hepatic triglycerides, and both produced mild microvesicular steatosis of the liver. We conclude that both ibuprofen enantiomers inhibit beta oxidation of fatty acids in vitro and in vivo. In addition, the R-(-)enantiomer may stereoselectively sequester coenzyme A; at low concentrations of coenzyme A in vitro, this may stereoselectively inhibit the mitochondrial uptake and beta oxidation of long chain fatty acids.

  14. The Effects of Tai Chi Practice on Intermuscular Beta Coherence and the Rubber Hand Illusion.

    Science.gov (United States)

    Kerr, Catherine E; Agrawal, Uday; Nayak, Sandeep

    2016-01-01

    Tai Chi (TC) is a slow-motion contemplative exercise that is associated with improvements in sensorimotor measures, including decreased force variability, enhanced tactile acuity, and improved proprioception, especially in elderly populations. Here, we carried out two studies evaluating the effect of TC practice on measures associated with sensorimotor processing. In study 1, we evaluated TC's effects on an oscillatory parameter associated with motor function, beta rhythm (15-30 Hz) coherence, focusing specifically on beta rhythm intermuscular coherence (IMC), which is tightly coupled to beta corticomuscular coherence (CMC). We utilized electromyography (EMG) to compare beta IMC in older TC practitioners with age-matched controls, as well as novices with advanced TC practitioners. Given previous findings of elevated, maladaptive beta coherence in older subjects, we hypothesized that increased TC practice would be associated with a monotonic decrease in beta IMC, but rather discovered that novice practitioners manifested higher beta IMC than both controls and advanced practitioners, forming an inverted U-shaped practice curve. This finding suggests that TC practice elicits complex changes in sensory and motor processes over the developmental lifespan of TC training. In study 2, we focused on somatosensory (e.g., tactile and proprioceptive) responses to the rubber hand illusion (RHI) in a middle-aged TC group, assessing whether responses to the illusion became dampened with greater cumulative practice. As hypothesized, TC practice was associated with decreased likelihood to misattribute tactile stimulation during the RHI to the rubber hand, although there was no effect of TC practice on measures of proprioception or on subjective reports of ownership. These studies provide preliminary evidence that TC practice both modulates beta network coherence in a non-linear fashion, perhaps as a result of the focus on not only efferent motor but also afferent sensory activity

  15. Effects of chronic metoprolol and sulphinpyrazone on human lymphocyte beta-adrenoceptors.

    OpenAIRE

    Blasi, A.; Cortellaro, M; Costantini, C.

    1984-01-01

    Multiple (100 mg twice daily for 21 days) but not single (100 mg) oral doses of metoprolol significantly reduced the number (Bmax) and the KD of beta-adrenoceptors on intact lymphocytes from nine healthy volunteers. Sulphinpyrazone (400 mg twice daily for 21 days) did not change lymphocyte beta-adrenoceptors and did not modify their reaction to chronic metoprolol. In vitro sulphinpyrazone (10-4M) increased [3H]-DHA specific binding on intact lymphocytes. This effect was not modified by metopr...

  16. Relativistic effects in gamma-ray bursts

    International Nuclear Information System (INIS)

    According to recent models of the sources of gamma-ray bursts the extremely energetic emission is caused by shells expanding with ultrarelativistic velocity. With the recent identification of optical sources at the positions of some gamma-ray bursts these ''fireball'' models have acquired an actuality that invites to use them as a motivating application when teaching special relativity. We demonstrate several relativistic effects associated with these models which are very pronounced due to the great velocity of the shell. For example a burst lasting for a month in the rest frame of an element of the shell lasts for a few seconds only, in the rest frame of our detector. It is shown how the observed properties of a burst are modified by aberration and the Doppler effect. The apparent luminosity as a function of time is calculated. Modifications due to the motion of the star away from the observer are calculated. (Author)

  17. Gamma-ray Constraints on Effective Interactions

    CERN Document Server

    Cheung, Kingman; Yuan, Tzu-Chiang

    2011-01-01

    Using an effective interaction approach to describe the interactions between the dark matter particle and the light degrees of freedom of the standard model, we calculate the gamma-ray flux due to the annihilation of the dark matter into quarks, followed by fragmentation into neutral pions which subsequently decay into photons. By comparison to the mid-latitude data released from the Fermi-LAT experiment, we obtain useful constraints on the size of the effective interactions and they are found to be comparable to those deduced from collider, gamma-ray line and anti-matter search experiments. However, the two operators induced by scalar and vector exchange among fermionic dark matter and light quarks that contribute to spin-independent cross sections are constrained more stringently by the recent XENON100 data.

  18. Recent trends in total reflection X-ray fluorescence spectrometry for biological applications

    International Nuclear Information System (INIS)

    This review is focused on the application of total reflection X-ray fluorescence (TXRF) spectrometry in the field of biological research. In the last decade, most papers were published by authors who applied laboratory-scale TXRF equipments. The application of synchrotron radiation as excitation source (SR-TXRF) shows a slowly increasing tendency. In the cited papers the micro-, trace and multielement capability of these TXRF techniques was demonstrated in the clinical and medical laboratory practice, as well as in various plant physiological studies. For speciation of elements in biological matrices, the TXRF was used as element specific detector following an off-line separation step (e.g., thin layer chromatography, high performance liquid chromatography), however, these off-line methods are not competitive with the on-line coupled HPLC-inductively coupled plasma mass spectrometry

  19. Heteroaryl Chalcones: Design, Synthesis, X-ray Crystal Structures and Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2013-10-01

    Full Text Available Chalcone derivatives have attracted increasing attention due to their numerous pharmacological activities. Changes in their structures have displayed high degree of diversity that has proven to result in a broad spectrum of biological activities. The present study highlights the synthesis of some halogen substituted chalcones 3(a–i containing the 5-chlorothiophene moiety, their X-ray crystal structures and the evaluation of possible biological activities such as antibacterial, antifungal and reducing power abilities. The results indicate the tested compounds show a varied range of inhibition values against all the tested microbial strains. Compound 3c with a p-fluoro substituent on the phenyl ring exhibits elevated antimicrobial activity, whereas the compounds 3e and 3f displayed the least antimicrobial activities. The compounds 3d, 3e, 3f and 3i showed good ferric and cupric reducing abilities, and the compounds 3b and 3c showed the weakest reducing power in the series.

  20. Heteroaryl chalcones: design, synthesis, X-ray crystal structures and biological evaluation.

    Science.gov (United States)

    Kumar, C S Chidan; Loh, Wan-Sin; Ooi, Chin Wei; Quah, Ching Kheng; Fun, Hoong-Kun

    2013-01-01

    Chalcone derivatives have attracted increasing attention due to their numerous pharmacological activities. Changes in their structures have displayed high degree of diversity that has proven to result in a broad spectrum of biological activities. The present study highlights the synthesis of some halogen substituted chalcones 3(a-i) containing the 5-chlorothiophene moiety, their X-ray crystal structures and the evaluation of possible biological activities such as antibacterial, antifungal and reducing power abilities. The results indicate the tested compounds show a varied range of inhibition values against all the tested microbial strains. Compound 3c with a p-fluoro substituent on the phenyl ring exhibits elevated antimicrobial activity, whereas the compounds 3e and 3f displayed the least antimicrobial activities. The compounds 3d, 3e, 3f and 3i showed good ferric and cupric reducing abilities, and the compounds 3b and 3c showed the weakest reducing power in the series. PMID:24132195

  1. Resistance of Xanthomonas maltophilia to antibiotics and the effect of beta-lactamase inhibitors.

    Science.gov (United States)

    Neu, H C; Saha, G; Chin, N X

    1989-01-01

    We examined the susceptibility of 50 isolates of Xanthomonas maltophilia and the effect of beta-lactamase inhibitors upon the susceptibility. The majority of isolates were resistant to azlocillin, piperacillin, mezlocillin, ticarcillin, cefotaxime, ceftizoxime, ceftriaxone, cefoperazone, and ceftazidime. All isolates were resistant to imipenem, CGP 31608, aztreonam, and carumonam. Although disk susceptibility tests showed that the combination of clavulanate with ticarcillin inhibited many isolates, at a ratio of 1:20 few isolates were susceptible to the combination. Addition of clavulanate to aztreonam and to imipenem failed to make organisms susceptible. Sulbactam combined with cefoperazone made some organisms susceptible, but ampicillin-sulbactam was ineffective, whereas tazobactam combined with piperacillin at a ratio of 1:4 made half the isolates have MICs of 32 micrograms/ml or less. The beta-lactamases from the isolates hydrolyzed all of the beta-lactams. PMID:2791491

  2. Recent advances in particle-induced X-ray emission analysis applied to biological samples

    International Nuclear Information System (INIS)

    Papers reporting the application of particle induced X-ray emission (PIXE) analysis to biological samples continue to appear regularly in the literature. The majority of these papers deal with blood, hair, and other common body organs while a few deal with biological samples from the environnment. A variety of sample preparation methods have been demonstrated, a number of which are improvements, refinements and extensions of the thick- and thin-sample preparation methods reported in the early development of PIXE. While many papers describe the development of PIXE techniques some papers are now describing applications of the methods to serious biological problems. The following two factors may help to stimulate more consistant use of the PIXE method. First, each PIXE facility should be organized to give rapid sample processing and should have available several sample preparation and handling methods. Second, those with the skill to use PIXE methods need to become closely associated with researches knowledge able in medical and biological sciences and they also need to become more involved in project planning and sample handling. (orig.)

  3. Barbiturate bearing aroylhydrazine derivatives: Synthesis, NMR investigations, single crystal X-ray studies and biological activity

    Science.gov (United States)

    Giziroglu, Emrah; Sarikurkcu, Cengiz; Aygün, Muhittin; Basbulbul, Gamze; Soyleyici, H. Can; Firinci, Erkan; Kirkan, Bulent; Alkis, Ayse; Saylica, Tayfur; Biyik, Halil

    2016-03-01

    A series of barbituric acid aroylhydrazine derivatives have been prepared from their corresponding 1,3-dimethyl-5-acetyl barbituric acid and aroylhydrazines. All compounds have been fully characterized by using FT-IR, multinuclear NMR (1H, 13C) and Mass (MS) spectrometry. We also describe the X-ray crystal structure of 3a, which crystallizes in the monoclinic P21/n space group. The crystal structure is stabilized with infinite linear chains of dimeric units. Furthermore, all compounds were investigated for their tyrosinase inhibition, antioxidative and antimicrobial activies. The results from biological activity assays have shown that all of compounds have excellent antioxidant, significant tyrosinase inhibition and moderate antimicrobial activity.

  4. Effects of meal size and composition on incretin, alpha-cell, and beta-cell responses

    DEFF Research Database (Denmark)

    Rijkelijkhuizen, Josina M; McQuarrie, Kelly; Girman, Cynthia J;

    2009-01-01

    The incretins glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) regulate postprandial insulin release from the beta-cells. We investigated the effects of 3 standardized meals with different caloric and nutritional content in terms of postprandial glucose, insu...

  5. Development of an effective delayed neutron fraction calculation code, BETA-K

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taek Kyum; Song, Hoon; Kim, Young Il; Kim, Young In; Kim, Young Jin [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-08-01

    BETA-K, an effective delayed neutron fraction calculation code consistent with Nodal Expansion Method (NEM), has been developed. By using relevant output files of DIF3D code, it can calculate the effective delayed neutron fraction({beta}{sub eff}), neutron lifetime(l{sub eff}), fission spectrum ({chi}-bar) and fission yield data({nu}) for each fissionable isotope, composition of fuels and over the whole core. BETA-K code has been validated by comparing the calculated values to the measured ones of effective delayed neutron fraction in two critical experiments, BFS73-1 and BFS55-1. BFS73-1 is a metal uranium core and BFS55-1 is a metal plutonium core. The C/E values, 1.007 and 0.992 for BFS73-1 and BFS55-1 respectively, agreed well with the experimental values within the experiment errors. BETA-K code predicts 0.00709 and 0.356 {mu}sec as the effective delayed neutron fraction and neutron life time for the uranium metallic fueled equilibrium core of 150MWe KALIMER. (author). 9 refs., 6 figs., 12 tabs.

  6. 75 FR 4877 - In the Matter of Beta Gamma Nuclear Radiology; Confirmatory Order Modifying License (Effective...

    Science.gov (United States)

    2010-01-29

    ... rule (72 FR 49139, August 28, 2007). The E-Filing process requires participants to submit and serve all... Gamma Nuclear Radiology; Confirmatory Order Modifying License (Effective Immediately) I Beta Gamma Nuclear Radiology (BGNR) (Licensee) is the holder of medical License No. 52-25542-01, issued by the...

  7. Effect of the gamma radiation of cobalt 60 on the beta carotids present in the carrot

    International Nuclear Information System (INIS)

    In the present work it was investigated the effect of the gamma radiation of cobalt 60 on the beta carotid's in the carrot (daucus carota), using for it three different radiation dose (100, 150 and 200 kilo-rad) and analyzing them by means of the liquid chromatography technique of high resolution (HPLC)

  8. Effects of putrescine, cadaverine, spermine, spermidine and beta-phenylethylamine on cultured bovine mammary epithelial cells

    DEFF Research Database (Denmark)

    Fusi, Eleonora; Baldi, Antonella; Cheli, Federica;

    2008-01-01

    A bovine mammary epithelial cell line (BME-UV1) and three-dimensional collagen primary bovine organoids were used to evaluate the effects of cadaverine, putrescine, spermine, spermicline and beta-phenylethylamine on mammary epithelial cells. Each biogenic amine was diluted in several concentratio...

  9. Expression and characterization of recombinant single-chain salmon class I MHC fused with beta2-microglobulin with biological activity

    DEFF Research Database (Denmark)

    Zhao, Heng; Stet, René J M; Skjødt, Karsten;

    2008-01-01

    Heterodimeric class I major histocompatibility complex (MHC) molecules consist of a putative 45-kDa heavy chain and a 12-kDa beta2-microglobulin (beta2m) light chain. The knowledge about MHC genes in Atlantic salmon accumulated during the last decade has allowed us to generate soluble and stable ...... molecules by biosensor analysis. This production of sufficient amounts of class I MHC proteins may represent a useful tool to study the peptide-binding specificity of MHC class I molecules, in order to design a peptide vaccine against viral pathogens....... resistance to infectious salmon anaemia virus. The single-chain salmon MHC class I molecule has been designed and generated, in which the carboxyl terminus of beta2m is joined together with a flexible 15 or 20 amino acid peptide linker to the amino terminus of the heavy chain (Sasabeta2mUBA*0301). Monoclonal...

  10. Effect of Doping on beta-Tricalcium Phosphate Bioresorbable Bulk Material and Thin Film Coatings

    Science.gov (United States)

    Abdalla, Suhaila

    Magnesium has emerged as a revolutionary biodegradable metal for use as an orthopedic material, it has several advantages over the current metallic materials in use, including eliminating the effects of stress shielding, improving biocompatibility and inhibiting degradation rates, thus removing the requirement of a second surgery for implant removal. Due to the rapid degradation of magnesium, it is necessary to control the corrosion rates of the materials to match the rates of bone healing. This dissertation reports on the effect of doping on the properties of beta-tricalcium phosphate (beta-TCP). It also reports on its application as a thin film coating on magnesium alloys for implant applications. Adding various dopants to beta-TCP significantly influences critical properties. In this study, discs were fabricated in two compositions: (i) undoped beta-TCP, (ii) beta-TCP doped with 1.0 wt % MgO, 0.5 wt % ZnO, and 1.0 wt % TiO2. Films were fabricated from these compositions using the pulsed laser deposition (PLD) technique. These coatings were then characterized for corrosive, hardness, and cytocompatibility. The XRD patterns of the coating confirm the amorphous nature of the films. The presence of the metal oxides in beta-TCP improved ceramic densification. The application of these doped coatings was also found to increase the hardness by 88 %, the modulus of elasticity by 66 %, and improve corrosion resistance of the magnesium alloy substrate; with a 2.4 % improvement in Ecorr and 95 % decrease in icorr. Cell viability was studied using an osteoblast precursor cell line MC3T3-E1 to assure that the biocompatibility of these ceramics was not altered due to the dopants. Long-term biodegradation studies were conducted by measuring weight change and surface microstructure as a function of time in simulated body fluid. The results suggest that these coatings could be used for bioresorbable implants with improved corrosion resistance and increased hardness.

  11. The effects of beta acids from hops (Humulus lupulus L.)on mortality of Varroa destructor (Acari: Varroidae)

    Science.gov (United States)

    Beta acids from hop plants (Humulus lupulus L.) reduce feeding and oviposition behaviors and increase mortality in certain phytophagous mites. These compounds were tested for their effects on Varroa destructor (Anderson and Trueman) mortality. The effects of hops beta acids (HBA) on honey bee (Apis ...

  12. Biological responses of brushite-forming Zn- and ZnSr- substituted beta-tricalcium phosphate bone cements

    Directory of Open Access Journals (Sweden)

    S Pina

    2010-09-01

    Full Text Available The core aim of this study was to investigate zinc (Zn- and zinc and strontium (ZnSr-containing brushite-forming beta-tricalcium phosphate (TCP cements for their effects on proliferation and differentiation of osteoblastic-like cells (MC3T3-E1 cell line as well as for their in vivo behaviour in trabecular bone cylindrical defects in a pilot study. In vitro proliferation and maturation responses of MC3T3-E1 osteoblastic-like cells to bone cements were studied at the cellular and molecular levels. The Zn- and Sr-containing brushite cements were found to stimulate pre-osteoblastic proliferation and osteoblastic maturation. Indeed, MC3T3-E1 cells exposed to the powdered cements had increased proliferative rates and higher adhesiveness capacity, in comparison to control cells. Furthermore, they exhibited higher alkaline phosphatase (ALP activity and increased Type-I collagen secretion and fibre deposition into the extracellular matrix. Proliferative and collagen deposition properties were more evident for cells grown in cements doped with Sr. The in vivo osteoconductive propertiesof the ZnCPC and ZnSrCPC cements were also pursued. Histological and histomorphometric analyses were performed at 1 and 2 months after implantation, using carbonated apatite cement (Norian SRS® as control. There was no evidence of cement-induced adverse foreign body reactions, and furthermore ZnCPC and ZnSrCPC cements revealed better in vivo performance in comparison to the control apatite cement. Additionally, the presence of both zinc and strontium resulted in the highest rate of new bone formation. These novel results indicate that the investigated ZnCPC and ZnSrCPC cements are both biocompatible and osteoconductive, being good candidate materials to use as bone substitutes.

  13. SIX2 Effects on Wilms Tumor Biology

    Directory of Open Access Journals (Sweden)

    Janene Pierce

    2014-12-01

    Full Text Available Wilms tumor (WT blastema retains gene expression profiles characteristic of the multipotent nephron progenitor pool, or cap mesenchyme (CM, in the developing kidney. As a result, WT blastema and the CM are believed to represent contextual analogues of one another. Sine oculis homeobox 2 (SIX2 is a transcription factor expressed specifically in the CM, provides a critical mechanism for CM self-renewal, and remains persistently active in WT blastema, although its purpose in this childhood malignancy remains unclear. We hypothesized that SIX2, analogous to its function in development, confers a survival pathway to blastema, the putative WT stem cell. To test its functional significance in WT biology, wild-type SIX2 was overexpressed in the human WT cell line, WiT49. After validating this model, SIX2 effects on anchorage-independent growth, proliferation, invasiveness, canonical WNT pathway signaling, and gene expression of specific WNT pathway participants were evaluated. Relative to controls, WiT49 cells overexpressing SIX2 showed significantly enhanced anchorage-independent growth and early-passage proliferation representing surrogates of cell survival. Interestingly, overexpression of SIX2 generally repressed TCF/LEF-dependent canonical WNT signaling, which activates and coordinates both differentiation and stem pathways, but significantly heightened canonical WNT signaling through the survivin promoter, a mechanism that exclusively maintains the stem state. In summary, when overexpressed in a human WT cell line, SIX2 enhances cell survival and appears to shift the balance in WNT/β-catenin signaling away from a differentiation path and toward a stem cell survival path.

  14. Effect of isoniazid, a haem inhibitor, on globin chain synthesis in reticulocytes from non-thalassaemic and beta thalassaemic subjects.

    OpenAIRE

    Chalevelakis, G; Yalouris, A G; Lyberatos, C; Economopoulos, T; Anastasiou, C.; Hatziioannou, J; Raptis, S

    1989-01-01

    The effect of isonicotinic acid hydrazide (INH), a potent haem inhibitor, on globin chain synthesis was studied in reticulocytes from the following groups of patients: four non-thalassaemic patients (group i); five beta thalassaemia heterozygotes (group ii); three Hb S/beta thalassaemia heterozygotes (group iii); and two additional patients--one with homozygous beta thalassaemia and the other with thalassaemia intermedia (group iv). This was done to determine whether haem inhibitors depress a...

  15. Effect of kappa-casein and beta-lactoglobulin loci on milk production traits and reproductive performance of Holstein cows

    OpenAIRE

    Tsiaras, AM; Bargouli, GG; Banos, G.; Boscos, CM

    2005-01-01

    The effects of kappa-casein (kappa-CN) and beta-lactoglobulin (beta-LG) loci on milk production traits (milk, fat, protein, and lactose yield, fat, protein, and lactose content) and reproductive performance (gestation length, calving interval, age at first and second calving, number of services per conception) was estimated for 278 Holstein cows in the first 2 lactations. Genotypes of kappa-CN and beta-LG were determined by alkaline and acidic polyacrylamide gel electrophoresis. Milk producti...

  16. Effects of prenatal exposure to low dose beta radiation from tritiated water on postnatal growth and neurobehavior of mice

    International Nuclear Information System (INIS)

    Pregnant adult C57BL/6J mice were randomly assigned to 4 groups and 3 of them were irradiated with beta-rays from tritiated water (HTO) by a single intraperitoneal injection on the 12.5 th day of gestation. Their offsprings received cumulative dose of 0.036, 0.071 and 0.213 Gy, respectively. Offspring of mice were observed for postnatal growth (body weight), the appearance of four physiologic makers (eye opening, pinna detachment, testes decent, vaginal opening), the age of acquisition of two reflexes (cloff avoidance, air righting) and sensuous functions (auditory startle, pain threshold), movement and coordination functions and activity (pivoting, foot splay, continuous corridor activity), and learning and memory (electric avoidance reflex in Y-maze, conditioning reflex). It was found that results for the parameters in 0.036 or 0.071 Gy group were differed significantly from those for the controls, and for most parameters, a dose dependent effect was found

  17. Effects of internal and external hydrogen on mechanical properties of beta III titanium alloy sheet

    International Nuclear Information System (INIS)

    Results of investigation of Ti-base--Mo--Zr--Sn (Beta III alloy), Ti-base--Mo--Cr--Al (VT-15 alloy), and Ti-base-V-Cr-Al (Beta I alloy) show that in the β condition, Beta III is less susceptible to hydrogen elongation (HE) than the other β alloys Beta I and VT 15, similarly H-charged during solution treatment (ST). Not only He, but also H softening can occur in the alloy H charged during various heat treatments. The α-stabilizing effects of cold working (CW) and of previously absorbed O compete with the high temperature β-stabilization by H, decrease H softening and favor HE. The influence of stress state on H effects and the need for sensitive enough tests are again evidenced. A new criterion is proposed to select materials to be stressed in an H environment. H dragging by dislocations plays an important role in HE. This points out the influence of strain rate testing. Furthermore it becomes critically important when environmental degradation depends on film rupture and repassivation. The disk pressure tests are more sensitive than tensile tests and present the adequate sensitivity and versatility to meet the requirements of the complex H effects situation in Ti alloys. With a single set up, using only one specimen geometry, tests can be run at rates ranging from low to high, then the inhomogeneous biaxial stresses involved make them to approach the kind of data usually supplied by impact tests

  18. Biological effects of low-dose ionizing radiation exposure

    International Nuclear Information System (INIS)

    The report on the meeting of the Strahlenschutzkommission 2007 concerning biological effects of low-dose ionizing radiation exposure includes the following contributions: Adaptive response. The importance of DNA damage mechanisms for the biological efficiency of low-energy photons. Radiation effects in mammography: the relative biological radiation effects of low-energy photons. Radiation-induced cataracts. Carcinomas following prenatal radiation exposure. Intercellular apoptosis induction and low-dose irradiation: possible consequences for the oncogenesis control. Mechanistic models for the carcinogenesis with radiation-induced cell inactivation: application to all solid tumors in the Japanese atomic bomb survivors. Microarrays at low radiation doses. Mouse models for the analysis of biological effects of low-dose ionizing radiation. The bystander effect: observations, mechanisms and implications. Lung carcinoma risk of Majak workers - modeling of carcinogenesis and the bystander effect. Microbeam studies in radiation biology - an overview. Carcinogenesis models with radiation-induced genomic instability. Application to two epidemiological cohorts.

  19. Effects of beta-blockers on heart failure with preserved ejection fraction: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Feng Liu

    Full Text Available BACKGROUND: Effects of beta-blockers on the prognosis of the heart failure patients with preserved ejection fraction (HFpEF remain controversial. The aim of this meta-analysis was to determine the impact of beta-blockers on mortality and hospitalization in the patients with HFpEF. METHODS: A search of MEDLINE, EMBASE, and the Cochrane Library databases from 2005 to June 2013 was conducted. Clinical studies reporting outcomes of mortality and/or hospitalization for patients with HFpEF (EF ≥ 40%, being assigned to beta-blockers treatment and non-beta-blockers control group were included. RESULTS: A total of 12 clinical studies (2 randomized controlled trials and 10 observational studies involving 21,206 HFpEF patients were included for this meta-analysis. The pooled analysis demonstrated that beta-blocker exposure was associated with a 9% reduction in relative risk for all-cause mortality in patients with HFpEF (95% CI: 0.87 - 0.95; P < 0.001. Whereas, the all-cause hospitalization, HF hospitalization and composite outcomes (mortality and hospitalization were not affected by this treatment (P=0.26, P=0.97, and P=0.88 respectively. CONCLUSIONS: The beta-blockers treatment for the patients with HFpEF was associated with a lower risk of all-cause mortality, but not with a lower risk of hospitalization. These finding were mainly obtained from observational studies, and further investigations are needed to make an assertion.

  20. X-ray Absorption Spectroscopy and Coherent X-ray Diffraction Imaging for Time-Resolved Investigation of the Biological Complexes: Computer Modelling towards the XFEL Experiment

    Science.gov (United States)

    Bugaev, A. L.; Guda, A. A.; Yefanov, O. M.; Lorenz, U.; Soldatov, A. V.; Vartanyants, I. A.

    2016-05-01

    The development of the next generation synchrotron radiation sources - free electron lasers - is approaching to become an effective tool for the time-resolved experiments aimed to solve actual problems in various fields such as chemistry’ biology’ medicine’ etc. In order to demonstrate’ how these experiments may be performed for the real systems to obtain information at the atomic and macromolecular levels’ we have performed a molecular dynamics computer simulation combined with quantum chemistry calculations for the human phosphoglycerate kinase enzyme with Mg containing substrate. The simulated structures were used to calculate coherent X-ray diffraction patterns’ reflecting the conformational state of the enzyme, and Mg K-edge X-ray absorption spectra, which depend on the local structure of the substrate. These two techniques give complementary information making such an approach highly effective for time-resolved investigation of various biological complexes, such as metalloproteins or enzymes with metal-containing substrate, to obtain information about both metal-containing active site or substrate and the atomic structure of each conformation.

  1. Synthesis and biological activity of beta-glucuronyl carbamate-based prodrugs of paclitaxel as potential candidates for ADEPT

    NARCIS (Netherlands)

    deBont, DBA; Leenders, RGG; Haisma, HJ; vanderMeulenMuileman, [No Value; Scheeren, HW

    1997-01-01

    The syntheses of prodrugs of paclitaxel, which can be used in ADEPT in order to target paclitaxel towards tumor cells, are described. The prodrugs 1 and 2a,b consist of a spacer molecule connected via a carbamate linkage to a beta-glucuronic acid. The spacer molecule is also connected via an ester l

  2. Three-dimensional visualisation of soft biological structures by X-ray computed micro-tomography.

    Science.gov (United States)

    Shearer, Tom; Bradley, Robert S; Hidalgo-Bastida, L Araida; Sherratt, Michael J; Cartmell, Sarah H

    2016-07-01

    Whereas the two-dimensional (2D) visualisation of biological samples is routine, three-dimensional (3D) imaging remains a time-consuming and relatively specialised pursuit. Current commonly adopted techniques for characterising the 3D structure of non-calcified tissues and biomaterials include optical and electron microscopy of serial sections and sectioned block faces, and the visualisation of intact samples by confocal microscopy or electron tomography. As an alternative to these approaches, X-ray computed micro-tomography (microCT) can both rapidly image the internal 3D structure of macroscopic volumes at sub-micron resolutions and visualise dynamic changes in living tissues at a microsecond scale. In this Commentary, we discuss the history and current capabilities of microCT. To that end, we present four case studies to illustrate the ability of microCT to visualise and quantify: (1) pressure-induced changes in the internal structure of unstained rat arteries, (2) the differential morphology of stained collagen fascicles in tendon and ligament, (3) the development of Vanessa cardui chrysalises, and (4) the distribution of cells within a tissue-engineering construct. Future developments in detector design and the use of synchrotron X-ray sources might enable real-time 3D imaging of dynamically remodelling biological samples. PMID:27278017

  3. The effect of noise on beta-cell burst period

    DEFF Research Database (Denmark)

    Pedersen, Morten Gram; Sørensen, Mads Peter

    2006-01-01

    on numerical simulations. We show here how the application of two recent methods allows an analytic treatment of the stochastic effects on the location of the saddle-node and homoclinic bifurcations, which determine the burst period. Thus, the stochastic system can be analyzed similarly to the...... isolated and coupled cells has been suggested to be due to stochastic fluctuations of the plasma membrane ions channels, which are supposed to have a stronger effect on single cells than on cells situated in clusters (the channel sharing hypothesis). This effect of noise has previously been studied based...

  4. A comparison of biological effect and spray liquid distribution and deposition for different spray application techniques in different crops

    OpenAIRE

    Larsolle, Anders; Wretblad, Per; Westberg, Carl

    2002-01-01

    The objective of this study was to compare a selection of spray application techniques with different application volumes, with respect to the spray liquid distribution on flat surfaces, the deposition in fully developed crops and the biological effect. The spray application techniques in this study were conventional spray technique with three different nozzles: Teelet XR, Lechler ID and Lurmark DriftBeta, and also AirTec, Danfoil, Hardi Twin, Kyndestoit and Släpduk. The dynamic spray liquid ...

  5. Biological effects of anthropogenic contaminants in the San Francisco Estuary

    Science.gov (United States)

    Thompson, B.; Adelsbach, T.; Brown, C.; Hunt, J.; Kuwabara, J.; Neale, J.; Ohlendorf, H.; Schwarzbach, S.; Spies, R.; Taberski, K.

    2007-01-01

    Concentrations of many anthropogenic contaminants in the San Francisco Estuary exist at levels that have been associated with biological effects elsewhere, so there is a potential for them to cause biological effects in the Estuary. The purpose of this paper is to summarize information about biological effects on the Estuary's plankton, benthos, fish, birds, and mammals, gathered since the early 1990s, focusing on key accomplishments. These studies have been conducted at all levels of biological organization (sub-cellular through communities), but have included only a small fraction of the organisms and contaminants of concern in the region. The studies summarized provide a body of evidence that some contaminants are causing biological impacts in some biological resources in the Estuary. However, no general patterns of effects were apparent in space and time, and no single contaminant was consistently related to effects among the biota considered. These conclusions reflect the difficulty in demonstrating biological effects due specifically to contamination because there is a wide range of sensitivity to contaminants among the Estuary's many organisms. Additionally, the spatial and temporal distribution of contamination in the Estuary is highly variable, and levels of contamination covary with other environmental factors, such as freshwater inflow or sediment-type. Federal and State regulatory agencies desire to develop biological criteria to protect the Estuary's biological resources. Future studies of biological effects in San Francisco Estuary should focus on the development of meaningful indicators of biological effects, and on key organism and contaminants of concern in long-term, multifaceted studies that include laboratory and field experiments to determine cause and effect to adequately inform management and regulatory decisions. ?? 2006 Elsevier Inc. All rights reserved.

  6. Differentiation of biological hydroxyapatite compounds by infrared spectroscopy, x-ray diffraction and extended x-ray absorption fine structure

    Science.gov (United States)

    Chassot, E.; Oudadesse, H.; Irigaray, J.; Curis, E.; Bénazeth, S.; Nicolis, I.

    2001-12-01

    Pure hydroxyapatite (HAP) and HAP doped with 800 ppm of zinc were implanted in cortical bone of femur diaphysis of ovines [J. L. Irigaray et al., Mater. Clin. Appl. 28, 399 (1999)]. We observed that the doped HAP was better resorbed than pure HAP. The first hypothesis is that zinc acts as a stimulator on macrophage cells and improves quantity and quality of osteoblast cells. The second hypothesis is that zinc yields HAP structure that is better resorbed in biological field. For our experiment we used HAP doped with 3000 ppm of zinc in order to have a good sensitivity. In the present work, chemical studies by inductively coupled plasma absorption emission spectrometry, x ray diffraction, and infrared were carried out to determine the composition of major and trace elements in the doped hydroxyapatite, and the crystallographic structure. These studies can indicate possible modifications induced by the insertion of zinc. We used the extended x-ray absorption fine structure experimental station of LURE (Orsay, France) to try to clarify the atomic surroundings of zinc in doped HAP structure and transformations induced in initial lattice. Despite the low zinc concentration, we got good quality fluorescence mode spectra. These spectra showed medium range order of the material that is consistent with its crystalline form. To perform the analysis, we compared the result obtained with another models like β tricalcium phosphate and we created theoretical models of zinc in substitution of calcium in order to reproduce as well as possible the experimental spectrum. After this study, only two models are coherent with experimental spectrum, zinc in substitution of calcium in site I and zinc in the interstice between the two hydroxydes.

  7. Studying of ion implantation effect on the biology in China

    International Nuclear Information System (INIS)

    Since low energy ion effect on the biology was observed, the ion implantation as a new mutagenic source has been widely used in improving crops and modifying microbes in China. The basic phenomenon of ion implantation effect on the biology and analytical results are reported, and the examples of its application and its further development are shown

  8. Ion irradiation and the biological effect of immune system

    International Nuclear Information System (INIS)

    Ion irradiation exists broadly in the people's life. It can induce a series of the biological effect in body depending on the different type and dose of ionization. This article expound the effect of ion irradiation on the biological function of immune system, affording the theorial guide in the appreciation, precaution and treatment of irradiation injury. (authors)

  9. Effects of Beta-Decays of Excited-State Nuclei on the Astrophysical r-Process

    CERN Document Server

    Famiano, M A; Kajino, T; Otsuki, K; Terasawa, M; Mathews, G J

    2008-01-01

    A rudimentary calculation is employed to evaluate the possible effects of beta- decays of excited-state nuclei on the astrophysical r-process. Single-particle levels calculated with the FRDM are adapted to the calculation of beta-decay rates of these excited-state nuclei. Quantum numbers are determined based on proximity to Nilson model levels. The resulting rates are used in an r-process network calculation in which a supernova hot-bubble model is coupled to an extensive network calculation including all nuclei between the valley of stability and the neutron drip line and with masses A<284. Beta-decay rates are included as functional forms of the environmental temperature. While the decay rate model used is simple and phenomenological, it is consistent across all 3700 nuclei involved in the r-process network calculation. This represents an approximate first estimate to gauge the possible effects of excited-state beta-decays on r-process freeze-out abundances.

  10. Technology Rich Biology Labs: Effects of Misconceptions.

    Science.gov (United States)

    Kuech, Robert; Zogg, Gregory; Zeeman, Stephan; Johnson, Mark

    This paper describes a study conducted on the lab sections of the general biology course for non-science majors at the University of New England, and reports findings of student misconceptions about photosynthesis and the mass/carbon uptake during plant growth. The current study placed high technology analytic tools in the hands of introductory…

  11. Effects of feeding Beta vulgaris saccharifera bulb for fattening desert lambs under tropical conditions of Sudan

    OpenAIRE

    M D Mohammed; K.M. ELAMIN; A E Amin; H E Hassan; A F Khalid

    2012-01-01

    Aim: The objective of this study was to evaluate the effects of introducing Sugar Beet bulb as a cheap substitute for grains in rations formulated for sheep fattening. Materials and Methods: This trial was conducted at the Experimental unit of Rural Development and extension center, Faculty of animal production, University of Gezira. Twenty four Sudanese desert lambs (Ashgur ecotype) were purchased from local markets to assess the effects of replacing grain with Sugar Beet (Beta vulgaris sacc...

  12. The modifying effect of beta-carotene on radiation and chemotherapy induced oral mucositis

    International Nuclear Information System (INIS)

    The purpose of this study of 20 patients with advanced squamous carcinoma of the mouth was to monitor the dose modifying effect of supplemental dietary beta-carotene on the progression of the oral mucosal reaction and treatment outcome during an intensive course of synchronous radiation and chemotherapy. Tumour response and long term normal tissue changes have been carefully recorded. Results and freedom from toxic side effects suggest further studies. (author)

  13. X-ray tomography: Biological cells in 3-D at better than 50 nm resolution

    International Nuclear Information System (INIS)

    Full text: X-ray microscopy can be used to image whole, hydrated, specimens with a spatial resolution 5-10 times better than that obtained using visible light microscopy. X-ray imaging at photon energies below the K- absorption edge of oxygen, referred to as the water window, exploits the strong natural contrast for organic material embedded in a mostly water matrix. With a transmission X-ray microscope using Fresnel zone plate optics, specimens up to 10 microns thick can be examined. The highest X-ray transmission in hydrated samples is obtained at a wavelength of 2.4 nm but, due to the low numerical aperture of zone plate lenses operated in st order diffraction mode the structures resolved are much larger than the X-ray wavelength. Because of the low NA of X-ray lenses (NA=0.05), combined with the effect of polychromatic illumination and a wavelength dependant focal length, the effective depth of ld is large (6-10 microns). The experiments presented here were performed at the Advanced Light Source using the full ld transmission X-ray microscope, XM-1. This microscope employs a bend magnet X-ray source and zone plate condenser and objective lenses. The condenser zone plate acts as a monochromator and the X-ray images are recorded directly on a cooled, back-thinned 1024x1024 pixel CCD camera. The sample holder was a rotationally symmetric glass tube; the region containing the sample was 10 microns in diameter with a wall thickness of 200 nm. Live yeast cells were loaded into the tube, rapidly frozen by a blast of liquid nitrogen-cooled helium gas, and maintained at 140 deg C by a steady flow of cold helium. The image sequence spanned 180 deg and consisted of 45 images spaced by 4 deg. The images were aligned to a common axis and computed tomographic reconstruction was used to obtain the 3-D X-ray linear absorption coefficient. Volume rendering and animation of reconstructed data was performed using the 3-D program, Amira. Acquisition time for 90 images was 3 min

  14. Efeito da suplementação de beta-caroteno na pressão arterial de ratos Effect of beta-carotene supplementation on the blood pressure of rats

    Directory of Open Access Journals (Sweden)

    Giselle Santos de Oliveira

    2007-02-01

    detect possible toxic effects or interaction between nutrients and analysis of biological parameters; systolic blood pressure was measured by plethysmography twice a week on alternate days; after the supplementation period, animals were killed and their livers weighed by the Scherle method. RESULTS: Administration of beta-carotene did not alter the animals' biological parameters or cause any toxic effects. Regarding systolic blood pressure, both lineages showed significant results (p<0.05, with the highest dose presenting the best results. The average liver weight was 7.25 (3.2 standard-deviation grams, and the relationship between the average liver weight and body weight was 0.0192 for the hypertensive group. CONCLUSION: Beta-carotene supplementation was effective in controlling and preventing hypertension in rats. The relationship between liver weight and body weight was normal.

  15. Experimental studies of high-energy X-ray emission and bootstrap current generation in high [epsilon][beta][sub p] lower-hybrid driven plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Squire, J.P.; Porkolab, M.; Colborn, J.A.; Villasenor, J. (Plasma Fusion Center and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States))

    1994-10-15

    High poloidal beta ([epsilon][beta][sub p]-1) plasma equilibria have been produced by injection of lower-hybrid waves with both asymmetric (current-drive) and symmetric (heating) spectra in the Versator II tokamak. Asymmetric and symmetric injection both generate nearly the same plasma current (5kA), with the loop voltage measured as zero. We studied the rf-created high energy electron distribution with a radial and tangential array of X-ray spectrometers (1[double prime][times]3[double prime] NaI), along with a single soft X-ray spectrometer (SiLi). Analysis of the X-ray data is carried out using a bremsstrahlung emission code. We find that nearly all of the plasma current in the current-drive case can be accounted for by the asymmetric electron tail. In the heating case, the soft X-ray data indicates the presence of an enhanced population of intermediate energy electrons ([similar to]10 keV) consistent with that of the launched LH wave spectrum. Our estimates show that bootstrap current generated by these electrons can account for a majority of the plasma current.

  16. A system for simultaneous beta and gamma spectroscopy

    Science.gov (United States)

    Farsoni, A. T.; Hamby, D. M.

    2007-08-01

    A state-of-the-art radiation detection system for real-time and simultaneous spectroscopy of beta-particles and gamma-rays has been developed. The system utilizes a triple-layer phoswich detector and a customized Digital Pulse Processor (DPP) designed and built in our laboratory. The DPP board digitally captures the analog signal pulses and, following several digital preprocessing steps, transfers valid pulses to the host computer for further digital processing. A resolving algorithm also was developed to digitally discriminate beta and gamma events, and reconstruct separate beta and gamma-ray energy spectra with minimal crosstalk. The spectrometer has proven to be an effective tool for recording separate beta and gamma-ray spectra from mixed radiation fields. The system as a beta-gamma spectrometer will have broad-ranging applications in nuclear non-proliferation, radioactive waste management, worker safety, systems reliability, dose assessment, and risk analysis.

  17. Knowledge Gaps in Rodent Pancreas Biology: Taking Human Pluripotent Stem Cell-Derived Pancreatic Beta Cells into Our Own Hands

    OpenAIRE

    Santosa, Munirah Mohamad; Low, Blaise Su Jun; Pek, Nicole Min Qian; Teo, Adrian Kee Keong

    2016-01-01

    In the field of stem cell biology and diabetes, we and others seek to derive mature and functional human pancreatic β cells for disease modeling and cell replacement therapy. Traditionally, knowledge gathered from rodents is extended to human pancreas developmental biology research involving human pluripotent stem cells (hPSCs). While much has been learnt from rodent pancreas biology in the early steps toward Pdx1+ pancreatic progenitors, much less is known about the transition toward Ngn3+ p...

  18. Finite beta effects on turbulent transport in tokamak plasmas

    International Nuclear Information System (INIS)

    The research on the transport properties of magnetically confined plasmas plays an essential role towards the achievement of practical nuclear fusion energy. An economically viable fusion reactor is expected to operate at high plasma pressure. This implies that the detailed study of the impact of electromagnetic effects, whose strength increases with increasing pressure, is of critical importance. In the present work, the electromagnetic effects on the particle, momentum and heat transport channels have been investigated, with both analytical and numerical calculations. Transport processes due to a finite plasma pressure have been identified, their physical mechanisms have been explained, and their contributions have been quantified, showing that they can be significant under experimentally relevant conditions.

  19. Effective Majorana mass and neutrinoless double beta decay

    Energy Technology Data Exchange (ETDEWEB)

    Benato, Giovanni, E-mail: gbenato@physik.uzh.ch [Physik Institut der Universität Zürich, Zurich (Switzerland)

    2015-11-28

    The probability distribution for the effective Majorana mass as a function of the lightest neutrino mass in the standard three neutrino scheme is computed via a random sampling from the distributions of the involved mixing angles and squared mass differences. A flat distribution in the [0,2π] range for the Majorana phases is assumed, and the dependence of small values of the effective mass on the Majorana phases is highlighted. The study is then extended with the addition of the cosmological bound on the sum of the neutrino masses. Finally, the prospects for 0νββ decay search with {sup 76}Ge, {sup 130}Te and {sup 136}Xe are discussed, as well as those for the measurement of the electron neutrino mass.

  20. [Bases of the antibacterial effect of beta lactam antibiotics].

    Science.gov (United States)

    Hof, H

    1991-12-01

    The primary antibacterial effect of betalactam antibiotics is due to the inhibition of cell-wall synthesis. Prerequisites for good antibacterial activity of such an antibiotic are --rapid penetration across the bacterial cell wall, --strong binding to the proper targets in the cytoplasmic membrane, i.e. the penicillin-binding proteins, --resistance to betalactamases which may be produced by the bacterial cell. PMID:1802833

  1. PGC-1alpha and PGC-1beta have both similar and distinct effects on myofiber switching toward an oxidative phenotype

    DEFF Research Database (Denmark)

    Mortensen, Ole Hartvig; Frandsen, Lis; Schjerling, Peter; Nishimura, Erica; Grunnet, Niels

    2006-01-01

    Peroxisome proliferator-activated receptor-gamma coactivator-1alpha and -1beta (PGC-1alpha and PGC-1beta) were overexpressed by adenovirus-mediated gene transfer in cultures of primary rat skeletal muscle cells derived from neonatal myoblasts. Effects on muscle fiber type transition and metabolism...

  2. Negative effect of 17-beta-estradiol on growth parameters of goldfish (Carassius auratus

    Directory of Open Access Journals (Sweden)

    Reza Tarkhani

    2015-03-01

    Full Text Available Objective: To evaluate the effects of 17-beta-estradiol on growth factors of goldfish (Carassius auratus. Methods: To perform the test, 17-beta-estradiol was given 3 months period to fish at different doses as followed: control group, Group 1: 10 mg/kg food, Group 2: 25 mg/kg food and Group 3: 50 mg/kg food. For this purpose, a solution of hormone in pure ethanol used to spray on food. Feeding was done 3 times daily as an appetite. Comparing the mean values measured for length and weight using ANOVA. Results: Indicated with increase length and weight, the effects of the hormone get more distinct, so that with increase concentration of hormone, reduce weight and length. Conclusions: Estradiol along with testosterone and progesterone regulates final stages of oocyte maturation and ovulation. Various studies have proven the different concentrations of this hormone has different effects on the growth of different fishes.

  3. Hypoglycemic and beta cell protective effects of andrographolide analogue for diabetes treatment

    Directory of Open Access Journals (Sweden)

    Larrick James W

    2009-07-01

    Full Text Available Abstract Background While all anti-diabetic agents can decrease blood glucose level directly or indirectly, few are able to protect and preserve both pancreatic beta cell mass and their insulin-secreting functions. Thus, there is an urgent need to find an agent or combination of agents that can lower blood glucose and preserve pancreatic beta cells at the same time. Herein, we report a dual-functional andrographolide-lipoic acid conjugate (AL-1. The anti-diabetic and beta cell protective activities of this novel andrographolide-lipoic acid conjugate were investigated. Methods In alloxan-treated mice (a model of type 1 diabetes, drugs were administered orally once daily for 6 days post-alloxan treatment. Fasting blood glucose and serum insulin were determined. Pathologic and immunohistochemical analysis of pancreatic islets were performed. Translocation of glucose transporter subtype 4 in soleus muscle was detected by western blot. In RIN-m cells in vitro, the effect of AL-1 on H2O2-induced damage and reactive oxidative species production stimulated by high glucose and glibenclamide were measured. Inhibition of nuclear factor kappa B (NF-κB activation induced by IL-1β and IFN-γ was investigated. Results In alloxan-induced diabetic mouse model, AL-1 lowered blood glucose, increased insulin and prevented loss of beta cells and their dysfunction, stimulated glucose transport protein subtype 4 (GLUT4 membrane translocation in soleus muscles. Pretreatment of RIN-m cells with AL-1 prevented H2O2-induced cellular damage, quenched glucose and glibenclamide-stimulated reactive oxidative species production, and inhibited cytokine-stimulated NF-κB activation. Conclusion We have demonstrated that AL-1 had both hypoglycemic and beta cell protective effects which translated into antioxidant and NF-κB inhibitory activity. AL-1 is a potential new anti-diabetic agent.

  4. Dual aminergic regulation of central beta adrenoceptors. Effect of atypical antidepressants and 5-hydroxytryptophan

    International Nuclear Information System (INIS)

    Nonlinear regression analysis of agonist competition binding curves reveals that the [3H]-dihydroalprenolol-labeled receptor population with low affinity for isoproterenol is increased by p-chlorophenylalanine (PCPA) and this increase is abolished by 5-hydroxytryptophan (5-HTP) in vivo. Desipramine (DMI) decreased the beta adrenoceptor population with high agonist affinity to the same degree in PCPA-treated animals as in control animals, thus explaining the reported discrepancy between beta adrenoceptor number and responsiveness of the beta adrenoceptor-coupled adenylate cyclase system. Mianserin also selectively reduced the beta adrenoceptor population with high agonist affinity in membrane preparations of normal animals, whereas fluoxetine selectively abolished the upregulation of the low affinity sites in reserpinized animals and had no effect on either receptor population from brain of normal animals. The results emphasize the importance of nonlinear regression analysis of agonist competition binding for the interpretation of drug action and encourage the pursuit of the molecular neurobiology of the serotonin (5-HT)/norepinephrine (NE) link in brain

  5. Effect of beta-aescin extract from Chinese buckeye seed on chronic venous insufficiency.

    Science.gov (United States)

    Yu, Zhihong; Su, Ping

    2013-06-01

    The aim of this study was to explore the mechanism of domestic beta-aescin treating chronic venous insufficiency through observing its actions on the isolated canine saphenous venous tension, venous pressure, venous return and lymphatic return. The isolated canine spiral saphenous venous tension test was performed to detect the activity of the beta-aescin. Furthermore, in the condition of constant canine femoral artery perfusion kept in the extracorporeal circulation, we measured the changes of the canine femoral artery pressure, femoral artery flow and the lymphatic return flow after intravenous injection of the agent. The results showed that when beta-aescin was administrated at the dose between 5.0 x 10(-5)-5.25 x 10(-4) mol/L, it increased obviously the contractile tension of the venous to norepinephrine in a dose-dependent manner. With canine femoral artery perfusion kept constant, beta-aescin, whose doses were 50 mg and 100 mg, reinforced intently the canine femoral venous tension accelerated the rise of the venous pressure. These finding suggested that domestic betabeta-aescin extracted from Chinese Buckeye Seed had an effect on chronic venous insufficiency by strengthening the venous tension, increasing the venous pressure and promoting venous return and lymphatic return. PMID:23875249

  6. Effectiveness of interferon-beta and temozolomide combination therapy against temozolomide-refractory recurrent anaplastic astrocytoma

    Directory of Open Access Journals (Sweden)

    Arai Hajime

    2007-08-01

    Full Text Available Abstract Background Malignant gliomas recur even after extensive surgery and chemo-radiotherapy. Although a relatively novel chemotherapeutic agent, temozolomide (TMZ, has demonstrated promising activity against recurrent glioma, the effects last only a few months and drug resistance develops thereafter in most cases. Induction of O6-methylguanine-DNA methyltransferase (MGMT in tumors is considered to be responsible for resistance to TMZ. Interferon-beta has been reported to suppress MGMT in an experimental glioma model. Here we report a patient with TMZ-refractory anaplastic astrocytoma (AA who was treated successfully with a combination of interferon-beta and TMZ. Case presentation A patient with recurrent AA after radiation-chemotherapy and stereotactic radiotherapy was treated with TMZ. After 6 cycles, the tumor became refractory to TMZ, and the patient was treated with interferon-beta at 3 × 106 international units/body, followed by 5 consecutive days of 200 mg/m2 TMZ in cycles of 28 days. After the second cycle the tumor decreased in size by 50% (PR. The tumor showed further shrinkage after 8 months and the patient's KPS improved from 70% to 100%. The immunohistochemical study of the initial tumor specimen confirmed positive MGMT protein expression. Conclusion It is considered that interferon-beta pre-administration increased the TMZ sensitivity of the glioma, which had been refractory to TMZ monotherapy.

  7. Analysis of the surface technology of silicon detectors for imaging of low-energy beta tracers in biological material

    CERN Document Server

    Tykva, R

    2000-01-01

    Using silicon surface barrier detectors, the counting sensitivity of low-energy beta tracers is considerably influenced by surface technology applied in detector manufacturing. Original diagnostic procedure, using a mixture of uranium fission products, is described to trace the behaviors of different admixtures as in the etching bath as in the water used during development of the detector surface. In combination with some other described analyses, the detectors produced with the developed surface control are used in a PC - controlled scanning equipment reaching at room temperature an FWHM of 3.4 keV for sup 2 sup 4 sup 1 Am. Such detectors make it possible to image distribution, of e.g., sup 3 H, sup 1 sup 2 sup 5 I, sup 3 H+ sup 1 sup 4 C and other beta tracer combinations applied in life and environmental sciences.

  8. Aspartate beta-decarboxylase from Alcaligenes faecalis: carbon-13 kinetic isotope effect and deuterium exchange experiments

    International Nuclear Information System (INIS)

    The authors have measured the 13C kinetic isotope effect at pH 4.0, 5.0, 6.0, and 6.5 and in D2O at pH 5.0 and the rate of D-H exchange of the alpha and beta protons of aspartic acid in D2O at pH 5.0 for the reaction catalyzed by the enzyme aspartate beta-decarboxylase from Alcaligenes faecalis. The 13C kinetic isotope effect, with a value of 1.0099 +/- 0.0002 at pH 5.0, is less than the intrinsic isotope effect for the decarboxylation step, indicating that the decarboxylation step is not entirely rate limiting. The authors have been able to estimate probable values of the relative free energies of the transition states of the enzymatic reaction up to and including the decarboxylation step from the 13C kinetic isotope effect and the rate of D-H exchange of alpha-H. The pH dependence of the kinetic isotope effect reflects the pKa of the pyridine nitrogen of the coenzyme pyridoxal 5'-phosphate but not that of the imine nitrogen. A mechanism is proposed for the exchange of aspartate beta-H that is consistent with the stereochemistry suggested earlier

  9. Aspartate beta-decarboxylase from Alcaligenes faecalis: carbon-13 kinetic isotope effect and deuterium exchange experiments

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, R.M.; O' Leary, M.H.

    1985-03-26

    The authors have measured the /sup 13/C kinetic isotope effect at pH 4.0, 5.0, 6.0, and 6.5 and in D/sub 2/O at pH 5.0 and the rate of D-H exchange of the alpha and beta protons of aspartic acid in D/sub 2/O at pH 5.0 for the reaction catalyzed by the enzyme aspartate beta-decarboxylase from Alcaligenes faecalis. The /sup 13/C kinetic isotope effect, with a value of 1.0099 +/- 0.0002 at pH 5.0, is less than the intrinsic isotope effect for the decarboxylation step, indicating that the decarboxylation step is not entirely rate limiting. The authors have been able to estimate probable values of the relative free energies of the transition states of the enzymatic reaction up to and including the decarboxylation step from the /sup 13/C kinetic isotope effect and the rate of D-H exchange of alpha-H. The pH dependence of the kinetic isotope effect reflects the pKa of the pyridine nitrogen of the coenzyme pyridoxal 5'-phosphate but not that of the imine nitrogen. A mechanism is proposed for the exchange of aspartate beta-H that is consistent with the stereochemistry suggested earlier.

  10. Calibration of photon and beta ray sources used in brachytherapy. Guidelines on standardized procedures at Secondary Standards Dosimetry Laboratories

    International Nuclear Information System (INIS)

    cardiovascular interventions. The present report includes a description of suitable detector systems that can be used for the calibration. It must be emphasized that for safe use of brachytherapy a comprehensive quality assurance (QA) programme should be developed at the radiotherapy center using this modality. A QA programme cannot rest on a source calibration alone, but in addition it should address all the different steps included in the treatment process. Such a programme is described in IAEA- TECDOC-1040, 'Design and Implementation of a Radiotherapy Programme: Clinical, Medical Physics, Radiation Protection and Safety Aspects'. As summarized in the present report, omission of a QA programme may have serious consequences for a patient undergoing brachytherapy treatment. The parts of this publication describing the calibration of low energy photon sources and beta ray sources have been written in close collaboration with members of the International Commission on Radiation Units and Measurements (ICRU)

  11. Modeling the effects of repeated systemic administrations of small activity amounts In radionuclide therapy with beta emitters

    International Nuclear Information System (INIS)

    Full text: Good results for radionuclide therapy treatments where repeated short time spaced systemic injection of small activity amounts are given have been reported. Bone marrow and kidneys are usually considered as dose-limiting organs in radionuclide therapy. The treatments in radionuclide therapy with repeated administration could be optimized if irradiation effects in those one might be estimated. Xeno-grafted mice is the often biological model used during the evaluation of candidates for radionuclide therapy. A mathematical model of tumor cell kinetics was combined with another one reported for marrow cell kinetics which allows the calculation of marrow cell survival and proliferation in response to different irradiation schemes. Radionuclide therapy treatment with repeated administrations with radiopharmaceuticals labeled with beta emitters were simulated. The effects on fast-growing and slow-growing tumors were evaluated, as well as radiosensitive and radioresistant tumors. For more realistic estimation of absorbed dose in mice organs the cross-irradiation due to high energy beta particles was included into the MIRD's formula. Tumor and kidneys responses to the irradiation were estimated on the linear-quadratic model framework which was adapted for a multi-exponential dose rate function describing radionuclide therapy treatments with repeated administrations. Published values for murine tumors kinetics, marrows cellular turnover rates and radiosensitivities were used during the calculations. Iso-effective schemes were also determined varying the interval between fractions and the number of administration. For a given tolerated level of thrombocytopenia and absorbed dose in kidneys an optimal regime of radionuclide therapy with repeated administration could be found. The mathematical model presented here allows the prediction of the nadir and duration of thrombocytopenia, the effects on kidneys and the tumor cell response to various treatment schemes

  12. Comparative Neuroregenerative Effects of C-Phycocyanin and IFN-Beta in a Model of Multiple Sclerosis in Mice.

    Science.gov (United States)

    Pentón-Rol, Giselle; Lagumersindez-Denis, Nielsen; Muzio, Luca; Bergami, Alessandra; Furlan, Roberto; Fernández-Massó, Julio R; Nazabal-Galvez, Marcelo; Llópiz-Arzuaga, Alexey; Herrera-Rolo, Tania; Veliz-Rodriguez, Tania; Polentarutti, Nadia; Marín-Prida, Javier; Raíces-Cruz, Ivette; Valenzuela-Silva, Carmen; Teixeira, Mauro Martins; Pentón-Arias, Eduardo

    2016-03-01

    Multiple Sclerosis (MS) therapies approved so far are unable to effectively reverse the chronic phase of the disease or improve the remyelination process. Here our aim is to evaluate the effects of C-Phycocyanin (C-Pc), a biliprotein from Spirulina platensis with anti-oxidant, anti-inflammatory and cytoprotective properties, in a chronic model of experimental autoimmune encephalomyelitis (EAE) in mice. C-Pc (2, 4 or 8 mg/kg i.p.) or IFN-beta (2000 IU, s.c.) was administered daily once a day or every other day, respectively, starting at disease onset, which differ among EAE mice between 11 and 15 days postinduction. Histological and immunohistochemistry (anti-Mac-3, anti-CD3 and anti-APP) assessments were performed in spinal cord in the postinduction time. Global gene expression in the brain was analyzed with the Illumina Mouse WG-6_V2 BeadChip microarray and the expression of particular genes, assessed by qPCR using the Fast SYBR Green RT-PCR Master Mix. Oxidative stress parameters (malondialdehyde, peroxidation potential, CAT/SOD ratio and GSH) were determined spectrophoto-metrically. Results showed that C-Pc ameliorates the clinical deterioration of animals, an effect that expresses the reduction of the inflammatory infiltrates invading the spinal cord tissue, the axonal preservation and the down-regulation of IL-17 expression in brain tissue and serum. C-Pc and IFN-beta improved the redox status in mice subjected to EAE, while microarray analysis showed that both treatments shared a common subset of differentially expressed genes, although they also differentially modulated another subset of genes. Specifically, C-Pc mainly modulated the expression of genes related to remyelination, gliogenesis and axon-glia processes. Taken together, our results indicate that C-Pc has significant therapeutic effects against EAE, mediated by the dynamic regulation of multiple biological processes. PMID:26556034

  13. Effects of applied pressure on hot-pressing of Beta-SiC

    Science.gov (United States)

    Kinoshita, M.; Matsumura, H.; Iwasa, M.; Hayami, R.

    1984-01-01

    The effects of applied pressure on the densification during hot pressing of beta-SiC compacts were investigated. Beta-SiC powder is Starck made and has the average particle size of about 0.7 micrometer. Hot pressing experiments were carried out in graphite dies at temperatures of 1700 deg to 2300 deg C and at the pressures up to 1000 kg/sq cm. The compacts containing 1 weight percent B4C were examined. Sintered compacts were examined for microstructure and the Rockwell A-scale hardness was measured. The B4C addition was very effective to mitigate the hot pressing conditions. It is found that densification goes with the strengthening of the bonding and does not occur in particle deformation due to concentrated stress.

  14. Evolutionary Tradeoffs between Economy and Effectiveness in Biological Homeostasis Systems

    OpenAIRE

    Pablo Szekely; Hila Sheftel; Avi Mayo; Uri Alon

    2013-01-01

    Biological regulatory systems face a fundamental tradeoff: they must be effective but at the same time also economical. For example, regulatory systems that are designed to repair damage must be effective in reducing damage, but economical in not making too many repair proteins because making excessive proteins carries a fitness cost to the cell, called protein burden. In order to see how biological systems compromise between the two tasks of effectiveness and economy, we applied an approach ...

  15. Non-Thermal Effects Mobile Phones at Biological Objects

    OpenAIRE

    Ladislav Balogh

    2003-01-01

    The article deals with non-thermal effects of mobile phones on biological objects. Even though these effects are observed for longer period, there are not so far unequivocal results on obtained biological and biophysical results in this field. Biologicaleffects of electromagnetic field (EMF) depend on its character, its duration as well as on features of organism. As the receptors offield are not known (e.g. inputs of EMF into organism), its effects are judged only by non-specific reaction of...

  16. Biological effectiveness of neutron irradiation on animals and man

    Energy Technology Data Exchange (ETDEWEB)

    Straume, T.

    1982-11-01

    Neutron experiments on a highly radiosensitive in vivo system - oocytes in mice - provide new insight into the nature of the radiosensitive targets of these important cells. With the radiobiological literature as background, neutron data from animals and humans are integrated, and the controversial question of radiation protection standards for neutrons is addressed. Oocyte killing in juvenile mice by 0.43-MeV, /sup 252/Cf-fission, and 15 MeV neutrons, compared with that by /sup 60/Co gamma rays, yields unusually low neutron RBEs (relative biological effectiveness). At 0.1 rad of 0.43-MeV neutrons the RBE is only 1.8, contrasting greatly with values of 100 or more reported at low-doses for other endpoints. In mice just prior to birth, however, when oocytes are less radiosensitive, the neutron RBE is much higher, similar to values for most other mammalian endpoints. This dramatic change in neutron RBE with mouse age (occurring within 2 to 3 days) can be explained as the result of a shift from a less radiosensitive target (presumably nuclear DNA) to a much more radiosensitive one (probably the oocyte plasma membrane). Using various approaches, a value for the neutron Quality Factor (Q, a radiation protection standard) is estimated as 17 (+-100%), much lower than 100 which has been suggested. With the large uncertainty, 17 is not markedly different from the value of 10 presently in general use.

  17. Biological effectiveness of neutron irradiation on animals and man

    International Nuclear Information System (INIS)

    Neutron experiments on a highly radiosensitive in vivo system - oocytes in mice - provide new insight into the nature of the radiosensitive targets of these important cells. With the radiobiological literature as background, neutron data from animals and humans are integrated, and the controversial question of radiation protection standards for neutrons is addressed. Oocyte killing in juvenile mice by 0.43-MeV, 252Cf-fission, and 15 MeV neutrons, compared with that by 60Co gamma rays, yields unusually low neutron RBEs (relative biological effectiveness). At 0.1 rad of 0.43-MeV neutrons the RBE is only 1.8, contrasting greatly with values of 100 or more reported at low-doses for other endpoints. In mice just prior to birth, however, when oocytes are less radiosensitive, the neutron RBE is much higher, similar to values for most other mammalian endpoints. This dramatic change in neutron RBE with mouse age (occurring within 2 to 3 days) can be explained as the result of a shift from a less radiosensitive target (presumably nuclear DNA) to a much more radiosensitive one (probably the oocyte plasma membrane). Using various approaches, a value for the neutron Quality Factor (Q, a radiation protection standard) is estimated as 17 (+-100%), much lower than 100 which has been suggested. With the large uncertainty, 17 is not markedly different from the value of 10 presently in general use

  18. Overexpression of estrogen receptor beta alleviates the toxic effects of beta-amyloid protein on PC12 cells via non-hormonal ligands

    Institute of Scientific and Technical Information of China (English)

    Hui Wang; Lihui Si; Xiaoxi Li; Weiguo Deng; Haimiao Yang; Yuyan Yang; Yan Fu

    2012-01-01

    After binding to the estrogen receptor, estrogen can alleviate the toxic effects of beta-amyloid protein, and thereby exert a therapeutic effect on Alzheimer's disease patients. Estrogen can increase the incidence of breast carcinoma and endometrial cancer in post-menopausal women, so it is not suitable for clinical treatment of Alzheimer's disease. There is recent evidence that the estrogen receptor can exert its neuroprotective effects without estrogen dependence. Real-time quantitative PCR and flow cytometry results showed that, compared with non-transfected PC12 cells, adenovirus-mediated estrogen receptor β gene-transfected PC12 cells exhibited lower expression of tumor necrosis factor α and interleukin 1β under stimulation with beta-amyloid protein and stronger protection from apoptosis. The Akt-specific inhibitor Abi-2 decreased the anti-inflammatory and anti-apoptotic effects of estrogen receptor β gene-transfection. These findings suggest that overexpression of estrogen receptor β can alleviate the toxic effect of beta-amyloid protein on PC12 cells, without estrogen dependence. The Akt pathway is one of the potential means for the anti-inflammatory and anti-apoptotic effects of the estrogen receptor.

  19. Effect of Gamma-Ray Beaming on the Fluxes of Gamma-Ray Pulsars

    Institute of Scientific and Technical Information of China (English)

    JIANG Ze-Jun; ZHANG Li

    2005-01-01

    @@ We study the effect ofγ-ray beaming on γ-ray emission of the pulsars in a self-sustained outer gap model. In this model, averaged γ-ray flux is a function of period, magnetic field, magnetic inclination angle and solid angle of γ-ray beaming for a γ-ray pulsar. We generate a sample of γ-ray pulsars with their ages less than 106 years by using the Monte Carlo method, and then study the γ-ray beaming effect. The comparison of distributions of periods, magnetic fields, distances, γ-ray energy fluxes and period derivatives of the simulated γ-ray pulsars with those of observed γ-ray pulsars by the detector EGRET shows that γ-ray beaming has an important role on the detection ofγ-ray pulsars. Furthermore, possible γ-ray pulsars observed by the detector GLAST are predicted.PACS: 97. 60. Gb, 95. 85. Pw, 97. 10. Yp

  20. Effect of pregnancy on differentiation of minor Beta-Thalassemia from iron deficiency

    OpenAIRE

    Ghanei M

    1997-01-01

    Differential diagnosis of Iron-deficiency anemia and Beta-Thalassemia, two common causes of anemia, affects the treatment in pregnant women. To help the diagnosis, we have tried to asses the pure effect of gestation on diagnostic criteria, eliminating iron and folate deficiency. In a prospective study, 46 thalassemic women were given Ferrous Sulphate tablets and Folate. Some indices, CBC and HbA2 were measured before and after treatment during pregnancy. The haemoglobin and HbA2 decreased and...

  1. Thermal ion effects on kinetic beta-induced Alfven eigenmodes excited by energetic ions

    Energy Technology Data Exchange (ETDEWEB)

    Qi Longyu; Sheng, Z. M. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Dong, J. Q. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Southwestern Institute of Physics, Chengdu 610041 (China); Bierwage, A. [Aomori Research and Development Center, Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Lu Gaimin [Southwestern Institute of Physics, Chengdu 610041 (China)

    2013-03-15

    Kinetic beta-induced Alfven eigenmodes (KBAEs) driven by energetic ions are numerically investigated using revised AWECS code. The thermal ion density and temperature gradients are taken into account. It is found that the growth rate of the KBAEs increases with the thermal ion pressure gradient, and the contributions from the density gradient and temperature gradient of the thermal ions to the enhancement of the instability are comparable. The damping effect of thermal ion dynamics on the modes is also observed.

  2. Effect of beta-glucan in preventing bacterial translocation in a model of experimental obstructive jaundice

    OpenAIRE

    Polat, Fatin Rüştü; Dinelek, Hasan

    2012-01-01

    Abstract Aim. Sepsis is the major cause of post-operative morbidity and mortality in obstructive jaundice as a result of bacterial translocation from the gut. This study was conducted to investigate the effect of beta-glucan in preventing bacterial translocation in an animal model where obstructive jaundice was developed by common bile duct ligation. Methods. Forty-five Wistar-albino rats were divided into three groups of fifteen animal each. Only laparotomy was administered to the first grou...

  3. Synthesis and biological evaluation of phenolic 4,5-dihydroisoxazoles and 3-hydroxy ketones as estrogen receptor alpha and beta agonists.

    Science.gov (United States)

    Poutiainen, Pekka K; Venäläinen, Tuomas A; Peräkylä, Mikael; Matilainen, Juha M; Väisänen, Sami; Honkakoski, Paavo; Laatikainen, Reino; Pulkkinen, Juha T

    2010-05-15

    In this work, 52 diphenyl-4,5-dihydroisoxazoles and -3-hydroxy ketones were prepared and their estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta) activities were explored in order to systematize and maximize their biological activity. The biological activity was firstly screened by using ERE reporter assay to find out how aromatic hydroxylation and methylation of the chiral centers of the compounds affect the ability of ER to mediate biological responses. For selected 19 compounds, the relative binding affinities (RBA, relative to 3,17beta-estradiol) and ability to induce transcription of primary E2 target gene pS2 in human MCF-7 breast cancer cells were determined. In the reporter assay, many compounds showed even stronger activity than E2 and some of them showed RBA larger than 1%. The highest RBAs were determined for the enantiomers of 1-hydroxy-6-(4-hydroxy-phenyl)-1-phenyl-hexan-3-one (50a and 50b). Isomer 50a showed high binding affinity both to ERalpha (with RBA approximately 200%) and ERbeta (with RBA approximately 60%), while the RBAs of 50b were ca. 40% of those. Some of the other compounds (with RBA approximately 1-16%) showed also notable ERalpha binding selectivity. When four most promising ligands (50a, 50b, 45a, and 45b) were studied with respect to their ability to induce the transcription of primary E2 target gene pS2, the compounds acted as agonists or partial agonists. Computer modeling was used to predict receptor binding conformations and to rationalize the RBA differences of the compounds. PMID:20430632

  4. Biological effects: asbestos-cement manufacturing.

    Science.gov (United States)

    Weill, H

    1994-08-01

    Fourteen cohorts of asbestos-cement workers have been studied. These studies have demonstrated exposure-response relationships for lung cancer, mesothelioma and asbestosis. For lung cancer, relatively consistent results have been observed, with risk two-fold or less in 13 of the 14 cohorts. Among New Orleans workers, excess risk was restricted to those with X-ray evidence of asbestosis. Workers employed at least 21 years but without X-ray abnormalities, experienced no elevated risk, while those with small opacities (1/0 or higher) had substantially elevated risk (SMR > 400). Exposures in these two groups had been similar. These results suggest that asbestosis may be a necessary precursor for asbestos-induced lung cancer; if so, then the no-threshold model for lung cancer risk is inappropriate since there is general agreement that very low exposures will not result in radiologically detectable lung fibrosis. Further data on this potential link are needed. As in other industries, mesothelioma risk was strongly related to amphibole exposure, especially to crocidolite in asbestos-cement pipe manufacture. A cluster of cases has recently been reported in a family amosite-cement business. Among New Orleans workers, risk of asbestosis was related to cumulative exposure but there was little evidence of risk below 30 f ml-1-years. Progression of asbestosis in these workers was slow, related to past cumulative exposure and not related to lung function decline. Asbestosis risk is therefore not likely to develop in workers under current controlled exposure conditions. PMID:7978975

  5. Rapid effects of phytoestrogens on human colonic smooth muscle are mediated by oestrogen receptor beta.

    LENUS (Irish Health Repository)

    Hogan, A M

    2012-02-01

    Epidemiological studies have correlated consumption of dietary phytoestrogens with beneficial effects on colon, breast and prostate cancers. Genomic and non-genomic mechanisms are responsible for anti-carcinogenic effects but, until now, the effect on human colon was assumed to be passive and remote. No direct effect on human colonic smooth muscle has previously been described. Institutional research board approval was granted. Histologically normal colon was obtained from the proximal resection margin of colorectal carcinoma specimens. Circular smooth muscle strips were microdissected and suspended under 1g of tension in organ baths containing oxygenated Krebs solution at 37 degrees C. After an equilibration period, tissues were exposed to diarylpropionitrile (DPN) (ER beta agonist) and 1,3,5-tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole (PPT) (ER alpha agonist) or to the synthetic phytoestrogen compounds genistein (n=8), daidzein (n=8), fisetin (n=8) and quercetin (n=8) in the presence or absence of fulvestrant (oestrogen receptor antagonist). Mechanism of action was investigated by inhibition of downstream pathways. The cholinergic agonist carbachol was used to induce contractile activity. Tension was recorded isometrically. Phytoestrogens inhibit carbachol-induced colonic contractility. In keeping with a non-genomic, rapid onset direct action, the effect was within minutes, reversible and similar to previously described actions of 17 beta oestradiol. No effect was seen in the presence of fulvestrant indicating receptor modulation. While the DPN exerted inhibitory effects, PPT did not. The effect appears to be reliant on a p38\\/mitogen activated protein kinase mediated induction of nitric oxide production in colonic smooth muscle. The present data set provides the first description of a direct effect of genistein, daidzein, fisetin and quercetin on human colonic smooth muscle. The presence of ER in colonic smooth muscle has been functionally proven and the beta

  6. Topical Day on Biological Effects of Radiation

    International Nuclear Information System (INIS)

    The topical day has been focussed on the potential effects of ionizing radiation on human health. A general overview on molecular and biophysical aspects of radiation, its effects on cells and organisms, and the contribution of radiobiology to radiation protection and risk assessment is given. The genetic effects of radiation and its effects on the developing organism, the effects of radiation on the cell cycle and the mechanisms of radiation induced apoptosis were also discussed

  7. Topical Day on Biological Effects of Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Baatout, S.; Jacquet, P.

    1997-05-15

    The topical day has been focussed on the potential effects of ionizing radiation on human health. A general overview on molecular and biophysical aspects of radiation, its effects on cells and organisms, and the contribution of radiobiology to radiation protection and risk assessment is given. The genetic effects of radiation and its effects on the developing organism, the effects of radiation on the cell cycle and the mechanisms of radiation induced apoptosis were also discussed.

  8. Biological implications of high-energy cosmic ray induced muon flux in the extragalactic shock model

    CERN Document Server

    Atri, Dimitra

    2011-01-01

    A ~ 62 My periodicity in fossil biodiversity has been observed in independent studies of paleobiology databases going back 542 My. The period and phase of this biodiversity cycle coincides with the motion of our solar system in the galactic disk that oscillates perpendicular to the galactic plane with an amplitude of about 70 parsecs and a period of 63.6 My. Our Galaxy is falling toward the Virgo cluster due to its gravitational pull, forming a galactic shock at the north end of our galaxy due to this motion, capable of accelerating particles and exposing our galaxy's northern side to a higher flux of cosmic rays. These high-energy particles strike the Earth's atmosphere initiating extensive air showers, ionizing the atmosphere by producing charged secondary particles. Secondary particles such as muons produced as a result of nuclear interactions are able to reach the ground, enhancing the biological radiation dose, causing DNA damage and increasing mutation rates, which can have serious biological implicatio...

  9. Synchrotron-based X-ray fluorescence, imaging and elemental mapping from biological samples

    Indian Academy of Sciences (India)

    D V Rao; M Swapna; R Cesareo; A Brunetti; T Akatsuka; T Yuasa; T Takeda; G E Gigante

    2011-02-01

    The present study utilized the new hard X-ray microspectroscopy beamline facility, X27A, available at NSLS, BNL, USA, for elemental mapping. This facility provided the primary beam in a small spot of the order of ∼ 10 m, for focussing. With this spatial resolution and high flux throughput, the synchrotron-based X-ray fluorescent intensities for Mn, Fe, Zn, Cr, Ti and Cu were measured using a liquid-nitrogen-cooled 13-element energy-dispersive high-purity germanium detector. The sample is scanned in a `step-and-repeat’ mode for fast elemental mapping measurements and generated elemental maps at 8, 10 and 12 keV, from a small animal shell (snail). The accumulated trace elements, from these biological samples, in small areas have been identified. Analysis of the small areas will be better suited to establish the physiology of metals in specific structures like small animal shell and the distribution of other elements.

  10. Effective local control of malignant melanoma by intratumoural injection of a beta-emitting radionuclide

    International Nuclear Information System (INIS)

    In this study, therapeutic effect, morphological alterations and biological responses to the high-dose continuous irradiation delivered using this new technique were evaluated in an animal model with B16 melanoma. For evaluation of the therapeutic effect, 92 C57BL/6 mice with B16 melanoma were divided into four groups. In each group, intratumoural injections were performed when the tumour measured approximately 1 cm along its long axis. Group 1 (n=25) received 0.3 ml of normal saline, group 2 (n=15) 37 MBq of carrier-free holmium-166 in 0.3 ml saline, group 3 (n=27) 185 MBq of 166Ho in 0.3 ml saline and group 4 (n=25) 185 MBq of 166Ho in 0.5 ml saline. In addition, another 30 mice were used for morphological and biological analysis of the radiation effect. These 30 mice were injected with 185 MBq of 166Ho in 0.3 ml saline, and five were sacrificed at each of the following six time points: before injection and 1, 2, 3, 6 and 14 days post injection. For visual side-by-side comparison, melanoma cells were inoculated bilaterally into the back of ten additional mice, and 185 MBq of 166Ho in 0.3 ml of saline or an equal volume of normal saline was injected separately into the bilateral tumours. Nine days after inoculation of melanoma cells, mean tumour volume reached 492.5-631.9 mm3. Tumours of the control group (group 1) showed rapid growth, and the mean tumour volume reached approximately 30 times the original volume. None of the control group lived for more than 16 days following the injection of normal saline. On the other hand, mean tumour volume of the treated groups showed a gradual decrease, and 67%-74% of the treated animals were alive when all the control animals had died. The median survival of the control group was 9 days following injection, whereas it was 29 days in group 2, 33 days in group 3 and 33 days in group 4. The survival rate of group 3 was higher than that of groups 2 and 4, but statistical significance was not observed. H and E stain of the

  11. Biology of Myliobatis goodei (Springer, 1939), a widely distributed eagle ray, caught in northern Patagonia

    Science.gov (United States)

    Molina, Juan Manuel; Lopez Cazorla, Andrea

    2015-01-01

    Chondrichthyans play an important role in structuring marine communities. Myliobatis goodie is an eagle ray reported from South Carolina in the USA (35°N) to Santa Cuz, Argentina (44°S), however little is known about this species, which is considered data deficient by the IUCN. In order to create adequate management strategies for this species, biological information is sorely needed. The objective of this study was to describe the biology of the population of M. goodei and its relationships with season, sex and the geographic features of Anegada Bay, Argentina (from 39.96°S to 40.60°S and from 62.10°W to 62.46°W) in 2008. Specifically, the population structure of M. goodie was studied by sex, seasons and sites, its food habits by seasons and sites, and the reproductive biology by seasons and sex. The results show that M. goodei exhibits seasonal migrations. Young-of-the-year remain in the bay all year long, while adults enter during spring and summer. Juveniles in spring are likely to become first-time mating individuals that migrate into open sea at the end of summer. These individuals would return to give birth for the first time and mate for the second time during the next year at summer. Anegada Bay would then be a mating and nursery area for the species. M. goodei behave as a generalist feeder with a uniform diet composed mainly of bivalves. Seasonal differences in the diet found arise from differences in prey diversity between summer and spring. Spatial differences, however, arise from the different abundances of caprellids and bivalves. Trophic level was 3.2 and it constitutes the first reference for this species, characterizing it as a secondary consumer.

  12. Low energy photon mimic of the tritium beta decay energy spectrum

    Science.gov (United States)

    Malabre-O'Sullivan, Neville

    Tritium is a radioactive hydrogen isotope that is typically produced via neutron interaction with heavy water (D2O), producing tritiated water (DTO). As a result of this, tritium accounts for roughly a third of all occupational exposures at a CANDU type nuclear power plant. This identifies a need to study the biological effects associated with tritium (and low energy electrons in general). However, there are complications regarding the dosimetry of tritium, as well as difficulties in handling and using tritium for the purposes of biophysics experiments. To avoid these difficulties, an experiment has been proposed using photons to mimic the beta decay energy spectrum of tritium. This would allow simulation of the radiation properties of tritium, so that a surrogate photon source can be used for biophysics experiments. Through experimental and computational means, this work has explored the use of characteristic x-rays of various materials to modify the output spectrum of an x-ray source, such that it mimics the tritium beta decay spectrum. Additionally, the resultant primary electron spectrum generated in water from an x-ray source was simulated. The results from this research have indicated that the use of characteristic x-rays is not a viable method for simulating a tritium source. Also, the primary electron spectrum generated in water shows some promise for simulating tritium exposure, however further work must be done to investigate the slowing down electron spectrum. Keywords: Tritium, MCNP, low energy electrons, biophysics, characteristic x-rays.

  13. Cone-beam x-ray phase contrast tomography of biological samples; Optimization of contrast, resolution and field of view

    OpenAIRE

    Bartels, Matthias

    2013-01-01

    Three-dimensional information of entire objects can be obtained by the remarkable technique of computed tomography (CT). In combination with phase sensitive X-ray imaging high contrast for soft tissue structures can be achieved as opposed to CT based on classical radiography. In this work biological samples ranging from micrometer sized single cells over multi-cellular nerve tissue to entire millimeter sized organs are investigated by use of cone-beam propagationbased X-ray phase contrast. Op...

  14. SWEET CORN CULTIVAR INFLUENCES BIOLOGICALLY EFFECTIVE HERBICIDE DOSE [ABSTRACT

    Science.gov (United States)

    Competitive crop cultivars are considered a component of integrated weed management systems; however specific knowledge of interactions among crop cultivars and other management tactics, such as biologically effective herbicide dose, is limited. Observed variation in crop tolerance and weed supp...

  15. beta-adrenergic effects on carbohydrate metabolism in the unweighted rat soleus muscle

    Science.gov (United States)

    Kirby, Christopher R.; Tischler, Marc E.

    1990-01-01

    The effect of unweighting on the response of the soleus-muscle carbohydrate metabolism to a beta-adrenergic agonist (isoproterenol) was investigated in rats that were subjected to three days of tail-cast suspension. It was found that isoproterenol promoted glycogen degradation in soleus from suspended rats to a higher degree than in weighted soleus from control rats, and had no effect in unweighted digitorum longus. However, isoproterenol did not have a greater inhibitory effect on the net uptake of tritium-labeled 2-deoxy-glucose by the unweighted soleus and that isoproterenol inhibited hexose phosphorylation less in the unweighted than in the control muscle.

  16. Production and action of transforming growth factor-beta in human osteoblast cultures: dependence on cell differentiation and modulation by calcitriol

    DEFF Research Database (Denmark)

    Kassem, M; Kveiborg, Marie; Eriksen, E F

    2000-01-01

    Transforming growth factor beta (TGF-beta) plays an important role in skeletal remodelling. However, few studies have examined its effects on cultured human osteoblasts. Our aim is to characterise the biological effects of TGF-beta1 on human osteoblasts and to examine the interaction between TGF...

  17. The effect of interferon-beta on black holes in patients with multiple sclerosis.

    Science.gov (United States)

    Bagnato, Francesca; Evangelou, Iordanis E; Gallo, Antonio; Gaindh, Deeya; Yao, Karen

    2007-07-01

    Multiple sclerosis (MS) is an immunological disorder of the CNS. Linked to an initial transient inflammation as the result of blood-brain barrier leakage, the disease progresses into a neurodegenerative phase. MRI is the most powerful paraclinical tool for diagnosing and monitoring MS. Although contrast enhancing lesions are the visible events of blood-brain barrier breakdown, accumulation of hypointense lesions, namely black holes, are recognised as irreversible axonal loss. IFN-beta is administered as a first-line drug in MS patients. However, whether the effect of IFN-beta extends beyond just prevention of blood-brain barrier leakage and further prevents the formation of black holes or promotes their recovery once formed, is not yet understood. PMID:17665995

  18. The effect of suppressor of cytokine signaling 3 on GH signaling in beta-cells

    DEFF Research Database (Denmark)

    Rønn, Sif G; Hansen, Johnny A; Lindberg, Karen;

    2002-01-01

    . Furthermore, using Northern blot analysis it was shown that SOCS-3 can completely inhibit GH-induced insulin production in these cells. Finally, 5-bromodeoxyuridine incorporation followed by fluorescence-activated cell sorting analysis showed that SOCS-3 inhibits GH-induced proliferation of INS-1 cells. These......GH is an important regulator of cell growth and metabolism. In the pancreas, GH stimulates mitogenesis as well as insulin production in beta-cells. The cellular effects of GH are exerted mainly through activation of the Janus kinase-signal transducer and activator of transcription (STAT) pathway....... Recently it has been found that suppressors of cytokine signaling (SOCS) proteins are able to inhibit GH-induced signal transduction. In the present study, the role of SOCS-3 in GH signaling was investigated in the pancreatic beta-cell lines RIN-5AH and INS-1 by means of inducible expression systems. Via...

  19. QCD corrections to polarized Σ- beta decay: second class form factor effects

    International Nuclear Information System (INIS)

    Working within the framework of the MIT bag model, all six form factors describing the Σ- → n beta decay matrix element of the strangeness-changing weak current in the standard electroweak theory have been calculated, including QCD vertex corrections to order α/sub s/. The results are close to the predictions of the Cabibbo model, the QCD corrections not being very large. In particular, we found the induced second class weak electric dipole form factor to be small (g2 ≅ -0.04), in spite of the rather sizeable s - u quark mass difference, because it is significantly suppressed by quark confinement effects. Our results are in excellent agreement with the recent high statistics data on polarized Σ- beta decay, as are the Cabibbo model predictions. 10 refs

  20. Study of systematic effects in beta decay measurements with AgReO4 calorimeters

    CERN Document Server

    Monfardini, A; Cremonesi, O; Nucciotti, A; Sisti, M; Monfardini, Alessandro; Capozzi, Francesca; Cremonesi, Oliviero; Nucciotti, Angelo; Sisti, Monica

    2006-01-01

    AgReO4 microcalorimeters are planned to be used again in the next generation of calorimetric neutrino mass experiments with sensitivity down to 0.2 eV. The understanding and characterization of all possible sources of systematic uncertainties is crucial. In this work we focus on two of these sources, which have been studied in the 10 detectors of the Milano AgReO4 array experiment (MIBETA): a) the solid-state Beta Environmental Fine Structure (BEFS) observed for the first time in AgReO4; b) the detector energy response for internal beta events, which has been investigated with a dedicated measurement using a 44Ti gamma source. The possible effects on neutrino mass experiments due to the incomplete understanding of these two aspects are discussed.

  1. Effect of beta and collisionality on the vacuum magnetic field islands in stellarators

    International Nuclear Information System (INIS)

    We have used the resistive pressure gradient driven instability model to study the effect of plasma on a vacuum magnetic field island. We have studied under what conditions the island is amplified or reduced. Starting with a set of reference parameters, we have varied these parameters by increasing either the density or the electron temperature. These scans lead to very different results. When beta increase because of the increase in density so does the island width. However, in the case that beta is increase by increasing the electron temperature, we observe a decrease in the island width. The main mechanism for island reduction seems to be the generation of strong sheared flow associated with the magnetic island. These results seem to reflect some observations in the LHD device. (author)

  2. The microarray expression analysis identifies BAX as a mediator of beta-carotene effects on apoptosis.

    Science.gov (United States)

    Bodzioch, Marek; Dembinska-Kiec, Aldona; Hartwich, Jadwiga; Lapicka-Bodzioch, Katarzyna; Banas, Agnieszka; Polus, Anna; Grzybowska, Joanna; Wybranska, Iwona; Dulinska, Joanna; Gil, Dorota; Laidler, Piotr; Placha, Wojciech; Zawada, Magdalena; Balana-Nowak, Agnieszka; Sacha, Tomasz; Kiec-Wilk, Beata; Skotnicki, Aleksander; Moehle, Christoph; Langmann, Thomas; Schmitz, Gerd

    2005-01-01

    Beta-carotene is a ubiquitous compound rich in foods. However, there are conflicting reports regarding its role in carcinogenesis. We performed a microarray expression analysis in normal [human umbilical vein endothelial cells (HUVECs)] and neoplastic (melanoma A375 and myelomonocytic leukemia U937) actively proliferating cells and found evidence that beta-carotene stimulated vital cellular functions in the former and suppressed them in the latter. These differential effects correlated with the expression of the proapoptotic BCL2-associated X protein (BAX), which was downregulated in HUVECs and upregulated in the two neoplastic cell lines. The quantitative expression analysis using real-time polymerase chain reaction largely confirmed the inhibition of B-cell CLL/lymphoma 2 (BCL2) pathway-mediated apoptosis in HUVECs and its activation in melanoma and leukemic cells. The assays for apoptosis, detecting DNA breaks and caspase activation, showed consistent proapoptotic and antiapoptotic effects in U937 and HUVEC lines, respectively. However, beta-carotene-induced expression changes of BAX and other BCL2 pathway genes did not lead to the predicted induction of apoptosis in the A375 cells. PMID:15860445

  3. Biological effect of dose distortion by fiducial markers in spot-scanning proton therapy with a limited number of fields: A simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Matsuura, Taeko; Maeda, Kenichiro; Sutherland, Kenneth; Takayanagi, Taisuke; Shimizu, Shinichi; Takao, Seishin; Miyamoto, Naoki; Nihongi, Hideaki; Toramatsu, Chie; Nagamine, Yoshihiko; Fujimoto, Rintaro; Suzuki, Ryusuke; Ishikawa, Masayori; Umegaki, Kikuo; Shirato, Hiroki [Department of Medical Physics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, 060-8638 (Japan); Hitachi, Ltd., Hitachi Research Laboratory, 7-2-1 Omika-cho, Hitachi-shi, Ibaraki 319-1221 (Japan); Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, 060-8638 (Japan); Department of Medical Physics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, 060-8638 (Japan); Hitachi, Ltd., Hitachi Works, 3-1-1 Saiwai-cho, Hitachi-shi, Ibaraki 317-8511 (Japan); Hitachi, Ltd., Hitachi Research Laboratory, 7-2-1 Omika-cho, Hitachi-shi, Ibaraki 319-1221 (Japan); Department of Medical Physics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, 060-8638 (Japan); Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, 060-8638 (Japan)

    2012-09-15

    Purpose: In accurate proton spot-scanning therapy, continuous target tracking by fluoroscopic x ray during irradiation is beneficial not only for respiratory moving tumors of lung and liver but also for relatively stationary tumors of prostate. Implanted gold markers have been used with great effect for positioning the target volume by a fluoroscopy, especially for the cases of liver and prostate with the targets surrounded by water-equivalent tissues. However, recent studies have revealed that gold markers can cause a significant underdose in proton therapy. This paper focuses on prostate cancer and explores the possibility that multiple-field irradiation improves the underdose effect by markers on tumor-control probability (TCP). Methods: A Monte Carlo simulation was performed to evaluate the dose distortion effect. A spherical gold marker was placed at several characteristic points in a water phantom. The markers were with two different diameters of 2 and 1.5 mm, both visible on fluoroscopy. Three beam arrangements of single-field uniform dose (SFUD) were examined: one lateral field, two opposite lateral fields, and three fields (two opposite lateral fields + anterior field). The relative biological effectiveness (RBE) was set to 1.1 and a dose of 74 Gy (RBE) was delivered to the target of a typical prostate size in 37 fractions. The ratios of TCP to that without the marker (TCP{sub r}) were compared with the parameters of the marker sizes, number of fields, and marker positions. To take into account the dependence of biological parameters in TCP model, {alpha}/{beta} values of 1.5, 3, and 10 Gy (RBE) were considered. Results: It was found that the marker of 1.5 mm diameter does not affect the TCPs with all {alpha}/{beta} values when two or more fields are used. On the other hand, if the marker diameter is 2 mm, more than two irradiation fields are required to suppress the decrease in TCP from TCP{sub r} by less than 3%. This is especially true when multiple

  4. X-ray study of the critical behavior of V(2)H near the beta(,2)-beta(,2) phase transition in a defective near-surface volume and in the bulk

    Science.gov (United States)

    Trenkler, Johann

    We have observed two length scales in the critical x-ray diffuse scattering (CDS) from a VH0.525 crystal above the beta1-beta 2 phase transition where a sharp Lorentzian profile in the CDS was superimposed on a broader one. While no sharp component appeared in transmission geometry with high-energy x-rays, no broad component was detected in an experiment confined to a near-surface volume. Based on HERDA- and SNMS-measurements, the decay of the mosaic spread with increasing penetration, a larger d-spacing in the skin layer than in the bulk, and the above x-ray experiments, we conclude that the sharp component arises in the presence of a "defective" near-surface volume, while the broad component is associated with the pure bulk. For the defective skin layer, we observed a continuous phase transition allowing us to extract a tricritical exponent beta below TC, and tricritical exponents nu1 and gamma 1 for small reduced temperatures t = T/ TC -- 1. For larger t, the exponents nu and gamma are altered within the experimental range of t. Furthermore, the CDS of the defective skin layer is very anisotropic . The bulk, however, displays a strong discontinuous phase transition. This is not associated with a crossing of a two-phase region, nor with the small concentration H/V gradient within the upper 200 A, nor with a local (near-surface) ternary phase diagram due to an oxygen gradient in this region. The bulk displays an almost isotropic diffuse intensity above TC. In this work, we discuss the scaling and crossover behavior in the skin layer, the change of the order of the phase transition from the bulk to the skin layer associated with a change in the sign of the fourth order term in the Landau free energy expansion and the change of the correlation length with temperature, crystallographic direction and penetration. Furthermore, we qualitatively simulate the short-range order via Krivoglaz-Clapp-Moss and the Chepulskii-Bugaev RING approximations, taking into account the

  5. Effect of {beta}{sub 1} adrenergic receptor blockade on myocardial blood flow and vasodilatory capacity

    Energy Technology Data Exchange (ETDEWEB)

    Boettcher, M.; Czernin, J.; Sun, K. [Univ. of California, Los Angeles, CA (United States)] [and others

    1997-03-01

    The {beta}{sub 1} receptor blockade reduces cardiac work and may thereby lower myocardial blood flow (MBF) at rest. The effect of {beta}{sub 1} receptor blockade on hyperemic MBF is unknown. To evaluate the effect of selective {beta}{sub 1} receptor blockade on MBF at rest and during dipyridamole induced hyperemia, 10 healthy volunteers (8 men, 2 women, mean age 24 {+-} 5 yr) were studied using {sup 13}N-ammonia PET (two-compartment model) under control conditions and again during metoprolol (50 mg orally 12 hr and 1 hr before the study). The resting rate pressure product (6628 {+-} 504 versus 5225 {+-} 807) and heart rate (63 {+-} 6-54 {plus_minus} 5 bpm) declined during metoprolol (p < 0.05). Similarly, heart rate and rate pressure product declined from the baseline dipyridamole study to dipyridamole plus metoprolol (p < 0.05). Resting MBF declined in proportion to cardiac work by approximately 20% from 0.61 {+-} 0.09-0.51 {+-} 0.10 ml/g/min (p < 0.05). In contrast, hyperemic MBF increased when metoprolol was added to dipyridamole (1.86 {plus_minus} 0.27 {+-} 0.45 ml/g/min; p<0.05). The decrease in resting MBF together with the increase in hyperemic MBF resulted in a significant increase in the myocardial flow reserve during metoprolol (3.14 {+-} 0.80-4.61 {+-} 0.68; p<0.01). The {beta}{sub 1} receptor blockade increases coronary vasodilatory capacity and myocardial flow reserve. However, the mechanisms accounting for this finding remain uncertain. 32 refs., 2 figs., 2 tabs.

  6. Effect of hyperproduction of TEM-1 beta-lactamase on in vitro susceptibility of Escherichia coli to beta-lactam antibiotics.

    OpenAIRE

    Wu, P J; Shannon, K; Phillips, I

    1994-01-01

    The susceptibility of 173 TEM-1-producing isolates of Escherichia coli was assessed by determination of MICs by the agar dilution method. MICs of amoxicillin, mezlocillin, cephaloridine, and, to a smaller extent, amoxicillin-clavulanic acid (but not cephalexin, cefuroxime, cefotaxime, ceftazidime, or imipenem) were higher for isolates that produced large amounts of beta-lactamase than for isolates that produced smaller amounts. The effect of fixed concentrations of clavulanic acid on resistan...

  7. Biological Effects of the Great Oxidation Event

    Science.gov (United States)

    Schopf, J.

    2012-12-01

    Fossil evidence of photoautotrophy, documented in Precambrian sediments by stromatolites, stromatolitic microfossils, and carbon isotopic data consistent with autotrophic CO2-fixation, extends to ~3,500 Ma. Such data, however, are insufficient to establish the time of origin of O2-producing (cyanobacterial) photosynthesis from its anoxygenic, photosynthetic bacterial, evolutionary precursor. The oldest (Paleoarchean) stromatolites may have been formed by anoxygenic photoautotrophs, rather than the cyanobacteria that dominate Proterozoic and modern stromatolites. Unlike the cyanobacteria of Proterozoic microbial assemblages, the filamentous and coccoidal microfossils of Archean deposits may represent remnants of non-O2-producing prokaryotes. And although the chemistry of Archean organic matter shows it to be biogenic, its carbon isotopic composition is insufficient to differentiate between oxygenic and anoxygenic sources. Though it is well established that Earth's ecosystem has been based on autotrophy since its early stages and that O2-producing photosynthesis evolved earlier, perhaps much earlier, than the increase of atmospheric oxygen in the ~2,450 and ~2,320 Ma Great Oxidation Event (GOE), the time of origin of oxygenic photoautotrophy has yet to be established. Recent findings suggest that Earth's ecosystem responded more or less immediately to the GOE. The increase of atmospheric oxygen markedly affected ocean water chemistry, most notably by increasing the availability of biologically usable oxygen (which enabled the development of obligate aerobes, such as eukaryotes), and of nitrate, sulfate and hydrogen sulfide (the increase of H2S being a result of microbial reduction of sulfate), the three reactants that power the anaerobic basis of sulfur-cycling microbial sulfuretums. Fossil evidence of the earliest eukaryotes (widely accepted to date from ~1800 Ma and, arguably, ~2200 Ma) fit this scenario, but the most telling example of life's response to the GOE

  8. 'K' contribution to the biological effect of ionizing radiations

    International Nuclear Information System (INIS)

    The aim of this work is to determine the importance of 'K' ionizations on DNA as critical physical events initiating the biological effects of ionizing radiation, in particular in human cells. Ultra-soft X-rays are used as a probe of core ionization events. A decisive test consists in comparing the biological effects at 250 eV and 350 eV (before and after the carbon K - threshold). The results show a sharp increase of the biological efficiency for both cellular inactivation and chromosomal exchange aberration above the carbon K-threshold, correlated with the one of core events occurring in DNA atoms. The heavy ion irradiation displays again the paradoxical behaviour of cellular inactivation cross sections as a function of LET. Finally, the 'K' event contribution to cellular inactivation of usual low LET radiation is estimated to be about 75%. (author)

  9. Response-surface models for deterministic effects of localized irradiation of the skin by discrete {beta}/{gamma} -emitting sources

    Energy Technology Data Exchange (ETDEWEB)

    Scott, B.R.

    1995-12-01

    Individuals who work at nuclear reactor facilities can be at risk for deterministic effects in the skin from exposure to discrete {Beta}- and {gamma}-emitting ({Beta}{gamma}E) sources (e.g., {Beta}{gamma}E hot particles) on the skin or clothing. Deterministic effects are non-cancer effects that have a threshold and increase in severity as dose increases (e.g., ulcer in skin). Hot {Beta}{gamma}E particles are {sup 60}Co- or nuclear fuel-derived particles with diameters > 10 {mu}m and < 3 mm and contain at least 3.7 kBq (0.1 {mu}Ci) of radioactivity. For such {Beta}{gamma}E sources on the skin, it is the beta component of the dose that is most important. To develop exposure limitation systems that adequately control exposure of workers to discrete {Beta}{gamma}E sources, models are needed for systems that adequately control exposure of workers to discrete {Beta}{gamma}E sources, models are needed for evaluating the risk of deterministic effects of localized {Beta} irradiation of the skin. The purpose of this study was to develop dose-rate and irradiated-area dependent, response-surface models for evaluating risks of significant deterministic effects of localized irradiation of the skin by discrete {Beta}{gamma}E sources and to use modeling results to recommend approaches to limiting occupational exposure to such sources. The significance of the research results as follows: (1) response-surface models are now available for evaluating the risk of specific deterministic effects of localized irradiation of the skin; (2) modeling results have been used to recommend approaches to limiting occupational exposure of workers to {Beta} radiation from {Beta}{gamma}E sources on the skin or on clothing; and (3) the generic irradiated-volume, weighting-factor approach to limiting exposure can be applied to other organs including the eye, the ear, and organs of the respiratory or gastrointestinal tract and can be used for both deterministic and stochastic effects.

  10. Effect of biologic therapy on radiological progression in rheumatoid arthritis: what does it add to methotrexate?

    Directory of Open Access Journals (Sweden)

    Jones G

    2012-07-01

    Full Text Available Graeme Jones, Erica Darian-Smith, Michael Kwok, Tania WinzenbergMenzies Research Institute, University of Tasmania, Tasmania, AustraliaAbstract: There have been substantial advances in the treatment of rheumatoid arthritis in recent years. Traditional disease-modifying antirheumatic drugs (DMARDs have been shown to have small effects on the progression of radiographic damage. This quantitative overview summarizes the evidence for biologic DMARDS and radiographic damage either alone or in combination with methotrexate. Two outcomes were used (standardized mean difference and odds of progression. A total of 21 trials were identified of which 18 had useable data. For biologic monotherapy, tocilizumab, adalimumab, and etanercept were significantly better than methotrexate, with tocilizumab ranking first in both outcomes while golimumab was ineffective in both outcomes. For a biologic in combination with methotrexate compared with methotrexate alone, most therapies studied (etanercept, adalimumab, infliximab, certolizumab, tocilizumab, and rituximab were effective at slowing X-ray progression using either outcome, with infliximab ranking first in both outcomes. The exceptions to this were golimumab (no effect on standardized mean difference and abatacept (no effect on odds of progression. This effect was additional to methotrexate; thus, the overall benefit is moderate to large in magnitude, which is clearly of major clinical significance for sufferers of rheumatoid arthritis and supports the use of biologic DMARDs in those with a poor disease prognosis.Keywords: rheumatoid, trials, meta-analysis, radiographs, biologic, disease-modifying antirheumatic drugs, DMARDs

  11. Microscopic linear liquid streams in vacuum: Injection of solvated biological samples into X-ray free electron lasers

    International Nuclear Information System (INIS)

    Microscopic linear liquid free-streams offer a means of gently delivering biological samples into a probe beam in vacuum while maintaining the sample species in a fully solvated state. By employing gas dynamic forces to form the microscopic liquid stream (as opposed to a conventional solid-walled convergent nozzle), liquid free-streams down to 300 nm diameter have been generated. Such 'Gas Dynamic Virtual Nozzles' (GDVN) are ideally suited to injecting complex biological species into an X-ray Free Electron Laser (XFEL) to determine the structure of the biological species via Serial Femtosecond Crystallography (SFX). GDVN injector technology developed for this purpose is described.

  12. Quantitative and dynamic measurements of biological fresh samples with X-ray phase contrast tomography

    OpenAIRE

    Hoshino, Masato; Uesugi, Kentaro; Tsukube, Takuro; Yagi, Naoto

    2014-01-01

    X-ray phase contrast tomography using a Talbot grating interferometer was applied to biological fresh samples which were not fixed by any fixatives. To achieve a high-throughput measurement for the fresh samples the X-ray phase contrast tomography measurement procedure was improved. The three-dimensional structure of a fresh mouse fetus was clearly depicted as a mass density map using X-ray phase contrast tomography. The mouse fetus measured in the fresh state was then fixed by formalin and m...

  13. Current research in Canada on biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    A survey of current research in Canada on the biological effects of ionizing radiation has been compiled. The list of projects has been classified according to structure (organizational state of the test system) as well as according to the type of effects. Using several assumptions, ballpark estimates of expenditures on these activities have been made. Agencies funding these research activities have been tabulated and the break-down of research in government laboratories and in academic institutions has been designated. Wherever possible, comparisons have been made outlining differences or similarities that exist between the United States and Canada concerning biological radiation research. It has been concluded that relevant research in this area in Canada is inadequate. Wherever possible, strengths and weaknesses in radiation biology programs have been indicated. The most promising course for Canada to follow is to support adequately fundamental studies of the biological effects of radiation. (auth)

  14. Dissociation of beta-adrenoceptor-induced effects on amylase secretion and cyclic adenosine 3', 5' monophosphate accumulation.

    OpenAIRE

    Carlsöö, B.; Danielsson, A; Henriksson, R.; Idahl, L A

    1982-01-01

    By using a multi-channel microperifusion system the effects of noradrenaline, the beta1-adrenoceptor agonist prenalterol, and the beta2-selective agonist terbutaline were studied on amylase pig submandibular glands. 2 Noradrenaline caused significant amylase discharge and cyclic AMP accumulation. 3 Prenalterol was as effective as noradrenaline in causing amylase release but did not significantly affect the cyclic AMP content. 4 Terbutaline stimulated cyclic AMP accumulation, but had little ef...

  15. Effects of beta-adrenergic blocking agents on specific binding of [3H]D-Ala2-Met5-enkephalinamide and [3H]naloxone.

    OpenAIRE

    Takayama, Haruhiko; Ogawa,Norio; Asanuma, Masato; Hirata, Hiroshi; Ogura,Toshio; Ota,Zensuke

    1991-01-01

    To gain further insight into the central nervous system (CNS)-action of beta-adrenergic blocking agents (beta-blockers), we examined the effects of various kinds of beta-blockers on opioid receptors (Op-Rs) using radiolabeled receptor assay (RRA). We demonstrated that beta-blockers are competitively bound to Op-Rs in the CNS. Sodium index of beta-blockers in [3H]naloxone binding study indicated that beta-blockers had the mixed agonist-antagonist activity of opiates. The relative potency of be...

  16. The effect of alkali metal on the surface properties of potassium doped Au-Beta zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Sobczak, Izabela, E-mail: sobiza@amu.edu.pl [A. Mickiewicz University, Faculty of Chemistry, Grunwaldzka 6, 60-780 Poznan (Poland); Rydz, Michal; Ziolek, Maria [A. Mickiewicz University, Faculty of Chemistry, Grunwaldzka 6, 60-780 Poznan (Poland)

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► Interaction of gold with K leads to the change of electronic state and redox properties of gold. ► The amount of potassium incorporated into Au-zeolites determines the size of gold particles. ► K(0.2 wt.%)/Au-Beta exhibits the best performance in decomposition of N{sub 2}O and removal of Bu{sub 2}S. -- Abstract: Beta zeolite was applied as support for gold introduced by gold-precipitation method and potassium added by impregnation or adsorption. The effect of zeolite composition and the amount of potassium introduced on the surface properties of the final materials was considered. Moreover, the interaction of gold and potassium species was found to be related to the adsorptive and catalytic behaviour of zeolites in NO reduction with propene and deodorization. K/Au-Beta(Impregnated) exhibits the best performance in the above mentioned processes because of the small gold particles (between 2 and 5 nm) and interaction of gold with potassium species leading to the change of electronic properties of the surface (the appearance of cationic gold species). Potassium added as a promoter improves the catalytic properties of Au-zeolite in N{sub 2}O decomposition and also in deodorization (increase of the ability to dibutyl sulphide oxidation). The catalysts prepared were characterized by XRD, XPS, UV–vis, TEM, pyridine adsorption combined with FTIR and test reaction (2-propanol transformation).

  17. Effects of microstructural parameters and back stress on damage mechanisms in {alpha}/{beta} titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Helbert, A.L.; Feaugas, X.; Clavel, M. [Univ. de Technologie de Compiegne (France)

    1998-01-23

    Damage initiation and kinetics in four {alpha}/{beta} titanium alloys have been experimentally and numerically investigated. Efforts were focused on triaxiality, {chi} = {Sigma}{sub m}/{Sigma}{sub eq} and internal stresses effects. The study of void nucleation has provided nucleation criteria corresponding to voids at the {alpha}/{beta} interface. This macroscopic nucleation criterion, written as {Sigma}{sub m} = f({var_epsilon}{sub peq}), was explained with the help of microscopic observations. Microscopic parameters such as plastic strain in the {alpha}-phase or local hydrostatic stress {sigma}{sub m}{sup loc} at the {alpha}/{beta} interface have been linked to the damage initiation. Also, the influence of the different heterogeneity levels on the macroscopic nucleation criterion was demonstrated. It has also been shown that internal stresses increased both nucleation and growth kinetics. Damage mechanisms are well described by a Gurson-Tvergaard model modified to take into account internal stresses. In particular, the existence of a material physical property, f{sub c} (void volume fraction at fracture) was shown.

  18. Can {alpha}-tocopherol and {beta}-carotene supplementation reduce adverse radiation effects on salivary glands?

    Energy Technology Data Exchange (ETDEWEB)

    Funegaard, U.; Johansson, I.; Ericson, T. [Umeaa Univ. (Sweden). Dept. of Cariology; Malmer, B.; Henriksson, R. [Umeaa Univ. (Sweden). Dept. of Oncology

    1995-12-31

    In this study, we evaluated whether supplementation with antioxidant vitamins can reduce the adverse effects of irradiation on the salivary glands in the rat. Four groups of adult Sprague-Dawley rats were given a basic diet providing 0.6 mg {alpha}-tocopherol and no {beta}-carotene per day. In two groups the basic diet was supplemented with 3.4 mg {alpha}-tocopherol and 6 mg {beta}-carotene per day from 14 days before irradiation until 12 days after complete irradiation. One group of rats given basic diet and one group given supplemented diet were irradiated with 7 Gy daily for five consecutive days. Isoproterenol and pilocarpine-stimulated whole saliva was collected from all rats 2, 4 and 26 weeks after irradiation. Vitamin-supplemented irradiated rats had higher secretion rates on all three occasions compared with those of irradiated rats given basic diet. The changes in saliva composition seen in irradiated rats were less accentuated in vitamin-supplemented, irradiated rats. The proportions of acinar cells were significantly decreased both in parotid and submandibular glands 26 weeks after irradiation. Supplementation with {alpha}-tocopherol and {beta}-carotene did not alter the morphology of the glands. (author).

  19. Time-resolved x-ray studies of pressure-jump-induced topological transitions in biological membranes

    Science.gov (United States)

    Erramilli, Shyamsunder; Osterberg, Frederik; Gruner, Sol M.; Tate, Mark W.; Kriechbaum, Manfred

    1995-09-01

    Topological transitions in membrane liquid crystals formed by biological lipid-water systems have been the subject of much recent interest. We have developed an x-ray diffraction system capable of initiating pressure jumps of up to 3 kbar in about 5 ms. Time-resolved x-ray diffraction patterns were obtained (approximately 9 ms each) at the National Synchrotron Light Source using two state-of-the-art CCD based detectors developed at Princeton. Numerous Bragg diffraction patterns were obtained in studying the effect of pressure on the simplest topological transitions in membranes, the lamellar to hexagonal phase transition. The patterns from one of the detectors were recorded with a signal-to-noise sufficient to measure peak positions, peak widths, and integrated areas to an accuracy adequate to test models and mechanisms of phase transition kinetics. Additional longer time-scale studies were performed using optical turbidity measurements and were found to be consistent with x-ray studies. Transition rates were found to vary by nearly 5 orders of magnitude as the difference between the final pressure and the equilibrium transition pressure was varied. As the magnitude of the pressure jump in these lyotropic systems is increased, the transition mechanism is determined not only by the rate at which water and lipid molecules transform from one phase to the new emerging phase, but also by the need for water transport. Finally, it was found that the lamellar phase acts as an intermediate phase in transitions between the gel phase and the hexagonal phase, induced by very large pressure jumps (> 2 kbar).

  20. Effect of short-acting beta blocker on the cardiac recovery after cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    Qian Yanning

    2011-08-01

    Full Text Available Abstract The objective of this study was to investigate the effect of beta blocker on cardiac recovery and rhythm during cardiac surgeries. Sixty surgical rheumatic heart disease patients were received esmolol 1 mg/kg or the same volume of saline prior to removal of the aortic clamp. The incidence of cardiac automatic re-beat, ventricular fibrillation after reperfusion, the heart rate after steady re-beat, vasoactive drug use during weaning from bypass, the posterior parallel time and total bypass time were decreased by esmolol treatment. In conclusion: Esmolol has a positive effect on the cardiac recovery in cardiopulmonary bypass surgeries.

  1. Crystallization and preliminary X-ray analysis of beta-alanine synthase from the yeast Saccharomyces kluyveri

    DEFF Research Database (Denmark)

    Dobritzsch, D.; Gojkovic, Zoran; Andersen, Birgit;

    2003-01-01

    In eukaryotes and some bacteria, the third step of reductive pyrimidine catabolism is catalyzed by beta-alanine synthase (EC 3.5.1.6). Crystals of the recombinant enzyme from the yeast Saccharomyces kluyveri were obtained using sodium citrate as a precipitant. The crystals belong to space group P...

  2. Electron emission and biological consequences of hormones in polar media, studied on testosterone, progesterone, 17 beta-Estradiol and Genistein

    International Nuclear Information System (INIS)

    conditions, T induces strong proliferation of E. coli bacteria. These effects are both intensified, when T is combined with vitC. The present results offer a deeper insight in the biological behaviour of sex hormones and their metabolites. Possible reaction mechanisms of hormones and free radicals are presented, but further radiobiological investigations are required, as the reaction mechanisms are very complicated and overlap with many other biological processes. The pulse radiolysis method could essentially contribute to the elucidation of these processes. The combination experiments with vitC might show new approaches for the application of hormones in medical therapies. (author)

  3. Effect of alpha and beta adrenergic blockade on epinephrine induced pulmonary insufficiency.

    Science.gov (United States)

    Berk, J L; Hagen, J F; Koo, R

    1976-04-01

    Recent studies demonstrated that epinephrine causes significant pulmonary A-V shunting. This study reports the effect of alpha and beta adrenergic blockade on this shunting. Sixty-three anesthetized mongrel dogs were ventilated with a mechanical respirator. Measurements of (1) the pulmonary shunt, (2) cardiac output, (3) mean pulmonary artery, pulmonary capillary wedge and systemic pressures, and (4) pulmonary and systemic vascular resistances were obtained at 5, 15 and 30 minute intervals during the first hour and hourly for 5 hours. Fifteen dogs received no treatment. All others received epinephrine hydrochloride, 2 mug/kg/min for 5 hours. Ten received epinephrine only. Ten were pretreated with propranolol hydrochloride, 250 mug/kg, 12 with phenoxybenzamine, 1 mg/kg, and 16 with phenoxybenzamine and propranolol. Propranolol significantly decreased the epinephrine induced pulmonary shunt at all times and was the most effective drug. Phenoxybenzamine decreased the early shunting, but less than propranolol, and did not decrease the late shunting. Blockade with propranolol and phenoxybenzamine was less effective than propranolol alone. Based on the observed hemodynamic changes it was suggested that beta blockade is effective in reducing epinephrine induced pulmonary insufficiency by favorably altering the flow and distribution of pulmonary blood flow which in turn decreases epinephrine induced ventilation-perfusion inequalities and capillary hypertension both of which result in shunting. Conversely phenoxybenzamine has an unfavorable effect on the pulmonary flow. These studies support previous work in animals and man which showed that beta adrenergic stimulation is important in the pathogenesis of pulmonary insufficiency. Because the amounts of epinephrine used produce blood levels observed in critical illness, these studies add support to a relationship between the increased catecholamine stimulation of critical illness and the associated and often unexplained

  4. Biological effects at low irradiation doses

    International Nuclear Information System (INIS)

    Full text: The best scientific evidence of radiation effects in humans initially came from epidemiological studies of atomic bomb survivors in Hiroshima and Nagasaki. While no evidence of genetic effects has been found, these studies showed a roughly linear relationship between the induction of cancer and extremely high dose-rate of atomic bomb radiation. This was consistent with the knowledge that ionizing radiation can damage DNA in linear proportion to high-dose exposures and so produces gene mutations known to be associated with cancer. In the absence of comparable low dose effects it was prudent to propose tentatively the no-threshold hypothesis (LNT) that extrapolates linearly from effects observed at very high doses to the same effects at very low doses. It was accepted by the International Commission on Radiological Protection (ICRP) and afterwards adopted by national radiation protection organizations to guide regulations for the protection of occupationally exposed workers and the public. This hypothesis that all radiation is harmful in linear proportion to the dose is the principle used for collective dose calculations of the number of deaths produced by any radiation, natural of generated, no matter how small (BEIR-2000). The National Council of Radiation Protection and Measurements Report 121, summarizes the basis for adherence to linearity of radiation health effects. Confidence in LNT at low doses is based on our understanding of the basic mechanisms involved. Genetic effects may result from a gene mutation or a chromosome aberration. The activation of a dominant acting oncogene is frequently associated with leukemia and lymphomas, while the loss of suppressor genes appears to be more frequently associated with solid tumors. It is conceptually possible, but with a vanishing small probability, that any of these effects could result from the passage of a single charged particle, causing damage to DNA that could be expressed as a mutation or small

  5. Biological effects and hazards of radiation exposure

    International Nuclear Information System (INIS)

    Radiation induced carcinogenesis and mutagenesis form the main risk to health from exposure to low levels of radiation. This risk effects can be at least qualitatively understood by considering the effects of radiation on cell DNA. Whilst exposure to high levels of radiation results in a number of identifiable effects, exposure to low levels of radiation may result in effects which only manifest themselves after many years. Risk estimates for low levels of radiation have been derived on the basis of a number of assumptions. In the case of uranium mine workers a major hazard arises from the inhalation of radon daughters. Whilst the correlation between radon daughter exposure and lung cancer incidence is well established, the numerical value of the risk factor is the subject of controversy. ICRP 50 gives a value of 10 cases per 106 person-years at risk per WLM (range 5-15 x 10-6 PYR-1 WLM-1). The effect of smoking on lung cancer incidence rates amongst miners is also controversial. Nevertheless, smoking by miners should be discouraged

  6. Low immunogenicity but reduced bioavailability of an interferon beta-1a biosimilar compared with its biological parent: results of MATRIX, a cross-sectional, multicenter phase 4 study

    Directory of Open Access Journals (Sweden)

    Cuevas C

    2015-09-01

    Full Text Available Carlos Cuevas,1 Florian Deisenhammer,2 Xiaojun You,3 Mariano Scolnik,4 Regine Buffels,3 Bjørn Sperling,3 Francisco Flores-Ramírez,5 Miguel Macías-Islas,6 Sergio Sauri-Suárez7 On behalf of the MATRIX Investigator Group 1Specialty Hospital, Department of Neurology, National Medical Center Siglo XXI, Mexican Institute of Social Security, Mexico City, Mexico; 2Department of Neurology, University of Innsbruck, Innsbruck, Austria; 3Biogen, Cambridge, MA, USA; 4Biogen, Argentina, Buenos Aires, Argentina; 5Department of Internal Medicine–Neurology, Hospital Regional ISSSTE Monterrey, Monterrey, 6University Center for Health Sciences, University of Guadalajara, Guadalajara, 7Internal Medicine/Department of Neurology, National Medical Center, Mexico City, Mexico Abstract: MATRIX (Measuring neutralizing Antibodies in patients TReated with Interferon beta-1a IM in MeXico was primarily a cross-sectional phase 4 study of patients with relapsing multiple sclerosis (RMS that evaluated neutralizing antibody (NAb frequency in Mexican and Colombian patients treated with intramuscular interferon (IFN beta-1a in the form of Avonex® or the biosimilar drug Jumtab®. A secondary long-term retrospective observational evaluation of safety, tolerability, and relapses was also performed for patients in each arm of the study. In the cross-sectional portion of the study, patients with multiple sclerosis who had been treated with once-weekly Avonex (n=36 or Jumtab (n=29 self-injections as their first and only disease-modifying therapy for 1–3 years were retrospectively identified. The primary and secondary endpoints were proportion of patients with NAb levels >100 tenfold reduction units (TRU and >20 TRU. The biological response to IFN beta-1a injections was assessed by change in serum neopterin levels and by pre- versus post-dose concentration difference. Safety, tolerability, and relapse-related information were also retrospectively assessed. No patients developed

  7. Titanium dioxide nanoparticles – Biological effects

    OpenAIRE

    Anna Maria Świdwińska-Gajewska; Sławomir Czerczak

    2014-01-01

    Titanium dioxide occurs as particles of various sizes. Particles of up to 100 nm, corresponding to nanoparticles, and in the size range of 0.1–3 mm are the most frequently used. Titanium dioxide in a bulk form is not classified as dangerous substance, nevertheless nanoparticles may cause adverse health effects. Inhalation exposure to nano-TiO2 causes pulmonary inflammation that may lead to fibrotic and proliferative changes in the lungs. Many studies confirm the genotoxic effect of TiO2, espe...

  8. Three approaches for direct analysis of biological samples by Total reflection X-Ray Fluorescence analysis

    International Nuclear Information System (INIS)

    One of the main advantages of the Total reflection X-Ray Fluorescence technique is feasibility of the direct analysis of the sample. taking in account this fact, three methods for the direct analysis of biological samples were evaluated For the evaluation of the method of Compton peak standardization serum, brain tissue, urine and amniotic fluid matrices were analyzed using compton Peak and the elements Co, and V as internal standard. In the case the sample itself is used as calibration standard. The method is reliable for the analysis of serum and brain tissue samples. The analytical quality of the results was similar to that obtained by the conventional method. The results were in good agreements with those obtained by the atomic absorption technique. The second method was applied to the certified Bovine Liver Standard sample 1577a. Experimental conditions for the microwave acid digestion of the solid sample directly on the quartz reflector were found, The percent of recovery of the elements S, Ci, K, Ca, Mn, Fe, Cu, Zn, Se, Br, and Rb carried between 85% and 115% and The precision was below the 10% of relative standards deviations for ten independent replicates. In the third method the concept of chemical modifications is adapted to the Total reflection X-Ray Fluorescence technique. In these experiments the main objective was the elimination of Chlorine from the matrix following the in situ addition of the reactive ammonium nitrate and heating. The method was applied to high saline content samples, i.e. amniotic fluid samples, Special care was given to the volatile elements and to the quality of the thin layer. an enhancement of the sensitivity was found for those elements with signals near the chlorine k-Alfa signal after the modifications procedure

  9. Sensitivity of $\\beta$-decay rates to the radial dependence of the nucleon effective mass

    CERN Document Server

    Severyukhin, A P; Borzov, I N; Van Giai, Nguyen

    2015-01-01

    We analyze the sensitivity of $\\beta$-decay rates in 78 Ni and 100,132 Sn to a correction term in Skyrme energy-density functionals (EDF) which modifies the radial shape of the nucleon effective mass. This correction is added on top of several Skyrme parametrizations which are selected from their effective mass properties and predictions about the stability properties of 132 Sn. The impact of the correction on high-energy collective modes is shown to be moderate. From the comparison of the effects induced by the surface-peaked effective mass in the three doubly magic nuclei, it is found that 132 Sn is largely impacted by the correction, while 78 Ni and 100 Sn are only moderately affected. We conclude that $\\beta$-decay rates in these nuclei can be used as a test of different parts of the nuclear EDF: 78 Ni and 100 Sn are mostly sensitive to the particle-hole interaction through the B(GT) values, while 132 Sn is sensitive to the radial shape of the effective mass. Possible improvements of these different parts...

  10. Radiation and their deleterious effects: special respect to X-ray

    International Nuclear Information System (INIS)

    Radiation have been influencing the living and non living systems on earth, since their evolution from simple, humble beginnings to diversely complex system of the present day biological world. Most of the radiations have been the basis for conduction and completion of vital life processes like photosynthesis which form the base and initiation point of flow of energy within the biological world. However there are some radiation called as ionizing radiation with energy content of more then 124 eV, which have the capacity to cause deleterious effects in livings system ranging from simple unicellular organisms to the large and complex animals and plants. The discovery of X-ray by William Conrad Roentgen in 1898 provided the originating point for radiation biology as a well defined discipline. Together with the discovery of X-ray radioactivity and new radioactive elements the biological effects of ionizing radiation began to be studied immediately after the discovery of X-ray. By the year 1896 press reports regarding the skin injuries involved skin erythemas and ulceration in persons who experienced the frequent and prolonged action of X-ray had appeared. By 1959, 359 radiologists were known to have died of X-ray induced cancer of skin or of leukemia. The deleterious effects of radiation on a large scale became evident when a large number of deaths, approximately 10,300 had occurred when USA dropped atom bomb on the Japanese towns of Hiroshima and Nagasaki, leaving about 80,000 persons injured. The effects of these two explosions are still evident in generation of today and also these twin incidents evoked awareness among the researchers to investigate the nature and effects of radiation which they cause in living beings. (author)

  11. Biological Effects of Neutron and Proton Irradiations. Vol. I. Proceedings of the Symposium on Biological Effects of Neutron Irradiations

    International Nuclear Information System (INIS)

    During recent years the interest in biological effects caused by neutrons has been increasing steadily as a result of the rapid development of neutron technology and the great number of neutron sources being used. Neutrons, because of their specific physical characteristics and biological effects, form a special type of radiation hazard but, at the same time, are a prospective tool for applied radiobiology. This Symposium, held in Brookhaven at the invitation of the United States Government from 7-11 October 1963, provided an opportunity for scientists to discuss the experimental information at present available on the biological action of neutrons and to evaluate future possibilities. It was a sequel to the Symposium on Neutron Detection, Dosimetry and Standardization, which was organized by the International Atomic Energy Agency in December 1962 at Harwell. The Symposium was attended by 128 participants from 17 countries and 6 international organizations. Fifty-four papers were presented. The following subjects were discussed in various sessions: (1) Dosimetry. Estimation of absorbed dose of neutrons in biological material. (2) Biological effects of high-energy protons. (3) Cellular and genetic effects. (4) Pathology of neutron irradiation, including acute and chronic radiation syndromes (mortality, anatomical and histological changes, biochemical and metabolic disturbances) and delayed consequences. (5) Relative biological effectiveness of neutrons evaluated by different biological tests. A Panel on Biophysical Considerations in Neutron Experimentation, with special emphasis on informal discussions, was organized during the Symposium. The views of the Panel are recorded in Volume II of the Proceedings. Many reports were presented on the important subject of the relative effectiveness of the biological action of neutrons, as well as on the general pathology of neutron irradiation and the cellular and genetic effects related to it. Three survey papers considered

  12. Biological Effects of Neutron and Proton Irradiations. Vol. II. Proceedings of the Symposium on Biological Effects of Neutron Irradiations

    International Nuclear Information System (INIS)

    During recent years the interest in biological effects caused by neutrons has been increasing steadily as a result of the rapid development of neutron technology and the great number of neutron sources being used. Neutrons, because of their specific physical characteristics and biological effects, form a special type of radiation hazard but, at the same time, are a prospective tool for applied radiobiology. This Symposium, held in Brookhaven at the invitation of the United States Government from 7-11 October 1963, provided an opportunity for scientists to discuss the experimental information at present available on the biological action of neutrons and to evaluate future possibilities. It was a sequel to the Symposium on Neutron Detection, Dosimetry and Standardization, which was organized by the International Atomic Energy Agency in December 1962 at Harwell. The Symposium was attended by 128 participants from 17 countries and 6 international organizations. Fifty-four papers were presented. The following subjects were discussed in various sessions: (1) Dosimetry. Estimation of absorbed dose of neutrons in biological material. (2) Biological effects of high-energy protons. (3) Cellular and genetic effects. (4) Pathology of neutron irradiation, including acute and chronic radiation syndromes (mortality, anatomical and histological changes, biochemical and metabolic disturbances) and delayed consequences. (5) Relative biological effectiveness of neutrons evaluated by different biological tests. A Panel on Biophysical Considerations in Neutron Experimentation, with special emphasis on informal discussions, was organized during the Symposium. The views of the Panel are recorded in Volume II of the Proceedings. Many reports were presented on the important subject of the relative effectiveness of the biological action of neutrons, as well as on the general pathology of neutron irradiation and the cellular and genetic effects related to it. Three survey papers considered

  13. Predictive modeling of nanomaterial exposure effects in biological systems

    OpenAIRE

    Liu X; Tang K.; Harper S.; Harper B; Steevens JA; Xu R

    2013-01-01

    Xiong Liu,1 Kaizhi Tang,1 Stacey Harper,2 Bryan Harper,2 Jeffery A Steevens,3 Roger Xu1 1Intelligent Automation, Inc., Rockville, MD, USA; 2Department of Environmental and Molecular Toxicology, School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR, USA; 3ERDC Environmental Laboratory, Vicksburg, MS, USA Background: Predictive modeling of the biological effects of nanomaterials is critical for industry and policymakers to assess the potential ha...

  14. Biological and therapeutical effects of Radon

    Energy Technology Data Exchange (ETDEWEB)

    Deetjen, P. [Institute of Physiologie and Balneologie, University of Innsbruck (Austria)

    1998-12-31

    In spas with a somewhat elevated Radon{sup 222} (Rn) activity (between 300 and 3000 Bq/l), the empirical medicine ended - in all parts of the world - with the same list of indications. It mainly includes the more painful rheumatic diseases such as deformation or degeneration of the joints and non bacterial inflammation of muscles, tendons or joints; Morbus Bechterew and other diseases of the vertebral column like spondylosis, spondylarthrosis or osteochondrosis. While informer times these effects were seldom documented in an objective manner, in recent years several prospective randomized double-blind studies proved the pain reducing efficacy of Radon therapy in patients with cervical pain syndromes, with chronic polyarthritis or with Morbus Bechterew. Studies in experimental animal models have accumulated remarkable data in organs, tissue and cultured cells that provide a rationale to explain the observed effects of Radon therapy in patients. (author)

  15. Biological and therapeutical effects of Radon

    International Nuclear Information System (INIS)

    In spas with a somewhat elevated Radon222 (Rn) activity (between 300 and 3000 Bq/l), the empirical medicine ended - in all parts of the world - with the same list of indications. It mainly includes the more painful rheumatic diseases such as deformation or degeneration of the joints and non bacterial inflammation of muscles, tendons or joints; Morbus Bechterew and other diseases of the vertebral column like spondylosis, spondylarthrosis or osteochondrosis. While informer times these effects were seldom documented in an objective manner, in recent years several prospective randomized double-blind studies proved the pain reducing efficacy of Radon therapy in patients with cervical pain syndromes, with chronic polyarthritis or with Morbus Bechterew. Studies in experimental animal models have accumulated remarkable data in organs, tissue and cultured cells that provide a rationale to explain the observed effects of Radon therapy in patients. (author)

  16. Biological Effects of Low Level Laser Therapy

    OpenAIRE

    Farivar, Shirin; Malekshahabi, Talieh; Shiari, Reza

    2014-01-01

    The use of low level laser to reduce pain, inflammation and edema, to promote wound, deeper tissues and nerves healing, and to prevent tissue damage has been known for almost forty years since the invention of lasers. This review will cover some of the proposed cellular mechanisms responsible for the effect of visible light on mammalian cells, including cytochrome c oxidase (with absorption peaks in the Near Infrared (NIR)). Mitochondria are thought to be a likely site for the initia...

  17. Palytoxin and Analogs: Biological and Ecological Effects

    Directory of Open Access Journals (Sweden)

    Vítor Ramos

    2010-06-01

    Full Text Available Palytoxin (PTX is a potent marine toxin that was originally found in soft corals from tropical areas of the Pacific Ocean. Soon after, its occurrence was observed in numerous other marine organisms from the same ecological region. More recently, several analogs of PTX were discovered, remarkably all from species of the dinoflagellate genus Ostreopsis. Since these dinoflagellates are also found in other tropical and even in temperate regions, the formerly unsuspected broad distribution of these toxins was revealed. Toxicological studies with these compounds shows repeatedly low LD50 values in different mammals, revealing an acute toxic effect on several organs, as demonstrated by different routes of exposure. Bioassays tested for some marine invertebrates and evidences from environmental populations exposed to the toxins also give indications of the high impact that these compounds may have on natural food webs. The recognition of its wide distribution coupled with the poisoning effects that these toxins can have on animals and especially on humans have concerned the scientific community. In this paper, we review the current knowledge on the effects of PTX and its analogs on different organisms, exposing the impact that these toxins may have in coastal ecosystems.

  18. Biological effects of heavy ions on small animals in soil and plants

    International Nuclear Information System (INIS)

    We have studied the biological effects of low linear energy transfer (LET) radiation on small animals in soil and plants, which are recognized to play an important role in maintenance of terrestrial ecosystem. However, the effects of high LET radiation must be also considered because many radiation sources in environment could be alpha and beta emitters as well as gamma emitters. As the pilot study, the effect of high LET radiation on Enchytraeus japonensis, a terrestrial earthworm was evaluated with heavy ions at NIRS-HIMAC. The earthworm was exposed to C, Ne, Si, Ar or Fe ion with the energy of 290, 400, 490, 500 and 500 MeV/u, respectively. The earthworm was then reared on plain agar medium in disposable Petri dishes, and the number of worms was enumerated 3 weeks after irradiation. Unfortunately a significant part of HIMAC machine time initially allocated for this study had to be cancelled due to unexpected long-term closing of an experimental facility where the earthworm was reared. Therefore, more than two times of experiments were achieved only in irradiation with Ar ion. The inhibitory effect of Ar ion on the growth of the earthworm was larger than low LET radiation. The relative biological effectiveness (RBE) was approximately 3. (author)

  19. Exposure of bremsstrahlung from beta-emitting therapeutic radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Manjunatha, H.C. [Department of Physics, Bangalore University, Bangalore-560056, Karnataka (India)], E-mail: manjunathhc@rediffmail.com; Rudraswamy, B. [Department of Physics, Bangalore University, Bangalore-560056, Karnataka (India)

    2009-02-15

    There has been an increased interest in beta therapeutic nuclear medicine, which emits relatively high-energy (>1 MeV) {beta}-rays and the production in vivo of Bremsstrahlung sufficient for external imaging, the produced Bremsstrahlung radiation hazard warrants evaluation. The Bremsstrahlung dose from patient administered {beta}-ray emitted radionuclide has been calculated by extending the national council on Radiation Protection and measurement model of a point source in air to account for biologic elimination of activity. We have estimated the probability of bremsstrahlung production, specific Bremsstrahlung constant (defined by Zanzonico et al.) and activity (A{sub release}) in bone cortical, bone compact, different regions of tooth enamel (enamel dentin junction (EDJ), enamel middle surface, enamel inner surface), different regions of dentin (outer surface, middle surface, enamel dentin junction (EDJ)), soft tissue, lungs and skeleton for different therapeutic beta-emitting radionuclide. In the present calculations we have used modified atomic number (Z{sub mod}) defined for bremsstrahlung process. Proper localization and quantification of incorporated beta emitters in bone and tooth are possible, because Bremsstrahlung production is greater in bone and tooth than soft tissue due to their high modified atomic number (Z{sub mod}). Radionuclide therapy with pure {beta}-ray emitters emitted in bone, tooth, soft tissue, lungs and skeleton does not require medical confinement of patients for radiation protection.

  20. Effect of beta-adrenergic blockade on elevated arterial compliance and low systemic vascular resistance in cirrhosis

    DEFF Research Database (Denmark)

    Møller, S; Bendtsen, F; Henriksen, Jens Henrik Sahl

    2001-01-01

    beta-blockers, but the effect of this treatment on arterial compliance has not been investigated. The aim of the present study was therefore to assess the effects of propranolol on the arterial compliance of patients with cirrhosis. METHODS: Twenty patients with cirrhosis underwent a haemodynamic......) of 17.8 mmHg, and responded to beta-blocker treatment with a significant reduction in the HVPG (-16%; P < 0.001). Arterial compliance was elevated (1.27 versus controls 1.01 ml/mmHg; P < 0.001), but remained almost unchanged during beta-adrenergic blockade (1.27 versus 1.29 ml/mmHg, +2%, ns), whereas...... beta-blockers increases small vessel (arteriolar) vascular tone towards the normal level, but does not affect the elevated compliance of the larger arteries in patients with cirrhosis....