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Radiation
Kinds of Radiation Terms modified by Radiation Selected AbstractsNATURAL HISTORY, ECOLOGY, AND EVOLUTION OF A REMARKABLE ADAPTIVE RADIATIONEVOLUTION, Issue 5 2010Steven M. Vamosi No abstract is available for this article. [source] EFFECT OF IONIZING RADIATION ON BEEF BOLOGNA CONTAINING SOY PROTEIN CONCENTRATEJOURNAL OF FOOD SAFETY, Issue 3 2001C.H. SOMMERS ABSTRACT Soy protein concentrate (SPC), an extender, is a common additive in ready-to-eat (RTE) meat products. SPC contains antioxidants that could potentially interfere with the ability of ionizing radiation to eliminate Listeria monocytogenes from RTE meat products. When L. monocytogenes was inoculated into cooked beef bologna emulsion containing 0, 1.75, or 3.5% SPC the gamma radiation D10 values, at radiation doses of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 kGy, were 0.66, 0.68, and 0.71kGy, respectively. Soluble antioxidant power, as determined by the Ferric Reducing Antioxidant Power (FRAP) assay was 1958, 3572, and 5494 mol in bologna emulsion containing 0, 1.75 and 3.5% SPC, respectively. Soluble antioxidant power was not affected by ionizing radiation. SPC did not prevent ionizing radiation induced lipid oxidation as determined by Thiobarbituric Acid Reactive Substance (TBARS) assay. Hunter color analysis of both unirradiated and irradiated bologna slices containing SPC indicated decreased a value as a result of irradiation, while the addition of SPC helped maintain b-value and L-value. The inclusion of SPC did not represent a barrier to ionizing radiation pasteurization of fine emulsion sausages for the parameters examined. [source] IMPACTS OF SOLAR UV RADIATION ON THE PHOTOSYNTHESIS, GROWTH, AND UV-ABSORBING COMPOUNDS IN GRACILARIA LEMANEIFORMIS (RHODOPHYTA) GROWN AT DIFFERENT NITRATE CONCENTRATIONS,JOURNAL OF PHYCOLOGY, Issue 2 2009Yangqiao Zheng Solar ultraviolet radiation (UVR, 280,400 nm) is known to affect macroalgal physiology negatively, while nutrient availability may affect UV-absorbing compounds (UVACs) and sensitivity to UVR. However, little is known about the interactive effects of UVR and nitrate availability on macroalgal growth and photosynthesis. We investigated the growth and photosynthesis of the red alga Gracilaria lemaneiformis (Bory) Grev. at different levels of nitrate (natural or enriched nitrate levels of 41 or 300 and 600 ,M) under different solar radiation treatments with or without UVR. Nitrate-enrichment enhanced the growth, resulted in higher concentrations of UVACs, and led to negligible photoinhibition of photosynthesis even at noon in the presence of UVR. Net photosynthesis during the noon period was severely inhibited by both ultraviolet-A radiation (UVA) and ultraviolet-B radiation (UVB) in the thalli grown in seawater without enriched nitrate. The absorptivity of UVACs changed in response to changes in the PAR dose when the thalli were shifted back and forth from solar radiation to indoor low light, and exposure to UVR significantly induced the synthesis of UVACs. The thalli exposed to PAR alone exhibited higher growth rates than those that received PAR + UVA or PAR + UVA + UVB at the ambient or enriched nitrate concentrations. UVR inhibited growth approximately five times as much as it inhibited photosynthesis within a range of 60,120 ,g UVACs · g,1 (fwt) when the thalli were grown under nitrate-enriched conditions. Such differential inhibition implies that other metabolic processes are more sensitive to solar UVR than photosynthesis. [source] PHOTOSYNTHETIC INSENSITIVITY OF THE TERRESTRIAL CYANOBACTERIUM NOSTOC FLAGELLIFORME TO SOLAR UV RADIATION WHILE REHYDRATED OR DESICCATED,JOURNAL OF PHYCOLOGY, Issue 4 2007Kunshan Gao Photosynthetic performance of the terrestrial cyanobacterium Nostoc flagelliforme (M. J. Berkeley et M. A. Curtis) Bornet et Flahault during rehydration and desiccation has been previously characterized, but little is known about the effects of solar UV radiation (280,400 nm) on this species. We investigated the photochemical activity during rehydration and subsequent desiccation while exposing the filamentous colonies to different solar radiation treatments. Photochemical activity could be reactivated by rehydration under full-spectrum solar radiation, the species being insensitive to both ultraviolet-A radiation (UVAR; 315,400 nm) and ultraviolet-B radiation (UVBR). When the rehydrated colonies were exposed for desiccation, the effective PSII photochemical yield was inhibited by visible radiation (PAR) at the initial stage of water loss, then increased with further decrease in water content, and reached its highest value at the water content of 10%,30%. However, no significant difference was observed among the radiation treatments except for the moment when they were desiccated to critical water content of about 2%,3%. At such a critical water content, significant reduction by UVBR of the effective quantum yield was observed in the colonies that were previously rehydrated under indoor light [without ultraviolet radiation (UVR)], but not in those reactivated under scattered or direct solar radiation (with UVR), indicating that preexposure to UVR during rehydration led to higher resistance to UVR during desiccation. The photosynthetic CO2 uptake by the desiccated colonies was enhanced by elevation of CO2 but was not affected by both UVAR and UVBR. It increased with enhanced desiccation to reach the maximal values at water content of 40%,50%. The UV-absorbing compounds and the colony sheath were suggested to play an important role in screening harmful UVR. [source] EFFECTS OF UV RADIATION ON GROWTH AND PHLOROTANNINS IN FUCUS GARDNERI (PHAEOPHYCEAE) JUVENILES AND EMBRYOS,JOURNAL OF PHYCOLOGY, Issue 3 2004Brianne E. Henry Diminishing levels of atmospheric ozone are increasing UV stress on intertidal algae. Early developmental stages tend to be more susceptible to environmental stresses; however, little research has examined how these stages are protected from UV radiation (UVR). Many brown algae contain high levels of phlorotannins, which are thought to function in screening UVR. In this study, we tested the effects of ambient levels of UV-B and UV-A on growth and phlorotannin production in 1- to 2-cm juvenile and microscopic postsettlement embryos of the intertidal alga Fucus gardneri Silva. Algae were grown in four light treatments: 1) ambient light; 2) under cellulose acetate, which lowered light quantity but did not affect light quality; 3) under MylarTM, which filtered UV-B; and 4) under PlexiglasTM, which blocked UV-A and UV-B. Over a 3-week period, UV-B inhibited and UV-A enhanced the growth of F. gardneri embryos, whereas the growth of juveniles was not affected. Phlorotannin concentrations of both embryos and juveniles did not differ in any of the light treatments. Our results suggest that embryos of F. gardneri are susceptible to UV light but develop a tolerance to it as they mature. This tolerance may result from increases in phlorotannin concentrations that occur during maturation; however, phlorotannin production in embryonic or juvenile stages is either not induced by UV light or takes more than 3 weeks to occur. [source] THE MESOZOIC RADIATION OF EUKARYOTIC ALGAE: THE PORTABLE PLASTID HYPOTHESIS,JOURNAL OF PHYCOLOGY, Issue 2 2003Daniel Grzebyk Although all chloroplasts appear to have been derived from a common ancestor, a major schism occurred early in the evolution of eukaryotic algae that gave rise to red and green photoautotrophic lineages. In Paleozoic and earlier times, the fossil record suggests that oceanic eukaryotic phytoplankton were dominated by the green (chl b -containing) algal line. However, following the end-Permian extinction, a diverse group of eukaryotic phytoplankton evolved from secondary symbiotic associations in the red (chl c -containing) line and subsequently rose to ecological prominence. In the contemporary oceans, red eukaryotic phytoplankton taxa continue to dominate marine pelagic food webs, whereas the green line is relegated to comparatively minor ecological and biogeochemical roles. To help elucidate why the oceans are not dominated by green taxa, we analyzed and compared whole plastid genomes in both the red and green lineages. Our results suggest that whereas all algal plastids retain a core set of genes, red plastids retain a complementary set of genes that potentially confer more capacity to autonomously express proteins regulating oxygenic photosynthetic and energy transduction pathways. We hypothesize that specific gene losses in the primary endosymbiotic green plastid reduced its portability for subsequent symbiotic associations. This corollary of the plastid "enslavement" hypothesis may have limited subsequent evolutionary advances in the green lineage while simultaneously providing a competitive advantage to the red lineage. [source] DETERMINATION OF PIGMENTS AND BINDERS IN POMPEIAN WALL PAINTINGS USING SYNCHROTRON RADIATION , HIGH-RESOLUTION X-RAY POWDER DIFFRACTION AND CONVENTIONAL SPECTROSCOPY , CHROMATOGRAPHYARCHAEOMETRY, Issue 2 2010A. DURAN The employment of synchrotron techniques complemented by conventional laboratory systems has allowed us to deepen and improve our knowledge of Roman wall painting procedures. The palette identified in wall paintings from Pompeii and Herculaneum from the second century bc includes goethite, hematite, cinnabar, glauconite, Egyptian blue, and other components such as calcite and aragonite. Proof of the use of organic binders is provided by FTIR and PY,GC/MS. Therefore, the possibility of the use of ,a secco' techniques cannot be ruled out. Pigments in wall paintings are usually found in small percentages and conventional X-ray diffractometers do not detect them. Synchrotron radiation , high-resolution X-ray powder diffraction has allowed identification with only a few micrograms of sample. [source] EXTINCTION DURING EVOLUTIONARY RADIATIONS: RECONCILING THE FOSSIL RECORD WITH MOLECULAR PHYLOGENIESEVOLUTION, Issue 12 2009Tiago B. Quental Recent application of time-varying birth,death models to molecular phylogenies suggests that a decreasing diversification rate can only be observed if there was a decreasing speciation rate coupled with extremely low or no extinction. However, from a paleontological perspective, zero extinction rates during evolutionary radiations seem unlikely. Here, with a more comprehensive set of computer simulations, we show that substantial extinction can occur without erasing the signal of decreasing diversification rate in a molecular phylogeny. We also find, in agreement with the previous work, that a decrease in diversification rate cannot be observed in a molecular phylogeny with an increasing extinction rate alone. Further, we find that the ability to observe decreasing diversification rates in molecular phylogenies is controlled (in part) by the ratio of the initial speciation rate (Lambda) to the extinction rate (Mu) at equilibrium (the LiMe ratio), and not by their absolute values. Here we show in principle, how estimates of initial speciation rates may be calculated using both the fossil record and the shape of lineage through time plots derived from molecular phylogenies. This is important because the fossil record provides more reliable estimates of equilibrium extinction rates than initial speciation rates. [source] Stabilization of Radiation-Condensation Instability by Light Impurity InjectionCONTRIBUTIONS TO PLASMA PHYSICS, Issue 3-5 2010A. A. Pshenov Abstract As it has been shown in [1,2], Radiation-Condensation Instability (RCI) may initiate Microfaceted Asymmetric Radiation from the Edge (MARFE) in tokamaks (see also review papers [3-5]). Nevertheless, experiments demonstrate the stable regimes with strongly radiated edge plasmas after Ne injection [6-8] or in siliconized discharges. Two effects destabilize radiative plasmas, the decrease of radiation losses Q with the electron temperature Te increase, and the increase of Q with electron and impurity densities rise. The finite relaxation time of impurity distribution over ionization states [6] as well as the thermal force acting on the growth rate doesn't shift the instability margin. Hence, one can examine the stability margin using the approximation of the coronal equilibrium. Radiation losses of intrinsic impurities like beryllium, carbon and nitrogen usually decrease with the temperature increase at the temperature range typical for the edge (see Fig. 1, curve 1). The situation may be significantly different for impurity mixtures. Radiation losses L , Q /(nenI)normalized by electron and impurity densities ne and nI for the mixture of carbon and neon are shown in Fig. 1, curves 2-5. One can see that ,Q/,T > 0 for practically any temperature at the edge if the concentration ratio nNe/nC , 5. Hence, one can expect the stabilization of RCI by injection of additional impurity and achievement of stable regime with the strongly radiated edge plasmas. The stability of plasmas with few impurity mixtures is examined in the present paper numerically (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Cyclotron Maser Radiation in Space and Laboratory PlasmasCONTRIBUTIONS TO PLASMA PHYSICS, Issue 5-6 2004R. Bingham Abstract One of the best known coherent radio emission mechanisms is the electron cyclotron maser instability. In this article we will demonstrate that electron cyclotron maser emission is directly associated with particular types of charged particle acceleration and propagation in space and laboratory plasmas. These include electron ring distributions, horseshoe or crescent shaped electron distribution functions. Planetary and stellarmagnetospheres are examples of where horseshoe or crescent shaped electron distributions can be found and astrophysical shocks produce ring shaped electron distribution functions. In the laboratory horseshoe or crescent shaped distributions are produced whenever an electron beam propagates into a stronger magnetic field region. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Radiation induced modification of impurity-related point defects in crystalline quartz , a reviewCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2006Harish Bahadur Abstract This article presents a short review of impurity-related point defects in crystalline quartz and their radiation induced modifications. In particular, a discussion has been presented on some of the prominent aluminum related alkali and proton compensated centers. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Does Imiquimod Histologically Rejuvenate Ultraviolet Radiation,Damaged Skin?DERMATOLOGIC SURGERY, Issue 12 2007KATHLEEN SMITH MD BACKGROUND Imiquimod (IMI) 5% is believed by some to result in an improved cosmetic appearance of chronically ultraviolet radiation (UV)-damaged skin. OBJECTIVE The objective was to determine what histologic and immunohistologic changes were present in actinically damaged skin after treatment with IMI. METHODS AND MATERIALS Pre- and posttherapy biopsies of 12 patients with histories of actinic keratoses were evaluated with routine histology and immunohistochemical stains including p53, p63, proliferating cell nuclear antigen (PCNA), c-kit, and Factor XIIIa. RESULTS After IMI therapy there was less compact hyperkeratosis, a more uniform rete ridge pattern with a more ordered proliferation of the epidermis, and a decrease in sun-damaged melanocytes. The papillary dermis showed a more uniform cellularity, and there was increased cellularity within the area of solar elastosis. After therapy, staining for p53, p63, and PCNA was decreased within the epidermis; staining for c-kit was decreased but more uniform in the basal cell; and Factor XIIIa expression was increased within the papillary dermis with a more ordered pattern of staining. CONCLUSION These morphologic and immunohistochemical patterns may explain some of the improvement in overall skin appearance after IMI therapy and may be related to the spectrum of signaling pathways induced by the imidazoquinolines. [source] Mollusk species diversity in the Southeastern Pacific: why are there more species towards the pole?ECOGRAPHY, Issue 2 2003Claudio Valdovinos The most ubiquitous and well recognized diversity pattern at large spatial scales is the latitudinal increase in species richness near the equator and decline towards the poles. Although several exceptions to this pattern have been documented, shallow water mollusks, the most specious group of marine invertebrates, are the epitome of the monotonic decline in species diversity toward higher latitudes along the Pacific and Atlantic coasts of North America. Here we analyze the geographic diversity of 629 mollusk species along the Pacific South American shelf. Our analyses are based on the most complete database of invertebrates assembled for this region of the world, consisting of latitudinal ranges of over 95% of all described mollusks between 10° and 55°S. Along this coast, mollusk diversity did not follow the typical latitudinal trend. The number of species remained constant and relatively low at intermediate latitudes and sharply increased toward higher latitudes, south of 42°S. This trend was explained by changes in shelf area, but not by sea surface temperature, unlike the pattern documented for Northern Hemisphere mollusks. Direct sampling of soft bottom communities along the gradient suggests that regional trends in species richness are produced by increased alpha diversity, and not only by artifacts produced by the increase in sampling area. We hypothesize that increased shelf area south of 42°S, geographic isolation produced by divergence of major oceanic currents, and the existence of refugia during glaciations, enabled species diversification. Radiation could have been limited by narrow continental shelves between 10°,42°. Asymmetries in latitudinal diversity trends between hemispheres show that there is not a single general factor determining large-scale diversity patterns. [source] Long-term Changes in Postnatal Susceptibility to Pilocarpine-induced Seizures in Rats Exposed to Gamma Radiation at Different Stages of Prenatal DevelopmentEPILEPSIA, Issue 10 2003Zuzanna Setkowicz Summary:,Purpose: To determine whether brains irradiated at different stages of prenatal development also have different postnatal susceptibility to seizures evoked by pilocarpine. Methods: Pregnant Wistar rats were exposed to a single 1.0-Gy dose of gamma rays on gestation days 13, 15, 17, or 19 (E13, E15, E17, and E19, respectively). On postnatal day 60, their offspring received i.p. pilocarpine injections to evoke status epilepticus. Behavior of the animals was observed continuously for 6 h after the injection, and motor manifestations of seizure activity were rated, and survival times recorded. After 7-day survival, the animals were killed, and their brains were weighed. Results: The average brain weight of animals exposed to irradiation at earlier prenatal stages (E13 or E15) was significantly lower than that after irradiation on E17 or E19. However, effects of the irradiation on the susceptibility to pilocarpine-induced seizures were quite opposite. The intensity of status epilepticus evoked in rats irradiated on E13 or E15 was significantly lower than that in nonirradiated controls or in those irradiated on E17 or E19. Moreover, after irradiation on E13 or E15, survival of the animals was significantly higher in relation not only to other irradiated groups but also to the controls. Conclusions: The results suggest than the extent of neuronal deficit, even if relatively greater, cannot always lead to higher susceptibility of the dysplastic brain to seizures. Functional consequences of the deficit, even if its magnitude is relatively smaller but involving specific brain areas, appear to be critical for the epileptogenesis. [source] Effects of Ultraviolet Radiation on Locomotion and Orientation in Roughskin Newts (Taricha granulosa)ETHOLOGY, Issue 3 2000Andrew R. Blaustein Environmental changes, including those associated with the atmosphere may significantly affect individual animals and ultimately populations. Ultraviolet (UV) radiation, perhaps increasing due to stratospheric ozone depletion, has been linked to mortality in a number of organisms, including amphibians. The eggs and larvae of certain amphibian species hatch at significantly lower rates when exposed to ambient ultraviolet light. Yet little is known about the sublethal effects of UV radiation. For example, UV radiation may affect specific behaviors of an animal that could alter its ability to survive. To examine if UV radiation affects amphibian behavior, we used roughskin newts (Taricha granulosa) as a model. Newts were exposed to low-level doses of UV in the laboratory and then tested in the field to examine if UV-exposed and control (no UV) newts differed in orientation towards water or in locomotor activity levels. UV-exposed and control newts both exhibited a significant orientation towards water in field tests but there was no significant difference in orientation between treatments. However, UV-exposed newts were significantly more active than control newts. Our results suggest that exposure to short-term low levels of UV radiation alters certain behaviors. Environmentally induced changes in behavior may have significant ecological and evolutionary consequences. [source] Oriented Grain Growth Analyses With In Situ Annealing Experiments Using High Energy Synchrotron RadiationADVANCED ENGINEERING MATERIALS, Issue 3 2010Caterina Elisabetta Tommaseo The development of the recrystallization and annealing textures of Al,Mn alloys with 0.4, 0.7 and 1,wt.-% manganese is analyzed using specific techniques that allow the detection of changes in grain orientation during in situ annealing. In order to investigate the evolution of texture components during annealing, highly rolled samples were annealed from room temperature to 500,°C at a constant heating rate. The advantage of in situ annealing experiments using synchrotron radiation is the detection of grain orientations over time, which allows observation of the development of the recrystallization and annealing textures in a sample. In fact, the recrystallization and annealing textures in the Al,0.4Mn are characterized by an interruption in the detection of most of the grain orientations between 380 and 425,°C and by competition between the cube {001}<100>, {011}<1-33>, {011}<0-11> and rotated-cube {001}<110> grain orientations, where the latter is detected until the end of the experiment. In the Al,0.7Mn sample a competition between the cube {001}<100>, {011}<100>, and rotated cube {001}<110>, {011}<0,11> grain orientations is observed. In the sample with the highest manganese concentration (1,wt.-%) an unhindered grain growth of all possible grain orientations with a high amount of the {011}<0-11> grain orientation is observed. The evolution of the resulting local textures is discussed in terms of preferentially oriented grain growth depending on the temperature and manganese concentration. [source] Principles of Highly Resolved Determination of Texture and Microstructure using High-Energy Synchrotron Radiation,ADVANCED ENGINEERING MATERIALS, Issue 6 2009Helmut Klein Abstract Diffraction imaging with hard X-rays (high-energy synchrotron radiation) using the detector sweeping techniques allows measurement of the texture and microstructure of polycrystalline materials with high orientation- and location-resolution. These techniques provide continuous two-dimensional images of different sections and projections of the six-dimensional "orientation-location" space. For the high orientation resolution case, it is possible to measure the orientation and location coordinates of up to 105 individual grains simultaneously. From these parameters, the grain size and shape can also be obtained, yielding the complete orientation stereology of the polycrystalline aggregate, which is required for its complete characterization. For the high location resolution case, the intensity at any point of the diagrams corresponds to a pole density as a function of the orientation-location space. [source] Radiation Grafted Membranes for Polymer Electrolyte Fuel Cells,FUEL CELLS, Issue 3 2005L. Gubler Abstract The cost of polymer electrolyte fuel cell (PEFC) components is crucial to the commercial viability of the technology. Proton exchange membranes fabricated via the method of radiation grafting offer a cost-competitive option, because starting materials are inexpensive commodity products and the preparation procedure is based on established industrial processes. Radiation grafted membranes have been used with commercial success in membrane separation technology. This review focuses on the application of radiation grafted membranes in fuel cells, in particular the identification of fuel cell relevant membrane properties, aspects of membrane electrode assembly (MEA) fabrication, electrochemical performance and durability obtained in cell or stack tests, and investigation of failure modes and post mortem analysis. The application in hydrogen and methanol fuelled cells is treated separately. Optimized styrene,/,crosslinker grafted and sulfonated membranes show performance comparable to perfluorinated membranes. Some properties, such as methanol permeability, can be tailored to be superior. Durability of several thousand hours at practical operating conditions has been demonstrated. Alternative styrene derived monomers with higher chemical stability offer the prospect of enhanced durability or higher operating temperature. [source] Radiation synovectomy by 188Re-Sulfide in haemophilic synovitisHAEMOPHILIA, Issue 5 2004P. Li Summary., Radiation synovectomy is a safe and effective treatment for chronic haemophilic synovitis causing recurrent haemarthroses. This study reports results of 29 188Re-sulfide radiation synovectomies in knee joint with a follow-up 18 months. Using the absorbed dose factor, three groups of radioactivity dose (555 MBq, 687 MBq and 917 MBq) were used according to the synovium thickness that measured by MRI. Excellent and good results (haemarthrosis reduction from 75 to 100%) were obtained in 71% of cases at 18 months. Comparison of the results, no significant difference was found among the radioactivity dose groups. Radiation was well contained within the knee. There were no observed or identified complications including the detectable harm to the articular cartilage, as shown by MRI. [source] Design of A Soft X-ray Source with Periodic Microstructure Using Resonance Transition Radiation for Tabletop SynchrotronIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 3 2008Koji Sugano Member Abstract A soft X-ray source with a periodic aluminum multilayer structure with vacuum layers in between for tabletop synchrotrons with low-energy electrons was designed, and the dependence of radiation performance on structural parameters was clarified using a theoretical calculation of the resonance transition radiation. A photon density of 1 keV pr incident electron was calculated by optimizing the thickness of the aluminum and vacuum layers. Furthermore, the designed structure was fabricated by a microfabrication technique. The effects of dimensional error on the photon density are discussed on the basis of the calculated results and the prototype structure of a 6-MeV synchrotron. It is clarified that dimensional errors of 1.5% in Al layers and of plus or minus a few dozen nanometers in the vacuum layers are negligible in obtaining a photon density of more than 90% of the maximum value. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Erectile dysfunction after surgical treatment,INTERNATIONAL JOURNAL OF ANDROLOGY, Issue 3 2003Vincenzo Mirone Summary Erectile dysfunction is a recognized complication of prostate and bladder radical surgery, although there is significant variation in the reported risk, much of this variability is related to the retrospective nature of most previous studies. Undoubtedly, the quality of life of bladder and prostate cancer patients would be much improved if both normal micturition and potency are preserved, which is the subject of this article. Quality of life studies can delineate sexual function after radical prostatectomy, including the use of sexual aids. Penile erection is a neurovascular event modulated by neurotransmitters and hormonal status. The penis is innervated by autonomic and somatic nerves. Both surgery and radiation therapy appear to affect such a mechanism. Radiation is thought to produce Erectile Dysfunction (ED) by accelerating microvascular angiopathy causing cavernosal fibrosis or stenosis of the pelvic arteries and by accelerating existing arteriosclerosis, leading to vascular impotence. Years may elapse before clinically significant ED occurs. Criteria that influence recovery of erections after surgery include younger patient age, stronger erections before operation, preservation of the neurovascular bundles, and attention to fine details in the surgical technique. Recovery of erections occurs in 68% of preoperatively potent men treated with bilateral nerve-sparing surgery and in 47% of those treated with unilateral nerve-sparing surgery. [source] Suppression of testosterone stimulates recovery of spermatogenesis after cancer treatmentINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 3 2003Marvin L. Meistrich Summary It is important to develop methods to prevent or reverse the infertility caused by chemotherapy or radiation therapy for cancer in men. Radiation and some chemotherapeutic agents kill spermatogonial stem cells, but we have shown that these cells survive in rats, although they are unable to differentiate. There is evidence that this phenomenon also occurs in men. The block to spermatogonial differentiation in rats is caused by some unknown change, either in the spermatogonia or the somatic elements of the testis, such that testosterone inhibits spermatogonial differentiation. In the rat, the spermatogenesis and fertility lost following treatment with radiation or some chemotherapeutic agents can be restored by suppressing testosterone with gonadotropin releasing hormone (GnRH) agonists or antagonists, either before or after the cytotoxic insult. The applicability of this procedure to humans is still unknown. Some anticancer regimens may kill all the stem cells, in which case the only option would be spermatogonial transplantation. However, in some cases stem cells survive and there is one report of stimulation of recovery of spermatogenesis with hormonal treatment. Clinical trials should focus on treating patients with hormones during or soon after anticancer treatment. The hormone regimen should involve suppression of testosterone production with minimum androgen supplementation used to improve the diminished libido. [source] Radiation-induced cathepsin S is involved in radioresistanceINTERNATIONAL JOURNAL OF CANCER, Issue 8 2009Haeng Ran Seo Abstract Previous studies have suggested that the production of cathepsin S (CatS), a cysteine protease, was specifically induced in radiation-induced rat mammary tumors. In this study, we further investigate the mechanism by which CatS is induced by radiation and its function. Radiation induced production of CatS at both the mRNA and protein level, and increased its protease activity. In addition, these radiation induced changes occurred in a dose and time-dependent fashion. Agents such as bleomycin, As2O3 and H2O2, which produce reactive oxygen species (ROS), also induced CatS expression; however, other agents that damage DNA such as taxol and cisplatin did not. Additionally, treatment of the cells with the ROS scavengers, N-acetylcysteine and catalase, inhibited the radiation induced CatS expression. Furthermore, radiation-induced ROS was also involved in IFN-, production, which was responsible for radiation-mediated CatS expression. Moreover, electrophoretic mobility shift assay (EMSA) data obtained using an IFN-stimulated response element (ISRE) oligonucleotide revealed that IFN regulatory factor-1 (IRF1) was the critical transcriptional mediator of IFN-,-dependent CatS production after radiation. Finally, CatS overespression was found to induce radioresistance; however, knockdown of CatS resulted in the suppression of radioresistance. Taken together, the results of this study indicate that radiation induced CatS expression via ROS-IFN-, pathways, and that this increased expression may be involved in radioresistance. © 2008 Wiley-Liss, Inc. [source] Radiation-induced HIF-1, cell survival pathway is inhibited by soy isoflavones in prostate cancer cellsINTERNATIONAL JOURNAL OF CANCER, Issue 7 2009Vinita Singh-Gupta Abstract We previously showed that treatment of prostate cancer cells with soy isoflavones and radiation resulted in greater cell killing in vitro, and caused downregulation of NF-,B and APE1/Ref-1. APE1/Ref-1 functions as a redox activator of transcription factors, including NF-,B and HIF-1,. These molecules are upregulated by radiation and implicated in radioresistance of cancer cells. We extended our studies to investigate the role of HIF-1, survival pathway and its upstream Src and STAT3 molecules in isoflavones and radiation interaction. Radiation induced phosphorylation of Src and STAT3 leading to induction of HIF-1,. Genistein, daidzein or a mixture of soy isoflavones did not activate this pathway. These data were observed both in PC-3 (AR-) and C4-2B (AR+) androgen-independent cell lines. Pretreatment with isoflavones inhibited Src/STAT3/HIF-1, activation by radiation and nuclear translocation of HIF-1,. These findings correlated with decreased expression of APE1/Ref-1 and DNA binding activity of HIF-1, and NF-,B. In APE1/Ref-1 cDNA transfected cells, radiation caused a greater increase in HIF-1, and NF-,B activities but this effect was inhibited by pretreatment with soy prior to radiation. Transfection experiments indicate that APE1/Ref-1 inhibition by isoflavones impairs the radiation-induced transcription activity of NF-,B and HIF-1,. This mechanism could result in the inhibition of genes essential for tumor growth and angiogenesis, as demonstrated by inhibition of VEGF production and HUVECs tube formation. Our novel findings suggest that the increased responsiveness to radiation mediated by soy isoflavones could be due to pleiotropic effects of isoflavones blocking cell survival pathways induced by radiation including Src/STAT3/HIF-1,, APE1/Ref-1 and NF-,B. © 2008 Wiley-Liss, Inc. [source] Induced and repressed genes after irradiation sensitizing by pentoxyphylline,INTERNATIONAL JOURNAL OF CANCER, Issue 6 2007Waldemar Waldeck Abstract Aim in cancer therapy is to increase the therapeutic ratio eliminating the disease while minimizing toxicity to normal tissues. Radiation therapy is a main component in targeting cancer. Radiosensitizing agents like pentoxyphylline (PTX) have been evaluated to improve radiotherapy. Commonly, cells respond to radiation by the activation of specific early and late response genes as well as by inhibition of genes, which are expressed under normal conditions. A display of the genetic distinctions at the level of transcription is given here to characterize the molecular events underlying the radiosensitizing mechanisms. The method of suppression subtractive hybridization allows the visualization of both induced and repressed genes in irradiated cells compared with cells sensitized immediately after irradiation. The genes were isolated by cDNA-cloning, differential analysis and sequence similarity search. Genes involved in protein synthesis, metabolism, proteolysis and transcriptional regulation were detected. It is important that genes like KIAA280, which were only known as unidentified EST sequences before without function, but inaccessible by array technology were recovered as functional genes. Database searches for PTX-induced genes detected a human mRNA completely unknown. In case of suppressed genes, we detected several mRNAs; one thereof shows homology to a hypothetical protein possibly involved in signal transduction. A further mRNA encodes the protein BM036 supposed to associate with the E2F transcription factor. A hypothetical protein H41 was detected, which may repress the Her-2/neu receptor influencing breast cancer, gliomas and prostate tumors. Radiation combined with PTX may lead to a better prognosis by down regulation of the Her-2/neu, which will be proven by clinical studies in the near future. © 2006 Wiley-Liss, Inc. [source] An update of EU legislation (Directives and Regulations) on food-related issues (Safety, Hygiene, Packaging, Technology, GMOs, Additives, Radiation, Labelling): presentation and commentsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2005Ioannis S. Arvanitoyannis Summary This review aims at providing an update of the current European Union (EU) Regulations and Directives on food-related issues. Initially, a brief presentation of EU legislation in terms of structure (horizontal, vertical) was attempted. EU Regulations and Directives were classified into the following categories: food safety (Hazard Analysis Critical Control Points, pesticides, radioactive, hormones, contaminants, freezing , ionisation, food additives, flavourings, packaging), genetically modified organisms, food quality, labelling, food products of plant or animal origin, imports from third countries. Apart from a synoptical presentation of all laws related to the above-mentioned topics, proper tables were compiled where the main points of each law are cited in conjunction with its effect on previous laws (repeal, modification, amendments, replacement). In such a way the reader can rapidly acquire a first approach to the topic of his interest. [source] Sensitivity of Crops to Increased Ultraviolet Radiation in Northern Growing ConditionsJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2002K. Hakala Crops growing at high latitudes are adapted to low intensities of solar ultraviolet B radiation (UV-B). As a result of destruction of stratospheric ozone layer especially at the Polar Regions of the globe, the intensity of UV-B is projected to increase at high latitudes. In order to find out the consequences of increased UV-B on crops, the sensitivity of different varieties of barley, wheat, oats, clover, timothy, meadow fescue, tall fescue and potato was tested in Jokioinen, Finland. The experiment was conducted in the field, under natural light, with a continuous 30 % increase in UV-B. Both increased UV-B and the control with slightly increased UV-A radiation affected the number of lateral shoots in cereals, and the specific leaf area and the content of phenolic substances in grasses. The effects varied according to plant variety and time of growing season. However, no visible damage, nor changes in biomass and yield production were found in any of the crops. Long-term effects on, e.g. genetic stability and germination of crop seed remain to be studied. Empfindlichkeit von Kulturpflanzenbeständen gegenüber einer Erhöhung der ultravioletten Einstrahlung unter nördlichen Wachstumsbedingungen Kulturpflanzenbestände, die unter hohen Breitengraden wachsen, sind an geringe Intensitäten der solaren ultravioletten B Einstrahlung (UV-B) angepasst. Aufgrund der Destruktion der Stratosphäre, insbesondere der Ozonschicht, im Bereich der polaren Gebiete der Erde, ist eine zunehmende Intensität der UV-B Strahlung in hohen Breitengraden festzustellen. Um die Konsequenzen einer Erhöhung von UV-B auf Kulturpflanzenbestände zu bestimmen, wurde die Empfindlichkeit unterschiedlicher Arten wie Gerste, Weizen, Hafer, Klee, Wiesenlieschgras, Wiesenschwingel, Rohrschwingel und Kartoffel in Jokioinen, Finnland, untersucht. Das Experiment wurde im Felde durchgeführt unter natürlichen Lichtbedingungen mit einer kontinuierlichen Zunahme von 30 % für UV-B. Sowohl eine Erhöhung der UV-B als auch die Kontrolle mit leicht erhöhten UV-B Strahlungen beeinflussten die Anzahl der Nebenwurzeln bei den Getreidepflanzen und die spezifische Blattfläche sowie den Gehalt an phenolischen Substanzen bei den Gräsern. Die Wirkungen variierten entsprechend der Pflanzenvarietät und der Anbauzeit. Allerdings wurden keine erkennbare Schädigungen noch Änderungen in der Biomasse und in der Ertragsproduktion bei einer der untersuchten Pflanzenbestände gefunden. Langzeitwirkungen auf die genetische bedingte Stabilität und Keimung der Kulturpflanzen sollte weiterhin untersucht werden. [source] Radiation of Atlantic goldcrests Regulus regulus spp.: evidence of a new taxon from the Canary IslandsJOURNAL OF AVIAN BIOLOGY, Issue 4 2006Martin Päckert Phylogenetic relationships between goldcrest populations from the Atlantic Islands (Azores and Canary Islands) were investigated by two molecular markers (mitochondrial control region and cytochrome b sequences), and partly by morphology and territorial song. The Azorean goldcrest populations are closely related to European nominate R. r. regulus. Most probably, the Azores were colonized by goldcrests in a single late-pleistocene invasion, while colonization of the Canary Islands presumably occurred in two steps: An early invasion to Tenerife and La Gomera 1.9,2.3 million years (my) ago and a more recent one to El Hierro and La Palma 1.3,1.8 my ago. Distribution of haplotypes on the Azores suggests a division of R. r. azoricus on São Miguel into an eastern population with close affinities to R. r. sanctaemariae and a western population belonging to the lineage of R. r. inermis on the central and western island group. The Canarian populations are genetically substructured into a northeastern group embracing Tenerife and La Gomera and a second, southwestern group including El Hierro and La Palma. Genetic distances between members of the two Canarian clades range at 3.1,3.4% (TrN distance, control region and cytochrome b). Differentiation between the two groups is also supported by morphology and by territorial song. Substitution rate estimates for the both genes range at approximately the same values of 0.0031 and 0.0044 substitutions per site and lineage per my which roughly corresponds 0.61,0.83% divergence between Regulus lineages per my. Highest local rates occur in island clades of the Azorean and the Canarian population and in R. r. japonensis from the Russian Far East and Japan. However, a general acceleration of a molecular clock in island populations is not evident from the Regulus data set due to extremely low local rate estimates in the Canarian clade of Tenerife and La Gomera. As a taxonomic consequence of the marked differentiation of the two Canarian goldcrest clades the populations from El Hierro and La Palma are described as a taxon new to science and are named Regulus regulus ellenthalerae n. ssp. [source] Retention of Quality and Nutritional Value of 13 Fresh-Cut Vegetables Treated with Low-Dose RadiationJOURNAL OF FOOD SCIENCE, Issue 7 2008X. Fan ABSTRACT:, Improving the microbial safety while maintaining quality of fresh fruits and vegetables will increase consumer confidence in fresh produce. This study was conducted to investigate the effects of irradiation at 1 kGy, a dose that potentially inactivates E. coli O157:H7 by 5 logs, on the quality of 13 common fresh-cut vegetables: iceberg, romaine, green and red leaf lettuce, spinach, tomato, cilantro, parsley, green onion, carrot, broccoli, red cabbage, and celery. The results showed that the appearance of irradiated samples was similar to the nonirradiated ones except that irradiated carrots, celery, cilantro, and green onions had higher appearance scores than corresponding nonirradiated vegetables. There was no difference in the instrumental texture between irradiated samples and nonirradiated ones. The aroma of several irradiated vegetables was significantly better than controls after 14-d storage, because these control samples decayed or senesced. The 1 kGy irradiation did not affect vitamin C content of most vegetables; however, irradiated green and red leaf lettuce had 24% to 53% lower vitamin C contents than the controls. Our results suggest that most fresh-cut fruits and vegetables tested can tolerate up to 1 kGy irradiation without significant losses in any of the quality attributes. [source] Nalidixic Acid Resistance Increases Sensitivity of Escherichia coli O157:H7 to Ionizing Radiation in Solution and on Green Leaf LettuceJOURNAL OF FOOD SCIENCE, Issue 2 2005Brendan A. Niemira ABSTRACT: Nalidixic acid resistance has been used as a selective marker for studies of pathogen-inoculated fruits and vegetables. Three nalidixic acid-sensitive outbreak strains of Escherichia coli O157:H7 were used to generate mutants resistant to nalidixic acid (NalR, 50 ,g/mL) by successive culturing and selection in nalidixic acid-amended broth. The resistance to ionizing radiation of the parent and NalR strains was determined (a) in a phosphate buffer solution and (b) on green leaf lettuce. The NalR strains of each of the 3 isolates were significantly (P < 0.05) more sensitive to ionizing radiation than the nalidixic acid-sensitive (NalS) parent strains in both systems. D10 values (the amount of ionizing radiation required to achieve 1 log10 reduction) determined in buffer for the parent strains ranged from 0.18 to 0.33 kGy, whereas for the NalR strains, D10 were approximately 0.10 kGy, a reduction of up to 69%. When evaluated on green leaf lettuce, the D10 for the NalS strains was approximately 0.18 kGy as opposed to 0.10 to 0.12 kGy for the NalR strains, a reduction of up to 45%. The D10 values obtained on lettuce were significantly different than those obtained in buffer for 4 of the 6 isolates examined. The magnitude of the increase in radiation sensitivity resulting from resistance to nalidixic acid varied among the strains tested and also varied depending on the suspending medium. These results suggest that the use of nalidixic acid resistance as a selective marker may result in significant overestimates of the antimicrobial efficacy of ionizing radiation against E. coli O157:H7. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||