Age and metabolic risk factors associated with oxidatively damaged DNA in human peripheral blood mononuclear cells

DEFF Research Database (Denmark)

Løhr, Mille; Jensen, Annie; Eriksen, Louise

2015-01-01

Aging is associated with oxidative stress-generated damage to DNA and this could be related to metabolic disturbances. This study investigated the association between levels of oxidatively damaged DNA in peripheral blood mononuclear cells (PBMCs) and metabolic risk factors in 1,019 subjects, aged...... 18-93 years. DNA damage was analyzed as strand breaks by the comet assay and levels of formamidopyrimidine (FPG-) and human 8-oxoguanine DNA glycosylase 1 (hOGG1)-sensitive sites There was an association between age and levels of FPG-sensitive sites for women, but not for men. The same tendency......, cholesterol and glycosylated hemoglobin (HbA1c). In the group of men, there were significant positive associations between alcohol intake, HbA1c and FPG-sensitive sites in multivariate analysis. The levels of metabolic risk factors were positively associated with age, yet only few subjects fulfilled all...

Gamma non-ionizing energy loss: Comparison with the damage factor in silicon devices

Science.gov (United States)

El Allam, E.; Inguimbert, C.; Meulenberg, A.; Jorio, A.; Zorkani, I.

2018-03-01

The concept of non-ionizing energy loss (NIEL) has been demonstrated to be a successful approach to describe the displacement damage effects in silicon materials and devices. However, some discrepancies exist in the literature between experimental damage factors and theoretical NIELs. 60Co gamma rays having a low NIEL are an interesting particle source that can be used to validate the NIEL scaling approach. This paper presents different 60Co gamma ray NIEL values for silicon targets. They are compared with the radiation-induced increase in the thermal generation rate of carriers per unit fluence. The differences between the different models, including one using molecular dynamics, are discussed.

Human recombinant factor VIIa may improve heat intolerance in mice by attenuating hypothalamic neuronal apoptosis and damage.

Science.gov (United States)

Hsu, Chuan-Chih; Chen, Sheng-Hsien; Lin, Cheng-Hsien; Yung, Ming-Chi

2014-10-01

Intolerance to heat exposure is believed to be associated with hypothalamo-pituitary-adrenocortical (HPA) axis impairment [reflected by decreases in blood concentrations of both adrenocorticotrophic-hormone (ACTH) and corticosterone]. The purpose of this study was to determine the effect of human recombinant factor VIIa (rfVIIa) on heat intolerance, HPA axis impairment, and hypothalamic inflammation, ischemic and oxidative damage, and apoptosis in mice under heat stress. Immediately after heat stress (41.2 °C for 1 h), mice were treated with vehicle (1 mL/kg of body weight) or rfVIIa (65-270 µg/kg of body weight) and then returned to room temperature (26 °C). Mice still alive on day 4 of heat exposure were considered survivors. Cellular ischemia markers (e.g., glutamate, lactate-to-pyruvate ratio), oxidative damage markers (e.g., nitric oxide metabolite, hydroxyl radials), and pro-inflammatory cytokines (e.g., interleukin-6, interleukin-1β, tumor necrosis factor-α) in hypothalamus were determined. In addition, blood concentrations of both ACTH and corticosterone were measured. Hypothalamic cell damage was assessed by determing the neuronal damage scores, whereas the hypothalamic cell apoptosis was determined by assessing the numbers of cells stained with terminal deoxynucleotidyl transferase-mediated αUTP nick-end labeling, caspase-3-positive cells, and platelet endothelial cell adhesion molecula-1-positive cells in hypothalamus. Compared with vehicle-treated heated mice, rfVIIa-treated heated mice had significantly higher fractional survival (8/10 vs 1/10), lesser thermoregulatory deficit (34.1 vs 24.8 °C), lesser extents of ischemic, oxidative, and inflammatory markers in hypothalamus, lesser neuronal damage scores and apoptosis in hypothalamus, and lesser HPA axis impairment. Human recombinant factor VIIa appears to exert a protective effect against heatstroke by attenuating hypothalamic cell apoptosis (due to ischemic, inflammatory, and oxidative damage

An Investigation of Damage Factors in Industrial Scale of Light-Weight Bricks Production

Directory of Open Access Journals (Sweden)

Dwi Wulandari Kiki

2017-01-01

Full Text Available A damage case of light weight brick’s production approximately at 6-7% of total production was found daily in one industry in East Jawa, Indonesia. The physical damage of product always occured. This paper investigates some factors that affect the lost in laboratory analysis. The analysis includes the chemical analysis of raw materials, reactivity of pozzolanic materials, and observation of strength based upon the position of light-weight bricks during autoclaving process. In addition, fly ash is introduced as mineral additive as one of the alternatives to improve the product’s quality. It is also concluded that grinding the silica sands particles is the optimum way to improve the quality, but the adding class F of fly ash to five percent in mixture is the most effective solution. Furthermore, maintaining quality of raw materials, curing process, and maintaining the machine will either reduce the product damage that occurred during the fabrication process in industry.

Contributing and Damaging Factors Related to the Psychological Capital of Teachers: A Qualitative Analysis

Science.gov (United States)

Çimen, Ismail; Özgan, Habib

2018-01-01

Over the last two decades, psychological capital has gained prominence in the literature on positive organisational behaviour. However, further investigation is still needed in relation to this issue, particularly in the context of educational organisations. Accordingly, this study aimed to examine the contributing and damaging factors relating to…

Crop Damage: The Hail Size Factor.

Science.gov (United States)

Sánchez, J. L.; Fraile, R.; de La Madrid, J. L.; de La Fuente, M. T.; Rodríguez, P.; Castro, A.

1996-09-01

Between 1986 and 1992 a research project was developed and carried out on hail climatology and the economic repercussions of hail on agriculture in León (northwestern Spain). A target area with an extent of 6825 km2 was defined, within which a network of meteorological observers was established at an average density of 1 per 17 km2. A network of 250 hailpads installed in a grid formation was also laid out over an area of 1000 km2 inside the target area. The frequent occurrence of hailfalls—122 hail days over seven consecutive summers—provided a detailed database and allowed several climatological studies to be made. Crop damage was also closely monitored and quantified. Barley and wheat were selected as crops on which to base an analysis of the relationship between hailfall characteristics and crop damage. As the resistance of plants to hailstones is held to vary according to their physiological state, four different stages of plant growth were defined, beginning with the formation of grain heads.An important conclusion was drawn: the dispersion of percentages of damage always covers the possible variations in resistance caused by the physiological state of the plants. As a result, using only minimal information about hailfall characteristics—namely, the initial reports of observers regarding hailstone size—a working statistical model has successfully been constructed to predict losses to barley and wheat, using data provided by the León hail project.

Protective Role of Nuclear Factor E2-Related Factor 2 against Acute Oxidative Stress-Induced Pancreatic β-Cell Damage

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Jingqi Fu

2015-01-01

Full Text Available Oxidative stress is implicated in the pathogenesis of pancreatic β-cell dysfunction that occurs in both type 1 and type 2 diabetes. Nuclear factor E2-related factor 2 (NRF2 is a master regulator in the cellular adaptive response to oxidative stress. The present study found that MIN6 β-cells with stable knockdown of Nrf2 (Nrf2-KD and islets isolated from Nrf2-knockout mice expressed substantially reduced levels of antioxidant enzymes in response to a variety of stressors. In scramble MIN6 cells or wild-type islets, acute exposure to oxidative stressors, including hydrogen peroxide (H2O2 and S-nitroso-N-acetylpenicillamine, resulted in cell damage as determined by decrease in cell viability, reduced ATP content, morphology changes of islets, and/or alterations of apoptotic biomarkers in a concentration- and/or time-dependent manner. In contrast, silencing of Nrf2 sensitized MIN6 cells or islets to the damage. In addition, pretreatment of MIN6 β-cells with NRF2 activators, including CDDO-Im, dimethyl fumarate (DMF, and tert-butylhydroquinone (tBHQ, protected the cells from high levels of H2O2-induced cell damage. Given that reactive oxygen species (ROS are involved in regulating glucose-stimulated insulin secretion (GSIS and persistent activation of NRF2 blunts glucose-triggered ROS signaling and GSIS, the present study highlights the distinct roles that NRF2 may play in pancreatic β-cell dysfunction that occurs in different stages of diabetes.

Gc-protein-derived macrophage activating factor counteracts the neuronal damage induced by oxaliplatin.

Science.gov (United States)

Morucci, Gabriele; Branca, Jacopo J V; Gulisano, Massimo; Ruggiero, Marco; Paternostro, Ferdinando; Pacini, Alessandra; Di Cesare Mannelli, Lorenzo; Pacini, Stefania

2015-02-01

Oxaliplatin-based regimens are effective in metastasized advanced cancers. However, a major limitation to their widespread use is represented by neurotoxicity that leads to peripheral neuropathy. In this study we evaluated the roles of a proven immunotherapeutic agent [Gc-protein-derived macrophage activating factor (GcMAF)] in preventing or decreasing oxaliplatin-induced neuronal damage and in modulating microglia activation following oxaliplatin-induced damage. The effects of oxaliplatin and of a commercially available formula of GcMAF [oleic acid-GcMAF (OA-GcMAF)] were studied in human neurons (SH-SY5Y cells) and in human microglial cells (C13NJ). Cell density, morphology and viability, as well as production of cAMP and expression of vascular endothelial growth factor (VEGF), markers of neuron regeneration [neuromodulin or growth associated protein-43 (Gap-43)] and markers of microglia activation [ionized calcium binding adaptor molecule 1 (Iba1) and B7-2], were determined. OA-GcMAF reverted the damage inflicted by oxaliplatin on human neurons and preserved their viability. The neuroprotective effect was accompanied by increased intracellular cAMP production, as well as by increased expression of VEGF and neuromodulin. OA-GcMAF did not revert the effects of oxaliplatin on microglial cell viability. However, it increased microglial activation following oxaliplatin-induced damage, resulting in an increased expression of the markers Iba1 and B7-2 without any concomitant increase in cell number. When neurons and microglial cells were co-cultured, the presence of OA-GcMAF significantly counteracted the toxic effects of oxaliplatin. Our results demonstrate that OA-GcMAF, already used in the immunotherapy of advanced cancers, may significantly contribute to neutralizing the neurotoxicity induced by oxaliplatin, at the same time possibly concurring to an integrated anticancer effect. The association between these two powerful anticancer molecules would probably produce

Red-cockaded woodpecker cavity-tree damage by Hurricane Rita: an evaluation of contributing factors

Science.gov (United States)

Ben Bainbridge; Kristen A. Baum; Daniel Saenz; Cory K. Adams

2011-01-01

Picoides borealis (Red-cockaded Woodpecker) is an endangered species inhabiting pine savannas of the southeastern United States. Because the intensity of hurricanes striking the southeastern United States is likely to increase as global temperatures rise, it is important to identify factors contributing to hurricane damage to Red-cockaded Woodpecker cavity-trees. Our...

Cerebral Damage May Be the Primary Risk Factor for Visual Impairment in Preschool Children Born Extremely Premature

DEFF Research Database (Denmark)

Slidsborg, Carina; Bangsgaard, Regitze; Fledelius, Hans Callø

2012-01-01

OBJECTIVES To investigate the importance of cerebral damage and retinopathy of prematurity (ROP) for visual impairment in preschool children born extremely premature and to determine the primary risk factor of the two. METHODS A clinical follow-up study of a Danish national cohort of children born......, 3.0-25.2; P visual impairment in children born extremely premature, and cerebral damage may be the primary risk...... participants were identified through the National Birth Register and invited to participate in a clinical examination. The children were evaluated with regard to visual acuity, foveal sequelae, and maximum ROP stage and the presence of global developmental deficits (an indicator for cerebral damage...

Fatigue damage estimation using irregularity factor. First report, irregularity factor calculations for narrow and broadband random time histories

Science.gov (United States)

Susuki, I.

1981-11-01

The results of an analysis of the irregularity factors of stationary and Gaussian random processes which are generated by filtering the output of a pure or a band-limited white noise are presented. An ideal band pass filter, a trapezoidal filter, and a Butterworth type band pass filter were examined. It was found that the values of the irregularity factors were approximately equal among these filters if only the end-slopes were the same rates. As the band width of filters increases, irregularity factors increase monotonically and approach the respective constant values depending on the end-slopes. This implies that the noise characteristics relevant to the fatigue damage such as statistical aspects of the height of the rise and fall or the distribution of the peak values are not changed for a broad band random time history. It was also found that the effect of band limitation of input white noise on irregularity factors is negligibly small.

Continuum modeling of post-implantation damage and the effective plus factor in crystalline silicon at room temperature

International Nuclear Information System (INIS)

Chan, H.Y.; Srinivasan, M.P.; Benistant, F.; Mok, K.R.; Chan, Lap; Jin, H.M.

2006-01-01

The role of computer simulation in predicting intrinsic diffusion effects is amplified with the shrinkage of MOS devices. In this work, post-implant damage distributions are obtained from atomistic Monte Carlo (MC) simulations. Based on diffusion-limiting kinetics, the evolution of the damage at room temperature with time is studied. It is shown that evolution of the point defects follow the Ostwald ripening process, where larger defect clusters grow at the expense of smaller ones. A qualitative study of the effective plus factor is also conducted, taking into account various clustering and recombination processes. Clustering is found to significantly affect the remaining amount of damage, which in turn affects subsequent diffusion processes

Diet-Induced Weight Loss Reduces DNA Damage and Cardiometabolic Risk Factors in Overweight/Obese Women with Polycystic Ovary Syndrome.

Science.gov (United States)

Soares, Nayara Pereira; Santos, Ana Celly Souza dos; Costa, Eduardo Caldas; Azevedo, George Dantas; Damasceno, Débora Cristina; Fayh, Ana Paula Trussardi; Lemos, Telma Maria Araújo Moura

2016-01-01

We aimed to investigate the impact of following a diet to induce weight loss (500 kcal deficit per day) over DNA damage and cardiometabolic risk factors in women with overweight/obesity diagnosed with polycystic ovary syndrome (PCOS). A study was conducted in Natal, RN, Brazil selecting overweight/obese (body mass index ≥25 and weight loss, decreased sexual hormone and cardiometabolic markers such as insulin, homeostasis model assessment of insulin resistance and low-density lipoprotein cholesterol were verified In the multivariate regression analysis, quantitative insulin sensitivity check index and progesterone were responsible for the variation markers in DNA damage before the diet, losing its influence upon diet. DNA damage and the impact of cardiometabolic risk factors decreased after the intervention in women with PCOS, indicating the relevance of a nutritional approach in this group of patients. © 2016 S. Karger AG, Basel.

FOXO3 Transcription Factor Is Essential for Protecting Hematopoietic Stem and Progenitor Cells from Oxidative DNA Damage.

Science.gov (United States)

Bigarella, Carolina L; Li, Jianfeng; Rimmelé, Pauline; Liang, Raymond; Sobol, Robert W; Ghaffari, Saghi

2017-02-17

Accumulation of damaged DNA in hematopoietic stem cells (HSC) is associated with chromosomal abnormalities, genomic instability, and HSC aging and might promote hematological malignancies with age. Despite this, the regulatory pathways implicated in the HSC DNA damage response have not been fully elucidated. One of the sources of DNA damage is reactive oxygen species (ROS) generated by both exogenous and endogenous insults. Balancing ROS levels in HSC requires FOXO3, which is an essential transcription factor for HSC maintenance implicated in HSC aging. Elevated ROS levels result in defective Foxo3 -/- HSC cycling, among many other deficiencies. Here, we show that loss of FOXO3 leads to the accumulation of DNA damage in primitive hematopoietic stem and progenitor cells (HSPC), associated specifically with reduced expression of genes implicated in the repair of oxidative DNA damage. We provide further evidence that Foxo3 -/- HSPC are defective in DNA damage repair. Specifically, we show that the base excision repair pathway, the main pathway utilized for the repair of oxidative DNA damage, is compromised in Foxo3 -/- primitive hematopoietic cells. Treating mice in vivo with N -acetylcysteine reduces ROS levels, rescues HSC cycling defects, and partially mitigates HSPC DNA damage. These results indicate that DNA damage accrued as a result of elevated ROS in Foxo3 -/- mutant HSPC is at least partially reversible. Collectively, our findings suggest that FOXO3 serves as a protector of HSC genomic stability and health. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Methylmercury Causes Blood-Brain Barrier Damage in Rats via Upregulation of Vascular Endothelial Growth Factor Expression.

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Tetsuya Takahashi

Full Text Available Clinical manifestations of methylmercury (MeHg intoxication include cerebellar ataxia, concentric constriction of visual fields, and sensory and auditory disturbances. The symptoms depend on the site of MeHg damage, such as the cerebellum and occipital lobes. However, the underlying mechanism of MeHg-induced tissue vulnerability remains to be elucidated. In the present study, we used a rat model of subacute MeHg intoxication to investigate possible MeHg-induced blood-brain barrier (BBB damage. The model was established by exposing the rats to 20-ppm MeHg for up to 4 weeks; the rats exhibited severe cerebellar pathological changes, although there were no significant differences in mercury content among the different brain regions. BBB damage in the cerebellum after MeHg exposure was confirmed based on extravasation of endogenous immunoglobulin G (IgG and decreased expression of rat endothelial cell antigen-1. Furthermore, expression of vascular endothelial growth factor (VEGF, a potent angiogenic growth factor, increased markedly in the cerebellum and mildly in the occipital lobe following MeHg exposure. VEGF expression was detected mainly in astrocytes of the BBB. Intravenous administration of anti-VEGF neutralizing antibody mildly reduced the rate of hind-limb crossing signs observed in MeHg-exposed rats. In conclusion, we demonstrated for the first time that MeHg induces BBB damage via upregulation of VEGF expression at the BBB in vivo. Further studies are required in order to determine whether treatment targeted at VEGF can ameliorate MeHg-induced toxicity.

Benfotiamine alleviates diabetes-induced cerebral oxidative damage independent of advanced glycation end-product, tissue factor and TNF-alpha.

Science.gov (United States)

Wu, Shan; Ren, Jun

2006-02-13

Diabetes mellitus leads to thiamine deficiency and multiple organ damage including diabetic neuropathy. This study was designed to examine the effect of benfotiamine, a lipophilic derivative of thiamine, on streptozotocin (STZ)-induced cerebral oxidative stress. Adult male FVB mice were made diabetic with a single injection of STZ (200 mg/kg, i.p.). Fourteen days later, control and diabetic (fasting blood glucose >13.9 mM) mice received benfotiamine (100 mg/kg/day, i.p.) for 14 days. Oxidative stress and protein damage were evaluated by glutathione/glutathione disulfide (GSH/GSSG) assay and protein carbonyl formation, respectively. Pro-oxidative or pro-inflammatory factors including advanced glycation end-product (AGE), tissue factor and tumor necrosis factor-alpha (TNF-alpha) were evaluated by immunoblot analysis. Four weeks STZ treatment led to hyperglycemia, enhanced cerebral oxidative stress (reduced GSH/GSSG ratio), elevated TNF-alpha and AGE levels without changes in protein carbonyl or tissue factor. Benfotiamine alleviated diabetes-induced cerebral oxidative stress without affecting levels of AGE, protein carbonyl, tissue factor and TNF-alpha. Collectively, our results indicated benfotiamine may antagonize diabetes-induced cerebral oxidative stress through a mechanism unrelated to AGE, tissue factor and TNF-alpha.

Histone H3 lysine 36 methyltransferase mobilizes NER factors to regulate tolerance against alkylation damage in fission yeast.

Science.gov (United States)

Lim, Kim Kiat; Nguyen, Thi Thuy Trang; Li, Adelicia Yongling; Yeo, Yee Phan; Chen, Ee Sin

2018-04-09

The Set2 methyltransferase and its target, histone H3 lysine 36 (H3K36), affect chromatin architecture during the transcription and repair of DNA double-stranded breaks. Set2 also confers resistance against the alkylating agent, methyl methanesulfonate (MMS), through an unknown mechanism. Here, we show that Schizosaccharomyces pombe (S. pombe) exhibit MMS hypersensitivity when expressing a set2 mutant lacking the catalytic histone methyltransferase domain or a H3K36R mutant (reminiscent of a set2-null mutant). Set2 acts synergistically with base excision repair factors but epistatically with nucleotide excision repair (NER) factors, and determines the timely nuclear accumulation of the NER initiator, Rhp23, in response to MMS. Set2 facilitates Rhp23 recruitment to chromatin at the brc1+ locus, presumably to repair alkylating damage and regulate the expression of brc1+ in response to MMS. Set2 also show epistasis with DNA damage checkpoint proteins; regulates the activation of Chk1, a DNA damage response effector kinase; and acts in a similar functional group as proteins involved in homologous recombination. Consistently, Set2 and H3K36 ensure the dynamicity of Rhp54 in DNA repair foci formation after MMS treatment. Overall, our results indicate a novel role for Set2/H3K36me in coordinating the recruitment of DNA repair machineries to timely manage alkylating damage.

Impact of Age and Insulin-Like Growth Factor-1 on DNA Damage Responses in UV-Irradiated Human Skin.

Science.gov (United States)

Kemp, Michael G; Spandau, Dan F; Travers, Jeffrey B

2017-02-26

The growing incidence of non-melanoma skin cancer (NMSC) necessitates a thorough understanding of its primary risk factors, which include exposure to ultraviolet (UV) wavelengths of sunlight and age. Whereas UV radiation (UVR) has long been known to generate photoproducts in genomic DNA that promote genetic mutations that drive skin carcinogenesis, the mechanism by which age contributes to disease pathogenesis is less understood and has not been sufficiently studied. In this review, we highlight studies that have considered age as a variable in examining DNA damage responses in UV-irradiated skin and then discuss emerging evidence that the reduced production of insulin-like growth factor-1 (IGF-1) by senescent fibroblasts in the dermis of geriatric skin creates an environment that negatively impacts how epidermal keratinocytes respond to UVR-induced DNA damage. In particular, recent data suggest that two principle components of the cellular response to DNA damage, including nucleotide excision repair and DNA damage checkpoint signaling, are both partially defective in keratinocytes with inactive IGF-1 receptors. Overcoming these tumor-promoting conditions in aged skin may therefore provide a way to lower aging-associated skin cancer risk, and thus we will consider how dermal wounding and related clinical interventions may work to rejuvenate the skin, re-activate IGF-1 signaling, and prevent the initiation of NMSC.

Impact of Age and Insulin-Like Growth Factor-1 on DNA Damage Responses in UV-Irradiated Human Skin

Directory of Open Access Journals (Sweden)

Michael G. Kemp

2017-02-01

Full Text Available The growing incidence of non-melanoma skin cancer (NMSC necessitates a thorough understanding of its primary risk factors, which include exposure to ultraviolet (UV wavelengths of sunlight and age. Whereas UV radiation (UVR has long been known to generate photoproducts in genomic DNA that promote genetic mutations that drive skin carcinogenesis, the mechanism by which age contributes to disease pathogenesis is less understood and has not been sufficiently studied. In this review, we highlight studies that have considered age as a variable in examining DNA damage responses in UV-irradiated skin and then discuss emerging evidence that the reduced production of insulin-like growth factor-1 (IGF-1 by senescent fibroblasts in the dermis of geriatric skin creates an environment that negatively impacts how epidermal keratinocytes respond to UVR-induced DNA damage. In particular, recent data suggest that two principle components of the cellular response to DNA damage, including nucleotide excision repair and DNA damage checkpoint signaling, are both partially defective in keratinocytes with inactive IGF-1 receptors. Overcoming these tumor-promoting conditions in aged skin may therefore provide a way to lower aging-associated skin cancer risk, and thus we will consider how dermal wounding and related clinical interventions may work to rejuvenate the skin, re-activate IGF-1 signaling, and prevent the initiation of NMSC.

The impact of earthquakes on the city of Aigio in Greece. Urban planning as a factor in mitigating seismic damage

International Nuclear Information System (INIS)

Athanasopoulou, Evanthia; Despoiniadou, Varvara; Dritsos, Stefanos

2008-01-01

This paper examines the effects of the mortal earthquake on the city of Aigio in Greece in 1995, with particular focus on urbanization and planning policies. It is based on interviews with experts and surveys on damage to buildings following this earthquake. The analysis takes into account several factors, such as exact location, land use, construction period and the height of damaged buildings. Furthermore, the relationship between the seismic damage and the postseismic construction development of Aigio is examined and the conclusion is reached that the Greek urban planning system needs to be better organized to prepare for seismic damage. To this end, the paper recommends a five-point discussion agenda for applying local planning to seismic mitigation

The impact of earthquakes on the city of Aigio in Greece. Urban planning as a factor in mitigating seismic damage.

Science.gov (United States)

Athanasopoulou, Evanthia; Despoiniadou, Varvara; Dritsos, Stefanos

2008-07-01

This paper examines the effects of the mortal earthquake on the city of Aigio in Greece in 1995, with particular focus on urbanization and planning policies. It is based on interviews with experts and surveys on damage to buildings following this earthquake. The analysis takes into account several factors, such as exact location, land use, construction period and the height of damaged buildings. Furthermore, the relationship between the seismic damage and the postseismic construction development of Aigio is examined and the conclusion is reached that the Greek urban planning system needs to be better organized to prepare for seismic damage. To this end, the paper recommends a five-point discussion agenda for applying local planning to seismic mitigation.

Hydrogen damage in stainless steel

International Nuclear Information System (INIS)

Caskey, G.R. Jr.

1981-01-01

Hydrogen damage has been studied in a wide variety of stainless steels. Both internal and external hydrogen damage were evaluated by ductility or J-integral under rising tensile loads and by fractography. Analysis of the data has emphasized the potential effects of strain-induced martensite on hydrogen damage. Strain-induced martensite was neither necessary nor sufficient for hydrogen damage in the alloys studied. Neither ductility loss nor fracture-mode change correlated generally with martensite formation. Alloy composition, particularly nickel and nitrogen contents, was the primary factor in resistance to hydrogen damage. Thermomechanical processing, however, could alter the degree of hydrogen damage in an alloy and was critical for optimizing resistance to hydrogen damage. 10 figures, 10 tables

Both genetic and dietary factors underlie individual differences in DNA damage levels and DNA repair capacity

Czech Academy of Sciences Publication Activity Database

Slyšková, Jana; Lorenzo, Y.; Karlsen, A.; Carlsen, M. H.; Novosadová, Vendula; Blomhoff, R.; Vodička, Pavel; Collins, A. R.

2014-01-01

Roč. 16, APR 2014 (2014), s. 66-73 ISSN 1568-7864 R&D Projects: GA ČR(CZ) GAP304/12/1585 Institutional support: RVO:68378041 ; RVO:86652036 Keywords : DNA damage * DNA repair capacity * diet Subject RIV: EB - Genetics ; Molecular Biology; EI - Biotechnology ; Bionics (BTO-N) Impact factor: 3.111, year: 2014

Evaluate of the Effects of Drilling with Varying Spindle Speed Using Different Thickness of GFRP on the Damage Factor

Directory of Open Access Journals (Sweden)

Keong Woo Tze

2014-07-01

Full Text Available Composite have been widely used in industries which such as aircraft structural components, electric and electronics components, aerospace, and oil and gas fields due to their superior mechanical properties. Among machining process, drilling can be considered as one of the most important process in final machining of composite. In this research, vacuum assisted resin infusion method is use in fabricating the glass fiber reinforcement polymer samples, where different thickness of GFRP were used in the drilling process with different spindle speed. The results show that the temperature influences the damage factor of the drilling. Higher spindle speed will generate higher temperature that softens the matrix thus generating lower damage factor. The suitable drill bit temperature is between 150-200°C

Periodontal tissue damage in smokers

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Hutojo Djajakusuma

2006-09-01

Full Text Available Dental plaque is the primary etiological factor in periodontal diseases. However, there are many factors that can modify how an individual periodontal tissue will respond to the accumulation of dental plaque. Among such risk factors, there is increasing evidence that smoking tobacco products alters the expression and rate of progression of periodontal diseases. The aim of this study was to find out the loss of periodontal tissue adhesion in smokers by measuring pocket depth using probe, and by measuring alveolar bone damage using Bone Loss Score (BLS radiographic methods on teeth 12, 11, 21, 22, 32, 31, 41, 42. Based on T Test statistical analysis, there were significant differences in pocket depth damage of alveolar bone in smokers and non smokers. In conclusion there were increasing pocket depth and alveolar bone damage in smokers.

Accumulated damage evaluation for a piping system by the response factor on non-stationary random process, 2

International Nuclear Information System (INIS)

Shintani, Masanori

1988-01-01

This paper shows that the average and variance of the accumulated damage caused by earthquakes on the piping system attached to a building are related to the seismic response factor λ. The earthquakes refered to in this paper are of a non-stationary random process kind. The average is proportional to λ 2 and the variance to λ 4 . The analytical values of the average and variance for a single-degree-of-freedom system are compared with those obtained from computer simulations. Here the model of the building is a single-degree-of-freedom system. Both average of accumulated damage are approximately equal. The variance obtained from the analysis does not coincide with that from simulations. The reason is considered to be the forced vibraiton by sinusoidal waves, and the sinusoidal waves included random waves. Taking account of amplitude magnification factor, the values of the variance approach those obtained from simulations. (author)

Probabilistic Assessment of Structural Seismic Damage for Buildings in Mid-America

International Nuclear Information System (INIS)

Bai, Jong-Wha; Hueste, Mary Beth D.; Gardoni, Paolo

2008-01-01

This paper provides an approach to conduct a probabilistic assessment of structural damage due to seismic events with an application to typical building structures in Mid-America. The developed methodology includes modified damage state classifications based on the ATC-13 and ATC-38 damage states and the ATC-38 database of building damage. Damage factors are assigned to each damage state to quantify structural damage as a percentage of structural replacement cost. To account for the inherent uncertainties, these factors are expressed as random variables with a Beta distribution. A set of fragility curves, quantifying the structural vulnerability of a building, is mapped onto the developed methodology to determine the expected structural damage. The total structural damage factor for a given seismic intensity is then calculated using a probabilistic approach. Prediction and confidence bands are also constructed to account for the prevailing uncertainties. The expected seismic structural damage is assessed for a typical building structure in the Mid-America region using the developed methodology. The developed methodology provides a transparent procedure, where the structural damage factors can be updated as additional seismic damage data becomes available

Dynamic maps of UV damage formation and repair for the human genome.

Science.gov (United States)

Hu, Jinchuan; Adebali, Ogun; Adar, Sheera; Sancar, Aziz

2017-06-27

Formation and repair of UV-induced DNA damage in human cells are affected by cellular context. To study factors influencing damage formation and repair genome-wide, we developed a highly sensitive single-nucleotide resolution damage mapping method [high-sensitivity damage sequencing (HS-Damage-seq)]. Damage maps of both cyclobutane pyrimidine dimers (CPDs) and pyrimidine-pyrimidone (6-4) photoproducts [(6-4)PPs] from UV-irradiated cellular and naked DNA revealed that the effect of transcription factor binding on bulky adducts formation varies, depending on the specific transcription factor, damage type, and strand. We also generated time-resolved UV damage maps of both CPDs and (6-4)PPs by HS-Damage-seq and compared them to the complementary repair maps of the human genome obtained by excision repair sequencing to gain insight into factors that affect UV-induced DNA damage and repair and ultimately UV carcinogenesis. The combination of the two methods revealed that, whereas UV-induced damage is virtually uniform throughout the genome, repair is affected by chromatin states, transcription, and transcription factor binding, in a manner that depends on the type of DNA damage.

Damage pattern as a function of radiation quality and other factors.

Science.gov (United States)

Burkart, W; Jung, T; Frasch, G

1999-01-01

An understanding of damage pattern in critical cellular structures such as DNA is an important prerequisite for a mechanistic assessment of primary radiation damage, its possible repair, and the propagation of residual changes in somatic and germ cells as potential contributors to disease or ageing. Important quantitative insights have been made recently on the distribution in time and space of critical lesions from direct and indirect action of ionizing radiation on mammalian cells. When compared to damage from chemicals or from spontaneous degradation, e.g. depurination or base deamination in DNA, the potential of even low-LET radiation to create local hot spots of damage from single particle tracks is of utmost importance. This has important repercussions on inferences from critical biological effects at high dose and dose rate exposure situations to health risks at chronic, low-level exposures as experienced in environmental and controlled occupational settings. About 10,000 DNA lesions per human cell nucleus and day from spontaneous degradation and chemical attack cause no apparent effect, but a dose of 4 Gy translating into a similar number of direct and indirect DNA breaks induces acute lethality. Therefore, single lesions cannot explain the high efficiency of ionizing radiation in the induction of mutation, transformation and loss of proliferative capacity. Clustered damage leading to poorly repairable double-strand breaks or even more complex local DNA degradation, correlates better with fixed damage and critical biological endpoints. A comparison with other physical, chemical and biological agents indicates that ionizing radiation is indeed set apart from these by its unique micro- and nano-dosimetric traits. Only a few other agents such as bleomycin have a similar potential to cause complex damage from single events. However, in view of the multi-stage mechanism of carcinogenesis, it is still an open question whether dose-effect linearity for complex

Oxidative damage markers are significantly associated with the carotid artery intima-media thickness after controlling for conventional risk factors of atherosclerosis in men.

Directory of Open Access Journals (Sweden)

Jin-Ha Yoon

Full Text Available This study aimed to assess the association between oxidative damage markers and carotid artery intima-media thickness (CIMT after controlling for conventional risk factors of atherosclerosis in multiple logistic regression models.Fifty-one case male participants (CIMT ≥ 0.9 mm were enrolled during their visits to Korean Genomic Rural Cohort Study of Wonju centers between May 1 and August 31, 2011, along with 51 control participants (CIMT < 0.9 mm selected using frequency matching by age group. The levels of oxidative damage markers, 8-hydroxy-2'-deoxyquuanosine (8-OHdG, malondialdehyde (MDA, and 8-iso-prostaglandin F2α (Isoprostane, were measured. Conditional logistic regression models were used to evaluate relative relationships between the oxidative damage markers and the risk of high CIMT.The markers of oxidative lipid (Isoprostane and MDA and DNA (8-OHdG damage were associated with CIMT after controlling for the conventional risk factors, including age, low density lipoprotein, body mass index, smoking history, alcohol consumption, and metabolic syndrome (ORs [95% CI] for Isoprostane: 3rd tertile, 8.47 [2.59-27.67]; for MDA: 3rd tertile, 8.47 [2.59-27.67]; for 8-OHdG: 3rd tertile, 5.58 [1.79-17.33]. When all the oxidative damage markers were incorporated in the same logistic regression model, only Isoprostane was significantly related to CIMT (OR [95% CI]: 4.22 [1.31-13.53] in 2nd tertile and 14.21 [3.34-60.56] in 3rd tertile.In this nested case-control study, the oxidative damage markers of lipid and DNA were associated with CIMT even after controlling for the conventional risk factors of cardiovascular diseases.

Oxidative stress damage as a detrimental factor in preterm birth pathology.

Science.gov (United States)

Menon, Ramkumar

2014-01-01

Normal term and spontaneous preterm births (PTB) are documented to be associated with oxidative stress (OS), and imbalances in the redox system (balance between pro- and antioxidant) have been reported in the maternal-fetal intrauterine compartments. The exact mechanism of labor initiation either at term or preterm by OS is still unclear, and this lack of understanding can partially be blamed for failure of antioxidant supplementation trials in PTB prevention. Based on recent findings from our laboratory, we postulate heterogeneity in host OS response. The physiologic (at term) and pathophysiologic (preterm) pathways of labor are not mediated by OS alone but by OS-induced damage to intrauterine tissues, especially fetal membranes of the placenta. OS damage affects all major cellular elements in the fetal cells, and this damage promotes fetal cell senescence (aging). The aging of the fetal cells is predominated by p38 mitogen activated kinase (p38MAPK) pathways. Senescing cells generate biomolecular signals that are uterotonic, triggering labor process. The aging of fetal cells is normal at term. However, aging is premature in PTB, especially in those PTBs complicated by preterm premature rupture of the membranes, where elements of redox imbalances and OS damage are more dominant. We postulate that fetal cell senescence signals generated by OS damage are likely triggers for labor. This review highlights the mechanisms involved in senescence development at term and preterm by OS damage and provides insight into novel fetal signals of labor initiation pathways.

Oxidative stress damage as a detrimental factor in preterm birth pathology

Directory of Open Access Journals (Sweden)

Ramkumar eMenon

2014-11-01

Full Text Available Normal term and spontaneous preterm births (PTB are documented to be associated with oxidative stress (OS, and imbalances in the redox system (balance between pro- and antioxidant have been reported in the maternal-fetal intrauterine compartments. The exact mechanism of labor initiation either at term or preterm by OS is still unclear, and this lack of understanding can partially be blamed for failure of antioxidant supplementation trials in PTB prevention. Based on recent findings from our laboratory, we postulate heterogeneity in host OS response. The physiologic (at term and pathophysiologic (preterm pathways of labor are not mediated by OS alone but by OS-induced damage to intrauterine tissues, especially fetal membranes of the placenta. OS damage affects all major cellular elements in the fetal cells, and this damage promotes fetal cell senescence (aging. The aging of the fetal cells are predominated by p38 mitogen activated kinase (p38MAPK pathways. Senescing cells generate biomolecular signals that are uterotonic, triggering labor process. The aging of fetal cells is normal at term. However, aging is premature in PTB, especially in those PTBs complicated by preterm premature rupture of the membranes (pPROM, where elements of redox imbalances and OS damage are more dominant. We postulate that fetal cell senescence signals generated by OS damage are likely triggers for labor. This review highlights the mechanisms involved in senescence development at term and preterm by OS damage and provides insight into novel fetal signals of labor initiation pathways.

Residential damage in an area of underground coal mining

International Nuclear Information System (INIS)

Padgett, M.F.

1988-01-01

In order to estimate the potential for future subsidence-related residential damage, a statistical analysis of past residential damage in the Boulder-Weld, Colorado, coal field was performed. The objectives of this study were to assess the difference in damage severity and frequency between undermined and non-undermined areas, and to determine, where applicable, which mining factors significantly influence the severity and frequency of residential damage. The results of this study suggest that undermined homes have almost three times the risk of having some type of structural damage than do non-undermined homes. The study also indicated that both geologic factors, such as the ratio of sandstone/claystone in the overburden, and mining factors, such as the mining feature (room, pillar, entry, etc.), can significantly affect the severity of overlying residential damage. However, the results of this study are dependent on local conditions and should not be applied elsewhere unless the geologic, mining, and residential conditions are similar

Independent association of glucocorticoids with damage accrual in SLE.

Science.gov (United States)

Apostolopoulos, Diane; Kandane-Rathnayake, Rangi; Raghunath, Sudha; Hoi, Alberta; Nikpour, Mandana; Morand, Eric F

2016-01-01

To determine factors associated with damage accrual in a prospective cohort of patients with SLE. Patients with SLE who attended the Lupus Clinic at Monash Health, Australia, between 2007 and 2013 were studied. Clinical variables included disease activity (Systemic Lupus Erythematosus Disease Activity Index-2K, SLEDAI-2K), time-adjusted mean SLEDAI, cumulative glucocorticoid dose and organ damage (Systemic Lupus International Collaborating Clinics Damage Index (SDI)). Multivariate logistic regression analyses were performed to identify factors associated with damage accrual. A total of 162 patients were observed over a median (IQR) 3.6 (2.0-4.7) years. Seventy-five per cent (n=121) of patients received glucocorticoids. Damage accrual was significantly more frequent in glucocorticoid-exposed patients (42% vs 15%, p<0.01). Higher glucocorticoid exposure was independently associated with overall damage accrual after controlling for factors including ethnicity and disease activity and was significant at time-adjusted mean doses above 4.42 mg prednisolone/day; the OR of damage accrual in patients in the highest quartile of cumulative glucocorticoid exposure was over 10. Glucocorticoid exposure was independently associated with damage accrual in glucocorticoid-related and non-glucocorticoid related domains of the SDI. Glucocorticoid use is independently associated with the accrual of damage in SLE, including in non-glucocorticoid related domains.

Continuum damage mechanics analysis of crack tip zone

International Nuclear Information System (INIS)

Yinchu, L.; Jianping, Z.

1989-01-01

The crack tip field and its intensity factor play an important role in fracture mechanics. Generally, the damage such as microcracks, microvoids etc. will initiate and grow in materials as the cracked body is subjected to external loadings, especially in the crack tip zone. The damage evolution will load to the crack tip damage field and the change of the stress, strain and displacement fields of cracks tip zone. In this paper, on the basis of continuum damage mechanics, the authors have derived the equations which the crack tip field and its intensity factor must satisfy in a loading process, calculated the angle distribution curves of stress, strain and displacement fields in a crack tip zone and have compared them with the corresponding curves of HRR field and linear elastic field in undamaged materials. The equations of crack tip field intensity factors have been solved and its solutions give the variation of the field intensity factors with the loading parameter

The nucleosome: orchestrating DNA damage signaling and repair within chromatin.

Science.gov (United States)

Agarwal, Poonam; Miller, Kyle M

2016-10-01

DNA damage occurs within the chromatin environment, which ultimately participates in regulating DNA damage response (DDR) pathways and repair of the lesion. DNA damage activates a cascade of signaling events that extensively modulates chromatin structure and organization to coordinate DDR factor recruitment to the break and repair, whilst also promoting the maintenance of normal chromatin functions within the damaged region. For example, DDR pathways must avoid conflicts between other DNA-based processes that function within the context of chromatin, including transcription and replication. The molecular mechanisms governing the recognition, target specificity, and recruitment of DDR factors and enzymes to the fundamental repeating unit of chromatin, i.e., the nucleosome, are poorly understood. Here we present our current view of how chromatin recognition by DDR factors is achieved at the level of the nucleosome. Emerging evidence suggests that the nucleosome surface, including the nucleosome acidic patch, promotes the binding and activity of several DNA damage factors on chromatin. Thus, in addition to interactions with damaged DNA and histone modifications, nucleosome recognition by DDR factors plays a key role in orchestrating the requisite chromatin response to maintain both genome and epigenome integrity.

Analysis of factors influencing fire damage to concrete using nonlinear resonance vibration method

Energy Technology Data Exchange (ETDEWEB)

Park, Gang Kyu; Park, Sun Jong; Kwak, Hyo Gyoung [Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, KAIST, Daejeon (Korea, Republic of); Yim, Hong Jae [Dept. of Construction and Disaster Prevention Engineering, Kyungpook National University, Sangju (Korea, Republic of)

2015-04-15

In this study, the effects of different mix proportions and fire scenarios (exposure temperatures and post-fire-curing periods) on fire-damaged concrete were analyzed using a nonlinear resonance vibration method based on nonlinear acoustics. The hysteretic nonlinearity parameter was obtained, which can sensitively reflect the damage level of fire-damaged concrete. In addition, a splitting tensile strength test was performed on each fire-damaged specimen to evaluate the residual property. Using the results, a prediction model for estimating the residual strength of fire-damaged concrete was proposed on the basis of the correlation between the hysteretic nonlinearity parameter and the ratio of splitting tensile strength.

[Prevalence of target organ damage and factors associated with cardiovascular events in subjects with refractory hypertension].

Science.gov (United States)

Armario, Pedro; Oliveras, Anna; Hernández Del Rey, Raquel; Poch, Esteban; Larrouse, María; Roca-Cusachs, Alex; de la Sierra, Alejandro

2009-06-27

To asses the prevalence of target organ damage (TOD) and factors associated with cardiovascular events in subjects with refractory hypertension. Cross-sectional study of 146 patients with clinical diagnosis of refractory hypertension. TOD was defined as the presence of microalbuminuria (MA), renal failure (RF), left ventricular hypertrophy (LVH) or left atrial enlargement (LAE). Cardiovascular events were defined as the antecedent of stroke, coronary heart disease, heart failure or peripheral arterial disease. 24-h ambulatory blood pressure monitoring was (ABPM) performed with a validated Spacelabs 90207. The prevalence of LVH was 62.3%, and LAE was observed in 27.7% of the subjects. The prevalence of RF was 28.1% and MA was found in 41,4%. An association between MA and LVH was observed. After adjusting by age, the urinary albumin excretion (UAE) correlated with clinical blood pressure (BP) and BP during 24-h ABPM, whereas LVMI correlated with ambulatory BP but not with clinical BP. The prevalence of previous cardiovascular events was 22% and in the multivariate regression analysis, UAE was the only independent factor associated with the antecedent of cardiovascular events. In subjects with refractory hypertension, the prevalence of TOD was high, and an association between heart and renal organ damage was observed. UAE was independently associated with the antecedent of cardiovascular disease.

Deficiency in the nuclear factor E2-related factor 2 renders pancreatic β-cells vulnerable to arsenic-induced cell damage

International Nuclear Information System (INIS)

Yang, Bei; Fu, Jingqi; Zheng, Hongzhi; Xue, Peng; Yarborough, Kathy; Woods, Courtney G.; Hou, Yongyong; Zhang, Qiang; Andersen, Melvin E.; Pi, Jingbo

2012-01-01

Chronic human exposure to inorganic arsenic (iAs), a potent environmental oxidative stressor, is associated with increased prevalence of type 2 diabetes, where impairment of pancreatic β-cell function is a key pathogenic factor. Nuclear factor E2-related factor 2 (Nrf2) is a central transcription factor regulating cellular adaptive response to oxidative stress. However, persistent activation of Nrf2 in response to chronic oxidative stress, including inorganic arsenite (iAs 3+ ) exposure, blunts glucose-triggered reactive oxygen species (ROS) signaling and impairs glucose-stimulated insulin secretion (GSIS). In the current study, we found that MIN6 pancreatic β-cells with stable knockdown of Nrf2 (Nrf2-KD) by lentiviral shRNA and pancreatic islets isolated from Nrf2-knockout (Nrf2−/−) mice exhibited reduced expression of several antioxidant and detoxification enzymes in response to acute iAs 3+ exposure. As a result, Nrf2-KD MIN6 cells and Nrf2−/− islets were more susceptible to iAs 3+ and monomethylarsonous acid (MMA 3+ )-induced cell damage, as measured by decreased cell viability, augmented apoptosis and morphological change. Pretreatment of MIN6 cells with Nrf2 activator tert-butylhydroquinone protected the cells from iAs 3+ -induced cell damage in an Nrf2-dependent fashion. In contrast, antioxidant N‐acetyl cysteine protected Nrf2-KD MIN6 cells against acute cytotoxicity of iAs 3+ . The present study demonstrates that Nrf2-mediated antioxidant response is critical in the pancreatic β-cell defense mechanism against acute cytotoxicity by arsenic. The findings here, combined with our previous results on the inhibitory effect of antioxidants on ROS signaling and GSIS, suggest that Nrf2 plays paradoxical roles in pancreatic β-cell dysfunction induced by environmental arsenic exposure. -- Highlights: ► Lack of Nrf2 reduced expression of antioxidant genes induced by iAs 3+ in β-cells. ► Deficiency of Nrf2 in β-cells sensitized to iAs 3+ and MMA 3

Deficiency in the nuclear factor E2-related factor 2 renders pancreatic β-cells vulnerable to arsenic-induced cell damage

Energy Technology Data Exchange (ETDEWEB)

Yang, Bei [Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709 (United States); Department of Histology and Embryology, College of Basic Medical Sciences, China Medical University, Shenyang 110001 (China); Fu, Jingqi; Zheng, Hongzhi; Xue, Peng; Yarborough, Kathy; Woods, Courtney G.; Hou, Yongyong; Zhang, Qiang; Andersen, Melvin E. [Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709 (United States); Pi, Jingbo, E-mail: jpi@thehamner.org [Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709 (United States)

2012-11-01

Chronic human exposure to inorganic arsenic (iAs), a potent environmental oxidative stressor, is associated with increased prevalence of type 2 diabetes, where impairment of pancreatic β-cell function is a key pathogenic factor. Nuclear factor E2-related factor 2 (Nrf2) is a central transcription factor regulating cellular adaptive response to oxidative stress. However, persistent activation of Nrf2 in response to chronic oxidative stress, including inorganic arsenite (iAs{sup 3+}) exposure, blunts glucose-triggered reactive oxygen species (ROS) signaling and impairs glucose-stimulated insulin secretion (GSIS). In the current study, we found that MIN6 pancreatic β-cells with stable knockdown of Nrf2 (Nrf2-KD) by lentiviral shRNA and pancreatic islets isolated from Nrf2-knockout (Nrf2−/−) mice exhibited reduced expression of several antioxidant and detoxification enzymes in response to acute iAs{sup 3+} exposure. As a result, Nrf2-KD MIN6 cells and Nrf2−/− islets were more susceptible to iAs{sup 3+} and monomethylarsonous acid (MMA{sup 3+})-induced cell damage, as measured by decreased cell viability, augmented apoptosis and morphological change. Pretreatment of MIN6 cells with Nrf2 activator tert-butylhydroquinone protected the cells from iAs{sup 3+}-induced cell damage in an Nrf2-dependent fashion. In contrast, antioxidant N‐acetyl cysteine protected Nrf2-KD MIN6 cells against acute cytotoxicity of iAs{sup 3+}. The present study demonstrates that Nrf2-mediated antioxidant response is critical in the pancreatic β-cell defense mechanism against acute cytotoxicity by arsenic. The findings here, combined with our previous results on the inhibitory effect of antioxidants on ROS signaling and GSIS, suggest that Nrf2 plays paradoxical roles in pancreatic β-cell dysfunction induced by environmental arsenic exposure. -- Highlights: ► Lack of Nrf2 reduced expression of antioxidant genes induced by iAs{sup 3+} in β-cells. ► Deficiency of Nrf2 in �

Ion-induced damage and amorphization in Si

International Nuclear Information System (INIS)

Holland, O.W.; White, C.W.

1990-01-01

Ion-induced damage growth in high-energy, self-ion irradiated Si was studied using electron microscopy and Rutherford backscattering spectroscopy. The results show that there is a marked variation in the rate of damage growth, as well as the damage morphology, along the path of the ion. Near the ion end-of-range (eor), damage increases monotonically with ion fluence until a buried amorphous layer is formed, while damage growth saturates at a low level in the region ahead. The morphology of the damage in the saturated region is shown to consist predominantly of simple defect clusters such as the divacancy. Damage growth remains saturated ahead of the eor until expansion of the buried amorphous layer encroaches into the region. A homogeneous growth model is presented which accounts for damage saturation, and accurately predicts the dose-rate dependence of the saturation level. Modifications of the model are discussed which are needed to account for the rapid growth in the eor region and near the interface of the buried amorphous layer. Two important factors contributing to rapid damage growth are identified. Spatial separation of the Frenkel defect pairs (i.e. interstitials and vacancies) due to the momentum of the interstitials is shown to greatly impact damage growth near the eor, while uniaxial strain in the interfacial region of the amorphous layer is identified as an important factor contributing to growth at that location. 20 refs., 10 figs

The role of platelet factor 4 in local and remote tissue damage in a mouse model of mesenteric ischemia/reperfusion injury.

Directory of Open Access Journals (Sweden)

Peter H Lapchak

Full Text Available The robust inflammatory response that occurs during ischemia reperfusion (IR injury recruits factors from both the innate and adaptive immune systems. However the contribution of platelets and their products such as Platelet Factor 4 (PF4; CXCL4, during the pathogenesis of IR injury has not been thoroughly investigated. We show that a deficiency in PF4 protects mice from local and remote tissue damage after 30 minutes of mesenteric ischemia and 3 hours of reperfusion in PF4-/- mice compared to control B6 mice. This protection was independent from Ig or complement deposition in the tissues. However, neutrophil and monocyte infiltration were decreased in the lungs of PF4-/- mice compared with B6 control mice. Platelet-depleted B6 mice transfused with platelets from PF4-/- mice displayed reduced tissue damage compared with controls. In contrast, transfusion of B6 platelets into platelet depleted PF4-/- mice reconstituted damage in both intestine and lung tissues. We also show that PF4 may modulate the release of IgA. Interestingly, we show that PF4 expression on intestinal epithelial cells is increased after IR at both the mRNA and protein levels. In conclusion, these findings demonstrate that may PF4 represent an important mediator of local and remote tissue damage.

Fungi in Ontario maple syrup & some factors that determine the presence of mold damage.

Science.gov (United States)

Frasz, Samantha L; Miller, J David

2015-08-17

Maple syrup is a high value artisanal product produced mainly in Canada and a number of States primarily in the northeast USA. Mold growth (Wallemia sebi) on commercial product was first reported in syrup in 1908. Since then, few data have been published. We conducted a systematic examination for fungi in maple syrup from 68 producers from all of the syrup-producing areas of Ontario, Canada. The mean pH of the samples was pH 6.82, sugar content averaged 68.0±0.89 °Brix and aw averaged 0.841±0.011. Some 23 species of fungi were isolated based on morphology and molecular techniques. The most common fungus in the maple syrup samples was Eurotium herbariorum, followed by Penicillium chrysogenum, Aspergillus penicillioides, Aspergillus restrictus, Aspergillus versicolor and two species of Wallemia. Cladosporium cladosporioides was also common but only recovered when fungi known from high sugar substrates were also present in the mold damaged sample. The rarely reported yeast Citeromyces matrinsis was found in samples from three producers. There appear to be three potential causes for mold damage observed. High aw was associated with about one third of the mold damage. Independently, cold packing (bottling at ~25 °C) was a risk factor. However, syrup of good quality and quite low aw values was contaminated. We hypothesize that sanitation in the bottling line and other aspects of the bottling process may be partial explanations. Clarifying this requires further study. Copyright © 2015 Elsevier B.V. All rights reserved.

IMA status seminar 'biotic damaging factors/epidemiology'. Summaries. IMA-Statusseminar 'Biotische Schadfaktoren/Epidemiologie'. Kurzberichte

Energy Technology Data Exchange (ETDEWEB)

Stuettgen, E. (ed.)

1986-07-01

This workshop is concerned primarily with the effects of biotic factors on forest decline. The possible involvement of viruses, mycoplasma-like organisms (MLO), rickettsia-like bacteria (RLB), fungi, insects and nematodes in diseases and pests of forest trees has to be investigated. Beside abiotic factors these agents are the cause of different die-back symptoms and damage of trees, but it is not yet known to what extent they contribute to the symptoms man associate with the forest decline ''Waldsterben''.

Subclinical organ damage and cardiovascular risk prediction

DEFF Research Database (Denmark)

Sehestedt, Thomas; Olsen, Michael H

2010-01-01

Traditional cardiovascular risk factors have poor prognostic value for individuals and screening for subclinical organ damage has been recommended in hypertension in recent guidelines. The aim of this review was to investigate the clinical impact of the additive prognostic information provided...... by measuring subclinical organ damage. We have (i) reviewed recent studies linking markers of subclinical organ damage in the heart, blood vessels and kidney to cardiovascular risk; (ii) discussed the evidence for improvement in cardiovascular risk prediction using markers of subclinical organ damage; (iii...

Systems Biology Model of Interactions Between Tissue Growth Factors and DNA Damage Pathways: Low Dose Response and Cross-Talk in TGFbeta and ATM Signaling

Energy Technology Data Exchange (ETDEWEB)

O' Neill, Peter [University of Oxford; Anderson, Jennifer [University of Oxford

2014-10-02

The etiology of radiation carcinogenesis has been described in terms of aberrant changes that span several levels of biological organization. Growth factors regulate many important cellular and tissue functions including apoptosis, differentiation and proliferation. A variety of genetic and epigenetic changes of growth factors have been shown to contribute to cancer initiation and progression. It is known that cellular and tissue damage to ionizing radiation is in part initiated by the production of reactive oxygen species, which can activate cytokine signaling, and the DNA damage response pathways, most notably the ATM signaling pathway. Recently the transforming growth factor β (TGFβ) pathway has been shown to regulate or directly interact with the ATM pathway in the response to radiation. The relevance of this interaction with the ATM pathway is not known although p53 becomes phosphorylated and DNA damage responses are involved. However, growth factor interactions with DNA damage responses have not been elucidated particularly at low doses and further characterization of their relationship to cancer processes is warranted. Our goal will be to use a systems biology approach to mathematically and experimentally describe the low dose responses and cross-talk between the ATM and TGFβ pathways initiated by low and high LET radiation. We will characterize ATM and TGFβ signaling in epithelial and fibroblast cells using 2D models and ultimately extending to 3D organotypic cell culture models to begin to elucidate possible differences that may occur for different cell types and/or inter-cellular communication. We will investigate the roles of the Smad and Activating transcription factor 2 (ATF2) proteins as the potential major contributors to cross- talk between the TGFβ and ATM pathways, and links to cell cycle control and/or the DNA damage response, and potential differences in their responses at low and high doses. We have developed various experimental

Systems Biology Model of Interactions between Tissue Growth Factors and DNA Damage Pathways: Low Dose Response and Cross-Talk in TGFβ and ATM Signaling

International Nuclear Information System (INIS)

Cucinotta, Francis A

2016-01-01

The etiology of radiation carcinogenesis has been described in terms of aberrant changes that span several levels of biological organization. Growth factors regulate many important cellular and tissue functions including apoptosis, differentiation and proliferation. A variety of genetic and epigenetic changes of growth factors have been shown to contribute to cancer initiation and progression. It is known that cellular and tissue damage to ionizing radiation is in part initiated by the production of reactive oxygen species, which can activate cytokine signaling, and the DNA damage response pathways, most notably the ATM signaling pathway. Recently, the transforming growth factor β (TGFβ) pathway has been shown to regulate or directly interact with the ATM pathway in the response to radiation. The relevance of this interaction with the ATM pathway is not known although p53 becomes phosphorylated and DNA damage responses are involved. However, growth factor interactions with DNA damage responses have not been elucidated particularly at low doses, and further characterization of their relationship to cancer processes is warranted. Our goal will be to use a systems biology approach to mathematically and experimentally describe the low-dose responses and cross-talk between the ATM and TGFβ pathways initiated by low- and high-LET radiation. We will characterize ATM and TGFβ signaling in epithelial and fibroblast cells using 2D models and ultimately extending to 3D organotypic cell culture models to begin to elucidate possible differences that may occur for different cell types and/or inter-cellular communication. We will investigate the roles of the Smad and Activating transcription factor 2 (ATF2) proteins as the potential major contributors to crosstalk between the TGFβ and ATM pathways, and links to cell cycle control and/or the DNA damage response, and potential differences in their responses at low and high doses. We have developed various experimental

Systems Biology Model of Interactions between Tissue Growth Factors and DNA Damage Pathways: Low Dose Response and Cross-Talk in TGFβ and ATM Signaling

Energy Technology Data Exchange (ETDEWEB)

Cucinotta, Francis A [Univ. of Nevada, Las Vegas, NV (United States)

2016-09-01

The etiology of radiation carcinogenesis has been described in terms of aberrant changes that span several levels of biological organization. Growth factors regulate many important cellular and tissue functions including apoptosis, differentiation and proliferation. A variety of genetic and epigenetic changes of growth factors have been shown to contribute to cancer initiation and progression. It is known that cellular and tissue damage to ionizing radiation is in part initiated by the production of reactive oxygen species, which can activate cytokine signaling, and the DNA damage response pathways, most notably the ATM signaling pathway. Recently, the transforming growth factor β (TGFβ) pathway has been shown to regulate or directly interact with the ATM pathway in the response to radiation. The relevance of this interaction with the ATM pathway is not known although p53 becomes phosphorylated and DNA damage responses are involved. However, growth factor interactions with DNA damage responses have not been elucidated particularly at low doses, and further characterization of their relationship to cancer processes is warranted. Our goal will be to use a systems biology approach to mathematically and experimentally describe the low-dose responses and cross-talk between the ATM and TGFβ pathways initiated by low- and high-LET radiation. We will characterize ATM and TGFβ signaling in epithelial and fibroblast cells using 2D models and ultimately extending to 3D organotypic cell culture models to begin to elucidate possible differences that may occur for different cell types and/or inter-cellular communication. We will investigate the roles of the Smad and Activating transcription factor 2 (ATF2) proteins as the potential major contributors to crosstalk between the TGFβ and ATM pathways, and links to cell cycle control and/or the DNA damage response, and potential differences in their responses at low and high doses. We have developed various experimental

Experimental Damage Identification of a Model Reticulated Shell

Directory of Open Access Journals (Sweden)

Jing Xu

2017-04-01

Full Text Available The damage identification of a reticulated shell is a challenging task, facing various difficulties, such as the large number of degrees of freedom (DOFs, the phenomenon of modal localization and transition, and low modeling accuracy. Based on structural vibration responses, the damage identification of a reticulated shell was studied. At first, the auto-regressive (AR time series model was established based on the acceleration responses of the reticulated shell. According to the changes in the coefficients of the AR model between the damaged conditions and the undamaged condition, the damage of the reticulated shell can be detected. In addition, the damage sensitive factors were determined based on the coefficients of the AR model. With the damage sensitive factors as the inputs and the damage positions as the outputs, back-propagation neural networks (BPNNs were then established and were trained using the Levenberg–Marquardt algorithm (L–M algorithm. The locations of the damages can be predicted by the back-propagation neural networks. At last, according to the experimental scheme of single-point excitation and multi-point responses, the impact experiments on a K6 shell model with a scale of 1/10 were conducted. The experimental results verified the efficiency of the proposed damage identification method based on the AR time series model and back-propagation neural networks. The proposed damage identification method can ensure the safety of the practical engineering to some extent.

A measure of vulnerability and damage tolerance

International Nuclear Information System (INIS)

Lind, Niels C.

1995-01-01

The purpose of the paper is to present probabilistic definitions of 'vulnerability' and 'damage tolerance'. A new measure of damage is also proposed. Disastrous failures, such as of the Titanic or the Chernobyl reactor, have revealed that some systems can be highly vulnerable. A seemingly insignificant damage can reduce such a system's resistance severely. Attempts to write design code requirements for damage tolerance or structural integrity have not been successful so far. One reason is that these ideas have not been defined with the necessary precision. The suggested definitions aim to be general, applicable to all engineered systems, and readily specializable to particular system types. Vulnerability is defined as the ratio of the failure probability of the damaged system to the failure probability of the undamaged system. It is argued that 'vulnerability' and 'damage tolerance' are complementary concepts. Damage tolerance is defined as the reciprocal of vulnerability. Vulnerability and damage tolerance both concern hypothetical future damage. A damage factor, applicable for the analysis of an existing structure in an assessed state of damage, is defined analogous to vulnerability. Application is illustrated by examples

Study on creep damage behaviors of Ni-based alloy C276

International Nuclear Information System (INIS)

Mao Xueping; Guo Qi; Zhang Shengyuan; Hu Suyang; Lu Daogang; Xu Hong

2013-01-01

High temperature creep tests were carried out for Ni-based alloy C276 at 650℃, 700℃ and 750℃, which is one of the candidate materials for the fuel cladding of the supercritical water reactor. Methods of damage mechanics were adopted to calculate and analyze these data. Damage factors calculated by Kachanov formula and Norton formula based on θ projection method were compared. The results show that the damage factors about the material are similar at the three temperatures according to Kachanov formula. The predicted creep curves calculated by θ projection method have a close agreement with the experimental data. The damages calculated by Norton formula start at about 0.3 - 0.4 lifetime, and the damage factors calculated by Kachanov formula are relatively conservative. (authors)

Meta-analysis of attitudes toward damage-causing mammalian wildlife.

Science.gov (United States)

Kansky, Ruth; Kidd, Martin; Knight, Andrew T

2014-08-01

Many populations of threatened mammals persist outside formally protected areas, and their survival depends on the willingness of communities to coexist with them. An understanding of the attitudes, and specifically the tolerance, of individuals and communities and the factors that determine these is therefore fundamental to designing strategies to alleviate human-wildlife conflict. We conducted a meta-analysis to identify factors that affected attitudes toward 4 groups of terrestrial mammals. Elephants (65%) elicited the most positive attitudes, followed by primates (55%), ungulates (53%), and carnivores (44%). Urban residents presented the most positive attitudes (80%), followed by commercial farmers (51%) and communal farmers (26%). A tolerance to damage index showed that human tolerance of ungulates and primates was proportional to the probability of experiencing damage while elephants elicited tolerance levels higher than anticipated and carnivores elicited tolerance levels lower than anticipated. Contrary to conventional wisdom, experiencing damage was not always the dominant factor determining attitudes. Communal farmers had a lower probability of being positive toward carnivores irrespective of probability of experiencing damage, while commercial farmers and urban residents were more likely to be positive toward carnivores irrespective of damage. Urban residents were more likely to be positive toward ungulates, elephants, and primates when probability of damage was low, but not when it was high. Commercial and communal farmers had a higher probability of being positive toward ungulates, primates, and elephants irrespective of probability of experiencing damage. Taxonomic bias may therefore be important. Identifying the distinct factors explaining these attitudes and the specific contexts in which they operate, inclusive of the species causing damage, will be essential for prioritizing conservation investments. © 2014 The Authors. Conservation Biology

Polyphosphate is a key factor for cell survival after DNA damage in eukaryotic cells.

Science.gov (United States)

Bru, Samuel; Samper-Martín, Bàrbara; Quandt, Eva; Hernández-Ortega, Sara; Martínez-Laínez, Joan M; Garí, Eloi; Rafel, Marta; Torres-Torronteras, Javier; Martí, Ramón; Ribeiro, Mariana P C; Jiménez, Javier; Clotet, Josep

2017-09-01

Cells require extra amounts of dNTPs to repair DNA after damage. Polyphosphate (polyP) is an evolutionary conserved linear polymer of up to several hundred inorganic phosphate (Pi) residues that is involved in many functions, including Pi storage. In the present article, we report on findings demonstrating that polyP functions as a source of Pi when required to sustain the dNTP increment essential for DNA repair after damage. We show that mutant yeast cells without polyP produce less dNTPs upon DNA damage and that their survival is compromised. In contrast, when polyP levels are ectopically increased, yeast cells become more resistant to DNA damage. More importantly, we show that when polyP is reduced in HEK293 mammalian cell line cells and in human dermal primary fibroblasts (HDFa), these cells become more sensitive to DNA damage, suggesting that the protective role of polyP against DNA damage is evolutionary conserved. In conclusion, we present polyP as a molecule involved in resistance to DNA damage and suggest that polyP may be a putative target for new approaches in cancer treatment or prevention. Copyright © 2017 Elsevier B.V. All rights reserved.

Wiring Damage Analyses for STS OV-103

Science.gov (United States)

Thomas, Walter, III

2006-01-01

This study investigated the Shuttle Program s belief that Space Transportation System (STS) wiring damage occurrences are random, that is, a constant occurrence rate. Using Problem Reporting and Corrective Action (PRACA)-derived data for STS Space Shuttle OV-103, wiring damage was observed to increase over the vehicle s life. Causal factors could include wiring physical deterioration, maintenance and inspection induced damage, and inspection process changes resulting in more damage events being reported. Induced damage effects cannot be resolved with existent data. Growth analysis (using Crow-AMSAA, or CA) resolved maintenance/inspection effects (e.g., heightened awareness) on all wire damages and indicated an overall increase since Challenger Return-to-Flight (RTF). An increasing failure or occurrence rate per flight cycle was seen for each wire damage mode; these (individual) rates were not affected by inspection process effects, within statistical error.

Heat shock factor-1 modulates p53 activity in the transcriptional response to DNA damage

Science.gov (United States)

Logan, Ian R.; McNeill, Hesta V.; Cook, Susan; Lu, Xiaohong; Meek, David W.; Fuller-Pace, Frances V.; Lunec, John; Robson, Craig N.

2009-01-01

Here we define an important role for heat shock factor 1 (HSF1) in the cellular response to genotoxic agents. We demonstrate for the first time that HSF1 can complex with nuclear p53 and that both proteins are co-operatively recruited to p53-responsive genes such as p21. Analysis of natural and synthetic cis elements demonstrates that HSF1 can enhance p53-mediated transcription, whilst depletion of HSF1 reduces the expression of p53-responsive transcripts. We find that HSF1 is required for optimal p21 expression and p53-mediated cell-cycle arrest in response to genotoxins while loss of HSF1 attenuates apoptosis in response to these agents. To explain these novel properties of HSF1 we show that HSF1 can complex with DNA damage kinases ATR and Chk1 to effect p53 phosphorylation in response to DNA damage. Our data reveal HSF1 as a key transcriptional regulator in response to genotoxic compounds widely used in the clinical setting, and suggest that HSF1 will contribute to the efficacy of these agents. PMID:19295133

Early models of DNA damage formation

International Nuclear Information System (INIS)

Śmiałek, Małgorzata A

2012-01-01

Quantification of DNA damage, induced by various types of incident radiation as well as chemical agents, has been the subject of many theoretical and experimental studies, supporting the development of modern cancer therapy. The primary observations showed that many factors can lead to damage of DNA molecules. It became clear that the development of experimental techniques for exploring this phenomenon is required. Another problem was simultaneously dealt with, anticipating on how the damage is distributed within the double helix of the DNA molecule and how the single strand break formation and accumulation can influence the lethal double strand break formation. In this work the most important probabilistic models for DNA strand breakage and damage propagation are summarized and compared.

Damage accumulation in ceramics during ion implantation

International Nuclear Information System (INIS)

McHargue, C.J.; Farlow, G.C.; Begun, G.M.; Williams, J.M.; White, C.W.; Appleton, B.R.; Sklad, P.S.; Angelini, P.

1985-01-01

The damage structures of α-Al 2 O 3 and α-SiC were examined as functions of ion implantation parameters using Rutherford backscattering-channeling, analytical electron microscopy, and Raman spectroscopy. Low temperatures or high fluences of cations favor formation of the amorphous state. At 300 0 K, mass of the bombarding species has only a small effect on residual damage, but certain ion species appear to stabilize the damage microstructure and increase the rate of approach to the amorphous state. The type of chemical bonding present in the host lattice is an important factor in determining the residual damage state

Radiation damage prediction system using damage function

International Nuclear Information System (INIS)

Tanaka, Yoshihisa; Mori, Seiji

1979-01-01

The irradiation damage analysis system using a damage function was investigated. This irradiation damage analysis system consists of the following three processes, the unfolding of a damage function, the calculation of the neutron flux spectrum of the object of damage analysis and the estimation of irradiation effect of the object of damage analysis. The damage function is calculated by applying the SAND-2 code. The ANISN and DOT3, 5 codes are used to calculate neutron flux. The neutron radiation and the allowable time of reactor operation can be estimated based on these calculations of the damage function and neutron flux. The flow diagram of the process of analyzing irradiation damage by a damage function and the flow diagram of SAND-2 code are presented, and the analytical code for estimating damage, which is determined with a damage function and a neutron spectrum, is explained. The application of the irradiation damage analysis system using a damage function was carried out to the core support structure of a fast breeder reactor for the damage estimation and the uncertainty evaluation. The fundamental analytical conditions and the analytical model for this work are presented, then the irradiation data for SUS304, the initial estimated values of a damage function, the error analysis for a damage function and the analytical results are explained concerning the computation of a damage function for 10% total elongation. Concerning the damage estimation of FBR core support structure, the standard and lower limiting values of damage, the permissible neutron flux and the allowable years of reactor operation are presented and were evaluated. (Nakai, Y.)

Gas turbine engine turbine blade damaging estimate in maintenance

Directory of Open Access Journals (Sweden)

Ель-Хожайрі Хусейн

2004-01-01

Full Text Available  The factors determining character and intensity of corrosive damages of gas turbine blades are analyzed in the article. The classification of detrimental impurities polluting gas turbine airflow duct and injuring blade erosion damages are given. Common features of the method of turbine blade corrosive damage estimation are shown in the article.

Aging of hematopoietic stem cells: DNA damage and mutations?

Science.gov (United States)

Moehrle, Bettina M; Geiger, Hartmut

2016-10-01

Aging in the hematopoietic system and the stem cell niche contributes to aging-associated phenotypes of hematopoietic stem cells (HSCs), including leukemia and aging-associated immune remodeling. Among others, the DNA damage theory of aging of HSCs is well established, based on the detection of a significantly larger amount of γH2AX foci and a higher tail moment in the comet assay, both initially thought to be associated with DNA damage in aged HSCs compared with young cells, and bone marrow failure in animals devoid of DNA repair factors. Novel data on the increase in and nature of DNA mutations in the hematopoietic system with age, the quality of the DNA damage response in aged HSCs, and the nature of γH2AX foci question a direct link between DNA damage and the DNA damage response and aging of HSCs, and rather favor changes in epigenetics, splicing-factors or three-dimensional architecture of the cell as major cell intrinsic factors of HSCs aging. Aging of HSCs is also driven by a strong contribution of aging of the niche. This review discusses the DNA damage theory of HSC aging in the light of these novel mechanisms of aging of HSCs. Copyright © 2016 ISEH - International Society for Experimental Hematology. Published by Elsevier Inc. All rights reserved.

Protective effects of vitamin C against gamma-ray induced wholly damage and genetic damage

International Nuclear Information System (INIS)

Fu Chunling; Jiang Weiwei; Zhang Ping; Chen Xiang; Zhu Shengtao

2000-01-01

Objective: Protective effects of supplemental vitamin C against 60 Co-gamma-ray induced wholly damage and genetic damage was investigated in mice. Method: Mice were divided into normal control group, irradiation control group and vitamin C experimental group 1,2,3 (which were orally given vitamin C 15, 30, 45 mg/kg.bw for 10 successive days respectively prior to gamma-ray irradiation). Micronuclei in the bone marrow polychromatophilic erythrocytes in each group of mice were examined and the 30 day survival rate of mice following whole-body 5.0 Gy γ irradiation were also determined. Results: Supplemental vitamin C prior to gamma-rays irradiation can significantly decrease bone marrow PECMN rate of mice and increase 30 day survival rate and prolong average survival time. The protection factor is 2.09. Conclusion: Vitamin C has potent protective effects against gamma irradiation induced damage in mice. In certain dose range, vitamin C can absolutely suppress the gamma-rays induced genetic damage in vivo

Large area damage testing of optics

International Nuclear Information System (INIS)

Sheehan, L.; Kozlowski, M.; Stolz, C.

1996-01-01

The damage threshold specifications for the National Ignition Facility will include a mixture of standard small-area tests and new large-area tests. During our studies of laser damage and conditioning processes of various materials we have found that some damage morphologies are fairly small and this damage does not grow with further illumination. This type of damage might not be detrimental to the laser performance. We should therefore assume that some damage can be allowed on the optics, but decide on a maximum damage allowance of damage. A new specification of damage threshold termed open-quotes functional damage thresholdclose quotes was derived. Further correlation of damage size and type to system performance must be determined in order to use this measurement, but it is clear that it will be a large factor in the optics performance specifications. Large-area tests have verified that small-area testing is not always sufficient when the optic in question has defect-initiated damage. This was evident for example on sputtered polarizer and mirror coatings where the defect density was low enough that the features could be missed by standard small- area testing. For some materials, the scale-length at which damage non-uniformities occur will effect the comparison of small-area and large-area tests. An example of this was the sub-aperture tests on KD*P crystals on the Beamlet test station. The tests verified the large-area damage threshold to be similar to that found when testing a small-area. Implying that for this KD*P material, the dominate damage mechanism is of sufficiently small scale-length that small-area testing is capable of determining the threshold. The Beamlet test station experiments also demonstrated the use of on-line laser conditioning to increase the crystals damage threshold

Factors influencing heterogeneity of radiation-induced DNA-damage measured by the alkaline comet assay

International Nuclear Information System (INIS)

Seidel, Clemens; Lautenschläger, Christine; Dunst, Jürgen; Müller, Arndt-Christian

2012-01-01

To investigate whether different conditions of DNA structure and radiation treatment could modify heterogeneity of response. Additionally to study variance as a potential parameter of heterogeneity for radiosensitivity testing. Two-hundred leukocytes per sample of healthy donors were split into four groups. I: Intact chromatin structure; II: Nucleoids of histone-depleted DNA; III: Nucleoids of histone-depleted DNA with 90 mM DMSO as antioxidant. Response to single (I-III) and twice (IV) irradiation with 4 Gy and repair kinetics were evaluated using %Tail-DNA. Heterogeneity of DNA damage was determined by calculation of variance of DNA-damage (V) and mean variance (Mvar), mutual comparisons were done by one-way analysis of variance (ANOVA). Heterogeneity of initial DNA-damage (I, 0 min repair) increased without histones (II). Absence of histones was balanced by addition of antioxidants (III). Repair reduced heterogeneity of all samples (with and without irradiation). However double irradiation plus repair led to a higher level of heterogeneity distinguishable from single irradiation and repair in intact cells. Increase of mean DNA damage was associated with a similarly elevated variance of DNA damage (r = +0.88). Heterogeneity of DNA-damage can be modified by histone level, antioxidant concentration, repair and radiation dose and was positively correlated with DNA damage. Experimental conditions might be optimized by reducing scatter of comet assay data by repair and antioxidants, potentially allowing better discrimination of small differences. Amount of heterogeneity measured by variance might be an additional useful parameter to characterize radiosensitivity

Durability of Flexible Ureteroscopes: A Prospective Evaluation of Longevity, the Factors that Affect it, and Damage Mechanisms.

Science.gov (United States)

Legemate, Jaap D; Kamphuis, Guido M; Freund, Jan Erik; Baard, Joyce; Zanetti, Stefano P; Catellani, Michele; Oussoren, Harry W; de la Rosette, Jean J

2018-03-10

Flexible ureteroscopy is an established treatment modality for evaluating and treating abnormalities in the upper urinary tract. Reusable ureteroscope (USC) durability is a significant concern. To evaluate the durability of the latest generation of digital and fiber optic reusable flexible USCs and the factors affecting it. Six new flexible USCs from Olympus and Karl Storz were included. The primary endpoint for each USC was its first repair. Data on patient and treatment characteristics, accessory device use, ureteroscopy time, image quality, USC handling, disinfection cycles, type of damage, and deflection loss were collected prospectively. Ureteroscopy. USC durability was measured as the total number of uses and ureteroscopy time before repair. USC handling and image quality were scored. After every procedure, maximal ventral and dorsal USC deflection were documented on digital images. A total of 198 procedures were performed. The median number of procedures was 27 (IQR 16-48; 14h) for the six USCs overall, 27 (IQR 20-56; 14h) for the digital USCs, and 24 (range 10-37; 14h) for the fiber optic USCs. Image quality remained high throughout the study for all six USCs. USC handling and the range of deflection remained good under incremental use. Damage to the distal part of the shaft and shaft coating was the most frequent reason for repair, and was related to intraoperative manual forcing. A limitation of this study is its single-center design. The durability of the latest reusable flexible USCs in the current study was limited to 27 uses (14h). Damage to the flexible shaft was the most important limitation to the durability of the USCs evaluated. Prevention of intraoperative manual forcing of flexible USCs maximizes their overall durability. Current flexible ureteroscopes proved to be durable. Shaft vulnerability was the most important limiting factor affecting durability. Copyright © 2018 European Association of Urology. Published by Elsevier B.V. All rights

Drivers of flood damage on event level

DEFF Research Database (Denmark)

Kreibich, H.; Aerts, J. C. J. H.; Apel, H.

2016-01-01

Flood risk is dynamic and influenced by many processes related to hazard, exposure and vulnerability. Flood damage increased significantly over the past decades, however, resulting overall economic loss per event is an aggregated indicator and it is difficult to attribute causes to this increasing...... trend. Much has been learned about damaging processes during floods at the micro-scale, e.g. building level. However, little is known about the main factors determining the amount of flood damage on event level. Thus, we analyse and compare paired flood events, i.e. consecutive, similar damaging floods...... example are the 2002 and 2013 floods in the Elbe and Danube catchments in Germany. The 2002 flood caused the highest economic damage (EUR 11600 million) due to a natural hazard event in Germany. Damage was so high due to extreme flood hazard triggered by extreme precipitation and a high number...

Micromechanics based framework with second-order damage tensors

Science.gov (United States)

Desmorat, R.; Desmorat, B.; Olive, M.; Kolev, B.

2018-05-01

The harmonic product of tensors---leading to the concept of harmonic factorization---has been defined in a previous work (Olive et al, 2017). In the practical case of 3D crack density measurements on thin or thick walled structures, this mathematical tool allows us to factorize the harmonic (irreducible) part of the fourth-order damage tensor as an harmonic square: an exact harmonic square in 2D, an harmonic square over the set of so-called mechanically accessible directions for measurements in the 3D case. The corresponding micro-mechanics framework based on second---instead of fourth---order damage tensors is derived. An illustrating example is provided showing how the proposed framework allows for the modeling of the so-called hydrostatic sensitivity up to high damage levels.

Radiographic changes and factors associated with subsequent progression of damage in weight-bearing joints of patients with rheumatoid arthritis under TNF-blocking therapies-three-year observational study.

Science.gov (United States)

Matsushita, Isao; Motomura, Hiraku; Seki, Eiko; Kimura, Tomoatsu

2017-07-01

The long-term effects of tumor necrosis factor (TNF)-blocking therapies on weight-bearing joints in patients with rheumatoid arthritis (RA) have not been fully characterized. The purpose of this study was to assess the radiographic changes of weight-bearing joints in patients with RA during 3-year of TNF-blocking therapies and to identify factors related to the progression of joint damage. Changes in clinical variables and radiological findings in 243 weight-bearing joints (63 hips, 54 knees, 71 ankles, and 55 subtalar joints) in 38 consecutive patients were investigated during three years of treatment with TNF-blocking agents. Multivariate logistic regression analysis was used to identify risk factors for the progression of weight-bearing joint damage. Seventeen (14.5%) of proximal weight-bearing joints (hips and knees) showed apparent radiographic progression during three years of treatment, whereas none of the proximal weight-bearing joints showed radiographic evidence of improvement or repair. In contrast, distal weight-bearing joints (ankle and subtalar joints) displayed radiographic progression and improvement in 20 (15.9%) and 8 (6.3%) joints, respectively. Multivariate logistic analysis for proximal weight-bearing joints identified the baseline Larsen grade (p bearing joints identified disease activity at one year after treatment (p bearing joints. Disease activity after treatment was an independent factor for progression of damage in proximal and distal weight-bearing joints. Early treatment with TNF-blocking agents and tight control of disease activity are necessary to prevent the progression of damage of the weight-bearing joints.

3D Progressive Damage Modeling for Laminated Composite Based on Crack Band Theory and Continuum Damage Mechanics

Science.gov (United States)

Wang, John T.; Pineda, Evan J.; Ranatunga, Vipul; Smeltzer, Stanley S.

2015-01-01

A simple continuum damage mechanics (CDM) based 3D progressive damage analysis (PDA) tool for laminated composites was developed and implemented as a user defined material subroutine to link with a commercially available explicit finite element code. This PDA tool uses linear lamina properties from standard tests, predicts damage initiation with an easy-to-implement Hashin-Rotem failure criteria, and in the damage evolution phase, evaluates the degradation of material properties based on the crack band theory and traction-separation cohesive laws. It follows Matzenmiller et al.'s formulation to incorporate the degrading material properties into the damaged stiffness matrix. Since nonlinear shear and matrix stress-strain relations are not implemented, correction factors are used for slowing the reduction of the damaged shear stiffness terms to reflect the effect of these nonlinearities on the laminate strength predictions. This CDM based PDA tool is implemented as a user defined material (VUMAT) to link with the Abaqus/Explicit code. Strength predictions obtained, using this VUMAT, are correlated with test data for a set of notched specimens under tension and compression loads.

Factors influencing heterogeneity of radiation-induced DNA-damage measured by the alkaline comet assay

Directory of Open Access Journals (Sweden)

Seidel Clemens

2012-04-01

Full Text Available Abstract Background To investigate whether different conditions of DNA structure and radiation treatment could modify heterogeneity of response. Additionally to study variance as a potential parameter of heterogeneity for radiosensitivity testing. Methods Two-hundred leukocytes per sample of healthy donors were split into four groups. I: Intact chromatin structure; II: Nucleoids of histone-depleted DNA; III: Nucleoids of histone-depleted DNA with 90 mM DMSO as antioxidant. Response to single (I-III and twice (IV irradiation with 4 Gy and repair kinetics were evaluated using %Tail-DNA. Heterogeneity of DNA damage was determined by calculation of variance of DNA-damage (V and mean variance (Mvar, mutual comparisons were done by one-way analysis of variance (ANOVA. Results Heterogeneity of initial DNA-damage (I, 0 min repair increased without histones (II. Absence of histones was balanced by addition of antioxidants (III. Repair reduced heterogeneity of all samples (with and without irradiation. However double irradiation plus repair led to a higher level of heterogeneity distinguishable from single irradiation and repair in intact cells. Increase of mean DNA damage was associated with a similarly elevated variance of DNA damage (r = +0.88. Conclusions Heterogeneity of DNA-damage can be modified by histone level, antioxidant concentration, repair and radiation dose and was positively correlated with DNA damage. Experimental conditions might be optimized by reducing scatter of comet assay data by repair and antioxidants, potentially allowing better discrimination of small differences. Amount of heterogeneity measured by variance might be an additional useful parameter to characterize radiosensitivity.

A ChIP-chip approach reveals a novel role for transcription factor IRF1 in the DNA damage response.

Science.gov (United States)

Frontini, Mattia; Vijayakumar, Meeraa; Garvin, Alexander; Clarke, Nicole

2009-03-01

IRF1 is a transcription factor that regulates key processes in the immune system and in tumour suppression. To gain further insight into IRF1's role in these processes, we searched for new target genes by performing chromatin immunoprecipitation coupled to a CpG island microarray (ChIP-chip). Using this approach we identified 202 new IRF1-binding sites with high confidence. Functional categorization of the target genes revealed a surprising cadre of new roles that can be linked to IRF1. One of the major functional categories was the DNA damage response pathway. In order to further validate our findings, we show that IRF1 can regulate the mRNA expression of a number of the DNA damage response genes in our list. In particular, we demonstrate that the mRNA and protein levels of the DNA repair protein BRIP1 [Fanconi anemia gene J (FANC J)] are upregulated after IRF1 over-expression. We also demonstrate that knockdown of IRF1 by siRNA results in loss of BRIP1 expression, abrogation of BRIP1 foci after DNA interstrand crosslink (ICL) damage and hypersensitivity to the DNA crosslinking agent, melphalan; a characteristic phenotype of FANC J cells. Taken together, our data provides a more complete understanding of the regulatory networks controlled by IRF1 and reveals a novel role for IRF1 in regulating the ICL DNA damage response.

A ChIP–chip approach reveals a novel role for transcription factor IRF1 in the DNA damage response

Science.gov (United States)

Frontini, Mattia; Vijayakumar, Meeraa; Garvin, Alexander; Clarke, Nicole

2009-01-01

IRF1 is a transcription factor that regulates key processes in the immune system and in tumour suppression. To gain further insight into IRF1's role in these processes, we searched for new target genes by performing chromatin immunoprecipitation coupled to a CpG island microarray (ChIP–chip). Using this approach we identified 202 new IRF1-binding sites with high confidence. Functional categorization of the target genes revealed a surprising cadre of new roles that can be linked to IRF1. One of the major functional categories was the DNA damage response pathway. In order to further validate our findings, we show that IRF1 can regulate the mRNA expression of a number of the DNA damage response genes in our list. In particular, we demonstrate that the mRNA and protein levels of the DNA repair protein BRIP1 [Fanconi anemia gene J (FANC J)] are upregulated after IRF1 over-expression. We also demonstrate that knockdown of IRF1 by siRNA results in loss of BRIP1 expression, abrogation of BRIP1 foci after DNA interstrand crosslink (ICL) damage and hypersensitivity to the DNA crosslinking agent, melphalan; a characteristic phenotype of FANC J cells. Taken together, our data provides a more complete understanding of the regulatory networks controlled by IRF1 and reveals a novel role for IRF1 in regulating the ICL DNA damage response. PMID:19129219

DNA damage in neurodegenerative diseases

Energy Technology Data Exchange (ETDEWEB)

Coppedè, Fabio, E-mail: fabio.coppede@med.unipi.it; Migliore, Lucia, E-mail: lucia.migliore@med.unipi.it

2015-06-15

Highlights: • Oxidative DNA damage is one of the earliest detectable events in the neurodegenerative process. • The mitochondrial DNA is more vulnerable to oxidative attack than the nuclear DNA. • Cytogenetic damage has been largely documented in Alzheimer's disease patients. • The question of whether DNA damage is cause or consequence of neurodegeneration is still open. • Increasing evidence links DNA damage and repair with epigenetic phenomena. - Abstract: Following the observation of increased oxidative DNA damage in nuclear and mitochondrial DNA extracted from post-mortem brain regions of patients affected by neurodegenerative diseases, the last years of the previous century and the first decade of the present one have been largely dedicated to the search of markers of DNA damage in neuronal samples and peripheral tissues of patients in early, intermediate or late stages of neurodegeneration. Those studies allowed to demonstrate that oxidative DNA damage is one of the earliest detectable events in neurodegeneration, but also revealed cytogenetic damage in neurodegenerative conditions, such as for example a tendency towards chromosome 21 malsegregation in Alzheimer's disease. As it happens for many neurodegenerative risk factors the question of whether DNA damage is cause or consequence of the neurodegenerative process is still open, and probably both is true. The research interest in markers of oxidative stress was shifted, in recent years, towards the search of epigenetic biomarkers of neurodegenerative disorders, following the accumulating evidence of a substantial contribution of epigenetic mechanisms to learning, memory processes, behavioural disorders and neurodegeneration. Increasing evidence is however linking DNA damage and repair with epigenetic phenomena, thereby opening the way to a very attractive and timely research topic in neurodegenerative diseases. We will address those issues in the context of Alzheimer's disease

DNA damage in neurodegenerative diseases

International Nuclear Information System (INIS)

Coppedè, Fabio; Migliore, Lucia

2015-01-01

Highlights: • Oxidative DNA damage is one of the earliest detectable events in the neurodegenerative process. • The mitochondrial DNA is more vulnerable to oxidative attack than the nuclear DNA. • Cytogenetic damage has been largely documented in Alzheimer's disease patients. • The question of whether DNA damage is cause or consequence of neurodegeneration is still open. • Increasing evidence links DNA damage and repair with epigenetic phenomena. - Abstract: Following the observation of increased oxidative DNA damage in nuclear and mitochondrial DNA extracted from post-mortem brain regions of patients affected by neurodegenerative diseases, the last years of the previous century and the first decade of the present one have been largely dedicated to the search of markers of DNA damage in neuronal samples and peripheral tissues of patients in early, intermediate or late stages of neurodegeneration. Those studies allowed to demonstrate that oxidative DNA damage is one of the earliest detectable events in neurodegeneration, but also revealed cytogenetic damage in neurodegenerative conditions, such as for example a tendency towards chromosome 21 malsegregation in Alzheimer's disease. As it happens for many neurodegenerative risk factors the question of whether DNA damage is cause or consequence of the neurodegenerative process is still open, and probably both is true. The research interest in markers of oxidative stress was shifted, in recent years, towards the search of epigenetic biomarkers of neurodegenerative disorders, following the accumulating evidence of a substantial contribution of epigenetic mechanisms to learning, memory processes, behavioural disorders and neurodegeneration. Increasing evidence is however linking DNA damage and repair with epigenetic phenomena, thereby opening the way to a very attractive and timely research topic in neurodegenerative diseases. We will address those issues in the context of Alzheimer's disease

Smoke damages of forest from the biologic standpoint

Energy Technology Data Exchange (ETDEWEB)

Kisser, J

1966-01-01

Biological aspects of smoke damages are reviewed with special regard to forests. Due to the long exposures, smoke is more harmful to forests than to farm plants. Invisible physiological damages due to protoplasm lesions are counteracted by the regenerative effect of certain enzyme systems. Insoluble solid emissions reduce both light and assimilation, while soluble particles may penetrate into the plant or the soil, causing changes in the vegetation. Damage caused by soot and photochemical smog are detailed. Sulfur dioxide and hydrofluoric acid are two basic gaseous pollutants damaging forests. The importance of the damage is primarily determined by concentration and duration of exposure, with emphasis on concentration. In high concentrations, the substances are dissolved in the mesophyll cell wall fluid, causing point-like necroses. Low concentrations lead to necroses on the ends and edges of leaves and needles. The damages are also influenced by climatic factors. The transpiration and consequently the sensitivity for SO/sub 2/ are dependent of the relative humidity. Sharp increase in sensitivity can be observed from 60% to 90% relative humidity. There is no direct connection between transpiration rate and assimilation performance. High transpiration coefficients are characteristic of dry climates. There is no relation between transpiration and sensitivity, while any factor affecting the cuticular openings influences the extent of the damage. The resistance to smoke cannot be improved in forests by means of fertilizers. Different resistances of various species as well as problems of breeding smoke-resistant species are discussed.

Preterm newborns show slower repair of oxidative damage and paternal smoking associated DNA damage.

Science.gov (United States)

Vande Loock, Kim; Ciardelli, Roberta; Decordier, Ilse; Plas, Gina; Haumont, Dominique; Kirsch-Volders, Micheline

2012-09-01

Newborns have to cope with hypoxia during delivery and a sudden increase in oxygen at birth. Oxygen will partly be released as reactive oxygen species having the potential to cause damage to DNA and proteins. In utero, increase of most (non)-enzymatic antioxidants occurs during last weeks of gestation, making preterm neonates probably more sensitive to oxidative stress. Moreover, it has been hypothesized that oxidative stress might be the common etiological factor for certain neonatal diseases in preterm infants. The aim of this study was to assess background DNA damage; in vitro H(2)O(2) induced oxidative DNA damage and repair capacity (residual DNA damage) in peripheral blood mononucleated cells from 25 preterm newborns and their mothers. In addition, demographic data were taken into account and repair capacity of preterm was compared with full-term newborns. Multivariate linear regression analysis revealed that preterm infants from smoking fathers have higher background DNA damage levels than those from non-smoking fathers, emphasizing the risk of paternal smoking behaviour for the progeny. Significantly higher residual DNA damage found after 15-min repair in preterm children compared to their mothers and higher residual DNA damage after 2 h compared to full-term newborns suggest a slower DNA repair capacity in preterm children. In comparison with preterm infants born by caesarean delivery, preterm infants born by vaginal delivery do repair more slowly the in vitro induced oxidative DNA damage. Final impact of passive smoking and of the slower DNA repair activity of preterm infants need to be confirmed in a larger study population combining transgenerational genetic and/or epigenetic effects, antioxidant levels, genotypes, repair enzyme efficiency/levels and infant morbidity.

Metabolite Damage and Metabolite Damage Control in Plants

Energy Technology Data Exchange (ETDEWEB)

Hanson, Andrew D. [Horticultural Sciences Department and; Henry, Christopher S. [Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, Illinois 60439, email:; Computation Institute, University of Chicago, Chicago, Illinois 60637; Fiehn, Oliver [Genome Center, University of California, Davis, California 95616, email:; de Crécy-Lagard, Valérie [Microbiology and Cell Science Department, University of Florida, Gainesville, Florida 32611, email: ,

2016-04-29

It is increasingly clear that (a) many metabolites undergo spontaneous or enzyme-catalyzed side reactions in vivo, (b) the damaged metabolites formed by these reactions can be harmful, and (c) organisms have biochemical systems that limit the buildup of damaged metabolites. These damage-control systems either return a damaged molecule to its pristine state (metabolite repair) or convert harmful molecules to harmless ones (damage preemption). Because all organisms share a core set of metabolites that suffer the same chemical and enzymatic damage reactions, certain damage-control systems are widely conserved across the kingdoms of life. Relatively few damage reactions and damage-control systems are well known. Uncovering new damage reactions and identifying the corresponding damaged metabolites, damage-control genes, and enzymes demands a coordinated mix of chemistry, metabolomics, cheminformatics, biochemistry, and comparative genomics. This review illustrates the above points using examples from plants, which are at least as prone to metabolite damage as other organisms.

Fatigue-Damage Estimation and Control for Wind Turbines

OpenAIRE

Barradas Berglind, Jose de Jesus

2015-01-01

How can fatigue-damage for control of wind turbines be represented? Fatigue-damage is indeed a crucial factor in structures such as wind turbines that are exposed to turbulent and rapidly changing wind flow conditions. This is relevant both in their design stage and during the control of their operation. Accordingly, the most recognized methods of fatigue-damage estimation are discussed in this thesis.In wind energy conversion systems there is an intrinsic trade-off between power generation m...

Damage assessment in Braunsbach 2016: data collection and analysis for an improved understanding of damaging processes during flash floods

Science.gov (United States)

Laudan, Jonas; Rözer, Viktor; Sieg, Tobias; Vogel, Kristin; Thieken, Annegret H.

2017-12-01

Flash floods are caused by intense rainfall events and represent an insufficiently understood phenomenon in Germany. As a result of higher precipitation intensities, flash floods might occur more frequently in future. In combination with changing land use patterns and urbanisation, damage mitigation, insurance and risk management in flash-flood-prone regions are becoming increasingly important. However, a better understanding of damage caused by flash floods requires ex post collection of relevant but yet sparsely available information for research. At the end of May 2016, very high and concentrated rainfall intensities led to severe flash floods in several southern German municipalities. The small town of Braunsbach stood as a prime example of the devastating potential of such events. Eight to ten days after the flash flood event, damage assessment and data collection were conducted in Braunsbach by investigating all affected buildings and their surroundings. To record and store the data on site, the open-source software bundle KoBoCollect was used as an efficient and easy way to gather information. Since the damage driving factors of flash floods are expected to differ from those of riverine flooding, a post-hoc data analysis was performed, aiming to identify the influence of flood processes and building attributes on damage grades, which reflect the extent of structural damage. Data analyses include the application of random forest, a random general linear model and multinomial logistic regression as well as the construction of a local impact map to reveal influences on the damage grades. Further, a Spearman's Rho correlation matrix was calculated. The results reveal that the damage driving factors of flash floods differ from those of riverine floods to a certain extent. The exposition of a building in flow direction shows an especially strong correlation with the damage grade and has a high predictive power within the constructed damage models. Additionally

Ciliary derived neurotrophic factor protects oligodendrocytes against radiation induced damage in vitro by a mechanism independent of a proliferative effect

International Nuclear Information System (INIS)

Evans, Andrew J.; Mabie, Peter C.; Kessler, Jack A.; Vikram, Bhadrasain

1997-01-01

Purpose/Objective: Radiation-induced damage to the central nervous system in the from of myelopathy is a dose-limiting complication in the treatment of tumors situated in or close to the spinal cord. The target cell for this damage is not definitively identified, but demyelination due to oligodendrocyte damage is strongly implicated. Multiple neurotrophic factors have recently been identified which demonstrate a survival effect on oligodendrocytes. We investigated the effect of Ciliary Derived Neurotrophic Factor (CNTF), Neurotrophin-3 (NT-3) and Nerve Growth Factor (NGF) on the radiosensitivity of oligodendrocytes in vitro to determine if this may ameliorate radiation damage, as a model for reducing myelopathy in vivo. Materials and Methods: Mature oligodendrocytes were cultured from the cortex of newborn Sprague-Dawley white rats and maintained on poly-d-lysine plates. The experimental arm was exposed to CNTF (0.01-100ng/ml), NGF (100ng/ml) or NT-3 (20ng/ml) for 24 hours prior to radiation, and control and experimental arms radiated using a cobalt 60 irradiator at a dose rate of .87 Gy/min with doses from 2 Gy to 10 Gy. Oligodendrocytes were identified using an O4 antibody, assessed for viability at 5 days using an MTT assay and counted using a phase contrast microscope. Combination studies of CNTF and NT-3 were also performed. BrdU studies were performed to determine if the various neurotrophins induced proliferation, with BrdU added for the 24 hour period prior to radiation only, for the 5 day period following radiation only, or for both periods combined. Results: The proportion of mature oligodendrocytes surviving 5 days after irradiation was not significantly increased by NGF, and was only modestly increased by NT-3. However, CNTF significantly increased the surviving proportion at all doses The addition of NT-3 to CNTF did not further increase the proportion of oligodendrocytes surviving. CNTF dose escalation studies confirmed 20ng/ml as an optimal dose. Brd

Effect of site conditions on ground motion and damage

Science.gov (United States)

Borcherdt, R.; Glassmoyer, G.; Andrews, M.; Cranswick, E.

1989-01-01

Results of seismologic studies conducted by the U.S. reconnaissance team in conjunction with Soviet colleagues following the tragic earthquakes of December 7, 1988, suggest that site conditions may have been a major factor in contributing to increased damage levels in Leninakan. As the potential severity of these effects in Leninakan had not been previously identified, this chapter presents results intended to provide a preliminary quantification of these effects on both damage and levels of ground motion observed in Leninakan. The article describes the damage distribution geologic setting, ground motion amplification in Leninakan, including analog amplifications and spectral amplifications. Preliminary model estimates for site response are presented. It is concluded that ground motion amplification in the 0.5-2.5-second period range was a major contributing factor to increased damage in Leninakan as compared with Kirovakan. Leninakan is located on thick water saturated alluvial deposits.

Strategic petroleum reserve caverns casing damage update 1997

Energy Technology Data Exchange (ETDEWEB)

Munson, D.E.; Molecke, M.A.; Neal, J.T. [and others

1998-01-01

Hanging casing strings are used for oil and brine transfer in the domal salt storage caverns of the Strategic Petroleum Reserve (SPR). Damage to these casings is of concern because hanging string replacement is costly and because of implications on cavern stability. Although the causes of casing damage are not always well defined, many events leading to damage are assumed to be the result of salt falls impacting the hanging strings. However, in some cases, operational aspects may be suspected. The history of damage to hanging strings is updated in this study to include the most recent events. Potential general domal and local operational and material factors that could influence the tendency for caverns to have salt falls are examined in detail. As a result of this examination, general factors, such as salt dome anomalies and crude type, and most of the operational factors, such as geometry, location and depressurizations, are not believed to be primary causes of casing damage. Further analysis is presented of the accumulation of insolubles during cavern solutioning and accumulation of salt fall material on the cavern floor. Inaccuracies in sump geometry probably make relative cavern insolubles contents uncertain. However, determination of the salt fall accumulations, which are more accurate, suggest that the caverns with the largest salt fall accumulations show the greatest number of hanging string events. There is good correlation between the accumulation rate and the number of events when the event numbers are corrected to an equivalent number for a single hanging string in a quiescent, operating cavern. The principal factor that determines the propensity for a cavern to exhibit this behavior is thought to be the effect of impurity content on the fracture behavior of salt.

An economic approach to 'losses and damages'

International Nuclear Information System (INIS)

Roulleau, Thomas

2015-01-01

Given ever more greenhouse gas emissions, developing countries have recently placed the issue of 'losses and damages' on the bargaining table. The losses and damages ensuing from climate catastrophes depend on factors that are both planetary (extreme meteorological phenomena wherein climate change is a factor) and domestic (the exposure and vulnerability of populations). The Warsaw International Mechanism for Loss and Damage Associated with Climate Change Impacts was set up in 2013. Several developing countries are demanding that it become autonomous with its own funding. This demand does not seem justified scientifically or economically in the current context. Although economic losses owing to climate-related catastrophes have increased in recent decades, they are, as scientific studies have shown, due to increases in wealth and in the population's exposure and not to climate change as such. Furthermore, the aforementioned funding mechanism risks impeding efficient domestic actions for reducing a country's vulnerability and its population's exposure to climate-related risks

Lattice damage in ion-implanted silicon-germanium alloys

International Nuclear Information System (INIS)

Haynes, T.E.; Holland, O.W.

1992-08-01

The damage produced in Si 1-x Ge x alloys (0≤x≤1) by implantation of 70--100 keV 30 Si + has been measured as a function of temperature and fluence by ion channeling. For all compositions, the damage efficiency decreased sharply as the implant temperature was increased between room temperature and 150 degrees C. Furthermore, the damage efficiency in alloys of intermediate compositions (0.34≤x≤0.5) exceeds that in Ge, especially at elevated temperatures, despite the larger cascade energy density in Ge. It is shown that this behavior can be described based on a model in which the point-defect mobility is the dominant factor controlling damage retention, rather than the cascade energy density. This approach provides a framework for understanding other temperature-dependent phenomena related to damage growth in Si-Ge alloys including dose-rate effects and damage saturation in MeV implantation

Correlation of DT and DD fusion neutron damage in silicon surface barrier detector

International Nuclear Information System (INIS)

Iida, Toshiyuki; Sueyoshi, Yasuhiro; Sunarno; Takahashi, Akito

1994-01-01

In order to examine the correlation of DT and DD fusion neutron damage in Si, a silicon surface barrier detector (Si-SBD) was irradiation with neutrons from a deuteron accelerator. The leakage current increased proportionally with neutron fluence, which determined the neutron damage constant for the Si-SBD. The correlation factor of the DT and DD neutron damage in the Si-SBD was determined from the ratio of the DT and DD neutron damage constants and was found to be 2.3. We also calculated the rate of DT and DD neutron displacement damage for Si by using the TRIM-90 computer program and actual data on neutron reactions in the Si-SBD. The correlation factor of DT and DD neutron damage from the calculation agreed with that from the Si-SBD irradiation experiment. (author)

Radiation-induced DNA damage in tumors and normal tissues. II. Influence of dose, residual DNA damage and physiological factors in oxygenated cells

International Nuclear Information System (INIS)

Zhang, H.; Wheeler, K.T.

1994-01-01

Detection and quantification of hypoxic cells in solid tumors is important for many experimental and clinical situations. Several laboratories, including ours, have suggested that assays which measure radiation-induced DNA strand breaks and DNA-protein crosslinks (DPCs) might be used to detect or quantify hypoxic cells in tumors and normal tissues. Recently, we demonstrated the feasibility of using an alkaline elution assay that measures strand breaks and DPCs to detect and/or quantify hypoxic cells in tissues. For this approach to be valid, DPCs must not be formed to any great extent in irradiated oxygenated cells, and the formation and repair of strand breaks and DPCs in oxygenated cells must not be modified appreciably by physiological factors (e.g., temperature, pH and nutrient depletion) that are often found in solid tumors. To address these issues, two sets of experiments were performed. In one set of experiments, oxygenated 9L cells in tissue culture, subcutaneous 9L tumors and rat cerebella were irradiated with doses of 15 or 50 Gy and allowed to repair until the residual strand break damage was low enough to detect DPCs. In another set of experiments, oxygenated exponentially growing or plateau-phase 9L cells in tissue culture were irradiated with a dose of 15 Gy at 37 or 20 degrees C, while the cells were maintained at a pH of either 6.6 or 7.3. DNA-protein crosslinks were formed in oxygenated cells about 100 times less efficiently than in hypoxic cells. In addition, temperature, pH, nutrient depletion and growth phase did not appreciably alter the formation and repair of strand breaks or the formation of DPCs in oxygenated 9L cells. These results support the use of this DNA damage assay for the detection and quantification of hypoxic cells in solid tumors. 27 refs., 5 tabs

DNA damage in the oocytes SACs

Czech Academy of Sciences Publication Activity Database

Macůrek, Libor

2016-01-01

Roč. 15, č. 4 (2016), s. 491-492 ISSN 1538-4101 Institutional support: RVO:68378050 Keywords : DNA damage response * oocyte * meiosis * checkpoint Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.530, year: 2016

Creep damage index as a sensitive indicator of damage accumulation in thermoplastic laminates

Czech Academy of Sciences Publication Activity Database

Minster, Jiří; Šperl, Martin; Šepitka, J.

2018-01-01

Roč. 37, č. 3 (2018), s. 147-154 ISSN 0731-6844 Institutional support: RVO:68378297 Keywords : damage accumulation * thermoplastic laminate * cyclic tensile loading * time-dependent properties * microindentation Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis Impact factor: 1.086, year: 2016 http://journals.sagepub.com/doi/pdf/10.1177/0731684417735184

Radiation-induced liver damage

International Nuclear Information System (INIS)

Marcial, V.A.; Santiago-Delpin, E.A.; Lanaro, A.E.; Castro-Vita, H.; Arroyo, G.; Moscol, J.A.; Gomez, C.; Velazquez, J.; Prado, K.

1977-01-01

Due to the recent increase in the use of radiation therapy in the treatment of cancer with or without chemotherapy, the risk of liver radiation damage has become a significant concern for the radiotherapist when the treated tumour is located in the upper abdomen or lower thorax. Clinically evident radiation liver damage may result in significant mortality, but at times patients recover without sequelae. The dose of 3000 rads in 3 weeks to the entire liver with 5 fractions per week of 200 rads each, seems to be tolerated well clinically by adult humans. Lower doses may lead to damage when used in children, when chemotherapy is added, as in recent hepatectomy cases, and in the presence of pre-existent liver damage. Reduced fractionation may lead to increased damage. Increased fractionation, limitation of the dose delivered to the entire liver, and restriction of the high dose irradiation volume may afford protection. With the aim of studying the problems of hepatic radiation injury in humans, a project of liver irradiation in the dog is being conducted. Mongrel dogs are being conditioned, submitted to pre-irradiation studies (haemogram, blood chemistry, liver scan and biopsy), irradiated under conditions resembling human cancer therapy, and submitted to post-irradiation evaluation of the liver. Twenty-two dogs have been entered in the study but only four qualify for the evaluation of all the study parameters. It has been found that dogs are susceptible to liver irradiation damage similar to humans. The initial mortality has been high mainly due to non-radiation factors which are being kept under control at the present phase of the study. After the initial experiences, the study will involve variations in total dose and fractionation, and the addition of anticoagulant therapy for possible prevention of radiation liver injury. (author)

Predicting severe winter coastal storm damage

International Nuclear Information System (INIS)

Hondula, David M; Dolan, Robert

2010-01-01

Over the past 40 years residents of, and visitors to, the North Carolina coastal barrier islands have experienced the destructive forces of several 'named' extratropical storms. These storms have caused large-scale redistributions of sand and loss of coastal structures and infrastructure. While most of the population living on the islands are familiar with the wintertime storms, the damage and scars of the 'super northeasters'-such as the Ash Wednesday storm of 7 March 1962, and the Halloween storm of 1989-are slipping away from the public's memory. In this research we compared the damage zones of the 1962 Ash Wednesday storm, as depicted on aerial photographs taken after the storm, with photos taken of the same areas in 2003. With these high-resolution aerial photos we were able to estimate the extent of new development which has taken place along the Outer Banks of North Carolina since 1962. Three damage zones were defined that extend across the islands from the ocean landward on the 1962 aerial photos: (1) the zone of almost total destruction on the seaward edge of the islands where the storm waves break; (2) the zone immediately inland where moderate structural damage occurs during severe storms; and (3) the zone of flood damage at the landward margin of the storm surge and overwash. We considered the rate of coastal erosion, the rate of development, and increases in property values as factors which may contribute to changing the financial risk for coastal communities. In comparing the values of these four factors with the 1962 damage data, we produced a predicted dollar value for storm damage should another storm of the magnitude of the 1962 Ash Wednesday storm occur in the present decade. This model also provides an opportunity to estimate the rate of increase in the potential losses through time as shoreline erosion continues to progressively reduce the buffer between the development and the edge of the sea. Our data suggest that the losses along the North

Predicting severe winter coastal storm damage

Energy Technology Data Exchange (ETDEWEB)

Hondula, David M; Dolan, Robert, E-mail: hondula@virginia.edu [Department of Environmental Sciences, University of Virginia, PO Box 400123, Charlottesville, VA 22903 (United States)

2010-07-15

Over the past 40 years residents of, and visitors to, the North Carolina coastal barrier islands have experienced the destructive forces of several 'named' extratropical storms. These storms have caused large-scale redistributions of sand and loss of coastal structures and infrastructure. While most of the population living on the islands are familiar with the wintertime storms, the damage and scars of the 'super northeasters'-such as the Ash Wednesday storm of 7 March 1962, and the Halloween storm of 1989-are slipping away from the public's memory. In this research we compared the damage zones of the 1962 Ash Wednesday storm, as depicted on aerial photographs taken after the storm, with photos taken of the same areas in 2003. With these high-resolution aerial photos we were able to estimate the extent of new development which has taken place along the Outer Banks of North Carolina since 1962. Three damage zones were defined that extend across the islands from the ocean landward on the 1962 aerial photos: (1) the zone of almost total destruction on the seaward edge of the islands where the storm waves break; (2) the zone immediately inland where moderate structural damage occurs during severe storms; and (3) the zone of flood damage at the landward margin of the storm surge and overwash. We considered the rate of coastal erosion, the rate of development, and increases in property values as factors which may contribute to changing the financial risk for coastal communities. In comparing the values of these four factors with the 1962 damage data, we produced a predicted dollar value for storm damage should another storm of the magnitude of the 1962 Ash Wednesday storm occur in the present decade. This model also provides an opportunity to estimate the rate of increase in the potential losses through time as shoreline erosion continues to progressively reduce the buffer between the development and the edge of the sea. Our data suggest that the

Predicting severe winter coastal storm damage

Science.gov (United States)

Hondula, David M.; Dolan, Robert

2010-07-01

Over the past 40 years residents of, and visitors to, the North Carolina coastal barrier islands have experienced the destructive forces of several 'named' extratropical storms. These storms have caused large-scale redistributions of sand and loss of coastal structures and infrastructure. While most of the population living on the islands are familiar with the wintertime storms, the damage and scars of the 'super northeasters'—such as the Ash Wednesday storm of 7 March 1962, and the Halloween storm of 1989—are slipping away from the public's memory. In this research we compared the damage zones of the 1962 Ash Wednesday storm, as depicted on aerial photographs taken after the storm, with photos taken of the same areas in 2003. With these high-resolution aerial photos we were able to estimate the extent of new development which has taken place along the Outer Banks of North Carolina since 1962. Three damage zones were defined that extend across the islands from the ocean landward on the 1962 aerial photos: (1) the zone of almost total destruction on the seaward edge of the islands where the storm waves break; (2) the zone immediately inland where moderate structural damage occurs during severe storms; and (3) the zone of flood damage at the landward margin of the storm surge and overwash. We considered the rate of coastal erosion, the rate of development, and increases in property values as factors which may contribute to changing the financial risk for coastal communities. In comparing the values of these four factors with the 1962 damage data, we produced a predicted dollar value for storm damage should another storm of the magnitude of the 1962 Ash Wednesday storm occur in the present decade. This model also provides an opportunity to estimate the rate of increase in the potential losses through time as shoreline erosion continues to progressively reduce the buffer between the development and the edge of the sea. Our data suggest that the losses along the

Improving Flood Damage Assessment Models in Italy

Science.gov (United States)

Amadio, M.; Mysiak, J.; Carrera, L.; Koks, E.

2015-12-01

The use of Stage-Damage Curve (SDC) models is prevalent in ex-ante assessments of flood risk. To assess the potential damage of a flood event, SDCs describe a relation between water depth and the associated potential economic damage over land use. This relation is normally developed and calibrated through site-specific analysis based on ex-post damage observations. In some cases (e.g. Italy) SDCs are transferred from other countries, undermining the accuracy and reliability of simulation results. Against this background, we developed a refined SDC model for Northern Italy, underpinned by damage compensation records from a recent flood event. Our analysis considers both damage to physical assets and production losses from business interruptions. While the first is calculated based on land use information, production losses are measured through the spatial distribution of Gross Value Added (GVA). An additional component of the model assesses crop-specific agricultural losses as a function of flood seasonality. Our results show an overestimation of asset damage from non-calibrated SDC values up to a factor of 4.5 for tested land use categories. Furthermore, we estimate that production losses amount to around 6 per cent of the annual GVA. Also, maximum yield losses are less than a half of the amount predicted by the standard SDC methods.

Cavitation damage prediction for the JSNS mercury target vessel

Energy Technology Data Exchange (ETDEWEB)

Naoe, Takashi, E-mail: naoe.takashi@jaea.go.jp; Kogawa, Hiroyuki; Wakui, Takashi; Haga, Katsuhiro; Teshigawara, Makoto; Kinoshita, Hidetaka; Takada, Hiroshi; Futakawa, Masatoshi

2016-01-15

The liquid mercury target system for the Japan Spallation Neutron Source (JSNS) at the Materials and Life science experimental Facility (MLF) in the Japan Proton Accelerator Research Complex (J-PARC) is designed to produce pulsed neutrons. The mercury target vessel in this system, which is made of type 316L stainless steel, is damaged by pressure wave-induced cavitation due to proton beam bombardment. Currently, cavitation damage is considered to be the dominant factor influencing the service life of the target vessel rather than radiation damage. In this study, cavitation damage to the interior surface of the target vessel was predicted on the basis of accumulated damage data from off-beam and on-beam experiments. The predicted damage was compared with the damage observed in a used target vessel. Furthermore, the effect of injecting gas microbubbles on cavitation damage was predicted through the measurement of the acoustic vibration of the target vessel. It was shown that the predicted depth of cavitation damage is reasonably coincident with the observed results. Moreover, it was confirmed that the injection of gas microbubbles had an effect on cavitation damage.

Time-Dependent Damage Investigation of Rock Mass in an In Situ Experimental Tunnel

Science.gov (United States)

Jiang, Quan; Cui, Jie; Chen, Jing

2012-01-01

In underground tunnels or caverns, time-dependent deformation or failure of rock mass, such as extending cracks, gradual rock falls, etc., are a costly irritant and a major safety concern if the time-dependent damage of surrounding rock is serious. To understand the damage evolution of rock mass in underground engineering, an in situ experimental testing was carried out in a large belowground tunnel with a scale of 28.5 m in width, 21 m in height and 352 m in length. The time-dependent damage of rock mass was detected in succession by an ultrasonic wave test after excavation. The testing results showed that the time-dependent damage of rock mass could last a long time, i.e., nearly 30 days. Regression analysis of damage factors defined by wave velocity, resulted in the time-dependent evolutional damage equation of rock mass, which corresponded with logarithmic format. A damage viscoelastic-plastic model was developed to describe the exposed time-dependent deterioration of rock mass by field test, such as convergence of time-dependent damage, deterioration of elastic modules and logarithmic format of damage factor. Furthermore, the remedial measures for damaged surrounding rock were discussed based on the measured results and the conception of damage compensation, which provides new clues for underground engineering design.

Analysis of Ricefield Land Damage in Denpasar City, Bali, Indonesia

Science.gov (United States)

Suyarto, R.; Wiyanti; Dibia, I. N.

2018-02-01

Soil as a natural resource, living area, environmental media, and factors of production including biomass production that supports human life and other living beings must be preserved, on the other hand, uncontrolled biomass production activities can cause soil damage, ultimately can threaten the survival of humans and other living things. Therefore, in order to control soil damage, first must inventories the soil condition data and its damage which then visualised in soil damage potential and soil damage status. The activities of the study are the preparation of a map of the initial soil conditions and the delineation of potentially land degradation distribution. Mapping results are used as work maps for verification on the field to take soil samples and create soil damage status. In general, Denpasar City have soil damage potential at very low, low until medium rate. Soil damage status in Denpasar City generally is low damage of bulk volume, total porosity, soil permeability and electrolyte conductivity which beyond limitation thresholds.

Fatigue-Damage Estimation and Control for Wind Turbines

DEFF Research Database (Denmark)

Barradas Berglind, Jose de Jesus

How can fatigue-damage for control of wind turbines be represented? Fatigue-damage is indeed a crucial factor in structures such as wind turbines that are exposed to turbulent and rapidly changing wind flow conditions. This is relevant both in their design stage and during the control......, the inclusion of fatigue-damage within feedback control loops is of special interest. Four strategies in total are proposed in this work: three for the wind turbine level and one for the wind farm level. On one hand, the three strategies in the turbine level are based on hysteresis operators and strive......-damage estimation in wind turbine components, to the mixed objective operation of wind energy conversion systems, and to the synthesis of control strategies that include hysteresis operators....

Equivalent damage of loads on pavements

CSIR Research Space (South Africa)

Prozzi, JA

2009-05-26

Full Text Available This report describes a new methodology for the determination of Equivalent Damage Factors (EDFs) of vehicles with multiple axle and wheel configurations on pavements. The basic premise of this new procedure is that "equivalent pavement response...

Development of damage functions for high-rise building components

International Nuclear Information System (INIS)

Kustu, O.; Miller, D.D.; Brokken, S.T.

1982-10-01

The component approach for predicting the effects that ground motion from underground nuclear explosions will have on structures involves predicting the damage to each structural and nonstructural component of a building on the basis of the expected local deformation that most affects the damage to the component. This study was conducted to provide the basic data necessary to evaluate the component approach. Available published laboratory test data for various high-rise building components were collected. These data were analyzed statistically to determine damage threshold values and their variabilities, which in turn were used to derive component damage functions. The portion of construction costs attributable to various building components was determined statistically. This information was needed because component damage functions define damage as a percentage of the replacement values of the component, and, in order to calculate the overall building damage factor, the relative cost of each component must be estimated. The feasibility of the component approach to damage prediction is demonstrated. It is recommended that further experimental research directed towards developing an adequate data base of component damage thresholds for all significant building components should be encouraged. Parallel to this effort, detailed damage data from specific buildings damaged in earthquakes should be collected to verify the theoretical procedure

Sunlight-induced DNA damage in human mononuclear cells

DEFF Research Database (Denmark)

Møller, Peter; Wallin, Hakan; Holst, Erik

2002-01-01

of sunlight was comparable to the interindividual variation, indicating that sunlight exposure and the individual's background were the two most important determinants for the basal level of DNA damage. Influence of other lifestyle factors such as exercise, intake of foods, infections, and age could......In this study of 301 blood samples from 21 subjects, we found markedly higher levels of DNA damage (nonpyrimidine dimer types) in the summer than in the winter detected by single-cell gel electrophoresis. The level of DNA damage was influenced by the average daily influx of sunlight ... to blood sampling. The 3 and 6 day periods before sampling influenced DNA damage the most. The importance of sunlight was further emphasized by a positive association of the DNA damage level to the amount of time the subjects had spent in the sun over a 3 day period prior to the sampling. The effect...

Radiation damage of structural materials

International Nuclear Information System (INIS)

Koutsky, J.; Kocik, J.

1994-01-01

Maintaining the integrity of nuclear power plants (NPP) is critical in the prevention or control of severe accidents. This monograph deals with both basic groups of structural materials used in the design of light-water nuclear reactors, making the primary safety barriers of NPPs. Emphasis is placed on materials used in VVER-type nuclear reactors: Cr-Mo-V and Cr-Ni-Mo-V steel for reactor pressure vessels (RPV) and Zr-Nb alloys for fuel element cladding. The book is divided into seven main chapters, with the exception of the opening one and the chapter providing phenomenological background for the subject of radiation damage. Chapters 3-6 are devoted to RPV steels and chapters 7-9 to zirconium alloys, analyzing their radiation damage structure, changes of mechanical properties due to neutron irradiation as well as factors influencing the degree of their performance degradation. The recovery of damaged materials is also discussed. Considerable attention is paid to a comparison of VVER-type and western-type light-water materials

Hepatocyte growth factor gene-modified adipose-derived mesenchymal stem cells ameliorate radiation induced liver damage in a rat model.

Directory of Open Access Journals (Sweden)

Jiamin Zhang

Full Text Available Liver damage caused by radiotherapy is associated with a high mortality rate, but no established treatment exists. Adipose-derived mesenchymal stem cells (ADSCs are capable of migration to injured tissue sites, where they aid in the repair of the damage. Hepatocyte growth factor (HGF is critical for damage repair due to its anti-apoptotic, anti-fibrotic and cell regeneration-promoting effects. This study was performed to investigate the therapeutic effects of HGF-overexpressing ADSCs on radiation-induced liver damage (RILD. ADSCs were infected with a lentivirus encoding HGF and HGF-shRNA. Sprague-Dawley (SD rats received 60Gy of irradiation to induce liver injury and were immediately given either saline, ADSCs, ADSCs + HGF or ADSCs + shHGF. Two days after irradiation, a significant reduction in apoptosis was observed in the HGF-overexpressing ADSC group compared with the RILD group, as assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL staining. Scanning electron microscopy showed chromatin condensation after irradiation, which was ameliorated in the group that received ADSCs and was reversed in the group that received HGF-overexpressing ADSCs. HGF-overexpressing ADSCs ameliorated radiation- induced liver fibrosis through down regulation of α-SMA and fibronectin. Hepatocyte regeneration was significantly improved in rats treated with ADSCs compared with rats from the RILD group, as assessed by Ki-67 immunohistochemistry. Rats that received HGF-overexpressing ADSCs showed an even greater level of hepatocyte regeneration. HGF-overexpressing ADSCs completely blocked the radiation-induced increase in the enzymes ALT and AST. The effect of mitigating RILD was compromised in the ADSC + shHGF group compared with the ADSC group. Altogether, these results suggest that HGF-overexpressing ADSCs can significantly improve RILD in a rat model, which may serve as a valuable therapeutic alternative.

Intrauterine infection/inflammation during pregnancy and offspring brain damages: Possible mechanisms involved

Directory of Open Access Journals (Sweden)

Golan Hava

2004-04-01

Full Text Available Abstract Intrauterine infection is considered as one of the major maternal insults during pregnancy. Intrauterine infection during pregnancy could lead to brain damage of the developmental fetus and offspring. Effects on the fetal, newborn, and adult central nervous system (CNS may include signs of neurological problems, developmental abnormalities and delays, and intellectual deficits. However, the mechanisms or pathophysiology that leads to permanent brain damage during development are complex and not fully understood. This damage may affect morphogenic and behavioral phenotypes of the developed offspring, and that mice brain damage could be mediated through a final common pathway, which includes over-stimulation of excitatory amino acid receptor, over-production of vascularization/angiogenesis, pro-inflammatory cytokines, neurotrophic factors and apoptotic-inducing factors.

Damage analysis: damage function development and application

International Nuclear Information System (INIS)

Simons, R.L.; Odette, G.R.

1975-01-01

The derivation and application of damage functions, including recent developments for the U.S. LMFBR and CTR programs, is reviewed. A primary application of damage functions is in predicting component life expectancies; i.e., the fluence required in a service spectrum to attain a specified design property change. An important part of the analysis is the estimation of the uncertainty in such fluence limit predictions. The status of standardizing the procedures for the derivation and application of damage functions is discussed. Improvements in several areas of damage function development are needed before standardization can be completed. These include increasing the quantity and quality of the data used in the analysis, determining the limitations of the analysis due to the presence of multiple damage mechanisms, and finally, testing of damage function predictions against data obtained from material surveillance programs in operating thermal and fast reactors. 23 references. (auth)

Radiobiology in clinical radiation therapy - Part III: Normal tissue damage

International Nuclear Information System (INIS)

Travis, Elizabeth L.

1996-01-01

Objective: This is the third part of a course designed for residents in radiation oncology preparing for their boards. This part of the course will focus on the mechanisms underlying damage in normal tissues. Although conventional wisdom long held that killing and depletion of a critical cell(s) in a tissue was responsible for the later expression of damage, histopathologic changes in normal tissue can now be explained and better understood in terms of the new molecular biology. The concept that depletion of a single cell type is responsible for the observed histopathologic changes in normal tissues has been replaced by the hypothesis that damage results from the interaction of many different cell systems, including epithelial, endothelial, macrophages and fibroblasts, via the production of specific autocrine, paracrine and endocrine growth factors. A portion of this course will discuss the clinical and experimental data on the production and interaction of those cytokines and cell systems considered to be critical to tissue damage. It had long been suggested that interindividual differences in radiation-induced normal tissue damage was genetically regulated, at least in part. Both clinical and experimental data supported this hypothesis but it is the recent advances in human and mouse molecular genetics which have provided the tools to dissect out the genetic component of normal tissue damage. These data will be presented and related to the potential to develop genetic markers to identify sensitive individuals. The impact on clinical outcome of the ability to identify prospectively sensitive patients will be discussed. Clinically it is well-accepted that the volume of tissue irradiated is a critical factor in determining tissue damage. A profusion of mathematical models for estimating dose-volume relationships in a number of organs have been published recently despite the fact that little data are available to support these models. This course will review the

Lightning Strike Ablation Damage Influence Factors Analysis of Carbon Fiber/Epoxy Composite Based on Coupled Electrical-Thermal Simulation

Science.gov (United States)

Yin, J. J.; Chang, F.; Li, S. L.; Yao, X. L.; Sun, J. R.; Xiao, Y.

2017-10-01

According to the mathematical analysis model constructed on the basis of energy-balance relationship in lightning strike, and accompany with the simplified calculation strategy of composite resin pyrolysis degree dependent electrical conductivity, an effective three dimensional thermal-electrical coupling analysis finite element model of composite laminate suffered from lightning current was established based on ABAQUS, to elucidate the effects of lighting current waveform parameters and thermal/electrical properties of composite laminate on the extent of ablation damage. Simulated predictions agree well with the composite lightning strike directed effect experimental data, illustrating the potential accuracy of the constructed model. The analytical results revealed that extent of composite lightning strike ablation damage can be characterized by action integral validly, there exist remarkable power function relationships between action integral and visual damage area, projected damage area, maximum damage depth and damage volume of ablation damage, and enhancing the electrical conductivity and specific heat of composite, ablation damage will be descended obviously, power function relationships also exist between electrical conductivity, specific heat and ablation damage, however, the impact of thermal conductivity on the extent of ablation damage is not notable. The conclusions obtained provide some guidance for composite anti-lightning strike structure-function integration design.

Differential effects of experimental and cold-induced hyperthyroidism on factors inducing rat liver oxidative damage.

Science.gov (United States)

Venditti, P; Pamplona, R; Ayala, V; De Rosa, R; Caldarone, G; Di Meo, S

2006-03-01

Thyroid hormone-induced increase in metabolic rates is often associated with increased oxidative stress. The aim of the present study was to investigate the contribution of iodothyronines to liver oxidative stress in the functional hyperthyroidism elicited by cold, using as models cold-exposed and 3,5,3'-triiodothyronine (T3)- or thyroxine (T4)-treated rats. The hyperthyroid state was always associated with increases in both oxidative capacity and oxidative damage of the tissue. The most extensive damage to lipids and proteins was found in T3-treated and cold-exposed rats, respectively. Increase in oxygen reactive species released by mitochondria and microsomes was found to contribute to tissue oxidative damage, whereas the determination of single antioxidants did not provide information about the possible contribution of a reduced effectiveness of the antioxidant defence system. Indeed, liver oxidative damage in hyperthyroid rats was scarcely related to levels of the liposoluble antioxidants and activities of antioxidant enzymes. Conversely, other biochemical changes, such as the degree of fatty acid unsaturation and hemoprotein content, appeared to predispose hepatic tissue to oxidative damage associated with oxidative challenge elicited by hyperthyroid state. As a whole, our results confirm the idea that T3 plays a key role in metabolic changes and oxidative damage found in cold liver. However, only data concerning changes in glutathione peroxidase activity and mitochondrial protein content favour the idea that dissimilarities in effects of cold exposure and T3 treatment could depend on differences in serum levels of T4.

DNA damage response in monozygotic twins discordant for smoking habits.

Science.gov (United States)

Marcon, Francesca; Carotti, Daniela; Andreoli, Cristina; Siniscalchi, Ester; Leopardi, Paola; Caiola, Stefania; Biffoni, Mauro; Zijno, Andrea; Medda, Emanuela; Nisticò, Lorenza; Rossi, Sabrina; Crebelli, Riccardo

2013-03-01

Previous studies in twins indicate that non-shared environment, beyond genetic factors, contributes substantially to individual variation in mutagen sensitivity; however, the role of specific causative factors (e.g. tobacco smoke, diet) was not elucidated. In this investigation, a population of 22 couples of monozygotic twins with discordant smoking habits was selected with the aim of evaluating the influence of tobacco smoke on individual response to DNA damage. The study design virtually eliminated the contribution of genetic heterogeneity to the intra-pair variation in DNA damage response, and thus any difference in the end-points investigated could directly be attributed to the non-shared environment experienced by co-twins, which included as main factor cigarette smoke exposure. Peripheral lymphocytes of study subjects were challenged ex vivo with γ-rays, and the induction, processing, fixation of DNA damage evaluated through multiple approaches. Folate status of study subjects was considered significant covariate since it is affected by smoking habits and can influence radiosensitivity. Similar responses were elicited by γ-rays in co-twins for all the end-points analysed, despite their discordant smoking habits. Folate status did not modify DNA damage response, even though a combined effect of smoking habits, low-plasma folic acid level, and ionising radiation was observed on apoptosis. A possible modulation of DNA damage response by duration and intensity of tobacco smoke exposure was suggested by Comet assay and micronucleus data, but the effect was quantitatively limited. Overall, the results obtained indicate that differences in smoking habits do not contribute to a large extent to inter-individual variability in the response to radiation-induced DNA damage observed in healthy human populations.

Computer simulations of radiation damage in protein crystals

International Nuclear Information System (INIS)

Zehnder, M.

2007-03-01

The achievable resolution and the quality of the dataset of an intensity data collection for structure analysis of protein crystals with X-rays is limited among other factors by radiation damage. The aim of this work is to obtain a better quantitative understanding of the radiation damage process in proteins. Since radiation damage is unavoidable it was intended to look for the optimum ratio between elastically scattered intensity and radiation damage. Using a Monte Carlo algorithm physical processes after an inelastic photon interaction are studied. The main radiation damage consists of ionizations of the atoms through the electron cascade following any inelastic photon interaction. Results of the method introduced in this investigation and results of an earlier theoretical studies of the influence of Auger-electron transport in diamond are in a good agreement. The dependence of the radiation damage as a function of the energy of the incident photon was studied by computer-aided simulations. The optimum energy range for diffraction experiments on the protein myoglobin is 10-40 keV. Studies of radiation damage as a function of crystal volume and shape revealed that very small plate or rod shaped crystals suffer less damage than crystals formed like a cube with the same volume. Furthermore the influence of a few heavy atoms in the protein molecule on radiation damage was examined. Already two iron atoms in the unit cell of myoglobin increase radiation damage significantly. (orig.)

The role of Candida albicans homologous recombination factors Rad54 and Rdh54 in DNA damage sensitivity

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White Theodore C

2011-09-01

Full Text Available Abstract Background The fungal pathogen Candida albicans is frequently seen in immune suppressed patients, and resistance to one of the most widely used antifungals, fluconazole (FLC, can evolve rapidly. In recent years it has become clear that plasticity of the Candida albicans genome contributes to drug resistance through loss of heterozygosity (LOH at resistance genes and gross chromosomal rearrangements that amplify gene copy number of resistance associated genes. This study addresses the role of the homologous recombination factors Rad54 and Rdh54 in cell growth, DNA damage and FLC resistance in Candida albicans. Results The data presented here support a role for homologous recombination in cell growth and DNA damage sensitivity, as Candida albicans rad54Δ/rad54Δ mutants were hypersensitive to MMS and menadione, and had an aberrant cell and nuclear morphology. The Candida albicans rad54Δ/rad54Δ mutant was defective in invasion of Spider agar, presumably due to the altered cellular morphology. In contrast, mutation of the related gene RDH54 did not contribute significantly to DNA damage resistance and cell growth, and deletion of either Candida albicans RAD54 or Candida albicans RDH54 did not alter FLC susceptibility. Conclusions Together, these results support a role for homologous recombination in genome stability under nondamaging conditions. The nuclear morphology defects in the rad54Δ/rad54Δ mutants show that Rad54 performs an essential role during mitotic growth and that in its absence, cells arrest in G2. The viability of the single mutant rad54Δ/rad54Δ and the inability to construct the double mutant rad54Δ/rad54Δ rdh54Δ/rdh54Δ suggests that Rdh54 can partially compensate for Rad54 during mitotic growth.

Mitochondrial DNA damage and oxidative damage in HL-60 cells exposed to 900 MHz radiofrequency fields

Energy Technology Data Exchange (ETDEWEB)

Sun, Yulong; Zong, Lin; Gao, Zhen [School of Public Health, Soochow University, Suzhou, Jiangsu Province (China); Zhu, Shunxing [Laboratory Animal Center, Nantong University, Nantong, Jiangsu Province (China); Tong, Jian [School of Public Health, Soochow University, Suzhou, Jiangsu Province (China); Cao, Yi, E-mail: yicao@suda.edu.cn [School of Public Health, Soochow University, Suzhou, Jiangsu Province (China)

2017-03-15

Highlights: • Increased reactive oxygen species. • Decreased mitochondrial transcription Factor A and polymerase gamma. • Decreased mitochondrial transcripts (ND1 and 16S) and mtDNA copy number. • Increased 8-hydroxy-2′deoxyguanosine. • Decreased adenosine triphosphate. - Abstract: HL-60 cells, derived from human promyelocytic leukemia, were exposed to continuous wave 900 MHz radiofrequency fields (RF) at 120 μW/cm{sup 2} power intensity for 4 h/day for 5 consecutive days to examine whether such exposure is capable damaging the mitochondrial DNA (mtDNA) mediated through the production of reactive oxygen species (ROS). In addition, the effect of RF exposure was examined on 8-hydroxy-2′-dexoyguanosine (8-OHdG) which is a biomarker for oxidative damage and on the mitochondrial synthesis of adenosine triphosphate (ATP) which is the energy required for cellular functions. The results indicated a significant increase in ROS and significant decreases in mitochondrial transcription factor A, mtDNA polymerase gamma, mtDNA transcripts and mtDNA copy number in RF-exposed cells compared with those in sham-exposed control cells. In addition, there was a significant increase in 8-OHdG and a significant decrease in ATP in RF-exposed cells. The response in positive control cells exposed to gamma radiation (GR, which is also known to induce ROS) was similar to those in RF-exposed cells. Thus, the overall data indicated that RF exposure was capable of inducing mtDNA damage mediated through ROS pathway which also induced oxidative damage. Prior-treatment of RF- and GR-exposed the cells with melatonin, a well-known free radical scavenger, reversed the effects observed in RF-exposed cells.

Ice damage in loblolly pine: understanding the factors that influence susceptibility

Science.gov (United States)

Doug P. Aubrey; Mark D. Coleman; David R. Coyle

2007-01-01

Winter ice storms frequently occur in the southeastern United States and can severely damage softwood plantations. In January 2004, a severe storm deposited approximately 2 cm of ice on an intensively managed 4-year-old loblolly pine (Pinus taeda L.) plantation in South Carolina. Existing irrigation and fertilization treatments presented an...

Wood-damaging fungi in truss structures of baroque churches

Czech Academy of Sciences Publication Activity Database

Frankl, Jiří

2015-01-01

Roč. 29, č. 5 (2015), s. 04014138 ISSN 0887-3828 R&D Projects: GA ČR(CZ) GPP105/11/P628; GA MŠk(CZ) LO1219 Keywords : wood * biological damage * wood-damaging fungi Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 0.893, year: 2015 http://ascelibrary.org/doi/abs/10.1061/(ASCE)CF.1943-5509.0000632

ATM-Dependent Phosphorylation of MEF2D Promotes Neuronal Survival after DNA Damage

Science.gov (United States)

Chan, Shing Fai; Sances, Sam; Brill, Laurence M.; Okamoto, Shu-ichi; Zaidi, Rameez; McKercher, Scott R.; Akhtar, Mohd W.; Nakanishi, Nobuki

2014-01-01

Mutations in the ataxia telangiectasia mutated (ATM) gene, which encodes a kinase critical for the normal DNA damage response, cause the neurodegenerative disorder ataxia-telangiectasia (AT). The substrates of ATM in the brain are poorly understood. Here we demonstrate that ATM phosphorylates and activates the transcription factor myocyte enhancer factor 2D (MEF2D), which plays a critical role in promoting survival of cerebellar granule cells. ATM associates with MEF2D after DNA damage and phosphorylates the transcription factor at four ATM consensus sites. Knockdown of endogenous MEF2D with a short-hairpin RNA (shRNA) increases sensitivity to etoposide-induced DNA damage and neuronal cell death. Interestingly, substitution of endogenous MEF2D with an shRNA-resistant phosphomimetic MEF2D mutant protects cerebellar granule cells from cell death after DNA damage, whereas an shRNA-resistant nonphosphorylatable MEF2D mutant does not. In vivo, cerebella in Mef2d knock-out mice manifest increased susceptibility to DNA damage. Together, our results show that MEF2D is a substrate for phosphorylation by ATM, thus promoting survival in response to DNA damage. Moreover, dysregulation of the ATM–MEF2D pathway may contribute to neurodegeneration in AT. PMID:24672010

Hypoxia-ischemia and retinal ganglion cell damage

Directory of Open Access Journals (Sweden)

Charanjit Kaur

2008-08-01

Full Text Available Charanjit Kaur1, Wallace S Foulds2, Eng-Ang Ling11Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; 2Singapore Eye Research Institute, SingaporeAbstract: Retinal hypoxia is the potentially blinding mechanism underlying a number of sight-threatening disorders including central retinal artery occlusion, ischemic central retinal vein thrombosis, complications of diabetic eye disease and some types of glaucoma. Hypoxia is implicated in loss of retinal ganglion cells (RGCs occurring in such conditions. RGC death occurs by apoptosis or necrosis. Hypoxia-ischemia induces the expression of hypoxia inducible factor-1α and its target genes such as vascular endothelial growth factor (VEGF and nitric oxide synthase (NOS. Increased production of VEGF results in disruption of the blood retinal barrier leading to retinal edema. Enhanced expression of NOS results in increased production of nitric oxide which may be toxic to the cells resulting in their death. Excess glutamate release in hypoxic-ischemic conditions causes excitotoxic damage to the RGCs through activation of ionotropic and metabotropic glutamate receptors. Activation of glutamate receptors is thought to initiate damage in the retina by a cascade of biochemical effects such as neuronal NOS activation and increase in intracellular Ca2+ which has been described as a major contributing factor to RGC loss. Excess production of proinflammatory cytokines also mediates cell damage. Besides the above, free-radicals generated in hypoxic-ischemic conditions result in RGC loss because of an imbalance between antioxidant- and oxidant-generating systems. Although many advances have been made in understanding the mediators and mechanisms of injury, strategies to improve the damage are lacking. Measures to prevent neuronal injury have to be developed.Keywords: retinal hypoxia, retinal ganglion cells, glutamate receptors, neuronal injury, retina

The effects of vitamin E on brain derived neurotrophic factor, tissues oxidative damage and learning and memory of juvenile hypothyroid rats.

Science.gov (United States)

Baghcheghi, Yousef; Beheshti, Farimah; Shafei, Mohammad Naser; Salmani, Hossein; Sadeghnia, Hamid Reza; Soukhtanloo, Mohammad; Anaeigoudari, Akbar; Hosseini, Mahmoud

2018-06-01

The effects of vitamin E (Vit E) on brain derived neurotrophic factor (BDNF) and brain tissues oxidative damage as well as on learning and memory impairments in juvenile hypothyroid rats were examined. The rats were grouped as: (1) Control; (2) Propylthiouracil (PTU); (3) PTU-Vit E and (4) Vit E. PTU was added to their drinking water (0.05%) during 6 weeks. Vit E (20 mg/kg) was daily injected (IP). Morris water maze (MWM) and passive avoidance (PA) were carried out. The animals were deeply anesthetized and the brain tissues were removed for biochemical measurements. PTU increased the escape latency and traveled path in MWM (P E (P E improved BDNF, thiol, SOD and CAT while diminished MDA. The results of the present study showed that Vit E improved BDNF and prevented from brain tissues oxidative damage as well as learning and memory impairments in juvenile hypothyroid rats.

A pilot study of homocyst(e)ine levels in essential hypertension: relationship to von Willebrand factor, an index of endothelial damage.

Science.gov (United States)

Lip, G Y; Edmunds, E; Martin, S C; Jones, A F; Blann, A D; Beevers, D G

2001-07-01

An interaction between homocyst(e)ine and the endothelium in hypertensive patients may promote thrombogenesis and atherogenesis, leading to adverse cardiovascular events. We hypothesized that homocyst(e)ine levels are abnormal in patients with essential hypertension, and that this may be related to an adverse effect on the vascular endothelium. Accordingly, we compared plasma levels of homocyst(e)ine and von Willebrand factor (marking endothelial damage) in 83 patients (43 men; mean age 54 +/- standard deviation 15.9 years) with essential hypertension (> 160/90 mm Hg), with levels in 25 healthy normotensive controls (13 men; mean age 56+/-11.8 years). Baseline levels of the markers and other clinical indices were then related to adverse cardiovascular events at follow-up. Plasma homocyst(e)ine (P = .0001) and von Willebrand factor (P = .031) levels were significantly higher in hypertensives compared to controls. After a mean follow-up of 76 patients for 45 months (range, 1 to 66 months), 17 subjects experienced an end point of either cardiovascular death (n = 10) or adverse cardiovascular event (n = 7). Comparing these 17 with the 59 free of an end point, the former were older (P = .0002) and had a longer duration of known hypertension (P = .018). There was a nonsignificant trend toward higher median plasma homocyst(e)ine levels in the patients sustaining a vascular end point (P = .07). In this pilot study, we suggest that essential hypertension may be associated with increased plasma homocyst(e)ine levels, but that this amino acid is unrelated to endothelial damage (von Willebrand factor), clinical indices, or prognosis.

Damage Detection of Reinforced Concrete Shear Walls Using Mathematical Transformations

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Hosein Naderpour

2017-02-01

Full Text Available Structural health monitoring is a procedure to provide accurate and immediate information on the condition and efficiency of structures. There is variety of damage factors and the unpredictability of future damage, is a necessity for the use of structural health monitoring. Structural health monitoring and damage detection in early stages is one of the most interesting topics that had been paid attention because the majority of damages can be repaired and reformed by initial evaluation ,thus the spread of damage to the structures, building collapse and rising of costs can be avoided .Detection of concrete shear wall damages are designed to withstand the lateral load on the structure is critical .Because failures and  malfunctions of shear walls can lead to serious damage or even progressive dilapidation of concrete structures .Change in stiffness and frequency can clearly show the damage occurrence. Mathematical transformation is also a tool to detect damage. In this article, with non- linear time history analysis, the finite element model of structures with concrete shear walls subject to four earthquakes have extracted and using Fourier and wavelet transform, the presence of shear walls is detected at the time of damage.

Systems approach to the study of brain damage in the very preterm newborn

Science.gov (United States)

Leviton, Alan; Gressens, Pierre; Wolkenhauer, Olaf; Dammann, Olaf

2015-01-01

Background: A systems approach to the study of brain damage in very preterm newborns has been lacking. Methods: In this perspective piece, we offer encephalopathy of prematurity as an example of the complexity and interrelatedness of brain-damaging molecular processes that can be initiated inflammatory phenomena. Results: Using three transcription factors, nuclear factor-kappa B (NF-κB), Notch-1, and nuclear factor erythroid 2 related factor 2 (NRF2), we show the inter-connectedness of signaling pathways activated by some antecedents of encephalopathy of prematurity. Conclusions: We hope that as biomarkers of exposures and processes leading to brain damage in the most immature newborns become more readily available, those who apply a systems approach to the study of neuroscience can be persuaded to study the pathogenesis of brain disorders in the very preterm newborn. PMID:25926780

Neutron induced radiation damage

International Nuclear Information System (INIS)

Williams, M.M.R.

1977-01-01

We derive a general expression for the number of displaced atoms of type j caused by a primary knock-on of type i. The Kinchin-Pease model is used, but considerably generalised to allow for realistic atomic potentials. Two cases are considered in detail: the single particle problem causing a cascade and the neutron initiated problem which leads to multiple subcascades. Numerical results have been obtained for a variety of scattering laws. An important conclusion is that neutron initiated damage is much more severe than atom-initiated damage and leads to the number of displaced atoms being a factor of (A+1) 2 /4A larger than the single primary knock-on theory predicts. A is the ratio of the atomic mass to the neutron mass. The importance of this result to the theory of neutron sputtering is explained. (orig.) [de

Clinical research of teeth damage from radiotherapy

International Nuclear Information System (INIS)

Li Erzhou; Yan Maosheng; Chen Wei; Li Qing

2003-01-01

Objective: To analyze various factors inducing teeth damage from radiotherapy and the preventive and treatment methods. Methods: One hundred cases of patients treated by radiotherapy were divided into two groups. In group one there were 60 cases whose teeth were irradiated during treatment; in group two there were 40 cases whose teeth were not irradiated during treatment. Results: The caries incidence was 60% for group one and 15% for group two (P<0.01). By auto-control in 15 patients, the caries incidence on the sick side was obviously higher than that of the healthy side. Hundred percent caries incidence was found in 6 cases who received a dosage of 70 Gy. Conclusion: The authors believe that radiation damage to the teeth is associated with the following factors: 1. The dosage and location of irradiation are closely related to caries incidence; 2. The active dentinoblasts are very sensitive to radiation; 3. Damage to the salivary glands from radiotherapy can result in reduction of salvia and pH value, leading to a high growth rate of Streptococcus mutans. Following preventive measures could be considered in future cases: to apply a caries prevention coating or protective dental crown and TPS, to adjust the dose and time of irradiation, to select conformal radiotherapy technique. The key points for protecting the teeth and salivary gland from caries and damage are protection of the proliferation ability of pulp cells, anti-inflammation, promotion of microcirculation, and strengthening body resistance

Experimental study of oxidative DNA damage

DEFF Research Database (Denmark)

Loft, Steffen; Deng, Xin-Sheng; Tuo, Jingsheng

1998-01-01

Animal experiments allow the study of oxidative DNA damage in target organs and the elucidation of dose-response relationships of carcinogenic and other harmful chemicals and conditions as well as the study of interactions of several factors. So far the effects of more than 50 different chemical ...

High EDSS can predict risk for upper urinary tract damage in patients with multiple sclerosis.

Science.gov (United States)

Ineichen, Benjamin V; Schneider, Marc P; Hlavica, Martin; Hagenbuch, Niels; Linnebank, Michael; Kessler, Thomas M

2018-04-01

Neurogenic lower urinary tract dysfunction (NLUTD) is very common in patients with multiple sclerosis (MS), and it might jeopardize renal function and thereby increase mortality. Although there are well-known urodynamic risk factors for upper urinary tract damage, no clinical prediction parameters are available. We aimed to assess clinical parameters potentially predicting urodynamic risk factors for upper urinary tract damage. A consecutive series of 141 patients with MS referred from neurologists for primary neuro-urological work-up including urodynamics were prospectively evaluated. Clinical parameters taken into account were age, sex, duration, and clinical course of MS and Expanded Disability Status Scale (EDSS). Multivariate modeling revealed EDSS as a clinical parameter significantly associated with urodynamic risk factors for upper urinary tract damage (odds ratio = 1.34, 95% confidence interval (CI) = 1.06-1.71, p = 0.02). Using receiver operator characteristic (ROC) curves, an EDSS of 5.0 as cutoff showed a sensitivity of 86%-87% and a specificity of 52% for at least one urodynamic risk factor for upper urinary tract damage. High EDSS is significantly associated with urodynamic risk factors for upper urinary tract damage and allows a risk-dependent stratification in daily neurological clinical practice to identify MS patients requiring further neuro-urological assessment and treatment.

Damage detection in high-rise buildings using damage-induced rotations

International Nuclear Information System (INIS)

Sung, Seung Hun; Jung, Ho Youn; Lee, Jung Hoon; Jung, Hyung Jo

2016-01-01

In this paper, a new damage-detection method based on structural vibration is proposed. The essence of the proposed method is the detection of abrupt changes in rotation. Damage-induced rotation (DIR), which is determined from the modal flexibility of the structure, initially occurs only at a specific damaged location. Therefore, damage can be localized by evaluating abrupt changes in rotation. We conducted numerical simulations of two damage scenarios using a 10-story cantilever-type building model. Measurement noise was also considered in the simulation. We compared the sensitivity of the proposed method to localize damage to that of two conventional modal-flexibility-based damage-detection methods, i.e., uniform load surface (ULS) and ULS curvature. The proposed method was able to localize damage in both damage scenarios for cantilever structures, but the conventional methods could not

Damage detection in high-rise buildings using damage-induced rotations

International Nuclear Information System (INIS)

Sung, Seung Hoon; Jung, Ho Youn; Lee, Jung Hoon; Jung, Hyung Jo

2014-01-01

In this paper, a new damage-detection method based on structural vibration is proposed. The essence of the proposed method is the detection of abrupt changes in rotation. Damage-induced rotation (DIR), which is determined from the modal flexibility of the structure, initially occurs only at a specific damaged location. Therefore, damage can be localized by evaluating abrupt changes in rotation. We conducted numerical simulations of two damage scenarios using a 10-story cantilever-type building model. Measurement noise was also considered in the simulation. We compared the sensitivity of the proposed method to localize damage to that of two conventional modal-flexibility-based damage-detection methods, i.e., uniform load surface (ULS) and ULS curvature. The proposed method was able to localize damage in both damage scenarios for cantilever structures, but the conventional methods could not.

Cementing and formation damage; Cimentacao e dano a formacao

Energy Technology Data Exchange (ETDEWEB)

Souza, David Soares de [PETROBRAS, BA (Brazil). Distrito de Perfuracao da Bahia. Div. de Tecnicas e Operacoes

1994-07-01

This work presents a general perspective on cementing and formation damage. Few relative experiments to the damage to the formation, that they involve the casing activity and cementing, consider all the factors that affect these operations. So that she can analyze the contribution of a primary cementing has in the formation damage , it should be considered, also, the contribution of the drilling fluid and of the operation of the perforation. With base in experimental data of several accomplished studies, it can be concluded that a primary cementing has small, or any, contribution in the decrease of the productivity of an oil well.

Human activity and damaging landslides and floods on Madeira Island

Science.gov (United States)

Baioni, D.

2011-11-01

Over the last few decades, the island of Madeira has become an important offshore tourism and business center, with rapid economic and demographic development that has caused changes to the landscape due to human activity. In Madeira's recent history, there has been an increase over time in the frequency of occurrence of damaging landslide and flood events. As a result, the costs of restoration work due to damage caused by landslide and flood events have become a larger and larger component of Madeira's annual budget. Landslides and floods in Madeira deserve particular attention because they represent the most serious hazard to human life, to property, and to the natural environment and its important heritage value. The work reported on in this paper involved the analysis of historical data regarding damaging landslide and flood events on Madeira (in particular from 1941 to 1991) together with data on geological characteristics, topographic features, and climate, and from field observations. This analysis showed that the main factor triggering the occurrence of damaging landslide and flood events is rainfall, but that the increase in the number of damaging events recorded on Madeira Island, especially in recent times, seems to be related mostly to human activity, specifically to economic development and population growth, rather than to natural factors.

Measurement of damage in systemic vasculitis: a comparison of the Vasculitis Damage Index with the Combined Damage Assessment Index

DEFF Research Database (Denmark)

Suppiah, Ravi; Flossman, Oliver; Mukhtyar, Chetan

2011-01-01

To compare the Vasculitis Damage Index (VDI) with the Combined Damage Assessment Index (CDA) as measures of damage from vasculitis.......To compare the Vasculitis Damage Index (VDI) with the Combined Damage Assessment Index (CDA) as measures of damage from vasculitis....

Living with storm damage to forests

NARCIS (Netherlands)

Gardiner, B.; Schuck, A.; Schelhaas, M.J.; Orazio, C.; Blennow, K.; Nicoll, B.

2013-01-01

Windstorms are a major disturbance factor for European forests. In the past six decades wind storms have damaged standing forest volume, which on a yearly average equals about the size of Poland's annual fellings. The evedence also indicates that the actual severity of storms in the wake of climatic

Mitochondrial DNA Damage and Diseases [version 1; referees: 1 approved, 2 approved with reservations

Directory of Open Access Journals (Sweden)

Gyanesh Singh

2015-07-01

Full Text Available Various endogenous and environmental factors can cause mitochondrial DNA (mtDNA damage.  One of the reasons for enhanced mtDNA damage could be its proximity to the source of oxidants, and lack of histone-like protective proteins. Moreover, mitochondria contain inadequate DNA repair pathways, and, diminished DNA repair capacity may be one of the factors responsible for high mutation frequency of the mtDNA. mtDNA damage might cause impaired mitochondrial function, and, unrepaired mtDNA damage has been frequently linked with several diseases. Exploration of mitochondrial perspective of diseases might lead to a better understanding of several diseases, and will certainly open new avenues for detection, cure, and prevention of ailments.

Cavitation damage of ceramics

International Nuclear Information System (INIS)

Kovalenko, V.I.; Marinin, V.G.

1988-01-01

Consideration is given to results of investigation of ceramic material damage under the effect of cavitation field on their surface, formed in water under the face of exponential concentrator, connected with ultrasonic generator UZY-3-0.4. Amplitude of vibrations of concentrator face (30+-2)x10 -6 m, frequency-21 kHz. It was established that ceramics resistance to cavitation effect correlated with the product of critical of stress intensity factor and material hardness

Individual aircraft life monitoring: An engineering approach for fatigue damage evaluation

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Rui JIAO

2018-04-01

Full Text Available Individual aircraft life monitoring is required to ensure safety and economy of aircraft structure, and fatigue damage evaluation based on collected operational data of aircraft is an integral part of it. To improve the accuracy and facilitate the application, this paper proposes an engineering approach to evaluate fatigue damage and predict fatigue life for critical structures in fatigue monitoring. In this approach, traditional nominal stress method is applied to back calculate the S-N curve parameters of the realistic structure details based on full-scale fatigue test data. Then the S-N curve and Miner’s rule are adopted in damage estimation and fatigue life analysis for critical locations under individual load spectra. The relationship between relative small crack length and fatigue life can also be predicted with this approach. Specimens of 7B04-T74 aluminum alloy and TA15M titanium alloy are fatigue tested under two types of load spectra, and there is a good agreement between the experimental results and analysis results. Furthermore, the issue concerning scatter factor in individual aircraft damage estimation is also discussed. Keywords: Fatigue damage, Fatigue monitoring, Fatigue test, Scatter factor, S-N curve

Nondestructive damage detection and evaluation technique for seismically damaged structures

Science.gov (United States)

Adachi, Yukio; Unjoh, Shigeki; Kondoh, Masuo; Ohsumi, Michio

1999-02-01

The development of quantitative damage detection and evaluation technique, and damage detection technique for invisible damages of structures are required according to the lessons from the 1995 Hyogo-ken Nanbu earthquake. In this study, two quantitative damage sensing techniques for highway bridge structures are proposed. One method is to measure the change of vibration characteristics of the bridge structure. According to the damage detection test for damaged bridge column by shaking table test, this method can successfully detect the vibration characteristic change caused by damage progress due to increment excitations. The other method is to use self-diagnosis intelligent materials. According to the reinforced concrete beam specimen test, the second method can detect the damage by rupture of intelligent sensors, such as optical fiber or carbon fiber reinforced plastic rod.

Radiation damage in A-15 materials: EXAFS studies

International Nuclear Information System (INIS)

Knapp, G.S.; Kampwirth, R.T.; Georgopoulos, P.; Brown, B.S.

1980-01-01

EXAFS measurements are useful in determining the local atomic environment of a particular element in a solid. Since there has been some controversy about the nature of the defects produced in A-15 materials by radiation damage, such studies were carried out on some A-15 compounds, V 3 Ga which was damaged by neutrons, as well as Nb 3 Ge damaged by 2.5 MeV a particles. In the V 3 Ga sample, site exchange disorder seems to be the most important result of the neutron damage with less than 20% of the vanadium atoms on wrong sites. However, in the Nb 3 Ge samples in addition to site exchange disorder, an unusual splitting of the first near-neighbor distance between the Ge and Nb is found. This splitting, approximately 0.2 A, may explain the large Debye Waller factors observed by Burbank et al

Imaging the DNA damage response with PET and SPECT

Energy Technology Data Exchange (ETDEWEB)

Knight, James C.; Koustoulidou, Sofia; Cornelissen, Bart [University of Oxford, CR-UK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, Oxford (United Kingdom)

2017-06-15

DNA integrity is constantly challenged by endogenous and exogenous factors that can alter the DNA sequence, leading to mutagenesis, aberrant transcriptional activity, and cytotoxicity. Left unrepaired, damaged DNA can ultimately lead to the development of cancer. To overcome this threat, a series of complex mechanisms collectively known as the DNA damage response (DDR) are able to detect the various types of DNA damage that can occur and stimulate the appropriate repair process. Each DNA damage repair pathway leads to the recruitment, upregulation, or activation of specific proteins within the nucleus, which, in some cases, can represent attractive targets for molecular imaging. Given the well-established involvement of DDR during tumorigenesis and cancer therapy, the ability to monitor these repair processes non-invasively using nuclear imaging techniques may facilitate the earlier detection of cancer and may also assist in monitoring response to DNA damaging treatment. This review article aims to provide an overview of recent efforts to develop PET and SPECT radiotracers for imaging of DNA damage repair proteins. (orig.)

Self-Healing Characteristics of Damaged Rock Salt under Different Healing Conditions

Directory of Open Access Journals (Sweden)

Lin Li

2013-08-01

Full Text Available Salt deposits are commonly regarded as ideal hosts for geologic energy reservoirs. Underground cavern construction-induced damage in salt is reduced by self-healing. Thus, studying the influencing factors on such healing processes is important. This research uses ultrasonic technology to monitor the longitudinal wave velocity variations of stress-damaged rock salts during self-recovery experiments under different recovery conditions. The influences of stress-induced initial damage, temperature, humidity, and oil on the self-recovery of damaged rock salts are analyzed. The wave velocity values of the damaged rock salts increase rapidly during the first 200 h of recovery, and the values gradually increase toward stabilization after 600 h. The recovery of damaged rock salts is subjected to higher initial damage stress. Water is important in damage recovery. The increase in temperature improves damage recovery when water is abundant, but hinders recovery when water evaporates. The presence of residual hydraulic oil blocks the inter-granular role of water and restrains the recovery under triaxial compression. The results indicate that rock salt damage recovery is related to the damage degree, pore pressure, temperature, humidity, and presence of oil due to the sealing integrity of the jacket material.

Features of risks, damage claims processing and damage prevention overseas. Pt. 1

Energy Technology Data Exchange (ETDEWEB)

Splittgerber, E

1981-01-01

In opening up new raw material resources in remote locations and in the erection of industrial installations in overseas countries, manufacturers are often confronted with additional, unusual and hitherto unknown risks which can have considerable influence upon the orderly and timely execution of their projects. In Part I, various risk factors are considered from the experiences of Allianz as technical insurer in foreign damages connected with plant, civil and installation work insurance. The influence of climatic conditions upon damage events is illustrated with examples and the effects of storm, sand storm, flooding and earthquake discussed using a world map of natural dangers. The customs of people from culturally different nations and races, dictated as they often are by religion, must be taken into account by site managers and other staff on the building sites. The necessity for improvisations on building sites far from home and the limits of such improvisations are also discussed.

Cellular radiosensitivity and DNA damage in primary human fibroblasts

International Nuclear Information System (INIS)

Wurm, R.; Burnet, N.G.; Duggal, N.

1994-01-01

To evaluate the relationship between radiation-induced cell survival and DNA damage in primary human fibroblasts to decide whether the initial or residual DNA damage levels are more predictive of normal tissue cellular radiosensitivity. Five primary human nonsyndromic and two primary ataxia telangiectasia fibroblast strains grown in monolayer were studied. Cell survival was assessed by clonogenic assay. Irradiation was given at high dose rate (HDR) 1-2 Gy/min. DNA damage was measured in stationary phase cells and expressed as fraction released from the well by pulsed-field gel electrophoresis (PFGE). For initial damage, cells were embedded in agarose and irradiated at HDR on ice. Residual DNA damage was measured in monolayer by allowing a 4-h repair period after HDR irradiation. Following HDR irradiation, cell survival varied between SF 2 0.025 to 0.23. Measurement of initial DNA damage demonstrated linear induction up to 30 Gy, with small differences in the slope of the dose-response curve between strains. No correlation between cell survival and initial damage was found. Residual damage increased linearly up to 80 Gy with a variation in slope by a factor of 3.2. Cell survival correlated with the slope of the dose-response curves for residual damage of the different strains (p = 0.003). The relationship between radiation-induced cell survival and DNA damage in primary human fibroblasts of differing radiosensitivity is closest with the amount of DNA damage remaining after repair. If assays of DNA damage are to be used as predictors of normal tissue response to radiation, residual DNA damage provides the most likely correlation with cell survival. 52 refs., 5 figs., 2 tabs

SIRT participates at DNA damage response

Energy Technology Data Exchange (ETDEWEB)

Yun, Mi Yong; Joeng, Jae Min; Lee, Kee Ho [Korea Cancer Center Hospital, Seoul (Korea, Republic of); Park, Gil Hong [College of Medicine, Korea University, Seoul (Korea, Republic of)

2009-05-15

Sir2 maintains genomic stability in multiple ways in yeast. As a NAD{sup +}-dependent histone deacetylase, Sir2 has been reported to control chromatin silencing. In both budding yeast and Drosophila, overexpression of Sir2 extends life span. Previous reports have also demonstrated that Sir2 participate at DNA damage repair. A protein complex containing Sir2 has been reported to translocate to DNA double-strand breaks. Following DNA damage response, SIRT1 deacetylates p53 protein and attenuates its ability as a transcription factor. Consequently, SIRT1 over-expression increases cell survival under DNA damage inducing conditions. These previous observations mean a possibility that signals generated during the process of DNA repair are delivered through SIRT1 to acetylated p53. We present herein functional evidence for the involvement of SIRT1 in DNA repair response to radiation. In addition, this modulation of DNA repair activity may be connected to deacetylation of MRN proteins.

A registry analysis of damage to the deceased donor pancreas during procurement.

Science.gov (United States)

Ausania, F; Drage, M; Manas, D; Callaghan, C J

2015-11-01

Surgical injury to the pancreas is thought to occur commonly during procurement. The UK Transplant Registry was analyzed to determine the frequency of pancreatic injuries, identify factors associated with damage, and assess the impact of injuries on graft survival. Twelve hundred ninety-six pancreata were procured from donation after brain death donors, with 314 (19.5%) from donation after circulatory death donors. More than 50% of recovered pancreata had at least one injury, most commonly a short portal vein (21.5%). Liver donation, procurement team origin, hepatic artery (HA) arising from the superior mesenteric artery (SMA), and increasing donor BMI were associated with increased rates of pancreas damage on univariate analyses; on multivariate analysis only the presence of an HA from the SMA remained significant (p = 0.02). Six hundred forty solid organ pancreas transplants were performed; 238 had some form of damage. Overall, there was no difference in graft survival between damaged and undamaged organs (p = 0.28); however, graft loss was significantly more frequent in pancreata with arterial damage (p = 0.04) and in those with parenchymal damage (p = 0.05). Damage to the pancreas during organ recovery is more common than other organs, and meticulous surgical technique and awareness of damage risk factors are essential to reduce rates of procurement-related injuries. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

Radiation damage testing at the SSC [Superconducting Super Collider

International Nuclear Information System (INIS)

Chinowsky, W.; Thun, R.

1990-06-01

A Task Force on Radiation Damage Testing met at the SSC Laboratory on March 5--6, 1990. This Task Force was asked to assess the availability of appropriate facilities for radiation damage tests of SSC detector materials and components. The Task Force was also instructed to review the techniques and standards for conducting such tests. Semiconductors were considered separately from other detector materials. Radiation damage test of electronic devices generally require exposures to both ionizing radiation and neutrons, whereas non-electric components such as plastic scintillating materials, adhesives, cable insulation, and other organic polymers are adequately tested with ionizing radiation only. Test standards are discussed with respect to irradiation techniques, environmental factors, dosimetry, and mechanisms whereby various materials are damaged. It is emphasized that radiation sources should be chosen to duplicate as much as possible the expected SSC environment and that the effects from ionizing particles and from neutrons be investigated separately. Radiation damage tests at reactors must be designed with particular care complex spectra of neutrons and gamma rays are produced at such facilities. It is also essential to investigate dose-rate effects since they are known to be important in many cases. The required irradiations may last several months and are most easily carried out with dedicated radioactive sources. Environmental factors such as the presence of oxygen when testing plastic scintillators, or temperature when measuring semiconductor annealing effects, must also be taken into account. The importance of reliable dosimetry is stressed and suitable references cited. Finally, it is noted that an understanding of the mechanisms for radiation damage in semiconductor and other materials is important in planning irradiations and evaluating results

Experimental Study of Damage Evolution in Circular Stirrup-Confined Concrete.

Science.gov (United States)

Li, Zuohua; Peng, Zhihan; Teng, Jun; Wang, Ying

2016-04-08

This paper presents an experimental study on circular stirrup-confined concrete specimens under uniaxial and monotonic load. The effects of stirrup volume ratio, stirrup yield strength and concrete strength on damage evolution of stirrup-confined concrete were investigated. The experimental results showed that the strength and ductility of concrete are improved by appropriate arrangement of the stirrup confinement. Firstly, the concrete damage evolution can be relatively restrained with the increase of the stirrup volume ratio. Secondly, higher stirrup yield strength usually causes larger confining pressures and slower concrete damage evolution. In contrast, higher concrete strength leads to higher brittleness, which accelerates the concrete damage evolution. A plastic strain expression is obtained through curve fitting, and a damage evolution equation for circular stirrup-confined concrete is proposed by introducing a confinement factor ( C ) based on the experimental data. The comparison results demonstrate that the proposed damage evolution model can accurately describe the experimental results.

Experimental Study of Damage Evolution in Circular Stirrup-Confined Concrete

Science.gov (United States)

Li, Zuohua; Peng, Zhihan; Teng, Jun; Wang, Ying

2016-01-01

This paper presents an experimental study on circular stirrup-confined concrete specimens under uniaxial and monotonic load. The effects of stirrup volume ratio, stirrup yield strength and concrete strength on damage evolution of stirrup-confined concrete were investigated. The experimental results showed that the strength and ductility of concrete are improved by appropriate arrangement of the stirrup confinement. Firstly, the concrete damage evolution can be relatively restrained with the increase of the stirrup volume ratio. Secondly, higher stirrup yield strength usually causes larger confining pressures and slower concrete damage evolution. In contrast, higher concrete strength leads to higher brittleness, which accelerates the concrete damage evolution. A plastic strain expression is obtained through curve fitting, and a damage evolution equation for circular stirrup-confined concrete is proposed by introducing a confinement factor (C) based on the experimental data. The comparison results demonstrate that the proposed damage evolution model can accurately describe the experimental results. PMID:28773402

Laser-induced damage study of polymer PMMA

International Nuclear Information System (INIS)

Mansour, N.

2001-01-01

This article presents the results of bulk laser-induced damage measurements in polymer PMMA at 532 nm and 1064 nm for nanosecond laser pulses. The damage thresholds were measured for focused spot sizes ranging over two orders of magnitude. In this work, self-focusing effects were verified to be absent by measurements of breakdown thresholds using both linearly and circularly polarized light. At both 1064 nm and 532 nm, the dependence of the breakdown field, E B , on the spot size, ω, was empirically determined to be E B = C/√ω, where C depends on the wavelength. The extracted value for C(λ) at 1064 nm is larger by a factor of 5 than at 532 nm. Possible reasons for this strong dispersion and mechanism for laser-induced damage in polymer materials will be discussed

Ultraviolet-B lethal damage on Pseudomonas aeruginosa

International Nuclear Information System (INIS)

Degiorgi, C.F.; Fernandez, R.O.; Pizarro, R.A.

1996-01-01

Pseudomonas aeruginosa has shown an increased sensitivity compared with that of Escherichia coli and Enterobacter cloacae, when they were exposed to 0.4 kJ/m2 of ultraviolet-B radiation. The rapid decay in cell viability observed in Pseudomonas aeruginosa after the irradiation was influenced by factors such as culture media and the presence of pyocyanine during the irradiation. The radioinduced lethal damage could be prevented by photoreactivating treatment, indicating that pyrimidine dimer formation was the mechanism causing bacterial death. The results indicate that several environmental conditions may act as protective agents against ultraviolet-B-induced damage

Mitochondrial and Nuclear DNA Damage and Repair in Age-Related Macular Degeneration

Directory of Open Access Journals (Sweden)

Janusz Blasiak

2013-01-01

Full Text Available Aging and oxidative stress seem to be the most important factors in the pathogenesis of age-related macular degeneration (AMD, a condition affecting many elderly people in the developed world. However, aging is associated with the accumulation of oxidative damage in many biomolecules, including DNA. Furthermore, mitochondria may be especially important in this process because the reactive oxygen species produced in their electron transport chain can damage cellular components. Therefore, the cellular response to DNA damage, expressed mainly through DNA repair, may play an important role in AMD etiology. In several studies the increase in mitochondrial DNA (mtDNA damage and mutations, and the decrease in the efficacy of DNA repair have been correlated with the occurrence and the stage of AMD. It has also been shown that mitochondrial DNA accumulates more DNA lesions than nuclear DNA in AMD. However, the DNA damage response in mitochondria is executed by nucleus-encoded proteins, and thus mutagenesis in nuclear DNA (nDNA may affect the ability to respond to mutagenesis in its mitochondrial counterpart. We reported that lymphocytes from AMD patients displayed a higher amount of total endogenous basal and oxidative DNA damage, exhibited a higher sensitivity to hydrogen peroxide and UV radiation, and repaired the lesions induced by these factors less effectively than did cells from control individuals. We postulate that poor efficacy of DNA repair (i.e., is impaired above average for a particular age when combined with the enhanced sensitivity of retinal pigment epithelium cells to environmental stress factors, contributes to the pathogenesis of AMD. Collectively, these data suggest that the cellular response to both mitochondrial and nuclear DNA damage may play an important role in AMD pathogenesis.

Human activity and damaging landslides and floods on Madeira Island

Directory of Open Access Journals (Sweden)

D. Baioni

2011-11-01

Full Text Available Over the last few decades, the island of Madeira has become an important offshore tourism and business center, with rapid economic and demographic development that has caused changes to the landscape due to human activity. In Madeira's recent history, there has been an increase over time in the frequency of occurrence of damaging landslide and flood events. As a result, the costs of restoration work due to damage caused by landslide and flood events have become a larger and larger component of Madeira's annual budget. Landslides and floods in Madeira deserve particular attention because they represent the most serious hazard to human life, to property, and to the natural environment and its important heritage value.

The work reported on in this paper involved the analysis of historical data regarding damaging landslide and flood events on Madeira (in particular from 1941 to 1991 together with data on geological characteristics, topographic features, and climate, and from field observations. This analysis showed that the main factor triggering the occurrence of damaging landslide and flood events is rainfall, but that the increase in the number of damaging events recorded on Madeira Island, especially in recent times, seems to be related mostly to human activity, specifically to economic development and population growth, rather than to natural factors.

Using damage data to estimate the risk from summer convective precipitation extremes

Science.gov (United States)

Schroeer, Katharina; Tye, Mari

2017-04-01

This study explores the potential added value from including loss and damage data to understand the risks from high-intensity short-duration convective precipitation events. Projected increases in these events are expected even in regions that are likely to become more arid. Such high intensity precipitation events can trigger hazardous flash floods, debris flows, and landslides that put people and local assets at risk. However, the assessment of local scale precipitation extremes is hampered by its high spatial and temporal variability. In addition to this, not only are extreme events rare, but such small-scale events are likely to be underreported where they do not coincide with the observation network. Reports of private loss and damage on a local administrative unit scale (LAU 2 level) are used to explore the relationship between observed rainfall events and damages reportedly related to hydro-meteorological processes. With 480 Austrian municipalities located within our south-eastern Alpine study region, the damage data are available on a much smaller scale than the available rainfall data. Precipitation is recorded daily at 185 gauges and 52% of these stations additionally deliver sub-hourly rainfall information. To obtain physically plausible information, damage and rainfall data are grouped and analyzed on a catchment scale. The data indicate that rainfall intensities are higher on days that coincide with a damage claim than on days for which no damage was reported. However, approximately one third of the damages related to hydro-meteorological hazards were claimed on days for which no rainfall was recorded at any gauge in the respective catchment. Our goal is to assess whether these events indicate potential extreme events missing in the observations. Damage always is a consequence of an asset being exposed and susceptible to a hazardous process, and naturally, many factors influence whether an extreme rainfall event causes damage. We set up a statistical

Calculations on neutron irradiation damage in reactor materials

International Nuclear Information System (INIS)

Sone, Kazuho; Shiraishi, Kensuke

1976-01-01

Neutron irradiation damage calculations were made for Mo, Nb, V, Fe, Ni and Cr. Firstly, damage functions were calculated as a function of neutron energy with neutron cross sections of elastic and inelastic scatterings, and (n,2n) and (n,γ) reactions filed in ENDF/B-III. Secondly, displacement damage expressed in displacements per atom (DPA) was estimated for neutron environments such as fission spectrum, thermal neutron reactor (JMTR), fast breeder reactor (MONJU) and two fusion reactors (The Conceptual Design of Fusion Reactor in JAERI and ORNL-Benchmark). then, damage cross section in units of dpa. barn was defined as a factor to convert a given neutron fluence to the DPA value, and was calculated for the materials in the above neutron environments. Finally, production rates of helium and hydrogen atoms were calculated with (n,α) and (n,p) cross sections in ENDF/B-III for the materials irradiated in the above reactors. (auth.)

Genetic and environmental influences on oxidative damage assessed in elderly Danish twins

DEFF Research Database (Denmark)

Broedbaek, Kasper; Ribel-Madsen, Rasmus; Henriksen, Trine

2011-01-01

Previous studies have shown an association between oxidative stress and various diseases in humans including cancer, cardiovascular disease, diabetes, and chronic respiratory disease. To what extents this damage is determined by genetic and environmental factors is unknown. In a classical twin...... of oxidative stress were closely correlated (r=0.60-0.84). In conclusion, we demonstrated in a large population of elderly Danish twins that "whole-body" oxidative damage to nucleic acids and lipids is predominantly determined by potentially modifiable nongenetic factors....

On Monte Carlo estimation of radiation damage in light water reactor systems

International Nuclear Information System (INIS)

Read, Edward A.; Oliveira, Cassiano R.E. de

2010-01-01

There has been a growing need in recent years for the development of methodologies to calculate damage factors, namely displacements per atom (dpa), of structural components for Light Water Reactors (LWRs). The aim of this paper is discuss and highlight the main issues associated with the calculation of radiation damage factors utilizing the Monte Carlo method. Among these issues are: particle tracking and tallying in complex geometries, dpa calculation methodology, coupled fuel depletion and uncertainty propagation. The capabilities of the Monte Carlo code Serpent such as Woodcock tracking and burnup are assessed for radiation damage calculations and its capability demonstrated and compared to those of the MCNP code for dpa calculations of a typical LWR configuration involving the core vessel and the downcomer. (author)

INHIBITION OF FRIED MEAT-INDUCED DNA DAMAGE: A DIETARY INTERVENTION STUDY IN HUMANS

Science.gov (United States)

Dietary exposures have been implicated as risk factors in colorectal cancer. Such agents may act by causing DNA damage or may be protective against DNA damage. The effects of dietary exposures in causing or preventing damage have not been assessed directly in colon tissues. In th...

Silicon Damage Response Function Derivation and Verification: Assessment of Impact on ASTM Standard E722

Energy Technology Data Exchange (ETDEWEB)

Depriest, Kendall [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-06-01

Unsuccessful attempts by members of the radiation effects community to independently derive the Norgett-Robinson-Torrens (NRT) damage energy factors for silicon in ASTM standard E722-14 led to an investigation of the software coding and data that produced those damage energy factors. The ad hoc collaboration to discover the reason for lack of agreement revealed a coding error and resulted in a report documenting the methodology to produce the response function for the standard. The recommended changes in the NRT damage energy factors for silicon are shown to have significant impact for a narrow energy region of the 1-MeV(Si) equivalent fluence response function. However, when evaluating integral metrics over all neutrons energies in various spectra important to the SNL electronics testing community, the change in the response results in a small decrease in the total 1- MeV(Si) equivalent fluence of ~0.6% compared to the E722-14 response. Response functions based on the newly recommended NRT damage energy factors have been produced and are available for users of both the NuGET and MCNP codes.

Biological significance of the focus on DNA damage checkpoint factors remained after irradiation of ionizing radiation

International Nuclear Information System (INIS)

Yamauchi, Motohiro; Suzuki, Keiji

2005-01-01

This paper reviews recent reports on the focus formation and participation to checkpoint of (such phosphorylated (P-d) as below) ATM and H2AX, MDC1, 53BP1 and NBS1, and discusses their role in DNA damage checkpoint induction mainly around authors' studies. When the cell is irradiated by ionizing radiation, the subtype histone like H2AX is P-d and the formed focus', seen in the nucleus on immuno-fluorographic observation, represents the P-d H2AX at the damaged site of DNA. The role of P-d ATM (the product of causative gene of ataxia-telangiectasia mutation, a protein kinase) has been first shown by laser beam irradiation. Described are discussions on the roles and functions after irradiation in focus formation and DNA damage checkpoint of P-d H2AX (a specific histone product by the radiation like γ-ray as above), P-d ATM, MDC1 (a mediator of DNA damage check point protein 1), 53BP1, (a p53 binding protein) and NBS1 (the product of the causative gene of Nijmegen Breakage Syndrome). Authors have come to point out the remained focal size increase as implications of the efficient repair of damaged DNA, and the second cycled p53 accumulation, of tumor suppression. Thus evaluation of biological significance of these aspects, scarcely noted hitherto, is concluded important. (S.I.)

[Cranial nerve damage after neuroaxial methods of anesthesia in puerperas].

Science.gov (United States)

Floka, S E; Shifman, E M

2007-01-01

The paper describes cranial nerve damage, a rare complication of neuroaxial anesthesia in obstetric care. In the literature, there are summarized data on 17 cases of neurological deficit developing after subarachnoidal or epidural anesthesia in puerperas. The etiological and pathogenetic factors of the above complications may be suggested to be the high disposition of a local anesthetic, arterial hypotension due to neuroaxial anesthetics, the outflow of cerebrospinal fluid after pachymeningeal puncture (including after unintended puncture during epidural anesthesia), and ischemic injury after the blood packing performed to relieve postpuncture headache. Closer consideration of these risk factors seems to reduce the incidence of cranial nerve damage in puerperas.

Mechanisms of Retinal Damage after Ocular Alkali Burns.

Science.gov (United States)

Paschalis, Eleftherios I; Zhou, Chengxin; Lei, Fengyang; Scott, Nathan; Kapoulea, Vassiliki; Robert, Marie-Claude; Vavvas, Demetrios; Dana, Reza; Chodosh, James; Dohlman, Claes H

2017-06-01

Alkali burns to the eye constitute a leading cause of worldwide blindness. In recent case series, corneal transplantation revealed unexpected damage to the retina and optic nerve in chemically burned eyes. We investigated the physical, biochemical, and immunological components of retinal injury after alkali burn and explored a novel neuroprotective regimen suitable for prompt administration in emergency departments. Thus, in vivo pH, oxygen, and oxidation reduction measurements were performed in the anterior and posterior segment of mouse and rabbit eyes using implantable microsensors. Tissue inflammation was assessed by immunohistochemistry and flow cytometry. The experiments confirmed that the retinal damage is not mediated by direct effect of the alkali, which is effectively buffered by the anterior segment. Rather, pH, oxygen, and oxidation reduction changes were restricted to the cornea and the anterior chamber, where they caused profound uveal inflammation and release of proinflammatory cytokines. The latter rapidly diffuse to the posterior segment, triggering retinal damage. Tumor necrosis factor-α was identified as a key proinflammatory mediator of retinal ganglion cell death. Blockade, by either monoclonal antibody or tumor necrosis factor receptor gene knockout, reduced inflammation and retinal ganglion cell loss. Intraocular pressure elevation was not observed in experimental alkali burns. These findings illuminate the mechanism by which alkali burns cause retinal damage and may have importance in designing therapies for retinal protection. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

DAF-16/FOXO and EGL-27/GATA promote developmental growth in response to persistent somatic DNA damage.

Science.gov (United States)

Mueller, Michael M; Castells-Roca, Laia; Babu, Vipin; Ermolaeva, Maria A; Müller, Roman-Ulrich; Frommolt, Peter; Williams, Ashley B; Greiss, Sebastian; Schneider, Jennifer I; Benzing, Thomas; Schermer, Bernhard; Schumacher, Björn

2014-12-01

Genome maintenance defects cause complex disease phenotypes characterized by developmental failure, cancer susceptibility and premature ageing. It remains poorly understood how DNA damage responses function during organismal development and maintain tissue functionality when DNA damage accumulates with ageing. Here we show that the FOXO transcription factor DAF-16 is activated in response to DNA damage during development, whereas the DNA damage responsiveness of DAF-16 declines with ageing. We find that in contrast to its established role in mediating starvation arrest, DAF-16 alleviates DNA-damage-induced developmental arrest and even in the absence of DNA repair promotes developmental growth and enhances somatic tissue functionality. We demonstrate that the GATA transcription factor EGL-27 co-regulates DAF-16 target genes in response to DNA damage and together with DAF-16 promotes developmental growth. We propose that EGL-27/GATA activity specifies DAF-16-mediated DNA damage responses to enable developmental progression and to prolong tissue functioning when DNA damage persists.

Damage tolerant evaluation of cracked stiffened panels under ...

Indian Academy of Sciences (India)

Stiffened panels; stress intensity factor; fatigue and fracture; damage .... Extensive work on fracture analysis of structural components was carried out by using the ... respectively), in view of the transformation matrices related to MQL9S2 FE.

Life assessment of aerospace structure using damage tolerance

International Nuclear Information System (INIS)

Anwar, W.; Khan, M.Z.

2007-01-01

Damage Tolerant Design plays a major role in the Aerospace Industry not only in the design of new structures and components but also their ongoing maintenance and support. Damage Tolerance Analysis (DT A) is a procedure that defines whether a crack can be sustained safely during the projected service life of the structure. Using this methodology, service life of an aerospace structure can be determined and may be extended by applying proper tooling and machining for repair. In this research the effect of damage increment on the convergence of the residual strength is investigated for a wing component of an aircraft. The stresses redistribution with damage growth is discussed. Simulation using Linear Elastic Fracture Mechanics (LEFM) laws are performed, those results the damage scenarios to be assessed in the real structural geometry and loading environment, using Stress Intensity Factors, Critical Crack Sizes and the Residual Strength of that component. Fatigue crack growth behaviour of the component is also investigated experimentally. The fatigue experiments were performed under constant stress amplitude loadings and constant amplitude loading with single overload. It has been observed that the computed fatigue curves fit well with the experimental results. (author)

Modeling laser damage to the retina

Science.gov (United States)

Clark, Clifton D.

This dissertation presents recent progress in several areas related to modeling laser damage to the retina. In Chapter 3, we consider the consequences of using the Arrhenius damage model to predict the damage thresholds of multiple pulse, or repetitive pulse, exposures. We have identified a few fundamental trends associated with the multiple pulse damage predictions made by the Arrhenius model. These trends differ from what would be expected by non-thermal mechanisms, and could prove useful in differentiating thermal and non-thermal damage. Chapter 4 presents a new rate equation damage model hypothesized to describe photochemical damage. The model adds a temperature dependent term to the simple rate equation implied by the principle of reciprocity that is characteristic of photochemical damage thresholds. A recent damage threshold study, conducted in-vitro, has revealed a very sharp transition between thermal and photochemical damage threshold trends. For the wavelength used in the experiment (413 nm), thermal damage thresholds were observed at exposure levels that were twice the expected photochemical damage threshold, based on the traditional understanding of photochemical damage. Our model accounts for this observed trend by introducing a temperature dependent quenching, or repair, rate to the photochemical damage rate. For long exposures that give a very small temperature rise, the model reduces to the principle of reciprocity. Near the transition region between thermal and photochemical damage, the model allows the damage threshold to be set by thermal mechanisms, even at exposure above the reciprocity exposure. In Chapter 5, we describe a retina damage model that includes thermal lensing in the eye by coupling beam propagation and heat transfer models together. Thermal lensing has recently been suggested as a contributing factor to the large increase in measured retinal damage thresholds in the near infrared. The transmission of the vitreous decreases

Interface characteristics of peeling-off damages of laser coatings

Energy Technology Data Exchange (ETDEWEB)

Cui, Yun, E-mail: coating@siom.ac.cn; Yi, Kui; Guohang, Hu; Shao, Jianda

2014-01-30

Coating stacks of HfO{sub 2}/SiO{sub 2} and Ta{sub 2}O{sub 5}/SiO{sub 2} were separately prepared by electron beam evaporation and dual ion beam sputtering. Damage characteristics at the interlayer interfaces were analyzed after irradiation of the coatings by a 1064 nm laser. The cross-sectional morphologies of damage spots indicated that peeling-off damages always occurred at the interface where the low refractive index material (SiO{sub 2}) was deposited on the high refractive index material (HfO{sub 2} or Ta{sub 2}O{sub 5}). The effects of interface microstructure and components on peeling-off damages were also discussed. The microstructure of the interface was not a major factor that influenced peeling-off damages. Incomplete oxides (SiO{sub x}) and Na, K, Li ions accumulated near the interface and caused the formation of micro-defects layers with nano-sized thicknesses. Micro-defects layers maybe reduced adhesion of different interfaces and formed plasmas by absorbing laser energy. Finally stripping damages happened from micro-defects layers during irradiation by a 1064 nm laser.

Effects of hyperbaric oxygen and nerve growth factor on the long-term neural behavior of neonatal rats with hypoxic ischemic brain damage.

Science.gov (United States)

Wei, Lixia; Ren, Qing; Zhang, Yongjun; Wang, Jiwen

2017-04-01

To evaluate the effects of HBO (Hyperbaric oxygen) and NGF (Nerve growth factor) on the long-term neural behavior of neonatal rats with HIBD (Neonatal hypoxic ischemic brain damage). The HIBD model was produced by ligating the right common carotid artery of 7 days old SD (Sprague-Dawley) rats followed by 8% O2 + 92% N2 for 2h. Totally 40 rats were randomly divided into 5 groups including sham-operated group, HIBD control group, HBO treated group, NGF treated group and NGF + HBO treated group. The learning and memory ability of these rats was evaluated by Morris water maze at 30 days after birth, and sensory motor function was assessed by experiments of foot error and limb placement at 42 days after birth. The escape latency of HBO treated group, NGF treated group and NGF + HBO treated group was shorter than that of HIBD control group (pmemory ability and sensory motor function in neonatal rats after hypoxic ischemic brain damage.

Automated Damage Onset Analysis Techniques Applied to KDP Damage and the Zeus Small Area Damage Test Facility

International Nuclear Information System (INIS)

Sharp, R.; Runkel, M.

1999-01-01

Automated damage testing of KDP using LLNL's Zeus automated damage test system has allowed the statistics of KDP bulk damage to be investigated. Samples are now characterized by the cumulative damage probability curve, or S-curve, that is generated from hundreds of individual test sites per sample. A HeNe laser/PMT scatter diagnostic is used to determine the onset of damage at each test site. The nature of KDP bulk damage is such that each scatter signal may possess many different indicators of a damage event. Because of this, the determination of the initial onset for each scatter trace is not a straightforward affair and has required considerable manual analysis. The amount of testing required by crystal development for the National Ignition Facility (NIF) has made it impractical to continue analysis by hand. Because of this, we have developed and implemented algorithms for analyzing the scatter traces by computer. We discuss the signal cleaning algorithms and damage determination criteria that have lead to the successful implementation of a LabView based analysis code. For the typical R/1 damage data set, the program can find the correct damage onset in more than 80% of the cases, with the remaining 20% being left to operator determination. The potential time savings for data analysis is on the order of ∼ 100X over manual analysis and is expected to result in the savings of at least 400 man-hours over the next 3 years of NIF quality assurance testing

Meta-Analysis of Attitudes toward Damage-Causing Mammalian Wildlife

Science.gov (United States)

KANSKY, RUTH; KIDD, MARTIN; KNIGHT, ANDREW T

2014-01-01

Many populations of threatened mammals persist outside formally protected areas, and their survival depends on the willingness of communities to coexist with them. An understanding of the attitudes, and specifically the tolerance, of individuals and communities and the factors that determine these is therefore fundamental to designing strategies to alleviate human-wildlife conflict. We conducted a meta-analysis to identify factors that affected attitudes toward 4 groups of terrestrial mammals. Elephants (65%) elicited the most positive attitudes, followed by primates (55%), ungulates (53%), and carnivores (44%). Urban residents presented the most positive attitudes (80%), followed by commercial farmers (51%) and communal farmers (26%). A tolerance to damage index showed that human tolerance of ungulates and primates was proportional to the probability of experiencing damage while elephants elicited tolerance levels higher than anticipated and carnivores elicited tolerance levels lower than anticipated. Contrary to conventional wisdom, experiencing damage was not always the dominant factor determining attitudes. Communal farmers had a lower probability of being positive toward carnivores irrespective of probability of experiencing damage, while commercial farmers and urban residents were more likely to be positive toward carnivores irrespective of damage. Urban residents were more likely to be positive toward ungulates, elephants, and primates when probability of damage was low, but not when it was high. Commercial and communal farmers had a higher probability of being positive toward ungulates, primates, and elephants irrespective of probability of experiencing damage. Taxonomic bias may therefore be important. Identifying the distinct factors explaining these attitudes and the specific contexts in which they operate, inclusive of the species causing damage, will be essential for prioritizing conservation investments. Meta-Análisis de las Posturas hacia la Mam

Spatial distribution of radiation damage to crystalline proteins at 25–300 K

Energy Technology Data Exchange (ETDEWEB)

Warkentin, Matthew; Badeau, Ryan; Hopkins, Jesse B.; Thorne, Robert E., E-mail: ret6@cornell.edu [Cornell University, Ithaca, NY 14853 (United States)

2012-09-01

Dose-dependent atomic B factors are used to determine the average spatial distribution of radiation damage to crystalline thaumatin and urease. The spatial distribution of radiation damage (assayed by increases in atomic B factors) to thaumatin and urease crystals at temperatures ranging from 25 to 300 K is reported. The nature of the damage changes dramatically at approximately 180 K. Above this temperature the role of solvent diffusion is apparent in thaumatin crystals, as solvent-exposed turns and loops are especially sensitive. In urease, a flap covering the active site is the most sensitive part of the molecule and nearby loops show enhanced sensitivity. Below 180 K sensitivity is correlated with poor local packing, especially in thaumatin. At all temperatures, the component of the damage that is spatially uniform within the unit cell accounts for more than half of the total increase in the atomic B factors and correlates with changes in mosaicity. This component may arise from lattice-level, rather than local, disorder. The effects of primary structure on radiation sensitivity are small compared with those of tertiary structure, local packing, solvent accessibility and crystal contacts.

Chromatin modifications and the DNA damage response to ionizing radiation

International Nuclear Information System (INIS)

Kumar, Rakesh; Horikoshi, Nobuo; Singh, Mayank; Gupta, Arun; Misra, Hari S.; Albuquerque, Kevin; Hunt, Clayton R.; Pandita, Tej K.

2013-01-01

In order to survive, cells have evolved highly effective repair mechanisms to deal with the potentially lethal DNA damage produced by exposure to endogenous as well as exogenous agents. Ionizing radiation exposure induces highly lethal DNA damage, especially DNA double-strand breaks (DSBs), that is sensed by the cellular machinery and then subsequently repaired by either of two different DSB repair mechanisms: (1) non-homologous end joining, which re-ligates the broken ends of the DNA and (2) homologous recombination, that employs an undamaged identical DNA sequence as a template, to maintain the fidelity of DNA repair. Repair of DSBs must occur within the natural context of the cellular DNA which, along with specific proteins, is organized to form chromatin, the overall structure of which can impede DNA damage site access by repair proteins. The chromatin complex is a dynamic structure and is known to change as required for ongoing cellular processes such as gene transcription or DNA replication. Similarly, during the process of DNA damage sensing and repair, chromatin needs to undergo several changes in order to facilitate accessibility of the repair machinery. Cells utilize several factors to modify the chromatin in order to locally open up the structure to reveal the underlying DNA sequence but post-translational modification of the histone components is one of the primary mechanisms. In this review, we will summarize chromatin modifications by the respective chromatin modifying factors that occur during the DNA damage response.

Damage initiation and evolution in silicon nitride under\

Czech Academy of Sciences Publication Activity Database

Raga, R.; Khader, I.; Chlup, Zdeněk; Kailer, A.

360-361, AUG (2016), s. 147-159 ISSN 0043-1648 EU Projects: European Commission(XE) 263476 - ROLICER Institutional support: RVO:68081723 Keywords : Silicon nitride * Rollingcontactfatigue * Subsurface damage Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.531, year: 2016

Evaluation of Hail Simulated Damage on Marketable Tuber Yield of Potato Agria Cultivar in Ardabil Region

Directory of Open Access Journals (Sweden)

D. Hassanpanah

2012-07-01

Full Text Available This study was conducted at Ardabil Agriculture and Natural Resources Research Station during the year of 2010. A factorial experiment based on randomized complete block design with four replications and two factors were used to evaluate the effect of simulated hail damage to foliage at different growth stages of potato Agria cultivar on marketable tuber yield. The first factor consisted of six levels of foliar damage (0, 20, 40, 60, 80 and 100 percent and the second factor of five levels of plant growth stages (2, 5, 8, 11 and 15 weeks after the growing. Analysis of variance showed that there were significant differences among plants for levels and times of hail damage and their interactions in terms of marketable tuber yield. Percentage of marketable yield reduction at early stages of vegetative growth (2 weeks after growing was minimal. Occurrence of hail damage at the tuberization and bulking stages (5, 8 and 11 weeks after growing severely reduced marketable tuber yield. While, its damage at late growing stages of (14 weeks after growing on tuber yield was not appreciable. Times of hail damage on marketable tuber yield reduction was calculated through the regression. Relative reduction of marketable tuber yield at the early stages of vegetative growth, due to hail damage, against non-marketable tuber yield was higher than of bulking stage.

Stroke - risk factors

Science.gov (United States)

... oxygen. Brain cells can die, causing lasting damage. Risk factors are things that increase your chance of ... a disease or condition. This article discusses the risk factors for stroke and things you can do ...

Early recognition of damage and course of damage on metal components

International Nuclear Information System (INIS)

1992-01-01

In 1985, the German Research Association set up the programme 'Early recognition of damage and course of damage on metal components'. The concept worked out by a programme committee provided that scientifically secured bases for the understanding of the occurrence of damage, the prevention of damage, affecting damage, and the mechanism triggering damage, or cumulation of damage should be obtained. 36 individual projects costing 14 million DM were supported in the course of 6 years. The task of a test group was to find these projects from a far larger number of applications which promised an increase in knowledge in the sense of the target of the programme. For the final colloquium, the test group chose those contributions which had not previously been published to the wider technical public. (orig.) [de

Introducing tree interactions in wind damage simulations

NARCIS (Netherlands)

Schelhaas, M.J.; Kramer, K.; Peltola, H.; Werf, van der D.C.; Wijdeven, S.M.J.

2007-01-01

Wind throw is an important risk factor in forest management in North-western Europe. In recent years, mechanistic models have been developed to estimate critical wind speeds needed to break or uproot the average tree of a forest stand. Based on these models, we developed a wind damage module for the

Homocysteine and the C677T Gene Polymorphism of Its Key Metabolic Enzyme MTHFR Are Risk Factors of Early Renal Damage in Hypertension in a Chinese Han Population.

Science.gov (United States)

Yun, Lin; Xu, Rui; Li, Guohua; Yao, Yucai; Li, Jiamin; Cong, Dehong; Xu, Xingshun; Zhang, Lihua

2015-12-01

The combined hyperhomocysteinemia condition is a feature of the Chinese hypertensive population. This study used the case-control method to investigate the association between plasma homocysteine and the C677T gene polymorphism of its key metabolic enzyme, 5, 10-methylenetetrahydrofolate reductase (MTHFR), and early renal damage in a hypertensive Chinese Han population.A total of 379 adult essential hypertensive patients were selected as the study subjects. The personal information, clinical indicators, and the C677T gene polymorphism of MTHFR were texted. This study used the urine microalbumin/urine creatinine ratio (UACR) as a grouping basis: the hypertension without renal damage group (NRD group) and the hypertension combined with early renal damage group (ERD group).Early renal damage in the Chinese hypertensive population was associated with body weight, systolic pressure, diastolic pressure, urea nitrogen, serum creatinine, cystatin C, uric acid, aldosterone, and glomerular filtration rate. The homocysteine level and the UACR in the TT genotype group were higher than those in the CC genotype group. The binary logistic regression analysis results showed that after sex and age were adjusted, the MTHFR C677T gene polymorphism was correlated with early renal damage in hypertension in both the recessive model and in the additive model.Plasma homocysteine and the C677T gene polymorphism of its key metabolic enzyme MTHFR might be independent risk factors of early renal damage in the hypertensive Chinese Han population.

Laser annealing heals radiation damage in avalanche photodiodes

Energy Technology Data Exchange (ETDEWEB)

Lim, Jin Gyu [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); Anisimova, Elena; Higgins, Brendon L.; Bourgoin, Jean-Philippe [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Jennewein, Thomas [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Canadian Institute for Advanced Research, Quantum Information Science Program, Toronto, ON (Canada); Makarov, Vadim [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada)

2017-12-15

Avalanche photodiodes (APDs) are a practical option for space-based quantum communications requiring single-photon detection. However, radiation damage to APDs significantly increases their dark count rates and thus reduces their useful lifetimes in orbit. We show that high-power laser annealing of irradiated APDs of three different models (Excelitas C30902SH, Excelitas SLiK, and Laser Components SAP500S2) heals the radiation damage and several APDs are restored to typical pre-radiation dark count rates. Of nine samples we test, six APDs were thermally annealed in a previous experiment as another solution to mitigate the radiation damage. Laser annealing reduces the dark count rates further in all samples with the maximum dark count rate reduction factor varying between 5.3 and 758 when operating at -80 C. This indicates that laser annealing is a more effective method than thermal annealing. The illumination power to reach these reduction factors ranges from 0.8 to 1.6 W. Other photon detection characteristics, such as photon detection efficiency, timing jitter, and afterpulsing probability, fluctuate but the overall performance of quantum communications should be largely unaffected by these variations. These results herald a promising method to extend the lifetime of a quantum satellite equipped with APDs. (orig.)

Damage localization of marine risers using time series of vibration signals

Science.gov (United States)

Liu, Hao; Yang, Hezhen; Liu, Fushun

2014-10-01

Based on dynamic response signals a damage detection algorithm is developed for marine risers. Damage detection methods based on numerous modal properties have encountered issues in the researches in offshore oil community. For example, significant increase in structure mass due to marine plant/animal growth and changes in modal properties by equipment noise are not the result of damage for riser structures. In an attempt to eliminate the need to determine modal parameters, a data-based method is developed. The implementation of the method requires that vibration data are first standardized to remove the influence of different loading conditions and the autoregressive moving average (ARMA) model is used to fit vibration response signals. In addition, a damage feature factor is introduced based on the autoregressive (AR) parameters. After that, the Euclidean distance between ARMA models is subtracted as a damage indicator for damage detection and localization and a top tensioned riser simulation model with different damage scenarios is analyzed using the proposed method with dynamic acceleration responses of a marine riser as sensor data. Finally, the influence of measured noise is analyzed. According to the damage localization results, the proposed method provides accurate damage locations of risers and is robust to overcome noise effect.

Nuclear insulin-like growth factor 1 receptor phosphorylates proliferating cell nuclear antigen and rescues stalled replication forks after DNA damage.

Science.gov (United States)

Waraky, Ahmed; Lin, Yingbo; Warsito, Dudi; Haglund, Felix; Aleem, Eiman; Larsson, Olle

2017-11-03

We have previously shown that the insulin-like growth factor 1 receptor (IGF-1R) translocates to the cell nucleus, where it binds to enhancer-like regions and increases gene transcription. Further studies have demonstrated that nuclear IGF-1R (nIGF-1R) physically and functionally interacts with some nuclear proteins, i.e. the lymphoid enhancer-binding factor 1 (Lef1), histone H3, and Brahma-related gene-1 proteins. In this study, we identified the proliferating cell nuclear antigen (PCNA) as a nIGF-1R-binding partner. PCNA is a pivotal component of the replication fork machinery and a main regulator of the DNA damage tolerance (DDT) pathway. We found that IGF-1R interacts with and phosphorylates PCNA in human embryonic stem cells and other cell lines. In vitro MS analysis of PCNA co-incubated with the IGF-1R kinase indicated tyrosine residues 60, 133, and 250 in PCNA as IGF-1R targets, and PCNA phosphorylation was followed by mono- and polyubiquitination. Co-immunoprecipitation experiments suggested that these ubiquitination events may be mediated by DDT-dependent E2/E3 ligases ( e.g. RAD18 and SHPRH/HLTF). Absence of IGF-1R or mutation of Tyr-60, Tyr-133, or Tyr-250 in PCNA abrogated its ubiquitination. Unlike in cells expressing IGF-1R, externally induced DNA damage in IGF-1R-negative cells caused G 1 cell cycle arrest and S phase fork stalling. Taken together, our results suggest a role of IGF-1R in DDT. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

A multistep damage recognition mechanism for global genomic nucleotide excision repair.

Science.gov (United States)

Sugasawa, K; Okamoto, T; Shimizu, Y; Masutani, C; Iwai, S; Hanaoka, F

2001-03-01

A mammalian nucleotide excision repair (NER) factor, the XPC-HR23B complex, can specifically bind to certain DNA lesions and initiate the cell-free repair reaction. Here we describe a detailed analysis of its binding specificity using various DNA substrates, each containing a single defined lesion. A highly sensitive gel mobility shift assay revealed that XPC-HR23B specifically binds a small bubble structure with or without damaged bases, whereas dual incision takes place only when damage is present in the bubble. This is evidence that damage recognition for NER is accomplished through at least two steps; XPC-HR23B first binds to a site that has a DNA helix distortion, and then the presence of injured bases is verified prior to dual incision. Cyclobutane pyrimidine dimers (CPDs) were hardly recognized by XPC-HR23B, suggesting that additional factors may be required for CPD recognition. Although the presence of mismatched bases opposite a CPD potentiated XPC-HR23B binding, probably due to enhancement of the helix distortion, cell-free excision of such compound lesions was much more efficient than expected from the observed affinity for XPC-HR23B. This also suggests that additional factors and steps are required for the recognition of some types of lesions. A multistep mechanism of this sort may provide a molecular basis for ensuring the high level of damage discrimination that is required for global genomic NER.

Silencing of the transcription factor STAT3 sensitizes lung cancer cells to DNA damaging drugs, but not to TNFα- and NK cytotoxicity

Energy Technology Data Exchange (ETDEWEB)

Kulesza, Dorota W. [Laboratory of Transcription Regulation, Department of Cell Biology, The Nencki Institute of Experimental Biology, Warsaw (Poland); Postgraduate School of Molecular Medicine, Warsaw Medical University, Warsaw (Poland); Carré, Thibault; Chouaib, Salem [Unité INSERM U753, Institut de Cancérologie Gustave Roussy, Villejuif Cedex (France); Kaminska, Bozena, E-mail: bozenakk@nencki.gov.pl [Laboratory of Transcription Regulation, Department of Cell Biology, The Nencki Institute of Experimental Biology, Warsaw (Poland)

2013-02-15

Transcription factor STAT3 (Signal Transducers and Activators of Transcription 3) is persistently active in human tumors and may contribute to tumor progression. Inhibition of STAT3 expression/activity could be a good strategy to modulate tumor cell survival and responses to cancer chemotherapeutics or immune cytotoxicity. We silenced STAT3 expression in human A549 lung cancer cells to elucidate its role in cell survival and resistance to chemotherapeutics, TNFα and natural killer (NK)-mediated cytotoxicity. We demonstrate that STAT3 is not essential for basal survival and proliferation of A549 cancer cells. Stable silencing of STAT3 expression sensitized A549 cells to DNA damaging chemotherapeutics doxorubicin and cisplatin in a p53-independent manner. Sensitization to DNA damage-inducing chemotherapeutics could be due to down-regulation of the Bcl-xL expression in STAT3 depleted cells. In contrast, knockdown of STAT3 in cancer cells did not modulate responses to TNFα and NK-mediated cytotoxicity. We found that STAT3 depletion increased the NFκB activity likely providing the compensatory, pro-survival signal. The treatment with TNFα, but not doxorubicin, enhanced this effect. We conclude that STAT3 is not crucial for the control of basal cell proliferation and survival of lung carcinoma cells but modulates susceptibility to DNA damaging chemotherapeutics by regulation of intrinsic pro-survival pathways. - Highlights: ► STAT3 silencing is negligent for basal lung cancer cell viability and proliferation. ► STAT3 depletion sensitizes lung cancer cells to DNA damaging chemotherapeutics. ► STAT3 depletion has no effect on susceptibility to extrinsic apoptosis inducers. ► Increased pro-survival NFκB activity may compensate for STAT3 depletion.

Structure of a Novel DNA-binding Domain of Helicase-like Transcription Factor (HLTF) and Its Functional Implication in DNA Damage Tolerance.

Science.gov (United States)

Hishiki, Asami; Hara, Kodai; Ikegaya, Yuzu; Yokoyama, Hideshi; Shimizu, Toshiyuki; Sato, Mamoru; Hashimoto, Hiroshi

2015-05-22

HLTF (helicase-like transcription factor) is a yeast RAD5 homolog found in mammals. HLTF has E3 ubiquitin ligase and DNA helicase activities, and plays a pivotal role in the template-switching pathway of DNA damage tolerance. HLTF has an N-terminal domain that has been designated the HIRAN (HIP116 and RAD5 N-terminal) domain. The HIRAN domain has been hypothesized to play a role in DNA binding; however, the structural basis of, and functional evidence for, the HIRAN domain in DNA binding has remained unclear. Here we show for the first time the crystal structure of the HIRAN domain of human HLTF in complex with DNA. The HIRAN domain is composed of six β-strands and two α-helices, forming an OB-fold structure frequently found in ssDNA-binding proteins, including in replication factor A (RPA). Interestingly, this study reveals that the HIRAN domain interacts with not only with a single-stranded DNA but also with a duplex DNA. Furthermore, the structure unexpectedly clarifies that the HIRAN domain specifically recognizes the 3'-end of DNA. These results suggest that the HIRAN domain functions as a sensor to the 3'-end of the primer strand at the stalled replication fork and that the domain facilitates fork regression. HLTF is recruited to a damaged site through the HIRAN domain at the stalled replication fork. Furthermore, our results have implications for the mechanism of template switching. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

The study of past damaging hydrogeological events for damage susceptibility zonation

Directory of Open Access Journals (Sweden)

O. Petrucci

2008-08-01

Full Text Available Damaging Hydrogeological Events are defined as periods during which phenomena, such as landslides, floods and secondary floods, cause damage to people and the environment.

A Damaging Hydrogeological Event which heavily damaged Calabria (Southern Italy between December 1972, and January 1973, has been used to test a procedure to be utilised in the zonation of a province according to damage susceptibility during DHEs. In particular, we analyzed the province of Catanzaro (2391 km², an administrative district composed of 80 municipalities, with about 370 000 inhabitants.

Damage, defined in relation to the reimbursement requests sent to the Department of Public Works, has been quantified using a procedure based on a Local Damage Index. The latter, representing classified losses, has been obtained by multiplying the value of the damaged element and the percentage of damage affecting it.

Rainfall has been described by the Maximum Return Period of cumulative rainfall, for both short (1, 3, 5, 7, 10 consecutive days and long duration (30, 60, 90, 180 consecutive days, recorded during the event.

Damage index and population density, presumed to represent the location of vulnerable elements, have been referred to Thiessen polygons associated to rain gauges working at the time of the event.

The procedure allowed us to carry out a preliminary classification of the polygons composing the province according to their susceptibility to damage during DHEs. In high susceptibility polygons, severe damage occurs during rainfall characterised by low return periods; in medium susceptibility polygons maximum return period rainfall and induced damage show equal levels of exceptionality; in low susceptibility polygons, high return period rainfall induces a low level of damage.

The east and west sectors of the province show the highest susceptibility, while polygons of the N-NE sector show the lowest

Nucleolar exit of RNF8 and BRCA1 in response to DNA damage

International Nuclear Information System (INIS)

Guerra-Rebollo, Marta; Mateo, Francesca; Franke, Kristin; Huen, Michael S.Y.; Lopitz-Otsoa, Fernando; Rodríguez, Manuel S.; Plans, Vanessa; Thomson, Timothy M.

2012-01-01

The induction of DNA double-strand breaks (DSBs) elicits a plethora of responses that redirect many cellular functions to the vital task of repairing the injury, collectively known as the DNA damage response (DDR). We have found that, in the absence of DNA damage, the DSB repair factors RNF8 and BRCA1 are associated with the nucleolus. Shortly after exposure of cells to γ-radiation, RNF8 and BRCA1 translocated from the nucleolus to damage foci, a traffic that was reverted several hours after the damage. RNF8 interacted through its FHA domain with the ribosomal protein RPSA, and knockdown of RPSA caused a depletion of nucleolar RNF8 and BRCA1, suggesting that the interaction of RNF8 with RPSA is critical for the nucleolar localization of these DDR factors. Knockdown of RPSA or RNF8 impaired bulk protein translation, as did γ-irradiation, the latter being partially countered by overexpression of exogenous RNF8. Our results suggest that RNF8 and BRCA1 are anchored to the nucleolus through reversible interactions with RPSA and that, in addition to its known functions in DDR, RNF8 may play a role in protein synthesis, possibly linking the nucleolar exit of this factor to the attenuation of protein synthesis in response to DNA damage. -- Highlights: ► RNF8 and BRCA1 are associated with the nucleolus of undamaged cells. ► Upon γ-radiation, RNF8 and BRCA1 are translocated from the nucleolus to damage foci. ► The ribosomal protein RPSA anchors RNF8 to the nucleolus. ► RNF8 may play previously unsuspected roles in protein synthesis.

Damage scenarios and an onboard support system for damaged ships

Directory of Open Access Journals (Sweden)

Choi Jin

2014-06-01

Full Text Available Although a safety assessment of damaged ships, which considers environmental conditions such as waves and wind, is important in both the design and operation phases of ships, in Korea, rules or guidelines to conduct such assessments are not yet developed. However, NATO and European maritime societies have developed guidelines for a safety assessment. Therefore, it is required to develop rules or guidelines for safety assessments such as the Naval Ship Code (NSC of NATO. Before the safety assessment of a damaged ship can be performed, the available damage scenarios must be developed and the safety assessment criteria must be established. In this paper, the parameters related to damage by accidents are identified and categorized when developing damage scenarios. The need for damage safety assessment criteria is discussed, and an example is presented. In addition, a concept and specifications for the DB-based supporting system, which is used in the operation phases, are proposed.

Helicobacter pylori Infection Causes Characteristic DNA Damage Patterns in Human Cells

Directory of Open Access Journals (Sweden)

Max Koeppel

2015-06-01

Full Text Available Infection with the human pathogen Helicobacter pylori (H. pylori is a major risk factor for gastric cancer. Since the bacterium exerts multiple genotoxic effects, we examined the circumstances of DNA damage accumulation and identified regions within the host genome with high susceptibility to H. pylori-induced damage. Infection impaired several DNA repair factors, the extent of which depends on a functional cagPAI. This leads to accumulation of a unique DNA damage pattern, preferentially in transcribed regions and proximal to telomeres, in both gastric cell lines and primary gastric epithelial cells. The observed pattern correlates with focal amplifications in adenocarcinomas of the stomach and partly overlaps with known cancer genes. We thus demonstrate an impact of a bacterial infection directed toward specific host genomic regions and describe underlying characteristics that make such regions more likely to acquire heritable changes during infection, which could contribute to cellular transformation.

Gene and protein expression of epidermal growth factor measured on the kidney 24 hours after irradiation correlates to late radiation damage

International Nuclear Information System (INIS)

Otsuka, Makoto; Hatakenaka, Masamitsu

2001-01-01

This study was designed to evaluate the proliferative response of epidermal growth factor (EGF) gene expression as an early indicator of late renal radiation damage. EGF gene expression was measured in the irradiated left kidney of C3H/HeSlc mice using RT-PCR 24 hours after radiation doses of 9, 12, or 15 Gy. In a second experiment, the same radiation doses were administered to the right kidney plus the lower half of the left kidney. The partly irradiated left kidneys were harvested and EGF gene expression was measured. The irradiated whole right kidneys were subjected to immunohistochemical staining for EGF protein. In a third experiment, 12 Gy was administered to the right kidney plus the lower half of the left kidney. The mice underwent left nephrectomy 24 hours after radiation, and the EGF gene expression in the kidney was correlated with the blood urea nitrogen (BUN) level representing late renal functional damage. EGF expression increased in 1 of 10 control mice and in 9 of 10 mice that received 15 Gy. The extent of increase of EGF was dependent on radiation dose. In mice having an increased BUN level after irradiation, 7 of 10 had EGF positive irradiated kidneys. All six mice whose BUN levels were unchanged had EGF-negative irradiated kidneys. EGF protein staining was observed in tubule cells only, not in glomerular cells. The amount of EGF protein staining correlated with radiation dose to some extent. EGF gene expression seems to be a very early indicator of late radiation damage to the kidney. (author)

Estimate of the damage in organs induced by neutrons in three-dimensional conformal radiotherapy

International Nuclear Information System (INIS)

Benites R, J. L.; Vega C, H. R.; Uribe, M. del R.

2014-08-01

By means of Monte Carlo methods was considered the damage in the organs, induced by neutrons, of patients with cancer that receive treatment in modality of three-dimensional conformal radiotherapy (3D-CRT) with lineal accelerator Varian Ix. The objective of this work was to estimate the damage probability in radiotherapy patients, starting from the effective dose by neutrons in the organs and tissues out of the treatment region. For that a three-dimensional mannequin of equivalent tissue of 30 x 100 x 30 cm 3 was modeled and spherical cells were distributed to estimate the Kerma in equivalent tissue and the absorbed dose by neutrons. With the absorbed dose the effective dose was calculated using the weighting factors for the organ type and radiation type. With the effective dose and the damage factors, considered in the ICRP 103, was considered the probability of damage induction in organs. (Author)

Quantitative Analysis of Electron Beam Damage in Organic Thin Films

OpenAIRE

Leijten, Zino J. W. A.; Keizer, Arthur D. A.; de With, Gijsbertus; Friedrich, Heiner

2017-01-01

In transmission electron microscopy (TEM) the interaction of an electron beam with polymers such as P3HT:PCBM photovoltaic nanocomposites results in electron beam damage, which is the most important factor limiting acquisition of structural or chemical data at high spatial resolution. Beam effects can vary depending on parameters such as electron dose rate, temperature during imaging, and the presence of water and oxygen in the sample. Furthermore, beam damage will occur at different length s...

Paternal levels of DNA damage in spermatozoa and maternal parity influence offspring mortality in an endangered ungulate.

Science.gov (United States)

Ruiz-López, María José; Espeso, Gerardo; Evenson, Donald P; Roldan, Eduardo R S; Gomendio, Montserrat

2010-08-22

Understanding which factors influence offspring mortality rates is a major challenge since it influences population dynamics and may constrain the chances of recovery among endangered species. Most studies have focused on the effects of maternal and environmental factors, but little is known about paternal factors. Among most polygynous mammals, males only contribute the haploid genome to their offspring, but the possibility that sperm DNA integrity may influence offspring survival has not been explored. We examined several maternal, paternal and individual factors that may influence offspring survival in an endangered species (Gazella cuvieri). Levels of sperm DNA damage had the largest impact upon offspring mortality rates, followed by maternal parity. In addition, there was a significant interaction between these two variables, so that offspring born to primiparous mothers were more likely to die if their father had high levels of sperm DNA damage, but this was not the case among multiparous mothers. Thus, multiparous mothers seem to protect their offspring from the deleterious effects of sperm DNA damage. Since levels of sperm DNA damage seem to be higher among endangered species, more attention should be paid to the impact of this largely ignored factor among the viability of endangered species.

Biomarkers of oxidative damage to DNA and repair

DEFF Research Database (Denmark)

Loft, Steffen; Høgh Danielsen, Pernille; Mikkelsen, Lone

2008-01-01

environmental factors, including particulate air pollution, cause oxidative damage to DNA, whereas diets rich in fruit and vegetables or antioxidant supplements may reduce the levels and enhance repair. Urinary excretion of 8-oxodG, genotype and expression of OGG1 have been associated with risk of cancer...

Localization of simulated damage on a steel beam from random vibrations

Czech Academy of Sciences Publication Activity Database

Bayer, Jan; Král, J.; Urushadze, Shota

2018-01-01

Roč. 62, č. 1 (2018), s. 112-116 ISSN 0553-6626 R&D Projects: GA ČR(CZ) GC17-26353J Institutional support: RVO:68378297 Keywords : damage localization * change of natural modes * flexibility matrix * flexibility curvatures * case study * damage detection * vibration monitoring Subject RIV: JM - Building Engineering OBOR OECD: Construction engineering, Municipal and structural engineering Impact factor: 0.313, year: 2016 https://pp.bme.hu/ci/ article /view/10625

Implementation of an anisotropic damage material model using general second order damage tensor

NARCIS (Netherlands)

Niazi, Muhammad Sohail; Mori, K.; Wisselink, H.H.; Pietrzyk, M.; Kusiak, J.; Meinders, Vincent T.; ten Horn, Carel; Majta, J.; Hartley, P.; Lin, J.

2010-01-01

Damage in metals is mainly the process of the initiation and growth of voids. With the growing complexity in materials and forming proc-esses, it becomes inevitable to include anisotropy in damage (tensorial damage variable). Most of the anisotropic damage models define the damage tensor in the

Experimental Analysis and Discussion on the Damage Variable of Frozen Loess

Directory of Open Access Journals (Sweden)

Cong Cai

2017-01-01

Full Text Available The damage variable is very important to study damage evolution of material. Taking frozen loess as an example, a series of triaxial compression and triaxial loading-unloading tests are performed under five strain rates of 5.0 × 10−6–1.3 × 10−2/s at a temperature of −6°C. A damage criterion of frozen loess is defined and a damage factor Dc is introduced to satisfy the requirements of the engineering application. The damage variable of frozen loess is investigated using the following four methods: the stiffness degradation method, the deformation increase method, the dissipated energy increase method, and the constitutive model deducing method during deformation process. In addition, the advantages and disadvantages of the four methods are discussed when they are used for frozen loess material. According to the discussion, the plastic strain may be the most appropriate variable to characterize the damage evolution of frozen loess during the deformation process based on the material properties and the nature of the material service.

Thrombomodulin, von Willebrand factor and E-selectin as plasma markers of endothelial damage/dysfunction and activation in pregnancy induced hypertension.

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Nadar, Sunil K; Al Yemeni, Eman; Blann, Andrew D; Lip, Gregory Y H

2004-01-01

Endothelial disturbance (whether activation, dysfunction or damage) is a likely pathogenic mechanism in pre-eclampsia and pregnancy-induced hypertension (PIH). We set out to determine which of three plasma markers of endothelial disturbance, indicating endothelial activation (E-selectin) or damage/dysfunction (von Willebrand factor (vWf), soluble thrombomodulin), would provide the best discriminator of PIH compared to normotensive pregnancy. Cross-sectional study of 36 consecutive women with PIH (age 31+/-6 years) and 36 consecutive women with normotensive pregnancies (age 29+/-5 years) of similar parity. Plasma levels of vWf, E-selectin and thrombomodulin were measured using ELISA. As expected, women with PIH had significantly higher levels of plasma vWf (by 19%, p=0.003), E-selectin (by 40%, p<0.001) and thrombomodulin (by 61%, p=0.01) than normotensive women. However, on stepwise multiple regression analysis, only thrombomodulin was an independent significant predictor of the presence of PIH (p=0.023). We conclude that although vWf, E-selectin and thrombomodulin are all raised in PIH, only thrombomodulin was independently associated with PIH. This molecule could potentially be useful in monitoring and in providing clues in aetiology and pathophysiology, and may have implications for the clinical complications associated with PIH.

Injection technologies for the repair of damaged concrete structures

CERN Document Server

Panasyuk, V V; Sylovanyuk, V P

2014-01-01

This book analyzes the most important achievements in science and engineering practice concerning operational factors that cause damage to concrete and reinforced concrete structures. It includes methods for assessing their strength and service life, especially those that are based on modern concepts of the fracture mechanics of materials. It also includes basic approaches to the prediction of the remaining service life for long-term operational structures. Much attention is paid to injection technologies for restoring the serviceability of damaged concrete and reinforced concrete structures. In particular, technologies for remedying holes, cracks, corrosion damages etc. The books contains sample cases in which the above technologies have been used to restore structural integrity and extend the reliable service life of concrete and reinforced concrete constructions, especially NPPs, underground railways, bridges, seaports and historical relics.

DNA damage response during mouse oocyte maturation

Czech Academy of Sciences Publication Activity Database

Mayer, Alexandra; Baran, Vladimír; Sakakibara, Y.; Brzáková, Adéla; Ferencová, Ivana; Motlík, Jan; Kitajima, T.; Schultz, R. M.; Šolc, Petr

2016-01-01

Roč. 15, č. 4 (2016), s. 546-558 ISSN 1538-4101 R&D Projects: GA MŠk LH12057; GA MŠk ED2.1.00/03.0124 Institutional support: RVO:67985904 Keywords : double strand DNA breaks * DNA damage * MRE11 * meiotic maturation * mouse oocytes Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.530, year: 2016

Flood damage to historic buildings and structures

Czech Academy of Sciences Publication Activity Database

Drdácký, Miloš

2010-01-01

Roč. 24, č. 5 (2010), s. 439-445 ISSN 0887-3828 Grant - others:evropská komise(XE) FP6 Project cultural heritage protection against flood CHEF-SSPI-044251 Institutional research plan: CEZ:AV0Z20710524 Keywords : flood impact * historic structures * damage category Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 0.293, year: 2010

Lymphocyte DNA damage and oxidative stress in patients with iron deficiency anemia.

Science.gov (United States)

Aslan, Mehmet; Horoz, Mehmet; Kocyigit, Abdurrahim; Ozgonül, Saadet; Celik, Hakim; Celik, Metin; Erel, Ozcan

2006-10-10

Oxidant stress has been shown to play an important role in the pathogenesis of iron deficiency anemia. The aim of this study was to investigate the association between lymphocyte DNA damage, total antioxidant capacity and the degree of anemia in patients with iron deficiency anemia. Twenty-two female with iron deficiency anemia and 22 healthy females were enrolled in the study. Peripheral DNA damage was assessed using alkaline comet assay and plasma total antioxidant capacity was determined using an automated measurement method. Lymphocyte DNA damage of patients with iron deficiency anemia was significantly higher than controls (ptotal antioxidant capacity was significantly lower (ptotal antioxidant capacity and hemoglobin levels (r=0.706, ptotal antioxidant capacity and hemoglobin levels were negatively correlated with DNA damage (r=-0.330, p<0.05 and r=-0.323, p<0.05, respectively). In conclusion, both oxidative stress and DNA damage are increased in IDA patients. Increased oxidative stress seems as an important factor that inducing DNA damage in those IDA patients. The relationships of oxidative stress and DNA damage with the severity of anemia suggest that both oxidative stress and DNA damage may, in part, have a role in the pathogenesis of IDA.

Peroxidative damage of mitochondrial respiration is substrate-dependent

Czech Academy of Sciences Publication Activity Database

Endlicher, R.; Křiváková, P.; Rauchová, Hana; Nůsková, Hana; Červinková, Z.; Drahota, Zdeněk

2009-01-01

Roč. 58, č. 5 (2009), s. 685-692 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA303/06/1261 Institutional research plan: CEZ:AV0Z50110509 Keywords : mitochondrial enzymes * peroxidative damage * tert-butyl hydroperoxide Subject RIV: CE - Biochemistry Impact factor: 1.430, year: 2009

Nucleolar exit of RNF8 and BRCA1 in response to DNA damage

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Guerra-Rebollo, Marta; Mateo, Francesca; Franke, Kristin [Department of Cell Biology, Molecular Biology Institute of Barcelona (IBMB), CSIC, Barcelona Science Park, Helix Building, Baldiri Reixac 15-21, 08028 Barcelona (Spain); Huen, Michael S.Y. [Department of Anatomy, Centre for Cancer Research, The University of Hong Kong, L1, Laboratory Block, 21 Sassoon Road, Hong Kong Special Administrative Region (Hong Kong); Lopitz-Otsoa, Fernando; Rodriguez, Manuel S. [Proteomics Unit, CIC bioGUNE CIBERehd, ProteoRed, Technology Park of Bizkaia, Building 801A, 48160 Derio (Spain); Plans, Vanessa [Department of Cell Biology, Molecular Biology Institute of Barcelona (IBMB), CSIC, Barcelona Science Park, Helix Building, Baldiri Reixac 15-21, 08028 Barcelona (Spain); Thomson, Timothy M., E-mail: titbmc@ibmb.csic.es [Department of Cell Biology, Molecular Biology Institute of Barcelona (IBMB), CSIC, Barcelona Science Park, Helix Building, Baldiri Reixac 15-21, 08028 Barcelona (Spain)

2012-11-01

The induction of DNA double-strand breaks (DSBs) elicits a plethora of responses that redirect many cellular functions to the vital task of repairing the injury, collectively known as the DNA damage response (DDR). We have found that, in the absence of DNA damage, the DSB repair factors RNF8 and BRCA1 are associated with the nucleolus. Shortly after exposure of cells to {gamma}-radiation, RNF8 and BRCA1 translocated from the nucleolus to damage foci, a traffic that was reverted several hours after the damage. RNF8 interacted through its FHA domain with the ribosomal protein RPSA, and knockdown of RPSA caused a depletion of nucleolar RNF8 and BRCA1, suggesting that the interaction of RNF8 with RPSA is critical for the nucleolar localization of these DDR factors. Knockdown of RPSA or RNF8 impaired bulk protein translation, as did {gamma}-irradiation, the latter being partially countered by overexpression of exogenous RNF8. Our results suggest that RNF8 and BRCA1 are anchored to the nucleolus through reversible interactions with RPSA and that, in addition to its known functions in DDR, RNF8 may play a role in protein synthesis, possibly linking the nucleolar exit of this factor to the attenuation of protein synthesis in response to DNA damage. -- Highlights: Black-Right-Pointing-Pointer RNF8 and BRCA1 are associated with the nucleolus of undamaged cells. Black-Right-Pointing-Pointer Upon {gamma}-radiation, RNF8 and BRCA1 are translocated from the nucleolus to damage foci. Black-Right-Pointing-Pointer The ribosomal protein RPSA anchors RNF8 to the nucleolus. Black-Right-Pointing-Pointer RNF8 may play previously unsuspected roles in protein synthesis.

DNA damage assessment by visualization and quantification of DNA damage response

International Nuclear Information System (INIS)

Matsuda, Shun; Matsuda, Tomonari; Ikura, Tsuyoshi

2017-01-01

DNA damage response (DDR) carries out signal transduction for DNA repair, activation of cell cycle checkpoint, and apoptosis to maintain genome integrity, in response to DNA damage. Many proteins and their post-translational modifications participate in the process. Especially, S139-phosphorylated histone H2AX (γH2AX), which is formed by DNA double-strand breaks (DSBs), is an important factor to bring and retain other DDR proteins to DSB sites, Thus, γH2AX is used as a good indicator of DSBs in clinical study and pharmacology for efficacy evaluation of chemotherapy and radiotherapy, detection of precancerous regions, and others. In regulatory science, γH2AX is also a useful biomarker of genotoxicity of chemicals, since a wide range of genotoxic chemicals induce γH2AX. However, conventional detection methods of γH2AX absolutely require anti-γH2AX antibody whose staining is burdensome and time-consuming, and some of these methods are not so superior in quantitativity. In this review, we introduce two new methods to overcome these limitations, involving an easy-to-use genotoxicity assay using DDR-visualizing cells and an absolute quantification method of γH2AX using liquid chromatography-tandem mass spectrometry (LC/MS/MS). (author)

Immunochemical detection of oxidatively damaged DNA

Czech Academy of Sciences Publication Activity Database

Rössner ml., Pavel; Šrám, Radim

2012-01-01

Roč. 46, č. 4 (2012), s. 492-522 ISSN 1071-5762 R&D Projects: GA MŽP(CZ) SP/1B3/50/07; GA MŠk 2B08005; GA ČR GAP503/11/0084 Institutional research plan: CEZ:AV0Z50390703 Institutional support: RVO:68378041 Keywords : oxidative DNA damage * ELISA * immunohistochemistry Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 3.279, year: 2012

Anisotropic creep damage in the framework of continuum damage mechanics

International Nuclear Information System (INIS)

Caboche, J.L.

1983-01-01

For some years, various works have shown the possibility of applying continuum mechanics to model the evolution of the damage variable, initially introduced by Kachanov. Of interest here are the complex problems posed by the anisotropy which affects both the elastic behaviour and the viscoplastic one, and also the rupture phenomenon. The main concepts of the Continuum Damage Mechanics are briefly reviewed together with some classical ways to introduce anisotropy of damage in the particular case of proportional loadings. Based on previous works, two generalizations are presented and discussed, which use different kinds of tensors to describe the anisotropy of creep damage: - The first one, by Murakami and Ohno introduces a second rank damage tensor and a net stress tensor through a net area definition. The effective stress-strain behaviour is then obtained by a fourth rank tensor. - The second theory, by the author, uses one effective stress tensor only, defined in terms of the macroscopic strain behaviour, through a fourth-order non-symmetrical damage tensor. The two theories are compared at several levels: difference and similarities are pointed out for the damage evolution during tensile creep as well as for anisotropy effects. The possibilities are discussed and compared on the basis of some existing experimental results, which leads to a partial validation of the two approaches. (orig.)

Parvovirus infection-induced DNA damage response

Science.gov (United States)

Luo, Yong; Qiu, Jianming

2014-01-01

Parvoviruses are a group of small DNA viruses with ssDNA genomes flanked by two inverted terminal structures. Due to a limited genetic resource they require host cellular factors and sometimes a helper virus for efficient viral replication. Recent studies have shown that parvoviruses interact with the DNA damage machinery, which has a significant impact on the life cycle of the virus as well as the fate of infected cells. In addition, due to special DNA structures of the viral genomes, parvoviruses are useful tools for the study of the molecular mechanisms underlying viral infection-induced DNA damage response (DDR). This review aims to summarize recent advances in parvovirus-induced DDR, with a focus on the diverse DDR pathways triggered by different parvoviruses and the consequences of DDR on the viral life cycle as well as the fate of infected cells. PMID:25429305

DNA Damage and Pulmonary Hypertension

Science.gov (United States)

Ranchoux, Benoît; Meloche, Jolyane; Paulin, Roxane; Boucherat, Olivier; Provencher, Steeve; Bonnet, Sébastien

2016-01-01

Pulmonary hypertension (PH) is defined by a mean pulmonary arterial pressure over 25 mmHg at rest and is diagnosed by right heart catheterization. Among the different groups of PH, pulmonary arterial hypertension (PAH) is characterized by a progressive obstruction of distal pulmonary arteries, related to endothelial cell dysfunction and vascular cell proliferation, which leads to an increased pulmonary vascular resistance, right ventricular hypertrophy, and right heart failure. Although the primary trigger of PAH remains unknown, oxidative stress and inflammation have been shown to play a key role in the development and progression of vascular remodeling. These factors are known to increase DNA damage that might favor the emergence of the proliferative and apoptosis-resistant phenotype observed in PAH vascular cells. High levels of DNA damage were reported to occur in PAH lungs and remodeled arteries as well as in animal models of PH. Moreover, recent studies have demonstrated that impaired DNA-response mechanisms may lead to an increased mutagen sensitivity in PAH patients. Finally, PAH was linked with decreased breast cancer 1 protein (BRCA1) and DNA topoisomerase 2-binding protein 1 (TopBP1) expression, both involved in maintaining genome integrity. This review aims to provide an overview of recent evidence of DNA damage and DNA repair deficiency and their implication in PAH pathogenesis. PMID:27338373

Association between iron level, glucose impairment and increased DNA damage during pregnancy.

Science.gov (United States)

Zein, Salam; Rachidi, Samar; Shami, Nadine; Sharara, Iman; Cheikh-Ali, Khawla; Gauchez, Anne-Sophie; Moulis, Jean-Marc; Ayoubi, Jean-Marc; Salameh, Pascale; Hininger-Favier, Isabelle

2017-09-01

Elevated circulating ferritin has been reported to increase the risk of gestational diabetes mellitus (GDM). When high ferritin translates into high iron stores, iron excess is also a condition leading to free radical damage. We aimed to evaluate the relationship between oxidative stress (OS) induced by iron status and GDM risk in non iron-supplemented pregnant women. This was a pilot observational study conducted on 93 non-anemic pregnant women. Iron status was assessed at the first trimester of gestation. Blood sampling was done at 24-28 weeks' gestation for oral glucose tolerance test (OGTT), insulin and biological markers of oxidative damage tests. A significant increase in DNA damage was found in patients who developed GDM. Women with elevated DNA damage had a six-fold increased risk of developing GDM (Exp (B)=6.851, P=0.038; 95% CI [1.108-42.375]). The serum ferritin levels at first trimester were significantly correlated to lipid peroxidation (rho=0.24, p=0.012). The stratified analysis suggests that ferritin is a modifying factor for the correlation of oxidative stress (OS) and glucose intolerance. Moderate ferritin levels due to iron intake without iron-supplement, at early pregnancy is a modifying factor for the correlation of oxidative damage and glucose intolerance in pregnant women. Larger studies to evaluate the risk of food iron intake induced increased oxidative damage in offspring are warranted to propose nutrition advice regarding iron intake in women with a high risk of GDM. Copyright © 2016 Elsevier GmbH. All rights reserved.

Tornado risk analysis at Savannah River Plant using windspeed damage thresholds and single building strike frequencies

International Nuclear Information System (INIS)

Taylor, D.H.; McDonald, J.R.; Twisdale, L.A.

1985-01-01

Tornado risk analysis at the Savannah River Plant has taken a two pronged approach: (1) developing a catalogue of damage thresholds as a function of windspeed for processing buildings and other representative site structures; (2) developing a method of estimating, for each building, the probability of a tornado exceeding each damage threshold. Wind resistance of building construction at SRP varies widely depending on the function of the structure. It was recognized that all tornadoes do not necessarily seriously damage buildings, but the damage thresholds were unknown. In order to evaluate the safety of existing structures and properly design new structures, an analysis of tornado resistance was conducted by J.R. McDonald on each process building at SRP and other buildings by type. Damage estimates were catalogued for each Fujita class windspeed interval and windspeeds were catalogued as a function of increased levels of damage. Tornado single point and structure specific strike probabilities for the SRP site were determined by L.A. Twisdale using the TORRISK computer code. To calculate the structure specific strike probability, a correction factor is determined from a set of curves using building area and aspect ratio (length/width relative to north) as parameters. The structure specific probability is then the product of the correction factor and the point probability. The correction factor increases as a function of building size and windspeed. For large buildings (10 5 ft 2 ) and very intense storms (250 mph), the correction factor is equal to or greater than 4. The cumulative probability of a tornado striking any building type (process, personnel, etc.) was also calculated

Structural damage identification using damping: a compendium of uses and features

Science.gov (United States)

Cao, M. S.; Sha, G. G.; Gao, Y. F.; Ostachowicz, W.

2017-04-01

The vibration responses of structures under controlled or ambient excitation can be used to detect structural damage by correlating changes in structural dynamic properties extracted from responses with damage. Typical dynamic properties refer to modal parameters: natural frequencies, mode shapes, and damping. Among these parameters, natural frequencies and mode shapes have been investigated extensively for their use in damage characterization by associating damage with reduction in local stiffness of structures. In contrast, the use of damping as a dynamic property to represent structural damage has not been comprehensively elucidated, primarily due to the complexities of damping measurement and analysis. With advances in measurement technologies and analysis tools, the use of damping to identify damage is becoming a focus of increasing attention in the damage detection community. Recently, a number of studies have demonstrated that damping has greater sensitivity for characterizing damage than natural frequencies and mode shapes in various applications, but damping-based damage identification is still a research direction ‘in progress’ and is not yet well resolved. This situation calls for an overall survey of the state-of-the-art and the state-of-the-practice of using damping to detect structural damage. To this end, this study aims to provide a comprehensive survey of uses and features of applying damping in structural damage detection. First, we present various methods for damping estimation in different domains including the time domain, the frequency domain, and the time-frequency domain. Second, we investigate the features and applications of damping-based damage detection methods on the basis of two predominant infrastructure elements, reinforced concrete structures and fiber-reinforced composites. Third, we clarify the influential factors that can impair the capability of damping to characterize damage. Finally, we recommend future research directions

Sildenafil Attenuates Inflammation and Oxidative Stress in Pelvic Ganglia Neurons after Bilateral Cavernosal Nerve Damage

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Leah A. Garcia

2014-09-01

Full Text Available Erectile dysfunction is a common complication for patients undergoing surgeries for prostate, bladder, and colorectal cancers, due to damage of the nerves associated with the major pelvic ganglia (MPG. Functional re-innervation of target organs depends on the capacity of the neurons to survive and switch towards a regenerative phenotype. PDE5 inhibitors (PDE5i have been successfully used in promoting the recovery of erectile function after cavernosal nerve damage (BCNR by up-regulating the expression of neurotrophic factors in MPG. However, little is known about the effects of PDE5i on markers of neuronal damage and oxidative stress after BCNR. This study aimed to investigate the changes in gene and protein expression profiles of inflammatory, anti-inflammatory cytokines and oxidative stress related-pathways in MPG neurons after BCNR and subsequent treatment with sildenafil. Our results showed that BCNR in Fisher-344 rats promoted up-regulation of cytokines (interleukin- 1 (IL-1 β, IL-6, IL-10, transforming growth factor β 1 (TGFβ1, and oxidative stress factors (Nicotinamide adenine dinucleotide phosphate (NADPH oxidase, Myeloperoxidase (MPO, inducible nitric oxide synthase (iNOS, TNF receptor superfamily member 5 (CD40 that were normalized by sildenafil treatment given in the drinking water. In summary, PDE5i can attenuate the production of damaging factors and can up-regulate the expression of beneficial factors in the MPG that may ameliorate neuropathic pain, promote neuroprotection, and favor nerve regeneration.

The effect of dithiothreitol on radiation-induced genetic damage in Arabidopsis thaliana (L) Heynh

International Nuclear Information System (INIS)

Dellaert, L.M.W.

1980-01-01

A study was made on the effect of dithiothreitol (DTT; present during irradiation) on M 1 ovule sterility, M 2 embryonic lethals, M 2 chlorophyll mutants and M 2 viable mutants induced with fast neutrons or X-rays in Arabidopsis thaliana. DTT provides considerable protection against both fast-neutron and X-ray induced genetic damage. However, a higher protection was observed against M 1 ovule sterility, than against embryonic lethals, chlorophylls and viable mutants. This implies a significant DTT-induced spectral shift (0.01 < p < 0.05), i.e. a shift in the relative frequencies of the different genetic parameters. This spectral shift is explained on the basis of a specific DTT protection against radiation-induced strand breaks, and by differences in the ratio strand breaks/base damage for the genetic parameters concerned, i.e. a higher ratio for ovule sterility than for the other parameters. The induction of the genetic damage by ionizing radiation, either with or without DTT, is described by a mathematical model, which includes both strand breaks and base damage. The model shows that the resolving power of a test for a 'mutation'spectral shift depends on the relative values of the strandbreak reduction factor of -SH compounds and on the ratio strand breaks/base damage of the genetic parameters. For each genetic parameter the DTT damage reduction factor (DRF) is calculated per irradiation dose, and in addition the average (over-all doses) ratio strand breaks/base damage. (orig.)

Hemostasis and endothelial damage during sepsis.

Science.gov (United States)

Johansen, Maria Egede

2015-08-01

The sepsis syndrome represents a disease continuum, including severe sepsis and septic shock associated with high mortality. One of the main problems in severe sepsis and septic shock, resulting in organ failure and death, are disturbances in the hemostasis due to sepsis-related coagulopathy. Sepsis-related coagulopathy affects not only traditional coagulation factors, but also the platelets and endothelium. Functional testing of the hemostatic system has found application in critical illness. Thrombelastography (TEG) provides an overview of the hemostatic system allowing for an evaluation of interactions between coagulation factors and platelets. Additionally, the role of the endothelium during sepsis can be explored through testing of biomarkers of endothelial damage. The three studies comprising this PhD thesis all investigate important aspects of the disturbed hemostasis during sepsis, including endothelial damage. Together, the specific findings from the three studies improve the existing understanding of sepsis-related coagulopathy, and the possible influences of some of the treatments offered these patients. The first study investigates the occurrence of antimicrobial-induced thrombocytopenia among critically ill patients. In sepsis, thrombocytopenia is a predictor of poor outcome, and reports, of mainly casuistic nature, have previously hypothesized that specific antimicrobial agents could induce in sepsis-related thrombocytopenia. This hypothesis was tested using a randomized designed set-up, encompassing 1147 critically ill patients, and no significant difference in risk of thrombocytopenia was observed among patients receiving large amounts of antimicrobials vs. patients receiving standard-of-care. As a consequence, the risk of antimicrobial-induced thrombocytopenia in the general population of critically ill patients seemingly does not represent a substantial problem and thrombocytopenia during critical illness is most likely due to other factors such

Ultraviolet damage to the eye revisited: eye-sun protection factor (E-SPF®), a new ultraviolet protection label for eyewear

Science.gov (United States)

Behar-Cohen, Francine; Baillet, Gilles; de Ayguavives, Tito; Garcia, Paula Ortega; Krutmann, Jean; Peña-García, Pablo; Reme, Charlotte; Wolffsohn, James S

2014-01-01

Ultraviolet (UV) radiation potentially damages the skin, the immune system, and structures of the eye. A useful UV sun protection for the skin has been established. Since a remarkable body of evidence shows an association between UV radiation and damage to structures of the eye, eye protection is important, but a reliable and practical tool to assess and compare the UV-protective properties of lenses has been lacking. Among the general lay public, misconceptions on eye-sun protection have been identified. For example, sun protection is mainly ascribed to sunglasses, but less so to clear lenses. Skin malignancies in the periorbital region are frequent, but usual topical skin protection does not include the lids. Recent research utilized exact dosimetry and demonstrated relevant differences in UV burden to the eye and skin at a given ambient irradiation. Chronic UV effects on the cornea and lens are cumulative, so effective UV protection of the eyes is important for all age groups and should be used systematically. Protection of children’s eyes is especially important, because UV transmittance is higher at a very young age, allowing higher levels of UV radiation to reach the crystalline lens and even the retina. Sunglasses as well as clear lenses (plano and prescription) effectively reduce transmittance of UV radiation. However, an important share of the UV burden to the eye is explained by back reflection of radiation from lenses to the eye. UV radiation incident from an angle of 135°–150° behind a lens wearer is reflected from the back side of lenses. The usual antireflective coatings considerably increase reflection of UV radiation. To provide reliable labeling of the protective potential of lenses, an eye-sun protection factor (E-SPF®) has been developed. It integrates UV transmission as well as UV reflectance of lenses. The E-SPF® compares well with established skin-sun protection factors and provides clear messages to eye health care providers and to

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) enhances vascular and renal damage induced by hyperlipidemic diet in ApoE-knockout mice.

Science.gov (United States)

Muñoz-García, Begoña; Moreno, Juan Antonio; López-Franco, Oscar; Sanz, Ana Belén; Martín-Ventura, José Luis; Blanco, Julia; Jakubowski, Aniela; Burkly, Linda C; Ortiz, Alberto; Egido, Jesús; Blanco-Colio, Luis Miguel

2009-12-01

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is a member of the tumor necrosis factor superfamily of cytokines. TWEAK binds and activates the Fn14 receptor, and may regulate apoptosis, inflammation, and angiogenesis, in different pathological conditions. We have evaluated the effect of exogenous TWEAK administration as well as the role of endogenous TWEAK on proinflammatory cytokine expression and vascular and renal injury severity in hyperlipidemic ApoE-knockout mice. ApoE(-/-) mice were fed with hyperlipidemic diet for 4 to 10 weeks, then randomized and treated with saline (controls), TWEAK (10 microg/kg/d), anti-TWEAK neutralizing mAb (1000 microg/kg/d), TWEAK plus anti-TWEAK antibody (10 microg TWEAK +1000 microg anti-TWEAK/kg/d), or nonspecific IgG (1000 microg/kg/d) daily for 9 days. In ApoE(-/-) mice, exogenous TWEAK administration in ApoE(-/-) mice induced activation of NF-kappaB, a key transcription factor implicated in the regulation of the inflammatory response, in vascular and renal lesions. Furthermore, TWEAK treatment increased chemokine expression (RANTES and MCP-1), as well as macrophage infiltration in atherosclerotic plaques and renal lesions. These effects were associated with exacerbation of vascular and renal damage. Conversely, treatment of ApoE(-/-) mice with an anti-TWEAK blocking mAb decreased NF-kappaB activation, proinflammatory cytokine expression, macrophage infiltration, and vascular and renal injury severity, indicating a pathological role for endogenous TWEAK. Finally, in murine vascular smooth muscle cells or tubular cells, either ox-LDL or TWEAK treatment increased expression and secretion of both RANTES and MCP-1. Furthermore, ox-LDL and TWEAK synergized for induction of MCP-1 and RANTES expression and secretion. Our results suggest that TWEAK exacerbates the inflammatory response associated with a high lipid-rich diet. TWEAK may be a novel therapeutic target to prevent vascular and renal damage associated with

Radiotherapy- and chemotherapy-induced normal tissue damage. The role of cytokines and adhesion molecules

International Nuclear Information System (INIS)

Plevova, P.

2002-01-01

Background. Ionising radiation and cytostatic agents used in cancer therapy exert damaging effects on normal tissues and induce a complex response at the cellular and molecular levels. Cytokines and adhesion molecules are involved in this response. Methods. Published data on the given topic have been reviewed. Results and conclusions. Various cytokines and adhesion molecules, including tumor necrosis factor α, interleukins- 1,-2,-4, and -6, interferon γ, granulocyte macrophage- and macrophage- colony stimulating factors, transforming growth factor β, platelet-derived growth factor, insulin-like growth factor I, fibroblast and epidermal growth factors, platelet-activating factor, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E- and P-selectins are involved in the response of normal tissues to ionizing radiation- and chemotherapy- induced normal tissues damage and are co-responsible for some side effects of these treatment modalities, including fever, anorexia and fatigue, suppression of hematopoiesis, both acute and late local tissue response. (author)

A simplified baseline prediction model for joint damage progression in rheumatoid arthritis: a step toward personalized medicine.

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de Punder, Yvonne M R; van Riel, Piet L C M; Fransen, Jaap

2015-03-01

To compare the performance of an extended model and a simplified prognostic model for joint damage in rheumatoid arthritis (RA) based on 3 baseline risk factors: anticyclic citrullinated peptide antibodies (anti-CCP), erosions, and acute-phase reaction. Data were used from the Nijmegen early RA cohort. An extended model and a simplified baseline prediction model were developed to predict joint damage progression between 0 and 3 years. Joint damage progression was assessed using the Ratingen score. In the extended model, prediction factors were positivity for anti-CCP and/or rheumatoid factor, the level of erythrocyte sedimentation rate, and the quantity of erosions. The prediction score was calculated as the sum of the regression coefficients. In the simplified model, the prediction factors were dichotomized and the number of risk factors was counted. Performances of both models were compared using discrimination and calibration. The models were internally validated using bootstrapping. The extended model resulted in a prediction score between 0 and 5.6 with an area under the receiver-operation characteristic (ROC) curve of 0.77 (95% CI 0.72-0.81). The simplified model resulted in a prediction score between 0 and 3. This model had an area under the ROC curve of 0.75 (95% CI 0.70-0.80). In internal validation, the 2 models showed reasonably well the agreement between observed and predicted probabilities for joint damage progression (Hosmer-Lemeshow test p > 0.05 and calibration slope near 1.0). A simple prediction model for joint damage progression in early RA, by only counting the number of risk factors, has adequate performance. This facilitates the translation of the theoretical prognostic models to daily clinical practice.

DNA damage and plasma homocysteine levels are associated with ...

African Journals Online (AJOL)

This study describes the association between levels of DNA damage and homocysteine (Hcy) in persistent diarrheic (PD) patients and correlates them with serum biochemical metabolites and mineral components. PD patients (n = 36) age 4 - 6 years from Faisalabad hospitals were examined for anthropometric factors, ...

Development of damage probability matrices based on Greek earthquake damage data

Science.gov (United States)

Eleftheriadou, Anastasia K.; Karabinis, Athanasios I.

2011-03-01

A comprehensive study is presented for empirical seismic vulnerability assessment of typical structural types, representative of the building stock of Southern Europe, based on a large set of damage statistics. The observational database was obtained from post-earthquake surveys carried out in the area struck by the September 7, 1999 Athens earthquake. After analysis of the collected observational data, a unified damage database has been created which comprises 180,945 damaged buildings from/after the near-field area of the earthquake. The damaged buildings are classified in specific structural types, according to the materials, seismic codes and construction techniques in Southern Europe. The seismic demand is described in terms of both the regional macroseismic intensity and the ratio α g/ a o, where α g is the maximum peak ground acceleration (PGA) of the earthquake event and a o is the unique value PGA that characterizes each municipality shown on the Greek hazard map. The relative and cumulative frequencies of the different damage states for each structural type and each intensity level are computed in terms of damage ratio. Damage probability matrices (DPMs) and vulnerability curves are obtained for specific structural types. A comparison analysis is fulfilled between the produced and the existing vulnerability models.

Use of Remote Sensing Data to Enhance NWS Storm Damage Toolkit

Science.gov (United States)

Jedlove, Gary J.; Molthan, Andrew L.; White, Kris; Burks, Jason; Stellman, Keith; Smith, Mathew

2012-01-01

In the wake of a natural disaster such as a tornado, the National Weather Service (NWS) is required to provide a very detailed and timely storm damage assessment to local, state and federal homeland security officials. The Post ]Storm Data Acquisition (PSDA) procedure involves the acquisition and assembly of highly perishable data necessary for accurate post ]event analysis and potential integration into a geographic information system (GIS) available to its end users and associated decision makers. Information gained from the process also enables the NWS to increase its knowledge of extreme events, learn how to better use existing equipment, improve NWS warning programs, and provide accurate storm intensity and damage information to the news media and academia. To help collect and manage all of this information, forecasters in NWS Southern Region are currently developing a Storm Damage Assessment Toolkit (SDAT), which incorporates GIS ]capable phones and laptops into the PSDA process by tagging damage photography, location, and storm damage details with GPS coordinates for aggregation within the GIS database. However, this tool alone does not fully integrate radar and ground based storm damage reports nor does it help to identify undetected storm damage regions. In many cases, information on storm damage location (beginning and ending points, swath width, etc.) from ground surveys is incomplete or difficult to obtain. Geographic factors (terrain and limited roads in rural areas), manpower limitations, and other logistical constraints often prevent the gathering of a comprehensive picture of tornado or hail damage, and may allow damage regions to go undetected. Molthan et al. (2011) have shown that high resolution satellite data can provide additional valuable information on storm damage tracks to augment this database. This paper presents initial development to integrate satellitederived damage track information into the SDAT for near real ]time use by forecasters

Report on damaged FLIP TRIGA fuel

International Nuclear Information System (INIS)

Feltz, Donald E.; Randall, John D.; Schumacher, Robert F.

1977-01-01

Damaged FLIP elements were discovered, positioned adjacent to the transient rod. It then became apparent that this was not the failure of a defective, element but a heretofore unknown operating or design problem. The damaged elements are described as having bulges in the cladding and unevenly spaced dark rings along the fuelled portion of the element. Possible causes are investigated, including: defective fuel elements, incorrectly calculated power distributions in the core and in the elements, water leakage into the void follower of the transient rod, and improper safety limit for FLIP fuel. Based on measurements and calculations that have been experimentally verified it is concluded that the safety limit was not exceeded or even closely approached. It is also concluded that the problem is due entirely due to some phenomena occurring during pulsing, and that the steady state history of the fuel is not a factor

Increased sister chromatid cohesion and DNA damage response factor localization at an enzyme-induced DNA double-strand break in vertebrate cells.

LENUS (Irish Health Repository)

Dodson, Helen

2009-10-01

The response to DNA damage in vertebrate cells involves successive recruitment of DNA signalling and repair factors. We used light microscopy to monitor the genetic dependencies of such localization to a single, induced DNA double strand break (DSB) in vertebrate cells. We used an inducible version of the rare-cutting I-SceI endonuclease to cut a chromosomally integrated I-SceI site beside a Tet operator array that was visualized by binding a Tet repressor-GFP fusion. Formation of gamma-H2AX foci at a single DSB was independent of ATM or Ku70. ATM-deficient cells showed normal kinetics of 53Bp1 recruitment to DSBs, but Rad51 localization was retarded. 53Bp1 and Rad51 foci formation at a single DSB was greatly reduced in H2AX-null DT40 cells. We also observed decreased inter-sister chromatid distances after DSB induction, suggesting that cohesin loading at DSBs causes elevated sister chromatid cohesion. Loss of ATM reduced DSB-induced cohesion, consistent with cohesin being an ATM target in the DSB response. These data show that the same genetic pathways control how cells respond to single DSBs and to multiple lesions induced by whole-cell DNA damage.

A bacterial cytotoxin identifies the RhoA exchange factor Net1 as a key effector in the response to DNA damage.

Directory of Open Access Journals (Sweden)

Lina Guerra

Full Text Available BACKGROUND: Exposure of adherent cells to DNA damaging agents, such as the bacterial cytolethal distending toxin (CDT or ionizing radiations (IR, activates the small GTPase RhoA, which promotes the formation of actin stress fibers and delays cell death. The signalling intermediates that regulate RhoA activation and promote cell survival are unknown. PRINCIPAL FINDINGS: We demonstrate that the nuclear RhoA-specific Guanine nucleotide Exchange Factor (GEF Net1 becomes dephosphorylated at a critical inhibitory site in cells exposed to CDT or IR. Expression of a dominant negative Net1 or Net1 knock down by iRNA prevented RhoA activation, inhibited the formation of stress fibers, and enhanced cell death, indicating that Net1 activation is required for this RhoA-mediated responses to genotoxic stress. The Net1 and RhoA-dependent signals involved activation of the Mitogen-Activated Protein Kinase p38 and its downstream target MAPK-activated protein kinase 2. SIGNIFICANCE: Our data highlight the importance of Net1 in controlling RhoA and p38 MAPK mediated cell survival in cells exposed to DNA damaging agents and illustrate a molecular pathway whereby chronic exposure to a bacterial toxin may promote genomic instability.

Attenuation of the DNA Damage Response by Transforming Growth Factor-Beta Inhibitors Enhances Radiation Sensitivity of Non–Small-Cell Lung Cancer Cells In Vitro and In Vivo

Energy Technology Data Exchange (ETDEWEB)

Du, Shisuo; Bouquet, Sophie; Lo, Chen-Hao; Pellicciotta, Ilenia; Bolourchi, Shiva [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States); Parry, Renate [Varian Medical Systems, Palo Alto, California (United States); Barcellos-Hoff, Mary Helen, E-mail: mhbarcellos-hoff@nyumc.org [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States)

2015-01-01

Purpose: To determine whether transforming growth factor (TGF)-β inhibition increases the response to radiation therapy in human and mouse non–small-cell lung carcinoma (NSCLC) cells in vitro and in vivo. Methods and Materials: TGF-β–mediated growth response and pathway activation were examined in human NSCLC NCI-H1299, NCI-H292, and A549 cell lines and murine Lewis lung cancer (LLC) cells. Cells were treated in vitro with LY364947, a small-molecule inhibitor of the TGF-β type 1 receptor kinase, or with the pan-isoform TGF-β neutralizing monoclonal antibody 1D11 before radiation exposure. The DNA damage response was assessed by ataxia telangiectasia mutated (ATM) or Trp53 protein phosphorylation, γH2AX foci formation, or comet assay in irradiated cells. Radiation sensitivity was determined by clonogenic assay. Mice bearing syngeneic subcutaneous LLC tumors were treated with 5 fractions of 6 Gy and/or neutralizing or control antibody. Results: The NCI-H1299, A549, and LLC NSCLC cell lines pretreated with LY364947 before radiation exposure exhibited compromised DNA damage response, indicated by decreased ATM and p53 phosphorylation, reduced γH2AX foci, and increased radiosensitivity. The NCI-H292 cells were unresponsive. Transforming growth factor-β signaling inhibition in irradiated LLC cells resulted in unresolved DNA damage. Subcutaneous LLC tumors in mice treated with TGF-β neutralizing antibody exhibited fewer γH2AX foci after irradiation and significantly greater tumor growth delay in combination with fractionated radiation. Conclusions: Inhibition of TGF-β before radiation attenuated DNA damage recognition and increased radiosensitivity in most NSCLC cells in vitro and promoted radiation-induced tumor control in vivo. These data support the rationale for concurrent TGF-β inhibition and RT to provide therapeutic benefit in NSCLC.

Risk assessment of maize damage by wireworms (Coleoptera: Elateridae) as the first step in implementing IPM and in reducing the environmental impact of soil insecticides.

Science.gov (United States)

Furlan, L; Contiero, B; Chiarini, F; Colauzzi, M; Sartori, E; Benvegnù, I; Fracasso, F; Giandon, P

2017-01-01

A survey of maize fields was conducted in northeast Italy from 1986 to 2014, resulting in a dataset of 1296 records including information on wireworm damage to maize, plant-attacking species, agronomic characteristics, landscape and climate. Three wireworm species, Agriotes brevis Candeze, A. sordidus Illiger and A. ustulatus Schäller, were identified as the dominant pest species in maize fields. Over the 29-year period surveyed, no yield reduction was observed when wireworm plant damage was below 15 % of the stand. A preliminary univariate analysis of risk assessment was applied to identify the main factors influencing the occurrence of damage. A multifactorial model was then applied by using the significant factors identified. This model allowed the research to highlight the strongest factors and to analyse how the main factors together influenced damage risk. The strongest factors were: A. brevis as prevalent damaging species, soil organic matter content >5 %, rotation including meadows and/or double crops, A. sordidus as prevalent damaging species, and surrounding landscape mainly meadows, uncultivated grass and double crops. The multifactorial model also showed how the simultaneous occurrence of two or more of the aforementioned risk factors can conspicuously increase the risk of wireworm damage to maize crops, while the probability of damage to a field with no-risk factors is always low (<1 %). These results make it possible to draw risk maps to identify low-risk and high-risk areas, a first step in implementing bespoke IPM procedures in an attempt to reduce the impact of soil insecticides significantly.

Radiation damage of nonmetallic solids

International Nuclear Information System (INIS)

Goland, A.N.

1975-01-01

A review of data and information on radiation damage in nonmetallic solids is presented. Discussions are included on defects in nonmetals, radiation damage processes in nonmetals, electronic damage processes, physical damage processes, atomic displacement, photochemical damage processes, and ion implantation

Clustered DNA damage on subcellular level: effect of scavengers

Czech Academy of Sciences Publication Activity Database

Pachnerová Brabcová, Kateřina; Sihver, L.; Yasuda, N.; Matuo, Y.; Štěpán, Václav; Davídková, Marie

2014-01-01

Roč. 53, č. 4 (2014), s. 705-712 ISSN 0301-634X R&D Projects: GA MŠk LD12008 Institutional support: RVO:61389005 Keywords : clustered damage * indirect effects * haevy ion * plasmid in liquid water * scavenger Subject RIV: BO - Biophysics Impact factor: 1.528, year: 2014

Prevention of Noise Damage to Cochlear Synapses

Science.gov (United States)

2017-10-01

Assessment of synapse regeneration : Twelve week old CBA/CaJ mice are exposed to a moderate noise that destroys synapses on inner hair cells (IHCs) but spares...result of excitotoxic trauma to cochlear synapses due to glutamate released from the hair cells . Excitotoxic trauma damages the postsynaptic cell by...components ............................................. 12 d) Quantitative analysis of effects of neurotrophic factors on synapse regeneration in vitro

Integrated flood damage modelling in the Ebro river basin under hydrodynamic, socio-economic and environmental factors

Science.gov (United States)

Foudi, S.; Galarraga, I.; Osés, N.

2012-04-01

This paper presents a model of flood damage measurement. It studies the socio-economic and environmental potential damage of floods in the Ebro river basin. We estimate the damage to the urban, rural and environmental sectors. In these sectors, we make distinctions between residential, non residential, cultural, agricultural, public facilities and utilities, environmental and human subsectors. We focus on both the direct, indirect, tangible and intangible impacts. The residential damages refer to the damages on housing, costs of repair and cleaning as direct effects and the re-housing costs as an indirect effect. The non residential and agricultural impacts concern the losses to the economic sectors (industry, business, agricultural): production, capital losses, costs of cleaning and repairs for the direct costs and the consequences of the suspension of activities for the indirect costs. For the human sector, we refer to the physical impacts (injuries and death) in the direct tangible effects and to the posttraumatic stress as indirect intangible impact. The environmental impacts focus on a site of Community Interests (pSCIs) in the case study area. The case study is located the Ebro river basin, Spain. The Ebro river basin is the larger river basin in term of surface and water discharge. The Ebro river system is subject to Atlantic and Mediterranean climatic influences. It gathers most of its water from the north of Spain (in the Pyrenees Mountains) and is the most important river basin of Spain in term of water resources. Most of the flooding occurs during the winter period. Between 1900- 2010, the National Catalogue of Historical Floods identifies 372 events: meanly 33 events every 10 years and up to 58 during the 1990-2000. Natural floods have two origins: (i) persistent rainfalls in large sub basins raised up by high temperature giving rise to a rapid thaw in the Pyrenees, (ii) local rainfalls of short duration and high intensity that gives rise to rapid and

SCF analysis of a pressurized vessel-nozzle intersection with wall thinning damage

International Nuclear Information System (INIS)

Qadir, M.; Redekop, D.

2009-01-01

A three-dimensional finite element analysis is carried out of a pressurized vessel-nozzle intersection (tee joint), with wall thinning damage. A convergence-validation study is first carried out for undamaged intersections, in which comparisons are made with previously published work for the stress concentration factor (SCF), and good agreement is observed. A study is then carried out for specific tee joints to examine the effect on the SCF of varying the extent of the wall thinning damage. Finally, a parametric study is conducted in which the SCF is computed for a wide range of tee joints, initially considered undamaged, and then with wall thinning damage.

Tree-based flood damage modeling of companies: Damage processes and model performance

Science.gov (United States)

Sieg, Tobias; Vogel, Kristin; Merz, Bruno; Kreibich, Heidi

2017-07-01

Reliable flood risk analyses, including the estimation of damage, are an important prerequisite for efficient risk management. However, not much is known about flood damage processes affecting companies. Thus, we conduct a flood damage assessment of companies in Germany with regard to two aspects. First, we identify relevant damage-influencing variables. Second, we assess the prediction performance of the developed damage models with respect to the gain by using an increasing amount of training data and a sector-specific evaluation of the data. Random forests are trained with data from two postevent surveys after flood events occurring in the years 2002 and 2013. For a sector-specific consideration, the data set is split into four subsets corresponding to the manufacturing, commercial, financial, and service sectors. Further, separate models are derived for three different company assets: buildings, equipment, and goods and stock. Calculated variable importance values reveal different variable sets relevant for the damage estimation, indicating significant differences in the damage process for various company sectors and assets. With an increasing number of data used to build the models, prediction errors decrease. Yet the effect is rather small and seems to saturate for a data set size of several hundred observations. In contrast, the prediction improvement achieved by a sector-specific consideration is more distinct, especially for damage to equipment and goods and stock. Consequently, sector-specific data acquisition and a consideration of sector-specific company characteristics in future flood damage assessments is expected to improve the model performance more than a mere increase in data.

Clustered DNA damage induced by proton and heavy ion irradiation

International Nuclear Information System (INIS)

Davidkova, M.; Pachnerova Brabcova, K; Stepan, V.; Vysin, L.; Sihver, L.; Incerti, S.

2014-01-01

Ionizing radiation induces in DNA strand breaks, damaged bases and modified sugars, which accumulate with increasing density of ionizations in charged particle tracks. Compared to isolated DNA damage sites, the biological toxicity of damage clusters can be for living cells more severe. We investigated the clustered DNA damage induced by protons (30 MeV) and high LET radiation (C 290 MeV/u and Fe 500 MeV/u) in pBR322 plasmid DNA. To distinguish between direct and indirect pathways of radiation damage, the plasmid was irradiated in pure water or in aqueous solution of one of the three scavengers (coumarin-3-carboxylic acid, dimethylsulfoxide, and glycylglycine). The goal of the contribution is the analysis of determined types of DNA damage in dependence on radiation quality and related contribution of direct and indirect radiation effects. The yield of double strand breaks (DSB) induced in the DNA plasmid-scavenger system by heavy ion radiation was found to decrease with increasing scavenging capacity due to reaction with hydroxyl radical, linearly with high correlation coefficients. The yield of non-DSB clusters was found to occur twice as much as the DSB. Their decrease with increasing scavenging capacity had lower linear correlation coefficients. This indicates that the yield of non-DSB clusters depends on more factors, which are likely connected to the chemical properties of individual scavengers. (authors)

Fretting-wear damage of heat exchanger tubes: a proposed damage criterion based on tube vibration response

International Nuclear Information System (INIS)

Yetisir, M.; McKerrow, E.; Pettigrew, M.J.

1997-01-01

A simple criterion is proposed to estimate fretting-wear damage in heat exchanger tubes with clearance supports. The criterion is based on parameters such as vibration frequency, mid-span vibration amplitude, span length, tube mass and an empirical wear coefficient. It is generally accepted that fretting-wear damage is proportional to a parameter called work-rate. Work-rate is a measure of the dynamic interaction between a vibrating tube and its supports. Due to the complexity of the impact-sliding behavior at the clearance-supports, work-rate calculations for heat exchanger tubes require specialized non-linear finite element codes. These codes include contact models for various clearance-support geometries. Such non-linear finite element analyses are complex, expensive and time consuming. The proposed criterion uses the results of linear vibration analysis (i.e., vibration frequency and mid-span vibration amplitude due to turbulence) and does not require a non-linear analysis. It can be used by non-specialists for a quick evaluation of the expected work-rate, and hence, the fretting-wear damage of heat exchanger tubes. The proposed criterion was obtained from an extensive parametric study that was conducted using a non-linear finite element program. It is shown that, by using the proposed work-rate criteria, work-rate can be estimated within a factor of two. This result, however, requires further testing with more complicated flow patterns. (author)

Flood damage estimation of companies: A comparison of Stage-Damage-Functions and Random Forests

Science.gov (United States)

Sieg, Tobias; Kreibich, Heidi; Vogel, Kristin; Merz, Bruno

2017-04-01

The development of appropriate flood damage models plays an important role not only for the damage assessment after an event but also to develop adaptation and risk mitigation strategies. So called Stage-Damage-Functions (SDFs) are often applied as a standard approach to estimate flood damage. These functions assign a certain damage to the water depth depending on the use or other characteristics of the exposed objects. Recent studies apply machine learning algorithms like Random Forests (RFs) to model flood damage. These algorithms usually consider more influencing variables and promise to depict a more detailed insight into the damage processes. In addition they provide an inherent validation scheme. Our study focuses on direct, tangible damage of single companies. The objective is to model and validate the flood damage suffered by single companies with SDFs and RFs. The data sets used are taken from two surveys conducted after the floods in the Elbe and Danube catchments in the years 2002 and 2013 in Germany. Damage to buildings (n = 430), equipment (n = 651) as well as goods and stock (n = 530) are taken into account. The model outputs are validated via a comparison with the actual flood damage acquired by the surveys and subsequently compared with each other. This study investigates the gain in model performance with the use of additional data and the advantages and disadvantages of the RFs compared to SDFs. RFs show an increase in model performance with an increasing amount of data records over a comparatively large range, while the model performance of the SDFs is already saturated for a small set of records. In addition, the RFs are able to identify damage influencing variables, which improves the understanding of damage processes. Hence, RFs can slightly improve flood damage predictions and provide additional insight into the underlying mechanisms compared to SDFs.

DNA damage and autophagy

International Nuclear Information System (INIS)

Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely; Panayiotidis, Mihalis I.; Franco, Rodrigo

2011-01-01

Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.

Study on quantitative risk assessment model of the third party damage for natural gas pipelines based on fuzzy comprehensive assessment

International Nuclear Information System (INIS)

Qiu, Zeyang; Liang, Wei; Lin, Yang; Zhang, Meng; Wang, Xue

2017-01-01

As an important part of national energy supply system, transmission pipelines for natural gas are possible to cause serious environmental pollution, life and property loss in case of accident. The third party damage is one of the most significant causes for natural gas pipeline system accidents, and it is very important to establish an effective quantitative risk assessment model of the third party damage for reducing the number of gas pipelines operation accidents. Against the third party damage accident has the characteristics such as diversity, complexity and uncertainty, this paper establishes a quantitative risk assessment model of the third party damage based on Analytic Hierarchy Process (AHP) and Fuzzy Comprehensive Evaluation (FCE). Firstly, risk sources of third party damage should be identified exactly, and the weight of factors could be determined via improved AHP, finally the importance of each factor is calculated by fuzzy comprehensive evaluation model. The results show that the quantitative risk assessment model is suitable for the third party damage of natural gas pipelines and improvement measures could be put forward to avoid accidents based on the importance of each factor. (paper)

Exploring the potential of multivariate depth-damage and rainfall-damage models

DEFF Research Database (Denmark)

van Ootegem, Luc; van Herck, K.; Creten, T.

2018-01-01

In Europe, floods are among the natural catastrophes that cause the largest economic damage. This article explores the potential of two distinct types of multivariate flood damage models: ‘depth-damage’ models and ‘rainfall-damage’ models. We use survey data of 346 Flemish households that were...... victim of pluvial floods complemented with rainfall data from both rain gauges and weather radars. In the econometrical analysis, a Tobit estimation technique is used to deal with the issue of zero damage observations. The results show that in the ‘depth-damage’ models flood depth has a significant...... impact on the damage. In the ‘rainfall-damage’ models there is a significant impact of rainfall accumulation on the damage when using the gauge rainfall data as predictor, but not when using the radar rainfall data. Finally, non-hazard indicators are found to be important for explaining pluvial flood...

HERCulean giant orchestrates ubiquitin-mediated signaling on damaged chromosomes

Czech Academy of Sciences Publication Activity Database

Hodný, Zdeněk; Mistrik, M.; Bartek, Jiří

2010-01-01

Roč. 9, č. 7 (2010), s. 1227-1228 ISSN 1538-4101 R&D Projects: GA ČR GA301/08/0353 Institutional research plan: CEZ:AV0Z50520514 Keywords : DNA damage response * HERC2 * ubiquitylation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.999, year: 2010

Label-free electrochemical detection of singlet oxygen protein damage

Czech Academy of Sciences Publication Activity Database

Vargová, Veronika; Gimenez, R.E.; Černocká, Hana; Trujillo, D.C.; Tulli, F.; Zanini, V.I.P.; Paleček, Emil; Borsarelli, C.D.; Ostatná, Veronika

2016-01-01

Roč. 187, JAN 2016 (2016), s. 662-669 ISSN 0013-4686 R&D Projects: GA ČR GA13-00956S Institutional support: RVO:68081707 Keywords : singlet oxygen protein damage * surface-attached protein stability * mercury and carbon electrodes Subject RIV: BO - Biophysics Impact factor: 4.798, year: 2016

SUMO boosts the DNA damage response barrier against cancer

Czech Academy of Sciences Publication Activity Database

Bartek, Jiří; Hodný, Zdeněk

2010-01-01

Roč. 17, č. 1 (2010), s. 9-11 ISSN 1535-6108 R&D Projects: GA ČR GA301/08/0353 Institutional research plan: CEZ:AV0Z50520514 Keywords : DNA damage response * ubiquitylation * sumoylation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 26.925, year: 2010

New elements of molecular orchestra at radiation-induced damaged genomic sites

International Nuclear Information System (INIS)

Wani, Altaf A.; Battu, Aruna; Ray, Alo

2012-01-01

DNA damage promptly activates cell cycle checkpoints enabling cells to repair their genome. ATR and ATM kinases are central to the checkpoint activation in response to DNA damage and replication stress. Activated ATR and ATM phosphorylate several downstream proteins involved in DNA repair and cell cycle arrest. However, the nature of the signal, which initially activates these kinases in response to UV damage and how they interact with nucleotide excision repair (NER) pathway, is unclear. Our research has shown that DDB2 and XPC, two early damage recognition factors, promoted ATR and ATM recruitment and phosphorylation. ATR and ATM localized to the damage site and physically interact with XPC. ATR and ATM recruitment and their phosphorylation is negatively affected in cells defective in DDB2 and XPC functions while conversely ATR- and ATM-deficiency fail to influence the damage recruitment of DDB2 and XPC proteins. Consequently, the phosphorylation of ATR and ATM substrates, Chk1, Chk2, H2AX, and BRCA1 is significantly reduced or abrogated in mutant cells, indicating that defective DDB2 and XPC function impaired the checkpoint signal transduction cascade in response to UV damage. DDB2 and XPC also regulated the BRCA1 and Rad51 recruitment to the damage site, implicating their role in homologous recombination-mediated DNA repair pathway. Supporting data reveal that the depletion of ATR and ATM influenced the NER efficiency. Moreover, upon completion of NER, ordered restoration of chromatin structure and key epigenetic marks are necessary for resumption of the cell's normal function. We have demonstrated such a restoration role of H3K56 acetylation (H3K56Ac) mark in response to UV irradiation, In human cells a fast initial deacetylation of H3K56 is followed by full renewal of an acetylated state at ∼ 24-48 hr post-irradiation. Histone chaperone, anti-silencing function-1A (ASF1A), is crucial for post-repair H3K56Ac restoration, which in turn, is needed for the

β2-Adrenergic Receptor-Mediated HIF-1α Upregulation Mediates Blood Brain Barrier Damage in Acute Cerebral Ischemia

Directory of Open Access Journals (Sweden)

Yanyun Sun

2017-08-01

Full Text Available Disruption of the blood brain barrier (BBB within the thrombolytic time window is an antecedent event to intracerebral hemorrhage in ischemic stroke. Our recent studies showed that 2-h cerebral ischemia induced BBB damage in non-infarcted area and secreted matrix metalloproteinase-2 (MMP-2 accounted for this disruption. However, the factors that affect MMP-2 secretion and regulate BBB damage remains unknown. Since hypoxia-inducible factor-1 alpha (HIF-1α was discovered as a mater regulator in hypoxia, we sought to investigate the roles of HIF-1α in BBB damage as well as the factors regulating HIF-1α expression in the ischemic brain. in vivo rat middle cerebral artery occlusion (MCAO and in vitro oxygen glucose deprivation (OGD models were used to mimic ischemia. Pretreatment with HIF-1α inhibitor YC-1 significantly inhibited 2-h MCAO-induced BBB damage, which was accompanied by suppressed occludin degradation and vascular endothelial growth factor (VEGF mRNA upregulation. Interestingly, β2-adrenergic receptor (β2-AR antagonist ICI 118551 attenuated ischemia-induced BBB damage by regulating HIF-1α expression. Double immunostaining showed that HIF-1α was upregulated in ischemic neurons but not in astrocytes andendothelial cells. Of note, HIF-1α inhibition with inhibitor YC-1 or siRNA significantly prevented OGD-induced VEGF upregulation as well as the secretion of VEGF and MMP-2 in neurons. More importantly, blocking β2-AR with ICI 118551 suppressedHIF-1α upregulation in ischemic neurons and attenuated occludin degradation induced by the conditioned media of OGD-treatedneurons. Taken together, blockade of β2-AR-mediated HIF-1α upregulation mediates BBB damage during acute cerebral ischemia. These findings provide new mechanistic understanding of early BBB damage in ischemic stroke and may help reduce thrombolysis-related hemorrhagic complications.

Structural Health Management of Damaged Aircraft Structures Using the Digital Twin Concept

Science.gov (United States)

Seshadri, Banavara R.; Krishnamurthy, Thiagarajan

2017-01-01

The development of multidisciplinary integrated Structural Health Management (SHM) tools will enable accurate detection, and prognosis of damaged aircraft under normal and adverse conditions during flight. As part of the digital twin concept, methodologies are developed by using integrated multiphysics models, sensor information and input data from an in-service vehicle to mirror and predict the life of its corresponding physical twin. SHM tools are necessary for both damage diagnostics and prognostics for continued safe operation of damaged aircraft structures. The adverse conditions include loss of control caused by environmental factors, actuator and sensor faults or failures, and structural damage conditions. A major concern in these structures is the growth of undetected damage/cracks due to fatigue and low velocity foreign object impact that can reach a critical size during flight, resulting in loss of control of the aircraft. To avoid unstable, catastrophic propagation of damage during a flight, load levels must be maintained that are below a reduced load-carrying capacity for continued safe operation of an aircraft. Hence, a capability is needed for accurate real-time predictions of damage size and safe load carrying capacity for structures with complex damage configurations. In the present work, a procedure is developed that uses guided wave responses to interrogate damage. As the guided wave interacts with damage, the signal attenuates in some directions and reflects in others. This results in a difference in signal magnitude as well as phase shifts between signal responses for damaged and undamaged structures. Accurate estimation of damage size, location, and orientation is made by evaluating the cumulative signal responses at various pre-selected sensor locations using a genetic algorithm (GA) based optimization procedure. The damage size, location, and orientation is obtained by minimizing the difference between the reference responses and the

Primary DNA Damage in Dry Cleaners with Perchlorethylene Exposure

Directory of Open Access Journals (Sweden)

Mohammad Azimi

2017-10-01

Full Text Available Background: Perchloroethylene is a halogenated solvent widely used in dry cleaning. International agency of research on cancer classified this chemical as a probable human carcinogen. Objective: To evaluate the extent of primary DNA damage in dry cleaner workers who were exposed to perchloroethylene as compared to non-exposed subjects. The effect of exposure modifying factors such as use of personal protective equipment, perceived risk, and reported safe behaviors on observed DNA damage were also studied. Methods: 59 exposed and non-exposed workers were selected from Yazd, Iran. All the 33 exposed workers had work history at least 3 months in the dry cleaning shops. Peripheral blood sampling was performed. Microscope examination was performed under fluorescent microscope (400×. Open comet software was used for image analysis. All biological analysis was performed in one laboratory. Results: Primary DNA damage to leukocytes in dry cleaners was relatively high. The median tail length, %DNA in tail, and tail moment in exposed group were significantly higher than those in non-exposed group. There was no significant difference between smokers and nonsmokers in terms of tail length, tail moment, and %DNA in tail. There was no significant correlation between duration of employment in dry cleaning and observed DNA damage in terms of tail length, tail moment and %DNA in tail. Stratified analysis based on exposed and nonexposed category showed no significant relationship between age and observed DNA damage. Conclusion: Occupationally exposure to perchloroethylene can cause early DNA damage in dry cleaners.

In Vivo Damage of the Head-Neck Junction in Hard-on-Hard Total Hip Replacements: Effect of Femoral Head Size, Metal Combination, and 12/14 Taper Design

Directory of Open Access Journals (Sweden)

Massimiliano Baleani

2017-07-01

Full Text Available Recently, concerns have been raised about the potential effect of head-neck junction damage products at the local and systemic levels. Factors that may affect this damage process have not been fully established yet. This study investigated the possible correlations among head-neck junction damage level, implant design, material combination, and patient characteristics. Head-neck junctions of 148 retrieved implants were analysed, including both ceramic-on-ceramic (N = 61 and metal-on-metal (N = 87 bearings. In all cases, the male taper was made of titanium alloy. Damage was evaluated using a four-point scoring system based on damage morphology and extension. Patient age at implantation, implantation time, damage risk factor, and serum ion concentration were considered as independent potential predicting variables. The damage risk factor summarises head-neck design characteristics and junction loading condition. Junction damage correlated with both implantation time and damage factor risk when the head was made of ceramic. A poor correlation was found when the head was made of cobalt alloy. The fretting-corrosion phenomenon seemed mainly mechanically regulated, at least when cobalt alloy components were not involved. When a component was made of cobalt alloy, the role of chemical phenomena increased, likely becoming, over implantation time, the damage driving phenomena of highly stressed junctions.

Damage Detection for Historical Architectures Based on Tls Intensity Data

Science.gov (United States)

Li, Q.; Cheng, X.

2018-04-01

TLS (Terrestrial Laser Scanner) has long been preferred in the cultural heritage field for 3D documentation of historical sites thanks to its ability to acquire the geometric information without any physical contact. Besides the geometric information, most TLS systems also record the intensity information, which is considered as an important measurement of the spectral property of the scanned surface. Recent studies have shown the potential of using intensity for damage detection. However, the original intensity is affected by scanning geometry such as range and incidence angle and other factors, thus making the results less accurate. Therefore, in this paper, we present a method to detect certain damage areas using the corrected intensity data. Firstly, two data-driven models have been developed to correct the range and incidence angle effect. Then the corrected intensity is used to generate 2D intensity images for classification. After the damage areas being detected, they are re-projected to the 3D point cloud for better visual representation and further investigation. The experiment results indicate the feasibility and validity of the corrected intensity for damage detection.

DNA-repair, cell killing and normal tissue damage

International Nuclear Information System (INIS)

Dahm-Daphi, J.; Dikomey, E.; Brammer, I.

1998-01-01

Background: Side effects of radiotherapy in normal tissue is determined by a variety of factors of which cellular and genetic contributions are described here. Material and methods: Review. Results: Normal tissue damage after irradiation is largely due to loss of cellular proliferative capacity. This can be due to mitotic cell death, apoptosis, or terminal differentiation. Dead or differentiated cells release cytokines which additionally modulate the tissue response. DNA damage, in particular non-reparable or misrepaired double-strand breaks are considered the basic lesion leading to G1-arrest and ultimately to cell inactivation. Conclusion: Evidence for genetic bases of normal tissue response, cell killing and DNA-repair capacity is presented. However, a direct link of all 3 endpoints has not yet been proved directly. (orig.) [de

Hepatoprotective effect of methanolic Tanacetum parthenium extract on CCl4-induced liver damage in rats

Directory of Open Access Journals (Sweden)

Yavar Mahmoodzadeh

Full Text Available The purpose of this study was to investigate the effects of Tanacetum Parthenium Extract (TPE on Lipid peroxidation, antioxidant enzymes, biochemical factors, and liver enzymes in the rats damaged by Carbon Tetrachloride (CCl4.54 male Wistar rats were divided into 9 groups each consisting of 6 rats. Two of the groups were control groups (normal and damage control groups, 4 of them were exposure groups which were respectively administered with 40, 80, and 120 mg/kg of TPE and silymarin for 14 days before being damaged by CCl4, and the other 3 groups were post-treatment groups which received 80 and 120 mg/kg of TPE and silymarin 2, 6, 24, and 48 h after being injected with CCl4. At the end of the study, biochemical factors, serum liver enzymes, malondialdehyde level, antioxidant enzymes, and liver morphology were assayed.Pre- and post-treatment with TPE could significantly decrease ALT, AST, ALP, TG, LDL, TC, and glucose levels and increase HDL, and albumin levels and catalase, SOD, and GPx activities compared to the CCl4-damaged control group.The results of this study are indicative of the antioxidant activity of TPE, its potential hepatoprotective effects, and its probable therapeutic properties for laboratory animals damaged by CCl4. Keywords: Tanacetum parthenium, Carbon tetrachloride, Oxidative stress, Antioxidant enzymes, Liver damage

Estrogen signalling and the DNA damage response in hormone dependent breast cancers

Directory of Open Access Journals (Sweden)

C Elizabeth Caldon

2014-05-01

Full Text Available Estrogen is necessary for the normal growth and development of breast tissue, but high levels of estrogen are a major risk factor for breast cancer. One mechanism by which estrogen could contribute to breast cancer is via the induction of DNA damage. This perspective discusses the mechanisms by which estrogen alters the DNA damage response (DDR and DNA repair through the regulation of key effector proteins including ATM, ATR, CHK1, BRCA1 and p53 and the feedback on estrogen receptor signalling from these proteins. We put forward the hypothesis that estrogen receptor signalling converges to suppress effective DNA repair and apoptosis in favour of proliferation. This is important in hormone-dependent breast cancer as it will affect processing of estrogen-induced DNA damage, as well as other genotoxic insults. DDR and DNA repair proteins are frequently mutated or altered in estrogen responsive breast cancer which will further change the processing of DNA damage. Finally the action of estrogen signalling on DNA damage is also relevant to the therapeutic setting as the suppression of a DNA damage response by estrogen has the potential to alter the response of cancers to anti-hormone treatment or chemotherapy that induces DNA damage.

The omega-3 fatty acid, eicosapentaenoic acid (EPA, prevents the damaging effects of tumour necrosis factor (TNF-alpha during murine skeletal muscle cell differentiation

Directory of Open Access Journals (Sweden)

Pearson Stephen

2008-07-01

Full Text Available Abstract Background Eicosapentaenoic acid (EPA is a ώ-3 polyunsaturated fatty acid with anti-inflammatory and anti-cachetic properties that may have potential benefits with regards to skeletal muscle atrophy conditions where inflammation is present. It is also reported that pathologic levels of the pro-inflammatory cytokine tumour necrosis factor (TNF-α are associated with muscle wasting, exerted through inhibition of myogenic differentiation and enhanced apoptosis. These findings led us to hypothesize that EPA may have a protective effect against skeletal muscle damage induced by the actions of TNF-α. Results The deleterious effects of TNF-α on C2C12 myogenesis were completely inhibited by co-treatment with EPA. Thus, EPA prevented the TNF-mediated loss of MyHC expression and significantly increased myogenic fusion (p p p p p p Conclusion In conclusion, EPA has a protective action against the damaging effects of TNF-α on C2C12 myogenesis. These findings support further investigations of EPA as a potential therapeutic agent during skeletal muscle regeneration following injury.

Spatial variations of damage parameters in FMIT and their implications

International Nuclear Information System (INIS)

Schiffgens, J.O.; Simons, R.L.; Mann, F.M.; Carter, L.L.

1978-12-01

The major conclusion is that the variation in damage rates in FMIT will be dominated by changes in flux, not spectrum. Throughout the test region where the flux is greater than 10 14 n/cm 2 .s, the flux varies by a factor of about 20, while the spectral-averaged displacement and helium production cross sections for copper vary by less than factors of two and four, respectively. The corresponding helium-to-dpa ratios bracket a fusion reactor first wall value for copper (i.e., 7.7 appm He/dpa). With the Li(d,n) yields and copper damage energy and helium production cross sections used in this study, the test volumes for which the displacement and total helium production rates are greater than those at a D-T fusion reactor first wall, with a loading of 1.25 MW/m 2 , are about 100 and 130 cm 3 , respectively

Radiation-induced damage of membranes

International Nuclear Information System (INIS)

Yonei, Shuji

1977-01-01

An outline of membranous structure was stated, and radiation-induced damage of membranes were surveyed. By irradiation, permeability of membranes, especially passive transportation mechanism, was damaged, and glycoprotein in the surface layers of cells and the surface layer structures were changed. The intramembranous damage was induced by decrease of electrophoresis of nuclear mambranes and a quantitative change of cytochrome P450 of microsomal membranes of the liver, and peroxidation of membranous lipid and SH substitute damage of membranous protein were mentioned as the mechanism of membranous damage. Recovery of membranous damage depends on radiation dose and temperature, and membranous damage participates largely in proliferation death. (tsunoda, M.)

DNA damage mediated transcription arrest: Step back to go forward.

Science.gov (United States)

Mullenders, Leon

2015-12-01

The disturbance of DNA helix conformation by bulky DNA damage poses hindrance to transcription elongating due to stalling of RNA polymerase at transcription blocking lesions. Stalling of RNA polymerase provokes the formation of R-loops, i.e. the formation of a DNA-RNA hybrid and a displaced single stranded DNA strand as well as displacement of spliceosomes. R-loops are processed into DNA single and double strand breaks by NER factors depending on TC-NER factors leading to genome instability. Moreover, stalling of RNA polymerase induces a strong signal for cell cycle arrest and apoptosis. These toxic and mutagenic effects are counteracted by a rapid recruitment of DNA repair proteins to perform transcription coupled nucleotide excision repair (TC-NER) to remove the blocking DNA lesions and to restore transcription. Recent studies have highlighted the role of backtracking of RNA polymerase to facilitate TC-NER and identified novel factors that play key roles in TC-NER and in restoration of transcription. On the molecular level these factors facilitate stability of the repair complex by promotion and regulation of various post-translational modifications of NER factors and chromatin substrate. In addition, the continuous flow of new factors that emerge from screening assays hints to several regulatory levels to safeguard the integrity of transcription elongation after disturbance by DNA damage that have yet to be explored. Copyright © 2015 Elsevier B.V. All rights reserved.

Multivariate pluvial flood damage models

International Nuclear Information System (INIS)

Van Ootegem, Luc; Verhofstadt, Elsy; Van Herck, Kristine; Creten, Tom

2015-01-01

Depth–damage-functions, relating the monetary flood damage to the depth of the inundation, are commonly used in the case of fluvial floods (floods caused by a river overflowing). We construct four multivariate damage models for pluvial floods (caused by extreme rainfall) by differentiating on the one hand between ground floor floods and basement floods and on the other hand between damage to residential buildings and damage to housing contents. We do not only take into account the effect of flood-depth on damage, but also incorporate the effects of non-hazard indicators (building characteristics, behavioural indicators and socio-economic variables). By using a Tobit-estimation technique on identified victims of pluvial floods in Flanders (Belgium), we take into account the effect of cases of reported zero damage. Our results show that the flood depth is an important predictor of damage, but with a diverging impact between ground floor floods and basement floods. Also non-hazard indicators are important. For example being aware of the risk just before the water enters the building reduces content damage considerably, underlining the importance of warning systems and policy in this case of pluvial floods. - Highlights: • Prediction of damage of pluvial floods using also non-hazard information • We include ‘no damage cases’ using a Tobit model. • The damage of flood depth is stronger for ground floor than for basement floods. • Non-hazard indicators are especially important for content damage. • Potential gain of policies that increase awareness of flood risks

Multivariate pluvial flood damage models

Energy Technology Data Exchange (ETDEWEB)

Van Ootegem, Luc [HIVA — University of Louvain (Belgium); SHERPPA — Ghent University (Belgium); Verhofstadt, Elsy [SHERPPA — Ghent University (Belgium); Van Herck, Kristine; Creten, Tom [HIVA — University of Louvain (Belgium)

2015-09-15

Depth–damage-functions, relating the monetary flood damage to the depth of the inundation, are commonly used in the case of fluvial floods (floods caused by a river overflowing). We construct four multivariate damage models for pluvial floods (caused by extreme rainfall) by differentiating on the one hand between ground floor floods and basement floods and on the other hand between damage to residential buildings and damage to housing contents. We do not only take into account the effect of flood-depth on damage, but also incorporate the effects of non-hazard indicators (building characteristics, behavioural indicators and socio-economic variables). By using a Tobit-estimation technique on identified victims of pluvial floods in Flanders (Belgium), we take into account the effect of cases of reported zero damage. Our results show that the flood depth is an important predictor of damage, but with a diverging impact between ground floor floods and basement floods. Also non-hazard indicators are important. For example being aware of the risk just before the water enters the building reduces content damage considerably, underlining the importance of warning systems and policy in this case of pluvial floods. - Highlights: • Prediction of damage of pluvial floods using also non-hazard information • We include ‘no damage cases’ using a Tobit model. • The damage of flood depth is stronger for ground floor than for basement floods. • Non-hazard indicators are especially important for content damage. • Potential gain of policies that increase awareness of flood risks.

Regionalized life cycle impact assessment of air pollution on the global scale: Damage to human health and vegetation

Science.gov (United States)

van Zelm, Rosalie; Preiss, Philipp; van Goethem, Thomas; Van Dingenen, Rita; Huijbregts, Mark

2016-06-01

We developed regionalized characterization factors (CFs) for human health damage from particulate matter (PM2.5) and ozone, and for damage to vegetation from ozone, at the global scale. These factors can be used in the impact assessment phase of an environmental life cycle assessment. CFs express the overall damage of a certain pollutant per unit of emission of a precursor, i.e. primary PM2.5, nitrogen oxides (NOx), ammonia (NH3), sulfur dioxide (SO2) and non-methane volatile organic compounds (NMVOCs). The global chemical transport model TM5 was used to calculate intake fractions of PM2.5 and ozone for 56 world regions covering the whole globe. Furthermore, region-specific effect and damage factors were derived, using mortality rates, background concentrations and years of life lost. The emission-weighted world average CF for primary PM2.5 emissions is 629 yr kton-1, varying up to 3 orders of magnitude over the regions. Larger CFs were obtained for emissions in central Asia and Europe, and smaller factors in Australia and South America. The world average CFs for PM2.5 from secondary aerosols, i.e. NOx, NH3, and SO2, is 67.2 to 183.4 yr kton-1. We found that the CFs for ozone human health damage are 2-4 orders of magnitude lower compared to the CFs for damage due to primary PM2.5 and PM2.5 precursor emissions. Human health damage due to the priority air pollutants considered in this study was 1.7·10-2 yr capita-1 worldwide in year 2010, with primary PM2.5 emissions as the main contributor (62%). The emission-weighted world average CF for ecosystem damage due to ozone was 2.5 km2 yr kton-1 for NMVOCs and 8.7 m2 yr kg-1 for NOx emissions, varying 2-3 orders of magnitude over the regions. Ecosystem damage due to the priority air pollutants considered in this study was 1.6·10-4 km2 capita-1 worldwide in 2010, with NOx as the main contributor (72%). The spatial range in CFs stresses the importance of including spatial variation in life cycle impact assessment of

Reproductive-phase and interphase lethal cell damage after irradiation and treatment with cytostatics

International Nuclear Information System (INIS)

Hagemann, G.

1979-01-01

After X-ray irradiation of manual cells, two lethal fractions occur due to reproductive and interphase death under low and high radiation doses. The damage kinetics on which this fact is based is compared with hypothetical tumour frequencies and leucemia induction caused in experiments. The reproductive-lethal damage can be manifested by means of colony size spectrometry, with the median colony size class differences (MCD) serving as measure for the damage found. The simultaneous effects of the cytostatics BLEOMYCIN or ICRF 159 and X-rays on reproductive lethal and interphase-lethal damage are measured by means of MCD and survival fraction, and the additive and intensifying effect' is judged with the help of suitably defined terms. This shows that the clinically used ICRF 159 has an additive effect on interphase-lethal and a sub-additive effect on reproductive-lethal cell damage. Thus, favourable results may be expected for the electivity factor in fractionated irradiation and with regard to delayed damage in healthy tissue. (orig.) 891 MG/orig. 892 RDG [de

Structural Stability of Human Fibroblast Growth Factor-1 Is Essential for Protective Effects Against Radiation-Induced Intestinal Damage

Energy Technology Data Exchange (ETDEWEB)

Nakayama, Fumiaki, E-mail: f_naka@nirs.go.jp [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Umeda, Sachiko [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Yasuda, Takeshi [Department of Radiation Emergency Medicine, Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba (Japan); Asada, Masahiro; Motomura, Kaori; Suzuki, Masashi [Signaling Molecules Research Laboratory, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki (Japan); Zakrzewska, Malgorzata [Faculty of Biotechnology, University of Wroclaw (Poland); Imamura, Toru [Signaling Molecules Research Laboratory, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki (Japan); Imai, Takashi [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan)

2013-02-01

Purpose: Human fibroblast growth factor-1 (FGF1) has radioprotective effects on the intestine, although its structural instability limits its potential for practical use. Several stable FGF1 mutants were created increasing stability in the order, wild-type FGF1, single mutants (Q40P, S47I, and H93G), Q40P/S47I, and Q40P/S47I/H93G. This study evaluated the contribution of the structural stability of FGF1 to its radioprotective effect. Methods and Materials: Each FGF1 mutant was administered intraperitoneally to BALB/c mice in the absence of heparin 24 h before or after total body irradiation (TBI) with {gamma}-rays at 8-12 Gy. Several radioprotective effects were examined in the jejunum. Results: Q40P/S47I/H93G could activate all subtypes of FGF receptors in vitro much more strongly than the wild-type without endogenous or exogenous heparin. Preirradiation treatment with Q40P/S47I/H93G significantly increased crypt survival more than wild-type FGF1 after TBI at 10 or 12 Gy, and postirradiation treatment with Q40P/S47I/H93G was effective in promoting crypt survival after TBI at 10, 11, or 12 Gy. In addition, crypt cell proliferation, crypt depth, and epithelial differentiation were significantly promoted by postirradiation treatment with Q40P/S47I/H93G. The level of stability of FGF1 mutants correlated with their mitogenic activities in vitro in the absence of heparin; however, preirradiation treatment with the mutants increased the crypt number to almost the same level as Q40P/S47I/H93G. When given 24 h after TBI at 10 Gy, all FGF1 mutants increased crypt survival more than wild-type FGF1, and Q40P/S47I/H93G had the strongest mitogenic effects in intestinal epithelial cells after radiation damage. Moreover, Q40P/S47I/H93G prolonged mouse survival after TBI because of the repair of intestinal damage. Conclusion: These findings suggest that the structural stability of FGF1 can contribute to the enhancement of protective effects against radiation-induced intestinal

Local damage to reinforced concrete structures caused by impact of aircraft engine missiles. Pt. 2

International Nuclear Information System (INIS)

Sugano, T.; Tsubota, H.; Kasai, Y.; Koshika, N.; Itoh, C.; Shirai, K.; Von Riesemann, W.A.; Bickel, D.C.; Parks, M.B.

1993-01-01

Three sets of impact tests, small-, intermediate-, and full-scale tests, have been executed to determine local damage to reinforced concrete structures caused by the impact of aircraft engine missiles. The results of the test program showed that (1) the use of the similarity law is appropriate, (2) suitable empirical formulas exist for predicting the local damage caused by rigid missiles, (3) reduction factors may be used for evaluating the reduction in local damage due to the deformability of the engines, (4) the reinforcement ratio has no effect on local damage, and (5) the test results could be adequately predicted using nonlinear response analysis. (orig.)

Detecting DNA damage with a silver solid amalgam electrode

Czech Academy of Sciences Publication Activity Database

Kuchaříková, Kateřina; Novotný, Ladislav; Josypčuk, Bohdan; Fojta, Miroslav

2004-01-01

Roč. 16, č. 5 (2004), s. 410-414 ISSN 1040-0397 R&D Projects: GA AV ČR IAA4004108; GA AV ČR IBS5004355 Institutional research plan: CEZ:AV0Z5004920 Keywords : DNA damage * silver solid amalgam electrode * HMDE Subject RIV: BO - Biophysics Impact factor: 2.038, year: 2004

A diagnostic ontological model for damages to historical constructions

Czech Academy of Sciences Publication Activity Database

Cacciotti, Riccardo; Blaško, M.; Valach, Jaroslav

2015-01-01

Roč. 16, č. 1 (2015), s. 40-48 ISSN 1296-2074 R&D Projects: GA MK(CZ) DF11P01OVV002 Keywords : historical constructions * conservation * ontologies * damage Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 1.533, year: 2015 http://www.sciencedirect.com/science/article/pii/S1296207414000259

DNA damage and polyploidization.

Science.gov (United States)

Chow, Jeremy; Poon, Randy Y C

2010-01-01

A growing body of evidence indicates that polyploidization triggers chromosomal instability and contributes to tumorigenesis. DNA damage is increasingly being recognized for its roles in promoting polyploidization. Although elegant mechanisms known as the DNA damage checkpoints are responsible for halting the cell cycle after DNA damage, agents that uncouple the checkpoints can induce unscheduled entry into mitosis. Likewise, defects of the checkpoints in several disorders permit mitotic entry even in the presence of DNA damage. Forcing cells with damaged DNA into mitosis causes severe chromosome segregation defects, including lagging chromosomes, chromosomal fragments and chromosomal bridges. The presence of these lesions in the cleavage plane is believed to abort cytokinesis. It is postulated that if cytokinesis failure is coupled with defects of the p53-dependent postmitotic checkpoint pathway, cells can enter S phase and become polyploids. Progress in the past several years has unraveled some of the underlying principles of these pathways and underscored the important role of DNA damage in polyploidization. Furthermore, polyploidization per se may also be an important determinant of sensitivity to DNA damage, thereby may offer an opportunity for novel therapies.

Computer simulations of radiation damage in protein crystals; Simulationsrechnungen zu Strahlenschaeden an Proteinkristallen

Energy Technology Data Exchange (ETDEWEB)

Zehnder, M

2007-03-15

The achievable resolution and the quality of the dataset of an intensity data collection for structure analysis of protein crystals with X-rays is limited among other factors by radiation damage. The aim of this work is to obtain a better quantitative understanding of the radiation damage process in proteins. Since radiation damage is unavoidable it was intended to look for the optimum ratio between elastically scattered intensity and radiation damage. Using a Monte Carlo algorithm physical processes after an inelastic photon interaction are studied. The main radiation damage consists of ionizations of the atoms through the electron cascade following any inelastic photon interaction. Results of the method introduced in this investigation and results of an earlier theoretical studies of the influence of Auger-electron transport in diamond are in a good agreement. The dependence of the radiation damage as a function of the energy of the incident photon was studied by computer-aided simulations. The optimum energy range for diffraction experiments on the protein myoglobin is 10-40 keV. Studies of radiation damage as a function of crystal volume and shape revealed that very small plate or rod shaped crystals suffer less damage than crystals formed like a cube with the same volume. Furthermore the influence of a few heavy atoms in the protein molecule on radiation damage was examined. Already two iron atoms in the unit cell of myoglobin increase radiation damage significantly. (orig.)

Damage Model for Reliability Assessment of Solder Joints in Wind Turbines

DEFF Research Database (Denmark)

Kostandyan, Erik; Sørensen, John Dalsgaard

2012-01-01

environmental factors. Reliability assessment for such type of products conventionally is performed by classical reliability techniques based on test data. Usually conventional reliability approaches are time and resource consuming activities. Thus in this paper we choose a physics of failure approach to define...... damage model by Miner’s rule. Our attention is focused on crack propagation in solder joints of electrical components due to the temperature loadings. Based on the proposed method it is described how to find the damage level for a given temperature loading profile. The proposed method is discussed...

Global chromatin fibre compaction in response to DNA damage

International Nuclear Information System (INIS)

Hamilton, Charlotte; Hayward, Richard L.; Gilbert, Nick

2011-01-01

Highlights: ► Robust KAP1 phosphorylation in response to DNA damage in HCT116 cells. ► DNA repair foci are found in soluble chromatin. ► Biophysical analysis reveals global chromatin fibre compaction after DNA damage. ► DNA damage is accompanied by rapid linker histone dephosphorylation. -- Abstract: DNA is protected by packaging it into higher order chromatin fibres, but this can impede nuclear processes like DNA repair. Despite considerable research into the factors required for signalling and repairing DNA damage, it is unclear if there are concomitant changes in global chromatin fibre structure. In human cells DNA double strand break (DSB) formation triggers a signalling cascade resulting in H2AX phosphorylation (γH2AX), the rapid recruitment of chromatin associated proteins and the subsequent repair of damaged sites. KAP1 is a transcriptional corepressor and in HCT116 cells we found that after DSB formation by chemicals or ionising radiation there was a wave of, predominantly ATM dependent, KAP1 phosphorylation. Both KAP1 and phosphorylated KAP1 were readily extracted from cells indicating they do not have a structural role and γH2AX was extracted in soluble chromatin indicating that sites of damage are not attached to an underlying structural matrix. After DSB formation we did not find a concomitant change in the sensitivity of chromatin fibres to micrococcal nuclease digestion. Therefore to directly investigate higher order chromatin fibre structures we used a biophysical sedimentation technique based on sucrose gradient centrifugation to compare the conformation of chromatin fibres isolated from cells before and after DNA DSB formation. After damage we found global chromatin fibre compaction, accompanied by rapid linker histone dephosphorylation, consistent with fibres being more regularly folded or fibre deformation being stabilized by linker histones. We suggest that following DSB formation, although there is localised chromatin unfolding to

Mercury in Hair Is Inversely Related to Disease Associated Damage in Systemic Lupus Erythematosus

Directory of Open Access Journals (Sweden)

William Crowe

2015-12-01

Full Text Available Systemic lupus erythematosus (SLE is an autoimmune inflammatory disease, and environmental factors are proposed to exacerbate existing symptoms. One such environmental factor is mercury. The aim of this study was to investigate the relationship between exposure to mercury (Hg and disease activity and disease associated damage in Total Hg concentrations in hair and urine were measured in 52 SLE patients. Dental amalgams were quantified. Disease activity was assessed using three indexes including the British Isles Lupus Assessment Group Index (BILAG. Disease associated damage was measured using the Systemic Lupus International Collaborating Clinics/American College of Rheumatology SLICC/ACR Damage Index. Pearson’s correlation identified a significant negative correlation between hair Hg and BILAG (r = −0.323, p = 0.029 and SLICC/ACR (r = −0.377, p = 0.038. Multiple regression analysis identified hair Hg as a significant predictor of disease associated damage as determined by SLICC/ACR (β = −0.366, 95% confidence interval (CI: −1.769, −0.155 p = 0.019. Urinary Hg was not related to disease activity or damage. Fish consumption is the primary route of MeHg exposure in humans and the inverse association of hair Hg with disease activity observed here might be explained by the anti-inflammatory effects of n-3 long chain polyunsaturated fatty acids also found in fish.

Oxidative DNA damage and mammary cell proliferation by alcohol-derived salsolinol.

Science.gov (United States)

Murata, Mariko; Midorikawa, Kaoru; Kawanishi, Shosuke

2013-10-21

Drinking alcohol is a risk factor for breast cancer. Salsolinol (SAL) is endogenously formed by a condensation reaction of dopamine with acetaldehyde, a major ethanol metabolite, and SAL is detected in blood and urine after alcohol intake. We investigated the possibility that SAL can participate in tumor initiation and promotion by causing DNA damage and cell proliferation, leading to alcohol-associated mammary carcinogenesis. SAL caused oxidative DNA damage including 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), in the presence of transition metal ions, such as Cu(II) and Fe(III)EDTA. Inhibitory effects of scavengers on SAL-induced DNA damage and the electron spin resonance study indicated the involvement of H₂O₂, which is generated via the SAL radical. Experiments on scavengers and site specificity of DNA damage suggested ·OH generation via a Fenton reaction and copper-peroxide complexes in the presence of Fe(III)EDTA and Cu(II), respectively. SAL significantly increased 8-oxodG formation in normal mammary epithelial MCF-10A cells. In addition, SAL induced cell proliferation in estrogen receptor (ER)-negative MCF-10A cells, and the proliferation was inhibited by an antioxidant N-acetylcysteine and an epidermal growth factor receptor (EGFR) inhibitor AG1478, suggesting that reactive oxygen species may participate in the proliferation of MCF-10A cells via EGFR activation. Furthermore, SAL induced proliferation in estrogen-sensitive breast cancer MCF-7 cells, and a surface plasmon resonance sensor revealed that SAL significantly increased the binding activity of ERα to the estrogen response element but not ERβ. In conclusion, SAL-induced DNA damage and cell proliferation may play a role in tumor initiation and promotion of multistage mammary carcinogenesis in relation to drinking alcohol.

Neutron radiation damage studies in the structural materials of a 500 ...

Indian Academy of Sciences (India)

UTTIYOARNAB SAHA

2018-02-23

Feb 23, 2018 ... data library evaluated by the USA, ENDF/B-VII.1, wherein revisions were taken place in the new evaluations of basic nuclear data .... energy available for damage production after correct- ...... is a normalization factor such that.

Damage analysis. Product improvement through damage analysis; Schadensanalyse. Produktverbesserung durch Schadensanalyse

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

Within the 37th VDI annual meeting from 19th to 20th May, 2011 in Wuerzburg (Federal Republic of Germany) the following lectures and posters were presented: (1) Malpractice of material processing and heat processing of large gear wheels (P. Sommer); (2) Damages by faulty heat treatment - Case studies: Glow testing at a heat exchanger and wheel breakage of a high-strength screw connection (A. Thomas); (3) Crack formation in pole end plates of high-performance generators of a pumped-storage power plant - Causes and possibilities of remedy (J. Kinder); (4) Grind burn inspection for damage prevention at wind turbine gearboxes - Use of different processes for the investigation of peripheral-zone properties of case-hardened components (T. Griggel); (5) Damage inspection in coal mines using products from the degradation process as an example - damage - inspection - solution: This is the working method of the certification body (C. Kleine-Hegermann); (6) Damages at the sealing rings - Causes of the failure at radial shaft rings (K. Marchetti); (7) Thermal analyses at faulty plastic components (O. Jacobs); (8) Application of the micro computer tomography at damages of fibre-reinforced materials (H. Dinnebier); (9) The significance of 'material defects' from the view of lay people, lawyers and engineers - 'Material defect' in the literature, set of rules and expert opinion (C. Klinger); (10) Material defects from a legal view (P. Henseler); (11) Significance of material defects from the view of an engineering insurer (C. Harden); (12) Wear analyses by means of RNT and non-destructive surface analytics (K. Poehlmann); (13) Damages by means of non-metallic inclusions using ICE 3 as an example - Significance and localisation of single non-metallic inclusions in large components (D. Bettge); (14) Cathodic corrosion protection of pipeline steels (H.-G. Schoeneich); (15) Non-destructive and destructive investigations when assessing damages of corrosion at a

A novel damage index for damage identification using guided waves with application in laminated composites

International Nuclear Information System (INIS)

Torkamani, Shahab; Roy, Samit; Barkey, Mark E; Sazonov, Edward; Burkett, Susan; Kotru, Sushma

2014-01-01

In the current investigation, an innovative time-domain damage index is introduced for the first time which is based on local statistical features of the waveform. This damage index is called the ‘normalized correlation moment’ (NCM) and is composed of the nth moment of the cross-correlation of the baseline and comparison waves. The performance of this novel damage index is compared for some synthetic signals with that of an existing damage index based on the Pearson correlation coefficient (signal difference coefficient, SDC). The proposed damage index is shown to have significant advantages over the SDC, including sensitivity to the attenuation of the signal and lower sensitivity to the signal’s noise level. Numerical simulations using Abaqus finite element (FE) software show that this novel damage index is not only capable of detecting the delamination type of damage, but also exhibits a good ability in the assessment of this type of damage in laminated composite structures. The NCM damage index is also validated using experimental data for identification of delamination in composites. (paper)

DNA damage repair and radiosensitivity

International Nuclear Information System (INIS)

Suzuki, Norio

2003-01-01

Tailored treatment is not new in radiotherapy; it has been the major subject for the last 20-30 years. Radiation responses and RBE (relative biological effectiveness) depend on assay systems, endpoints, type of tissues and tumors, radiation quality, dose rate, dose fractionation, physiological and environmental factors etc, Latent times to develop damages also differ among tissues and endpoints depending on doses and radiation quality. Recent progress in clarification of radiation induced cell death, especially of apoptotic cell death, is quite important for understanding radiosensitivity of tumor cure process as well as of tumorigenesis. Apoptotic cell death as well as dormant cells had been unaccounted and missed into a part of reproductive cell death. Another area of major progress has been made in clarifying repair mechanisms of radiation damage, i.e., non-homologous end joining (NHEJ) and homologous recombinational repair (HRR). New approaches and developments such as cDNA or protein micro arrays and so called informatics in addition to basic molecular biological analysis are expected to aid identifying molecules and their roles in signal transduction pathways, which are multi-factorial and interactive each other being involved in radiation responses. (authors)

Damage to historic brick masonry structures. Masonry damage diagnostic system and damage atlas for evaluation of deterioration

NARCIS (Netherlands)

Balen, K. van; Binda, L.; Hees, R.P.J. van; Franke, L.

1996-01-01

The aim of the research on brick masonry degradation supported by the D.G. XII is presented. The project is delivering the following: ► Damage Atlas of ancient brick masonry, a book with a description of the types of damage, and their possible causes, in ancient brick masonry structures; ► Masonry

The role of tumor necrosis factor-α-related apoptosis-inducing ligand (TRAIL) in mediating autophagy in myositis skeletal muscle: A potential non-immune mechanism of muscle damage

Science.gov (United States)

Alger, Heather M.; Raben, Nina; Pistilli, Emidio; Francia, Dwight; Rawat, Rashmi; Getnet, Derese; Ghimbovschi, Svetlana; Chen, Yi-Wen; Lundberg, Ingrid E.; Nagaraju, Kanneboyina

2011-01-01

Objective Multinucleated cells are relatively resistant to classical apoptosis, and the factors initiating cell-death and damage in myositis are not well defined. We hypothesized that non-immune autophagic cell death may play a role in muscle fiber damage. Recent literature indicates that tumor necrosis factor-alpha-related apoptosis inducing ligand (TRAIL) may induce both NFκB (nuclear factor kappa-light chain enhancer of activated B cells) activation and autophagic cell death in other systems. Here, we have investigated its role in cell death and pathogenesis in vitro and in vivo using myositis (human and mouse) muscle tissues. Methods Gene expression profiling indicated that expression of TRAIL and several autophagy markers was specifically upregulated in myositis muscle tissue; these results were confirmed by immunohistochemistry and immunoblotting. We also analyzed TRAIL-induced cell death (apoptosis and autophagy) and NFκB activation in vitro in cultured cells. Results TRAIL was expressed predominantly in muscle fibers of myositis, but not in biopsies from normal or other dystrophic-diseased muscle. Autophagy markers were upregulated in human and mouse models of myositis. TRAIL expression was restricted to regenerating/atrophic areas of muscle fascicles, blood vessels, and infiltrating lymphocytes. TRAIL induced NFκB activation and IκB degradation in cultured cells that are resistant to TRAIL-induced apoptosis but undergo autophagic cell death. Conclusion Our data demonstrate that TRAIL is expressed in myositis muscle and may mediate both activation of NFκB and autophagic cell death in myositis. Thus, this non-immune pathway may be an attractive target for therapeutic intervention in myositis. PMID:21769834

Post-processing of fused silica and its effects on damage resistance to nanosecond pulsed UV lasers.

Science.gov (United States)

Ye, Hui; Li, Yaguo; Zhang, Qinghua; Wang, Wei; Yuan, Zhigang; Wang, Jian; Xu, Qiao

2016-04-10

HF-based (hydrofluoric acid) chemical etching has been a widely accepted technique to improve the laser damage performance of fused silica optics and ensure high-power UV laser systems at designed fluence. Etching processes such as acid concentration, composition, material removal amount, and etching state (etching with additional acoustic power or not) may have a great impact on the laser-induced damage threshold (LIDT) of treated sample surfaces. In order to find out the effects of these factors, we utilized the Taguchi method to determine the etching conditions that are helpful in raising the LIDT. Our results show that the most influential factors are concentration of etchants and the material etched away from the viewpoint of damage performance of fused silica optics. In addition, the additional acoustic power (∼0.6  W·cm-2) may not benefit the etching rate and damage performance of fused silica. Moreover, the post-cleaning procedure of etched samples is also important in damage performances of fused silica optics. Different post-cleaning procedures were, thus, experiments on samples treated under the same etching conditions. It is found that the "spraying + rinsing + spraying" cleaning process is favorable to the removal of etching-induced deposits. Residuals on the etched surface are harmful to surface roughness and optical transmission as well as laser damage performance.

Overexpression of the DNA mismatch repair factor, PMS2, confers hypermutability and DNA damage tolerance.

Science.gov (United States)

Gibson, Shannon L; Narayanan, Latha; Hegan, Denise Campisi; Buermeyer, Andrew B; Liskay, R Michael; Glazer, Peter M

2006-12-08

Inherited defects in genes associated with DNA mismatch repair (MMR) have been linked to familial colorectal cancer. Cells deficient in MMR are genetically unstable and demonstrate a tolerance phenotype in response to certain classes of DNA damage. Some sporadic human cancers also show abnormalities in MMR gene function, typically due to diminished expression of one of the MutL homologs, MLH1. Here, we report that overexpression of the MutL homolog, human PMS2, can also cause a disruption of the MMR pathway in mammalian cells, resulting in hypermutability and DNA damage tolerance. A mouse fibroblast cell line carrying a recoverable lambda phage shuttle vector for mutation detection was transfected with either a vector designed to express hPMS2 or with an empty vector control. Cells overexpressing hPMS2 were found to have elevated spontaneous mutation frequencies at the cII reporter gene locus. They also showed an increase in the level of mutations induced by the alkylating agent, methynitrosourea (MNU). Clonogenic survival assays demonstrated increased survival of the PMS2-overexpressing cells following exposure to MNU, consistent with the induction of a damage tolerance phenotype. Similar results were seen in cells expressing a mutant PMS2 gene, containing a premature stop codon at position 134 and representing a variant found in an individual with familial colon cancer. These results show that dysregulation of PMS2 gene expression can disrupt MMR function in mammalian cells and establish an additional carcinogenic mechanism by which cells can develop genetic instability and acquire resistance to cytotoxic cancer therapies.

A Coupled Plastic Damage Model for Concrete considering the Effect of Damage on Plastic Flow

OpenAIRE

Zhou, Feng; Cheng, Guangxu

2015-01-01

A coupled plastic damage model with two damage scalars is proposed to describe the nonlinear features of concrete. The constitutive formulations are developed by assuming that damage can be represented effectively in the material compliance tensor. Damage evolution law and plastic damage coupling are described using the framework of irreversible thermodynamics. The plasticity part is developed without using the effective stress concept. A plastic yield function based on the true stress is ado...

First wall material damage induced by fusion-fission neutron environment

Energy Technology Data Exchange (ETDEWEB)

Khripunov, Vladimir, E-mail: Khripunov_VI@nrcki.ru

2016-11-01

Highlights: • The highest damage and gas production rates are experienced within the first wall materials of a hybrid fusion-fission system. • About ∼2 times higher dpa and 4–5 higher He appm are expected compared to the values distinctive for a pure fusion system at the same DT-neutron wall loading. • The specific nuclear heating may be increased by a factor of ∼8–9 due to fusion and fission neutrons radiation capture in metal components of the first wall. - Abstract: Neutronic performance and inventory analyses were conducted to quantify the damage and gas production rates in candidate materials when used in a fusion-fission hybrid system first wall (FW). The structural materials considered are austenitic SS, Cu-alloy and V- alloys. Plasma facing materials included Be, and CFC composite and W. It is shown that the highest damage rates and gas particles production in materials are experienced within the FW region of a hybrid similar to a pure fusion system. They are greatly influenced by a combined neutron energy spectrum formed by the two-component fusion-fission neutron source in front of the FW and in a subcritical fission blanket behind. These characteristics are non-linear functions of the fission neutron source intensity. Atomic displacement damage production rate in the FW materials of a subcritical system (at the safe subcriticality limit of ∼0.95 and the neutron multiplication factor of ∼20) is almost ∼2 times higher compared to the values distinctive for a pure fusion system at the same 14 MeV neutron FW loading. Both hydrogen (H) and helium (He) gas production rates are practically on the same level except of about ∼4–5 times higher He-production in austenitic and reduced activation ferritic martensitic steels. A proper simulation of the damage environment in hybrid systems is required to evaluate the expected material performance and the structural component residence times.

Evaluation of new multiaxial damage parameters on low carbon steel

Directory of Open Access Journals (Sweden)

A. S. Cruces

2017-07-01

Full Text Available Most mechanical components are subjected to the complex fatigue loading conditions, where both amplitude and direction of loading cycles change over the time. The estimation of damage caused by these complex loading scenarios are often done by simplified uniaxial fatigue theories, which ultimately leads to higher factor of safety during the final design considerations. Critical plane-based fatigue theories have been considered more accurate for computing the fatigue damage for multiaxial loading conditions in comparison to energy-based and equivalent stress-based theories. Two recently developed fatigue theories have been evaluated in this work for the available test data. Test data includes significant amount of biaxial load paths.

Micromechanics-Based Damage Analysis of Fracture in Ti5553 Alloy with Application to Bolted Sectors

OpenAIRE

Ben Bettaieb, Mohamed; Van Hoof, Thibaut; Minnebo, Hans; Pardoen, Thomas; Dufour, Philippe; Jacques, Pascal; Habraken, Anne-Marie

2015-01-01

A physics-based, uncoupled damage model is calibrated using cylindrical notched round tensile specimens made of Ti5553 and Ti-6Al-4V alloys. The fracture strain of Ti5553 is lower than for Ti-6Al-4V in the full range of stress triaxiality. This lower ductility originates from a higher volume fraction of damage sites. By proper heat treatment, the fracture strain of Ti5553 increases by almost a factor of two, as a result of a larger damage nucleation stress. This result proves the potential fo...

Atherosclerotic vessel damage in systemic lupus erythematosus and antiphospholipid syndrome in men

Directory of Open Access Journals (Sweden)

A. I. Iljina

2005-01-01

Full Text Available Objective. To study prevalence of clinical and subclinical atherosclerosis signs in men with systemic lupus erythematosus (SLE and antiphospholipid syndrome, to assess relationship between atherosclerotic vessel damage, risk factors, CRP and anti-cardiolipin antibodies (АСА Material and methods. 62 pts were included. Mean age was 35,7+11,6 years, mean disease duration - 129,3± 102 months. Traditional and related to the disease risk factors were analyzed. To reveal atherosclerotic vessel damage carotid sonographic examination was performed. Serum CRP concentration was evaluated by high sensitivity nephelometric immunoassay. IgG and IgM АСА were assessed by solid-phase immuno-enzyme assay. Results. Sonographic signs of carotid damage was revealed in 58% of pts, clinical signs of atherosclerosis - in 42%. Pts were divided into two groups according to intima-media complex thickness (IMCT. Group I included 36 pts with atherosclerotic vessel damage signs (IMCT?0,9 mm. Group 2-26 pts with IMCT<0,9 mm. Mean age at the examination, age of disease onset, disease duration, smoking frequency damage index in group I pts were higher than in group 2 pts. Mean CRP concentration in atherosclerosis group was significantly higher than in group 2 (p=0,007. 19 pts had APS signs. 43 pts did not. CRP level significantly correlated with IMCT in SLE pts with and without APS (p<0,05. Pts with atherosclerosis had higher IgG АСА level though the differences were not statistically significant. Conclusion. Men with SLE with or without APS have high risk of atherosclerosis development. CRP elevation is associated with IMCT increase.

Damage pattern and damage progression on breakwater roundheads under multidirectional waves

DEFF Research Database (Denmark)

Comola, F.; Andersen, Thomas Lykke; Martinelli, L.

2014-01-01

An experimental model test study is carried out to investigate damage pattern and progression on a rock armoured breakwater roundhead subjected to multidirectional waves. Concerning damage pattern, the most critical sector is observed to shift leeward with increasing wave period. Taking angles...... over the roundhead is developed. Thus the formula also considers the shifting of the critical sector due to increasing wave period which existing formulae do not include. Finally, analysing the damage produced by double peaked spectra, it is shown that the armour may be designed by the formula when...

Bayesian inference method for stochastic damage accumulation modeling

International Nuclear Information System (INIS)

Jiang, Xiaomo; Yuan, Yong; Liu, Xian

2013-01-01

Damage accumulation based reliability model plays an increasingly important role in successful realization of condition based maintenance for complicated engineering systems. This paper developed a Bayesian framework to establish stochastic damage accumulation model from historical inspection data, considering data uncertainty. Proportional hazards modeling technique is developed to model the nonlinear effect of multiple influencing factors on system reliability. Different from other hazard modeling techniques such as normal linear regression model, the approach does not require any distribution assumption for the hazard model, and can be applied for a wide variety of distribution models. A Bayesian network is created to represent the nonlinear proportional hazards models and to estimate model parameters by Bayesian inference with Markov Chain Monte Carlo simulation. Both qualitative and quantitative approaches are developed to assess the validity of the established damage accumulation model. Anderson–Darling goodness-of-fit test is employed to perform the normality test, and Box–Cox transformation approach is utilized to convert the non-normality data into normal distribution for hypothesis testing in quantitative model validation. The methodology is illustrated with the seepage data collected from real-world subway tunnels.

Inelastic damage using continuum damage mechanics in composite plate reinforced by unidirectional fibers

Directory of Open Access Journals (Sweden)

Žmindák Milan

2018-01-01

Full Text Available It is well that a finite element method is very popular simulation method to predict the physical behavior of systems and structures. In the last years an increase of interest in a new type of numerical methods known as meshless methods was observed. The paper deals with application of radial basis functions on modelling of inelastic damage using continuum damage mechanics of layered plate composite structures reinforced with long unidirectional fibers. For numerical simulations of elastic-plastic damage of layered composite plates own computational programs were implemented in MATLAB programming language. We will use the Newton-Raphson method to solve nonlinear systems of equations. Evaluation damage during plasticity has been solved using return mapping algorithm. The results of elastic-plastic damage analysis of composite plate with unsymmetrical laminate stacking sequence are presented.

Earthquake damage to underground facilities

International Nuclear Information System (INIS)

Pratt, H.R.; Hustrulid, W.A.; Stephenson, D.E.

1978-11-01

The potential seismic risk for an underground nuclear waste repository will be one of the considerations in evaluating its ultimate location. However, the risk to subsurface facilities cannot be judged by applying intensity ratings derived from the surface effects of an earthquake. A literature review and analysis were performed to document the damage and non-damage due to earthquakes to underground facilities. Damage from earthquakes to tunnels, s, and wells and damage (rock bursts) from mining operations were investigated. Damage from documented nuclear events was also included in the study where applicable. There are very few data on damage in the subsurface due to earthquakes. This fact itself attests to the lessened effect of earthquakes in the subsurface because mines exist in areas where strong earthquakes have done extensive surface damage. More damage is reported in shallow tunnels near the surface than in deep mines. In mines and tunnels, large displacements occur primarily along pre-existing faults and fractures or at the surface entrance to these facilities.Data indicate vertical structures such as wells and shafts are less susceptible to damage than surface facilities. More analysis is required before seismic criteria can be formulated for the siting of a nuclear waste repository

Ultraviolet radiation, sun damage and preventing

International Nuclear Information System (INIS)

Johnsen, B.; Christensen, T.; Nilsen, L.T.; Hannevik, M.

2013-01-01

The report focuses on the large impact of health damages due to excessive UV exposure from natural sun. The first part of the report gives background information on factors significantly affecting the intensity of UV radiation. The second part gives an overview of health effects related to UV exposure, with recommendations on how to avoid excessive UV exposure and still enjoy the positive sides of outdoor activity. The report is intended to contribute to informational activities about sun exposure as recommended by the World Health Organisation and the World Meteorology Organisation. (Author)

Structural Health Monitoring for Impact Damage in Composite Structures.

Energy Technology Data Exchange (ETDEWEB)

Roach, Dennis P.; Raymond Bond (Purdue); Doug Adams (Purdue)

2014-08-01

Composite structures are increasing in prevalence throughout the aerospace, wind, defense, and transportation industries, but the many advantages of these materials come with unique challenges, particularly in inspecting and repairing these structures. Because composites of- ten undergo sub-surface damage mechanisms which compromise the structure without a clear visual indication, inspection of these components is critical to safely deploying composite re- placements to traditionally metallic structures. Impact damage to composites presents one of the most signi fi cant challenges because the area which is vulnerable to impact damage is generally large and sometimes very dif fi cult to access. This work seeks to further evolve iden- ti fi cation technology by developing a system which can detect the impact load location and magnitude in real time, while giving an assessment of the con fi dence in that estimate. Fur- thermore, we identify ways by which impact damage could be more effectively identi fi ed by leveraging impact load identi fi cation information to better characterize damage. The impact load identi fi cation algorithm was applied to a commercial scale wind turbine blade, and results show the capability to detect impact magnitude and location using a single accelerometer, re- gardless of sensor location. A technique for better evaluating the uncertainty of the impact estimates was developed by quantifying how well the impact force estimate meets the assump- tions underlying the force estimation technique. This uncertainty quanti fi cation technique was found to reduce the 95% con fi dence interval by more than a factor of two for impact force estimates showing the least uncertainty, and widening the 95% con fi dence interval by a fac- tor of two for the most uncertain force estimates, avoiding the possibility of understating the uncertainty associated with these estimates. Linear vibration based damage detection tech- niques were investigated in the

Cell damage evaluation of mammalian cells in cell manipulation by amplified femtosecond ytterbium laser

Science.gov (United States)

Hong, Z.-Y.; Iino, T.; Hagihara, H.; Maeno, T.; Okano, K.; Yasukuni, R.; Hosokawa, Y.

2018-03-01

A micrometer-scale explosion with cavitation bubble generation is induced by focusing a femtosecond laser in an aqueous solution. We have proposed to apply the explosion as an impulsive force to manipulate mammalian cells especially in microfluidic chip. Herein, we employed an amplified femtosecond ytterbium laser as an excitation source for the explosion and evaluated cell damage in the manipulation process to clarify the application potential. The damage of C2C12 myoblast cell prepared as a representative mammalian cell was investigated as a function of distance between cell and laser focal point. Although the cell received strong damage on the direct laser irradiation condition, the damage sharply decreased with increasing distance. Since the threshold distance, above which the cell had no damage, was consistent with radius of the cavitation bubble, impact of the cavitation bubble would be a critical factor for the cell damage. The damage had strong nonlinearity in the pulse energy dependence. On the other hand, cell position shift by the impact of the cavitation bubble was almost proportional to the pulse energy. In balance between the cell viability and the cell position shift, we elucidated controllability of the cell manipulation in microfluidic chip.

Interaction of elementary damage processes and their contribution to neutron damage of ceramics

International Nuclear Information System (INIS)

Itoh, Noriaki

1989-01-01

Specific features of radiation damage of ceramics as compared with those of metals are discussed. It is pointed out that the electronic excitation gives considerable contribution to radiation damage of ceramics not only by itself but also through interaction with knock-on processes. In the talk first I mention briefly the elementary damage processes; the knock-on process and the processes induced by electronic excitation; the latter is of particularly importance in ceramics because of large energy quantums. Then I discuss possible interactions between these elementary processes; why they may contribute to radiation damage and in what situation they are induced. The types of interactions discussed include those between knock-on processes, between electronic excitation and knock-on processes and between processes induced by electronic excitation. Experimental results which prove directly the significance of such interactions are also described. Importance of such interactions in radiation damage of ceramics and their relevance to other phenomena, such as laser damage, is emphasized. Possible experimental techniques, including those which uses high energy neutron sources, are described. (author)

Fukunaga-Koontz feature transformation for statistical structural damage detection and hierarchical neuro-fuzzy damage localisation

Science.gov (United States)

Hoell, Simon; Omenzetter, Piotr

2017-07-01

Considering jointly damage sensitive features (DSFs) of signals recorded by multiple sensors, applying advanced transformations to these DSFs and assessing systematically their contribution to damage detectability and localisation can significantly enhance the performance of structural health monitoring systems. This philosophy is explored here for partial autocorrelation coefficients (PACCs) of acceleration responses. They are interrogated with the help of the linear discriminant analysis based on the Fukunaga-Koontz transformation using datasets of the healthy and selected reference damage states. Then, a simple but efficient fast forward selection procedure is applied to rank the DSF components with respect to statistical distance measures specialised for either damage detection or localisation. For the damage detection task, the optimal feature subsets are identified based on the statistical hypothesis testing. For damage localisation, a hierarchical neuro-fuzzy tool is developed that uses the DSF ranking to establish its own optimal architecture. The proposed approaches are evaluated experimentally on data from non-destructively simulated damage in a laboratory scale wind turbine blade. The results support our claim of being able to enhance damage detectability and localisation performance by transforming and optimally selecting DSFs. It is demonstrated that the optimally selected PACCs from multiple sensors or their Fukunaga-Koontz transformed versions can not only improve the detectability of damage via statistical hypothesis testing but also increase the accuracy of damage localisation when used as inputs into a hierarchical neuro-fuzzy network. Furthermore, the computational effort of employing these advanced soft computing models for damage localisation can be significantly reduced by using transformed DSFs.

Ozone damage to tobacco in Canada

Energy Technology Data Exchange (ETDEWEB)

Macdowall, F D.H.; Vickery, L S; Runeckles, V C; Patrick, Z A

1963-12-01

Tobacco weather fleck has caused significant losses of flue-cured tobacco in southern Ontario since 1955. Fleck damage was greatest near the coast of Lake Erie and decreased progressively inland. Ozone has been shown to be one of the most important incitants of the fleck response in tobacco whereas parasitic fungi, bacteria and viruses were proven not to be implicated as causes of the disorder. The inherently susceptible variety White Gold, used in all tests, was rendered more susceptible by irrigation and nitrogen deficiency. It was also more susceptible during flowering and when producing lateral shoots. The degree and duration of stomatal opening were important factors in determining the amount of injury. Concentration of ozone in the air was shown experimentally to affect the speed of fleck response as well as the severity of symptoms. Statistically significant correlations between ozone concentrations and fleck damage were obtained from field data when the response of highly susceptible tissues only was considered. The merits of several visual rating methods are compared and discussed. 22 references, 5 figures, 11 tables.

Shock Initiation of Damaged Explosives

Energy Technology Data Exchange (ETDEWEB)

Chidester, S K; Vandersall, K S; Tarver, C M

2009-10-22

Explosive and propellant charges are subjected to various mechanical and thermal insults that can increase their sensitivity over the course of their lifetimes. To quantify this effect, shock initiation experiments were performed on mechanically and thermally damaged LX-04 (85% HMX, 15% Viton by weight) and PBX 9502 (95% TATB, 5% Kel-F by weight) to obtain in-situ manganin pressure gauge data and run distances to detonation at various shock pressures. We report the behavior of the HMX-based explosive LX-04 that was damaged mechanically by applying a compressive load of 600 psi for 20,000 cycles, thus creating many small narrow cracks, or by cutting wedge shaped parts that were then loosely reassembled, thus creating a few large cracks. The thermally damaged LX-04 charges were heated to 190 C for long enough for the beta to delta solid - solid phase transition to occur, and then cooled to ambient temperature. Mechanically damaged LX-04 exhibited only slightly increased shock sensitivity, while thermally damaged LX-04 was much more shock sensitive. Similarly, the insensitive explosive PBX 9502 was mechanically damaged using the same two techniques. Since PBX 9502 does not undergo a solid - solid phase transition but does undergo irreversible or 'rachet' growth when thermally cycled, thermal damage to PBX 9502 was induced by this procedure. As for LX-04, the thermally damaged PBX 9502 demonstrated a greater shock sensitivity than mechanically damaged PBX 9502. The Ignition and Growth reactive flow model calculated the increased sensitivities by igniting more damaged LX-04 and PBX 9502 near the shock front based on the measured densities (porosities) of the damaged charges.

Repair rather than segregation of damage is the optimal unicellular aging strategy.

Science.gov (United States)

Clegg, Robert J; Dyson, Rosemary J; Kreft, Jan-Ulrich

2014-08-16

How aging, being unfavourable for the individual, can evolve is one of the fundamental problems of biology. Evidence for aging in unicellular organisms is far from conclusive. Some studies found aging even in symmetrically dividing unicellular species; others did not find aging in the same, or in different, unicellular species, or only under stress. Mathematical models suggested that segregation of non-genetic damage, as an aging strategy, would increase fitness. However, these models failed to consider repair as an alternative strategy or did not properly account for the benefits of repair. We used a new and improved individual-based model to examine rigorously the effect of a range of aging strategies on fitness in various environments. Repair of damage emerges as the best strategy despite its fitness costs, since it immediately increases growth rate. There is an optimal investment in repair that outperforms damage segregation in well-mixed, lasting and benign environments over a wide range of parameter values. Damage segregation becomes beneficial, and only in combination with repair, when three factors are combined: (i) the rate of damage accumulation is high, (ii) damage is toxic and (iii) efficiency of repair is low. In contrast to previous models, our model predicts that unicellular organisms should have active mechanisms to repair damage rather than age by segregating damage. Indeed, as predicted, all organisms have evolved active mechanisms of repair whilst aging in unicellular organisms is absent or minimal under benign conditions, apart from microorganisms with a different ecology, inhabiting short-lived environments strongly favouring early reproduction rather than longevity. Aging confers no fitness advantage for unicellular organisms in lasting environments under benign conditions, since repair of non-genetic damage is better than damage segregation.

Cellular Response to Bleomycin-Induced DNA Damage in Human Fibroblast Cells in Space

Science.gov (United States)

Lu, Tao; Zhang, Ye; Wong, Michael; Stodieck, Louis; Karouia, Fathi; Wu, Honglu

2015-01-01

Outside the protection of the geomagnetic field, astronauts and other living organisms are constantly exposed to space radiation that consists of energetic protons and other heavier charged particles. Whether spaceflight factors, microgravity in particular, have effects on cellular responses to DNA damage induced by exposure to radiation or cytotoxic chemicals is still unknown, as is their impact on the radiation risks for astronauts and on the mutation rate in microorganisms. Although possible synergistic effects of space radiation and other spaceflight factors have been investigated since the early days of the human space program, the published results were mostly conflicting and inconsistent. To investigate effects of spaceflight on cellular responses to DNA damages, human fibroblast cells flown to the International Space Station (ISS) were treated with bleomycin for three hours in the true microgravity environment, which induced DNA damages including double-strand breaks (DSB) similar to the ionizing radiation. Damages in the DNA were measured by the phosphorylation of a histone protein H2AX (g-H2AX), which showed slightly more foci in the cells on ISS than in the ground control. The expression of genes involved in DNA damage response was also analyzed using the PCR array. Although a number of the genes, including CDKN1A and PCNA, were significantly altered in the cells after bleomycin treatment, no significant difference in the expression profile of DNA damage response genes was found between the flight and ground samples. At the time of the bleomycin treatment, the cells on the ISS were found to be proliferating faster than the ground control as measured by the percentage of cells containing positive Ki-67 signals. Our results suggested that the difference in g-H2AX focus counts between flight and ground was due to the faster growth rate of the cells in space, but spaceflight did not affect initial transcriptional responses of the DNA damage response genes to

Radiation damage by high-energy electrons in GaAs: DLTS investigation

International Nuclear Information System (INIS)

Lehmann, B.

1991-10-01

An isothermal variation of the DLTS technique is developed and applied to the study of displacement damage in GaAs, through the determination of threshold energies and displacement cross sections. Its results correspond to those of an LED based method. A pronounced anisotropy is found for the threshold energy. A linearly increasing displacement probability function is shown to properly model the displacement cross section in direction, as compared with the direction which requires only a single step function. Differences in the damage between these two directions are as large as a factor of two. (orig.) [de

Damage Analysis and Evaluation of High Strength Concrete Frame Based on Deformation-Energy Damage Model

Directory of Open Access Journals (Sweden)

Huang-bin Lin

2015-01-01

Full Text Available A new method of characterizing the damage of high strength concrete structures is presented, which is based on the deformation energy double parameters damage model and incorporates both of the main forms of damage by earthquakes: first time damage beyond destruction and energy consumption. Firstly, test data of high strength reinforced concrete (RC columns were evaluated. Then, the relationship between stiffness degradation, strength degradation, and ductility performance was obtained. And an expression for damage in terms of model parameters was determined, as well as the critical input data for the restoring force model to be used in analytical damage evaluation. Experimentally, the unloading stiffness was found to be related to the cycle number. Then, a correction for this changing was applied to better describe the unloading phenomenon and compensate for the shortcomings of structure elastic-plastic time history analysis. The above algorithm was embedded into an IDARC program. Finally, a case study of high strength RC multistory frames was presented. Under various seismic wave inputs, the structural damages were predicted. The damage model and correction algorithm of stiffness unloading were proved to be suitable and applicable in engineering design and damage evaluation of a high strength concrete structure.

Radiation damage in silicon exposed to high-energy protons

International Nuclear Information System (INIS)

Davies, Gordon; Hayama, Shusaku; Murin, Leonid; Krause-Rehberg, Reinhard; Bondarenko, Vladimir; Sengupta, Asmita; Davia, Cinzia; Karpenko, Anna

2006-01-01

Photoluminescence, infrared absorption, positron annihilation, and deep-level transient spectroscopy (DLTS) have been used to investigate the radiation damage produced by 24 GeV/c protons in crystalline silicon. The irradiation doses and the concentrations of carbon and oxygen in the samples have been chosen to monitor the mobility of the damage products. Single vacancies (and self-interstitials) are introduced at the rate of ∼1 cm -1 , and divacancies at 0.5 cm -1 . Stable di-interstitials are formed when two self-interstitials are displaced in one damage event, and they are mobile at room temperature. In the initial stages of annealing the evolution of the point defects can be understood mainly in terms of trapping at the impurities. However, the positron signal shows that about two orders of magnitude more vacancies are produced by the protons than are detected in the point defects. Damage clusters exist, and are largely removed by annealing at 700 to 800 K, when there is an associated loss of broad band emission between 850 and 1000 meV. The well-known W center is generated by restructuring within clusters, with a range of activation energies of about 1.3 to 1.6 eV, reflecting the disordered nature of the clusters. Comparison of the formation of the X centers in oxygenated and oxygen-lean samples suggests that the J defect may be interstitial related rather than vacancy related. To a large extent, the damage and annealing behavior may be factorized into point defects (monitored by sharp-line optical spectra and DLTS) and cluster defects (monitored by positron annihilation and broadband luminescence). Taking this view to the limit, the generation rates for the point defects are as predicted by simply taking the damage generated by the Coulomb interaction of the protons and Si nuclei

Radiation damage

CERN Document Server

Heijne, Erik H M; CERN. Geneva

1998-01-01

a) Radiation damage in organic materials. This series of lectures will give an overview of radiation effects on materials and components frequently used in accelerator engineering and experiments. Basic degradation phenomena will be presented for organic materials with comprehensive damage threshold doses for commonly used rubbers, thermoplastics, thermosets and composite materials. Some indications will be given for glass, scintillators and optical fibres. b) Radiation effects in semiconductor materials and devices. The major part of the time will be devoted to treat radiation effects in semiconductor sensors and the associated electronics, in particular displacement damage, interface and single event phenomena. Evaluation methods and practical aspects will be shown. Strategies will be developed for the survival of the materials under the expected environmental conditions of the LHC machine and detectors. I will describe profound revolution in our understanding of black holes and their relation to quantum me...

Study of lixiviant damage of a sandstone deposit during in-situ leaching of uranium

International Nuclear Information System (INIS)

Liao Wensheng; Wang Limin; Jiang Yan; Jiang Guoping; Tan Yahui

2014-01-01

The permeability of sandstone deposit is a key factor for economical uranium recovery during in-situ leaching uranium. Low permeability sandstone uranium deposits behave low push-pull capacity, and show formation damage in leaching operations. It is important to study formation damage of permeability, therefore, and to stabilize even improve the push-pull power of drillholes during in-situ leaching. In this paper, formation damage caused by lixiviants was investigated based on a low permeability sandstone uranium deposit. The resulted showed that, under the conditions of in-situ leaching, the salinity of leaching fluid has no harm to formation permeability, on the contrary, the increment of salinity of lixiviant during in-situ leaching improve the permeability of the deposit. The alkalinity, hydrogen peroxide and productivity of the lixiviant cause no significant formation damage. But the fine particles in the lixiviant shows formation damage significantly, and the quantity of the particles should be controlled during production. (authors)

Hydro-Economic based Model of Damage and Loss Analysis of Winongo River Flood

Directory of Open Access Journals (Sweden)

Muhammad Rifki Hardika

2017-09-01

Full Text Available Winongo River experienced considerably high flow that caused overflows along the downstream part of the river and some inundation at the surrounding area. The inundation has reached up to 1 m spread over the Tegalrejo Sub-district of Yogyakarta City and swept two houses. This paper analyses the damage and loss due to the flood by taking into account the hydraulics phenomena and the economic impact at the inundation area. A hydraulics model has been developed to study the flow characteristics during the flood of Winongo River, especially in the river reach in Tegalrejo Sub-district. The hazard-induced damages in the flooded area were identified and the economic impacts were studied. Several related software have been utilized to analyse the damage and loss of the disaster, including the HEC-RAS 5.0, ArcGIS, HEC-GeoRAS and InaSAFE. Through the integration of the characteristics of both flood phenomena and the economic factor, the damage and loss were then analysed and the Average Annual Damage (AAD of approximately IDR 88,750,000,000 was obtained.

ATM-activated autotaxin (ATX) propagates inflammation and DNA damage in lung epithelial cells: a new mode of action for silica-induced DNA damage?

Science.gov (United States)

Zheng, Huiyuan; Högberg, Johan; Stenius, Ulla

2017-12-07

Silica exposure is a common risk factor for lung cancer. It has been claimed that key elements in cancer development are activation of inflammatory cells that indirectly induce DNA damage and proliferative stimuli in respiratory epithelial cells. We studied DNA damage induced by silica particles in respiratory epithelial cells and focused the role of the signaling enzyme autotaxin (ATX). A549 and 16 bronchial epithelial cells (16HBE) lung epithelial cells were exposed to silica particles. Reactive oxygen species (ROS), NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasome activation, ATX, ataxia telangiectasia mutated (ATM), and DNA damage (γH2AX, pCHK1, pCHK2, comet assay) were end points. Low doses of silica induced NLRP3 activation, DNA damage accumulation, and ATM phosphorylation. A novel finding was that ATM induced ATX generation and secretion. Not only silica but also rotenone, camptothecin and H2O2 activated ATX via ATM, suggesting that ATX is part of a generalized ATM response to double-strand breaks (DSBs). Surprisingly, ATX inhibition mitigated DNA damage accumulation at later time points (6-16 h), and ATX transfection caused NLRP3 activation and DNA damage. Furthermore, the product of ATX enzymatic activity, lysophosphatidic acid, recapitulated the effects of ATX transfection. These data indicate an ATM-ATX-dependent loop that propagates inflammation and DSB accumulation, making low doses of silica effective inducers of DSBs in epithelial cells. We conclude that an ATM-ATX axis interconnects DSBs with silica-induced inflammation and propagates these effects in epithelial cells. Further studies of this adverse outcome pathway may give an accurate assessment of the lowest doses of silica that causes cancer. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Thermomechanics of damageable materials under diffusion: modelling and analysis

Czech Academy of Sciences Publication Activity Database

Roubíček, Tomáš; Tomassetti, G.

2015-01-01

Roč. 66, č. 6 (2015), s. 3535-3572 ISSN 0044-2275 R&D Projects: GA ČR GAP201/10/0357 Institutional support: RVO:61388998 Keywords : visco-elastic porous solids * incomplete damage * diffusion driven by chemical-potential gradient Subject RIV: BA - General Mathematics Impact factor: 1.560, year: 2015 http://link.springer.com/article/10.1007/s00033-015-0566-2

Proton-induced direct and indirect damage of plasmid DNA

Czech Academy of Sciences Publication Activity Database

Vyšín, Luděk; Pachnerová Brabcová, Kateřina; Štěpán, V.; Moretto-Capelle, P.; Bugler, B.; Legube, G.; Cafarelli, P.; Casta, R.; Champeaux, J. P.; Sence, M.; Vlk, M.; Wagner, Richard; Štursa, Jan; Zach, Václav; Incerti, S.; Juha, Libor; Davídková, Marie

2015-01-01

Roč. 54, č. 3 (2015), s. 343-352 ISSN 0301-634X R&D Projects: GA ČR GA13-28721S; GA MŠk LD12008; GA MŠk LM2011019 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : proton radiation * DNA plasmid * direct and indirect effects * clustered damage * repair enzymes Subject RIV: BO - Biophysics Impact factor: 1.923, year: 2015

Thermomechanical fatigue and damage mechanisms in Sanicro 25 steel

Czech Academy of Sciences Publication Activity Database

Petráš, Roman; Škorík, Viktor; Polák, Jaroslav

2016-01-01

Roč. 650, JAN (2016), s. 52-62 ISSN 0921-5093 R&D Projects: GA MŠk(CZ) EE2.3.30.0063; GA ČR(CZ) GA13-23652S Institutional support: RVO:68081723 Keywords : thermomechanical fatigue * Sanicro 25 steel * damage mechanism * FIB cutting * localized oxidation-cracking Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 3.094, year: 2016

DNA damage preceding dopamine neuron degeneration in A53T human α-synuclein transgenic mice

International Nuclear Information System (INIS)

Wang, Degui; Yu, Tianyu; Liu, Yongqiang; Yan, Jun; Guo, Yingli; Jing, Yuhong; Yang, Xuguang; Song, Yanfeng; Tian, Yingxia

2016-01-01

Defective DNA repair has been linked with age-associated neurodegenerative disorders. Parkinson's disease (PD) is a progressive neurodegenerative disorder caused by genetic and environmental factors. Whether damages to nuclear DNA contribute to neurodegeneration of PD still remain obscure. in this study we aim to explore whether nuclear DNA damage induce dopamine neuron degeneration in A53T human α-Synuclein over expressed mouse model. We investigated the effects of X-ray irradiation on A53T-α-Syn MEFs and A53T-α-Syn transgene mice. Our results indicate that A53T-α-Syn MEFs show a prolonged DNA damage repair process and senescense phenotype. DNA damage preceded onset of motor phenotype in A53T-α-Syn transgenic mice and decrease the number of nigrostriatal dopaminergic neurons. Neurons of A53T-α-Syn transgenic mice are more fragile to DNA damages. - Highlights: • This study explore contribution of DNA damage to neurodegeneration in Parkinson's disease mice. • A53T-α-Syn MEF cells show a prolonged DNA damage repair process and senescense phenotype. • DNA damage preceded onset of motor phenotype in A53T-α-Syn transgenic mice. • DNA damage decrease the number of nigrostriatal dopaminergic neurons. • Neurons of A53T-α-Syn transgenic mice are more fragile to DNA damages.

Thermal stress analysis for fatigue damage evaluation at a mixing tee

International Nuclear Information System (INIS)

Kamaya, Masayuki; Nakamura, Akira

2011-01-01

-dimensional simplified analysis could be used for evaluating the fatigue damage without adopting the stress enhancement factor K t quoted in the JSME guideline. The results also suggested that, for a precise assessment of the fatigue damage at a mixing tee, the effect of multi-axial stress on the fatigue life together with the mean stress effect should be taken into account.

Spatial Damage Distribution over Cube Armoured Roundheads

DEFF Research Database (Denmark)

Alonso, Enrique Maciñeira; Burcharth, Hans F.

2009-01-01

Different authors have studied and defined the most critical sector of the roundheads with respect to armour stability in order to calculate the mass needed in the units of the armour. This sector has been located between 90° and 135° relative to the orthogonal of the waves. Moreover, from...... provides data on damage distribution over the head obtained in 3D physical model tests with short crested waves at Aalborg University. Furthermore, the factors influencing the distributions are explained....

Nrf2 deficiency potentiates methamphetamine-induced dopaminergic axonal damage and gliosis in the striatum.

Science.gov (United States)

Granado, Noelia; Lastres-Becker, Isabel; Ares-Santos, Sara; Oliva, Idaira; Martin, Eduardo; Cuadrado, Antonio; Moratalla, Rosario

2011-12-01

Oxidative stress that correlates with damage to nigrostriatal dopaminergic neurons and reactive gliosis in the basal ganglia is a hallmark of methamphetamine (METH) toxicity. In this study, we analyzed the protective role of the transcription factor Nrf2 (nuclear factor-erythroid 2-related factor 2), a master regulator of redox homeostasis, in METH-induced neurotoxicity. We found that Nrf2 deficiency exacerbated METH-induced damage to dopamine neurons, shown by an increase in loss of tyrosine hydroxylase (TH)- and dopamine transporter (DAT)-containing fibers in striatum. Consistent with these effects, Nrf2 deficiency potentiated glial activation, indicated by increased striatal expression of markers for microglia (Mac-1 and Iba-1) and astroglia (GFAP) one day after METH administration. At the same time, Nrf2 inactivation dramatically potentiated the increase in TNFα mRNA and IL-15 protein expression in GFAP+ cells in the striatum. In sharp contrast to the potentiation of striatal damage, Nrf2 deficiency did not affect METH-induced dopaminergic neuron death or expression of glial markers or proinflammatory molecules in the substantia nigra. This study uncovers a new role for Nrf2 in protection against METH-induced inflammatory and oxidative stress and striatal degeneration. Copyright © 2011 Wiley‐Liss, Inc.

Delay-active damage versus non-local enhancement for anisotropic damage dynamics computations with alternated loading

International Nuclear Information System (INIS)

Desmorat, R.; Chambart, M.; Gatuingt, F.; Guilbaud, D.

2010-01-01

Anisotropic damage thermodynamics framework allows to model the concrete-like materials behavior and in particular their dissymmetric tension/compression response. To deal with dynamics applications such as impact, it is furthermore necessary to take into account the strain rate effect observed experimentally. This is done in the present work by means of anisotropic visco-damage, by introducing a material strain rate effect in the cases of positive hydrostatic stresses only. The proposed delay-damage law assumes no viscous effect in compression as the consideration of inertia effects proves sufficient to model the apparent material strength increase. High-rate dynamics applications imply to deal with wave propagation and reflection which can generate alternated loading in the impacted structure. In order to do so, the key concept of active damage is defined and introduced within both the damage criterion and the delay-damage evolution law. At the structural level, strain localization often leads to spurious mesh dependency. Three-dimensional Finite Element computations of dynamic tensile tests by spalling are presented, with visco-damage and either without or with non-local enhancement. Delay-damage, as introduced, regularizes the solution in fast dynamics. The location of the macro-crack initiated is found influenced by non-local regularization. The strain rate range in which each enhancement, delay-damage or non-local enhancement, has a regularizing effect is studied. (authors)

Assessment of compressive failure process of cortical bone materials using damage-based model.

Science.gov (United States)

Ng, Theng Pin; R Koloor, S S; Djuansjah, J R P; Abdul Kadir, M R

2017-02-01

The main failure factors of cortical bone are aging or osteoporosis, accident and high energy trauma or physiological activities. However, the mechanism of damage evolution coupled with yield criterion is considered as one of the unclear subjects in failure analysis of cortical bone materials. Therefore, this study attempts to assess the structural response and progressive failure process of cortical bone using a brittle damaged plasticity model. For this reason, several compressive tests are performed on cortical bone specimens made of bovine femur, in order to obtain the structural response and mechanical properties of the material. Complementary finite element (FE) model of the sample and test is prepared to simulate the elastic-to-damage behavior of the cortical bone using the brittle damaged plasticity model. The FE model is validated in a comparative method using the predicted and measured structural response as load-compressive displacement through simulation and experiment. FE results indicated that the compressive damage initiated and propagated at central region where maximum equivalent plastic strain is computed, which coincided with the degradation of structural compressive stiffness followed by a vast amount of strain energy dissipation. The parameter of compressive damage rate, which is a function dependent on damage parameter and the plastic strain is examined for different rates. Results show that considering a similar rate to the initial slope of the damage parameter in the experiment would give a better sense for prediction of compressive failure. Copyright © 2016 Elsevier Ltd. All rights reserved.

Beam damage of self-assembled monolayers

International Nuclear Information System (INIS)

Rieke, P.C.; Baer, D.R.; Fryxell, G.E.; Engelhard, M.H.; Porter, M.S.

1993-01-01

X-ray and electron beam damage studies were performed on Br-terminated and methyl-terminated alkylsilane self-assembled monolayers. X-ray beam initiated damage was primarily limited to removal of the labile Br group and did not significantly damage the hydrocarbon chain. Some of the x-ray beam damage could be attributed to low-energy electrons emitted by the non-monochromatic source, but further damage was attributed to secondary electrons produced in the sample by x-ray exposure. Electron beams caused significant damage to the hydrocarbon chains. Maximum damage occurred with a beam energy of 600 eV and a dosage of 6x10 -3 C/cm 2

E2F1 and p53 Transcription Factors as Accessory Factors for Nucleotide Excision Repair

Directory of Open Access Journals (Sweden)

David G. Johnson

2012-10-01

Full Text Available Many of the biochemical details of nucleotide excision repair (NER have been established using purified proteins and DNA substrates. In cells however, DNA is tightly packaged around histones and other chromatin-associated proteins, which can be an obstacle to efficient repair. Several cooperating mechanisms enhance the efficiency of NER by altering chromatin structure. Interestingly, many of the players involved in modifying chromatin at sites of DNA damage were originally identified as regulators of transcription. These include ATP-dependent chromatin remodelers, histone modifying enzymes and several transcription factors. The p53 and E2F1 transcription factors are well known for their abilities to regulate gene expression in response to DNA damage. This review will highlight the underappreciated, transcription-independent functions of p53 and E2F1 in modifying chromatin structure in response to DNA damage to promote global NER.

Contribution to the damage measurement of reinforced concrete buildings under seismic solicitations: proposal of an improvement for the evaluation of the damaging potential of a signal and of the damage for the girders structures: introduction to the reliability analysis of the damage in terms of the damaging potential of a seismic signal

International Nuclear Information System (INIS)

Naze, P.A.

2004-12-01

Building damage measurement during and after an earthquake remains an economical as well as technical stake as difficult to cope with as the problem it raises all the more because its importance depends on the field or the building function: civil, medical, military, nuclear... Even building ruin remains one of the most critical diagnosis to establish. Then since prediction of earthquake still remains impossible, foreseeing structural damages due to seismic motion has become a key point in earthquake engineering. This work aims at evaluating the relevance of classical seismic signal damaging potential indices and at proposing improvement of these indices in order to provide better prediction of structural damage due to earthquake. The first part supplies a non exhaustive state of the art of main Damaging Potential Indices IP and Damage Indices ID used in earthquake engineering. In the second part, IP/ID correlations results are analysed in order to evaluate IP relevance, to justify displacement based approach use (capacity spectrum method) for damage prediction and to make good the proposal for improvement of Damaging Potential Index. But studding seismic signal damaging potential is usually not enough to foresee damage firstly because scalar representation of damaging potential is not easy to link to physics reality and secondly because of damage scattering often observed for a single value of seismic signal damaging potential. In the same way, a single damage index value may correspond to very different structural damage states. Hence, this work carries on with a contribution to damage index reliability improvement, able to detect real structural damage appearance as well as to quantify this damage by associating the distance between one structural sate and the structural collapse, defined as an instability. (author)

Clinical light damage to the eye

International Nuclear Information System (INIS)

Miller, D.

1987-01-01

This book contains four sections: The Nature of Light and of Light Damage to Biological Tissues; Light Damage to the Eye; Protecting the Eye from Light Damage; and Overview of Light Damage to the Eye. Some of the paper titles are: Ultraviolet-Absorbing Intraocular Lens Implants; Phototoxic Changes in the Retina; Light Damage to the Lens; and Radiation, Light, and Sight

Reconstructing patterns of temperature, phenology, and frost damage over 124 years: spring damage risk is increasing.

Science.gov (United States)

Augspurger, Carol K

2013-01-01

Climate change, with both warmer spring temperatures and greater temperature fluctuations, has altered phenologies, possibly leading to greater risk of spring frost damage to temperate deciduous woody plants. Phenological observations of 20 woody species from 1993 to 2012 in Trelease Woods, Champaign County, Illinois, USA, were used to identify years with frost damage to vegetative and reproductive phases. Local temperature records were used in combination with the phenological observations to determine what combinations of the two were associated with damage. Finally, a long-term temperature record (1889-1992) was evaluated to determine if the frequency of frost damage has risen in recent decades. Frost Frost damage occurred in five years in the interior and in three additional years at only the forest edge. The degree of damage varied with species, life stage, tissue (vegetative or reproductive), and phenological phase. Common features associated with the occurrence of damage to interior plants were (1) a period of unusual warm temperatures in March, followed by (2) a frost event in April with a minimum temperature frost damage increased significantly, from 0.03 during 1889-1979 to 0.21 during 1980-2012. When the criteria were "softened" to frost damage events more common.

SUMO-2 Orchestrates Chromatin Modifiers in Response to DNA Damage

DEFF Research Database (Denmark)

Hendriks, Ivo A; Treffers, Louise W; Verlaan-de Vries, Matty

2015-01-01

dynamically SUMOylated interaction networks of chromatin modifiers, transcription factors, DNA repair factors, and nuclear body components. SUMOylated chromatin modifiers include JARID1B/KDM5B, JARID1C/KDM5C, p300, CBP, PARP1, SetDB1, and MBD1. Whereas SUMOylated JARID1B was ubiquitylated by the SUMO......-targeted ubiquitin ligase RNF4 and degraded by the proteasome in response to DNA damage, JARID1C was SUMOylated and recruited to the chromatin to demethylate histone H3K4....

Effects of chemical-induced DNA damage on male germ cells

Energy Technology Data Exchange (ETDEWEB)

Holme, J.A.; Bjoerge, C.; Trbojevic, M.; Olsen, A.K.; Brunborg, G.; Soederlund, E.J. [National Inst. of Public Health, Oslo (Norway). Dept. of Environmental Medicine; Bjoeras, M.; Seeberg, E. [National Hospital, Oslo (Norway). Dept. of Microbiology; Scholz, T.; Dybing, E.; Wiger, R. [National Hospital, Oslo (Norway). Inst. for Surgical Research and Surgical Dept. B

1998-12-31

Several recent studies indicate declines in sperm production, as well as increases in the incidence of genitourinary abnormalities such as testicular cancer, cryptorchidism and hypospadias. It is not known if these effects are due to exposure to chemical pollutants or if other ethiological factors are involved. Animal studies indicate that chemicals will induce such effects by various genetic, epigenetic or non-genetic mechanisms. Recently, much attention has been focused on embryonic/fetal exposure to oestrogen-mimicking chemicals (Toppari et al., 1996). However, the possibility that chemicals may cause reproductive toxicity by other mechanisms such as interactions with DNA, should not be ignored. DNA damage in germ cells may lead to the production of mutated spermatozoa, which in turn may result in spontaneous abortions, malformations and/or genetic defects in the offspring. Regarding the consequences of DNA alterations for carcinogenesis it is possible that genetic damage may occur germ cells, but the consequences are not expressed until certain genetic events occur in postnatal life. Transmission of genetic risk is best demonstrated by cancer-prone disorders such as hereditary retinoblastoma and the Li-Fraumeni syndrome. A number of experiments indicate that germ cells and proliferating cells may be particularly sensitive to DNA damaging agents compared to other cells. Furthermore, several lines of evidence have indicated that one of the best documented male reproductive toxicants, 1,2-dibrome-3-chloropropane (DBCP), causes testicular toxicity through DNA damage. It is possible that testicular cells at certain maturational stages are more subject to DNA damage, have less efficient DNA repair, or have different thresholds for initiating apoptosis following DNA damage than other cell types. (orig.)

Research on damage evolution and damage model of 316LN steel during forging

Energy Technology Data Exchange (ETDEWEB)

Duan, X.W., E-mail: dxwmike1998@sina.com; Liu, J.S.

2013-12-20

The tensile tests and unloading tensile experiments of 316LN steel were conducted. The damage evolution processes were investigated by optical microscope. The fracture was studied using a Scanning Electron Microscope (SEM) and optical microscope, of which, the chemical compositions were analyzed by Energy Dispersive Spectrometer (EDS). The results show that voids nucleate by decohesion of Al{sub 2}O{sub 3} inclusions–matrix interface and mainly along the grain boundary, especially, at triangular grain boundary junctions. The tensile processes were simulated by Deform2D under different deformation conditions. The critical damage values were obtained. The model between the critical damage value, temperature and strain rate was established by regression analysis. A combination of numerical simulation and upsetting experiments was applied for verifying the accuracy and reliability of critical damage value. These damage values can be used to predict the initiation of voids during 316LN steel hot forging. So, they have important instructional effects on designing forging technology of 316LN steel.

Air pollution and brain damage.

Science.gov (United States)

Calderón-Garcidueñas, Lilian; Azzarelli, Biagio; Acuna, Hilda; Garcia, Raquel; Gambling, Todd M; Osnaya, Norma; Monroy, Sylvia; DEL Tizapantzi, Maria Rosario; Carson, Johnny L; Villarreal-Calderon, Anna; Rewcastle, Barry

2002-01-01

Exposure to complex mixtures of air pollutants produces inflammation in the upper and lower respiratory tract. Because the nasal cavity is a common portal of entry, respiratory and olfactory epithelia are vulnerable targets for toxicological damage. This study has evaluated, by light and electron microscopy and immunohistochemical expression of nuclear factor-kappa beta (NF-kappaB) and inducible nitric oxide synthase (iNOS), the olfactory and respiratory nasal mucosae, olfactory bulb, and cortical and subcortical structures from 32 healthy mongrel canine residents in Southwest Metropolitan Mexico City (SWMMC), a highly polluted urban region. Findings were compared to those in 8 dogs from Tlaxcala, a less polluted, control city. In SWMMC dogs, expression of nuclear neuronal NF-kappaB and iNOS in cortical endothelial cells occurred at ages 2 and 4 weeks; subsequent damage included alterations of the blood-brain barrier (BBB), degenerating cortical neurons, apoptotic glial white matter cells, deposition of apolipoprotein E (apoE)-positive lipid droplets in smooth muscle cells and pericytes, nonneuritic plaques, and neurofibrillary tangles. Persistent pulmonary inflammation and deteriorating olfactory and respiratory barriers may play a role in the neuropathology observed in the brains of these highly exposed canines. Neurodegenerative disorders such as Alzheimer's may begin early in life with air pollutants playing a crucial role.

Polo-like kinase 1 inhibits DNA damage response during mitosis

Czech Academy of Sciences Publication Activity Database

Benada, Jan; Burdová, Kamila; Liďák, Tomáš; von Morgen, Patrick; Macůrek, Libor

2015-01-01

Roč. 14, č. 2 (2015), s. 219-231 ISSN 1538-4101 R&D Projects: GA ČR GAP305/12/2485; GA MŠk LO1220 Institutional support: RVO:68378050 Keywords : 53BP1 * DNA damage response * Polo like kinase 1 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.952, year: 2015

PCA-based detection of damage in time-varying systems

Science.gov (United States)

Bellino, A.; Fasana, A.; Garibaldi, L.; Marchesiello, S.

2010-10-01

When performing Structural Health Monitoring, it is well known that the natural frequencies do not depend only on the damage but also on environmental conditions, such as temperature and humidity. The Principal Component Analysis is used to take this problem into account, because it allows eliminating the effect of external factors. The purpose of the present work is to show that this technique can be successfully used not only for time-invariant systems, but also for time-varying ones. Referring to the latter, one of the most studied systems which shows these characteristics is the bridge with crossing loads, such as the case of the railway bridge studied in present paper; in this case, the mass and the velocity of the train can be considered as "environmental" factors.This paper, after a brief description of the PCA method and one example of its application on time-invariant systems, presents the great potentialities of the methodology when applied to time-varying systems. The results show that this method is able to better detect the presence of damage and also to properly distinguish among different levels of crack depths.

Radiation damage in natural materials: implications for radioactive waste forms

International Nuclear Information System (INIS)

Ewing, R.C.

1981-01-01

The long-term effect of radiation damage on waste forms, either crystalline or glass, is a factor in the evaluation of the integrity of waste disposal mediums. Natural analogs, such as metamict minerals, provide one approach for the evaluaton of radiation damage effects that might be observed in crystalline waste forms, such as supercalcine or synroc. Metamict minerals are a special class of amorphous materials which were initially crystalline. Although the mechanism for the loss of crystallinity in these minerals (mostly actinide-containing oxides and silicates) is not clearly understood, damage caused by alpha particles and recoil nuclei is critical to the metamictization process. The study of metamict minerals allows the evaluation of long-term radiation damage effects, particularly changes in physical and chemical properties such as microfracturing, hydrothermal alteration, and solubility. In addition, structures susceptible to metamictization share some common properties: (1) complex compositions; (2) some degree of covalent bonding, instead of being ionic close-packed MO/sub x/ structures; and (3) channels or interstitial voids which may accommodate displaced atoms or absorbed water. On the basis of these empirical criteria, minerals such as pollucite, sodalite, nepheline and leucite warrant careful scrutiny as potential waste form phases. Phases with the monazite or fluorite structures are excellent candidates

A review of damage detection methods for wind turbine blades

International Nuclear Information System (INIS)

Li, Dongsheng; Song, Gangbing; Ren, Liang; Li, Hongnan; Ho, Siu-Chun M

2015-01-01

Wind energy is one of the most important renewable energy sources and many countries are predicted to increase wind energy portion of their whole national energy supply to about twenty percent in the next decade. One potential obstacle in the use of wind turbines to harvest wind energy is the maintenance of the wind turbine blades. The blades are a crucial and costly part of a wind turbine and over their service life can suffer from factors such as material degradation and fatigue, which can limit their effectiveness and safety. Thus, the ability to detect damage in wind turbine blades is of great significance for planning maintenance and continued operation of the wind turbine. This paper presents a review of recent research and development in the field of damage detection for wind turbine blades. Specifically, this paper reviews frequently employed sensors including fiber optic and piezoelectric sensors, and four promising damage detection methods, namely, transmittance function, wave propagation, impedance and vibration based methods. As a note towards the future development trend for wind turbine sensing systems, the necessity for wireless sensing and energy harvesting is briefly presented. Finally, existing problems and promising research efforts for online damage detection of turbine blades are discussed. (topical review)

Local heart irradiation of ApoE−/− mice induces microvascular and endocardial damage and accelerates coronary atherosclerosis

International Nuclear Information System (INIS)

Gabriels, Karen; Hoving, Saske; Seemann, Ingar; Visser, Nils L.; Gijbels, Marion J.; Pol, Jeffrey F.; Daemen, Mat J.; Stewart, Fiona A.; Heeneman, Sylvia

2012-01-01

Background and purpose: Radiotherapy of thoracic and chest-wall tumors increases the long-term risk of radiation-induced heart disease, like a myocardial infarct. Cancer patients commonly have additional risk factors for cardiovascular disease, such as hypercholesterolemia. The goal of this study is to define the interaction of irradiation with such cardiovascular risk factors in radiation-induced damage to the heart and coronary arteries. Material and methods: Hypercholesterolemic and atherosclerosis-prone ApoE −/− mice received local heart irradiation with a single dose of 0, 2, 8 or 16 Gy. Histopathological changes, microvascular damage and functional alterations were assessed after 20 and 40 weeks. Results: Inflammatory cells were significantly increased in the left ventricular myocardium at 20 and 40 weeks after 8 and 16 Gy. Microvascular density decreased at both follow-up time-points after 8 and 16 Gy. Remaining vessels had decreased alkaline phosphatase activity (2–16 Gy) and increased von Willebrand Factor expression (16 Gy), indicative of endothelial cell damage. The endocardium was extensively damaged after 16 Gy, with foam cell accumulations at 20 weeks, and fibrosis and protein leakage at 40 weeks. Despite an accelerated coronary atherosclerotic lesion development at 20 weeks after 16 Gy, gated SPECT and ultrasound measurements showed only minor changes in functional cardiac parameters at 20 weeks. Conclusions: The combination of hypercholesterolemia and local cardiac irradiation induced an inflammatory response, microvascular and endocardial damage, and accelerated the development of coronary atherosclerosis. Despite these pronounced effects, cardiac function of ApoE −/− mice was maintained.

Forecast on Water Locking Damage of Low Permeable Reservoir with Quantum Neural Network

Science.gov (United States)

Zhao, Jingyuan; Sun, Yuxue; Feng, Fuping; Zhao, Fulei; Sui, Dianjie; Xu, Jianjun

2018-01-01

It is of great importance in oil-gas reservoir protection to timely and correctly forecast the water locking damage, the greatest damage for low permeable reservoir. An analysis is conducted on the production mechanism and various influence factors of water locking damage, based on which a quantum neuron is constructed based on the information processing manner of a biological neuron and the principle of quantum neural algorithm, besides, the quantum neural network model forecasting the water locking of the reservoir is established and related software is also made to forecast the water locking damage of the gas reservoir. This method has overcome the defects of grey correlation analysis that requires evaluation matrix analysis and complicated operation. According to the practice in Longxi Area of Daqing Oilfield, this method is characterized by fast operation, few system parameters and high accuracy rate (the general incidence rate may reach 90%), which can provide reliable support for the protection technique of low permeable reservoir.

Assessment of folic acid and DNA damage in cleft lip and cleft palate

Directory of Open Access Journals (Sweden)

Sivakumar Brooklyin

2014-03-01

Full Text Available Studies have identified the risk factors like folic acid deficiency during gestational period, family history for orofacial clefts, drugs like antiepileptic, vitamin A. But, the data regarding the folic acid status in children with cleft lip/palate is hardly evaluated in depth. Here, an assessment of folic acid and DNA damage were carried out in children with orofacial anomalies. Folic acid level and DNA damage were evaluated by folic acid assay (direct chemiluminescent technology and single cell gel electrophoresis or comet assay method respectively. The mean value of plasma folic acid by direct chemiluminescent technology was 6.5±3.6 nmol/L and the normal value in children ranges from 11.3 to 47.6 nmol/L. The amount of damaged DNA, measured as the tail length of the comet in cases, was 19.4±8.9 ?m and the mean percentage of DNA in tail was 16.5±3.7. Folic acid deficiency could be the reason for DNA damage.

New discoveries linking transcription to DNA repair and damage tolerance pathways.

Science.gov (United States)

Cohen, Susan E; Walker, Graham C

2011-01-01

In Escherichia coli, the transcription elongation factor NusA is associated with all elongating RNA polymerases where it functions in transcription termination and antitermination. Here, we review our recent results implicating NusA in the recruitment of DNA repair and damage tolerance mechanisms to sites of stalled transcription complexes.

Causes of keel bone damage and their solutions in laying hens

NARCIS (Netherlands)

Harlander-Matauschek, A.; Rodenburg, T.B.; Sandilands, V.; Tobalske, B.W.; Toscano, M.J.

2015-01-01

Keel bone damage (KBD) is a critical issue facing the contemporary laying hen industry due to the likely pain leading to compromised welfare and reduced productivity. Recent reports suggest that KBD, while highly variable and likely dependent on a host of factors, extends to all housing systems

Monument Damage Information System (mondis): AN Ontological Approach to Cultural Heritage Documentation

Science.gov (United States)

Cacciotti, R.; Valach, J.; Kuneš, P.; Čerňanský, M.; Blaško, M.; Křemen, P.

2013-07-01

Deriving from the complex nature of cultural heritage conservation it is the need for enhancing a systematic but flexible organization of expert knowledge in the field. Such organization should address comprehensively the interrelations and complementariness among the different factors that come into play in the understanding of diagnostic and intervention problems. The purpose of MONDIS is to endorse this kind of organization. The approach consists in applying an ontological representation to the field of heritage conservation in order to establish an appropriate processing of data. The system allows replicating in a computer readable form the basic dependence among factors influencing the description, diagnosis and intervention of damages to immovable objects. More specifically MONDIS allows to input and search entries concerning object description, structural evolution, location characteristics and risk, component, material properties, surveys and measurements, damage typology, damage triggering events and possible interventions. The system supports searching features typical of standard databases, as it allows for the digitalization of a wide range of information including professional reports, books, articles and scientific papers. It also allows for computer aided retrieval of information tailored to user's requirements. The foreseen outputs will include a web user interface and a mobile application for visual inspection purposes.

Spontaneous genetic damage in the tegu lizard (Tupinambis merianae): the effect of age.

Science.gov (United States)

Schaumburg, Laura G; Poletta, Gisela L; Siroski, Pablo A; Mudry, Marta D

2014-05-15

Several studies indicate that certain factors such as age, sex or nutritional status among others, may affect the level of DNA damage, both induced and spontaneous, so it is very important to consider them for a more accurate interpretation of the findings. The aim of this study was to analyze the influence of age, sex, and nest of origin on spontaneous genetic damage of Tupinambis merianae determined by the comet assay (CA) and the micronucleus (MN) test, in order to improve reference data for future in vivo studies of xenobiotics exposure in this species. Sixty-five tegu lizards of three different ages: newborns (NB), juveniles (JUV) and adults (AD), both sexes and from different nests of origin were used. Blood samples were collected from the caudal vein of all animals and the MN test and CA were applied on peripheral blood erythrocytes to determine basal frequency of MN (BFMN) and basal damage index (BDI). The comparison between age groups showed statistically significant differences in the BFMN and BDI (p0.05). A weak negative relationship was found only between BFMN and weight of NB tegu lizard (p=0.014; R(2)=0.245). Basal values of genetic damage obtained with both biomarkers in the tegu lizard evidenced that age is an intrinsic factor that should be taken into account to avoid misunderstanding of the results in future biomonitoring studies. Copyright © 2014 Elsevier B.V. All rights reserved.

DNA damage preceding dopamine neuron degeneration in A53T human α-synuclein transgenic mice.

Science.gov (United States)

Wang, Degui; Yu, Tianyu; Liu, Yongqiang; Yan, Jun; Guo, Yingli; Jing, Yuhong; Yang, Xuguang; Song, Yanfeng; Tian, Yingxia

2016-12-02

Defective DNA repair has been linked with age-associated neurodegenerative disorders. Parkinson's disease (PD) is a progressive neurodegenerative disorder caused by genetic and environmental factors. Whether damages to nuclear DNA contribute to neurodegeneration of PD still remain obscure. in this study we aim to explore whether nuclear DNA damage induce dopamine neuron degeneration in A53T human α-Synuclein over expressed mouse model. We investigated the effects of X-ray irradiation on A53T-α-Syn MEFs and A53T-α-Syn transgene mice. Our results indicate that A53T-α-Syn MEFs show a prolonged DNA damage repair process and senescense phenotype. DNA damage preceded onset of motor phenotype in A53T-α-Syn transgenic mice and decrease the number of nigrostriatal dopaminergic neurons. Neurons of A53T-α-Syn transgenic mice are more fragile to DNA damages. Copyright © 2016 Elsevier Inc. All rights reserved.

Micromechanics-Based Damage Analysis of Fracture in Ti5553 Alloy with Application to Bolted Sectors

Science.gov (United States)

Bettaieb, Mohamed Ben; Van Hoof, Thibaut; Minnebo, Hans; Pardoen, Thomas; Dufour, Philippe; Jacques, Pascal J.; Habraken, Anne Marie

2015-03-01

A physics-based, uncoupled damage model is calibrated using cylindrical notched round tensile specimens made of Ti5553 and Ti-6Al-4V alloys. The fracture strain of Ti5553 is lower than for Ti-6Al-4V in the full range of stress triaxiality. This lower ductility originates from a higher volume fraction of damage sites. By proper heat treatment, the fracture strain of Ti5553 increases by almost a factor of two, as a result of a larger damage nucleation stress. This result proves the potential for further optimization of the damage resistance of the Ti5553 alloy. The damage model is combined with an elastoviscoplastic law in order to predict failure in a wide range of loading conditions. In particular, a specific application involving bolted sectors is addressed in order to determine the potential of replacing the Ti-6Al-4V by the Ti5553 alloy.

Ubiquitin ligase activity of TFIIH and the transcriptional response to DNA damage.

Science.gov (United States)

Takagi, Yuichiro; Masuda, Claudio A; Chang, Wei-Hau; Komori, Hirofumi; Wang, Dong; Hunter, Tony; Joazeiro, Claudio A P; Kornberg, Roger D

2005-04-15

Core transcription factor (TF) IIH purified from yeast possesses an E3 ubiquitin (Ub) ligase activity, which resides, at least in part, in a RING finger (RNF) domain of the Ssl1 subunit. Yeast strains mutated in the Ssl1 RNF domain are sensitive to ultraviolet (UV) light and to methyl methanesulfonate (MMS). This increased sensitivity to DNA-damaging agents does not reflect a deficiency in nucleotide excision repair. Rather, it correlates with reduced transcriptional induction of genes involved in DNA repair, suggesting that the E3 Ub ligase activity of TFIIH mediates the transcriptional response to DNA damage.

Damage Detection and Deteriorating Structural Systems

DEFF Research Database (Denmark)

Long, Lijia; Thöns, Sebastian; Döhler, Michael

2017-01-01

This paper addresses the quantification of the value of damage detection system and algorithm information on the basis of Value of Information (VoI) analysis to enhance the benefit of damage detection information by providing the basis for its optimization before it is performed and implemented....... The approach of the quantification the value of damage detection information builds upon the Bayesian decision theory facilitating the utilization of damage detection performance models, which describe the information and its precision on structural system level, facilitating actions to ensure the structural...... detection information is determined utilizing Bayesian updating. The damage detection performance is described with the probability of indication for different component and system damage states taking into account type 1 and type 2 errors. The value of damage detection information is then calculated...

Damage-induced DNA repair processes in Escherichia coli cells

International Nuclear Information System (INIS)

Slezarikova, V.

1986-01-01

The existing knowledge is summed up of the response of Escherichia coli cells to DNA damage due to various factors including ultraviolet radiation. So far, three inducible mechanisms caused by DNA damage are known, viz., SOS induction, adaptation and thermal shock induction. Greatest attention is devoted to SOS induction. Its mechanism is described and the importance of the lexA recA proteins is shown. In addition, direct or indirect role is played by other proteins, such as the ssb protein binding the single-strand DNA sections. The results are reported of a study of induced repair processes in Escherichia coli cells repeatedly irradiated with UV radiation. A model of induction by repeated cell irradiation discovered a new role of induced proteins, i.e., the elimination of alkali-labile points in the daughter DNA synthetized on a damaged model. The nature of the alkali-labile points has so far been unclear. In the adaptation process, regulation proteins are synthetized whose production is induced by the presence of alkylation agents. In the thermal shock induction, new proteins synthetize in cells, whose function has not yet been clarified. (E.S.)

Cell damage by bilirubin and light

International Nuclear Information System (INIS)

Granli, T.

1993-01-01

Large doses of light are given to newborns during phototherapy for hyperbilirubinemia. Tissues containing concentrations of bilirubin almost in the mM range may be subjected to irradiation. Therefore it is of interest to study cellular effects of light and bilirubin on cells. In order to select the optimal wavelength, possible detrimental effects of light on cells must be taken into consideration among a number of other factors. In this study cellular effects of selected wavelengths of blue-green light are compared. It is not clear whether cullular damage occurs in vivo during phototherapy of newborns. Since a possibility exists that some adverse effects are caused by light, one should choose wavelengths where these effects are minimal without loosing therapeutic efficiency. Todays knowledge of the photochemical mechanisms of phototherapy, indicates that short waved light with wavelengths below 450 nm has a low therapeutic effect. The data in this paper indicate that the cellular damage is most severe at short wavelengths, and these should be reduced to a minimum in the spectra of phototherapy lamps. Further studies of possible side effects of phototherapy should be made. 64 refs., 34 figs., 1 tab

"Fair" Mathematics in Assessing Delictual Damages

Directory of Open Access Journals (Sweden)

L Steynberg

2011-05-01

Full Text Available In assessing delictual damages the plaintiff is burdened with the duty to prove loss with a preponderance of probability, including uncertain future loss. In quantifying such a claim an actuary is often used to make actuarial calculations based on proven facts and realistic assumptions regarding the future. The role of the actuary is to guide the court in the calculations to be made. Relying on its wide judicial discretion the court will have the final say regarding the correctness of the assumptions on which these calculations are based. The court should give detailed reasons if any assumptions or parts of the calculations made by the actuary are rejected. It should preferably refrain from making its own calculations if an actuary is involved and should rather instruct the actuary to do recalculations if necessary. It does, however, fall within the wide discretion of the court to make a general contingency adjustment after the basic calculations have been accepted. In assessing delictual damages it is the duty of the court to ensure that both objective and subjective factors are considered in such a manner that the assessment may be regarded as an application of "fair" mathematics.

Chemomechanics of Damage Accumulation and Damage-Recovery Healing in Bituminous Asphalt Binders

NARCIS (Netherlands)

Pauli, A.T.

2014-01-01

As a contribution to the development of mutli-scale multi-physics approaches to modelling pavement performance, the present thesis considers the topic of damage accumulation accompanied by damage recover self-healing of the bituminous asphalt phase of pavement systems. It is found insightful that by

The evaluation of distributed damage in concrete based on sinusoidal modeling of the ultrasonic response.

Science.gov (United States)

Sepehrinezhad, Alireza; Toufigh, Vahab

2018-05-25

Ultrasonic wave attenuation is an effective descriptor of distributed damage in inhomogeneous materials. Methods developed to measure wave attenuation have the potential to provide an in-site evaluation of existing concrete structures insofar as they are accurate and time-efficient. In this study, material classification and distributed damage evaluation were investigated based on the sinusoidal modeling of the response from the through-transmission ultrasonic tests on polymer concrete specimens. The response signal was modeled as single or the sum of damping sinusoids. Due to the inhomogeneous nature of concrete materials, model parameters may vary from one specimen to another. Therefore, these parameters are not known in advance and should be estimated while the response signal is being received. The modeling procedure used in this study involves a data-adaptive algorithm to estimate the parameters online. Data-adaptive algorithms are used due to a lack of knowledge of the model parameters. The damping factor was estimated as a descriptor of the distributed damage. The results were compared in two different cases as follows: (1) constant excitation frequency with varying concrete mixtures and (2) constant mixture with varying excitation frequencies. The specimens were also loaded up to their ultimate compressive strength to investigate the effect of distributed damage in the response signal. The results of the estimation indicated that the damping was highly sensitive to the change in material inhomogeneity, even in comparable mixtures. In addition to the proposed method, three methods were employed to compare the results based on their accuracy in the classification of materials and the evaluation of the distributed damage. It is shown that the estimated damping factor is not only sensitive to damage in the final stages of loading, but it is also applicable in evaluating micro damages in the earlier stages providing a reliable descriptor of damage. In addition

Damage progression in silicon nitride undergoing non-conforming hybrid cyclic contact

Czech Academy of Sciences Publication Activity Database

Raga, R.; Khader, I.; Chlup, Zdeněk; Kailer, A.

2017-01-01

Roč. 105, DEC (2017), s. 97-110 ISSN 0142-1123 EU Projects: European Commission(XE) 263476 - ROLICER Institutional support: RVO:68081723 Keywords : Silicon nitride * Cyclic contact fatigue * Surface and subsurface damage Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis Impact factor: 2.899, year: 2016

The thyroid hormone receptor β induces DNA damage and premature senescence.

Science.gov (United States)

Zambrano, Alberto; García-Carpizo, Verónica; Gallardo, María Esther; Villamuera, Raquel; Gómez-Ferrería, Maria Ana; Pascual, Angel; Buisine, Nicolas; Sachs, Laurent M; Garesse, Rafael; Aranda, Ana

2014-01-06

There is increasing evidence that the thyroid hormone (TH) receptors (THRs) can play a role in aging, cancer and degenerative diseases. In this paper, we demonstrate that binding of TH T3 (triiodothyronine) to THRB induces senescence and deoxyribonucleic acid (DNA) damage in cultured cells and in tissues of young hyperthyroid mice. T3 induces a rapid activation of ATM (ataxia telangiectasia mutated)/PRKAA (adenosine monophosphate-activated protein kinase) signal transduction and recruitment of the NRF1 (nuclear respiratory factor 1) and THRB to the promoters of genes with a key role on mitochondrial respiration. Increased respiration leads to production of mitochondrial reactive oxygen species, which in turn causes oxidative stress and DNA double-strand breaks and triggers a DNA damage response that ultimately leads to premature senescence of susceptible cells. Our findings provide a mechanism for integrating metabolic effects of THs with the tumor suppressor activity of THRB, the effect of thyroidal status on longevity, and the occurrence of tissue damage in hyperthyroidism.

DNA damage responses in human induced pluripotent stem cells and embryonic stem cells.

Directory of Open Access Journals (Sweden)

Olga Momcilovic

2010-10-01

Full Text Available Induced pluripotent stem (iPS cells have the capability to undergo self-renewal and differentiation into all somatic cell types. Since they can be produced through somatic cell reprogramming, which uses a defined set of transcription factors, iPS cells represent important sources of patient-specific cells for clinical applications. However, before these cells can be used in therapeutic designs, it is essential to understand their genetic stability.Here, we describe DNA damage responses in human iPS cells. We observe hypersensitivity to DNA damaging agents resulting in rapid induction of apoptosis after γ-irradiation. Expression of pluripotency factors does not appear to be diminished after irradiation in iPS cells. Following irradiation, iPS cells activate checkpoint signaling, evidenced by phosphorylation of ATM, NBS1, CHEK2, and TP53, localization of ATM to the double strand breaks (DSB, and localization of TP53 to the nucleus of NANOG-positive cells. We demonstrate that iPS cells temporary arrest cell cycle progression in the G(2 phase of the cell cycle, displaying a lack of the G(1/S cell cycle arrest similar to human embryonic stem (ES cells. Furthermore, both cell types remove DSB within six hours of γ-irradiation, form RAD51 foci and exhibit sister chromatid exchanges suggesting homologous recombination repair. Finally, we report elevated expression of genes involved in DNA damage signaling, checkpoint function, and repair of various types of DNA lesions in ES and iPS cells relative to their differentiated counterparts.High degrees of similarity in DNA damage responses between ES and iPS cells were found. Even though reprogramming did not alter checkpoint signaling following DNA damage, dramatic changes in cell cycle structure, including a high percentage of cells in the S phase, increased radiosensitivity and loss of DNA damage-induced G(1/S cell cycle arrest, were observed in stem cells generated by induced pluripotency.

Uncertainty in urban flood damage assessment due to urban drainage modelling and depth-damage curve estimation.

Science.gov (United States)

Freni, G; La Loggia, G; Notaro, V

2010-01-01

Due to the increased occurrence of flooding events in urban areas, many procedures for flood damage quantification have been defined in recent decades. The lack of large databases in most cases is overcome by combining the output of urban drainage models and damage curves linking flooding to expected damage. The application of advanced hydraulic models as diagnostic, design and decision-making support tools has become a standard practice in hydraulic research and application. Flooding damage functions are usually evaluated by a priori estimation of potential damage (based on the value of exposed goods) or by interpolating real damage data (recorded during historical flooding events). Hydraulic models have undergone continuous advancements, pushed forward by increasing computer capacity. The details of the flooding propagation process on the surface and the details of the interconnections between underground and surface drainage systems have been studied extensively in recent years, resulting in progressively more reliable models. The same level of was advancement has not been reached with regard to damage curves, for which improvements are highly connected to data availability; this remains the main bottleneck in the expected flooding damage estimation. Such functions are usually affected by significant uncertainty intrinsically related to the collected data and to the simplified structure of the adopted functional relationships. The present paper aimed to evaluate this uncertainty by comparing the intrinsic uncertainty connected to the construction of the damage-depth function to the hydraulic model uncertainty. In this way, the paper sought to evaluate the role of hydraulic model detail level in the wider context of flood damage estimation. This paper demonstrated that the use of detailed hydraulic models might not be justified because of the higher computational cost and the significant uncertainty in damage estimation curves. This uncertainty occurs mainly

Dynamics of combined forest damage risks for 21st century (SRES A1B, B1)

Science.gov (United States)

Panferov, Oleg; Merklein, Johannes; Sogachev, Andrey; Junghans, Udo; Ahrends, Bernd

2010-05-01

The ongoing climate change can result in increasing frequency of weather extremes (Leckebusch et al., 2008) which in turn can produce wide area forest damage (windthrows, droughts, insect attacks) within forest ecosystems in Europe. The probability and extent of damage, depend not only on a strength of a driving force itself but especially on combinations of effecting agents and their interactions with forest ecosystem structure and soil properties. The combined effect of several factors which are not the extremes themselves can lead to the biotic and/or abiotic damage so that the combination becomes an extreme event. As soon as a damage event occurs, the forest structure is changed. The changes in forest structure in their turn strengthen or inhibits the influence of different climatic factors thus increase or decrease the probability of the next damage event creating positive or negative feedbacks. To assess the roles of separate meteorological factors and their combinations in forest damage under present and future climatic conditions the coupled model was created in University of Goettingen, as a part of a Decision Support System (Jansen et al, 2008, Panferov et al., 2009). The model combines the 3D ABL Model SCADIS (Panferov and Sogachev, 2008) with modified soil hydrology model BROOK 90 (Federer, 2003, Ahrends et al. 2009) and the model of climate dependent biotic damage. The projected future developments of forest damage events in 21st Century were carried out under conditions of SRES scenarios A1B and B1; the present conditions were evaluated using the measured data of German Weather Service. Climate scenario data of coupled ECHAM5-MPIOM were downscaled by the regional climate model Climate Local Model (CLM) to the spatial resolution of 0.2° x 0.2° and temporal resolution of 24 hours. Using these data as input the small-scale coupled process based modeling was then carried out for example region of Solling, Germany calculating the water and energy balance

Nuclear damage compensation and energy reform

International Nuclear Information System (INIS)

Yokemoto, Masafumi

2013-01-01

Nuclear damage compensation and energy reform were closely related. Nuclear damage compensation cost should be part of generation cost of nuclear power. Extend of nuclear damage compensation was limited by compensation standard of Tokyo Electric Power Co. (TEPCO) following guidelines of Dispute Reconciliation Committee for Nuclear Damage Compensation. TEPCO had already paid compensation of about two trillion yen until now, which was only a part of total damage compensation cost. TEPCO had been provided more than 3.4 trillion yen by Nuclear Damage Liability Facilitation Cooperation, which would be put back by nuclear operators including TEPCO. TEPCO could obtain present raising funds and try to reconstruct business with restart of nuclear power, which might disturb energy reform. Present nuclear damage compensation scheme had better be reformed with learning more from Minamata disease case in Japan. (T. Tanaka)

Damage buildup and edge dislocation mobility in equiatomic multicomponent alloys

Energy Technology Data Exchange (ETDEWEB)

Granberg, F., E-mail: fredric.granberg@helsinki.fi [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Djurabekova, F. [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Helsinki Institute of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Levo, E.; Nordlund, K. [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland)

2017-02-15

Highlights: • We studied the damage buildup in equiatomic multicomponent alloys by MD simulations. • Edge dislocation mobility was lower in the studied alloys compared to elemental Ni. • Damage buildup in alloys saturated at lower levels than in elemental Ni. • Initial damage buildup is faster in alloys compared to elemental Ni. - Abstract: A new class of single phase metal alloys of equal atomic concentrations has shown very promising mechanical properties and good corrosion resistance. Moreover, a significant reduction in damage accumulation during prolonged irradiation has also been observed in these equiatomic multicomponent alloys. A comparison of elemental Ni with the two component NiFe- and the three component NiCoCr-alloy showed a substantial reduction in damage in both alloys, and an even larger difference was seen if only larger clusters were considered. One of the factors limiting the damage build-up in the alloys compared to the elemental material was seen to be dislocation mobility (Granberg et al., 2016). In this Article, we focus on a more thorough investigation of the mobility of edge dislocations in different cases of the Ni-, NiFe- and NiCoCr-samples. We find that even though the saturated amount of defects in the alloys is lower than in elemental Ni, the defect buildup in the early stages is faster in the alloys. We also find that the dislocation mobility in NiFe is lower than in Ni, at low stresses, and that the onset stress in NiFe is higher than in Ni. The same phenomenon was seen in comparison between NiFe and NiCoCr, since the three component alloy had lower dislocation mobility and higher onset stress. The dislocation velocity in elemental Ni plateaued out just under the forbidden velocity, whereas the alloys showed a more complex behaviour.

Radon-induced DNA damage and apoptosis analyzed by flow cytometry

International Nuclear Information System (INIS)

Meenakshi, C.; Mohankumar, Mary N.

2012-01-01

Natural radiation is the major source of human exposure to ionizing radiation and its largest contributing component to effective doses arises from inhalation of 222 Rn and its radioactive progeny. 222 Rn, a chemically inert gas produced naturally from radium in rocks and soil is a proven source of lung cancer especially in closed environments such as mines and in poorly ventilated homes. Much of the data on the effect of radon in humans comes from epidemiological studies, often masked by confounding factors such as age, smoking and lifestyle. Radiation carcinogenesis is initiated by DNA damage and flow cytometry is a versatile, fast and accurate technique for the analysis of DNA damage as it offers the analysis of high number of individual cells in few minutes. An attempt was made to detect DNA damage and apoptosis after exposing human blood cells in vitro to radon by flow cytometry. Blood samples were collected from apparently healthy individuals and exposed in vitro to radon ranging between 1-5 mGy using a simple, portable irradiation assembly designed and tested at the Radiological Safety Division of Indira Gandhi Centre for Atomic Research. Cultures were initiated by the addition of phytohemagglutinin and cells were processed stained and analyzed for DNA damage and apoptosis by flow cytometry. CV values indicative of DNA damage were plotted against dose and were observed to increase in a dose dependent manner 3h after of irradiation. However no such response was observed at 24h and 48h. Nevertheless, the percentage of apoptotic cells increased steadily with dose after 24 and 48h post exposure. DNA breaks appear to be rejoined after about 24h of irradiation. However apoptotic cells increased with time and dose, suggesting elimination of highly damaged cells. Further experiments are needed to identify apoptotic cells as a biomarker of radiation exposure and risk. (author)

Steady State Shift Damage Localization

DEFF Research Database (Denmark)

Sekjær, Claus; Bull, Thomas; Markvart, Morten Kusk

2017-01-01

The steady state shift damage localization (S3DL) method localizes structural deterioration, manifested as either a mass or stiffness perturbation, by interrogating the damage-induced change in the steady state vibration response with damage patterns cast from a theoretical model. Damage is, thus...... the required accuracy when examining complex structures, an extensive amount of degrees of freedom (DOF) must often be utilized. Since the interrogation matrix for each damage pattern depends on the size of the system matrices constituting the FE-model, the computational time quickly becomes of first......-order importance. The present paper investigates two sub-structuring approaches, in which the idea is to employ Craig-Bampton super-elements to reduce the amount of interrogation distributions while still providing an acceptable localization resolution. The first approach operates on a strict super-element level...

Radiation Damage in Scintillating Crystals

CERN Document Server

Zhu Ren Yuan

1998-01-01

Crystal Calorimetry in future high energy physics experiments faces a new challenge to maintain its precision in a hostile radiation environment. This paper discusses the effects of radiation damage in scintillating crystals, and concludes that the predominant radiation damage effect in crystal scintillators is the radiation induced absorption, or color center formation, not the loss of the scintillation light yield. The importance of maintaining crystal's light response uniformity and the feasibility to build a precision crystal calorimeter under radiation are elaborated. The mechanism of the radiation damage in scintillating crystals is also discussed. While the damage in alkali halides is found to be caused by the oxygen or hydroxyl contamination, it is the structure defects, such as oxygen vacancies, cause damage in oxides. Material analysis methods used to reach these conclusions are presented in details.

Prediction of radiation-related small-bowel damage

International Nuclear Information System (INIS)

Potish, R.A.

1980-01-01

In order to predict which patients have a high risk for radiation-related small-bowel damage, the concept of the dose-response curve was applied to the predisposing factors (number of previous laparotomies, extent of surgery, thin physique, hypertension, age, cancer stage, number of treatment days, fractionation, and weight change during radiotherapy) present in 92 patients receiving identical radiation doses and volumes This analysis allows an estimate of the probability of complication to be assigned to individual patients. The utility and limitations of the dose-response concept are discussed

Topical application of ST266 reduces UV-induced skin damage

Directory of Open Access Journals (Sweden)

Guan L

2017-11-01

Full Text Available Linna Guan,1 Amanda Suggs,1 Emily Galan,1 Minh Lam,1 Elma D Baron1,2 1Department of Dermatology, Case Western Reserve University, 2Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA Abstract: Ultraviolet radiation (UVR has a significant impact on human skin and is the major environmental factor for skin cancer formation. It is also believed that 80% of the signs of skin aging are attributed to UVR. UVR induces inflammatory changes in the skin via the increase in oxidative stress, DNA damage vascular permeability, and fluctuation in a myriad of cytokines. Acutely, UVR causes skin inflammation and DNA damage, which manifest as sunburn (erythema. ST266 is the secretome of proprietary amnion-derived cells that have been shown to reduce inflammation and accelerate healing of various wounds by promoting migration of keratinocytes and fibroblasts in preclinical animal studies. We hypothesized that ST266 has anti-inflammatory effects that can be used to reduce ultraviolet (UV erythema and markers of inflammation. In this study, we examined the in vivo effects of ST266 on post UV-irradiated skin by measuring erythema, level of cyclobutane pyrimidine dimer (CPD, and expression level of xeroderma pigmentosum, complementation group A (XPA. We demonstrated that ST266 has the potential to reduce the acute effects of UV-induced skin damage when applied immediately after the initial exposure. In addition, ST266 is shown to reduce erythema, increase XPA DNA repair protein, and decrease damaged DNA. Keywords: ST266, photoaging, erythema, CPD, XPA, UV-induced DNA damage

Epigenetic Regulators Modulate Muscle Damage in Duchenne Muscular Dystrophy Model.

Science.gov (United States)

Bajanca, Fernanda; Vandel, Laurence

2017-12-21

Histone acetyl transferases (HATs) and histone deacetylases (HDAC) control transcription during myogenesis. HDACs promote chromatin condensation, inhibiting gene transcription in muscle progenitor cells until myoblast differentiation is triggered and HDACs are released. HATs, namely CBP/p300, activate myogenic regulatory and elongation factors promoting myogenesis. HDAC inhibitors are known to improve regeneration in dystrophic muscles through follistatin upregulation. However, the potential of directly modulating HATs remains unexplored. We tested this possibility in a well-known zebrafish model of Duchenne muscular dystrophy. Interestingly, CBP/p300 transcripts were found downregulated in the absence of Dystrophin. While investigating CBP rescuing potential we observed that dystrophin-null embryos overexpressing CBP actually never show significant muscle damage, even before a first regeneration cycle could occur. We found that the pan-HDAC inhibitor trichostatin A (TSA) also prevents early muscle damage, however the single HAT CBP is as efficient even in low doses. The HAT domain of CBP is required for its full rescuing ability. Importantly, both CBP and TSA prevent early muscle damage without restoring endogenous CBP/p300 neither increasing follistatin transcripts. This suggests a new mechanism of action of epigenetic regulators protecting dystrophin-null muscle fibres from detaching, independent from the known improvement of regeneration upon damage of HDACs inhibitors. This study builds supporting evidence that epigenetic modulators may play a role in determining the severity of muscle dystrophy, controlling the ability to resist muscle damage. Determining the mode of action leading to muscle protection can potentially lead to new treatment options for muscular dystrophies in the future.

Femoral nerve damage (image)

Science.gov (United States)

The femoral nerve is located in the leg and supplies the muscles that assist help straighten the leg. It supplies sensation ... leg. One risk of damage to the femoral nerve is pelvic fracture. Symptoms of femoral nerve damage ...

Investigation of damage threshold to TiO2 coatings at different laser wavelength and pulse duration

International Nuclear Information System (INIS)

Yao Jianke; Fan Zhengxiu; Jin Yunxia; Zhao Yuanan; He Hongbo; Shao Jianda

2008-01-01

Laser-induced damages to TiO 2 single layers and TiO 2 /SiO 2 high reflectors at laser wavelength of 1064 nm, 800 nm, 532 nm, and pulse width of 12 ns, 220 ps, 50 fs, 8 ns are investigated. All films are prepared by electron beam evaporation. The relations among microstructure, chemical composition, optical properties and laser-induced damage threshold (LIDT), have been researched. The dependence of damage mechanism on laser wavelength and pulse width is discussed. It is found that from 1064 nm to 532 nm, LIDT is mainly absorption related, which is determined by film's extinction coefficient and stoichiometric defects. The rapid decrease of LIDT at 800 nm is due to the pulse width factor. TiO 2 coatings are mainly thermally by damaged at long pulse (τ ≥ 220 ps). The damage shows ablation feature at 50 fs

Biologically important radiation damage in DNA

International Nuclear Information System (INIS)

Ward, J.F.

1994-01-01

Most DNA damage by the hydroxyl radical is confined to the bases, and this base damage represents an important component of locally multiply demanded sites (LMOS). The yields of the major damaged bases have been determined by gas chromatography mass spectrometry. For our propose, it was necessary to convert a known fraction of these damaged bases to strand breaks and then assay these labile sites as the increase in strand break yield over the normally observed level. Three potential agents by which this strategy of conversion of base damage to strand break could be implemented were identified in the original application: 1, Sl nuclease; 2, piperidine; and 3, base damage specific enzymes

Brief communication: On-site data collection of damage caused by flash floods: Experiences from Braunsbach, Germany, in May/June 2016

Science.gov (United States)

Laudan, Jonas; Rözer, Viktor; Sieg, Tobias; Vogel, Kristin; Thieken, Annegret

2017-04-01

At the end of May and beginning of June 2016, several municipalities in Southern Germany suffered from severe flash floods and debris flows which have been triggered by intense rainfall in Central Europe. Overall, the insured losses of these events amounted to EUR 1.2 billion in Germany. Especially the strong and unexpected flash flood on May 29th in Braunsbach (Baden Wurttemberg) - a small village counting about 1,000 residents - attracted media and policymakers due to its devastating character. The understanding of damage caused by flash floods requires ex-post collection of relevant but yet sparsely available information, linking process intensities to damage by using adequate methods of data gathering. Thus, on-site data collection was carried out after the flash flood event in Braunsbach, using open source software as helpful and efficient tool for data acquisition and evaluation. A digital survey was designed and conducted by a team of five researchers who investigated all buildings affected by water and debris flows. The collected data includes an estimation of a particular damage class, the inundation depth, and other relevant information. A post - hoc data analysis was done with R 3.3.1 and QGIS 2.14.3, performing both, a Random Forest Model (RF) and Random Generalized Linear Model (RGLM) as well as preparing a Spearman's rank correlation matrix. For visual interpretation and better overview of the study area and analysis results, a "process intensity" map was created, revealing important links of damage driving factors. We find that not only the water depth, which is often considered as only damage driving factor in riverine flood loss modelling, but also the exposition of a building to the flow direction and susceptible building parts like e.g. shop windows seem to be risk factors in flash-flood prone regions. Although no significant correlations were found, the analyses indicate that also building material (i.e. half-timbered or masonry) and structural

Damage costs due to automotive air pollution and the influence of street canyons

International Nuclear Information System (INIS)

Spadaro, Joseph V.; Rabl, Ari

2001-01-01

Using the methodology of the ExternE Project of the European Commission, we have evaluated the damage costs of automotive air pollution by way of two case studies in France: a trip across Paris, and a trip from Paris to Lyon. This methodology involves an analysis of the impact pathways, starting with the emissions (e.g., g/km of particles form tailpipe), followed by local and regional dispersion (e.g., incremental μg/m 3 of particles), calculation of the physical impacts using exposure-response functions (e.g., cases of respiratory hospital admissions), and finally multiplication by unit costs factors (e.g., ε per hospital admission). Damages are aggregated over all affected receptors in Europe. In addition to the local and regional dispersion calculations carried out so far by ExternE, we also consider the increased microscale impacts due to the trapping of pollutants in street canyons, using numerical simulations with the FLUENT software. We have evaluated impacts to human health, agricultural crops and building materials, due to particles, NO x , CO, HC and CO 2 . Health impacts, especially reduced life expectancy, dominate in terms of cost. Damages for older cars (before 1997) range from 2 to 41Euro cents/km, whereas for newer cars (since 1997), the range 1-9 Euro cents/km, and there is continuing progress in reducing the emissions further. In large cities, the particulate emissions of diesel cars lead to the highest damages, exceeding those of gasoline cars by a factor of 7. For cars before 1997 the order of magnitude of the damage costs is comparable to the price of gasoline, and the loss of life expectancy is comparable to that from traffic accidents. (Author)

Continuum Damage Mechanics A Continuum Mechanics Approach to the Analysis of Damage and Fracture

CERN Document Server

Murakami, Sumio

2012-01-01

Recent developments in engineering and technology have brought about serious and enlarged demands for reliability, safety and economy in wide range of fields such as aeronautics, nuclear engineering, civil and structural engineering, automotive and production industry.  This, in turn, has caused more interest in continuum damage mechanics and its engineering applications.   This book aims to give a concise overview of the current state of damage mechanics, and then to show the fascinating possibility of this promising branch of mechanics, and to provide researchers, engineers and graduate students with an intelligible and self-contained textbook.   The book consists of two parts and an appendix.  Part I  is concerned with the foundation of continuum damage mechanics.  Basic concepts of material damage and the mechanical representation of damage state of various kinds are described in Chapters 1 and 2.  In Chapters 3-5, irreversible thermodynamics, thermodynamic constitutive theory and its application ...

Damage Atlas for Photographic materials

Directory of Open Access Journals (Sweden)

Kristel Van Camp

2010-11-01

Full Text Available La conservation des documents photographiques peut nécessiter des interventions préventives ou curatives. Ce choix est guidé par leur état de conservation. Une meilleure connaissance des détériorations est donc cruciale. Le répertoire présenté ici essaie de les classifier selon des caractéristiques spécifiques et leur niveau de gravité. Les différents types de dégradation sont illustrés et décrits avec une terminologie précise. L’auteur propose en regard de ceux-ci l’intervention qui semble la plus appropriée. Ce répertoire s’adresse à toutes les personnes concernées par la photographie, qu’ils soient dans le milieu de la conservation ou dans le domaine artistique, dans les musées ou dans les archives. In order to rescue a damaged photographic object, preventive or conservative actions are needed. Knowing the specific characteristics of different types of damage is crucial. A damage atlas can provide these characteristics. With this atlas the damage can be recognised and appropriate actions can be taken. This damage atlas offers a first attempt to such a characterisation in the field of photography. The damage atlas contains images and the necessary information about damage on photographic material. The atlas with special annotations about the terminology and the grade of the damage is meant for everybody who works with photographic material, as well in museums as in archives.

Damage sensing ability of polymer nanocomposites filled with long, shortened and damaged carbon nanotubes

OpenAIRE

Inam, Fawad; Okolo, Chichi; Vo, Thuc

2016-01-01

Carbon nanotubes (CNTs) were aggressively tip-ultrasonicated to produce shortened and damaged carbon nanotubes. High-resolution scanning electron microscopic analysis was performed to measure the dimensions of CNTs. Thermo-gravimetric analysis (TGA) was used to evaluate the damage in the sonicated CNTs. Shortened CNTs, in their pristine form (undamaged), were used for comparison with damaged CNTs. Nanocomposite bars, containing CNTs, were indented using Vickers hardness testing machine to pro...

Ion irradiation damage in ilmenite at 100 K

International Nuclear Information System (INIS)

Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.

1997-01-01

A natural single crystal of ilmenite (FeTiO 3 ) was irradiated at 100 K with 200 keV Ar 2+ . Rutherford backscattering spectroscopy and ion channeling with MeV He + ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 x 10 15 Ar 2+ cm -2 , considerable near-surface He + ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 nm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO 3 ) and spinel (MgAl 2 O 4 ) to explore factors that may influence radiation damage response in oxides

Ion irradiation damage in ilmenite under cryogenic conditions

International Nuclear Information System (INIS)

Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.

1996-01-01

A natural single crystal of ilmenite was irradiated at 100 K with 200 keV Ar 2+ . Rutherford backscattering spectroscopy and ion channeling with 2 MeV He + ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 x 10 15 Ar 2+ cm -2 , considerable near-surface He + ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 mm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO 3 ) and spinel (MgAl 2 O 4 ) to explore factors that may influence radiation damage response in oxides

Ion irradiation damage in ilmenite at 100 K

Science.gov (United States)

Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.; Nord, G.L.

1997-01-01

A natural single crystal of ilmenite (FeTiO3) was irradiated at 100 K with 200 keV Ar2+. Rutherford backscattering spectroscopy and ion channeling with 2 MeV He+ ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 ?? 1015 Ar2+/cm2, considerable near-surface He+ ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 nm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO3) and spinel (MgAl2O4) to explore factors that may influence radiation damage response in oxides.

Damage Models for Soft Tissues: A Survey.

Science.gov (United States)

Li, Wenguang

Damage to soft tissues in the human body has been investigated for applications in healthcare, sports, and biomedical engineering. This paper reviews and classifies damage models for soft tissues to summarize achievements, identify new directions, and facilitate finite element analysis. The main ideas of damage modeling methods are illustrated and interpreted. A few key issues related to damage models, such as experimental data curve-fitting, computational effort, connection between damage and fractures/cracks, damage model applications, and fracture/crack extension simulation, are discussed. Several new challenges in the field are identified and outlined. This review can be useful for developing more advanced damage models and extending damage modeling methods to a variety of soft tissues.

Conformational variation of proteins at room temperature is not dominated by radiation damage

International Nuclear Information System (INIS)

Russi, Silvia; González, Ana; Kenner, Lillian R.; Keedy, Daniel A.; Fraser, James S.; Bedem, Henry van den

2017-01-01

Protein crystallography data collection at synchrotrons is routinely carried out at cryogenic temperatures to mitigate radiation damage. Although damage still takes place at 100 K and below, the immobilization of free radicals increases the lifetime of the crystals by approximately 100-fold. Recent studies have shown that flash-cooling decreases the heterogeneity of the conformational ensemble and can hide important functional mechanisms from observation. These discoveries have motivated increasing numbers of experiments to be carried out at room temperature. However, the trade-offs between increased risk of radiation damage and increased observation of alternative conformations at room temperature relative to cryogenic temperature have not been examined. A considerable amount of effort has previously been spent studying radiation damage at cryo-temperatures, but the relevance of these studies to room temperature diffraction is not well understood. Here, the effects of radiation damage on the conformational landscapes of three different proteins (T. danielli thaumatin, hen egg-white lysozyme and human cyclophilin A) at room (278 K) and cryogenic (100 K) temperatures are investigated. Increasingly damaged datasets were collected at each temperature, up to a maximum dose of the order of 10 7 Gy at 100 K and 10 5 Gy at 278 K. Although it was not possible to discern a clear trend between damage and multiple conformations at either temperature, it was observed that disorder, monitored by B-factor-dependent crystallographic order parameters, increased with higher absorbed dose for the three proteins at 100 K. At 278 K, however, the total increase in this disorder was only statistically significant for thaumatin. A correlation between specific radiation damage affecting side chains and the amount of disorder was not observed. Lastly, this analysis suggests that elevated conformational heterogeneity in crystal structures at room temperature is observed despite radiation

Review of Repair Materials for Fire-Damaged Reinforced Concrete Structures

Science.gov (United States)

Zahid, MZA Mohd; Abu Bakar, BH; Nazri, FM; Ahmad, MM; Muhamad, K.

2018-03-01

Reinforced concrete (RC) structures perform well during fire and may be repaired after the fire incident because their low heat conductivity prevents the loss or degradation of mechanical strength of the concrete core and internal reinforcing steel. When an RC structure is heated to more than 500 °C, mechanical properties such as compressive strength, stiffness, and tensile strength start to degrade and deformations occur. Although the fire-exposed RC structure shows no visible damage, its residual strength decreases compared with that in the pre-fire state. Upon thorough assessment, the fire-damaged RC structure can be repaired or strengthened, instead of subjecting to partial or total demolition followed by reconstruction. The structure can be repaired using several materials, such as carbon fiber-reinforced polymer, glass fiber-reinforced polymer, normal strength concrete, fiber-reinforced concrete, ferrocement, epoxy resin mortar, and high-performance concrete. Selecting an appropriate repair material that must be compatible with the substrate or base material is a vital step to ensure successful repair. This paper reviews existing repair materials and factors affecting their performance. Of the materials considered, ultra-high-performance fiber-reinforced concrete (UHPFRC) exhibits huge potential for repairing fire-damaged RC structures but lack of information available. Hence, further studies must be performed to assess the potential of UHPFRC in rehabilitating fire-damaged RC structures.

Modification of radiation damage in CHO cells by hyperthermia at 40 and 450C

International Nuclear Information System (INIS)

Henle, K.J.; Leeper, D.B.

1977-01-01

Low hyperthermia at 40 0 C either before or after X irradiation did not alter the slope of the radiation dose-cell survival curve but reduced the D/sub q/ from 145 to 41 or to 0 rad for a pre- or postirradiation incubation period of 2 hr at 40 0 C, respectively. In contrast, hyperthermia at 45 0 C increased the slope of the radiation survival curve by a factor of 1.7 for a radiation pretreatment of 10 min at 45 0 C, but only by 1.3 for the same treatment immediately after irradiation. The corresponding D/sub q/'s were 262 and 138 rad, respectively. A combination of 45 and 40 0 C hyperthermia (10 min at 45 0 C + 2 hr at 40 0 C + X) resulted in a superposition of the individual effects of 45 or 40 0 C hyperthermia on the radiation survival curve. In addition, the radiation survival curve was shifted downward by a factor of three due to the potentiation of 45 0 C hyperthermia damage by postincubation at 40 0 C. Repair of sublethal radiation damage was completely suppressed during incubation at 40 following hyperthermia at 45 0 C. However, when cells were returned to 37 0 C, even after 6 hr at 40 following 45 0 C hyperthermia, the capacity to accumulate and repair sublethal radiation damage was immediately restored. These findings imply that the hyperthermia damage from low or high temperatures interacts differentially with radiation damage. Low hyperthermia at 40 0 C may affect principally the radiation repair system, whereas 45 0 C hyperthermia probably alters the radiation target more severely than the repair system

Analysis of localized damage in creep rupture

International Nuclear Information System (INIS)

Wang Zhengdong; Wu Dongdi

1992-01-01

Continuum Damage Mechanics studies the effect of distributed defects, whereas the failure of engineering structures is usually caused by local damage. In this paper, an analysis of localized damage in creep rupture is carried out. The material tested is a 2 1/4Cr-1Mo pressure vessel steel and the material constants necessary for damage analysis are evaluated. Notched specimens are used to reflect localized damage in creep rupture and the amount of damage is measured using DCPD method. Through FEM computation, stress components and effective stress in the region of notch root are evaluated and it is found that the von Mises effective stress can represent the damage effective stress in the analysis of localized creep damage. It is possible to develop a method for the assessment of safety of pressure vessels under creep through localized creep damage analysis. (orig.)

Aircraft ground damage and the use of predictive models to estimate costs

Science.gov (United States)

Kromphardt, Benjamin D.

Aircraft are frequently involved in ground damage incidents, and repair costs are often accepted as part of doing business. The Flight Safety Foundation (FSF) estimates ground damage to cost operators $5-10 billion annually. Incident reports, documents from manufacturers or regulatory agencies, and other resources were examined to better understand the problem of ground damage in aviation. Major contributing factors were explained, and two versions of a computer-based model were developed to project costs and show what is possible. One objective was to determine if the models could match the FSF's estimate. Another objective was to better understand cost savings that could be realized by efforts to further mitigate the occurrence of ground incidents. Model effectiveness was limited by access to official data, and assumptions were used if data was not available. However, the models were determined to sufficiently estimate the costs of ground incidents.

Reduction of DNA damage induced by titanium dioxide nanoparticles through Nrf2 in vitro and in vivo

Energy Technology Data Exchange (ETDEWEB)

Shi, Zhiqin [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Department of Laboratory Diagnosis, Hebei Medical University, Shijiazhuang (China); Niu, Yujie [Department of Occupational Health and Environmental Health, Hebei Medical University, Shijiazhuang (China); Wang, Qian [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Shi, Lei [Department of Occupational Health and Environmental Health, Hebei Medical University, Shijiazhuang (China); Guo, Huicai; Liu, Yi; Zhu, Yue [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Liu, Shufeng; Liu, Chao [Hebei Keylab of Laboratory Animal Science, Shijiazhuang (China); Chen, Xin [Xiumen Community Health Service Centre, Shijiazhuang (China); Zhang, Rong, E-mail: rongzhang@hebmu.edu.cn [Department of Toxicology, Hebei Medical University, Shijiazhuang (China); Hebei Keylab of Laboratory Animal Science, Shijiazhuang (China)

2015-11-15

Highlights: • Nrf2 signals were partly responsible for the DNA damage induced by Nano-TiO{sub 2}. • Nrf2 loss could aggravate the DNA damage induced by Nano-TiO{sub 2}. • Acquired Nrf2 decreased the susceptibility to DNA damage induced by Nano-TiO{sub 2}. - Abstract: Titanium dioxide nanoparticles (Nano-TiO{sub 2}) are widely used to additives in cosmetics, pharmaceutical, paints and foods. Recent studies have demonstrated that Nano-TiO{sub 2} induces DNA damage and increased the risk of cancer and the mechanism might relate with oxidative stress. The aim of this study was to evaluate the effects of Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2), an anti-oxidative mediator, on DNA damage induced by Nano-TiO{sub 2}. Wildtype, Nrf2 knockout (Nrf2(-/-)) and tert-butylhydroquinone (tBHQ) pre-treated HepG2 cells and mice were treated with Nano-TiO{sub 2}. And then the oxidative stress and DNA damage were evaluated. Our data showed that DNA damage, reactive oxygen species (ROS) generation and MDA content in Nano-TiO{sub 2} exposed cells were significantly increased than those of control in dose dependent manners. Nrf2/ARE droved the downstream genes including NAD(P)H dehydrogenase [quinine] 1(NQO1), heme oxygenase 1 (HO-1) and glutamate-cysteine ligase catalytic subunit (GCLC) expression were significantly higher in wildtype HepG2 cells after Nano-TiO{sub 2} treatment. After treatment with Nano-TiO{sub 2}, the DNA damages were significantly increased in Nrf(-/-) cells and mice whereas significantly decreased in tBHQ pre-treatment cells and mice, compared with the wildtype HepG2 cells and mice, respectively. Our results indicated that the acquired of Nrf2 leads to a decreased susceptibility to DNA damages induction by Nano-TiO{sub 2} and decreasing of risk of cancer which would provide a strategy for a more efficacious sensitization of against of Nano-TiO{sub 2} toxication.

Mechanisms Underlying Testicular Damage and Dysfunction in Mice With Partial IGF-1 Deficiency and the Effectiveness of IGF-1 Replacement Therapy.

Science.gov (United States)

Castilla-Cortázar, Inma; Gago, Alberto; Muñoz, Úrsula; Ávila-Gallego, Elena; Guerra-Menéndez, Lucía; Sádaba, María Cruz; García-Magariño, Mariano; Olleros Santos-Ruiz, María; Aguirre, G A; Puche, Juan Enrique

2015-12-01

To determine whether insulin-like growth factor (IGF-1) deficiency can cause testicular damage and to examine changes of the testicular morphology and testicular function-related gene expression caused by IGF-1 deficiency. Therefore, this study aims to determine the benefits of low doses of IGF-1 and to explore the mechanisms underlying the IGF-1 replacement therapy. A murine model of IGF-1 deficiency was used to avoid any factor that could contribute to testicular damage. Testicular weight, score of histopathological damage, and gene expressions were studied in 3 experimental groups of mice: controls (wild-type Igf1(+/+)), heterozygous Igf1(+/-) with partial IGF-1 deficiency, and heterozygous Igf1(+/-) treated with IGF-1. Results show that the partial IGF-1 deficiency induced testicular damage and altered expression of genes involved in IGF-1 and growth hormone signaling and regulation, testicular hormonal function, extracellular matrix establishment and its regulation, angiogenesis, fibrogenesis, inflammation, and cytoprotection. In addition, proteins involved in tight junction expression were found to be reduced. However, low doses of IGF-1 restored the testicular damage and most of these parameters. IGF-1 deficiency caused the damage of the blood-testis barrier and testicular structure and induced the abnormal testicular function-related gene expressions. However, low doses of IGF-1 constitute an effective replacement therapy that restores the described testicular damage. Data herein show that (1) cytoprotective activities of IGF-1 seem to be mediated by heat shock proteins and that (2) connective tissue growth factor could play a relevant role together with IGF-1 in the extracellular matrix establishment. Copyright © 2015 Elsevier Inc. All rights reserved.

P2X7 receptor activation ameliorates CA3 neuronal damage via a tumor necrosis factor-α-mediated pathway in the rat hippocampus following status epilepticus

Directory of Open Access Journals (Sweden)

Ryu Hea Jin

2011-06-01

Full Text Available Abstract Background The release of tumor necrosis factor-α (TNF-α appears depend on the P2X7 receptor, a purinergic receptor. In the present study, we addressed the question of whether P2X7 receptor-mediated TNF-α regulation is involved in pathogenesis and outcome of status epilepticus (SE. Methods SE was induced by pilocarpine in rats that were intracerebroventricularly infused with saline-, 2',3'-O-(4-benzoylbenzoyl-adenosine 5'-triphosphate (BzATP, adenosine 5'-triphosphate-2',3'-dialdehyde (OxATP, A-438079, or A-740003 prior to SE induction. Thereafter, we performed Fluoro-Jade B staining and immunohistochemical studies for TNF-α and NF-κB subunit phosphorylations. Results Following SE, P2X7 receptor agonist (BzATP infusion increased TNF-α immunoreactivity in dentate granule cells as compared with that in saline-infused animals. In addition, TNF-α immunoreactivity was readily apparent in the mossy fibers, while TNF-α immunoreactivity in CA1-3 pyramidal cells was unaltered. However, P2X7 receptor antagonist (OxATP-, A-438079, and A-740003 infusion reduced SE-induced TNF-α expression in dentate granule cells. In the CA3 region, BzATP infusion attenuated SE-induced neuronal damage, accompanied by enhancement of p65-Ser276 and p65-Ser311 NF-κB subunit phosphorylations. In contrast, OxATP-, A-438079, and A-740003 infusions increased SE-induced neuronal death. Soluble TNF p55 receptor (sTNFp55R, and cotreatment with BzATP and sTNFp55R infusion also increased SE-induced neuronal damage in CA3 region. However, OxATP-, sTNFp55R or BzATP+sTNFp55R infusions could not exacerbate SE-induced neuronal damages in the dentate gyrus and the CA1 region, as compared to BzATP infusion. Conclusions These findings suggest that TNF-α induction by P2X7 receptor activation may ameliorate SE-induced CA3 neuronal damage via enhancing NF-κB p65-Ser276 and p65-Ser311 phosphorylations.

Laser damage metrology in biaxial nonlinear crystals using different test beams

Science.gov (United States)

Hildenbrand, Anne; Wagner, Frank R.; Akhouayri, Hassan; Natoli, Jean-Yves; Commandre, Mireille

2008-01-01

Laser damage measurements in nonlinear optical crystals, in particular in biaxial crystals, may be influenced by several effects proper to these materials or greatly enhanced in these materials. Before discussion of these effects, we address the topic of error bar determination for probability measurements. Error bars for the damage probabilities are important because nonlinear crystals are often small and expensive, thus only few sites are used for a single damage probability measurement. We present the mathematical basics and a flow diagram for the numerical calculation of error bars for probability measurements that correspond to a chosen confidence level. Effects that possibly modify the maximum intensity in a biaxial nonlinear crystal are: focusing aberration, walk-off and self-focusing. Depending on focusing conditions, propagation direction, polarization of the light and the position of the focus point in the crystal, strong aberrations may change the beam profile and drastically decrease the maximum intensity in the crystal. A correction factor for this effect is proposed, but quantitative corrections are not possible without taking into account the experimental beam profile after the focusing lens. The characteristics of walk-off and self-focusing have quickly been reviewed for the sake of completeness of this article. Finally, parasitic second harmonic generation may influence the laser damage behavior of crystals. The important point for laser damage measurements is that the amount of externally observed SHG after the crystal does not correspond to the maximum amount of second harmonic light inside the crystal.

Damage in the Multiethnic Malaysian Systemic Lupus Erythematosus (SLE) Cohort: Comparison with Other Cohorts Worldwide

Science.gov (United States)

Shaharir, Syahrul Sazliyana; Hussein, Heselynn; Rajalingham, Sakthiswary; Mohamed Said, Mohd Shahrir; Abdul Gafor, Abdul Halim; Mohd, Rozita; Mustafar, Ruslinda

2016-01-01

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease and despite the improvement in the survival in the past few decades, the morbidity due to disease damage remains significant. The objectives of this study were to investigate the disease damagepattern and determine the associated factors of damage in the multi-ethnic Malaysian SLE patients. We consecutively 424SLE patients who attended a consistent follow-up at the National University of Malaysia Medical Centre and Putrajaya Hospital were recruited. Disease damage was assessed using the SLICC/ACR (Systemic Lupus International Collaborating Clinics/American College of Rheumatology) Damage Index (SDI) scores. Information on their demographics and disease characteristics were obtained from the clinical record. Univariate analysis was performed and the best model of independent predictors of disease damage was determined by multivariate logistic regression analysis. A total of 182 patients (42.9%) had disease damage (SDI ≥1). A significantly higher number of Indian patients had disease/organ damage and they predominantly developed steroid-induced diabetes mellitus (SDM). Patients with corticosteroid-induced osteoporosis (CIOP) were more likely to be Malayswhile majority of patients who developed malignancy were Chinese (p<0.05). In the univariate and multivariate analyses, disease damage was significantly associated with age, Indian ethnicity, lower mean cumulative C3 level, neuropsychiatry lupus (NPSLE), and antiphospholipid syndrome (APLS). Patients who had ever and early treatment with hydroxychloroquine(HCQ)were less likely to develop disease damage while more patients who had received oral prednisolone ≥1mg/kg daily over 2 weeks had disease damage (p<0.05). In conclusion, there were inter-ethnic differences in the damage pattern and risks among SLE patients. PMID:27846298

Radiation damage in semiconductor detectors

International Nuclear Information System (INIS)

Kraner, H.W.

1981-12-01

A survey is presented of the important damage-producing interactions in semiconductor detectors and estimates of defect numbers are made for MeV protons, neutrons and electrons. Damage effects of fast neutrons in germanium gamma ray spectrometers are given in some detail. General effects in silicon detectors are discussed and damage constants and their relationship to leakage current is introduced

Proteomic investigations reveal a role for RNA processing factor THRAP3 in the DNA damage response

DEFF Research Database (Denmark)

Beli, Petra; Lukashchuk, Natalia; Wagner, Sebastian A

2012-01-01

/ATR/DNA-PK target consensus motif, suggesting an important role of downstream kinases in amplifying DDR signals. We show that the splicing-regulator phosphatase PPM1G is recruited to sites of DNA damage, while the splicing-associated protein THRAP3 is excluded from these regions. Moreover, THRAP3 depletion causes...

Low cycle fatigue: high cycle fatigue damage accumulation in a 304L austenitic stainless steel

International Nuclear Information System (INIS)

Lehericy, Y.

2007-05-01

The aim of this study was to evaluate the consequences of a Low Cycle Fatigue pre-damage on the subsequent fatigue limit of a 304L stainless steel. The effects of hardening and severe roughness (grinding) have also been investigated. In a first set of tests, the evolution of the surface damage induced by the different LCF pre-cycling was characterized. This has permitted to identify mechanisms and kinetics of damage in the plastic domain for different surface conditions. Then, pre-damaged samples were tested in the High Cycle Fatigue domain in order to establish the fatigue limits associated with each level of pre-damage. Results evidence that, in the case of polished samples, an important number of cycles is required to initiate surface cracks ant then to affect the fatigue limit of the material but, in the case of ground samples, a few number of cycles is sufficient to initiate cracks and to critically decrease the fatigue limit. The fatigue limit of pre-damaged samples can be estimated using the stress intensity factor threshold. Moreover, this detrimental effect of severe surface conditions is enhanced when fatigue tests are performed under a positive mean stress (author)

DNA-damage response associated with occupational exposure, age and chronic inflammation in workers in the automotive industry.

Science.gov (United States)

Savina, Natalya V; Smal, Marharyta P; Kuzhir, Tatyana D; Ershova-Pavlova, Alla A; Goncharova, Roza I

2012-10-09

The evaluation of genome integrity in populations occupationally exposed to combine industrial factors is of medical importance. In the present study, the DNA-damage response was estimated by means of the alkaline comet assay in a sizeable cohort of volunteers recruited among workers in the automotive industry. For this purpose, freshly collected lymphocytes were treated with hydrogen peroxide (100μM, 1min, 4°C) in vitro, and the levels of basal and H(2)O(2)-induced DNA damage, and the kinetics and efficiency of DNA repair were measured during a 180-min interval after exposure. The parameters studied in the total cohort of workers were in a range of values prescribed for healthy adult residents of Belarus. Based on the 95th percentiles, individuals possessing enhanced cellular sensitivity to DNA damage were present in different groups, but the frequency was significantly higher among elderly persons and among individuals with chronic inflammatory diseases. The results indicate that the inter-individual variations in DNA-damage response should be taken into account to estimate adequately the environmental genotoxic effects and to identify individuals with an enhanced DNA-damage response due to the influence of some external factors or intrinsic properties of the organism. Underling mechanisms need to be further explored. © 2012 Elsevier B.V. All rights reserved.

Pearlitic ductile cast iron: damaging micromechanisms at crack tip

Directory of Open Access Journals (Sweden)

F. Iacoviello

2013-07-01

Full Text Available Ductile cast irons (DCIs are characterized by a wide range of mechanical properties, mainly depending on microstructural factors, as matrix microstructure (characterized by phases volume fraction, grains size and grain distribution, graphite nodules (characterized by size, shape, density and distribution and defects presence (e.g., porosity, inclusions, etc.. Versatility and higher performances at lower cost if compared to steels with analogous performances are the main DCIs advantages. In the last years, the role played by graphite nodules was deeply investigated by means of tensile and fatigue tests, performing scanning electron microscope (SEM observations of specimens lateral surfaces during the tests (“in situ” tests and identifying different damaging micromechanisms.In this work, a pearlitic DCIs fatigue resistance is investigated considering both fatigue crack propagation (by means of Compact Type specimens and according to ASTM E399 standard and overload effects, focusing the interaction between the crack and the investigated DCI microstructure (pearlitic matrix and graphite nodules. On the basis of experimental results, and considering loading conditions and damaging micromechanisms, the applicability of ASTM E399 standard on the characterization of fatigue crack propagation resistance in ferritic DCIs is critically analyzed, mainly focusing the stress intensity factor amplitude role.

Effective elastic properties of damaged isotropic solids

International Nuclear Information System (INIS)

Lee, U Sik

1998-01-01

In continuum damage mechanics, damaged solids have been represented by the effective elastic stiffness into which local damage is smoothly smeared. Similarly, damaged solids may be represented in terms of effective elastic compliances. By virtue of the effective elastic compliance representation, it may become easier to derive the effective engineering constants of damaged solids from the effective elastic compliances, all in closed form. Thus, in this paper, by using a continuum modeling approach based on both the principle of strain energy equivalence and the equivalent elliptical micro-crack representation of local damage, the effective elastic compliance and effective engineering constants are derived in terms of the undamaged (virgin) elastic properties and a scalar damage variable for both damaged two-and three-dimensional isotropic solids

A broader classification of damage zones

Science.gov (United States)

Peacock, D. C. P.; Dimmen, V.; Rotevatn, A.; Sanderson, D. J.

2017-09-01

Damage zones have previously been classified in terms of their positions at fault tips, walls or areas of linkage, with the latter being described in terms of sub-parallel and synchronously active faults. We broaden the idea of linkage to include structures around the intersections of non-parallel and/or non-synchronous faults. These interaction damage zones can be divided into approaching damage zones, where the faults kinematically interact but are not physically connected, and intersection damage zones, where the faults either abut or cross-cut. The damage zone concept is applied to other settings in which strain or displacement variations are taken up by a range of structures, such as at fault bends. It is recommended that a prefix can be added to a wide range of damage zones, to describe the locations in which they formed, e.g., approaching, intersection and fault bend damage zone. Such interpretations are commonly based on limited knowledge of the 3D geometries of the structures, such as from exposure surfaces, and there may be spatial variations. For example, approaching faults and related damage seen in outcrop may be intersecting elsewhere on the fault planes. Dilation in intersection damage zones can represent narrow and localised channels for fluid flow, and such dilation can be influenced by post-faulting stress patterns.

Radiation damage to mushrooms

International Nuclear Information System (INIS)

Sattler, P.W.

1986-01-01

This document contains newspaper cuttings and correspondence with various ministries in Hessen on the subject of radiation damage to mushrooms from the Odenwald area. The reader is given, amongst other things, detailed information on radiation damage to different types of mushroom in 1986. (MG) [de

Evaluation of creep damage development by the replica method; Utvaerdering av krypskadeutveckling med replikmetoden

Energy Technology Data Exchange (ETDEWEB)

Storesund, Jan [Det Norske Veritas AB, Stockholm (Sweden); Roennholm, Markku [Fortum (Sweden)

2002-04-01

Creep damage development in high temperature components can be monitored by the replica method. Damage is classified and an experience based time period for safe operation is recommended where a re-inspection should be conducted. Original recommendations are still commonly used but there are also developed ones are mostly less conservative. A data base of more than 6000 replicas, collected from welded components in Swedish and Finnish power plants, has been evaluated with respect to damage development in the present project. The results are in general in good agreement to the existing developed recommendations for re-inspections. Important factors that should be considered for use of the recommendations are highlighted: Service history, Material, welding and heat treatment, Measure of pressure and temperature, System stresses, Geometrical stress concentrations, stress distributions, Design of components and welds, Creep crack growth, Starts and stops, Extent and performance of the replica method. These factors have been analysed with respect to the evaluated data resulting in comments to the existing recommendations. In addition, recommendations and conditions for a high reliability of the replica method are described. The comments and recommendations can be read in separate sections in the end of the report.

Damaging Rainfall and Flooding. The Other Sahel Hazards

Energy Technology Data Exchange (ETDEWEB)

Tarhule, A. [Department of Geography, University of Oklahoma, 100 East Boyd Street, Norman, OK, 73079 (United States)

2005-10-01

Damaging rainfall and rain-induced flooding occur from time to time in the drought-prone Sahel savannah zone of Niger in West Africa but official records of these events and their socioeconomic impacts do not exist. This paper utilized newspaper accounts between 1970 and 2000 to survey and illustrate the range of these flood hazards in the Sahel. During the study interval, 53 newspaper articles reported 79 damaging rainfall and flood events in 47 different communities in the Sahel of Niger. Collectively, these events destroyed 5,580 houses and rendered 27,289 people homeless. Cash losses and damage to infrastructure in only three events exceeded $4 million. Sahel residents attribute these floods to five major causes including both natural and anthropogenic, but they view the flood problem as driven primarily by land use patterns. Despite such awareness, traditional coping strategies appear inadequate for dealing with the problems in part because of significant climatic variability. Analysis of several rainfall measures indicates that the cumulative rainfall in the days prior to a heavy rain event is an important factor influencing whether or not heavy rainfall results in flooding. Thus, despite some limitations, newspaper accounts of historical flooding are largely consistent with measured climatic variables. The study demonstrates that concerted effort is needed to improve the status of knowledge concerning flood impacts and indeed other natural and human hazards in the Sahel.

Increased effects of machining damage in beryllium observed at high strain rates

International Nuclear Information System (INIS)

Beitscher, S.; Brewer, A.W.; Corle, R.R.

1980-01-01

Tensile tests at both low and high strain rates, and also impact shear tests, were performed on a weldable grade powder-source beryllium. Impact energies increased by a factor of 2 to 3 from the as-machined level after etching or annealing. Similar increases in the ductility from machining damage removal were observed from the tensile data at the higher strain rate (10 s -1 ) while an insignificant increase in elongation was measured at the lower strain rate (10 -4 s -1 ). High strain-rate tests appear to be more sensitive and reliable for evaluating machining practice and damage removal methods for beryllium components subjected to sudden loads. 2 tables

Mechanism of metformin action in MCF-7 and MDA-MB-231 human breast cancer cells involves oxidative stress generation, DNA damage, and transforming growth factor β1 induction.

Science.gov (United States)

Marinello, Poliana Camila; da Silva, Thamara Nishida Xavier; Panis, Carolina; Neves, Amanda Fouto; Machado, Kaliana Larissa; Borges, Fernando Henrique; Guarnier, Flávia Alessandra; Bernardes, Sara Santos; de-Freitas-Junior, Júlio Cesar Madureira; Morgado-Díaz, José Andrés; Luiz, Rodrigo Cabral; Cecchini, Rubens; Cecchini, Alessandra Lourenço

2016-04-01

The participation of oxidative stress in the mechanism of metformin action in breast cancer remains unclear. We investigated the effects of clinical (6 and 30 μM) and experimental concentrations of metformin (1000 and 5000 μM) in MCF-7 and in MDA-MB-231 cells, verifying cytotoxicity, oxidative stress, DNA damage, and intracellular pathways related to cell growth and survival after 24 h of drug exposure. Clinical concentrations of metformin decreased metabolic activity of MCF-7 cells in the MTT assay, which showed increased oxidative stress and DNA damage, although cell death and impairment in the proliferative capacity were observed only at higher concentrations. The reduction in metabolic activity and proliferation in MDA-MB-231 cells was present only at experimental concentrations after 24 h of drug exposition. Oxidative stress and DNA damage were induced in this cell line at experimental concentrations. The drug decreased cytoplasmic extracellular signal-regulated kinases 1 and 2 (ERK1/2) and AKT and increased nuclear p53 and cytoplasmic transforming growth factor β1 (TGF-β1) in both cell lines. These findings suggest that metformin reduces cell survival by increasing reactive oxygen species, which induce DNA damage and apoptosis. A relationship between the increase in TGF-β1 and p53 levels and the decrease in ERK1/2 and AKT was also observed. These findings suggest the mechanism of action of metformin in both breast cancer cell lineages, whereas cell line specific undergoes redox changes in the cells in which proliferation and survival signaling are modified. Taken together, these results highlight the potential clinical utility of metformin as an adjuvant during the treatment of luminal and triple-negative breast cancer.

Computational micromechanics analysis of electron hopping and interfacial damage induced piezoresistive response in carbon nanotube-polymer nanocomposites

International Nuclear Information System (INIS)

Chaurasia, A K; Seidel, G D; Ren, X

2014-01-01

Carbon nanotube (CNT)-polymer nanocomposites have been observed to exhibit an effective macroscale piezoresistive response, i.e., change in macroscale resistivity when subjected to applied deformation. The macroscale piezoresistive response of CNT-polymer nanocomposites leads to deformation/strain sensing capabilities. It is believed that the nanoscale phenomenon of electron hopping is the major driving force behind the observed macroscale piezoresistivity of such nanocomposites. Additionally, CNT-polymer nanocomposites provide damage sensing capabilities because of local changes in electron hopping pathways at the nanoscale because of initiation/evolution of damage. The primary focus of the current work is to explore the effect of interfacial separation and damage at the nanoscale CNT-polymer interface on the effective macroscale piezoresistive response. Interfacial separation and damage are allowed to evolve at the CNT-polymer interface through coupled electromechanical cohesive zones, within a finite element based computational micromechanics framework, resulting in electron hopping based current density across the separated CNT-polymer interface. The macroscale effective material properties and gauge factors are evaluated using micromechanics techniques based on electrostatic energy equivalence. The impact of the electron hopping mechanism, nanoscale interface separation and damage evolution on the effective nanocomposite electrostatic and piezoresistive response is studied in comparison with the perfectly bonded interface. The effective electrostatic/piezoresistive response for the perfectly bonded interface is obtained based on a computational micromechanics model developed in the authors’ earlier work. It is observed that the macroscale effective gauge factors are highly sensitive to strain induced formation/disruption of electron hopping pathways, interface separation and the initiation/evolution of interfacial damage. (paper)

Recruitment of RNA polymerase II cofactor PC4 to DNA damage sites

Science.gov (United States)

Mortusewicz, Oliver; Roth, Wera; Li, Na; Cardoso, M. Cristina; Meisterernst, Michael; Leonhardt, Heinrich

2008-01-01

The multifunctional nuclear protein positive cofactor 4 (PC4) is involved in various cellular processes including transcription, replication, and chromatin organization. Recently, PC4 has been identified as a suppressor of oxidative mutagenesis in Escherichia coli and Saccharomyces cerevisiae. To investigate a potential role of PC4 in mammalian DNA repair, we used a combination of live cell microscopy, microirradiation, and fluorescence recovery after photobleaching analysis. We found a clear accumulation of endogenous PC4 at DNA damage sites introduced by either chemical agents or laser microirradiation. Using fluorescent fusion proteins and specific mutants, we demonstrated that the rapid recruitment of PC4 to laser-induced DNA damage sites is independent of poly(ADP-ribosyl)ation and γH2AX but depends on its single strand binding capacity. Furthermore, PC4 showed a high turnover at DNA damages sites compared with the repair factors replication protein A and proliferating cell nuclear antigen. We propose that PC4 plays a role in the early response to DNA damage by recognizing single-stranded DNA and may thus initiate or facilitate the subsequent steps of DNA repair. PMID:19047459

Rho GTPases: Novel Players in the Regulation of the DNA Damage Response?

Directory of Open Access Journals (Sweden)

Gerhard Fritz

2015-09-01

Full Text Available The Ras-related C3 botulinum toxin substrate 1 (Rac1 belongs to the family of Ras-homologous small GTPases. It is well characterized as a membrane-bound signal transducing molecule that is involved in the regulation of cell motility and adhesion as well as cell cycle progression, mitosis, cell death and gene expression. Rac1 also adjusts cellular responses to genotoxic stress by regulating the activity of stress kinases, including c-Jun-N-terminal kinase/stress-activated protein kinase (JNK/SAPK and p38 kinases as well as related transcription factors. Apart from being found on the inner side of the outer cell membrane and in the cytosol, Rac1 has also been detected inside the nucleus. Different lines of evidence indicate that genotoxin-induced DNA damage is able to activate nuclear Rac1. The exact mechanisms involved and the biological consequences, however, are unclear. The data available so far indicate that Rac1 might integrate DNA damage independent and DNA damage dependent cellular stress responses following genotoxin treatment, thereby coordinating mechanisms of the DNA damage response (DDR that are related to DNA repair, survival and cell death.

Flood damage curves for consistent global risk assessments

Science.gov (United States)

de Moel, Hans; Huizinga, Jan; Szewczyk, Wojtek

2016-04-01

Assessing potential damage of flood events is an important component in flood risk management. Determining direct flood damage is commonly done using depth-damage curves, which denote the flood damage that would occur at specific water depths per asset or land-use class. Many countries around the world have developed flood damage models using such curves which are based on analysis of past flood events and/or on expert judgement. However, such damage curves are not available for all regions, which hampers damage assessments in those regions. Moreover, due to different methodologies employed for various damage models in different countries, damage assessments cannot be directly compared with each other, obstructing also supra-national flood damage assessments. To address these problems, a globally consistent dataset of depth-damage curves has been developed. This dataset contains damage curves depicting percent of damage as a function of water depth as well as maximum damage values for a variety of assets and land use classes (i.e. residential, commercial, agriculture). Based on an extensive literature survey concave damage curves have been developed for each continent, while differentiation in flood damage between countries is established by determining maximum damage values at the country scale. These maximum damage values are based on construction cost surveys from multinational construction companies, which provide a coherent set of detailed building cost data across dozens of countries. A consistent set of maximum flood damage values for all countries was computed using statistical regressions with socio-economic World Development Indicators from the World Bank. Further, based on insights from the literature survey, guidance is also given on how the damage curves and maximum damage values can be adjusted for specific local circumstances, such as urban vs. rural locations, use of specific building material, etc. This dataset can be used for consistent supra

Regulation of DNA Alkylation Damage Repair: Lessons and Therapeutic Opportunities.

Science.gov (United States)

Soll, Jennifer M; Sobol, Robert W; Mosammaparast, Nima

2017-03-01

Alkylation chemotherapy is one of the most widely used systemic therapies for cancer. While somewhat effective, clinical responses and toxicities of these agents are highly variable. A major contributing factor for this variability is the numerous distinct lesions that are created upon alkylation damage. These adducts activate multiple repair pathways. There is mounting evidence that the individual pathways function cooperatively, suggesting that coordinated regulation of alkylation repair is critical to prevent toxicity. Furthermore, some alkylating agents produce adducts that overlap with newly discovered methylation marks, making it difficult to distinguish between bona fide damaged bases and so-called 'epigenetic' adducts. Here, we discuss new efforts aimed at deciphering the mechanisms that regulate these repair pathways, emphasizing their implications for cancer chemotherapy. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Progressive Damage Model for Predicting Permanent Indentation and Impact Damage in Composite Laminates

Science.gov (United States)

Ji, Zhaojie; Guan, Zhidong; Li, Zengshan

2017-10-01

In this paper, a progressive damage model was established on the basis of ABAQUS software for predicting permanent indentation and impact damage in composite laminates. Intralaminar and interlaminar damage was modelled based on the continuum damage mechanics (CDM) in the finite element model. For the verification of the model, low-velocity impact tests of quasi-isotropic laminates with material system of T300/5228A were conducted. Permanent indentation and impact damage of the laminates were simulated and the numerical results agree well with the experiments. It can be concluded that an obvious knee point can be identified on the curve of the indentation depth versus impact energy. Matrix cracking and delamination develops rapidly with the increasing impact energy, while considerable amount of fiber breakage only occurs when the impact energy exceeds the energy corresponding to the knee point. Predicted indentation depth after the knee point is very sensitive to the parameter μ which is proposed in this paper, and the acceptable value of this parameter is in range from 0.9 to 1.0.

Uncertainty Evaluation in the Design of Structural Health Monitoring Systems for Damage Detection†

Directory of Open Access Journals (Sweden)

Christine Schubert Kabban

2018-04-01

Full Text Available The validation of structural health monitoring (SHM systems for aircraft is complicated by the extent and number of factors that the SHM system must demonstrate for robust performance. Therefore, a time- and cost-efficient method for examining all of the sensitive factors must be conducted. In this paper, we demonstrate the utility of using the simulation modeling environment to determine the SHM sensitive factors that must be considered for subsequent experiments, in order to enable the SHM validation. We demonstrate this concept by examining the effect of SHM system configuration and flaw characteristics on the response of a signal from a known piezoelectric wafer active sensor (PWAS in an aluminum plate, using simulation models of a particular hot spot. We derive the signal responses mathematically and through the statistical design of experiments, we determine the significant factors that affect the damage indices that are computed from the signal, using only half the number of runs that are normally required. We determine that the transmitter angle is the largest source of variation for the damage indices that are considered, followed by signal frequency and transmitter distance to the hot spot. These results demonstrate that the use of efficient statistical design and simulation may enable a cost- and time-efficient sequential approach to quantifying sensitive SHM factors and system validation.

RUNX Family Participates in the Regulation of p53-Dependent DNA Damage Response

Directory of Open Access Journals (Sweden)

Toshinori Ozaki

2013-01-01

Full Text Available A proper DNA damage response (DDR, which monitors and maintains the genomic integrity, has been considered to be a critical barrier against genetic alterations to prevent tumor initiation and progression. The representative tumor suppressor p53 plays an important role in the regulation of DNA damage response. When cells receive DNA damage, p53 is quickly activated and induces cell cycle arrest and/or apoptotic cell death through transactivating its target genes implicated in the promotion of cell cycle arrest and/or apoptotic cell death such as p21WAF1, BAX, and PUMA. Accumulating evidence strongly suggests that DNA damage-mediated activation as well as induction of p53 is regulated by posttranslational modifications and also by protein-protein interaction. Loss of p53 activity confers growth advantage and ensures survival in cancer cells by inhibiting apoptotic response required for tumor suppression. RUNX family, which is composed of RUNX1, RUNX2, and RUNX3, is a sequence-specific transcription factor and is closely involved in a variety of cellular processes including development, differentiation, and/or tumorigenesis. In this review, we describe a background of p53 and a functional collaboration between p53 and RUNX family in response to DNA damage.

Selective activation of human heat shock gene transcription by nitrosourea antitumor drugs mediated by isocyanate-induced damage and activation of heat shock transcription factor.

Science.gov (United States)

Kroes, R A; Abravaya, K; Seidenfeld, J; Morimoto, R I

1991-01-01

Treatment of cultured human tumor cells with the chloroethylnitrosourea antitumor drug 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) selectively induces transcription and protein synthesis of a subset of the human heat shock or stress-induced genes (HSP90 and HSP70) with little effect on other stress genes or on expression of the c-fos, c-myc, or beta-actin genes. The active component of BCNU and related compounds appears to be the isocyanate moiety that causes carbamoylation of proteins and nucleic acids. Transcriptional activation of the human HSP70 gene by BCNU is dependent on the heat shock element and correlates with the level of heat shock transcription factor and its binding to the heat shock element in vivo. Unlike activation by heat or heavy metals, BCNU-mediated activation is strongly dependent upon new protein synthesis. This suggests that BCNU-induced, isocyanate-mediated damage to newly synthesized protein(s) may be responsible for activation of the heat shock transcription factor and increased transcription of the HSP90 and HSP70 genes. Images PMID:2052560

Contribution of endogenous and exogenous damage to the total radiation-induced damage in the bacterial spore

International Nuclear Information System (INIS)

Jacobs, G.P.; Samuni, A.; Czapski, G.

1980-01-01

Radical scavengers such as polyethylene glycol 4000 and bovine albumin have been used to define the contribution of exogenous and endogenous damage to the total radiation-induced damage in aqueous buffered suspensions of Bacillus pumilus spores. The results indicate that this damage in the bacterial spore is predominantly endogenous

Can radiation damage to protein crystals be reduced using small-molecule compounds?

Energy Technology Data Exchange (ETDEWEB)

Kmetko, Jan [Kenyon College, Gambier, OH 43022 (United States); Warkentin, Matthew; Englich, Ulrich; Thorne, Robert E., E-mail: ret6@cornell.edu [Cornell University, Ithaca, NY 14853 (United States); Kenyon College, Gambier, OH 43022 (United States)

2011-10-01

Free-radical scavengers that are known to be effective protectors of proteins in solution are found to increase global radiation damage to protein crystals. Protective mechanisms may become deleterious in the protein-dense environment of a crystal. Recent studies have defined a data-collection protocol and a metric that provide a robust measure of global radiation damage to protein crystals. Using this protocol and metric, 19 small-molecule compounds (introduced either by cocrystallization or soaking) were evaluated for their ability to protect lysozyme crystals from radiation damage. The compounds were selected based upon their ability to interact with radiolytic products (e.g. hydrated electrons, hydrogen, hydroxyl and perhydroxyl radicals) and/or their efficacy in protecting biological molecules from radiation damage in dilute aqueous solutions. At room temperature, 12 compounds had no effect and six had a sensitizing effect on global damage. Only one compound, sodium nitrate, appeared to extend crystal lifetimes, but not in all proteins and only by a factor of two or less. No compound provided protection at T = 100 K. Scavengers are ineffective in protecting protein crystals from global damage because a large fraction of primary X-ray-induced excitations are generated in and/or directly attack the protein and because the ratio of scavenger molecules to protein molecules is too small to provide appreciable competitive protection. The same reactivity that makes some scavengers effective radioprotectors in protein solutions may explain their sensitizing effect in the protein-dense environment of a crystal. A more productive focus for future efforts may be to identify and eliminate sensitizing compounds from crystallization solutions.

Can radiation damage to protein crystals be reduced using small-molecule compounds?

International Nuclear Information System (INIS)

Kmetko, Jan; Warkentin, Matthew; Englich, Ulrich; Thorne, Robert E.

2011-01-01

Free-radical scavengers that are known to be effective protectors of proteins in solution are found to increase global radiation damage to protein crystals. Protective mechanisms may become deleterious in the protein-dense environment of a crystal. Recent studies have defined a data-collection protocol and a metric that provide a robust measure of global radiation damage to protein crystals. Using this protocol and metric, 19 small-molecule compounds (introduced either by cocrystallization or soaking) were evaluated for their ability to protect lysozyme crystals from radiation damage. The compounds were selected based upon their ability to interact with radiolytic products (e.g. hydrated electrons, hydrogen, hydroxyl and perhydroxyl radicals) and/or their efficacy in protecting biological molecules from radiation damage in dilute aqueous solutions. At room temperature, 12 compounds had no effect and six had a sensitizing effect on global damage. Only one compound, sodium nitrate, appeared to extend crystal lifetimes, but not in all proteins and only by a factor of two or less. No compound provided protection at T = 100 K. Scavengers are ineffective in protecting protein crystals from global damage because a large fraction of primary X-ray-induced excitations are generated in and/or directly attack the protein and because the ratio of scavenger molecules to protein molecules is too small to provide appreciable competitive protection. The same reactivity that makes some scavengers effective radioprotectors in protein solutions may explain their sensitizing effect in the protein-dense environment of a crystal. A more productive focus for future efforts may be to identify and eliminate sensitizing compounds from crystallization solutions

Detection of insect damage in almonds

Science.gov (United States)

Kim, Soowon; Schatzki, Thomas F.

1999-01-01

Pinhole insect damage in natural almonds is very difficult to detect on-line. Further, evidence exists relating insect damage to aflatoxin contamination. Hence, for quality and health reasons, methods to detect and remove such damaged nuts are of great importance in this study, we explored the possibility of using x-ray imaging to detect pinhole damage in almonds by insects. X-ray film images of about 2000 almonds and x-ray linescan images of only 522 pinhole damaged almonds were obtained. The pinhole damaged region appeared slightly darker than non-damaged region in x-ray negative images. A machine recognition algorithm was developed to detect these darker regions. The algorithm used the first order and the second order information to identify the damaged region. To reduce the possibility of false positive results due to germ region in high resolution images, germ detection and removal routines were also included. With film images, the algorithm showed approximately an 81 percent correct recognition ratio with only 1 percent false positives whereas line scan images correctly recognized 65 percent of pinholes with about 9 percent false positives. The algorithms was very fast and efficient requiring only minimal computation time. If implemented on line, theoretical throughput of this recognition system would be 66 nuts/second.

Ecological impacts and damage - comparison of selected components for nuclear and conventional power plants (example of Mochovce nuclear power plant)

International Nuclear Information System (INIS)

Bucek, M.

1984-01-01

A comparison is given of ecological damage for the nuclear power plant in Mochovce and a conventional power plant with the same power. Ecological effects and damage are divided into three groups: comparable damage, ecological damage caused only by conventional power plants and ecological damage caused only by nuclear power plants. In the first group the factors compared are land requisition, consumption of utility water and air consumption. In the second group are enumerated losses of crops (cereals, sugar beet, potatoes, oleaginous plants) and losses caused by increased disease rate owing to polluted environment by conventional power plants. In the third group health hazards are assessed linked with ionizing radiation. Also considered are vent stack escapes. (E.S.)

Damage growth in aerospace composites

CERN Document Server

2015-01-01

This book presents novel methods for the simulation of damage evolution in aerospace composites that will assist in predicting damage onset and growth and thus foster less conservative designs which realize the promised economic benefits of composite materials. The presented integrated numerical/experimental methodologies are capable of taking into account the presence of damage and its evolution in composite structures from the early phases of the design (conceptual design) through to the detailed finite element method analysis and verification phase. The book is based on the GARTEUR Research Project AG-32, which ran from 2007 to 2012, and documents the main results of that project. In addition, the state of the art in European projects on damage evolution in composites is reviewed. While the high specific strength and stiffness of composite materials make them suitable for aerospace structures, their sensitivity to damage means that designing with composites is a challenging task. The new approaches describ...

[Pulse-modulated Electromagnetic Radiation of Extremely High Frequencies Protects Cellular DNA against Damaging Effect of Physico-Chemical Factors in vitro].

Science.gov (United States)

Gapeyev, A B; Lukyanova, N A

2015-01-01

Using a comet assay technique, we investigated protective effects of. extremely high frequency electromagnetic radiation in combination with the damaging effect of X-ray irradiation, the effect of damaging agents hydrogen peroxide and methyl methanesulfonate on DNA in mouse whole blood leukocytes. It was shown that the preliminary exposure of the cells to low intensity pulse-modulated electromagnetic radiation (42.2 GHz, 0.1 mW/cm2, 20-min exposure, modulation frequencies of 1 and 16 Hz) caused protective effects decreasing the DNA damage by 20-45%. The efficacy of pulse-modulated electromagnetic radiation depended on the type of genotoxic agent and increased in a row methyl methanesulfonate--X-rays--hydrogen peroxide. Continuous electromagnetic radiation was ineffective. The mechanisms of protective effects may be connected with an induction of the adaptive response by nanomolar concentrations of reactive oxygen species formed by pulse-modulated electromagnetic radiation.

Economic valuation of acidic deposition damages: Preliminary results from the 1985 NAPAP [National Acid Precipitation Assessment Program] damage assessment

International Nuclear Information System (INIS)

Callaway, J.M.; Darwin, R.F.; Nesse, R.J.

1985-01-01

This paper identifies methods used to evaluate the economic damages of acid deposition in the 1985 Damage Assessment being coordinated by the National Acid Precipitation Program. It also presents the preliminary estimates of economic damages for the Assessment. Economic damages are estimated for four effect areas: commercial agriculture and forests, recreational fishing and selected types of materials. In all but the last area, methods are used which incorporate the behavioral responses of individuals and firms or simulated physical damages to resources at risk. The preliminary nature of the estimated damages in each area is emphasized. Over all, the damage estimates should be interpreted with caution. 44 refs., 6 figs., 5 tabs

Liability for damage to the global commons

International Nuclear Information System (INIS)

Leigh, K.

1993-01-01

The 'global commons' discussed in this paper are the areas beyond the limits of national jurisdiction. Responsibility to prevent environmental damage to these areas is clearly recognized in customary international law. On the other hand, although liability for such damage undoubtedly has a useful role to play in protecting these areas, the precise nature of liability for such damage is unclear. Some issues, such as whether liability for such damage is strict or tied to breaching a standard of care and the definition of environmental damage, equally arise in relation to damage to the environment of States. Others, such as who could take action to enforce the liability and the nature of the remedy, raise special problems in the case of damage to the global commons. The work under way in the IAEA Standing Committee on Liability for Nuclear Damage provides an opportunity for clarifying these issues in relation to nuclear damage to the global commons. Treaties dealing with particular types of damage which have recently been adopted or are currently being developed in other fields provide a starting point in dealing with this matter. More work, however, needs to be done

The NBS1-Treacle complex controls ribosomal RNA transcription in response to DNA damage

DEFF Research Database (Denmark)

Larsen, Dorthe H; Hari, Flurina; Clapperton, Julie A

2014-01-01

Chromosome breakage elicits transient silencing of ribosomal RNA synthesis, but the mechanisms involved remained elusive. Here we discover an in trans signalling mechanism that triggers pan-nuclear silencing of rRNA transcription in response to DNA damage. This is associated with transient...... recruitment of the Nijmegen breakage syndrome protein 1 (NBS1), a central regulator of DNA damage responses, into the nucleoli. We further identify TCOF1 (also known as Treacle), a nucleolar factor implicated in ribosome biogenesis and mutated in Treacher Collins syndrome, as an interaction partner of NBS1...

Non-equilibrium repressor binding kinetics link DNA damage dose to transcriptional timing within the SOS gene network.

Science.gov (United States)

Culyba, Matthew J; Kubiak, Jeffrey M; Mo, Charlie Y; Goulian, Mark; Kohli, Rahul M

2018-06-01

Biochemical pathways are often genetically encoded as simple transcription regulation networks, where one transcription factor regulates the expression of multiple genes in a pathway. The relative timing of each promoter's activation and shut-off within the network can impact physiology. In the DNA damage repair pathway (known as the SOS response) of Escherichia coli, approximately 40 genes are regulated by the LexA repressor. After a DNA damaging event, LexA degradation triggers SOS gene transcription, which is temporally separated into subsets of 'early', 'middle', and 'late' genes. Although this feature plays an important role in regulating the SOS response, both the range of this separation and its underlying mechanism are not experimentally defined. Here we show that, at low doses of DNA damage, the timing of promoter activities is not separated. Instead, timing differences only emerge at higher levels of DNA damage and increase as a function of DNA damage dose. To understand mechanism, we derived a series of synthetic SOS gene promoters which vary in LexA-operator binding kinetics, but are otherwise identical, and then studied their activity over a large dose-range of DNA damage. In distinction to established models based on rapid equilibrium assumptions, the data best fit a kinetic model of repressor occupancy at promoters, where the drop in cellular LexA levels associated with higher doses of DNA damage leads to non-equilibrium binding kinetics of LexA at operators. Operators with slow LexA binding kinetics achieve their minimal occupancy state at later times than operators with fast binding kinetics, resulting in a time separation of peak promoter activity between genes. These data provide insight into this remarkable feature of the SOS pathway by demonstrating how a single transcription factor can be employed to control the relative timing of each gene's transcription as a function of stimulus dose.

Investigating the Relationship between Social Damages and the Quality of Life in Yazd City

Directory of Open Access Journals (Sweden)

M AfkhamiAghda

2016-06-01

Full Text Available Introduction: Social damages as a serious threat will serionsly jeopardize people health. Different factors including uncontrolled population growth, urban development, mechanization of life, disruption of interrelationships, etc. are some causes of social damages that might affect the quality of life. This study was conducted with the aim of investigating the relationship between social damages on the quality of life in Yazd city. Methods: This study is a descriptive survey one. The target population of this study was the families living in Yazd city. According to Krejcie and Morgan (1970 the sample size was 384. The samples were selected through cluster sampling. A 42-item pathology questionnaire and a 26-item quality of life questionnaire were used to collect the data. The data were analyzed using SPSS.16 software. Pearson correlation coefficient and analysis of variance were used. Results: The results showed that %95.3 of cases had a low tendency to social damages and there was a significant relationship between social damages and the quality of life. There was also a significant relationship between social damages such as theft, violence, drug abuse, sexual issues, suicide, running from home and quality of life. Conclusion: The results showed that there was a significant relationship between social damages and the quality of life, which it causes numerous problems for the society and it can have a negative effect on the people’s mental and physical health and decreases the quality of life.

Damage detection strategies for aircraft shell-like structures based on propagation guided elastic waves

International Nuclear Information System (INIS)

Zak, A; Ostachowicz, W; Krawczuk, M

2011-01-01

Damage of aircraft structural elements in any form always present high risks. Failures of these elements can be caused by various reasons including material fatigue or impact leading to damage initiation and growth. Detection of these failures at their earliest stage of development, estimation of their size and location, are one of the most crucial factors for each damage detection method. Structural health monitoring strategies based on propagation of guided elastic waves in structures and wave interaction with damage related discontinuities are very promising tools that offer not only damage detection capabilities, but are also meant to provide precise information about the state of the structures and their remaining lifetime. Because of that various techniques are employed to simulate and mimic the wave-discontinuity interactions. The use of various types of sensors, their networks together with sophisticated contactless measuring techniques are investigated both numerically and experimentally. Certain results of numerical simulations obtained by the use of the spectral finite element method are presented by the authors and related with propagation of guided elastic waves in shell-type aircraft structures. Two types of structures are considered: flat 2D panels with or without stiffeners and 3D shell structures. The applicability of two different damage detection approaches is evaluated in order to detect and localise damage in these structures. Selected results related with the use of laser scanning vibrometry are also presented and discussed by the authors.

Cellular and molecular mechanisms of cigarette smoke-induced lung damage and prevention by vitamin C

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Roy Siddhartha

2008-11-01

Full Text Available Abstract Background Cigarette smoke-induced cellular and molecular mechanisms of lung injury are not clear. Cigarette smoke is a complex mixture containing long-lived radicals, including p-benzosemiquinone that causes oxidative damage. Earlier we had reported that oxidative protein damage is an initial event in smoke-induced lung injury. Considering that p-benzosemiquinone may be a causative factor of lung injury, we have isolated p-benzosemiquinone and compared its pathophysiological effects with cigarette smoke. Since vitamin C is a strong antioxidant, we have also determined the modulatory effect of vitamin C for preventing the pathophysiological events. Methods Vitamin C-restricted guinea pigs were exposed to cigarette smoke (5 cigarettes/day; 2 puffs/cigarette for 21 days with and without supplementation of 15 mg vitamin C/guinea pig/day. Oxidative damage, apoptosis and lung injury were assessed in vitro, ex vivo in A549 cells as well as in vivo in guinea pigs. Inflammation was measured by neutrophilia in BALF. p-Benzosemiquinone was isolated from freshly prepared aqueous extract of cigarette smoke and characterized by various physico-chemical methods, including mass, NMR and ESR spectroscopy. p-Benzosemiquinone-induced lung damage was examined by intratracheal instillation in guinea pigs. Lung damage was measured by increased air spaces, as evidenced by histology and morphometric analysis. Oxidative protein damage, MMPs, VEGF and VEGFR2 were measured by western blot analysis, and formation of Michael adducts using MALDI-TOF-MS. Apoptosis was evidenced by TUNEL assay, activation of caspase 3, degradation of PARP and increased Bax/Bcl-2 ratio using immunoblot analysis and confocal microscopy. Results Exposure of guinea pigs to cigarette smoke resulted in progressive protein damage, inflammation, apoptosis and lung injury up to 21 days of the experimental period. Administration of 15 mg of vitamin C/guinea pig/day prevented all these

Leukotriene-mediated neuroinflammation, toxic brain damage, and neurodegeneration in acute methanol poisoning