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Sample records for genetic defects induced

  1. Genetic Counseling for Congenital Heart Defects

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Genetic Counseling for Congenital Heart Defects Updated:Jan 19,2018 ... with congenital heart disease considers having children. Genetic counseling can help answer these questions and address your ...

  2. The genetic defect in Cockayne syndrome is associated with a defect in repair of UV-induced DNA damage in transcriptionally active DNA

    International Nuclear Information System (INIS)

    Venema, J.; Mullenders, L.H.; Natarajan, A.T.; van Zeeland, A.A.; Mayne, L.V.

    1990-01-01

    Cells from patients with Cockayne syndrome (CS) are hypersensitive to UV-irradiation but have an apparently normal ability to remove pyrimidine dimers from the genome overall. We have measured the repair of pyrimidine dimers in defined DNA sequences in three normal and two CS cell strains. When compared to a nontranscribed locus, transcriptionally active genes were preferentially repaired in all three normal cell strains. There was no significant variation in levels of repair between various normal individuals or between two constitutively expressed genes, indicating that preferential repair may be a consistent feature of constitutively expressed genes in human cells. Neither CS strain, from independent complementation groups, was able to repair transcriptionally active DNA with a similar rate and to the same extent as normal cells, indicating that the genetic defect in CS lies in the pathway for repair of transcriptionally active DNA. These results have implications for understanding the pleiotropic clinical effects associated with disorders having defects in the repair of DNA damage. In particular, neurodegeneration appears to be associated with the loss of preferential repair of active genes and is not simply correlated with reduced levels of overall repair

  3. The Use of Patient-Specific Induced Pluripotent Stem Cells (iPSCs to Identify Osteoclast Defects in Rare Genetic Bone Disorders

    Directory of Open Access Journals (Sweden)

    I-Ping Chen

    2014-12-01

    Full Text Available More than 500 rare genetic bone disorders have been described, but for many of them only limited treatment options are available. Challenges for studying these bone diseases come from a lack of suitable animal models and unavailability of skeletal tissues for studies. Effectors for skeletal abnormalities of bone disorders may be abnormal bone formation directed by osteoblasts or anomalous bone resorption by osteoclasts, or both. Patient-specific induced pluripotent stem cells (iPSCs can be generated from somatic cells of various tissue sources and in theory can be differentiated into any desired cell type. However, successful differentiation of hiPSCs into functional bone cells is still a challenge. Our group focuses on the use of human iPSCs (hiPSCs to identify osteoclast defects in craniometaphyseal dysplasia. In this review, we describe the impact of stem cell technology on research for better treatment of such disorders, the generation of hiPSCs from patients with rare genetic bone disorders and current protocols for differentiating hiPSCs into osteoclasts.

  4. Separating genetic and hemodynamic defects in neuropilin 1 knockout embryos.

    Science.gov (United States)

    Jones, Elizabeth A V; Yuan, Li; Breant, Christine; Watts, Ryan J; Eichmann, Anne

    2008-08-01

    Targeted inactivation of genes involved in murine cardiovascular development frequently leads to abnormalities in blood flow. As blood fluid dynamics play a crucial role in shaping vessel morphology, the presence of flow defects generally prohibits the precise assignment of the role of the mutated gene product in the vasculature. In this study, we show how to distinguish between genetic defects caused by targeted inactivation of the neuropilin 1 (Nrp1) receptor and hemodynamic defects occurring in homozygous knockout embryos. Our analysis of a Nrp1 null allele bred onto a C57BL/6 background shows that vessel remodeling defects occur concomitantly with the onset of blood flow and cause death of homozygous mutants at E10.5. Using mouse embryo culture, we establish that hemodynamic defects are already present at E8.5 and continuous circulation is never established in homozygous mutants. The geometry of yolk sac blood vessels is altered and remodeling into yolk sac arteries and veins does not occur. To separate flow-induced deficiencies from those caused by the Nrp1 mutation, we arrested blood flow in cultured wild-type and mutant embryos and followed their vascular development. We find that loss of Nrp1 function rather than flow induces the altered geometry of the capillary plexus. Endothelial cell migration, but not replication, is altered in Nrp1 mutants. Gene expression analysis of endothelial cells isolated from freshly dissected wild-type and mutants and after culture in no-flow conditions showed down-regulation of the arterial marker genes connexin 40 and ephrin B2 related to the loss of Nrp1 function. This method allows genetic defects caused by loss-of-function of a gene important for cardiovascular development to be isolated even in the presence of hemodynamic defects.

  5. Basement Membrane Defects in Genetic Kidney Diseases

    Directory of Open Access Journals (Sweden)

    Christine Chew

    2018-01-01

    Full Text Available The glomerular basement membrane (GBM is a specialized structure with a significant role in maintaining the glomerular filtration barrier. This GBM is formed from the fusion of two basement membranes during development and its function in the filtration barrier is achieved by key extracellular matrix components including type IV collagen, laminins, nidogens, and heparan sulfate proteoglycans. The characteristics of specific matrix isoforms such as laminin-521 (α5β2γ1 and the α3α4α5 chain of type IV collagen are essential for the formation of a mature GBM and the restricted tissue distribution of these isoforms makes the GBM a unique structure. Detailed investigation of the GBM has been driven by the identification of inherited abnormalities in matrix proteins and the need to understand pathogenic mechanisms causing severe glomerular disease. A well-described hereditary GBM disease is Alport syndrome, associated with a progressive glomerular disease, hearing loss, and lens defects due to mutations in the genes COL4A3, COL4A4, or COL4A5. Other proteins associated with inherited diseases of the GBM include laminin β2 in Pierson syndrome and LMX1B in nail patella syndrome. The knowledge of these genetic mutations associated with GBM defects has enhanced our understanding of cell–matrix signaling pathways affected in glomerular disease. This review will address current knowledge of GBM-associated abnormalities and related signaling pathways, as well as discussing the advances toward disease-targeted therapies for patients with glomerular disease.

  6. Genetics Home Reference: abdominal wall defect

    Science.gov (United States)

    ... are two main types of abdominal wall defects: omphalocele and gastroschisis . Omphalocele is an opening in the center of the ... covering the exposed organs in gastroschisis. Fetuses with omphalocele may grow slowly before birth (intrauterine growth retardation) ...

  7. Metastable light induced defects in pentacene

    Energy Technology Data Exchange (ETDEWEB)

    Liguori, R.; Aprano, S.; Rubino, A. [Department of Industrial Engineering (DIIn), University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano (Italy)

    2014-02-21

    In this study we analyzed one of the environmental factors that could affect organic materials. Pentacene thin film samples were fabricated and the degradation of their electrical characteristics was measured when the devices were exposed to ultraviolet light irradiation. The results have been reported in terms of a trap density model, which provides a description of the dynamics of light induced electrically active defects in an organic semiconductor.

  8. Genetic Engineering and the Amelioration of Genetic Defect

    Science.gov (United States)

    Lederberg, Joshua

    1970-01-01

    Discusses the claims for a brave new world of genetic manipulation" and concludes that if we could agree upon applying genetic (or any other effective) remedies to global problems we probably would need no rescourse to them. Suggests that effective methods of preventing genetic disease are prevention of mutations and detection and…

  9. Graphene defects induced by ion beam

    Science.gov (United States)

    Gawlik, Grzegorz; Ciepielewski, Paweł; Baranowski, Jacek; Jagielski, Jacek

    2017-10-01

    The CVD graphene deposited on the glass substrate was bombarded by molecular carbon ions C3+ C6+ hydrocarbon ions C3H4+ and atomic ions He+, C+, N+, Ar+, Kr+ Yb+. Size and density of ion induced defects were estimated from evolution of relative intensities of Raman lines D (∼1350 1/cm), G (∼1600 1/cm), and D‧ (∼1620 1/cm) with ion fluence. The efficiency of defect generation by atomic ions depend on ion mass and energy similarly as vacancy generation directly by ion predicted by SRIM simulations. However, efficiency of defect generation in graphene by molecular carbon ions is essentially higher than summarized efficiency of similar group of separate atomic carbon ions of the same energy that each carbon ion in a cluster. The evolution of the D/D‧ ratio of Raman lines intensities with ion fluence was observed. This effect may indicate evolution of defect nature from sp3-like at low fluence to a vacancy-like at high fluence. Observed ion graphene interactions suggest that the molecular ion interacts with graphene as single integrated object and should not be considered as a group of atomic ions with partial energy.

  10. Nuclear genetic defects of mitochondrial ATP synthase

    Czech Academy of Sciences Publication Activity Database

    Hejzlarová, Kateřina; Mráček, Tomáš; Vrbacký, Marek; Kaplanová, Vilma; Karbanová, Vendula; Nůsková, Hana; Pecina, Petr; Houštěk, Josef

    2014-01-01

    Roč. 63, Suppl.1 (2014), S57-S71 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GAP303/11/0970; GA ČR GAP303/12/1363; GA MZd(CZ) NT12370; GA MZd(CZ) NT14050 Grant - others:Univerzita Karlova(CZ) 370411 Institutional support: RVO:67985823 Keywords : mitochondrial diseases * TMEM70 * ATPAF1 * ATP5A1 * ATP5E Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.293, year: 2014

  11. The investigation of radiation induced defects in MgO

    International Nuclear Information System (INIS)

    Puetz, M.

    1990-05-01

    In this paper Frenkel defects were induced in MgO by 3 MeV electrons at low temperature. These defects were investigated by measurements of the optical absorption, by investigating the lattice parameters and Huang diffuse scattering. (WL)

  12. Electron irradiation-induced defects in {beta}-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Ryuichiro [Osaka Prefectural Univ., Sakai (Japan). Reseach Inst. for Advanced Science and Technology

    1996-04-01

    To add information of point defects in cubic crystal SiC, polycrystal {beta}-SiC on the market was used as sample and irradiated by neutron and electron. In situ observation of neutron and electron irradiation-induced defects in {beta}-SiC were carried out by ultra high-voltage electronic microscope (UHVEM) and ordinary electronic microscope. The obtained results show that the electron irradiation-induced secondary defects are micro defects less than 20 nm at about 1273K, the density of defects is from 2x10{sup 17} to 1x10{sup 18}/cc, the secondary defects may be hole type at high temperature and the preexistant defects control nuclear formation of irradiation-induced defects, effective sink. (S.Y.)

  13. The familial hyperchylomicronemia syndrome: New insights into underlying genetic defects

    Energy Technology Data Exchange (ETDEWEB)

    Santamarina-Fojo, S.; Brewer, H.B. (National Inst. of Health, Bethesda, MD (United States))

    1991-02-20

    This case history reports the diagnosis of familial hyperchylomicronemia, a rare genetic syndrome inherited as an autosomal recessive trait. It is characterized by severe fasting hypertriglyceridemia and massive accumulations of chylomicrons in plasma. The two major molecular defects in the disease are a deficiency of lipoprotein lipase or of apo C-II. The location of the mutations in the human apolipoprotein (apo) C-II gene are identified.

  14. Study of EUV induced defects on few-layer graphene

    NARCIS (Netherlands)

    Gao, An; Rizo, P.J.; Zoethout, E.; Scaccabarozzi, L.; Lee, Christopher James; Banine, V.; Bijkerk, Frederik

    2012-01-01

    Defects in graphene greatly affect its properties1-3. Radiation induced-defects may reduce the long-term survivability of graphene-based nano-devices. Here, we expose few-layer graphene to extreme ultraviolet (EUV, 13.5nm) radiation and show there is a power-dependent increase in defect density. We

  15. What’s new in genetics of congenital heart defects

    Directory of Open Access Journals (Sweden)

    Maria Cristina Digilio

    2016-12-01

    Full Text Available Epidemiological studies, clinical observations and advances in molecular genetics are contributing to the understanding of the etiology of congenital heart defects (CHDs. Several phenotype-genotype correlation studies have suggested that specific morphogenetic mechanisms put in motion by genes can result in a specific cardiac phenotype. The use of new technologies has increased the possibility of identification of new genes and chromosomal loci in syndromic and non-syndromic CHDs. There are a number of methods available for genetic research studies of CHDs, including cytogenetic analysis, linkage and association studies, copy number variation (CNV and DNA micro-array analysis, and whole exome sequencing. The altered dosage of contigous genes included inside CNVs can produce new syndromic CHDs, so that several different new genomic conditions have been identified. These include duplication 22q11.2 syndrome, distal 22q11.2 deletion syndrome, deletion and duplication 1q21.1, deletion 1p36 syndrome. Molecular techniques as whole exome sequancing has lead to the identification of new genes for monogenic syndromes with CHD, as for example in Adams-Oliver, Noonan and Kabuki syndrome. The variable expressivity and reduced penetrance of CHDs in genetic syndromes is likely influenced by genetic factors, and several studies have been performed showing the involvement of modifier genes. It is not easy to define precisely the genetic defects underlying non-syndromic CHDs, due to the genetic and clinical heterogeneity of these malformations. Recent experimental studies have identified multiple CNVs contributing to non-syndromic CHD. The number of identified genes for non-syndromic CHDs is at this time limited and each of the identified gene has been shown to be implicated only in a small proportion of CHD. The application of new technologies to specific cases of CHD and pedigrees with familial recurrence and filtering genes mapping in CNV regions can probably

  16. Defect-induced mix experiment for NIF

    Directory of Open Access Journals (Sweden)

    Schmitt M.J.

    2013-11-01

    Full Text Available The Defect Induced Mix Experiment (DIME-II will measure the implosion and mix characteristics of CH capsules filled with 5 atmospheres of DT by incorporating mid-Z dopant layers of Ge and Ga. This polar direct drive (PDD experiment also will demonstrate the filling of a CH capsule at target chamber center using a fill tube. Diagnostics for these experiments include areal x-ray backlighting to obtain early time images of the implosion trajectory and a multiple-monochromatic imager (MMI to collect spectrally-resolved images of the capsule dopant line emission near bangtime. The inclusion of two (or more thin dopant layers at separate depths within the capsule shell facilitates spatial correlation of mix between the layers and the hot gas core on a single shot. The dopant layers are typically 2 μm thick and contain dopant concentrations of 1.5%. Three dimensional Hydra simulations have been performed to assess the effects of PDD asymmetry on capsule performance.

  17. Genetic, chromosomal, and syndromic causes of neural tube defects

    Science.gov (United States)

    Seidahmed, Mohammed Z.; Abdelbasit, Omer B.; Shaheed, Meeralebbae M.; Alhussein, Khalid A.; Miqdad, Abeer M.; Samadi, Abdulmohsen S.; Khalil, Mohammed I.; Al-Mardawi, Elham; Salih, Mustafa A.

    2014-01-01

    Objective: To ascertain the incidence, and describe the various forms of neural tube defects (NTDs) due to genetic, chromosomal, and syndromic causes. Methods: We carried out a retrospective analysis of data retrieved from the medical records of newborn infants admitted to the Neonatal Intensive Care Unit with NTDs and their mothers spanning 14 years (1996-2009) at the Security Forces Hospital, Riyadh, Saudi Arabia. The cases were ascertained by a perinatologist, neonatologist, geneticist, radiologist, and neurologist. The literature was reviewed via a MEDLINE search. Only liveborn babies were included. Permission from the Educational Committee at the Security Forces Hospital was obtained prior to the collection of data. Results: Out of 103 infants with NTDs admitted during this period, 20 (19.4%) were found to have an underlying genetic syndromic, chromosomal and/or other anomalies. There were 5 cases of Meckel-Gruber syndrome, 2 Joubert syndrome, one Waardenburg syndrome, one Walker-Warburg syndrome, 2 chromosomal disorders, 2 caudal regression, one amniotic band disruption sequence, one associated with omphalocele, one with diaphragmatic hernia, and 4 with multiple congenital anomalies. Conclusions: There is a high rate of underlying genetic syndromic and/or chromosomal causes of NTDs in the Saudi Arabian population due to the high consanguinity rate. Identification of such association can lead to more accurate provisions of genetic counseling to the family including preimplantation genetic diagnosis or early termination of pregnancies associated with lethal conditions. PMID:25551112

  18. Genetic, chromosomal, and syndromic causes of neural tube defects.

    Science.gov (United States)

    Seidahmed, Mohammed Z; Abdelbasit, Omer B; Shaheed, Meeralebbae M; Alhussein, Khalid A; Miqdad, Abeer M; Samadi, Abdulmohsen S; Khalil, Mohammed I; Al-Mardawi, Elham; Salih, Mustafa A

    2014-12-01

    To ascertain the incidence, and describe the various forms of neural tube defects (NTDs) due to genetic, chromosomal, and syndromic causes. We carried out a retrospective analysis of data retrieved from the medical records of newborn infants admitted to the Neonatal Intensive Care Unit with NTDs and their mothers spanning 14 years (1996-2009) at the Security Forces Hospital, Riyadh, Saudi Arabia. The cases were ascertained by a perinatologist, neonatologist, geneticist, radiologist, and neurologist. The literature was reviewed via a MEDLINE search. Only liveborn babies were included. Permission from the Educational Committee at the Security Forces Hospital was obtained prior to the collection of data. Out of 103 infants with NTDs admitted during this period, 20 (19.4%) were found to have an underlying genetic syndromic, chromosomal and/or other anomalies. There were 5 cases of Meckel-Gruber syndrome, 2 Joubert syndrome, one Waardenburg syndrome, one Walker-Warburg syndrome, 2 chromosomal disorders, 2 caudal regression, one amniotic band disruption sequence, one associated with omphalocele, one with diaphragmatic hernia, and 4 with multiple congenital anomalies. There is a high rate of underlying genetic syndromic and/or chromosomal causes of NTDs in the Saudi Arabian population due to the high consanguinity rate. Identification of such association can lead to more accurate provisions of genetic counseling to the family including preimplantation genetic diagnosis or early termination of pregnancies associated with lethal conditions.

  19. Genetic analysis of metabolic defects in the spontaneously hypertensive rat

    Czech Academy of Sciences Publication Activity Database

    Pravenec, Michal; Zídek, Václav; Musilová, Alena; Šimáková, Miroslava; Kostka, Vlastimil; Mlejnek, Petr; Křen, Vladimír; Křenová, D.; Bílá, V.; Míková, B.; Jáchymová, M.; Horký, K.; Kazdová, L.; St.Lezin, E.; Kurtz, W. T.

    2002-01-01

    Roč. 13, č. 5 (2002), s. 253-258 ISSN 0938-8990 R&D Projects: GA MŠk LN00A079; GA ČR GV204/98/K015; GA ČR GA305/00/1646; GA MŠk NB5299 Grant - others:NIH(US) RO1 HL56028; NIH(US) PO1 HL35018; HHMI(US) 55000331 Institutional research plan: CEZ:AV0Z5011922 Keywords : metabolic defects * spontaneously hypertensive rat Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.233, year: 2002

  20. Impurity Role In Mechanically Induced Defects

    International Nuclear Information System (INIS)

    Howell, R.H.; Asoka-Kumar, P.; Hartley, J.; Sterne, P.

    2000-01-01

    An improved understanding of dislocation dynamics and interactions is an outstanding problem in the multi scale modeling of materials properties, and is the current focus of major theoretical efforts world wide. We have developed experimental and theoretical tools that will enable us to measure and calculate quantities defined by the defect structure. Unique to the measurements is a new spectroscopy that determines the detailed elemental composition at the defect site. The measurements are based on positron annihilation spectroscopy performed with a 3 MeV positron beam [1]. Positron annihilation spectroscopy is highly sensitive to dislocations and associated defects and can provide unique elements of the defect size and structure. Performing this spectroscopy with a highly penetrating positron beam enables flexibility in sample handling. Experiments on fatigued and stressed samples have been done and in situ measurement capabilities have been developed. We have recently performed significant upgrades to the accelerator operation and novel new experiments have been performed [2-4] To relate the spectrographic results and the detailed structure of a defect requires detailed calculations. Measurements are coupled with calculated results based on a description of positions of atoms at the defect. This gives an atomistic view of dislocations and associated defects including impurity interactions. Our ability to probe impurity interactions is a unique contribution to defect understanding not easily addressed by other atomistic spectroscopies

  1. Cancers and genetic defects resulting from the use of various energy sources

    International Nuclear Information System (INIS)

    Myers, D.K.

    1978-06-01

    A review of recent literature on carcinogenic effects of chemical products derived from the combustion of organic fuels suggests that the numbers of fatal cancers and genetic defects induced by utilization of fossil fuels may be much greater than the numbers induced by utilization of nuclear power to produce the same amount of energy. Despite the uncertainties involved in these estimates, the maximum risk of fatal cancers due to carcinogenic by-products associated with the production of electricity by any of these methods appears to be remarkably low compared with the risk of other fatal hazards in Canada and the U.S.A. (author)

  2. Study of irradiation induced defects in silicon

    International Nuclear Information System (INIS)

    Pal, Gayatri; Sebastian, K.C.; Somayajulu, D.R.S.; Chintalapudi, S.N.

    2000-01-01

    Pure high resistivity (6000 ohm-cm) silicon wafers were recoil implanted with 1.8 MeV 111 In ions. As-irradiated wafers showed a 13 MHz quadrupole interaction frequency, which was not observed earlier. The annealing behaviour of these defects in the implanted wafers was studied between room temperature and 1073 K. At different annealing temperatures two more interaction frequencies corresponding to defect complexes D2 and D3 are observed. Even though the experimental conditions were different, these are identical to the earlier reported ones. Based on an empirical point charge model calculation, an attempt is made to identify the configuration of these defect complexes. (author)

  3. Induced Magnetic Moment in Defected Single-Walled Carbon Nanotubes

    International Nuclear Information System (INIS)

    Liu Hong

    2006-01-01

    The existence of a large induced magnetic moment in defect single-walled carbon nanotube(SWNT) is predicted using the Green's function method. Specific to this magnetic moment of defect SWNT is its magnitude which is several orders of magnitude larger than that of perfect SWNT. The induced magnetic moment also shows certain remarkable features. Therefore, we suggest that two pair-defect orientations in SWNT can be distinguished in experiment through the direction of the induced magnetic moment at some Specific energy points

  4. Light-induced defect creation in hydrogenated polymorphous silicon

    International Nuclear Information System (INIS)

    Morigaki, K.; Takeda, K.; Hikita, H.; Roca i Cabarrocas, P.

    2005-01-01

    Light-induced defect creation in hydrogenated polymorphous silicon (pm-Si:H) is investigated from electron spin resonance measurements and is compared with that in hydrogenated amorphous silicon (a-Si:H). Light-induced defect creation occurs at room temperature similarly for both types of films prepared at 250 deg. C. Thermal annealing of light-induced defects is also investigated as a function of temperature. Different behaviours of annealing characteristics for pm-Si:H from those for a-Si:H are observed and discussed. In particular, we observed a decrease of the light-induced defect creation efficiency with repeated light-soaking-annealing cycles and discuss it with respect to the hydrogen bonding in pm-Si:H films

  5. Cellular structure formed by ion-implantation-induced point defect

    International Nuclear Information System (INIS)

    Nitta, N.; Taniwaki, M.; Hayashi, Y.; Yoshiie, T.

    2006-01-01

    The authors have found that a cellular defect structure is formed on the surface of Sn + ion implanted GaSb at a low temperature and proposed its formation mechanism based on the movement of the induced point defects. This research was carried out in order to examine the validity of the mechanism by clarifying the effect of the mobility of the point defects on the defect formation. The defect structure on the GaSb surfaces implanted at cryogenic temperature and room temperature was investigated by scanning electron microscopy (SEM) and cross-sectional transmission electron microscopy (TEM) observation. In the sample implanted at room temperature, the sponge-like structure (a pileup of voids) was formed and the cellular structure, as observed at a low temperature, did not develop. This behavior was explained by the high mobility of the vacancies during implantation at room temperature, and the proposed idea that the defect formation process is dominated by the induced point defects was confirmed

  6. Weak Defect Identification for Centrifugal Compressor Blade Crack Based on Pressure Sensors and Genetic Algorithm.

    Science.gov (United States)

    Li, Hongkun; He, Changbo; Malekian, Reza; Li, Zhixiong

    2018-04-19

    The Centrifugal compressor is a piece of key equipment for petrochemical factories. As the core component of a compressor, the blades suffer periodic vibration and flow induced excitation mechanism, which will lead to the occurrence of crack defect. Moreover, the induced blade defect usually has a serious impact on the normal operation of compressors and the safety of operators. Therefore, an effective blade crack identification method is particularly important for the reliable operation of compressors. Conventional non-destructive testing and evaluation (NDT&E) methods can detect the blade defect effectively, however, the compressors should shut down during the testing process which is time-consuming and costly. In addition, it can be known these methods are not suitable for the long-term on-line condition monitoring and cannot identify the blade defect in time. Therefore, the effective on-line condition monitoring and weak defect identification method should be further studied and proposed. Considering the blade vibration information is difficult to measure directly, pressure sensors mounted on the casing are used to sample airflow pressure pulsation signal on-line near the rotating impeller for the purpose of monitoring the blade condition indirectly in this paper. A big problem is that the blade abnormal vibration amplitude induced by the crack is always small and this feature information will be much weaker in the pressure signal. Therefore, it is usually difficult to identify blade defect characteristic frequency embedded in pressure pulsation signal by general signal processing methods due to the weakness of the feature information and the interference of strong noise. In this paper, continuous wavelet transform (CWT) is used to pre-process the sampled signal first. Then, the method of bistable stochastic resonance (SR) based on Woods-Saxon and Gaussian (WSG) potential is applied to enhance the weak characteristic frequency contained in the pressure

  7. Iridoschisis: high frequency ultrasound imaging. Evidence for a genetic defect?

    Science.gov (United States)

    Danias, J; Aslanides, I M; Eichenbaum, J W; Silverman, R H; Reinstein, D Z; Coleman, D J

    1996-01-01

    AIMS: To elucidate changes in the anatomy of the anterior chamber associated with iridoschisis, a rare form of iris atrophy, and their potential contribution to angle closure glaucoma. METHODS: Both eyes of a 71-year-old woman with bilateral iridoschisis and fibrous dysplasia and her asymptomatic 50-year-old daughter were scanned with a very high frequency (50 MHz) ultrasound system. RESULTS: The symptomatic patient exhibited diffuse changes in the iris stoma with an intact posterior iris pigmented layer in both eyes. These changes were clinically compatible with the lack of iris transillumination defects. Additionally, iris bowing with a resultant narrowing of the angle occurred. The asymptomatic daughter showed discrete, but less severe iris stromal changes. CONCLUSION: This is the first detailed study of high frequency ultrasonic imaging of the iris in iridoschisis. The observed structural changes suggest angle narrowing by forward bowing of the anterior iris stroma may be a mechanism of IOP elevation in this condition. The ultrasonic detection of iris changes in the asymptomatic daughter of the symptomatic patient and the association of iridoschisis with fibrous dysplasia suggest a possible genetic component in the pathogenesis of this condition. Images PMID:9059271

  8. Light-induced defects in hybrid lead halide perovskite

    Science.gov (United States)

    Sharia, Onise; Schneider, William

    One of the main challenges facing organohalide perovskites for solar application is stability. Solar cells must last decades to be economically viable alternatives to traditional energy sources. While some causes of instability can be avoided through engineering, light-induced defects can be fundamentally limiting factor for practical application of the material. Light creates large numbers of electron and hole pairs that can contribute to degradation processes. Using ab initio theoretical methods, we systematically explore first steps of light induced defect formation in methyl ammonium lead iodide, MAPbI3. In particular, we study charged and neutral Frenkel pair formation involving Pb and I atoms. We find that most of the defects, except negatively charged Pb Frenkel pairs, are reversible, and thus most do not lead to degradation. Negative Pb defects create a mid-gap state and localize the conduction band electron. A minimum energy path study shows that, once the first defect is created, Pb atoms migrate relatively fast. The defects have two detrimental effects on the material. First, they create charge traps below the conduction band. Second, they can lead to degradation of the material by forming Pb clusters.

  9. Defects induced by helium implantation in SiC

    International Nuclear Information System (INIS)

    Oliviero, E.; Barbot, J.F.; Declemy, A.; Beaufort, M.F.; Oliviero, E.

    2008-01-01

    SiC is one of the considered materials for nuclear fuel conditioning and for the fabrication of some core structures in future nuclear generation reactors. For the development of this advance technology, a fundamental research on this material is of prime importance. In particular, the implantation/irradiation effects have to be understood and controlled. It is with this aim that the structural alterations induced by implantation/irradiation in SiC are studied by different experimental techniques as transmission electron microscopy, helium desorption, X-ray diffraction and Rutherford backscattering spectrometry. In this work, the different types of defects induced by helium implantation in SiC, point or primary defects (obtained at low energy (∼100 eV) until spread defects (obtained at higher energy (until ∼2 MeV)) are exposed. The amorphization/recrystallization and swelling phenomena are presented too. (O.M.)

  10. Interaction of alpha radiation with thermally-induced defects in silicon

    International Nuclear Information System (INIS)

    Ali, Akbar; Majid, Abdul

    2008-01-01

    The interaction of radiation-induced defects created by energetic alpha particles and thermally-induced defects in silicon has been studied using a Deep Level Transient Spectroscopy (DLTS) technique. Two thermally-induced defects at energy positions E c -0.48 eV and E c -0.25 eV and three radiation-induced defects E2, E3 and E5 have been observed. The concentration of both of the thermally-induced defects has been observed to increase on irradiation. It has been noted that production rates of the radiation-induced defects are suppressed in the presence of thermally-induced defects. A significant difference in annealing characteristics of thermally-induced defects in the presence of radiation-induced defects has been observed compared to the characteristics measured in pre-irradiated samples

  11. Influence of radiation induced defect clusters on silicon particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Junkes, Alexandra

    2011-10-15

    The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) addresses some of today's most fundamental questions of particle physics, like the existence of the Higgs boson and supersymmetry. Two large general-purpose experiments (ATLAS, CMS) are installed to detect the products of high energy protonproton and nucleon-nucleon collisions. Silicon detectors are largely employed in the innermost region, the tracking area of the experiments. The proven technology and large scale availability make them the favorite choice. Within the framework of the LHC upgrade to the high-luminosity LHC, the luminosity will be increased to L=10{sup 35} cm{sup -2}s{sup -1}. In particular the pixel sensors in the innermost layers of the silicon trackers will be exposed to an extremely intense radiation field of mainly hadronic particles with fluences of up to {phi}{sub eq}=10{sup 16} cm{sup -2}. The radiation induced bulk damage in silicon sensors will lead to a severe degradation of the performance during their operational time. This work focusses on the improvement of the radiation tolerance of silicon materials (Float Zone, Magnetic Czochralski, epitaxial silicon) based on the evaluation of radiation induced defects in the silicon lattice using the Deep Level Transient Spectroscopy and the Thermally Stimulated Current methods. It reveals the outstanding role of extended defects (clusters) on the degradation of sensor properties after hadron irradiation in contrast to previous works that treated effects as caused by point defects. It has been found that two cluster related defects are responsible for the main generation of leakage current, the E5 defects with a level in the band gap at E{sub C}-0.460 eV and E205a at E{sub C}-0.395 eV where E{sub C} is the energy of the edge of the conduction band. The E5 defect can be assigned to the tri-vacancy (V{sub 3}) defect. Furthermore, isochronal annealing experiments have shown that the V{sub 3} defect

  12. Influence of radiation induced defect clusters on silicon particle detectors

    International Nuclear Information System (INIS)

    Junkes, Alexandra

    2011-10-01

    The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) addresses some of today's most fundamental questions of particle physics, like the existence of the Higgs boson and supersymmetry. Two large general-purpose experiments (ATLAS, CMS) are installed to detect the products of high energy protonproton and nucleon-nucleon collisions. Silicon detectors are largely employed in the innermost region, the tracking area of the experiments. The proven technology and large scale availability make them the favorite choice. Within the framework of the LHC upgrade to the high-luminosity LHC, the luminosity will be increased to L=10 35 cm -2 s -1 . In particular the pixel sensors in the innermost layers of the silicon trackers will be exposed to an extremely intense radiation field of mainly hadronic particles with fluences of up to Φ eq =10 16 cm -2 . The radiation induced bulk damage in silicon sensors will lead to a severe degradation of the performance during their operational time. This work focusses on the improvement of the radiation tolerance of silicon materials (Float Zone, Magnetic Czochralski, epitaxial silicon) based on the evaluation of radiation induced defects in the silicon lattice using the Deep Level Transient Spectroscopy and the Thermally Stimulated Current methods. It reveals the outstanding role of extended defects (clusters) on the degradation of sensor properties after hadron irradiation in contrast to previous works that treated effects as caused by point defects. It has been found that two cluster related defects are responsible for the main generation of leakage current, the E5 defects with a level in the band gap at E C -0.460 eV and E205a at E C -0.395 eV where E C is the energy of the edge of the conduction band. The E5 defect can be assigned to the tri-vacancy (V 3 ) defect. Furthermore, isochronal annealing experiments have shown that the V 3 defect exhibits a bistability, as does the leakage current. In oxygen

  13. Radiation defects in lithium fluoride induced by heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Trautmann, C.; Schwartz, K.; Steckenreiter, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Costantini, J.M. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France). DPTA/SPMC; Toulemonde, M. [Centre Interdisciplinaire de Recherches avec les Ions Lourds (CIRIL), 14 - Caen (France)

    1998-07-01

    Single crystals of lithium fluoride were irradiated with various species of heavy ions in the energy regime between 1 and 30 MeV/u. The induced radiation damage was studied with techniques such as optical absorption spectroscopy, small-angle x-ray scattering, chemical etching and profilometry, complemented by annealing experiments. Clear evidence is given for a complex track structure and defect morphology. Single defects such as F-centers are produced in a large halo of several tens of nanometers around the ion trajectory. The defect creation in this zone is similar to that under conventional radiation. For heavy ions above a critical energy loss of 10 keV/nm, new effects occur within a very small core region of 2-4 nm in diameter. The damage in this zone is responsible for chemical etching and for a characteristic anisotropic x-ray scattering. It is assumed that in this core, complex defect aggregates (e.g., cluster of color centers, molecular anions and vacancies) are created. Their formation is only slightly influenced by the irradiation temperature and takes place even at 15 K where diffusion processes of primary defects are frozen. Furthermore, irradiation with heavy ions leads to pronounced swelling effects which can be related to an intermediate zone of around 10 nm around the ion path. (orig.) 40 refs.

  14. Mobility of point defects induced by subthreshold collisions

    International Nuclear Information System (INIS)

    Tenenbaum, A.; Nguyen Van Doan

    1976-01-01

    The effect of thermal vibrations on atomic collision focusing was studied with the view to demonstrate that such collisions may induce point defect migration through the crystal. The persistence of the phenomenon of focused atomic collisions in a crystal at thermal equilibrium was studied, using a computer simulation by the Molecular Dynamics Technique. In the temperature range (0 to 500K) matter and momentum transfers in c.f.c. crystals proceed mainly by focused collisions along and directions. Their contribution to the induced migration of radiation defects was determined from the threshold energy of every primary able to be involved in the process. As an example, the quantitative model is applied to electron irradiation along the crystallographic directions [fr

  15. Birth defects and genetic disorders among Arab Americans--Michigan, 1992-2003.

    Science.gov (United States)

    Yanni, Emad A; Copeland, Glenn; Olney, Richard S

    2010-06-01

    Birth defects and genetic disorders are leading causes of infant morbidity and mortality in many countries. Population-based data on birth defects among Arab-American children have not been documented previously. Michigan has the second largest Arab-American community in the United States after California. Using data from the Michigan Birth Defects Registry (MBDR), which includes information on parents' country of birth and ancestry, birth prevalences were estimated in offspring of Michigan women of Arab ancestry for 21 major categories of birth defects and 12 congenital endocrine, metabolic, and hereditary disorders. Compared with other non-Hispanic white children in Michigan, Arab-American children had similar or lower birth prevalences of the selected types of structural birth defects, with higher rates of certain hereditary blood disorders and three categories of metabolic disorders. These estimates are important for planning preconception and antenatal health care, genetic counseling, and clinical care for Arab Americans.

  16. Ribosomal and hematopoietic defects in induced pluripotent stem cells derived from Diamond Blackfan anemia patients.

    Science.gov (United States)

    Garçon, Loïc; Ge, Jingping; Manjunath, Shwetha H; Mills, Jason A; Apicella, Marisa; Parikh, Shefali; Sullivan, Lisa M; Podsakoff, Gregory M; Gadue, Paul; French, Deborah L; Mason, Philip J; Bessler, Monica; Weiss, Mitchell J

    2013-08-08

    Diamond Blackfan anemia (DBA) is a congenital disorder with erythroid (Ery) hypoplasia and tissue morphogenic abnormalities. Most DBA cases are caused by heterozygous null mutations in genes encoding ribosomal proteins. Understanding how haploinsufficiency of these ubiquitous proteins causes DBA is hampered by limited availability of tissues from affected patients. We generated induced pluripotent stem cells (iPSCs) from fibroblasts of DBA patients carrying mutations in RPS19 and RPL5. Compared with controls, DBA fibroblasts formed iPSCs inefficiently, although we obtained 1 stable clone from each fibroblast line. RPS19-mutated iPSCs exhibited defects in 40S (small) ribosomal subunit assembly and production of 18S ribosomal RNA (rRNA). Upon induced differentiation, the mutant clone exhibited globally impaired hematopoiesis, with the Ery lineage affected most profoundly. RPL5-mutated iPSCs exhibited defective 60S (large) ribosomal subunit assembly, accumulation of 12S pre-rRNA, and impaired erythropoiesis. In both mutant iPSC lines, genetic correction of ribosomal protein deficiency via complementary DNA transfer into the "safe harbor" AAVS1 locus alleviated abnormalities in ribosome biogenesis and hematopoiesis. Our studies show that pathological features of DBA are recapitulated by iPSCs, provide a renewable source of cells to model various tissue defects, and demonstrate proof of principle for genetic correction strategies in patient stem cells.

  17. Defect-Induced Hedgehog Polarization States in Multiferroics

    Science.gov (United States)

    Li, Linze; Cheng, Xiaoxing; Jokisaari, Jacob R.; Gao, Peng; Britson, Jason; Adamo, Carolina; Heikes, Colin; Schlom, Darrell G.; Chen, Long-Qing; Pan, Xiaoqing

    2018-03-01

    Continuous developments in nanotechnology require new approaches to materials synthesis that can produce novel functional structures. Here, we show that nanoscale defects, such as nonstoichiometric nanoregions (NSNRs), can act as nano-building blocks for creating complex electrical polarization structures in the prototypical multiferroic BiFeO3 . An array of charged NSNRs are produced in BiFeO3 thin films by tuning the substrate temperature during film growth. Atomic-scale scanning transmission electron microscopy imaging reveals exotic polarization rotation patterns around these NSNRs. These polarization patterns resemble hedgehog or vortex topologies and can cause local changes in lattice symmetries leading to mixed-phase structures resembling the morphotropic phase boundary with high piezoelectricity. Phase-field simulations indicate that the observed polarization configurations are mainly induced by charged states at the NSNRs. Engineering defects thus may provide a new route for developing ferroelectric- or multiferroic-based nanodevices.

  18. Effect of irradiation-induced defects on fusion reactor ceramics

    International Nuclear Information System (INIS)

    Clinard, F.W. Jr.

    1986-01-01

    Structural, thermal, and electrical properties critical to performance of ceramics in a fusion environment can be profoundly altered by irradiation effects. Neutron damage may cause swelling, reduction of thermal conductivity, increase in dielectric loss, and either reduction or enhancement of strength depending on the crystal structure and defect content of the material. Absorption of ionizing energy inevitably leads to degradation of insulating properties, but these changes can be reduced by alterations in structural or compositional makeup. Assessment of the irradiation response of candidate ceramics Al 2 O 3 , MgAl 2 O 4 , SiC and Si 3 N 4 shows that each may find use in advanced fusion devices. The present understanding of irradiation-induced defects in ceramics, while far from complete, nevertheless points the way to methods for developing improved materials for fusion applications

  19. Genetics Home Reference: congenital bile acid synthesis defect type 1

    Science.gov (United States)

    ... result in softening and weakening of the bones ( rickets ) in some individuals. If left untreated, congenital bile ... Encyclopedia: Cholestasis Health Topic: Liver Diseases Health Topic: Rickets Genetic and Rare Diseases Information Center (1 link) ...

  20. Feasibility of identifying families for genetic studies of birth defects using the National Health Interview Survey

    Directory of Open Access Journals (Sweden)

    Nolan Vikki G

    2004-05-01

    Full Text Available Abstract Background The purpose of this study was to determine whether the National Health Interview Survey is a useful source to identify informative families for genetic studies of birth defects. Methods The 1994/1995 National Health Interview Survey (NHIS was used to identify households where individuals with two or more birth defects reside. Four groups of households were identified: 1 single non-familial (one individual with one birth defect; 2 single familial (more than one individual with one birth defect; 3 multiple non-familial (one individual with more than one birth defect, and 4 multiple familial (more than one individual with more than one birth defect. The March 2000 U.S. Census on households was used to estimate the total number of households in which there are individuals with birth defects. Results Of a total of 28,094 households and surveyed about birth defects and impairments, 1,083 single non-familial, 55 multiple non-familial, 54 single familial, and 8 multiple familial households were identified. Based on the 2000 U.S. census, it is estimated that there are 4,472,385 households where at least one person has one birth defect in the United States and in 234,846 of them there are at least two affected individuals. Western states had the highest prevalence rates. Conclusions Population-based methods, such as the NHIS, are modestly useful to identify the number and the regions where candidate families for genetic studies of birth defects reside. Clinic based studies and birth defects surveillance systems that collect family history offer better probability of ascertainment.

  1. Defects induced ferromagnetism in Mn doped ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Chattopadhyay, S.; Neogi, S.K. [Department of Physics, University of Calcutta, 92A P C Road, Kolkata 700009 (India); Sarkar, A. [Department of Physics, Bangabasi Morning College, Kolkata 700009 (India); Mukadam, M.D.; Yusuf, S.M. [Solid State Physics Division, Bhaba Atomic Research Centre, Mumbai 400085 (India); Banerjee, A. [Department of Physics, University of Calcutta, 92A P C Road, Kolkata 700009 (India); Bandyopadhyay, S., E-mail: sbaphy@caluniv.ac.i [Department of Physics, University of Calcutta, 92A P C Road, Kolkata 700009 (India)

    2011-02-15

    Single phase Mn doped (2 at%) ZnO samples have been synthesized by the solid-state reaction technique. Before the final sintering at 500 {sup o}C, the mixed powders have been milled for different milling periods (6, 24, 48 and 96 h). The grain sizes of the samples are very close to each other ({approx}32{+-}4 nm). However, the defective state of the samples is different from each other as manifested from the variation of magnetic properties and electrical resistivity with milling time. All the samples have been found to be ferromagnetic with clear hysteresis loops at room temperature. The maximum value for saturation magnetization (0.11 {mu}{sub B}/Mn atom) was achieved for 96 h milled sample. Electrical resistivity has been found to increase with increase in milling time. The most resistive sample bears the largest saturation magnetization. Variation of average positron lifetime with milling time bears a close similarity with that of the saturation magnetization. This indicates the key role played by open volume vacancy defects, presumably zinc vacancies near grain surfaces, in inducing ferromagnetic order in Mn doped ZnO. To attain optimum defect configuration favorable for ferromagnetism in this kind of samples proper choice of milling period and annealing conditions is required. - Research highlights: 2 at% Mn doped ZnO samples are single phase. All the samples exhibit ferromagnetism at room temperature. Correlation between saturation magnetization and positron annihilation lifetime established.

  2. Defects induced ferromagnetism in Mn doped ZnO

    International Nuclear Information System (INIS)

    Chattopadhyay, S.; Neogi, S.K.; Sarkar, A.; Mukadam, M.D.; Yusuf, S.M.; Banerjee, A.; Bandyopadhyay, S.

    2011-01-01

    Single phase Mn doped (2 at%) ZnO samples have been synthesized by the solid-state reaction technique. Before the final sintering at 500 o C, the mixed powders have been milled for different milling periods (6, 24, 48 and 96 h). The grain sizes of the samples are very close to each other (∼32±4 nm). However, the defective state of the samples is different from each other as manifested from the variation of magnetic properties and electrical resistivity with milling time. All the samples have been found to be ferromagnetic with clear hysteresis loops at room temperature. The maximum value for saturation magnetization (0.11 μ B /Mn atom) was achieved for 96 h milled sample. Electrical resistivity has been found to increase with increase in milling time. The most resistive sample bears the largest saturation magnetization. Variation of average positron lifetime with milling time bears a close similarity with that of the saturation magnetization. This indicates the key role played by open volume vacancy defects, presumably zinc vacancies near grain surfaces, in inducing ferromagnetic order in Mn doped ZnO. To attain optimum defect configuration favorable for ferromagnetism in this kind of samples proper choice of milling period and annealing conditions is required. - Research highlights: → 2 at% Mn doped ZnO samples are single phase. → All the samples exhibit ferromagnetism at room temperature. → Correlation between saturation magnetization and positron annihilation lifetime established.

  3. Modelling ionising radiation induced defect generation in bipolar oxides with gated diodes

    International Nuclear Information System (INIS)

    Barnaby, H.J.; Cirba, C.; Schrimpf, R.D.; Kosier, St.; Fouillat, P.; Montagner, X.

    1999-01-01

    Radiation-induced oxide defects that degrade electrical characteristics of bipolar junction transistor (BJTs) can be measured with the use of gated diodes. The buildup of defects and their effect on device radiation response are modeled with computer simulation. (authors)

  4. Radiation induced segregation and point defects in binary copper alloys

    International Nuclear Information System (INIS)

    Monteiro, W.A.

    1984-01-01

    Considerable progress, both theoretical and experimental, has been made in establishing and understanding the influence of factors such as temperature, time, displacement rate dependence and the effect of initial solute misfit on radiation induced solute diffusion and segregation. During irradiation, the composition of the alloy changes locally, due to defect flux driven non-equilibrium segregation near sinks such as voids, external surfaces and grain boundaries. This change in composition could influence properties and phenomena such as ductility, corrosion resistance, stress corrosion cracking, sputtering and blistering of materials used in thermo-nuclear reactors. In this work, the effect of 1 MeV electron irradiation on the initiation and development of segregation and defect diffusion in binary copper alloys has been studied in situ, with the aid of a high voltage electron microscope. The binary copper alloys had Be, Pt and Sn as alloying elements which had atomic radii less than, similar and greater than that of copper, respectively. It has been observed that in a wide irradiation temperature range, stabilization and growth of dislocation loops took place in Cu-Sn and Cu-Pt alloys. Whereas in the Cu-Be alloy, radiation induced precipitates formed and transformed to the stable γ phase. (Author) [pt

  5. Overview of Epidemiology, Genetics, Birth Defects, and Chromosome Abnormalities Associated With CDH

    Science.gov (United States)

    Pober, Barbara R.

    2010-01-01

    Congenital diaphragmatic hernia (CDH) is a common and well-studied birth defect. The etiology of most cases remains unknown but increasing evidence points to genetic causation. The data supporting genetic etiologies which are detailed below include the association of CDH with recurring chromosome abnormalities, the existence of CDH-multiplex families, and the co-occurrence of CDH with additional congenital malformations. PMID:17436298

  6. Proinsulin atypical maturation and disposal induces extensive defects in mouse Ins2+/Akita β-cells.

    Directory of Open Access Journals (Sweden)

    Qingxin Yuan

    Full Text Available Because of its low relative folding rate and plentiful manufacture in β-cells, proinsulin maintains a homeostatic balance of natively and plentiful non-natively folded states (i.e., proinsulin homeostasis, PIHO through the integration of maturation and disposal processes. PIHO is susceptible to genetic and environmental influences, and its disorder has been critically linked to defects in β-cells in diabetes. To explore this hypothesis, we performed polymerase chain reaction (PCR, metabolic-labeling, immunoblotting, and histological studies to clarify what defects result from primary disorder of PIHO in model Ins2(+/Akita β-cells. We used T antigen-transformed Ins2(+/Akita and control Ins2(+/+ β-cells established from Akita and wild-type littermate mice. In Ins2(+/Akita β-cells, we found no apparent defect at the transcriptional and translational levels to contribute to reduced cellular content of insulin and its precursor and secreted insulin. Glucose response remained normal in proinsulin biosynthesis but was impaired for insulin secretion. The size and number of mature insulin granules were reduced, but the size/number of endoplasmic reticulum, Golgi, mitochondrion, and lysosome organelles and vacuoles were expanded/increased. Moreover, cell death increased, and severe oxidative stress, which manifested as increased reactive oxygen species, thioredoxin-interacting protein, and protein tyrosine nitration, occurred in Ins2(+/Akita β-cells and/or islets. These data show the first clear evidence that primary PIHO imbalance induces severe oxidative stress and impairs glucose-stimulated insulin release and β-cell survival as well as producing other toxic consequences. The defects disclosed/clarified in model Ins2(+/Akita β-cells further support a role of the genetic and stress-susceptible PIHO disorder in β-cell failure and diabetes.

  7. The genetics of radiation-induced osteosarcoma

    International Nuclear Information System (INIS)

    Rosemann, M.; Kuosaite, V.; Nathrath, M.; Atkinson, M.J.

    2002-01-01

    Individual genetic variation can influence susceptibility to the carcinogenic effects of many environmental carcinogens. In radiation-exposed populations those individuals with a greater genetically determined susceptibility would be at greater risk of developing cancer. To include this modification of risk into radiation protection schemes it is necessary to identify the genes responsible for determining individual sensitivity. Alpha-particle-induced osteosarcoma in the mouse has been adopted as a model of human radiation carcinogenesis, and genome-wide screens have been conducted for allelic imbalance and genetic linkage. These studies have revealed a series of genes involved in determining the sensitivity to radiogenic osteosarcoma formation. (author)

  8. Genetic alterations during radiation-induced carcinogenesis

    International Nuclear Information System (INIS)

    Kodama, Seiji

    1995-01-01

    This paper reviews radiation-induced genetic alterations and its carcinogenesis, focusing on the previous in vitro assay outcome. A colony formation assay using Syrian hamster fetal cells and focus formation assay using mouse C3H10T1/2 cells are currently available to find malignant transformation of cells. Such in vitro assays has proposed the hypothesis that radiation-induced carcinogenesis arises from at least two-stage processes; i.e., that an early step induced by irradiation plays an important role in promoting the potential to cause the subsequent mutation. A type of genetic instability induced by radiation results in a persistently elevated frequency of spontaneous mutations, so-called the phenomenon of delayed reproductive death. One possible mechanism by which genetic instability arises has been shown to be due to the development of abnormality in the gene group involved in the maintenance mechanism of genome stability. Another possibility has also been shown to stem from the loss of telomere (the extremities of a chromosome). The importance of search for radiation-induced genetic instability is emphasized in view of the elucidation of carcinogenesis. (N.K.)

  9. Defect-induced conductance oscillations in short atomic chains

    International Nuclear Information System (INIS)

    Wawrzyniak-Adamczewska, M; Kostyrko, T

    2012-01-01

    Electronic transport through a junction made of two gold electrodes connected with a gold chain containing a silver impurity is analyzed with a tight binding model and the density-functional theory. It is shown that the conductance depends in a simple way on the position of the impurity in the chain and the parity of the total number of atoms of the chain. For an odd chain the conductance takes on a higher value when the Ag impurity substitutes an even Au atom in the chain, and a lower one for an odd position of the Ag atom. In the case of an even chain the conductance hardly depends on the position of the Ag atom. This new kind of a defect-induced parity oscillation of the conductance is significantly more prominent than the well-known even-odd effect related to the dependence of the conductance on the parity of number of atoms in perfect chains. (paper)

  10. Radiation induced defects and thermoluminescence mechanism in aluminum oxide

    Energy Technology Data Exchange (ETDEWEB)

    Atobe, K.; Kobayashi, T.; Awata, T. [Naruto Univ. of Education, Tokushima (Japan); Okada, M. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst; Nakagawa, M. [Kagawa Univ., Faculty of Education, Takamatsu, Kagawa (Japan)

    2001-01-01

    The thermoluminescence of the irradiated aluminum oxides were measured to study the radiation induced defects and their behaviors. Neutron and {gamma}-ray irradiation were performed for a shingle crystal of the high purity aluminum oxide. The thermoluminescence glow curve and its activation energy were measured. The spectroscopy measurement on the thermoluminescence and the absorption are also carried out. The observed 430 and 340 nm peaks are discussed relating to the F{sup +} and F centers, respectively. Activation state of the F center transits to 3P state through 1P state by emitting phonons. Trapped electron on 3P state emits phonon of 2.9 eV (430 nm) during transition to the ground state. The above reaction can be written by the equation. F{sup +} + e {yields} (F){sup *} {yields} F + h{nu}(2.9 eV, 470 nm). (Katsuta, H.)

  11. Ion beam induced defects in solids studied by optical techniques

    International Nuclear Information System (INIS)

    Comins, J.D.; Amolo, G.O.; Derry, T.E.; Connell, S.H.; Erasmus, R.M.; Witcomb, M.J.

    2009-01-01

    Optical methods can provide important insights into the mechanisms and consequences of ion beam interactions with solids. This is illustrated by four distinctly different systems. X- and Y-cut LiNbO 3 crystals implanted with 8 MeV Au 3+ ions with a fluence of 1 x 10 17 ions/cm 2 result in gold nanoparticle formation during high temperature annealing. Optical extinction curves simulated by the Mie theory provide the average nanoparticle sizes. TEM studies are in reasonable agreement and confirm a near-spherical nanoparticle shape but with surface facets. Large temperature differences in the nanoparticle creation in the X- and Y-cut crystals are explained by recrystallisation of the initially amorphised regions so as to recreate the prior crystal structure and to result in anisotropic diffusion of the implanted gold. Defect formation in alkali halides using ion beam irradiation has provided new information. Radiation-hard CsI crystals bombarded with 1 MeV protons at 300 K successfully produce F-type centres and V-centres having the I 3 - structure as identified by optical absorption and Raman studies. The results are discussed in relation to the formation of interstitial iodine aggregates of various types in alkali iodides. Depth profiling of I 3 - and I 5 - aggregates created in RbI bombarded with 13.6 MeV/A argon ions at 300 K is discussed. The recrystallisation of an amorphous silicon layer created in crystalline silicon bombarded with 100 keV carbon ions with a fluence of 5 x 10 17 ions/cm 2 during subsequent high temperature annealing is studied by Raman and Brillouin light scattering. Irradiation of tin-doped indium oxide (ITO) films with 1 MeV protons with fluences from 1 x 10 15 to 250 x 10 15 ions/cm -2 induces visible darkening over a broad spectral region that shows three stages of development. This is attributed to the formation of defect clusters by a model of defect growth and also high fluence optical absorption studies. X-ray diffraction studies show

  12. Ion beam induced defects in solids studied by optical techniques

    Science.gov (United States)

    Comins, J. D.; Amolo, G. O.; Derry, T. E.; Connell, S. H.; Erasmus, R. M.; Witcomb, M. J.

    2009-08-01

    Optical methods can provide important insights into the mechanisms and consequences of ion beam interactions with solids. This is illustrated by four distinctly different systems. X- and Y-cut LiNbO 3 crystals implanted with 8 MeV Au 3+ ions with a fluence of 1 × 10 17 ions/cm 2 result in gold nanoparticle formation during high temperature annealing. Optical extinction curves simulated by the Mie theory provide the average nanoparticle sizes. TEM studies are in reasonable agreement and confirm a near-spherical nanoparticle shape but with surface facets. Large temperature differences in the nanoparticle creation in the X- and Y-cut crystals are explained by recrystallisation of the initially amorphised regions so as to recreate the prior crystal structure and to result in anisotropic diffusion of the implanted gold. Defect formation in alkali halides using ion beam irradiation has provided new information. Radiation-hard CsI crystals bombarded with 1 MeV protons at 300 K successfully produce F-type centres and V-centres having the I3- structure as identified by optical absorption and Raman studies. The results are discussed in relation to the formation of interstitial iodine aggregates of various types in alkali iodides. Depth profiling of I3- and I5- aggregates created in RbI bombarded with 13.6 MeV/A argon ions at 300 K is discussed. The recrystallisation of an amorphous silicon layer created in crystalline silicon bombarded with 100 keV carbon ions with a fluence of 5 × 10 17 ions/cm 2 during subsequent high temperature annealing is studied by Raman and Brillouin light scattering. Irradiation of tin-doped indium oxide (ITO) films with 1 MeV protons with fluences from 1 × 10 15 to 250 × 10 15 ions/cm -2 induces visible darkening over a broad spectral region that shows three stages of development. This is attributed to the formation of defect clusters by a model of defect growth and also high fluence optical absorption studies. X-ray diffraction studies show

  13. The relationship between reaction kinetics and mutagenic action of monofunctional alkylating agents in higher eukaryotic systems. IV. The effects of the excision-defective mei-9L1 and mus(2)201D1 mutants on alkylation-induced genetic damage in Drosophila.

    Science.gov (United States)

    Vogel, E W; Dusenbery, R L; Smith, P D

    1985-04-01

    Repair-defective mutants of Drosophila melanogaster which identify two major DNA excision repair loci have been examined for their effects on alkylation-induced mutagenesis using the sex-linked recessive lethal assay as a measure of genotoxic endpoint. The alkylating agents (AAs) chosen for comparative analysis were selected on the basis of their reaction kinetics with DNA and included MMS, EMS, MNU, DMN, ENU, DEN and ENNG. Repair-proficient males were treated with the AAs and mated with either excision-defective mei-9L1 or mus(2)201D1 females or appropriate excision-proficient control females. The results of the present work suggest that a qualitative and quantitative relationship exists between the nature and the extent of chemical modification of DNA and the induction of of genetic alterations. The presence of either excision-defective mutant can enhance the frequency of mutation (hypermutability) and this hypermutability can be correlated with the Swain-Scott constant S of specific AAs such that as the SN1 character of the DNA alkylation reaction increases, the difference in response between repair-deficient and repair-proficient females decreases. The order of hypermutability of AAs with mei-9L1 relative to mei-9+ is MMS greater than MNU greater than DMN = EMS greater than iPMS = ENU = DEN = ENNG. When the percentage of lethal mutations induced in mei-9L1 females are plotted against those determined for control females, straight lines of different slopes are obtained. These mei-9L1/mei-9+ indices are: MMS = 7.6, MNU = 5.4, DMN = 2.4, EMS = 2.4 and iPMS = ENU = DEN = ENNG = 1. An identical order of hypermutability with similar indices is obtained for the mus(2)201 mutants: MMS(7.3) greater than MNU (5.4) greater than EMS(2.0) greater than ENU(1.1). Thus, absence of excision repair function has a significant effect on mutation production by AAs efficient in alkylating N-atoms in DNA but no measurable influence on mutation production by AAs most efficient in

  14. An Automated Defect Prediction Framework using Genetic Algorithms: A Validation of Empirical Studies

    Directory of Open Access Journals (Sweden)

    Juan Murillo-Morera

    2016-05-01

    Full Text Available Today, it is common for software projects to collect measurement data through development processes. With these data, defect prediction software can try to estimate the defect proneness of a software module, with the objective of assisting and guiding software practitioners. With timely and accurate defect predictions, practitioners can focus their limited testing resources on higher risk areas. This paper reports the results of three empirical studies that uses an automated genetic defect prediction framework. This framework generates and compares different learning schemes (preprocessing + attribute selection + learning algorithms and selects the best one using a genetic algorithm, with the objective to estimate the defect proneness of a software module. The first empirical study is a performance comparison of our framework with the most important framework of the literature. The second empirical study is a performance and runtime comparison between our framework and an exhaustive framework. The third empirical study is a sensitivity analysis. The last empirical study, is our main contribution in this paper. Performance of the software development defect prediction models (using AUC, Area Under the Curve was validated using NASA-MDP and PROMISE data sets. Seventeen data sets from NASA-MDP (13 and PROMISE (4 projects were analyzed running a NxM-fold cross-validation. A genetic algorithm was used to select the components of the learning schemes automatically, and to assess and report the results. Our results reported similar performance between frameworks. Our framework reported better runtime than exhaustive framework. Finally, we reported the best configuration according to sensitivity analysis.

  15. Polyglutamine toxicity in yeast induces metabolic alterations and mitochondrial defects

    KAUST Repository

    Papsdorf, Katharina

    2015-09-03

    Background Protein aggregation and its pathological effects are the major cause of several neurodegenerative diseases. In Huntington’s disease an elongated stretch of polyglutamines within the protein Huntingtin leads to increased aggregation propensity. This induces cellular defects, culminating in neuronal loss, but the connection between aggregation and toxicity remains to be established. Results To uncover cellular pathways relevant for intoxication we used genome-wide analyses in a yeast model system and identify fourteen genes that, if deleted, result in higher polyglutamine toxicity. Several of these genes, like UGO1, ATP15 and NFU1 encode mitochondrial proteins, implying that a challenged mitochondrial system may become dysfunctional during polyglutamine intoxication. We further employed microarrays to decipher the transcriptional response upon polyglutamine intoxication, which exposes an upregulation of genes involved in sulfur and iron metabolism and mitochondrial Fe-S cluster formation. Indeed, we find that in vivo iron concentrations are misbalanced and observe a reduction in the activity of the prominent Fe-S cluster containing protein aconitase. Like in other yeast strains with impaired mitochondria, non-fermentative growth is impossible after intoxication with the polyglutamine protein. NMR-based metabolic analyses reveal that mitochondrial metabolism is reduced, leading to accumulation of metabolic intermediates in polyglutamine-intoxicated cells. Conclusion These data show that damages to the mitochondrial system occur in polyglutamine intoxicated yeast cells and suggest an intricate connection between polyglutamine-induced toxicity, mitochondrial functionality and iron homeostasis in this model system.

  16. Mechanical analysis of a heat-shock induced developmental defect

    Science.gov (United States)

    Crews, Sarah M.; McCleery, W. Tyler; Hutson, M. Shane

    2014-03-01

    Embryonic development in Drosophila is a complex process involving coordinated movements of mechanically interacting tissues. Perturbing this system with a transient heat shock can result in a number of developmental defects. In particular, a heat shock applied during the earliest morphogenetic movements of gastrulation can lead to apparent recovery, but then subsequent morphogenetic failure 5-6 hours later during germ band retraction. The process of germ band retraction requires an intact amnioserosa - a single layered extra-embryonic epithelial tissue - and heat shock at gastrulation can induce the later opening of holes in the amnioserosa. These holes are highly correlated with failures of germ band retraction. These holes could be caused by a combination of mechanical weakness in the amnioserosa or local increases in mechanical stress. Here, we assess the role of mechanical stress using confocal imaging to compare cell and tissue morphology in the amnioserosa of normal and heat-shocked embryos and laser hole drilling to map the stress field around the times and locations at which heat-shock induced holes open.

  17. Impacts of reactor. Induced cladding defects on spent fuel storage

    International Nuclear Information System (INIS)

    Johnson, A.B.

    1978-01-01

    Defects arise in the fuel cladding on a small fraction of fuel rods during irradiation in water-cooled power reactors. Defects from mechanical damage in fuel handling and shipping have been almost negligible. No commercial water reactor fuel has yet been observed to develop defects while stored in spent fuel pools. In some pools, defective fuel is placed in closed canisters as it is removed from the reactor. However, hundreds of defective fuel bundles are stored in numerous pools on the same basis as intact fuel. Radioactive species carried into the pool from the reactor coolant must be dealt with by the pool purification system. However, additional radiation releases from the defective fuel during storage appear tu be minimal, with the possible exception of fuel discharged while the reactor is operating (CANDU fuel). Over approximately two decades, defective commercial fuel has been handled, stored, shipped and reprocessed. (author)

  18. Genetic defect causing familial Alzheimer's disease maps on chromosome 21

    Energy Technology Data Exchange (ETDEWEB)

    St. George-Hyslop, P.H.; Tanzi, R.E.; Polinsky, R.J.; Haines, J.L.; Nee, L.; Watkins, P.C.; Myers, R.H.; Feldman, R.G.; Pollen, D.; Drachman, D.; Growdon, J.

    1987-02-20

    Alzheimer's disease is a leading cause of morbidity and mortality among the elderly. Several families have been described in which Alzheimer's disease is caused by an autosomal dominant gene defect. The chromosomal location of this defective gene has been discovered by using genetic linkage to DNA markers on chromosome 21. The localization on chromosome 21 provides an explanation for the occurrence of Alzheimer's disease-like pathology in Down syndrome. Isolation and characterization of the gene at this locus may yield new insights into the nature of the defect causing familial Alzheimer's disease and possibly, into the etiology of all forms of Alzheimer's disease.

  19. Schizophrenia with the 22q11.2 deletion and additional genetic defects: case history.

    Science.gov (United States)

    Toyosima, M; Maekawa, M; Toyota, T; Iwayama, Y; Arai, M; Ichikawa, T; Miyashita, M; Arinami, T; Itokawa, M; Yoshikawa, T

    2011-09-01

    The 22q11.2 deletion is the most prominent known genetic risk factor for schizophrenia, but its penetrance is at most approximately 50% suggesting that additional risk factors are required for disease progression. We examined a woman with schizophrenia with this deletion for such risk factors. She had high plasma pentosidine levels ('carbonyl stress') and a frameshift mutation in the responsible gene, GLO1. She also had a constant exotropia, so we examined the PHOX2B gene associated with both schizophrenia and strabismus, and detected a 5-alanine deletion. We propose that the combination of these genetic defects may have exceeded the threshold for the manifestation of schizophrenia.

  20. Luminescence Properties of Surface Radiation-Induced Defects in Lithium Fluoride

    Science.gov (United States)

    Voitovich, A. P.; Kalinov, V. S.; Martynovich, E. F.; Novikov, A. N.; Runets, L. P.; Stupak, A. P.

    2013-11-01

    Luminescence and luminescence excitation spectra are recorded for surface radiation-induced defects in lithium fluoride at temperatures of 77 and 293 K. The presence of three bands with relatively small intensity differences is a distinctive feature of the excitation spectrum. These bands are found to belong to the same type of defects. The positions of the peaks and the widths of the absorption and luminescence bands for these defects are determined. The luminescence decay time is measured. All the measured characteristics of these surface defects differ from those of previously known defects induced by radiation in the bulk of the crystals. It is found that the luminescence of surface defects in an ensemble of nanocrystals with different orientations is not polarized. The number of anion vacancies in the surface defects is estimated using the polarization measurements. It is shown that radiative scattering distorts the intensity ratios of the luminescence excitation bands located in different spectral regions.

  1. Radiation induced defect flux behaviors at zirconium based component

    International Nuclear Information System (INIS)

    Choi, Sang Il; Kim, Ji Hyun; Kwon, Jun Hyun; Lee, Gyeong Geun

    2013-01-01

    In commercial reactor core, structure materials are located in high temperature and high pressure environment. Therefore, main concern of structure materials is corrosion and mechanical properties change than radiation effects on materials. However, radiation effects on materials become more important phenomena because research reactor condition is different from commercial reactor. The temperature is lower than 100 .deg. C and radiation dose is much higher than that of commercial reactor. Among the radiation effect on zirconium based metal, radiation induced growth (RIG), known as volume conservative distortion, is one of the most important phenomena. Recently, theoretical RIG modeling based on radiation damage theory (RDT) and balance equation are developed. However, these growth modeling have limited framework of single crystal and high temperature. To model theoretical RIG in research reactor, qualitative mechanism must be set up. Therefore, this paper intent is establishing defect flux mechanism of zirconium base metal in research reactor for RIG modeling. After than theoretical RIG work will be expanded to research reactor condition

  2. Genetic interactions between planar cell polarity genes cause diverse neural tube defects in mice

    Directory of Open Access Journals (Sweden)

    Jennifer N. Murdoch

    2014-10-01

    Full Text Available Neural tube defects (NTDs are among the commonest and most severe forms of developmental defect, characterized by disruption of the early embryonic events of central nervous system formation. NTDs have long been known to exhibit a strong genetic dependence, yet the identity of the genetic determinants remains largely undiscovered. Initiation of neural tube closure is disrupted in mice homozygous for mutations in planar cell polarity (PCP pathway genes, providing a strong link between NTDs and PCP signaling. Recently, missense gene variants have been identified in PCP genes in humans with NTDs, although the range of phenotypes is greater than in the mouse mutants. In addition, the sequence variants detected in affected humans are heterozygous, and can often be detected in unaffected individuals. It has been suggested that interactions between multiple heterozygous gene mutations cause the NTDs in humans. To determine the phenotypes produced in double heterozygotes, we bred mice with all three pairwise combinations of Vangl2Lp, ScribCrc and Celsr1Crsh mutations, the most intensively studied PCP mutants. The majority of double-mutant embryos had open NTDs, with the range of phenotypes including anencephaly and spina bifida, therefore reflecting the defects observed in humans. Strikingly, even on a uniform genetic background, variability in the penetrance and severity of the mutant phenotypes was observed between the different double-heterozygote combinations. Phenotypically, Celsr1Crsh;Vangl2Lp;ScribCrc triply heterozygous mutants were no more severe than doubly heterozygous or singly homozygous mutants. We propose that some of the variation between double-mutant phenotypes could be attributed to the nature of the protein disruption in each allele: whereas ScribCrc is a null mutant and produces no Scrib protein, Celsr1Crsh and Vangl2Lp homozygotes both express mutant proteins, consistent with dominant effects. The variable outcomes of these genetic

  3. Gamma-induced defect production in ZrO2-Y2O3 crystals with different defectiveness

    International Nuclear Information System (INIS)

    Ashurov, M.Kh.; Amonov, M.Z.; Rakov, A.F.

    2002-01-01

    Full text: The defectiveness degree of ZrO 2 -Y 2 O 3 crystals depends on stabilizer concentration. The work is aimed at study gamma-induced defect production in crystals with different concentration of stabilizer and defects generated by neutron irradiation. Absorption spectra were measured with Specord M-40. It was found, that after gamma-irradiation of as-grown crystals up to some dose the intensity of absorption band at 420 nm reaches the maximum level of saturation. The dose of saturation depends of the concentration of stabilizer. It means that gamma-radiation does not produce any additional defects of structure. The oxygen vacancies existing in as-grown crystals are filled by the radiation induced electrons. Since the number of oxygen vacancies depends on the stabilizer concentration, then all these vacancies can be occupied by electrons at different gamma-doses. In crystals pre-irradiated with different neutron fluences followed by gamma-irradiation, the intensity of absorption bands at 420 and 530 nm increases in two stages. The gamma-dose of the second stage beginning decreases as the neutron fluence grows. The first stage of the absorption increase is due to developing of vacancies existing in as-grown crystals. The second stage is caused by generation of additional vacancies as the result of non-radiative exciton decay near the existing structure damages. The decrease of the gamma-dose, when the second stage of vacancy accumulation begins, results from the neutron induced structure damage degree

  4. Effect of Concomitant Birth Defects and Genetic Anomalies on Infant Mortality in Tetralogy of Fallot.

    Science.gov (United States)

    Jernigan, Eric G; Strassle, Paula D; Stebbins, Rebecca C; Meyer, Robert E; Nelson, Jennifer S

    2017-08-15

    A substantial proportion of infants born with tetralogy of Fallot (TOF) die in infancy. A better understanding of the heterogeneity associated with TOF, including extracardiac malformations and chromosomal anomalies is vital to stratifying risk and optimizing outcomes during infancy. Using the North Carolina Birth Defects Monitoring Program, infants diagnosed with TOF and born between 2003 and 2012 were included. Kaplan-Meier survival curves were used to estimate cumulative 1-year mortality, stratified by the presence of concomitant birth defects (BDs) and chromosomal anomalies. Multivariable logistic regression was used to estimate the direct effect of each concomitant BD, after adjusting for all others. A total of 496 infants with TOF were included, and 15% (n = 76) died. The number of concomitant BD systems was significantly associated with the risk of death at 1-year, p < 0.0001. Specifically, the risk of mortality was 8% among infants with TOF with or without additional cardiac defects, 16% among infants with TOF and 1 extracardiac BD system, 19% among infants with 2 extracardiac BD systems, and 39% among infants with ≥ 3 extracardiac BD systems. After adjustment, concomitant eye and gastrointestinal defects were significantly associated increased with 1-year mortality, odds ratio 2.83 (95% confidence interval, 1.08-7.32) and odds ratio 4.43 (95% confidence interval, 1.57, 12.45), respectively. Infants with trisomy 13 or trisomy 18 were also significantly more likely to die, p < 0.0001. Both concomitant BDs and genetic anomalies increase the risk of mortality among infants with TOF. Future studies are needed to identify the underlying genetic and socioeconomic risk factors for high-risk TOF infants. Birth Defects Research 109:1154-1165, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Electrical Characterisation of electron beam exposure induced Defects in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Danga, Helga T., E-mail: helga.danga@up.ac.za; Auret, Francois D.; Coelho, Sergio M.M.; Diale, Mmantsae

    2016-01-01

    The defects introduced in epitaxially grown p-type silicon (Si) during electron beam exposure were electrically characterised using deep level transient spectroscopy (DLTS) and high resolution Laplace-DLTS. In this process, Si samples were first exposed to the conditions of electron beam deposition (EBD) without metal deposition. This is called electron beam exposure (EBE) herein. After 50 minutes of EBE, nickel (Ni) Schottky contacts were fabricated using the resistive deposition method. The defect level observed using the Ni contacts had an activation energy of H(0.55). This defect has an activation energy similar to that of the I-defect. The defect level is similar to that of the HB4, a boron related defect. DLTS depth profiling revealed that H(0.55) could be detected up to a depth of 0.8 μm below the junction. We found that exposing the samples to EBD conditions without metal deposition introduced a defect which was not introduced by the EBD method. We also observed that the damage caused by EBE extended deeper into the material compared to that caused by EBD.

  6. Atrioventricular canal defect and associated genetic disorders: new insights into polydactyly syndromes

    Directory of Open Access Journals (Sweden)

    M. Cristina Digilio

    2011-07-01

    Full Text Available Atrioventricular canal defect (AVCD is a common congenital heart defect (CHD, representing 7.4% of all cardiac malformations, considered secondary to an extracellular matrix anomaly. The AVCD is associated with extracardiac defects in about 75% of the cases. In this review we analyzed different syndromic AVCDs, in particular those associated with polydactyly disorders, which show remarkable genotype-phenotype correlations. Chromo - some imbalances more frequently associated with AVCD include Down syndrome, deletion 8p23 and deletion 3p25, while mendelian disorders include Noonan syndrome and related RASopathies, several polydactyly syndromes, CHARGE and 3C (cranio-cerebello-cardiac syndrome. The complete form of AVCD is prevalent in patients with chromosomal imbalances. Additional cardiac defects are found in patients affected by chromosomal imbalances different from Down syndrome. Left-sided obstructive lesions are prevalently found in patients with RASopathies. Patients with deletion 8p23 often display AVCD with tetralogy of Fallot or with pulmonary valve stenosis. Tetralogy of Fallot is the only additional cardiac defect found in patients with Down syndrome and AVCD. On the other hand, the association of AVCD and tetralogy of Fallot is also quite characteristic of CHARGE and 3C syndromes. Heterotaxia defects, including common atrium and anomalous pulmonary venous return, occur in patients with AVCD associated with polydactyly syndromes (Ellis-van Creveld, short rib polydactyly, oral-facial-digital, Bardet-Biedl, and Smith-Lemli-Opitz syndromes. The initial clinical evidence of anatomic similarities between AVCD and heterotaxia in polydactyly syndromes was corroborated and explained by experimental studies in transgenic mice. These investigations have suggested the involvement of the Sonic Hedgehog pathway in syndromes with postaxial polydactyly and heterotaxia, and ciliary dysfunction was detected as pathomechanism for these disorders

  7. Radiation induced genetic damage in Aspergillus nidulans

    International Nuclear Information System (INIS)

    Georgiou, J.T.

    1984-01-01

    The mechanism by which ionizing radiation induces genetic damage in haploid and diploid conidia of Aspergillus nidulans was investigated. Although the linear dose-response curves obtained following low LET irradiation implied a 'single-hit' action of radiation, high LET radiations were much more efficient than low LET radiations, which suggests the involvement of a multiple target system. It was found that the RBE values for non-disjunction and mitotic crossing-over were very different. Unlike mitotic crossing-over, the RBE values for non-disjunction were much greater than for cell killing. This suggests that non-disjunction is a particularly sensitive genetical endpoint that is brought about by damage to a small, probably non-DNA target. Radiosensitisers were used to study whether radiation acts at the level of the DNA or some other cellular component. The sensitisation to electrons and/or X-rays by oxygen, and two nitroimidazoles (metronidazole and misonidazole) was examined for radiation induced non-disjunction, mitotic crossing-over, gene conversion, point mutation and cell killing. It was found that these compounds sensitised the cells considerably more to genetic damage than to cell killing. (author)

  8. N+ ion-implantation-induced defects in ZnO studied with a slow positron beam

    International Nuclear Information System (INIS)

    Chen, Z Q; Sekiguchi, T; Yuan, X L; Maekawa, M; Kawasuso, A

    2004-01-01

    Undoped ZnO single crystals were implanted with multiple-energy N + ions ranging from 50 to 380 keV with doses from 10 12 to 10 14 cm -2 . Positron annihilation measurements show that vacancy defects are introduced in the implanted layers. The concentration of the vacancy defects increases with increasing ion dose. The annealing behaviour of the defects can be divided into four stages, which correspond to the formation and recovery of large vacancy clusters and the formation and disappearance of vacancy-impurity complexes, respectively. All the implantation-induced defects are removed by annealing at 1200 deg. C. Cathodoluminescence measurements show that the ion-implantation-induced defects act as nonradiative recombination centres to suppress the ultraviolet (UV) emission. After annealing, these defects disappear gradually and the UV emission reappears, which coincides with positron annihilation measurements. Hall measurements reveal that after N + implantation, the ZnO layer still shows n-type conductivity

  9. Implantation processing of Si: A unified approach to understanding ion-induced defects and their impact

    International Nuclear Information System (INIS)

    Holland, O.W.; Roth, E.G.

    1997-05-01

    A model is presented to account for the effects of ion-induced defects during implantation processing of Si. It will be shown that processing is quite generally affected by the presence of defect excesses rather than the total number of defects. a defect is considered excess if it represents a surplus locally of one defect type over its compliment. Processing spanning a wide range of implantation conditions will be presented to demonstrate that the majority of the total defects played little or no role in the process. This is a direct result of the ease with which the spatially correlated Frenkel pairs recombine either dynamically or during a post-implantation annealing. Based upon this model, a method will be demonstrated for manipulating or engineering the excess defects to modify their effects. In particular high-energy, self-ions are shown to inject vacancies into a boron implanted region resulting in suppression of transient enhanced diffusion of the dopant

  10. Ion-irradiation-induced defects in bundles of carbon nanotubes

    International Nuclear Information System (INIS)

    Salonen, E.; Krasheninnikov, A.V.; Nordlund, K.

    2002-01-01

    We study the structure and formation yields of atomic-scale defects produced by low-dose Ar ion irradiation in bundles of single-wall carbon nanotubes. For this, we employ empirical potential molecular dynamics and simulate ion impact events over an energy range of 100-1000 eV. We show that the most common defects produced at all energies are vacancies on nanotube walls, which at low temperatures are metastable but long-lived defects. We further calculate the spatial distribution of the defects, which proved to be highly non-uniform. We also show that ion irradiation gives rise to the formations of inter-tube covalent bonds mediated by carbon recoils and nanotube lattice distortions due to dangling bond saturation. The number of inter-tube links, as well as the overall damage, linearly grows with the energy of incident ions

  11. Defect-induced ferromagnetism in semiconductors: A controllable approach by particle irradiation

    International Nuclear Information System (INIS)

    Zhou, Shengqiang

    2014-01-01

    Making semiconductors ferromagnetic has been a long dream. One approach is to dope semiconductors with transition metals (TM). TM ions act as local moments and they couple with free carriers to develop collective magnetism. However, there are no fundamental reasons against the possibility of local moment formation from localized sp states. Recently, ferromagnetism was observed in nonmagnetically doped, but defective semiconductors or insulators including ZnO and TiO 2 . This kind of observation challenges the conventional understanding of ferromagnetism. Often the defect-induced ferromagnetism has been observed in samples prepared under non-optimized condition, i.e. by accident or by mistake. Therefore, in this field theory goes much ahead of experimental investigation. To understand the mechanism of the defect-induced ferromagnetism, one needs a better controlled method to create defects in the crystalline materials. As a nonequilibrium and reproducible approach of inducing defects, ion irradiation provides such a possibility. Energetic ions displace atoms from their equilibrium lattice sites, thus creating mainly vacancies, interstitials or antisites. The amount and the distribution of defects can be controlled by the ion fluence and energy. By ion irradiation, we have generated defect-induced ferromagnetism in ZnO, TiO 2 and SiC. In this short review, we also summarize some results by other groups using energetic ions to introduce defects, and thereby magnetism in various materials. Ion irradiation combined with proper characterizations of defects could allow us to clarify the local magnetic moments and the coupling mechanism in defective semiconductors. Otherwise we may have to build a new paradigm to understand the defect-induced ferromagnetism

  12. Hardening in AlN induced by point defects

    International Nuclear Information System (INIS)

    Suematsu, H.; Mitchell, T.E.; Iseki, T.; Yano, T.

    1991-01-01

    Pressureless-sintered AIN was neutron irradiated and the hardness change was examined by Vickers indentation. The hardness was increased by irradiation. When the samples were annealed at high temperature, the hardness gradually decreased. Length was also found to increase and to change in the same way as the hardness. A considerable density of dislocation loops still remained, even after the hardness completely recovered to the value of the unirradiated sample. Thus, it is concluded that the hardening in AIN is caused by isolated point defects and small clusters of point defects, rather than by dislocation loops. Hardness was found to increase in proportion to the length change. If the length change is assumed to be proportional to the point defect density, then the curve could be fitted qualitatively to that predicted by models of solution hardening in metals. Furthermore, the curves for three samples irradiated at different temperatures and fluences are identical. There should be different kinds of defect clusters in samples irradiated at different conditions, e.g., the fraction of single point defects is the highest in the sample irradiated at the lowest temperature. Thus, hardening is insensitive to the kind of defects remaining in the sample and is influenced only by those which contribute to length change

  13. Genetic Defects Underlie the Non-syndromic Autosomal Recessive Intellectual Disability (NS-ARID

    Directory of Open Access Journals (Sweden)

    Saleha Shamim

    2017-05-01

    Full Text Available Intellectual disability (ID is a neurodevelopmental disorder which appears frequently as the result of genetic mutations and may be syndromic (S-ID or non-syndromic (NS-ID. ID causes an important economic burden, for patient's family, health systems, and society. Identifying genes that cause S-ID can easily be evaluated due to the clinical symptoms or physical anomalies. However, in the case of NS-ID due to the absence of co-morbid features, the latest molecular genetic techniques can be used to understand the genetic defects that underlie it. Recent studies have shown that non-syndromic autosomal recessive (NS-ARID is extremely heterogeneous and contributes much more than X-linked ID. However, very little is known about the genes and loci involved in NS-ARID relative to X-linked ID, and whose complete genetic etiology remains obscure. In this review article, the known genetic etiology of NS-ARID and possible relationships between genes and the associated molecular pathways of their encoded proteins has been reviewed which will enhance our understanding about the underlying genes and mechanisms in NS-ARID.

  14. Change of elastic constants induced by point defects in hop crystals

    International Nuclear Information System (INIS)

    Tome, C.

    1979-10-01

    An approximate model is developed to calculate the change of elastic constants induced by point defects in hcp metals, supposed the defect configuration is known. General expressions relating the change of elastic moduli to the final atomic coordinates and to the defect force field are derived using the specific symmetry of the defect. Explicit calculations are done for Mg. The predicted change of elastic moduli turns out to be negative for vacancies and trigonal interstitials while for hexagonal interstitials a positive change is predicted. Compatibility with experimental data would suggest that the trigonal configuration is the stable one. (author)

  15. Defect-induced transitions in synchronous asymmetric exclusion processes

    International Nuclear Information System (INIS)

    Liu Mingzhe; Wang Ruili; Jiang Rui; Hu Maobin; Gao Yang

    2009-01-01

    The effects of a single local defect in synchronous asymmetric exclusion processes are investigated via theoretical analysis and Monte Carlo simulations. Our theoretical analysis shows that there are four possible stationary phases, i.e., the (low density, low density), (low density, high density), (high density, low density) and (high density, high density) in the system. In the (high density, low density) phase, the system can reach a maximal current which is determined by the local defect, but independent of boundary conditions. A phenomenological domain wall approach is developed to predict dynamic behavior at phase boundaries. The effects of defective hopping probability p on density profiles and currents are investigated. Our investigation shows that the value of p determines phase transitions when entrance rate α and exit rate β are fixed. Density profiles and currents obtained from theoretical calculations are in agreement with Monte Carlo simulations

  16. Insulating Behavior in Graphene with Irradiation-induced Lattice Defects

    Science.gov (United States)

    Chen, Jian-Hao; Williams, Ellen; Fuhrer, Michael

    2010-03-01

    We irradiated cleaned graphene on silicon dioxide in ultra-high vacuum with low energy inert gas ions to produce lattice defects [1], and investigated in detail the transition from metallic to insulating temperature dependence of the conductivity as a function of defect density. We measured the low field magnetoresistance and temperature-dependent resistivity in situ and find that weak localization can only account for a small correction of the resistivity increase with decreasing temperature. We will discuss possible origins of the insulating temperature dependent resistivity in defected graphene in light of our recent experiments. [4pt] [1] Jian-Hao Chen, W. G. Cullen, C. Jang, M. S. Fuhrer, E. D. Williams, PRL 102, 236805 (2009)

  17. Ionization-induced rearrangement of defects in silicon

    International Nuclear Information System (INIS)

    Vinetskij, V.L.; Manojlo, M.A.; Matvijchuk, A.S.; Strikha, V.I.; Kholodar', G.A.

    1988-01-01

    Ionizing factor effect on defect rearrangement in silicon including centers with deep local electron levels in the p-n-transition region is considered. Deep center parameters were determined using non-steady-state capacity spectroscopy of deep levels (NCDLS) method. NCDLS spectrum measurement was performed using source p + -n - diodes and after their irradiation with 15 keV energy electrons or laser pulses. It is ascertained that in silicon samples containing point defect clusters defect rearrangement under ionizing factor effect takes place, i.e. deep level spectra are changed. This mechanism is efficient in case of silicon irradiation with subthreshold energy photons and electrons and can cause degradation of silicon semiconducting structures

  18. Classification of Atrial Septal Defect and Ventricular Septal Defect with Documented Hemodynamic Parameters via Cardiac Catheterization by Genetic Algorithms and Multi-Layered Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Mustafa Yıldız

    2012-08-01

    Full Text Available Introduction: We aimed to develop a classification method to discriminate ventricular septal defect and atrial septal defect by using severalhemodynamic parameters.Patients and Methods: Forty three patients (30 atrial septal defect, 13 ventricular septal defect; 26 female, 17 male with documentedhemodynamic parameters via cardiac catheterization are included to study. Such parameters as blood pressure values of different areas,gender, age and Qp/Qs ratios are used for classification. Parameters, we used in classification are determined by divergence analysismethod. Those parameters are; i pulmonary artery diastolic pressure, ii Qp/Qs ratio, iii right atrium pressure, iv age, v pulmonary arterysystolic pressure, vi left ventricular sistolic pressure, vii aorta mean pressure, viii left ventricular diastolic pressure, ix aorta diastolicpressure, x aorta systolic pressure. Those parameters detected from our study population, are uploaded to multi-layered artificial neuralnetwork and the network was trained by genetic algorithm.Results: Trained cluster consists of 14 factors (7 atrial septal defect and 7 ventricular septal defect. Overall success ratio is 79.2%, andwith a proper instruction of artificial neural network this ratio increases up to 89%.Conclusion: Parameters, belonging to artificial neural network, which are needed to be detected by the investigator in classical methods,can easily be detected with the help of genetic algorithms. During the instruction of artificial neural network by genetic algorithms, boththe topology of network and factors of network can be determined. During the test stage, elements, not included in instruction cluster, areassumed as in test cluster, and as a result of this study, we observed that multi-layered artificial neural network can be instructed properly,and neural network is a successful method for aimed classification.

  19. Molecular marker studies in riverine buffaloes, for characterization and diagnosis of genetic defects

    International Nuclear Information System (INIS)

    Yadav, B.R.

    2005-01-01

    The buffalo is probably the last livestock species to have been domesticated, with many genetic, physiological and behavioural traits not yet well understood. Molecular markers have been used for characterizing animals and breeds, diagnosing diseases and identifying anatomical and physiological anomalies. RFLP studies showed low heterozygosity, but genomic and oligonucleotide probes showed species-specific bands useful for identification of carcass or other unknown samples. Use of RAPD revealed band frequencies, band sharing frequencies, genetic distances, and genetic and identity indexes in different breeds. Bovine microsatellite primers indicate that 70.9% of bovine loci were conserved in buffalo. Allele numbers, sizes, frequencies, heterozygosity and polymorphism information content showed breed-specific patterns. Different marker types - genomic and oligonucleotide probes, RAPD and microsatellites - are useful in parent identification. Individual specific DNA fingerprinting techniques were applied with twin-born animal (XX/XY) chimerism, sex identification, anatomically defective and XO individuals. Molecular markers are a potential tool for geneticists and breeders to evaluate existing germplasm and to manipulate it to develop character-specific strains and to provide the basis for effective genetic conservation. (author)

  20. Induced defects in neutron irradiated GaN single crystals

    International Nuclear Information System (INIS)

    Park, I. W.; Koh, E. K.; Kim, Y. M.; Choh, S. H.; Park, S. S.; Kim, B. G.; Sohn, J. M.

    2005-01-01

    The local structure of defects in undoped, Si-doped, and neutron irradiated free standing GaN bulk crystals, grown by hydride vapor phase epitaxy, has been investigated by employing Raman scattering and cathodoluminescence. The GaN samples were irradiated to a dose of 2 x 10 17 neutrons in an atomic reactor at Korea Atomic Energy Research Institute. There was no appreciable change in the Raman spectra for undoped GaN samples before and after neutron irradiation. However, a forbidden transition, A 1 (TO) mode, appeared for a neutron irradiated Si-doped GaN crystal. Cathodoluminescence spectrum for the neutron irradiated Si-doped GaN crystal became much more broadened than that for the unirradiated one. The experimental results reveal the generation of defects with locally deformed structure in the wurtzite Si-doped GaN single crystal

  1. Segregation of Spontaneous and Training Induced Recovery from Visual Field Defects in Subacute Stroke Patients

    Directory of Open Access Journals (Sweden)

    Douwe P. Bergsma

    2017-12-01

    Full Text Available Whether rehabilitation after stroke profits from an early start is difficult to establish as the contributions of spontaneous recovery and treatment are difficult to tease apart. Here, we use a novel training design to dissociate these components for visual rehabilitation of subacute stroke patients with visual field defects such as hemianopia. Visual discrimination training was started within 6 weeks after stroke in 17 patients. Spontaneous and training-induced recoveries were distinguished by training one-half of the defect for 8 weeks, while monitoring spontaneous recovery in the other (control half of the defect. Next, trained and control regions were swapped, and training continued for another 8 weeks. The same paradigm was also applied to seven chronic patients for whom spontaneous recovery can be excluded and changes in the control half of the defect point to a spillover effect of training. In both groups, field stability was assessed during a no-intervention period. Defect reduction was significantly greater in the trained part of the defect than in the simultaneously untrained part of the defect irrespective of training onset (p = 0.001. In subacute patients, training contributed about twice as much to their defect reduction as the spontaneous recovery. Goal Attainment Scores were significantly and positively correlated with the total defect reduction (p = 0.01, percentage increase reading speed was significantly and positively correlated with the defect reduction induced by training (epoch 1: p = 0.0044; epoch 2: p = 0.023. Visual training adds significantly to the spontaneous recovery of visual field defects, both during training in the early and the chronic stroke phase. However, field recovery as a result of training in this subacute phase was as large as in the chronic phase. This suggests that patients benefited primarily of early onset training by gaining access to a larger visual field sooner.

  2. Genetic and environmental effects on a meat spotting defect in seasoned dry-cured ham

    Directory of Open Access Journals (Sweden)

    Giulio Pagnacco

    2011-01-01

    Full Text Available Purpose of this investigation was to determine the nature of a visible spotting defect on the slice of dry-cured ham and assess environmental and genetic causes of this frequent problem. A group of 233 pigs from commercial cross-breeding lines, progeny of ten boars and forty seven sows, was raised in a single herd to obtain the “Italian Heavy Pig”, typically slaughtered at 160 ± 10 kg live weight and older than 9 months of age. A quality evaluation of their right dry-cured hams, seasoned according to the Parma P.D.O. protocol, was undertaken. Each ham was cross-sectioned to obtain a slice of Semimembranosus, Semitendinosus and Biceps Femoris muscles. The focused phenotype was the presence/absence of brownish spots in these muscles, which represent a remarkable meat defect with strong impact on the final sale price. Environmental and management factors were considered in order to evaluate variability related to the phenotype. Animals were raised on two different flooring types (concrete and slatted floor and a Vitamin C diet was also supplemented in the last 45 days before slaughtering to half of the animals. While the pre-planned environmental effects did not show any significant contribution to the total variability of the phenotype, the genetic analysis showed a near to zero value for heritability with a consistent 0.32 repeatability. The proportion of the total phenotypic variance was explained by an important dominance genetic component (0.26 indicating that the technological seasoning process may play a secondary role on the expression of this phenotype.

  3. Defect-induced magnetic structure of CuMnSb

    Czech Academy of Sciences Publication Activity Database

    Máca, František; Kudrnovský, Josef; Drchal, Václav; Turek, I.; Stelmakhovych, O.; Beran, Přemysl; Llobet, A.; Martí, Xavier

    2016-01-01

    Roč. 94, č. 9 (2016), 1-9, č. článku 094407. ISSN 2469-9950 R&D Projects: GA ČR GB14-37427G Institutional support: RVO:68378271 ; RVO:61389005 Keywords : CuMnSb * electronic structure * defects * magnetic order * ab initio calculations * neutron diffraction analysis Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.836, year: 2016

  4. Effect of interaction between irradiation-induced defects and intrinsic defects in the pinning improvement of neutron irradiated YBaCuO sample

    International Nuclear Information System (INIS)

    Topal, Ugur; Sozeri, Huseyin; Yavuz, Hasbi

    2004-01-01

    Interaction between the intrinsic (native) defects and the irradiation-induced defects created by neutron irradiation was examined for the YBCO sample. For this purpose, non-superconducting Y-211 phase was included to the Y-123 samples at different contents as a source of large pinning center. The critical current density enhancement with the irradiation for these samples were analysed and then the role of defects on pinning improvement was discussed

  5. Effect of interaction between irradiation-induced defects and intrinsic defects in the pinning improvement of neutron irradiated YBaCuO sample

    Energy Technology Data Exchange (ETDEWEB)

    Topal, Ugur; Sozeri, Huseyin; Yavuz, Hasbi

    2004-08-01

    Interaction between the intrinsic (native) defects and the irradiation-induced defects created by neutron irradiation was examined for the YBCO sample. For this purpose, non-superconducting Y-211 phase was included to the Y-123 samples at different contents as a source of large pinning center. The critical current density enhancement with the irradiation for these samples were analysed and then the role of defects on pinning improvement was discussed.

  6. Effect of radiation-induced substrate defects on microstrip gas chamber gain behaviour

    International Nuclear Information System (INIS)

    Pallares, A.; Brom, J.M.; Bergdolt, A.M.; Coffin, J.; Eberle, H.; Sigward, M.H.; Fontaine, J.C.; Barthe, S.; Schunck, J.P.

    1998-01-01

    The aim of this work was to quantify the influence of radiation-induced substrate defects on microstrip gas chamber (MSGC) gain behaviour. The first part of this paper focuses on radiation effects on a typical MSGC substrate: Desag D263 glass. Defect generation was studied for Desag D263 with pure silica (Suprasil 1) as a reference. We studied the evolution of defect concentration with respect to accumulated doses up to 480 kGy. Annealing studies of defects in Desag D263 were also performed. In the second part, the radiation sensitivity of Desag D263 glass has been linked to the behaviour of the detector under irradiation. Comparative gain measurements were taken before and after substrate irradiation at 10 and 80 kGy the minimal dose received during LHC operation and the dose for which defect density is maximum (respectively). (orig.)

  7. Effect of radiation-induced substrate defects on microstrip gas chamber gain behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Pallares, A.; Brom, J.M.; Bergdolt, A.M.; Coffin, J.; Eberle, H.; Sigward, M.H. [Institute de Recherches Subatomiques, 67 - Strasbourg (France); Fontaine, J.C. [Universite de Haute Alsace, GRPHE, 61 rue Albert Camus, 68093 Mulhouse Cedex (France); Barthe, S.; Schunck, J.P. [Laboratoire PHASE (UPR 292 du CNRS), 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 2 (France)

    1998-08-01

    The aim of this work was to quantify the influence of radiation-induced substrate defects on microstrip gas chamber (MSGC) gain behaviour. The first part of this paper focuses on radiation effects on a typical MSGC substrate: Desag D263 glass. Defect generation was studied for Desag D263 with pure silica (Suprasil 1) as a reference. We studied the evolution of defect concentration with respect to accumulated doses up to 480 kGy. Annealing studies of defects in Desag D263 were also performed. In the second part, the radiation sensitivity of Desag D263 glass has been linked to the behaviour of the detector under irradiation. Comparative gain measurements were taken before and after substrate irradiation at 10 and 80 kGy the minimal dose received during LHC operation and the dose for which defect density is maximum (respectively). (orig.) 26 refs.

  8. Proton irradiation induced defects in Cd and Zn doped InP

    International Nuclear Information System (INIS)

    Rybicki, G.C.; Williams, W.S.

    1993-01-01

    Proton irradiation induced defects in Zn and Cd doped InP have been studied by deep level transient spectroscopy, (DLTS). After 2 MeV proton irradiation the defects H4 and H5 were observed in lightly Zn doped InP, while the defects H3 and H5 were observed in more heavily Zn and Cd doped InP. The defect properties were not affected by the substitution of Cd for Zn, but the introduction rate of H5 was lower in Cd doped InP. The annealing rate of defects was also higher in Cd doped InP. The use of Cd doped InP may thus result in an InP solar cell with even greater radiation resistance

  9. Sorafenib-induced defective autophagy promotes cell death by necroptosis

    OpenAIRE

    Kharaziha, Pedram; Chioureas, Dimitris; Baltatzis, George; Fonseca, Pedro; Rodriguez, Patricia; Gogvadze, Vladimir; Lennartsson, Lena; Bj?rklund, Ann-Charlotte; Zhivotovsky, Boris; Grand?r, Dan; Egevad, Lars; Nilsson, Sten; Panaretakis, Theocharis

    2015-01-01

    Autophagy is one of the main cytoprotective mechanisms that cancer cells deploy to withstand the cytotoxic stress and survive the lethal damage induced by anti-cancer drugs. However, under specific conditions, autophagy may, directly or indirectly, induce cell death. In our study, treatment of the Atg5-deficient DU145 prostate cancer cells, with the multi-tyrosine kinase inhibitor, sorafenib, induces mitochondrial damage, autophagy and cell death. Molecular inhibition of autophagy by silencin...

  10. Radiation-induced defects in As-Sb-S glass

    International Nuclear Information System (INIS)

    Balitska, V; Shpotyuk, Ya; Filipecki, J; Shpotyuk, O

    2010-01-01

    Defect-related instability was studied in γ-irradiated (As 2 S 3 ) 1-x (Sb 2 S 3 ) x glasses (x = 0, 0.1, 0.2 and 0.3) using positron annihilation lifetime spectroscopy treated within high-measurement statistics. The observed decrease in average positron lifetime in the studied glasses is explained as a renovation of destroyed covalent chemical bonds after irradiation. This process is governed by monomolecular relaxation kinetics, being described in the framework of universal configuration-coordinate model.

  11. Radiation-induced defects in As-Sb-S glass

    Energy Technology Data Exchange (ETDEWEB)

    Balitska, V; Shpotyuk, Ya; Filipecki, J; Shpotyuk, O, E-mail: shpotyuk@novas.lviv.ua

    2010-11-15

    Defect-related instability was studied in {gamma}-irradiated (As{sub 2}S{sub 3}){sub 1-x}(Sb{sub 2}S{sub 3}){sub x} glasses (x = 0, 0.1, 0.2 and 0.3) using positron annihilation lifetime spectroscopy treated within high-measurement statistics. The observed decrease in average positron lifetime in the studied glasses is explained as a renovation of destroyed covalent chemical bonds after irradiation. This process is governed by monomolecular relaxation kinetics, being described in the framework of universal configuration-coordinate model.

  12. Annealing of radiation-induced defects in silicon in a simplified phenomenological model

    International Nuclear Information System (INIS)

    Lazanu, S.; Lazanu, I.

    2001-01-01

    The concentration of primary radiation-induced defects has been previously estimated considering both the explicit mechanisms of the primary interaction between the incoming particle and the nuclei of the semiconductor lattice, and the recoil energy partition between ionisation and displacements, in the frame of the Lindhard theory. The primary displacement defects are vacancies and interstitials that are essentially unstable in silicon. They interact via migration, recombination, annihilation or produce other defects. In the present work, the time evolution of the concentration of defects induced by pions in medium and high resistivity silicon for detectors is modelled, after irradiation. In some approximations, the differential equations representing the time evolution processes could be decoupled. The theoretical equations so obtained are solved analytically in some particular cases, with one free parameter, for a wide range of particle fluences and/or for a wide energy range of incident particles, for different temperatures; the corresponding stationary solutions are also presented

  13. Recurrent candidiasis and early-onset gastric cancer in a patient with a genetically defined partial MYD88 defect.

    Science.gov (United States)

    Vogelaar, Ingrid P; Ligtenberg, Marjolijn J L; van der Post, Rachel S; de Voer, Richarda M; Kets, C Marleen; Jansen, Trees J G; Jacobs, Liesbeth; Schreibelt, Gerty; de Vries, I Jolanda M; Netea, Mihai G; Hoogerbrugge, Nicoline

    2016-04-01

    Gastric cancer is caused by both genetic and environmental factors. A woman who suffered from recurrent candidiasis throughout her life developed diffuse-type gastric cancer at the age of 23 years. Using whole-exome sequencing we identified a germline homozygous missense variant in MYD88. Immunological assays on peripheral blood mononuclear cells revealed an impaired immune response upon stimulation with Candida albicans, characterized by a defective production of the cytokine interleukin-17. Our data suggest that a genetic defect in MYD88 results in an impaired immune response and may increase gastric cancer risk.

  14. Shp2 knockdown and Noonan/LEOPARD mutant Shp2-induced gastrulation defects.

    Directory of Open Access Journals (Sweden)

    Chris Jopling

    2007-12-01

    Full Text Available Shp2 is a cytoplasmic protein-tyrosine phosphatase that is essential for normal development. Activating and inactivating mutations have been identified in humans to cause the related Noonan and LEOPARD syndromes, respectively. The cell biological cause of these syndromes remains to be determined. We have used the zebrafish to assess the role of Shp2 in early development. Here, we report that morpholino-mediated knockdown of Shp2 in zebrafish resulted in defects during gastrulation. Cell tracing experiments demonstrated that Shp2 knockdown induced defects in convergence and extension cell movements. In situ hybridization using a panel of markers indicated that cell fate was not affected by Shp2 knock down. The Shp2 knockdown-induced defects were rescued by active Fyn and Yes and by active RhoA. We generated mutants of Shp2 with mutations that were identified in human patients with Noonan or LEOPARD Syndrome and established that Noonan Shp2 was activated and LEOPARD Shp2 lacked catalytic protein-tyrosine phosphatase activity. Expression of Noonan or LEOPARD mutant Shp2 in zebrafish embryos induced convergence and extension cell movement defects without affecting cell fate. Moreover, these embryos displayed craniofacial and cardiac defects, reminiscent of human symptoms. Noonan and LEOPARD mutant Shp2s were not additive nor synergistic, consistent with the mutant Shp2s having activating and inactivating roles in the same signaling pathway. Our results demonstrate that Shp2 is required for normal convergence and extension cell movements during gastrulation and that Src family kinases and RhoA were downstream of Shp2. Expression of Noonan or LEOPARD Shp2 phenocopied the craniofacial and cardiac defects of human patients. The finding that defective Shp2 signaling induced cell movement defects as early as gastrulation may have implications for the monitoring and diagnosis of Noonan and LEOPARD syndrome.

  15. Shock-induced spall in copper: the effects of anisotropy, temperature, loading pulse and defect

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Shengnian [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; An, Qi [Los Alamos National Laboratory; Han, Li - Bo [USTC

    2009-07-28

    Shock-induced spall in Cu is investigated with molecular dynamics simulations. We examine spallation in initially perfect crystals and defective solids with grain boundaries (columnar bicrystals), stacking faults or vacancies, as well as the effect of temperature and loading pulses. Spall in single crystal Cu is anisotropic, and defects and high temperature may reduce the spall strength. Taylor-wave (triangular shock-release wave) loading is explored in comparison with square wave shock loading.

  16. Origin of the defects-induced ferromagnetism in un-doped ZnO single crystals

    Science.gov (United States)

    Zhan, Peng; Xie, Zheng; Li, Zhengcao; Wang, Weipeng; Zhang, Zhengjun; Li, Zhuoxin; Cheng, Guodong; Zhang, Peng; Wang, Baoyi; Cao, Xingzhong

    2013-02-01

    We clarified, in this Letter, that in un-doped ZnO single crystals after thermal annealing in flowing argon, the defects-induced room-temperature ferromagnetism was originated from the surface defects and specifically, from singly occupied oxygen vacancies denoted as F+, by the optical and electrical properties measurements as well as positron annihilation analysis. In addition, a positive linear relationship was observed between the ferromagnetism and the F+ concentration, which is in support with the above clarification.

  17. What can we learn from Raman Spectroscopy on irradiation-induced defects in UO2?

    International Nuclear Information System (INIS)

    Desgranges, L.; Martin, Ph.; Simon, P.; Guimbretiere, G.; Baldinozzi, G.

    2014-01-01

    Recent results on irradiated UO 2 by Raman spectroscopy evidenced Raman lines that are characteristic of irradiation-induced defects. Three main mechanisms are identified to explain their origin: resonant Raman, formation of new molecular entities, or breakdown in symmetry. Arguments are given to consider breakdown in symmetry as the predominant mechanism. A tentative description of the defects at the origin of this symmetry breakdown is proposed in terms of coordination polyhedrons of uranium. This discussion led us to consider that the Raman defect modes could be related to area with different stoichiometry. (authors)

  18. Kinetic model for electric-field induced point defect redistribution near semiconductor surfaces

    Science.gov (United States)

    Gorai, Prashun; Seebauer, Edmund G.

    2014-07-01

    The spatial distribution of point defects near semiconductor surfaces affects the efficiency of devices. Near-surface band bending generates electric fields that influence the spatial redistribution of charged mobile defects that exchange infrequently with the lattice, as recently demonstrated for pile-up of isotopic oxygen near rutile TiO2 (110). The present work derives a mathematical model to describe such redistribution and establishes its temporal dependence on defect injection rate and band bending. The model shows that band bending of only a few meV induces significant redistribution, and that the direction of the electric field governs formation of either a valley or a pile-up.

  19. Kinetic model for electric-field induced point defect redistribution near semiconductor surfaces

    International Nuclear Information System (INIS)

    Gorai, Prashun; Seebauer, Edmund G.

    2014-01-01

    The spatial distribution of point defects near semiconductor surfaces affects the efficiency of devices. Near-surface band bending generates electric fields that influence the spatial redistribution of charged mobile defects that exchange infrequently with the lattice, as recently demonstrated for pile-up of isotopic oxygen near rutile TiO 2 (110). The present work derives a mathematical model to describe such redistribution and establishes its temporal dependence on defect injection rate and band bending. The model shows that band bending of only a few meV induces significant redistribution, and that the direction of the electric field governs formation of either a valley or a pile-up.

  20. Simulation of ion-beam induced defects in cuprate superconductors

    International Nuclear Information System (INIS)

    Dineva, M.; Marksteiner, M.; Lang, W.

    2005-01-01

    Full text: Heavy-ion irradiation of cuprate superconductors is well known to produce columnar defect tracks along which magnetic vortices can be pinned. Hence, this effect has a large potential for practical applications and can enhance the critical current of the high-temperature superconducting materials. On the other hand, little work has been devoted to light-ion irradiation of the new superconductors. Our previous experimental results have indicated a systematic change of electric transport properties when irradiating YBa 2 Cu 3 O 7 (YBCO) with 75 KEXV He + ions. The purpose of the present study is the investigation of the ion-target interactions with computer simulation programs based on the binary collision approximation. The program package SRIM (Stopping and Range of Ions in Matter) is widely used to simulate the impact of energetic ions (10 eV to 2 GeV) on a solid target using a quantum mechanical treatment of ion-atom collisions under the assumption of an unstructured target material. A similar program, MARLOWE, includes the exact crystalline structure of the target and, thus, is able to calculate ion channeling effects and angle dependences. Detailed results of the penetration range of ions into YBCO, scattering cascades, creation of vacancies and interstitials, are reported for various kinds of ions. One of the central results is that light ions with energy of about 80 KEXV can penetrate through thin films of the cuprate superconductors and create point defects, mainly by oxygen displacement. (author)

  1. Exercise-induced thallium-201 myocardial perfusion defects in angina pectoris without significant coronary artery stenosis

    International Nuclear Information System (INIS)

    Nakazato, Masayasu; Maruoka, Yuji; Sunagawa, Osahiko; Kinjo, Kunihiko; Tomori, Masayuki; Fukiyama, Koshiro

    1990-01-01

    We performed exercise thallium-201 myocardial scintigraphy in 32 patients with angina pectoris to study the incidence of perfusion defects, who had no significant organic stenosis on coronary angiography. None of them had myocardial infarction or cardiomyopathy. Thallium-201 myocardial scintigraphy and 12-lead ECG recording were performed during supine bicycle ergometer exercise. Perfusion defects in thallium-201 scintigrams in SPECT images were assessed during visual analysis by two observers. In the coronary angiograms obtained during intravenous infusion of nitroglycerin, the luminal diameter of 75% stenosis or less in the AHA classification was regarded as an insignificant organic stenosis. Myocardial perfusion defects in the thallium-201 scintigrams were detected in eight (25%) of the 32 patients. Six of these eight patients had variant angina documented during spontaneous attacks with ST elevations in standard 12-lead ECGs. Perfusion defects were demonstrated at the inferior or infero-posterior regions in six patients, one of whom had concomitant anteroseptal defect. The defects were not always accompanied by chest pain. All but one patient demonstrating inferior or inferoposterior defects showed ST depression in leads II, III and aV F on their ECGs, corresponding to inferior wall ischemia. The exception was a case with right bundle branch block. Thus, 25% of the patients with angina pectoris, who had no evidence of significant organic stenosis on their coronary angiograms, exhibited exercise-induced perfusion defects in their thallium-201 scintigrams. Coronary spasms might have caused myocardial ischemia in these patients. (author)

  2. Edge dislocations as sinks for sub-nanometric radiation induced defects in α-iron

    Science.gov (United States)

    Anento, N.; Malerba, L.; Serra, A.

    2018-01-01

    The role of edge dislocations as sinks for small radiation induced defects in bcc-Fe is investigated by means of atomistic computer simulation. In this work we investigate by Molecular Statics (T = 0K) the interaction between an immobile dislocation line and defect clusters of small sizes invisible experimentally. The study highlights in particular the anisotropy of the interaction and distinguishes between absorbed and trapped defects. When the considered defect intersects the dislocation glide plane and the distance from the dislocation line to the defect is on the range between 2 nm and 4 nm, either total or partial absorption of the cluster takes place leading to the formation of jogs. Residual defects produced during partial absorption pin the dislocation. By the calculation of stress-strain curves we have assessed the strength of those residues as obstacles for the motion of the dislocation, which is reflected on the unpinning stresses and the binding energies obtained. When the defect is outside this range, but on planes close to the dislocation glide plane, instead of absorption we have observed a capture process. Finally, with a view to introducing explicitly in kinetic Monte Carlo models a sink with the shape of a dislocation line, we have summarized our findings on a table presenting the most relevant parameters, which define the interaction of the dislocation with the defects considered.

  3. High resolution deep level transient spectroscopy and process-induced defects in silicon

    International Nuclear Information System (INIS)

    Evans-Freeman, J.H.; Emiroglu, D.; Vernon-Parry, K.D.

    2004-01-01

    High resolution, or Laplace, deep level transient spectroscopy (LDLTS) enables the identification of very closely spaced energetic levels in a semiconductor bandgap. DLTS may resolve peaks with a separation of tens of electron volts, but LDLTS can resolve defect energy separations as low as a few MeV. In this paper, we present results from LDLTS applied to ion implantation-induced defects in silicon, with particular emphasis on characterisation of end-of-range interstitial type defects. Silicon was implanted with a variety of ions from mass 28 to 166. A combination of LDLTS and direct capture cross-section measurements was employed to show that electrically active small extended defects were present in the as-implanted samples. Larger dislocations were then generated in Si by oxygenation to act as a control sample. These stacking faults had typical lengths of microns, and their electrical activity was subsequently characterised by LDLTS. This was to establish the sensitivity of LDLTS to defects whose carrier capture is characterised by a non-exponential filling process and an evolving band structure as carrier capture proceeds. The LDLTS spectra show several components in capacitance transients originating from both the end-of-range defects, and the stacking faults, and also clearly show that the carrier emission rates reduce as these extended defects fill with carriers. The end-of-range defects and the stacking faults are shown to have the same electrical behaviour

  4. Detection of Defective Sensors in Phased Array Using Compressed Sensing and Hybrid Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Shafqat Ullah Khan

    2016-01-01

    Full Text Available A compressed sensing based array diagnosis technique has been presented. This technique starts from collecting the measurements of the far-field pattern. The system linking the difference between the field measured using the healthy reference array and the field radiated by the array under test is solved using a genetic algorithm (GA, parallel coordinate descent (PCD algorithm, and then a hybridized GA with PCD algorithm. These algorithms are applied for fully and partially defective antenna arrays. The simulation results indicate that the proposed hybrid algorithm outperforms in terms of localization of element failure with a small number of measurements. In the proposed algorithm, the slow and early convergence of GA has been avoided by combining it with PCD algorithm. It has been shown that the hybrid GA-PCD algorithm provides an accurate diagnosis of fully and partially defective sensors as compared to GA or PCD alone. Different simulations have been provided to validate the performance of the designed algorithms in diversified scenarios.

  5. Point defects migration induced by subthreshold focused collisions

    International Nuclear Information System (INIS)

    Tenenbaum, A.; Doan, N.V.

    1976-01-01

    The persistence of the phenomenon of focused atomic collisions in a large range of temperature up to 0.3 Tf in copper have been shown using computer simulation by the Molecular Dynamics Technique. On the other hand, different processes by which the subthreshold collisions can induce a vacancy migration have been investigated. A quantitative model relating the induced vacancy migration to the flux density, direction and energy of incident particles has been developed. For example in an electron irradiation, it is found that the induced vacancy jump frequency depends notably on the incident direction and exhibits a maximum value in the range of electron energy between 60 and 100keV

  6. Genetic Damage Induced by Accidental Environmental Pollutants

    Directory of Open Access Journals (Sweden)

    Beatriz Pérez-Cadahía

    2006-01-01

    Full Text Available Petroleum is one of the main energy sources worldwide. Its transport is performed by big tankers following some established marine routes. In the last 50 years a total amount of 37 oil tankers have given rise to great spills in different parts of the world, Prestige being the last one. After the accident, a big human mobilisation took place in order to clean beaches, rocks and fauna, trying to reduce the environmental consequences of this serious catastrophe. These people were exposed to the complex mixture of compounds contained in the oil. This study aimed at determine the level of environmental exposure to volatile organic compounds (VOC, and the possible damage induced on the population involved in the different cleaning tasks by applying the genotoxicity tests sister chromatid exchanges (SCE, micronucleus (MN test, and comet assay. Four groups of individuals were included: volunteers (V, hired manual workers (MW, hired high-pressure cleaner workers (HPW and controls. The higher VOC levels were associated with V environment, followed by MW and lastly by HPW, probably due to the use of high-pressure cleaners. Oil exposure during the cleaning tasks has caused an increase in the genotoxic damage in individuals, the comet assay being the most sensitive biomarker to detect it. Sex, age and tobacco consumption have shown to influence the level of genetic damage, while the effect of using protective devices was less noticeable than expected, perhaps because the kind used was not the most adequate.

  7. Targeting a genetic defect: cystic fibrosis transmembrane conductance regulator modulators in cystic fibrosis

    Directory of Open Access Journals (Sweden)

    Nico Derichs

    2013-03-01

    Full Text Available Cystic fibrosis (CF is caused by genetic mutations that affect the cystic fibrosis transmembrane conductance regulator (CFTR protein. These mutations can impact the synthesis and transfer of the CFTR protein to the apical membrane of epithelial cells, as well as influencing the gating or conductance of chloride and bicarbonate ions through the channel. CFTR dysfunction results in ionic imbalance of epithelial secretions in several organ systems, such as the pancreas, gastrointestinal tract, liver and the respiratory system. Since discovery of the CFTR gene in 1989, research has focussed on targeting the underlying genetic defect to identify a disease-modifying treatment for CF. Investigated management strategies have included gene therapy and the development of small molecules that target CFTR mutations, known as CFTR modulators. CFTR modulators are typically identified by high-throughput screening assays, followed by preclinical validation using cell culture systems. Recently, one such modulator, the CFTR potentiator ivacaftor, was approved as an oral therapy for CF patients with the G551D-CFTR mutation. The clinical development of ivacaftor not only represents a breakthrough in CF care but also serves as a noteworthy example of personalised medicine.

  8. Radiation-induced defects formation in Bi-containing vitreous chalcogenides

    International Nuclear Information System (INIS)

    Shpotyuk, O.; Vakiv, M.; Balitska, V.; Kovalskiy, A.

    1997-01-01

    Processes of formation and annihilation of coordination defects in As 2 Se 3 Bi y and (As 2 Se 3 )(Bi 2 Se 3 ) y amorphous chalcogenide semiconductors induced by influence of Co 60 gamma-irradiation are investigated by photoelectric spectroscopy method. It is obtained that radiation-induced changes of photoelectrical properties on bioconcentration of As 2 Se 3 Bi y glasses are characterized by anomalous concentration dependence. The nature of this effect is associated with diamagnetic coordination defects formation. (author). 19 refs, 3 figs

  9. Radiation-induced defects formation in Bi-containing vitreous chalcogenides

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O.; Vakiv, M.; Balitska, V.; Kovalskiy, A. [Institute of Materials, Lvov (Ukraine)

    1997-12-01

    Processes of formation and annihilation of coordination defects in As{sub 2}Se{sub 3}Bi{sub y} and (As{sub 2}Se{sub 3})(Bi{sub 2}Se{sub 3}){sub y} amorphous chalcogenide semiconductors induced by influence of Co{sup 60} gamma-irradiation are investigated by photoelectric spectroscopy method. It is obtained that radiation-induced changes of photoelectrical properties on bioconcentration of As{sub 2}Se{sub 3}Bi{sub y} glasses are characterized by anomalous concentration dependence. The nature of this effect is associated with diamagnetic coordination defects formation. (author). 19 refs, 3 figs.

  10. Effects of point defect trapping and solute segregation on irradiation-induced swelling and creep

    International Nuclear Information System (INIS)

    Mansur, L.K.

    1978-01-01

    The theory of irradiation swelling and creep, generalized to include impurity trapping of point defects and impurity-induced changes in sink efficiencies for point defects, is reviewed. The mathematical framework is developed and significant results are described. These include the relation between vacancy and interstitial trapping and the effectiveness of trapping as compared to segregation-induced changes in sink efficiencies in modifying void nucleation, void growth, and creep. Current understanding is critically assessed. Several areas requiring further development are identified. In particular those given special attention are the treatment of nondilute solutions and the consequences of current uncertainties in fundamental materials properties whose importance has been identified using the theory

  11. Universal Effectiveness of Inducing Magnetic Moments in Graphene by Amino-Type sp3-Defects

    Directory of Open Access Journals (Sweden)

    Tao Tang

    2018-04-01

    Full Text Available Inducing magnetic moments in graphene is very important for its potential application in spintronics. Introducing sp3-defects on the graphene basal plane is deemed as the most promising approach to produce magnetic graphene. However, its universal validity has not been very well verified experimentally. By functionalization of approximately pure amino groups on graphene basal plane, a spin-generalization efficiency of ~1 μB/100 NH2 was obtained for the first time, thus providing substantial evidence for the validity of inducing magnetic moments by sp3-defects. As well, amino groups provide another potential sp3-type candidate to prepare magnetic graphene.

  12. Sorafenib-induced defective autophagy promotes cell death by necroptosis.

    Science.gov (United States)

    Kharaziha, Pedram; Chioureas, Dimitris; Baltatzis, George; Fonseca, Pedro; Rodriguez, Patricia; Gogvadze, Vladimir; Lennartsson, Lena; Björklund, Ann-Charlotte; Zhivotovsky, Boris; Grandér, Dan; Egevad, Lars; Nilsson, Sten; Panaretakis, Theocharis

    2015-11-10

    Autophagy is one of the main cytoprotective mechanisms that cancer cells deploy to withstand the cytotoxic stress and survive the lethal damage induced by anti-cancer drugs. However, under specific conditions, autophagy may, directly or indirectly, induce cell death. In our study, treatment of the Atg5-deficient DU145 prostate cancer cells, with the multi-tyrosine kinase inhibitor, sorafenib, induces mitochondrial damage, autophagy and cell death. Molecular inhibition of autophagy by silencing ULK1 and Beclin1 rescues DU145 cells from cell death indicating that, in this setting, autophagy promotes cell death. Re-expression of Atg5 restores the lipidation of LC3 and rescues DU145 and MEF atg5-/- cells from sorafenib-induced cell death. Despite the lack of Atg5 expression and LC3 lipidation, DU145 cells form autophagosomes as demonstrated by transmission and immuno-electron microscopy, and the formation of LC3 positive foci. However, the lack of cellular content in the autophagosomes, the accumulation of long-lived proteins, the presence of GFP-RFP-LC3 positive foci and the accumulated p62 protein levels indicate that these autophagosomes may not be fully functional. DU145 cells treated with sorafenib undergo a caspase-independent cell death that is inhibited by the RIPK1 inhibitor, necrostatin-1. Furthermore, treatment with sorafenib induces the interaction of RIPK1 with p62, as demonstrated by immunoprecipitation and a proximity ligation assay. Silencing of p62 decreases the RIPK1 protein levels and renders necrostatin-1 ineffective in blocking sorafenib-induced cell death. In summary, the formation of Atg5-deficient autophagosomes in response to sorafenib promotes the interaction of p62 with RIPK leading to cell death by necroptosis.

  13. Electric field deformation in diamond sensors induced by radiation defects

    Energy Technology Data Exchange (ETDEWEB)

    Kassel, Florian; Boer, Wim de; Boegelspacher, Felix; Dierlamm, Alexander; Mueller, Thomas; Steck, Pia [Institut fuer Experimentelle Kernphysik (IEKP), Karlsruher Institut fuer Technologie (KIT) (Germany); Dabrowski, Anne; Guthoff, Moritz [CERN (Switzerland)

    2016-07-01

    The BCML system is a beam monitoring device in the CMS experiment at the LHC. As detectors 32 poly-crystalline CVD diamond sensors are positioned in a ring around the beam pipe at a distance of ±1.8 m and ±14.4 m from the interaction point. The radiation hardness of the diamond sensors in terms of measured signal during operation was significantly lower than expected from laboratory measurements. At high particle rates, such as those occurring during the operation of the LHC, a significant fraction of the defects act as traps for charge carriers. This space charge modifies the electrical field in the sensor bulk leading to a reduction of the charge collection efficiency (CCE). A diamond irradiation campaign was started to investigate the rate dependent electrical field deformation with respect to the radiation damage. Besides the electrical field measurements via the Transient Current Technique, the CCE was measured. The experimental results were used to create an effective trap model that takes the radiation damage into account. Using this trap model the rate dependent electrical field deformation and the CCE were simulated with the software ''SILVACO TCAD''. This talk compares the experimental measurement results with the simulations.

  14. Thermal conductivity of graphene with defects induced by electron beam irradiation

    Science.gov (United States)

    Malekpour, Hoda; Ramnani, Pankaj; Srinivasan, Srilok; Balasubramanian, Ganesh; Nika, Denis L.; Mulchandani, Ashok; Lake, Roger K.; Balandin, Alexander A.

    2016-07-01

    We investigate the thermal conductivity of suspended graphene as a function of the density of defects, ND, introduced in a controllable way. High-quality graphene layers are synthesized using chemical vapor deposition, transferred onto a transmission electron microscopy grid, and suspended over ~7.5 μm size square holes. Defects are induced by irradiation of graphene with the low-energy electron beam (20 keV) and quantified by the Raman D-to-G peak intensity ratio. As the defect density changes from 2.0 × 1010 cm-2 to 1.8 × 1011 cm-2 the thermal conductivity decreases from ~(1.8 +/- 0.2) × 103 W mK-1 to ~(4.0 +/- 0.2) × 102 W mK-1 near room temperature. At higher defect densities, the thermal conductivity reveals an intriguing saturation-type behavior at a relatively high value of ~400 W mK-1. The thermal conductivity dependence on the defect density is analyzed using the Boltzmann transport equation and molecular dynamics simulations. The results are important for understanding phonon - point defect scattering in two-dimensional systems and for practical applications of graphene in thermal management.We investigate the thermal conductivity of suspended graphene as a function of the density of defects, ND, introduced in a controllable way. High-quality graphene layers are synthesized using chemical vapor deposition, transferred onto a transmission electron microscopy grid, and suspended over ~7.5 μm size square holes. Defects are induced by irradiation of graphene with the low-energy electron beam (20 keV) and quantified by the Raman D-to-G peak intensity ratio. As the defect density changes from 2.0 × 1010 cm-2 to 1.8 × 1011 cm-2 the thermal conductivity decreases from ~(1.8 +/- 0.2) × 103 W mK-1 to ~(4.0 +/- 0.2) × 102 W mK-1 near room temperature. At higher defect densities, the thermal conductivity reveals an intriguing saturation-type behavior at a relatively high value of ~400 W mK-1. The thermal conductivity dependence on the defect density is

  15. High-dose irradiation induces cell cycle arrest, apoptosis, and developmental defects during Drosophila oogenesis.

    Directory of Open Access Journals (Sweden)

    Hee Jin Shim

    Full Text Available Ionizing radiation (IR treatment induces a DNA damage response, including cell cycle arrest, DNA repair, and apoptosis in metazoan somatic cells. Because little has been reported in germline cells, we performed a temporal analysis of the DNA damage response utilizing Drosophila oogenesis as a model system. Oogenesis in the adult Drosophila female begins with the generation of 16-cell cyst by four mitotic divisions of a cystoblast derived from the germline stem cells. We found that high-dose irradiation induced S and G2 arrests in these mitotically dividing germline cells in a grp/Chk1- and mnk/Chk2-dependent manner. However, the upstream kinase mei-41, Drosophila ATR ortholog, was required for the S-phase checkpoint but not for the G2 arrest. As in somatic cells, mnk/Chk2 and dp53 were required for the major cell death observed in early oogenesis when oocyte selection and meiotic recombination occurs. Similar to the unscheduled DNA double-strand breaks (DSBs generated from defective repair during meiotic recombination, IR-induced DSBs produced developmental defects affecting the spherical morphology of meiotic chromosomes and dorsal-ventral patterning. Moreover, various morphological abnormalities in the ovary were detected after irradiation. Most of the IR-induced defects observed in oogenesis were reversible and were restored between 24 and 96 h after irradiation. These defects in oogenesis severely reduced daily egg production and the hatch rate of the embryos of irradiated female. In summary, irradiated germline cells induced DSBs, cell cycle arrest, apoptosis, and developmental defects resulting in reduction of egg production and defective embryogenesis.

  16. Stereomicroscopic evaluation of dentinal defects induced by new rotary system: "ProTaper NEXT".

    Science.gov (United States)

    Shori, Deepa Deepak; Shenoi, Pratima Ramakrishna; Baig, Arshia R; Kubde, Rajesh; Makade, Chetana; Pandey, Swapnil

    2015-01-01

    The objective of this study was to evaluate dentinal defects formed by new rotary system - Protaper next™ (PTN). Sixty single-rooted premolars were selected. All specimens were decoronated and divided into four groups, each group having 15 specimens. Group I specimens were prepared by Hand K-files (Mani), Group II with ProTaper Universal (PT; Dentsply Maillefer), Group III with Hero Shaper (HS; Micro-Mega, Besancon, France), and Group IV with PTN (Dentsply Maillefer). Roots of each specimen were sectioned at 3, 6, and 9mm from the apex and were then viewed under a stereomicroscope to evaluate presence or absence of dentinal defects. In roots prepared with hand files (HFs) showed lowest percentage of dentinal defects (6.7%); whereas in roots prepared with PT, HS, and PTN it was 40, 66.7, and 26.7%, respectively. There was significant difference between the HS group and the PTN group (P hand instruments induced minimal defects.

  17. Defect-impurity complex induced long-range ferromagnetism in GaN nanowires

    KAUST Repository

    Assa Aravindh, S

    2015-12-14

    Present work investigates the structural, electronic and magnetic properties of Gd doped wurtzite GaN nanowires (NWs) oriented along the [0001] direction in presence of intrinsic defects by employing the GGA + U approximation. We find that Ga vacancy (VGa) exhibits lower formation energy compared to N vacancy. Further stabilization of point defects occurs due to the presence of Gd. The strength of ferromagnetism (FM) increases by additional positive charge induced by the VGa. Electronic structure analysis shows that VGa introduces defect levels in the band gap leading to ferromagnetic coupling due to the hybridization of the p states of the Ga and N atoms with the Gd d and f states. Ferromagnetic exchange coupling energy of 76.4 meV is obtained in presence of Gd-VGa complex; hence, the FM is largely determined by the cation vacancy-rare earth complex defects in GaN NWs.

  18. Defect-impurity complex induced long-range ferromagnetism in GaN nanowires

    KAUST Repository

    Assa Aravindh, S; Roqan, Iman S.

    2015-01-01

    Present work investigates the structural, electronic and magnetic properties of Gd doped wurtzite GaN nanowires (NWs) oriented along the [0001] direction in presence of intrinsic defects by employing the GGA + U approximation. We find that Ga vacancy (VGa) exhibits lower formation energy compared to N vacancy. Further stabilization of point defects occurs due to the presence of Gd. The strength of ferromagnetism (FM) increases by additional positive charge induced by the VGa. Electronic structure analysis shows that VGa introduces defect levels in the band gap leading to ferromagnetic coupling due to the hybridization of the p states of the Ga and N atoms with the Gd d and f states. Ferromagnetic exchange coupling energy of 76.4 meV is obtained in presence of Gd-VGa complex; hence, the FM is largely determined by the cation vacancy-rare earth complex defects in GaN NWs.

  19. Transformation between divacancy defects induced by an energy pulse in graphene.

    Science.gov (United States)

    Xia, Jun; Liu, XiaoYi; Zhou, Wei; Wang, FengChao; Wu, HengAn

    2016-07-08

    The mutual transformations among the four typical divacancy defects induced by a high-energy pulse were studied via molecular dynamics simulation. Our study revealed all six possible mutual transformations and found that defects transformed by absorbing energy to overcome the energy barrier with bonding, debonding, and bond rotations. The reversibility of defect transformations was also investigated by potential energy analysis. The energy difference was found to greatly influence the transformation reversibility. The direct transformation path was irreversible if the energy difference was too large. We also studied the correlation between the transformation probability and the input energy. It was found that the transformation probability had a local maxima at an optimal input energy. The introduction of defects and their structural evolutions are important for tailoring the exceptional properties and thereby performances of graphene-based devices, such as nanoporous membranes for the filtration and desalination of water.

  20. Radiation induced mutants in elite genetic background for the augmentation of genetic diversity

    International Nuclear Information System (INIS)

    Kumar, V.; Bhagwat, S.G.

    2011-01-01

    Rice (Oryza sativa L.), an important food crop for India, shows large genetic diversity. However, despite the large genetic resource, high genetic similarity is reported in cultivated varieties indicating genetic erosion. Radiation induced mutations provide genetic variability in elite background. In the present study, twenty gamma ray induced mutants of rice variety WL112 (carrying sd-1 semi-dwarfing gene) were analysed for genetic diversity using microsatellite markers. The high range of genetic diversity among mutants indicated that the mutants possess potential for enhancing variability in rice. Cluster analysis showed presence of five clusters having small sub-clusters. Earliness, semi-dwarf stature or resistance to blast disease observed among the mutants showed that these will be useful in breeding programmes. (author)

  1. Response of induced bone defects in horses to collagen matrix containing the human parathyroid hormone gene.

    Science.gov (United States)

    Backstrom, Kristin C; Bertone, Alicia L; Wisner, Erik R; Weisbrode, Stephen E

    2004-09-01

    To determine whether human parathyroid hormone (hPTH) gene in collagen matrix could safely promote bone formation in diaphyseal or subchondral bones of horses. 8 clinically normal adult horses. Amount, rate, and quality of bone healing for 13 weeks were determined by use of radiography, quantitative computed tomography, and histomorphometric analysis. Diaphyseal cortex and subchondral bone defects of metacarpi were filled with hPTH(1-34) gene-activated matrix (GAM) or remained untreated. Joints were assessed on the basis of circumference, synovial fluid analysis, pain on flexion, lameness, and gross and histologic examination. Bone volume index was greater for cortical defects treated with hPTH(1-34) GAM, compared with untreated defects. Bone production in cortical defects treated with hPTH(1-34) GAM positively correlated with native bone formation in untreated defects. In contrast, less bone was detected in hPTH(1-34) GAM-treated subchondral bone defects, compared with untreated defects, and histology confirmed poorer healing and residual collagen sponge. Use of hPTH(1-34) GAM induced greater total bone, specifically periosteal bone, after 13 weeks of healing in cortical defects of horses. The hPTH(1-34) GAM impeded healing of subchondral bone but was biocompatible with joint tissues. Promotion of periosteal bone formation may be beneficial for healing of cortical fractures in horses, but the delay in onset of bone formation may negate benefits. The hPTH(1-34) GAM used in this study should not be placed in articular subchondral bone defects, but contact with articular surfaces is unlikely to cause short-term adverse effects.

  2. Reproduction, Smell and Neurodevelopmental disorders: Genetic defects in different hypogonadotropic hypogonadal syndromes.

    Directory of Open Access Journals (Sweden)

    Hernan G VALDES-SOCIN

    2014-07-01

    Full Text Available The neuroendocrine control of reproduction in mammals is governed by a neural hypothalamic network of nearly 1500 gonadotropin-releasing hormone (GnRH secreting neurons that modulate the activity of the reproductive axis across life. Congenital hypogonadotropic hypogonadism (HH is a clinical syndrome that is characterized by partial or complete pubertal failure. HH may result from inadequate hypothalamic GnRH axis activation, or a failure of pituitary gonadotropin secretion/effects. In man, several genes that participate in olfactory and GnRH neuronal migration are thought to interact during the embryonic life. A growing number of mutations in different genes are responsible for congenital HH. Based on the presence or absence of olfaction dysfunction, HH is divided in two syndromes: HH with olfactory alterations (Kallmann syndrome and idiopathic hypogonadotropic hypogonadism (IHH with normal smell (normosmic IHH. Kallmann syndrome (KS is a heterogeneous disorder affecting 1 in 5000 males, with a 3-5 fold of males over females. KS is associated with mutations in KAL1, FGFR1/FGF8, FGF17, IL17RD, PROK2/PROKR2, NELF, CHD7, HS6ST1, FLRT3, SPRY4, DUSP6, SEMA3A, NELF and WDR11 genes that are related to defects in neuronal migration. These reproductive and olfactory deficits include a variable non reproductive phenotype, including sensorineural deafness, coloboma, bimanual synkinesis, craniofacial abnormalities and/or renal agenesis. Interestingly, defects in PROKR2, FGFR1, FGF8, CHD7, DUSP6, and WDR11 genes are also associated with normosmic IHH, whereas mutations in KISS1/KISSR, TAC3/TACR3, GNRH1/GNRHR, LEP/LEPR, HESX1, FSHB and LHB are only present in patients with normosmic IHH. In this paper, we summarize the reproductive, neurodevelopmental and genetic aspects of HH in human pathology.

  3. Circular patterns of calcium oxalate monohydrate induced by defective Langmuir-Blodgett film on quartz substrates

    Energy Technology Data Exchange (ETDEWEB)

    He Jieyu [Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Ouyang Jianming [Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China)], E-mail: toyjm@jnu.edu.cn

    2009-01-01

    The defective Langmuir-Blodgett (LB) film of dipalmitoylphosphatidylcholine (DPPC) on quartz injured by potassium oxalate (K{sub 2}C{sub 2}O{sub 4}) was used as a model system to induce growth of calcium oxalate crystals. Atomic force microscopy (AFM) indicated that circular defective domains with a diameter of 1-200 {mu}m existed in the LB film. Scanning electron microscopy (SEM) showed circular patterns of aggregated calcium oxalate monohydrate (COM) crystallites were induced by these defective domains. It was ascribed to that the interaction between the negatively-charged oxalate ions and the phosphatidyl groups in DPPC headgroups makes the phospholipid molecules rearranged and exist in an out-of-order state in the LB film, especially at the boundaries of liquid-condensed (LC)/liquid-expanded (LE) phases, which provide much more nucleating sites for COM crystals.

  4. Evaluation of common genetic variants in 82 candidate genes as risk factors for neural tube defects

    LENUS (Irish Health Repository)

    Pangilinan, Faith

    2012-08-02

    AbstractBackgroundNeural tube defects (NTDs) are common birth defects (~1 in 1000 pregnancies in the US and Europe) that have complex origins, including environmental and genetic factors. A low level of maternal folate is one well-established risk factor, with maternal periconceptional folic acid supplementation reducing the occurrence of NTD pregnancies by 50-70%. Gene variants in the folate metabolic pathway (e.g., MTHFR rs1801133 (677 C > T) and MTHFD1 rs2236225 (R653Q)) have been found to increase NTD risk. We hypothesized that variants in additional folate\\/B12 pathway genes contribute to NTD risk.MethodsA tagSNP approach was used to screen common variation in 82 candidate genes selected from the folate\\/B12 pathway and NTD mouse models. We initially genotyped polymorphisms in 320 Irish triads (NTD cases and their parents), including 301 cases and 341 Irish controls to perform case–control and family based association tests. Significantly associated polymorphisms were genotyped in a secondary set of 250 families that included 229 cases and 658 controls. The combined results for 1441 SNPs were used in a joint analysis to test for case and maternal effects.ResultsNearly 70 SNPs in 30 genes were found to be associated with NTDs at the p < 0.01 level. The ten strongest association signals (p-value range: 0.0003–0.0023) were found in nine genes (MFTC, CDKN2A, ADA, PEMT, CUBN, GART, DNMT3A, MTHFD1 and T (Brachyury)) and included the known NTD risk factor MTHFD1 R653Q (rs2236225). The single strongest signal was observed in a new candidate, MFTC rs17803441 (OR = 1.61 [1.23-2.08], p = 0.0003 for the minor allele). Though nominally significant, these associations did not remain significant after correction for multiple hypothesis testing.ConclusionsTo our knowledge, with respect to sample size and scope of evaluation of candidate polymorphisms, this is the largest NTD genetic association study reported to date. The scale of the study and the

  5. Evaluation of common genetic variants in 82 candidate genes as risk factors for neural tube defects

    Directory of Open Access Journals (Sweden)

    Pangilinan Faith

    2012-08-01

    Full Text Available Abstract Background Neural tube defects (NTDs are common birth defects (~1 in 1000 pregnancies in the US and Europe that have complex origins, including environmental and genetic factors. A low level of maternal folate is one well-established risk factor, with maternal periconceptional folic acid supplementation reducing the occurrence of NTD pregnancies by 50-70%. Gene variants in the folate metabolic pathway (e.g., MTHFR rs1801133 (677 C > T and MTHFD1 rs2236225 (R653Q have been found to increase NTD risk. We hypothesized that variants in additional folate/B12 pathway genes contribute to NTD risk. Methods A tagSNP approach was used to screen common variation in 82 candidate genes selected from the folate/B12 pathway and NTD mouse models. We initially genotyped polymorphisms in 320 Irish triads (NTD cases and their parents, including 301 cases and 341 Irish controls to perform case–control and family based association tests. Significantly associated polymorphisms were genotyped in a secondary set of 250 families that included 229 cases and 658 controls. The combined results for 1441 SNPs were used in a joint analysis to test for case and maternal effects. Results Nearly 70 SNPs in 30 genes were found to be associated with NTDs at the p MFTC, CDKN2A, ADA, PEMT, CUBN, GART, DNMT3A, MTHFD1 and T (Brachyury and included the known NTD risk factor MTHFD1 R653Q (rs2236225. The single strongest signal was observed in a new candidate, MFTC rs17803441 (OR = 1.61 [1.23-2.08], p = 0.0003 for the minor allele. Though nominally significant, these associations did not remain significant after correction for multiple hypothesis testing. Conclusions To our knowledge, with respect to sample size and scope of evaluation of candidate polymorphisms, this is the largest NTD genetic association study reported to date. The scale of the study and the stringency of correction are likely to have contributed to real associations failing to survive

  6. Coordination defects in vitreous As2S3 induced by γ-irradiation

    International Nuclear Information System (INIS)

    Shpotyuk, O.; Balitska, V.

    1997-01-01

    Destruction-polymerization transformations in vitreous As 2 S 3 , associated with coordination defects formation process induced by γ-irradiation, were studied by the IR Fourier Spectroscopy method in the region of 400-100 cm -1 . All topological variants of these processes, statistically possible in the investigated samples, were taken into account for physical consideration of the real structural changes. (author)

  7. Radionuclide release from PWR spent fuel specimens with induced cladding defects

    International Nuclear Information System (INIS)

    Wilson, C.N.; Oversby, V.M.

    1984-03-01

    Radionuclide releases from pressurized water reactor (PWR) spent fuel rod specimens containing various artificially induced cladding defects were compared by leach testing. The study was conducted in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) Waste Package Task to evaluate the effectiveness of failed cladding as a barrier to radionuclide release. Test description and results are presented

  8. Radionuclide release from PWR spent fuel specimens with induced cladding defects

    International Nuclear Information System (INIS)

    Wilson, C.N.; Oversby, V.M.

    1984-03-01

    Radionuclide releases from pressurized water reactor (PWR) spent fuel rod specimens containing various artificially induced cladding defects were compared by leach testing. The study was conducted in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) Waste Package Task to evaluate the effectiveness of failed cladding as a barrier to radionuclide release. Test description and results are presented. 6 references, 4 figures

  9. Electron paramagnetic resonance study on the ionizing radiation induced defects of the tooth enamel hydroxyapatite

    International Nuclear Information System (INIS)

    Oliveira, Liana Macedo de

    1995-01-01

    Hydroxyapatite is the main constituent of calcified tissues. Defects induced by ionizing radiations in this biomineral can present high stability and then, these are used as biological markers in radiological accidents, irradiated food identifying and geological and archaeological dating. In this work, paramagnetic centers induced on the enamel of the teeth by environmental ionizing radiation, are investigated by electron paramagnetic resonance (EPR). Decay thermal kinetic presents high complexity and shows the formation of different electron ligation energy centers and structures

  10. Radiation-induced defects in chalcogenide glasses characterized by combined optical spectroscopy, XPS and PALS methods

    International Nuclear Information System (INIS)

    Shpotyuk, O.; Kovalskiy, A.; Jain, H.; Golovchak, R.; Zurawska, A.

    2007-01-01

    Temperature-dependent optical absorption spectroscopy, high-resolution X-ray photoelectron spectroscopy and positron annihilation lifetimes spectroscopy are utilized to understand radiation-induced changes in Ge-Sb-S chalcogenide glasses. Theoretically predicted topological scheme of γ-induced coordination defect formation in stoichiometric Ge 23.5 Sb 11.8 S 64.7 glass composition is supported by these measurements. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. In vitro chondrogenesis and in vivo repair of osteochondral defect with human induced pluripotent stem cells.

    Science.gov (United States)

    Ko, Ji-Yun; Kim, Kyung-Il; Park, Siyeon; Im, Gun-Il

    2014-04-01

    The purpose of this study was to investigate the chondrogenic features of human induced pluripotent stem cells (hiPSCs) and examine the differences in the chondrogenesis between hiPSCs and human bone marrow-derived MSCs (hBMMSCs). Embryoid bodies (EBs) were formed from undifferentiated hiPSCs. After EBs were dissociated into single cells, chondrogenic culture was performed in pellets and alginate hydrogel. Chondro-induced hiPSCs were implanted in osteochondral defects created on the patellar groove of immunosuppressed rats and evaluated after 12 weeks. The ESC markers NANOG, SSEA4 and OCT3/4 disappeared while the mesodermal marker BMP-4 appeared in chondro-induced hiPSCs. After 21 days of culture, greater glycosaminoglycan contents and better chondrocytic features including lacuna and abundant matrix formation were observed from chondro-induced hiPSCs compared to chondro-induced hBMMSCs. The expression of chondrogenic markers including SOX-9, type II collagen, and aggrecan in chondro-induced hiPSCs was comparable to or greater than chondro-induced hBMMSCs. A remarkably low level of hypertrophic and osteogenic markers including type X collagen, type I collagen and Runx-2 was noted in chondro-induced hiPSCs compared to chondro-induced hBMMSCs. hiPSCs had significantly greater methylation of several CpG sites in COL10A1 promoter than hBMMSCs in either undifferentiated or chondro-induced state, suggesting an epigenetic cause of the difference in hypertrophy. The defects implanted with chondro-induced hiPSCs showed a significantly better quality of cartilage repair than the control defects, and the majority of cells in the regenerated cartilage consisted of implanted hiPSCs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. In-Situ Photoexcitation-Induced Suppression of Point Defect Generation in Ion Implanted Silicon

    International Nuclear Information System (INIS)

    Cho, C.R.; Rozgonyi, G.A.; Yarykin, N.; Zuhr, R.A.

    1999-01-01

    The formation of vacancy-related defects in n-type silicon has been studied immediately after implantation of He, Si, or Ge ions at 85 K using in-situ DLTS. A-center concentrations in He-implanted samples reach a maximum immediately after implantation, whereas, with Si or Ge ion implanted samples they continuously increase during subsequent anneals. It is proposed that defect clusters, which emit vacancies during anneals, are generated in the collision cascades of Si or Ge ions. An illumination-induced suppression of A-center formation is seen immediately after implantation of He ions at 85 K. This effect is also observed with Si or Ge ions, but only after annealing. The suppression of vacancy complex formation via photoexcitation is believed to occur due to an enhanced recombination of defects during ion implantation, and results in reduced number of vacancies remaining in the defect clusters. In p-type silicon, a reduction in K-center formation and an enhanced migration of defects are concurrently observed in the illuminated sample implanted with Si ions. These observations are consistent with a model where the injection of excess carriers modifies the defect charge state and impacts their diffusion

  13. Polymers under ionizing radiation: the study of energy transfers to radiation induced defects

    International Nuclear Information System (INIS)

    Ventura, A.

    2013-01-01

    Radiation-induced defects created in polymers submitted to ionizing radiations, under inert atmosphere, present the same trend as a function of the dose. When the absorbed dose increases, their concentrations increase then level off. This behavior can be assigned to energy transfers from the polymer to the previously created macromolecular defects; the latter acting as energy sinks. During this thesis, we aimed to specify the influence of a given defect, namely the trans-vinylene, in the behavior of polyethylene under ionizing radiations. For this purpose, we proposed a new methodology based on the specific insertion, at various concentrations, of trans-vinylene groups in the polyethylene backbone through chemical synthesis. This enables to get rid of the variety of created defects on one hand and on the simultaneity of their creation on the other hand. Modified polyethylenes, containing solely trans-vinylene as odd groups, were irradiated under inert atmosphere, using either low LET beams (gamma, beta) or high LET beams (swift heavy ions). During irradiations, both macromolecular defects and H 2 emission were quantified. According to experimental results, among all defects, the influence of the trans-vinylene on the behavior of polyethylene is predominant. (author) [fr

  14. Irradiation induced defects containing oxygen atoms in germanium crystal as studied by deep level transient spectroscopy

    International Nuclear Information System (INIS)

    Fukuoka, Noboru; Kambe, Yoshiyuki; Saito, Haruo; Matsuda, Koji.

    1984-05-01

    Deep level transient spectroscopy was applied to the electron trapping levels which are associated with the irradiation induced lattice defects in germanium crystals. The germanium crystals used in the study were doped with oxygen, antimony or arsenic and the defects were formed by electron irradiation of 1.5MeV or 10MeV. The nature of so called ''thermal defect'' formed by heat treatment at about 670K was also studied. The trapping levels at Esub(c)-0.13eV, Esub(c)-0.25eV and Esub(c)-0.29eV were found to be associated with defects containing oxygen atoms. From the experimental results the Esub(c)-0.25eV level was attributed to the germanium A-center (interstitial oxygen atom-vacancy pair). Another defect associated with the 715cm -1 infrared absorption band was found to have a trapping level at the same position at Esub(c)-0.25eV. The Esub(c)-0.23eV and Esub(c)-0.1eV levels were revealed to be associated with thermal donors formed by heat treatment at about 670K. Additional two peaks (levels) were observed in the DLTS spectrum. The annealing behavior of the levels suggests that the thermal donors originate from not a single type but several types of defects. (author)

  15. Stress-induced evolution and the biosafety of genetically modified

    Indian Academy of Sciences (India)

    This article is focused on the problems of reduction of the risk associated with the deliberate release of genetically modified microorganisms (GMMs) into the environment. Special attention is given to overview the most probable physiological and genetic processes which could be induced in the released GMMs by adverse ...

  16. NDT detection and quantification of induced defects on composite helicopter rotor blade and UAV wing sections

    Science.gov (United States)

    Findeis, Dirk; Gryzagoridis, Jasson; Musonda, Vincent

    2008-09-01

    Digital Shearography and Infrared Thermography (IRT) techniques were employed to test non-destructively samples from aircraft structures of composite material nature. Background information on the techniques is presented and it is noted that much of the inspection work reviewed in the literature has focused on qualitative evaluation of the defects rather than quantitative. There is however, need to quantify the defects if the threshold rejection criterion of whether the component inspected is fit for service has to be established. In this paper an attempt to quantify induced defects on a helicopter main rotor blade and Unmanned Aerospace Vehicle (UAV) composite material is presented. The fringe patterns exhibited by Digital Shearography were used to quantify the defects by relating the number of fringes created to the depth of the defect or flaw. Qualitative evaluation of defects with IRT was achieved through a hot spot temperature indication above the flaw on the surface of the material. The results of the work indicate that the Shearographic technique proved to be more sensitive than the IRT technique. It should be mentioned that there is "no set standard procedure" tailored for testing of composites. Each composite material tested is more likely to respond differently to defect detection and this depends generally on the component geometry and a suitable selection of the loading system to suit a particular test. The experimental procedure that is reported in this paper can be used as a basis for designing a testing or calibration procedure for defects detection on any particular composite material component or structure.

  17. Positron and positronium studies of irradiation-induced defects and microvoids in vitreous metamict silica

    International Nuclear Information System (INIS)

    Hasegawa, M.; Saneyasu, M.; Tabata, M.; Tang, Z.; Nagai, Y.; Chiba, T.; Ito, Y.

    2000-01-01

    To study irradiation-induced defects and structural microvoids in vitreous silica (v-SiO 2 ), positron lifetime, angular correlation of positron annihilation radiation (ACAR), and electron spin resonance (ESR) were measured on v-SiO 2 and quartz (c-SiO 2 ) samples irradiated with fast neutrons up to a dose of 4.1x10 20 n/cm 2 . Two kinds of positron-trapping defects have been found to form in v-SiO 2 by fast neutron irradiation: type-I and type-II defects. Similar defects also appear in the irradiated c-SiO 2 , indicating that both the defects are common in v-SiO 2 and c-SiO 2 . The detailed annealing and photo-illumination studies of positron annihilation and ESR for these two defects suggest that the type-I defects are non-bridging oxygen hole centers (NBOHC), while the type-II defects are oxygen molecules which cannot be detected by ESR. Higher dose irradiation than 1.0x10 20 n/cm 2 causes c-SiO 2 to change to metamict (amorphous) phase (m-SiO 2 ). Positronium (Ps) atoms are found to form in microvoids with an average radius of about 0.3 nm in the v-SiO 2 and m-SiO 2 . This suggests that microvoids proved by Ps are structurally intrinsic open spaces and reflect the topologically disordered structure of these phases in the subnanometer scale

  18. Gibberellin-induced flowering in sexually defective Remusatia vivipara (Araceae

    Directory of Open Access Journals (Sweden)

    Chi-Tung Huang

    2015-03-01

    Full Text Available Remusatia vivipara is an epiphyte of possibly ornamentally and medically important plant, but flowering is rare in fields. The present experiments were conducted to study the influences of different concentrations of gibberellic acid (GA3 and tuber sizes on the flower initiation, inflorescence characteristics and vegetative growth in R. vivipara. GA3 concentration as low as 25 mg L-1 could induce flowering. The results of a binary logistic regression analysis indicated that the flowering was significantly associated both with GA3 concentration and tuber size. However, comparing with the non-GA3 treated tubers, different GA3 concentrations did not significantly affect flowering. The result also showed no significant effect induced by GA3 treatments on the number of days to flower. In contrast, the Wald statistic revealed that both tuber size (2.51–3.00 cm and tuber size (3.01–3.50 cm made more significant contributions to the prediction of flowering. Tuber diameters above 3.01 cm with 100 mg L-1 GA3 treatment could bring all plants to flower. Results of canonical discriminant analysis and ANOVA tests indicated that there were no differences for all inflorescence characters (inflorescence length, male zone length, sterile zone length and female zone length among different concentrations of GA3 tested. On the contrary, significant differences among the tuber diameter classes for all inflorescence characteristics measured were markedly evident. Generally, sizes of almost all inflorescence characteristics increased with increasing tuber sizes. When considering vegetative characters, significant differences in the fresh and dry weights of bulbil stolon were found between treated and untreated tubers. Although there was a trend of increase in weights with increasing GA3 concentrations, but this was not statistically significant. Our results for R. vivipara showed the induction of flowering by GA3 only influence of flower initiation, but no effects

  19. Application of ENDOR-induced electron spin resonance to the study of point defects in solids

    International Nuclear Information System (INIS)

    Niklas, J.R.; Spaeth, J.M.

    1980-01-01

    The technique of ENDOR-induced ESR (EI-ESR) is applied to the investigation of several point defects in insulating crystals. It is shown that the lineshape of the EI-ESR spectrum depends on the ENDOR line used for the experiment. The EI-ESR technique allows the separation of overlapping ESR spectra in the presence of several defects. New applications are the selection of spin states and the determination of relative signs of spin-Hamiltonian parameters, the selection of centre orientations and the assignment of nuclei in complex ENDOR spectra, and the determination of quadrupole interactions which are not resolved in the ENDOR spectrum. (author)

  20. Investigation of defect-induced abnormal body current in fin field-effect-transistors

    International Nuclear Information System (INIS)

    Liu, Kuan-Ju; Tsai, Jyun-Yu; Lu, Ying-Hsin; Liu, Xi-Wen; Chang, Ting-Chang; Chen, Ching-En; Yang, Ren-Ya; Cheng, Osbert; Huang, Cheng-Tung

    2015-01-01

    This letter investigates the mechanism of abnormal body current at the linear region in n-channel high-k/metal gate stack fin field effect transistors. Unlike body current, which is generated by impact ionization at high drain voltages, abnormal body current was found to increase with decreasing drain voltages. Notably, the unusual body leakage only occurs in three-dimensional structure devices. Based on measurements under different operation conditions, the abnormal body current can be attributed to fin surface defect-induced leakage current, and the mechanism is electron tunneling to the fin via the defects, resulting in holes left at the body terminal

  1. Evolution of Radiation Induced Defects in SiC: A Multiscale Simulation Approach

    Science.gov (United States)

    Jiang, Hao

    temperatures beyond that. Even though clusters cannot diffuse by thermal vibrations, we found they can migrate at room temperature under the influence of electron radiation. This is the first direct observation of radiation-induced diffusion of defect clusters in bulk materials. We show that the underlying mechanism of this athermal diffusion is elastic collision between incoming electrons and cluster atoms. Our findings suggest that defect clusters may be mobile under certain irradiation conditions, changing current understanding of cluster annealing process in irradiated SiC. With the knowledge of cluster diffusion in SiC demonstrated in this thesis, we now become able to predict cluster evolution in SiC with good agreement with experimental measurements. This ability can enable us to estimate changes in many properties of irradiated SiC relevant for its applications in reactors. Internal interfaces such as grain boundaries can behave as sinks to radiation induced defects. The ability of GBs to absorb, transport, and annihilate radiation-induced defects (sink strength) is important to understand radiation response of polycrystalline materials and to better design interfaces for improved resistance to radiation damage. Nowadays, it is established GBs' sink strength is not a static property but rather evolves with many factors, including radiation environments, grain size, and GB microstructure. In this thesis, I investigated the response of small-angle tilt and twist GBs to point defects fluxes in SiC. First of all, I found the pipe diffusion of interstitials in tilt GBs is slower than bulk diffusion. This is because the increased interatomic distance at dislocation cores raises the migration barrier of interstitial dumbbells. Furthermore, I show that both the annihilation of interstitials at jogs and jog nucleation from clusters are diffusion-controlled and can occur under off-stoichiometric interstitial fluxes. Finally, a dislocation line model is developed to predict the

  2. Electron-spin-resonance study of radiation-induced paramagnetic defects in oxides grown on (100) silicon substrates

    International Nuclear Information System (INIS)

    Kim, Y.Y.; Lenahan, P.M.

    1988-01-01

    We have used electron-spin resonance to investigate radiation-induced point defects in Si/SiO 2 structures with (100) silicon substrates. We find that the radiation-induced point defects are quite similar to defects generated in Si/SiO 2 structures grown on (111) silicon substrates. In both cases, an oxygen-deficient silicon center, the E' defect, appears to be responsible for trapped positive charge. In both cases trivalent silicon (P/sub b/ centers) defects are primarily responsible for radiation-induced interface states. In earlier electron-spin-resonance studies of unirradiated (100) substrate capacitors two types of P/sub b/ centers were observed; in oxides prepared in three different ways only one of these centers, the P/sub b/ 0 defect, is generated in large numbers by ionizing radiation

  3. Transmission electron microscope study of neutron irradiation-induced defects in silicon

    International Nuclear Information System (INIS)

    Oshima, Ryuichiro; Kawano, Tetsuya; Fujimoto, Ryoji

    1994-01-01

    Commercial Czochralski-grown silicon (Cz-Si) and float-zone silicon (Fz-Si) wafers were irradiated with fission neutrons at various fluences from 10 19 to 10 22 n/cm 2 at temperatures ranging from 473 K to 1043 K. The irradiation induced defect structures were examined by transmission electron microscopy and ultra high voltage electron microscopy, which were compared with Marlowe code computer simulation results. It was concluded that the vacancy-type damage structure formed at 473 K were initiated from collapse of vacancy-rich regions of cascades, while interstitial type defect clusters formed by irradiation above 673 K were associated with interstitial oxygen atoms and free interstitials which diffused out of the cascades. Complex defect structures were identified to consist of {113} and {111} planar faults by the parallel beam illumination diffraction analysis. (author)

  4. Contribution of Metal Defects in the Assembly Induced Emission of Cu Nanoclusters

    KAUST Repository

    Wu, Zhennan

    2017-03-20

    Aggregation/assembly induced emission (AIE) has been observed for metal nanoclusters (NCs), but the origin of the enhanced emission is not fully understood, yet. In this work, the significant contribution of metal defects on AIE is revealed by engineering the self-assembly process of Cu NCs using ethanol. The presence of ethanol leads to a rapid assembly of NCs into ultrathin nanosheets, promoting the formation of metal defects-rich surface. Detailed studies and computer simulation confirm that the metal defects-rich nanosheets possess increased Cu(I)-to-Cu(0) ratio, which greatly influences ligand-to-metal-metal charge transfer and therewith facilitates the radiative relaxation of excitons. Consequently, the Cu NCs self-assembly nanosheets exhibit obvious emission enhancement.

  5. TEM study of radiation induced defects in baffle-former-barrel assembly from decommissioned NPP Greifswald

    International Nuclear Information System (INIS)

    Srba, O.; Michalicka, J.; Keilova, E.; Kocik, K.

    2013-06-01

    A complex transmission electron microscopy (TEM) study of reactor vessel internal (RVI) materials from the baffle-former-barrel assembly from NPP Greifswald (VVER 440), Unit 1 decommissioned after 15 service cycles has been undertaken. All parts of the baffle-former-barrel assembly are made from Ti-stabilized austenitic stainless steel 08Ch18N10T. The materials were exposed to different dose of neutron radiation (2.4 - 11.4 dpa) at temperatures 267 - 398 deg. C depending on position in the core. Three types of radiation induced defects were identified and quantified, namely: dislocations, cavities (voids) and fine-scaled precipitated particles of Ni-Si rich phases. Black-dot type defects were observed too. Operation conditions are around ≅ 300 deg. C that is why we have observed defect typical for both low and high regions of irradiation temperatures. (authors)

  6. [Effect of simvastatin on inducing endothelial progenitor cells homing and promoting bone defect repair].

    Science.gov (United States)

    Song, Quansheng; Wang, Lingying; Zhu, Jinglin; Han, Xiaoguang; Li, Xu; Yang, Yanlin; Sun, Yan; Song, Chunli

    2010-09-01

    To investigate the effect of simvastatin on inducing endothelial progenitor cells (EPCs) homing and promoting bone defect repair, and to explore the mechanism of local implanting simvastatin in promoting bone formation. Simvastatin (50 mg) compounded with polylactic acid (PLA, 200 mg) or only PLA (200 mg) was dissolved in acetone (1 mL) to prepare implanted materials (Simvastatin-PLA material, PLA material). EPCs were harvested from bone marrow of 2 male rabbits and cultured with M199; after identified by immunohistochemistry, the cell suspension of EPCs at the 3rd generation (2 x 10(6) cells/mL) was prepared and transplanted into 12 female rabbits through auricular veins (2 mL). After 3 days, the models of cranial defect with 15 cm diameter were made in the 12 female rabbits. And the defects were repaired with Simvastatin-PLA materials (experimental group, n=6) and PLA materials (control group, n=6), respectively. The bone repair was observed after 8 weeks of operation by gross appearance, X-ray film, and histology; gelatin-ink perfusion and HE staining were used to show the new vessels formation in the defect. Fluorescence in situ hybridization (FISH) was performed to show the EPCs homing at the defect site. All experimental animals of 2 groups survived to the end of the experiment. After 8 weeks in experimental group, new bone formation was observed in the bone defect by gross and histology, and an irregular, hyperdense shadow by X-ray film; no similar changes were observed in control group. FISH showed that the male EPC containing Y chromosome was found in the wall of new vessels in the defect of experimental group, while no male EPC containing Y chromosome was found in control group. The percentage of new bone formation in defect area was 91.63% +/- 4.07% in experimental group and 59.45% +/- 5.43% in control group, showing significant difference (P < 0.05). Simvastatin can promote bone defect repair, and its mechanism is probably associated with inducing EPCs

  7. Behavior of deep level defects on voltage-induced stress of Cu(In,Ga)Se{sub 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.W.; Cho, S.E. [Department of Physics and Semiconductor Science, Dongguk University, Seoul (Korea, Republic of); Jeong, J.H. [Solar Cell Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); Cho, H.Y., E-mail: hycho@dongguk.edu [Department of Physics and Semiconductor Science, Dongguk University, Seoul (Korea, Republic of)

    2015-05-01

    The behavior of deep level defects by a voltage-induced stress for CuInGaSe{sub 2} (CIGS) solar cells has been investigated. CIGS solar cells were used with standard structures which are Al-doped ZnO/i-ZnO/CdS/CIGSe{sub 2}/Mo on soda lime glass, and that resulted in conversion efficiencies as high as 16%. The samples with the same structure were isothermally stressed at 100 °C under the reverse voltages. The voltage-induced stressing in CIGS samples causes a decrease in the carrier density and conversion efficiency. To investigate the behavior of deep level defects in the stressed CIGS cells, photo-induced current transient spectroscopy was utilized, and normally 3 deep level defects (including 2 hole traps and 1 electron trap) were found to be located at 0.18 eV and 0.29 eV above the valence band maximum (and 0.36 eV below the conduction band). In voltage-induced cells, especially, it was found that the decrease of the hole carrier density could be responsible for the increase of the 0.29 eV defect, which is known to be observed in less efficient CIGS solar cells. And the carrier density and the defects are reversible at least to a large extent by resting at room-temperature without the bias voltage. From optical capture kinetics in photo-induced current transient spectroscopy measurement, the types of defects could be distinguished into the isolated point defect and the extended defect. In this work, it is suggested that the increase of the 0.29 eV defect by voltage-induced stress could be due to electrical activation accompanied by a loss of positive ion species and the activated defect gives rise to reduction of the carrier density. - Highlights: • We investigated behavior of deep level defects by voltage-induced stress. • Defect generation could affect the decrease of the conversion efficiency of cells. • Defect generation could be electrically activated by a loss of positive ion species. • Type of defects could be studied with models of point defects

  8. Various categories of defects after surface alloying induced by high current pulsed electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Dian [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Tang, Guangze, E-mail: oaktang@hit.edu.cn [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Xinxin [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Gu, Le [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Sun, Mingren [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-10-01

    Highlights: • Four kinds of defects are found during surface alloying by high current electron beam. • Exploring the mechanism how these defects appear after irradiation. • Increasing pulsing cycles will help to get good surface quality. • Choosing proper energy density will increase surface quality. - Abstract: High current pulsed electron beam (HCPEB) is an attractive advanced materials processing method which could highly increase the mechanical properties and corrosion resistance. However, how to eliminate different kinds of defects during irradiation by HCPEB especially in condition of adding new elements is a challenging task. In the present research, the titanium and TaNb-TiW composite films was deposited on the carburizing steel (SAE9310 steel) by DC magnetron sputtering before irradiation. The process of surface alloying was induced by HCPEB with pulse duration of 2.5 μs and energy density ranging from 3 to 9 J/cm{sup 2}. Investigation of the microstructure indicated that there were several forms of defects after irradiation, such as surface unwetting, surface eruption, micro-cracks and layering. How the defects formed was explained by the results of electron microscopy and energy dispersive spectroscopy. The results also revealed that proper energy density (∼6 J/cm{sup 2}) and multi-number of irradiation (≥50 times) contributed to high quality of alloyed layers after irradiation.

  9. A molecular dynamics simulation study of irradiation induced defects in gold nanowire

    Science.gov (United States)

    Liu, Wenqiang; Chen, Piheng; Qiu, Ruizhi; Khan, Maaz; Liu, Jie; Hou, Mingdong; Duan, Jinglai

    2017-08-01

    Displacement cascade in gold nanowires was studied using molecular dynamics computer simulations. Primary knock-on atoms (PKAs) with different kinetic energies were initiated either at the surface or at the center of the nanowires. We found three kinds of defects that were induced by the cascade, including point defects, stacking faults and crater at the surface. The starting points of PKAs influence the number of residual point defects, and this consequently affect the boundary of anti-radiation window which was proposed by calculation of diffusion of point defects to the free surface of nanowires. Formation of stacking faults that expanded the whole cross-section of gold nanowires was observed when the PKA's kinetic energy was higher than 5 keV. Increasing the PKA's kinetic energy up to more than 10 keV may lead to the formation of crater at the surface of nanowires due to microexplosion of hot atoms. At this energy, PKAs started from the center of nanowires can also result in the creation of crater because length of cascade region is comparable to diameter of nanowires. Both the two factors, namely initial positions of PKAs as well as the craters induced by higher energy irradiation, would influence the ability of radiation resistance of metal nanowires.

  10. Low-dose ionizing radiation alleviates Aβ42-induced defective phenotypes in Drosophila Alzheimer's disease models

    International Nuclear Information System (INIS)

    Hwang, SooJin; Jeong, Hae Min; Nam, Seon Young

    2017-01-01

    Alzheimer's disease (AD) is the most common neurodegenerative disease that is characterized by amyloid plaques, progressive neuronal loss, and gradual deterioration of memory. Amyloid imaging using positron emission tomography (PET) radiotracers have been developed and approved for clinical use in the evaluation of suspected neurodegenerative disease, including AD. Particularly, previous studies involving low-dose ionizing radiation on Aβ 42-treated mouse hippocampal neurons have suggested a potential role for low-dose ionizing radiation in the treatment of AD. However, associated in vivo studies involving the therapy effects of low-dose ionizing radiation on AD are still insufficient. As a powerful cell biological system, Drosophila AD models have been generated and established a useful model organism for study on the etiology of human AD. In this study, we investigated the hormesis effects of low-dose ionizing radiation on Drosophila AD models. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation.

  11. Formation and properties of radiation-induced defects and radiolysis products in lithium orthosilicate

    Energy Technology Data Exchange (ETDEWEB)

    Tiliks, J.E.; Kizane, G.K.; Supe, A.A.; Abramenkovs, A.A.; Tiliks, J.J. (Latvian Univ., Riga (Latvia)); Vasiljev, V.G. (Acad. A.A. Bochvar Inst. of Inorganic Materials, Moscow (USSR))

    1991-12-01

    Formation and properties of radiation-induced defects and radiolysis products in polycrystalline powders and ceramic pellets of Li{sub 4}SiO{sub 4} were studied under the effect of various types of ionizing irradiation ({gamma} quants, accelerated electrons, reactor irradiation), humidity, temperature, impurities in the samples, etc. The content of radiation defects and radiolysis products poorly depends on irradiation type, dose rate, admixture elements. The concentration of defects highly depends on the temperature of irradiation, humidity, granural size. Empirical dependence of radiolysis degree {alpha} on the dose was found: {alpha}=5x10{sup -2}xD{sup 0.5} for {gamma} and electron irradiation (T{sub rad}=300-350 K) and {alpha}=5x10{sup -3}xD{sup 0.5} for reactor radiation (T{sub rad}=700-800 K); {alpha} - matrix dissociation degree (in %); D - dose (in MGy). Colloidal lithium and silicon, lithium and silicon oxides, and O{sub 2} are the final products of radiolysis. Radiation-induced defects change tritium thermo-extraction parameters, deteriorate mechanical, thermo-physical and electric properties of ceramics. (orig.).

  12. A polarity-induced defect mechanism for conductivity and magnetism at polar-nonpolar oxide interfaces.

    Science.gov (United States)

    Yu, Liping; Zunger, Alex

    2014-10-13

    The discovery of conductivity and magnetism at the polar-nonpolar interfaces of insulating nonmagnetic oxides such as LaAlO3 and SrTiO3 has raised prospects for attaining interfacial functionalities absent in the component materials. Yet, the microscopic origin of such emergent phenomena remains unclear, posing obstacles to design of improved functionalities. Here we present first principles calculations of electronic and defect properties of LaAlO3/SrTiO3 interfaces and reveal a unifying mechanism for the origins of both conductivity and magnetism. We demonstrate that the polar discontinuity across the interface triggers thermodynamically the spontaneous formation of certain defects that in turn cancel the polar field induced by the polar discontinuity. The ionization of the spontaneously formed surface oxygen vacancy defects leads to interface conductivity, whereas the unionized Ti-on-Al antisite defects lead to interface magnetism. The proposed mechanism suggests practical design principles for inducing and controlling both conductivity and magnetism at general polar-nonpolar interfaces.

  13. Recombination of charge carriers on radiation-induced defects in silicon doped by transition metals impurities

    CERN Document Server

    Kazakevich, L A

    2003-01-01

    It has been studied the peculiarities of recombination of nonequilibrium charge carriers on radiation-induced defects in received according to Czochralski method p-silicon (p approx 3 - 20 Ohm centre dot cm), doped by one of the impurities of transition metals of the IV-th group of periodic table (titanium, zirconium, hafnium). Experimental results are obtained out of the analysis of temperature and injection dependence of the life time of charge carriers. The results are explained taking into consideration the influences of elastic stress fields created by the aggregates of transition metals atoms on space distribution over the crystal of oxygen and carbon background impurities as well as on the migration of movable radiation-induced defects during irradiation. (authors).

  14. Structural and defects induced phenomena in γ-rays irradiated 6H-SiC

    International Nuclear Information System (INIS)

    Sibuyi, P.; Ngom, B.D.; Kotsedi, L.

    2016-01-01

    Damages and/or defects induced by γ-rays irradiation on 6H-SiC single crystals in channeled configuration towards 〈006〉/〈0012〉 crystallographic directions are reported in the range of 0–1200 kGy. Atomic force microscopy, X-rays diffraction, Raman and photoluminescence investigations were used to obtain a comprehensive set of informations on the nature and population distribution of the induced defects. Primarily, there was no carbon clusterization upon γ-rays irradiation and hence no formation of others SiC polytypes. In contrast, the γ-rays irradiation has induced an increase of the surface roughness at higher doses, which indicates a structural degradation. Larger doses induced an emergence of deeper shallow traps at energies greater than 350 meV below the bandgap. - Highlights: • No formation of others SiC polytypes. • The gamma rays irradiation has induced a slight surface amorphization. • A re-crystallization at lower and higher doses is noticed. • Larger doses induced a substantial internal stress.

  15. 100 MeV silver ions induced defects and modifications in silica glass

    Energy Technology Data Exchange (ETDEWEB)

    Jadhav, Vijay S.; Deore, Avinash V.; Dahiwale, S.S. [Department of Physics, University of Pune, Pune 411007 (India); Kanjilal, D. [Inter University Accelerator Centre, New Delhi 110067 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411007 (India)

    2014-07-15

    Highlights: •Study of silver ion induced defects and modifications in silica glass. •Variation in oxygen deficiency centres (ODA-II) and nonbridging oxygen hole centres (NBOHC). •Study of structural damage in terms of Urbach energy. -- Abstract: A few silica glass samples having 1 cm{sup 2} area and 0.1 cm thickness were irradiated with 100 MeV energy Ag{sup 7+} ions for the fluences ranging from 1 × 10{sup 12} ions/cm{sup 2} to 5 × 10{sup 13} ions/cm{sup 2}. The optical properties and the corresponding induced defects were characterised by the techniques such as UV–Visible, Photoluminescence (PL), Fourier transform infrared (FTIR), and Electron spin resonance (ESR) spectroscopy. The UV–Visible absorption spectra show two peaks, one at 5 eV and another weak peak at 5.8 eV. A peak observed at 5.0 eV corresponds to B{sub 2} band (oxygen deficiency in SiO{sub 2} network) and the peak at 5.8 eV is due to the paramagnetic defects like E′ centre. The intensities of these peaks found to be increased with increase in ion fluence. It attributes to the increase in the concentration of E′ centres and B{sub 2} band respectively. In addition, the optical band gap energy, Urbach energy and the defects concentration have been calculated using Urbach plot. The optical band gap found to be decreased from 4.65 eV to 4.39 eV and the Urbach energy found to be increased from 60 meV to 162 meV. The defect concentration of nonbridging oxygen hole centres (NBOHC) and E′ centres are found to be increased to 1.69 × 10{sup 13} cm{sup −3} and 3.134 × 10{sup 14} cm{sup −3} respectively. In PL spectra, the peak appeared at 1.92 eV and 2.7 eV envisage the defects of nonbridging oxygen hole centres and B{sub 2α} oxygen deficient centres respectively. ESR spectra also confirms the existence of E′ and NBOHC centres. FTIR spectra shows scissioning of Si-O-Si bonds and the formation of Si-H and Si-OH bonds, which supports to the co-existence of the defects induced by Ag

  16. Characterization of radiation-induced defects in ZnO probed by positron annihilation spectroscopy

    International Nuclear Information System (INIS)

    Brunner, S.; Puff, W.; Balogh, A.G.; Mascher, P.

    2001-01-01

    In this study we discuss the microstructural changes after electron and proton irradiation and the thermal evolution of the radiation induced defects during isochronal annealing of single crystals irradiated either with 3 MeV protons or with 1 or 2 MeV electrons, respectively. The investigations were performed with positron lifetime and Doppler-broadening measurements. The differently grown ZnO single crystals show positron bulk lifetimes in the range of 159-173 ps. (orig.)

  17. Defect production and subsequent effects induced by electronic energy loss of swift heavy ion

    International Nuclear Information System (INIS)

    Hou Mingdong; Liu Jie; Sun Youmei; Yin Jingmin; Yao Huijun; Duan Jinglai; Mo Dan; Zhang Ling; Chen Yanfeng; Chinese Academy of Sciences, Beijing

    2008-01-01

    Swift heavy ion in matter is one of forfront fields of nuclear physics in the world. A series of new phenomena were discovered in recent years. The history and sta- tus on the development of this field were reviewed. Electronic energy loss effects induced by swift heavy ion irradiation, such as defect production and evolution, ion latent track formation, phase transformation and anisotropy plastic deformation were introduced emphatically. A trend of future investigation was explored. (authors)

  18. Characterization of radiation-induced defects in ZnO probed by positron annihilation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Brunner, S.; Puff, W. [Technische Univ. Graz (Austria). Inst. fuer Technische Physik; Balogh, A.G. [Technische Hochschule Darmstadt (Germany). FB Materialwissenschaft; Mascher, P. [McMaster Univ., Hamilton, ON (Canada). Dept. of Engineering Physics

    2001-07-01

    In this study we discuss the microstructural changes after electron and proton irradiation and the thermal evolution of the radiation induced defects during isochronal annealing of single crystals irradiated either with 3 MeV protons or with 1 or 2 MeV electrons, respectively. The investigations were performed with positron lifetime and Doppler-broadening measurements. The differently grown ZnO single crystals show positron bulk lifetimes in the range of 159-173 ps. (orig.)

  19. Genetic improvement of soybean through induced mutagenesis

    International Nuclear Information System (INIS)

    Manjaya, J.G.; Nandanwar, R.S.; Thengane, R.J.; Muthiah, A.R.

    2009-01-01

    Soybean (Glycine max (L.) Merril) is one of the important oilseed crops of India. The country produces more than 9.00 million tonnes of soybean per annum and has acquired first place amongst oilseed crops grown in India. Narrow genetic base of cultivated varieties in soybean is of global concern. Efficient mutant production systems, through physical or chemical mutagenesis, have been well established in soybean. A vast amount of genetic variability, of both quantitative and qualitative traits, has been generated through experimental mutagenesis. Two soybean varieties TAMS-38 and TAMS 98-21 have been developed and released for commercial cultivation by Bhabha Atomic Research Centre (BARC). In this paper the role of mutation breeding in soybean improvement has been discussed. (author)

  20. Optical manipulation of photonic defect-modes in cholesteric liquid crystals induced by direct laser-lithography

    International Nuclear Information System (INIS)

    Yoshida, Hiroyuki; Lee, Chee Heng; Miura, Yusuke; Fujii, Akihiko; Ozaki, Masanori

    2008-01-01

    Manipulation of photonic defect-modes in cholesteric liquid crystals (ChLCs), which are one-dimensional pseudo photonic band-gap materials have been demonstrated by an external optical field. A structural defect in which the pitch length of the ChLC in the bulk and the defect are different was introduced by inducing local polymerization in a photo-polymerizable ChLC material by a direct laser-lithography process, and infiltrating a different ChLC material as the defect medium. When an azobenzene dye-doped ChLC was infiltrated in the defect, the trans-cis isomerization of the dye upon ultraviolet (UV) exposure caused the pitch to shorten, changing the contrast in the pitch lengths at the bulk and the defect, leading to a consequent shifting of the defect-mode. The all-optical manipulation was reversible and had high reproducibility

  1. Evaluation of induced color changes in chicken breast meat during simulation of pink color defect.

    Science.gov (United States)

    Holownia, K; Chinnan, M S; Reynolds, A E; Koehler, P E

    2003-06-01

    The objective of the study was to establish a pink threshold and simulate the pink defect in cooked chicken breast meat with treatment combinations that would induce significant changes in the color of raw and cooked meat. The subjective pink threshold used in judging pink discoloration was established at a* = 3.8. Samples of three color groups (normal, lighter than normal, and darker than normal) of boneless, skinless chicken breast muscles were selected based on instrumental color values. The in situ changes were induced using sodium chloride, sodium tripolyphosphate, sodium erythorbate, and sodium nitrite at two levels: present and not present. Fillets in all treatments were subjected to individual injections, followed by tumbling, cooking, and chilling. Samples were analyzed for color [lightness (L*), red/green axis (a*), yellow/blue axis (b*)] and reflectance spectra. Simulation of the pink defect was achieved in eight of the 16 treatment combinations when sodium nitrite was present and in an additional two treatment combinations when it was absent. Pinking in cooked samples was affected (P meat color. Results confirmed that it was possible to simulate the undesired pinking in cooked chicken white meat when in situ conditions were induced by sodium chloride, sodium tripolyphosphate, and sodium nitrite. The continuation of the simulation study can aid in developing alternative processing methods to eliminate potential pink defects.

  2. Surface-defect induced modifications in the optical properties of α-MnO_2 nanorods

    International Nuclear Information System (INIS)

    John, Reenu Elizabeth; Chandran, Anoop; Thomas, Marykutty; Jose, Joshy; George, K.C.

    2016-01-01

    Graphical abstract: - Highlights: • Alpha-MnO_2 nanorods are prepared by chemical method. • Difference in surface defect density is achieved. • Characterized using XRD, Rietveld, XPS, EDS, HR-TEM, BET, UV–vis absorption spectroscopy and PL spectroscopy. • Explains the bandstructure modification due to Jahn–Teller distortions using crystal field theory. • Modification in the intensity of optical emissions related to defect levels validates the concept of surface defect induced tuning of optical properties. - Abstract: The science of defect engineering via surface tuning opens a new route to modify the inherent properties of nanomaterials for advanced functional and practical applications. In this work, two independent synthesis methods (hydrothermal and co-precipitation) are adopted to fabricate α-MnO_2 nanorods with different defect structures so as to understand the effect of surface modifications on their optical properties. The crystal structure and morphology of samples are investigated with the aid of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Atomic composition calculated from energy dispersive spectroscopy (EDS) confirms non-stoichiometry of the samples. The surface properties and chemical environment are thoroughly studied using X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) analysis. Bond angle variance and bond valence sum are determined to validate distortions in the basic MnO_6 octahedron. The surface studies indicate that the concentration of Jahn–Teller manganese (III) (Mn"3"+) ion in the samples differ from each other which results in their distinct properties. Band structure modifications due to Jahn–Teller distortion are examined with the aid of ultraviolet–visible (UV) reflectance and photoluminescence (PL) studies. The dual peaks obtained in derivative spectrum conflict the current concept on the bandgap energy of MnO_2. These studies suggest that

  3. Study of grown-in and radiation-induced defects in indium phosphide

    International Nuclear Information System (INIS)

    Shaban, E.H.

    1986-01-01

    This research is focused on (1) conducting detailed theoretical and experimental study of grown-in and radiation-induced defects in liquid encapsulated Czohralski (LEC) grown, Zn-doped P-type indium phosphide (InP), (2) identifying the physical origin of the defects detected using Deep Level Transient Spectroscopy (DLTS) method, and (3) and developing a second-order model to interpret the presence of nonexponential capacitance transients in DLTS method. Analysis of grown-in and radiation-induced defects in P-type InP is undertaken. The main research results are summarized as follows: (1) DLTS analysis of grown-in defects in liquid LEC-grown, Zn-doped, P-type InP is made in this study. A single-hole trap of E/sub v/ + 0.52 eV is detected with a trap density of 1.8 x 10 15 cm -3 . The physical origin of this hole trap is attributed to a phosphorus vacancy or phosphorus interstitial-related defect. (2) One-MeV electron-irradiated P-type InP introduced two new hole traps, namely E/sub v/ + 0.34 and E/sub v/ + 0.58 eV with introduction rates (dN/sub T/d phi) of 0.4 and 1.2 per electron-cm, respectively. (3) A theoretical model is developed to interpret nonexponential capacitance transients in a deep-level transient spectroscopy method when the capture process competes with the dominant thermal-emission process

  4. Radiation-induced defects in chalcogenide glasses characterized by combined optical spectroscopy, XPS and PALS methods

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Institute of Physics of Jan Dlugosz University, 13/15 al. Armii Krajowej, Czestochowa 42201 (Poland); Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Lviv Institute of Materials of SRC ' ' Carat' ' , 202, Stryjska str., 79031 Lviv (Ukraine); Kovalskiy, A.; Jain, H. [Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Golovchak, R. [Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Lviv Institute of Materials of SRC ' ' Carat' ' , 202, Stryjska str., 79031 Lviv (Ukraine); Zurawska, A. [Opole University of Technology, 75, Ozimska str., Opole 45370 (Poland)

    2007-03-15

    Temperature-dependent optical absorption spectroscopy, high-resolution X-ray photoelectron spectroscopy and positron annihilation lifetimes spectroscopy are utilized to understand radiation-induced changes in Ge-Sb-S chalcogenide glasses. Theoretically predicted topological scheme of {gamma}-induced coordination defect formation in stoichiometric Ge{sub 23.5}Sb{sub 11.8}S{sub 64.7} glass composition is supported by these measurements. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Adaptive repair induced by small doses of γ radiation in repair-defective human cells

    International Nuclear Information System (INIS)

    Zasukhina, G.D.; L'vova, G.N.; Vasil'eva, I.M.; Sinel'shchikova, T.A.; Semyachkina, A.N.

    1993-01-01

    Adaptive repair induced by small doses of gamma radiation was studied in repair-defective xeroderma pigmentosum, gout, and homocystinuria cells. The adaptation of cells induced by small doses of radiation was estimated after subsequent exposure to gamma radiation, 4-nitroquinoline-1-oxide, and N-methyl-N-nitro-N-nitrosoguanidine by three methods: (1) by the reduction in DNA breaks; (2) by induction of resistant DNA synthesis; and (3) by increased reactivation of vaccinia virus. The three cell types in response to the three different mutagens revealed differences in the mechanism of cell defense in excision repair, in the adaptive response, and in Weigl reactivation

  6. On the influence of extrinsic point defects on irradiation-induced point-defect distributions in silicon

    International Nuclear Information System (INIS)

    Vanhellemont, J.; Romano-Rodriguez, A.

    1994-01-01

    A semi-quantitative model describing the influence of interfaces and stress fields on {113}-defect generation in silicon during 1-MeV electron irradiation, is further developed to take into account also the role of extrinsic point defects. It is shown that the observed distribution of {113}-defects in high-flux electron-irradiated silicon and its dependence on irradiation temperature and dopant concentration can be understood by taking into account not only the influence of the surfaces and interfaces as sinks for intrinsic point defects but also the thermal stability of the bulk sinks for intrinsic point defects. In heavily doped silicon the bulk sinks are related with pairing reactions of the dopant atoms with the generated intrinsic point defects or related with enhanced recombination of vacancies and self-interstitials at extrinsic point defects. The obtained theoretical results are correlated with published experimental data on boron-and phosphorus-doped silicon and are illustrated with observations obtained by irradiating cross-section transmission electron microscopy samples of wafer with highly doped surface layers. (orig.)

  7. Stereomicroscopic evaluation of dentinal defects induced by new rotary system: “ProTaper NEXT”

    Science.gov (United States)

    Shori, Deepa Deepak; Shenoi, Pratima Ramakrishna; Baig, Arshia R; Kubde, Rajesh; Makade, Chetana; Pandey, Swapnil

    2015-01-01

    Introduction: The objective of this study was to evaluate dentinal defects formed by new rotary system — Protaper next™ (PTN). Materials and Methods: Sixty single-rooted premolars were selected. All specimens were decoronated and divided into four groups, each group having 15 specimens. Group I specimens were prepared by Hand K-files (Mani), Group II with ProTaper Universal (PT; Dentsply Maillefer), Group III with Hero Shaper (HS; Micro-Mega, Besancon, France), and Group IV with PTN (Dentsply Maillefer). Roots of each specimen were sectioned at 3, 6, and 9mm from the apex and were then viewed under a stereomicroscope to evaluate presence or absence of dentinal defects. Results: In roots prepared with hand files (HFs) showed lowest percentage of dentinal defects (6.7%); whereas in roots prepared with PT, HS, and PTN it was 40, 66.7, and 26.7%, respectively. There was significant difference between the HS group and the PTN group (P hand instruments induced minimal defects. PMID:26069406

  8. A System for Measuring Defect Induced Beam Modulation on Inertial Confinement Fusion-class Laser Optics

    International Nuclear Information System (INIS)

    Runkel, M; Hawley-Fedder, R; Widmayer, C; Williams, W; Weinzapfel, C; Roberts, D

    2005-01-01

    A multi-wavelength laser based system has been constructed to measure defect induced beam modulation (diffraction) from ICF class laser optics. The Nd:YLF-based modulation measurement system (MMS) uses simple beam collimation and imaging to capture diffraction patterns from optical defects onto an 8-bit digital camera at 1053, 527 and 351 nm. The imaging system has a field of view of 4.5 x 2.8 mm 2 and is capable of imaging any plane from 0 to 30 cm downstream from the defect. The system is calibrated using a 477 micron chromium dot on glass for which the downstream diffraction patterns were calculated numerically. Under nominal conditions the system can measure maximum peak modulations of approximately 7:1. An image division algorithm is used to calculate the peak modulation from the diffracted and empty field images after the baseline residual light background is subtracted from both. The peak modulation can then be plotted versus downstream position. The system includes a stage capable of holding optics up to 50 pounds with x and y translation of 40 cm and has been used to measure beam modulation due to solgel coating defects, surface digs on KDP crystals, lenslets in bulk fused silica and laser damage sites mitigated with CO 2 lasers

  9. A System for Measuring Defect Induced Beam Modulation on Inertial Confinement Fusion-class Laser Optics

    Energy Technology Data Exchange (ETDEWEB)

    Runkel, M; Hawley-Fedder, R; Widmayer, C; Williams, W; Weinzapfel, C; Roberts, D

    2005-10-18

    A multi-wavelength laser based system has been constructed to measure defect induced beam modulation (diffraction) from ICF class laser optics. The Nd:YLF-based modulation measurement system (MMS) uses simple beam collimation and imaging to capture diffraction patterns from optical defects onto an 8-bit digital camera at 1053, 527 and 351 nm. The imaging system has a field of view of 4.5 x 2.8 mm{sup 2} and is capable of imaging any plane from 0 to 30 cm downstream from the defect. The system is calibrated using a 477 micron chromium dot on glass for which the downstream diffraction patterns were calculated numerically. Under nominal conditions the system can measure maximum peak modulations of approximately 7:1. An image division algorithm is used to calculate the peak modulation from the diffracted and empty field images after the baseline residual light background is subtracted from both. The peak modulation can then be plotted versus downstream position. The system includes a stage capable of holding optics up to 50 pounds with x and y translation of 40 cm and has been used to measure beam modulation due to solgel coating defects, surface digs on KDP crystals, lenslets in bulk fused silica and laser damage sites mitigated with CO{sub 2} lasers.

  10. Bremsstrahlung-induced highly penetrating probes for nondestructive assay and defect analysis

    CERN Document Server

    Selim, F A; Harmon, J F; Kwofie, J; Spaulding, R; Erickson, G; Roney, T

    2002-01-01

    Nondestructive assay and defect analysis probes based on bremsstrahlung-induced processes have been developed to identify elements and probe defects in large volume samples. Bremsstrahlung beams from (electron accelerators) with end-point energies both above and below neutron emission threshold have been used. Below neutron emission threshold these beams (from 6 MeV small pulsed linacs), which exhibit high penetration, create positrons via pair production inside the material and produce X-ray fluorescence (XRF) radiation. Chemical assays of heavy elements in thick samples up to 10 g/cm sup 2 thick are provided by energy dispersive XRF measurements. The pair-produced positrons annihilate within the material, thereby emitting 511 keV gamma radiation. Doppler broadening spectroscopy of the 511 keV radiation can be performed to characterize the material and measure defects in samples of any desired thickness. This technique has successfully measured induced strain due to tensile stress in steel samples of 0.64 cm...

  11. A review of genome-wide approaches to study the genetic basis for spermatogenic defects.

    Science.gov (United States)

    Aston, Kenneth I; Conrad, Donald F

    2013-01-01

    Rapidly advancing tools for genetic analysis on a genome-wide scale have been instrumental in identifying the genetic bases for many complex diseases. About half of male infertility cases are of unknown etiology in spite of tremendous efforts to characterize the genetic basis for the disorder. Advancing our understanding of the genetic basis for male infertility will require the application of established and emerging genomic tools. This chapter introduces many of the tools available for genetic studies on a genome-wide scale along with principles of study design and data analysis.

  12. Irradiation-induced defects in ZnO studied by positron annihilation spectroscopy

    International Nuclear Information System (INIS)

    Tuomisto, F.; Saarinen, K.; Look, D.C.

    2004-01-01

    We have used positron annihilation spectroscopy to study the point defects induced by 2 MeV electron irradiation (fluence 6 x 10 17 cm -2 ) in single crystal n-type ZnO samples. The positron lifetime measurements have shown that the zinc vacancies in their doubly negative charge state, which act as dominant compensating centers in the as-grown material, are produced in the irradiation and their contribution to the electrical compensation is important. The lifetime measurements reveal also the presence of competing positron traps with low binding energy and lifetime close to that of the bulk lattice. The analysis of the Doppler broadening of the 511 keV annihilation line indicates that these defects can be identified as neutral oxygen vacancies. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Confocal fluorescence microscopy investigation of visible emitting defects induced by electron beam lithography in LIF films

    International Nuclear Information System (INIS)

    Montereali, R. M.; Bigotta, S.; Pace, A.; Piccinini, M.; Burattini, E.; Grilli, A.; Raco, A.; Giammatteo, M.; L'Aquila Univ., L'Aquila; Picozzi, P.; Santucci, S.; L'Aquila Univ., L'Aquila

    2000-01-01

    Low energy electron irradiation of lithium fluoride (LiF), in the form of bulk crystals and films, gives rise to the stable formation of primary F defects and aggregated color centers in a thin layer located at the surface of the investigated material. For the first time a confocal light scanning microscope (CLSM) in fluorescence mode was used to reconstruct the depth distribution of efficiently emitting laser active color centers in a stripe-like region induced by 12 and 16 keV electrons on LiF films thermally evaporated on glass. The formation of the F3+ and F2 aggregated defects appears restricted to the electron penetration and proportional to their energy depth profile, as obtained from Monte Carlo simulations [it

  14. Effect of thermal-convection-induced defects on the performance of perovskite solar cells

    Science.gov (United States)

    Ye, Fei; Xie, Fengxian; Yin, Maoshu; He, Jinjin; Wang, Yanbo; Tang, Wentao; Chen, Han; Yang, Xudong; Han, Liyuan

    2017-07-01

    Thermal-convection-induced defects can cause huge loss in the power conversion efficiency of solution-processed perovskite solar cells. We investigated two types of convection in perovskite solution during the formation of perovskite films. By balancing the convection via special configurations of surface tension and boiling point in mixed γ-butyrolactone (GBL) and dimethylsulfoxide (DMSO), we removed microscopic defects such as rings, bumps, and crevices. The deposited perovskite films were smooth and dense, which enabled a high power conversion efficiency of 17.7% in a 1 cm2 cell area. We believe that the present strategy for controlling the convection can be helpful in improving the perovskite film quality for solvent-rich scalable solution processes of solar cells such as doctor blading, soft-cover deposition, printing, and slot-die coating.

  15. Channeling study of laser-induced defect generation in InP and InAs

    International Nuclear Information System (INIS)

    Burdel', K.K.; Kashkarov, P.K.; Timoshenko, V.Yu.; Chechenin, N.G.

    1992-01-01

    Damage production in InP and InAs single crystals induced by a ruby-laser pulse irradiation with τ p =20 ms in the energy density region W=0.05-1.0 J/cm 2 is studied by the channeling and Rutherford backscattering techniques. The defect generation threshold was determined to be equal to 0.2 J/cm 2 and 0.55 J/cm 2 for InP and InAs crystals, respectively. Stoichiometric defects in InP crystals were observed at W>=0.5 J/cm 2 . The temperature fields in InP and InAs under laser irradiation were calculated. The experimental observations are considered as a result of a selective evaporation of the components from the melt

  16. Irradiation-induced defects in ZnO studied by positron annihilation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tuomisto, F.; Saarinen, K. [Laboratory of Physics, Helsinki University of Technology (Finland); Look, D.C. [Semiconductor Research Center, Wright State University, Dayton, Ohio (United States)

    2004-08-01

    We have used positron annihilation spectroscopy to study the point defects induced by 2 MeV electron irradiation (fluence 6 x 10{sup 17} cm{sup -2}) in single crystal n-type ZnO samples. The positron lifetime measurements have shown that the zinc vacancies in their doubly negative charge state, which act as dominant compensating centers in the as-grown material, are produced in the irradiation and their contribution to the electrical compensation is important. The lifetime measurements reveal also the presence of competing positron traps with low binding energy and lifetime close to that of the bulk lattice. The analysis of the Doppler broadening of the 511 keV annihilation line indicates that these defects can be identified as neutral oxygen vacancies. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Radiation-induced segregation: A microchemical gauge to quantify fundamental defect parameters

    International Nuclear Information System (INIS)

    Simonen, E.P.; Bruemmer, S.M.

    1994-12-01

    Defect Kinetic are evaluated for austenitic stainless alloys by comparing model predictions to measured responses for radiation-induced grain boundary segregation. Heavy-ions, neutrons and proton irradiations having substantial statistical bases are examined. The combined modeling and measurement approach is shown to be useful for quantifying fundamental defect parameters. The mechanism evaluation indicates vacancy, migration energies of 1.15 eV or less and a vacancy formation energy at grain boundaries of 1.5 eV. Damage efficiencies of about 0.03 were established for heavy-ions and for light-water reactor neutrons. Inferred proton damage efficiencies were about 0.15. Segregation measured in an advanced gas-cooled reactor component was much greater than expected using the above parameters

  18. Radiation induced deep level defects in bipolar junction transistors under various bias conditions

    International Nuclear Information System (INIS)

    Liu, Chaoming; Yang, Jianqun; Li, Xingji; Ma, Guoliang; Xiao, Liyi; Bollmann, Joachim

    2015-01-01

    Bipolar junction transistor (BJT) is sensitive to ionization and displacement radiation effects in space. In this paper, 35 MeV Si ions were used as irradiation source to research the radiation damage on NPN and PNP bipolar transistors. The changing of electrical parameters of transistors was in situ measured with increasing irradiation fluence of 35 MeV Si ions. Using deep level transient spectroscopy (DLTS), defects in the bipolar junction transistors under various bias conditions are measured after irradiation. Based on the in situ electrical measurement and DLTS spectra, it is clearly that the bias conditions can affect the concentration of deep level defects, and the radiation damage induced by heavy ions.

  19. Analysis of genetic variation of inducible nitric oxide synthase and ...

    African Journals Online (AJOL)

    The genetic diversity of 100 Malaysian native chickens was investigated using polymerase chain reaction-restriction fragment polymorphism (PCR-RFLP) for two candidate genes: inducible nitric oxide synthase (INOS) and natural resistance-associated macrophage protein 1 (NRAMP1). The two genes were selected ...

  20. Maternal obesity and tobacco use modify the impact of genetic variants on the occurrence of conotruncal heart defects.

    Science.gov (United States)

    Tang, Xinyu; Nick, Todd G; Cleves, Mario A; Erickson, Stephen W; Li, Ming; Li, Jingyun; MacLeod, Stewart L; Hobbs, Charlotte A

    2014-01-01

    Conotruncal heart defects (CTDs) are among the most severe birth defects worldwide. Studies of CTDs indicate both lifestyle behaviors and genetic variation contribute to the risk of CTDs. Based on a hybrid design using data from 616 case-parental and 1645 control-parental triads recruited for the National Birth Defects Prevention Study between 1997 and 2008, we investigated whether the occurrence of CTDs is associated with interactions between 921 maternal and/or fetal single nucleotide polymorphisms (SNPs) and maternal obesity and tobacco use. The maternal genotypes of the variants in the glutamate-cysteine ligase, catalytic subunit (GCLC) gene and the fetal genotypes of the variants in the glutathione S-transferase alpha 3 (GSTA3) gene were associated with an elevated risk of CTDs among obese mothers. The risk of delivering infants with CTDs among obese mothers carrying AC genotype for a variant in the GCLC gene (rs6458939) was 2.00 times the risk among those carrying CC genotype (95% confidence interval: 1.41, 2.38). The maternal genotypes of several variants in the glutathione-S-transferase (GST) family of genes and the fetal genotypes of the variants in the GCLC gene interacted with tobacco exposures to increase the risk of CTDs. Our study suggests that the genetic basis underlying susceptibility of the developing heart to the adverse effects of maternal obesity and tobacco use involve both maternal and embryonic genetic variants. These results may provide insights into the underlying pathophysiology of CTDs, and ultimately lead to novel prevention strategies.

  1. Rapid and reliable healing of critical size bone defects with genetically modified sheep muscle.

    Science.gov (United States)

    Liu, F; Ferreira, E; Porter, R M; Glatt, V; Schinhan, M; Shen, Z; Randolph, M A; Kirker-Head, C A; Wehling, C; Vrahas, M S; Evans, C H; Wells, J W

    2015-09-21

    Large segmental defects in bone fail to heal and remain a clinical problem. Muscle is highly osteogenic, and preliminary data suggest that autologous muscle tissue expressing bone morphogenetic protein-2 (BMP-2) efficiently heals critical size defects in rats. Translation into possible human clinical trials requires, inter alia, demonstration of efficacy in a large animal, such as the sheep. Scale-up is fraught with numerous biological, anatomical, mechanical and structural variables, which cannot be addressed systematically because of cost and other practical issues. For this reason, we developed a translational model enabling us to isolate the biological question of whether sheep muscle, transduced with adenovirus expressing BMP-2, could heal critical size defects in vivo. Initial experiments in athymic rats noted strong healing in only about one-third of animals because of unexpected immune responses to sheep antigens. For this reason, subsequent experiments were performed with Fischer rats under transient immunosuppression. Such experiments confirmed remarkably rapid and reliable healing of the defects in all rats, with bridging by 2 weeks and remodelling as early as 3-4 weeks, despite BMP-2 production only in nanogram quantities and persisting for only 1-3 weeks. By 8 weeks the healed defects contained well-organised new bone with advanced neo-cortication and abundant marrow. Bone mineral content and mechanical strength were close to normal values. These data demonstrate the utility of this model when adapting this technology for bone healing in sheep, as a prelude to human clinical trials.

  2. Identification of equilibrium and irradiation-induced defects in nuclear ceramics: electronic structure calculations of defect properties and positron annihilation characteristics

    International Nuclear Information System (INIS)

    Wiktor, Julia

    2015-01-01

    During in-pile irradiation the fission of actinide nuclei causes the creation of large amounts of defects, which affect the physical and chemical properties of materials inside the reactor, in particular the fuel and structural materials. Positron annihilation spectroscopy (PAS) can be used to characterize irradiation induced defects, empty or containing fission products. This non-destructive experimental technique involves detecting the radiation generated during electron-positron annihilation in a sample and deducing the properties of the material studied. As positrons get trapped in open volume defects in solids, by measuring their lifetime and momentum distributions of the annihilation radiation, one can obtain information on the open and the chemical environments of the defects. In this work electronic structure calculations of positron annihilation characteristics were performed using two-component density functional theory (TCDFT). To calculate the momentum distributions of the annihilation radiation, we implemented the necessary methods in the open-source ABINIT program. The theoretical results have been used to contribute to the identification of the vacancy defects in two nuclear ceramics, silicon carbide (SiC) and uranium dioxide (UO 2 ). (author) [fr

  3. Microstructural evolution of radiation induced defects in ZnO during isochronal annealing

    International Nuclear Information System (INIS)

    Brunner, S.; Puff, W.; Balogh, A.G.

    1999-01-01

    In this study the authors discuss the microstructural changes after electron and proton irradiation and the thermal evolution of the radiation induced defects during isochronal annealing. The nominally undoped samples were irradiated either with 3 MeV protons to a fluence of 1.2 x 10 18 p/cm 2 or with 1 MeV electrons to a fluence of 1 x 10 18 e/cm 2 . The investigation was performed with positron lifetime and Doppler-Broadening measurements. The measurements were done at room temperature and in some cases down to 10 K to investigate the thermal dependence of the trapping characteristics of the positrons

  4. DLTS and capacitance transients study of defects induced by neutron irradiation in MOS structures CCD process

    International Nuclear Information System (INIS)

    Ahaitouf, A.; Losson, E.; Charles, J.P.

    1999-01-01

    The aim of this paper is to study neutron irradiation effects on PMOS capacitors and NMOSFETs transistors. The characterization of induced defects was made by capacitance transients C(t) measurements, DLTS spectroscopy, and optical DLTS (ODLTS). DLTS spectra present three peaks due to deep levels created in the semiconductor and two peaks due to minority carrier generation. Two levels are reported in the literature. Two other minority carrier traps have been observed on ODLTS spectra after irradiation. This can explain the decrease of the minority carrier generation lifetime observed by capacitance transients measurements. (authors)

  5. Laser radiation effect on radiation-induced defects in heavy ion tracks in dielectrics

    International Nuclear Information System (INIS)

    Egorov, A.N.; Zhiryakov, B.M.; Kushin, V.V.; Lyapidevskij, V.K.; Khokhlov, N.B.

    1988-01-01

    Possibility of laser radiation resonance effect on radiation-induced defects in heavy ion tracks in dielectric materials is investigated. Absorption spectra in infrared, visible and ultraviolet ranges for cellulose nitrate samples irradiated by 6 MeV/nucleon 58 Ni ions and reactor gamma radiation are measured. Absorption spectra for irradiated and reference samples are presented. Two absorption bands λ 1 =0.33 μm (E 1 =3.9 eV) and λ 2 =0.72 μm (E 2 =1.7 eV) are detected. Etching rate decrease in a track under laser radiation effect is noticed. 3 refs.; 1 fig

  6. Dependence of the saturated light-induced defect density on macroscopic properties of hydrogenated amorphous silicon

    OpenAIRE

    Park, H. R.; Liu, J. Z.; Roca i Cabarrocas, P.; Maruyama, A.; Isomura, M.; Wagner, S.; Abelson, J. R.; Finger, F.

    2008-01-01

    We report a study of the saturated light-induced defect density Ns,sat in 37 hydrogenated (and in part fluorinated) amorphous silicon [a-Si:H(F)] films grown in six different reactors under widely different conditions. Ns,sat was attained by exposing the films to light from a krypton ion laser (λ=647.1 nm). Ns,sat is determined by the constant photocurrent method and lies between 5×1016 and 2×1017 cm−3. Ns,sat drops with decreasing optical gap Eopt and hydrogen content cH, but is not correlat...

  7. Defects in CdSe thin films, induced by high energy electron irradiation

    International Nuclear Information System (INIS)

    Ion, L.; Antohe, S.; Tutuc, D.; Antohe, V.A.; Tazlaoanu, C.

    2004-01-01

    Defects induced in CdSe thin films by high energy electron irradiation are investigated by means of thermally stimulated currents (TSC) spectroscopy. Films were obtained by vacuum deposition from a single source and irradiated with a 5 x 10 13 electrons/cm 2 s -1 beam of 6-MeV energy. It was found that electrical properties of the films are controlled by a deep donor state, located at 0.38 eV below the bottom edge of the conduction band. Parameters of the traps responsible for the recorded TSC peaks were determined. (authors)

  8. Evaluation of defects induced by neutron radiation in reactor pressure vessels steels

    International Nuclear Information System (INIS)

    Lopez Jimenez, J.

    1978-01-01

    We have developed a method for calculating the production of neutron induced defects (depleted zone and crowdions) in ferritic pressure vessel steels for different neutron spectra. They have been analysed both the recoil primary atoms produced by elastic and inelastic collisions with fast neutrons and the ones produced by gamma-ray emission by thermal neutron absorption. Theoretical modelling of increasing in the ductile-brittle transition temperature of ferritic steels has been correlated with experimental data at irradiation temperature up to 400 degree centigree (Author) 15 refs

  9. Defect induced d{sup 0} ferromagnetism in a ZnO grain boundary

    Energy Technology Data Exchange (ETDEWEB)

    Assa Aravindh, Sasikala Devi; Schwingenschloegl, Udo; Roqan, Iman S, E-mail: iman.roqan@kaust.edu.sa [Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 2955-6900 (Saudi Arabia)

    2015-12-14

    Several experimental studies have referred to the grain boundary (GB) defect as the origin of ferromagnetism in zinc oxide (ZnO). However, the mechanism of this hypothesis has never been confirmed. Present study investigates the atomic structure and the effect of point defects in a ZnO GB using the generalized gradient approximation+U approximation. The relaxed GB possesses large periodicity and channels with 8 and 10 numbered atoms having 4 and 3 fold coordination. The Zn vacancy (V{sub Zn}) shows a tendency to be attracted to the GB, relative to the bulk-like region. Although no magnetization is obtained from point defect-free GB, V{sub Zn} induces spin polarization as large as 0.68 μ{sub B}/atom to the O sites at the GB. Ferromagnetic exchange energy >150 eV is obtained by increasing the concentration of V{sub Zn} and by the injection of holes into the system. Electronic structure analysis indicates that the spin polarization without external dopants originates from the O 2p orbitals, a common feature of d{sup 0} semiconductors.

  10. Defect induced d0 ferromagnetism in a ZnO grain boundary

    KAUST Repository

    Devi, Assa Aravindh Sasikala

    2015-12-08

    Several experimental studies have referred to the grain boundary(GB) defect as the origin of ferromagnetism in zinc oxide (ZnO). However, the mechanism of this hypothesis has never been confirmed. Present study investigates the atomic structure and the effect of point defects in a ZnOGB using the generalized gradient approximation+U approximation. The relaxed GB possesses large periodicity and channels with 8 and 10 numbered atoms having 4 and 3 fold coordination. The Znvacancy (VZn) shows a tendency to be attracted to the GB, relative to the bulk-like region. Although no magnetization is obtained from point defect-free GB, VZn induces spin polarization as large as 0.68 μB/atom to the O sites at the GB.Ferromagnetic exchange energy >150 eV is obtained by increasing the concentration of VZn and by the injection of holes into the system. Electronic structure analysis indicates that the spin polarization without external dopants originates from the O 2p orbitals, a common feature of d0semiconductors.

  11. Defect properties of ZnO nanopowders and their modifications induced by remote plasma treatments

    Energy Technology Data Exchange (ETDEWEB)

    Paramo, J A; Peters, R M; Quarles, C A; Strzhemechny, Y M [Physics Department, Texas Christian University, Fort Worth, TX 76129 (United States); Vallejo, H [North Side High School, Fort Worth, TX 79129 (United States)

    2009-11-15

    Photoluminescence (PL) and positron lifetime (LT) measurements were used on several commercial ZnO nanopowders. We observed that sample-to-sample differences in the quality of the powders overshadow any observation of probable size effects. However, the average LT for all nanocrystals is longer than in a bulk sample, consistent with the hypothesis of crystals with surface and subsurface layers rich in defects. Temperature-dependent PL spectra from the ZnO nanopowders were analyzed in detail for the bound-exciton (BEx) range and the numerical fits of the peak positions yielded activation energies that suggested different channels of recombination for the BEx. Also, fits for the full width at half maximum (FWHM) show nonlinear behavior, indicating contribution from surface phonons. We, also, used remote nitrogen and hydrogen plasma treatment on the ZnO nanosystems to manipulate their surface and subsurface defect states. We demonstrated that those plasma species induce a variety of changes in the deep defect visible emission as well as in the BEx luminescence, most likely associated with the surface/subsurface states.

  12. Defect properties of ZnO nanopowders and their modifications induced by remote plasma treatments

    International Nuclear Information System (INIS)

    Paramo, J A; Peters, R M; Quarles, C A; Strzhemechny, Y M; Vallejo, H

    2009-01-01

    Photoluminescence (PL) and positron lifetime (LT) measurements were used on several commercial ZnO nanopowders. We observed that sample-to-sample differences in the quality of the powders overshadow any observation of probable size effects. However, the average LT for all nanocrystals is longer than in a bulk sample, consistent with the hypothesis of crystals with surface and subsurface layers rich in defects. Temperature-dependent PL spectra from the ZnO nanopowders were analyzed in detail for the bound-exciton (BEx) range and the numerical fits of the peak positions yielded activation energies that suggested different channels of recombination for the BEx. Also, fits for the full width at half maximum (FWHM) show nonlinear behavior, indicating contribution from surface phonons. We, also, used remote nitrogen and hydrogen plasma treatment on the ZnO nanosystems to manipulate their surface and subsurface defect states. We demonstrated that those plasma species induce a variety of changes in the deep defect visible emission as well as in the BEx luminescence, most likely associated with the surface/subsurface states.

  13. Annealing of radiation-induced defects in vanadium and vanadium-titanium alloys

    International Nuclear Information System (INIS)

    Leguey, T.

    1996-01-01

    The annealing of defects induced by electron irradiation up to a dose of 6.10 21 m -2 at T<293 K has been investigated in single-crystals of pure vanadium and in vanadium-titanium alloys with compositions 0.3, 1 and 5 at.% Ti using positron annihilation spectroscopy. The recovery of the positron annihilation parameters in V single-crystals indicates that the defect annealing takes place in the temperature range 410-470 K without formation of microvoids for the present irradiation conditions. For the alloys the recovery onset is shifted to 460 K, the width of the annealing stage is gradually broadened with increasing Ti content, and microvoids are formed for annealing temperatures at the end of the recovery stage. The results show that the vacancy release from vacancy-interstitial impurity pairs and subsequent recombination with interstitial loops is the mechanism of the recovery in pure V. For V-Ti alloys, vacancy-Ti-interstitial impurity complexes and vacancy-Ti pairs appear to be the defects responsible for the positron trapping. The broadening of the recovery stage with increasing Ti content indicates that solute Ti is a very effective trap for vacancies in V. (orig.)

  14. X-ray analysis of temperature induced defect structures in boron implanted silicon

    Science.gov (United States)

    Sztucki, M.; Metzger, T. H.; Kegel, I.; Tilke, A.; Rouvière, J. L.; Lübbert, D.; Arthur, J.; Patel, J. R.

    2002-10-01

    We demonstrate the application of surface sensitive diffuse x-ray scattering under the condition of grazing incidence and exit angles to investigate growth and dissolution of near-surface defects after boron implantation in silicon(001) and annealing. Silicon wafers were implanted with a boron dose of 6×1015 ions/cm2 at 32 keV and went through different annealing treatments. From the diffuse intensity close to the (220) surface Bragg peak we reveal the nature and kinetic behavior of the implantation induced defects. Analyzing the q dependence of the diffuse scattering, we are able to distinguish between point defect clusters and extrinsic stacking faults on {111} planes. Characteristic for stacking faults are diffuse x-ray intensity streaks along directions, which allow for the determination of their growth and dissolution kinetics. For the annealing conditions of our crystals, we conclude that the kinetics of growth can be described by an Ostwald ripening model in which smaller faults shrink at the expense of the larger stacking faults. The growth is found to be limited by the self-diffusion of silicon interstitials. After longer rapid thermal annealing the stacking faults disappear almost completely without shrinking, most likely by transformation into perfect loops via a dislocation reaction. This model is confirmed by complementary cross-sectional transmission electron microscopy.

  15. Annealing study on radiation-induced defects in 6H-SiC

    International Nuclear Information System (INIS)

    Pinheiro, M.V.B.; Lingner, T.; Caudepon, F.; Greulich-Weber, S.; Spaeth, J.M.

    2004-01-01

    We present the results of a systematic isochronal annealing investigation of vacancy-related defects in electron-irradiated n-type 6H-SiC:N. A series of 10 samples cut from a commercial wafer and annealed up to 1200 C after electron-irradiation (1.5 x 10 18 cm -3 ) was characterized with photoluminescence (PL), Magnetic circular dichroism of the absorption (MCDA) and conventional electron paramagnetic resonance (EPR). Apart from less stable triplet-related defects which vanished between 150 C and 300 C, the thermal behavior of three radiation-induced defects was studied: the silicon vacancy (V Si ), the carbon-antisite-carbon-vacancy pair (C Si -V C ) and the D1 center. Their annealing behavior showed that the destruction of the isolated V Si between 750 C and 900 C is followed by the formation of thermally more stable C Si -V C pairs, a result that has been theoretically predicted recently. By further heating the samples the C Si -V C pairs are annealed out between 900 C and 1050 C and were followed by an increase in the D1 center concentration. (orig.)

  16. Defect induced d0 ferromagnetism in a ZnO grain boundary

    KAUST Repository

    Devi, Assa Aravindh Sasikala; Schwingenschlö gl, Udo; Roqan, Iman S.

    2015-01-01

    Several experimental studies have referred to the grain boundary(GB) defect as the origin of ferromagnetism in zinc oxide (ZnO). However, the mechanism of this hypothesis has never been confirmed. Present study investigates the atomic structure and the effect of point defects in a ZnOGB using the generalized gradient approximation+U approximation. The relaxed GB possesses large periodicity and channels with 8 and 10 numbered atoms having 4 and 3 fold coordination. The Znvacancy (VZn) shows a tendency to be attracted to the GB, relative to the bulk-like region. Although no magnetization is obtained from point defect-free GB, VZn induces spin polarization as large as 0.68 μB/atom to the O sites at the GB.Ferromagnetic exchange energy >150 eV is obtained by increasing the concentration of VZn and by the injection of holes into the system. Electronic structure analysis indicates that the spin polarization without external dopants originates from the O 2p orbitals, a common feature of d0semiconductors.

  17. Complex genetics of glaucoma: defects in CYP1B1, and not MYOC ...

    Indian Academy of Sciences (India)

    wide, affecting almost 60 million people (Quigley and Bro- man 2006). Defects ... Analysis of the family mem- ... both parents of the proband do not show any symptom of. POAG ... †These authors contributed equally to the work. .... stage of life.

  18. An ultrastructural and immunocytochemical study of a rare genetic sperm tail defect that causes infertility in humans.

    Science.gov (United States)

    Baccetti, Baccio; Bruni, Emanuele; Gambera, Laura; Moretti, Elena; Piomboni, Paola

    2004-08-01

    To characterize and describe the ontogenesis of a rare flagellar defect affecting the whole sperm population of a sterile man. Case report. Regional referral center for male infertility in Siena, Italy. A 28-year-old man with severe asthenozoospermia. Physical and hormonal assays, semen analysis, and testicular biopsy. Semen samples and testicular biopsies were analyzed by light and transmission electron microscopy; immunocytochemical study with anti-beta-tubulin and anti-AKAP 82 antibodies was performed to detect the presence and distribution of proteins. Ultrastructural analysis of ejaculated spermatozoa and testicular biopsy revealed absence of the fibrous sheath in the principal-piece region of the tail. Fibrous sheath-like structures were observed in cytoplasmic residues and residual bodies released by spermatids in the seminiferous epithelium. Other anomalies observed were supplementary axonemes and mitochondrial helix elongation. These features were confirmed by immunocytochemical staining. This rare sperm tail defect, characterized by absence of the fibrous sheath, presence of supplementary axonemes, and an abnormally elongated midpiece, originates in the seminiferous tubules during spermiogenesis, as detected in testicular biopsy sections. These defects occur in the whole sperm population, and therefore a genetic origin could be suggested.

  19. Nonhomologous recombination between defective poliovirus and coxsackievirus genomes suggests a new model of genetic plasticity for picornaviruses.

    Science.gov (United States)

    Holmblat, Barbara; Jégouic, Sophie; Muslin, Claire; Blondel, Bruno; Joffret, Marie-Line; Delpeyroux, Francis

    2014-08-05

    Most of the circulating vaccine-derived polioviruses (cVDPVs) implicated in poliomyelitis outbreaks in Madagascar have been shown to be recombinants between the type 2 poliovirus (PV) strain of the oral polio vaccine (Sabin 2) and another species C human enterovirus (HEV-C), such as type 17 coxsackie A virus (CA17) in particular. We studied intertypic genetic exchanges between PV and non-PV HEV-C by developing a recombination model, making it possible to rescue defective type 2 PV RNA genomes with a short deletion at the 3' end by the cotransfection of cells with defective or infectious CA17 RNAs. We isolated over 200 different PV/CA17 recombinants, using murine cells expressing the human PV receptor (PVR) and selecting viruses with PV capsids. We found some homologous (H) recombinants and, mostly, nonhomologous (NH) recombinants presenting duplications of parental sequences preferentially located in the regions encoding proteins 2A, 2B, and 3A. Short duplications appeared to be stable, whereas longer duplications were excised during passaging in cultured cells or after multiplication in PVR-transgenic mice, generating H recombinants with diverse sites of recombination. This suggests that NH recombination events may be a transient, intermediate step in the generation and selection of the fittest H recombinants. In addition to the classical copy-choice mechanism of recombination thought to generate mostly H recombinants, there may also be a modular mechanism of recombination, involving NH recombinant precursors, shaping the genomes of recombinant enteroviruses and other picornaviruses. Importance: The multiplication of circulating vaccine-derived polioviruses (cVDPVs) in poorly immunized human populations can render these viruses pathogenic, causing poliomyelitis outbreaks. Most cVDPVs are intertypic recombinants between a poliovirus (PV) strain and another human enterovirus, such as type 17 coxsackie A viruses (CA17). For further studies of the genetic exchanges

  20. Genetic polymorphisms of the TYMS gene are not associated with congenital cardiac septal defects in a Han Chinese population.

    Directory of Open Access Journals (Sweden)

    Jian-Yuan Zhao

    Full Text Available BACKGROUND: Clinical research indicates that periconceptional administration of folic acid can reduce the occurrence of congenital cardiac septal defects (CCSDs. The vital roles of folate exhibits in three ways: the unique methyl donor for DNA expression regulation, the de novo biosynthesis of purine and pyrimidine for DNA construction, and the serum homocysteine removal. Thymidylate synthase (TYMS is the solo catalysis enzyme for the de novo synthesis of dTMP, which is the essential precursor of DNA biosynthesis and repair process. To examine the role of TYMS in Congenital Cardiac Septal Defects (CCSDs risk, we investigated whether genetic polymorphisms in the TYMS gene associated with the CCSDs in a Han Chinese population. METHOD: Polymorphisms in the noncoding region of TYMS were identified via direct sequencing in 32 unrelated individuals composed of half CCSDs and half control subjects. Nine SNPs and two insertion/deletion polymorphisms were genotyped from two independent case-control studies involving a total of 529 CCSDs patients and 876 healthy control participants. The associations were examined by both single polymorphism and haplotype tests using logistic regression. RESULT: We found that TYMS polymorphisms were not related to the altered CCSDs risk, and even to the changed risk of VSDs subgroup, when tested in both studied groups separately or in combination. In the haplotype analysis, there were no haplotypes significantly associated with risks for CCSDs either. CONCLUSION: Our results show no association between common genetic polymorphisms of the regulatory region of the TYMS gene and CCSDs in the Han Chinese population.

  1. The acceptability among young Hindus and Muslims of actively ending the lives of newborns with genetic defects.

    Science.gov (United States)

    Kamble, Shanmukh; Ahmed, Ramadan; Sorum, Paul Clay; Mullet, Etienne

    2014-03-01

    To explore the views in non-Western cultures about ending the lives of damaged newborns. 254 university students from India and 150 from Kuwait rated the acceptability of ending the lives of newborns with genetic defects in 54 vignettes consisting of all combinations of four factors: gestational age (term or 7 months); severity of genetic defect (trisomy 21 alone, trisomy 21 with serious morphological abnormalities or trisomy 13 with impending death); the parents' attitude about prolonging care (unknown, in favour or opposed); and the procedure used (withholding treatment, withdrawing it or injecting a lethal substance). Four clusters were identified by cluster analysis and subjected to analysis of variance. Cluster I, labelled 'Never Acceptable', included 4% of the Indians and 59% of the Kuwaitis. Cluster II, 'No Firm Opinion', had little variation in rating from one scenario to the next; it included 38% of the Indians and 18% of the Kuwaitis. In Cluster III, 'Parents' Attitude+Severity+Procedure', all three factors affected the ratings; it was composed of 18% of the Indians and 16% of the Kuwaitis. Cluster IV was called 'Severity+Parents' Attitude' because these had the strongest impact; it was composed of 40% of the Indians and 7% of the Kuwaitis. In accordance with the teachings of Islam versus Hinduism, Kuwaiti students were more likely to oppose ending a newborn's life under all conditions, Indian students more likely to favour it and to judge its acceptability in light of the different circumstances.

  2. Characterization of Transformation-Induced Defects in Nickel Titanium Shape Memory Alloys

    Science.gov (United States)

    Bowers, Matthew L.

    Shape memory alloys have remarkable strain recovery properties that make them ideal candidates for many applications that include devices in the automotive, aerospace, medical, and MEMS industries. Although these materials are widely used today, their performance is hindered by poor dimensional stability resulting from cyclic degradation of the martensitic transformation behavior. This functional fatigue results in decreased work output and cyclic accumulation of permanent strain. To date, few studies have taken a fundamental approach to investigating the interaction between plasticity and martensite growth and propagation, which is vitally important to mitigating functional fatigue in future alloy development. The current work focuses on understanding the interplay of these deformation mechanisms in NiTi-based shape memory alloys under a variety of different thermomechanical test conditions. Micron-scale compression testing of NiTi shape memory alloy single crystals is undertaken in an effort to probe the mechanism of austenite dislocation generation. Mechanical testing is paired with post mortem defect analysis via diffraction contrast scanning transmission electron microscopy (STEM). Accompanied by micromechanics-based modeling of local stresses surrounding a martensite plate, these results demonstrate that the previously existing martensite and resulting austenite dislocation substructure are intimately related. A mechanism of transformation-induced dislocation generation is described in detail. A study of pure and load-biased thermal cycling of bulk polycrystalline NiTi is done for comparison of the transformation behavior and resultant defects to the stress-induced case. Post mortem and in situ STEM characterization demonstrate unique defect configurations in this test mode and STEM-based orientation mapping reveals local crystal rotation with increasing thermal cycles. Changes in both martensite and austenite microstructures are explored. The results for

  3. Characterisation of irradiation-induced defects in ZnO single crystals

    International Nuclear Information System (INIS)

    Prochazka, I; Cizek, J; Lukac, F; Melikhova, O; Valenta, J; Havranek, V; Anwand, W; Skuratov, V A; Strukova, T S

    2016-01-01

    Positron annihilation spectroscopy (PAS) combined with optical methods was employed for characterisation of defects in the hydrothermally grown ZnO single crystals irradiated by 167 MeV Xe 26+ ions to fluences ranged from 3×10 12 to 1×10 14 cm -2 . The positron lifetime (LT), Doppler broadening as well as slow-positron implantation spectroscopy (SPIS) techniques were involved. The ab-initio theoretical calculations were utilised for interpretation of LT results. The optical transmission and photoluminescence measurements were conducted, too. The virgin ZnO crystal exhibited a single component LT spectrum with a lifetime of 182 ps which is attributed to saturated positron trapping in Zn vacancies associated with hydrogen atoms unintentionally introduced into the crystal during the crystal growth. The Xe ion irradiated ZnO crystals have shown an additional component with a longer lifetime of ≈ 360 ps which comes from irradiation-induced larger defects equivalent in size to clusters of ≈10 to 12 vacancies. The concentrations of these clusters were estimated on the basis of combined LT and SPIS data. The PAS data were correlated with irradiation induced changes seen in the optical spectroscopy experiments. (paper)

  4. Characterisation of irradiation-induced defects in ZnO single crystals

    Science.gov (United States)

    Prochazka, I.; Cizek, J.; Lukac, F.; Melikhova, O.; Valenta, J.; Havranek, V.; Anwand, W.; Skuratov, V. A.; Strukova, T. S.

    2016-01-01

    Positron annihilation spectroscopy (PAS) combined with optical methods was employed for characterisation of defects in the hydrothermally grown ZnO single crystals irradiated by 167 MeV Xe26+ ions to fluences ranged from 3×1012 to 1×1014 cm-2. The positron lifetime (LT), Doppler broadening as well as slow-positron implantation spectroscopy (SPIS) techniques were involved. The ab-initio theoretical calculations were utilised for interpretation of LT results. The optical transmission and photoluminescence measurements were conducted, too. The virgin ZnO crystal exhibited a single component LT spectrum with a lifetime of 182 ps which is attributed to saturated positron trapping in Zn vacancies associated with hydrogen atoms unintentionally introduced into the crystal during the crystal growth. The Xe ion irradiated ZnO crystals have shown an additional component with a longer lifetime of ≈ 360 ps which comes from irradiation-induced larger defects equivalent in size to clusters of ≈10 to 12 vacancies. The concentrations of these clusters were estimated on the basis of combined LT and SPIS data. The PAS data were correlated with irradiation induced changes seen in the optical spectroscopy experiments.

  5. Growth Defects in the Dorsal Pallium after Genetically Targeted Ablation of Principal Preplate Neurons and Neuroblasts: A Morphometric Analysis

    Directory of Open Access Journals (Sweden)

    Robin Fisher

    2010-09-01

    Full Text Available The present study delineates the large-scale, organic responses of growth in the dorsal pallium to targeted genetic ablations of the principal PP (preplate neurons of the neocortex. Ganciclovir treatment during prenatal development [from E11 (embryonic age 11 to E13] of mice selectively killed cells with shared S-phase vulnerability and targeted expression of a GPT [golli promoter transgene; GPT linked to HSV-TK (herpes simplex virus-thymidine kinase, τ-eGFP and lacZ reporters] localized in PP neurons and their intermediate progenitor neuroblasts. The volume, area and thickness of the pallium were measured in an E12-P4 (postnatal age 4 longitudinal study with comparisons between ablated (HSV-TK+/0 and control (HSV-TK0/0 littermates. The extent of ablations was also systematically varied, and the effect on physical growth was assessed in an E18 cross-sectional study. The morphological evidence obtained in the present study supports the conclusion that genetically targeted ablations delay the settlement of the principal PP neurons of the dorsal pallium. This leads to progressive and substantial reductions of growth, despite compensatory responses that rapidly replace the ablated cells. These growth defects originate from inductive cellular interactions in the proliferative matrix of the ventricular zone of the pallium, but are amplified by subsequent morphogenic and trophic cellular interactions. The defects persist during the course of prenatal and postnatal development to demonstrate a constrained dose-response relationship with the extent of specific killing of GPT neurons. The defects propagate simultaneously in both the horizontal and vertical cytoarchitectural dimensions of the developing pallium, an outcome that produces a localized shortfall of volume in the telencephalic vesicles.

  6. Minocycline treatment ameliorates interferon-alpha-induced neurogenic defects and depression-like behaviors in mice

    Directory of Open Access Journals (Sweden)

    Lian-Shun eZheng

    2015-01-01

    Full Text Available Interferon-alpha (IFN-α is a proinflammatory cytokine that is widely used for the treatment of chronic viral hepatitis and malignancy, because of its immune-activating, antiviral, and antiproliferative properties. However, long-term IFN-α treatment frequently causes depression, which limits its clinical utility. The precise molecular and cellular mechanisms of IFN-α-induced depression are not currently understood. Neural stem cells (NSCs in the hippocampus continuously generate new neurons, and some evidence suggests that decreased neurogenesis plays a role in the neuropathology of depression. We previously reported that IFN-α treatment suppressed hippocampal neurogenesis and induced depression-like behaviors via its receptors in the brain in adult mice. However, it is unclear how systemic IFN-α administration induces IFN-α signaling in the hippocampus. In this study, we analyzed the role of microglia, immune cells in the brain, in mediating the IFN-α-induced neurogenic defects and depressive behaviors. In vitro studies demonstrated that IFN-α treatment induced the secretion of endogenous IFN-α from microglia, which suppressed NSC proliferation. In vivo treatment of adult mice with IFN-α for five weeks increased the production of proinflammatory cytokines, including IFN-α, and reduced neurogenesis in the hippocampus. Both effects were prevented by simultaneous treatment with minocycline, an inhibitor of microglial activation. Furthermore, minocycline treatment significantly suppressed IFN-α-induced depressive behaviors in mice. These results suggest that microglial activation plays a critical role in the development of IFN-α-induced depression, and that minocycline is a promising drug for the treatment of IFN-α-induced depression in patients, especially those who are low responders to conventional antidepressant treatments.

  7. Taurine protects methamphetamine-induced developmental angiogenesis defect through antioxidant mechanism

    International Nuclear Information System (INIS)

    Shao, Xue; Hu, Zhengtao; Hu, Chunyan; Bu, Qian; Yan, Guangyan; Deng, Pengchi; Lv, Lei; Wu, Dan; Deng, Yi; Zhao, Jinxuan; Zhu, Ruiming; Li, Yan; Li, Hongyu; Xu, Youzhi; Yang, Hanshuo; Zhao, Yinglan; Cen, Xiaobo

    2012-01-01

    Investigations have characterized addictive drug-induced developmental cardiovascular malformation in human, non-human primate and rodent. However, the underlying mechanism of malformation caused by drugs during pregnancy is still largely unknown, and preventive and therapeutic measures have been lacking. Using 1 H NMR spectroscopy, we profiled the metabolites from human embryo endothelial cells exposed to methamphetamine (METH) and quantified a total of 226 peaks. We identified 11 metabolites modified robustly and found that taurine markedly increased. We then validated the hypothesis that this dramatic increase in taurine could attribute to its effect in inhibiting METH-induced developmental angiogenesis defect. Taurine supplement showed a more significant potential than other metabolites in protecting against METH-induced injury in endothelial cells. Taurine strongly attenuated METH-induced inhibition of proliferation and migration in endothelial cells. Furthermore, death rate and vessel abnormality of zebrafish embryos treated with METH were greatly reversed by taurine. In addition, taurine supplement caused a rapid decrease in reactive oxygen species generation and strongly attenuated the excitable arise of antioxidase activities in the beginning of METH exposure prophase. Dysregulations of NF-κB, p-ERK as well as Bax, which reflect apoptosis, cell cycle arrest and oxidative stress in vascular endothelium, were blocked by taurine. Our results provide the first evidence that taurine prevents METH-caused developmental angiogenesis defect through antioxidant mechanism. Taurine could serve as a potential therapeutic or preventive intervention of developmental vascular malformation for the pregnant women with drug use. Highlights: ► Metabonomics findings. ► Abnormal development. ► Dysregulations of key proteins.

  8. Taurine protects methamphetamine-induced developmental angiogenesis defect through antioxidant mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Xue; Hu, Zhengtao; Hu, Chunyan; Bu, Qian; Yan, Guangyan [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China); Deng, Pengchi [Analytical and Testing Center, Sichuan University, Chengdu 610041 (China); Lv, Lei [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China); Wu, Dan [College of Basic and Forensic Medicine, Sichuan University, Chengdu 610041 (China); Deng, Yi; Zhao, Jinxuan; Zhu, Ruiming; Li, Yan; Li, Hongyu; Xu, Youzhi; Yang, Hanshuo; Zhao, Yinglan [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China); Cen, Xiaobo, E-mail: xbcenalan@vip.sina.com [National Chengdu Center for Safety Evaluation of Drugs, State Key Lab of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041 (China)

    2012-05-01

    Investigations have characterized addictive drug-induced developmental cardiovascular malformation in human, non-human primate and rodent. However, the underlying mechanism of malformation caused by drugs during pregnancy is still largely unknown, and preventive and therapeutic measures have been lacking. Using {sup 1}H NMR spectroscopy, we profiled the metabolites from human embryo endothelial cells exposed to methamphetamine (METH) and quantified a total of 226 peaks. We identified 11 metabolites modified robustly and found that taurine markedly increased. We then validated the hypothesis that this dramatic increase in taurine could attribute to its effect in inhibiting METH-induced developmental angiogenesis defect. Taurine supplement showed a more significant potential than other metabolites in protecting against METH-induced injury in endothelial cells. Taurine strongly attenuated METH-induced inhibition of proliferation and migration in endothelial cells. Furthermore, death rate and vessel abnormality of zebrafish embryos treated with METH were greatly reversed by taurine. In addition, taurine supplement caused a rapid decrease in reactive oxygen species generation and strongly attenuated the excitable arise of antioxidase activities in the beginning of METH exposure prophase. Dysregulations of NF-κB, p-ERK as well as Bax, which reflect apoptosis, cell cycle arrest and oxidative stress in vascular endothelium, were blocked by taurine. Our results provide the first evidence that taurine prevents METH-caused developmental angiogenesis defect through antioxidant mechanism. Taurine could serve as a potential therapeutic or preventive intervention of developmental vascular malformation for the pregnant women with drug use. Highlights: ► Metabonomics findings. ► Abnormal development. ► Dysregulations of key proteins.

  9. Arsenate-induced maternal glucose intolerance and neural tube defects in a mouse model

    International Nuclear Information System (INIS)

    Hill, Denise S.; Wlodarczyk, Bogdan J.; Mitchell, Laura E.; Finnell, Richard H.

    2009-01-01

    Background: Epidemiological studies have linked environmental arsenic (As) exposure to increased type 2 diabetes risk. Periconceptional hyperglycemia is a significant risk factor for neural tube defects (NTDs), the second most common structural birth defect. A suspected teratogen, arsenic (As) induces NTDs in laboratory animals. Objectives: We investigated whether maternal glucose homeostasis disruption was responsible for arsenate-induced NTDs in a well-established dosing regimen used in studies of arsenic's teratogenicity in early neurodevelopment. Methods: We evaluated maternal intraperitoneal (IP) exposure to As 9.6 mg/kg (as sodium arsenate) in LM/Bc/Fnn mice for teratogenicity and disruption of maternal plasma glucose and insulin levels. Selected compounds (insulin pellet, sodium selenate (SS), N-acetyl cysteine (NAC), L-methionine (L-Met), N-tert-Butyl-α-phenylnitrone (PBN)) were investigated for their potential to mitigate arsenate's effects. Results: Arsenate caused significant glucose elevation during an IP glucose tolerance test (IPGTT). Insulin levels were not different between arsenate and control dams before (arsenate, 0.55 ng/dl; control, 0.48 ng/dl) or after glucose challenge (arsenate, 1.09 ng/dl; control, 0.81 ng/dl). HOMA-IR index was higher for arsenate (3.9) vs control (2.5) dams (p = 0.0260). Arsenate caused NTDs (100%, p < 0.0001). Insulin pellet and NAC were the most successful rescue agents, reducing NTD rates to 45% and 35%. Conclusions: IPGTT, insulin assay, and HOMA-IR results suggest a modest failure of glucose stimulated insulin secretion and insulin resistance characteristic of glucose intolerance. Insulin's success in preventing arsenate-induced NTDs provides evidence that these arsenate-induced NTDs are secondary to elevated maternal glucose. The NAC rescue, which did not restore maternal glucose or insulin levels, suggests oxidative disruption plays a role.

  10. Investigation of Near-Surface Defects Induced by Spike Rapid Thermal Annealing in c-SILICON Solar Cells

    Science.gov (United States)

    Liu, Guodong; Ren, Pan; Zhang, Dayong; Wang, Weiping; Li, Jianfeng

    2016-01-01

    The defects induced by a spike rapid thermal annealing (RTA) process in crystalline silicon (c-Si) solar cells were investigated by the photoluminescence (PL) technique and the transmission electron microscopy (TEM), respectively. Dislocation defects were found to form in the near-surface junction region of the monocrystalline Si solar cell after a spike RTA process was performed at 1100∘C. Photo J-V characteristics were measured on the Si solar cell before and after the spike RTA treatments to reveal the effects of defects on the Si cell performances. In addition, the Silvaco device simulation program was used to study the effects of defects density on the cell performances by fitting the experimental data of RTA-treated cells. The results demonstrate that there was an obvious degradation in the Si solar cell performances when the defect density after the spike RTA treatment was above 1×1013cm-3.

  11. Characterization of deep level defects in Tl6I4S single crystals by photo-induced current transient spectroscopy

    International Nuclear Information System (INIS)

    Peters, J A; Liu, Z; Sebastian, M; Wessels, B W; Im, J; Freeman, A J; Nguyen, S; Kanatzidis, M G

    2015-01-01

    Defect levels in semi-insulating Tl 6 I 4 S single crystals grown by the horizontal Bridgman technique have been characterized using photo-induced current transient spectroscopy (PICTS). These measurements revealed six electron traps located at (0.059  ±  0.007), (0.13  ±  0.012), (0.31  ±  0.074), (0.39  ±  0.019), (0.62  ±  0.110), and (0.597  ±  0.105). These defect levels are attributed to vacancies (V I , V S ) and antisite defects (I S , Tl S , Tl I ) upon comparison to calculations of native defect energy levels using density functional theory and defects recently reported from photoluminescence and photoconductivity measurements. (paper)

  12. Radition-induced genetic damage in plutella xylostella

    International Nuclear Information System (INIS)

    Ismail bin Bahari; Mahani binti Mohamad

    1993-01-01

    Radiation-induced chromosomal aberrations in progenies of irradiated Plutella xylostella was determined in a F1 sterility study. A total of 4 types of crosses (irradiated males against unirradiated females, irradiated females against unirradiated males, both parents irradiated and normal) were made following gamma irradiation at the pupal stage. Testes squash preparations made from F1 male larvae revealed 3 main types of chromosomal abberations induced by doses of 100, 150 and 200 Gy. Results obtained indicate the possibility of using chromosome translocations as the genetic marker

  13. Genetic improvement of Sesamun indicum through induced mutations

    International Nuclear Information System (INIS)

    Rajput, M.A.; Khan, Z.H.; Jafri, K.A.; Fazal Ali, J.A.

    2001-01-01

    Pakistan is chronically deficient in the production of edible oils. To enhance local production of edible oils, a mutation breeding project entitled ''Genetic improvement of Sesamum indicum through induced mutations'' was initiated for developing high yielding and widely adapted varieties of sesame. Quite a few mutants having earliness, short stature, semi-indehiscence, compact plant type, heavy bearing and high seed yield have been developed. The true breeding mutant lines developed have exhibited impressive yield potential. (author)

  14. Flux pinning by heavy-ion-irradiation induced linear defects in YBa2Cu3O7 epitaxial films

    International Nuclear Information System (INIS)

    Budhani, R.C.; Zhu, Y.; Suenaga, M.

    1992-01-01

    We report some transport measurements carried out to study flux pinning by heavy-ion-irradiation induced linear defects in Y 1 Ba 2 Cu 3 O 7 films. Our results show that in these in situ deposited films containing a large concentration of defects frozen-in at the time of film growth, a marginal enhancement in critical current density occurs when the density of linear defects 10 /cm 2 , and their diameter of the order of coherence length. This criterion is satisfied by Ag +21 ions. The damage due to Au +24 ions is much too severe to improve the J c

  15. Genetic Syndromes Associated with Congenital Cardiac Defects and Ophthalmologic Changes - Systematization for Diagnosis in the Clinical Practice.

    Science.gov (United States)

    Oliveira, Priscila H A; Souza, Beatriz S; Pacheco, Eimi N; Menegazzo, Michele S; Corrêa, Ivan S; Zen, Paulo R G; Rosa, Rafael F M; Cesa, Claudia C; Pellanda, Lucia C; Vilela, Manuel A P

    2018-01-01

    Numerous genetic syndromes associated with heart disease and ocular manifestations have been described. However, a compilation and a summarization of these syndromes for better consultation and comparison have not been performed yet. The objective of this work is to systematize available evidence in the literature on different syndromes that may cause congenital heart diseases associated with ocular changes, focusing on the types of anatomical and functional changes. A systematic search was performed on Medline electronic databases (PubMed, Embase, Cochrane, Lilacs) of articles published until January 2016. Eligibility criteria were case reports or review articles that evaluated the association of ophthalmic and cardiac abnormalities in genetic syndrome patients younger than 18 years. The most frequent genetic syndromes were: Down Syndrome, Velo-cardio-facial / DiGeorge Syndrome, Charge Syndrome and Noonan Syndrome. The most associated cardiac malformations with ocular findings were interatrial communication (77.4%), interventricular communication (51.6%), patent ductus arteriosus (35.4%), pulmonary artery stenosis (25.8%) and tetralogy of Fallot (22.5%). Due to their clinical variability, congenital cardiac malformations may progress asymptomatically to heart defects associated with high morbidity and mortality. For this reason, the identification of extra-cardiac characteristics that may somehow contribute to the diagnosis of the disease or reveal its severity is of great relevance.

  16. Genetic Syndromes Associated with Congenital Cardiac Defects and Ophthalmologic Changes - Systematization for Diagnosis in the Clinical Practice

    Directory of Open Access Journals (Sweden)

    Priscila H. A. Oliveira

    Full Text Available Abstract Background: Numerous genetic syndromes associated with heart disease and ocular manifestations have been described. However, a compilation and a summarization of these syndromes for better consultation and comparison have not been performed yet. Objective: The objective of this work is to systematize available evidence in the literature on different syndromes that may cause congenital heart diseases associated with ocular changes, focusing on the types of anatomical and functional changes. Method: A systematic search was performed on Medline electronic databases (PubMed, Embase, Cochrane, Lilacs of articles published until January 2016. Eligibility criteria were case reports or review articles that evaluated the association of ophthalmic and cardiac abnormalities in genetic syndrome patients younger than 18 years. Results: The most frequent genetic syndromes were: Down Syndrome, Velo-cardio-facial / DiGeorge Syndrome, Charge Syndrome and Noonan Syndrome. The most associated cardiac malformations with ocular findings were interatrial communication (77.4%, interventricular communication (51.6%, patent ductus arteriosus (35.4%, pulmonary artery stenosis (25.8% and tetralogy of Fallot (22.5%. Conclusion: Due to their clinical variability, congenital cardiac malformations may progress asymptomatically to heart defects associated with high morbidity and mortality. For this reason, the identification of extra-cardiac characteristics that may somehow contribute to the diagnosis of the disease or reveal its severity is of great relevance.

  17. Computer experiment studies on mechanisms for irradiation induced defect production and annealing processes. Final report

    International Nuclear Information System (INIS)

    Beeler, J.R. Jr.; Beeler, M.F.

    1979-06-01

    This research is based on pair potentials used in the Brookhaven work. It extends their use in defect production simulations to the 5 MeV range and characterizes the short term annealing of the primary defect states. Defect properties and interactions are studied. Defect interactions include carbon, helium, and misfit metallic substitutional impurity interactions with vacancy and interstitial defects as well as vacancy-vacancy, interstitial-interstitial and vacancy-interstitial interactions

  18. Computer experiment studies on mechanisms for irradiation induced defect production and annealing processes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Beeler, J.R. Jr.; Beeler, M.F.

    1979-06-01

    This research is based on pair potentials used in the Brookhaven work. It extends their use in defect production simulations to the 5 MeV range and characterizes the short term annealing of the primary defect states. Defect properties and interactions are studied. Defect interactions include carbon, helium, and misfit metallic substitutional impurity interactions with vacancy and interstitial defects as well as vacancy-vacancy, interstitial-interstitial and vacancy-interstitial interactions. (FS)

  19. Genetic Mutations, Birth Lengths, Weights and Head Circumferences of Children with IGF-I Receptor Defects. Comparison with other Congenital Defects in the GH/IGF-I axis.

    Science.gov (United States)

    Essakow, Jenna Lee; Lauterpacht, Aharon; Lilos, Pearl; Kauli, Rivka; Laron, Zvi

    2016-09-01

    In recent years more and more genetic defects along the GHRH-GH-IGF-I axis have been reported. Mutations of the IGF-I receptor (R) are a rare abnormality of whom only the heterozygote progenies survive. To summarize, from the literature, data on birth length, weight and head circumference of neonates with IGF-I-R mutations, and to correlate the data with that of other types of mutations in the GH/IGF-I axis. Sixty seven neonates from 24 published articles were included and forty seven different mutations of the IGF-I (R) located on chromosome 15 have been identified. Mean (±SD) birth length (BL), available for 26, (10 M, 16F) neonates with a gestational age of 34-41weeks, was 44.2±4cm; one was premature (30cm at 31 weeks). There was a significant correlation between birth length and gestational age (GA) r=0.71 (p>.001). Mean birth weight (BW) of 41 neonates (18M, 23F) was 2388±743gr. Two premature neonates weighed 650gr and 950gr respectively. The BW correlated significantly with gestational age, (males: r=0.68; p=0.007, females: r=0.49; p=0.024). The BMI of 25 neonates ranged from 6 to 13. In 22 records marked microcephaly was ascertained or stated. Nine of 16 mothers were short (133 -148cm), m±SD = 150.5±7.3cm. Copyright© of YS Medical Media ltd.

  20. Radiation-induced segregation on defect clusters in single-phase concentrated solid-solution alloys

    International Nuclear Information System (INIS)

    Lu, Chenyang; Yang, Taini; Jin, Ke; Gao, Ning; Xiu, Pengyuan; Zhang, Yanwen; Gao, Fei; Bei, Hongbin; Weber, William J.; Sun, Kai; Dong, Yan; Wang, Lumin

    2017-01-01

    A group of single-phase concentrated solid-solution alloys (SP-CSAs), including NiFe, NiCoFe, NiCoFeCr, as well as a high entropy alloy NiCoFeCrMn, was irradiated with 3 MeV Ni"2"+ ions at 773 K to a fluence of 5 × 10"1"6 ions/cm"2 for the study of radiation response with increasing compositional complexity. Advanced transmission electron microscopy (TEM) with electron energy loss spectroscopy (EELS) was used to characterize the dislocation loop distribution and radiation-induced segregation (RIS) on defect clusters in the SP-CSAs. The results show that a higher fraction of faulted loops exists in the more compositionally complex alloys, which indicate that increasing compositional complexity can extend the incubation period and delay loop growth. The RIS behaviors of each element in the SP-CSAs were observed as follows: Ni and Co tend to enrich, but Cr, Fe and Mn prefer to deplete near the defect clusters. RIS level can be significantly suppressed by increasing compositional complexity due to the sluggish atom diffusion. According to molecular static (MS) simulations, “disk” like segregations may form near the faulted dislocation loops in the SP-CSAs. Segregated elements tend to distribute around the whole faulted loop as a disk rather than only around the edge of the loop.

  1. Ectopic expression of Ptf1a induces spinal defects, urogenital defects, and anorectal malformations in Danforth's short tail mice.

    Directory of Open Access Journals (Sweden)

    Kei Semba

    Full Text Available Danforth's short tail (Sd is a semidominant mutation on mouse chromosome 2, characterized by spinal defects, urogenital defects, and anorectal malformations. However, the gene responsible for the Sd phenotype was unknown. In this study, we identified the molecular basis of the Sd mutation. By positional cloning, we identified the insertion of an early transposon in the Sd candidate locus approximately 12-kb upstream of Ptf1a. We found that insertion of the transposon caused overexpression of three neighboring genes, Gm13344, Gm13336, and Ptf1a, in Sd mutant embryos and that the Sd phenotype was not caused by disruption of an as-yet-unknown gene in the candidate locus. Using multiple knockout and knock-in mouse models, we demonstrated that misexpression of Ptf1a, but not of Gm13344 or Gm13336, in the notochord, hindgut, cloaca, and mesonephros was sufficient to replicate the Sd phenotype. The ectopic expression of Ptf1a in the caudal embryo resulted in attenuated expression of Cdx2 and its downstream target genes T, Wnt3a, and Cyp26a1; we conclude that this is the molecular basis of the Sd phenotype. Analysis of Sd mutant mice will provide insight into the development of the spinal column, anus, and kidney.

  2. Energy and orientation dependence of electron-irradiation-induced defects in InP

    International Nuclear Information System (INIS)

    Sibille, A.; Suski, J.; LeRoux, G.

    1984-01-01

    The concentration of several electron-irradiation-induced deep defect levels in InP has been measured by deep-level transient spectroscopy (DLTS) as a function of electron energy. The dominant centers exhibit a threshold at about 100 keV, which clearly points to a primary production event by electron--phosphorus-atom collision. This unambiguous determination allowed a test of the recently proposed orientation dependence technique to find the nature of the sublattice involved in the collision process for III-V compounds. A good quantitative agreement is obtained with a hard-sphere model for secondary collisions if disorientation of the beam in the sample is taken into account. Other traps exhibit higher thresholds which correspond either to indium-atom displacements or to the involvement of secondary collisions in the production event

  3. Inhomogeneous ozone doping and heat induced defects in graphene studied by infrared near-field microscopy

    Science.gov (United States)

    Wang, Wenjie; Zhang, Jiawei; Deng, Haiming; Liu, Megnkun; Xu, Du

    With the potential use of surface plasmon such as transfer data many orders faster than traditional wires, it has been very popular in research. The fact is that the wavelength of of plasmon is much shorter than the one of free space radiation. The UV ozone doping level can be fine controlled in room temperature creating selected plasmon circuit. We study inhomogeneous graphene plasmonics in ozone doped graphene using scattering-type scanning near-field infrared microscopy and spectroscopy. The single layer and bilayer graphene are doped with different dosage of ozone under UV exposure, which lead to surface inhomogeneity and inhomogeneous graphene plasmon polarition excitation under tip. After annealing the ozone doped graphene in air, the inhomogeneous doping induced plasmons disappear, together with the occurrence of local defects after high temperature annealing.

  4. Study of plasma charging-induced white pixel defect increase in CMOS active pixel sensor

    International Nuclear Information System (INIS)

    Tokashiki, Ken; Bai, KeunHee; Baek, KyeHyun; Kim, Yongjin; Min, Gyungjin; Kang, Changjin; Cho, Hanku; Moon, Jootae

    2007-01-01

    Plasma process-induced 'white pixel defect' (WPD) of CMOS active pixel sensor (APS) is studied for Si3N4 spacer etch back process by using a magnetically enhanced reactive ion etching (MERIE) system. WPD preferably takes place at the wafer edge region when the magnetized plasma is applied to Si3N4 etch. Plasma charging analysis reveals that the plasma charge-up characteristic is well matching the edge-intensive WPD generation, rather than the UV radiation. Plasma charging on APS transfer gate might lead to a gate leakage, which could play a role in generation of signal noise or WPD. In this article the WPD generation mechanism will be discussed from plasma charging point of view

  5. Magnetic circular dichroism study of electron-irradiation induced defects in InP

    International Nuclear Information System (INIS)

    Gislason, H.P.

    1989-01-01

    A strong magnetic circular dichroism (MCD) absorption band centered at 1.07 eV in electron irradiated InP is reported. Temperature and magnetic field dependence of the signal reveal that the centre giving rise to this band is a spin triplet. By simulating neutral and reverse bias conditions of junction measurements through a careful choice of irradiation dose and starting material, the MCD band is shown to have an annealing behaviour closely resembling that of the majority carrier traps which control the Fermi level position in n- and p-type InP. The 1.07 eV MCD band represents the first magneto-optical signal connected with this family of complex irradiation-induced defects in InP. (author) 19 refs., 5 figs., 1 tab

  6. Dynamics of defect-induced dark solitons in an exciton-polariton condensate

    Science.gov (United States)

    Opala, Andrzej; Pieczarka, Maciej; Bobrovska, Nataliya; Matuszewski, Michał

    2018-04-01

    We study theoretically the emission of dark solitons induced by a moving defect in a nonresonantly pumped exciton-polariton condensate. The number of created dark solitons per unit of time is found to be strongly dependent on the pump power. We relate the observed dynamics of this process to the oscillations of the drag force experienced by the condensate. We investigate the stability of the polariton quantum fluid and present various types of dynamics depending on the condensate and moving obstacle parameters. Furthermore, we provide analytical expressions for dark soliton dynamics using the variational method adapted to the nonequilibrium polariton system. The determined dynamical equations are found to be in excellent agreement with the results of numerical simulations.

  7. Induced Pluripotent Stem Cell Models of Progranulin-Deficient Frontotemporal Dementia Uncover Specific Reversible Neuronal Defects

    Directory of Open Access Journals (Sweden)

    Sandra Almeida

    2012-10-01

    Full Text Available The pathogenic mechanisms of frontotemporal dementia (FTD remain poorly understood. Here we generated multiple induced pluripotent stem cell lines from a control subject, a patient with sporadic FTD, and an FTD patient with a novel heterozygous GRN mutation (progranulin [PGRN] S116X. In neurons and microglia differentiated from PGRN S116X induced pluripotent stem cells, the levels of intracellular and secreted PGRN were reduced, establishing patient-specific cellular models of PGRN haploinsufficiency. Through a systematic screen of inducers of cellular stress, we found that PGRN S116X neurons, but not sporadic FTD neurons, exhibited increased sensitivity to staurosporine and other kinase inhibitors. Moreover, the serine/threonine kinase S6K2, a component of the phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways, was specifically downregulated in PGRN S116X neurons. Both increased sensitivity to kinase inhibitors and reduced S6K2 were rescued by PGRN expression. Our findings identify cell-autonomous, reversible defects in patient neurons with PGRN deficiency, and provide a compelling model for studying PGRN-dependent pathogenic mechanisms and testing potential therapies.

  8. Confocal fluorescence microscopy investigation of visible emitting defects induced by electron beam lithography in LIF films

    Energy Technology Data Exchange (ETDEWEB)

    Montereali, R.M.; Bigotta, S.; Pace, A.; Piccinini, M. [ENEA, Divisione Fisica Applicata, Centro Ricerche Frascati, Frascati, RM (Italy); Burattini, E.; Grilli, A.; Raco, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Fisica, Frascati, Rome (Italy); Giammatteo, M. [Unita' Istituto Nazionale di Fisica Nucleare, Frascati, RM (Italy)]|[L' Aquila Univ., L' Aquila (Italy). Centro di Microscopia Elettronica; Picozzi, P.; Santucci, S. [Unita' Istituto Nazionale di Fisica Nucleare, Frascati, RM (Italy)]|[L' Aquila Univ., L' Aquila (Italy). Dipt. di Fisica

    2000-07-01

    Low energy electron irradiation of lithium fluoride (LiF), in the form of bulk crystals and films, gives rise to the stable formation of primary F defects and aggregated color centers in a thin layer located at the surface of the investigated material. For the first time a confocal light scanning microscope (CLSM) in fluorescence mode was used to reconstruct the depth distribution of efficiently emitting laser active color centers in a stripe-like region induced by 12 and 16 keV electrons on LiF films thermally evaporated on glass. The formation of the F{sub 3}{sup +} and F{sub 2} aggregated defects appears restricted to the electron penetration and proportional to their energy depth profile, as obtained from Monte Carlo simulations. [Italian] L'irraggiamento con elettroni di bassa energia del fluoruro di litio (LiF), in forma di cristalli e film, induce la formazione di difetti primari F e centri di colore aggregati stabili in un sottile strato localizzato alla superficie del materiale investigato. Per la prima volta un microscopio confocale a scansione (CLSM) in modalita' fluorescenza e' stato usato per ricostruire la distribuzione di centri di colore laser attivi ad alta efficienza di emissione nel visibile, in strisce colorate ottenute con elettroni da 12 e 16 keV su film di LiF evaporati termicamente su vetro. La formazione dei difetti aggregati F2 e F3+ risulta ristretta spazialmente nella regione di penetrazione degli elettroni e proporzionale al profilo della distribuzione dell'energia da essi depositata, ricavata tramite simulazioni Monte Carlo.

  9. α-Synuclein fibril-induced paradoxical structural and functional defects in hippocampal neurons.

    Science.gov (United States)

    Froula, Jessica M; Henderson, Benjamin W; Gonzalez, Jose Carlos; Vaden, Jada H; Mclean, John W; Wu, Yumei; Banumurthy, Gokulakrishna; Overstreet-Wadiche, Linda; Herskowitz, Jeremy H; Volpicelli-Daley, Laura A

    2018-05-01

    Neuronal inclusions composed of α-synuclein (α-syn) characterize Parkinson's Disease (PD) and Dementia with Lewy bodies (DLB). Cognitive dysfunction defines DLB, and up to 80% of PD patients develop dementia. α-Syn inclusions are abundant in the hippocampus, yet functional consequences are unclear. To determine if pathologic α-syn causes neuronal defects, we induced endogenous α-syn to form inclusions resembling those found in diseased brains by treating hippocampal neurons with α-syn fibrils. At seven days after adding fibrils, α-syn inclusions are abundant in axons, but there is no cell death at this time point, allowing us to assess for potential alterations in neuronal function that are not caused by neuron death. We found that exposure of neurons to fibrils caused a significant reduction in mushroom spine densities, adding to the growing body of literature showing that altered spine morphology is a major pathologic phenotype in synucleinopathies. The reduction in spine densities occurred only in wild type neurons and not in neurons from α-syn knockout mice, suggesting that the changes in spine morphology result from fibril-induced corruption of endogenously expressed α-syn. Paradoxically, reduced postsynaptic spine density was accompanied by increased frequency of miniature excitatory postsynaptic currents (EPSCs) and presynaptic docked vesicles, suggesting enhanced presynaptic function. Action-potential dependent activity was unchanged, suggesting compensatory mechanisms responding to synaptic defects. Although activity at the level of the synapse was unchanged, neurons exposed to α-syn fibrils, showed reduced frequency and amplitudes of spontaneous Ca 2+ transients. These findings open areas of research to determine the mechanisms that alter neuronal function in brain regions critical for cognition at time points before neuron death.

  10. N{sup +} ion-implantation-induced defects in ZnO studied with a slow positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z Q [Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan (Japan); Sekiguchi, T [Nanomaterials Laboratory, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Yuan, X L [Nanomaterials Laboratory, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Maekawa, M [Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan (Japan); Kawasuso, A [Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan (Japan)

    2004-01-21

    Undoped ZnO single crystals were implanted with multiple-energy N{sup +} ions ranging from 50 to 380 keV with doses from 10{sup 12} to 10{sup 14} cm{sup -2}. Positron annihilation measurements show that vacancy defects are introduced in the implanted layers. The concentration of the vacancy defects increases with increasing ion dose. The annealing behaviour of the defects can be divided into four stages, which correspond to the formation and recovery of large vacancy clusters and the formation and disappearance of vacancy-impurity complexes, respectively. All the implantation-induced defects are removed by annealing at 1200 deg. C. Cathodoluminescence measurements show that the ion-implantation-induced defects act as nonradiative recombination centres to suppress the ultraviolet (UV) emission. After annealing, these defects disappear gradually and the UV emission reappears, which coincides with positron annihilation measurements. Hall measurements reveal that after N{sup +} implantation, the ZnO layer still shows n-type conductivity.

  11. Excessive apoptosis and defective autophagy contribute to developmental testicular toxicity induced by fluoride

    International Nuclear Information System (INIS)

    Zhang, Shun; Niu, Qiang; Gao, Hui; Ma, Rulin; Lei, Rongrong; Zhang, Cheng; Xia, Tao; Li, Pei; Xu, Chunyan; Wang, Chao; Chen, Jingwen; Dong, Lixing; Zhao, Qian; Wang, Aiguo

    2016-01-01

    Fluoride, a ubiquitous environmental contaminant, is known to impair testicular functions and fertility; however the underlying mechanisms remain obscure. In this study, we used a rat model to mimic human exposure and sought to investigate the roles of apoptosis and autophagy in testicular toxicity of fluoride. Sprague–Dawley rats were developmentally exposed to 25, 50, or 100 mg/L sodium fluoride (NaF) via drinking water from pre-pregnancy to post-puberty, and then the testes of offspring were excised on postnatal day 56. Our results demonstrated that developmental NaF exposure induced an enhanced testicular apoptosis, as manifested by a series of hallmarks such as caspase-3 activation, chromatin condensation and DNA fragmentation. Further study revealed that fluoride exposure elicited significant elevations in the levels of cell surface death receptor Fas with a parallel increase in cytoplasmic cytochrome c, indicating the involvement of both extrinsic and intrinsic apoptotic pathways. Intriguingly, fluoride treatment also simultaneously increased the number of autophagosomes and the levels of autophagy marker LC3-II but not Beclin1. Unexpectedly, the expression of p62, a substrate that is degraded by autophagy, was also significantly elevated, suggesting that the accumulated autophagosomes resulted from impaired autophagy degradation rather than increased formation. Importantly, these were associated with marked histopathological lesions including spermatogenic failure and germ cell loss, along with severe ultrastructural abnormalities in testes. Taken together, our findings provide deeper insights into roles of excessive apoptosis and defective autophagy in the aggravation of testicular damage, which could contribute to a better understanding of fluoride-induced male reproductive toxicity. - Highlights: • Rats were developmentally exposed to fluoride from pre-pregnancy to post-puberty. • Both excessive apoptosis and defective autophagy are involved in

  12. Wolbachia-induced paternal defect in Drosophila is likely by interaction with the juvenile hormone pathway.

    Science.gov (United States)

    Liu, Chen; Wang, Jia-Lin; Zheng, Ya; Xiong, En-Juan; Li, Jing-Jing; Yuan, Lin-Ling; Yu, Xiao-Qiang; Wang, Yu-Feng

    2014-06-01

    Wolbachia are endosymbionts that infect many insect species. They can manipulate the host's reproduction to increase their own maternal transmission. Cytoplasmic incompatibility (CI) is one such manipulation, which is expressed as embryonic lethality when Wolbachia-infected males mate with uninfected females. However, matings between males and females carrying the same Wolbachia strain result in viable progeny. The molecular mechanisms of CI are currently not clear. We have previously reported that the gene Juvenile hormone-inducible protein 26 (JhI-26) exhibited the highest upregulation in the 3rd instar larval testes of Drosophila melanogaster when infected by Wolbachia. This is reminiscent of an interaction between Wolbachia and juvenile hormone (JH) pathway in flies. Considering that Jhamt gene encodes JH acid methyltransferase, a key regulatory enzyme of JH biosynthesis, and that methoprene-tolerant (Met) has been regarded as the best JH receptor candidate, we first compared the expression of Jhamt and Met between Wolbachia-infected and uninfected fly testes to investigate whether Wolbachia infection influence the JH signaling pathway. We found that the expressions of Jhamt and Met were significantly increased in the presence of Wolbachia, suggesting an interaction of Wolbachia with the JH signaling pathway. Then, we found that overexpression of JhI-26 in Wolbachia-free transgenic male flies caused paternal-effect lethality that mimics the defects associated with CI. JhI-26 overexpressing males resulted in significantly decrease in hatch rate. Surprisingly, Wolbachia-infected females could rescue the egg hatch. In addition, we showed that overexpression of JhI-26 caused upregulation of the male accessory gland protein (Acp) gene CG10433, but not vice versa. This result suggests that JhI-26 may function at the upstream of CG10433. Likewise, overexpression of CG10433 also resulted in paternal-effect lethality. Both JhI-26 and CG10433 overexpressing males

  13. Identification of genetic defects in primary immunodeficiencies by whole exome sequencing

    DEFF Research Database (Denmark)

    Christiansen, Mette; Jensen, Jens Magnus Bernth; Veirum, Jens Erik

    2014-01-01

    to hypogammaglobulinaemia, and increased risk of both infections as well as cancer. We employed whole exome sequencing (WES) to identify mutations associated with primary immunodeficiency in severely affected children. We present WES data on 2 patients with severe immunodeficiency. WES was performed using TruSeq exome kit...... and severe infections including sepsis. Second, we identified compound heterozygote stopgain mutations in RAD52 and a heterozygote mutation in LRRC8A in a 7 year-old girl with T-cell deficiency, reduced T-cell mediated B-cell activity, hypogammaglobulinaemia, prolonged splenomegali and benign adenopathy. RAD......52 has not previously been linked to immunodeficiency and we are currently investigating the functional consequences. Knowledge of the mechanisms underlying immunodeficiencies is a prerequisite for understanding disease pathogenesis. WES allows the demonstration of immune defects that may result from...

  14. Peeling skin syndrome: genetic defects in late terminal differentiation of the epidermis.

    Science.gov (United States)

    Bowden, Paul E

    2011-03-01

    In this issue, Israeli and colleagues confirm that homozygous mutations in corneodesmosin (CDSN) cause type B peeling skin syndrome (PSS), an autosomal recessive skin disorder. The deletion mutation described resulted in a frameshift, producing a downstream premature stop codon and early truncation of the protein. The recently described CDSN nonsense mutation in another PSS family also resulted in protein truncation and nonsense-mediated mRNA decay. Type B generalized PSS can now be clearly distinguished from acral PSS, caused by mutations in transglutaminase 5. This directly affects cornified envelope cross-linking rather than corneodesmosome adherence. These observations provide new insight into the molecular defects underlying two closely related forms of PSS.

  15. Optical spectroscopy and microscopy of radiation-induced light-emitting point defects in lithium fluoride crystals and films

    Science.gov (United States)

    Montereali, R. M.; Bonfigli, F.; Menchini, F.; Vincenti, M. A.

    2012-08-01

    Broad-band light-emitting radiation-induced F2 and F3+ electronic point defects, which are stable and laser-active at room temperature in lithium fluoride crystals and films, are used in dosimeters, tuneable color-center lasers, broad-band miniaturized light sources and novel radiation imaging detectors. A brief review of their photoemission properties is presented, and their behavior at liquid nitrogen temperatures is discussed. Some experimental data from optical spectroscopy and fluorescence microscopy of these radiation-induced point defects in LiF crystals and thin films are used to obtain information about the coloration curves, the efficiency of point defect formation, the effects of photo-bleaching processes, etc. Control of the local formation, stabilization, and transformation of radiation-induced light-emitting defect centers is crucial for the development of optically active micro-components and nanostructures. Some of the advantages of low temperature measurements for novel confocal laser scanning fluorescence microscopy techniques, widely used for spatial mapping of these point defects through the optical reading of their visible photoluminescence, are highlighted.

  16. Genetic analysis of radiation-induced mouse thymic lymphomas

    International Nuclear Information System (INIS)

    Kominami, R.; Wakabayashi, Y.; Niwa, O.

    2003-01-01

    Mouse thymic lymphomas are one of the classic models of radiation-induced malignancies, and the model has been used for the study of genes involved in carcinogenesis. ras oncogenes are the first isolate which undergoes mutations in 10 to 30 % of lymphomas, and p16INK4a and p19ARF in the INK4a-ARF locus are also frequently inactivated. In our previous study, the inactivation of Ikaros, a key regurator of lymphoid system, was found in those lymphomas, and it was suggested that there are other responsible genes yet to be discovered. On the other hand, genetic predisposition to radiation-induced lymphoma often differs in different strains, and this reflects the presence of low penetrance genes that can modify the impact of a given mutation. Little study of such modifiers or susceptibility genes has been performed, either. Recent availability of databases on mouse genome information and the power of mouse genetic system underline usefulness of the lymphoma model in search for novel genes involved, which may provide clues to molecular mechanisms of development of the radiogenic lymphoma and also genes involved in human lymphomas and other malignancies. Accordingly, we have carried out positional cloning for the two different types of tumor-related genes. In this symposium, our current progress is presented that includes genetic mapping of susceptibility/ resistance loci on mouse chromosomes 4, 5 and 19, and also functional analysis of a novel tumor suppressor gene, Rit1/Bcl11b, that has been isolated from allelic loss (LOH) mapping and sequence analysis for γ -ray induced mouse thymic lymphomas

  17. Genetic improvement of 'NPq' rice with induced mutations

    International Nuclear Information System (INIS)

    Ram, Mahabal

    1974-01-01

    Exposure of the seeds of rice to different doses of gamma-rays increased the total mutation frequency with an increase in the dose rate, and the most economic mutations occurred around 30 kr. Induced mutants with dwarf plant type, early maturity, fine grain, high-yielding ability, and resistance to lodging and major diseases were isolated in the M, and M generations. Genetical studies indicated that height is controlled by 4 pairs of additive genes, grass-clumps by 2 pairs of non-allelic interacting genes (inhibitory), and chlorophyll mutations such as albina by 2 pairs of duplicate genes and xantha by a single gene pair. (author)

  18. Ion implantation-induced defects in Oxide Dispersion Strengthened (ODS) steel probed by positron annihilation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Anwand, Wolfgang; Butterling, Maik; Brauer, Gerhard; Wagner, Andreas [HZDR, Institut fuer Strahlenphysik (Germany); Richter, Astrid [Technische Hochschule Wildau (Germany); Koegler, Reinhard [HZDR, Institut fuer Ionenstrahlphysik und Materialforschung (Germany); Chen, C.L. [I-Shou University, Kaohsiung (China)

    2012-07-01

    ODS steel is a promising candidate for an application in fission and fusion power plants of a new generation because of its advantageous properties as stability and temperature resistance. A microscopic understanding of the physical reasons of the mechanical and thermal properties as well as the behaviour of the material under irradiation is an important pre-condition for such applications. The investigated ODS FeCrAl alloy *PM2000* has been produced in a powder metallurgical way. Neutron-induced damage at ODS steel was simulated by He{sup +} and Fe{sup 2+} co-implantation with energies of 2.5 MeV and 400 keV, respectively, and different fluences. The implantation has been carried out with a dual ion beam which enables a simultaneous implantation of both ion types. Thereby the Fe{sup 2+} implantation was used for the creation of radiation defects, and He{sup +} was implanted in order to reproduce He bubbles as they are expected to appear by neutron irradiation. The implantation-induced damage was investigated by depth dependent Doppler broadening measurements using a variable energy slow positron beam.

  19. Induced Pluripotent Stem Cell Models of Progranulin-Deficient Frontotemporal Dementia Uncover Specific Reversible Neuronal Defects

    Science.gov (United States)

    Almeida, Sandra; Zhang, Zhijun; Coppola, Giovanni; Mao, Wenjie; Futai, Kensuke; Karydas, Anna; Geschwind, Michael D.; Tartaglia, M. Carmela; Gao, Fuying; Gianni, Davide; Sena-Esteves, Miguel; Geschwind, Daniel H.; Miller, Bruce L.; Farese, Robert V.; Gao, Fen-Biao

    2012-01-01

    SUMMARY The pathogenic mechanisms of frontotemporal dementia (FTD) remain poorly understood. Here we generated multiple induced pluripotent stem cell (iPSC) lines from a control subject, a patient with sporadic FTD, and an FTD patient with a novel GRN mutation (PGRN S116X). In neurons and microglia differentiated from PGRN S116X iPSCs, the levels of intracellular and secreted progranulin were reduced, establishing patient-specific cellular models of progranulin haploinsufficiency. Through a systematic screen of inducers of cellular stress, we found that PGRN S116X neurons, but not sporadic FTD neurons, exhibited increased sensitivity to staurosporine and other kinase inhibitors. Moreover, the serine/threonine kinase S6K2, a component of the PI3K and MAPK pathways, was specifically downregulated in PGRN S116X neurons. Both increased sensitivity to kinase inhibitors and reduced S6K2 were rescued by progranulin expression. Our findings identify cell-autonomous, reversible defects in patient neurons with progranulin deficiency and provide a new model for studying progranulin-dependent pathogenic mechanisms and testing potential therapies. PMID:23063362

  20. Supplementary Material for: Polyglutamine toxicity in yeast induces metabolic alterations and mitochondrial defects

    KAUST Repository

    Papsdorf, Katharina

    2015-01-01

    Abstract Background Protein aggregation and its pathological effects are the major cause of several neurodegenerative diseases. In Huntingtonâ s disease an elongated stretch of polyglutamines within the protein Huntingtin leads to increased aggregation propensity. This induces cellular defects, culminating in neuronal loss, but the connection between aggregation and toxicity remains to be established. Results To uncover cellular pathways relevant for intoxication we used genome-wide analyses in a yeast model system and identify fourteen genes that, if deleted, result in higher polyglutamine toxicity. Several of these genes, like UGO1, ATP15 and NFU1 encode mitochondrial proteins, implying that a challenged mitochondrial system may become dysfunctional during polyglutamine intoxication. We further employed microarrays to decipher the transcriptional response upon polyglutamine intoxication, which exposes an upregulation of genes involved in sulfur and iron metabolism and mitochondrial Fe-S cluster formation. Indeed, we find that in vivo iron concentrations are misbalanced and observe a reduction in the activity of the prominent Fe-S cluster containing protein aconitase. Like in other yeast strains with impaired mitochondria, non-fermentative growth is impossible after intoxication with the polyglutamine protein. NMR-based metabolic analyses reveal that mitochondrial metabolism is reduced, leading to accumulation of metabolic intermediates in polyglutamine-intoxicated cells. Conclusion These data show that damages to the mitochondrial system occur in polyglutamine intoxicated yeast cells and suggest an intricate connection between polyglutamine-induced toxicity, mitochondrial functionality and iron homeostasis in this model system.

  1. Effect of stacking fault energy on the neutron radiation induced defect accumulation in stainless steels

    International Nuclear Information System (INIS)

    Li Xiaoqiang; Al Mazouzi Abderrahim

    2009-01-01

    Current knowledge highlights the radiation induced segregation (RIS) and the radiation hardening as the two main effects on irradiation assisted stress corrosion cracking (IASCC). Stacking fault energy is considered as a key parameter of materials, which can influence IASCC of stainless steels in nuclear light water reactor (LWR), because it plays an important role in every process of plastic deformation, work hardening and creep behaviour. The study of the impact of SFE variations on the plastic deformation and SCC behaviour of irradiated and unirradiated austenitic steels will contribute to the understanding of IASCC mechanism. The objectives of this work, as a task within the FP6-European Project PERFECT, are to investigate the influence of the SFE on IASCC susceptibility of stainless steels, to correlation n-irradiation induced defect production, accumulation and mechanical deformation behaviour with SFE by using the state of the art experimental tools such as transmission electron microscope (TEM), positron annihilation spectroscopy (PAS), slow strain rate tests (SSRT) in simulated LWR conditions

  2. A Reverse Genetics Approach for the Design of Methyltransferase-Defective Live Attenuated Avian Metapneumovirus Vaccines.

    Science.gov (United States)

    Zhang, Yu; Sun, Jing; Wei, Yongwei; Li, Jianrong

    2016-01-01

    Avian metapneumovirus (aMPV), also known as avian pneumovirus or turkey rhinotracheitis virus, is the causative agent of turkey rhinotracheitis and is associated with swollen head syndrome in chickens. aMPV belongs to the family Paramyxoviridae which includes many important human pathogens such as human respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and human parainfluenza virus type 3 (PIV3). The family also includes highly lethal emerging pathogens such as Nipah virus and Hendra virus, as well as agriculturally important viruses such as Newcastle disease virus (NDV). For many of these viruses, there is no effective vaccine. Here, we describe a reverse genetics approach to develop live attenuated aMPV vaccines by inhibiting the viral mRNA cap methyltransferase. The viral mRNA cap methyltransferase is an excellent target for the attenuation of paramyxoviruses because it plays essential roles in mRNA stability, efficient viral protein translation and innate immunity. We have described in detail the materials and methods used to generate recombinant aMPVs that lack viral mRNA cap methyltransferase activity. We have also provided methods to evaluate the genetic stability, pathogenesis, and immunogenicity of live aMPV vaccine candidates in turkeys.

  3. Parenteral monofluorophosphate (MFP) is a more potent inducer of enamel fluorotic defects in neonatal hamster molars than sodium fluoride

    NARCIS (Netherlands)

    Lyaruu, D.M.; Schoonderwoerd, M.; Tio, D.; Tse, C.; Bervoets, T.J.; Denbesten, P.; Bronckers, A.L.J.J.

    2014-01-01

    Supra-optimal intake of sodium fluoride (NaF) during early childhood results in formation of irreversible enamel defects. Monofluorophosphate (MFP) was considered as less toxic than NaF but equally cariostatic. We compared the potency of MFP and NaF to induce pre-eruptive sub-ameloblastic cysts and

  4. Comparison of naturally occurring and ligature-induced peri-implantitis bone defects in humans and dogs.

    NARCIS (Netherlands)

    Schwarz, F.; Herten, M. van; Sager, M.; Bieling, K.; Sculean, A.; Becker, J.

    2007-01-01

    OBJECTIVES: The aim of the present study was to evaluate and compare naturally occuring and ligature-induced peri-implantitis bone defects in humans and dogs. MATERIAL AND METHODS: Twenty-four partially and fully edentulous patients undergoing peri-implant bone augmentation procedures due to

  5. Combined computational and experimental study of Ar beam induced defect formation in graphite

    International Nuclear Information System (INIS)

    Pregler, Sharon K.; Hayakawa, Tetsuichiro; Yasumatsu, Hisato; Kondow, Tamotsu; Sinnott, Susan B.

    2007-01-01

    Irradiation of graphite, commonly used in nuclear power plants, is known to produce structural damage. Here, experimental and computational methods are used to study defect formation in graphite during Ar irradiation at incident energies of 50 eV. The experimental samples are analyzed with scanning tunneling microscopy to quantify the size distribution of the defects that form. The computational approach is classical molecular dynamic simulations that illustrate the mechanisms by which the defects are produced. The results indicate that defects in graphite grow in concentrated areas and are nucleated by the presence of existing defects

  6. The influence of radiation-induced defects on thermoluminescence and optically stimulated luminescence of α-Al_2O_3:C

    International Nuclear Information System (INIS)

    Nyirenda, A.N.; Chithambo, M.L.

    2017-01-01

    It is known that when α-Al_2O_3:C is exposed to excessive amounts of ionising radiation, defects are induced within its matrix. We report the influence of radiation-induced defects on the thermoluminescence (TL) and optically stimulated luminescence (OSL) measured from α-Al_2O_3:C after irradiation to 1000 Gy. These radiation-induced defects are thermally unstable in the region 450–650 °C and result in TL peaks in this range when the TL is measured at 1 °C/s. Heating a sample to 700 °C obliterates the radiation-induced defects, that is, the TL peaks corresponding to the radiation induced defects are no longer observed in the subsequent TL measurements when moderate irradiation doses below 10 Gy are used. The charge traps associated with these radiation-induced defects are more stable than the dosimetric trap when the sample is exposed to either sunlight or 470-nm blue light from LEDs. TL glow curves measured following the defect-inducing irradiation produce a dosimetric peak that is broader and positioned at a higher temperature than observed in glow curves obtained before the heavy irradiation. In addition, sample sensitization/desensitization occurs due to the presence of these radiation-induced defects. Furthermore, both the activation energy and the kinetic order of the dosimetric peak evaluated when the radiation-induced defects are present in the sample are significantly lower in value than those obtained when these defects are absent. The radiation-induced defects also affect the shape and total light sum of the OSL signal as well as the position and width of the resultant residual phototransferred thermoluminescence main peak.

  7. The influence of radiation-induced defects on thermoluminescence and optically stimulated luminescence of α-Al{sub 2}O{sub 3}:C

    Energy Technology Data Exchange (ETDEWEB)

    Nyirenda, A.N., E-mail: anyirenda@gmail.com; Chithambo, M.L.

    2017-04-15

    It is known that when α-Al{sub 2}O{sub 3}:C is exposed to excessive amounts of ionising radiation, defects are induced within its matrix. We report the influence of radiation-induced defects on the thermoluminescence (TL) and optically stimulated luminescence (OSL) measured from α-Al{sub 2}O{sub 3}:C after irradiation to 1000 Gy. These radiation-induced defects are thermally unstable in the region 450–650 °C and result in TL peaks in this range when the TL is measured at 1 °C/s. Heating a sample to 700 °C obliterates the radiation-induced defects, that is, the TL peaks corresponding to the radiation induced defects are no longer observed in the subsequent TL measurements when moderate irradiation doses below 10 Gy are used. The charge traps associated with these radiation-induced defects are more stable than the dosimetric trap when the sample is exposed to either sunlight or 470-nm blue light from LEDs. TL glow curves measured following the defect-inducing irradiation produce a dosimetric peak that is broader and positioned at a higher temperature than observed in glow curves obtained before the heavy irradiation. In addition, sample sensitization/desensitization occurs due to the presence of these radiation-induced defects. Furthermore, both the activation energy and the kinetic order of the dosimetric peak evaluated when the radiation-induced defects are present in the sample are significantly lower in value than those obtained when these defects are absent. The radiation-induced defects also affect the shape and total light sum of the OSL signal as well as the position and width of the resultant residual phototransferred thermoluminescence main peak.

  8. Genetic improvement of black gram using induced mutations

    International Nuclear Information System (INIS)

    Pawar, S.E.; Manjaya, J.G.; Souframanien, J.; Bhatkar, S.M.

    2000-01-01

    Induced mutagenesis is an important tool for creating genetic variability in crop plants and has played a significant role in the development of many crop varieties. Genetic improvement of black gram (Vigna mungo L. Hepper) through induced mutations has been in progress at BARC for the past three decades. Mutation studies of genotype EC-168200 have resulted in isolating large number of mutants with distinct morphological characters. TAU-5, an early maturing mutant was identified as a resistant donor for yellow mosaic virus (YMV) disease by the All India Pulse Improvement Project, ICAR, Kanpur. TAU-5 was used in cross breeding with elite cultivars like T-9, TPU-4 and LBG-17. Twelve selections with high yield potential suitable for both kharif and rabi cultivation have been developed. One of the selections TU94-2 has been released for commercial cultivation for southern zone during 1999. The work on the development of YMV resistant genotypes is in progress and will be discussed. (author)

  9. MD simulations to evaluate effects of applied tensile strain on irradiation-induced defect production at various PKA energies

    International Nuclear Information System (INIS)

    Miyashiro, S.; Fujita, S.; Okita, T.; Okuda, H.

    2012-01-01

    Highlights: ► Strain effects on defect formation were evaluated at various PKA energies by MD. ► Radiation-induced defects were increased numerically by external strain. ► Enhanced formation of larger clusters causes the numerical increase of defects. ► Strain influence on the number of defects was greatest at about 20 keV PKA. ► Cluster size, which is mostly affected by strain, was greater with higher PKA energy. - Abstract: Molecular Dynamics (MD) simulations were conducted to investigate the influence of applied tensile strain on defect production during cascade damages at various Primary Knock-on Atom (PKA) energies of 1–30 keV. When 1% strain was applied, the number of surviving defects increased at PKA energies higher than 5 keV, although they did not increase at 1 keV. The rate of increase by strain application was higher with higher PKA energy, and attained the maximum at 20 keV PKA energy with a subsequent gradual decrease at 30 keV PKA energy The cluster size, mostly affected by strain, was larger with higher PKA energy, although clusters with fewer than seven interstitials did not increase in number at any PKA energy.

  10. Destruction-polymerization transformations as a source of radiation-induced extended defects in chalcogenide glassy semiconductors

    International Nuclear Information System (INIS)

    Shpotyuk, Oleh; Filipecki, Jacek; Shpotyuk, Mykhaylo

    2013-01-01

    Long-wave shift of the optical transmission spectrum in the region of fundamental optical absorption edge is registered for As 2 S 3 chalcogenide glassy semiconductors after γ-irradiation. This effect is explained in the frameworks of the destruction-polymerization transformations concept by accepting the switching of the heteropolar As-S covalent bonds into homopolar As-As ones. It is assumed that (As 4 + ; S 1 - ) defect pairs are created under such switching. Formula to calculate content of the induced defects in chalcogenide glassy semiconductors is proposed. It is assumed that defects concentration depends on energy of broken covalent bond, bond-switching energy balance, correlation energy, optical band-gap and energy of excitation light. It is shown that theoretically calculated maximally possible content of radiation-induced defects in As 2 S 3 is about 1.6% while concentration of native defects is negligible. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Nonhomologous Recombination between Defective Poliovirus and Coxsackievirus Genomes Suggests a New Model of Genetic Plasticity for Picornaviruses

    Science.gov (United States)

    Holmblat, Barbara; Jégouic, Sophie; Muslin, Claire; Blondel, Bruno; Joffret, Marie-Line

    2014-01-01

    ABSTRACT Most of the circulating vaccine-derived polioviruses (cVDPVs) implicated in poliomyelitis outbreaks in Madagascar have been shown to be recombinants between the type 2 poliovirus (PV) strain of the oral polio vaccine (Sabin 2) and another species C human enterovirus (HEV-C), such as type 17 coxsackie A virus (CA17) in particular. We studied intertypic genetic exchanges between PV and non-PV HEV-C by developing a recombination model, making it possible to rescue defective type 2 PV RNA genomes with a short deletion at the 3′ end by the cotransfection of cells with defective or infectious CA17 RNAs. We isolated over 200 different PV/CA17 recombinants, using murine cells expressing the human PV receptor (PVR) and selecting viruses with PV capsids. We found some homologous (H) recombinants and, mostly, nonhomologous (NH) recombinants presenting duplications of parental sequences preferentially located in the regions encoding proteins 2A, 2B, and 3A. Short duplications appeared to be stable, whereas longer duplications were excised during passaging in cultured cells or after multiplication in PVR-transgenic mice, generating H recombinants with diverse sites of recombination. This suggests that NH recombination events may be a transient, intermediate step in the generation and selection of the fittest H recombinants. In addition to the classical copy-choice mechanism of recombination thought to generate mostly H recombinants, there may also be a modular mechanism of recombination, involving NH recombinant precursors, shaping the genomes of recombinant enteroviruses and other picornaviruses. PMID:25096874

  12. Influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures and lattice defects accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Sedao, Xxx; Garrelie, Florence, E-mail: florence.garrelie@univ-st-etienne.fr; Colombier, Jean-Philippe; Reynaud, Stéphanie; Pigeon, Florent [Université de Lyon, CNRS, UMR5516, Laboratoire Hubert Curien, Université de Saint Etienne, Jean Monnet, F-42023 Saint-Etienne (France); Maurice, Claire; Quey, Romain [Ecole Nationale Supérieure des Mines de Saint-Etienne, CNRS, UMR5307, Laboratoire Georges Friedel, F-42023 Saint-Etienne (France)

    2014-04-28

    The influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures (LIPSS) has been investigated on a polycrystalline nickel sample. Electron Backscatter Diffraction characterization has been exploited to provide structural information within the laser spot on irradiated samples to determine the dependence of LIPSS formation and lattice defects (stacking faults, twins, dislocations) upon the crystal orientation. Significant differences are observed at low-to-medium number of laser pulses, outstandingly for (111)-oriented surface which favors lattice defects formation rather than LIPSS formation.

  13. Type 2 diabetes mellitus induces congenital heart defects in murine embryos by increasing oxidative stress, endoplasmic reticulum stress, and apoptosis.

    Science.gov (United States)

    Wu, Yanqing; Reece, E Albert; Zhong, Jianxiang; Dong, Daoyin; Shen, Wei-Bin; Harman, Christopher R; Yang, Peixin

    2016-09-01

    Maternal type 1 and 2 diabetes mellitus are strongly associated with high rates of severe structural birth defects, including congenital heart defects. Studies in type 1 diabetic embryopathy animal models have demonstrated that cellular stress-induced apoptosis mediates the teratogenicity of maternal diabetes leading to congenital heart defect formation. However, the mechanisms underlying maternal type 2 diabetes mellitus-induced congenital heart defects remain largely unknown. We aim to determine whether oxidative stress, endoplasmic reticulum stress, and excessive apoptosis are the intracellular molecular mechanisms underlying maternal type 2 diabetes mellitus-induced congenital heart defects. A mouse model of maternal type 2 diabetes mellitus was established by feeding female mice a high-fat diet (60% fat). After 15 weeks on the high-fat diet, the mice showed characteristics of maternal type 2 diabetes mellitus. Control dams were either fed a normal diet (10% fat) or the high-fat diet during pregnancy only. Female mice from the high-fat diet group and the 2 control groups were mated with male mice that were fed a normal diet. At E12.5, embryonic hearts were harvested to determine the levels of lipid peroxides and superoxide, endoplasmic reticulum stress markers, cleaved caspase 3 and 8, and apoptosis. E17.5 embryonic hearts were harvested for the detection of congenital heart defect formation using India ink vessel patterning and histological examination. Maternal type 2 diabetes mellitus significantly induced ventricular septal defects and persistent truncus arteriosus in the developing heart, along with increasing oxidative stress markers, including superoxide and lipid peroxidation; endoplasmic reticulum stress markers, including protein levels of phosphorylated-protein kinase RNA-like endoplasmic reticulum kinase, phosphorylated-IRE1α, phosphorylated-eIF2α, C/EBP homologous protein, and binding immunoglobulin protein; endoplasmic reticulum chaperone gene

  14. Study on radiation-induced defects in germanium monocrystals by the X-ray diffusive scattering method

    International Nuclear Information System (INIS)

    Malinenko, I.A.; Perelygina, E.A.; Chudinova, S.A.; Shivrin, O.N.

    1979-01-01

    The method of X-ray diffusion scattering was used to study the defective structure of germanium monocrystals exposed to 750 keV proton irradiation with 3.8x10 16 -4.6x10 17 cm -2 doses and subjected to the subsequent annealing at temperatures up to 450 deg C. Detected in the crystals were the complex radiation induced structure characterized with oriented vacancy complexes and results from the both effects: irradiation and annealing. Radiation defect sizes in the section (hhO) have been determined. With increasing the annealing temperature the structure reconstruction resulting in the complex dissociation is observed

  15. Genetic defects in DNA repair system and enhancement of intergenote transformation efficiency in Bacillus subtilis Marburg

    International Nuclear Information System (INIS)

    Matsumoto, K.; Takahashi, H.; Saito, H.; Ikeda, Y.

    1978-01-01

    Mechanisms of inefficiency in heterospecies transformation were studied with a transformation system consisting of Bacillus subtilis 168TI (trpC2thy) as recipient and of DNA prepared from partially hybrid strains of B. subtilis which had incorporated trp + DNA of B. amyloliquefaciens 203 (formerly, B. megaterium 203) in the chromosome (termed intergenote). The intergenote transformation was not so efficient as the corresponding homospecies transformation and the efficiency appeared to relate inversely with the length of heterologous portion in the intergenote. When a variety of ultraviolet light (UV) sensitive mutants, deficient in host-cell reactivation capacity, were used as recipients for the intergenote transformation, 2 out of 16 mutants exhibited significantly enhanced transformation efficiency of the trpC marker. Genetic studies by transformation showed that the trait relating to the enhancement of intergenote-transformation efficiency was always associated with the UV sensitivity, suggesting that these two traits are determined by a single gene. The efficiency of intergenote transformation was highly affected also by DNA concentration; the lower the concentration, the less the efficiency. When, however, the UV sensitive mutant was used as recipient, the effect of DNA concentration was largely diminished, suggesting the reduction of DNA-inactivating activity in the UV sensitive recipient. These results were discussed in relation to a possible excision-repair system selectively correcting the mismatched DNA in the course of intergenote transformation. (orig.) [de

  16. Defects induced by swift heavy ions in the 18R martensite of Cu-Zn-Al alloy

    International Nuclear Information System (INIS)

    Zelaya, Eugenia; Tolley, Alfredo; Condo, Adriana; Lovey, Francisco; Schumacher, G

    2003-01-01

    The swift heavy ion incidence over the surface of a given material produces a strong energy deposition in a nanometric scale.Swift heavy ions, of the order of one thousand of MeV, deposit their energy as electronic excitations.This highly localized deposition can induce metastable transformations within the material. For example, in martensitic NiTi alloys irradiated with swift heavy ions, it has been observed changes on the martensitic transformation temperature and amorphous areas induced by the irradiation.In this work, the effects produced by swift heavy ions on the martensitic 18R structure of Cu-Zn-Al alloy (Cu - 12.17 Zn - 17.92 Al, in %at) were analyzed.Crystalline samples were irradiated in a direction close to the [2 1 0] of 18R with Xe + 230 MeV, Au + of 350 MeV and Kr + of 200 MeV ion beams.Defects of the order of nanometers induced by the irradiation were observed by transmission electron microscopy (TEM) and high resolution electron microscopy (HREM).It was also observed, that the average size of the irradiation defects induced by Au + ion is larger than those induced by Xe + and Kr + ions.In this case, no relationship between the observed defects and the energy deposition was found in the 23 keV/nn to 48 keV/nn range

  17. On the diffusion process of irradiation-induced point defects in the stress field of a moving dislocation

    International Nuclear Information System (INIS)

    Steinbach, E.

    1987-01-01

    The cellular model of a dislocation is used for an investigation of the time-dependent diffusion process of irradiation-induced point defects interacting with the stress field of a moving dislocation. An analytic solution is given taking into account the elastic interaction due to the first-order size effect and the stress-induced interaction, the kinematic interaction due to the dislocation motion as well as the presence of secondary neutral sinks. The results for the space and time-dependent point defect concentration, represented in terms of Mathieu-Bessel and Mathieu-Hankel functions, emphasize the influence of the parameters which have been taken into consideration. Proceeding from these solutions, formulae for the diffusion flux reaching unit length of the dislocation, which plays an important role with regard to void swelling and irradiation-induced creep, are derived

  18. Piezoelectricity induced defect modes for shear waves in a periodically stratified supperlattice

    Science.gov (United States)

    Piliposyan, Davit

    2018-01-01

    Properties of shear waves in a piezoelectric stratified periodic structure with a defect layer are studied for a superlattice with identical piezoelectric materials in a unit cell. Due to the electro-mechanical coupling in piezoelectric materials the structure exhibits defect modes in the superlattice with full transmission peaks both for full contact and electrically shorted interfaces. The results show an existence of one or two transmission peaks depending on the interfacial conditions. In the long wavelength region where coupling between electro-magnetic and elastic waves creates frequency band gaps the defect layer introduces one or two defect modes transmitting both electro-magnetic and elastic energies. Other parameters affecting the defect modes are the thickness of the defect layer, differences in refractive indexes and the magnitude of the angle of the incident wave. The results of the paper may be useful in the design of narrow band filters or multi-channel piezoelectric filters.

  19. Toward a comprehensive theory of radiation-induced swelling and creep - the point defect concentrations

    International Nuclear Information System (INIS)

    Mansur, L.K.; Yoo, M.H.

    1979-01-01

    The theory of void swelling and irradiation creep is now fairly comprehensive. A unifying concept on which most of this understanding rests is that of the rate theory point defect concentrations. Several basic aspects of this unifying conept are reviewed. These relate to local fluctuations in point defect concentrations produced by cascades, the effects of thermal and radiation-produced divacancies, and the effects of point defect trapping

  20. Histone deacetylase inhibition reduces hypothyroidism-induced neurodevelopmental defects in rats.

    Science.gov (United States)

    Kumar, Praveen; Mohan, Vishwa; Sinha, Rohit Anthony; Chagtoo, Megha; Godbole, Madan M

    2015-11-01

    Thyroid hormone (TH) through its receptor (TRα/β) influences spatio-temporal regulation of its target gene repertoire during brain development. Though hypothyroidism in WT rodent models of perinatal hypothyroidism severely impairs neurodevelopment, its effect on TRα/β knockout mice is less severe. An explanation to this paradox is attributed to a possible repressive action of unliganded TRs during development. Since unliganded TRs suppress gene expression through the recruitment of histone deacetylase (HDACs) via co-repressor complexes, we tested whether pharmacological inhibition of HDACs may prevent the effects of hypothyroidism on brain development. Using valproate, an HDAC inhibitor, we show that HDAC inhibition significantly blocks the deleterious effects of hypothyroidism on rat cerebellum, evident by recovery of TH target genes like Bdnf, Pcp2 and Mbp as well as improved dendritic structure of cerebellar Purkinje neurons. Together with this, HDAC inhibition also rescues hypothyroidism-induced motor and cognitive defects. This study therefore provides an insight into the role of HDACs in TH insufficiency during neurodevelopment and their inhibition as a possible therapeutics for treatment. © 2015 Society for Endocrinology.

  1. Green tea polyphenols rescue of brain defects induced by overexpression of DYRK1A.

    Directory of Open Access Journals (Sweden)

    Fayçal Guedj

    Full Text Available Individuals with partial HSA21 trisomies and mice with partial MMU16 trisomies containing an extra copy of the DYRK1A gene present various alterations in brain morphogenesis. They present also learning impairments modeling those encountered in Down syndrome. Previous MRI and histological analyses of a transgenic mice generated using a human YAC construct that contains five genes including DYRK1A reveal that DYRK1A is involved, during development, in the control of brain volume and cell density of specific brain regions. Gene dosage correction induces a rescue of the brain volume alterations. DYRK1A is also involved in the control of synaptic plasticity and memory consolidation. Increased gene dosage results in brain morphogenesis defects, low BDNF levels and mnemonic deficits in these mice. Epigallocatechin gallate (EGCG - a member of a natural polyphenols family, found in great amount in green tea leaves - is a specific and safe DYRK1A inhibitor. We maintained control and transgenic mice overexpressing DYRK1A on two different polyphenol-based diets, from gestation to adulthood. The major features of the transgenic phenotype were rescued in these mice.

  2. Irradiation-induced defects in graphite and glassy carbon studied by positron annihilation

    International Nuclear Information System (INIS)

    Hasegawa, M.; Kajino, M.; Kuwahara, H.; Yamaguchi, S.; Kuramoto, E.; Takenaka, M.

    1992-01-01

    ACAR and positron lifetime measurements have been made on, HOPG, isotropic fine-grained graphites, glassy carbons and C 60 /C 70 . HOPG showed a marked bimodal ACAR distribution along the c-axis. By irradiation of 1.0 X 10 19 fast neutrons/cm 2 remarkable narrowing in the ACAR curves and disappearance of the bimodal distribution were observed. Lifetime in HOPG increased from 225 psec to 289 psec (positron-lifetime in vacancies and their small clusters) by the irradiation. The irradiation on isotropic graphites and glassy carbons, however, gave slight narrowing in ACAR curves and decrease in lifetimes (360 psec → 300psec). This suggests irradiation-induced vacancy trapping in crystallites. In C 60 /C 70 powder two lifetime components were detected: τ 1 =177psec, τ 2 =403psec (I 2 =58%). The former is less than the bulk lifetime of HOPG, while the latter being very close to lifetimes in the isotropic graphites and glassy carbons. This and recent 2D-ACAR study of HOPG surface [15] strongly suggest free and defect surface states around ''soccer ball'' cages

  3. Simulation of surface crack initiation induced by slip localization and point defects kinetics

    International Nuclear Information System (INIS)

    Sauzay, Maxime; Liu, Jia; Rachdi, Fatima

    2014-01-01

    Crack initiation along surface persistent slip bands (PSBs) has been widely observed and modelled. Nevertheless, from our knowledge, no physically-based fracture modelling has been proposed and validated with respect to the numerous recent experimental data showing the strong relationship between extrusion and microcrack initiation. The whole FE modelling accounts for: - localized plastic slip in PSBs; - production and annihilation of vacancies induced by cyclic slip. If temperature is high enough, point defects may diffuse in the surrounding matrix due to large concentration gradients, allowing continuous extrusion growth in agreement with Polak's model. At each cycle, the additional atoms diffusing from the matrix are taken into account by imposing an incremental free dilatation; - brittle fracture at the interfaces between PSBs and their surrounding matrix which is simulated using cohesive zone modelling. Any inverse fitting of parameter is avoided. Only experimental single crystal data are used such as hysteresis loops and resistivity values. Two fracture parameters are required: the {111} surface energy which depends on environment and the cleavage stress which is predicted by the universal binding energy relationship. The predicted extrusion growth curves agree rather well with the experimental data published for copper and the 316L steel. A linear dependence with respect to PSB length, thickness and slip plane angle is predicted in agreement with recent AFM measurement results. Crack initiation simulations predict fairly well the effects of PSB length and environment for copper single and poly-crystals. (authors)

  4. Modeling of excimer laser radiation induced defect generation in fluoride phosphate glasses

    International Nuclear Information System (INIS)

    Natura, U.; Ehrt, D.

    2001-01-01

    Fluoride phosphate (FP) glasses with low phosphate content are high-transparent in the deep ultraviolet (UV) range and attractive candidates for UV-optics. Their optical properties are complementary to fluoride crystals. The anomalous partial dispersion makes them desirable for optical lens designs to reduce the secondary spectrum. Their UV transmission is limited by trace impurities introduced by raw materials and decreases when exposed to UV-radiation (lamps, lasers). The experiments of the paper published previously in this journal were used in order to separate radiation induced absorption bands in the fluoride phosphate glass FP10. In this paper the generation mechanism of the phosphorus-oxygen related hole center POHC 2 is investigated in detail in glasses of various compositions (various phosphate and impurity contents) in order to predict the transmission loss in case of long-time irradiation. Experiments were carried out using ArF- and KrF-excimer lasers (ns-pulses). POHC 2 generation strongly depends on the phosphate content and on the content of Pb 2+ . A model was developed on these terms. Rate equations are formulated, incorporating the influence of the Pb 2+ -content on the defect generation, a two-step creation term including an energy transfer process and a one-photon bleaching term. This results in a set of coupled nonlinear differential equations. Absorption coefficients and lifetimes of the excited states were calculated as well. Experimental results compared well with the numerical analysis of the theoretical rate equations

  5. Detection of Defect-Induced Magnetism in Low-Dimensional ZnO Structures by Magnetophotocurrent.

    Science.gov (United States)

    Lorite, Israel; Kumar, Yogesh; Esquinazi, Pablo; Zandalazini, Carlos; de Heluani, Silvia Perez

    2015-09-09

    The detection of defect-induced magnetic order in single low-dimensional oxide structures is in general difficult because of the relatively small yield of magnetically ordered regions. In this work, the effect of an external magnetic field on the transient photocurrent measured after light irradiation on different ZnO samples at room temperature is studied. It has been found that a magnetic field produces a change in the relaxation rate of the transient photocurrent only in magnetically ordered ZnO samples. This rate can decrease or increase with field, depending on whether the magnetically ordered region is in the bulk or only at the surface of the ZnO sample. The phenomenon reported here is of importance for the development of magneto-optical low-dimensional oxides devices and provides a new guideline for the detection of magnetic order in low-dimensional magnetic semiconductors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Excessive apoptosis and defective autophagy contribute to developmental testicular toxicity induced by fluoride.

    Science.gov (United States)

    Zhang, Shun; Niu, Qiang; Gao, Hui; Ma, Rulin; Lei, Rongrong; Zhang, Cheng; Xia, Tao; Li, Pei; Xu, Chunyan; Wang, Chao; Chen, Jingwen; Dong, Lixing; Zhao, Qian; Wang, Aiguo

    2016-05-01

    Fluoride, a ubiquitous environmental contaminant, is known to impair testicular functions and fertility; however the underlying mechanisms remain obscure. In this study, we used a rat model to mimic human exposure and sought to investigate the roles of apoptosis and autophagy in testicular toxicity of fluoride. Sprague-Dawley rats were developmentally exposed to 25, 50, or 100 mg/L sodium fluoride (NaF) via drinking water from pre-pregnancy to post-puberty, and then the testes of offspring were excised on postnatal day 56. Our results demonstrated that developmental NaF exposure induced an enhanced testicular apoptosis, as manifested by a series of hallmarks such as caspase-3 activation, chromatin condensation and DNA fragmentation. Further study revealed that fluoride exposure elicited significant elevations in the levels of cell surface death receptor Fas with a parallel increase in cytoplasmic cytochrome c, indicating the involvement of both extrinsic and intrinsic apoptotic pathways. Intriguingly, fluoride treatment also simultaneously increased the number of autophagosomes and the levels of autophagy marker LC3-II but not Beclin1. Unexpectedly, the expression of p62, a substrate that is degraded by autophagy, was also significantly elevated, suggesting that the accumulated autophagosomes resulted from impaired autophagy degradation rather than increased formation. Importantly, these were associated with marked histopathological lesions including spermatogenic failure and germ cell loss, along with severe ultrastructural abnormalities in testes. Taken together, our findings provide deeper insights into roles of excessive apoptosis and defective autophagy in the aggravation of testicular damage, which could contribute to a better understanding of fluoride-induced male reproductive toxicity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Electron irradiation-induced defects in ZnO studied by positron annihilation

    International Nuclear Information System (INIS)

    Chen, Z.Q.; Maekawa, M.; Kawasuso, A.; Sakai, S.; Naramoto, H.

    2006-01-01

    ZnO crystals were subjected to 3 MeV electron irradiation up to a high dose of 5.5x10 18 cm -2 . The production and recovery of vacancy defects were studied by positron annihilation spectroscopy. The increase of positron lifetime and Doppler broadening S parameter after irradiation indicates introduction of V Zn related defects. Most of these vacancies are annealed at temperatures below 200 o C. However, after annealing at around 400 o C, secondary defects are produced. All the vacancy defects are annealed out at around 700 o C

  8. Electron irradiation-induced defects in ZnO studied by positron annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.Q. [Advanced Science Research Center, Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)]. E-mail: zhiquanchen@hotmail.com; Maekawa, M. [Advanced Science Research Center, Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Kawasuso, A. [Advanced Science Research Center, Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Sakai, S. [Advanced Science Research Center, Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Naramoto, H. [Advanced Science Research Center, Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2006-04-01

    ZnO crystals were subjected to 3 MeV electron irradiation up to a high dose of 5.5x10{sup 18} cm{sup -2}. The production and recovery of vacancy defects were studied by positron annihilation spectroscopy. The increase of positron lifetime and Doppler broadening S parameter after irradiation indicates introduction of V {sub Zn} related defects. Most of these vacancies are annealed at temperatures below 200 {sup o}C. However, after annealing at around 400 {sup o}C, secondary defects are produced. All the vacancy defects are annealed out at around 700 {sup o}C.

  9. The Role of Hydrogen-Enhanced Strain-Induced Lattice Defects on Hydrogen Embrittlement Susceptibility of X80 Pipeline Steel

    Science.gov (United States)

    Hattori, M.; Suzuki, H.; Seko, Y.; Takai, K.

    2017-08-01

    Studies to date have not completely determined the factors influencing hydrogen embrittlement of ferrite/bainite X80 pipeline steel. Hydrogen embrittlement susceptibility was evaluated based on fracture strain in tensile testing. We conducted a thermal desorption analysis to measure the amount of tracer hydrogen corresponding to that of lattice defects. Hydrogen embrittlement susceptibility and the amount of tracer hydrogen significantly increased with decreasing crosshead speed. Additionally, a significant increase in the formation of hydrogen-enhanced strain-induced lattice defects was observed immediately before the final fracture. In contrast to hydrogen-free specimens, the fracture surface of the hydrogen-charged specimens exhibited shallower dimples without nuclei, such as secondary phase particles. These findings indicate that the presence of hydrogen enhanced the formation of lattice defects, particularly just prior to the occurrence of final fracture. This in turn enhanced the formation of shallower dimples, thereby potentially causing premature fracture of X80 pipeline steel at lower crosshead speeds.

  10. Annealing temperature effects on the magnetic properties and induced defects in C/N/O implanted MgO

    Science.gov (United States)

    Li, Qiang; Ye, Bonian; Hao, Yingping; Liu, Jiandang; Kong, Wei; Ye, Bangjiao

    2013-02-01

    Virgin MgO single crystals were implanted with 70 keV C/N/O ions at room temperature to a dose of 2 × 1017/cm2. After implantation the samples showed room temperature hysteresis in magnetization loops. The annealing effects on the magnetic properties and induced defects of these samples were determined by vibrating sample magnetometer and positron annihilation spectroscopy, respectively. The experimental results indicate that ferromagnetism can be introduced to MgO single crystals by doping with C, N or introduction of Mg related vacancy defects. However, the Mg vacancies coexistence with C or N ions in the C-/N-implanted samples may play a negative role in magnetic performance in these MgO samples. The rapid increase of magnetic moment in O-implanted sample is attributed to the formation of new type of vacancy defects.

  11. Estimating the risks of cancer mortality and genetic defects resulting from exposures to low levels of ionizing radiation

    International Nuclear Information System (INIS)

    Buhl, T.E.; Hansen, W.R.

    1984-05-01

    Estimators for calculating the risk of cancer and genetic disorders induced by exposure to ionizing radiation have been recommended by the US National Academy of Sciences Committee on the Biological Effects of Ionizing Radiations, the UN Scientific Committee on the Effects of Atomic Radiation, and the International Committee on Radiological Protection. These groups have also considered the risks of somatic effects other than cancer. The US National Council on Radiation Protection and Measurements has discussed risk estimate procedures for radiation-induced health effects. The recommendations of these national and international advisory committees are summarized and compared in this report. Based on this review, two procedures for risk estimation are presented for use in radiological assessments performed by the US Department of Energy under the National Environmental Policy Act of 1969 (NEPA). In the first procedure, age- and sex-averaged risk estimators calculated with US average demographic statistics would be used with estimates of radiation dose to calculate the projected risk of cancer and genetic disorders that would result from the operation being reviewed under NEPA. If more site-specific risk estimators are needed, and the demographic information is available, a second procedure is described that would involve direct calculation of the risk estimators using recommended risk-rate factors. The computer program REPCAL has been written to perform this calculation and is described in this report. 25 references, 16 tables

  12. Estimating the risks of cancer mortality and genetic defects resulting from exposures to low levels of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Buhl, T.E.; Hansen, W.R.

    1984-05-01

    Estimators for calculating the risk of cancer and genetic disorders induced by exposure to ionizing radiation have been recommended by the US National Academy of Sciences Committee on the Biological Effects of Ionizing Radiations, the UN Scientific Committee on the Effects of Atomic Radiation, and the International Committee on Radiological Protection. These groups have also considered the risks of somatic effects other than cancer. The US National Council on Radiation Protection and Measurements has discussed risk estimate procedures for radiation-induced health effects. The recommendations of these national and international advisory committees are summarized and compared in this report. Based on this review, two procedures for risk estimation are presented for use in radiological assessments performed by the US Department of Energy under the National Environmental Policy Act of 1969 (NEPA). In the first procedure, age- and sex-averaged risk estimators calculated with US average demographic statistics would be used with estimates of radiation dose to calculate the projected risk of cancer and genetic disorders that would result from the operation being reviewed under NEPA. If more site-specific risk estimators are needed, and the demographic information is available, a second procedure is described that would involve direct calculation of the risk estimators using recommended risk-rate factors. The computer program REPCAL has been written to perform this calculation and is described in this report. 25 references, 16 tables.

  13. A Forward Genetic Screen for Molecules Involved in Pheromone-Induced Dauer Formation in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Scott J. Neal

    2016-05-01

    Full Text Available Animals must constantly assess their surroundings and integrate sensory cues to make appropriate behavioral and developmental decisions. Pheromones produced by conspecific individuals provide critical information regarding environmental conditions. Ascaroside pheromone concentration and composition are instructive in the decision of Caenorhabditis elegans to either develop into a reproductive adult or enter into the stress-resistant alternate dauer developmental stage. Pheromones are sensed by a small set of sensory neurons, and integrated with additional environmental cues, to regulate neuroendocrine signaling and dauer formation. To identify molecules required for pheromone-induced dauer formation, we performed an unbiased forward genetic screen and identified phd (pheromone response-defective dauer mutants. Here, we describe new roles in dauer formation for previously identified neuronal molecules such as the WD40 domain protein QUI-1 and MACO-1 Macoilin, report new roles for nociceptive neurons in modulating pheromone-induced dauer formation, and identify tau tubulin kinases as new genes involved in dauer formation. Thus, phd mutants define loci required for the detection, transmission, or integration of pheromone signals in the regulation of dauer formation.

  14. NMDA Receptor Signaling Is Important for Neural Tube Formation and for Preventing Antiepileptic Drug-Induced Neural Tube Defects.

    Science.gov (United States)

    Sequerra, Eduardo B; Goyal, Raman; Castro, Patricio A; Levin, Jacqueline B; Borodinsky, Laura N

    2018-05-16

    Failure of neural tube closure leads to neural tube defects (NTDs), which can have serious neurological consequences or be lethal. Use of antiepileptic drugs (AEDs) during pregnancy increases the incidence of NTDs in offspring by unknown mechanisms. Here we show that during Xenopus laevis neural tube formation, neural plate cells exhibit spontaneous calcium dynamics that are partially mediated by glutamate signaling. We demonstrate that NMDA receptors are important for the formation of the neural tube and that the loss of their function induces an increase in neural plate cell proliferation and impairs neural cell migration, which result in NTDs. We present evidence that the AED valproic acid perturbs glutamate signaling, leading to NTDs that are rescued with varied efficacy by preventing DNA synthesis, activating NMDA receptors, or recruiting the NMDA receptor target ERK1/2. These findings may prompt mechanistic identification of AEDs that do not interfere with neural tube formation. SIGNIFICANCE STATEMENT Neural tube defects are one of the most common birth defects. Clinical investigations have determined that the use of antiepileptic drugs during pregnancy increases the incidence of these defects in the offspring by unknown mechanisms. This study discovers that glutamate signaling regulates neural plate cell proliferation and oriented migration and is necessary for neural tube formation. We demonstrate that the widely used antiepileptic drug valproic acid interferes with glutamate signaling and consequently induces neural tube defects, challenging the current hypotheses arguing that they are side effects of this antiepileptic drug that cause the increased incidence of these defects. Understanding the mechanisms of neurotransmitter signaling during neural tube formation may contribute to the identification and development of antiepileptic drugs that are safer during pregnancy. Copyright © 2018 the authors 0270-6474/18/384762-12$15.00/0.

  15. Annealing of the Sb-vacancy and a closely related radiation induced defect in n-type germanium

    Science.gov (United States)

    Barnard, Abraham W.; Auret, F. D.; Meyer, W. E.

    2018-04-01

    Deep level transient spectroscopy was used to study the defects induced by alpha-particle irradiation from an Am241 source in antimony doped n-type germanium. Previous investigations of the well know Sb-vacancy defect have led to the discovery of a second defect with very similar emission properties, referred to as the E‧. Although both defects have similar emission rates, they have very different annealing properties. In this study we further investigated these properties of the E‧ in Sb doped samples irradiated at 270 K with alpha particles from an Am241 source. Laplace deep level transient spectroscopy was used to determine the concentration of each defect. An isothermal annealing study of the E‧ was carried out in the temperature range 300 K to 325 K in 5 K increments, while the Sb-vacancy was annealed out completely at 410 K onwards, long after the E‧ was completely annealed out. The annealing activation energy was determined through isothermal annealing profiles for both the Sb-Vacancy and the E‧ as 1.05 eV and 0.73 eV respectively with a prefactor of 2.05 × 109 s-1 and 2.7 × 108 s-1.

  16. Genetic susceptibility factors for alcohol-induced chronic pancreatitis.

    Science.gov (United States)

    Aghdassi, Ali A; Weiss, F Ulrich; Mayerle, Julia; Lerch, Markus M; Simon, Peter

    2015-07-01

    Chronic pancreatitis is a progressive inflammatory disease of the pancreas and frequently associated with immoderate alcohol consumption. Since only a small proportion of alcoholics eventually develop chronic pancreatitis genetic susceptibility factors have long been suspected to contribute to the pathogenesis of the disease. Smaller studies in ethnically defined populations have found that not only polymorphism in proteins involved in the metabolism of ethanol, such as Alcohol Dehydrogenase and Aldehyde Dehydrogenase, can confer a risk for developing chronic pancreatitis but also mutations that had previously been reported in association with idiopathic pancreatitis, such as SPINK1 mutations. In a much broader approach employing genome wide search strategies the NAPS study found that polymorphisms in the Trypsin locus (PRSS1 rs10273639), and the Claudin 2 locus (CLDN2-RIPPLY1-MORC4 locus rs7057398 and rs12688220) confer an increased risk of developing alcohol-induced pancreatitis. These results from North America have now been confirmed by a European consortium. In another genome wide approach polymorphisms in the genes encoding Fucosyltransferase 2 (FUT2) non-secretor status and blood group B were not only found in association with higher serum lipase levels in healthy volunteers but also to more than double the risk for developing alcohol-associated chronic pancreatitis. These novel genetic associations will allow to investigate the pathophysiological and biochemical basis of alcohol-induced chronic pancreatitis on a cellular level and in much more detail than previously possible. Copyright © 2015 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  17. Vacancy-type defects induced by grinding of Si wafers studied by monoenergetic positron beams

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Yoshihara, Nakaaki [Division of Applied Physics, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Mizushima, Yoriko [Devices and Materials Labs Fujitsu Laboratories Ltd., Atsugi, Kanagawa 243-0197 (Japan); ICE Cube Center, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Kim, Youngsuk [ICE Cube Center, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Disco Corporation, Ota, Tokyo 143-8580 (Japan); Nakamura, Tomoji [Devices and Materials Labs Fujitsu Laboratories Ltd., Atsugi, Kanagawa 243-0197 (Japan); Ohba, Takayuki [ICE Cube Center, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Oshima, Nagayasu; Suzuki, Ryoichi [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

    2014-10-07

    Vacancy-type defects introduced by the grinding of Czochralski-grown Si wafers were studied using monoenergetic positron beams. Measurements of Doppler broadening spectra of the annihilation radiation and the lifetime spectra of positrons showed that vacancy-type defects were introduced in the surface region (<98 nm), and the major defect species were identified as (i) relatively small vacancies incorporated in dislocations and (ii) large vacancy clusters. Annealing experiments showed that the defect concentration decreased with increasing annealing temperature in the range between 100 and 500°C. After 600–700°C annealing, the defect-rich region expanded up to about 170 nm, which was attributed to rearrangements of dislocation networks, and a resultant emission of point defects toward the inside of the sample. Above 800°C, the stability limit of those vacancies was reached and they started to disappear. After the vacancies were annealed out (900°C), oxygen-related defects were the major point defects and they were located at <25 nm.

  18. Prevention of congenital defects induced by prenatal alcohol exposure (Conference Presentation)

    Science.gov (United States)

    Sheehan, Megan M.; Karunamuni, Ganga; Pedersen, Cameron J.; Gu, Shi; Doughman, Yong Qiu; Jenkins, Michael W.; Watanabe, Michiko; Rollins, Andrew M.

    2017-02-01

    Nearly 2 million women in the United States alone are at risk for an alcohol-exposed pregnancy, including more than 600,000 who binge drink. Even low levels of prenatal alcohol exposure (PAE) can lead to a variety of birth defects, including craniofacial and neurodevelopmental defects, as well as increased risk of miscarriages and stillbirths. Studies have also shown an interaction between drinking while pregnant and an increase in congenital heart defects (CHD), including atrioventricular septal defects and other malformations. We have previously established a quail model of PAE, modeling a single binge drinking episode in the third week of a woman's pregnancy. Using optical coherence tomography (OCT), we quantified intraventricular septum thickness, great vessel diameters, and atrioventricular valve volumes. Early-stage ethanol-exposed embryos had smaller cardiac cushions (valve precursors) and increased retrograde flow, while late-stage embryos presented with gross head/body defects, and exhibited smaller atrio-ventricular (AV) valves, interventricular septum, and aortic vessels. We previously showed that supplementation with the methyl donor betaine reduced gross defects, improved survival rates, and prevented cardiac defects. Here we show that these preventative effects are also observed with folate (another methyl donor) supplementation. Folate also appears to normalize retrograde flow levels which are elevated by ethanol exposure. Finally, preliminary findings have shown that glutathione, a crucial antioxidant, is noticeably effective at improving survival rates and minimizing gross defects in ethanol-exposed embryos. Current investigations will examine the impact of glutathione supplementation on PAE-related CHDs.

  19. In situ probing of the evolution of irradiation-induced defects in copper

    International Nuclear Information System (INIS)

    Li, N.; Hattar, K.; Misra, A.

    2013-01-01

    Through in situ Cu 3+ ion irradiation at room temperature in a transmission electron microscope (TEM), we have investigated the evolution of defect clusters as a function of the radiation dose at different distances from the 3 {1 1 2} incoherent twin boundary (ITB) in Cu. Post in situ ion irradiation, high resolution TEM was used to explore the types of defects, which are composed of a high-density of vacancy stacking fault tetrahedra (SFT) and sparsely distributed interstitial Frank loops. During irradiation, defect clusters evolve through four stages: (i) incubation, (ii) non-interaction, (iii) interaction and (iv) saturation; and the corresponding density was observed to initially increase with irradiation dose and then approach saturation. No obvious denuded zone is observed along the 3 {1 1 2} ITB and the configuration of defects at the boundary displays as truncated SFTs. Several defect evolution models have been proposed to explain the observed phenomena

  20. Echo detected EPR as a tool for detecting radiation-induced defect signals in pottery

    International Nuclear Information System (INIS)

    Zoleo, Alfonso; Bortolussi, Claudia; Brustolon, Marina

    2011-01-01

    Archaeological fragments of pottery have been investigated by using CW-EPR and Echo Detected EPR (EDEPR). EDEPR allows to remove the CW-EPR dominant Fe(III) background spectrum, hiding much weaker signals potentially useful for dating purpose. EDEPR spectra attributed to a methyl radical and to feldspar defects have been recorded at room and low temperature for an Iron Age cooking ware (700 B.C.). A study on the dependence of EDEPR intensity over absorbed dose on a series of γ-irradiated brick samples (estimated age of 562 ± 140 B.C.) has confirmed the potential efficacy of the proposed method for spotting defect signals out of the strong iron background. - Highlights: → Fe(III) CW-EPR signals cover CW-EPR-detectable defects in ceramics. → Echo detected EPR gets rid of Fe(III) signals, disclosing defect signals. → Echo detected EPR detects defect signals even at relatively low doses.

  1. Curvature-induced defect unbinding and dynamics in active nematic toroids

    Science.gov (United States)

    Ellis, Perry W.; Pearce, Daniel J. G.; Chang, Ya-Wen; Goldsztein, Guillermo; Giomi, Luca; Fernandez-Nieves, Alberto

    2018-01-01

    Nematic order on curved surfaces is often disrupted by the presence of topological defects, which are singular regions in which the orientational order is undefined. In the presence of force-generating active materials, these defects are able to migrate through space like swimming microorganisms. We use toroidal surfaces to show that despite their highly chaotic and non-equilibrium dynamics, pairs of defects unbind and segregate in regions of opposite Gaussian curvature. Using numerical simulations, we find that the degree of defect unbinding can be controlled by tuning the system activity, and even suppressed in strongly active systems. Furthermore, by using the defects as active microrheological tracers and quantitatively comparing our experimental and theoretical results, we are able to determine material properties of the active nematic. Our results illustrate how topology and geometry can be used to control the behaviour of active materials, and introduce a new avenue for the quantitative mechanical characterization of active fluids.

  2. Low-dose ionizing radiation alleviates Aβ42-induced defective phenotypes in Drosophila Alzheimer's disease models

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, SooJin; Jeong, Hae Min; Nam, Seon Young [Low-dose Radiation Research Team, Radiation Health Institute, Korea Hydro & Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)

    2017-04-15

    Alzheimer's disease (AD) is the most common neurodegenerative disease that is characterized by amyloid plaques, progressive neuronal loss, and gradual deterioration of memory. Amyloid imaging using positron emission tomography (PET) radiotracers have been developed and approved for clinical use in the evaluation of suspected neurodegenerative disease, including AD. Particularly, previous studies involving low-dose ionizing radiation on Aβ 42-treated mouse hippocampal neurons have suggested a potential role for low-dose ionizing radiation in the treatment of AD. However, associated in vivo studies involving the therapy effects of low-dose ionizing radiation on AD are still insufficient. As a powerful cell biological system, Drosophila AD models have been generated and established a useful model organism for study on the etiology of human AD. In this study, we investigated the hormesis effects of low-dose ionizing radiation on Drosophila AD models. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation.

  3. Use of porous silicon to minimize oxidation induced stacking fault defects in silicon

    International Nuclear Information System (INIS)

    Shieh, S.Y.; Evans, J.W.

    1992-01-01

    This paper presents methods for minimizing stacking fault defects, generated during oxidation of silicon, include damaging the back of the wafer or depositing poly-silicon on the back. In either case a highly defective structure is created and this is capable of gettering either self-interstitials or impurities which promote nucleation of stacking fault defects. A novel method of minimizing these defects is to form a patch of porous silicon on the back of the wafer by electrochemical etching. Annealing under inert gas prior to oxidation may then result in the necessary gettering. Experiments were carried out in which wafers were subjected to this treatment. Subsequent to oxidation, the wafers were etched to remove oxide and reveal defects. The regions of the wafer adjacent to the porous silicon patch were defect-free, whereas remote regions had defects. Deep level transient spectroscopy has been used to examine the gettering capability of porous silicon, and the paper discusses the mechanism by which the porous silicon getters

  4. Alcohol-induced defects in hepatic transcytosis may be explained by impaired dynein function.

    Science.gov (United States)

    Groebner, Jennifer L; Fernandez, David J; Tuma, Dean J; Tuma, Pamela L

    2014-12-01

    Alcoholic liver disease has been clinically well described, but the molecular mechanisms leading to hepatotoxicity have not been fully elucidated. Previously, we determined that microtubules are hyperacetylated and more stable in ethanol-treated WIF-B cells, VL-17A cells, liver slices, and in livers from ethanol-fed rats. From our recent studies, we believe that these modifications can explain alcohol-induced defects in microtubule motor-dependent protein trafficking including nuclear translocation of a subset of transcription factors. Since cytoplasmic dynein/dynactin is known to mediate both microtubule-dependent translocation and basolateral to apical/canalicular transcytosis, we predicted that transcytosis is impaired in ethanol-treated hepatic cells. We monitored transcytosis of three classes of newly synthesized canalicular proteins in polarized, hepatic WIF-B cells, an emerging model system for the study of liver disease. As predicted, canalicular delivery of all proteins tested was impaired in ethanol-treated cells. Unlike in control cells, transcytosing proteins were observed in discrete sub-canalicular puncta en route to the canalicular surface that aligned along acetylated microtubules. We further determined that the stalled transcytosing proteins colocalized with dynein/dynactin in treated cells. No changes in vesicle association were observed for either dynein or dynactin in ethanol-treated cells, but significantly enhanced dynein binding to microtubules was observed. From these results, we propose that enhanced dynein binding to microtubules in ethanol-treated cells leads to decreased motor processivity resulting in vesicle stalling and in impaired canalicular delivery. Our studies also importantly indicate that modulating cellular acetylation levels with clinically tolerated deacetylase agonists may be a novel therapeutic strategy for treating alcoholic liver disease.

  5. Influence of the formation- and passivation rate of boron-oxygen defects for mitigating carrier-induced degradation in silicon within a hydrogen-based model

    International Nuclear Information System (INIS)

    Hallam, Brett; Abbott, Malcolm; Nampalli, Nitin; Hamer, Phill; Wenham, Stuart

    2016-01-01

    A three-state model is used to explore the influence of defect formation- and passivation rates of carrier-induced degradation related to boron-oxygen complexes in boron-doped p-type silicon solar cells within a hydrogen-based model. The model highlights that the inability to effectively mitigate carrier-induced degradation at elevated temperatures in previous studies is due to the limited availability of defects for hydrogen passivation, rather than being limited by the defect passivation rate. An acceleration of the defect formation rate is also observed to increase both the effectiveness and speed of carrier-induced degradation mitigation, whereas increases in the passivation rate do not lead to a substantial acceleration of the hydrogen passivation process. For high-throughput mitigation of such carrier-induced degradation on finished solar cell devices, two key factors were found to be required, high-injection conditions (such as by using high intensity illumination) to enable an acceleration of defect formation whilst simultaneously enabling a rapid passivation of the formed defects, and a high temperature to accelerate both defect formation and defect passivation whilst still ensuring an effective mitigation of carrier-induced degradation

  6. Observation of zone folding induced acoustic topological insulators and the role of spin-mixing defects

    Science.gov (United States)

    Deng, Yuanchen; Ge, Hao; Tian, Yuan; Lu, Minghui; Jing, Yun

    2017-11-01

    This article reports on the experimental realization of a flow-free, pseudospin-based acoustic topological insulator designed using the strategy of zone folding. Robust sound one-way propagation is demonstrated with the presence of non-spin-mixing defects. On the other hand, it is shown that spin-mixing defects, which break the geometric symmetry and therefore the pseudo-time-reversal symmetry, can open up nontrivial band gaps within the edge state frequency band, and their width can be tailored by the extent of the defect. This provides a possible route for realizing tunable acoustic topological insulators.

  7. Surface-defect induced modifications in the optical properties of α-MnO{sub 2} nanorods

    Energy Technology Data Exchange (ETDEWEB)

    John, Reenu Elizabeth [Department of Physics, St. Berchmans College, Changanassery, Kerala 686101 (India); Chandran, Anoop [School of Pure and Applied Physics, MG University, Kottayam, Kerala 686560 (India); Thomas, Marykutty [Department of Physics, BCM College, Kottayam, Kerala 686001 (India); Jose, Joshy [Department of Physics, St. Berchmans College, Changanassery, Kerala 686101 (India); George, K.C., E-mail: drkcgeorge@gmail.com [Department of Physics, St. Berchmans College, Changanassery, Kerala 686101 (India)

    2016-03-30

    Graphical abstract: - Highlights: • Alpha-MnO{sub 2} nanorods are prepared by chemical method. • Difference in surface defect density is achieved. • Characterized using XRD, Rietveld, XPS, EDS, HR-TEM, BET, UV–vis absorption spectroscopy and PL spectroscopy. • Explains the bandstructure modification due to Jahn–Teller distortions using crystal field theory. • Modification in the intensity of optical emissions related to defect levels validates the concept of surface defect induced tuning of optical properties. - Abstract: The science of defect engineering via surface tuning opens a new route to modify the inherent properties of nanomaterials for advanced functional and practical applications. In this work, two independent synthesis methods (hydrothermal and co-precipitation) are adopted to fabricate α-MnO{sub 2} nanorods with different defect structures so as to understand the effect of surface modifications on their optical properties. The crystal structure and morphology of samples are investigated with the aid of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Atomic composition calculated from energy dispersive spectroscopy (EDS) confirms non-stoichiometry of the samples. The surface properties and chemical environment are thoroughly studied using X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) analysis. Bond angle variance and bond valence sum are determined to validate distortions in the basic MnO{sub 6} octahedron. The surface studies indicate that the concentration of Jahn–Teller manganese (III) (Mn{sup 3+}) ion in the samples differ from each other which results in their distinct properties. Band structure modifications due to Jahn–Teller distortion are examined with the aid of ultraviolet–visible (UV) reflectance and photoluminescence (PL) studies. The dual peaks obtained in derivative spectrum conflict the current concept on the bandgap energy of MnO{sub 2}. These

  8. The evolution of interaction between grain boundary and irradiation-induced point defects: Symmetric tilt GB in tungsten

    Science.gov (United States)

    Li, Hong; Qin, Yuan; Yang, Yingying; Yao, Man; Wang, Xudong; Xu, Haixuan; Phillpot, Simon R.

    2018-03-01

    Molecular dynamics method is used and scheme of calculational tests is designed. The atomic evolution view of the interaction between grain boundary (GB) and irradiation-induced point defects is given in six symmetric tilt GB structures of bcc tungsten with the energy of the primary knock-on atom (PKA) EPKA of 3 and 5 keV and the simulated temperature of 300 K. During the collision cascade with GB structure there are synergistic mechanisms to reduce the number of point defects: one is vacancies recombine with interstitials, and another is interstitials diffuse towards the GB with vacancies almost not move. The larger the ratio of the peak defect zone of the cascades overlaps with the GB region, the statistically relative smaller the number of surviving point defects in the grain interior (GI); and when the two almost do not overlap, vacancy-intensive area generally exists nearby GBs, and has a tendency to move toward GB with the increase of EPKA. In contrast, the distribution of interstitials is relatively uniform nearby GBs and is affected by the EPKA far less than the vacancy. The GB has a bias-absorption effect on the interstitials compared with vacancies. It shows that the number of surviving vacancies statistically has increasing trend with the increase of the distance between PKA and GB. While the number of surviving interstitials does not change much, and is less than the number of interstitials in the single crystal at the same conditions. The number of surviving vacancies in the GI is always larger than that of interstitials. The GB local extension after irradiation is observed for which the interstitials absorbed by the GB may be responsible. The designed scheme of calculational tests in the paper is completely applicable to the investigation of the interaction between other types of GBs and irradiation-induced point defects.

  9. Precipitation of ferromagnetic phase induced by defect energies during creep deformation in Type 304 austenitic steel

    International Nuclear Information System (INIS)

    Tsukada, Yuhki; Shiraki, Atsuhiro; Murata, Yoshinori; Takaya, Shigeru; Koyama, Toshiyuki; Morinaga, Masahiko

    2010-01-01

    The correlation of defect energies with precipitation of the ferromagnetic phase near M 23 C 6 carbide during creep tests at high temperature in Type 304 austenitic steel was examined by estimating the defect energies near the carbide, based on micromechanics. As one of the defect energies, the precipitation energy was calculated by assuming M 23 C 6 carbide to be a spherical inclusion. The other defect energy, creep dislocation energy, was calculated based on dislocation density data obtained from transmission electron microscopy observations of the creep samples. The dislocation energy density was much higher than the precipitation energy density in the initial stage of the creep process, when the ferromagnetic phase started to increase. Creep dislocation energy could be the main driving force for precipitation of the ferromagnetic phase.

  10. Precipitation of ferromagnetic phase induced by defect energies during creep deformation in Type 304 austenitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, Yuhki, E-mail: tsukada@silky.numse.nagoya-u.ac.j [Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Shiraki, Atsuhiro; Murata, Yoshinori [Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Takaya, Shigeru [Japan Atomic Energy Agency, 4002 Narita-cho, O-arai-machi, Higashi-ibaraki-gun, Ibaraki 311-1393 (Japan); Koyama, Toshiyuki [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Morinaga, Masahiko [Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2010-06-15

    The correlation of defect energies with precipitation of the ferromagnetic phase near M{sub 23}C{sub 6} carbide during creep tests at high temperature in Type 304 austenitic steel was examined by estimating the defect energies near the carbide, based on micromechanics. As one of the defect energies, the precipitation energy was calculated by assuming M{sub 23}C{sub 6} carbide to be a spherical inclusion. The other defect energy, creep dislocation energy, was calculated based on dislocation density data obtained from transmission electron microscopy observations of the creep samples. The dislocation energy density was much higher than the precipitation energy density in the initial stage of the creep process, when the ferromagnetic phase started to increase. Creep dislocation energy could be the main driving force for precipitation of the ferromagnetic phase.

  11. Temperature dependence of radiation induced defect creation in a-SiO2

    International Nuclear Information System (INIS)

    Devine, R.A.B.; Grouillet, A.; Berlivet, J.Y.

    1988-01-01

    The efficiency of oxygen vacancy defect creation in samples of amorphous SiO 2 subjected to ultraviolet laser or ionizing particle radiation (energetic H + ions) has been measured as a function of sample temperature during irradiation. For the case of laser radiation (E photon ≅ 5 eV) we find that vacancy centers are only created when the irradiation temperature is above 150 K. The efficiency of peroxy radical defect creation observed after post irradiation annealing is consistent with the behaviour of the oxygen vacancy creation efficiency. In samples with energetic protons, the opposite behaviour is observed and one finds that defect creation is enhanced as the implantation temperature is lowered. Possible physical mechanisms controlling the defect creation efficiency as a function of sample temperature and radiation are discussed. (orig.)

  12. Deformation behaviour induced by point defects near a Cu(0 0 1) surface

    International Nuclear Information System (INIS)

    Said-Ettaoussi, M.; Jimenez-Saez, J.C.; Perez-Martin, A.M.C.; Jimenez-Rodriguez, J.J.

    2004-01-01

    In order to attain a satisfactory understanding of many of the properties of metallic surfaces, it is necessary to take into account the distorting effect of self-interstitials and vacancies. The present work is focused on the study of the behaviour of neighbouring atoms around point defects. The conjugate gradient method with an empiric many-body potential has been used to study the point defect-surface interaction. Point defects have been generated at several depths under a Cu(0 0 1) surface and then the whole system driven to the minimum energy state. The displacement field has been obtained in the vicinity to the defect. An energetic analysis is also carried out calculating formation and migration energies

  13. Unexpected properties of the inductively coupled plasma induced defect in germanium

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, S.M.M., E-mail: sergio@up.ac.za; Auret, F.D.; Janse van Rensburg, P.J.; Nel, J.M.

    2014-04-15

    Inductively coupled plasma (ICP) etching of germanium introduces a single defect, the E{sub 0.31} electron trap, for a large range of argon partial pressures from 4×10{sup –3} to 6.5×10{sup –4} mbar that correspond to ion energies of 8 to 60 eV. Ge of three crystallographic orientations, (1 0 0), (1 1 0) and (1 1 1), treated with 20 and 60 eV ICP had defect concentration profiles that were similar in appearance, with a maximum concentration of 10{sup 14} cm{sup −3} extending more than a µm into the material, approximately three orders of magnitude deeper than what TRIM simulations predicted. All profiles were measured using Laplace deep level transient spectroscopy (L-DLTS), a technique that is sensitive to defect concentrations as low as 10{sup 11} cm{sup −3}. Isochronal annealing of samples showed concentration curves broadening after a 400 K anneal and decreasing to the 10{sup 13} cm{sup −3} level after a 450 K anneal. Unannealed samples measured after a year exhibited similar decreases in defect concentration without broadening of their profiles. A 550 K anneal lowered the defect concentration to levels below the L-DLTS detection limit. Thereafter additional plasma treatment of the surface failed to reintroduce this defect indicating that the structure required for the formation of E{sub 0.31} was no longer present in the region under observation.

  14. Nickel sulfate induces numerous defects in Caenorhabditis elegans that can also be transferred to progeny

    International Nuclear Information System (INIS)

    Wang Dayong; Wang Yang

    2008-01-01

    Whether the multiple biological toxicities from nickel exposure could be transferred to progeny has not been clarified. In this report, we explored the Caenorhabditis elegans to analyze the multiple toxicities of nickel and their possibly transferable properties. The nickel toxicity caused multiple biological defects in a concentration-dependent manner. Moreover, most of these toxicities could be transferred and could be only partially rescued in progeny. Some specific phenotypes in progeny were also found to exhibit no obvious rescue phenotypes or to show even more severe defects than their parents. The defects caused by nickel exposure could be classified into four groups according to their transferring properties. That is, the defects caused by nickel exposure could be largely, or partially, or unable to be rescued, or became even more severe in progeny animals. Therefore, most of the nickel exposure-caused defects can be transferred from parents to their progeny to different degrees in C. elegans. - Nickel exposure can cause multi-biological toxicities and these defects can be transferred from parents to their progeny in C. elegans

  15. Nickel sulfate induces numerous defects in Caenorhabditis elegans that can also be transferred to progeny

    Energy Technology Data Exchange (ETDEWEB)

    Wang Dayong [Department of Genetics and Developmental Biology, Southeast University, Nanjing 210009 (China); Key Laboratory of Developmental Genes and Human Disease, Ministry of Education (China)], E-mail: dayongw@seu.edu.cn; Wang Yang [Department of Genetics and Developmental Biology, Southeast University, Nanjing 210009 (China); Key Laboratory of Developmental Genes and Human Disease, Ministry of Education (China)

    2008-02-15

    Whether the multiple biological toxicities from nickel exposure could be transferred to progeny has not been clarified. In this report, we explored the Caenorhabditis elegans to analyze the multiple toxicities of nickel and their possibly transferable properties. The nickel toxicity caused multiple biological defects in a concentration-dependent manner. Moreover, most of these toxicities could be transferred and could be only partially rescued in progeny. Some specific phenotypes in progeny were also found to exhibit no obvious rescue phenotypes or to show even more severe defects than their parents. The defects caused by nickel exposure could be classified into four groups according to their transferring properties. That is, the defects caused by nickel exposure could be largely, or partially, or unable to be rescued, or became even more severe in progeny animals. Therefore, most of the nickel exposure-caused defects can be transferred from parents to their progeny to different degrees in C. elegans. - Nickel exposure can cause multi-biological toxicities and these defects can be transferred from parents to their progeny in C. elegans.

  16. Induced membrane technique combined with two-stage internal fixation for the treatment of tibial osteomyelitis defects.

    Science.gov (United States)

    Luo, Fei; Wang, Xiaohua; Wang, Shulin; Fu, Jingshu; Xie, Zhao

    2017-07-01

    The purpose of this study was to observe the effects of induced membrane technique combined with two-stage internal fixation in the treatment of tibial osteomyelitis defects. A retrospective analyses for 67 cases of tibialosteomyelitis defects were admitted to our department between September 2012 to February 2015, which were treated with induced membrane technique. At the first stage, implanted with a PMMA cement spacer in the defects after radical debridement and fixed with reconstructive locked plate. Bone grafting and exchanged the plate with intramedullary nail at the second stage. In current study, all patients were followed up for 18-35 months. Sixty-six patients achieved bone union with the average radiographic and clinical healing times of 5.55±2.19 and 7.45±1.69months, respectively. Seven patients required a second debridement before grafting, while four patients experienced a recurrence of infection or a relapse following second stage treatment. Twelve patients experienced either knee or ankle dysfunctions and 2 patients faced delayed wound healing. Donor site complications includes pain and infection were found in 7 and 3 patients, respectively with delayed stress fracture in 1 patient only. Induced membrane technique for the treatment of tibial osteomyelitis defects, seems a reliable method. The use of reconstructive locked plate as a temporary internal fixation at the first stage and exchanged with intramedullary nail at the second stage, potentially achieves good clinical efficacy. Care should be taken to restore the joint function especially in distal tibia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Defect generation and activation processes in HfO{sub 2} thin films: Contributions to stress-induced leakage currents

    Energy Technology Data Exchange (ETDEWEB)

    Oettking, Rolf; Leitsmann, Roman; Lazarevic, Florian; Plaenitz, Philipp [AQcomputare, Business Unit MATcalc, Chemnitz (Germany); Kupke, Steve; Roll, Guntrade; Slesazeck, Stefan [NaMLab gGmbH, Dresden (Germany); Nadimi, Ebrahim [AQcomputare, Business Unit MATcalc, Chemnitz (Germany); K.N. Toosi University of Technology, Faculty of Electrical Engineering, Tehran (Iran, Islamic Republic of); Trentzsch, Martin [Globalfoundries Dresden, Dresden (Germany); Mikolajick, Thomas [Technische Universitaet Dresden, Fakultaet Elektrotechnik und Informationstechnik, Institut fuer Halbleiter- und Mikrosystemtechnik, Dresden (Germany)

    2015-03-01

    An important source of degradation in thin dielectric material layers is the generation and migration of oxygen vacancies. We investigated the formation of Frenkel pairs (FPs) in HfO{sub 2} as the first structural step for the creation of new defects as well as the migration of preexisting and newly built oxygen vacancies by nudged elastic band (NEB) calculations and stress induced leakage current (SILC) experiments. The analysis indicates, that for neutral systems no stable intimate FPs are built, whereas for the charge states q = ± 2 FPs are formed at threefold and at fourfold coordinated oxygen lattice sites. Their generation and annihilation rate are in equilibrium according to the Boltzmann statistics. Distant FPs (stable defects) are unlikely to build due to high formation energies and therefore cannot be accounted for the measured gate leakage current increase of nMOSFETs under constant voltage stress. The negatively charged oxygen vacancies were found to be very immobile in contrast to positively charged V{sub 0}'s with a low migration barrier that coincides well with the experimentally obtained activation energy. We show that rather the activation of preexisting defects and migration towards the interface than the defect generation are the cause for the gate oxide degradation. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Dark current spectroscopy of space and nuclear environment induced displacement damage defects in pinned photodiode based CMOS image sensors

    International Nuclear Information System (INIS)

    Belloir, Jean-Marc

    2016-01-01

    CMOS image sensors are envisioned for an increasing number of high-end scientific imaging applications such as space imaging or nuclear experiments. Indeed, the performance of high-end CMOS image sensors has dramatically increased in the past years thanks to the unceasing improvements of microelectronics, and these image sensors have substantial advantages over CCDs which make them great candidates to replace CCDs in future space missions. However, in space and nuclear environments, CMOS image sensors must face harsh radiation which can rapidly degrade their electro-optical performances. In particular, the protons, electrons and ions travelling in space or the fusion neutrons from nuclear experiments can displace silicon atoms in the pixels and break the crystalline structure. These displacement damage effects lead to the formation of stable defects and to the introduction of states in the forbidden bandgap of silicon, which can allow the thermal generation of electron-hole pairs. Consequently, non ionizing radiation leads to a permanent increase of the dark current of the pixels and thus a decrease of the image sensor sensitivity and dynamic range. The aim of the present work is to extend the understanding of the effect of displacement damage on the dark current increase of CMOS image sensors. In particular, this work focuses on the shape of the dark current distribution depending on the particle type, energy and fluence but also on the image sensor physical parameters. Thanks to the many conditions tested, an empirical model for the prediction of the dark current distribution induced by displacement damage in nuclear or space environments is experimentally validated and physically justified. Another central part of this work consists in using the dark current spectroscopy technique for the first time on irradiated CMOS image sensors to detect and characterize radiation-induced silicon bulk defects. Many types of defects are detected and two of them are identified

  19. Prevention of congenital defects induced by prenatal alcohol exposure (Conference Presentation)

    Science.gov (United States)

    Sheehan, Megan M.; Karunamuni, Ganga; Pedersen, Cameron J.; Gu, Shi; Doughman, Yong Qiu; Jenkins, Michael W.; Watanabe, Michiko; Rollins, Andrew M.

    2017-02-01

    Over 500,000 women per year in the United States drink during pregnancy, and 1 in 5 of this population also binge drink. Up to 40% of live-born children with prenatal alcohol exposure (PAE) present with congenital heart defects (CHDs) including life-threatening outflow and valvuloseptal anomalies. Previously we established a PAE model in the avian embryo and used optical coherence tomography (OCT) imaging to assay looping-stage (early) cardiac function/structure and septation-stage (late) cardiac defects. Early-stage ethanol-exposed embryos had smaller cardiac cushions (valve precursors) and increased retrograde flow, while late-stage embryos presented with gross head/body defects, and exhibited smaller atrio-ventricular (AV) valves, interventricular septae, and aortic vessels. However, supplementation with the methyl donor betaine reduced gross defects, prevented cardiac defects such as ventricular septal defects and abnormal AV valves, and normalized cardiac parameters. Immunofluorescent staining for 5-methylcytosine in transverse embryo sections also revealed that DNA methylation levels were reduced by ethanol but normalized by co-administration of betaine. Furthermore, supplementation with folate, another methyl donor, in the PAE model appeared to normalize retrograde flow levels which are typically elevated by ethanol exposure. Studies are underway to correlate retrograde flow numbers for folate with associated cushion volumes. Finally, preliminary findings have revealed that glutathione, a key endogenous antioxidant which also regulates methyl group donation, is particularly effective in improving alcohol-impacted survival and gross defect rates. Current investigations will determine whether glutathione has any positive effect on PAE-related CHDs. Our studies could have significant implications for public health, especially related to prenatal nutrition recommendations.

  20. Genetics Home Reference: X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection, and neoplasia

    Science.gov (United States)

    ... Conditions XMEN X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection, and neoplasia Printable PDF Open All Close ... boxes. Description X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection, and neoplasia (typically known by the acronym ...

  1. Generation and genetic modification of induced pluripotent stem cells.

    Science.gov (United States)

    Schambach, Axel; Cantz, Tobias; Baum, Christopher; Cathomen, Toni

    2010-07-01

    The generation of induced pluripotent stem cells (iPSCs) enabled by exogenous expression of the canonical Oct4, Sox2, Klf4 and c-Myc reprogramming factors has opened new ways to create patient- or disease-specific pluripotent cells. iPSCs represent an almost inexhaustible source of cells for targeted differentiation into somatic effector cells and hence are likely to be invaluable for therapeutic applications and disease-related research. After an introduction on the biology of reprogramming we cover emerging technological advances, including new reprogramming approaches, small-molecule compounds and tailored genetic modification, and give an outlook towards potential clinical applications of iPSCs. Although this field is progressing rapidly, reprogramming is still an inefficient process. The reader will learn about innovative tools to generate patient-specific iPSCs and how to modify these established lines in a safe way. Ideally, the disease-causing mutation is edited directly in the genome using novel technologies based on artificial nucleases, such as zinc-finger nucleases. Human iPSCs create fascinating options with regard to disease modeling, drug testing, developmental studies and therapeutic applications. However, important hurdles have to be taken and more efficient protocols to be established to achieve the ambitious goal of bringing iPSCs into clinical use.

  2. The effects of photobiomodulation on healing of bone defects in streptozotocin induced diabetic rats

    Science.gov (United States)

    Martinez Costa Lino, Maíra D.; Bastos de Carvalho, Fabíola; Ferreira Moraes, Michel; Augusto Cardoso, José; Pinheiro, Antônio L. B.; Maria Pedreira Ramalho, Luciana

    2011-03-01

    Previous studies have shown positive effects of Low level laser therapy (LLLT) on the repair of bone defects, but there are only a few that associates bone healing in the presence of a metabolic disorder as Diabetes Melitus and LLLT. The aim of this study was to assess histologically the effect of LLLT (AsGaAl), 780nm, 70mW, CW, Ø~0.4mm, 16J/cm2 per session) on the repair of surgical defects created in the femur of diabetic and non-diabetic Wistar Albinus rats. Surgical bone defects were created in 60 animals divided into four groups of 15 animals each: Group C (non-diabetic - control); Group CL (non-diabetic + LLLT); Group CD (diabetic); Group CDL (diabetic + LLLT). The animals on the irradiated group received 16 J/cm2 per session divided into four points around the defect, being the first irradiation immediately after surgery and repeated every 48h for 14 days. The animals were killed 15, 21 and 30 days after surgery. The results of the present investigation showed histological evidence of improved amount of collagen fibers at early stages of the bone healing (15 days) and increased amount of well organized bone trabeculae at the end of the experimental period (30 days) on irradiated animals, (diabetic and non-diabetic) compared to non irradiated ones. It is concluded that LLLT has a positive biomodulative effect on the healing process of bone defects, even when diabetes mellitus was present.

  3. Time and temperature dependence of cascade induced defect production in in situ experiments and computer simulation

    International Nuclear Information System (INIS)

    Ishino, Shiori

    1993-01-01

    Understanding of the defect production and annihilation processes in a cascade is important in modelling of radiation damage for establishing irradiation correlation. In situ observation of heavy ion radiation damage has a great prospect in this respect. Time and temperature dependence of formation and annihilation of vacancy clusters in a cascade with a time resolution of 30 ms has been studied with a facility which comprises a heavy ion accelerator and an electron microscope. Formation and annihilation rates of defect clusters have been separately measured by this technique. The observed processes have been analysed by simple kinetic equations, taking into account the sink effect of surface and the defect clusters themselves together with the annihilation process due to thermal emission of vacancies from the defect clusters. Another tool to study time and temperature dependence of defect production in a cascade is computer simulation. Recent results of molecular dynamics calculations on the temperature dependence of cascade evolution are presented, including directional and temperature dependence of the lengths of replacement collision sequences, temperature dependence of the process to reach thermal equilibrium and so on. These results are discussed under general time frame of radiation damage evolution covering from 10 -15 to 10 9 s, and several important issues for the general understanding have been identified. (orig.)

  4. Self-fitting shape memory polymer foam inducing bone regeneration: A rabbit femoral defect study.

    Science.gov (United States)

    Xie, Ruiqi; Hu, Jinlian; Hoffmann, Oskar; Zhang, Yuanchi; Ng, Frankie; Qin, Tingwu; Guo, Xia

    2018-04-01

    Although tissue engineering has been attracted greatly for healing of critical-sized bone defects, great efforts for improvement are still being made in scaffold design. In particular, bone regeneration would be enhanced if a scaffold precisely matches the contour of bone defects, especially if it could be implanted into the human body conveniently and safely. In this study, polyurethane/hydroxyapatite-based shape memory polymer (SMP) foam was fabricated as a scaffold substrate to facilitate bone regeneration. The minimally invasive delivery and the self-fitting behavior of the SMP foam were systematically evaluated to demonstrate its feasibility in the treatment of bone defects in vivo. Results showed that the SMP foam could be conveniently implanted into bone defects with a compact shape. Subsequently, it self-matched the boundary of bone defects upon shape-recovery activation in vivo. Micro-computed tomography determined that bone ingrowth initiated at the periphery of the SMP foam with a constant decrease towards the inside. Successful vascularization and bone remodeling were also demonstrated by histological analysis. Thus, our results indicate that the SMP foam demonstrated great potential for bone regeneration. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Defect-induced Au precipitation in Fe–Au and Fe–Au–B–N alloys studied by in situ small-angle neutron scattering

    International Nuclear Information System (INIS)

    Zhang, S.; Kohlbrecher, J.; Tichelaar, F.D.; Langelaan, G.; Brück, E.; Zwaag, S. van der; Dijk, N.H. van

    2013-01-01

    Nanoscale Au precipitation in high-purity Fe–Au and Fe–Au–B–N alloys has been studied by in situ small-angle neutron scattering during isothermal aging at 550 °C and complementary ex situ transmission electron microscopy. The high temperature precipitation behavior in samples having received different degrees of cold deformation has been studied to explore the potential self-healing of deformation-induced defects by Au precipitation. It is found that dislocations induced by prior plastic deformation strongly facilitate the formation of Au precipitates, as no significant precipitation is observed for undeformed samples. Defect-induced Au precipitates are formed both at dislocations and along grain boundaries where the defect density is high. The fact that the Au atoms only precipitate on deformation-induced defects demonstrates that solute gold atoms act as efficient self-healing agents in the ferrous matrix. The addition of B and N is found to retard the Au precipitation

  6. Turmeric Extract Rescues Ethanol-Induced Developmental Defect in the Zebrafish Model for Fetal Alcohol Spectrum Disorder (FASD).

    Science.gov (United States)

    Muralidharan, Pooja; Connors, Craig T; Mohammed, Arooj S; Sarmah, Swapnalee; Marrs, Kathleen; Marrs, James A; Chism, Grady W

    2017-09-01

    Prenatal ethanol exposure causes the most frequent preventable birth disorder, fetal alcohol spectrum disorder (FASD). The effect of turmeric extracts in rescuing an ethanol-induced developmental defect using zebrafish as a model was determined. Ethanol-induced oxidative stress is one of the major mechanisms underlying FASD. We hypothesize that antioxidant inducing properties of turmeric may alleviate ethanol-induced defects. Curcuminoid content of the turmeric powder extract (5 mg/mL turmeric in ethanol) was determined by UPLC and found to contain Curcumin (124.1 ± 0.2 μg/mL), Desmethoxycurcumin (43.4 ± 0.1 μg/mL), and Bisdemethoxycurcumin (36.6 ± 0.1 μg/mL). Zebrafish embryos were treated with 100 mM (0.6% v/v) ethanol during gastrulation through organogenesis (2 to 48 h postfertilization (hpf)) and supplemented with turmeric extract to obtain total curcuminoid concentrations of 0, 1.16, 1.72, or 2.32 μM. Turmeric supplementation showed significant rescue of the body length at 72 hpf compared to ethanol-treated embryos. The mechanism underlying the rescue remains to be determined. © 2017 Institute of Food Technologists®.

  7. Radiation-induced defect production in MgF2-Co crystals

    International Nuclear Information System (INIS)

    Nuritdinov, I.; Turdanov, K.; Mirinoyatova, N.M.; Rejterov, V.M.

    1996-01-01

    Impact of Co-admixture on structural radiation defects formation in the MgF 2 crystals is studied. It is found that the Co admixture facilitates the probability of generating the F- and m-type centers of radiation defects as well as creation of the F- and M-centers, perturbed by admixtures. The availability of structural defects leads in its turn to the admixture ions perturbation. It is reflected in the removal of prohibition on spin-prohibited transitions of the Co 2 + ions. It is assumed that creation of the M-centers is the main cause for removal of the prohibition on the spin-prohibited transitions. 8 refs., 4 figs

  8. Analysis of Manufacturing-Induced Defects and Structural Deformations in Lithium-Ion Batteries Using Computed Tomography

    Directory of Open Access Journals (Sweden)

    Yi Wu

    2018-04-01

    Full Text Available Premature battery drain, swelling and fires/explosions in lithium-ion batteries have caused wide-scale customer concerns, product recalls, and huge financial losses in a wide range of products including smartphones, laptops, e-cigarettes, hoverboards, cars, and commercial aircraft. Most of these problems are caused by defects which are difficult to detect using conventional nondestructive electrical methods and disassembly-based destructive analysis. This paper develops an effective computed tomography (CT-based nondestructive approach to assess battery quality and identify manufacturing-induced defects and structural deformations in batteries. Several unique case studies from commercial e-cigarette and smartphone applications are presented to show where CT analysis methods work.

  9. Defect-induced luminescence in sol-gel silica samples doped with Co(II) at different concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Sandoval, S. [Centro de Investigacion y Estudios Avanzados, Queretaro, Apdo. Postal 1-798, Queretaro, Qro. 76001 (Mexico); Estevez, M. [Fisica Aplicada y Tecnologia Avanzada, UNAM, Apdo. Postal 1-1010, Queretaro, Qro. 76000 (Mexico); Pacheco, S. [Instituto Mexicano del Petroleo, Av. 100 metros (Mexico); Vargas, S. [Fisica Aplicada y Tecnologia Avanzada, UNAM, Apdo. Postal 1-1010, Queretaro, Qro. 76000 (Mexico); Rodriguez, R. [Fisica Aplicada y Tecnologia Avanzada, UNAM, Apdo. Postal 1-1010, Queretaro, Qro. 76000 (Mexico)], E-mail: rogelior@servidor.unam.mx

    2007-12-20

    The defect-induced luminescence properties of silica samples prepared by the sol-gel method and doped with Co(II) are reported. Silica monoliths doped with different concentrations of Co(II) were laser irradiated (He-Ne 632.8 nm) producing fluorescence. However, this fluorescence is exponentially reduced with the irradiation time, to practically disappear. The rate the fluorescence decays can be well modeled with a double exponential function of the irradiation time, containing two different relaxation times; a baseline is also required to take into account some residual fluorescence. The characteristic times involved in this luminescence quenching process are in the range of seconds. This luminescence suppression can be associated to the local heating produced by the laser irradiation when focused in a small area (2 {mu}m in diameter) on the sample. This heating process reduces physical (grain boundaries, surface states) and chemical (oxygen vacancies produced by the dopant) defects in the sample.

  10. Defect-Induced Photoluminescence Enhancement and Corresponding Transport Degradation in Individual Suspended Carbon Nanotubes

    Science.gov (United States)

    Wang, Bo; Shen, Lang; Yang, Sisi; Chen, Jihan; Echternach, Juliana; Dhall, Rohan; Kang, DaeJin; Cronin, Stephen

    2018-05-01

    This paper is a contribution to the Physical Review Applied collection in memory of Mildred S. Dresselhaus. The utilization of defects in carbon nanotubes to improve their photoluminescence efficiency has become a widespread study of the realization of efficient light-emitting devices. Here, we report a detailed comparison of the defects in nanotubes (quantified by Raman spectroscopy) and photoluminescence (PL) intensity of individual suspended carbon nanotubes (CNTs). We also evaluate the impact of these defects on the electron or hole transport in the nanotubes, which is crucial for the ultimate realization of optoelectronic devices. We find that brightly luminescent nanotubes exhibit a pronounced D-band in their Raman spectra, and vice versa, dimly luminescent nanotubes exhibit almost no D-band. Here, defects are advantageous for light emission by trapping excitons, which extend their lifetimes. We quantify this behavior by plotting the PL intensity as a function of the ID /IG -band Raman intensity ratio, which exhibits a Lorentzian distribution peaked at ID /IG=0.17 . For CNTs with a ID /IG ratio >0.25 , the PL intensity decreases, indicating that above some critical density, nonradiative recombination at defect sites dominates over the advantages of exciton trapping. In an attempt to fabricate optoelectronic devices based on these brightly luminescent CNTs, we transfer these suspended CNTs to platinum electrodes and find that the brightly photoluminescent nanotubes exhibit nearly infinite resistance due to these defects, while those without bright photoluminescence exhibit finite resistance. These findings indicate a potential limitation in the use of brightly luminescent CNTs for optoelectronic applications.

  11. Chiral filtration-induced spin/valley polarization in silicene line defects

    Science.gov (United States)

    Ren, Chongdan; Zhou, Benhu; Sun, Minglei; Wang, Sake; Li, Yunfang; Tian, Hongyu; Lu, Weitao

    2018-06-01

    The spin/valley polarization in silicene with extended line defects is investigated according to the chiral filtration mechanism. It is shown that the inner-built quantum Hall pseudo-edge states with identical chirality can serve as a chiral filter with a weak magnetic field and that the transmission process is restrained/strengthened for chiral states with reversed/identical chirality. With two parallel line defects, which act as natural chiral filtration, the filter effect is greatly enhanced, and 100% spin/valley polarization can be achieved.

  12. [Use of the induced membrane technique for the treatment of bone defects in the hand or wrist, in emergency].

    Science.gov (United States)

    Flamans, B; Pauchot, J; Petite, H; Blanchet, N; Rochet, S; Garbuio, P; Tropet, Y; Obert, L

    2010-10-01

    A prospective study is reported concerning 11 cases of bone defect of the hand and wrist treated by the induced membrane technique. Ten men and one woman with an average age of 49 yrs (17-72) sustained a high-energy trauma with severe mutilation of digit and hand but with intact pulp. Eight cases of open finger fractures with composite loss of substance and three cases of bone and joint infection (thumb, wrist, fifth finger) were included. All cases were treated by the induced membrane technique which consists in stable fixation, flap if necessary, and in filling the bone defect by a cement methyl methacrylate polymere (PMMA) spacer. A secondary procedure at two months is needed where the cement is removed and the void is filled by cancellous bone. The key point of this induced membrane technique is to respect the foreign body membrane which formed around the cement spacer creating a biologic chamber. Bone union was evaluated prospectively by X-ray and CT scan by a surgeon not involved in the treatment. Failure was defined as non-union at one year, or uncontrolled sepsis at one month. Two cases failed to achieve bone union. No septic complications occurred and all septic cases were controlled. In nine cases, bone union was achieved within four months (three to 12). Evidence of osteoid formation was determined by a bone biopsy in one case. Masquelet first reported 35 cases of large tibial non-union defects treated by the induced membrane technique. The cement spacer promotes foreign body membrane induction constituting a biological chamber. Works on animal models reported by Pellissier and Viateau demonstrated membrane properties: secretion of growths factors (VEGF, TGF beta1, BMP2) and osteoinductive cellular activity. The induced membrane seems to mimic a neoperiosteum. This technique is useful in emergency or septic conditions where bone defects cannot be treated by shortening. It avoids microsurgery and is limited by availability of cancellous bone. Copyright

  13. Correlation between morphological defects, electron beam-induced current imaging, and the electrical properties of 4H-SiC Schottky diodes

    International Nuclear Information System (INIS)

    Wang, Y.; Ali, G.N.; Mikhov, M.K.; Vaidyanathan, V.; Skromme, B.J.; Raghothamachar, B.; Dudley, M.

    2005-01-01

    Defects in SiC degrade the electrical properties and yield of devices made from this material. This article examines morphological defects in 4H-SiC and defects visible in electron beam-induced current (EBIC) images and their effects on the electrical characteristics of Schottky diodes. Optical Nomarski microscopy and atomic force microscopy were used to observe the morphological defects, which are classified into 26 types based on appearance alone. Forward and reverse current-voltage characteristics were used to extract barrier heights, ideality factors, and breakdown voltages. Barrier heights decrease about linearly with increasing ideality factor, which is explained by discrete patches of low barrier height within the main contact. Barrier height, ideality, and breakdown voltage all degrade with increasing device diameter, suggesting that discrete defects are responsible. Electroluminescence was observed under reverse bias from microplasmas associated with defects containing micropipes. EBIC measurements reveal several types of features corresponding to recombination centers. The density of dark spots observed by EBIC correlates strongly with ideality factor and barrier height. Most morphological defects do not affect the reverse characteristics when no micropipes are present, but lower the barrier height and worsen the ideality factor. However, certain multiple-tailed defects, irregularly shaped defects and triangular defects with 3C inclusions substantially degrade both breakdown voltage and barrier height, and account for most of the bad devices that do not contain micropipes. Micropipes in these wafers are also frequently found to be of Type II, which do not run parallel to the c axis

  14. Genetic reconstitution of the human Adenovirus type 2 temperature-sensitive 1 mutant defective in endosomal escape

    Directory of Open Access Journals (Sweden)

    Gastaldelli Michele

    2009-10-01

    Full Text Available Abstract Human Adenoviruses infect the upper and lower respiratory tracts, the urinary and digestive tracts, lymphoid systems and heart, and give rise to epidemic conjunctivitis. More than 51 human serotypes have been identified to-date, and classified into 6 species A-F. The species C Adenoviruses Ad2 and Ad5 (Ad2/5 cause upper and lower respiratory disease, but how viral structure relates to the selection of particular infectious uptake pathways is not known. An adenovirus mutant, Ad2-ts1 had been isolated upon chemical mutagenesis in the past, and shown to have unprocessed capsid proteins. Ad2-ts1 fails to package the viral protease L3/p23, and Ad2-ts1 virions do not efficiently escape from endosomes. It had been suggested that the C22187T point mutation leading to the substitution of the conserved proline 137 to leucine (P137L in the L3/p23 protease was at least in part responsible for this phenotype. To clarify if the C22187T mutation is necessary and sufficient for the Ad2-ts1 phenotype, we sequenced the genes encoding the structural proteins of Ad2-ts1, and confirmed that the Ad2-ts1 DNA carries the point mutation C22187T. Introduction of C22187T to the wild-type Ad2 genome in a bacterial artificial chromosome (Ad2-BAC gave Ad2-BAC46 virions with the full Ad2-ts1 phenotype. Reversion of Ad2-BAC46 gave wild-type Ad2 particles indicating that P137L is necessary and sufficient for the Ad2-ts1 phenotype. The kinetics of Ad2-ts1 uptake into cells were comparable to Ad2 suggesting similar endocytic uptake mechanisms. Surprisingly, infectious Ad2 or Ad5 but not Ad2-ts1 uptake required CALM (clathrin assembly lymphoid myeloid protein, which controls clathrin-mediated endocytosis and membrane transport between endosomes and the trans-Golgi-network. The data show that no other mutations than P137L in the viral protease are necessary to give rise to particles that are defective in capsid processing and endosomal escape. This provides a basis for

  15. Annealing of hydrogen-induced defects in RF-plasma-treated Si wafers: ex situ and in situ transmission electron microscopy studies

    International Nuclear Information System (INIS)

    Ghica, C; Nistor, L C; Vizireanu, S; Dinescu, G

    2011-01-01

    The smart-cut(TM) process is based on inducing and processing structural defects below the free surface of semiconductor wafers. The necessary defects are currently induced by implantation of light elements such as hydrogen or helium. An alternative softer way to induce shallow subsurface defects is by RF-plasma hydrogenation. To facilitate the smart-cut process, the wafers containing the induced defects need to be subjected to an appropriate thermal treatment. In our experiments, (0 0 1) Si wafers are submitted to 200 and 50 W hydrogen RF-plasma and are subsequently annealed. The samples are studied by transmission electron microscopy (TEM), before and after annealing. The plasma-introduced defects are {1 1 1} and {1 0 0} planar-like defects and nanocavities, all of them involving hydrogen. Many nanocavities are aligned into strings almost parallel to the wafer surface. The annealing is performed either by furnace thermal treatment at 550 deg. C, or by in situ heating in the electron microscope at 450, 650 and 800 deg. C during the TEM observations. The TEM microstructural studies indicate a partial healing of the planar defects and a size increase of the nanometric cavities by a coalescence process of the small neighbouring nanocavities. By annealing, the lined up nanometric voids forming chains in the as-hydrogenated sample coalesced into well-defined cracks, mostly parallel to the wafer surface.

  16. Interactome of Obesity: Obesidome : Genetic Obesity, Stress Induced Obesity, Pathogenic Obesity Interaction.

    Science.gov (United States)

    Geronikolou, Styliani A; Pavlopoulou, Athanasia; Cokkinos, Dennis; Chrousos, George

    2017-01-01

    Obesity is a chronic disease of increasing prevalence reaching epidemic proportions. Genetic defects as well as epigenetic effects contribute to the obesity phenotype. Investigating gene (e.g. MC4R defects)-environment (behavior, infectious agents, stress) interactions is a relative new field of great research interest. In this study, we have made an effort to create an interactome (henceforth referred to as "obesidome"), where extrinsic stressors response, intrinsic predisposition, immunity response to inflammation and autonomous nervous system implications are integrated. These pathways are presented in one interactome network for the first time. In our study, obesity-related genes/gene products were found to form a complex interactions network.

  17. Electrospun biodegradable microfibers induce new collagen formation in a rat abdominal wall defect model

    DEFF Research Database (Denmark)

    Tarpø, Cecilie Lærke Glindtvad; Chen, Menglin; Nygaard, Jens Vinge

    2018-01-01

    and effect on collagen and elastin production of a degradable mesh releasing basic fibroblast growth factor (bFGF). Implantation of biodegradable mesh with or without bFGF in their core has been conducted in 40 rats in an abdominal wall defect model. Samples were explanted after 4, 8, and 24 weeks...

  18. Electronic excitation induced defect dynamics in HfO2 based MOS devices investigated by in-situ electrical measurements

    Science.gov (United States)

    Manikanthababu, N.; Vajandar, S.; Arun, N.; Pathak, A. P.; Asokan, K.; Osipowicz, T.; Basu, T.; Nageswara Rao, S. V. S.

    2018-03-01

    In-situ I-V and C-V characterization studies were carried out to determine the device quality of atomic layer deposited HfO2 (2.7 nm)/SiO2 (0.6 nm)/Si-based metal oxide semiconductor devices during 120 MeV Ag ion irradiation. The influence of various tunneling mechanisms has been investigated by analyzing the I-V characteristics as a function of ion fluence. The nature of the defects created is tentatively identified by the determination of the significant tunneling processes. While the ion induced annealing of defects is observed at lower fluences, ion induced intermixing and radiation damage is found to be significant at higher fluences. The C-V characteristics also reveal significant changes at the interface and oxide trap densities: an increase in the oxide layer thickness occurs through the formation of an HfSiO interlayer. The interlayer is due to the swift heavy ion induced intermixing, which has been confirmed by X-TEM and X-ray photoelectron spectroscopy measurements.

  19. Fyn kinase genetic ablation causes structural abnormalities in mature retina and defective Müller cell function.

    Science.gov (United States)

    Chavez-Solano, Marbella; Ibarra-Sanchez, Alfredo; Treviño, Mario; Gonzalez-Espinosa, Claudia; Lamas, Monica

    2016-04-01

    Fyn kinase is widely expressed in neuronal and glial cells of the brain, where it exerts multiple functional roles that affect fundamental physiological processes. The aim of our study was to investigate the, so far unknown, functional role of Fyn in the retina. We report that Fyn is expressed, in vivo, in a subpopulation of Müller glia. We used a mouse model of Fyn genetic ablation and Müller-enriched primary cultures to demonstrate that Fyn deficiency induces morphological alterations in the mature retina, a reduction in the thickness of the outer and inner nuclear layers and alterations in postnatal Müller cell physiology. These include shortening of Müller cell processes, a decrease in cell proliferation, inactivation of the Akt signal transduction pathway, a reduced number of focal adhesions points and decreased adhesion of these cells to the ECM. As abnormalities in Müller cell physiology have been previously associated to a compromised retinal function we evaluated behavioral responses to visual stimulation. Our results associate Fyn deficiency with impaired visual optokinetic responses under scotopic and photopic light conditions. Our study reveals novel roles for Fyn kinase in retinal morphology and Müller cell physiology and suggests that Fyn is required for optimal visual processing. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Formation of radiation-induced point defects in silicon doped thin films upon ion implantation and activating annealing

    International Nuclear Information System (INIS)

    Bublik, V.T.; Shcherbachev, K.D.; Komarnitskaya, E.A.; Parkhomenko, Yu.N.; Vygovskaya, E.A.; Evgen'ev, S.B.

    1999-01-01

    The formation and relaxation processes for radiation-induced defects in the implantation of 50 keV Si + ions into gallium arsenide and subsequent 10-min annealing in arsine at 850 deg. C have been studied by the triple-crystal X-ray diffractometry and secondary-ion mass spectroscopy techniques. It is shown that the existence of the vacancy-enriched layer stimulating diffusion of introduced dopants into the substrate surface can significantly affect the distribution profile of the dopant in the course of preparation of thin implanted layers

  1. Defect-induced magnetism in undoped and Mn-doped wide band gapzinc oxide grown by aerosol spray pyrolysis

    CSIR Research Space (South Africa)

    Motaung, DE

    2014-08-01

    Full Text Available Surface Science Vol. 311, pp 14-26 Defect-induced magnetism in undoped and Mn-doped wide band gapzinc oxide grown by aerosol spray pyrolysis D.E. Motaunga,∗, I. Kortidise, D. Papadakie, S.S. Nkosib,∗∗, G.H. Mhlongoa,J. Wesley-Smitha, G.F. Malgasc, B....W. Mwakikungaa, E. Coetseed, H.C. Swartd,G. Kiriakidise,f, S.S. Raya aDST/CSIR Nanotechnology Innovation Centre, National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, P.O. Box 395,Pretoria 0001, South Africa b...

  2. Preferential Au precipitation at deformation-induced defects in Fe–Au and Fe–Au–B–N alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S., E-mail: S.Zhang-1@tudelft.nl [Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Langelaan, G. [Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Brouwer, J.C.; Sloof, W.G. [Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft (Netherlands); Brück, E. [Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Zwaag, S. van der [Novel Aerospace Materials Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands); Dijk, N.H. van [Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)

    2014-01-25

    Highlights: • Fe–Au–B–N forms a good model alloy system for self healing of deformation damage. • Solute Au atoms exclusively precipitate at grain boundaries, cracks and cavities. • XPS indicates a strong tendency for Au segregation on free surfaces at 550 °C. • Interstitial B and N form hexagonal BN on free surfaces at 550 °C. • Selective Au precipitation at open volume defects can cause autonomous repair. -- Abstract: The influence of deformation-induced defects on the isothermal precipitation of Au was studied in high-purity Fe–Au and Fe–Au–B–N alloys. Preferential Au precipitation upon annealing at 550 °C is observed at local plastic indentations. In fractured Fe–Au–B–N, solute Au atoms were found to heterogeneously precipitate at grain boundaries and local micro-cracks. This is supported by in-situ creep tests that showed a strong tendency for Au precipitation at cracks and cavities also formed during creep loading at 550 °C. Complementary X-ray photoelectron spectroscopy experiments indicate a strong tendency of Au, B and N segregation onto free surface during aging. The observed site-specific precipitation of Au holds interesting opportunities for defect healing in steels subjected to creep deformation.

  3. Prospect of Induced Pluripotent Stem Cell Genetic Repair to Cure Genetic Diseases

    Directory of Open Access Journals (Sweden)

    Jeanne Adiwinata Pawitan

    2012-01-01

    Full Text Available In genetic diseases, where the cells are already damaged, the damaged cells can be replaced by new normal cells, which can be differentiated from iPSC. To avoid immune rejection, iPSC from the patient’s own cell can be developed. However, iPSC from the patients’s cell harbors the same genetic aberration. Therefore, before differentiating the iPSCs into required cells, genetic repair should be done. This review discusses the various technologies to repair the genetic aberration in patient-derived iPSC, or to prevent the genetic aberration to cause further damage in the iPSC-derived cells, such as Zn finger and TALE nuclease genetic editing, RNA interference technology, exon skipping, and gene transfer method. In addition, the challenges in using the iPSC and the strategies to manage the hurdles are addressed.

  4. Point defects induced in LiF by low energy electrons

    International Nuclear Information System (INIS)

    Baldacchini, Giuseppe; Montereali, Rosa Maria; Scacco, Augusto; Cremona, Marco; D'Auria, Giuliano.

    1997-09-01

    A systematic study of the coloring of LiF crystals and films irradiated by 3 keV electrons at various temperatures was carried out analysing their absorption and luminescence spectra. The three stage behaviour of the F coloring curve as a function of the irradiation dose was revealed and the saturation of the process was identified for the first time with this kind of radiation. The kinetics of the defect formation confirmed the expectations derived from the most comprehensive theoretical model developed to explain the coloring process. The irradiation temperature was found to have an influence on both the proportion of different defects created and on their stability and the overall coloring efficiency turned out to be higher when the irradiation was performed on films. Various explanations to these observations are put forward and discussed

  5. Influence of ion irradiation induced defects on mechanical properties of copper nanowires

    International Nuclear Information System (INIS)

    Li, Weina; Sun, Lixin; Xue, Jianming; Wang, Jianxiang; Duan, Huiling

    2013-01-01

    The mechanical properties of copper nanowires irradiated with energetic ions have been investigated by using molecular dynamics simulations. The Cu ions with energies ranging from 0.2 to 8.0 keV are used in our simulation, and both the elastic properties and yields under tension and compression are analyzed. The results show that two kinds of defects, namely point defects and stacking faults, appear in the irradiated nanowires depending on the incident ion energy. The Young modulus is significantly reduced by the ion irradiation, and the reduction magnitude depends on the vacancy number, which is determined by the ion energy. Moreover, the irradiated nanowires yield at a smaller strain, compared with the unirradiated nanowire. The mechanism for these changes are also discussed

  6. Point defects induced in LiF by low energy electrons

    Energy Technology Data Exchange (ETDEWEB)

    Baldacchini, Giuseppe; Montereali, Rosa Maria [ENEA, Centro Ricerche Frascati, Rome (Italy); Scacco, Augusto [Rome, Univ. (Italy). Dipt. di Fisica]|[INFM, Rome (Italy); Cremona, Marco; D`Auria, Giuliano

    1997-09-01

    A systematic study of the coloring of LiF crystals and films irradiated by 3 keV electrons at various temperatures was carried out analysing their absorption and luminescence spectra. The three stage behaviour of the F coloring curve as a function of the irradiation dose was revealed and the saturation of the process was identified for the first time with this kind of radiation. The kinetics of the defect formation confirmed the expectations derived from the most comprehensive theoretical model developed to explain the coloring process. The irradiation temperature was found to have an influence on both the proportion of different defects created and on their stability and the overall coloring efficiency turned out to be higher when the irradiation was performed on films. Various explanations to these observations are put forward and discussed.

  7. Defect-Induced Luminescence of a Self-Activated Borophosphate Phosphor

    Science.gov (United States)

    Han, Bing; Liu, Beibei; Dai, Yazhou; Zhang, Jie

    2018-05-01

    A self-activated borophosphate phosphor Ba3BPO7 was prepared via typical solid-state reaction in thermal-carbon reduction atmosphere. The structural and luminescence properties were investigated using x-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and photoluminescence spectroscopy. Upon excitation with ultraviolet (UV) light, the as-prepared phosphor shows bright greenish-yellow emission with a microsecond-level fluorescence lifetime, which could result from the oxygen vacancies produced in the process of solid-state synthesis. The possible luminescence mechanism is proposed. Through the introduction of defects in the host, this work realizes visible luminescence in a pure borophosphate compound that does not contain any rare earth or transition metal activators, so it is helpful to develop defect-related luminescent materials in view of energy conservation and environmental protection for sustainable development.

  8. Defect induced ferromagnetism in MgO nanoparticles studied by optical and positron annihilation spectroscopy

    Science.gov (United States)

    Kumar, Nitesh; Sanyal, D.; Sundaresan, A.

    2009-08-01

    Positron annihilation spectroscopy has been used to explore the nature of defects and to estimate the defect concentrations in ferromagnetic MgO nanoparticles. Our experimental results show that Mg vacancies or Mg vacancy concentration are present approximately at the concentration of 3.4 × 10 16 cm -3 in the nano-crystalline MgO which is twice the value that obtained for bulk sample. This is in correlation with the decrease of the intensity of blue luminescence and the saturation magnetic moment with increasing particle size. These results clearly demonstrate that the origin of magnetic moment and thus the ferromagnetism in MgO nanoparticles is due to Mg related vacancies at the surface of the particles.

  9. Vibrational and electronic spectroscopy of ion-implantation-induced defects in fused silica and crystalline quartz

    International Nuclear Information System (INIS)

    Arnold, G.W.

    1978-01-01

    Defects produced by implantation of various atomic species in fused and crystalline SiO 2 were studied using infrared reflection spectroscopy (IRS) with UV-visible spectroscopy. We observe a new vibrational band at 830 cm -1 which is tentatively associated with the creation of two nonbridging O atoms in SiO 4 units. Numerous chemical effects were also observed, including evidence for chemical incorporation of Li and anomalously large O-vacancy production for Al + , B + and Si + implantation

  10. Congenital Heart Defects (For Parents)

    Science.gov (United States)

    ... to be associated with genetic disorders, such as Down syndrome . But the cause of most congenital heart defects isn't known. While they can't be prevented, many treatments are available for the defects and related health ...

  11. Naturally occurring and radiation-induced tumors in SPF mice, and genetic influence in radiation leukemogenesis

    International Nuclear Information System (INIS)

    Kasuga, T.

    1979-01-01

    The data obtained so far in this study point to a strong genetic influence not only on the types and incidence of naturally occurring and radiation-induced tumors but also on radiation leukemogenesis. (Auth.)

  12. Acquisition of Genetic Aberrations by Activation-Induced Cytidine Deaminase (AID) during Inflammation-Associated Carcinogenesis

    International Nuclear Information System (INIS)

    Takai, Atsushi; Marusawa, Hiroyuki; Chiba, Tsutomu

    2011-01-01

    Genetic abnormalities such as nucleotide alterations and chromosomal disorders that accumulate in various tumor-related genes have an important role in cancer development. The precise mechanism of the acquisition of genetic aberrations, however, remains unclear. Activation-induced cytidine deaminase (AID), a nucleotide editing enzyme, is essential for the diversification of antibody production. AID is expressed only in activated B lymphocytes under physiologic conditions and induces somatic hypermutation and class switch recombination in immunoglobulin genes. Inflammation leads to aberrant AID expression in various gastrointestinal organs and increased AID expression contributes to cancer development by inducing genetic alterations in epithelial cells. Studies of how AID induces genetic disorders are expected to elucidate the mechanism of inflammation-associated carcinogenesis

  13. Effect of He+ fluence on surface morphology and ion-irradiation induced defect evolution in 7075 aluminum alloys

    Science.gov (United States)

    Ni, Kai; Ma, Qian; Wan, Hao; Yang, Bin; Ge, Junjie; Zhang, Lingyu; Si, Naichao

    2018-02-01

    The evolution of microstructure for 7075 aluminum alloys with 50 Kev helium ions irradiation were studied by using optical microscopy (OM), scanning electron microscopy (SEM), x-ray diffraction (XRD) and transmission electron microscopy (TEM). The fluences of 1 × 1015, 1 × 1016 and 1 × 1017 ions cm-2 were selected, and irradiation experiments were conducted at room temperatures. The transmission process of He+ ions was simulated by using SRIM software, including distribution of ion ranges, energy losses and atomic displacements. Experimental results show that irradiated pits and micro-cracks were observed on irradiation sample surface, and the size of constituent particles (not including Mg2Si) decreased with the increasing dose. The x-ray diffraction results of the pair of peaks is better resolved in irradiated samples might indicate that the stressed structure consequence due to crystal defects (vacancies and interstitials) after He+ implantation. TEM observation indicated that the density of MgZn2 phase was significantly reduced after helium ion irradiation which is harmful to strength. Besides, the development of compressive stress produced a large amount of dislocation defects in the 1015 ions cm-2 sample. Moreover, higher fluence irradiation produced more dislocations in sample. At fluence of 1016 ions cm-2, dislocation wall formed by dislocation slip and aggregation in the interior of grains, leading to the refinement of these grains. As fluence increased to 1017 ions cm-2, dislocation loops were observed in pinned dislocation. Moreover, dislocation as effective defect sink, irradiation-induced vacancy defects aggregated to these sinks, and resulted in the formation of helium bubbles in dislocation.

  14. Study by electrical resistivity measurements of the radiation induced defects in gold-copper alloys

    International Nuclear Information System (INIS)

    Alamo, A.

    1983-09-01

    Point defect production rate in Cu 3 Au and CuAu ordered and disordered alloys was studied by electrical resistivity measurements, as function of electron energy ranging from 0.4 to 2.5 MeV. The irradiations were performed at 20 K. The production curves are analysed using a displacement model for diatomic materials and the following values are found for the average displacement threshold energies: Esub(d)sup(Cu) approximately 22 eV and Esub(d)sup(Au) approximately 18 eV, for both alloys. Elementary defect migration was examined during isochronal annealing performed after irradiations. A simple type of self-interstitial seems to migrate in the ordered alloys: probably a split-interstitial of Cu-Cu type. Interstitial migration seems to be very difficult and complex in the disordered alloys. Vacancy mobility was detected after recovery at temperature above 300 K and was responsible of an increase of long range order. Fast neutron irradiations at 20 K produce disordering in the initially ordered alloys. Ratios of 38 and 18 antistructure defects per atomic displacement are estimated for Cu 3 Au and CuAu respectively [fr

  15. Low-temperature electron irradiation induced defects in gallium arsenide: bulk and surface acoustic wave studies

    International Nuclear Information System (INIS)

    Brophy, M.J. Jr.

    1985-01-01

    Irradiation of GaAs with 2.25 to 2.5 MeV electrons at temperatures below 190 K produces two peaks in ultrasonic attenuation versus temperature. The defects responsible for both peaks have trigonal symmetry and were observed in n-type and semi-insulating GaAs with bulk and surface acoustic waves (SAW) respectively. Bulk waves at eight frequencies between 9 and 130 MHz and SAW at 73 and 145 MHz were used. The reorientation kinetics of both peaks follow the Arrhenius law. The annealing of both peaks was studied with isochronal and isothermal anneals in the temperature range 200 to 335 K. Peak I anneals with a spectrum of activation energies in the range 0.7-1.1 eV between 220 and 335 K. Peak II anneals with a single activation energy of about 1.1 eV above 300K. The different annealing characteristics indicate that these peaks represent two distinct defects. The annealing above 300 K has not been seen in electrical resistivity measurements, but was observed in earlier length change experiments. Irradiation of GaAs:Cr produces no Cr-radiation defect complexes. The attenuation peak associated with Cr 2+ decrease with electron dose, but starts to recover at 150 K

  16. Defect-induced local variation of crystal phase transition temperature in metal-halide perovskites.

    Science.gov (United States)

    Dobrovolsky, Alexander; Merdasa, Aboma; Unger, Eva L; Yartsev, Arkady; Scheblykin, Ivan G

    2017-06-26

    Solution-processed organometal halide perovskites are hybrid crystalline semiconductors highly interesting for low-cost and efficient optoelectronics. Their properties are dependent on the crystal structure. Literature shows a variety of crystal phase transition temperatures and often a spread of the transition over tens of degrees Kelvin. We explain this inconsistency by demonstrating that the temperature of the tetragonal-to-orthorhombic phase transition in methylammonium lead triiodide depends on the concentration and nature of local defects. Phase transition in individual nanowires was studied by photoluminescence microspectroscopy and super-resolution imaging. We propose that upon cooling from 160 to 140 K, domains of the crystal containing fewer defects stay in the tetragonal phase longer than highly defected domains that readily transform to the high bandgap orthorhombic phase at higher temperatures. The existence of relatively pure tetragonal domains during the phase transition leads to drastic photoluminescence enhancement, which is inhomogeneously distributed across perovskite microcrystals.Understanding crystal phase transition in materials is of fundamental importance. Using luminescence spectroscopy and super-resolution imaging, Dobrovolsky et al. study the transition from the tetragonal to orthorhombic crystal phase in methylammonium lead triiodide nanowires at low temperature.

  17. Liver mitochondrial dysfunction and electron transport chain defect induced by high dietary copper in broilers.

    Science.gov (United States)

    Yang, Fan; Cao, Huabin; Su, Rongsheng; Guo, Jianying; Li, Chengmei; Pan, Jiaqiang; Tang, Zhaoxin

    2017-09-01

    Copper is an important trace mineral in the diet of poultry due to its biological activity. However, limited information is available concerning the effects of high copper on mitochondrial dysfunction. In this study, 72 broilers were used to investigate the effects of high dietary copper on liver mitochondrial dysfunction and electron transport chain defect. Birds were fed with different concentrations [11, 110, 220, and 330 mg of copper/kg dry matter (DM)] of copper from tribasic copper chloride (TBCC). The experiment lasted for 60 d. Liver tissues on d 60 were subjected to histopathological observation. Additionally, liver mitochondrial function was recorded on d 12, 36, and 60. Moreover, a site-specific defect in the electron transport chain in liver mitochondria was also identified by using various chemical inhibitors of mitochondrial respiration. The results showed different degrees of degeneration, mitochondrial swelling, and high-density electrons in hepatocytes. In addition, the respiratory control ratio (RCR) and oxidative phosphorylation rate (OPR) in liver mitochondria increased at first and then decreased in high-dose groups. Moreover, hydrogen peroxide (H2O2) generation velocity in treated groups was higher than that in control group, which were magnified by inhibiting electron transport at Complex IV. The results indicated that high dietary copper could decline liver mitochondrial function in broilers. The presence of a site-specific defect at Complex IV in liver mitochondria may be responsible for liver mitochondrial dysfunction caused by high dietary copper. © 2017 Poultry Science Association Inc.

  18. Advances in improvement of stress tolerance by induced mutation and genetic transformation in alfalfa

    International Nuclear Information System (INIS)

    Huang Xin; Ye Hongxia; Shu Xiaoli; Wu Dianxing

    2008-01-01

    In order to provide references for stress-tolerant breeding of alfalfa, genetic basis of stress-tolerant traits was briefly introduced and advanced in improvement of stress-tolerance by induced mutation and genetic transformation in alfalfa were reviewed. (authors)

  19. Stress-induced variation in evolution: from behavioural plasticity to genetic assimilation.

    Science.gov (United States)

    Badyaev, Alexander V

    2005-05-07

    Extreme environments are closely associated with phenotypic evolution, yet the mechanisms behind this relationship are poorly understood. Several themes and approaches in recent studies significantly further our understanding of the importance that stress-induced variation plays in evolution. First, stressful environments modify (and often reduce) the integration of neuroendocrinological, morphological and behavioural regulatory systems. Second, such reduced integration and subsequent accommodation of stress-induced variation by developmental systems enables organismal 'memory' of a stressful event as well as phenotypic and genetic assimilation of the response to a stressor. Third, in complex functional systems, a stress-induced increase in phenotypic and genetic variance is often directional, channelled by existing ontogenetic pathways. This accounts for similarity among individuals in stress-induced changes and thus significantly facilitates the rate of adaptive evolution. Fourth, accumulation of phenotypically neutral genetic variation might be a common property of locally adapted and complex organismal systems, and extreme environments facilitate the phenotypic expression of this variance. Finally, stress-induced effects and stress-resistance strategies often persist for several generations through maternal, ecological and cultural inheritance. These transgenerational effects, along with both the complexity of developmental systems and stressor recurrence, might facilitate genetic assimilation of stress-induced effects. Accumulation of phenotypically neutral genetic variance by developmental systems and phenotypic accommodation of stress-induced effects, together with the inheritance of stress-induced modifications, ensure the evolutionary persistence of stress-response strategies and provide a link between individual adaptability and evolutionary adaptation.

  20. Process of defect formation in alkaline halogenides contaminated with Eu2+ induced by non ionizing radiation

    International Nuclear Information System (INIS)

    Pedroza M, M.; Melendrez, R.; Barboza F, M.; Castaneda, B.

    2004-01-01

    The creation of defects in polluted alkaline halogenides with divalent impurities exposed to ionizing radiation is explained by means of the creation of auto trapped excitons (STE), which can be formed by means of the excitement of the halogen ion or through the trapping of electrons in centers V K taken place during the process of ionization of the halogen ion. The luminescent recombination of the exciton auto trapped produces a characteristic exciton luminescence and the recombination non radiative causes the formation of the Frenkel type defects, even of centers F - H. Experimentally has been demonstrated that the same type of glasses, exposed to radiation non ionizing of the type UV of around 230 nm, they produce defects similar Frenkel. The situation is interesting all time that photons of 230 nm (5.3 eV) they cannot create excitons directly since they are in an energy level of approximately 2.4 inferior eV to the necessary energy for the production of the same ones. In order to investigating the type of process of creation of defects with UV light energy below the energy of the band prohibited in polluted alkaline halogenides with Eu 2+ , mainly looking for experimental information that allows to explain the creation of defects taken place by the radiation non ionizing, one carries out the present work. It was found that, independently of the energy of the radiation used for the excitement, the emission comes from the transition 4f 6 5d(t 2g )-4f 7 ( 8 S 7/2 ) of the ion Eu 2+ characterized by a wide band centered in 420 nm and an additional component in 460 nm of possibly intrinsic origin. It was determined that so much the F centers and F z participate in the thermoluminescent processes and of optically stimulated luminescence, achieving to identify those peaks of Tl strictly associated to the F centers (peak in 470 K for the KCl: Eu 2+ ) and F z (peak in 370 K). Also, by means of a process of selective photo stimulation evidence was obtained that the F

  1. Genetic predisposition for radiation-induced bone tumors

    International Nuclear Information System (INIS)

    Rosemann, M.; Luz, A.; Kuosaite, V.; Favor, J.; Atkinson, M.J.; Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg

    1999-01-01

    The interaction between environmental factors and genetic determinants is crucial for the development of malignant tumours. However, the hereditary factors involved in the development of cancer that have been recognised so far are only responsible for at the most ten percent of tumours. It is still a matter of dispute whether the remaining 90 percent - so-called sporadic tumours - really have a cause that is free of genetic influence. There are good reasons for believing that there are a large number of genes in the human genome that confer resistance or susceptibility for tumorigenesis, and thus lead to natural genetic variability. (orig.) [de

  2. Inductively coupled plasma-induced defects in n-type GaN studied from Schottky diode characteristics

    International Nuclear Information System (INIS)

    Nakamura, W.; Tokuda, Y.; Ueda, H.; Kachi, T.

    2006-01-01

    Inductively coupled plasma-(ICP-)induced defects in n-type GaN have been studied from current-voltage (I-V) characteristics and deep-level transient spectroscopy (DLTS) for Schottky diodes fabricated on etched surfaces. The samples after ICP etching show the ohmic I-V characteristics. Schottky characteristics are obtained after annealing at 600 and 800 deg. C in N 2 , but are not restored to that of the control samples. DLTS shows that the effect of ICP etching is small on the region beyond 80 nm from the surface. These results suggest that there remain ICP-induced damage in the near-surface region after thermal annealing

  3. Ion species dependence of the implantation-induced defects in ZnO studied by a slow positron beam

    International Nuclear Information System (INIS)

    Chen, Z.Q.; Maekawa, M.; Kawasuso, A.; Naramoto, H.

    2007-01-01

    In this work, we implanted B + , O + , Al + , and P + ions into ZnO with energy of 50-380 keV and total doses of 4 x 10 15 cm -2 for each ion. The implantation-induced defects and their thermal recovery were studied using a slow positron beam. Vacancy clusters are produced in all the implanted samples. It is found that the thermal recovery of these vacancies induced by different ions shows much difference. In case of B + and Al + -implantation, the vacancy clusters agglomerate to much larger size and might evolve to microvoids during annealing. However, for O + and P + ions, which are heavier than B + and Al + , the vacancies show a much weaker agglomeration process. The mechanism of such difference is discussed. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Influence of ion beam irradiation induced defects on the structural, optical and electrical properties of tellurium nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Narinder [Department of Physics, Chaudhary Devi Lal University, Sirsa, 125055 (India); Department of Physics, Haryana College of Technology & Management, Kaithal, 136027 (India); Kumar, Rajesh [Department of Physics, RN College of Engineering & Technology, Madlauda, 132104 (India); Kumar, Sushil, E-mail: sushil_phys@rediffmail.com [Department of Physics, Chaudhary Devi Lal University, Sirsa, 125055 (India); Chakarvarti, S.K. [Research and Development, Manav Rachana International University, Faridabad, 121001 (India)

    2016-11-01

    In this study, tellurium nanowires were electrodeposited into the polymer membranes from aqueous acidic bath containing HTeO{sub 2}{sup +} ions. The field emission scanning electron microscopy (FESEM) images confirmed the formation of uniform and straight nanowires. The influence of 110 MeV Ni{sup 8+} ion irradiation induced defects on the structural, optical and electrical properties of as–deposited tellurium nanowires were examined using X-ray diffraction (XRD), UV–visible absorption spectroscopy and current–voltage (I–V) measurements. The XRD data depicted the hexagonal phase of tellurium nanowires and further revealed a variation in the intensity of diffraction peaks of ion irradiated nanowires. Williamson–Hall (WH) analysis is used for convoluting the size and microstrain contributions to the width of diffraction peaks. Tellurium nanowires exhibited a distinct absorbance band in the visible region at 686 nm, while this was absent in bulk tellurium. Electrical properties of nanowires are explored on the basis of I–V curves, which revealed a significant increase in the electrical conductivity of irradiated nanowires. A possible mechanism for the enhanced electrical conductivity is the increase in carrier concentration due to thermally excited defects. The defects produced by ion irradiation play a vital role in modifying the properties of semiconducting nanowires. - Highlights: • 110 MeV Ni{sup 8+} ion beam induced changes in tellurium nanowires have been examined. • Nanowires were prepared using template electrodeposition method. • Irradiation improved the electrical conductivity of tellurium nanowires. • Mechanism for enhanced electrical conductivity of irradiated nanowires was discussed.

  5. Alpha-particle irradiation induced defects in SiO2 films of Si-SiO2 structures

    International Nuclear Information System (INIS)

    Koman, B.P.; Gal'chynskyy, O.V.; Kovalyuk, R.O.; Shkol'nyy, A.K.

    1996-01-01

    The aim of the work was to investigate alpha-particle irradiation induced defects in Si-SiO 2 structures by means of the thermostimulated discharge currents (TSDC) analysis. The object of investigation were (p-Si)-SiO 2 structures formed by a combined oxidation of the industrial p-Si wafers in dry and wet oxygen at temperature of 1150 C. The TSD currents were investigated in the temperature range between 90 and 500 K under linear heating rate. Pu 238 isotopes were the source of alpha-particles with an energy of 4-5 MeV and a density of 5.10 7 s -1 cm -2 . The TSD current curves show two peculiar maxima at about 370 and 480 K. Alpha-particle irradiation doesn't affect the general shape of the TSDC curves but leads to a shift of the maximum at 370 K and reduces the total electret charge which is accumulated in the Si-SiO 2 structures during polarization. The energy distribution function of the defects which are involved in SiO 2 polarization has been calculated. It showes that defects with activation energies of about 0.8 and 1.0 eV take part in forming the electret state, and these activation energies have certain energy distributions. It has been found that the TSDC maximum at 370 K has space charge nature and is caused by migration of hydrogen ions. In irradiated samples hydrogen and natrium ions localize on deeper trapping centres induced by alpha-particle irradiation. (orig.)

  6. Folic acid and pantothenic acid protection against valproic acid-induced neural tube defects in CD-1 mice

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Jennifer E [Department of Pharmacology and Toxicology and School of Environmental Studies, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada); Raymond, Angela M [Department of Pharmacology and Toxicology and School of Environmental Studies, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada); Winn, Louise M [Department of Pharmacology and Toxicology and School of Environmental Studies, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada)

    2006-03-01

    In utero exposure to valproic acid (VPA) during pregnancy is associated with an increased risk of neural tube defects (NTDs). Although the mechanism by which VPA mediates these effects is unknown, VPA-initiated changes in embryonic protein levels have been implicated. The objectives of this study were to investigate the effect of in utero VPA exposure on embryonic protein levels of p53, NF-{kappa}B, Pim-1, c-Myb, Bax, and Bcl-2 in the CD-1 mouse. We also evaluated the protective effects of folic acid and pantothenic acid on VPA-induced NTDs and VPA-induced embryonic protein changes in this model. Pregnant CD-1 mice were administered a teratogenic dose of VPA prior to neural tube closure and embryonic protein levels were analyzed. In our study, VPA (400 mg/kg)-induced NTDs (24%) and VPA-exposed embryos with an NTD showed a 2-fold increase in p53, and 4-fold decreases in NF-{kappa}B, Pim-1, and c-Myb protein levels compared to their phenotypically normal littermates (P < 0.05). Additionally, VPA increased the ratio of embryonic Bax/Bcl-2 protein levels (P < 0.05). Pretreatment of pregnant dams with either folic acid or pantothenic acid prior to VPA significantly protected against VPA-induced NTDs (P < 0.05). Folic acid also reduced VPA-induced alterations in p53, NF-{kappa}B, Pim-1, c-Myb, and Bax/Bcl-2 protein levels, while pantothenic acid prevented VPA-induced alterations in NF-{kappa}B, Pim-1, and c-Myb. We hypothesize that folic acid and pantothenic acid protect CD-1 embryos from VPA-induced NTDs by independent, but not mutually exclusive mechanisms, both of which may be mediated by the prevention of VPA-induced alterations in proteins involved in neurulation.

  7. Developmental defects and genomic instability after x-irradiation of wild-type and genetically modified mouse pre-implantation and early post-implantation embryos

    International Nuclear Information System (INIS)

    Jacquet, P

    2012-01-01

    Results obtained from the end of the 1950s suggested that ionizing radiation could induce foetal malformations in some mouse strains when administered during early pre-implantation stages. Starting in 1989, data obtained in Germany also showed that radiation exposure during that period could lead to a genomic instability in the surviving foetuses. Furthermore, the same group reported that both malformations and genomic instability could be transmitted to the next generation foetuses after exposure of zygotes to relatively high doses of radiation. As such results were of concern for radiation protection, we investigated this in more detail during recent years, using mice with varying genetic backgrounds including mice heterozygous for mutations involved in important cellular processes like DNA repair, cell cycle regulation or apoptosis. The main parameters which were investigated included morphological development, genomic instability and gene expression in the irradiated embryos or their own progeny. The aim of this review is to critically reassess the results obtained in that field in the different laboratories and to try to draw general conclusions on the risks of developmental defects and genomic instability from an exposure of early embryos to moderate doses of ionizing radiation. Altogether and in the range of doses normally used in diagnostic radiology, the risk of induction of embryonic death and of congenital malformation following the irradiation of a newly fertilised egg is certainly very low when compared to the ‘spontaneous’ risks for such effects. Similarly, the risk of radiation induction of a genomic instability under such circumstances seems to be very small. However, this is not a reason to not apply some precaution principles when possible. One way of doing this is to restrict the use of higher dose examinations on all potentially pregnant women to the first ten days of their menstrual cycle when conception is very unlikely to have occurred

  8. Ion-implantation induced defects in ZnO studied by a slow positron beam

    International Nuclear Information System (INIS)

    Chen, Z.Q.; Maekawa, M.; Kawasuso, A.; Sekiguchi, T.; Suzuki, R.

    2004-01-01

    Introduction and annealing behavior of defects in Al + -implanted ZnO have been studied using an energy variable slow positron beam. Vacancy clusters are produced after Al + -implantation. With increasing ion dose above 10 14 Al + /cm 2 the implanted layer is amorphized. Heat treatment up to 600 C enhances the creation of large voids that allow the positronium formation. The large voids disappear accompanying the recrystallization process by further heat treatment above 600 C. Afterwards, implanted Al impurities are completely activated to contribute to the n-type conduction. The ZnO crystal quality is also improved after recrystallization. (orig.)

  9. Identification of defects in GaAs induced by 1 MeV electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lai, S T; Nener, B D; Faraone, L; Nassibian, A G [Western Australia Univ., Nedlands, WA (Australia); Hotchkis, M A.C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1994-12-31

    This paper shows that 1 MeV electron irradiation on n-type vapor phase epitaxial (VPE) GaAs creates three electron traps E1, E2 and EL6, and results in the splitting of the EL2 center into two levels EL2-A and EL2-B. A 15 minutes isochronal anneal results in the annihilation of the E1 and E2 traps, a reduction in EL6 trap concentration, and the return of EL2 to a single level EL2-A. A defect model is outlined which correlates with the observed results. 4 refs., 2 tabs., 3 figs.

  10. Radiation-induced defects in Czochralski-grown silicon containing carbon and germanium

    International Nuclear Information System (INIS)

    Londos, C A; Andrianakis, A; Emtsev, V V; Ohyama, H

    2009-01-01

    Formation processes of vacancy-oxygen (VO) and carbon interstitial-oxygen interstitial (C i O i ) complexes in electron-irradiated Czochralski-grown Si crystals (Cz–Si), also doped with Ge, are investigated. IR spectroscopy measurements are employed to monitor the production of these defects. In Cz–Si with carbon concentrations [C s ] up to 1 × 10 17 cm −3 and Ge concentrations [Ge] up to 1 × 10 20 cm −3 the production rate of VO defects as well as the rate of oxygen loss show a slight growth of about 10% with the increasing Ge concentration. At high concentrations of carbon [C s ] around 2 × 10 17 cm −3 the production rate of VO defects is getting larger by ∼40% in Cz–Si:Ge at Ge concentrations around 1 × 10 19 cm −3 and then at [Ge] ≈ 2 × 10 20 cm −3 this enlargement drops to ∼13%, thus approaching the values characteristic of lesser concentrations of carbon. A similar behavior against Ge concentration displays the production rate of C i O i complexes. The same trend is also observed for the rate of carbon loss, whereas the trend for the rate of oxygen loss is opposite. The behavior of Ge atoms is different at low and high concentrations of this isoelectronic impurity in Cz–Si. At low concentrations most isolated Ge atoms serve as temporary traps for vacancies preventing them from indirect annihilation with self-interstitials. At high concentrations Ge atoms are prone to form clusters. The latter ones are traps for vacancies and self-interstitials due to the strain fields, increasing the importance of indirect annihilation of intrinsic point defects. Such a model allows one to give a plausible explanation for the obtained results. A new band at 994 cm −1 seen only in irradiated Ge-doped Cz–Si is also studied. Interestingly, its annealing behavior was found to be very similar to that of VO complexes

  11. Ion-implantation induced defects in ZnO studied by a slow positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.Q.; Maekawa, M.; Kawasuso, A. [Japan Atomic Energy Research Institute, Gunma (Japan); Sekiguchi, T. [National Inst. for Materials Science, Tsukuba, Ibaraki (Japan); Suzuki, R. [National Inst. of Advanced Industrial Science and Technology, Tsukuba, Ibaraki (Japan)

    2004-07-01

    Introduction and annealing behavior of defects in Al{sup +}-implanted ZnO have been studied using an energy variable slow positron beam. Vacancy clusters are produced after Al{sup +}-implantation. With increasing ion dose above 10{sup 14} Al{sup +}/cm{sup 2} the implanted layer is amorphized. Heat treatment up to 600 C enhances the creation of large voids that allow the positronium formation. The large voids disappear accompanying the recrystallization process by further heat treatment above 600 C. Afterwards, implanted Al impurities are completely activated to contribute to the n-type conduction. The ZnO crystal quality is also improved after recrystallization. (orig.)

  12. Identification of defects in GaAs induced by 1 MeV electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lai, S.T.; Nener, B.D.; Faraone, L.; Nassibian, A.G. [Western Australia Univ., Nedlands, WA (Australia); Hotchkis, M.A.C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1993-12-31

    This paper shows that 1 MeV electron irradiation on n-type vapor phase epitaxial (VPE) GaAs creates three electron traps E1, E2 and EL6, and results in the splitting of the EL2 center into two levels EL2-A and EL2-B. A 15 minutes isochronal anneal results in the annihilation of the E1 and E2 traps, a reduction in EL6 trap concentration, and the return of EL2 to a single level EL2-A. A defect model is outlined which correlates with the observed results. 4 refs., 2 tabs., 3 figs.

  13. Spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect created in the femoral condyle using a novel double-network hydrogel.

    Science.gov (United States)

    Yokota, Masashi; Yasuda, Kazunori; Kitamura, Nobuto; Arakaki, Kazunobu; Onodera, Shin; Kurokawa, Takayuki; Gong, Jian-Ping

    2011-02-22

    Functional repair of articular osteochondral defects remains a major challenge not only in the field of knee surgery but also in tissue regeneration medicine. The purpose is to clarify whether the spontaneous hyaline cartilage regeneration can be induced in a large osteochondral defect created in the femoral condyle by means of implanting a novel double-network (DN) gel at the bottom of the defect. Twenty-five mature rabbits were used in this study. In the bilateral knees of each animal, we created an osteochondral defect having a diameter of 2.4-mm in the medial condyle. Then, in 21 rabbits, we implanted a DN gel plug into a right knee defect so that a vacant space of 1.5-mm depth (in Group I), 2.5-mm depth (in Group II), or 3.5-mm depth (in Group III) was left. In the left knee, we did not apply any treatment to the defect to obtain the control data. All the rabbits were sacrificed at 4 weeks, and the gross and histological evaluations were performed. The remaining 4 rabbits underwent the same treatment as used in Group II, and real-time PCR analysis was performed at 4 weeks. The defect in Group II was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type-2 collagen. The Wayne's gross appearance and histology scores showed that Group II was significantly greater than Group I, III, and Control (p hyaline cartilage regeneration can be induced in vivo in an osteochondral defect created in the femoral condyle by means of implanting the DN gel plug at the bottom of the defect so that an approximately 2-mm deep vacant space was intentionally left in the defect. This fact has prompted us to propose an innovative strategy without cell culture to repair osteochondral lesions in the femoral condyle.

  14. 5-AZA-2'-DEOXYCYTIDINE INDUCED CYTOTOXICITY AND LONG BONE REDUCTION DEFECTS IN THE MURINE LIMB

    Science.gov (United States)

    The antineoplastic drug 5-aza-2'-deoxycytidine (dAZA) is a DNA hypomethylating agent that can be used to induce hind limb phocomelia in the offspring of CD-1 Swiss Webster mice. Previously, our laboratory investigated the possibility that dAZA induced alterations in gene express...

  15. Genetic disassociation of autoimmunity and resistance to costimulation blockade-induced transplantation tolerance in nonobese diabetic mice.

    Science.gov (United States)

    Pearson, Todd; Markees, Thomas G; Serreze, David V; Pierce, Melissa A; Marron, Michele P; Wicker, Linda S; Peterson, Laurence B; Shultz, Leonard D; Mordes, John P; Rossini, Aldo A; Greiner, Dale L

    2003-07-01

    Curing type 1 diabetes by islet transplantation requires overcoming both allorejection and recurrent autoimmunity. This has been achieved with systemic immunosuppression, but tolerance induction would be preferable. Most islet allotransplant tolerance induction protocols have been tested in nonobese diabetic (NOD) mice, and most have failed. Failure has been attributed to the underlying autoimmunity, assuming that autoimmunity and resistance to transplantation tolerance have a common basis. Out of concern that NOD biology could be misleading in this regard, we tested the hypothesis that autoimmunity and resistance to transplantation tolerance in NOD mice are distinct phenotypes. Unexpectedly, we observed that (NOD x C57BL/6)F(1) mice, which have no diabetes, nonetheless resist prolongation of skin allografts by costimulation blockade. Further analyses revealed that the F(1) mice shared the dendritic cell maturation defects and abnormal CD4(+) T cell responses of the NOD but had lost its defects in macrophage maturation and NK cell activity. We conclude that resistance to allograft tolerance induction in the NOD mouse is not a direct consequence of overt autoimmunity and that autoimmunity and resistance to costimulation blockade-induced transplantation tolerance phenotypes in NOD mice can be dissociated genetically. The outcomes of tolerance induction protocols tested in NOD mice may not accurately predict outcomes in human subjects.

  16. Measurement and simulation of the effects of ion-induced defects on ion beam-induced charge (IBIC) measurements in Si schottky diodes

    International Nuclear Information System (INIS)

    Hearne, S.M.; Lay, M.D.H.; Jamieson, D.N.

    2004-01-01

    Full text: The Ion Beam Induced Charge (IBIC) technique is a very sensitive tool for investigating the electronic properties of semiconductor materials and devices. However, obtaining quantitative information from IBIC experiments requires an accurate model of the materials properties. The interaction of high energy ions with crystalline materials is known to create point defects within the crystal. A significant proportion of defects introduced by the interaction of the ion with the crystal are electrically active and are therefore an important consideration when undertaking an IBIC experiment. The goal of this work is to investigate the possibility of including the relevant defect parameters in computer simulations of the IBIC experiment implemented using Technology Computer Aided Design (TCAD) software. We will present the results from an IBIC study on Si Schottky diodes using 1 MeV alphas. A reduction of greater than 50% in the detected IBIC signal was observed for fluences greater than 5x10 10 He + /cm 2 . The trap parameters following ion irradiation were determined experimentally using DLTS. Comparisons between the experimental IBIC results and TCAD simulations will be discussed

  17. Evaluation of Three Bone Substitute Materials in the Treatment of Experimentally Induced Defects in Rabbit Calvaria

    Directory of Open Access Journals (Sweden)

    M. Paknejad

    2007-12-01

    Full Text Available Objective: The aim of present study was to evaluate the quality, density and thickness of newly formed bone in experimental defects treated with Combi-Pack®, Bio-Oss® and Biostite®.Materials and Methods: Eight New Zealand white rabbits were included in this randomized,blinded study. Four equal 3×6 mm bone defects were created on the frontal and parietal bones of each animal and three were immediately grafted with Bio-Oss®, Combi-Pack® and Biostite® while one was left untreated, serving as negative control. Histologic and histomorphometric analysis was performed four weeks after surgery.Results: Histomorphometric bone area and trabecular maturity was significantly higher in the Bio-Oss® and Combi-Pack® samples as compared to the Biostite® and control cases.The amount of remaining biomaterial was almost equal in the three experimental groups at the end of the study period. Neither foreign body reaction nor severe inflammation was seen in any of the specimens except for the Biostite® samples.Conclusion: It may be suggested that implantation of Bio-Oss® particles and Combi-Pack® blocks can promote bone regeneration more effectively than Biostite®.

  18. Defect induced tuning of photoluminescence property in graphitic carbon nitride nanosheets through synthesis conditions

    Energy Technology Data Exchange (ETDEWEB)

    Das, D. [School of Materials Science and Nanotechnology, Jadavpur University, Kolkata 700032 (India); Banerjee, D., E-mail: nilju82@gmail.com [School of Materials Science Engineering Indian Institute of Engineering Science and Technology, Shibpur, Howrah (India); Pahari, D. [School of Materials Science Engineering Indian Institute of Engineering Science and Technology, Shibpur, Howrah (India); Ghorai, U.K. [Department of Industrial Chemistry & Swami Vivekananda Research centre, Ramakrishna Mission Vidyamandira, Belur Math, Howrah 711202 (India); Sarkar, S.; Das, N.S. [School of Materials Science and Nanotechnology, Jadavpur University, Kolkata 700032 (India); Chattopadhyay, K.K., E-mail: kalyan_chattopadhyay@yahoo.com [School of Materials Science and Nanotechnology, Jadavpur University, Kolkata 700032 (India); Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University, Kolkata 700032 (India)

    2017-05-15

    Synthesis of layered sheet like graphitic carbon nitride by pyrolysis of urea at different temperatures has been reported. The proper phase formation has been confirmed by X-ray diffraction study whereas field emission scanning and transmission electron microscope characterized the morphology of the material. Fourier transform infrared and Raman spectroscopy revealed the presence of different bonds in the sample. Thermal gravimetric analysis has been used to study the thermal stability of the material. Energy dispersive X-ray analysis further revealed the elemental composition of carbon and nitrogen in a proper stoichiometric ratio. Excitation dependent photoluminescence spectra of the as prepared samples have been studied in detail. It has been shown that synthesis condition can tailor the amount of defects present in the synthesized samples that in turn can change the photoluminescence properties of the material. The fluorescence spectra of the as prepared samples have been used to detect copper ions present in the sample. It has also been shown that the presence of defects which is mainly N-H functional groups can change the decay characteristics of the carrier in these samples which in turn changes the PL spectra.

  19. Field induced modification of defect complexes in magnesium-doped lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Nadège; Granzow, Torsten [Department of Materials Research and Technology, Luxembourg Institute of Science and Technology, 41 rue du Brill, L-4422 Belvaux (Luxembourg); Nataf, Guillaume F., E-mail: nataf@lippmann.lu [Department of Materials Research and Technology, Luxembourg Institute of Science and Technology, 41 rue du Brill, L-4422 Belvaux (Luxembourg); CEA, DSM/IRAMIS/SPEC, F-91191 Gif-sur-Yvette Cedex (France)

    2014-12-28

    Dielectric constant, thermally stimulated depolarization currents (TSDC), and conductivity of undoped and 5% Mg-doped LiNbO{sub 3} single crystals between −100 °C and 200 °C have been investigated. A Debye-like dielectric relaxation with an activation energy of 135 meV is observed in the Mg-doped material, but not in undoped crystals. On heating this relaxation disappears near 140 °C and does not reappear after cooling. Anomalies observed in TSDC around this temperature are attributed to the motion of lithium vacancies, in agreement with conductivity measurements. It is proposed that in thermal equilibrium the electrons from the Mg{sub Li}{sup •} donors are trapped in (4Mg{sub Li}{sup •}+4V{sub Li}{sup ′}) defect complexes. High-temperature poling breaks these defect complexes. The transition of the liberated electrons between the Mg{sub Li}{sup •} donor centers and the Nb{sub Nb} forming the conduction band gives rise to the observed dielectric relaxation.

  20. Comparative evaluation of dentinal defects induced by hand files, hyflex, protaper next and one shape during canal preparation: A stereomicroscopic study

    Directory of Open Access Journals (Sweden)

    Ekta Garg

    2017-01-01

    Full Text Available Aim: This study aims to evaluate and compare the incidence of dentinal defects induced by Hand Files, HyFlex CM, ProTaper Next (PTN, and One Shape during canal preparation. Materials and Methods: One hundred and fifty extracted mandibular premolar teeth with single root canal were selected. Specimens were then divided into five groups with thirty specimens each. Group I: Specimens were prepared with hand instruments. Group II: Specimens were prepared with HyFlex CM rotary files (Coltene using a crown-down technique according to the manufacturer's instructions. Group III: Specimens were prepared with PTN rotary files (Dentsply using a crown-down technique according to the manufacturer's instructions. Group IV: Specimens were prepared with One Shape Single file rotary system (MicroMega using a crown-down technique according to the manufacturer's instructions. Group V: Specimens were used as a control and left unprepared. All roots were cut horizontally at 3, 6, and 9 mm from the apex. Sections were then viewed under stereomicroscope and dentinal defects were registered as “no defect,” “fracture,” and “other defects.” Statistical Analysis: Results of the study were subjected to Chi-square test. Results: Results were expressed as the number and percentage of defected, partially defected and roots with no defects in each groups. Conclusion: Hand files and One Shape file system caused less root defects compared to PTN and HyFlex file systems.

  1. Visualizing Angiogenesis by Multiphoton Microscopy In Vivo in Genetically Modified 3D-PLGA/nHAp Scaffold for Calvarial Critical Bone Defect Repair.

    Science.gov (United States)

    Li, Jian; Jahr, Holger; Zheng, Wei; Ren, Pei-Gen

    2017-09-07

    The reconstruction of critically sized bone defects remains a serious clinical problem because of poor angiogenesis within tissue-engineered scaffolds during repair, which gives rise to a lack of sufficient blood supply and causes necrosis of the new tissues. Rapid vascularization is a vital prerequisite for new tissue survival and integration with existing host tissue. The de novo generation of vasculature in scaffolds is one of the most important steps in making bone regeneration more efficient, allowing repairing tissue to grow into a scaffold. To tackle this problem, the genetic modification of a biomaterial scaffold is used to accelerate angiogenesis and osteogenesis. However, visualizing and tracking in vivo blood vessel formation in real-time and in three-dimensional (3D) scaffolds or new bone tissue is still an obstacle for bone tissue engineering. Multiphoton microscopy (MPM) is a novel bio-imaging modality that can acquire volumetric data from biological structures in a high-resolution and minimally-invasive manner. The objective of this study was to visualize angiogenesis with multiphoton microscopy in vivo in a genetically modified 3D-PLGA/nHAp scaffold for calvarial critical bone defect repair. PLGA/nHAp scaffolds were functionalized for the sustained delivery of a growth factor pdgf-b gene carrying lentiviral vectors (LV-pdgfb) in order to facilitate angiogenesis and to enhance bone regeneration. In a scaffold-implanted calvarial critical bone defect mouse model, the blood vessel areas (BVAs) in PHp scaffolds were significantly higher than in PH scaffolds. Additionally, the expression of pdgf-b and angiogenesis-related genes, vWF and VEGFR2, increased correspondingly. MicroCT analysis indicated that the new bone formation in the PHp group dramatically improved compared to the other groups. To our knowledge, this is the first time multiphoton microscopy was used in bone tissue-engineering to investigate angiogenesis in a 3D bio-degradable scaffold in

  2. Genetic Rescue of Mitochondrial and Skeletal Muscle Impairment in an Induced Pluripotent Stem Cells Model of Coenzyme Q10 Deficiency.

    Science.gov (United States)

    Romero-Moya, Damià; Santos-Ocaña, Carlos; Castaño, Julio; Garrabou, Gloria; Rodríguez-Gómez, José A; Ruiz-Bonilla, Vanesa; Bueno, Clara; González-Rodríguez, Patricia; Giorgetti, Alessandra; Perdiguero, Eusebio; Prieto, Cristina; Moren-Nuñez, Constanza; Fernández-Ayala, Daniel J; Victoria Cascajo, Maria; Velasco, Iván; Canals, Josep Maria; Montero, Raquel; Yubero, Delia; Jou, Cristina; López-Barneo, José; Cardellach, Francesc; Muñoz-Cánoves, Pura; Artuch, Rafael; Navas, Plácido; Menendez, Pablo

    2017-07-01

    Coenzyme Q 10 (CoQ 10 ) plays a crucial role in mitochondria as an electron carrier within the mitochondrial respiratory chain (MRC) and is an essential antioxidant. Mutations in genes responsible for CoQ 10 biosynthesis (COQ genes) cause primary CoQ 10 deficiency, a rare and heterogeneous mitochondrial disorder with no clear genotype-phenotype association, mainly affecting tissues with high-energy demand including brain and skeletal muscle (SkM). Here, we report a four-year-old girl diagnosed with minor mental retardation and lethal rhabdomyolysis harboring a heterozygous mutation (c.483G > C (E161D)) in COQ4. The patient's fibroblasts showed a decrease in [CoQ 10 ], CoQ 10 biosynthesis, MRC activity affecting complexes I/II + III, and respiration defects. Bona fide induced pluripotent stem cell (iPSCs) lines carrying the COQ4 mutation (CQ4-iPSCs) were generated, characterized and genetically edited using the CRISPR-Cas9 system (CQ4 ed -iPSCs). Extensive differentiation and metabolic assays of control-iPSCs, CQ4-iPSCs and CQ4 ed -iPSCs demonstrated a genotype association, reproducing the disease phenotype. The COQ4 mutation in iPSC was associated with CoQ 10 deficiency, metabolic dysfunction, and respiration defects. iPSC differentiation into SkM was compromised, and the resulting SkM also displayed respiration defects. Remarkably, iPSC differentiation in dopaminergic or motor neurons was unaffected. This study offers an unprecedented iPSC model recapitulating CoQ 10 deficiency-associated functional and metabolic phenotypes caused by COQ4 mutation. Stem Cells 2017;35:1687-1703. © 2017 AlphaMed Press.

  3. Transplantation of mesenchymal stem cells cultured on biomatrix support induces repairing of digestive tract defects, in animal model.

    Science.gov (United States)

    Sîrbu-Boeţi, Mirela-Patricia; Chivu, Mihaela; Pâslaru, Liliana Livia; Efrimescu, C; Herlea, V; Pecheanu, C; Moldovan, Lucia; Dragomir, Laura; Bleotu, Coralia; Ciucur, Elena; Vidulescu, Cristina; Vasilescu, Mihaela; Boicea, Anişoara; Mănoiu, S; Ionescu, M I; Popescu, I

    2009-01-01

    Transplanted mesenchymal stem cells (MSCs) appear to play a significant role in adult tissue repair. The aim of this research was to obtain MSCs enriched, three dimensional (3D) patches for transplant, and to test their ability to induce repair of iatrogenic digestive tract defects in rats. MSCs were obtained from human and rat bone marrow, cultured in vitro, and seeded in a collagen-agarose scaffold, where they showed enhanced viability and proliferation. The phenotype of the cultured cells was representative for MSCs (CD105+, CD90+, and CD34-, CD45-, CD3-, CD14-). The 3D patch was obtained by laying the MSCs enriched collagen-agarose scaffold on a human or swine aortic fragment. After excision of small portions of the rat digestive tract, the 3D patches were sutured at the edge of the defect using micro-surgical techniques. The rats were sacrificed at time-points and the regeneration of the digestive wall was investigated by immunofluorescence, light and electron microscopy. The MSCs enriched 3D patches were biocompatible, biodegradable, and prompted the regeneration of the four layers of the stomach and intestine wall in rats. Human cells were identified in the rat regenerated digestive wall as a hallmark of the transplanted MSCs. For the first time we constructed 3D patches made of cultured bone marrow MSCs, embedded into a collagen-rich biomatrix, on vascular bio-material support, and transplanted them in order to repair iatrogenic digestive tract defects. The result was a complete repair with preservation of the four layered structure of the digestive wall.

  4. Tissue- and species-specific differences in cytochrome c oxidase assembly induced by SURF1 defects

    Czech Academy of Sciences Publication Activity Database

    Kovářová, Nikola; Pecina, Petr; Nůsková, Hana; Vrbacký, Marek; Zeviani, M.; Mráček, Tomáš; Viscomi, C.; Houštěk, Josef

    2016-01-01

    Roč. 1862, č. 4 (2016), s. 705-715 ISSN 0925-4439 R&D Projects: GA ČR(CZ) GB14-36804G; GA MŠk(CZ) LL1204; GA MZd(CZ) NT12370 Institutional support: RVO:67985823 Keywords : cytochrome c oxidase * respiratory supercomplexes * leigh syndrome * SURF1−/− mouse knockout * doxycycline * pulse-chase Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.476, year: 2016

  5. The genetics of radiation-induced and sporadic osteosarcoma: a unifying theory?

    International Nuclear Information System (INIS)

    Rosemann, Michael; Kuosaite, Virginija; Nathrath, Michaela; Atkinson, Michael J.

    2002-01-01

    Cancer is a disease of the genome, with the neoplastic phenotype being passed from one cell generation to the other. Radiation-induced cancer has often been considered to represent a unique entity amongst neoplasia, with the energy deposition being held responsible for both direct (gene mutations) and indirect (bystander effects, induced instability etc) alterations to the cellular genome. However, radiogenic tumours in man and experimental animals appear to be physiologically and genetically indistinguishable from their sporadic counterparts, suggesting that the aetiologies of these two tumour types are in fact closely related. We have conducted a general screen of the genetic alterations in radiation-induced mouse osteosarcoma, a tumour that is histopathologically indistinguishable from human sporadic osteosarcoma. Comparison of the two tumour types indicates the existence of a common set of genetic changes, providing additional evidence to support the concept that the molecular pathology of radiation-induced malignancy is no different to that of sporadic cancers. (author)

  6. Laser induced recrystallisation and defects in ion implanted hexagonal SiC

    International Nuclear Information System (INIS)

    Makarov, V.V.; Tuomi, T.; Naukkarinen, K.; Luomajaervi, M.; Riihonen, M.

    1979-10-01

    SiC(6H) crystals amorphized with 14 N + -ion implantation were annealed with CO 2 laser pulses at intensities of 20 to 100 MW/cm 2 . Laser produced crystallisation due to residual ray absorption was studied by means of optical spectroscopy, 4 He + -ion backscattering spectrometry and channeling as well as Cu Kα 1 and synchrotron x-ray diffraction topography. At low laser intensities topographs revealed linear and planar defects which contributed to increased dechanneling independent of analyzing beam energy. Minimum of lattice disorder, which was in some regions of the laser impact area smaller than that obtained in thermal annealing, was attained at the peak laser intensities of about 50 MW/cm 2 . (orig.)

  7. Interaction between radiation-induced defects and lithium impurity atoms in germanium

    International Nuclear Information System (INIS)

    Vasil'eva, E.D.; Daluda, Yu.N.; Emtsev, V.V.; Kervalishvili, P.D.; Mashovets, T.V.

    1981-01-01

    The effect of gamma radiation on germanium doped with lithium in the course of extraction from a melt was studied. 60 Co γ-ray irradiation with the 6.2x10 12 cm -2 x1 -1 intensity was performed at 300 K. The temperature dependences of conductivity and Hall effect was studied in the 4.2-300 K range. It was shown that using this alloying technique lithium atoms in germanium were in a ''free'' state. It was found that on irradiation the lithium atom concentration decreases as a result of production of electrically inactive complexes with participation of lithium atoms. Besides this principal process secondary ones are observed: production of radiation donor-defects with the ionization energy Esub(c) of 80 MeV and compensating acceptors

  8. Biotin-deficient diet induces chromosome misalignment and spindle defects in mouse oocytes.

    Science.gov (United States)

    Tsuji, Ai; Nakamura, Toshinobu; Shibata, Katsumi

    2015-01-01

    Increased abnormal oocytes due to meiotic chromosome misalignment and spindle defects lead to elevated rates of infertility, miscarriage, and trisomic conceptions. Here, we investigated the effect of biotin deficiency on oocyte quality. Three-week-old female ICR mice were fed a biotin-deficient or control diet (0, 0.004 g biotin/kg diet) for 21 days. On day 22, these mouse oocytes were analyzed by immunofluorescence. Due to biotin, undernutrition increased the frequency of abnormal oocytes (the biotin deficient vs. control: 40 vs. 16%). Next, the remaining mice in the biotin-deficient group were fed a control or biotin-deficient diet from day 22 to 42. Although biotin nutritional status in the recovery group was restored, the frequency of abnormal oocytes in the recovery group was still higher than that in the control group (48 vs. 18%). Our results indicate that steady, sufficient biotin intake is required for the production of high-quality oocytes in mice.

  9. Spatially resolved positron annihilation spectroscopy on friction stir weld induced defects.

    Science.gov (United States)

    Hain, Karin; Hugenschmidt, Christoph; Pikart, Philip; Böni, Peter

    2010-04-01

    A friction stir welded (FSW) Al alloy sample was investigated by Doppler broadening spectroscopy (DBS) of the positron annihilation line. The spatially resolved defect distribution showed that the material in the joint zone becomes completely annealed during the welding process at the shoulder of the FSW tool, whereas at the tip, annealing is prevailed by the deterioration of the material due to the tool movement. This might be responsible for the increased probability of cracking in the heat affected zone of friction stir welds. Examination of a material pairing of steel S235 and the Al alloy Silafont36 by coincident Doppler broadening spectroscopy (CDBS) indicates the formation of annealed steel clusters in the Al alloy component of the sample. The clear visibility of Fe in the CDB spectra is explained by the very efficient trapping at the interface between steel cluster and bulk.

  10. Genetic background impacts vaccine-induced reduction of pneumococcal colonization

    NARCIS (Netherlands)

    Kuipers, Kirsten; Van Selm, Saskia; van Opzeeland, Fred; Langereis, Jeroen D.; Verhagen, Lilly M.; Diavatopoulos, Dimitri A.; De Jonge, Marien I.

    2017-01-01

    Vaccination has been one of the most successful strategies to reduce morbidity and mortality caused by respiratory infections. Recent evidence suggests that differences in the host genetic background and environmental factors may contribute to heterogeneity in the immune response to vaccination.

  11. Effects of plasma-induced defects on electrical characteristics of AlGaN/GaN heterostructure before and after low-temperature annealing

    International Nuclear Information System (INIS)

    Takimoto, Takuma; Takeshita, Koji; Nakamura, Seiji; Okumura, Tsugunori

    2014-01-01

    We investigated the electrical characteristics of an AlGaN/GaN heterostructure exposed to Ar plasma. In the near-surface region of the AlGaN/GaN heterostructure, we found that plasma-induced defects reduced the two-dimensional electron gas (2DEG) density and mobility at the AlGaN/GaN interface with increasing exposure time. The decrease in 2DEG density suggests that plasma-induced disordering partly extinguishes the piezo-polarization of the AlGaN layer, that the effective Schottky barrier height is increased by the introduction of negatively changed defects, or that the negatively charged defects induced during plasma exposure deactivate or compensate Si donors. In addition, we investigated the postannealing behavior of plasma-induced defects in the AlGaN/GaN heterostructure as well as in the n-GaN layer under an applied bias voltage. - Highlights: • We have investigated the electrical characteristics of the AlGaN/GaN heterostructure. • Electrons under the AlGaN/GaN interface are decreased by plasma exposure. • Post-annealing treatment with gate bias recovers the degradation caused by defects

  12. Chlamydia induces anchorage independence in 3T3 cells and detrimental cytological defects in an infection model.

    Directory of Open Access Journals (Sweden)

    Andrea E Knowlton

    Full Text Available Chlamydia are gram negative, obligate intracellular bacterial organisms with different species causing a multitude of infections in both humans and animals. Chlamydia trachomatis is the causative agent of the sexually transmitted infection (STI Chlamydia, the most commonly acquired bacterial STI in the United States. Chlamydial infections have also been epidemiologically linked to cervical cancer in women co-infected with the human papillomavirus (HPV. We have previously shown chlamydial infection results in centrosome amplification and multipolar spindle formation leading to chromosomal instability. Many studies indicate that centrosome abnormalities, spindle defects, and chromosome segregation errors can lead to cell transformation. We hypothesize that the presence of these defects within infected dividing cells identifies a possible mechanism for Chlamydia as a cofactor in cervical cancer formation. Here we demonstrate that infection with Chlamydia trachomatis is able to transform 3T3 cells in soft agar resulting in anchorage independence and increased colony formation. Additionally, we show for the first time Chlamydia infects actively replicating cells in vivo. Infection of mice with Chlamydia results in significantly increased cell proliferation within the cervix, and in evidence of cervical dysplasia. Confocal examination of these infected tissues also revealed elements of chlamydial induced chromosome instability. These results contribute to a growing body of data implicating a role for Chlamydia in cervical cancer development and suggest a possible molecular mechanism for this effect.

  13. Progesterone Prevents High-Grade Serous Ovarian Cancer by Inducing Necroptosis of p53-Defective Fallopian Tube Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Na-Yiyuan Wu

    2017-03-01

    Full Text Available High-grade serous ovarian carcinoma (HGSOC originates mainly from the fallopian tube (FT epithelium and always carries early TP53 mutations. We previously reported that tumors initiate in the FT fimbria epithelium because of apoptotic failure and the expansion of cells with DNA double-strand breaks (DSB caused by bathing of the FT epithelial cells in reactive oxygen species (ROSs and hemoglobin-rich follicular fluid (FF after ovulation. Because ovulation is frequent and HGSOC is rare, we hypothesized that luteal-phase progesterone (P4 could eliminate p53-defective FT cells. Here we show that P4, via P4 receptors (PRs, induces necroptosis in Trp53−/− mouse oviduct epithelium and in immortalized human p53-defective fimbrial epithelium through the TNF-α/RIPK1/RIPK3/MLKL pathway. Necroptosis occurs specifically at diestrus, recovers at the proestrus phase of the estrus cycle, and can be augmented with P4 supplementation. These results reveal the mechanism of the well-known ability of progesterone to prevent ovarian cancer.

  14. Point defect induced degradation of electrical properties of Ga2O3 by 10 MeV proton damage

    Science.gov (United States)

    Polyakov, A. Y.; Smirnov, N. B.; Shchemerov, I. V.; Yakimov, E. B.; Yang, Jiancheng; Ren, F.; Yang, Gwangseok; Kim, Jihyun; Kuramata, A.; Pearton, S. J.

    2018-01-01

    Deep electron and hole traps in 10 MeV proton irradiated high-quality β-Ga2O3 films grown by Hydride Vapor Phase Epitaxy (HVPE) on bulk β-Ga2O3 substrates were measured by deep level transient spectroscopy with electrical and optical injection, capacitance-voltage profiling in the dark and under monochromatic irradiation, and also electron beam induced current. Proton irradiation caused the diffusion length of charge carriers to decrease from 350-380 μm in unirradiated samples to 190 μm for a fluence of 1014 cm-2, and this was correlated with an increase in density of hole traps with optical ionization threshold energy near 2.3 eV. These defects most likely determine the recombination lifetime in HVPE β-Ga2O3 epilayers. Electron traps at Ec-0.75 eV and Ec-1.2 eV present in as-grown samples increase in the concentration after irradiation and suggest that these centers involve native point defects.

  15. Investigation of room temperature UV emission of ZnO films with different defect densities induced by laser irradiation.

    Science.gov (United States)

    Zhao, Yan; Jiang, Yijian

    2010-08-01

    We studied the room temperature UV emission of ZnO films with different defect densities which is fabricated by KrF laser irradiation process. It is shown room temperature UV photoluminescence of ZnO film is composed of contribution from free-exciton (FX) recombination and its longitudinal-optical phonon replica (FX-LO) (1LO, 2LO). With increase of the defect density, the FX emission decreased and FX-LO emission increased dramatically; and the relative strengths of FX to FX-LO emission intensities determine the peak position and intensity of UV emission. What is more, laser irradiation with moderate energy density could induce the crystalline ZnO film with very flat and smooth surface. This investigation indicates that KrF laser irradiation could effectively modulate the exciton emission and surface morphology, which is important for the application of high performance of UV emitting optoelectronic devices. Copyright 2010 Elsevier B.V. All rights reserved.

  16. High glucose-induced oxidative stress represses sirtuin deacetylase expression and increases histone acetylation leading to neural tube defects.

    Science.gov (United States)

    Yu, Jingwen; Wu, Yanqing; Yang, Peixin

    2016-05-01

    Aberrant epigenetic modifications are implicated in maternal diabetes-induced neural tube defects (NTDs). Because cellular stress plays a causal role in diabetic embryopathy, we investigated the possible role of the stress-resistant sirtuin (SIRT) family histone deacetylases. Among the seven sirtuins (SIRT1-7), pre-gestational maternal diabetes in vivo or high glucose in vitro significantly reduced the expression of SIRT 2 and SIRT6 in the embryo or neural stem cells, respectively. The down-regulation of SIRT2 and SIRT6 was reversed by superoxide dismutase 1 (SOD1) over-expression in the in vivo mouse model of diabetic embryopathy and the SOD mimetic, tempol and cell permeable SOD, PEGSOD in neural stem cell cultures. 2,3-dimethoxy-1,4-naphthoquinone (DMNQ), a superoxide generating agent, mimicked high glucose-suppressed SIRT2 and SIRT6 expression. The acetylation of histone 3 at lysine residues 56 (H3K56), H3K14, H3K9, and H3K27, putative substrates of SIRT2 and SIRT6, was increased by maternal diabetes in vivo or high glucose in vitro, and these increases were blocked by SOD1 over-expression or tempol treatment. SIRT2 or SIRT6 over-expression abrogated high glucose-suppressed SIRT2 or SIRT6 expression, and prevented the increase in acetylation of their histone substrates. The potent sirtuin activator (SRT1720) blocked high glucose-increased histone acetylation and NTD formation, whereas the combination of a pharmacological SIRT2 inhibitor and a pan SIRT inhibitor mimicked the effect of high glucose on increased histone acetylation and NTD induction. Thus, diabetes in vivo or high glucose in vitro suppresses SIRT2 and SIRT6 expression through oxidative stress, and sirtuin down-regulation-induced histone acetylation may be involved in diabetes-induced NTDs. The mechanism underlying pre-gestational diabetes-induced neural tube defects (NTDs) is still elusive. Our study unravels a new epigenetic mechanism in which maternal diabetes-induced oxidative stress represses

  17. Dependence of hydrogen-induced lattice defects and hydrogen embrittlement of cold-drawn pearlitic steels on hydrogen trap state, temperature, strain rate and hydrogen content

    International Nuclear Information System (INIS)

    Doshida, Tomoki; Takai, Kenichi

    2014-01-01

    The effects of the hydrogen state, temperature, strain rate and hydrogen content on hydrogen embrittlement susceptibility and hydrogen-induced lattice defects were evaluated for cold-drawn pearlitic steel that absorbed hydrogen in two trapping states. Firstly, tensile tests were carried out under various conditions to evaluate hydrogen embrittlement susceptibility. The results showed that peak 2 hydrogen, desorbed at temperatures above 200 °C as determined by thermal desorption analysis (TDA), had no significant effect on hydrogen embrittlement susceptibility. In contrast, hydrogen embrittlement susceptibility increased in the presence of peak 1 hydrogen, desorbed from room temperature to 200 °C as determined by TDA, at temperatures higher than −30 °C, at lower strain rates and with higher hydrogen content. Next, the same effects on hydrogen-induced lattice defects were also evaluated by TDA using hydrogen as a probe. Peak 2 hydrogen showed no significant effect on either hydrogen-induced lattice defects or hydrogen embrittlement susceptibility. It was found that hydrogen-induced lattice defects formed under the conditions where hydrogen embrittlement susceptibility increased. This relationship indicates that hydrogen embrittlement susceptibility was higher under the conditions where the formation of hydrogen-induced lattice defects tended to be enhanced. Since hydrogen-induced lattice defects formed by the interaction between hydrogen and strain were annihilated by annealing at a temperature of 200 °C, they were presumably vacancies or vacancy clusters. One of the common atomic-level changes that occur in cold-drawn pearlitic steel showing higher hydrogen embrittlement susceptibility is the formation of vacancies and vacancy clusters

  18. Study of interaction among silicon, lithium, oxygen and radiation-induced defects for radiation-hardened solar cells

    Science.gov (United States)

    Berman, P. A.

    1973-01-01

    In order to improve reliability and the useful lifetime of solar cell arrays for space use, a program was undertaken to develop radiation-hardened lithium-doped silicon solar cells. These cells were shown to be significantly more resistant to degradation by ionized particles than the presently used n-p nonlithium-doped silicon solar cells. The results of various analyses performed to develop a more complete understanding of the physics of the interaction among lithium, silicon, oxygen, and radiation-induced defects are presented. A discussion is given of those portions of the previous model of radiation damage annealing which were found to be in error and those portions which were upheld by these extensive investigations.

  19. Molecular dynamics study on the interaction of a dislocation and radiation induced defect clusters in Fcc crystals

    International Nuclear Information System (INIS)

    Hideo, Kaburaki; Tomoko, Kadoyoshi; Futoshi, Shimizu; Hajime; Kimizuka; Shiro, Jitsukawa

    2003-01-01

    Irradiation of high-energy neutrons and charged particles into solids is known to cause a significant change in mechanical properties, in particular, hardening of metals. Hardening of solids arises as a result of interactions of dislocations with irradiation induced defect clusters. Molecular dynamics method combined with the visualization method has been used to elucidate these complex pinning structures in details. In particular, we have successfully observed the transient process for the formation of a super-jog from an edge dislocation and interstitial and vacancy clusters under irradiation cascade conditions. Parallel molecular dynamics programs, called as Parallel Molecular Dynamics Stencil (PMDS), have been developed in order to perform these large scale simulations for materials simulations. The contents of the program and its parallel performance are also reported. (authors)

  20. New jump mechanisms for dumbbell and induced migration of point defects by molecular dynamics simulation

    International Nuclear Information System (INIS)

    Doan, N.V.; Pontikis, V.; Tenenbaum, A.

    1978-01-01

    The induced migration of the (100) - dumbbell is studied using the molecular dynamics simulation. Two new types of jumps are discovered for the dumbbell: first the jump takes place through an intermediate crowdion configuration (110), then the crowdion is converted into the dumbbell configuration with some other orientation. The threshold energy is found for different knocked-on directions. The dependence of the interstitial jump frequency on the incident electron energy is determined for copper. The induced interstitial migration shows a maximum value, but for an electron energy around 15 Kev. The effect of new jump mechanisms on the effective recombination volume is discussed

  1. Homozygosity mapping and targeted sanger sequencing reveal genetic defects underlying inherited retinal disease in families from pakistan.

    Directory of Open Access Journals (Sweden)

    Maleeha Maria

    Full Text Available Homozygosity mapping has facilitated the identification of the genetic causes underlying inherited diseases, particularly in consanguineous families with multiple affected individuals. This knowledge has also resulted in a mutation dataset that can be used in a cost and time effective manner to screen frequent population-specific genetic variations associated with diseases such as inherited retinal disease (IRD.We genetically screened 13 families from a cohort of 81 Pakistani IRD families diagnosed with Leber congenital amaurosis (LCA, retinitis pigmentosa (RP, congenital stationary night blindness (CSNB, or cone dystrophy (CD. We employed genome-wide single nucleotide polymorphism (SNP array analysis to identify homozygous regions shared by affected individuals and performed Sanger sequencing of IRD-associated genes located in the sizeable homozygous regions. In addition, based on population specific mutation data we performed targeted Sanger sequencing (TSS of frequent variants in AIPL1, CEP290, CRB1, GUCY2D, LCA5, RPGRIP1 and TULP1, in probands from 28 LCA families.Homozygosity mapping and Sanger sequencing of IRD-associated genes revealed the underlying mutations in 10 families. TSS revealed causative variants in three families. In these 13 families four novel mutations were identified in CNGA1, CNGB1, GUCY2D, and RPGRIP1.Homozygosity mapping and TSS revealed the underlying genetic cause in 13 IRD families, which is useful for genetic counseling as well as therapeutic interventions that are likely to become available in the near future.

  2. Induced genetic variation for aluminum and salt tolerance in rice

    International Nuclear Information System (INIS)

    Chaudhry, M.A.; Yoshida, S.; Vegara, B.S.

    1989-01-01

    Full text: MNH applied to fertilized egg cells of 'Taichung 65' led to an increase in genetic variation in the progenies. Of a M 2 population of 15,000 seedlings, 2.3% were scored tolerant to salt. Tolerant plants showed less shoot and root growth inhibition. 50 variants expressed different degrees of tolerance to Al, even up to 30 ppm. The tolerance was related to longer root development. (author)

  3. Micro-mechanisms of Surface Defects Induced on Aluminum Alloys during Plastic Deformation at Elevated Temperatures

    Science.gov (United States)

    Gali, Olufisayo A.

    Near-surface deformed layers developed on aluminum alloys significantly influence the corrosion and tribological behavior as well as reduce the surface quality of the rolled aluminum. The evolution of the near-surface microstructures induced on magnesium containing aluminum alloys during thermomechanical processing has been investigated with the aim generating an understanding of the influence of individual forming parameters on its evolution and examine the microstructure of the roll coating induced on the mating steel roll through material transfer during rolling. The micro-mechanisms related to the various features of near-surface microstructure developed during tribological conditions of the simulated hot rolling process were identified. Thermomechanical processing experiments were performed with the aid of hot rolling (operating temperature: 550 to 460 °C, 4, 10 and 20 rolling pass schedules) and hot forming (operating temperature: 350 to 545 °C, strain rate: 4 x 10-2 s-1) tribo-simulators. The surface, near-surface features and material transfer induced during the elevated temperature plastic deformation were examined and characterized employing optical interferometry, SEM/EDS, FIB and TEM. Near-surface features characterized on the rolled aluminum alloys included; cracks, fractured intermetallic particles, aluminum nano-particles, oxide decorated grain boundaries, rolled-in oxides, shingles and blisters. These features were related to various individual rolling parameters which included, the work roll roughness, which induced the formation of shingles, rolling marks and were responsible for the redistribution of surface oxide and the enhancements of the depth of the near-surface damage. The enhanced stresses and strains experienced during rolling were related to the formation and propagation of cracks, the nanocrystalline structure of the near-surface layers and aluminum nano-particles. The mechanism of the evolution of the near-surface microstructure were

  4. Radiation-induced genetic effects in germ cells of mammals

    International Nuclear Information System (INIS)

    Van Buul, P.P.W.

    1993-01-01

    The aim of the project is to gain information on the effects of ionizing radiation on germ cells of rodents and primates as measured by induced chromosomal translocations. Different aspects of the very significant interspecies differences between the mouse and the rhesus monkey (Macaca mulatta) for translocation induction in spermatogonial stem cells were studied. In addition, possible mechanisms for the well established reduced transmission of induced mouse translocations were investigated. (R.P.) 6 refs

  5. Tunable single photonic defect-mode in cholesteric liquid crystals with laser-induced local modifications of helix

    International Nuclear Information System (INIS)

    Yoshida, Hiroyuki; Lee, Chee Heng; Fujii, Akihiko; Ozaki, Masanori

    2006-01-01

    The authors demonstrate a tunable single photonic defect-mode in a single cholesteric liquid crystal material based on a structural defect introduced by local modification of the helix. An unpolymerized region of cholesteric liquid crystal acting as the defect was left between two polymerized regions via a two-photon excitation laser-lithography process. Upon polymerization, the cholesteric liquid crystal helix elongated and became thermally stable, and a single photonic defect mode was exhibited due to the contrast in the helix pitch at the defect. The defect mode showed tunability upon heating, and a 36 nm redshift was seen over a temperature range of 30 deg. C

  6. Computer stimulation of radiation-induced defects in metals irradiated with heavy ions

    International Nuclear Information System (INIS)

    Kupchishin, A.A.; Kupchishin, A.I.; Shmygaleva, T.A.

    2004-01-01

    Full text: In the work for account of defect concentration at ion irradiation the formula is proposed with use the modified cascade-probability function. It is necessary to find a real domain of result for account of cascade-probability functions (CPF) subject to losses of energy for ions depend upon a number of interactions. CPF first grows, achieving a maximum, then one decreases in the found region. The regularities of behavior of result region at change of a charge of flying particles are the following: 1. The increase of a charge z of a flying particle results in a displacement of result determination region to the left and narrowing it; 2. At the large value z, the maximum value of CPF displaces to the left as respects of h/λ already at small depths, and at the large depths the result is in a narrow region (less than 1 %, silver, gold); 3. The narrowest region of result arises at a large charge of flying particle and a target with small charge on the end of run and amounts to 100-th shares of percents

  7. dc-Hydrogen plasma induced defects in bulk n-Ge

    Energy Technology Data Exchange (ETDEWEB)

    Nyamhere, C., E-mail: cloud.nyamhere@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Venter, A.; Murape, D.M. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Auret, F.D.; Coelho, S.M.M. [Department of Physics, University of the Pretoria, Lynnwood Road, Pretoria 0002 (South Africa); Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa)

    2012-08-01

    Bulk antimony doped germanium (n-Ge) has been exposed to a dc-hydrogen plasma. Capacitance-voltage depth profiles revealed extensive near surface passivation of the shallow donors as evidenced by {approx}a 1.5 orders of magnitude reduction in the free carrier concentration up to depth of {approx}3.2 {mu}m. DLTS and Laplace-DLTS revealed a prominent electron trap 0.30 eV below the conduction (E{sub C} -0.30 eV). The concentration of this trap increased with plasma exposure time. The depth profile for this defect suggested a uniform distribution up to 1.2 {mu}m. Annealing studies show that this trap, attributed to a hydrogen-related complex, is stable up to 200 Degree-Sign C. Hole traps, or vacancy-antimony centers, common in this material after high energy particle irradiation, were not observed after plasma exposure, an indication that this process does not create Frenkel (V-I) pairs.

  8. dc-Hydrogen plasma induced defects in bulk n-Ge

    International Nuclear Information System (INIS)

    Nyamhere, C.; Venter, A.; Murape, D.M.; Auret, F.D.; Coelho, S.M.M.; Botha, J.R.

    2012-01-01

    Bulk antimony doped germanium (n-Ge) has been exposed to a dc-hydrogen plasma. Capacitance-voltage depth profiles revealed extensive near surface passivation of the shallow donors as evidenced by ∼a 1.5 orders of magnitude reduction in the free carrier concentration up to depth of ∼3.2 μm. DLTS and Laplace-DLTS revealed a prominent electron trap 0.30 eV below the conduction (E C -0.30 eV). The concentration of this trap increased with plasma exposure time. The depth profile for this defect suggested a uniform distribution up to 1.2 μm. Annealing studies show that this trap, attributed to a hydrogen-related complex, is stable up to 200 °C. Hole traps, or vacancy-antimony centers, common in this material after high energy particle irradiation, were not observed after plasma exposure, an indication that this process does not create Frenkel (V-I) pairs.

  9. SHI induced defects in chemically synthesized graphene oxide for hydrogen storage applications

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Preetam K., E-mail: preetam.nano@gmail.com; Sharma, Vinay; Rajaura, Rajveer Singh; Singh, M. [Department of Physics, University of Rajasthan, Jaipur-302004, India. (India); Srivastava, Subodh; Vijay, Y. K. [Department of Physics, University of Rajasthan, Jaipur-302004, India. (India); Department of Physics, Vivekananda Global University, Jaipur-303012, India. (India); Sharma, S. S. [Department of Physics, Govt. Women Engineering College, Ajmer-305002, India. (India)

    2016-05-06

    Graphene, due to its unique properties arising from the single carbon layer, is a potential candidate for applications in a variety of fields including sensors, photovoltaics and energy storage. The atomic structure and morphology of the carbon nanomaterials especially graphene can be tailored by energetic ionic irradiation. As graphene sheet is very stable, the surface have less reactivity as compared to the edges of the sheets. By surface modification with energetic ion-beams additional dangling bonds can be formed to enhance the surface activity of the graphene film which could be exploited in a variety of applications. In the present work, graphene oxide was synthesized by improved Hummers’ Method. The irradiation was done with Ag{sup +} ions carrying energy 100 MeV with the fluence of 3×10{sup 13}. Raman spectrum of graphene irradiated by Ag{sup +} beam shows additional disordered peaks of D´ and D+G bands. There is also a decrease in the intensity of D band. AFM images depict the increase in the surface roughness of the films. This can be attributed to the increase in the defects in the flakes and intermixing of adjacent layers by irradiation.

  10. Fusion neutron irradiation induced ordering and defect production in Cu3Au at high temperatures

    International Nuclear Information System (INIS)

    Huang, J.S.; Guinan, M.W.; Kirk, M.A.; Hahn, P.A.

    1987-08-01

    We irradiate three Cu 3 Au alloys different degrees of initial long-range order at temperatures between 300K and 434K. The resistivity of samples is monitored during irradiation and related to the long-term order parameter by the Muto relation. The results show that the ordering rate, which is proportional to the concentration of freely migrating vacancies, increases at the beginning and then decreases later with fluence. The decrease is a result of the continuous production of sinks in the form of dislocation loops. The effect of sinks on vacancy annihilation in some cases causes a reversed temperature dependence of ordering rate. The free vacancy production rate and the rate of sink production are determined using an ordering kinetics theory. The results of the 14 MeV neutron irradiations are compared to those obtained in other neutron spectra and particle irradiations. The estimated free vacancy production rate is also compared to the primary defect production rate measured at 4.2K in disordered samples

  11. The genetic effects induced by an irradiation in low doses at Drosophila melanogaster

    International Nuclear Information System (INIS)

    Zajnullin, V.G.; Taskaev, A.I.; Moskalev, A.A.; Shaposhnikov, M.V.

    2006-01-01

    The review generalizes the results obtained in researches of genetic radiation effects for Drosophila melanogaster from contamination regions near the Chernobylsk NPP. The results of laboratory investigations of low dose irradiation effects on genotype variability and lifetime of Drosophila are presented too. It supposed that the main effect of low dose irradiation is caused by the induced genetic instability against the background of which the realization of different-directed radiobiological reactions is possible [ru

  12. A study on induced current focusing potential drop (ICFPD) technique. Examination of the sizing accuracy of defects and its frequency dependence

    International Nuclear Information System (INIS)

    Kim, Hoon; Shoji, Tetsuo

    1994-01-01

    Aiming at nondestructive detection and size prediction of defects with high accuracy and resolution, an Induced Current Focusing Potential Drop (ICFPD) technique has been developed. This technique can be applied for determining the location and size of defects in components with not only simple shape such as plain surface but also more complex shape and geometry such as curved surface and dissimilar joint. This paper describes the basic principle of ICFPD and its probe development. In this ICFPD, current was induced in a conductive material by a straight induction wire, which is electrically isolated, placed on it. The benefits of this new technique compared with the conventional ACPD are: (1) Current is induced and focused only at an explorating region. (2) Applicable to defect detection by scanning the sensor probe in an explorating region. (3) Applicable to defect detection in a weld joint of austenitic stainless steel. As the results of the innovation in instrumentation and the improvement in evaluation procedure by use of suitable parameters, the existence of defects is clearly observed as the variation of potential drops, and the nondimensional parameter (V c,max. /V avg. ) has a direct correlation with crack depth. Especially, for the depth less than 5 mm, the ICFPD shows higher sensitivity than the conventional ACPD at the frequencies of 3, 10 and 30 kHz. (author)

  13. Estimation of γ irradiation induced genetic damage by Ames test

    International Nuclear Information System (INIS)

    Hosoda, Eiko

    1999-01-01

    Mutation by 60 Co γ irradiation was studied in five different histidine-requiring auxotrophs of Salmonella typhimurium. The strains TA98 (sensitive to frameshift) and TA100 (sensitive to base-pair substitution) were irradiated (10-84 Gy and 45-317 Gy, respectively) and revertants were counted. TA98 exhibited radiation-induced revertants, 2.8 fold of spontaneous revertants, although no significant increase was detected in TA100. Then, three other frameshift-sensitive strains TA1537, TA1538 and TA94 were irradiated in a dose of 61-167 Gy. Only in TA94, revertants increased 3.5 fold. Since spontaneous revertants are known to be independent of cell density, a decrease of bacterial number by γ irradiation was confirmed not to affect the induced revertants by dilution test. Thus the standard Ames Salmonella assay identified γ irradiation was confirmed not to affect the induced revertants by dilution test. Thus the standard Ames Salmonella assay identified γ irradiation as a mutagenetic agent. The mutagenicity of dinitropyrene, a mutagen widely existing in food, and dismutagenicity of boiling water insoluble fraction of Hizikia fusiforme, edible marine alga, were tested on γ induced revertant formation in TA98 and TA94. Dinitropyrene synergistically increased γ induced revertants and Hizikia insoluble fraction reduced the synergistic effect of dinitropyrene dependently on the concentration. (author)

  14. Communication: Visualization and spectroscopy of defects induced by dehydrogenation in individual silicon nanocrystals

    Science.gov (United States)

    Kislitsyn, Dmitry A.; Mills, Jon M.; Kocevski, Vancho; Chiu, Sheng-Kuei; DeBenedetti, William J. I.; Gervasi, Christian F.; Taber, Benjamen N.; Rosenfield, Ariel E.; Eriksson, Olle; Rusz, Ján; Goforth, Andrea M.; Nazin, George V.

    2016-06-01

    We present results of a scanning tunneling spectroscopy (STS) study of the impact of dehydrogenation on the electronic structures of hydrogen-passivated silicon nanocrystals (SiNCs) supported on the Au(111) surface. Gradual dehydrogenation is achieved by injecting high-energy electrons into individual SiNCs, which results, initially, in reduction of the electronic bandgap, and eventually produces midgap electronic states. We use theoretical calculations to show that the STS spectra of midgap states are consistent with the presence of silicon dangling bonds, which are found in different charge states. Our calculations also suggest that the observed initial reduction of the electronic bandgap is attributable to the SiNC surface reconstruction induced by conversion of surface dihydrides to monohydrides due to hydrogen desorption. Our results thus provide the first visualization of the SiNC electronic structure evolution induced by dehydrogenation and provide direct evidence for the existence of diverse dangling bond states on the SiNC surfaces.

  15. Recurrent candidiasis and early-onset gastric cancer in a patient with a genetically defined partial MYD88 defect

    NARCIS (Netherlands)

    Vogelaar, Ingrid P.; Ligtenberg, Marjolijn J L; van der Post, Rachel S.; de Voer, Richarda M.; Kets, C. Marleen; Jansen, Trees J G; Jacobs, Liesbeth; Schreibelt, Gerty; de Vries, I. Jolanda M; Netea, Mihai G.; Hoogerbrugge, Nicoline; Lubinski, Jan; Jakubowska, Anna; Teodorczyk, Urszula; Schackert, Hans K.; Aalfs, Cora M.; Gómez García, Encarna B.; Ranzani, Guglielmina N.; Molinaro, Valeria; van Hest, Liselotte P.; Hes, Frederik J.; Holinski-Feder, Elke; Genuardi, Maurizio; Ausems, Margreet G E M; Sijmons, Rolf H.; Wagner, Anja; van der Kolk, Lizet E.; Pinheiro, Hugo; Oliveira, Carla; Bjørnevoll, Inga; Høberg Vetti, Hildegunn; Van Krieken, J. Han J M

    2016-01-01

    Gastric cancer is caused by both genetic and environmental factors. A woman who suffered from recurrent candidiasis throughout her life developed diffuse-type gastric cancer at the age of 23 years. Using whole-exome sequencing we identified a germline homozygous missense variant in MYD88.

  16. Benfotiamine is similar to thiamine in correcting endothelial cell defects induced by high glucose.

    Science.gov (United States)

    Pomero, F; Molinar Min, A; La Selva, M; Allione, A; Molinatti, G M; Porta, M

    2001-01-01

    We investigated the hypothesis that benfotiamine, a lipophilic derivative of thiamine, affects replication delay and generation of advanced glycosylation end-products (AGE) in human umbilical vein endothelial cells cultured in the presence of high glucose. Cells were grown in physiological (5.6 mM) and high (28.0 mM) concentrations of D-glucose, with and without 150 microM thiamine or benfotiamine. Cell proliferation was measured by mitochondrial dehydrogenase activity. AGE generation after 20 days was assessed fluorimetrically. Cell replication was impaired by high glucose (72.3%+/-5.1% of that in physiological glucose, p=0.001). This was corrected by the addition of either thiamine (80.6%+/-2.4%, p=0.005) or benfotiamine (87.5%+/-8.9%, p=0.006), although it not was completely normalized (p=0.001 and p=0.008, respectively) to that in physiological glucose. Increased AGE production in high glucose (159.7%+/-38.9% of fluorescence in physiological glucose, p=0.003) was reduced by thiamine (113.2%+/-16.3%, p=0.008 vs. high glucose alone) or benfotiamine (135.6%+/-49.8%, p=0.03 vs. high glucose alone) to levels similar to those observed in physiological glucose. Benfotiamine, a derivative of thiamine with better bioavailability, corrects defective replication and increased AGE generation in endothelial cells cultured in high glucose, to a similar extent as thiamine. These effects may result from normalization of accelerated glycolysis and the consequent decrease in metabolites that are extremely active in generating nonenzymatic protein glycation. The potential role of thiamine administration in the prevention or treatment of vascular complications of diabetes deserves further investigation.

  17. The defect-induced changes of the electronic and magnetic properties in the inverse Heusler alloy Ti{sub 2}CoAl

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ying, E-mail: ychenjz@163.com [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Wu, Bo [Department of Physics, Zunyi Normal College, Zunyi 563002 (China); Yuan, Hongkuan; Feng, Yu [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Chen, Hong, E-mail: chenh@swu.edu.cn [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China)

    2015-01-15

    The first-principles calculations are performed to investigate the effect of swap, antisite and vacancy defects of three classes on the electronic and magnetic properties in the inverse Heusler alloy Ti{sub 2}CoAl of half-metallicity. Our calculations reveal that Ti(A/B)–Co and Co–Al swaps, Ti(A/B) and Al vacancy defects as well as Co{sub Ti(A)/Al} and Al{sub Ti(A)/Ti(B)} antisite defects are likely to form in a concentration as high as 12.5%. Among them, Co{sub Ti(A)} antisite is detected to be the most probable defect. It is shown that the spin polarizations of Ti{sub 2}CoAl are considerably reduced by the Ti(A/B)–Co swap and Ti(B)/Al vacancy defects, while a quite high spin polarization around 95% is observed in Co–Al swap as well as Ti(A) vacancy. Remarkably, all the likely antisite defects almost retain the half-metallic character in a concentration of 12.5% even if they have the possibility to form. However, induced by antisites, the Fermi levels shift to the edge of band gap with small peaks arising just above the Fermi level, which may destroy the half-metallicity by spin-flip excitation. - Graphical abstract: The spin polarization and formation energy of various possible defects in inverse Heusler alloy Ti{sub 2}CoAl. The triangle, star and square represent the swap, antisite and vacancy defects, respectively. - Highlights: • The swap, antisite, and vacancy defects are studied in half-metallic Ti{sub 2}CoAl. • The Co{sub Ti(A)} antisite is the most probable among the studied defects. • The antisite defects almost retain the half-metallicity. • Most of swap and vacancy defects have degraded the half-metallicity. • High spin polarizations are detected in Co–Al swap and Ti(A) vacancy defects.

  18. Annealing study of the electron-irradiation-induced defects H4 and E11 in InP: Defect transformation (H4-E11)→H4'

    International Nuclear Information System (INIS)

    Bretagnon, T.; Bastide, G.; Rouzeyre, M.

    1990-01-01

    Capacitance spectroscopy has been used to study the two dominant deep levels, H 4 and E 11 , produced in InP by low-energy electron irradiation. The annealing rates of H 4 and E 11 in the p-type material are found to be identical, as is also the dependence on free-carrier recombination and on the chemical nature of the acceptor (Cd or Zn). Recombination-enhanced annealing converts these traps to a hole trap H 4 ' , which is not detectable by conventional deep-level transient spectroscopy. Its emission and capture properties are measured and analyzed. The similarity of the creation and annealing behavior of H 4 and E 11 shows that they share a common point defect. Our results lead to the tentative identification of the defect as a phosphorous vacancy-acceptor complex and we show how this may anneal to the H 4 ' center

  19. Genetic and environmental correlates of topiramate-induced cognitive impairment

    Science.gov (United States)

    Cirulli, Elizabeth T.; Urban, Thomas J.; Marino, Susan E.; Linney, Kristen N.; Birnbaum, Angela K.; Depondt, Chantal; Attix, Deborah K.; Radtke, Rodney A.; Goldstein, David B.

    2011-01-01

    Topiramate is an antiepileptic drug that has marked, treatment-limiting side effects on specific aspects of cognitive performance in both patients and healthy volunteers. As these severe side-effects occur only in certain individuals, identifying genetic or environmental variables that influence cognitive response would be of great utility in determining whether to administer this drug to a patient. We gave an acute 100 mg oral dose of topiramate to 158 healthy volunteers and measured how the drug changed their performance on a diverse battery of cognitive tests. We found a wide range of responses to topiramate and demonstrated that not all tests in the battery were equally affected. There was no correlation between the effect of topiramate and either education level or baseline cognitive performance. Interestingly, there was up to 55-fold variation in the topiramate plasma levels of the participants. Our genome-wide association study (GWAS) of cognitive response did not reveal any genome-wide significant associations; the study was powered to find variants explaining at least 25% of the variation in cognitive response. Combining the results of this GWAS with a retrospective study of cognitive complaints in 290 epilepsy patients who received topiramate as part of their treatment also did not result in a significant association. Our results support the need for additional genetic studies of topiramate that utilize larger sample sizes. PMID:22091778

  20. Period doubling induced by thermal noise amplification in genetic circuits

    KAUST Repository

    Ruocco, G.

    2014-11-18

    Rhythms of life are dictated by oscillations, which take place in a wide rage of biological scales. In bacteria, for example, oscillations have been proven to control many fundamental processes, ranging from gene expression to cell divisions. In genetic circuits, oscillations originate from elemental block such as autorepressors and toggle switches, which produce robust and noise-free cycles with well defined frequency. In some circumstances, the oscillation period of biological functions may double, thus generating bistable behaviors whose ultimate origin is at the basis of intense investigations. Motivated by brain studies, we here study an “elemental” genetic circuit, where a simple nonlinear process interacts with a noisy environment. In the proposed system, nonlinearity naturally arises from the mechanism of cooperative stability, which regulates the concentration of a protein produced during a transcription process. In this elemental model, bistability results from the coherent amplification of environmental fluctuations due to a stochastic resonance of nonlinear origin. This suggests that the period doubling observed in many biological functions might result from the intrinsic interplay between nonlinearity and thermal noise.

  1. Production and stability of radiation-induced defects in MgAl2O4 under electronic excitation

    International Nuclear Information System (INIS)

    Yasuda, K.; Yamamoto, T.; Seki, S.; Shiiyama, K.; Matsumura, S.

    2008-01-01

    This paper investigates the formation process of radiation-induced defects in magnesium aluminate spinel and their stability using transmission electron microscopy, with emphasis on the effects of electronic excitation. Small interstitial-type dislocation loops disappeared under electron-induced electronic excitation. The elimination rate of the loops was found to be one order higher than for α-alumina. The disappearance of dislocation loops by a dissociation mechanism into isolated interstitials is discussed through analysis of the growth-and-shrink process of the loops. HARECXS analysis on cross section specimens irradiated with 350 MeV Au ions has shown the progress of cation disordering along ion tracks to be a function of electronic stopping power, (dE/dx) e . Cations were found to exchange their sites toward a random configuration. Such disordering appears from (dE/dx) e = 10 keV/nm, and increases in size with increasing (dE/dx) e to reach nearly 10 nm in diameter at 30 keV/nm, under an assumption of a fully disordered configuration

  2. Ion species dependence of the implantation-induced defects in ZnO studied by a slow positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.Q. [Department of Physics, Wuhan University (China); Maekawa, M.; Kawasuso, A.; Naramoto, H. [Advanced Science Research Center, Japan Atomic Energy Agency, Takasaki, Gunma (Japan)

    2007-07-01

    In this work, we implanted B{sup +}, O{sup +}, Al{sup +}, and P{sup +} ions into ZnO with energy of 50-380 keV and total doses of 4 x 10{sup 15} cm{sup -2} for each ion. The implantation-induced defects and their thermal recovery were studied using a slow positron beam. Vacancy clusters are produced in all the implanted samples. It is found that the thermal recovery of these vacancies induced by different ions shows much difference. In case of B{sup +} and Al{sup +}-implantation, the vacancy clusters agglomerate to much larger size and might evolve to microvoids during annealing. However, for O{sup +} and P{sup +} ions, which are heavier than B{sup +} and Al{sup +}, the vacancies show a much weaker agglomeration process. The mechanism of such difference is discussed. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Role of plasma-induced defects in the generation of 1/f noise in graphene

    Science.gov (United States)

    Cultrera, Alessandro; Callegaro, Luca; Marzano, Martina; Ortolano, Massimo; Amato, Giampiero

    2018-02-01

    It has already been reported that 1/f noise in graphene can be dominated by fluctuations of charge carrier mobility. We show here that the increasing damage induced by oxygen plasma on graphene samples result in two trends: at low doses, the magnitude of the 1/f noise increases with the dose; and at high doses, it decreases with the dose. This behaviour is interpreted in the framework of 1/f noise generated by carrier mobility fluctuations where the concentration of mobility fluctuation centers and the mean free path of the carriers are competing factors.

  4. Defective Lipoprotein Sorting Induces lolA Expression through the Rcs Stress Response Phosphorelay System

    OpenAIRE

    Tao, Kazuyuki; Narita, Shin-ichiro; Tokuda, Hajime

    2012-01-01

    The Escherichia coli LolA protein is a lipoprotein-specific chaperone that carries lipoproteins from the inner to the outer membrane. A dominant negative LolA mutant, LolA(I93C/F140C), in which both 93Ile and 140Phe are replaced by Cys, binds tightly to the lipoprotein-dedicated ABC transporter LolCDE complex on the inner membrane and therefore inhibits the detachment of outer membrane-specific lipoproteins from the inner membrane. We found that the expression of this mutant strongly induced ...

  5. Mechanical joining of materials with limited ductility: Analysis of process-induced defects

    Science.gov (United States)

    Jäckel, M.; Coppieters, S.; Hofmann, M.; Vandermeiren, N.; Landgrebe, D.; Debruyne, D.; Wallmersberger, T.; Faes, K.

    2017-10-01

    The paper shows experimental and numerical analyses of the clinching process of 6xxx series aluminum sheets in T6 condition and the self-pierce riveting process of an aluminum die casting. In the experimental investigations the damage behavior of the materials when using different tool parameters is analyzed. The focus of the numerical investigations is the damage prediction by a comparison of different damage criteria. Moreover, strength-and fatigue tests were carried out to investigate the influence of the joining process-induced damages on the strength properties of the joints.

  6. Defect-induced room temperature ferromagnetic properties of the Al-doped and undoped ZnO rod-like nanostructure

    CSIR Research Space (South Africa)

    Jule, L

    2017-07-01

    Full Text Available : 151-155 Defect-induced room temperature ferromagnetic properties of the Al-doped and undoped ZnO rod-like nanostructure Jule L Dejene F Ali AG Roro KT Mwakikunga BW ABSTRACT: In this work, electron paramagnetic resonance (EPR...

  7. Adhesion Regulating Molecule 1 Mediates HAP40 Overexpression-Induced Mitochondrial Defects

    Science.gov (United States)

    Huang, Zih-Ning; Chung, Her Min; Fang, Su-Chiung; Her, Lu-Shiun

    2017-01-01

    Striatal neuron death in Huntington's disease is associated with abnormal mitochondrial dynamics and functions. However, the mechanisms for this mitochondrial dysregulation remain elusive. Increased accumulation of Huntingtin-associated protein 40 (HAP40) has been shown to be associated with Huntington's disease. However, the link between increased HAP40 and Huntington's disease remains largely unknown. Here we show that HAP40 overexpression causes mitochondrial dysfunction and reduces cell viability in the immortalized mouse striatal neurons. HAP40-associated mitochondrial dysfunction is associated with reduction of adhesion regulating molecule 1 (ADRM1) protein. Consistently, depletion of ADRM1 by shRNAs impaired mitochondrial functions and increased mitochondrial fragmentation in mouse striatal cells. Moreover, reducing ADRM1 levels enhanced activity of fission factor dynamin-related GTPase protein 1 (Drp1) via increased phosphorylation at serine 616 of Drp1 (Drp1Ser616). Restoring ADRM1 protein levels was able to reduce HAP40-induced ROS levels and mitochondrial fragmentation and improved mitochondrial functions and cell viability. Moreover, reducing Drp1 activity by Drp1 inhibitor, Mdivi-1, ameliorates both HAP40 overexpression- and ADRM1 depletion-induced mitochondrial dysfunction. Taken together, our studies suggest that HAP40-mediated reduction of ADRM1 alters the mitochondrial fission activity and results in mitochondrial fragmentation and mitochondrial dysfunction. PMID:29209146

  8. Sodium benzoate induced developmental defects, oxidative stress and anxiety-like behaviour in zebrafish larva.

    Science.gov (United States)

    Gaur, Himanshu; Purushothaman, Srinithi; Pullaguri, Narasimha; Bhargava, Yogesh; Bhargava, Anamika

    2018-05-28

    Sodium benzoate (SB) is a common food preservative. Its FDA described safety limit is 1000 ppm. Lately, increased use of SB has prompted investigations regarding its effects on biological systems. Data regarding toxicity of SB is divergent and controversial with studies reporting both harmful and beneficial effects. Therefore, we did a systematic dose dependent toxicity study of SB using zebrafish vertebrate animal model. We also investigated oxidative stress and anxiety-like behaviour in zebrafish larva treated with SB. Our results indicate that SB induced developmental (delayed hatching), morphological (pericardial edema, yolk sac edema and tail bending), biochemical (oxidative stress) and behavioural (anxiety-like behaviour) abnormalities in developing zebrafish larva. LC 50 of SB induced toxicity was approximately 400 ppm after 48 h of SB exposure. Our study strongly supports its harmful effects on vertebrates at increasing doses. Thus, we suggest caution in the excessive use of this preservative in processed and convenience foods. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Genetic Syndromes Associated with Congenital Cardiac Defects and Ophthalmologic Changes - Systematization for Diagnosis in the Clinical Practice

    OpenAIRE

    Oliveira, Priscila H. A.; Souza, Beatriz S.; Pacheco, Eimi N.; Menegazzo, Michele S.; Corrêa, Ivan S.; Zen, Paulo R. G.; Rosa, Rafael F. M.; Cesa, Claudia C.; Pellanda, Lucia C.; Vilela, Manuel A. P.

    2018-01-01

    Abstract Background: Numerous genetic syndromes associated with heart disease and ocular manifestations have been described. However, a compilation and a summarization of these syndromes for better consultation and comparison have not been performed yet. Objective: The objective of this work is to systematize available evidence in the literature on different syndromes that may cause congenital heart diseases associated with ocular changes, focusing on the types of anatomical and functional ...

  10. Novel Genetic Variants of Sporadic Atrial Septal Defect (ASD) in a Chinese Population Identified by Whole-Exome Sequencing (WES).

    Science.gov (United States)

    Liu, Yong; Cao, Yu; Li, Yaxiong; Lei, Dongyun; Li, Lin; Hou, Zong Liu; Han, Shen; Meng, Mingyao; Shi, Jianlin; Zhang, Yayong; Wang, Yi; Niu, Zhaoyi; Xie, Yanhua; Xiao, Benshan; Wang, Yuanfei; Li, Xiao; Yang, Lirong; Wang, Wenju; Jiang, Lihong

    2018-03-05

    BACKGROUND Recently, mutations in several genes have been described to be associated with sporadic ASD, but some genetic variants remain to be identified. The aim of this study was to use whole-exome sequencing (WES) combined with bioinformatics analysis to identify novel genetic variants in cases of sporadic congenital ASD, followed by validation by Sanger sequencing. MATERIAL AND METHODS Five Han patients with secundum ASD were recruited, and their tissue samples were analyzed by WES, followed by verification by Sanger sequencing of tissue and blood samples. Further evaluation using blood samples included 452 additional patients with sporadic secundum ASD (212 male and 240 female patients) and 519 healthy subjects (252 male and 267 female subjects) for further verification by a multiplexed MassARRAY system. Bioinformatic analyses were performed to identify novel genetic variants associated with sporadic ASD. RESULTS From five patients with sporadic ASD, a total of 181,762 genomic variants in 33 exon loci, validated by Sanger sequencing, were selected and underwent MassARRAY analysis in 452 patients with ASD and 519 healthy subjects. Three loci with high mutation frequencies, the 138665410 FOXL2 gene variant, the 23862952 MYH6 gene variant, and the 71098693 HYDIN gene variant were found to be significantly associated with sporadic ASD (PASD (PASD, and supported the use of WES and bioinformatics analysis to identify disease-associated mutations.

  11. Genetic Etiology for Alcohol-Induced Cardiac Toxicity.

    Science.gov (United States)

    Ware, James S; Amor-Salamanca, Almudena; Tayal, Upasana; Govind, Risha; Serrano, Isabel; Salazar-Mendiguchía, Joel; García-Pinilla, Jose Manuel; Pascual-Figal, Domingo A; Nuñez, Julio; Guzzo-Merello, Gonzalo; Gonzalez-Vioque, Emiliano; Bardaji, Alfredo; Manito, Nicolas; López-Garrido, Miguel A; Padron-Barthe, Laura; Edwards, Elizabeth; Whiffin, Nicola; Walsh, Roddy; Buchan, Rachel J; Midwinter, William; Wilk, Alicja; Prasad, Sanjay; Pantazis, Antonis; Baski, John; O'Regan, Declan P; Alonso-Pulpon, Luis; Cook, Stuart A; Lara-Pezzi, Enrique; Barton, Paul J; Garcia-Pavia, Pablo

    2018-05-22

    Alcoholic cardiomyopathy (ACM) is defined by a dilated and impaired left ventricle due to chronic excess alcohol consumption. It is largely unknown which factors determine cardiac toxicity on exposure to alcohol. This study sought to evaluate the role of variation in cardiomyopathy-associated genes in the pathophysiology of ACM, and to examine the effects of alcohol intake and genotype on dilated cardiomyopathy (DCM) severity. The authors characterized 141 ACM cases, 716 DCM cases, and 445 healthy volunteers. The authors compared the prevalence of rare, protein-altering variants in 9 genes associated with inherited DCM. They evaluated the effect of genotype and alcohol consumption on phenotype in DCM. Variants in well-characterized DCM-causing genes were more prevalent in patients with ACM than control subjects (13.5% vs. 2.9%; p = 1.2 ×10 -5 ), but similar between patients with ACM and DCM (19.4%; p = 0.12) and with a predominant burden of titin truncating variants (TTNtv) (9.9%). Separately, we identified an interaction between TTN genotype and excess alcohol consumption in a cohort of DCM patients not meeting ACM criteria. On multivariate analysis, DCM patients with a TTNtv who consumed excess alcohol had an 8.7% absolute reduction in ejection fraction (95% confidence interval: -2.3% to -15.1%; p ACM patients. TTNtv represent a prevalent genetic predisposition for ACM, and are also associated with a worse left ventricular ejection fraction in DCM patients who consume alcohol above recommended levels. Familial evaluation and genetic testing should be considered in patients presenting with ACM. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Radiation and transposon-induced genetic damage in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Balter, H.; Griffith, C.S.; American Museum of Natural History, New York; Margulies, L.

    1992-01-01

    The interaction of X-ray-induced and transposon-induced damage was investigated in P-M hybrid dysgenesis in Drosophila melanogaster. X-ray dose-response of 330-1320 rad was monitored for sterility, fecundicity and partial X/Y chromosome loss among F 2 progeny derived from dysgenic cross of M strain females xP strain males (cross A) and its reciprocal (cross B), using a weaker and the standard Harwich P strain subline. The synergistic effect of P element activity and X-rays on sterility was observed only in cross A hybrids and the dose-response was nonlinear in hybrids derived from the strong standard reference Harwich subline, H W . This finding suggests that lesions induced by both mutator systems which produce the synergistic effects are 2-break events. Effect of increasing dose on the decline of fecundicity was synergistic, but linear, in hybrids of either subline. There was no interaction evident and thus no synergism in X/Y nondisjunction and partial Y chromosome loss measured by the loss of the B s marker alone or together with the y + marker. Interaction was detected in the loss of the y + marker alone from the X and Y chromosomes. The possible three-way interaction of X-rays (660 rad), post-replication repair deficiency and P elements mobility was assessed by measuring transmission distortion in dysgenic males derived from the Π 2 P strain. (author). 38 refs.; 5 tabs

  13. GSK3 inactivation is involved in mitochondrial complex IV defect in transforming growth factor (TGF) {beta}1-induced senescence

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Hae-Ok; Jung, Hyun-Jung; Seo, Yong-Hak; Lee, Young-Kyoung [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-721 (Korea, Republic of); Department of Molecular Science and Technology, The Graduate School, Ajou University, Suwon 443-721 (Korea, Republic of); Hwang, Sung-Chul [Department of Pulmonary and Critical Care Medicine, Ajou University School of Medicine, Suwon 443-721 (Korea, Republic of); Seong Hwang, Eun [Department of Life Science, University of Seoul, Seoul 130-743 (Korea, Republic of); Yoon, Gyesoon, E-mail: ypeace@ajou.ac.kr [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-721 (Korea, Republic of); Department of Molecular Science and Technology, The Graduate School, Ajou University, Suwon 443-721 (Korea, Republic of)

    2012-09-10

    Transforming growth factor {beta}1 (TGF {beta}1) induces Mv1Lu cell senescence by persistently producing mitochondrial reactive oxygen species (ROS) through decreased complex IV activity. Here, we investigated the molecular mechanism underlying the effect of TGF {beta}1 on mitochondrial complex IV activity. TGF {beta}1 progressively phosphorylated the negative regulatory sites of both glycogen synthase kinase 3 (GSK3) {alpha} and {beta}, corresponding well to the intracellular ROS generation profile. Pre-treatment of N-acetyl cysteine, an antioxidant, did not alter this GSK3 phosphorylation (inactivation), whereas pharmacological inhibition of GSK3 by SB415286 significantly increased mitochondrial ROS, implying that GSK3 phosphorylation is an upstream event of the ROS generation. GSK3 inhibition by SB415286 decreased complex IV activity and cellular O{sub 2} consumption rate and eventually induced senescence of Mv1Lu cell. Similar results were obtained with siRNA-mediated knockdown of GSK3. Moreover, we found that GSK3 not only exists in cytosol but also in mitochondria of Mv1Lu cell and the mitochondrial GSK3 binds complex IV subunit 6b which has no electron carrier and is topologically located in the mitochondrial intermembrane space. Involvement of subunit 6b in controlling complex IV activity and overall respiration rate was proved with siRNA-mediated knockdown of subunit 6b. Finally, TGF {beta}1 treatment decreased the binding of the subunit 6b to GSK3 and subunit 6b phosphorylation. Taken together, our results suggest that GSK3 inactivation is importantly involved in TGF {beta}1-induced complex IV defects through decreasing phosphorylation of the subunit 6b, thereby contributing to senescence-associated mitochondrial ROS generation.

  14. Possible role of mtDNA depletion and respiratory chain defects in aristolochic acid I-induced acute nephrotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Zhenzhou, E-mail: jiangcpu@yahoo.com.cn; Bao, Qingli, E-mail: bao_ql@126.com; Sun, Lixin, E-mail: slxcpu@126.com; Huang, Xin, E-mail: huangxinhx66@sohu.com; Wang, Tao, E-mail: wangtao1331@126.com; Zhang, Shuang, E-mail: cat921@sina.com; Li, Han, E-mail: hapo1101@163.com; Zhang, Luyong, E-mail: lyzhang@cpu.edu.cn

    2013-01-15

    This report describes an investigation of the pathological mechanism of acute renal failure caused by toxic tubular necrosis after treatment with aristolochic acid I (AAI) in Sprague–Dawley (SD) rats. The rats were gavaged with AAI at 0, 5, 20, or 80 mg/kg/day for 7 days. The pathologic examination of the kidneys showed severe acute tubular degenerative changes primarily affecting the proximal tubules. Supporting these results, we detected significantly increased concentrations of blood urea nitrogen (BUN) and creatinine (Cr) in the rats treated with AAI, indicating damage to the kidneys. Ultrastructural examination showed that proximal tubular mitochondria were extremely enlarged and dysmorphic with loss and disorientation of their cristae. Mitochondrial function analysis revealed that the two indicators for mitochondrial energy metabolism, the respiratory control ratio (RCR) and ATP content, were reduced in a dose-dependent manner after AAI treatment. The RCR in the presence of substrates for complex I was reduced more significantly than in the presence of substrates for complex II. In additional experiments, the activity of respiratory complex I, which is partly encoded by mitochondrial DNA (mtDNA), was more significantly impaired than that of respiratory complex II, which is completely encoded by nuclear DNA (nDNA). A real-time PCR assay revealed a marked reduction of mtDNA in the kidneys treated with AAI. Taken together, these results suggested that mtDNA depletion and respiratory chain defects play critical roles in the pathogenesis of kidney injury induced by AAI, and that the same processes might contribute to aristolochic acid-induced nephrotoxicity in humans. -- Highlights: ► AAI-induced acute renal failure in rats and the proximal tubule was the target. ► Tubular mitochondria were morphologically aberrant in ultrastructural examination. ► AAI impair mitochondrial bioenergetic function and mtDNA replication.

  15. Unsaturated fatty acids protect trophoblast cells from saturated fatty acid-induced autophagy defects.

    Science.gov (United States)

    Hong, Ye-Ji; Ahn, Hyo-Ju; Shin, Jongdae; Lee, Joon H; Kim, Jin-Hoi; Park, Hwan-Woo; Lee, Sung Ki

    2018-02-01

    Dysregulated serum fatty acids are associated with a lipotoxic placental environment, which contributes to increased pregnancy complications via altered trophoblast invasion. However, the role of saturated and unsaturated fatty acids in trophoblastic autophagy has yet to be explored. Here, we demonstrated that prolonged exposure of saturated fatty acids interferes with the invasiveness of human extravillous trophoblasts. Saturated fatty acids (but not unsaturated fatty acids) inhibited the fusion of autophagosomes and lysosomes, resulting in the formation of intracellular protein aggregates. Furthermore, when the trophoblast cells were exposed to saturated fatty acids, unsaturated fatty acids counteracted the effects of saturated fatty acids by increasing degradation of autophagic vacuoles. Saturated fatty acids reduced the levels of the matrix metalloproteinases (MMP)-2 and MMP-9, while unsaturated fatty acids maintained their levels. In conclusion, saturated fatty acids induced decreased trophoblast invasion, of which autophagy dysfunction plays a major role. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Tramadol Induced Adrenal Insufficiency: Histological, Immunohistochemical, Ultrastructural, and Biochemical Genetic Experimental Study

    OpenAIRE

    Abdelaleem, Shereen Abdelhakim; Hassan, Osama A.; Ahmed, Rasha F.; Zenhom, Nagwa M.; Rifaai, Rehab A.; El-Tahawy, Nashwa F.

    2017-01-01

    Tramadol is a synthetic, centrally acting analgesic. It is the most consumed narcotic drug that is prescribed in the world. Tramadol abuse has dramatically increased in Egypt. Long term use of tramadol can induce endocrinopathy. So, the aim of this study was to analyze the adrenal insufficiency induced by long term use of tramadol in experimental animals and also to assess its withdrawal effects through histopathological and biochemical genetic study. Forty male albino rats were used in this ...

  17. Elastic and failure response of imperfect three-dimensional metallic lattices: the role of geometric defects induced by Selective Laser Melting

    Science.gov (United States)

    Liu, Lu; Kamm, Paul; García-Moreno, Francisco; Banhart, John; Pasini, Damiano

    2017-10-01

    This paper examines three-dimensional metallic lattices with regular octet and rhombicuboctahedron units fabricated with geometric imperfections via Selective Laser Sintering. We use X-ray computed tomography to capture morphology, location, and distribution of process-induced defects with the aim of studying their role in the elastic response, damage initiation, and failure evolution under quasi-static compression. Testing results from in-situ compression tomography show that each lattice exhibits a distinct failure mechanism that is governed not only by cell topology but also by geometric defects induced by additive manufacturing. Extracted from X-ray tomography images, the statistical distributions of three sets of defects, namely strut waviness, strut thickness variation, and strut oversizing, are used to develop numerical models of statistically representative lattices with imperfect geometry. Elastic and failure responses are predicted within 10% agreement from the experimental data. In addition, a computational study is presented to shed light into the relationship between the amplitude of selected defects and the reduction of elastic properties compared to their nominal values. The evolution of failure mechanisms is also explained with respect to strut oversizing, a parameter that can critically cause failure mode transitions that are not visible in defect-free lattices.

  18. Genetic and epigenetic alterations induced by different levels of rye genome integration in wheat recipient.

    Science.gov (United States)

    Zheng, X L; Zhou, J P; Zang, L L; Tang, A T; Liu, D Q; Deng, K J; Zhang, Y

    2016-06-17

    The narrow genetic variation present in common wheat (Triticum aestivum) varieties has greatly restricted the improvement of crop yield in modern breeding systems. Alien addition lines have proven to be an effective means to broaden the genetic diversity of common wheat. Wheat-rye addition lines, which are the direct bridge materials for wheat improvement, have been wildly used to produce new wheat cultivars carrying alien rye germplasm. In this study, we investigated the genetic and epigenetic alterations in two sets of wheat-rye disomic addition lines (1R-7R) and the corresponding triticales. We used expressed sequence tag-simple sequence repeat, amplified fragment length polymorphism, and methylation-sensitive amplification polymorphism analyses to analyze the effects of the introduction of alien chromosomes (either the entire genome or sub-genome) to wheat genetic background. We found obvious and diversiform variations in the genomic primary structure, as well as alterations in the extent and pattern of the genomic DNA methylation of the recipient. Meanwhile, these results also showed that introduction of different rye chromosomes could induce different genetic and epigenetic alterations in its recipient, and the genetic background of the parents is an important factor for genomic and epigenetic variation induced by alien chromosome addition.

  19. Effect of cadmium on genetic toxicity and protection of cortex acanthopanasia radicis against genetic damage induced by cadmium

    International Nuclear Information System (INIS)

    Liu Bing; Pang Huimin; Chen Minyi

    1999-01-01

    Objective and Methods: The test of sperm aberration and micronucleus of bone marrow cells in mice were used to detect the mutagenicity of cadmium and anti-mutagenicity of Cortex Acanthopanasia Radicis (CAR) on germ cell and somatic cell. Kunming mice were divided randomly into four groups: normal saline control group (NS): MMC control group (MMC 1.0 mg/kg); Cd-mutate group (1/5 LD 50 ), 17.6 mg/kg); CAR anti-mutate group (CAR 1,2,4 g/kg + Cd). Ridit test and x 2 were used to evaluate the statistical significance of the date. Results: The experiment demonstrated that Chinese medicine CAR can significantly decrease sperm aberration and micronuclei frequencies induced by Cd (P<0.01). Conclusion: As an anti-mutagen CAR has practical value in occupational protection against genetic damage induced by Cd

  20. Genetic expression of induced rice sterility under alien-cytoplasm

    International Nuclear Information System (INIS)

    Wang Naiyuan; Cai Zhijun; Liang Kangjing; Li Yu

    2005-01-01

    Rice restorer lines were treated with 60 Co γ-ray and 4 male sterile mutants obtained with the fertility of controlled by 4 non-allelic recessive genes, respectively. Sixty combinations were made by using male sterile plants/fertile plants as male parents, and 15 different cytoplasmic substitution lines of the same cell nucleus as female parents. The result showed that F 1 spikelets were normal and fertile, and different numbers of male sterile plants were segregated in F 2 . Complete fertility genotype was not found among interactions between induced male sterile genes and alien-cytoplasms. (authors)

  1. Study on the immunological and genetic effects induced by internal exposure to radionuclides

    International Nuclear Information System (INIS)

    Zhu Shoupeng; Wang Liuyi; Luan Meiling

    1995-02-01

    The immune system is the important part of defense mechanism in organism. Studies have demonstrated the high radiosensitivity of the immunocytes to internal radionuclide exposure. It is evident that serious functional disturbances and morphological changes of immune organs are induced by internal contamination of radionuclides, including suppression of division and proliferation of immunocytes, induction of irreversible sequelae, leading to injurious effects on both central and peripheral immune organs. In order to study the consequences of the injuries of genetic material caused by internal contamination of radionuclides, researches have developed from the harmful effects on parental generation to those on the offspring. The present paper reports the study on the genetic injuries of somatic and germ cells induced by internal radionuclide exposure. Emphasis is placed on the molecular basis of radio-genetic effect and the relations of the molecular basis of DNA injury to gene mutation and chromosome aberration

  2. Using induced pluripotent stem cells to explore genetic and epigenetic variation associated with Alzheimer's disease.

    Science.gov (United States)

    Imm, Jennifer; Kerrigan, Talitha L; Jeffries, Aaron; Lunnon, Katie

    2017-11-01

    It is thought that both genetic and epigenetic variation play a role in Alzheimer's disease initiation and progression. With the advent of somatic cell reprogramming into induced pluripotent stem cells it is now possible to generate patient-derived cells that are able to more accurately model and recapitulate disease. Furthermore, by combining this with recent advances in (epi)genome editing technologies, it is possible to begin to examine the functional consequence of previously nominated genetic variants and infer epigenetic causality from recently identified epigenetic variants. In this review, we explore the role of genetic and epigenetic variation in Alzheimer's disease and how the functional relevance of nominated loci can be investigated using induced pluripotent stem cells and (epi)genome editing techniques.

  3. GENETIC INFLUENCES ON IN VTIRO PARTICULATE MATTER-INDUCED AIRWAY EPITHELIAL INJURY AND INFLAMMATORY MEDIATOR RELEASE

    Science.gov (United States)

    GENETIC INFLUENCES ON IN VITRO PARTICULATE MATTER-INDUCED AIRWAY EPITHELIAL INJURY AND INFLAMMATORY MEDIATOR RELEASE. JA Dye, JH Richards, DA Andrews, UP Kodavanti. US EPA, RTP, NC, USA.Particulate matter (PM) air pollution is capable of damaging the airway epitheli...

  4. Forward Genetics by Sequencing EMS Variation-Induced Inbred Lines

    Directory of Open Access Journals (Sweden)

    Charles Addo-Quaye

    2017-02-01

    Full Text Available In order to leverage novel sequencing techniques for cloning genes in eukaryotic organisms with complex genomes, the false positive rate of variant discovery must be controlled for by experimental design and informatics. We sequenced five lines from three pedigrees of ethyl methanesulfonate (EMS-mutagenized Sorghum bicolor, including a pedigree segregating a recessive dwarf mutant. Comparing the sequences of the lines, we were able to identify and eliminate error-prone positions. One genomic region contained EMS mutant alleles in dwarfs that were homozygous reference sequences in wild-type siblings and heterozygous in segregating families. This region contained a single nonsynonymous change that cosegregated with dwarfism in a validation population and caused a premature stop codon in the Sorghum ortholog encoding the gibberellic acid (GA biosynthetic enzyme ent-kaurene oxidase. Application of exogenous GA rescued the mutant phenotype. Our method for mapping did not require outcrossing and introduced no segregation variance. This enables work when line crossing is complicated by life history, permitting gene discovery outside of genetic models. This inverts the historical approach of first using recombination to define a locus and then sequencing genes. Our formally identical approach first sequences all the genes and then seeks cosegregation with the trait. Mutagenized lines lacking obvious phenotypic alterations are available for an extension of this approach: mapping with a known marker set in a line that is phenotypically identical to starting material for EMS mutant generation.

  5. Chromosomal Instability and Molecular Defects in Induced Pluripotent Stem Cells from Nijmegen Breakage Syndrome Patients

    Directory of Open Access Journals (Sweden)

    Tomer Halevy

    2016-08-01

    Full Text Available Nijmegen breakage syndrome (NBS results from the absence of the NBS1 protein, responsible for detection of DNA double-strand breaks (DSBs. NBS is characterized by microcephaly, growth retardation, immunodeficiency, and cancer predisposition. Here, we show successful reprogramming of NBS fibroblasts into induced pluripotent stem cells (NBS-iPSCs. Our data suggest a strong selection for karyotypically normal fibroblasts to go through the reprogramming process. NBS-iPSCs then acquire numerous chromosomal aberrations and show a delayed response to DSB induction. Furthermore, NBS-iPSCs display slower growth, mitotic inhibition, a reduced apoptotic response to stress, and abnormal cell-cycle-related gene expression. Importantly, NBS neural progenitor cells (NBS-NPCs show downregulation of neural developmental genes, which seems to be mediated by P53. Our results demonstrate the importance of NBS1 in early human development, shed light on the molecular mechanisms underlying this severe syndrome, and further expand our knowledge of the genomic stress cells experience during the reprogramming process.

  6. Genetic evidence for inducibility of recombination competence in yeast

    International Nuclear Information System (INIS)

    Fabre, F.; Roman, H.

    1977-01-01

    Recombination between unirradiated chromosomes was induced by UV or x-ray irradiation of haploids followed by a mating with heteroallelic diploids of Saccharomyces cerevisiae. The selected event of intragenic recombination did not involve the participation of the irradiated chromosome and apparently was not caused by lesions introduced into the unirradiated chromosomes by some indirect process. The results favor the idea that recombination is repressed in the majority of vegetative cells and that one effect of radiation is the release of some factor(s) necessary for recombination. Consequently, the proportion of competent cells (i.e., cells able to recombine) in the population increases. This competent state seems necessary not only for the recombinational repair of radiation-induced lesions but also, since recombinants are produced in the absence of such lesions, for spontaneous recombination. Photoreactivation of the UV-irradiated haploids led to a decrease in the production of recombinants. Hence, lesions in the DNA appear to be responsible for the induction of the recombinational ability

  7. Genetics

    Science.gov (United States)

    ... One of these is hypophosphatemic rickets , also called vitamin D -resistant rickets. CHROMOSOMAL DISORDERS In chromosomal disorders, the defect is due to either an excess or lack of the genes contained in a ...

  8. 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.)

  9. Formation of radiation-induced defects and their influence on tritium extraction from lithium silicates in out-of-pile experiments

    International Nuclear Information System (INIS)

    Abramenkovs, A.A.; Tiliks, J.E.

    1991-01-01

    Formation and properties of radiation-induced defects and radiolysis products in lithium silicates irradiated in nuclear reactor till absorbed doses 1000 MGy were studied. Radiation-induced defects (RD) and radiolysis products (RP) were qualitatively and quantitatively determinated by methods of chemical scavengers (MHS), electron-spin resonance (ESR) and optical spectroscopy. Colloidal silicon and lithium, lithium and silicon oxides, oxygen, silicon and lithium peroxides are the final products of the lithium silicates radiolysis at absorbed energy doses D abs = 1000 MGy. The concentration of radiation defects and products of radiolysis strongly depend on the temperature of irradiation, humidity, granural size. The thermostimulated extraction of tritiated water (95-98% of the released tritium is in chemical form of water) from lithium silicates ceramics proceeds according to two independent mechanisms: a) chemidesorption of surface localized tritiated water (the first order chemical reaction); b) formation of the tritium water molecules limited by triton diffusion to the near-surface layer of grains. It has been found that the concentration of radiation-induced defects considerably affects the tritium localization and releasing processes from lithium silicates. (orig.)

  10. Methotrexate Toxicity in Growing Long Bones of Young Rats: A Model for Studying Cancer Chemotherapy-Induced Bone Growth Defects in Children

    Directory of Open Access Journals (Sweden)

    Chiaming Fan

    2011-01-01

    Full Text Available The advancement and intensive use of chemotherapy in treating childhood cancers has led to a growing population of young cancer survivors who face increased bone health risks. However, the underlying mechanisms for chemotherapy-induced skeletal defects remain largely unclear. Methotrexate (MTX, the most commonly used antimetabolite in paediatric cancer treatment, is known to cause bone growth defects in children undergoing chemotherapy. Animal studies not only have confirmed the clinical observations but also have increased our understanding of the mechanisms underlying chemotherapy-induced skeletal damage. These models revealed that high-dose MTX can cause growth plate dysfunction, damage osteoprogenitor cells, suppress bone formation, and increase bone resorption and marrow adipogenesis, resulting in overall bone loss. While recent rat studies have shown that antidote folinic acid can reduce MTX damage in the growth plate and bone, future studies should investigate potential adjuvant treatments to reduce chemotherapy-induced skeletal toxicities.

  11. Kex1 protease is involved in yeast cell death induced by defective N-glycosylation, acetic acid, and chronological aging.

    Science.gov (United States)

    Hauptmann, Peter; Lehle, Ludwig

    2008-07-04

    N-glycosylation in the endoplasmic reticulum is an essential protein modification and highly conserved in evolution from yeast to humans. The key step of this pathway is the transfer of the lipid-linked core oligosaccharide to the nascent polypeptide chain, catalyzed by the oligosaccharyltransferase complex. Temperature-sensitive oligosaccharyltransferase mutants of Saccharomyces cerevisiae at the restrictive temperature, such as wbp1-1, as well as wild-type cells in the presence of the N-glycosylation inhibitor tunicamycin display typical apoptotic phenotypes like nuclear condensation, DNA fragmentation, phosphatidylserine translocation, caspase-like activity, and reactive oxygen species accumulation. Since deletion of the yeast metacaspase YCA1 did not abrogate this death pathway, we postulated a different proteolytic process to be responsible. Here, we show that Kex1 protease is involved in the programmed cell death caused by defective N-glycosylation. Its disruption decreases caspase-like activity, production of reactive oxygen species, and fragmentation of mitochondria and, conversely, improves growth and survival of cells. Moreover, we demonstrate that Kex1 contributes also to the active cell death program induced by acetic acid stress or during chronological aging, suggesting that Kex1 plays a more general role in cellular suicide of yeast.

  12. Nf1 Loss and Ras Hyperactivation in Oligodendrocytes Induce NOS-Driven Defects in Myelin and Vasculature

    Directory of Open Access Journals (Sweden)

    Debra A. Mayes

    2013-09-01

    Full Text Available Patients with neurofibromatosis type 1 (NF1 and Costello syndrome Rasopathy have behavioral deficits. In NF1 patients, these may correlate with white matter enlargement and aberrant myelin. To model these features, we induced Nf1 loss or HRas hyperactivation in mouse oligodendrocytes. Enlarged brain white matter tracts correlated with myelin decompaction, downregulation of claudin-11, and mislocalization of connexin-32. Surprisingly, non-cell-autonomous defects in perivascular astrocytes and the blood-brain barrier (BBB developed, implicating a soluble mediator. Nitric oxide (NO can disrupt tight junctions and gap junctions, and NO and NO synthases (NOS1–NOS3 were upregulated in mutant white matter. Treating mice with the NOS inhibitor NG-nitro-L-arginine methyl ester or the antioxidant N-acetyl cysteine corrected cellular phenotypes. CNP-HRasG12V mice also displayed locomotor hyperactivity, which could be rescued by antioxidant treatment. We conclude that Nf1/Ras regulates oligodendrocyte NOS and that dysregulated NO signaling in oligodendrocytes can alter the surrounding vasculature. The data suggest that antioxidants may improve some behavioral deficits in Rasopathy patients.

  13. Defects induced magnetic transition in Co doped ZnS thin films: Effects of swift heavy ion irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Shiv P., E-mail: shivpoojanbhola@gmail.com [Physics Department, University of Allahabad, Allahabad 211002 (India); Pivin, J.C. [CSNSM, IN2P3-CNRS, Batiment 108, F-91405 Orsay Campus (France); Patel, M.K; Won, Jonghan [Materials Science and Technology Division, MST-8, P.O.Box 1663, Mail Stop G755, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Chandra, Ramesh [Nanoscience Laboratory, IIC, Indian Institute of Technology, Roorkee 247667 (India); Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Kumar, Lokendra [Physics Department, University of Allahabad, Allahabad 211002 (India)

    2012-07-15

    The effect of swift heavy ions (SHI) on magnetic ordering in ZnS thin films with Co ions substituted on Zn sites is investigated. The materials have been synthesized by pulsed laser deposition on substrates held at 600 Degree-Sign C for obtaining films with wurtzite crystal structure and it showed ferromagnetic ordering up to room temperature with a paramagnetic component. 120 MeV Ag ions have been used at different fluences of 1 Multiplication-Sign 10{sup 11} ions/cm{sup 2} and 1 Multiplication-Sign 10{sup 12} ions/cm{sup 2} for SHI induced modifications. The long range correlation between paramagnetic spins on Co ions was destroyed by irradiation and the material became purely paramagnetic. The effect is ascribed to the formation of cylindrical ion tracks due to the thermal spikes resulting from electron-phonon coupling. - Highlights: Black-Right-Pointing-Pointer Effect of swift heavy ions on magnetic ordering in Co doped ZnS thin films are presented. Black-Right-Pointing-Pointer Magnetization in the pristine films is composed of ferromagnetic and paramagnetic components. Black-Right-Pointing-Pointer The films become purely paramagnetic after swift heavy ions irradiation. Black-Right-Pointing-Pointer The magnetic transition is ascribed to the formation of ion track (or cylindrical defects) due to the thermal spikes.

  14. Temperature behaviour of photoluminescence and electron-beam-induced current recombination behaviour of extended defects in solar grade silicon

    CERN Document Server

    Arguirov, T; Kittler, M; Reif, J

    2002-01-01

    The temperature dependence of D-band and band-to-band (BB) luminescence was measured in EFG samples between 80 K and room temperature for defects/dislocations presenting different amounts of contamination. The contamination density was estimated from the temperature behaviour of the electron-beam-induced current contrast, ranging between about 10 sup 4 and 10 sup 6 impurities cm sup - sup 1 dislocation length. The D1 line became already visible at room temperature but its intensity was found to exhibit a maximum at about 150 K. D2, D3 and D4 start to show up at about 250, 190 and 170 K, respectively, and increase their intensities upon lowering temperature. At room temperature the width of the D1 line is broad and becomes narrower upon lowering the temperature. D2 shows the opposite behaviour. The intensities of D1 and D2 were observed to show strong variations across the sample, whereas this was not observed for the pair D4/D3. In particular, the origin of the lines D1 and D2 is still far from being understo...

  15. Developmental programming: postnatal estradiol amplifies ovarian follicular defects induced by fetal exposure to excess testosterone and dihydrotestosterone in sheep.

    Science.gov (United States)

    Veiga-Lopez, A; Wurst, A K; Steckler, T L; Ye, W; Padmanabhan, V

    2014-04-01

    Excess of prenatal testosterone (T) induces reproductive defects including follicular persistence. Comparative studies with T and dihydrotestosterone (DHT) have suggested that follicular persistence is programmed via estrogenic actions of T. This study addresses the androgenic and estrogenic contributions in programming follicular persistence. Because humans are exposed to estrogenic environmental steroids from various sources throughout their life span and postnatal insults may also induce organizational and/or activational changes, we tested whether continuous postnatal exposure to estradiol (E) will amplify effects of prenatal steroids on ovarian function. Pregnant sheep were treated with T, DHT, E, or ED (E and DHT) from days 30 to 90 of gestation. Postnatally, a subset of the vehicle (C), T, and DHT females received an E implant. Transrectal ultrasonography was performed in the first breeding season during a synchronized cycle to monitor ovarian follicular dynamics. As expected, number of ≥8 mm follicles was higher in the T versus C group. Postnatal E reduced the number of 4 to 8 mm follicles in the DHT group. Percentage of females bearing luteinized follicles and the number of luteinized follicles differed among prenatal groups. Postnatal E increased the incidence of subluteal cycles in the prenatal T-treated females. Findings from this study confirm previous findings of divergences in programming effects of prenatal androgens and estrogens. They also indicate that some aspects of follicular dynamics are subject to postnatal modulation as well as support the existence of an extended organizational period or the need for a second insult to uncover the previously programmed event.

  16. Non-aflatoxigenicity of commercial Aspergillus oryzae strains due to genetic defects compared to aflatoxigenic Aspergillus flavus.

    Science.gov (United States)

    Tao, Lin; Chung, Soo Hyun

    2014-08-01

    Aspergillus oryzae is generally recognized as safe, but it is closely related to A. flavus in morphology and genetic characteristics. In this study, we tested the aflatoxigenicity and genetic analysis of nine commercial A. oryzae strains that were used in Korean soybean fermented products. Cultural and HPLC analyses showed that none of the commercial strains produced detectable amount of aflatoxins. According to the molecular analysis of 17 genes in the aflatoxin (AF) biosynthetic pathway, the commercial strains could be classified into three groups. The group I strains contained all the 17 AF biosynthetic genes tested in this study; the group II strains deleted nine AF biosynthetic genes and possessed eight genes, including aflG, aflI, aflK, aflL, aflM, aflO, aflP, and aflQ; the group III strains only had six AF biosynthetic genes, including aflG, aflI, aflK, aflO, aflP, and aflQ. With the reverse transcription polymerase chain reaction, the group I A. oryzae strains showed no expression of aflG, aflQ and/or aflM genes, which resulted in the lack of AF-producing ability. Group II and group III strains could not produce AF owing to the deletion of more than half of the AF biosynthetic genes. In addition, the sequence data of polyketide synthase A (pksA) of group I strains of A. oryzae showed that there were three point mutations (two silent mutations and one missense mutation) compared with aflatoxigenic A. flavus used as the positive control in this study.

  17. Birth Defects

    Science.gov (United States)

    A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of ... in the United States is born with a birth defect. A birth defect may affect how the ...

  18. Heavy ion induced genetic effects in mammalian cells. Final report

    International Nuclear Information System (INIS)

    Kiefer, J.; Brend'amour, M.; Casares, A.; Egenolf, R.; Gutermuth, F.; Ikpeme, S.E.; Koch, S.; Kost, M.; Loebrich, M.; Pross, H.D.; Russmann, C.; Schmidt, P.; Schneider, E.; Stoll, U.; Weber, K.J.

    2001-01-01

    DNA double-strand breaks (DSBs) are generally assumed to be the most relevant initial event producing radiation-induced cellular lethality, as well as mutations and transformations. The dependence of their formation on radiation quality has been recently reviewed. Contrary to earlier observations there seems to be now agreement that the RBE does not increase above unity with increasing LET in mammalian cells when conventional techniques are applied which are not able to resolve smaller fragments. If they are, however, included in the analysis maximum RBE values around 2 are obtained. The situation is different with yeast: An increased effectiveness for DSB induction has been reported with alpha particles, as well as for heavy ions. This may be due to differences in methods or to chromosomal structure, as discussed in more detail in this paper. DSB induction was measured for a LET range of 100 to 11500 keV/? m in yeast cells using pulsed field gel electrophoresis. Under the conditions applied the chromosomes of the yeast cells could be separated according to size allowing the direct quantification of the DSB yield by measuring the intensity of the largest chromosomes. The results demonstrate clearly that DSB induction in yeast depends on radiation quality. The derived cross-sections for DSB induction were also compared to those for cell inactivation determined in parallel experiments under identical irradiation conditions. (orig.)

  19. Prevalence of symptomatic and silent stress-induced perfusion defects in diabetic patients with suspected coronary artery disease referred for myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Prior, John O.; Calcagni, Maria-Lucia; Bischof Delaloye, Angelika; Monbaron, David; Ruiz, Juan; Koehli, Melanie

    2005-01-01

    Silent myocardial ischaemia - as evaluated by stress-induced perfusion defects on myocardial perfusion scintigraphy (MPS) in patients without a history of chest pain - is frequent in diabetes and is associated with increased rates of cardiovascular events. Its prevalence has been determined in asymptomatic diabetic patients, but remains largely unknown in diabetic patients with suspected coronary artery disease (CAD) in the clinical setting. In this study we therefore sought (a) to determine the prevalence of symptomatic and silent perfusion defects in diabetic patients with suspected CAD and (b) to characterise the eventual predictors of abnormal perfusion. The patient population comprised 133 consecutive diabetic patients with suspected CAD who had been referred for MPS. Studies were performed with exercise (41%) or pharmacological stress testing (1-day protocol, 99m Tc-sestamibi, 201 Tl or both). We used semi-quantitative analysis (20-segment polar maps) to derive the summed stress score (SSS) and the summed difference score (SDS). Abnormal MPS (SSS≥4) was observed in 49 (37%) patients (SSS=4.9±8.4, SDS=2.4±4.7), reversible perfusion defects (SDS≥2) in 40 (30%) patients [SSS=13.3±10.9; SDS=8.0±5.6; 20% moderate to severe (SDS>4), 7% multivessel] and fixed defects in 21 (16%) patients. Results were comparable between patients with and patients without a history of chest pain. Of 75 patients without a history of chest pain, 23 (31%, 95% CI=21-42%) presented reversible defects (SSS=13.9±11.3; SDS=7.4±1.2), indicative of silent ischaemia. Reversible defects were associated with inducible ST segment depression during MPS stress (odds ratio (OR)=3.2, p<0.01). Fixed defects were associated with erectile dysfunction in males (OR=3.7, p=0.02) and lower aspirin use (OR=0.25, p=0.02). Silent stress-induced perfusion defects occurred in 31% of the patients, a rate similar to that in patients with a history of chest pain. MPS could identify these patients with a

  20. Prevalence of symptomatic and silent stress-induced perfusion defects in diabetic patients with suspected coronary artery disease referred for myocardial perfusion scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Prior, John O.; Calcagni, Maria-Lucia; Bischof Delaloye, Angelika [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Nuclear Medicine, Lausanne (Switzerland); Monbaron, David; Ruiz, Juan [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Endocrinology, Diabetology and Metabolism, Lausanne (Switzerland); Koehli, Melanie [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Nuclear Medicine, Lausanne (Switzerland); Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Endocrinology, Diabetology and Metabolism, Lausanne (Switzerland)

    2005-01-01

    Silent myocardial ischaemia - as evaluated by stress-induced perfusion defects on myocardial perfusion scintigraphy (MPS) in patients without a history of chest pain - is frequent in diabetes and is associated with increased rates of cardiovascular events. Its prevalence has been determined in asymptomatic diabetic patients, but remains largely unknown in diabetic patients with suspected coronary artery disease (CAD) in the clinical setting. In this study we therefore sought (a) to determine the prevalence of symptomatic and silent perfusion defects in diabetic patients with suspected CAD and (b) to characterise the eventual predictors of abnormal perfusion. The patient population comprised 133 consecutive diabetic patients with suspected CAD who had been referred for MPS. Studies were performed with exercise (41%) or pharmacological stress testing (1-day protocol, {sup 99m}Tc-sestamibi, {sup 201}Tl or both). We used semi-quantitative analysis (20-segment polar maps) to derive the summed stress score (SSS) and the summed difference score (SDS). Abnormal MPS (SSS{>=}4) was observed in 49 (37%) patients (SSS=4.9{+-}8.4, SDS=2.4{+-}4.7), reversible perfusion defects (SDS{>=}2) in 40 (30%) patients [SSS=13.3{+-}10.9; SDS=8.0{+-}5.6; 20% moderate to severe (SDS>4), 7% multivessel] and fixed defects in 21 (16%) patients. Results were comparable between patients with and patients without a history of chest pain. Of 75 patients without a history of chest pain, 23 (31%, 95% CI=21-42%) presented reversible defects (SSS=13.9{+-}11.3; SDS=7.4{+-}1.2), indicative of silent ischaemia. Reversible defects were associated with inducible ST segment depression during MPS stress (odds ratio (OR)=3.2, p<0.01). Fixed defects were associated with erectile dysfunction in males (OR=3.7, p=0.02) and lower aspirin use (OR=0.25, p=0.02). Silent stress-induced perfusion defects occurred in 31% of the patients, a rate similar to that in patients with a history of chest pain. MPS could identify

  1. Matrix-induced autologous chondrocyte implantation for the treatment of chondral defects of the knees in Chinese patients

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    Zhang ZW

    2014-12-01

    Full Text Available Zhongwen Zhang,1 Xin Zhong,2 Huiru Ji,1 Zibin Tang,1 Jianpeng Bai,1 Minmin Yao,1 Jianlei Hou,1 Minghao Zheng,3 David J Wood,3 Jiazhi Sun,4 Shu-Feng Zhou,4,5 Aibing Liu6 1Department of Orthopedics, General Hospital of Chinese People’s Armed Police Forces (CAPF, Beijing; 2Department of MRI Center, General Hospital of CAPF, Beijing, People’s Republic of China; 3Center for Orthopedic Research, School of Surgery and Pathology, University of Western Australia, Perth, Western Australia, Australia; 4Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA; 5Guizhou Provincial Key Laboratory for Regenerative Medicine, Stem Cell and Tissue Engineering Research Center and Sino–US Joint Laboratory for Medical Sciences, Guiyang Medical University, Guiyang, Guizhou; 6Medical Research Center, General Hospital of Chinese People’s Armed Police Forces (CAPF, Beijing, People’s Republic of China Abstract: Articular cartilage injury is the most common type of damage seen in clinical orthopedic practice. The matrix-induced autologous chondrocyte implant (MACI was developed to repair articular cartilage with an advance on the autologous chondrocyte implant procedure. This study aimed to evaluate whether MACI is a safe and efficacious cartilage repair treatment for patients with knee cartilage lesions. The primary outcomes were the Knee Injury and Osteoarthritis Outcome Score (KOOS domains and magnetic resonance imaging (MRI results, compared between baseline and postoperative months 3, 6, 12, and 24. A total of 15 patients (20 knees, with an average age of 33.9 years, had a mean defect size of 4.01 cm2. By 6-month follow-up, KOOS results demonstrated significant improvements in symptoms and knee-related quality of life. MRI showed significant improvements in four individual graft scoring parameters at 24 months postoperatively. At 24 months, 90% of MACI grafts had filled completely and 10% had good

  2. Genome-wide association mapping in dogs enables identification of the homeobox gene, NKX2-8, as a genetic component of neural tube defects in humans.

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    Noa Safra

    Full Text Available Neural tube defects (NTDs is a general term for central nervous system malformations secondary to a failure of closure or development of the neural tube. The resulting pathologies may involve the brain, spinal cord and/or vertebral column, in addition to associated structures such as soft tissue or skin. The condition is reported among the more common birth defects in humans, leading to significant infant morbidity and mortality. The etiology remains poorly understood but genetic, nutritional, environmental factors, or a combination of these, are known to play a role in the development of NTDs. The variable conditions associated with NTDs occur naturally in dogs, and have been previously reported in the Weimaraner breed. Taking advantage of the strong linkage-disequilibrium within dog breeds we performed genome-wide association analysis and mapped a genomic region for spinal dysraphism, a presumed NTD, using 4 affected and 96 unaffected Weimaraners. The associated region on canine chromosome 8 (pgenome  =3.0 × 10(-5, after 100,000 permutations, encodes 18 genes, including NKX2-8, a homeobox gene which is expressed in the developing neural tube. Sequencing NKX2-8 in affected Weimaraners revealed a G to AA frameshift mutation within exon 2 of the gene, resulting in a premature stop codon that is predicted to produce a truncated protein. The exons of NKX2-8 were sequenced in human patients with spina bifida and rare variants (rs61755040 and rs10135525 were found to be significantly over-represented (p=0.036. This is the first documentation of a potential role for NKX2-8 in the etiology of NTDs, made possible by investigating the molecular basis of naturally occurring mutations in dogs.

  3. The effect of 3D nanofibrous scaffolds on the chondrogenesis of induced pluripotent stem cells and their application in restoration of cartilage defects.

    Science.gov (United States)

    Liu, Ji; Nie, Huarong; Xu, Zhengliang; Niu, Xin; Guo, Shangchun; Yin, Junhui; Guo, Fei; Li, Gang; Wang, Yang; Zhang, Changqing

    2014-01-01

    The discovery of induced pluripotent stem cells (iPSCs) rendered the reprogramming of terminally differentiated cells to primary stem cells with pluripotency possible and provided potential for the regeneration and restoration of cartilage defect. Chondrogenic differentiation of iPSCs is crucial for their application in cartilage tissue engineering. In this study we investigated the effect of 3D nanofibrous scaffolds on the chondrogenesis of iPSCs and articular cartilage defect restoration. Super-hydrophilic and durable mechanic polycaprolactone (PCL)/gelatin scaffolds were fabricated using two separate electrospinning processes. The morphological structure and mechanical properties of the scaffolds were characterized. The chondrogenesis of the iPSCs in vitro and the restoration of the cartilage defect was investigated using scanning electron microscopy (SEM), the Cell Counting Kit-8 (CCK-8), histological observation, RT-qPCR, and western blot analysis. iPSCs on the scaffolds expressed higher levels of chondrogenic markers than the control group. In an animal model, cartilage defects implanted with the scaffold-cell complex exhibited an enhanced gross appearance and histological improvements, higher cartilage-specific gene expression and protein levels, as well as subchondral bone regeneration. Therefore, we showed scaffolds with a 3D nanofibrous structure enhanced the chondrogenesis of iPSCs and that iPSC-containing scaffolds improved the restoration of cartilage defects to a greater degree than did scaffolds alone in vivo.

  4. The effect of 3D nanofibrous scaffolds on the chondrogenesis of induced pluripotent stem cells and their application in restoration of cartilage defects.

    Directory of Open Access Journals (Sweden)

    Ji Liu

    Full Text Available The discovery of induced pluripotent stem cells (iPSCs rendered the reprogramming of terminally differentiated cells to primary stem cells with pluripotency possible and provided potential for the regeneration and restoration of cartilage defect. Chondrogenic differentiation of iPSCs is crucial for their application in cartilage tissue engineering. In this study we investigated the effect of 3D nanofibrous scaffolds on the chondrogenesis of iPSCs and articular cartilage defect restoration. Super-hydrophilic and durable mechanic polycaprolactone (PCL/gelatin scaffolds were fabricated using two separate electrospinning processes. The morphological structure and mechanical properties of the scaffolds were characterized. The chondrogenesis of the iPSCs in vitro and the restoration of the cartilage defect was investigated using scanning electron microscopy (SEM, the Cell Counting Kit-8 (CCK-8, histological observation, RT-qPCR, and western blot analysis. iPSCs on the scaffolds expressed higher levels of chondrogenic markers than the control group. In an animal model, cartilage defects implanted with the scaffold-cell complex exhibited an enhanced gross appearance and histological improvements, higher cartilage-specific gene expression and protein levels, as well as subchondral bone regeneration. Therefore, we showed scaffolds with a 3D nanofibrous structure enhanced the chondrogenesis of iPSCs and that iPSC-containing scaffolds improved the restoration of cartilage defects to a greater degree than did scaffolds alone in vivo.

  5. Preferential repair of ionizing radiation-induced damage in the transcribed strand of an active human gene is defective in Cockayne syndrome

    International Nuclear Information System (INIS)

    Leadon, S.A.; Copper, P.K.

    1993-01-01

    Cells from patients with Cockayne syndrome (CS), which are sensitive to killing by UV although overall damage removal appears normal, are specifically defective in repair of UV damage in actively transcribe genes. Because several CS strains display cross-sensitivity to killing by ionizing radiation, the authors examined whether ionizing radiation-induced damage in active genes is preferentially repaired by normal cells and whether the radiosensitivity of CS cells can be explained by a defect in this process. They found that ionizing radiation-induced damage was repaired more rapidly in the transcriptionally active metallothionein IIA (MTIIA) gene than in the inactive MTIIB gene or in the genome overall in normal cells as a result of faster repair on the transcribed strand of MTIIA. Cells of the radiosensitive CS strain CS1AN are completely defective in this strand-selective repair of ionizing radiation-induced damage, although their overall repair rate appears normal. CS3BE cells, which are intermediate in radiosensitivity, do exhibit more rapid repair of the transcribed strand but at a reduced rate compared to normal cells. Xeroderma pigmentosum complementation group A cells, which are hypersensitive to UV light because of a defect in the nucleotide excision repair pathway but do not show increased sensitivity to ionizing radiation, preferentially repair ionizing radiation-induced damage on the transcribed strand of MTIIA. Thus, the ability to rapidly repair ionizing radiation-induced damage in actively transcribing genes correlates with cell survival. The results extend the generality of preferential repair in active genes to include damage other than bulky lesions

  6. Evidence of a genetic instability induced by the incorporation of a DNA precursor marked with tritium

    International Nuclear Information System (INIS)

    Saintigny, Y.; Laurent, D.; Lahayel, J.B.; Roche, St.; Meynard, D.; Lopez, B.S.

    2009-01-01

    The authors report a molecular geno-toxicology investigation which allowed molecular events induced par intracellular incorporation of tritium to be studied, and the genetic instability resulting from a chronic exposure even at low dose to be analysed. For this purpose, they developed cell models (hamster tumorous cells and human fibroblasts) in which they know how to incorporate given quantities of marked nucleotides in the DNA. They show that the incorporation of tritium, even with doses which are said to be non toxic, causes a prolonged exposure of the cell to a genotoxic stress, and maybe a genetic instability due to a too great number of recombination events

  7. Radiation-induced defect-formation in lithium hydride and deuteride monocrystals. [Electron and X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Pustovarov, V.A.; Betenekova, T.A.; Zav' yalov, N.A.; Cholakh, S.O. (Ural' skij Politekhnicheskij Inst., Sverdlovsk (USSR))

    1983-08-01

    Methods of stationary and pulse absorption spectroscopy were used to investigate into processes of formation and decay of radiation defects in cubic LiH and LiD crystals. F- and V-centers form at low temperatures during crystal irradiation by photons, creating excitons selectively, accelerator electrons, X-ray radiation. Analysis of possible mechanisms of defect formation shows that radiation defect formation in LiH is based on radiationless exciton decay. It is shown that efficiency of F- and V-centers generation in pure and impure crystals in 80-298 K range is the same. Exciton decay with formation of Frenkel radiation defects in pure LiH and LiD crystals takes place, probably, in regular crystal lattice points. Process of radiation defect formation as a result of near activator exciton decay takes place in impure LiH-Na, LiD-Na crystals.

  8. Value of transmission electron microscopy for primary ciliary dyskinesia diagnosis in the era of molecular medicine: Genetic defects with normal and non-diagnostic ciliary ultrastructure.

    Science.gov (United States)

    Shapiro, Adam J; Leigh, Margaret W

    2017-01-01

    Primary ciliary dyskinesia (PCD) is a genetic disorder causing chronic oto-sino-pulmonary disease. No single diagnostic test will detect all PCD cases. Transmission electron microscopy (TEM) of respiratory cilia was previously considered the gold standard diagnostic test for PCD, but 30% of all PCD cases have either normal ciliary ultrastructure or subtle changes which are non-diagnostic. These cases are identified through alternate diagnostic tests, including nasal nitric oxide measurement, high-speed videomicroscopy analysis, immunofluorescent staining of axonemal proteins, and/or mutation analysis of various PCD causing genes. Autosomal recessive mutations in DNAH11 and HYDIN produce normal TEM ciliary ultrastructure, while mutations in genes encoding for radial spoke head proteins result in some cross-sections with non-diagnostic alterations in the central apparatus interspersed with normal ciliary cross-sections. Mutations in nexin link and dynein regulatory complex genes lead to a collection of different ciliary ultrastructures; mutations in CCDC65, CCDC164, and GAS8 produce normal ciliary ultrastructure, while mutations in CCDC39 and CCDC40 cause absent inner dynein arms and microtubule disorganization in some ciliary cross-sections. Mutations in CCNO and MCIDAS cause near complete absence of respiratory cilia due to defects in generation of multiple cellular basal bodies; however, the scant cilia generated may have normal ultrastructure. Lastly, a syndromic form of PCD with retinal degeneration results in normal ciliary ultrastructure through mutations in the RPGR gene. Clinicians must be aware of these genetic causes of PCD resulting in non-diagnostic TEM ciliary ultrastructure and refrain from using TEM of respiratory cilia as a test to rule out PCD.

  9. Thymidine kinase 2 deficiency-induced mtDNA depletion in mouse liver leads to defect β-oxidation.

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    Xiaoshan Zhou

    Full Text Available Thymidine kinase 2 (TK2 deficiency in humans causes mitochondrial DNA (mtDNA depletion syndrome. To study the molecular mechanisms underlying the disease and search for treatment options, we previously generated and described a TK2 deficient mouse strain (TK2(-/- that progressively loses its mtDNA. The TK2(-/- mouse model displays symptoms similar to humans harboring TK2 deficient infantile fatal encephalomyopathy. Here, we have studied the TK2(-/- mouse model to clarify the pathological role of progressive mtDNA depletion in liver for the severe outcome of TK2 deficiency. We observed that a gradual depletion of mtDNA in the liver of the TK2(-/- mice was accompanied by increasingly hypertrophic mitochondria and accumulation of fat vesicles in the liver cells. The levels of cholesterol and nonesterified fatty acids were elevated and there was accumulation of long chain acylcarnitines in plasma of the TK2(-/- mice. In mice with hepatic mtDNA levels below 20%, the blood sugar and the ketone levels dropped. These mice also exhibited reduced mitochondrial β-oxidation due to decreased transport of long chain acylcarnitines into the mitochondria. The gradual loss of mtDNA in the liver of the TK2(-/- mice causes impaired mitochondrial function that leads to defect β-oxidation and, as a result, insufficient production of ketone bodies and glucose. This study provides insight into the mechanism of encephalomyopathy caused by TK2 deficiency-induced mtDNA depletion that may be used to explore novel therapeutic strategies.

  10. Thymidine kinase 2 deficiency-induced mtDNA depletion in mouse liver leads to defect β-oxidation.

    Science.gov (United States)

    Zhou, Xiaoshan; Kannisto, Kristina; Curbo, Sophie; von Döbeln, Ulrika; Hultenby, Kjell; Isetun, Sindra; Gåfvels, Mats; Karlsson, Anna

    2013-01-01

    Thymidine kinase 2 (TK2) deficiency in humans causes mitochondrial DNA (mtDNA) depletion syndrome. To study the molecular mechanisms underlying the disease and search for treatment options, we previously generated and described a TK2 deficient mouse strain (TK2(-/-)) that progressively loses its mtDNA. The TK2(-/-) mouse model displays symptoms similar to humans harboring TK2 deficient infantile fatal encephalomyopathy. Here, we have studied the TK2(-/-) mouse model to clarify the pathological role of progressive mtDNA depletion in liver for the severe outcome of TK2 deficiency. We observed that a gradual depletion of mtDNA in the liver of the TK2(-/-) mice was accompanied by increasingly hypertrophic mitochondria and accumulation of fat vesicles in the liver cells. The levels of cholesterol and nonesterified fatty acids were elevated and there was accumulation of long chain acylcarnitines in plasma of the TK2(-/-) mice. In mice with hepatic mtDNA levels below 20%, the blood sugar and the ketone levels dropped. These mice also exhibited reduced mitochondrial β-oxidation due to decreased transport of long chain acylcarnitines into the mitochondria. The gradual loss of mtDNA in the liver of the TK2(-/-) mice causes impaired mitochondrial function that leads to defect β-oxidation and, as a result, insufficient production of ketone bodies and glucose. This study provides insight into the mechanism of encephalomyopathy caused by TK2 deficiency-induced mtDNA depletion that may be used to explore novel therapeutic strategies.

  11. Cadmium-induced neural tube defects and fetal growth restriction: Association with disturbance of placental folate transport

    International Nuclear Information System (INIS)

    Zhang, Gui-Bin; Wang, Hua; Hu, Jun; Guo, Min-Yin; Wang, Ying; Zhou, Yan; Yu, Zhen; Fu, Lin; Chen, Yuan-Hua; Xu, De-Xiang

    2016-01-01

    Previous studies found that maternal Cd exposure on gestational day (GD)9 caused forelimb ectrodactyly and tail deformity, the characteristic malformations. The aim of the present study was to investigate whether maternal Cd exposure on GD8 induces fetal neural tube defects (NTDs). Pregnant mice were intraperitoneally injected with CdCl 2 (2.5 or 5.0 mg/kg) on GD8. Neither forelimb ectrodactyly nor tail deformity was observed in mice injected with CdCl 2 on GD8. Instead, maternal Cd exposure on GD8 resulted in the incidence of NTDs. Moreover, maternal Cd exposure on GD8 resulted in fetal growth restriction. In addition, maternal Cd exposure on GD8 reduced placental weight and diameter. The internal space of maternal and fetal blood vessels in the labyrinth layer was decreased in the placentas of mice treated with CdCl 2 . Additional experiment showed that placental PCFT protein and mRNA, a critical folate transporter, was persistently decreased when dams were injected with CdCl 2 on GD8. Correspondingly, embryonic folate content was markedly decreased in mice injected with CdCl 2 on GD8, whereas Cd had little effect on folate content in maternal serum. Taken together, these results suggest that maternal Cd exposure during organogenesis disturbs transport of folate from maternal circulation to the fetuses through down-regulating placental folate transporters. - Highlights: • Maternal Cd exposure during organogenesis causes NTDs and FGR. • Maternal Cd exposure during organogenesis impairs placental development. • Cd disturbs transport of folate by down-regulating placental folate transporters.

  12. Cadmium-induced neural tube defects and fetal growth restriction: Association with disturbance of placental folate transport

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Gui-Bin; Wang, Hua, E-mail: wanghuadev@126.com; Hu, Jun; Guo, Min-Yin; Wang, Ying; Zhou, Yan; Yu, Zhen; Fu, Lin; Chen, Yuan-Hua; Xu, De-Xiang, E-mail: xudex@126.com

    2016-09-01

    Previous studies found that maternal Cd exposure on gestational day (GD)9 caused forelimb ectrodactyly and tail deformity, the characteristic malformations. The aim of the present study was to investigate whether maternal Cd exposure on GD8 induces fetal neural tube defects (NTDs). Pregnant mice were intraperitoneally injected with CdCl{sub 2} (2.5 or 5.0 mg/kg) on GD8. Neither forelimb ectrodactyly nor tail deformity was observed in mice injected with CdCl{sub 2} on GD8. Instead, maternal Cd exposure on GD8 resulted in the incidence of NTDs. Moreover, maternal Cd exposure on GD8 resulted in fetal growth restriction. In addition, maternal Cd exposure on GD8 reduced placental weight and diameter. The internal space of maternal and fetal blood vessels in the labyrinth layer was decreased in the placentas of mice treated with CdCl{sub 2}. Additional experiment showed that placental PCFT protein and mRNA, a critical folate transporter, was persistently decreased when dams were injected with CdCl{sub 2} on GD8. Correspondingly, embryonic folate content was markedly decreased in mice injected with CdCl{sub 2} on GD8, whereas Cd had little effect on folate content in maternal serum. Taken together, these results suggest that maternal Cd exposure during organogenesis disturbs transport of folate from maternal circulation to the fetuses through down-regulating placental folate transporters. - Highlights: • Maternal Cd exposure during organogenesis causes NTDs and FGR. • Maternal Cd exposure during organogenesis impairs placental development. • Cd disturbs transport of folate by down-regulating placental folate transporters.

  13. THYROID HORMONE REVERSES AGING-INDUCED MYOCARDIAL FATTY ACID OXIDATION DEFECTS AND IMPROVES THE RESPONSE TO ACUTELY INCREASED AFTERLOAD

    Energy Technology Data Exchange (ETDEWEB)

    Ledee, Dolena; Portman, Michael A.; Kajimoto, Masaki; Isern, Nancy G.; Olson, Aaron

    2013-06-07

    Background: Subclinical hypothyroidism occurs during aging in humans and mice and may contribute to development of heart failure. Aging also impairs myocardial fatty acid oxidation, causing increased reliance on flux through pyruvate dehydrogenase (PDH) to maintain function. We hypothesize that the metabolic changes in aged hearts make them less tolerant to acutely increased work and that thyroid hormone reverses these defects. Methods: Studies were performed on young (Young, 4-6 months) and aged (Old, 22-24 months) C57/BL6 mice at standard (50 mmHg) and high afterload (80 mmHg). Another aged group received thyroid hormone for 3 weeks (Old-TH, high afterload only). Function was measured in isolated working hearts along with substrate fractional contributions (Fc) to the citric acid cycle (CAC) using perfusate with 13C labeled lactate, pyruvate, glucose and unlabeled palmitate and insulin. Results: Cardiac function was similar between Young and Old mice at standard afterload. Palmitate Fc was reduced but no individual carbohydrate contributions differed. CAC and individual substrate fluxes decreased in aged. At high afterload, -dP/dT was decreased in Old versus Young. Similar to low afterload, palmitate Fc was decreased in Old. Thyroid hormone reversed aging-induced changes in palmitate Fc and flux while significantly improving cardiac function. Conclusion: The aged heart shows diminished ability to increase cardiac work due to substrate limitations, primarily impaired fatty acid oxidation. The heart accommodates slightly by increasing efficiency through oxidation of carbohydrate substrates. Thyroid hormone supplementation in aged mice significantly improves cardiac function potentially through restoration of fatty acid oxidation.

  14. Failure of irradiated beef and ham to induce genetic aberrations of Drosophila

    International Nuclear Information System (INIS)

    Mittler, S.

    1979-01-01

    Ham that had been irradiated by electrons and beef which had been exposed to gamma rays from 60 Co were fed to Drosophila melanogaster to determine whether meat sterilized by these methods would induce genetic aberrations. The results showed that for yB/sc 8 y + Y males, fed on irradiated ham or beef, thermally preserved beef or frozen beef for their entire larval life, there was no significant increase in the loss of X or Y chromosomes or non-disjunction of these chromosomes; there was also no significant increase in any of the broods. Similarly for the Oregon R males, there was no significant increase in yield of sex-linked recessive lethals. Thus feeding of irradiated ham and beef to Drosophila males did not induce significant increases in genetic aberrations. The present findings are discussed in relation to the conflicting results of previous studies. (U.K.)

  15. Defective IL-10 signaling in hyper-IgE syndrome results in impaired generation of tolerogenic dendritic cells and induced regulatory T cells

    Science.gov (United States)

    Saito, Masako; Nagasawa, Masayuki; Takada, Hidetoshi; Hara, Toshiro; Tsuchiya, Shigeru; Agematsu, Kazunaga; Yamada, Masafumi; Kawamura, Nobuaki; Ariga, Tadashi; Tsuge, Ikuya; Nonoyama, Shigeaki; Karasuyama, Hajime

    2011-01-01

    Hyper-IgE syndrome (HIES) is a primary immunodeficiency characterized by recurrent staphylococcal infections and atopic dermatitis associated with elevated serum IgE levels. Although defective differentiation of IL-17–producing CD4+ T cells (Th17) partly accounts for the susceptibility to staphylococcal skin abscesses and pneumonia, the pathogenesis of atopic manifestations in HIES still remains an enigma. In this study, we examined the differentiation and function of Th1, Th2, regulatory T cells (Treg cells), and dendritic cells (DCs) in HIES patients carrying either STAT3 or TYK2 mutations. Although the in vitro differentiation of Th1 and Th2 cells and the number and function of Treg cells in the peripheral blood were normal in HIES patients with STAT3 mutations, primary and monocyte-derived DCs showed defective responses to IL-10 and thus failed to become tolerogenic. When treated with IL-10, patient DCs showed impaired up-regulation of inhibitory molecules on their surface, including PD-L1 and ILT-4, compared with control DCs. Moreover, IL-10–treated DCs from patients displayed impaired ability to induce the differentiation of naive CD4+ T cells to FOXP3+ induced Treg cells (iTreg cells). These results suggest that the defective generation of IL-10–induced tolerogenic DCs and iTreg cells may contribute to inflammatory changes in HIES. PMID:21300911

  16. The protective effect of hypoxia and dithiothreitol on X-ray-induced genetic damage in Arabidopsis

    International Nuclear Information System (INIS)

    Sree Ramulu, K.; Veen, J.H. van der

    1987-01-01

    A study was made on the protective effect of hypoxia and dithiothreitol (DTT) on X-ray-induced ovule sterility and embryonic lethality in Arabidopsis. Both hypoxia and DTT gave a pronounced and additive reduction of radiation-induced genetic damage. The reduction was significantly higher for ovule sterility than for embryonic lethals. It is suggested that non-fertilized ovules contain a higher ratio of strand breaks/other damage than embryonic lethals do, for hypoxia and DTT are known specifically to give a reduction of strand breaks. (Auth.)

  17. Genetic and molecular analysis of radon-induced rat lung tumours

    International Nuclear Information System (INIS)

    Guilly, M.N.; Joubert, Ch.; Levalois, C.; Dano, L.; Chevillard, S.

    2002-01-01

    We have a model of radon-induced rat lung tumours, which allow us to analyse the cytogenetic and molecular alterations of the tumours. The aim is to better understand the mechanisms of radio-induced carcinogenesis and to define if it exists a specificity of radio-induced genetic alterations as compared to the genetic alterations found in the sporadic tumours. We have started our analysis by developing global cytogenetic and molecular approaches. We have shown that some alterations are recurrent. The genes that are potentially involved are the oncogene MET and the tumour suppressor Bene p16, which are also frequently altered in human lung tumours. Simultaneously, we have focussed our analysis by targeting the search of mutation in the tumour suppressor gene TP3. We have found that 8 of 39 tumours were mutated by deletion in the coding sequence of TP53. This high frequency of deletion, which is not observed in the human p53 mutation database could constitute a signature of radio-induced alterations. On this assumption, this type of alteration should not be only found on TP53 Bene but also in other suppressor genes which are inactivated by a mutation such as p16 for example. The work we are carrying out on radio-induced tumours among humans and animals is directed to this end. (author)

  18. Radiation-Induced Defects in Kaolinite as Tracers of Past Occurrence of Radionuclides in a Natural Analogue of High Level Nuclear Waste Repository

    Science.gov (United States)

    Allard, T.; Fourdrin, C.; Calas, G.

    2007-05-01

    Understanding the processes controlling migrations of radioelements at the Earth's surface is an important issue for the long-term safety assessment of high level nuclear waste repositories (HLNWR). Evidence of past occurrence and transfer of radionuclides can be found using radiation-induced defects in minerals. Clay minerals are particularly relevant because of their widespread occurrence at the Earth's surface and their finely divided nature which provides high contact area with radioactive fluids. Owing to its sensitivity to radiations, kaolinite can be used as natural, in situ dosimeter. Kaolinite is known to contain radiation-induced defects which are detected by Electron Paramagnetic Resonance. They are differentiated by their nature, their production kinetics and their thermal stability. One of these defects is stable at the scale of geological periods and provides a record of past radionuclide occurrence. Based on artificial irradiations, a methodology has been subsequently proposed to determine paleodose cumulated by kaolinite since its formation. The paleodose can be used to derive equivalent radioelement concentrations, provided that the age of kaolinite formation can be constrained. This allows quantitative reconstruction of past transfers of radioelements in natural systems. An example is given for the Nopal I U-deposit (Chihuahua, Mexico), hosted in hydrothermally altered volcanic tufs and considered as analogue of the Yucca Mountain site. The paleodoses experienced by kaolinites were determined from the concentration of defects and dosimetry parameters of experimental irradiations. Using few geochemical assumption, a equivalent U-content responsible for defects in kaolinite was calculated from the paleodose, a dose rate balance and model ages of kaolinites constrained by tectonic phases. In a former study, the ages were assumptions derived from regional tectonic events. In thepresent study, ages of mineralization events are measured from U

  19. Persistent genetic instability induced by synergistic interaction between x-irradiation and 6-thioguanine

    International Nuclear Information System (INIS)

    Grosovsky, A.J.; Nelson, S.L.; Smith, L.E.

    1995-01-01

    Clonal karyotypic analysis was performed using G-banding on four groups of clones derived from TK6 human lymphoblasts: 25 HPRT - total gene deletion mutants induced by exposure to 2 Gy of x-rays; 8 spontaneous HPRT - total gene deletion mutants; 25 clones irradiated with 2 Gy, not selected with 6-thioguanine. Ten to twenty metaphases were examined for each clone. Extensive karyotypic heterogeneity was observed among x-ray induced HPRT - mutants involving translocations, deletions, duplications and aneuploidy; recovery of chromosomal aberrations and karyotypic heterogeneity was greater than the additive effects of clones treated with x-irradiation or 6-thioguanine alone. This synergistic interaction between x-irradiation and 6-thioguanine was observed despite a 7 day phenotypic expression interval between exposure to the two agents. Thus, x-irradiated TK6 cells appear to be persistently hypersensitive to the induction of genetic instability. Several mutants appeared to exhibit evidence of clonal evolution since aberrant chromosomes observed in one metaphase, were found to be further modified in other metaphases. In order to determine if genetic instability, identified by clonal karyotypic heterogeneity, affected specific locus mutation rates, we utilized the heterozygous thymidine kinase (tk) locus as a genetic marker. Four x-ray induced HPRT - mutants with extensive karyotypic heterogeneity, exhibited mutation rates at tk ranging from 5 to 8 fold higher than the parental TK6 cells. Further analysis, using fractionated low dose radiation exposure, is currently in progress

  20. Recombination-induced formation of hydrogen-defect complexes in 4H and 6H-SiC: electrical and optical characterization

    International Nuclear Information System (INIS)

    Koshka, Y.; Los, A.; Mazzola, M.S.; Sankin, I.

    2003-01-01

    The phenomenon of recombination-induced passivation of defects with hydrogen was investigated in SiC polytypes. Excitation of the hydrogenated samples with above-band gap light at low temperatures resulted in formation of different non-metastable hydrogen-related luminescence centres. Electrical measurements revealed strong recombination-induced passivation of electrical activity of aluminium and boron acceptors in p-type SiC epilayers, which in some cases resulted in inversion of the conductivity type. Athermal migration of hydrogen is considered as a possible mechanism for the observed phenomena

  1. Vascular defects in gain-of-function fps/fes transgenic mice correlate with PDGF- and VEGF-induced activation of mutant Fps/Fes kinase in endothelial cells.

    Science.gov (United States)

    Sangrar, W; Mewburn, J D; Vincent, S G; Fisher, J T; Greer, P A

    2004-05-01

    Fps/Fes is a cytoplasmic tyrosine kinase that is abundantly expressed in the myeloid, endothelial, epithelial, neuronal and platelet lineages. Genetic manipulation in mice has uncovered potential roles for this kinase in hematopoiesis, innate immunity, inflammation and angiogenesis. We have utilized a genetic approach to explore the role of Fps/Fes in angiogenesis. A hypervascular line of mice generated by expression of a 'gain-of-function' human fps/fes transgene (fps(MF)) encoding a myristoylated variant of Fps (MFps) was used in these studies. The hypervascular phenotype of this line was extensively characterized by intravital microscopy and biochemical approaches. fps(MF) mice exhibited 1.6-1.7-fold increases in vascularity which was attributable to increases in the number of secondary vessels. Vessels were larger, exhibited varicosities and disorganized patterning, and were found to have defects in histamine-induced permeability. Biochemical characterization of endothelial cell (EC) lines derived from fps(MF) mice revealed that MFps was hypersensitive to activation by vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF). MFps mediates enhanced sensitization to VEGF and PDGF signaling in ECs. We propose that this hypersensitization contributes to excessive angiogenic signaling and that this underlies the observed hypervascular phenotype of fps(MF) mice. These phenotypes recapitulate important aspects of the vascular defects observed in both VEGF and angiopoietin-1 transgenic mice. The fps/fes proto-oncogene product therefore represents a novel player in the regulation of angiogenesis, and the fps(MF) line of mice constitutes a unique new murine model for the study of this process.

  2. Defect modelling

    International Nuclear Information System (INIS)

    Norgett, M.J.

    1980-01-01

    Calculations, drawing principally on developments at AERE Harwell, of the relaxation about lattice defects are reviewed with emphasis on the techniques required for such calculations. The principles of defect modelling are outlined and various programs developed for defect simulations are discussed. Particular calculations for metals, ionic crystals and oxides, are considered. (UK)

  3. Comparison of the frequency of defective sperm-zona pellucida (ZP) binding and the ZP-induced acrosome reaction between subfertile men with normal and abnormal semen.

    Science.gov (United States)

    Liu, De Yi; Liu, Ming Li; Garrett, Claire; Baker, H W Gordon

    2007-07-01

    The aim of this study was to compare the frequency of defective sperm-zona pellucida (ZP) binding (DSZPB) and defective ZP-induced acrosome reaction (DZPIAR) in subfertile men (i.e. male partners of infertile couples) with normal and abnormal semen analyses. A total of 1030 subfertile men with normal semen analysis (n=255), oligozoospermia (countsperm injection were used for sperm-ZP interaction tests. After 2 h incubation of motile sperm with four oocytes, sperm tightly bound to the ZP, and the AR of ZP-bound sperm (ZPIAR) were assessed. An average of sperm bound/ZP and sperm-ZP interaction were in the oligozoospermia and severe teratozoospermia groups. In the normal and teratozoospermia groups, subjects with a relatively low sperm concentration (20-60x10(6)/ml) had a significantly higher frequency of DZPIAR. Defective sperm-ZP interaction is a major mechanism of male infertility. DZPIAR is more frequent than DSZPB in subfertile men with either normal or abnormal semen, suggesting that sequential sperm-ZP interaction tests are essential to detect these sperm defects.

  4. Neuron-specific knockdown of the Drosophila fat induces reduction of life span, deficient locomotive ability, shortening of motoneuron terminal branches and defects in axonal targeting.

    Science.gov (United States)

    Nakamura, Aya; Tanaka, Ryo; Morishita, Kazushige; Yoshida, Hideki; Higuchi, Yujiro; Takashima, Hiroshi; Yamaguchi, Masamitsu

    2017-07-01

    Mutations in FAT4 gene, one of the human FAT family genes, have been identified in Van Maldergem syndrome (VMS) and Hennekam lymphangiectasia-lymphedema syndrome (HS). The FAT4 gene encodes a large protein with extracellular cadherin repeats, EGF-like domains and Laminin G-like domains. FAT4 plays a role in tumor suppression and planar cell polarity. Drosophila contains a human FAT4 homologue, fat. Drosophila fat has been mainly studied with Drosophila eye and wing systems. Here, we specially knocked down Drosophila fat in nerve system. Neuron-specific knockdown of fat shortened the life span and induced the defect in locomotive abilities of adult flies. In consistent with these phenotypes, defects in synapse structure at neuromuscular junction were observed in neuron-specific fat-knockdown flies. In addition, aberrations in axonal targeting of photoreceptor neuron in third-instar larvae were also observed, suggesting that fat involves in axonal targeting. Taken together, the results indicate that Drosophila fat plays an essential role in formation and/or maintenance of neuron. Both VMS and HS show mental retardation and neuronal defects. We therefore consider that these two rare human diseases could possibly be caused by the defect in FAT4 function in neuronal cells. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  5. Defect induced structural inhomogeneity, ultraviolet light emission and near-band-edge photoluminescence broadening in degenerate In2O3 nanowires

    Science.gov (United States)

    Mukherjee, Souvik; Sarkar, Ketaki; Wiederrecht, Gary P.; Schaller, Richard D.; Gosztola, David J.; Stroscio, Michael A.; Dutta, Mitra

    2018-04-01

    We demonstrate here defect induced changes on the morphology and surface properties of indium oxide (In2O3) nanowires and further study their effects on the near-band-edge (NBE) emission, thereby showing the significant influence of surface states on In2O3 nanostructure based device characteristics for potential optoelectronic applications. In2O3 nanowires with cubic crystal structure (c-In2O3) were synthesized via carbothermal reduction technique using a gold-catalyst-assisted vapor-liquid-solid method. Onset of strong optical absorption could be observed at energies greater than 3.5 eV consistent with highly n-type characteristics due to unintentional doping from oxygen vacancy ({V}{{O}}) defects as confirmed using Raman spectroscopy. A combination of high resolution transmission electron microscopy, x-ray photoelectron spectroscopy and valence band analysis on the nanowire morphology and stoichiometry reveals presence of high-density of {V}{{O}} defects on the surface of the nanowires. As a result, chemisorbed oxygen species can be observed leading to upward band bending at the surface which corresponds to a smaller valence band offset of 2.15 eV. Temperature dependent photoluminescence (PL) spectroscopy was used to study the nature of the defect states and the influence of the surface states on the electronic band structure and NBE emission has been discussed. Our data reveals significant broadening of the NBE PL peak consistent with impurity band broadening leading to band-tailing effect from heavy doping.

  6. Defect induced structural inhomogeneity, ultraviolet light emission and near-band-edge photoluminescence broadening in degenerate In 2 O 3 nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Souvik; Sarkar, Ketaki; Wiederrecht, Gary P.; Schaller, Richard D.; Gosztola, David J.; Stroscio, Michael A.; Dutta, Mitra

    2018-03-01

    We demonstrate here defect induced changes on the morphology and surface properties of indium oxide (In2O3) nanowires and further study their effects on the near-band-edge (NBE) emission, thereby showing the significant influence of surface states on In2O3 nanostructure based device characteristics for potential optoelectronic applications. In2O3 nanowires with cubic crystal structure (c-In2O3) were synthesized via carbothermal reduction technique using a gold-catalyst-assisted vapor–liquid–solid method. Onset of strong optical absorption could be observed at energies greater than 3.5 eV consistent with highly n-type characteristics due to unintentional doping from oxygen vacancy (VO) defects as confirmed using Raman spectroscopy. A combination of high resolution transmission electron microscopy, x-ray photoelectron spectroscopy and valence band analysis on the nanowire morphology and stoichiometry reveals presence of high-density of VO defects on the surface of the nanowires. As a result, chemisorbed oxygen species can be observed leading to upward band bending at the surface which corresponds to a smaller valence band offset of 2.15 eV. Temperature dependent photoluminescence (PL) spectroscopy was used to study the nature of the defect states and the influence of the surface states on the electronic band structure and NBE emission has been discussed. Our data reveals significant broadening of the NBE PL peak consistent with impurity band broadening leading to band-tailing effect from heavy doping.

  7. Analysis of nano-sized irradiation-induced defects in Fe-base materials by means of small angle neutron scattering and molecular dynamics simulations

    International Nuclear Information System (INIS)

    Yu, G.

    2008-12-01

    Thermonuclear fusion of light atoms is considered since decades as an unlimited, safe and reliable source of energy that could eventually replace classical sources based on fossil fuel or nuclear fuel. Fusion reactor technology and materials studies are important parts of the fusion energy development program. For the time being, the most promising materials for structural applications in the future fusion power reactors are the Reduced Activation Ferritic/Martensitic (RAFM) steels for which the greatest technology maturity has been achieved, i.e., qualified fabrication routes, welding technology and a general industrial experience are almost available. The most important issues concerning the future use of RAFM steels in fusion power reactors are derived from their irradiation by 14 MeV neutrons that are the product, together with 3.5 MeV helium ions, of the envisaged fusion reactions between deuterium and tritium nuclei. Indeed, exposure of metallic materials to intense fluxes of 14 MeV neutrons will result in the formation of severe displacement damage (about 20-30 dpa per year) and high amounts of helium, which are at the origin of significant changes in the physical and mechanical properties of materials, such as hardening and embrittlement effects. This PhD Thesis work was aimed at investigating how far the Small Angle Neutron Scattering (SANS) technique could be used for detecting and characterizing nano-sized irradiation-induced defects in RAFM steels. Indeed, the resolution limit of Transmission Electron Microscopy (TEM) is about 1 nm in weak beam TEM imaging, and it is usually thought that a large number of irradiation-induced effects have a size below 1 nm in RAFM steels and that these very small defects actually contribute to the irradiation-induced hardening and embrittlement of RAFM steels occurring at irradiation temperatures below about 400 °C. The aim of this work was achieved by combining SANS experiments on unirradiated and irradiated specimens

  8. Tramadol Induced Adrenal Insufficiency: Histological, Immunohistochemical, Ultrastructural, and Biochemical Genetic Experimental Study

    Directory of Open Access Journals (Sweden)

    Shereen Abdelhakim Abdelaleem

    2017-01-01

    Full Text Available Tramadol is a synthetic, centrally acting analgesic. It is the most consumed narcotic drug that is prescribed in the world. Tramadol abuse has dramatically increased in Egypt. Long term use of tramadol can induce endocrinopathy. So, the aim of this study was to analyze the adrenal insufficiency induced by long term use of tramadol in experimental animals and also to assess its withdrawal effects through histopathological and biochemical genetic study. Forty male albino rats were used in this study. The rats were divided into 4 groups (control group, tramadol-treated group, and withdrawal groups. Tramadol was given to albino rats at a dose of 80 mg/kg body weight for 3 months and after withdrawal periods (7–15 days rats were sacrificed. Long term use of tramadol induced severe histopathological changes in adrenal glands. Tramadol decreased the levels of serum cortisol and DHEAS hormones. In addition, it increased the level of adrenal MDA and decreased the genetic expression of glutathione peroxidase and thioredoxin reductase in adrenal gland tissues. All these changes started to return to normal after withdrawal of tramadol. Thus, it was confirmed that long term use of tramadol can induce severe adrenal insufficiency.

  9. Tramadol Induced Adrenal Insufficiency: Histological, Immunohistochemical, Ultrastructural, and Biochemical Genetic Experimental Study.

    Science.gov (United States)

    Abdelaleem, Shereen Abdelhakim; Hassan, Osama A; Ahmed, Rasha F; Zenhom, Nagwa M; Rifaai, Rehab A; El-Tahawy, Nashwa F

    2017-01-01

    Tramadol is a synthetic, centrally acting analgesic. It is the most consumed narcotic drug that is prescribed in the world. Tramadol abuse has dramatically increased in Egypt. Long term use of tramadol can induce endocrinopathy. So, the aim of this study was to analyze the adrenal insufficiency induced by long term use of tramadol in experimental animals and also to assess its withdrawal effects through histopathological and biochemical genetic study. Forty male albino rats were used in this study. The rats were divided into 4 groups (control group, tramadol-treated group, and withdrawal groups). Tramadol was given to albino rats at a dose of 80 mg/kg body weight for 3 months and after withdrawal periods (7-15 days) rats were sacrificed. Long term use of tramadol induced severe histopathological changes in adrenal glands. Tramadol decreased the levels of serum cortisol and DHEAS hormones. In addition, it increased the level of adrenal MDA and decreased the genetic expression of glutathione peroxidase and thioredoxin reductase in adrenal gland tissues. All these changes started to return to normal after withdrawal of tramadol. Thus, it was confirmed that long term use of tramadol can induce severe adrenal insufficiency.

  10. Genetic and epigenetic variations induced by wheat-rye 2R and 5R monosomic addition lines.

    Science.gov (United States)

    Fu, Shulan; Sun, Chuanfei; Yang, Manyu; Fei, Yunyan; Tan, Feiqun; Yan, Benju; Ren, Zhenglong; Tang, Zongxiang

    2013-01-01

    Monosomic alien addition lines (MAALs) can easily induce structural variation of chromosomes and have been used in crop breeding; however, it is unclear whether MAALs will induce drastic genetic and epigenetic alterations. In the present study, wheat-rye 2R and 5R MAALs together with their selfed progeny and parental common wheat were investigated through amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP) analyses. The MAALs in different generations displayed different genetic variations. Some progeny that only contained 42 wheat chromosomes showed great genetic/epigenetic alterations. Cryptic rye chromatin has introgressed into the wheat genome. However, one of the progeny that contained cryptic rye chromatin did not display outstanding genetic/epigenetic variation. 78 and 49 sequences were cloned from changed AFLP and MSAP bands, respectively. Blastn search indicated that almost half of them showed no significant similarity to known sequences. Retrotransposons were mainly involved in genetic and epigenetic variations. Genetic variations basically affected Gypsy-like retrotransposons, whereas epigenetic alterations affected Copia-like and Gypsy-like retrotransposons equally. Genetic and epigenetic variations seldom affected low-copy coding DNA sequences. The results in the present study provided direct evidence to illustrate that monosomic wheat-rye addition lines could induce different and drastic genetic/epigenetic variations and these variations might not be caused by introgression of rye chromatins into wheat. Therefore, MAALs may be directly used as an effective means to broaden the genetic diversity of common wheat.

  11. Gadolinium substitution induced defect restructuring in multiferroic BiFeO3: case study by positron annihilation spectroscopy

    Science.gov (United States)

    Mukherjee, A.; Banerjee, M.; Basu, S.; Nambissan, P. M. G.; Pal, M.

    2013-12-01

    Positron annihilation spectroscopy (PAS) comprising of the measurements of positron lifetime and coincidence Doppler broadening spectra has been carried out to understand and monitor the evolution of the vacancy-type defects arising from the ionic deficiencies at lattice points of the multiferroic perovskite bismuth ferrite (BiFeO3) doped with 1, 5 and 10 at% gadolinium (Gd3+) ions. Negatively charged defects in the form of Bi3+ monovacancies (V_{Bi}^{3-} ) were present in the undoped nanocrystallites, which strongly trapped positrons. During the successive doping by Gd3+ ions, the positron trapping efficiency decreased while the doped ions combined with the vacancies to form complexes, which became neutral. A fraction of the positrons got annihilated at the crystallite surfaces too, being evident from the very large positron lifetimes obtained and confirming the nano-size-specific characteristics of the samples. Further, the intercrystallite regions provided favourable sites for orthopositronium formation, although in minute concentrations. The dopant ion-complex formation was also depicted clearly by the defect characteristic S-W plot. Also, the large change of electrical resistivity with Gd concentration has been explained nicely by invoking the defect information from the PAS study. The study has demonstrated the usefulness of an excellent method of defect identification in such a novel material system, which is vital information for exploiting them for further technological applications.

  12. Edge-defect induced spin-dependent Seebeck effect and spin figure of merit in graphene nanoribbons.

    Science.gov (United States)

    Liu, Qing-Bo; Wu, Dan-Dan; Fu, Hua-Hua

    2017-10-11

    By using the first-principle calculations combined with the non-equilibrium Green's function approach, we have studied spin caloritronic properties of graphene nanoribbons (GNRs) with different edge defects. The theoretical results show that the edge-defected GNRs with sawtooth shapes can exhibit spin-dependent currents with opposite flowing directions by applying temperature gradients, indicating the occurrence of the spin-dependent Seebeck effect (SDSE). The edge defects bring about two opposite effects on the thermal spin currents: the enhancement of the symmetry of thermal spin-dependent currents, which contributes to the realization of pure thermal spin currents, and the decreasing of the spin thermoelectric conversion efficiency of the devices. It is fortunate that applying a gate voltage is an efficient route to optimize these two opposite spin thermoelectric properties towards realistic device applications. Moreover, due to the existence of spin-splitting band gaps, the edge-defected GNRs can be designed as spin-dependent Seebeck diodes and rectifiers, indicating that the edge-defected GNRs are potential candidates for room-temperature spin caloritronic devices.

  13. Identification of genetic factors associated with susceptibility to angiotensin-converting enzyme inhibitors-induced cough.

    Science.gov (United States)

    Grilo, Antonio; Sáez-Rosas, María P; Santos-Morano, Juan; Sánchez, Elena; Moreno-Rey, Concha; Real, Luis M; Ramírez-Lorca, Reposo; Sáez, María E

    2011-01-01

    Angiotensin-converting enzyme inhibitors (ACEi) are the first selected drugs for hypertensive patients because of its protective properties against heart and kidney diseases. Persistent cough is a common adverse reaction associated with ACEi, which can bind to the treatment cessation, but its etiology remains an unresolved issue. The most accepted mechanism is that the inhibition of ACEi increases kinins levels, resulting in the activation of proinflammatory mechanisms and nitric oxide generation. However, relatively little is known about the genetic susceptibility to ACEi-induced cough in hypertensive patients. We carried out a monogenic association analysis of 39 polymorphisms and haplotypes in genes encoding key proteins related to ACEi activity with the occurrence of ACEi-induced cough. We also carried out a digenic association analysis and investigated the existence of epistatic interactions between the analyzed polymorphisms using a logistic regression procedure. Finally, we investigated the predictive value of the identified associations for ACEi-induced cough. We found that genetic polymorphisms in MME [rs2016848, P=0.002, odds ratio (OR)=1.795], BDKRB2 (rs8012552, P=0.012, OR=1.609), PTGER3 (rs11209716, P=0.002, OR=0.565), and ACE (rs4344) genes are associated with ACEi-related cough. For the latter, the effect is sex specific, having a protective effect in males (P=0.027, OR=0.560) and increasing the risk in females (P=0.031, OR=1.847). In addition, genetic interactions between peptidases involved in kinins levels (CPN1 and XPNPEP1) and proteins related to prostaglandin metabolism (PTGIS and PTGIR) strongly modify the risk of ACEi-induced cough presentation (0.102≤OR≤0.384 for protective combinations and 2.732≤OR≤7.216 for risk combinations). These results are consistent with the hypothesis that the mechanism of cough is related to the accumulation of bradykinin, substance P, and prostaglandins.

  14. New inducible genetic method reveals critical roles of GABA in the control of feeding and metabolism.

    Science.gov (United States)

    Meng, Fantao; Han, Yong; Srisai, Dollada; Belakhov, Valery; Farias, Monica; Xu, Yong; Palmiter, Richard D; Baasov, Timor; Wu, Qi

    2016-03-29

    Currently available inducible Cre/loxP systems, despite their considerable utility in gene manipulation, have pitfalls in certain scenarios, such as unsatisfactory recombination rates and deleterious effects on physiology and behavior. To overcome these limitations, we designed a new, inducible gene-targeting system by introducing an in-frame nonsense mutation into the coding sequence of Cre recombinase (nsCre). Mutant mRNAs transcribed from nsCre transgene can be efficiently translated into full-length, functional Cre recombinase in the presence of nonsense suppressors such as aminoglycosides. In a proof-of-concept model, GABA signaling from hypothalamic neurons expressing agouti-related peptide (AgRP) was genetically inactivated within 4 d after treatment with a synthetic aminoglycoside. Disruption of GABA synthesis in AgRP neurons in young adult mice led to a dramatic loss of body weight due to reduced food intake and elevated energy expenditure; they also manifested glucose intolerance. In contrast, older mice with genetic inactivation of GABA signaling by AgRP neurons had only transient reduction of feeding and body weight; their energy expenditure and glucose tolerance were unaffected. These results indicate that GABAergic signaling from AgRP neurons plays a key role in the control of feeding and metabolism through an age-dependent mechanism. This new genetic technique will augment current tools used to elucidate mechanisms underlying many physiological and neurological processes.

  15. Genetic analyses of nonfluorescent root mutants induced by mutagenesis in soybean

    International Nuclear Information System (INIS)

    Sawada, S.; Palmer, R.G.

    1987-01-01

    Nonfluorescent root mutants in soybean [Glycine max (L.) Merr.] are useful as markers in genetic studies and in tissue culture research. Our objective was to obtain mutagen-induced nonfluorescent root mutants and to conduct genetic studies with them. Thirteen nonfluorescent mutants were detected among 154016 seedlings derived from soybean lines treated with six mutagens. One of these mutants, derived from Williams treated with 20 kR gamma rays, did not correspond to any of the known (standard) nonfluorescent spontaneous mutants. This is the first mutagen-induced nonfluorescent root mutant in soybean. It was assigned Genetic Type Collection no. T285 and the gene symbol fr5 fr5. The fr5 allele was not located on trisomics A, B, or C and was not linked to five chlorophyll-deficient mutants (y9, y11, y12, y13, and y20-k2) or flower color mutant w1. The remaining nonfluorescent root mutants were at the same loci as known spontaneous mutants; i.e., four had the fr1 allele, five had the fr2 allele, and three had the fr4 allele

  16. Detection of Genetic Variations in Marine Algae Ulva lactuca (Chlorophyta Induced by Heavy Metal Pollutants

    Directory of Open Access Journals (Sweden)

    Basel Saleh

    2015-09-01

    Full Text Available Ulva lactuca (Chlorophyta green macroalgae has been successfully used as bioindicator for heavy metals pollution in ecosystems. Random amplified microsatellite polymorphism (RAMP marker was employed to investigate genetic DNA pattern variability in green U. lactuca 5 days after exposure to Cu, Pb, Cd and Zn heavy metals stress. Genomic template stability (GTS% value was employed as a qualitative DNA changes measurement based on RAMP technique. In this respect, estimated GTS% value was recorded to be 65.215, 64.630, 59.835 and 59.250% for Pb, Cu, Cd and Zn treatment, respectively. Moreover, genetic similarity (GS induced by the above heavy metals was also evaluated to measure genetic distance between algae treated plants and their respective control. In this respect, estimated GS values generated by RAMP marker ranged between 0.576 (between control and Zn treatment - 0.969 (for both case; between Pb and Cu and between Cd and Zn treatment with an average of 0.842. Based upon data presented herein based on variant bands number (VB, GTS% and GS values; the present study could be suggested that Pb and Cu followed similar tendency at genomic DNA changes. Similar finding was also observed with Cd and Zn ions. Thereby, RAMP marker successfully highlighted DNA change patterns induced by heavy metals stress.

  17. Genetic variation in CFH predicts phenytoin-induced maculopapular exanthema in European-descent patients.

    Science.gov (United States)

    McCormack, Mark; Gui, Hongsheng; Ingason, Andrés; Speed, Doug; Wright, Galen E B; Zhang, Eunice J; Secolin, Rodrigo; Yasuda, Clarissa; Kwok, Maxwell; Wolking, Stefan; Becker, Felicitas; Rau, Sarah; Avbersek, Andreja; Heggeli, Kristin; Leu, Costin; Depondt, Chantal; Sills, Graeme J; Marson, Anthony G; Auce, Pauls; Brodie, Martin J; Francis, Ben; Johnson, Michael R; Koeleman, Bobby P C; Striano, Pasquale; Coppola, Antonietta; Zara, Federico; Kunz, Wolfram S; Sander, Josemir W; Lerche, Holger; Klein, Karl Martin; Weckhuysen, Sarah; Krenn, Martin; Gudmundsson, Lárus J; Stefánsson, Kári; Krause, Roland; Shear, Neil; Ross, Colin J D; Delanty, Norman; Pirmohamed, Munir; Carleton, Bruce C; Cendes, Fernando; Lopes-Cendes, Iscia; Liao, Wei-Ping; O'Brien, Terence J; Sisodiya, Sanjay M; Cherny, Stacey; Kwan, Patrick; Baum, Larry; Cavalleri, Gianpiero L

    2018-01-23

    To characterize, among European and Han Chinese populations, the genetic predictors of maculopapular exanthema (MPE), a cutaneous adverse drug reaction common to antiepileptic drugs. We conducted a case-control genome-wide association study of autosomal genotypes, including Class I and II human leukocyte antigen (HLA) alleles, in 323 cases and 1,321 drug-tolerant controls from epilepsy cohorts of northern European and Han Chinese descent. Results from each cohort were meta-analyzed. We report an association between a rare variant in the complement factor H-related 4 ( CFHR4 ) gene and phenytoin-induced MPE in Europeans ( p = 4.5 × 10 -11 ; odds ratio [95% confidence interval] 7 [3.2-16]). This variant is in complete linkage disequilibrium with a missense variant (N1050Y) in the complement factor H ( CFH ) gene. In addition, our results reinforce the association between HLA-A*31:01 and carbamazepine hypersensitivity. We did not identify significant genetic associations with MPE among Han Chinese patients. The identification of genetic predictors of MPE in CFHR4 and CFH, members of the complement factor H-related protein family, suggest a new link between regulation of the complement system alternative pathway and phenytoin-induced hypersensitivity in European-ancestral patients. Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

  18. Al-Aqeel Sewairi Syndrome, a new autosomal recessive disorder with multicentric osteolysis, nodulosis and arthropathy. The first genetic defect of matrix metalloproteinase 2 gene

    International Nuclear Information System (INIS)

    Al-Aqeel, Aida I.

    2005-01-01

    We report a distinctive autosomal recessive multicentric osteolysis in Saudi Arabian families with distal arthropathy of the metacarpal, metatarsal and interphalangeal joints, with ultimate progression to the proximal joints with decreased range of movements and deformities with ankylosis and generalized osteopenia. In addition, they had large, painful to touch palmar and plantar pads. Hirsutism and mild dysmorphic facial features including proptosis, a narrow nasal bridge, bulbous nose and micrognathia. Using a genome-wide search for microsatellite markers from 11 members of the family from the Armed Forces Hospital and King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia, localized the disease gene to chromosome 16q12-21. Haplotype analysis with additional markers narrowed the critical region to 1.2cM and identified the matrix metalloproteinase 2 (MMP-2), (gelatinase A, collagenase type IV, EC 3.4, 24,24) gene as a disease candidate at Mount Sinai School of Medicine, New York, United States of America in April 2000. Some affected individuals were homoallelic for a nonsense mutation (TCA>TAA) in codon 244 of exon 5, predicting the replacement of a tyrosine residue by a stop codon in the first fibronectin type II domain (Y244X). Other affected members had a missense mutation in exon 2 arginine 101-histidine (R101H) leading to no MMP-2 enzyme activity in serum or fibroblast or both of affected individuals. In other affected members, a non-pathogenic homoallelic GT transversion resulted in the substitution of an aspartate with a tyrosine residue in codon 210 of exon 4 (D210Y). The MMP-2-null mouse has no developmental defects, but are small, which may reflect genetic redundancy. The discovery that deficiency of this well-characterized gelatinase/collagenase results in an inherited form of an osteolytic and arthritic disorder provides an invaluable insights for the understanding of osteolysis and arthritis and is the first genetic

  19. Effect of random inhomogeneities in the spatial distribution of radiation-induced defect clusters on carrier transport through the thin base of a heterojunction bipolar transistor upon neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Puzanov, A. S.; Obolenskiy, S. V., E-mail: obolensk@rf.unn.ru; Kozlov, V. A. [Lobachevsky State University of Nizhny Novgorod (NNSU) (Russian Federation)

    2016-12-15

    We analyze the electron transport through the thin base of a GaAs heterojunction bipolar transistor with regard to fluctuations in the spatial distribution of defect clusters induced by irradiation with a fissionspectrum fast neutron flux. We theoretically demonstrate that the homogeneous filling of the working region with radiation-induced defect clusters causes minimum degradation of the dc gain of the heterojunction bipolar transistor.

  20. Genetics

    International Nuclear Information System (INIS)

    Hubitschek, H.E.

    1975-01-01

    Progress is reported on the following research projects: genetic effects of high LET radiations; genetic regulation, alteration, and repair; chromosome replication and the division cycle of Escherichia coli; effects of radioisotope decay in the DNA of microorganisms; initiation and termination of DNA replication in Bacillus subtilis; mutagenesis in mouse myeloma cells; lethal and mutagenic effects of near-uv radiation; effect of 8-methoxypsoralen on photodynamic lethality and mutagenicity in Escherichia coli; DNA repair of the lethal effects of far-uv; and near uv irradiation of bacterial cells

  1. Genetic heterogeneity of patients with suspected Silver-Russell syndrome: genome-wide copy number analysis in 82 patients without imprinting defects.

    Science.gov (United States)

    Inoue, Takanobu; Nakamura, Akie; Fuke, Tomoko; Yamazawa, Kazuki; Sano, Shinichiro; Matsubara, Keiko; Mizuno, Seiji; Matsukura, Yoshika; Harashima, Chie; Hasegawa, Tatsuji; Nakajima, Hisakazu; Tsumura, Kumi; Kizaki, Zenro; Oka, Akira; Ogata, Tsutomu; Fukami, Maki; Kagami, Masayo

    2017-01-01

    Silver-Russell syndrome (SRS) is a rare congenital disorder characterized by pre- and postnatal growth failure and dysmorphic features. Recently, pathogenic copy number variations (PCNVs) and imprinting defects other than hypomethylation of the H19 -differentially methylated region (DMR) and maternal uniparental disomy chromosome 7 have been reported in patients with the SRS phenotype. This study aimed to clarify the frequency and clinical features of patients with SRS phenotype caused by PCNVs. We performed array comparative genomic hybridization analysis using a catalog array for 54 patients satisfying the Netchine-Harbison clinical scoring system (NH-CSS) (SRS-compatible) and for 28 patients presenting with three NH-CSS items together with triangular face and/or fifth finger clinodactyly and/or brachydactyly (SRS-like) without abnormal methylation levels of 9 DMRs related to known imprinting disorders. We then investigated the clinical features of patients with PCNVs. Three of the 54 SRS-compatible patients (5.6%) and 2 of the 28 SRS-like patients (7.1%) had PCNVs. We detected 3.5 Mb deletion in 4p16.3, mosaic trisomy 18, and 3.77-4.00 Mb deletion in 19q13.11-12 in SRS-compatible patients, and 1.41-1.97 Mb deletion in 7q11.23 in both SRS-like patients. Congenital heart diseases (CHDs) were identified in two patients and moderate to severe global developmental delay was observed in four patients. Of the patients in our study, 5.6% of SRS-compatible and 7.1% of SRS-like patients had PCNVs. All PCNVs have been previously reported for genetic causes of contiguous deletion syndromes or mosaic trisomy 18. Our study suggests patients with PCNVs, who have a phenotype resembling SRS, show a high tendency towards CHDs and/or apparent developmental delay.

  2. Raman investigation of lattice defects and stress induced in InP and GaN films by swift heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, P.P. [Institute of Modern Physics, Chinese Academy of Sciences (CAS), Lanzhou 730000 (China); University of Chinese Academy of Sciences (UCAS), Beijing 100049 (China); Liu, J., E-mail: J.Liu@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences (CAS), Lanzhou 730000 (China); Zhang, S.X. [Institute of Modern Physics, Chinese Academy of Sciences (CAS), Lanzhou 730000 (China); University of Chinese Academy of Sciences (UCAS), Beijing 100049 (China); Maaz, K. [Institute of Modern Physics, Chinese Academy of Sciences (CAS), Lanzhou 730000 (China); Nanomaterials Research Group, Physics Division, PINSTECH, Nilore, 45650 Islamabad (Pakistan); Zeng, J. [Institute of Modern Physics, Chinese Academy of Sciences (CAS), Lanzhou 730000 (China); Guo, H. [Institute of Modern Physics, Chinese Academy of Sciences (CAS), Lanzhou 730000 (China); University of Chinese Academy of Sciences (UCAS), Beijing 100049 (China); Zhai, P.F.; Duan, J.L.; Sun, Y.M.; Hou, M.D. [Institute of Modern Physics, Chinese Academy of Sciences (CAS), Lanzhou 730000 (China)

    2016-04-01

    InP crystals and GaN films were irradiated by swift heavy ions {sup 86}Kr and {sup 209}Bi with kinetic energies of 25 and 9.5 MeV per nucleon and ion fluence in the range 5 × 10{sup 10} to 3.6 × 10{sup 12} ions/cm{sup 2}. The characteristic optical bands were studied by Raman spectroscopy to reveal the disorder and defects induced in the samples during the irradiation process. The crystallinity of InP and GaN was found to be deteriorated after irradiation by the swift heavy ions and resulted in the amorphous nature of the samples along the ion tracks. The amorphous tracks observed by transmission electron microscopy (TEM) images confirmed the formation of lattice defects. In typical F{sub 2}(LO) mode, in case of InP, the spectra shifted towards the lower wavenumbers with a maximum shift of 7.6 cm{sup −1} induced by 1030 MeV Bi ion irradiation. While in case of GaN, the typical E{sub 2}(high) mode shifted towards the higher wavenumbers, with maximum shift of 5.4 cm{sup −1} induced by 760 MeV Bi ion irradiation at ion fluence of 1 × 10{sup 12} ions/cm{sup 2}. The observed Raman shifts reveal the presence of lattice defects and disorder induced in the samples after irradiation by the swift heavy ions. This irradiation also generated lattice stress in the samples, which has been investigated and discussed in detail in this work.

  3. Study of irradiation induced defects and phase instability in β phase of Zr Excel alloy with in-situ heavy ion irradiation

    International Nuclear Information System (INIS)

    Yu, H.; Yao, Z.; Kirk, M.A.; Daymond, M.R.

    2015-01-01

    In situ heavy ion irradiation with 1 MeV Kr"2"+ was carried out to study irradiation induced phase change and atomic lattice defects in theβ phase of Zr Excel alloy. No decomposition of β-Zr was observed under irradiation at either 200 "oC or 450 "oC. However, ω-Zr particles experienced shape change and shrinkage associated enrichment of Fe in the β/ω interface at 200 "oC irradiation but not at 450 "oC. The defect evolution in the β-phase was examined with single phase Zr-20Nb alloy. It was found that dislocation loops with Burgers vector 1/2 and both present in β-Zr under room temperature irradiation. (author)

  4. Study of irradiation induced defects and phase instability in β phase of Zr Excel alloy with in-situ heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yu, H.; Yao, Z., E-mail: 12hy1@queensu.ca [Queen' s University, Department of Mechanical and Materials Engineering, Kingston, ON (Canada); Kirk, M.A. [Argonne National Laboratory, Materials Science Division, Argonne, IL (United States); Daymond, M.R. [Queen' s University, Department of Mechanical and Materials Engineering, Kingston, ON (Canada)

    2015-07-01

    In situ heavy ion irradiation with 1 MeV Kr{sup 2+} was carried out to study irradiation induced phase change and atomic lattice defects in theβ phase of Zr Excel alloy. No decomposition of β-Zr was observed under irradiation at either 200 {sup o}C or 450 {sup o}C. However, ω-Zr particles experienced shape change and shrinkage associated enrichment of Fe in the β/ω interface at 200 {sup o}C irradiation but not at 450 {sup o}C. The defect evolution in the β-phase was examined with single phase Zr-20Nb alloy. It was found that dislocation loops with Burgers vector 1/2<111> and <001> both present in β-Zr under room temperature irradiation. (author)

  5. Genetic variation of soybean agronomic characters induced by irradiation of seed

    International Nuclear Information System (INIS)

    He Zhihong; Wang Jinling

    1988-02-01

    Dry seeds of three soybean varieties were irradiated by 60 Co γ ray with dosage of 4.1C/kg. The varieties irradiated were Fengshou No. 10, Donghong 74-403 and Heinong No. 26, and nonirradiated seeds of the corresponding variety was used as a control. The following genetic parameters of the nine agronomic characters were estimated, including genotypic coefficient of variation, genotypic variance, broad sense heritanility and genetic advance expected through selection. Three types of plant in M 2 and M 3 were used for the estimation of these parameters which comprise semisterility (MS), fertility (MF) in M 1 and control (CK). The genetic advance expected through selection was compared with the actual effect of selection for date of maturity, seed weigh per plant and 100 seed wight. The pattern of the genetic variation in the early generations of the induced population was analysed. Problems of selection for main agronomic characters in the early generations, and significance of fertility of M 1 plants for mutation breeding were discussed

  6. Long-term Observation of Regenerated Periodontium Induced by FGF-2 in the Beagle Dog 2-Wall Periodontal Defect Model.

    Directory of Open Access Journals (Sweden)

    Jun Anzai

    Full Text Available The long-term stability and qualitative characteristics of periodontium regenerated by FGF-2 treatment were compared with normal physiological healing tissue controls in a Beagle dog 2-wall periodontal defect model 13 months after treatment by assessing tissue histology and three-dimensional microstructure using micro-computed tomography (μCT. After FGF-2 (0.3% or vehicle treatment at the defect sites, serial changes in the bone mineral content (BMC were observed using periodic X-ray imaging. Tissues were harvested at 13 months, evaluated histomorphometrically, and the cortical bone volume and trabecular bone structure of the newly formed bone were analyzed using μCT. FGF-2 significantly increased the BMC of the defect area at 2 months compared with that of the control group, and this difference was unchanged through 13 months. The cortical bone volume was significantly increased by FGF-2, but there was no difference between the groups in trabecular bone structure. Bone maturation was occurring in both groups because of the lower cortical volume and denser trabecular bone than what is found in intact bone. FGF-2 also increased the area of newly formed bone as assessed histomorphometrically, but the ratios of trabecular bone in the defect area were similar between the control and FGF-2 groups. These results suggest that FGF-2 stimulates neogenesis of alveolar bone that is of similar quality to that of the control group. The lengths of the regenerated periodontal ligament and cementum, measured as the distance from the defect bottom to the apical end of the gingival epithelium, and height and area of the newly formed bone in the FGF-2 group were larger than those in the control group. The present study demonstrated that, within the limitation of artificial periodontal defect model, the periodontal tissue regenerated by FGF-2 was maintained for 13 months after treatment and was qualitatively equivalent to that generated through the physiological

  7. Genetic Variant in Flavin-Containing Monooxygenase 3 Alters Lipid Metabolism in Laying Hens in a Diet-Specific Manner

    OpenAIRE

    Wang, Jing; Long, Cheng; Zhang, Haijun; Zhang, Yanan; Wang, Hao; Yue, Hongyuan; Wang, Xiaocui; Wu, Shugeng; Qi, Guanghai

    2016-01-01

    Genetic variant T329S in flavin-containing monooxygenase 3 (FMO3) impairs trimethylamine (TMA) metabolism in birds. The TMA metabolism that under complex genetic and dietary regulation, closely linked to cardiovascular disease risk. We determined whether the genetic defects in TMA metabolism may change other metabolic traits in birds, determined whether the genetic effects depend on diets, and to identify genes or gene pathways that underlie the metabolic alteration induced by genetic and die...

  8. Genetics

    DEFF Research Database (Denmark)

    Christensen, Kaare; McGue, Matt

    2016-01-01

    The sequenced genomes of individuals aged ≥80 years, who were highly educated, self-referred volunteers and with no self-reported chronic diseases were compared to young controls. In these data, healthy ageing is a distinct phenotype from exceptional longevity and genetic factors that protect...

  9. Defect of Fe-S cluster binding by DNA polymerase δ in yeast suppresses UV-induced mutagenesis, but enhances DNA polymerase ζ - dependent spontaneous mutagenesis.

    Science.gov (United States)

    Stepchenkova, E I; Tarakhovskaya, E R; Siebler, H M; Pavlov, Y I

    2017-01-01

    Eukaryotic genomes are duplicated by a complex machinery, utilizing high fidelity replicative B-family DNA polymerases (pols) α, δ and ε. Specialized error-prone pol ζ, the fourth B-family member, is recruited when DNA synthesis by the accurate trio is impeded by replication stress or DNA damage. The damage tolerance mechanism dependent on pol ζ prevents DNA/genome instability and cell death at the expense of increased mutation rates. The pol switches occurring during this specialized replication are not fully understood. The loss of pol ζ results in the absence of induced mutagenesis and suppression of spontaneous mutagenesis. Disruption of the Fe-S cluster motif that abolish the interaction of the C-terminal domain (CTD) of the catalytic subunit of pol ζ with its accessory subunits, which are shared with pol δ, leads to a similar defect in induced mutagenesis. Intriguingly, the pol3-13 mutation that affects the Fe-S cluster in the CTD of the catalytic subunit of pol δ also leads to defective induced mutagenesis, suggesting the possibility that Fe-S clusters are essential for the pol switches during replication of damaged DNA. We confirmed that yeast strains with the pol3-13 mutation are UV-sensitive and defective in UV-induced mutagenesis. However, they have increased spontaneous mutation rates. We found that this increase is dependent on functional pol ζ. In the pol3-13 mutant strain with defective pol δ, there is a sharp increase in transversions and complex mutations, which require functional pol ζ, and an increase in the occurrence of large deletions, whose size is controlled by pol ζ. Therefore, the pol3-13 mutation abrogates pol ζ-dependent induced mutagenesis, but allows for pol ζ recruitment for the generation of spontaneous mutations and prevention of larger deletions. These results reveal differential control of the two major types of pol ζ-dependent mutagenesis by the Fe-S cluster present in replicative pol δ. Copyright © 2016

  10. 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

  11. Mn fraction substitutional site and defects induced magnetism in Mn-implanted 6H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Bouziane, K., E-mail: Khalid.bouziane@uir.ac.ma [Pôle Energies Renouvelables et Etudes Pétrolières, Université Internationale de Rabat, 11000 – Salé el Jadida, Technopolis (Morocco); Al Azri, M.; Elzain, M. [Department of Physics, College of Science, Sultan Qaboos University, P.O. Box 36, Al-Khodh 123 (Oman); Chérif, S.M. [LSPM (CNRS-UPR 3407), Université Paris, 13-Nord, 99, Avenue Jean Baptiste Clément, 93430 Villetaneuse (France); Mamor, M. [Equipe MSISM, Faculté Poly-Disciplinaire, B.P. 4162 Safi, Université Cadi Ayyad, Marrakech (Morocco); Declémy, A. [Institut P’, CNRS – Université de Poitiers – ENSMA, UPR 3346, SP2MI – Téléport 2, 11 boulevard Marie et Pierre Curie, BP 30179, F-86962 Futuroscope Chasseneuil Cedex (France); Thomé, L. [CSNSM-Orsay, Bât. 108, Université d’Orsay, F-91405 Orsay (France)

    2015-05-25

    Highlights: • Shallow Mn-implanted 6H-SiC crystal. • Correlation between Mn-substitutional site concentration and magnetism. • Correlation between defects nature surrounding Mn site and magnetism. • Correlation of magnetism in Mn-doped SiC to Mn at Si sites and vacancy-related defect. - Abstract: n-type 6H-SiC (0 0 0 1) single crystal substrates were implanted with three fluences of manganese (Mn{sup +}) ions: 5 × 10{sup 15}, 1 × 10{sup 16} and 5 × 10{sup 16} cm{sup −2} with implantation energy of 80 keV at 365 °C to stimulate dynamic annealing. The samples were characterized using Rutherford backscattering channeling spectroscopy (RBS/C), high-resolution X-ray diffraction technique (HRXRD), and Superconducting Quantum Interference Device (SQUID) techniques. Two main defect regions have been identified using RBS/C spectra fitted with the McChasy code combined to SRIM simulations. Intermediate defects depth region is associated with vacancies (D{sub V}) and deeper defect (D{sub N}) essentially related to the Si and C interstitial defects. The defect concentration and the maximum perpendicular strain exhibit similar increasing trend with the Mn{sup +} fluence. Furthermore, the amount of Mn atoms at Si substitutional sites and the corresponding magnetic moment per Mn atom were found to increase with increasing Mn fluence from 0.7 μ{sub B} to 1.7 μ{sub B} and then collapsing to 0.2 μ{sub B}. Moreover, a strong correlation has been found between the magnetic moment and the combination of both large D{sub V}/D{sub N} ratio and high Mn at Si sites. These results are corroborated by our ab initio calculations considering the most stable configurations showing that besides the amount of Mn substituting Si sites, local vacancy-rich environment is playing a crucial role in enhancing the magnetism.

  12. Genetic analysis of a Y-chromosome region that induces</